Participation of protein Z-dependent protease inhibitor and protein Z system in the pathomechanism of thrombotic complications.

Thrombotic complications of unknown etiology remain a serious diagnostic and therapeutic problem. Occurrence of the inherited polymorphisms of genes encoding proteins involved in the coagulation cascade is one of the possible causes of these complications. In recent years, protein Z (PZ) and PZ-dependent protease inhibitor (ZPI) have been added to the list of prothrombotic factors. PZ is a glycoprotein serving as a cofactor of ZPI, which is responsible for the inhibition of prothrombinase. Expression of the PZ gene is under the control of many transcriptional factors; several polymorphisms alternate the rate of gene expression. The present article describes the significance of the ZPI-PZ system in venous and arterial thrombosis, adverse pregnancy outcomes and antiphospholipid syndrome complications.