SERPINE1 and acute respiratory distress syndrome: Plasminogen activator inhibitor-1 (PAI-1) is an essential biomarker in the fibrinolysis/coagulation pathway linked to ARDS, being a serine protease inhibitor whose role is to control fibrinolysis by inhibiting tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) [74].