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Which drugs are included in the Lonsurf combination pill? | Lonsurf is an oral fixed dose combination of trifluridine and tipiracil that is used for cancer treatment. | Evolocumab (Repatha) for patients with hypercholesterolemia whose condition has
not been controlled by statins and other therapies; trifluridine/tipiracil
(Lonsurf) for metastatic colorectal cancer; and blood coagulation factor VIII
(Nuwiq) for adults and children with hemophilia A. Within the past several years, no chemotherapy has been sufficient to increase
the overall survival of patients with chemorefractory colorectal cancer. TAS-102
(Lonsurf) is an oral fluoropyrimidine that is formed by the combination of 2
active drugs: trifluridine (a nucleoside analog) and tipiracil hydrochloride (a
thymidine phosphorylase inhibitor). This drug extended the median overall
survival by approximately 2 months compared with placebo in a randomized phase
III trial composed of Asian and non-Asian patients with refractory (or
intolerant) metastatic colorectal cancer. The clinical development of TAS-102
began approximately a decade ago and included 2 pivotal randomized studies,
which are discussed in this review. This drug has just been approved in Japan,
and as soon as possible, it will be marketed in Western countries as well; it
will therefore become the standard of care for this patient population. The
optimal combination of TAS-102 with other agents, as well as the mechanism of
resistance to this regimen should be defined in the near future. Trifluridine/tipiracil (Lonsurf(®)) is a novel, orally active, antimetabolite
agent comprised of trifluridine, a thymidine-based nucleoside analogue, and
tipiracil, a potent thymidine phosphorylase inhibitor. Trifluridine is
incorporated into DNA via phosphorylation, ultimately inhibiting cell
proliferation. Tipiracil increases systemic exposure of trifluridine when
coadministered. Trifluridine/tipiracil has recently been approved for the
treatment of adult patients with metastatic colorectal cancer (mCRC) who are
refractory to or are not considered candidates for, current standard
chemotherapy and biological therapy in the EU and USA and in unresectable
advanced or recurrent CRC in Japan. The approved regimen of oral twice-daily
trifluridine/tipiracil (35 mg/m(2) twice daily on days 1-5 and 8-12 of each
28-day cycle) significantly improved overall survival and progression-free
survival and was associated with a significantly higher disease control rate
than placebo when added to best supportive care in the multinational, pivotal
phase III trial (RECOURSE) and a phase II Japanese trial. Trifluridine/tipiracil
was associated with an acceptable tolerability profile, with adverse events
generally being managed with dose reductions, temporary interruptions in
treatment or administration of granulocyte-colony stimulating factor. The most
common grade 3-4 adverse events (≥10 %) were anaemia, neutropenia,
thrombocytopenia and leukopenia. In conclusion, trifluridine/tipiracil is a
useful additional treatment option for the management of mCRC in patients who
are refractory to, or are not considered candidates for, currently available
therapies. BACKGROUND: Treatment-related adverse events (AEs) are common in patients with
metastatic colorectal cancer (mCRC) receiving chemotherapy. These AEs may affect
patient adherence, particularly with completely oral regimens, such as
trifluridine/tipiracil (TAS-102, Lonsurf®), an antimetabolite agent for patients
with mCRC refractory or intolerant to standard therapies.
.
OBJECTIVES: This article reviews strategies for promoting adherence and
educating patients and caregivers about oral therapy with
trifluridine/tipiracil.
.
METHODS: Recommended strategies for managing AEs are reviewed, with a focus on
the most common AEs reported in patients with mCRC receiving
trifluridine/tipiracil in clinical trials.
.
FINDINGS: Oncology nurses play an important role in educating and counseling
patients regarding treatment and its potential side effects. Among patients with
mCRC refractory or intolerant to standard therapies, trifluridine/tipiracil was
found to have a favorable safety profile. It is associated with hematologic AEs
as well as a low incidence of nausea, diarrhea, vomiting, anorexia, and fatigue. BACKGROUND: Trifluridine/tipiracil (TAS-102, Lonsurf®), a novel oral anti-tumor
agent combining an anti-neoplastic thymidine-based nucleoside analogue
(trifluridine, FTD) with a thymidine phosphorylase inhibitor (tipiracil
hydrochloride, TPI) presents a new treatment option for metastatic colorectal
cancer (mCRC) patients refractory or intolerant to standard therapies. FTD/TPI
was approved in the European Union (EU) in April 2016 and launched on the German
market in August 15, 2016.
METHODS: We investigated the characteristics of patients (pts) with mCRC treated
with FTD/TPI at 118 centers in Germany from January 12 to August 14, 2016 and
analyzed the safety in a clinical real-world setting.
RESULTS: In Germany, a total of 226 mCRC patients were included into a
compassionate-use-program (CUP) and received FTD/TPI. For 45.5% of patients
(n = 101), 253 adverse events (AE) were documented, most of them drug-related
(n = 135). From January 12 (2016) to March 2 (2017), 124 serious adverse events
(SAE) were reported (74 drug related). The most common serious adverse drug
reactions (SADR) were leukopenia (12 events), neutropenia (8 events), anemia (7
events), diarrhea and nausea (5 events each) (observation period January 12 2016
to October 7 2016). In total, 122 patients (54%) discontinued FTD/TPI treatment,
mostly due to progression (n = 75) followed by AEs (n = 21), deaths (n = 16),
and non-specified reasons (n = 16). Interestingly, 12 patients with ECOG PS ≥2
achieved up to 3 cycles of FTD/TPI and in this patient population only 3
treatment discontinuations due to AEs were documented and the safety profile was
comparable to the entire population.
CONCLUSION: The patient characteristics as well as the safety profile of FTD/TPI
documented in the German CUP were consistent with those reported in the pivotal
trial RECOURSE without unexpected safety signals. Background: The treatment options for patients with therapy refractory
metastatic colorectal cancer (mCRC) are sparse. TAS-102 (FTD/TPI) is a new oral
anti-tumour agent composed of a nucleoside analogue, trifluridine, and a
thymidine phosphorylase inhibitor, tipiracil, indicated for patients with mCRC
who are refractory to standard therapies. This study summarizes published and
unpublished experience with FTD/TPI in clinical practice settings. Patients and
methods: The Medline/PubMed, Embase and Cochrane Library databases were searched
to identify observational studies on FTD/TPI monotherapy for mCRC. Papers
describing use of FTD/TPI monotherapy outside clinical trials in series of
patients evaluable for effectiveness were eligible. The outcomes of interest
were median progression free survival (mPFS), median overall survival (mOS) as
well as mean PFS time restricted to six months (PFS6m) and mean OS time
restricted to one year (OS1y). Results of the pooled analyses of observational
studies were compared to the results of the Japanese phase II trial and the two
phase III trials, RECOURSE and TERRA. Results: Seven published and two
unpublished studies with 1008 patients from 64 centres were included for
analysis. The pooled mPFS was 2.2 months (95% CI 2.1 to 2.3 months), and the
pooled mOS was 6.6 months (95% CI 6.1 to 7.1 months). PFS6m was 2.9 months (95%
CI 2.6 to 3.1 months) and OS1y was 6.8 (95% CI 6.0 to 7.5) months. While these
results all reflect RECOURSE, the pooled mOS is lower than in the phase II trial
and the OS1y is inferior to both the phase II trial and TERRA. Conclusion: This
systematic review and a meta-analysis indicates that in real life settings, the
survival benefit of FTD/TPI monotherapy in patients with therapy refractory mCRC
reflects the outcomes in RECOURSE but is inferior to outcomes in the two Asian
efficacy trials. What is already known TAS 102 (Lonsurf) is an oral fixed dose
combination of trifluridine (FTD) and tipiracil (TPI) indicated as salvage-line
treatment in patients with therapy refractory metastatic colorectal cancer
(mCRC). A Japanese phase II trial and two phase III trials, RECOURSE and TERRA,
demonstrated that FTD/TPI prolonged overall survival. What this study adds This
systematic review and meta-analysis of real life data from 64 sites indicates
that the effectiveness in daily clinical practice settings of FTD/TPI
monotherapy in late stage mCRC reflects the outcomes in RECOURCE but is inferior
to the outcomes in the Japanese phase II trial and TERRA. Trifluridine/tipiracil (Lonsurf®) is a fixed-dose combination tablet comprising
trifluridine, an antineoplastic nucleoside analogue, and tipiracil, a thymidine
phosphorylase inhibitor. Trifluridine/tipiracil has recently been granted an
additional indication in the USA for the treatment of metastatic gastric cancer,
including gastroesophageal junction adenocarcinoma, in patients who have been
previously treated with at least two systemic treatment regimens, and has
received a positive opinion for this indication in the EU. In the large pivotal
phase III TAGS trial, trifluridine/tipiracil plus best supportive care (BSC)
significantly prolonged overall survival (OS; primary endpoint) compared with
placebo plus BSC in this patient group. Progression-free survival (PFS) and the
disease control rate were also improved with trifluridine/tipiracil relative to
placebo. Health-related quality of life was not adversely affected by the
addition of trifluridine/tipiracil to BSC and time to deterioration of Eastern
Cooperative Oncology Group (ECOG) performance status was significantly delayed.
The most common adverse events were mainly haematological (neutropenia,
leucopenia and anaemia) and gastrointestinal (nausea, vomiting and diarrhoea),
and were generally manageable with dosage modifications and/or supportive care.
Adverse events ≥ Grade 3 were most frequently haematological in nature. Thus,
trifluridine/tipiracil provides a valuable and much needed treatment option for
patients with metastatic gastric or gastroesophageal junction adenocarcinoma
that has progressed on at least two prior therapies. Trifluridine/tipiracil or TAS-102 (Taiho Oncology, Lonsurf®, Princeton, NJ, USA)
is a combination tablet of trifluridine, a thymidine-based nucleoside analog,
and tipiracil, a thymidine phosphorylase inhibitor, in a 1:0.5 molar ratio. This
drug was first approved for use in metastatic colorectal cancer patients.
Recently, the U S Food and Drug Administration (FDA) and the European Medicines
Agency (EMA) have granted approval of trifluridine/tipiracil for treatment of
metastatic gastric and gastroesophageal junction adenocarcinoma in patients
following at least two lines of chemotherapy including fluoropyrimidine and
platinum chemotherapy agents, as well as taxanes or irinotecan. This approval
was granted after the findings from first a Phase II trial (EPOC1201)
investigating trifluridine/tipiracil, and later a global Phase III trial (TAGS
trial) that compared trifluridine/tipiracil vs placebo with best supportive
care. Both trials primarily utilized trifluridine/tipiracil at a dose of 35
mg/m2 twice daily. In the EPOC1201 trial, the primary end point of disease
control rate was greater than 50% after eight weeks of therapy. The most common
grade three or four adverse event was neutropenia; additional toxicities
included leukopenia, anemia, and anorexia. In the TAGS trial, overall survival
in patients treated with trifluridine/tipiracil (5.7 months) was significantly
improved as compared to the placebo-controlled group (3.6 months). Treatment
with trifluridine/tipiracil not only did not impair quality of life but also
tended to reduce the risk of deterioration of quality of life. The results of
these studies along with the subsequent FDA and EMA approval have generated an
important breakthrough in regard to treatment options for patients with
refractory metastatic gastric or gastroesophageal junction adenocarcinoma. TAS-102/Lonsurf is a new oral anti-tumor drug consisting of trifluridine and
tipiracil in a 1:0.5 molar ratio. Lonsurf has been approved globally, including
US, Europe Union, and China, to treat patients with advanced colorectal cancer.
Ongoing clinical trials are currently conducted for the treatment of other solid
cancers. However, the therapeutic potential of TAS-102 in hematological
maligcies has not been explored. In this study, we investigate the
therapeutic efficacy of TAS-102 in multiple myeloma both in vitro and in vivo.
We demonstrate that TAS-102 treatment inhibits tumor cell proliferation in six
human myeloma cell lines with IC50 values in a range from 0.64 to 9.10 μM. Dot
blotting and immunofluorescent staining show that trifluridine is predominately
incorporated into genomic DNAs of myeloma cells. TAS-102 treatment induces
myeloma cell apoptosis through cell cycle arrest in G1 phase and activation of
cGAS-STING signaling in myeloma cells. In the human myeloma xenograft models,
TAS-102 treatment reduces tumor progression and prolongs mouse survival. TAS-102
has shown its efficacies in the drug-resistant myeloma cells, and the
combination of TAS-102 and bortezomib has a synergistic anti-myeloma activity.
Our preclinical studies indicate that TAS-102 is a potential novel agent for
myeloma therapy. TAGS trial revealed the efficacy and safety of
trifluridine/tipiracil(Lonsurf®)treatment in patients with metastatic gastric
cancer following gastrectomy. Here, we successfully treated 38 months survival
case after recurrences following radical gastrectomy for advanced adenocarcinoma
of esophago-gastric junction using historical recommended chemotherapy regimens
and trifluridine/tipiracil as a fifth-line chemotherapy. Trifluridine/tipiracil
therapy contributed to effective and safety treatment even in late-line
chemotherapy for recurrent gastric cancer. In the RECOURSE trial which lead to its accreditation, Lonsurf
(trifluridine/tipiracil) was shown to extend progression free survival (PFS) by
1.8 months in metastatic colorectal cancer. This Trust audit aims to assess the
average quantity of cycles of Lonsurf received by participants and the length of
time it extends PFS. Similarly, to identify how many participants required a
dose-reduction or experienced toxicities which necessitated supportive
therapies. Quantitative data was collected retrospectively from all participants
who had received ≥1 cycle of Lonsurf from The Clatterbridge Cancer Centre (CCC)
from 2016 until June 2020. Participant electronic patient records were accessed
to identify toxicity grading, length of treatment received, the date progression
was identified, if dose reductions were applied and if supportive therapies were
administered. Lonsurf extends PFS in patients with metastatic colorectal cancer
at CCC by 3.0 months (95% CI: 2.73-3.27) and average treatment length was
2.4 months. However, 78 participants (41.5%) received a dose reduction due to
toxicities. A total of 955 toxicities were recorded by participants; the most
commonly reported toxicities irrespective of grade were fatigue (33.8%),
diarrhoea (13.8%) and nausea (12.3%). The most common grade ≥3 toxicities were
constipation and infection. The most frequently utilised supportive therapies
were loperamide (49.6%) and domperidone (49.1%). Granulocyte colony stimulating
factor (GCSF) was required by patients on 5 occasions (0.3%) in total. Lonsurf
extends median PFS in patients with metastatic colorectal cancer by 3.0 months.
The most common grade ≥3 toxicities which necessitated supportive therapies or a
dose reduction were gastrointestinal and infection. |
What is the correlation of Cathepsin L and COVID-19? | Cathepsin L (CTSL) is a kind of the SARS-entry-associated CoV-2's proteases, which plays a key role in the virus's entry into the cell and subsequent infection | The ongoing pandemic illustrates limited therapeutic options for controlling
SARS-CoV-2 infections, calling a need for additional therapeutic targets. The
viral spike S glycoprotein binds to the human receptor angiotensin-converting
enzyme 2 (ACE2) and then is activated by the host proteases. Based on the
accessibility of the cellular proteases needed for SARS-S activation, SARS-CoV-2
entrance and activation can be mediated by endosomal (such as cathepsin L) and
non-endosomal pathways. Evidence indicates that in the non-endosomal pathway,
the viral S protein is cleaved by the furin enzyme in infected host cells. To
help the virus enter efficiently, the S protein is further activated by the
serine protease 2 (TMPRSS2), provided that the S has been cleaved by furin
previously. In this review, important roles for host proteases within host cells
will be outlined in SARS-CoV-2 infection and antiviral therapeutic strategies
will be highlighted. Although there are at least five highly effective vaccines
at this time, the appearance of the new viral mutations demands the development
of therapeutic agents. Targeted inhibition of host proteases can be used as a
therapeutic approach for viral infection. INTRODUCTION: Cathepsin L (CTSL) is a kind of the SARS-entry-associated CoV-2's
proteases, which plays a key role in the virus's entry into the cell and
subsequent infection. We investigated the association between the expression
level of CTSL and overall survival in Glioblastoma multiforme (GBM) patients, to
better understand the possible route and risks of new coronavirus infection for
patients with GBM.
METHODS: The expression level of CTSL in GBM was analyzed using TCGA and CGGA
databases. The relationship between CTSL and immune infiltration levels was
analyzed by means of the TIMER database. The impact of CTSL inhibitors on GBM
biological activity was tested.
RESULTS: The findings revealed that GBM tissues had higher CTSL expression
levels than that of normal brain tissues, which was associated with a
significantly lower survival rate in GBM patients. Meanwhile, the expression
level of CTSL negatively correlated with purity, B cell and CD8+ T cell in GBM.
CTSL inhibitor significantly reduced growth and induced mitochondrial apoptosis.
CONCLUSION: According to the findings, CTSL acts as an independent prognostic
factor and can be considered as promising therapeutic target for GBM. |
Is autism thought to be related to the Arginine Vasopressin Peptide (AVP)? | Differences in vasopressin levels in individuals suffering from the autism spectrum disorders have been demonstrated. | Impaired reciprocal social interaction is one of the core features of autism.
While its determits are complex, one biomolecular pathway that clearly
influences social behavior is the arginine-vasopressin (AVP) system. The
behavioral effects of AVP are mediated through the AVP receptor 1a (AVPR1a),
making the AVPR1a gene a reasonable candidate for autism susceptibility. We
tested the gene's contribution to autism by screening its exons in 125
independent autistic probands and genotyping two promoter polymorphisms in 65
autism affected sibling pair (ASP) families. While we found no nonconservative
coding sequence changes, we did identify evidence of linkage and of linkage
disequilibrium. These results were most pronounced in a subset of the ASP
families with relatively less severe impairment of language. Thus, though we did
not demonstrate a disease-causing variant in the coding sequence, numerous
nontraditional disease-causing genetic abnormalities are known to exist that
would escape detection by traditional gene screening methods. Given the emerging
biological, animal model, and now genetic data, AVPR1a and genes in the AVP
system remain strong candidates for involvement in autism susceptibility and
deserve continued scrutiny. BACKGROUND: Dysregulation of the vasopressin (AVP) system has been implicated in
the pathogenesis of autistic spectrum disorder (ASD). Apelin is a recently
discovered neuropeptide that could counteract AVP actions and whose receptors
are colocalized with vasopressin in hypothalamic magnocellular neurons. Aims of
the present study were to investigate circulating levels of apelin in patients
with ASD and to assess their correlation with plasma AVP concentrations.
METHODS: Plasma levels of apelin and AVP were measured in a total of 18 patients
with ASD and 21 age- and gender-matched healthy comparison subjects. The
Childhood Autism Rating Scale (CARS) was used to assess the severity of autistic
symptoms.
RESULTS: Significantly reduced levels of apelin (p < 0.001) and elevated
concentrations of AVP (p = 0.02) were found in ASD patients as compared to
controls. Additionally, a significant inverse correlation between apelin and AVP
levels was found within the ASD group (r = -0.61; p = 0.007), but not in healthy
participants (r = -0.26; p = 0.25). Multivariate linear regression analysis
showed that only AVP concentrations independently predicted apelin values in ASD
individuals (beta = -0.42, t = 2.63, p = 0.014). No correlation was seen between
apelin levels and CARS scores (r = -0.10; p = 0.68).
CONCLUSIONS: Our findings of a significantly reduced peripheral level of apelin
coupled with elevated AVP point to a subtle but definite vasopressinergic
dysfunction in autism that could play a role in the etiopathophysiology of this
disorder in humans. Oxytocin (OT) and arginine-vasopressin (AVP) are 2 peptides that are produced in
the brain and released via the pituitary gland to the peripheral blood, where
they have diverse physiological functions. In the last 2 decades it has become
clear that these peptides also play a central role in the modulation of
mammalian social behavior by their actions within the brain. Several lines of
evidence suggest their involvement in autism spectrum disorder (ASD), which is
known to be associated with impaired social cognition and behavior. Recent
clinical trials using OT administration to autistic patients have reported
promising results. Here, we aim to describe the main data that suggest a
connection between these peptides and ASD. Following a short illustration of
several major topics in ASD biology we will (a) briefly describe the
oxytocinergic and vasopressinergic systems in the brain, (b) discuss a few
compelling cases manifesting the involvement of OT and AVP in mammalian social
behavior, (c) describe data supporting the role of these peptides in human
social cognition and behavior, and (d) discuss the possibility of the
involvement of OT and AVP in ASD etiology, as well as the prospect of using
these peptides as a treatment for ASD patients. BACKGROUND: Arginine vasopressin (AVP) has been hypothesized to play a role in
aetiology of autism based on a demonstrated involvement in the regulation of
social behaviours. The arginine vasopressin receptor 1A gene (AVPR1A) is widely
expressed in the brain and is considered to be a key receptor for regulation of
social behaviour. Moreover, genetic variation at AVPR1A has been reported to be
associated with autism. Evidence from non-human mammals implicates variation in
the 5'-flanking region of AVPR1A in variable gene expression and social
behaviour.
METHODS: We examined four tagging single nucleotide polymorphisms (SNPs)
(rs3803107, rs1042615, rs3741865, rs11174815) and three microsatellites (RS3,
RS1 and AVR) at the AVPR1A gene for association in an autism cohort from
Ireland. Two 5'-flanking region polymorphisms in the human AVPR1A, RS3 and RS1,
were also tested for their effect on relative promoter activity.
RESULTS: The short alleles of RS1 and the SNP rs11174815 show weak association
with autism in the Irish population (P = 0.036 and P = 0.008, respectively).
Both RS1 and RS3 showed differences in relative promoter activity by length.
Shorter repeat alleles of RS1 and RS3 decreased relative promoter activity in
the human neuroblastoma cell line SH-SY5Y.
CONCLUSIONS: These aligning results can be interpreted as a functional route for
this association, namely that shorter alleles of RS1 lead to decreased AVPR1A
transcription, which may proffer increased susceptibility to the autism
phenotype. There has been intensified interest in the neuropeptides oxytocin (OT) and
arginine vasopressin (AVP) in autism spectrum disorders (ASD) given their role
in affiliative and social behavior in animals, positive results of treatment
studies using OT, and findings that genetic polymorphisms in the AVP-OT pathway
are present in individuals with ASD. Nearly all such studies in humans have
focused only on males. With this preliminary study, we provide basic and novel
information on the involvement of OT and AVP in autism, with an investigation of
blood plasma levels of these neuropeptides in 75 preadolescent and adolescent
girls and boys ages 8-18: 40 with high-functioning ASD (19 girls, 21 boys) and
35 typically developing children (16 girls, 19 boys). We related neuropeptide
levels to social, language, repetitive behavior, and internalizing symptom
measures in these individuals. There were significant gender effects: Girls
showed higher levels of OT, while boys had significantly higher levels of AVP.
There were no significant effects of diagnosis on OT or AVP. Higher OT values
were associated with greater anxiety in all girls, and with better pragmatic
language in all boys and girls. AVP levels were positively associated with
restricted and repetitive behaviors in girls with ASD but negatively
(nonsignificantly) associated with these behaviors in boys with ASD. Our results
challenge the prevailing view that plasma OT levels are lower in individuals
with ASD, and suggest that there are distinct and sexually dimorphic mechanisms
of action for OT and AVP underlying anxiety and repetitive behaviors. Autism Res
2013, 6: 91-102. © 2013 International Society for Autism Research, Wiley
Periodicals, Inc. Autism Spectrum Disorders (ASD) are characterized by: social and communication
impairments, and by restricted repetitive behaviors. The aim of the present
paper is to review abnormalities of oxytocin (OXT) and related congenital
malformations in ASD. A literature search was conducted in the PubMed database
up to 2016 for articles related to the pathomechanism of ASD, abnormalities of
OXT and the OXT polymorphism in ASD. The pathomechanism of ASD has yet to be.
The development of ASD is suggested to be related to abnormalities of the
oxytocin-arginin-vasopressin system. Previous results suggest that OXT and
arginine vasopressin (AVP) may play a role in the etiopathogenesis of ASD. Dysfunction of brain-derived arginine-vasopressin (AVP) systems may be involved
in the etiology of autism spectrum disorder (ASD). Certain regions such as the
hypothalamus, amygdala, and hippocampus are known to contain either AVP neurons
or terminals and may play an important role in regulating complex social
behaviors. The present study was designed to investigate the concomitant changes
in autistic behaviors, circulating AVP levels, and the structure and functional
connectivity (FC) of specific brain regions in autistic children compared with
typically developing children (TDC) aged from 3 to 5 years. The results showed:
(1) children with ASD had a significantly increased volume in the left amygdala
and left hippocampus, and a significantly decreased volume in the bilateral
hypothalamus compared to TDC, and these were positively correlated with plasma
AVP level. (2) Autistic children had a negative FC between the left amygdala and
the bilateral supramarginal gyri compared to TDC. The degree of the negative FC
between amygdala and supramarginal gyrus was associated with a higher score on
the clinical autism behavior checklist. (3) The degree of negative FC between
left amygdala and left supramarginal gyrus was associated with a lowering of the
circulating AVP concentration in boys with ASD. (4) Autistic children showed a
higher FC between left hippocampus and right subcortical area compared to TDC.
(5) The circulating AVP was negatively correlated with the visual and listening
response score of the childhood autism rating scale. These results strongly
suggest that changes in structure and FC in brain regions containing AVP may be
involved in the etiology of autism. An accumulating body of evidence indicates a tight relationship between the
endocrine system and abnormal social behavior. Two evolutionarily conserved
hypothalamic peptides, oxytocin and arginine-vasopressin, because of their
extensively documented function in supporting and regulating affiliative and
socio-emotional responses, have attracted great interest for their critical
implications for autism spectrum disorders (ASD). A large number of controlled
trials demonstrated that exogenous oxytocin or arginine-vasopressin
administration can mitigate social behavior impairment in ASD. Furthermore,
there exists long-standing evidence of severe socioemotional dysfunctions after
hypothalamic lesions in animals and humans. However, despite the major role of
the hypothalamus for the synthesis and release of oxytocin and vasopressin, and
the evident hypothalamic implication in affiliative behavior in animals and
humans, a rather small number of neuroimaging studies showed an association
between this region and socioemotional responses in ASD. This review aims to
provide a critical synthesis of evidences linking alterations of the
hypothalamus with impaired social cognition and behavior in ASD by integrating
results of both anatomical and functional studies in individuals with ASD as
well as in healthy carriers of oxytocin receptor (OXTR) genetic risk variant for
ASD. Current findings, although limited, indicate that morphofunctional
anomalies are implicated in the pathophysiology of ASD and call for further
investigations aiming to elucidate anatomical and functional properties of
hypothalamic nuclei underlying atypical socioemotional behavior in ASD. |
Are there any tools that could predict protein structure considering amino acid sequence? | Yes. Tools such as Jpred, Jnet, Porter 4.0 and PSIPRED Workbench have been developed that predict protein structure based solely on its amino acid sequence, whereas the recently updated Jnet algorithm provides a three-state (alpha-helix, beta-strand and coil) prediction of secondary structure at an accuracy of 81.5%. | Knowledge of the detailed structure of a protein is crucial to our understanding
of the biological functions of that protein. The gap between the number of
solved protein structures and the number of protein sequences continues to widen
rapidly in the post-genomics era due to long and expensive processes for solving
structures experimentally. Computational prediction of structures from amino
acid sequence has come to play a key role in narrowing the gap and has been
successful in providing useful information for the biological research
community. We have developed a prediction pipeline, PROSPECT-PSPP, an
integration of multiple computational tools, for fully automated protein
structure prediction. The pipeline consists of tools for (i) preprocessing of
protein sequences, which includes signal peptide prediction, protein type
prediction (membrane or soluble) and protein domain partition, (ii) secondary
structure prediction, (iii) fold recognition and (iv) atomic structural model
generation. The centerpiece of the pipeline is our threading-based program
PROSPECT. The pipeline is implemented using SOAP (Simple Object Access
Protocol), which makes it easier to share our tools and resources. The pipeline
has an easy-to-use user interface and is implemented on a 64-node dual processor
Linux cluster. It can be used for genome-scale protein structure prediction. The
pipeline is accessible at http://csbl.bmb.uga.edu/protein_pipeline. PreSSAPro is a software, available to the scientific community as a free web
service designed to provide predictions of secondary structures starting from
the amino acid sequence of a given protein. Predictions are based on our
recently published work on the amino acid propensities for secondary structures
in either large but not homogeneous protein data sets, as well as in smaller but
homogeneous data sets corresponding to protein structural classes, i.e.
all-alpha, all-beta, or alpha-beta proteins. Predictions result improved by the
use of propensities evaluated for the right protein class. PreSSAPro predicts
the secondary structure according to the right protein class, if known, or gives
a multiple prediction with reference to the different structural classes. The
comparison of these predictions represents a novel tool to evaluate what
sequence regions can assume different secondary structures depending on the
structural class assignment, in the perspective of identifying proteins able to
fold in different conformations. The service is available at the URL
http://bioinformatica.isa.cnr.it/PRESSAPRO/. MOTIVATION: Predictions of protein local structure, derived from sequence
alignment information alone, provide visualization tools for biologists to
evaluate the importance of amino acid residue positions of interest in the
absence of X-ray crystal/NMR structures or homology models. They are also useful
as inputs to sequence analysis and modeling tools, such as hidden Markov models
(HMMs), which can be used to search for homology in databases of known protein
structure. In addition, local structure predictions can be used as a component
of cost functions in genetic algorithms that predict protein tertiary structure.
We have developed a program (predict-2nd) that trains multilayer neural networks
and have applied it to numerous local structure alphabets, tuning network
parameters such as the number of layers, the number of units in each layer and
the window sizes of each layer. We have had the most success with four-layer
networks, with gradually increasing window sizes at each layer.
RESULTS: Because the four-layer neural nets occasionally get trapped in poor
local optima, our training protocol now uses many different random starts, with
short training runs, followed by more training on the best performing networks
from the short runs. One recent addition to the program is the option to add a
guide sequence to the profile inputs, increasing the number of inputs per
position by 20. We find that use of a guide sequence provides a small but
consistent improvement in the predictions for several different local-structure
alphabets.
AVAILABILITY: Local structure prediction with the methods described here is
available for use online at
http://www.soe.ucsc.edu/compbio/SAM_T08/T08-query.html. The source code and
example networks for PREDICT-2ND are available at
http://www.soe.ucsc.edu/~karplus/predict-2nd/ A required C++ library is
available at http://www.soe.ucsc.edu/~karplus/ultimate/ Prediction of protein secondary structure is an important step towards
elucidating its three dimensional structure and its function. This is a
challenging problem in bioinformatics. Segmental semi Markov models (SSMMs) are
one of the best studied methods in this field. However, incorporating
evolutionary information to these methods is somewhat difficult. On the other
hand, the systems of multiple neural networks (NNs) are powerful tools for
multi-class pattern classification which can easily be applied to take these
sorts of information into account. To overcome the weakness of SSMMs in
prediction, in this work we consider a SSMM as a decision function on outputs of
three NNs that uses multiple sequence alignment profiles. We consider four types
of observations for outputs of a neural network. Then profile table related to
each sequence is reduced to a sequence of four observations. In order to predict
secondary structure of each amino acid we need to consider a decision function.
We use an SSMM on outputs of three neural networks. The proposed SSMM has
discriminative power and weights over different dependency models for outputs of
neural networks. The results show that the accuracy of our model in predictions,
particularly for strands, is considerably increased. Rational peptide design and large-scale prediction of peptide structure from
sequence remain a challenge for chemical biologists. We present PEP-FOLD, an
online service, aimed at de novo modelling of 3D conformations for peptides
between 9 and 25 amino acids in aqueous solution. Using a hidden Markov
model-derived structural alphabet (SA) of 27 four-residue letters, PEP-FOLD
first predicts the SA letter profiles from the amino acid sequence and then
assembles the predicted fragments by a greedy procedure driven by a modified
version of the OPEP coarse-grained force field. Starting from an amino acid
sequence, PEP-FOLD performs series of 50 simulations and returns the most
representative conformations identified in terms of energy and population. Using
a benchmark of 25 peptides with 9-23 amino acids, and considering the
reproducibility of the runs, we find that, on average, PEP-FOLD locates lowest
energy conformations differing by 2.6 A Calpha root mean square deviation from
the full NMR structures. PEP-FOLD can be accessed at
http://bioserv.rpbs.univ-paris-diderot.fr/PEP-FOLD. For naturally occurring proteins, similar sequence implies similar structure.
Consequently, multiple sequence alignments (MSAs) often are used in
template-based modeling of protein structure and have been incorporated into
fragment-based assembly methods. Our previous homology-free structure prediction
study introduced an algorithm that mimics the folding pathway by coupling the
formation of secondary and tertiary structure. Moves in the Monte Carlo
procedure involve only a change in a single pair of phi,psi backbone dihedral
angles that are obtained from a Protein Data Bank-based distribution appropriate
for each amino acid, conditional on the type and conformation of the flanking
residues. We improve this method by using MSAs to enrich the sampling
distribution, but in a manner that does not require structural knowledge of any
protein sequence (i.e., not homologous fragment insertion). In combination with
other tools, including clustering and refinement, the accuracies of the
predicted secondary and tertiary structures are substantially improved and a
global and position-resolved measure of confidence is introduced for the
accuracy of the predictions. Performance of the method in the Critical
Assessment of Structure Prediction (CASP8) is discussed. A wealth of in silico tools is available for protein motif discovery and
structural analysis. The aim of this chapter is to collect some of the most
common and useful tools and to guide the biologist in their use. A detailed
explanation is provided for the use of Distill, a suite of web servers for the
prediction of protein structural features and the prediction of full-atom 3D
models from a protein sequence. Besides this, we also provide pointers to many
other tools available for motif discovery and secondary and tertiary structure
prediction from a primary amino acid sequence. The prediction of protein
intrinsic disorder and the prediction of functional sites and SLiMs are also
briefly discussed. Given that user queries vary greatly in size, scope and
character, the trade-offs in speed, accuracy and scale need to be considered
when choosing which methods to adopt. SUMMARY: Protein secondary structure and solvent accessibility predictions are a
fundamental intermediate step towards protein structure and function prediction.
We present new systems for the ab initio prediction of protein secondary
structure and solvent accessibility, Porter 4.0 and PaleAle 4.0. Porter 4.0
predicts secondary structure correctly for 82.2% of residues. PaleAle 4.0's
accuracy is 80.0% for prediction in two classes with a 25% accessibility
threshold. We show that the increasing training set sizes that come with the
continuing growth of the Protein Data Bank keep yielding prediction quality
improvements and examine the impact of protein resolution on prediction
performances.
AVAILABILITY: Porter 4.0 and PaleAle 4.0 are freely available for academic users
at http://distillf.ucd.ie/porterpaleale/. Up to 64 kb of input in FASTA format
can be processed in a single submission, with predictions now being returned to
the user within a single web page and, optionally, a single email. Protein tertiary structure prediction algorithms aim to predict, from amino acid
sequence, the tertiary structure of a protein. In silico protein structure
prediction methods have become extremely important, as in vitro-based structural
elucidation is unable to keep pace with the current growth of sequence databases
due to high-throughput next-generation sequencing, which has exacerbated the
gaps in our knowledge between sequences and structures.Here we briefly discuss
protein tertiary structure prediction, the biennial competition for the Critical
Assessment of Techniques for Protein Structure Prediction (CASP) and its role in
shaping the field. We also discuss, in detail, our cutting-edge web-server
method IntFOLD2-TS for tertiary structure prediction. Furthermore, we provide a
step-by-step guide on using the IntFOLD2-TS web server, along with some real
world examples, where the IntFOLD server can and has been used to improve
protein tertiary structure prediction and aid in functional elucidation. The PSIPRED Workbench is a web server offering a range of predictive methods to
the bioscience community for 20 years. Here, we present the work we have
completed to update the PSIPRED Protein Analysis Workbench and make it ready for
the next 20 years. The main focus of our recent website upgrade work has been
the acceleration of analyses in the face of increasing protein sequence database
size. We additionally discuss any new software, the new hardware infrastructure,
our webservices and web site. Lastly we survey updates to some of the key
predictive algorithms available through our website. Predicting the three-dimensional structure of proteins is a long-standing
challenge of computational biology, as the structure (or lack of a rigid
structure) is well known to determine a protein's function. Predicting relative
solvent accessibility (RSA) of amino acids within a protein is a significant
step towards resolving the protein structure prediction challenge especially in
cases in which structural information about a protein is not available by
homology transfer. Today, arguably the core of the most powerful prediction
methods for predicting RSA and other structural features of proteins is some
form of deep learning, and all the state-of-the-art protein structure prediction
tools rely on some machine learning algorithm. In this article we present a deep
neural network architecture composed of stacks of bidirectional recurrent neural
networks and convolutional layers which is capable of mining information from
long-range interactions within a protein sequence and apply it to the prediction
of protein RSA using a novel encoding method that we shall call "clipped". The
final system we present, PaleAle 5.0, which is available as a public server,
predicts RSA into two, three and four classes at an accuracy exceeding 80% in
two classes, surpassing the performances of all the other predictors we have
benchmarked. Author information:
(1)TUM (Technical University of Munich) Department of Informatics,
Bioinformatics & Computational Biology - i12, Boltzmannstr 3, 85748
Garching/Munich, Germany.
(2)TUM Graduate School CeDoSIA, Boltzmannstr 11, 85748 Garching, Germany.
(3)Luxembourg Centre For Systems Biomedicine (LCSB), University of Luxembourg,
Campus Belval, House of Biomedicine II, 6 avenue du Swing, L-4367 Belvaux,
Luxembourg.
(4)ELIXIR Luxembourg (ELIXIR-LU) Node, University of Luxembourg, Campus Belval,
House of Biomedicine II, 6 avenue du Swing, L-4367 Belvaux, Luxembourg.
(5)Department of Otolaryngology Head & Neck Surgery, The Ninth People's Hospital
& Ear Institute, School of Medicine & Shanghai Key Laboratory of Translational
Medicine on Ear and Nose Diseases, Shanghai Jiao Tong University, Shanghai,
China.
(6)Department of Molecular Biology, Max Planck Institute for Developmental
Biology, Tübingen, Germany.
(7)The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty
of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel.
(8)Department of Biochemistry & Molecular Biology, George S. Wise Faculty of
Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel.
(9)Department of Biochemistry and Microbiology, Rutgers University, New
Brunswick, NJ 08901, USA.
(10)Roche Polska Sp. z o.o., Domaniewska 39B, 02-672 Warsaw, Poland.
(11)Garvan Institute of Medical Research, Sydney, Australia.
(12)Department of Data Sciences, Dana-Farber Cancer Institute, Boston, MA 02215,
USA.
(13)Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA.
(14)Broad Institute of MIT and Harvard, Boston, MA 02142, USA.
(15)HSWT (Hochschule Weihenstephan Triesdorf | University of Applied Sciences),
Department of Bioengineering Sciences, Am Hofgarten 10, 85354 Freising, Germany.
(16)Department of Pharmacological Sciences, Icahn School of Medicine at Mount
Sinai, New York, NY 10029, USA.
(17)BIPS, Poblacion Baco, Mindoro, Philippines.
(18)Quantitative and Computational Biology, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany.
(19)School of Biological Sciences, Seoul National University, Seoul, South
Korea.
(20)Artificial Intelligence Institute, Seoul National University, Seoul, South
Korea.
(21)Institute for Advanced Study (TUM-IAS), Lichtenbergstr. 2a, 85748
Garching/Munich, Germany.
(22)TUM School of Life Sciences Weihenstephan (WZW), Alte Akademie 8, Freising,
Germany. Proteins are essential to life, and understanding their structure can facilitate
a mechanistic understanding of their function. Through an enormous experimental
effort1-4, the structures of around 100,000 unique proteins have been
determined5, but this represents a small fraction of the billions of known
protein sequences6,7. Structural coverage is bottlenecked by the months to years
of painstaking effort required to determine a single protein structure. Accurate
computational approaches are needed to address this gap and to enable
large-scale structural bioinformatics. Predicting the three-dimensional
structure that a protein will adopt based solely on its amino acid sequence-the
structure prediction component of the 'protein folding problem'8-has been an
important open research problem for more than 50 years9. Despite recent
progress10-14, existing methods fall far short of atomic accuracy, especially
when no homologous structure is available. Here we provide the first
computational method that can regularly predict protein structures with atomic
accuracy even in cases in which no similar structure is known. We validated an
entirely redesigned version of our neural network-based model, AlphaFold, in the
challenging 14th Critical Assessment of protein Structure Prediction (CASP14)15,
demonstrating accuracy competitive with experimental structures in a majority of
cases and greatly outperforming other methods. Underpinning the latest version
of AlphaFold is a novel machine learning approach that incorporates physical and
biological knowledge about protein structure, leveraging multi-sequence
alignments, into the design of the deep learning algorithm. |
Which proteins does p110α interact with? | p110α interacts with p85α and RAS proteins. | Phosphoinositide 3-kinase (PI3K) mediates insulin actions by relaying signals
from insulin receptors (IRs) to downstream targets. The p110α catalytic subunit
of class IA PI3K is the primary insulin-responsive PI3K implicated in insulin
signaling. We demonstrate here a new mode of spatial regulation for the p110α
subunit of PI3K by PAQR3 that is exclusively localized in the Golgi apparatus.
PAQR3 interacts with p110α, and the intracellular targeting of p110α to the
Golgi apparatus is reduced by PAQR3 downregulation and increased by PAQR3
overexpression. Insulin-stimulated PI3K activity and phosphoinositide
(3,4,5)-triphosphate production are enhanced by Paqr3 deletion and reduced by
PAQR3 overexpression in hepatocytes. Deletion of Paqr3 enhances
insulin-stimulated phosphorylation of AKT and glycogen synthase kinase 3β, but
not phosphorylation of IR and IR substrate-1 (IRS-1), in hepatocytes, mouse
liver, and skeletal muscle. Insulin-stimulated GLUT4 translocation to the plasma
membrane and glucose uptake are enhanced by Paqr3 ablation. Furthermore, PAQR3
interacts with the domain of p110α involved in its binding with p85, the
regulatory subunit of PI3K. Overexpression of PAQR3 dose-dependently reduces the
interaction of p85α with p110α. Thus, PAQR3 negatively regulates insulin
signaling by shunting cytosolic p110α to the Golgi apparatus while competing
with p85 subunit in forming a PI3K complex with p110α. Phosphatidylinositol 3-kinase (PI3K) α is a heterodimeric lipid kinase that
catalyzes the conversion of phosphoinositol-4,5-bisphosphate to
phosphoinositol-3,4,5-trisphosphate. The PI3Kα signaling pathway plays an
important role in cell growth, proliferation, and survival. This pathway is
activated in numerous cancers, where the PI3KCA gene, which encodes for the
p110α PI3Kα subunit, is mutated. Its mutation often results in gain of enzymatic
activity; however, the mechanism of activation by oncogenic mutations remains
unknown. Here, using computational methods, we show that oncogenic mutations
that are far from the catalytic site and increase the enzymatic affinity
destabilize the p110α-p85α dimer. By affecting the dynamics of the protein,
these mutations favor the conformations that reduce the autoinhibitory effect of
the p85α nSH2 domain. For example, we determined that, in all of the mutants,
the nSH2 domain shows increased positional heterogeneity as compared with the
wild-type, as demonstrated by changes in the fluctuation profiles computed by
normal mode analysis of coarse-grained elastic network models. Analysis of the
interdomain interactions of the wild-type and mutants at the p110α-p85α
interface obtained with molecular dynamics simulations suggest that all of the
tumor-associated mutations effectively weaken the interactions between p110α and
p85α by disrupting key stabilizing interactions. These findings have important
implications for understanding how oncogenic mutations change the conformational
multiplicity of PI3Kα and lead to increased enzymatic activity. This mechanism
may apply to other enzymes and/or macromolecular complexes that play a key role
in cell signaling. Glutathione S-transferases P1 (GSTP1) is a phase II detoxifying enzyme and
increased expression of GSTP1 has been linked with acquired resistance to
anti-cancer drugs. However, most anticancer drugs are not good substrates for
GSTP1, suggesting that the contribution of GSTP1 to drug resistances might not
be dependent on its capacity to detoxify chemicals or drugs. In the current
study, we found a novel mechanism by which GSTP1 protects human breast cancer
cells from adriamycin (ADR)-induced cell death and contributes to the drug
resistance. GSTP1 protein level is very low in human breast cancer cell line
MCF-7 but is high in ADR-resistant MCF-7/ADR cells. Under ADR treatment,
MCF-7/ADR cells showed a higher autophagy level than MCF-7 cells. Overexpression
of GSTP1 in MCF-7 cells by using the DNA transfection vector enhanced autophagy
and down-regulation of GSTP1 through RNA interference in MCF-7/ADR cells
decreased autophagy. When autophagy was prevented, GSTP1-induced ADR resistance
reduced. We found that GSTP1 enhanced autophagy level in MCF-7 cells through
interacting with p110α subunit of phosphatidylinositol-3-kinase (PI3K) and then
inhibited PI3K/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR)
activity. Proline123, leucine160, and glutamine163, which located in C terminal
of GSTP1, are essential for GSTP1 to interact with p110α, and the following
autophagy and drug resistance regulation. Taken together, our findings
demonstrate that high level of GSTP1 maintains resistance of breast cancer cells
to ADR through promoting autophagy. These new molecular insights provide an
important contribution to our better understanding the effect of GSTP1 on the
resistance of tumors to chemotherapy. Attribution of specific roles to the two ubiquitously expressed PI 3-kinase
(PI3K) isoforms p110α and p110β in biological functions they have been
implicated, such as in insulin signalling, has been challenging. While p110α has
been demonstrated to be the principal isoform activated downstream of the
insulin receptor, several studies have provided evidence for a role of p110β.
Here we have used isoform-selective inhibitors to estimate the relative
contribution of each of these isoforms in insulin signalling in adipocytes,
which are a cell type with essential roles in regulation of metabolism at the
systemic level. Consistent with previous genetic and pharmacological studies, we
found that p110α is the principal isoform activated downstream of the insulin
receptor under physiological conditions. p110α interaction with Ras enhanced the
strength of p110α activation by insulin. However, this interaction did not
account for the selectivity for p110α over p110β in insulin signalling. We also
demonstrate that p110α is the principal isoform activated downstream of the
β-adrenergic receptor (β-AR), another important signalling pathway in metabolic
regulation, through a mechanism involving activation of the cAMP effector
molecule EPAC1. This study offers further insights in the role of PI3K isoforms
in the regulation of energy metabolism with implications for the therapeutic
application of selective inhibitors of these isoforms. |
Which is the protein-membrane interface of the Cholesterol-regulated Start protein 4 protein (STARD4)? | L124 is the protein-membrane interface of the Cholesterol-regulated Start protein 4 protein (STARD4). | The steroidogenic acute regulatory protein-related lipid transfer (START) domain
family is defined by a conserved 210-amino acid sequence that folds into an α/β
helix-grip structure. Members of this protein family bind a variety of ligands,
including cholesterol, phospholipids, sphingolipids, and bile acids, with
putative roles in nonvesicular lipid transport, metabolism, and cell signaling.
Among the soluble START proteins, STARD4 is expressed in most tissues and has
previously been shown to transfer sterol, but the molecular mechanisms of
membrane interaction and sterol binding remain unclear. In this work, we use
biochemical techniques to characterize regions of STARD4 and determine their
role in membrane interaction and sterol binding. Our results show that STARD4
interacts with anionic membranes through a surface-exposed basic patch and that
introducing a mutation (L124D) into the Omega-1 (Ω1) loop, which covers the
sterol binding pocket, attenuates sterol transfer activity. To gain insight into
the attenuating mechanism of the L124D mutation, we conducted structural and
biophysical studies of wild-type and L124D STARD4. These studies show that the
L124D mutation reduces the conformational flexibility of the protein, resulting
in a diminished level of membrane interaction and sterol transfer. These studies
also reveal that the C-terminal α-helix, and not the Ω1 loop, partitions into
the membrane bilayer. On the basis of these observations, we propose a model of
STARD4 membrane interaction and sterol binding and release that requires dynamic
movement of both the Ω1 loop and membrane insertion of the C-terminal α-helix. |
What causes the "worst headache" of a patient's life? | This is a classic description of a subarachnoid hemorrhage (SAH). The gold standard for the diagnostic evaluation of a SAH remains non-contrast head computed tomography (CT) followed by lumbar puncture if the CT is negative. | STUDY OBJECTIVE: This study investigated the hypothesis that modern computed
tomographic (CT) imaging is sufficient to exclude subarachnoid hemorrhage (SAH)
in patients with severe headache.
METHODS: All 38,730 adult patients who presented to Hermann Hospital in Houston,
Texas, during a 16-month period were prospectively screened to detect those with
"the worst headache of my life." Two neuroradiologists blinded to the study
hypothesis interpreted the CT scans. Patients with negative scans underwent
comprehensive cerebrospinal fluid (CSF) analysis including cell count in first
and last tubes, visual and spectrophotometric detection of xanthochromia, and
CSF D-dimer assay.
RESULTS: A chief complaint of headache was elicited in 455 patients, and 107 of
these had "worst headache" and were enrolled in the study. CT-confirmed SAH was
found in 18 of the 107 (17%). Only 2 patients (2.5%, 95% confidence interval,
.3% to 8.8%) had SAH detected by CSF analysis among those with negative CT
imaging result. CSF spectrophotometric detection was the most sensitive test for
blood. Three patients with less than 6 red blood cells in tube 1 had positive
spectrophotometric results, but in all 3, tube 4 was negative on
spectrophotometric analysis, suggesting a high false-positive rate.
CONCLUSION: Modern CT imaging is sufficient to exclude 97.5% of SAH in patients
presenting to the ED with "worst headache" symptoms. BACKGROUND: Headache is the most common presenting symptom of subarachnoid
hemorrhage (SAH), ranging from mild headache to the "worst headache of my life".
As headache is often non-specific, patients may not seek immediate medical
attention, though prompt medical and surgical management is expected to improve
clinical outcomes. In this study, we explore the independent association between
duration from onset of symptoms to presentation at an emergency department (ED)
and clinical outcomes after SAH.
METHODS: Participants with a primary diagnosis of nontraumatic SAH were
identified from consecutive patients at 11 regional stroke centres participating
in the Registry of the Canadian Stroke Network (RCSN, 2003-2005). Hunt and Hess
score (H+H), and modified Rankin Scale (mRS) at discharge were collected on SAH
cases by trained nurse-abstractors. For analysis, patients were categorized into
patients with mild-moderate dependency (mRS 0-3) and those with severe
dependence or death (mRS 4-6) at hospital discharge. Multivariable regression
analyses were used to determine the association between 'time to presentation'
and clinical outcomes, independent of comorbidities.
RESULTS: Of 721 SAH patients included in the RCSN, 642 (89.0%) had the interval
between 'time last seen normal' and time of ED presentation recorded. Mean
duration from symptom onset to ED arrival was 27.04 hours (+/- 2.02). One
hundred and sixty-six patients (25.9%) presented to the ED more than 24 hours
after onset of symptoms. On multivariable analysis, there was no association
between time to presentation and severe disability or death at hospital
discharge (OR 1.0 [95% CI 0.95-1.01]); 30-day mortality (OR 1.0 [95% CI
0.91-1.02]; or six-month mortality (OR 1.0 [95% CI 1.0-1.02]). Increasing H+H
score and age were significantly associated with increased odds of death and
severe dependence at hospital discharge.
CONCLUSIONS: In this observational study, duration from symptom onset to
hospital presentation was not independently associated with death or severe
disability at hospital discharge following SAH. Age and H+H score were
independent predictors of clinical outcome after non-traumatic SAH. Aneurysmal subarachnoid hemorrhage (SAH) is a neurological emergency with high
risk of neurological decline and death. Although the presentation of a
thunderclap headache or the worst headache of a patient's life easily triggers
the evaluation for SAH, subtle presentations are still missed. The gold standard
for diagnostic evaluation of SAH remains noncontrast head computed tomography
(CT) followed by lumbar puncture if the CT is negative for SAH. Management of
patients with SAH follows standard resuscitation of critically ill patients with
the emphasis on reducing risks of rebleeding and avoiding secondary brain
injuries. |
Which are the types of cancer that c-Myc is associated with? | The types of cancer that c-Myc is associates with are breast cancer, non-small-cell lung cancer and pancreatic ductal adenocarcinoma. | The function of c-myc in physiology is only partially known. Its product has DNA
binding properties and plays a role in the control of proliferation and
differentiation. In general, increased c-myc expression leads to proliferation
and abolishment of differentiation. The involvement of c-myc in mouse
plasmacytomas and human Burkitt's lymphoma is well known: due to chromosomal
translocation c-myc comes under the influence of regulatory elements of
immunoglobulin genes, leading to increased expression of the gene and
proliferation of the cells. In man, the chromosomal translocations may occur
within the increased pool of (pre) B-cells due to Epstein Barr virus (EBV) and
malaria infection with subsequent immunosuppression. Apart from these early
(primary?) events in lymphomagenesis, c-myc is also often involved in tumour
progression, probably by a similar mechanism. Different types of c-myc
involvement are associated with specific types of lymphoma: there are
differences between endemic, sporadic and ileocecal Burkitt's lymphoma as well
as between those and primary extranodal large cell lymphoma and large cell
lymphoma which has progressed. These differences are associated with the
differentiation of the involved lymphoid cells and may point to the stage of
differentiation in which the oncogenic event occurred. Molecular and cell biologic studies of a large number of lung cancer cell lines
of all histologic types have revealed several mechanisms active in the
pathogenesis of these cells. Small cell lung cancer (also called "oat cell" lung
cancer) has a deletion involving chromosome region 3p(14-23) that is confirmed
by DNA restriction fragment length polymorphisms analysis (studies done in
collaboration with Dr. Susan Naylor). Several lung cancers of both small cell
and non-small cell type (including adeno- and squamous cell lung cancer) express
the proto-oncogenes c-, N-, or L-myc, and in some cases more than one of these
family members. N-myc appears restricted in its expression to the small cell
lung cancer type while c-myc and L-myc can be expressed in both small cell and
non-small cell lung cancers. Many lung cancers of all histologic types also
express large amounts of p53, which are not correlated with the amount or type
of myc gene product expressed. In small cell lung cancer, high levels of myc
gene expression are usually associated with gene amplification, and not
uncommonly there is rearrangement of some of the amplified copies. In non-small
cell lung cancer, expression without amplification or rearrangement of myc genes
is seen. In contrast, high level expression of p53 is not associated with gene
amplification in any lung cancer type. In addition, to these proto-oncogenes
acting at a presumed nuclear locus, there is increased expression of various ras
family members and the c-raf-1 proto-oncogene (in collaboration with Dr. Ulf
Rapp). Lung cancer cells in tissue culture can grow in medium without serum and
few or no other growth factors added. Thus, it appears that lung cancer cells
can produce their own growth factors which can act in an "autocrine" fashion.
The best characterized example of this is gastrin releasing peptide (GRP, also
called bombesin) produced by small cell lung cancer. In at least some small cell
lung cancers, interference with GRP action by specific monoclonal antibodies
results in inhibition of tumor cell growth in culture and in nude mouse
xenografts. Thus, constitutively expressed GRP gene may function as a cellular
oncogene under certain circumstances in small cell lung cancer. Based on these
observations we are proposing to test monoclonal anti-GRP antibodies in
patients. DNAs from 253 fresh human tumors of 38 different types were hybridized with 17
different oncogene probes. The analysis demonstrated unique associations between
amplification of specific oncogenes and specific types of tumors. In a large
number of cases it was determined that amplified oncogenes occurred in 10 to 20%
of tumors with the following specific associations: c-myc in adenocarcinomas,
squamous carcinomas and sarcomas but not hematologic maligcies; c-erbB2 in
adenocarcinomas, particularly breast cancers; c-erbB1 in squamous carcinomas;
N-myc in neuroblastomas. A small number of cases suggested other specific
associations: amplified c-myb in breast cancers; amplified c-ras-Ha and c-ras-Ki
in ovarian carcinomas. In addition, there was a correlation between
amplification of c-myc and the clinical stage of adenocarcinomas, and
amplification of c-erbB2 and the clinical stage and lymph node involvement of
breast cancers. c-MYC is a multifaceted protein that regulates cell proliferation,
differentiation and apoptosis. Its crucial role in diverse cancers has been
demonstrated in several studies. Here, we analysed the influence of the rare
c-MYC Asn11Ser polymorphism on familial breast cancer risk by performing a
case-control study with a Polish (cases n = 349; controls n = 441) and a German
(cases n = 356; controls n = 655) study population. All cases have been tested
negative for mutations in the BRCA1 and BRCA2 genes. A joint analysis of the
Polish and the German study population revealed a 54% increased risk for breast
cancer associated with the heterozygous Asn11Ser variant (OR = 1.54, 95% CI
1.05-2.26, p = 0.028). The breast cancer risk associated with this genotype
increases above the age of 50 years (OR = 2.24, 95% CI 1.20-4.21, p = 0.012).
The wild-type amino acid Asn of this polymorphism is located in the N-terminal
MYC transactivation domain and is highly conserved not only among most diverse
species but also in the N-MYC homologue. Due to the pivotal role of c-MYC in
diverse tumours, this variant might affect the genetic susceptibility of other
cancers as well. The MYC family of cellular oncogenes includes c-Myc, N-myc, and L-myc, which
encode transcriptional regulators involved in the control of cell proliferation
and death. Accordingly, these genes become aberrantly activated and expressed in
specific types of cancers. For example, c-Myc translocations occur frequently in
human B lymphoid tumors, while N-myc gene amplification is frequent in human
neuroblastomas. The observed association between aberrations in particular MYC
family genes and specific subsets of maligcies might reflect, at least in
part, tissue-specific differences in expression or function of a given MYC gene.
Since c-Myc and N-myc share substantial functional redundancy, another factor
that could influence tumor-specific gene activation would be mechanisms that
target aberrations (e.g., translocations) in a given MYC gene in a particular
tumor progenitor cell type. We have previously shown that mice deficient for the
DNA Ligase4 (Lig4) nonhomologous DNA end-joining factor and the p53 tumor
suppressor routinely develop progenitor (pro)-B cell lymphomas that harbor
translocations leading to c-Myc amplification. Here, we report that a modified
allele in which the c-Myc coding sequence is replaced by N-myc coding sequence
(NCR allele) competes well with the wild-type c-Myc allele as a target for
oncogenic translocations and amplifications in the Lig4/p53-deficient pro-B cell
lymphoma model. Tumor onset, type, and cytological aberrations are similar in
tumors harboring either the wild-type c-Myc gene or the NCR allele. Our results
support the notion that particular features of the c-Myc locus select it as a
preferential translocation/amplification target, compared to the endogenous
N-myc locus, in Lig4/p53-deficient pro-B cell lymphomas. The upregulation or mutation of C-MYC has been observed in gastric, colon,
breast, and lung tumors and in Burkitt's lymphoma. However, little is known
about the role C-MYC plays in gastric adenocarcinoma. In the present study, we
intended to investigate the influence of C-MYC on the growth, proliferation,
apoptosis, invasion, and cell cycle of the gastric cancer cell line SGC7901 and
the gastric cell line HFE145. C-MYC cDNA was subcloned into a constitutive
vector PCDNA3.1 followed by transfection in normal gastric cell line HFE145 by
using liposome. Then stable transfectants were selected and appraised. Specific
inhibition of C-MYC was achieved using a vector-based siRNA system which was
transfected in gastric cancer cell line SGC7901. The apoptosis and cell cycles
of these clones were analyzed by using flow cytometric assay. The growth and
proliferation were analyzed by cell growth curves and colony-forming assay,
respectively. The invasion of these clones was analyzed by using cell migration
assay. The C-MYC stable expression clones (HFE-Myc) and C-MYC RNAi cells
(SGC-MR) were detected and compared with their control groups, respectively.
HFE-Myc grew faster than HFE145 and HFE-PC (HFE145 transfected with PCDNA3.1
vector). SGC-MR1, 2 grew slower than SGC7901 and SGC-MS1, 2 (SGC7901 transfected
with scrambled control duplexes). The cell counts of HFE-Myc in the third,
fourth, fifth, sixth, and seventh days were significantly more than those of
control groups (P < 0.05). Those of SGC-MR1, 2 in the fourth, fifth, sixth, and
seventh days were significantly fewer than those of control groups (P < 0.05).
Cell cycle analysis showed that proportions of HFE-Myc and SGC-MR cells in G0-G1
and G2-M were different significantly with their control groups, respectively (P
< 0.05). The apoptosis rate of HFE-Myc was significantly higher than those of
control groups (P < 0.05). Results of colony-forming assay showed that the
colony formation rate of HFE-Myc was higher than those of control groups;
otherwise, the rate of SGC-MR was lower than those of their control groups (P <
0.05). The results of cell migration assay showed that there were no significant
differences between experimental groups and control groups (P > 0.05). In
conclusion, C-MYC can promote the growth and proliferation of normal gastric
cells, and knockdown of C-MYC can restrain the growth and proliferation of
gastric cancer cells. It can induce cell apoptosis and help tumor cell maintain
maligt phenotype. But it can have not a detectable influence on the ability
of invasion of gastric cancer cells. CONTEXT: c-Myc plays a key role in glioma cancer stem cell maintece. A drug
delivery system, oparticles loading plasmid DNAs inserted with siRNA
fragments targeting c-Myc gene (NPs-c-Myc-siRNA-pDNAs), for the treatment of
glioma, has not previously been reported.
OBJECTIVE: NPs-c-Myc-siRNA-pDNAs were prepared and evaluated in vitro.
MATERIALS AND METHODS: Three kinds of c-Myc-siRNA fragments were separately
synthesized and linked with empty siRNA expression vectors in the mole ratio of
3:1 by T4 DNA ligase. The linked products were then separately transfected into
Escherichia coli. DH5α followed by extraction with Endofree plasmid Mega kit
(Qiagen, Hilden, Germany) obtained c-Myc-siRNA-pDNAs. Finally, the recombit
c-Myc-siRNA3-pDNAs, generating the highest transfection efficiency and the
greatest apoptotic ability, were chosen for encapsulation into NPs by the
double-emulsion solvent-evaporation procedure, followed by stability,
transfection efficiency, as well as qualitative and quantitative apoptosis
evaluation.
RESULTS: NPs-c-Myc-siRNA3-pDNAs were obtained with spherical shape in uniform
size below 150 nm, with the zeta potential about -18 mV, the encapsulation
efficiency and loading capacity as 76.3 ± 5.4% and 1.91 ± 0.06%, respectively.
The stability results showed that c-Myc-siRNA3-pDNAs remained structurally and
functionally stable after encapsulated into NPs, and NPs could prevent the
loaded c-Myc-siRNA3-pDNAs from DNase degradation. The transfection efficiency of
NPs-c-Myc-siRNA3-pDNAs was proven to be positive. Furthermore,
NPs-c-Myc-siRNA3-pDNAs produced significant apoptosis with the apoptotic rate at
24.77 ± 5.39% and early apoptosis cells observed.
DISCUSSION AND CONCLUSION:
Methoxy-poly-(ethylene-glycol)-poly-(lactide-co-glycolide) oparticles
(MPEG-PLGA-NPs) are potential delivery carriers for c-Myc-siRNA3-pDNAs. BACKGROUND: Pancreatic ductal adenocarcinoma (PDA) is frequently driven by
oncogenic KRAS(KRAS*) mutations. We developed a mouse model of KRAS*-induced PDA
and, based on genetic results demonstrating that KRAS* tumorigenicity depends on
Myc activity, we evaluated the therapeutic potential of an orally administered
anti-Myc drug.
METHODS: We tested the efficacy of Mycro3, a small-molecule inhibitor of Myc-Max
dimerization, in the treatment of mouse PDA (n = 9) and also of xenografts of
human pancreatic cancer cell lines (NOD/SCID mice, n = 3-12). Tumor responses to
the drug were evaluated by PET/CT imaging, and histological,
immunohistochemical, molecular and microarray analyses. The Student's t test was
used for differences between groups. All statistical tests were two-sided.
RESULTS: Transgenic overexpression of KRAS* in the pancreas resulted in
pancreatic intraepithelial neoplasia in two-week old mice, which developed
invasive PDA a week later and became moribund at one month. However, this
aggressive form of pancreatic tumorigenesis was effectively prevented by genetic
ablation of Myc specifically in the pancreas. We then treated moribund,
PDA-bearing mice daily with the Mycro3 Myc-inhibitor. The mice survived until
killed at two months. PET/CT image analysis (n = 5) demonstrated marked
shrinkage of PDA, while immunohistochemical analyses showed an increase in
cancer cell apoptosis and reduction in cell proliferation (treated/untreated
proliferation index ratio: 0.29, P < .001, n = 3, each group). Tumor growth was
also drastically attenuated in Mycro3-treated NOD/SCID mice (n = 12) carrying
orthotopic or heterotopic xenografts of human pancreatic cancer cells (eg, mean
tumor weight ± SD of treated heterotopic xenografts vs vehicle-treated controls:
15.2±5.8 mg vs 230.2±43.9 mg, P < .001).
CONCLUSION: These results provide strong justification for eventual clinical
evaluation of anti-Myc drugs as potential chemotherapeutic agents for the
treatment of PDA. BACKGROUND: MYC is amplified in approximately 15% of breast cancers (BCs) and is
associated with poor outcome. c-MYC protein is multi-faceted and participates in
many aspects of cellular function and is linked with therapeutic response in
BCs. We hypothesised that the functional role of c-MYC differs between molecular
subtypes of BCs.
METHODS: We therefore investigated the correlation between c-MYC protein
expression and other proteins involved in different cellular functions together
with clinicopathological parameters, patients' outcome and treatments in a large
early-stage molecularly characterised series of primary invasive BCs (n=1106)
using immunohistochemistry. The METABRIC BC cohort (n=1980) was evaluated for
MYC mRNA expression and a systems biology approach utilised to identify genes
associated with MYC in the different BC molecular subtypes.
RESULTS: High MYC and c-MYC expression was significantly associated with poor
prognostic factors, including grade and basal-like BCs. In luminal A tumours,
c-MYC was associated with ATM (P=0.005), Cyclin B1 (P=0.002), PIK3CA (P=0.009)
and Ki67 (P<0.001). In contrast, in basal-like tumours, c-MYC showed positive
association with Cyclin E (P=0.003) and p16 (P=0.042) expression only. c-MYC was
an independent predictor of a shorter distant metastases-free survival in
luminal A LN+ tumours treated with endocrine therapy (ET; P=0.013). In luminal
tumours treated with ET, MYC mRNA expression was associated with BC-specific
survival (P=0.001). In ER-positive tumours, MYC was associated with expression
of translational genes while in ER-negative tumours it was associated with
upregulation of glucose metabolism genes.
CONCLUSIONS: c-MYC function is associated with specific molecular subtypes of
BCs and its overexpression confers resistance to ET. The diverse mechanisms of
c-MYC function in the different molecular classes of BCs warrants further
investigation particularly as potential therapeutic targets. Previously, we cloned a new gene termed 'tongue cancer resistance-associated
protein 1' (TCRP1), which modulates tumorigenesis, enhances cisplatin (cDDP)
resistance in cancers, and may be a potential target for reversing drug
resistance. However, the mechanisms for regulating TCRP1 expression remain
unclear. Herein, we combined bioinformatics analysis with luciferase reporter
assay and ChIP assay to determine that c-Myc could directly bind to TCRP1
promoter to upregulate its expression. TCRP1 upregulation in multidrug resistant
tongue cancer cells (Tca8113/PYM) and cisplatin-resistant A549 lung cancer cells
(A549/DDP) was accompanied by c-Myc upregulation, compared to respective
parental cells. In tongue and lung cancer cells, siRNA-mediated knockdown of
c-Myc led to decrease TCRP1 expression, whereas overexpression c-Myc did the
opposite. Moreover, TCRP1 knockdown attenuated chemoresistance resulting from
c-Myc overexpression, but TCRP1 overexpression impaired the effect of c-Myc
knockdown on chemosensitivity. Additionally, in both human tongue and lung
cancer tissues, c-Myc protein expression positively correlated with TCRP1
protein expression and these protein levels were associated with worse prognosis
for patients. Combined, these findings suggest that c-Myc could
transcriptionally regulate TCRP1 in cell lines and clinical samples and
identified the c-Myc-TCRP1 axis as a negative biomarker of prognosis in tongue
and lung cancers. It has been reported that miR-376a is involved in the formation and progression
of several types of cancer. However, the expression and function of miR-376a is
still unknown in non-small cell lung carcinomas (NSCLC). In this study, the
expression of miR-376a in NSCLC tissues and cell lines were examined by
real-time PCR, the effects of miR-376a on cell proliferation, apoptosis and
invasion were evaluated in vitro. Luciferase reporter assay was performed to
identify the targets of miR-376a. The results showed that miR-376a was
significantly downregulated in NSCLC tissues and cell lines. Restoration of
miR-376a in NSCLC cell line A549 significantly inhibited cell proliferation,
increased cell apoptosis and suppressed cell invasion, compared with
control-transfected A549 cells. Luciferase reporter assay showed that c-Myc, an
oncogene that regulating cell survival, angiogenesis and metastasis, was a
direct target of miR-376a. Over-expression of miR-376a decreased the mRNA and
protein levels of c-Myc in A549 cells. In addition, upregulation of c-Myc
inhibited miR-376a-induced inhibition of cell proliferation and invasion in A549
cells. Therefore, our results indicate a tumor suppressor role of miR-376a in
NSCLC by targeting c-Myc. miR-376a may be a promising therapeutic target for
NSCLC. The transcription factor gene MYC is important in breast cancer, and its mRNA is
maintained at a high level even in the absence of gene amplification. The
mechanism(s) underlying increased MYC mRNA expression is unknown. Here, we
demonstrate that MYC mRNA was stabilized upon estrogen stimulation of estrogen
receptor-positive breast cancer cells via SRC-dependent effects on a recently
described RNA-binding protein, IMP1 with an N-terminal deletion (ΔN-IMP1). We
also show that loss of the tumor suppressor p53 increased MYC mRNA levels even
in the absence of estrogen stimulation. However, in cells with wild-type p53,
SRC acted to overcome p53-mediated inhibition of estrogen-stimulated cell cycle
entry and progression. SRC thus promotes cell proliferation in two ways: by
stabilizing MYC mRNA and by inhibiting p53 function. Since estrogen
receptor-positive breast cancers typically express wild-type p53, these studies
establish a rationale for p53 status to be predictive for effective SRC
inhibitor treatment in this subtype of breast cancer. Pancreatic adenocarcinoma is a highly maligt cancer that often involves a
deregulation of c-Myc. It has been shown that c-Myc plays a pivotal role in the
regulation of a variety of physiological processes and is involved in early
neoplastic development, resulting in poor progression. Hence, suppression of
c-Myc overexpression is a potential strategy for pancreatic cancer therapy.
CUDC-907 is a novel dual-acting inhibitor of phosphoinositide 3-kinase (PI3K)
and histone deacetylase (HDAC). It has shown potential efficiency in patients
with lymphoma, multiple myeloma, or thyroid cancer, as well as in solid tumors
with c-Myc alterations, but the evidence is lacking for how CUDC-907 regulates
c-Myc. In this study, we investigated the effect of CUDC-907 on human pancreatic
cancer cells in vitro and in vivo. Our results showed that CUDC-907 potently
inhibited the proliferation of 9 pancreatic cancer cell lines in vitro with IC50
values ranging from 6.7 to 54.5 nM. Furthermore, we revealed the antitumor
mechanism of CUDC-907 in Aspc-1, PANC-1, and Capan-1 pancreatic cancer cells: it
suppressed the HDAC6 subunit, thus downregulating c-Myc protein levels, which
was a mode of action distinct from the existing mechanisms. Consistently, the
extraordinary antitumor activity of CUDC-907 accompanied by downregulation of
c-Myc and Ki67 expression in tumor tissue was observed in a human pancreatic
cancer Aspc-1 xenograft nude mouse model in vivo. Our results suggest that
CUDC-907 can be a valuable therapeutic option for treating pancreatic
adenocarcinoma. Background: c-Myc is overexpressed in different types of cancer, including
thyroid cancer, and has been considered undruggable. There is evidence showing
that MLN8237, a type of aurora A kinase (AURKA) inhibitor, destabilizes c-Myc
proteins in liver cancer cells through disruption of the c-Myc/AURKA complex.
However, the role of MLN8237 in thyroid cancer remains largely unclear. The aims
of this study were to test the therapeutic potential of MLN8237 in thyroid
cancer, and to analyze determit factors affecting the response of thyroid
cancer cells to MLN8237 and clarify the corresponding mechanism. Methods: The
phenotypic effects of MLN8237 in thyroid cancer cells were evaluated through a
series of in vitro and in vivo experiments, and the mechanism of c-Myc affecting
MLN8237 response were explored using Western blot, ubiquitination, and
cycloheximide chase assays. Results: The data show that the levels of c-Myc
protein were strongly associated with MLN8237 cellular response in thyroid
cancer cells. Only the cells with high c-Myc expression exhibited growth
inhibition upon MLN8237 treatment. However, MLN8237 barely affected the growth
of those with low c-Myc expression. Mechanistically, MLN8237 dramatically
promoted proteasomal degradation of c-Myc proteins through disruption of the
c-Myc/AURKA complex in the cells with high c-Myc expression. A similar antitumor
activity of MLN8237 was also found in xenograft tumor models. Conclusions: The
data demonstrate that c-Myc is a major determit for MLN8237 responsiveness in
thyroid cancer cells. Thus, indirectly targeting c-Myc by MLN8237 may be an
effective strategy for thyroid cancer overexpressing c-Myc. Aim: To investigate whether plasma C-MYC level could be an indicator in clinical
progression of breast cancer. Materials & methods: Plasma level of C-MYC
expression was detected by quantitative real time PCR and the level of c-myc
protein in breast cancer tissues was detected by immunohistochemistry. The
expression level of C-MYC mRNA in supernatant of cancer cells culture was
measured compared with the nonbreast cancer cells. Results: Plasma C-MYC level
was significantly higher in patients with breast cancer than that in the
controls, which associated with clinical stages, lymph node status, etc.
Receiver operating characteristic curve analysis showed the sensitivity and
specificity of plasma C-MYC level for diagnosis of breast cancer were 63.6 and
81.8%, respectively. The expression of c-myc protein in breast cancer tissues
was associated with plasma C-MYC level, even C-MYC level in supernatant of
cancer cells was elevated. Conclusion: Plasma C-MYC level might be a potential
indicator in progression of breast cancer. |
Which pathways are involved in cellular senescence? | Cellular senescence requires signal transduction, and the two most important signaling pathways are the P16Ink4a/Rb (retinoblastoma protein) pathway and the P19Arf/P53/P21Cip1 pathway, which interact but independently regulate the process of the cells cycle. | Cellular senescence is a program activated by normal cells in response to
various types of stress. These include telomere uncapping, DNA damage, oxidative
stress, oncogene activity and others. Senescence can occur following a period of
cellular proliferation or in a rapid manner in response to acute stress. Once
cells have entered senescence, they cease to divide and undergo a series of
dramatic morphologic and metabolic changes. Cellular senescence is thought to
play an important role in tumor suppression and to contribute to organismal
aging, but a detailed description of its physiologic occurrence in vivo is
lacking. Recent studies have provided important insights regarding the manner by
which different stresses and stimuli activate the signaling pathways leading to
senescence. These studies reveal that a population of growing cells may suffer
from a combination of different physiologic stresses acting simultaneously. The
signaling pathways activated by these stresses are funneled to the p53 and Rb
proteins, whose combined levels of activity determine whether cells enter
senescence. Here we review recent advances in our understanding of the stimuli
that trigger senescence, the molecular pathways activated by these stimuli, and
the manner by which these signals determine the entry of a population of cells
into senescence. Cellular senescence is a stable cell cycle arrest that can be triggered in
normal cells in response to various intrinsic and extrinsic stimuli, as well as
developmental signals. Senescence is considered to be a highly dynamic,
multi-step process, during which the properties of senescent cells continuously
evolve and diversify in a context dependent manner. It is associated with
multiple cellular and molecular changes and distinct phenotypic alterations,
including a stable proliferation arrest unresponsive to mitogenic stimuli.
Senescent cells remain viable, have alterations in metabolic activity and
undergo dramatic changes in gene expression and develop a complex
senescence-associated secretory phenotype. Cellular senescence can compromise
tissue repair and regeneration, thereby contributing toward aging. Removal of
senescent cells can attenuate age-related tissue dysfunction and extend health
span. Senescence can also act as a potent anti-tumor mechanism, by preventing
proliferation of potentially cancerous cells. It is a cellular program which
acts as a double-edged sword, with both beneficial and detrimental effects on
the health of the organism, and considered to be an example of evolutionary
antagonistic pleiotropy. Activation of the p53/p21WAF1/CIP1 and p16INK4A/pRB
tumor suppressor pathways play a central role in regulating senescence. Several
other pathways have recently been implicated in mediating senescence and the
senescent phenotype. Herein we review the molecular mechanisms that underlie
cellular senescence and the senescence associated growth arrest with a
particular focus on why cells stop dividing, the stability of the growth arrest,
the hypersecretory phenotype and how the different pathways are all integrated. |
Which disease phenotype has the worst prognosis in Duchenne Muscular Dystrophy? | A strong association between the risk of cognitive disability and the involvement of groups of DMD isoforms was found. In particular, improvements in the correlation of FSIQ with mutation location were identified when a new classification system for mutations affecting the Dp140 isoform was implemented. | The clinical course and prognosis of Duchenne muscular dystrophy (DMD) was
compared in patients with deletions of the gene for dystrophin (cDMD) and those
without such deletions. A total of 24 patients was followed for at least 2 yrs.
At age 12 the rating of the activities of daily life (ADL) and disease stage
were less favorable in those patients with deletions of the gene for cDMD. At
age 14, no difference in ADL and disease stage was observed between the two
groups. The percent vital capacity was lower in those patients with the cDMD
deficit. When the prognosis was evaluated by multivariate analysis of the data
obtained at age 12, the percent of patients predicted as dying before the age of
20 was 40% for those without the cDMD deficit but 76% for those who were cDMD
defective. None of the cDMD defective patients lived longer than 20 yrs, whereas
5 of 14 patients without the cDND deficit survived longer than 20 yrs. Disorders
such as cardiac and respiratory failure were also seen more frequently in the
cDND defective patients. These results suggest that patients with Duchenne
muscular dystrophy with defective cDMD have more severe disease than those
without cDMD deficit. About 60% of both Duchenne's muscular dystrophy (DMD) and Becker's muscular
dystrophy (BMD) is due to deletions of dystrophin gene. For cases with deletion
mutations the "reading frame" hypothesis predicts that deletions which result in
disruption of the translation reading frame prevent production of stable protein
and are associated with DMD. In contrast, intragenic deletions that involve
exons encoding an integral number of triplet codons maintain proper reading
frame. The resulting abnormal proteins are stable and partially functional,
resulting in a milder and more variable BMD phenotype. To test the validity of
this theory,we analyzed 40 patients-19 independent deletions at the DMD/BMD
locus. Clinical/molecular correlations based on the altera-tions of the reading
frame were valid in 69.2% of cases. After exclusion of: --2 patients with del
3-6 (with no consistent clinical expression); --1 DMD patient with large
in-frame deletion; --2 patients that were too young to be classified; --4
patients in whom it was impossible to identify the extent of deletion (del 47
and del 44-45), the correlation between deletion and clinical severity was as
predicted in 92.4% of cases. The present data should be useful in establishing
the prognosis in individual patients even in sporadic cases with no affected
relatives. BACKGROUND: A significant component of the variation in cognitive disability
that is observed in Duchenne muscular dystrophy (DMD) is known to be under
genetic regulation. In this study we report correlations between standardised
measures of intelligence and mutational class, mutation size, mutation location
and the involvement of dystrophin isoforms.
METHODS AND RESULTS: Sixty two male subjects were recruited as part of a study
of the cognitive spectrum in boys with DMD conducted at the Sydney Children's
Hospital (SCH). All 62 children received neuropsychological testing from a
single clinical psychologist and had a defined dystrophin gene (DMD) mutation;
including DMD gene deletions, duplications and DNA point mutations. Full Scale
Intelligence Quotients (FSIQ) in unrelated subjects with the same mutation were
found to be highly correlated (r = 0.83, p = 0.0008), in contrast to results in
previous publications. In 58 cases (94%) it was possible to definitively assign
a mutation as affecting one or more dystrophin isoforms. A strong association
between the risk of cognitive disability and the involvement of groups of DMD
isoforms was found. In particular, improvements in the correlation of FSIQ with
mutation location were identified when a new classification system for mutations
affecting the Dp140 isoform was implemented.
SIGNIFICANCE: These data represent one of the largest studies of FSIQ and
mutational data in DMD patients and is among the first to report on a DMD cohort
which has had both comprehensive mutational analysis and FSIQ testing through a
single referral centre. The correlation between FSIQ results with the location
of the dystrophin gene mutation suggests that the risk of cognitive deficit is a
result of the cumulative loss of central nervous system (CNS) expressed
dystrophin isoforms, and that correct classification of isoform involvement
results in improved estimates of risk. OBJECTIVE: Duchenne muscular dystrophy (DMD) is the most common single-gene
lethal disorder. Substantial patient-patient variability in disease onset and
progression and response to glucocorticoids is seen, suggesting genetic or
environmental modifiers.
METHODS: Two DMD cohorts were used as test and validation groups to define
genetic modifiers: a Padova longitudinal cohort (n = 106) and the Cooperative
International Neuromuscular Research Group (CINRG) cross-sectional natural
history cohort (n = 156). Single nucleotide polymorphisms to be genotyped were
selected from mRNA profiling in patients with severe vs mild DMD, and
genome-wide association studies in metabolism and polymorphisms influencing
muscle phenotypes in normal volunteers were studied.
RESULTS: Effects on both disease progression and response to glucocorticoids
were observed with polymorphism rs28357094 in the gene promoter of SPP1
(osteopontin). The G allele (domit model; 35% of subjects) was associated
with more rapid progression (Padova cohort log rank p = 0.003), and 12%-19% less
grip strength (CINRG cohort p = 0.0003).
CONCLUSIONS: Osteopontin genotype is a genetic modifier of disease severity in
Duchenne dystrophy. Inclusion of genotype data as a covariate or in inclusion
criteria in DMD clinical trials would reduce intersubject variance, and increase
sensitivity of the trials, particularly in older subjects. BACKGROUND: Duchenne muscular dystrophy (DMD) is a fatal progressive
muscle-wasting disease caused by mutations in the DMD gene. Dilated
cardiomyopathy is the leading cause of death in DMD; therefore, further
understanding of this complication is essential to reduce morbidity and
mortality.
METHODS: A common null variant (R577X) in the ACTN3 gene, which encodes
α-actinin-3, has been studied in association with muscle function in healthy
individuals; however it has not yet been examined in relationship to the cardiac
phenotype in DMD. In this study, we determined the ACTN3 genotype in 163
patients with DMD and examined the correlation between ACTN3 genotypes and
echocardiographic findings in 77 of the 163 patients.
RESULTS: The genotypes 577RR(RR), 577RX(RX) and 577XX(XX) were identified in 13
(17%), 44 (57%) and 20 (26%) of 77 patients, respectively. We estimated cardiac
involvement-free survival rate analyses using Kaplan-Meier curves. Remarkably,
the left ventricular dilation (> 55 mm)-free survival rate was significantly
lower in patients with the XX null genotype (P < 0.01). The XX null genotype
showed a higher risk for LV dilation (hazard ratio 9.04).
CONCLUSIONS: This study revealed that the ACTN3 XX null genotype was associated
with a lower left ventricular dilation-free survival rate in patients with DMD.
These results suggest that the ACTN3 genotype should be determined at the time
of diagnosis of DMD to improve patients' cardiac outcomes. Neuromuscular diseases (NMD) encompass a broad spectrum of diseases with
variable type of cardiac involvement and there is lack of clinical data on
Cardiovascular Magnetic Resoce (CMR) phenotypes or even prognostic value of
CMR in NMD. We explored the diagnostic and prognostic value of CMR in
NMD-related cardiomyopathies. The study included retrospective analysis of a
cohort of 111 patients with various forms of NMD; mitochondrial: n = 14,
Friedreich's ataxia (FA): n = 27, myotonic dystrophy: n = 27, Becker/Duchenne's
muscular dystrophy (BMD/DMD): n = 15, Duchenne's carriers: n = 6, other: n = 22.
Biventricular volumes and function and myocardial late gadolinium enhancement
(LGE) pattern and extent were assessed by CMR. Patients were followed-up for the
composite clinical endpoint of death, heart failure development or need for
permanent pacemaker/intracardiac defibrillator. The major NMD subtypes, i.e. FA,
mitochondrial, BMD/DMD, and myotonic dystrophy had significant differences in
the incidence of LGE (56%, 21%, 62% & 30% respectively, chi2 = 9.86, p = 0.042)
and type of cardiomyopathy phenotype (chi2 = 13.8, p = 0.008), extent/pattern
(p = 0.006) and progression rate of LGE (p = 0.006). In survival analysis the
composite clinical endpoint differed significantly between NMD subtypes
(p = 0.031), while the subgroup with LGE + and LVEF < 50% had the worst
prognosis (Log-rank p = 0.0034). We present data from a unique cohort of NMD
patients and provide evidence on the incidence, patterns, and the prognostic
value of LGE in NMD-related cardiomyopathy. LGE is variably present in NMD
subtypes and correlates with LV remodelling, dysfunction, and clinical outcomes
in patients with NMD. |
What links developmental pathways to ALS? | A direct link between developmental pathways and ALS is not described. However, cytoskeletal proteins such as KIF5A are implicated in ALS, and the cytoskeletal protein N-cadherin is involved in plasticity of the cerebral cortex. Development depends on connections of the sympathetic nervous system, involving mechanisms such as axon growth, neuron survival, and dendrite growth. BACE1, which is involved in Alzheimer's disease, is also implicated in axonal regeneration. | Modeling amyotrophic lateral sclerosis (ALS) with human induced pluripotent stem
cells (iPSCs) aims to reenact embryogenesis, maturation and aging of spinal
motor neurons (spMNs) in vitro. As the maturity of spMNs grown in vitro compared
to spMNs in vivo remains largely unaddressed, it is unclear to what extent this
in vitro system captures critical aspects of spMN development and molecular
signatures associated with ALS. Here, we compared transcriptomes among
iPSC-derived spMNs, fetal spinal tissues and adult spinal tissues. This approach
produced a maturation scale revealing that iPSC-derived spMNs were more similar
to fetal spinal tissue than to adult spMNs. Additionally, we resolved gene
networks and pathways associated with spMN maturation and aging. These networks
enriched for pathogenic familial ALS genetic variants and were disrupted in
sporadic ALS spMNs. Altogether, our findings suggest that developing strategies
to further mature and age iPSC-derived spMNs will provide more effective iPSC
models of ALS pathology. Amyotrophic lateral sclerosis (ALS) is an adult onset disease but with an
increasingly recognized preclinical prodrome. A wide spectrum of investigative
approaches has identified loss of inhibitory function at the heart of ALS. In
developing an explanation for the onset of ALS, it remains a consideration that
ALS has its origins in neonatal derangement of the γ-aminobutyric acid
(GABA)-ergic system, with delayed conversion from excitatory to mature
inhibitory GABA and impaired excitation/inhibition balance. If this is so, the
resulting chronic excitotoxicity could marginalize cortical network functioning
very early in life, laying the path for neurodegeneration. The possibility that
adult-onset neurodegenerative conditions might have their roots in early
developmental derangements is worthy of consideration, particularly in relation
to current models of disease pathogenesis. Unraveling the very early molecular
events will be crucial in developing a better understanding of ALS and other
adult neurodegenerative disorders. Muscle Nerve, 2019. Plasticity of the cerebral cortex following a modification of the sensorimotor
experience takes place in several steps that can last from few hours to several
months. Among the mechanisms involved in the dynamic modulation of the cerebral
cortex in adults, it is commonly proposed that short-term plasticity reflects
changes in synaptic connections. Here, we were interested in the time-course of
synaptic plasticity taking place in the somatosensory primary cortex all along a
14-day period of sensorimotor perturbation (SMP), as well as during a recovery
phase up to 24 h. Activation and expression level of pre- (synapsin 1,
synaptophysin, synaptotagmin 1) and postsynaptic (AMPA and NMDA receptors)
proteins, postsynaptic density scaffold proteins (PSD-95 and Shank2), and
cytoskeletal proteins (neurofilaments-L and M, β3-tubulin, synaptopodin,
N-cadherin) were determined in cortical tissue enriched in synaptic proteins.
During the SMP period, most changes were observed as soon as D7 in the
presynaptic compartment and were followed, at D14, by changes in the
postsynaptic compartment. These changes persisted at least until 24 h of
recovery. Proteins involved in synapse structure (scaffolding, adhesion,
cytoskeletal) were mildly affected and almost exclusively at D14. We concluded
that experience-dependent reorganization of somatotopic cortical maps is
accompanied by changes in synaptic transmission with a very close time-course. |
Is thalidomide used as an immunomodulatory drug nowadays? | Yes. | The sedative thalidomide was withdrawn from the market 30 years ago because of
its teratogenic and neurotoxic adverse effects. The compound was later
discovered to be extremely effective in the treatment of erythema nodosum
leprosum, a complication of lepromatous leprosy. This effect is probably due to
a direct influence on the immune system, because thalidomide possesses no
antibacterial activity. The compound is presently used as an experimental drug
in the treatment of a variety of diseases with an autoimmune character,
including recurrent aphthosis of nonviral and nonfungal origin in human
immunodeficiency virus (HIV) patients. This article reviews the most important
chemical and pharmacokinetic properties of thalidomide. The possible mechanisms
of the nonsedative effects of thalidomide with respect to the safety of its use
in HIV patients are discussed. Because the mechanism of the immunomodulatory
effect of thalidomide is unknown, the possibility that the administration of
this compound will accelerate the deterioration of the immunological status of
HIV patients cannot be excluded. Clinical evidence suggests that thalidomide may
aggravate the condition of patients with preexisting peripheral neuropathy.
Hypersensitivity reactions to thalidomide may occur more frequently in HIV
patients than in other patient groups. Because of the teratogenic activity of
thalidomide, reliable contraception must be provided to female patients of
childbearing age. Before the introduction of thalidomide therapy to an HIV
patient presenting with oral ulcers, a fungal or viral origin of the lesions
should be excluded. Thalidomide should not be used in patients with preexisting
HIV-related peripheral polyneuropathy, polyradiculopathy or encephalopathy. In
patients experiencing a complete remission, the discontinuation of thalidomide
treatment and its reintroduction in the case of a relapse are preferable to
maintece therapy. It has been more than three decades since the withdrawal of thalidomide from the
marketplace. Thalidomide is attracting growing interest because of its reported
immunomodulatory and anti-inflammatory properties. Current evidence indicates
that thalidomide reduces the activity of the inflammatory cytokine tumor
necrosis factor-alpha by accelerating the degradation of its messenger RNA.
Thalidomide inhibits angiogenesis. Recently, thalidomide was approved for sale
in the United States for the treatment of erythema nodosum leprosum, an
inflammatory complication of Hansen's disease. Thalidomide has been used
successfully in several other dermatologic disorders, including aphthous
stomatitis, Behcet's syndrome, chronic cutaneous systemic lupus erythematosus,
and graft-versus-host disease, the apparent shared characteristic of which is
immune dysregulation. Many recent studies have evaluated thalidomide in patients
with HIV infection, in which this drug is an efficacious agent against oral
aphthous ulcers, HIV-associated wasting syndrome, HIV-related diarrhea, and
Kaposi's sarcoma. Only in the last several years has thalidomide been
aggressively investigated for its antiangiogenic potential and immunomodulatory
properties in various tumor types. Current research on thalidomide in oncology
covers investigation in a wide range of both solid tumors and hematologic
maligcies. Thalidomide was withdrawn from the market in the early sixties because of its
teratogenic effects. Despite forty years of research, the mechanism of
thalidomide embryopathy has remained unsolved. Thalidomide has various
immunomodulatory effects. Thalidomide inhibits TNF alpha production, has T-cell
costimulatory properties and modulates the expression of cell surface molecules
on leukocytes in vivo. Thalidomide also has anti-angiogenic activity in vivo.
Angiogenesis plays an important role in the pathogenesis of both solid tumours
and hematologic maligcies such as multiple myeloma and lymphoma. In clinical
studies, thalidomide has been used as an inhibitor of angiogenesis. Erythema
nodosum leprosum is the only registered indication for the use of thalidomide in
the United States of America. Thalidomide is also effective in the treatment of
chronic graft-versus-host disease, mucocutaneous lesions in Behçet's syndrome
and HIV infections, and multiple myeloma. Thalidomide is an immunomodulatory agent; although its mechanisms of action are
not fully understood, many authors have described its anti-inflammatory and
immunosuppressive properties. More interestingly, thalidomide has shown the
ability to suppress tumor necrosis factor alpha (TNF alpha) production and to
modify the expression of TNF alpha induced adhesion molecules on endothelial
cells and on human leukocytes. Thalidomide has been used in several diseases
(i.e. dermatological, autoimmune, gastrointestinal). In this review we focus
specifically on the use of this drug in disorders with rheumatological features
such as lupus erythematosus, rheumatoid arthritis and Still's disease,
ankylosing spondylitis, and Behçet's disease. Despite its well known side
effects, first of all peripheral nerve involvement and teratogenesis, which can
be avoided by following strict guidelines, thalidomide could represent an
alternative drug in some rheumatological conditions, particularly in patients
who show resistance, contraindication or toxicity with other conventional
treatments. Thalidomide was introduced as a sedative and antiemetic agent to the European
market in the late 1950s. However, it soon became clear that a hitherto
unheard-of incidence of severe birth defects was due to the maternal use of
thalidomide and the drug was withdrawn from the market. Despite its
teratogenesis, thalidomide is currently being rediscovered because of its known
spectrum of anticachectic, antiemetic, mildly hypnotic, anxiolytic,
anti-inflammatory, antiangiogenic, and analgesic properties. The mechanism of
action of thalidomide is probably based on its immunomodulatory effect, namely
the suppression of production of tumor necrosis factor alpha and the modulation
of interleukins. A striking but not well-known finding is the effectiveness of
thalidomide as an analgesic or analgesic adjuvant. During the early era of
thalidomide use, the drug was shown to enhance the analgesic efficacy of a
combined treatment with acetylsalicylic acid, phenacetin, and caffeine (APC) by
testing "normal volunteers, using electrical stimulation of teeth." The
combination of thalidomide and APC was superior to other combinations (APC
alone, APC and codeine) with respect to both the total analgesic effect and the
duration of this analgesic effect. In 1965 thalidomide was found to be effective
in treating the painful subcutaneous manifestations of the leprosy-associated
erythema nodosum leprosum, a condition for which it eventually was approved by
the United States Food and Drug Administration in 1998. In an animal model of
neuropathic pain (chronic constriction injury), thalidomide was shown to reduce
both mechanical allodynia and thermal hyperalgesia. Recent studies documented
the analgesic efficacy of thalidomide in treating painful mucocutaneous aphthous
ulcers associated with HIV syndrome and Behcet's disease.However, to date there
are no recent clinical trials that are specifically designed to explore the
analgesic potential of thalidomide. In view of the current basic research and
clinical findings,we suggest to investigate the potential benefits of
thalidomide in severe pain conditions that respond poorly to common pain
management approaches such as neuropathic pain, postherpetic neuralgia, or
central pain phenomena. Because its mechanism of action is distinct from that of
other drugs such as steroids, thalidomide offers the possibility of a combined
treatment with other agents with nonoverlapping toxicities. We conclude that
thalidomide, when used properly,may enrich the therapeutic regimen in the
management of some pain-related conditions. Thalidomide has recently shown considerable promise in the treatment of a number
of conditions, such as leprosy and cancer. Its effectiveness in the clinic has
been ascribed to wide-ranging properties, including anti-TNF-alpha, T-cell
costimulatory and antiangiogenic activity. Novel compounds with improved
immunomodulatory activity and side effect profiles are also being evaluated.
These include selective cytokine inhibitory drugs (SelCIDs), with greatly
improved TNF-alpha inhibitory activity, and immunomodulatory drugs (IMiDs) that
are structural analogs of thalidomide, with improved properties. A third group
recently identified within the SelCID group, with phosphodiesterase type
4-independent activity, is in the process of being characterized in laboratory
studies. This review describes the emerging immunological properties of
thalidomide, from a historical context to present-day clinical applications,
most notably in multiple myeloma but also in other cancers, inflammatory
disease, and HIV. We also describe the laboratory studies that have led to the
characterization and development of SelCIDs and IMiDs into potentially
clinically relevant drugs. Early trial data suggest that these novel
immunomodulatory compounds may supercede thalidomide to become established
therapies, particularly in certain cancers. Further evidence is required,
however, to correlate the clinical efficacy of these compounds with their known
immunomodulatory, antiangiogenic, and antitumor properties. After nearly decades of extinction as a sedative and antiemetic, thalidomide
reemerged as the parent compound of a novel and promising class of therapeutics
termed the immunomodulatory drugs (IMiDs). The analogues of thalidomide, CC-5013
(lenalidomide, Revlimid) and CC-4047 (Actimid) are more potent regulators of
cellular immune and cytokine response while lacking some of the dose limiting
side effects of the parent compound, such as neurologic toxicity. Preclinical
data will be reviewed that outlines these drugs' effects on tumor necrosis
alpha, interleukin 12, angiogenesis, and T-cell function. The evolution of the
use of thalidomide as a therapeutic for diseases such as multiple myeloma and
myelodysplastic syndrome and the promising initial results of the new IMiDs will
be reviewed. Over the past 50 years, thalidomide has been a target of active investigation in
both maligt and inflammatory conditions. Although initially developed for its
sedative properties, decades of investigation have identified a multitude of
biological effects that led to its classification as an immunomodulatory drug
(IMiD). In addition to suppression of tumor necrosis factor-alpha (TNF-alpha),
thalidomide effects the generation and elaboration of a cascade of
pro-inflammatory cytokines that activate cytotoxic T-cells even in the absence
of co-stimulatory signals. Furthermore, vascular endothelial growth factor
(VEGF) and beta fibroblast growth factor (bFGF) secretion and cellular response
are suppressed by thalidomide, thus antagonizing neoangiogenesis and altering
the bone marrow stromal microenvironment in hematologic maligcies. The
thalidomide analogs, lenalidomide (CC-5013; Revlimid) and CC-4047 (Actimid),
have enhanced potency as inhibitors of TNF-alpha and other inflammatory
cytokines, as well as greater capacity to promote T-cell activation and suppress
angiogenesis. Both thalidomide and lenalidomide are effective in the treatment
of multiple myeloma and myelodysplastic syndromes for which the Food and Drug
Administration granted recent approval. Nonetheless, each of these IMiDs remains
the subject of active investigation in solid tumors, hematologic maligcies,
and other inflammatory conditions. This review will explore the pharmacokinetic
and biologic effects of thalidomide and its progeny compounds. It is now recognized that all cases of multiple myeloma (MM) are preceded by the
premaligt condition of monoclonal gammopathy of undetermined significance
(MGUS). Although patients with MGUS are generally asymptomatic and currently
managed by "watch and wait," the identification of high-risk patients whose
disease will progress more rapidly to smoldering MM (SMM) and MM aids in timely
intervention. The immunomodulatory agents thalidomide and lenalidomide and the
proteasome inhibitor bortezomib are now routine components of MM therapy in both
first-line and relapsed/ refractory settings. These targeted agents are used in
various combinations with chemotherapy for the treatment of both
transplantation-ineligible and transplantation-eligible patients. More recently,
a trend toward evaluation of 3- and 4-drug multiagent combinations before
transplantation and prolongation of primary therapy has generated new treatment
paradigms. Ultimately, the physician's choice of therapy and treatment strategy
requires consideration of regimen-associated toxicities and integration of the
patient's risk, comorbid status, and response and tolerability of previous
treatment regimens. Particular attention needs to be paid to baseline and/or
treatment-emergent peripheral neuropathy, thrombotic risk, changes in renal
function, and bone health. Despite recent advances, all patients with MM
eventually relapse, and efforts to identify novel synergistic combinations and
new agents are ongoing. This review highlights challenges in the clinic and
newer approaches under evaluation for the treatment and/or management of
patients with MGUS, SMM, and MM. Thalidomide is a drug with bad reputation from the 1960's as it appeared to be
teratogenic by causing foetal anomalies. However, in the beginning of 1990s it
was shown very antiangiogenic. Its immunological effects were known already from
earlier studies. Nowadays its use is accepted in myeloma therapy. It is also
used in many study protocols, e.g. in pediatric patients with brainstem tumors.
Thalidomide should be used very cautiously for fertile patients because of its
teratogenity. Other adverse effects are tiredness, obstipation, thrombosis, and
polyneuropathy. Thalidomide was developed in the 1950s as a sedative drug and withdrawn in 1961
because of its teratogenic effects, but has been rediscovered as an
immuno-modulatory drug. It has been administered successfully for the treatment
of erythema nodosum leprosum, aphthous ulceration and cachexia in HIV disease,
inflammatory bowel diseases, and several maligt diseases. The suppressive
effect of thalidomide on the activation of the nuclear transcription factor
NF-κB may explain these effects of thalidomide. NF-κB is retained in the
cytoplasm with IκBα, and is activated by a wide variety of inflammatory stimuli
including TNF, IL-1 and endotoxin followed by its translocation to the nucleus.
Angiogenesis and organogenesis also require gene transcription and signal
translocation. The findings shed new light on the anti-inflammatory properties
of thalidomide and suggest pharmaceutical actions of thalidomide via
interference of transcription mechanism. I reviewed the effects of thalidomide
on auto-inflammatory diseases of childhood. Thalidomide is a drug that, since its development, has made history in the world
of medicine--having been withdrawn and now has returned with a boom as an
anticancer and immunomodulatory drug. However, its mode of action in various
diseases (i.e. different types of hematologic maligcies, solid tumors) as
well as in various infections (i.e. pneumonia, tuberculosis, HIV infection etc.)
and related inflammatory conditions is not well understood. As the immune system
plays an important role in the pathogenesis of both infection-related as well as
noninfectious (i.e. cancer) inflammatory diseases, much research has been done
in the past few years to discover and design better immunomodulatory agents.
Such immunomodulatory agents should be able to target the immune system in such
a way that host suffers minimum damage and normal function of the immune system
remains intact. In the present review an attempt is made to highlight the
immunomodulatory action of thalidomide in various pathologic conditions. The US Food and Drug Administration approved thalidomide and its analogues for
the treatment of erythema nodosum leprosum, in spite of the notoriety of reports
of severe birth defects in the middle of the last century. As immunomodulatory
drugs, thalidomide and its analogues have been used to effectively treat various
diseases. In the present review, preclinical data about the effects of
thalidomide and its analogues on the immune system are integrated, including the
effects of cytokines on transdifferentiation, the anti-inflammatory effect,
immune cell function regulation and angiogenesis. The present review also
investigates the latest developments of thalidomide as a therapeutic option for
the treatment of idiopathic pulmonary fibrosis, skin fibrosis, and
ophthalmopathies. Multiple myeloma (MM) is a disease of unknown, complex etiology that affects
primarily older adults. The course of the disease and the patients' survival
time are very heterogeneous, but over the last decade, clear progress in the
treatment of this incurable disease has been observed. Therapeutics that have
proven to be highly effective include the immunomodulatory drug thalidomide and
its newer analogs, lenalidomide and pomalidomide, as well as the proteasome
inhibitors bortezomib and carfilzomib. However, the administration of some of
the treatments, e.g., thalidomide or bortezomib, has also been associated with
the occurrence of a serious and common adverse effect, drug-induced peripheral
neuropathy. The mechanism of the development of the peripheral neuropathy is
poorly understood. Nevertheless, one of its potential causes could be inadequate
concentrations of crucial trophic factors, including neurotrophic and/or
angiogenic factors, which are responsible for the proliferation,
differentiation, survival and death of neuronal and nonneuronal cells. |
Does p85α homodimerize? | p110α-free p85α homodimerizes | The canonical action of the p85α regulatory subunit of phosphatidylinositol
3-kinase (PI3K) is to associate with the p110α catalytic subunit to allow
stimuli-dependent activation of the PI3K pathway. We elucidate a
p110α-independent role of homodimerized p85α in the positive regulation of PTEN
stability and activity. p110α-free p85α homodimerizes via two intermolecular
interactions (SH3:proline-rich region and BH:BH) to selectively bind
unphosphorylated activated PTEN. As a consequence, homodimeric but not monomeric
p85α suppresses the PI3K pathway by protecting PTEN from E3 ligase WWP2-mediated
proteasomal degradation. Further, the p85α homodimer enhances the lipid
phosphatase activity and membrane association of PTEN. Strikingly, we identified
cancer patient-derived oncogenic p85α mutations that target the homodimerization
or PTEN interaction surface. Collectively, our data suggest the equilibrium of
p85α monomer-dimers regulates the PI3K pathway and disrupting this equilibrium
could lead to disease development. |
Which are the components that evaluate druglikeness? | Lipinski's rule states that, in general, an orally active drug has no more than one violation of the following criteria:
No more than 5 hydrogen bond donors (the total number of nitrogen–hydrogen and oxygen–hydrogen bonds)
No more than 10 hydrogen bond acceptors (all nitrogen or oxygen atoms)
A molecular mass less than 500 daltons
An octanol-water partition coefficient (log P) that does not exceed 5 | Combinatorial chemistry needs focused molecular diversity applied to the
druglike chemical space (drugspace). A drugspace map can be obtained by
systematically applying the same conventions when examining the chemical space,
in a manner similar to the Mercator convention in geography: Rules are
equivalent to dimensions (e.g., longitude and latitude), while structures are
equivalent to objects (e.g., cities and countries). Selected rules include size,
lipophilicity, polarizability, charge, flexibility, rigidity, and hydrogen bond
capacity. For these, extreme values were set, e.g., maximum molecular weight
1500, calculated negative logarithm of the octanol/water partition between -10
and 20, and up to 30 nonterminal rotatable bonds. Only S, N, O, P, and halogens
were considered as elements besides C and H. Selected objects include a set of
"satellite" structures and a set of representative drugs ("core" structures).
Satellites, intentionally placed outside drugspace, have extreme values in one
or several of the desired properties, while containing druglike chemical
fragments. ChemGPS (chemical global positioning system) is a tool that combines
these predefined rules and objects to provide a global drugspace map. The
ChemGPS drugspace map coordinates are t-scores extracted via principal component
analysis (PCA) from 72 descriptors that evaluate the above-mentioned rules on a
total set of 423 satellite and core structures. Global ChemGPS scores describe
well the latent structures extracted with PCA for a set of 8599
monocarboxylates, a set of 45 heteroaromatic compounds, and for 87 alpha-amino
acids. ChemGPS positions novel structures in drugspace via PCA-score prediction,
providing a unique mapping device for the druglike chemical space. ChemGPS
scores are comparable across a large number of chemicals and do not change as
new structures are predicted, making this tool a well-suited reference system
for comparing multiple libraries and for keeping track of previously explored
regions of the chemical space. Adequate bioavailability is one of the essential properties for an orally
administered drug. Lipinski and others have formulated simplified rules in which
compounds that satisfy selected physiochemical properties, for example,
molecular weight (MW) ≤ 500 or the logarithm of the octanol-water partition
coefficient, log P(o/w) < 5, are anticipated to likely have pharmacokinetic
properties appropriate for oral administration. However, these schemes do not
simultaneously consider the combination of the physiochemical properties,
complicating their application in a more automated fashion. To overcome this, we
present a novel method to select compounds with a combination of physicochemical
properties that maximize bioavailability and druglikeness based on compounds in
the World Drug Index database. In the study four properties, MW, log P(o/w),
number of hydrogen bond donors, and number of hydrogen acceptors, were combined
into a 4-dimensional (4D) histogram, from which a scoring function was defined
on the basis of a 4D dependent multivariate Gaussian model. The resulting
equation allows for assigning compounds a bioavailability score, termed 4D-BA,
such that chemicals with higher 4D-BA scores are more likely to have oral
druglike characteristics. The descriptor is validated by applying the function
to drugs previously categorized in the Biopharmaceutics Classification System,
and examples of application of the descriptor are given in the context of
previously published studies targeting heme oxygenase and SHP2 phosphatase. The
approach is anticipated to be useful in early lead identification studies in
combination with clustering methods to maximize chemical and structural
diversity when selecting compounds for biological assays from large database
screens. It may also be applied to prioritize synthetically feasible chemical
modifications during lead compound optimization. The chemical structure of a drug determines its physicochemical properties,
further determines its ADME/Tox properties, and ultimately affects its
pharmacological activity. Medicinal chemists can regulate the pharmacological
activity of drug molecules by modifying their structure. Ring systems and
functional groups are important components of a drug. The proportion of
non-hydrocarbon atoms among non-hydrogen atoms reflects the heavy atoms
proportion of a drug. The three factors have considerable potential for the
assessment of the drug-like properties of organic molecules. However, to the
best of our knowledge, there have been no studies to systematically analyze the
simultaneous effects of the number of aromatic and non-aromatic rings, the
number of some special functional groups and the proportion of heavy atoms on
the drug-like properties of an organic molecule. To this end, the numbers of
aromatic and non-aromatic rings, the numbers of some special functional groups
and the heavy atoms proportion of 6891 global approved small drugs have been
comprehensively analyzed. We first uncovered three important structure-related
criteria closely related to drug-likeness, namely: (1) the best numbers of
aromatic and non-aromatic rings are 2 and 1, respectively; (2) the best
functional groups of candidate drugs are usually -OH, -COOR and -COOH in turn,
but not -CONHOH, -SH, -CHO and -SO3H. In addition, the -F functional group is
beneficial to CNS drugs, and -NH2 functional group is beneficial to
anti-infective drugs and anti-cancer drugs; (3) the best R value intervals of
candidate drugs are in the range of 0.05-0.50 (preferably 0.10-0.35), and R
value of the candidate CNS drugs should be as small as possible in this
interval. We envision that the three chemical structure-related criteria may be
applicable in a prospective manner for the identification of novel candidate
drugs and will provide a theoretical foundation for designing new chemical
entities with good drug-like properties. In the present work, the anti-inflammatory and antiasthmatic potential of
biseugenol, isolated as the main component from n-hexane extract from leaves of
Nectandra leucantha and chemically prepared using oxidative coupling from
eugenol, was evaluated in an experimental model of mixed-granulocytic asthma.
Initially, in silico studies of biseugenol showed good predictions for
drug-likeness, with adherence to Lipinski's rules of five (RO5), good
Absorption, Distribution, Metabolism and Excretion (ADME) properties and no
alerts for Pan-Assay Interference Compounds (PAINS), indicating adequate
adherence to perform in vivo assays. Biseugenol (20 mg·kg-1) was thus
administered intraperitoneally (four days of treatment) and resulted in a
significant reduction in both eosinophils and neutrophils of bronchoalveolar
lavage fluid in ovalbumin-sensitized mice with no statistical difference from
dexamethasone (5 mg·kg-1). As for lung function parameters, biseugenol (20
mg·kg-1) significantly reduced airway and tissue damping in comparison to
ovalbumin group, with similar efficacy to positive control dexamethasone. Airway
hyperresponsiveness to intravenous methacholine was reduced with biseugenol but
was inferior to dexamethasone in higher doses. In conclusion, biseugenol
displayed antiasthmatic effects, as observed through the reduction of
inflammation and airway hyperresponsiveness, with similar effects to
dexamethasone, on mixed-granulocytic ovalbumin-sensitized mice. |
Do angiotensin-converting-enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) increase the likelihood of severe COVID-19? | No. Patients receiving angiotensin-converting-enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) should continue treatment with these agents if there is no other reason for discontinuation. Despite speculation that patients with COVID-19 who are receiving these agents may be at increased risk for adverse outcomes, accumulating evidence does not support an association of ACE inhibitors and ARBs with more severe disease. In addition, stopping these agents in some patients can exacerbate comorbid cardiovascular or kidney disease and increase mortality. | Concerns have been raised regarding the safety of angiotensin converting enzyme
inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in patients with
coronavirus disease of 2019 (COVID-19), based on the hypothesis that such
medications may raise expression of ACE2, the receptor for severe acute
respiratory syndrome-coronavirus 2 (SARS-CoV-2). We conducted a literature
review of studies (n = 12) in experimental animals and human subjects (n = 12)
and evaluated the evidence regarding the impact of administration of ACEIs and
ARBs on ACE2 expression. We prioritized studies that assessed ACE2 protein
expression data, measured directly or inferred from ACE2 activity assays. The
findings in animals are inconsistent with respect to an increase in ACE2
expression in response to treatment with ACEIs or ARBs. Control/sham animals
show little to no effect in the plurality of studies. Those studies that report
increases in ACE2 expression tend to involve acute injury models and/or higher
doses of ACEIs or ARBs than are typically administered to patients. Data from
human studies overwhelmingly imply that administration of ACEIs/ARBs does not
increase ACE2 expression. Available evidence, in particular, data from human
studies, does not support the hypothesis that ACEI/ARB use increases ACE2
expression and the risk of complications from COVID-19. We conclude that
patients being treated with ACEIs and ARBs should continue their use for
approved indications. BACKGROUND: The role of angiotensin-converting enzyme inhibitors (ACEIs) and
angiotensin-receptor blockers (ARBs) in coronavirus disease 2019 (COVID-19)
susceptibility, severity, and treatment is unclear.
PURPOSE: To evaluate, on an ongoing basis, whether use of ACEIs or ARBs either
increases risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
infection or is associated with worse COVID-19 disease outcomes, and to assess
the efficacy of these medications for COVID-19 treatment.
DATA SOURCES: MEDLINE (Ovid) and Cochrane Database of Systematic Reviews from
2003 to 4 May 2020, with planned ongoing surveillance for 1 year; the World
Health Organization database of COVID-19 publications and medRxiv.org through 17
April 2020; and ClinicalTrials.gov to 24 April 2020, with planned ongoing
surveillance.
STUDY SELECTION: Observational studies and trials in adults that examined
associations and effects of ACEIs or ARBs on risk for SARS-CoV-2 infection and
COVID-19 disease severity and mortality.
