Recombinant human granulocyte-colony-stimulating factor-mobilized and apheresis-collected endothelial progenitor cells: a novel blood cell component for therapeutic vasculogenesis.
BACKGROUND
Endothelial progenitor cells (EPCs) have been identified among hematopoietic tissue-derived progenitor cells that are mobilized into the peripheral blood (PB) as a result of tissue injury. It therefore seems likely that circulating EPCs have therapeutic potential by aiding in the neovascularization of ischemic tissue. This study provides clinical data on the availability of circulating EPCs at steady state and after recombinant human granulocyte-colony-stimulating factor (rHuG-CSF) mobilization and their collection by leukapheresis.


METHODS
Eight healthy donors underwent rHuG-CSF treatment over 4 days, followed by leukapheresis. Blood samples taken before rHuG-CSF treatment and before apheresis as well as apheresis-collected samples were analyzed by flow cytometry and by real time reverse transcription-polymerase chain reaction for cells expressing EPC-specific surface markers and tissue markers, respectively, and for EPC colony-forming cells.


RESULTS
The median PB concentration of CD34+133+ vascular endothelial growth factor receptor-2 (VEGFR-2)-+ EPCs increased 8-fold from steady state to mobilized, and the concentration of CD34+133-VEGFR-2+ EPCs increased by 10-fold. This mobilization pattern was similar to that of hematopoietic CD34+, CD133+, and CD34+117+ progenitor cells. The increase in the median circulating colony-forming unit EPC concentration was 10-fold over baseline. The median absolute number of CD34+133+VEGFR-2+ cells collected by large-volume leukapheresis was 0.8 x 10(6) per kg of body weight. In addition, a small subset of immature CD133+34- cells coexpressing VEGFR-2 was identified in mobilized PB and in the apheresis collection. EPC-specific cells contained in the apheresis product were also identified as expressing mRNA for the CD31 antigen, Tie-2, and VEGFR-2.


CONCLUSIONS
Circulating EPCs represent a novel blood cell component that can be collected by apheresis in large quantities and can be used clinically, either unmanipulated or EPC-selected, for therapeutic vasculogenesis.
Körbling
Martin
M
Department of Blood and Marrow Transplantation, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA. mkorblin@mdanderson.org
Reuben
James M
JM
Gao
Hui
H
Lee
Bang-Ning
BN
Harris
David M
DM
Cogdell
David
D
Giralt
Sergio A
SA
Khouri
Issa F
IF
Saliba
Rima M
RM
Champlin
Richard E
RE
Zhang
Wei
W
Estrov
Zeev
Z
D000328:Adult; D000368:Aged; D000943:Antigens, Differentiation / Q000032:analysis; D001773:Blood Cells / Q000166:cytology*; D042783:Endothelial Cells / Q000166:cytology* / Q000637:transplantation; D015672:Erythroid Precursor Cells / Q000166:cytology* / Q000637:transplantation; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage*; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods; D006801:Humans; D007511:Ischemia / Q000628:therapy; D007937:Leukapheresis / Q000379:methods; D008297:Male; D008875:Middle Aged; D018919:Neovascularization, Physiologic; D011994:Recombinant Proteins; D033581:Stem Cell Transplantation
D000943:Antigens, Differentiation; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor