Role of inflammation in the pathogenesis of osteoarthritis: latest findings and interpretations

Effects of high impact exercise on systemic cytokines in women with mild knee osteoarthritis: A 12-month RCT

Objective

This study investigated the effects of a high-impact exercise regimen compared with a reference group on systemic cytokine levels in patients with mild knee osteoarthritis (OA). Furthermore, associations between cytokines and magnetic resonance imaging (MRI) transverse relaxation time (T2) mapping and metabolic equivalent task hours (MET-hours) during leisure-time physical activity (LTPA) were assessed.

Method

In this secondary analysis, 73 postmenopausal women aged 50-65 years with mild knee OA were randomized to a 12-month high-impact aerobic/step aerobics training group (n ​= ​35) or a non-training reference group (n ​= ​38). The serum cytokine levels, including interleukin-1 alpha (IL-1α), IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, IL-17, interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), were determined via multiplex cytokine assays. The cartilage structure of the medial tibial condyle was assessed by MRI T2 mapping. The primary outcome was between-group differences in cytokine level changes.

Results

After a 12-month follow-up, no significant differences in cytokine level changes were found between the groups. In the intervention group, 12-month changes in TNF-α levels were associated with changes in medial tibial condyle T2. In the reference group, 12-month changes in IL-10 levels were associated with changes in medial tibial condyle T2 and the number of weekly LTPA MET-hours.

Conclusion

A progressive high-impact exercise regimen did not affect systemic cytokine levels compared to the reference group and could therefore offer a possible mode of exercise for postmenopausal women with mild knee OA.

Trial registration number

ISRCTN58314639.

Rapgef3 modulates macrophage reprogramming and exacerbates synovitis and osteoarthritis under excessive mechanical loading

Evidence indicates that mechanical loading plays an important role in osteoarthritis (OA) progression, while the specific pathological changes of the synovium under excessive mechanical loading are unclear. Results showed that excessive mechanical loading caused pro-inflammation of synovial macrophages, which has been confirmed to exist in OA. High Rapgef3 expression level was found in RNA sequencing of RAW246.7 subjected to 0.5 Hz and 20% cyclic tensile strain. We verified this in the synovium of patients with OA and destabilization of the medial meniscus (DMM)-OA mice. Interestingly, the Rapgef3 content of chondrocytes was very low. Primary chondrocytes treated with Rapgef3 alone did not show metabolic phenotype, but an OA phenotype appeared when treated with Rapgef3-stimulated macrophage culture supernatant. Mechanically, excessive mechanical loading activated p65-nuclear factor κB (NF-κB) pathway through Rapgef3, which promoted the inflammation of macrophage, resulting in severe articular cartilage injury. Intra-articular Rapgef3 knockout reversed synovitis and cartilage degeneration, which might provide a therapeutic target for OA.

Targeted nanosome delivery of TPCA-1 for modulating inflammation in a mouse model of post-traumatic osteoarthritis

Inflammation plays a significant role in the pathogenesis of knee post-traumatic osteoarthritis (PTOA) characterized by damage to cartilage and surrounding tissues that results in loss of physiological function. This inflammation is mainly regulated by NF-κB pathway. The TPCA-1 can inhibit IκB kinase (IKK) β in NF-κB pathway. Here, we optimized the delivery of TPCA-1 to the damaged knee joint via targeted nanosomes and examined its effects in a mouse model of PTOA. PTOA was induced in mice through a modified cyclic mechanical loading method. Mice were divided into groups receiving vehicle, TPCA-1 solution, or TPCA-1-loaded nanosomes. A concentration of 100 μM TPCA-1 was used based on preliminary studies. Control groups included untreated and vehicle-treated animals. Treatment efficacy was assessed using in vivo imaging, serum biochemical assays, gene expression analysis of cartilage tissues, histopathology, and behavioral analysis. Mechanical loading induced significant knee joint damage in the model. TPCA-1 nanosomes notably attenuated the adverse effects of loading, outperforming both the vehicle and TPCA-1-solution in reducing inflammation. Notably, serum levels of total NO and LDH were significantly lower in the TPCA-1-nanosome group. Inflammation, as indicated by MMP13 and IL1β gene expression, was substantially reduced. Enhanced cartilage preservation and function were confirmed through IVIS imaging, histological assessments, and improved behavior metrics. The targeted delivery of TPCA-1 via nanosomes effectively inhibits the NF-κB pathway, leading to significant reductions in inflammation and cartilage damage in a PTOA mouse model. This strategy demonstrates potential as a therapeutic intervention for managing inflammation and preserving joint health in osteoarthritis.

Functionalized Biomimetic Nanoparticles Targeting the IL-10/IL-10Rα/Glycolytic Axis in Synovial Macrophages Alleviate Cartilage Degeneration in Osteoarthritis

Osteoarthritis (OA) is a low-grade inflammatory disease that is highly associated with severe hyperplasia of the synovial membrane and the degeneration of cartilage. Interleukin-10 (IL-10), has been extensively studied, while its receptor, IL-10Rα, has not been widely mentioned in the context of OA. A significant difference is found in the expression of IL-10Rα in synovial macrophages from normal and OA patients, along with a marked increase in the glycolytic activity of synovial macrophages. In IL-10RαLysm OA mice, the specific deficiency of IL-10Rα exacerbated the progression of OA. Mechanistically, hypoxia-inducible factor-1α (HIF-1α) is identified as a key transcription factor, and its inhibition significantly weakened the glycolytic process. Additionally, differences in ferroptosis of chondrocytes are observed. After co-culturing the two types of cells in vitro, a significant connection is found between the glycolytic state of synovial macrophages and the ferroptosis of chondrocytes. To achieve targeted therapy, MI@UN, a biomimetic nanoparticle encapsulating NO-prednisolone in UIO-66-NH2, surface-modified with IL-10, and coated with macrophage membranes (MM), is developed. It significantly slows osteoarthritis progression in mice. This offers new insights into OA pathogenesis, highlighting IL-10Rα as a therapeutic target and supporting MI@UN's translational use for OA treatment.

Phenotypic variations in knee osteoarthritis: insights from MRI and radiographic comparisons

OBJECTIVE

To investigate the correlation between MRI-based phenotypes (cartilage-meniscus, subchondral bone, and inflammatory) and radiography-based atrophic and hypertrophic phenotypes, aiming to demonstrate MRI's diagnostic capability in identifying complex osteoarthritis phenotypes that radiography cannot fully capture.

MATERIALS AND METHODS

This single-center retrospective study examined knee radiographs and MRIs of patients from November 2021 to April 2023 to identify osteoarthritis phenotypes. Radiographs were staged by the Kellgren-Lawrence system, and both modalities were classified into atrophic or hypertrophic phenotypes. MRIs were further classified into three phenotypes: cartilage-meniscus, subchondral bone, and inflammatory. Associations between phenotypes, Kellgren-Lawrence stage, age, and gender were analyzed with Pearson chi-square test and student T-test. Reliability measurements were evaluated using kappa statistic.

RESULTS

A total of 214 knees from 187 individuals (73.3% women, 26.7% men; mean age 57.1 ± 9.1 years) were included. The hypertrophic MRI phenotype was significantly associated with cartilage-meniscus and subchondral bone phenotypes (p < 0.001). Cartilage-meniscus and subchondral bone phenotypes were less prevalent in Kellgren-Lawrence stage 2 than in stages 3 and 4 (p < 0.001 and p = 0.004, respectively). The subchondral bone phenotype was more common in men (p = 0.022), and the cartilage-meniscus phenotype in the elderly (p < 0.001). Radiography and MRI had substantial agreement (Kappa = 0.637, p < 0.001) in diagnosing hypertrophic and atrophic phenotypes.

CONCLUSION

The hypertrophic phenotype was associated with cartilage-meniscus and subchondral bone phenotypes, with lower prevalences in Kellgren-Lawrence stage 2 knees. MRI offers enhanced phenotypic characterization, which facilitates more precise and individualized management in osteoarthritis care. Despite limitations compared to MRI, radiography remains valuable for the evaluation of hypertrophic and atrophic phenotypes.

Osteochondrosis in horses: An overview of genetic and other factors

Osteochondrosis (OC) is a frequent manifestation of developmental orthopaedic disease, and its severe clinical presentation is known as OC dissecans (OCD). OC is defined as a disruption of the endochondral ossification process in the epiphyseal cartilage, and this disease has been reported in different mammalian species, including humans, dogs, pigs, and horses. OCD is an important cause of lameness in sport horses and is a common cause of impaired orthopaedic potential, whose clinical signs may be of minimal magnitude or manifest as severe joint effusion or clinically noticeable lameness. The aetiology of OCD is unknown, although it has traditionally been considered to be multifactorial. In addition to genetic factors, associated factors include both non-genetic elements such as rapid growth, nutrition, trauma, anatomical conformation, and biomechanics. Since the prevalence of the disease varies greatly depending on the horse breed, from 13% in Swedish Warmblood to 53% in Lusitano breed, genetic factors have a great relevance in the appearance and development of OCD in horses. Many genetic modifications have been related, and the genes involved can be grouped into five clusters, related to fundamental functions for the correct development and regeneration of cartilage, such as collagen, laminin, cell signalling, matrix turnover, and transcriptional regulation. Changes in genes such as COL3A1, COL5A1, COL5A2, COL24A1, COL27A1 (collagen cluster), LAMB1 (laminin cluster), PTH, PHT receptors, and IHH (cell signalling), and genes encoding matrix metalloproteinases have been related to the occurrence and severity of diseases in different equine breeds. This review summarises the main factors associated with OC in horses, with particular emphasis on genetic factors.

Influence of dietary Saccharomyces cerevisiae fermentation product on markers of inflammation and cartilage metabolism in young exercising horses challenged with intra-articular lipopolysaccharide

The objective was to evaluate dietary Saccharomyces cerevisiae fermentation product (SCFP) on joint inflammation and cartilage metabolism in exercising yearlings challenged with intra-articular lipopolysaccharide (LPS), hypothesizing dietary SCFP (TruEquine®C, Diamond V Mills, Inc.) would ameliorate joint inflammation and increase cartilage metabolism. Thirty Quarter Horse yearlings were stratified by bodyweight (BW), age, sex, and randomly assigned to dietary treatments (n = 10/treatment): control (0), 46, or 92 mg/kg BW/d SCFP. Treatments were top-dressed to 1% BW/d concentrate void of added microbials. Horses were stalled (3.6 m × 7.3 m), offered ad libitum Coastal bermudagrass hay, and exercised 30 min/d, 5 d/wk. On days 0, 21, 42, and 56, wither height, hip height, heart girth, body length, body condition scores (BCS), and BW were recorded. On day 46, one radial carpal joint received 0.8 mL of a 0.5 ng LPS solution or sterile lactated Ringer's solution (LRS) in the contralateral joint. Synovial fluid was collected pre- (0) and 6, 12, 24, and 336 hours post-injection and analyzed for prostaglandin E2 (PGE2), carboxypropeptide of type II collagen (CPII), and collagenase cleavage neopeptide (C2C) via commercial ELISA, and chemokines (CCL2, and CCL11) and cytokines (TNF α and IL-10) via multiplex platform. Rectal temperature (RT), heart rate (HR), respiration rate (RR), and carpal circumference (CC) were recorded prior to arthrocentesis. Data were analyzed using PROC MIXED of SAS. By day 56, growth parameters increased (P < 0.01), BCS did not change (P = 0.39), and BW had a treatment × d interaction (P = 0.02) where control tended to be heavier than 92 mg/kg BW on day 56 (P = 0.07). Clinical parameters (RT, HR, RR, CC) were uninfluenced by diet (P ≥ 0.29) but varied over time (P ≤ 0.03). Treatments did not influence cartilage metabolism (CPII, C2C, and CPII:C2C) (P ≥ 0.46) or logPGE2, logCCL2, CCL11, or logIL-10 (P ≥ 0.23). There was a treatment × h interaction for CCL11 (P = 0.04) where control was greater than SCFP groups at h 6. LogIL-10 had a treatment × h interaction where 46 mg/kg BW was lower than control and 92 mg/kg BW at h 12 (P = 0.05). There was a main effect of treatment for TNF α (P = 0.04) where 92 mg/kg BW was lower than 46 mg/kg BW and tended to be lower than control. Results indicate that SCFP didn't influence cartilage metabolism or PGE2, though SCFP may ameliorate inflammatory cytokines and chemokines following an acute, intra-articular insult.

New mesenchymal stem/stromal cell-based strategies for osteoarthritis treatment: targeting macrophage-mediated inflammation to restore joint homeostasis

Macrophages are pivotal in osteoarthritis (OA) pathogenesis, as their dysregulated polarization can contribute to chronic inflammatory processes. This review explores the molecular and metabolic mechanisms that influence macrophage polarization and identifies potential strategies for OA treatment. Currently, non-surgical treatments for OA focus only on symptom management, and their efficacy is limited; thus, mesenchymal stem/stromal cells (MSCs) have gained attention for their anti-inflammatory and immunomodulatory capabilities. Emerging evidence suggests that small extracellular vesicles (sEVs) derived from MSCs can modulate macrophage function, thus offering potential therapeutic benefits in OA. Additionally, the transfer of mitochondria from MSCs to macrophages has shown promise in enhancing mitochondrial functionality and steering macrophages toward an anti-inflammatory M2-like phenotype. While further research is needed to confirm these findings, MSC-based strategies, including the use of sEVs and mitochondrial transfer, hold great promise for the treatment of OA and other chronic inflammatory diseases.

Carpaine ameliorates synovial inflammation by promoting p65 degradation and inhibiting the NF-κB signalling pathway

Aims

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

Methods

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

Results

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

Conclusion

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

Efficacy of Amniotic Suspension Allografts in the Treatment of Knee Osteoarthritis: A Systematic Review

Knee osteoarthritis significantly impacts mobility and quality of life. This condition is a leading cause of disability in aging populations, with total knee replacement commonly sought in advanced cases. Traditional nonoperative management strategies, including anti-inflammatories, corticosteroid injections, and hyaluronic acid, often provide limited relief, especially in severe cases. Recently, regenerative therapies such as amniotic suspension allografts (ASA) have emerged as promising alternatives due to their anti-inflammatory and regenerative properties, which may counteract the catabolic effects of osteoarthritis. This systematic review evaluated the efficacy and safety of ASA in reducing pain and improving function among knee osteoarthritis patients. Following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines, a comprehensive search of PubMed and Embase databases initially identified 1,733 studies pertaining to ASA, of which 1,575 were screened, and 9 studies ultimately met the inclusion criteria for detailed analysis of ASA in the treatment of knee osteoarthritis. Data extraction and narrative synthesis focused on outcomes such as pain reduction and functional improvement using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), as well as safety profiles. The results demonstrated notable improvements in pain scores following ASA treatment, as shown by studies reporting increases in KOOS pain scores over 6 months, which generally outperformed hyaluronic acid and saline treatments in pain reduction. Similarly, ASA treatment was associated with substantial improvements in physical function outcome scores, enhancing patients' ability to perform daily activities. Patient-reported outcomes also indicated higher quality of life and functional status, with most patients experiencing high levels of satisfaction. Additionally, ASA's safety profile was favorable, with adverse events primarily mild to moderate in nature, including a few transient events such as knee stiffness and myalgias. This systematic review highlights ASA as an effective therapeutic option for knee osteoarthritis, although further studies focusing on long-term radiographic outcomes and mechanisms of action are recommended to fully establish its benefits and optimize treatment protocols.

Intelligent Nanomaterials Design for Osteoarthritis Managements

Osteoarthritis (OA) is the most prevalent degenerative joint disorder, characterized by progressive joint degradation, pain, and diminished mobility, all of which collectively impair patients' quality of life and escalate healthcare expenditures. Current treatment options are often inadequate due to limited efficacy, adverse side effects, and temporary symptom relief, underscoring the urgent need for more effective therapeutic strategies. Recent advancements in nanomaterials and nanomedicines offer promising solutions by improving drug bioavailability, reducing side effects and providing targeted therapeutic benefits. This review critically examines the pathogenesis of OA, highlights the limitations of existing treatments, and explores the latest innovations in intelligent nanomaterials design for OA therapy, with an emphasis on their engineered properties, therapeutic mechanisms, and translational potential in clinical application. By compiling recent findings, this work aims to inspire further exploration and innovation in nanomedicine, ultimately advancing the development of more effective and personalized OA therapies.

Roles of innate immune system and receptor Dectin-1 in synovium and cartilage homeostasis of osteoarthritis

BACKGROUND

Innate immunity is crucial in the progression of osteoarthritis (OA); however, its mechanisms require further exploration. This study aims to investigate the mechanisms of innate immunity in OA synovitis.

METHODS

RNA sequencing data were analyzed to detect the expression characteristics of innate immunity-related genes in OA synovium. The Search Tool for the Retrieval of Interaction Gene/Proteins (STRING) database was used to identify hub genes, and an OA diagnostic model was constructed using 113 combinations of machine learning algorithms. Single-cell sequencing data were used to identify the expression patterns of hub genes and innate immunity-related pathways in cell clusters and to illustrate the interactions among cell populations. The functional mechanism of Dectin-1 in OA was validated experimentally.

RESULTS

Innate immunity-related genes and pathways were significantly expressed in the synovium of patients with OA. We constructed an OA diagnostic model, and HLA-DRA+ cells were identified as a critical cell population. The innate immune receptor Dectin-1 on macrophages regulated macrophage M1 polarization and cartilage homeostasis via the Dectin-1/Syk/NF-κB pathway, influencing the progression of OA.

CONCLUSION

This study reveals the expression patterns of innate immunity-related genes and pathways in the OA synovium and highlights the role of Dectin-1 in macrophages.

Metformin as a disease-modifying therapy in osteoarthritis: bridging metabolism and joint health

Background

Osteoarthritis (OA) and impaired glucose tolerance (IGT) frequently coexist, leading to compounded clinical and metabolic challenges. This study investigates the effects of metformin in improving both clinical outcomes (pain, stiffness, physical function) and metabolic parameters (inflammatory markers, lipid profile, BMI) in patients with knee OA and IGT.

Methods

The study included 60 patients diagnosed with knee OA and IGT. Participants were divided into two groups: 26 patients received standard OA treatment without metformin (Without Metf), while 34 received metformin (500 mg twice daily) for 3 months, in addition to standard treatment (With Metf). Clinical assessments (WOMAC, Lequesne Algofunctional Index, KOOS, VAS) and metabolic markers (CRP, NLR, SOD, lipid profile, BMI) were measured before treatment, after 1 month, and after 3 months.

Results

The With Metf group showed significantly greater improvements in pain, stiffness, physical function, and quality of life compared to the Without Metf group. Metformin also led to significant reductions in inflammatory markers and improvements in lipid profiles and metabolic health indicators. The With Metf group demonstrated enhanced BMI, waist-to-hip ratio, and waist-to-height ratio. Furthermore, the need for increased NSAID doses was predicted by factors such as pain severity and inflammatory markers.

Conclusion

Metformin effectively alleviates osteoarthritis symptoms and improves metabolic health in patients with both OA and IGT. Further research is needed to explore its long-term effects on joint health, inflammatory markers, and its potential role in OA management in patients without IGT.

