On the interaction of heparin-containing polymers with plasma proteins and blood

In vitro exper iments showed that polymeric hydrogels containing covalently immobilized heparin affect the parameters of blood clotting system. This is not accounted for by the elution of heparin into the surrounding medium and this property of heparin-containing polymers is caused by specific interaction of immobilized heparin with plasma proteins. By the methods of coagulograms and thromboelastography it was revealed that the decrease of total blood anticoagulant activity takes place due to the decrease in blood of fibrinogen, prothrombin and thrombin content and the suppression of fibrin stabilizing factor activity. Free heparin content in blood was left unaffected. It was found that plasma proteins permeate the hydrophilic polymer matrix and interact with immobilized heparin. Binding strength for immobilized heparin is decreased in the array fibrinogen congruent to thrombin much greater than plasmin greater than serum albumin. Complexes of immobilized heparin with fibrinogen, thrombin and plasmin display lytic action towards unstabilized fibrin.