DATA EXTRACTION: Single-reviewer abstraction confirmed by another reviewer,
independent evaluation by 2 reviewers of study quality, and collective
assessment of certainty of evidence.
DATA SYNTHESIS: Two retrospective cohort studies found that ACEI and ARB use was
not associated with a higher likelihood of receiving a positive SARS-CoV-2 test
result, and 1 case-control study found no association with COVID-19 illness in a
large community (moderate-certainty evidence). Fourteen observational studies,
involving a total of 23 565 adults with COVID-19, showed consistent evidence
that neither medication was associated with more severe COVID-19 illness
(high-certainty evidence). Four registered randomized trials plan to evaluate
ACEIs and ARBs for treatment of COVID-19.
LIMITATION: Half the studies were small and did not adjust for important
confounding variables.
CONCLUSION: High-certainty evidence suggests that ACEI or ARB use is not
associated with more severe COVID-19 disease, and moderate-certainty evidence
suggests no association between use of these medications and positive SARS-CoV-2
test results among symptomatic patients. Whether these medications increase the
risk for mild or asymptomatic disease or are beneficial in COVID-19 treatment
remains uncertain.
PRIMARY FUNDING SOURCE: None. (PROSPERO: registration number pending). Angiotensin-converting enzyme (ACE) inhibitors (ACEIs) and angiotensin II type‑1
receptor blockers (ARBs) are among the most widely prescribed drugs for the
treatment of arterial hypertension, heart failure and chronic kidney disease.
A number of studies, mainly in animals and not involving the lungs, have
indicated that these drugs can increase expression of angiotensin-converting
enzyme 2 (ACE2). ACE2 is the cell entry receptor of severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease
2019 (COVID-19) that is currently battering the globe. This has led to the
hypothesis that use of ACEIs and ARBs may increase the risk of developing severe
COVID-19. In this point of view paper, possible scenarios regarding the impact
of ACEI/ARB pharmacotherapy on COVID-19 are discussed in relation to the
currently available evidence. Although further research on the influence of
blood-pressure-lowering drugs, including those not targeting the
renin-angiotensin system, is warranted, there are presently no compelling
clinical data showing that ACEIs and ARBs increase the likelihood of contracting
COVID-19 or worsen the outcome of SARS-CoV‑2 infections. Thus, unless
contraindicated, use of ACEIs/ARBs in COVID-19 patients should be continued in
line with the recent recommendations of medical societies. IMPORTANCE: It has been hypothesized that angiotensin-converting enzyme
inhibitors (ACEIs)/angiotensin receptor blockers (ARBs) may make patients more
susceptible to coronavirus disease 2019 (COVID-19) and to worse outcomes through
upregulation of the functional receptor of the virus, angiotensin-converting
enzyme 2.
OBJECTIVE: To examine whether use of ACEI/ARBs was associated with COVID-19
diagnosis and worse outcomes in patients with COVID-19.
DESIGN, SETTING, AND PARTICIPANTS: To examine outcomes among patients with
COVID-19, a retrospective cohort study using data from Danish national
administrative registries was conducted. Patients with COVID-19 from February 22
to May 4, 2020, were identified using ICD-10 codes and followed up from day of
diagnosis to outcome or end of study period (May 4, 2020). To examine
susceptibility to COVID-19, a Cox regression model with a nested case-control
framework was used to examine the association between use of ACEI/ARBs vs other
antihypertensive drugs and the incidence rate of a COVID-19 diagnosis in a
cohort of patients with hypertension from February 1 to May 4, 2020.
EXPOSURES: ACEI/ARB use was defined as prescription fillings 6 months prior to
the index date.
MAIN OUTCOMES AND MEASURES: In the retrospective cohort study, the primary
outcome was death, and a secondary outcome was a composite outcome of death or
severe COVID-19. In the nested case-control susceptibility analysis, the outcome
was COVID-19 diagnosis.
RESULTS: In the retrospective cohort study, 4480 patients with COVID-19 were
included (median age, 54.7 years [interquartile range, 40.9-72.0]; 47.9% men).
There were 895 users (20.0%) of ACEI/ARBs and 3585 nonusers (80.0%). In the
ACEI/ARB group, 18.1% died within 30 days vs 7.3% in the nonuser group, but this
association was not significant after adjustment for age, sex, and medical
history (adjusted hazard ratio [HR], 0.83 [95% CI, 0.67-1.03]). Death or severe
COVID-19 occurred in 31.9% of ACEI/ARB users vs 14.2% of nonusers by 30 days
(adjusted HR, 1.04 [95% CI, 0.89-1.23]). In the nested case-control analysis of
COVID-19 susceptibility, 571 patients with COVID-19 and prior hypertension
(median age, 73.9 years; 54.3% men) were compared with 5710 age- and sex-matched
controls with prior hypertension but not COVID-19. Among those with COVID-19,
86.5% used ACEI/ARBs vs 85.4% of controls; ACEI/ARB use compared with other
antihypertensive drugs was not significantly associated with higher incidence of
COVID-19 (adjusted HR, 1.05 [95% CI, 0.80-1.36]).
CONCLUSIONS AND RELEVANCE: Prior use of ACEI/ARBs was not significantly
associated with COVID-19 diagnosis among patients with hypertension or with
mortality or severe disease among patients diagnosed as having COVID-19. These
findings do not support discontinuation of ACEI/ARB medications that are
clinically indicated in the context of the COVID-19 pandemic. AIMS: This retrospective case-control study was aimed at identifying potential
independent predictors of severe/lethal COVID-19, including the treatment with
Angiotensin-Converting Enzyme inhibitors (ACEi) and/or Angiotensin II Receptor
Blockers (ARBs).
METHODS AND RESULTS: All adults with SARS-CoV-2 infection in two Italian
provinces were followed for a median of 24 days. ARBs and/or ACEi treatments,
and hypertension, diabetes, cancer, COPD, renal and major cardiovascular
diseases (CVD) were extracted from clinical charts and electronic health
records, up to two years before infection. The sample consisted of 1603 subjects
(mean age 58.0y; 47.3% males): 454 (28.3%) had severe symptoms, 192 (12.0%) very
severe or lethal disease (154 deaths; mean age 79.3 years; 70.8% hypertensive,
42.2% with CVD). The youngest deceased person aged 44 years. Among hypertensive
subjects (n = 543), the proportion of those treated with ARBs or ACEi were
88.4%, 78.7% and 80.6% among patients with mild, severe and very severe/lethal
disease, respectively. At multivariate analysis, no association was observed
between therapy and disease severity (Adjusted OR for very severe/lethal
COVID-19: 0.87; 95% CI: 0.50-1.49). Significant predictors of severe disease
were older age (with AORs largely increasing after 70 years of age), male gender
(AOR: 1.76; 1.40-2.23), diabetes (AOR: 1.52; 1.05-2.18), CVD (AOR: 1.88;
1.32-2.70) and COPD (AOR: 1.88; 1.11-3.20). Only gender, age and diabetes also
predicted very severe/lethal disease.
CONCLUSION: No association was found between COVID-19 severity and treatment
with ARBs and/or ACEi, supporting the recommendation to continue medication for
all patients unless otherwise advised by their physicians. Author information:
(1)Division of Population Health and Genomics, University of Dundee, UK.
(2)Observational Health Data Analytics, Janssen Research and Development,
Titusville, NJ, USA.
(3)Department of Biomedical Informatics, Ajou University School of Medicine,
Suwon, Korea.
(4)Quality Use of Medicines and Pharmacy Research Centre, Clinical and Health
Sciences, University of South Australia, Adelaide, Australia.
(5)Real World Solutions, IQVIA, Cambridge, MA, USA.
(6)Fundació Institut Universitari per a la recerca a l'Atenció Primària de Salut
Jordi Gol i Gurina (IDIAPJGol), Barcelona, Spain.
(7)Department of Veterans Affairs, Salt Lake City, UT, USA.
(8)University of Utah School of Medicine, Salt Lake City, UT, USA.
(9)Department of Biomedical Informatics, Columbia University, New York, USA.
(10)The Hyve, Utrecht, Netherlands.
(11)Translational Discovery, Bill & Melinda Gates Medical Research Institute,
Seattle, WA, USA.
(12)Geriatric Research Education, and Clinical Care Center, Tennessee Valley
Healthcare System VA, Nashville, TN.
(13)Department of Biomedical Informatics, Vanderbilt University Medical Center,
Nashville, TN, USA.
(14)Department of Internal Medicine, University of New Mexico Health Sciences
Center, Albuquerque, NM, USA.
(15)School of Public Health and Community Medicine, Institute of Medicine,
Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
(16)Medication Safety Research Chair, King Saud University, Riyadh, Saudi
Arabia.
(17)Tufts Medical Center, Tufts University, Boston, MA, USA.
(18)Department of Medical Informatics, Erasmus University Medical Center,
Rotterdam, Netherlands.
(19)Centre for Statistics in Medicine, Nuffield Department of Orthopaedics,
Rheumatology and Musculoskeletal Sciences, Oxford University, Oxford, UK.
(20)School of Public Health, Peking Union Medical College and Chinese Academy of
Medical Sciences, Beijing, China.
(21)Melbourne School of Public Health, The University of Melbourne, Victoria,
Australia.
(22)Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford,
UK.
(23)Section of Cardiovascular Medicine, Department of Medicine, Yale University,
New Haven, CT, USA.
(24)Department of Biostatistics, UCLA Fielding School of Public Health,
University of California, Los Angeles, Los Angeles, CA, USA.
(25)Department of Computational Medicine, David Geffen School of Medicine at
UCLA, University of California, Los Angeles, Los Angeles, CA, USA. INTRODUCCIÓN: Existe controversia respecto al uso de los inhibidores de la
enzima convertidora de angiotensina (IECA) o los bloqueadores de los receptores
tipo I de la angiotensina II (ARA-II) para el tratamiento de la hipertensión
arterial en COVID-19. Se ha sugerido que estos fármacos podrían tanto aumentar
como reducir el riesgo de COVID-19 grave.
PACIENTES Y MÉTODO: Estudio de cohortes retrospectivo de pacientes consecutivos
de un área sanitaria, con hipertensión e infección por SARS-CoV-2. Variable de
resultados: ingreso hospitalario por COVID-19 grave.
RESULTADOS: Fueron diagnosticados 539 sujetos por infección por SARS-CoV-2. De
estos, 157 (29,1%) eran hipertensos y se incluyeron en el estudio. Se ingresaron
69 (43,9%) pacientes por COVID-19 grave. En el análisis multivariante, la edad
más elevada, la diabetes y la miocardiopatía hipertensiva se relacionaron con el
riesgo de ingreso hospitalario. El tratamiento con ARA-II se asoció con un
riesgo significativamente más bajo de ingreso (HR: 0,29, IC 95%: 0,10-0,88). Una
tendencia similar, aunque no significativa, se encontró para los IECA.
CONCLUSIÓN: el tratamiento con ARA-II o IECA no se asoció con una peor evolución
clínica en pacientes hipertensos consecutivos infectados por SARS-CoV-2. There is current debate concerning the use of angiotensin-converting enzyme
(ACE) inhibitors or angiotensin II type 1 receptor blockers (ARBs), for
hypertension management, during COVID-19 infection. Specifically, the suggestion
has been made that ACE inhibitors or ARBs could theoretically contribute to
infection via increasing ACE2 receptor expression and hence increase viral load.
The ACE2 receptor is responsible for binding the SAR-CoV2 viral spike and
causing COVID-19 infection. What makes the argument somewhat obtuse for ACE
inhibitors or ARBs is that ACE2 receptor expression can be increased by
compounds that activate or increase the expression of SIRT1. Henceforth common
dietary interventions, vitamins and nutrients may directly or indirectly
influence the cellular expression of the ACE2 receptor. There are many common
compounds that can increase the expression of the ACE2 receptor including
Vitamin C, Metformin, Resveratrol, Vitamin B3 and Vitamin D. It is important to
acknowledge that down-regulation or blocking the cellular ACE2 receptor will
likely be pro-inflammatory and may contribute to end organ pathology and
mortality in COVID-19. In conclusion from the perspective of the ACE2 receptor,
COVID-19 prevention and treatment are distinctly different. This letter reflects
on this current debate and suggests angiotensin-converting enzyme inhibitors and
ARBs are likely beneficial during COVID-19 infection for hypertensive and
normotensive patients. INTRODUCTION: The use of renin-angiotensin system (RAS) inhibitors, including
angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor
blockers (ARBs), was alleged to cause a more severe course of novel coronavirus
disease 2019 (COVID-19).
METHODS: We systematically reviewed the published studies to assess the
association of RAS inhibitors with mortality as well as disease severity in
COVID-19 patients. A systematic literature search was performed to retrieve
relevant original studies investigating mortality and severity (severe/critical
disease) in COVID-19 patients with and without exposure to RAS inhibitors.
RESULTS: A total of 59 original studies were included for qualitative synthesis.
Twenty-four studies that reported adjusted effect sizes (24 studies reported
mortality outcomes and 16 studies reported disease severity outcomes), conducted
in RAS inhibitor-exposed and unexposed groups, were pooled in random-effects
models to estimate overall risk. Quality assessment of studies revealed that
most of the studies included were of fair quality. The use of an ACEI/ARB in
COVID-19 patients was significantly associated with lower odds (odds ratio
[OR] = 0.73, 95% confidence interval [CI] 0.56-0.95; n = 18,749) or hazard
(hazard ratio [HR] = 0.75, 95% CI 0.60-0.95; n = 26,598) of mortality compared
with non-use of ACEI/ARB. However, the use of an ACEI/ARB was non-significantly
associated with lower odds (OR = 0.91, 95% CI 0.75-1.10; n = 7446) or hazard
(HR = 0.73, 95% CI 0.33-1.66; n = 6325) of developing severe/critical disease
compared with non-use of an ACEI/ARB.
DISCUSSION: Since there was no increased risk of harm, the use of RAS inhibitors
for hypertension and other established clinical indications can be maintained in
COVID-19 patients. Considerable concern has emerged for the potential harm in the use of
angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor
inhibitors (ARBs) in COVID-19 patients, given that ACEIs and ARBs may increase
the expression of ACE2 receptors that represent the way for coronavirus 2 to
entry into the cell and cause severe acute respiratory syndrome. Assess the
effect of ACEI/ARBs on outcome in COVID-19 patients. Hospital-based prospective
study. A total of 431 patients consecutively presenting at the Emergency
Department and found to be affected by COVID-19 were assessed. Relevant clinical
and laboratory variables were recorded, focusing on the type of current anti
hypertensive treatment. Outcome variables were NO, MILD, SEVERE respiratory
distress (RD) operationally defined and DEATH. Hypertension was the single most
frequent comorbidity (221/431 = 51%). Distribution of antihypertensive treatment
was: ACEIs 77/221 (35%), ARBs 63/221 (28%), OTHER than ACEIs or ARBs 64/221
(29%). In 17/221 (8%) antihypertensive medication was unknown. The proportion of
patients taking ACEIs, ARBs or OTHERs who developed MILD or SEVERE RD was 43/77
(56%), 33/53 (52%), 39/64 (61%) and 19/77 (25%), 16/63 (25%) and 16/64 (25%),
respectively, with no statistical difference between groups. Despite producing a
RR for SEVERE RD of 2.59 (95% CI 1.93-3.49), hypertension was no longer
significant in a logistic regression analysis that identified age, CRP and
creatinine as the sole independent predictors of SEVERE RD and DEATH. ACEIs and
ARBs do not promote a more severe outcome of COVID-19. There is no reason why
they should be withheld in affected patients. Some have hypothesized that the use of angiotensin-converting enzyme inhibitors
(ACEI) and angiotensin-receptor blockers (ARB) may modify susceptibility to
coronavirus disease-2019 (COVID-19) in humans. Thus, we conducted two
meta-analyses to investigate the effect of ACEI and ARB on mortality and
susceptibility to COVID-19. Pubmed and EMBASE were searched through June 2020 to
identify clinical trials that investigated the testing positive and in-hospital
mortality rates for COVID-19 for those who were treated with ACEI and/or ARB and
for those who were not treated with ACEI or ARB. The first analysis investigated
the testing positive rate of COVID-19. The second analysis investigated the
in-hospital mortality rate for patients with COVID-19. Three eligible studies
for the first analysis and 14 eligible studies for the second analysis were
identified. The first analysis demonstrated that the use of ACEI or ARB did not
affect the testing positive rates (odds ratio [OR] [confidence interval
[CI]] = 0.96 [0.88-1.04]; p = .69, OR [CI] = 0.99 [0.91-1.08]; p = 0.35,
respectively). The second analysis showed that the use of ACEI and/or ARB did
not affect in-hospital mortality (risk ratio [RR] 95% [CI]] = 0.88 [0.64-1.20],
p = 0.42). The subgroup analysis by limiting studies of patients with
hypertension showed ACEI and/or ARB use was associated with a significant
reduction of in-hospital mortality compared with no ACEI or ARB use (RR
[CI] = 0.66 [0.49-0.89], p = 0.004). Our analysis demonstrated that ACEI and/or
ARB use was associated neither with testing positive rates of COVID-19 nor with
mortality of COVID-19 patients. Targeting the renin-angiotensin system is proposed to affect mortality due to
coronavirus disease 2019 (COVID-19). We aimed to compare the mortality rates in
COVID-19 patients who received angiotensin-converting enzyme inhibitors or
angiotensin receptor blockers (ACEIs/ARBs) and those who did not. In this
retrospective cohort study, mortality was considered as the main outcome
measure. All underlying diseases were assessed by the chronic use of medications
related to each condition. We defined two main groups based on the ACEIs/ARBs
administration. A logistic regression model was designed to define independent
predictors of mortality as well as a Cox regression analysis. In total, 2553
patients were included in this study. The mortality frequency was higher in
patients with a history of underlying diseases (22.4% vs 12.7%, P
value < 0.001). The mortality rate in patients who received ACEIs/ARBs were
higher than non-receivers (29.3% vs. 19.5%, P value = 0.013, OR = 1.3, 95% CI
1.1, 1.7) in the univariate analysis. However, the use of ACEIs/ARBs was a
protective factor against mortality in the model when adjusted for underlying
conditions, length of stay, age, gender, and ICU admission (P value < 0.001,
OR = 0.5, 95% CI 0.3, 0.7). The Kaplan-Meier curve showed an overall survival of
approximately 85.7% after a 120-day follow-up. ACEIs/ARBs are protective factors
against mortality in COVID-19 patients with HTN, and these agents can be
considered potential therapeutic options in this disease. The survival
probability is higher in ACEIs/ARBs receivers than non-receivers. Renin-angiotensin-aldosterone system (RAAS) inhibitors, including
angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor
blockers (ARBs) are one of the most prescribed antihypertensive medications.
Previous studies showed RAAS inhibitors increase the expression of ACE2, a
cellular receptor for severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2), which provokes a concern that the use of ACEI and ARB in
hypertensive individuals might lead to increased mortality and severity of
coronavirus disease 2019 (COVID-19). To further investigate the effects of
ACEI/ARB on COVID-19 patients, we systematically reviewed relevant studies that
met predetermined inclusion criteria in search of PubMed, Embase, Cochrane
Library databases, medRxiv, and bioRxiv. The search strategy included clinical
data published through October 12, 2020. Twenty-six studies involving 8104
hypertensive patients in ACEI/ARB-treated group and 8203 hypertensive patients
in non-ACEI/ARB-treated group were analyzed. Random-effects meta-analysis showed
ACEI/ARB treatment was significantly associated with a lower risk of mortality
in hypertensive COVID-19 patients (odds ratio [OR] = 0.624, 95% confidence
interval [CI] = 0.457-0.852, p = .003, I2 = 74.3%). Meta-regression analysis
showed that age, gender, study site, Newcastle-Ottawa Scale scores,
comorbidities of diabetes, coronary artery disease, chronic kidney disease, or
cancer has no significant modulating effect of ACEI/ARB treatment on the
mortality of hypertensive COVID-19 patients (all p > .1). In addition, the
ACEI/ARB treatment was associated with a lower risk of ventilatory support
(OR = 0.682, 95% CI = 0.475-1.978, p = .037, I2 = 0.0%). In conclusion, these
results suggest that ACEI/ARB medications should not be discontinued for
hypertensive patients in the context of COVID-19 pandemic. BACKGROUND: Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin
receptor blockers (ARBs) are known to increase the expression of angiotensin
converting enzyme 2 receptor, which has been shown to be the receptor for the
acute severe respiratory syndrome coronavirus 2 (SARS-CoV-2).
AREAS OF UNCERTAINTY: Based on these observations, speculations raised the
concerns that ACEIs/ARBs users would be more susceptible to SARS-CoV-2 infection
and would be at higher risk for severe COVID-19 disease and death. Therefore, we
systematically reviewed the literature and performed a meta-analysis of the
association between prior use of ACEIs and ARBs and mortality due to COVID-19
disease.
DATA SOURCES: A comprehensive search of several databases from November 2019 to
June 18, 2020 was conducted. The databases included Ovid MEDLINE(R) and Epub
Ahead of Print, In-Process and Other Non-Indexed Citations and Daily, Ovid
Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane
Database of Systematic Reviews, Web of Science, and Scopus. Medrxiv.org was also
searched for unpublished data.
THERAPEUTIC ADVANCES: Nine studies with a total of 18,833 patients infected with
SARS-CoV-2 met our eligibility criteria. Prior use of ACEIs and/or ARBs was
associated with reduced mortality among SARS-CoV-2-infected patients, with a
pooled adjusted relative risk (aRR) from 6 studies of 0.63, 95% confidence
interval (CI) (0.42-0.94) (I 2 = 65%). Three studies reported separately on
ACEIs or ARBs and their association with survival among SARS-CoV-2-infected
patients, with a pooled adjusted relative risk of 0.78, 95% CI (0.58-1.04) (I 2
= 0%) and 0.97, 95% CI (0.73-1.30) (I 2 = 0%) respectively. The results of
sensitivity analyses were consistent with the main analysis.
CONCLUSION: Our meta-analysis suggests that use of ACEIs/ARBs is associated with
a decreased risk of death among SARS-CoV-2-infected patients. This finding
provides a reassurance to the public not to stop prescribed ACEIs/ARBs because
of fear of severe COVID-19. BACKGROUND: COVID-19 is caused by the coronavirus SARS-CoV-2, which uses
angiotensin-converting enzyme 2 (ACE-2) as a receptor for cellular entry. It is
theorized that ACE inhibitors (ACE-Is) or angiotensin receptor blockers (ARBs)
may increase vulnerability to SARS-CoV-2 by upregulating ACE-2 expression, but
ACE-I/ARB discontinuation is associated with clinical deterioration.
OBJECTIVE: To determine whether ACE-I and ARB use is associated with acute
kidney injury (AKI), macrovascular thrombosis and in-hospital mortality.
METHODS: A retrospective, single-centre study of 558 hospital inpatients with
confirmed COVID-19 admitted from 1 March to 30 April 2020, followed up until 24
May 2020. AKI and macrovascular thrombosis were primary end-points, and
in-hospital mortality was a secondary end-point.
RESULTS: AKI occurred in 126 (23.1%) patients, 34 (6.1%) developed macrovascular
thrombi, and 200 (35.9%) died. Overlap propensity score-weighted analysis showed
no significant effect of ACE-I/ARB use on the risk of occurrence of the
specified end-points. On exploratory analysis, severe chronic kidney disease
(CKD) increases odds of macrovascular thrombi (OR: 8.237, 95% CI: 1.689-40.181,
P = 0.009). The risk of AKI increased with advancing age (OR: 1.028, 95% CI:
1.011-1.044, P = 0.001) and diabetes (OR: 1.675, 95% CI: 1.065-2.633,
P = 0.025). Immunosuppression was associated with lower risk of AKI (OR: 0.160,
95% CI: 0.029-0.886, P = 0.036). Advancing age, dependence on care, male gender
and eGFR < 60 mL min-1 /1.73 m2 increased odds of in-hospital mortality.
CONCLUSION: We did not identify an association between ACE-I/ARB use and AKI,
macrovascular thrombi or mortality. This supports the recommendations of the
European and American Societies of Cardiology that ACE-Is and ARBs should not be
discontinued during the COVID-19 pandemic. Association of renin-angiotensin system inhibitors with risk of death in
patients with hypertension (HTN) and coronavirus disease 2019 (COVID-19) is not
well characterized. The aim of this study was to evaluate the outcomes of
patients with HTN and COVID-19 with respect to different chronic
antihypertensive drug intake. We performed a retrospective, observational study
from a large cohort of patients with HTN and with a laboratory-confirmed severe
acute respiratory syndrome coronavirus 2 infection admitted to the Emergency
Rooms (ER) of the Piacenza Hospital network from February 21, 2020 to March 20,
2020. There were 1050 patients admitted to the ERs of the Piacenza Hospital
network with COVID-19. HTN was present in 590 patients [median age, 76.2 years
(IQR 68.2-82.6)]; 399 (66.1%) patients were male. Of them, 248 patients were
chronically treated with ACEi, 181 with ARBs, and 161 with other drugs (O-drugs)
including beta blockers, diuretics and calcium-channel inhibitors. With respect
to the antihypertensive use, there was no difference between comorbid
conditions. During a follow-up of 38 days (IQR 7.0-46.0), 256 patients (43.4%)
died, without any difference stratifying for antihypertensive drugs. Of them,
107 (43.1%) were in ACEi group vs 67 (37%) in ARBs group vs 82 (50.7%) in
O-drugs group, (log-rank test: p = 0.066). In patients with HTN and COVID-19,
neither ACEi nor ARBs were independently associated with mortality. After
adjusting for potential confounders in risk prediction, the rate of death was
similar. Our data confirm Specialty Societal recommendations, suggesting that
treatment with ACEIs or ARBs should not be discontinued because of COVID-19. BACKGROUND: Speculations whether treatment with angiotensin-converting enzyme
inhibitors (ACE-I) or angiotensin II receptor blockers (ARB) predisposes to
severe coronavirus disease 2019 (COVID-19) or worsens its outcomes. This study
assessed the association of ACE-I/ARB therapy with the development of severe
COVID-19.
METHODS: This multi-center, prospective study enrolled patients hospitalized for
COVID-19 and receiving one or more antihypertensive agents to manage either
hypertension or cardiovascular disease. ACE-I/ARB therapy associations with
severe COVID-19 on the day of hospitalization, intensive care unit (ICU)
admission, mechanical ventilation and in-hospital death on follow-up were tested
using a multivariate logistic regression model adjusted for age, obesity, and
chronic illnesses. The composite outcome of mechanical ventilation and death was
examined using the adjusted Cox multivariate regression model.
RESULTS: Of 338 enrolled patients, 245 (72.4%) were using ACE-I/ARB on the day
of hospital admission, and 197 continued ACE-I/ARB therapy during
hospitalization. Ninety-eight (29%) patients had a severe COVID-19, which was
not significantly associated with the use of ACE-I/ARB (OR 1.17, 95% CI
0.66-2.09; P = .57). Prehospitalization ACE-I/ARB therapy was not associated
with ICU admission, mechanical ventilation, or in-hospital death. Continuing
ACE-I/ARB therapy during hospitalization was associated with decreased mortality
(OR 0.22, 95% CI 0.073-0.67; P = .008). ACE-I/ARB use was not associated with
developing the composite outcome of mechanical ventilation and in-hospital death
(HR 0.95, 95% CI 0.51-1.78; P = .87) versus not using ACE-I/ARB.
CONCLUSION: Patients with hypertension or cardiovascular diseases receiving
ACE-I/ARB therapy are not at increased risk for severe COVID-19 on admission to
the hospital. ICU admission, mechanical ventilation, and mortality are not
associated with ACE-I/ARB therapy. Maintaining ACE-I/ARB therapy during
hospitalization for COVID-19 lowers the likelihood of death.
CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT4357535. BACKGROUND: The association of ACE inhibitors (ACEIs) and angiotensin II
receptor blockers (ARBs) with disease severity of patients with COVID-19 is
still unclear. We conducted a systematic review and meta-analysis to investigate
if ACEI/ARB use is associated with the risk of mortality and severe disease in
patients with COVID-19.
METHODS: We searched all available clinical studies that included patients with
confirmed COVID-19 who could be classified into an ACEI/ARB group and a
non-ACEI/ARB group up until 4 May 2020. A meta-analysis was performed, and
primary outcomes were all-cause mortality and severe disease.
RESULTS: ACEI/ARB use did not increase the risk of all-cause mortality both in
meta-analysis for 11 studies with 12 601 patients reporting ORs (OR=0.52 (95%
CI=0.37 to 0.72), moderate certainty of evidence) and in 2 studies with 8577
patients presenting HRs. For 12 848 patients in 13 studies, ACEI/ARB use was not
related to an increased risk of severe disease in COVID-19 (OR=0.68 (95% CI=0.44
to 1.07); I2=95%, low certainty of evidence).
CONCLUSIONS: ACEI/ARB therapy was not associated with increased risk of
all-cause mortality or severe manifestations in patients with COVID-19. ACEI/ARB
therapy can be continued without concern of drug-related worsening in patients
with COVID-19. Objective In this study, we aimed to compare the severity and outcomes in
hypertensive patients presenting with coronavirus disease 2019 (COVID-19) who
were taking angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin
receptor blockers (ARBs) and those who were on other antihypertensive drugs.
Methods This retrospective cohort study involved 182 hypertensive patients who
presented with COVID-19 infection. The study population comprised 91 patients
who were taking ACEIs/ARBs (group A) and 91 patients who were taking other
antihypertensive drugs such as β-blockers (BBs), calcium channel blockers
(CCBs), or thiazides (group B). All patients were provided the same type of
treatment for the management of COVID-19. We recorded the data related to
demographic and anthropometric variables as well as clinical symptoms during the
treatment period. Disease severity and hospital mortality were the primary study
endpoints. Results There was no significant difference in COVID-19-related
outcomes between the groups except for the severity of lung infiltration on
chest X-rays. There were 37 (41.1%) patients having >50% lung infiltration in
group A and 53 (58.2%) in group B (p-value: 0.02). Severe disease was diagnosed
in 37 (40.7%) patients in group A compared to 39 (42.7%) patients in group B
(p-value: 0.76). In-hospital mortality was noted in 17 (18.7%) patients in group
A and 22 (24.2%) patients in group B (p-value: 0.36). Conclusion Based on our
results, we did not find any significant association between the use of
ACEIs/ARBs and either the severity of COVID-19 infection necessitating admission
to ICU or in-hospital mortality. Introduction: Corona Virus disease 2019 (COVID-19) caused by the Severe Acute
Respiratory Syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic.
The aim of this study was to investigate the impact of being on an
Angiotensin-Converting Enzyme Inhibitors (ACEI) and/or Angiotensin Receptor
Blockers (ARB) on hospital admission, on the following COVID-19 outcomes:
disease severity, ICU admission, and mortality. Methods: The charts of all
patients consecutively diagnosed with COVID-19 from the 24th of February to the
16th of June of the year 2020 in Jaber Al-Ahmed Al-Sabah hospital in Kuwait were
checked. All related patient information and clinical data was retrieved from
the hospitals electronic medical record system. The primary outcome was COVID-19
disease severity defined as the need for Intensive Care Unit (ICU) admission.
Secondary outcome was mortality. Results: A total of 4,019 COVID-19 patients
were included, of which 325 patients (8.1%) used ACEI/ARB, users of ACEI/ARB
were found to be significantly older (54.4 vs. 40.5 years). ACEI/ARB users were
found to have more co-morbidities; diabetes (45.8 vs. 14.8%) and hypertension
(92.9 vs. 13.0%). ACEI/ARB use was found to be significantly associated with
greater risk of ICU admission in the unadjusted analysis [OR, 1.51 (95% CI:
1.04-2.19), p = 0.028]. After adjustment for age, gender, nationality, coronary
artery disease, diabetes and hypertension, ICU admission was found to be
inversely associated with ACEI use [OR, 0.57 (95% CI: 0.34-0.88), p = 0.01] and
inversely associated with mortality [OR, 0.56 (95% CI: 0.33-0.95), p = 0.032].
Conclusion: The current evidence in the literature supports continuation of
ACEI/ARB medications for patients with co-morbidities that acquire COVID-19
infection. Although, the protective effects of such medications on COVID-19
disease severity and mortality remain unclear, the findings of the present study
support the use of ACEI/ARB medication. Publisher: INTRODUCTION: Les antagonistes des récepteurs de l'angiotensine (ARA)
et/ou les inhibiteurs de l'enzyme de conversion de l'angiotensine (IECA)
feraient varier la mortalité liée à la COVID-19, mais il est possible que les
méta-analyses actuelles qui combinaient les résultats bruts et ajustés soient
invalidées du fait que les comorbidités sont plus fréquentes chez les
utilisateurs d'ARA/IECA.
MÉTHODES: Nous avons effectué des recherches dans les bases de données
PubMed/MEDLINE/Embase pour trouver des études de cohorte et des méta-analyses
qui portent sur la mortalité associée à un traitement préexistant par ARA/IECA
chez les patients hospitalisés atteints de la COVID-19. Nous avons utilisé la
métarégression à effets aléatoires pour calculer les rapports de cotes regroupés
de mortalité ajustés en fonction du déséquilibre de l’âge, du sexe, et de la
prévalence des maladies cardiovasculaires, de l'hypertension, du diabète sucré
et de l'insuffisance rénale chronique entre les utilisateurs et les
non-utilisateurs d'ARA/IECA dans le cadre de l’étude durant la synthèse des
données.
RÉSULTATS: Dans les 30 études portant sur 17 281 patients, 22 %, 68 %, 25 % et
11 % avaient respectivement une maladie cardiovasculaire, de l'hypertension, le
diabète sucré et de l'insuffisance rénale chronique. L'utilisation des ARA/IECA
a été associée à une mortalité significativement plus faible après avoir tenu
compte des facteurs confusionnels potentiels (rapport de cotes 0,77 [intervalle
de confiance à 95 % : 0,62, 0,96]). En revanche, la méta-analyse sur
l'utilisation des ARA/IECA n'a pas été associée de façon significative à la
mortalité lorsque toutes les études ont été combinées sans ajustement sur les
facteurs confusionnels (0,87 [intervalle de confiance à 95 % : 0,71, 1,08]).
CONCLUSIONS: L'utilisation des ARA/IECA a été associée à la diminution de la
mortalité au sein des cohortes de patients atteints de la COVID-19 après
l'ajustement en fonction de l’âge, du sexe, des maladies cardiovasculaires, de
l'hypertension, du diabète et de l'insuffisance rénale chronique. Les
méta-analyses non ajustées peuvent ne pas permettre de déterminer si les
ARA/IECA sont associés à la mortalité liée à la COVID-19 en raison du biais
d'indication. Author information:
(1)Department of Population Health Sciences, Division of Health System
Innovation and Research, University of Utah School of Medicine, Salt Lake City,
UT, United States of America.
(2)Department of Medicine, Renal-Electrolyte and Hypertension Division, Perelman
School of Medicine at the University of Pennsylvania, Philadelphia, PA, United
States of America.
(3)Department of Biostatistics, Epidemiology, and Informatics, Perelman School
of Medicine, University of Pennsylvania, Philadelphia, PA, United States of
America.
(4)George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake
City, UT, United States of America.
(5)Department of Internal Medicine, University of Utah School of Medicine, Salt
Lake City, UT, United States of America.
(6)Department of Medicine, Division of Cardiology, University of Utah School of
Medicine, Salt Lake City, UT, United States of America.
(7)Department of Pediatrics, Section of Nephrology, Brenner Children's Hospital,
Wake Forest School of Medicine, Winston Salem, NC, United States of America.
(8)Division of Public Health Sciences, Department of Epidemiology and
Prevention, Wake Forest School of Medicine, Winston Salem, NC, United States of
America.
(9)Department of Medicine, Division of Cardiology, Perelman School of Medicine,
University of Pennsylvania, Philadelphia, PA, United States of America.
(10)Department of Pharmacotherapy and Translational Research, University of
Florida College of Pharmacy, Gainesville, FL, United States of America.
(11)Department of Medicine, University of Florida, College of Medicine,
Gainesville, FL, United States of America.
(12)Institute for Health Research, Kaiser Permanente Colorado, Aurora, CO,
United States of America.
(13)Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health,
Baltimore, MD.
(14)Department of Public Health; University of Massachusetts Lowell, Lowell, MA,
United States of America.
(15)Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA, United States
of America.
(16)Department of Medicine, Division of Cardiology, Northwestern University
Feinberg School of Medicine, Chicago, IL, United States of America.
(17)Department of Pharmacology and Experimental Therapeutics, Boston University
School of Medicine, Boston, MA, United States of America.
(18)MedStar Washington Hospital Center, Washington, DC, United States of
America. Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor
blockers (ARBs) share a target receptor with severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2). The use of ACEIs/ARBs may cause
angiotensin-converting enzyme 2 receptor upregulation, facilitating the entry of
SARS-CoV-2 into host cells. There is concern that the use of ACEIs/ARBs could
increase the risks of severe COVID-19 and mortality. The impact of discontinuing
these drugs in patients with COVID-19 remains uncertain. We aimed to assess the
association between the use of ACEIs/ARBs and the risks of mortality and severe
disease in patients with COVID-19. A systematic search was performed in PubMed,
EMBASE, Cochrane Library, and MedRxiv.org from December 1, 2019, to June 20,
2020. We also identified additional citations by manually searching the
reference lists of eligible articles. Forty-two observational studies including
63,893 participants were included. We found that the use of ACEIs/ARBs was not
significantly associated with a reduction in the relative risk of all-cause
mortality [odds ratio (OR) = 0.87, 95% confidence interval (95% CI) = 0.75-1.00;
I 2 = 57%, p = 0.05]. We found no significant reduction in the risk of severe
disease in the ACEI subgroup (OR = 0.95, 95% CI = 0.88-1.02, I 2 = 50%, p =
0.18), the ARB subgroup (OR = 1.03, 95% CI = 0.94-1.13, I 2 = 62%, p = 0.48), or
the ACEI/ARB subgroup (OR = 0.83, 95% CI = 0.65-1.08, I 2 = 67%, p = 0.16).
Moreover, seven studies showed no significant difference in the duration of
hospitalization between the two groups (mean difference = 0.33, 95% CI = -1.75
to 2.40, p = 0.76). In conclusion, the use of ACEIs/ARBs appears to not have a
significant effect on mortality, disease severity, or duration of
hospitalization in COVID-19 patients. On the basis of the findings of this
meta-analysis, there is no support for the cessation of treatment with ACEIs or
ARBs in patients with COVID-19. OBJECTIVE: Although recent evidence suggests no increased risk of severe
COVID-19 outcomes associated with angiotensin-converting enzyme inhibitors
(ACEIs) or angiotensin receptor blockers (ARBs) use, the relationship is less
clear among patients with hypertension and diverse racial/ethnic groups. This
study evaluates the risk of hospitalization and mortality among patients with
hypertension and COVID-19 in a large US integrated healthcare system.
METHODS: Patients with hypertension and COVID-19 (between March 1- September 1,
2020) on ACEIs or ARBs were compared with patients on other frequently used
antihypertensive medications.
RESULTS: Among 14,129 patients with hypertension and COVID-19 infection (mean
age 60 years, 48% men, 58% Hispanic), 21% were admitted to the hospital within
30 days of COVID-19 infection. Of the hospitalized patients, 24% were admitted
to intensive care units, 17% required mechanical ventilation, and 10% died
within 30 days of COVID-19 infection. Exposure to ACEIs or ARBs prior to
COVID-19 infection was not associated with an increased risk of hospitalization
or all-cause mortality (rate ratios for ACEIs vs other antihypertensive
medications = 0.98, 95% CI: 0.88, 1.08; ARBs vs others = 1.00, 95% CI: 0.90,
1.11) after applying inverse probability of treatment weights. These
associations were consistent across racial/ethnic groups. Use of ACEIs or ARBs
during hospitalization was associated with a lower risk of all-cause mortality
(odds ratios for ACEIs or ARBs vs others = 0.50, 95% CI: 0.34, 0.72).
CONCLUSION: Our study findings support continuation of ACEI or ARB use for
patients with hypertension during the COVID-19 pandemic and after COVID-19
infection. INTRODUCTION: There is significant interest in the use of angiotensin converting
enzyme inhibitors (ACE-I) and angiotensin II receptor blockers (ARB) in
coronavirus disease 2019 (COVID-19) and concern over potential adverse effects
since these medications upregulate the severe acute respiratory syndrome
coronavirus 2 host cell entry receptor ACE2. Recent studies on ACE-I and ARB in
COVID-19 were limited by excluding outpatients, excluding patients by age,
analyzing ACE-I and ARB together, imputing missing data, and/or diagnosing
COVID-19 by chest computed tomography without definitive reverse transcription
polymerase chain reaction (RT-PCR), all of which are addressed here.
METHODS: We performed a retrospective cohort study of 1023 COVID-19 patients
diagnosed by RT-PCR at Stanford Hospital through April 8, 2020 with a minimum
follow-up time of 14 days to investigate the association between ACE-I or ARB
use with outcomes.
RESULTS: Use of ACE-I or ARB medications was not associated with increased risk
of hospitalization, intensive care unit admission, or death. Compared to
patients with charted past medical history, there was a lower risk of
hospitalization for patients on ACE-I (odds ratio (OR) 0.43; 95% confidence
interval (CI) 0.19-0.97; P = 0.0426) and ARB (OR 0.39; 95% CI 0.17-0.90; P =
0.0270). Compared to patients with hypertension not on ACE-I or ARB, patients on
ARB medications had a lower risk of hospitalization (OR 0.09; 95% CI 0.01-0.88;
P = 0.0381).
CONCLUSIONS: These findings suggest that the use of ACE-I and ARB is not
associated with adverse outcomes and may be associated with improved outcomes in
COVID-19, which is immediately relevant to care of the many patients on these
medications. |
Which small molecules inhibit the c-Myc/Max dimerization? | Mycros are the first inhibitors of c-Myc/Max dimerization, which have been demonstrated to inhibit DNA binding of c-Myc with preference over other dimeric transcription factors in vitroMost Myc inhibitors prevent the association between Myc and its obligate heterodimerization partner Max via their respective bHLH-ZIP domainsPreviously we showed that two c-Myc-Max inhibitors, 10058-F4 and 10074-G5, bound to distinct ID regions of the monomeric c-Myc bHLHZip domainWe tested the efficacy of Mycro3, a small-molecule inhibitor of Myc-Max dimerizationIn a fluorescence polarization screen for the MYC-MAX interaction, we have identified a novel small-molecule inhibitor of MYC, KJ-Pyr-9, from a Kröhnke pyridine libraryWe have previously demonstrated that the small molecule 10058-F4, known to bind to the c-MYC bHLHZip dimerization domain and inhibiting the c-MYC/MAX interaction, also interferes with the MYCN/MAX dimerization in vitro and imparts anti-tumorigenic effects in neuroblastoma tumor models with MYCN overexpressionWe developed a series of small-molecule MYC inhibitors that engage MYC inside cells, disrupt MYC/MAX dimers, and impair MYC-driven gene expression.Inhibition of MYC/MAX dimerization by a small-molecule antagonist (IIA6B17) has been shown to interfere with MYC-induced transformation of chick embryo fibroblasts, suggesting that the functional inhibitors of the MYC family of oncoproteins have potential as therapeutic agents. | OBJECTIVE: The protooncogene c-Myc plays an important role in the control of
cell proliferation, apoptosis, and differentiation, and its aberrant expression
is frequently seen in multiple human cancers, including acute myeloid leukemia
(AML). As c-Myc heterodimerizes with Max to transactivate downstream target
genes in leukemogenesis. Inhibition of the c-Myc/Max heterodimerization by the
recently identified small-molecule compound, 10058-F4, might be a novel
antileukemic strategy.
MATERIALS AND METHODS: HL-60, U937, and NB4 cells and primary AML cells were
used to examine the effects of 10058-F4 on apoptosis and myeloid
differentiation.
RESULTS: We showed that 10058-F4 arrested AML cells at G0/G1 phase,
downregulated c-Myc expression and upregulated CDK inhibitors, p21 and p27.
Meanwhile, 10058-F4 induced apoptosis through activation of mitochondrial
pathway shown by downregulation of Bcl-2, upregulation of Bax, release of
cytoplasmic cytochrome C, and cleavage of caspase 3, 7, and 9. Furthermore,
10058-F4 also induced myeloid differentiation, possibly through activation of
multiple transcription factors. Similarly, 10058-F4-induced apoptosis and
differentiation could also be observed in primary AML cells.
CONCLUSION: Our study has shown that inhibition of c-Myc/Max dimerization with
small-molecule inhibitors affects multiple cellular activities in AML cells and
represents a potential antileukemic approach. Inhibition of MYC/MAX dimerization by a small-molecule antagonist (IIA6B17) has
been shown to interfere with MYC-induced transformation of chick embryo
fibroblasts, suggesting that the functional inhibitors of the MYC family of
oncoproteins have potential as therapeutic agents. In the present study, a
functional MYC reporter gene assay has been developed, using a luciferase gene
construct under the control of the ornithine decarboxylase (ODC) gene promoter.
This luciferase gene construct has been stably transfected into the MYCN
amplified neuroblastoma cell line (NGP) and MYCC-overexpressed neuroepithelioma
cell line (NB100). After exposure of the cell lines to IIA6B17 for 24 h, a
significant reduction of luciferase activity was only observed in the NB100
cells, with IC50 values of approximately 28+/-9 microM, indicating that IIA6B17
has cell line-specific activity which may be selective for individual members of
the MYC family. Deregulation of the c-Myc transcription factor is involved in many types of
cancer, making this oncoprotein an attractive target for drug discovery. One
approach to its inhibition has been to disrupt the dimeric complex formed
between its basic helix-loop-helix leucine zipper (bHLHZip) domain and a similar
domain on its dimerization partner, Max. As monomers, bHLHZip proteins are
intrinsically disordered (ID). Previously we showed that two c-Myc-Max
inhibitors, 10058-F4 and 10074-G5, bound to distinct ID regions of the monomeric
c-Myc bHLHZip domain. Here, we use circular dichroism, fluorescence
polarization, and NMR to demonstrate the presence of an additional binding site
located between those for 10058-F4 and 10074-G5. All seven of the originally
identified Myc inhibitors are shown to bind to one of these three discrete sites
within the 85-residue bHLHZip domain of c-Myc. These binding sites are composed
of short contiguous stretches of amino acids that can selectively and
independently bind small molecules. Inhibitor binding induces only local
conformational changes, preserves the overall disorder of c-Myc, and inhibits
dimerization with Max. NMR experiments further show that binding at one site on
c-Myc affects neither the affinity nor the structural changes taking place upon
binding to the other sites. Rather, binding can occur simultaneously and
independently on the three identified sites. Our results suggest the widespread
existence of peptide regions prone to small-molecule binding within ID domains.
A rational and generic approach to the inhibition of protein-protein
interactions involving ID proteins may therefore be possible through the
targeting of ID sequence. The c-Myc (Myc) oncoprotein is a high-value therapeutic target given that it is
deregulated in multiple types of cancer. However, potent small molecule
inhibitors of Myc have been difficult to identify, particularly those whose
mechanism relies on blocking the association between Myc and its obligate
heterodimerization partner, Max. We have recently reported a structure-activity
relationship study of one such small molecule, 10074-G5, and generated an
analog, JY-3-094, with significantly improved ability to prevent or disrupt the
association between recombit Myc and Max proteins. However, JY-3094
penetrates cells poorly. Here, we show that esterification of a critical
para-carboxylic acid function of JY-3-094 by various blocking groups
significantly improves cellular uptake although it impairs the ability to
disrupt Myc-Max association in vitro. These pro-drugs are highly concentrated
within cells where JY-3-094 is then generated by the action of esterases.
However, the pro-drugs are also variably susceptible to extracellular esterases,
which can deplete extracellular reservoirs. Furthermore, while JY-3-094 is
retained by cells for long periods of time, much of it is compartmentalized
within the cytoplasm in a form that appears to be less available to interact
with Myc. Our results suggest that persistently high extracellular levels of
pro-drug, without excessive susceptibility to extracellular esterases, are
critical to establishing and maintaining intracellular levels of JY-3-094 that
are sufficient to provide for long-term inhibition of Myc-Max association.
Analogs of JY-3-094 appear to represent promising small molecule Myc inhibitors
that warrant further optimization. Members of the MYC family are the most frequently deregulated oncogenes in human
cancer and are often correlated with aggressive disease and/or poorly
differentiated tumors. Since patients with MYCN-amplified neuroblastoma have a
poor prognosis, targeting MYCN using small molecule inhibitors could represent a
promising therapeutic approach. We have previously demonstrated that the small
molecule 10058-F4, known to bind to the c-MYC bHLHZip dimerization domain and
inhibiting the c-MYC/MAX interaction, also interferes with the MYCN/MAX
dimerization in vitro and imparts anti-tumorigenic effects in neuroblastoma
tumor models with MYCN overexpression. Our previous work also revealed that
MYCN-inhibition leads to mitochondrial dysfunction resulting in accumulation of
lipid droplets in neuroblastoma cells. To expand our understanding of how small
molecules interfere with MYCN, we have now analyzed the direct binding of
10058-F4, as well as three of its analogs; #474, #764 and 10058-F4(7RH), one
metabolite C-m/z 232, and a structurally unrelated c-MYC inhibitor 10074-G5, to
the bHLHZip domain of MYCN. We also assessed their ability to induce apoptosis,
neurite outgrowth and lipid accumulation in neuroblastoma cells. Interestingly,
all c-MYC binding molecules tested also bind MYCN as assayed by surface plasmon
resoce. Using a proximity ligation assay, we found reduced interaction
between MYCN and MAX after treatment with all molecules except for the 10058-F4
metabolite C-m/z 232 and the non-binder 10058-F4(7RH). Importantly, 10074-G5 and
10058-F4 were the most efficient in inducing neuronal differentiation and lipid
accumulation in MYCN-amplified neuroblastoma cells. Together our data
demonstrate MYCN-binding properties for a selection of small molecules, and
provide functional information that could be of importance for future
development of targeted therapies against MYCN-amplified neuroblastoma. c-Myc is a basic helix-loop-helix-leucine zipper (bHLH-ZIP) transcription factor
that is responsible for the transcription of a wide range of target genes
involved in many cancer-related cellular processes. Over-expression of c-Myc has
been observed in, and directly contributes to, a variety of human cancers
including those of the hematopoietic system, lung, prostate and colon. To become
transcriptionally active, c-Myc must first dimerize with Myc-associated factor X
(Max) via its own bHLH-ZIP domain. A proven strategy towards the inhibition of
c-Myc oncogenic activity is to interfere with the structural integrity of the
c-Myc-Max heterodimer. The small molecule 10074-G5 is an inhibitor of c-Myc-Max
dimerization (IC50 =146 μM) that operates by binding and stabilizing c-Myc in
its monomeric form. We have identified a congener of 10074-G5, termed 3jc48-3
(methyl
4'-methyl-5-(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)-[1,1'-biphenyl]-3-carboxylate),
that is about five times as potent (IC50 =34 μM) at inhibiting c-Myc-Max
dimerization as the parent compound. 3jc48-3 exhibited an approximate twofold
selectivity for c-Myc-Max heterodimers over Max-Max homodimers, suggesting that
its mode of action is through binding c-Myc. 3jc48-3 inhibited the proliferation
of c-Myc-over-expressing HL60 and Daudi cells with single-digit micromolar IC50
values by causing growth arrest at the G0 /G1 phase. Co-immunoprecipitation
studies indicated that 3jc48-3 inhibits c-Myc-Max dimerization in cells, which
was further substantiated by the specific silencing of a c-Myc-driven luciferase
reporter gene. Finally, 3jc48-3's intracellular half-life was >17 h.
Collectively, these data demonstrate 3jc48-3 to be one of the most potent,
cellularly active and stable c-Myc inhibitors reported to date. In a fluorescence polarization screen for the MYC-MAX interaction, we have
identified a novel small-molecule inhibitor of MYC, KJ-Pyr-9, from a Kröhnke
pyridine library. The Kd of KJ-Pyr-9 for MYC in vitro is 6.5 ± 1.0 nM, as
determined by backscattering interferometry; KJ-Pyr-9 also interferes with
MYC-MAX complex formation in the cell, as shown in a protein fragment
complementation assay. KJ-Pyr-9 specifically inhibits MYC-induced oncogenic
transformation in cell culture; it has no or only weak effects on the oncogenic
activity of several unrelated oncoproteins. KJ-Pyr-9 preferentially interferes
with the proliferation of MYC-overexpressing human and avian cells and
specifically reduces the MYC-driven transcriptional signature. In vivo, KJ-Pyr-9
effectively blocks the growth of a xenotransplant of MYC-amplified human cancer
cells. BACKGROUND: Pancreatic ductal adenocarcinoma (PDA) is frequently driven by
oncogenic KRAS(KRAS*) mutations. We developed a mouse model of KRAS*-induced PDA
and, based on genetic results demonstrating that KRAS* tumorigenicity depends on
Myc activity, we evaluated the therapeutic potential of an orally administered
anti-Myc drug.
METHODS: We tested the efficacy of Mycro3, a small-molecule inhibitor of Myc-Max
dimerization, in the treatment of mouse PDA (n = 9) and also of xenografts of
human pancreatic cancer cell lines (NOD/SCID mice, n = 3-12). Tumor responses to
the drug were evaluated by PET/CT imaging, and histological,
immunohistochemical, molecular and microarray analyses. The Student's t test was
used for differences between groups. All statistical tests were two-sided.
RESULTS: Transgenic overexpression of KRAS* in the pancreas resulted in
pancreatic intraepithelial neoplasia in two-week old mice, which developed
invasive PDA a week later and became moribund at one month. However, this
aggressive form of pancreatic tumorigenesis was effectively prevented by genetic
ablation of Myc specifically in the pancreas. We then treated moribund,
PDA-bearing mice daily with the Mycro3 Myc-inhibitor. The mice survived until
killed at two months. PET/CT image analysis (n = 5) demonstrated marked
shrinkage of PDA, while immunohistochemical analyses showed an increase in
cancer cell apoptosis and reduction in cell proliferation (treated/untreated
proliferation index ratio: 0.29, P < .001, n = 3, each group). Tumor growth was
also drastically attenuated in Mycro3-treated NOD/SCID mice (n = 12) carrying
orthotopic or heterotopic xenografts of human pancreatic cancer cells (eg, mean
tumor weight ± SD of treated heterotopic xenografts vs vehicle-treated controls:
15.2±5.8 mg vs 230.2±43.9 mg, P < .001).
CONCLUSION: These results provide strong justification for eventual clinical
evaluation of anti-Myc drugs as potential chemotherapeutic agents for the
treatment of PDA. Author information:
(1)David H. Koch Institute for Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, MA 02142, USA; Department of Biological
Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA;
MIT Center for Precision Cancer Medicine, Massachusetts Institute of Technology,
Cambridge, MA 02142, USA.
(2)Division of Oncology, Departments of Medicine and Pathology Stanford School
of Medicine, Stanford, CA 94305, USA.
(3)David H. Koch Institute for Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, MA 02142, USA; Department of Biological
Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
(4)Department of Molecular and Human Genetics and Verna & Marrs McLean
Department of Biochemistry and Molecular Biology, Baylor College of Medicine,
Houston, TX 77030, USA.
(5)David H. Koch Institute for Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, MA 02142, USA; Department of Biological
Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA;
Kronos Bio, Inc., Cambridge, MA 02139, USA.
(6)Division of Hematology, Department of Medicine, Brigham and Women's Hospital,
Harvard Medical School, Boston, MA 02115, USA; Department of Medical Oncology,
Dana-Farber Cancer Institute, Boston, MA 02215, USA; Broad Institute of MIT and
Harvard, Cambridge, MA 02142, USA.
(7)Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
(8)David H. Koch Institute for Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, MA 02142, USA; BioMicro Center,
Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
(9)David H. Koch Institute for Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, MA 02142, USA.
(10)David H. Koch Institute for Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, MA 02142, USA; Department of Biological
Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA;
Division of Pediatric Hematology/Oncology, Boston Children's Hospital, Boston,
MA 02115, USA.
(11)Department of Molecular and Human Genetics and Verna & Marrs McLean
Department of Biochemistry and Molecular Biology, Baylor College of Medicine,
Houston, TX 77030, USA; Therapeutic Innovation Center, Baylor College of
Medicine, Houston, TX 77030, USA.
(12)David H. Koch Institute for Integrative Cancer Research, Massachusetts
Institute of Technology, Cambridge, MA 02142, USA; Department of Biological
Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA;
MIT Center for Precision Cancer Medicine, Massachusetts Institute of Technology,
Cambridge, MA 02142, USA; Broad Institute of MIT and Harvard, Cambridge, MA
02142, USA. Electronic address: [email protected]. Author information:
(1)Department of Urology, Northwestern University Feinberg School of Medicine,
Chicago, IL 60611, USA.
(2)Center for Molecular Innovation and Drug Discovery, Northwestern University,
Evanston, IL 60208, USA.
(3)Center for Developmental Therapeutics, Northwestern University, Evanston, IL
60208, USA.
(4)Division of Reproductive Science in Medicine, Department of OB/GYN,
Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
(5)Division of Reproductive Science in Medicine, Department of OB/GYN,
Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA; The
Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg
School of Medicine, Chicago, IL 60611, USA; Department of Pharmacology,
Northwestern University Feinberg School of Medicine, Chicago IL 60611, USA.
(6)Center for Molecular Innovation and Drug Discovery, Northwestern University,
Evanston, IL 60208, USA; Department of Pharmacology, Northwestern University
Feinberg School of Medicine, Chicago IL 60611, USA.
(7)Center for Molecular Innovation and Drug Discovery, Northwestern University,
Evanston, IL 60208, USA; The Robert H. Lurie Comprehensive Cancer Center,
Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA;
Department of Pharmacology, Northwestern University Feinberg School of Medicine,
Chicago IL 60611, USA.
(8)Department of Urology, Northwestern University Feinberg School of Medicine,
Chicago, IL 60611, USA; The Robert H. Lurie Comprehensive Cancer Center,
Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA;
Department of Pathology, Northwestern University Feinberg School of Medicine,
Chicago, IL 60611, USA. Electronic address: [email protected]. |
Which models are used for predicting disease progression in Duchenne Muscular Dystrophy? | Longitudinal changes in biomarkers were modeled with a cumulative distribution function using a nonlinear mixed-effects approach. | We used biochemical and clinical variables to develop a method to predict the
expected duration of independent walking following surgery and bracing in
patients with Duchenne muscular dystrophy. Data from the records of fifty
patients were analyzed by linear and multiple regression. The most useful
factors, applied in combination, in predicting the duration of walking ability
after bracing were: percentage of residual muscle strength, vital capacity,
creatinine coefficient, motivation of the patient at the time of bracing, and
decrease in creatinine coefficient in the two years prior to bracing. This
system uses readily available variables to predict the response to bracing in
patients with Duchenne muscular dystrophy. Improvement in the criteria for the
selection of patients for surgery and bracing is important in view of the
economic cost as well as the demands on the time and energy of these children
and their parents. The 6-minute walk test (6MWT) is used as a clinical endpoint to evaluate drug
efficacy in Duchenne Muscular Dystrophy (DMD) trials. A model was developed
using digitized 6MWT data that estimated two slopes and two intercepts to
characterize 6MWT improvement during development and 6MWT decline. Mean baseline
6MWT was 362 (±87) meters. The model predicted an improvement at a rate of 20
meters/year (95% confidence interval (CI) = 9.4-30) up until 10 years old (95%
CI = 6.78-13.1), and then a decline at a rate of 85 meters/year (95%
CI = 72-98). Interpatient slope variability for improvement and decline were
similar at 21.9 percentage of coefficient of variation (%CV) and 23.3%CV,
respectively. Model simulations using age demographics from a previous DMD
natural history study could reasonably predict the trend in improvement and
decline in the 6MWT. This model can be used to quantitate individual patient
trajectories, identify prognostic factors for disease progression, and evaluate
drug effect. INTRODUCTION: Duchenne muscular dystrophy (DMD) leads to a progressive
deterioration of the mus cle function and premature death. There are no
longitudinal studies on the course of this pathology in Chile.
OBJECTIVE: To determine survival between the years 1993-2013, divided into two
periods (1993-2002 and 2003-2013), and the effect of social determits in
patients with DMD admitted in Teleton Institutes of Chile (TI).
PATIENTS AND METHOD: Prospective follow-up study in a clinical series of 462
patients with DMD. The information was obtained by searching for patients with
DMD in OLAP cube (Online Analytical Processing). From the clinical records of
the TI of Santiago, the variables corresponding to the diagnostic method, stage
of DMD described in terms of muscle de terioration and function according to
Swinyard classification were recorded; existence and type of tests that conclude
the diagnosis and, in the cases reported, the existence of family history.
Kaplan Meier survival analysis was applied, where global survival was defined
between birth and age of death. The determit factors analyzed were estimated
through the Cox-Snell's proportional risk model.
RESULTS: Survival at 20 years of age from TI entry was 51.7% (CI95%: 45.1-57.8),
48.5% in the period 1993-2002 and 72.8% between 2003-2013. The percentage of
survival at the same age according to socioeconomic status (SES) was 82% in high
SES, 67% in middle SES, and 42% in low SES, with a statistically significant
difference between high and middle SES in relation to extreme poverty. Ac
cording to country areas, the survival was close to 75 % at 17 years of age.
CONCLUSIONS: The survival information from patients with DMD from childhood to
adult life is valuable for predicting the clinical course of the disease with
the current medical care. There is evidence of improvement in the probability of
survival at the age of 20 and marked inequity according to the socioeconomic
variable. OBJECTIVE: To quantify disease progression in individuals with Duchenne muscular
dystrophy (DMD) using magnetic resoce biomarkers of leg muscles.
METHODS: MRI and magnetic resoce spectroscopy (MRS) biomarkers were acquired
from 104 participants with DMD and 51 healthy controls using a prospective
observational study design with patients with DMD followed up yearly for up to 6
years. Fat fractions (FFs) in vastus lateralis and soleus muscles were
determined with 1H MRS. MRI quantitative T2 (qT2) values were measured for 3
muscles of the upper leg and 5 muscles of the lower leg. Longitudinal changes in
biomarkers were modeled with a cumulative distribution function using a
nonlinear mixed-effects approach.
RESULTS: MRS FF and MRI qT2 increased with DMD disease duration, with the
progression time constants differing markedly between individuals and across
muscles. The average age at half-maximal muscle involvement (μ) occurred 4.8
years earlier in vastus lateralis than soleus, and these measures were strongly
associated with loss-of-ambulation age. Corticosteroid treatment was found to
delay μ by 2.5 years on average across muscles, although there were marked
differences between muscles with more slowly progressing muscles showing larger
delay.
CONCLUSIONS: MRS FF and MRI qT2 provide sensitive noninvasive measures of DMD
progression. Modeling changes in these biomarkers across multiple muscles can be
used to detect and monitor the therapeutic effects of corticosteroids on disease
progression and to provide prognostic information on functional outcomes. This
modeling approach provides a method to transform these MRI biomarkers into
well-understood metrics, allowing concise summaries of DMD disease progression
at individual and population levels.
CLINICALTRIALSGOV IDENTIFIER: NCT01484678. Early clinical trials of therapies to treat Duchenne muscular dystrophy (DMD), a
fatal genetic X-linked pediatric disease, have been designed based on the
limited understanding of natural disease progression and variability in clinical
measures over different stages of the continuum of the disease. The objective
was to inform the design of DMD clinical trials by developing a disease
progression model-based clinical trial simulation (CTS) platform based on
measures commonly used in DMD trials. Data were integrated from past studies
through the Duchenne Regulatory Science Consortium founded by the Critical Path
Institute (15 clinical trials and studies, 1505 subjects, 27,252 observations).
Using a nonlinear mixed-effects modeling approach, longitudinal dynamics of five
measures were modeled (NorthStar Ambulatory Assessment, forced vital capacity,
and the velocities of the following three timed functional tests: time to stand
from supine, time to climb 4 stairs, and 10 meter walk-run time). The models
were validated on external data sets and captured longitudinal changes in the
five measures well, including both early disease when function improves as a
result of growth and development and the decline in function in later stages.
The models can be used in the CTS platform to perform trial simulations to
optimize the selection of inclusion/exclusion criteria, selection of measures,
and other trial parameters. The data sets and models have been reviewed by the
US Food and Drug Administration and the European Medicines Agency; have been
accepted into the Fit-for-Purpose and Qualification for Novel Methodologies
pathways, respectively; and will be submitted for potential endorsement by both
agencies. |
What links muscle cellular pathways to ALS? | Changes to muscle cellular pathways may occur downstream of motor neuron pathology in ALS. Genetic changes to pathways that are important to muscle function may also be causal of the disease. In addition, changes to the muscle may be responsible for motor neuron death. Pathological changes occur in muscle before disease onset and independent from MN degeneration, and the muscle may release toxic elements, such as via extracellular vesicle secretion. Muscle metabolism and mitochondrial activity, RNA processing, tissue-resident stem cell function responsible for muscle regeneration, and proteostasis that regulates muscle mass in adulthood, are all deregulated in ALS. There may also be a link between motor neuron death, the immune system, and muscle cells, as muscle-resident glial cells have been shown to activate upon nerve injury. Muscle-restricted expression of a localized insulin-like growth factor Igf-1 isoform maintained muscle integrity and enhanced satellite cell activity in SOD1(G93A) transgenic mice. | Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease
characterized by a selective degeneration of motor neurons, atrophy, and
paralysis of skeletal muscle. Although a significant proportion of familial ALS
results from a toxic gain of function associated with domit SOD1 mutations,
the etiology of the disease and its specific cellular origins have remained
difficult to define. Here, we show that muscle-restricted expression of a
localized insulin-like growth factor (Igf) -1 isoform maintained muscle
integrity and enhanced satellite cell activity in SOD1(G93A) transgenic mice,
inducing calcineurin-mediated regenerative pathways. Muscle-specific expression
of local Igf-1 (mIgf-1) isoform also stabilized neuromuscular junctions, reduced
inflammation in the spinal cord, and enhanced motor neuronal survival in
SOD1(G93A) mice, delaying the onset and progression of the disease. These
studies establish skeletal muscle as a primary target for the domit action of
inherited SOD1 mutation and suggest that muscle fibers provide appropriate
factors, such as mIgf-1, for neuron survival. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized
by loss of motor neurons, denervation of target muscles, muscle atrophy, and
paralysis. Understanding ALS pathogenesis may require a fuller understanding of
the bidirectional signaling between motor neurons and skeletal muscle fibers at
neuromuscular synapses. Here, we show that a key regulator of this signaling is
miR-206, a skeletal muscle-specific microRNA that is dramatically induced in a
mouse model of ALS. Mice that are genetically deficient in miR-206 form normal
neuromuscular synapses during development, but deficiency of miR-206 in the ALS
mouse model accelerates disease progression. miR-206 is required for efficient
regeneration of neuromuscular synapses after acute nerve injury, which probably
accounts for its salutary effects in ALS. miR-206 mediates these effects at
least in part through histone deacetylase 4 and fibroblast growth factor
signaling pathways. Thus, miR-206 slows ALS progression by sensing motor neuron
injury and promoting the compensatory regeneration of neuromuscular synapses. INTRODUCTION: Amyotrophic lateral sclerosis (ALS), a degenerative disorder of
the central nervous system, manifests as progressive weakening of muscles. The
diagnosis and prognosis of ALS are often unclear, so useful biomarkers are
needed.
METHODS: Total proteins were extracted from muscle samples from 36 ALS, 17
spinal muscular atrophy (SMA), and 36 normal individuals. The expression levels
of 134 proteins and phosphoproteins were assessed using protein pathway array
analysis.
RESULTS: Seventeen proteins were differentially expressed between ALS and normal
muscle, and 9 proteins were differentially expressed between ALS and SMA muscle.
The low-level expression of Akt and Factor XIIIB correlates with unfavorable
survival, and the risk score calculated based on these proteins predicts the
survival of each individual patient.
CONCLUSIONS: Some proteins could be selected as clinically useful biomarkers.
Specifically, Akt and Factor XIIIB were found to be promising biomarkers for
estimating prognosis in ALS. Accumulation of abnormal protein inclusions is implicated in motor neuron
degeneration in amyotrophic lateral sclerosis (ALS). Autophagy, an intracellular
process targeting misfolded proteins and damaged organelles for lysosomal
degradation, plays crucial roles in survival and diseased conditions. Efforts
were made to understand the role of autophagy in motor neuron degeneration and
to target autophagy in motor neuron for ALS treatment. However, results were
quite contradictory. Possible autophagy defects in other cell types may also
complicate the results. Here, we examined autophagy activity in skeletal muscle
of an ALS mouse model G93A. Through overexpression of a fluorescent protein
LC3-RFP, we found a basal increase in autophagosome formation in G93A muscle
during disease progression when the mice were on a regular diet. As expected, an
autophagy induction procedure (starvation plus colchicine) enhanced autophagy
flux in skeletal muscle of normal mice. However, in response to the same
autophagy induction procedure, G93A muscle showed significant reduction in the
autophagy flux. Immunoblot analysis revealed that increased cleaved caspase-3
associated with apoptosis was linked to the cleavage of several key proteins
involved in autophagy, including Beclin-1, which is an essential molecule
connecting autophagy and apoptosis pathways. Taking together, we provide the
evidence that the cytoprotective autophagy pathway is suppressed in G93A
skeletal muscle and this suppression may link to the enhanced apoptosis during
ALS progression. The abnormal autophagy activity in skeletal muscle likely
contributes muscle degeneration and disease progression in ALS. Mutations in Cu/Zn superoxide dismutase (SOD1) are one of the genetic causes of
Amyotrophic Lateral Sclerosis (ALS). Although the primary symptom of ALS is
muscle weakness, the link between SOD1 mutations, cellular dysfunction and
muscle atrophy and weakness is not well understood. The purpose of this study
was to characterize cellular markers of ER stress in skeletal muscle across the
lifespan of G93A*SOD1 (ALS-Tg) mice. Muscles were obtained from ALS-Tg and
age-matched wild type (WT) mice at 70d (pre-symptomatic), 90d and 120-140d
(symptomatic) and analyzed for ER stress markers. In white gastrocnemius (WG)
muscle, ER stress sensors PERK and IRE1α were upregulated ~2-fold at 70d and
remained (PERK) or increased further (IRE1α) at 120-140d. Phospho-eIF2α, a
downstream target of PERK and an inhibitor of protein translation, was increased
by 70d and increased further to 12.9-fold at 120-140d. IRE1α upregulation leads
to increased splicing of X-box binding protein 1 (XBP-1) to the XBP-1s isoform.
XBP-1s transcript was increased at 90d and 120-140d indicating activation of
IRE1α signaling. The ER chaperone/heat shock protein Grp78/BiP was upregulated
2-fold at 70d and 90d and increased to 6.1-fold by 120-140d. The
ER-stress-specific apoptotic signaling protein CHOP was upregulated 2-fold at
70d and 90d and increased to 13.3-fold at 120-140d indicating progressive
activation of an apoptotic signal in muscle. There was a greater increase in
Grp78/BiP and CHOP in WG vs. the more oxidative red gastrocnemius (RG) ALS-Tg at
120-140d indicating greater ER stress and apoptosis in fast glycolytic muscle.
These data show that the ER stress response is activated in skeletal muscle of
ALS-Tg mice by an early pre-symptomatic age and increases with disease
progression. These data suggest a mechanism by which myocellular ER stress leads
to reduced protein translation and contributes to muscle atrophy and weakness in
ALS. Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease
characterized by progressive motor dysfunction and loss of large motor neurons
in the spinal cord and brain stem. While much research has focused on mechanisms
of motor neuron cell death in the spinal cord, degenerative processes in
skeletal muscle and neuromuscular junctions (NMJs) are also observed early in
disease development. Although recent studies support the potential therapeutic
benefits of targeting the skeletal muscle in ALS, relatively little is known
about inflammation and glial responses in skeletal muscle and near NMJs, or how
these responses contribute to motor neuron survival, neuromuscular innervation,
or motor dysfunction in ALS. We recently showed that human mesenchymal stem
cells modified to release glial cell line-derived neurotrophic factor
(hMSC-GDNF) extend survival and protect NMJs and motor neurons in SOD1(G93A)
rats when delivered to limb muscles. In this study, we evaluate inflammatory and
glial responses near NMJs in the limb muscle collected from a rat model of
familial ALS (SOD1(G93A) transgenic rats) during disease progression and
following hMSC-GDNF transplantation. Muscle samples were collected from
pre-symptomatic, symptomatic, and end-stage animals. A significant increase in
the expression of microglial inflammatory markers (CD11b and CD68) occurred in
the skeletal muscle of symptomatic and end-stage SOD1(G93A) rats. Inflammation
was confirmed by ELISA for inflammatory cytokines interleukin-1 β (IL-1β) and
tumor necrosis factor-α (TNF-α) in muscle homogenates of SOD1(G93A) rats. Next,
we observed active glial responses in the muscle of SOD1(G93A) rats,
specifically near intramuscular axons and NMJs. Interestingly, strong expression
of activated glial markers, glial fibrillary acidic protein (GFAP) and nestin,
was observed in the areas adjacent to NMJs. Finally, we determined whether ex
vivo trophic factor delivery influences inflammation and terminal Schwann cell
(TSC) response during ALS. We found that intramuscular transplantation of
hMSC-GDNF tended to exhibit less inflammation and significantly maintained TSC
association with NMJs. Understanding cellular responses near NMJs is important
to identify suitable cellular and molecular targets for novel treatment of ALS
and other neuromuscular diseases. Muscle weakness is considered the pivotal sign of amyotrophic lateral sclerosis
(ALS). Knowledge about the skeletal muscle degeneration/regeneration process and
the myogenic potential is limited in ALS patients. Therefore, we investigate
these processes in a time course perspective by analysing skeletal muscle
biopsies from ALS patients collected before and after a 12-week period of normal
daily activities and compare these with healthy age-matched control tissue. We
do this by evaluating mRNA and protein (immunohistochemical) markers of
regeneration, neurodegeneration, myogenesis, cell cycle regulation, and
inflammation. Our results show morphological changes indicative of active
denervation and reinnervation and an increase in small atrophic fibres. We
demonstrate differences between ALS and controls in pathways controlling
skeletal muscle homeostasis, cytoskeletal and regenerative markers,
neurodegenerative factors, myogenic factors, cell cycle determits, and
inflammatory markers. Our results on Pax7 and MyoD protein expression suggest
that proliferation and differentiation of skeletal muscle stem cells are
affected in ALS patients, and the myogenic processes cannot overcome the
denervation-induced wasting. From early description by Charcot, the classification of the Amyotrophic Lateral
Sclerosis (ALS) is evolving from a subtype of Motor Neuron (MN) Disease to be
considered rather a multi-systemic, non-cell autonomous and complex
neurodegenerative disease. In the last decade, the huge amount of knowledge
acquired has shed new insights on the pathological mechanisms underlying ALS
from different perspectives. However, a whole vision on the multiple
dysfunctional pathways is needed with the inclusion of information often
excluded in other published revisions. We propose an integrative view of ALS
pathology, although centered on the synaptic failure as a converging and crucial
player to the etiology of the disease. Homeostasis of input and output synaptic
activity of MNs has been proved to be severely and early disrupted and to
definitively contribute to microcircuitry alterations at the spinal cord.
Several cells play roles in synaptic communication across the MNs network system
such as interneurons, astrocytes, microglia, Schwann and skeletal muscle cells.
Microglia are described as highly dynamic surveying cells of the nervous system
but also as determit contributors to the synaptic plasticity linked to
neuronal activity. Several signaling axis such as TNFα/TNFR1 and CX3CR1/CX3CL1
that characterize MN-microglia cross talk contribute to synaptic scaling and
maintece, have been found altered in ALS. The presence of dystrophic and
atypical microglia in late stages of ALS, with a decline in their dynamic
motility and phagocytic ability, together with less synaptic and neuronal
contacts disrupts the MN-microglia dialogue, decreases homeostatic regulation of
neuronal activity, perturbs "on/off" signals and accelerates disease progression
associated to impaired synaptic function and regeneration. Other hotspot in the
ALS affected network system is the unstable neuromuscular junction (NMJ) leading
to distal axonal degeneration. Reduced neuromuscular spontaneous synaptic
activity in ALS mice models was also suggested to account for the selective
vulnerability of MNs and decreased regenerative capability. Synaptic
destabilization may as well derive from increased release of molecules by muscle
cells (e.g. NogoA) and by terminal Schwann cells (e.g. semaphorin 3A)
conceivably causing nerve terminal retraction and denervation, as well as
inhibition of re-connection to muscle fibers. Indeed, we have overviewed the
alterations on the metabolic pathways and self-regenerative capacity presented
in skeletal muscle cells that contribute to muscle wasting in ALS. Finally, a
detailed footpath of pathologic changes on MNs and associated dysfunctional and
synaptic alterations is provided. The oriented motivation in future ALS studies
as outlined in the present article will help in fruitful novel achievements on
the mechanisms involved and in developing more target-driven therapies that will
bring new hope in halting or delaying disease progression in ALS patients. Amyotrophic lateral sclerosis (ALS) is a devastating neuromuscular disease
characterized by motor neuron loss and prominent skeletal muscle wasting.
Despite more than one hundred years of research efforts, the pathogenic
mechanisms underlying neuromuscular degeneration in ALS remain elusive. While
the death of motor neuron is a defining hallmark of ALS, accumulated evidences
suggested that in addition to being a victim of motor neuron axonal withdrawal,
the intrinsic skeletal muscle degeneration may also actively contribute to ALS
disease pathogenesis and progression. Examination of spinal cord and muscle
autopsy/biopsy samples of ALS patients revealed similar mitochondrial
abnormalities in morphology, quantity and disposition, which are accompanied by
defective mitochondrial respiratory chain complex and elevated oxidative stress.
Detailing the molecular/cellular mechanisms and the role of mitochondrial
dysfunction in ALS relies on ALS animal model studies. This review article
discusses the dysregulated mitochondrial Ca2+ and reactive oxygen species (ROS)
signaling revealed in live skeletal muscle derived from ALS mouse models, and a
potential role of the vicious cycle formed between the dysregulated
mitochondrial Ca2+ signaling and excessive ROS production in promoting muscle
wasting during ALS progression. Amyotrophic lateral sclerosis (ALS) is an adult onset disorder characterized by
progressive neuromuscular junction (NMJ) dismantling and degeneration of motor
neurons leading to atrophy and paralysis of voluntary muscles responsible for
motion and breathing. Except for a minority of patients harbouring genetic
mutations, the origin of most ALS cases remains elusive. Peripheral tissues, and
particularly skeletal muscle, have lately demonstrated an active contribution to
disease pathology attracting a growing interest for these tissues as therapeutic
targets in ALS. In this sense, molecular mechanisms essential for cell and
tissue homeostasis have been shown to be deregulated in the disease. These
include muscle metabolism and mitochondrial activity, RNA processing,
tissue-resident stem cell function responsible for muscle regeneration, and
proteostasis that regulates muscle mass in adulthood. This review aims to
compile scientific evidence that demonstrates the role of skeletal muscle in ALS
pathology and serves as reference for development of novel therapeutic
strategies targeting this tissue to delay disease onset and progression. LINKED
ARTICLES: This article is part of a themed issue on Neurochemistry in Japan. To
view the other articles in this section visit
http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.6/issuetoc. The prominent causes for motor neuron diseases like ALS are demyelination,
immune dysregulation, and neuroinflammation. Numerous research studies indicate
that the downregulation of IGF-1 and GLP-1 signaling pathways plays a
significant role in the progression of ALS pathogenesis and other neurological
disorders. In the current review, we discussed the dysregulation of IGF-1/GLP-1
signaling in neurodegenerative manifestations of ALS like a genetic anomaly,
oligodendrocyte degradation, demyelination, glial overactivation, immune
deregulation, and neuroexcitation. In addition, the current review reveals the
IGF-1 and GLP-1 activators based on the premise that the restoration of abnormal
IGF-1/GLP-1 signaling could result in neuroprotection and neurotrophic effects
for the clinical-pathological presentation of ALS and other brain diseases.
Thus, the potential benefits of IGF-1/GLP-1 signal upregulation in the
development of disease-modifying therapeutic strategies may prevent ALS and
associated neurocomplications. Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease
characterized by loss of both upper and lower motor neurons (MNs). The main
clinical features of ALS are motor function impairment, progressive muscle
weakness, muscle atrophy and, ultimately, paralysis. Intrinsic skeletal muscle
deterioration plays a crucial role in the disease and contributes to ALS
progression. Currently, there are no effective treatments for ALS, highlighting
the need to obtain a deeper understanding of the molecular events underlying
degeneration of both MNs and muscle tissue, with the aim of developing
successful therapies. Muscle tissue is enriched in a group of microRNAs called
myomiRs, which are effective regulators of muscle homeostasis, plasticity and
myogenesis in both physiological and pathological conditions. After providing an
overview of ALS pathophysiology, with a focus on the role of skeletal muscle, we
review the current literature on myomiR network dysregulation as a contributing
factor to myogenic perturbations and muscle atrophy in ALS. We argue that, in
view of their critical regulatory function at the interface between MNs and
skeletal muscle fiber, myomiRs are worthy of further investigation as potential
molecular targets of therapeutic strategies to improve ALS symptoms and
counteract disease progression. Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that
leads to progressive degeneration of motor neurons (MNs) and severe muscle
atrophy without effective treatment. Most research on ALS has been focused on
the study of MNs and supporting cells of the central nervous system. Strikingly,
the recent observations of pathological changes in muscle occurring before
disease onset and independent from MN degeneration have bolstered the interest
for the study of muscle tissue as a potential target for delivery of therapies
for ALS. Skeletal muscle has just been described as a tissue with an important
secretory function that is toxic to MNs in the context of ALS. Moreover, a
fine-tuning balance between biosynthetic and atrophic pathways is necessary to
induce myogenesis for muscle tissue repair. Compromising this response due to
primary metabolic abnormalities in the muscle could trigger defective muscle
regeneration and neuromuscular junction restoration, with deleterious
consequences for MNs and thereby hastening the development of ALS. However, it
remains puzzling how backward signaling from the muscle could impinge on MN
death. This review provides a comprehensive analysis on the current
state-of-the-art of the role of the skeletal muscle in ALS, highlighting its
contribution to the neurodegeneration in ALS through backward-signaling
processes as a newly uncovered mechanism for a peripheral etiopathogenesis of
the disease. Amyotrophic lateral sclerosis (ALS) is a terminalneurodegenerative disease.
Clinical and molecular observations suggest that ALS pathology originates at a
single site and spreads in an organized and prion-like manner, possibly driven
by extracellular vesicles. Extracellular vesicles (EVs) transfer cargo molecules
associated with ALS pathogenesis, such as misfolded and aggregated proteins and
dysregulated microRNAs (miRNAs). However, it is poorly understood whether
altered levels of circulating extracellular vesicles or their cargo components
reflect pathological signatures of the disease. In this study, we used
immuno-affinity-based microfluidic technology, electron microscopy, and
NanoString miRNA profiling to isolate and characterize extracellular vesicles
and their miRNA cargo from frontal cortex, spinal cord, and serum of sporadic
ALS (n = 15) and healthy control (n = 16) participants. We found larger
extracellular vesicles in ALS spinal cord versus controls and smaller sized
vesicles in ALS serum. However, there were no changes in the number of
extracellular vesicles between cases and controls across any tissues.
Characterization of extracellular vesicle-derived miRNA cargo in ALS compared to
controls identified significantly altered miRNA levels in all tissues; miRNAs
were reduced in ALS frontal cortex and spinal cord and increased in serum. Two
miRNAs were dysregulated in all three tissues: miR-342-3p was increased in ALS,
and miR-1254 was reduced in ALS. Additional miRNAs overlapping across two
tissues included miR-587, miR-298, miR-4443, and miR-450a-2-3p. Predicted
targets and pathways associated with the dysregulated miRNAs across the ALS
tissues were associated with common biological pathways altered in
neurodegeneration, including axon guidance and long-term potentiation. A
predicted target of one identified miRNA (N-deacetylase and N-sulfotransferase
4; NDST4) was likewise dysregulated in an in vitro model of ALS, verifying
potential biological relevance. Together, these findings demonstrate that
circulating extracellular vesicle miRNA cargo mirror those of the central
nervous system disease state in ALS, and thereby offer insight into possible
pathogenic factors and diagnostic opportunities. |
For what known mutations is KRAS gene considered to be oncogenic? | G12C, G12V, G12D and G12A are all observed mutations of the KRAS oncogene. | BACKGROUND: In certain non-small cell lung cancer (NSCLC) populations, codon 12
mutations of the KRAS oncogene comprising mostly G-T transversions have
diagnostic and prognostic value. However, it is not known if these findings are
applicable to all populations of lung cancer patients.
AIMS: To examine for KRAS codon 12 mutations in Australian NSCLC patients.
METHODS: Tumour samples and corresponding normal lung tissue from 108 Australian
patients with NSCLC undergoing curative resection were studied for mutations of
KRAS codon 12 using a sensitive PCR assay. Mutations were confirmed by DNA
sequencing and correlated with histological subtype, tumour stage, the presence
of nodal metastases and survival.
RESULTS: Eleven KRAS codon 12 mutations were detected in 108 NSCLCs, with most
(8/11) occurring in the adenocarcinoma subtype (17% prevalence), but were not
associated with adverse outcome or clinico-pathological features. G-T
transversions were surprisingly infrequent (37% of adenocarcinoma mutations).
CONCLUSIONS: These data add to the evidence suggesting geographical differences
in the spectrum and significance of KRAS codon 12 mutational genotypes in NSCLC.
While these may be due to genetic variation and/or differences in carcinogen
exposure, there is a need for larger population based studies before this
potentially important biomarker can be recommended universally for optimising
lung cancer management. We previously reported the occurrence of novel dinucleotide mutations of the
K-RAS gene (KRAS2) in 2% of pancreatic tumors sampled, but it remained unknown
whether these were functional mutations that convert the proto-oncogene to an
oncogene, or unselected mutations that might inactivate protein function. In the
current study, the functionality of these rare mutations was quantitated via a
mitogen-activated protein kinase (MAPK) pathway-specific transactivational
reporter system. Pathway activation by dinucleotide mutant proteins was
comparable to that of the common G12V mutant K-Ras protein. Current
allele-specific technologies often employed to detect K-RAS mutations in
clinical tumor samples produce false results when dinucleotide mutations are
present. Therefore, it is advisable to consider dinucleotide KRAS2 mutants in
the strategic design of mutational screens used to assay clinical tumor samples.
Hum Mutat 18:357, 2001. BACKGROUND: Mutations of KRAS are known to occur in periampullary and ampullary
adenomas and carcinomas. However, nothing is known about NRAS, HRAS, BRAF, and
PIK3CA mutations in these tumors. While oncogenic BRAF contributes to the
tumorigenesis of both pancreatic ductal adenocarcinoma and intraductal papillary
mucinous neoplasms/carcinomas (IPMN/IPMC), PIK3CA mutations were only detected
in IPMN/IPMC. This study aimed to elucidate possible roles of BRAF and PIK3CA in
the development of ampullary and periampullary adenomas and carcinomas.
METHODS: Mutations of BRAF, NRAS, HRAS, KRAS, and PIK3CA were evaluated in seven
adenomas, seven adenomas with carcinoma in situ, and 21 adenocarcinomas of the
periampullary duodenal region and the ampulla of Vater. Exons 1 of KRAS; 2 and 3
of NRAS and HRAS; 5, 11, and 15 of BRAF; and 9 and 20 of PIK3CA were examined by
direct genomic sequencing.
RESULTS: In total, we identified ten (28.6%) KRAS mutations in exon 1 (nine in
codon 12 and one in codon 13), two missense mutations of BRAF (6%), one within
exon 11 (G469A), and one V600E hot spot mutation in exon 15 of BRAF. BRAF
mutations were present in two of five periampullary tumors. All mutations appear
to be somatic since the same alterations were not detected in the corresponding
normal tissues.
CONCLUSION: Our data provide evidence that oncogenic properties of KRAS and BRAF
but not NRAS, HRAS, and PIK3CA contribute to the tumorigenesis of periampullary
and ampullary tumors; BRAF mutations occur more frequently in periampullary than
ampullary neoplasms. BACKGROUND: Mutational analysis of the KRAS gene has recently been established
as a complementary in vitro diagnostic tool for the identification of patients
with colorectal cancer who will not benefit from anti-epidermal growth factor
receptor (EGFR) therapies. Assessment of the mutation status of KRAS might also
be of potential relevance in other EGFR-overexpressing tumors, such as those
occurring in breast cancer. Although KRAS is mutated in only a minor fraction of
breast tumors (5%), about 60% of the basal-like subtype express EGFR and,
therefore could be targeted by EGFR inhibitors. We aimed to study the mutation
frequency of KRAS in that subtype of breast tumors to provide a molecular basis
for the evaluation of anti-EGFR therapies.
METHODS: Total, genomic DNA was obtained from a group of 35 formalin-fixed
paraffin-embedded, triple-negative breast tumor samples. Among these, 77.1%
(27/35) were defined as basal-like by immunostaining specific for the
established surrogate markers cytokeratin (CK) 5/6 and/or EGFR. KRAS mutational
status was determined in the purified DNA samples by Real Time (RT)-PCR using
primers specific for the detection of wild-type KRAS or the following seven
oncogenic somatic mutations: Gly12Ala, Gly12Asp, Gly12Arg, Gly12Cys, Gly12Ser,
Gly12Val and Gly13Asp.
RESULTS: We found no evidence of KRAS oncogenic mutations in all analyzed
tumors.
CONCLUSIONS: This study indicates that KRAS mutations are very infrequent in
triple-negative breast tumors and that EGFR inhibitors may be of potential
benefit in the treatment of basal-like breast tumors, which overexpress EGFR in
about 60% of all cases. Lung cancer, like other cancers, is considered to develop through the
accumulation of genetic alterations. Mutation of the KRAS gene is one of the
most important events in carcinogenesis of the lung. The KRAS gene, belonging to
the RAS gene family, encodes a membrane-bound 21-kd guanosine triphosphate
(GTP)-binding protein. Single point mutations in this protein result in
continuous activation to transmit excessive signals, promoting a variety of
biological events. In lung cancers, the mutations concentrate at codon 12 and
mostly affect adenocarcinomas (ADCs). They also affect atypical adenomatous
hyperplasia, the precursor of ADCs. Therefore, mutation of the KRAS gene is
suggested to confer a growth advantage to airway epithelial cells enabling them
to expand clonally early in the development of ADCs. The mutation is also a
reliable marker of an unfavorable response to certain molecular-targeting
therapies. Furthermore, patients with ADCs affected by mutations have been
reported to exhibit a significantly higher risk of postoperative disease
recurrence. Thus, the significance of KRAS gene mutations has been investigated
extensively. However, not all the details emerged. In this review, particulars
that have been established are introduced, and important issues remaining to be
resolved are discussed, with special reference to carcinogenesis of the lung. Pancreatic cancer is almost invariably associated with mutations in the KRAS
gene, most commonly KRASG12D, that result in a domit-active form of the KRAS
GTPase. However, how KRAS mutations promote pancreatic carcinogenesis is not
fully understood, and whether oncogenic KRAS is required for the maintece of
pancreatic cancer has not been established. To address these questions, we
generated two mouse models of pancreatic tumorigenesis: mice transgenic for
inducible KrasG12D, which allows for inducible, pancreas-specific, and
reversible expression of the oncogenic KrasG12D, with or without inactivation of
one allele of the tumor suppressor gene p53. Here, we report that, early in
tumorigenesis, induction of oncogenic KrasG12D reversibly altered normal
epithelial differentiation following tissue damage, leading to precancerous
lesions. Inactivation of KrasG12D in established precursor lesions and during
progression to cancer led to regression of the lesions, indicating that KrasG12D
was required for tumor cell survival. Strikingly, during all stages of
carcinogenesis, KrasG12D upregulated Hedgehog signaling, inflammatory pathways,
and several pathways known to mediate paracrine interactions between epithelial
cells and their surrounding microenvironment, thus promoting formation and
maintece of the fibroinflammatory stroma that plays a pivotal role in
pancreatic cancer. Our data establish that epithelial KrasG12D influences
multiple cell types to drive pancreatic tumorigenesis and is essential for tumor
maintece. They also strongly support the notion that inhibiting KrasG12D, or
its downstream effectors, could provide a new approach for the treatment of
pancreatic cancer. Activation of KRAS oncogene has been implicated in colorectal carcinogenesis.
KRAS mutations can be detected in more than 30% of all patients with colorectal
cancer (CRC). Most recently, regimens that include anti-epidermal growth factor
receptor (EGFR) targeted antibodies, cetuximab and panitumumab, for metastatic
CRC have been developed. Several recent studies have shown that patients with
KRAS mutations in codons 12 and 13 in metastatic CRC do not benefit from
anti-EGFR therapy. With the aim to determine KRAS status as predictive
biomarker, 7 known mutations ofKRAS gene in codons 12 or 13 on 44 CRC samples
were tested. After DNA extraction from paraffin-embedded tumor tissue blocks,
KRAS mutations were analysed using quantitative real-time PCR with
internationally certified method, for the first time in Croatia. Mutations were
detected in 12 tumor samples: five patients with Gly12Val (GGT>GTT), three with
Gly12Asp (GGT>GAT), two patients with Gly13Asp (GGC>GAC), one patient with
Gly12Ser (GGT>AGT) and one with Gly12Cys (GGT>TGT) mutation in tumor. Our data
about KRAS mutational status in the sample of Croatian population diagnosed with
CRC have shown that incidence of KRAS mutation is 27%, which is consistent with
results already reported worldwide. The final result must be a proper selection
of the correct therapy with EGFR inhibitors for the patients with CRC which is
critical for improving clinical outcomes, unnecessary toxicities, side effects
and ficial cost. Somatic activation of the KRAS proto-oncogene is evident in almost all
pancreatic cancers, and appears to represent an initiating event. These
mutations occur primarily at codon 12 and less frequently at codons 13 and 61.
Although some studies have suggested that different KRAS mutations may have
variable oncogenic properties, to date there has been no comprehensive
functional comparison of multiple KRAS mutations in an in vivo vertebrate
tumorigenesis system. We generated a Gal4/UAS-based zebrafish model of
pancreatic tumorigenesis in which the pancreatic expression of UAS-regulated
oncogenes is driven by a ptf1a:Gal4-VP16 driver line. This system allowed us to
rapidly compare the ability of 12 different KRAS mutations (G12A, G12C, G12D,
G12F, G12R, G12S, G12V, G13C, G13D, Q61L, Q61R and A146T) to drive pancreatic
tumorigenesis in vivo. Among fish injected with one of five KRAS mutations
reported in other tumor types but not in human pancreatic cancer, 2/79 (2.5%)
developed pancreatic tumors, with both tumors arising in fish injected with
A146T. In contrast, among fish injected with one of seven KRAS mutations known
to occur in human pancreatic cancer, 22/106 (20.8%) developed pancreatic cancer.
All eight tumorigenic KRAS mutations were associated with downstream MAPK/ERK
pathway activation in preneoplastic pancreatic epithelium, whereas
nontumorigenic mutations were not. These results suggest that the spectrum of
KRAS mutations observed in human pancreatic cancer reflects selection based on
variable tumorigenic capacities, including the ability to activate MAPK/ERK
signaling. Although all KRas (protein that in humans is encoded by the KRas gene) point
mutants are considered to have a similar prognostic capacity, their
transformation and tumorigenic capacities vary widely. We compared the
metastatic efficiency of KRas G12V (Kirsten rat sarcoma viral oncogene homolog
with valine mutation at codon 12) and KRas G13D (Kirsten rat sarcoma viral
oncogene homolog with aspartic mutation at codon 13) oncogenes in an orthotopic
colorectal cancer (CRC) model. Following subcutaneous preconditioning,
recombit clones of the SW48 CRC cell line [Kras wild-type (Kras WT)]
expressing the KRas G12V or KRas G13D allele were microinjected in the mouse
cecum. The percentage of animals developing lymph node metastasis was higher in
KRas G12V than in KRas G13D mice. Microscopic, macroscopic, and visible
lymphatic foci were 1.5- to 3.0-fold larger in KRas G12V than in KRas G13D mice
(P < 0.05). In the lung, only microfoci were developed in both groups. KRas G12V
primary tumors had lower apoptosis (7.0 ± 1.2 vs. 7.4 ± 1.0 per field, P =
0.02), higher tumor budding at the invasion front (1.2 ± 0.2 vs. 0.6 ± 0.1, P =
0.04), and a higher percentage of C-X-C chemokine receptor type 4
(CXCR4)-overexpressing intravasated tumor emboli (49.8 ± 9.4% vs. 12.8 ± 4.4%, P
< 0.001) than KRas G13D tumors. KRas G12V primary tumors showed Akt activation,
and β5 integrin, vascular endothelial growth factor A (VEGFA), and Serpine-1
overexpression, whereas KRas G13D tumors showed integrin β1 and angiopoietin 2
(Angpt2) overexpression. The increased cell survival, invasion, intravasation,
and specific molecular regulation observed in KRas G12V tumors is consistent
with the higher aggressiveness observed in patients with CRC expressing this
oncogene. BACKGROUND: Somatic mutations have been related to the highest incidence of
metastatic disease and different treatment responses. The molecular cause of
prostate cancer (PC) is still unclear; however, its progression involves
alterations in oncogenes and tumor suppressor genes as well as somatic mutations
such as the ones in PIK3CA gene. A high percentage of PC is considered sporadic,
which means that the damage to the genes occurs by chance after birth (mainly
somatic mutations will drive the cancer event). However, little is known about
somatic mutations in PC development.
MATERIALS AND METHODS: We evaluated prostate biopsies in the main somatic
mutations genes (PIK3CA, TP53, EGFR, KIT, KRAS, PTEN, and BRAF) among
individuals with PSA values>4ng/ml (n = 125), including affected and unaffected
PC subjects.
RESULTS: Mutations in KIT gene are related to aggressive PC: TNM stages II to
III, Gleason score ≥ 7 and D'Amico risk (P = 0.037, 0.040, and 0.017). However,
there are no statistical significant results when more than 3 somatic mutations
are presented in the same individual. In relation to environmental factors
(smoking, diet, alcohol intake, or workplace exposure) there are no significant
differences in the effect of environmental exposure and the somatic mutation
presence. The most prevalent mutations among patients with PC are c.1621A>C
(rs3822214) in KIT, c.38G>C (rs112445441) in KRAS and c.733G>A (rs28934575) in
TP53 genes. KRAS, KIT, and TP53 genes are the most prevalent ones in patients
with PC.
CONCLUSIONS: Somatic alterations predisposing to chromosomal rearrangements in
PC remain largely undefined. We show that KIT, KRAS, and TP53 genes have a
higher presence among patients with PC and that mutations in KIT gene are
related to an aggressive PC. However, we did not find any environmental effect
in somatic mutations among PC individuals. A mutated KRAS protein is frequently observed in human cancers. Traditionally,
the oncogenic properties of KRAS missense mutants at position 12 (G12X) have
been considered as equal. Here, by assessing the probabilities of occurrence of
all KRAS G12X mutations and KRAS dynamics we show that this assumption does not
hold true. Instead, our findings revealed an outstanding mutational bias. We
conducted a thorough mutational analysis of KRAS G12X mutations and assessed to
what extent the observed mutation frequencies follow a random distribution.
Unique tissue-specific frequencies are displayed with specific mutations,
especially with G12R, which cannot be explained by random probabilities. To
clarify the underlying causes for the nonrandom probabilities, we conducted
extensive atomistic molecular dynamics simulations (170 μs) to study the
differences of G12X mutations on a molecular level. The simulations revealed an
allosteric hydrophobic signaling network in KRAS, and that protein dynamics is
altered among the G12X mutants and as such differs from the wild-type and is
mutation-specific. The shift in long-timescale conformational dynamics was
confirmed with Markov state modeling. A G12X mutation was found to modify KRAS
dynamics in an allosteric way, which is especially manifested in the switch
regions that are responsible for the effector protein binding. The findings
provide a basis to understand better the oncogenic properties of KRAS G12X
mutants and the consequences of the observed nonrandom frequencies of specific
G12X mutations. The 3 human RAS genes, KRAS, NRAS, and HRAS, encode 4 different RAS proteins
which belong to the protein family of small GTPases that function as binary
molecular switches involved in cell signaling. Activating mutations in RAS are
among the most common oncogenic drivers in human cancers, with KRAS being the
most frequently mutated oncogene. Although KRAS is an excellent drug discovery
target for many cancers, and despite decades of research, no therapeutic agent
directly targeting RAS has been clinically approved. Using structure-based drug
design, we have discovered BI-2852 (1), a KRAS inhibitor that binds with
omolar affinity to a pocket, thus far perceived to be "undruggable," between
switch I and II on RAS; 1 is mechanistically distinct from covalent KRASG12C
inhibitors because it binds to a different pocket present in both the active and
inactive forms of KRAS. In doing so, it blocks all GEF, GAP, and effector
interactions with KRAS, leading to inhibition of downstream signaling and an
antiproliferative effect in the low micromolar range in KRAS mutant cells. These
findings clearly demonstrate that this so-called switch I/II pocket is indeed
druggable and provide the scientific community with a chemical probe that
simultaneously targets the active and inactive forms of KRAS. The RAS genes, which include H, N, and KRAS, comprise the most frequently
mutated family of oncogenes in cancer. Mutations in KRAS - such as the G12C
mutation - are found in most pancreatic, half of colorectal and a third of lung
cancer cases and is thus responsible for a substantial proportion of cancer
deaths. Consequently, KRAS has been the subject of exhaustive drug-targeting
efforts over the past 3-4 decades. These efforts have included targeting the
KRAS protein itself but also its posttranslational modifications, membrane
localization, protein-protein interactions and downstream signalling pathways.
Most of these strategies have failed and no KRAS-specific drugs have yet been
approved. However, for one specific mutation, KRASG12C , there is light on the
horizon. MRTX849 was recently identified as a potent, selective and covalent
KRASG12C inhibitor that possesses favourable drug-like properties. MRTX849
selectively modifies the mutant cysteine residue in GDP-bound KRASG12C and
inhibits GTP-loading and downstream KRAS-dependent signalling. The drug inhibits
the in vivo growth of multiple KRASG12C -mutant cell line xenografts, causes
tumour regression in patient-derived xenograft models and shows striking
responses in combination with other agents. It has also produced objective
responses in patients with mutant-specific lung and colorectal cancer. In this
review, we discuss the history of RAS drug-targeting efforts, the discovery of
MRTX849, and how this drug provides an exciting and long-awaited opportunity to
selectively target mutant KRAS in patients. Rationale: KRAS is one of the most frequently mutated oncogenes in cancers. The
protein's picomolar affinity for GTP/GDP and smooth protein structure resulting
in the absence of known allosteric regulatory sites makes its genomic-level
activating mutations a difficult but attractive target. Methods: Two CRISPR
systems, genome-editing CRISPR/SpCas9 and transcription-regulating dCas9-KRAB,
were developed to deplete the KRAS G12S mutant allele or repress its
transcription, respectively, with the goal of treating KRAS-driven cancers.
Results: SpCas9 and dCas9-KRAB systems with a sgRNA targeting the mutant allele
blocked the expression of the mutant KRAS gene, leading to an inhibition of
cancer cell proliferation. Local adenoviral injections using SpCas9 and
dCas9-KRAB systems suppressed tumor growth in vivo. The gene-depletion system
(SpCas9) performed more effectively than the transcription-suppressing system
(dCas9-KRAB) on tumor inhibition. Application of both Cas9 systems to wild-type
KRAS tumors did not affect cell proliferation. Furthermore, through
bioinformatic analysis of 31555 SNP mutations of the top 20 cancer driver genes,
the data showed that our mutant-specific editing strategy could be extended to a
reference list of oncogenic mutations with high editing potentials. This
pipeline could be applied to analyze the distribution of PAM sequences and
survey the best alternative targets for gene editing. Conclusion: We
successfully developed both gene-depletion and transcription-suppressing systems
to specifically target an oncogenic KRAS mutant allele that led to significant
tumor regression. These findings show the potential of CRISPR-based strategies
for the treatment of tumors with driver gene mutations. OBJECTIVES: The efficacy of anti- programmed cell death 1 (PD-1)/PD-1 ligand
(PD-L1) immune checkpoint inhibitors remains controversial in patients with KRAS
mutation. In addition, whether and how KRAS gene and its mutant subtypes might
influence immunity has not been clarified yet. Here we examine some important
biomarkers for the efficacy of immunotherapy in specific KRAS subtypes.
MATERIALS AND METHODS: We conducted a bioinformatics analysis on somatic
mutations data, transcriptome sequencing data and proteomic data from The Cancer
Genome Atlas (TCGA) database. CIBERSORT was used to provide an estimation of the
abundances of immune cells using gene expression data.
RESULTS: From a cohort of 567 patients with lung adenocarcinoma (LUAD) based on
TCGA, the overall mutation rate of KRAS was 26.29 %, including KRAS/TP53
co-mutation rate of 9.7 %. We observed increased Tumor mutation burden (TMB) in
KRAS mutant group compared with wild type, while no difference in PD-L1
expression and immune cell infiltration. More importantly, TP53 and KRAS/TP53
co-mutation group not only significantly increased tumor mutation burden, but
also had higher PD-L1 protein level and immune cell infiltration. We further
focused on influence of KRAS mutant subtype on immune biomarker. The most
prevalent mutant subtype of KRAS in lung adenocarcinoma was G12C(9.88 %,56/567),
followed by G12 V(5.82 %,33/567), G12D(3.00 %,17/567), G12A(3.00 %,17/567),
respectively. Among them, G12D mutation appeared to be a special mutant subtype
with an obviously lower TMB. This low mutation load was more significant when
co-mutation with TP53. Besides, our results also revealed significantly
decreased expressions of PD-L1 protein level and immune cell infiltration
(activated CD4 memory T cell, helper T cell, M1 macrophage and NK cell) in KRAS
G12D/TP53 mutant group.
CONCLUSION: KRAS G12D/TP53 co-mutation drives immune suppression and might be a
negative predictive biomarker for anti-PD-1/PD-L1 immune checkpoint inhibitors
in patients with lung adenocarcinoma. Although clinical data suggest remarkable promise for targeting programmed cell
death protein-1 (PD-1) and ligand (PD-L1) signaling in non-small-cell lung
cancer (NSCLC), it is still largely undetermined which subtype of patients will
be responsive to checkpoint blockade. In the present study, we explored whether
PD-L1 was regulated by mutant Kirsten rat sarcoma viral oncogene homolog (KRAS),
which is frequently mutated in NSCLC and results in poor prognosis and low
survival rates. We verified that PD-L1 levels were dramatically increased in
KRAS mutant cell lines, particularly in NCI-H441 cells with KRAS G12V mutation.
Overexpression of KRAS G12V remarkably elevated PD-L1 messenger RNA and protein
levels, while suppression of KRAS G12V led to decreased PD-L1 levels in NCI-H441
cells. Consistently, higher levels of PD-L1 were observed in KRAS-mutated
tissues as well as tumor tissues-derived CD4+ and CD8+ T cells using a tumor
xenograft in B-NDG mice. Mechanically, both in vitro and in vivo assays found
that KRAS G12V upregulated PD-L1 via regulating the progression of
epithelial-to-mesenchymal transition (EMT). Moreover, pembrolizumab activated
the antitumor activity and decreased tumor growth with KRAS G12V mutated NSCLC.
This study demonstrates that KRAS G12V mutation could induce PD-L1 expression
and promote immune escape via transforming growth factor-β/EMT signaling pathway
in KRAS-mutant NSCLC, providing a potential therapeutic approach for NSCLC
harboring KRAS mutations. Mutation in the gene that encodes Kirsten rat sarcoma viral oncogene homolog
(KRAS) is the most common oncogenic driver in advanced non-small cell lung
cancer, occurring in approximately 30% of lung adenocarcinomas. Over 80% of
oncogenic KRAS mutations occur at codon 12, where the glycine residue is
substituted by different amino acids, leading to genomic heterogeneity of
KRas-mutant tumors. The KRAS glycine-to-cysteine mutation (G12C) composes
approximately 44% of KRAS mutations in non-small cell lung cancer, with mutant
KRasG12C present in approximately 13% of all patients with lung adenocarcinoma.
Mutant KRas has been an oncogenic target for decades, but no viable therapeutic
agents were developed until recently. However, advances in KRas molecular
modeling have led to the development and clinical testing of agents that
directly inhibit mutant KRasG12C. These agents include sotorasib (AMG-510),
adagrasib (MRTX-849), and JNJ-74699157. In addition to testing for known
actionable oncogenic driver alterations in EGFR, ALK, ROS1, BRAF, MET exon 14
skipping, RET, and NTRK and for the expression of programmed cell-death protein
ligand 1, pathologists, medical oncologists, and community practitioners will
need to incorporate routine testing for emerging biomarkers such as MET
amplification, ERBB2 (alias HER2), and KRAS mutations, particularly KRAS G12C,
considering the promising development of direct inhibitors of KRasG12C protein. Activating mutations in the KRAS gene (Kirsten rat sarcoma 2 viral oncogene
homolog gene) are commonly seen across the various solid organ and
hematolymphoid neoplasms. With the likelihood of the mutation specific KRAS
inhibitor entering clinical practice, the present studies profiled the landscape
of these mutations in the Indian population to add to databases and posit the
clinical utility of its emerging inhibitors. This study included 489 formalin
fixed paraffin-embedded (FFPE) tissue samples from consecutive patients during a
5-year period (2015-2019). The clinical records were obtained from the medical
record archives of the institution. Library preparation was done using the
Oncomine Assay™. Sequencing was performed using the Ion PGM Hi-Q Sequencing Kit
on the Ion Torrent Personal Genome Machine (Ion PGM) as well as on Ion Torrent
S5 sequencer using the S5 sequencing kit. Ion Torrent Suite™ Browser version
5.10 and Ion Reporter™ version 5.10 were used for data analysis. A total of 50
cases with KRAS mutations were observed occurring most commonly in the codons 12
and 13. The G12D mutation was the most commonly encountered subtype in our
cohort (21/50), whereas the G12C mutation was observed in 5 cases, and
interestingly, this mutation was only seen in patients with non-small cell lung
carcinoma (NSCLC). In the largest cohort from Indian subcontinent reporting
spectrum of KRAS mutations in human cancers, an incidence of 11% was observed
across all cancer types. Therapies targeting the G12C mutations can benefit up
to 20% KRAS-mutated NSCLC. Building databases of spectrum of KRAS mutations in
different populations across diverse cancer types is the anticipatory step to
this end. Oncogenic mutations in the KRAS gene are well-established drivers of cancer.
While the recently developed KRASG12C inhibitors offer a targeted KRAS therapy
and have shown success in the clinic, KRASG12C represents only 11% of all KRAS
mutations. Current therapeutic approaches for all other KRAS mutations are both
indirect and nonmutant-selective, largely focusing on inhibition of downstream
KRAS effectors such as MAP kinases. Inhibition of KRAS downstream signaling
results in a system-wide down-modulation of the respective targets, raising
concerns about systemic cell toxicity. Here, we describe a custom short
interfering RNA oligonucleotide (EFTX-D1) designed to preferentially bind mRNA
of the most commonly occurring KRAS missense mutations in codons 12 and 13. We
determined that EFTX-D1 preferentially reduced the mutant KRAS sequence versus
wild-type at the levels of both transcription and translation and reversed
oncogenic KRAS-induced morphologic and growth transformation. Furthermore,
EFTX-D1 significantly impaired the proliferation of several KRAS mutant cancer
cell lines in 2-D as well as 3-D assays. Taken together, our data indicate a
novel use of RNA interference to target oncogenic KRAS-driven cancers
specifically. Colorectal cancer (CRC) is one of the most important causes of morbidity and
mortality in the developed world and is gradually more frequent in the
developing world including Saudi Arabia. According to the Saudi Cancer Registry
report 2015, CRC is the most common cancer in men (14.9%) and the second most
prevalent cancer. Oncogenic mutations in the KRAS gene play a central role in
tumorigenesis and are mutated in 30-40% of all CRC patients. To explore the
prevalence of KRAS gene mutations in the Saudi population, we collected 80 CRC
tumor tissues and sequenced the KRAS gene using automated sequencing
technologies. The chromatograms presented mutations in 26 patients (32.5%) in
four different codons, that is, 12, 13, 17, and 31. Most of the mutations were
identified in codon 12 in 16 patients (61.5% of all mutations). We identified a
novel mutation c.51 G>A in codon 17, where serine was substituted by arginine
(S17R) in four patients. We also identified a very rare mutation, c.91 G>A, in
which glutamic acid was replaced by lysine (E31K) in three patients. In
conclusion, our findings further the knowledge about KRAS mutations in different
ethnic groups is indispensable to fully understand their role in the development
and progression of CRC. INTRODUCTION: KRAS was one of the earliest human oncogenes to be described and
is one of the most commonly mutated genes in different human cancers, including
colorectal cancer. Despite KRAS mutants being known driver mutations, KRAS has
proved difficult to target therapeutically, necessitating a comprehensive
understanding of the molecular mechanisms underlying KRAS-driven cellular
transformation.
OBJECTIVES: To investigate the metabolic signatures associated with single copy
mutant KRAS in isogenic human colorectal cancer cells and to determine what
metabolic pathways are affected.
METHODS: Using NMR-based metabonomics, we compared wildtype (WT)-KRAS and mutant
KRAS effects on cancer cell metabolism using metabolic profiling of the parental
KRAS G13D/+ HCT116 cell line and its isogenic, derivative cell lines KRAS +/-
and KRAS G13D/-.
RESULTS: Mutation in the KRAS oncogene leads to a general metabolic remodelling
to sustain growth and counter stress, including alterations in the metabolism of
amino acids and enhanced glutathione biosynthesis. Additionally, we show that
KRASG13D/+ and KRASG13D/- cells have a distinct metabolic profile characterized
by dysregulation of TCA cycle, up-regulation of glycolysis and glutathione
metabolism pathway as well as increased glutamine uptake and acetate
utilization.
