Aseptic loosening of orthopedic implants is an inflammatory disease characterized by immune cell activation, chronic inflammation, and destruction of periprosthetic bone, and is one of the leading reasons for prosthetic failure, affecting 12% of total joint arthroplasty patients. Matrix-bound nanovesicles (MBVs) are a subclass of extracellular vesicle recently shown to mitigate inflammation in preclinical models of rheumatoid arthritis and influenza-mediated “cytokine storm.” The molecular mechanism of these anti-inflammatory properties is only partially understood. The objective of the present study was to investigate the effects of MBV on RANKL-induced osteoclast formation in vitro and particulate-induced osteolysis in vivo. Results showed that MBV attenuated osteoclast differentiation and activity by suppressing the NF-κB signaling pathway and downstream NFATc1, DC-STAMP, c-Src, and cathepsin K expression. In vivo, local administration of MBV attenuated ultrahigh molecular weight polyethylene particle-induced osteolysis, bone reconstruction, and periosteal inflammation. The results suggest that MBV may be a therapeutic option for preventing periprosthetic loosening.
Abstract We examined whether physical activity (PA) explains the association between dietary inflammatory potential and osteoarthritis (OA) in the elderly. A total of 1249 elderly people (≥65 years) were eligible for this study from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2016. The semi-quantitative Food Frequency Questionnaire (FFQ) and Global PA Questionnaire (GPAQ) were used to evaluate the diet and PA of the elderly, respectively. The multivariable logistic regression model estimated the odds ratio (OR) and 95% confidence interval (CI) between Energy-adjusted Dietary Inflammatory Index (E-DII) and OA. The interaction of E-DII and PA on depressive events was tested, and the mediation analysis of PA was performed. The average E-DII in this study was +0.68 (SE 0.08), and the score ranges from -5.32 (most anti-inflammatory) to +4.26 (most pro-inflammatory). In comparison with the first quartile, the elderly from the second quartile (OR: 1.16 [95% CI: 1.06, 1.68]) to the fourth quartile (OR: 1.64 [95% CI: 1.13, 2.37]) had a higher risk of OA before adjustment for PA. An interaction was observed between E-DII and PA in terms of the risk of OA ( P Interaction < 0.001). The whole related part was mediated by PA (20.08%). Our findings indicated that the higher pro-inflammatory potential of diet was associated with a higher risk of OA, and low PA was an important part of the mediating factor in the relationship between systemic low-grade dietary inflammation and the risk of OA.
Abstract Background: Wear particle-induced periprosthetic osteolysis is a common long-term complication of total joint arthroplasty, and represents the major cause of aseptic loosening and subsequent implant failure. Currently, there are no effective therapeutic options to prevent osteolysis from occurring and often need revision surgery. Exosomes are important nano-sized paracrine mediators of intercellular communications and can be directly utilized as therapeutic agents for tissue repair and regeneration. Here, we explored the therapeutic potential of exosomes from human urine-derived stem cells (USC-Exos) in preventing wear particle-induced osteolysis. Methods: USCs were characterized by flow cytometry and multiple differentiation potential. USC-Exos were identified by transmission electron microscopy (TEM), dynamic light scattering (DLS) and western blotting (WB). The impact of USC-Exos on osteoblastic differentiation of bone marrow mesenchymal stromal cells (BMSCs) and osteoclastogenesis of RAW264.7 cells were verified in vitro . The effects of USC-Exos on ultra high molecular weight PE (UHMWPE)-induced murine calvarial osteolysis model were tested to evaluate bone mass, inflammation, osteogenic and osteoclastic activities. Results: USCs were positive for CD44, CD73, CD29 and CD90, but negative for CD34 and CD45. USCs were able to differentiate into osteogenic, chondrogenic, and adipogenic cells. USC-Exos exhibited a round-shaped morphology with a double-layered membrane structure and positive for CD63 and TSG101, negative for Calnexin. In vitro , USC-Exos could promote the osteogenic differentiation of BMSCs, reduces the production of proinflammatory factors in macrophages and suppresses their osteoclastic abilities. In vivo , injection of USC-Exos into the center of the calvariae caused less inflammatory cytokine generation and less osteolysis compared to control and significantly enhanced the bone formation. Conclusions: Our findings demonstrate that USC-Exos can prevent UHMWPE-induced osteolysis by inciting less inflammatory, inhibiting bone resorption and stimulating bone formation. USC-Exos may represent a potential natural agent for the treatment of periprosthetic osteolysis and to obtain therapeutic exosomes for osteolytic treatment, aseptic loosening patients may just need to collect a certain volume of their own urine to harvest USCs and USC-Exos.
