The antithrombotic effect of a novel hirudin derivative after reconstruction of carotid artery in rabbits

IntroductionHirudin is a direct thrombin inhibitor that has potential mechanistic advantages over indirect inhibitors. Peptides containing the RGD motif competitively inhibit binding of fibrinogen to glycoprotein IIb/IIIa on platelets, thus inhibiting platelet aggregation. A novel hirudin derivative, recombinant RGD-hirudin (r-RGD-hirudin), was engineered by fusing the tripeptide RGD sequence to the native hirudin. We tested the antithrombotic effect of r-RGD-hirudin using a carotid artery reconstruction model in rabbits.Materials and methodsA fusion gene encoding r-RGD-hirudin was constructed and expressed at high levels in Pichia pastoris. Following traumatic injury and anastomosis, 42 New Zealand White rabbits were randomized to receive normal saline, abciximab, wild-type hirudin, or r-RGD-hirudin. Fibrinogen concentration, aPTT, TT, PT, and PAGm were measured prior to and following the operation. Carotid angiography and pathological examination of the anastomotic site were performed to compare patency rates among the groups.ResultsThe r-RGD-hirudin significantly prolonged aPTT, TT, PT and inhibited PAGm following carotid anastomosis in rabbits. The median dose of r-RGD-hirudin (0.5 mg/kg) had a therapeutic effect equal to that of wild-type hirudin (1.0 mg/kg) and higher than that of abciximab (0.2 mg/kg) with regard to patency rates.ConclusionsCompared to wild-type hirudin or antiplatelet agent, the novel anticoagulant, r-RGD-hirudin was capable of inhibiting both thrombin activity and platelet aggregation, and was demonstrated to be effective in the prevention of thrombosis.