Improved adherence of genetically modified endothelial cells to small-diameter expanded polytetrafluoroethylene grafts in a canine model

Abstract

Adherence of genetically modified endothelial cells to small-diameter expanded polytetrafluoroethylene grafts in an in vivo physiologic flow model is significantly improved when cells have a more prolonged recovery from G418 selection, when the graft lumen is more uniformly coated with fibronectin before EC seeding, and when seeded grafts are left longer in culture before implantation to develop cell lining stability. The short-term patency rate of these seeded grafts is not affected by increased cell retention; long-term graft patency data and luminal healing require further evaluation.

ECM-Based Materials in Cardiovascular Applications: Inherent Healing Potential and Augmentation of Native Regenerative Processes

“…Another option is to seed ECs on the luminal side of the graft in an in vitro bioreactor, prior to implantation, which involves multisteps processes of harvesting and culturing of autologous ECs or differentiated stem cells derived from the patient. Although in vivo studies using EPCs have shown excellent results in terms of graft endothelisation [148–151], very few clinical studies have been undertaken in order to determine its long-term effect on graft patency. Considering the multiple complications associated with re-endothelisation of synthetic materials in vivo and the limited availability of stem cell and cell culture laboratories in clinical environments, performing in vitro endothelisation before graft implantation is challenging [152].…”

Improving the Clinical Patency of Prosthetic Vascular and Coronary Bypass Grafts: The Role of Seeding and Tissue Engineering

“…Another novel approach has involved generating human ECs that constantly overexpress endothelial nitric oxide synthase (eNOS) and thus inhibit both platelet aggregation and SMC proliferation, the two factors most often resulting in intimal hyperplasia (105). Once these initial reports had been made, numerous in vitro and in vivo animal studies showed that it was possible to seed, via a two‐stage technique, such cells onto both vascular grafts and stents (90,91,106–108). These studies have not progressed on to clinical trials and have raised ethical questions on the role of gene therapy.…”

Dual cell seeding and the use of zymogen tissue plasminogen activator to improve cell retention on polytetrafluoroethylene grafts

“…The coating treatment was either the grafts were rinsed with the solutions and air-dried, or the solution was squeezed through the graft wall by holding both ends of solution-filled graft and pressuring the agent into the graft wall. 6 Beyond the seeding condition experiment, the fibronectin-squeezed grafts were used for all further cell seeding experiments. After the coating, the grafts were filled with cells (3 × 10 5 cells/mL) dissociated from 100-mm plates, heat-crimped at both ends, and rotated at 1 rpm for 2 hours at 37°C.…”

“…The precoating ECM on the surface of PTFE grafts has been shown to benefit cell seeding and adhesion. 5,6 We protease activity, once secreted from the cell, should exhibit limited digestion of the ECM. The increased tPA expression should therefore have little adverse effect on cellular adhesion while maintaining its thrombolysis ability when it is bound to fibrin within the thrombus.…”