CONCLUSIONS: Our study showed the effect of a single point mutation in one KRAS
allele and KRAS allele loss in an isogenic genetic background, hence avoiding
confounding genetic factors. Metabolic differences among different KRAS
mutations might play a role in their different responses to anticancer
treatments and hence could be exploited as novel metabolic vulnerabilities to
develop more effective therapies against oncogenic KRAS. |
Which proteins does the p85α interact with? | p85α interacts with itself, with p110α and with p110d | The p85alpha subunit of phosphatidylinositol 3-kinase (PI-3k) forms a complex
with a protein network associated with oncogenic fusion tyrosine kinases (FTKs)
such as BCR/ABL, TEL/ABL, TEL/JAK2, TEL/PDGFbetaR, and NPM/ALK, resulting in
constitutive activation of the p110 catalytic subunit of PI-3k. Introduction of
point mutations in the N-terminal and C-terminal SH2 domain and SH3 domain of
p85alpha, which disrupt their ability to bind phosphotyrosine and proline-rich
motifs, respectively, abrogated their interaction with the BCR/ABL protein
network. The p85alpha mutant protein (p85mut) bearing these mutations was unable
to interact with BCR/ABL and other FTKs, while its binding to the p110alpha
catalytic subunit of PI-3k was intact. In addition, binding of Shc, c-Cbl, and
Gab2, but not Crk-L, to p85mut was abrogated. p85mut diminished
BCR/ABL-dependent activation of PI-3k and Akt kinase, the downstream effector of
PI-3k. This effect was associated with the inhibition of BCR/ABL-dependent
growth of the hematopoietic cell line and murine bone marrow cells.
Interestingly, the addition of interleukin-3 (IL-3) rescued BCR/ABL-transformed
cells from the inhibitory effect of p85mut. SCID mice injected with
BCR/ABL-positive hematopoietic cells expressing p85mut survived longer than the
animals inoculated with BCR/ABL-transformed counterparts. In conclusion, we have
identified the domains of p85alpha responsible for the interaction with the FTK
protein network and transduction of leukemogenic signaling. Despite the fact that X-box binding protein-1 (XBP-1) is one of the main
regulators of the unfolded protein response (UPR), the modulators of XBP-1 are
poorly understood. Here, we show that the regulatory subunits of phosphotidyl
inositol 3-kinase (PI3K), p85alpha (encoded by Pik3r1) and p85beta (encoded by
Pik3r2) form heterodimers that are disrupted by insulin treatment. This
disruption of heterodimerization allows the resulting monomers of p85 to
interact with, and increase the nuclear translocation of, the spliced form of
XBP-1 (XBP-1s). The interaction between p85 and XBP-1s is lost in ob/ob mice,
resulting in a severe defect in XBP-1s translocation to the nucleus and thus in
the resolution of endoplasmic reticulum (ER) stress. These defects are
ameliorated when p85alpha and p85beta are overexpressed in the liver of ob/ob
mice. Our results define a previously unknown insulin receptor signaling pathway
and provide new mechanistic insight into the development of ER stress during
obesity. Inducible acetylation of p53 at lysine residues has a great impact on regulating
the transactivation of this protein, which is associated with cell growth arrest
and/or apoptosis under various stress conditions. However, the factor(s) for
regulating p53 acetylation remains largely unknown. In the current study, we
have shown that p85α, the regulatory subunit of phosphatidylinositol-3-kinase,
has a critical role in mediating p53 acetylation and promoter-specific
transactivation in the ultraviolet B (UVB) response. Depletion of p85α in mouse
embryonic fibroblasts significantly impairs UVB-induced apoptosis, as well as
p53 transactivation and acetylation at Lys370 (Lys373 of human p53); however,
the accumulation, nuclear translocation and phosphorylation of p53 are not
affected. Interestingly, p85α binds to p300, promotes the p300-p53 interaction
and the subsequent recruitment of the p53/p300 complex to the promoter region of
the specific p53 target gene in response to UVB irradiation. Moreover, ablation
of p53 acetylation at Lys370 by site-directed mutagenesis dramatically
suppresses UVB-induced expression of the specific p53-responsive gene as well as
cell apoptosis. Therefore, we conclude that p85α is a novel regulator of
p53-mediated response under certain stress conditions, and targeting the
p85α-dependent p53 pathway may be promising for cancer therapy. The endoplasmic reticulum (ER) consists of an interconnected, membranous network
that is the major site for the synthesis and folding of integral membrane and
secretory proteins. Within the ER lumen, protein folding is facilitated by
molecular chaperones and a variety of enzymes that ensure that polypeptides
obtain their appropriate, tertiary conformation (Dobson, C. M. (2004).
Principles of protein folding, misfolding and aggregation. Semin. Cell Dev.
Biol. 15, 3-16; Ni, M., and Lee, A. S. (2007). ER chaperones in mammalian
development and human diseases. FEBS Lett. 581, 3641-3651.). Physiological
conditions that increase protein synthesis or stimuli that disturb the processes
by which proteins obtain their native conformation, create an imbalance between
the protein-folding demand and capacity of the ER. This results in the
accumulation of unfolded or improperly folded proteins in the ER lumen and a
state of ER stress. The cellular response, referred to as the unfolded protein
response (UPR), results in activation of three linked signal transduction
pathways: PKR-like kinase (PERK), inositol requiring 1 α (IRE1α), and activating
transcription factor 6α (ATF6α) (Ron, D., and Walter, P. (2007). Signal
integration in the endoplasmic reticulum unfolded protein response. Nat. Rev.
Mol. Cell. Biol. 8, 519-529; Schroder, M., and Kaufman, R. (2005). ER stress and
the unfolded protein response. Mutat. Res./Fundam. Mol. Mech. Mutagen. 569,
29-63.). Collectively, the combined actions of these signaling cascades serve to
reduce ER stress through attenuation of translation to reduce protein synthesis
and through activation of transcriptional programs that ultimately serve to
increase ER protein-folding capacity. Recently, we and Park et al. have
characterized a novel function for the p85α and p85β subunits as modulators of
the UPR by virtue of their ability to facilitate the nuclear entry of XBP-1s
following induction of ER stress (Park, S. W., Zhou, Y., Lee, J., Lu, A., Sun,
C., Chung, J., Ueki, K., and Ozcan, U. (2010). Regulatory subunits of PI3K,
p85alpha and p85 beta, interact with XBP1 and increase its nuclear
translocation. Nat. Med. 16, 429-437; Winnay, J. N., Boucher, J., Mori, M. A.,
Ueki, K., and Kahn, C. R. (2010). A regulatory subunit of phosphoinositide
3-kinase increases the nuclear accumulation of X-box-binding protein-1 to
modulate the unfolded protein response. Nat. Med. 16, 438-445.). This chapter
describes the recently elucidated role for the regulatory subunits of PI
3-kinase as modulators of the UPR and provides methods to measure UPR pathway
activation. Phosphoinositide 3-kinase δ is upregulated in lymphocytic leukemias. Because the
p85-regulatory subunit binds to any class IA subunit, it was assumed there is a
single universal p85-mediated regulatory mechanism; however, we find
isozyme-specific inhibition by p85α. Using deuterium exchange mass spectrometry
(DXMS), we mapped regulatory interactions of p110δ with p85α. Both nSH2 and cSH2
domains of p85α contribute to full inhibition of p110δ, the nSH2 by contacting
the helical domain and the cSH2 via the C terminus of p110δ. The cSH2 inhibits
p110β and p110δ, but not p110α, implying that p110α is uniquely poised for
oncogenic mutations. Binding RTK phosphopeptides disengages the SH2 domains,
resulting in exposure of the catalytic subunit. We find that phosphopeptides
greatly increase the affinity of the heterodimer for PIP2-containing membranes
measured by FRET. DXMS identified regions decreasing exposure at membranes and
also regions gaining exposure, indicating loosening of interactions within the
heterodimer at membranes. Phosphoinositide 3-kinase (PI3K) activity is important for regulating cell
growth, survival, and motility. We report here the identification of
bromodomain-containing protein 7 (BRD7) as a p85α-interacting protein that
negatively regulates PI3K signaling. BRD7 binds to the inter-SH2 (iSH2) domain
of p85 through an evolutionarily conserved region located at the C terminus of
BRD7. Via this interaction, BRD7 facilitates nuclear translocation of p85α. The
BRD7-dependent depletion of p85 from the cytosol impairs formation of p85/p110
complexes in the cytosol, leading to a decrease in p110 proteins and in PI3K
pathway signaling. In contrast, silencing of endogenous BRD7 expression by RNAi
increases the steady-state level of p110 proteins and enhances Akt
phosphorylation after stimulation. These data suggest that BRD7 and p110 compete
for the interaction to p85. The unbound p110 protein is unstable, leading to the
attenuation of PI3K activity, which suggests how BRD7 could function as a tumor
suppressor. Phosphatidylinositol 3-kinase (PI3K) α is a heterodimeric lipid kinase that
catalyzes the conversion of phosphoinositol-4,5-bisphosphate to
phosphoinositol-3,4,5-trisphosphate. The PI3Kα signaling pathway plays an
important role in cell growth, proliferation, and survival. This pathway is
activated in numerous cancers, where the PI3KCA gene, which encodes for the
p110α PI3Kα subunit, is mutated. Its mutation often results in gain of enzymatic
activity; however, the mechanism of activation by oncogenic mutations remains
unknown. Here, using computational methods, we show that oncogenic mutations
that are far from the catalytic site and increase the enzymatic affinity
destabilize the p110α-p85α dimer. By affecting the dynamics of the protein,
these mutations favor the conformations that reduce the autoinhibitory effect of
the p85α nSH2 domain. For example, we determined that, in all of the mutants,
the nSH2 domain shows increased positional heterogeneity as compared with the
wild-type, as demonstrated by changes in the fluctuation profiles computed by
normal mode analysis of coarse-grained elastic network models. Analysis of the
interdomain interactions of the wild-type and mutants at the p110α-p85α
interface obtained with molecular dynamics simulations suggest that all of the
tumor-associated mutations effectively weaken the interactions between p110α and
p85α by disrupting key stabilizing interactions. These findings have important
implications for understanding how oncogenic mutations change the conformational
multiplicity of PI3Kα and lead to increased enzymatic activity. This mechanism
may apply to other enzymes and/or macromolecular complexes that play a key role
in cell signaling. The canonical action of the p85α regulatory subunit of phosphatidylinositol
3-kinase (PI3K) is to associate with the p110α catalytic subunit to allow
stimuli-dependent activation of the PI3K pathway. We elucidate a
p110α-independent role of homodimerized p85α in the positive regulation of PTEN
stability and activity. p110α-free p85α homodimerizes via two intermolecular
interactions (SH3:proline-rich region and BH:BH) to selectively bind
unphosphorylated activated PTEN. As a consequence, homodimeric but not monomeric
p85α suppresses the PI3K pathway by protecting PTEN from E3 ligase WWP2-mediated
proteasomal degradation. Further, the p85α homodimer enhances the lipid
phosphatase activity and membrane association of PTEN. Strikingly, we identified
cancer patient-derived oncogenic p85α mutations that target the homodimerization
or PTEN interaction surface. Collectively, our data suggest the equilibrium of
p85α monomer-dimers regulates the PI3K pathway and disrupting this equilibrium
could lead to disease development. It has been reported that p21-activated kinase 4 (PAK4) is amplified in
pancreatic cancer tissue. PAK4 is a member of the PAK family of serine/threonine
kinases, which act as effectors for several small GTPases, and has been
specifically identified to function downstream of HGF-mediated c-Met activation
in a PI3K dependent manner. However, the functionality of PAK4 in pancreatic
cancer and the contribution made by HGF signalling to pancreatic cancer cell
motility remain to be elucidated. We now find that elevated PAK4 expression is
coincident with increased expression levels of c-Met and the p85α subunit of
PI3K. Furthermore, we demonstrate that pancreatic cancer cells have a specific
motility response to HGF both in 2D and 3D physiomimetic organotypic assays;
which can be suppressed by inhibition of PI3K. Significantly, we report a
specific interaction between PAK4 and p85α and find that PAK4 deficient cells
exhibit a reduction in Akt phosphorylation downstream of HGF signalling. These
results implicate a novel role for PAK4 within the PI3K pathway via interaction
with p85α. Thus, PAK4 could be an essential player in PDAC progression
representing an interesting therapeutic opportunity. Calmodulin (CaM) and phosphatidylinositide-3 kinase (PI3Kα) are well known for
their multiple roles in a series of intracellular signaling pathways and in the
progression of several human cancers. Crosstalk between CaM and PI3Kα has been
an area of intensive research. Recent experiments have shown that in
adenocarcinoma, K-Ras4B is involved in the CaM-PI3Kα crosstalk. Based on
experimental results, we have recently put forward a hypothesis that the
coordination of CaM and PI3Kα with K-Ras4B forms a CaM-PI3Kα-K-Ras4B ternary
complex, which leads to the formation of pancreatic ductal adenocarcinoma.
However, the mechanism for the CaM-PI3Kα crosstalk is unresolved. Based on
molecular modeling and molecular dynamics simulations, here we explored the
potential interactions between CaM and the c/nSH2 domains of p85α subunit of
PI3Kα. We demonstrated that CaM can interact with the c/nSH2 domains and the
interaction details were unraveled. Moreover, the possible modes for the
CaM-cSH2 and CaM-nSH2 interactions were uncovered and we used them to construct
a complete CaM-PI3Kα complex model. The structural model of CaM-PI3Kα
interaction not only offers a support for our previous ternary complex
hypothesis, but also is useful for drug design targeted at CaM-PI3Kα
protein-protein interactions. Calmodulin (CaM) is a calcium sensor protein that directly interacts with the
dual-specificity (lipid and protein) kinase PI3Kα through the SH2 domains of the
p85 regulatory subunit. In adenocarcinomas, the CaM interaction removes the
autoinhibition of the p110 catalytic subunit of PI3Kα, leading to activation of
PI3Kα and promoting cell proliferation, survival, and migration. Here we
demonstrate that the cSH2 domain of p85α engages its two CaM-binding motifs in
the interaction with the N- and C-lobes of CaM as well as the flexible central
linker, and our nuclear magnetic resoce experiments provide structural
details. We show that in response to binding CaM, cSH2 exposes its tryptophan
residue at the N-terminal region to the solvent. Because of the flexible nature
of both CaM and cSH2, multiple binding modes of the interactions are possible.
Binding of CaM to the cSH2 domain can help release the inhibition imposed on the
p110 subunit, similar to the binding of the phosphorylated motif of RTK, or
phosphorylated CaM (pCaM), to the SH2 domains. Amino acid sequence analysis
shows that CaM-binding motifs are common in SH2 domains of non-RTKs. We
speculate that CaM can also activate these kinases through similar mechanisms. |
Computational tools for predicting allosteric pathways in proteins | CorrSite identifies potential allosteric ligand-binding sites based on motion correlation analyses between cavities. | Allosteric mechanism of proteins is essential in biomolecular signaling. An
important aspect underlying this mechanism is the communication pathways
connecting functional residues. Here, a Monte Carlo (MC) path generation
approach is proposed and implemented to define likely allosteric pathways
through generating an ensemble of maximum probability paths. The protein
structure is considered as a network of amino acid residues, and inter-residue
interactions are described by an atomistic potential function. PDZ domain
structures are presented as case studies. The analysis for bovine rhodopsin and
three myosin structures are also provided as supplementary case studies. The
suggested pathways and the residues constituting the pathways are maximally
probable and mostly agree with the previous studies. Overall, it is demonstrated
that the communication pathways could be multiple and intrinsically disposed,
and the MC path generation approach provides an effective tool for the
prediction of key residues that mediate the allosteric communication in an
ensemble of pathways and functionally plausible residues. The MCPath server is
available at http://safir.prc.boun.edu.tr/clbet_server. Allostery can occur by way of subtle cooperation among protein residues (e.g.,
amino acids) even in the absence of large conformational shifts. Dynamical
network analysis has been used to model this cooperation, helping to
computationally explain how binding to an allosteric site can impact the
behavior of a primary site many ångstroms away. Traditionally, computational
efforts have focused on the most optimal path of correlated motions leading from
the allosteric to the primary active site. We present a program called Weighted
Implementation of Suboptimal Paths (WISP) capable of rapidly identifying
additional suboptimal pathways that may also play important roles in the
transmission of allosteric signals. Aside from providing signal redundancy,
suboptimal paths traverse residues that, if disrupted through pharmacological or
mutational means, could modulate the allosteric regulation of important drug
targets. To demonstrate the utility of our program, we present a case study
describing the allostery of HisH-HisF, an amidotransferase from T. maritima
thermotiga. WISP and its VMD-based graphical user interface (GUI) can be
downloaded from http://nbcr.ucsd.edu/wisp. Allostery is a universal phenomenon that couples the information induced by a
local perturbation (effector) in a protein to spatially distant regulated sites.
Such an event can be described in terms of a large scale transmission of
information (communication) through a dynamic coupling between structurally
rigid (minimally frustrated) and plastic (locally frustrated) clusters of
residues. To elaborate a rational description of allosteric coupling, we propose
an original approach - MOdular NETwork Analysis (MONETA) - based on the analysis
of inter-residue dynamical correlations to localize the propagation of both
structural and dynamical effects of a perturbation throughout a protein
structure. MONETA uses inter-residue cross-correlations and commute times
computed from molecular dynamics simulations and a topological description of a
protein to build a modular network representation composed of clusters of
residues (dynamic segments) linked together by chains of residues (communication
pathways). MONETA provides a brand new direct and simple visualization of
protein allosteric communication. A GEPHI module implemented in the MONETA
package allows the generation of 2D graphs of the communication network. An
interactive PyMOL plugin permits drawing of the communication pathways between
chosen protein fragments or residues on a 3D representation. MONETA is a
powerful tool for on-the-fly display of communication networks in proteins. We
applied MONETA for the analysis of communication pathways (i) between the main
regulatory fragments of receptors tyrosine kinases (RTKs), KIT and CSF-1R, in
the native and mutated states and (ii) in proteins STAT5 (STAT5a and STAT5b) in
the phosphorylated and the unphosphorylated forms. The description of the
physical support for allosteric coupling by MONETA allowed a comparison of the
mechanisms of (a) constitutive activation induced by equivalent mutations in two
RTKs and (b) allosteric regulation in the activated and non-activated STAT5
proteins. Our theoretical prediction based on results obtained with MONETA was
validated for KIT by in vitro experiments. MONETA is a versatile analytical and
visualization tool entirely devoted to the understanding of the
functioning/malfunctioning of allosteric regulation in proteins - a crucial
basis to guide the discovery of next-generation allosteric drugs. Allostery is the phenomenon in which a ligand binding at one site affects other
sites in the same macromolecule. Allostery has important roles in many
biological processes. Theoretically, all nonfibrous proteins are potentially
allosteric. However, few allosteric proteins have been validated, and the
identification of novel allosteric sites remains a challenge. The motion of
residues and subunits underlies protein function; therefore, we hypothesized
that the motions of allosteric and orthosteric sites are correlated. We utilized
a data set of 24 known allosteric sites from 23 monomer proteins to calculate
the correlations between potential ligand-binding sites and corresponding
orthosteric sites using a Gaussian network model (GNM). Most of the known
allosteric site motions showed high correlations with corresponding orthosteric
site motions, whereas other surface cavities did not. These high correlations
were robust when using different structural data for the same protein, such as
structures for the apo state and the orthosteric effector-binding state, whereas
the contributions of different frequency modes to motion correlations depend on
the given protein. The high correlations between allosteric and orthosteric site
motions were also observed in oligomeric allosteric proteins. We applied motion
correlation analysis to predict potential allosteric sites in the 23 monomer
proteins, and some of these predictions were in good agreement with published
experimental data. We also performed motion correlation analysis to identify a
novel allosteric site in 15-lipoxygenase (an enzyme in the arachidonic acid
metabolic network) using recently reported activating compounds. Our analysis
correctly identified this novel allosteric site along with two other sites that
are currently under experimental investigation. Our study demonstrates that the
motions of allosteric sites are highly correlated with the motions of
orthosteric sites. Our correlation analysis method provides new tools for
predicting potential allosteric sites. Allostery, or allosteric regulation, is the phenomenon in which protein
functional activity is altered by the binding of an effector at an allosteric
site that is topographically distinct from the orthosteric, active site. As one
of the most direct and efficient ways to regulate protein function, allostery
has played a fundamental role in innumerable biological processes of all living
organisms, including enzyme catalysis, signal transduction, cell metabolism, and
gene transcription. It is thus considered as "the second secret of life". The
abnormality of allosteric communication networks between allosteric and
orthosteric sites is associated with the pathogenesis of human diseases.
Allosteric modulators, by attaching to structurally diverse allosteric sites,
offer the potential for differential selectivity and improved safety compared
with orthosteric drugs that bind to conserved orthosteric sites. Harnessing
allostery has thus been regarded as a novel strategy for drug discovery. Despite
much progress having been made in the repertoire of allostery since the turn of
the millennium, the identification of allosteric drugs for therapeutic targets
and the elucidation of allosteric mechanisms still present substantial
challenges. These challenges are derived from the difficulties in the
identification of allosteric sites and mutations, the assessment of allosteric
protein-modulator interactions, the screening of allosteric modulators, and the
elucidation of allosteric mechanisms in biological systems. To address these
issues, we have developed a panel of allosteric services for specific allosteric
applications over the past decade, including (i) the creation of the Allosteric
Database, with the aim of providing comprehensive allosteric information such as
allosteric proteins, modulators, sites, pathways, etc., (ii) the construction of
the ASBench benchmark of high-quality allosteric sites for the development of
computational methods for predicting allosteric sites, (iii) the development of
Allosite and AllositePro for the prediction of the location of allosteric sites
in proteins, (iv) the development of the Alloscore scoring function for the
evaluation of allosteric protein-modulator interactions, (v) the development of
Allosterome for evolutionary analysis of query allosteric sites/modulators
within the human proteome, (vi) the development of AlloDriver for the prediction
of allosteric mutagenesis, and (vii) the development of AlloFinder for the
virtual screening of allosteric modulators and the investigation of allosteric
mechanisms. Importantly, we have validated computationally predicted allosteric
sites, mutations, and modulators in the real cases of sirtuin 6, casein kinase
2α, phosphodiesterase 10A, and signal transduction and activation of
transcription 3. Furthermore, our developed allosteric methods have been widely
exploited by other users around the world for allosteric research. Therefore,
these allosteric services are expected to expedite the discovery of allosteric
drugs and the investigation of allosteric mechanisms. While the pervasiveness of allostery in proteins is commonly accepted, we
further show the generic nature of allosteric mechanisms by analyzing here
transmembrane ion-channel viroporin 3a and RNA-dependent RNA polymerase (RdRp)
from SARS-CoV-2 along with metabolic enzymes isocitrate dehydrogenase 1 (IDH1)
and fumarate hydratase (FH) implicated in cancers. Using the previously
developed structure-based statistical mechanical model of allostery (SBSMMA), we
share our experience in analyzing the allosteric signaling, predicting latent
allosteric sites, inducing and tuning targeted allosteric response, and
exploring the allosteric effects of mutations. This, yet incomplete list of
phenomenology, forms a complex and unique allosteric territory of protein
function, which should be thoroughly explored. We propose a generic
computational framework, which not only allows one to obtain a comprehensive
allosteric control over proteins but also provides an opportunity to approach
the fragment-based design of allosteric effectors and drug candidates. The
advantages of allosteric drugs over traditional orthosteric compounds,
complemented by the emerging role of the allosteric effects of mutations in the
expansion of the cancer mutational landscape and in the increased mutability of
viral proteins, leave no choice besides further extensive studies of allosteric
mechanisms and their biomedical implications. |
What are the classic signs of a basilar skull fracture? | Basilar skull fractures are fractures of the lower part of the skull. The four classic signs are:
1. Periorbital ecchymosis (“raccoon eyes”).
2. Postauricular ecchymosis (Battle sign).
3. CSF otorrhea or rhinorrhea (leakage of CSF, which is clear in appearance, from the ears or nose).
4. Hemotympanum (blood behind the eardrum). | Forty-six cases of basilar skull fractures in children were reviewed to
determine the incidence of CNS infection following injury and the possible value
of antimicrobial chemoprophylaxis. The clinical course of the children who were
treated with antibiotics was compared with that of patients who received no
antimicrobial therapy. Included in the study were patients with hemotympanum
alone or with hemotympanum plus additional clinical or roentgenographic signs of
basilar skull fracture; patients with tympanic membrane perforation without
otorrhea but with blood in the auditory canal; and children with either otorrhea
or rhinorrhea. Acute, delayed, or recurrent infection of the CNS did not develop
in any of the patients. This study is the first of its kind presented in
children. It would seem on the basis of the present series that the systematic
use of antibiotic prophylaxis in children with hemotympanum following basilar
skull fractures is unwarranted and that children with other signs of basilar
skull fractures may have an equally small risk of meningitis following injury. A prospective study was performed on 4,262 consecutive patients who had had
skull examinations for recent head trauma. Clinical signs and symptoms and
patient history were correlated with skull fractures and intracranial sequelae
as identified on CT studies, in order to evaluate the predictive value of each
clinical finding and to identify high-yield referral criteria. Ninety-seven
skull fractures (3%) and 32 intracranial sequelae (0.7%) were observed. All the
intracranial complications were observed in patients with fractures and with
altered consciousness of some degrees (Glasgow Coma Scale score less than 13).
Most patients were asymptomatic (41%) or showed "low risk" symptoms (29%): among
them, neither fractures nor complications were observed. High-risk clinical
signs, mainly expressing basilar fractures (as rhinorrhea, otorrhea, focal
neurologic signs, retroauricular hematoma) demonstrated high predictive value
(100%) for intracranial sequelae. Other "moderate risk" findings for
intracranial injury--i.e. loss of consciousness at any time, antegrade or
retrograde amnesia, multiple trauma, and possible skull penetration--showed a
high correlation with skull fractures and a slightly lower one with intracranial
sequelae. The most predictive finding for brain injury was the depressed level
of consciousness: brain injuries were never observed in fully conscious
patients; in altered consciousness with GCS 15-13 we observed 4% of skull
fractures with no sequelae; at GCS values 12-9, 61% of skull fractures and 20%
of sequelae were present, whereas at GCS less than 8, 100% of complicated
fracture were observed. The finding of skull fracture showed 33% of predictivity
for brain damage, which was, however, always associated with "high or moderate
risk" clinical signs. Therefore, the authors suggest some guidelines for the
management of patients with recent head trauma, including referral criteria for
X-rays or CT studies, based on signs and symptoms with high, intermediate and
low risk of developing intracranial sequelae. In this paper we are reporting a retrospective study of patients under 18 years
of age managed at the Los Angeles County/University of Southern California
Medical Center from January 1979 through December 1987 with the diagnosis of
basilar skull fracture. Sixty-two patients with basilar skull fractures were
admitted during that 7 1/2 year period. The most common etiology was pedestrain
versus vehicle accidents (42%), followed by falls (27%), vehicle accidents
(23%), and being hit by an object (8%). The most common physical findings were
hemotympanum (58%) and bleeding in the ear canals (47%). Thirty-four percent of
the patients complained of hearing loss. Cerebrospinal fluid otorrhea was noted
in 16 patients (26%), while only 1 patient had cerebrospinal fluid rhinorrhea.
Facial nerve paralysis was present in 8 patients (13%). Vestibular symptoms were
rare. Sixty-three percent of the patients had the diagnosis confirmed by
radiography. The clinical presentation, complications, management and outcome of
basilar skull fractures in the pediatric population are discussed. A 56-year-old woman presented with retrograde amnesia and confusion at the
Emergency Department after falling down the stairs. Physical examination
revealed a bilateral periorbital hematoma (raccoon eyes) and bilateral
retroauricular ecchymosis, both strongly indicative of a basilar skull fracture. Although clinical signs for the diagnosis of basilar skull fracture (BSF) are
ambiguous, they are widely used to make decisions on initial interventions
involving trauma patients. We aimed to assess the performance of early and late
(within 48 hr posttrauma) signs for BSF diagnosis and to verify the correlation
between the presence of these signs and head injury severity. We conducted a
prospectively designed follow-up study at a referral hospital for trauma care in
Sao Paulo, Brazil, and performed structured observations for 48 hr post-blunt
head injury in patients aged 12 years or older. The following signs of BSF were
considered: raccoon eyes, Battle's sign, otorrhea, and rhinorrhea. Among the 136
enrolled patients (85.3% male; mean age 40 ± 21.4 years), 28 patients (20.6%)
had BSF. The clinical signs for the early or late detection of BSF had low
accuracy (55.9% vs. 43.4%), specificity (52.8% vs. 30.5%), and positive
predictive value (25.7% vs. 27.1%). However, the presence of these signs was
correlated to head injury severity, indicated by the Glasgow Coma Scale (p =
.041) and Maximum Abbreviated Injury Scale-Head region (p = .002). In view of
the low accuracy of these signs, resulting low clinical value of their presence,
and their high sensitivity in the late stage, the study results contraindicate
the value of BSF signs for making decisions about using the nasal route for the
introduction of catheters and tubes in initial trauma care. Publisher: KLINISCHES PROBLEM: Bei Schädelbasisfrakturen handelt es sich um
Frakturen des unteren Abschnitts des Hirnschädels. Sie machen ca. 20 % aller
Schädelfrakturen aus und werden vor allem durch Hochranztraumen und Stürze aus
großer Höhe verursacht. Sie können in Abhängigkeit ihrer genauen Lokalisation in
frontobasale, laterobasale und frontolaterale Frakturen unterteilt werden.
Mögliche klinische Zeichen sind das Vorliegen einer Rhino- und Otoliquorrhoe,
Monokel- und Brillenhämatome, retroaurikuläre Ekchymose (sog. Battle-Zeichen)
sowie Hirnnervenausfälle. Ferner kann es bei den Felsenbeinfrakturen zu einer
Schallleitungsstörung, Schallempfindungsstörung sowie zu Schwindel und Übelkeit
aufgrund eines möglichen Ausfalls des Labyrinths kommen. EMPFEHLUNGEN FüR DIE
PRAXIS: Bei klinischen Zeichen auf Vorliegen einer Schädelbasisfraktur,
neurologischen Ausfällen oder eingeschränktem Bewusstsein (GCS < 15) sollte eine
Computertomographie (CT) zum Ausschluss einer Schädelbasisfraktur und
begleitenden Pathologien erfolgen. Zusätzlich sollte bei Verdacht auf eine
Gefäßverletzung eine CT-Angiographie erfolgen. Die Therapie erfolgt in der Regel
interdisziplinär und richtet sich insbesondere nach den begleitenden
Verletzungen und möglichen Komplikationen. Häufig ist ein rein konservatives
Vorgehen mit engmaschigen Kontrollen (u. a. mit Bildgebung) ausreichend. Ein
operatives Vorgehen dient der Behandlung von möglichen Komplikationen, wie z. B.
ausgeprägte intrazerebrale Blutungen. |
Which biomarkers are currently used for Duchenne Muscular Dystrophy? | MRI measurements can be used as biomarkers of disease severity in ambulant patients with DMD. malate dehydrogenase 2 as candidate prognostic biomarker for Duchenne muscular dystrophy | Extracellular microRNAs (miRNAs) are promising biomarkers of the inherited
muscle wasting condition Duchenne muscular dystrophy, as they allow non-invasive
monitoring of either disease progression or response to therapy. In this study,
serum miRNA profiling reveals a distinct extracellular miRNA signature in
dystrophin-deficient mdx mice, which shows profound dose-responsive restoration
following dystrophin rescue. Extracellular dystrophy-associated miRNAs
(dystromiRs) show dynamic patterns of expression that mirror the progression of
muscle pathology in mdx mice. Expression of the myogenic miRNA, miR-206 and the
myogenic transcription factor myogenin in the tibialis anterior muscle were
found to positively correlate with serum dystromiR levels, suggesting that
extracellular miRNAs are indicators of the regenerative status of the
musculature. Similarly, extracellular dystromiRs were elevated following
experimentally-induced skeletal muscle injury and regeneration in non-dystrophic
mice. Only a minority of serum dystromiRs were found in extracellular vesicles,
whereas the majority were protected from serum nucleases by association with
protein/lipoprotein complexes. In conclusion, extracellular miRNAs are dynamic
indices of pathophysiological processes in skeletal muscle. Creatine kinase has been utilized as a diagnostic marker for Duchenne muscular
dystrophy (DMD), but it correlates less well with the DMD pathological
progression. In this study, we hypothesized that muscle-specific microRNAs
(miR-1, -133, and -206) in serum may be useful for monitoring the DMD
pathological progression, and explored the possibility of these miRNAs as
potential non-invasive biomarkers for the disease. By using real-time
quantitative reverse transcription-polymerase chain reaction in a randomized and
controlled trial, we detected that miR-1, -133, and -206 were significantly
over-expressed in the serum of 39 children with DMD (up to 3.20 ± 1.20, 2(-ΔΔCt)
): almost 2- to 4-fold enriched in comparison to samples from the healthy
controls (less than 1.15 ± 0.34, 2(-ΔΔCt) ). To determine whether these miRNAs
were related to the clinical features of children with DMD, we analyzed the
associations compared to creatine kinase. There were very good inverse
correlations between the levels of these miRNAs, especially miR-206, and
functional performances: high levels corresponded to low muscle strength, muscle
function, and quality of life. Moreover, by receiver operating characteristic
curves analyses, we revealed that these miRNAs, especially miR-206, were able to
discriminate DMD from controls. Thus, miR-206 and other muscle-specific miRNAs
in serum are useful for monitoring the DMD pathological progression, and hence
as potential non-invasive biomarkers for the disease. There has been a
long-standing need for reliable, non-invasive biomarkers for Duchenne muscular
dystrophy (DMD). We found that the levels of muscle-specific microRNAs,
especially miR-206, in the serum of DMD were 2- to 4-fold higher than in the
controls. High levels corresponded to low muscle strength, muscle function, and
quality of life (QoL). These miRNAs were able to discriminate DMD from controls
by receiver operating characteristic (ROC) curves analyses. Thus, miR-206 and
other muscle-specific miRNAs are useful as non-invasive biomarkers for DMD. Diagnosis of muscular dystrophies is currently based on invasive methods
requiring muscle biopsies or blood tests. The aim of the present study was to
identify urinary biomarkers as a diagnostic tool for muscular dystrophies. Here,
the urinary proteomes of Duchenne muscular dystrophy (DMD) patients and healthy
donors were compared with a bottom-up proteomic approach. Label-free analysis of
more than 1100 identified proteins revealed that 32 of them were differentially
expressed between healthy controls and DMD patients. Among these 32 proteins,
titin showed the highest fold change between healthy subjects and DMD patients.
Interestingly, most of the sequenced peptides belong to the N-terminal and
C-terminal parts of titin, and the presence of the corresponding fragments in
the urine of DMD patients was confirmed by Western blot analysis. Analysis of a
large cohort of DMD patients and age-matched controls (a total of 104
individuals aged from 3 to 20 years) confirmed presence of the N-ter fragment in
all but two patients. In two DMD patients aged 16 and 20 years this fragment was
undetectable and two healthy controls of 16 and 19 years with serum CK >800 IU/L
demonstrated a low level of the fragment. N- and C-terminal titin fragments were
also detected in urine from patients with other muscular dystrophies such as
Becker muscular dystrophy and Limb-girdle muscular dystrophy (type 1D, 2D and
2J) but not in neurogenic spinal muscular atrophy. They were also present in
urine of dystrophin-deficient animal models (GRMD dogs and mdx mice). Titin is
the first urinary biomarker that offers the possibility to develop a simple,
non-invasive and easy-to-use test for pre-screening of muscular dystrophies, and
may also prove to be useful for the non-invasive follow up of DMD patients under
treatment. Author information:
(1)Research Center in Technology and Design Assistance of Jalisco State (CIATEJ,
AC), National Council of Science and Technology (CONACYT), Guadalajara 44270,
Mexico. [email protected].
(2)National Medical Centre \"20 de Noviembre\", Institute for Social Security of
State Workers, Mexico City 03100, Mexico. [email protected].
(3)National Medical Centre \"20 de Noviembre\", Institute for Social Security of
State Workers, Mexico City 03100, Mexico. [email protected].
(4)National Institute of Rehabilitation, Mexico City 14389, Mexico.
[email protected].
(5)Faculty of Medicine, National Autonomous University of Mexico, Mexico City
04510, Mexico. [email protected].
(6)Research Center in Technology and Design Assistance of Jalisco State (CIATEJ,
AC), National Council of Science and Technology (CONACYT), Guadalajara 44270,
Mexico. [email protected].
(7)Studies Section of Postgraduate and Research, School of Medicine, National
Polytechnic Institute, Mexico City 11340, Mexico. [email protected].
(8)National Medical Centre \"20 de Noviembre\", Institute for Social Security of
State Workers, Mexico City 03100, Mexico. [email protected].
(9)National Institute of Rehabilitation, Mexico City 14389, Mexico.
[email protected].
(10)Asociación de Distrofia Muscular de Occidente A.C., Guadalajara 44380,
Mexico. [email protected].
(11)Mexican Institute of Social Security-CMNO, Guadalajara 44340, Mexico.
[email protected].
(12)Faculty of Medicine, Autonomous University of Guadalajara, Guadalajara
45129, Mexico. [email protected].
(13)National Medical Centre \"20 de Noviembre\", Institute for Social Security
of State Workers, Mexico City 03100, Mexico. [email protected].
(14)National Medical Centre \"20 de Noviembre\", Institute for Social Security
of State Workers, Mexico City 03100, Mexico. [email protected]. BACKGROUND: Duchenne Muscular Dystrophy (DMD) is a severe, progressive,
neuromuscular disorder of childhood. While a number of serum factors have been
identified as potential biomarkers of DMD, none, as yet, are proteins within the
dystrophin-associated glycoprotein (DAG) complex.
OBJECTIVE: We have developed an immobilized serum ELISA assay to measure the
expression of a constitutively cleaved and secreted component of the DAG
complex, the N-terminal domain of α dystroglycan (αDG-N), and assayed relative
expression in serum from muscular dystrophy patients and normal controls.
METHODS: ELISAs of immobilized patient or mouse serum and Western blots were
used to assess αDG-N expression.
RESULTS: Immobilization of diluted serum on ELISA plates was important for this
assay, as methods to measure serum αDG-N in solution were less robust. αDG-N
ELISA signals were significantly reduced in DMD serum (27±3% decrease, n = 9,
p < 0.001) relative to serum from otherwise normal controls (n = 38), and
calculated serum αDG-N concentrations were reduced in DMD relative to normal
(p < 0.01) and Becker Muscular Dystrophy (n = 11, p < 0.05) patient serum. By
contrast, ELISA signals from patients with Inclusion Body Myositis were not
different than normal (4±3% decrease, n = 8, p = 0.99). αDG-N serum signals were
also significantly reduced in utrophin-deficient mdx mice as compared to mdx and
wild type mice.
CONCLUSIONS: Our results are the first demonstration of a component of the DAG
complex as a potential serum biomarker in DMD. Such a serum measure could be
further developed as a tool to help reflect overall muscle DAG complex
expression or stability. Circulating microRNAs (miRs/miRNAs) are being used as non-invasive biomarkers
for diagnosis, prognosis and efficiency of clinical trials. However, to exploit
their potential it is necessary to improve and standardize their detection. In a
previous study, we identified two microRNAs, miR-30c and miR-181a, that appear
to be key regulators of muscular dystrophy. We hypothesized that they could
represent useful biomarkers of Duchenne and Becker muscular dystrophies (DMD and
BMD). The objective of this study was to assess the absolute levels of miR-30c
and miR-181a in sera of DMD and BMD patients using digital PCR (a robust
technique for precise and direct quantification of small amounts of nucleic
acids without standard curves and external references), and investigate the
correlation between miR-30c and miR-181a expressions and several clinical
parameters. Our results show that the serum levels of miR-30c and miR-181a
increased 7- and 6-fold respectively in DMD patients (n = 21, 2-14 years,
ambulant), and 7-fold in BMD patients (n = 5, 9-15 years) compared to controls
(n = 22, 2-14 years). No association between miRNA levels and age or
corticosteroid treatment was detected in DMD. However, there was a trend towards
higher levels of miR-30c in DMD patients with better preserved motor function
according to various motor scales and timed tests. We demonstrate that digital
PCR is a useful technique for accurate absolute quantification of microRNAs in
sera of DMD/BMD patients. We propose miR-30c and miR-181a as reliable serum
diagnostic biomarkers for DMD and BMD and miR-30c as a potential novel biomarker
to assess disease severity in DMD. Despite promising therapeutic avenues, there is currently no effective treatment
for Duchenne muscular dystrophy (DMD), a lethal monogenic disorder caused by the
loss of the large cytoskeletal protein, dystrophin. A highly promising approach
to therapy, applicable to all DMD patients irrespective to their genetic defect,
is to modulate utrophin, a functional paralogue of dystrophin, able to
compensate for the primary defects of DMD restoring sarcolemmal stability. One
of the major difficulties in assessing the effectiveness of therapeutic
strategies is to define appropriate outcome measures. In the present study, we
utilised an aptamer based proteomics approach to profile 1,310 proteins in
plasma of wild-type, mdx and Fiona (mdx overexpressing utrophin) mice.
Comparison of the C57 and mdx sera revealed 83 proteins with statistically
significant >2 fold changes in dystrophic serum abundance. A large majority of
previously described biomarkers (ANP32B, THBS4, CAMK2A/B/D, CYCS, CAPNI) were
normalised towards wild-type levels in Fiona animals. This work also identified
potential mdx markers specific to increased utrophin (DUS3, TPI1) and highlights
novel mdx biomarkers (GITR, MYBPC1, HSP60, SIRT2, SMAD3, CNTN1). We define a
panel of putative protein mdx biomarkers to evaluate utrophin based strategies
which may help to accelerate their translation to the clinic. OBJECTIVE: To provide evidence for quantitative magnetic resoce (qMR)
biomarkers in Duchenne muscular dystrophy by investigating the relationship
between qMR measures of lower extremity muscle pathology and functional
endpoints in a large ambulatory cohort using a multicenter study design.
METHODS: MR spectroscopy and quantitative imaging were implemented to measure
intramuscular fat fraction and the transverse magnetization relaxation time
constant (T2) in lower extremity muscles of 136 participants with Duchenne
muscular dystrophy. Measures were collected at 554 visits over 48 months at one
of three imaging sites. Fat fraction was measured in the soleus and vastus
lateralis using MR spectroscopy, while T2 was assessed using MRI in eight lower
extremity muscles. Ambulatory function was measured using the 10m walk/run,
climb four stairs, supine to stand, and six minute walk tests.
RESULTS: Significant correlations were found between all qMR and functional
measures. Vastus lateralis qMR measures correlated most strongly to functional
endpoints (|ρ| = 0.68-0.78), although measures in other rapidly progressing
muscles including the biceps femoris (|ρ| = 0.63-0.73) and peroneals (|ρ| =
0.59-0.72) also showed strong correlations. Quantitative MR biomarkers were
excellent indicators of loss of functional ability and correlated with
qualitative measures of function. A VL FF of 0.40 was an approximate lower
threshold of muscle pathology associated with loss of ambulation.
DISCUSSION: Lower extremity qMR biomarkers have a robust relationship to
clinically meaningful measures of ambulatory function in Duchenne muscular
dystrophy. These results provide strong supporting evidence for qMR biomarkers
and set the stage for their potential use as surrogate outcomes in clinical
trials. Duchenne muscular dystrophy (DMD) is a fatal inherited genetic disorder that
results in progressive muscle weakness and ultimately loss of ambulation,
respiratory failure and heart failure. Cardiac MRI (MRI) plays an increasingly
important role in the diagnosis and clinical care of boys with DMD and
associated cardiomyopathies. Conventional cardiac MRI biomarkers permit
measurements of global cardiac function and presence of fibrosis, but changes in
these measures are late manifestations. Emerging MRI biomarkers of myocardial
function and structure include the estimation of rotational mechanics and
regional strain using MRI tagging; T1-mapping; and T2-mapping, a marker of
inflammation, edema and fat. These emerging biomarkers provide earlier insights
into cardiac involvement in DMD, improving patient care and aiding the
evaluation of emerging therapies. BACKGROUND: Duchenne muscular dystrophy (DMD) is a fatal disease for which no
cure is available. Clinical trials have shown to be largely underpowered due to
inter-individual variability and noisy outcome measures. The availability of
biomarkers able to anticipate clinical benefit is highly needed to improve
clinical trial design and facilitate drug development.
METHODS: In this study, we aimed to appraise the value of protein biomarkers to
predict prognosis and monitor disease progression or treatment outcome in
patients affected by DMD. We collected clinical data and 303 blood samples from
157 DMD patients in three clinical centres; 78 patients contributed multiple
blood samples over time, with a median follow-up time of 2 years. We employed
linear mixed models to identify biomarkers that are associated with disease
progression, wheelchair dependency, and treatment with corticosteroids and
performed survival analysis to find biomarkers whose levels are associated with
time to loss of ambulation.
RESULTS: Our analysis led to the identification of 21 proteins whose levels
significantly decrease with age and nine proteins whose levels significantly
increase. Seven of these proteins are also differentially expressed in
non-ambulant patients, and three proteins are differentially expressed in
patients treated with glucocorticosteroids. Treatment with corticosteroids was
found to partly counteract the effect of disease progression on two biomarkers,
namely, malate dehydrogenase 2 (MDH2, P = 0.0003) and ankyrin repeat domain 2 (P
= 0.0005); however, patients treated with corticosteroids experienced a further
reduction on collagen 1 serum levels (P = 0.0003), especially following
administration of deflazacort. A time to event analysis allowed to further
support the use of MDH2 as a prognostic biomarker as it was associated with an
increased risk of wheelchair dependence (P = 0.0003). The obtained data support
the prospective evaluation of the identified biomarkers in natural history and
clinical trials as exploratory biomarkers.
CONCLUSIONS: We identified a number of serum biomarkers associated with disease
progression, loss of ambulation, and treatment with corticosteroids. The
identified biomarkers are promising candidate prognostic and surrogate
biomarkers, which may support drug developers if confirmed in prospective
studies. The serum levels of MDH2 are of particular interest, as they correlate
with disease stage and response to treatment with corticosteroids, and are also
associated with the risk of wheelchair dependency and pulmonary function. OBJECTIVE: To assess the evidence of a relationship between muscle MRI and
disease severity in Duchenne muscular dystrophy (DMD).
METHODS: We conducted a systematic review of studies that analyzed correlations
between MRI measurements and motor function in patients with DMD. PubMed,
Cochrane, Scopus, and Web of Science were searched using relevant keywords and
inclusion/exclusion criteria (January 1, 1990-January 31, 2019). We evaluated
article quality using the Joanna Briggs Institute scale. Information regarding
the samples included, muscles evaluated, MRI protocols and motor function tests
used was collected from each article. Correlations between MRI measurements and
motor function were reported exhaustively.
RESULTS: Seventeen of 1,629 studies identified were included. Most patients
included were ambulant with a mean age of 8.9 years. Most studies evaluated
lower limb muscles. Moderate to excellent correlations were found between MRI
measurements and motor function. The strongest correlations were found for
quantitative MRI measurements such as fat fraction or mean T2. Correlations were
stronger for lower leg muscles such as soleus. One longitudinal study reported
that changes in soleus mean T2 were highly correlated with changes in motor
function.
CONCLUSION: The findings of this systematic review showed that MRI measurements
can be used as biomarkers of disease severity in ambulant patients with DMD.
Guidelines are proposed to help clinicians choose the most appropriate MRI
measurements and muscles to evaluate. Studies exploring upper limb muscles,
other stages of the disease, and sensitivity of measurements to change are
needed. BACKGROUND: Duchenne Muscular Dystrophy is a severe, incurable disorder caused
by mutations in the dystrophin gene. The disease is characterized by decreased
muscle function, impaired muscle regeneration and increased inflammation. In a
clinical context, muscle deterioration, is evaluated using physical tests and
analysis of muscle biopsies, which fail to accurately monitor the disease
progression.
OBJECTIVES: This study aims to confirm and asses the value of blood protein
biomarkers as disease progression markers using one of the largest longitudinal
collection of samples.
METHODS: A total of 560 samples, both serum and plasma, collected at three
clinical sites are analyzed using a suspension bead array platform to assess 118
proteins targeted by 250 antibodies in microliter amount of samples.
RESULTS: Nine proteins are confirmed as disease progression biomarkers in both
plasma and serum. Abundance of these biomarkers decreases as the disease
progresses but follows different trajectories. While carbonic anhydrase 3,
microtubule associated protein 4 and collagen type I alpha 1 chain decline
rather constantly over time, myosin light chain 3, electron transfer
flavoprotein A, troponin T, malate dehydrogenase 2, lactate dehydrogenase B and
nestin plateaus in early teens. Electron transfer flavoprotein A, correlates
with the outcome of 6-minutes-walking-test whereas malate dehydrogenase 2
together with myosin light chain 3, carbonic anhydrase 3 and nestin correlate
with respiratory capacity.
CONCLUSIONS: Nine biomarkers have been identified that correlate with disease
milestones, functional tests and respiratory capacity. Together these biomarkers
recapitulate different stages of the disorder that, if validated can improve
disease progression monitoring. Recently, several promising treatments have emerged for neuromuscular disorders,
highlighting the need for robust biomarkers for monitoring therapeutic efficacy
and maintece of the therapeutic effect. Several studies have proposed
circulating and tissue biomarkers, but none of them has been validated to
monitor acute and long-term drug response. We previously described how the
myostatin (MSTN) level is naturally downregulated in several neuromuscular
diseases, including Duchenne muscular dystrophy (DMD). Here, we show that the
dystrophin-deficient Golden Retriever muscular dystrophy (GRMD) dog model also
presents an intrinsic loss of Mstn production in muscle. The abnormally low
levels of Mstn observed in the GRMD dog puppies at 2 months were partially
rescued at both mRNA and protein level after adeno-associated virus
(AAV)-microdystrophin treatment in a dose-dependent manner. These results show
that circulating Mstn is a robust and reliable quantitative biomarker, capable
of measuring a therapeutic response to pharmaco-gene therapy in real time in the
neuromuscular system, as well as a quantitative means for non-invasive follow-up
of a therapeutic effect. Moreover, a 2-year follow-up also suggests that Mstn
could be a longitudinal monitoring tool to follow maintece or decrease of the
therapeutic effect. PURPOSE: Duchenne muscular dystrophy (DMD) is currently the most commonly
diagnosed form of muscular dystrophy due to mutations in the dystrophin gene.
However, its pathological process remains unknown and there is a lack of
specific molecular biomarkers. The aim of our study is to explore key regulatory
connections underlying the progression of DMD.
MATERIALS AND METHODS: The gene expression profile dataset GSE38417 of DMD was
obtained from the Gene Expression Omnibus (GEO) database. The differentially
expressed genes (DEGs) between DMD patients and healthy controls were screened
using geo2R, followed by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene
Ontology (GO) pathway enrichment analyses. Then a protein-protein interaction
(PPI) network and sub-network of modules were constructed. To investigate the
regulatory network underlying DMD, a global triple network including miRNAs,
mRNAs and transcription factors (TFs) was constructed.
RESULTS: A total of 1811 DEGs were found between the DMD and control groups,
among which HERC5, SKP2 and FBXW5 were defined as hub genes with a degree of
connectivity >35 in the PPI network. Furthermore, the five TFs ZNF362, ATAT1,
SPI1, TCF12 and ABCF2, as well as the eight miRNAs miR-124a, miR-200b/200c/429,
miR-19a/b, miR-23a/b, miR-182, miR-144, miR-498 and miR-18a/b were identified as
playing crucial roles in the molecular pathogenesis of DMD.
CONCLUSIONS: This paper provides a comprehensive perspective on the
miRNA-TF-mRNA co-regulatory network underlying DMD, although the bioinformatic
findings need further validation in future studies. Aim: Evaluate the utility of glutamate dehydrogenase (GLDH) and cardiac troponin
I as safety biomarkers, and creatine kinase and muscle injury panel as muscle
health biomarkers in Duchenne muscular dystrophy. Patients & methods: Data were
collected during a Phase II trial of domagrozumab. Results: GLDH was a more
specific biomarker for liver injury than alanine aminotransferase. Cardiac
troponin I elevations were variable and not sustained, limiting its
applicability as a biomarker. Muscle injury panel biomarkers were no more
informative than creatine kinase as a muscle health biomarker. Conclusion:
Results support the use of GLDH as a specific biomarker for liver injury in
patients with Duchenne muscular dystrophy. Clinical trial registration:
ClinicalTrials.gov, NCT02310763. |
What links lipid metabolism pathways to ALS? | Dysregulation of lipid metabolism is observed early in the spinal cord of the SOD1 ALS mouse model, and abnormal levels of cholesterol and other lipids are observed in the blood and CNS of ALS patients. In addition, higher blood high density lipoprotein and apolipoprotein A1 levels are associated with reduced risk of developing ALS. | Amyotrophic lateral sclerosis (ALS) is one of the most common adult-onset
neurodegenerative diseases, with progressive paralysis and muscle atrophy. The
exact pathogenic mechanism remains unknown, but recent evidence suggests that
differential gene expression and gene splicing may play a significant role. We
used Affymetrix GeneChip Mouse Exon 1.0 ST Array to investigate the expression
profiling of lumbar spinal cord samples from SOD1-G93A transgenic mice, the
widely used animal model of ALS. The de-regulated genes analyzed either from the
expression level or from the alternative splicing level both showed overlapping
GO categories and pathway mapping. Our findings indicate that cell adhesion,
immune-inflammation response and lipid metabolism all play important roles in
the onset of ALS. Detailed analysis by RT-PCR of key genes confirmed the
experimental results of microarrays. These results suggest a multi-factor
mechanism in ALS development. Motor neuron diseases (MNDs) are characterized by selective death of motor
neurons and include mainly adult-onset amyotrophic lateral sclerosis (ALS) and
spinal muscular atrophy (SMA). Neurodegeneration is not the single pathogenic
event occurring during disease progression. There are multiple lines of evidence
for the existence of defects in lipid metabolism at peripheral level. For
instance, hypermetabolism is well characterized in ALS, and dyslipidemia
correlates with better prognosis in patients. Lipid metabolism plays also a role
in other MNDs. In SMA, misuse of lipids as energetic nutrients is described in
patients and in related animal models. The composition of structural lipids in
the central nervous system is modified, with repercussion on membrane fluidity
and on cell signaling mediated by bioactive lipids. Here, we review the main
epidemiologic and mechanistic findings that link alterations of lipid metabolism
and motor neuron degeneration, and we discuss the rationale of targeting these
modifications for therapeutic management of MNDs. Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset disease characterized
by upper and lower motor neuron degeneration, muscle wasting and paralysis.
Growing evidence suggests a link between changes in lipid metabolism and ALS.
Here, we used UPLC/TOF-MS to survey the lipidome in SOD1(G86R) mice, a model of
ALS. Significant changes in lipid expression were evident in spinal cord and
skeletal muscle before overt neuropathology. In silico analysis also revealed
appreciable changes in sphingolipids including ceramides and glucosylceramides
(GlcCer). HPLC analysis showed increased amounts of GlcCer and downstream
glycosphingolipids (GSLs) in SOD1(G86R) muscle compared with wild-type
littermates. Glucosylceramide synthase (GCS), the enzyme responsible for GlcCer
biosynthesis, was up-regulated in muscle of SOD1(G86R) mice and ALS patients,
and in muscle of wild-type mice after surgically induced denervation.
Conversely, inhibition of GCS in wild-type mice, following transient peripheral
nerve injury, reversed the overexpression of genes in muscle involved in
oxidative metabolism and delayed motor recovery. GCS inhibition in SOD1(G86R)
mice also affected the expression of metabolic genes and induced a loss of
muscle strength and morphological deterioration of the motor endplates. These
findings suggest that GSLs may play a critical role in ALS muscle pathology and
could lead to the identification of new therapeutic targets. INTRODUCTION: Converging evidence highlights that lipid metabolism plays a key
role in ALS pathophysiology. Dyslipidemia has been described in ALS patients and
may be protective but peripheral lipoprotein subclasses have never been studied.
MATERIAL AND METHODS: We collected sera from 30 ALS patients and 30 gender and
age-matched controls. We analyzed 11 distinct lipoprotein subclasses by linear
polyacrylamide gel electrophoresis (Lipoprint, Quantimetrix Corporation, USA).
We also measured lipoprotein (a), apolipoprotein B, and apolipoprotein E levels.
RESULTS: ALS patients had significant higher total cholesterol, HDL-cholesterol,
and LDL-cholesterol levels than controls (p<0.0001, p=0.0007, and p=0.0065,
respectively). The LDL-1 subfraction concentration was higher (1.03±0.41 vs.
0.71±0.28mmol/L; p=0.0006) and the IDL-B subfraction lower (6.5±2% vs. 8.0±2%;
p=0.001) in ALS patients than controls.
DISCUSSION: Our preliminary work confirmed the association between ALS and
dyslipidemia. The low IDL-B levels may explain the hepatic steatosis frequently
reported in ALS. The high levels of the cholesterol-rich LDL-1 subfraction is
consistent with previously reported hypercholesterolemia.
CONCLUSION: This study describes, for the first time, the distribution of serum
lipoproteins in ALS patients, with low IDL-B and high LDL-1 subfraction level. Lipids are a fundamental class of organic molecules implicated in a wide range
of biological processes related to their structural diversity, and based on this
can be broadly classified into five categories; fatty acids, triacylglycerols
(TAGs), phospholipids, sterol lipids and sphingolipids. Different lipid classes
play major roles in neuronal cell populations; they can be used as energy
substrates, act as building blocks for cellular structural machinery, serve as
bioactive molecules, or a combination of each. In amyotrophic lateral sclerosis
(ALS), dysfunctions in lipid metabolism and function have been identified as
potential drivers of pathogenesis. In particular, aberrant lipid metabolism is
proposed to underlie denervation of neuromuscular junctions, mitochondrial
dysfunction, excitotoxicity, impaired neuronal transport, cytoskeletal defects,
inflammation and reduced neurotransmitter release. Here we review current
knowledge of the roles of lipid metabolism and function in the CNS and discuss
how modulating these pathways may offer novel therapeutic options for treating
ALS. ALS patients exhibit dyslipidemia, hypermetabolism and weight loss; in addition,
cellular energetics deficits have been detected prior to denervation. Although
evidence that metabolism is altered in ALS is compelling, the mechanisms
underlying metabolic dysregulation and the contribution of altered metabolic
pathways to disease remain poorly understood. Here we use a Drosophila model of
ALS based on TDP-43 that recapitulates hallmark features of the disease
including locomotor dysfunction and reduced lifespan. We performed a global,
unbiased metabolomic profiling of larvae expressing TDP-43 (wild-type, TDPWT or
disease-associated mutant, TDPG298S) and identified several lipid metabolism
associated alterations. Among these, we found a significant increase in
carnitine conjugated long-chain fatty acids and a significant decrease in
carnitine, acetyl-carnitine and beta-hydroxybutyrate, a ketone precursor. Taken
together these data suggest a deficit in the function of the carnitine shuttle
and reduced lipid beta oxidation. To test this possibility we used a combined
genetic and dietary approach in Drosophila. Our findings indicate that
components of the carnitine shuttle are misexpressed in the context of TDP-43
proteinopathy and that genetic modulation of CPT1 or CPT2 expression, two core
components of the carnitine shuttle, mitigates TDP-43 dependent locomotor
dysfunction, in a variant dependent manner. In addition, feeding medium-chain
fatty acids or beta-hydroxybutyrate improves locomotor function, consistent with
the notion that bypassing the carnitine shuttle deficit is neuroprotective.
Taken together, our findings highlight the potential contribution of the
carnitine shuttle and lipid beta oxidation in ALS and suggest strategies for
therapeutic intervention based on restoring lipid metabolism in motor neurons. Amyotrophic lateral sclerosis (ALS) is characterized by progressive loss of
upper and lower motor neurons leading to muscle paralysis and death. While a
link between dysregulated lipid metabolism and ALS has been proposed, lipidome
alterations involved in disease progression are still understudied. Using a
rodent model of ALS overexpressing mutant human Cu/Zn-superoxide dismutase gene
(SOD1-G93A), we performed a comparative lipidomic analysis in motor cortex and
spinal cord tissues of SOD1-G93A and WT rats at asymptomatic (~70 days) and
symptomatic stages (~120 days). Interestingly, lipidome alterations in motor
cortex were mostly related to age than ALS. In contrast, drastic changes were
observed in spinal cord of SOD1-G93A 120d group, including decreased levels of
cardiolipin and a 6-fold increase in several cholesteryl esters linked to
polyunsaturated fatty acids. Consistent with previous studies, our findings
suggest abnormal mitochondria in motor neurons and lipid droplets accumulation
in aberrant astrocytes. Although the mechanism leading to cholesteryl esters
accumulation remains to be established, we postulate a hypothetical model based
on neuroprotection of polyunsaturated fatty acids into lipid droplets in
response to increased oxidative stress. Implicated in the pathology of other
neurodegenerative diseases, cholesteryl esters appear as attractive targets for
further investigations. The world's population aging progression renders age-related neurodegenerative
diseases to be one of the biggest unsolved problems of modern society. Despite
the progress in studying the development of pathology, finding ways for
modifying neurodegenerative disorders remains a high priority. One common
feature of neurodegenerative diseases is mitochondrial dysfunction and
overproduction of reactive oxygen species, resulting in oxidative stress.
Although lipid peroxidation is one of the markers for oxidative stress, it also
plays an important role in cell physiology, including activation of
phospholipases and stimulation of signaling cascades. Excessive lipid
peroxidation is a hallmark for most neurodegenerative disorders including
Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and
many other neurological conditions. The products of lipid peroxidation have been
shown to be the trigger for necrotic, apoptotic, and more specifically for
oxidative stress-related, that is, ferroptosis and neuronal cell death. Here we
discuss the involvement of lipid peroxidation in the mechanism of neuronal loss
and some novel therapeutic directions to oppose it. Energy metabolism and redox state are strictly linked; energy metabolism is a
source of reactive oxygen species (ROS) that, in turn, regulate the flux of
metabolic pathways. Moreover, to assure redox homeostasis, metabolic pathways
and antioxidant systems are often coordinately regulated. Several findings show
that superoxide dismutase 1 (SOD1) enzyme has effects that go beyond its
superoxide dismutase activity and that its functions are not limited to the
intracellular compartment. Indeed, SOD1 is secreted through unconventional
secretory pathways, carries out paracrine functions and circulates in the blood
bound to lipoproteins. Striking experimental evidence links SOD1 to the redox
regulation of metabolism. Important clues are provided by the systemic effects
on energy metabolism observed in mutant SOD1-mediated amyotrophic lateral
sclerosis (ALS). The purpose of this review is to analyze in detail the
involvement of SOD1 in redox regulation of metabolism, nutrient sensing,
cholesterol metabolism and regulation of mitochondrial respiration. The
scientific literature on the relationship between ALS, mutated SOD1 and
metabolism will also be explored, in order to highlight the metabolic functions
of SOD1 whose biological role still presents numerous unexplored aspects that
deserve further investigation. Lipids play an important role in the central nervous system (CNS). They
contribute to the structural integrity and physical characteristics of cell and
organelle membranes, act as bioactive signalling molecules, and are utilised as
fuel sources for mitochondrial metabolism. The intricate homeostatic mechanisms
underpinning lipid handling and metabolism across two major CNS cell types;
neurons and astrocytes, are integral for cellular health and maintece. Here,
we explore the various roles of lipids in these two cell types. Given that
changes in lipid metabolism have been identified in a number of
neurodegenerative diseases, we also discuss changes in lipid handling and
utilisation in the context of amyotrophic lateral sclerosis (ALS), in order to
identify key cellular processes affected by the disease, and inform future areas
of research. Author information:
(1)Department of Biostatistics and Health Informatics, King's College London,
London, UK; Maurice Wohl Clinical Neuroscience Institute, King's College London,
Department of Basic and Clinical Neuroscience, London, UK; National Institute
for Health Research Biomedical Research Centre and Dementia Unit at South London
and Maudsley NHS Foundation Trust and King's College London, London, UK.
Electronic address: [email protected].
(2)Institute for Molecular Bioscience, The University of Queensland, Brisbane,
Brisbane QLD 4072, Australia.
(3)Maurice Wohl Clinical Neuroscience Institute, King's College London,
Department of Basic and Clinical Neuroscience, London, UK.
(4)National Institute for Health Research Biomedical Research Centre and
Dementia Unit at South London and Maudsley NHS Foundation Trust and King's
College London, London, UK; Social, Genetic and Developmental Psychiatry Centre,
Institute of Psychiatry, Psychology & Neuroscience, King's College London,
London, UK.
(5)Centre for Motor Neuron Disease Research, Macquarie University, Sidney NSW
2109, Australia.
(6)Centre for Healthy Brain Ageing, School of Psychiatry, UNSW Medicine,
University of New South Wales, Sydney NSW, Australia; Neuroscience Research
Australia, Randwick NSW, Australia.
(7)Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch Perth WA 6150,
Australia; Notre Dame University, 32 Mouat Street, Fremantle WA 6160, Australia;
Murdoch University, 90 South Street, Murdoch WA 6150, Australia.
(8)Calvary Health Care Bethlehem, Parkdale VIC 3195, Australia.
(9)ANZAC Research Institute, Concord Repatriation General Hospital, Sydney NSW
2139, Australia.
(10)Social, Genetic and Developmental Psychiatry Centre, Institute of
Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
(11)Centre for Clinical Research, The University of Queensland, Brisbane QLD,
Australia; Queensland Brain Institute, The University of Queensland, Brisbane
QLD, Australia.
(12)Centre for Clinical Research, The University of Queensland, Brisbane QLD,
Australia; Department of Neurology, Royal Brisbane and Women's Hospital,
Brisbane QLD, Australia.
(13)Brain and Mind Centre, The University of Sydney, Sydney NSW, Australia.
(14)Flinders Medical Centre, Bedford Park SA 5042, Australia.
(15)Centre for Healthy Brain Ageing, School of Psychiatry, UNSW Medicine,
University of New South Wales, Sydney NSW, Australia; Neuropsychiatric
Institute, Prince of Wales Hospital, Sydney NSW Australia.
(16)Department of Biostatistics and Health Informatics, King's College London,
London, UK; National Institute for Health Research Biomedical Research Centre
and Dementia Unit at South London and Maudsley NHS Foundation Trust and King's
College London, London, UK; Institute of Health Informatics, University College
London, London, UK.
(17)Maurice Wohl Clinical Neuroscience Institute, King's College London,
Department of Basic and Clinical Neuroscience, London, UK; Department of
Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano,
Milan, Italy.
(18)Centre for Clinical Research, The University of Queensland, Brisbane QLD,
Australia; Queensland Brain Institute, The University of Queensland, Brisbane
QLD, Australia; Department of Neurology, Royal Brisbane and Women's Hospital,
Brisbane QLD, Australia; Australian Institute for Bioengineering and
Nanotechnology, The University of Queensland, Brisbane QLD, Australia.
(19)Institute for Molecular Bioscience, The University of Queensland, Brisbane,
Brisbane QLD 4072, Australia; Queensland Brain Institute, The University of
Queensland, Brisbane QLD, Australia.
(20)Centre for Clinical Research, The University of Queensland, Brisbane QLD,
Australia; Department of Neurology, Royal Brisbane and Women's Hospital,
Brisbane QLD, Australia; School of Biomedical Sciences, The University of
Queensland, Brisbane QLD, Australia.
(21)Maurice Wohl Clinical Neuroscience Institute, King's College London,
Department of Basic and Clinical Neuroscience, London, UK; King's College
Hospital, Bessemer Road, London SE5 9RS, UK. AIM: Peroxisomes play a key role in lipid metabolism, and peroxisome defects
have been associated with neurodegenerative diseases such as
X-adrenoleukodystrophy and Alzheimer's disease. This study aims to elucidate the
contribution of peroxisomes in lipid alterations of area 8 of the frontal cortex
in the spectrum of TDP43-proteinopathies. Cases of frontotemporal lobar
degeneration-TDP43 (FTLD-TDP), manifested as sporadic (sFTLD-TDP) or linked to
mutations in various genes including expansions of the non-coding region of
C9ORF72 (c9FTLD), and of sporadic amyotrophic lateral sclerosis (sALS) as the
most common TDP43 proteinopathies, were analysed.
METHODS: We used transcriptomics and lipidomics methods to define the
steady-state levels of gene expression and lipid profiles.
RESULTS: Our results show alterations in gene expression of some components of
peroxisomes and related lipid pathways in frontal cortex area 8 in sALS,
sFTLD-TDP and c9FTLD. Additionally, we identify a lipidomic pattern associated
with the ALS-FTLD-TDP43 proteinopathy spectrum, notably characterised by
down-regulation of ether lipids and acylcarnitine among other lipid species, as
well as alterations in the lipidome of each phenotype of TDP43 proteinopathy,
which reveals commonalities and disease-dependent differences in lipid
composition.
CONCLUSION: Globally, lipid alterations in the human frontal cortex of the
ALS-FTLD-TDP43 proteinopathy spectrum, which involve cell membrane composition
and signalling, vulnerability against cellular stress and possible glucose
metabolism, are partly related to peroxisome impairment. The endoplasmic reticulum (ER) and mitochondria connect at multiple contact
sites to form a unique cellular compartment, termed the 'mitochondria-associated
ER membranes' (MAMs). MAMs are hubs for signalling pathways that regulate
cellular homeostasis and survival, metabolism, and sensitivity to apoptosis.
MAMs are therefore involved in vital cellular functions, but they are
dysregulated in several human diseases. Whilst MAM dysfunction is increasingly
implicated in the pathogenesis of neurodegenerative diseases, its role in
amyotrophic lateral sclerosis (ALS) is poorly understood. However, in ALS both
ER and mitochondrial dysfunction are well documented pathophysiological events.
Moreover, alterations to lipid metabolism in neurons regulate processes linked
to neurodegenerative diseases, and a link between dysfunction of lipid
metabolism and ALS has also been proposed. In this review we discuss the
structural and functional relevance of MAMs in ALS and how targeting MAM could
be therapeutically beneficial in this disorder. Nucleocytosolic transport, a membrane process, is impaired in motor neurons in
amyotrophic lateral sclerosis (ALS). This study analyzes the nuclear lipidome in
motor neurons in ALS and examines molecular pathways linked to the major lipid
alterations. Nuclei were obtained from the frozen anterior horn of the lumbar
spinal cord of ALS patients and age-matched controls. Lipidomic profiles of this
subcellular fraction were obtained using liquid chromatography and mass
spectrometry. We validated the mechanisms behind presumable lipidomic changes by
exploring ALS surrogate models including human motor neurons (derived from ALS
lines and controls) subjected to oxidative stress, the hSOD-G93A transgenic
mice, and samples from an independent cohort of ALS patients. Among the
differential lipid species, we noted 41 potential identities, mostly belonging
to phospholipids (particularly ether phospholipids, as plasmalogens), as well as
diacylglycerols and triacylglycerides. Decreased expression of
alkyldihydroxyacetonephosphate synthase (AGPS)-a critical peroxisomal enzyme in
plasmalogen synthesis-is found in motor neuron disease models; this occurs in
parallel with an increase in the expression of sterol carrier protein 2 (SCP2)
mRNA in ALS and Scp2 levels in G93A transgenic mice. Further, we identified
diminished expression of diacylglycerol-related enzymes, such as phospholipase C
βI (PLCβI) and protein kinase CβII (PKCβII), linked to diacylglycerol
metabolism. Finally, lipid droplets were recognized in the nuclei, supporting
the identification of triacylglycerides as differential lipids. Our results
point to the potentially pathogenic role of altered composition of nuclear
membrane lipids and lipids in the nucleoplasm in the anterior horn of the spinal
cord in ALS. Overall, these data support the usefulness of subcellular
lipidomics applied to neurodegenerative diseases. PURPOSE OF REVIEW: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative
disease targeting upper and lower motor neurons, inexorably leading to an early
death. Defects in energy metabolism have been associated with ALS, including
weight loss, increased energy expenditure, decreased body fat mass and increased
use of lipid nutrients at the expense of carbohydrates. We review here recent
findings on impaired energy metabolism in ALS, and its clinical importance.
RECENT FINDINGS: Hypothalamic atrophy, as well as alterations in hypothalamic
peptides controlling energy metabolism, have been associated with metabolic
derangements. Recent studies showed that mutations causing familial ALS impact
various metabolic pathways, in particular mitochondrial function, and lipid and
carbohydrate metabolism, which could underlie these metabolic defects in
patients. Importantly, slowing weight loss, through high caloric diets, is a
promising therapeutic strategy, and early clinical trials indicated that it
might improve survival in at least a subset of patients. More research is needed
to improve these therapeutic strategies, define pharmacological options, and
refine the population of ALS patients that would benefit from these approaches.
SUMMARY: Dysfunctional energy homeostasis is a major feature of ALS clinical
picture and emerges as a potential therapeutic target. Amyotrophic lateral sclerosis (ALS) is a multifactorial and complex fatal
degenerative disorder. A number of pathological mechanisms that lead to motor
neuron death have been identified, although there are many unknowns in the
disease aetiology of ALS. Alterations in lipid metabolism are well documented in
the progression of ALS, both at the systemic level and in the spinal cord of
mouse models and ALS patients. The origin of these lipid alterations remains
unclear. This study aims to identify early lipid metabolic pathways altered
before systemic metabolic symptoms in the spinal cord of mouse models of ALS. To
do this, we performed a transcriptomic analysis of the spinal cord of SOD1G93A
mice at an early disease stage, followed by a robust transcriptomic
meta-analysis using publicly available RNA-seq data from the spinal cord of SOD1
mice at early and late symptomatic disease stages. The meta-analyses identified
few lipid metabolic pathways dysregulated early that were exacerbated at
symptomatic stages; mainly cholesterol biosynthesis, ceramide catabolism, and
eicosanoid synthesis pathways. We present an insight into the pathological
mechanisms in ALS, confirming that lipid metabolic alterations are
transcriptionally dysregulated and are central to ALS aetiology, opening new
options for the treatment of these devastating conditions. BACKGROUND: Premorbid body mass index, physical activity, diabetes and
cardiovascular disease have been associated with an altered risk of developing
amyotrophic lateral sclerosis (ALS). There is evidence of shared genetic risk
between ALS and lipid metabolism. A very large prospective longitudinal
population cohort permits the study of a range of metabolic parameters and the
risk of subsequent diagnosis of ALS.
METHODS: The risk of subsequent ALS diagnosis in those enrolled prospectively to
the UK Biobank (n=502 409) was examined in relation to baseline levels of blood
high and low density lipoprotein (HDL, LDL), total cholesterol, total
cholesterol:HDL ratio, apolipoproteins A1 and B (apoA1, apoB), triglycerides,
glycated haemoglobin A1c (HbA1c) and creatinine, plus self-reported exercise and
body mass index.
RESULTS: Controlling for age and sex, higher HDL (HR 0.84, 95% CI 0.73 to 0.96,
p=0.010) and apoA1 (HR 0.83, 95% CI 0.72 to 0.94, p=0.005) were associated with
a reduced risk of ALS. Higher total cholesterol:HDL was associated with an
increased risk of ALS (HR 1.17, 95% CI 1.05 to 1.31, p=0.006). In models
incorporating multiple metabolic markers, higher LDL or apoB was associated with
an increased risk of ALS, in addition to a lower risk with higher HDL or apoA.
Coronary artery disease, cerebrovascular disease and increasing age were also
associated with an increased risk of ALS.
CONCLUSIONS: The association of HDL, apoA1 and LDL levels with risk of ALS
contributes to an increasing body of evidence that the premorbid metabolic
landscape may play a role in pathogenesis. Understanding the molecular basis for
these changes will inform presymptomatic biomarker development and therapeutic
targeting. Age-associated neurodegenerative diseases such as amyotrophic lateral sclerosis
(ALS), Parkinson's disease (PD) and Alzheimer's disease (AD) are an unmet health
need, with significant economic and societal implications, and an
ever-increasing prevalence. Membrane lipid rafts (MLRs) are specialised plasma
membrane microdomains that provide a platform for intracellular trafficking and
signal transduction, particularly within neurons. Dysregulation of MLRs leads to
disruption of neurotrophic signalling and excessive apoptosis which mirrors the
final common pathway for neuronal death in ALS, PD and AD. Sphingomyelinase
(SMase) and phospholipase (PL) enzymes process components of MLRs and therefore
play central roles in MLR homeostasis and in neurotrophic signalling. We review
the literature linking SMase and PL enzymes to ALS, AD and PD with particular
attention to attractive therapeutic targets, where functional manipulation has
been successful in preclinical studies. We propose that dysfunction of these
enzymes is upstream in the pathogenesis of neurodegenerative diseases and to
support this we provide new evidence that ALS risk genes are enriched with genes
involved in ceramide metabolism (P=0.019, OR = 2.54, Fisher exact test).
Ceramide is a product of SMase action upon sphingomyelin within MLRs, and it
also has a role as a second messenger in intracellular signalling pathways
important for neuronal survival. Genetic risk is necessarily upstream in a late
age of onset disease such as ALS. We propose that manipulation of MLR structure
and function should be a focus of future translational research seeking to
ameliorate neurodegenerative disorders. Author information:
(1)Institute for Cell Engineering, Johns Hopkins University School of Medicine,
Baltimore, MD, USA.
(2)Department of Neurology, Johns Hopkins University School of Medicine,
Baltimore, MD, USA.
(3)The Robert Packard Center, Johns Hopkins University School of Medicine,
Baltimore, MD, USA.
(4)Department of Microbiology and Immunology, Keck School of Medicine,
University of Southern California, Los Angeles, Los Angeles, CA, USA.
(5)Department of Biochemistry, College of Medicine, Dong-A University, Busan,
Korea.
(6)Department of Translational Biomedical Sciences, Graduate School of Dong-A
University, Busan, Korea.
(7)The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University
School of Medicine, Baltimore, MD, USA.
(8)Department of Biology, San Diego State University, San Diego, CA, USA.
(9)Department of Biochemistry and Molecular Biology, Ajou University School of
Medicine, Suwon, Korea.
(10)Institute of Physiological Chemistry, University Medical Center of the
Johannes Gutenberg University Mainz, Mainz, Germany.
(11)School of Life Sciences, Gwangju Institute of Science and Technology,
Gwangju, Republic of Korea.
(12)Jeonbuk Branch Institute, Korea Institute of Toxicology, Jeongeup, Republic
of Korea.
(13)Department of Biomedical Science, Graduate School of Biomedical Science and
Engineering, Hanyang University, Seoul, Republic of Korea.
(14)Cellular and Molecular Medicine Program, School of Medicine, Johns Hopkins
University, Baltimore, MD, USA.
(15)Department of Biochemistry, College of Medicine, Dong-A University, Busan,
Korea. [email protected].
(16)Department of Translational Biomedical Sciences, Graduate School of Dong-A
University, Busan, Korea. [email protected].
(17)Department of Microbiology and Immunology, Keck School of Medicine,
University of Southern California, Los Angeles, Los Angeles, CA, USA.
[email protected].
(18)Institute for Cell Engineering, Johns Hopkins University School of Medicine,
Baltimore, MD, USA. [email protected].
(19)Department of Neurology, Johns Hopkins University School of Medicine,
Baltimore, MD, USA. [email protected].
(20)The Robert Packard Center, Johns Hopkins University School of Medicine,
Baltimore, MD, USA. [email protected].
(21)The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University
School of Medicine, Baltimore, MD, USA. [email protected]. |
What is the multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19? | Multisystem inflammatory syndrome in children (MIS-C) is a well described and documented condition that is associated with the active or recent COVID-19 infection. A similar presentation in adults is termed as Multisystem inflammatory syndrome in Adults (MIS-A). Multisystem inflammatory syndrome in children (MIS-C) is a novel, life-threatening hyperinflammatory condition that develops in children a few weeks after infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This disease has created a diagnostic challenge due to overlap with Kawasaki disease (KD) and KD shock syndrome. The majority of patients with MIS-C present with the involvement of at least four organ systems, and all have evidence of a marked inflammatory state. Most patients show an increase in the level of at least four inflammatory markers (C-reactive protein, neutrophil count, ferritin, procalcitonin, fibrinogen, interleukin-6, and triglycerides). Therapy is primarily with immunomodulators, suggesting that the disease is driven by post-infectious immune dysregulation. Most patients, even those with severe cardiovascular involvement, recover without sequelae. Since coronary aneurysms have been reported, echocardiographic follow-up is needed. | BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C), also known as
pediatric inflammatory multisystem syndrome, is a new dangerous childhood
disease that is temporally associated with coronavirus disease 2019 (COVID-19).
We aimed to describe the typical presentation and outcomes of children diagnosed
with this hyperinflammatory condition.
METHODS: We conducted a systematic review to communicate the clinical signs and
symptoms, laboratory findings, imaging results, and outcomes of individuals with
MIS-C. We searched four medical databases to encompass studies characterizing
MIS-C from January 1st, 2020 to July 25th, 2020. Two independent authors
screened articles, extracted data, and assessed risk of bias. This review was
registered with PROSPERO CRD42020191515.
FINDINGS: Our search yielded 39 observational studies (n = 662 patients). While
71·0% of children (n = 470) were admitted to the intensive care unit, only 11
deaths (1·7%) were reported. Average length of hospital stay was 7·9 ± 0·6 days.
Fever (100%, n = 662), abdominal pain or diarrhea (73·7%, n = 488), and vomiting
(68·3%, n = 452) were the most common clinical presentation. Serum inflammatory,
coagulative, and cardiac markers were considerably abnormal. Mechanical
ventilation and extracorporeal membrane oxygenation were necessary in 22·2%
(n = 147) and 4·4% (n = 29) of patients, respectively. An abnormal
echocardiograph was observed in 314 of 581 individuals (54·0%) with depressed
ejection fraction (45·1%, n = 262 of 581) comprising the most common aberrancy.
INTERPRETATION: Multisystem inflammatory syndrome is a new pediatric disease
associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
that is dangerous and potentially lethal. With prompt recognition and medical
attention, most children will survive but the long-term outcomes from this
condition are presently unknown.
FUNDING: Parker B. Francis and pilot grant from 2R25-HL126140. Funding agencies
had no involvement in the study. OBJECTIVE: Multisystem inflammatory syndrome in children (MIS-C) associated with
coronavirus disease (COVID-19) is a rare and challenging diagnosis requiring
early treatment. The diagnostic criteria involve clinical, laboratory, and
complementary tests. This review aims to draw pediatrician attention to this
diagnosis, suggesting early treatment strategies, and proposing a pediatric
emergency care flowchart.
SOURCES: The PubMed/MEDLINE/WHO COVID-19 databases were reviewed for original
and review articles, systematic reviews, meta-analyses, case series, and
recommendations from medical societies and health organizations published
through July 3, 2020. The reference lists of the selected articles were manually
searched to identify any additional articles.
SUMMARY OF THE FINDINGS: COVID-19 infection is less severe in children than in
adults, but can present as MIS-C, even in patients without comorbidities. There
is evidence of an exacerbated inflammatory response with potential systemic
injury, and it may present with aspects similar to those of Kawasaki disease,
toxic shock syndrome, and macrophage activation syndrome. MIS-C can develop
weeks after COVID-19 infection, suggesting an immunomediated cause. The most
frequent clinical manifestations include fever, gastrointestinal symptoms, rash,
mucous membrane changes, and cardiac dysfunction. Elevated inflammatory markers,
lymphopenia, and coagulopathy are common laboratory findings. Supportive
treatment and early immunomodulation can control the intense inflammatory
response and reduce complications and mortality.
CONCLUSIONS: MIS-C associated with COVID-19 is serious, rare, and potentially
fatal. The emergency department pediatrician must recognize and treat it early
using immunomodulatory strategies to reduce systemic injury. Further studies are
needed to identify the disease pathogenesis and establish the most appropriate
treatment. Author information:
(1)Science for Life Laboratory, Department of Women's and Children Health,
Karolinska Institutet, Stockholm 17165, Sweden.
(2)Research Unit of Congenital and Perinatal Infections, Bambino Gesù Children's
Hospital, Rome 00165, Italy; Chair of Pediatrics, Department of Systems
Medicine, University of Rome "Tor Vergata", Rome 00133, Italy.
(3)Department of Medicine (Solna), Karolinska University Hospital, Karolinska
Institutet, Stockholm 17176, Sweden.
(4)Research Unit of Congenital and Perinatal Infections, Bambino Gesù Children's
Hospital, Rome 00165, Italy.
(5)Research Unit of Congenital and Perinatal Infections, Bambino Gesù Children's
Hospital, Rome 00165, Italy; Academic Department of Pediatrics, Bambino Gesù
Children's Hospital, IRCCS, Rome 00165, Italy.
(6)Center for Regenerative Medicine, Department of Medicine, Karolinska
Institutet, Stockholm 14186, Sweden.
(7)Department of Medicine (Solna), Karolinska University Hospital, Karolinska
Institutet, Stockholm 17176, Sweden; Department of Immunology, Genetics and
Pathology, Uppsala University and Department of Clinical Genetics, Uppsala
University Hospital, Uppsala 75185, Sweden.
(8)Academic Department of Pediatrics, Bambino Gesù Children's Hospital, IRCCS,
Rome 00165, Italy.
(9)Chair of Pediatrics, Department of Systems Medicine, University of Rome "Tor
Vergata", Rome 00133, Italy; Academic Department of Pediatrics, Bambino Gesù
Children's Hospital, IRCCS, Rome 00165, Italy.
(10)Department of Medicine (Solna), Karolinska University Hospital, Karolinska
Institutet, Stockholm 17176, Sweden; Science for life Laboratory, Department of
Medical Sciences, Uppsala University, Uppsala 75237, Sweden. Electronic address:
[email protected].
(11)Research Unit of Congenital and Perinatal Infections, Bambino Gesù
Children's Hospital, Rome 00165, Italy; Chair of Pediatrics, Department of
Systems Medicine, University of Rome "Tor Vergata", Rome 00133, Italy.
Electronic address: [email protected].
(12)Science for Life Laboratory, Department of Women's and Children Health,
Karolinska Institutet, Stockholm 17165, Sweden; Pediatric Rheumatology,
Karolinska University Hospital, Stockholm 17164, Sweden. Electronic address:
[email protected]. AIM: This study determined the influence of the COVID-19 pandemic on the
occurrence of multisystem inflammatory syndrome in children (MIS-C) and compared
the main characteristics of MIS-C and Kawasaki disease (KD).
METHODS: We included patients aged up to 18 years of age who were diagnosed with
MIS-C or KD in a paediatric university hospital in Paris from 1 January 2018 to
15 July 2020. Clinical, laboratory and imaging characteristics were compared,
and new French COVID-19 cases were correlated with MIS-C cases in our hospital.
RESULTS: There were seven children with MIS-C, from 6 months to 12 years of age,
who were all positive for the virus that causes COVID-19, and 40 virus-negative
children with KD. Their respective characteristics were as follows: under
5 years of age (14.3% vs. 85.0%), paediatric intensive care unit admission (100%
vs. 10.0%), abdominal pain (71.4% vs. 12.5%), myocardial dysfunction (85.7% vs.
5.0%), shock syndrome (85.7% vs. 2.5%) and mean and standard deviation
C-reactive protein (339 ± 131 vs. 153 ± 87). There was a strong lagged
correlation between the rise and fall in MIS-C patients and COVID-19 cases.
CONCLUSION: The rise and fall of COVID-19 first wave mirrored the MIS-C cases.
There were important differences between MIS-C and KD. The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2) infection has been spreading worldwide since
December 2019. Hundreds of cases of children and adolescents with Kawasaki
disease (KD)-like hyperinflammatory illness have been reported in Europe and the
United States during the peak of the COVID-19 pandemic with or without shock and
cardiac dysfunction. These patients tested positive for the polymerase chain
reaction or antibody test for SARS-CoV-2 or had a history of recent exposure to
COVID-19. Clinicians managing such patients coined new terms for this new
illness, such as COVID-19-associated hyperinflammatory response syndrome,
pediatric inflammatory multisystem syndrome temporally associated with COVID-19,
or COVID-19-associated multisystem inflammatory syndrome in children (MIS-C).
The pathogenesis of MIS-C is unclear; however, it appears similar to that of
cytokine storm syndrome. MIS-C shows clinical features similar to KD, but
differences between them exist with respect to age, sex, and racial
distributions and proportions of patients with shock or cardiac dysfunction.
Recommended treatments for MIS-C include intravenous immunoglobulin,
corticosteroids, and inotropic or vasopressor support. For refractory patients,
monoclonal antibody to interleukin-6 receptor (tocilizumab), interleukin-1
receptor antagonist (anakinra), or monoclonal antibody to tumor necrosis factor
(infliximab) may be recommended. Patients with coronary aneurysms require
aspirin or anticoagulant therapy. The prognosis of MIS-C seemed favorable
without sequelae in most patients despite a reported mortality rate of
approximately 1.5%. The prevalence of multisystem inflammatory syndrome in children (MIS-C) has
increased since the coronavirus disease 2019 (COVID-19) pandemic started. This
study was aimed to describe clinical manifestation and outcomes of MIS-C
associated with COVID-19. This systematic review and meta-analysis were
conducted on all available literature until July 3rd, 2020. The screening was
done by using the following keywords: ("novel coronavirus" Or COVID-19 or severe
acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or coronavirus) and
("MIS-C" or "multisystem inflammatory" or Kawasaki). Data on gender, ethnicity,
clinical presentations, need for mechanical ventilation or admission to
intensive care unit (ICU), imaging, cardiac complications, and COVID-19
laboratory results were extracted to measure the pooled estimates. Out of 314
found articles, 16 articles with a total of 600 patients were included in the
study, the most common presentation was fever (97%), followed by
gastrointestinal symptoms (80%), and skin rashes (60%) as well as shock (55%),
conjunctivitis (54%), and respiratory symptoms (39%). Less common presentations
were neurologic problems (33%), and skin desquamation (30%), MIS-C was slightly
more prevalent in males (53.7%) compared to females (46.3%). The findings of
this meta-analysis on current evidence found that the common clinical
presentations of COVID-19 associated MIS-C include a combination of fever and
mucocutaneous involvements, similar to atypical Kawasaki disease, and multiple
organ dysfunction. Due to the relatively higher morbidity and mortality rate, it
is very important to diagnose this condition promptly. The coronavirus disease 2019 (COVID-19) pandemic has caused widespread mortality
and morbidity. Though children are largely spared from severe illness, a novel
childhood hyperinflammatory syndrome presumed to be associated with and
subsequent to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
infection has emerged with potentially severe outcomes. Multisystem inflammatory
disorder in children (MIS-C) most commonly affects young, school-aged children
and is characterized by persistent fever, systemic hyperinflammation, and
multisystem organ dysfunction. While uncommon and generally treatable, MIS-C
presents potentially life-altering medical sequelae, complicated by a dearth of
information regarding its etiology, pathophysiology, and long-term outcomes. The
severity of MIS-C may warrant the need for increased awareness and continued
COVID-19 mitigation efforts, particularly until potential factors conferring a
predisposition to MIS-C can be clarified through additional research.
Well-informed guidelines will be critical as the school year progresses. In this
article, current knowledge on MIS-C is reviewed and the potential implications
of this novel syndrome are discussed from a public health perspective. BACKGROUND: SARS-CoV-2 occurs in the majority of children as COVID-19, without
symptoms or with a paucisymptomatic respiratory syndrome, but a small proportion
of children develop the systemic Multi Inflammatory Syndrome (MIS-C),
characterized by persistent fever and systemic hyperinflammation, with some
clinical features resembling Kawasaki Disease (KD).
OBJECTIVE: With this study we aimed to shed new light on the pathogenesis of
these two SARS-CoV-2-related clinical manifestations.
METHODS: We investigated lymphocyte and dendritic cells subsets,
chemokine/cytokine profiles and evaluated the neutrophil activity mediators,
myeloperoxidase (MPO), and reactive oxygen species (ROS), in 10 children with
COVID-19 and 9 with MIS-C at the time of hospital admission.
RESULTS: Patients with MIS-C showed higher plasma levels of C reactive protein
(CRP), MPO, IL-6, and of the pro-inflammatory chemokines CXCL8 and CCL2 than
COVID-19 children. In addition, they displayed higher levels of the chemokines
CXCL9 and CXCL10, mainly induced by IFN-γ. By contrast, we detected IFN-α in
plasma of children with COVID-19, but not in patients with MIS-C. This
observation was consistent with the increase of ISG15 and IFIT1 mRNAs in cells
of COVID-19 patients, while ISG15 and IFIT1 mRNA were detected in MIS-C at
levels comparable to healthy controls. Moreover, quantification of the number of
plasmacytoid dendritic cells (pDCs), which constitute the main source of IFN-α,
showed profound depletion of this subset in MIS-C, but not in COVID-19.
CONCLUSIONS: Our results show a pattern of immune response which is suggestive
of type I interferon activation in COVID-19 children, probably related to a
recent interaction with the virus, while in MIS-C the immune response is
characterized by elevation of the inflammatory cytokines/chemokines IL-6, CCL2,
and CXCL8 and of the chemokines CXCL9 and CXL10, which are markers of an active
Th1 type immune response. We believe that these immunological events, together
with neutrophil activation, might be crucial in inducing the multisystem and
cardiovascular damage observed in MIS-C. The coronavirus disease 2019 (COVID-19) pandemic has impacted the health of
children worldwide. Although overall mortality from COVID-19 in children remains
low, an associated multisystem inflammatory disorder has emerged. The disorder
has been recognized and named multisystem inflammatory syndrome in children
(MIS-C) by the World Health Organization and the Centers for Disease Control and
Prevention. This comprehensive review describes the epidemiology,
pathophysiology, signs and symptoms, other potential diagnoses, and treatments
relevant to MIS-C. The review also includes patient and family education and
anticipatory guidance, and discusses nursing implications for nurses working in
various roles and settings, including direct care, research, and public health. Most of the reports about severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2) in children reported mild-to-moderate disease manifestations.
However, recent reports explored a rare pediatric multisystem syndrome possibly
associated with SARS-CoV-2 infection termed multisystem inflammatory syndrome in
children (MIS-C).The study prospectively enrolled 5 patients with clinical and
laboratory evidence of MIS-C associated with SARS-CoV-2 infection. They were
admitted to the pediatric intensive care unit (PICU). Their clinical
presentation, laboratory, and outcome were described.All patients shared similar
clinical presentations such as persistent documented fever for more than 3 days,
respiratory symptoms, gastrointestinal involvement, and increased inflammatory
markers (CRP, ESR, and ferritin). Three patients had concurrent positive
coronavirus disease 2019 (COVID-19) infection, and the other 2 patients had
contact with suspected COVID-19 positive patients. They were all managed in the
PICU and received intravenous immunoglobulin, systemic steroid, and
hydroxychloroquine. The hospital stays ranged between 3 and 21 days. One patient
died due to severe multiorgan failures and shock, and the other 4 patients were
discharged with good conditions.Pediatric patients with SARS-CoV-2 are at risk
for MIS-C. MIS-C has a spectrum of clinical and laboratory presentations, and
the clinicians need to have a high index of suspicion for the diagnosis and
should initiate its early treatment to avoid unfavorable outcomes. Long-term
follow-up studies will be required to explore any sequelae of MIS-C, precisely
the cardiovascular complications. OBJECTIVE: Although the initial reports of COVID-19 cases in children described
that children were largely protected from severe manifestations, clusters of
paediatric cases of severe systemic hyperinflammation and shock related to
severe acute respiratory syndrome coronavirus 2 infection began to be reported
in the latter half of April 2020. A novel syndrome called "multisystem
inflammatory syndrome in children" (MIS-C) shares common clinical features with
other well-defined syndromes, including Kawasaki disease, toxic shock syndrome
and secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome.
Our objective was to develop a protocol for the evaluation, treatment and
follow-up of patients with MIS-C.
METHODS: The protocol was developed by a multidisciplinary team. We convened a
multidisciplinary working group with representation from the departments of
paediatric critical care, cardiology, rheumatology, surgery, gastroenterology,
haematology, immunology, infectious disease and neurology. Our protocol and
recommendations were based on the literature and our experiences with
multisystem inflammatory syndrome in children. After an agreement was reached
and the protocol was implemented, revisions were made on the basis of expert
feedback.
CONCLUSION: Children may experience acute cardiac decompensation or other organ
system failure due to this severe inflammatory condition. Therefore, patients
with severe symptoms of MIS-C should be managed in a paediatric intensive care
setting, as rapid clinical deterioration may occur. Therapeutic approaches for
MIS-C should be tailored depending on the patients' phenotypes. Plasmapheresis
may be useful as a standard treatment to control hypercytokinemia in cases of
MIS-C with severe symptoms. Long-term follow-up of patients with cardiac
involvement is required to identify any sequelae of MIS-C. BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a dangerous
pediatric complication of COVID-19.
OBJECTIVE: The purpose of this review article is to provide a summary of the
diagnosis and management of MIS-C with a focus on management in the acute care
setting.
DISCUSSION: MIS-C is an inflammatory syndrome which can affect nearly any organ
system. The most common symptoms are fever and gastrointestinal symptoms, though
neurologic and dermatologic findings are also well-described. The diagnosis
includes a combination of clinical and laboratory testing. Patients with MIS-C
will often have elevated inflammatory markers and may have an abnormal
electrocardiogram or echocardiogram. Initial treatment involves resuscitation
with careful assessment for cardiac versus vasodilatory shock using
point-of-care ultrasound. Treatment should include intravenous immunoglobulin,
anticoagulation, and consideration of corticosteroids. Interleukin-1 and/or
interleukin-6 blockade may be considered for refractory cases. Aspirin is
recommended if there is thrombocytosis or Kawasaki disease-like features on
echocardiogram. Patients will generally require admission to an intensive care
unit.
CONCLUSION: MIS-C is a condition associated with morbidity and mortality that is
increasingly recognized as a potential complication in pediatric patients with
COVID-19. It is important for emergency clinicians to know how to diagnose and
treat this disorder. El síndrome inflamatorio multisistémico pediátrico vinculado a la COVID-19
(SIM-PedS) es, según la Organización Mundial de la Salud, un nuevo síndrome
descrito en pacientes menores de 19 años con historia previa de exposición a
SARS-CoV-2. La presentación inicial de este síndrome se caracteriza por fiebre
persistente que asocia debilidad, dolor abdominal, vómitos y/o diarrea. Menos
frecuentemente los pacientes pueden presentar también erupción cutánea y
conjuntivitis. El cuadro clínico tiene expresividad y evolución variables, por
lo que algunos pacientes pediátricos afectados pueden empeorar rápidamente,
desarrollando desde hipotensión y shock cardiogénico a daño multiorgánico. Los
hallazgos analíticos característicos del síndrome consisten en elevación de
marcadores inflamatorios y disfunción cardíaca. Los hallazgos radiológicos más
frecuentes son cardiomegalia, derrame pleural, signos de insuficiencia cardíaca,
ascitis y cambios inflamatorios en la fosa ilíaca derecha. En la pandemia actual
por COVID-19 es necesario que el radiólogo conozca las características
clínico-analíticas y radiológicas de este síndrome para realizar un correcto
diagnóstico. The varied spectrum of presentation of the severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) is intriguing. Multisystem inflammatory syndrome in
children (MIS-C) is a well described and documented condition that is associated
with the active or recent COVID-19 infection. A similar presentation in adults
is termed as Multisystem inflammatory syndrome in Adults (MIS-A). With only very
limited cases reported from the west, MIS-A is considered a rare and serious
complication of COVID-19. However, it is not as uncommon as we think. Many cases
go undiagnosed for lack of COVID -19 like symptoms and unawareness among
treating clinicians about this newer clinical entity. Further, antibody testing
and inflammatory markers are not easily available in many of the Indian
hospitals especially in rural India where the second wave had been intense,
thereby making it difficult for the diagnosis of MIS-A. Also, there is no clear
treatment guideline for MIS-A unlike MIS-C where the treatment protocol is well
laid out. Awareness about MIS-A among treating clinicians can thus help in
further evaluation and increased identification of the syndrome at the early
stages thereby helping in the early institution of treatment. Our tertiary COVID
care hospital in South India which has handled about 5200 cases of COVID-19 is
been able to identify 04 cases of MIS-A proving that this clinical entity is not
as rare as it is thought but lacks reporting and prompt identification. Here we
describe 04 cases of MIS-A and strive to bring in the various aspects of it,
including the clinical presentation, laboratory markers, diagnostic criteria and
treatment considerations in this post second wave of the COVID-19 pandemic in
India. Multisystem inflammatory syndrome in children (MIS-C) is a novel,
life-threatening hyperinflammatory condition that develops in children a few
weeks after infection with severe acute respiratory syndrome coronavirus-2
(SARS-CoV-2). This disease has created a diagnostic challenge due to overlap
with Kawasaki disease (KD) and KD shock syndrome. The majority of patients with
MIS-C present with the involvement of at least four organ systems, and all have
evidence of a marked inflammatory state. Most patients show an increase in the
level of at least four inflammatory markers (C-reactive protein, neutrophil
count, ferritin, procalcitonin, fibrinogen, interleukin-6, and triglycerides).
Therapy is primarily with immunomodulators, suggesting that the disease is
driven by post-infectious immune dysregulation. Most patients, even those with
severe cardiovascular involvement, recover without sequelae. Since coronary
aneurysms have been reported, echocardiographic follow-up is needed.Further
study is needed to create uniform diagnostic criteria, therapy, and follow-up
protocols. Myocardial infarctions (MI) have been reported in adults with COVID-19. Although
MIs are rare in children with COVID-19, cardiac involvement is still possible.
In this case report, we present an adolescent with recent COVID-19 infection who
presented with an ECG initially suggestive of myocardial infarction (MI). We
describe how to differentiate between myocardial infarctions and
myopericarditis. A 15-year-old boy, with a history of COVID-19 infection a month
prior, presented to the emergency department with fever, abdominal pain,
diarrhea, and chest pain. On ECG, he was found to have focal ST-segment
elevations in V3 through V6. Given the immediate concern for MI, an emergent
echocardiogram was done and showed normal left ventricular systolic function
with no regional dyskinesia and normal coronary artery diameters. A repeat ECG
showed diffuse ST elevations in the inferior leads and T-wave inversions on V5
and V6, confirming the diagnosis of myopericarditis. In conclusion,
multisystem-inflammatory syndrome in children associated with COVID-19 (MIS-C)
is a new entity describing a post-infectious inflammatory response in children
with prior COVID-19 exposure. Cardiac involvement can include myopericarditis.
Initial ECGs may show ST-changes suggestive of MI. However, serial ECGs and
echocardiograms can differentiate between MI and myocarditis/myopericarditis.
Even with COVID-19, MIs are extremely rare in children, and it is important to
be aware of MIS-C and its cardiac complications. OBJECTIVE: To differentiate severe/critical coronavirus disease 2019 (COVID-19)
infection from multisystem inflammatory syndrome in children (MIS-C).
METHODS: Single-center chart review comparing characteristics of children with
MIS-C and 'severe/critical' COVID-19 infection. Multivariate logistic regression
was performed to create predictive models for predicting MIS-C.
RESULTS: Of 68 patients, 28 (41.2%) had MIS-C while 40 (58.8%) had
severe/critical COVID-19 infection. MIS-C patients had a higher prevalence of
fever, mucocutaneous, cardiac and gastrointestinal involvement and a lower
prevalence of respiratory symptoms (P<0.05). Significantly lower hemoglobin,
platelet count, serum electrolytes, and significantly elevated inflammatory and
coagulation markers were observed in MIS-C cohort. Upon multivariate logistic
regression, the best model included C-reactive protein (CRP), platelet count,
gastrointestinal and mucocutaneus involvement and absence of respiratory
involvement (performance of 0.94). CRP>40 mg/L with either platelet count
<150x109 or mucocutaneous involvement had specificity of 97.5% to diagnose
MIS-C.
CONCLUSION: Elevated CRP, thrombocytopenia and mucocutaneous involvement at
presentation are helpful in differentiating MIS-C from severe COVID-19. BACKGROUND: : Multisystem inflammatory syndrome in children (MIS-C) associated
with coronavirus disease 2019 (COVID-19) is an emerging condition that was first
identified in paediatrics at the onset of the COVID-19 pandemic. The condition
is also known as pediatric inflammatory multisystem syndrome temporally
associated with severe acute respiratory syndrome coronavirus 2 (PIMS-TS or
PIMS), and multiple definitions have been established for this condition that
share overlapping features with Kawasaki Disease and toxic shock syndrome.
METHODS: : A review was conducted to identify literature describing the
epidemiology of MIS-C, published up until March 9, 2021. A database established
at the Public Health Agency of Canada with COVID-19 literature was searched for
articles referencing MIS-C, PIMS or Kawasaki Disease in relation to COVID-19.
RESULTS: : A total of 195 out of 988 articles were included in the review. The
median age of MIS-C patients was between seven and 10 years of age, although
children of all ages (and adults) can be affected. Multisystem inflammatory
syndrome in children disproportionately affected males (58% patients), and Black
and Hispanic children seem to be at an elevated risk for developing MIS-C.
Roughly 62% of MIS-C patients required admission to an intensive care unit, with
one in five patients requiring mechanical ventilation. Between 0% and 2% of
MIS-C patients died, depending on the population and available interventions.
CONCLUSION: : Multisystem inflammatory syndrome in children can affect children
of all ages. A significant proportion of patients required intensive care unit
and mechanical ventilation and 0%-2% of cases resulted in fatalities. More
evidence is needed on the role of race, ethnicity and comorbidities in the
development of MIS-C. Multisystem inflammatory syndrome in children (MIS-C) is a rare and critical
condition that affects children following exposure to severe acute respiratory
syndrome Coronavirus 2 (SARS-CoV-2) infection, leading to multiorgan dysfunction
and shock. MIS-C has been reported from different parts of the world but rarely
from Arab countries. In this report, we describe a 15-year-old Arab boy who was
admitted to the ICU during the surge of Coronavirus transmission in Syria with a
clinical picture consistent with MIS-C, including high-grade fever,
gastrointestinal symptoms, rash, multiorgan dysfunction, and shock. Laboratory
profile showed significant elevation of inflammatory markers, negative
SARS-CoV-2 RT-PCR testing but positive serologic testing for SARS-CoV-2. The
patient received intravenous immunoglobulins (IVIG) and glucocorticoids with
remarkable cardiac improvement and significant alleviation in inflammatory
markers. To our knowledge, this is the first reported case of MIS-C from Syria,
which adds to the epidemiological data about this new syndrome. |
What datasets are available related to Duchenne Muscular Dystrophy? | Using data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) Five sources of RWD/NHD were contributed by Universitaire Ziekenhuizen Leuven, DMD Italian Group, The Cooperative International Neuromuscular Research Group, ImagingDMD, and the PRO-DMD-01 study (n = 430 patients, in total). | PURPOSE: To determine whether sociodemographic factors are associated with
delays at specific steps in the diagnostic process of Duchenne and Becker
muscular dystrophy.
METHODS: We examined abstracted medical records for 540 males from
population-based surveillance sites in Arizona, Colorado, Georgia, Iowa, and
western New York. We used linear regressions to model the association of three
sociodemographic characteristics with age at initial medical evaluation, first
creatine kinase measurement, and earliest DNA analysis while controlling for
changes in the diagnostic process over time. The analytical dataset included 375
males with information on family history of Duchenne and Becker muscular
dystrophy, neighborhood poverty levels, and race/ethnicity.
RESULTS: Black and Hispanic race/ethnicity predicted older ages at initial
evaluation, creatine kinase measurement, and DNA testing (P < 0.05). A positive
family history of Duchenne and Becker muscular dystrophy predicted younger ages
at initial evaluation, creatine kinase measurement and DNA testing (P < 0.001).
Higher neighborhood poverty was associated with earlier ages of evaluation (P <
0.05).
CONCLUSIONS: Racial and ethnic disparities in the diagnostic process for
Duchenne and Becker muscular dystrophy are evident even after adjustment for
family history of Duchenne and Becker muscular dystrophy and changes in the
diagnostic process over time. Black and Hispanic children are initially
evaluated at older ages than white children, and the gap widens at later steps
in the diagnostic process. OBJECTIVE: To review current approaches for obtaining patient data in Duchenne
muscular dystrophy (DMD) and consider how monitoring and comparing outcome
measures across DMD clinics could facilitate standardized and improved patient
care.
METHODS: We reviewed annual standardized data from cystic fibrosis (CF) clinics
and DMD care guidelines and consensus statements; compared current approaches to
obtain DMD patient data and outcome measures; and considered the best method for
implementing public reporting of outcomes, to drive improvements in health care
delivery.
RESULTS: Current methods to monitor DMD patient information (MD STARnet,
DuchenneConnect, and TREAT-NMD) do not yet provide patients with comparative
outcome data. The CF patient registry allows for reporting of standard outcomes
across clinics and is associated with improved CF outcomes. A similar patient
registry is under development for the Muscular Dystrophy Association (MDA)
clinic network. Suggested metrics for quality care include molecular diagnosis,
ambulatory status and age at loss of ambulation, age requiring ventilator
support, and survival.
CONCLUSIONS: CF longevity has increased by almost 33% from 1986 to 2010, in part
due to a CF patient registry that has been stratified by individual care centers
since 1999, and publically available since 2006. Implementation of outcome
reporting for MDA clinics might promote a similar benefit to patients with DMD. BACKGROUND: Gene expression analysis is powerful for investigating the
underlying mechanisms of Duchenne muscular dystrophy (DMD). Previous studies
mainly neglected co-expression or transcription factor (TF) information. Here we
integrated TF information into differential co-expression analysis (DCEA) to
explore new understandings of DMD pathogenesis.
METHODS: Using two microarray datasets from Gene Expression Omnibus (GEO)
database, we firstly detected differentially expressed genes (DEGs) and pathways
enriched with DEGs. Secondly, we constructed differentially regulated networks
to integrate the TF-to-target information and the differential co-expression
genes.
RESULTS: A total of 454 DEGs were detected and both KEGG pathway and ingenuity
pathway analysis revealed that pathways enriched with aberrantly regulated genes
are mostly involved in the immune response processes. DCEA results generated 610
pairs of DEGs regulated by at least one common TF, including 78 pairs of
co-expressed DEGs. A network was constructed to illustrate their relationships
and a subnetwork for DMD related molecules was constructed to show genes and TFs
that may play important roles in the secondary changes of DMD. Among the DEGs
which shared TFs with DMD, six genes were co-expressed with DMD, including
ATP1A2, C1QB, MYOF, SAT1, TRIP10, and IFI6.
CONCLUSION: Our results may provide a new understanding of DMD and contribute
potential targets for future therapeutic tests.
VIRTUAL SLIDES: The virtual slide(s) for this article can be found here:
http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_210. PURPOSE OF REVIEW: This review aims to describe the benefits and limitations of
using the Duchenne Connect patient registry to provide information particularly
in regard to active treatment choices in Duchenne muscular dystrophy and their
impact on disease progression.
RECENT FINDINGS: Clinical trials and natural history studies are difficult for
rare diseases like Duchenne muscular dystrophy. Using an online patient
self-report survey model, Duchenne Connect provides relevant data that are
difficult to gather in other ways. Validation of the overall dataset is
supported by comparable mutational spectrum relative to other cohorts and
demonstrated beneficial effect of corticosteroid use in prolonging ambulation.
These types of analyses are provocative and allow multivariate analyses across
the breadth of patient and physician medication and supplement practices.
Because the data are self-reported and online, the barrier to participation is
low and great potential exists for novel directions of further research in a
highly participatory forum.
SUMMARY: Patient registries for Duchenne and Becker muscular dystrophy (DBMD)
are powerful tools for monitoring patient outcomes, comparing treatment options,
and relating information between patients, researchers, and clinicians. Duchenne
Connect is an online patient self-report registry for individuals with DBMD that
facilitates aggregation of treatment modalities, outcomes, and genotype data and
has played a vital role in furthering DBMD research, particularly in the USA, in
a highly participatory and low-cost manner. Individuals with Duchenne muscular dystrophy (DMD) often exhibit delayed motor
and cognitive development, including delayed onset of ambulation. Data on age
when loss of independent ambulation occurs are well established for DMD;
however, age at onset of walking has not been well described. We hypothesize
that an effective medication given in early infancy would advance the age when
walking is achieved so that it is closer to age-matched norms, and that this
discrete event could serve as the primary outcome measure in a clinical trial.
This study examined three data sets, Muscular Dystrophy Surveillance, Tracking,
and Research Network (MD STARnet); Dutch Natural History Survey (DNHS); and
Parent Project Muscular Dystrophy (PPMD). The distribution of onset of
ambulation in DMD (mean ± SD) and median age, in months, at the onset of
ambulation was 17.3 (±5.5) and 16.0 in MD STARnet, 21.8 (±7.1) and 20.0 in DNHS,
and 16.1 (±4.4) and 15 in PPMD. Age of ambulation in these data sets were all
significantly later (P <0.001) than the corresponding age for typically
developing boys, 12.1 (±1.8). A hypothetical clinical trial study design and
power analyses are presented based on these data. BACKGROUND: Duchenne muscular dystrophy (DMD) is the most common disease in
children caused by mutations in the DMD gene, and DMD and Becker muscular
dystrophy (BMD) are collectively called dystrophinopathies. Dystrophinopathies
show a complex mutation spectrum. The importance of mutation databases, with
clinical phenotypes and protein studies of patients, is increasingly recognized
as a reference for genetic diagnosis and for the development of gene therapy.
METHODS: We used the data from the Japanese Registry of Muscular Dystrophy
(Remudy) compiled during from July 2009 to March 2017, and reviewed 1497
patients with dystrophinopathies.
RESULTS: The spectrum of identified mutations contained exon deletions (61%),
exon duplications (13%), nonsense mutations (13%), small deletions (5%), small
insertions (3%), splice-site mutations (4%), and missense mutations (1%). Exon
deletions were found most frequently in the central hot spot region between
exons 45-52 (42%), and most duplications were detected in the proximal hot spot
region between exons 3-25 (47%). In the 371 patients harboring a small mutation,
194 mutations were reported and 187 mutations were unreported.
