[Structure, function and use of fibrinolysis-promoting and inhibiting factors]

Our knowledge about the components of the fibrinolytic system has greatly increased during the last few years thanks to the cloning of the cDNA of the two plasminogen activators t-PA and u-PA, of the two plasminogen activator inhibitors PAI-1 and 2, and of other profibrinolytic and of inhibitory factors of this system. The two principal plasminogen activators (PA) and the two PA-inhibitors are present in infinitesimal concentrations in blood (pM to microM range) and in tissues. The expression of the t-PA and of the u-PA cDNA in mammalian cells and in E. coli bacteria has rendered it possible to produce sufficient amounts of these thrombolytic disorders for clinical studies. Over 2000 patients afflicted with acute myocardial infarction have been treated so far with recombinant t-PA. In general, the thrombolytic effect of t-PA appears to be superior to that obtained with streptokinase and the fibrin-specific-PA produces lesser fibrinogenolysis than the first generation thrombolytic agents streptokinase and two-chain urokinase.