GIP and type 2 diabetes mellitus: Furthermore, two key factors collectively amplify metabolic stress: first, impaired intestinal insulin secretion in T2DM—manifested as blunted glucose-dependent insulinotropic polypeptide (GIP) responsiveness and reduced GLP-1 levels [26]—and, second, bidirectional crosstalk between “microbiota–metabolism–renal injury” induced by gut microbiota dysbiosis in DKD [27,28,29].