CONCLUSIONS: We report the largest dystrophinopathies mutation dataset in Japan
from a national patient registry, "Remudy". This dataset provides a useful
reference to support the genetic diagnosis and treatment of dystrophinopathy. A retrospective study in which we reviewed the hospital files of a subset of 7
patients with Duchenne muscular dystrophy participating in the open-label phase
I/II PRO051-02 study in Leuven. The objective of this study was to describe in
detail the injection site reactions in these children treated with drisapersen
(PRO-051), a 2'-O-methyl phosphorothioate RNA antisense oligonucleotide, that
induces exon 51 skipping in Duchenne muscular dystrophy. Antisense
oligonucleotides, restoring the reading frame by skipping of exons, have become
a potential treatment of Duchenne muscular dystrophy and other monogenetic
diseases. Erythema followed by hyperpigmentation, fibrosis, and calcification
were seen at the injection sites in all children. Ulcerations, which were
difficult to heal, occurred in 5 of 7 children. Progression still occurred after
switching to intravenous administration of drisapersen or even after stopping
therapy. Systemic reactions included a reversible proteinuria and
α1-microglobulinuria. Moreover, hypotrichosis was a common feature.Conclusion:
Subcutaneous administration of drisapersen causes severe and progressive
injection site effects. What is known: • Antisense oligonucleotides offer the
possibility to convert Duchenne muscular dystrophy to the less severe Becker
type. This can potentially be achieved by targeting and skipping specific exons
of the Duchenne muscular dystrophy gene to restore the disrupted reading frame
and to induce the production of a semi functional dystrophin protein. •
Drisapersen is such an antisense oligonucleotides which can be administered
subcutaneously. Its use has been tested extensively in the escalating dose pilot
study (PRO051-02). What is new: • This report describes the injection site
reactions caused by this type of agent in detail which has never been done
before. We therefore reviewed the hospital files of 7 patients with Duchenne
muscular dystrophy participating in the phase I/II open-label, escalating dose
pilot study (PRO051-02) with drisapersen. • Severe side effects starting with
erythema, hyperpigmentation, and later fibrosis, calcification, and difficult to
treat ulcerations developed in all patients, and these continued to progress
even after cessation of drisapersen. We discuss some possible underlying
mechanisms. The exact mechanism however is still not known. AIM: To investigate the differences in attainment of developmental milestones
between young males with Duchenne muscular dystrophy (DMD) and young males from
the general population.
METHOD: As part of the case-control 4D-DMD study (Detection by Developmental
Delay in Dutch boys with Duchenne Muscular Dystrophy), data on developmental
milestones for 76 young males with DMD and 12 414 young males from a control
group were extracted from the health care records of youth health care services.
The characteristics of DMD were acquired from questionnaires completed by
parents. Logistic regression analyses were performed with milestone attainment
(yes/no) as the dependent variable and DMD (yes/no) as the independent variable,
with and without adjustment for age at visit.
RESULTS: The mean number of available milestones was 43 (standard deviation
[SD]=13, range: 1-59) in the DMD group and 40 (SD=15, range: 1-60) in the
control group. The presence of developmental delay was evident at 2 to 3 months
of age, with a higher proportion of young males with DMD failing to attain
milestones of gross/fine motor activity, adaptive behaviour, personal/social
behaviour, and communication (range age-adjusted odds ratios [ORs]=2.3-4.0,
p<0.01). Between 12 and 36 months of age, differences in the attainment of
developmental milestones concerning gross motor activity increased with age
(range age-adjusted ORs=10.3-532, p<0.001). We also found differences in
developmental milestones concerning fine motor activity, adaptive behaviour,
personal/social behaviour, and communication between 12 and 48 months of age
(range age-adjusted ORs=2.5-9.7, p<0.01).
INTERPRETATION: We found delays in the attainment of motor and non-motor
milestones in young males with DMD compared to the control group. Such delays
were already evident a few months after birth. Developmental milestones that
show a delay in attainment have the potential to aid the earlier diagnosis of
DMD. PURPOSE: Duchenne muscular dystrophy (DMD) is currently the most commonly
diagnosed form of muscular dystrophy due to mutations in the dystrophin gene.
However, its pathological process remains unknown and there is a lack of
specific molecular biomarkers. The aim of our study is to explore key regulatory
connections underlying the progression of DMD.
MATERIALS AND METHODS: The gene expression profile dataset GSE38417 of DMD was
obtained from the Gene Expression Omnibus (GEO) database. The differentially
expressed genes (DEGs) between DMD patients and healthy controls were screened
using geo2R, followed by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene
Ontology (GO) pathway enrichment analyses. Then a protein-protein interaction
(PPI) network and sub-network of modules were constructed. To investigate the
regulatory network underlying DMD, a global triple network including miRNAs,
mRNAs and transcription factors (TFs) was constructed.
RESULTS: A total of 1811 DEGs were found between the DMD and control groups,
among which HERC5, SKP2 and FBXW5 were defined as hub genes with a degree of
connectivity >35 in the PPI network. Furthermore, the five TFs ZNF362, ATAT1,
SPI1, TCF12 and ABCF2, as well as the eight miRNAs miR-124a, miR-200b/200c/429,
miR-19a/b, miR-23a/b, miR-182, miR-144, miR-498 and miR-18a/b were identified as
playing crucial roles in the molecular pathogenesis of DMD.
CONCLUSIONS: This paper provides a comprehensive perspective on the
miRNA-TF-mRNA co-regulatory network underlying DMD, although the bioinformatic
findings need further validation in future studies. BACKGROUND: Therapeutic trials are critical to improving outcomes for
individuals diagnosed with Duchenne muscular dystrophy (DMD). Understanding
predictors of clinical trial participation could maximize enrollment.
METHODS: Data from six sites (Colorado, Iowa, Piedmont region North Carolina,
South Carolina, Utah, and western New York) of the Muscular Dystrophy
Surveillance, Tracking, and Research Network (MD STARnet) were analyzed.
Clinical trial participation and individual-level clinical and sociodemographic
characteristics were obtained from medical records for the 2000-2015 calendar
years. County-level characteristics were determined from linkage of the most
recent county of residence identified from medical records and publicly
available federal datasets. Fisher's exact and Wilcoxon two-sample tests were
used with statistical significance set at one-sided p-value (<0.05) based on the
hypothesis that nonparticipants had fewer resources.
RESULTS: Clinical trial participation was identified among 17.9% (MD STARnet
site: 3.7-27.3%) of 358 individuals with DMD. Corticosteroids, tadalafil, and
ataluren (PTC124) were the most common trial medications recorded. Fewer
non-Hispanic blacks or Hispanics than non-Hispanic whites participated in
clinical trials. Trial participants tended to reside in counties with lower
percentages of non-Hispanic blacks. Conclusion: Understanding characteristics
associated with clinical trial participation is critical for identifying
participation barriers and generalizability of trial results. MD STARnet is
uniquely able to track clinical trial participation through surveillance and
describe patterns of participation. Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) phenotypes
are used to describe disease progression in affected individuals. However,
considerable heterogeneity has been observed across and within these two
phenotypes, suggesting a spectrum of severity rather than distinct conditions.
Characterizing the phenotypes and subphenotypes aids researchers in the design
of clinical studies and clinicians in providing anticipatory guidance to
affected individuals and their families. Using data from the Muscular Dystrophy
Surveillance, Tracking, and Research Network (MD STARnet), we used K-means
cluster analysis to group phenotypically similar males with pediatric-onset
dystrophinopathy. We identified four dystrophinopathy clusters: Classical BMD,
Classical DMD, late ambulatory DMD, and severe DMD. The clusters that we
identified align with both 'classical' and 'non-classical' dystrophinopathy
described in the literature. Individuals with dystrophinopathies have
heterogenous clinical presentations that cluster into phenotypically similar
groups. Use of clinically-derived phenotyping may provide a clearer
understanding of disease trajectories, reduce variability in study results, and
prevent exclusion of certain cohorts from analysis. Findings from studying
subphenotypes may ultimately improve our ability to predict disease progression. Early clinical trials of therapies to treat Duchenne muscular dystrophy (DMD), a
fatal genetic X-linked pediatric disease, have been designed based on the
limited understanding of natural disease progression and variability in clinical
measures over different stages of the continuum of the disease. The objective
was to inform the design of DMD clinical trials by developing a disease
progression model-based clinical trial simulation (CTS) platform based on
measures commonly used in DMD trials. Data were integrated from past studies
through the Duchenne Regulatory Science Consortium founded by the Critical Path
Institute (15 clinical trials and studies, 1505 subjects, 27,252 observations).
Using a nonlinear mixed-effects modeling approach, longitudinal dynamics of five
measures were modeled (NorthStar Ambulatory Assessment, forced vital capacity,
and the velocities of the following three timed functional tests: time to stand
from supine, time to climb 4 stairs, and 10 meter walk-run time). The models
were validated on external data sets and captured longitudinal changes in the
five measures well, including both early disease when function improves as a
result of growth and development and the decline in function in later stages.
The models can be used in the CTS platform to perform trial simulations to
optimize the selection of inclusion/exclusion criteria, selection of measures,
and other trial parameters. The data sets and models have been reviewed by the
US Food and Drug Administration and the European Medicines Agency; have been
accepted into the Fit-for-Purpose and Qualification for Novel Methodologies
pathways, respectively; and will be submitted for potential endorsement by both
agencies. |
What links immune response pathways to ALS? | Microglia, which are the primary immune cells of the central nervous system, are strongly implicated in ALS, their activation being correlated with various clinical features, and inflammatory microglial responses being correlated withe disease progression. The immune response may be implicated in other ways with ALS molecular pathology. such as through inflammatory regulation and circulating interleukins. It is possible the T cell receptor signalling and activation is involved. It is also possible that the innate / non-specific immune system is involved - i.e. immune protection against foreign substances, viruses, and bacteria. | The immune system has been found to be involved with positive and negative
effects in the nervous system of amyotrophic lateral sclerosis (ALS) patients.
In general, T cells, B cells, NK cells, mast cells, macrophages, dendritic
cells, microglia, antibodies, complement and cytokines participate in limiting
damage. Several mechanisms of action, such as production of neurotrophic growth
factors and interaction with neurons and glial cells, have been shown to
preserve these latter from injury and stimulate growth and repair. The immune
system also participates in proliferation of neural progenitor stem cells and
their migration to sites of injury and this activity has been documented in
various neurologic disorders including traumatic injury, ischemic and
hemorrhagic stroke, multiple sclerosis, infection, and neurodegenerative
diseases (Alzheimer's disease, Parkinson's disease and ALS). Many therapies have
been shown to stimulate the protective and regenerative aspects of the immune
system in humans, such as intravenous immunoglobulins, and other experimental
interventions such as vaccination, minocycline, antibodies and neural stem
cells, have shown promise in animal models of ALS. Consequently, several
immunosuppressive and immunomodulatory therapies have been tried in ALS,
generally with no success, in particular intravenous immunoglobulins. The
multiple aspects of the immune response in ALS are beginning to be appreciated,
and their potential as pharmacologic targets in neurologic disease is being
explored. Accumulating evidence from mice expressing ALS-causing mutations in superoxide
dismutase (SOD1) has implicated pathological immune responses in motor neuron
degeneration. This includes microglial activation, lymphocyte infiltration, and
the induction of C1q, the initiating component of the classic complement system
that is the protein-based arm of the innate immune response, in motor neurons of
multiple ALS mouse models expressing dismutase active or inactive SOD1 mutants.
Robust induction early in disease course is now identified for multiple
complement components (including C1q, C4, and C3) in spinal cords of SOD1
mutant-expressing mice, consistent with initial intraneuronal C1q induction,
followed by global activation of the complement pathway. We now test if this
activation is a mechanistic contributor to disease. Deletion of the C1q gene in
mice expressing an ALS-causing mutant in SOD1 to eliminate C1q induction, and
complement cascade activation that follows from it, is demonstrated to produce
changes in microglial morphology accompanied by enhanced loss, not retention, of
synaptic densities during disease. C1q-dependent synaptic loss is shown to be
especially prominent for cholinergic C-bouton nerve terminal input onto motor
neurons in affected C1q-deleted SOD1 mutant mice. Nevertheless, overall onset
and progression of disease are unaffected in C1q- and C3-deleted ALS mice, thus
establishing that C1q induction and classic or alternative complement pathway
activation do not contribute significantly to SOD1 mutant-mediated ALS
pathogenesis in mice. The immune system is inextricably linked with many neurodegenerative diseases
including amyotrophic lateral sclerosis (ALS), a devastating neuromuscular
disorder affecting motor cell function with an average survival of 3 years from
symptoms onset. In ALS, there is a dynamic interplay between the resident innate
immune cells, that is, microglia and astrocytes, which may become progressively
harmful to motor neurons. Although innate and adaptive immune responses are
associated with progressive neurodegeneration, in the early stages of ALS immune
activation pathways are primarily considered to be beneficial promoting neuronal
repair of the damaged tissues, though a harmful effect of T cells at this stage
of disease has also been observed. In addition, although auto-antibodies against
neuronal antigens are present in ALS, it is unclear whether these arise as a
primary or secondary event to neuronal damage, and whether the auto-antibodies
are indeed pathogenic. Understanding how the immune system contributes to the
fate of motor cells in ALS may shed light on the triggers of disease as well as
on the mechanisms contributing to the propagation of the pathology. Immune
markers may also act as biomarkers while pathways involved in immune action may
be targets of new therapeutic strategies. Here, we review the modalities by
which the immune system senses the core pathological process in motor neuron
disorders, focusing on tissue-specific immune responses in the neuromuscular
junction and in the neuroaxis observed in affected individuals and in animal
models of ALS. We elaborate on existing data on the immunological fingerprint of
ALS that could be used to identify clues on the disease origin and patterns of
progression. BACKGROUND: The peripheral immune system is implicated in modulating microglial
activation, neurodegeneration and disease progression in amyotrophic lateral
sclerosis (ALS). Specifically, there is reduced thymic function and regulatory T
cell (Treg) number in ALS patients and mutant superoxide dismutase 1 (SOD1)
mice, while passive transfer of Tregs ameliorates disease in mutant SOD1 mice.
Here, we assessed the effects of augmenting endogenous CD4+ T cell number by
stimulating the thymus using surgical castration on the phenotype of transgenic
SOD1(G93A) mice.
METHOD: Male SOD1(G93A) mice were castrated or sham operated, and weight loss,
disease onset and progression were examined. Thymus atrophy and blood CD4+, CD8+
and CD4+ FoxP3+ T cell numbers were determined by fluorescence activated cell
sorting (FACS). Motor neuron counts, glial cell activation and androgen receptor
(AR) expression in the spinal cord were investigated using immunohistochemistry
and Western blotting. Differences between castrated and sham mice were analysed
using an unpaired t test or one-way ANOVA.
RESULTS: Castration significantly increased thymus weight and total CD4+ T cell
numbers in SOD1(G93A) mice, although Tregs levels were not affected. Despite
this, disease onset and progression were similar in castrated and sham
SOD1(G93A) mice. Castration did not affect motor neuron loss or astrocytic
activation in spinal cords of SOD1(G93A) mice; however, microglial activation
was reduced, specifically M1 microglia. We also show that AR is principally
expressed in spinal motor neurons and progressively downregulated in spinal
cords of SOD1(G93A) mice from disease onset which is further enhanced by
castration.
CONCLUSIONS: These results demonstrate that increasing thymic function and CD4+
T cell number by castration confers no clinical benefit in mutant SOD1 mice,
which may reflect an inability to stimulate neuroprotective Tregs. Nonetheless,
castration decreases M1 microglial activation in the spinal cord without any
clinical improvement and motor neuron rescue, in contrast to other approaches to
suppress microglia in mutant SOD1 mice. Lastly, diminished AR expression in
spinal motor neurons, which links to another motor neuron disorder, spinal
bulbar muscular atrophy (SBMA), may contribute to ALS pathogenesis and suggests
a common disease pathway in ALS and SBMA mediated by disruption of AR signalling
in motor neurons. OBJECTIVE: To evaluate the combined blood expression of neuromuscular and
inflammatory biomarkers as predictors of disease progression and prognosis in
amyotrophic lateral sclerosis (ALS).
METHODS: Logistic regression adjusted for markers of the systemic inflammatory
state and principal component analysis were carried out on plasma levels of
creatine kinase (CK), ferritin, and 11 cytokines measured in 95 patients with
ALS and 88 healthy controls. Levels of circulating biomarkers were used to study
survival by Cox regression analysis and correlated with disease progression and
neurofilament light chain (NfL) levels available from a previous study.
Cytokines expression was also tested in blood samples longitudinally collected
for up to 4 years from 59 patients with ALS.
RESULTS: Significantly higher levels of CK, ferritin, tumor necrosis factor
(TNF)-α, and interleukin (IL)-1β, IL-2, IL-8, IL-12p70, IL-4, IL-5, IL-10, and
IL-13 and lower levels of interferon (IFN)-γ were found in plasma samples from
patients with ALS compared to controls. IL-6, TNF-α, and IFN-γ were the most
highly regulated markers when all explanatory variables were jointly analyzed.
High ferritin and IL-2 levels were predictors of poor survival. IL-5 levels were
positively correlated with CK, as was TNF-α with NfL. IL-6 was strongly
associated with CRP levels and was the only marker showing increasing expression
towards end-stage disease in the longitudinal analysis.
CONCLUSIONS: Neuromuscular pathology in ALS involves the systemic regulation of
inflammatory markers mostly active on T-cell immune responses. Disease
stratification based on the prognostic value of circulating inflammatory markers
could improve clinical trials design in ALS. Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder
characterized by damage of motor neurons. Recent reports indicate that
inflammatory responses occurring within the central nervous system contribute to
the pathogenesis of ALS. We aimed to investigate disease-specific gene
expression associated with neuroinflammation by conducting transcriptome
analysis on fibroblasts from three patients with sporadic ALS and three normal
controls. Several pathways were found to be upregulated in patients with ALS,
among which the toll-like receptor (TLR) and NOD-like receptor (NLR) signaling
pathways are related to the immune response. Genes-toll-interacting protein
(TOLLIP), mitogen-activated protein kinase 9 (MAPK9), interleukin-1β (IL-1β),
interleukin-8 (IL-8), and chemokine (C-X-C motif) ligand 1 (CXCL1)-related to
these two pathways were validated using western blotting. This study validated
the genes that are associated with TLR and NLR signaling pathways from different
types of patient-derived cells. Not only fibroblasts but also induced
pluripotent stem cells (iPSCs) and neural rosettes from the same origins showed
similar expression patterns. Furthermore, expression of TOLLIP, a regulator of
TLR signaling pathway, decreased with cellular aging as judged by changes in its
expression through multiple passages. TOLLIP expression was downregulated in ALS
cells under conditions of inflammation induced by lipopolysaccharide. Our data
suggest that the TLR and NLR signaling pathways are involved in pathological
innate immunity and neuroinflammation associated with ALS and that TOLLIP,
MAPK9, IL-1β, IL-8, and CXCL1 play a role in ALS-specific immune responses.
Moreover, changes of TOLLIP expression might be associated with progression of
ALS. Author information:
(1)Department of Neuroscience and Pathobiology, Research Institute of
Environmental Medicine, Nagoya University, Nagoya, Japan.
(2)Laboratory for Motor Neuron Disease, RIKEN Brain Science Institute, Wako,
Japan.
(3)Department of Neurology, Graduate School of Medicine, Kyoto University,
Kyoto, Japan.
(4)Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science
Institute, Wako, Japan.
(5)Department of Cell Biology and Neuroscience, Juntendo University Graduate
School of Medicine, Tokyo, Japan.
(6)Division of Pharmacology, Faculty of Pharmacy, Keio University, Tokyo, Japan.
(7)Department of Mucosal Immunology, School of Medicine, Chiba University,
Chiba, Japan.
(8)Division of Innate Immune Regulation, International Research and Development
Center for Mucosal Vaccines, Institute of Medical Science, The University of
Tokyo, Tokyo, Japan.
(9)Laboratory of Host Defense, World Premier International Immunology Frontier
Research Center, and Department of Host Defense, Research Institute for
Microbial Diseases, Osaka University, Osaka, Japan.
(10)Department of Cellular and Molecular Neuropathology, Juntendo University
Graduate School of Medicine, Tokyo, Japan.
(11)Department of Neuroscience and Pathobiology, Research Institute of
Environmental Medicine, Nagoya University, Nagoya, Japan.
[email protected].
(12)Laboratory for Motor Neuron Disease, RIKEN Brain Science Institute, Wako,
Japan. [email protected].
(13)Department of Neuroscience and Pathobiology, Nagoya University Graduate
School of Medicine, Nagoya, Japan. [email protected]. Motor Neuron Disease (MND) is a fatal neurodegenerative condition, which is
characterized by the selective loss of the upper and lower motor neurons. At the
sites of motor neuron injury, accumulation of activated microglia, the primary
immune cells of the central nervous system, is commonly observed in both human
post mortem studies and animal models of MND. Microglial activation has been
found to correlate with many clinical features and importantly, the speed of
disease progression in humans. Both anti-inflammatory and pro-inflammatory
microglial responses have been shown to influence disease progression in humans
and models of MND. As such, microglia could both contribute to and protect
against inflammatory mechanisms of pathogenesis in MND. While murine models have
characterized the microglial response to MND, these studies have painted a
complex and often contradictory picture, indicating a need for further
characterization in humans. This review examines the potential role microglia
play in MND in human and animal studies. Both the pro-inflammatory and
anti-inflammatory responses will be addressed, throughout the course of disease,
followed by the potential of microglia as a target in the development of
disease-modifying treatments for MND. PURPOSE OF REVIEW: Neuroinflammation is an important mediator of the
pathogenesis of disease in amyotrophic lateral sclerosis (ALS). Genetic
mutations such as C9orf72 have begun to define the numerous cell autonomous
pathways that initiate motor neuron injury. Yet, it is the signalling to
surrounding glia and peripherally derived immune cells that initiates the
noncell autonomous inflammatory process and promotes self-propagating motor
neuron cell death. The purpose of this review is to explore the systemic
immune/inflammatory contributions to the pathogenesis of ALS: what are the
peripheral pro-inflammatory signatures, what initiates their presence and do
they represent potential therapeutic targets.
RECENT FINDINGS: In ALS, motor neuron cell death is initiated by multiple cell
autonomous pathways leading to misfolded proteins, oxidative stress, altered
mitochondria, impaired autophagy and altered RNA metabolism, which collectively
promote noncell autonomous inflammatory reactivity. The resulting disease is
characterized by activated microglia and astrocytes as well as peripherally
derived pro-inflammatory innate and adaptive immune cells. In this unrelenting
disorder, circulating blood monocytes and natural killer cells are
pro-inflammatory. Furthermore, regulatory T lymphocytes are dysfunctional, and
pro-inflammatory cytokines and acute phase proteins are elevated.
SUMMARY: The collective dysregulation of cells and cytokines in patients with
ALS accurately reflect increased disease burdens, more rapid progression rates
and reduced survival times, reinforcing the concept of ALS as a disorder with
extensive systemic pro-inflammatory responses. These increased systemic
pro-inflammatory immune constituents provide potentially meaningful therapeutic
targets. |
Which vitamin deficiencies may present with neurologic signs or symptoms? | Many vitamin deficiencies have been described as a cause of neurologic signs and symptoms. For instance, vitamin B12 deficiency can cause several types of neurological manifestations, such as subacute combined degeneration of the spinal cord, ataxia, peripheral polyneuropathy, optic nerve neuropathy, and cognitive disorders. In addition, vitamin B1 (Thiamine) and B6 (Pyridoxine) deficiency can both cause peripheral neuropathy. Specifically, vitamin B1 deficiency can also cause confusion, ophthalmoplegia, nystagmus, and ataxia in the context of beriberi and Wernicke's encephalopathy. Finally, vitamin A deficiency has been described to cause retinal change-related visual defects and subsequent vision loss. | We reviewed 153 episodes of cobalamin deficiency involving the nervous system
that occurred in 143 patients seen over a recent 17-year period at 2 New York
City hospitals. Pernicious anemia was the most common underlying cause of the
deficiency. Neurologic complaints, most commonly paresthesias or ataxia, were
the first symptoms of Cbl deficiency in most episodes. The median duration of
symptoms before diagnosis and treatment with vitamin B12 was 4 months, although
long delays in diagnosis occurred in some patients. Diminished vibratory
sensation and proprioception in the lower extremities were the most common
objective findings. A wide variety of neurologic symptoms and signs were
encountered, however, including ataxia, loss of cutaneous sensation, muscle
weakness, diminished or hyperactive reflexes, spasticity, urinary or fecal
incontinence, orthostatic hypotension, loss of vision, dementia, psychoses, and
disturbances of mood. Multiple neurologic syndromes were often seen in a single
patient. In 42 (27.4%) of the 153 episodes, the hematocrit was normal, and in 31
(23.0%), the mean corpuscular volume was normal. Neutropenia and
thrombocytopenia were unusual even in anemic patients. In noemic patients in
whom diagnosis was delayed, neurologic progression frequently occurred although
the hematocrit remained normal. In 27 episodes, the serum cobalamin
concentration was only moderately decreased (in the range of 100-200 pg/ml) and
in 2 the serum level was normal. Neurologic impairment, as assessed by a
quantitative severity score, was judged to be mild in 99 episodes, moderate in
39 and severe in 15. Severity of neurologic dysfunction before treatment was
clearly related to the duration of symptoms prior to diagnosis. In addition, the
hematocrit correlated significantly with severity, independent of the longer
duration of symptoms in noemic patients. Four patients experienced transient
neurologic exacerbations soon after beginning treatment with cyanocobalamin,
with subsequent recovery. Followup evaluation was adequate to assess the
neurologic response to vitamin B12 therapy in 121 episodes. All patients
responded, and in 57 (47.1%), recovery was complete, with no remaining symptoms
or findings on examination. The severity score was reduced by 50% or greater
after treatment in 91% of the episodes. Residual long-term moderate or severe
neurologic disability was noted following only 7 (6.3%) episodes. The extent of
neurologic involvement after treatment was strongly related to that before
therapy as well as to the duration of symptoms. The percent improvement over
baseline neurologic status after treatment was inversely related to duration of
symptoms and hematocrit. Some evidence of response was always seen during the
first 3 months of treatment.(ABSTRACT TRUNCATED AT 400 WORDS) We describe nine patients with fat malabsorption in whom a spectrum of vitamin E
deficiency was present. Early deficiency was generally asymptomatic, and
intermediate deficiency produced some impairment. Ataxia, weakness, reflex
changes, impaired vision, and pigment retinopathy were associated with chronic,
advanced deficiency. In the last group, delayed central somatosensory conduction
and amplitude reduction of the electroretinogram were present. In adults, a
severe vitamin E deficiency state existed for more than 5 years before producing
measurable neurologic damage. The clinical picture is less homogeneous than
previously suggested, and electrophysiologic abnormalities need not predate
clinical dysfunction. It is well known that the neurologic manifestations of vitamin B12 deficiency
can occur in the absence of anemia. The authors recently observed two elderly
patients who presented to a chronic care institution with the diagnosis of
dementia, and in both individuals low serum B12 levels were found in conjunction
with abnormal Schilling tests. In neither of these two patients was there anemia
or macrocytosis. After receiving parenteral B12 injections there was improvement
noted in cognitive functions as well as in activities of daily living. The
authors are reporting these patients to alert clinicians to the fact that
pernicious anemia in the elderly can first present with low serum B12 levels and
neurologic abnormalities in the absence of anemia or macrocytosis. The activities of the red blood cell enzymes transketolase, glutathione
reductase, and glutamic oxaloacetate transaminase were measured with and without
in vitro addition of their respective coenzyme components thiamine, riboflavin,
and pyridoxine in a group of patients with neurological disorders which may have
been caused by malnutrition, intestinal malabsorption, hepatic failure or
neoplasms arising outside the nervous system. The incidence of thiamine
deficiency was 31%, of riboflavin deficiency 22% and of pyridoxine deficiency
6%. Alcoholics in particular suffered from deficiencies of vitamin B 1, and B 2.
There was a correlation of vitamin B 1 and B 2 deficiency and signs of a
cerebellar and/or brainstem lesion. The most frequent symptoms in this
connection were gait disturbances and oculomotor signs like spontaneous and gaze
nystagmus, disturbed eye tracking, diminished optokinetic nystagmus, decreased
ability to suppress vestibular nystagmus by fixation. These signs hardly ever
occurred in alcoholic patients who showed no deficiency of vitamin B 1, B 2 or B
6. Whenever they do appear, a vitamin B supplementation has to be performed in
order to prevent the manifestation of Wernicke's encephalopathy, cerebral or
cerebellar atrophy. Alcoholics showed the same incidence of polyneuropathy,
whether they suffered from a deficiency of B vitamins or not. Deficiencies of
vitamin B 1, B 2 or B 6 were also found in patients with intestinal
malabsorption and polyneuropathy, diabetic polyneuropathy, optic atrophy,
myelopathy and cerebellar ataxia of unknown etiology, neurological
manifestations of neoplasms arising outside the nervous system, B 12
myeloencephalopathy and Thévenard's syndrome. Thirteen children, aged 10 months to 20 years, presenting with chronic
cholestasis from the first month of life and with low serum levels of vitamins A
and/or E, have been investigated for neurological and ophthalmological symptoms.
Clinical findings consisted of 4 types: peripheral neuropathy; cerebellar
dysfunction; abnormalities of eye movement, and retinal degenerative changes.
The results of electrophysiological and morphological studies of muscle and
nerves were consistent with neurono-axonal degeneration. Electrical
abnormalities of the retina, especially a decrease of the b wave of
electroretinogram, appear to be the first sign of the syndrome, allowing early
detection. Evidence for vitamin deficiency (E or E+A) suggests substitutive
parenteral treatment in such patients. Vitamin E malabsorption and deficiency during chronic childhood cholestasis has
been associated with a progressive ataxic neurologic syndrome. Hyporeflexia, the
first sign of neurologic dysfunction, may begin prior to age 2 years, but severe
symptoms do not develop until age 5 to 10 years. To establish the age of onset
of neuropathologic lesions, we prospectively evaluated four young children with
severe cholestasis. Malabsorption and deficiency of vitamin E were documented by
low serum vitamin E concentrations, low serum vitamin E to total serum lipids
ratios, elevated hydrogen peroxide hemolysis, and impaired absorption of a
pharmacologic dose of alpha-tocopherol. Abnormal neurologic findings in two
patients were limited to areflexia, ptosis, mild truncal ataxia, and hypotonia;
two patients had minimal signs of neurologic dysfunction. Sural nerve histology
at age 6 to 25 months revealed a degenerative axonopathy involving large-caliber
myelinated fibers, but without quantitative axonal loss. Muscle histology and
histochemistry tests yielded normal results. Our study suggests that neurologic
injury may occur during the first two years of life in vitamin E-deficient
children with cholestatic hepatobiliary disease, obligating aggressive attempts
at correcting this deficiency state at a very young age. Children deficient in vitamin E have various neurologic symptoms. 2 cases
representing different mechanisms of this vitamin deficiency are reported. A
15-year-old boy with fat malabsorption due to cystic fibrosis who was diagnosed
as being vitamin E deficient (< 0.5 mg/l), had typical neuropathies. On the
other hand, a 12-year-old Beduin girl had isolated vitamin E deficiency, as well
as neurological symptoms suggestive of Friedrich's ataxia. Vitamin E
supplementation by intramuscular injection in the first case and per os in the
second led to significant improvement in neurological symptoms. Ataxia with vitamin E deficiency is an autosomal recessive condition associated
with a defect in the a-tocopherol transfer protein. Clinically it manifests as a
progressive ataxia with a phenotype resembling that of Friedreich's ataxia.
There is some evidence that progression of neurological symptoms is prevented by
vitamin E therapy. A patient is described who was given a clinical diagnosis of
Friedreich's ataxia. Molecular genetic analysis showed the absence of the
frataxin gene expansion. Subsequent vitamin E assay showed deficiency and a
diagnosis of ataxia with vitamin E deficiency was made. It is recommended that
all patients with ataxia of unknown cause should have vitamin E deficiency
excluded. When a diagnosis of Friedreich's ataxia is considered patients should
have frataxin analysis in addition. Further, neurologists should be aware that
ataxia with vitamin E deficiency may present as "mutation negative" Friedreich's
ataxia. Vitamin B(12) deficiency (B(12)D) has a wide variety of neurological symptoms
and signs. However, cerebellar dysfunction and cranial neuropathies other than
optic neuropathy have been rarely reported. Herein, we describe two cases of
unusual neurological manifestations of B(12)D. One patient showed prominent
hoarseness with vocal cord paralysis, myelopathy, and peripheral neuropathy. The
other had gait disturbance, lateral gaze limitation and cerebellar dysfunction
in addition to the typical manifestations of subacute combined degeneration.
Vitamin B(12) deficiency can rarely affect cerebellum and cranial nerves other
than optic nerve. We report herein our interesting case series of 15 infants admitting with
neurological symptoms who were found to have vitamin B12 deficiency. Infants who
were admitted to our hospital between 2004 and 2007 with neurological symptoms
and were found to have vitamin B12 deficiency were included in this study. Data
regarding clinical and laboratory features were obtained. Of 15 infants, 9 were
boys (60%) and 6 were girls (40%). The mean age was 11.7 months. Anorexia,
pallor, hypotonia, and neurodevelopmental retardation were present in all
infants. Seizures and tremor were observed in 46.6% (7/15) and 33% (5/15) of
patients, respectively. Seizures were generalized tonic-clonic in 4 patients,
generalized tonic in 1 patient and focal in 2 patients. Four patients had tremor
on admission and 1 patient had occurrence after vitamin B12 treatment. Vitamin
B12 deficiency may lead to serious neurological deficits in addition to
megaloblastic anemia. Persistent neurological damage can be prevented with early
diagnosis and treatment. We believe that a thorough clinical and neurological
assessment might prevent failure to notice rare but possible vitamin B12
deficiency in infants with neurological deficits and neurodevelopmental
retardation. Nearly two thirds of American adults are either overweight or obese.
Accordingly, bariatric surgery experienced explosive growth during the past
decade. Current estimates place the worldwide volume of bariatric procedures at
greater than 300,000 cases annually. Micronutrient deficiencies are
well-described following bariatric surgery, and they may present with
devastating and sometimes irreversible neurologic manifestations. Clinical
symptoms range from peripheral neuropathy to encephalopathy, and are most
commonly caused by thiamine, copper, and B(12) deficiencies. Long lists of psychiatric illness or symptoms have been documented to be caused
by vitamin B12 deficiency. We describe an atypical case of a young adult who
presented with predomit negative symptoms followed by neurological symptoms
consistent with vitamin B12 deficiency. The symptoms showed complete remission
after vitamin B12 supplementation. The uniqueness of this case is that vitamin
B12 deficiency presented with predomit negative symptoms without other
psychotic and manic symptoms, which has not been reported previously. Vitamin B12 deficiency is a common cause of neuropsychiatric symptoms in elderly
persons. Malabsorption accounts for the majority of cases. Vitamin B12
deficiency has been associated with neurologic, cognitive, psychotic, and mood
symptoms, as well as treatment-resistance. Clinician awareness should be raised
to accurately diagnose and treat early deficiencies to prevent irreversible
structural brain damage, because current practice can be ineffective at
identifying cases leading to neuropsychiatric sequelae. This clinical review
focuses on important aspects of the recognition and treatment of vitamin B12
deficiency and neuropsychiatric manifestations of this preventable illness in
elderly patients. BACKGROUND: Vitamin B12 deficiency is often diagnosed with hematological
manifestations of megaloblastic macrocytic anemia, which is usually the initial
presentation. Neurological symptoms are often considered to be late
manifestations and usually occur after the onset of anemia. Sub acute combined
cord degeneration, which is a rare cause of myelopathy is however the commonest
neurological manifestation of vitamin B12 deficiency.
CASE PRESENTATION: We present a case of a 66 year old Sinhalese Sri Lankan
female, who is a strict vegetarian, presenting with one month's history
suggestive of Sub-acute combined cord degeneration in the absence of
haematological manifestations of anaemia. Her Serum B12 levels were
significantly low, after which she was treated with hydroxycobalamine
supplementation, showing marked clinical improvement of symptoms, with
normalization of serum B12 levels. Hence, the diagnosis of vitamin B12
deficiency was confirmed retrospectively.
CONCLUSION: Vitamin B12 deficiency could rarely present with neurological
manifestations in the absence of anaemia. Therefore a high index of suspicion is
necessary for the early diagnosis and prompt treatment in order to reverse
neurological manifestations, as the response to treatment is inversely
proportionate to the severity and duration of the disease. BACKGROUND: Vision loss resulting from thiamine deficiency is a recognized
complication of bariatric surgery. Most patients with such vision loss have
Wernicke encephalopathy with characteristic changes seen on neuroimaging. Other
patients may have retinal hemorrhages, optic disc edema, and peripheral
neuropathy without Wernicke encephalopathy. The risk for thiamine deficiency is
potentiated by the presence of prolonged vomiting.
CASE REPORT: A 37-year-old female presented with abrupt onset of vision loss and
peripheral neuropathy following bariatric surgery. She had a history of
prolonged vomiting postoperatively. Examination of the posterior segment of the
eye revealed optic disc edema and large retinal hemorrhages bilaterally.
Metabolic workup demonstrated thiamine deficiency. She responded quickly to
parenteral thiamine therapy with recovery of normal vision and resolution of
ophthalmologic findings.
CONCLUSION: Patients who undergo bariatric surgery and have a thiamine
deficiency can present with visual symptoms and ophthalmologic findings only
visible by fundoscopy prior to developing more severe and potentially
irreversible complications from the vitamin deficiency. Early detection of
intraocular changes resulting from thiamine deficiency and initiation of therapy
could prevent more devastating neurologic manifestations. Our case supports the
consideration of a prospective study aimed at determining the true incidence of
ocular and visual changes such as retinal hemorrhage, optic disc edema, and
peripapillary telangiectasia in patients following bariatric surgery. Jitteriness and tremors in the newborn period typically precipitate an
extensive, invasive, and expensive search for the etiology. Vitamin D deficiency
has not been historically included in the differential of tremors. We report a
shivering, jittery newborn who was subjected to a battery of testing, with the
only biochemical abnormality being vitamin D deficiency. A second case had chin
tremors and vitamin D deficiency. Review of our patients suggests that shudders,
shivers, jitteriness, or tremors may be the earliest sign of vitamin D
deficiency in the newborn. Neonates who present with these signs should be
investigated for vitamin D deficiency. The review discusses thesteps of vitamin B12 metabolism and its role in
maintaining of neurological functions. The term "vitamin B12 (cobalamin)" refers
to several substances (cobalamins) of a very similar structure. Cobalamin enters
the body with animal products. On the peripherу cobalamin circulates only in
binding with proteins transcobalamin I and II (complex cobalamin-transcobalamin
II is designated as "holotranscobalamin"). Holotranscobalamin is absorbed by
different cells, whereas transcobalamin I-binded vitamin B12 - only by liver and
kidneys. Two forms of cobalamin were identified as coenzymes of cellular
reactions which are methylcobalamin (in cytoplasm) and hydroxyadenosylcobalamin
(in mitochondria). The main causes of cobalamin deficiency are related to
inadequate intake of animal products, autoimmune gastritis, pancreatic
insufficiency, terminal ileum disease, syndrome of intestinal bacterial
overgrowth. Relative deficiency may be seen in excessive binding of vitamin B12
to transcobalamin I. Cobalamin deficiency most significantly affects functions
of blood, nervous system and inflammatory response. Anemia occurs in 13-15% of
cases; macrocytosis is an early sign. The average size of neutrophils and
monocytes is the most sensitive marker of megaloblastic hematopoiesis. The
demands in vitamin B12 are particularly high in nervous tissue. Hypovitaminosis
is accompanied by pathological lesions both in white and gray brain matter.
Several types of neurological manifestations are described: subacute combined
degeneration of spinal cord (funicular myelinosis), sensomotor polyneuropathy,
optic nerve neuropathy, cognitive disorders. The whole range of neuropsychiatric
disorders with vitamin B12 deficiency has not been studied well enough. Due to
certain diagnostic difficulties they are often regarded as "cryptogenic",
"reactive", "vascular» origin. Normal or decreased total plasma cobalamin level
could not a reliable marker of vitamin deficiency. In difficult cases the
content of holotranscobalamin, methylmalonic acid / homocysteine, and folate in
the blood serum should be investigated besides carefully analysis of clinical
manifestations. RATIONALE: There have been a few reported cases of subacute combined
degeneration (SCD) associated with vitamin E deficiency, but the period of
intestinal malabsorption was more than several years. We present a rare case of
acute onset SCD that occurred in a relatively short period of several weeks with
vitamin E deficiency related to small bowel obstruction.
PATIENT CONCERNS: A 50-year-old woman had abdominal pain. A small bowel
obstruction was suspected and conservative treatment was performed. She
underwent bowel surgery after 2 weeks without any improvement. Following the
operation, she was in a state of reduced consciousness. She was treated in an
intensive care unit. Her consciousness level gradually recovered to alert in a
week, but other symptoms such as ataxia, weakness on limbs, severe dysarthria,
and dysphagia occurred. Since then, she had spent nearly 6 weeks in a bed-ridden
state without improving.
DIAGNOSIS: SCD associated with vitamin E deficiency was confirmed by laboratory
investigations, electrophysiologic test, and whole spine magnetic resoce
imaging scans.
INTERVENTIONS: For vitamin E supplementation, she was administered a dose of
1200 mg/d. Physical therapy was focused on strengthening exercise, balance, and
walker gait training. Occupational therapy was focused on activities of daily
living training and dysphagia rehabilitation.
OUTCOMES: After 6 weeks, her muscle strengths and functional level were
substantially improved. The vitamin E level was recovered to normal range.
LESSONS: This case suggests that if neurological symptoms occur in patients with
intestinal obstruction, clinicians need to consider a deficiency of
micronutrients such as vitamin E and vitamin B12. Patients with short clinical
courses suffer less neurological damage and achieve faster recovery. Publisher: El déficit de vitamina B12 es una de las complicaciones más
importantes que puede producir el vegetarianismo. Los lactantes hijos de madres
vegetarianas tienen riesgo aumentado de deficiencia y de presentar compromiso
neurológico irreversible si esta no se identifica y corrige adecuadamente. Se
describe el caso de un lactante de un mes y veinte días que consultó por
episodios paroxísticos de mecanismo epileptógeno, en el cual los estudios
complementarios permitieron identificar un déficit de vitamina B12 como causa de
estos. Tras la confirmación diagnóstica, se instauró el tratamiento con vitamina
B12 intramuscular, con remisión completa de los síntomas, buena evolución
posterior y desarrollo psicomotor sin alteraciones. Teniendo en cuenta las
tendencias alimentarias actuales, es necesario incorporar, en la práctica
clínica habitual, la anamnesis nutricional materna detallada para detectar
precozmente el riesgo de déficit de esta vitamina y prevenirlo. Hyperemesis gravidarum is a complication of pregcy associated with severe
nausea and vomiting that can lead to fluid-electrolyte imbalances and
nutritional deficiencies. Wernicke's encephalopathy is a neurologic
manifestation of acute thiamine (vitamin B1) deficiency. We describe a case of
hyperemesis gravidarum presenting with gait ataxia and nystagmus which led to a
diagnosis of Wernicke's encephalopathy. BACKGROUND: Nutritional visual defects are apparently uncommon nowadays in
developed nations. Retinal change-related visual defects caused by
hypovitaminoses may be underdiagnosed.
AIM OF THE STUDY: To investigate the retinal structural and functional changes
in a patient with multivitamin deficiency before and during vitamin
supplementation.
METHODS: A 51-year-old female had been on vegetarian diet as a child, and on
restrict vegan diet during the last 2 years, developing severe bilateral
deterioration of visual function and polyneuropathy. Blood test revealed low
levels of vitamin A, B6 and D. The patient underwent examinations with optical
coherence tomography (OCT), computerized visual field examination (VF),
electroretinography (ERG), visual evoked potentials (VEP) and neurography before
and after vitamin supplementation.
RESULTS: Visual acuity (VA) was 20/1000 and VF examination showed central
scotoma in both eyes. Color vision was significantly affected. Full-field ERG
showed normal rod and cone function, but a clearly reduced central peak was
registered in multifocal ERG (mf-ERG), indicating impaired fovea function. VEP
showed delayed latency and low amplitude of P100 in both eyes. Neurography
showed sensory polyneuropathy. OCT showed significant thinning of macular
ganglion cell plus inner plexiform layer (GCIPL) with rapid progression. Retinal
nerve fiber layer (RNFL) was preserved and normal, which is in contrast to
neuroinflammatory conditions. After 2.5 years of multivitamin supplementation,
the visual functions were improved. GCIPL thickness was stable without further
deterioration.
CONCLUSIONS: Multivitamin deficiency results in progressive thinning of GCIPL
with severe visual deterioration. In contrast to neuroinflammation, RNFL is
preserved and normal. Stabilized GCIPL during vitamin supplementation was
associated with improved visual function. OCT provides a sensitive and objective
measure for differential diagnosis, monitoring retinal change and response to
therapy. |
Which are the uses of deep learning models in Duchenne Muscular Dystrophy? | Deep Learning of Ultrasound Imaging for Evaluating Ambulatory Function of Individuals with Duchenne Muscular Dystrophy. | BACKGROUND: Children with physical impairments are at a greater risk for obesity
and decreased physical activity. A better understanding of physical activity
pattern and energy expenditure (EE) would lead to a more targeted approach to
intervention.
OBJECTIVE: This study focuses on studying the use of machine-learning algorithms
for EE estimation in children with disabilities. A pilot study was conducted on
children with Duchenne muscular dystrophy (DMD) to identify important factors
for determining EE and develop a novel algorithm to accurately estimate EE from
wearable sensor-collected data.
METHODS: There were 7 boys with DMD, 6 healthy control boys, and 22 control
adults recruited. Data were collected using smartphone accelerometer and
chest-worn heart rate sensors. The gold standard EE values were obtained from
the COSMED K4b2 portable cardiopulmonary metabolic unit worn by boys (aged 6-10
years) with DMD and controls. Data from this sensor setup were collected
simultaneously during a series of concurrent activities. Linear regression and
nonlinear machine-learning-based approaches were used to analyze the
relationship between accelerometer and heart rate readings and COSMED values.
RESULTS: Existing calorimetry equations using linear regression and nonlinear
machine-learning-based models, developed for healthy adults and young children,
give low correlation to actual EE values in children with disabilities
(14%-40%). The proposed model for boys with DMD uses ensemble machine learning
techniques and gives a 91% correlation with actual measured EE values (root mean
square error of 0.017).
CONCLUSIONS: Our results confirm that the methods developed to determine EE
using accelerometer and heart rate sensor values in normal adults are not
appropriate for children with disabilities and should not be used. A much more
accurate model is obtained using machine-learning-based nonlinear regression
specifically developed for this target population. INTRODUCTION: Golden retriever muscular dystrophy (GRMD) is a spontaneous
X-linked canine model of Duchenne muscular dystrophy that resembles the human
condition. Muscle percentage index (MPI) is proposed as an imaging biomarker of
disease severity in GRMD.
METHODS: To assess MPI, we used MRI data acquired from nine GRMD samples using a
4.7 T small-bore scanner. A machine learning approach was used with eight raw
quantitative mapping of MRI data images (T1m, T2m, two Dixon maps, and four
diffusion tensor imaging maps), three types of texture descriptors (local binary
pattern, gray-level co-occurrence matrix, gray-level run-length matrix), and a
gradient descriptor (histogram of oriented gradients).
RESULTS: The confusion matrix, averaged over all samples, showed 93.5% of muscle
pixels classified correctly. The classification, optimized in a leave-one-out
cross-validation, provided an average accuracy of 80% with a discrepancy in
overestimation for young (8%) and old (20%) dogs.
DISCUSSION: MPI could be useful for quantifying GRMD severity, but careful
interpretation is needed for severe cases. A significant percentage of Duchenne muscular dystrophy (DMD) cases are caused
by premature termination codon (PTC) mutations in the dystrophin gene, leading
to the production of a truncated, non-functional dystrophin polypeptide.
PTC-suppressing compounds (PTCSC) have been developed in order to restore
protein translation by allowing the incorporation of an amino acid in place of a
stop codon. However, limitations exist in terms of efficacy and toxicity. To
identify new compounds that have PTC-suppressing ability, we selected and
clustered existing PTCSC, allowing for the construction of a common
pharmacophore model. Machine learning (ML) and deep learning (DL) models were
developed for prediction of new PTCSC based on known compounds. We conducted a
search of the NCI compounds database using the pharmacophore-based model and a
search of the DrugBank database using pharmacophore-based, ML and DL models.
Sixteen drug compounds were selected as a consensus of pharmacophore-based, ML,
and DL searches. Our results suggest notable correspondence of the
pharmacophore-based, ML, and DL models in prediction of new PTC-suppressing
compounds. |
What is "long-COVID"? | "Long-COVID" is a complex condition where the affected individuals do not recover for several weeks or months following the onset of symptoms suggestive of COVID-19, and the symptoms are not explained by an alternative diagnosis.
Persistent physical symptoms following acute COVID-19 are common and typically include fatigue, dyspnea, chest pain, and cough. Headache, joint pain, myalgias, and loss of smell have also been reported. Common psychological and cognitive symptoms include poor concentration, cognitive impairment/confusion, insomnia, and overall reduced quality of life. | Large numbers of people are being discharged from hospital following COVID-19
without assessment of recovery. In 384 patients (mean age 59.9 years; 62% male)
followed a median 54 days post discharge, 53% reported persistent
breathlessness, 34% cough and 69% fatigue. 14.6% had depression. In those
discharged with elevated biomarkers, 30.1% and 9.5% had persistently elevated
d-dimer and C reactive protein, respectively. 38% of chest radiographs remained
abnormal with 9% deteriorating. Systematic follow-up after hospitalisation with
COVID-19 identifies the trajectory of physical and psychological symptom burden,
recovery of blood biomarkers and imaging which could be used to inform the need
for rehabilitation and/or further investigation. BACKGROUND AND AIMS: Long COVID is the collective term to denote persistence of
symptoms in those who have recovered from SARS-CoV-2 infection.
METHODS: WE searched the pubmed and scopus databases for original articles and
reviews. Based on the search result, in this review article we are analyzing
various aspects of Long COVID.
RESULTS: Fatigue, cough, chest tightness, breathlessness, palpitations, myalgia
and difficulty to focus are symptoms reported in long COVID. It could be related
to organ damage, post viral syndrome, post-critical care syndrome and others.
Clinical evaluation should focus on identifying the pathophysiology, followed by
appropriate remedial measures. In people with symptoms suggestive of long COVID
but without known history of previous SARS-CoV-2 infection, serology may help
confirm the diagnosis.
CONCLUSIONS: This review will helps the clinicians to manage various aspects of
Long COVID. Long COVID or post-COVID-19 syndrome first gained widespread recognition among
social support groups and later in scientific and medical communities. This
illness is poorly understood as it affects COVID-19 survivors at all levels of
disease severity, even younger adults, children, and those not hospitalized.
While the precise definition of long COVID may be lacking, the most common
symptoms reported in many studies are fatigue and dyspnoea that last for months
after acute COVID-19. Other persistent symptoms may include cognitive and mental
impairments, chest and joint pains, palpitations, myalgia, smell and taste
dysfunctions, cough, headache, and gastrointestinal and cardiac issues.
Presently, there is limited literature discussing the possible pathophysiology,
risk factors, and treatments in long COVID, which the current review aims to
address. In brief, long COVID may be driven by long-term tissue damage (e.g.
lung, brain, and heart) and pathological inflammation (e.g. from viral
persistence, immune dysregulation, and autoimmunity). The associated risk
factors may include female sex, more than five early symptoms, early dyspnoea,
prior psychiatric disorders, and specific biomarkers (e.g. D-dimer, CRP, and
lymphocyte count), although more research is required to substantiate such risk
factors. While preliminary evidence suggests that personalized rehabilitation
training may help certain long COVID cases, therapeutic drugs repurposed from
other similar conditions, such as myalgic encephalomyelitis or chronic fatigue
syndrome, postural orthostatic tachycardia syndrome, and mast cell activation
syndrome, also hold potential. In sum, this review hopes to provide the current
understanding of what is known about long COVID. COVID-19 is an ongoing pandemic with many challenges that are now extending to
its intriguing long-term sequel. 'Long-COVID-19' is a term given to the
lingering or protracted illness that patients of COVID-19 continue to experience
even in their post-recovery phase. It is also being called 'post-acute
COVID-19', 'ongoing symptomatic COVID-19', 'chronic COVID-19', 'post COVID-19
syndrome', and 'long-haul COVID-19'. Fatigue, dyspnea, cough, headache, brain
fog, anosmia, and dysgeusia are common symptoms seen in Long-COVID-19, but more
varied and debilitating injuries involving pulmonary, cardiovascular, cutaneous,
musculoskeletal and neuropsychiatric systems are also being reported. With the
data on Long-COVID-19 still emerging, the present review aims to highlight its
epidemiology, protean clinical manifestations, risk predictors, and management
strategies. With the re-emergence of new waves of SARS-CoV-2 infection,
Long-COVID-19 is expected to produce another public health crisis on the heels
of current pandemic. Thus, it becomes imperative to emphasize this condition and
disseminate its awareness to medical professionals, patients, the public, and
policymakers alike to prepare and augment health care facilities for continued
surveillance of these patients. Further research comprising cataloging of
symptoms, longer-ranging observational studies, and clinical trials are
necessary to evaluate long-term consequences of COVID-19, and it warrants
setting-up of dedicated, post-COVID care, multi-disciplinary clinics, and
rehabilitation centers. More than one year since its emergence, corona virus disease 2019 (COVID-19) is
still looming large with a paucity of treatment options. To add to this burden,
a sizeable subset of patients who have recovered from acute COVID-19 infection
have reported lingering symptoms, leading to significant disability and
impairment of their daily life activities. These patients are considered to
suffer from what has been termed as "chronic" or "long" COVID-19 or a form of
post-acute sequelae of COVID-19, and patients experiencing this syndrome have
been termed COVID-19 long-haulers. Despite recovery from infection, the
persistence of atypical chronic symptoms, including extreme fatigue, shortness
of breath, joint pains, brain fogs, anxiety and depression, that could last for
months implies an underlying disease pathology that persist beyond the acute
presentation of the disease. As opposed to the direct effects of the virus
itself, the immune response to severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2) is believed to be largely responsible for the appearance of these
lasting symptoms, possibly through facilitating an ongoing inflammatory process.
In this review, we hypothesize potential immunological mechanisms underlying
these persistent and prolonged effects, and describe the multi-organ long-term
manifestations of COVID-19. Our objective was to mine Reddit to discover long-COVID symptoms self-reported
by users, compare symptom distributions across studies, and create a symptom
lexicon. We retrieved posts from the /r/covidlonghaulers subreddit and extracted
symptoms via approximate matching using an expanded meta-lexicon. We mapped the
extracted symptoms to standard concept IDs, compared their distributions with
those reported in recent literature and analyzed their distributions over time.
From 42 995 posts by 4249 users, we identified 1744 users who expressed at least
1 symptom. The most frequently reported long-COVID symptoms were mental
health-related symptoms (55.2%), fatigue (51.2%), general ache/pain (48.4%),
brain fog/confusion (32.8%), and dyspnea (28.9%) among users reporting at least
1 symptom. Comparison with recent literature revealed a large variance in
reported symptoms across studies. Temporal analysis showed several persistent
symptoms up to 15 months after infection. The spectrum of symptoms identified
from Reddit may provide early insights about long-COVID. We aimed this systematic review to analyze and review the currently available
published literature related to long COVID, understanding its pattern, and
predicting the long-term effects on survivors. We thoroughly searched the
databases for relevant articles till May 2021. The research articles that met
our inclusion and exclusion criteria were assessed and reviewed by two
independent researchers. After preliminary screening of the identified articles
through title and abstract, 249 were selected. Consequently, 167 full-text
articles were assessed and reviewed based on our inclusion criteria and thus 20
articles were regarded as eligible and analyzed in the present analysis. All the
studies included adult population aged between 18 and above 60 years. The median
length of hospital stay of the COVID-19 patients during the acute infection
phase ranged from 8 days to 17 days. The most common prevalent long-term
symptoms in COVID-19 patients included persistent fatigue and dyspnea in almost
all of the studies. Other reported common symptoms included: shortness of
breath, cough, joint pain, chest pain or tightness, headache, loss of
smell/taste, sore throat, diarrhea, loss of memory, depression, anxiety.
Associated cardiovascular events included arrhythmias, palpitations and
hypotension, increased HR, venous thromboembolic diseases, myocarditis, and
acute/decompensated heart failure as well. Among neurological manifestations
headache, peripheral neuropathy symptoms, memory issues, concentration, and
sleep disorders were most commonly observed with varying frequencies. Mental
health issues affecting mental abilities, mood fluctuations namely anxiety and
depression, and sleep disorders were commonly seen. Further, diarrhea, vomiting,
digestive disorders, and Loss of appetite or weight loss are common
gastrointestinal manifestations. Therefore, appropriate clinical evaluation is
required in long COVID cases which in turn may help us to identify the risk
factors, etiology, and to my help, we treat them early with appropriate
management strategies. |
Are functional tests a good biomarker for Duchenne Muscular Dystrophy? | North Star Ambulatory Assessment is practical and reliable. allow assessment of high-functioning boys with Duchenne muscular dystrophy. | Eighteen boys with Duchenne muscular dystrophy (DMD) were assessed for their
ability to perform tasks involving wrist and hand function. Each subject was
assessed using the Jebsen Test of Hand Function, range of motion measurements,
and muscle strength tests. Writing and simulated page turning were performed
successfully by boys in all age groups. Boys over age 15 had difficulty
completing simulated feeding and picking up large and small objects. The muscle
strength of the wrist extensors and the radial deviation range of motion at the
wrist were found to be strongly correlated with six of the seven tasks assessed.
These two clinical assessments appear to be good indicators of overall wrist and
hand function. Life expectancy with DMD is increasing with advances in
respiratory care making preservation of wrist and hand function, the major
activity remaining with advanced disease, increasingly important. OBJECTIVE: To describe the involvement of lower leg muscles in boys with
Duchenne muscular dystrophy (DMD) by using MR imaging (MRI) and spectroscopy
(MRS) correlated to indices of functional status.
SUBJECTS AND METHODS: Nine boys with DMD (mean age, 11 years) and eight healthy
age- and BMI-matched boys (mean age, 13 years) prospectively underwent lower leg
MRI, 1H-MRS of tibialis anterior (TA) and soleus (SOL) for lipid fraction
measures, and 31P-MRS for pH and high-energy phosphate measures. DMD subjects
were evaluated using the Vignos lower extremity functional rating, and tests
including 6 min walk test (6MWT) and 10 m walk.
RESULTS: DMD subjects had highest fatty infiltration scores in peroneal muscles,
followed by medial gastrocnemius and soleus. Compared to controls, DMD boys
showed higher intramuscular fat (P = 0.04), lipid fractions of TA and SOL
(P = 0.02 and 0.003, respectively), pH of anterior compartment (P = 0.0003), and
lower phosphocreatine/inorganic phosphorus ratio of posterior compartment
(P = 0.02). The Vignos rating correlated with TA (r = 0.79, P = 0.01) and SOL
(r = 0.71, P = 0.03) lipid fractions. The 6MWT correlated with fatty
infiltration scores of SOL (r = -0.76, P = 0.046), medial (r = -0.80, P = 0.03)
and lateral (r = -0.84, P = 0.02) gastrocnemius, intramuscular fat (r = -0.80,
P = 0.03), and SOL lipid fraction (r = -0.89, P = 0.007). Time to walk 10 m
correlated with anterior compartment pH (r = 0.78, P = 0.04).
CONCLUSION: Lower leg muscles of boys with DMD show a distinct involvement
pattern and increased adiposity that correlates with functional status. Lower
leg MRI and 1H-MRS studies may help to noninvasively demonstrate the severity of
muscle involvement. BACKGROUND AND PURPOSE: The aims of this study were to develop a clinical
assessment scale to measure functional ability in ambulant boys with Duchenne
muscular dystrophy and to determine the reliability of the scale in multiple
centres in the UK.
METHODS: Focus groups and workshops were held with experienced paediatric
neuromuscular physiotherapists to determine scale content. A manual was prepared
with accompanying videos, and training sessions were conducted. A total of 17
physiotherapists from participating centres used the videos to determine
inter-rater reliability. Five determined the intra-rater reliability.
RESULTS: Strength of agreement for these groups based on total subject scores
was very good (0.95 and ≥ 0.93 for consistency and absolute agreement,
respectively). Test-retest ability was high, with perfect agreement between
occasions for all but two items of the scale.
CONCLUSIONS: Our study indicates that the North Star Ambulatory Assessment is
practical and reliable. It takes only 10 minutes to perform and incorporates
both universally used timed tests as well as levels of activities, which allow
assessment of high-functioning boys with Duchenne muscular dystrophy. OBJECTIVE: Evaluate muscle force and motor function in patients with Duchenne
muscular dystrophy (DMD) in a period of six months.
METHOD: Twenty children and adolescents with diagnosis of DMD were evaluated
trough: measurement of the strength of the flexors and extensors of the
shoulder, elbow, wrist, knee and ankle through the Medical Research Council
(MRC), and application of the Motor Function Measure (MFM). The patients were
evaluated twice within a six-month interval.
RESULTS: Loss of muscle strength was identified in the MRC score for upper
proximal members (t=-2.17, p=0.04). In the MFM, it was noted significant loss in
the dimension 1 (t=-3.06, p=0.006). Moderate and strong correlations were found
between the scores for muscular strength and the MFM dimensions.
CONCLUSION: The MFM scale was a useful instrument in the follow up of patients
with DMD. Moreover, it is a more comprehensive scale to assess patients and very
good for conducting trials to evaluate treatment. BACKGROUND: The aim of this study was to perform a longitudinal assessment using
Quantitative Muscle Testing (QMT) in a cohort of ambulant boys affected by
Duchenne muscular dystrophy (DMD) and to correlate the results of QMT with
functional measures. This study is to date the most thorough long-term
evaluation of QMT in a cohort of DMD patients correlated with other measures,
such as the North Star Ambulatory Assessment (NSAA) or three 6-min walk test
(6MWT).
METHODS: This is a single centre, prospective, non-randomised, study assessing
QMT using the Kin Com(®) 125 machine in a study cohort of 28 ambulant DMD boys,
aged 5 to 12 years. This cohort was assessed longitudinally over a 12 months
period of time with 3 monthly assessments for QMT and with assessment of
functional abilities, using the NSAA and the 6MWT at baseline and at 12 months
only. QMT was also used in a control group of 13 healthy age-matched boys
examined at baseline and at 12 months.
RESULTS: There was an increase in QMT over 12 months in boys below the age of
7.5 years while in boys above the age of 7.5 years, QMT showed a significant
decrease. All the average one-year changes were significantly different than
those experienced by healthy controls. We also found a good correlation between
quantitative tests and the other measures that was more obvious in the stronger
children.
CONCLUSION: Our longitudinal data using QMT in a cohort of DMD patients suggest
that this could be used as an additional tool to monitor changes, providing
additional information on segmental strength. PURPOSE: Duchenne muscular dystrophy can lead to upper extremity limitations,
pain and stiffness. In a previous study, these domains have been investigated
using extensive questionnaires, which are too time-consuming for clinical
practice. This study aimed at gaining insight into the underlying dimensions of
these questionnaires, and to construct a short questionnaire that can be used
for clinical assessment.
METHODS: Exploratory factor analysis was performed on the responses of 213
participants to a web-based survey to find the underlying dimensions in the
Capabilities of Upper Extremity questionnaire, the ABILHAND questionnaire, and
questionnaires regarding pain and stiffness. Based on these underlying
dimensions, a stepwise approach was formulated. In addition, construct validity
of the factors was investigated.
RESULTS: In total, 14 factors were identified. All had high internal consistency
(Cronbach's alpha >0.89) and explained 80-88% of the variance of the original
questionnaires. Construct validity was supported, because participants in the
early ambulatory stage performed significantly better (p< 0.001) than
participants in the late non-ambulatory stage.
CONCLUSION: The factors identified from the set of questionnaires provide a
valid representation of upper extremity function, pain and stiffness in Duchenne
muscular dystrophy. Based on the factor commonalities, the Upper Limb Short
Questionnaire was formulated. Implications for Rehabilitation New insights into
the underlying dimensions of upper extremity function, pain and stiffness in
Duchenne muscular dystrophy are gained. Fourteen factors, with good internal
consistency and construct validity, are identified regarding upper extremity
function, pain and stiffness in Duchenne muscular dystrophy. Based on these
factors, the Upper Limb Short Questionnaire is presented. The Upper Limb Short
Questionnaire can be used as an identifier of arm-hand limitations and the start
of more thorough clinical investigation. Becker muscular dystrophy (BMD) is a neuromuscular disorder allelic to Duchenne
muscular dystrophy (DMD), caused by in-frame mutations in the dystrophin gene,
and characterized by a clinical progression that is both milder and more
heterogeneous than DMD. Muscle magnetic resoce imaging (MRI) has been
proposed as biomarker of disease progression in dystrophinopathies. Correlation
with clinically meaningful outcome measures such as North Star Ambulatory
Assessment (NSAA) and 6 minute walk test (6MWT) is paramount for biomarker
qualification. In this study, 51 molecularly confirmed BMD patients (aged 7-69
years) underwent muscle MRI and were evaluated with functional measures (NSAA
and 6MWT) at the time of the MRI, and subsequently after one year. We confirmed
a pattern of fatty substitution involving mainly the hip extensors and most
thigh muscles. Severity of muscle fatty substitution was significantly
correlated with specific DMD mutations: in particular, patients with an isolated
deletion of exon 48, or deletions bordering exon 51, showed milder involvement.
Fat infiltration scores correlated with baseline functional measures, and
predicted changes after 1 year. We conclude that in BMD, skeletal muscle MRI not
only strongly correlates with motor function, but also helps in predicting
functional deterioration within a 12-month time frame. Author information:
(1)Division of Pediatric Neurology, University of Basel Children's Hospital,
Basel, Switzerland; Department of Neurology, University of Basel Hospital,
Basel, Switzerland.
(2)Division of Pediatric Neurology, University of Basel Children's Hospital,
Basel, Switzerland; Division of Neurology, Medical University Clinic,
Kantonsspital Baselland, Bruderholz, Switzerland.
(3)Division of Pediatric Neurology, University of Basel Children's Hospital,
Basel, Switzerland; Division of Pediatric Neurology, Lausanne University
Hospital, Lausanne, Switzerland; Division of Pediatric Neurology, University of
Berne Hospital, Berne, Switzerland.
(4)Division of Pediatric Neurology, University of Basel Children's Hospital,
Basel, Switzerland.
(5)Department of Pediatrics, Kaiser Franz Josef Hospital, Vienna, Austria.
(6)Laboratoire de Génétique Médicale, INSERM 1112, Faculté de Médecine,
Strasbourg, France.
(7)Division of Pediatric Neurology, Lausanne University Hospital, Lausanne,
Switzerland.
(8)Division of Pediatric Neurology, University of Berne Hospital, Berne,
Switzerland.
(9)Division of Pediatric Neurology, Children's Hospital, Aarau, Switzerland.
(10)Department of Radiology, Division of Radiological Physics, University of
Basel Hospital, Basel, Switzerland.
(11)Department of Clinical Research, Clinical Trial Unit, University of Basel
Hospital, Basel, Switzerland.
(12)Division of Pediatric Neurology, University of Basel Children's Hospital,
Basel, Switzerland; Department of Neurology, University of Basel Hospital,
Basel, Switzerland; Division of Neurology, Medical University Clinic,
Kantonsspital Baselland, Bruderholz, Switzerland. Electronic address:
[email protected]. OBJECTIVE: To investigate the effects of lower limb flexibility on the
functional performance of children with Duchenne muscular dystrophy.
METHODS: Thirty children, whose functional levels were at 1 or 2 according to
the Brooke Lower Extremity Functional Classification Scale, were included in
this study. The flexibilities of the hamstrings, hip flexors, tensor fascia
latae, and gastrocnemius muscles were evaluated in the children's domit lower
limbs. The children's functional performance was assessed using 6-minute walk
tests and timed performance tests. The correlations between the flexibilities of
the lower limb muscles and the performance tests were examined.
RESULTS: The flexibilities of the lower extremity muscles were found to be
correlated to the 6-minute walk tests and the timed performance tests. The
flexibility of the hamstrings (r = -.825), the gastrocnemius muscles (r = .545),
the hip flexors (r = .481), and the tensor fascia latae (r = .445) were found to
be correlated with functional performance as measured by the 6-minute walk tests
(P < .05).
DISCUSSION: The results of the current study indicate that the flexibility of
the lower limbs has an effect on functional performance in the early stages of
Duchenne muscular dystrophy. More research is needed to determine the functional
effects of flexibility on performance by adding long-term flexibility exercises
to the physiotherapy programs of children with Duchenne muscular dystrophy. While the number of new treatment options tested in patients with Duchenne
muscular dystrophy (DMD) is increasing, there is still no defining of the most
reliable assessments regarding therapeutic efficacy. We present clinical and
radiological outcome measures used in ambulatory patients participating in our
trial "Treatment with L-citrulline and metformin in Duchenne muscular
dystrophy". The motor function measure is a validated test in patients with
neuromuscular disorders that consists of 32 items and assesses all three
dimensions of motor performance including standing and transfer (D1 subscore),
axial and proximal motor function (D2 subscore), and distal motor function (D3
subscore). The test shows high intra- and inter-rater variability but only when
strictly following guidelines of the materials, examination steps, and
calculation of scores. The 6-minute walk test, timed 10-meter walk/run test, and
supine-up time are commonly used timed functional tests that also sufficiently
monitor changes in muscle function; however, they strongly depend on patient
collaboration. Quantitative MRI is an objective and sensitive biomarker to
detect subclinical changes, though the examination costs may be a reason for its
limited use. In this study, a high correlation between all clinical assessments
and quantitative MRI scans was found. The combinational use of these methods
provides a better understanding about disease progression; however, longitudinal
studies are needed to validate their reliability. OBJECTIVE: Duchenne muscular dystrophy, an X-linked genetic disease, leads to
progressive muscle weakness mainly in the lower limbs. Motor function tests help
to monitor disease progression. Can low-cost, simple assessments help in the
diagnostic suspicion of Duchenne muscular dystrophy? The authors aim to define
the sensitivity of time to rise from the floor, time to walk 10meters, and time
to run 10meters, evaluating them as eventual diagnostic screening tools.
METHODS: This is an analytical, observational, retrospective (1998-2015), and
prospective study (2015-2018). Cases were recruited from the database of the
pediatric neurology department and the healthy, from child care consultations,
with normal gait development (up to 15 months) and without other comorbidities
(neuromuscular, pulmonary, heart diseases) from the same university hospital.
RESULTS: 128 Duchenne muscular dystrophy patients and 344 healthy children were
analyzed, equally distributed in age groups. In Duchenne muscular dystrophy,
there is a progressive increase in the means of the times to perform the motor
tests according to the age group, which accelerates very abruptly after 7 years
of age. Healthy children acquire maximum motor capacity at 6 years and stabilize
their times. The time to rise showed a p-value <0.05 and a strong association
(effect size [ES] >0.8) in all age groups (except at 12 years), with time to
walk 10 meters from 9 years, and with time to run 10 meters , from 5 years. The
100% sensitivity points were defined as follows: time to rise, at 2s; time to
walk 10 meters, 5s; time to run 10 meters, 4s.
CONCLUSIONS: Time to rise is a useful and simple tool in the screening of
neuromuscular disorders such as Duchenne muscular dystrophy, a previously
incurable disease with new perspectives for treatment. Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder
caused by out of frame mutations in the dystrophin gene. The hallmark symptoms
of the condition include progressive degeneration of skeletal muscle,
cardiomyopathy, and respiratory dysfunction. The most recent advances in
therapeutic strategies for the treatment of DMD involve exon skipping or
administration of minidystrophin, but these strategies are not yet universally
available, nor have they proven to be a definitive cure for all DMD patients.
Early diagnosis and tracking of symptom progression of DMD usually relies on
creatine kinase tests, evaluation of patient performance in various ambulatory
assessments, and detection of dystrophin from muscle biopsies, which are
invasive and painful for the patient. While the current research focuses
primarily on restoring functional dystrophin, accurate and minimally invasive
methods to detect and track both symptom progression and the success of early
DMD treatments are not yet available. In recent years, several groups have
identified miRNA signature changes in DMD tissue samples, and a number of
promising studies consistently detected changes in circulating miRNAs in blood
samples of DMD patients. These results could potentially lead to non-invasive
detection methods, new molecular approaches to treating DMD symptoms, and new
methods to monitor of the efficacy of the therapy. In this review, we focus on
the role of circulating miRNAs in DMD and highlight their potential both as a
biomarker in the early detection of disease and as a therapeutic target in the
prevention and treatment of DMD symptoms. As the drug development pipeline for Duchenne muscular dystrophy (DMD) rapidly
advances, clinical trial outcomes need to be optimized. Effective assessment of
disease burden, natural history progression, and response to therapy in clinical
trials for Duchenne muscular dystrophy are critical factors for clinical trial
success. By choosing optimal biomarkers to better assess therapeutic efficacy,
study costs and sample size requirements can be reduced. Currently, functional
measures continue to serve as the primary outcome for the majority of DMD
clinical trials. Quantitative measures of muscle health, including magnetic
resoce imaging and spectroscopy, electrical impedance myography, and
ultrasound, sensitively identify diseased muscle, disease progression, and
response to a therapeutic intervention. Furthermore, such non-invasive
techniques have the potential to identify disease pathology prior to onset of
clinical symptoms. Despite robust supportive evidence, non-invasive quantitative
techniques are still not frequently utilized in clinical trials for Duchenne
muscular dystrophy. Non-invasive quantitative techniques have demonstrated the
ability to quantify disease progression and potential response to therapeutic
intervention, and should be used as a supplement to current standard functional
measures. Such methods have the potential to significantly accelerate the
development and approval of therapies for DMD. Duchenne muscular dystrophy (DMD) usually affects men. However, women are also
affected in rare instances. Approximately 8% of female DMD carriers have muscle
weakness and cardiomyopathy. The early identification of functional and motor
impairments can support clinical decision making.
OBJECTIVE: To investigate the motor and functional impairments of 10 female
patients with dystrophinopathy diagnosed with clinical, pathological, genetic
and immunohistochemical studies.
METHODS: A descriptive study of a sample of symptomatic female carriers of DMD
mutations. The studied variables were muscular strength and functional
performance.
RESULTS: The prevalence was 10/118 (8.4%) symptomatic female carriers. Deletions
were found in seven patients. The age of onset of symptoms in female carriers of
DMD was quite variable. Pseudohypertrophy of calf muscles, muscular weakness,
compensatory movements and longer timed performance on functional tasks were
observed in most of the cases. Differently from males with DMD, seven female
patients showed asymmetrical muscular weakness. The asymmetric presentation of
muscle weakness was frequent and affected posture and functionality in some
cases. The functional performance presents greater number of compensatory
movements. Time of execution of activities was not a good biomarker of
functionality for this population, because it does not change in the same
proportion as the number of movement compensations.
CONCLUSION: Clinical manifestation of asymmetrical muscle weakness and
compensatory movements, or both can be found in female carriers of DMD
mutations, which can adversely affect posture and functional performance of
these patients. BACKGROUND: Duchenne Muscular Dystrophy is a severe, incurable disorder caused
by mutations in the dystrophin gene. The disease is characterized by decreased
muscle function, impaired muscle regeneration and increased inflammation. In a
clinical context, muscle deterioration, is evaluated using physical tests and
analysis of muscle biopsies, which fail to accurately monitor the disease
progression.
OBJECTIVES: This study aims to confirm and asses the value of blood protein
biomarkers as disease progression markers using one of the largest longitudinal
collection of samples.
METHODS: A total of 560 samples, both serum and plasma, collected at three
clinical sites are analyzed using a suspension bead array platform to assess 118
proteins targeted by 250 antibodies in microliter amount of samples.
RESULTS: Nine proteins are confirmed as disease progression biomarkers in both
plasma and serum. Abundance of these biomarkers decreases as the disease
progresses but follows different trajectories. While carbonic anhydrase 3,
microtubule associated protein 4 and collagen type I alpha 1 chain decline
rather constantly over time, myosin light chain 3, electron transfer
flavoprotein A, troponin T, malate dehydrogenase 2, lactate dehydrogenase B and
nestin plateaus in early teens. Electron transfer flavoprotein A, correlates
with the outcome of 6-minutes-walking-test whereas malate dehydrogenase 2
together with myosin light chain 3, carbonic anhydrase 3 and nestin correlate
with respiratory capacity.
CONCLUSIONS: Nine biomarkers have been identified that correlate with disease
milestones, functional tests and respiratory capacity. Together these biomarkers
recapitulate different stages of the disorder that, if validated can improve
disease progression monitoring. Aim: Using baseline data from a clinical trial of domagrozumab in Duchenne
muscular dystrophy, we evaluated the correlation between functional measures and
quantitative MRI assessments of thigh muscle. Patients & methods: Analysis
included timed functional tests, knee extension/strength and North
Star Ambulatory Assessment. Patients (n = 120) underwent examinations of one
thigh, with MRI sequences to enable measurements of muscle volume (MV), MV
index, mean T2 relaxation time via T2-mapping and fat fraction. Results: MV was
moderately correlated with strength assessments. MV index, fat fraction and
T2-mapping measures had moderate correlations (r ∼ 0.5) to all functional tests,
North Star Ambulatory Assessment and age. Conclusion: The moderate correlation
between functional tests, age and baseline MRI measures supports MRI as a
biomarker in Duchenne muscular dystrophy clinical trials. Trial registration:
ClinicalTrials.gov, NCT02310763; registered 4 November 2014. |
What is the most sensitive test for the diagnosis of multiple sclerosis? | These results support previous conclusions that MRI is the most sensitive test for detecting white matter asymptomatic lesions, and the most predictive for the diagnosis of CDMS. | The relation between the results of 7 biological markers (cells, total protein,
albumin, IgG, IgG ratio, Tibbling ratio, and Tourtellotte's formula) and 4
paraclinical tests (PEV, PEATC, CT and MR) in 236 patients with multiple
sclerosis (MS) not selected by the localization of symptoms were studied. One
hundred forty-one had clinically defined MS, 22 had defined MS supported by a
laboratory and 68 had clinically probable MS. The existence of a relation
between PEV and MRI abnormality and the increase in the concentration and the
ratios of intrathecal IgG synthesis and the degree of certainty of disease
diagnosis was demonstrated. The most sensitive test was MRI (93%) followed by
VEP (83%) and BAEP (60%) and the sensitivity of the study with high resolution
CT including 59 patients explored by double enhancement and delayed cut off was
very low (33%). It was considered that for the lack of a specific diagnostic
test the use of biological markers PEV and MR constituted a necessary aid in the
diagnosis of MS. Magnetic resoce imaging (MRI) has recently been recognised as the most
sensitive method with which to detect clinically silent lesions in patients
affected by multiple sclerosis. Visually guided horizontal saccadic eye
movements (SEM) were studied, together with MRI, in 57 multiple sclerosis
patients. A very similar sensitivity was found for both MRI (78.2%) and SEM
analysis (76.3%). Significant associations between peak saccadic velocity and
brain stem signs and between saccadic latency and visual signs were observed. Magnetic resoce imaging (MRI) has been shown to be a good method of
visualizing the lesions in MS. We have studied several applications of MRI to
the evaluation of patients and experimental models. In diagnosis, MRI is the
most sensitive test for the demonstration of dissemination of lesions in space.
Pathological correlation studies show that MRI reliably measures the extent of
chronic demyelination. Experimental studies show that MRI detects acute
inflammatory lesions and measures their evolution. MRI also is a reliable
measure of the extent of the MS process, serial MRI scans detect evidence of
disease activity in MS not always disclosed by clinical evaluation. MRI will
have an enormous future impact on the evaluation of patients in clinical studies
and in understanding the evolution of pathological processes. The results of cerebrospinal fluid agarose gel electrophoresis in 300
consecutive patients were correlated with neurological examinations and
diagnoses, other cerebrospinal fluid studies, and the results of evoked
potential examinations. The presence of oligoclonal bands was the most sensitive
test for multiple sclerosis (MS); bands were present in from 100% (11/11) of
patients with definite MS to 82% (27/33) of those with possible MS (classified
by McAlpine criteria). The visual evoked response was the next most sensitive
study. Thirty-eight patients without MS or related disorders had bands in the
IgG region. Three patients had plasma cell dyscrasias. Seven patients had thick
single bands. Single bands did not correlate with chronic polyneuropathy but
appeared to be an artifact of storage. Twenty-eight patients had active
neurological disease, including cerebral infarction (in 5), viral infection (in
4), remote effect of carcinoma (in 4), and acute and chronic polyneuropathies
(in 6). In acute illnesses (i.e., vascular insults), repeat electrophoresis
showed disappearance of bands. In continually active disease, bands persisted.
These results indicate that the presence of oligoclonal bands provides sensitive
supporting evidence for the diagnosis of MS but that bands may be present in
other disorders, including those not directly related to infection or abnormal
immune response. The data suggest that oligoclonal bands may represent an immune
response to neurological injury that is prominent in disorders with a
particularly intense or continuous antigenic stimulus. The yield of paraclinical tests was evaluated in a prospective study of 189
consecutive patients referred for suspected multiple sclerosis (142 patients
with multiple sclerosis, 47 non-multiple sclerosis patients on discharge).
Patients were first classified according to the Poser criteria by the clinical
findings. Subsequently, the results of paraclinical tests (cranial MRI, visually
evoked potentials (VEPs), somatosensory evoked potentials by tibial nerve
stimulation (SSEPs), motor evoked potentials (MEPs), and analysis of CSF for
oligoclonal banding and IgG-index (CSF)) were taken into account. The percentage
of reclassified patients (reclassification sensitivity, RS) was always lower
than the percentage of abnormal results (diagnostic sensitivity, DS), and the
divergence of RS v DS differed between the tests (60% v 84% in MRI, 31% v 77% in
CSF, 29% v 37% in VEPs, 20% v 68% in MEPs, and 12% v 46% in SSEPs respectively).
False reclassifications of non-multiple sclerosis patients to multiple sclerosis
would have occurred with all tests (MRI: six of 47 patients, (reclassification
specificity 88%); CSF: one (98%); VEPs: two (96%); MEPs: two (96%); SSEPs: four
(91%); P < 0.05). Although MRI had superior diagnostic capacity, 57 of the 142
patients with multiple sclerosis were not reclassified by the MRI result, 12 of
whom were reclassified by CSF and 18 by one of the evoked potential (EP)
studies. Of the 98 patients not reclassified by CSF, 53 were reclassified by MRI
and 39 by EPs. The results suggest that for the evaluation of paraclinical tests
in suspected multiple sclerosis, comparison of diagnostic sensitivities is
inappropriate. In general, a cranial MRI contributes most to the diagnosis;
however, due to its comparatively low specificity and its considerable number of
negative results, EP or CSF studies are often useful to establish the diagnosis
of multiple sclerosis. The sensitivities and predictive values of visual, somatosensory, and brain
auditory evoked potentials (EPs), cerebrospinal fluid oligoclonal banding
(CSF-OB) and magnetic resoce imaging (MRI) were evaluated for the early
diagnosis of clinically definite multiple sclerosis (CDMS). Paraclinical
evidence of asymptomatic lesions allows a diagnosis of CDMS. Eighty-two patients
in whom MS was suspected but diagnosis of CDMS was not possible entered the
study prospectively. Paraclinical examinations were performed at entry. Patients
were examined and underwent EPs every 6 months, and MRI yearly. After a mean
follow-up of 2.9 years, 28 patients (34%) had developed CDMS (McDonald-Halliday
criteria). The initial MRI was strongly suggestive of MS in 19 of these (68%),
while 27 (96%) had at least one MS-like abnormality in the initial MRI. CSF-OB
and EPs had lower sensitivities. CDMS developed during follow-up in 19 of the 36
patients (53%) who had an initial MRI strongly suggestive of MS but in only 1 of
the 25 who had normal MRI when first studied. These results support previous
conclusions that MRI is the most sensitive test for detecting white matter
asymptomatic lesions, and the most predictive for the diagnosis of CDMS. Magnetic resoce is the most sensitive para-clinical method available for the
diagnosis of multiple sclerosis since it shows changes in 95% of the patients
with clinically definite multiple sclerosis. However, little correlation has
been found, in different studies, between the parameters of magnetic resoce
and the degree of neurological disability. The development and gradual
application of new techniques of magnetic resoce, which permit specific
detection of the lesions with the greatest degree of nerve dysfunction, permits
improvement in the use of this technique for study of the natural history of the
disease and thus to monitor patients given new treatments. There is no single test that is diagnostic of MS, including MRI. The lesions
detected with MRI are pathologically nonspecific. The principles of MS diagnosis
are based on showing dissemination of white matter lesions in space and time.
MRI is the most sensitive method for revealing asymptomatic dissemination of
lesions in space and time. The pattern and evolution of MRI lesions, in the
appropriate clinical setting, has made MRI abnormalities invaluable criteria for
the early diagnosis of MS. The first important role for MRI in the diagnosis of
MS allows for an early diagnosis of MS for CIS patients using the IP diagnostic
criteria, including MRI for dissemination in space (DIS) and time (DIT). The
sensitivity of diagnosing MS within the first year after a single attack is 94%,
with a specificity of 83%. The MRI evidence required to support the diagnosis
varies, depending on the strength of the clinical findings. Allowing a new MRI
lesion to substitute for a clinical attack doubles the number of CIS patients
who can be diagnosed as having MS within 1 year of symptom onset. Increasing the
sensitivity of the test with more lenient criteria, as recommended by the AAN
subcommittee, can result in decreased specificity. The second important role for
MRI in the diagnostic work-up of suspected MS patients is to rule out
alternative diagnoses obvious on MRI, such as spinal stenosis and most brain
tumors. Characteristic lesions that favor MS include Dawson Fingers, ovoid
lesions, corpus callosum lesions, and asymptomatic spinal cord lesions. However,
other white matter diseases can have similar appearances on MRI. Persistent
gadolinium enhancement greater than three months, lesions with mass effect, and
meningeal enhancement suggest other disorders. A standardized MRI protocol for
brain and spinal cord is crucial for comparing across studies or between
centers. T2W MRI cannot distinguish between acute and chronic lesions.
Gadolinium provides useful information about new lesion activity and is helpful
in ruling out alternative diagnoses such as neoplasm, vascular malformations,
and leptomeningeal disease. A single gadolinium-enhanced MRI can potentially
provide evidence for dissemination in space and time. Spinal cord imaging is
equally valuable to rule out spinal stenosis or tumor, and for detecting
asymptomatic lesions when brain imaging is nondiagnostic in patients suspected
of having MS. Precise criteria may be too suggestive that MS can be diagnosed by
MRI and a negative MRI at the time of CIS does not rule out MS. MRI evidence
plays a supportive role in what is ultimately a clinical diagnosis of MS, in the
appropriate clinical situation, and always at the exclusion of alternative
diagnoses. Magnetic resoce imaging (MRI) is a sensitive paraclinical test for diagnosis
and assessment of disease progression in multiple sclerosis (MS) and is often
used to evaluate therapeutic efficacy. The formation of new T2-hyperintense MRI
lesions is commonly used to measure disease activity, but lacks specificity
because edema, inflammation, gliosis, and axonal loss all contribute to T2
lesion formation. As the role of neurodegeneration in the pathophysiology of MS
has become more prominent, the formation and evolution of chronic or persistent
Tl-hypointense lesions (black holes) have been used as markers of axonal loss
and neuronal destruction to measure disease activity. Despite the use of various
detection methods, including advanced imaging techniques such as magnetization
transfer imaging and magnetic resoce spectroscopy, correlation of persistent
black holes with clinical outcomes in patients with MS remains uncertain.
Furthermore, although axonal loss and neuronal tissue destruction are known to
contribute to irreversible disability in patients with MS, there are limited
data on the effect of therapy on longitudinal change in Tl-hypointense lesion
volume. Measurement of black holes in clinical studies may elucidate the
underlying pathophysiology of MS and may be an additional method of evaluating
therapeutic efficacy. |
Define pseudotumor cerebri. How is it treated? | Benign intracranial hypertension (BIH) is characterized by an elevation of the intracranial pressure not associated with an intracranial process or hydrocephaly, and with normal cerebrospinal fluid (CSF) contents. The elevation of the intracranial pressure is isolated; therefore, diseases such as cerebral venous thrombosis or dural fistulas should not be considered as etiologies of BIH. The exact definition of BIH remains debated, and other terms such as "pseudotumor cerebri" or "idiopathic intracranial hypertension" are often used in the literature. The management of patients with BIH depends mainly on the presence and severity of ocular symptoms and signs on which the prognostic of the disease is based. Repeated lumbar punctures associated with acetazolamide and weight loss are usually efficient enough. However a surgical treatment (optic nerve sheath fenestration or lumboperitoneal shunt) is required when appropriate medical management does not prevent progressive alteration of vision (visual loss or visual field defect), or when the patients complains of severe, refractory headaches. Careful follow-up with repeated formal visual field testing may help preventing a devastating visual loss in these patients. | Pseudotumor cerebri is a central nervous disorder with elevated intracranial
pressure that is most common among young obese women. It presents with headache,
transient visual obscurations and loss of central vision. Papilledema and visual
field defects are frequent. Acetazolamid can be used for treatment. If medical
treatment is not successful, optic nerve sheath decompression is recommended.
Three patients were treated medically and there were treated surgically. Both
methods stabilized or improved visual fields and central vision. Pseudotumour cerebri is the name of a syndrome characterized by headache and
papilloedema, with normal cerebral CT/MR studies and CSF with a high pressure
and normal laboratory findings. We describe four patients who fulfilled the
diagnostic criteria of this condition (including normal 0.5T MR studies). They
all had cerebral angiograms showing minor abnormalities localized to the level
of the superior longitudinal sinus. All improved on treatment with
anticoagulants and steroids. In view of these findings we consider that in cases
of pseudotumour cerebri without a clear aetiological factor, an angio MR study
should be done, or if this technique is not available, a cerebral angiogram
should be done, to exclude cerebral venous drainage defects. Pseudotumor cerebri is an unusual syndrome of increased intracranial pressure
without a space-occupying mass. Many associations are known, but the
pathogenesis remains a mystery. The diagnosis and treatment of pseudotumor
cerebri are often challenging. Because it is not rare, neurosurgeons,
neurologists, and ophthalmologists frequently work in concert to manage these
patients. This article reviews the diagnostic criteria and differential
diagnosis of pseudotumor cerebri. The medical and surgical treatments currently
employed in this disorder are discussed. PURPOSE: Demographic and outcome data in the era of modern neuroimaging are
needed to describe pseudotumor cerebri in children.
METHODS: We reviewed the medical records of children less than 18 years old who
were diagnosed with pseudotumor cerebri between 1977 and 1997. We defined
pseudotumor cerebri as (1) increased intracranial pressure, (2) normal or small
ventricles, and (3) normal cerebrospinal fluid composition. The condition might
be idiopathic or the result of a nontumor etiology.
RESULTS: Thirty-seven patients had an initial diagnosis of pseudotumor cerebri.
Two patients were subsequently diagnosed with a central nervous system
maligcy and were excluded from further analysis. The remaining 35 patients
included 10 patients with idiopathic pseudotumor cerebri and 25 patients with
disorders reported to be associated with pseudotumor cerebri. The mean age was
10.6 years with a range of 3 to 17 years. Twenty patients (57%) were female and
13 patients (37%) were obese. At presentation 4 patients had a visual acuity
less than 20/40 in the best eye and 10 patients had visual field deficits.
Seventeen patients (49%) had cranial nerve deficits, all of which resolved with
normalization of the intracranial pressure. Follow-up data were obtained on 30
patients. Only one patient had a final visual acuity less than 20/40 in the best
eye, whereas six patients had residual visual field deficits. Ten patients (33%)
had optic nerve atrophy.
CONCLUSIONS: There was no gender predomice, and associated etiologic factors
were common in these children with pseudotumor cerebri. Permanent visual loss
occurs in some children with pseudotumor cerebri. Quantitative perimetry and
optic nerve examination were more sensitive than visual acuity determination in
detecting damage to the visual sensory system. In rare instances the patient
diagnosed with pseudotumor cerebri will be found after extended follow-up to
harbor an intracranial neoplasm. Pseudotumor cerebri or benign intracranial hypertension is a syndrome of raised
intracranial pressure without obvious explanation. Most patients are obese women
at childbearing age. Symptoms and signs usually include headache, nausea,
vomiting, edema of the papilla, visual obscurations and rarely palsy of the
nervus abducens. The prognosis is generally good, but progressive visual loss
and eventual blindness are major risks. We report the case of a 21-year-old
non-obese young woman who developed pseudotumor cerebri while taking minocycline
for acne therapy. Identical symptoms occurred upon inadvert rechallenge with
minocycline for the second time. Pseudotumor cerebri is an idiopathic disorder characterized by papilledema and
elevated intracranial pressure without a mass lesion. Most patients are female
and young and are either overweight or have a history of recent weight gain.
Other disease states, such as systemic lupus erythematosus, and drugs, such as
tetracycline, have also been associated with the development of pseudotumor
cerebri. The mechanism is unclear, but is likely related to decreased
cerebrospinal fluid (CSF) resorption. Almost all patients have headache, but the
greatest morbidity of the disorder is visual loss related to optic disc
swelling. Common radiographic findings in pseudotumor cerebri include an empty
sella, dilation of the optic nerve sheaths and elevation of the optic disc. The
CSF, aside from elevated opening pressure, is normal without evidence of
infection or inflammation. Treatment of patients with no or mild to moderate
visual loss is primarily medical, with acetazolamide as the first-line agent.
Acetazolamide decreases CSF production. Furosemide and corticosteroids are
secondary choices. Optic nerve surgery is reserved for patients with severe
visual loss or progression in visual deficits despite medical management. Pseudotumor cerebri is a clinical syndrome characterized by raised intracranial
pressure with normal ventricular size, anatomy and position. Headache, vomiting
and diplopia are the most common symptoms. Signs include those of raised
intracranial pressure including papilledema and absence of focal neurological
signs. A secondary cause is identifiable in 50% of children; the most common
predisposing conditions are otitis media, viral infection and medications.
Management is mainly directed towards identifying and treating the cause and
measures to reduce the raised intracranial pressure. Though it is mostly a self
limited condition, optic atrophy and blindness can occur. Oculomotor nerve palsy
is very rarely associated with pseudotumor cerebri. We report a unique case of
pseudotumor cerebri who had left Oculomotor palsy with sparing of the pupillary
fibres, which resolved following treatment with oral acetazolamide. INTRODUCTION: Pseudotumor cerebri is a condition characterized by raised
intracranial pressure, normal CSF contents, and normal brain with normal or
small ventricles on imaging studies. It affects predomitly obese women of
childbearing age; however, its incidence seems to be increasing among adolescent
and children. While among older children the clinical picture is similar to that
of adults, younger children present demographic and clinical peculiarities.
Different diagnostic criteria for adults and pre-pubertal children have been
proposed. Etiology and pathogenesis are still unclear, particular concerning the
role of obstruction to venous outflow.
METHODS: An extensive literature review concerning all the aspects of
pseudotumor cerebri has been performed, both among adults and pre-pubertal
children.
CONCLUSION: Pseudotumor cerebri is an avoidable cause of visual loss, both in
adults and children. Few diagnostic measures are usually sufficient to determine
the correct diagnosis. Since pseudotumor cerebri is a diagnosis of exclusion,
the differential diagnosis work out is of special importance. Modern
neuroimaging techniques, especially magnetic resoce imaging and magnetic
resoce venography may clarify the role of obstruction to venous outflow in
each case. Various therapeutic options are available: medical, surgical, and
endovascular procedures may be used to prevent irreversible visual loss.
Treatment is usually effective, and most patients will experience complete
resolution of symptoms without persistent deficits. Idiopathic intracranial hypertension (IIH, pseudotumor cerebri) is a syndrome of
elevated intracranial pressure of unknown cause that occurs predomitly in
obese women of childbearing age. It is a diagnosis of exclusion and, therefore,
other causes of increased intracranial pressure must be sought with history,
imaging, and cerebrospinal fluid examination before the diagnosis can be made.
IIH produces symptoms and signs of increased intracranial pressure, including
papilledema. If untreated, papilledema can cause progressive irreversible visual
loss and optic atrophy. The treatment approach depends on the severity and time
course of symptoms and visual loss, as determined by formal visual field
testing. The main goals of treatment are alleviation of symptoms, including
headache, and preservation of vision. All overweight IIH patients should be
encouraged to enter a weight-management program with a goal of 5-10 % weight
loss, along with a low-salt diet. When there is mild visual loss, medical
treatment with acetazolamide should be initiated. Other medical treatments can
be added or substituted when acetazolamide is insufficient as monotherapy or
poorly tolerated. When visual loss is more severe or rapidly progressive,
surgical interventions, such as optic nerve sheath fenestration or cerebrospinal
fluid shunting, may be required to prevent further irreversible visual loss. The
choice of intervention depends on the relative severity of symptoms and visual
loss, as well as local expertise. At present, the role of transverse venous
sinus stenting remains unclear. Although there are no evidence-based data to
guide therapy, there is an ongoing randomized double-blind placebo-controlled
treatment trial, investigating diet and acetazolamide therapy for IIH. Pseudotumor cerebri, or benign intracranial hypertension, is characterized by
intracranial hypertension of unknown etiology typically in obese women <45 years
of age, and can be disabling secondary to headaches and visual disturbances.
Medical management includes pharmaceuticals that reduce cerebrospinal fluid
(CSF) production and lumbar punctures that reduce the CSF volume, both aimed at
reducing intracranial pressure. When medical management fails, surgical CSF
diverting procedures are indicated. Recently it has been demonstrated that dural
sinus stenosis or thrombosis can be responsible for this disease and treated
with endovascular venous stent placement. The intent of this educational
manuscript is to review the clinical presentation of pseudotumor cerebri
patients and discuss the medical, surgical, and endovascular treatment options
for this disease. After reading this paper, the reader should be able to: (1)
understand the pathophysiological basis of pseudotumor cerebri, (2) describe its
presenting signs and symptoms, and (3) discuss the medical, surgical, and
endovascular treatment options. AIMS: The aim was to identify Pseudotumor cerebri treatment options and assess
their efficacy.
SETTING AND DESIGN: Review article.
MATERIALS AND METHODS: Existing literature and the authors' experience were
reviewed.
RESULTS: Treatment options range from observation to surgical intervention.
Weight loss and medical treatment may be utilized in cases without vision loss
or in combination with surgical treatment. Cerebrospinal fluid shunting
procedures and/or optic nerve sheath decompression is indicated for severe
vision loss or headache unresponsive to medical management. The recent use of
endovascular stenting of transverse sinus stenoses has also demonstrated benefit
in patients with pseudotumor cerebri.
CONCLUSION: While each treatment form may be successful individually, a
multimodal approach is typically utilized with treatments selected on a
case-by-case basis. OBJECTIVE Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is
a complex and difficult-to-manage condition that can lead to permanent vision
loss and refractory headaches if untreated. Traditional treatment options, such
as unilateral ventriculoperitoneal (VP) or lumboperitoneal (LP) shunt placement,
have high complication and failure rates and often require multiple revisions.
The use of bilateral proximal catheters has been hypothesized as a method to
improve shunt survival. The use of stereotactic technology has improved the
accuracy of catheter placement and may improve treatment of IIH, with fewer
complications and greater shunt patency time. METHODS The authors performed a
retrospective chart review for all patients with IIH who underwent stereotactic
placement of biventriculoperitoneal (BVP) shunt catheters from 2008 to 2016 at
their institution. Bilateral proximal catheters were Y-connected to a Strata
valve with a single distal catheter. We evaluated clinical, surgical, and
ophthalmological variables and outcomes. RESULTS Most patients in this series of
34 patients (mean age 34.4 ± 8.2 years, mean body mass index 38.7 ± 8.3 kg/m2;
91.2% were women) undergoing 41 shunt procedures presented with headache (94.1%)
and visual deficits (85.3%). The mean opening pressure was 39.6 ± 9.0 cm H2O. In
addition, 50.0% had undergone previous unilateral shunt placement, and 20.6% had
undergone prior optic nerve sheath fenestration. After BVP shunt placement,
there were no cases of proximal catheter obstruction and only a single case of
valve obstruction at 41.9 months, with a mean follow-up of 24.8 ± 20.0 months.
Most patients showed improvement in their headache (82.4%), subjective vision
(70.6%), and papilledema (61.5% preoperatively vs 20.0% postoperatively, p =
0.02) at follow-up. Additional primary complications included 4 patients with
migration of their distal catheters out of the peritoneum (twice in 1 patient),
and an infection of the distal catheter after catheter dislodgment. The proximal
obstructive shunt complication rate in this series (2.9%) was lower than that
with LP (53.5%) or unilateral VP (37.8%) shunts seen in the literature.
CONCLUSIONS This small series suggests that stereotactic placement of BVP shunt
catheters appears to improve shunt survival rates and presenting symptoms in
patients with IIH. Compared with unilateral VP or LP shunts, the use of BVP
shunts may be a more effective and more functionally sustained method for the
treatment of IIH. Pseudotumor cerebri, or idiopathic intracranial hypertension (IIH), is a
syndrome of elevated intracranial pressure (ICP) of unknown etiology that occurs
predomitly in obese women of childbearing age. Pseudotumor cerebri literally
means "false brain tumor". It is a "diagnosis of exclusion" therefore a complete
work-up to rule out life-threatening causes for increased ICP must be performed
through a comprehensive history, complete physical examination, diagnostic
imaging, and cerebrospinal fluid (CSF) analysis before the diagnosis can be
made. The authors present the case of a young woman with headache, and near
blindness due to pseudotumor cerebri. The presentation, diagnosis, and treatment
options are discussed. |
What is pseudodementia? | Depression can cause some clinical symptoms and signs of dementia, classically in older adults. This type of "dementia" is called pseudodementia and is typically reversible with treatment. | Pseudodementia is the syndrome in which dementia is mimicked or caricatured by
functional psychiatric disorders. The author describes 10 patients with
pseudodementia and compares its clinical features with those of true dementia.
The syndrome occurred in patients with various psychiatric diagnoses, but a
striking feature in most patients was marked dependency. The recognition of this
clinical syndrome should obviate the need for many neurological diagnostic
studies and lead to earlier and more effective psychiatric treatment. Despite the increased attention that the syndrome of pseudodementia is
receiving, several important questions regarding diagnostic criteria and
accuracy, etiology, and even the appropriateness of the term itself remain
uswered. The author reviews the literature on this topic, including published
case reports. On the basis of the available data, it appears that there may be
at least two categories of pseudodementia and that the cognitive impairment
associated with depressive illness is more appropriately viewed as a
depression-induced organic mental disorder. Directions for future research are
suggested. BACKGROUND: The literature was reviewed to abstract items which were claimed to
distinguish organic dementia from pseudodementia. Their discriminating powers
were tested in a prospective study. Eighteen of these items were selected to
create a questionnaire which should distinguish organic dementia from
pseudodementia. The gold standard was the final diagnosis given by a consultant
psychiatrist 12-14 months later.
METHOD: One hundred and twenty-eight patients referred to our service with a
differential diagnosis of depressive pseudodementia were screened using a
checklist of 44 characteristic features (in the form of questions with 'yes' or
'no' answers) which were claimed in the literature of differentiate between
organic dementia and depressive pseudodementia. This checklist covers the areas
of history, clinical data, insight and performance.
RESULTS: Forty points (questions) out of the 44 in the checklist showed
significant discriminating power to differentiate dementia from depressive
pseudodementia (p < 0.01). A principal component and factor analysis was
performed from which 18 questions were extracted. The shortened questionnaire
was able to classify (43/44 cases) 98% of dementia cases and (60/63) 95% of
depression correctly. A new definition has been introduced for 'pseudodementia'
as a syndrome of reversible subjective or objective cognitive problems caused by
non-organic disorder. Thus depressive pseudodementia may be classified into two
subtypes. Type I is a group of patients who have depressive symptoms with
subject complaint of dysmnesia without measurable intellectual deficits. Type II
is a group of patients who have depressive symptoms and show poor cognitive
performance based on poor concentration not due to organic disorder. Specific symptoms of depression in aged subjects are presented in the paper.
Cognitive dysfunctions in elder depressive patients (so called pseudodementia)
as well as comorbidity of dementia with depression are special diagnostic
problems. Both etiopathogenetic and clinical issues are discussed. Depression and a number of other psychiatric conditions can impair cognition and
give the appearance of neurodegenerative disease. Collectively, this group of
disorders is known as 'pseudodementia' and are important to identify given their
potential reversibility with treatment. Despite considerable interest
historically, the longitudinal outcomes of patients with pseudodementia remain
unclear. We conducted a systematic review of longitudinal studies of
pseudodementia. Bibliographic databases were searched using a wide range of
search terms. Two reviewers independently assessed papers for inclusion, rated
study quality, and extracted data. The search identified 18 studies with
follow-up varying from several weeks to 18 years. Overall, 284 patients were
studied, including 238 patients with depression, 18 with conversion disorder, 14
with psychosis, and 11 with bipolar disorder. Irrespective of diagnosis, 33%
developed irreversible dementia at follow-up, 53% no longer met criteria for
dementia, and 15% were lost to follow-up. Considerable variability was
identified, with younger age at baseline, but not follow-up duration, associated
with better outcomes. ECT and pharmacological interventions were also reported
to be beneficial, though findings were limited by the poor quality of the
studies. Overall, the findings suggest that pseudodementia may confer an
increased risk of irreversible dementia in older patients. The findings also
indicate, however, that a significant proportion improve, while many remain
burdened with their psychiatric condition, independent of organic dementia. The
findings support the clinical value of the construct and the need for its
re-examination in light of developments in neuroimaging, genomics, other
investigative tools, and trial methodology. Dementia has a wide range of reversible causes. Well known among these is
depression, though other psychiatric disorders can also impair cognition and
give the appearance of neurodegenerative disease. This phenomenon has been known
historically as "pseudodementia." Although this topic attracted significant
interest in the 1980s and 1990s, research on the topic has waned. In this paper,
we consider reasons for this decline, including objections to the term itself
and controversy about its distinctness from organic dementia. We discuss
limitations in the arguments put forward and existing research, which,
crucially, does not support inevitable progression. We also discuss other
neglected masquerades, such as of pseudodementia itself
("pseudo-pseudodementia") and depression ("pseudodepression"). Based on this
reappraisal, we argue that these terms, while not replacing modern diagnostic
criteria, remain relevant as they highlight unique groups of patients, potential
misdiagnosis, and important, but neglected, areas of research. |
Should acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) be used when providing supportive care for COVID-19? | Nonsteroidal anti-inflammatory drugs (NSAIDs) have been theorized to cause harm in patients with COVID-19, but clinical data are limited. Given the uncertainty, acetaminophen is the preferred antipyretic agent for most patients rather than NSAIDs. If NSAIDs are needed, the lowest effective dose is recommended. | Given the current SARS-CoV-2 (COVID-19) pandemic, the availability of reliable
information for clinicians and patients is paramount. There have been a number
of reports stating that non-steroidal anti-inflammatory drugs (NSAIDs) and
corticosteroids may exacerbate symptoms in COVID-19 patients. Therefore, this
review aimed to collate information available in published articles to identify
any evidence behind these claims with the aim of advising clinicians on how best
to treat patients. This review found no published evidence for or against the
use of NSAIDs in COVID-19 patients. Meanwhile, there appeared to be some
evidence that corticosteroids may be beneficial if utilised in the early acute
phase of infection, however, conflicting evidence from the World Health
Organisation surrounding corticosteroid use in certain viral infections means
this evidence is not conclusive. Given the current availability of literature,
caution should be exercised until further evidence emerges surrounding the use
of NSAIDs and corticosteroids in COVID-19 patients. Concern about the appropriate role of nonsteroidal anti-inflammatory drugs
(NSAIDs) in COVID-19 speculate that NSAIDs, in particular ibuprofen, may
upregulate the entry point for the virus, the angiotensin-converting enzyme
(ACE) 2 receptors and increase susceptibility to the virus or worsen symptoms in
existing disease. Adverse outcomes with COVID-19 have been linked to cytokine
storm but the most effective way to address exaggerated inflammatory response is
complex and unclear. The Expert Working Group on the Commission of Human
Medicines in the UK and other organizations have stated that there is
insufficient evidence to establish a link between ibuprofen and susceptibility
to or exacerbation of COVID-19. NSAID use must also be categorized by whether
the drugs are relatively low-dose over-the-counter oral products taken
occasionally versus higher-dose or parenteral NSAIDs. Even if evidence emerged
arguing for or against NSAIDs in this setting, it is unclear if this evidence
would apply to all NSAIDs at all doses in all dosing regimens. Paracetamol
(acetaminophen) has been proposed as an alternative to NSAIDs but there are
issues with liver toxicity at high doses. There are clearly COVID-19 cases where
NSAIDs should not be used, but there is no strong evidence that NSAIDs must be
avoided in all patients with COVID-19; clinicians must weigh these choices on an
individual basis. BACKGROUND: Since there is still no definitive conclusion regarding which
non-steroidal anti-inflammatory drugs (NSAIDs) are most effective and safe in
viral respiratory infections, we decided to evaluate the efficacy and safety of
various NSAIDs in viral respiratory infections so that we can reach a conclusion
on which NSAID is best choice for coronavirus disease 2019 (COVID-19).
METHODS: A search was performed in Medline (via PubMed), Embase and CENTRAL
databases until 23 March 2020. Clinical trials on application of NSAIDs in viral
respiratory infections were included.
RESULTS: Six clinical trials were included. No clinical trial has been performed
on COVID-19, Severe Acute Respiratory Syndrome and Middle East Respiratory
Syndrome infections. Studies show that ibuprofen and naproxen not only have
positive effects in controlling cold symptoms, but also do not cause serious
side effects in rhinovirus infections. In addition, it was found that
clarithromycin, naproxen and oseltamivir combination leads to decrease in
mortality rate and duration of hospitalisation in patients with pneumonia caused
by influenza.
CONCLUSION: Although based on existing evidence, NSAIDs have been effective in
treating respiratory infections caused by influenza and rhinovirus, since there
is no clinical trial on COVID-19 and case-reports and clinical experiences are
indicative of elongation of treatment duration and exacerbation of the clinical
course of patients with COVID-19, it is recommended to use substitutes such as
acetaminophen for controlling fever and inflammation and be cautious about using
NSAIDs in management of COVID-19 patients until there are enough evidence.
Naproxen may be a good choice for future clinical trials. AIMS: In light of the recent safety concerns relating to NSAID use in COVID-19,
we sought to evaluate cardiovascular and respiratory complications in patients
taking NSAIDs during acute lower respiratory tract infections.
METHODS: We carried out a systematic review of randomised controlled trials and
observational studies. Studies of adult patients with short-term NSAID use
during acute lower respiratory tract infections, including bacterial and viral
infections, were included. Primary outcome was all-cause mortality. Secondary
outcomes were cardiovascular, renal and respiratory complications.
RESULTS: In total, eight studies including two randomised controlled trials,
three retrospective and three prospective observational studies enrolling 44 140
patients were included. Five of the studies were in patients with pneumonia, two
in patients with influenza, and one in a patient with acute bronchitis.
Meta-analysis was not possible due to significant heterogeneity. There was a
trend towards a reduction in mortality and an increase in pleuro-pulmonary
complications. However, all studies exhibited high risks of bias, primarily due
to lack of adjustment for confounding variables. Cardiovascular outcomes were
not reported by any of the included studies.
CONCLUSION: In this systematic review of NSAID use during acute lower
respiratory tract infections in adults, we found that the existing evidence for
mortality, pleuro-pulmonary complications and rates of mechanical ventilation or
organ failure is of extremely poor quality, very low certainty and should be
interpreted with caution. Mechanistic and clinical studies addressing the
captioned subject are urgently needed, especially in relation to COVID-19. The pathogenesis of Coronavirus disease 2019 is still obscure and the need for
exploration of possible mechanisms to suggest drugs based on knowledge should
never be delayed. In this manuscript, we present a novel theory to explain the
pathogenesis of COVID-19; lymphocyte distraction theory upon which the author
has used, in a preprinted protocol, non-steroidal anti-inflammatory drugs
(NSAIDs); diclofenac potassium, ibuprofen and ketoprofen, successfully to treat
COVID-19 patients. Furthermore, we agree with a recommendation that
glucocorticoids should not be used routinely for COVID-19 patients and suggested
to be beneficial only for patients with late acute respiratory distress
syndrome. A clinical proof of ibuprofen safety in COVID-19 has been published by
other researchers and we suggest that early administration of NSAIDs, including
ibuprofen, in COVID-19 is not only safe but it might also prevent COVID-19
complications and this manuscript explains some of the suggested associated
protective mechanisms. Despite our growing knowledge about the COVID pandemic, not much concern has
been focused upon the effective pain management in pediatric patients suffering
from this SARS CoV2 virus. Symptoms with pain like myalgia (10%-40%), sore
throat (5%-30%), headache (14%-40%) and abdominal pain (10%) are common in
children suffering from COVID. (3-5) We conducted a systematic review regarding
analgesia for COVID positive pediatric patients. Cochrane, PubMed, and Google
scholar databases were searched for relevant literature. Owing to the novel
status of COVID-19 with limited literature, we included randomized controlled
trials (RCTs), observational studies, case series and case reports in the
descending order of consideration. Articles in languages other than English,
abstract only articles and non-scientific commentaries were excluded. The
Primary outcome was evaluation of pain related symptoms and best strategies for
their management. Our review revealed that a multidisciplinary approach starting
from non-pharmacological techniques like drinking plenty of water, removing
triggers like inadequate sleep, specific foods and psychotherapy including
distraction, comfort and cognitive behavioural strategies should be used.
