Relationship between Endothelial Nitric Oxide Synthase, Insulin Resistance and Macrovascular Disease in Patients with Acute Myocardial Infarction

OBJECTIVE: To explore the relationship between endothelial nitric oxide synthase (eNOS) activity, insulin resistance and macrovascular disease in patients with acute myocardial infarction (AMI). METHODS: AMI patients were grouped according to the presence (group A, n = 49) or absence (group B, n = 48) of macrovascular disease. A healthy control group was also recruited (group C, n = 43). eNOS activity and nitric oxide (NO), endothelin-1 (ET-1), fasting plasma glucose and fasting insulin levels were compared across groups. The homeostasis model assessment of insulin resistance (HOMA- IR) was calculated in each participant and correlations between biochemical parameters were determined. RESULTS: eNOS and NO levels were significantly lower in group A compared with the other groups. Conversely, ET-1 levels and the HOMA-IR were significantly higher in group A. eNOS activity and NO levels were significantly lower, and ET-1 levels and HOMA-IR were significantly higher, in group B compared with controls. Across the groups there were inverse correlations in AMI patients between eNOS and HOMAIR, NO and HOMA-IR, eNOS and ET-1, and NO and ET-1, and positive correlations between eNOS and NO, regardless of whether macrovascular disease was present. CONCLUSION: There is a close relationship between eNOS activity and the development of insulin resistance and macrovascular disease in AMI patients.