Synovial Samples Research Articles

Determining the accuracy of the leukocyte esterase reagent strip test in the rapid diagnosis of adult septic arthritis

BackgroundsSeptic arthritis is a dangerous disease that occurs when microorganisms enter synovial fluid. It needs fast and accurate management; otherwise, it can harm the patient’s life. Currently, the tests measure WBC and PMN in SF, so we hypothesized to use a proxy that is easier and faster to measure. Leukocyte esterase is an enzyme secreted by neutrophils that can be found in the synovial fluid of SA patients. In this study, we tried to investigate the sensitivity and specificity of leukocyte esterase in diagnosing septic arthritis.MethodsWe obtained synovial fluid samples from forty-six patients suspected of having septic arthritis and fifty-eight healthy individuals and measured the WBCs, ESR, CRP, PMN, glucose, and protein of SF in 2021. We also used the leukocyte esterase dipstick test to investigate the level of LE in synovial fluid for one minute.ResultsBased on clinical and paraclinical criteria, sixteen out of the forty-six patients were diagnosed with SA. When (++) was considered positive, the sensitivity and specificity of the LE dipstick test for the diagnosis of SA were 93.7% (95% CI: 81.8–100%) and 60% (95% CI: 42.4–77.5%, P = 0.000), respectively. When both (+) and (++) were considered positive, they were 100% and 43.3% (95% CI: 25.6–61.0% P = 0.000), respectively. All the patients in the control group had negative cultures and LE test readings (specificity = 100%).ConclusionThe LE dipstick test can be a valuable diagnostic tool in the initial diagnosis of SA since it is affordable, fast, and reliable.

Identification and experimental validation of key genes in osteoarthritis based on machine learning algorithms and single-cell sequencing analysis

PurposeOsteoarthritis (OA) is a prevalent cause of disability in older adults. Identifying diagnostic markers for OA is essential for elucidating its mechanisms and facilitating early diagnosis. MethodsWe analyzed 53 synovial tissue samples (n = 30 for OA, n = 23 for the control group) from two datasets in the Gene Express Omnibus (GEO) database. We identified differentially expressed genes (DEGs) between the groups and applied dimensionality reduction using six machine learning algorithms to pinpoint characteristic genes (key genes). We classified the OA samples into subtypes based on these key genes and explored the differences in biological functions and immune characteristics among subtypes, as well as the roles of the key genes. Additionally, we constructed a protein-protein interaction network to predict small molecules that target these genes. Further, we accessed synovial tissue sample data from the single-cell RNA dataset GSE152805, categorized the cells into various types, and examined variations in gene expression and their correlation with OA progression. Validation of key gene expression was conducted in cellular experiments using the qPCR method. ResultsFour genes AGMAT, MAP3K8, PER1, and XIST, were identified as characteristic genes of OA. All can independently predict the occurrence of OA. With these genes, the OA samples can be clustered into two subtypes, which showed significant differences in functional pathways and immune infiltration. Eight cell types were obtained by analyzing the single-cell RNA data, with synovial intimal fibroblasts (SIF) accounting for the highest proportion in each sample. The key genes were found over-expressed in SIF and significantly correlated with OA progression and the content of immune cells (ICs). We validated the relative levels of key genes in OA and normal cartilage tissue cells, which showed an expression trend consistency with the bioinformatics result except for XIST. ConclusionFour genes, AGMAT, MAP3K8, PER1, and XIST are closely related to the progression of OA, and play as diagnostic and predictive markers in early OA.

Fcγ-receptor-IIIA bioactivity of circulating and synovial immune complexes in rheumatoid arthritis

ObjectivePrevious technical limitations prevented the proof of Fcγ-receptor (FcγR)-activation by soluble immune complexes (sICs) in patients. FcγRIIIa (CD16) is a risk factor in rheumatoid arthritis (RA). We aimed at determining...

Substantive Similarities Between Synovial Fluid and Synovial Tissue T cells in Inflammatory Arthritis Via Single-Cell RNA and T Cell Receptor Sequencing.

