Histidine-Rich Glycoprotein Modulates the Anticoagulant Activity of Heparin in Human Plasma

Publisher Website
Google Scholar
Abstract
Addition of 0.05 IU of heparin per ml normal plasma prolongs its thrombin time from 20 to 27s, but that of plasma specifically depleted in histidine-rich glycoprotein (by immunoadsorption) from 20 to 180s. Reconstitution of the depleted plasma with normal plasma or with purified histidine-rich glycoprotein normalizes its thrombin time. In 54 plasma samples from hospitalized patients a significant negative correlation was found between the anticoagulant activity of heparin measured by thrombin inhibition and the plasma level of histidine-rich glycoprotein (r = 0.69). It is concluded that the level of histidine-rich glycoprotein modulates the anticoagulant activity of heparin in human plasma to an extent which appears to be pharmacologically and possibly clinically relevant.