Establishment of an in vitro cholestasis risk assessment system using two-dimensional cultured HepaRG cells and 12 bile acids.

Drug-induced liver injury (DILI) is a major cause of market withdrawal or drug-development discontinuation because of safety concerns. In this study, we focused on drug-induced cholestasis (DIC) to establish an in vitro cytotoxicity test system and analyze its sensitivity using two-dimensional (2-D) cultured HepaRG cells and 12 types of bile acids (BAs) present in the human serum. First, to detect the cytotoxicity associated with cholestasis effectively, non-toxic BA concentrations were investigated and determined to be 100-fold the human serum value (455 µM total BAs). Next, the cytotoxicity of 31 compounds that can inhibit the bile acid export pump (BSEP) and were categorized as no-DILI-concern, less-DILI-concern, and most-DILI-concern was examined. None of the no-DILI-concern compounds yielded cytotoxicity, whereas almost all less-DILI-concern compounds (with the exception of simvastatin) and most-DILI-concern compounds (with the exception of bosentan) exhibited cytotoxicity. An investigation of the cause of cytotoxicity using 3H-taurocholic acid revealed that most-DILI-concern and less-DILI-concern compounds, but not no-DILI-concern compounds, triggered the accumulation of radioactivity in the cell lysates. Thus, the onset of cytotoxicity seemed to be associated with cholestasis. The established HepaRG cytotoxicity assessment system (sensitivity of 89%, specificity of 100%, and accuracy of 97%) was mostly superior to the Css/BSEP IC50 (> 0.1) assessment system (sensitivity of 83%, specificity of 100%, and accuracy of 72%). Therefore, the assay method using 2-D cultured HepaRG cells and 12 BAs established here can be widely applicable as a model for the in vitro potential assessment of DIC.

Severe and protracted cholestasis in 44 young men taking bodybuilding supplements: assessment of genetic, clinical and chemical risk factors.

BACKGROUND: Bodybuilding supplements can cause a profound cholestatic syndrome. AIM: To describe the drug-Induced liver injury network's experience with liver injury due to bodybuilding supplements. METHODS: Liver injury pattern, severity and outcomes, potential genetic associations, and exposure to anabolic steroids by product analysis were analysed in prospectively enrolled subjects with bodybuilding supplement-induced liver injury with causality scores of probable or higher. RESULTS: Forty-four males (mean age 33 years) developed liver injury with a median latency of 73 days. Forty-one per cent presented with hepatocellular pattern of liver injury as defined by the R > 5 ([Fold elevation of ALT] ÷ [Fold elevation of Alk Phos] (mean, range = 6.4, 0.5-31.4, n = 42) despite all presenting with clinical features of cholestatic liver injury (100% with jaundice and 84% with pruritus). Liver biopsy (59% of subjects) demonstrated a mild hepatitis and profound cholestasis in most without bile duct injury, loss or fibrosis. Seventy-one per cent were hospitalised, and none died or required liver transplantation. In some, chemical analysis revealed anabolic steroid controlled substances not listed on the label. No enrichment of genetic variants associated with cholestatic syndromes was found, although mutations in ABCB11 (present in up to 20%) were significantly different than in ethnically matched controls. CONCLUSIONS: Patients with bodybuilding supplements liver injury uniformly presented with cholestatic injury, which slowly resolved. The ingested products often contained anabolic steroids not identified on the label, and no enrichment in genetic variants was found, indicating a need for additional studies.

Assessment of cholestasis in drug-induced liver injury by different methods.

Cholestasis in drug-induced liver injury (DILI) can be assessed by biochemical and pathologic methods, but the agreement between the 2 methods remains unclear.The aim of this study was to identify the accurate method for assessment of cholestasis in DILI.The DILI standard established and revised by the Council for International Organizations of Medical Sciences (CIOMS) (R values were calculated by liver function at different time points), cholestatic liver disease guideline (European Association for the Study of the Liver, EASL), and liver pathology were used to assess, compare, and analyze the cholestasis in 133 patients with DILI.The R values at different time points in CIOMS standard had no statistical difference for the assessment of cholestatic DILI (a = 0.05, χ = 1.51, P = .679). There were statistical differences among the results of CIOMS, EASL, and pathology (a = 0.05, χ = 99.97, P < .001). EASL standard had no statistical difference with pathology (a = 0.003, χ = 8.00, P = .005).CIOMS and EASL standards based on biochemical parameters underestimated cholestatic DILI, as compared to liver pathology.

