Role of endothelin-1 in hypertension and vascular disease

Endothelin-1 (ET-1) is a powerful vasoconstrictor peptide and regulator of blood flow that plays an important role in blood pressure (BP) elevation in some models of experimental hypertension such as DOCA-salt rat, DOCA-salt-treated spontaneously hypertensive rats (SHR), stroke-prone SHR, Dahl salt-sensitive rats, angiotensin II-infused rats, and one-kidney, one-clip Goldblatt rats, but not in SHR, two-kidney, one-clip hypertensive rats, transgenic (mREN2)27 rats, or Nω-nitro-L-arginine methyl ester chronically treated rats. In those models of hypertension in which ET-1 plays a vasoconstrictor role, ET-1 was shown to be overexpressed in the vessel walls, or BP has been lowered by administration of ETA/B- and ETA-selective receptor antagonists. In these experimental models, endothelin receptor antagonists also regressed vascular growth and inflammation, and improved endothelial dysfunction. Hypertensive rats treated with endothelin antagonists were protected from stroke and renal injury. In hypertensive rats without generalized vascular overproduction of ET-1, expression of ET-1 was often enhanced in intramyocardial coronary arteries, suggesting a role of ET in myocardial ischemia in hypertension. Moderate-to-severe hypertensive patients presented enhanced expression of preproET-1 mRNA in the endothelium of subcutaneous resistance arteries, suggesting that this stage of hypertension may respond particularly well to endothelin antagonism. In some hypertensive patients, exaggerated vascular responses to ET-1 were found. Hypertensive patients with coronary artery disease have increased arterial expression of ET-1. Increased plasma levels of immunoreactive ET have been described in African Americans. ET-1 plays an important role in atherosclerosis, for which hypertension is an important risk factor, and in ischemic heart disease and stroke. Endothelin-1 may also be involved in other forms of vascular disease, including pulmonary hypertension, after angioplasty restenosis, after allograft vasculopathy, and vasculitis. Thus, ET-1 may participate in vascular damage in cardiovascular disease and in BP elevation in experimental models and in human hypertension. Endothelin antagonists could become effective disease-modifying agents in different forms of cardiovascular disease.