The effect of L-arginine on microvascular reactivity in normotensive subjects with a family history of hypertension

Abstract

Background : An increasing number of studies support the hypothesis that endothelial dysfunction due to reduced availability of nitric oxide plays a key role in initiation, development and progression of essential hypertension. The aim of our study was to determine whether the ingestion of L-arginine actually improves microvascular function in normotensive subjects with a family history of hypertension. Methods : 30 normotensive healthy men, aged 20–30 years, were divided into two groups according to the family history of hypertension. We measured ECG, heart rate, systolic and diastolic arterial pressure, cardiac output, stroke volume, total peripheral resistance (Task Force Monitor) and laser Doppler (LD) flux in the microvessels of the skin on the forearm at rest, before and after the administration of 0.9 g L-arginine. The endothelium-dependent vasodilation was assessed by iontophoresis of acetylcholine and the endothelium-independent vasodilation by iontophoresis of sodium nitroprusside. Results : After the ingestion of L-arginine the heart rate and the cardiac output statistically significantly decreased in both groups (paired t-test, p < 0.05). Arterial pressure did not change significantly. Stroke volume decreased and total peripheral resistance increased only in the group of subjects with a family history of hypertension (paired t-test, p < 0.05) The ingestion of L-arginine in predisposed normotensive subjects acutely improved the endothelium-dependent vasodilation (Dunnett’s test, p < 0.05), which is consistent with the assumption that endothelial dysfunction is already present in these subjects. Conclusions : In subjects with a family history of hypertension L-arginine improved endothelial function. This justifies L-arginine as a potential agent for the prevention and/or treatment of arterial hypertension.