Human endothelium on vascular prostheses modified by extracellular matrix proteins in a flow experiment

Artificial vascular prostheses are used for bypass surgery. Thrombogenicity often cause graft occlusion. Targeted surface alterations including cell seeding may improve the haemocompatibility. Knitted commercial tubular PET (polyethylene terephtalate) vascular prostheses with collagen impregnation were modified by adsorption of laminin (LM) or coating with fibrin network (FB) on the luminal surface. Human endothelial cells were harvested, cultured and seeded at the density of 150x103 cells/cm2 on all grafts. The cell lining was continuously visualized and quantified. The retention was 21%, 37% and only 2% of the seeding density on the unmodified (UM), LM- and FB-coated grafts, respectively. These seeded prostheses were exposed to a laminar shear stress (SS) 15 dynes/cm2 for 40 minutes (UM, LM, FB) and 120 min (UM, LM) in a chamber simulating blood circulation. The SS was exluded in static (ST) control grafts. After 40 min-SS the cell numbers were 78%, 27% and 72% for the UM, LM and FB prosthesis compared to the ST. The cell densities were 61% and 57% on the UM and LM after 120 min-SS. To conclude, the endothelium formed a confluent layer whereas laminin immobilisation improved endothelial adhesion but not the flow resistance. Reverse effect was observed on fibrin coating.