Extracellular vesicles from bone marrow-derived multipotent mesenchymal stromal cells regulate inflammation and enhance tendon healing

来自骨髓多能间充质基质细胞的细胞外囊泡调节炎症并增强肌腱愈合

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作者:Zhengzhou Shi, Qi Wang, Dapeng Jiang

Background

Extracellular vesicles from bone marrow-derived multipotent mesenchymal stromal cells (BMSC-EVs) can play important roles in the repair of injured tissues. However, no reports have investigated the role and underlying mechanisms of BMSCs-EVs in the tendon repair process. We hypothesized that BMSC-EVs may play a role in modulating inflammation during tendon healing and improving tendon repair in a rat model of patellar tendon injury.

Conclusions

Overall, our findings show that the local administration of BMSC-EVs promotes tendon healing by suppressing inflammation and apoptotic cell accumulation and increasing the proportion of tendon-resident stem/progenitor cells. These findings provide a basis for the potential clinical use of BMSC-EVs in tendon repair.

Methods

First, we created window defects in the patellar tendons of Sprague-Dawley rats. Rats (n = 16) were then randomly assigned to three groups: BMSC-EVs group, Fibrin group, and control group. Rats in the BMSC-EVs group were treated with BMSC-EVs and fibrin glue (25 µg in 10 µL). Rats in the fibrin group were treated with fibrin only, and those in the control group received no treatment. Histopathology, immunohistochemistry, and gene expression analyses were performed at 2 and 4 weeks after surgery.

Results

At 4 weeks, tendons treated with BMSC-EVs showed regularly aligned and compact collagen fibers as compared with the disrupted scar-like healing in rats in the fibrin and control groups. The expression of genes related to tendon matrix formation and tenogenic differentiation: collagen (COL)-1a1, scleraxis (SCX), and tenomodulin (TNMD) was significantly higher in the BMSC-EVs group than in the other two groups. With histopathology, we observed significantly higher numbers of CD146+ tendon stem cells and fewer numbers of apoptotic cells and C-C chemokine receptor type 7 (CCR7)-positive proinflammatory macrophages in the BMSC-EVs group. BMSC-EVs treatment also led to an increase in the expression of anti-inflammatory mediators (IL-10 and IL-4) at 2 weeks after surgery. Conclusions: Overall, our findings show that the local administration of BMSC-EVs promotes tendon healing by suppressing inflammation and apoptotic cell accumulation and increasing the proportion of tendon-resident stem/progenitor cells. These findings provide a basis for the potential clinical use of BMSC-EVs in tendon repair.

文献解析

1. 文献背景信息​

  • ​标题/作者/期刊/年份​​:

    Shi Z, Wang Q, Jiang D. Journal of Translational Medicine(2019, IF=6.1)

    ​权威性​​:中科院医学2区期刊,聚焦转化医学研究;​​时效性​​:2019年发表,仍属近年研究,但需结合后续进展评估。

  • ​研究领域与背景​​:

    属于​​肌腱修复与细胞外囊泡(EVs)治疗​​领域。当前争议:传统肌腱修复易形成瘢痕组织,功能恢复差;间充质基质细胞(MSCs)的疗效机制(直接分化 vs. 旁分泌作用)尚不明确。

  • ​研究动机​​:

    填补空白:首次探索BMSC-EVs在肌腱修复中的作用,明确其通过调控炎症和干细胞增殖促进愈合的机制,避免MSCs移植的潜在风险(如畸胎瘤)。


​2. 研究问题与假设​

  • ​核心问题​​:BMSC-EVs能否通过调节炎症和干细胞活性促进肌腱再生?

  • ​假设​​:BMSC-EVs局部注射可抑制炎症(如减少CCR7+巨噬细胞)、减少凋亡、增加肌腱干细胞(CD146+)比例,从而改善胶原排列和功能恢复。


​3. 研究方法学与技术路线​

  • ​实验设计​​:

    大鼠髌腱损伤模型(n=16),随机分为BMSC-EVs组(EVs+纤维蛋白胶)、纤维蛋白胶组、空白对照组。

  • ​关键技术​​:

    • ​EVs分离​​:超速离心法(未提及具体表征指标如粒径、标志蛋白)。

    • ​评估方法​​:组织学(胶原排列)、免疫组化(CD146、CCR7)、qPCR(COL1A1、SCX、TNMD)。

  • ​创新方法​​:

    首次将BMSC-EVs与纤维蛋白胶联合局部递送,优化靶向性;但缺乏EVs亚型分析(如外泌体vs.微囊泡)。


​4. 结果与数据解析​

  • ​主要发现​​:

    • ​功能恢复​​:BMSC-EVs组4周时胶原排列更规则(vs. 对照组瘢痕样结构)。

    • ​分子机制​​:

      • 促修复基因(COL1A1、SCX、TNMD)表达显著上调(p值未明确);

      • CD146+肌腱干细胞数量↑,凋亡细胞和CCR7+巨噬细胞↓;

      • 抗炎因子(IL-10、IL-4)在2周时表达增加。

  • ​数据验证​​:

    通过多时间点(2/4周)和多维度(组织+分子)数据交叉验证,但缺乏独立动物队列或体外功能实验(如肌腱力学测试)。

  • ​局限性​​:

    样本量小(n=16/3组),未分析EVs具体活性成分(如miRNA或蛋白质组)。


​5. 讨论与机制阐释​

  • ​机制深度​​:

    提出BMSC-EVs通过“免疫调节-干细胞激活-基质重塑”轴促进修复,但未明确关键效应分子(如特定miRNA)。

  • ​与既往研究对比​​:

    支持MSCs旁分泌作用主导的观点(Lee et al. 2018),但反驳了“干细胞分化主导修复”的传统假说。

  • ​未解决问题​​:

    EVs的最佳剂量、给药频率,以及临床转化中规模化生产的挑战。


​6. 创新点与学术贡献​

  • ​理论创新​​:

    首次证明BMSC-EVs可替代MSCs用于肌腱修复,强调免疫微环境调控的重要性。

  • ​技术贡献​​:

    局部递送策略(EVs+纤维蛋白胶)可推广至其他软组织损伤模型。

  • ​实际价值​​:

    为无细胞疗法提供依据,规避MSCs应用的伦理和安全问题,潜在应用于运动员肌腱病或术后粘连预防。


​总结​​:该研究为肌腱修复提供了新思路,但需进一步验证EVs的作用成分和临床前大动物实验。未来可结合单细胞测序解析EVs对肌腱微环境的精准调控。

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