Thrombopoietins and thrombopoiesis: a clinical perspective.
Since the discovery of thrombopoietin four years ago there has been much interest in the clinical use of this growth factor and its impact on platelet transfusions. Two recombinant thrombopoietin molecules are currently under intense clinical investigation. One is a full-length, glycosylated thrombopoietin (rHuTPO) and the other is a non-glycosylated, truncated thrombopoietin coupled to polyethylene glycol (PEG-rHuMGDF). Both bind to the thrombopoietin receptor, c-mpl, and stimulate megakaryocyte growth and platelet production in vitro and in vivo. In early clinical studies these "Mpl ligands" have been effective in reducing thrombocytopenia after non-myeloablative but not after myeloablative chemotherapy. In transfusion medicine, they may serve to increase the yield of stem cell harvests, expand progenitor cells ex vivo and stimulate platelet apheresis donors. Their impact on platelet usage is still unclear but may be less than initially estimated.
Hematology/Oncology Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA. kuter.david@MGH.harvard.edu
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D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D009363:Neoplasm Proteins; D017713:Platelet Transfusion / Q000706:statistics & numerical data*; D010983:Plateletpheresis; D011092:Polyethylene Glycols / Q000009:adverse effects / Q000627:therapeutic use; D011518:Proto-Oncogene Proteins / Q000502:physiology; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D011993:Recombinant Fusion Proteins / Q000627:therapeutic use; D011994:Recombinant Proteins / Q000009:adverse effects / Q000627:therapeutic use; D013921:Thrombocytopenia / Q000628:therapy; D013926:Thrombopoietin / Q000009:adverse effects / Q000235:genetics / Q000627:therapeutic use*
D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C103117:polyethylene glycol-recombinant human megakaryocyte growth and development factor; C082218:MPL protein, human; D011092:Polyethylene Glycols; D013926:Thrombopoietin