Recapitulation of clinical and molecular hallmarks of lipid-induced hepatic insulin resistance in a zonated, vascularized human liver acinus microphysiological system during metabolic dysfunction-associated steatotic liver disease (MASLD) progression.

Metabolic dysfunction-associated steatotic liver disease (MASLD) impacts ca. 30% of the global population and is very heterogeneous, making it a challenge to develop therapeutics. The heterogeneity arises from genetics, co-morbidities, the microbiome, and lifestyle. To help address this challenge, we have refined the human vascularized liver acinus microphysiological system (vLAMPS), which provides an all-human platform for drug development, satisfying recently updated federal requirements for the use of New Approach Methodologies (NAMs). By introducing clinically relevant media perturbations and employing several diverse and reproducible in situ and systemic measurements, we show that the vLAMPS can recapitulate key structural and functional aspects of normal physiology, acinus zonation, and all stages of MASLD progression including stellate cell activation and fibrosis. Importantly, in this study we also demonstrate that several hallmarks of lipid-induced hepatic insulin resistance paralleled MASLD progression. These included reduction of insulin receptor substrate 2 (IRS2) protein, compromised insulin receptor mediated insulin clearance, enhanced pericentral lipid accumulation, increased Very-low-density lipoprotein (VLDL) secretion, and enhanced hepatic glucose output mediated by increased periportal nuclear translocation of Forkhead box protein O1 (FOXO1). These results suggest that the mechanisms underlying MASLD progression in vLAMPS are clinically relevant and support the tenable hypothesis that the hepatic insulin resistant state plays both a causal and consequential role in a vicious cycle driving disease progression.