Anticoagulant activity of artificial biomedical materials with co-immobilized antithrombin III and heparin

An approach to providing anticoagulant activity to biomedical materials was presented, applying an immobilization technique. Antithrombin III (AT III) inactivates the activated coagulation factors including Factor Xa and thrombin. Heparin stimulates the inactivation of Factor Xa and thrombin by AT III. Thus AT III and heparin were co-immobilized on Sepharose 4B, polyvinyl alcohol, polyhydroxy-ethyl methacrylate and silicone-coated nylon by the cyanogen bromide procedure. Those co-immobilized preparations, abbreviated as I-AT III . Hep, actively neutralized both Factor Xa and thrombin. The activity of I-AT III . Hep was much higher than immobilized heparin and/or immobilized AT III. I-AT III . Hep, like soluble AT III and heparin, instantaneously neutralized both thrombin and Factor Xa. When two enzymes, thrombin and Factor Xa, were present, I-AT III . Hep neutralized Factor Xa in preference to thrombin : The neutralization of thrombin was inhibited by the presence of Factor Xa, but neutralization of Factor Xa was independent of the presence of thrombin. The amount of Factor Xa neutralized was higher than that of thrombin.