Atherosclerosis: cellular aspects and potential interventions.

The pathogenesis of atherosclerosis has been extensively studied and the cellular aspects increasingly characterized. This review will focus on the basic pathology, presumed cellular events, cellular interactions, cell-lipid relationships, and potential therapies of atherosclerosis. Fatty streaks, fibrous plaques, and complicated plaques are the pathologic hallmarks of atherosclerosis. These lesions insidiously progress, and symptoms appear to develop when the plaque luminal surface destabilizes. The major cellular contributors to plaque development are monocytes/macrophages, endothelial cells, smooth muscle cells, and, to a lesser degree, lymphocytes and platelets. They interact in a complicated fashion. Growth factors and cytokines produced by these cells are also of great importance for cell-cell interaction. Hemodynamic factors contribute to atherogenesis at preferential sites within the arterial vasculature, presumably by effects on the cellular mechanisms. Hyperlipidemia, especially elevations of total and LDL-cholesterol, has been well characterized as an atherosclerotic risk factor. Cellular modification of LDL-cholesterol, primarily by oxidation, leads to more rapid uptake by macrophage-derived foam cells, enhancing plaque growth by this and other mechanisms. These observations may unify the cellular and lipid contributors to atherogenesis. Therapies directed at the cellular contributors to atherosclerosis are being assessed. Dietary n-3 fatty acid supplementation reduces the extent of experimental atherosclerosis, and human studies are in progress. Many potential cellular effects of n-3 fatty acids have been demonstrated. Other potential therapies for atherosclerosis that probably work at the cellular level include calcium channel blockers, antioxidants, and heparinoids. An exciting new era of atherosclerosis research and, hopefully, therapy has dawned, as knowledge about its cellular basis accrues.