A Novel in Vitro Liver Cell Culture Flow System Allowing Long-Term Metabolism and Hepatotoxicity Studies

Abstract

Introduction: Hepatotoxicity is a concern when developing new pharmaceutical compounds. Animal models do not accurately predict toxicity in humans due to species differences, for example, in compound metabolism. In this study, we present an alternative in vitro model based on the culture of primary human hepatocytes (PHH) in the Quasi Vivo® QV900 Flow System. Materials and Methods: PHH were kept in sandwich culture in static and in perfused conditions. During 3 weeks of culture, viability and albumin content were quantified. Basal and induced cytochrome P450 (CYP) enzyme activity were assessed by luminescence assay and analysis of metabolite formation. Results: Good cell viability and sustained albumin production were observed in perfused culture. In comparison to nonperfused cultures, the basal activity of the drug metabolism enzymes CYP3A4, CYP1A2, and CYP2B6 was increased. Induced CYP3A4 activity was comparable between perfused and nonperfused cultures. Furthermore, the QV900 System allowed fewer medium changes as typically required in static cultures. This enables buildup of potential toxic metabolites that would otherwise not be detected when media are refreshed daily. Discussion: PHH can be cultured in the QV900 Flow System for 3 weeks with only two medium changes per week. Improved basal CYP activity was observed in comparison to static culture. Conclusion: We present a liver cell culture flow system that improves longer-term stability of drug metabolism enzymes in PHH and is therefore a more human-relevant in vitro model for repeat dosing of hepatotoxicants.