Angiogenesis.

Angiogenesis, the growth and proliferation of blood vessels from existing vascular structures, is tightly regulated in adult tissues, and abnormalities in angiogenesis are associated with a number of pathologic states. Strategies designed to promote angiogenesis to treat disorders of inadequate tissue perfusion, such as occurs in coronary artery and peripheral vascular disease, have led to the area of therapeutic angiogenesis. Approaches to block angiogenesis are actively being explored to treat diseases that range from arthritis to cancer. This article will review some of the basic concepts of vascular development and the mechanisms involved in angiogenesis. Particular attention will be paid to the growth factors and receptors that are known to mediate angiogenesis, and a description of some of the cell signaling mechanisms that are involved in the regulation of angiogenesis will be described. Finally, potential targets that may provide opportunities to enhance or block angiogenesis will be discussed.