Iti Garg

DNA methylation being one of the chief controllers of gene expression has not only been the reason behind the initiation of a plethora of diseases like Cancer, Alzheimer’s disease, Parkinson’s disease, etc. Still, it is an active contributor to the pathophysiology of several cardiovascular diseases like coronary artery disease (CAD), Atherosclerosis, Stroke, Cardiomyopathy, etc. The role of nuclear DNA methylation in VTE has been studied earlier, but the comparison of methylation in both nuclear genes and mitochondrial genes in high altitude VTE (HA-VTE) and sea level VTE (SL-VTE) patients has not been studied in depth. Through this present study, DNA methylation patterns of mitochondrial encoded as well as nuclear-encoded mitochondrial genes of five high-altitude VTE patients and five sea-level VTE patients have been obtained. On comparing HA-VTE vs. SL-VTE methylation, one hundred and twenty hypermethylated genes and one hundred and thirty-eight hypomethylated genes were observed. Post gene enrichment and ontology study, the TCA cycle and NADH dehydrogenase were found to be the highly enriched pathways in both the study groups. Protein-protein interaction network using STRING pointed out the enriched pathway of L-2-hydroxyglutaric acid when both the gene sets were enriched. These results show the crucial role of mitochondrial DNA methylation in the pathophysiology of thrombosis and show great potential to study the role of mitochondria in thrombosis.

Cardiovascular diseases (CVD) are a cluster of diseases that hamper cardiovascular system and may lead to death. Several injuries and risk factors like obesity correspond to the malfunctioning of heart and blood vessels that lead to the condition of stroke, myocardial infarction, deep vein thrombosis (DVT), etc. Only a few studies have depicted the role of mitochondrial genes and their epigenetic regulation in DVT. The association of certain mitochondrial genes of electron transport chain and oxidative phosphorylation has been reported in CVD. Expression of these genes is regulated by DNA methylation. Obesity not only influences the CVD but also has been found responsible for alteration in mtDNA methylation. In present study, of the 5182 research articles, only 13 and 4 papers were found dealing with the qualitative and quantitative analysis, respectively. MT-CO1, MT-CO2, MT-CO3, MT-TL1 and PPARGC1 genes were noted to be involved in disease condition. The mitochondrial DNA methylation has profound impact on mitochondrial gene expression which may lead to the development of dysfunctional mitochondria and cause the development of various cardiovascular diseases. In present paper, a systemic analysis was done with the hypothesis that mitochondrial DNA methylation has an intriguing role in the occurrence of several CVDs in relation to obesity.

Introduction: Coronavirus disease 2019 (COVID-19) is a novel viral disease that spread as a global pandemic in 2020 by infecting millions of people across the world. Its clinical prognosis is dependent on various coagulatory parameters since thrombotic events are frequently associated with infection severity. Methods: A total of 383 COVID-19 patients enrolled in Rajiv Gandhi Super Specialty Hospital, Delhi, India, were included in the present retrospective study. Patients were divided into three categories, severe (n = 141), moderate (n = 138), and mild (n = 104) based on infection severity. Various thrombotic parameters and anticoagulant levels were measured in 70 patients and further analyzed. Results: Coagulopathy is seen in COVID-19 patients (n = 70) with a significant increase in fibrinogen, D-dimer levels, and prothrombin time in patients with severe and moderate disease compared to patients with a mild infection. Approximately, 70% of patients with severe and moderate disease demonstrated fibrinogen levels higher than the standard reference range. 60.41% of patients with severe disease showed significantly higher D-dimer levels. Thrombotic parameters were notably elevated in the nonsurvivors group compared to COVID-19 survivors. Nearly, 91% of patients with severe infection had anticoagulant protein S levels below the reference range. Conclusion: COVID-19 infection severely impacts the blood coagulation cascade, which might lead to the manifestation of severe symptoms and increased mortality in patients.

