Research ArticleBlood Disorders

Thrombopoietin receptor–independent stimulation of hematopoietic stem cells by eltrombopag

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Science Translational Medicine  12 Sep 2018:
Vol. 10, Issue 458, eaas9563
DOI: 10.1126/scitranslmed.aas9563

Ironing out bone marrow failure

Chronic thrombocytopenia can be associated with a variety of conditions, such as bone narrow failure syndromes and immune disorders. It increases the risk of severe bleeding, and therapies such as platelet transfusion or recombinant thrombopoietin are associated with a variety of complications. In contrast, the small-molecule eltrombopag, a thrombopoietin receptor antagonist, has been very effective in treating thrombocytopenia in patients with bone marrow failure. Kao et al. demonstrated that, in addition to targeting the thrombopoietin receptor, eltrombopag also chelates iron and that this chelating action enables it to improve the function of bone marrow stem cells. The authors also determined the mechanism linking iron chelation to hematopoietic stem cell maintenance, which may help facilitate the development of future treatments.