Cell Seeding for Small Diameter ePTFE Vascular Grafts: A Comparison Between Adult Human Endothelial and Mesothelial Cells George J.L. Thomson, FRCS, Rajiv Vohra, FRCS, Michael G. Walker, ChM, FRCS, zyxwvut Manchester, United Kingdom zyxw A series of experiments was performed to compare the ability of adult human endothelial and mesothelial cells to attach and spread upon ePTFE graft material. Both cell types were harvested enzymatically and grown in culture. Two types of adhesion assay were used to assess the ability of the cultured cells to attach to ePTFE either uncoated or precoated with a variety of substrate proteins. The results showed that fibronectin, laminin, type 4 collagen and preclotted blood all greatly improve the attachment rate of endothelium to ePTFE. The extracellular matrix proteins, however, give patchy cell attachment, whereas cells seeded onto preclotted ePTFE form a virtually confluent monolayer after one hour’s incubation. The matrix proteins similarly improve mesothelial attachment, although in all cases attached cells remain largely rounded up, with relatively few spreading on the surface. Mesothelial attachment to preclotted ePTFE is no better than attachment to the untreated material. It would seem that a preclotted graft seeded with endothelial cells is the combination most likely to result in a confluent monolayer within one hour. KEY WORDS: Cell seeding; vascular grafts; endothelial cells; mesothelial cells; grafts. Since the concept of endothelial seeding of pros- thetic vascular grafts was first introduced in zyxwvut 1978 [ 11, many studies have confirmed the feasibility of this process in promoting the development of a functional endothelial lining, resulting in improved patency [2-41. The majority of such studies have involved the use of venous endothelial cells derived zyxwvu From the Department of Vascular Surgery, Manchester Royal Infirmary, Manchester, United Kingdom. Presented at the Third Symposium on Endothelial Seed- ing, Indiana University School of Medicine, Indianapo- lis, Indiana, October 20-21, 1988. Reprint requests: M.G. Walker, ChM, FRCS, Depart- ment zyxwvutsrqp of Vascular Surgery, Manchester Royal Injrmary , Oxford Road, Manchester MI3 9WL, United Kingdom. from animal sources or from human umbilical vein [5], relatively few using adult human cells. More recently, it has been suggested that seeding with omentally-derived mesothelial cells may be equally effective in promoting a functional cellular lining within a prosthetic graft [6,7]. As the avail- ability of venous endothelial cells for seeding pur- poses is limited by tissue source and inefficient harvesting methods, the distinct advantage of using mesothelial cells is their relative abundance. As yet no direct comparison between these cell types has been made with regard to their relative abilities to attach and spread upon prosthetic graft surfaces. This is clearly of great importance, as rapid attachment and spreading are essential for any cell type used for seeding purposes. The present study was designed to compare the zy 140