Trinity Centre for Bioengineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland.
J Mech Behav Biomed Mater. 2012 Apr;8:58-70. doi: 10.1016/j.jmbbm.2011.12.003. Epub 2011 Dec 27.
Several challenges persist when attempting to utilize decellularized tissue as a scaffold for vascular tissue engineering. Namely: poor cell infiltration/migration, excessive culture times associated with repopulating the scaffolds, and the achievement of a quiescent medial layer. In an attempt to create an optimum vascular scaffold, we customized the properties of decellularized porcine carotid arteries by: (i) creating cavities within the medial layer to allow direct injection of cells, and (ii) controlling the amount of collagen digestion to increase the porosity. Histological examination of our customized scaffold revealed a highly porous tissue structure containing consistent medial cavities running longitudinally through the porous scaffold wall. Mechanical testing of the customized scaffold showed that our minimal localized disruption to the ECM does not have a detrimental effect on the bulk mechanical response of the tissue. The results demonstrate that an increased stiffness and reduced distensibility occurs after decellularization when compared to the native tissue, however post scaffold customization we can revert the scaffold tensile properties back to that of the native tissue. This most noteworthy result occurs in the elastin dominant phase of the tensile response of the scaffold, indicating that no disruption has occurred to the elastin network by our decellularization and customization techniques. Additionally, the bulk seeding potential of the customized scaffold was demonstrated by direct injection of human smooth muscle cells through the medial cavities. The optimum cell dispersion was observed in the highest porosity scaffold, with large cell numbers retained within the medial layer after 24 h static culture. In summary, this study presents a novel customized decellularized vascular scaffold that has the capability of bulk seeding the media, and in tandem to this method, the porosity of the scaffold has been increased without compromising the mechanical integrity.
当试图将脱细胞组织用作血管组织工程的支架时，存在几个挑战。即：细胞渗透/迁移不良、重新填充支架所需的过长培养时间以及实现静止的中膜层。为了创建最佳的血管支架，我们通过以下两种方法来定制脱细胞猪颈动脉的特性：(i) 在中膜层内创建腔室，以便直接注射细胞，以及 (ii) 控制胶原蛋白消化的量以增加孔隙率。对我们定制的支架进行组织学检查显示，其具有高度多孔的组织结构，其中包含一致的中膜腔，这些腔室沿多孔支架壁纵向延伸。对定制支架进行的机械测试表明，我们对 ECM 的最小局部破坏不会对组织的整体力学响应产生不利影响。结果表明，与天然组织相比，脱细胞化后组织的刚度增加，可扩展性降低，但是在支架定制化后，我们可以将支架的拉伸性能恢复到天然组织的水平。这是最值得注意的结果，发生在支架拉伸响应的弹性蛋白主导阶段，表明我们的脱细胞化和定制化技术没有破坏弹性蛋白网络。此外，通过直接从中膜腔注射人平滑肌细胞，证明了定制支架的批量接种潜力。在最高孔隙率的支架中观察到最佳的细胞分散，在 24 小时静态培养后，大量细胞保留在中膜层内。总之，本研究提出了一种新颖的定制化脱细胞血管支架，该支架具有批量接种中膜的能力，并且与这种方法一起，支架的孔隙率增加而不会损害机械完整性。
