Drug-induced liver injury occurs in general after several weeks and is often unpredictable. It is characterized by a large spectrum of lesions that includes steatosis and phospholipidosis. Many drugs such as amiodarone and tetracycline have been reported to cause phospholipidosis and/or steatosis. In this study, acute and chronic hepatic effects of these two drugs were investigated using well-differentiated human hepatoma HepaRG cells. Accumulation of typical lipid droplets, labeled with Oil Red O, was observed in hepatocyte-like HepaRG cells after repeat exposure to either drug. Amiodarone caused the formation of additional intracytoplasmic vesicles that did not stain in all HepaRG cells. At the electron microscopic level, these vesicles appeared as typical lamellar bodies and were associated with an increase of phosphatidylethanolamine and phosphatidylcholine. A dose-dependent induction of triglycerides (TG) was observed after repeat exposure to either amiodarone or tetracycline. Several genes known to be related to lipogenesis were induced after treatment by these two drugs. By contrast, opposite deregulation of some of these genes (FASN, SCD1, and THSRP) was observed in fat HepaRG cells induced by oleic acid overload, supporting the conclusion that different mechanisms were involved in the induction of steatosis by drugs and oleic acid. Moreover, several genes related to lipid droplet formation (ADFP, PLIN4) were up-regulated after exposure to both drugs and oleic acid. Conclusion: Our results show that amiodarone causes phospholipidosis after short-term treatment and, like tetracycline, induces vesicular steatosis after repeat exposure in HepaRG cells. These data represent the first demonstration that drugs can induce vesicular steatosis in vitro and show a direct relationship between TG accumulation and enhanced expression of lipogenic genes. (HEPATOLOGY 2011;53:1895-1905 D rug-induced liver injury occurs infrequently after several weeks or months of treatment and usually requires metabolism of the drug to form reactive metabolites and free radicals. It is challenging to investigate because of its rarity and the lack of experimental models; consequently, its pathogenesis is poorly understood. Drug-induced liver injury encompasses a large spectrum of lesions that include steatosis and phospholipidosis resulting from disruption of lipid homeostasis.Hepatic steatosis results from an accumulation of triglycerides (TG) in hepatocytes. It represents a reversible state of metabolic dysfunction that can possibly progress to inflammatory steatohepatitis, irreversible liver damage, fibrosis, cirrhosis, and even hepatocellular carcinoma. 1,2 Many drugs have been classified as steatogenic. Phospholipidosis is characterized by an excessive intracellular accumulation of phospholipids typified as lamellar bodies. It does not per se constitute frank toxicity, 3 but it is reportedly predictive of drug or metabolite accumulation in several target tissues, and as such may be associated with toxicities. Indeed, accumulated ph...

Thiazolidinediones are a class of Peroxisome Proliferator Activated Receptor γ (PPARγ) agonists that reduce insulin resistance in type 2 diabetic patients. Although no detectable hepatic toxicity has been evidenced in animal studies during preclinical trials, these molecules have nevertheless induced hepatic adverse effects in some treated patients. The mechanism(s) of hepatotoxicity remains equivocal. Several studies have been conducted using PCR analysis and microarray technology to identify possible target genes and here we review the data obtained from various in vivo and in vitro experimental models. Although PPARγ is expressed at a much lower level in liver than in adipose tissue, PPARγ agonists exert various PPARγ-dependent effects in liver in addition to PPARγ-independent effects. Differences in effects are dependent on the choice of agonist and experimental conditions in rodent animal studies and in rodent and human liver cell cultures. These effects are much more pronounced in obese and diabetic liver. Moreover, our own recent studies have shown major interindividual variability in the response of primary human hepatocyte populations to troglitazone treatment, supporting the occurrence of hepatotoxicity in only some individuals.