Background/objectives

Accelerating the process of bone regeneration is of great interest for surgeons and basic scientists alike. Recently, umbilical cord mesenchymal stem cells (UCMSCs) are considered clinically applicable for tissue regeneration due to their noninvasive harvesting and better viability. Nonetheless, the bone regenerative ability of human UCMSCs (HUCMSCs) is largely unknown. This study aimed to investigate whether Wnt10b-overexpressing HUCMSCs have enhanced bone regeneration ability in a rat model.

Method

A rat calvarial defect was performed on 8-week old male Sprague Dawley rats. Commercially purchased HUCMSCs^Emp in hydrogel, HUCMSCs^Wnt10b in hydrogel and HUCMSCs^Wnt10b with IWR-1 were placed in the calvarial bone defect right after surgery on rats (N = 8 rats for each group). Calvaria were harvested for micro-CT analysis and histology four weeks after surgery. CFU-F and multi-differentiation assay by oil red staining, alizarin red staining and RT-PCR (real-time polymerase chain reaction) were performed on HUCMSCs^Emp and HUCMSCs^Wnt10b in vitro. Conditioned media from HUCMSCs^Emp and HUCMSCs^Wnt10b were collected and used to treat human umbilical cord vein endothelial cells in Matrigel to access vessel formation capacity by tube formation assay.

Results

Alizarin red staining, oil red staining and RT-PCR results showed robust osteogenic differentiation but poor adipogenic differentiation ability of HUCMSCs^Wnt10b. Furthermore, HUCMSCs^Wnt10b could accelerate bone defect healing, which was likely due to enhanced angiogenesis after the HUCMSCs^Wnt10b treatment, because more CD31+ vessels and increased vascular endothelial growth factor-A (VEGF-A) expression were observed, compared with the HUCMSCs^Emp treatment. Conditioned media from HUCMSCs^Wnt10b also induced endothelial cells to form vessel tubes in a tube formation assay, which could be abolished by SU5416, an angiogenesis inhibitor.

Conclusion

To our knowledge, this is the first study providing empirical evidence that HUCMSCs^Wnt10b can enhance their ability to heal calvarial bone defects via VEGF-mediated angiogenesis.

The translational potential of this article

HUCMSCs^Wnt10b can accelerate critical size calvaria and are a new promising therapeutic cell source for fracture nonunion healing.

中文翻译：

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过表达 Wnt10b 的脐带间充质干细胞通过增强成骨和 VEGF 介导的血管生成促进临界大小的大鼠颅骨缺损愈合。

背景/目标

外科医生和基础科学家都对加速骨再生过程非常感兴趣。最近，脐带间充质干细胞 (UCMSCs) 因其无创采集和更好的活力而被认为在临床上适用于组织再生。尽管如此，人类 UCMSCs (HUCMSCs) 的骨再生能力在很大程度上是未知的。本研究旨在调查 Wnt10b 过表达的 HUCMSCs 在大鼠模型中是否具有增强的骨再生能力。

方法

对 8 周龄雄性 Sprague Dawley 大鼠进行大鼠颅骨缺损。商业购买的水凝胶中的HUCMSCs ^Emp、水凝胶中的HUCMSCs ^Wnt10b和带有IWR-1的HUCMSCs ^Wnt10b在大鼠手术后立即置于颅骨缺损处（ 每组N = 8只大鼠）。手术后 4 周采集颅骨进行微 CT 分析和组织学分析。在体外对HUCMSCs ^Emp和HUCMSCs ^Wnt10b 进行CFU-F和油红染色、茜素红染色和RT-PCR（实时聚合酶链反应）的多分化测定。来自 HUCMSCs ^Emp和 HUCMSCs ^{Wnt10b的条件培养基}收集并用于处理Matrigel中的人脐带静脉内皮细胞，以通过管形成测定获得血管形成能力。

结果

^{茜素红染色、油红染色和RT-PCR结果显示HUCMSCs Wnt10b}的成骨分化能力强但成脂分化能力差。此外，HUCMSCs ^Wnt10b可以加速骨缺损愈合，这可能是由于 HUCMSCs ^{Wnt10b治疗后血管生成增强，因为与 HUCMSCs Emp}治疗相比，观察到更多的 CD31+ 血管和增加的血管内皮生长因子-A (VEGF-A) 表达. 来自 HUCMSCs ^Wnt10b的条件培养基还在管形成试验中诱导内皮细胞形成血管管，这可以被血管生成抑制剂 SU5416 消除。

结论

据我们所知，这是第一项提供经验证据的研究，证明 HUCMSCs ^Wnt10b可以通过 VEGF 介导的血管生成增强其治愈颅骨缺损的能力。

本文的翻译潜力

HUCMSCs ^Wnt10b可以加速临界大小的颅盖骨，是一种新的有前途的骨折不愈合治疗细胞来源。