Increase in circulating endothelial progenitor cells after aortic aneurysm repair

Rapid endothelialization of prosthetic vessels is essential to avoid fatal complications. We hypothesized that there may be mobilization of endothelial progenitor cells (EPCs) in patients who received aortic aneurysm repair, and measured the number of CD34-expressing EPCs (CD34+ cells) in these patients. Blood samples were taken preoperatively, 6, 24, and 48 h, and 7 days after surgery in 13 patients with aortic aneurysm. Samples were also obtained from ten age-matched control subjects. The number of CD34+ cells in the peripheral blood was quantified by flow cytometry. The levels of serum vascular endothelial growth factor (VEGF) were measured using an enzyme-linked immunosorbent assay kit. Baseline CD34+ cell counts in the peripheral blood showed a tendency to be lower in patients with aortic aneurysm compared with healthy control subjects. The number of CD34+ cells did not change over 48 h after aortic aneurysm repair; however, it had doubled by the 7th day. On the other hand, the baseline serum VEGF levels did not differ between the patients and control subjects. The VEGF levels increased gradually after vascular repair with a significant elevation after 48 h, which was followed by an increase in CD34+ cell counts. In conclusion, the circulating CD34+ cell counts and serum VEGF levels are increased after vascular prosthesis replacement in patients with aortic aneurysm, which might contribute to the rapid endothelialization of prosthetic vessels.