Osteoarthritis: Pathology, Diagnosis, and Treatment Options

Expanding the ABCC-tool for osteoarthritis: Development and content validation

Objective

Osteoarthritis (OA) care should be more person-centered based on physical, emotional and social aspects, instead of the current stepped-care approach solely based on physical symptoms, according to OA patients. By developing a novel module for OA in the Assessment of Burden of Chronic Condition (ABCC)-tool, a tool based on these three aspects, experienced quality of OA care and shared-decision making are expected to improve.

Design

The development of the novel OA module involved a triangular iterative process, interviewing OA patients and healthcare professionals in the field of OA, an expert panel and a literature search to identify the needs to improve OA care. Patients provided feedback on the first version of the OA module, leading to a second version. This second version was used to evaluate content validity. OA patients and healthcare professionals in the field of OA were asked to evaluate relevance, comprehensiveness and comprehensibility, based on the COSMIN methodology. For healthcare professionals, the item-content validity index (I-CVI) was calculated.

Results

The module includes questions about pain, kinesiophobia and joint stiffness. For all three questions, 94% of the patients found these questions important for patients with OA. The I-CVI scores of the healthcare professionals ranged from 1.0 (pain, kinesiophobia) to 0.75 (joint stiffness).

Conclusion

A novel, condition-specific OA module is developed for the ABCC-tool, as a supplement to the generic questions. The module includes three questions, to measure OA specific complaints. This novel module is intended to make the ABCC-tool more elaborate and useable for a larger population.

Proteomic and lipidomic landscape of the infrapatellar fat pad and its clinical significance in knee osteoarthritis

Osteoarthritis (OA) is a prevalent joint disease that can be exacerbated by lipid metabolism disorders. The intra-articular fat pad (IFP) has emerged as an active participant in the pathological changes of knee OA (KOA). However, the proteomic and lipidomic differences between IFP tissues from KOA and control individuals remain unclear. Samples of IFP were collected from individuals with and without OA (n = 6, n = 6). Subsequently, these samples underwent liquid chromatography/mass spectrometry-based label-free quantitative proteomic and lipidomic analysis to identify differentially expressed proteins (DEPs) and lipid metabolites (DELMs). The DEPs were further subjected to enrichment analysis, and hub DEPs were identified using multiple algorithms. Additionally, an OA diagnostic model was constructed based on the identified hub DEPs or DELMs. Furthermore, CIBERSORT was utilized to investigate the correlation between hub protein expression and immune-related modules in IFP of OA. Our results revealed the presence of 315 DEPs and eight DELMs in IFP of OA patients compared to the control group. Enrichment analysis of DEPs highlighted potential alterations in pathways related to coagulation, complement, fatty acid metabolism, and adipogenesis. The diagnostic model incorporating four hub DEPs (AUC = 0.861) or eight DELMs (AUC = 0.917) exhibited excellent clinical validity for diagnosing OA. Furthermore, the hub DEPs were found to be associated with immune dysfunction in IFP of OA. This study presents a distinct proteomic and lipidomic landscape of IFP between individuals with OA and those without. These findings provide valuable insights into the molecular changes associated with potential mechanisms underlying OA.

Intra-articular injection of stigmasterol-loaded nanoparticles reduce pain and inhibit the inflammation and joint destruction in osteoarthritis rat model: A pilot study

Stigmasterol, a plant-derived sterol, sharing structural similarity with cholesterol, has demonstrated anti-osteoarthritis (OA) properties, attributed to its antioxidant and anti-inflammatory capabilities. Given that OA often arises in weight bearing or overused joints, prolonged localized treatment effectively targets inflammatory aspects of the disease. This research explored the impact of stigmasterol-loaded nanoparticles delivered via intra-articular injections in an OA rat model. Employing mesoporous silica nanomaterials (MSNs) combined with β-cyclodextrin (β-CD) as a vehicle, stigmasterol was loaded in conjunction with tannic acid, forming stigmasterol/β-CD-MSNs to facilitate a sustained stigmasterol release. The study employed RAW 264.7 cells to examine the in vitro cytotoxicity and anti-inflammatory effect of stigmasterol/β-CD-MSNs. For in vivo experimentation, we used healthy control rats and monosodium iodoacetate (MIA)-induced OA rats, separated into five groups, varying the injection substances. In vitro findings indicated that stigmasterol/β-CD-MSNs suppressed the mRNA expression of key pro-inflammatory mediators such as interleukin-6, tumor necrosis factor-α, and matrix metalloproteinase-3 in a dose-dependent manner. In vivo experiments revealed a substantial decrease in the mRNA levels of pro-inflammatory factors in the stigmasterol(50 µg)/β-CD-MSN group compared to the others. Macroscopic, radiographic, and histological evaluations established that intra-articular injections of stigmasterol/β-CD-MSNs inhibited cartilage degeneration and subchondral bone deterioration. Therefore, in a chemically induced OA rat model, intra-articular stigmasterol delivery was associated with reduction in both local and systemic inflammatory responses, alongside a slowdown in joint degradation and arthritic progression.

Circulating cytokines levels and osteoarthritis: A Mendelian randomization study

BACKGROUND

Previous traditional observational studies have suggested the contribution of several cytokines and growth factors to the development of osteoarthritis (OA). This study aimed to determine the association of circulating cytokine and growth factor levels with OA.

METHODS

We used two-sample Mendelian randomization (MR) to explore the causality between circulating cytokine and growth factor levels and OA [including knee or hip OA (K/HOA), knee OA (KOA), and hip OA (HOA)]. Summary level data for circulating cytokine and growth factor levels were sourced from a genome-wide association study (GWAS) involving 8,293 participants of Finnish ancestry. Single-nucleotide polymorphisms related to K/HOA (39,427 cases and 378,169 controls), KOA (24,955 cases and 378,169 controls), and HOA (15,704 cases and 378,169 controls) were obtained from a previous GWAS. The inverse variance weighted (IVW) method was primarily used for our MR analysis. For exposures to only one relevant SNP as IV, we used the Wald ratio as the major method to assess causal effects. We also conducted a series of sensitivity analyses to improve the robustness of the results.

RESULTS

Circulating vascular endothelial growth factor levels were suggestively associated with an increased risk of K/HOA (odds ratio (OR) = 1.034; 95 % confidence interval (CI) = 1.013-1.055; P = 0.001), KOA (OR = 1.034; 95 % CI = 1.014-1.065; P = 0.002), and HOA (OR = 1.039; 95 % CI = 1.003-1.067; P = 0.034). Circulating interleukin (IL)-12p70 levels was suggestively associated with K/HOA (OR = 1.047; 95 % CI = 1.018-1.077; P = 0.001), KOA (OR = 1.058; 95 % CI = 1.022-1.095; P = 0.001), and HOA (OR = 1.044; 95 % CI = 1.000-1.091; P = 0.048). Circulating IL-18 levels were suggestively associated with HOA (OR = 1.068; 95 % CI = 1.014-1.125; P = 0.012). However, limited evidence exists to support causal genetic relationships between other circulating cytokines, growth factor levels and K/HOA, KOA, and HOA.

CONCLUSIONS

Our MR analysis provides suggestive evidence of causal relationships between circulating cytokines and growth factors levels and OA, providing new insights into the etiology of OA.

Activation of kappa opioid receptor suppresses post-traumatic osteoarthritis via sequestering STAT3 on the plasma membrane

OBJECTIVE

Kappa opioid receptor (KOR) signaling is involved in joint development and inflammation in Osteoarthritis (OA), while the biochemical mechanism remains unclarified. This study aims to investigate downstream molecular events of KOR activation, to provide novel perspectives in OA pathology.

