Fibrinolytic action of a new semi-synthetic polysaccharide sulfate, galactan polysulfate (DH 6322), in the rat.

Galactan polysulfate, DH 6322, when added to rat plasma, shortened euglobulin clot lysis time through both increase in the recovery of plasminogen activator activity in euglobulin precipitates and direct acceleration of fibrinolysis. DH 6322 treatment also resulted in accelerating plasma clot lysis induced by urokinase. The effect of DH 6322 was further studied with a purified system composed of bovine fibrinogen and plasminogen. In this system, DH 6322 was found to be a potent stimulator of both fibrinolysis and fibrinogenolysis induced by urokinase. The activation process of plasminogen was not affected by DH 6322 even in the presence of fibrin or fibrinogen. The accelerating effect of DH 6322 on fibrinolysis in the purified system was scarcely affected by addition of plasma antifibrinolytic factors. DH 6322 also stimulated fibrin clot lysis induced by a low concentration of purified plasmin in place of plasminogen and urokinase, and its accelerating effect was not observed in the presence of tranexamic acid. Formation of fibrin clot susceptible to generated plasmin was observed at relatively high concentrations of DH 6322 above 80 micrograms/ml. Additional experiments indicated that DH 6322 increased the amount of plasminogen bound to fibrin. These results suggested that DH 6322 stimulated fibrinolysis through increasing the binding of plasminogen or plasmin to fibrin.