title: Efficacy of delayed administration of post-chemotherapy granulocyte colony-stimulating factor: evidence from murine studies of bone marrow cell kinetics.
abstract: The optimal schedule of post-chemotherapy granulocyte colony-stimulating factor (G-CSF) administration has not been determined. G-CSF is customarily started 24 hours after chemotherapy; however, clinical data demonstrated that delaying G-CSF until 5 days after completion of chemotherapy has not resulted in a longer duration of neutropenia. Here, we examined the optimal timing of post-chemotherapy G-CSF administration in a mouse model, to show that delayed administration does not postpone the appearance of mature granulocytes in the peripheral blood. We also investigated the mechanism of decreased efficacy of the early G-CSF application after chemotherapy by characterizing the changes in bone marrow cellular composition. To our knowledge, we demonstrate for the first time, that early after chemotherapy, the bone marrow is predominantly composed of mature residual granulocytes and very few progenitors and precursors, on which G-CSF would act to generate granulocytes. The point when immature progenitors reappear does not occur in murine bone marrow until 48 hours after a single dose of cyclophosphamide. Our results indicate that the bone marrow cellular composition early after discontinuation of chemotherapy is not optimal for G-CSF action on acceleration of myeloid recovery. Given the high cost of G-CSF prophylaxis, its delayed administration may potentially result in substantial economic benefits.
authors.affiliation: Texas Children's Cancer Center, Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas, USA. maxim.y.y.@gmail.com
authors.forename: Maxim
authors.initials: M
authors.lastname: Yankelevich
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Goodell
authors.forename: Joseph
authors.initials: J
authors.lastname: Kaplan
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D001854:Bone Marrow Cells / Q000145:classification / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D003114:Colony-Forming Units Assay; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000633:toxicity*; D004334:Drug Administration Schedule; D004353:Drug Evaluation, Preclinical; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage* / Q000191:economics / Q000627:therapeutic use; D006098:Granulocytes / Q000187:drug effects; D019650:Hematopoietic Stem Cell Mobilization; D007958:Leukocyte Count; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D038042:Myelopoiesis / Q000187:drug effects; D009503:Neutropenia / Q000209:etiology / Q000517:prevention & control*; D010976:Platelet Count; D019707:Receptors, Chemokine / Q000032:analysis; D011994:Recombinant Proteins; D013047:Specific Pathogen-Free Organisms
chemical_list: D018952:Antigens, CD34; C503133:Gr-1 protein, mouse; D019707:Receptors, Chemokine; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D003520:Cyclophosphamide