Ex vivo differentiated endothelial and smooth muscle cells from human cord blood progenitors home to the angiogenic tumor vasculature.
OBJECTIVE
Recent studies have provided increasing evidence that postnatal neovascularization does not rely exclusively on sprouting of preexisting vessels, but also involves bone marrow-derived circulating endothelial precursors (BM-EPCs). Animal studies revealed that neovascularization of ischemic tissue can be enhanced by BM-EPCs transplantation. But a possible limitation to the use of vascular precursors for therapeutic angiogenesis is the relatively low number of these cells. In this study, we demonstrate that ex vivo expanded differentiated endothelial cells (ECs) and smooth muscle cells (SMCs), may home to the tumor vasculature allowing targeting of transgene expression to the neoangiogenic site.


METHODS
Mononuclear cells (MNCs) or CD34+ -enriched cells were purified from cord blood. We have defined culture conditions in which we observed two types of clones easily differentiated according to their morphology: cobblestone or spindle-shaped. Phenotypic characterization was assessed by immunocytochemistry, flow cytometry analysis and polymerase reaction with reverse transcription. Formation of capillary-like network in vitro was studied in three-dimensional collagen culture. And recruitment of these cells to a tumoral neoangiogenic site was assessed into tumor-bearing Severe Combined Immunodeficient (SCID) mouse model.


RESULTS
The cobblestone cells uniformly positive for CD31, VE-cadherin, vWF, VEGF R1 and R2, ecNOS and incorporating acetylated LDL were ECs. Spindle-shaped cells expressed alpha-smooth muscle actin (alpha-SMA), Smooth Muscle Heavy Chain (SMHC), SM22 and calponin. They also displayed a carbachol-induced contractility in a medium containing IGF1. So we concluded that spindle-shaped cells were SMCs. ECs and SMCs interacted with each other to form a capillary like network in three-dimensional type I collagen culture. Moreover, these ex vivo differentiated cells are able to home to the tumor vasculature.


CONCLUSIONS
We provide evidence that progenitors for ECs and SMCs circulate in human cord blood and differentiate into functional ECs and SMCs. These differentiated cells could provide a biomaterial for vascular cell therapy, because of their homing capacity to the neovascularization site.
Le Ricousse-Roussanne
Sophie
S
Institut des Vaisseaux et du Sang, Centre de Recherche de l'association Claude Bernard, Hôpital Lariboisière, 8 rue Guy Patin, 75475 Paris Cedex 10, France. sophie.lericousse@lrb.ap-hop-paris.fr
Barateau
Véronique
V
Contreres
Jean-Olivier
JO
Boval
Bernadette
B
Kraus-Berthier
Laurence
L
Tobelem
Gérard
G
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D045744:Cell Line, Tumor; D002465:Cell Movement; D042783:Endothelial Cells / Q000166:cytology*; D005312:Fetal Blood; D005434:Flow Cytometry; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D009130:Muscle, Smooth / Q000166:cytology*; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000032:analysis
D040281:Vascular Endothelial Growth Factor Receptor-1