Plasminogen Activator Inhibitor-1 (PAI-1) is a serine protease inhibitor and the primary physiological inhibitor of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA). It plays a crucial role in regulating fibrinolysis, the process of fibrin clot degradation. Elevated PAI-1 levels are associated with various pathological conditions, including thrombotic disorders, cardiovascular disease, metabolic syndrome, and certain cancers, due to its prothrombotic and antifibrinolytic effects.