Aims

This study intended to investigate the effect of vericiguat (VIT) on titanium rod osseointegration in aged rats with iron overload, and also explore the role of VIT in osteoblast and osteoclast differentiation.

The interleukin-6/gp130-associated Janus Kinases/STAT3 axis is known to play an important role in mediating inflammatory signals, resulting in production of matrix metalloproteinase-3 (MMP-3). The hip joints with rapidly destructive coxopathy (RDC) demonstrate rapid chondrolysis, probably by increased production of MMP-3 observed in the early stage of RDC. In the recent study, no apparent activation of STAT3 has been shown in the synovial tissues obtained from the osteoarthritic joint at operation. However, no data are currently available on STAT3 activation in the synovial tissues in the early stage of RDC. This study aimed to elucidate STAT3 activation in the synovial tissues in the early stage of RDC. Synovial tissues within 7 months from the disease onset were obtained from four RDC patients with femoral head destruction and high serum levels of MMP-3. RDC synovial tissues showed the synovial lining hyperplasia with an increase of CD68-positive macrophages and CD3-positive T lymphocytes. STAT3 phosphorylation was found in the synovial tissues by immunohistochemistry using anti-phospho-STAT3 antibody. The majority of phospho-STAT3-positive cells were the synovial lining cells and exhibited negative expression of macrophage or T cell marker. Treatment with tofacitinib, a Janus Kinase inhibitor, resulted in a decrease in phospho-STAT3-positive cells, especially with high intensity, indicating effective suppression of STAT3 activation in RDC synovial tissues. Inhibitory effect of tofacitinib could act through the Janus Kinase/STAT3 axis in the synovial tissues in the early stage of RDC. Therefore, STAT3 may be a potential therapeutic target for prevention of joint structural damage in RDC. Acknowledgements: This study was supported by Katakami Foundation for Clinical Research

Aim. Diagnosis of periprosthetic shoulder infections (PSI) is difficult as they are mostly caused by low-virulent bacteria and patients do not show typical infection signs, such as elevated blood markers, wound leakage, or red and swollen skin. Ultrasound-guided biopsies for culture may therefore be an alternative for mini-open biopsies as less costly and invasive method. The aim of this study was to determine the diagnostic value and reliability of ultrasound-guided biopsies for cultures alone and in combination polymerase chain reaction (PCR), and/or synovial markers for preoperative diagnosis of PSI in patients undergoing revision shoulder surgery. Method. A prospective explorative diagnostic cohort study was performed including patients undergoing revision shoulder replacement surgery. A shoulder puncture was taken preoperatively before incision to collect synovial fluid for interleukin-6 (IL-6), calprotectin, WBC, polymorphonuclear cells determination. Prior to revision surgery, six ultrasound-guided synovial tissue biopsies were collected for culture and two additional for PCR analysis. Six routine care tissue biopsies were taken during revision surgery and served as reference standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV; primary outcome measure), and accuracy were calculated for ultrasound-guided biopsies, and synovial markers, and combinations of these. Results. Fifty-five patients were included. In 24 patients, routine tissue cultures were positive for infection. Cultures from ultrasound-guided biopsies diagnosed an infection in 7 of these patients, yielding a sensitivity, specificity, PPV, NPV, and accuracy of 29.2%, 93.5%, 77.8%, 63.0%, and 65.6%, respectively. Ultrasound-guided biopsies in combination with synovial WBC increased the NPV to 76.7% and accuracy to 73.8%. When synovial WBC and calprotectin were combined with ultrasound-guided biopsies, it resulted in a better diagnostic value: sensitivity 69.2%, specificity 80.0%, PPV 69.2%, NPV 80.0%, and accuracy 75.8%. Ultrasound-guided biopsies in combination with calprotectin and ESR yielded a sensitivity of 50.0%, specificity of 93.8%, PPV of 80.0%, NPV of 78.9%, and accuracy of 79.2%. Synovial fluid was obtained in 42 patients. Sensitivities of WBC, PMN, IL-6, and calprotectin were between 25.0% and 35.7%, specificities between 89.5% and 95.0%, PPVs between 60.0% and 83.3%, NPVs between 65.4% and 69.4%, and accuracies between 64.5% and 70.6%. Conclusions. In this prospective study we showed that ultrasound-guided biopsies for cultures alone and in combination with PCR and/or synovial markers are not reliable enough to use in clinical practice for the preoperative diagnosis of low grade PSI

