Over-dependence on existing synthetic scaffolds and insufficient vascularization limit the development of tissue engineered bone (TEB). The purpose of this study is to fabricate vascularized and scaffold-free bone tissue using cell sheet technology and to assess its feasibility to repair critical-sized calvarial defects in rats. Firstly, the pre-vascularized cell sheet was formed by seeding BMSC-derived endothelial cells (ECs) on an undifferentiated BMSCs cell sheet layer in vitro. After 3 days of co-culture, ECs migrated and rearranged to form lumens on the BMSC sheet. Secondly, osteogenic cell sheet was formed by inducing osteogenic differentiation of high density BMSCs. Then, the pre-vascularized cell sheet was stacked on BMSC-derived osteogenic cell sheet to fabricate a scaffold-free construct for bone regeneration. Finally, the scaffold-free construct with both angiogenic and osteogenic potential was implanted into critical-sized calvarial defects in adult Wistar rats. Results showed that more functional perfused blood vessels and new bone tissue formed in the pre-vascularized group than that in the controls (both empty and non-pre-vascularized cell sheet group). This study indicates a new promising strategy for bone tissue regeneration.

中文翻译：

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使用从骨髓来源的间充质干细胞中分化出来的内皮细胞和成骨细胞制造血管化和无支架的骨组织。

对现有合成支架的过度依赖和不足的血管形成限制了组织工程骨（TEB）的发展。这项研究的目的是使用细胞片技术制造血管化且无支架的骨组织，并评估其修复大鼠临界大小的颅骨缺损的可行性。首先，通过将BMSC来源的内皮细胞（EC）播种到未分化的BMSCs细胞片层上，形成预先血管化的细胞片。共培养3天后，EC迁移并重新排列以在BMSC片上形成管腔。其次，通过诱导高密度BMSCs的成骨分化形成成骨细胞片。然后，将预血管化的细胞片堆叠在源自BMSC的成骨细胞片上，以制造用于骨骼再生的无支架构建体。最后，将具有血管生成和成骨潜力的无支架构建体植入成年Wistar大鼠的临界大小颅盖缺损中。结果显示，与对照组（空的和未预血管化的细胞片组）相比，预血管化组中形成了更多的功能性灌注血管和新的骨组织。这项研究表明骨组织再生的一种新的有希望的策略。