Development Of Transgenic Tissue-Engineered Biologic Blood Vessel

Blood vessels tissue engineering offers the potential of providing vessels that can beused to replace diseased and damaged native blood vessels. The pathology that affects thesmall and medium-sized blood vessels is the primary cause of death in the USA. The acutevascular damage need to provide quickly the blood vessel replacement, the tissueengineering blood vessel (TEBV) must overcome allo-transplantation. In cardiac andperipheral bypass graft, these are usually replaced by autologous veins, or sometimes withautologous arteries. The veins are thin-walled vessels, lack the distinct molecular and tissueorganization of arteries, and deform more easily. In addition, many patients do not haveappropriate blood vessels for use as replacements. Synthetic vascular grafts such as ePTFEand Dacron have been used successfully in treating the pathology of large arteries (>6 mminternal diameter), when used to bypass graft that are less than 6 mm in diameter, havethrombosis rates greater than 40% after 6 months. Tissue engineering blood vessel includeproviding a conduit that will have sufficient strength not to burst with changes in bloodpressure, a vessel wall that is elastic and can withstand cyclic loading, matchingcompliance of the graft with the adjacent host vessel, and a lining of the lumen that isantithrombotic. At present, these study focus on the seeding of vascular cells, but there areno reports about how to decorate the seeding cells through gene engineering. It will makeTEBV get the antithrombotic ability and suit for cardiac bypass graft and acute vasculardamage. In addition, tissue engineered vascular graft must be preserved effectively beforevascular transplantation. Thus, decellularized vascular tissues provide a promisingapproach to improve upon current therapies for vascular disease. The diameter andbiomechanics of minipig's artery is suited for coronary artery bypass graft. We report analternative approach that combines human living vascular cells and a decellularized matrixto develop a tissue-engineered blood vessel. These recellularized blood vessels werecreated by seeding transgenic human neonatal vascular endothelial cells, smooth musclecells onto a decellularized, porcine aortic matrix and culturing the composite for up to 6weeks in a novel bioreactor that imposed dynamic fluid flow. Data and a discussion arepresented concerning a population of the porcine matrix by vascular cells, their metabolic activity, and the secretion of human extracellular matrix proteins that supplement the decellularized porcine matrix. Main results and conclusions are as follows.1. The results showed that Gal antigen is only expressed in endothelial cells. MHC antigen is not expressed, there are no significant difference in blood vessel compliance and form, the cells have been removed and fiber didn't rupture after trypsin treatment. These demonstrate that the antigen of pig aorta decreased significantly and the mechanics characteristic had no significant change; it can be used as material for vascular tissue engineering.2. With the help of DOTAP, endothelial cells and smooth muscle cells could be transfected with pEGFPEHA20-Nl. The positive cell clones were selected with G418. Immunofluorescence and western blot analysis showed that A20 could gain stable transfection and overexpression in the endothelial cells and smooth muscle cells. A20 gene can protect endothelial cells from all kinds of oxidative stress, low shear stress and burns serum damage and inhibit smooth muscle cells pathologic proliferation and phenotype changing.3. With the help of DOTAP, endothelial cells and smooth muscle cells could be transfected with pMANneoTGF1. Immunofluorescence and western blot analysis showed that TGF1 could gain stable transfection and overexpression in the endothelial cells and smooth muscle cells. TGFpi gene can increase two-three times elastin expression and increase the adhesion between smooth muscl...