The endothelium is an organ in its own right, which weighs more than 1.5 kg and has the surface of 4 tennis courts or one football field. The endothelium is a single layer of cells which forms the interface between blood and the surrounding tissues. It is the target of many hormones and produces very active compounds such as endothelin.
Normal endothelium protects the vessel from adhesion of cells.
The significance of the endothelium as an active organ was only recently realized, and these findings were rewarded with the 1998 Nobel Prize of Medicine to Robert Furchgott, Louis Ignarro and Ferid Murad. The pathology of the endothelium is linked to a wide variety of health disorders, and drugs aiming at specific targets related to the endothelium may therefore have a therapeutic potential in the cardiovascular field as well as in inflammation, metabolic diseases and cancer. Normal endothelium protects the vessel from adhesion of cells. A dysfunctional endothelium cannot prevent adhesion of platelets and fibrin strands.