采用斑马鱼模型评价对乙酰氨基酚的肝脏毒性

目的研究对乙酰氨基酚（APAP）对斑马鱼幼鱼的肝脏毒性,并验证斑马鱼模型用于药物肝毒性快速评价的实用性。方法以发育72 hpf的肝脏荧光转基因斑马鱼幼鱼（L-FABP：EGFP）为实验对象,不同浓度的APAP分别处理斑马鱼幼鱼,于处理后24、48、72 h,体视显微镜下观察幼鱼的死亡率、肝脏形态学变化和卵黄囊吸收情况,荧光显微镜下观察APAP对幼鱼肝脏荧光的影响。结果 APAP对斑马鱼幼鱼存活率的影响呈剂量和时间相关性。APAP处理后的幼鱼肝脏形态出现异常、肝脏颜色变暗,卵黄囊肿。与空白对照组相比,APAP处理后的幼鱼肝组织L-FABP荧光表达明显下降,肝脏明显萎缩退化。结论 APAP对斑马鱼幼鱼具有肝脏毒性。肝脏荧光转基因斑马鱼模型快速评价药物的肝脏毒性具有较好的应用前景。     

基于斑马鱼模型评价注射用益气复脉（冻干）的心血管和肝脏安全性研究

目的 应用斑马鱼模型评价注射用益气复脉（冻干）（YQFM）的心血管毒性和肝毒性。方法 受精后48 h的野生型AB系斑马鱼随机分为空白对照组（未注射组）、溶剂对照组（注射0.9%氯化钠注射液10 nL）和YQFM 10、20、100、200、400、600、800和1 000 ng组,iv给药4 h后统计各剂量组斑马鱼死亡数量,计算最大非致死剂量（MNLD）和10%致死剂量（LD₁₀）值。心血管毒性和肝毒性评价剂量设置为MNLD/10（20 ng）、MNLD/3（60 ng）、MNLD（200 ng）和LD₁₀（400 ng）;在显微镜下观察YQFM对斑马鱼心率的影响,观察斑马鱼有无心包水肿、血流速度变化、血液流失、心包瘀（出）血、血栓等,计算各表型发生率;在显微镜下对肝脏进行观察,对典型表型进行拍照,利用分析软件NIS-ElementsD 3.10分析肝脏面积、肝脏不透光度和卵黄囊面积。结果 YQFM MNLD和LD₁₀分别为198.06 ng（约为200 ng）和397.12 ng（为400 ng）;与溶剂对照组比较,YQFM 20、60 ng组斑马鱼未见异常,没有观察到心血管毒性,未见心包水肿,未见心率减慢,未见心律不齐;YQFM 200 ng组斑马鱼出现发生率较低的心血管毒性,表现为心包水肿（发生率仅为3.3%）,未见心率减慢,未见心律不齐;400 ng组斑马鱼出现较轻微的心血管毒性,表现为心包水肿（发生率为13.3%）、血流变慢（发生率为6.7%）、血流缺失（发生率3.3%）,未见心率减慢,未见心律不齐。与溶剂对照组比较,YQFM各剂量（20、60、200、400 ng）组斑马鱼相对肝脏大小、肝脏不透光度平均值和卵黄囊延迟吸收倍数均无统计学差异。结论 YQFM在MNLD剂量下,不诱发斑马鱼心血管毒性和肝脏毒性。     

Human cardiotoxic drugs delivered by soaking and microinjection induce cardiovascular toxicity in zebrafish

Cardiovascular toxicity is a major challenge for the pharmaceutical industry and predictive screening models to identify and eliminate pharmaceuticals with the potential to cause cardiovascular toxicity in humans are urgently needed. In this study, taking advantage of the transparency of larval zebrafish, Danio rerio, we assessed cardiovascular toxicity of seven known human cardiotoxic drugs (aspirin, clomipramine hydrochloride, cyclophosphamide, nimodipine, quinidine, terfenadine and verapamil hydrochloride) and two non‐cardiovascular toxicity drugs (gentamicin sulphate and tetracycline hydrochloride) in zebrafish using six specific phenotypic endpoints: heart rate, heart rhythm, pericardial edema, circulation, hemorrhage and thrombosis. All the tested drugs were delivered into zebrafish by direct soaking and yolk sac microinjection, respectively, and cardiovascular toxicity was quantitatively or qualitatively assessed at 4 and 24 h post drug treatment. The results showed that aspirin accelerated the zebrafish heart rate (tachycardia), whereas clomipramine hydrochloride, cyclophosphamide, nimodipine, quinidine, terfenadine and verapamil hydrochloride induced bradycardia. Quinidine and terfenadine also caused atrioventricular (AV) block. Nimodipine treatment resulted in atrial arrest with much slower but regular ventricular heart beating. All the tested human cardiotoxic drugs also induced pericardial edema and circulatory disturbance in zebrafish. There was no sign of cardiovascular toxicity in zebrafish treated with non‐cardiotoxic drugs gentamicin sulphate and tetracycline hydrochloride. The overall prediction success rate for cardiotoxic drugs and non‐cardiotoxic drugs in zebrafish were 100% (9/9) as compared with human results, suggesting that zebrafish is an excellent animal model for rapid in vivo cardiovascular toxicity screening. The procedures we developed in this report for assessing cardiovascular toxicity in zebrafish were suitable for drugs delivered by either soaking or microinjection. Copyright © 2013 John Wiley & Sons, Ltd.     

