Platelet nitric oxide production and IR: relation with obesity and hypertriglyceridemia

Three NOS isoforms are responsible for nitric oxide production in various tissues. Endothelial constitutive NOS is expressed in vascular endothelium and in platelets, contributing to vascular tone regulation and platelet aggregation. The aim of the present work was to examine eNOS polymorphism, to find a correlation with platelet NO production and degree of insulin resistance (IR) in non-diabetic subjects and in patients affected by type 2 diabetes.

Seventy-one non-diabetic subjects and 37 patients affected by Type 2 diabetes were recruited. The subjects were subdivided into 3 groups as cut-off for the definition of an insulin resistant state: IR non-diabetic subjects, insulin sensitive subjects, and insulin-resistant patients affected by Type 2 diabetes. Plasma glyco-metabolic parameters, platelet nitric oxide production, endothelial nitric oxide synthase (eNOS) gene polymorphism were measured in all subjects enrolled. Significant differences between groups were found in BMI, fasting glycaemia, fructosamine and HbA(1c), triglycerides and HDL cholesterol levels. Evaluating all the subjects, platelet NO production was significantly related with BMI, waist circumference, and triglycerides concentrations, thus suggesting an association between increased platelet NO production, obesity and hypertriglyceridemia, independent of the degree of insulin-resistance.

The modified platelet NO synthesis does not seem to be due to eNOS Glu298Asp polymorphism, while it can be hypothesized that it is caused by an iNOS induction, present in obesity, hypertriglyceridemia and in type 2 diabetes.