Context-Dependent Pharmacological Effects of Metformin on the Immune System.

Metformin is used for the treatment of type 2 diabetes mellitus and has shown therapeutic effects in preclinical models of other pathologies, such as cancer and autoimmune diseases. The antitumor activity of metformin is due, in part, to immunostimulatory effects. In the context of other pathologies, such as autoimmune or inflammatory diseases, metformin has immunosuppressive effects. There is evidence that the immunostimulatory effects of metformin are indirect. The immunosuppressive effects of metformin in other pathologies appear to be a direct consequence of its action on immune cells. Based on these observations we opine that the pharmacology of metformin is dependent on the pathological context which, to our knowledge, is a novel concept in pharmacology.