Scaffold Architecture and Matrix Strain Modulate Mesenchymal Cell and Microvascular Growth and Development in a Time Dependent Manner
Scaffold Architecture and Matrix Strain Modulate Mesenchymal Cell and Microvascular Growth and Development in a Time Dependent Manner
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DOI：
10.1007/s12195-020-00648-7
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发表时间：
2020-08-18
影响因子：
2.8
通讯作者：
Guda, Teja
中科院分区：
文献类型：
--
作者：
Chiou, Gennifer;Jui, Elysa;Guda, Teja
背景由于依赖于良好的血管网络，体积型组织工程构建物的发展受到限制。支架孔径和基质的机械性质决定了细胞附着、增殖和连续的组织形态发生。我们假设支架孔结构也控制间质-血管相互作用在形态发生。方法将骨髓间充质干细胞（MSCs）分别接种于450、340和250 μ m孔径的羟基磷灰石支架上，并将其与20 mg/mL纤维蛋白水凝胶中的微血管碎片（MVF）进行21 d的体外相互作用，并与不含支架但同时含有MSCs和MVF的纤维蛋白水凝胶进行比较。在所有组中进行mRNA测序，并开发计算力学模型以验证结构对预测血管化的影响，所述血管化是由支架表面处比孔内部更硬的基质行为驱动的。结果14 d时脱钙支架的凝集素染色显示血管继续生长、分支和网络形成。纤维蛋白凝胶对铺展的毛细血管网络形成没有抵抗力，在450 μ m的孔内有更大的血管环，血管桥接在250 μ m的孔上。观察到支架中的血管生长受到缺氧和连续的血管生成信号的刺激。纤维蛋白凝胶显示VEGF表达呈线性倍数增加，而BMP 2无变化。在支架内，相对于纤维蛋白，VEGF在第7天和第14天之间成倍增加，BMP 2在第3天和第7天之间早期成倍增加。在支架组中存在基于雅普/taz的hippo信号传导和机械转导的证据。通过计算建模确定的血管生长模型与实验观察到的趋势相匹配。结论支架系统和机械力传感基质系统之间缺氧信号的不同性质是导致成骨细胞和微血管生长差异的主要原因。计算模型涉及支架结构在支配分支形态和应变的水凝胶内的孔在支配血管长度。
Background Volumetric tissue-engineered constructs are limited in development due to the dependence on well-formed vascular networks. Scaffold pore size and the mechanical properties of the matrix dictates cell attachment, proliferation and successive tissue morphogenesis. We hypothesize scaffold pore architecture also controls stromal-vessel interactions during morphogenesis. Methods The interaction between mesenchymal stem cells (MSCs) seeded on hydroxyapatite scaffolds of 450, 340, and 250 mu m pores and microvascular fragments (MVFs) seeded within 20 mg/mL fibrin hydrogels that were cast into the cell-seeded scaffolds, was assessedin vitroover 21 days and compared to the fibrin hydrogels without scaffold but containing both MSCs and MVFs. mRNA sequencing was performed across all groups and a computational mechanics model was developed to validate architecture effects on predicting vascularization driven by stiffer matrix behavior at scaffold surfaces compared to the pore interior. Results Lectin staining of decalcified scaffolds showed continued vessel growth, branching and network formation at 14 days. The fibrin gel provides no resistance to spread-out capillary networks formation, with greater vessel loops within the 450 mu m pores and vessels bridging across 250 mu m pores. Vessel growth in the scaffolds was observed to be stimulated by hypoxia and successive angiogenic signaling. Fibrin gels showed linear fold increase in VEGF expression and no change in BMP2. Within scaffolds, there was multiple fold increase in VEGF between days 7 and 14 and early multiple fold increases in BMP2 between days 3 and 7, relative to fibrin. There was evidence of yap/taz based hippo signaling and mechanotransduction in the scaffold groups. The vessel growth models determined by computational modeling matched the trends observed experimentally. Conclusion The differing nature of hypoxia signaling between scaffold systems and mechano-transduction sensing matrix mechanics were primarily responsible for differences in osteogenic cell and microvessel growth. The computational model implicated scaffold architecture in dictating branching morphology and strain in the hydrogel within pores in dictating vessel lengths.