The diabetic kidney presents excess expression and activity of the SGLT2 transporter of the proximal tubule. This situation increases the renal reabsorption of Na and glucose and reduces their distal supply. In addition to the metabolic effects on the internal environment of this excess reabsorbed glucose, the renal tubule is subjected to glycosylated stress capable of locally activating both apoptosis and inflammasome. The result is a progressive loss of nephron units, activation of transition of mesangial epithelium and collagen deposition. Activation of insulin signalling by the MAP kinase pathway and resistance to the metabolic effects of insulin take place. This is simultaneously combined with afferent vasodilation due to hyperglycaemia, tubuloglomerular feedback inhibition due to reduced distal fluid supply, podocyte dedifferentiation and reduction in their number, the latter effects being due to insulin resistance. The result is self-feeding renal damage, with intraglomerular hyper-pressure, podocyte dedifferentiation, tubular apoptosis, and local and distant activation of inflammasome. All these effects are susceptible to be totally or partially corrected by inhibiting glucose transport via the SGLT transporters.
