Magdi Yacoub Institute, Harefield Heart Science Centre, Imperial College London, Hill End Road, Harefield UB9 6JH, United Kingdom; Qatar Cardiovascular Research Center, Qatar Foundation, Qatar Science and Technology Park, PO Box 5825, Doha, Qatar.
Magdi Yacoub Institute, Harefield Heart Science Centre, Imperial College London, Hill End Road, Harefield UB9 6JH, United Kingdom.
Biomaterials. 2014 Feb;35(6):1833-44. doi: 10.1016/j.biomaterials.2013.10.061. Epub 2013 Dec 4.
Cells environment is increasingly recognized as an important function regulator through cell-matrix interactions. Extracellular matrix (ECM) anisotropy being a key component of heart valves properties, we have devised a method to create highly porous anisotropic nanofibrillar scaffolds and studied their suitability as cell-support and interactions with human adipose derived stem cells (hADSCs) and human valve interstitial cells (hVICs). Anisotropic nanofibrillar scaffolds were produced by a modified jet-spraying method that allows the formation of aligned nanofibres (600 nm) through air-stream diffraction of a polymer solution (poly (ε-caprolactone, PCL) and collection onto a variably rotating drum. The resulting matrices of high porosity (99%) mimicked valve mechanical anisotropy. Dynamically seeded hADSC and hVIC cultured on scaffolds up to 20 days revealed that hADSC and hVIC penetration within the matrices was improved by anisotropic organization. Within 10 days, cells populated the entire scaffolds thickness and produced ECM (collagen I, III and elastin). As a result, mechanical properties of the constructs were improved over culture, while remaining anisotropic. In contrast to isotropic matrices, anisotropy induced elongated hADSCs and hVICs morphology that followed nanofibres orientation. Interestingly, these morphological changes did not induce hADSC differentiation towards the mesoderm lineages while hVIC recovered a physiological phenotype over culture in the biomimetic matrices. Overall, this study indicates that highly porous anisotropic jet-sprayed matrices are interesting candidates for valve tissue engineering, through anisotropic mechanical properties, efficient cell population, conservation of stem cells phenotype and recovery of hVIC physiological phenotype.
细胞外环境越来越被认为是通过细胞-基质相互作用调节重要功能的因素。细胞外基质（ECM）各向异性是心脏瓣膜特性的关键组成部分，我们设计了一种方法来创建高度多孔各向异性纳米纤维支架，并研究了它们作为细胞支持物的适用性以及与人脂肪来源干细胞（hADSCs）和人瓣膜间质细胞（hVICs）的相互作用。各向异性纳米纤维支架通过改良的喷射纺丝方法制备，该方法通过聚合物溶液（聚己内酯，PCL）的气流衍射形成定向纳米纤维（600nm），并收集到可变速旋转的鼓上。所得高孔隙率（99%）的基质模拟了瓣膜的机械各向异性。在支架上动态接种 hADSC 和 hVIC 培养长达 20 天的结果表明，hADSC 和 hVIC 在基质内的穿透性通过各向异性组织得到了改善。在 10 天内，细胞填充了整个支架的厚度并产生了细胞外基质（胶原 I、III 和弹性蛋白）。结果，构建体的机械性能在培养过程中得到了提高，同时保持了各向异性。与各向同性基质相比，各向异性诱导了 hADSC 和 hVIC 形态的伸长，这些形态的变化沿着纳米纤维的方向。有趣的是，这些形态变化并没有诱导 hADSC 向中胚层谱系分化，而 hVIC 在仿生基质中培养时恢复了生理表型。总体而言，这项研究表明，高度多孔各向异性喷射纺丝基质通过各向异性力学性能、高效的细胞群体、干细胞表型的保留和 hVIC 生理表型的恢复，是心脏瓣膜组织工程的有前途的候选材料。