Synovial fluid (SF)-derived T cells are frequently studied as a proxy for investigating the synovial tissue (ST) T cell infiltrate in inflammatory arthritis. However, because ST is the primary site of inflammatory activity, there is debate as to whether SF provides a true reflection of the ST T cell population. In this study, we used single-cell RNA sequencing paired with single-cell T cell receptor (TCR) sequencing to directly compare memory T cells from paired samples of SF and ST from six patients with inflammatory arthritis to investigate their similarity in terms of TCR repertoire and T cell subset composition. The TCR repertoires of SF and ST T cells were strikingly similar, particularly for CD8+ T cells. A median of 49% of the total CD8+ TCR repertoire in SF was shared with ST, compared with 20% shared with blood. Similarly, 47% of the ST CD8+ TCR repertoire was shared with SF compared to 25% with blood. Furthermore, once the effect of collagenase digestion on gene expression by ST T cells had been accounted for, the frequencies of specific CD8+ and CD4+ T cell subsets were, in general, similar in SF and ST and were distinct from blood. Our results suggest that T cells migrate and equilibrate between the SF and ST and maintain similar phenotypes in both sites. We conclude that SF is an appropriate proxy for investigating the T cell infiltrate in inflamed synovium, particularly in terms of investigating the TCR repertoire.

Metagenomic next-generation sequencing promotes pathogen detection over culture in joint infections with previous antibiotic exposure.

To investigate the diagnostic value of metagenomic next-generation sequencing (mNGS) in detecting pathogens from joint infection (JI) synovial fluid (SF) samples with previous antibiotic exposure. From January 2019 to January 2022, 59 cases with suspected JI were enrolled. All cases had antibiotic exposure within 2 weeks before sample collection. mNGS and conventional culture were performed on SF samples. JI was diagnosed based on history and clinical symptoms in conjunction with MSIS criteria. The diagnostic values, including sensitivity, specificity, positive/negative predictive values (PPV/NPV), and accuracy, were in comparison with mNGS and culture. There were 47 of the 59 cases diagnosed with JI, while the remaining 12 were diagnosed with non-infectious diseases. The sensitivity of mNGS was 68.1%, which was significantly higher than that of culture (25.5%, p<0.01). The accuracy of mNGS was significantly higher at 71.2% compared to the culture at 39.0% (p <0.01). Eleven pathogenic strains were detected by mNGS but not by microbiological culture, which included Staphylococcus lugdunensis, Staphylococcus cohnii, Finegoldia magna, Enterococcus faecalis, Staphylococcus saprophytics, Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Acinetobacter pittii, Brucella ovis, andCoxiella burnetii. Antibiotic therapy was adjusted based on the mNGS results in 32 (68.1%) patients, including 12 (25.5%) and 20 (42.6%) patients, in whom treatment was upgraded and changed, respectively. All JI patients underwent surgery and received subsequent antibiotic therapy. They were followed up for an average of 23 months (20-27 months), and the success rate of treatment was 89.4%. Out of the 33 patients who had positive results for pathogens, reoperation was performed in 1 case (3.03%), while out of the 14 cases with negative results for both mNGS and cultures, reoperation was performed in 4 cases (28.6%). mNGS has advantages over conventional culture in detecting pathogens in SF samples from JI patients previously treated with antibiotics, potentially improving clinical outcomes.

The impact of ex vivo ozone injection into the synovial fluid in patients with knee osteoarthritis: A controlled clinical trial.

This study aimed to examine the effect of varying ozone doses on proinflammatory cytokine levels in the synovial fluid collected from individuals with knee osteoarthritis. The controlled clinical trial was conducted with 82 patients (61 females, 21 males; mean age: 63.1±10.0 years; range, 40 to 73 years) between 21 April 2023 and 20 May 2023. Synovial fluid samples were collected from the patients under ultrasound guidance and divided into three tubes, one of which was not injected with ozone, and the other two were injected with 10 and 30 gamma (γ) ozone, respectively. The total antioxidant status, total oxidant status, oxidative stress index, interleukin (IL)-1 beta (β), IL-6, and tumor necrosis factor-alpha (TNF-α) in the joint fluids were measured. The oxidative stress index and IL-1 β, IL-6, and TNF-α levels in the synovial fluid were lower at 10 and 30 γ compared to 0 and 10 γ, respectively. In vitro ozone injection at 30 gamma was more effective in reducing proinflammatory cytokines in the synovial fluid than that at 10 and 0 γ. Ozone injection into the pathological joint fluid was more effective in terms of total antioxidant status at 10 and 30 γ compared to 0 and 10 γ, respectively. No significant difference in total oxidant status was observed between the groups. This study showed that in vitro ozone injection at 30 γ was more effective in reducing proinflammatory cytokines in the synovial fluid and in improving total antioxidant status than that at 10 and 0 γ. The results showed the potential significance of the ozone injection dosage in treating knee osteoarthritis.

