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Papers by Vidhya Srinivasan
“OXIDATIVE STRESS MARKERS IN TYPE 2 DIABETES MELLITUS”, 2024
Insulin resistance and high blood glucose are hallmarks of type 2 diabetes mellitus (T2DM), a se... more Insulin resistance and high blood glucose are hallmarks of type 2
diabetes mellitus (T2DM), a serious global health concern. In the
pathogenesis of T2DM, oxidative stress—a mismatch between
antioxidant defenses and reactive oxygen species (ROS)—is a major
factor. The mechanisms causing oxidative stress and its clinical
consequences are highlighted in this review, which offers a thorough
overview of oxidative stress markers in T2DM. We classify oxidative
stress according to its origins, pathways, impacted biomolecules, and
related illnesses. We stress the significance of keeping an eye on
indicators of oxidative stress, including glutathione (GSH), catalase,
advanced oxidation protein products (AOPPs), protein carbonyls,
malondialdehyde (MDA), and superoxide dismutase (SOD).
Comprehending these indicators is crucial for formulating focused
treatment approaches to reduce oxidative stress and enhance clinical
results in individuals with T2DM.
Indian Journal of Medical Research, 2019
Background & objectives: Amino acids are general nutrients having anti-diabetic property. The... more Background & objectives: Amino acids are general nutrients having anti-diabetic property. The present study was undertaken to investigate the mechanism of anti-diabetic effects of amino acids in human visceral adipocyte cells in high glucose environment. Methods: Experiments were carried out in human visceral adipocytes. Adiponectin (APN) siRNAs were designed using Ambion tools. APN mRNA expression was quantified using real-time polymerase chain reaction, and protein level was studied using ELISA. AMP-activated kinase (AMPK) activity was measured and glucose uptake by 2-deoxyglucose uptake method. Results: Amino acids (proline and phenylalanine) exposure to adipocytes significantly (P <0.01) increased APN mRNA by 1.5-folds when compared to control whereas proline increased APN secretion by 10.6-folds (P <0.01), phenylalanine by 12.7-folds (P <0.001) and alanine by 6.3-folds (P <0.01). Free amino acid-induced AMPK activity and glucose uptake were decreased with the transient knockdown of APN. Interpretation & conclusions: Antidiabetic effect of the tested amino acids was exhibited by increased glucose uptake through the AMPK pathway by an APN-dependent mechanism in human visceral adipocytes. This should be tested and confirmed in in vivo system. Newer treatment modalities with amino acids which can enhance glucose uptake and APN secretion can be developed as drug for treating both diabetes and obesity.
Purpose of this study was to measure adiponectin (APN) and to compare with already known players ... more Purpose of this study was to measure adiponectin (APN) and to compare with already known players of retinopathy namely VEGF, PEDF and IGF-1 in vitreous and plasma of patients with PDR. Methods: Plasma and vitreous samples of 26 patients with PDR who underwent vitrectomy were analyzed for APN, PEDF, IGF-1 and VEGF by ELISA. Among these 19 patients were underwent laser treatments prior to vitrectomy. Disease matched control samples were collected from 11 Macular Hole (MH) patients. The study was done with prior approval from Institution Ethics Board. Results: The vitreous samples from PDR patients (n=29) showed increased level of APN (91.1 ng/ml, p<0.0001) when compared to 0.32 ng/ml in vitreous from MH patients (n=11). PDR patients who underwent LASER treatment showed 3 fold increase in vitreous APN (113.5ng/ml, p < 0.03), and a significant decrease in VEGF levels (p < 0.002) than those who had not. Vitreous APN, VEGF and IGF -1 levels were significantly elevated in patients...
Indian Journal of Ophthalmology, 2009
The tear ascorbate owing to its high concentration, functions as an eff ective antioxidant agains... more The tear ascorbate owing to its high concentration, functions as an eff ective antioxidant against the oxidative damage of cornea. Contact lens wearers (CLW) are prone to oxidative stress due to the lens-induced hypoxic conditions. A pilot study was done to compare the tear ascorbic acid level and the total antioxidant capacity give as in normal and CLW. Materials and Methods: In this study 21 CLW (Mean age 23 ± 3 years; M-2, F-19), who were daily wear users, with duration of wear not more than four years, along with age-matched 28 controls (Mean age 28 ± 3; M-15, F-13) were recruited in the study for collection of reß ex tears using Schirmer's strip. Ascorbic acid in tears was determined using high-performance liquid chromatography (HPLC), total antioxidant capacity (TAC) and total protein assay by spectrophotometric analysis. Results: CLW showed no signiÞ cant change in the tear ascorbic acid levels (0.4 ± 0.26 mM) compared to the control subjects (0.61 ± 0.59 mM). The amount of ascorbic acid in tears did not correlate with the TAC or the total protein of the tears. The mean TAC in CLW was 0.69 ± 0.16 mM, with a total protein of 1.35 ± 0.46 mg/ml while in controls it was 0.7 ± 0.18 mM and 1.21 ± 0.47 mg/ml respectively. Conclusions: Soft contact lens wear did not show any signiÞ cant change in tear ascorbic acid, TAC and total protein levels compared to controls.