METHODS

U50,488H, a selective KOR agonist, was intra-articularly injected in mice upon destabilization of the medial meniscus (DMM) as OA models, with PBS injection as control. The behavioral and histological evaluation was assessed by hot plate test and red solid green staining, respectively. Alterations in mRNA and protein expression were assessed by RNA-seq, RT-qPCR, immunohistochemistry and western blotting (WB) in chondrocytes treated with TNF-α or TNF-α + U50,488H. Proteins interacted with KOR were explored using proximity labeling followed by mass spectrometry and then testified by co-immunoprecipitation (Co-IP) assay and immunofluorescence (IF).

RESULTS

OA-induced pain was reduced and cartilage degeneration was alleviated upon KOR activation in DMM mice. In chondrocytes, activation of KOR reversed the upregulation of MMPs, IL-6, IL-1β and phosphorylated(p-) STAT3, stimulated by TNF-α, while the expression of NF-κB, MAPKs and AKT signaling weren't reversed. RNA-seq and IF results presented that KOR activation evidently reduced STAT3 nuclear translocation in chondrocytes upon TNF-α stimuli. The reduction may be resulted from the binding of KOR and STAT3 in the plasma membrane, revealed by proximity labeling and Co-IP results.

CONCLUSIONS

KOR activation protects cartilage from OA, and this protective effect is mainly exerted via sequestering STAT3 on the plasma membrane, resulting in inactivation of STAT3-dependent immune responses which otherwise contributes to OA.

Polygonatum sibiricum polysaccharides protect against knee osteoarthritis by inhibiting the TLR2/NF-κB signaling pathway in vivo and in vitro

Polygonatum sibiricum polysaccharides (PSP), the primary constituent of Polygonatum sibiricum, have been shown to exhibit a wide range of pharmacological effects, but their impact on osteoarthritis (OA) remains unclear. The objective of this study was to investigate the protective effects of PSP against OA and to elucidate its underlying molecular mechanism. In our in vitro experiments, PSP not only inhibited the IL-1β-induced inflammatory responses and the nuclear factor kappa-B (NF-κB) signaling pathway in chondrocytes but also regulated the cartilage matrix metabolism. In addition, we detected 394 significantly differentially expressed genes through RNA-seq analysis on PSP-intervened chondrocytes, and the toll-like receptor 2 (TLR2) was identified as the most important feature by functional network analysis and qRT-PCR. It was also revealed that PSP treatment significantly reversed the IL-1-induced up-regulation of TLR2 expression in chondrocytes, while TLR2 overexpression partially inhibited the regulatory effects of PSP on inflammation, NF-κB signaling pathway and matrix metabolism. In our in vivo experiments, PSP treatment alleviated the development of destabilization of medial meniscus (DMM)-induced OA in mouse knee joints, inhibited the DMM-induced activation of the TLR2/NF-κB signaling pathway in mouse knee joint cartilage, and reduced the serum levels of inflammatory cytokines. In conclusion, PSP exerts its anti-inflammatory, matrix synthesis-promoting and matrix catabolism-suppressing effects in knee OA by inhibiting the TLR2/NF-κB signaling pathway, suggesting that PSP may be potentially targeted as a novel all-natural, low-toxicity drug for OA prevention and treatment.

CKIP-1-Loaded Cartilage-Affinitive Nanoliposomes Reverse Osteoarthritis by Restoring Chondrocyte Homeostasis

Osteoarthritis (OA) is a chronic joint disease characterized by cartilage imbalance and disruption of cartilage extracellular matrix secretion. Identifying key genes that regulate cartilage differentiation and developing effective therapeutic strategies to restore their expression is crucial. In a previous study, we observed a significant correlation between the expression of the gene encoding casein kinase-2 interacting protein-1 (CKIP-1) in the cartilage of OA patients and OA severity scores, suggesting its potential involvement in OA development. To test this hypothesis, we synthesized a chondrocyte affinity plasmid, liposomes CKIP-1, to enhance CKIP-1 expression in chondrocytes. Our results demonstrated that injection of CAP-Lipos-CKIP-1 plasmid significantly improved OA joint destruction and restored joint motor function by enhancing cartilage extracellular matrix (ECM) secretion. Histological and cytological analyses confirmed that CKIP-1 maintains altered the phosphorylation of the signal transduction molecule SMAD2/3 of the transforming growth factor-β (TGF-β) pathway by promoting the phosphorylation of the 8T, 416S sit. Taken together, this work highlights a novel approach for the precise modulation of chondrocyte phenotype from an inflammatory to a noninflammatory state for the treatment of OA and may be broadly applicable to patients suffering from other arthritic diseases.

