eritropoetin

Eritropoetin, commonly called erythropoietin in English, is a glycoprotein hormone that stimulates the production of red blood cells. In humans, it is mainly produced by interstitial fibroblasts in the kidneys, and to a lesser extent by the liver, in response to tissue hypoxia. Its synthesis is regulated by hypoxia-inducible factors, particularly HIF-2α. Circulating erythropoietin binds to the erythropoietin receptor (EPOR) on erythroid progenitor cells in the bone marrow, triggering signaling cascades such as JAK2/STAT5, PI3K/AKT, and Ras/MAPK that promote proliferation, differentiation, and survival, increasing red blood cell mass.

Endogenous EPO helps maintain normal red cell mass; exogenous recombinant forms are used to treat anemia. Clinical uses include anemia of chronic kidney disease, anemia associated with cancer chemotherapy, and certain other chronic diseases. In these applications, longer-lasting forms like darbepoetin alfa are used to reduce the frequency of administration. EPO is also used to minimize transfusions in perioperative settings, under careful dosing and monitoring.

Safety and cautions: Overcorrection of hemoglobin raises the risk of thrombosis and hypertension; high-dose treatment can be associated with adverse cardiovascular events and, rarely, the development of neutralizing antibodies that cause pure red cell aplasia. Treatment requires monitoring of hemoglobin levels and iron status, as iron deficiency can limit response.

History: The endogenous hormone was identified in the 20th century, and recombinant forms became available in the 1980s and 1990s, expanding therapeutic options for anemia.