Advanced In Vitro HepaRG Culture Systems for Xenobiotic Metabolism and Toxicity Characterization.

Several HepaRG three-dimensional (3D) in vitro model systems have been developed to improve the predictability of xenobiotic metabolism and toxicity. In this review, we present a detailed summary and critique of the performance of various HepaRG 3D models compared to the conventional 2D monolayer culture. HepaRG 3D models can be broadly categorized into (1) scaffold-free, (2) scaffold-based, and (3) bioartificial liver (BAL) models. With respect to the scaffold-free configurations, the hanging drop model closely mimics the normal physiological function and metabolic profile of the liver. The micromold model is suitable for high-throughput multiplexed assays and exhibits higher accuracy when predicting drug-induced liver toxicity risk in both acute and chronic culture. Scaffold- and BAL-based models also present improved precision and accuracy for hepatotoxic drug screening in addition to allowing improved model control to closely mimic physiological assay conditions. Overall, all 3D HepaRG models exhibit improved cellular function, metabolic activity, and toxicity screening ability compared to the conventional 2D monolayer culture. These improvements reported in 3D models may be due to a higher degree of differentiation and cell polarity. Nevertheless, the expression and functions of various phase II, phase III, and nuclear receptors need to be further characterized in these 3D models.