P-135: Obesity, insulin resistance, cardiac structure, and renin-angiotensin system genes in essential hypertension

Abstract

The aim of the present study was to determine if genetic variants of the renin-angiotensin system genes contribute to the presence of obesity, glucose intolerance, hyperinsulinemia and left ventricular hypertrophy (LVH) in essential hypertensive (EH) patients.

We examined 156 patients (the mean age 49±8yrs) with mild to moderate EH recruited from the general population of the outpatient hypertensive clinic. Left ventricular mass was measured by echocardiography and left ventricular mass index (LVMI) was estimated. Standard oral glucose tolerance test (OGT) with a parallel measurement of fasting, 30, 60, 90, and 120 min insulin and glucose levels was performed. The areas under the curves (AUC) of glucose and insulin were calculated. Subjects were genotyped for I/D polymorphism of ACE gene, A1166C polymorphism of the AT1 receptor gene, M235T polymorphism of angiotensinogen gene and G/A-6 polymorphism of its promoter region.

Genotype distribution of the sample obeyed Hardy-Weinberg equilibrium and was comparable to that reported previously for hypertensive individuals. In groups of patients with different genotype variants the body mass index (BMI), fasting insulin, and AUCs of insulin and glucose were comparable. Neither I/D ACE-gene polymorphism, nor AT1-receptor gene and angiotensinogen gene polymorphisms were associated with LVH. No significant gene-gene interactions contributing to insulin resistance and LVH in EH patients have been found. At the same time, the LVMI level was strongly influenced by BMI (r=0.31, p<0.01) and fasting insulin level (r=0.24, p<0.05).

In conclusion, we failed to find any association between distinct genotypes of the renin-angiotensin system genes and glucose metabolism as well as with LVH in hypertensive patients. Alternatively, hyperinsulinemia and obesity appears to be important determinants of LVH in EH.

left ventricular hypertrophy, insulin resistance, genetics

© American Journal of Hypertension, Ltd. 2001