Large extracellular vesicles secreted by human iPSC-derived MSCs ameliorate tendinopathy via regulating macrophage heterogeneity.

Tendinopathy is a common musculoskeletal disorder which results in chronic pain and reduced performance. The therapeutic effect of stem cell derived-small extracellular vesicles (sEVs) for tendinopathy has been validated in recent years. However, whether large extracellular vesicles (lEVs), another subset of extracellular vesicles, possesses the ability for the improvement of tendinopathy remains unknown. Here, we showed that lEVs secreted from iPSC-derived MSCs (iMSC-lEVs) significantly mitigated pain derived from tendinopathy in rats. Immunohistochemical analysis showed that iMSC-lEVs regulated the heterogeneity of infiltrated macrophages and several inflammatory cytokines in rat tendon tissue. Meanwhile, in vitro experiments revealed that the M1 pro-inflammatory macrophages were repolarized towards M2 anti-inflammatory macrophages by iMSC-lEVs, and this effect was mediated by regulating p38 MAPK pathway. Moreover, liquid chromatography-tandem mass spectrometry analysis identified 2208 proteins encapsulated in iMSC-lEVs, including 134 new-found proteins beyond current Vesiclepedia database. By bioinformatics and Western blot analyses, we showed that DUSP2 and DUSP3, the negative regulator of p38 phosphorylation, were enriched in iMSC-lEVs and could be transported to macrophages. Further, the immunomodulatory effect of iMSC-lEVs on macrophages was validated in explant tendon tissue from tendinopathy patients. Taken together, our results demonstrate that iMSC-lEVs could reduce inflammation in tendinopathy by regulating macrophage heterogeneity, which is mediated via the p38 MAPK pathway by delivery of DUSP2 and DUSP3, and might be a promising candidate for tendinopathy therapy.

The Therapeutic Effect of iMSC-Derived Small Extracellular Vesicles on Tendinopathy Related Pain Through Alleviating Inflammation: An in vivo and in vitro Study.

Background: Tendinopathy is a common cause of tendon pain. However, there is a lack of effective therapies for managing tendinopathy pain, despite the pain being the most common complaint of patients. This study aimed to evaluate the therapeutic effect of small extracellular vesicles released from induced pluripotent stem cell-derived mesenchymal stem cells (iMSC-sEVs) on tendinopathy pain and explore the underlying mechanisms. Methods: Rat tendinopathy model was established and underwent the injection of iMSC-sEVs to the quadriceps tendon one week after modeling. Pain-related behaviors were measured for the following four weeks. Tendon histology was assessed four weeks after the injection. To further investigate the potential mechanism, tenocytes were stimulated with IL-1ß to mimic tendinopathy in vitro. The effect of iMSC-sEVs on tenocyte proliferation and the expression of proinflammatory cytokines were measured by CCK-8, RT-qPCR, and ELISA. RNA-seq was further performed to systematically analyze the related global changes and underlying mechanisms. Results: Local injection of iMSC-sEVs was effective in alleviating pain in the tendinopathy rats compared with the vehicle group. Tendon histology showed ameliorated tendinopathy characteristics. Upon iMSC-sEVs treatment, significantly increased tenocyte proliferation and less expression of proinflammatory cytokines were observed. Transcriptome analysis revealed that iMSC-sEVs treatment upregulated the expression of genes involved in cell proliferation and downregulated the expression of genes involved in inflammation and collagen degeneration. Conclusion: Collectively, this study demonstrated iMSC-sEVs protect tenocytes from inflammatory stimulation and promote cell proliferation as well as collagen synthesis, thereby relieving pain derived from tendinopathy. As a cell-free regenerative treatment, iMSC-sEVs might be a promising therapeutic candidate for tendinopathy.

Small extracellular vesicles from iPSC-derived mesenchymal stem cells ameliorate tendinopathy pain by inhibiting mast cell activation.

Aim: This study aimed to explore the effect of small extracellular vesicles from induced pluripotent stem cell-derived mesenchymal stem cells (iMSC-sEVs) on acute pain and investigate the underlying mechanisms. Materials & methods: The pathology of tendons was accessed by hematoxylin and eosin staining, immunohistochemical and immunofluorescent staining. The pain degree was measured by pain-related behaviors. In vitro, we performed ß-hexosaminidase release assay, RT-qPCR, toluidine blue staining, ELISA and RNA sequencing. Results: iMSC-sEVs effectively alleviated acute pain in tendinopathy as well as inhibiting activated mast cell infiltration and interactions with nerve fibers in vivo. In vitro, iMSC-sEVs reduced the degranulation of mast cells and the expression of proinflammatory cytokines and genes involved in the HIF-1 signaling pathway. Conclusion: This study demonstrated that iMSC-sEVs relieved tendinopathy-related pain through inhibiting mast cell activation via the HIF-1 signaling pathway.

