indirect fibrinolysis; protein C pathway

• Protein C pathway


  1. Thrombomodulin binds to thrombin

  2. Thrombomodulin-bound thrombin activates protein C

  3. Activated protein C degrades factors Va and VIIIa
• Thrombomodulin


  Membrane protein expressed on endothelial cells that binds to thrombin
• Activated protein C


  Cleaves and inactivates factors Va and VIIIa, preventing further thrombin and fibrin formation
• Thrombomodulin-bound thrombin


  Has the opposite function of free thrombin - it inhibits rather than promotes clot formation
• The protein C pathway regulates coagulation by preventing further thrombin and fibrin formation in areas without vascular injury
• This is an indirect form of fibrinolysis, as it prevents fibrin formation rather than directly degrading existing fibrin clots
• The protein C pathway, along with direct fibrinolysis, work together to prevent uncontrolled fibrin formation and degrade clots when no longer needed