Kinetic networks identify TWIST2 as a key regulatory node in adipogenesis.

Adipocytes contribute to metabolic disorders such as obesity, diabetes, and atherosclerosis. Prior characterizations of the transcriptional network driving adipogenesis have overlooked transiently acting transcription factors (TFs), genes, and regulatory elements that are essential for proper differentiation. Moreover, traditional gene regulatory networks provide neither mechanistic details about individual regulatory element-gene relationships nor temporal information needed to define a regulatory hierarchy that prioritizes key regulatory factors. To address these shortcomings, we integrate kinetic chromatin accessibility (ATAC-seq) and nascent transcription (PRO-seq) data to generate temporally resolved networks that describe TF binding events and resultant effects on target gene expression. Our data indicate which TF families cooperate with and antagonize each other to regulate adipogenesis. Compartment modeling of RNA polymerase density quantifies how individual TFs mechanistically contribute to distinct steps in transcription. The glucocorticoid receptor activates transcription by inducing RNA polymerase pause release, whereas SP and AP-1 factors affect RNA polymerase initiation. We identify Twist2 as a previously unappreciated effector of adipocyte differentiation. We find that TWIST2 acts as a negative regulator of 3T3-L1 and primary preadipocyte differentiation. We confirm that Twist2 knockout mice have compromised lipid storage within subcutaneous and brown adipose tissue. Previous phenotyping of Twist2 knockout mice and Setleis syndrome Twist2 -/- patients noted deficiencies in subcutaneous adipose tissue. This network inference framework is a powerful and general approach for interpreting complex biological phenomena and can be applied to a wide range of cellular processes.

Exploring the evidence for mitochondrial dysfunction and genetic abnormalities in the etiopathogenesis of tropical ataxic neuropathy.

Tropical ataxic neuropathy (TAN) is characterised by ataxic polyneuropathy, degeneration of the posterior columns and pyramidal tracts, optic atrophy, and sensorineural hearing loss. It has been attributed to nutritional/toxic etiologies, but evidence for the same has been equivocal. TAN shares common clinical features with inherited neuropathies and mitochondrial disorders, it may be hypothesised that genetic abnormalities may underlie the pathophysiology of TAN. This study aimed to establish evidence for mitochondrial dysfunction by adopting an integrated biochemical and multipronged genetic analysis. Patients (n = 65) with chronic progressive ataxic neuropathy with involvement of visual and/or auditory pathways underwent deep phenotyping, genetic studies including mitochondrial DNA (mtDNA) deletion analysis, mtDNA and clinical exome sequencing (CES), and respiratory chain complex (RCC) assay. The phenotypic characteristics included dysfunction of visual (n = 14), auditory (n = 12) and visual + auditory pathways (n = 29). Reduced RCC activity was present in 13 patients. Mitochondrial DNA deletions were noted in five patients. Sequencing of mtDNA (n = 45) identified a homoplasmic variant (MT-ND6) and a heteroplasmic variant (MT-COI) in one patient each. CES (n = 45) revealed 55 variants in nuclear genes that are associated with neuropathy (n = 27), deafness (n = 7), ataxia (n = 4), and mitochondrial phenotypes (n = 5) in 36 patients. This study provides preliminary evidence that TAN is associated with a spectrum of genetic abnormalities, including those associated with mitochondrial dysfunction, which is in contradistinction from the prevailing hypothesis that TAN is related to dietary toxins. Analysing the functional relevance of these genetic variants may improve the understanding of the pathogenesis of TAN.

Non-invasive markers of inflammation in alcohol-associated liver disease: A scoping review.