Pharmacological approaches like acetaminophen, NSAIDS, spasmolytics etc. can be
used if non-pharmacological therapy is inadequate. As per the current strength
of evidence, acetaminophen and ibuprofen can be safely administered for pain
management in children with COVID-19. Undertreated pain is a significant
contributor to increased morbidity and poor prognosis. Integration of evidence
based non-pharmacotherapies in the multidisciplinary pain management will
contribute towards improved functioning, early recovery and better quality care
for pediatric patients suffering from COVID. Collaborators: Baillie JK, Semple MG, Openshaw PJ, Carson G, Alex B, Bach B,
Barclay WS, Bogaert D, Chand M, Cooke GS, da Silva Filipe A, de Silva T,
Docherty AB, Dunning J, Fletcher T, Green CA, Harrison EM, Hiscox JA, Ho AY,
Horby PW, Ijaz S, Khoo S, Klenerman P, Law A, Lim WS, Mentzer AJ, Merson L,
Meynert AM, Moore SC, Noursadeghi M, Palmarini M, Paxton WA, Pollakis G, Price
N, Rambaut A, Robertson DL, Russell CD, Sancho-Shimizu V, Scott JT, Sigfrid L,
Solomon T, Sriskandan S, Stuart D, Summers C, Tedder RS, Thompson AAR, Thomson
EC, Thwaites RS, Turtle LC, Zambon M, Donohue C, Griffiths F, Hardwick H, Lyons
R, Oosthuyzen W, Drake TM, Fairfield CJ, Knight SR, Mclean KA, Murphy D, Norman
L, Pius R, Shaw CA, Connor M, Dalton J, Gamble C, Girvan M, Halpin S, Harrison
J, Jackson C, Marsh L, Roberts S, Saviciute E, Clohisey S, Hendry R, Law A,
Leeming G, Scott-Brown J, Wham M, Greenhalf W, McDonald S, Shaw V, Keating S,
Ahmed KA, Armstrong JA, Ashworth M, Asiimwe IG, Bakshi S, Barlow SL, Booth L,
Bren B, Bullock K, Carlucci N, Cass E, Catterall BW, Clark JJ, Clarke EA,
Cole S, Cooper L, Cox H, Davis C, Dincarslan O, Doce Carracedo A, Dunn C, Dyer
P, Elliott A, Evans A, Finch L, Fisher LW, Flaherty L, Foster T, Garcia-Dorival
I, Greenhalf W, Gunning P, Hartley C, Holmes A, Jensen RL, Jones CB, Jones TR,
Khandaker S, King K, Kiy RT, Koukorava C, Lake A, Lant S, Latawiec D,
Lavelle-Langham L, Lefteri D, Lett L, Livoti LA, Mancini M, Massey H, Maziere N,
McDonald S, McEvoy L, McLauchlan J, Metelmann S, Miah NS, Middleton J, Mitchell
J, Moore SC, Murphy EG, Penrice-Randal R, Pilgrim J, Prince T, Reynolds W,
Ridley PM, Sales D, Shaw VE, Shears RK, Small B, Subramaniam KS, Szemiel A,
Taggart A, Tanianis-Hughes J, Thomas J, Trochu E, van Tonder L, Wilcock E, Zhang
JE, MacLean A, McCafferty S, Morrice K, Murphy L, Wrobel N, Adeniji K, Agranoff
D, Agwuh K, Ail D, Aldera EL, Alegria A, Angus B, Ashish A, Atkinson D, Bari S,
Barlow G, Barnass S, Barrett N, Bassford C, Basude S, Baxter D, Beadsworth M,
Bernatoniene J, Berridge J, Best N, Bothma P, Brittain-Long R, Bulteel N, Burden
T, Burtenshaw A, Caruth V, Chadwick D, Chadwick D, Chambler D, Chee N, Child J,
Chukkambotla S, Clark T, Collini P, Cosgrove C, Cupitt J, Cutino-Moguel MT, Dark
P, Dawson C, Dervisevic S, Donnison P, Douthwaite S, DuRand I, Dushianthan A,
Dyer T, Evans C, Eziefula C, Fegan C, Finn A, Fullerton D, Garg S, Garg S, Garg
A, Gkrania-Klotsas E, Godden J, Goldsmith A, Graham C, Hardy E, Hartshorn S,
Harvey D, Havalda P, Hawcutt DB, Hobrok M, Hodgson L, Hormis A, Jacobs M, Jain
S, Jennings P, Kaliappan A, Kasipandian V, Kegg S, Kelsey M, Kendall J, Kerrison
C, Kerslake I, Koch O, Koduri G, Koshy G, Laha S, Laird S, Larkin S, Leiner T,
Lillie P, Limb J, Linnett V, Little J, Lyttle M, MacMahon M, MacNaughton E,
Mankregod R, Masson H, Matovu E, McCullough K, McEwen R, Meda M, Mills G, Minton
J, Mirfenderesky M, Mohandas K, Mok Q, Moon J, Moore E, Morgan P, Morris C,
Mortimore K, Moses S, Mpenge M, Mulla R, Murphy M, Nagarajan T, Nagel M, Nelson
M, O'Shea MK, Ostermann M, Otahal I, Pais M, Panchatsharam S, Papakonstantinou
D, Papineni P, Paraiso H, Patel B, Pattison N, Pepperell J, Peters M, Phull M,
Pintus S, Post F, Price D, Prout R, Rae N, Reschreiter H, Reynolds T, Richardson
N, Roberts M, Roberts D, Rose A, Rousseau G, Ryan B, Saluja T, Sarah S, Shah A,
Shankar-Hari M, Shanmuga P, Sharma A, Shawcross A, Singh Pooni J, Sizer J, Smith
R, Snelson C, Spittle N, Staines N, Stambach T, Stewart R, Subudhi P, Szakmany
T, Tatham K, Thomas J, Thompson C, Thompson R, Tridente A, Tupper-Carey D,
Twagira M, Ustianowski A, Vallotton N, Vincent-Smith L, Visuvanathan S,
Vuylsteke A, Waddy S, Wake R, Walden A, Welters I, Whitehouse T, Whittaker P,
Whittington A, Wijesinghe M, Williams M, Wilson L, Winchester S, Wiselka M,
Wolverson A, Wooton DG, Workman A, Yates B, Young P. |
Is there a way to distinguish COVID-19 clinically from other respiratory illnesses, particularly influenza? | No, the clinical features of COVID-19 overlap substantially with influenza and other respiratory viral illnesses. There is no way to distinguish among them without testing. | Coronavirus disease 2019 (COVID-19) is currently causing a pandemic and will
likely persist in endemic form in the foreseeable future. Physicians need to
correctly approach this new disease, often representing a challenge in terms of
differential diagnosis. Although COVID-19 lacks specific signs and symptoms, we
believe internists should develop specific skills to recognize the disease,
learning its 'semeiotic'. In this review article, we summarize the key clinical
features that may guide in differentiating a COVID-19 case, requiring specific
testing, from upper respiratory and/or influenza-like illnesses of other
aetiology. We consider two different clinical settings, where availability of
the different diagnostic strategies differs widely: outpatient and inpatient.
Our reasoning highlights how challenging a balanced approach to a patient with
fever and flu-like symptoms can be. At present, clinical workup of COVID-19
remains a hard task to accomplish. However, knowledge of the natural history of
the disease may aid the internist in putting common and unspecific symptoms into
the correct clinical context. OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged
as a global pandemic in early 2020 with rapidly evolving approaches to
diagnosing the clinical illness called coronavirus disease (COVID-19). The
primary objective of this scoping review is to synthesize current research of
the diagnostic accuracy of history, physical examination, routine laboratory
tests, real-time reverse transcription-polymerase chain reaction (rRT-PCR),
immunology tests, and computed tomography (CT) for the emergency department (ED)
diagnosis of COVID-19. Secondary objectives included a synopsis of diagnostic
biases likely with current COVID-19 research as well as corresponding
implications of false-negative and false-positive results for clinicians and
investigators.
METHODS: A Preferred Reporting Items for Systematic Reviews and
Meta-Analyses-Scoping Review (PRISMA-ScR)-adherent synthesis of COVID-19
diagnostic accuracy through May 5, 2020, was conducted. The search strategy was
designed by a medical librarian and included studies indexed by PubMed and
Embase since January 2020.
RESULTS: A total of 1,907 citations were screened for relevance. Patients
without COVID-19 are rarely reported, so specificity and likelihood ratios were
generally unavailable. Fever is the most common finding, while hyposmia and
hypogeusia appear useful to rule in COVID-19. Cough is not consistently present.
Lymphopenia is the mostly commonly reported laboratory abnormality and occurs in
over 50% of COVID-19 patients. rRT-PCR is currently considered the COVID-19
criterion standard for most diagnostic studies, but a single test sensitivity
ranges from 60% to 78%. Multiple reasons for false-negatives rRT-PCR exist,
including sample site tested and disease stage during which sample was obtained.
CT may increase COVID-19 sensitivity in conjunction with rRT-PCR, but guidelines
for imaging patients most likely to benefit are emerging. IgM and IgG serology
levels are undetectable in the first week of COVID-19, but sensitivity (range =
82% to 100%) and specificity (range = 87% to 100%) are promising. Whether
detectable COVID-19 antibodies correspond to immunity remains uswered.
Current studies do not adhere to accepted diagnostic accuracy reporting
standards and likely report significantly biased results if the same tests were
to be applied to general ED populations with suspected COVID-19.
CONCLUSIONS: With the exception of fever and disorders of smell/taste, history
and physical examination findings are unhelpful to distinguish COVID-19 from
other infectious conditions that mimic SARS-CoV-2 like influenza. Routine
laboratory tests are also nondiagnostic, although lymphopenia is a common
finding and other abnormalities may predict severe disease. Although rRT-PCR is
the current criterion standard, more inclusive consensus-based criteria will
likely emerge because of the high false-negative rate of PCR tests. The role of
serology and CT in ED assessments remains undefined. As coronavirus disease 2019 (COVID-19) crashed into the influenza season,
clinical characteristics of both infectious diseases were compared to make a
difference. We reported 211 COVID-19 patients and 115 influenza patients as two
separate cohorts at different locations. Demographic data, medical history,
laboratory findings, and radiological characters were summarized and compared
between two cohorts, as well as between patients at the intensive care unit
(ICU) andnon-ICU within the COVID-19 cohort. For all 326 patients, the median
age was 57.0 (interquartile range: 45.0-69.0) and 48.2% was male, while 43.9%
had comorbidities that included hypertension, diabetes, bronchitis, and heart
diseases. Patients had cough (75.5%), fever (69.3%), expectoration (41.1%),
dyspnea (19.3%), chest pain (18.7%), and fatigue (16.0%), etc. Both viral
infections caused substantial blood abnormality, whereas the COVID-19 cohort
showed a lower frequency of leukocytosis, neutrophilia, or lymphocytopenia, but
a higher chance of creatine kinase elevation. A total of 7.7% of all patients
possessed no abnormal sign in chest computed tomography (CT) scans. For both
infections, pulmonary lesions in radiological findings did not show any
difference in their location or distribution. Nevertheless, compared to the
influenza cohort, the COVID-19 cohort presented more diversity in CT features,
where certain specific CT patterns showed significantly more frequency,
including consolidation, crazy paving pattern, rounded opacities, air
bronchogram, tree-in-bud sign, interlobular septal thickening, and bronchiolar
wall thickening. Differentiable clinical manifestations and CT patterns may help
diagnose COVID-19 from influenza and gain a better understanding of both
contagious respiratory illnesses. COVID-19 is a pandemic viral disease with catastrophic global impact. This
disease is more contagious than influenza such that cluster outbreaks occur
frequently. If patients with symptoms quickly underwent testing and contact
tracing, these outbreaks could be contained. Unfortunately, COVID-19 patients
have symptoms similar to other common illnesses. Here, we hypothesize the order
of symptom occurrence could help patients and medical professionals more quickly
distinguish COVID-19 from other respiratory diseases, yet such essential
information is largely unavailable. To this end, we apply a Markov Process to a
graded partially ordered set based on clinical observations of COVID-19 cases to
ascertain the most likely order of discernible symptoms (i.e., fever, cough,
nausea/vomiting, and diarrhea) in COVID-19 patients. We then compared the
progression of these symptoms in COVID-19 to other respiratory diseases, such as
influenza, SARS, and MERS, to observe if the diseases present differently. Our
model predicts that influenza initiates with cough, whereas COVID-19 like other
coronavirus-related diseases initiates with fever. However, COVID-19 differs
from SARS and MERS in the order of gastrointestinal symptoms. Our results
support the notion that fever should be used to screen for entry into facilities
as regions begin to reopen after the outbreak of Spring 2020. Additionally, our
findings suggest that good clinical practice should involve recording the order
of symptom occurrence in COVID-19 and other diseases. If such a systemic
clinical practice had been standard since ancient diseases, perhaps the
transition from local outbreak to pandemic could have been avoided. Coronavirus disease 2019 (COVID-19) has spread in more than 100 countries and
regions around the world, raising grave global concerns. COVID-19 has a similar
pattern of infection, clinical symptoms, and chest imaging findings to influenza
pneumonia. In this retrospective study, we analysed clinical and chest CT data
of 24 patients with COVID-19 and 79 patients with influenza pneumonia.
Univariate analysis demonstrated that the temperature, systolic pressure, cough
and sputum production could distinguish COVID-19 from influenza pneumonia. The
diagnostic sensitivity and specificity for the clinical features are 0.783 and
0.747, and the AUC value is 0.819. Univariate analysis demonstrates that nine CT
features, central-peripheral distribution, superior-inferior distribution,
anterior-posterior distribution, patches of GGO, GGO nodule, vascular
enlargement in GGO, air bronchogram, bronchiectasis within focus, interlobular
septal thickening, could distinguish COVID-19 from influenza pneumonia. The
diagnostic sensitivity and specificity for the CT features are 0.750 and 0.962,
and the AUC value is 0.927. Finally, a multivariate logistic regression model
combined the variables from the clinical variables and CT features models was
made. The combined model contained six features: systolic blood pressure, sputum
production, vascular enlargement in the GGO, GGO nodule, central-peripheral
distribution and bronchiectasis within focus. The diagnostic sensitivity and
specificity for the combined features are 0.87 and 0.96, and the AUC value is
0.961. In conclusion, some CT features or clinical variables can differentiate
COVID-19 from influenza pneumonia. Moreover, CT features combined with clinical
variables had higher diagnostic performance. We conducted a retrospective chart review examining the demographics, clinical
history, physical findings, and comorbidities of patients with influenza and
patients with coronavirus disease 2019 (COVID-19). Older patients, male
patients, patients reporting fever, and patients with higher body mass indexes
(BMIs) were more likely to have COVID-19 than influenza. |
What is the incubation period for COVID-19? | For COVID-19, the mean incubation period was 6.0 days globally but near 7.0 days in the mainland of China, which will help identify the time of infection and make disease control decisions. The Delta VOC yielded a significantly shorter incubation period (4.0 vs. 6.0 days), higher viral load (20.6 vs. 34.0, cycle threshold of the ORF1a/b gene), and a longer duration of viral shedding in pharyngeal swab samples (14.0 vs. 8.0 days) compared with the wild-type strain. | A novel coronavirus disease, designated as COVID-19, has become a pandemic
worldwide. This study aims to estimate the incubation period and serial interval
of COVID-19. We collected contact tracing data in a municipality in Hubei
province during a full outbreak period. The date of infection and
infector-infectee pairs were inferred from the history of travel in Wuhan or
exposed to confirmed cases. The incubation periods and serial intervals were
estimated using parametric accelerated failure time models, accounting for
interval censoring of the exposures. Our estimated median incubation period of
COVID-19 is 5.4 days (bootstrapped 95% confidence interval (CI) 4.8-6.0), and
the 2.5th and 97.5th percentiles are 1 and 15 days, respectively; while the
estimated serial interval of COVID-19 falls within the range of -4 to 13 days
with 95% confidence and has a median of 4.6 days (95% CI 3.7-5.5). Ninety-five
per cent of symptomatic cases showed symptoms by 13.7 days (95% CI 12.5-14.9).
The incubation periods and serial intervals were not significantly different
between male and female, and among age groups. Our results suggest a
considerable proportion of secondary transmission occurred prior to symptom
onset. And the current practice of 14-day quarantine period in many regions is
reasonable. OBJECTIVE: The aim of this study was to explore any age-related change in the
incubation period of COVID-19, specifically any difference between older (aged
≥65 years) and younger adults.
METHODS: Based on online data released officially by 21 Chinese cities from
January 22 to February 15, 2020, the incubation period of COVID-19 patients who
had travelled to Hubei was studied according to age. Previous studies were
reviewed and compared.
RESULTS: The study recruited 136 COVID-19 patients who had travelled to Hubei
during January 5-31, 2020, stayed for 1-2 days, and returned with symptom onset
during January 10-February 6, 2020. The median age was 50.5 years (range 1-86
years), and 22 patients (16.2%) were aged ≥65 years. The age-stratified
incubation period was U-shaped with higher values at extremes of age. The median
COVID-19 incubation period was 8.3 (90% confidence interval [CI], 7.4-9.2) days
for all patients, 7.6 (90% CI, 6.7-8.6) days for younger adults, and 11.2 (90%
CI, 9.0-13.5) days for older adults. The 5th/25th/75th/90th percentiles were
2.3/5.3/11.3/14.2 days for all, 2.0/5.0/10.5/13.2 days for younger adults, and
3.1/7.8/14.4/17.0 days for older adults. There were 11 published studies on
COVID-19 incubation periods up to March 30, 2020, reporting means of
1.8-7.2 days, and medians of 4-7.5 days, but there was no specific study on the
effect of age on incubation period. One study showed that severe COVID-19 cases,
which included more elderly patients, had longer incubation periods.
CONCLUSION: Based on 136 patients with a travel history to Hubei, the epicenter
of COVID-19, the COVID-19 incubation period was found to be longer in older
adults. This finding has important implications for diagnosis, prevention, and
control of COVID-19. OBJECTIVES: The aim of this study was to conduct a rapid systematic review and
meta-analysis of estimates of the incubation period of COVID-19.
DESIGN: Rapid systematic review and meta-analysis of observational research.
SETTING: International studies on incubation period of COVID-19.
PARTICIPANTS: Searches were carried out in PubMed, Google Scholar, Embase,
Cochrane Library as well as the preprint servers MedRxiv and BioRxiv. Studies
were selected for meta-analysis if they reported either the parameters and CIs
of the distributions fit to the data, or sufficient information to facilitate
calculation of those values. After initial eligibility screening, 24 studies
were selected for initial review, nine of these were shortlisted for
meta-analysis. Final estimates are from meta-analysis of eight studies.
PRIMARY OUTCOME MEASURES: Parameters of a lognormal distribution of incubation
periods.
RESULTS: The incubation period distribution may be modelled with a lognormal
distribution with pooled mu and sigma parameters (95% CIs) of 1.63 (95% CI 1.51
to 1.75) and 0.50 (95% CI 0.46 to 0.55), respectively. The corresponding mean
(95% CIs) was 5.8 (95% CI 5.0 to 6.7) days. It should be noted that uncertainty
increases towards the tail of the distribution: the pooled parameter estimates
(95% CIs) resulted in a median incubation period of 5.1 (95% CI 4.5 to 5.8)
days, whereas the 95th percentile was 11.7 (95% CI 9.7 to 14.2) days.
CONCLUSIONS: The choice of which parameter values are adopted will depend on how
the information is used, the associated risks and the perceived consequences of
decisions to be taken. These recommendations will need to be revisited once
further relevant information becomes available. Accordingly, we present an R
Shiny app that facilitates updating these estimates as new data become
available. BACKGROUND: Factors associated with the incubation period of COVID-19 are not
fully known. The aim of this study was to estimate the incubation period of
COVID-19 using epidemiological contact tracing data, and to explore whether
there were different incubation periods among different age gr1oups.
METHODS: We collected contact tracing data in a municipality in Hubei province
during the full outbreak period of COVID-19. The exposure periods were inferred
from the history of travel in Wuhan and/or history of exposure to confirmed
cases. The incubation periods were estimated using parametric accelerated
failure time models accounting for interval censoring of exposures.
RESULTS: The incubation period of COVID-19 follows a Weibull distribution and
has a median of 5.8 days with a bootstrap 95% CI: 5.4-6.7 days. Of the
symptomatic cases, 95% showed symptoms by 14.3 days (95% CI: 13.0-15.7), and 99%
showed symptoms by 18.7 days (95% CI: 16.7-20.9). The incubation periods were
not found significantly different between male and female. Elderly cases had
significant longer incubation periods than young age cases (HR 1.49 with 95% CI:
1.09-2.05). The median incubation period was estimated at 4.0 days (95% CI:
3.5-4.4) for cases aged under 30, 5.8 days (95% CI: 5.6-6.0) for cases aged
between 30 and 59, and 7.7 days (95% CI: 6.9-8.4) for cases aged greater than or
equal to 60.
CONCLUSION: The current practice of a 14-day quarantine period in many regions
is reasonable for any age. Older people infected with SARS-CoV2 have longer
incubation period than that of younger people. Thus, more attention should be
paid to asymptomatic elderly people who had a history of exposure. We compared clinical symptoms, laboratory findings, radiographic signs and
outcomes of COVID-19 and influenza to identify unique features. Depending on the
heterogeneity test, we used either random or fixed-effect models to analyse the
appropriateness of the pooled results. Overall, 540 articles included in this
study; 75,164 cases of COVID-19 (157 studies), 113,818 influenza type A (251
studies) and 9266 influenza type B patients (47 studies) were included. Runny
nose, dyspnoea, sore throat and rhinorrhoea were less frequent symptoms in
COVID-19 cases (14%, 15%, 11.5% and 9.5%, respectively) in comparison to
influenza type A (70%, 45.5%, 49% and 44.5%, respectively) and type B (74%, 33%,
38% and 49%, respectively). Most of the patients with COVID-19 had abnormal
chest radiology (84%, p < 0.001) in comparison to influenza type A (57%, p <
0.001) and B (33%, p < 0.001). The incubation period in COVID-19 (6.4 days
estimated) was longer than influenza type A (3.4 days). Likewise, the duration
of hospitalization in COVID-19 patients (14 days) was longer than influenza type
A (6.5 days) and influenza type B (6.7 days). Case fatality rate of hospitalized
patients in COVID-19 (6.5%, p < 0.001), influenza type A (6%, p < 0.001) and
influenza type B was 3%(p < 0.001). The results showed that COVID-19 and
influenza had many differences in clinical manifestations and radiographic
findings. Due to the lack of effective medication or vaccine for COVID-19,
timely detection of this viral infection and distinguishing from influenza are
very important. OBJECTIVE: To estimate the incubation period of Vietnamese confirmed COVID-19
cases.
METHODS: Only confirmed COVID-19 cases who are Vietnamese and locally infected
with available data on date of symptom onset and clearly defined window of
possible SARS-CoV-2 exposure were included. We used three parametric forms with
Hamiltonian Monte Carlo method for Bayesian Inference to estimate incubation
period for Vietnamese COVID-19 cases. Leave-one-out Information Criterion was
used to assess the performance of three models.
RESULTS: A total of 19 cases identified from 23 Jan 2020 to 13 April 2020 was
included in our analysis. Average incubation periods estimated using different
distribution model ranged from 6.0 days to 6.4 days with the Weibull
distribution demonstrated the best fit to the data. The estimated mean of
incubation period using Weibull distribution model was 6.4 days (95% credible
interval (CrI): 4.89-8.5), standard deviation (SD) was 3.05 (95%CrI 3.05-5.30),
median was 5.6, ranges from 1.35 to 13.04 days (2.5th to 97.5th percentiles).
Extreme estimation of incubation periods is within 14 days from possible
infection.
CONCLUSION: This analysis provides evidence for an average incubation period for
COVID-19 of approximately 6.4 days. Our findings support existing guidelines for
14 days of quarantine of persons potentially exposed to SARS-CoV-2. Although for
extreme cases, the quarantine period should be extended up to three weeks. AIM: This study aims to conduct a review of the existing literature about
incubation period for COVID-19, which can provide insights to the transmission
dynamics of the disease.
METHODS: A systematic review followed by meta-analysis was performed for the
studies providing estimates for the incubation period of COVID-19. The
heterogeneity and bias in the included studies were tested by various
statistical measures, including I2 statistic, Cochran's Q test, Begg's test and
Egger's test.
RESULTS: Fifteen studies with 16 estimates of the incubation period were
selected after implementing the inclusion and exclusion criteria. The pooled
estimate of the incubation period is 5.74 (5.18, 6.30) from the random effects
model. The heterogeneity in the selected studies was found to be 95.2% from the
I2 statistic. There is no potential bias in the included studies for
meta-analysis.
CONCLUSION: This review provides sufficient evidence for the incubation period
of COVID-19 through various studies, which can be helpful in planning preventive
and control measures for the disease. The pooled estimate from the meta-analysis
is a valid and reliable estimate of the incubation period for COVID-19. BACKGROUND: Understanding the epidemiological parameters that determine the
transmission dynamics of COVID-19 is essential for public health intervention.
Globally, a number of studies were conducted to estimate the average serial
interval and incubation period of COVID-19. Combining findings of existing
studies that estimate the average serial interval and incubation period of
COVID-19 significantly improves the quality of evidence. Hence, this study aimed
to determine the overall average serial interval and incubation period of
COVID-19.
METHODS: We followed the PRISMA checklist to present this study. A comprehensive
search strategy was carried out from international electronic databases (Google
Scholar, PubMed, Science Direct, Web of Science, CINAHL, and Cochrane Library)
by two experienced reviewers (MAA and DBK) authors between the 1st of June and
the 31st of July 2020. All observational studies either reporting the serial
interval or incubation period in persons diagnosed with COVID-19 were included
in this study. Heterogeneity across studies was assessed using the I2 and
Higgins test. The NOS adapted for cross-sectional studies was used to evaluate
the quality of studies. A random effect Meta-analysis was employed to determine
the pooled estimate with 95% (CI). Microsoft Excel was used for data extraction
and R software was used for analysis.
RESULTS: We combined a total of 23 studies to estimate the overall mean serial
interval of COVID-19. The mean serial interval of COVID-19 ranged from 4. 2 to
7.5 days. Our meta-analysis showed that the weighted pooled mean serial interval
of COVID-19 was 5.2 (95%CI: 4.9-5.5) days. Additionally, to pool the mean
incubation period of COVID-19, we included 14 articles. The mean incubation
period of COVID-19 also ranged from 4.8 to 9 days. Accordingly, the weighted
pooled mean incubation period of COVID-19 was 6.5 (95%CI: 5.9-7.1) days.
CONCLUSIONS: This systematic review and meta-analysis showed that the weighted
pooled mean serial interval and incubation period of COVID-19 were 5.2, and
6.5 days, respectively. In this study, the average serial interval of COVID-19
is shorter than the average incubation period, which suggests that substantial
numbers of COVID-19 cases will be attributed to presymptomatic transmission. SARS-CoV-2, a member of the family coronaviridae, has triggered a lethal
pandemic termed coronavirus disease 2019 (COVID-19). Pediatric patients, mainly
from families with a cluster of infection or a history of exposure to epidemic
areas, get infected via direct contacts or air-borne droplets. Children (aged
below 18 years) are susceptible to COVID-19, with an average incubation period
of about 6.5 days. Most cases present asymptomatic or common cold symptoms such
as fever, cough, and myalgia or fatigue, which is milder than adult patients.
Besides, most abnormal laboratory and radiologic findings in children with
COVID-19 are non-specific. Since no specific chemotherapeutic agents have been
approved for children, timely preventive methods could effectively forestall the
transmission of SARS-CoV-2. To date, mostly studied cases have been adults with
COVID-19, whereas data on pediatrics patients remain poorly defined. We herein
conducted a literature review for papers published in PubMed and medRxiv
(preprints) between December 2019 and December 2020 that reported on pediatrics
patients (aged below 18 years) with a confirmed COVID-19 diagnosis. In this
review, we summarized and discussed the pathogenesis, epidemiology, and clinical
management of COVID-19 in pediatrics patients to improve our understanding of
this new disease in children. Author information:
(1)Department of Epidemiology and Biostatistics, Indiana University School of
Public Health-Bloomington, IN, USA. Electronic address: [email protected].
(2)Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka,
Japan.
(3)Department of Epidemiology and Biostatistics, Indiana University School of
Public Health-Bloomington, IN, USA.
(4)Department of Virology II, National Institute of Infectious Diseases, Tokyo,
Japan; Department of Applied Biological Science, Tokyo University of Science,
Noda, Japan.
(5)National Center for Global Health and Medicine, Tokyo, Japan.
(6)Department of Virology II, National Institute of Infectious Diseases, Tokyo,
Japan; Department of Applied Biological Science, Tokyo University of Science,
Noda, Japan; MIRAI, JST, Saitama, Japan; Institute for Frontier Life and Medical
Sciences, Kyoto University, Kyoto, Japan.
(7)International Research Center for Neurointelligence, The University of Tokyo,
Tokyo, Japan.
(8)Graduate School of Medicine, Hokkaido University, Hokkaido, Japan.
(9)Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka,
Japan; MIRAI, JST, Saitama, Japan; Institute for the Advanced Study of Human
Biology (ASHBi), Kyoto University, Kyoto, Japan; NEXT-Ganken Program, Japanese
Foundation for Cancer Research (JFCR), Tokyo, Japan; Science Groove Inc.,
Fukuoka, Japan. Electronic address: [email protected]. The COVID-19 pandemic has been causing serious disasters to mankind. The
incubation period is a key parameter for epidemic control and also an important
basis for epidemic prediction, but its distribution law remains unclear. This
paper analyzed the epidemiological information of 787 confirmed non-Wuhan
resident cases, and systematically studied the characteristics of the incubation
period of COVID-19 based on the interval-censored data estimation method. The
results show that the incubation period of COVID-19 approximately conforms to
the Gamma distribution with a mean value of 7.8 (95%CI:7.4-8.5) days and a
median value of 7.0 (95%CI:6.7-7.3) days. The incubation period was positively
correlated with age and negatively correlated with disease severity. Female
cases presented a slightly higher incubation period than that of males. The
proportion of infected persons who developed symptoms within 14 days was 91.6%.
These results are of great significance to the prevention and control of the
COVID-19 pandemic. BACKGROUND: The aim of our study was to determine through a systematic review
and meta-analysis the incubation period of COVID-19. It was conducted based on
the preferred reporting items for systematic reviews and meta-analyses (PRISMA).
Criteria for eligibility were all published population-based primary literature
in PubMed interface and the Science Direct, dealing with incubation period of
COVID-19, written in English, since December 2019 to December 2020. We estimated
the mean of the incubation period using meta-analysis, taking into account
between-study heterogeneity, and the analysis with moderator variables.
RESULTS: This review included 42 studies done predomitly in China. The mean
and median incubation period were of maximum 8 days and 12 days respectively. In
various parametric models, the 95th percentiles were in the range 10.3-16 days.
The highest 99th percentile would be as long as 20.4 days. Out of the 10
included studies in the meta-analysis, 8 were conducted in China, 1 in
Singapore, and 1 in Argentina. The pooled mean incubation period was 6.2 (95% CI
5.4, 7.0) days. The heterogeneity (I2 77.1%; p < 0.001) was decreased when we
included the study quality and the method of calculation used as moderator
variables (I2 0%). The mean incubation period ranged from 5.2 (95% CI 4.4 to
5.9) to 6.65 days (95% CI 6.0 to 7.2).
CONCLUSIONS: This work provides additional evidence of incubation period for
COVID-19 and showed that it is prudent not to dismiss the possibility of
incubation periods up to 14 days at this stage of the epidemic. ANTECEDENTES Y OBJETIVO: El período de incubación de la COVID-19 ayuda a
determinar la duración óptima del período de cuarentena y a crear modelos
predictivos de curvas de incidencia. Se han reportado resultados variables en
recientes estudios y, por ello, el objetivo de esta revisión sistemática es
proporcionar una estimación más precisa del período de incubación de la
COVID-19.
MÉTODOS: Se realizó una búsqueda bibliográfica en las bases de datos de Pubmed,
Scopus/EMBASE y la Cochrane Library, incluyendo todos los estudios
observacionales y experimentales que reportaban un período de incubación y que
se habían publicado entre el 1 de enero y el 21 de marzo de 2020. Se estimó la
media y el percentil 95 del período de incubación mediante metaanálisis,
teniendo en cuenta la heterogeneidad entre los estudios y el análisis con
variables moderadoras.
RESULTADOS: Se incluyeron siete estudios (n = 792) en el metaanálisis. La
heterogeneidad (I2 83,0%, p < 0,001) disminuyó significativamente cuando se tuvo
en cuenta la calidad del estudio y el modelo estadístico utilizado como
variables moderadoras (I2 15%). El período medio de incubación oscilaba entre
5,6 (IC 95%: 5,2 a 6,0) y 6,7 días (IC 95%: 6,0 a 7,4), según el modelo
estadístico utilizado. El percentil 95 fue de 12,5 días cuando la edad media de
los pacientes era de 60 años, aumentando un día por cada 10 años de edad.
CONCLUSIÓN: Según los datos publicados sobre el período de incubación de la
COVID-19, el tiempo medio entre la exposición y la aparición de los síntomas
clínicos depende del modelo estadístico utilizado y el percentil 95, de la edad
media de los pacientes. Se recomienda registrar el sexo y la edad en la recogida
de los datos para poder analizar los posibles patrones diferenciales. Incubation period is an important parameter to inform quarantine period and to
study transmission dynamics of infectious diseases. We conducted a systematic
review and meta-analysis on published estimates of the incubation period
distribution of coronavirus disease 2019, and showed that the pooled median of
the point estimates of the mean, median and 95th percentile for incubation
period are 6.3 days (range, 1.8-11.9 days), 5.4 days (range, 2.0-17.9 days), and
13.1 days (range, 3.2-17.8 days), respectively. Estimates of the mean and 95th
percentile of the incubation period distribution were considerably shorter
before the epidemic peak in China compared to after the peak, and variation was
also noticed for different choices of methodological approach in estimation. Our
findings implied that corrections may be needed before directly applying
estimates of incubation period into control of or further studies on emerging
infectious diseases. We propose a novel model based on a set of coupled delay differential equations
with fourteen delays in order to accurately estimate the incubation period of
COVID-19, employing publicly available data of confirmed corona cases. In this
goal, we separate the total cases into fourteen groups for the corresponding
fourteen incubation periods. The estimated mean incubation period we obtain is
6.74 days (95% Confidence Interval(CI): 6.35 to 7.13), and the 90th percentile
is 11.64 days (95% CI: 11.22 to 12.17), corresponding to a good agreement with
statistical supported studies. This model provides an almost zero-cost
computational complexity to estimate the incubation period. BACKGROUND: As a highly contagious disease, coronavirus disease 2019 (COVID-19)
is wreaking havoc around the world due to continuous spread among close contacts
mainly via droplets, aerosols, contaminated hands or surfaces. Therefore,
centralized isolation of close contacts and suspected patients is an important
measure to prevent the transmission of COVID-19. At present, the quarantine
duration in most countries is 14 d due to the fact that the incubation period of
severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is usually
identified as 1-14 d with median estimate of 4-7.5 d. Since COVID-19 patients in
the incubation period are also contagious, cases with an incubation period of
more than 14 d need to be evaluated.
CASE SUMMARY: A 70-year-old male patient was admitted to the Department of
Respiratory Medicine of The First Affiliated Hospital of Harbin Medical
University on April 5 due to a cough with sputum and shortness of breath. On
April 10, the patient was transferred to the Fever Clinic for further treatment
due to close contact to one confirmed COVID-19 patient in the same room. During
the period from April 10 to May 6, nucleic acid and antibodies to SARS-CoV-2
were tested 7 and 4 times, respectively, all of which were negative. On May 7,
the patient developed fever with a maximum temperature of 39℃, and his
respiratory difficulties had deteriorated. The results of nucleic acid and
antibody detection of SARS-CoV-2 were positive. On May 8, the nucleic acid and
antibody detection of SARS-CoV-2 by Heilongjiang Provincial Center for Disease
Control were also positive, and the patient was diagnosed with COVID-19 and
reported to the Chinese Center for Disease Control and Prevention.
CONCLUSION: This case highlights the importance of the SARS-CoV-2 incubation
period. Further epidemiological investigations and clinical observations are
urgently needed to identify the optimal incubation period of SARS-CoV-2 and
formulate rational and evidence-based quarantine policies for COVID-19
accordingly. BACKGROUND: Coronavirus disease 2019 (COVID-19) has caused a heavy disease
burden globally. The impact of process and timing of data collection on the
accuracy of estimation of key epidemiological distributions are unclear. Because
infection times are typically unobserved, there are relatively few estimates of
generation time distribution.
METHODS: We developed a statistical framework to jointly estimate generation
time and incubation period from human-to-human transmission pairs, accounting
for sampling biases. We applied the framework on 80 laboratory-confirmed
human-to-human transmission pairs in China. We further inferred the
infectiousness profile, serial interval distribution, proportions of
presymptomatic transmission, and basic reproduction number (R0) for COVID-19.
RESULTS: The estimated mean incubation period was 4.8 days (95% confidence
interval [CI], 4.1-5.6), and mean generation time was 5.7 days (95% CI,
4.8-6.5). The estimated R0 based on the estimated generation time was 2.2 (95%
CI, 1.9-2.4). A simulation study suggested that our approach could provide
unbiased estimates, insensitive to the width of exposure windows.
CONCLUSIONS: Properly accounting for the timing and process of data collection
is critical to have correct estimates of generation time and incubation period.
R0 can be biased when it is derived based on serial interval as the proxy of
generation time. Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome
coronavirus 2, was first reported in December 2019 in Wuhan, Hubei province,
China. It is now known as a pandemic and a global crisis due to rapid
human-to-human transmission with the vast expansion that has affected almost all
countries. The primary source of the disease is still unknown, but it is
possible that the virus was transmitted through bat to an intermediate host and
then to humans. The main and early symptoms of COVID-19 infection are fatigue,
fever, dry cough, myalgia, and dyspnea. The incubation period of the disease is
about 2-14 days, which is one of the important parameters for planning to
prevent disease outbreak. PT-polymerase chain reaction test is used to diagnose
the disease; chest computed tomography scan, chest X-ray, blood tests, and
symptoms are also very helpful in diagnosing the disease. There is a strong
emphasis on controlling infections and hand hygiene to prevent the transmission
of the disease. There is not enough knowledge about this disease yet, and there
are no specific vaccines or medications available to prevent and treat this
disease. The current review study uses articles indexed on databases of Embase,
Elsevier, PubMed, and World Health Organization and Centers for Disease Control
and Prevention, and keywords of coronavirus, COVID-19, acute respiratory
distress syndrome and China. BACKGROUND: The incubation period is a crucial index of epidemiology in
understanding the spread of the emerging Coronavirus disease 2019 (COVID-19). In
this study, we aimed to describe the incubation period of COVID-19 globally and
in the mainland of China.
METHODS: The searched studies were published from December 1, 2019 to May 26,
2021 in CNKI, Wanfang, PubMed, and Embase databases. A random-effect model was
used to pool the mean incubation period. Meta-regression was used to explore the
sources of heterogeneity. Meanwhile, we collected 11 545 patients in the
mainland of China outside Hubei from January 19, 2020 to September 21, 2020. The
incubation period fitted with the Log-normal model by the coarseDataTools
package.
RESULTS: A total of 3235 articles were searched, 53 of which were included in
the meta-analysis. The pooled mean incubation period of COVID-19 was 6.0 days
(95% confidence interval [CI] 5.6-6.5) globally, 6.5 days (95% CI 6.1-6.9) in
the mainland of China, and 4.6 days (95% CI 4.1-5.1) outside the mainland of
China (P = 0.006). The incubation period varied with age (P = 0.005). Meanwhile,
in 11 545 patients, the mean incubation period was 7.1 days (95% CI 7.0-7.2),
which was similar to the finding in our meta-analysis.
CONCLUSIONS: For COVID-19, the mean incubation period was 6.0 days globally but
near 7.0 days in the mainland of China, which will help identify the time of
infection and make disease control decisions. Furthermore, attention should also
be paid to the region- or age-specific incubation period. BACKGROUND: A novel variant of SARS-CoV-2, the Delta variant of concern (VOC,
also known as lineage B.1.617.2), is fast becoming the domit strain globally.
We reported the epidemiological, viral, and clinical characteristics of
hospitalized patients infected with the Delta VOC during the local outbreak in
Guangzhou, China.
METHODS: We extracted the epidemiological and clinical information pertaining to
the 159 cases infected with the Delta VOC across seven transmission generations
between May 21 and June 18, 2021. The whole chain of the Delta VOC transmission
was described. Kinetics of viral load and clinical characteristics were compared
with a cohort of wild-type infection in 2020 admitted to the Guangzhou Eighth
People's Hospital.
FINDINGS: There were four transmission generations within the first ten days.
The Delta VOC yielded a significantly shorter incubation period (4.0 vs. 6.0
days), higher viral load (20.6 vs. 34.0, cycle threshold of the ORF1a/b gene),
and a longer duration of viral shedding in pharyngeal swab samples (14.0 vs. 8.0
days) compared with the wild-type strain. In cases with critical illness, the
proportion of patients over the age of 60 was higher in the Delta VOC group than
in the wild-type strain (100.0% vs. 69.2%, p = 0.03). The Delta VOC had a higher
risk than wild-type infection in deterioration to critical status (hazards ratio
2.98 [95%CI 1.29-6.86]; p = 0.01).
INTERPRETATION: Infection with the Delta VOC is characterized by markedly
increased transmissibility, viral loads and risk of disease progression compared
with the wild-type strain, calling for more intensive prevention and control
measures to contain future outbreaks.
FUNDING: National Grand Program, National Natural Science Foundation of China,
Guangdong Provincial Department of Science and Technology, Guangzhou Laboratory. BACKGROUND: COVID-19 patients with long incubation period were reported in
clinical practice and tracing of close contacts, but their epidemiological or
clinical features remained vague.
METHODS: We analyzed 11,425 COVID-19 cases reported between January-August, 2020
in China. The accelerated failure time model, Logistic and modified Poisson
regression models were used to investigate the determits of prolonged
incubation period, as well as their association with clinical severity and
transmissibility, respectively.
RESULT: Among local cases, 268 (10.2%) had a prolonged incubation period of
> 14 days, which was more frequently seen among elderly patients, those residing
in South China, with disease onset after Level I response measures
administration, or being exposed in public places. Patients with prolonged
incubation period had lower risk of severe illness (ORadjusted = 0.386, 95% CI:
0.203-0.677). A reduced transmissibility was observed for the primary patients
with prolonged incubation period (50.4, 95% CI: 32.3-78.6%) than those with an
incubation period of ≤14 days.
CONCLUSIONS: The study provides evidence supporting a prolonged incubation
period that exceeded 2 weeks in over 10% for COVID-19. Longer monitoring periods
than 14 days for quarantine or persons potentially exposed to SARS-CoV-2 should
be justified in extreme cases, especially for those elderly. |
What is Guillain-Barre syndrome (GBS)? | Guillain-Barré syndrome (GBS) is an acute immune mediated neuropathy, polyradiculoneuritis, characterized by rapid onset of symmetric extremity muscle paralysis, areflexia and albuminocytological dissociation in the cerebrospinal fluid (CSF). Recently, the heterogeneity of GBS has been noticed with definition of several GBS variants. The diagnosis of GBS includes clinical, electrophysiological and laboratory (CSF) criteria. | Guillain-Barré syndrome (GBS) is a complicated degenerative disorder which can
be chronic or acute in nature. Its etiology is unclear although it has been
associated with both cell- and humoral-mediated autoimmune mechanisms.
Pathophysiologic effects of the disease include inflammation, demyelination of
peripheral nerves, loss of granular bodies and degeneration of the basement
membrane of the Schwann cell. This results in ascending paralysis and loss of
cranial nerve function. Manifestations may be acute or chronic, and temporary or
permanent, depending upon the degree of neuronal destruction. Due to the
pervasive nature of GBS, nursing care is a challenge. Assessment of motor,
respiratory and cardiac function is of key importance. Total care of the patient
focuses on risks related to impaired mobility and ineffective airway clearance.
Psychosocial care and patient education are also integral components of care. Acute Guillain-Barre syndrome (GBS) is a demyelinating polyneuropathy which
responds readily to plasma exchange (PEX). According to the North American Acute
GBS PEX study there is a 50% or more reduction in the recovery time if PEX is
initiated early in the course of the disease. Demyelinating antibodies are
usually IgM. IgA antibodies require prolonged PEX. Patients with predomit IgG
antibodies have chronic inflammatory demyelinating polyneuropathy (CIDP), which
requires an even longer course of PEX, over weeks to months or years. We
reviewed records of 73 patients with the initial diagnosis of GBS treated with
PEX. Among these patients, 55 had classic GBS, three had the Miller-Fisher
variant, two had CIDP, and 13 had demyelinating-like polyneuropathies associated
with other conditions including maligcy, vaccine-related myelitis,
steroid-induced myopathy, polymyositis, botulism, gram-negative sepsis,
Sjogren's, and AIDS. Hughes grading system was used. Patients were graded 3 to
5, with grade 3 patients being unable to walk 5 m without support, grade 4
patients being bed or chair bound, and grade 5 patients being ventilator
dependent. Of 60 unassociated (GBS) demyelinating cases receiving a mean of 6.5
PEX procedures, 13 (21%) were intubated early in the treatment, with four (6%)
remaining ventilator dependent post-PEX. Of 51 non-intubated patients, 15 became
ambulatory post-PEX. Patients with the Miller-Fisher variant showed improvement
within 6 hours of PEX initiation. We did not investigate correlation of GBS with
infection; however, we did observe a rise in CMV titer among 15% of the 58
patients with acute GBS. Considering our results we believe that intensive PEX
on a daily basis for a few days is necessary for severely affected individuals.
We advise five to nine procedures at consultation unless early, rapid recovery
occurs. OBJECTIVE: To review about this disorder, with emphasis on the intensive care of
severe Guillain Barr syndrome (GBS).
DEVELOPMENT: GBS is an acute immune mediated inflammatory polyneuropathy that
may lead to quadriparesis, ventilatory failure, and autonomic dysfunction but
also to many general medical problems that have great bearing on outcome.
Therefore severe GBS patients require admission into an intensive care unit
(ICU), where in addition to the disorders mentioned before, other complications
can arise. The neurologist who plans to deal comprehensively with these patients
must be familiar with therapy for infections, nutrition, fluid management, and
selected aspects of pulmonary medicine as well as the indications for and
complications of plasma exchange and gammaglobulin infusion.
CONCLUSIONS: With modern intensive care support, the outcome is excellent (>80%
recovery), although in many cases a persistent residual paresis occurs. Because
GBS is largely self limited, the skill daily cares of these patients in an ICU
contributes as much, or more, to the overall outcome of an individual patient as
do specific immune therapies. Guillain-Barré syndrome (GBS) is clinically defined as an acute peripheral
neuropathy causing limb weakness that progresses over a time period of days or,
at the most, up to 4 weeks. GBS occurs throughout the world with a median annual
incidence of 1.3 cases per population of 100 000, with men being more frequently
affected than women. GBS is considered to be an autoimmune disease triggered by
a preceding bacterial or viral infection. Campylobacter jejuni, cytomegalovirus,
Epstein-Barr virus and Mycoplasma pneumoniae are commonly identified antecedent
pathogens. In the acute motor axonal neuropathy (AMAN) form of GBS, the
infecting organisms probably share homologous epitopes to a component of the
peripheral nerves (molecular mimicry) and, therefore, the immune responses
cross-react with the nerves causing axonal degeneration; the target molecules in
AMAN are likely to be gangliosides GM1, GM1b, GD1a and GalNAc-GD1a expressed on
the motor axolemma. In the acute inflammatory demyelinating polyneuropathy
(AIDP) form, immune system reactions against target epitopes in Schwann cells or
myelin result in demyelination; however, the exact target molecules in the case
of AIDP have not yet been identified. AIDP is by far the most common form of GBS
in Europe and North America, whereas AMAN occurs more frequently in east Asia
(China and Japan). The prognosis of GBS is generally favourable, but it is a
serious disease with a mortality of approximately 10% and approximately 20% of
patients are left with severe disability. Treatment of GBS is subdivided into:
(i) the management of severely paralysed patients with intensive care and
ventilatory support; and (ii) specific immunomodulating treatments that shorten
the progressive course of GBS, presumably by limiting nerve damage. High-dose
intravenous immunoglobulin (IVIg) therapy and plasma exchange aid more rapid
resolution of the disease. The predomit mechanisms by which IVIg therapy
exerts its action appear to be a combined effect of complement inactivation,
neutralisation of idiotypic antibodies, cytokine inhibition and saturation of Fc
receptors on macrophages. Corticosteroids alone do not alter the outcome of GBS. Guillain-Barré syndrome (GBS) is an autoimmune disease that leads to an axonal
demyelination and/or degeneration of peripheral nerves through molecular
mimicry. The usual pattern is an ascending areflexic motor paralysis with a
distinct cerebral-spinal fluid (CSF) showing elevated protein level without
accompanying pleocytosis. Diagnosis is essentially clinical, but the CSF studies
and electrodiagnostic features may help confirming the diagnosis. Prognosis is
usually good, with complete recovery in 80-85% of the cases. However, 10% will
remain with permanent neurological damage and about 5% will die.
Immunomodulation is the goal treatment, but supportive care is of the utmost
importance in the treatment and prevention of complications. The purpose of this
work was to review all GBS diagnosed between 1st January 1997 and 31st December
2001, in patients 18 or older admitted to Hospital Pedro Hispano (Portugal).
During the 5-year study period, 62446 patients were admitted to hospital, of
which 15 with GBS. Thirteen had a good evolution: 10 with total recovery over a
period of a maximum of six months; one remain with serious neurological damage
at 2 years of evolution and the remaining one died with a pure motor form of GBS
(both had a previous gastrointestinal infection). The results of this review are
in accordance with what is described in the literature, regarding incidence,
epidemiological data and clinical behaviour. Guillain-Barré syndrome (GBS) is an acute immune mediated neuropathy,
polyradiculoneuritis, characterized by rapid onset of symmetric extremity muscle
paralysis, areflexia and albuminocytological dissociation in the cerebrospinal
fluid (CSF). Recently, the heterogeneity of GBS has been noticed with definition
of several GBS variants. The axonal GBS associated with anti-GM1 antibodies is
the most important variant with the specific role of Campylobacterjejuni (CJ) in
the induction of the disease. The role of our study was to determine the
frequency of antecedent infection with CJ in the population of our patients with
GBS, the association with anti-GM1 antibodies and the distribution of these
antibodies within clinical forms of the disease. The diagnosis of GBS has been
established in 17 patients according to clinical, electrophysiological and
laboratory (CSF) criteria. The serum antibodies to 63 kDa flagellar protein
isolated from CJ serotype 0:19 were determined by ELISA and Western blot and
serum anti-GM1 antibodies by ELISA. In relation to the disability score two
patients were ambulatory, five were ambulatory with support, seven were
bedridden and two patients needed respirator. Five (29%) patients had pure
motor, while 12 (71%) had sensorimotor GBS. The cranial nerves were involved in
11 (65%) and 9 (53%) patients had autonomic dysfunction. Electromyoneurography
showed primary axonal, predomitly motor neuropathy in 6 (35%) and
demyelinating sensorimotor neuropathy in 11 (65%) patients. The CSF protein
content ranged from 0.47 to 3.88 g/L. The antecedent infection with CJ was shown
by serum antibodies to CJ flagellar protein in 12 (71%) patients. Fifteen (88%)
patients had IgG anti-GM1 antibodies. Twelve (71%) patients had both antibodies.
In relation to the clinical form, anti-CJ antibodies were found in 8 (73%) out
of 11 patients with demyelinating GBS and in 4 (66.6%) out of 6 patients with
axonal GBS. The high titer of anti-GM1 antibodies was found in all patients
(100%) with axonal and in 9 (82%) out of 11 patients with demyelinating GBS. The
association of IgG anti-CJ and IgG anti-GM1 antibodies was found in 4 (66.6%)
out of 6 patients with axonal and in 8 (73%) out of 11 patients with
demyelinating GBS. The main features of our patients with GBS were high
frequency of antecedent infection with CJ, unusually frequent association with
anti-GM1 antibodies, and equally frequent association of anti-CJ and anti-GM1
antibodies in both, axonal and demyelinating GBS. Guillain-Barré syndrome (GBS) is an autoimmune acute peripheral neuropathy.
Frequently a flu-like episode or a gastroenteritis precede GBS, and the
cross-reactivity between microbial and neural antigens partly explains the
pathophysiology of the disease and the possible detection of antiganglioside
antibodies. The weakness reaches its nadir in 2-4 weeks: the patients may be
chair- or bed-bound, may need artificial ventilation and frequently experience
dysautonomic dysfunction; 5-15% of the patients die and more patients are left
with a disabling motor deficit and/or fatigue. Electrophysiology and
cerebrospinal fluid evaluation support the diagnosis. The treatment of GBS is
multidisciplinary, and both plasma exchange and high dose immunoglobulin (IVIg)
are effective in reducing both the severity of the disease and the residual
deficits. Finally, steroids are not effective in GBS. Acute Inflammatory Demyelinating Polyneuropathy--Guillain-Barre syndrome (GBS)
affects spinal roots, peripheral and cranial nerves. Various clinical variants
of GBS have been described. Isolated cranial nerve involvement without prominent
signs of GBS is considered as rare variant of this disease. The aim of the study
was to identify clinical characteristics of various forms of GBS particularly in
rare variants of the disease. 57 patients with GBS were evaluated based on
clinical and electrophysiological data. The following forms of GBS were
revealed: 27 had acute inflammatory demyelinating polyradiculoneuropathy,
9--acute motor axonal neuropathy, 12--acute motor and sensory axonal neuropathy,
5--Fisher syndrome and 3--facial diplegia (rare clinical variant). 50 patients
were graded 3 or more according to Hughes functional grading scale. Seasonal
preponderance was found in spring (March-May) and autumn (September-November).
23 patients received IVIG and 34 were treated by plasma exchange within two
weeks after onset. Follow up study revealed: 46 recovered satisfactory, 8 were
persistently disabled, 3 died during admission to hospital. Guillain-Barre
syndrome showed seasonal distribution and high frequency of axonal forms.
Intravenous immunoglobulin therapy was more effective than plasma exchange. Poor
outcomes were likely due to severe condition (required mechanical ventilation)
and axonal forms. It is crucial to timely identify rare variants of GBS which
recover with appropriate treatment. Guillain-Barré syndrome (GBS) is an autoimmune and post-infectious immune
disease. The syndrome includes several pathological subtypes, the most common of
which is a multifocal demyelinating disorder of the peripheral nerves. In the
present review, the main clinical aspects and the basic features of GBS are
discussed along with approaches to diagnosis and treatment. Furthermore, the
pathophysiology of GBS is reviewed, with an emphasis on the production of
symptoms and the course of the disease. Guillain-Barre syndrome (GBS) is a postinfectious, autoimmune disorder which,
apart from limb weakness, is characterised by cranial nerve involvement.
Bilateral facial nerve palsy is the most common pattern of cranial nerve
involvement in GBS. However, unilateral facial palsy, although uncommon, can be
seen in GBS. We report a rare case of unilateral facial palsy in GBS and
importance of electrophysiological tests including blink study in such cases has
been emphasised. Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy,
which has various clinical presentations and both axonal and demyelinating
forms. The original description of "ascending paralysis" encompasses the most
common varieties: the primary demyelinating form, acute inflammatory
demyelinating polyneuropathy (AIDP), and some of the axonal forms, acute motor
axonal neuropathy (AMAN) and acute motor and sensory axonal neuropathy (AMSAN).
However, there are now well-documented acute "monophasic" polyneuropathies that
have a different clinical phenomenology than that described originally by
Guillain, Barré, and Strohl: Miller Fisher syndrome, pure sensory
neuropathy/neuronopathy, pandysautonomia, and oropharyngeal variant. Here the
authors review both typical GBS (AIDP, AMAN, and AMSAN), and variant syndromes
with a focus on clinical and diagnostic features, pathologic findings,
pathogenesis, and treatment. Guillain-Barré syndrome (GBS) is characterized by rapidly evolving ascending
weakness, mild sensory loss, and hyporeflexia or areflexia. Acute inflammatory
demyelinating polyneuropathy was the first to be recognized over a century ago
and is the most common form of GBS. Axonal motor and sensorimotor variants have
been described in the last three decades and are mediated by molecular mimicry
targeting peripheral nerve motor axons. Other rare phenotypic variants have been
recently described with pure sensory variant, restricted autonomic
manifestations, and the pharyngeal-cervical-brachial pattern. It is important to
recognize GBS and its variants because of the availability of equally effective
therapies in the form of plasmapheresis and intravenous immunoglobulins. Guillain-Barré syndrome (GBS) was first described in 1916 (Guillain G, 1916) and
is approaching its 100th anniversary. Our knowledge of the syndrome has hugely
expanded since that time. Once originally considered to be only demyelinating in
pathology we now recognise both axonal and demyelinating subtypes. Numerous
triggering or antecedent events including infections are recognised and GBS is
considered an immunological response to these. GBS is now considered to be a
clinical syndrome of an acute inflammatory neuropathy encompassing a number of
subtypes with evidence of different immunological mechanisms. Some of these are
clearly understood while others remain to be fully elucidated. Complement fixing
antibodies against peripheral nerve gangliosides alone and in combination are
increasingly recognised as an important mechanism of nerve damage. New
antibodies against other nerve antigens such as neurofascin have been recently
described. Research databases have been set up to look at factors associated
with prognosis and the influence of intravenous immunoglobulin (IvIg)
pharmacokinetics in therapy. Exciting new studies are in progress to examine a
possible role for complement inhibition in the treatment of the syndrome. Guillain-Barré syndrome (GBS) is an autoimmune polyneuropathy which presents
with acute onset and rapid progression of flaccid, hyporeflexi quadriparesis.
Both sensory and autonomic nerve involvement is seen. GBS has various subtypes
that vary in their pathophysiology. The pathogenesis involves an immune response
triggered by a preceding event which may be an infection, immunisation or
surgical procedure. Clinical diagnosis has been largely the primary diagnosing
criterion for GBS along with electrodiagnosis, which has several pitfalls and is
supported by ancillary testing of cerebrospinal fluid (CSF) analysis and Nerve
Conduction Studies. Measurement of anti-ganglioside antibodies is also an
effective tool in its diagnosis. Further understanding of pathophysiology and
better diagnostic methods are required for better management of GBS. Guillain-Barré syndrome (GBS) is an acute self-limited polyneuropathy named
after Guillain, Barré, and Strohl, who first reported it in 1916. GBS was
considered a demyelinating disease until the 1980s, when the acute axonal type
of GBS was first reported. Since then, acute inflammatory demyelinating
polyneuropathy and acute motor axonal neuropathy have been considered the two
main subtypes of GBS. Autoimmunity underlies the pathogenesis of GBS. The
presence of antibodies against various glycolipids in the acute-phase sera from
patients with GBS has frequently been reported since the late 1980s. The
effectiveness of plasmapheresis and intravenous immunoglobulin therapy has been
established since the mid-1980s. However, severe or refractory cases still occur
and further investigation is necessary for the development of novel treatments
that are effective for such cases. Guillain-Barre Syndrome is a well described acute demyelinating
polyradiculoneuropathy with a likely autoimmune basis characterized by
progressive ascending muscle paralysis. Classically, GBS is attributed to
antecedent upper respiratory and gastrointestinal infections. We present the
first case of GBS after Robotically Assisted Laparoscopic Prostatectomy using
the daVinci(®) Surgical System. PURPOSE OF REVIEW: This article reviews the current state of Guillain-Barré
syndrome (GBS), including its clinical presentation, evaluation,
pathophysiology, and treatment.
RECENT FINDINGS: GBS is an acute/subacute-onset polyradiculoneuropathy typically
presenting with sensory symptoms and weakness over several days, often leading
to quadriparesis. Approximately 70% of patients report a recent preceding upper
or lower respiratory tract infection or gastrointestinal illness. Approximately
30% of patients require intubation and ventilation because of respiratory
failure. Nerve conduction studies in the acute inflammatory demyelinating
polyradiculoneuropathy (AIDP) form of GBS typically show evidence for a
multifocal demyelinating process, including conduction block or temporal
dispersion in motor nerves. Sural sparing is a common phenomenon when testing
sensory nerves. CSF analysis commonly shows an elevated protein, but this
elevation may not be present until the third week of the illness. Patients with
AIDP are treated with best medical management and either IV immunoglobulin
(IVIg) or plasma exchange.
SUMMARY: GBS is a common form of acute quadriparesis; a high level of suspicion
is needed for early diagnosis. With appropriate therapy, most patients make a
very good to complete recovery. Guillain-Barre syndrome (GBS) is an autoimmune polyradiculoneuropathy usually
preceded by respiratory tract or gastrointestinal infection. The pathogenesis in
GBS is based on molecular mimicry mechanism. Hansen's disease is common in India
and is the most common infectious cause of neuropathy. We describe a 42-year-old
man who was being treated for borderline tuberculoid leprosy and developed Type
1 lepra reaction followed by GBS and responded to plasmapheresis. Lepra reaction
may lead to exposure of neural antigens, resulting in autoimmune mechanism and
demyelination of peripheral nerves. Guillain-Barre syndrome (GBS) is the leading cause of acute paralysis that can
potentially affect all of the human population. GBS is believed to be an
immune-mediated disease, possibly triggered by a recent infection, and driven by
an immune attack targeting the peripheral nervous system. GBS can be divided
into several subtypes depending on the phenotype, pathophysiology, and
neurophysiological features. Unfortunately, morbidity and mortality rates are
still high despite the current understanding of the pathophysiology and
available treatment options. Additional research is still needed to shed more
light into the pathogenesis for a better understanding and treatment of this
condition. Guillain-Barre syndrome (GBS) is a life-threatening immune-mediated acute
inflammatory polyneuropathy and is associated with various antecedent
infections. Its association with tuberculosis is very uncommon with only a
handful of cases being reported in the literature. It's association with
tuberculous meningitis is even more scarce with only one case reported in
literature till date. We report a 40-year-old lady with GBS associated with
tuberculous meningitis. GBS was confirmed with clinical examination and nerve
conduction studies. Objective Guillain Barre syndrome (GBS) is an autoimmune-mediated, acute,
symmetrical, flaccid paralysis. Guillain Barre syndrome has different
electrophysiological types that carry prognostic significance and tend to differ
between adults and children. This study aims to compare the clinical outcome of
Guillain Barre syndrome in Pakistani children based on their
electrophysiological types to help in understanding and predicting the
prognosis. Study design Observational comparative study Place & duration The
pediatric department, Shifa International Hospital, Islamabad; all patients with
Guillain Barre syndrome seen between 2012 and 2019 Method All children aged one
to 16 years in whom Guillain Barre syndrome was diagnosed based on clinical
history, examination, and electrophysiological findings. Institutional review
board (IRB) approval was taken and data entered on the designed questionnaire.
Chi-square and non-parametric tests were applied for significant association.
Results Twenty-three children were included in the study. Of these, 14 were
males (60.9%) while the mean age was 5.8 (+4.5) years. Acute inflammatory
demyelinating polyneuropathy (AIDP) was found to be the predomit type (9;
39.1%) followed by acute motor and sensory axonal neuropathy (AMSAN) (6;
26.1%), Acute motor axonal neuropathy (AMAN) was diagnosed in four (17.4%)
patients. Six (26.1%) patients needed mechanical ventilation and 10 patients
(43.5%) required intensive care unit (ICU) care. The majority of the patients
(18; 78.3%) received intravenous immunoglobulin (IVIG). Conclusion The study
highlights varied electrophysiological types of GBS in Pakistani children, which
differ in predomice from previous studies. However, various indicators of
poor outcomes that are highlighted in adults, including the older age group,
need for mechanical ventilation, and electrophysiological evidence of axonal
degeneration, were not significant predictors of outcome in children. |
Is lumbar puncture the first test that should be performed on a patient with increased intracranial pressure? | No. A lumbar puncture is contraindicated in any patient with signs of increased intracranial pressure because it may precipitate cerebral herniation and death. For this reason, a computed tomography (CT) or magnetic resonance imaging (MRI) scan is done first. When the findings of the scan are normal, a lumbar puncture can be performed, if needed. | CSF evaluation is the single most important aspect of the laboratory diagnosis
of meningitis. Analysis of the CSF abnormalities produced by bacterial,
mycobacterial, and fungal infections may greatly facilitate diagnosis and direct
initial therapy. Basic studies of CSF that should be performed in all patients
with meningitis include measurement of pressure, cell count and white cell
differential; determination of glucose and protein levels; Gram's stain; and
culture. In bacterial meningitis, Limulus lysate assay and tests to identify
bacterial antigens may allow rapid diagnosis. Where there is strong suspicion of
tuberculous or fungal meningitis, CSF should also be submitted for acid-fast
stain, India ink preparation, and cryptococcal antigen; unless contraindicated
by increased intracranial pressure, large volumes (up to 40-50 mL) should be
obtained for culture. If a history of residence in the Southwest is elicited,
complement-fixing antibodies to Coccidioides immitis should also be ordered.
Newer tests based on immunologic methods or gene amplification techniques hold
great promise for diagnosis of infections caused by organisms that are difficult
to culture or present in small numbers. Despite the great value of lumbar
puncture in the diagnosis of meningitis, injudicious use of the procedure may
result in death from brain herniation. Lumbar puncture should be avoided if
focal neurologic findings suggest concomitant mass lesion, as in brain abscess,
and lumbar puncture should be approached with great caution if meningitis is
accompanied by evidence of significant intracranial hypertension. Institution of
antibiotic therapy for suspected meningitis should not be delayed while
neuroradiologic studies are obtained to exclude abscess or while measures are
instituted to reduce intracranial pressure. Examination of cerebrospinal fluid remains a mainstay of the diagnosis of many
acute central nervous system illnesses, including meningitis, encephalitis, and
polyneuropathies such as Guillain-Barré syndrome. Although generally considered
innocuous, there may be considerable danger when lumbar puncture is performed in
the presence of increased intracranial pressure, especially when a mass lesion
is present. We review the literature surrounding the danger of lumbar puncture
when intracranial pressure is increased and discuss our approach to the problem
in lieu of the advent of computerized tomographic scanning. Death following lumbar puncture (LP) is feared by physicians. Many opinions are
found in literature on the question whether computed cranial tomography (CT)
should be performed before LP, to prevent herniation. These opinions are mainly
based on retrospective studies and pathophysiological reasoning. In this review
the difficulties in the decision whether we should perform CT before LP are
discussed. It is explained that the concept of "raised intracranial pressure" is
confusing, and that the less ambiguous terms "brain shift" and "raised CSF
pressure" should be used instead. Brain shift is a contraindication to LP,
whether CSF pressure is raised or not, and whether papilloedema is present or
not. Subsequently, recommendations are offered for indications to perform CT
before LP, grouped according to the safety and clinical utility of LP. Serious complications (catastrophes) resulting from diverse neurological
diagnostic procedures can be caused by erroneous indication and omission, as
well as by delay and erroneous execution or interpretation. Headache, caused by
cerebrospinal fluid (CSF) hypotension, is a frequent complication of lumbar
puncture; hematic patch is a therapeutic option for severe cases. The most
serious complication is cerebral herniation and, for its prevention, computed
tomography (CT) or cerebral magnetic resoce imaging (MRI) must always be
performed before lumbar puncture: a lesion with evident mass effect is a
contraindication. Some cases of minor subarachnoid hemorrhages can produce
sentinel headache: when the findings of CT scans are normal, lumbar puncture
must be performed for diagnosis and prevention of a catastrophic recurrence.
Edrophonium testing can be complicated with bradycardia and/or asystole. The
lack of indication of this procedure is a cause of under-diagnosis of myasthenia
gravis, especially in older people. Electromyography produces few complications
(rare cases of paraspinal hematomas and pneumothorax). Ultrasound, CT
angiography and MR angiography examinations have decreased the indications for
cerebral angiography, whose main complications -in addition to contrast
reactions, hemorrhage and infection at the injection site- are neurological
deficits caused by vascular dissection or atheromatous embolus.
Video-electroencephalogram (EEG) recording with medication suppression can be
used in the presurgical evaluation of epilepsy, which can precipitate repeated
seizures with the risk of injuries and status epilepticus. The possible
complications of studies performed with invasive electrodes are infections and
intracranial hemorrhages. Cerebral biopsy is indicated when treatable disease is
suspected but the therapeutic options (radiotherapy, chemotherapy) have
potential serious adverse effects. Furthermore, cerebral biopsy can aggravate
previous neurological deficits or produce new deficits. Genetic testing is not
indicated in healthy children when an untreatable disease is suspected. In
adults, genetic testing is appropriate in selected cases, but detailed previous
information should be gathered and the possibility of triggering serious
emotional reactions should always be considered. OBJECTIVE: To assess the usage of cranial computed tomography (CT) in patients
admitted with meningitis.
DESIGN: Retrospective study.
SETTING: Heart of England NHS foundation trust, a teaching hospital in the West
Midlands.
PARTICIPANTS: Two groups of adult patients admitted with meningitis between
April 2001 and September 2004 and from September 2006 until September 2009.
MAIN OUTCOME MEASURES: The numbers of patients having cranial CT and lumbar
puncture and whether any complications had arisen following lumbar puncture. The
appropriateness of the CT request according to local criteria.
RESULTS: A total of 111 patients were admitted in the initial time period and 47
patients in the second time period. In the first group, 67 patients underwent CT
(61%), compared with 36 patients (80%) in the second group. There were eight
abnormal scans (12%) in the initial group including three patients with
radiological features of cerebral oedema. Of these patients, one underwent
lumbar puncture and had no neurological sequelae. In the second group, there
were five abnormal scans (14%) with one presenting a contraindication for lumbar
puncture due to mild ventricular dilatation. A lumbar puncture was performed in
this patient without complication. All patients with abnormal scans had clinical
features to suggest raised intracranial pressure. CT scan requests were
considered inappropriate in 26% of patients in the initial study period and 56%
of patients in the second study period.
CONCLUSION: More patients with meningitis are undergoing CT and the number of
inappropriate requests are increasing. There are few abnormal CT scans
presenting a contraindication for lumbar puncture and the majority of these
patients usually have clinical signs to suggest raised intracranial pressure. |
What laboratory abnormalities are commonly seen in patients with COVID-19? | Common laboratory abnormalities among patients with COVID-19 include:
1. Elevated inflammatory markers (e.g., ferritin, C-reactive protein, and erythrocyte sedimentation rate).
2. Elevated aminotransaminase levels (i.e., AST, ALT).
3. Elevated lactate dehydrogenase (LDH) levels.
4. Lymphopenia, leucocytosis.
Abnormalities in coagulation testing (e.g., increased D-Dimers, decreased platelets), elevated procalcitonin levels, and elevated troponin levels have also been reported. The degree of these abnormalities tends to correlate with disease severity. | The Coronavirus Disease (COVID-19) pandemic first broke out in December 2019 in
Wuhan, China, and has now spread worldwide. Laboratory findings have been only
partially described in some observational studies. To date, more comprehensive
systematic reviews of laboratory findings on COVID-19 are missing. We performed
a systematic review with a meta-analysis to assess laboratory findings in
patients with COVID-19. Observational studies from three databases were
selected. We calculated pooled proportions and 95% confidence interval (95% CI)
using the random-effects model meta-analysis. A total of 1106 articles were
identified from PubMed, Web of Science, CNKI (China), and other sources. After
screening, 28 and 7 studies were selected for a systematic review and a
meta-analysis, respectively. Of the 4,663 patients included, the most prevalent
laboratory finding was increased C-reactive protein (CRP; 73.6%, 95% CI
65.0-81.3%), followed by decreased albumin (62.9%, 95% CI 28.3-91.2%), increased
erythrocyte sedimentation rate (61.2%, 95% CI 41.3-81.0%), decreased eosinophils
(58.4%, 95% CI 46.5-69.8%), increased interleukin-6 (53.1%, 95% CI 36.0-70.0%),
lymphopenia (47.9%, 95% CI 41.6-54.9%), and increased lactate dehydrogenase
(LDH; 46.2%, 95% CI 37.9-54.7%). A meta-analysis of seven studies with 1905
patients showed that increased CRP (OR 3.0, 95% CI: 2.1-4.4), lymphopenia (OR
4.5, 95% CI: 3.3-6.0), and increased LDH (OR 6.7, 95% CI: 2.4-18.9) were
significantly associated with severity. These results demonstrated that more
attention is warranted when interpreting laboratory findings in patients with
COVID-19. Patients with elevated CRP levels, lymphopenia, or elevated LDH
require proper management and, if necessary, transfer to the intensive care
unit. OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged
as a global pandemic in early 2020 with rapidly evolving approaches to
diagnosing the clinical illness called coronavirus disease (COVID-19). The
primary objective of this scoping review is to synthesize current research of
the diagnostic accuracy of history, physical examination, routine laboratory
tests, real-time reverse transcription-polymerase chain reaction (rRT-PCR),
immunology tests, and computed tomography (CT) for the emergency department (ED)
diagnosis of COVID-19. Secondary objectives included a synopsis of diagnostic
biases likely with current COVID-19 research as well as corresponding
implications of false-negative and false-positive results for clinicians and
investigators.
METHODS: A Preferred Reporting Items for Systematic Reviews and
Meta-Analyses-Scoping Review (PRISMA-ScR)-adherent synthesis of COVID-19
diagnostic accuracy through May 5, 2020, was conducted. The search strategy was
designed by a medical librarian and included studies indexed by PubMed and
Embase since January 2020.
RESULTS: A total of 1,907 citations were screened for relevance. Patients
without COVID-19 are rarely reported, so specificity and likelihood ratios were
generally unavailable. Fever is the most common finding, while hyposmia and
hypogeusia appear useful to rule in COVID-19. Cough is not consistently present.
Lymphopenia is the mostly commonly reported laboratory abnormality and occurs in
over 50% of COVID-19 patients. rRT-PCR is currently considered the COVID-19
criterion standard for most diagnostic studies, but a single test sensitivity
ranges from 60% to 78%. Multiple reasons for false-negatives rRT-PCR exist,
including sample site tested and disease stage during which sample was obtained.
CT may increase COVID-19 sensitivity in conjunction with rRT-PCR, but guidelines
for imaging patients most likely to benefit are emerging. IgM and IgG serology
levels are undetectable in the first week of COVID-19, but sensitivity (range =
82% to 100%) and specificity (range = 87% to 100%) are promising. Whether
detectable COVID-19 antibodies correspond to immunity remains uswered.
Current studies do not adhere to accepted diagnostic accuracy reporting
standards and likely report significantly biased results if the same tests were
to be applied to general ED populations with suspected COVID-19.
CONCLUSIONS: With the exception of fever and disorders of smell/taste, history
and physical examination findings are unhelpful to distinguish COVID-19 from
other infectious conditions that mimic SARS-CoV-2 like influenza. Routine
laboratory tests are also nondiagnostic, although lymphopenia is a common
finding and other abnormalities may predict severe disease. Although rRT-PCR is
the current criterion standard, more inclusive consensus-based criteria will
likely emerge because of the high false-negative rate of PCR tests. The role of
serology and CT in ED assessments remains undefined. BACKGROUND: In the context of the COVID-19 outbreak of worldwide, we aim to
analyze the laboratory risk factors of in-hospital death in patients with severe
COVID-19.
METHODS: All ≥18-year-old patients with confirmed severe COVID-19 admitted to
Tongji Hospital (Wuhan, China) from February 3 to February 20, 2020, were
retrospectively enrolled and followed up until March 20, 2020. Epidemiological,
clinical, laboratory, and treatment data were collected and explored the risk
factors associated with in-hospital death.
RESULTS: A total of 73 severe patients were enrolled in the study, of whom 20
(27%) patients died in hospital during the average 28 days of follow-up period.
The median age of non-survivors was significantly older than survivors (69
[64-76.5] years vs 64 [56-71.3] years, P = .033) and 15 (75%) patients were
males. The laboratory abnormalities of non-survivors mainly presented in serious
inflammation response and multiple organ failure, with high levels of cytokines
and deranged coagulation parameters. Multivariable regression showed that
neutrophil count greater than 4.47 × 109 /L (OR, 58.35; 95%CI: 2.16-1571.69;
P = .016), hypersensitivity C-reactive protein greater than 86.7 mg/L (OR,
14.90; 95%CI: 1.29-171.10; P = .030), creatine kinase greater than 101 U/L (OR,
161.62; 95%CI: 6.45-4045.20; P = .002), and blood urea nitrogen greater than
6.7 mmol/L (OR, 11.18; 95%CI: 1.36-91.62; P = .024) were risk factors for
in-hospital death.
CONCLUSION: The risk factors of neutrophil count, hypersensitivity C-reactive
protein, creatine kinase, and blood urea nitrogen could help clinicians to early
identify COVID-19 severe patients with poor outcomes on admission. Virus direct
attack and cytokine storm play a major role in the death of COVID-19. Coronavirus disease 2019 (COVID-19) is affecting millions of patients worldwide.
It is caused by the severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2), which belongs to the family Coronaviridae, with 80% genomic
similarities to SARS-CoV. Lymphopenia was commonly seen in infected patients and
has a correlation to disease severity. Thrombocytopenia, coagulation
abnormalities, and disseminated intravascular coagulation were observed in
COVID-19 patients, especially those with critical illness and non-survivors.
This pandemic has caused disruption in communities and hospital services, as
well as straining blood product supply, affecting chemotherapy treatment and
haematopoietic stem cell transplantation schedule. In this article, we review
the haematological manifestations of the disease and its implication on the
management of patients with haematological disorders. BACKGROUND: Clinical observations demonstrated that COVID-19 related pneumonia
is often accompanied by hematological and coagulation abnormalities including
lymphopenia, thrombocytopenia, and prolonged prothrombin time. The evaluation of
laboratory findings including coagulation and inflammation parameters may
represent a promising approach for early determination of COVID-19 severity.
METHODS AND MATERIALS: In the present study, we aimed to identify laboratory
parameters present upon admission in patients with COVID-19 related viral
pneumonia and associated with an early in-hospital development of refractory
respiratory failure or severe acute respiratory distress syndrome requiring
treatment in an intensive care unit. We investigated differences in the
C-reactive protein (CRP) and fibrinogen levels, prothrombin time (PT) and
international normalized ratio (INR) between COVID-19 patients who had been
transferred to an ICU within two weeks after admission (n = 82) and COVID-19
patients with stable course of the disease (n = 74).
RESULTS: Multiple comparisons showed statistically significantly prolonged PT on
admission in ICU-transferred COVID-19 patients (14.15 sec, median, CI 95%
13.4 ÷ 14.9) compared to the stable COVID-19 patients (13.25 sec, median, CI 95%
12.9 ÷ 13.6) (p-value = .0005). CRP levels upon admission were statistically
significantly higher in ICU-transferred COVID-19 patients (132 mg/L, median,
CI95% 113 ÷ 159) compared to the stable COVID-19 patients (51 mg/L, median,
CI95% 33 ÷ 72) (p-value < .0001). On-admission fibrinogen and INR levels did not
statistically significantly differ between ICU-transferred COVID-19 patients and
stable COVID-19 patients.
CONCLUSION: We suggest that CRP and PT levels present on admission in COVID-19
patients may be used as early prognostic markers of severe pneumonia requiring
transfer to ICU. BACKGROUND: COVID-19 is a systemic viral infection which mainly targets the
human respiratory system with many secondary clinical manifestations especially
affecting the hematopoietic system and haemostasis. Few studies have highlighted
the prognostic value of blood findings such as lymphopenia,
neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, LDH, CRP, cardiac
troponin, low-density lipoproteins and chest radiographic abnormality. A study
of progressions of blood and radiological results may help to identify patients
at high risk of severe outcomes. This systematic review aimed to assess the
temporal progression of blood and radiology findings of patients with COVID-19.
METHODS: Comprehensive systematic literature search was conducted on Medline,
Embase and Cochrane databases to identify articles published for peripheral
blood investigation and radiological results of COVID-19 patients.
RESULTS: A total of 27 studies were included in this review. The common
laboratory features reported include lymphopenia, elevated levels of C-reactive
proteins and lactate dehydrogenase. For radiological signs, ground-glass
opacifications, consolidations, and crazy paving patterns were frequently
reported. There is a correlation between lymphocyte count, neutrophil count and
biomarkers such as C-reactive proteins and lactate dehydrogenase; at a later
phase of the disease (more than 7 days since onset of symptoms), lymphopenia
worsens while neutrophil count, C-reactive protein levels and lactate
dehydrogenase levels increase. Frequencies of ground-glass opacifications and
ground-glass opacifications with consolidations decrease at a later phase of the
disease while that of consolidation and crazy paving pattern rises as the
disease progresses. More extensive lung involvement was also seen more
frequently in the later phases.
CONCLUSION: The correlation between temporal progression and the reported blood
and radiological results may be helpful to monitor and evaluate disease
progression and severity. BACKGROUND: Abnormal laboratory findings are common in patients infected with
severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The aim of this
systematic review was to investigate the effect of the level of some laboratory
factors (C-reactive protein (CRP), creatinine, leukocyte count, hemoglobin, and
platelet count) on the severity and outcome of coronavirus disease 2019
(COVID-19).
METHODS: We searched PubMed, Web of Science, Scopus, and Google Scholar. We
collected the articles published before May 26, 2020. We gathered the laboratory
factors in groups of patients with COVID-19, and studied the relation between
level of these factors with severity and outcome of the disease.
RESULTS: Mean CRP level, creatinine, hemoglobin, and the leukocytes count in the
critically ill patients were significantly higher than those of the other groups
(non-critical patients); mean CRP = 54.81 mg/l, mean creatinine = 86.82 μmol/l,
mean hemoglobin = 144.05 g/l, and mean leukocyte count = 7.41 × 109. The
lymphocyte count was higher in patients with mild/moderate disease (mean:
1.32 × 109) and in the invasive ventilation group (mean value of 0.72 × 109),
but it was considerably lower than those of the other two groups. The results
showed that the platelet count was higher in critically ill patients (mean value
of 205.96 × 109). However, the amount was lower in the invasive ventilation
group compared with the other groups (mean level = 185.67 × 109).
CONCLUSION: With increasing disease severity, the leukocyte count and the level
of CRP increase significantly and the lymphocyte count decreases. There seems to
be a significant relation between platelet level, hemoglobin, and creatinine
level with severity of the disease. However, more studies are required to
confirm this. Coronavirus disease 2019 (COVID-19) pandemic continues devastating effects on
healthcare systems. Such a crisis calls for an urgent need to develop a risk
stratification tool. The present chapter aimed to identify laboratory and
clinical correlates of adverse outcomes in patients with COVID-19. To this end,
we conducted a systematic evaluation of studies that investigated laboratory
abnormalities in patients with COVID-19 and compared i. patients with a severe
form of disease and patients with a non-severe form of the disease, ii. patients
who were in critical condition and patients who were not in critical condition,
and iii. patients who survived and patients who died. We included 54 studies in
the data synthesis. Compared to patients with a non-severe form of COVID-19,
patients who had a severe form of disease revealed higher values for white blood
cells (WBC), polymorphonuclear leukocytes (PMN), total bilirubin, alanine
aminotransferase (ALT), creatinine, troponin, procalcitonin, lactate
dehydrogenase (LDH), and D-dimer. By contrast, platelet count, lymphocyte count,
and albumin levels were decreased in patients with a severe form of COVID-19.
Also, patients with a severe phenotype of disease were more likely to have
diabetes, chronic heart disease, chronic obstructive pulmonary disease (COPD),
cerebrovascular disease, hypertension, chronic kidney disease (CKD), and
maligcy. Compared to patients who survived, patients who died had higher WBC,
PMN, total bilirubin, ALT, procalcitonin, IL-6, creatinine, PT, lymphocyte
count, platelet count, and albumin. Also, non-survivors revealed a higher
prevalence of diabetes, chronic heart disease, COPD, cerebrovascular disease,
and CKD. Meta-analyses identified several laboratory parameters that might help
the prediction of severe, critical, and lethal phenotypes of COVID-19. These
parameters correlate with the immune system function, inflammation, coagulation,
and liver and kidney function. Prognostic markers are needed to understand the disease course and severity in
patients with Covid-19. There is evidence that Covid-19 causes gastrointestinal
symptoms and abnormalities in liver enzymes. We aimed to determine if
hepatobiliary laboratory data could predict disease severity in patients with
Covid-19. In this retrospective, single institution, cohort study that analyzed
patients admitted to a community academic hospital with the diagnosis of
Covid-19, we found that elevations of Aspartate Aminotransferase (AST), Alanine
Aminotransferase (ALT) and Alkaline Phosphatase (AP) at any time during hospital
admission increased the odds of ICU admission by 5.12 (95% CI: 1.55-16.89;
p = 0.007), 4.71 (95% CI: 1.51-14.69; p = 0.01) and 4.12 (95% CI: 1.21-14.06,
p = 0.02), respectively. Hypoalbuminemia found at the time of admission to the
hospital was associated with increased mortality (p = 0.02), hypotension
(p = 0.03), and need for vasopressors (p = 0.02), intubation (p = 0.01) and
hemodialysis (p = 0.002). Additionally, there was evidence of liver injury: AST
was significantly elevated above baseline in patients admitted to the ICU
(54.2 ± 15.70 U/L) relative to those who were not (9.2 ± 4.89 U/L; p = 0.01).
Taken together, this study found that hypoalbuminemia and abnormalities in
hepatobiliary laboratory data may be prognostic factors for disease severity in
patients admitted to the hospital with Covid-19. Coronavirus disease 2019 (COVID-19) is the third known animal coronavirus, after
severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome
coronavirus (MERS-CoV). The mean age of the infected patients was estimated to
be between 50 and 69 years old. Accordingly, the COVID-19 mortality rate was
calculated as 15%. In this regard, the essential component of prevention and
planning is knowledge of laboratory and demographic findings among COVID-19
patients; therefore, the present study was conducted to investigate laboratory
and demographic findings among these patients worldwide. This systematic review
was performed on the articles published in English between January 1, 2019 and
May 4, 2020, using MeSH-compliant keywords such as "COVID-19", "Laboratory,
coronavirus disease-19 testing", and " demography " in international databases
(PubMed, and web of science Scopus). Thereafter, the articles relevant to
laboratory and demographic findings among COVID-19 patients were included in the
final review. Reviewing the included articles showed changes in the mean
lymphocytes count ranged from 0.7 to 39 in hospital or severe cases. Moreover,
Leukopenia was not observed in patients with thrombocytopenia. In addition,
C-reactive protein (CRP), leukocytes, D-dimer, FDP, FIB, neutrophils, AST, serum
creatinine, t-troponin, troponin I, and blood bilirubin levels showed increasing
trends in most studies conducted on COVID-19 patients. Notably, the elevated LDH
level was more common among children than adults. According to the results of
the present study, and by considering the clinical characteristics of COVID-19
patients on the one hand, and considering the changes in laboratory samples such
as lymphocytes and other blood markers due to the damaged myocardial, hepatic,
and renal tissues on the other hand, it is recommended to confirm the diagnosis
of this infection by evaluating the patients' blood samples using other
diagnostic methods like lung scan. BACKGROUND: Laboratory parameter abnormalities are commonly observed in COVID-19
patients; however, their clinical significance remains controversial. We
assessed the prevalence, characteristics, and clinical impact of laboratory
parameters in COVID-19 patients hospitalized in Daegu, Korea.
METHODS: We investigated the clinical and laboratory parameters of 1,952
COVID-19 patients on admission in nine hospitals in Daegu, Korea. The average
patient age was 58.1 years, and 700 (35.9%) patients were men. The patients were
classified into mild (N=1,612), moderate (N=294), and severe (N=46) disease
groups based on clinical severity scores. We used chi-square test, multiple
comparison analysis, and multinomial logistic regression to evaluate the
correlation between laboratory parameters and disease severity.
RESULTS: Laboratory parameters on admission in the three disease groups were
significantly different in terms of hematologic (Hb, Hct, white blood cell
count, lymphocyte%, and platelet count), coagulation (prothrombin time and
activated partial thromboplastin time), biochemical (albumin, aspartate
aminotransferase, alanine aminotransferase, lactate, blood urea nitrogen,
creatinine, and electrolytes), inflammatory (C-reactive protein and
procalcitonin), cardiac (creatinine kinase MB isoenzyme and troponin I), and
molecular virologic (Ct value of SARS-CoV-2 RdRP gene) parameters. Relative
lymphopenia, prothrombin time prolongation, and hypoalbuminemia were significant
indicators of COVID-19 severity. Patients with both hypoalbuminemia and
lymphopenia had a higher risk of severe COVID-19.
CONCLUSIONS: Laboratory parameter abnormalities on admission are common, are
significantly associated with clinical severity, and can serve as independent
predictors of COVID-19 severity. Monitoring the laboratory parameters, including
albumin and lymphocyte count, is crucial for timely treatment of COVID-19. BACKGROUND: The aim of this study was to investigate changes in some laboratory
parameters in response to four independent variables (COVID-19, diabetes,
gender, and age) using univariate and multivariate analysis.
METHODS: We measured WBC (neutrophil and lymphocytes), RBC and platelet counts,
and hemoglobin, lactate dehydrogenase, C-reactive protein, IL-2, IL-4, and
vitamin D3 levels in 30 hospitalized patients with severe COVID-19 and in 30
healthy people in terms of COVID-19. The population was divided into groups
based on each of the variables of age, gender, COVID-19, and type 2 diabetes.
Then they were subjected to univariate and multivariate analysis of logistic
regression.
RESULTS: Based on CBC data, leukocytosis (in 70% of COVID-19 patients, 61.1% of
diabetic patients, and 70.9 ± 18 years old), neutrophilia (in 73.3% of patients
with COVID-19, 61.1% of diabetic patients, and 66 ± 18.6 years old), neutropenia
(in 6.7% of patients with COVID-19, 27.8% of diabetic patients, and 33.6 ± 12.7
years old), lymphocytosis (10% of patients with COVID-19, 33.3% of diabetic
patients, and 35.4 ± 15.5 years old), and lymphocytopenia (in 76.7% of patients
with COVID-19, 66.7% of diabetic patients, and 67.1 ± 18.8 years old) were
observed in the population. The elderly and those with COVID-19 had significant
abnormal RBC and platelet counts. Increased LDH and CRP levels and abnormal
hemoglobin level were related to elderly, COVID-19, and diabetes conditions.
Although the levels of IL-2 and -4 were significant in patients with COVID-19
and elderly; however, the changes were not significant in diabetic patients.
Changes in serum vitamin D levels were not significant in any of the sub-groups.
CONCLUSIONS: We showed that leukocytosis, neutrophilia, lymphocytopenia,
abnormal counts of RBCs and platelets, the elevated levels of LDH and CRP, and
abnormal hemoglobin levels in blood are considered as poor prognostic factors
for COVID-19. |
Do only changes in coding regions of MEF2C cause developmental disorders? | No. Non-coding region variants upstream of MEF2C cause severe developmental disorder through three distinct loss-of-function mechanisms. | Author information:
(1)Institute of Biomedical and Clinical Science, University of Exeter Medical
School, Royal Devon & Exeter Hospital, Exeter EX2 5DW, UK.
(2)National Heart & Lung Institute and MRC London Institute of Medical Sciences,
Imperial College London, London W12 0NN, UK; Cardiovascular Research Centre,
Royal Brompton & Harefield Hospitals NHS Trust, London SW3 6NP, UK.
(3)Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029
Madrid, Spain.
(4)Human Genetics Programme, Wellcome Sanger Institute, Wellcome Genome Campus,
Hinxton CB10 1RQ, UK.
(5)National Institute for Health Research Oxford Biomedical Research Centre,
Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
(6)Analytic and Translational Genetics Unit, Massachusetts General Hospital,
Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad
Institute of MIT and Harvard, Cambridge, MA 02142, USA.
(7)European Molecular Biology Laboratory, European Bioinformatics Institute
(EMBL-EBI), Cambridge CB10 1SD, UK.
(8)Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation
Trust, Sheffield S10 2TH, UK; Academic Unit of Child Health, Department of
Oncology & Metabolism, University of Sheffield, Sheffield S10 2TH, UK.
(9)Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester
University Hospitals NHS Foundation Trust, Health Innovation Manchester,
Manchester M13 9WL, UK; Division of Evolution and Genomic Sciences, School of
Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PL,
UK.
(10)Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester
University Hospitals NHS Foundation Trust, Health Innovation Manchester,
Manchester M13 9WL, UK.
(11)Division of Evolution and Genomic Sciences, School of Biological Sciences,
University of Manchester, Oxford Road, Manchester M13 9PL, UK.
(12)Department of Pediatrics, Wake Forest School of Medicine, Winston-Salem, NC
27101, USA.
(13)UCD Academic Centre on Rare Diseases, School of Medicine and Medical
Sciences, University College Dublin, and Clinical Genetics, Temple Street
Children's University Hospital, Dublin D01 XD99, Ireland.
(14)West Midlands Regional Clinical Genetics Service and Birmingham Health
Partners, Birmingham Women's and Children's Hospitals NHS Foundation Trust,
Birmingham B4 6NH, UK.
(15)Department of Pediatrics, Saint Louis University School of Medicine, Saint
Louis, MO 63104, USA.
(16)All Wales Medical Genomics Service, NHS Wales Cardiff and Vale University
Health Board, Institute of Medical Genetics, University Hospital of Wales,
Cardiff CF14 4AY, UK.
(17)Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS
Foundation Trust, Oxford OX3 7LE, UK.
(18)Department of Neurology, University of Kansas School of Medicine-Salina
Campus, Salina, KS 67401, USA.
(19)National Heart & Lung Institute and MRC London Institute of Medical
Sciences, Imperial College London, London W12 0NN, UK.
(20)GeneDx, Gaithersburg, MD 20877, USA.
(21)Human Genetics Programme, Wellcome Sanger Institute, Wellcome Genome Campus,
Hinxton CB10 1RQ, UK; East Anglian Medical Genetics Service, Cambridge
University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK.
(22)Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029
Madrid, Spain; CIBER de enfermedades CardioVasculares (CIBERCV), 28029 Madrid,
Spain.
(23)Human Genetics Programme, Wellcome Sanger Institute, Wellcome Genome Campus,
Hinxton CB10 1RQ, UK; Program in Medical and Population Genetics, Broad
Institute of MIT and Harvard, Cambridge, MA 02142, USA; Wellcome Centre for
Human Genetics, University of Oxford, Oxford OX3 7BN, UK. Electronic address:
[email protected]. |
Which factor is inhibited by Milvexian? | Milvexian is a small molecule, active-site inhibitor of factor XIa (FXIa) being developed to prevent and treat thrombotic events. | Factor XIa (FXIa) is an enzyme in the coagulation cascade thought to amplify
thrombin generation but has a limited role in hemostasis. From preclinical
models and human genetics, an inhibitor of FXIa has the potential to be an
antithrombotic agent with superior efficacy and safety. Reversible and
irreversible inhibitors of FXIa have demonstrated excellent antithrombotic
efficacy without increased bleeding time in animal models (Weitz, J. I., Chan,
N. C. Arterioscler. Thromb. Vasc. Biol. 2019, 39 (1), 7-12). Herein, we report
the discovery of a novel series of macrocyclic FXIa inhibitors containing a
pyrazole P2' moiety. Optimization of the series for (pharmacokinetic) PK
properties, free fraction, and solubility resulted in the identification of
milvexian (BMS-986177/JNJ-70033093, 17, FXIa Ki = 0.11 nM) as a clinical
candidate for the prevention and treatment of thromboembolic disorders, suitable
for oral administration. Milvexian (BMS-986177/JNJ-70033093) is a small molecule, active-site inhibitor
of factor XIa (FXIa) being developed to prevent and treat thrombotic events. The
safety, tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of
milvexian were assessed in a two-part, double-blind, placebo-controlled,
sequential single ascending dose (SAD) and multiple ascending dose (MAD) study
in healthy adults. Participants in SAD panels (6 panels of 8 participants;
n = 48) were randomized (3:1) to receive milvexian (4, 20, 60, 200, 300, or
500 mg) or placebo. The 200- and 500-mg panels investigated the pharmacokinetic
impact of a high-fat meal. Participants in MAD panels (7 panels of 8
participants; n = 56) were randomized (3:1) to receive milvexian (once- or
twice-daily) or placebo for 14 days. All milvexian dosing regimens were safe and
well-tolerated, with only mild treatment-emergent adverse events and no
clinically significant bleeding events. In SAD panels, maximum milvexian plasma
concentration occurred 3 h postdose in all fasted panels. The terminal half-life
(T1/2 ) ranged from 8.3 to 13.8 h. In fasted panels from 20 to 200 mg,
absorption was dose-proportional; results at higher doses (300 and 500 mg) were
consistent with saturable absorption. Food increased milvexian bioavailability
in a dose-dependent fashion. In MAD panels, steady-state milvexian plasma
concentration was reached within 3 and 6 dosing days with once- and twice-daily
dosing, respectively. Renal excretion was less than 20% in all panels.
Prolongation of activated partial thromboplastin time was observed and was
directly related to drug exposure. These results suggest that the safety,
tolerability, PK, and PD properties of milvexian are suitable for further
clinical development. BACKGROUND: Milvexian (BMS-986177/JNJ-70033093) is an orally bioavailable factor
XIa (FXIa) inhibitor currently in phase 2 clinical trials.
OBJECTIVES: To evaluate in vitro properties and in vivo characteristics of
milvexian.
METHODS: In vitro properties of milvexian were evaluated with coagulation and
enzyme assays, and in vivo profiles were characterized with rabbit models of
electrolytic-induced carotid arterial thrombosis and cuticle bleeding time (BT).
RESULTS: Milvexian is an active-site, reversible inhibitor of human and rabbit
FXIa (Ki 0.11 and 0.38 nM, respectively). Milvexian increased activated partial
thromboplastin time (APTT) without changing prothrombin time and potently
prolonged plasma APTT in humans and rabbits. Milvexian did not alter platelet
aggregation to ADP, arachidonic acid, or collagen. Milvexian was evaluated for
in vivo prevention and treatment of thrombosis. For prevention, milvexian
0.063 + 0.04, 0.25 + 0.17, and 1 + 0.67 mg/kg+mg/kg/h preserved 32 ± 6*,
54 ± 10*, and 76 ± 5%* of carotid blood flow (CBF) and reduced thrombus weight
by 15 ± 10*, 45 ± 2*, and 70 ± 4%*, respectively (*p < .05; n = 6/dose). For
treatment, thrombosis was initiated for 15 min and CBF decreased to 40% of
control. Seventy-five minutes after milvexian administration, CBF averaged
1 ± 0.3, 39 ± 10, and 66 ± 2%* in groups treated with vehicle and milvexian
0.25 + 0.17 and 1 + 0.67 mg/kg+mg/kg/h, respectively (*p < .05 vs. vehicle;
n = 6/group). The combination of milvexian 1 + 0.67 mg/kg+mg/kg/h and aspirin
4 mg/kg/h intravenous did not increase BT versus aspirin monotherapy.
CONCLUSIONS: Milvexian is an effective antithrombotic agent with limited impact
on hemostasis, even when combined with aspirin in rabbits. This study supports
inhibition of FXIa with milvexian as a promising antithrombotic therapy with a
wide therapeutic window. BACKGROUND: Factor XIa inhibitors for the prevention and treatment of venous and
arterial thromboembolism may be more effective and result in less bleeding than
conventional anticoagulants. Additional data are needed regarding the efficacy
and safety of milvexian, an oral factor XIa inhibitor.
METHODS: In this parallel-group, phase 2 trial, we randomly assigned 1242
patients undergoing knee arthroplasty to receive one of seven postoperative
regimens of milvexian (25 mg, 50 mg, 100 mg, or 200 mg twice daily or 25 mg, 50
mg, or 200 mg once daily) or enoxaparin (40 mg once daily). The primary efficacy
outcome was venous thromboembolism (which was a composite of asymptomatic
deep-vein thrombosis, confirmed symptomatic venous thromboembolism, or death
from any cause). The principal safety outcome was bleeding.
RESULTS: Among the patients receiving milvexian twice daily, venous
thromboembolism developed in 27 of 129 (21%) taking 25 mg, in 14 of 124 (11%)
taking 50 mg, in 12 of 134 (9%) taking 100 mg, and in 10 of 131 (8%) taking 200
mg. Among those receiving milvexian once daily, venous thromboembolism developed
in 7 of 28 (25%) taking 25 mg, in 30 of 127 (24%) taking 50 mg, and in 8 of 123
(7%) taking 200 mg, as compared with 54 of 252 patients (21%) taking enoxaparin.
The dose-response relationship with twice-daily milvexian was significant
(one-sided P<0.001), and the 12% incidence of venous thromboembolism with
twice-daily milvexian was significantly lower than the prespecified benchmark of
30% (one-sided P<0.001). Bleeding of any severity occurred in 38 of 923 patients
(4%) taking milvexian and in 12 of 296 patients (4%) taking enoxaparin; major or
clinically relevant nonmajor bleeding occurred in 1% and 2%, respectively; and
serious adverse events were reported in 2% and 4%, respectively.
CONCLUSIONS: Postoperative factor XIa inhibition with oral milvexian in patients
undergoing knee arthroplasty was effective for the prevention of venous
thromboembolism and was associated with a low risk of bleeding. (Funded by
Bristol Myers Squibb and Janssen Research and Development; AXIOMATIC-TKR
ClinicalTrials.gov number, NCT03891524.). |
What is Granzyme B? | Granzyme B is a serine protease that is secreted by Natural Killer (NK) cells and cytotoxic T lymphocytes during a cellular immune response and can induce apoptosis. | Granzyme B is known to be a serine protease contained in granules of cytotoxic T
cells. We have previously reported an influence of granzyme B expression in T
regulatory cells (Tregs) on the risk of acute graft versus host disease (GVHD)
onset. However, it is still unknown if conventional T cells (Tcon) use the
granzyme B pathway as a mechanism of alloimmunity. We hypothesized that granzyme
B in Tcon may affect recurrence within the first 6 months after allogeneic
transplantation (allo-HSCT). A total of 65 patients with different hematological
maligcies were included in this study. Blood samples were collected on day
+30 after allo-HSCT. The percentage of granzyme B positive conventional T cells
in patients who developed relapse in the first 6 months after allo-HSCT was 11.3
(4.5-35.3) compared to the others in continuous complete remission-1.3
(3.65-9.7), р = 0.011. The risk of relapse after allo-HSCT was in 3.9 times
higher in patients with an increased percentage of granzyme B positive
conventional T cells. The findings demonstrated that the percentage of granzyme
B positive conventional T cells on day +30 after allo-HSCT could be a
predictable marker of relapse within the first 6 months after allo-HSCT. Kawasaki disease (KD) is a systemic vasculitis of unknown etiology which
predomitly affects medium- and small-sized muscular arteries. Histopathologic
studies of KD vasculitis lesions have demonstrated characteristic T cell
infiltration and an abundance of CD8 T cells; however, the contribution of
cytotoxic lymphocytes to KD vasculitis lesions has not been identified. Here, we
histopathologically and immunohistochemically examined infiltrating inflammatory
cells, particularly cytotoxic protein-positive cells, such as granzyme B cells
and TIA-1 cells, in KD vasculitis lesions. Three autopsy specimens with
acute-phase KD were observed and contained 24 vasculitis lesions affecting
medium-sized muscular arteries, excluding pulmonary arteries. Infiltrating
neutrophils in vasculitis lesions were evaluated by hematoxylin and eosin
staining, and monocytes/macrophages and lymphocytes were evaluated by
immunohistochemistry. The predomit cells were CD163 monocytes/macrophages and
CD3 T cells. CD8 T cells, granzyme B cells, and TIA-1 cells were also observed,
but CD56 natural killer cells were rare. To the best of our knowledge, the
current study is the first histopathologic report confirming the infiltration of
inflammatory cells with cytotoxic proteins in vasculitis lesions in patients
with KD. Cytotoxic T cells may play a role in the development of vasculitis
lesions in KD patients. BACKGROUND: Immune checkpoint inhibitors (ICI) therapies have demonstrated
significant benefit in the treatment of many tumors including high grade
urothelial cancer (HGUC) of the bladder. However, variability in patients'
clinical responses highlights the need for biomarkers to aid patient
stratification. ICI relies on an intact host immune response. In this context,
we hypothesize that key players in the antitumor immune response such as markers
of activated cytotoxic T lymphocytes (CD8, granzyme-B) and immune suppression
(FOXP3) may help to identify patients who will derive the greatest therapeutic
benefit from ICI. A major obstacle for deployment of such a strategy is the
limited quantities of tumor-derived biopsy material. Therefore, in this
technical study, we develop a multiplex biomarker with digital workflow. We
explored the (1) concordance of conventional single stain results using digital
image analysis, and (2) agreement between digital scoring versus manual
analysis.
METHODS: (1) For concordance study of single and multiplex stains, triplicate
core tissue microarrays of 207 muscle invasive, HGUC of bladder had sequential
4-micron sections cut and stained with CD8, FOXP3 and granzyme-B. An inhouse
developed tri-chromogen multiplex immunohistochemistry (m-IHC) assay consisting
of CD8 (green), granzyme B (brown), and FOXP3 (red) was used to stain the next
sequential tissue section. (2) Agreement between manual and digital analysis was
performed on 19 whole slide sections of HGUC cystectomy specimens. All slides
were scanned using Aperio ScanScope AT Digital Scanner at 40X. Quantitative
digital image analysis was performed using QuPath version 0.2.3 open-source
software. Scores from triplicate cores were averaged for each HGUC specimen for
each marker. Intraclass correlation coefficients were used to compare percent
positive cells between the single- and multi-plex assays. Lin's concordance
correlation coefficients were used for manual versus digital analysis.
RESULTS AND CONCLUSIONS: m-IHC offers significant advantages in characterizing
the host immune microenvironment particularly in limited biopsy tissue material.
Utilizing a digital image workflow resulted in significant concordance between
m-IHC and individual single stains (p < 0.001 for all assessments). Moderate to
good agreements were achieved between manual and digital scoring. Our technical
work demonstrated potential uses of multiplex marker in assessing the host
immune status and could be used in conjunction with PD-L1 as a predictor of
response to ICI therapy. To date, the mechanisms of inflammation have been poorly studied in fish of
commercial interest, due to the lack of development of appropriate experimental
models. The current study evaluated a local inflammation triggered by a
polymeric carrageenin mixture (a mucopolysaccharide derived from the red seaweed
Chondrus crispus) in the skin of gilthead seabream (Sparus aurata). Fish were
injected subcutaneously with phosphate-buffered saline (as control) or
λ/κ-carrageenin (1%), and skin samples from the injection sites were collected
1.5, 3 and 6 hr post-injection, processed for inclusion in paraplast and stained
with haematoxylin-eosin, Alcian blue or periodic acid-Schiff. Furthermore,
immunohistochemistry and expression analyses of several cells' markers and
proinflammatory genes were also analysed in samples of the injected sites.
Microscopic results indicated an increased number of skin mucus-secreting cells
and acidophilic granulocytes in the skin of fish studied at 1.5 hr and 3 hr
post-injection with carrageenin, respectively, with respect to the data obtained
in control fish. Otherwise, both the gene expression of the non-specific
cytotoxic cell marker (granzyme B, grb) and the proinflammatory cytokine
(interleukin-1β, il-1β) were up-regulated at 1.5 hr in the skin of fish injected
with carrageenin compared with the control fish, whilst the gene expression of
acidophilic granulocyte markers (NADPH oxidase subunit Phox22 and Phox40, phox22
and phox40) was up-regulated at 3 and 6 hr in the carrageenin group, compared
with the control group. In addition, the gene expression of myeloperoxidase
(mpo) was also up-regulated at 6 hr in the skin of fish injected with
carrageenin in comparison with control samples. The present results indicate the
chronological participation of two important immune cells involved in the
resolution of the inflammation in the skin of gilthead seabream. |
Is CircRNA produced by back splicing of exon, intron or both, forming exon or intron circRNA? | Human transcriptome contains a large number of circular RNAs (circRNAs) that are mainly produced by back splicing of pre-mRNA. | Circular RNAs (circRNAs) belong to a recently re-discovered species of RNA that
emerge during RNA maturation through a process called back-splicing. A
downstream 5' splice site is linked to an upstream 3' splice site to form a
circular transcript instead of a canonical linear transcript. Recent advances in
next-generation sequencing (NGS) have brought circRNAs back into the focus of
many scientists. Since then, several studies reported that circRNAs are
differentially expressed across tissue types and developmental stages, implying
that they are actively regulated and not merely a by-product of splicing. Though
functional studies have shown that some circRNAs could act as miRNA-sponges, the
function of most circRNAs remains unknown. To expand our understanding of
possible roles of circular RNAs, we propose a new pipeline that could fully
characterizes candidate circRNA structure from RNAseq data-FUCHS: FUll
CHaracterization of circular RNA using RNA-Sequencing. Currently, most
computational prediction pipelines use back-spliced reads to identify circular
RNAs. FUCHS extends this concept by considering all RNA-seq information from
long reads (typically >150 bp) to learn more about the exon coverage, the number
of double break point fragments, the different circular isoforms arising from
one host-gene, and the alternatively spliced exons within the same circRNA
boundaries. This new knowledge will enable the user to carry out differential
motif enrichment and miRNA seed analysis to determine potential regulators
during circRNA biogenesis. FUCHS is an easy-to-use Python based pipeline that
contributes a new aspect to the circRNA research. Protein-coding and noncoding genes in eukaryotes are typically expressed as
linear messenger RNAs, with exons arranged colinearly to their genomic order.
Recent advances in sequencing and in mapping RNA reads to reference genomes have
revealed that thousands of genes express also covalently closed circular RNAs.
Many of these circRNAs are stable and contain exons, but are not translated into
proteins. Here, we review the emerging understanding that both, circRNAs
produced by co- and posttranscriptional head-to-tail "backsplicing" of a
downstream splice donor to a more upstream splice acceptor, as well as circRNAs
generated from intronic lariats during colinear splicing, may exhibit
physiologically relevant regulatory functions in eukaryotes. We describe how
circRNAs impact gene expression of their host gene locus by affecting
transcriptional initiation and elongation or splicing, and how they partake in
controlling the function of other molecules, for example by interacting with
microRNAs and proteins. We conclude with an outlook how circRNA dysregulation
affects disease, and how the stability of circRNAs might be exploited in
biomedical applications. In mammals, many classes of noncoding RNAs (ncRNAs) are expressed at a much
higher level in the brain than in other organs. Recent studies have identified a
new class of ncRNAs called circular RNAs (circRNAs), which are produced by
back-splicing and fusion of either exons, introns, or both exon-intron into
covalently closed loops. The circRNAs are also highly enriched in the brain and
increase continuously from the embryonic to the adult stage. Although the
functional significance and mechanism of action of circRNAs are still being
actively explored, they are thought to regulate the transcription of their host
genes and sequestration of miRNAs and RNA binding proteins. Some circRNAs are
also shown to have translation potential to form peptides. The expression and
abundance of circRNAs seem to be spatiotemporally maintained in a normal brain.
Altered expression of circRNAs is also thought to mediate several disorders,
including brain-tumor growth, and acute and chronic neurodegenerative disorders
by affecting mechanisms such as angiogenesis, neuronal plasticity, autophagy,
apoptosis, and inflammation. This review discusses the involvement of various
circRNAs in brain development and CNS diseases. A better understanding of the
circRNA function will help to develop novel therapeutic strategies to treat CNS
complications. Circular RNAs (circRNAs) are an evolutionarily conserved novel class of
non-coding endogenous RNAs (ncRNAs) found in the eukaryotic transcriptome,
originally believed to be aberrant RNA splicing by-products with decreased
functionality. However, recent advances in high-throughput genomic technology
have allowed circRNAs to be characterized in detail and revealed their role in
controlling various biological and molecular processes, the most essential being
gene regulation. Because of the structural stability, high expression,
availability of microRNA (miRNA) binding sites and tissue-specific expression,
circRNAs have become hot topic of research in RNA biology. Compared to the
linear RNA, circRNAs are produced differentially by backsplicing exons or lariat
introns from a pre-messenger RNA (mRNA) forming a covalently closed loop
structure missing 3' poly-(A) tail or 5' cap, rendering them immune to
exonuclease-mediated degradation. Emerging research has identified multifaceted
roles of circRNAs as miRNA and RNA binding protein (RBP) sponges and
transcription, translation, and splicing event regulators. CircRNAs have been
involved in many human illnesses, including cancer and neurodegenerative
disorders such as Alzheimer's and Parkinson's disease, due to their aberrant
expression in different pathological conditions. The functional versatility
exhibited by circRNAs enables them to serve as potential diagnostic or
predictive biomarkers for various diseases. This review discusses the
properties, characterization, profiling, and the diverse molecular mechanisms of
circRNAs and their use as potential therapeutic targets in different human
maligcies. CircRNAs are a subclass of lncRNAs that have been found to be abundantly present
in a wide range of species, including humans. CircRNAs are generally produced by
a noncanonical splicing event called backsplicing that is dependent on the
canonical splicing machinery, giving rise to circRNAs classified into three main
categories: exonic circRNA, circular intronic RNA, and exon-intron circular RNA.
