Laboratoire d'Organogénèse Expérimentale/LOEX, Centre de Recherche FRSQ du CHA Universitaire de Québec and Département de Chirurgie, Université Laval, Québec, QC, Canada.
Tissue Eng Part A. 2010 May;16(5):1737-47. doi: 10.1089/ten.TEA.2009.0313.
There is a clinical need for a functional tissue-engineered blood vessel because small-caliber arterial graft (<5 mm) applications are limited by the availability of suitable autologous vessels and suboptimal performances of synthetic grafts. This study presents an analysis of the mechanical properties of tissue-engineered vascular constructs produced using a novel single-step self-assembly approach. Briefly, the tissue-engineered vascular media were produced by culturing smooth muscle cell in the presence of sodium l-ascorbate until the formation of a cohesive tissue sheet. This sheet was then rolled around a tubular support to create a media construct. Alternatively, the tissue-engineered vascular adventitia was produced by rolling a tissue sheet obtained from dermal fibroblasts or saphenous vein fibroblasts. The standard self-assembly approach to obtain the two-layer tissue-engineered vascular constructs comprising both media and adventitia constructs consists of two steps in which tissue-engineered vascular media were first rolled on a tubular support and a tissue-engineered vascular adventitia was then rolled on top of the first layer. This study reports an original alternative method for assembling tissue-engineered vascular constructs comprising both media and an adventitia in a single step by rolling a continuous tissue sheet containing both cell types contiguously. This tissue sheet was produced by growing smooth muscle cells alongside fibroblasts (saphenous vein fibroblasts or dermal fibroblasts) in the same culture dish separated by a spacer, which is removed later in the culture period. The mechanical strength assessed by uniaxial tensile testing, burst pressure measurements, and viscoelastic behavior evaluated by stepwise stress relaxation tests reveals that the new single-step fabrication method significantly improves the mechanical properties of tissue-engineered vascular construct for both ultimate tensile strength and all the viscoelastic moduli.
临床需要一种功能性组织工程血管，因为小口径动脉移植物（<5mm）的应用受到合适的自体血管可用性和合成移植物性能不理想的限制。本研究分析了使用新型一步自组装方法生产的组织工程血管构建体的力学性能。简要地说，组织工程血管中膜是通过在存在抗坏血酸钠的情况下培养平滑肌细胞直到形成有凝聚力的组织片来生产的。然后将该片材卷绕在管状支架上以形成中膜构建体。或者，通过将从真皮成纤维细胞或大隐静脉成纤维细胞获得的组织片材卷起，可以生产组织工程血管外膜。获得包含中膜和外膜构建体的双层组织工程血管构建体的标准自组装方法包括两步，其中首先将组织工程血管中膜卷绕在管状支架上，然后将组织工程血管外膜卷绕在第一层的顶部。本研究报告了一种原始的替代方法，通过连续卷绕包含两种细胞类型的组织片材，在一步中组装包含中膜和外膜的组织工程血管构建体。通过在同一个培养皿中培养平滑肌细胞和成纤维细胞（大隐静脉成纤维细胞或真皮成纤维细胞），并通过间隔物将它们隔开，在培养后期再将间隔物去除来生产这种组织片材。通过单轴拉伸测试评估的机械强度、爆裂压力测量和通过逐步应力松弛测试评估的粘弹性行为表明，新的一步制造方法显著改善了组织工程血管构建体的机械性能，包括最终拉伸强度和所有粘弹性模量。
