The purpose of this project is to determine in vitro, which substrate surface properties of vascular prosthetic materials are most critical for spontaneous human endothelial ingrowth and repopulation. Using cultured adult human arterial and venous endothelial cells, we will determine: 1. How surface texture, critical surface tension, and adsorbed protein coatings affect human vascular endothelial cell attachment, migration, resistance to shear, and subsequent growth. 2. How the above substrate properties affect the extracellular matrix elaborated by adult human vascular endothelial cells (both qualitatively with immunofluorescent microscopy, and quantitatively with ELISA assays) using monoclonal and polyclonal antibodies to fibronectin, laminin, and type IV collagen. 3. If graft surfaces (in humans) change at some time after implantation to become inhospitable to endothelial cell growth. This will be done by studying the growth of human endothelial cells on the luminal surfaces of explanted human vascular grafts. Data obtained from these studies will contribute to the design of a graft with surface properties specifically chosen to promote optimal human vascular endothelial cell growth and migration. Such a graft could obviate the need for cell seeding, and allow spontaneous endothelialization of vascular prostheses in man.