Browsing by Author "Sharma, N"

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Anti-cancer drug doxorubicin induced cardiotoxicity: Understanding the mechanisms involved in ros generation resulting in mitochondrial dysfunction
(Rasayan Journal of Chemistry, c/o Dr. Pratima Sharma, 2020) Upadhayay, S; Sharma, N; Mantha, A.K; Dhiman, M.
Doxorubicin (DOX), despite being an effective anti-cancer drug has offsite targets that affect the vital organs such as heart, brain and kidney. DOX-induced cardiotoxicity is reported as a multi-factorial process that interferes with mitochondrial bioenergetics. These responses increase the threshold of oxidant-mediated injury and redox-mediated apoptosis in the cardiomyocytes. Oxidative stress particularly mitochondrial dysfunction in cardiomyocytes associated with cardiovascular diseases. In the present study we examined the effect of DOX on H9c2 cardiomyocyte where cells were treated with 5 μM DOX. To rule out the source of reactive oxygen species (ROS) during DOX-induced toxicity, the DOX-treated cardiomyocytes were incubated with 100 ?M diphenyleneiodonium (DPI), 50 μM salicyl hydroxamic acid (SHX), 20 μM Carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (FCCP), which are specific inhibitors of NADPH oxidase (NOX), Myeloperoxidase (MPO), and mitochondrial oxidative phosphorylation respectively and 10 μM N-acetyl cysteine (NAC, free radical scavenger) was also used to perceive the role of ROS. H2O2 (100 ?M) treated H9c2 cardiomyocytes were used as positive controls. The cell viability, reactive oxygen species (ROS) level and oxidative stress were determined using MTT assay, NBT assay/Flow-cytometry and Western blotting based assays. The effect of DOX on mitochondria was evaluated using Amplex Red assay; fluorescent probes such as MitoSOX and MitoTracker were used to examine the DOX-induced ROS production from the mitochondrial matrix. The mitochondrial membrane potential was evaluated using JC-1 dye. Western blotting was performed for cytochrome c release and apoptosis was examined with Annexin V-FITC assay. DOX was found to reduce cell viability, increase ROS level followed by enhanced oxidative stress in the form of protein carbonyls. DOX also showed a reduction in the mitochondrial membrane potential and allowed the release of cytochrome c which further leads to apoptosis and cell death. Further to rule out the pathway/mechanism(s) of DOX-mediated cardiac pathologies, the treatment with inhibitors of the classical ROS sources such as NADPH oxidase, Myeloperoxidase, mitochondria and general ROS scavenger (NAC) suggested that ROS via NOX and MPO during DOX-induced toxicity plays a crucial role in cardiomyocytes. The mitochondrial integrity was conserved when the cells were treated with NOX and MPO inhibitors, the cytochrome C release and apoptosis reduced in presence of these inhibitors. Taken together, these results demonstrate that DOX leads to ROS production and oxidative stress in cardiomyocytes which ultimately affects the mitochondrial integrity and functions, most importantly the ROS released via NOX and MPO is critical during DOX-induced cardiotoxicity. - RAS?YAN. All rights reserved.
Serum homocysteine could be used as a predictive marker for chronic obstructive pulmonary disease: A meta-analysis
(Frontiers Media S.A., 2019) Chaudhary, D; Sharma, N; Senapati, Sabyasachi
Background: Serum homocysteine (Hcy) level is inversely related with concentration of folic acid, which is an essential micronutrient for metabolism and energy homeostasis. Serum concentrations of Hcy have been reported to have strong correlation with smoking, which is a major risk factor for pathogenesis of chronic obstructive pulmonary disease (COPD) irrespective of ethnicity and gender. Therefore, we performed a systematic review based meta-analysis to evaluate the overall contribution of Hcy in COPD. Method: Published literature on association of serum Hcy with COPD were obtained through conventional web search and eligible literature were selected based on stringent inclusion/exclusion criteria. Continuous variable data was presented as mean and standard deviation. The variable data was analyzed using RevMan 5 statistical tool to meta-analyze mean differences (MD) with 95 % CI for case-control studies. Result: Four case-control studies met the inclusion criteria for this study. A total of 145 COPD subjects and 107 healthy controls were analyzed. Elevated serum homocysteine concentration was found to induce risk for COPD (MD = 3.05). Conclusion: Molecular role of Hcy in COPD pathogenesis or prognosis is not clear but existing literature suggests that smoking disturbs folic acid metabolism and promotes Hcy accumulation. This study suggested the contribution of Hcy in COPD pathogenesis. However, large scale prospective cohort study and replication studies with more power are warranted to confirm the results. © 2019 Chaudhary, Sharma and Senapati.
Systematic review and meta-analysis confirms significant contribution of surfactant protein D in chronic obstructive pulmonary disease
(Frontiers Media S.A., 2019) Nandy, D; Sharma, N; Senapati, Sabyasachi
Background: Surfactant protein D (SFTPD) is a lung specific protein which performs several key regulatory processes to maintain overall lung function. Several infectious and immune mediated diseases have been shown to be associated with SFTPD. Recent findings have suggested the serum concentration of SFTPD can be used as a diagnostic or prognostic marker for chronic obstructive pulmonary disease (COPD) and acute exacerbation COPD (AECOPD). But these findings lack replication studies from different ethnic populations and meta-analysis, to establish SFTPD as reliable diagnostic or prognostic biomarker for COPD and associated conditions. Methods: We performed systematic literature search based on stringent inclusion and exclusion criteria to identify eligible studies to perform a meta-analysis. Our objective was to assess the predictability of serum SFTPD concentration and SFTPD allelic conformation at rs721917 (C > T) with COPD and AECOPD outcome. These variables were compared between COPD and healthy controls, where mean difference (MD), and odds ratio (OR) were calculated to predict the overall effect size. Review manager (RevMan-v5.3) software was used to analyse the data. Results: A total of eight published reports were included in this study. Comparative serum SFTPD concentration data were extracted from six studies and three studies were evaluated for assessment of genetic marker from SFTPD. Our study identified strong association of elevated serum SFTPD with COPD and AECOPD. Significant association of risk was also observed for "T" allele or "TT" genotype of rs721917 from SFTPD with COPD and AECOPD. Conclusion: Serum concentration and alleleic conformation of SFTPD has a significantly high predictive value for COPD and AECOPD. Thus, these can be tested further and could be applied as a predictive or prognostic marker. © 2019 Frontiers Media S.A. All Rights Reserved.