Alterations of cytochrome P450-mediated drug metabolism during liver repair and regeneration after acetaminophen-induced liver injury in mice.

Acetaminophen (APAP)-induced liver injury (AILI) is the leading cause of acute liver failure in the United States, but its impact on metabolism, therapeutic efficacy, and adverse drug reactions (ADRs) of co- and/or subsequent administered drugs are not fully investigated. The current work explored this field with a focus on the AILI-mediated alterations of cytochrome P450 (CYP)-mediated drug metabolism. Various levels of liver injury were induced in mice by treatment with APAP at 0, 200, 400, and 600 mg/kg. Severity of liver damage was determined at 24, 48, 72, and 96 hours by plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), microRNA miR122, and tissue staining. The expression and activities of CYP3A11, 1A2, 2B10, 2C29, and 2E1 were measured. Sedation efficacy and ADRs of midazolam, a CYP3A substrate, were monitored after APAP treatment. ALT, AST, and miR122 increased at 24 hours after APAP treatment with all APAP doses, while only 200 and 400 mg/kg treated groups recovered back to normal levels at 72 and 96 hours. The expression and activity of the CYPs significantly decreased at 24 hours with all APAP doses, but only recovered back to normal at 72 and 96 hours with 200 and 400, but not 600 mg/kg of APAP. The alterations of CYP activities resulted in altered sedation efficacy and ADRs of midazolam, which were corrected by dose justification of midazolam. Overall, this work illustrated a low-CYP expression window after AILI, which can decrease drug metabolism and negatively impact drug efficacy and ADRs. Significance Statement The data generated in the mouse model demonstrated that expression and activities of CYP enzymes and correlated drug efficacy and ADRs are altered during the time course of liver repair and regeneration after liver is injured by treatment with APAP. Dose justifications based on predicted changes of CYP activities can achieve desired therapeutic efficacy and avoid ADRs. The generated data provide fundamental knowledge for translational research to drug treatment for patients during liver recovery and regeneration who have experienced AILI.