Clinical manifestations of liver inflammation in alcohol-associated liver disease (ALD) can range from asymptomatic to severe alcoholic hepatitis. While biopsy is the gold standard for identifying liver inflammation, it is an invasive procedure with risks of bleeding, visceral damage, and infection. We aim to establish the state of the current literature on non-invasive markers of inflammation in ALD. We searched Ovid MEDLINE, Embase, and the Cochrane Library for original studies on the association between one or more non-invasive biomarker(s) and histological inflammation or hepatitis in ALD patients. Exclusion criteria were lack of histological data, abstract only, non-English-language articles, and animal studies. Two independent reviewers screened abstracts, reviewed full texts, and extracted data from included papers. Our search identified 8051 unique studies. Title and abstract screening resulted in 563 studies, and full-text screening resulted in 31 studies for final inclusion. The majority were single-center observational cohorts with an average sample size of 124. Review of these studies identified 44 unique biomarkers and 8 calculated scores associated with histological inflammation and/or hepatitis, in addition to a metabolomic panel of 468 metabolites. Six studies examined diagnostic accuracy for histological inflammation and/or hepatitis. The highest area under the receiver operating characteristic curve was 0.932 using a model based on four metabolites. This review highlights the available literature on non-invasive markers of inflammation in ALD. There is a dearth of studies that evaluate the diagnostic accuracy of these biomarkers, and larger studies are needed to confirm findings identified in small cohorts.

Hyponatremia in Guillain-Barre Syndrome: A Review of Its Pathophysiology and Management.

Guillain-Barre syndrome (GBS) is the commonest cause of acute polyradiculoneuropathy that requires hospitalization. Many of these patients experience systemic and disease-related complications during its course. Notable among them is hyponatremia. Though recognized for decades, the precise incidence, prevalence, and mechanism of hyponatremia in GBS are not well known. Hyponatremia in GBS patients is associated with more severe in-hospital disease course, prolonged hospitalization, higher mortality, increased costs, and a greater number of other complications in the hospital and worse functional status at 6 months and at 1 year. Though there are several reports of low sodium associated with GBS, many have not included the exact temporal relationship of sodium or its serial values during GBS thereby underestimating the exact incidence, prevalence, and magnitude of the problem. Early detection, close monitoring, and better understanding of the pathophysiology of hyponatremia have therapeutic implications. We review the complexities of the relationship between hyponatremia and GBS with regard to its pathophysiology and treatment.

High-flow Tracheal Oxygenation with Airway Exchange Catheter: A Novel Approach.

How to cite this article: Vaithialingam B, Arun BG. High-flow Tracheal Oxygenation with Airway Exchange Catheter: A Novel Approach. Indian J Crit Care Med 2023;27(6):456.

Veliparib monotherapy following carboplatin/paclitaxel plus veliparib combination therapy in patients with germline BRCA-associated advanced breast cancer: results of exploratory analyses from the phase III BROCADE3 trial.

BACKGROUND: In the BROCADE3 trial, addition of the poly(ADP-ribose) polymerase inhibitor, veliparib, to carboplatin/paclitaxel improved progression-free survival (PFS) (hazard ratio 0.71, 95% confidence interval 0.57-0.88; P = 0.002) in patients with advanced human epidermal growth factor receptor 2-negative, germline BRCA1/2-mutated breast cancer. A subset of patients discontinued both carboplatin and paclitaxel before progression and continued on veliparib/placebo maintenance monotherapy until progression. Analyses in this patient subgroup are reported. PATIENTS AND METHODS: Patients were randomized 2 : 1 to veliparib plus carboplatin/paclitaxel or placebo plus carboplatin/paclitaxel. Veliparib (120 mg twice daily) or placebo was given on days -2 to 5, carboplatin (area under the curve 6 mg/ml) on day 1, and paclitaxel (80 mg/m2) on days 1, 8, and 15 of 21-day cycles. Patients who discontinued both carboplatin and paclitaxel before progression received blinded study drug monotherapy at an increased dose of 300-400 mg twice daily continuously. PFS was the primary endpoint. Exploratory analyses were carried out in the subgroup of patients who received blinded study drug as monotherapy. A time-varying Cox model including data from all patients was also used to evaluate treatment effect in the combination and monotherapy phases. RESULTS: A total of 136 of 337 patients randomized to veliparib plus carboplatin/paclitaxel and 58/172 patients randomized to placebo plus carboplatin/paclitaxel discontinued both carboplatin and paclitaxel before progression and continued on blinded veliparib or placebo monotherapy. In this blinded monotherapy subgroup, investigator-assessed median PFS from randomization was 25.7 months with veliparib versus 14.6 months with placebo. Hazard ratios from a time-varying Cox model favored veliparib during both combination therapy and monotherapy. Any-grade adverse events occurring in the monotherapy phase were primarily gastrointestinal. The most common grade ≥3 adverse events were neutropenia and anemia (4% each with veliparib; 5% and 2%, respectively, with placebo). CONCLUSIONS: Veliparib maintenance monotherapy had a tolerable safety profile and may extend PFS following combination chemotherapy.

