The role of vascular endothelial cells in the regulation of fibrinolysis.

Vascular endothelial cells play an important role in the regulation of fibrinolysis. They synthesize and secrete tissue-type plasminogen activators (t-PA), urinary-type plasminogen activators (u-PA), as well as plasminogen activator inhibitor type 1 (PAI-1). Synthesis of t-PA, u-PA, and PAI-1 are regulated by a variety of external agonists. The fibrinolytic capacity of endothelial cells derived from macrovascular and microvascular origin is regulated differently. Furthermore, endothelial cells bind plasminogen, plasminogen activators and plasminogen activator inhibitors. Depending on their state of activation endothelial cells may promote or inhibit fibrinolysis.