The comparative efficacy of L-glutamine, celecoxib, and glucosamine sulfate in osteoarthritis management

To explore the therapeutic efficacy of L-glutamine (L-Gln) on pathological progression and clinical symptoms of osteoarthritis (OA), and compare with glucosamine sulfate (GS), and celecoxib (CXB). Rats were administered sodium chloride, L-Gln, GS, or CXB via gavage for eight weeks starting from the fifth week after sham operation or Anterior Cruciate Ligament Transection (ACLT) + Medial Meniscectomy (MMx). Then the severity of knee OA in rats was evaluated by serological analysis, histological examination and imaging examination. In addition, patients with mild primary OA were administered L-Gln, GS, or CXB orally for 12 weeks in accordance with the randomization principle. The efficacy end points were the change from baseline to week 24 in the pain and physical function subscale scores of the Western Ontario and McMaster Universities OA Index (WOMAC), and Lequesne score. Treatment with L-Gln alleviated the increased concentration of serum cartilage degradation markers caused by OA in rats. Histological tests showed improvement in knee joint cartilage destruction after treatment. Three-dimensional CT scans and reconstructions revealed a reduction in osteophyte formation and subchondral bone loss. L-glutamine performed as well as or better than glucosamine sulfate and celecoxib in all comparative measures among the three treatment groups. In clinical trials, the WOMAC pain and physical function subscale scores, as well as the Lequesne score, decreased from baseline in all three patient groups during follow-up, with no significant differences observed between the groups. Our research indicates that L-Gln is comparable to GS and CXB in improving the pathological progression and clinical efficacy of OA, which makes it a promising drug for the treatment of osteoarthritis.

Free Radical Scavenging Activity and Inhibition of Enzyme-Catalyzed Oxidation by trans-aryl-Palladium Complexes

Herein, nine square planar trans-arylbis(triphenylphosphine)palladium halides (PdX(PPh3)2Ar) were synthesized and fully characterized. The molecular structure of two complexes (1 and 2) have been determined by both X-ray diffraction and described thanks to Hirshfeld surface analysis. Investigation of the antioxidant activities showed that most of the complexes exhibit a strong dose-dependent radical scavenging activity towards DPPH radical as well as in the ABTS radical scavenging test. Complexes 1 [PdI(PPh3)2(4-MeOC6H4)] and 3 [PdCl(PPh3)2(4-MeOC6H4)] showed the highest activity in the DPPH assay with EC50 values of 1.14 ± 0.90 and 1.9 ± 0.87 µM, respectively. In contrast, for the ABTS assay, quercetin (5.56 ± 0.97 µM) was slightly more efficient than the three complexes 1 (5.78 ± 0.98 µM), 2 (7.01 ± 0.98 µM), and 3 (11.12 ± 0.94 µM). The use of kinetic studies as a powerful parameter shows that complexes 1, 2, and 3 displayed the best antioxidant efficiency. The antioxidant effect of the nine palladium complexes has been also evaluated on the enzyme-catalyzed oxidation of the L012 probe (using HRP/H2O2) by using a chemiluminescence technique. As with the last model, complexes 1, 2, and 3 showed the best activity, with EC50 values of 3.56 ± 1.87, 148 0.71, and 5.8 ± 2.60 µM, respectively. Interestingly, those complexes (1, 2, and 3) even exhibited a higher dose-dependent activity than the quercetin (7.06 ± 2.56 µM) used as a standard. Taken together, the combined results reveal that the antiradical and enzyme (HRP) inhibitory activity of complexes decrease following the ligand order of p-OMePh > p-OAcPh >> Ph.

Insulin-Like Growth Factor 2 Secreted from Mesenchymal Stem Cells with High Glutathione Levels Alleviates Osteoarthritis via Paracrine Rejuvenation of Senescent Chondrocytes

Senescent chondrocytes, which are increased in osteoarthritic (OA) cartilage, promote cartilage defects and the senescent knee microenvironment by inducing senescence to surrounding normal chondrocytes by secreting senescence-associated secretory proteins. Many studies have used mesenchymal stem cells (MSCs) to treat OA, but MSC treatment remains challenging for clinical application owing to MSC quality control, engraftment, and fibrocartilage regeneration. Here, rather than relying on the direct regeneration of MSCs, we present a novel strategy to suppress OA by MSC-mediated senescent chondrocyte targeting via the paracrine activity of MSCs, thereby improving the knee microenvironment. First, to enable quality control of umbilical cord MSCs, priming MSCs by supplementing human platelet lysate (hPL) greatly enhanced MSC functions by increasing cellular glutathione levels throughout serial passaging. Intra-articular injection of primed MSCs successfully suppressed OA progression and senescent chondrocyte accumulation without direct regeneration. Indirect coculture with primed MSCs using transwell ameliorated the senescence phenotypes in OA chondrocytes, suggesting paracrine rejuvenation. Based on secretome analysis, we identified insulin-like growth factor 2 (IGF2) as a key component that induces paracrine rejuvenation by primed MSCs. The rejuvenation effects of IGF2 act through autophagy activation through the up-regulation of autophagy-related gene expression and autophagic flux. To cross-validate the effects of secreted IGF2 in vivo, knockdown of IGF2 in primed MSCs substantially abolished its therapeutic efficacy in a rabbit OA model. Collectively, these findings demonstrate that hPL supplementation enables MSC quality control by increasing MSC glutathione levels. The therapeutic mechanism of primed MSCs was secreted IGF2, which induces paracrine rejuvenation of senescent OA chondrocytes by activating autophagy.

Multiple Intra-Articular Injections of Adipose-Derived Mesenchymal Stem Cells for Canine Osteoarthritis Treatment

Osteoarthritis (OA) is one of the most common degenerative diseases in dogs and humans, which can lead to articular cartilage deterioration, chronic pain, and decreased quality of life. The anti-inflammatory, anti-fibrotic, analgesic, and cartilage regeneration properties of mesenchymal stem cell (MSC) therapy provide a new direction for the treatment development of OA in the future. Currently, MSC therapy lacks confirmed ideal sources, dosages, formulations, and specific characteristics. In this study, we evaluated the efficacy of multiple canine adipose-derived mesenchymal stem cell (ADSC) injections on anti-inflammation and joint cartilage damage in a canine OA model. Considering animal ethics, we simulated the effects of inflammation and cartilage repair during treatment through a mouse OA model. In the mouse OA model, through the detection of cartilage repair and inflammation-related key factors via histology and molecular biology, it was found that MSC therapy has a certain repair effect on cartilage, but the anti-inflammatory effect is time-dependent. In the canine OA model, we verified the feasibility of multiple injections of ADSCs. Compared with the control group, the cartilage repair effect of the treatment group was obvious, and the inflammatory factors decreased, showing an obvious therapeutic effect. This study demonstrates that multiple intra-articular injections of canine ADSCs could be effective in treating OA symptoms.

A Narrative Review on Manufacturing Methods Employed in the Production of Mesenchymal Stromal Cells for Knee Osteoarthritis Therapy

Knee osteoarthritis (OA) is a chronic, progressive, inflammatory, and degenerative whole-joint disease. Early-stage OA treatments typically include physiotherapy, weight-loss, pain relief medications, and intra-articular knee injections, such as corticosteroids, hyaluronic acid, or platelet-rich plasma. These treatments primarily provide symptomatic relief rather than reversing or halting disease progression. Recently, mesenchymal stromal cell (MSC) injections have garnered attention due to their immunomodulatory and regenerative capacities. MSCs, which can be derived from sources such as bone marrow, umbilical cord, or adipose tissue, and can be allogeneic or autologous, have demonstrated promising results in both animal models and several human studies. However, different protocols have been employed, presenting challenges for comparing outcomes. In this review, we address these variable settings, evaluate current practices, and identify key factors critical in optimizing MSC-based therapies by critically reviewing clinical trials of ex vivo expanded MSC therapies for OA undertaken between 2008 and 2023. Specific attention was given to two key aspects: (1) the cell culture process employed in manufacturing of autologous or allogeneic MSC products, and (2) the post-culture methods employed in storage, reconstitution and administration of the MSCs. Our findings suggest that standardizing MSC production for clinical applications remains a significant challenge, primarily due to variations in tissue sources, harvesting techniques, and manufacturing protocols, and due to broad discrepancies in reporting. Thus, we propose a set of minimal reporting criteria to guide future clinical trials. A common reporting guideline is a critical step towards a more standardized MSC production across different laboratories and clinical settings, thereby enhancing reproducibility and advancing the field of regenerative medicine for knee OA, as well as other disease settings.

Transcriptomic analysis of human cartilage identified potential therapeutic targets for hip osteoarthritis

Cartilage degradation is the hallmark of osteoarthritis (OA). The purpose of this study was to identify and validate differentially expressed genes (DEGs) in human articular cartilage that could serve as potential therapeutic targets for hip OA. We performed transcriptomic profiling in a discovery cohort (12 OA-free and 72 hip OA-affected cartilage) and identified 179 DEGs between OA-free and OA-affected cartilage after correcting for multiple testing (P < 2.97 × 10-6). Pathway and network analyses found eight hub genes to be associated with hip OA (ASPN, COL1A2, MXRA5, P3H1, PCOLCE, SDC1, SPARC, and TLR2), which were all confirmed using qPCR in a validation cohort (36 OA-free and 62 hip OA-affected cartilage) (P < 6.25 × 10-3). Our data showed that dysregulation of extracellular matrix formation and imbalance in the proportion of collagen chains may contribute to the development of hip OA, and SDC1 could be a promising potential therapeutic target. These findings provided a better understanding of the molecular mechanisms for hip OA and may assist in developing targeted treatment strategies.

The eFEct of an Anti-Inflammatory Diet for Knee oSTeoarthritis (FEAST) Trial: Baseline Characteristics and Relationships With Dietary Inflammatory Index

OBJECTIVE

This study aims to: (i) describe the results of recruitment into the eFfEct of an Anti-inflammatory diet for knee oSTeoarthritis (FEAST) randomized controlled trial (RCT); (ii) report baseline characteristics of randomized participants and compare these with four large international cohorts; and (iii) explore cross-sectional associations between dietary inflammatory index (DII®) scores and baseline clinical characteristics.