Novel insights into the genetic profile of hereditary spastic paraplegia in India.

The Hereditary Spastic Paraplegias (HSPs) are a group of clinically and genetically heterogeneous disorders characterized by length dependent degeneration of the corticospinal tracts. Genetic data related to HSPs are limited from India. We aimed to comprehensively analyse the phenotypic characteristics and genetic basis of a large cohort of HSP from India. Patients with HSP phenotype were evaluated for their clinical features, electrophysiological and radiological abnormalities. Genetic analyses were carried out by clinical exome sequencing (n = 52) and targeted sequencing (n = 5). The cohort comprised of 57 probands (M:F 40:17, age: 3.5-49 years). Based on the phenotype, the cohort could be categorized as 'pure' (n = 15, 26.3%) and 'complicated' (n = 42, 73.7%) HSP. Brain MRI showed thin corpus callosum (n = 10), periventricular hyperintensities (n = 20), cerebral atrophy (n = 3), cerebellar atrophy (n = 3) and diffuse atrophy (n = 4). Sixty-seven variants representing 40 genes were identified including 47 novel variants. Forty-eight patients (84.2%) had variants in genes previously implicated in HSP and other spastic paraplegia syndromes (SPG genes = 24, non-SPG genes = 24); among these 13 had variations in more than one gene and 12 patients (21.0%) had variations in genes implicated in potentially treatable/modifiable metabolic disorders (MTHFR = 8, MTRR = 1, ARG1 = 2 and ABCD1 = 1). In nine patients, no genetic variants implicated in spastic paraplegia phenotype were identified. Thus, the present study from India highlights the phenotypic complexities and spectrum of genetic variations in patients with HSP including those implicated in metabolically modifiable disorders. It sets a platform for carrying out functional studies to validate the causal role of the novel variants and variants of uncertain significance.

Preclinical development of the quadrivalent meningococcal (ACYW) tetanus toxoid conjugate vaccine, MenQuadfi®.

Bacterial capsular polysaccharide vaccines are generally poorly immunogenic in infants and older adults. The immunogenicity of capsular polysaccharide vaccines can be improved by conjugating them to immunogenic carrier proteins. One of the most recently licensed conjugate vaccines is the quadrivalent meningococcal vaccine with serogroups A, C, Y, and W conjugated to a tetanus toxoid protein carrier (MenACYW-TT; MenQuadfi, Sanofi Pasteur, Swiftwater, PA, USA). MenACYW-TT was developed to induce optimal immune responses against each of the meningococcal serogroups A, C, W, and Y, and across all age groups, especially infants and older adults (those aged ≥ 50 years). Here, we detail the early iterative vaccine development approach taken, whereby many different 'small-scale' conjugate vaccine candidates were prepared and examined for immunogenicity in a mouse model to identify the most immunogenic vaccine. Additional insights from phase I clinical studies informed further optimization of the vaccine candidates by tailoring their conjugation parameter attributes for the optimal immune response in humans. The parameters studied included: different carrier proteins [PR]; polysaccharide [PS] sizes; conjugation chemistries [linker vs. no-linker; lattice vs. neoglycoprotein; activation/derivatization levels]; conjugate size; PS:PR loading ratio; percent free PS; percent free PR; and O-acetylation content. The lead quadrivalent conjugate vaccine (polysaccharides of > 50 kDa size conjugated to TT at a high PS:PR ratio via reductive amination for serogroups C, W and Y, and carbonyldiimidazole/adipic acid dihydrazide linker chemistry for serogroup A) empirically identified from the extensive preclinical studies, was ultimately confirmed by the robust antibody responses observed in all age groups in the various clinical studies, including in the most challenging infant and older adult age groups, and subsequently led to the licensed formulation.