Abstract. Cranial cruciate ligament (CrCL) disease/rupture is a highly prevalent orthopaedic disease in dogs and common cause of pain, lameness, and secondary joint osteoarthritis (OA). Previous experiments investigating the role of glutamate receptors (GluR) in arthritic degeneration and pain revealed that OA biomarkers assessing early bone turnover and inflammation, including osteoprotegerin (OPG) and the receptor activator of nuclear factor kappa-B ligand (RANKL) are more likely to be influenced by glutamate signalling. Moreover, interleukin-6 (IL-6) has a complex and potentially bi directional (beneficial and detrimental) effect, and it is a critical mediator of arthritic pain, OA progression and joint destruction. Objectives. 1) to recruit dogs undergoing CrCL disease/rupture surgery and obtain discarded synovial fluid (SF) and serum/plasma (ethics approval, RCVS:2017/14/Alves); 2) to quantify the biomarkers listed above in the SF and serum/plasma by enzyme linked immunosorbent assay (ELISA); 3) to assess radiographic OA at the time of surgery and correlate it with the biomarkers and clinical findings. Methods. Abnova, Abcam and AMSBIO ELISA kits were tested using a validation protocol relating the standard curve to a dilution series of SF and serum/plasma (1× to 1/50×), with and without SF hyaluronidase treatment to evaluate linearity, specificity and optimal dilutions. Validated ELISA kits were used to measure [IL-6], glutamate [glu], [RANKL] and [OPG] in SF and serum/plasma. For each dog, CrCL disease pre-operative lameness scores were graded as: (1) mild, (2) moderate (easily visible), (3) marked (encumbered), (4) non-weightbearing lameness. Blinded OA scoring was performed on radiographs [15–60, normal-severe OA]. Results. canine population (n=14) was of various breeds, aged between 2–10 years and weighing 17.1–45.5Kg; 42.86% male; 57.14% female; 83.33% males and 62.5% females were neutered. Lameness scores varied from 1 and 4 (average 2.07±1.12) and radiographic OA scores from 18 and 36 (average 27.86±5.11). Individual correlations in concentrations with respect to age, weight, lameness score (1–4) and OA scores (15–60) were tested. SF [glu] and lameness score were inversely correlated with higher levels of lameness corresponding to lower SF [glu] (P=0.0141). SF [RANKL] inversely correlated with weight (P=0.0045) and lameness score (P=0.0135), and serum [RANKL] inversely correlated with weight (P=0.0437). There was also a negative correlation between SF and serum [OPG] and weight (P=0.0165 and P=0.0208, respectively). No other significant correlations were detected. Overall, [glu] and [IL-6] are increased in SF compared to serum/plasma, by 12.84 and 1.28, respectively, whereas all the remaining biomarkers are higher (2–3 times) in the serum/plasma compared to SF. Principal component analysis (PCA) and Pearson correlation coefficient matrix [IL-6/glu/RANKL/OPG] (n=7) showed SF [IL-6] correlates with SF [glu] (rs=0.64) and strong positive correlations between SF/serum [RANKL] and SF/serum [OPG] (rs 0.68–0.96). Conclusions. Dogs with CrCL disease show an association between the bone remodelling markers RANKL and OPG, and the inflammatory cytokine IL-6, and to a lesser extent SF [glu]. Therapeutics targeting bone remodelling, IL-6 or GluR/[glu] may be of interest for the management of OA in dogs. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Aims

Impaired fracture repair in patients with type 2 diabetes mellitus (T2DM) is not fully understood. In this study, we aimed to characterize the local changes in gene expression (GE) associated with diabetic fracture. We used an unbiased approach to compare GE in the fracture callus of Zucker diabetic fatty (ZDF) rats relative to wild-type (WT) littermates at three weeks following femoral osteotomy.

