Diwesh Chawla - Academia.edu (original) (raw)

Papers by Diwesh Chawla

Zenodo (CERN European Organization for Nuclear Research), Mar 30, 2023

Background: Diabetes mellitus is a multifactorial disease associated with hyperglycemia and incre... more Background: Diabetes mellitus is a multifactorial disease associated with hyperglycemia and increased risk of progression of vascular complications. Stimulation of insulin secretion by the incretin hormone glucagon-like peptide 1 (GLP-1) has been found to be diminished in hyperglycemia. We hypothesized that this impairment is due to defect at the receptor level induced by the diabetic state. Inflammatory markers like TNF-α and IL-6 plays a potential role in the pathogenesis of T2DM. Therefore, the present study aims to evaluate whether GLP-1 plays a role in the development of T2DM by modulating the balance between pro and anti-inflammatory markers. Material and methods: A total of 60 subjects were recruited in this study among them 30 were T2DM cases and 30 were healthy controls. m-RNA expression and protein level of GLP-1 receptor, TNF-α and IL-6 in peripheral blood lymphocytes were determined by real time PCR and ELISA respectively. Results: We observed plasma level of GLP-1 was significantly lower in diabetic subjects while serum level of IL-6 and TNF-α were significantly higher level in diabetic subjects (p < 0.05). We found significant down regulation of GLP-1 receptor m-RNA expression in diabetic subjects while expression level of IL-6 and TNF-α were 5.8 and 4 folds respectively higher in diabetic subjects. We found significant negative correlation of m-RNA expression of GLP-1 with protein level while IL-6 and TNF-α showed significant positive correlation. Conclusion: Inflammation plays an important role in the pathogenesis of diabetes mellitus and low GLP-1 levels may promote expression of inflammatory markers due to lack of anti-inflammatory effects of GLP-1

Indian Journal of Endocrinology and Metabolism, 2023

Diabetes Research and Clinical Practice, Mar 1, 2014

The study was designed to evaluate the association of À374T/A and À429T/C polymorphism in the pro... more The study was designed to evaluate the association of À374T/A and À429T/C polymorphism in the promoter region and Gly82Ser polymorphism in exon 3 region of RAGE gene with diabetic vascular complications in Indian population. Methods: We screened 603 subjects which includes 176 healthy controls, 140 type 2 diabetes mellitus (T2DM) subjects without any vascular complications (DM), 152 T2DM subjects with microvascular complications (DM-micro) and 135 T2DM subjects with macrovascular complications (DM-macro) for À374T/A, À429T/C and Gly82Ser polymorphisms of RAGE gene. DNA isolated from the enrolled subjects were genotyped by PCR-RFLP. Logistic regression analysis was used to evaluate the association of single nucleotide polymorphisms (SNPs). Results: The À429 T/C and Gly82Ser RAGE polymorphisms were found to be significantly associated with the development of macrovascular and microvascular complications, respectively, in T2DM subjects while À374A allele showed reduced risk towards the development of macrovascular complications. Further, À429T/C, À374T/A and Gly82Ser haplotype analysis revealed association of CTG haplotype with development of macrovascular complications while haplotype TAG was observed to be significantly protective towards development of macrovascular complications in T2DM subjects (OR = 0.617, p = 0.0202). Conclusions: Our data indicates significant association of RAGE SNPs and haplotypes with vascular complications in North Indian T2DM subjects.

Microvascular Research, Sep 1, 2014

Vascular complications are the major causes of morbidity and mortality in diabetic subjects. Inte... more Vascular complications are the major causes of morbidity and mortality in diabetic subjects. Interaction of advanced glycation end products (AGEs) with their receptor (RAGE) induces signal transduction that culminates in vascular complications. Therefore, in the present study we investigated the dependence of RAGE expression on circulating AGEs and evaluated the outcome of AGE-RAGE interaction by the oxidative stress and nature of vascular complications in type 2 diabetes mellitus (T2DM) patients. RAGE expression was determined by quantitative real-time PCR and western blotting, serum AGEs were estimated by ELISA and spectrofluorometry and oxidative stress markers namely protein carbonyl (PCO), advanced oxidation protein products (AOPP) and lipid peroxidation (MDA) were assayed spectrophotometerically in 75 T2DM patients (DM without vascular complication n=25; DM with microvascular complications n=25; DM with macrovascular complications n=25) and 25 healthy controls. Serum AGE level was significantly higher in diabetic patients having vascular complications as compared to T2DM without complications (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). RAGE m-RNA expression level in PBMCs assayed by quantitative real time PCR was four times higher in diabetic subjects without vascular complications while DM patients having microvascular and macrovascular complications showed 12 fold and 8 fold higher RAGE m-RNA expression respectively compared to healthy controls. Circulating AGE level showed significant positive correlation with RAGE m-RNA expression and oxidative stress markers. AGE-mediated exacerbation of RAGE expression may contribute to oxidative stress generation that plays a key role in pathogenesis of vascular complications in diabetes.

