Bone & Joint Research最新文献

Aims: Osteoarthritis (OA) is a chronic and debilitating joint disease. Despite its prevalence, especially in ageing and obese populations, effective treatments targeting the molecular mechanisms of OA are limited. This study aimed to investigate the role of carpaine (CP), a major alkaloid from the Carica papaya leaf, in inhibiting articular cartilage destruction and synovitis during OA progression, and to elucidate the underlying molecular mechanisms.

Methods: CP (purity > 98%) was dissolved in dimethyl sulfoxide (DMSO). Various antibodies and reagents were sourced from Sigma-Aldrich, Abcam, and other suppliers. Peritoneal macrophages (pMACs) were cultured in Dulbecco's Modified Eagle Medium (DMEM) and treated with CP to assess its effects on inflammatory cytokine production and nuclear factor-kappa B (NF-κB) signalling. A total of 40 ten-week-old male C57/BL6 mice underwent destabilization of the medial meniscus (DMM) surgery to induce OA. Post-surgery, mice were treated with CP (0.5 or 3 mg/kg) or vehicle via intra-articular injections for up to ten weeks. Cartilage degradation and synovitis were evaluated using Safranin O, Fast Green staining, haematoxylin and eosin (H&E) staining, immunohistochemistry, and quantitative polymerase chain reaction (PCR).

Results: CP treatment significantly reduced cartilage degeneration and maintained hyaline cartilage thickness compared to the vehicle group. Indicators of cartilage degeneration, such as collagen X (Col X) and matrix metallopeptidase 13 (MMP13), were markedly decreased in the CP-treated group. CP-treated mice exhibited significantly lower synovitis scores at both five and ten weeks post-DMM surgery. CP prominently decreased the production of proinflammatory cytokines (interleukin (IL)-1β, IL-6) in M1 polarized macrophages both in vitro and in vivo. CP impeded NF-κB signalling by promoting p65 degradation through the E3 ubiquitin ligase LRSAM1. The defensive effect of CP was reversed by Lrsam1 small interfering RNA (siRNA), confirming the role of LRSAM1 in CP-mediated NF-κB inhibition.

Conclusion: CP acts as a 'physiological brake' on NF-κB activation, thereby mitigating synovial inflammation and cartilage destruction in OA. These findings suggest that targeting synovitis via CP could be a promising therapeutic strategy for OA.

Aims: Fracture nonunion represents a major complication in orthopaedic surgery, occurring in 5% to 10% of fracture patients. Fracture nonunions are associated with pain and loss of function, and lead to a substantial socioeconomic burden. The present retrospective cohort study analyzed direct and indirect costs and length of hospital stay, number of surgical procedures, and hospital (re-)admissions of nonunion patients.

Methods: Data from 18- to 65-year-old patients surgically treated for lower limb fractures and nonunions in a German level I trauma centre between 2012 and 2018 were analyzed. A total of 193 patients with nonunion were included, and 2,511 patients with fractures served as the control group. Direct costs were calculated using reimbursement according to the diagnosis-related group (DRG). Indirect costs were calculated including daily sickness allowance and productivity loss.

Results: The median healing time of nonunion patients was 45 weeks. Treatment expenses showed a 2.6-fold increase in direct costs, a 3.3-fold increase in indirect costs, and a 3.3-fold increase in total costs for nonunion patients compared to the control group. As every patient with a nonunion suffered from a fracture prior to nonunion treatment, costs were calculated by adding the median direct costs of €10,487 (IQR 9,173 to 15,262), median daily sickness allowance of €23,046 (IQR 14,892 to 36,264), median productivity loss of €85,714 (IQR 60,949 to 126,650), and median total socioeconomic burden of €123,334 (IQR 88,630 to 176,329).

Conclusion: Nonunions not only pose a significant burden on the injured individual and on healthcare systems, but also have a substantial socioeconomic impact. High direct and indirect costs illustrate that healing complications need to be detected and addressed as early as possible.

Aims: Sufficient primary implant stability with minimal bone damage is one of the challenges for uncemented implant fixation to prevent periprosthetic fractures and implant loosening. A pilot study on a non-viscoelastic material (polyurethane foam) showed a reduced impaction force when using vibratory implant insertion. This study assessed the effectiveness of vibratory implant insertion compared to an established implant insertion method in physiological viscoelastic bone from porcine hips.