Notably, circRNAs possess functional importance and display their functions
through different mechanisms of action including sponging miRNAs, or even being
translated into functional proteins. In addition, circRNAs also have great
potential as biomarkers, particularly in cancer, thanks to their high stability,
tissue type and developmental stage specificity, and their presence in
biological fluids, which make them promising candidates as noninvasive
biomarkers. In this chapter, we describe the most commonly used techniques for
the study of circRNAs as cancer biomarkers, including high-throughput techniques
such as RNA-Seq and microarrays, and other methods to analyze the presence of
specific circRNAs in patient samples. |
How does condensin affect the function of topoisomeraseII? | Condensin prevents deleterious anaphase bridges during chromosome segregation by promoting sister chromatid decatenation. | Assembly of compact mitotic chromosomes and resolution of sister chromatids are
two essential processes for the correct segregation of the genome during
mitosis. Condensin, a five-subunit protein complex, is thought to be required
for chromosome condensation. However, recent genetic analysis suggests that
condensin is only essential to resolve sister chromatids. To study further the
function of condensin we have depleted DmSMC4, a subunit of the complex, from
Drosophila S2 cells by dsRNA-mediated interference. Cells lacking DmSMC4
assemble short mitotic chromosomes with unresolved sister chromatids where
Barren, a non-SMC subunit of the complex is unable to localise. Topoisomerase
II, however, binds mitotic chromatin after depletion of DmSMC4 but it is no
longer confined to a central axial structure and becomes diffusely distributed
all over the chromatin. Furthermore, cell extracts from DmSMC4 dsRNA-treated
cells show significantly reduced topoisomerase II-dependent DNA decatenation
activity in vitro. Nevertheless, DmSMC4-depleted chromosomes have centromeres
and kinetochores that are able to segregate, although sister chromatid arms form
extensive chromatin bridges during anaphase. These chromatin bridges do not
result from inappropriate maintece of sister chromatid cohesion by DRAD21, a
subunit of the cohesin complex. Moreover, depletion of DmSMC4 prevents premature
sister chromatid separation, caused by removal of DRAD21, allowing cells to exit
mitosis with chromatin bridges. Our results suggest that condensin is required
so that an axial chromatid structure can be organised where topoisomerase II can
effectively promote sister chromatid resolution. Previous studies of Epstein-Barr virus (EBV) replication focused mainly on the
viral and cellular factors involved in replication compartment assembly and
controlling the cell cycle. However, little is known about how EBV reorganizes
nuclear architecture and the chromatin territories. In EBV-positive
nasopharyngeal carcinoma NA cells or Akata cells, we noticed that cellular
chromatin becomes highly condensed upon EBV reactivation. In searching for the
possible mechanisms involved, we found that transient expression of EBV BGLF4
kinase induces unscheduled chromosome condensation, nuclear lamina disassembly,
and stress fiber rearrangements, independently of cellular DNA replication and
Cdc2 activity. BGLF4 interacts with condensin complexes, the major components in
mitotic chromosome assembly, and induces condensin phosphorylation at Cdc2
consensus motifs. BGLF4 also stimulates the decatenation activity of
topoisomerase II, suggesting that it may induce chromosome condensation through
condensin and topoisomerase II activation. The ability to induce chromosome
condensation is conserved in another gammaherpesvirus kinase, murine herpesvirus
68 ORF36. Together, these findings suggest a novel mechanism by which
gammaherpesvirus kinases may induce multiple premature mitotic events to provide
more extrachromosomal space for viral DNA replication and successful egress of
nucleocapsid from the nucleus. The compaction of chromatin that occurs when cells enter mitosis is probably the
most iconic process of dividing cells. Mitotic chromosomal compaction or
'condensation' is functionally linked to resolution of chromosomal intertwines,
transcriptional shut-off and complete segregation of chromosomes. At present,
understanding of the molecular events required to convert interphase chromatin
into mitotic chromosomes is limited. Here, we review recent advances in the
field, focusing on potential chromosomal compaction mechanisms and their
importance to chromosome segregation. We propose a model of how metaphase
chromosomes could be shaped based on the enzymatic activities of condensin and
topoisomerase II in overwinding and relaxation of the DNA fiber during mitosis.
We suggest that condensin overwinding is an important requirement for intertwine
resolution by topoisomerase II and, together with the inhibition of
transcription, contributes to cytological mitotic chromosome appearance or
'condensation'. Fragile sites are loci of recurrent chromosome breakage in the genome. They are
found in organisms ranging from bacteria to humans and are implicated in genome
instability, evolution, and cancer. In budding yeast, inactivation of Mec1, a
homolog of mammalian ATR, leads to chromosome breakage at fragile sites referred
to as replication slow zones (RSZs). RSZs are proposed to be homologous to
mammalian common fragile sites (CFSs) whose stability is regulated by ATR.
Perturbation during S phase, leading to elevated levels of stalled replication
forks, is necessary but not sufficient for chromosome breakage at RSZs or CFSs.
To address the nature of additional event(s) required for the break formation,
we examined involvement of the currently known or implicated mechanisms of
endogenous chromosome breakage, including errors in replication fork restart,
premature mitotic chromosome condensation, spindle tension, anaphase, and
cytokinesis. Results revealed that chromosome breakage at RSZs is independent of
the RAD52 epistasis group genes and of TOP3, SGS1, SRS2, MMS4, or MUS81,
indicating that homologous recombination and other recombination-related
processes associated with replication fork restart are unlikely to be involved.
We also found spindle force, anaphase, or cytokinesis to be dispensable. RSZ
breakage, however, required genes encoding condensin subunits (YCG1, YSC4) and
topoisomerase II (TOP2). We propose that chromosome break formation at RSZs
following Mec1 inactivation, a model for mammalian fragile site breakage, is
mediated by internal chromosomal stress generated during mitotic chromosome
condensation. The condensin complex is a key determit of mitotic chromosome architecture.
In addition, condensin promotes resolution of sister chromatids during anaphase,
a function that is conserved from prokaryotes to human. Anaphase bridges
observed in cells lacking condensin are reminiscent of chromosome segregation
failure after inactivation of topoisomerase II (topo II), the enzyme that
removes catees persisting between sister chromatids following DNA
replication. Circumstantial evidence has linked condensin to sister chromatid
decatenation but, because of the difficulty of observing chromosome catenation,
this link has remained indirect. Alternative models for how condensin
facilitates chromosome resolution have been put forward. Here, we follow the
catenation status of circular minichromosomes of three sizes during the
Saccharomyeces cerevisiae cell cycle. Catees are produced during DNA
replication and are for the most part swiftly resolved during and following
S-phase, aided by sister chromatid separation. Complete resolution, however,
requires the condensin complex, a dependency that becomes more pronounced with
increasing chromosome size. Our results provide evidence that condensin prevents
deleterious anaphase bridges during chromosome segregation by promoting sister
chromatid decatenation. |
Which signaling pathway does LY294002 inhibit? | LY294002, can block the PI3K/AKT signaling pathway. | Internal tandem duplications (ITD) mutation within FMS-like tyrosine kinase
3 (FLT3), the most frequent mutation happens in almost 20% acute myeloid
leukemia (AML) patients, always predicts a poor prognosis. As a small molecule
tyrosine kinase inhibitor, sorafenib is clinically used for the treatment of
advanced renal cell carcinoma (RCC), hepatocellular carcinoma (HCC), and
differentiated thyroid cancer (DTC), with its preclinical and clinical activity
demonstrated in the treatment of Fms-like tyrosine kinase 3-internal tandem
duplication (FLT3-ITD) mutant AML. Even though it shows a rosy future in the AML
treatment, the short response duration remains a vital problem that leads to
treatment failure. Rapid onset of drug resistance is still a thorny problem that
we cannot overlook. Although the mechanisms of drug resistance have been studied
extensively in the past years, there is still no consensus on the exact reason
for resistance and without effective therapeutic regimens established
clinically. My previous work reported that sorafenib-resistant FLT3-ITD mutant
AML cells displayed mitochondria dysfunction, which rendered cells depending on
glycolysis for energy supply. In my present one, we further illustrated that
losing the target protein FLT3 and the continuously activated PI3K/Akt signaling
pathway may be the reason for drug resistance, with sustained activation of
PI3K/AKT signaling responsible for the highly glycolytic activity and adenosine
triphosphate (ATP) generation. PI3K inhibitor, LY294002, can block PI3K/AKT
signaling, further inhibit glycolysis to disturb ATP production, and finally
induce cell apoptosis. This finding would pave the way to remedy the FLT3-ITD
mutant AML patients who failed with FLT3 targeted therapy. |
Is METTL1 overexpression associated with better patient survival? | No. METTL1 is frequently amplified and overexpressed in cancers and is associated with poor patient survival. | Author information:
(1)Stem Cell Program, Division of Hematology/Oncology, Boston Children's
Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and
Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
(2)Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton,
Cambridge CB10 1SA, UK; Milner Therapeutics Institute, University of Cambridge,
Puddicombe Way, Cambridge CB2 0AW, UK; Storm Therapeutics Ltd., Moneta Building
(B280), Babraham Research Campus, Cambridge CB22 3AT, UK.
(3)Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton,
Cambridge CB10 1SA, UK.
(4)Department of Pathology, Cancer Center, Beth Israel Deaconess Medical Center,
Boston, MA 02115, USA.
(5)Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton,
Cambridge CB10 1SA, UK; Karaiskakio Foundation, Nicandrou Papamina Avenue, 2032
Nicosia, Cyprus.
(6)Division of Newborn Medicine and Epigenetics Program, Department of Medicine,
Boston Children's Hospital, Boston, MA 02115, USA.
(7)Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton,
Cambridge CB10 1SA, UK; Cambridge Institute of Therapeutic Immunology &
Infectious Disease (CITIID), University of Cambridge, Puddicombe Way, Cambridge
CB2 0AW, UK.
(8)Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA
02115, USA.
(9)Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA
02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115,
USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA.
(10)Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge
CB2 1EW, UK.
(11)Department of Biological Chemistry and Molecular Pharmacology, Harvard
Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber
Cancer Institute, Boston, MA 02115, USA.
(12)Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID),
University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK.
(13)Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton,
Cambridge CB10 1SA, UK; Karaiskakio Foundation, Nicandrou Papamina Avenue, 2032
Nicosia, Cyprus; Wellcome-MRC Cambridge Stem Cell Institute, University of
Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK.
(14)Department of Pathology, Cancer Center, Beth Israel Deaconess Medical
Center, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138,
USA; Harvard Initiative for RNA Medicine, Boston, MA 02115, USA.
(15)Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton,
Cambridge CB10 1SA, UK; Milner Therapeutics Institute, University of Cambridge,
Puddicombe Way, Cambridge CB2 0AW, UK; Wellcome-MRC Cambridge Stem Cell
Institute, University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK.
Electronic address: [email protected].
(16)Stem Cell Program, Division of Hematology/Oncology, Boston Children's
Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and
Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Division
of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA;
Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Harvard
Stem Cell Institute, Cambridge, MA 02138, USA; Harvard Initiative for RNA
Medicine, Boston, MA 02115, USA. Electronic address:
[email protected]. |
List monoclonal antibodies included in the REGEN-COV. | REGEN-COV is a combination of the monoclonal antibodies casirivimab and imdevimab. It has been shown to markedly reduce the risk of hospitalization or death among high-risk persons with coronavirus disease 2019. | IMPORTANCE: Easy-to-administer antiviral treatments may be used to prevent
progression from asymptomatic infection to COVID-19 and to reduce viral
carriage.
OBJECTIVE: Evaluate the efficacy and safety of subcutaneous casirivimab and
imdevimab antibody combination (REGEN-COV) to prevent progression from early
asymptomatic SARS-CoV-2 infection to COVID-19.
DESIGN: Randomized, double-blind, placebo-controlled, phase 3 study that
enrolled asymptomatic close contacts living with a SARS-CoV-2-infected household
member (index case). Participants who were SARS-CoV-2 RT-qPCR-positive at
baseline were included in the analysis reported here.
SETTING: Multicenter trial conducted at 112 sites in the United States, Romania,
and Moldova.
PARTICIPANTS: Asymptomatic individuals ≥12 years of age were eligible if
identified within 96 hours of collection of the index case's positive SARS-CoV-2
test sample.
INTERVENTIONS: A total of 314 asymptomatic, SARS-CoV-2 RT-qPCR-positive
individuals living with an infected household contact were randomized 1:1 to
receive a single dose of subcutaneous REGEN-COV 1200mg (n=158) or placebo
(n=156).
MAIN OUTCOMES AND MEASURES: The primary endpoint was the proportion of
participants who developed symptomatic COVID-19 during the 28-day efficacy
assessment period. The key secondary efficacy endpoints were the number of weeks
of symptomatic SARS-CoV-2 infection and the number of weeks of high viral load
(>4 log10 copies/mL). Safety was assessed in all treated participants.
RESULTS: Subcutaneous REGEN-COV 1200mg significantly prevented progression from
asymptomatic to symptomatic disease compared with placebo (31.5% relative risk
reduction; 29/100 [29.0%] vs 44/104 [42.3%], respectively; P=.0380). REGEN-COV
reduced the overall population burden of high-viral load weeks (39.7% reduction
vs placebo; 48 vs 82 total weeks; P=.0010) and of symptomatic weeks (45.3%
reduction vs placebo; 89.6 vs 170.3 total weeks; P=.0273), the latter
corresponding to an approximately 5.6-day reduction in symptom duration per
symptomatic participant. Six placebo-treated participants had a COVID-19-related
hospitalization or ER visit versus none for those receiving REGEN-COV. The
proportion of participants receiving placebo who had ≥1 treatment-emergent
adverse events was 48.1% compared with 33.5% for those receiving REGEN-COV,
including events related (39.7% vs 25.8%, respectively) or not related (16.0% vs
11.0%, respectively) to COVID-19.
CONCLUSIONS AND RELEVANCE: Subcutaneous REGEN-COV 1200mg prevented progression
from asymptomatic SARS-CoV-2 infection to COVID-19, reduced the duration of high
viral load and symptoms, and was well tolerated.
TRIAL REGISTRATION: ClinicalTrials.gov Identifier, NCT04452318. BACKGROUND: Casirivimab and imdevimab (REGEN-COV™) markedly reduces risk of
hospitalization or death in high-risk individuals with Covid-19. Here we explore
the possibility that subcutaneous REGEN-COV prevents SARS-CoV-2 infection and
subsequent Covid-19 in individuals at high risk of contracting SARS-CoV-2 by
close exposure in a household with a documented SARS-CoV-2-infected individual.
METHODS: Individuals ≥12 years were enrolled within 96 hours of a household
contact being diagnosed with SARS-CoV-2 and randomized 1:1 to receive 1200 mg
REGEN-COV or placebo via subcutaneous injection. The primary efficacy endpoint
was the proportion of participants without evidence of infection (SARS-CoV-2
RT-qPCR-negative) or prior immunity (seronegative) who subsequently developed
symptomatic SARS-CoV-2 infection during a 28-day efficacy assessment period.
RESULTS: Subcutaneous REGEN-COV significantly prevented symptomatic SARS-CoV-2
infection compared with placebo (81.4% risk reduction; 11/753 [1.5%] vs. 59/752
[7.8%], respectively; P<0.0001), with 92.6% risk reduction after the first week
(2/753 [0.3%] vs. 27/752 [3.6%], respectively). REGEN-COV also prevented overall
infections, either symptomatic or asymptomatic (66.4% risk reduction). Among
infected participants, the median time to resolution of symptoms was 2 weeks
shorter with REGEN-COV vs. placebo (1.2 vs. 3.2 weeks, respectively), and the
duration of time with high viral load (>104 copies/mL) was lower (0.4 vs. 1.3
weeks, respectively). REGEN-COV was generally well tolerated.
CONCLUSIONS: Administration of subcutaneous REGEN-COV prevented symptomatic
Covid-19 and asymptomatic SARS-CoV-2 infection in uninfected household contacts
of infected individuals. Among individuals who became infected, REGEN-COV
reduced the duration of symptomatic disease, decreased maximal viral load, and
reduced the duration of detectable virus.(ClinicalTrials.gov number,
NCT04452318.). Collaborators: Warshoff N, Moreiras L, Altamirano D, Ellington D, Faikih F,
Smith W, Gibson R, Buckner K, Rosen R, Sapp A, Kohli A, McIntyre V, Sachdeva Y,
McFarland A, Gibson D, Kim K, Ahn J, Neinchel L, Paryani N, Mottola A, Day E,
Navarro M, Victoria R, Victoria X, Uong R, Sampson M, Polk C, Leonard M, McCurdy
L, Medaris LA, Shahid Z, Davidson L, Nazir J, Lee J, Elliott A, Sathyanaryan S,
Oberoi M, Siddiqui M, Arsad M, Bruning K, Hosek S, Oyedele T, Sarda V, Mercon M,
Stephenson K, Barouch D, Juelg B, Tan CS, Zash R, Collier AR, Ansel J, Jaegle K,
Roque-Guerrero L, Gomez Ramirez A, Capote J, Paz G, Paasche-Orlow M, Dedier J,
Vadgama S, Patak R, Chronos N, Hefty C, Borger J, Momodu I, Carswell L, King B,
Starr R, Syndergaard S, Patel N, Patel R, Sattar R, Mohseni R, Unger J, De
Jesus-Mara S, Casaclang C, Seep M, Brown C, Whatley J, Levinson D, Alvi S,
James N, Ahmed A, Koilpillai R, Cassady S, Cox J, Torres E, Krainson J,
Rosenthal MJ, Winnie M, Plemons J, Verma O, Leggett R, Reyes R, Beck K, Poliquin
B, Mussaji M, Shah J, Sutton D, Pereira E, Gloria R, Kelly S, Dennis-Saltz A,
Sheikh-Ali M, Saikali E, Magee J, Goldfaden R, Boghara H, Patel S, Eichelbaum B,
Anderson D, Su S, Akhavan A, Kirby D, Venglik J, Mayer K, Khan T, Gelman M,
Fakih FA, Fakih FM, Layish D, Alvarado F, Diaz J, Focil A, Rosas G, Correa S,
Bogseth M, Patel B, Tarshis G, Grablin K, Simonelli P, Martin S, Sharma A, Chen
A, Dhaubhadel P, Khan S, Naik S, Penupolu S, Sivarajah T, Kwon TS, Saladi L,
Raiszadeh F, Myint KT, Kyaw A, Dowie D, O'Reilly R, Varghese L, Bratu S,
Assallum H, Weerasinghe AT, Ayinla R, Mannheimer S, Morrison E, Franks J,
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Leiman D, Price T, Krasko A, Wiener I, Reed L, Lin O, Ramesh M, Alangaden G,
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McBride V, Aberg J, Cespedes M, Abrams-Downey A, Kojic E, Lugo L, Liu S, Salomon
N, Perlman D, Altman D, Rahman F, Osorio G, Mathew J, Koshy S, Mazo D, Cossarini
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Bihoi G, Ghita A, Miron V, Spataru G, Nyaku A, Swaminathan S, Chang T, Traylor
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Bershteyn A, Raabe V, Davis T, Olson M, Brill S, Malvestutto C, Koletar S,
Saigal T, Sobhanie M, Doraiswamy V, Hassan MA, Young J, DeJesus E, Rolle CP,
Hinestrosa F, Cruz D, Wilder T, Garrett J, Skipper S, Dandillaya R, Ath K,
Frank I, Koenig H, Donaghy E, Dunbar D, Killion J, Amin R, Basener S, Lowry T,
Cannon K, Chadwick M, Galvez O, Castillo F, Jefferies J, Arnold S, Thacker A,
Cordasco E, Zeno B, Holmes H, Lee H, Gaibu N, Cojocaru V, Seremet A, Iacob S,
Usatii R, Ghicavii N, Coltuclu A, Bujor O, Mylonakis E, Farmakiotis D, Tashima
K, Ryback N, Ruane P, Wolfe P, Trinidad K, Moy J, Shah R, Sindhura B, Sha B,
Savant M, Hsiao F, Yee E, Gordillo M, Bhattacharyya R, Tallapragada S, Artau A,
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A, Klein A, Poutsiaka D, Viau Colindres R, Chow B, Thorpe C, Hopkins M, Chow J,
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T, Mendoza C, Mostafavi S, Cano Guerra CA, Dabenigno P, Malla B, Fusco D, Drouin
A, Denson J, Zifodya J, Bojanowski C, Dietrich M, Drury S, Herrick J, Novak R,
Patel M, Acloque G, Martinez A, Sethi S, Clemency B, Kunadharaju R,
Parthasarathy S, Rischard F, Cohen S, Thompson G, Nguyen H, Crabtree S,
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H, Benamu E, Baduashvili A, Krsak M, Johnson S, Chauhan L, Fredregil E, Economos
S, Kleiner G, Abbo L, Shukla B, Gebbia J, Rodriguez M, Leuck AM, Abassi M,
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W 2nd, Tompkins K, Kim K, Lakshmi S, Somboonwit C, Wilson J, Oxner A, Vasey T,
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Marie C, Shirley DA, Carpenter R, Madden G, Donigan D, Sutton M, Edwards C,
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McElrath J, Maenza J, Shapiro A, Stankiewicz-Karita H, Chu H, Church C, Hartman
W, Connor J, Striker R, Philley J, Devine M, Yates R, Hickerson S, Kalams S,
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M, MacLaren L, Goldstein D, Eggleston A, Koebele C, McKenzie M, Deese T, Thomas
B, Tsakiris L, Blank S, Mirenda R, Martin A, Gharat G, Kokaram C, Wray K, Partap
C, Arzamasova U, Louissaint K, Ferdez M, Chani A, Adepoju A, Mahmood A,
Mortagy A, Dupljak A, Baum A, Brown A, Froment A, Hooper A, Margiotta A,
Bombardier A, Islam A, Smith A, Dhillon A, McMillian A, Breazna A, Aslam A,
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Kyratsous CA, Baum C, McDonald C, Leigh C, Pan C, Wolken D, Manganello D, Liu D,
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D, Kennedy D, Darcy D, Barron D, Hughes D, Rofail D, Kaur D, Ramesh D, Bianco D,
Cohen D, Forleo Neto E, Jean-Baptiste E, Bukhari E, Doyle E, Bucknam E,
Labriola-Tomkins E, Nanna E, O'Keefe EH, Gasparino E, Fung E, Isa F, To FY,
Herman G, Yancopoulos GD, Bellingham G, Sumner G, Moggan G, Power G, Zeng H,
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J, Rusconi J, Austin J, Parrino J, Yo J, McDonnell J, Hamilton JD, Boarder J,
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K, Browning K, Rutkowski K, Yau K, Woloshin K, Lewis-Amezcua K, Turner K,
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N, Stahl N, Deitz N, Memblatt N, Shah N, Kumar N, Herrera O, Adedoyin O, Yellin
O, Snodgrass P, Floody P, D'Ambrosio P, Gao P, Hou P, Hearld P, Li Q, Kitchenoff
R, Ali R, Iyer R, Chava R, Alaj R, Pedraza R, Hamlin R, Hosain R, Gorawala R,
White R, Yu R, Fogarty R, Dass SB, Bollini S, Ganguly S, DeCicco S, Patel S,
Cassimaty S, Somersan-Karakaya S, McCarthy S, Henkel S, Ali S, Geila Shapiro S,
Kim S, Nossoughi S, Bisulco S, Elkin S, Long S, Sivapalasingam S, Irvin S, Wilt
S, Min T, Constant T, Devins T, DiCioccio T, Norton T, Bernardo T, Chuang TC,
Wei V, Nuce V, Battini V, Caldwell W, Gao X, Chen X, Tian Y, Khan Y, Zhao Y, Kim
Y, Dye B, Hurt CB, Burwen DR, Barouch DH, Burns D, Brown E, Bar KJ, Marovich M,
Clement M, Cohen MS, Sista N, Barnabas RV, Zwerski S. Regulatory authorities, including the US Food and Drug Administration (FDA),
have accelerated diagnostic and therapeutic approvals during the coronavirus
disease 2019 (COVID-19) pandemic. Accelerated clinical development and approvals
have resulted in vaccine programs for severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2). However, some individuals remain at high risk for
the progression of COVID-19. In the US, the FDA has given Emergency Use
Authorization (EUA) for two neutralizing therapeutic monoclonal antibody
'cocktails,' casirivimab and imdevimab (REGEN-COV), bamlanivimab and etesevimab,
and one monotherapy, bamlanivimab, for prophylactic post-exposure therapy in
individuals at high risk of progressing to severe COVID-19. Preclinical and
clinical studies showed consistent effectiveness of REGEN-COV against current
variants of SARS-CoV-2. On 21st November 2020, the FDA approved an initial EUA
for REGEN-COV to treat mild to moderate COVID-19 in adults and in children 12
years or older with exposure to SARS-CoV-2 at high risk for progression to
severe COVID-19. On 30th July 2021, the FDA updated its EUA for REGEN-COV for
emergency use as post-exposure prophylactic to prevent COVID-19 progression in
adults and children aged 12 years or older. This Editorial aims to provide an
update on accelerated regulatory authorization for post-exposure prophylactic
neutralizing monoclonal antibodies to SARS-CoV-2 for individuals at high risk
for COVID-19. The emergency use authorization for REGEN-COV (a combination of two monoclonal
antibodies, casirivimab and imdevimab) has been revised to include postexposure
prophylaxis of COVID-19 in adults and children 12 years of age and older who, if
they become COVID-19 positive, are at high risk for severe disease.Prophylaxis
with REGEN-COV is not a substitute for vaccination against COVID-19. |
Which disease is caused by mutations in the gene PRF1? | The presence of mutations in PRF1, UNC13D, STX11 and STXBP2 genes in homozygosis or compound heterozygosis results in immune deregulation. Most such cases lead to clinical manifestations of haemophagocytic lymphohistiocytosis (HLH). | Author information:
(1)Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Jeffrey
Model Foundation Excellence Center, Barcelona, Catalonia, Spain.
(2)Immune Regulation and Immunotherapy Group, CIBBIM-Nanomedicine, Vall d'Hebron
Institut de Recerca, Universitat Autonoma de Barcelona, Barcelona, Spain.
(3)Functional Unit of Clinical Immunology and Primary Immunodeficiencies,
Allergy and Clinical Immunology Department, Hospital Sant Joan de Déu,
University of Barcelona, Pediatric Research Institute Sant Joan de Déu,
Barcelona, Spain.
(4)Research Unit in Translational Bioinformatics in Neurosciences, Universitat
Autònoma de Barcelona, Barcelona, Spain.
(5)Hematology Department, Hospital Sant Joan de Déu, Universitat de Barcelona,
Barcelona, Spain.
(6)Institut de Recerca Hospital Sant Joan de Déu Barcelona, Barcelona, Spain.
(7)Diagnostic Immunology Research Group, Vall d'Hebron Research Institute
(VHIR), Barcelona, Catalonia, Spain.
(8)Department of Cell Biology, Physiology and Immunology, Autonomous University
of Barcelona (UAB), Barcelona, Catalonia, Spain.
(9)Genetics Department, Hospital Universitari Vall d'Hebron (HUVH), Barcelona,
Catalonia, Spain.
(10)Institut Catala per la Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
(11)Immune Regulation and Immunotherapy Group, CIBBIM-Nanomedicine, Vall
d'Hebron Institut de Recerca, Universitat Autonoma de Barcelona, Barcelona,
Spain. [email protected].
(12)Institut de Recerca Vall hebron (VHIR), Immune Regulation and Immunotherapy
Group, Edifici Mediterrania, Lab 09, Planta baixa, Passeig Vall d'Hebron
119-129, 08035, Barcelona, Spain. [email protected].
(13)Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Jeffrey
Model Foundation Excellence Center, Barcelona, Catalonia, Spain.
[email protected].
(14)Diagnostic Immunology Research Group, Vall d'Hebron Research Institute
(VHIR), Barcelona, Catalonia, Spain. [email protected].
(15)Department of Cell Biology, Physiology and Immunology, Autonomous University
of Barcelona (UAB), Barcelona, Catalonia, Spain. [email protected]. BACKGROUND: Familial hemophagocytic lymphohistiocytosis (FHL) is a primary
immunodefici-ency disease caused by gene defects. The onset of FHL in
adolescents and adults may lead clinicians to ignore or even misdiagnose the
disease. To the best of our knowledge, this is the first report to detail the
clinical features of type 2 FHL (FHL2) with compound heterozygous perforin
(PRF1) defects involving the c.163C>T mutation, in addition to correlation
analysis and a literature review.
CASE SUMMARY: We report a case of a 27-year-old male patient with FHL2, who was
admitted with a persistent fever and pancytopenia. Through next-generation
sequencing technology of hemophagocytic lymphohistiocytosis (HLH)-related genes,
we found compound heterozygous mutations of PRF1: c.65delC (p.Pro22Argfs*29)
(frameshift mutation, paternal) and c.163C>T (p.Arg55Cys) (missense mutation,
maternal). Although he did not receive hematopoietic stem cell transplantation,
the patient achieved complete remission after receiving HLH-2004 treatment
protocol. To date, the patient has stopped taking drugs for 15 mo, is in a
stable condition, and is under follow-up observation.
CONCLUSION: The delayed onset of FHL2 may be related to the PRF1 mutation type,
pathogenic variation pattern, triggering factors, and the temperature
sensitivity of some PRF1 mutations. For individual, the detailed reason for the
delay in the onset of FHL warrants further investigation. |
What protein is encoded by the GRN gene? | Loss-of-function mutations in the gene encoding for the protein progranulin (PGRN), GRN, are one of the major genetic abnormalities involved in frontotemporal lobar degeneration. | Progranulin is a growth factor involved in the regulation of multiple processes
including tumorigenesis, wound repair, development, and inflammation. The recent
discovery that mutations in the gene encoding for progranulin (GRN) cause
frontotemporal lobar degeneration (FTLD), and other neurodegenerative diseases
leading to dementia, has brought renewed interest in progranulin and its
functions in the central nervous system. GRN null mutations cause protein
haploinsufficiency, leading to a significant decrease in progranulin levels that
can be detected in plasma, serum and cerebrospinal fluid (CSF) of mutation
carriers. The dosage of circulating progranulin sped up the identification of
GRN mutations thus favoring genotype-phenotype correlation studies. Researchers
demonstrated that, in GRN null mutation carriers, the shortage of progranulin
invariably precedes clinical symptoms and thus mutation carriers are "captured"
regardless of their disease status. GRN is a particularly appealing gene for
drug targeting, in the way that boosting its expression may be beneficial for
mutation carriers, preventing or delaying the onset of GRN-related
neurodegenerative diseases. Physiological regulation of progranulin expression
level is only partially known. Progranulin expression reflects mutation status
and, intriguingly, its levels can be modulated by some additional factor (i.e.
genetic background; drugs). Thus, factors increasing the production and
secretion of progranulin from the normal gene are promising potential
therapeutic avenues. In conclusion, peripheral progranulin is a nonintrusive
highly accurate biomarker for early identification of mutation carriers and for
monitoring future treatments that might boost the level of this protein. Understanding of frontotemporal lobar degeneration, the underlying pathology
most often linked to the clinical diagnosis of frontotemporal dementia, is
rapidly increasing. Mutations in 7 known genes (MAPT, GRN, C9orf72, VCP, CHMP2B,
and, rarely, TARDBP and FUS) are associated with frontotemporal dementia, and
the pathologic classification of frontotemporal lobar degeneration has recently
been modified to reflect these discoveries. Mutations in one of these genes
(GRN), which encodes progranulin, have been implicated in up to a quarter of
cases of frontotemporal lobar degeneration with TDP-43 (TAR DNA-binding protein
43)-positive inclusions; currently, there are more than 60 known pathogenic
mutations of the gene. We present the clinical, pathologic, and genetic findings
on 6 cases from 4 families, 5 of which were shown to have a novel GRN
c.708+6_+9delTGAG mutation. GRN, the gene coding for the progranulin (PGRN) protein, was recognized as a
gene linked to frontotemporal lobar degeneration (FTLD). The first mutations
identified were null mutations giving rise to haploinsufficiency. Missense
mutations were subsequently detected, but only a small subset has been
functionally investigated. We identified missense mutations (C105Y, A199V, and
R298H) in FTLD cases with family history and/or with low plasma PGRN levels. The
aim of this study was to determine their pathogenicity. We performed functional
studies, analyzing PGRN expression, secretion, and cleavage by elastase. GRN
C105Y affected both secretion and elastase cleavage, likely representing a
pathogenic mutation. GRN A199V did not alter the physiological properties of
PGRN and GRN R298H produced only moderate effects on PGRN secretion, indicating
that their pathogenicity is uncertain. In the absence of strong segregation data
and neuropathological examinations, genetic, biomarker, and functional studies
can be applied to an algorithm to assess the likelihood of pathogenicity for a
mutation. This information can improve our understanding of the complex
mechanisms by which GRN mutations lead to FTLD. Loss-of-function mutations in GRN cause frontotemporal dementia (FTD) with
transactive response DNA-binding protein of 43 kD (TDP-43)-positive inclusions
and neuronal ceroid lipofuscinosis (NCL). There are no disease-modifying
therapies for either FTD or NCL, in part because of a poor understanding of how
mutations in genes such as GRN contribute to disease pathogenesis and
neurodegeneration. By studying mice lacking progranulin (PGRN), the protein
encoded by GRN, we discovered multiple lines of evidence that PGRN deficiency
results in impairment of autophagy, a key cellular degradation pathway.
PGRN-deficient mice are sensitive to Listeria monocytogenes because of deficits
in xenophagy, a specialized form of autophagy that mediates clearance of
intracellular pathogens. Cells lacking PGRN display reduced autophagic flux, and
pathological forms of TDP-43 typically cleared by autophagy accumulate more
rapidly in PGRN-deficient neurons. Our findings implicate autophagy as a novel
therapeutic target for GRN-associated NCL and FTD and highlight the emerging
theme of defective autophagy in the broader FTD/amyotrophic lateral sclerosis
spectrum of neurodegenerative disease. Progranulin, a secreted glycoprotein, is encoded in humans by the single GRN
gene. Progranulin consists of seven and a half, tandemly repeated, non-identical
copies of the 12 cysteine granulin motif. Many cellular processes and diseases
are associated with this unique pleiotropic factor that include, but are not
limited to, embryogenesis, tumorigenesis, inflammation, wound repair,
neurodegeneration and lysosome function. Haploinsufficiency caused by autosomal
domit mutations within the GRN gene leads to frontotemporal lobar
degeneration, a progressive neuronal atrophy that presents in patients as
frontotemporal dementia. Frontotemporal dementia is an early onset form of
dementia, distinct from Alzheimer's disease. The GRN-related form of
frontotemporal lobar dementia is a proteinopathy characterized by the appearance
of neuronal inclusions containing ubiquitinated and fragmented TDP-43 (encoded
by TARDBP). The neurotrophic and neuro-immunomodulatory properties of
progranulin have recently been reported but are still not well understood. Gene
delivery of GRN in experimental models of Alzheimer's- and Parkinson's-like
diseases inhibits phenotype progression. Here we review what is currently known
concerning the molecular function and mechanism of action of progranulin in
normal physiological and pathophysiological conditions in both in vitro and in
vivo models. The potential therapeutic applications of progranulin in treating
neurodegenerative diseases are highlighted. Neurodegenerative diseases such as Alzheimer's disease have proven resistant to
new treatments. The complexity of neurodegenerative disease mechanisms can be
highlighted by accumulating evidence for a role for a growth factor, progranulin
(PGRN). PGRN is a glycoprotein encoded by the GRN/Grn gene with multiple
cellular functions, including neurotrophic, anti-inflammatory and lysosome
regulatory properties. Mutations in the GRN gene can lead to frontotemporal
lobar degeneration (FTLD), a cause of dementia, and neuronal ceroid
lipofuscinosis (NCL), a lysosomal storage disease. Both diseases are associated
with loss of PGRN function resulting, amongst other features, in enhanced
microglial neuroinflammation and lysosomal dysfunction. PGRN has also been
implicated in Alzheimer's disease (AD). Unlike FTLD, increased expression of
PGRN occurs in brains of human AD cases and AD model mice, particularly in
activated microglia. How microglial PGRN might be involved in AD and other
neurodegenerative diseases will be discussed. A unifying feature of PGRN in
diseases might be its modulation of lysosomal function in neurons and microglia.
Many experimental models have focused on consequences of PGRN gene deletion:
however, possible outcomes of increasing PGRN on microglial inflammation and
neurodegeneration will be discussed. We will also suggest directions for future
studies on PGRN and microglia in relation to neurodegenerative diseases. Mutations in the GRN gene coding for progranulin (PGRN) are responsible for many
cases of familial frontotemporal lobar degeneration (FTLD) with TAR DNA-binding
protein 43 (TDP-43)-positive inclusions (FTLD-TDP). GRN mutations create null
alleles resulting in decreased progranulin protein or haploinsufficiency.
FTLD-TDP with GRN mutations is characterized by lentiform neuronal intranuclear
inclusions that are positive for TDP-43 in affected brain regions. In this
study, by stably expressed short hairpin RNA, we established a neuroblastoma
cell line with decreased PGRN level. This cell line reveals TDP-43-positive
intranuclear inclusions. In addition, replacement with purified PGRN protein
restores normal TDP-43 nuclear distribution. This cell model can be valuable for
the study of the role of PGRN in the pathogenesis in FTLD-TDP. Progranulin (PGRN) is a protein encoded by the GRN gene with multiple identified
functions including as a neurotrophic factor, tumorigenic growth factor,
anti-inflammatory cytokine and regulator of lysosomal function. A single
mutation in the human GRN gene resulting in reduced PGRN expression causes types
of frontotemporal lobar degeneration resulting in frontotemporal dementia.
Prosaposin (PSAP) is also a multifunctional neuroprotective secreted protein and
regulator of lysosomal function. Interactions of PGRN and PSAP affect their
functional properties. Their roles in Alzheimer's disease (AD), the leading
cause of dementia, have not been defined. In this report, we examined in detail
the cellular expression of PGRN in middle temporal gyrus samples of a series of
human brain cases (n = 45) staged for increasing plaque pathology.
Immunohistochemistry showed PGRN expression in cortical neurons, microglia,
cerebral vessels and amyloid beta (Aβ) plaques, while PSAP expression was mainly
detected in neurons and Aβ plaques, and to a limited extent in astrocytes. We
showed that there were increased levels of PGRN protein in AD cases and
corresponding increased levels of PSAP. Levels of PGRN and PSAP protein
positively correlated with amyloid beta (Aβ), with PGRN levels correlating with
phosphorylated tau (serine 205) levels in these samples. Although PGRN
colocalized with lysosomal-associated membrane protein-1 in neurons, most PGRN
associated with Aβ plaques did not. Aβ plaques with PGRN and PSAP deposits were
identified in the low plaque non-demented cases suggesting this was an early
event in plaque formation. We did not observe PGRN-positive neurofibrillary
tangles. Co-immunoprecipitation studies of PGRN from brain samples identified
only PSAP associated with PGRN, not sortilin or other known PGRN-binding
proteins, under conditions used. Most PGRN associated with Aβ plaques were
immunoreactive for PSAP showing a high degree of colocalization of these
proteins that did not change between disease groups. As PGRN supplementation has
been considered as a therapeutic approach for AD, the possible involvement of
PGRN and PSAP interactions in AD pathology needs to be further considered. Loss-of-function mutations in the gene encoding for the protein progranulin
(PGRN), GRN, are one of the major genetic abnormalities involved in
frontotemporal lobar degeneration. However, genetic variations, mainly missense,
in GRN have also been linked to other neurodegenerative diseases. We found 12
different pathogenic/likely pathogenic variants in 21 patients identified in a
cohort of Italian patients affected by various neurodegenerative disorders. We
detected the p.Thr272SerfsTer10 as the most frequent, followed by the
c.1179+3A>G variant. We characterized the clinical phenotype of 12 patients from
3 pedigrees carrying the c.1179+3A>G variant, demonstrated the pathogenicity of
this mutation, and detected other rarer variants causing haploinsufficiency
(p.Met1?, c.709-2A>T, p.Gly79AspfsTer39). Finally, by applying bioinformatics,
neuropathological, and biochemical studies, we characterized 6
missense/synonymous variants (p.Asp94His, p.Gly117Asp, p.Ala266Pro, p.Val279Val,
p.Arg298His, p.Ala505Gly), including 4 previously unreported. The designation of
variants is crucial for genetic counseling and the enrollment of patients in
clinical studies. Single nucleotide polymorphisms (SNPs) in TMEM106B encoding the lysosomal type
II transmembrane protein 106B increase the risk for frontotemporal lobar
degeneration (FTLD) of GRN (progranulin gene) mutation carriers. Currently, it
is unclear if progranulin (PGRN) and TMEM106B are synergistically linked and if
a gain or a loss of function of TMEM106B is responsible for the increased
disease risk of patients with GRN haploinsufficiency. We therefore compare
behavioral abnormalities, gene expression patterns, lysosomal activity, and
TDP-43 pathology in single and double knockout animals. Grn-/- /Tmem106b-/- mice
show a strongly reduced life span and massive motor deficits. Gene expression
analysis reveals an upregulation of molecular signature characteristic for
disease-associated microglia and autophagy. Dysregulation of maturation of
lysosomal proteins as well as an accumulation of ubiquitinated proteins and
widespread p62 deposition suggest that proteostasis is impaired. Moreover, while
single Grn-/- knockouts only occasionally show TDP-43 pathology, the double
knockout mice exhibit deposition of phosphorylated TDP-43. Thus, a loss of
function of TMEM106B may enhance the risk for GRN-associated FTLD by reduced
protein turnover in the lysosomal/autophagic system. Numerous kindreds with familial frontotemporal lobar degeneration have been
linked to mutations in microtubule-associated protein tau (MAPT) or progranulin
(GRN) genes. While there are many similarities in the clinical manifestations
and associated neuroimaging findings, there are also distinct differences. In
this review, we compare and contrast the demographic/inheritance
characteristics, histopathology, pathophysiology, clinical aspects, and key
neuroimaging findings between those with MAPT and GRN mutations. It has been more than a decade since heterozygous loss-of-function mutations in
the progranulin gene (GRN) were first identified as an important genetic cause
of frontotemporal lobar degeneration (FTLD). Due to the highly diverse
biological functions of the progranulin (PGRN) protein, encoded by GRN, multiple
possible disease mechanisms have been proposed. Early work focused on the
neurotrophic properties of PGRN and its role in the inflammatory response.
However, since the discovery of homozygous GRN mutations in patients with a
lysosomal storage disorder, investigation into the possible roles of PGRN and
its proteolytic cleavage products granulins, in lysosomal function and
dysfunction, has taken center stage. In this chapter, we summarize the GRN
mutational spectrum and its associated phenotypes followed by an in-depth
discussion on the possible disease mechanisms implicated in FTLD-GRN. We
conclude with key outstanding questions which urgently require answers to ensure
safe and successful therapy development for GRN mutation carriers. The granulin protein (also known as, and hereafter referred to as, progranulin)
is a secreted glycoprotein that contributes to overall brain health.
Heterozygous loss-of-function mutations in the gene encoding the progranulin
protein (Granulin Precursor, GRN) are a common cause of familial frontotemporal
dementia (FTD). Gene therapy approaches that aim to increase progranulin
expression from a single wild-type allele, an area of active investigation for
the potential treatment of GRN-dependent FTD, will benefit from the availability
of a mouse model that expresses a genomic copy of the human GRN gene. Here we
report the development and characterization of a novel mouse model that
expresses the entire human GRN gene in its native genomic context as a single
copy inserted into a defined locus (Hprt) in the mouse genome. We show that
human and mouse progranulin are expressed in a similar tissue-specific pattern,
suggesting that the two genes are regulated by similar mechanisms. Human
progranulin rescues a phenotype characteristic of progranulin-null mice, the
exaggerated and early deposition of the aging pigment lipofuscin in the brain,
indicating that the two proteins are functionally similar. Longitudinal
behavioural and neuropathological analyses revealed no significant differences
between wild-type and human progranulin-overexpressing mice up to 18 months of
age, providing evidence that long-term increase of progranulin levels is well
tolerated in mice. Finally, we demonstrate that human progranulin expression can
be increased in the brain using an antisense oligonucleotide that inhibits a
known GRN-regulating micro-RNA, demonstrating that the transgene is responsive
to potential gene therapy drugs. Human progranulin-expressing mice represent a
novel and valuable tool to expedite the development of progranulin-modulating
therapeutics. |
What is the difference in the roles of Tcf1 and Tcf3 during development? | Τhere are opposing effects of Tcf3 and Tcf1 in the control of Wnt stimulation of embryonic stem cell self-renewal. In contrast to β-catenin-dependent functions described for Tcf1 the known embryonic functions for Tcf3 are consistent with β-catenin-independent repressor activity. Wnt signal stimulation reduces the level of Tcf3, and increases those of Tcf1 (also known as Tcf7) and Lef1, positive mediators of Wnt signaling. | The co-occupancy of Tcf3 with Oct4, Sox2 and Nanog on embryonic stem cell (ESC)
chromatin indicated that Tcf3 has been suggested to play an integral role in a
poorly understood mechanism underlying Wnt-dependent stimulation of mouse ESC
self-renewal of mouse ESCs. Although the conventional view of Tcf proteins as
the β-catenin-binding effectors of Wnt signalling suggested Tcf3-β-catenin
activation of target genes would stimulate self-renewal, here we show that an
antagonistic relationship between Wnt3a and Tcf3 on gene expression regulates
ESC self-renewal. Genetic ablation of Tcf3 replaced the requirement for
exogenous Wnt3a or GSK3 inhibition for ESC self-renewal, demonstrating that
inhibition of Tcf3 repressor is the necessary downstream effect of Wnt
signalling. Interestingly, both Tcf3-β-catenin and Tcf1-β-catenin interactions
contributed to Wnt stimulation of self-renewal and gene expression, and the
combination of Tcf3 and Tcf1 recruited Wnt-stabilized β-catenin to Oct4 binding
sites on ESC chromatin. This work elucidates the molecular link between the
effects of Wnt and the regulation of the Oct4/Sox2/Nanog network. The canonical Wnt/β-catenin signaling pathway classically functions through the
activation of target genes by Tcf/Lef-β-catenin complexes. In contrast to
β-catenin-dependent functions described for Tcf1, Tcf4 and Lef1, the known
embryonic functions for Tcf3 in mice, frogs and fish are consistent with
β-catenin-independent repressor activity. In this study, we genetically define
Tcf3-β-catenin functions in mice by generating a Tcf3ΔN knock-in mutation that
specifically ablates Tcf3-β-catenin. Mouse embryos homozygous for the knock-in
mutation (Tcf3(ΔN/ΔN)) progress through gastrulation without apparent defects,
thus genetically proving that Tcf3 function during gastrulation is independent
of β-catenin interaction. Tcf3(ΔN/ΔN) mice were not viable, and several
post-gastrulation defects revealed the first in vivo functions of Tcf3-β-catenin
interaction affecting limb development, vascular integrity, neural tube closure
and eyelid closure. Interestingly, the etiology of defects indicated an indirect
role for Tcf3-β-catenin in the activation of target genes. Tcf3 directly
represses transcription of Lef1, which is stimulated by Wnt/β-catenin activity.
These genetic data indicate that Tcf3-β-catenin is not necessary to activate
target genes directly. Instead, our findings support the existence of a
regulatory circuit whereby Wnt/β-catenin counteracts Tcf3 repression of Lef1,
which subsequently activates target gene expression via Lef1-β-catenin
complexes. We propose that the Tcf/Lef circuit model provides a mechanism
downstream of β-catenin stability for controlling the strength of Wnt signaling
activity during embryonic development. During mouse neocortical development, the Wnt-β-catenin signaling pathway plays
essential roles in various phenomena including neuronal differentiation and
proliferation of neural precursor cells (NPCs). Production of the appropriate
number of neurons without depletion of the NPC population requires precise
regulation of the balance between differentiation and maintece of NPCs.
However, the mechanism that suppresses Wnt signaling to prevent premature
neuronal differentiation of NPCs is poorly understood. We now show that the HMG
box transcription factor Tcf3 (also known as Tcf7l1) contributes to this
mechanism. Tcf3 is highly expressed in undifferentiated NPCs in the mouse
neocortex, and its expression is reduced in intermediate neuronal progenitors
(INPs) committed to the neuronal fate. We found Tcf3 to be a repressor of Wnt
signaling in neocortical NPCs in a reporter gene assay. Tcf3 bound to the
promoter of the proneural bHLH gene Neurogenin1 (Neurog1) and repressed its
expression. Consistent with this, Tcf3 repressed neuronal differentiation and
increased the self-renewal activity of NPCs. We also found that Wnt signal
stimulation reduces the level of Tcf3, and increases those of Tcf1 (also known
as Tcf7) and Lef1, positive mediators of Wnt signaling, in NPCs. Together, these
results suggest that Tcf3 antagonizes Wnt signaling in NPCs, thereby maintaining
their undifferentiated state in the neocortex and that Wnt signaling promotes
the transition from Tcf3-mediated repression to Tcf1/Lef1-mediated enhancement
of Wnt signaling, constituting a positive feedback loop that facilitates
neuronal differentiation. |
Why mix γ-cyclodextrin with grapefruit juice? | Grapefruit (Citrus paradisi) juice enhances the oral bioavailability of drugs that are metabolized by intestinal cytochrome P450 3A4 (CYP3A4). Patients are advised to avoid drinking grapefruit juice to prevent this drug-grapefruit juice interaction. The inhibition of CYP3A by grapefruit juice was significantly attenuated by processing particularly with γCD. The inhibition of CYP3A by grapefruit juice was significantly attenuated by processing particularly with γCD. Similar attenuation effects by γCD were observed in the cases of BG and DHBG. Furthermore, BG and DHBG were suggested to be strongly encapsulated in the cavity of γCD.The encapsulation of BG and DHBG by γCD and the resulting attenuation of the inhibition of CYP3A activity by grapefruit juice may be applicable to juice processing for preventing drug-grapefruit juice interactions. | |
What is disrupted by ALS- and FTD-associated missense mutations in TBK1? | ALS- and FTD-associated missense mutations in TBK1 differentially disrupt mitophagy. | TANK-binding kinase 1 (TBK1) is a multifunctional kinase with an essential role
in mitophagy, the selective clearance of damaged mitochondria. More than 90
distinct mutations in TBK1 are linked to amyotrophic lateral sclerosis (ALS) and
fronto-temporal dementia, including missense mutations that disrupt the
abilities of TBK1 to dimerize, associate with the mitophagy receptor optineurin
(OPTN), autoactivate, or catalyze phosphorylation. We investigated how
ALS-associated mutations in TBK1 affect Parkin-dependent mitophagy using imaging
to dissect the molecular mechanisms involved in clearing damaged mitochondria.
Some mutations cause severe dysregulation of the pathway, while others induce
limited disruption. Mutations that abolish either TBK1 dimerization or kinase
activity were insufficient to fully inhibit mitophagy, while mutations that
reduced both dimerization and kinase activity were more disruptive. Ultimately,
both TBK1 recruitment and OPTN phosphorylation at S177 are necessary for
engulfment of damaged mitochondra by autophagosomal membranes. Surprisingly, we
find that ULK1 activity contributes to the phosphorylation of OPTN in the
presence of either wild-type or kinase-inactive TBK1. In primary neurons, TBK1
mutants induce mitochondrial stress under basal conditions; network stress is
exacerbated with further mitochondrial insult. Our study further refines the
model for TBK1 function in mitophagy, demonstrating that some ALS-linked
mutations likely contribute to disease pathogenesis by inducing mitochondrial
stress or inhibiting mitophagic flux. Other TBK1 mutations exhibited much less
impact on mitophagy in our assays, suggesting that cell-type-specific effects,
cumulative damage, or alternative TBK1-dependent pathways such as innate
immunity and inflammation also factor into the development of ALS in affected
individuals. |
What is Morel–Lavallée lesion? | Morel-Lavallée lesion is a closed degloving soft-tissue injury that results in the accumulation of a hemolymphatic fluid between the skin/superficial fascia and the deep fascia. | BACKGROUND: The Morel-Lavallee lesion is a closed degloving injury most commonly
described in the region of the hip joint after blunt trauma. It also occurs in
the knee as a result of shearing trauma during football and is a distinct lesion
from prepatellar bursitis and quadriceps contusion.
PURPOSE: To review the authors' experience with Morel-Lavallee lesion of the
knee in the elite contact athlete to construct a diagnostic and treatment
algorithm.
STUDY DESIGN: Case series; Level of evidence, 4.
METHODS: Twenty-seven knees in 24 players were identified from 1 National
Football League team's annual injury database as having sustained a
Morel-Lavallee lesion between 1993 and 2006. Their charts were retrospectively
reviewed.
RESULTS: The most common mechanism of injury was a shearing blow on the playing
surface (81%). The most common motion deficit was active flexion (41%). The mean
time for resolution of the fluid collection and achievement of full active
flexion was 16.3 days. The mean number of practices missed was 1.5. The mean
number of games missed was 0.1. Fourteen knees (52%) were treated successfully
with compression wrap, cryotherapy, and motion exercises. Thirteen knees (48%)
were treated with at least 1 aspiration, and 6 knees (22%) were treated with
multiple aspirations for recurrent serosanguineous fluid collections. In 3 cases
(11%), the Morel-Lavallee lesion was successfully treated with doxycycline
sclerodesis after 3 aspirations failed to resolve the recurrent fluid
collections; return to play was immediate thereafter in each case.
CONCLUSION: In football, Morel-Lavallee lesion of the knee usually occurs from a
shearing blow from the playing field. Diagnosis is confirmed when examination
reveals a large suprapatellar area of palpable fluctuance. Elite athletes are
typically able to return to practice and game play long before complete
resolution of the lesion. Recurrent fluid collections can occur, necessitating
aspiration in approximately half the cases for successful treatment.
Recalcitrant fluid collections can be safely and expeditiously treated with
doxycycline sclerodesis. A Morel-Lavallée lesion is a relatively rare condition involving a closed,
degloving injury to the pelvis, resulting in a blood-filled cystic cavity
created by separation of the subcutaneous tissue from the underlying fascia.
This injury typically occurs following high-speed trauma. We describe a case
that occurred in a professional American football player who was treated with
percutaneous decompression and evacuation of the hematoma. The player returned
to playing football at the professional level 22 days after the injury without
residual deformity or disability. A Morel-Lavallée lesion (MLL) is a posttraumatic soft-tissue injury
characterized by an accumulation of blood, lymph, and other physiologic
breakdown products between subcutaneous tissue and underlying fascia. It was
first described as occurring over the proximal lateral thigh, but it has since
been documented at various anatomic locations. Diagnosis is typically made by
careful physical examination and a radiographic analysis, most commonly with
magnetic resoce imaging (MRI). Recently, musculoskeletal ultrasound (US) has
been recognized as a useful adjunct to and potential replacement for MRI in the
diagnosis and monitoring of an MLL. We present a case report of a patient with
an MLL of the knee. We obtained magenetic resoce (MRI) and US images at the
time of diagnosis, and follow-up US images during convalescence. By doing so, we
were able to identify several key sonographic findings of an MLL at this
location and compare them with MRI. Although there have been several published
reports to date that describe the use of musculoskeletal US in the diagnosis of
MLL, this is the first of which we are aware that does so at the knee. BACKGROUND: The Morel-Lavallée lesion is a post-traumatic collection of fluid
arising after a 'closed degloving injury' has caused the separation of the skin
and subcutis from the underlying muscular fascia. It usually occurs in the
trochanteric region or proximal thigh.
CASE DESCRIPTION: A 36-year-old obese man was referred to the emergency
department by his general practitioner for fever and pain in the right lower
abdominal quadrant. Blood testing revealed elevated infection parameters. As
appendicitis was suspected, a CT scan of the abdomen was performed. This
revealed a Morel-Lavallée lesion, which he had sustained 9 months earlier when
he had been hit by a car while riding his bicycle. A rapid recovery ensued after
ultrasound-guided percutaneous drainage and treatment with antibiotics.
CONCLUSION: A Morel-Lavallée lesion, which could manifest even months later,
should be considered after any traumatic injury. Ultrasound, CT and MRI are
useful tools for proper diagnosis. There is no consensus about treatment in
either the acute or the chronic phase to date. BACKGROUND CONTEXT: The Morel-Lavallée lesion occurs from a compression and
shear force that usually separates the skin and subcutaneous tissue from the
underlying muscular fascia. A dead space is created that becomes filled with
blood, liquefied fat, and lymphatic fluid from the shearing of vasculature and
lymphatics. If not treated appropriately, these lesions can become infected,
cause tissue necrosis, or form chronic seromas.
PURPOSE: To review appropriate identification and treatment of Morel-Lavallée
lesions in spinopelvic dissociation patients.
STUDY DESIGN: Uncontrolled case series.
METHODS: Retrospective review of medical records. No funding was received in
support of this study. The authors report no conflicts of interest.
RESULTS: We present four cases of patients with traumatic spinopelvic
dissociation. All had concomitant lumbosacral Morel-Lavallée lesions. All four
trauma patients suffered traumatic spinopelvic dissociation with concomitant
lumbosacral Morel-Lavallée lesions. Appropriate treatment included irrigation
and debridement, drainage, antibiotics, and vacuum-assisted wound closure.
CONCLUSIONS: Our series reflects an association of Morel-Lavallée lesion in
spinopelvic dissociation trauma patients. Possibly, the rotatory injury that
occurs at the spinopelvic junction creates a shear force to form the
Morel-Lavallée lesion. When presented with a spinopelvic dissociation patient,
one should be prepared to treat a Morel-Lavallée lesion. Morel-Lavallée lesions are post-traumatic, closed degloving injuries occurring
deep to subcutaneous plane due to disruption of capillaries resulting in an
effusion containing hemolymph and necrotic fat. Magnetic resoce imaging (MRI)
is the modality of choice in the evaluation of Morel-Lavallée lesion. Early
diagnosis and management is essential as any delay in diagnosis or missed lesion
will lead to the effusion becoming infected or leading to extensive skin
necrosis. Morel-lavallee lesion (MLL) represents post traumatic subcutaneous cyst
generally overlying bony prominences like greater trochanter, lower back, knee
and scapula. A 51-year-old man presented with a swelling in left thigh since six
years which was insidious in onset, gradually progressive in size and not
associated with pain, fever or discharge. There was no history of trauma or any
associated constitutional symptoms. Since there was no history of trauma
recalled by the patient the clinical dilemma was between soft tissue sarcoma and
cold abscess. We report a case of slow growing painless mass lesion of thigh,
diagnosed on Magnetic Resoce Imaging (MRI) as morel lavallee lesion and
describe its salient imaging features with treatment options. Morel-Lavallée Lesion (MLL) is a posttraumatic, closed degloving injury where
the skin and superficial fascia get separated from deep fascia (fascialata) in
the trochanteric region and upper thigh, hence creating a potential space.
Similar lesions at other locations (e.g., abdominal wall and lumbar regions)
have been described as Morel-Lavallée effusion, hematoma, or extravasation.
Injury to an area with rich vascular and lymphatic supply leads to filling of
this space with blood, lymph, fat, and necrotic debris. MLL usually presents as
painful fluctuant swelling in the anterolateral portion o fthe upper thigh. Many
of these maybe missed at initial evaluation and present weeks to months after
the initial trauma. The Morel-Lavallée lesion is a closed soft-tissue degloving injury commonly
associated with high-energy trauma. The thigh, hip, and pelvic region are the
most commonly affected locations. Timely identification and management of a
Morel-Lavallée lesion is crucial because distracting injuries in the
polytraumatized patient can result in a missed or delayed diagnosis. Bacterial
colonization of these closed soft-tissue injuries has resulted in their
association with high rates of perioperative infection. Recently, MRI has been
used to characterize and classify these lesions. Definitive management is
dictated by the size, location, and age of the injury and ranges from
percutaneous drainage to open débridement and irrigation. Chronic lesions may
lead to the development of pseudocysts and contour deformities of the extremity. INTRODUCTION: The Morel-Lavallée lesion is an infrequently described,
post-traumatic closed de-gloving wound that results from separation of the skin
and subcutaneous tissues from the underlying deep fascia as a result of shearing
forces that tear perforating vessels and lymphatics. This condition is rare in
children and to our knowledge it represents the youngest case of Morel-Lavallée
lesion yet reported.
PRESENTATION OF CASE: We report on a twelve-month-old girl who presented after a
motor vehicle accident with a tender fluctuant mass of the back and buttocks.
Computed tomography revealed a large but discrete fluid collection between the
subcutaneous fat and the deep fascial planes, extending from the posterior
thoracic paraspinal soft tissues to the right gluteal region. A diagnosis of
Morel-Lavallée lesion was made. This patient was managed with serial
ultrasound-guided percutaneous drainage and compression bandages. The patient
did well and was subsequently discharged. There was no recurrence of the lesion
on follow-up.
DISCUSSION: The Morel-Lavallée lesion is a rare consequence of abrupt high
impact trauma. There is no accepted management approach and a variety of
conservative as well as surgical options exist. Goals of management include
drainage, debridement and meticulous dead space management to prevent
recurrence.
CONCLUSION: The Morel-Lavallée lesion is a rare finding in children involved in
high impact trauma and prompt intervention is crucial to prevent complications.
Image-guided drainage is a rational management approach with excellent outcomes. The Morel-Lavallée lesion (MLL) is a closed degloving injury caused by traumatic
separation of the subcutaneous tissue from the underlying fascia, without a
break in the overlying skin. We present two cases that demonstrate a previously
unrecognised association of the MLL with thoracolumbar spine fractures. The
lesion is frequently missed, or its significance is overlooked, on initial
evaluation. Awareness of this injury should allow tailored strategies to
decrease the high risk of wound complications. Morel-Lavallée lesion (MLL) is a degloving injury in soft tissues caused by
shear force accompanying trauma. Even if it is a small lacrimal wound at the
initial visit, there is a range of skin necrosis which is not suitable for it.
As a cause of the injury, a shearing force was applied over a wide range, and
penetrating blood vessel damage to the skin occurred, resulting in skin
necrosis. Attention is required. Postoperative seroma is a common complication of many surgical procedures in
which anatomical dead space has been created. A particular case of lesion in
which seroma occurs is the Morel-Lavallée lesion (MLL), which is an uncommon
closed soft-tissue degloving injury that develops after high-energy trauma or
crush injury where shearing forces separate the subcutaneous tissue from the
underlying fascia. The diagnostic evaluation begins with an adequate history and
physical examination, followed by instrumental research with ultrasonography,
computed tomography, and magnetic resoce imaging. Postoperative seromas and
MLLs share a similar pathology and natural evolution as both injuries, once
chronic, develop a pseudobursa; thus, the authors think that the same treatment
algorithm may be suitable for both the lesions. Several strategies for the
treatment of post-surgical and post-traumatic seromas have been described in the
literature, ranging from conservative measures for acute and small injuries to
surgical management and sclerotherapy for chronic and large ones. Despite some
seromas resolving with conventional management, lesion recurrence is a matter of
concern. The authors present their experience in the treatment of both
post-surgical and post-traumatic chronic seromas not responsive to conservative
treatments by surgical drainage of the seroma, capsulectomy, and application of
vacuum-assisted closure therapy to allow granulation tissue formation, dead
spaces obliteration, and wound healing. Primary wound closure with closed
suction drain placement and an elastic compression bandaging are finally
performed. From 2014 to 2019, a total of 15 patients (9 females and 6 males)
were treated for recurrent chronic seromas with the proposed surgical approach.
Five cases were MLLs, while 10 cases were postoperative seromas. The patients
were between 33 and 79 years old, and they were followed up at 4 weeks and 3 and
6 months after surgery. All 15 patients with chronic seromas not responsive to
conservative treatment showed a complete resolution of the lesions with the
proposed treatment approach with no evidence of lesion recurrence, proving its
effectiveness. INTRODUCTION: Soft tissue injuries are a common presenting complaint seen in the
emergency department following trauma. However, internal degloving injuries are
not commonly seen by the emergency provider.
CASE REPORT: A 57-year-old male presented with right lower extremity pain,
bruising, and swelling after a low-speed bicycle accident five days prior.
Physical examination revealed an edematous and ecchymotic right lower extremity
extending from the mid-thigh distally. Computed tomography of the thigh
demonstrated a hyperdense foci within the fluid collection suggesting internal
hemorrhage and internal de-gloving suggestive of a Morel-Lavallée lesion.
DISCUSSION: The Morel-Lavallée lesion is a post-traumatic soft tissue injury
that occurs as a result of shearing forces that create a potential space for the
collection of blood, lymph, and fat. First described in 1853 by French physician
Maurice Morel-Lavallée, this internal degloving injury can serve as a nidus of
infection if not treated appropriately. Magnetic resoce imaging has become
the diagnostic modality of choice due to its high resolution of soft tissue
injuries. Treatment has been focused on either conservative management or
surgical debridement after consultation with a surgeon.
CONCLUSION: The emergency physician should consider Morel-Lavallée lesions in
patients with a traumatic hematoma formation to avoid complications that come
from delayed diagnosis. INTRODUCTION: Morel-Lavallée lesion (MLL) is a posttraumatic closed degloving
soft tissue injury, in which the subcutaneous tissues are separated from the
underlying fascia. Surgical treatment is recommended if conservative management
fails. The conventional surgical treatment for the lesion is surgical drainage
and debridement.
PRESENTATION OF CASE: A 51-year-old male patient presented with swelling of the
right thigh incurred during a traffic accident. The lesion was diagnosed with
MLL. The MLL was successfully treated with a minimally invasive arthroscopic
treatment after failure of conservative treatment. The arthroscopic treatment
was chosen because of the patient's comorbidity that posed a risk of surgical
wound complications. In addition, negative pressure wound therapy (NPWT) was
performed postoperatively to ensure healing and to prevent recurrence of the
lesion. The patient was successfully treated and the healing of the lesion was
also confirmed with MRI.
DISCUSSION: In a patient with a risk of wound complications due to a
comorbidity, this minimally invasive arthroscopic treatment is useful. In
addition, NPWT was used to ensure healing and to prevent recurrence. Although
the use of NPWT combined with endoscopic treatment has not been reported,
additional NPWT reported in this case may be helpful to ensure healing.
CONCLUSION: In case of MLL with a risk of surgical complications, the
arthroscopic treatment is a reasonable method and achieves the goal of an open
surgical debridement without increased morbidity. The Morel-Lavallée lesion (MLL) is a posttraumatic close degloving injury, which
is often underdiagnosed at first. Patients with MLLs usually present with tender
and enlarging soft tissue swelling with fluctuation, decreased skin sensation,
ecchymosis, or even skin necrosis hours to days after the inciting injury. The
lesion can lead to intractable morbidity if it remains untreated. There is no
consensus regarding the treatment for MLL at present. Here, we report an MLL in
the pretibial region of a 43-year-old woman who experienced a low-energy
contusion in a motorbike accident. The pretibial lesion was diagnosed using
sonography and fine-needle aspiration. We successfully treated the patient by
performing percutaneous debridement via a small incision and injections of
fibrin after conservative treatment failed. The method we herein propose
achieved the goal of open surgical debridement, providing faster recovery and a
high degree of patient comfort. We reviewed the available pertinent literature
and propose our own treatment protocol with the aim to establish common
therapies ofMLL. INTRODUCTION AND IMPORTANCE: A Morel-Lavallee lesion is a closed degloving
injury due to traumatic separation of the hypodermis from underlying fascia.
Accumulation of hemolymphatic fluid that occurs is a potential habitat for
bacteria. Management options include percutaneous aspiration, open debridement,
or a non-surgical approach, each with recurrence risk. In the event of
recurrence, sclerotherapy is used. In this case report, after reviewing povidone
iodine's efficacy in treating seromas, we used it as a sclerosant for recurrent
Morel-Lavallee lesion as the more established options were unavailable in our
setting.
CASE PRESENTATION: A 49-year-old with no known comorbid presented following a
motor traffic accident, with left lateral thigh swelling. He was stable
systematically, with a tense, tender left lateral thigh swelling and intact
neurovascular assessment distally. X-ray and computed tomography ruled out
skeletal and vascular injuries. Magnetic resoce imaging revealed a 580 ml
type 1 Morell-Lavallee lesion. Open surgical debridement was done to drain and
debride the lesion. He developed two recurrences that necessitated percutaneous
aspiration. Doxycycline and talc sclerosants were considered; however, due to
their unavailability, povidone iodine was used. It is now five months
post-intervention without increased pain, recurrence, or wound complications.
CLINICAL DISCUSSION: Recurrence is hypothesized to be due to the persistence of
fluid loculations, unobliterated dead space, and pseudocyst formation.
Sclerotherapy stimulates inflammation that results in fibrosis of the cavity
walls causing its obliteration. Doxycycline, the most studied sclerosant in
Morel-Lavallée lesion has an efficacy of 95.7%.
CONCLUSION: The current report is the first successful use of povidone iodine
for sclerotherapy of recurring Morel-Lavallée lesions. Based on povidone iodine
experiences as a sclerosant, it is associated with increased analgesic
requirements. We cautiously propose its use as an alternative in settings where
talc powder and doxycycline powder are unavailable. Morel-Lavallée lesion is a post-traumatic degloving cyst, usually filled with
blood, lymph or necrotic tissue, which mostly develops in the area around
greater trochanter. Early diagnosis and prompt treatment is essential to prevent
further complications, such as compression of surrounding structures. X-rays
have limited use and magnetic resoce imaging (MRI) is the modality of choice
in diagnosing the lesion. We report a case of a 35-year female presenting with
left thigh pain after a fall from motorcycle almost 21/2 years ago. Ultrasound
and MRI confirmed the presence of Morel-Lavallée lesion involving the left
pelvis and upper thigh. Given the chronicity of lesion and extensive tissue
involvement, the patient underwent surgical excision of the lesion with
favourable long-term outcomes. In this case report and literature review, we
discuss the pathophysiology, clinical presentation, radiological findings and
management options for Morel-Lavallée lesion. Key Words: Morel-Lavallée lesion,
Post-traumatic cyst, Degloving Injury, Tangential cyst. The Morel-Lavallée lesion is a closed internal soft-tissue degloving injury.
About 15.7% of Morel-Lavallée lesions occur in the knee region. Morel-Lavallée
lesions are considered chronic when the lesion contains a capsule. The capsule
prevents resorption of the fluid content, and the lesion will recur when using
conservative treatment alone. Surgical debridement with resection of the capsule
is a more definitive treatment option, but it may induce wound complications. In
this Technical Note, the technical details of endoscopic resection of chronic
Morel-Lavallée lesion of the knee are discussed. This minimally invasive
technique has the advantage of better cosmetic results and fewer wound
complications. |
What is known about the protein patatin? | Patatin, the major protein found in potatoes, was purified and shows several isoforms. The essential amino acid content of patatin was ashighas 76%, indicating that it is a valuable protein source. Patatin was an O-linked glycoprotein that contained fucose monosaccharides, as well as mannose, rhamnose, glucose, galactose, xylose, and arabinose. Patatin had a fucosylated glycan structural feature, which strongly bound AAL (Aleuria aurantia Leukoagglutinin), a known fucose binding lectin. Moreover, thelipid metabolism regulatory effects of patatin on the fat catabolism, fat absorption, and inhibition of lipase activity were measured after high-fat feeding of zebrafish larvae. Results revealed that 37.0 μg/mL patatin promoted 23% lipid decomposition metabolism. Meanwhile patatin could inhibite lipase activity and fat absorption, whose effects accounted for half that of a positive control drug. Our findings suggest that patatin, a fucosylated glycoprotein, could potentially be used as a naturalactiveconstituent with anti-obesity effects. | Potato patatin is considered a valuable plant protein by the food industry for
its exceptional functional properties and nutritional value. Nonetheless, it has
not been widely used due to its low abundance in potatoes and high cost. Pichia
pastoris was utilized for expression of patatin to overcome agricultural
limitations. Biochemical and biophysical characterization of Patatin-B2 (rPatB2)
and Patatin-17 (rPat17) is described. rPatB2 and rPat17 had higher zeta
potential and superior solubility at various pH conditions in comparison with
commercial patatin, whereas particle size distribution was similar. Inflection
temperatures were higher than potato isolated patatins. Antioxidant capacity of
rPatB2 and rPat17 was similar to that of commercial patatin and the specific
enzymatic activity of rPatB2 was 5-fold higher than rPat17 and patatins isolated
from potato. Results indicate yeast-derived patatin properties are comparable to
patatins from potatoes, suggesting their potential use in various plant-based
products such as meat and dairy analogues. |
What is the mode of action of primaquine? | Primaquine (PQ) not only eliminates P. falciparum gametocytes but also kills liver dormant forms of P. vivax and P. ovale. | Four amphipathic drugs, primaquine, propranolol, chlorpromazine and tetracaine,
were used to cause endocytosis in glucose-depleted red cells, and the relative
reduction of membrane surfaces was measured by the toluidine blue (TB) method.
The TB measurements correlated well with the observed electron microscopic
alterations. In vitro blood storage studies indicated loss of cell membrane
during storage correlated with decreasing uptake of TB by the red cells.
Regeneration of cellular ATP with adenosine did not always restore TB uptake by
the cells. Loss of red blood cell membrane either by exocytosis or endocytosis
may occur during normal in vivo or in vitro ageing, and may be increased in
pathological states or by the action of drugs. It has been shown elsewhere that the epidermal growth factor (EGF) in A431 cells
can recycle in receptor-bound state (Teslenko et al., 1987; Sorkin et al., 1989,
1991). Present study deals with the action of primaquine, a lysosomotropic
agent, on EGF-receptor complexes (EGF-RC). By the method of indirect
immunofluorescence with anti-EGF-R monoclonal antibody it is found that
following a 1 h incubation of cells at 37 degrees C in the presence of EGF a
bright staining of endosomes appears in the intranuclear region, while after
incubation of the cells at 4 degrees only margins of cells are stained. Such a
pattern of fluorescence is peculiar of endocytosis in A431 cells. When the cells
were incubated in the presence of a 0.3 mM primaquine for 1 h, the
immunostaining is changed: bright compact spot in the para-Golgi region
appeared. The effect of primaquine is reversible. When the cells after
preincubation with EGF were incubated in the absence of EGF for 3 h at 37
degrees C, the staining of cell margins could be observed again, demonstrating
the recycling of EGF-RC. Under similar conditions of cell incubation, but in the
presence of primaquine, the staining of the para-Golgi region was not changed.
In the experiments with 125I-EGF it was shown that intracellular accumulations
of 125I-EGF were maintained when the cells were incubated in the presence of 0.3
mM primaquine. It is concluded that primaquine inhibits the recycling of EGF-R
in A431 cells. The lysosomotropic amine primaquine has previously been shown to inhibit both
secretory and recycling processes of cells in culture. We have used a cell-free
assay that reconstitutes glycoprotein transport through the Golgi apparatus to
investigate the mechanism of action of primaquine. In this assay, primaquine
inhibits protein transport at a half-maximal concentration of 50 microM, similar
to the concentration previously reported to disrupt protein secretion in
cultured cells. Kinetic analysis of primaquine inhibition indicates that its
point of action is at an early step in the vesicular transport mechanism.
Primaquine does not inhibit the fusion of vesicles already attached to their
target membranes. Primaquine irreversibly inactivates the membranes that form
transport vesicles (donor), but not the membranes that are the destination of
those vesicles (acceptor). Morphological data indicate that primaquine inhibits
the budding of vesicles from the donor membranes. Once formed, the vesicles are
refractile to primaquine action, and their attachment to and fusion with
acceptor membranes proceeds unimpeded. In addition to illuminating the mechanism
of action of primaquine, this study suggests that the selective action of this
agent will make it a useful tool in the study of the formation of transport
vesicles. The growth of a strain of Bacillus megaterium was prevented by a minimal
inhibitory concentration of primaquine of 52 mug/ml or 2 x 10(-4)m. When
exponentially growing cultures received the drug at 6 x 10(-4)m, the rate of
growth was drastically reduced and no further growth occurred after 15 min of
exposure. At this concentration, primaquine was bactericidal, causing a 50%
reduction in the viable population after one doubling time of 45 min. Supplying
primaquine to cultures 30 min after adding radioactive-labeled phenylalanine,
thymidine, uracil, or diaminopimelic acid produced an immediate and complete
inhibition of protein biosynthesis but no inhibition of deoxyribonucleic acid
biosynthesis for at least 15 min, and caused the formation of ribonucleic acid
and cell wall polymer to proceed linearly at rates similar to those established
prior to the addition of drug. This pattern of inhibition of macromolecular
biosyntheses suggests that the major in vivo action of primaquine in B.
megaterium is to block protein synthesis. The cytoadherence of four Plasmodium falciparum malaria isolates (FCR-3, RSA-14,
15 and 17) to monocytes was used as a measure of the expression of monocyte
receptors after the monocytes had been exposed to seven antimalarial drugs.
Quinine, chloroquine, primaquine, pyrimethamine, artemesinin, mefloquine and
proguanil all down-regulated the expression of monocyte receptors by 40% or
greater at the therapeutic concentrations of each drug. Each malaria isolate had
a unique adherence profile for drug induced changes in monocytes. Each drug
appeared to alter the expression of more than one monocyte receptor. The most
effective drugs were quinine, pyrimethamine and palludrin and the least
effective were artemether and mefloquine. The results suggest a previously
undetected immunomodulatory action of antimalarial drugs. BACKGROUND: The challenge in anti-malarial chemotherapy is based on the
emergence of resistance to drugs and the search for medicines against all stages
of the life cycle of Plasmodium spp. as a therapeutic target. Nowadays, many
molecules with anti-malarial activity are reported. However, few studies about
the cellular and molecular mechanisms to understand their mode of action have
been explored. Recently, new primaquine-based hybrids as new molecules with
potential multi-acting anti-malarial activity were reported and two hybrids of
primaquine linked to quinoxaline 1,4-di-N-oxide (PQ-QdNO) were identified as the
most active against erythrocytic, exoerythrocytic and sporogonic stages.
METHODS: To further understand the anti-malarial mode of action (MA) of these
hybrids, hepg2-CD81 were infected with Plasmodium yoelii 17XNL and treated with
PQ-QdNO hybrids during 48 h. After were evaluated the production of ROS, the
mitochondrial depolarization, the total glutathione content, the DNA damage and
proteins related to oxidative stress and death cell.
RESULTS: In a preliminary analysis as tissue schizonticidals, these hybrids
showed a mode of action dependent on peroxides production, but independent of
the activation of transcription factor p53, mitochondrial depolarization and
arrest cell cycle.
CONCLUSIONS: Primaquine-quinoxaline 1,4-di-N-oxide hybrids exert their
antiplasmodial activity in the exoerythrocytic phase by generating high levels
of oxidative stress which promotes the increase of total glutathione levels,
through oxidation stress sensor protein DJ-1. In addition, the role of HIF1a in
the mode of action of quinoxaline 1,4-di-N-oxide is independent of biological
activity. BACKGROUND: The effect of primaquine in preventing Plasmodium vivax relapses
from dormant stages is well established. For Plasmodium ovale, the relapse
characteristics and the use of primaquine is not as well studied. We set to
evaluate the relapsing properties of these 2 species, in relation to primaquine
use among imported malaria cases in a nonendemic setting.
METHODS: We performed a nationwide retrospective study of malaria diagnosed in
Sweden 1995-2019, by reviewing medical records of 3254 cases. All episodes of P.
vivax (n = 972) and P. ovale (n = 251) were selected for analysis.
RESULTS: First time relapses were reported in 80/857 (9.3%) P. vivax and 9/220
(4.1%) P. ovale episodes, respectively (P < .01). Without primaquine, the risk
for relapse was higher in P. vivax, 20/60 (33.3%), compared to 3/30 (10.0%) in
P. ovale (hazard ratio [HR] 3.5, 95% confidence interval [CI] 1.0-12.0). In P.
vivax, patients prescribed primaquine had a reduced risk of relapse compared to
episodes without relapse preventing treatment, 7.1% vs 33.3% (HR 0.2, 95% CI
.1-.3). In P. ovale, the effect of primaquine on the risk of relapse did not
reach statistical significance, with relapses seen in 2.8% of the episodes
compared to 10.0% in patients not receiving relapse preventing treatment (HR
0.3, 95% CI .1-1.1).
CONCLUSIONS: The risk of relapse was considerably lower in P. ovale than in P.
vivax infections indicating different relapsing features between the two
species. Primaquine was effective in preventing P. vivax relapse. In P. ovale,
relapse episodes were few, and the supportive evidence for primaquine remains
limited. Primaquine (PQ) not only eliminates P. falciparum gametocytes but also kills
liver dormant forms of P. vivax and P. ovale. Owing to these unique therapeutic
properties, it is an essential drug. Although PQ has been used for over 70
years, its toxicological database has gaps such as the absence of studies on its
reproductive and developmental toxicity and kinetics in pregcy. This study
investigated the transplacental transfer of PQ and the effects of intrauterine
exposure on the postnatal growth, survival, and neurobehavioral development of
the offspring. PQ kinetics and transplacental transfer were investigated in rats
treated orally (40 mg.kg·bw-1) on gestation day (GD) 21. PQ was analyzed by
high-performance liquid chromatography with diode array ultraviolet detection.
To evaluate effects of intrauterine exposure on postnatal development, dams were
treated orally with PQ (20 mg.kg·bw-1·d-1) or water (controls) on GD 0-21.
Postnatal survival, body weight gain, somatic maturation, and reflex acquisition
were evaluated. The open field test (OF) was conducted on PND 25. PQ
concentration in the fetal plasma was nearly half that in maternal plasma.
Except for increase in pregcy loss, no effects of PQ were noted at term
pregcy and first days of life. Prenatal PQ did not affect postnatal weight
gain nor did it impair somatic and neurologic development of the offspring. Pups
born to PQ-treated dams showed reduced exploration and enhanced emotionality in
the OF. PQ given in pregcy, at doses greater than those recommended for
malaria therapy, may affect pup postnatal survival and emotional behavior. Malaria is the most common parasitic disease around the world, especially in
tropical and sub-tropical regions. This parasitic disease can have a rapid and
severe evolution. It is transmitted by female anopheline mosquitoes. There is no
reliable vaccine or diagnostic test against malaria; instead, Artesunate is used
for the treatment of severe malaria and Artemisinin is used for uncomplicated
falciparum malaria. However, these treatments are not efficient against severe
malaria and improvements are needed. Primaquine (PQ) is one of the most widely
used antimalarial drugs. It is the only available drug to date for combating the
relapsing form of malaria. Nevertheless, it has severe side effects. Particle
drug-delivery systems present the ability to enhance the therapeutic properties
of drugs and decrease their side effects. Here, we report the development of
Polymeric Primaquine Microparticles (PPM) labeled with 99mTc for therapeutic
strategy against malaria infection. The amount of primaquine encapsulated into
the PPM was 79.54%. PPM presented a mean size of 929.47 ± 37.72 nm, with a PDI
of 0.228 ± 0.05 showing a homogeneous size for the microparticles and a
monodispersive behavior. Furthermore, the biodistribution test showed that
primaquine microparticles have a high liver accumulation. In vivo experiments
using mice show that the PPM treatments resulted in partial efficacy and
protection against the development of the parasite compared to free Primaquine.
These results suggest that microparticles drug delivery systems of primaquine
could be a possible approach for malaria prevention and treatment. Hemolytic toxicity caused by primaquine (PQ) is a high-risk condition that
hampers the wide use of PQ to treat liver-stage malaria. This study demonstrated
that phospholipid-free small unilamellar vesicles (PFSUVs) composed of Tween80
and cholesterol could encapsulate and deliver PQ to the hepatocytes with reduced
exposure to the red blood cells (RBCs). Nonionic surfactant (Tween80) and
cholesterol-forming SUVs with a mean diameter of 50 nm were fabricated for
delivering PQ. Drug release/retention, drug uptake by RBCs, pharmacokinetics,
and liver uptake of PFSUVs-PQ were evaluated in invitro and invivo models in
comparison to free drugs. Additionally, the stress effect on RBCs induced by
free PQ and PFSUVs-PQ was evaluated by examining RBC morphology. PFSUVs provided
>95% encapsulation efficiency for PQ at a drug-to-lipid ratio of 1:20 (w/w) and
stably retained the drug in the presence of serum. When incubated with RBCs, PQ
uptake in the PFSUVs group was reduced by 4- to 8-folds compared to free PQ. As
a result, free PQ induced significant RBC morphology changes, while PFSUVs-PQ
showed no such adverse effect. Intravenously (i.v.) delivered PFSUVs-PQ produced
a comparable plasma profile as free PQ, given i.v. and orally, while the liver
uptake was increased by 4.8 and 1.6-folds, respectively, in mice. Within the
liver, PFSUVs selectively targeted the hepatocytes, with no significant blood or
liver toxicity in mice. PFSUVs effectively targeted PQ to the liver and reduced
RBC uptake compared to free PQ, leading to reduced RBC toxicity. PFSUVs
exhibited potential in improving the efficacy of PQ for treating liver-stage
malaria. |
Which databases are devoted to 3D genome interactions? | 3DIV is a 3D-genome Interaction Viewer and database. The 3D Genome Browser is a web-based browser for visualizing 3D genome organization and long-range chromatin interactions. GMOL is an Interactive Tool for 3D Genome Structure Visualization. 3Disease Browser is a Web server for integrating 3D genome and disease-associated chromosome rearrangement data. The 3DGD is a database of genome 3D structure, that currently holds Hi-C data on four species, for easy accessing and visualization of chromatin 3D structure data. | Author information:
(1)Key Laboratory of Systems Biology, Shanghai Institutes for Biological
Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, P. R.
China, University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing
100049, National Center for Protein Science, Shanghai 333 Haike Road, Pudong
District, Shanghai 201210 and Shanghai Center for Bioinformation Technology,
1278 Keyuan Road, Shanghai 201203, P. R. ChinaKey Laboratory of Systems Biology,
Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320
Yue Yang Road, Shanghai 200031, P. R. China, University of Chinese Academy of
Sciences, 19A Yuquan Road, Beijing 100049, National Center for Protein Science,
Shanghai 333 Haike Road, Pudong District, Shanghai 201210 and Shanghai Center
for Bioinformation Technology, 1278 Keyuan Road, Shanghai 201203, P. R. China.
(2)Key Laboratory of Systems Biology, Shanghai Institutes for Biological
Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, P. R.
China, University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing
100049, National Center for Protein Science, Shanghai 333 Haike Road, Pudong
District, Shanghai 201210 and Shanghai Center for Bioinformation Technology,
1278 Keyuan Road, Shanghai 201203, P. R. China. Chromosomal rearrangement (CR) events have been implicated in many tumor and
non-tumor human diseases. CR events lead to their associated diseases by
disrupting gene and protein structures. Also, they can lead to diseases through
changes in chromosomal 3D structure and gene expression. In this study, we
search for CR-associated diseases potentially caused by chromosomal 3D structure
alteration by integrating Hi-C and ChIP-seq data. Our algorithm rediscovers
experimentally verified disease-associated CRs (polydactyly diseases) that alter
gene expression by disrupting chromosome 3D structure. Interestingly, we find
that intellectual disability may be a candidate disease caused by 3D chromosome
structure alteration. We also develop a Web server (3Disease Browser,
http://3dgb.cbi.pku.edu.cn/disease/) for integrating and visualizing
disease-associated CR events and chromosomal 3D structure. Three-dimensional (3D) chromatin structure is an emerging paradigm for
understanding gene regulation mechanisms. Hi-C (high-throughput chromatin
conformation capture), a method to detect long-range chromatin interactions,
allows extensive genome-wide investigation of 3D chromatin structure. However,
broad application of Hi-C data have been hindered by the level of complexity in
processing Hi-C data and the large size of raw sequencing data. In order to
overcome these limitations, we constructed a database named 3DIV (a 3D-genome
Interaction Viewer and database) that provides a list of long-range chromatin
interaction partners for the queried locus with genomic and epigenomic
annotations. 3DIV is the first of its kind to collect all publicly available
human Hi-C data to provide 66 billion uniformly processed raw Hi-C read pairs
obtained from 80 different human cell/tissue types. In contrast to other
databases, 3DIV uniquely provides normalized chromatin interaction frequencies
against genomic distance dependent background signals and a dynamic browsing
visualization tool for the listed interactions, which could greatly advance the
interpretation of chromatin interactions. '3DIV' is available at
http://kobic.kr/3div. Author information:
(1)Bioinformatics and Genomics Program, The Pennsylvania State University,
University Park, State College, PA, 16802, USA.
(2)Department of Biochemistry and Molecular Biology, College of Medicine, The
Pennsylvania State Hershey, Hershey, PA, 17033, USA.
(3)Department of Computer and Information Science, University of Pennsylvania,
Philadelphia, PA, 19104, USA.
(4)Department of Genetics, The Edison Family Center for Genome Sciences and
Systems Biology, Washington University School of Medicine, St. Louis, MO, 63108,
USA.
(5)Department of Genetics, University of North Carolina, Chapel Hill, NC, 27599,
USA.
(6)Department of Biostatistics, University of North Carolina, Chapel Hill, NC,
27599, USA.
(7)Department of Computer Science, University of North Carolina, Chapel Hill,
NC, 27599, USA.
(8)Department of Quantitative Health Sciences, Lerner Research Institute,
Cleveland Clinic Foundation, Cleveland, OH, 44195, USA.
(9)Center for Computational Biology and Bioinformatics, Huck Institutes of the
Life Sciences, The Pennsylvania State University, University Park, State
College, PA, 16802, USA.
(10)Department of Genetics, The Edison Family Center for Genome Sciences and
Systems Biology, Washington University School of Medicine, St. Louis, MO, 63108,
USA. [email protected].
(11)Bioinformatics and Genomics Program, The Pennsylvania State University,
University Park, State College, PA, 16802, USA. [email protected].
(12)Department of Biochemistry and Molecular Biology, College of Medicine, The
Pennsylvania State Hershey, Hershey, PA, 17033, USA. [email protected]. |
Where does REGN5458 bind to? | The bispecific antibody REGN5458 binds to B-cell maturation antigen (BCMA) and CD3. | |
Do mutations in KCNT2 only cause phenotypes with epilepsy? | No. There is a report of pathogenic variants in KCNT2 causing a developmental phenotype without epilepsy. | |
Is there an association between pyostomatitis vegetans and Crohn's disease? | Yes. Pyostomatitis vegetans (PV) is a rare condition characterized by pustules that affect the oral mucosa. It is a highly specific marker for inflammatory bowel disease and its correct recognition may lead to the diagnosis of ulcerative colitis or Crohn's disease. | Pyostomatitis vegetans is a rare disease of the oral cavity with characteristic
clinical and histopathological findings. Its importance lies in its high
correlation with inflammatory diseases of the intestinal tract. The present case
report and a review of the literature are taken as a basis to discuss the
disease as an entity. Pyostomatitis vegetans is a specific marker for ulcerative
colitis and Crohn's disease. Oral features of Crohn's disease include ulcers, lip fissuring, cobblestone
plaques, angular cheilitis, polypoid lesions, and perioral erythema.
Pyostomatitis vegetans is a rare eruption of the oral mucosa characterized by
tiny yellow pustules. It is considered a marker for inflammatory bowel disease.
We describe a 45-year-old woman with a 6-month history of painful sores in her
mouth, diarrhea, weight loss, and cutaneous lesions. Oral examination revealed
cobblestone plaques and indentation on the tongue and friable vegetating
pustules on the labial commissures. Staphylococcus simulans was isolated from
the pustules. Laboratory studies revealed leucocytosis, eosinophilia, and low
hemoglobin and zinc levels. Histologic study of the labial lesions revealed
hyperplastic epithelium with intraepithelial clefts that contain eosinophils and
neutrophils. Tongue lesions showed chronic inflammation with noncaseating
granulomas. Later, colonoscopy and biopsy demonstrated Crohn's disease of the
anorectal region. Pyostomatitis vegetans lesions regressed after oral zinc
supplementation. Prednisone treatment resulted in healing of the tongue lesions.
In our patient, pyostomatitis vegetans appeared to be related to zinc deficiency
that may have been caused by malabsorption. The pathogenetic interrelationship
between pyostomatitis vegetans and Crohn's disease is discussed. HISTORY AND CLINICAL FINDINGS: A 27-year-old man was referred to the
dermatological out-patient clinic because of inflammatory changes in the oral
mucosa of unknown cause. 5 months earlier he had been diagnosed as having
Crohn's disease of the terminal ileum. On both sides of the buccal mucosa there
were rough erythematous vegetations and disseminated miliary abscesses, which
extended to the labial gingiva and the soft palate. Further physical examination
was unremarkable.
INVESTIGATIONS: Several inflammatory parameters were increased: C-reactive
protein 100 mg/l, erythrocyte sedimentation rate 55/88 mm, eosinophilic cationic
protein 35.8 ng/ml (normal range 2.3-16 ng/ml). White cell count was normal
(7,25/nl), with a lymphocytopenia of 11.9%. There was no eosinophilia.
Haemoglobin was reduced to 11.6 g/dl and the platelets raised to 526/nl. Smears
of the oral mucosa showed no fungal, viral or bacterial infection. Biopsy
revealed leucocytic microabscesses in the epithelium, granulation tissue and
flat ulcerations with adjoining superficial necrotic zones.
DIAGNOSIS, TREATMENT AND COURSE: The clinical and histological picture as well
as the association with Crohn's disease (CD) suggested pyostomatitis vegetans
(PV). The PV was treated with disinfectant mouth washes which improved the
subjective findings. Budesonide was given for CD.
CONCLUSION: PV is a rare and usually isolated condition, but it can also occur
in association with a chronic gastrointestinal disease such as ulcerative
colitis and Crohn's disease. The diagnosis of PV indicates a thorough
gastroenterological investigation. BACKGROUND: Pyostomatitis-pyodermatitis vegetans is an uncommon condition
associated with chronic inflammatory bowel disease in 75% of the cases, usually
hemorrhagic rectocolitis.
CASE REPORT: A 48-year-old man was referred for recent development of pustulous
lesions of the lips and buccal mucosa and weight loss. He complained of
abdominal pain and intermittent diarrhea which had persisted for more than one
year. During the last three months, a pseudotumoral plaque with a pustulous rim
had developed over the two distal phalanxes of the right middle finger in
association with ungueal lysis and nodular, vegetating and crusted lesions on
the lateral aspect of the left arm. Small pustules covered the entire buccal
mucosa excepting the tongue and the glans forming a typical snail trace aspect.
Bacterial and mycological samples were negative. The histology reports for skin
and mucosa were similar: epithelial hyperplasia, intra- and subepithelial
granulocyte micro-abscesses and polymorphous infiltration of the superficial
derma with numerous neutrophils and eosinophils. There was a discrete
interkeratinocytic fluorescence at direct immunofluorescence but indirect
immunofluorescence was negative. Anti-desmogleine 1 immunolabeling showed
typical normal skin uptake and immunotransfer was negative. Digestive tract
endoscopy and histopathology examination of the bowel specimens confirmed the
diagnosis of Crohn's disease. Clinical manifestations improved dramatically with
prednisone.
DISCUSSION: This case of pyostomatitis-pyodermatitis vegetans involved several
aspects rarely reported in the literature: a) the cutaneomucosal signs were
inaugural; b) the association with Crohn's disease; c) the presence of lesions
to the genital mucosa; d) the unusual localization of the inaugural skin
manifestations. This clinical entity has now been clearly distinguished from
pemphigus vegetans. There was however a long debate on the similar clinical,
histological and even immunological expressions. We suggest that
pyostomatitis-pyodermatitis vegetans belongs to the spectrum of neutrophilic
dermatoses and other authors even propose it is a clinical form of pyoderma
gangrenosum. A 35-year-old woman with severe fistulizing Crohn's disease presented with
pyostomatitis vegetans affecting both the mouth and the vulva. The coalescing
pustules transformed within several days into vegetating lesions on areas of
inflammation. Microbial assessments revealed no pathogenic agent. Histology
showed neutrophilic microabscesses, but no granulomas. Three injections of
infliximab and maintece therapy with methotrexate resulted in rapid and
complete regression of both the pyostomatitis vegetans and the Crohn's disease.
Infliximab and methotrexate may be a promising treatment for the rare cases of
pyostomatitis vegetans associated with Crohn's disease. Inflammatory bowel disease (IBD) comprises two chronic, tissue-destructive,
clinical entities: Crohn's disease (CD) and ulcerative colitis (UC), both
immunologically based. Bowel symptoms are predomit, but extra-intestinal
complications may occur, including involvement of the oral cavity. Oral
involvement during IBD includes several types of lesions: the most common are
aphthae; uncommon lesions include, among others, pyostomatitis vegetans and
granulomatous lesions of CD. Starting with a presentation of six patients with
oral manifestations, which were crucial for the final diagnosis of IBD, a review
on the subject is presented. Oral involvement in IBD may be previous or
simultaneous to the gastrointestinal symptoms. However, in the majority of
cases, bowel disease precedes the onset of oral lesions by months or years. In
many patients, the intestinal symptoms may be minimal and can go undetected;
thus, most authors believe that the bowel must be thoroughly examined in all
patients with suspected IBD even in the absence of specific symptoms. Usually,
the clinical course of oral lesions is parallel to the activity of IBD;
therefore, oral manifestations are a good cutaneous marker of IBD. Pyostomatitis vegetans (PV) is a rare, chronic mucocutaneous disorder associated
with inflammatory bowel disease (IBD). Oral lesions of PV are distinct and
present as multiple white or yellow pustules with an erythematous base that
coalesce and undergo necrosis to form a typical "snail tracks" appearance. Two
cases of PV associated with IBD--one with Crohn's disease (CD) and the other
with ulcerative colitis (UC) are reported. In the first case, adalimumab therapy
brought the oral and gastrointestinal manifestations to complete remission. In
the second case, the remission was achieved with systemic steroid therapy, but
the disease relapsed after therapy discontinuation. Azathioprine was added
leading to sustained remission of PV. Because of persistent active intestinal
manifestation of UC, in spite of immunosuppressive therapy, infliximab was
introduced. With the therapy remission of intestinal manifestation of UC was
achieved as well. Our cases confirm previously reported good experience with
immunomodulators and biologics in the treatment of PV. But, before using them we
have to exclude an infectious etiology of oral lesions. Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and
ulcerative colitis, not only affect the intestinal tract but also have an
extraintestinal involvement within the oral cavity. These oral manifestations
may assist in the diagnosis and the monitoring of disease activity, whilst
ignoring them may lead to an inaccurate diagnosis and useless and expensive
workups. Indurated tag-like lesions, cobblestoning, and mucogingivitis are the
most common specific oral findings encountered in CD cases. Aphthous stomatitis
and pyostomatitis vegetans are among non-specific oral manifestations of IBD. In
differential diagnosis, side effects of drugs, infections, nutritional
deficiencies, and other inflammatory conditions should also be considered.
Treatment usually involves managing the underlying intestinal disease. In severe
cases with local symptoms, topical and/or systemic steroids and
immunosuppressive drugs might be used. The incidence of inflammatory bowel diseases (IBD) - Crohn's disease (CD) and
ulcerative colitis (UC) - has been increasing on a global scale, and
progressively, more gastroenterologists will be included in the diagnosis and
treatment of IBD. Although IBD primarily affects the intestinal tract,
extraintestinal manifestations of the disease are often apparent, including in
the oral cavity, especially in CD. Specific oral manifestations in patients with
CD are as follows: indurate mucosal tags, cobblestoning and mucogingivitis, deep
linear ulcerations and lip swelling with vertical fissures. The most common
non-specific manifestations, such as aphthous stomatitis and angular cheilitis,
occur in both diseases, while pyostomatitis vegetans is more pronounced in
patients with UC. Non-specific lesions in the oral cavity can also be the result
of malnutrition and drugs. Malnutrition, followed by anemia and mineral and
vitamin deficiency, affects the oral cavity and teeth. Furthermore, all of the
drug classes that are applied to the treatment of inflammatory bowel diseases
can lead to alterations in the oral cavity due to the direct toxic effects of
the drugs on oral tissues, as well as indirect immunosuppressive effects with a
risk of developing opportunistic infections or bone marrow suppression. There is
a higher occurrence of maligt diseases in patients with IBD, which is related
to the disease itself and to the IBD-related therapy with a possible oral
pathology. Treatment of oral lesions includes treatment of the alterations in
the oral cavity according to the etiology together with treatment of the primary
intestinal disease, which requires adequate knowledge and a strong cooperation
between gastroenterologists and specialists in oral medicine. BACKGROUND: Over recent decades, both the incidence and prevalence of chronic
inflammatory bowel disease have continued to rise in industrialized countries;
the disease is frequently associated with extracutaneous involvement and
comorbidity.
OBJECTIVES: The purpose of this work was to investigate the frequency and
specificity of mucocutaneous manifestations in Crohn's disease (CD) and
ulcerative colitis (UC).
MATERIALS AND METHODS: An extensive search in peer-reviewed journals via PubMed
was performed; presented is a summary and analysis of various studies and data,
including data of patients treated at our department.
RESULTS: CD and UC are frequently associated with mucocutaneous symptoms;
however, primary/specific disease-associations are exclusively seen in CD
patients. These include peri-anal and -stomal fistulas and ulcerations,
"metastatic" Crohn's disease as well as oral granulomatous disease. Moreover, in
both CD and UC, there occur several other inflammatory skin conditions such as
erythema nodosum, pyoderma gangrenosum, hidradenitis suppurativa, chronic oral
aphthous disease, Sweet syndrome, pyostomatitis vegetans, and bowel-associated
dermatosis-arthritis syndrome. Malnutrition syndromes (zinc and vitamin
deficiencies) are only rarely observed.
CONCLUSION: On skin and oral/genital mucous membranes various different
inflammatory manifestations may be observed during the course of CD or UC.
However, most data about a direct pathogenic relationship of the
gastrointestinal and dermatologic disorders are quite heterogeneous or even
contradictory. Nevertheless, knowledge of these conditions and their possible
association with CD and UC could be crucial for early diagnosis and initiation
of an appropriate therapy and thus be essential to prevent secondary tissue
damage. Pyostomatitis vegetans is a very rare oral manifestation with unknown
pathogenesis. Skin and other mucous membrane involvement may be seen. This
lesion has strong association with Inflammatory Bowel Disease (IBD) and may be
the first sign of it. The management of Pyostomatitis vegetans is usually based
on the management of underlying bowel disease. We present a case of
Pyostomatitis vegetans involving gingiva and oral mucosa with no skin lesion
which led to the diagnosis of Crohn's disease to emphasize important role of
dentists in diagnosis of rare oral lesions and management of patients' systemic
disease. Pyostomatitis vegetans is a disease of the gingiva and the oral mucosa with
noticeable, uncommon morphology. Clinical characteristics of this rare disease
and considerations regarding differential diagnosis are described. Pyostomatitis
vegetans is frequently associated with chronic inflammatory bowel diseases and
can, thus, give a diagnostic hint at an existing ulcerative colitis or Crohns
disease. A therapy plan for pyostomatitis vegetans is presented, which led to
remission using local treatment only. The follow-up examination after one year
showed that the treatment outcome had remained stable. An unexpected clinical
appearance of the gingiva with small, pale pink thickenings after therapy and at
follow-up is portrayed. |
Is serotonin transported by platelets? | Yes,
platelets transport serotonin. | Autism spectrum disorder (ASD) is a clinically heterogeneous neurodevelopmental
disorder that is caused by gene-environment interactions. To improve its
diagnosis and treatment, numerous efforts have been undertaken to identify
reliable biomarkers for autism. None of them have delivered the holy grail that
represents a reproducible, quantifiable, and sensitive biomarker. Though blood
platelets are mainly known to prevent bleeding, they also play pivotal roles in
cancer, inflammation, and neurological disorders. Platelets could serve as a
peripheral biomarker or cellular model for autism as they share common
biological and molecular characteristics with neurons. In particular,
platelet-dense granules contain neurotransmitters such as serotonin and
gamma-aminobutyric acid. Molecular players controlling granule formation and
secretion are similarly regulated in platelets and neurons. The major platelet
integrin receptor αIIbβ3 has recently been linked to ASD as a regulator of
serotonin transport. Though many studies revealed associations between platelet
markers and ASD, there is an important knowledge gap in linking these markers
with autism and explaining the altered platelet phenotypes detected in autism
patients. The present review enumerates studies of different biomarkers detected
in ASD using platelets and highlights the future needs to bring this research to
the next level and advance our understanding of this complex disorder. Calcification, fibrosis, and chronic inflammation are the predomit features
of calcific aortic valve disease, a life-threatening condition. Drugs that
induce serotonin (5-hydroxytryptamine [5-HT]) are known to damage valves, and
activated platelets, which carry peripheral serotonin, are known to promote
calcific aortic valve stenosis. However, the role of 5-HT in valve leaflet
pathology is not known. We tested whether serotonin mediates
inflammation-induced matrix mineralization in valve cells. Real-time reverse
transcription-polymerase chain reaction analysis showed that murine aortic valve
interstitial cells (VICs) expressed both serotonin receptor types 2A and 2B
(Htr2a and Htr2b). Although Htr2a expression was greater at baseline, Htr2b
expression was induced several-fold more than Htr2a in response to the
pro-calcific tumor necrosis factor-α (TNF-α) treatment. 5-HT also augmented
TNF-α-induced osteoblastic differentiation and matrix mineralization of VIC, but
5-HT alone had no effects. Inhibition of serotonin receptor type 2B, using
specific inhibitors or lentiviral knockdown in VIC, attenuated 5-HT effects on
TNF-α-induced osteoblastic differentiation and mineralization. 5-HT treatment
also augmented TNF-α-induced matrix metalloproteinase-3 expression, which was
also attenuated by Htr2b knockdown. Htr2b expression in aortic roots and serum
levels of peripheral 5-HT were also greater in the hyperlipidemic Apoe-/- mice
than in control normolipemic mice. These findings suggest a new role for
serotonin signaling in inflammation-induced calcific valvulopathy. The serotonergic system, serotonin (5HT), serotonin transporter (SERT), and
serotonin receptors (5HT-x), is an evolutionarily ancient system that has clear
physiological advantages to all life forms from bacteria to humans. This review
focuses on the role of platelet/plasma serotonin and the cardiovascular system
with minor references to its significant neurotransmitter function. Platelets
transport and store virtually all plasma serotonin in dense granules. Stored
serotonin is released from activated platelets and can bind to serotonin
receptors on platelets and cellular components of the vascular wall to augment
aggregation and induce vasoconstriction or vasodilation. The vascular
endothelium is critical to the maintece of cardiovascular homeostasis. While
there are numerous ligands, neurological components, and baroreceptors that
effect vascular tone it is proposed that serotonin and nitric oxide (an
endothelium relaxing factor) are major players in the regulation of systemic
blood pressure. Signals not fully defined, to date, that direct serotonin
binding to one of the 15 identified 5HT receptors versus the transporter, and
the role platelet/plasma serotonin plays in regulating hypertension within the
cardiovascular system remain important issues to better understand many diseases
and to develop new drugs. Also, expanded research of these pathways in lower
life-forms may serve as important model systems to further our understanding of
the evolution and mechanisms of action of serotonin. |
Proteins in the karyopherin family (Kaps) are associated with what cellular process? | Nuclear translocation of large proteins is mediated through specific protein carriers, collectively named karyopherins (importins, exportins and adaptor proteins) | The alpha- and beta-karyopherins (Kaps), also called importins, mediate the
nuclear transport of proteins. All alpha-Kaps contain a central domain composed
of eight approximately 40 amino acid, tandemly arranged, armadillo-like (Arm)
repeats. The number and order of these repeats have not changed since the common
origin of fungi, plants, and mammals. Phylogenetic analysis suggests that the
various alpha-Kaps fall into two groups, alpha1 and alpha2. Whereas animals
encode both types, the yeast genome encodes only an alpha1-Kap. The beta-Kaps
are characterized by 14-15 tandemly arranged HEAT motifs. We show that the Arm
repeats of alpha-Kaps and the HEAT motifs of beta-Kaps are similar, suggesting
that the alpha-Kaps and beta-Kaps (and for that matter, all Arm and HEAT
repeat-containing proteins) are members of the same protein superfamily.
Phylogenetic analysis indicates that there are at least three major groups of
beta-Kaps, consistent with their proposed cargo specificities. We present a
model in which an alpha-independent beta-Kap progenitor gave rise to the
alpha-dependent beta-Kaps and the alpha-Kaps. Binding of the TATA-binding protein (TBP) to the promoter is the first and rate
limiting step in the formation of transcriptional complexes. We show here that
nuclear import of TBP is mediated by a new karyopherin (Kap) (importin) family
member, Kap114p. Kap114p is localized to the cytoplasm and nucleus. A complex of
Kap114p and TBP was detected in the cytosol and could be reconstituted using
recombit proteins, suggesting that the interaction was direct. Deletion of
the KAP114 gene led to specific mislocalization of TBP to the cytoplasm. We also
describe two other potential minor import pathways for TBP. Consistent with
other Kaps, the dissociation of TBP from Kap114p is dependent on RanGTP.
However, we could show that double stranded, TATA-containing DNA stimulates this
RanGTP-mediated dissociation of TBP, and is necessary at lower RanGTP
concentrations. This suggests a mechanism where, once in the nucleus, TBP is
preferentially released from Kap114p at the promoter of genes to be transcribed.
In this fashion Kap114p may play a role in the intranuclear targeting of TBP. The first step in the assembly of new chromatin is the cell cycle-regulated
synthesis and nuclear import of core histones. The core histones include H2A and
H2B, which are assembled into nucleosomes as heterodimers. We show here that the
import of histone H2A and H2B is mediated by several members of the karyopherin
(Kap; importin) family. An abundant complex of H2A, H2B, and Kap114p was
detected in cytosol. In addition, two other Kaps, Kap121p and Kap123p, and the
histone chaperone Nap1p were isolated with H2A and H2B. Nap1p is not necessary
for the formation of the Kap114p-H2A/H2B complex or for import of H2A and H2B.
We demonstrate that both histones contain a nuclear localization sequence (NLS)
in the amino-terminal tail. Fusions of the NLSs to green fluorescent protein
were specifically mislocalized to the cytoplasm in kap mutant strains. In
addition, we detected a specific mislocalization in a kap95
temperature-sensitive strain, suggesting that this Kap is also involved in the
import of H2A and H2B in vivo. Importantly, we show that Kap114p, Kap121p, and
Kap95 interact directly with both histone NLSs and that RanGTP inhibits this
association. These data suggest that the import of H2A and H2B is mediated by a
network of Kaps, in which Kap114p may play the major role. Human karyopherin alpha2 (KPNA2), a member of the karyopherin alpha family,
plays a key role in the nuclear import of proteins with a classical nuclear
localization signal (NLS). KPNA2, as part of a karyopherin alpha-beta
heterodimer, directly binds to the NLS of proteins and functions as an adaptor
that binds NLS-containing proteins via karyopherin beta to the nuclear pore
complex. The NLS protein-receptor complex is translocated through the pore by an
energy-dependent mechanism. Recently, we have identified and mapped the gene for
KPNA2 in close proximity to a translocation breakpoint within 17q23-q24
associated with Russell-Silver syndrome (RSS). Therefore, we considered KPNA2 as
a positional candidate gene for this heterogeneous disorder. RSS is mainly
characterized by pre- and postnatal growth retardation, lateral asymmetry, and
other dysmorphic features. Here, we present the genomic organization of the
human KPNA2 gene with 11 exons spanning approximately 10 kb on chromosome
17q23-q24. Screening for mutations within all exons and adjacent intronic
sequences from 31 unrelated RSS patients revealed three single nucleotide
polymorphisms (SNPs) in exons 1, 5, and 7, and five SNPs in introns 1, 4 (2
SNPs), 8, and 9, respectively. No disease-related mutation was identified by
comparing the sequence data of the RSS patients with their clinically normal
parents and controls. In yeast there are at least 14 members of the beta-karyopherin protein family
that govern the movement of a diverse set of cargoes between the nucleus and
cytoplasm. Knowledge of the cargoes carried by each karyopherin and insight into
the mechanisms of transport are fundamental to understanding constitutive and
regulated transport and elucidating how they impact normal cellular functions.
Here, we have focused on the identification of nuclear import cargoes for the
essential yeast beta-karyopherin, Kap121p. Using an overlay blot assay and
coimmunopurification studies, we have identified 30 putative Kap121p cargoes.
Among these were Nop1p and Sof1p, two essential trans-acting protein factors
required at the early stages of ribosome biogenesis. Characterization of the
Kap121p-Nop1p and Kap121p-Sof1p interactions demonstrated that, in addition to
lysine-rich nuclear localization signals (NLSs), Kap121p recognizes a unique
class of signals distinguished by the abundance of arginine and glycine residues
and consequently termed rg-NLSs. Kap104p is also known to recognize rg-NLSs, and
here we show that it compensates for the loss of Kap121p function. Sof1p is also
transported by Kap121p; however, its import can be mediated by a piggyback
mechanism with Nop1p bridging the interaction between Sof1p and Kap121p.
Together, our data elucidate additional levels of complexity in these nuclear
transport pathways. Many cargoes destined for nuclear import carry nuclear localization signals that
are recognized by karyopherins (Kaps). We present methods to quantitate import
rates and measure Kap and cargo concentrations in single yeast cells in vivo,
providing new insights into import kinetics. By systematically manipulating the
amounts, types, and affinities of Kaps and cargos, we show that import rates in
vivo are simply governed by the concentrations of Kaps and their cargo and the
affinity between them. These rates fit to a straightforward pump-leak model for
the import process. Unexpectedly, we deduced that the main limiting factor for
import is the poor ability of Kaps and cargos to find each other in the
cytoplasm in a background of overwhelming nonspecific competition, rather than
other more obvious candidates such as the nuclear pore complex and Ran. It is
likely that most of every import round is taken up by Kaps and nuclear
localization signals sampling other cytoplasmic proteins as they locate each
other in the cytoplasm. Proteins in the karyopherin-β family mediate the majority of macromolecular
transport between the nucleus and the cytoplasm. Eleven of the 19 known human
karyopherin-βs and 10 of the 14S. cerevisiae karyopherin-βs mediate nuclear
import through recognition of nuclear localization signals or NLSs in their
cargos. This receptor-mediated process is essential to cellular viability as
proteins are translated in the cytoplasm but many have functional roles in the
nucleus. Many known karyopherin-β-cargo interactions were discovered through
studies of the individual cargos rather than the karyopherins, and this
information is thus widely scattered in the literature. We consolidate
information about cargos that are directly recognized by import-karyopherin-βs
and review common characteristics or lack thereof among cargos of different
import pathways. Knowledge of karyopherin-β-cargo interactions is also critical
for the development of nuclear import inhibitors and the understanding of their
mechanisms of inhibition. This article is part of a Special Issue entitled:
Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein
Import. Nucleocytoplasmic transport occurs through the nuclear pore complex (NPC), which
in yeast is a ~50 MDa complex consisting of ~30 different proteins. Small
molecules can freely exchange through the NPC, but macromolecules larger than
~40 kDa must be aided across by transport factors, most of which belong to a
related family of proteins termed karyopherins (Kaps). These transport factors
bind to the disordered phenylalanine-glycine (FG) repeat domains in a family of
NPC proteins termed FG nups, and this specific binding allows the transport
factors to cross the NPC. However, we still know little in terms of the
molecular and kinetic details regarding how this binding translates to selective
passage of transport factors across the NPC. Here we show that the specific
interactions between Kaps and FG nups are strongly modulated by the presence of
a cellular milieu whose proteins appear to act as very weak competitors that
nevertheless collectively can reduce Kap/FG nup affinities by several orders of
magnitude. Without such modulation, the avidities between Kaps and FG nups
measured in vitro are too tight to be compatible with the rapid transport
kinetics observed in vivo. We modeled the multivalent interactions between the
disordered repeat binding sites in the FG nups and multiple cognate binding
sites on Kap, showing that they should indeed be sensitive to even weakly
binding competitors; the introduction of such competition reduces the
availability of these binding sites, dramatically lowering the avidity of their
specific interactions and allowing rapid nuclear transport. The karyopherin (Kap) family of nuclear transport factors facilitates
macromolecular transport through nuclear pore complexes (NPCs). The binding of
Kaps to their cargos can also regulate, both temporally and spatially, the
interactions of the cargo protein with interacting partners. Here, we show that
the essential yeast Kap, Kap121, binds Dam1 and Duo1, components of the
microtubule (MT)-associated Dam1 complex required for linking dynamic MT ends
with kinetochores (KTs). Like mutations in the Dam1 complex, loss of Kap121
function compromises the formation of normal KT-MT attachments during mitosis.
