AQP2 and type 2 diabetes mellitus: In parallel with this finding, the current study has inferred that the expression level of AQP2, gatekeeper of water permeability, and FOXP3, a key player for the development and function of Treg (regulatory T cell), were drastically declined in T2D + CHD group around 57 and 170 times, respectively, compared to the patients in T2D group.