Hyperhomocyst(e)inemia Is Associated With Impaired Endothelium-Dependent Vasodilation in Humans

TLDR

Hyperhomocyst(e)inemia is a risk factor for atherosclerosis and is common in the elderly. The study aimed to determine whether hyperhomocyst(e)inemia impairs endothelium‑dependent vasodilation in humans. High‑resolution vascular ultrasonography measured flow‑mediated and nitroglycerin‑mediated vasodilation in 26 hyperhomocyst(e)inemic elderly subjects versus 15 matched controls. Hyperhomocyst(e)inemic subjects showed significantly reduced flow‑mediated vasodilation (3.7 % vs. 8.1 %; P =.004) with no difference in nitroglycerin‑mediated dilation.

Abstract

Background Hyperhomocyst(e)inemia is a risk factor for atherosclerosis and is prevalent in the elderly. The objective of this study was to determine whether hyperhomocyst(e)inemia is associated with impaired endothelium-dependent vasodilation in humans. Methods and Results High-resolution vascular ultrasonography was used to study endothelium-dependent and -independent vasodilation in a nonatherosclerotic peripheral conduit artery of 26 elderly hyperhomocyst(e)inemic subjects and 15 age- and sex-matched subjects with normal homocysteine levels. Flow-mediated, endothelium-dependent (nitric oxide–mediated) vasodilation was assessed by measuring the percent change in brachial artery diameter during reactive hyperemia. Endothelium-independent vasodilation was assessed after the administration of 0.4 mg sublingual nitroglycerin. Endothelium-dependent vasodilation was significantly impaired in the hyperhomocyst(e)inemic subjects compared with control subjects (3.7±0.6% versus 8.1±1.2%; P =.004), whereas endothelium-independent vasodilation was not different between the two groups (10.1±1.6% versus 9.3±1.5%; P =NS). In a linear regression analysis with serum homocysteine concentration, folic acid, age, sex, cholesterol (serum total, LDL, or HDL cholesterol), mean arterial blood pressure, use of antihypertensive medication, and baseline brachial artery diameter included as covariates, serum homocysteine concentration emerged as the only significant predictor of flow-mediated vasodilation. Conclusions These data indicate that hyperhomocyst(e)inemia is associated with impaired endothelium-dependent vasodilation in humans and suggest that the bioavailability of nitric oxide is decreased in hyperhomocyst(e)inemic humans. ( . 1997;95:1119-1121.)