The angiogenic gene profile of circulating endothelial progenitor cells from ischemic stroke patients

Background: The identification of circulating endothelial progenitor cells (EPCs) has introduced new possibilities for cell-based treatments for stroke. We tested the angiogenic gene expression of outgrowth endothelial cells (OECs), an EPC subtype capable to shape vessel structures. Methods: OECs (at colony or mature stages) from ischemic stroke patients (n=8) were characterized using the RT2 Profiler (TM) human angiogenesis PCR Array, and human microvascular endothelial cells (hCMEC/D3) were used as an expression reference of endothelial cells. Results: Colony-OECs showed higher expression of CCL2, ID3, IGF-1, MMP9, TGFBR1, TNFAIP2, TNF and TGFB1. However, BAI-1, NRP2, THBS1, MMP2 and VEGFC expression was increased in mature-OECs (p<0.05). ID3 (p=0.008) and TGFBR1 (p=0.03) genes remained significantly overexpressed in colony-OECs compared to mature-OECs or hCMEC/D3. MMP9 levels were significantly increased in colony-OECs (p=0.025) compared to mature-OECs. Moreover, MMP-2, VEGF-C, THBS1 and NRP-2 gene expression was also significantly increased in mature-OECs compared to hCMEC/D3 (p<0.05). Some of these genes were positively validated by RT-PCR. Conclusion: Our study shows that OECs from stroke patients present higher levels of pro-angiogenic factors at early stages, decreasing in mature OECs when they become more similar to mature microvascular endothelial cells.