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.

A Series of Efficient Umbrella Modeling Strategies to Track Irradiation-Mutation Strains Improving Butyric Acid Production From the Pre-development Earlier Stage Point of View.

Clostridium tyrobutyricum (C. tyrobutyricum) is a fermentation strain used to produce butyric acid. A promising new biofuel, n-butanol, can be produced by catalysis of butyrate, which can be obtained through microbial fermentation. Butyric acid has various uses in food additives and flavor agents, antiseptic substances, drug formulations, and fragrances. Its use as a food flavoring has been approved by the European Union, and it has therefore been listed on the EU Lists of Flavorings. As butyric acid fermentation is a cost-efficient process, butyric acid is an attractive feedstock for various biofuels and food commercialization products. 12C6+ irradiation has advantages over conventional mutation methods for fermentation production due to its dosage conformity and excellent biological availability. Nevertheless, the effects of these heavy-ion irradiations on the specific productiveness of C. tyrobutyricum are still uncertain. We developed non-structured mathematical models to represent the heavy-ion irradiation of C. tyrobutyricum in biofermentation reactors. The kinetic models reflect various fermentation features of the mutants, including the mutant strain growth model, butyric acid formation model, and medium consumption model. The models were constructed based on the Markov chain Monte Carlo model and logistic regression. Models were verified using experimental data in response to different initial glucose concentrations (0-180 g/L). The parameters of fixed proposals are applied in the various fermentation stages. Predictions of these models were in accordance well with the results of fermentation assays. The maximum butyric acid production was 56.3 g/L. Our study provides reliable information for increasing butyric acid production and for evaluating the feasibility of using mutant strains of C. tyrobutyricum at the pre-development phase.

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.

Low Back Pain Caused by Iliopsoas Tendinopathy Treated with Ultrasound-Guided Local Injection of Anesthetic and Steroid: A Retrospective Study.

BACKGROUND: Low back pain is a prevalent symptom that occurs in all age of people, whereas the pathogenesis is unknown. Iliopsoas tendinopathy is an increasingly recognized hip disorder that may contribute to low back pain. Our purpose is to evaluate the effect of ultrasound-guided local injection of anesthetic and steroid into the trigger point of iliopsoas tendon in treating low back pain caused by iliopsoas tendinopathy. MATERIALS AND METHODS: This retrospective study reviewed 45 patients diagnosed with iliopsoas tendinopathy treated by B-ultrasound guided injection of 2 mL 2% lidocaine and 1 mL (5 mg) triamcinolone acetonide into the trigger point of iliopsoas tendon from March 2016 to June 2016. Medical records were collected to analyze the clinical presentation. Numerical Rating Scale (NRS) measuring low back pain and Harris Hip score (HHS) measuring hip pain and function were administered to determine patient outcomes. Telephone follow-up was conducted, and the mean follow-up was 11 months. RESULTS: We observed that most patients with iliopsoas tendinopathy also complain about chronic low back pain except for groin pain. After injection of anesthetic and corticosteroid into the iliopsoas tendon, the NRS of patients with low back pain fell from 7.68±1.31 to 2.58±1.16 immediately after the injection and 0.75±0.73 at follow-up. The HHS improved from 43.02±16.81 to 98.15±2.56 at follow-up. Statistically significant difference (P<0.001) was observed. All patients returned to their original level of function, and only five patients presented with mild low back pain at the follow-up. CONCLUSION: Low back pain is a prevalent presentation for iliopsoas tendinopathy. Diagnosis of iliopsoas tendinopathy should be considered in patients with low back pain with tenderness over the iliopsoas tendon. Ultrasound-guided local injection of anesthetic and steroid lead to satisfactory effect in relieving low back and groin pain and improving joint function.

Human ESC-sEVs alleviate age-related bone loss by rejuvenating senescent bone marrow-derived mesenchymal stem cells.

