Robust angiogenic properties of cultured human peripheral blood-derived CD31⁺ cells

Background: Recently, we showed the angio-vasculogenic potential of uncultured human peripheral blood (hPB)-derived CD31(+) cells. However, thus far, the angiogenic property of the cultured hPB-derived CD31(+) (C-31(+)) cells is unknown. Thus, this study aimed to assess the angiogenic potency of C-31(+) cells on experimental ischemia.

Methods: CD31(+) and CD31(-) cells were isolated by magnetic bead separation technique, and cultured in EBM-2 complete medium for 6days. The expression of multiple angiogenic genes in these cells was measured using qRT-PCR. In addition, endothelial progenitor cell culture and matrigel network formation assays were performed. A mouse model of hindlimb ischemia induced by surgical resection of the right femoral artery was used, and the C-31(+) cells were intramuscularly transplanted into the ischemic area. Immunohistochemical analysis was also performed.

Results: C-31(+) cells exclusively showed higher colony-forming activity, and gave rise to EPCs. C-31(+) cells also induced higher endothelial network formation, and exhibited higher pro-angiogenic and lower inflammatory gene expression. In our ischemic hindlimb model, transplantation of C-31(+) cells induced increased blood perfusion (0.652±0.03 vs. 0.47±0.04; P<0.01) and increased capillary density (85±5.5 vs. 57±4.1; P<0.01) as compared to C-31(-) cells. In addition, angiogenic factors were markedly upregulated after the transplantation of C-31(+) cells, indicating that C-31(+) cells contributed to the neovascularization.

Conclusions: The high angiogenic and therapeutic potential of C-31(+) cells observed in our ischemic animal model suggests a novel role of hPB-derived cultured CD31(+) cells in the treatment of ischemic cardiovascular diseases.