Erythropoiesis is the process by which red blood cells (erythrocytes) are produced. The bone marrow, specifically the erythropoietic stem cells, is the primary site of this process. Once mature red blood cells are formed, they are released into the bloodstream, where they are responsible for transporting oxygen throughout the body.
The production of red blood cells is regulated by a hormone called erythropoietin (EPO). This hormone is primarily produced by the peritubular cells of the renal cortex in response to low oxygen levels in the blood.
Here's a simplified breakdown of the erythropoiesis process:
- Stimulation: The kidneys detect low oxygen levels in the blood and release EPO.
- Development: EPO stimulates the erythropoietic stem cells in the bone marrow to differentiate into red blood cells.
- Maturation: The developing red blood cells go through several stages of maturation, losing their nucleus and gaining their characteristic biconcave shape.
- Release: Once fully mature, the red blood cells are released into the bloodstream.
Problems with erythropoiesis can lead to various health issues, including anemia. Anemia is a condition characterized by a low number of red blood cells or a deficiency in hemoglobin, the protein responsible for oxygen transport. Erythropoiesis-stimulating agents (ESAs) are medications used to treat anemia by stimulating the production of red blood cells.
Examples of ESAs include:
- Epoetin alfa (marketed as Procrit and Epogen)
- Darbepoetin alfa (marketed as Aranesp)