Application of microdialysis combined with lipidomics to analyze fatty acid metabolic changes in the disease process of rheumatoid arthritis

Rheumatoid arthritis (RA) is a metabolically active disease, with shifts in fatty acid metabolism during disease progression profoundly affecting the systemic inflammatory response. Altered fatty acid biomarker metabolism may be a key target for the treatment of RA. To investigate the changes of fatty acid metabolism in RA, collagen-induced arthritis (CIA) model was established. Microdialysis sampling was utilized to overcome the characteristic of occlusive joint cavity in vivo synovial fluid (SF) sampling. Lipidomic methods were established with the UHPLC-Orbitrap Exploris120 platform, and lipid measurements were performed on serum and SF samples. Then, multivariate statistical analyses were performed to detect changes in lipid metabolites induced by CIA. Consequently, a total of 22 potential biomarkers associated with differential fatty acids were screened and identified in serum, and 13 were identified in SF. Notably, alterations were observed in metabolites such as Hexadecanoic acid, Octadecanoic acid, Arachidonic acid, (+/-)11,12-EpETrE, DHA, DPA, Myristic acid, Suberic acid, and others. This study explored a new mechanism of the RA disease process from the perspective of fatty acid metabolism. It provided a new strategy for experimental research on determining the optimal time for establishing CIA model and screening clinical diagnostic biomarkers.

Lipidomic Signature of Plasma and Synovial Fluid in Patients with Osteoarthritis: Putative Biomarkers Determined by UHPLC-QTOF-ESI+MS.

Osteoarthritis (OA) is a prevalent joint condition causing pain and disability, especially in the elderly. Currently, OA diagnosis relies on clinical data and imaging, but recent interest in metabolomics suggests that early biochemical changes in biofluids, particularly synovial fluid (SF), could enable an earlier diagnosis and understanding of the disease. In this regard, we conducted a lipidomics study in 33 plasma and SF samples from OA patients and 20 OA-free controls to assess the diagnostic value of various lipid metabolites, using UHPLC-QTOF-ESI+MS. In plasma samples, 25 metabolites had area-under-the-curve (AUC) values higher than 0.9, suggesting a very good diagnostic potential for phosphatidic acid PA (16:0/16:0), PA (34:0), phosphatidylethanolamine PE (34:2), glucosylceramide, phosphatidylcholine PC (32:1), and other metabolites while in SF 20, metabolites had AUC values higher than 0.8, the vast majority belonging to lipid metabolism as well. Although the results align with the previous literature, larger cohort studies are necessary to confirm the diagnostic value of the lipid metabolites.

Mechanisms of treatment effects using allogeneic, umbilical cord-derived mesenchymal stromal stem cells (MSCs) in knee osteoarthritis: a pharmacological clinical study protocol

BackgroundKnee osteoarthritis (KOA) presents a prevalent orthopedic condition causing substantial impairment in the quality of life and imposing a significant societal and economic burden. Mesenchymal stromal/stem cells (MSCs), known for their regenerative properties and immunomodulatory effects, have emerged as a promising therapeutic avenue in regenerative medicine. Despite MSCs' therapeutic potential, their precise mechanisms of action in KOA remain underexplored.MethodsConducted as a randomized, open-label clinical trial, 20 patients will be enrolled, with 10 in the intervention group and 10 in the control group. The primary focus will be to explore the molecular mechanisms associated with MSC therapy. Biomarkers and gene expressions related to cartilage metabolism, inflammation, immune modulation, and pain in the synovial fluid, blood, and tissue samples will be analyzed. Patients will undergo pre- and post-treatment evaluations using patient-reported outcome measures (PROMs) and comprehensive clinical assessments.DiscussionThis is an exploratory study with the goal to provide comprehensive insights into the therapeutic effects of MSCs on a molecular level, potentially paving the way for optimized and more effective MSC-based therapies in the management of KOA, as well as furthering the development of novel treatment strategies.Trial registrationClinicalTrials.gov, NCT06078059. Registered on 5 October 2023.

