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

Abstract

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.

Correction of haemorrhagic shock-associated coagulopathy and impaired haemostasis by plasma, prothrombin complex concentrates or an activated protein C-targeted DNA aptamer in mice

“…This finding is perhaps unsurprising given that the PT uses high concentrations of tissue factor that promote clotting within 10-14 s and has little or no capacity to assess clot lysis 35 . Like other investigators using rodent models of ATC/TIC [36][37][38] , we observed a substantial elevation in plasma aPC activity after trauma and haemorrhagic shock. Saline-treated mice exhibited the greatest increase in aPC levels of groups surveyed, an 8.5-fold elevation indicative of an active process, given its magnitude and opposite direction from any dilutional effects.…”

“…It is pragmatically focused on our primary research question of which resuscitation fluids restored haemostatic control and ameliorated coagulopathy, and which did not. Others have also modified the original Chesebro et al model to include full anaesthetic coverage in mice and rats 37,38,41 .…”

“…Further investigations of aPC inhibition via HS02-52G are also warranted to determine optimal doses and if prophylactic administration is effective. Prophylactic administration of a variant form of recombinant FVa resistant to aPC inactivation ( Super FVa) has been reported to reduce blood losses significantly in mice subjected to extensive hepatectomy leading to uncontrolled haemorrhage 38 .…”

The Vascular Endothelium and Coagulation: Homeostasis, Disease, and Treatment, with a Focus on the Von Willebrand Factor and Factors VIII and V

“…The resistance of SUPER FVa to APC’s anticoagulant effect means that therapeutic strategies based on this recombinant factor are likely to alter the homeostasis process, allowing a longer-term maintenance of FV plasma levels. SUPER FVa’s resistance against inactivation by APC is also an asset in cases of acute traumatic coagulopathy (ATC), characterized by increased levels of APC and hyperfibrinolysis [ 321 ].…”

Selective modulation of activated protein C activities by a nonactive site–targeting nanobody library

“…Hemophilia patients with the APC resistant FV Leiden variant were observed to have reduced bleeding (4)(5)(6). Mice with acute traumatic coagulopathy experienced significantly less bleeding when treated with an APCresistant super FVa variant (7). These findings show that APC inhibition promotes a pro-coagulant state.…”