GSC biological and pharmaceutical sciences, Mar 30, 2023

Integrative food, nutrition and metabolism, 2019

Diabetes Mellitus (DM) is one of the major health problems of the current century. It is associat... more Diabetes Mellitus (DM) is one of the major health problems of the current century. It is associated with accelerating advanced glycation end products (AGEs) formation and accumulation in the circulating blood and various tissues. AGEs, also accelerate the expression of its receptor i.e. receptor for AGEs (RAGE) and plays a pivotal role in the development and progression of diabetic vascular complications through various mechanisms. Hyperglycemia mediated reactive oxygen species generation can induce oxidative stress through four major mechanisms including the polyol pathway, AGEs formation, activation of protein kinase c isoforms and the hexosamine pathway. Therapeutic interventions may improve the clinical course of patients having diabetes and its associated vascular complications by reducing the AGEs levels. This review summarizes the recent update on the role of AGE-RAGE mediated mechanisms in the development of diabetic vascular complications.

Gene, Sep 1, 2013

Background and aims: Sustained interaction of advanced glycation end products (AGEs) with their r... more Background and aims: Sustained interaction of advanced glycation end products (AGEs) with their receptor RAGE and subsequent signaling plays an important role in the development of diabetic complications. Genetic variation of RAGE gene may be associated with the development of vascular complications in type 2 diabetes mellitus (T2DM). Objectives: The present study aimed to explore the possible association of RAGE gene polymorphisms namely − 374T/A, − 429T/C and G82S with serum level of AGEs, paraoxonase (PON1) activity and macro-vascular complications (MVC) in Indian type 2 diabetes mellitus patients (T2DM). Methods: A total of 265 diabetic patients, including DM without any complications (n = 135), DM-MVC (n = 130) and 171 healthy individuals were enrolled. Genotyping of RAGE variants were assessed by polymerase chain reaction-restriction fragment length polymorphism. Serum AGEs were estimated by ELISA and fluorometrically. and PON1 activity was assessed spectrophotometrically. Results: Of the three examined SNPs, association of −429T/C polymorphism with MVC in T2DM was observed (OR = 3.001, p = 0.001) in the dominant model. Allele 'A' of −374T/A polymorphism seems to confer better cardiac outcome in T2DM. Patients carrying C allele (−429T/C) and S allele (G82S) had significantly higher AGE levels. −429T/C polymorphism was also found to be associated with low PON1 activity. Interaction analysis revealed that the risk of development of MVC was higher in T2DM patients carrying both a CC genotype of −429T/C polymorphism and a higher level of AGEs (OR = 1.343, p = 0.040). Conclusion: RAGE gene polymorphism has a significant effect on AGE level and PON1 activity in diabetic subjects compared to healthy individuals. Diabetic patients with a CC genotype of −429T/C are prone to develop MVC, more so if AGE levels are high and PON1 activity is low.

Molecular Cytogenetics, 2014

Indian Journal of Endocrinology and Metabolism

Zenodo (CERN European Organization for Nuclear Research), Jan 30, 2023

Reactive nitrogen species such as peroxynitrite anion (ONOO-), nitrogen oxide radical (NO.) may l... more Reactive nitrogen species such as peroxynitrite anion (ONOO-), nitrogen oxide radical (NO.) may lead to nitrotyrosine formation by oxidative nitration of tyrosine. Nitrotyrosine is considered as an important marker to estimate the severity of biological oxidative damage. Therefore, in the present study, we evaluated a reverse phase-high performance liquid chromatography (RP-HPLC) method to improve the sensitivity and specificity of the nitrotyrosine estimation. The mobile phase used in the present study was methanol (pH 4.7) and 0.1% phosphoric acid (60:40%). The standard serial dilutions were injected onto the HPLC column (C-18) at a flow rate of 1 ml/min mobile phase with a time window of 6 min. The results were monitored on the Diode Array detector at wavelength 210 nm. The evaluation and quantification of output signals were made on the Chromelion software version 6.80 which controls the whole liquid chromatography system. The same standard serial dilutions were monitored spectrophotometrically at 210nm. We found the standard curves were linear over the concentration range of 0.3 to 20 ng/ml for both RP-HPLC with UV detector (r 2 = 0.997) and spectrophotometric (r 2 = 0.999) methods. In spectrophotometric method, only four standard points were detected out of seven and represented on a straight line, this shows the spectrophotometric method was unable to measure less than 2.5 ng/ml concentration. On the other hand, in RP-HPLC method, all the seven standards were lying on a straight line and HPLC machine can detect up to 1ng/ml or 1pg/µl. The present study established the highly specific, sensitive, accurate and cost-effective RP-HPLC with UV detector method for nitrotyrosine estimation.

