Erythropoietin attenuates acute kidney dysfunction in murine experimental sepsis by activation of the β-common receptor

The b-common receptor (beta cR) plays a pivotal role in the nonhematopoietic tissue-protective effects of erythropoietin (EPO). Here we determined whether EPO reduces the acute kidney injury (AKI) caused by sepsis and whether this effect is mediated by the beta cR. In young (2 months old) C57BL/6 wildtype and beta cR knockout mice, lipopolysaccharide caused a significant increase in serum urea and creatinine, hence AKI. This AKI was not associated with any overt morphological alterations in the kidney and was attenuated by EPO given 1 h after lipopolysaccharide in wild-type but not in beta cR knockout mice. In the kidneys of endotoxemic wild-type mice, EPO enhanced the phosphorylation of Akt, glycogen synthase kinase-3 beta, and endothelial nitric oxide synthase, and inhibited the activation of nuclear factor-kappa B. All these effects of EPO were lost in beta cR knockout mice. Since sepsis is more severe in older animals or patients, we tested whether EPO was renoprotective in 8-month-old wild-type and beta cR knockout mice that underwent cecal ligation and puncture. These older mice developed AKI at 24 h, which was attenuated by EPO treatment 1 h post cecal ligation and puncture in wild-type mice but not in beta cR knockout mice. Thus, activation of the beta cR by EPO is essential for the observed reduction in AKI in either endotoxemic young mice or older mice with polymicrobial sepsis, and for the activation of well-known signaling pathways by EPO.