Development of a cell-based assay system considering drug metabolism and immune- and inflammatory-related factors for the risk assessment of drug-induced liver injury

Drug-induced liver injury (DILI) is a major safety concern in drug development and clinical pharmacotherapy. However, prediction of DILI is difficult because the underlying mechanisms are not fully understood. To establish a novel cell-based screening system to suggest drugs with hepatotoxic potential in preclinical drug development, comprehensive gene expression analyses during in vivo DILI are necessary. Using in vivo mouse DILI models and 4 sets of hepatotoxic positive and non-hepatotoxic drugs, we found that the hepatic mRNA levels of S100A8; S100A9; “NATCH, LRR, and pyrin domain-containing protein 3” (NALP3); interleukin (IL)-1β; and the receptor for advanced glycation endproducts (RAGE) were commonly increased in hepatotoxic drug-administered mice compared to non-hepatotoxic drug-administered mice. To clarify whether these 5 in vivo biomarkers can be applied to a cell-based screening system, we adapted human liver microsomes (HLM) in the presence of NADPH to assess the metabolic activation reaction, and we also adapted human monocytic leukemia cells HL-60, K562, KG-1 and THP-1 to assess the effects on mRNA expression of immune- and inflammatory-related factors. We investigated 30 clinical drugs with different safety profiles with regard to DILI and found that the total sum score of gene expression levels of S100A8, S100A9, RAGE, NALP3 and IL-1β mRNA in HL-60 or K562 cells incubated with HLM, could identify drugs at high risk for hepatotoxicity. We proposed the use of the total sum score of gene expression level for assessing metabolic activation by drug-metabolizing enzymes and immune- and inflammatory-related factors for the risk assessment of DILI in preclinical drug development.     

Proteomics in the search for mechanisms and biomarkers of drug-induced hepatotoxicity

The safety assessment for pharmaceuticals includes in vivo repeated dose toxicity tests in laboratory animals. These in vivo studies often generate false negative results and unexpected toxicity. The appearance of this unexpected toxicity is one of the major reasons for the drawback of a drug from the market. The liver is often a target organ in toxicology since it is responsible for the metabolism and elimination of chemical compounds. Therefore, there is need for new screening methods which classify hepatotoxic compounds earlier in development. This will lead to safer drugs and a more efficient drug discovery process. Furthermore, these new screening methods are preferably in vitro test systems, aiming at reducing the use of laboratory animals. In this review the possibilities of proteomics and its promising results for improving current predictive and mechanistic toxicological studies are described. Biomarkers or protein panels for hepatotoxic mechanisms, which reflect the in vivo situation, need to be identified to allow a better toxicity screening. Therefore, in vivo studies and in vitro cell models are discussed and evaluated with regard to the protein expression of their metabolic enzymes, their similarities with liver, their use for analyzing toxicological mechanisms and hepatotoxicity screening. Studies in which proteomics are combined with other omics-technologies are also presented. The results from these integrated data analyses can be used for the development of improved panels of biomarkers for toxicity screening.     

