CCL2 and fatty liver disease: Germ-free animals transplanted with fecal from NAFLD patients demonstrated significant hepatic steatosis, multifocal necrosis, and inflammatory cell infiltration in the liver, accompanied by increased levels of serum LPS and inflammatory cytokines (such as IL-6 and MCP-1) and the disturbance of intestinal flora, indicating that the occurrence of NAFLD is closely related to intestinal flora disturbance (Chiu et al., 2017).