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Induction, expression and maintenance of cytochrome P450 isoforms in long-term cultures of primary human hepatocytes.

Within the past decade, tremendous progress has been made in the isolation and culture of human hepatocytes for drug metabolism and toxicology, which could potentially reduce the number of animal experiments performed. However, human hepatocyte cultures are still not widely used for preclinical drug testing, partly due to inconsistent supply and quality of human tissue. Thus, the aim of this study was to evaluate primary cultured human hepatocytes from different patients over a study period of 14 days, by assays that characterise cell quality and function. We found urea production and albumin synthesis in all cell cultures over at least 7 days. Cytochrome P4501A2, CYP2D6, and CYP3A4 protein expression was demonstrated by Western Blot analysis and CYP1A1/2 and CYP3A4 induction by 3-methylcholantrene, phenobarbital or rifampicin over 14 days. In addition, we saw that UDP-glucoronyltransferase activity was preserved in human hepatocytes over 2 weeks. In conclusion, we could show that primary human hepatocytes isolated from discarded liver tissue can consistently be kept in culture over a long time period and are therefore well suited for preclinical drug testing.