Human pharmacogenetic analysis in chimeric mice with 'humanized livers'.

We investigated whether human pharmacogenetic factors could be characterized using chimeric NOG mice expressing a thymidine kinase transgene (TK-NOG) with 'humanized' livers. The rate of human-specific metabolism of two drugs was measured in chimeric mice reconstituted with human hepatocytes with different CYP2C19 and CYP2C9 genotypes. The rate of generation of human-predominant drug metabolites for S-mephenytoin and diclofenac in the chimeric mice was correlated with the CYP2C19 (n=9 donors, P=0.0005) or CYP2C9 (n=7 donors, P=0.0394) genotype, respectively, of the transplanted human hepatocytes. This study suggests that TK-NOG mice reconstituted with hepatocytes obtained from a relatively small number (3-10 per genotype) of human donors may be a promising model to identify human pharmacogenetic factors affecting the metabolism of clinically important drugs. For certain compounds, this innovative model system enables pharmacogenetic analyses to be efficiently performed in vivo within a human context and with control of all confounding environmental variables.