An engineered activated factor V for the prevention and treatment of acute traumatic coagulopathy and bleeding in mice.

Acute traumatic coagulopathy (ATC) occurs in ≈30% of trauma patients and is associated with increased mortality. Excessive generation of activated protein C (APC) and hyperfibrinolysis are believed to be driving forces for ATC. Two mouse models were used to investigate whether an engineered activated FV variant (superFVa) that is resistant to inactivation by APC and contains a stabilizing A2-A3 domain disulfide bond, is able to reduce traumatic bleeding and normalize hemostasis parameters in ATC. First, ATC was induced by the combination of trauma and shock. ATC was characterized by APTT prolongation and reductions of FV, FVIII, and fibrinogen, but not FII and FX. Administration of superFVa normalized the APTT, returned FV and FVIII clotting activity levels to their normal range, and reduced APC and thrombin-antithrombin (TAT) levels, indicating improved hemostasis. Next, a liver laceration model was used where ATC develops as the consequence of severe bleeding. SuperFVa prophylaxis prior to liver laceration reduced bleeding, prevented APTT prolongation, depletion of FV and FVIII, and excessive generation of APC. Thus, prophylactic administration of superFVa prevented the development of ATC. SuperFVa intervention started after the development of ATC stabilized bleeding, reversed the prolonged APTT, returned FV and FVIII levels to their normal range, and reduced TAT levels that were increased by ATC. In summary, superFVa prevented ATC and traumatic bleeding when administered prophylactically, and superFVa stabilized bleeding and reversed abnormal hemostasis parameters when administered while ATC was in progress. Thus, superFVa may be an attractive strategy to intercept ATC and mitigate traumatic bleeding.