Synovial Samples Research Articles

Bioinformatics analysis of hub genes as osteoarthritis prognostic biomarkers

Osteoarthritis (OA) is a progressive cartilage degradation disease, concomitant with synovitis, osteophyte formation, and subchondral bone sclerosis. Over 37% of the elderly population is affected by OA, and the number of cases is increasing as the global population ages. Therefore, the objective of this study was to identify and analyze the hub genes of OA combining with comprehensive bioinformatics analysis tools to provide theoretical basis in further OA effective therapies. Two sample sets of GSE46750 contained 12 pairs OA synovial membrane and normal samples harvested from patients as well as GSE98918 including 12 OA and non-OA patients were downloaded from the Gene Expression Omnibus database (GEO) database. Differentially expressed genes (DEGs) were identified using Gene Expression Omnibus 2R (GEO2R), followed by functional enrichment analysis, protein–protein interaction networks construction. The hub genes were identified and evaluated. An OA rat model was constructed, hematoxylin and eosin staining, safranin O/fast green staining, cytokines concentrations of serum were used to verify the model. The hub genes expression level in the knee OA samples were verified using RT-qPCR. The top 20 significantly up-regulated and down-regulated DEGs were screened out from the two datasets, respectively. The top 18 GO terms and 10 KEGG pathways were enriched. Eight hub genes were identified, namely MS4A6A, C1QB, C1QC, CD74, CSF1R, HLA-DPA1, HLA-DRA and ITGB2. Among them, the hub genes were all up-regulated in in vivo OA rat model, compared with healthy controls. The eight hub genes identified (MS4A6A, C1QB, C1QC, CD74, CSF1R, HLA-DPA1, HLA-DRA and ITGB2) were shown to be associated with OA. These genes can serve as disease markers to discriminate OA patients from healthy controls.

Two-dimensional liquid chromatography measurement of meropenem concentration in synovial fluid of patients with periprosthetic joint infection.

Periprosthetic joint infection (PJI) is a catastrophic complication following joint replacement surgery. One potential treatment approach for PJI could be the combination of one-stage revision and intra-articular infusion of antibiotics. Meropenem is one of the commonly used intra-articular antibiotics in our institution. Determining the concentration of meropenem in the joint cavity could be crucial for optimizing its local application, effectively eradicating biofilm infection, and improving PJI treatment outcomes. In this study, we developed a simple, precise, and accurate method of two-dimensional liquid chromatography (2D-LC) for determining the concentration of meropenem in human synovial fluid. The method was then validated based on the guidelines of the Food and Drug Administration and the Chinese Pharmacopoeia. Meropenem showed good linearity in the range of 0.31-25.01 μg/mL (r ≥ .999). Selectivity, intra-day and inter-day precision and accuracy, extraction recovery, and stability validation results were all within the acceptance range. This method has been successfully applied to the determination of synovial fluid samples from PJI patients, providing a useful detection method for meropenem therapeutic drug monitoring (TDM) in PJI patients.

Adalimumab Effectively Decreases Inflammation Downstream of TNFα Signaling in Synoviocytes from Extended Oligoarticular Juvenile Idiopathic Arthritis.

