Acetaminophen cytotoxicity is ameliorated in a human liver organotypic co-culture model.

Leonard J Nelson,Peter C Hayes,Maria Navarro,Philipp Treskes,Olga Tura-Ceide,Kay Samuel,Steven D Morley,John N Plevris

doi:10.1038/srep17455

Abstract

Organotypic liver culture models for hepatotoxicity studies that mimic in vivo hepatic functionality could help facilitate improved strategies for early safety risk assessment during drug development. Interspecies differences in drug sensitivity and mechanistic profiles, low predictive capacity, and limitations of conventional monocultures of human hepatocytes, with high attrition rates remain major challenges. Herein, we show stable, cell-type specific phenotype/cellular polarity with differentiated functionality in human hepatocyte-like C3A cells (enhanced CYP3A4 activity/albumin synthesis) when in co-culture with human vascular endothelial cells (HUVECs), thus demonstrating biocompatibility and relevance for evaluating drug metabolism and toxicity. In agreement with in vivo studies, acetaminophen (APAP) toxicity was most profound in HUVEC mono-cultures; whilst in C3A:HUVEC co-culture, cells were less susceptible to the toxic effects of APAP, including parameters of oxidative stress and ATP depletion, altered redox homeostasis, and impaired respiration. This resistance to APAP is also observed in a primary human hepatocyte (PHH) based co-culture model, suggesting bidirectional communication/stabilization between different cell types. This simple and easy-to-implement human co-culture model may represent a sustainable and physiologically-relevant alternative cell system to PHHs, complementary to animal testing, for initial hepatotoxicity screening or mechanistic studies of candidate compounds differentially targeting hepatocytes and endothelial cells.

Highlights

This implies that such differences in stability of individual CYP450s in culture could result in an artificial culture phenotype that does not reflect the donor phenotype[4]
C3As and HUVECs mono-cultures were evaluated by phase-contrast imaging in mono- and co-culture in either hepatic (MEME+ ) or endothelial (EGM-2) media
Whilst characteristic epithelial morphology of C3As was retained in both MEME+ and EGM-2 media after 3 days of culture, the characteristic endothelial ‘cobblestone’ morphology of HUVECs was absent in MEME+, but present in EGM-2 medium (Fig. 1A,B)

Summary

Introduction

This implies that such differences in stability of individual CYP450s in culture could result in an artificial culture phenotype that does not reflect the donor phenotype[4]. Given the inherent phenotypic instability of PHHs, alternative co-culture-based systems utilizing hepatocyte-like cells with stromal cell support, may provide more in vivo-like cues providing functional and metabolic stability, recognized as key for correct interpretation of in vitro toxicity data[2]. In principle, such systems may be used as a bridge between animal models and humans as the first step in risk assessment[8]. Studies with model toxicants such as APAP have helped to define the roles that chemical stress and drug bioactivation have in the various biological outcomes that may be triggered by chemically reactive metabolites[8,29]

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