Zebrafish as model organisms for studying drug-induced liver injury

Drug-induced liver injury (DILI) is a major challenge in clinical medicine and drug development. New models are needed for predicting which potential therapeutic compounds will cause DILI in humans, and new markers and mediators of DILI still need to be identified. This review highlights the strengths and weaknesses of using zebrafish as a high-throughput in vivo model for studying DILI. Although the zebrafish liver architecture is different from that of the mammalian liver, the main physiological processes remain similar. Zebrafish metabolize drugs using similar pathways to those in humans; they possess a wide range of cytochrome P450 enzymes that enable metabolic reactions including hydroxylation, conjugation, oxidation, demethylation and de-ethylation. Following exposure to a range of hepatotoxic drugs, the zebrafish liver develops histological patterns of injury comparable to those of mammalian liver, and biomarkers for liver injury can be quantified in the zebrafish circulation. The zebrafish immune system is similar to that of mammals, but the zebrafish inflammatory response to DILI is not yet defined. In order to quantify DILI in zebrafish, a wide variety of methods can be used, including visual assessment, quantification of serum enzymes and experimental serum biomarkers and scoring of histopathology. With further development, the zebrafish may be a model that complements rodents and may have value for the discovery of new disease pathways and translational biomarkers.     

Are zebrafish larvae suitable for assessing the hepatotoxicity potential of drug candidates?

Drug‐induced liver injury (DILI) is poorly predicted by single‐cell‐based assays, probably because of the lack of physiological interactions with other cells within the liver. An intact whole liver system such as one present in zebrafish larvae could provide added value in a screening strategy for DILI; however, the possible occurrence of other organ toxicities and the immature larval stage of the zebrafish might complicate accurate and fast analysis. We investigated whether expression analysis of liver‐specific fatty acid binding protein 10a (lfabp10a) was an appropriate endpoint for assessing hepatotoxic effects in zebrafish larvae. It was found that expression analysis of lfabp10a was a valid marker, as after treatment with hepatotoxicants, dose–response curves could be obtained and statistically significant abnormal lfabp10 expression levels correlated with hepatocellular histopathological changes in the liver. However, toxicity in other vital organs such as the heart could impact liver outgrowth and thus had to be assessed concurrently. Whether zebrafish larvae were suitable for assessing human relevant drug‐induced hepatotoxicity was assessed with hepatotoxicants and non‐hepatotoxicants that have been marketed for human use and classified according to their mechanism of toxicity. The zebrafish larva showed promising predictivity towards a number of mechanisms and was capable of distinguishing between hepatotoxic and non‐hepatotoxic chemical analogues, thus implying its applicability as a potential screening model for DILI. Copyright © 2015 John Wiley & Sons, Ltd.     

基于斑马鱼模型的中药致肝脏毒性评价的研究进展

中药的广泛使用,提高了肝脏毒性发生风险。斑马鱼模型在肝脏毒性研究中显现出较大潜力的同时,也面临评价标准难以统一的问题。在使用斑马鱼进行药物肝损伤检测和评价之前应先明确其在不同生长阶段的肝功能状态,利用斑马鱼胚胎和幼鱼的通体透明的特点,以胚胎的孵化率、死亡率、畸形率作出初步的发育毒性判断,以幼鱼肝脏灰度值,肝脏面积大小,卵黄囊吸收程度作为药物是否具有肝脏毒性的判断标准,利用成鱼肝脏容易分离的特点研究肝脏毒性的作用机制。检测时可根据这些指标判断斑马鱼肝脏发育阶段,为其是否发生药物肝损伤提供依据,从而进一步提高临床用药安全性。综述了不同发育时期斑马鱼评估中药肝毒性的研究方法及研究进展,以期为后续中药的肝脏毒性评价提供参考。     

Toxicity prediction of compounds from turmeric (Curcuma longa L)

Turmeric belongs to the ginger family Zingiberaceae. Currently, cheminformatics approaches are not employed in any of the spices to study the medicinal properties traditionally attributed to them. The aim of this study is to find the most efficacious molecule which does not have any toxic effects. In the present study, toxicity of 200 chemical compounds from turmeric were predicted (includes bacterial mutagenicity, rodent carcinogenicity and human hepatotoxicity). The study shows out of 200 compounds, 184 compounds were predicted as toxigenic, 136 compounds are mutagenic, 153 compounds are carcinogenic and 64 compounds are hepatotoxic. To cross validate our results, we have chosen the popular curcumin and found that curcumin and its derivatives may cause dose dependent hepatotoxicity. The results of these studies indicate that, in contrast to curcumin, few other compounds in turmeric which are non-mutagenic, non-carcinogenic, non-hepatotoxic, and do not have any side-effects. Hence, the cost-effective approach presented in this paper could be used to filter toxic compounds from the drug discovery lifecycle.     