Tissue-resident stem cell senescence leads to stem cell exhaustion, which is a major cause of physiological and pathological ageing. Stem cell-derived extracellular vesicles (SC-EVs) have been reported in preclinical studies to possess therapeutic potential for diverse diseases. However, whether SC-EVs can rejuvenate senescent tissue stem cells to prevent age-related disorders still remains unknown. Here, we show that chronic application of human embryonic stem cell-derived small extracellular vesicles (hESC-sEVs) rescues the function of senescent bone marrow mesenchymal stem cells (BM-MSCs) and prevents age-related bone loss in ageing mice. Transcriptome analysis revealed that hESC-sEVs treatment upregulated the expression of genes involved in antiaging, stem cell proliferation and osteogenic differentiation in BM-MSCs. Furthermore, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis identified 4122 proteins encapsulated in hESC-sEVs. Bioinformatics analysis predicted that the protein components in the hESCs-sEVs function in a synergistic way to induce the activation of several canonical signalling pathways, including Wnt, Sirtuin, AMPK, PTEN signalling, which results in the upregulation of antiaging genes in BM-MSCs and then the recovery of senescent BM-MSCs function. Collectively, our findings reveal the effect of hESC-sEVs in reversing BM-MSCs senescence and age-related osteogenic dysfunction, thereby preventing age-related bone loss. Because hESC-sEVs could alleviate senescence of tissue-resident stem cells, they might be promising therapeutic candidates for age-related diseases.

[Mid-term effectiveness of surgical hip dislocation for femoroacetabular impingement].

OBJECTIVE: To assess the mid-term effecitveness of femoroacetabular impingement (FAI) treated by surgical hip dislocation. METHODS: Between April 2014 and August 2015, 15 patients (16 hips) with FAI were enrolled in the study and treated with surgical hip dislocation. There were 12 males and 3 females with an average age of 36.6 years (range, 22-59 years). Among them, 14 cases involved in unilateral hip and 1 in bilateral hips. The mean disease duration was 28 months (range, 4-120 months). Preoperative visual analogue scale (VAS) score and Harris hip score were 7.9±1.0 and 44.1±9.3, respectively. RESULTS: All incisions healed by first intention. There was no main complication, such as vessel and nerve injuries and infection. All 15 patients were followed up 30-46 months (mean, 39.5 months). The VAS score was 2.5±1.6 at 3 months and 0.5±0.7 at last follow-up. The Harris score was 85.5±4.4 at 3 months and 95.6±3.9 at last follow-up. There were significant differences in two scores between pre- and post-operation and between 3 months and last follow-up ( P<0.05). The satisfaction rate of hip function was 93.8% (15/16) at last follow-up. X-ray examination showed that there was no sign of impingment at the femoral head and neck and acetabulum forming site of the affected hip joint, and no complication such as loosening of internal fixator, nonunion of osteotomy, avascular necrosis of femoral head, and heterotopic ossification occurred during follow-up. CONCLUSION: The surgical hip dislocation is a safe and effective way to treat FAI in the mid-term follow-up, which can repair torn labrum and trim acetabulum and femoral neck.

High Body Mass Index is Related to Increased Perioperative Complications After Periacetabular Osteotomy.

The purpose of this study is to determine the relationship of body mass index (BMI), age, smoking status, and other comorbid conditions to the rate and type of complications occurring in the perioperative period following periacetabular osteotomy. A retrospective review was performed on 80 hips to determine demographic information as well as pre- and postoperative pain scores, center-edge angle, Tönnis angle, intraoperative blood loss, and perioperative complications within 90 days of surgery. Patients were placed into high- (>30) and low- (<30) BMI groups to determine any correlation between complications and BMI. The high-BMI group had a significantly greater rate of perioperative complications than the low-BMI group (30% vs 8%) and, correspondingly, patients with complications had significantly higher BMI than those without (30.9 ± 9.5, 26.2 ± 5.6) (P = .03). Center-edge angle and Tönnis angle were corrected in both groups. Improvement in postoperative pain scores and radiographically measured acetabular correction can be achieved in high- and low-BMI patients. High-BMI patients have a higher rate of perioperative wound complications.

[Mid-term effectiveness of arthroscopic surgery for femoroacetabular impingement].

