Angiotensin II Type 1 Receptor Antagonism Improves Hypercholesterolemia-Associated Endothelial Dysfunction

Abstract

ObjectiveObjective—Hypercholesterolemia-induced angiotensin II type 1 (AT1) receptor overexpression is thought to be a key event in the development of endothelial dysfunction. Methods and Results—The effect of a 6-week treatment with the AT1 receptor antagonist candesartan (16 mg/d) on endothelial function and serum inflammation markers was compared with the effect of treatment with placebo or the calcium channel antagonist felodipine (5 mg/d) in 47 hypercholesterolemic patients (low density lipoprotein cholesterol >160 mg/dL). Endothelial function was assessed by measurement of forearm blood flow (FBF) by venous occlusion plethysmography. FBF during reactive hyperemia was significantly improved by candesartan, whereas felodipine and placebo exerted no effect. Nitroglycerin-induced vasorelaxation and basal FBF were not altered significantly. Blood pressure and cholesterol levels were not affected significantly by any drug. Serum concentrations of 8-isoprostane, monocyte chemoattractant protein-1, and soluble intercellular adhesion molecule-1 were significantly reduced by candesartan treatment but not by placebo or felodipine (ELISA assays). Levels of high-sensitivity C-reactive protein and tumor necrosis factor-&agr; were not altered significantly by any treatment. Conclusions—These data suggest that AT1 receptor antagonism improves endothelial function during hypercholesterolemia and that this applies not only to endothelium-dependent vasodilatation but also to oxidative stress and events involved in monocyte attraction and adhesion. AT1 receptor blockade may potentially represent a novel approach for the prevention of vascular dysfunction associated with hypercholesterolemia that is independent of lipid-lowering and blood pressure–lowering interventions.