People have been looking for tissue engineering approaches to treat large segment bone defects as replacements of autologous bone method. Cell-seeded scaffolds are promising candidates, but lack of vascularization into the scaffolds has greatly hindered their applications. To address this problem, we used a co-culture of bone marrow derived mesenchymal stem cells (BMSCs) and endothelial progenitor cells (EPCs) on calcium phosphate ceramics scaffolds for better vascularization and thus osteogenesis. Different ratios of BMSC/EPC (3:1, 2:1, 1:1, 1:2, 1:3) in the co-culture were examined in vitro, and it was revealed that the optimal value for neovascularization and osteogenesis was 1:3 and 2:1, respectively. Then cell mixtures with the optimized ratios were cultured in distinct regions of volume-reduced scaffolds and allowed to culture for 7 days for sufficient cell adhesion and ingrowth, as demonstrated by cell proliferation throughout the scaffolds and enhanced expressions of cell markers and growth factors comparing to a mono-culture of BMSCs. Upon implantation into a rabbit large segmental bone defect model, the scaffolds with co-culture of the cells had better osteoid tissue formation and bone remodeling supported by neovascularization, comparing to scaffolds with mono-culture or without cells. Yet with sub-optimal efficacy comparing to autologous bone grafts, it was believed to be a promising candidate for treatment of large segment bone defects.

中文翻译：

---

骨髓间充质干细胞和内皮祖细胞共培养可增强大段骨缺损修复。

人们一直在寻找组织工程方法来治疗大段骨缺损，以替代自体骨方法。细胞接种的支架是有前途的候选者，但是支架中缺乏血管化已经极大地阻碍了它们的应用。为了解决这个问题，我们在磷酸钙陶瓷支架上使用了骨髓来源的间充质干细胞（BMSCs）和内皮祖细胞（EPCs）的共培养物，以更好地血管化和成骨。在体外培养中检查了不同比例的BMSC / EPC（3：1、2：1、1：1、1：2、1：3），并且发现新血管形成和成骨的最佳值分别为1：3和2：1。然后将具有最佳比例的细胞混合物培养在体积减少的支架的不同区域中，并允许培养7天，以确保足够的细胞粘附和向内生长，这通过整个支架的细胞增殖以及与之相比增强的细胞标志物和生长因子的表达来证明。 BMSC的单一培养物。与单培养或无细胞的支架相比，植入兔大节段性骨缺损模型后，与细胞共培养的支架具有更好的类骨组织形成和新血管形成支持的骨重塑。然而，与自体骨移植相比，其功效欠佳，