Abstract Osteoarthritis (OA) is a degenerative joint disease which lacks effective medical treatment due to ill‐defined molecular mechanisms underlying the pathology. Inflammation is a key factor that induces and aggravates OA. Therefore, the current study aims to explore roles of the dysregulated long non‐coding RNAs in the pro‐inflammatory cytokine IL‐1β‐mediated catabolic effects in cartilage tissue and chondrocytes. We identified RP11‐364P22.2 as dysregulated in OA patient‐derived cartilage tissues and highly responsive to IL‐1β stimulus. RNA pull‐down coupled with mass spectrometry demonstrated that RP11‐364P22.2 physically binds to activating transcription factor 3 (ATF3) and thus increases the protein stability and facilitates its nuclear translocation. Loss‐ and gain‐of‐function assays indicated that the interaction between RP11‐364P22.2 and ATF3 is indispensable for the detrimental effects of IL‐1β including growth inhibition, apoptosis induction as well as degradation of the key chondrocyte structural proteins of type II collage and Aggrecan and synthesis of the extracellular matrix‐degrading enzyme MMP13 in chondrocytes. In vivo, depletion of the RP11‐364P22.2 effector ATF3 drastically prevented OA development in the rats with surgical destabilization of the medial meniscus (DMM). These results highlight the important roles of lncRNAs in the pathogenesis of OA and indicate the RP11‐364P22.2/ATF3 regulatory axis as a potential therapeutic target of inflammation‐induced OA.
Osteoarthritis (OA) is a degenerative joint disease characterized by articular cartilage degradation. Dysregulated autophagy is a major cause of OA. However, the underlying mechanism is unclear. Here, we found that the expression of element-binding protein (CREB) was downregulated in both cartilage tissues of OA patients and mouse OA model. In tert-butyl hydroperoxide solution-treated chondrocytes, increased apoptosis and autophagic blockage were attenuated by CREB overexpression. Mechanically, MiR-373 directly targeted the 3′UTR of methyltransferase-like 3 (METTL3) and led to its downregulation. METTL3 epigenetically suppressed TFEB. The upregulation of miR-373 by CREB overexpression induced the release of TFEB from METTL3 and restored the autophagy activity of chondrocytes. Taken together, our study showed that CREB alleviates OA injury through regulating the expression of miR-373, which directly targeted METTL3, and finally relieved TFEB from METTL3-mediated epigenetic suppression. The CREB/miR-373/METTL3/TFEB axis may be used as a potential target for the treatment of OA.
Whether antibiotics should be included remains greatly debated in Masquelet technique. This study intended to determine the effect of polymethyl methacrylate (PMMA) spacer loaded with different vancomycin concentrations on bone defect repair. Hollow cylindrical spacers consisting of PMMA and varying vancomycin concentrations (0, 1, 2, 4, 6, 8, and 10 g) were prepared. Critical bone defects of rabbits were created at the radial shaft, and spacers were implanted and subsequently intramedullary fixed with retrograde Kirschner's wires (n = 4 for each vancomycin concentration). After 4 weeks, the induced membranes were opened and cancellous allografts were implanted into the defects. Eight weeks post-operatively, the results of X-ray, histology, and micro-CT revealed that some cortical bone was formed to bridge the gap and the bone marrow cavity was formed over time. Quantitatively, there was more new bone formation in the groups with a relatively lower vancomycin concentration (1-4 g) compared with that in the groups with a higher vancomycin concentration (6-10 g). Our findings suggested that PMMA spacers loaded with relatively lower vancomycin concentrations (1-4 g) did not interfere with new bone formation, whereas spacers loaded with relatively higher vancomycin concentrations (6-10 g) had negative effects on bone formation.
Wear debris particle-induced periprosthetic osteolysis is a severe complication of total joint replacement that results in aseptic loosening and subsequent arthroplasty failure. No effective therapeutic agents or drugs have been approved to prevent or treat osteolysis; thus, revision surgery is often needed. Extracellular vesicles (EVs) are vital nanosized regulators of intercellular communication that can be directly applied to promote tissue repair and regeneration. In this study, we assessed the therapeutic potential of EVs from human urine-derived stem cells (USCs) (USC-EVs) in preventing ultrahigh-molecular-weight polyethylene (UHMWPE) particle-induced osteolysis.USCs were characterized by measuring induced multipotent differentiation and flow cytometry. USC-EVs were isolated and characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS) and Western blotting. RAW264.7 cells and bone marrow mesenchymal stem cells (BMSCs) were cultured with USC-EVs to verify osteoclast differentiation and osteoblast formation, respectively, in vitro. The effects of USC-EVs were investigated on a UHMWPE particle-induced murine calvarial osteolysis model by assessing bone mass, the inflammatory reaction, and osteoblast and osteoclast formation.USCs differentiated into osteogenic, adipogenic and chondrogenic cells in vitro and were positive for CD44, CD73, CD29 and CD90 but negative for CD34 and CD45. USC-EVs exhibited a cup-like morphology with a double-layered membrane structure and were positive for CD63 and TSG101 and negative for calnexin. In vitro, USC-EVs promoted the osteogenic differentiation of BMSCs and reduced proinflammatory factor production and osteoclastic activity in RAW264.7 cells. In vivo, local injection of USC-EVs around the central sites of the calvaria decreased inflammatory cytokine generation and osteolysis compared with the control groups and significantly increased bone formation.Based on our findings, USC-EVs prevent UHMWPE particle-induced osteolysis by decreasing inflammation, suppressing bone resorption and promoting bone formation.
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