Observation of reconstructing vascular wall with tissue engineering technique ; evaluation of the process of tissue remodeling

对于血管移植的内皮化，来自外膜侧的毛细血管浸润是重要的，因为细胞分裂在吻合部位受到限制。临床应用血管假体植入术后，在血管移植愈合过程中存在愈合不足的问题。在人工器官领域引入治疗性血管生成并不那么成功。细胞、支架和生长因子的结合可能解决这一问题。作为组织工程技术重建血管壁的第一步，我们在兔耳室（REC）模型上研究了支架与细胞的关系。将棉型间胶原作为支架放置于腔内。支架组血管生成速度为100μm/d，未支架组血管生成速度为66μm/d。重组碱性成纤维细胞生长因子也能促进兔的血管生成和伤口愈合。在REC的愈合过程中，血管新生始于静脉侧的萌芽形成，然后成为成熟的动、静脉血管。血管壁的重构也被观察到。开始时，血管壁很薄，随着周细胞的增多而变厚。细胞、细胞外基质和生长因子的最佳混合是血管生成和血管重构成功的关键。

For endothelialization of vascular grafts, capillary infiltration from adventitia side is important, since cell division is limited at the anastomotic site. Healing insufficiency exists in the process of vascular graft healing after implantation of blood vessel prosthesis in clinic. The introduction of therapeutic angiogenesis was not so successful in the area of artificial organs. The combination of cells, scaffold and growth factors may solve the problem. As the first step of reconstructing vascular wall with tissue engineering technique, the relation between scaffold and cells was evaluated in a rabbit ear chamber (REC) model. As a scaffold, cotton type atelocollagen was placed in the camber. The speed of angiogenesis was 100μm/day in the REC with scaffold and 66μm/day without scaffold. With recombinant basic fibroblast growth factor, angiogenesis accompanied by wound healing was also accelerated in rabbits. In the process of healing in the REC, angiogenesis starts with sprout formation from venous side, then become mature vessels of artery and vein. The remodeling of vessel wall was also observed. At the beginning, the vessel wall was thin, and become thick with pericytes. It is important that using tissue engineering concept of cells, extracellular matrix and growth factor in best mix style is the key for success of angiogenesis and remodeling of blood vessels.