Modeling Nonalcoholic Fatty Liver Disease in the Dish Using Human-Specific Platforms: Strategies and Limitations

Abstract

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease affecting multiple cell types of the human liver. The high prevalence of NAFLD and the lack of approved therapies increase the demand for reliable models for the preclinical discovery of drug targets. In the last decade, multiple proof-of-principle studies have demonstrated human-specific NAFLD modeling in the dish. These systems have included technologies based on human induced pluripotent stem cell derivatives, liver tissue section cultures, intrahepatic cholangiocyte organoids, and liver-on-a-chip. These platforms differ in functional maturity, multicellularity, scalability, and spatial organization. Identifying an appropriate model for a specific NAFLD-related research question is challenging. Therefore, we review different platforms for their strengths and limitations in modeling NAFLD. To define the fidelity of the current human in vitro NAFLD models in depth, we define disease hallmarks within the NAFLD spectrum that range from steatosis to severe fibroinflammatory tissue injury. We discuss how the most common methods are efficacious in modeling genetic contributions and aspects of the early NAFLD-related tissue response. We also highlight the shortcoming of current models to recapitulate the complexity of inter-organ crosstalk and the chronic process of liver fibrosis-to-cirrhosis that usually takes decades in patients. Importantly, we provide methodological overviews and discuss implementation hurdles (eg, reproducibility or costs) to help choose the most appropriate NAFLD model for the individual research focus: hepatocyte injury, ductular reaction, cellular crosstalk, or other applications. In sum, we highlight current strategies and deficiencies to model NAFLD in the dish and propose a framework for the next generation of human-specific investigations.

Keywords: Induced Pluripotent Stem Cells; Liver Organoids; Liver-on-Chip; Precision-Cut Liver Slices.

Figure 1

Experimental milestones and time considerations in NAFLD models. Each model includes sequential steps of sample preparation before experimentation. hiPSC, human induced pluripotent stem cell. Created with biorender.com.

Figure 2

Technical considerations and NAFLD hallmark fidelity of NAFLD models. This figure depicts the NAFLD models discussed in this review in relation to either their relevance for the study of typical NAFLD hallmarks or material needs. ER, endoplasmic reticulum; hiPSC, human induced pluripotent stem cell; ICO, intrahepatic cholangiocyte organoid; NAFLD, nonalcoholic fatty liver disease. Created with biorender.com.