[Sodium-glucose co-transporter 2 inhibitors: mechanisms of renal action. Implications for diabetes and heart failure]. / Inibitori del co-trasportatore sodio-glucosio di tipo 2: meccanismi d'azione renale. Le implicazioni nel diabete e nello scompenso cardiaco.

ABSTRACT

The liver is not the exclusive site of glucose production in humans in the post-absorption state. Experimental data showed that the kidney is able of carrying out gluconeogenesis. Renal glucose production accounts for 20% of systemic glucose production. Evidence indicates that the kidney is able to reabsorb glucose from the glomerular filtrate through the sodium-glucose co-transporters (SGLT) 1 and 2 placed under the Bowman's capsule, in the thick portion of the proximal convoluted tubule, preserving this essential energy substrate for the organism. The maximal renal glucose reabsorption capacity (TmG), as well as the threshold for the spillover of glucose in the urine, are higher in diabetics than normal subjects and contribute to the hyperglycemic state in the absence of glycosuria. The administration of SGLT2 inhibitors in diabetics improves the excretion of sodium and glucose, reducing the threshold of glycosuria and TmG. This also restores the sodium concentration in the filtrate that reaches the macula densa (juxtaglomerular apparatus), which signals the appropriate perfusion of the kidney, defusing the secretion of renin and the activation of the neurohormonal axis that leads to the production of angiotensin II.Large clinical trials conducted with SGLT2 inhibitors in subjects with type 2 diabetes mellitus have demonstrated the great ability of this new class of drugs to achieve cardiac and renal benefits. All studies have shown SGLT2 inhibitors reduce the risk of hospitalizations for heart failure and the progression of kidney damage. A part of the favorable mechanisms is mediated by the natriuretic effect that is associated with the glycosuric effect, which reduces the activation of the renin-angiotensin-aldosterone system together with glomerular hyperfiltration.The aim of this review is to expand the knowledge among general cardiologists on the role of SGLT2 and SGLT1 in renal glucose homeostasis in healthy and diabetic subjects in the light of a potent class of drugs counteracting heart failure.