Modeling Warfarin Associated Intracerebral Hemorrhage (ICH) in Cynomolgus Monkeys

Intracerebral hemorrhage (ICH) accounts for about 15% of strokes and leads to higher mortality. However, its underlying pathophysiologic mechanism remains gloomy, partially due to the lack of suitable animal models in research. Approximately 20% ICH cases are associated with the use of oral anticoagulants, warfarin for the most instances in clinic, especially following the long-term treatment. Even though the coumarin drugs has been used in rodents for comparison of standard-of-care effects in ICH studies, the elucidation of results must bear the significant differences of gyrencephalic brain structure, brain vasculature and various biological interactions affecting the hemorrhage and hemostasis between rodents and human being. Quite a few works have been reported in study of strokes, particularly, the cerebral ischemic stroke in cynomolgus monkeys (Macaca fascicularis) for its high homology to human. In order to establish a more clinical relevant model for ICH and saver anticoagulant research, we studied ICH in cynomolgus monkeys by injection of collagenase in brain and characterized the effect of warfarin treatment by MRI measurement. Following injection of type IV collagenase into internal capsule, distinct acute, sub-acute, and chronic phases of ICH were observed, with the highest level of cerebral hematoma volume at 3 days after ICH induction measured by a GE signa excite 1.5T MRI scanner. Pretreatment with 0.3 mg/kg of warfarin daily for 6 days significantly increased the hematoma volumes to proximal 10% of cerebral hemisphere compared to the 4% with saline treatment. In addition, the AUC of hematoma volume changes was also remarkably enlarged with the warfarin treatment as measured at different time points following ICH. Transfusion of 30 ml of autologous fresh frozen plasma (FFP) and injection of 1 mg Vitamin K reduced the effects of warfarin treatment in hematoma and AUC enlargement, and ameliorated ICH stroke associated symptoms. The results of coagulation tests were all in agreement with the warfarin associated effects on cerebral hematoma in cynomolgus monkeys. Our data demonstrated the successful establishment of ICH model in cynomolgus monkeys and the clinical relevant treatments, such as warfarin and FFP, can be incorporated as the controls for proper researches in ICH and its therapeutics. With the high similarity in brain and high cross reactivity in target to human, the cynomolugs monkey ICH model adds a valuable tool to evaluate new therapeutic approaches and the safety of novel anticoagulants, especially for the human target-specific interventions, such as plasma products, biologics, oligonucleotides, and peptides.