Use of Polyelectrolyte Films in Vascular Tissue Engineering

Vascular diseases with their high morbidity and mortality are a major challenge for medical science, engaging the best minds in modern medicine. The development of antithrombogenic surfaces still remains a huge challenge in the vascular tissue engineering field. Various researchers have expanded surface coating procedures allowing endothelial cells (EC) adhesion and retention on vascular substitutes or by incorporating some of the mechanisms employed by vascular endothelial cells i.e. heparin. The short in vivo patency of these grafts is related. Our group study evaluates a new surface modification based on polyelectrolyte building. The layer by layer self assembly and the result in polyelectrolyte multilayer films (PEM) became also in a recent past a challenging, simple and versatile way to engineer surfaces with highly specific properties. Previous studies indicated that the poly(sodium-4 styrene sulfonate)/poly (allylamine hydrochloride) PSS/PAH multilayered films when ended by PAH induce strong adhesion and retention of mature EC which spread and keep their phenotype as well on glass [1,2], on expanded polytetrafluoroethylene ePTFE [3] and on cryopreserved arteries [4,5]. The mechanical properties (compliance), leading to early intimal hyperplasia and graft failure, were lost after artery cryopreservation. We have demonstrated the compliance restoration of PEM treated cryopreserved close to native arteries [5]. The use of an autologous EC source avoids the immunological rejections of the grafts. With an autologous origin, high proliferation capacity and potentialities to proliferate and differentiate into matures EC, the endothelial progenitor cells (EPC) have raised huge interest and offer new opportunities in vascular engineering. Currents protocols for isolation and differentiation of EPC from peripheral blood requires at least 1 month to observe an endothelium-like morphology and about 2 months for confluent EC monolayer. The EPC cultivated on PEM treated glasses showed a monolayer development after only 14 days of culture. The morphological appearance and mature phenotype markers expression and repartition of the monolayer cells are close to mature EC [6]. These main results have led to French patent deposit in June 2007[7].