We show that the stability of the Dam1 complex in vivo is dependent on its
association with Kap121. Furthermore, we show that the Kap121/Duo1 complex is
maintained in the presence of RanGTP but Kap121 is released by the cooperative
actions of RanGTP and tubulin. We propose that Kap121 stabilizes the Dam1
complex and participates in escorting it to spindle MTs. Nuclear import of proteins relies on nuclear import receptors called
importins/karyopherins (Kaps), whose functions were reported in yeasts, fungi,
plants, and animal cells, including cell cycle control, morphogenesis, stress
sensing/response, and also fungal pathogenecity. However, limited is known about
the physiological function and regulatory mechanism of protein import in the
rice-blast fungus Magnaporthe oryzae. Here, we identified an ortholog of
β-importin in M. oryzae encoded by an ortholog of KAP119 gene. Functional
characterisation of this gene via reverse genetics revealed that it is required
for vegetative growth, conidiation, melanin pigmentation, and pathogenicity of
M. oryzae. The mokap119Δ mutant was also defective in formation of
appressorium-like structure from hyphal tips. By affinity assay and liquid
chromatography-tandem mass spectrometry, we identified potential
MoKap119-interacting proteins and further verified that MoKap119 interacts with
the cyclin-dependent kinase subunit MoCks1 and mediates its nuclear import.
Transcriptional profiling indicated that MoKap119 may regulate transcription of
infection-related genes via MoCks1 regulation of MoSom1. Overall, our findings
provide a novel insight into the regulatory mechanism of M. oryzae pathogenesis
likely by MoKap119-mediated nuclear import of the cyclin-dependent kinase
subunit MoCks1. In eukaryotic cells, nucleocytoplasmic trafficking of macromolecules is largely
mediated by Karyopherin β/Importin (KPNβ or Impβ) nuclear transport factors, and
they import and export cargo proteins or RNAs via the nuclear pores across the
nuclear envelope, consequently effecting the cellular signal cascades in
response to pathogen attack and environmental cues. Although achievements on
understanding the roles of several KPNβs have been obtained from model plant
Arabidopsis thaliana, comprehensive analysis of potato KPNβ gene family is yet
to be elucidated. In our genome-wide identifications, a total of 13 StKPNβ
(Solanum tuberosum KPNβ) genes were found in the genome of the doubled monoploid
S. tuberosum Group Phureja DM1-3. Sequence alignment and conserved domain
analysis suggested the presence of importin-β N-terminal domain (IBN_N, PF08310)
or Exporin1-like domain (XpoI, PF08389) at N-terminus and HEAT motif at the
C-terminal portion in most StKPNβs. Phylogenetic analysis indicated that members
of StKPNβ could be classified into 16 subgroups in accordance with their
homology to human KPNβs, which was also supported by exon-intron structure,
consensus motifs, and domain compositions. RNA-Seq analysis and quantitative
real-time PCR experiments revealed that, except StKPNβ3d and StKPNβ4, almost all
StKPNβs were ubiquitously expressed in all tissues analyzed, whereas
transcriptional levels of several StKPNβs were increased upon biotic/abiotic
stress or phytohormone treatments, reflecting their potential roles in plant
growth, development or stress responses. Furthermore, we demonstrated that
silencing of StKPNβ3a, a SA- and H2O2-inducible KPNβ genes led to increased
susceptibility to environmental challenges, implying its crucial roles in plant
adaption to abiotic stresses. Overall, our results provide molecular insights
into StKPNβ gene family, which will serve as a strong foundation for further
functional characterization and will facilitate potato breeding programs. The transport of histones from the cytoplasm to the nucleus of the cell, through
the nuclear membrane, is a cellular process that regulates the supply of new
histones in the nucleus and is key for DNA replication and transcription.
Nuclear import of histones is mediated by proteins of the karyopherin family of
nuclear transport receptors. Karyopherins recognize their cargos through linear
motifs known as nuclear localization/export sequences or through folded domains
in the cargos. Karyopherins interact with nucleoporins, proteins that form the
nuclear pore complex, to promote the translocation of their cargos into the
nucleus. When binding to histones, karyopherins not only function as nuclear
import receptors but also as chaperones, protecting histones from non-specific
interactions in the cytoplasm, in the nuclear pore and possibly in the nucleus.
Studies have also suggested that karyopherins might participate in histones
deposition into nucleosomes. In this review we describe structural and
biochemical studies from the last two decades on how karyopherins recognize and
transport the core histone proteins H3, H4, H2A and H2B and the linker histone
H1 from the cytoplasm to the nucleus, which karyopherin is the major nuclear
import receptor for each of these histones, the oligomeric state of histones
during nuclear import and the roles of post-translational modifications,
histone-chaperones and RanGTP in regulating these nuclear import pathways. BACKGROUND: Nuclear translocation of large proteins is mediated through specific
protein carriers, collectively named karyopherins (importins, exportins and
adaptor proteins). Cargo proteins are recognized by importins through specific
motifs, known as nuclear localization signals (NLS). However, only the NLS
recognized by importin α and transportin (M9 NLS) have been identified so far
METHODS: An unsupervised in silico approach was used, followed by experimental
validation.
RESULTS: We identified the sequence EKRKI(E/R)(K/L/R/S/T) as an NLS signal for
importin 7 recognition. This sequence was validated in the breast cancer cell
line T47D, which expresses importin 7. Finally, we verified that importin
7-mediated nuclear protein transport is affected by cargo protein
phosphorylation.
CONCLUSIONS: The NLS sequence for importin 7 was identified and we propose this
approach as an identification method of novel specific NLS sequences for
β-karyopherin family members.
GENERAL SIGNIFICANCE: Elucidating the complex relationships of the nuclear
transporters and their cargo proteins may help in laying the foundation for the
development of novel therapeutics, targeting specific importins, with an
immediate translational impact. Karyopherins mediate the macromolecular transport between the cytoplasm and the
nucleus and participate in cancer progression. However, the role and mechanism
of importin-11 (IPO11), a member of the karyopherin family, in glioma
progression remain undefined. Effects of IPO11 on glioma progression were
detected using CCK-8, colony formation assay, flow cytometry analysis, caspase-3
activity assay, and Transwell invasion assay. Western blot analysis was used to
detect the expression of active caspase-3, active caspase-7, active caspase-9,
N-cadherin, Vimentin, E-cadherin, β-catenin, and c-Myc. The activity of
Wnt/β-catenin pathway was evaluated by the T-cell factor/lymphoid enhancer
factor (TCF/LEF) transcription factor reporter assay. Results showed that IPO11
knockdown inhibited proliferation and reduced colony number in glioma cells.
IPO11 silencing promoted the apoptotic rate, increased expression levels of
active caspase-3, caspase-7, and caspase-9, and enhanced caspase-3 activity.
Moreover, IPO11 silencing inhibited glioma cell invasion by suppressing
epithelial-to-mesenchymal transition (EMT). Mechanistically, IPO11 knockdown
inactivated the Wnt/β-catenin pathway. β-Catenin overexpression abolished the
effects of IPO11 silencing on the proliferation, apoptosis, and invasion in
glioma cells. Furthermore, IPO11 silencing blocked the maligt phenotypes and
repressed the Wnt/β-catenin pathway in vivo. In conclusion, IPO11 knockdown
suppressed the maligt phenotypes of glioma cells by inactivating the
Wnt/β-catenin pathway. Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest maligcies and
is known for its high resistance and low response to treatment. Tumor immune
evasion is a major stumbling block in designing effective anticancer therapeutic
strategies. Karyopherin alpha 2 (KPNA2), a member of the nuclear transporter
family, is elevated in multiple human cancers and accelerates carcinogenesis.
However, the specific role of KPNA2 in PDAC remains unclear. In this study, we
found that expression of KPNA2 was significantly upregulated in PDAC compared to
adjacent nontumor tissue and its high expression was correlated with poor
survival outcome by analyzing the GEO datasets. Similar KPNA2 expression pattern
was also found in both human patient samples and KPC mouse models through IHC
staining. Although KPNA2 knockdown failed to impair the vitality and migration
ability of PDAC cells in vitro, the in vivo tumor growth was significantly
impeded and the expression of immune checkpoint ligand PD-L1 was reduced by
silencing KPNA2. Furthermore, we uncovered that KPNA2 modulated the expression
of PD-L1 by mediating nuclear translocation of STAT3. Collectively, our data
suggested that KPNA2 has the potential to serve as a promising biomarker for
diagnosis in PDAC. BACKGROUND: Karyopherin α-2 (KPNA2) is a member of karyopherin family, which is
proved to be responsible for the import or export of cargo proteins. Studies
have determined that KPNA2 is associated with the development and prognosis of
various cancers, yet the role of KPNA2 in ovarian carcinoma and its potential
molecular mechanisms remains unclear.
MATERIALS AND METHODS: The expression and prognosis of KPNA2 in ovarian cancer
was investigated using GEPIA and Oncomine analyses. Mutations of KPNA2 in
ovarian cancer were analyzed by cBioPortal database. The prognostic value of
KPNA2 expression was evaluated by our own ovarian carcinoma samples using
RT-qPCR. Subsequently, the cell growth, migration and invasion of ovarian cancer
cells were investigated by CCK-8 and transwell assay, respectively. The protein
levels of KPNA2 and KIF4A were determined by western blot.
RESULTS: We obtained the following important results. (1) KPNA2 and KIF4A
wereoverexpressed in ovairan cancer tissues and cells. (2) Among patients with
ovarian cancer, overexpressed KPNA2 was associated with lower survival rate. (3)
Mutations (R197* and S140F) in KPNA2 will have some influences on protein
structure, and then may cause protein function abnormal. (4) KPNA2 konckdown
inhibited proliferation, migration, invasion, as well as the expression of
KIF4A.
CONCLUSION: KPNA2, as a tumorigenic gene in ovarian cancer, accelerated tumor
progression by up-regulating KIF4A, suggesting that KPNA2 might be a hopeful
indicator of treatment and poor prognosis. |
What percentage of human genes have no introns? | About 3% of human genes have no introns. URL_0 | Nonsense-mediated decay (NMD), also called mRNA surveillance, is an
evolutionarily conserved pathway that degrades mRNAs that prematurely terminate
translation. To date, the pathway in mammalian cells has been shown to depend on
the presence of a cis-acting destabilizing element that usually consists of an
exon-exon junction generated by the process of pre-mRNA splicing. Whether or not
mRNAs that derive from naturally intronless genes, that is, mRNAs not formed by
the process of splicing, are also subject to NMD has yet to be investigated. The
possibility of NMD is certainly reasonable considering that mRNAs of
Saccharomyces cerevisiae are subject to NMD even though most derive from
naturally intronless genes. In fact, mRNAs of S. cerevisiae generally harbor a
loosely defined splicing-independent destabilizing element that has been
proposed to function in NMD analogously to the spliced exon-exon junction of
mammalian mRNAs. Here, we demonstrate that nonsense codons introduced into
naturally intronless genes encoding mouse heat shock protein 70 or human histone
H4 fail to elicit NMD. Failure is most likely because each mRNA lacks a
cis-acting destabilizing element, because insertion of a spliceable intron a
sufficient distance downstream of a nonsense codon within either gene is
sufficient to elicit NMD. Using computational approaches we have identified 2017 expressed intronless
genes in the mouse genome. Evolutionary analysis reveals that 56 intronless
genes are conserved among the three domains of life--bacteria, archea and
eukaryotes. These highly conserved intronless genes were found to be involved in
essential housekeeping functions. About 80% of expressed mouse intronless genes
have orthologs in eukaryotic genomes only, and thus are specific to eukaryotic
organisms. 608 of these genes have intronless human orthologs and 302 of these
orthologs have a match in OMIM database. Investigation into these mouse genes
will be important in generating mouse models for understanding human diseases. Intronless genes (IGs) fraction varies between 2.7 and 97.7% in eukaryotic
genomes. Although many databases on exons and introns exist, there was no
curated database for such genes which allowed their study in a concerted manner.
Such a database would be useful to identify the functional features and the
distribution of these genes across the genome. Here, a new database of IGs in
eukaryotes based on GenBank data was described. This database, called IGD
(Intronless Gene Database), is a collection of gene sequences that were
annotated and curated. The current version of IGD contains 687 human intronless
genes with their protein and CDS sequences. Some features of the entries are
given in this paper. Data was extracted from GenBank release 183 using a Perl
script. Data extraction was followed by a manual curation step. Intronless genes
were then analyzed based on their RefSeq annotation and Gene Ontology functional
class. IGD represents a useful resource for retrieval and in silico study of
intronless genes. IGD is available at http://www.bioinfo-cbs.org/igd with
comprehensive help and FAQ pages that illustrate the main uses of this resource. Intronless genes (IGs) constitute approximately 3% of the human genome. Human
IGs are essentially different in evolution and functionality from the IGs of
unicellular eukaryotes, which represent the majority in their genomes.
Functional analysis of IGs has revealed a massive over-representation of signal
transduction genes and genes encoding regulatory proteins important for growth,
proliferation, and development. IGs also often display tissue-specific
expression, usually in the nervous system and testis. These characteristics
translate into IG-associated diseases, mainly neuropathies, developmental
disorders, and cancer. IGs represent recent additions to the genome, created
mostly by retroposition of processed mRNAs with retained functionality.
Processing, nuclear export, and translation of these mRNAs should be hampered
dramatically by the lack of splice factors, which normally tightly cover mature
transcripts and govern their fate. However, natural IGs manage to maintain
satisfactory expression levels. Different mechanisms by which IGs solve the
problem of mRNA processing and nuclear export are discussed here, along with
their possible impact on reporter studies. Nucleosomes, the basic units of chromatin, are involved in transcription
regulation and DNA replication. Intronless genes, which constitute 3 percent of
the human genome, differ from intron-containing genes in evolution and function.
Our analysis reveals that nucleosome positioning shows a distinct pattern in
intronless and intron-containing genes. The nucleosome occupancy upstream of
transcription start sites of intronless genes is lower than that of
intron-containing genes. In contrast, high occupancy and well positioned
nucleosomes are observed along the gene body of intronless genes, which is
perfectly consistent with the barrier nucleosome model. Intronless genes have a
significantly lower expression level than intron-containing genes and most of
them are not expressed in CD4+ T cell lines and GM12878 cell lines, which
results from their tissue specificity. However, the highly expressed genes are
at the same expression level between the two types of genes. The highly
expressed intronless genes require a higher density of RNA Pol II in an
elongating state to compensate for the lack of introns. Additionally, 5' and 3'
nucleosome depleted regions of highly expressed intronless genes are deeper than
those of highly expressed intron-containing genes. |
What are the currently FDA approved monoclonal antibodies for myeloma? | The US Food and Drug Administration approved MoAbs, include belantamab mafodotin, daratumumab, elotuzumab, and isatuximab. | In the past several years, there have been significant advances in the
therapeutic arsenal of agents used to treat multiple myeloma (MM). Despite these
advances, MM remains incurable. One of the most recent therapeutic advances is
the development of targeted monoclonal antibodies (MoAbs). The MoAbs have
significantly improved disease response rates, and extended survival in MM
patients. In this review, we highlight the current US Food and Drug
Administration approved MoAbs, namely, belantamab mafodotin, daratumumab,
elotuzumab, and isatuximab. The mechanisms of action and pivotal clinical trials
that led to US Food and Drug Administration approval of these agents and their
current therapeutic use in the management of patients with MM are discussed in
detail. Lastly, we describe several novel MoAbs under clinical investigation
with potential for approval in the future. |
What is caused by biallelic variants in PCDHGC4? | Biallelic variants in PCDHGC4 cause a novel neurodevelopmental syndrome with progressive microcephaly, seizures, and joint anomalies. | Author information:
(1)Cologne Center for Genomics (CCG), University of Cologne and University
Hospital Cologne, Cologne, Germany.
(2)Institute of Biochemistry I, Medical Faculty, University of Cologne, Cologne,
Germany.
(3)Human Molecular Genetics Laboratory, Health Biotechnology Division, National
Institute for Biotechnology and Genetic Engineering (NIBGE) College, PIEAS,
Faisalabad, Pakistan.
(4)Department of Neuromuscular Disorders, UCL Institute of Neurology, London,
UK.
(5)Department of Medical Genetics, Ankara Bilkent City Hospital, Ankara, Turkey.
(6)Aix Marseille Univ, INSERM, MMG, Marseille, France.
(7)Assistance Publique-Hôpitaux de Marseille, Hôpital La Timone Enfants,
Département de Génétique Médicale, Marseille, France.
(8)Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW,
Australia.
(9)Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester
University NHS Foundation Trust, Health Innovation Manchester, Manchester, UK.
(10)Division of Evolution and Genomic Sciences, School of Biological Sciences,
Faculty of Biology, Medicine and Health, University of Manchester, Manchester,
UK.
(11)Department of Pediatrics, College of Medicine, Imam Abdulrahman Bin Faisal
University, Dammam, Saudi Arabia.
(12)Institute of Human Genetics, University Medical Center Göttingen, Göttingen,
Germany.
(13)Paediatric Genetic and Metabolic Service, Tawam Hospital, Al Ain, United
Arab Emirates.
(14)Department of Biological and Biomedical Sciences, Aga Khan University,
Karachi, Pakistan.
(15)Pakistan Science Foundation (PSF), Islamabad, Pakistan.
(16)Children's Hospital of Eastern Ontario Research Institute, University of
Ottawa, Ottawa, Canada.
(17)University Institute of Biochemistry and Biotechnology (UIBB), PMAS-Arid
Agriculture University, Rawalpindi, Pakistan.
(18)Neurochemicalbiology and Genetics Laboratory (NGL), Department of
Physiology, Faculty of Life Sciences, Government College University, Faisalabad,
Pakistan.
(19)Centre for Biotechnology and Microbiology, University of Swat, Swat,
Pakistan.
(20)Assistance Publique-Hôpitaux de Marseille, APHM, Hôpital Timone Enfants,
Service de Neurologie Pédiatrique, Marseille, France.
(21)T.Y. Nelson Department of Neurology and Neurosurgery, The Children's
Hospital at Westmead, Sydney, Australia.
(22)Specialty of Child and Adolescent Health and Discipline of Genomic Medicine,
The Children's Hospital at Westmead Clinical School, University of Sydney,
Sydney, Australia.
(23)Department of Clinical Genetics, The Children's Hospital at Westmead,
Sydney, Australia.
(24)National Institute for Health Research Oxford Biomedical Research Centre,
Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
(25)CENTOGENE GmbH, Rostock, Germany.
(26)Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing
Research Centre (THRC), Eberhard Karls University Tübingen, Tübingen, Germany.
(27)Department of Bioinformatics & Biotechnology, Faculty of Basic and Applied
Sciences, International Islamic University, Islamabad, Pakistan.
(28)Department of Pediatric Neurology, Children's Hospital and Institute of
Child Health, Lahore, Pakistan.
(29)Development and Behavioural Pediatrics Department, Institute of Child Health
and The Children Hospital, Lahore, Pakistan.
(30)Pediatric Neurology Department, Ghaem Hospital, Mashhad University of
Medical Sciences, Mashhad, Iran.
(31)Molecular and Clinical Sciences Institute, St. George's, University of
London, Cranmer Terrace, London, UK.
(32)Innovative Medical Research Center, Mashhad Branch, Islamic Azad University,
Mashhad, Iran.
(33)Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty
of Medicine, University Hospital Cologne, Cologne, Germany.
(34)Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to
Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen,
Germany.
(35)Department of Translational Genomics, Center for Genomic Medicine, King
Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
(36)Department of Anatomy and Cell Biology, College of Medicine, Alfaisal
University, Riyadh, Saudi Arabia.
(37)Cologne Center for Genomics (CCG), University of Cologne and University
Hospital Cologne, Cologne, Germany. [email protected].
(38)Institute of Biochemistry I, Medical Faculty, University of Cologne,
Cologne, Germany. [email protected].
(39)Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty
of Medicine, University Hospital Cologne, Cologne, Germany.
[email protected].
(40)Institute of Human Genetics, University Medical Center Göttingen, Göttingen,
Germany. [email protected].
(#)Contributed equally |
Is Sotrovimab effective for COVID-19? | Yes. Among high-risk patients with mild-to-moderate Covid-19, sotrovimab reduced the risk of disease progression. | BACKGROUND: Many recent studies have investigated the role of drug interventions
for coronavirus disease 2019 (COVID-19) infection. However, an important
question has been raised about how to select the effective and secure
medications for COVID-19 patients. The aim of this analysis was to assess the
efficacy and safety of the various medications available for severe and
non-severe COVID-19 patients based on randomized placebo-controlled trials
(RPCTs).
METHODS: We did an updated network meta-analysis. We searched the databases from
inception until July 31, 2021, with no language restrictions. We included RPCTs
comparing 49 medications and placebo in the treatment of severe and non-severe
patients (aged 18 years or older) with COVID-19 infection. We extracted data on
the trial and patient characteristics, and the following primary outcomes:
all-cause mortality, the ratios of virological cure, and treatment-emergent
adverse events. Odds ratio (OR) and their 95% confidence interval (CI) were used
as effect estimates.
RESULTS: From 3,869 publications, we included 61 articles related to 73 RPCTs
(57 in non-severe COVID-19 patients and 16 in severe COVID-19 patients),
comprising 20,680 patients. The mean sample size was 160 (interquartile range
96-393) in this study. The median duration of follow-up drugs intervention was
28 days (interquartile range 21-30). For increase in virological cure, we only
found that proxalutamide (OR 9.16, 95% CI 3.15-18.30), ivermectin (OR 6.33, 95%
CI 1.22-32.86), and low dosage bamlanivimab (OR 5.29, 95% CI 1.12-24.99) seemed
to be associated with non-severe COVID-19 patients when compared with placebo,
in which proxalutamide seemed to be better than low dosage bamlanivimab (OR
5.69, 95% CI 2.43-17.65). For decrease in all-cause mortality, we found that
proxalutamide (OR 0.13, 95% CI 0.09-0.19), imatinib (OR 0.49, 95% CI 0.25-0.96),
and baricitinib (OR 0.58, 95% CI 0.42-0.82) seemed to be associated with
non-severe COVID-19 patients; however, we only found that immunoglobulin gamma
(OR 0.27, 95% CI 0.08-0.89) was related to severe COVID-19 patients when
compared with placebo. For change in treatment-emergent adverse events, we only
found that sotrovimab (OR 0.21, 95% CI 0.13-0.34) was associated with non-severe
COVID-19 patients; however, we did not find any medications that presented a
statistical difference when compared with placebo among severe COVID-19
patients.
CONCLUSION: We conclude that marked variations exist in the efficacy and safety
of medications between severe and non-severe patients with COVID-19. It seems
that monoclonal antibodies (e.g., low dosage bamlanivimab, baricitinib,
imatinib, and sotrovimab) are a better choice for treating severe or non-severe
COVID-19 patients. Clinical decisions to use preferentially medications should
carefully consider the risk-benefit profile based on efficacy and safety of all
active interventions in patients with COVID-19 at different levels of infection. OBJECTIVE: To evaluate the efficacy and safety of antiviral antibody therapies
and blood products for the treatment of novel coronavirus disease 2019
(covid-19).
DESIGN: Living systematic review and network meta-analysis, with pairwise
meta-analysis for outcomes with insufficient data.
DATA SOURCES: WHO covid-19 database, a comprehensive multilingual source of
global covid-19 literature, and six Chinese databases (up to 21 July 2021).
STUDY SELECTION: Trials randomising people with suspected, probable, or
confirmed covid-19 to antiviral antibody therapies, blood products, or standard
care or placebo. Paired reviewers determined eligibility of trials independently
and in duplicate.
METHODS: After duplicate data abstraction, we performed random effects bayesian
meta-analysis, including network meta-analysis for outcomes with sufficient
data. We assessed risk of bias using a modification of the Cochrane risk of bias
2.0 tool. The certainty of the evidence was assessed using the grading of
recommendations assessment, development, and evaluation (GRADE) approach. We
meta-analysed interventions with ≥100 patients randomised or ≥20 events per
treatment arm.
RESULTS: As of 21 July 2021, we identified 47 trials evaluating convalescent
plasma (21 trials), intravenous immunoglobulin (IVIg) (5 trials), umbilical cord
mesenchymal stem cells (5 trials), bamlanivimab (4 trials),
casirivimab-imdevimab (4 trials), bamlanivimab-etesevimab (2 trials), control
plasma (2 trials), peripheral blood non-haematopoietic enriched stem cells (2
trials), sotrovimab (1 trial), anti-SARS-CoV-2 IVIg (1 trial), therapeutic
plasma exchange (1 trial), XAV-19 polyclonal antibody (1 trial), CT-P59
monoclonal antibody (1 trial) and INM005 polyclonal antibody (1 trial) for the
treatment of covid-19. Patients with non-severe disease randomised to antiviral
monoclonal antibodies had lower risk of hospitalisation than those who received
placebo: casirivimab-imdevimab (odds ratio (OR) 0.29 (95% CI 0.17 to 0.47); risk
difference (RD) -4.2%; moderate certainty), bamlanivimab (OR 0.24 (0.06 to
0.86); RD -4.1%; low certainty), bamlanivimab-etesevimab (OR 0.31 (0.11 to
0.81); RD -3.8%; low certainty), and sotrovimab (OR 0.17 (0.04 to 0.57); RD
-4.8%; low certainty). They did not have an important impact on any other
outcome. There was no notable difference between monoclonal antibodies. No other
intervention had any meaningful effect on any outcome in patients with
non-severe covid-19. No intervention, including antiviral antibodies, had an
important impact on any outcome in patients with severe or critical covid-19,
except casirivimab-imdevimab, which may reduce mortality in patients who are
seronegative.
CONCLUSION: In patients with non-severe covid-19, casirivimab-imdevimab probably
reduces hospitalisation; bamlanivimab-etesevimab, bamlanivimab, and sotrovimab
may reduce hospitalisation. Convalescent plasma, IVIg, and other antibody and
cellular interventions may not confer any meaningful benefit.
SYSTEMATIC REVIEW REGISTRATION: This review was not registered. The protocol
established a priori is included as a data supplement.
FUNDING: This study was supported by the Canadian Institutes of Health Research
(grant CIHR- IRSC:0579001321).
READERS' NOTE: This article is a living systematic review that will be updated
to reflect emerging evidence. Interim updates and additional study data will be
posted on our website (www.covid19lnma.com). The Food and Drug Administration has granted emergency use authorization to
sotrovimab for the treatment of mild to moderate COVID-19 in patients at
increased risk for progression to severe illness.Sotrovimab is a monoclonal
antibody that works directly against the spike protein of SARS-CoV-2 to block
its attachment and entry into a human cell. |
Is Otolin-1 a matrix protein? | Yes,
otolin-1 is a otoconia matrix protein. | In the biomineralization processes, proteins are thought to control the
polymorphism and morphology of the crystals by forming complexes of structural
and mineral-associated proteins. To identify such proteins, we have searched for
proteins that may form high-molecular-weight (HMW) aggregates in the matrix of
fish otoliths that have aragonite and vaterite as their crystal polymorphs. By
screening a cDNA library of the trout inner ear using an antiserum raised
against whole otolith matrix, a novel protein, named otolith matrix
macromolecule-64 (OMM-64), was identified. The protein was found to have a
molecular mass of 64 kDa, and to contain two tandem repeats and a Glu-rich
region. The structure of the protein and that of its DNA are similar to those of
starmaker, a protein involved in the polymorphism control in the zebrafish
otoliths [Söllner C, Burghammer M, Busch-Nentwich E, Berger J, Schwarz H, Riekel
C & Nicolson T (2003) Science302, 282-286]. (45)Ca overlay analysis revealed
that the Glu-rich region has calcium-binding activity. Combined analysis by
western blotting and deglycosylation suggested that OMM-64 is present in an HMW
aggregate with heparan sulfate chains. Histological observations revealed that
OMM-64 is expressed specifically in otolith matrix-producing cells and deposited
onto the otolith. Moreover, the HMW aggregate binds to the inner ear-specific
short-chain collagen otolin-1, and the resulting complex forms ring-like
structures in the otolith matrix. Overall, OMM-64, by forming a calcium-binding
aggregate that binds to otolin-1 and forming matrix protein architectures, may
be involved in the control of crystal morphology during otolith
biomineralization. BACKGROUND: The mammalian otoconial membrane is a dense extracellular matrix
containing bio-mineralized otoconia. This structure provides the mechanical
stimulus necessary for hair cells of the vestibular maculae to respond to linear
accelerations and gravity. In teleosts, Otolin is required for the proper
anchoring of otolith crystals to the sensory maculae. Otoconia detachment and
subsequent entrapment in the semicircular canals can result in benign paroxysmal
positional vertigo (BPPV), a common form of vertigo for which the molecular
basis is unknown. Several cDNAs encoding protein components of the mammalian
otoconia and otoconial membrane have recently been identified, and mutations in
these genes result in abnormal otoconia formation and balance deficits.
PRINCIPAL FINDINGS: Here we describe the cloning and characterization of
mammalian Otolin, a protein constituent of otoconia and the otoconial membrane.
Otolin is a secreted glycoprotein of ∼70 kDa, with a C-terminal globular domain
that is homologous to the immune complement C1q, and contains extensive
posttranslational modifications including hydroxylated prolines and glycosylated
lysines. Like all C1q/TNF family members, Otolin multimerizes into higher order
oligomeric complexes. The expression of otolin mRNA is restricted to the inner
ear, and immunohistochemical analysis identified Otolin protein in support cells
of the vestibular maculae and semi-circular canal cristae. Additionally, Otolin
forms protein complexes with Cerebellin-1 and Otoconin-90, two protein
constituents of the otoconia, when expressed in vitro. Otolin was also found in
subsets of support cells and non-sensory cells of the cochlea, suggesting that
Otolin is also a component of the tectorial membrane.
CONCLUSION: Given the importance of Otolin in lower organisms, the molecular
cloning and biochemical characterization of the mammalian Otolin protein may
lead to a better understanding of otoconial development and vestibular
dysfunction. OBJECTIVE: To test the hypothesis that age-related demineralization of otoconia
will result in an age-related increase in blood levels of otoconia matrix
protein, otolin-1.
STUDY DESIGN: Cross-sectional observational clinical trial.
SETTING: Clinical research center.
PATIENTS: Seventy nine men and women ranging in age from 22 to 95 years old.
INTERVENTIONS: Diagnostic.
MAIN OUTCOME MEASURES: Blood levels of otolin-1 in relation to age.
RESULTS: Levels of otolin-1 of subjects divided into four age groups (1: 20-30
[n = 20], 2: 50-65 [n = 20], 3: 66-80 [n = 20], 4: 81-95 [n = 19] years old)
demonstrated an increasing trend with age. The difference between otolin levels
of groups 2 and 3, as well as, (p = 0.04) and 2 and 4 (p = 0.031) were
statistically significant, but there was no significant difference between the
two oldest groups.
CONCLUSIONS: Otolin-1 blood levels are significantly higher in patients older
than 65 years of age. This is consistent with previous scanning electron
microscopy findings of age-related otoconia degeneration and increased
prevalence of benign paroxysmal positional vertigo (BPPV) with age. Normative
data provided here can serve as important reference values against which levels
from BPPV patients can be compared with further evaluate otolin-1 as a
circulatory biomarker for otoconia degeneration. |
List the drug targets of Faricimab? | Faricimab, a bispecific antibody that inhibits VEGF-A and Ang-2. | Introduction: The Tie-2/Angiopoietin pathway is a therapeutic target for the
treatment of neovascular age-related macular degeneration (nAMD) and diabetic
macular edema (DME). Activation of Tie-2 receptor via Ang-1 maintains vascular
stability to limit exudation. Ang-2, a competitive antagonist to Ang-1, and
VE-PTP, an endothelial-specific phosphatase, interfere with the Tie-2-Ang-1
axis, resulting in vascular leakage. Areas covered: Faricimab, a bispecific
antibody that inhibits VEGF-A and Ang-2, is in phase 3 trials for nAMD and DME.
Nesvacumab is an Ang-2 inhibitor; when coformulated with aflibercept, it failed
to show benefit over aflibercept monotherapy in achieving visual gains in phase
2 studies of nAMD and DME. ARP-1536 is an intravitreally administered VE-PTP
inhibitor undergoing preclinical studies. AKB-9778 is a subcutaneously
administered VE-PTP inhibitor that, when combined with monthly ranibizumab,
reduced DME more effectively than ranibizumab monotherapy in a phase 2 study.
AKB-9778 monotherapy did not reduce diabetic retinopathy severity score compared
to placebo. AXT107, currently in the preclinical phase, promotes conversion of
Ang-2 into a Tie-2 agonist and blocks signaling through VEGFR2 and other
receptor tyrosine-kinases. Expert opinion: Tie-2/Angiopoietin pathway modulators
show promise to reduce treatment burden and improve visual outcomes in nAMD and
DME, with potential to treat cases refractory to current treatment modalities. This review summarizes the latest findings in the literature of Angiopoietin-2
(Ang-2), Tyrosine-protein kinase receptor (Tie-2) complex, and faricimab along
with their involvement for the treatment of retinal vascular diseases in various
clinical trials. In ischemic diseases, such as diabetic retinopathy, Ang-2 is
upregulated, deactivating Tie-2, resulting in vascular leakage, pericyte loss,
and inflammation. Recombit Angiopeotin-1 (Ang-1), Ang-2-blocking molecules,
and inhibitors of vascular endothelial protein tyrosine phosphatase (VE-PTP)
decrease inflammation-associated vascular leakage, showing therapeutic effects
in diabetes, atherosclerosis, and ocular neovascular diseases. In addition,
novel studies show that angiopoietin-like proteins may play an important role in
cellular metabolism leading to retinal vascular diseases. Current therapeutic
focus combines Ang-Tie targeted drugs with other anti-angiogenic or immune
therapies. Clinical studies have identified faricimab, a novel bispecific
antibody designed for intravitreal use, to simultaneously bind and neutralize
Ang-2 and VEGF-A for treatment of diabetic eye disease. By targeting both Ang-2
and vascular endothelial growth factor-A (VEGF-A), faricimab displays an
improved and sustained efficacy over longer treatment intervals, delivering
superior vision outcomes for patients with diabetic macular edema and reducing
the treatment burden for patients with neovascular age-related macular
degeneration and diabetic macular edema. Phase 2 results have produced promising
outcomes with regard to efficacy and durability. Faricimab is currently being
evaluated in global Phase 3 studies. INTRODUCTION: Intravitreal antivascular endothelial growth factor (VEGF) drugs
represent the first-line treatment option for wet age-related macular
degeneration (w-AMD) and diabetic macular edema (DME); however, the frequent
injection intervals have illuminated to the necessity for new molecules allowing
a more prolonged treatment regimen. Faricimab is a promising bispecific drug
targeting VEGF-A and the Ang-Tie/pathway. Phase II STAIRWAY and AVENUE Trials
showed its clinical efficacy for the treatment of w-AMD, while the phase II
BOULEVARD Trial revealed its superiority to monthly ranibizumab in the
management of DME with a monthly treatment regimen. The agents are awaiting
approval for the treatment of w-AMD and DME.
AREAS COVERED: This article presents an overview of w-AMD and diabetic
retinopathy and examines the progress of Faricimab through clinical trials. It
offers insights on where Faricimab may be placed in the future market of
anti-VEGF treatments and discusses the role of Ang/Tie pathway as a potential
additive weapon for the treatment of w-AMD, DME, and retinal vein occlusion
(RVO).
EXPERT OPINION: The possibility of administering faricimab with more prolonged
treatment intervals represents an important advantage to decrease the treatment
burden and improve patient compliance. Further phase III trials should provide
more evidence on clinical efficacy. Conflict of interest statement: AK: Consultant: Adverum, Aerpio, Allergan,
Chengdu Kanghong, DORC, Genentech, Inc., Kato, Kodiak, Novartis, Gemini,
Graybug, Gyroscope, Opthea, Oxurion, PolyPhotonix, Recens Medical, Regenxbio,
Roche Research support: Adverum, Alkahest, Allegro, Allergan, Chengdu Kanghong,
Gemini, Genentech, Inc., Gyroscope, Iveric Bio, NGM, Neurotech, Kodiak,
Novartis, Opthea, Oxurion, Regenxbio, Recens Medical, Roche Lecture fees:
Allergan, Genentech, Novartis CD: Consultant: Genentech, Roche, Regeneron,
Novartis, IvericBio Research support: Genentech, Roche, Regeneron, Novartis,
IvericBio, Kodiak, Adverum, Gyroscope Lecture fees: Novartis, DORC CYW:
Consultant: Allergan/AbbVie, Alcon, Alimera Sciences, Novartis, Regeneron,
REGENXBIO, Genentech, DORC DE: Consultant: Genentech, Regeneron, Allergan,
Novartis, Notal Vision, EyePoint, Gyroscope, Kodiak, RecensMedical, DORC,
IvericBio, Apellis, KKR, Regenxbio, Bausch & Lomb Research support: AsclepiX,
Genentech, Bayer, Novartis, Alimera, Opthea, Ocular Therapeutix, EyePoint,
Mylan, Chengdu, Gemini, Gyroscope, Kodiak, NGM, RecensMedical, Alkahest, Ionis,
IvericBio, Regenxbio Lecture fees: Genentech, Bayer, Allergan, Novartis,
EyePoint, DORC, Apellis Equity/Stockholder: Clearside, US Retina, Hemera
Biopharmaceuticals, Boston Image Reading Center, Network Eye Founder: Network
Eye RPS: Consultant: Regeneron, Genentech, Alcon, Novartis, Asclepix, Gyroscope,
Bausch and Lomb. Research support: Apellis, NGM Biopharma The authors report no
other conflicts of interest in this work. |
What induces downstream of gene (DoG) readthrough transcription? | Stress-induced transcriptional readthrough generates very long downstream of gene containing transcripts (DoGs), which may explain up to 20% of intergenic transcription. Massive induction of transcriptional readthrough generates downstream of gene-containing transcripts (DoGs) in cells under stress condition. Ca2+ signaling mediates reduced transcription termination in response to certain stress conditions. This reduction allows readthrough transcription, generating a highly inducible and diverse class of downstream of gene containing transcripts (DoGs) that we have recently described. | In cells productively infected with adenovirus type 5, transcription is not
terminated between the E1a gene and the adjacent downstream E1b gene. Insertion
of the mouse beta(maj)-globin transcription termination sequence (GGT) into the
E1a coding region dramatically reduces early, but not late, E1b expression (E.
Falck-Pedersen, J. Logan, T. Shenk, and J. E. Darnell, Jr., Cell 40:897-905,
1985). In the study described herein, we showed that base substitution mutations
in the globin DNA that specifically relieved transcription termination also
restored early E1b promoter activity in cis, establishing that maximal early E1b
expression requires readthrough transcription originating from the adjacent
upstream gene. To identify potential targets of readthrough activation, a series
of recombit viruses with double mutations was constructed. Each double-mutant
virus strain had the transcription termination sequences in the first exon of
E1a and a deletion within the transcription control region of E1b. Early E1b
expression from the double-mutant strains was more defective than that from
strains containing either mutation alone, indicating that the deleted regions
(positions -362 to -35) are not the target for readthrough activation. Two
findings suggested that a cis-domit property of early viral templates is
important for readthrough activation. First, the early E1b defect caused by the
GGT insertion was not complemented in trans by factors present in late-infected
cells. Second, restoration of E1b transcription at late times occurred
concurrently with viral DNA replication. Readthrough activation may help convert
virion DNA into a transcriptionally competent template prior to DNA replication
and late transcription. The calcium ion (Ca2+) is a key intracellular signaling molecule with
far-reaching effects on many cellular processes. One of the most important such
Ca2+ regulated processes is transcription. A body of literature describes the
effect of Ca2+ signaling on transcription initiation as occurring mainly through
activation of gene-specific transcription factors by Ca2+-induced signaling
cascades. However, the reach of Ca2+ extends far beyond the first step of
transcription. In fact, Ca2+ can regulate all phases of transcription, with
additional effects on transcription-associated events such as alternative
splicing. Importantly, Ca2+ signaling mediates reduced transcription termination
in response to certain stress conditions. This reduction allows readthrough
transcription, generating a highly inducible and diverse class of downstream of
gene containing transcripts (DoGs) that we have recently described. Previous studies demonstrated that massive induction of transcriptional
readthrough generates downstream of gene-containing transcripts (DoGs) in cells
under stress condition. Here, we analyzed TSS-seq (transcription start site
sequencing) data from the DBTSS database. We investigated TSS tags at the end of
gene for all pan-stress and untreated-cell DoGs, in comparison with
expression-matched non-DoGs. We observed significantly more TSS tags at the end
of pan-stress and untreated-cell DoG genes than non-DoG genes, even though their
TSS tags in the promoter is the same. Importantly, the median value of TSS tags
at gene end normalized to gene promoter is significantly higher than the median
expression ratio of short DoG to host gene and of long DoG to host gene. Our
results indicate that downstream overlapping long non-coding RNAs derived from
the TSS at the gene end may be an important source of DoGs. Naturally occurring stress-induced transcriptional readthrough is a recently
discovered phenomenon, in which stress conditions lead to dramatic induction of
long transcripts as a result of transcription termination failure. In 2015, we
reported the induction of such downstream of gene (DoG) containing transcripts
upon osmotic stress in human cells, while others observed similar transcripts in
virus-infected and cancer cells. Using the rigorous methodology Cap-Seq, we
demonstrated that DoGs result from transcriptional readthrough, not de novo
initiation. More recently, we presented a genome-wide comparison of NIH3T3 mouse
cells subjected to osmotic, heat, and oxidative stress and concluded that
massive induction of transcriptional readthrough is a hallmark of the mammalian
stress response. In their recent letter, Huang and Liu in contrast claim that
DoG transcripts result from novel transcription initiation near the ends of
genes. Their conclusions rest on analyses of a publicly available transcription
start site (TSS-Seq) dataset from unstressed NIH3T3 cells. Here, we present
evidence that this dataset identifies not only true transcription start
sites, TSSs, but also 5'-ends of numerous snoRNAs, which are generally processed
from introns in mammalian cells. We show that failure to recognize these
erroneous assignments in the TSS-Seq dataset, as well as ignoring published
Cap-Seq data on TSS mapping during osmotic stress, have led to misinterpretation
by Huang and Liu. We conclude that, contrary to the claims made by Huang and
Liu, TSS-Seq reads near gene ends cannot explain the existence of DoGs, nor
their stress-mediated induction. Rather it is, as we originally demonstrated,
transcriptional readthrough that leads to the formation of DoGs. BACKGROUND: Recent studies have described a widespread induction of
transcriptional readthrough as a consequence of various stress conditions in
mammalian cells. This novel phenomenon, initially identified from analysis of
RNA-seq data, suggests intriguing new levels of gene expression regulation.
However, the mechanism underlying naturally occurring transcriptional
readthrough, as well as its regulatory consequences, still remain elusive.
Furthermore, the readthrough response to stress has thus far not been
investigated outside of mammalian species, and the occurrence of readthrough in
many physiological and disease conditions remains to be explored.
RESULTS: To facilitate a wider investigation into transcriptional readthrough,
we created the DoGFinder software package, for the streamlined identification
and quantification of readthrough transcripts, also known as DoGs (Downstream of
Gene-containing transcripts), from any RNA-seq dataset. Using DoGFinder, we
explore the dependence of DoG discovery potential on RNA-seq library depth, and
show that stress-induced readthrough induction discovery is robust to sequencing
depth, and input parameter settings. We further demonstrate the use of the
DoGFinder software package on a new publically available RNA-seq dataset, and
discover DoG induction in human PME cells following hypoxia - a previously
unknown readthrough inducing stress type.
CONCLUSIONS: DoGFinder will enable users to explore, in a few simple steps, the
readthrough phenomenon in any condition and organism. DoGFinder is freely
available at https://github.com/shalgilab/DoGFinder . |
What is the effect of rHDL-apoE3 on endothelial cell migration? | rHDL-apoE3 has been shown to promote endothelial cell migration. | INTRODUCTION: Atherosclerotic Coronary Artery Disease (ASCAD) is the leading
cause of mortality worldwide. Novel therapeutic approaches aiming to improve the
atheroprotective functions of High Density Lipoprotein (HDL) include the use of
reconstituted HDL forms containing human apolipoprotein A-I (rHDL-apoA-I). Given
the strong atheroprotective properties of apolipoprotein E3 (apoE3), rHDL-apoE3
may represent an attractive yet largely unexplored therapeutic agent.
OBJECTIVE: To evaluate the atheroprotective potential of rHDL-apoE3 starting
with the unbiased assessment of global transcriptome effects and focusing on
endothelial cell (EC) migration as a critical process in re-endothelialization
and atherosclerosis prevention. The cellular, molecular and functional effects
of rHDL-apoE3 on EC migration-associated pathways were assessed, as well as the
potential translatability of these findings in vivo.
METHODS: Human Aortic ECs (HAEC) were treated with rHDL-apoE3 and total RNA was
analyzed by whole genome microarrays. Expression and phosphorylation changes of
key EC migration-associated molecules were validated by qRT-PCR and Western blot
analysis in primary HAEC, Human Coronary Artery ECs (HCAEC) and the human
EA.hy926 EC line. The capacity of rHDL-apoE3 to stimulate EC migration was
assessed by wound healing and transwell migration assays. The contribution of
MEK1/2, PI3K and the transcription factor ID1 in rHDL-apoE3-induced EC migration
and activation of EC migration-related effectors was assessed using specific
inhibitors (PD98059: MEK1/2, LY294002: PI3K) and siRNA-mediated gene silencing,
respectively. The capacity of rHDL-apoE3 to improve vascular permeability and
hypercholesterolemia in vivo was tested in a mouse model of hypercholesterolemia
(apoE KO mice) using Evans Blue assays and lipid/lipoprotein analysis in the
serum, respectively.
RESULTS: rHDL-apoE3 induced significant expression changes in 198 genes of HAEC
mainly involved in re-endothelialization and atherosclerosis-associated
functions. The most pronounced effect was observed for EC migration, with 42/198
genes being involved in the following EC migration-related pathways: 1) MEK/ERK,
2) PI3K/AKT/eNOS-MMP2/9, 3) RHO-GTPases, 4) integrin. rHDL-apoE3 induced changes
in 24 representative transcripts of these pathways in HAEC, increasing the
expression of their key proteins PIK3CG, EFNB2, ID1 and FLT1 in HCAEC and
EA.hy926 cells. In addition, rHDL-apoE3 stimulated migration of HCAEC and
EA.hy926 cells, and the migration was markedly attenuated in the presence of
PD98059 or LY294002. rHDL-apoE3 also increased the phosphorylation of ERK1/2,
AKT, eNOS and p38 MAPK in these cells, while PD98059 and LY294002 inhibited
rHDL-apoE3-induced phosphorylation of ERK1/2, AKT and p38 MAPK, respectively. LY
had no effect on rHDL-apoE3-mediated eNOS phosphorylation. ID1 siRNA markedly
decreased EA.hy926 cell migration by inhibiting rHDL-apoE3-triggered ERK1/2 and
AKT phosphorylation. Finally, administration of a single dose of rHDL-apoE3 in
apoE KO mice markedly improved vascular permeability as demonstrated by the
reduced concentration of Evans Blue dye in tissues such as the stomach, the
tongue and the urinary bladder and ameliorated hypercholesterolemia.
CONCLUSIONS: rHDL-apoE3 significantly enhanced EC migration in vitro,
predomitly via overexpression of ID1 and subsequent activation of MEK1/2 and
PI3K, and their downstream targets ERK1/2, AKT and p38 MAPK, respectively, and
improved vascular permeability in vivo. These novel insights into the rHDL-apoE3
functions suggest a potential clinical use to promote re-endothelialization and
retard development of atherosclerosis. |
Is AGO2 related to cytokinesis? | Yes. AGO2 localizes to cytokinetic protrusions in a p38-dependent manner and is needed for accurate cell division. | Argonaute 2 (AGO2) is an indispensable component of the RNA-induced silencing
complex, operating at the translational or posttranscriptional level. It is
compartmentalized into structures such as GW- and P-bodies, stress granules and
adherens junctions as well as the midbody. Here we show using
immunofluorescence, image and bioinformatic analysis and cytogenetics that AGO2
also resides in membrane protrusions such as open- and close-ended tubes. The
latter are cytokinetic bridges where AGO2 colocalizes at the midbody arms with
cytoskeletal components such as α-Τubulin and Aurora B, and various kinases.
AGO2, phosphorylated on serine 387, is located together with Dicer at the
midbody ring in a manner dependent on p38 MAPK activity. We further show that
AGO2 is stress sensitive and important to ensure the proper chromosome
segregation and cytokinetic fidelity. We suggest that AGO2 is part of a
regulatory mechanism triggered by cytokinetic stress to generate the appropriate
micro-environment for local transcript homeostasis. |
Hampton’s hump is characteristic to which disease? | Hampton’s hump is characteristic to pulmonary embolism. | A 56-year-old man presented to the Accident and Emergency Department with
pleuritic chest pain of sudden onset. He gave a history of short-distance air
travel ten days earlier. Chest radiograph showed a peripheral-based opacity in
the right lower zone, which was not seen in a previous study done three months
ago, suggestive of Hampton's hump. The D-dimer level was raised. Computed
tomography pulmonary angiography confirmed the diagnosis of pulmonary embolism
in a right lower lobe segmental branch, with adjacent collapsed lung, consistent
with lung infarction. The patient was started on heparin injection with
significant relief of his symptoms. The clinical and imaging features of
pulmonary embolism are described, with emphasis on the historical radiographic
signs and the current dual-energy computed tomography innovations. We discuss a case of a 20-year-old woman presenting with chest pain found to
have a Hampton's hump on chest x-ray and corresponding wedge infarct on computed
tomographic scan. Contrary to our suspicion that this febrile and tachycardic
patient had a pulmonary embolism, she was later determined to have a septic
embolus secondary to endocarditis. We highlight the difficulties in diagnosing
certain cases of endocarditis in the emergency department, as well as the
difficulties in distinguishing septic emboli from pulmonary emboli,especially
with plain radiographs. |
What is the activity of Indoleamine 2,3-dioxygenase 1. | Indoleamine 2,3-dioxygenase 1 (IDO1), a known immunosuppressive enzyme that catalyzes the rate-limiting step in the oxidation of tryptophan (Trp) to kynurenine (Kyn), has received increasing attention as an attractive immunotherapeutic target for cancer therapy. | Author information:
(1)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected].
(2)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected].
(3)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected].
(4)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected].
(5)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected].
(6)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected].
(7)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected].
(8)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected].
(9)Shanghai Key Lab of Chemical Assessment and Sustainability, School of
Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai,
200092, China. Electronic address: [email protected].
(10)Department of Pharmacology, School of Pharmacy, Fudan University, Zhangheng
Road 826, Shanghai, 201203, China. Electronic address: [email protected].
(11)State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan
University, Songhu Road 2005, Shanghai, 200438, China. Electronic address:
[email protected]. The contribution of the bone marrow (BM) immune microenvironment to acute
myeloid leukemia (AML) development is well-known, but its prognostic
significance is still elusive. Indoleamine 2,3-dioxygenase 1 (IDO1), which is
negatively regulated by the BIN1 proto-oncogene, is an interferon-γ-inducible
mediator of immune tolerance. With the aim to develop a prognostic IDO1-based
immune gene signature, biological and clinical data of 982 patients with newly
diagnosed, nonpromyelocytic AML were retrieved from public datasets and analyzed
using established computational pipelines. Targeted transcriptomic profiles of
24 diagnostic BM samples were analyzed using the NanoString's nCounter platform.
BIN1 and IDO1 were inversely correlated and individually predicted overall
survival. PLXNC1, a semaphorin receptor involved in inflammation and immune
response, was the IDO1-interacting gene retaining the strongest prognostic
value. The incorporation of PLXNC1 into the 2-gene IDO1-BIN1 score gave rise to
a powerful immune gene signature predicting survival, especially in patients
receiving chemotherapy. The top differentially expressed genes between
IDO1lowand IDO-1high and between PLXNC1lowand PLXNC1high cases further improved
the prognostic value of IDO1 providing a 7- and 10-gene immune signature, highly
predictive of survival and correlating with AML mutational status at diagnosis.
Taken together, our data indicate that IDO1 is pivotal for the construction of
an immune gene signature predictive of survival in AML patients. Given the
emerging role of immunotherapies for AML, our findings support the incorporation
of immune biomarkers into current AML classification and prognostication
algorithms. Immune escape is an early phenomenon in cancer development/progression.
Indoleamine 2,3-dioxygenase 1 (IDO1) is a normal endogenous mechanism of
acquired peripheral immune tolerance and may therefore be tumor-promoting. This
study investigated the clinical relevance of IDO1 expression by immune cells in
the lymph nodes and blood and of the serum kynurenine/tryptophan (Kyn/Trp) ratio
in 65 systemic treatment naïve stage I-III melanoma patients. Blood samples were
collected within the first year of diagnosis. Patients had a median follow-up of
61 months. High basal IDO1 expression in peripheral monocytes and low
IFNγ-induced IDO1 upregulation correlated with worse outcome independent from
disease stage. Interestingly studied factors were not interrelated. During
follow-up, the risk of relapse was 9% (2/22) in the subgroup with high
IFNγ-induced IDO1 upregulation in monocytes. In contrast, if IDO1 upregulation
was low, relapse occurred in 30% (3/10) of patients with low basal IDO1
expression in monocytes and in 61.5% (8/13) in the subgroup with high basal IDO1
expression in monocytes (Log-Rank test, p=0.008). This study reveals some immune
features in the blood of early stage melanoma that may be of relevance for
disease outcome. These may offer a target for sub-stratification and early
intervention. Indoleamine 2,3-dioxygenase 1 (IDO1), a known immunosuppressive enzyme that
catalyzes the rate-limiting step in the oxidation of tryptophan (Trp) to
kynurenine (Kyn), has received increasing attention as an attractive
immunotherapeutic target for cancer therapy. Up to now, eleven small-molecule
IDO1 inhibitors have entered clinical trials for the treatment of cancers. In
addition, proteolysis targeting chimera (PROTAC) based degraders also provide
prospects for cancer therapy. Herein we present a comprehensive overview of the
medicinal chemistry strategies and potential therapeutic applications of IDO1
inhibitors in nonclinical trials and IDO1-PROTAC degraders. |
What is the purpose of Macropinocytosis? | Macropinocytosis is an endocytic process, which involves the engulfment of extra-cellular content in vesicles known as macropinosomes. | Gonococcal entry into primary human urethral epithelial cells (HUEC) can occur
by macropinocytosis. Scanning and transmission electron microscopy revealed
lamellipodia surrounding gonococci, and confocal laser scanning microscopy
analysis showed organisms colocalized with M(r) 70,000 fluorescein
isothiocyanate-labeled dextran within the cells. Phosphoinositide 3-kinase
inhibitors and an actin polymerization inhibitor prevented macropinocytic entry
of gonococci into HUEC. Macropinocytosis results from the closure of lamellipodia generated by membrane
ruffling, thereby reflecting cortical actin dynamics. Both transformation of
Rat-1 fibroblasts by v-Src or K-Ras and stable transfection for expression of
domit-positive, wild-type phosphoinositide 3-kinase (PI3K) regulatory subunit
p85 alpha constitutively led to stress fiber disruption, cortical actin
recruitment, extensive ruffling, and macropinosome formation, as measured by a
selective acceleration of fluid-phase endocytosis. These alterations closely
correlated with activation of PI3K and phosphatidylinositol-specific
phospholipase C (PI-PLC), as assayed by 3-phosphoinositide synthesis in situ and
in vitro and inositol 1, 4,5 trisphosphate steady-state levels, respectively;
they were abolished by stable transfection of v-Src-transformed cells for
domit-negative truncated p85 alpha expression and by pharmacological
inhibitors of PI3K and PI-PLC, indicating a requirement for both enzymes.
Whereas PI3K activation resisted PI-PLC inhibition, PI-PLC activation was
abolished by a PI3K inhibitor and domit-negative transfection, thus placing
PI-PLC downstream of PI3K. Together, these data suggest that permanent
sequential activation of both PI3K and PI-PLC is necessary for the dramatic
reorganization of the actin cytoskeleton in oncogene-transformed fibroblasts,
resulting in constitutive ruffling and macropinocytosis. Macropinocytosis is a form of endocytosis that accompanies cell surface
ruffling. It is distinct in many ways from the better characterized
micropinocytosis, which includes clathrin-coated vesicle endocytosis and small
uncoated vesicles. Because macropinosomes are relatively large, they provide an
efficient route for non-selective endocytosis of solute macromolecules. This
route may facilitate MHC-class-II-restricted antigen presentation by dendritic
cells. Because the ruffling that leads to macropinocytosis is regulated, it has
been exploited by some pathogenic bacteria as a novel route for entry into
cells. Previously, we reported that fluid-phase endocytosis of native LDL by
PMA-activated human monocytederived macrophages converted these macrophages into
cholesterol-enriched foam cells (Kruth, H. S., Huang, W., Ishii, I., and Zhang,
W. Y. (2002) J. Biol. Chem. 277, 34573-34580). Uptake of fluid by cells can
occur either by micropinocytosis within vesicles (<0.1 microm diameter) or by
macropinocytosis within vacuoles ( approximately 0.5-5.0 microm) named
macropinosomes. The current investigation has identified macropinocytosis as the
pathway for fluid-phase LDL endocytosis and determined signaling and
cytoskeletal components involved in this LDL endocytosis. The
phosphatidylinositol 3-kinase inhibitor, LY294002, which inhibits
macropinocytosis but does not inhibit micropinocytosis, completely blocked
PMA-activated macrophage uptake of fluid and LDL. Also, nystatin and filipin,
inhibitors of micropinocytosis from lipid-raft plasma membrane domains, both
failed to inhibit PMA-stimulated macrophage cholesterol accumulation. Time-lapse
video phase-contrast microscopy and time-lapse digital confocal-fluorescence
microscopy with fluorescent DiI-LDL showed that PMA-activated macrophages took
up LDL in the fluid phase by macropinocytosis. Macropinocytosis of LDL depended
on Rho GTPase signaling, actin, and microtubules. Bafilomycin A1, the vacuolar
H+-ATPase inhibitor, inhibited degradation of LDL and caused accumulation of
undegraded LDL within macropinosomes and multivesicular body endosomes. LDL in
multivesicular body endosomes was concentrated >40-fold over its concentration
in the culture medium consistent with macropinosome shrinkage by maturation into
multivesicular body endosomes. Macropinocytosis of LDL taken up in the fluid
phase without receptor-mediated binding of LDL is a novel endocytic pathway that
generates macrophage foam cells. Macropinocytosis in macrophages and possibly
other vascular cells is a new pathway to target for modulating foam cell
formation in atherosclerosis. Macropinocytosis defines a series of events initiated by extensive plasma
membrane reorganization or ruffling to form an external macropinocytic structure
that is then enclosed and internalized. The process is constitutive in some
organisms and cell types but in others it is only pronounced after growth factor
stimulation. Internalized macropinosomes share many features with phagosomes and
both are distinguished from other forms of pinocytic vesicles by their large
size, morphological heterogeneity and lack of coat structures. A paucity of
information is available on other distinguishing features for macropinocytosis
such as specific marker proteins and drugs that interfere with its mechanism
over other endocytic processes. This has hampered efforts to characterize the
dynamics of this pathway and to identify regulatory proteins that are expressed
in order to allow it to proceed. Upon internalization, macropinosomes acquire
regulatory proteins common to other endocytic pathways, suggesting that their
identities as unique structures are short-lived. There is however less consensus
regarding the overall fate of the macropinosome cargo or its limiting membrane
and processes such as fusion, tubulation, recycling and regulated exocytosis
have all been implicated in shaping the macropinosome and directing cargo
traffic. Macropinocytosis has also been implicated in the internalization of
cell penetrating peptides that are of significant interest to researchers aiming
to utilize their translocation abilities to deliver therapeutic entities such as
genes and proteins into cells. This review focuses on recent findings on the
regulation of macropinocytosis, the intracellular fate of the macropinosome and
discusses evidence for the role of this pathway as a mechanism of entry for cell
penetrating peptides. Macropinocytosis is exploited by many pathogens for entry into cells.
Coronaviruses (CoVs) such as severe acute respiratory syndrome (SARS) CoV and
Middle East respiratory syndrome CoV are important human pathogens; however,
macropinocytosis during CoV infection has not been investigated. We demonstrate
that the CoVs SARS CoV and murine hepatitis virus (MHV) induce macropinocytosis,
which occurs late during infection, is continuous, and is not associated with
virus entry. MHV-induced macropinocytosis results in vesicle internalization, as
well as extended filopodia capable of fusing with distant cells. MHV-induced
macropinocytosis requires fusogenic spike protein on the cell surface and is
dependent on epidermal growth factor receptor activation. Inhibition of
macropinocytosis reduces supernatant viral titers and syncytia but not
intracellular virus titers. These results indicate that macropinocytosis likely
facilitates CoV infection through enhanced cell-to-cell spreading. Our studies
are the first to demonstrate virus use of macropinocytosis for a role other than
entry and suggest a much broader potential exploitation of macropinocytosis in
virus replication and host interactions. Importance: Coronaviruses (CoVs),
including severe acute respiratory syndrome (SARS) CoV and Middle East
respiratory syndrome CoV, are critical emerging human pathogens.
Macropinocytosis is induced by many pathogens to enter host cells, but other
functions for macropinocytosis in virus replication are unknown. In this work,
we show that CoVs induce a macropinocytosis late in infection that is
continuous, independent from cell entry, and associated with increased virus
titers and cell fusion. Murine hepatitis virus macropinocytosis requires a
fusogenic virus spike protein and signals through the epidermal growth factor
receptor and the classical macropinocytosis pathway. These studies demonstrate
CoV induction of macropinocytosis for a purpose other than entry and indicate
that viruses likely exploit macropinocytosis at multiple steps in replication
and pathogenesis. Macropinocytosis is a means by which eukaryotic cells ingest extracellular
liquid and dissolved molecules. It is widely conserved amongst cells that can
take on amoeboid form and, therefore, appears to be an ancient feature that can
be traced back to an early stage of evolution. Recent advances have highlighted
how this endocytic process can be subverted during pathology - certain cancer
cells use macropinocytosis to feed on extracellular protein, and many viruses
and bacteria use it to enter host cells. Prion and prion-like proteins can also
spread and propagate from cell to cell through macropinocytosis. Progress is
being made towards using macropinocytosis therapeutically, either to deliver
drugs to or cause cell death by inducing catastrophically rapid fluid uptake.
Mechanistically, the Ras signalling pathway plays a prominent and conserved
activating role in amoebae and in mammals; mutant amoebae with abnormally high
Ras activity resemble tumour cells in their increased capacity for growth using
nutrients ingested through macropinocytosis. This Commentary takes a functional
and evolutionary perspective to highlight progress in understanding and use of
macropinocytosis, which is an ancient feeding process used by single-celled
phagotrophs that has now been put to varied uses by metazoan cells and is abused
in disease states, including infection and cancer. Macropinocytosis has received increasing attention in recent years for its
various roles in nutrient acquisition, immune surveillance, and virus and cancer
pathologies. In most cases macropinocytosis is initiated by the sudden increase
in an external stimulus such as a growth factor. This "induced" form of
macropinocytosis has been the subject of much of the work addressing its
mechanism and function over the years. An alternative, "constitutive" form of
macropinocytosis restricted to primary innate immune cells also exists, although
its mechanism has remained severely understudied. This mini-review focuses on
the very recent advances that have shed new light on the initiation, formation
and functional relevance of constitutive macropinocytosis in primary innate
immune cells. An emphasis is placed on how this new understanding of
constitutive macropinocytosis is helping to define the sentinel function of
innate immune cells including polarized macrophages and dendritic cells. Macropinocytosis is an actin-driven process of large-scale and non-specific
fluid uptake used for feeding by some cancer cells and the macropinocytosis
model organism Dictyostelium discoideum In Dictyostelium, macropinocytic cups
are organized by 'macropinocytic patches' in the plasma membrane. These contain
activated Ras, Rac and phospholipid PIP3, and direct actin polymerization to
their periphery. We show that a Dictyostelium Akt (PkbA) and an SGK (PkbR1)
protein kinase act downstream of PIP3 and, together, are nearly essential for
fluid uptake. This pathway enables the formation of larger macropinocytic
patches and macropinosomes, thereby dramatically increasing fluid uptake.
Through phosphoproteomics, we identify a RhoGAP, GacG, as a PkbA and PkbR1
target, and show that it is required for efficient macropinocytosis and
expansion of macropinocytic patches. The function of Akt and SGK in cell feeding
through control of macropinosome size has implications for cancer cell biology. Macropinocytosis has emerged as an important nutrient supply pathway that
sustains cell growth of cancer cells within the nutrient-poor tumor
microenvironment. By internalizing extracellular fluid through this bulk
endocytic pathway, albumin is supplied to the cancer cells, which, after
degradation, serves as an amino acid source to meet the high nutrient demands of
these highly proliferating cells. Here, we describe a streamlined protocol for
visualization and quantitation of macropinosomes in adherent cancer cells grown
in vitro. The determination of the "macropinocytic index" provides a tool for
measuring the extent to which this internalization pathway is utilized within
the cancer cells and allows for comparison between different cell lines and
treatments. The protocol provided herein has been optimized for reproducibility
and is readily adaptable to multiple conditions and settings. Macropinocytosis is a prevalent and essential pathway in macrophages where it
contributes to anti-microbial responses and innate immune cell functions. Cell
surface ruffles give rise to phagosomes and to macropinosomes as
multi-functional compartments that contribute to environmental sampling,
pathogen entry, plasma membrane turnover and receptor signalling. Rapid, high
resolution, lattice light sheet imaging demonstrates the dynamic nature of
macrophage ruffling. Pathogen-mediated activation of surface and endosomal
Toll-like receptors (TLRs) in macrophages upregulates macropinocytosis. Here,
using multiple forms of imaging and microscopy, we track membrane-associated,
fluorescently-tagged Rab8a expressed in live macrophages, using a variety of
cell markers to demonstrate Rab8a localization and its enrichment on early
macropinosomes. Production of a novel biosensor and its use for quantitative
FRET analysis in live cells, pinpoints macropinosomes as the site for
TLR-induced activation of Rab8a. We have previously shown that TLR signalling,
cytokine outputs and macrophage programming are regulated by the GTPase Rab8a
with PI3 Kγ as its effector. Finally, we highlight another effector, the
phosphatase OCRL, which is located on macropinosomes and interacts with Rab8a,
suggesting that Rab8a may operate on multiple levels to modulate
phosphoinositides in macropinosomes. These findings extend our understanding of
macropinosomes as regulatory compartments for innate immune function in
macrophages. This article is part of the Theo Murphy meeting issue
'Macropinocytosis'. In tumour cells, macropinocytosis functions as an amino acid supply route and
supports cancer cell survival and proliferation. Initially demonstrated in
oncogenic KRAS-driven models of pancreatic cancer, macropinocytosis triggers the
internalization of extracellular proteins via discrete endocytic vesicles called
macropinosomes. The incoming protein cargo is targeted for lysosome-dependent
degradation, causing the intracellular release of amino acids. These
protein-derived amino acids support metabolic fitness by contributing to the
intracellular amino acid pools, as well as to the biosynthesis of central carbon
metabolites. In this way, macropinocytosis represents a novel amino acid supply
route that tumour cells use to survive the nutrient-poor conditions of the
tumour microenvironment. Macropinocytosis has also emerged as an entry mechanism
for a variety of omedicines, suggesting that macropinocytosis regulation in
the tumour setting can be harnessed for the delivery of anti-cancer
therapeutics. A slew of recent studies point to the possibility that
macropinocytosis is a pervasive feature of many different tumour types. In this
review, we focus on the role of this important uptake mechanism in a variety of
cancers and highlight the main molecular drivers of macropinocytosis in these
maligcies. This article is part of the Theo Murphy meeting issue
'Macropinocytosis'. Macropinosome formation occurs as a localized sequence of biochemical activities
and associated morphological changes, which may be considered a form of signal
transduction leading to the construction of an organelle. Macropinocytosis may
also convey information about the availability of extracellular nutrients to
intracellular regulators of metabolism. Consistent with this idea, activation of
the metabolic regulator mechanistic target of rapamycin complex-1 (mTORC1) in
response to acute stimulation by growth factors and extracellular amino acids
requires internalization of amino acids by macropinocytosis. This suggests that
macropinocytosis is necessary for mTORC1-dependent growth of metazoan cells,
both as a route for delivery of amino acids to sensors associated with lysosomes
and as a platform for growth factor-dependent signalling to mTORC1 via
phosphatidylinositol 3-kinase (PI3K) and the Akt pathway. Because the
biochemical signals required for the construction of macropinosomes are also
required for cell growth, and inhibition of macropinocytosis inhibits growth
factor signalling to mTORC1, we propose that signalling by growth factor
receptors is organized into stochastic, structure-dependent cascades of chemical
reactions that both build a macropinosome and stimulate mTORC1. More generally,
as discrete units of signal transduction, macropinosomes may be subject to
feedback regulation by metabolism and cell dimensions. This article is part of
the Theo Murphy meeting issue 'Macropinocytosis'. In macropinocytosis, cells take up micrometre-sized droplets of medium into
internal vesicles. These vesicles are acidified and fused to lysosomes, their
contents digested and useful compounds extracted. Indigestible contents can be
exocytosed. Macropinocytosis has been known for approaching 100 years and is
described in both metazoa and amoebae, but not in plants or fungi. Its
evolutionary origin goes back to at least the common ancestor of the amoebozoa
and opisthokonts, with apparent secondary loss from fungi. The primary function
of macropinocytosis in amoebae and some cancer cells is feeding, but the
conserved processing pathway for macropinosomes, which involves shrinkage and
the retrieval of membrane to the cell surface, has been adapted in immune cells
for antigen presentation. Macropinocytic cups are large actin-driven processes,
closely related to phagocytic cups and pseudopods and appear to be organized
around a conserved signalling patch of PIP3, active Ras and active Rac that
directs actin polymerization to its periphery. Patches can form spontaneously
and must be sustained by excitable kinetics with strong cooperation from the
actin cytoskeleton. Growth-factor signalling shares core components with
macropinocytosis, based around phosphatidylinositol 3-kinase (PI3-kinase), and
we suggest that it evolved to take control of ancient feeding structures through
a coupled growth factor receptor. This article is part of the Theo Murphy
meeting issue 'Macropinocytosis'. Macropinocytosis is an evolutionarily conserved form of endocytosis that
mediates non-selective uptake of extracellular fluid and the solutes contained
therein. In mammalian cells, macropinocytosis is initiated by growth
factor-mediated activation of the Ras and PI3-kinase signalling pathways. In
maligt cells, oncogenic activation of growth factor signalling sustains
macropinocytosis cell autonomously. Recent studies of cancer metabolism,
discussed here, have begun to define a role for macropinocytosis as a nutrient
uptake route. Macropinocytic cancer cells ingest macromolecules in bulk and
break them down in the lysosome to support metabolism and macromolecular
synthesis. Thereby, macropinocytosis allows cells to tap into the copious
nutrient stores of extracellular macromolecules when canonical nutrients are
scarce. These findings demonstrate that macropinocytosis promotes metabolic
flexibility and resilience, which enables cancer cells to survive and grow in
nutrient-poor environments. Implications for physiological roles of growth
factor-stimulated macropinocytosis in cell metabolism and its relationship with
other nutrient uptake pathways are considered. This article is part of the Theo
Murphy meeting issue 'Macropinocytosis'. Macropinocytosis-the large-scale, non-specific uptake of fluid by cells-is used
by Dictyostelium discoideum amoebae to obtain nutrients. These cells form
circular ruffles around regions of membrane defined by a patch of
phosphatidylinositol (3,4,5)-trisphosphate (PIP3) and the activated forms of the
small G-proteins Ras and Rac. When this ruffle closes, a vesicle of the medium
is delivered to the cell interior for further processing. It is accepted that
PIP3 is required for efficient macropinocytosis. Here, we assess the roles of
Ras and Rac in Dictyostelium macropinocytosis. Gain-of-function experiments show
that macropinocytosis is stimulated by persistent Ras activation and genetic
analysis suggests that RasG and RasS are the key Ras proteins involved. Among
the activating guanine exchange factors (GEFs), GefF is implicated in
macropinocytosis by an insertional mutant. The individual roles of Rho family
proteins are little understood but activation of at least some may be
independent of PIP3. This article is part of the Theo Murphy meeting issue
'Macropinocytosis'. Macropinocytosis is an evolutionarily-conserved, large-scale, fluid-phase form
of endocytosis that has been ascribed different functions including antigen
presentation in macrophages and dendritic cells, regulation of receptor density
in neurons, and regulation of tumor growth under nutrient-limiting conditions.
However, whether macropinocytosis regulates the expansion of non-transformed
mammalian cells is unknown. Here we show that primary mouse and human T cells
engage in macropinocytosis that increases in magnitude upon T cell activation to
support T cell growth even under amino acid (AA) replete conditions.
Mechanistically, macropinocytosis in T cells provides access of extracellular AA
to an endolysosomal compartment to sustain activation of the mechanistic target
of rapamycin complex 1 (mTORC1) that promotes T cell growth. Our results thus
implicate a function of macropinocytosis in mammalian cell growth beyond
Ras-transformed tumor cells via sustained mTORC1 activation. Macropinocytosis refers to the non-specific uptake of extracellular fluid, which
plays ubiquitous roles in cell growth, immune surveillance, and virus entry.
Despite its widespread occurrence, it remains unclear how its initial cup-shaped
plasma membrane extensions form without any external solid support, as opposed
to the process of particle uptake during phagocytosis. Here, by developing a
computational framework that describes the coupling between the bistable
reaction-diffusion processes of active signaling patches and membrane
deformation, we demonstrated that the protrusive force localized to the edge of
the patches can give rise to a self-enclosing cup structure, without further
assumptions of local bending or contraction. Efficient uptake requires a balance
among the patch size, magnitude of protrusive force, and cortical tension.
Furthermore, our model exhibits cyclic cup formation, coexistence of multiple
cups, and cup-splitting, indicating that these complex morphologies
self-organize via a common mutually-dependent process of reaction-diffusion and
membrane deformation. |
Which was the first species in which a de novo gene emergence ("gene birth") was reported? | New genes can arise through duplication of a pre-existing gene or de novo from non-coding DNA, providing raw material for evolution of new functions in response to a changing environment. A prime example is the independent evolution of antifreeze glycoprotein genes (afgps) in the Arctic codfishes and Antarctic notothenioids to prevent freezing. | Novel protein-coding genes can arise either through re-organization of
pre-existing genes or de novo. Processes involving re-organization of
pre-existing genes, notably after gene duplication, have been extensively
described. In contrast, de novo gene birth remains poorly understood, mainly
because translation of sequences devoid of genes, or 'non-genic' sequences, is
expected to produce insignificant polypeptides rather than proteins with
specific biological functions. Here we formalize an evolutionary model according
to which functional genes evolve de novo through transitory proto-genes
generated by widespread translational activity in non-genic sequences. Testing
this model at the genome scale in Saccharomyces cerevisiae, we detect
translation of hundreds of short species-specific open reading frames (ORFs)
located in non-genic sequences. These translation events seem to provide
adaptive potential, as suggested by their differential regulation upon stress
and by signatures of retention by natural selection. In line with our model, we
establish that S. cerevisiae ORFs can be placed within an evolutionary continuum
ranging from non-genic sequences to genes. We identify ~1,900 candidate
proto-genes among S. cerevisiae ORFs and find that de novo gene birth from such
a reservoir may be more prevalent than sporadic gene duplication. Our work
illustrates that evolution exploits seemingly dispensable sequences to generate
adaptive functional innovation. The rearrangement of pre-existing genes has long been thought of as the major
mode of new gene generation. Recently, de novo gene birth from non-genic DNA was
found to be an alternative mechanism to generate novel protein-coding genes.
However, its functional role in human disease remains largely unknown. Here we
show that NCYM, a cis-antisense gene of the MYCN oncogene, initially thought to
be a large non-coding RNA, encodes a de novo evolved protein regulating the
pathogenesis of human cancers, particularly neuroblastoma. The NCYM gene is
evolutionally conserved only in the taxonomic group containing humans and
chimpanzees. In primary human neuroblastomas, NCYM is 100% co-amplified and
co-expressed with MYCN, and NCYM mRNA expression is associated with poor
clinical outcome. MYCN directly transactivates both NCYM and MYCN mRNA, whereas
NCYM stabilizes MYCN protein by inhibiting the activity of GSK3β, a kinase that
promotes MYCN degradation. In contrast to MYCN transgenic mice, neuroblastomas
in MYCN/NCYM double transgenic mice were frequently accompanied by distant
metastases, behavior reminiscent of human neuroblastomas with MYCN
amplification. The NCYM protein also interacts with GSK3β, thereby stabilizing
the MYCN protein in the tumors of the MYCN/NCYM double transgenic mice. Thus,
these results suggest that GSK3β inhibition by NCYM stabilizes the MYCN protein
both in vitro and in vivo. Furthermore, the survival of MYCN transgenic mice
bearing neuroblastoma was improved by treatment with NVP-BEZ235, a dual
PI3K/mTOR inhibitor shown to destabilize MYCN via GSK3β activation. In contrast,
tumors caused in MYCN/NCYM double transgenic mice showed chemo-resistance to the
drug. Collectively, our results show that NCYM is the first de novo evolved
protein known to act as an oncopromoting factor in human cancer, and suggest
that de novo evolved proteins may functionally characterize human disease. Genomes contain a large number of unique genes which have not been found in
other species. Although the origin of such "orphan" genes remains unclear, they
are thought to be involved in species-specific adaptive processes. Here, we
analyzed seven orphan genes (MoSPC1 to MoSPC7) prioritized based on in planta
expressed sequence tag data in the rice blast fungus, Magnaporthe oryzae.
Expression analysis using qRT-PCR confirmed the expression of four genes
(MoSPC1, MoSPC2, MoSPC3 and MoSPC7) during plant infection. However, individual
deletion mutants of these four genes did not differ from the wild-type strain
for all phenotypes examined, including pathogenicity. The length, GC contents,
codon adaptation index and expression during mycelial growth of the four genes
suggest that these genes formed during the evolutionary history of M. oryzae.
Synteny analyses using closely related fungal species corroborated the notion
that these genes evolved de novo in the M. oryzae genome. In this report, we
discuss our inability to detect phenotypic changes in the four deletion mutants.
Based on these results, the four orphan genes may be products of de novo gene
birth processes, and their adaptive potential is in the course of being tested
for retention or extinction through natural selection. De novo protein-coding gene origination is increasingly recognized as an
important evolutionary mechanism. However, there remains a large amount of
uncertainty regarding the frequency of these events and the mechanisms and speed
of gene establishment. Here, we describe a rigorous search for cases of de novo
gene origination in the great apes. We analyzed annotated proteomes as well as
full genomic DNA and transcriptional and translational evidence. It is notable
that results vary between database updates due to the fluctuating annotation of
these genes. Nonetheless we identified 35 de novo genes: 16 human-specific; 5
human and chimpanzee specific; and 14 that originated prior to the divergence of
human, chimpanzee, and gorilla and are found in all three genomes. The
taxonomically restricted distribution of these genes cannot be explained by loss
in other lineages. Each gene is supported by an open reading frame-creating
mutation that occurred within the primate lineage, and which is not polymorphic
in any species. Similarly to previous studies we find that the de novo genes
identified are short and frequently located near pre-existing genes. Also, they
may be associated with Alu elements and prior transcription and RNA-splicing at
the locus. Additionally, we report the first case of apparent independent
lineage sorting of a de novo gene. The gene is present in human and gorilla,
whereas chimpanzee has the ancestral noncoding sequence. This indicates a long
period of polymorphism prior to fixation and thus supports a model where de novo
genes may, at least initially, have a neutral effect on fitness. RNA-binding proteins (RBPs) control the fate of nearly every transcript in a
cell. However, no existing approach for studying these posttranscriptional gene
regulators combines transcriptome-wide throughput and biophysical precision.
Here, we describe an assay that accomplishes this. Using commonly available
hardware, we built a customizable, open-source platform that leverages the
inherent throughput of Illumina technology for direct biophysical measurements.
We used the platform to quantitatively measure the binding affinity of the
prototypical RBP Vts1 for every transcript in the Saccharomyces cerevisiae
genome. The scale and precision of these measurements revealed many previously
unknown features of this well-studied RBP. Our transcribed genome array (TGA)
assayed both rare and abundant transcripts with equivalent proficiency,
revealing hundreds of low-abundance targets missed by previous approaches. These
targets regulated diverse biological processes including nutrient sensing and
the DNA damage response, and implicated Vts1 in de novo gene "birth." TGA
provided single-nucleotide resolution for each binding site and delineated a
highly specific sequence and structure motif for Vts1 binding. Changes in
transcript levels in vts1Δ cells established the regulatory function of these
binding sites. The impact of Vts1 on transcript abundance was largely
independent of where it bound within an mRNA, challenging prevailing assumptions
about how this RBP drives RNA degradation. TGA thus enables a quantitative
description of the relationship between variant RNA structures, affinity, and in
vivo phenotype on a transcriptome-wide scale. We anticipate that TGA will
provide similarly comprehensive and quantitative insights into the function of
virtually any RBP. The phenomenon of de novo gene birth from junk DNA is surprising, because random
polypeptides are expected to be toxic. There are two conflicting views about how
de novo gene birth is nevertheless possible: the continuum hypothesis invokes a
gradual gene birth process, while the preadaptation hypothesis predicts that
young genes will show extreme levels of gene-like traits. We show that intrinsic
structural disorder conforms to the predictions of the preadaptation hypothesis
and falsifies the continuum hypothesis, with all genes having higher levels than
translated junk DNA, but young genes having the highest level of all. Results
are robust to homology detection bias, to the non-independence of multiple
members of the same gene family, and to the false positive annotation of
protein-coding genes. Accumulating evidence indicates that some protein-coding genes have originated
de novo from previously non-coding genomic sequences. However, the processes
underlying de novo gene birth are still enigmatic. In particular, the appearance
of a new functional protein seems highly improbable unless there is already a
pool of neutrally evolving peptides that are translated at significant levels
and that can at some point acquire new functions. Here, we use deep
ribosome-profiling sequencing data, together with proteomics and single
nucleotide polymorphism information, to search for these peptides. We find
hundreds of open reading frames that are translated and that show no
evolutionary conservation or selective constraints. These data suggest that the
translation of these neutrally evolving peptides may be facilitated by the
chance occurrence of open reading frames with a favourable codon composition. We
conclude that the pervasive translation of the transcriptome provides plenty of
material for the evolution of new functional proteins. The evolution of novel protein-coding genes from noncoding regions of the genome
is one of the most compelling pieces of evidence for genetic innovations in
nature. One popular approach to identify de novo genes is phylostratigraphy,
which consists of determining the approximate time of origin (age) of a gene
based on its distribution along a species phylogeny. Several studies have
revealed significant flaws in determining the age of genes, including de novo
genes, using phylostratigraphy alone. However, the rate of false positives in de
novo gene surveys, based on phylostratigraphy, remains unknown. Here, I
reanalyze the findings from three studies, two of which identified tens to
hundreds of rodent-specific de novo genes adopting a phylostratigraphy-centered
approach. Most putative de novo genes discovered in these investigations are no
longer included in recently updated mouse gene sets. Using a combination of
synteny information and sequence similarity searches, I show that ∼60% of the
remaining 381 putative de novo genes share homology with genes from other
vertebrates, originated through gene duplication, and/or share no synteny
information with nonrodent mammals. These results led to an estimated rate of
∼12 de novo genes per million years in mouse. Contrary to a previous study
(Wilson BA, Foy SG, Neme R, Masel J. 2017. Young genes are highly disordered as
predicted by the preadaptation hypothesis of de novo gene birth. Nat Ecol Evol.
1:0146), I found no evidence supporting the preadaptation hypothesis of de novo
gene formation. Nearly half of the de novo genes confirmed in this study are
within older genes, indicating that co-option of preexisting regulatory regions
and a higher GC content may facilitate the origin of novel genes. |
What are chromones? | The chromones are a class of chemical compounds characterised by the presence of the structure 5:6 benz-1:4-pyrone in their chemical make-up. | The chromones are a class of chemical compounds characterised by the presence of
the structure 5:6 benz-1:4-pyrone in their chemical make-up. The first chromone
in clinical use, khellin, was extracted from the seeds of the plant Ammi
visnaga, and had been used for centuries as a diuretic and as a smooth muscle
relaxant. Its use in bronchial asthma was reported in 1947. In the 1950s,
Benger's Laboratories embarked on a research programme to synthesise and develop
modifications of khellin for the treatment of asthma. New compounds were
screened using animal models to test the ability of the compound to prevent the
anaphylactic release of histamine and SRS-A (leukotrienes) from sensitised
guinea pig lung, and a human model to check the ability to reduce the
bronchoconstriction induced by inhaled antigen bronchial challenge. For initial
screening the human work was undertaken by Dr. R.E.C. Altounyan, who suffered
from allergic bronchial asthma and was employed by Benger's Laboratories. After
8 years and more than 600 challenges using over 200 compounds, in 1965 Altounyan
arrived at disodium cromoglycate (DSCG), the chromone that met the criteria of
providing more than 6 h of protection. DSCG is still used today as a mast cell
stabiliser. |
Which type of cancer has been suggested as a strategy for potential small-molecule inhibition of METTL3? | Small-molecule inhibition of METTL3 is a strategy against myeloid leukaemia. Targeting of RNA-modifying enzymes represents a promising avenue for anticancer therapy. | Author information:
(1)Milner Therapeutics Institute, University of Cambridge, Cambridge, UK.
(2)Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Cambridge,
UK.
(3)Storm Therapeutics Ltd, Cambridge, UK.
(4)Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge,
Cambridge, UK.
(5)Evotec (UK) Ltd, Abingdon, UK.
(6)The Center for the Study of Hematological Maligcies/Karaiskakio
Foundation, Nicosia, Cyprus.
(7)Division of Virology, Department of Pathology, University of Cambridge,
Cambridge, UK.
(8)MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre,
Cambridge, UK.
(9)The Gurdon Institute and Department of Pathology, University of Cambridge,
Cambridge, UK.
(10)Research Unit Apoptosis in Hematopoietic Stem Cells, Helmholtz Zentrum
München, German Research Center for Environmental Health (HMGU), Munich,
Germany.
(11)German Consortium for Translational Cancer Research (DKTK), Munich, Germany.
(12)Department of Pediatrics, Dr. von Hauner Children's Hospital, Ludwig
Maximilians University München, Munich, Germany.
(13)Storm Therapeutics Ltd, Cambridge, UK. [email protected].
(14)Milner Therapeutics Institute, University of Cambridge, Cambridge, UK.
[email protected].
(15)Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Cambridge,
UK. [email protected].
(16)Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge,
Cambridge, UK. [email protected].
(17)The Gurdon Institute and Department of Pathology, University of Cambridge,
Cambridge, UK. [email protected].
(18)Milner Therapeutics Institute, University of Cambridge, Cambridge, UK.
[email protected].
(19)The Gurdon Institute and Department of Pathology, University of Cambridge,
Cambridge, UK. [email protected].
(#)Contributed equally |
What is the mechanism of action of Lanifibranor? | Lanifibranor is peroxisome proliferator-activated receptor (PPAR) agonist. | Here, we describe the identification and synthesis of novel indole sulfonamide
derivatives that activate the three peroxisome proliferator activated receptor
(PPAR) isoforms. Starting with a PPARα activator, compound 4, identified during
a high throughput screening (HTS) of our proprietary screening library, a
systematic optimization led to the discovery of lanifibranor (IVA337) 5, a
moderately potent and well balanced pan PPAR agonist with an excellent safety
profile. In vitro and in vivo, compound 5 demonstrated strong activity in models
that are relevant to nonalcoholic steatohepatitis (NASH) pathophysiology
suggesting therapeutic potential for NASH patients. Background Non-alcoholic steatohepatitis (NASH), a multifactorial disease, can
progress to hepatic fibrosis and cirrhosis. The Peroxysomal
Proliferator-Activated Receptors, PPARα, β/δ and γ, play a central role in the
regulation of glucose and lipid metabolism and of the inflammatory and
fibrogenic pathways in liver and in other organs that all contribute to NASH
pathogenesis. Lanifibranor (IVA337), a panPPAR agonist, by acting on these three
different PPAR isotypes, combines pharmacological effects that could address the
different components of the disease as demonstrated in preclinical models.
Objectives NATIVE study (EudraCT: 2016-001979-70, NCT: NCT03008070) aims to
assess the safety and the efficacy of a 24-week treatment with lanifibranor (800
and 1200 mg/day) in adult non-cirrhotic NASH patients. The primary efficacy
endpoint is a 2-point reduction in the activity part of the Steatosis Activity
Fibrosis (SAF) histological score (combining inflammation and ballooning)
without worsening of fibrosis. Design NATIVE is a Phase 2b randomised,
placebo-controlled, double-blind, parallel-assignment, dose-range study.
Eligible adult patients with a confirmed histological diagnosis of NASH should
have a SAF Activity score of 3 or 4 (>2) and a SAF Steatosis score ≥ 1. There is
no specific criterion related to the fibrosis score except that patients with
cirrhosis (F4) were excluded. Summary This study will evaluate the efficacy of a
24-week treatment of NASH with lanifibranor based on histological evaluations
(SAF score) by biopsy. The number of responders according to the SAF Activity
score-based definition from baseline to 24 weeks will be compared between groups
and serves as primary endpoint. Liver fibrosis is the excessive expression and accumulation of extracellular
matrix proteins in the liver. Fibrotic scarring occurs as the consequence of
chronic injury and inflammation. While the successful treatment of hepatitis B
and C reduced the burden of liver disease related to viral hepatitis,
non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis
(NASH) are nowadays the leading causes of hepatic fibrosis worldwide. Although
basic research activities have significantly advanced our understanding of the
molecular disease pathogenesis, the present therapeutic options for fibrosis are
still limited. In advanced disease stages, liver transplantation often remains
the only curative treatment. This highlights the necessity of preventive
strategies to avoid complications of fibrosis, particularly cirrhosis, portal
hypertension and liver cancer. Lifestyle modifications (weight loss, exercise,
healthy diet) are the basis for prevention and treatment of NAFLD-associated
fibrosis. In the present review, we discuss recent advances in antifibrotic
prevention and therapy. In particular, we review the current concepts for
antifibrotic drug candidates in the treatment of NAFLD and NASH. While some
compounds aim at reverting pathogenic liver metabolism, an alternative approach
is to disconnect the injury (e.g., NAFLD) from inflammation and/or fibrosis.
Investigational drugs typically target metabolic pathways, insulin resistance,
hepatocyte death, inflammatory cell recruitment or activation, the gut-liver
axis, matrix expression or matrix turnover. While several promising drug
candidates failed in phase 2 or 3 clinical trials (including elafibranor,
emricasan and selonsertib), promising results with the farnesoid X receptor
agonist obeticholic acid, the pan-PPAR agonist lanifibranor and the chemokine
receptor CCR2/CCR5 inhibitor cenicriviroc support the expectation of an
effective pharmacological therapy for liver fibrosis in the near future.
Tackling NAFLD-associated fibrosis from different directions by combinatorial
drug treatment and effective lifestyle changes hold the greatest prospects. BACKGROUND: The TβRII∆k-fib transgenic (TG) mouse model of scleroderma
replicates key fibrotic and vasculopathic complications of systemic sclerosis
through fibroblast-directed upregulation of TGFβ signalling. We have examined
peroxisome proliferator-activated receptor (PPAR) pathway perturbation in this
model and explored the impact of the pan-PPAR agonist lanifibranor on the
cardiorespiratory phenotype.
METHODS: PPAR pathway gene and protein expression differences from TG and WT
sex-matched littermate mice were determined at baseline and following
administration of one of two doses of lanifibranor (30 mg/kg or 100 mg/kg) or
vehicle administered by daily oral gavage up to 4 weeks. The prevention of
bleomycin-induced lung fibrosis and SU5416-induced pulmonary hypertension by
lanifibranor was explored.
RESULTS: Gene expression data were consistent with the downregulation of the
PPAR pathway in the TβRII∆k-fib mouse model. TG mice treated with high-dose
lanifibranor demonstrated significant protection from lung fibrosis after
bleomycin and from right ventricular hypertrophy following induction of
pulmonary hypertension by SU5416, despite no significant change in right
ventricular systolic pressure.
CONCLUSIONS: In the TβRII∆k-fib mouse strain, treatment with 100 mg/kg
lanifibranor reduces the development of lung fibrosis and right ventricular
hypertrophy induced by bleomycin or SU5416, respectively. Reduced PPAR activity
may contribute to the exaggerated fibroproliferative response to tissue injury
in this transgenic model of scleroderma and its pulmonary complications. BACKGROUND: Management of nonalcoholic steatohepatitis (NASH) is an unmet
clinical need. Lanifibranor is a pan-PPAR (peroxisome proliferator-activated
receptor) agonist that modulates key metabolic, inflammatory, and fibrogenic
pathways in the pathogenesis of NASH.
METHODS: In this phase 2b, double-blind, randomized, placebo-controlled trial,
patients with noncirrhotic, highly active NASH were randomly assigned in a 1:1:1
ratio to receive 1200 mg or 800 mg of lanifibranor or placebo once daily for 24
weeks. The primary end point was a decrease of at least 2 points in the SAF-A
score (the activity part of the Steatosis, Activity, Fibrosis [SAF] scoring
system that incorporates scores for ballooning and inflammation) without
worsening of fibrosis; SAF-A scores range from 0 to 4, with higher scores
indicating more-severe disease activity. Secondary end points included
resolution of NASH and regression of fibrosis.
RESULTS: A total of 247 patients underwent randomization, of whom 103 (42%) had
type 2 diabetes mellitus and 188 (76%) had significant (moderate) or advanced
fibrosis. The percentage of patients who had a decrease of at least 2 points in
the SAF-A score without worsening of fibrosis was significantly higher among
those who received the 1200-mg dose, but not among those who received the 800-mg
dose, of lanifibranor than among those who received placebo (1200-mg dose vs.
placebo, 55% vs. 33%, P = 0.007; 800-mg dose vs. placebo, 48% vs. 33%,
P = 0.07). The results favored both the 1200-mg and 800-mg doses of lanifibranor
over placebo for resolution of NASH without worsening of fibrosis (49% and 39%,
respectively, vs. 22%), improvement in fibrosis stage of at least 1 without
worsening of NASH (48% and 34%, respectively, vs. 29%), and resolution of NASH
plus improvement in fibrosis stage of at least 1 (35% and 25%, respectively, vs.
9%). Liver enzyme levels decreased and the levels of the majority of lipid,
inflammatory, and fibrosis biomarkers improved in the lanifibranor groups. The
dropout rate for adverse events was less than 5% and was similar across the
trial groups. Diarrhea, nausea, peripheral edema, anemia, and weight gain
occurred more frequently with lanifibranor than with placebo.
CONCLUSIONS: In this phase 2b trial involving patients with active NASH, the
percentage of patients who had a decrease of at least 2 points in the SAF-A
score without worsening of fibrosis was significantly higher with the 1200-mg
dose of lanifibranor than with placebo. These findings support further
assessment of lanifibranor in phase 3 trials. (Funded by Inventiva Pharma;
NATIVE ClinicalTrials.gov number, NCT03008070.). |
Is the protein HOXA11 associated with endometrial disease? | Yes,
Low HOXA11 expression may promote the proliferation, migration, invasion of endometrial cancer cells | |
Summarize the function of DEAH helicase DHX36 and its role in G-quadruplex-dependent processes. | DEAH-Box helicase 36 (DHX36), a member of the large DExD/H box helicase family, enzymatically unwinds both G4 DNA and G4 RNA. RNA helicases of the DEAH/RHA family form a large and conserved class of enzymes that remodel RNA protein complexes (RNPs) by translocating along the RNA | Long non-coding RNAs (lncRNAs) are frequently dysregulated in a variety of human
cancers. However, their biological roles in these cancers remain incompletely
understood. In this study, we analyze the gene expression profiles of colon
cancer tissues and identify a previously unotated lncRNA, FLJ39051, that we
term GSEC (G-quadruplex-forming sequence containing lncRNA), as a lncRNA that is
upregulated in colorectal cancer. We further demonstrate that knockdown of GSEC
results in the reduction of colon cancer cell motility. We also show that GSEC
binds to the DEAH box polypeptide 36 (DHX36) RNA helicase via its
G-quadruplex-forming sequence and inhibits DHX36 G-quadruplex unwinding
activity. Moreover, knockdown of DHX36 restores the reduced migratory activity
of colon cancer cells caused by GSEC knockdown. These results suggest that GSEC
plays an important role in colon cancer cell migration by inhibiting the
function of DHX36 via its G-quadruplex structure. Single-stranded DNA (ssDNA) and RNA regions that include at least four closely
spaced runs of three or more consecutive guanosines strongly tend to fold into
stable G-quadruplexes (G4s). G4s play key roles as DNA regulatory sites and as
kinetic traps that can inhibit biological processes, but how G4s are regulated
in cells remains largely unknown. Here, we developed a kinetic framework for G4
disruption by DEAH-box helicase 36 (DHX36), the domit G4 resolvase in human
cells. Using tetramolecular DNA and RNA G4s with four to six G-quartets, we
found that DHX36-mediated disruption is highly efficient, with rates that depend
on G4 length under saturating conditions (kcat) but not under subsaturating
conditions (kcat/Km ). These results suggest that a step during G4 disruption
limits the kcat value and that DHX36 binding limits kcat/Km Similar results were
obtained for unimolecular DNA G4s. DHX36 activity depended on a 3' ssDNA
extension and was blocked by a polyethylene glycol linker, indicating that DHX36
loads onto the extension and translocates 3'-5' toward the G4. DHX36 unwound
dsDNA poorly compared with G4s of comparable intrinsic lifetime. Interestingly,
we observed that DHX36 has striking 3'-extension sequence preferences that
differ for G4 disruption and dsDNA unwinding, most likely arising from
differences in the rate-limiting step for the two activities. Our results
indicate that DHX36 disrupts G4s with a conventional helicase mechanism that is
tuned for great efficiency and specificity for G4s. The dependence of DHX36 on
the 3'-extension sequence suggests that the extent of formation of genomic G4s
may not track directly with G4 stability. Guanine-rich nucleic acid sequences challenge the replication, transcription,
and translation machinery by spontaneously folding into G-quadruplexes, the
unfolding of which requires forces greater than most polymerases can exert1,2.
Eukaryotic cells contain numerous helicases that can unfold G-quadruplexes 3 .
The molecular basis of the recognition and unfolding of G-quadruplexes by
helicases remains poorly understood. DHX36 (also known as RHAU and G4R1), a
member of the DEAH/RHA family of helicases, binds both DNA and RNA
G-quadruplexes with extremely high affinity4-6, is consistently found bound to
G-quadruplexes in cells7,8, and is a major source of G-quadruplex unfolding
activity in HeLa cell lysates 6 . DHX36 is a multi-functional helicase that has
been implicated in G-quadruplex-mediated transcriptional and
post-transcriptional regulation, and is essential for heart development,
haematopoiesis, and embryogenesis in mice9-12. Here we report the co-crystal
structure of bovine DHX36 bound to a DNA with a G-quadruplex and a 3'
single-stranded DNA segment. We show that the N-terminal DHX36-specific motif
folds into a DNA-binding-induced α-helix that, together with the OB-fold-like
subdomain, selectively binds parallel G-quadruplexes. Comparison with unliganded
and ATP-analogue-bound DHX36 structures, together with single-molecule
fluorescence resoce energy transfer (FRET) analysis, suggests that
G-quadruplex binding alone induces rearrangements of the helicase core; by
pulling on the single-stranded DNA tail, these rearrangements drive G-quadruplex
unfolding one residue at a time. RNA helicases of the DEAH/RHA family form a large and conserved class of enzymes
that remodel RNA protein complexes (RNPs) by translocating along the RNA. Driven
by ATP hydrolysis, they exert force to dissociate hybridized RNAs, dislocate
bound proteins or unwind secondary structure elements in RNAs. The sub-cellular
localization of DEAH-helicases and their concomitant association with different
pathways in RNA metabolism, such as pre-mRNA splicing or ribosome biogenesis,
can be guided by cofactor proteins that specifically recruit and simultaneously
activate them. Here we review the mode of action of a large class of
DEAH-specific adaptor proteins of the G-patch family. Defined only by their
eponymous short glycine-rich motif, which is sufficient for helicase binding and
stimulation, this family encompasses an immensely varied array of domain
compositions and is linked to an equally diverse set of functions. G-patch
proteins are conserved throughout eukaryotes and are even encoded within
retroviruses. They are involved in mRNA, rRNA and snoRNA maturation, telomere
maintece and the innate immune response. Only recently was the structural and
mechanistic basis for their helicase enhancing activity determined. We summarize
the molecular and functional details of G-patch-mediated helicase regulation in
their associated pathways and their involvement in human diseases. DHX36 is a eukaryotic DEAH/RHA family helicase that disrupts G-quadruplex
structures (G4s) with high specificity, contributing to regulatory roles of G4s.
Here we used a DHX36 truncation to examine the roles of the 13-amino acid
DHX36-specific motif (DSM) in DNA G4 recognition and disruption. We found that
the DSM promotes G4 recognition and specificity by increasing the G4 binding
rate of DHX36 without affecting the dissociation rate. Further, for most of the
G4s measured, the DSM has little or no effect on the G4 disruption step by
DHX36, implying that contacts with the G4 are maintained through the transition
state for G4 disruption. This result suggests that partial disruption of the G4
from the 3' end is sufficient to reach the overall transition state for G4
disruption, while the DSM remains unperturbed at the 5' end. Interestingly, the
DSM does not contribute to G4 binding kinetics or thermodynamics at low
temperature, indicating a highly modular function. Together, our results animate
recent DHX36 crystal structures, suggesting a model in which the DSM recruits
G4s in a modular and flexible manner by contacting the 5' face early in binding,
prior to rate-limiting capture and disruption of the G4 by the helicase core. Because of high stability and slow unfolding rates of G-quadruplexes (G4), cells
have evolved specialized helicases that disrupt these non-canonical DNA and RNA
structures in an ATP-dependent manner. One example is DHX36, a DEAH-box
helicase, which participates in gene expression and replication by recognizing
and unwinding parallel G4s. Here, we studied the molecular basis for the high
affinity and specificity of DHX36 for parallel-type G4s using all-atom molecular
dynamics simulations. By computing binding free energies, we found that the two
main G4-interacting subdomains of DHX36, DSM and OB, separately exhibit high G4
affinity but they act cooperatively to recognize two distinctive features of
parallel G4s: the exposed planar face of a guanine tetrad and the unique
backbone conformation of a continuous guanine tract, respectively. Our results
also show that DSM-mediated interactions are the main contributor to the binding
free energy and rely on making extensive van der Waals contacts between the
GXXXG motifs and hydrophobic residues of DSM and a flat guanine plane.
Accordingly, the sterically more accessible 5'-G-tetrad allows for more
favorable van der Waals and hydrophobic interactions which leads to the
preferential binding of DSM to the 5'-side. In contrast to DSM, OB binds to G4
mostly through polar interactions by flexibly adapting to the 5'-terminal
guanine tract to form a number of strong hydrogen bonds with the backbone
phosphate groups. We also identified a third DHX36/G4 interaction site formed by
the flexible loop missing in the crystal structure. |
What is the function of the YY1 transcriptional regulator? | The ubiquitous transcription factor Yin Yang 1 (YY1) is known to have a fundamental role in normal biologic processes such as embryogenesis, differentiation, replication, and cellular proliferation. YY1 is a transcription factor that can activate or repress transcription of a variety of genes and is involved in several developmental processes. YY1 overexpression and/or activation is associated with unchecked cellular proliferation, resistance to apoptotic stimuli, tumorigenesis and metastatic potential. YY1, in addition to its regulatory roles in normal biologic processes, may possess the potential to act as an initiator of tumorigenesis and may thus serve as both a diagnostic and prognostic tumor marker; furthermore, it may provide an effective target for antitumor chemotherapy and/or immunotherapy. | The assembly of multicomponent complexes at promoters, enhancers, and silencers
likely entails perturbations in the path of the DNA helix. We present evidence
that YY1, a ubiquitously expressed DNA-binding protein, regulates the activity
of the c-fos promoter primarily through an effect on DNA structure. YY1 binds to
and induces a phased DNA bend at three sites in this promoter. By use of a
truncated c-fos promoter activity containing a single functional YY1 site, we
show that YY1 represses promoter activity but that repression does not appear to
be an intrinsic property of the protein in this context. Moreover, when the
orientation of the YY1 site is reversed, YY1 activates the same promoter.
Repression by YY1 is also alleviated by changing the relative phasing of
factor-binding sites on either side of YY1. We conclude that the principal
function of YY1 in this promoter is to bend DNA to regulate contact between
other proteins. Thus, YY1 represents a new class of transcription factors that
influences promoter function by affecting promoter structure rather than by
directly contacting the transcriptional machinery. We provide evidence that the
product of the male sex determination gene SRY may also belong to this class of
structural factors. Fe65 is an adaptor protein that interacts with the Alzheimer beta-amyloid
precursor protein and is expressed mainly in the neurons of several regions of
the nervous system. The FE65 gene has a TATA-less promoter that drives an
efficient transcription in cells showing a neuronal phenotype, whereas its
efficiency is poor in non-neuronal cells. A short sequence encompassing the
transcription start site contains sufficient information to drive the
transcription in neuronal cells but not in non-neural cells. Electrophoretic
mobility-shift assays performed with rat brain nuclear extracts showed that
three major DNA-protein complexes, named BI, BII and BIII, are formed by the
FE65 minimal promoter. The proteins present in complexes BI and BII were
purified from bovine brain; internal microsequencing of the purified proteins
demonstrated that they corresponded to the previously isolated
single-stranded-DNA-binding protein Pur alpha, abundantly expressed in the
brain. In Chinese hamster ovary (CHO) cells, where the efficiency of FE65
promoter is very low, transient expression of Pur alpha increased the
transcription efficiency of the FE65 minimal promoter. By using oligonucleotide
competition and a specific antibody we demonstrated that the transcription
factor YY1 is responsible for the formation of complex BIII. Also in this case,
the transient expression of the YY1 cDNA in CHO cells resulted in an increased
transcription from the FE65 minimal promoter. The absence of any co-operative
effect when CHO cells were co-transfected with both YY1 and Pur alpha cDNA
species suggests that two different transcription regulatory mechanisms could
have a role in the regulation of the FE65 gene. To explore mechanisms for specificity of function within the family of E2F
transcription factors, we have identified proteins that interact with individual
E2F proteins. A two-hybrid screen identified RYBP (Ring1- and YY1-binding
protein) as a protein that interacts specifically with the E2F2 and E2F3 family
members, dependent on the marked box domain in these proteins. The Cdc6 promoter
contains adjacent E2F- and YY1-binding sites, and both are required for promoter
activity. In addition, YY1 and RYBP, in combination with either E2F2 or E2F3,
can stimulate Cdc6 promoter activity synergistically, dependent on the marked
box domain of E2F3. Using chromatin immunoprecipitation assays, we show that
both E2F2 and E2F3, as well as YY1 and RYBP, associate with the Cdc6 promoter at
G(1)/S of the cell cycle. In contrast, we detect no interaction of E2F1 with the
Cdc6 promoter. We suggest that the ability of RYBP to mediate an interaction
between E2F2 or E2F3 and YY1 is an important component of Cdc6 activation and
provides a basis for specificity of E2F function. The ubiquitous transcription factor Yin Yang 1 (YY1) is known to have a
fundamental role in normal biologic processes such as embryogenesis,
differentiation, replication, and cellular proliferation. YY1 exerts its effects
on genes involved in these processes via its ability to initiate, activate, or
repress transcription depending upon the context in which it binds. Mechanisms
of action include direct activation or repression, indirect activation or
repression via cofactor recruitment, or activation or repression by disruption
of binding sites or conformational DNA changes. YY1 activity is regulated by
transcription factors and cytoplasmic proteins that have been shown to abrogate
or completely inhibit YY1-mediated activation or repression; however, these
mechanisms have not yet been fully elucidated. Since expression and function of
YY1 are known to be intimately associated with progression through phases of the
cell cycle, the physiologic significance of YY1 activity has recently been
applied to models of tumor biology. The majority of the data are consistent with
the hypothesis that YY1 overexpression and/or activation is associated with
unchecked cellular proliferation, resistance to apoptotic stimuli, tumorigenesis
and metastatic potential. Studies involving hematopoetic tumors,
epithelial-based tumors, endocrine organ maligcies, hepatocellular carcinoma,
and retinoblastoma support this hypothesis. Molecular mechanisms that have been
investigated include YY1-mediated downregulation of p53 activity, interference
with poly-ADP-ribose polymerase, alteration in c-myc and nuclear factor-kappa B
(NF-kappaB) expression, regulation of death genes and gene products, and
differential YY1 binding in the presence of inflammatory mediators. Further,
recent findings implicate YY1 in the regulation of tumor cell resistance to
chemotherapeutics and immune-mediated apoptotic stimuli. Taken together, these
findings provide strong support of the hypothesis that YY1, in addition to its
regulatory roles in normal biologic processes, may possess the potential to act
as an initiator of tumorigenesis and may thus serve as both a diagnostic and
prognostic tumor marker; furthermore, it may provide an effective target for
antitumor chemotherapy and/or immunotherapy. YY1 is a transcription factor that can activate or repress transcription of a
variety of genes and is involved in several developmental processes. YY1 is a
repressor of transcription in differentiated H9C2 cells and in neonatal cardiac
myocytes but an activator of transcription in undifferentiated H9C2 cells. We
now present a detailed analysis of the functional domains of YY1 when it is
acting as a repressor or an activator and identify the mechanism whereby its
function is regulated in the differentiation of H9C2 cells. We show that histone
deacetylase 5 (HDAC5) is localized to the cytoplasm in undifferentiated H9C2
cells and that this localization is dependent on Ca(2+)/calmodulin-dependent
kinase IV (CaMKIV) and/or protein kinase D (PKD). In differentiated cells, HDAC5
is nuclear and interacts with YY1. Finally, we show that HDAC5 localization in
differentiated cells is dependent on phosphatase 2A (PP2A). Our results suggest
that a signaling mechanism that involves CaMKIV/PKD and PP2A controls YY1
function through regulation of HDAC5 and is important in the maintece of
muscle differentiation. Transcriptional complexes that contain peroxisome-proliferator-activated
receptor coactivator (PGC)-1alpha control mitochondrial oxidative function to
maintain energy homeostasis in response to nutrient and hormonal signals. An
important component in the energy and nutrient pathways is mammalian target of
rapamycin (mTOR), a kinase that regulates cell growth, size and survival.
