[Myelodysplastic syndromes and iron metabolism].

Myelodysplastic syndromes (MDS) are clonal hematopoietic disorders characterized by ineffective hematopoiesis in bone marrow and cytopenias in peripheral blood. In patients with MDS, iron overload is frequent due to red blood cell transfusions and ineffective erythropoiesis. Dysplastic erythroblasts in MDS secrete humoral factors such as erythroferrone, which suppress hepatic expression of hepcidin. Hepcidin is the key regulator of systemic iron homeostasis, and suppression of hepcidin expression leads to an increase in iron absorption from the intestines, exacerbating systemic iron overload. Patients with MDS with ring sideroblasts (MDS-RS) are prone to iron overload, with most harboring splicing factor 3B subunit 1 (SF3B1) mutations in hematopoietic cells. SF3B1 mutations may induce ring sideroblasts by downregulating ATP binding cassette subfamily B member 7, which exports iron-sulfur clusters from the mitochondria to the cytoplasm. Iron overload in MDS causes hepatic dysfunction, diabetes, cardiac failure, and atherosclerosis, whereas excess iron may suppress normal hematopoiesis. Though randomized control studies are lacking, results from retrospective and cohort studies indicate that iron chelation therapy is appropriate for lower-risk MSD patients with transfusion-related iron overload, although it is not recommended for higher-risk MSD patients with short life expectancy.