Methods: Acetabular components were impacted line-to-line and into 1 mm nominal undersized cavities in porcine acetabula (n = 24 in total, n = 6 acetabula per group of study) using vibration (60 Hz) and 1 Hz (established) impaction methods. The impaction force, remaining polar gap, and lever-out moment were measured and compared between the impaction methods and different press-fits.

Results: The vibratory impaction method produced almost 40% lower impaction forces at both press-fit levels. However, complete seating at the nominal press-fit of 1 mm was not achieved, and primary stability was lower for the vibratory impaction for either press-fit.

Conclusion: Bone fracture risk due to high impaction forces could be reduced by vibrational implant insertion at the cost of a reduction in primary stability. The outcome of the vibratory impaction method in porcine bone was similar to a previous study using polyurethane foams, suggesting that the viscoelasticity of bone may not play a crucial role during press-fit implant impaction.

Aims: To evaluate the role of autophagy in primary knee fibroblasts undergoing myofibroblast differentiation as an in vitro model of arthrofibrosis, a complication after total knee arthroplasty characterized by aberrant intra-articular scar tissue formation and limited range of motion.

Methods: We conducted a therapeutic screen of autophagic-modulating therapies in primary human knee fibroblasts undergoing transforming growth factor-beta 1 (TGF-β1)-mediated myofibroblast differentiation. Autophagy was induced pharmacologically with rapamycin or by amino acid deprivation. Picrosirius red staining was performed to quantify collagen deposition. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were conducted to evaluate fibrotic gene expression levels.

Results: Rapamycin, an mTOR complex 1 (mTORC1) inhibitor and autophagy inducer, reduced TGF-β1-mediated collagen deposition. Interestingly, we simultaneously report that myofibrogenic genes, including ACTA2, were highly upregulated following rapamycin-TGF-β1 treatment. When autophagy was induced through amino acid deprivation, we demonstrated suppressed extracellular matrix levels, fibrotic gene expression (e.g. ACTA2), and SMAD2 phosphorylation levels in TGF-β1-stimulated fibroblasts.

Conclusion: Our findings demonstrate that the induction of cellular autophagy suppresses TGF-β1-induced collagen deposition in primary human knee fibroblasts. Taken together, these data suggest that cellular autophagy may be prophylactic against the pathogenesis of arthrofibrosis.

Aims: Meniscus injury can lead to knee synovitis and cartilage deterioration, ultimately resulting in osteoarthritis (OA). Mitochondrial dysfunction has been identified as an induction factor in OA development, owing to an imbalance between the production of reactive oxygen species (ROS) and the antioxidant capacity of cells. However, the contribution of mitochondrial function in the meniscus to OA remains unclear. The purpose of this work was to elucidate the impact of HNGF6A, a mitochondrial-derived protective peptide, on meniscus senescence and degeneration to clarify the underlying mechanisms of ROS-induced OA pathogenesis.

Methods: Primary human meniscus cells were subjected to oxidative stress using tert-butyl hydrogen peroxide (TBHP). Mitochondrial function and ROS levels were evaluated using transmission electron microscopy (TEM), cytometry, and immunofluorescence. C57BL/6 mice subjected to destabilization of the medial meniscus (DMM) were either administered or not administered HNGF6A, and gait analysis was performed at eight weeks after surgery. Knee joints were collected for graft micro-CT and histological staining.

Results: Mitochondrial function was found to be impaired in the degraded menisci in OA. Pretreatment with HNGF6A significantly restored the matrix degradation and cell apoptosis induced by TBHP, and maintained mitochondrial redox homeostasis, which corresponded with the activation of autophagy and FUN14 domain containing 1 (FUNDC1) upon HNGF6A treatment. The animal studies also revealed that HNGF6A alleviates meniscus degeneration and osteophyte volume, and ameliorates the OA phenotype in vivo.

Conclusion: HNGF6A was found to protect meniscus cells by restoring FUNDC1-mediated mitochondrial redox homeostasis and autophagy. Thus, HNGF6A may have therapeutic applications in the prevention and treatment of meniscal degeneration and OA progression.

