BACKGROUND:?The bioartiifcial liver is anticipated to be a promising alternative choice for patients with liver failure. Toxic substances which accumulate in the patients' plasma exert deleterious effects on hepatocytes in the bioreactor, and potentially reduce the efifcacy of bioartiifcial liver devices. This study was designed to investigate the effects of plasma from patients with acute on chronic liver failure (AoCLF) on immortalized human hepatocytes in terms of cytochrome P450 gene expression, drug metabolism activity and detoxiifcation capability. METHODS:?Immortalized human hepatocytes (HepLi-2 cells) were cultured in medium containing fetal calf serum or human plasma from three patients with AoCLF. The cytochrome P450 (CYP3A5, CYP2E1, CYP3A4) expression, drug metabolism activity and detoxiifcation capability of HepLi-2 cells were assessed by RT-PCR, lidocaine clearance and ammonia elimination assay. RESULTS:?After incubation in medium containing AoCLF plasma for 24 hours, the cytochrome P450 mRNA expression of HepLi-2 cells was not signiifcantly decreased compared with control culture. Ammonia elimination and lidocaine clearance assay showed that the ability of ammonia removal and drug metabolism remained stable. CONCLUSIONS:?Immortalized human hepatocytes can be exposed to AoCLF plasma for at least 24 hours with no signiifcant reduction in the function of cytochrome P450. HepLi-2 cells appear to be effective in metabolism and detoxiifcation and can be potentially used in the development of bioartiifcial liver.