TAFI

TAFI most commonly refers to thrombin-activatable fibrinolysis inhibitor, a regulator of blood clot dissolution. It is a plasma proenzyme that circulates as procarboxypeptidase U and is produced mainly by the liver.

TAFI is activated by thrombin in the presence of thrombomodulin, producing the active enzyme TAFIa, a metallocarboxypeptidase. TAFIa removes C-terminal lysine residues from partially degraded fibrin, which reduces the binding of plasminogen and tissue plasminogen activator to fibrin. This slows fibrinolysis and promotes clot stability. Activation can also occur, to a lesser extent, via plasmin. TAFI activity is relatively short-lived and can be influenced by inflammatory and metabolic states.

In clinical contexts, alterations in TAFI levels or activity have been studied for associations with thrombotic and bleeding disorders. Elevated TAFI activity is linked with reduced fibrinolysis and may contribute to thrombotic risk, while low activity can be associated with bleeding tendencies. Levels can be affected by genetic variation, liver function, pregnancy, and inflammatory status. Measurements typically assess either TAFI antigen levels or functional activity.

TAFI is an acronym that can have other meanings in different disciplines depending on context. This article focuses on the biomedical meaning most widely used in medical literature.