Delivery of iron to K562 cells by diferric transferrin involves a cycle of binding to surface receptors, internalization into an acidic compartment, transfer of iron to ferritin, and release of apotransferrin from the cell. To evaluate potential feedback effects of iron on this system, we exposed cells to iron chelators and monitored the activity of the transferrin receptor. In the present stud...

Iron chelation therapy using iron (III) specific chelators such as desferrioxamine (DFO, Desferal), deferasirox (Exjade or ICL-670), and deferiprone (Ferriprox or L1) are the current standard of care for the treatment of iron overload. Although each chelator is capable of promoting some degree of iron excretion, these chelators are also associated with a wide range of well documented toxicities...

OBJECTIVE Major thalassemia is one of the hematological diseases requiring multiple blood transfusions, which results in iron overload in the liver, heart and other organs. Current iron chelation therapy consists of intravenous (IV) deferoxamine and oral deferasirox and deferiprone. Although these chelators are effective, many side effects are reported. In the present study, the iron-chelating ...

The relationship between the oral efficacy and the acute toxicity of hydroxypyridin-4-one iron chelators has been investigated to clarify structure-function relationships of these compounds in vivo and to identify compounds with the maximum therapeutic safety margin. By comparing 59Fe excretion following oral or intraperitoneal administration of increasing doses of each chelator to iron-overloa...

Deferitrin (GT-56-252) is the first drug in a class of desferrithiocin-derived hexadentate iron chelators. Genzyme Corp is developing this compound as an oral drug for the treatment of severe iron overload in people who require repeated erythrocyte transfusion for management of chronic anemia such as beta-thalassemia major. In phase I trials in adults with beta-thalassemia, deferitrin promoted ...

The pharmacokinetic behavior of three iron chelators based on the desferrithiocin (DFT) pharmacophore, (S)-4, 5-dihydro-2-(2-hydroxyphenyl)-4-thiazolecarboxylic acid (desmethyldesferrithiocin, DMDFT, 2); (S)-4,5-dihydro-2-(2, 4-dihydroxyphenyl)-4-thiazolecarboxylic acid [4-(S)-hydroxydesazaDMDFT, 3); and (R)-2-(2-hydroxyphenyl)-4-oxazolinecarboxylic acid, the oxazoline analog of desazaDMDFT, 4,...

The mechanism of in vivo iron chelation by 3-hydroxypyridin-4-ones (CP compounds) was studied in hypertransfused rats in which the major storage iron pools in hepatocytes and in the reticuloendothelial (RE) system have been labeled by selective radioiron probes. Both dimethyl-3-hydroxypyridin-4-one (CP 20 or L1) and diethyl-3-hydroxypyridine-4-one (CP 94) have an identical and very high (log be...

Transfusion and iron chelation therapy revolutionised survival and reduced morbidity in patients with transfusion-dependent beta thalassaemia major. Despite these improvements, cardiac disease remained the most common cause of death in those patients. Recently the ability to determine the degree of cardiac iron overload, through cardiac magnetic resonance imaging (CMR) has allowed more logical ...

Red blood cells (RBCs) from patients with sickle cell anemia and thalassemia carry abnormal accumulations of molecular Fe(III) at the cytosol/membrane interface. The avidity of the red cell membrane for this iron has not been defined. Using open ghost membranes prepared from sickle RBC, we examined the ability of membrane-associated Fe(III) to resist removal by 15 chelators representing a 40-lo...

Recent developments in the understanding of the molecular control of iron homeostasis provided novel insights into the mechanisms responsible for normal iron balance. However in chronic anemias associated with iron overload, such mechanisms are no longer sufficient to offer protection from iron toxicity, and iron chelating therapy is the only method available for preventing early death caused m...