REG3G and type 2 diabetes mellitus: Interestingly, gut microbiota from obese individuals with type 2 diabetes induced the ‘leakiest’ gut in the ex-GF mice (i.e. having the highest concentration of circulating FITC–dextran, indicating increased gut permeability) (Fig. 4c), together with the highest levels of antimicrobial peptides, especially Reg3γ, in the intestine (Fig. 4d).