The Action of Heparin and Other Polysaccharides on the Rigidity of Surface Layers of Fibrinogen

Abstract

Our earlier findings(Thromb. Res. 1:5,1972), that surface layers (SL) of heparin plasma showed decreased rigidity or torque values (J) when compared to SL of oxalate plasma from the same blood withdrawal, led to studies of effect of different’ commercial preparations of heparin (H) and other polysaccharides on SL of 0.4% fibrinogen (Fg) solutions. Depolymerized hyaluronate, chondroitin sulfate and dextran sulfate markedly decreased (J) of FgSL. 1% H lowered J more than 0.1% H. These findings were not consistent with all H preparations, some of which did not lower J. The anticoagulant activity (AA) of H, thus, does not correspond to this J reducing action of certain Hs on FgSL. This will be discussed in connection with studies of H uptake on the endothelium by Hiebert and Jaques who concluded that H may act as antithrombotic agent independently from its AA. (Artery 2:26, 1976). Our findings with H suggest that in thrombosis therapy any commercial H may not necessarily be useful, if merely its AA is taken into consideration, particularly since the initiation of thrombosis according to Copley’s concept is due to the clotting of Fg without thrombin interaction. Since we view FgSL formation on the endothelium to progress to a surface gel state with consequent large increase in volume, the polysaccharides and H preparations, found to reduce J, may have both surface gelation inhibiting (SL antigeloplastic) and antithrombotic actions. (Aided in part by NIH grant HL19013-02.)