title: CYP2C9-catalyzed metabolism of S-warfarin to 7-hydroxywarfarin in vivo and in vitro in chimeric mice with humanized liver.
abstract: Chimeric mice having humanized livers were constructed by transplantation of human hepatocytes. In this study, we investigated whether these mice have a capacity for drug metabolism similar to that of humans by examining hydroxylation of S-warfarin, which is predominantly metabolized to S-7-hydroxywarfarin, catalyzed by CYP2C9, in humans but not mice. The 7-hydroxylating activity of chimeric mouse liver microsomes toward S-warfarin was approximately 10-fold higher than that of control (urokinase-type plasminogen activator-transgenic severe combined immunodeficient) mice. The 7-hydroxylase activity of chimeric mouse liver microsomes was markedly inhibited by sulfaphenazole, as was that of human liver microsomes, whereas the activity of control mice was unaffected. The CYP2C isoform in chimeric mouse liver was also confirmed to be the human isoform, CYP2C9, by immunoblot analysis. In the present in vivo study, the level of S-7-hydroxywarfarin in plasma of chimeric mice was approximately 7-fold higher than that in control mice, in agreement with the in vitro data. Thus, the CYP2C isoform in chimeric mice functions in vivo and in vitro as a human isoform, CYP2C9. These results suggest that chimeric mice with humanized liver could be useful for predicting drug metabolism in humans, at least regarding CYP2C9-dependent metabolism.
authors.affiliation: Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Tae
authors.initials: T
authors.lastname: Inoue
authors.forename: Kayoko
authors.initials: K
authors.lastname: Nitta
authors.forename: Kazumi
authors.initials: K
authors.lastname: Sugihara
authors.forename: Toru
authors.initials: T
authors.lastname: Horie
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kitamura
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ohta
mesh_terms: D000293:Adolescent; D000818:Animals; D019540:Area Under Curve; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D065729:Cytochrome P-450 CYP2C9; D022781:Hepatocytes / Q000637:transplantation; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D016513:Mice, SCID; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D013426:Sulfaphenazole / Q000494:pharmacology; D018183:Transplantation Chimera / Q000097:blood / Q000378:metabolism*; D014859:Warfarin / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics
chemical_list: D013426:Sulfaphenazole; D014859:Warfarin; C087837:7-hydroxywarfarin; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases