TGFB1 and fibrosis: The finding that Kupffer cells are stimulated to produce TGF-β, which activates hepatic stellate cells, fibrocytes, and mesenchymal stem cells into myofibroblasts, highlights another aspect, about which researchers are still debating, i.e., could fibrosis alone make simple fatty liver progress towards a more severe form (i.e., advanced fibrosis/liver cirrhosis) without the mediation of inflammation?