Article

Acute hyperhomocysteinemia induces microvascular and macrovascular endothelial dysfunction.

Department of Vascular Medicine, University of Munich Medical Center, Munich, Germany.
Archives of Medical Research (impact factor: 1.88). 06/2007; 38(4):411-6. DOI:10.1016/j.arcmed.2007.01.004 pp.411-6
Source: PubMed

ABSTRACT Hyperhomocysteinemia (Hhcy) has been shown to induce endothelial dysfunction due to a decrease in bioavailable nitric oxide (NO) by increased vascular oxidant stress. This can be detected as an impairment of endothelium-dependent vasodilation in conductance arteries, like brachial or coronary arteries. The effect of Hhcy on endothelial function (EF) in small resistance vessels that critically determine organ perfusion, however, has not been studied systematically in humans. Therefore, we simultaneously determined macro- and microvascular EF in 11 healthy subjects before and during acute Hhcy induced by an oral methionine challenge.
Macrovascular EF was determined by measuring endothelium-dependent flow-mediated vasodilation of the brachial artery by vascular ultrasound and microvascular EF by measuring skin perfusion during iontophoresis of acetylcholine using laser Doppler fluxmetry.
Oral methionine significantly increased homocysteine levels by about 5.1-fold. Acute Hhcy leads to a significant decrease in flow-mediated vasodilation of the brachial artery from 8.1 +/- 0.5% to 3.6 +/- 0.6% and to a significant decrease in the ratio of acetylcholine-stimulated vs. baseline laser Doppler flow in the forearm skin (from 9.2 +/- 1.0- to 7.8 +/- 1.3-fold).
Acute Hhcy impairs macro- as well as microvascular (EF) in humans.

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Keywords

11 healthy subjects
 
5.1-fold. Acute Hhcy
 
Acute Hhcy impairs macro-
 
acute Hhcy induced
 
baseline laser Doppler flow
 
bioavailable nitric oxide
 
critically determine organ perfusion
 
endothelium-dependent flow-mediated vasodilation
 
flow-mediated vasodilation
 
induce endothelial dysfunction
 
laser Doppler fluxmetry
 
Macrovascular EF
 
microvascular EF
 
Oral methionine
 
oral methionine challenge
 
significant decrease
 
skin perfusion
 
small resistance vessels
 
vascular oxidant stress
 
vascular ultrasound