Vascular renin-angiotensin system and vascular protection.

Vascular angiotensin plays an important role in the long-term regulation of the blood vessel function and structure. Angiotensin stimulates vascular smooth-muscle cell growth via the induction of protooncogene and autocrine growth factor gene expressions. In hypertension, atherosclerosis and restenosis, vascular angiotensin activity is increased and participates in the pathobiology of these vascular diseases. Experimental data demonstrate that angiotensin-converting enzyme inhibitors can prevent vascular hypertrophy of hypertension, attenuate atherosclerosis, and inhibit neointimal hyperplasia of restenosis. Taken together, the data show that pharmacologic blockade of the vascular renin-angiotensin system may result in vascular protection. Ongoing clinical trials (MERCATOR, QUIET) will address the relevance of these experimental observations in clinical therapy.