GFP-transduced CD34+ and Lin- CD34- hematopoietic stem cells did not adopt a cardiac phenotype in a nonhuman primate model of myocardial infarct.
OBJECTIVE
Studies in mice have reported contradictory results on the contribution of bone marrow cells to myocardial regeneration. This study aims to evaluate their ability to differentiate into cells of cardiac lineage in a nonhuman primate mode of myocardial infarct.


METHODS
Lin(-)CD34(-) and CD34(+)-enriched bone marrow cells or mobilized peripheral blood cells were transduced with green fluorescent protein (GFP) and injected directly into ischemic myocardium. The fate of the transplanted cells was evaluated using quantitative reverse transcription polymerase chain reaction (QRT-PCR) and immunohistology. Animals were followed-up using echocardiography.


RESULTS
QRT-PCR analysis detected from 3% to 10% of the original number of administered GFP(+) cells after 7 days. These GFP(+) cells did not express cardiac tissue-specific markers, but were immunophenotypically consistent with undifferentiated hematopoietic cells. The local production of vascular endothelial growth factor, measured by QRT-PCR, was approximately doubled as compared to the untreated infarcted control heart. Three months after hematopoietic stem cell (HSC) administration, no GFP(+) cells were detected and no evidence of regeneration of the infarcted region was found by histological examination. In contrast, a high level of matrix metalloproteinase 2 was measured in infarct and peri-infarct area. At this time, an improved ejection fraction and decreased left ventricular chamber dimension, which might be also related to a natural course after reperfusion, were observed.


CONCLUSIONS
Our data show that GFP(+) CD34(+) and Lin(-)CD34(-)-enriched HSC do not differentiate into cardiomyocytes or into endothelial cells in the infarcted myocardium and that the local production of some growth factors had no positive effect on myocardial regeneration after 3 months.
Norol
Francoise
F
Department of Biotherapy, AP-HP, Groupe Hospitalier Pitié Salpêtrière, 47-83 Boulevard de l'Hôpital, 75013 Paris, France. f.norol@psl.ap-hop-paris.fr
Bonnet
Nicolas
N
Peinnequin
Andre
A
Chretien
Fabrice
F
Legrand
Roger
R
Isnard
Richard
R
Herodin
Francis
F
Baillou
Claude
C
Delache
Benoit
B
Negre
Didier
D
Klatzmann
David
D
Vernant
Jean-Paul
JP
Lemoine
Francios M
FM
D000818:Animals; D018952:Antigens, CD34 / Q000276:immunology*; D001483:Base Sequence; D017931:DNA Primers; D004195:Disease Models, Animal; D005260:Female; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D008252:Macaca fascicularis; D008297:Male; D009203:Myocardial Infarction / Q000235:genetics / Q000276:immunology* / Q000601:surgery; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015302:Simian Immunodeficiency Virus / Q000235:genetics; D033581:Stem Cell Transplantation; D014161:Transduction, Genetic
D018952:Antigens, CD34; D017931:DNA Primers; D049452:Green Fluorescent Proteins