GDF15 and metabolic dysfunction-associated steatohepatitis: Consistent with a previous report that GDF15 expression was detected only in parenchymal cells but not in non-parenchymal cells in the liver5, Gdf15 expression was increased only in a hepatocyte cell line but not in a hepatic stellate cell (HSC) line or a Kupffer cell line after exposure to MCD media in an in vitro model of NASH (Fig. 1d), suggesting that increased GDF15 expression in hepatocytes might contribute to the increases of hepatic Gdf15 expression and serum GDF15 level in MCD diet-induced NASH.