Plazminogénaktivátorok

Plazminogénaktivátorok, often abbreviated as PA, are a group of enzymes that play a crucial role in the body's fibrinolytic system. Their primary function is to convert plasminogen into plasmin. Plasmin is a serine protease that is responsible for breaking down fibrin, the main protein component of blood clots. This process, known as fibrinolysis, is essential for dissolving unnecessary or harmful blood clots, thereby maintaining blood flow and preventing complications.

There are two main types of endogenous plasminogen activators: tissue plasminogen activator (t-PA) and urokinase plasminogen activator (u-PA). Tissue-type plasminogen activator (t-PA) is found in endothelial cells and is released into the bloodstream. It is highly specific for fibrin-bound plasminogen, meaning it primarily activates plasminogen that is already associated with a blood clot. Urokinase plasminogen activator (u-PA) is produced by various cells, including kidney cells and macrophages, and is involved in both fibrinolysis and other processes such as tissue remodeling and cell migration.

Exogenous plasminogen activators are also used therapeutically. These are synthetic or recombinant versions of PA that are administered to patients to dissolve blood clots in conditions like myocardial infarction (heart attack), stroke, and deep vein thrombosis. Common examples of therapeutic PAs include alteplase (a recombinant t-PA) and streptokinase (a bacterial protein that activates plasminogen). The use of these agents is carefully managed due to the risk of bleeding complications.