Fibroblast-like synoviocytes (FLS) play a critical role in inflammation that contributes to disease progression in juvenile idiopathic arthritis (JIA). In rheumatoid arthritis (RA), FLS express tumor necrosis factor alpha (TNFα). TNFα signaling has been shown to be upstream of transforming growth factor beta (TGFβ) signaling. Overexpression of TNFα and TGFβ, as well as related proteins, can cause increased inflammation in RA. In this study, we examine the effects of inhibiting TNFα signaling with adalimumab on FLS isolated from synovial fluid of patients with JIA. Synovial fluid samples were selected from 41 patients in our repository. Of these samples, 23 were diagnosed with persistent oligoarticular JIA and 18 were diagnosed with extended oligoarticular JIA. All samples were taken prior to patients extending to a polyarticular course, or what we termed extended-to-be (ETB), and were on no medications or nonsteroidal anti-inflammatory drugs (NSAIDs) only at the time of arthrocentesis. For cell studies, FLS were isolated from synovial fluid and treated with adalimumab for 24h. Protein antibody arrays were performed by RayBiotech, Inc. according to their protocols. In persistent FLS, TNFα (fold change [FC] = 1.2 p = 0.001), TGFβ (FC = 1.5 p = 0.001), lymphotoxin alpha (LTα) (FC = 4.3 p = 0.015), soluble tumor necrosis factor receptor1 (sTNFRI) (FC = 5.1 p = 0.008), and soluble tumor necrosis factor receptor2 (sTNFRII) (FC = 3.8 p = 0.025) were significantly elevated in adalimumab treated cells compared to untreated cells. In ETB FLS, TNFα was significantly elevated (FC = 1.04 p = 0.023) while TGFβ (FC = 1.03 p = 0.037) was significantly decreased in adalimumab-treated cells compared to untreated cells. This data suggests that, after only 24h, adalimumab is effective at decreasing inflammation that occurs downstream of initial TNFα signaling in extended-to-be fibroblast-like synoviocytes.

Trabecular, but not cortical, bone tissue protein synthesis rates are lower in the femoral head when compared to the proximal femur following an intracapsular hip fracture.

All musculoskeletal tissues are in a constant state of turnover, with a dynamic equilibrium between tissue protein synthesis and breakdown rates. The synthesis of protein allows musculoskeletal tissues to heal following injury. Yet, impaired tissue healing is observed following certain injuries, such as geriatric hip fractures. It is assumed that the regenerative properties of femoral head bone tissue are compromised following an intracapsular hip fracture and therefore hip replacement surgery is normally performed. However, the actual impact on in vivo bone protein synthesis rates has never been determined. In the present study, 10 patients (age: 79±10 y, BMI: 24±4kg/m2) with an acute (<24h) intracapsular hip fracture received a primed continuous intravenous infusion of L-[ring-13C6]-phenylalanine before and throughout their hip replacement surgery. Trabecular and cortical bone tissue from both the femoral head and proximal femur were sampled during surgery to assess protein synthesis rates of affected (femoral head) and unaffected (proximal femur) bone tissue, respectively. In addition, tissue samples of gluteus maximus muscle, synovium, ligamentum teres, and femoral head cartilage were collected. Tissue-specific protein synthesis rates were assessed by measuring L-[ring-13C6]-phenylalanine incorporation in tissue protein. Femoral head trabecular bone protein synthesis rates (0.056 [0.024-0.086] %/h) were lower when compared to proximal femur trabecular bone protein synthesis rates (0.081 [0.056-0.118] %/h; P=0.043). Cortical bone protein synthesis rates did not differ between the femoral head and proximal femur (0.041 [0.021-0.078] and 0.045 [0.028-0.073] %/h, respectively; P>0.05). Skeletal muscle, synovium, ligamentum teres, and femoral head cartilage protein synthesis rates averaged 0.080 [0.048-0.089], 0.093 [0.051-0.130], 0.121 [0.110-0.167], and 0.023 [0.015-0.039] %/h, respectively. In contrast to the general assumption that the femoral head is avital after an intracapsular displaced hip fracture in the elderly, our data show that bone protein synthesis is still ongoing in femoral head bone tissue during the early stages following an intracapsular hip fracture in older patients. Nonetheless, trabecular bone protein synthesis rates are lower in the femoral head when compared to the proximal femur in older patients following an acute intracapsular hip fracture. Trial register no: NL9036.