Aims

The management of periprosthetic joint infection (PJI) remains a major challenge in orthopaedic surgery. In this study, we aimed to characterize the local bone microstructure and metabolism in a clinical cohort of patients with chronic PJI.

Total hip replacement (THR) is indicated for patients with osteoarthritis where conservative treatment has failed. Metal alloys used in THR implants such as cobalt-chromium (CoCr) have been known to cause pro-inflammatory reactions in patients, therefore leading to the need for costly revision surgery. This study therefore aimed to investigate the role of TLR4 in the activation of a human osteoblast model in response to CoCr particles in vitro. Human osteoblasts (MG-63 cell line) were seeded at a density of 100,000 cells and treated with 0.5, 5, 50mm3 CoCr particles per cell for 24-hours. Trypan blue and the XTT Cell Proliferation Kit II were then used in conjunction with the cells to assess CoCr-induced cytotoxicity. Cells were pre-treated with a commercially available TLR4-specific small molecule inhibitor (CLI-095) for 6 hours. Untreated cells were used as a negative control and lipopolysaccharide (LPS) was used as a positive control. Following treatment the cell supernatant was collected and used for enzyme-linked immunosorbant assay (ELISA) to measure the secretion of interleukin-8 (IL-8), CXCL10, and interleukin-6 (IL-6). Trypan blue and XTT analysis showed that there was no significant changes to cell viability or proliferation at any dose used of CoCr after 24 hours. There was a significant increase in protein secretion of IL-8 (p<0.001), CXCL10 (p<0.001), and IL-6 (p<0.001) in the cells which received the highest dosage of CoCr. This pro-inflammatory secretory response was ameliorated by TLR4 blockade (p<0.001). CoCr particles are not cytotoxic to osteoblasts but they do induce pro-inflammatory changes as characterised by increased secretion of chemokines IL-8, CXCL10, and IL-6. These responses occur via a TLR4-mediated pathway and upon inhibition they can be effectively ameliorated. This is particularly important as TLR4 could be a potential target for pharmacological intervention used in patients experiencing immunological reactions to metal implant debris

Senescent chondrocyte and subchondral osteoclast overburden aggravate inflammatory cytokine and pro-catabolic proteinase overproduction, accelerating extracellular matrix degradation and pain during osteoarthritis (OA). Fibronectin type III domain containing 5 (FNDC5) is found to promote tissue homeostasis and alleviate inflammation. This study aimed to characterize what role Fndc5 may play in chondrocyte aging and OA development.

Serum and macroscopically healthy and osteoarthritic cartilage were biopsied from patients with knee OA who received total knee replacement. Murine chondrocytes were transfected with Fndc5 RNAi or cDNA. Mice overexpressing Fndc5 (Fndc5Tg) were operated to have destabilized medial meniscus mediated (DMM) joint injury as an experimental OA model. Cellular senescence was characterized using RT-PCR analysis of p16INK4A, p21CIP1, and p53 expression together with ß-galactosidase activity staining. Articular cartilage damage and synovitis were graded using OARSI scores. Osteophyte formation and mechanical allodynia were quantified using microCT imaging and von Frey filament, respectively. Osteoclast formation was examined using tartrate-resistant acid phosphatase staining.

