Macrophages closely approximate with collagen-producing HSCs [163] and can directly activate stellate cells via the release of IL-6 and TGFβ [157,164], although a number of potential macrophage-derived factors have been described whose expression correlates with NASH severity or HSC activation (e.g., chitotriosidase) [22,165,166]. The gene discussed is TGFB1; the disease is metabolic dysfunction-associated steatohepatitis.