The Histopathological Landscape of Synovitis in Hemophilic Arthropathy

Recurrent joint bleeding leads to chronic arthropathy in severe hemophilia A and B. With the recent introduction of novel therapies and the increased availability of treatments for patients with hemophilia, a very tight control of bleeding is achievable, but some patients still experience synovitis oat target joints. A deeper knowledge of the synovial membranes in hemophilic synovitis may help the personalised treatment. However, very few data are available regarding the histopathological characteristics of the synovial membrane of patients with hemophilic arthropathy. We studied the histopathological aspects of the synovial membranes of nine patients undergoing orthopedic surgery in order to describe the overall characteristics and the immune infiltrate. Hematoxylin-eosin coloration was applied. Immunohistochemical analysis was performed and two synovitis scores currently used for rheumatoid arthritis were applied: the Krenn and the Humby scores. Moreover, we evaluated synovial collagen fibrosis by means of Masson trichromic staining, grading subintimal fibrosis semiquantitatively. Iron deposits were parallelly assessed with Perls histochemical stain and graded semiquantitatively. For each case we also evaluated whether iron deposits were mostly found in the intracellular (mainly siderophages) or extracellular compartment. Nine patients (six affected by severe hemophilia A, one by moderate hemophilia A and two by severe hemophilia B) with a mean age of 41 ± 14 years, were included. All patients were in prophylaxis with replacement drugs. Synovial membrane was collected during surgery (four total knee replacement, one arthroscopic knee synovectomy, two total ankle replacement, two arthroscopic ankle debridement), following good clinical practice. Informed consent was obtained before the procedure. All the synovial membrane samples were characterised by synovial hyperplasia and hemosiderin deposits. In seven out of nine samples a pauci-immune infiltrate was observed, whereas in two samples a lymphoid-myeloid infiltrate with lymphoid aggregates was present. All cases showed ≥1 grade fibrosis, with eight out of nine cases showing moderate to severe subintimal fibrosis and only one case with lympho-myeloid infiltrate exhibiting mild fibrosis. Iron deposition across the cohort was heterogeneous, with equal distribution of cases with mild (33%), moderate (33%) and severe (33%) iron deposition. Iron deposits were observed mostly in the intracellular compartment (i.e siderophages) with scattered extracellular presence, with the exception of one case with mild and almost exclusive extracellular deposition. In hemophilic arthropathy, we fount typical characteristics of the blood-induced synovial hyperplasia in the majority of the studied synovial membranes, with a pauci-immune infiltrate resembling degenerative arthropathies such as osteoarthritis. By contrast, lymphoid aggregates similar to inflammatory arthritis were less frequent. Fibrosis and iron deposition were more frequent than in osteoarthritis. It should be noted that all the samples were collected from patients undergoing orthopedic surgery due to long-lasting synovitis. A larger study including patients at different stages of arthropathy may help clarify if a different histopathological landscape may correlate with a different clinical history and predict the response to different therapeutic approaches.

Role and Therapeutic Potential for Targeting Fibroblast Growth Factor 10/FGFR1 in Relapsed Rheumatoid Arthritis.

Fibroblast-like synoviocytes (FLSs) contribute to inflammation and joint damage in rheumatoid arthritis (RA). However, the regulatory mechanisms of FLSs in relapse and remission of RA remain unknown. Identifying FLS heterogeneity and their underlying pathogenic roles may lead to discovering novel disease-modifying antirheumatic drugs. Combining single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics, we sequenced six matched synovial tissue samples from three patients with relapse RA and three patients in remission. We analyzed the differences in the transcriptomes of the FLS subsets between the relapse and remitted phases. We validated several key signaling pathways using quantitative real-time PCR(qPCR)and multiplex immunohistochemistry (mIHC). We further targeted the critical signals in vitro and in vivo using the collagen-induced arthritis (CIA) model in rats. Lining and sublining FLS subsets were identified using scRNA-seq. Differential analyses indicated that the fibroblast growth factor (FGF) pathway was highly activated in the lining FLSs from patients with relapse RA for which mIHC confirmed the increased expression of FGF10. Although the type I interferon pathway was also activated in the lining FLSs, in vitro stimulation experiment suggested that it was independent of the FGF10 pathway. FGF10 knockdown by small interfering RNA in FLSs significantly reduced the expression of receptor activator of NF-κB ligand. Moreover, recombinant FGF10 protein enhanced bone erosion in the primary human-derived pannus cell culture, whereas the FGF receptor (FGFR) 1 inhibitor attenuated this process. Finally, administering an FGFR1 inhibitor displayed a therapeutic effect in a CIA rat model. The FGF pathway is a critical signaling pathway in relapse RA. Targeted tissue-specific inhibition of FGF10/FGFR1 may provide new opportunities to treat patients with relapse RA.

Enhancement of Chondrogenic Markers by Exosomes Derived from Cultured Human Synovial Fluid-Derived Cells: A Comparative Analysis of 2D and 3D Conditions.

The goal of this pilot study was to investigate the effects of exosomes derived from synovial fluid-derived cells (SFDCs) cultured under normoxic conditions in a two-dimensional (2D) monolayer or encapsulated within a three-dimensional (3D) matrix for chondrogenic differentiation in vitro and cartilage defect repair in vivo. Synovial fluid samples were obtained from three patients, and SFDCs were isolated and expanded either in a 2D monolayer culture or seeded within a transglutaminase cross-linked gelatin (Col-Tgel) to create a 3D gel culture. Exosomes derived from each environment were isolated and characterized. Then, their effects on cartilage-cell proliferation and chondrogenic differentiation were assessed using an in vitro organoid model, and their potential for enhancing cartilage repair was evaluated using a rat cartilage defect model. SFDCs obtained from different donors reached a state of senescence after four passages in 2D culture. However, transferring these cells to a 3D culture environment mitigated the senescence and improved cell viability. The 3D-cultured exosomes exhibited enhanced potency in promoting chondrogenic differentiation, as evidenced by the increased expression of chondrogenic genes and greater deposition of cartilage-specific extracellular matrix. Furthermore, the 3D-cultured exosomes demonstrated superior effectiveness in enhancing cartilage repair and exhibited better healing properties compared to exosomes derived from a 2D culture. The optimized 3D culture provided a more favorable environment for the proliferation of human synovial cells and the secretion of exosomes compared to the 2D culture. The 3D-cultured exosomes exhibited greater potential for promoting chondrogenic gene expression in vitro and demonstrated improved healing properties in repairing cartilage defects compared to exosomes derived from the 2D culture.

The Role of Chlamydia pneumoniae in the Aetiology of Autoimmune Diseases.

Introduction The most prevalent chronic human autoimmune disorder worldwide is rheumatoid arthritis. Synovial samples from acute-phase patients are polymerase chain reaction-positive for Chlamydia pneumoniae (C. pneumoniae)DNA and express chlamydial hsp60. Furthermore, anti-cyclic citrullinated peptide (anti-CCP) antibodies promote apoptosis of mature human Saos-2 osteoblasts via cell surface binding to citrullinated heat shock protein 60 (HSP60). Hence, we hypothesised that C. pneumoniae infection is associated with anti-CCP antibodies. Methods C. pneumoniae IgA and anti-CCP antibody levels were determined in 26 healthy subjects in this cross-sectional study. Serum C. pneumoniae IgA antibody levels were assessed using an enzyme-linked immunosorbent assay. Serum anti-CCP antibody levels were assessed using fluoroenzymeimmunoassay. Results There was a highly significant positive correlation between the two sets of antibodies (rs = 0.621; P = 0.0007). Linear regression analysis showed that this correlation was not the result of age or sex. Discussion A biologically plausible mechanism is put forward for these results, involving HSP60 acting as an endogenous ligand for toll-like receptor 4 (TLR4) and the interaction of TLR4 with lipopolysaccharides, which occur in the outer membrane of the C. pneumoniae elementary body. Pronounced pro-inflammatory mediator secretion then takes place. The release of Ca2+ ions may then activate local peptidylarginine deiminases, leading to the formation of CCPs and thus the reported finding. Confirmation of these results may have potential clinical implications in terms of diagnosis, including pre-symptomatic diagnosis, and treatment.

Comparative analysis of late-stage rheumatoid arthritis and osteoarthritis reveals shared histopathological features