Functionalized hydrogels as smart gene delivery systems to treat musculoskeletal disorders

Despite critical advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy based on the delivery of therapeutic genetic sequences has strong value to offer effective, durable options to decisively manage such disorders. Furthermore, scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy, allowing for the spatiotemporal delivery of candidate genes to sites of injury. Among the many scaffolds for musculoskeletal research, hydrogels raised increasing attention in addition to other potent systems (solid, hybrid scaffolds) due to their versatility and competence as drug and cell carriers in tissue engineering and wound dressing. Attractive functionalities of hydrogels for musculoskeletal therapy include their injectability, stimuli-responsiveness, self-healing, and nanocomposition that may further allow to upgrade of them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. Such functionalized hydrogels may also be tuned to successfully transfer therapeutic genes in a minimally invasive manner in order to protect their cargos and allow for their long-term effects. In light of such features, this review focuses on functionalized hydrogels and demonstrates their competence for the treatment of musculoskeletal disorders using gene therapy procedures, from gene therapy principles to hydrogel functionalization methods and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are being discussed in the perspective of translation in patients. STATEMENT OF SIGNIFICANCE: Despite advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy has strong value in offering effective, durable options to decisively manage such disorders. Scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy. Among many scaffolds for musculoskeletal research, hydrogels raised increasing attention. Functionalities including injectability, stimuli-responsiveness, and self-healing, tune them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. This review introduces functionalized hydrogels for musculoskeletal disorder treatment using gene therapy procedures, from gene therapy principles to functionalized hydrogels and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are discussed from the perspective of translation in patients.

α-Ketoglutarate alleviates osteoarthritis by inhibiting ferroptosis via the ETV4/SLC7A11/GPX4 signaling pathway

Osteoarthritis (OA) is the most common degenerative joint disorder that causes disability in aged individuals, caused by functional and structural alterations of the knee joint. To investigate whether metabolic drivers might be harnessed to promote cartilage repair, a liquid chromatography-mass spectrometry (LC-MS) untargeted metabolomics approach was carried out to screen serum biomarkers in osteoarthritic rats. Based on the correlation analyses, α-ketoglutarate (α-KG) has been demonstrated to have antioxidant and anti-inflammatory properties in various diseases. These properties make α-KG a prime candidate for further investigation of OA. Experimental results indicate that α-KG significantly inhibited H2O2-induced cartilage cell matrix degradation and apoptosis, reduced levels of reactive oxygen species (ROS) and malondialdehyde (MDA), increased superoxide dismutase (SOD) and glutathione (GSH)/glutathione disulfide (GSSG) levels, and upregulated the expression of ETV4, SLC7A11 and GPX4. Further mechanistic studies observed that α-KG, like Ferrostatin-1 (Fer-1), effectively alleviated Erastin-induced apoptosis and ECM degradation. α-KG and Fer-1 upregulated ETV4, SLC7A11, and GPX4 at the mRNA and protein levels, decreased ferrous ion (Fe2+) accumulation, and preserved mitochondrial membrane potential (MMP) in ATDC5 cells. In vivo, α-KG treatment inhibited ferroptosis in OA rats by activating the ETV4/SLC7A11/GPX4 pathway. Thus, these findings indicate that α-KG inhibits ferroptosis via the ETV4/SLC7A11/GPX4 signaling pathway, thereby alleviating OA. These observations suggest that α-KG exhibits potential therapeutic properties for the treatment and prevention of OA, thereby having potential clinical applications in the future.

Is there a role for autologous conditioned serum injections in osteoarthritis? A systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To assess whether patient reported outcome measures (PROMs) improve after autologous conditioned serum (ACS) administration in patients with osteoarthritis.