Validation of a rapid collagenase activity detection technique based on fluorescent quenched gelatin with synovial fluid samples

BackgroundMeasuring collagenase activity is crucial in the field of joint health and disease management. Collagenases, enzymes responsible for collagen degradation, play a vital role in maintaining the balance between collagen synthesis and breakdown in joints. Dysregulation of collagenase activity leads to joint tissue degradation and diseases such as rheumatoid arthritis and osteoarthritis. The development of methods to measure collagenase activity is essential for diagnosis, disease severity assessment, treatment monitoring, and identification of therapeutic targets.ResultsThis study aimed to validate a rapid collagenase activity detection technique using synovial fluid samples. Antibody microarray analysis was initially performed to quantify the levels of matrix metalloproteinase-9 (MMP-9), a major collagenase in joints. Subsequently, the developed gelatin-based test utilizing fluorescence measurement was used to determine collagenase activity. There was a significant correlation between the presence of MMP-9 and collagenase activity. In addition, Lower Limit of Detection and Upper Limit of Detection can be preliminary estimated as 8 ng/mL and 48 ng/mL respectively.ConclusionsThe developed technique offers a potential point-of-care assessment of collagenase activity, providing real-time information for clinicians and researchers. By accurately quantifying collagenase activity, healthcare professionals can optimize patient care, improve treatment outcomes, and contribute to the understanding and management of joint-related disorders. Further research and validation are necessary to establish the full potential of this rapid collagenase activity detection method in clinical practice.

A significant difference of synovial mast cells in synovium from rotator cuff arthropathy compared to rotator cuff tears: A histological pilot study

ObjectiveAim of the present study was to compare the presence of Mast Cells (MCs) in synovial samples from gleno-humeral osteoarthritis (OA) and from control group. MethodsSynovial tissue samples were obtained during arthroplasty from 23 patients with gleno-humeral OA due to rotator cuff arthropathy (RCA) and from 20 patients without OA, constituting OA group and control group respectively. Before surgery self-reported pain was assessed using VAS score and OSS was used to value functional ability. Shoulder radiograph (Antero-posterior, Y-view and Grashey views) was evaluated by musculoskeletal radiologist and graded according to modified Samilson-Prieto classification.Synovial tissue, obtained during arthroplasty and arthroscopic procedure, was prepared to immunohistochemical analysis with anti-CD31 and anti-CD117 antibodies, to detect respectively endothelial cells and MCs at 40x magnification. Synovitis scores have been assessed. Under the control of the image processing system the distribution and the total number of vessels and MCs were determined. ResultsThe numbers of MCs and the area fraction (20x magnification) occupied by them were significantly higher in OA samples than in control tissue. The synovitis score was higher in OA patients with a positive correlation. Vessels number and area fraction were higher in OA patients than in controls. Analysis of MC number in relation to clinical data indicated positive correlation with the VAS score. ConclusionsThe distribution of MCs on synovium significantly differ between OA and control groups. Despite the design of the study could not conclude the cause-effect relationship, the presence of MCs might have role in OA pathogenesis. Level of evidenceHistological study.

Interleukin receptor therapeutics attenuate inflammation in canine synovium following cruciate ligament injury

ObjectiveIn the knee, synovial fibrosis after ligamentous injury is linked to progressive joint pain and stiffness. The objective of this study was to evaluate changes in synovial architecture, mechanical properties, and transcriptional profiles following naturally occurring cruciate ligament injury in canines and to test potential therapeutics that target drivers of synovial inflammation and fibrosis. DesignSynovia from canines with spontaneous cruciate ligament tears and from healthy knees were assessed via histology (n=10/group) and micromechanical testing (n=5/group) to identify changes in tissue architecture and stiffness. Additional samples (n=5/group) were subjected to RNA-sequencing to define the transcriptional response to injury. Finally, synovial tissue samples from injured animals (n=6 (IL1) or n=8 (IL6)/group) were assessed in vitro for response to therapeutic molecules directed against interleukin (IL) signaling (IL1 or IL6). ResultsCruciate injury resulted in increased synovial fibrosis, vascularity, inflammatory cell infiltration, and intimal hyperplasia. Additionally, the stiffness of both the intima and subintima regions were higher in diseased compared to healthy tissue. Differential gene expression analysis showed that diseased synovium had an upregulation of immune response and cell adhesion pathways and a downregulation of Rho protein transduction pathways. In vitro application of small molecule therapeutics targeting IL1 (anakinra) or IL6 (tocilizumab) dampened expression of inflammatory and matrix deposition mediators. ConclusionSpontaneous cruciate ligament injury in canines is associated with synovial inflammation and fibrosis in a relevant model for testing emerging intra-articular treatments. Small molecule therapeutics targeting IL pathways may be ideal interventions for delivery to the joint space after injury.