Indian journal of pharmacology
This study was carried out to identify the role of adiponectin (APN) in modulating the expression... more This study was carried out to identify the role of adiponectin (APN) in modulating the expression of vascular endothelial growth factor (VEGF) and pigment epithelial-derived factor (PEDF) in relation to ocular angiogenesis. Human retinal pigment epithelial cell lines (ARPE-19) were cultured in Dulbeco's minimum essential medium with 10% fetal bovine serum (FBS) and exposed to varying concentrations of recombinant adiponectin (5-5 ng/ml) for 1 h. Analysis of VEGF and PEDF mRNA was done by reverse transcriptase and further quantified by quantitative polymerase chain reaction. VEGF and PEDF protein expression were studied using enzyme-linked immune sorbent assay (ELISA). Unpaired Student's t-test was used to analyze the significance. P < 0.05 was accepted as statistically significant. ARPE cells exposed to APN showed decreased expression of VEGF mRNA, protein whereas PEDF protein is unaltered and PEDF mRNA was increased. Our in vitro study on ARPE exposed to APN showed a neg...
Journal of cancer research and therapeutics
We studied the expression of elastic fiber in esophageal squamous cell carcinoma tissue in North-... more We studied the expression of elastic fiber in esophageal squamous cell carcinoma tissue in North-eastern Indian population. Archival paraffin embedded 40 esophageal carcinoma specimens were retrieved for the study. Only smokers were included in the study. Verhoeff's stain for elastic fiber was performed to demonstrate elastic fiber with positive and negative control. A total of 28 (70%) tissue specimens was found to be positive for elastic fiber. Elastosis in esophageal carcinoma may be due to smoking. Further studies are required to rule out the etiology.
International journal of pharma and bio sciences, 2014
Recently we have reported the elevated levels of Adiponectin (APN) in proliferative diabetic reti... more Recently we have reported the elevated levels of Adiponectin (APN) in proliferative diabetic retinopathy (PDR) vitreous in comparison to macular hole. It has been assumed that APN may get exudated into vitreous from circulation but no experimental proof has been shown so far. Therefore we set out to determine the origin of APN in the vitreous.Donor eye balls were used to extract RNA and protein for real time PCR, western blotting. Five micron retinal sections were done for immunofluorescence and immunohistochemistry. Primary retinal epithelial and endothelial cells were isolated from donor eye balls aged below 50 years.APN exerts its function through two receptors, AdipoR1 and AdipoR2. Interestingly we identified the expression of APN, AdipoR1 and AdipoR2 mRNA transcripts in all ocular tissues by quantitative PCR. Immunofluorescence and western blot analysis demonstrated the presence of APN and its receptors AdipoR1, AdipoR2 in all ocular tissues. AdipoR1 and AdipoR2 were distribute...
Adiponectin (APN) is a protein hormone having anti-diabetic and anti-inflammatory properties. Its... more Adiponectin (APN) is a protein hormone having anti-diabetic and anti-inflammatory properties. Its presence in ocular tissues has been postulated, to have escaped from circulation due to the dysfunctional blood brain barrier (BRB) in retinal diseases. The purpose of this study is to understand the origin of intraocular APN and its receptors, precisely measure vitreous APN in proliferative diabetic retinopathy (PDR) and macular hole (MH), study its role in disease pathogenesis of PDR and to unravel the therapeutic potential of APN. All human studies were done with approval from Institutional Review Board (IRB) and consent of the participants. Tissues derived from donor eye balls were used for qPCR, immuno staining, western blot analysis for localisation and expression studies. Vitreous samples were obtained from patients who underwent vitrectomy surgery for PDR and MH and used for measurement of APN by ELISA. Vitreous amino acids were estimated by HPLC. Role of APN in the pathogenesis...
