Annals of the New York Academy of Sciences
-
Hepcidin (HAMP) negatively regulates iron absorption, degrading the iron exporter ferroportin at the level of enterocytes and macrophages. We showed that mice with beta-thalassemia intermedia (th3/+) have increased anemia and iron overload. However, their hepcidin expression is relatively low compared to their iron burden. ⋯ These observations suggest that low hepcidin levels are responsible for abnormal iron absorption in thalassemic mice and that down-regulation of Hfe might be involved in the pathway that controls hepcidin synthesis in beta-thalassemia. Therefore, these studies suggest that increasing hepcidin and/or Hfe expression could be a strategy to reduces iron overload in these animals. The goal of this paper is to review recent findings that correlate hepcidin, Hfe, and iron metabolism in beta-thalassemia and to discuss potential novel therapeutic approaches based on these recent discoveries.
-
Ann. N. Y. Acad. Sci. · Aug 2010
ReviewThe challenge of obtaining therapeutic levels of genetically modified hematopoietic stem cells in beta-thalassemia patients.
Hematopoietic stem cells (HSCs) function to provide the individual with a continuing supply of blood cells over many decades. To this end, HSCs have evolved unique mechanisms for self-preservation, including resistance to viral infection. Unfortunately, this characteristic may impede the ability to achieve high levels of gene transfer mediated by HIV-based lentiviral vectors. ⋯ In particular, the study of beta-thalassemia patients that underwent allogeneic stem cell transplantation and developed stable, long-term mixed chimerism suggests that HSC gene transfer levels of greater than 25% will be needed for a robust therapeutic effect in such patients. Available pre-clinical and clinical trial lentiviral gene transfer studies suggest that improvements are needed to achieve this goal. Here, we review what level of gene transfer is needed in the context of varying degrees of beta-globin deficiency, what level is currently achievable, and the areas of research which may be fruitful in improving the likelihood of success for patients with the severest forms of beta-thalassemia.