The role of BioFire Joint Infection Panel in diagnosing periprosthetic hip and knee joint infections in patients with unclear conventional microbiological results.

This study aimed to evaluate the BioFire Joint Infection (JI) Panel in cases of hip and knee periprosthetic joint infection (PJI) where conventional microbiology is unclear, and to assess its role as a complementary intraoperative diagnostic tool. Five groups representing common microbiological scenarios in hip and knee revision arthroplasty were selected from our arthroplasty registry, prospectively maintained PJI databases, and biobank: 1) unexpected-negative cultures (UNCs), 2) unexpected-positive cultures (UPCs), 3) single-positive intraoperative cultures (SPCs), and 4) clearly septic and 5) aseptic cases. In total, 268 archived synovial fluid samples from 195 patients who underwent acute/chronic revision total hip or knee arthroplasty were included. Cases were classified according to the International Consensus Meeting 2018 criteria. JI panel evaluation of synovial fluid was performed, and the results were compared with cultures. The JI panel detected microorganisms in 7/48 (14.5%) and 15/67 (22.4%) cases related to UNCs and SPCs, respectively, but not in cases of UPCs. The correlation between JI panel detection and infection classification criteria for early/late acute and chronic PJI was 46.6%, 73%, and 40%, respectively. Overall, the JI panel identified 12.6% additional microorganisms and three new species. The JI panel pathogen identification showed a sensitivity and specificity of 41.4% (95% confidence interval (CI) 33.7 to 49.5) and 91.1% (95% CI 84.7 to 94.9), respectively. In total, 19/195 (9.7%) could have been managed differently and more accurately upon JI panel evaluation. Despite its microbial limitation, JI panel demonstrated clinical usefulness by complementing the traditional methods based on multiple cultures, particularly in PJI with unclear microbiological results.

Synovial Fluid Cutibacterium acnes Antigen Is Detected Among Shoulder Samples with High Inflammation and Early Culture Growth.

An emerging paradigm suggests that positive Cutibacterium acnes shoulder cultures can result from either true infection or contamination, with true infections demonstrating a host inflammatory response and early culture growth. This clinical retrospective study examines the relationship between C. acnes antigen, C. acnes culture results, and inflammation. From January 2021 to July 2023, 1,365 periprosthetic synovial fluid samples from 347 institutions were tested for shoulder infection at a centralized clinical laboratory. A biomarker scoring system based on the 2018 International Consensus Meeting (ICM) definition was utilized to assign each sample an inflammation score. Associations between inflammation, culture results, and C. acnes antigen results were assessed utilizing cluster and correlation analyses. Of 1,365 samples, 1,150 were culture-negative and 215 were culture-positive (94 C. acnes and 121 other organisms). Among the 94 C. acnes culture-positive samples, unsupervised clustering revealed 2 distinct sample clusters (silhouette coefficient, 0.83): a high-inflammation cluster (n = 67) and a low-inflammation cluster (n = 27). C. acnes antigen levels demonstrated moderate-strong positive correlation with inflammation (Spearman ρ, 0.60), with 166-fold higher levels of C. acnes antigen in high-inflammation samples (16.6 signal/cutoff [S/CO]) compared with low-inflammation samples (0.1 S/CO) (p < 0.0001). The days to C. acnes culture positivity demonstrated weak-inverse correlation with inflammation (Spearman ρ = -0.38), with 1.5-fold earlier growth among the 67 high-inflammation samples (6.7 compared with 10.4 days; p < 0.0001). Elevated C. acnes antigen was observed in only 4 (0.38%) of 1,050 low-inflammation culture-negative samples and in only 5 (4.9%) of 103 high-inflammation non-C. acnes-positive cultures. However, 19.0% of high-inflammation, culture-negative samples demonstrated elevated C. acnes antigen. Synovial fluid C. acnes antigen was detected among shoulder samples with high inflammation and early culture growth, supporting the emerging paradigm that these samples represent true infection. Future research should explore antigen testing to differentiate contamination from infection and to identify culture-negative C. acnes infections. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effect of Antibiotic Therapy Before Arthrocentesis on Synovial Fluid Cell Count and Differential for Diagnosis of Native Joint Septic Arthritis.