Role of altered IL-33/ST2 immune axis in the immunobiology of Guillain-Barré syndrome.

BACKGROUND: The IL-33/ST2 immune axis plays crucial roles in infection and immunity. A dysregulated IL-33/ST2 axis can induce autoimmune reaction and inflammatory responses. Guillain-Barré syndrome (GBS) is an acute peripheral neuropathy, mostly caused by post-infection autoimmunity. The role of IL-33/ST2 axis is not known in GBS. This study aimed to explore the role of IL-33/ST2 axis in GBS. METHODS: Three single nucleotide polymorphisms (SNPs) of Il33 gene (rs16924159, rs7044343, rs1342336) and three SNPs of Il1rl1 gene (rs10192157, rs1041973, rs10206753) coding for suppressor of tumorigenicity 2 (ST2) were genotyped in 179 GBS patients and 186 healthy controls by TaqMan Allelic Discrimination Assay. Plasma levels of IL-33 and sST2 were measured in a subset of GBS patients (n = 80) and healthy controls (n = 80) by ELISA. RESULTS: The frequencies of CC genotype of rs10192157 (p = 0.043) and TT genotype of rs10206753 (p = 0.036) SNPs of Il1rl1 gene differed significantly between GBS patients and healthy controls. Gene-gene interaction between Il33 and Il1rl1 genes also conferred significant risk for GBS. In addition, the plasma sST2 levels were significantly elevated in GBS patients compared to healthy subjects (24,934.31 ± 1.81 pg/ml vs. 12,518.97 ± 1.51 pg/ml, p < 0.001). Plasma sST2 levels showed a significant correlation with the disability scores at the peak of neurological deficit in GBS patients. CONCLUSIONS: The IL-33/ST2 axis is suggested to influence the immunopathogenesis of GBS. Genetic variants of Il1rl1 gene might serve as a risk determinant of GBS and plasma sST2 levels might emerge as a biomarker of severity of GBS, if replicated further by other studies.

Variations within Toll-like receptor (TLR) and TLR signaling pathway-related genes and their synergistic effects on the risk of Guillain-Barré syndrome.

Guillain-Barré syndrome (GBS) is the commonest post-infectious polyradiculopathy. Although genetic background of the host seems to play an important role in the susceptibility to GBS, genes conferring major risk are not yet known. Dysregulation of Toll-like receptor (TLR) molecules exacerbates immune-inflammatory responses and the genetic variations within TLR pathway-related genes contribute to differential risk to infection. The aim of this study was to delineate the impact of genetic variations within TLR2, TLR3, and TLR4 genes as well as TLR signaling pathway-related genes such as MyD88, TRIF, TRAF3, TRAF6, IRF3, NFκß1, and IκBα on risk of developing GBS. Fourteen polymorphisms located within TLR2 (rs3804099, rs111200466), TLR3 (rs3775290, rs3775291), TLR4 (rs1927911, rs11536891), MyD88 (rs7744, rs4988453), TRIF (rs8120), TRAF3 (rs12147254), TRAF6 (rs4755453), IRF3 (rs2304204), NFκß1 (rs28362491), and IκBα (rs696) genes were genotyped in 150 GBS patients and 150 healthy subjects either by PCR-RFLP or TaqMan Allelic Discrimination Assay. Genotypes of two polymorphic variants, Del/Del of rs111200466 insertion and deletion (INDEL) polymorphism of TLR2 gene and TT of rs3775290 single nucleotide polymorphism (SNP) of TLR3 gene had significantly higher frequencies among GBS patients, while the frequencies of TT genotype of rs3804099 SNP of TLR2 gene and TT genotype of rs11536891 SNP of TLR4 gene were significantly higher in controls. Gene-gene interaction study by Multifactor Dimensionality Reduction analysis also suggested a significant combined effect of TLR2, and NFκß1 genes on the risk of GBS. The SNPs in the IκBα and IRF3 genes correlated with severity of GBS. The genes encoding TLRs and TLR signaling pathway-related molecules could serve as crucial genetic markers of susceptibility and severity of GBS.

