Mobilization of hematopoietic stem cells in a thalassemic mouse model: implications for human gene therapy of thalassemia.
Granulocyte colony-stimulating factor (G-CSF)-mobilized blood stem cells may become the preferable source of hematopoietic stem cells (HSCs) for gene therapy because of the higher yield of cells compared with conventional bone marrow harvesting. A G-CSF-associated risk of splenic rupture has been recognized in normal donors of HSCs, but limited information is available about the G-CSF effect in the presence of splenomegaly and extramedullary hematopoiesis. We investigated the G-CSF effect in a thalassemic mouse model (HBB(th-3)) as compared with a normal strain (C57BL/6), in terms of safety, mobilization efficacy, and distribution of stem cells among hematopoietic compartments. There was no death or clinical sequelae of splenic rupture in G-CSF-treated animals of either strain; however, hemorrhagic infarcts in the spleen were detected with low frequency in G-CSF-treated HBB(th-3) mice (12.5%). HBB(th-3) mice mobilized less effectively than C57BL/6 mice (Lin(-)Sca-1(+)c-Kit(+) cells/microl of peripheral blood mononuclear cells [PBMCs]: 90 +/- 55 vs. 255 +/- 174, respectively, p = 0.01; CFU-GM/ml PBMCs: 390 +/- 262 vs. 1131 +/- 875, p = 0.01) because of increased splenic trapping of hematopoietic stem and progenitor cells (Lin(-)Sca-1(+)c-Kit(+) cells per spleen (x10(5)): 487 +/- 35 vs. 109 +/- 19.6, p = 0.01; CFU-GM per spleen (x10(2)): 1470 +/- 347 vs. 530 +/- 425, p = 0.0006). Splenectomy restored the mobilization proficiency of thalassemic mice at comparable levels to normal mice and resulted in the development of a hematopoietic compensatory mechanism in the thalassemic liver that protected splenectomized mice from severe anemia. Our data imply that, in view of human gene therapy for thalassemia, either multiple cycles or alternative ways of mobilization may be required for a sufficient yield of transplantable HSCs. In addition, strategies to minimize the risk of G-CSF-induced splenic infarcts should be explored in a clinical setting.
Yannaki
Evangelia
E
Gene and Cell Therapy Center, Hematology Department-BMT Unit, George Papanicolaou Hospital, Thessaloniki 57010, Greece. eyannaki@u.washington.edu
Psatha
Nikoleta
N
Athanasiou
Evangelia
E
Karponi
Garyfalia
G
Constantinou
Varnavas
V
Papadopoulou
Anastasia
A
Tasouli
Athanasia
A
Kaloyannidis
Panayotis
P
Batsis
Ioannis
I
Arsenakis
Minas
M
Anagnostopoulos
Achilles
A
Fassas
Athanasios
A
D000818:Animals; D004195:Disease Models, Animal; D005434:Flow Cytometry; D015316:Genetic Therapy; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006454:Hemoglobins / Q000502:physiology; D006801:Humans; D007124:Immunoenzyme Techniques; D008099:Liver / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011994:Recombinant Proteins; D013154:Spleen / Q000378:metabolism / Q000473:pathology; D013156:Splenectomy; D013789:Thalassemia / Q000235:genetics / Q000378:metabolism / Q000628:therapy*
D006454:Hemoglobins; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor