My project focuses on the proteoglycan component of vascular tissue and use molecular genetic approaches to express specific proteoglycan genes by smooth muscle and fibroblast cells to assemble experimentally defined combinations of extracellular matrices (ECMs) to be used in the tissue engineering of a blood vessel. Two major shortcomings of existing tissue-engineered matrices are 1) the use of non-biocompatible matrix components and structural organization, and 2) the lack of functional and stable elastic fibers. Previously in the Wight laboratory, proteoglycan ECM genes involved in collagen fiber packing and organization (decorin) and elastin fiber formation (versican, V3 isoform) were identified. I am now characterizing the biomechanical properties of tissue sheets expressing these proteoglycans, and trying to specifically characterize the relationship between versican V3 and elastic fibrilogenesis. The resultant tissue sheets are being rolled around a mandrel support and undergoing further conditioning in flow-though, tubular culture system. These matrix defined neovessels are to be characterized in terms of their physical properties (burst strength, elastic modulus, compliance), histologic structure (staining and immunocytochemisty), composition and morphology (Western and Northern analysis; EM, light microscopy; desmosine crosslink and morphometric mass analysis), and compared to normal blood vessels of the same caliber. The long-term aims are to seed the luminal surface with endothelial cells, precondition the grafts, then evaluate the engineered tissue in vivo for patency, structural integrity, and thrombus.