Vascular endothelium--role in chronic inflammatory disease.

The vascular endothelial lining of blood vessels plays a key 'target-effector' role in vivo, integrating the body's response to inflammatory cytokines, chemokines and growth factors (derived from both endothelial cells themselves and from other cells such as leukocytes and fibroblasts), to allow leukocyte activation, adhesion and extravasation from the flowing blood into underlying tissue. Endothelial proliferation, through the process of angiogenesis, results in an increased cell surface area for these events to occur, and further functions to deliver oxygen and nutrients, and to remove waste products. In addition to playing an important role in physiology, the endothelium is thus an active participant in inflammatory pathologies. One of the best understood diseases in which inflammation and angiogenesis play a part is rheumatoid arthritis (RA). Blockade of the inflammatory cascade in RA has significant consequences for the vasculature, highlighting the links between reducing endothelial activation and therapeutic benefit in chronic inflammatory disorders.