We examined the effect of preoperative antibiotic exposure and duration on synovial fluid samples from patients with native joint septic arthritis of the hip/knee. While exposure before diagnostic arthrocentesis did not affect fluid parameters, increased duration was associated with a decreased total nucleated cell count, underscoring the complex antibiotic effects on synovial fluid parameters.

Effect of silica-sprayed collection tubes on synovial fluid bacterial culture.

Silica-sprayed tubes (SSTs) are often used to transport synovial fluid samples in equine practice. They promote the coagulation of the sample. The objective of the study is to evaluate the effect of SST on bacterial culture. The study was divided into two parts: sterile saline (Part A) and synovial fluid (Part B). Four common bacteria associated with equine synovial sepsis were used: Streptococcus pyogenes, Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Three collection tubes were used: STT, plain (no-additives) and brain and heart infusion (BHI) broth. Bacteria were cultured in horse blood agar plates for 48h. Outcome variables were negative culture, positive culture and total number of colony-forming units (CFUs). Statistical analysis was performed using Mann-Whitney U test, and significance was set at p<0.05. The total number of agar plates read was 1557 (779 saline; 778 synovial fluid). Total negative cultures were 25/779 on saline and 3/778 on synovial fluid. In broth, maximum growth CFU was achieved after 8h for both saline and synovial fluid for all bacteria. S. pyogenesand E. coli produced a significantly lower number of CFU when in SST compared to plain or broth after 4h, whereas S. aureus (American Type Culture Collection [ATCC] and MRSA) only after 24h. Silica-containing tubes reduced bacterial proliferation, whereas the use of a BHI broth provided the highest bacterial load in the sample. The use of SST may have a negative effect on bacterial proliferation in samples obtained from clinical cases.

Unveiling the Pathophysiology of Osteoarthritis in Joint Anatomy

Background: Osteoarthritis (OA) is a prevalent and debilitating joint disorder characterized by the degeneration of articular cartilage and underlying bone. Understanding the pathophysiology of OA is essential for developing targeted therapies and improving patient outcomes. Objective: To explore the underlying pathophysiological mechanisms of osteoarthritis within the context of joint anatomy, focusing on cartilage degradation, synovial inflammation, and subchondral bone changes. Methods: This prospective study was conducted at private hospitals in Karachi from June 2022 to December 2022. Eighty patients aged 45 to 70 years, diagnosed with OA, were included. Detailed clinical evaluations were performed, including pain assessment using the Visual Analog Scale (VAS) and functional status assessment using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Radiographic analysis was conducted using the Kellgren-Lawrence grading scale. Biochemical analysis of serum and synovial fluid was performed to measure levels of collagen type II cleavage products (C2C), cartilage oligomeric matrix protein (COMP), and inflammatory cytokines such as interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). Synovial fluid and tissue samples were collected during arthroscopy or joint replacement surgery for molecular pathway analysis. Data were analyzed using SPSS version 25, with correlations and regression analyses performed to identify predictors of disease progression. Results: OA was associated with significant pain and functional impairment, with a mean pain score of 7.2 ± 1.3 on the VAS and WOMAC scores averaging 55 ± 10 for physical function and 30 ± 5 for stiffness. Radiographic analysis showed 25% of patients classified as grade II, 50% as grade III, and 25% as grade IV. Biochemical markers indicated elevated levels of C2C (serum: 150 ± 20 ng/mL; synovial fluid: 200 ± 25 ng/mL) and COMP (serum: 10 ± 2 µg/mL; synovial fluid: 15 ± 3 µg/mL). Inflammatory cytokines were also elevated (IL-1β: 50 ± 5 pg/mL; TNF-α: 75 ± 10 pg/mL; IL-6: 100 ± 12 pg/mL). A strong positive correlation (r = 0.85, p &lt; 0.01) was observed between VAS pain scores and synovial IL-1β levels. Conclusion: The pathophysiology of osteoarthritis involves a complex interplay of biomechanical, biochemical, and cellular factors. The findings from this study enhance the understanding of OA mechanisms and provide a foundation for developing more effective therapeutic strategies aimed at halting or reversing the progression of OA.

