Fig. 1

Fibrin clot formation and lysis. Following vascular injury, tissue factor (TF) is released followed by a complex interaction between the cellular and protein arms of coagulation, resulting in activation of various coagulation factors, including FV, FVII, FIX and FX, culminating in the formation of thrombin, which converts soluble fibrinogen into a network of insoluble fibrin fibres. Thrombin also activates factor XIII (FXIII) to active FXIII (FXIIIa), which crosslinks the fibrin fibres and also incorporates antifibrinolytic proteins into the clot. Plasmin, derived from plasminogen by the action of tissue plasminogen activator (tPA), is the enzyme responsible for fibrin clot lysis, resulting in the generation of fibrin degradation products. The main inhibitors of fibrinolysis are plasmin inhibitor (PI) and plasminogen activator inhibitor (PAI-1)