Erythropoietin and the nervous system.

Erythropoietin (Epo) is a hematopoietic growth factor and cytokine which stimulates erythropoiesis. In recent years, Epo has been shown to have important nonhematopoietic functions in the nervous system. Nonerythropoietic actions of Epo include a critical role in the development, maintenance, protection and repair of the nervous system. A wide variety of experimental studies have shown that Epo and its receptor are expressed in the nervous system and Epo exerts remarkable neuroprotection in cell culture and animal models of nervous system disorders. In this review, we summarize the current knowledge on the neurotrophic and neuroprotective properties of Epo, the mechanisms by which Epo produces neuroprotection and the signal transduction systems regulated by Epo in the nervous system.