Development of a Nonhuman Primate (Rhesus Macaque) Model of Uncontrolled Traumatic Liver Hemorrhage.

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Hemorrhage is the leading cause of potentially survivable trauma mortality, necessitating the development of improved therapeutic interventions. The objective of this study was to develop and characterize a reproducible clinically translatable nonhuman primate model of uncontrolled severe hemorrhage. Such a model is required to facilitate the development and meaningful evaluation of human-derived therapeutics. In Rhesus macaques, a laparoscopic left-lobe hepatectomy of 25% (n = 2), 50% (n = 4), or 60% (n = 6) was performed at T = 0 min, with no attempt at hemorrhage control until T = 120 min. A constant-rate infusion of normal saline was administered between T = 15 and 120 min to a total volume of 20 mL/kg. At T = 120 min, a laparotomy was performed to gain surgical hemostasis and quantify blood loss. Physiological parameters were recorded, and blood samples were collected at defined intervals until termination of the study at T = 480 min. Statistical analyses used Student t tests, with P < 0.05 considered statistically significant. Results are reported as mean ± SEM. The calculated percent blood loss for the 25% hepatectomy group was negligible (2.3% ± 0.2%), whereas the 50% and 60% hepatectomy groups exhibited 26.6% ± 7.1% and 24.9% ± 3.8% blood loss, respectively. At T = 5 min, blood pressure for the 25%, 50%, and 60% hepatectomy groups was reduced by 13.8%, 60.8%, and 63.2% from the respective baseline values (P < 0.05). In the 60% hepatectomy group, alterations in thromboelastometry parameters and systemic inflammatory markers were observed. The development of a translatable nonhuman primate model of uncontrolled hemorrhage is an ongoing process. This study demonstrates that 60% hepatectomy offers a significant reproducible injury applicable for the evaluation of human-derived therapeutics.