29th Annual Meeting of the American Society of Photobiology

Downtown Marriot

Chicago, Il.

Seeding of photodynamic therapy treated vessels

Abstract-
There is a clinical need to overcome thrombosis after implantation of a bypass graft. Endothelial cell seeding is a potential application to create a non-thrombogenic graft. Photodynamic therapy (PDT) is a process which creates reactive species that eliminate cells within the vessel and generate extracellular matrix changes. The aim of this study was to use PDT to build an ideal natural scaffold seeded with human endothelial cells (EC), with the ultimate goal of creating a non-thrombogenic graft. New Zealand white rabbits received the photosensitizer chloroaluminum sulfonated phthalocyanine (5mg/kg IV) eighteen hours prior to PDT. Twenty-four hours after the procedure, the treated carotid artery was harvested and used for seeding. Prior to implantation, some EC were pretreated with an RGD peptide solution (350g/ml). Cells were seeded onto vessels and Dacron graft material. Untreated and RGD treated cells adhered to both PDT treated vessels and Dacron graft as shown by propidium iodide staining and confocal microscopy. The number of adherent cells was comparable on both Dacron and PDT treated vessel, as measured by MTS assay. Cells pretreated with the RGD peptide showed a 27% increase adherence thirty minutes following seeding on both Dacron graft and PDT treated vessels. Cellular function was confirmed by positive TNF- induced ELAM expression. This is the first report of EC seeding of PDT treated vessels, which shows promise as a possible means of creating an ideal small diameter vascular graft.

Keywords: crosslinked collagen, endothelial cells, bypass surgery