3D human nonalcoholic hepatic steatosis and fibrosis models

This study presents a simple and robust three-dimensional human hepatic tissue model to emulate steatotic and fibrotic conditions and provide an in vitro model for drug testing and mechanistic studies. Using a photolithographic biofabrication method with a photomask featuring hexagonal units, liver cells, including a human hepatic cell line (HepG2-C3A) and a human hepatic stellate cell line (LX-2) were embedded in gelatin methacryloyl hydrogel. Hepatic steatosis was induced by supraphysiological concentration of free fatty acids; hepatic fibrosis was induced by transforming growth factor- β 1. Induction of steatosis was confirmed by Oil Red O and BODIPY staining and was inhibited with toyocamycin and obeticholic acid. Induction of fibrosis was confirmed by immunostaining for collagen type I and alpha smooth muscle actin and inhibited by rapamycin and curcumin treatment. This model was further preliminarily validated using primary human hepatocytes in a similar setup. These constructs provide a viable, biologically relevant, and higher throughput model of hepatic steatosis and fibrosis and may facilitate the study of the mechanisms of disease and testing of liver-directed drugs.