METHODS

The FEAST RCT compares an anti-inflammatory dietary programme and standard care low-fat dietary programme for adults aged 45-85 years with knee osteoarthritis (OA). At baseline, participants provided medical history (medical comorbidities, symptomatic musculoskeletal sites), completed questionnaires (demographic characteristics, Knee injury and OA Outcome Score (KOOS)) and a 3-day food diary. Both DII® and energy-adjusted DII (E-DIITM) scores were calculated based on 3-day food diary data and was used to quantify the effect of diet on systemic inflammation. Associations between DII/E-DII and KOOS subscales, symptomatic musculoskeletal sites, and comorbidities was assessed using linear and negative binomial regression.

RESULTS

1121 individuals were screened to identify 182 eligible individuals, from which 144 participants (64% female, 36% male) enrolled, with a mean ± SD age 65 ± 8 years and body mass index 30.3 ± 6.2 kg/m2. Overweight (41%) and obesity (45%) was common. Two-thirds (62%) had ≥1 medical comorbidity, most commonly hypertension (26%). Musculoskeletal pain in sites other than the index knee was reported in 79%, most commonly in the lower back (42%). Mean DII and E-DII scores were 0.58 ± 1.49 and -0.31 ± 1.41, respectively. No associations were found between DII/E-DII and KOOS subscales except for activities of daily living (ADL), number of medical comorbidities and symptomatic MSK sites, and BMI.

CONCLUSION

The FEAST cohort is comparable to other knee OA cohorts, supporting generalizability of the results. Despite a relatively pro-inflammatory diet at baseline, DII/E-DII was not associated with KOOS subscales, number of comorbidities or symptomatic musculoskeletal sites.

GAS5 long non-coding RNA interacts with microRNA-205 to relieve fibroblast-like synoviocyte inflammation and ferroptosis in osteoarthritis

This study aimed to explore the role of the growth arrest-specific five gene (GAS5) long non-coding RNA (lncRNA) in fibroblast-like synoviocytes (FLSs) during the development of osteoarthritis (OA). A total of 25 OA synovial tissues and nine healthy control tissues were collected, and their GAS5 expression was compared. To confirm GAS5 expression in vitro, interleukin (IL)-1β was used to mimic a cellular OA model based on isolated FLSs. Quantitative polymerase chain reaction revealed higher expression levels of GAS5 in OA samples than in non-OA samples. In vitro, the stimulation of FLSs by IL-1β induced high GAS5 expression. The IL-1β-exposed cells exhibited impaired growth, viability, and antioxidant capacity, as well as increased cell death, production of cellular and lipid ROS, and inflammatory cytokine levels. The expression levels of ferroptosis-related proteins in FLSs were also altered in IL-1β-exposed cells. GAS5 was observed to directly target and inhibit micro-RNA 205, partially reversing the effect of GAS5 silencing on cell proliferation, cell death, oxidative stress, inflammation, and FLS ferroptosis. FLS ferroptosis is recognized to be involved in OA development, and the downregulation of the GAS5 lncRNA exhibits protective effects by suppressing ferroptosis and sponging miR-205 in FLSs in OA, thereby providing a novel strategy for the treatment of OA. The GAS5-miR-205 axis can regulate inflammation and oxidative stress in the FLSs of patients with OA.

Transarterial Embolization for Musculoskeletal Pain Management: AJR Expert Panel Narrative Review

Musculoskeletal embolization has emerged in recent years as a treatment of chronic joint pain, as the inflammatory cascade responsible for such pain has become better understood. Studies have shown a complex interplay between joint inflammation and synovial hypervascularity that causes growth of new unmyelinated nerve fibers responsible for pain. Embolization targets joint hypervascularity to disrupt the inflammatory cycle and provide pain relief. The standard treatment algorithm for chronic joint pain is well established and entails escalating therapeutic options that include exercise, self-management programs, analgesic medications, intraarticular injections, and finally surgical replacement or release. Genicular artery embolization (GAE), targeting abnormal vasculature around the knee joint, is the most studied musculoskeletal embolization procedure, reflecting the high worldwide prevalence and increasing incidence of knee osteoarthritis (OA). GAE is now supported by multiple prospective studies, including randomized controlled trials comparing GAE versus sham treatment. Embolization has also extended outside of the knee joint to include the shoulder (treatment of adhesive capsulitis or secondary stiff shoulder), elbow (medial or lateral epicondylitis), hip (OA, great trochanteric pain syndrome), and ankle (plantar fasciitis). This AJR Expert Panel Narrative Review discusses the current status of transarterial embolization for musculoskeletal pain management, focusing on treatment of knee OA and chronic shoulder pain.

MR Imaging of the Hip: Infectious and Inflammatory Conditions

MR imaging is a useful tool in establishing the diagnosis of inflammation and/or infection in the hip joint and adjacent tissues, and in determining the extent of disease. In conjunction with clinical factors, MR imaging findings can help to narrow the differential diagnosis in individual cases and can guide decisions regarding biopsies, aspirations, or additional imaging.

Identification of WDR74 and TNFRSF12A as biomarkers for early osteoarthritis using machine learning and immunohistochemistry

Background

Osteoarthritis (OA) is a chronic joint condition that causes pain, limited mobility, and reduced quality of life, posing a threat to healthy aging. Early detection is crucial for improving prognosis. Recent research has focused on the role of ubiquitination-related genes (URGs) in early OA prediction. This study aims to integrate URG expression data with machine learning (ML) to identify biomarkers that improve diagnosis and prognosis in the early stages of OA.

Methods

OA single-cell RNA sequencing datasets were collected from the GEO database. Single-cell analysis was performed to investigate the composition and relationships of chondrocytes in OA. The potential intercellular communication mechanisms were explored using the CellChat R package. URGs were retrieved from GeneCards, and ubiquitination scores were calculated using the AUCell package. Gene module analysis based on co-expression network analysis was conducted to identify core genes. Additionally, ML analysis was performed to identify core URGs and construct a diagnostic model. We employed XGBoost, a gradient-boosting ML algorithm, to identify core URGs and construct a diagnostic model. The model's performance was evaluated using the area under the curve (AUC) of the receiver operating characteristic (ROC) curve. In addition, we explored the relationship between core URGs and immune processes. The ChEA3 database was utilized to predict the transcription factors regulated by core ubiquitination-related genes. The expression of select URGs was validated using qRT-PCR and immunohistochemistry (IHC).

Results

We identified WDR74 and TNFRSF12A as pivotal ubiquitination-related genes associated with OA, exhibiting considerable differential expression. The diagnostic model constructed with URGs exhibited remarkable accuracy, with area under the curve (AUC) values consistently exceeding 0.9. The expression levels of WDR74 and TNFRSF12A were significantly higher in the IL-1β-induced group in an in vitro qPCR experiment. The IHC validation on human knee joint specimens confirmed the upregulation of WDR74 and TNFRSF12A in OA tissues, corroborating their potential as diagnostic biomarkers.

Conclusions

WDR74 and TNFRSF12A as principal biomarkers highlighted their attractiveness as therapeutic targets. The identification of core biomarkers might facilitate early intervention options, potentially modifying the illness trajectory and enhancing patient outcomes.

Associations between neutrophil percentage to albumin ratio and rheumatoid arthritis versus osteoarthritis: a comprehensive analysis utilizing the NHANES database

Objectives

The association between the neutrophil percentage to albumin ratio (NPAR) and the risk of osteoarthritis (OA) and rheumatoid arthritis (RA) remains unclear. This study aims to investigate the association between NPAR and the risk of OA and RA.

Methods

This cross-sectional study analyzed data from 92,062 American adults in the NHANES database between 1999 and 2016. Various statistical analyses were conducted to investigate the associations between NPAR and the risks of OA and RA, including multivariable logistic regression, subgroup analysis, smooth curve fitting, and threshold effect analysis.

Results

After screening, the final study population included 36,147 participants, with 3,881 individuals diagnosed with OA and 2,178 with RA. After adjusting for confounding factors, higher NPAR levels were associated with an increased risk of RA (OR=1.05; 95% CI: 1.03-1.07; P <0.0001), but not with OA (OR=1.01; 95% CI: 0.99-1.02; P =0.755). This association was remarkably consistent across subgroups by age, sex, body mass index (BMI), alcohol consumption, hypertension, diabetes, and smoking status. Further analyses using curve fitting and threshold effect models revealed a nonlinear association between NPAR and RA, with an inflection point identified at 15.56.

Conclusion

High levels of NPAR is positively associated with the prevalence of RA. This provides us with new insights for the management and treatment of RA patients.

Evaluating the Anti-Inflammatory and Chondroprotective Effects of Adenocaulon himalaicum Extract Through Network Pharmacology and Experimental Validation

Conventional osteoarthritis treatments have several side effects and poor efficacy. This study explored the anti-inflammatory and cartilage-protective effects of Adenocaulon himalaicum, with a focus on its potential application in osteoarthritis treatment. The anti-inflammatory effects of A. himalaicum extract (AHLE) were investigated in lipopolysaccharide-induced RAW264.7 macrophages, interleukin (IL)-1β-stimulated chondrocytes, and rats with carrageenan-induced hind paw oedema. We also evaluated AHLE's analgesic activity in mice with acetic acid-induced writhing. The components of AHLE were subjected to network pharmacological analysis to elucidate their mechanisms of action and validate potential pathways and targets in vitro. AHLE markedly reduced nitric oxide, IL-1β, IL-6, tumour necrosis factor-alpha, and prostaglandin E2 production in both RAW264.7 macrophages and chondrocytes. In animal models, AHLE reduced carrageenan-induced hind paw swelling and provided analgesic effects in writhing tests. The main components were chlorogenic acid; 1,3-dicaffeoylquinic acid; 3,4-dicaffeoylquinic acid; 3,5-dicaffeoylquinic acid; and 4,5-dicaffeoylquinic acid. According to network pharmacological analysis, AHLE's main therapeutic targets are the mitogen-activated protein kinase (MAPK) signalling pathway and extracellular matrix (ECM) degradation. These targets were verified through the MAPK pathway and expression of matrix metalloproteinase, an enzyme involved in ECM degradation. In conclusion, AHLE has considerable anti-inflammatory and cartilage-protective properties, making it a promising candidate for osteoarthritis therapy.

