[Therapeutic evaluation of recombinant thrombomodulin]

Thrombomodulin (TM) is an endothelium-associated glycoprotein that converts thrombin from a procoagulant protease to an anticoagulant. Thrombin, a key enzyme in thrombus formation, binds to TM molecules on endothelium with very high affinity. After binding to TM, thrombin fails to act on the coagulation factors and platelets, and its ability to activate protein C is enhanced more than 1000-fold. We expressed soluble recombinant TM (rTM) in CHO cells and evaluated its antithrombotic effect on thrombin-induced thromboembolism in mice and lipopolysaccharide (LPS) induced disseminated intravascular coagulation (DIC) in rats. Thrombin injection into mouse caused acute thromboembolism resulting instantaneous death, however preinjection of rTM neutralized the lethal effect of thrombin in a dose-dependent manner. Soluble rTM also improved the consumption of fibrinogen and platelets in experimental DIC-rats induced by LPS. The effect of rTM was confirmed in histologically. These data suggest that rTM may have a therapeutic effect on thrombosis or DIC in human.