Indian Journal of Clinical Biochemistry, 2015
ABSTRACT Heme oxygenase is an enzyme having three isoforms and is responsible for breakdown of he... more ABSTRACT Heme oxygenase is an enzyme having three isoforms and is responsible for breakdown of heme into iron, carbon monoxide and bilirubin. There is no study related to heme oxygenase levels in human vitreous. So in this study our objectives were to measure heme oxygenase (HO) enzyme activity in vitreous and plasma of patients with proliferative diabetic retinopathy (PDR) and compare with the HO levels of patients with macular hole (MH). All protocols were approved by the Institution’s Ethics Board. Blood and vitreous samples were collected from 15 patients with PDR and 11 from macular hole who underwent vitrectomy surgery. HO enzyme activity was measured in vitreous and plasma samples by spectrophotometric method. In the PDR group, vitreous HO was 8.03 ± 1.95 pmol of bilirubin/mg protein which is significantly higher when compared to the MH group, 0.67 ± 0.2 pmol of bilirubin/mg protein. However, there was no difference in their HO activity in plasma, between the groups. Total Heme oxygenase enzyme activity is elevated in vitreous of PDR. Vitreous HO activity positively correlated with already reported adiponectin levels in these patients.
Aim: This study was carried out to identify the role of adiponectin (APN) in modulating the expre... more Aim: This study was carried out to identify the role of adiponectin (APN) in modulating the expression of vascular endothelial growth factor (VEGF) and pigment epithelial-derived factor (PEDF) in relation to ocular angiogenesis. Materials and Methods: Human retinal pigment epithelial cell lines (ARPE-19) were cultured in Dulbeco's minimum essential medium with 10% fetal bovine serum (FBS) and exposed to varying concentrations of recombinant adiponectin (5–5 ng/ml) for 1 h. Analysis of VEGF and PEDF mRNA was done by reverse transcriptase and further quantifi ed by quantitative polymerase chain reaction. VEGF and PEDF protein expression were studied using enzyme-linked immune sorbent assay (ELISA). Statistical Analysis: Unpaired Student's t-test was used to analyze the signifi cance. P < 0.05 was accepted as statistically signifi cant. Results: ARPE cells exposed to APN showed decreased expression of VEGF mRNA, protein whereas PEDF protein is unaltered and PEDF mRNA was increased. Conclusion: Our in vitro study on ARPE exposed to APN showed a negative correlation with VEGF levels. Thus indicating the protective role for APN in angiogenesis-related diseases. KEY WORDS: KEY WORDS: Adiponectin, pigment epithelium derived factor, proliferative diabetic retinopathy, vascular endothelial growth factor
“OXIDATIVE STRESS MARKERS IN TYPE 2 DIABETES MELLITUS”, 2024
Insulin resistance and high blood glucose are hallmarks of type 2 diabetes mellitus (T2DM), a se... more Insulin resistance and high blood glucose are hallmarks of type 2
diabetes mellitus (T2DM), a serious global health concern. In the
pathogenesis of T2DM, oxidative stress—a mismatch between
antioxidant defenses and reactive oxygen species (ROS)—is a major
factor. The mechanisms causing oxidative stress and its clinical
consequences are highlighted in this review, which offers a thorough
overview of oxidative stress markers in T2DM. We classify oxidative
stress according to its origins, pathways, impacted biomolecules, and
related illnesses. We stress the significance of keeping an eye on
indicators of oxidative stress, including glutathione (GSH), catalase,
advanced oxidation protein products (AOPPs), protein carbonyls,
malondialdehyde (MDA), and superoxide dismutase (SOD).
Comprehending these indicators is crucial for formulating focused
treatment approaches to reduce oxidative stress and enhance clinical
results in individuals with T2DM.
Indian Journal of Medical Research, 2019
Background & objectives: Amino acids are general nutrients having anti-diabetic property. The... more Background & objectives: Amino acids are general nutrients having anti-diabetic property. The present study was undertaken to investigate the mechanism of anti-diabetic effects of amino acids in human visceral adipocyte cells in high glucose environment. Methods: Experiments were carried out in human visceral adipocytes. Adiponectin (APN) siRNAs were designed using Ambion tools. APN mRNA expression was quantified using real-time polymerase chain reaction, and protein level was studied using ELISA. AMP-activated kinase (AMPK) activity was measured and glucose uptake by 2-deoxyglucose uptake method. Results: Amino acids (proline and phenylalanine) exposure to adipocytes significantly (P <0.01) increased APN mRNA by 1.5-folds when compared to control whereas proline increased APN secretion by 10.6-folds (P <0.01), phenylalanine by 12.7-folds (P <0.001) and alanine by 6.3-folds (P <0.01). Free amino acid-induced AMPK activity and glucose uptake were decreased with the transient knockdown of APN. Interpretation & conclusions: Antidiabetic effect of the tested amino acids was exhibited by increased glucose uptake through the AMPK pathway by an APN-dependent mechanism in human visceral adipocytes. This should be tested and confirmed in in vivo system. Newer treatment modalities with amino acids which can enhance glucose uptake and APN secretion can be developed as drug for treating both diabetes and obesity.
