The vessel wall is an active, integrated organ composed of endothelial, smooth-muscle, and fibroblast cells coupled to each other in a complex autocrine-paracrine set of interactions. The vasculature is capable of sensing changes within its milieu, integrating these signals by intercellular communication, and changing itself through the local production of mediators that influence structure as well as function. Vascular remodeling is an active process of structural alteration that involves changes in at least four cellular processes -- cell growth, cell death, cell migration, and production or degradation of extracellular matrix -- and is dependent on a dynamic interaction between locally . . .