L-arginine improves endothelium-dependent vasodilation in hypercholesterolemic humans.

Abstract

Endothelium-dependent vasodilation is impaired in hypercholesterolemia, even before the development of atherosclerosis. The purpose of this study was to determine whether infusion of L-arginine, the precursor of the endothelium-derived relaxing factor, nitric oxide, improves endothelium-dependent vasodilation in hypercholesterolemic humans. Vascular reactivity was measured in the forearm resistance vessels of 11 normal subjects (serum LDL cholesterol = 2.76±0.10 mmol/liter) and 14 age-matched patients with hypercholesterolemia (serum LDL cholesterol = 4.65±0.36 mmol/ liter, P < 0.05). The vasodilative response to the endothelium-dependent vasodilator, methacholine chloride, was depressed in the hypercholesterolemic group, whereas endothelium-independent vasodilation, induced by nitroprusside, was similar in each group. Intravenous administration of L-arginine augmented the forearm blood flow response to methacholine in the hypercholesterolemic individuals, but not in the normal subjects. L-arginine did not alter the effect of nitroprusside in either group. D-arginine had no effect on forearm vascular reactivity in either group. It is concluded that endothelium-dependent vasodilation is impaired in hypercholesterolemic humans. This abnormality can be improved acutely by administration of L-arginine, possibly by increasing the synthesis of endothelium-derived relaxing factor. (J. Clin.

Blood flow response in individuals with incomplete spinal cord injuries

“…Abnormal vascular control has not been reported previously in SCI patients. However, abnormal vascular control has been seen in a variety of conditions including: aging, 14,15 race, 16,17 hypercholesterolemia, 18,19 obesity, 20 diabetes 21 ± 24 and examples of muscle deconditioning after 14 ± 20 days of bed rest. 24 ± 27 Furthermore, untrained individuals have been shown to have poor orthostatic tolerance when compared to trained individuals.…”

Endothelial arginase: A new target in atherosclerosis

“…Several groups demonstrated that acute and chronic supplementation of L-arginine improves endothelial vasodilator responses in cholesterol fed animals and in patients with hypercholesterolemia and atherosclerosis [20][21][22][23]. Following these early studies, numerous studies with supplemental Larginine therapy have been conducted in animal models and in humans; however, no consistent results can be achieved [24••].…”

Endothelial dysfunction in atherosclerotic mice: improved relaxation by combined supplementation with L‐arginine‐tetrahydrobiopterin and enhanced vasoconstriction by endothelin

“…It has been well documented that endothelium-dependent vasodilation is impaired in both animal models of atherosclerosis (Freiman et al, 1986;Kolodgie et al, 1990) and in atherosclerotic human coronary arteries (Bossaler et al, 1987;FoÈ rstermann et al, 1988;Zeiher et al, 1991). In addition, risk factors for the development of atherosclerosis such as hypercholesterolemia are associated with impaired endothelial function (Creager et al, 1992).…”