Erythropoietin treatment leads to reduced blood glucose levels and body mass: insights from murine models.

Erythropoietin (EPO) regulates proliferation and differentiation of erythroid precursor cells into erythrocytes. The last decade has revealed non-renal sites of EPO production and extrahematopoietic expression of the EPO receptor, thus suggesting that EPO has pleiotropic functions. Here, we addressed the interplay between EPO/glucose metabolism/body weight by employing a panel of relevant experimental murine models. The models focused on situations of increased EPO levels, including EPO-injected C57BL/6 and BALB/c mice, as well as transgenic mice (tg6) constitutively overexpressing human EPO, thus exposed to constantly high EPO serum levels. As experimental models for diabetes and obesity, we employed protein Tyr phosphatase 1B (PTP1B) knockout mice associated with resistance to diabetes (PTP1B(-/-)), and ob/ob mice susceptible to diabetes and obesity. The data presented herein demonstrate EPO-mediated decrease in blood glucose levels in all mice models tested. Moreover, in the ob/ob mice, we observed EPO-mediated attenuation of body weight gain and reduction of hemoglobin A1c. Taken together, our data bear significant clinical implications of EPO treatment in the management of a wide range of metabolic diseases, thus adding an important novel therapeutic potential to this pleiotropic hormone.