Macrophage-Mimicking Cellular Nanoparticles Scavenge Proinflammatory Cytokines in Specimens of Patients with Inflammatory Disorders.

Effectively neutralizing inflammatory cytokines is crucial for managing a variety of inflammatory disorders. Current techniques that target only a subset of cytokines often fall short due to the intricate nature of redundant and compensatory cytokine networks. A promising solution to this challenge is using cell membrane-coated nanoparticles (CNPs). These nanoparticles replicate the complex interactions between cells and cytokines observed in disease pathology, providing a potential avenue for multiplex cytokine scavenging. While the development of CNPs using experimental animal models has shown great promise, their effectiveness in scavenging multiple cytokines in human diseases has yet to be demonstrated. To bridge this gap, this study selected macrophage membrane-coated CNPs (MФ-CNPs) and assessed their ability to scavenge inflammatory cytokines in serum samples from patients with COVID-19, sepsis, acute pancreatitis, or type-1 diabetes, along with synovial fluid samples from patients with rheumatoid arthritis. The results show that MФ-CNPs effectively scavenge critical inflammatory cytokines, including interleukin (IL)-6, IL-8, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, in a dose-dependent manner. Overall, this study demonstrates MФ-CNPs as a multiplex cytokine scavenging formulation with promising applications in clinical settings to treat a range of inflammatory disorders.

Clonal associations between lymphocyte subsets and functional states in rheumatoid arthritis synovium

Rheumatoid arthritis (RA) is an autoimmune disease involving antigen-specific T and B cells. Here, we perform single-cell RNA and repertoire sequencing on paired synovial tissue and blood samples from 12 seropositive RA patients. We identify clonally expanded CD4 + T cells, including CCL5+ cells and T peripheral helper (Tph) cells, which show a prominent transcriptomic signature of recent activation and effector function. CD8 + T cells show higher oligoclonality than CD4 + T cells, with the largest synovial clones enriched in GZMK+ cells. CD8 + T cells with possibly virus-reactive TCRs are distributed across transcriptomic clusters. In the B cell compartment, NR4A1+ activated B cells, and plasma cells are enriched in the synovium and demonstrate substantial clonal expansion. We identify synovial plasma cells that share BCRs with synovial ABC, memory, and activated B cells. Receptor-ligand analysis predicted IFNG and TNFRSF members as mediators of synovial Tph-B cell interactions. Together, these results reveal clonal relationships between functionally distinct lymphocyte populations that infiltrate the synovium of patients with RA.

Rapid differential diagnosis of periprosthetic joint infection by microdroplet reaction on portable biochip and indicator

Periprosthetic joint infection (PJI) is a catastrophic complication after joint arthroplasty. A key step to treat PJI is accurate diagnosis. However, according to the existing guidelines, no biomarker has been used to diagnose PJI alone and autoimmune diseases such as rheumatoid arthritis (RA) often interfere with the diagnosis. Patients with PJI often still face issues such as misdiagnosis and delayed treatment after a comprehensive scoring diagnosis. Thus, a rapid quantitative detection method based on excellent biomarker is needed. Here, an all-printed photonic crystal (PC) biochip is reported. Through the fluorescence enhancement effect of the photonic crystals and the design of the hydrophilic and hydrophobic patterning structure, trace detection of lactoferrin (LTF) in a drop of viscous synovial fluid can be achieved within 10 min by the biochip. The detection limit is as low as 4.6 ng/mL. For more intuitive results, portable testing equipment is developed with indicator light displays of three colors (green = NPJI, yellow = RA, and red = PJI) to indicate the diagnosis depending on the biochip’s fluorescence intensity. Furthermore, 79 clinical synovial fluid samples are tested with PC biochips, and the PC results are in good agreement with the ELISA results. Due to the microdroplet reaction on PCs, biochips are suitable for the detection of the selected markers in the synovial fluid. The use of the three-color portable testing equipment avoids the need for professional testing devices. Overall, this strategy provides a new paradigm for the early and differential diagnoses of PJI.