Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
Tissue Eng Part C Methods. 2011 Oct;17(10):983-91. doi: 10.1089/ten.TEC.2011.0070. Epub 2011 Jul 1.
Autologous heart valve tissue engineering relies on extracellular matrix production by cells seeded into a degrading scaffold material. The cells naturally exert traction forces to their surroundings, and due to an imbalance between scaffold, tissue, and these traction forces, stress is generated within the tissue. This stress results in compaction during culture and retraction of the leaflets at release of constraints, causing shape loss of the heart valve leaflets. In the present study, an in vitro model system has been developed to quantify stress generation, compaction, and retraction during culture and after release of constraints. Tissue-engineered (TE) constructs based on polyglycolic acid/poly-4-hydroxybutyrate scaffolds seeded with human vascular-derived cells were cultured for 4 weeks. Compaction in width was measured during culture, stress generation was measured during culture and after release of constraints at week 4, and contraction was measured after release of constraints at week 4. Both compaction and stress generation started after 2 weeks of culture and continued up to week 4. TE constructs compacted up to half of their original width and reached an internal stress of 6-8 kPa at week 4, which resulted in a retraction of 36%. The model system has provided a useful tool to unravel and optimize the balance between the different aspects of TE constructs to develop functional TE leaflets.
自体心脏瓣膜组织工程依赖于细胞接种到降解支架材料中产生细胞外基质。细胞自然向周围环境施加牵引力，由于支架、组织和这些牵引力之间的不平衡，组织内会产生应力。这种应力会导致培养过程中的压缩和约束释放时的瓣叶回缩，导致心脏瓣膜瓣叶形状丧失。在本研究中，开发了一种体外模型系统来量化培养过程中和约束释放后的应力产生、压缩和回缩。用人血管来源细胞接种的聚乙醇酸/聚-4-羟基丁酸支架构建的组织工程（TE）构建体培养了 4 周。在培养过程中测量宽度压缩，在培养过程中和第 4 周释放约束时测量应力产生，以及在第 4 周释放约束后测量收缩。压缩和应力产生都在培养 2 周后开始，并持续到第 4 周。TE 构建体在第 4 周时压缩至原始宽度的一半，达到 6-8kPa 的内部应力，导致 36%的回缩。该模型系统为揭示和优化 TE 构建体的不同方面之间的平衡提供了一个有用的工具，以开发功能性的 TE 瓣叶。