GSC Biological and Pharmaceutical Sciences

Diwesh Chawla*1; Ashok Kumar Tripathi2 ; Meera Sikka3 1Central Research Laboratory, Multi-discipl... more Diwesh Chawla*1; Ashok Kumar Tripathi2 ; Meera Sikka3 1Central Research Laboratory, Multi-disciplinary Research Unit, University College of Medical Sciences (University of Delhi) and G.T.B. Hospital, Dilshad Garden, Delhi-110095, India. 2Biochemistry and Immunology Laboratory, Department of Biochemistry, University College of Medical Sciences (University of Delhi) and G.T.B. Hospital, Dilshad Garden, Delhi-110095, India. 3Department of Pathology, University College of Medical Sciences (University of Delhi) and G.T.B. Hospital, Dilshad Garden, Delhi-110095, India. Correspondence to: Diwesh Chawla, Central Research Laboratory, Multi-disciplinary Research Unit, University College of Medical Sciences (University of Delhi) and G.T.B. Hospital, Dilshad Garden, Delhi 110095, India. Email: diweshchawla@yahoo.co.in Chapter 1 Advances in Biochemistry & Applications in Medicine

Integrative Food, Nutrition and Metabolism, 2019

Drug Metabolism and Pharmacokinetics, 2019

Lithocholic acid (LCA), a toxic bile acid, is conjugated to glycine to form glycolithocholic acid... more Lithocholic acid (LCA), a toxic bile acid, is conjugated to glycine to form glycolithocholic acid (G-LCA) or to taurine to form taurolithocholic acid (T-LCA). Sulfotransferase 2A1 (SULT2A1) not only plays an important role in LCA sulfonation, but it is also responsible for the metabolism of many drugs, including abiraterone, a steroidal anti-androgen drug used in prostate cancer treatment. Therefore, we determined whether steroidal anti-androgens, namely abiraterone acetate (pro-drug), abiraterone (active metabolite), and galeterone, inhibit SULT2A1-catalyzed sulfonation of LCA, G-LCA, and T-LCA, as quantified by ultra-high performance liquid chromatography-tandem mass spectrometry. Sulfonation of LCA, G-LCA, and T-LCA by human liver cytosol exhibited substrate inhibition, with apparent K m of 0.6 ± 0.3, 1.8 ± 0.4, and 1.1 ± 0.3 mM, and V max of 143 ± 32, 803 ± 113, and 324 ± 52 pmol/min/mg protein, respectively. G-LCA sulfonation yielded the greatest catalytic efficiency (V max /K m), followed by T-LCA sulfonation and LCA sulfonation. Abiraterone acetate, abiraterone, and galeterone inhibited human liver cytosolic LCA, G-LCA, and T-LCA sulfonation in a similar pattern, with average IC50 values of 0.4-1.1 mM. Enzyme

International journal of gynecological cancer : official journal of the International Gynecological Cancer Society, 2018

Ovarian cancer is associated with a high relapse rate and is the fifth leading cause of cancer de... more Ovarian cancer is associated with a high relapse rate and is the fifth leading cause of cancer deaths in women. The genetic profile of a tumor is responsible for deciding response to chemotherapeutic agents. In this study, we investigate the relation between survivin and p53 expression and response to chemotherapeutic agents of primary cultures of ovarian cancer cells established from ascitic fluid. Ascitic fluid and Dulbecco's modified Eagle medium was mixed in equal proportion in culture flasks and incubated to establish primary culture. The cells were treated with different combinations of carboplatin and paclitaxel with and without survivin small interfering RNA transfection. Cell survival was estimated by MTT assay. Survivin and p53 expression was quantified by real-time polymerase chain reaction. Out of 19 ascitic fluid samples, 13 primary cultures of ovarian cancer cells were established. The half maximal inhibitory concentration doses of carboplatin (≥70 μg/mL) and pacli...