Objective: To assess the mid-term effectiveness of arthroscopic surgery in treatment of femoroacetabular impingement (FAI). Methods: Between July 2014 and December 2015, 131 patients (132 hips) with FAI were enrolled in this study. There were 68 males and 63 females with an average age of 42.5 years (range, 17-68 years). The FAI was located at left hip in 72 cases, right hip in 58 cases, and bilateral hips in 1 case. The mean disease duration was 35 months (range, 3-120 months). Under arthroscopy, the femoral neck osteoplasty and/or acetabular rim trimming were performed, then the torn labrum was repaired. At the same time, the iliopsoas tendon was divided and the torn round ligament was debrided. The effectiveness was assessed by the visual analogue scale (VAS) and the Harris hip score (HHS). Results: After operation, the perineum nerve palsy and numbness of dorsal feet occurred in 2 cases and 3 cases, respectively. There was no other complication. All patients were followed up 20-36 months (mean, 27.7 months). There were significant differences in the VAS scores and HHS scores between pre-operation, post-operative 3 months, and the last follow-up ( P<0.05). Imaging examination showed that joint interspace of the involved hip was normal, and there was no sign of impingement and osteoarthritis in the femoral neck or acetabulum. Conclusion: Arthroscopic labral repair and osteoplasty is an effective and safe management for FAI in the mid-term follow-up.

Attitudes Toward Bile Extraction From Living Bears: Survey of Citizens and Students in Beijing.

Bear bile is a traditional Chinese medicine that has been used for millennia. Several arguments support and oppose the use of bear farming in terms of conservation and nonhuman animal welfare. This study involved designing a questionnaire and surveying a random sample of general citizens and college students in Beijing to elicit their attitudes on bile extraction from living bears. Older people and people with lower education levels used more bear bile medicines. In total, 29.47% (n = 204) of citizens and 23.14% (n = 81) of students surveyed used bear bile medicine since 1990. Students were less willing to use bear bile medicines than citizens (p < .05). The level the respondents agreed with the blue side (against the extraction of bile from living bears; anti for short) was significantly higher than that for the red side (support the extraction of bile from living bears; pro for short; p < .05). Additionally, college students had a more distinct attitude toward the opposing views, which indicates they were more inclined to oppose bile extraction from living bears.

Integration of stem cell-derived exosomes with in situ hydrogel glue as a promising tissue patch for articular cartilage regeneration.

The regeneration of articular cartilage, which scarcely shows innate self-healing ability, is a great challenge in clinical treatment. Stem cell-derived exosomes (SC-Exos), an important type of extracellular nanovesicle, exhibit great potential for cartilage regeneration to replace stem cell-based therapy. Cartilage regeneration often takes a relatively long time and there is currently no effective administration method to durably retain exosomes at cartilage defect sites to effectively exert their reparative effect. Therefore, in this study, we exploited a photoinduced imine crosslinking hydrogel glue, which presents excellent operation ability, biocompatibility and most importantly, cartilage-integration, as an exosome scaffold to prepare an acellular tissue patch (EHG) for cartilage regeneration. It was found that EHG can retain SC-Exos and positively regulate both chondrocytes and hBMSCs in vitro. Furthermore, EHG can integrate with native cartilage matrix and promote cell deposition at cartilage defect sites, finally resulting in the promotion of cartilage defect repair. The EHG tissue patch therefore provides a novel, cell-free scaffold material for wound repair.

Exosomes/tricalcium phosphate combination scaffolds can enhance bone regeneration by activating the PI3K/Akt signaling pathway.

