Species-specific differences in coumarin-induced hepatotoxicity as an example toxicogenomics-based approach to assessing risk of toxicity to humans

Abstract

<jats:p> One expected result from toxicogenomics technology is to overcome the barrier because of species-specific differences in prediction of clinical toxicity using animals. The present study serves as a model case to test if the well-known species-specific difference in the toxicity of coumarin could be elucidated using comprehensive gene expression data from rat in-vivo, rat in-vitro, and human in-vitro systems. Coumarin 150 mg/kg produced obvious pathological changes in the liver of rats after repeated administration for 7 days or more. Moreover, 24 h after a single dose, we observed minor and transient morphological changes, suggesting that some early events leading to hepatic injury occur soon after coumarin is administered to rats. Comprehensive gene expression changes were analyzed using an Affymetrix GeneChip<jats:sup>®</jats:sup> approach, and differentially expressed probe sets were statistically extracted. The changes in expression of the selected probe sets were further examined in primary cultured rat hepatocytes exposed to coumarin, and differentially expressed probe sets common to the in-vivo and in-vitro datasets were selected for further study. These contained many genes related to glutathione metabolism and the oxidative stress response. To incorporate human data, human hepatocyte cultured cells were exposed to coumarin and changes in expression of the bridging gene set were examined. In total, we identified 14 up-regulated and 11 down-regulated probe sets representing rat–human bridging genes. The overall responsiveness of these genes to coumarin was much higher in rats than humans, consistent with the reported species difference in coumarin toxicity. Next, we examined changes in expression of the rat–human bridging genes in cultured rat and human hepatocytes treated with another hepatotoxicant, diclofenac sodium, for which hepatotoxicity does not differ between the species. Both rat and human hepatocytes responded to the marker genes to the same extent when the same concentrations of diclofenac sodium were exposed. We conclude that toxicogenomics-based approaches show promise for overcoming species-specific differences that create a bottleneck in analysis of the toxicity of potential therapeutic treatments. </jats:p>

Toxicogenomics discrimination of potential hepatocarcinogenicity of non‐genotoxic compounds in rat liver

“…Microarray analysis was conducted on three out of five samples for each group using RG230 2.0 probe arrays (Affymetrix). The procedure was performed according to the manufacturer's protocol as previously reported (Uehara et al ., , ) and the obtained image files were analyzed with the Affymetrix data suite system, Microarray Suite 5.0 (MAS 5.0). The derived signal values were globally normalized and targeted to all probe sets equal to 500 before comparative analysis to examine gene expression differences between treatment and control samples.…”

Tissue Engineering Approaches in the Design of Healthy and Pathological In Vitro Tissue Models

“…However, the capability to maintain liver native functions for only few days (about three days) under conventional cell culture conditions, together with tissue shortage and its high variability, have limited the establishment of 2D primary hepatocyte cell culture and consequently the use of these cells in the development of liver models (Guillouzo and Guguen-Guillouzo, 2008; Mazzoleni and Steimberg, 2012; Mueller et al, 2013; Soldatow et al, 2013). Primary rodent hepatocytes have been widely exploited in drug testing and drug-drug interaction studies, but the translation of the obtained results to humans is made difficult by differences in metabolism among the two species (Uehara et al, 2008; Lauer et al, 2009). On the other hand, human immortalized hepatic cancer cell lines, such as HepG2, show unlimited availability and maintain certain liver functions, e.g., albumin production (Mueller et al, 2013).…”

State-of-the-art of 3D cultures (organs-on-a-chip) in safety testing and pathophysiology

“…However, species-specific differences in xenobiotic metabolism necessitate the use of human hepatocytes in preclinical pharmaceutical development (Hewitt et al, 2001;lauer et al, 2009;Uehara et al, 2008). In particular, human cells most faithfully replicate actual human pharmaco-(and toxico-) kinetics and drug (chemical) metabolism.…”