The persistence of electrostatically seeded endothelial cells lining a small diameter expanded polytetrafluoroethylene vascular graft

Purpose: The purpose of this study was to evaluate the persistence of electrostatically seeded endothelial cells (ECs) lining an expanded polytetrafluorethylene (e-PTFE) graft after one week exposure to in vivo circulation in a canine femoral artery bypass model. This was accomplished by visualizing the PKH 26 (red fluorescent) label placed in the EC membranes prior to the seeding procedure. Furthermore, this study was performed to confirm that the source of the ECs lining the graft were those from the initial inoculum. Methods: This evaluation consisted of harvesting autologous, canine jugular vein ECs, PKH 26 labeling of the ECs, electrostatic EC seeding the e-PTFE grafts (4mm GORE-TEX®, Length = 6cm), implanting the grafts (femoral artery model) for one week, and explanting the grafts for light, fluorescent and scanning electron microscopy evaluations of the luminal surface. Results: The unseeded grafts (controls) had a mean fluorescence surface coverage of 6.82 ± 7.19%, while the EC seeded grafts had a mean of 90.3 ± 14.3% which is significantly (p<0.001) different from the controls. Overall, the seeding time including the EC harvesting and PKH 26 labeling protocol was approximately 75 min. Conclusions: The electrostatically seeded ECs persisted after implantation of the graft as demonstrated by the PKH 26 labeling data. The fluorescent data also demonstrated that the neointima formed (EC luminal surface coverage) one week after implantation was in fact derived from the ECs initially seeded as determined by the abundance of the labeled ECs.