MASLD-Induced Liver Micro-Organoids Mimics Clinical Observations of Impaired Vitamin D Synthesis

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global health concern associated with various metabolic disorders and a high prevalence of vitamin D deficiency. Current animal models face limitations in accurately mimicking human metabolic pathways and are constrained by ethical considerations. This study aimed to develop an in vitro MASLD-induced liver micro-organoid model to investigate the impact of MASLD on vitamin D metabolism. The model incorporates HepaRG cells as hepatocytes, LX-2 cells as stellate cells, and human umbilical vein endothelial cells (HUVECs). Fatty liver characteristics were induced by treating the micro-organoids with palmitic/oleic acids. fatty acid accumulation was quantified and visualized using Bodipy staining. The expression of genes involved in drug and vitamin D metabolism was evaluated by RT-PCR. Dot blot analysis assessed secreted proteins indicative of liver damage. ELISA was used to examine vitamin D metabolism. The results confirmed the successful induction of MASLD, evidenced by altered cytochrome P450 gene expression, elevated markers of liver damage, and reduced vitamin D metabolism. These findings align with clinical studies and RNA-sequencing data from liver biopsies of MASLD patients. This innovative micro-organoid platform offers a robust tool for studying the molecular mechanisms of MASLD and represents a promising alternative to animal experiments.