METHODS

Databases and clinical trial registers were searched to March 2024 for randomised controlled trial (RCTs) comparing ACS vs comparators/controls. Primary outcomes were pain, function and stiffness measured with Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and visual analogue scale (VAS). Secondary outcome was complications. Risk of bias (RoB) and certainty of evidence were assessed using RoB 2 and GRADE respectively. Meta-analysis was undertaken using RevMan v5.4. Results are presented as standardised mean differences (SMD) or mean differences (MD) with 95% confidence intervals (CI). Sensitivity analysis compared all comparators and saline control.

RESULTS

Five RCTs were identified (n = 741 participants); two (n = 529 participants) compared ACS against saline (placebo). Three studies were "some concern" and two studies "high risk" for bias. Analysis comparing ACS with all comparators significantly favoured ACS at 6 months for WOMAC: SMD -0.61 (95% CI -1.01 to -0.21; p = 0.003); and VAS: SMD -1.24 (95% CI -2.11 to -0.38; p = 0.005); with high heterogeneity. Comparing ACS with saline, there was no significant difference in WOMAC or VAS at 6 months: SMD -0.40 (95% CI -0.93 to 0.12; p = 0.13) and MD -9.87 (95% CI -27.73 to 7.98, p = 0.28). Complications were similar: ACS (24.8%) vs saline (24.4%), with serious complications rare.

CONCLUSION

There is currently insufficient data to support the use of ACS in osteoarthritis with conflicting results when compared to alternative therapies and saline control, with high heterogeneity. Before consideration as a potential treatment, a high-quality multicentre RCT is required to assess the efficacy of ACS.

A Novel Dinuclear Complex-PLC Composite Material as Fluorescent Switch in Treatment on Osteoarthritis

In this study, we synthesized a novel Co(II)-containing coordination compound (CP) [Co2(MMBA)2(HPT)2(H2O)2]·2H2O (1) through a solvothermal reaction of Co(NO3)6·6H2O with 3-(pyridin-2-yl)-1 H-1,2,4-triazole (HPT) and 2-(4-methylbenzoyl)benzoic acid (HMMBA). Fluorescence spectroscopy confirmed that this compound exhibited superior blue fluorescence properties compared to the original ligands. Further, aspirin (ASA) was loaded onto this CP via physical adsorption to create CP-ASA. Interestingly, the fluorescence properties of the CP decreased with the loading of the drug but were restored upon drug release. Leveraging the unique optical properties and biocompatibility of Polymer Liquid Crystal (PLC), we further encapsulated CP-ASA, forming the CP-PLC@ASA composite. The target product was confirmed through various characterization techniques including Elemental Analysis (EA), Fourier-Transform Infrared Spectroscopy (FT-IR), Powder X-Ray Diffraction (PXRD), and Thermogravimetric Analysis (TGA). Moreover, the biological activity of this composite was evaluated in vitro for osteoarthritis, and its potential mechanisms were explored.

Identification and Construction of a Disulfidptosis-Mediated Diagnostic Model and Associated Immune Microenvironment of Osteoarthritis from the Perspective of PPPM

Background

Osteoarthritis (OA) is a major cause of human disability. Despite receiving treatment, patients with the middle and late stage of OA have poor survival outcomes. Therefore, within the framework of predictive, preventive, and personalized medicine (PPPM/3PM), early personalized diagnosis of OA is particularly prominent. PPPM aims to accurately identify disease by integrating multiple omic techniques; however, the efficiency of currently available methods and biomarkers in predicting and diagnosing OA should be improved. Disulfidptosis, a novel programmed cell death mechanism and appeared in particular metabolic status, plays a mysterious characteristic in the occurrence and development of OA, which warrants further investigation.

Methods

In this study, we integrated three public datasets from the Gene Expression Omnibus (GEO) database, including 26 OA samples and 20 normal samples. Via a series of bioinformatic analysis and machine learning, we identified the diagnostic biomarkers and several subtypes of OA. Moreover, the expression of these biomarkers were verified in our in-house cohort and the single cell dataset.

