Vascular biology

Vascular biology is the study of the physiology of the vasculature and how it may be the target for disease processes. An understanding of vascular biology is central to the study of rheumatic disease for three reasons: it is an integral part of a functioning immune system; it is the primary site of pathology in many conditions; and it is the site of the important secondary complications of chronic inflammation, endothelial dysfunction and atherosclerosis. Vascular biology requires a detailed knowledge of the anatomy and physiology of the vasculature and its constituent vessels. The multistep process by which leucocytes interact with endothelium lining postcapillary venules in order to leave the circulation and migrate towards a site of inflammation is central to the pathology of inflammatory disease. The vasculature is the primary site of injury in several rheumatic diseases, including the vasculitides. It may also be damaged by chronic inflammation, leading to endothelial dysfunction and accelerated atherosclerosis. Thrombosis is also a critical pathological process in several chronic inflammatory diseases, particularly the anti-phospholipid antibody syndrome and Behçet's syndrome. The vascular endothelium is central to angiogenesis, the process of new capillary outgrowth, upon which synovial proliferation in inflammatory arthritis is dependent. Angiogenesis is inhibited by current anti-rheumatic therapies and may become a target for novel anti-rheumatic drugs. An increasing area of research concerns the direct effects of drugs used in the treatment of atherosclerosis and inflammatory disease on the endothelium, and whether these agents are beneficial or harmful. Of particular interest to rheumatologists are the vascular effects of statins, disease-modifying anti-rheumatic drugs (DMARDs), immunosuppressants, and cyclooxygenase inhibitors.