Senescent chondrocyte and subchondral osteoclast overburden together with decreased serum FNDC5 levels were present in human osteoarthritic cartilage. Fndc5 knockdown upregulated senescence program together with increased IL-6, MMP9 and Adamts5 expression, whereas Alcian blue-stained glycosaminoglycan production were inhibited. Forced Fndc5 expression repressed senescence, apoptosis and IL-6 expression, reversing proliferation and extracellular matrix production in inflamed chondrocytes. Fndc5Tg mice showed few OA signs, including articular cartilage erosion, synovitis, osteophyte formation, subchondral plate sclerosis and mechanical allodynia together with decreased IL-6 production and few senescent chondrocytes and subchondral osteoclast formation during DMM-induced joint injury. Mechanistically, Fndc5 reversed histone H3K27me3-mediated IL-6 transcription repression to reduce reactive oxygen species production.

Fndc5 loss correlated with OA development. It was indispensable in chondrocyte growth and anabolism. This study sheds light onto the anti-ageing and anti-inflammatory actions of Fndc5 to chondrocytes; and highlights the chondroprotective function of Fndc5 to compromise OA.

Mesenchymal stem cells (MSC) have potent immunomodulatory and regenerative effects via soluble factors. One approach to improve stem cell-based therapies is encapsulation of MSC in hydrogels based on natural proteins such as collagen and fibrin, which play critical roles in bone healing. In this work, we comparatively studied the influence of collagen and fibrin hydrogels of varying stiffness on the paracrine interactions established by MSC with macrophages and osteoblasts. Type I collagen and fibrin hydrogels in a similar stiffness range loaded with MSC from donants were prepared by modifying the protein concentration. Viability and morphology of MSC in hydrogels as well as cell migration rate from the matrices were determined. Paracrine actions of MSC in hydrogels were evaluated in co-cultures with human macrophages from healthy blood donors or with osteoblasts from bone explants of patients with osteonecrosis of the femoral head. Lower matrix stiffness resulted in higher MSC viability and migration. Cell migration rate from collagen hydrogels was higher than from fibrin matrices. The secretion of the immunomodulatory factors interleukin-6 (IL-6) and prostaglandin E. 2. (PGE. 2. ) by MSC in both collagen and fibrin hydrogels increased with increasing matrix stiffness. Tumor necrosis factor-α (TNF-α) secretion by macrophages cultured on collagen hydrogels was lower than on fibrin matrices. Interestingly, higher collagen matrix stiffness resulted in lower secreted TNF-α while the trend was opposite on fibrin hydrogels. In all cases, TNF-α levels were lower when macrophages were cultured on hydrogels containing MSC than on empty gels, an effect partially mediated by PGE. 2. Finally, mineralization capacity of osteoblasts co-cultured with MSC in hydrogels increased with increasing matrix stiffness, although this effect was more notably for collagen hydrogels. Paracrine interactions established by MSC in hydrogels with macrophages and osteoblasts are regulated by matrix composition and stiffness

Aims

Rheumatoid arthritis (RA) is a common chronic immune disease. Berberine, as its main active ingredient, was also contained in a variety of medicinal plants such as Berberaceae, Buttercup, and Rutaceae, which are widely used in digestive system diseases in traditional Chinese medicine with anti-inflammatory and antibacterial effects. The aims of this article were to explore the therapeutic effect and mechanism of berberine on rheumatoid arthritis.

