Fewer Circulating Endothelial Progenitor Cells in Newly Diagnosed Neovascular AMD Patients

Objective: Patients with age-related macular degeneration (AMD) exhibit pathologic neovascularization under the retina, with choroidal neovascularization (CNV) suggestive of defective angiogenesis. The endothelial progenitor cells (EPCs) present in the peripheral blood contribute to angiogenesis and vasculogenesis, and their regulation is altered in several vascular disorders. We investigated whether the numbers and functional properties of EPCs may be disordered in newly diagnosed neovascular AMD. Methods Fifteen suitable AMD patients and 10 controls matched for age, risk factors for atherosclerosis and use of medi- cation that could influence the circulating pool of EPCs were studied. Circulating EPCs were assayed by the col- ony-forming unit (CFU) method. The EPCs' adhesive capacity was studied by evaluating their ability to attach to fi- bronectin and cultured endothelial cells. Serum levels of vascular endothelial growth factor (VEGF) were studied and cor- related with EPC numbers. Results: The patients had significantly fewer circulating EPCs(16.5±2.8) compared to their controls (31±4.6; p=0.0085). The functional properties of both groups' EPCs were similar. Conclusions: The peripheral circulating pool of endothelial stem cells is altered in patients with newly diagnosed neovas- cular AMD, suggesting that pathologic angiogenesis may result from or influence the regulation of endothelial precursor circulation.