Endothelial nitric oxide synthase Glu298Asp (G894T) gene polymorphism in coronary artery disease patients with type 2 diabetes mellitus

Aims: Endothelial dysfunction is thought to be a significant risk factor for cardiovascular disease. This study determined the role of endothelial nitric oxide synthase (eNOS) Glu298Asp polymorphism and intergenotypic variation of plasma nitric oxide (NO) levels in coronary artery disease (CAD) patients with type 2 diabetes mellitus (DM). Methods: This case-control study included 28 documented CAD patients with type 2 DM and 32 nondiabetic patients with CAD. Fifty healthy volunteers without any major cardiovascular risk factors served as controls. NO was estimated by modified Griess method. The eNOS gene polymorphism was studied by amplifying DNA by PCR and digesting with BanII restriction enzyme. Restriction fragment length polymorphism was studied by using a gel documentation system. Results: The genotype frequencies for Glu298Asp (GT) genotype were 10.71% in diabetic CAD patients, 28.1% in non-diabetic CAD patients and 12% in controls. The T allele frequency was higher in the nondiabetic CAD group (14%) as compared with the diabetic CAD (5.4%) and control group (6%). NO level was significantly lower in non-diabetic CAD patients (10.25 mmol/L) but not in diabetic CAD patients (13.89 mmol/L) as compared to controls (16.78 mmol/L). Conclusion: Glu298Asp polymorphism is not the mediator of increased incidence of CAD in diabetic patients. (C) 2012 Diabetes India. Published by Elsevier Ltd. All rights reserved.