Results

Three significant regulators of disulfidptosis (NCKAP1, OXSM, and SLC3A2) were identified through differential expression analysis and machine learning. And a nomogram constructed based on these three regulators exhibited ideal efficiency in predicting early- and late-stage OA. Furthermore, based on the expression of three regulators, we identified two disulfidptosis-related subtypes of OA with different infiltration of immune cells and personalized expression level of immune checkpoints. Notably, the expression of the three regulators was demonstrated in a single-cell RNA profile and verified in the synovial tissue in our in-house cohort including 6 OA patients and 6 normal people. Finally, an efficient disulfidptosis-mediated diagnostic model was constructed for OA, with the AUC value of 97.6923% in the training set and 93.3333% and 100% in two validation sets.

Conclusion

Overall, with regard to PPPM, this study provided novel insights into the role of disulfidptosis regulators in the personalized diagnosis and treatment of OA.

Evidence for the use of cannabis-based medicines in osteoarthritis: a scoping review

The purpose of this study was to conduct a scoping review to describe the evidence on the efficacy and safety of using cannabis-based medicines for osteoarthritis. The review was conducted following the framework proposed by Arksey and O'Malley and reported following PRISMA extension for scoping reviews guidelines. We conducted a comprehensive search across various databases including MEDLINE, Embase, Cochrane Library, CINAHL, Scopus, and Proquest, spanning from inception of each database to March 2023. We retrieved 2533 citations, and after deduplication, title and abstract screening, and full-text screening, 10 articles were included for analysis. These studies were composed of randomized-controlled trials (n = 4/10), cross-sectional surveys (n = 3/10), case studies (n = 2/10), and a cohort study (n = 1/10). Evidence for using cannabis-based medicines was mixed, with just 60% (n = 6/10) of included studies reporting statistically significant improvements in pain. Studies with larger samples sizes and longer durations of exposure did not find significant benefits for pain. The few adverse effects reported were generally mild and affected a minority of participants. Several studies also discovered that cannabis-based medicines were associated with a reduction in opioid use. Currently available data on the use of cannabis-based medicines in osteoarthritis is insufficient to make recommendations. Future research should address concerns regarding small sample sizes and short treatment durations to provide a more robust evidence base. Key Points • Current evidence remains mixed; studies that found a positive benefit with using cannabis-based medicines had limitations with small sample sizes and short durations of exposure • The use of cannabis-based medicines in osteoarthritis appears to be generally well tolerated, adverse effects are mild and experienced by a minority of participants • Cannabis-based medicines may decrease the use of opioids in patients with osteoarthritis • Future research should address the gaps in long-term efficacy and safety data.

In vitro and in vivo studies of the therapeutic potential of Tinospora crispa extracts in osteoarthritis: Targeting oxidation, inflammation, and chondroprotection

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing incidence of osteoarthritis (OA), especially among the elderly population, highlights the need for more efficacious treatments that go beyond mere symptomatic relief. Tinospora crispa (L.) Hook. f. & Thomson (TC) boasts a rich traditional heritage, widespread use in Ayurveda, traditional Chinese medicine (TCM), and diverse indigenous healing practices throughout Southeast Asia for treating arthritis, rheumatism, fever, and inflammation.

AIM OF THE STUDY

This study investigates the anti-inflammatory and chondroprotective potential of TC stem extracts, including ethanolic TC extract (ETCE) and aqueous TC extract (ATCE), in modulating OA pathogenesis through in vitro and in vivo approaches.

MATERIALS AND METHODS

The study utilized LC-MS/MS to identify key compounds in TC stem extracts. In vitro experiments assessed the antioxidative and anti-inflammatory properties of ETCE and ATCE in activated macrophages, while an in vivo monoiodoacetate (MIA)-induced OA rat model evaluated the efficacy of ETCE treatment. Key markers of oxidative stress, such as superoxide dismutase (SOD) and catalase (CAT), were assessed alongside pro-inflammatory cytokines TNF-α and IL-1β, and matrix-degrading enzymes, matrix metalloproteinase (MMP 13 and MMP 3), to evaluate the therapeutic effects of TC stem extracts on OA.

