Some pathological conditions give rise to gut microbiota perturbations (referred to as dysbiosis) and a subsequent impairment of intestinal barrier function (due to disorganized tight junction proteins, zonulin and occludin, in colonocytes); in these circumstances, microbial metabolites can cross the intestinal barrier and move to the bloodstream, triggering systemic pro-inflammatory signaling that, in turn, causes metabolic alterations (peripheral insulin resistance, hyperglycemia and non-alcoholic fatty liver disease (NAFLD)) in distant tissues [11,53]. The gene discussed is INS; the disease is metabolic dysfunction-associated steatotic liver disease.