ObjectivesOsteoarthritis (OA) is a debilitating and heterogeneous condition, characterized by various levels of articular cartilage degradation, osteophytes formation and synovial inflammation. Multiple evidence suggest that synovitis may appear early in the disease development and correlates with disease severity and pain, therefore representing a relevant therapeutic target. In a typical synovitis-driven joint disease, namely rheumatoid arthritis (RA), several pathotypes have been described by our group and associated with clinical phenotypes, disease progression and response to therapy. However, whether these pathotypes can be also observed in the OA synovium is currently unknown. MethodsHere, using histological approaches combined with semi-quantitative scoring and quantitative digital image analyses, we comparatively characterize the immune cell infiltration in a large cohort of OA and RA synovial tissue samples collected at the time of total joint replacement. ResultsWe demonstrate that OA synovium can be categorized also into three pathotypes and characterized by disease- and stage-specific features. Moreover, we revealed that pathotypes specifically reflect distinct levels of peripheral inflammation. ConclusionsIn this study, we provide a novel and relevant pathological classification of OA synovial inflammation. Further studies investigating synovial molecular pathology in OA may contribute to the development of disease-modifying therapies.

Expression quantitative trait loci analysis in rheumatoid arthritis identifies tissue specific variants associated with severity and outcome

ObjectiveGenome-wide association studies have successfully identified more than 100 loci associated with susceptibility to rheumatoid arthritis (RA). However, our understanding of the functional effects of genetic variants in causing RA...

A fluorogenic micrococcal nuclease-based probe for fast detection and optical imaging of Staphylococcus aureus in prosthetic joint and fracture-related infections

PurposeStaphylococcus aureus is the most common and impactful multi-drug resistant pathogen implicated in (periprosthetic) joint infections (PJI) and fracture-related infections (FRI). Therefore, the present proof-of-principle study was aimed at the rapid detection of S. aureus in synovial fluids and biofilms on extracted osteosynthesis materials through bacteria-targeted fluorescence imaging with the ‘smart-activatable’ DNA-based AttoPolyT probe. This fluorogenic oligonucleotide probe yields large fluorescence increases upon cleavage by micrococcal nuclease, an enzyme secreted by S. aureus.MethodsSynovial fluids from patients with suspected PJI and extracted osteosynthesis materials from trauma patients with suspected FRI were inspected for S. aureus nuclease activity with the AttoPolyT probe. Biofilms on osteosynthesis materials were imaged with the AttoPolyT probe and a vancomycin-IRDye800CW conjugate (vanco-800CW) specific for Gram-positive bacteria.Results38 synovial fluid samples were collected and analyzed. Significantly higher fluorescence levels were measured for S. aureus-positive samples compared to, respectively, other Gram-positive bacterial pathogens (p < 0.0001), Gram-negative bacterial pathogens (p = 0.0038) and non-infected samples (p = 0.0030), allowing a diagnosis of S. aureus-associated PJI within 2 h. Importantly, S. aureus-associated biofilms on extracted osteosynthesis materials from patients with FRI were accurately imaged with the AttoPolyT probe, allowing their correct distinction from biofilms formed by other Gram-positive bacteria detected with vanco-800CW within 15 min.ConclusionThe present study highlights the potential clinical value of the AttoPolyT probe for fast and accurate detection of S. aureus infection in synovial fluids and biofilms on extracted osteosynthesis materials.

Performance evaluation of the automated body fluid analysis of the new Sysmex XR haematology analyser

Abstract Objectives The cellular composition of body fluids (BF) provides insight into disease pathology and is an important diagnostic parameter. The well-established Sysmex XN haematology analyser (XN) offers automated BF analysis and is in routine use in many laboratories. In this study the performance of the new Sysmex XR analyser (XR) in testing BF is compared to the XN. Methods Cerebrospinal, pleural, peritoneal, and synovial fluids, as well as bronchoalveolar lavage (BAL) samples, were processed in BF mode on both analysers. Standard statistical methods were used to evaluate the performance of XR compared to the reference XN. Results Cell counts were generated from a total of 356 measurements from 307 patient BF samples. After application of exclusion criteria, 86 cerebrospinal, 77 peritoneal, 78 pleural, and 89 synovial fluid sample pairs were compared. An excellent correlation coefficient (r) between the two analysers was observed for all diagnostic parameters; WBC-BF: 0.996, RBC-BF: 0.974, TC-BF: 0.995, MN#: 0.994, MN%: 0.830, PMN#: 0.985 and PMN%: 0.835. The research parameters also performed equally well (r values of 0.900–0.994). The performance of diluted and undiluted samples was equally good. Similar results for diagnostic and research parameters were obtained from 62 BAL samples (r values of 0.899–0.992). Conclusions This study demonstrates that the automated BF counts on the new Sysmex XR analyser are equivalent to that of the XN for all BF types analysed.