TMJ Replacement in Degenerative Disease: A Systematic Review

Objectives: This study aims to describe and analyze the indications and clinical results of total TMJ replacement in participants with degenerative and/or inflammatory joint diseases, defining patient and intervention conditions. Methods: A systematic review was conducted according to the Cochrane Handbook for Systematic Reviews of Intervention and reported according to the PRISMA Items update. The search strategy was from 1997 to July 2024 in Pubmed, Embase, Scopus, and Web of Science. A search for gray literature was conducted in the databases Google Scholar and Open Access Theses and Dissertations (OATD), and there were no limitations on the language or study design. We incorporated studies involving human patients over 15 years of age with degenerative and/or inflammatory joint conditions who underwent joint prosthesis replacement, either concurrently or separately from orthognathic surgery, as an initial intervention or after prosthesis installation. Participants with a postoperative follow-up of 12 months or longer were included. A risk of bias analysis was performed for non-randomized studies using the ROBINS-I tool, and GRADE profiler (GRADEpro) software was used to assess the quality of evidence and synthesize the data. Results: All the selected studies performed postoperative follow-up with quantitative and qualitative parameters; 10 performed a follow-up of 2 to 5 years. The indication for joint prosthesis replacement due to system failure was only 4.07%. Concerning diagnoses, 579 presented degenerative and/or inflammatory joint diseases, with osteoarthritis being the most frequent, followed by osteoarthrosis, juvenile idiopathic arthritis, and rheumatoid arthritis. The maximum mouth opening of the participants with TMJ disease presented an average of 24.32 ± 5.8 mm with a range of 18 to 36.4 mm. Of the 579 participants, the studies mention that they presented a soft to liquid diet and pain associated with decreased mandibular functionality. Conclusions: A total of 76.18% of the participants presented a range of moderate to severe pain associated with a decrease in functionality and, after joint replacement, all participants mentioned a decrease in pain or absence of pain, a change in diet by incorporating solid foods, and an increase in opening with an average of 40.74 ± 3.1 mm. Total joint replacement shows favorable long-term results. It is not possible to identify the best time to perform joint replacement surgery, considering the time since diagnosis of the disease, the time since the start of non-surgical treatment, or the number of previous surgeries.

Terminal complement complex deposition on chondrocytes promotes premature senescence in age- and trauma-related osteoarthritis

Background

The complement system is locally activated after joint injuries and leads to the deposition of the terminal complement complex (TCC). Sublytic TCC deposition is associated with phenotypical alterations of human articular chondrocytes (hAC) and enhanced release of inflammatory cytokines. Chronic inflammation is a known driver of chondrosenescence in osteoarthritis (OA). Therefore, we investigated whether TCC deposition contributes to stress-induced premature senescence (SIPS) during aging in vivo and after ex vivo cartilage injury.

Methods

Femoral condyles of male 13-week-old and 72-week-old CD59-ko (higher TCC deposition), C6-deficient (insufficient TCC formation), and C57BL/6 (WT) mice were collected to assess age-related OA. Furthermore, macroscopically intact human and porcine cartilage explants were traumatized and cultured with/without 30% human serum (HS) to activate the complement system. Explants were additionally treated with clusterin (CLU, TCC inhibitor), N-acetylcysteine (NAC, antioxidant), Sarilumab (IL-6 receptor inhibitor), STAT3-IN-1 (STAT3 inhibitor), or IL-1 receptor antagonist (IL-1RA) in order to investigate the consequences of TCC deposition. Gene and protein expression of senescence-associated markers such as CDKN1A and CDKN2A was determined.

Results

In the murine aging model, CD59-ko mice developed after 72 weeks more severe OA compared to C6-deficient and WT mice. mRNA analysis revealed that the expression of Cdkn1a, Cdkn2a, Tp53, Il1b, and Il6 was significantly increased in the cartilage of CD59-ko mice. In human cartilage, trauma and subsequent stimulation with HS increased mRNA levels of CDKN1A, CDKN2A, and IL6, while inhibition of TCC formation by CLU reduced the expression. Antioxidative therapy with NAC had no anti-senescent effect. In porcine tissue, HS exposure and trauma had additive effects on the number of CDKN2A-positive cells, while Sarilumab, STAT-IN-1, and IL-1RA reduced CDKN2A expression by trend.

Conclusion

Our results demonstrate that complement activation and consequent TCC deposition is associated with chondrosenescence in age-related and trauma-induced OA. We provided evidence that the SIPS-like phenotype is more likely induced by TCC-mediated cytokine release rather than oxidative stress. Overall, targeting TCC formation could be a future approach to attenuate OA progression.

Immunomodulation Effects of Porcine Cartilage Acellularized Matrix (pCAM) for Osteoarthritis Treatment

BACKGROUND

Pain reduction, immunomodulation, and cartilage repair are key therapeutic goals in osteoarthritis (OA) treatment. In this study, we evaluated the therapeutic effects of porcine cartilage acellularized matrix (pCAM) derived from naive tissue and compared it with the synthetic material polynucleotides (PN) for OA treatment.

METHODS

pCAM was produced from porcine cartilage through physicochemical processing. LC-MS protein profiling identified the key proteins. In vitro experiments involved treating human synovial cell with pCAM and PN to assess cell viability and reductions in pro-inflammatory cytokines (IL-1β and IL-6). In vivo studies utilized a rat DMM-induced OA model. Pain was evaluated in weight-bearing tests, and inflammation reduction was confirmed using specific macrophage markers of CD68, CD86, and CD163 in immunohistochemical staining of synovial tissue. Cartilage regeneration was evaluated by histopathological analyses.

RESULTS

The major protein components of pCAM include factors integral to cartilage and ECM integrity. They also contain proteins that help reduce inflammation. In vitro studies revealed a decrease in pro-inflammatory cytokines and survival of synovial cells were observed. In vivo treatment with pCAM resulted in a reduction of pain and inflammation, while promoting cartilage regeneration, thereby accelerating the healing process in OA.

CONCLUSION

Our findings suggest that pCAM may contribute to the treatment of OA by alleviating synovial inflammation and supporting cartilage regeneration, thereby addressing both the inflammatory and degenerative aspects of the disease.

Comparison of Maitland Passive Joint Mobilization and Self-Rehabilitation on Function, Activity, and Quality of Life in Beninese Patients With Hip Osteoarthritis: A Pragmatic Randomized Trial

BACKGROUND

Orthopedic manual therapy is currently considered as an alternative approach for treating hip osteoarthritis. However, studies assessing its efficacy in low-income countries in Sub-Saharan Africa are scarce.

OBJECTIVES

Investigating the effectiveness of Maitland passive joint mobilization (Maitland PJM) compared to self-rehabilitation in patients with hip osteoarthritis in Benin, a low-income country, in Sub-Saharan Africa.

METHODS

This was a pragmatic, single-blind, two-arm randomized trial involving 66 participants randomly assigned into two groups (Maitland PJM group, n = 33, and self-rehabilitation group, n = 33). Both interventions took 5 weeks. The primary outcome (pain) was evaluated using numerical rating scale. Secondary outcomes (passive hip range of motion, muscles strength, walking, and quality of life) were assessed using goniometry, medical research council, 10 m walk test, and short-form 36. Participants were assessed at baseline, after interventions and 3-month follow-up.

RESULTS

Forty-nine patients (Maitland PJM group, n = 22, self-rehabilitation, n = 27) completed the sessions. Within-group analyses showed a significant improvement in body function, walking speed, and quality of life (p < 0.05) after interventions and at 3-month follow-up within both groups. No significant differences in any outcomes were observed between the Maitland PJM and self-rehabilitation groups, after interventions and at the 3-month follow-up (p > 0.05).

CONCLUSION

Maitland passive joint mobilization and self-rehabilitation similarly improved function, walking speed, and quality of life in Beninese patients with hip osteoarthritis.

TRIAL REGISTRATION

PACTR201911553990405.

Interplay of calcium pyrophosphate crystals, oxidative stress, and clinical features on knee osteoarthritis severity

BACKGROUND

Deposition of calcium pyrophosphate (CPP) crystals is observed in most joints affected by severe osteoarthritis (OA). CPP may cause local damage by inducing an inflammatory process and oxidative stress (OS).

OBJECTIVES

To evaluate inflammation and OS induced by CPP deposition and their association with the degree of knee OA.

METHODS

Synovial fluid (SF) from patients with OA classified as grade 3 and 4 (ACR criteria) was analyzed. Reactive oxygen species (ROS) and H2O2 levels were quantified, and inflammation by white blood cell (WBC) count. CPPs were detected by polarized light microscopy. Multifactorial dimensionality reduction (MDR) was used to visualize possible interactive effects between variables.

RESULTS

Fifty-six SF were analyzed, 22 (39.28%) were in moderate OA and 34 (60.71%) in severe OA. CPPs were identified in 17 moderate OA and 18 severe OA samples. In the moderate OA, ROS levels were significantly higher in the CPP + group (5.0% vs 2.0%, P = 0.03). Body mass index and CPP were significantly correlated (r =  - 0.439, P = 0.041). In the severe OA group, there were significant correlations of age with WBC (r =  - 0.431, P = 0.011), WBC with H2O2 (r = 0.454, P = 0.007), and ROS with H2O2 (r = 0.387, P = 0.024). MDR analysis revealed strong synergistic interactions between H2O2 and sex (6.68%) for moderate OA, while for severe OA, there were interactions between sex and ROS (6.99%) and between sex and inflammation (4.39%).

CONCLUSION

ROS and inflammation may be factors that potentiate damage in knee OA, and this may help in the development of antioxidant interventions for CPP-associated OA. Key Points • This study evaluated CPP crystal-induced oxidative stress and inflammation and their effect on OA severity. • In the moderate OA phenotype, CPP crystals modify ROS levels. • ROS and inflammation are factors that increase damage in knee OA, especially when CPP crystals are present.

