ABSTRACT
The vascular system serves as more than a simple passive conduit for blood flow. Rather, cellular elements in the vessel wall actively participate in the homeostatic functions of the vasculature that maintain vascular integrity and sustain normal circulation. The vascular endothelium, in particular, plays a critical role in the regulation of vessel physiology through elaboration of antiatherogenic paracrine factors that maintain vascular tone, inhibit platelet activation and inflammatory cell adhesion, promote fibrinolysis, and modulate vascular cell proliferation. Under pathological conditions, phenotypic changes occur in endothelial cells that impair normal homeostasis and promote a vasospastic, prothrombotic, and proinflammatory milieu, thus supporting atherothrombogenesis and clinical cardiovascular events (1). In this chapter we will briefly summarize normal homeostatic functions of blood vessels. We will then discuss the role of vascular dysfunction in mechanisms of atherogenesis and acute coronary syndromes and consider therapeutic implications.
