Coagulation factor XIIIa (FXIIIa)

Factor XIIIa, also known as fibrinoligase, is the activated form of the proenzyme Factor XIII, a transglutaminase that plays a critical role in the final stage of the blood coagulation cascade [1, 4]. It is responsible for the covalent cross-linking of fibrin monomers, which stabilizes the blood clot and increases its resistance to mechanical stress and enzymatic degradation by plasmin [1, 12]. Beyond hemostasis, Factor XIIIa is involved in diverse biological processes including wound healing, angiogenesis, and tissue repair [2, 7]. It is a well-established therapeutic target for replacement therapy in patients with congenital or acquired Factor XIII deficiency [17]. Additionally, Factor XIIIa is an emerging target for novel anticoagulants; by inhibiting its cross-linking activity, drugs can produce more fragile clots that are more susceptible to fibrinolysis, potentially offering a safer antithrombotic approach with a lower risk of spontaneous bleeding compared to traditional anticoagulants [1, 21].

Other names

FibrinoligasePlasma transglutaminaseLaki-Lorand factor (activated)Activated coagulation factor XIIIF13A1 (activated)

Factor XIIIa inhibitors block the transglutaminase activity of the enzyme, preventing the covalent cross-linking of fibrin chains and the incorporation of alpha-2-antiplasmin into the clot, which results in the formation of mechanically weaker clots that are more susceptible to fibrinolysis. Conversely, Factor XIII replacement therapy restores this cross-linking activity to treat deficiency-related bleeding.