Mobilization of circulating endothelial progenitor cells after endovascular therapy for ruptured cerebral aneurysms

Emerging evidence shows that circulating endothelial progenitor cells (EPCs) promote regeneration of the endothelium at sites of vessel injury. This study was designed to test the hypothesis that EPCs are mobilized in patients who had ruptured cerebral aneurysm (CA) and underwent endovascular therapy. Fourteen patients with ruptured CAs were recruited and blood samples were analyzed after coil embolization surgery. Blood samples were also obtained from 18 healthy control subjects who had no evidence of CAs and did not undergo endovascular surgery. We measured the numbers of circulating EPCs, levels of plasma vascular endothelial growth factor (VEGF) and platelet counts. EPCs significantly increased in patients with ruptured CAs and underwent surgical coil embolization, reaching a peak level on day 14 post operation. The levels of plasma VEGF and platelet counts also significantly increased in parallel with the increase in EPCs, leading to significant positive correlations of circulating EPCs with VEGF in plasma (r=0.636, P<0.01) and platelet counts (r=0.721, P<0.001), respectively. The finding suggests that EPCs are mobilized upon surgery and may play a critical role in repairing injured vascular endothelium. Levels of EPCs in peripheral blood could also serve as a prognostic marker for the outcomes of ruptured cerebral aneurysms after surgical repair.