Beta-thalassemia intermedia (TI) is associated with a variety of serious clinical complications that require proactive and comprehensive management. These include skeletal deformities and osteopenia, compensatory extramedullary hematopoiesis and tumor formation, progressive splenomegaly, a hypercoagulable state resulting in thromboembolic events and pulmonary hypertension, and increased gastrointestinal iron absorption that often results in nontransfusional iron overload and liver damage. Although TI is generally considered a non-transfusion-dependent thalassemia, transfusion therapy may be an important part of the comprehensive management of this disease. This review describes the current state of the art for medical management of TI, with particular focus on the roles of splenectomy, transfusion, and iron chelation therapy.
[Show abstract][Hide abstract] ABSTRACT: Recent molecular studies of fetal hemoglobin (HbF) regulation have reinvigorated the field and shown promise for the development of clinical HbF inducers to be used in patients with β-thalassemia and sickle cell disease. However, while numerous promising inducers of HbF have been studied in the past in β-thalassemia patient populations, with limited success in some cases, no universally effective agents have been found. Here we examine the clinical studies of such inducers in an attempt to systematically review the field. We examine trials of agents including 5-azacytidine, hydroxyurea, short-chain fatty acids, and others in this review. This review highlights the heterogeneity of clinical studies done on these agents, including both the patient populations examined and the study end points. By examining the published studies of these agents, we hope to provide a resource that will be valuable for the design of future studies of HbF inducers in β-thalassemia patient populations.
[Show abstract][Hide abstract] ABSTRACT: β-Thalassemia and HFE-related hemochromatosis are 2 of the most frequently inherited disorders worldwide. Both disorders are characterized by low levels of hepcidin (HAMP), the hormone that regulates iron absorption. As a consequence, patients affected by these disorders exhibit iron overload, which is the main cause of morbidity and mortality. HAMP expression is controlled by activation of the SMAD1,5,8/SMAD4 complex. TMPRSS6 is a serine protease that reduces SMAD activation and blocks HAMP expression. We identified second generation antisense oligonucleotides (ASOs) targeting mouse Tmprss6. ASO treatment in mice affected by hemochromatosis (Hfe-/-) significantly decreased serum iron, transferrin saturation and liver iron accumulation. Furthermore, ASO treatment of mice affected by β-thalassemia (HBBth3/+ mice, referred to hereafter as th3/+ mice) decreased the formation of insoluble membrane-bound globins, ROS, and apoptosis, and improved anemia. These animals also exhibited lower erythropoietin levels, a significant amelioration of ineffective erythropoiesis (IE) and splenomegaly, and an increase in total hemoglobin levels. These data suggest that ASOs targeting Tmprss6 could be beneficial in individuals with hemochromatosis, β-thalassemia, and related disorders.
The Journal of clinical investigation 03/2013; 123(4). DOI:10.1172/JCI66969 · 13.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Non-transfusion-dependent thalassemias include a variety of phenotypes that, unlike patients with beta (β)-thalassemia major, do not require regular transfusion therapy for survival. The most commonly investigated forms are β-thalassemia intermedia, hemoglobin E/β-thalassemia, and α-thalassemia intermedia (hemoglobin H disease). However, transfusion-independence in such patients is not without side effects. Ineffective erythropoiesis and peripheral hemolysis, the hallmarks of disease process, lead to a variety of subsequent pathophysiologies including iron overload and hypercoagulability that ultimately lead to a number of serious clinical morbidities. Thus, prompt and accurate diagnosis of non-transfusion-dependent thalassemia is essential to ensure early intervention. Although several management options are currently available, the need to develop more novel therapeutics is justified by recent advances in our understanding of the mechanisms of disease. Such efforts require wide international collaboration, especially since non-transfusion-dependent thalassemias are no longer bound to low- and middle-income countries but have spread to large multiethnic cities in Europe and the Americas due to continued migration.
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