Susceptibility of diabetics with superoxide dismutase gene 2 polymorphism to cardiovascular complications

Abstract

Introduction: Diabetes mellitus is the most important cause for vascular diseases of heart and brain. The major factor in the development of diabetic complications is oxidative stress. Superoxide dismutases (SODs) are the enzymes which play a primary role against oxidative stress. A polymorphism C/T substitution producing TT genotype in superoxide dismutase 2 gene causes impaired targeting of the SOD 2 enzyme, resulting in reduced activity of the enzyme inside mitochondria. This can lead to increased oxidative stress in these patients making them susceptible to cardiovascular complications Aim: Our study is performed to analyse if there is increased susceptibility of diabetics with SOD2 gene polymorphism to cardiovascular complications and to assess if this SOD2 polymorphism causes reduced SOD activity. Materials and Methods: 30 cases of diabetics with cardiovascular disease, 30 cases of diabetics without cardiovascular disease and 30 healthy controls are included in the study. Genotype analysis by PCR and RFLP and serum superoxide dismutase activity is measured by spectrophotometer. Results: TT genotype is more frequently distributed and Serum SOD activity is reduced among diabetics with CVD compared to diabetics without CVD and controls ,which shows an increased risk of cardiovascular complications among diabetics with SOD2(GCT/GTT) gene polymorphism. Conclusion: TT genotype is an independent risk factor for the development of cardiovascular complications in diabetes. Patients with TT genotype have reduced level of serum superoxide dismutase that may cause increased oxidative stress, the main mechanism for development of cardiovascular complications in diabetes.