Murine Cyp3a knockout chimeric mice with humanized liver: prediction of the metabolic profile of nefazodone in humans.
Biopharm Drug Dispos. 2015 Sep 9;
Authors: Nakada N, Kawamura A, Kamimura H, Sato K, Kazuki Y, Kakuni M, Ohbuchi M, Kato K, Tateno C, Oshimura M, Usui T
Chimeric mice with humanized livers (PXB mice) are used to investigate the metabolism and pharmacokinetics of drugs in humans. However, residual murine enzymatic activities derived from the liver and presence of mouse small intestinal metabolism can hamper the prediction of human drug metabolism. We recently developed murine Cytochrome P450 3a gene knockout chimeric mice with humanized livers (Cyp3a KO CM). To evaluate the prediction of drug metabolism, nefazodone (NEF) was orally administered at 10 mg/kg to the following mice strains: Cyp3a KO CM, murine Cyp3a gene knockout (Cyp3a KO), PXB, and severe combined immunodeficiency (SCID) mice. Liquid chromatography-mass spectrometry was used for metabolic profiling of plasma, urine, and bile. Prediction of human metabolite levels such as hydroxy nefazodone (OH-NEF), triazoledione form (TD), m-chlorophenylpiperazine, and dealkyl metabolites in Cyp3a KO CM was superior to that in Cyp3a KO, PXB, or SCID mice. Further, clinical exposure levels of NEF, OH-NEF, and TD were reproduced in Cyp3a KO CM. In contrast, NEF was rapidly metabolized to TD in both PXB and SCID mice but not in Cyp3a KO mice, suggesting that murine CYP3A is involved in the elimination of NEF in these mice. These findings demonstrate that the metabolic profile of NEF in Cyp3a KO CM qualitatively and quantitatively differs from that in PXB mice due to the higher metabolic rate of NEF and its metabolites via murine CYP3A. Cyp3a KO CM might therefore be useful in predicting the metabolic profiles of drug candidates in humans. This article is protected by copyright. All rights reserved.
PMID: 26352195 [PubMed – as supplied by publisher]