Mechanism-based risk assessment strategy for drug-induced cholestasis using the transcriptional benchmark dose derived by toxicogenomics.

Cholestasis is one of the major causes of drug-induced liver injury (DILI), which can result in withdrawal of approved drugs from the market. Early identification of cholestatic drugs is difficult due to the complex mechanisms involved. In order to develop a strategy for mechanism-based risk assessment of cholestatic drugs, we analyzed gene expression data obtained from the livers of rats that had been orally administered with 12 known cholestatic compounds repeatedly for 28 days at three dose levels. Qualitative analyses were performed using two statistical approaches (hierarchical clustering and principle component analysis), in addition to pathway analysis. The transcriptional benchmark dose (tBMD) and tBMD 95% lower limit (tBMDL) were used for quantitative analyses, which revealed three compound sub-groups that produced different types of differential gene expression; these groups of genes were mainly involved in inflammation, cholesterol biosynthesis, and oxidative stress. Furthermore, the tBMDL values for each test compound were in good agreement with the relevant no observed adverse effect level. These results indicate that our novel strategy for drug safety evaluation using mechanism-based classification and tBMDL would facilitate the application of toxicogenomics for risk assessment of cholestatic DILI.

Network-based Assessment on Chemical-induced Cholestatic Liver Injury.

The assessment of drug toxicity, especially hepatotoxicity, is a critical task in drug development process. To assist with early detection, various in silico approaches have been demonstrated to identify drugs with high hepatotoxicity potential. In this study, based on detailed review on previous reports on drug-induced cholestatic liver injury, we developed a network-based approach to predict cholestatic potential of chemicals using toxicogenomic data. First, the cholestasis network was constructed with 57 relevant genes and 78 connections between genes. Taking only genes in the disease network into account, the evaluation model was trained by genomic data of 17 typical chemicals associated with cholestasis and yielded the prediction accuracy at 88%. The performance of this model was further challenged by an X-permutation test and an external set of 98 chemicals. Among them, 14 chemicals were marked with high risk of inducing cholestasis by our approach. A survey of published literatures confirmed that 71.43% of our predicted chemicals have been shown to induce cholestatic liver injury experimentally and approximately 93% of them have been implicated to promote liver injury to various extents. Together, we concluded that network-based approaches greatly facilitate further understanding of molecular mechanisms for cholestatic liver injury and this concept could be easily generalized to other biological-relevant side-effect assessments.

Drug-induced cholestasis risk assessment in sandwich-cultured human hepatocytes.

Drug-induced cholestasis (DIC) is recognized as one of the prime mechanisms for DILI. Hence, earlier detection of drug candidates with cholestatic signature is crucial. Recently, we introduced an in vitro model for DIC and evaluated its performance with several cholestatic drugs. We presently expand on the validation of this model by 14 training compounds (TCs) of the EU-EFPIA IMI project MIP-DILI. Several batches of human hepatocytes in sandwich-culture were qualified for DIC assessment by verifying the bile acid-dependent increase in sensitivity to the toxic effects of cyclosporin A. The cholestatic potential of the TCs was expressed by determining the drug-induced cholestasis index (DICI). A safety margin (SM) was calculated as the ratio of the lowest TC concentration with a DICI≤0.80 to the Cmax,total. Nefazodone, bosentan, perhexiline and troglitazone were flagged for cholestasis (SM<30). The hepatotoxic (but non-cholestatic) compounds, amiodarone, diclofenac, fialuridine and ximelagatran, and all non-hepatotoxic compounds were cleared as "safe" for DIC. Tolcapone and paracetamol yielded DICI-based SM values equal to or higher than those based on cytotoxicity, thus excluding DIC as a DILI mechanism. This hepatocyte-based in vitro assay provides a unique tool for early and reliable identification of drug candidates with cholestasis risk.

