Influence of hypertension and of antihypertensive drugs on the arterial wall.
This paper reviews some of the experimental data regarding the effects of hypertension and antihypertensive drugs on the arterial wall. Hypertension induces major changes in both the arterial media and intima. Experimental studies from our own and other laboratories have demonstrated that medial smooth muscle cells in several forms of hypertension in the rat undergo hypertrophy and nuclear polyploidy which contribute, along with connective tissue alterations, to a large increase in medial mass. Our studies in the deoxycorticosterone/salt-hypertensive rat indicate that such changes may be difficult to regress, despite prolonged control of the hypertension. In the arterial intima, major alterations in the endothelium are induced by hypertension in association with increase in arterial permeability. Marked enhancements of adherence of circulating white blood cells to the endothelium can also be demonstrated along with penetration of blood monocytes and their accumulation in the subendothelial space. Hypertension also appears to stimulate the migration and proliferation of smooth muscle cells in the intima, and evidence is beginning to accumulate that endogenous growth factors within the artery may be involved in this process. Essentially all of the intimal changes which we have observed as a result of arterial hypertension are also present with cholesterol feeding although intimal accumulation of lipid and formation of atherosclerotic plaques do not occur with hypertension alone. On the other hand, in hypercholesterolemic animals, hypertension appears to act as a promoter of atherogenesis. Several antihypertensive drugs may influence the atherosclerotic process. The experimental data regarding the effects of beta blockers and calcium antagonists in the cholesterol-fed rabbit are discussed. Though of considerable interest, the clinical relevance of the findings remains uncertain.
Chobanian
A V
AV
Cardiovascular Institute, Boston University School of Medicine, Mass.
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001158:Arteries / Q000187:drug effects / Q000503:physiopathology*; D001161:Arteriosclerosis / Q000503:physiopathology; D006973:Hypertension / Q000503:physiopathology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000503:physiopathology; D011817:Rabbits; D051381:Rats
D000959:Antihypertensive Agents