A Targeted Exosome Therapeutic Confers Both CfDNA Scavenging and Macrophage Polarization for Ameliorating Rheumatoid Arthritis.

Only a minority of rheumatoid arthritis (RA) patients achieve disease remission, so the exploration of additional pathogenic factors and the development of new therapeutics are needed. Here, strong correlations among the cell-free DNA (cfDNA) level and the inflammatory response in clinical synovial fluid samples and RA disease activity are discovered. The important role of cfDNA in disease development in a collagen-induced arthritis (CIA) murine model is also demonstrated. Building on these findings, a novel therapeutic based on anti-inflammatory (M2) macrophage-derived exosomes as chassis, that are modified with both oligolysine and matrix metalloproteinase (MMP)-cleavable polyethylene glycol (PEG) on the membrane, is developed. After intravenous injection, PEG-enabled prolonged circulation and C─C motif chemokine ligand-directed accumulation together result in enrichment at inflamed joints. Following subsequent MMP cleavage, the positively charged oligolysine is exposed for cfDNA scavenging, while exosomes induce M2 polarization. By using a classical CIA murine model and a newly established CIA canine model, it is demonstrated that the rationally designed exosome therapeutic substantially suppresses inflammation in joints and provides strong chondroprotection and osteoprotection, revealing its potential for effective CIA amelioration.

A rare first case of prosthetic knee joint infection by Citrobacter koseri

Citrobacter generally colonizes the gastrointestinal and urogenital tracts of humans, but musculoskeletal infection by Citrobacter in the elderly is extremely rare. To our knowledge, less than 15 cases of causing musculoskeletal infection have been reported in the literature. In the last few years, there has been a considerable increase in the incidence of prosthetic knee joint infection in the United States, with a higher risk of infection in the first two years following surgery. Although gram-positive bacteria like Staphylococcus and Streptococci are more common cause of PJI, gram-negative bacteria can also be found in infected joints. We report the first case of PJI in the left knee due to in an 82-year-old adult two years after bilateral knee arthroplasty. This case report intends to educate and raise awareness for causing PJI as a long term post-op complication even in healthy individuals. We searched articles on Pubmed and Medline for PJI and citrobacter infection. We report clinically and microbiologically confirmed in a synovial fluid sample of the left knee joint. should be considered as a possible pathogen for PJI in long term setting even in an otherwise healthy individual.

Intra-articular bone marrow mononuclear cell therapy improves lameness from naturally occurring equine osteoarthritis.

Osteoarthritis (OA) can be debilitating and is related to impaired resolution of synovial inflammation. Current treatments offer temporary relief of clinical signs, but have potentially deleterious side effects. Bone marrow mononuclear cells (BMNC) are a rich source of macrophage progenitors that have the ability to reduce OA symptoms in people and inflammation in experimentally-induced synovitis in horses. The objective of this study was to evaluate the ability of intra-articular BMNC therapy to improve clinical signs of naturally occurring equine OA. Horses presenting with clinical and radiographic evidence of moderate OA in a single joint were randomly assigned to 1 of 3 treatment groups: saline (negative control), triamcinolone (positive control), or BMNC (treatment group). Lameness was evaluated subjectively and objectively, joint circumference measured, and synovial fluid collected for cytology and growth factor/cytokine quantification at 0, 7, and 21 days post-injection. Data were analyzed using General Estimating Equations with significance set at p < 0.05. There were no adverse effects noted in any treatment group. There was a significant increase in synovial fluid total nucleated cell count in the BMNC-treated group on day 7 (median 440; range 20-1920 cells/uL) compared to day 0. Mononuclear cells were the predominant cell type across treatments at all time points. Joint circumference decreased significantly in the BMNC-treated group from days 7 to 21 and was significantly lower at day 21 in the BMNC-treated group compared to the saline-treated group. Median objective lameness improved significantly in the BMNC group between days 7 and 21. GM-CSF, IL-1ra, IGF-1, and TNF-α were below detectable limits and IL-6, IL-1β, FGF-2 were detectable in a limited number of synovial fluid samples. Inconsistent and limited differences were detected over time and between treatment groups for synovial fluid PGE2, SDF-1, MCP-1 and IL-10. Decreased lameness and joint circumference, coupled with a lack of adverse effects following BMNC treatment, support a larger clinical trial using BMNC therapy to treat OA in horses.

