Treatment with fibrinogen γ-chain peptide-coated, adenosine 5′-diphosphate-encapsulated liposomes as an infusible hemostatic agent against active liver bleeding in rabbits with acute thrombocytopenia

Background: We evaluated the hemostatic efficacy of H12-(adenosine 5′-diphosphate [ADP])-liposomes in the setting of active liver bleeding in rabbits with dilutional thrombocytopenia after massive transfusion. Study Design and Methods: Acute thrombocytopenia (platelet [PLT] count < 50 × 10⁹/L) was induced in rabbits by repeated blood withdrawal and isovolemic transfusion of autologous washed red blood cells. Liver hemorrhage was initiated by a penetrating liver injury. Subsequently, the animals received tamponade treatment for the liver hemorrhage for 5 minutes and were intravenously administered H12-(ADP)-liposomes with PLT-poor plasma (PPP), PLT-rich plasma (PRP), PPP alone, H12-(phosphate-buffered saline [PBS])-liposome/PPP, or H12-(ADP)-liposomes/PPP plus fibrinogen concentrate during the tamponade. Results: Administration of H12-(ADP)-liposomes/PPP rescued 60% of the rabbits from the liver hemorrhage; PRP administration rescued 50%. In contrast, rabbits receiving PPP or H12-(PBS)-liposome/PPP achieved only 10 or 17% survival, respectively, for the first 24 hours. H12-(ADP)-liposomes/PPP as well as PRP consistently reduced bleeding volumes and shortened clotting times (CTs) in comparison to PPP administration. Specifically, bleeding volumes in the initial 5 minutes averaged 11 mL (H12-(ADP)-liposomes/PPP) and 17 mL (PRP) versus 30 mL (PPP; p < 0.05); CTs averaged 270 and 306 seconds versus 401 seconds (p < 0.05). H12-(ADP)-liposomes were observed at the bleeding site with thrombus formation, suggesting an induction of thrombi. Neither macro- nor microthrombi were detected in the lung, kidney, spleen, or liver in rabbits treated with H12-(ADP)-liposomes. Supplementation of fibrinogen to H12-(ADP)-liposomes/PPP did not significantly improve rabbit survival. Conclusions: H12-(ADP)-liposomes might be a safe and effective therapeutic tool during damage control surgery for trauma patients with acute thrombocytopenia and massive bleeding.