Differential Expression of Fibrinogen Alpha and Its Potential Involvement in Osteoarthritis Pathogenesis

The deterioration of cartilage tissue and other joint components composed of synovial tissue is a defining characteristic of osteoarthritis (OA) disease. Because of the lack of understanding of the underlying cause and important molecular pathways, there are currently no effective diagnostic or treatment methods for OA. The purpose of the study is to find a specific protein biomarker with high sensitivity and specificity in order to understand the pathophysiology of the disease and the underlying molecular pathways. We examined plasma samples of matched age and sex from OA patients (n = 150) and healthy controls (HC) (n = 70) to find proteins that were differentially expressed and validated by western blotting, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and immunofluorescence. The results of western blotting demonstrated that the expression level of the fibrinogen alpha (FGA) protein was higher in plasma samples of osteoarthritis (OAPL) (p = 0.0343), and the ROC (receiver operating characteristic curve) curve supported the high sensitivity (95.22%) and specificity (74%) of FGA in OA plasma compared to healthy controls. FGA protein was detected to be deposited in the synovial tissue of OA patients (p = 0.0073). By activating the Toll-like receptor (TLR-4) receptor pathway in PBMCs (p = 0.04) and synovial tissue, FGA protein may be involved in the molecular mechanism of OA pathogenesis. Our findings collectively suggested that FGA, which is significantly expressed in OA plasma, synovial tissue, and PBMCs and is connected to the disease's advancement through the TLR-4 receptor, may serve as a diagnostic or disease-evolving tool for OA.

Wharton's Jelly Mesenchymal Stem Cells: Shaping the Future of Osteoarthritis Therapy with Advancements in Chitosan-Hyaluronic Acid Scaffolds

This review explores the potential of Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) in cartilage regeneration and osteoarthritis treatment. It covers key factors influencing chondrogenesis, including growth factors, cytokines, and hypoxia, focusing on precise timing. The effectiveness of three-dimensional cultures and scaffold-based strategies in chondrogenic differentiation is discussed. Specific biomaterials such as chitosan and hyaluronic acid are highlighted for tissue engineering. The document reviews clinical applications, incorporating evidence from animal research and early trials and molecular and histological assessments of chondrogenic differentiation processes. It addresses challenges and strategies for optimizing MSC-derived chondrocyte therapy, emphasizing the immunomodulatory properties of these cells. The review concludes as a comprehensive road map for future research and clinical applications in regenerative medicine.

Role of Plant Materials with Anti-inflammatory Effects in Phytotherapy of Osteoarthritis

Osteoarthritis (OA) is a common chronic articular degenerative disease characterized by articular cartilage degradation, synovial inflammation/immunity, and subchondral bone lesions. Recently, increasing interest has been devoted to treating or preventing OA with herbal medicines. The mechanism of action of plant raw materials used in osteoarthrosis treatment is well documented. They are sought after because of the high frequency of inflammation of the knee joint among both elderly and young people engaged in sports in which their knee joints are often exposed to high-stress conditions. The purpose of this work was to present some most effective and safe plant medicines with proven mechanisms of action that can help to alleviate the growing social problem of osteoarthrosis caused in recent years. A review of the available literature based primarily on the latest editions of ESCOP and EMA monographs and the latest scientific papers has made it possible to select and propose medical management of osteoarthrosis by ranking plant medicines according to their effectiveness. Clinical studies of raw plant materials, such as Harpagophyti radix, Olibanum indicum, and Urticae foliumet herba have indicated that these drugs should be considered the first choice in osteoarthrosis treatment. The efficacy of Rosae pseudo-fructus, Salicis cortex, Filipendulae ulmariae flos et herba, Ribis nigri folium, and externally applied Capsici fructus and Symphyti radix, has also been proven by pharmacological studies. All the plant medicines mentioned in the paper have been studied in detail in terms of their phytochemistry, which can help doctors in their decisionmaking in the treatment of osteoarthrosis.

CSF1-R inhibition attenuates posttraumatic osteoarthritis and quadriceps atrophy following ligament injury

Knee osteoarthritis contributes substantially to worldwide disability. Post-traumatic osteoarthritis (PTOA) develops secondary to joint injury, such as ligament rupture, and there is increasing evidence suggesting a key role for inflammation in the aetiology of PTOA and associated functional deficits. Colony stimulating factor 1 receptor (CSF1-R) has been implicated in the pathogenesis of musculoskeletal degeneration following anterior cruciate ligament (ACL) injury. We sought to assess the efficacy of CSF1-R inhibition to mitigate muscle and joint pathology in a mouse model of PTOA. Four-month-old mice were randomized to receive a CSF1-R inhibitor and studied for 7 or 28 days after joint injury. Additionally, we profiled synovial fluid samples for CSF1-R from patients with injury to their ACL. Transcriptomic analysis of quadriceps muscle and articular cartilage in CSF1-R inhibitor-treated animals at 7 days after injury revealed elevated chondrocyte differentiation within articular cartilage and enhanced metabolic and contractile gene expression within skeletal muscle. At 28 days post-injury, CSF1-R inhibition attenuated PTOA severity and mitigated skeletal muscle atrophy. Patient synovial fluid CSF1-R levels correlated with matrix metalloproteinase 13, a prognostic marker and molecular effector of PTOA. Our findings support an opportunity for CSF1-R targeting to mitigate the severity of PTOA and muscle atrophy after joint injury. KEY POINTS: Posttraumatic osteoarthritis (PTOA) of the knee commonly results from direct injury to the joint, which is characterized by pain, weakness, and disability. Induction of colony stimulating factor one receptor (CSF1-R) is positively associated with knee trauma severity, and the initial acute inflammatory state suppresses muscle recovery and degrades articular cartilage. Skeletal muscle and articular cartilage transcriptomic response following direct joint injury in a murine model of PTOA is rescued by pharmacological inhibition of CSF1-R. CSF1-R inhibition mitigated skeletal muscle atrophy and attenuated PTOA severity and synovitis. Patient synovial fluid CSF1-R levels correlated with matrix metalloproteinase 13, a prognostic marker and molecular effector of PTOA, offering further evidence for CSF1-R as a therapeutic target across musculoskeletal tissues after injury.

Celecoxib Combined with Tocilizumab Has Anti-Inflammatory Effects and Promotes the Recovery of Damaged Cartilage via the Nrf2/HO-1 Pathway In Vitro

Inflammation and oxidative stress are crucial for osteoarthritis (OA) pathogenesis. Despite the potential of pharmacological pretreatment of chondrocytes in preventing OA, its efficacy in preventing the progression of cartilage damage and promoting its recovery has not been examined. In this study, an H2O2-induced human OA-like chondrocyte cell model was created using H1467 primary human chondrocytes to evaluate the efficacy of interleukin (IL)-6 and cyclooxygenase (COX)-2 inhibitors (tocilizumab and celecoxib, respectively) in the prevention and treatment of cartilage damage. H2O2 significantly elevated the IL-6, COX-2, and matrix metalloproteinase (MMP)-13 levels. Although monotherapy decreased the levels, nuclear shrinkage and altered cell morphology, similar to those in the H2O2 group, were observed. The expression of these factors was significantly lower in the combination therapy group, and the cell morphology was maintained. Moreover, the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway was activated, and levels of the antioxidant protein heme oxygenase-1 (HO-1) were increased, especially in the combination group, indicating an anti-inflammatory effect. The treatment groups, particularly the combination group, demonstrated increased cell viability. Overall, the drug combination exhibited superior efficacy in preventing the progression of cartilage damage and promoted its recovery compared with the monotherapy. Given that the drugs herein are already in clinical use, they are suitable candidates for OA treatment.

Cellular and molecular mechanisms underlying obesity in degenerative spine and joint diseases

Degenerative spine and joint diseases, including intervertebral disc degeneration (IDD), ossification of the spinal ligaments (OSL), and osteoarthritis (OA), are common musculoskeletal diseases that cause pain or disability to the patients. However, the pathogenesis of these musculoskeletal disorders is complex and has not been elucidated clearly to date. As a matter of fact, the spine and joints are not independent of other organs and tissues. Recently, accumulating evidence demonstrates the association between obesity and degenerative musculoskeletal diseases. Obesity is a common metabolic disease characterized by excessive adipose tissue or abnormal adipose distribution in the body. Excessive mechanical stress is regarded as a critical risk factor for obesity-related pathology. Additionally, obesity-related factors, mainly including lipid metabolism disorder, dysregulated pro-inflammatory adipokines and cytokines, are reported as plausible links between obesity and various human diseases. Importantly, these obesity-related factors are deeply involved in the regulation of cell phenotypes and cell fates, extracellular matrix (ECM) metabolism, and inflammation in the pathophysiological processes of degenerative spine and joint diseases. In this study, we systematically discuss the potential cellular and molecular mechanisms underlying obesity in these degenerative musculoskeletal diseases, and hope to provide novel insights for developing targeted therapeutic strategies.

