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In vitro to in vivo extrapolation and high-content imaging for simultaneous characterization of chemically induced liver steatosis and markers of hepatotoxicity
Citation:
Muller, F., M. Stamou, F. Englert, O. Frenzel, S. Diedrich, L. Suter-Dick, J. Wambaugh, AND S. Sturla. In vitro to in vivo extrapolation and high-content imaging for simultaneous characterization of chemically induced liver steatosis and markers of hepatotoxicity. Archives of Toxicology. Springer, New York, NY, 97(6):1701-1721, (2023). https://doi.org/10.1007/s00204-023-03490-8
Impact/Purpose:
Nonalcoholic fatty liver disease (NAFLD) affects around 25% of the adult population and 70-80% of obese or diabetic. It is a complex spectrum of diseases ranging from benign liver steatosis to non-alcoholic steatohepatitis (NASH). Steatosis is a hepatic accumulation of fatty acids such that the total liver fat content exceeds 5%. Although steatosis is considered benign, in the presence of persistent inflammation it can progress to NASH, with significant hepatocyte injury and often irreversible progression. Exposure to environmental chemicals, such as solvents, persistent organic pollutants, and pesticides, has been implicated as a risk factor. Findings from epidemiological studies suggest a link between exposure to heavy metals (lead, mercury) and polychlorinated biphenyls (PCBs) and NAFLD prevalence. In addition, the prevalence of NAFLD and its link to obesity and metabolic disorders suggest that food-related exposures could contribute to NAFLD risk, but these have not been systematically assessed. Thus, an important task for hazard characterization and safety management is to predict which chemicals may increase susceptibility to NAFLD.
Description:
Chemically induced steatosis is characterized by lipid accumulation associated with mitochondrial dysfunction, oxidative stress and nucleus distortion. New approach methods integrating in vitro and in silico models are needed to identify chemicals that may induce these cellular events as potential risk factors for steatosis and associated hepatotoxicity. In this study we used high-content imaging for the simultaneous quantification of four cellular markers as sentinels for hepatotoxicity and steatosis in chemically exposed human liver cells in vitro. Furthermore, we evaluated the results with a computational model for the extrapolation of human oral equivalent doses (OED). First, we tested 16 reference chemicals with known capacities to induce cellular alterations in nuclear morphology, lipid accumulation, mitochondrial membrane potential and oxidative stress. Then, using physiologically based pharmacokinetic modeling and reverse dosimetry, OEDs were extrapolated from data of any stimulated individual sentinel response. The extrapolated OEDs were confirmed to be within biologically relevant exposure ranges for the reference chemicals. Next, we tested 14 chemicals found in food, selected from thousands of putative chemicals on the basis of structure-based prediction for nuclear receptor activation. Amongst these, orotic acid had an extrapolated OED overlapping with realistic exposure ranges. Thus, we were able to characterize known steatosis-inducing chemicals as well as data-scarce food-related chemicals, amongst which we confirmed orotic acid to induce hepatotoxicity. This strategy addresses needs of next generation risk assessment and can be used as a first chemical prioritization hazard screening step in a tiered approach to identify chemical risk factors for steatosis and hepatotoxicity-associated events.
URLs/Downloads:
DOI: In vitro to in vivo extrapolation and high-content imaging for simultaneous characterization of chemically induced liver steatosis and markers of hepatotoxicity
https://pubmed.ncbi.nlm.nih.gov/37046073/