The discovery of erythropoietin (ePO) in the mid-1950s heralded a new era in clinical medicine. The substance responsible for hematopoiesis in response to hypoxia was no longer a mystery and the subsequent growth in recombinant technology enabled the commercial use of ePO as therapy for some patients with anemia. Erythropoietin is a glycoprotein produced predominantly by the juxtaglomerular apparatus of the kidneys and released in response to hypoxia. The normal concentration in human plasma is between 8 and 18 mU/ml. The mechanism by which ePO enhances erythropoiesis is unknown, but likely involves the prevention of apoptosis among erythroid progenitor cells in the bone marrow [1].

The last decade has seen a number of new clinical applications of recombinant ePO [2], including autonomic neuropathy of various causes [3–6]. In this issue of Clinical Autonomic Research, Winkler and colleagues describe the therapeutic effects of ePO in a patient with multiple system atrophy. What is the link between anemia and orthostatic hypotension and why does ePO seem to work?