Leukodystrophy Due to eIF2B Mutations in Adults.

Vanishing white matter disease (VWMD) due to eIF2B mutations is a common leukodystrophy characterised by childhood onset, autosomal recessive inheritance, and progressive clinical course with episodic worsening. There are no reports of genetically confirmed adult patients from India. We describe the phenotype of two adults with genetically confirmed VWMD and typical radiological findings. Both had spastic ataxia and cognitive and behavioural disturbances. Other neurological features included myoclonic jerks and parkinsonism. At the last follow-up (duration: 2-9 years), one patient was wheelchair-bound. VWMD is rare in adults but should be suspected based on radiological findings and confirmed by eIF2B mutation.

Intersecting sex-related inequalities in self-reported testing for and prevalence of Non-Communicable Disease (NCD) risk factors in Kerala.

BACKGROUND: Non-Communicable Diseases (NCDs) are among India's top burdens, particularly in states like Kerala, which is at an advanced stage of the epidemiological transition. Evidence in India points towards intersectional inequalities in risk factors of NCDs and testing, both of which are understudied in Kerala. We estimated the self-reported testing and prevalence of key NCD risk factors-blood pressure (BP) and blood glucose (BG) comparing Kerala men and women across educational, wealth, religion, as well as caste and tribal status subgroups. METHOD: A multistage random sample survey of 3398 women and 2982 men aged 30 years and over was administered in 4 districts of Kerala from July to October 2019. Descriptive analysis for men and women was undertaken using survey weights. Slope index of Inequality and Relative Concentration Index for wealth and education related inequalities, and, Weighted Mean Difference from Mean and Index of Disparity for caste and tribal status, as well as religion related inequalities were calculated using World Health Organisation's Health Equity Assessment Toolkit Plus and Stata 12. RESULTS: A significantly higher proportion of women reported BP and BG testing by medical personnel in the previous year than men (BP Testing among Women (BPTw): 90.3% vs BP Testing among Men (BPTM):80.8%, BG Testing among Women (BGTw): 86.2% vs BG Testing among Women (BGTM):78.3%). Among those tested, more women (11.2%) than men (7.9%) reported High Blood Pressure (HBP) but not High Blood Glucose (HBG). Testing for BP was concentrated among less-educated women while BG testing was concentrated among both less educated women and men. HBP and HBG were concentrated among less educated and wealthier groups. Although sex differences were insignificant across caste and tribal status and religion subgroups, magnitude of inequalities was high for HBP and HBG. CONCLUSION: Distinct patterns of sex inequalities were present in self-reported testing and prevalence of NCD risk factors in Kerala. Education and wealth seem to be associated with testing while prevalence appeared to vary by religious groups. Given the low rates of illiteracy, it is encouraging but maybe a data artefact that a small population of less-educated persons was getting tested; however, exclusion of poor groups and inequalities by other dimensions raise concerns. Further exploration is needed to understand underlying mechanisms of these inequalities to ensure we leave no one behind.

Antecedent infections in Guillain-Barré syndrome patients from south India.