Anterior cruciate ligament (ACL) injuries have been increasing, especially amongst adolescents. These injuries can increase the risk for early-onset knee osteoarthritis (OA). The consequences of late-stage knee OA include structural joint change, functional limitations and persistent pain. Interleukin-6 (IL-6) is a pro-inflammatory biomarker reflecting knee joint healing, and increasing evidence suggests that IL-6 may play a critical role in the development of pathological pain. The purpose of this study was to determine the relationship between subjective knee joint pain and function, and synovial fluid concentrations of the pro-inflammatory cytokine IL-6, in adolescents undergoing anterior cruciate ligament reconstruction surgery. Seven youth (12-17 yrs.) undergoing anterior cruciate ligament (ACL) reconstruction surgery participated in this study. They completed the Pedi International Knee Documentation Committee (Pedi-IKDC) questionnaire on knee joint pain and function. At the time of their ACL reconstruction surgery, synovial fluid samples were collected through aspiration to dryness with a syringe without saline flushing. IL-6 levels in synovial fluid (sf) were measured using enzyme linked immunosorbent assay. Spearman's rho correlation coefficient was used to determine the correlation between IL-6 levels and scores from the Pedi-IKDC questionnaire. There was a statistically significant correlation between sfIL-6 levels and the Pedi-IKDC Symptoms score (-.929, p=0.003). The correlations between sfIL-6 and Pedi-IKDC activity score (.546, p = .234) and between sfIL-6 and total Pedi-IKDC score (-.536, p = .215) were not statistically significant. This is the first study to evaluate IL-6 as a biomarker of knee joint healing in an adolescent population, reported a very strong correlation (-.929, p=0.003) between IL-6 in knee joint synovial fluid and a subjective questionnaire on knee joint pain. These findings provide preliminary scientific evidence regarding the relationship between knee joint pain, as determined by a validated questionnaire and the inflammatory and healing status of the patient's knee. This study provides a basis and justification for future longitudinal research on biomarkers of knee joint healing in patients throughout their recovery and rehabilitation process. Incorporating physiological and psychosocial variables to current return-to-activity (RTA) criteria has the potential to improve decision making for adolescents following ACL reconstruction to reduce premature RTA thereby reducing the risk of re-injury and risk of early-onset knee OA in adolescents

Aims

Acridine orange (AO) demonstrates several biological activities. When exposed to low doses of X-ray radiation, AO increases the production of reactive radicals (radiodynamic therapy (AO-RDT)). We elucidated the efficacy of AO-RDT in breast and prostate cancer cell lines, which are likely to develop bone metastases.

Aims

This study aimed, through bioinformatics analysis, to identify the potential diagnostic markers of osteoarthritis, and analyze the role of immune infiltration in synovial tissue.

Aims

Treatment outcomes for methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) using systemic vancomycin and antibacterial cement spacers during two-stage revision arthroplasty remain unsatisfactory. This study explored the efficacy and safety of intra-articular vancomycin injections for PJI control after debridement and cement spacer implantation in a rat model.

Aims

The aim of the HIPGEN consortium is to develop the first cell therapy product for hip fracture patients using PLacental-eXpanded (PLX-PAD) stromal cells.

Aims. The preoperative diagnosis of periprosthetic joint infection (PJI) remains a challenge due to a lack of biomarkers that are both sensitive and specific. We investigated the performance characteristics of polymerase chain reaction (PCR), interleukin-6 (IL6), and calprotectin of synovial fluid in the diagnosis of PJI. Methods. We performed systematic search of PubMed, Embase, The Cochrane Library, Web of Science, and Science Direct from the date of inception of each database through to 31 May 2021. Studies which described the diagnostic accuracy of synovial fluid PCR, IL6, and calprotectin using the Musculoskeletal Infection Society criteria as the reference standard were identified. Results. Overall, 31 studies were identified: 20 described PCR, six described IL6, and five calprotectin. The sensitivity and specificity were 0.78 (95% confidence interval (CI) 0.67 to 0.86) and 0.97 (95% CI 0.94 to 0.99), respectively, for synovial PCR;, 0.86 (95% CI 0.74 to 0.92), and 0.94 (95% CI 0.90 to 0.96), respectively, for synovial IL6; and 0.94 (95% CI 0.82 to 0.98) and 0.93 (95% CI 0.85 to 0.97), respectively, for synovial calprotectin. Likelihood ratio scattergram analyses recommended clinical utility of synovial fluid PCR and IL6 as a confirmatory test only. Synovial calprotectin had utility in the exclusion and confirmation of PJI. Conclusion. Synovial fluid PCR and IL6 had low sensitivity and high specificity in the diagnosis of PJI, and is recommended to be used as confirmatory test. In contrast, synovial fluid calprotectin had both high sensitivity and specificity with utility in both the exclusion and confirmation of PJI. We recommend use of synovial fluid calprotectin studies in the preoperative workup of PJI. Cite this article: Bone Joint J 2022;104-B(3):311–320