Journal of biochemical and molecular toxicology, 2018

This study investigates the exposure of lead-induced reactive oxygen species (ROS) generation, DN... more This study investigates the exposure of lead-induced reactive oxygen species (ROS) generation, DNA damage, and apoptosis and also evaluates the therapeutic intervention using antioxidants in human renal proximal tubular cells (HK-2 cells). Following treatment of HK-2 cells with an increasing concentration of lead nitrate (0-50 μM) for 24 h, the intracellular ROS level increased whereas the GSH level decreased significantly in a dose-dependent manner. Comet assay results revealed that lead nitrate showed the ability to increase the levels of DNA strand breaks in HK-2 cells. Lead exposure also induced apoptosis through caspase-3 activation at 30 μg/mL. Pretreatment with N-acetylcysteine (NAC) and tannic acid showed a significant ameliorating effect on lead-induced ROS, DNA damage, and apoptosis. In conclusion, lead induces ROS, which may exacerbate the DNA damage and apoptosis via caspase-3 activation. Additionally, supplementation of antioxidants such as NAC and tannic acid may be us...

Gene, Jan 30, 2018

The proinflammatory cytokine interleukin-1beta (IL-1β) is a key mediator of inflammation which af... more The proinflammatory cytokine interleukin-1beta (IL-1β) is a key mediator of inflammation which affects cell proliferation and differentiation. IL-1β is considered to contribute to the pathophysiology of rheumatoid arthritis (RA). Polymorphisms in cytokine genes are highly influenced by ethnicity. Hence, in this study polymorphism of the IL1B-511(C/T) within promoter region was analyzed by using polymerase chain reaction-restriction fragment length Polymorphism (PCR-RFLP) in 187 RA patients and 214 controls. The prevalence of different genotypes and allelic frequency distribution was compared in RA patients and controls. Levels of inflammatory markers and serum levels of IL-1β were estimated by ELISA The serum inflammatory markers levels were significantly higher in RA patients as compared to controls (RF=127.3±21.3U/mL, Anti-CCP=17.8±8.3U/mL, CRP=17.86±7.1mg/L and IL-1β=21.25±4.19pg/mL in RA patients p<0.01). The frequency of heterozygous mutant (C/T) and homozygous mutant (T/T) ...

International Journal of Gynecologic Cancer, 2017

ObjectiveOvarian cancer is the seventh leading cause of cancer death worldwide. This is mainly du... more ObjectiveOvarian cancer is the seventh leading cause of cancer death worldwide. This is mainly due to late diagnosis and high rate of relapse and resistance following chemotherapy. In the present study, we describe simple and cost-effective method to establish primary culture from ascitic fluid and solid tumor obtained from epithelial ovarian carcinoma patient, which may provide a better tool for in vitro testing of drug sensitivity and designing individualized treatment protocol.MethodsComplete Dulbecco modified Eagle medium (DMEM) was prepared by supplementing DMEM with 10% fetal bovine serum and antibiotics (ciprofloxacin and amphotericin B). Establishment of primary culture of ovarian cancer cells from ascites fluid and solid tumor was done by using complete DMEM media.ResultsPrimary cultures of ovarian cancer cells were established from ascitic fluid and solid tumor tissue. Of the 7 ascitic fluid samples, we were able to establish 5 primary cultures of ovarian cancer cells. All...

Pharmaceutica Analytica Acta, 2015

Despite plenty of sunlight, vitamin D deficiency (VDD) in India is an epidemic. 50-90% population... more Despite plenty of sunlight, vitamin D deficiency (VDD) in India is an epidemic. 50-90% populations among all age groups are associated with VDD. Among the common methods (RIA, immunoassay etc.) available for vitamin D estimation, the analytical method like HPLC is considering as a gold standard. In the proposed study, we have developed a RP-HPLC method for the estimation of vitamin D3 with greater precision and accuracy. Separation was achieved on C18 column in isocratic mode using two different mobile phases i.e. acetonitrile: methanol (method I) and methanol: water with 0.1% formic acid (method II). The column was maintained at 40 °C and the mobile phase was pumped at flow rate of 0.4 mL min −1. The detection of eluent was carried out at λ max 265 nm. Retention time of vitamin D3 for method I and II was found to be 7.14 and 7.01 minutes, respectively, with R 2 >0.99. The standard curves were linear over the concentration range of 0.5-5 ng mL −1. The LOD and LOQ values for vitamin D 3 for method I and II were found to be 1.64, 5.02 and 1.10, 3.60 ng mL −1 , respectively. The percentage recovery was found to be 69-79% and 75-87% for method I and II, respectively. The % RSD of intra and inter-day precision of method I was found <2 and <7%, whereas, for method II, <2 and <4% respectively. In conclusion, method II showed greater precision and accuracy and also cost effective, therefore, it can be used for vitamin D 3 estimation at laboratory scale.