Abnormal blood coagulation may lead to venous thromboembolism (VTE), a complex multifactorial disease. Hypoxia (oxygen deprivation) is a major factor disturbing the blood hemostasis and predisposing the body towards coagulation and VTE. Pathophysiology of VTE can be attributed to post-transcriptional gene regulation by microRNAs (miRNAs). The present study identified regulatory miRNAs involved in causing blood coagulation under normoxic and hypoxic conditions. Meta-analysis was performed, following PRISMA guidelines, for identifying miRNAs involved in blood coagulation pathway. Studies evaluating miRNAs from circulating blood as potential biomarkers of VTE were selected. A total of 16 studies met selection criteria and 8 having complete statistical information were selected for analysis. Study of blood coagulation mechanism under hypoxic conditions involved in-silico search within highly cited databases to identify miRNAs commonly regulating genes of hypoxia-inducible factor (HIF) family and coagulation pathway. Further bio-informatics approaches were employed to identify potential biomarker candidates. Meta-analysis revealed a panel of 12 miRNAs; two members of miR-27 family, hsa-miR-27a and hsa-miR-27b; two members of miR-320 family, hsa-miR-320a and hsa-miR-320b, hsa-miR-1233, hsa-miR-134, hsa-miR-424-5p, hsa-miR-221, hsa-miR-28-3p, hsa-miR-136-5p, hsa-miR-374-5p and hsa-miR-338-5p involved in blood coagulation under normoxic conditions. Besides these, present in-silico analysis identified a set of 5 miRNAs including hsa-miR-4667-5p, hsa-miR-6815-3, hsa-miR-4433a-3p, hsa-miR-6735-5p and hsa-miR-6777-3p which predominantly regulate genes that facilitate both coagulation and response to hypoxic stress. The present study generated a panel of regulatory miRNAs potentially involved in the process of blood coagulation under both normoxic and hypoxic conditions, which may serve as putative epigenetic biomarkers for coagulation.

Outbreak of COVID-19 pandemic in December 2019 affected millions of people globally. After substantial research, there is no specific and reliable biomarker available till date. Present study was designed to identify specific biomarkers to predict COVID-19 severity and tool for formulating treatment. A small cohort of subjects (n=43) were enrolled and categorized in four study groups; Dead (n=16), Severe (n=10) and Moderate (n=7) patients and healthy controls (n=10). Small RNA sequencing was done on Illumina platform after isolation of microRNA from peripheral blood. Differential expression (DE) of miRNA (patients groups compared to control) revealed 118 down-regulated and 103 up-regulated known miRNAs with fold change (FC) expression ≥2 folds and p≤0.05. DE miRNAs were then subjected to functional enrichment and network analysis. Bioinformatic analysis resulted in 31 miRNAs (24 Down-regulated; 7 up-regulated) significantly associated with COVID-19 having AUC>0.8 obtained from ROC curve. Seventeen out of 31 DE miRNAs have been linked to COVID-19 in previous studies. Three miRNAs, hsa-miR-147b-5p and hsa-miR-107 (down-regulated) and hsa-miR-1299 (up-regulated) showed significant unique DE in Dead patients. Another set of 4 miRNAs, hsa-miR-224-5p (down-regulated) and hsa-miR-4659b-3p, hsa-miR-495-3p and hsa-miR-335-3p were differentially up-regulated uniquely in Severe patients. Members of three miRNA families, hsa-miR-20, hsa-miR-32 and hsa-miR-548 were significantly down-regulated in all patients group in comparison to healthy controls. Thus a distinct miRNA expression profile was observed in Dead, Severe and Moderate COVID-19 patients. Present study suggests a panel of miRNAs which identified in COVID-19 patients and could be utilized as potential diagnostic biomarkers for predicting COVID-19 severity.

Novel coronavirus disease by SARS-CoV-2 virus (also known as COVID-19) has emerged as major health concern worldwide. While, there is no specific drugs for treating this infection till date, SARS-CoV-2 had spread to most countries around the globe. Nitric oxide (NO) gas serves as an important signaling molecule having vasodilatory effects as well as anti-microbial properties. Previous studies from the 2004 SARS-CoV infection demonstrated that NO may also help to reduce respiratory tract infection by inactivating viruses and inhibiting their replication cycle and is an effective supportive measure for treating infection in patients with pulmonary complications. NO gas inhalation is being suggested as potential therapy for managing severe acute respiratory distress syndrome in COVID-19 patients. In view of COVID-19 pandemic, several clinical trials are underway to examine the effects of NO inhalation on infected patients. Previously published reports on beneficial effects of endogenous NO and NO inhalation therapy were thoroughly searched to assess the potential of NO therapy for treating COVID-19 patients. Present report summarized the therapeutic importance of NO to reverse pulmonary hypertension, restore normal endothelial activity and produce anti-thrombotic effects. In addition to this, NO also reduces viral infection by inhibiting its replication and entry into the host cell. In absence of vaccine and effective treatment strategies, we suggest that NO inhalation therapy and NO releasing foods/compounds could be considered as an alternative measure to combat COVID-19 infection.