Purpose of this study was to measure adiponectin (APN) and to compare with already known players ... more Purpose of this study was to measure adiponectin (APN) and to compare with already known players of retinopathy namely VEGF, PEDF and IGF-1 in vitreous and plasma of patients with PDR. Methods: Plasma and vitreous samples of 26 patients with PDR who underwent vitrectomy were analyzed for APN, PEDF, IGF-1 and VEGF by ELISA. Among these 19 patients were underwent laser treatments prior to vitrectomy. Disease matched control samples were collected from 11 Macular Hole (MH) patients. The study was done with prior approval from Institution Ethics Board. Results: The vitreous samples from PDR patients (n=29) showed increased level of APN (91.1 ng/ml, p<0.0001) when compared to 0.32 ng/ml in vitreous from MH patients (n=11). PDR patients who underwent LASER treatment showed 3 fold increase in vitreous APN (113.5ng/ml, p < 0.03), and a significant decrease in VEGF levels (p < 0.002) than those who had not. Vitreous APN, VEGF and IGF -1 levels were significantly elevated in patients...
Indian Journal of Ophthalmology, 2009
The tear ascorbate owing to its high concentration, functions as an eff ective antioxidant agains... more The tear ascorbate owing to its high concentration, functions as an eff ective antioxidant against the oxidative damage of cornea. Contact lens wearers (CLW) are prone to oxidative stress due to the lens-induced hypoxic conditions. A pilot study was done to compare the tear ascorbic acid level and the total antioxidant capacity give as in normal and CLW. Materials and Methods: In this study 21 CLW (Mean age 23 ± 3 years; M-2, F-19), who were daily wear users, with duration of wear not more than four years, along with age-matched 28 controls (Mean age 28 ± 3; M-15, F-13) were recruited in the study for collection of reß ex tears using Schirmer's strip. Ascorbic acid in tears was determined using high-performance liquid chromatography (HPLC), total antioxidant capacity (TAC) and total protein assay by spectrophotometric analysis. Results: CLW showed no signiÞ cant change in the tear ascorbic acid levels (0.4 ± 0.26 mM) compared to the control subjects (0.61 ± 0.59 mM). The amount of ascorbic acid in tears did not correlate with the TAC or the total protein of the tears. The mean TAC in CLW was 0.69 ± 0.16 mM, with a total protein of 1.35 ± 0.46 mg/ml while in controls it was 0.7 ± 0.18 mM and 1.21 ± 0.47 mg/ml respectively. Conclusions: Soft contact lens wear did not show any signiÞ cant change in tear ascorbic acid, TAC and total protein levels compared to controls.
Indian journal of pharmacology
This study was carried out to identify the role of adiponectin (APN) in modulating the expression... more This study was carried out to identify the role of adiponectin (APN) in modulating the expression of vascular endothelial growth factor (VEGF) and pigment epithelial-derived factor (PEDF) in relation to ocular angiogenesis. Human retinal pigment epithelial cell lines (ARPE-19) were cultured in Dulbeco's minimum essential medium with 10% fetal bovine serum (FBS) and exposed to varying concentrations of recombinant adiponectin (5-5 ng/ml) for 1 h. Analysis of VEGF and PEDF mRNA was done by reverse transcriptase and further quantified by quantitative polymerase chain reaction. VEGF and PEDF protein expression were studied using enzyme-linked immune sorbent assay (ELISA). Unpaired Student's t-test was used to analyze the significance. P < 0.05 was accepted as statistically significant. ARPE cells exposed to APN showed decreased expression of VEGF mRNA, protein whereas PEDF protein is unaltered and PEDF mRNA was increased. Our in vitro study on ARPE exposed to APN showed a neg...
Journal of cancer research and therapeutics
We studied the expression of elastic fiber in esophageal squamous cell carcinoma tissue in North-... more We studied the expression of elastic fiber in esophageal squamous cell carcinoma tissue in North-eastern Indian population. Archival paraffin embedded 40 esophageal carcinoma specimens were retrieved for the study. Only smokers were included in the study. Verhoeff's stain for elastic fiber was performed to demonstrate elastic fiber with positive and negative control. A total of 28 (70%) tissue specimens was found to be positive for elastic fiber. Elastosis in esophageal carcinoma may be due to smoking. Further studies are required to rule out the etiology.