Mechanism-based selection of compounds for the development of innovative in vitro approaches to hepatotoxicity studies in the LIINTOP project

The 6th European Framework Programme project LIINTOP was specifically raised to optimise and provide established protocols and experimental in vitro models for testing intestinal and liver absorption, metabolism and toxicity of molecules of pharmacological interest. It has been focused on some of the most promising existing liver and intestine in vitro models with the aim of further improving their performance and thus taking them to a pre-normative research stage. Regarding the specific area of the liver, a first basic approach was the optimisation of in vitro hepatic models and the development and optimisation of in vitro approaches for toxicity screening. New advanced technologies have been proposed and developed in order to determine cellular and molecular targets as endpoints of drug exposure. A key issue in the development and optimisation of in vitro hepatotoxicity screening methods was the selection of structurally diverse suitable hepatotoxic reference model compounds to be tested. To this end, a number of solid selection criteria were defined (drugs preferably than chemical agents, well-documented hepatotoxicity in man and well-defined mechanism/s of hepatotoxicity, commercially available no volatile compounds with unequivocal CAS number and chemical structure), the strategy followed, including all resources consulted, is described and the selected compounds are extensively illustrated.     

Developmental toxicity,EROD, and CYP1A mRNA expression in zebrafish embryos exposed to dioxin‐like PCB126

Dioxin‐like PCB126 is a persistent organic pollutant that causes a range of syndromes including developmental toxicity. Dioxins have a high affinity for aryl hydrocarbon receptor (AhR) and induce cytochrome P4501A (CYP1A). However, the role of CYP1A activity in developmental toxicity is less clear. To better understand dioxin induced developmental toxicity, we exposed zebrafish (Danio rerio) embryos to PCB126 at concentrations of 0, 16, 32, 64, and 128 μg L^?1 from 3‐h post‐fertilization (hpf) to 168 hpf. The embryonic survival rate decreased at 144 and 168 hpf. The fry at 96 hpf displayed gross developmental malformations, including pericardial and yolk sac edema, spinal curvature, abnormal lower jaw growth, and non‐inflated swim bladder. The pericardial and yolk sac edema rate significantly increased and the heart rate declined from 96 hpf compared with the controls. PCB126 did not alter the hatching rate. To elucidate the mechanism of PCB126‐induced developmental toxicity, we conducted ethoxyresorufin‐O‐deethylase (EROD) in vivo assay to determine CYP1A enzyme activity, and real‐time PCR to study the induction of CYP1A mRNA gene expression in embryo/larval zebrafish at 24, 72, 96, and 132 hpf. In vivo EROD activity was induced by PCB126 at 16 μg L^?1 concentration as early as 72 hpf but significant increases were observed only in zebrafish exposed to 64 and 128 μg L^?1 doses (p < 0.005) at 72, 96, and 132 hpf. Induction of CYP1A mRNA expression was significantly upregulated in zebrafish exposed to 32 and 64 μg L^?1 at 24, 72, 96, and 132 hpf. Overall, the severe pericardial and yolk sac edema and reduced heart rate suggest that heart defects are a sensitive endpoint, and the general trend of dose‐dependent increase in EROD activity and induction of CYP1A mRNA gene expression provide evidence that the developmental toxicity of PCB126 to zebrafish embryos is mediated by activation of AhR. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 201–210, 2016.     

Identification of in vitro protein biomarkers of idiosyncratic liver toxicity.

Drug-induced idiosyncratic hepatotoxicity continues to be an important safety issue for the pharmaceutical industry. This toxicity is due, in part, to the limited predictive nature of current pre-clinical study systems. A hypothesis was formed that treatment of existing in vitro hepatocyte cultures with drugs clinically linked to idiosyncratic hepatotoxicity would result in the release of extracellular protein biomarkers indicative of liver toxicity. To test this hypothesis, a combination of proteomic and immunological techniques were used to first identify, and subsequently verify, components of the protein-laden conditioned culture media from immortalized human hepatocytes which overexpressed cytochrome p450 3A4. These cells were treated separately with seven individual compounds made up of a combination of thiazolidinedione and l-tyrosine PPARgamma agonists and HIV protease inhibitors, plus a vehicle control (dimethyl sulfoxide). For each drug class, clinically determined hepatotoxic and non-hepatotoxic compounds were compared. Two proteins, BMS-PTX-265 and BMS-PTX-837, were reproducibly and significantly increased in the conditioned media from cells treated with each of the toxic compounds as compared to media from cells treated with the non-toxic compounds (and vehicle). This result supported the hypothesis, and so a series of successive assays (western blots and enzyme linked immunosorbent assays) were used to measure the response of these two proteins as a function of an expanded set of 20 compounds. For all 20 drugs, elevations of BMS-PTX-265 correlated exactly with the known safety profile; whereas changes in BMS-PTX-837 correctly predicted the safety profile in 19 of 20 drugs (one false negative). In summary, the data supports both the pre-clinical in vitro method as a means to identify new biomarkers of liver toxicity, as well as the validity of the biomarkers themselves.     

