Expression of urotensin-II in human coronary atherosclerosis

The vasoactive peptide urotensin-II (U-II) is best known for its ability to regulate peripheral vascular and cardiac contractile function in vivo, and recent in vitro studies have suggested a role for the peptide in the control of vascular remodeling by inducing smooth muscle proliferation and fibroblast-mediated collagen deposition. Therefore, U-II may play a role in the etiology of atherosclerosis. In the present study we sought to determine the expression of U-II in coronary arteries from patients with coronary atherosclerosis and from normal control subjects, using immunohistochemistry and in situ hybridization. In normal coronary arteries, there was little expression of U-II in all types of cells. In contrast, in patients with coronary atherosclerosis, endothelial expression of U-II was significantly increased in all diseased segments (P < 0.05). Greater expression of U-II was noted in endothelial cells of lesions with subendothelial inflammation or fibrofatty lesion compared with that of endothelial cells underlined by dense fibrosis or minimal intimal thickening. Myointimal cells and foam cells also expressed U-II. In most diseased segments, medial smooth muscle cells exhibited moderate expression of U-II. These findings demonstrate upregulation of U-II in endothelial, myointimal and medial smooth muscle cells of atherosclerotic human coronary arteries, and suggest a possible role for U-II in the pathogenesis of coronary atherosclerosis.