[The vascular endothelium--a multifunctional organ]

The authors summarize the role of the vascular endothelium in hemostasis, thrombosis, vasomotor regulation, inflammation and angiogenesis. Quiescent endothelium is antithrombogenic, whereas perturbed endothelial cells become thrombogenic. The endothelium produces both vasodilating substances like endothelial derived relaxing factor and prostacyclin and vasoconstrictive compounds such as the endothelins. The presence of leucocyte adhesion molecules on the endothelial surface allows specific interactions with circulating leucocytes. Surface expression of HLA-antigens class I and II further underscores the importance of the endothelial cells in the inflammatory process. In the recent years it has become evident that the endothelial cells play a major role in the pathogenesis of diseases such as atherosclerosis, preeclampsia, hemolytic uremic syndrome and certain vasculitides.