The endothelial cell EPO receptor has an intermediate affinity for EPO (≈1 nmol/L), between the affinity of the receptor on erythrocyte precursors (≈200 pmol/L) and the neuronal receptor (≈10 to 20 nmol/L).28 Interestingly, the expression of the EPO receptor increases in pathophysiological conditions such as hypoxia.28 EPO administration in CKD patients5 and in rats29 induces an increase in blood pressure that could be related to direct effects of EPO on vascular function or that could be secondary to an increase in hematocrit. Here, EPO is linked to chronic kidney disease.