Review of preclinical data of calcium channel blockers and atherosclerosis.

A variety of animal models have been used to determine whether calcium channel blockers exert an inhibitory effect on atherosclerotic lesion formation. These models include the cholesterol-fed rabbit, in which the lesions resemble the fatty-streak stage of atherosclerotic lesion development in humans. Diet-induced atherosclerosis in monkeys is also used and, in this case, the lesions resemble those found in humans, both in pathology and distribution. Other models involve mechanical injury superimposed on cholesterol feeding. Cellular and subcellular preparations are being used to investigate the mechanisms involved in the antiatherosclerotic activity of the calcium channel blockers. The ability of calcium channel blockers to slow atherosclerotic lesion formation is a class effect that is independent of their blood pressure-lowering effect, and occurs without any significant change in the plasma lipid profile. It is accompanied by a reduction in vessel wall cholesterol and calcium and is maintained over prolonged periods of treatment. The mechanisms that may be involved include inhibition of smooth muscle cell proliferation and migration, slowed platelet aggregation, restructuring of cholesterol-enriched cell membranes, enhanced gene expression for low-density lipoprotein receptor protein, inhibition of growth factor release, slowed calcium uptake, and restoration of endothelium-dependent relaxation.