Human precision-cut liver slices as an ex vivo model to study idiosyncratic drug-induced liver injury

Idiosyncratic drug-induced liver injury (IDILI) is a major problem during drug development and has caused drug withdrawal and black-box warnings. Due to the low concordance of the hepatotoxicity of drugs in animals and humans, robust screening methods using human tissue are needed to predict and to develop biomarkers for IDILI in human . According to the inflammatory stress hypothesis, the effects of inflammation interact with the effects of a drug or its reactive metabolite(s) precipitating the toxic reactions to the liver. As a follow–up of our recently published mouse precision-cut liver slices (PCLS) model1, an ex vivo model involving human precision-cut liver slices (hPCLS), co-incubated for 24h with IDILI-related drugs (clozapine, ketoconazole, diclofenac, troglitazone, carbamazepine) and lipopolysaccharide (LPS), was developed to study IDILI mechanisms related to inflammatory stress in humans and to detect potential biomarkers. As comparator non-IDILI-related drugs voriconazole and olanzapine were included. LPS induced the production of inflammatory and anti-inflammatory cytokines, whereas none of the drugs caused a cytokine release. LPS exacerbated the toxicity of ketoconazole and clozapine but not of their non-IDILI-related comparators, voriconazole and olanzapine. However, the IDILI-related drugs diclofenac, carbamazepine and troglitazone did not show synergistic toxicity with LPS after 24h incubation. Coincubation of ketoconazole and clozapine with LPS decreased the glutathione levels in hPCLS, which did not occur with the other drugs. All drugs affected LPS-induced cytokine release, but interestingly, only ketoconazole and clozapine increased the LPS-induced TNF release. Decreased glutathione- and cysteine-conjugates of clozapine were detected in IDILI-responding livers following cotreatment with LPS. In conclusion, we identified ketoconazole and clozapine as drugs that exhibited synergistic toxicity with LPS, while glutathione and TNF were found to be potential biomarkers for IDILI-inducing drugs mediated by inflammatory stress. hPCLS appear suitable to further unravel the mechanisms of inflammatory stress-associated IDILI.