1 Department of Plastic and Reconstructive Surgery, Shanghai Key Laboratory of Tissue Engineering Research, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
2 National Tissue Engineering Center of China, Shanghai, PR China.
J Biomater Appl. 2018 Aug;33(2):182-195. doi: 10.1177/0885328218784370. Epub 2018 Jun 27.
Insufficient neo-vascularization of in vivo implanted cell-seeded scaffold remains a major bottleneck for clinical translation of engineered bone formation. Demineralized bone matrix is an ideal bone scaffold for bone engineering due to its structural and biochemical components similar to those of native bone. We hypothesized that the microcarrier form of demineralized bone matrix favors ingrowth of vessels and bone regeneration upon in vivo implantation. In this study, a rat model of femoral vessel pedicle-based bone engineering was employed by filling the demineralized bone matrix scaffolds inside a silicone chamber that surrounded the vessel pedicles, and to compare the efficiency of vascularized bone regeneration between microcarrier demineralized bone matrix and block demineralized bone matrix. The results showed that bone marrow stem cells better adhered to microcarrier demineralized bone matrix and produced more extracellular matrices during in vitro culture. After in vivo implantation, microcarrier demineralized bone matrix seeded with bone marrow stem cells formed relatively more bone tissue than block demineralized bone matrix counterpart at three months upon histological examination. Furthermore, micro-computed tomography three-dimensional reconstruction showed that microcarrier demineralized bone matrix group regenerate significantly better and more bone tissues than block demineralized bone matrix both qualitatively and quantitatively (p < 0.05). Moreover, micro-computed tomography reconstructed angiographic images also demonstrated significantly enhanced tissue vascularization in microcarrier demineralized bone matrix group than in block demineralized bone matrix group both qualitatively and quantitatively (p < 0.05). Anti-CD31 immunohistochemical staining of (micro-) vessels and semi-quantitative analysis also evidenced enhanced vascularization of regenerated bone in microcarrier demineralized bone matrix group than in block demineralized bone matrix group (p < 0.05). In conclusion, the microcarrier form of demineralized bone matrix is an ideal bone regenerative scaffold due to its advantages of osteoinductivity and vascular induction, two essentials for in vivo bone regeneration.
体内植入细胞种子支架的新血管化不足仍然是工程骨形成临床转化的主要瓶颈。脱矿骨基质是骨工程的理想骨支架，因为其结构和生化成分与天然骨相似。我们假设脱矿骨基质的微载体形式有利于血管内生长和体内植入后的骨再生。在这项研究中，采用基于股血管蒂的骨工程大鼠模型，在硅胶室中填充脱矿骨基质支架，硅胶室环绕血管蒂，以比较微载体脱矿骨基质和块状脱矿骨基质在血管化骨再生效率方面的差异。结果表明，骨髓干细胞在体外培养时更好地黏附于微载体脱矿骨基质并产生更多的细胞外基质。体内植入后，组织学检查发现，骨髓干细胞接种在微载体脱矿骨基质上 3 个月后形成的骨组织比块状脱矿骨基质多。此外，微计算机断层扫描三维重建显示，微载体脱矿骨基质组在定性和定量两方面都比块状脱矿骨基质组再生更好、更多的骨组织（p<0.05）。而且，微计算机断层扫描重建血管造影图像也定性和定量地显示微载体脱矿骨基质组的组织血管化明显增强（p<0.05）。（微）血管的 CD31 免疫组化染色和半定量分析也证明了微载体脱矿骨基质组再生骨的血管化增强（p<0.05）。总之，由于具有成骨诱导和血管诱导的优势，脱矿骨基质的微载体形式是一种理想的骨再生支架，这是体内骨再生的两个必要条件。
