Endocrine Abstracts

Introduction: There is growing body of evidence that insulin resistance and hyperinsulinemia can contribute to development and accelerate the progression of atherogenesis of large arteries. However, an association between the severity of angiographically confirmed atherosclerotic lesions of coronary arteries and the levels of insulin in the plasma in patients with ischemic heart disease (IHD) without history of diabetes mellitus or dysglycemia was not properly examined. The aim of the study was to investigate the plasma insulin levels in patients with clinically and angiographically confirmed IHD and different severity of atherosclerotic lesions of coronary arteries.

Materials and methods: We examined 78 patients with IHD without history of diabetes mellitus or impaired glucose tolerance (aged 61.5+9.2 years, BMI – 29.5+5.1 kg/m²). All studied patients underwent stress test, coronaroventriculography and oral glucose tolerance test. The blood was collected at fasting and 2 h after glucose ingestion. Insulin levels were determined in all blood samples by radioimmunosorbent method (ELISA) along with plasma glucose measurements.

Results: All studied patients with IHD were divided to three groups according to the number of occluded coronary arteries (with atherosclerotic lesions located in 1, 2 and 3 coronary arteries, respectively). None of the studied patients had type 2 diabetes mellitus or impaired glucose tolerance based on the results of oral glucose tolerance test. The mean plasma glucose levels were not significantly different between all three groups of patients studied either at fasting or 2 h after ingestion of glucose during oral glucose tolerance test. Also, there was no elevation of glycated hemoglobin levels in all patients studied. It was found that fasting plasma insulin levels were significantly elevated in patients with IHD and multiple atherosclerotic lesions which expanded to 2 or 3 coronary arteries compared to patients with 1 occluded artery. The insulin levels at fasting were 19.1+1.16, 24.1+2.28, 25.0+1.64 μMU/ml in patients with 1, 2 or 3 occluded coronary arteries, respectively, P<0.05 for comparisons between insulin levels in subjects with 2 and 3 damaged arteries compared to 1 artery. The similar trend was found in plasma insulin levels 2 h after administration of glucose.

Conclusions: Hyperinsulinemia as the reflection of insulin resistance is related to the more severe angiographically documented atherosclerotic lesions of coronary arteries in patients with IHD. We may speculate that hyperinsulinemia can play a role in the progression of atherosclerosis of coronary arteries.