关键词: 组织工程血管, 钙化, 平滑肌细胞, 支架, 动物实验, 组织构建

Abstract:

BACKGROUND: There are a few of reports about the long-term results of small caliber tissue engineered vascular graft. There are rarely studies of relationships between molecular level of tissue engineered vascular graft, long-term results of ion level, smooth muscle cells and calcification.
OBJECTIVE: To establish the small caliber tissue engineered vascular grafts with the decellularized porcine femoral artery matrix as a scaffold and dog vascular wall cells as seed cells, and implant in femoral arterial of the seed cell donor canine for 6 months, then to study the relationships between smooth muscle cells and calcification.
METHODS: Twelve mongrels were divided into a scaffold group (n=6) and a recellularizated scaffold group (n=6) at random. Femoral artery of mongrels was used as a control group. In the scaffold group, the decellularizated extracellular matrices of porcine femoral arteries were implanted in the right and left femoral arteries. Mongrels in the recellularizated scaffold group underwent implantation of the recellularizated extracellular matrices in the bilateral femoral arteries established by implantation of seed cells on the extracellular matrices and preconditioning in vitro. Tissue calcium content, smooth muscle cells density and pathological changes of the grafts and autologous femoral arteries were evaluated at 6 months.
RESULTS AND CONCLUSION: There was no significant stenosis and expansion in two groups at 6 months after small caliber tissue engineered vascular grafts implantation, but scanning electron microscopy showed the inner surface of the grafts was completely covered with endothelial cells in both groups, the stiffness and calcification plaque could be seen in the grafts of both groups. These changes were more obvious in the scaffold group. The calcification content in the scaffold group was higher than that in the recellularizated scaffold group and autologous femoral artery group (P < 0.01), and the calcification content in the recellularizated scaffold group was higher than that in the autologous femoral artery group (P < 0.01); the density of the smooth muscle cells in the grafts of recellularizated scaffold group was higher than that in the scaffold group (P < 0.01), and the smooth muscle cells in the grafts of recellularizated scaffold group and scaffold group was lower than that in the control group (P < 0.01). Ultrasonic examination presented that the systolic and diatolic movement in the grafts of both groups at the operation and at 6 months post-operation was weaker than that in the autologous femoral artery, and part of the pipeline did not have systolic and diastolic function. These findings show that smooth muscle cells are difficult to migrate to the middle layer of the extracellular matrices when the small caliber tissue engineered vascular graft constructed by decellularizated extracellular matrices of porcine femoral artery. The density of the smooth muscle cells in the middle layer is lower until 6 months after implantation, and the smooth muscle cells have the role of anti-calcification in tissue engineered vascular grafts.