In vitro model of endothelialization at anastomotic sites

Endothelial cell (EC) migration from native arteries to vascular prostheses is one of the most important healing processes of implanted artificial grafts, which results in endothelial cell coverage of the luminal surface of the graft. This article presents an in vitro model of endothelialization at the anastomotic site, which can provide cellular level information on morphologic reconstruction, and its substrate dependency. Test materials included polyethylene terephthalate (PET), segmented polyurethanes (SPUs), and glass with or without protein precoating (collagen, fibronectin, and albumin). In vitro endothelialization on these substrates was quantitatively determined by phase contrast microscopy. The results obtained show: 1) The fastest endothelialization rate was found on PET, followed by relatively hydrophobic SPU, and glass--the slowest was on hydrophilic SPU; and 2) Precoating with proteins drastically altered the cellular behaviors; collagen greatly enhanced endothelialization in vitro, followed by fibronectin. Precoating by albumin, however, greatly retarded endothelialization. The present study strongly suggests that unidirectional endothelialization at the anastomotic sites is controlled by the surface characteristics of graft materials.