Fibrinolyyttisyyttä

Fibrinolyyttisyyttä refers to the process of fibrinolysis, which is the breakdown of fibrin, a protein that forms the meshwork of blood clots. This physiological process is crucial for maintaining vascular patency and preventing the excessive accumulation of thrombi throughout the circulatory system. Fibrinolysis is primarily mediated by a complex enzymatic system involving plasmin, a serine protease.

The activation of fibrinolysis begins with the release of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) from endothelial cells. These activators convert plasminogen, an inactive precursor circulating in the blood, into plasmin. Plasmin then binds to fibrin and degrades the cross-linked fibrin polymer, effectively dissolving the clot.

The fibrinolytic system is tightly regulated by various endogenous inhibitors, such as plasminogen activator inhibitor-1 (PAI-1) and alpha-2-antiplasmin. These inhibitors prevent premature or excessive fibrinolysis, which could lead to bleeding. Disruptions in this delicate balance, either due to overactivation of fibrinolysis or insufficient inhibition, can result in hemorrhagic disorders. Conversely, impaired fibrinolysis can contribute to thrombotic conditions, as clots are not effectively removed. Therapeutic agents that enhance fibrinolysis, known as thrombolytics, are used clinically to treat conditions like myocardial infarction and stroke by dissolving existing blood clots.