Aims: This study aimed to examine the differences in bone induction and osseointegration performance of acellular extracellular matrix bone at different sites.

Methods: We decellularized bone from bovine epiphysis near the marrow cavity (NMC), the middle of the cancellous bone (MCB), and near the cartilage (NC). The characterization, physicochemical properties, and effectiveness of the decellularization process of decellularized extracellular matrix (dECM) were analyzed. The proliferation, adhesion, seeding efficiency, and osteogenic differentiation properties of bone marrow mesenchymal stem cells (BMSCs) on decellularized extracellular matrix were investigated. The osteogenicity and osteointegration of dECM from different sources were verified in vivo by animal experiments, and the compatibility of dECM in vivo was also verified.

Results: The NC group had the most significant compressive properties, where the compressive strength was about 1.62 times higher than that of the MCB group (p = 0.022) and 1.34 times higher than that of the NMC group (p < 0.001). dECM scaffolds had good histocompatibility and supported the adhesion and proliferation of BMSCs. In vitro, compared with the remaining two groups, the MCB group significantly upregulated the expression of osteogenic genes (alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), osteopontin (OPN), collagen type 1 (COL1), and bone morphogenetic protein 2 (BMP2)) and marker proteins (ALP, BMP2), whereas the NC group showed the weakest osteoinductive properties. In vivo, we confirmed that the MCB group possessed the most significant osteogenic and osseointegrative properties, followed by the NMC group, and the NC group proved to be the weakest. In particular, the MCB group possessed the ability to endogenously immunomodulate macrophage M1 phenotype to M2 phenotype polarization, creating the most favourable immune microenvironment for osteogenesis.

Conclusion: Our data indicated that the xenogenic dECM scaffolds in MCB position possess the most significant biocompatibility and in vitro and in vivo induced osteogenesis and osseointegration properties. This study provides a more complete basis for the selection of dECM scaffolds in bone defect repair. In future studies of dECM composites applied to bone tissue engineering (BTE), utilizing the middle part of cancellous bone may be the best solution.

Aims: Tibial cortex transverse transport (TTT) represents an innovative surgical technique used in managing lower limb ischaemic conditions, focusing specifically on diabetic foot ulcers. This study aimed to assess the safety of TTT by evaluating the stress magnitude and distribution on the tibia and tibial osteotomy blocks.

Methods: A 3D finite element model was developed to simulate the TTT system, including the tibia, osteotomy blocks, skin, and TTT device. The models were reconstructed using Mimics, Geomagic, and SolidWorks, and analyzed with Ansys finite element processing software. To estimate the fracture risk under specific conditions, we calculated the stress limits and distribution the tibia could withstand without fracturing under various loading scenarios, such as torsion and axial compression.

Results: The results indicate that stress on the tibial cortex increased progressively with the advancement of bone transport fixation adjustment, and was primarily concentrated around the pinholes used to lift the osteotomy block. No significant differences were observed between the control and TTT groups.

Conclusion: Through finite element analysis, it was determined that TTT does not compromise the overall stability of the tibia, and the TTT device provides protection against bone fracture caused by window-cutting in diabetic patients. Therefore, to preserve the TTT system's stability, its components must be protected from high-impact forces.

Aims: Circulating biochemistry markers are commonly used to monitor and detect disease-induced dysfunctions including osteoarthritis (OA). However, the causal nature of this relationship is nevertheless largely unknown, due to unmeasured confounding factors from observational studies. We aimed to reveal the causal relationship between 28 circulating biochemistry markers and OA pathogenesis.

Methods: We conducted a comprehensive bidirectional two-sample Mendelian randomization (MR) study between 28 circulating biomarkers and six OA types, using large-scale genome-wide association study (GWAS) summary statistics data from a UK Biobank cohort (n = 450,243) and the latest OA meta-analysis (n = 826,690). We replicated the significant results of low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) in an independent large GWAS dataset obtained from the Global Lipids Genetics Consortium (GLGC) (n > 800,000).