Drug-induced hepatotoxicity in cancer patients - implication for treatment

ABSTRACT

Introduction: All anticancer drugs can cause idiosyncratic liver injury. Therefore, hepatoprotective agents assume particular importance to preserve liver function. Hepatic injury represents 10% of cases of acute hepatitis in adults; drug-related damage is still misjudged because of relative clinical underestimation and difficult differential diagnosis. Chemotherapeutic agents can produce liver toxicity through different pathways, resulting in different categories of liver injuries, but these drugs are not homogeneously hepatotoxic. Frequently, anticancer-induced hepatotoxicity is idiosyncratic and influenced by multiple factors.

Areas covered: The aim of this paper is to perform a review of the literature regarding anticancer-induced liver toxicity. We described hepatotoxicity mechanisms of principal anticancer agents and respective dose reductions. Furthermore, we reviewed studies on hepatoprotectors and their optimal use. Tiopronin, magnesium isoglycyrrhizinate and S-Adenosylmethionine (AdoMet) demonstrated, in some small studies, a potential hepatoprotective activity.

Expert Opinion: Actually, in the literature only small experiences are reported. Even though hepatoprotective agents seem to be useful in the oncologic setting, the lack of well-designed prospective Phase III randomized controlled trials is a major limit in the introduction of hepatoprotectors in cancer patients and these kind of studies are warranted to support their use and to give further recommendations for the clinical practice.     

In Vitro and In Vivo Toxicity Evaluation of Natural Products with Potential Applications as Biopesticides

The use of natural products in agriculture as pesticides has been strongly advocated. However, it is necessary to assess their toxicity to ensure their safe use. In the present study, mammalian cell lines and fish models of the zebrafish (Danio rerio) and medaka (Oryzias latipes) have been used to investigate the toxic effects of ten natural products which have potential applications as biopesticides. The fungal metabolites cavoxin, epi-epoformin, papyracillic acid, seiridin and sphaeropsidone, together with the plant compounds inuloxins A and C and ungeremine, showed no toxic effects in mammalian cells and zebrafish embryos. Conversely, cyclopaldic and α-costic acids, produced by Seiridium cupressi and Dittrichia viscosa, respectively, caused significant mortality in zebrafish and medaka embryos as a result of yolk coagulation. However, both compounds showed little effect in zebrafish or mammalian cell lines in culture, thus highlighting the importance of the fish embryotoxicity test in the assessment of environmental impact. Given the embryotoxicity of α-costic acid and cyclopaldic acid, their use as biopesticides is not recommended. Further ecotoxicological studies are needed to evaluate the potential applications of the other compounds.     

红霉素和阿奇霉素诱导斑马鱼肝毒性及作用机制研究

目的 利用模式生物斑马鱼模型探索红霉素和阿奇霉素导致肝毒性及作用机制,并比较红霉素和阿奇霉素诱导肝毒性的差异。方法 选用肝脏转基因斑马鱼Tg(fapb10: dsRed)作为实验动物,将发育正常的3dpf斑马鱼幼鱼暴露于不同浓度的红霉素和阿奇霉素溶液中72h后,统计各组斑马鱼死亡率,计算红霉素和阿奇霉素对斑马鱼的LD50;荧光显微镜下活体观察斑马鱼幼鱼给药后肝脏形态的变化;采用整体油红O染色观察肝脏脂肪含量变化;利用qRT-PCR检测肝脏病理标志基因和凋亡相关基因在转录水平的变化。结果 红霉素和阿奇霉素对斑马鱼的LD50分别为3.82mmol/L和3.10mmol/L;活体观察显示红霉素和阿奇霉素均能导致幼鱼肝脏形态和荧光强度变化;整体油红O染色显示红霉素和阿奇霉素均能导致肝细胞脂肪堆积,并呈剂量依赖性;qRT-PCR结果显示红霉素和阿奇霉素均能影响脂肪肝、肝纤维化和细胞凋亡相关基因的表达。结论 红霉素和阿奇霉素均能诱导斑马鱼肝毒性,作用机制可能与两者诱导肝细胞变性或凋亡有关,但两者影响的相关基因通路可能有所不同。     

