IADR Abstract Archives
Direct and Indirect Angiogenesis via Human Endothelial Progenitor Cells
Objectives: Aim: We hypothesis that human endothelial progenitor cells (hEPCs) participate in angiogenesis directly by integrating into blood vessels walls, and indirectly by recruitment of resident endothelial cells via paracrine effect. In our previous rat calvaria model, we showed 9 fold increase in blood vessel density following hEPC transplantation. The aim of this study is to understand the role of hEPCs in angiogenesis through direct/indirect paracrine mechanism.
Methods: Methods: Blood was collected from 7 healthy donors (ages 19-44), and hEPCs were isolated, cultured and characterized by Flow cytometry (FACS). Cells were stained with DII membranal marker for in-vivo/ex-vivo tracking before transplantation. Nude mice (n=16) were allocated to control/test groups, β-TCP with (test) or without (control) 2X10-5 hEPCs were transplanted into subcutaneous pouches. Mice were sacrificed after three and eight weeks. In order to follow the direct engraftment of labeled cells, subcutaneous transplants were harvested and observed under in-vivo imaging system (IVIS) and confocal microscopy. Immunohistochemistry of human specific antigens (CD31, HNA) were used to localize the transplanted cell in the new tissue. Indirect effect of MSC recruitment was analyzed by mouse antigen CD73.
Results: Results: More than 95% of cells at FACS where CD31. Labeled cells were detected at 3 and 8 weeks with IVIS and confocal microscopy. In addition, CD31 and HNA showed the presence of hEPCs lining blood vessel walls and seen as clusters adjacent to TCP granules and to newly formed blood vessels. Human antigens were absent in the control specimens. Recruitment of resident mouse MSC was demonstrated by CD73, found in higher concentrations in the test compared with control group.
Conclusions: Conclusion: This study is one of the first studies that show the presence of hEPCs in the tissue at 8 weeks after transplantation. hEPCs directly participate in vessels formation and indirectly enhance recruitment of MSCs.
Methods: Methods: Blood was collected from 7 healthy donors (ages 19-44), and hEPCs were isolated, cultured and characterized by Flow cytometry (FACS). Cells were stained with DII membranal marker for in-vivo/ex-vivo tracking before transplantation. Nude mice (n=16) were allocated to control/test groups, β-TCP with (test) or without (control) 2X10-5 hEPCs were transplanted into subcutaneous pouches. Mice were sacrificed after three and eight weeks. In order to follow the direct engraftment of labeled cells, subcutaneous transplants were harvested and observed under in-vivo imaging system (IVIS) and confocal microscopy. Immunohistochemistry of human specific antigens (CD31, HNA) were used to localize the transplanted cell in the new tissue. Indirect effect of MSC recruitment was analyzed by mouse antigen CD73.
Results: Results: More than 95% of cells at FACS where CD31. Labeled cells were detected at 3 and 8 weeks with IVIS and confocal microscopy. In addition, CD31 and HNA showed the presence of hEPCs lining blood vessel walls and seen as clusters adjacent to TCP granules and to newly formed blood vessels. Human antigens were absent in the control specimens. Recruitment of resident mouse MSC was demonstrated by CD73, found in higher concentrations in the test compared with control group.
Conclusions: Conclusion: This study is one of the first studies that show the presence of hEPCs in the tissue at 8 weeks after transplantation. hEPCs directly participate in vessels formation and indirectly enhance recruitment of MSCs.