RESULTS

Chemical profiling of the extracts was conducted using LC-MS/MS in positive ionization, identifying seven compounds, including pseudolaric acid B, stylopine, and reticuline, which were reported for the first time in this species. The study utilized varying concentrations of TC stem extracts, specifically 6.25-25 μg/mL for in vitro assays and 500 mg/kg for in vivo studies. Our findings also revealed that both ETCE and ATCE exhibit dose-dependent reduction in reactive oxygen species (41%-52%) and nitric oxide (NO) levels (50% and 72%), with ETCE displaying superior antioxidative efficacy and marked anti-inflammatory properties, significantly reducing TNF-α and IL-6 at concentrations above 12.5 μg/mL. In the MIA-induced OA rat model, ETCE treatment notably outperformed ATCE, markedly lowering TNF-α (1.91 ± 0.37 pg/mL) and IL-1β (26.30 ± 3.68 pg/mL) levels and effectively inhibiting MMP 13 and MMP 3 enzymes. Furthermore, macroscopic and histopathological assessments, including ICRS scoring and OARSI grading, indicate that TC stem extracts reduce articular damage and proteoglycan loss in rat knee cartilage. These results suggest that TC stem extracts may play a role in preventing cartilage degradation and potentially alleviating inflammation and pain associated with OA, though further studies are needed to confirm these effects.

CONCLUSION

This study highlights the potential of TC stem extracts as a novel, chondroprotective therapeutic avenue for OA management. By targeting oxidative stress, pro-inflammatory cytokines, and cartilage-degrading enzymes, TC stem extracts promise to prevent cartilage degradation and alleviate inflammation and pain associated with OA.

Sappanone a alleviates osteoarthritis progression by inhibiting chondrocyte ferroptosis via activating the SIRT1/Nrf2 signaling pathway

Osteoarthritis (OA) is a common degenerative joint disease that cause pain and disability in adults. Chondrocyte ferroptosis is found to be involved in OA progression. Sappanone A has been found as an anti-inflammatory and antioxidative agent in several diseases. This study aims to investigate the effects of sappanone A on OA progression and chondrocyte ferroptosis. IL-1β-induced chondrocytes and destabilization of the medial meniscus (DMM)-induced rats were respectively used as the OA model in vitro and in vivo. The effects of sappanone A on inflammation, extracellular matrix (ECM) metabolism, and ferroptosis were determined. Our results showed that in IL-1β-induced chondrocytes, sappanone A suppressed the production of NO, PGE2, TNF-α, IL-6, iNOS, and COX2. Sappanone A also inhibited the expression of MMP3, MMP13, and ADAMTS5, while increasing collagen II expression. Moreover, sappanone A alleviated cytotoxicity and decreased the levels of intracellular ROS, lipid ROS, MDA, and iron, while increasing GSH levels. Additionally, sappanone A increased the protein expression of SLC7A11 and GPX4. Administration of ferroptosis activator reversed the inhibitory effects of sappanone A on IL-1β-induced inflammation and ECM degradation. More importantly, Sappanone A activated the Nrf2 signaling by targeting SIRT1. The inhibition of sappanone A on ferroptosis was greatly eliminated due to the addition of SIRT1 inhibitor. Furthermore, intra-articular injection of sappanone A mitigated cartilage destruction and ferroptosis in DMM-induced OA rats. In conclusion, sappanone A protects against inflammation and ECM degradation in OA via decreasing chondrocyte ferroptosis by activating the SIRT1/Nrf2 signaling. These findings deepen our understanding of chondrocyte ferroptosis in OA and highlight the therapeutic potential of sappanone A for OA.

siRNA therapy in osteoarthritis: targeting cellular pathways for advanced treatment approaches

