Vessel wall interactions regulating thrombosis.

Endothelial cells are responsible for the secretion or surface expression of a wide variety of mediators involved in the control of thrombosis. These include von Willebrand factor, prostacyclin, nitric oxide, thrombomodulin, tissue-type plasminogen activator and its inhibitor, tissue factor and the tissue factor pathway inhibitor. The production of each of these can be modulated; in some cases very rapidly in response to external stimuli, in other cases more slowly. Thrombin is a key stimulus, which affects the production of almost all of these mediators. In addition, several cytokines and bacterial endotoxins shift the balance of endothelial mediator secretion from the basal anticoagulant profile towards a procoagulant profile.