Results: Using 73 to 792 instrumental variables for biomarkers, this large MR analysis identified 11 causal associations at the Bonferroni corrected significance level of 2.98 × 10^-4, involving seven biomarkers and five OA types. LDL-C (odds ratio (OR) per SD increase 0.90, 95% CI 0.86 to 0.93), apolipoprotein B (OR 0.86, 95% CI 0.82 to 0.91), TC (OR 0.90, 95% CI 0.86 to 0.94), calcium (OR 0.82, 95% CI 0.75 to 0.90), and glucose (OR 0.81, 95% CI 0.73 to 0.89) are causally associated with a reduced risk of OA, while phosphate (OR 1.18, 95% CI 1.08 to 1.30) and aspartate aminotransferase (OR 1.15, 95% CI 1.07 to 1.24) are causally associated with an increased risk. Analysis of GLGC summary statistics successfully replicated LDL-C (OR 0.93, 95% CI 0.90 to 0.96) and TC (OR 0.92, 95% CI 0.89 to 0.95).

Conclusion: This comprehensive bidirectional MR analysis provides new insights into the prevention and treatment of OA, as well as understanding the biological mechanism underlying OA pathogenesis.

Aims: The aim of the present research was to analyze the effects of different sterilization methods and storage times on the mechanical properties (load at first break, strain at first break, maximum load, strain at maximum load, and Young's modulus of elasticity) of different allografts compared to native groups.

Methods: Two types of grafts were harvested from human cadavers: 165 tibialis anterior (TA) and 166 peroneus longus (PL) tendons. According to the two types of sterilization methods (γ and electron beam irradiation) or the lack of one, and the six types of storage time (one to six months), 36 groups were created. In addition, we created a 1 to 1 native group, which was not sterilized and stored, tested within four hours of collection.

Results: In the results of tendon type TA compared to TA native group, we observed significant differences at the fifth month of storage for all measured parameters. Load at first break of the frozen values at the fifth month was significantly inferior to the native group (p = 0.034). For strain at first break and strain at maximum load, all sterilization methods were significantly inferior at the fifth month (p = 0.003 to p = 0.009). Maximum load values were significantly superior with E-beam irradiation at the fifth month (p = 0.003), and also significantly higher with γ irradiation at the fifth month (p = 0.009). Young's modulus showed significantly inferior values in the frozen tendons at the fifth month (p = 0.001 to p = 0.003). In tendon type PL, no significant differences were found for any of the tested parameters compared to the native group.

Conclusion: Our results indicate that freezing alters mechanical properties via the decrease seen in the ultimate tensile strength. In addition, at the fifth and sixth months of storage, time could notably affect allografts rather than the sterilization procedures.

Aims: Osteoarthritis (OA) is a common degenerative disease that leads to pain, disability, and reduced quality of life. Orientin exhibits considerable anti-inflammatory and antioxidative properties, but its role in chondrocyte senescence and OA progress has not yet been fully characterized. The aim of this study was to evaluate the protective effects of orientin on OA.

Methods: The role of orientin in extracellular matrix (ECM) degradation, mitochondrial homeostasis, and chondrocyte senescence was investigated in vitro. Meanwhile, we used molecular docking, small molecular inhibitors, and RNA interference to screen and validate candidate proteins regulated by orientin. In an anterior cruciate ligament transection (ACLT) rat model, radiograph, micro-CT, and various histological examinations were applied to evaluate the therapeutic effects of orientin on OA.

Results: We found that orientin inhibited ECM degradation and senescence-associated secretory phenotype (SASP) factor expression in interleukin (IL)-1β-treated chondrocytes. Additionally, orientin reduced the level of reactive oxygen species (ROS) and improved mitochondrial homeostasis. Furthermore, orientin suppressed IL-1β-induced activation of the nuclear factor kappa B (NF-κB) signalling pathway. We also found that orientin bound to phosphoinositide 3-kinase (PI3K) and inhibited NF-κB cascades via the PI3K/AKT pathway. In vivo, we demonstrated that orientin improved cartilage wear and reduced synovial inflammation and osteophyte in an ACLT rat model.

Conclusion: Orientin improves mitochondrial homeostasis, inhibits chondrocyte senescence, and alleviates OA progress via the PI3K/AKT/NF-κB axis, which suggests that orientin is a potential effective therapeutic agent for OA.