The adhesive properties of the endothelium, the single-cellthick lining of the cardiovascular system, are central to its biology and pathobiology. In health, the luminal endothelial surface provides a relatively nonadhesive, nonthrombogenic container for the cellular and macromolecular constituents of the blood. Specialized adhesive molecules localized at the lateral cell–cell junctions control transendothelial permeability and the movement of leukocytes from the blood into the tissue spaces of the body. Along its basal aspect, focal adhesion complexes, consisting of transmembrane integrins and associated intracellular proteins, physically link the extracellular matrix to cytoskeletal elements, providing both stability and plasticity to the vascular lining. In disease, these various adhesive interactions can undergo dramatic changes. As is highlighted by the articles in this Perspectives Series, the molecular biological analysis of endothelial adhesion pathobiology has led to the discovery of novel families of molecules (eg, the selectins), as well as a more dynamic appreciation of their mutual interactions (eg, the leukocyte–endothelial adhesion cascade). This knowledge has added much to our basic understanding of vascular biology, as well as the pathophysiology of clinically important processes, such as acute and chronic inflammation, atherosclerosis, angiogenesis, vascular injury and repair, and developmental malformations. In certain instances, these insights have provided the basis for the rational design of promising new therapeutics for cardiovascular disease.

A central premise of modern vascular biology is that the endothelial lining is a dynamically mutable interface, locally responsive to various stimuli originating from the circulating blood and/or neighboring cells and tissues, and thus can actively participate in the physiological adaptation or pathophysiological dysfunction of a given region of the vasculature (1). From a teleological standpoint, the endothelium appears ideally suited to function in this capacity, given its unique anatomical position between blood and tissues, and its ability to generate an impressive repertoire of biological effectors,(eg,