Aims

Prompt and sufficient broad-spectrum empirical antibiotic treatment is key to preventing infection following open tibial fractures. Succeeding co-administration, we dynamically assessed the time for which vancomycin and meropenem concentrations were above relevant epidemiological cut-off (ECOFF) minimal inhibitory concentrations (T > MIC) in tibial compartments for the bacteria most frequently encountered in open fractures. Low and high MIC targets were applied: 1 and 4 µg/ml for vancomycin, and 0.125 and 2 µg/ml for meropenem.

Aims

Circular RNA (circRNA) S-phase cyclin A-associated protein in the endoplasmic reticulum (ER) (circSCAPER, ID: hsa_circ_0104595) has been found to be highly expressed in osteoarthritis (OA) patients and has been associated with the severity of OA. Hence, the role and mechanisms underlying circSCAPER in OA were investigated in this study.

Aims

This study aimed to answer two questions: what are the best diagnostic methods for diagnosing bacterial arthritis of a native joint?; and what are the most commonly used definitions for bacterial arthritis of a native joint?

Aim. Diagnosis and isolation of a causative organism is imperative for successful treatment of periprosthetic joint infections (PJI). While there are several diagnostic algorithms using microbiology, serum and synovial markers, the preoperative diagnosis of a low-grade infection remains a challenge, particularly in patients with unsuccessful aspiration. An incisional biopsy may be used in these cases as additional diagnostic tool. In this retrospective study we evaluated microbiological findings, sensitivity, and specificity of open synovial biopsies in cases of inconclusive preoperative diagnostics. Methods. In a retrospective databank analysis (2010–2018), we identified 80 TKAs that underwent an open biopsy because of inconclusive results after applying the CDC Criteria (2010) or the MSIS (2011–2018) for PJI. Infection makers in the serum (C-reactive protein [CRP], leucocytes count and interleukin-6 [IL-6]) and in the synovial aspirate (leucocyte count, percentage of neutrophiles) prior to the biopsy were analyzed. All biopsies were performed by suprapatellar mini-arthrotomy. If a subsequent revision surgery was performed, the isolated organisms in the open biopsy were compared to the results in the revision surgery and sensitivity and specificity were calculated. Serum markers were checked for correlation with a positive result in the open biopsy using Cramer-V and Chi. 2. -Test. Results. A positive result in the open biopsy occurred in 32 cases (40%) while 48 cases (60%) showed no growth of microorganisms. A preoperative elevated serum CRP (≥1mg/dl) showed a significant correlation for a positive biopsy (p=0.04). The odds ratio for a positive biopsy was 2.57 (95% CI 1.02–6.46) with elevated serum CRP. A revision surgery of the TKA with additional tissue sampling was performed in 27 (84%) cases with a positive biopsy and in 32 (67%) cases with a negative biopsy. The intraoperative tissue samples from the revision surgery showed microbial growth in only 52% of cases that were believed to be culture positive from the biopsy results, while positive cultures occurred in 41% of the cases with an initially negative biopsy. Patients with ≥ two cultures of the same microorganism in the biopsy presented a positive result in 73% of their revision surgeries. The open biopsy showed a sensitivity of 48% with a specificity of 62% in our collective if revision surgery was performed. Conclusion. Open biopsy may be considered with inconclusive preoperative serum and synovial fluid diagnostics for PJI, but sensitivity and specificity were rather low in this special collective. Further studies with bigger collectives should be performed to determine potential markers with a higher sensitivity