Cytochrome P450 2E1 Predicts Liver Retrieval from Donation After Circulatory Death Using Air-Ventilated Normothermic Machine Perfusion

The optimal oxygen concentration is unclear for normothermic machine perfusion (NMP) of livers from donation after circulatory death donors (DCD). Our purposes were to investigate the effect of air-ventilated NMP on liver retrieval from DCD rats, and to analyze the underlying mechanism. Normothermic liver perfusion was performed using the NMP system with either air ventilation or oxygen ventilation for 2h in the rat liver following warm ischemia and cold ischemia preservation. Proteomics and metabolomics were used to reveal the significant molecular networks. The bioinformation analysis was validated by administering peroxisome proliferator activator receptor-γ (PPARγ) antagonist and agonist via ex vivo perfusion circuit in the air-ventilated NMP. Results showed that air-ventilated NMP conferred a better functional retrieval and a less inflammatory response in the rat DCD liver; integrated proteomics and metabolomics analysis indicated that intrahepatic docosapentaenoic acid (DPA) downregulation and upregulation of cytochrome P450 2E1 (CYP2E1) expression and activity were associated with DCD liver retrieval with air-ventilated NMP; PPARγ antagonist worsened liver function under air-oxygenated NMP whereas PPARγ agonist played the opposite role. In conclusion, air-ventilated NMP confers a better liver retrieval from DCD rats through the DAP-PPARγ-CYP2E1 axis; CYP2E1 activity provides a biomarker of liver retrieval from DCD.