Insights from a novel in vitro cigarette smoke induction model: comparison of 24 primary human hepatocyte donors of diverse demographics and multiple sources.

Cigarette smoking induces cytochrome P450 (CYP) enzymes, causing significant drug interactions. To evaluate such interactions prior to clinical studies, an in vitro model was developed by Lenich and Ruez  (2025) in primary human hepatocytes. Because smoking affects patients worldwide with diverse genetic and environmental backgrounds, it is essential that this model can reflect population variability. This study aimed to apply the smoke induction model to 24 hepatocyte donors from various backgrounds, to validate the model´s reproducibility and enhance its clinical relevance. mRNA expression of CYP1A1, CYP1A2, CYP2C8, CYP2B6, and CYP3A4, along with CYP1A1 and CYP1A enzyme activity, was measured. CYP enzymes were induced (concentration-dependent increase ≥ 2-fold) in all donors, exhibiting a consistent induction pattern, with CYP1A1 mRNA expression and enzyme activity showing the highest response (10-225-fold and 12-334-fold, respectively). CYP1A2 mRNA expression was induced in all donors, CYP1A enzyme activity in 14 donors, CYP2C8 mRNA in 10 donors, CYP2B6 mRNA in 18 donors and CYP3A4 mRNA in 15 donors. Induction capacity was correlated to donor characteristics, including supplier, gender, ethnicity, smoking status, alcohol and drug abuse. No significant correlations were identified with demographic or lifestyle factors. However, a significant difference in CYP1A2 mRNA induction was observed between suppliers, with BioIVT donors exhibiting higher responses. In conclusion, CSE consistently induced CYP enzymes across 24 donors, demonstrating the robustness of the smoke induction model and its suitability to reflect patient variability in clinical studies.