BACKGROUND: Recently, accumulating evidence has shown that exosomes, the naturally secreted nanocarriers of cells, can exert therapeutic effects in various disease models in the absence of parent cells. However, application of exosomes in bone defect repair and regeneration has been rarely reported, and little is known regarding their underlying mechanisms. METHODS: Exosomes derived from human-induced pluripotent stem cell-derived mesenchymal stem cells (hiPS-MSC-Exos) were combined with tricalcium phosphate (ß-TCP) to repair critical-sized calvarial bone defects, and the efficacy was assessed by histological examination. We evaluated the in vitro effects of hiPSC-MSC-Exos on the proliferation, migration, and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) by cell-counting, scratch assays, and qRT-PCR, respectively. Gene expression profiling and bioinformatics analyses were also used to identify the underlying mechanisms in the repair. RESULTS: We found that the exosome/ß-TCP combination scaffolds could enhance osteogenesis as compared to pure ß-TCP scaffolds. In vitro assays showed that the exosomes could release from ß-TCP and could be internalized by hBMSCs. In addition, the internalization of exosomes into hBMSCs could profoundly enhance the proliferation, migration, and osteogenic differentiation of hBMSCs. Furthermore, gene expression profiling and bioinformatics analyses demonstrated that exosome/ß-TCP combination scaffolds significantly altered the expression of a network of genes involved in the PI3K/Akt signaling pathway. Functional studies further confirmed that the PI3K/Akt signaling pathway was the critical mediator during the exosome-induced osteogenic responses of hBMSCs. CONCLUSIONS: We propose that the exosomes can enhance the osteoinductivity of ß-TCP through activating the PI3K/Akt signaling pathway of hBMSCs, which means that the exosome/ß-TCP combination scaffolds possess better osteogenesis activity than pure ß-TCP scaffolds. These results indicate that naturally secreted nanocarriers-exosomes can be used as a bioactive material to improve the bioactivity of the biomaterials, and that hiPS-MSC-Exos combined with ß-TCP scaffolds can be potentially used for repairing bone defects.

Dimethyloxaloylglycine Promotes the Angiogenic Activity of Mesenchymal Stem Cells Derived from iPSCs via Activation of the PI3K/Akt Pathway for Bone Regeneration.

The vascularization of tissue-engineered bone is a prerequisite step for the successful repair of bone defects. Hypoxia inducible factor-1α (HIF-1α) plays an essential role in angiogenesis-osteogenesis coupling during bone regeneration and can activate the expression of angiogenic factors in mesenchymal stem cells (MSCs). Dimethyloxaloylglycine (DMOG) is an angiogenic small molecule that can inhibit prolyl hydroxylase (PHD) enzymes and thus regulate the stability of HIF-1α in cells at normal oxygen tension. Human induced pluripotent stem cell-derived MSCs (hiPSC-MSCs) are promising alternatives for stem cell therapy. In this study, we evaluated the effect of DMOG on promoting hiPSC-MSCs angiogenesis in tissue-engineered bone and simultaneously explored the underlying mechanisms in vitro. The effectiveness of DMOG in improving the expression of HIF-1α and its downstream angiogenic genes in hiPSC-MSCs demonstrated that DMOG significantly enhanced the gene and protein expression profiles of angiogenic-related factors in hiPSC-MSCs by sustaining the expression of HIF-1α. Further analysis showed that DMOG-stimulated hiPSC-MSCs angiogenesis was associated with the phosphorylation of protein kinase B (Akt) and with an increase in VEGF production. The effects could be blocked by the addition of the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. In a critical-sized calvarial defect model in rats, DMOG-treated hiPSC-MSCs showed markedly improved angiogenic capacity in the tissue-engineered bone, leading to bone regeneration. Collectively, the results indicate that DMOG, via activation of the PI3K/Akt pathway, promotes the angiogenesis of hiPSC-MSCs in tissue-engineered bone for bone defect repair and that DMOG-treated hiPSC-MSCs can be exploited as a potential therapeutic tool in bone regeneration.

Bioactive borate glass promotes the repair of radius segmental bone defects by enhancing the osteogenic differentiation of BMSCs.