Hepatocyte-based in vitro model for assessment of drug-induced cholestasis.

Early detection of drug-induced cholestasis remains a challenge during drug development. We have developed and validated a biorelevant sandwich-cultured hepatocytes- (SCH) based model that can identify compounds causing cholestasis by altering bile acid disposition. Human and rat SCH were exposed (24-48h) to known cholestatic and/or hepatotoxic compounds, in the presence or in the absence of a concentrated mixture of bile acids (BAs). Urea assay was used to assess (compromised) hepatocyte functionality at the end of the incubations. The cholestatic potential of the compounds was expressed by calculating a drug-induced cholestasis index (DICI), reflecting the relative residual urea formation by hepatocytes co-incubated with BAs and test compound as compared to hepatocytes treated with test compound alone. Compounds with clinical reports of cholestasis, including cyclosporin A, troglitazone, chlorpromazine, bosentan, ticlopidine, ritonavir, and midecamycin showed enhanced toxicity in the presence of BAs (DICI≤0.8) for at least one of the tested concentrations. In contrast, the in vitro toxicity of compounds causing hepatotoxicity by other mechanisms (including diclofenac, valproic acid, amiodarone and acetaminophen), remained unchanged in the presence of BAs. A safety margin (SM) for drug-induced cholestasis was calculated as the ratio of lowest in vitro concentration for which was DICI≤0.8, to the reported mean peak therapeutic plasma concentration. SM values obtained in human SCH correlated well with reported % incidence of clinical drug-induced cholestasis, while no correlation was observed in rat SCH. This in vitro model enables early identification of drug candidates causing cholestasis by disturbed BA handling.

[Antibiotic induced hepatotoxicity]. / Hépatotoxicité médicamenteuse due aux antibiotiques.

Drug-induced liver injury (DILI) is the most common cause of drug withdrawal of the market though it remains quite seldom. Actually, its incidence reaches about 1/100000 prescriptions. Antibiotics are the most implicated substances: 3 clinical cases are presented. The clinical manifestations are broad, appear between 5 to 90 days after the introduction of the drug and range from an asymptomatic patient to an acute hepatic failure. This diagnosis is difficult to establish. After excluding a biliary obstruction and a septic cholangitis at first, many additional investigations can be performed, but induce considerable costs. Drug history is the key element of the diagnostic approach. An algorithm is presented at the end of this article to prevent expensive, invasive and useless investigations.

Assessment of hepatic function in rabbits with steroid-induced cholestatic liver injury.

Methyltestosterone (MT) or ethinyl estradiol (EE) was administered to adult rabbits for 20 weeks beginning with initial daily doses of 0.4 mg/kg MT and 0.015 mg/kg EE for three weeks, then these dosages were doubled at 3-week intervals to a maximum dosages 6.4 mg/kg and 0.24 mg/kg, respectively. Within 2 weeks, the serum gamma-glutamyltransferase activity of MT and EE treated rabbits was significantly greater than controls and increased progressively throughout the treatment period. Aspartate aminotransferase activity was also increased at 2 weeks and remained so for 17 weeks. Serum alkaline phosphatase was elevated at 2 weeks but thereafter was normal indicating that this enzyme is of no value in detecting steroid-induced hepatic dysfunction. Elevated serum bile acid concentration and prolonged BSP clearance indicated marked hepatic excretory dysfunction at higher dose levels. Histologic abnormalities were observed in the livers of both MT and EE treated rabbits. These lesions were more severe in the EE group in which there was marked bile duct proliferation, mononuclear cell infiltration of portal areas, and perilobular fibrosis. The studies indicate that the rabbit is susceptible to development of hepatic injury when receiving 17 alpha-alkyl substituted steroids and may be a useful animal model for investigations of the pathogenesis of steroid-induced cholestatic liver injury.

Contraception.

PIP: The article reviews the putative effects of oral contraceptives on the metabolism, hepatic function, thyroid gland, adrenal gland, carbohydrate and lipid metabolism, blood pressure and coagulation, and thromboembolic disease. Assessing risks by interpretation of mortality rates is briefly discussed and it is concluded that the risks in oral contraception are acceptable.^ieng