Modeling fatty liver disease and progression with stem cell derived hepatocytes

Metabolic dysfunction-associated steatotic liver disease (MASLD) is one of the most pervasive liver disorders. It can progress to metabolic dysfunction-associated steatohepatitis (MASH), hallmarked by increased inflammation and inclination to permanent liver damage. Given the limited treatment options available to patients, models that recapitulate critical features of disease pathogenesis are needed to improve drug development. Here, a MASLD model was developed by differentiating hepatocyte-like cells (HLCs) from human induced pluripotent stem cells (hiPSCs) in 2D and 3D, in which hepatic aggregates exhibited enhanced functionality. Induced HLCs exposed to free fatty acids led to a steatotic phenotype, partially reducing hepatic function. Biochemical cues released from induced HLCs promoted activation of fibroblasts, resulting in increased inflammatory cytokine secretion and extracellular matrix (ECM) deposition. These findings suggest paracrine signaling from hepatocytes to the surrounding stroma can trigger the progression of MASH and fibrosis. Collectively, our results demonstrate the utility of hiPSC derivatives for modeling liver diseases and reveal how heterotypic interactions can drive disease progression.