The roles of regulatory-compliant media and inflammatory/oxytocin priming selection in enhancing human mesenchymal stem/stromal cell immunomodulatory properties

Osteoarthritis (OA) represents a significant global health burden without a known disease modifying agent thereby necessitating pursuit of innovative therapeutic approaches. The infrapatellar fat pad (IFP) serves as a reservoir of mesenchymal stem/stromal cells (MSC), and with adjacent synovium plays key roles in joint disease affecting local inflammatory responses. Therapeutically, IFP-MSC have garnered attention for their potential in OA treatment due to their immunomodulatory and regenerative properties. However, optimizing their therapeutic efficacy necessitates a comprehensive understanding of how growth medium and inflammatory/hormonal priming influence their behavior. In this study, we isolated and expanded IFP-MSC in three different growth media: DMEM + 10% fetal bovine serum (FBS), DMEM + 10% human platelet lysate (HPL), and xeno-/serum-free synthetic (XFSF) medium. Subsequently, cells were induced with an inflammatory/fibrotic cocktail (TIC) with or without oxytocin (OXT). We evaluated various parameters including growth kinetics, phenotype, immunomodulatory capacity, gene expression, and macrophage polarization capacity. Our results revealed significant differences in the behavior of MSC cultured in different media. IFP-MSC cultured in HPL and XFSF exhibited superior growth kinetics and colony-forming abilities compared to those cultured in FBS. Furthermore, both HPL and XFSF media enhanced the expression of MSC markers (> 90%) and potentiated their immunomodulatory properties. Notably, XFSF-conditioned IFP-MSC demonstrated the highest attenuation of peripheral blood mononuclear cell (PBMC) proliferation, indicating their robust immunosuppressive capacity. Additionally, TIC priming further augmented the immunomodulatory functionality of MSC, with IFP-MSC exhibiting enhanced suppression of PBMC proliferation upon TIC priming. Of particular interest, gene expression analysis revealed distinct patterns in TIC + OXT induced MSC compared to TIC only induced, with upregulation of genes associated with immunomodulatory and regenerative functions. Furthermore, TIC + OXT priming promoted M2 polarization in macrophages, suggesting a potential therapeutic strategy for immune-mediated inflammatory joint conditions including OA. Our findings highlight the critical influence of growth medium and inflammatory/hormonal priming on MSC behavior and therapeutic potential. XFSF and HPL media offer promising alternatives to FBS, enhancing MSC growth and immunomodulatory properties. Moreover, TIC + OXT priming represents a novel approach to augment MSC immunomodulation and promote M2 polarization, providing insights into potential therapeutic strategies for OA and other immune-mediated inflammatory conditions.

Proinflammatory Cytokines Enhance the Mineralization, Proliferation, and Metabolic Activity of Primary Human Osteoblast-like Cells

Osteoporosis is a progressive metabolic bone disease characterized by decreased bone density and microarchitectural deterioration, leading to an increased risk of fracture, particularly in postmenopausal women and the elderly. Increasing evidence suggests that inflammatory processes play a key role in the pathogenesis of osteoporosis and are strongly associated with the activation of osteoclasts, the cells responsible for bone resorption. In the present study, we investigated, for the first time, the influence of proinflammatory cytokines on the osteogenic differentiation, proliferation, and metabolic activity of primary human osteoblast-like cells (OBs) derived from the femoral heads of elderly patients. We found that all the proinflammatory cytokines, IL-1β, TNF-α, IL-6, and IL-8, enhanced the extracellular matrix mineralization of OBs under differentiation-induced cell culture conditions. In the cases of IL-1β and TNF-α, increased mineralization was correlated with increased osteoblast proliferation. Additionally, IL-1β- and TNF-α-increased osteogenesis was accompanied by a rise in energy metabolism due to improved glycolysis or mitochondrial respiration. In conclusion, we show here, for the first time, that, in contrast to findings obtained with cell lines, mesenchymal stem cells, or animal models, human OBs obtained from patients exhibited significantly enhanced osteogenesis upon exposure to proinflammatory cytokines, probably in part via a mechanism involving enhanced cellular energy metabolism. This study significantly contributes to the field of osteoimmunology by examining a clinically relevant cell model that can help to develop treatments for inflammation-related metabolic bone diseases.

Intramuscular methylprednisolone in hand osteoarthritis: a retrospective cohort study

Objectives

To explore patient characteristics associated with response to intramuscular methylprednisolone (MP) therapy in hand OA.

Methods

We performed an exploratory monocentric retrospective study. Patients with a clinical diagnosis of hand OA who visited our outpatient clinic between July 2016 and June 2021 and received at least once an intramuscular MP injection were included. Clinical data, including laboratory and radiologic results, were retrieved from electronic patient records (EPRs). Patients' reported response to MP and its duration in the first 6 months after injection was based on free text from the EPRs. Response was categorized into three groups: no response or worsening of symptoms, modest response and good response. Duration of response was categorized as short-term (<2 weeks) or long-term (≥2 weeks). Multivariable logistic regression models were performed to determine factors associated with good response to therapy with MP.

Results

Data from 262 hand OA patients (76% female) were analysed. A good response was experienced by 150 patients (57.2%). Among those with modest-good response, the perceived response of 162 patients (80.6%) lasted ≥2 weeks. Univariate regression analysis indicated that the level of CRP was associated with good response [odds ratio 1.08 (95% CI 1.00, 1.17)]. However, multivariate regression analysis showed no statistically significant associations.

Conclusion

In this retrospective study, more than half of hand OA patients displayed good response to intramuscular MP administration. The possible relation between the presence of low-grade inflammation and the response to this therapy warrants further investigation.

Musculoskeletal Failure

Osteoarthritis, osteoporosis, and sarcopenia are prevalent musculoskeletal disorders that significantly impact the aging population's health and quality of life. Osteoarthritis, characterized by joint inflammation, leads to pain, stiffness, and reduced mobility. Osteoporosis, a condition marked by bone density loss, increases fracture susceptibility, especially in postmenopausal women and older adults. Sarcopenia, the age-related loss of muscle mass and function, contributes to frailty and an increased risk of falls. Combined, osteoarthritis, osteoporosis and sarcopenia constitute "Musculoskeletal Failure." These 3 conditions share common risk factors like aging, genetics, and hormonal changes, as well as unhealthy lifestyle behaviors resulting in systemic chronic inflammation. Healthy lifestyle behaviors, including regular physical activity and a nutritious diet across the lifespan play a crucial role in the prevention and management of musculoskeletal failure. Awareness of the relationship between lifestyle behaviors, systemic chronic inflammation and the development and progression of these 3 common conditions is a key step in prevention, early detection and are essential for addressing the complex interplay of these musculoskeletal disorders. As the global population ages, understanding and effectively preventing and managing osteoarthritis, osteoporosis, and sarcopenia become paramount for promoting healthy aging and mitigating the societal and economic burden associated with these conditions.

Label-free long-term measurements of adipocyte differentiation from patient-driven fibroblasts and quantitative analyses of in situ lipid droplet generation

The visualization and tracking of adipocytes and their lipid droplets (LDs) during differentiation are pivotal in developmental biology and regenerative medicine studies. Traditional staining or labeling methods, however, pose significant challenges due to their labor-intensive sample preparation, potential disruption of intrinsic cellular physiology, and limited observation timeframe. This study introduces a novel method for long-term visualization and quantification of biophysical parameters of LDs in unlabeled adipocytes, utilizing the refractive index (RI) distributions of LDs and cells. We employ low-coherence holotomography (HT) to systematically investigate and quantitatively analyze the 42-day redifferentiation process of fat cells into adipocytes. This technique yields three-dimensional, high-resolution refractive tomograms of adipocytes, enabling precise segmentation of LDs based on their elevated RI values. Subsequent automated analysis quantifies the mean concentration, volume, projected area, and dry mass of individual LDs, revealing a gradual increase corresponding with adipocyte maturation. Our findings demonstrate that HT is a potent tool for non-invasively monitoring live adipocyte differentiation and analyzing LD accumulation. This study, therefore, offers valuable insights into adipogenesis and lipid research, establishing HT and image-based analysis as a promising approach in these fields.

Amentoflavone alleviated cartilage injury and inflammatory response of knee osteoarthritis through PTGS2

The role of amentoflavone on cartilage injury in knee osteoarthritis (KOA) rats and the underlying mechanism were explored. KOA rat and IL-1β-stimulated chondrocyte models were constructed. MTT, colony formation, and ELISA were performed to determine the cytotoxicity, cell proliferation, and inflammatory factors. The role of PTGS2 in IL-1β-stimulated chondrocytes was also confirmed through transfecting PTGS2 overexpression and silencing plasmids. Further, we analyzed how amentoflavone regulated PTGS2 to improve IL-1β-stimulated chondrocytes in vitro. Additionally, we analyzed the expression of PTGS2 after amentoflavone treatment. In vivo, HE and Safranin-O staining were carried out, and the inflammatory response was detected by ELISA and HE staining. In addition, we also analyzed the regulatory effect of amentoflavone on PTGS2 and explored the mechanism effect of PTGS2 in vitro and in vivo. The results indicated that PTGS2 was the downstream molecule of amentoflavone, which was highly expressed in IL-1β-stimulated chondrocytes and KOA rats, and amentoflavone decreased PTGS2 expression. We also confirmed the potential role of amentoflavone on KOA, which was also characterized by the repair of cartilage injury, reduction of inflammatory infiltration, and improvement of functional disability. Consistent with in vivo results, in vitro experiments gave the same conclusions. Amentoflavone reduced PTGS2 expression in IL-1β-stimulated chondrocytes and inhibited inflammation of chondrocytes via PTGS2. Collectively, the results confirmed that this drug was the potential targeted drug for KOA, whose repair effect on cartilage injury was partly related to PTGS2.

Corticosteroid injections for the treatment of osteoarthritis present a wide spectrum of effects ranging from detrimental to disease-modifying: A systematic review of preclinical evidence by the ESSKA Orthobiologic Initiative

PURPOSE

Aim of this systematic review of preclinical evidence was to determine the effects of intra-articular corticosteroid (CS) injections in joints affected by osteoarthritis (OA).

METHODS

A systematic review was performed on animal studies evaluating intra-articular CS injections for OA joints. The search was performed on PubMed, Cochrane, and Web of Science databases. A synthesis of the results was performed investigating CS effects by evaluating studies comparing CS with control groups. Morphological, histological, immunohistochemistry evaluations, clinical outcomes, biomarkers and imaging results were evaluated. The risk of bias was assessed according to the Systematic Review Centre for Laboratory Animal Experimentation's tool.

