Efficient in vivo bone formation by BMP-2 engineered human mesenchymal stem cells encapsulated in a projection stereolithographically fabricated hydrogel scaffold
Efficient in vivo bone formation by BMP-2 engineered human mesenchymal stem cells encapsulated in a projection stereolithographically fabricated hydrogel scaffold
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DOI：
10.1186/s13287-019-1350-6
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发表时间：
2019-08-14
影响因子：
7.5
通讯作者：
Tuan, Rocky S.
中科院分区：
文献类型：
--
作者：
Lin, Hang;Tang, Ying;Tuan, Rocky S.
背景干细胞骨组织工程在骨修复方面具有广阔的应用前景，但也面临着成骨能力不足、细胞支架结构灵活性有限等问题。方法本研究首先利用慢病毒载体体外转染人骨形态发生蛋白-2（BMP-2）基因的人骨髓源性干细胞（BMP-hBMSCs）。然后，我们使用先进的基于可见光的投影立体光刻（VL-PSL）技术将这些细胞引入水凝胶支架中，该技术与伴随的细胞包封相容，并适合计算机辅助建筑设计，以制造适合不同骨骼和缺陷中局部物理和结构变化的支架。结果BMP-hBMSCs包埋于支架内，在不添加BMP-2蛋白的情况下，BMP-2基因持续表达，细胞活力高，向成骨细胞分化。在严重联合免疫缺陷（SCID）小鼠中使用肌内植入模型进一步评估体内骨形成功效。显微计算机断层扫描（micro-CT）成像表明，早在植入后14天，BMP-hBMSC负载的构建体就能快速形成骨。组织学检查显示成熟的骨小梁结构和大量的血管形成。通过对植入细胞的追踪，我们还发现BMP-hBMSC直接参与了新骨的形成。结论本研究中开发的结构具有强大的自驱动成骨能力和计算机设计的结构，可用于大面积骨缺损或骨不连的定制临床修复。
Background Stem cell-based bone tissue engineering shows promise for bone repair but faces some challenges, such as insufficient osteogenesis and limited architecture flexibility of the cell-delivery scaffold. Methods In this study, we first used lentiviral constructs to transduce ex vivo human bone marrow-derived stem cells with human bone morphogenetic protein-2 (BMP-2) gene (BMP-hBMSCs). We then introduced these cells into a hydrogel scaffold using an advanced visible light-based projection stereolithography (VL-PSL) technology, which is compatible with concomitant cell encapsulation and amenable to computer-aided architectural design, to fabricate scaffolds fitting local physical and structural variations in different bones and defects. Results The results showed that the BMP-hBMSCs encapsulated within the scaffolds had high viability with sustained BMP-2 gene expression and differentiated toward an osteogenic lineage without the supplement of additional BMP-2 protein. In vivo bone formation efficacy was further assessed using an intramuscular implantation model in severe combined immunodeficiency (SCID) mice. Microcomputed tomography (micro-CT) imaging indicated rapid bone formation by the BMP-hBMSC-laden constructs as early as 14 days post-implantation. Histological examination revealed a mature trabecular bone structure with considerable vascularization. Through tracking of the implanted cells, we also found that BMP-hBMSC were directly involved in the new bone formation. Conclusions The robust, self-driven osteogenic capability and computer-designed architecture of the construct developed in this study should have potential applications for customized clinical repair of large bone defects or non-unions.