Guillain-Barré syndrome (GBS) is the commonest post-infectious inflammatory peripheral neuropathy with undiscerned aetiology. The commonly reported antecedent infections implicated in India include Campylobacter jejuni, chikungunya, dengue, and Japanese encephalitis (JE). In this study from south India, we investigated the role of these four agents in triggering GBS. This case-control study was performed on 150 treatment-naive patients with GBS and 150 age and sex-matched controls from the same community. IgM immunoreactivity for C. jejuni, chikungunya, and dengue was detected by enzyme-linked immunosorbent assay (ELISA) in serum of patients with GBS and control subjects. Immunoreactivity against JE was detected in serum as well as cerebrospinal fluid (CSF) from patients (n = 150) and orthopaedic control (n = 45) subjects. The immunoreactivity against infections was compared between demyelinating and axonal subtypes of GBS. Overall, 119/150 patients with GBS had serological evidence of antecedent infection. Amongst those with evidence of antecedent infection, 24 (16%), 8 (5%), and 9 (6%) patients were exclusively immunoreactive to chikungunya, JE, and C. jejuni, respectively. In the remaining patients (78/119), immunoreactivity to multiple pathogens was noted. Immunoreactivity to C. jejuni infection was found in 32% of GBS patients compared to 2.7% controls (P < .001), whereas to chikungunya virus was reported in 66.7% of patients with GBS compared to 44.7% controls (P = .006). Anti-dengue immunoreactivity was significantly associated with the demyelinating subtype of GBS. Patients positive for JE IgM (CSF) manifested demyelinating electrophysiology. In this large case-control study, immunoreactivity against multiple infectious agents was observed in a subset of patients. Chikungunya was the commonest antecedent infection, followed by C. jejuni.

Prediction of leg length change (LLC) after correcting varus and flexion deformity in patients undergoing TKA.

PURPOSE: Patients with varus and fixed flexion deformity (FFD) undergoing TKA may have a significant leg length change (LLC) after surgery. We aimed to determine the correlation between changes in HKA or FFD and leg length in patients undergoing TKA, the combined effect of coronal and sagittal plane deformity correction on LLC, and the possibility of estimating LLC mathematically. MATERIALS AND METHODS: This was a prospective radiographic evaluation of 242 knees, which had undergone primary unilateral TKA for advanced OA with varus and FFD. Full-length standing calibrated anteroposterior radiographs were used to measure the hip-knee-ankle axis (HKA) and functional leg length after adjusting for magnification. Clinical evaluation of FFD was done using a handheld goniometer. RESULTS: 224 knees (92.6%) showed increased limb length after TKA averaging 10.7 mm (SD 9.5 mm, P = .000). There was a significant correlation between the change in HKA and FFD from preoperatively to postoperatively with the amount of LLC (ρ 0.326 and 0.346, respectively, P = .000). FFD improvement from preoperatively to postoperatively was 8.1° to 1° (P = .000), respectively. A linear relationship was established between LLC and changes in HKA and FFD, where 10° improvement in HKA would result in an LLC of nearly 4 mm, and 10° improvement in FFD would result in a LLC of nearly 8 mm. CONCLUSION: LLC may be substantial after correcting varus and FFD with unilateral TKA, it correlates with the change in HKA and FFD and can be mathematically estimated. CLINICAL TRIALS . GOV IDENTIFIER: NCT03502382.

Ganglioside complex antibodies in an Indian cohort of Guillain-Barré syndrome.

BACKGROUND: Antibodies against ganglioside complexes (GSCs) are associated with various clinical features and subtypes of Guillain-Barré syndrome (GBS). METHODS: One-hundred patients were evaluated for antibodies to GSCs formed by combination of GM1, GM2, GD1a, GD1b, GT1b, and GQ1b using manual enzyme linked immuno-sorbent assay (ELISA). RESULTS: Twenty-six patients were GSC antibody-positive, most frequent being against GM1-containing GSC (76.9%). Gender distribution, mean age, symptom-duration, antecedent events, electrophysiological subtypes, requirement for mechanical ventilation, and median duration of hospital stay were comparable between the GSC antibody-positive and negative groups. There was no association between specific GSC antibody and electrophysiological subtypes or clinical variants. After controlling for false discovery rate (FDR) using the Benjamini-Hochberg method, the number of subjects who improved in overall disability sum score, modified Erasmus GBS outcome score, and neuropathy symptom score at discharge was significantly higher in the GSC antibody-positive group. Improvements in Medical Research Council sum scores and Hughes Disability Scale during the hospital stay between the GSC antibody-positive and negative groups were not significantly different after controlling for FDR. CONCLUSIONS: The GSC antibody-positive group had better outcome at hospital discharge in some of the disability scores. Pathophysiological pathways among patients without GSC antibodies may be different and this requires further evaluation.