Preparation of porcine carotid arteries for vascular tissue engineering applications

Biomaterials derived from tissue continue to offer viable alternatives to synthetic materials when autologous materials are unavailable for transplantation due to their unique chem. and mech. properties. Tissue processing aims to stabilize the material against host degrdn. and render it immunol. inert by removing cellular material and crosslinking the structural proteins. It is clear that different approaches taken to achieve these goals have very different chem. and mech. effects on the material. We describe herein the development of a tissue processing methodol. to generate acellular scaffolds for tissue engineering small-diam. vascular grafts. Carotid arteries were isolated from Great White pigs and exposed to various solvent treatments, xylene, butanol, and ethanol to det. optimal parameters for the extn. of host lipids. The tissue was then exposed to a limited proteolysis with trypsin to disrupt cellular protein. This resulted in a controlled digestion that disrupted porcine nuclear DNA and cleared bulk cellular protein, leaving the more resistant structural proteins largely intact and retaining the bulk mech. properties of the matrix. Histol. anal. and SEM illustrated the complete removal of intact cells and nuclear material. The decellularized graft was stabilized by crosslinking with the photooxidative dye methylene green in the presence of 30,000 Lx of broadband light energy. High-performance liq. chromatog. anal. showed that the crosslinked tissue yielded 78.6% less hydroxyproline, compared with control tissue, after 20 h incubation with pepsin. Anal. of the crosslinked vessels burst-pressure and stress-strain characteristics have shown comparable mech. properties to those of control vessels. Assessment of in vitro cell adhesion and compatibility was conducted by seeding primary human umbilical vein endothelial cells and adult human vascular smooth muscle cells onto the lumenal and ablumenal surfaces, resp.; these cells were shown to adhere and proliferate under traditional static culture conditions. [on SciFinder (R)]