Endothelial cells derived from circulating progenitors as an effective source to functional endothelialization of NaOH-treated poly(ε- caprolactone) films

Biomaterials have been widely used to prepare synthetic vascular grafts over the past thirty years, but the inherent thrombogenicity of their surface can lead to graft failure. Endothelial progenitor cells (EPC) are circulating premature cells able to differentiate in either myocardial or endothelial cells (EC). The therapeutic potential of these cells and its easy obtaining technique are important reasons why these cells could be used to improve the performance of vascular grafts. In this study, two different stages of differentiation of EC derived from EPC (EC₁ and EC₂) were characterized and cultured on poly(ε-caprolactone) (PCL) films treated with NaOH (PCL-NaOH). We investigated by immunolabeling the expression of CD31, von Willebrand factor (vWF), and endothelial nitric oxide synthase (eNOS) in these cells during the differentiation process. The proliferation, cell cycle, and mitochondrial function of EC₂ cultured on PCL-NaOH were evaluated at different times. The effect of this biomaterial on the nitric oxide (NO) content was also measured. The mature EC obtained from circulating progenitor cells (EC ₂) showed an appropriate growth and functionality on NaOH-treated films. They conserved their capacity to define vessel-like structures in culture and increased their basal NO production. These results underline the potential usefulness of these EC₂ to get a functional endothelialization of polymers with applications in vascular tissue engineering.