Combination of inductive effect of lipopolysaccharide and in situ mechanical conditioning for forming an autologous vascular graft in vivo.

Autologous vascular grafts have the advantages of better biocompatibility and prognosis. However, previous studies that implanted bare polymer tubes in animals to grow autologous tubular tissues were limited by their poor yield rates and stability. To enhance the yield rate of the tubular tissue, we employed a design with the addition of overlaid autologous whole blood scaffold containing lipopolysaccharides (LPS). Furthermore, we applied in vivo dynamic mechanical stimuli through cyclically inflatable silicone tube to improve the mechanical properties of the harvested tissues. The effectiveness of the modification was examined by implanting the tubes in the peritoneal cavity of rats. A group without mechanical stimuli served as the controls. After 24 days of culture including 16 days of cyclic mechanical stimuli, we harvested the tubular tissue forming on the silicone tube for analysis or further autologous interposition vascular grafting. In comparison with those without cyclic dynamic stimuli, tubular tissues with this treatment during in vivo culture had stronger mechanical properties, better smooth muscle differentiation, and more collagen and elastin expression by the end of incubation period in the peritoneal cavity. The grafts remained patent after 4 months of implantation and showed the presence of endothelial and smooth muscle cells. This model shows a new prospect for vascular tissue engineering.