(38) found that germ-free (GF) mice without fecal transplantation had the lowest histological OA severity, while those transplanted with feces from OA patients with metabolic syndrome had the highest histological OA severity, levels of inflammatory biomarkers (IL-1β, IL-6, and MIP-1α), and intestinal mucosal permeability. This evidence concerns the gene IL6 and metabolic syndrome.