Bioactive borate glass (BG) has emerged as a promising alternative for bone regeneration due to its high osteoinductivity, osteoconductivity, compressive strength, and biocompatibility. However, the role of BG in large segmental bone repair is unclear and little is known about the underlying mechanism of BG's osteoinductivity. In this study, we demonstrated that BG possessed pro-osteogenic effects in an experimental model of critical-sized radius defects. Transplanting BG to radius defects resulted in better repair of bone defects as compared to widely used ß-TCP. Histological and morphological analysis indicated that BG significantly enhanced new bone formation. Furthermore, the degradation rate of the BG was faster than that of ß-TCP, which matched the higher bone regeneration rate. In addition, ions from BG enhanced cell viability, ALP activity, and osteogenic-related genes expression. Mechanistically, the critical genes Smad1/5 and Dlx5 in the BMP pathway and p-Smad1/5 proteins were significantly elevated after BG transplantation, and these effects could be blocked by the BMP/Smad specific inhibitor. Taken together, our findings suggest that BG could repair large segmental bone defects through activating the BMP/Smad pathway and osteogenic differentiation in BMSCs.

Exosomes released from human induced pluripotent stem cells-derived MSCs facilitate cutaneous wound healing by promoting collagen synthesis and angiogenesis.

BACKGROUND: Human induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs) have emerged as a promising alternative for stem cell transplantation therapy. Exosomes derived from mesenchymal stem cells (MSC-Exos) can play important roles in repairing injured tissues. However, to date, no reports have demonstrated the use of hiPSC-MSC-Exos in cutaneous wound healing, and little is known regarding their underlying mechanisms in tissue repair. METHODS: hiPSC-MSC-Exos were injected subcutaneously around wound sites in a rat model and the efficacy of hiPSC-MSC-Exos was assessed by measuring wound closure areas, by histological and immunofluorescence examinations. We also evaluated the in vitro effects of hiPSC-MSC-Exos on both the proliferation and migration of human dermal fibroblasts and human umbilical vein endothelial cells (HUVECs) by cell-counting and scratch assays, respectively. The effects of exosomes on fibroblast collagen and elastin secretion were studied in enzyme-linked immunosorbent assays and quantitative reverse-transcriptase-polymerase chain reaction (qRT-PCR). In vitro capillary network formation was determined in tube-formation assays. RESULTS: Transplanting hiPSC-MSC-Exos to wound sites resulted in accelerated re-epithelialization, reduced scar widths, and the promotion of collagen maturity. Moreover, hiPSC-MSC-Exos not only promoted the generation of newly formed vessels, but also accelerated their maturation in wound sites. We found that hiPSC-MSC-Exos stimulated the proliferation and migration of human dermal fibroblasts and HUVECs in a dose-dependent manner in vitro. Similarly, Type I, III collagen and elastin secretion and mRNA expression by fibroblasts and tube formation by HUVECs were also increased with increasing hiPSC-MSC-Exos concentrations. CONCLUSIONS: Our findings suggest that hiPSC-MSC-Exos can facilitate cutaneous wound healing by promoting collagen synthesis and angiogenesis. These data provide the first evidence for the potential of hiPSC-MSC-Exos in treating cutaneous wounds.

Gentamicin-loaded borate bioactive glass eradicates osteomyelitis due to Escherichia coli in a rabbit model.

The treatment of osteomyelitis induced by Gram-negative bacilli is rarely reported in the literature. This study established a rabbit tibia model of osteomyelitis induced by the Gram-negative bacillus Escherichia coli. Using this model, pellets composed of a chitosan-bonded mixture of borate bioactive glass and gentamicin were evaluated in vitro and in vivo for the treatment of osteomyelitis induced by Escherichia coli. Our results showed that the pellets in phosphate-buffered saline released gentamicin continuously over 26 days. Without the simultaneous use of a systemic antibiotic, the implantation of the gentamicin-loaded pellets into the osteomyelitis region of the tibia resulted in the eradication of 81.82% of infections, as determined by microbiological, histological and radiographic evaluation, and supported the ingrowth of new bone into the tibia defects after 6 weeks of implantation. The results indicate that the gentamicin-loaded borate bioactive glass implant, combining sustained drug release with the ability to support new bone formation, could provide a method for treating osteomyelitis induced by Gram-negative bacilli.

Down-regulation of programmed cell death 5 by insulin-like growth factor 1 in osteoarthritis chondrocytes.

