[From oxygen to erythropoietin, as a protagonist of the skin-brain-kidney axis].

Erythropoietin synthesis is one of the essential adaptive responses to a hypoxic environment. In mammals, a renal oxygen sensor capable of stimulating erythropoietic hormone synthesis through a transcriptional factor called HIF (hypoxia-inducible factor) has long been identified. Recent research has demonstrated that cerebral astrocytes and skin keratocytes can also produce erythropoietin as a response to different oxygen concentrations. Therefore, it is possible to hypothesize a skin-brain-kidney link which, through erythropoietin production, modulates the oxygen contribution to tissues. Moreover, the results are not so unambiguous and further research on the pleiotropic effects of erythropoetin would be opportune.