毒结清丸对斑马鱼的急性毒性及其肝脏毒性评价

目的：开展毒结清丸对斑马鱼的急性毒性试验及其肝脏毒性评价,为毒结清丸在临床用药安全方面提供实验依据。方法：将3 dpf野生型AB品系斑马鱼暴露在不同浓度毒结清丸水溶液中,绘制最佳"浓度-死亡率"效应曲线,计算毒结清丸对斑马鱼的最大非致死浓度（MNLC）和LC₁₀,并对其急性毒性进行评价;通过分析斑马鱼肝脏面积、肝脏不透光度、卵黄囊面积和肝脏病理切片来评价毒结清丸对斑马鱼的肝脏毒性。结果：毒结清丸对斑马鱼的MNLC为674 μg·mL^-1,LC₁₀为741 μg·mL^-1,毒性靶器官为肝脏;毒结清丸对斑马鱼肝脏面积和肝脏不透光度均没有明显影响,674 μg·mL^-1和741 μg·mL^-1质量浓度组可诱发斑马鱼卵黄囊吸收延迟;肝脏病理学分析显示,给药组与正常对照组相似,未见明显异常。结论：在MNLC和LC₁₀的浓度下,毒结清丸仅引起卵黄囊吸收延迟;斑马鱼肝脏面积、肝脏不透光度和肝脏病理切片未见明显异常。     

Validation of visualized transgenic zebrafish as a high throughput model to assay bradycardia related cardio toxicity risk candidates

Drug‐induced QT prolongation usually leads to torsade de pointes (TdP), thus for drugs in the early phase of development this risk should be evaluated. In the present study, we demonstrated a visualized transgenic zebrafish as an in vivo high‐throughput model to assay the risk of drug‐induced QT prolongation. Zebrafish larvae 48 h post‐fertilization expressing green fluorescent protein in myocardium were incubated with compounds reported to induce QT prolongation or block the human ether‐a‐go‐go‐related gene (hERG) K⁺ current. The compounds sotalol, indapaminde, erythromycin, ofoxacin, levofloxacin, sparfloxacin and roxithromycin were additionally administrated by microinjection into the larvae yolk sac. The ventricle heart rate was recorded using the automatic monitoring system after incubation or microinjection. As a result, 14 out of 16 compounds inducing dog QT prolongation caused bradycardia in zebrafish. A similar result was observed with 21 out of 26 compounds which block hERG current. Among the 30 compounds which induced human QT prolongation, 25 caused bradycardia in this model. Thus, the risk of compounds causing bradycardia in this transgenic zebrafish correlated with that causing QT prolongation and hERG K⁺ current blockage in established models. The tendency that high logP values lead to high risk of QT prolongation in this model was indicated, and non‐sensitivity of this model to antibacterial agents was revealed. These data suggest application of this transgenic zebrafish as a high‐throughput model to screen QT prolongation‐related cardio toxicity of the drug candidates. Copyright © 2012 John Wiley & Sons, Ltd.     

Increased sensitivity for troglitazone-induced cytotoxicity using a human in vitro co-culture model

Drug-induced hepatotoxicity is a major reason for withdrawal of drugs from development as well as from the market. A major problem predicting hepatotoxicity is the lack of suitable predictive in vitro system. Drug-induced hepatotoxicity is usually associated with the recruitment of immune cells to the liver accelerating an inflammatory response often initiated by activation of the Kupffer cells. In order to evaluate whether the introduction of inflammatory cells could increase the sensitivity for drug-induced cytotoxicity we developed an in vitro co-culture system based on two human cell lines; a hepatoma (Huh-7) and monocytic (THP-1) cell line. As model drugs we chose two peroxisome proliferator activated receptor γ (PPARγ) agonists, the hepatotoxic troglitazone and the non-hepatotoxic rosiglitazone. In the co-cultures, troglitazone caused an enhanced cytotoxicity as compared to single cultures of either cell line, whereas little cytotoxicity was seen after treatment with rosiglitazone. Troglitazone treatment increased gene expression of pro-inflammatory mediators and stress-related genes in both cell types, which in general was more pronounced in co-cultures than in single cell cultures. Based on these results we suggest that co-cultures of human hepatoma cells and monocytes might provide an important in vitro system for better prediction of cytotoxicity mediated by potential hepatotoxins.