Erythropoiesis

Erythropoietin is a vital hormone that stimulates the bone marrow to create red blood cells in the body. These red blood cells help carry oxygen to other cells and tissues in the body through the bloodstream. Having too much or too little erythropoietin in the body may contribute to problems with the blood. Doctors may therefore recommend tests to check erythropoietin levels in people with blood disorders such as anemia. People with very low levels of erythropoietin may need injections of the hormone. These injections may successfully resolve the issue, but they do carry their own risks. In this article, learn more about erythropoietin, including what it does and who is at risk of deficiency. Share on Pinterest A doctor may order a blood test to check erythropoietin levels. Erythropoietin is a hormone that plays an important role in making red blood cells. The kidneys and liver produce erythropoietin when oxygen levels in the cells are low. The hormone then stimulates the bone marrow, which, in turn, makes more red blood cells. It is normal for a small amount of erythropoietin to circulate in the blood, as this helps replenish the body’s natural blood stores. Having higher levels of erythropoietin in the blood may be a sign that the body is not getting enough oxygen, however. This may be due to a low red blood cell count from anemia or another condition. On the other hand, low levels of erythropoietin in the blood in someone with anemia may be a sign of other issues. Eryth...

Hematopoiesis is blood cell production. Your body continually makes new blood cells to replace old ones. Hematopoiesis ensures you have a healthy supply of blood cells to supply oxygen to your tissue (red blood cells), fight infection (white blood cells) and clot your blood when you’re injured (platelets). Most blood cells get made in your bone marrow. What is hematopoiesis? Hematopoiesis (pronounced “heh-ma-tuh-poy-EE-sus”) is blood cell production. Your body continually makes new blood cells to replace old blood cells so you have a steady blood supply. Hematopoiesis starts before birth and continues as a cycle throughout life. It’s easier to remember what hematopoiesis is when you consider its roots. Hematopoiesis is derived from two Greek words: • Haîma: Blood. • Poiēsis: To make something. Put these words together, and you get hematopoiesis, the process of making blood. Hematopoiesis is also called hemopoiesis, hematogenesis and hemogenesis. What blood cells get made during hematopoiesis? Your blood cells are the building blocks of your blood. Hematopoiesis includes the production of all blood cell types, including: Red blood cells (erythrocytes) White blood cells (leukocytes) Broadly, the types of white blood cells are: • • • • • Neutrophils, basophils and eosinophils have similar functions and can be grouped together and called Platelets (thrombocytes) Where does hematopoiesis occur? The most common site of blood cell production is the spongy tissue inside of your bo...

The erythroid marrow and circulating red blood cells (RBCs) are the key components of the human erythron. Abnormalities of the erythron that are responsible for anemia can be separated into 3 major categories: erythroid hypoproliferation, ineffective erythropoiesis, and peripheral hemolysis. Ineffective erythropoiesis is characterized by erythropoietin-driven expansion of early-stage erythroid precursors, associated with apoptosis of late-stage precursors. This mechanism is primarily responsible for anemia in inherited disorders like β-thalassemia, inherited sideroblastic anemias, and congenital dyserythropoietic anemias, as well as in acquired conditions like some subtypes of myelodysplastic syndrome (MDS). The inherited anemias that are due to ineffective erythropoiesis are also defined as iron-loading anemias because of the associated parenchymal iron loading caused by the release of erythroid factors that suppress hepcidin production. Novel treatments specifically targeting ineffective erythropoiesis are being developed. Iron restriction through enhancement of hepcidin activity or inhibition of ferroportin function has been shown to reduce ineffective erythropoiesis in murine models of β-thalassemia. Luspatercept is a transforming growth factor-β ligand trap that inhibits SMAD2/3 signaling. Based on preclinical and clinical studies, this compound is now approved for the treatment of anemia in adult patients with β-thalassemia who require regular RBC transfusions. Luspa...

Anemia, a decrease in the number of red blood cells (RBCs), hemoglobin (Hb) content, or hematocrit (Hct), can result from decreased Red Blood Cell Production Red blood cell (RBC) production (erythropoiesis) takes place in the bone marrow under the control of the hormone erythropoietin (EPO). Juxtaglomerular cells in the kidney produce erythropoietin... read more (erythropoiesis), increased RBC destruction, blood loss, or a combination of these factors. (See also Evaluation of Anemia Anemia is a decrease in the number of red blood cells (RBCs) as measured by the red cell count, the hematocrit, or the red cell hemoglobin content. In men, anemia is defined as any of the following... read more .) The Testing Anemia is a decrease in the number of red blood cells (RBCs) as measured by the red cell count, the hematocrit, or the red cell hemoglobin content. In men, anemia is defined as any of the following... read more , mainly the mean corpuscular volume (MCV), can narrow the differential diagnosis of deficient erythropoiesis and help determine what further testing is necessary. Iron-utilization anemias (including some Sideroblastic Anemias Sideroblastic anemias are a diverse group of anemias characterized by the presence of increased serum iron, ferritin, and transferrin saturation as well as ringed sideroblasts (erythroblasts... read more and Lead Poisoning Lead poisoning often causes minimal symptoms at first but can cause acute encephalopathy or irreversible organ damage, com...

Red blood cell (RBC) production (erythropoiesis) takes place in the bone marrow under the control of the hormone erythropoietin (EPO). Juxtaglomerular cells in the kidney produce erythropoietin in response to decreased oxygen delivery (as in anemia or hypoxia) or increased levels of androgens. In addition to erythropoietin, red blood cell production requires adequate supplies of substrates, mainly Iron Deficiency Iron (Fe) is a component of hemoglobin, myoglobin, and many enzymes in the body. Heme iron is contained mainly in animal products. It is absorbed much better than nonheme iron (eg, in plants... read more , Vitamin B12 Deficiency Dietary vitamin B12 deficiency usually results from inadequate absorption, but deficiency can develop in vegans who do not take vitamin supplements. Deficiency causes megaloblastic anemia, damage... read more , Folate Deficiency Folate deficiency is common. It may result from inadequate intake, malabsorption, or use of various drugs. Deficiency causes megaloblastic anemia (indistinguishable from that due to vitamin... read more , and Overview of Porphyrias Porphyrias are rare disorders in which there are defects in the pathway of heme synthesis due to genetic or acquired deficiencies of enzymes of the heme biosynthetic pathway. These deficiencies... read more . RBCs survive about 120 days. They then lose their cell membranes and are largely cleared from the circulation by the phagocytic cells of the spleen and liver. Hemoglobin is broken d...