Time-course for in vitro development of basement membrane, gap junctions, and repair by adult endothelial cells seeded on precoated ePTFE

Objectives: to establish some functional characteristics after in vitro endothelialisation of precoated ePTFE grafts. Materials and methods: saphenous vein endothelial cells were confluently seeded on human serum-precoated ePTFE. Collagen I-precoated ePTFE served as control. Time-courses for development of laminin, collagen IV and connexin43 was followed-up with immunofluorescence. Endothelial migration and proliferation was studied with cresyl violet staining and tritiated thymidine-labelling. Results: six hours post-seeding, basement membrane components were visualised subendothelially as thin fibrils. After 24 h, there was a distinct fibril network, which did not seem to be further enhanced. Connexin43 was detected 6 h postseeding, and the number of intercellular connections appeared to be similar up to day 7. The time-courses were similar on serum- and collagen I-precoated ePTFE. Endothelialisation of a 4 mm wide gap showed migrating fronts largely composed of proliferating cells. The process was completed within 10 days on collagen I-precoated ePTFE, and 15 days on serum-precoated ePTFE. Conclusions: these findings suggest human endothelial cells, seeded on precoated ePTFE, maintain some differentiated functions seen in vivo . This is of importance for cell retention, functionality and endothelial repair of in vitro endothelialised ePTFE-grafts after implantation in man.