Transmural endothelialization of vascular prostheses is regulated in vitro by Fibroblast Growth Factor 2 and heparan-like molecule

Endothelialization of vascular prostheses may result from transmural migration of endothelial cells. Angiogenesis is controlled by growth factors like Fibroblast Growth Factor 2 (FGF2) and regulators like heparan-like molecules. To that end, we used heparan-like molecules named RGTA for ReGeneraTing Agent. The RGTA11 used was a chemically derived dextran obtained by successive substitutions with carboxymethyl, benzylamide, and benzylamide sulfonate groups on glucose residues. This agent was further selected for its ability to bind, stabilize and prefect FGF2. We defined firstly the angiogenic capability of FGF2 in combination with RGTA11 on bovine aortic endothelial cells (BAEC) cultured on collagen I gels. Secondly the role of FGF2 and RGTA11 in transmural endothelialization was assessed in a three-dimensional in vitro model using a polyethylene terephtalate prosthesis included in collagen gel. BAEC seeded on the external face can migrate to the luminal face of the prosthesis. Microscopic and histological evaluations were performed at 4 and 7 days. Results showed that the addition of RGTA11 alone did not promote angiogenesis while FGF2 alone did. However, RGTA11 combined with FGF2 produced a significant acceleration in angiogenesis compared to FGF2 alone. This combination magnifies and enhances the angiogenic processes leading to endothelialization of luminal face through transmural cellular migration. Our data demonstrates that in vitro transmural endothelialization of porous vascular prostheses by BAEC cultured on collagen I gels is upregulated by RGTA11 combined with FGF2.