International journal of pharma and bio sciences, 2014
Recently we have reported the elevated levels of Adiponectin (APN) in proliferative diabetic reti... more Recently we have reported the elevated levels of Adiponectin (APN) in proliferative diabetic retinopathy (PDR) vitreous in comparison to macular hole. It has been assumed that APN may get exudated into vitreous from circulation but no experimental proof has been shown so far. Therefore we set out to determine the origin of APN in the vitreous.Donor eye balls were used to extract RNA and protein for real time PCR, western blotting. Five micron retinal sections were done for immunofluorescence and immunohistochemistry. Primary retinal epithelial and endothelial cells were isolated from donor eye balls aged below 50 years.APN exerts its function through two receptors, AdipoR1 and AdipoR2. Interestingly we identified the expression of APN, AdipoR1 and AdipoR2 mRNA transcripts in all ocular tissues by quantitative PCR. Immunofluorescence and western blot analysis demonstrated the presence of APN and its receptors AdipoR1, AdipoR2 in all ocular tissues. AdipoR1 and AdipoR2 were distribute...
Adiponectin (APN) is a protein hormone having anti-diabetic and anti-inflammatory properties. Its... more Adiponectin (APN) is a protein hormone having anti-diabetic and anti-inflammatory properties. Its presence in ocular tissues has been postulated, to have escaped from circulation due to the dysfunctional blood brain barrier (BRB) in retinal diseases. The purpose of this study is to understand the origin of intraocular APN and its receptors, precisely measure vitreous APN in proliferative diabetic retinopathy (PDR) and macular hole (MH), study its role in disease pathogenesis of PDR and to unravel the therapeutic potential of APN. All human studies were done with approval from Institutional Review Board (IRB) and consent of the participants. Tissues derived from donor eye balls were used for qPCR, immuno staining, western blot analysis for localisation and expression studies. Vitreous samples were obtained from patients who underwent vitrectomy surgery for PDR and MH and used for measurement of APN by ELISA. Vitreous amino acids were estimated by HPLC. Role of APN in the pathogenesis...
Indian Journal of Clinical Biochemistry, 2015
ABSTRACT Heme oxygenase is an enzyme having three isoforms and is responsible for breakdown of he... more ABSTRACT Heme oxygenase is an enzyme having three isoforms and is responsible for breakdown of heme into iron, carbon monoxide and bilirubin. There is no study related to heme oxygenase levels in human vitreous. So in this study our objectives were to measure heme oxygenase (HO) enzyme activity in vitreous and plasma of patients with proliferative diabetic retinopathy (PDR) and compare with the HO levels of patients with macular hole (MH). All protocols were approved by the Institution’s Ethics Board. Blood and vitreous samples were collected from 15 patients with PDR and 11 from macular hole who underwent vitrectomy surgery. HO enzyme activity was measured in vitreous and plasma samples by spectrophotometric method. In the PDR group, vitreous HO was 8.03 ± 1.95 pmol of bilirubin/mg protein which is significantly higher when compared to the MH group, 0.67 ± 0.2 pmol of bilirubin/mg protein. However, there was no difference in their HO activity in plasma, between the groups. Total Heme oxygenase enzyme activity is elevated in vitreous of PDR. Vitreous HO activity positively correlated with already reported adiponectin levels in these patients.
Aim: This study was carried out to identify the role of adiponectin (APN) in modulating the expre... more Aim: This study was carried out to identify the role of adiponectin (APN) in modulating the expression of vascular endothelial growth factor (VEGF) and pigment epithelial-derived factor (PEDF) in relation to ocular angiogenesis. Materials and Methods: Human retinal pigment epithelial cell lines (ARPE-19) were cultured in Dulbeco's minimum essential medium with 10% fetal bovine serum (FBS) and exposed to varying concentrations of recombinant adiponectin (5–5 ng/ml) for 1 h. Analysis of VEGF and PEDF mRNA was done by reverse transcriptase and further quantifi ed by quantitative polymerase chain reaction. VEGF and PEDF protein expression were studied using enzyme-linked immune sorbent assay (ELISA). Statistical Analysis: Unpaired Student's t-test was used to analyze the signifi cance. P < 0.05 was accepted as statistically signifi cant. Results: ARPE cells exposed to APN showed decreased expression of VEGF mRNA, protein whereas PEDF protein is unaltered and PEDF mRNA was increased. Conclusion: Our in vitro study on ARPE exposed to APN showed a negative correlation with VEGF levels. Thus indicating the protective role for APN in angiogenesis-related diseases. KEY WORDS: KEY WORDS: Adiponectin, pigment epithelium derived factor, proliferative diabetic retinopathy, vascular endothelial growth factor