Sodium tungstate: Is it a safe option for a chronic disease setting, such as diabetes?

Diabetes is a complex metabolic disorder triggered by the deficient secretion of insulin by pancreatic β cells, the resistance of peripheral tissues to the action of the hormone, or both, and is characterized by chronic hyperglycemia leading to organ damage and failure. Tight glycemic control represents the best therapy to delay or stop progression of diabetes, with many antidiabetic drugs being commercially available nowadays. However, no ideal normoglycemic agent has been developed as yet, and those already available still induce hypoglycemia and/or weight gain as major side effects, worsening glycemic control. In this respect, the inorganic salt sodium tungstate (Na2 WO4 ) has been proven to offer a good antidiabetic alternative in different animal models of diabetes, reducing body weight and normalizing glycemia without causing hypoglycemic episodes. The mechanisms of action mediating the potent antidiabetic actions but also the spectrum of undesirable effects of Na2 WO4 are still poorly understood. In fact, along with its beneficial effects, Na2 WO4 has been consistently reported to be toxic and even carcinogenic. Given that Na2 WO4 is accumulated in the kidneys for elimination, here, we discuss a possible association between long-term Na2 WO4 treatment and a higher risk of renal carcinogenesis in diabetic individuals.