Evaluation of mobilized peripheral blood CD34(+) cells from patients with severe coronary artery disease as a source of endothelial progenitor cells.
OBJECTIVE
The distinction between hematopoietic stem cells (HSC) and endothelial progenitor cells (EPC) is poorly defined. Co-expression of CD34 antigen with vascular endothelial growth factor (VEGF) receptor (VEGFR2) is currently used to define EPC ( 1 ).


METHODS
We evaluated the phenotypic and genomic characteristics of peripheral blood-derived CD34(+) cells in 22 granulocyte-colony-stimulating factor (G-CSF)-mobilized patients with severe coronary artery disease and assessed the influence of cell selection and storage on CD34(+) cell characteristics.


RESULTS
The median CD34(+) cell contents in the products before and after enrichment with the Isolex 300i Magnetic Cell Selection System were 0.2% and 82.5%, respectively. Cell-cycle analysis showed that 80% of CD34(+) cells were in G0 stage; 70% of the isolated CD34(+) cells co-expressed CD133, a marker for more immature progenitors. However, less than 5% of the isolated CD34(+) cells co-expressed the notch receptor Jagged-1 (CD339) and only 2% of the isolated CD34(+) population were positive for VEGFR2 (CD309). Molecular assessment of the isolated CD34(+) cells demonstrated extremely low expression of VEGFR2 and endothelial nitric oxide synthase (eNOS) and high expression of VEGF-A. Overnight storage at 4 degrees C did not significantly affect CD34(+) cell counts and viability. Storage in liquid nitrogen for 7 weeks did not affect the percentage of CD34(+) cells but was associated with a 26% drop in cell viability.


CONCLUSIONS
We have demonstrated that the majority of isolated CD34(+) cells consist of immature and quiescent cells that lack prototypic markers of EPC. High VEGF-A gene expression might be one of the mechanisms for CD34(+) cell-induced angiogenesis.
Zubair
Abba C
AC
Transfusion Medicine, Department of Pathology, Mayo Clinic, Jacksonville, Florida 32224, USA. zubair.abba@mayo.edu
Malik
Sunita
S
Paulsen
Athena
A
Ishikawa
Masakazu
M
McCoy
Christopher
C
Adams
Peter X
PX
Amrani
David
D
Costa
Marco
M
D000071916:AC133 Antigen; D000368:Aged; D042501:Angiogenic Proteins / Q000235:genetics / Q000378:metabolism; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D002452:Cell Count; D002453:Cell Cycle; D002469:Cell Separation; D002470:Cell Survival; D017322:Clinical Trials, Phase II as Topic; D003324:Coronary Artery Disease / Q000097:blood* / Q000473:pathology; D042783:Endothelial Cells / Q000166:cytology*; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D019650:Hematopoietic Stem Cell Mobilization; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014182:Transplantation, Autologous; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism
D000071916:AC133 Antigen; D042501:Angiogenic Proteins; D015703:Antigens, CD; D018952:Antigens, CD34; D015415:Biomarkers; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D040301:Vascular Endothelial Growth Factor Receptor-2