In addition, a high-fat diet and short-chain fatty acids (the metabolites of the gut microbiota) can alter intestinal permeability, which is a characteristic of human T2D.100 Increased permeability exacerbates metabolic endotoxemia, thus triggering immune response and IR through toll-like receptor 4 (TLR4), CD14,101 and G protein-coupled receptor (GPR) 41/43.101. Here, TLR4 is linked to type 2 diabetes mellitus.