PURPOSE: The aim of this study was to investigate the expression of insulin-like growth factor (IGF)-1 and programmed cell death 5 (PDCD5) in osteoarthritis chondrocytes, and to explore the potential correlation between them in the apoptosis process of osteoarthritis chondrocytes. METHODS: Patients with knee osteoarthritis were placed into four categories according to radiological staging. The mRNA and protein levels of IGF-1 and PDCD5 in osteoarthritis chondrocytes were respectively detected by quantitative reverse transcriptase polymerase chain reaction (qPCR) and western blotting. In addition, IGF-1 and PDCD5 protein expression in chondrocytes were also measured by immunohistochemistry. Apoptotic cells were measured by TUNEL staining. RESULTS: Both the mRNA and protein levels of IGF-1 were down-regulated, while the levels of PDCD5 were up-regulated, and the mRNA and protein levels of IGF-1 were negatively correlated with those of PDCD5, respectively. The apoptotic cell was significantly increased in osteoarthritis chondrocytes compared with control. Importantly, the apoptosis rate was positively correlated with PDCD5 protein expression and negatively correlated with IGF-1 protein expression CONCLUSIONS: We concluded that IGF-1 may down-regulate the expression of PDCD5 and thus inhibit the apoptosis of osteoarthritis chondrocytes.

[Vancomycin-loaded bioactive borate glass for treatment of chronic osteomyelitis in rabbits].

OBJECTIVE: Bioactive borate glass (BG) has good biocompatibility and biodegradation. To investigate the feasibility of bioactive borate glass as a carrier of the antibiotic controlled-releasing by implanting vancomycin-loaded BG (VBG) into the focus of tibia chronic osteomyelitis after debridement. METHODS: VBG and vancomycin-loaded calcium sulfate (VCS) were prepared with a vancomycin content of 80 mg/g. Sixty-five New Zealand white rabbits, weighing 2.12-3.91 kg (mean, 2.65 kg), were used. The tibia chronic osteomyelitis rabbit models were established by injecting methicillin-resistant Staphylococcus aureus (MRSA, 0.1 mL, 1 x 10(9) cfu/mL) into the right tibia of 65 rabbits. After 3 weeks of injection, 54 rabbits of successful models were randomly divided into groups A (n=11), B (n=11), C (n=16), and D (n=16). Simple debridement was performed in group A; BG, VCS, and VBG were implanted into the infection sites of groups B, C, and D respectively after thorough debridement. A sample of the debrided tissues was harvested for bacterial examination. The vancomycin serum levels were determined in groups C and D at 1, 2, 4, 10, 24, and 48 hours after operation. The boron serum levels were determined in groups B and D at 10, 24, 48, 72, and 120 hours after operation. After 8 weeks, the effectiveness was assessed radiographically, bacteriologically, and histopathologically. RESULTS: Ten rabbits died after operation. No vancomycin was detected in group C; the vancomycin level increased gradually, reached the highest level at 4 hours after operation, and then decreased rapidly in group D. No boron was detected in group B; the boron reached the highest serum level at 10 hours after operation, and then decreased gradually in group D. At 8 weeks, calcium sulfate degraded in group C; BG degraded partially in group D; and no obvious degradation was observed in group B. The repair effect was better in group D than in group C. There was no significant difference in radiograph scoring between groups A, B, C and D (P > 0.05) before operation, but there was significant difference between group D and groups A, B, C (P < 0.05) at 8 weeks after operation. The bacterial culture showed that all the MRSA results were positive in 4 groups. At 8 weeks, the negative rates of MRSA examination were 36.36%, 18.18%, 73.33%, and 81.25% respectively in groups A, B, C, and D, showing significant differences between group D and groups A, B (P < 0.05). The histopathological observation showed that a large number of new bones formed and no foreign body reaction occurred in group D. The histopathologic scores of groups A, B, C, and D were 6.45 +/- 3.62, 7.55 +/- 3.36, 4.27 +/- 2.91, and 3.81 +/- 3.04 respectively, showing significant differences between group D and groups A, B, and between group C and group B (P < 0.05). CONCLUSION: VBG can improve the repair of bone defect in the treatment of chronic osteomyelitis.