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Background and aim Insulin resistance plays a crucial role in the pathogenesis of type 2 diabetes and cardiovascular diseases. Recently, paraoxonase-1(PON1) is reported to have an ability to reduce insulin resistance by promoting glucose transporter-4 (GLUT-4) expression in vitro. Single nucleotide polymorphism (SNP) in PON1 is associated with variability in enzyme activity and concentration. Based on this we aimed to investigate the association of PON1 (Q192R and L55M) polymorphisms with the risk of developing insulin resistance in adult South Indian population. Methods Two hundred and eighty seven (287) Type 2 diabetes patients and 293 healthy controls were enrolled in this study. All the study subjects were genotyped for PON1 (Q192R and L55M) missense polymorphisms using polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) method. Fasting serum insulin level was measured by ELISA. Results The distribution of QR/RR and LM/MM genotypes were significantly higher in type 2 diabetes patients compared with healthy controls. Moreover, the R and M alleles were significantly associated with type 2 diabetes with an Odds Ratio of 1.68 (P < 0.005) and 2.24 (P < 0.005) respectively. SNP 192 Q > R genotypes were found to be significantly associated with higher BMI, cholesterol, triglycerides, LDL, fasting serum insulin and HOMA-IR. Further, the mutant allele or genotypes of PON1 L55M were associated with higher BMI, triglycerides, VLDL, fasting serum insulin and HOMA-IR among adult type 2 diabetes patients. Conclusion PON1 (Q192R and L55M) polymorphisms may play a crucial role in pathogenesis and susceptibility of insulin resistance thus leads to the development of type 2 diabetes in South Indian population. [ABSTRACT FROM AUTHOR]

Abstract Background and aim Oxidative stress and impaired insulin secretion is an underlying major risk factor for the development of type 2 diabetes (T2D). Uncoupling protein-2 (UCP2) is involved in the regulation of reactive oxygen species production, insulin secretion, and lipid metabolism. Based on this we aimed to find an association of UCP2 (G-866A) polymorphism with the risk of T2D in South Indian population. Methods A total of 318 T2D patients and 312 controls were enrolled in this study. All the study subjects were genotyped for UCP2 (G-866A) polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Fasting blood glucose, HbA1c, serum lipid profile, systolic and diastolic blood pressure were measured by standard biochemical methods. Fasting serum insulin level was measured by ELISA. Results In UCP2 (G-866A) polymorphism, the distribution of GA (46%) and AA (14%) genotypes were significantly higher in T2D patients than the healthy controls. The frequency of GA and AA genotypes have high risk towards the development of T2D with an Odds Ratio (OR) of 1.55 (P = 0.01) and 2.04 (P = 0.01) respectively. Moreover, SNP-866 G>A allele was found to be significantly associated with T2D (OR = 1.48, P = 0.001, 95% CI = 1.16–1.88). Further, the UCP2 AA genotype showed significantly decreased level of insulin by the reduction in pancreatic β-cell function in T2D patients. Conclusion UCP2 (G-866A) polymorphism may play a crucial role in the pathogenesis of insulin secretion thus leads to the development of T2D. Highlights • UCP2 (G-866A) polymorphism involved in the pathogenesis of type 2 diabetes. • GA and AA genotypes in the promoter region of UCP2 associated with decreased level of insulin in the studied population. • An individual's carrying 'A' allele in UCP2 (-866) may require earlier insulin therapy after diagnosis of the disease. • Identification of UCP2 polymorphism could help to early diagnosis of type 2 diabetes. [ABSTRACT FROM AUTHOR]

Background: Potassium ion (K(+)) plays an essential role in maintaining the electrical potential across the plasma membrane of cells. An abnormal serum K(+) level is associated with increased risk of ventricular arrhythmia and sudden cardiac death (SCD) and these patients are generally prescribed with furosemide and potassium chloride (KCl). We explored the association between the use of these drugs and the risk of SCD by analyzing biochemical parameters and proteomic changes., Materials and Methods: The rats were administered with furosemide and KCl and their effect was analyzed by studying cardiac and oxidative markers, electrolyte content and histopathology. Two-dimensional gel electrophoresis (2-DE) and electrospray ionization-mass spectrometry were performed to investigate the LV proteomic changes., Results: Furosemide and KCl treatments showed significant effect on physiological and biochemical parameters, and LV histopathology of experimental rats. Proteomic analysis indicated 17 differentially expressed proteins. Among them, eight protein spots were identified using peptide mass fingerprinting. In furosemide-treated group, four proteins were upregulated and two proteins were downregulated when compared to 2-DE proteomic profile of control. While in KCl-treated rats, seven proteins were found downregulated., Conclusion: [corrected] The present study revealed the differential expression of proteins by furosemide and KCl treatment. Thus, the results suggest that the use of these drugs leads to proteomic alteration, which involve in cardiac conductivity that might increase the risk of SCD.

Hyperglycemia is independently related with excessive morbidity and mortality in cardiovascular disorders. L-Arginine-nitric oxide (NO) pathway and the involvement of NO in modulating nuclear factor-E2-related factor-2 (Nrf2) signaling were well established. In the present study we investigated, whether L-arginine supplementation would improve the myocardial antioxidant defense under hyperglycemia through activation of Nrf2 signaling. Diabetes was induced by alloxan monohydrate (90 mg kg(-1) body weight) in rats. Both non-diabetic and diabetic group of rats were divided into three subgroups and they were administered either with L-arginine (2.25%) or L-NAME (0.01%) in drinking water for 12 days. Results showed that L-arginine treatment reduced the metabolic disturbances in diabetic rats. Antioxidant enzymes and glutathione levels were found to be increased in heart left ventricles, thereby reduction of lipid peroxidation by L-arginine treatment. Heart histopathological analysis further validates the reversal of typical diabetic characteristics consisting of alterations in myofibers and myofibrillary degeneration. qRT-PCR studies revealed that L-arginine treatment upregulated the transcription of Akt and downregulated NF-κB. Notably, transcription of eNOS and Nrf2 target genes was also upregulated, which were accompanied by enhanced expression of Nrf2 in left ventricular tissue from diabetic and control rats. Under these findings, we suggest that targeting of eNOS and Nrf2 signaling by L-arginine supplementation could be used as a potential treatment method to alleviate the late diabetic complications., (Copyright © 2012 Elsevier Inc. All rights reserved.)