Optimization of human endothelial cell attachment to vascular graft polymers

Endothelial cells (EC) covering the blood-contacting surface of a prosthetic material could potentially enhance the subsequent nonthrombogenicity of the surface. In order to create such a surface, the EC must become attached to the surface, spread and ultimately form a monolayer. In this study we examined several factors that influence these processes. On ePTFE surfaces, surface pretreatment with human serum for 30 minutes at a concentration of 1.4 gm percent protein resulted in significantly more attached EC when compared to other concentrations or when compared to fetal calf serum or human serum albumin. The rate of EC spreading was strongly influenced by temperature, with a maximum occurring at 37 degrees C. During real-time video microscopy, it was noted that the rate of EC attachment and spreading was primarily dependent on arrival of the EC to the surface rather than attachment and spreading. Thus as a method of increasing EC delivery, the concept of filtering EC onto the graft lumenal surface was tested by pressurizing the graft lumen to speed EC delivery to the surface. This technique produced a 2 to 5-fold increase in EC attachment when compared to gravity forced cell deposition. We conclude that an ePTFE graft can be rapidly endothelialized using these simple measures.