Effect of smoking on the redox status of knee osteoarthritis: A preliminary study.

Even though smoking has been scarcely studied in osteoarthritis (OA) etiology, it is considered a controversial risk factor for the disease. Exposure to tobacco smoke has been reported to promote oxidative stress (OS) as part of the damage mechanism. The aim of this study was to assess whether smoking increases cartilage damage through the generation of OS. Peripheral blood (PB) and synovial fluid (SF) samples from patients with OA were analyzed. The samples were stratified according to smoking habit, Kellgren-Lawrence score, pain, and cotinine concentrations in PB. Malondialdehyde (MDA), methylglyoxal (MGO), advanced protein oxidation products (APOPs), and myeloperoxidase (MPO) were assessed; the activity of antioxidant enzymes such as gamma-glutamyl transferase (GGT), glutathione S-transferase (GST) and catalase (CAT), as well as the activity of arginase, which favors the destruction of cartilage, was determined. When stratified by age, for individuals <60 years, the levels of MDA and APOPs and the activity of MPO and GST were higher, as well as antioxidant system activity in the smoking group (OA-S). A greater degree of pain in the OA-S group increased the concentrations of APOPs and arginase activity (P < 0.01 and P < 0.05, respectively). Arginase activity increased significantly with a higher degree of pain (P < 0.01). Active smoking can be an important risk factor for the development of OA by inducing systemic OS in young adults, in addition to reducing antioxidant enzymes in older adults and enhancing the degree of pain and loss of cartilage.

Clinicopathological Evaluation of Naturally Occurring Septic Arthritis in the Bovine Calves

Background: Septic arthritis affects ruminant welfare because, if left untreated, it can cause chronic pain and limit the mobility of affected joints. Objectives: This study aimed to investigate the clinical and pathological changes in arthritic bovine calves. Methods: The study was conducted on 12 calves with swollen knees or carpal joints. All calves were evaluated through clinical, radiographic, and ultrasonographic examination. Peripheral blood was aspirated from each to assess hematobiochemical changes. Synovial fluid and infected swab samples were subjected to bacteriological analysis, and a synovial biopsy was taken for histological examination. Results: Ultrasound revealed inflammatory effusions with various echogenicity in the afflicted joint capsule, while radiography showed remarkable swelling of joints and surrounding structures and the development of new bone. Regarding hematological variables, the value of total erythrocyte count, total leukocyte count, and erythrocyte sedimentation rate significantly (P&lt;0.05) increased in septic arthritic calves compared to healthy calves. In the arthritis group, the serum concentration of alanine transaminase, alkaline phosphatase, and aspartate aminotransferase was considerably (P&lt;0.05) higher than in healthy calves. The total protein and urea values were significantly (P&lt;0.05) decreased in calves with infected arthritis. From the synovial fluid and purulent discharge of the joints, Staphylococcus aureus and Escherichia coli were isolated. Histopathology of synovial tissue revealed chronic suppurative inflammation with intense hyperplasia of joint synovium. Conclusion: The results of this study may aid veterinarians in effectively diagnosing and treating septic arthritis in calves.

Proopiomelanocortin and its potential functions in the pathological synovium of patients with osteoarthritis.

