细胞在小口径组织工程血管中的抗钙化作用

Anti-calcification effect of the cells in the small caliber tissue engineered vascular graft

背景:小口径组织工程血管的远期结果研究极少,尚未见到研究组织工程血管分子水平、离子水平远期结果和平滑肌细胞与钙化关系的报道。目的:利用脱细胞猪股动脉基质作为支架和犬血管壁细胞作为种子细胞体外构建小口径组织工程血管,植入种子细胞供体犬股动脉部位6个月,观察植入物中层平滑肌细胞与钙化的关系。方法:12只实验犬被随机分为支架组(n=6)和再细胞化组(n=6),自体股动脉被作为对照组;支架组犬接受猪股动脉经脱细胞后的基质支架植入双侧股动脉,再细胞化组犬接受受体血管壁细胞共同培养、联合种植于脱细胞的猪股动脉基质并体外预适应后植入血管壁细胞供体双侧股动脉位置;6个月后测定植入物和对照组股动脉组织钙含量、平滑肌密度和病理学变化。结果与结论:小口径组织工程血管植入后6个月检查见2组植入物无明显狭窄和扩张,扫描电镜示内表面均已完全内皮化,有管壁僵硬和局部钙化斑块形成,以上改变以支架组植入物更明显。支架组管道组织钙含量显著高于再细胞化组和自体股动脉(P<0.01),再细胞化组植入物组织钙含量亦显著高于自体股动脉(P<0.01);病理学检查示再细胞化组植入物平滑肌密度高于支架组(P<0.01),再细胞化组和支架组植入物平滑肌密度均低于对照组(P<0.01);超声检查见2组管道植入术后即刻与6个月后舒缩幅度较邻近自体股动脉舒缩幅度小,有部分管道无舒缩功能。结果提示,猪股动脉常规脱细胞方去获得的基质作为支架体外构建组织工程血管时,平滑肌细胞难于迁移至支架中层,中层平滑肌密度低,植入体内6个月后中层平滑肌细胞密度仍低,平滑肌细胞有抗血管钙化作用。

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（P0.01）,and the calcification content in the recellularizated scaffold group was higher than that in the autologous femoral artery group（P0.01）;the density of the smooth muscle cells in the grafts of recellularizated scaffold group was higher than that in the scaffold group（P0.01）,and the smooth muscle cells in the grafts of recellularizated scaffold group and scaffold group was lower than that in the control group（P0.01）.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.