Endothelium-dependent Vasodilation in Normotensive Subjects with a Familial History of Essential Hypertension and in Young Subjects with Borderline Hypertension

Objective: To investigate if young normotensive subjects with a familial history of essential hypertension (FHH) or young borderline-hypertensive (BHT) subjects have a defect endothelial function. Methods: Fifteen young (26 &#45 4 years) healthy normotensive (115 &#45 8/71 &#45 6 mmHg) subjects with a FHH, 31 matched healthy normotensive subjects without FHH and seven BHT (143 &#45 12/92 &#45 2 mmHg), otherwise healthy, young males underwent evaluation of endothelium-dependent vasodilation (EDV) and endothelium-independent vasodilation (EIDV), by means of local intra-arterial infusions of methacholine (MCh, evaluating EDV) and sodium nitroprusside (SNP, evaluating EIDV) in the forearm. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Results : Although there was no significant difference between normotensive subjects with and without a FHH regarding FBF during vasodilation induced by MCh or SNP, the subjects with a FHH presented a significantly suppressed endothelial function index, calculated as the ratio between EDV and EIDV, when compared to subjects without FHH (1.04 &#45 0.15 vs. 1.24 &#45 0.23, p < 0.01). Also in the group of BHT subjects, the endothelial function index was suppressed (1.01 &#45 0.18, p < 0.01), in this case due to a significantly attenuated EDV ( p < 0.05), when compared to male subjects without a FHH. Conclusion: The present findings suggest an early occurrence of endothelial dysfunction in the development of essential hypertension.