High-throughput toxicity assessment of chemical mixtures in human hepatic organotypic cultures

Publication Date: 8 May 2018

Orbach, S.M. et al. (2018) High-throughput toxicity testing of chemicals and mixtures in organotypic multi-cellular cultures of primary human hepatic cells Toxicology in Vitro. 51, 83–94. DOI: 10.1016/j.tiv.2018.05.006.

Humans are often exposed to chemical mixtures at unknown concentrations, which can pose serious health risks. However, toxicity testing of chemical mixtures is laborious and costly due to the vast number of possible combinations, therefore most remain untested. Combining organotypic culture models with high-throughput screening (HTS) assays emerges as a rapid, cost-efficient solution for toxicity assessment, simultaneously prioritizing chemicals for further examination.

Orback, S.M., et al. designed multicellular hepatic organotypic culture models (μOCMs) utilizing primary human or rat cells assembled via an automated process in 96-well plates, hence ideal for large-scale toxicity evaluations. Four test chemicals: acetaminophen, ethanol, isoniazid, and perfluorooctanoic acid, were introduced to the μOCMs either individually or as mixtures.

HTS assays were used to measure toxicity indicators such as cell death, apoptosis, glutathione depletion, mitochondrial membrane damage, and cytochrome P450 2E1 activity in the μOCMs. The models displayed increased sensitivity to chemicals in comparison to traditional hepatocyte sandwich cultures, demonstrating a clear advantage of using 3D liver models for toxicity testing. The study unveiled synergistic and non-synergistic interactions when toxicants were mixed. Specifically, chemical interactions in the μOCMs led to changes in apoptosis and decreased glutathione levels. By comparing results from human and rat OCMs, the study also uncovered species-dependent responses, highlighting the importance of using human liver cells to evaluate hepatoxicity.

The findings demonstrate that the μOCMs accurately predicted hepatotoxicity for both individual and mixtures of toxicants, validating their potential for future large-scale toxicity evaluations.

Keywords: high-throughput, hepatotoxicity, organotypic culture models, multi-cellular, chemical mixtures