RESULTS

Thirty-two articles analysing CS effects in OA animal models were included (1079 joints), 18 studies on small and 14 on large animals. CS injections showed overall positive effects in at least one of the outcomes in 68% of the studies, while 16% reported a deleterious effect. CS improved cartilage and synovial outcomes in 68% and 60% of the studies, but detrimental effects were documented in 11% and 20% of the studies, respectively. Clinical parameters evaluated in terms of pain, lameness or joint swelling improved in 63% of the studies but deteriorated in 13%. Evidence is limited on imaging and biomarkers results, as well as on the best CS type, dose, formulation and injection protocol. The risk of bias assessment revealed a 28% low and an 18% high risk of bias.

CONCLUSION

Intra-articular CS injections induced a wide range of results on OA joints in experimental animal models, from disease-modifying and positive effects on pain and joint function at short-term evaluation to the lack of benefit or even negative effects. This underlines the need to identify more specific indications and treatment modalities to avoid possible detrimental effects while maximising the anti-inflammatory properties and the benefits of intra-articular CS in OA joints.

LEVEL OF EVIDENCE

Level II.

Analyzing the Role of Specific Damage-Associated Molecular Patterns-Related Genes in Osteoarthritis and Investigating the Association between β-Amyloid and Apolipoprotein E Isoforms

INTRODUCTION

Osteoarthritis (OA) is a prevalent chronic joint disorder. It is characterized by an immune response that maintains a low level of inflammation throughout its progression. During OA, cartilage degradation leads to the release of damage-associated molecular patterns (DAMPs), which intensify the inflammatory response. β-Amyloid is a well-recognized DAMP in OA, can interact with APOE isoforms.

METHODS

This study identified DAMPs-related genes in OA using bioinformatics techniques. Additionally, we examined the expression levels of β-amyloid and apolipoprotein E (ApoE) isoforms by enzyme-linked immunosorbent assay.

RESULTS

We identified 10 key genes by machine learning techniques. Immune infiltration analysis revealed upregulation of various immune cell types in OA cartilage, underscoring the critical role of inflammation in OA pathogenesis. In the validation study, elevated serum levels of β-amyloid in knee osteoarthritis (KOA) patients were confirmed, showing positive correlations with ApoE2 and ApoE4. Notably, ApoE3 was identified as an independent protective factor against KOA.

CONCLUSION

In this bioinformatics analysis, we identified the DAMPs-related genes of KOA and explored their potential functions and regulatory networks. The high expression of β-amyloid in KOA was confirmed by experiments, and the correlation between β-amyloid and ApoE2, ApoE4 in KOA was revealed for the first time, this provides a new way to explore the pathogenesis of KOA and to study the therapeutic targets of KOA.

The role of neutrophils in pain: systematic review and meta-analysis of animal studies

ABSTRACT

The peripheral inflammatory response is an attractive therapeutic target for pain treatment. Neutrophils are the first circulating inflammatory cells recruited to sites of injury, but their contribution to pain outcomes is unclear. We performed a systematic review and meta-analysis of original preclinical studies, which evaluated the effect of preemptive neutrophil depletion on pain outcomes (PROSPERO registration number: CRD42022364004). Literature search (PubMed, January 19, 2023) identified 49 articles, which were meta-analyzed using a random-effects model. The risk of bias was evaluated using SYRCLE's tool. The pooled effect considering all studies showed that neutrophil depletion induced a consistent pain reduction. Inflammatory, joint, neuropathic, and visceral pain showed significant pain alleviation by neutrophil depletion with medium-large effect sizes. However, muscle and postoperative pain were not significantly alleviated by neutrophil depletion. Further analysis showed a differential contribution of neutrophils to pain outcomes. Neutrophils had a higher impact on mechanical hyperalgesia, followed by nociceptive behaviors and mechanical allodynia, with a smaller contribution to thermal hyperalgesia. Interspecies (mice or rats) differences were not appreciated. Analyses regarding intervention unveiled a lower pain reduction for some commonly used methods for neutrophil depletion, such as injection of antineutrophil serum or an anti-Gr-1 antibody, than for other agents such as administration of an anti-Ly6G antibody, fucoidan, vinblastine, CXCR1/2 inhibitors, and etanercept. In conclusion, the contribution of neutrophils to pain depends on pain etiology (experimental model), pain outcome, and the neutrophil depletion strategy. Further research is needed to improve our understanding on the mechanisms of these differences.

Characterization of PANoptosis-related genes with immunoregulatory features in osteoarthritis

This study aimed to characterize PANoptosis-related genes with immunoregulatory features in osteoarthritis (OA) and investigate their potential diagnostic and therapeutic implications. Gene expression data from OA patients and healthy controls were obtained from the Gene Expression Omnibus (GEO) database. Differential expression analysis and functional enrichment analysis were conducted to identify PANoptosis-related genes (PRGs) associated with OA pathogenesis. A diagnostic model was developed using LASSO regression, and the diagnostic value of key PRGs was evaluated using Receiver Operating Characteristic Curve (ROC) analysis. The infiltration of immune cells and potential small molecule agents were also examined. A total of 39 differentially expressed PANoptosis-related genes (DE-PRGs) were identified, with functional enrichment analysis revealing their involvement in inflammatory response regulation and immune modulation pathways. Seven key PRGs, including CDKN1A, EZH2, MEG3, NR4A1, PIK3R2, S100A8, and SYVN1, were selected for diagnostic model construction, demonstrating high predictive performance in both training and validation datasets. The correlation between key PRGs and immune cell infiltration was explored. Additionally, molecular docking analysis identified APHA-compound-8 as a potential therapeutic agent targeting key PRGs. This study identified and analyzed PRGs in OA, uncovering their roles in immune regulation. Seven key PRGs were used to construct a diagnostic model with high predictive performance. The identified PRGs' correlation with immune cell infiltration was elucidated, and APHA-compound-8 was highlighted as a potential therapeutic agent. These findings offer novel diagnostic markers and therapeutic targets for OA, warranting further in vivo validation and exploration of clinical applications.

Short Link N Modulates Inflammasome Activity in Intervertebral Discs Through Interaction with CD14

Intervertebral disc degeneration and pain are associated with the nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing 3 (NLRP3) inflammasome activation and the processing of interleukin-1 beta (IL-1β). Activation of thehm inflammasome is triggered by Toll-like receptor stimulation and requires the cofactor receptor cluster of differentiation 14 (CD14). Short Link N (sLN), a peptide derived from link protein, has been shown to modulate inflammation and pain in discs in vitro and in vivo; however, the underlying mechanisms remain elusive. This study aims to assess whether sLN modulates IL-1β and inflammasome activity through interaction with CD14. Disc cells treated with lipopolysaccharides (LPS) with or without sLN were used to assess changes in Caspase-1, IL-1β, and phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB). Peptide docking of sLN to CD14 and immunoprecipitation were performed to determine their interaction. The results indicated that sLN inhibited LPS-induced NFκB and Caspase-1 activation, reducing IL-1β maturation and secretion in disc cells. A significant decrease in inflammasome markers was observed with sLN treatment. Immunoprecipitation studies revealed a direct interaction between sLN and the LPS-binding pocket of CD14. Our results suggest that sLN could be a potential therapeutic agent for discogenic pain by mitigating IL-1β and inflammasome activity within discs.

Lipidome profiling of neutrophil-derived extracellular vesicles unveils their contribution to the ensemble of synovial fluid-derived extracellular vesicles during joint inflammation

The molecular signature of cell-derived extracellular vesicles (EVs) from synovial fluid (SF) offers insights into the cells and molecular processes associated with joint disorders and can be exploited to define biomarkers. The EV-signature is determined by cargo molecules and the lesser-studied lipid bilayer. We here investigated the lipidome of SF-EVs in inflamed joints derived from Rheumatoid Arthritis (RA) and Spondyloarthritis (SpA) patients, two autoimmune-driven joint diseases, and compared these signatures to the lipid profile of equine SF-EVs obtained during induced acute synovitis. Since neutrophils are primary SF-infiltrating cells during these inflammatory joint diseases, we also analyzed how inflammatory stimuli alter the lipidomic profile of human and equine neutrophil-derived EVs (nEVs) in vitro and how these signatures relate to the lipidome signatures of SF-EVs from inflamed joints. We identified neutrophil stimulation intensity-dependent changes in the lipidomic profile of nEVs with elevated presence of dihexosylceramide (lactosylceramide), phosphatidylserine, and phosphatidylethanolamine ether-linked lipid classes in human nEVs upon full neutrophil activation. In horses, levels of monohexosylceramide (glucosylceramide) increased instead of dihexosylceramide, indicating species-specific differences. The lipid profiles of RA and SpA SF-EVs were relatively similar and showed a relative resemblance with stimulated human nEVs. Similarly, the lipidome of equine synovitis-derived SF-EVs closer resembled the one of stimulated equine nEVs. Hence, lipidome profiling can provide insights into the contribution of nEVs to the heterogeneous pool of SF-EVs, deepening our understanding of inflammatory joint diseases and revealing molecular changes in joint homeostasis, which can lead to the development of more precise disease diagnosis and treatment strategies.

Optimizing long-term joint health in the treatment of hemophilia

INTRODUCTION

The improved quality of care and increased drug availability have shifted the goal of treating people with hemophilia from life-threatening bleeding prevention to joint health preservation and quality of life amelioration. Many tools are now available to the clinician in order to optimize the management of hemophilic arthropathy.

AREAS COVERED

This paper reviews the pivotal role of ultrasound evaluation in early detection of joint bleeding and differential diagnosis of joint pain, with a focus on the feasibility of a long-term monitoring of joint health through the use of artificial intelligence and telemedicine. The literature search methodology included using keywords to search in PubMed and Google Scholar, and articles used were screened by the coauthors of this review.

EXPERT OPINION

Joint ultrasound is a practical point-of-care tool with many advantages, including immediate correlation between imaging and clinical presentation, and dynamic evaluation of multiple joints. The potential of telemedicine care, coupled with a point-of-care detection device assisted by artificial intelligence, holds promises for even earlier diagnosis and treatment of joint bleeding. A multidisciplinary approach including early intervention by physical medicine and rehabilitation (PMR) physicians and physiotherapists is crucial to ensure the best possible quality of life for the patient.