However, it is unknown whether and how mTOR controls mitochondrial oxidative
activities. Here we show that mTOR is necessary for the maintece of
mitochondrial oxidative function. In skeletal muscle tissues and cells, the mTOR
inhibitor rapamycin decreased the gene expression of the mitochondrial
transcriptional regulators PGC-1alpha, oestrogen-related receptor alpha and
nuclear respiratory factors, resulting in a decrease in mitochondrial gene
expression and oxygen consumption. Using computational genomics, we identified
the transcription factor yin-yang 1 (YY1) as a common target of mTOR and
PGC-1alpha. Knockdown of YY1 caused a significant decrease in mitochondrial gene
expression and in respiration, and YY1 was required for rapamycin-dependent
repression of those genes. Moreover, mTOR and raptor interacted with YY1, and
inhibition of mTOR resulted in a failure of YY1 to interact with and be
coactivated by PGC-1alpha. We have therefore identified a mechanism by which a
nutrient sensor (mTOR) balances energy metabolism by means of the
transcriptional control of mitochondrial oxidative function. These results have
important implications for our understanding of how these pathways might be
altered in metabolic diseases and cancer. We showed earlier that p300/CBP plays an important role in G1 progression by
negatively regulating c-Myc and thereby preventing premature G1 exit. Here, we
have studied the mechanism by which p300 represses c-Myc and show that in
quiescent cells p300 cooperates with histone deacetylase 3 (HDAC3) to repress
transcription. p300 and HDAC3 are recruited to the upstream YY1-binding site of
the c-Myc promoter resulting in chromatin deacetylation and repression of c-Myc
transcription. Consistent with this, ablation of p300, YY1 or HDAC3 expression
results in chromatin acetylation and induction of c-Myc. These three proteins
exist as a complex in vivo and form a multiprotein complex with the YY1-binding
site in vitro. The C-terminal region of p300 is both necessary and sufficient
for the repression of c-Myc. These and other results suggest that in quiescent
cells the C-terminal region of p300 provides corepressor function and
facilitates the recruitment of p300 and HDAC3 to the YY1-binding site and
represses the c-Myc promoter. This corepressor function of p300 prevents the
inappropriate induction of c-Myc and S phase. Studies of coat color mutants have greatly contributed to the discovery of genes
that regulate melanocyte development and function. Here, we generated Yy1
conditional knockout mice in the melanocyte-lineage and observed profound
melanocyte deficiency and premature gray hair, similar to the loss of
melanocytes in human piebaldism and Waardenburg syndrome. Although YY1 is a
ubiquitous transcription factor, YY1 interacts with M-MITF, the Waardenburg
Syndrome IIA gene and a master transcriptional regulator of melanocytes. YY1
cooperates with M-MITF in regulating the expression of piebaldism gene KIT and
multiple additional pigmentation genes. Moreover, ChIP-seq identified
genome-wide YY1 targets in the melanocyte lineage. These studies mechanistically
link genes implicated in human conditions of melanocyte deficiency and reveal
how a ubiquitous factor (YY1) gains lineage-specific functions by co-regulating
gene expression with a lineage-restricted factor (M-MITF)-a general mechanism
which may confer tissue-specific gene expression in multiple lineages. During B cell development, long-distance DNA interactions are needed for V(D)J
somatic rearrangement of the immunoglobulin (Ig) loci to produce functional Ig
genes, and for class switch recombination (CSR) needed for antibody maturation.
The tissue-specificity and developmental timing of these mechanisms is a subject
of active investigation. A small number of factors are implicated in controlling
Ig locus long-distance interactions including Pax5, Yin Yang 1 (YY1), EZH2,
IKAROS, CTCF, cohesin, and condensin proteins. Here we will focus on the role
of YY1 in controlling these mechanisms. YY1 is a multifunctional transcription
factor involved in transcriptional activation and repression, X chromosome
inactivation, Polycomb Group (PcG) protein DNA recruitment, and recruitment of
proteins required for epigenetic modifications (acetylation, deacetylation,
methylation, ubiquitination, sumoylation, etc.). YY1 conditional knock-out
indicated that YY1 is required for B cell development, at least in part, by
controlling long-distance DNA interactions at the immunoglobulin heavy chain and
Igκ loci. Our recent data show that YY1 is also required for CSR. The mechanisms
implicated in YY1 control of long-distance DNA interactions include controlling
non-coding antisense RNA transcripts, recruitment of PcG proteins to DNA, and
interaction with complexes involved in long-distance DNA interactions including
the cohesin and condensin complexes. Though common rearrangement mechanisms
operate at all Ig loci, their distinct temporal activation along with the
ubiquitous nature of YY1 poses challenges for determining the specific
mechanisms of YY1 function in these processes, and their regulation at the
tissue-specific and B cell stage-specific level. The large numbers of
post-translational modifications that control YY1 functions are possible
candidates for regulation. Regulatory T (T(reg)) cells are essential for maintece of immune homeostasis.
Foxp3 is the key transcription factor for T(reg)-cell differentiation and
function; however, molecular mechanisms for its negative regulation are poorly
understood. Here we show that YY1 expression is lower in T(reg) cells than
T(conv) cells, and its overexpression causes a marked reduction of Foxp3
expression and abrogation of suppressive function of Treg cells. YY1 is
increased in T(reg) cells under inflammatory conditions with concomitant
decrease of suppressor activity in dextran sulfate-induced colitis model. YY1
inhibits Smad3/4 binding to and chromatin remodelling of the Foxp3 locus. In
addition, YY1 interrupts Foxp3-dependent target gene expression by physically
interacting with Foxp3 and by directly binding to the Foxp3 target genes. Thus,
YY1 inhibits differentiation and function of T(reg) cells by blocking Foxp3. |
Which CYP genes' expression is decreased at the in vivo level following pomegranate juice consumption? | It was found that pomegranate juice consumption decreased total hepatic CYP content as well as the expression of CYP1A2 and CYP3A. | Beneficial health effects have recently been claimed for pomegranate juice. In
vitro and in vivo studies have demonstrated its anti-atherosclerotic capacity,
chemoprevention and chemotherapy of prostate cancer, and antiproliferative,
apoptotic, and antioxidant activity, among others. On the other hand, there is a
complex interplay between tumor initiation, promotion, and progression and
xenobiotic biotranformation. This led us to investigate the effect of
pomegranate juice consumption on cytochrome P450 (CYP) activity and expression.
For this purpose, male mice consumed this fruit juice for 4 weeks, and
pentobarbital-induced sleeping time and total hepatic CYP content, activity, and
expression were evaluated. Moreover, the activity of CYP isoform 2E1 and
expression of the main CYP isoforms, namely, CYP1A1/2, CYP2E1, and CYP3A, were
also assessed. It was found that pomegranate juice consumption decreased total
hepatic CYP content as well as the expression of CYP1A2 and CYP3A. Prevention of
procarcinogen activation through CYP activity/expression inhibition may be
involved in pomegranate juice's effect on tumor initiation, promotion, and
progression. |
Class-defining mutations in which genes drive FLT3-ITD-mutant AML? | Advances in cancer genomics have revealed genomic classes of acute myeloid leukemia (AML) characterized by class-defining mutations, such as chimeric fusion genes or in genes such as NPM1, MLL, and CEBPA. These class-defining mutations frequently synergize with internal tandem duplications in FLT3 (FLT3-ITDs) to drive leukemogenesis. | Advances in cancer genomics have revealed genomic classes of acute myeloid
leukemia (AML) characterized by class-defining mutations, such as chimeric
fusion genes or in genes such as NPM1, MLL, and CEBPA. These class-defining
mutations frequently synergize with internal tandem duplications in FLT3
(FLT3-ITDs) to drive leukemogenesis. However, ∼20% of FLT3-ITD-positive AMLs
bare no class-defining mutations, and mechanisms of leukemic transformation in
these cases are unknown. To identify pathways that drive FLT3-ITD mutant AML in
the absence of class-defining mutations, we performed an insertional mutagenesis
(IM) screening in Flt3-ITD mice, using Sleeping Beauty transposons. All mice
developed acute leukemia (predomitly AML) after a median of 73 days. Analysis
of transposon insertions in 38 samples from Flt3-ITD/IM leukemic mice identified
recurrent integrations at 22 loci, including Setbp1 (20/38), Ets1 (11/38), Ash1l
(8/38), Notch1 (8/38), Erg (7/38), and Runx1 (5/38). Insertions at Setbp1 led
exclusively to AML and activated a transcriptional program similar, but not
identical, to those of NPM1-mutant and MLL-rearranged AMLs. Guide RNA targeting
of Setbp1 was highly detrimental to Flt3ITD/+/Setbp1IM+, but not to
Flt3ITD/+/Npm1cA/+, AMLs. Also, analysis of RNA-sequencing data from hundreds of
human AMLs revealed that SETBP1 expression is significantly higher in FLT3-ITD
AMLs lacking class-defining mutations. These findings propose that SETBP1
overexpression collaborates with FLT3-ITD to drive a subtype of human AML. To
identify genetic vulnerabilities of these AMLs, we performed genome-wide
CRISPR-Cas9 screening in Flt3ITD/+/Setbp1IM+ AMLs and identified potential
therapeutic targets, including Kdm1a, Brd3, Ezh2, and Hmgcr. Our study gives new
insights into epigenetic pathways that can drive AMLs lacking class-defining
mutations and proposes therapeutic approaches against such cases. |
Belzutifan has shown effectiveness for which diseases? | Belzutifan is the small-molecule HIF 2 alpha inhibitor that has demonstrated significant efficacy in the von Hippel-Lindau disease related renal cell carcinomas, hemangioblastomas, and pancreatic neuroendocrine tumors while demonstrating an acceptable safety profile | In a first, the FDA has approved an inhibitor of hypoxia-inducible factor-2α.
The drug is also the first approved to treat von Hippel-Lindau
disease-associated renal cell carcinoma, central nervous system
hemangioblastomas, and pancreatic neuroendocrine tumors. BACKGROUND: The 2021 American Society of Clinical Oncology (ASCO) Genitourinary
Cancers Symposium represents an unmissable event for oncologists who deal with
renal cell carcinoma (RCC).
AIM AND RESULTS: This article describes the main acquisitions of RCC management,
including the advent of a new combo (pembrolizumab+lenvatinib) as first-line
therapy, the confirmation of an OS advantage of ICI plus VEGFR-TKI combinations
over sunitinib at longer follow-up, the persistent benefit from these
combinations in particular subgroups (clear cell mRCC tumors with sarcomatoid
differentiation), and possible new approaches in subsequent lines of therapy
(including the HIF-2α inhibitor belzutifan).
CONCLUSIONS: This 2021 ASCO Genitourinary Cancer Symposium laid the foundations
for further knowledge development necessary for an increasingly personalized
management of mRCC. Belzutifan (Welireg™) is an oral small molecule inhibitor of hypoxia-inducible
factor (HIF)-2α being developed by Peloton Therapeutics for the treatment of
solid tumours, including renal cell carcinoma (RCC) with clear cell histology
(ccRCC) and von Hippel-Lindau (VHL) disease-associated RCC. In August 2021,
belzutifan received its first approval in the USA for the treatment of patients
with VHL disease who require therapy for associated RCC, central nervous system
(CNS) haemangioblastomas or pancreatic neuroendocrine tumours (pNET), not
requiring immediate surgery. Clinical studies of belzutifan (as monotherapy or
combination therapy) in other indications, including ccRCC, pNET and
phaeochromocytoma/paraganglioma, are also underway in various countries. This
article summarizes the milestones in the development of belzutifan leading to
this first approval for certain VHL disease-associated tumours. BACKGROUND: Patients with von Hippel-Lindau (VHL) disease have a high incidence
of renal cell carcinoma owing to VHL gene inactivation and constitutive
activation of the transcription factor hypoxia-inducible factor 2α (HIF-2α).
METHODS: In this phase 2, open-label, single-group trial, we investigated the
efficacy and safety of the HIF-2α inhibitor belzutifan (MK-6482, previously
called PT2977), administered orally at a dose of 120 mg daily, in patients with
renal cell carcinoma associated with VHL disease. The primary end point was
objective response (complete or partial response) as measured according to the
Response Evaluation Criteria in Solid Tumors, version 1.1, by an independent
central radiology review committee. We also assessed responses to belzutifan in
patients with non-renal cell carcinoma neoplasms and the safety of belzutifan.
RESULTS: After a median follow-up of 21.8 months (range, 20.2 to 30.1), the
percentage of patients with renal cell carcinoma who had an objective response
was 49% (95% confidence interval, 36 to 62). Responses were also observed in
patients with pancreatic lesions (47 of 61 patients [77%]) and central nervous
system hemangioblastomas (15 of 50 patients [30%]). Among the 16 eyes that could
be evaluated in 12 patients with retinal hemangioblastomas at baseline, all
(100%) were graded as showing improvement. The most common adverse events were
anemia (in 90% of the patients) and fatigue (in 66%). Seven patients
discontinued treatment: four patients voluntarily discontinued, one discontinued
owing to a treatment-related adverse event (grade 1 dizziness), one discontinued
because of disease progression as assessed by the investigator, and one patient
died (of acute toxic effects of fentanyl).
CONCLUSIONS: Belzutifan was associated with predomitly grade 1 and 2 adverse
events and showed activity in patients with renal cell carcinomas and non-renal
cell carcinoma neoplasms associated with VHL disease. (Funded by Merck Sharp and
Dohme and others; MK-6482-004 ClinicalTrials.gov number, NCT03401788.). |
Where are the PUX proteins found? | PUX proteins specifically associate with the nucleoskeleton underneath the INM. | In plants, AAA-adenosine triphosphatase (ATPase) Cell Division Control Protein
48 (CDC48) uses the force generated through ATP hydrolysis to pull, extract, and
unfold ubiquitylated or sumoylated proteins from the membrane, chromatin, or
protein complexes. The resulting changes in protein or RNA content are an
important means for plants to control protein homeostasis and thereby adapt to
shifting environmental conditions. The activity and targeting of CDC48 are
controlled by adaptor proteins, of which the plant ubiquitin regulatory X (UBX)
domain-containing (PUX) proteins constitute the largest family. Emerging
knowledge on the structure and function of PUX proteins highlights that these
proteins are versatile factors for plant homeostasis and adaptation that might
inspire biotechnological applications. |
Are Tregs CD4(+)CD25(+) regulatory T cells a positive regulator of the immune response? | CD4(+)CD25(+) regulatory T cells (Tregs) are negative regulators of the immune system that induce and maintain immune tolerance. | Immune activation during chronic HIV infection is a strong clinical predictor of
death and may mediate CD4(+) T cell depletion. Regulatory T cells (Tregs) are
CD4(+)CD25(bright)CD62L(high) cells that actively down-regulate immune
responses. We asked whether loss of Tregs during HIV infection mediates immune
activation in a cross-sectional study of 81 HIV-positive Ugandan volunteers. We
found that Treg number is strongly correlated with both CD4(+) and CD8(+) T cell
activation. In multivariate modeling, this relationship between Treg depletion
and CD4(+) T cell activation was stronger than any other clinical factor
examined, including viral load and absolute CD4 count. Tregs appear to decline
at different rates compared with other CD4(+) T cells, resulting in an increased
regulator to helper ratio in many patients with advanced disease. We hypothesize
that this skewing may contribute to T cell effector dysfunction. Our findings
suggest Tregs are a major contributor to the immune activation observed during
chronic HIV infection. CD4+CD25+ regulatory T cells (Tregs) are essential negative regulators of immune
responses. Here, we examined the signaling properties of human Tregs, using
CD4+CD25+ Treg and CD4+CD25- control (Tcont) cell lines generated from cord
blood. Treg cell lines were markedly hyporesponsive to stimulation with
dendritic cells and with anti-CD3/CD28-coated beads. Hyporesponsiveness was
reversed by exogenous interleukin-2 (IL-2). T-cell receptor
(TCR)-CD3/CD28-mediated activation of Rap1 and Akt was retained in Tregs, but
activation of Ras, mitogenactivated protein kinase 1/2 (MEK1/2), and
extracellular signal-regulated kinase 1/2 (Erk1/2) was impaired. Tregs were
blocked from cell cycle progression due to decrease of cyclin E and cyclin A and
increase of p27kip1 (p27kip cyclin dependent kinase inhibitor). IL-2 induced
sustained increase of cyclin E and cyclin A and prevented up-regulation of
p27kip1. Tregs had high susceptibility to apoptosis that was reversed by IL-2,
which correlated with activation of Erk1/2, up-regulation of Bcl-x(L) (B-cell
CLL/lymphoma 2-like nuclear gene encoding mitochondrial protein, transcript
variant 2), and phosphorylation of Bad (Bcl2 antagonist of cell death) at
Ser112. Thus, Tregs share biochemical characteristics of anergy, including
abortive activation of Ras-MEK-Erk, increased activation of Rap1, and increased
expression of p27kip1. In addition, our results indicate that
TCR-CD3/CD28-mediated and IL-2 receptor-mediated signals converge at the level
of MEK-Erk kinases to regulate Treg survival and expansion and suggest that
manipulation of the MEK-Erk axis may represent a novel strategy for Treg
expansion for immunotherapy. CD4+ T cells naturally expressing CD25 molecules (natural T regulatory cells
(Tregs)) have a role in maintaining self tolerance and in regulating responses
to infectious agents, transplantation Ags, and tumor Ags. CD4+ Tregs induced
from CD4+CD25- precursors (induced Tregs) also regulate immune responses in the
periphery. However, which of these Tregs is a major impediment in generating
antitumor CTL responses is not clear. We show that although the CD4+CD25+
subsets isolated from peripheral blood-derived lymphocytes do suppress the
proliferation of CD4+CD25- effector T cells, they do not suppress the activation
and expansion of the self but melanoma-associated, melanoma Ag-reactive T cell 1
(MART-1)27-35-specific CD8+ T cells stimulated by the respective peptide-loaded
matured dendritic cells in vitro. The CD4+CD25- counterparts, in contrast, lead
to the generation of CD25+ glucocorticoid-inducible TNFR+-Forkhead/winged helix
transcription factor+ populations and efficiently suppress the activation and
expansion of the MART-127-35 epitope-specific CTLs. Our data suggest that when
CTL precursors are optimally stimulated, natural Tregs are not a formidable
constraint toward generating a robust antitumor CTL response, but induced Tregs
could be. The immune system has evolved numerous mechanisms of peripheral T cell
immunoregulation, including a network of regulatory T (Treg) cells, to modulate
and down-regulate immune responses at various times and locations and in various
inflammatory circumstances. Amongst these, naturally occurring CD4(+)CD25(+)
Treg cells (nTreg) represent a major lymphocyte population engaged in the
domit control of self-reactive T responses and maintaining tolerance in
several models of autoimmunity. CD4(+)CD25(+) Treg cells differentiate in the
normal thymus as a functionally distinct subpopulation of T cells bearing a
broad T cell receptor repertoire, endowing these cells with the capacity to
recognize a wide range of self and nonself antigen specificities. The generation
of CD4(+)CD25(+) Treg cells in the immune system is genetically controlled,
influenced by antigen recognition, and various signals, in particular, cytokines
such as interleukin-2 and transforming growth factor-beta1, control their
activation, expansion, and suppressive effector activity. Functional abrogation
of these cells in vivo or genetic defects that affect their development or
function unequivocally promote the development of autoimmune and other
inflammatory diseases in animals and humans. Recent progress has shed light on
our understanding of the cellular and molecular basis of CD4(+)CD25(+) Treg
cell-mediated immune regulation. This article discusses the relative
contribution of CD4(+)CD25(+) nTreg cells in the induction of immunologic
self-tolerance and provides a comprehensive overview of recent finding regarding
the functional properties and effector mechanism of these cells, as revealed
from various in vitro and in vivo models. CD4(+)CD25(+) regulatory T cells (Treg) play a central role in the prevention of
autoimmunity and in the control of immune responses by down-regulating the
function of effector CD4(+) or CD8(+) T cells. The role of Treg in Mycobacterium
tuberculosis infection and persistence is inadequately documented. Therefore,
the current study was designed to determine whether CD4(+)CD25(+)FoxP3(+)
regulatory T cells may modulate immunity against human tuberculosis (TB). Our
results indicate that the number of CD4(+)CD25(+)FoxP3(+) Treg increases in the
blood or at the site of infection in active TB patients. The frequency of
CD4(+)CD25(+)FoxP3(+) Treg in pleural fluid inversely correlates with local
MTB-specific immunity (p<0.002). These CD4(+)CD25(+)FoxP3(+) T lymphocytes
isolated from the blood and pleural fluid are capable of suppressing
MTB-specific IFN-gamma and IL-10 production in TB patients. Therefore,
CD4(+)CD25(+)FoxP3(+) Treg expanded in TB patients suppress M. tuberculosis
immunity and may therefore contribute to the pathogenesis of human TB. CD4(+)CD25(+) regulatory T cells (Tregs) are considered to play a key role as
suppressors of immune mediated reactions. The analysis of Treg function in
patients with autoimmune, allergic or oncogenic diseases has emerged over the
past years. In the present study we describe a CFSE based protocol to measure
Treg mediated suppression of CD4(+) T cells. Measuring Treg suppressive capacity
towards proliferation of anti-CD3 Ab stimulated CD4(+)CD25(-) T cells in
coculture experiments by means of a CFSE based and a classical [(3)H]thymidine
incorporation assay gave similar results, provided that CD4(+)CD25(+) T cells
were anergic. However, when CD4(+)CD25(+) T cells proliferated upon mitogenic
stimulation, data obtained by the CFSE assay allowed the detection of a
significant Treg suppression whereas this was clearly underestimated using the
[(3)H]thymidine assay. In addition, an indirect CFSE based method was developed
to analyze antigen specific responses of total CD4(+) T cells and Treg depleted
CD4(+) T cells (i.e. CD4(+)CD25(-) T cells). Our results indicate that, in
healthy individuals, CD4(+) T cell responses against the multiple sclerosis (MS)
auto-antigens, myelin basic protein (MBP) and myelin oligodendrocyte
glycoprotein (MOG), were increased in Treg depleted CD4(+) T cells as compared
to total CD4(+) T cells. Our initial data suggest that Tregs in MS patients show
an impaired suppression of myelin reactive T cells when compared to healthy
controls. Moreover, this experimental setup permits the measurement of cytokine
production of the antigen proliferated CFSE(low) T cells by additional flow
cytometric analyses. In conclusion, the described CFSE based Treg suppression
assay is a valuable tool to study suppressor T cells in (auto)immune disorders. Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are
in widespread use due to their LDL reducing properties and concomitant
improvement of clinical outcome in patients with and without preexisting
atherosclerosis. Considerable evidence suggests that immune mediated mechanisms
play a domit role in the beneficial effects of statins. Naturally occurring
CD4(+)CD25(+) regulatory T cells (Tregs) have a key role in the prevention of
various inflammatory and autoimmune disorders by suppressing immune responses.
We tested the hypothesis that statins influence the circulating number and the
functional properties of Tregs. We studied the effects of in vivo and in vitro
statin treatment of human and murine mononuclear cells on the number of Tregs
and the expression level of their master transcription regulator, Foxp3.
Atorvastatin, but not mevastatin nor pravastatin, treatment of human peripheral
blood mononuclear cells (PBMCs) increased the number of CD4(+)CD25(high) cells,
and CD4(+)CD25(+)Foxp3(+) cells. These Tregs, induced by atorvastatin, expressed
high levels of Foxp3, which correlated with an increased regulatory potential.
Furthermore, co-culture studies revealed that atorvastatin induced
CD4(+)CD25(+)Foxp3(+) Tregs were derived from peripheral CD4(+)CD25(-)Foxp3(-)
cells. Simvastatin and pravastatin treatment in hyperlipidemic subjects
increased the number of Tregs. In C57BL/6 mice however, no effect of statins on
Tregs was evident. In conclusion, statins appear to significantly influence the
peripheral pool of Tregs in humans. This finding may shed light on the
mechanisms governing the plaque stabilizing properties of statins. Regulatory CD4(+) CD25(+) T (Treg) cells with the ability to suppress host
immune responses against self- or non-self antigens play important roles in the
processes of autoimmunity, transplant rejection, infectious diseases and
cancers. The proper regulation of CD4(+) CD25(+) Treg cells is thus critical for
optimal immune responses. Toll-like receptor (TLR)-mediated recognition of
specific structures of invading pathogens initiates innate as well as adaptive
immune responses via antigen-presenting cells (APCs). Interestingly, new
evidence suggests that TLR signalling may directly or indirectly regulate the
immunosuppressive function of CD4(+) CD25(+) Treg cells in immune responses. TLR
signalling may shift the balance between CD4(+) T-helper cells and Treg cells,
and subsequently influence the outcome of the immune response. This
immunomodulation pathway may therefore have potential applications in the
treatment of graft rejection, autoimmune diseases, infection diseases and
cancers. CD4(+)CD25(+) regulatory T cells (Tregs) are potent modulators of immune
responses. The transcriptional program distinguishing Tregs from the
CD4(+)CD25(-) Th cells is unclear. NFAT, a key transcription factor, is reported
to interact with forkhead box p3, allowing inhibitory and activating signals in
T cells. In the current study, we hypothesize that distinctive NFAT regulation
in Tregs as compared with Th cells, may contribute to specific functions of
these cells. Tregs express basal levels of cytoplasmic NFATc1 and NFATc2. In
contrast to Th cells, anti-CD3-mediated T cell activation did not induce nuclear
translocation of NFATc1 or NFATc2 in Tregs. This effect was associated with
altered regulation for NFAT in Tregs that included reduced calcium flux,
diminished calcineurin activation, and increased activity of glycogen synthase
kinase-3beta, a negative regulatory kinase for NFAT in Tregs relative to Th
cells. These data suggested that NFAT inhibition in Th cells may induce
regulatory function. Indeed, pharmacologically mediated NFAT inhibition induced
Th cells to function as Tregs, an effect that was mediated by induction of
membrane-bound TGF-beta on Th cells. Collectively, these data suggest that
maintaining NFAT at basal levels is a part of the transcriptional program
required for Tregs. BACKGROUND: Regulatory T cells (Tregs) are essential in the control of
tolerance. Evidence implicates Tregs in human autoimmune conditions. Here we
investigated their role in systemic sclerosis (SSc).
METHODS/PRINCIPAL FINDINGS: Patients were subdivided as having limited cutaneous
SSc (lcSSc, n = 20) or diffuse cutaneous SSc (dcSSc, n = 48). Further
subdivision was made between early dcSSc (n = 24) and late dcSSc (n = 24) based
upon the duration of disease. 26 controls were studied for comparison. CD3+
cells were isolated using FACS and subsequently studied for the expression of
CD4, CD8, CD25, FoxP3, CD127, CD62L, GITR, CD69 using flow cytometry. T cell
suppression assays were performed using sorted CD4CD25(high)CD127(-) and
CD4CD25(low)CD127(high) and CD3(+) cells. Suppressive function was correlated
with CD69 surface expression and TGFbeta secretion/expression. The frequency of
CD4(+)CD25(+) and CD25(high)FoxP3(high)CD127(neg) T cells was highly increased
in all SSc subgroups. Although the expression of CD25 and GITR was comparable
between groups, expression of CD62L and CD69 was dramatically lower in SSc
patients, which correlated with a diminished suppressive function. Co-incubation
of Tregs from healthy donors with plasma from SSc patients fully abrogated
suppressive activity. Activation of Tregs from healthy donors or SSc patients
with PHA significantly up regulated CD69 expression that could be inhibited by
SSc plasma.
CONCLUSIONS/SIGNIFICANCE: These results indicate that soluble factors in SSc
plasma inhibit Treg function specifically that is associated with altered Treg
CD69 and TGFbeta expression. These data suggest that a defective Treg function
may underlie the immune dysfunction in systemic sclerosis. The immunosuppressive effects of CD4+ CD25 high regulatory T cells (Tregs)
interfere with antitumor immune responses in cancer patients. Here, we present a
novel class of engineered human interleukin (IL)-2 analogs that antagonizes the
IL-2 receptor, for inhibiting regulatory T cell suppression. These antagonists
have been engineered for high affinity to the alpha subunit of the IL-2 receptor
and very low affinity to either the beta or gamma subunit, resulting in a
signaling-deficient IL-2 analog that sequesters the IL-2 receptor alpha subunit
from wild type IL-2. Two variants, "V91R" and "Q126T" with residue substitutions
that disrupt the beta and gamma subunit binding interfaces, respectively, have
been characterized in both a T cell line and in human primary Tregs. These
mutants retain their high affinity binding to IL-2 receptor alpha subunit, but
do not activate STAT5 phosphorylation or stimulate T cell growth. The 2 mutants
competitively antagonize wild-type IL-2 signaling through the IL-2 receptor with
similar efficacy, with inhibition constants of 183 pM for V91R and 216 pM for
Q126T. Here, we present a novel approach to CD25-mediated Treg inhibition, with
the use of an engineered human IL-2 analog that antagonizes the IL-2 receptor. CD4(+)CD25(+) regulatory T cells (Tregs) are critical for the peripheral immune
tolerance. Understanding the signals for the generation of Tregs is important
for the clinical immunotherapy, but only limited progress has been made on
obtaining enough peripheral Tregs. The aim of this study was to evaluate the
role of trichosanthin (Tk) extracted from Chinese medicinal herb Trichosanthes
kirilowi on the function of Tregs in vitro and in vivo. We reported here that Tk
is needed for the expansion of freshly isolated CD4(+)CD25(+)Tregs (nTregs) into
Tk-expanded CD4(+)CD25(+)Tregs (Tk-Tregs) through up-regulating CD25 and Foxp3
expression. The dose-response analyses indicated that 100 ng/ml Tk was the most
appropriate dose. The result of real-time PCR showed that Tk-Tregs expressed
1.5-fold higher levels of Foxp3 than those observed in nTregs. Tk-Tregs markedly
suppressed activation of effector T cells at a suppressor/responder ratio of
1:1, 1:2, 1:4, 1:8 or 1:16, and their effect was dose dependent. Moreover,
Tk-Tregs secreted more immunosuppressive cytokines interleukin (IL)-10 and
transforming growth factor (TGF)-beta1 after stimulating with antigen and
antigen-presenting cells (APC). Transwell experiments showed that not only
cell-to-cell contact but also soluble cytokines were involved in suppressive
mechanism of Tk-Tregs. And Tk-Tregs were more efficient in suppressing CD25(-)T
cell response to specific antigen than to irrelative antigen. Most importantly,
it was revealed for the first time that Tk-Tregs could prolong the survival
duration of mice with acute graft-versus-host disease (aGVHD). In conclusion,
the study suggests a possible therapeutic potential of Tk-Tregs for clinical
treatment on aGVHD. α7 Nicotinic acetylcholine receptor (α7 nAChR) has been found in several
non-neuronal cells and is described as an important regulator of cellular
function. Naturally occurring CD4(+)CD25(+) regulatory T cells (Tregs) are
essential for the active suppression of autoimmunity. The present study
investigated whether naturally occurring Tregs expressed α7 nAChR and
investigated the functionary role of this receptor in controlling suppressive
activity of these cells. We found that CD4(+)CD25(+) Tregs from naive C57BL/6J
mice positively expressed α7 nAChR, and its activation by nicotine enhanced the
suppressive capacity of Tregs. Nicotine stimulation up-regulated the expression
of cytotoxic T-lymphocyte-associated antigen (CTLA)-4 and forkhead/winged helix
transcription factor p3 (Foxp3) on Tregs but had no effect on the production of
interleukin (IL)-10 and transforming growth factor-β1 by Tregs. In the
supernatants of CD4(+)CD25(+) Tregs/CD4(+)CD25(-) T-cell cocultures, we observed
a decrease in the concentration of IL-2 in nicotine-stimulated groups, but
nicotine stimulation had no effect on the ratio of IL-4/interferon (IFN)-γ,
which partially represented T-cell polarization. The above-mentioned effects of
nicotine were reversed by a selective α7 nAChR antagonist, α-bungarotoxin. In
addition, the ratio of IL-4/IFN-γ was increased by treatment with
α-bungarotoxin. We conclude that nicotine might increase Treg-mediated immune
suppression of lymphocytes via α7 nAChR. The effect is related to the
up-regulation of CTLA-4 as well as Foxp3 expression and decreased IL-2 secretion
in CD4(+)CD25(+) Tregs/CD4(+)CD25(-) T-cell coculture supernatants. α7 nAChR
seems to be a critical regulator for immunosuppressive function of CD4(+)CD25(+)
Tregs. BACKGROUND: Because CD4CD25Foxp3 regulatory T cells (Tregs) are essential for
the maintece of self-tolerance, significant interest surrounds the
developmental cues for thymic-derived natural Tregs (nTregs) and
periphery-generated adaptive Tregs (aTregs). In the transplant setting, the
allograft may play a role in the generation of alloantigen-specific Tregs, but
this role remains undefined. We examined whether the immune response to a
transplant allograft results in the peripheral generation of aTregs.
METHODS: To identify generation of aTregs, purified graft-reactive CD4CD25 T
cells were adoptively transferred to mice-bearing skin allograft. To demonstrate
that aTregs are necessary for tolerance, DBA/2 skin was transplanted onto
C57BL/6-RAG-1-deficient recipients adoptively transferred with purified sorted
CD4CD25 T cells; half of the recipients undergo tolerance induction treatment.
RESULTS: By tracking adoptively transferred cells, we show that purified
graft-reactive CD4CD25 T lymphocytes up-regulate Foxp3 in mice receiving skin
allografts in the absence of any treatment. Interestingly, cotransfer of
antigen-specific nTregs suppresses the up-regulation of Foxp3 by inhibiting the
proliferation of allograft-responsive T cells. In vitro data are consistent with
our in vivo data-Foxp3 cells are generated on antigen activation, and this
generation is suppressed on coculture with antigen-specific nTregs. Finally,
blocking aTreg generation in grafted, rapamycin-treated mice disrupts
alloantigen-specific tolerance induction. In contrast, blocking aTreg generation
in grafted mice treated with nondepleting anti-CD4 plus anti-CD40L antibodies
does not disrupt graft tolerance.
CONCLUSIONS: We conclude that graft alloantigen stimulates the de novo
generation of aTregs, and this generation may represent a necessary step in some
but not all protocols of tolerance induction. CD25(High) CD4+ regulatory T cells (Treg cells) have been described as key
players in immune regulation, preventing infection-induced immune pathology and
limiting collateral tissue damage caused by vigorous anti-parasite immune
response. In this review, we summarize data obtained by the investigation of
Treg cells in different clinical forms of Chagas' disease. Ex vivo
immunophenotyping of whole blood, as well as after stimulation with Trypanosoma
cruzi antigens, demonstrated that individuals in the indeterminate (IND)
clinical form of the disease have a higher frequency of Treg cells, suggesting
that an expansion of those cells could be beneficial, possibly by limiting
strong cytotoxic activity and tissue damage. Additional analysis demonstrated an
activated status of Treg cells based on low expression of CD62L and high
expression of CD40L, CD69, and CD54 by cells from all chagasic patients after T.
cruzi antigenic stimulation. Moreover, there was an increase in the frequency of
the population of Foxp3+ CD25(High)CD4+ cells that was also IL-10+ in the IND
group, whereas in the cardiac (CARD) group, there was an increase in the
percentage of Foxp3+ CD25(High) CD4+ cells that expressed CTLA-4. These data
suggest that IL-10 produced by Treg cells is effective in controlling disease
development in IND patients. However, in CARD patients, the same regulatory
mechanism, mediated by IL-10 and CTLA-4 expression is unlikely to be sufficient
to control the progression of the disease. These data suggest that Treg cells
may play an important role in controlling the immune response in Chagas' disease
and the balance between regulatory and effector T cells may be important for the
progression and development of the disease. Additional detailed analysis of the
mechanisms on how these cells are activated and exert their function will
certainly give insights for the rational design of procedure to achieve the
appropriate balance between protection and pathology during parasite infections. Accumulating evidence has demonstrated that naturally occurring CD4(+)CD25(+)
regulatory T cells (Tregs) are critical for maintece of immunological
tolerance and have been shown to be important in regulating the immune responses
in many diseases. Curcumin, a phytochemical obtained from the rhizome of the
plant Curcuma longa, has achieved the potential therapeutic interest to numerous
immune-related disorders. However, the effect and mechanism of curcumin on Tregs
remain largely elusive. In the present study, curcumin inhibition of the
suppressive activity of CD4(+)CD25(+) regulatory T cells appears to be dependent
on three categories: inhibiting cell-cell contact by down-regulation of CTLA-4,
suppressing inhibitory cytokine secretion and decreasing the ability to consume
IL-2 and/or suppress IL-2 production. In addition, Foxp3 expression was also
reduced on Tregs after curcumin stimulation. Moreover, we found that nuclear
translocation of p65 and c-Rel, which is critical for Foxp3 and CD25
expressions, was markedly decreased in Tregs with curcumin stimulation. Based on
the role of curcumin in the suppressive activity of Tregs, it may be feasible to
use curcumin as an immunotherapy for Treg-related diseases, such as tumors and
sepsis. OBJECTIVES: CD4CD25 regulatory T cells (Tregs) play a key role in the prevention
of various inflammatory and autoimmune disorders by suppressing immune
responses. The beneficial effect of statins on myocardial ischemia-reperfusion
injury (IRI) depends in part on their immunomodulatory and anti-inflammatory
mechanisms. We aimed to determine whether Tregs contribute to statin-induced
cardioprotection against myocardial IRI.
METHODS: Thirty-two rats were divided into four groups: sham,
ischemia-reperfusion (IR), rosuvastatin (RSV)/IR, and mevalonic acid
(MVA)+RSV/IR. Myocardial IR was induced by a 30-min coronary occlusion, followed
by a 48-h reperfusion. RSV (5 mg/kg) was administered intravenously 18 h before
IR. The rats were killed after 48-h reperfusion. Serum cardiac troponin I (cTnI)
was measured by ELISA, infiltration of inflammatory cells in myocardium by
hematoxylin and eosin staining, expression of FoxP3 protein by western blotting,
accumulation of Tregs in myocardium by immunohistochemical examination, and
infarct size by TTC staining.
RESULTS: Significant elevation in serum cTnI, enlarged infarct size, and marked
infiltration of inflammatory cells in myocardium were observed in the IR group.
The administration of RSV significantly reduced the serum cTnI level, attenuated
the accumulation of inflammatory cells, decreased infarct size, and increased
the FoxP3 expression and Treg accumulation in myocardium compared with the IR
group. The combination of RSV and MVA pretreatment partially abolished the
anti-inflammatory and infarct size-limiting effects and completely reversed Treg
accumulation in myocardium induced by RSV. The accumulation of inflammatory
cells was negatively correlated with FoxP3 expression and Treg accumulation in
the ischemic myocardium.
CONCLUSION: RSV pretreatment was associated with more Treg accumulation, less
inflammatory response, and myocardial injury, suggesting that such
cardioprotection against IRI was partially mediated by Treg-negative modulation
of inflammation response, probably through the HMG-CoA reductase pathway. It is well established that CD4CD25 regulatory T cells (Tregs) downregulate
inflammatory immune responses and help to maintain immune homeostasis. Recent
reports have shown that ligation of germline encoded pattern recognition
receptors such as Toll-like receptors can stimulate Tregs and therefore
implicate Tregs in the pathophysiology of sepsis and other inflammatory
diseases. In this report, we show that injection of lipopolysaccharide (LPS)
leads to expansion of CD4CD25FoxP3 Tregs, suggesting that these cells may play
an important role in immune regulation in LPS-induced acute inflammation.
Indeed, genetic or immunological inhibition of Treg function using mice lacking
functional Tregs (CD25 KO mice) or anti-CD25 monoclonal antibody (anti-CD25
mAb), respectively, led to acute death in an otherwise nonlethal LPS challenge.
This was accompanied by exaggerated production of proinflammatory cytokines.
Strikingly, adoptive transfer of CD4CD25 Tregs to CD25 KO mice before LPS
challenge rescues mice from death. Unlike LPS, depletion of Tregs followed by
concanavalin A (Con A) challenge does not result in mortality, suggesting that
Treg depletion does not globally influence all models of acute inflammation. We
authenticate our findings by showing that depletion of Tregs leads to mortality
in a nonlethal Escherichia coli challenge accompanied by elevated serum levels
of proinflammatory cytokines. Collectively, our results indicate that in
addition to regulation of LPS-induced acute inflammation, Tregs help to improve
bacterial clearance and promote survival in an acute model of bacterial
infection. BACKGROUND: Alteration of regulatory T cells (Tregs) may contribute to
ineffective suppression of proinflammatory cytokines in type 1 diabetes.
AIM: We determined the percentage of Tregs expressing CD62L or tumor necrosis
factor receptor type 2 (TNFR2) in 70 young type 1 diabetic patients compared
with 30 controls and assessed their relation to inflammation, glycemic control
and micro-vascular complications.
METHODS: High-sensitivity C-reactive protein (hs-CRP), hemoglobin A1c (HbA1c),
tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) were assessed
with flow cytometric analysis of Tregs, Tregs expressing CD62L or TNFR2.
RESULTS: The percentage of CD4(+)CD25(high) T cells and
CD4(+)CD25(high)CD62L(high) cells were significantly decreased while
CD4(+)CD25(high)TNFR2(+) T cells were elevated in patients with micro-vascular
complications than those without and controls (p<0.001). ROC curve revealed that
the cutoff values of Tregs, Tregs expressing CD62L and Tregs expressing TNFR2
(7.46%, 24.2% and 91.9%, respectively) could detect micro-vascular
complications. Significant negative correlations were observed between Tregs
expressing CD62L and disease duration, FBG, HbA1c, urinary albumin excretion and
hs-CRP, whereas, positive correlations were found between Tregs expressing TNFR2
and these variables (p<0.05). TNF-α was significantly increased while IL-10 was
decreased among patients with micro-vascular complications than those without
(p<0.05).
CONCLUSIONS: Alteration in the frequency of Tregs and Tregs expressing CD62L or
TNFR2 in type 1 diabetes is associated with increased inflammation, poor
glycemic control and risk of micro-vascular complications. Not all T cells are effector cells of the anti-tumor immune system. One of the
subpopulations of CD4+ T cells that express CD25+ and the transcription factor
FOXP3, known as Regulator T cells (TReg), plays an essential role in maintaining
tolerance and immune homeostasis preventing autoimmune diseases, minimalize
chronic inflammatory diseases by enlisting various immunoregulatory mechanisms.
The balance between effector T cells (Teff) and regulator T cells is crucial in
determining the outcome of an immune response. Regarding tumors, activation or
expansion of TReg cells reduces anti-tumor immunity. TReg cells inhibit the
activation of CD4+ and CD8+ T cells and suppress anti-tumor activity in the
tumor microenvironment. In addition, TReg cells also promote tumor angiogenesis
both directly and indirectly to ensure oxygen and nutrient transport to the
tumor. There is accumulating evidence showing a positive result that removing or
suppressing TReg cells increases anti-tumor immune response. However, depletion
of TReg cells will cause autoimmunity. One strategy to improve or restore tumor
immunity is targeted therapy on the domit effector TReg cells in tumor
tissue. Various molecules such as CTLA-4, CD4, CD25, GITR, PD-1, OX40, ICOS are
in clinical trials to assess their role in attenuating TReg cells' function. |
Is Mediator present at super enhancers? | Yes. Super enhancers are clusters of enhancers that are densely occupied by the master regulator and mediator. | The HSA21 encoded Single-minded 2 (SIM2) transcription factor has key
neurological functions and is a good candidate to be involved in the cognitive
impairment of Down syndrome. We aimed to explore the functional capacity of SIM2
by mapping its DNA binding sites in mouse embryonic stem cells. ChIP-sequencing
revealed 1229 high-confidence SIM2-binding sites. Analysis of the SIM2 target
genes confirmed the importance of SIM2 in developmental and neuronal processes
and indicated that SIM2 may be a master transcription regulator. Indeed, SIM2
DNA binding sites share sequence specificity and overlapping domains of
occupancy with master transcription factors such as SOX2, OCT4 (Pou5f1), NANOG
or KLF4. The association between SIM2 and these pioneer factors is supported by
co-immunoprecipitation of SIM2 with SOX2, OCT4, NANOG or KLF4. Furthermore, the
binding of SIM2 marks a particular sub-category of enhancers known as
super-enhancers. These regions are characterized by typical DNA modifications
and Mediator co-occupancy (MED1 and MED12). Altogether, we provide evidence that
SIM2 binds a specific set of enhancer elements thus explaining how SIM2 can
regulate its gene network in neuronal features. Super-enhancers (SEs), which are composed of large clusters of enhancers densely
loaded with the Mediator complex, transcription factors and chromatin
regulators, drive high expression of genes implicated in cell identity and
disease, such as lineage-controlling transcription factors and oncogenes. BRD4
and CDK7 are positive regulators of SE-mediated transcription. By contrast,
negative regulators of SE-associated genes have not been well described. Here we
show that the Mediator-associated kinases cyclin-dependent kinase 8 (CDK8) and
CDK19 restrain increased activation of key SE-associated genes in acute myeloid
leukaemia (AML) cells. We report that the natural product cortistatin A (CA)
selectively inhibits Mediator kinases, has anti-leukaemic activity in vitro and
in vivo, and disproportionately induces upregulation of SE-associated genes in
CA-sensitive AML cell lines but not in CA-insensitive cell lines. In AML cells,
CA upregulated SE-associated genes with tumour suppressor and
lineage-controlling functions, including the transcription factors CEBPA, IRF8,
IRF1 and ETV6 (refs 6-8). The BRD4 inhibitor I-BET151 downregulated these
SE-associated genes, yet also has anti-leukaemic activity. Individually
increasing or decreasing the expression of these transcription factors
suppressed AML cell growth, providing evidence that leukaemia cells are
sensitive to the dosage of SE-associated genes. Our results demonstrate that
Mediator kinases can negatively regulate SE-associated gene expression in
specific cell types, and can be pharmacologically targeted as a therapeutic
approach to AML. Super-enhancers are characterized by high levels of Mediator binding and are
major contributors to the expression of their associated genes. They exhibit
high levels of local chromatin interactions and a higher order of local
chromatin organization. On the other hand, lncRNAs can localize to specific DNA
sites by forming a RNA:DNA:DNA triplex, which in turn can contribute to local
chromatin organization. In this paper, we characterize a new class of lncRNAs
called super-lncRNAs that target super-enhancers and which can contribute to the
local chromatin organization of the super-enhancers. Using a logistic regression
model based on the number of RNA:DNA:DNA triplex sites a lncRNA forms within the
super-enhancer, we identify 442 unique super-lncRNA transcripts in 27 different
human cell and tissue types; 70% of these super-lncRNAs were tissue restricted.
They primarily harbor a single triplex-forming repeat domain, which forms an
RNA:DNA:DNA triplex with multiple anchor DNA sites (originating from
transposable elements) within the super-enhancers. Super-lncRNAs can be grouped
into 17 different clusters based on the tissue or cell lines they target.
Super-lncRNAs in a particular cluster share common short structural motifs and
their corresponding super-enhancer targets are associated with gene ontology
terms pertaining to the tissue or cell line. Super-lncRNAs may use these
structural motifs to recruit and transport necessary regulators (such as
transcription factors and Mediator complexes) to super-enhancers, influence
chromatin organization, and act as spatial amplifiers for key tissue-specific
genes associated with super-enhancers. A number of studies have recently demonstrated that super-enhancers, which are
large cluster of enhancers typically marked by a high level of acetylation of
histone H3 lysine 27 and mediator bindings, are frequently associated with genes
that control and define cell identity during normal development. Super-enhancers
are also often enriched at cancer genes in various maligcies. The
identification of such enhancers would pinpoint critical factors that directly
contribute to pathogenesis. In this study, we performed enhancer profiling using
primary leukemia samples from adult T-cell leukemia/lymphoma (ATL), which is a
genetically heterogeneous intractable cancer. Super-enhancers were enriched at
genes involved in the T-cell activation pathway, including IL2RA/CD25, CD30, and
FYN, in both ATL and normal mature T cells, which reflected the origin of the
leukemic cells. Super-enhancers were found at several known cancer gene loci,
including CCR4, PIK3R1, and TP73, in multiple ATL samples, but not in normal
mature T cells, which implicated those genes in ATL pathogenesis. A
small-molecule CDK7 inhibitor, THZ1, efficiently inhibited cell growth, induced
apoptosis, and downregulated the expression of super-enhancer-associated genes
in ATL cells. Furthermore, enhancer profiling combined with gene expression
analysis identified a previously uncharacterized gene, TIAM2, that was
associated with super-enhancers in all ATL samples, but not in normal T cells.
Knockdown of TIAM2 induced apoptosis in ATL cell lines, whereas overexpression
of this gene promoted cell growth. Our study provides a novel strategy for
identifying critical cancer genes. |
Does atemoya juice inhibit the CYP1A2 enzyme? | Yes, atemoya juice inhibits the CYP1A2 enzyme. | BACKGROUND AND OBJECTIVES: Atemoya (Annona atemoya) is increasingly being
consumed worldwide because of its pleasant taste. However, only limited
information is available concerning possible atemoya-drug interactions. In the
present study, the issue of whether atemoya shows food-drug interactions with
substrate drugs of the major drug-metabolizing cytochrome P450s (i.e., CYP1A2,
CYP2C9, and CYP3A) is addressed.
METHODS: The ability of atemoya juice to inhibit the activities of phenacetin
O-deethylase (CYP1A2), diclofenac 4'-hydroxylase (CYP2C9), and midazolam
1'-hydroxylase (CYP3A) was examined in vitro using human and rat liver
microsomes. The in vivo pharmacokinetics of phenacetin and metabolites derived
from it in rats when atemoya juice or fluvoxamine (a CYP1A2 inhibitor) was
preadministered were also investigated.
RESULTS: Atemoya juice significantly inhibited CYP1A2 activity in human liver
microsomes, but not the activities of CYP2C9 and CYP3A. In spite of this
inhibition, preadministration of atemoya had no effect on the pharmacokinetics
of phenacetin, a CYP1A2 substrate, in rats. Meanwhile, preadministration of
fluvoxamine significantly extended the time needed for the elimination of
phenacetin, possibly due to the inhibition of CYP1A2. This suggests that the
intake of an excess amount of atemoya juice is necessary to cause a change in
the pharmacokinetics of phenacetin when the IC50 values for CYP1A2 inhibition by
atemoya and fluvoxamine are taken into account.
CONCLUSION: The results indicate that a daily intake of atemoya would not change
the pharmacokinetics of CYP1A2 substrates such as phenacetin as well as CYP2C9-
and CYP3A-substrate drugs. |
What is caused by biallelic variants in SPATA5L1? | Biallelic variants in SPATA5L1 lead to intellectual disability, spastic-dystonic cerebral palsy, epilepsy, and hearing loss. | Author information:
(1)Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine,
University of Maryland, Baltimore, MD 21201, USA.
(2)Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ
85016, USA; Departments of Child Health, Neurology, Cellular, and Molecular
Medicine and Program in Genetics, University of Arizona College of Medicine -
Phoenix, Phoenix, AZ 85004, USA.
(3)Department of Neuromuscular Disorders, Institute of Neurology, University
College London, Queen Square, WC1N 3BG London, UK.
(4)Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine,
Technical University of Munich, 81675 Munich, Germany; Institute of
Neurogenomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.
(5)CSIRO Health and Biosecurity, The Australian e-Health Research Centre,
Brisbane, QLD 4029, Australia.
(6)Pediatric Neuroradiology Division, Pediatric Radiology, Barrow Neurological
Institute, Phoenix Children's Hospital, Phoenix, AZ 85016, USA; University of
Arizona College of Medicine, Phoenix, AZ 85004, USA; Mayo Clinic, Scottsdale, AZ
85259, USA.
(7)Neurology Department, The Children's Hospital at Westmead, Westmead, NSW
2145, Australia.
(8)Department of Medical Genomics, Royal Prince Alfred Hospital, Sydney, NSW
2050, Australia.
(9)Center for Applied Genomics, Children's Hospital of Philadelphia,
Philadelphia, PA, USA.
(10)Department of Computer Science, City University of Hong Kong, Kowloon
999077, Hong Kong.
(11)Center for Applied Genomics, Children's Hospital of Philadelphia,
Philadelphia, PA 19104, USA; Center for Data Driven Discovery in Biomedicine,
Children's Hospital of Philadelphia, Philadelphia, PA 19146, USA.
(12)Department of Bone and Osteogenesis Imperfecta, Kennedy Krieger Institute,
Baltimore, MD 21205, USA.
(13)Center for Autism and Related Disorders, Kennedy Krieger Institute,
Baltimore, MD 21211, USA.
(14)Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA
02115, USA; Department of Neurology, Boston Children's Hospital, Boston, MA
02115, USA.
(15)University of Massachusetts Medical School - Baystate, Baystate Children's
Hospital, Springfield, MA 01107, USA.
(16)Department of Neurology and Developmental Medicine, Kennedy Krieger
Institute, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins
University School of Medicine, Baltimore, MD 21287, USA.
(17)Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine,
Technical University of Munich, 81675 Munich, Germany.
(18)Centre of Child and Adolescent Medicine, Department of Pediatric Neurology
and Metabolic Medicine, Heidelberg University Hospital, 69120 Heidelberg,
Germany.
(19)Department of Child Neurology and Metabolic Medicine, Center for Pediatric
and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld
430, 69120 Heidelberg, Germany.
(20)Department of Neurology and Developmental Medicine, Kennedy Krieger
Institute, Baltimore, MD 21205, USA.
(21)Dor Yeshorim, Committee for Prevention of Jewish Genetic Diseases, New York,
NY 11211, USA.
(22)Dor Yeshorim, Committee for Prevention of Jewish Genetic Diseases, Jerusalem
9054020, Israel.
(23)Department of Child Neurology, Justus-Liebig-University Giessen, 35392
Giessen, Germany.
(24)Department of Neurology, South Kazakhstan Medical Academy, Shymkent 160001,
Kazakhstan.
(25)Clinical Genetics, Royal Devon & Exeter NHS Foundation Trust, EX1 2ED
Exeter, UK.
(26)Clinical Pharmacology, William Harvey Research Institute, Charterhouse
Square, School of Medicine and Dentistry Queen Mary University of London, London
EC1M 6BQ, UK.
(27)Penn State Health Children's Hospital, Hershey, PA 17033, USA.
(28)Department of Clinical Neurosciences, John Van Geest Cambridge Centre for
Brain Repair, University of Cambridge School of Clinical Medicine, CB2 0PY
Cambridge, UK.
(29)Inonu University, Faculty of Medicine, Turgut Ozal Research Center,
Department of Paediatric Neurology, 44280 Malatya, Turkey.
(30)Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus,
35340 Izmir, Turkey; Department of Pediatric Neurology, Faculty of Medicine,
Dokuz Eylul University, 35340 Izmir, Turkey.
(31)Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus,
35340 Izmir, Turkey; Department of Medical Biology, Faculty of Medicine, Dokuz
Eylul University, 35220 Izmir, Turkey.
(32)Children's Hospital of Eastern Ontario Research Institute; Division of
Neurology, Department of Medicine, The Ottawa Hospital, and Brain and Mind
Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada.
(33)Università Cattolica Sacro Cuore, Facoltà di Medicina e Chirurgia,
Dipartimento Scienze della Vita e Sanità Pubblica, 00168 Roma, Italy; Fondazione
Policlinico A. Gemelli IRCCS, Sezione di Medicina Genomica, 00168 Roma, Italy.
(34)Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Naples, Italy.
(35)Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Naples, Italy;
Department of Precision Medicine, University of Campania "Luigi Vanvitelli,"
80138 Naples, Italy.
(36)Department of Neuropediatrics, Jena University Hospital, 07747 Jena,
Germany.
(37)Institute of Medical Genetics and Applied Genomics, University of Tübingen,
72076 Tuebingen, Germany.
(38)Institute of Systems Motor Science, University of Lübeck, 23538 Lübeck,
Germany.
(39)Department of Paediatric and Adolescent Medicine, St Joseph Hospital, 12101
Berlin, Germany.
(40)University Children's Hospital Oldenburg, Department of Neuropaediatric and
Metabolic Diseases, 26133 Oldenburg, Germany.
(41)Human Genetics, Faculty of Medicine and Health Sciences, University of
Oldenburg, 26129 Oldenburg, Germany; Junior Research Group, Genetics of
Childhood Brain Malformations, Faculty VI-School of Medicine and Health
Sciences, University of Oldenburg, 26129 Oldenburg, Germany.
(42)Human Genetics, Faculty of Medicine and Health Sciences, University of
Oldenburg, 26129 Oldenburg, Germany; Research Center Neurosensory Science,
University of Oldenburg, 26129 Oldenburg, Germany.
(43)Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino
Gesù, IRCCS, 00146 Rome, Italy.
(44)GeneDx, 207 Perry Parkway, Gaithersburg, MD 20877, USA.
(45)Unit of Child Neuropsichiatry, Department of Clinical and Surgical
Neurosciences and Rehabilitation, IRCCS Giannina Gaslini, Genoa 16147, Italy.
(46)Australian Regenerative Medicine Institute, Monash University, Clayton, VIC
3168, Australia.
(47)Pediatric Neurology and Muscular Diseases Unit, IRRCS Istituto Giannina
Gaslini, 16148 Genoa, Italy; Department of Neurosciences, Rehabilitation,
Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16142
Genoa, Italy.
(48)Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics,
Maternal and Child Health, University of Genoa, 16142 Genoa, Italy; Unit of
Medical Genetics, IRRCS Istituto Giannina Gaslini, 16147 Genoa, Italy.
(49)Departments of Pediatrics and Medicine, Columbia University, New York, NY
10032, USA.
(50)Department of Neurology, Cook Children's Medical Center, Fort Worth, TX
76104, USA; Department of Pediatrics, University of North Texas Health Science
Center, Fort Worth, TX 76107, USA.
(51)Robinson Research Institute, Faculty of Health and Medical Sciences,
University of Adelaide, Adelaide, SA 5006, Australia; Adelaide Medical School,
Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA
5000, Australia.
(52)Robinson Research Institute, Faculty of Health and Medical Sciences,
University of Adelaide, Adelaide, SA 5006, Australia; Adelaide Medical School,
Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA
5000, Australia; South Australian Health and Medical Research Institute,
Adelaide, SA 5000, Australia.
(53)Brain and Mitochondrial Research Group, Murdoch Children's Research
Institute, Melbourne Department of Paediatrics, University of Melbourne,
Melbourne, VIC 3052, Australia; Discipline of Child and Adolescent Health,
University of Sydney, Sydney, NSW 2006, Australia.
(54)Yale Center for Genome Analysis, Yale University, New Haven, CT 06520, USA;
Department of Genetics, Yale University School of Medicine, New Haven, CT 06510,
USA.
(55)Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine,
University of Maryland, Baltimore, MD 21201, USA; Department of Biochemistry and
Molecular Biology, School of Medicine, University of Maryland, Baltimore, MD
21201, USA.
(56)Ophthalmic Genetics and Visual Function Branch, National Eye Institute,
National Institutes of Health, Bethesda, MD 20892, USA.
(57)Department of Paediatrics, Monash University, Melbourne, VIC 3168,
Australia.
(58)Institute of Biochemistry, Friedrich-Alexander-Universität
Erlangen-Nürnberg, 91054 Erlangen, Germany.
(59)Department of Otolaryngology - Head and Neck Surgery, Tübingen Hearing
Research Centre, Eberhard Karls University Tübingen, 72076 Tübingen, Germany.
(60)Department of Genetics, Washington University School of Medicine, St. Louis,
MO 63110, USA.
(61)Institute of Medical Genetics and Applied Genomics, University of Tübingen,
72076 Tuebingen, Germany; Centre for Rare Diseases, University of Tübingen,
72074 Tuebingen, Germany.
(62)Department of Paediatrics, Adolescent Medicine and Neonatology, Munich
Clinic, Schwabing Hospital and Technical University of Munich, School of
Medicine, 80804 Munich, Germany.
(63)Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine,
University of Maryland, Baltimore, MD 21201, USA; Department of Biochemistry and
Molecular Biology, School of Medicine, University of Maryland, Baltimore, MD
21201, USA. Electronic address: [email protected].
(64)Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ
85016, USA; Departments of Child Health, Neurology, Cellular, and Molecular
Medicine and Program in Genetics, University of Arizona College of Medicine -
Phoenix, Phoenix, AZ 85004, USA. Electronic address: [email protected]. |
A combination of which two drugs was tested in the IMbrave150 trial? | IMbrave150 trial tested a combination of atezolizumab and bevacizumab for advanced hepatocellular carcinoma. | For over a decade, sorafenib remained the only systemic agent with proven
clinical efficacy for patients with advanced hepatocellular carcinoma (HCC).
Recent years have seen a proliferation of agents. In the first line, lenvatinib
was found to be non-inferior to sorafenib in terms of overall survival (OS),
with significantly better progression-free survival and objective response rate.
Meanwhile, encouraging efficacy signals were observed in phase I/II studies of
immune checkpoint inhibitors as monotherapy in HCC. Although subsequent phase
III trials failed to demonstrate statistically significant benefit in OS, other
clinically meaningful outcomes were observed, including long-term disease
control with a favorable toxicity profile. In addition, a synergistic response
has been postulated based on the interplay between antiangiogenic molecular
targeted agents and immunotherapy. On this basis, interest has turned toward
combination strategies of immunotherapy with these standard-of-care medications
in the hope of improving treatment efficacy for advanced HCC, while maintaining
tolerable safety profiles. Indeed, preliminary results from phase I studies of
lenvatinib plus pembrolizumab and atezolizumab plus bevacizumab have proved
favorable, prompting phase III investigations in the frontline setting, and for
atezolizumab plus bevacizumab, these positive findings have been substantiated
by recent reporting of phase III data from IMbrave150. In this review, we will
present the currently available data on combination therapy atezolizumab plus
bevacizumab in advanced HCC, and compare these findings to other promising
combination treatments, most notably that of lenvatinib plus pembrolizumab. Hepatocellular carcinoma remains a serious global disease. Its incidence is
increasing. Standard procedures have been developed for each stage. The
complexity of this disease shows that the selection of patients in stage 0/A for
different types of surgical treatment is very complicated. Treatment methods of
stage B, especially locoregional treatment represented by TACE (transarterial
chemoembolization or radioembolization of TARE), radiofrequency ablation and
others, move freely to lower and higher stages as adjunctive therapy. Lenvatinib
can replace TACE with equal efficacy in cases where locoregional treatment
cannot be used. Until 2016, the only systemic treatment option for stage C was
sorafenib. Lenvatinib became a second-line drug to show non-inferiority to
sorafenib in OS. Retrospective analyzes revealed that patients who responded to
the treatment with lenvatinib or sorafenib had a median survival of over 22
months. Sequential treatment with sorafenib and regorafenib in the RESOURCE
study with a median survival of more than 24 months was similar. Ramucirumab was
effective only in patients with high AFP levels. The study demonstrated the
importance of selecting patients according to prognostic factors (extrahepatic
spread and vascular invasion). Second-line cabozantinib has shown the same
benefit as regorafenib. In the second line, immunotherapy represented by anti
PD-1 antibodies nivolumab and pembrolizumab was used. Sequential administration
after sorafenib prolonged the median overall survival of about 22 months. We
currently have sorafenib and lenvatinib in the first line, regorafenib,
cabozantinib, ramucirumab (AFP 400 μg/L), pembrolizumab and nivolumab in
the second line. The possibilities of monotherapy have been exhausted. The
discovery of a synergistic effect of angiogenesis inhibitors, which convert a
cold tumor into a hot one and facilitate the efficacy of anti-PD-1 / anti-PDL-1
antibodies, has led to a highly effective combination therapy. In study
IMbrave150, the combination of atezolizumab and bevacizumab was successfully
used compared to sorafenib in the first-line treatment. Additional studies are
currently underway using other tyrosin kinase inhibitors - regorafenib,
lenvatinib and cabozantinib - in combination with nivolumab, ipilimumab and
pembrolizumab. This development of treatment at all stages evoked with renewed
urgency the need to find a suitable way to search for the early stages of HCC
and to create a more effective system for selecting patients for the most
appropriate treatment. Systemic therapy for hepatocellular carcinoma (HCC) has changed markedly since
the introduction of the molecular targeted agent sorafenib in 2007. Sorafenib
increased the available treatment options for patients with extrahepatic spread
and vascular invasion and improved survival in patients with advanced HCC;
however, various shortcomings such as low response rates and relatively high
toxicity (e.g., hand-foot skin reaction) prompted concerted efforts aimed at
developing new molecular targeted agents to provide more treatment options and
second-line agents for patients with disease progression or intolerance to
sorafenib. Despite many attempts to develop new drugs between 2007 and 2016, all
first-line and second-line clinical trials conducted during this period failed.
However, between 2017 and 2019, 4 drugs (lenvatinib as a first-line agent and
regorafenib, cabozantinib, and ramucirumab as second-line agents) emerged in
quick succession from clinical trials and became available for clinical use. In
addition, nivolumab and pembrolizumab were approved as second-line agents after
sorafenib. A recent phase III trial (IMbrave150) showed that combination
immunotherapy with atezolizumab plus bevacizumab increases overall survival
compared with sorafenib therapy; Food and Drug Agency already approved this
combination therapy, and worldwide approval is expected soon. This review
describes the recent advances in systemic therapy and the use of tyrosine kinase
inhibitors (sorafenib, lenvatinib, regorafenib, and cabozantinib), monoclonal
antibodies (ramucirumab and bevacizumab), and immune checkpoint inhibitors
(nivolumab, pembrolizumab, and atezolizumab) in elderly patients and the
similarity of their efficacy and safety profiles to those in the general
population. Introduction: The treatment of unresectable hepatocellular carcinoma (HCC) has
radically changed after the approval of the combination of atezolizumab plus
bevacizumab as first-line treatment. A strong preclinical rationale exists to
support the combination of bevacizumab, an anti-vascular endothelial growth
factor monoclonal antibody (mAb), and atezolizumab, an anti-programmed death
ligand 1 mAb. The efficacy of the combination was first assessed in the phase Ib
GO30140 study, and the combination was then proven superior to the prior
standard of care, sorafenib, in the phase III IMbrave150 trial.Areas covered:
This article focuses on the mechanism of action of atezolizumab and bevacizumab,
their synergistic action, and the two clinical trials leading to approval. We
also collected the body of post-hoc analyses and meta-analyses to help guide the
decision-making process in terms of patient selection and subsequent
treatments.Expert opinion: Atezolizumab plus bevacizumab are the current
standard of care for first-line treatment of unresectable or metastatic HCC and
treatment-naïve patient should be treated with the combination, unless
contraindications to the drugs. Since all the available agents for further lines
of treatment have been approved for sorafenib-pretreated patients, prospective
trials, post-hoc analyses, and real-world data assessing valid treatment
sequencing are strongly needed. AIM: A clinical trial (IMbrave150) indicated the efficacy and safety of
atezolizumab plus bevacizumab for patients with unresectable hepatocellular
carcinoma (HCC). In this study, we evaluated this therapeutic combination in a
real-world setting, with a focus on patients who did not meet the IMbrave150
eligibility criteria.
METHODS: In this multicenter study, patients with unresectable HCC treated with
atezolizumab plus bevacizumab between October 2020 and May 2021 were screened.
In patients who did not meet IMbrave150 eligibility criteria, treatment
responses and safety at 6 and 12 weeks were evaluated.
RESULTS: Atezolizumab plus bevacizumab was initiated in 64 patients, including
46 patients (71.9%) who did not meet IMbrave150 eligibility criteria. Most of
these patients had a history of systemic therapy (44/46). The objective response
rate and disease control rate observed using Response Evaluation Criteria in
Solid Tumors 1.1 were 5.2% and 82.8% at 6 weeks and 10.0% and 84.0% at 12 weeks,
respectively; these rates were similar between patients who met and did not meet
the IMbrave150 criteria. Ten patients experienced progressive disease (PD) at
6 weeks. Portal vein tumor thrombosis was significantly associated with PD
(p = 0.039); none of the 15 patients with hepatitis B virus-related HCC
experienced PD (p = 0.050). The most common adverse events of grade 3 or higher
were aspartate aminotransferase elevation (n = 8, 13.8%) and the safety profile
was similar between patients who met and did not meet the IMbrave150 criteria.
CONCLUSION: Most patients treated with atezolizumab plus bevacizumab did not
meet the IMbrave150 criteria; however, the combination therapy showed good
safety and efficacy at the early treatment phase. In light of positive efficacy and safety findings from the IMbrave150 trial of
atezolizumab plus bevacizumab, this novel combination has become the preferred
first-line standard of care for patients with unresectable hepatocellular
carcinoma (HCC). Several additional trials are ongoing that combine an immune
checkpoint inhibitor with another agent such as a multiple kinase inhibitor or
antiangiogenic agent. Therefore, the range of first-line treatment options for
unresectable HCC is likely to increase, and healthcare providers need succinct
information about the use of such combinations, including their efficacy and key
aspects of their safety profiles. Here, we review efficacy and safety data on
combination immunotherapies and offer guidance on monitoring and managing
adverse events, especially those associated with atezolizumab plus bevacizumab.
Because of their underlying liver disease and high likelihood of portal
hypertension, patients with unresectable HCC are at particular risk of
gastrointestinal bleeding, and this risk may be exacerbated by treatments that
include antiangiogenic agents. Healthcare providers also need to be alert to the
risks of proteinuria and hypertension, colitis, hepatitis, and reactivation of
hepatitis B or C virus infection. They should also be aware of the possibility
of rarer but potentially life-threatening adverse events such as pneumonitis and
cardiovascular events. Awareness of the risks associated with these therapies
and knowledge of adverse event monitoring and management will become
increasingly important as the therapeutic range broadens in unresectable HCC. Portal vein involvement is considered one of the most fearful complications of
hepatocellular carcinoma (HCC). Portal vein tumor thrombosis (PVTT) is
associated with aggressive tumor biology (high grade), high tumor burden (number
and size of lesions), high levels of serum markers (AFP), poor liver function
(deranged LFT), and poor performance status of patients. The Barcelona Clinic
Liver Cancer staging system places HCC patients with PVTT in advanced stage
(BCLC Stage-C). This group contains a fairly heterogeneous patient population,
previously considered candidates for palliative systemic therapy with sorafenib.
However, this provided modest overall survival (OS) benefit. The results of a
recent Phase III (IMbrave150) trial favor the combination of atezolizumab and
bevacizumab over sorafenib as a standard of care in advanced unresectable HCC.
While only lenvatinib proved to be non-inferior against sorafenib in a phase III
(REFLECT trial), regorafenib (RESORCE trial), ramucirumab (REACH-2), and
cabozantinib (CELESTIAL) have been approved second-line therapy in phase III
clinical trials. Recently, the data on the prospect of other modalities in the
management of HCC with PVTT is mounting with favorable results. Targeting
multiple pathways in the HCC cascade using a combination of drugs and other
modalities such as RT, TACE, TARE, and HAIC appear effective for systemic and
loco-regional control. The quest for the ideal combination therapy and the
sequence set is still widely uswered and prospective trials are lacking. With
the armament of available therapeutic options and the advances and refinements
in the delivery system, down-staging patients to make them eligible for curative
resection has been reported. In a rapidly evolving treatment landscape,
performing surgery when appropriate, in the form of LR and even LT to achieve
cure does not seem farfetched. Likewise, adjuvant therapy and prompt management
of the recurrences holds the key to prolong OS and DFS. This review discusses
the management options of HCC patients with PVTT. Atezolizumab plus bevacizumab combination therapy was approved worldwide for use
in 2020. A 30% objective response rate with 8% complete response (CR) was
achieved in a phase 3 IMbrave150 trial. Here, the change in the treatment
strategy for hepatocellular carcinoma (HCC) using atezolizumab plus bevacizumab
combination therapy is reviewed. The phase 3 IMbrave150 clinical trial was
successful because of the direct antitumor effect of bevacizumab, which shifted
the suppressive immune microenvironment to a responsive immune microenvironment,
in addition to its synergistic effects when combined with atezolizumab. The
analysis of CR cases was effective in patients with poor conditions,
particularly tumor invasion in the main portal trunk (Vp4), making the
combination therapy a breakthrough for HCC treatment. The response rate of the
combination therapy was 44% against intermediate-stage HCC. Such a strong
tumor-reduction effect paves the way for curative conversion (ABC conversion)
therapy and, therefore, treatment strategies for intermediate-stage HCC may
undergo a significant shift in the future. As these treatment strategies are
effective in maintaining liver function, even in elderly patients, the
transition frequency to second-line treatments could also be improved. These
strategies may be effective against nonalcoholic steatohepatitis-related
hepatocellular carcinoma and WNT/β-catenin mutations to a certain degree. INTRODUCTION: The treatment algorithm of advanced hepatocellular carcinoma (HCC)
has evolved since the introduction of immunotherapy. The IMbrave150 trial set
atezolizumab-bevacizumab as a new standard-of-care first-line treatment for
unresectable HCC patients. However, for patients with intermediate or advanced
stage with portal vein thrombosis but without distant metastases, 90Yttrium
transarterial radioembolization (90Y-TARE) is considered the treatment of
choice.
AREAS COVERED: We discuss the main evidence regarding the use of 90Y-TARE in
HCC, the recent progress of immunotherapy in this tumor, and the preclinical
rationale of combining VEGF blockade with the other two treatment strategies.
EXPERT OPINION: HCC has an extremely heterogeneous tumor immune
microenvironment. This may explain the inconsistent outcomes obtained with
immune-checkpoint inhibitors. The identification of patients who could benefit
most from immunotherapy is crucial; however, reliable markers of response are
lacking. Radiation therapy and VEGF inhibition have an established synergism
with immunotherapy, mainly linked to enhanced antigen presentation and reduced
immunosuppressive immune infiltrate. Combining an immune-checkpoint inhibitor
with VEGF blockade and 90Y-TARE might hence overcome primary resistances
observed when each of these treatments is administerd alone. |
Is ALS a heritable disease? | Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disorder of the motor system. The etiology is still unknown and the pathogenesis remains unclear. ALS is familial in the 10% of cases with a Mendelian pattern of inheritance. | Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. The majority
of cases are sporadic (sALS), while the most common inherited form is due to
C9orf72 mutation (C9ALS). A high burden of inclusion pathology is seen in glia
(including oligodendrocytes) in ALS, especially in C9ALS. Myelin basic protein
(MBP) messenger RNA (mRNA) must be transported to oligodendrocyte processes for
myelination, a possible vulnerability for normal function. TDP43 is found in
pathological inclusions in ALS and is a component of mRNA transport granules.
Thus, TDP43 aggregation could lead to MBP loss. Additionally, the hexanucleotide
expansion of mutant C9ALS binds hnRNPA2/B1, a protein essential for mRNA
transport, causing potential further impairment of hnRNPA2/B1 function, and thus
myelination. Using immunohistochemistry for p62 and TDP43 in human post-mortem
tissue, we found a high burden of glial inclusions in the prefrontal cortex,
precentral gyrus, and spinal cord in ALS, which was greater in C9ALS than in
sALS cases. Double staining demonstrated that the majority of these inclusions
were in oligodendrocytes. Using immunoblotting, we demonstrated reduced MBP
protein levels relative to PLP (a myelin component that relies on protein not
mRNA transport) and neurofilament protein (an axonal marker) in the spinal cord.
This MBP loss was disproportionate to the level of PLP and axonal loss,
suggesting that impaired mRNA transport may be partly responsible. Finally, we
show that in C9ALS cases, the level of oligodendroglial inclusions correlates
inversely with levels of hnRNPA2/B1 and the number of oligodendrocyte precursor
cells. We conclude that there is considerable oligodendrocyte pathology in ALS,
which at least partially reflects impairment of mRNA transport. © 2020 The
Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf
of Pathological Society of Great Britain and Ireland. Amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative
disease involving the upper and lower motor neurons of the spinal cord,
brainstem, and cerebral cortex. At least 30 genes have been implicated in
familial ALS (fALS) and sporadic ALS (sALS). Kaneb et al. (2015) first carried
out a large-scale sequencing study in ALS patients and identified two
loss-of-function (LOF) variants in the GLE1 gene. The LOF mutation-induced
disruption of RNA metabolism through the haploinsufficiency mechanism is
implicated in ALS pathogenesis. A total of 628 ALS patients and 522 individuals
without neurodegenerative disorders were enrolled in this study to explore the
GLE1 gene contribution to ALS in the Chinese population. All 16 exons and the
flanking intron of GLE1 were screened by Sanger sequencing. In total, we
identified seven rare GLE1 coding variants, including one novel nonsense
mutation and six rare missense mutations in 628 ALS patients. The frequency of
GLE1 LOF mutations was 0.16% (1/628) among Chinese sALS patients, implying that
it is an uncommon genetic determit of ALS in Chinese patients. Additionally,
the rare missense variants in the hCG1-binding domain of GLE1 impairing the
distribution of the hGle1B isoform at the nuclear pore complex (NPC) region may
be involved in the pathogenesis of ALS. |
What is ARNIL? | Long noncoding RNA (lncRNA) antisense noncoding RNA in the INK4 locus (ANRIL) is involved in several human cancers. | Long noncoding RNA (lncRNA) antisense noncoding RNA in the INK4 locus (ANRIL) is
involved in several human cancers. However, the role of ANRIL in renal cell
carcinoma (RCC) remains unclear. This study aimed to explore whether, and how,
ANRIL affects the progression of RCC. First, the expression of ANRIL in clinical
tumor tissues and four kinds of RCC cell lines was evaluated. After
transfection, cell viability, colony number, apoptosis, migration, and invasion
were assessed. The expression of proteins related to apoptosis,
epithelial-to-mesenchymal transition (EMT), and the β-catenin signaling pathway
was then assessed. In addition, the effect of IWR-endo (β-catenin inhibitor) on
cell viability, migration, and invasion, as well as β-catenin expression, was
also evaluated. The results showed that ANRIL was highly expressed in RCC
tissues and RCC cell lines. ANRIL significantly promoted cell proliferation,
migration, invasion, and EMT but inhibited cell apoptosis. Additionally, the
expression levels of β-catenin, Ki-67, glycogen synthase kinase 3β (GSK-3β),
phosphorylated GSK-3β, T-cell transcription factor 4 (TCF-4), and leukemia
enhancer factor 1 (LEF-1) were all markedly upregulated by ANRIL. The effect of
ARNIL silencing was opposite to that of ANRIL overexpression. The effect of
ARNIL on proliferation, migration, and invasion of RCC cells was found to be
reversed by IWR-endo. In conclusion, ANRIL, which is highly expressed in RCC,
acted as a carcinogen in RCC cells through the activation of the β-catenin
pathway. |
What is the indication of CPX-351? | CPX-351 has been approved by the US FDA and the EMA for the treatment of adults with newly diagnosed therapy-related acute myeloid leukemia or acute myeloid leukemia with myelodysplasia-related changes. | BACKGROUND: CPX-351 (United States: Vyxeos®; Europe: Vyxeos® Liposomal), a
dual-drug liposomal encapsulation of daunorubicin and cytarabine in a
synergistic 1:5 molar ratio, is approved by the US FDA and the EMA for the
treatment of adults with newly diagnosed therapy-related acute myeloid leukemia
or acute myeloid leukemia with myelodysplasia-related changes. In a pivotal
phase 3 study that evaluated 309 patients aged 60 to 75 years with newly
diagnosed high-risk/secondary acute myeloid leukemia, CPX-351 significantly
improved median overall survival versus conventional 7 + 3 chemotherapy
(cytarabine continuous infusion for 7 days plus daunorubicin for 3 days), with a
comparable safety profile. A Quality-adjusted Time Without Symptoms of disease
or Toxicity (Q-TWiST) analysis of the phase 3 study was performed to compare
survival quality between patients receiving CPX-351 versus conventional 7 + 3
after 5 years of follow-up.
METHODS: Patients were randomized 1:1 between December 20, 2012 and November 11,
2014 to receive induction with CPX-351 or 7 + 3. Survival time for each patient
was partitioned into 3 health states: TOX (time with any grade 3 or 4 toxicity
or prior to remission), TWiST (time in remission without relapse or grade 3 or 4
toxicity), and REL (time after relapse). Within each treatment arm, Q-TWiST was
calculated by adding the mean time spent in each health state weighted by its
respective quality-of-life, represented by health utility. The relative Q-TWiST
gain, calculated as the difference in Q-TWiST between treatment arms divided by
the mean survival of the 7 + 3 control arm, was determined in order to evaluate
results in the context of other Q-TWiST analyses.
RESULTS: The relative Q-TWiST gain with CPX-351 versus 7 + 3 was 53.6% in the
base case scenario and 39.8% among responding patients. Across various
sensitivity analyses, the relative Q-TWiST gains for CPX-351 ranged from 48.0 to
57.6%, remaining well above the standard clinically important difference
threshold of 15% for oncology.
CONCLUSIONS: This post hoc analysis demonstrates that CPX-351 improved
quality-adjusted survival, further supporting the clinical benefit in patients
with newly diagnosed high-risk/secondary acute myeloid leukemia. Trial
registration This trial was registered on September 28, 2012 at
www.clinicaltrials.gov as NCT01696084 (
https://clinicaltrials.gov/ct2/show/NCT01696084 ) and is complete. |
List signs of patients with biallelic variants in KARS1 | KARS1-associated signs are autism, hyperactive behavior, pontine hypoplasia, and cerebellar atrophy with prevalent vermian involvement. | |
Which substance use is associated with Brodifacoum poisoning? | Brodifacoum poisoning was linked to marijuana use. | We report the case of a 17-year-old boy with a significant history of drug and
alcohol abuse, which included smoking marijuana mixed with brodifacoum. As a
consequence, the patient developed a prolonged coagulopathy that persisted for
more than 1 year. To our knowledge, this is the first case reported in the
literature in which super-warfarin intoxication has been associated with
marijuana smoking. This report should increase the awareness of pathologists and
clinicians when examining a patient with a history of drug abuse who exhibits
persistent vitamin K1-dependent coagulopathy. Synthetic marijuana is a dangerous substance due to its potency, ever-changing
composition, and unpredictable side effects. Recently, brodifacoum-contaminated
synthetic marijuana has led to multiple deaths and morbidity throughout the USA
from severe coagulopathy associated with use of this strain of the drug
(brodifacoum is a rodenticide and potent Vitamin K antagonist/anticoagulant). We
describe the clinical and radiologic findings in two patients who were diagnosed
with, and treated for, ingestion of this new strain of synthetic marijuana. The
radiologic manifestations were most notable for hemorrhagic pyelitis/ureteritis.
Both patients required hospitalization with Vitamin K supplementation. The
radiologic and clinical pictures in these patients are important for
radiologists to recognize in order to help guide appropriate patient management. BACKGROUND: In March and April 2018, more than 150 patients presented to
hospitals in Illinois with coagulopathy and bleeding diathesis. Area physicians
and public health organizations identified an association between coagulopathy
and synthetic cannabinoid use. Preliminary tests of patient serum samples and
drug samples revealed that brodifacoum, an anticoagulant, was the likely
adulterant.
METHODS: We reviewed physician-reported data from patients admitted to Saint
Francis Medical Center in Peoria, Illinois, between March 28 and April 21, 2018,
and included in a case series adult patients who met the criteria used to
diagnose synthetic cannabinoid-associated coagulopathy. A confirmatory
anticoagulant poisoning panel was ordered at the discretion of the treating
physician.
RESULTS: A total of 34 patients were identified as having synthetic
cannabinoid-associated coagulopathy during 45 hospitalizations. Confirmatory
anticoagulant testing was performed in 15 of the 34 patients, and superwarfarin
poisoning was confirmed in the 15 patients tested. Anticoagulant tests were
positive for brodifacoum in 15 patients (100%), difenacoum in 5 (33%),
bromadiolone in 2 (13%), and warfarin in 1 (7%). Common symptoms at presentation
included gross hematuria in 19 patients (56%) and abdominal pain in 16 (47%).
Computed tomography was performed to evaluate abdominal pain and revealed renal
abnormalities in 12 patients. Vitamin K1 (phytonadione) was administered orally
in all 34 patients and was also administered intravenously in 23 (68%). Red-cell
transfusion was performed in 5 patients (15%), and fresh-frozen plasma infusion
in 19 (56%). Four-factor prothrombin complex concentrate was used in 1 patient.
One patient died from complications of spontaneous intracranial hemorrhage.
CONCLUSIONS: Our data indicate that superwarfarin adulterants of synthetic
cannabinoids can lead to clinically significant coagulopathy. In our series, in
most of the cases in which the patient presented with bleeding diathesis,
symptoms were controlled with the use of vitamin K1 replacement therapy. The
specific synthetic cannabinoid compounds are not known. Recent evidence demonstrates a rising epidemic of unintentional brodifacoum
poisoning associated with synthetic cannabinoid use. Synthetic cannabinoid use
is on the rise because of its inexpensiveness as well as difficulty to screen
and regulate. We present a rare case of severe coagulopathy and cardiac arrest
secondary to synthetic cannabinoid use complicated by brodifacoum toxicity. INTRODUCTION: Recent outbreaks of brodifacoum-induced coagulopathy resulting
from the use of synthetic cannabinoids represents a growing public health
concern. Brodifacoum is a commonly used and commercially available rodenticide
that has anticoagulant properties. As new, unregulated synthetic cannabinoids
enter the market, the potential for further outbreaks continues to rise.
CASE PRESENTATION: We report a case of severe bleeding secondary to inhalation
of synthetic cannabinoids contaminated with brodifacoum. The patient had been
evaluated for several months of ongoing, unexplained vaginal bleeding and
developed hematemesis and rectal bleeding 2 weeks after her last reported use.
DISCUSSION: There have been previous reports of hemorrhage after exposure to
synthetic marijuana in rare cases, including an outbreak of severe bleeding and
reported synthetic marijuana use in the Midwestern region of the United States
in 2018.
CONCLUSION: While hemorrhaging after exposure to synthetic cannabinoids has been
reported previously, we use this case to increase awareness of the potentially
deadly exposures to brodifacoum from synthetic cannabinoids use in Wisconsin. By
increasing awareness, emergency department physicians and state agencies can
collaborate more effectively when responding in these cases. A 50-year-old man was admitted to the emergency department with abrupt massive
epistaxis. An accurate anamnesis and physical evaluation could not reveal any
other anomalies, while coagulation tests showed potentially life threatening
prolonged prothrombin time, with activated partial thromboplastin and thrombin
time, with fibrinogen and antithrombin III within limits. Despite the prompt
pharmacological and compressive local treatment, bleeding continued and the
patient was therefore hospitalized. Highly specific coagulation and
toxicological testing-among others high-performance liquid chromatography
assessment on plasma-were performed, leading to the unexpected identification of
brodifacoum. Police and criminal justice authorities revealed the source of
exposure to brodifacoum after several months of investigation, residing in his
everyday life. Brodifacoum is a long-lasting anticoagulant, acting as a vitamin
K antagonist, and belongs to the family of superwarfarins. Brodifacoum use is
authorized as rodenticide in many countries worldwide, but has been reported as
cause of severe coagulopathies in humans, both intentional or involuntary, even
consumed as a contamit of herbal drugs, such as cannabis. The original
contribution of this case to the knowledges of human brodifacoum intoxication
resides in the multidisciplinary approach and the collaborative interplay of
clinical and toxicology experts as well as judicial authorities. |
What is Alphafold? | AlphaFold is a novel machine learning approach that incorporates physical and biological knowledge about protein structure, leveraging multi-sequence alignments, into the design of the deep learning algorithm. | Proteins are essential to life, and understanding their structure can facilitate
a mechanistic understanding of their function. Through an enormous experimental
effort1-4, the structures of around 100,000 unique proteins have been
determined5, but this represents a small fraction of the billions of known
protein sequences6,7. Structural coverage is bottlenecked by the months to years
of painstaking effort required to determine a single protein structure. Accurate
computational approaches are needed to address this gap and to enable
large-scale structural bioinformatics. Predicting the three-dimensional
structure that a protein will adopt based solely on its amino acid sequence-the
structure prediction component of the 'protein folding problem'8-has been an
important open research problem for more than 50 years9. Despite recent
progress10-14, existing methods fall far short of atomic accuracy, especially
when no homologous structure is available. Here we provide the first
computational method that can regularly predict protein structures with atomic
accuracy even in cases in which no similar structure is known. We validated an
entirely redesigned version of our neural network-based model, AlphaFold, in the
challenging 14th Critical Assessment of protein Structure Prediction (CASP14)15,
demonstrating accuracy competitive with experimental structures in a majority of
cases and greatly outperforming other methods. Underpinning the latest version
of AlphaFold is a novel machine learning approach that incorporates physical and
biological knowledge about protein structure, leveraging multi-sequence
alignments, into the design of the deep learning algorithm. |
List diseases that are repeat expansion disorders (REDs). | The expansion of Short tandem repeats underlies the pathogenesis of multiple neurological disorders, including Huntington's disease, amyotrophic lateral sclerosis, and frontotemporal dementia, fragile X-associated tremor/ataxia syndrome, and myotonic dystrophies, known as repeat expansion disorders (REDs). | Huntington's disease (HD) is an autosomal domit neurodegenerative disorder
caused by an expanded (CAG)n repeat on the huntingtin gene. It is characterised
by motor, psychiatric and cognitive disturbances. Diagnosis can be confirmed by
direct genetic testing, which is highly sensitive and specific and is now
considered definitive. This study focused on 21 patients presenting with a
clinical phenotype showing strong similarity to HD, but who do not have an
expanded CAG in the huntingtin gene. However, other possible diagnoses could be
evoked for most of them. Seven patients (3.5% of our cohort) could be considered
as phenocopies of HD with no alternative diagnosis. Samples were screened for
other triplet repeat diseases with similar presentation (DRPLA, SCA-1, SCA-2,
SCA-3, SCA-6, and SCA-7) and were all negative. The repeat expansion detection
technique (RED) was used to detect uncloned CAG repeat expansions and samples
were also analysed by polymerase chain reaction for expansions of the
polymorphic CAG-ERDA-1 and CTG18.1 trinucleotide repeats. RED expansion (>40
repeats) was detected in only one patient. The results suggest that unstable
CAG/CTG repeat expansions corresponding to known or unknown sequences are not
involved in the aetiology of HD-like disorders. It is hypothesised that some of
these phenocopies could correspond to mutations in other unidentified genes with
other unstable repeats (different from CAG) or in unknown genes with other
mutations. Expansion of a tandem repeat tract is responsible for the Repeat Expansion
diseases, a group of more than 20 human genetic disorders that includes those
like Fragile X (FX) syndrome that result from repeat expansion in the FMR1 gene.
We have previously shown that the ATM and Rad3-related (ATR) checkpoint kinase
protects the genome against one type of repeat expansion in a FX premutation
mouse model. By crossing the FX premutation mice to Ataxia
Telangiectasia-Mutated (Atm) mutant mice, we show here that ATM also prevents
repeat expansion. However, our data suggest that the ATM-sensitive mechanism is
different from the ATR-sensitive one. Specifically, the effect of the ATM
deficiency is more marked when the premutation allele is paternally transmitted
and expansions occur more frequently in male offspring regardless of the Atm
genotype of the offspring. The gender effect is most consistent with a repair
event occurring in the early embryo that is more efficient in females, perhaps
as a result of the action of an X-linked DNA repair gene. Our data thus support
the hypothesis that two different mechanisms of FX repeat expansion exist, an
ATR-sensitive mechanism seen on maternal transmission and an ATM-sensitive
mechanism that shows a male expansion bias. The fragile X-related disorders (FXDs) are members of the group of diseases
known as the repeat expansion diseases. The FXDs result from expansion of an
unstable CGG/CCG repeat tract in the 5' UTR of the FMR1 gene. Contractions are
also seen, albeit at lower frequency. We have previously shown that ERCC6/CSB
plays an auxiliary role in promoting germ line and somatic expansions in a mouse
model of the FXDs. However, work in model systems of other repeat expansion
diseases has suggested that CSB may protect against expansions by promoting
contractions. Since FXD mice normally have such a high expansion frequency, it
is possible that such a protective effect would have been masked. We thus
examined the effect of the loss of CSB in an Msh2(+/-) background where the germ
line expansion frequency is reduced and in an Msh2(-/-) background where
expansions do not occur, but contractions do. Our data show that in addition to
promoting repeat expansion, CSB does in fact protect the genome from germ line
expansions in the FXD mouse model. However, it likely does so not by promoting
contractions but by promoting an error-free process that preserves the parental
allele. The Fragile X-related disorders (FXDs) are members of the Repeat Expansion
Diseases, a group of human genetic conditions resulting from expansion of a
specific tandem repeat. The FXDs result from expansion of a CGG/CCG repeat tract
in the 5' UTR of the FMR1 gene. While expansion in a FXD mouse model is known to
require some mismatch repair (MMR) proteins, our previous work and work in mouse
models of another Repeat Expansion Disease show that early events in the base
excision repair (BER) pathway play a role in the expansion process. One model
for repeat expansion proposes that a non-canonical MMR process makes use of the
nicks generated early in BER to load the MMR machinery that then generates
expansions. However, we show here that heterozygosity for a Y265C mutation in
Polβ, a key polymerase in the BER pathway, is enough to significantly reduce
both the number of expansions seen in paternal gametes and the extent of somatic
expansion in some tissues of the FXD mouse. These data suggest that events in
the BER pathway downstream of the generation of nicks are also important for
repeat expansion. Somewhat surprisingly, while the number of expansions is
smaller, the average size of the residual expansions is larger than that seen in
WT animals. This may have interesting implications for the mechanism by which
BER generates expansions. Fragile X-associated disorders are Repeat Expansion Diseases that result from
expansion of a CGG/CCG-repeat in the FMR1 gene. Contractions of the repeat tract
also occur, albeit at lower frequency. However, these contractions can
potentially modulate disease symptoms or generate an allele with repeat numbers
in the normal range. Little is known about the expansion mechanism and even less
about contractions. We have previously demonstrated that the mismatch repair
(MMR) protein MSH2 is required for expansions in a mouse model of these
disorders. Here, we show that MSH3, the MSH2-binding partner in the MutSβ
complex, is required for 98% of germ line expansions and all somatic expansions
in this model. In addition, we provide evidence for two different contraction
mechanisms that operate in the mouse model, a MutSβ-independent one that
generates small contractions and a MutSβ-dependent one that generates larger
ones. We also show that MutSβ complexes formed with the repeats have altered
kinetics of ATP hydrolysis relative to complexes with bona fide MMR substrates
and that MutSβ increases the stability of the CCG-hairpins at physiological
temperatures. These data may have important implications for our understanding
of the mechanism(s) of repeat instability and for the role of MMR proteins in
this process. Expansion of a CGG-repeat tract in the 5' untranslated region of the FMR1 gene
causes the fragile X-related disorders (FXDs; aka the FMR1 disorders). The
expansion mechanism is likely shared by the 35+ other diseases resulting from
expansion of a disease-specific microsatellite, but many steps in this process
are unknown. We have shown previously that expansion is dependent upon
functional mismatch repair proteins, including an absolute requirement for
MutLγ, one of the three MutL heterodimeric complexes found in mammalian cells.
We demonstrate here that both MutLα and MutLβ, the two other MutL complexes
present in mammalian cells, are also required for most, if not all, expansions
in a mouse embryonic stem cell model of the FXDs. A role for MutLα and MutLβ is
consistent with human GWA studies implicating these complexes as modifiers of
expansion risk in other Repeat Expansion Diseases. The requirement for all three
complexes suggests a novel model in which these complexes co-operate to generate
expansions. It also suggests that the PMS1 subunit of MutLβ may be a reasonable
therapeutic target in those diseases in which somatic expansion is an important
disease modifier. The Fragile-X related disorders (FXDs) are Repeat Expansion Diseases (REDs) that
result from expansion of a CGG-repeat tract located at the 5' end of the FMR1
gene. While expansion affects transmission risk and can also affect disease risk
and severity, the underlying molecular mechanism responsible is unknown. Despite
the fact that expanded alleles can be seen both in humans and mouse models in
vivo, existing patient-derived cells do not show significant repeat expansions
even after extended periods in culture. In order to develop a good tissue
culture model for studying expansions we tested whether mouse embryonic stem
cells (mESCs) carrying an expanded CGG repeat tract in the endogenous Fmr1 gene
are permissive for expansion. We show here that these mESCs have a very high
frequency of expansion that allows changes in the repeat number to be seen
within a matter of days. CRISPR-Cas9 gene editing of these cells suggests that
this may be due in part to the fact that non-homologous end-joining (NHEJ),
which is able to protect against expansions in some cell types, is not effective
in mESCs. CRISPR-Cas9 gene editing also shows that these expansions are
MSH2-dependent, consistent with those seen in vivo. While comparable human
Genome Wide Association (GWA) studies are not available for the FXDs, such
studies have implicated MSH2 in expansion in other REDs. The shared unusual
requirement for MSH2 for this type of microsatellite instability suggests that
this new cell-based system is relevant for understanding the mechanism
responsible for this peculiar type of mutation in humans. The high frequency of
expansions and the ease of gene editing these cells should expedite the
identification of factors that affect expansion risk. Additionally, we found
that, as with cells from human premutation (PM) carriers, these cell lines have
elevated mitochondrial copy numbers and Fmr1 hyperexpression, that we show here
is O2-sensitive. Thus, this new stem cell model should facilitate studies of
both repeat expansion and the consequences of expansion during early embryonic
development. Fragile X-related disorders (FXDs), also known as FMR1 disorders, are examples
of repeat expansion diseases (REDs), clinical conditions that arise from an
increase in the number of repeats in a disease-specific microsatellite. In the
case of FXDs, the repeat unit is CGG/CCG and the repeat tract is located in the
5' UTR of the X-linked FMR1 gene. Expansion can result in neurodegeneration,
ovarian dysfunction, or intellectual disability depending on the number of
repeats in the expanded allele. A growing body of evidence suggests that the
mutational mechanisms responsible for many REDs share several common features.
It is also increasingly apparent that in some of these diseases the pathologic
consequences of expansion may arise in similar ways. It has long been known that
many of the disease-associated repeats form unusual DNA and RNA structures. This
review will focus on what is known about these structures, the proteins with
which they interact, and how they may be related to the causative mutation and
disease pathology in the FMR1 disorders. |
What is bb21217? | BB21217 is a chimeric antigen receptor (CAR)-modified T-cell therapy used to target B-cell maturation antigen (BCMA) in the treatment of multiple myeloma. | Despite considerable advances in the treatment of multiple myeloma (MM) in the
last decade, a substantial proportion of patients do not respond to current
therapies or have a short duration of response. Furthermore, these treatments
can have notable morbidity and are not uniformly tolerated in all patients. As
there is no cure for MM, patients eventually become resistant to therapies,
leading to development of relapsed/refractory MM. Therefore, an unmet need
exists for MM treatments with novel mechanisms of action that can provide
durable responses, evade resistance to prior therapies, and/or are better
tolerated. B-cell maturation antigen (BCMA) is preferentially expressed by
mature B lymphocytes, and its overexpression and activation are associated with
MM in preclinical models and humans, supporting its potential utility as a
therapeutic target for MM. Moreover, the use of BCMA as a biomarker for MM is
supported by its prognostic value, correlation with clinical status, and its
ability to be used in traditionally difficult-to-monitor patient populations.
Here, we review three common treatment modalities used to target BCMA in the
treatment of MM: bispecific antibody constructs, antibody-drug conjugates, and
chimeric antigen receptor (CAR)-modified T-cell therapy. We provide an overview
of preliminary clinical data from trials using these therapies, including the
BiTE® (bispecific T-cell engager) immuno-oncology therapy AMG 420, the
antibody-drug conjugate GSK2857916, and several CAR T-cell therapeutic agents
including bb2121, NIH CAR-BCMA, and LCAR-B38M. Notable antimyeloma activity and
high minimal residual disease negativity rates have been observed with several
of these treatments. These clinical data outline the potential for BCMA-targeted
therapies to improve the treatment landscape for MM. Importantly, clinical
results to date suggest that these therapies may hold promise for deep and
durable responses and support further investigation in earlier lines of
treatment, including newly diagnosed MM. BACKGROUND: CPX-351 (United States: Vyxeos®; Europe: Vyxeos® Liposomal), a
dual-drug liposomal encapsulation of daunorubicin and cytarabine in a
synergistic 1:5 molar ratio, is approved by the US FDA and the EMA for the
treatment of adults with newly diagnosed therapy-related acute myeloid leukemia
or acute myeloid leukemia with myelodysplasia-related changes. In a pivotal
phase 3 study that evaluated 309 patients aged 60 to 75 years with newly
diagnosed high-risk/secondary acute myeloid leukemia, CPX-351 significantly
improved median overall survival versus conventional 7 + 3 chemotherapy
(cytarabine continuous infusion for 7 days plus daunorubicin for 3 days), with a
comparable safety profile. A Quality-adjusted Time Without Symptoms of disease
or Toxicity (Q-TWiST) analysis of the phase 3 study was performed to compare
survival quality between patients receiving CPX-351 versus conventional 7 + 3
after 5 years of follow-up.
METHODS: Patients were randomized 1:1 between December 20, 2012 and November 11,
2014 to receive induction with CPX-351 or 7 + 3. Survival time for each patient
was partitioned into 3 health states: TOX (time with any grade 3 or 4 toxicity
or prior to remission), TWiST (time in remission without relapse or grade 3 or 4
toxicity), and REL (time after relapse). Within each treatment arm, Q-TWiST was
calculated by adding the mean time spent in each health state weighted by its
respective quality-of-life, represented by health utility. The relative Q-TWiST
gain, calculated as the difference in Q-TWiST between treatment arms divided by
the mean survival of the 7 + 3 control arm, was determined in order to evaluate
results in the context of other Q-TWiST analyses.
RESULTS: The relative Q-TWiST gain with CPX-351 versus 7 + 3 was 53.6% in the
base case scenario and 39.8% among responding patients. Across various
sensitivity analyses, the relative Q-TWiST gains for CPX-351 ranged from 48.0 to
57.6%, remaining well above the standard clinically important difference
threshold of 15% for oncology.
CONCLUSIONS: This post hoc analysis demonstrates that CPX-351 improved
quality-adjusted survival, further supporting the clinical benefit in patients
with newly diagnosed high-risk/secondary acute myeloid leukemia. Trial
registration This trial was registered on September 28, 2012 at
www.clinicaltrials.gov as NCT01696084 (
https://clinicaltrials.gov/ct2/show/NCT01696084 ) and is complete. |
Describe the syndrome that is caused by biallelic variants in HPDL | Biallelic HPDL variants cause a syndrome varying from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spastic tetraplegia associated with global developmental delays. | Author information:
(1)Friedrich-Baur-Institute, Department of Neurology, LMU Munich, Munich,
Germany.
(2)Department of Neuromuscular Disorders, Institute of Neurology, University
College London, London, UK.
(3)Department of Biochemistry, National Defense Medical Center, Neihu, Taipei,
Taiwan.
(4)Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
(5)Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
(6)Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
(7)Molecular Medicine Unit, IRCCS Fondazione Stella Maris, Pisa, Italy.
(8)Department of Pediatrics, College of Medicine, Qassim University, Qassim,
Saudi Arabia.
(9)He Key Laboratory of Child Brain Injury, Institute of Neuroscience and
Third Affliated Hospital of Zhengzhou University, Zhengzhou, China.
(10)Center for Brain Repair and Rehabilitation, Institute of Neuroscience and
Physiology, University of Gothenburg, Göteborg, Sweden.
(11)Department of Women's and Children's Health, Karolinska Institutet,
Stockholm, Sweden.
(12)DNA Laboratory, Department of Paediatric Neurology, Second Faculty of
Medicine, Charles University and University Hospital Motol, Prague, Czech
Republic.
(13)Student Research Committee, School of Medicine, Shahid Beheshti University
of Medical Sciences, Tehran, Iran.
(14)Barrow Neurological Institute, Phoenix Children's Hospital and University of
Arizona College of Medicine, Phoenix, USA.
(15)Department of Pediatrics I, Medical University of Innsbruck, Innsbruck,
Austria.
(16)Division of Human Genetics, Medical University of Innsbruck, Innsbruck,
Austria.
(17)Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical
Center, Los Angeles, USA.
(18)Neurology Department, Massachusetts General Hospital, Boston, USA.
(19)Mitochondrial Medicine Frontier Program, Children's Hospital of
Philadelphia, Philadelphia, USA.
(20)Institute of Human Genetics, Technische Universität Mänchen, Munich,
Germany.
(21)Translational Neurosciences, Faculty of Medicine and Health Sciences,
University of Antwerp, Antwerpen, Belgium.
(22)Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of
Antwerp, Antwerpen, Belgium.
(23)Neuromuscular Reference Centre, Department of Neurology, Antwerp University
Hospital, Antwerpen, Belgium.
(24)Center of Medical Genetics, University of Antwerp and Antwerp University
Hospital, Antwerpen, Belgium.
(25)Genetics Division, Department of Pediatrics, King Abdullah International
Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health
Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs
(MNG-HA), Riyadh, Saudi Arabia.
(26)Department of Neurology, Donders Institute for Brain, Cognition and
Behavior, Radboud University Medical Centre, Nijmegen, The Netherlands.
(27)Polikliniek Neurologie Enschede, Medisch Spectrum Twente, Enschede, The
Netherlands.
(28)Medizinische Genetik Mainz, Limbach Genetics, Mainz, Germany.
(29)Department of Medicine, Nephrology, University Hospital Freiburg, Germany.
(30)Genetics Research Center, University of Social Welfare and Rehabilitation
Sciences, Tehran, Iran.
(31)Department of Genetics, Washington University School of Medicine, St. Louis,
USA.
(32)Department of Genetics, Yale University School of Medicine, New Haven, USA.
(33)Yale Center for Genome Analysis, Yale University, New Haven, USA.
(34)Department of Neurology and Psychiatry, Assiut University Hospital, Assiut,
Egypt.
(35)Development and Behavioural Paediatrics Department, Institute of Child
Health and The Children Hospital, Lahore, Pakistan.
(36)Oxford Regional Clinical Genetics Service, Northampton General Hospital,
Northampton, UK.
(37)NIHR Oxford BRC, Wellcome Centre for Human Genetics, University of Oxford,
Oxford, UK.
(38)The National Hospital for Neurology and Neurosurgery, London, UK.
(39)Unité Fonctionnelle 6254 d'Innovation en Diagnostique Génomique des Maladies
Rares, Pôle de Biologie, CHU Dijon Bourgogne, Dijon, France.
(40)Institute of Medical Genetics and Applied Genomics, University of Tübingen,
Tübingen, Germany.
(41)Rare Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
(42)Genetics and Genomics of Rare Diseases Unit, IRCCS Istituto Giannina
Gaslini, Genoa, Italy.
(43)Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
(44)Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics,
Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy.
(45)Pediatric Neurology and Neuromuscular Diseases Unit, IRCCS Istituto Giannina
Gaslini, Genoa, Italy.
(46)Department of Pediatrics, The First Affiliated Hospital of He University
of Chinese Medicine, Zhengzhou, China.
(47)Department of Pediatric Neurology, Osaka Women's and Children's Hospital,
Osaka, Japan.
(48)Department of Neurology, Graduate School of Medical Sciences, University of
Yamanashi, Yamanashi, Japan.
(49)Department of Neurology, Graduate School of Medicine, The University of
Tokyo, Tokyo, Japan.
(50)Institute of Medical Genomics, International University of Health and
Welfare, Chiba, Japan.
(51)Department of Clinical Genetics, CHRU Nancy, UMR_S INSERM N-GERE 1256,
Université de Lorraine - Faculté de Médecine, Nancy, France.
(52)Department of Neuroradiology, CHRU Nancy, Nancy, France.
(53)Department of Medical Genetics, Le Havre Hospital, Le Havre, France.
(54)Department of Pediatric Neurology, University Children's Hospital Tübingen,
Tübingen, Germany.
(55)Roberts Individualized Medical Genetics Center, Division of Human Genetics,
Children's Hospital of Philadelphia, Philadelphia, USA.
(56)Department of Pediatrics, Perelman School of Medicine, University of
Pennsylvania, Philadelphia, USA.
(57)Department of Pediatrics, Naval Medical Center San Diego, San Diego, USA.
(58)Department of Pediatrics, Medical Genetics, Cedars-Sinai Medical Center, Los
Angeles, USA.
(59)Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, USA.
(60)GeneDx, Gaithersburg, USA.
(61)Department of Pediatric Neurology, Akdeniz University Hospital, Antalya,
Turkey.
(62)Department of Pediatric Neurology, Izmir Katip Celebi University, Izmir,
Turkey.
(63)Center for Medical Genetics, Hanusch Hospital, Vienna, Austria.
(64)Medical School, Sigmund Freud Private University, Vienna, Austria.
(65)Hertie Institute for Clinical Brain Research (HIH), Center of Neurology,
University of Tübingen, Tübingen, Germany.
(66)German Center for Neurodegenerative Diseases (DZNE), University of Tübingen,
Tübingen, Germany.
(67)Cologne Center for Genomics, Faculty of Medicine and Cologne University
Hospital, University of Cologne, Cologne, Germany.
(68)Department of Paediatric Neurology, Liberec Hospital, Liberec, Czech
Republic.
(69)Neuroscience Research Center, Faculty of Medicine, Golestan University of
Medical Sciences, Gorgan, Iran.
(70)Dr. John T. Macdonald Foundation Department of Human Genetics, John P.
Hussman Institute for Human Genomics, University of Miami Miller School of
Medicine, Miami, USA.
(71)Department of Clinical Neuroscience, Karolinska Institutet, Stockholm,
Sweden.
(72)Department of Orthopaedics and Traumatology, Medical University of Vienna,
Vienna, Austria.
(73)Department of Translational Genomics, Center for Genomic Medicine, King
Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
(74)Department of Pediatrics, Genetic Unit, Armed Forces Hospital, Khamis
Mushayt, Saudi Arabia.
(75)Hasti Genetic Counseling Center of Welfare Organization of Southern
Khorasan, Birjand, Iran.
(76)Department of Human Genetics, Radboud University Medical Center, Nijmegen,
The Netherlands.
(77)genetikum, Center for Human Genetics, Neu-Ulm, Germany.
(78)Institut für Pharmazeutische Wissenschaften, Albert-Ludwigs-Universität
Freiburg, Freibug, Germany.
(79)Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, USA.
(80)Center for the Undiagnosed Patient, Cedars-Sinai Medical Center, Los
Angeles, USA. |
Which receptor is targeted by Spesolimab? | Spesolimab is a novel anti-interleukin-36 receptor antibody. | The registration of the tumour necrosis factor-α inhibitor adalimumab in 2015
was a major step forward in the treatment of hidradenitis suppurativa/acne
inversa (HS). However, it soon became evident that the effectiveness of
adalimumab in daily practice was highly variable. A significant unmet medical
need of HS patients remained, and the search for novel therapeutic targets was
intensified. During the 10th European Hidradenitis Suppurativa Foundation (EHSF)
e.V. Conference, reknown international HS investigators virtually presented and
discussed the published data on these potential target molecules for future HS
treatment. This article addresses the most promising molecules currently under
investigation from a pathophysiological and clinical point of view. With phase
III trials ongoing, the anti- interleukin (IL)-17 biologics bimekizumab and
secukinumab are in the most advanced stage of clinical development showing
promising results. In addition, targeting IL-1α with bermekimab has shown
encouraging results in two clinical trials. Directing treatment at neutrophil
recruitment and activation by targeting IL-36 with spesolimab fits well in the
pathogenic concept of HS and clinical phase II trial results are pending. In
contrast to in situ evidence, Complement 5a (C5a) and C5a receptor blockade have
only shown greater clinical benefit in patients with severe HS. Inhibition of
Janus kinase (JAK) 1 signalling in HS showed clinical efficacy only in the
highest dosage, highlighting that careful surveillance of the balance between
safety and efficacy of JAK inhibition is warranted. Overall, clinical efficacies
of all novel treatments reported so far are modest. To guide drug development,
more and better-defined translational data on the pathogenesis of this severe
and enigmatic inflammatory skin disease are required. Pustular psoriasis is an unusual form of psoriasis that frequently presents
clinical challenges for dermatologists. The condition presents with pustules on
an erythematous background and has two distinct subtypes: localized disease on
the palms and soles, called palmoplantar pustulosis (PPP), and generalized
pustular psoriasis (GPP). The involvement of the fingers, toes, and nails is
defined as a separate localized variant, acrodermatitis continua of Hallopeau,
and is now thought to be a subset of PPP. The rarity of pustular psoriasis
frequently makes the correct diagnosis problematic. In addition, treatment is
limited by a relative lack of evidence-based therapeutic options. Current
management is often based on existing therapies for standard plaque psoriasis.
However, there remains a need for treatments with high, sustained efficacy and a
rapid onset of action in pustular psoriasis. Recent advances in understanding of
the pathogenesis of pustular psoriasis have provided insights into potential
therapies. Treatment of pustular psoriasis is generally determined by the extent
and severity of disease, and recent years have seen an increasing use of newer
agents, including biologic therapies. Current classes of biologic therapies with
US Food and Drug Administration and European Medicines Agency approval for
treatment of moderate-to-severe plaque psoriasis in the USA (and elsewhere)
include tumor necrosis factor alpha inhibitors (adalimumab, certolizumab pegol,
etanercept, infliximab), interleukin (IL)-17 inhibitors (brodalumab, ixekizumab,
secukinumab), an IL-12/23 inhibitor (ustekinumab), and IL-23 inhibitors
(guselkumab, risankizumab, tildrakizumab). Recently, specific inhibitors of the
IL-36 pathway have been evaluated in GPP and PPP, including spesolimab, an IL-36
receptor inhibitor which has shown promising results in GPP. The emerging drugs
for pustular psoriasis offer the possibility of rapid and effective treatment
with lower toxicities than existing therapies. Further research into agents
acting on the IL-36 pathway and other targeted therapies has the potential to
transform the future treatment of patients with pustular psoriasis. This article
reviews the clinical features of PPP and GPP, and current understanding of the
genetics and immunopathology of these conditions; it also provides an update on
emerging treatments. BACKGROUND: The IL-36 pathway plays a key role in the pathogenesis of
generalized pustular psoriasis (GPP). In a proof-of-concept clinical trial,
treatment with spesolimab, an anti-IL-36 receptor antibody, resulted in rapid
skin and pustular clearance in patients presenting with GPP flares.
OBJECTIVE: We sought to compare the molecular profiles of lesional and
nonlesional skin from patients with GPP or palmoplantar pustulosis (PPP) with
skin from healthy volunteers, and to investigate the molecular changes after
spesolimab treatment in the skin and blood of patients with GPP flares.
METHODS: Pre- and post-treatment skin and blood samples were collected from
patients with GPP who participated in a single-arm, phase I study (n = 7). Skin
biopsies from patients with PPP (n = 8) and healthy volunteers (n = 16) were
obtained for comparison at baseline. Biomarkers were assessed by RNA-sequencing,
histopathology, and immunohistochemistry.
RESULTS: In GPP and PPP lesions, 1287 transcripts were commonly upregulated or
downregulated. Selected transcripts from the IL-36 signaling pathway were
upregulated in untreated GPP and PPP lesions. In patients with GPP, IL-36
pathway-related signatures, TH1/TH17 and innate inflammation signaling,
neutrophilic mediators, and keratinocyte-driven inflammation pathways were
downregulated by spesolimab as early as week 1. Spesolimab also decreased
related serum biomarkers and cell populations in the skin lesions from patients
with GPP, including CD3+ T, CD11c+, and IL-36γ+ cells and lipocalin-2-expressing
cells.
CONCLUSIONS: In patients with GPP, spesolimab showed rapid modulation of
commonly dysregulated molecular pathways in GPP and PPP, which may be associated
with improved clinical outcomes. |