[Mid-term effectiveness of periacetabular osteotomy through modified ilioinguinal approach for acetabular dysplasia in adults].

OBJECTIVE: To investigate the mid-term effectiveness of periacetabular osteotomy (PAO) through modified ilioinguinal approach for acetabular dysplasia in adults. METHODS: Between January 2016 and December 2018, 39 patients (43 hips) with acetabular dysplasia who met the selection criteria were enrolled in the study and their clinical data were retrospectively analyzed. All patients were treated with PAO via modified ilioinguinal approach (firstly, the skin and superficial facia were cut via the traditional ilioinguinal approach, and the deep tissues were cut via the modified iliac-femoral approach). There were 3 males (3 hips) and 36 females (40 hips) with an average age of 36 years (range, 18-51 years). Among them, 35 cases of lesions involved single hip and 4 cases of lesions involved bilateral hips. The disease duration ranged from 4 to 96 months, with a median of 18 months. According to the modified Tönnis grading for osteoarthritis, 35 hips were classified as grade 0, 6 hips as grade Ⅰ, and 2 hips as grade Ⅱ. All patients had different degrees of hip pain. The preoperative visual analogue scale (VAS) score of pain was 4.7±0.8, and the modified Harris hip score was 78.5±8.6. The lateral centre-edge angle (LCEA) was (10.52±10.83)°, and the acetabular index (AI) was (26.89±9.07) °. The operation time, intraoperative blood loss, and the incidence of complications were recorded. LCEA, AI, and the progression of osteoarthritis were reviewed by X-ray films. The function and pain of hip joint were evaluated by modified Harris hip score and VAS score. RESULTS: All operations were successfully completed. The operation time was 90-150 minutes, with an average of 130 minutes. The volume of intraoperative blood loss was 350-600 mL, with an average of 500.6 mL. All patients were followed up 17-52 months, with an average of 32.7 months. Postoperative numbness of the lateral femoral cutaneous nerve occurred in 3 cases, and no other complications occurred. At last follow-up, the modified Harris hip score was 97.7±3.7 and VAS score was 0.9±1.1, both of which were better than those before operation ( P<0.05). At 1 year after operation, X-ray films showed that the all osteotomies healed. In term of the modified Tönnis grading for osteoarthritis, 1 hip downgraded from grade 1 to grade 0, while the remaining hips stayed unchanged. At last follow-up, LCEA and AI were (27.54±8.49) ° and (11.30±5.53) °, respectively, which were significantly different from those before operation ( P<0.05). CONCLUSION: PAO through modified ilioinguinal approach is effective in relieving pain and restoring hip function in adults with acetabular dysplasia, which can overcome the disadvantages of the traditional ilioinguinal approach, and may delay the development of osteoarthritis.

Controlled release of MSC-derived small extracellular vesicles by an injectable Diels-Alder crosslinked hyaluronic acid/PEG hydrogel for osteoarthritis improvement.

Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) show great therapeutic potential for osteoarthritis (OA). However, their low bioavailability through intraarticular injection inhibits the process of clinical application. In the present study, an injectable Diels-Alder crosslinked hyaluronic acid/PEG (DAHP) hydrogel was developed as an intraarticular delivery platform for MSC-sEVs. Our results showed that the DAHP hydrogel could be prepared easily and that its gelation properties were suitable for intraarticular administration. In vitro studies demonstrated that the DAHP hydrogel could achieve sustained release of MSC-sEVs mainly by degradation control and preserve the therapeutic functions of sEVs. An in vivo experiment revealed that the DAHP hydrogel could enhance the efficacy of MSC-sEVs for OA improvement. This study provides a suitable delivery platform for MSC-sEVs-based OA therapy. STATEMENT OF SIGNIFICANCE: Mesenchymal stem cell (MSC)-derived small extracellular vesicles (MSC-sEVs) have shown a high potential as a cell-free therapeutic factor for treating osteoarthritis (OA). The sustained release of these MSC-sEVs in the joint space is essential for their clinical application. Herein, an injectable Diels-Alder crosslinked hyaluronic acid/PEG (DAHP) hydrogel was developed for intraarticular release of MSC-sEVs. The properties of the DAHP hydrogel, namely gelation features, cytocompatibility, sustained release, and functional maintenance of MSC-sEVs, make it suitable for intraarticular injection and delivery of sEVs. The efficacy of MSC-sEVs was enhanced by the intraarticularly injected DAHP hydrogel. Our present study provides a promising sustained delivery platform for MSC-sEVs for treating OA.