Red Blood Cell Function and Disorders of Iron Metabolism

Abstract

The red blood cell, or erythrocyte, is an anucleate biconcave disk, approximately 7 µm in diameter. The principal function of the red blood cell is to exchange carbon dioxide for oxygen while in the pulmonary circulation, exchange that oxygen for carbon dioxide in the peripheral tissue, and carry that carbon dioxide back to the lungs. The physicochemical composition of the red cell is aligned to optimize that function. The state of tissue oxygenation, in turn, regulates the production of red cells. This review covers red blood cell function, iron metabolism, iron deficiency, iron overload, and primary iron overload. Figures show a model of the hemoglobin molecule showing the relative alignment of the α chains and β chains; the normal oxygen-hemoglobin dissociation curve shifted by changes in temperature, pH, and the intracellular concentration of 2,3-diphosphoglycerate; body iron supply and storage; regulation of hepcidin expression and its role in disease; blood smear from a patient with iron deficiency; and mechanisms contributing to iron overload in iron-loading anemias. Tables list laboratory results associated with decreased iron balance, causes of iron deficiency, oral iron replacement therapy, parenteral iron replacement therapy, primary iron overload syndromes, secondary iron overload syndromes, laboratory results associated with increased iron stores, and other rare disorders of iron overload. This review contains 6 figures, 20 tables, and 111 references Keywords: Red blood cell, iron deficiency anemia, iron overload, hemochromatosis, hemoglobin, iron balance