PROTEIN-C, AN ANTITHROMBOTIC PROTEIN, IS REDUCED IN HOSPITALIZED-PATIENTS WITH INTRAVASCULAR COAGULATION

Abstract

Activated protein C is a potent anticoagulant and profibrinolytic enzyme that can be derived from the vitamin-K-dependent serine protease zymogen, protein C, by the action of thrombin. Protein C antigen concentration was determined in plasmas from normals (40) and from 38 patients with intravascular coagulation as evidenced by positive FDP [fibrin degradation products] (< 10 .mu.g/ml). Plasma protein C was 4 .mu.g/ml in normals and was significantly depressed (< 2 SD below the mean of normals) in 19 of the 38 patients. Of 15 patients with suspected intravascular coagulation but normal FDP, protein C was decreased in 5 individuals; 3 of these 5 patients had liver disease. Extensive activation of the coagulation system in vivo apparently causes a significant consumption of protein C, presumably due to its activation by thrombin and subsequent clearance.