Endothelium and acute coronary syndromes.

The vascular endothelium is a dynamic endocrine organ that regulates contractile, secretory, and mitogenic activities in the vessel wall and hemostatic processes within the vascular lumen. Risk factors for atherosclerosis such as cigarette smoking, hypertension, and increased serum lipid concentrations impair endothelial function and lead to the development of atherosclerotic vessels, which cause acute coronary syndromes. Atherosclerotic vessels progress from scattered foam cells to complex lesions with a lipid core and fibrous cap. Factors that weaken and cause the rupture of the fibrous cap will expose circulating blood products to the procoagulant materials in the lipid core. Thrombosis and subsequent remodeling of the unstable plaque may be catastrophic or clinically silent depending on the degree of vascular occlusion and availability of collateral blood flow. Evidence is presented that supports the view that endothelial dysfunction is an early marker of atherosclerosis and an important contributor to the atherogenic process.