Osteoarthritis (OA) is a chronic degenerative disease of the joints, adversely affecting the quality of life for the patients. To better understand the mechanisms underlying the pathological changes in osteoarthritis and identify the key genes associated with osteoarthritis pathogenesis, we utilized a comprehensive bioinformatics approach to analyze the transcriptome between osteoarthritis synovial and control samples with public microarray datasets. First, the GSE82107 microarray dataset containing ten osteoarthritis synovial and seven control samples were selected from the Gene Expression Omnibus (GEO) database. A total of 52 overlapped differentially expressed genes (DEGs) in GSE82107 and OA-associated genes in the Comparative Toxicogenomics Database were identified. These OA-associated DEGs were further incorporated into a protein-protein interaction (PPI) network. Gene proopiomelanocortin (POMC) was identified in the largest cluster of PPI network with Cytoscape. GO and KEGG analyses suggested that these genes were associated with multiple functions. Other GEO datasets of osteoarthritis synovial tissues, including GSE55235 and GSE55457, were used to validate the expression level of POMC. Quantitative polymerase chain reaction and western blot analyses were also used to test the expression levels of POMC in our osteoarthritis samples. We found POMC was positively associated with transporter complex, ion channel activity, and G protein-coupled receptor signaling pathway. This study highlighted the OA-associated gene POMC, and its related biological pathways, suggesting it served as a potential treatment target in osteoarthritis.

Gene signature based on glycolysis is closely related to immune infiltration of patients with osteoarthritis

BackgroundOsteoarthritis (OA) is a degenerative arthritis with high levels of clinical heterogeneity. Aberrant metabolism such as shifting from oxidative phosphorylation to glycolysis is a response to changes in the inflammatory microenvironment of OA. Therefore, there is a pressing need to identify novel glycolysis regulators during OA progression. MethodsWe systematically studied glycolysis patterns mediated by 141 glycolysis regulators in 74 human synovial samples and discussed the characteristics of the immune microenvironment modified by glycolysis. The random forest (RF) method was applied to screen candidate hub glycolysis regulators in OA. RT-qPCR was performed to validate these key regulators. Then distinct glycolysis patterns were identified, and systematic correlation between these glycolysis patterns and immune cell infiltration was analyzed. The glycolysis score was constructed to quantify glycolysis patterns together with immune infiltration of individual OA patient. Results56 glycolysis-related differentially expressed genes (DEGs) were identified between OA and non-OA samples. STC1, VEGFA, KDELR3, DDIT4 and PGAM1 were selected as candidate genes to predict the probability of OA. Two glycolysis patterns in OA were identified. Glycolysis cluster A with higher glycolysis score was related to an inflamed phenotype. ConclusionsTaken together, our results established a glycolysis-based genetic signature for OA, guided in-depth studies on the metabolic mechanism of OA, and facilitated to explore new clinical treatment strategies.

Synovium is a sensitive tissue for mapping the negative effects of systemic iron overload in osteoarthritis: identification and validation of two potential targets

BackgroundThe prevention and treatment of osteoarthritis (OA) pose a major challenge in its research. The synovium is a critical tissue in the systematic treatment of OA. The present study aimed to investigate potential target genes and their correlation with iron overload in OA patients.MethodsThe internal datasets for analysis included the microarray datasets GSE46750, GSE55457, and GSE56409, while the external datasets for validation included GSE12021 and GSE55235. The GSE176308 dataset was used to generate single-cell RNA sequencing profiles. To investigate the expression of the target genes in synovial samples, quantitative reverse transcription-PCR, western blotting, and immunohistochemical assay were conducted. ELISA was used to detect the levels of ferritin and Fe2+ in both serum and synovium.ResultsJUN and ZFP36 were screened from the differentially expressed genes, and their mRNA were significantly reduced in the OA synovium compared to that in normal synovium. Subsequently, complex and dynamically evolving cellular components were observed in the OA synovium. The mRNA level of JUN and ZFP36 differed across various cell clusters of OA synovium and correlated with immune cell infiltration. Moreover, ferritin and Fe2+ were significantly increased in the serum and synovium of OA patients. Further, we found that JUN elevated and ZFP36 decreased at protein level.ConclusionsThe synovium is a sensitive tissue for mapping the adverse effects of systemic iron overload in OA. JUN and ZFP36 represent potential target genes for attenuating iron overload during OA treatment. Some discrepancies between the transcription and protein levels of JUN suggest that post-transcriptional modifications may be implicated. Future studies should also focus on the roles of JUN and ZFP36 in inducing changes in cellular components in the synovium during OA pathogenesis.