Osteoarthritis (OA) is a common joint disorder characterized by the degeneration of cartilage and inflammation, affecting millions worldwide. The disease's complex pathogenesis involves various cell types, such as chondrocytes, synovial cells, osteoblasts, and immune cells, contributing to the intricate interplay of factors leading to tissue degradation and pain. RNA interference (RNAi) therapy, particularly through the use of small interfering RNA (siRNA), emerges as a promising avenue for OA treatment due to its capacity for specific gene silencing. siRNA molecules can modulate post-transcriptional gene expression, targeting key pathways involved in cellular proliferation, apoptosis, senescence, autophagy, biomolecule secretion, inflammation, and bone remodeling. This review delves into the mechanisms by which siRNA targets various cell populations within the OA milieu, offering a comprehensive overview of the potential therapeutic benefits and challenges in clinical application. By summarizing the current advancements in siRNA delivery systems and therapeutic targets, we provide a solid theoretical foundation for the future development of novel siRNA-based strategies for OA diagnosis and treatment, paving the way for innovative and more effective approaches to managing this debilitating disease.

Inhibition of CC chemokine receptor 1 ameliorates osteoarthritis in mouse by activating PPAR-γ

BACKGROUND

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage destruction and inflammation. CC chemokine receptor 1 (CCR1), a member of the chemokine family and its receptor family, plays a role in the autoimmune response. The impact of BX471, a specific small molecule inhibitor of CCR1, on CCR1 expression in cartilage and its effects on OA remain underexplored.

METHODS

This study used immunohistochemistry (IHC) to assess CCR1 expression in IL-1β-induced mouse chondrocytes and a medial meniscus mouse model of destabilization of the medial meniscus (DMM). Chondrocytes treated with varying concentrations of BX471 for 24 h were subjected to IL-1β (10 ng/ml) treatment. The levels of the aging-related genes P16INK4a and P21CIP1 were analyzed via western blotting, and senescence-associated β-galactosidase (SA-β-gal) activity was measured. The expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), aggrecan (AGG), and the transcription factor SOX9 were determined through western blotting and RT‒qPCR. Collagen II, matrix metalloproteinase 13 (MMP13), and peroxisome proliferator-activated receptor (PPAR)-γ expression was analyzed via western blot, RT‒qPCR, and immunofluorescence. The impact of BX471 on inflammatory metabolism-related proteins under PPAR-γ inhibition conditions (using GW-9662) was examined through western blotting. The expression of MAPK signaling pathway-related molecules was assessed through western blotting. In vivo, various concentrations of BX471 or an equivalent medium were injected into DMM model joints. Cartilage destruction was evaluated through Safranin O/Fast green and hematoxylin-eosin (H&E) staining.

RESULTS

This study revealed that inhibiting CCR1 mitigates IL-1β-induced aging, downregulates the expression of iNOS, COX-2, and MMP13, and alleviates the IL-1β-induced decrease in anabolic indices. Mechanistically, the MAPK signaling pathway and PPAR-γ may be involved in inhibiting the protective effect of CCR1 on chondrocytes. In vivo, BX471 protected cartilage in a DMM model.

CONCLUSION

This study demonstrated the expression of CCR1 in chondrocytes. Inhibiting CCR1 reduced the inflammatory response, alleviated cartilage aging, and retarded degeneration through the MAPK signaling pathway and PPAR-γ, suggesting its potential therapeutic value for OA.

Unveiling myricetin's pharmacological potency: A comprehensive exploration of the molecular pathways with special focus on PI3K/AKT and Nrf2 signaling

Myricetin can be found in the traditional Chinese medicinal plant, Myrica rubra. Myricetin is a flavonoid that is present in many vegetables, fruits, and plants and is considered to have strong antioxidant properties as well as a wide range of therapeutic applications. Growing interest has been piqued by its classification as a polyphenolic molecule because of its potential therapeutic benefits in both the prevention and management of numerous medical conditions. To clarify myricetin's traditional medical uses, modern research has investigated various pharmacological effects such as antioxidant, anticancer, anti-inflammation, antiviral, antidiabetic, immunomodulation, and antineurodegenerative effects. Myricetin shows promise as a nutritional flavonol that could be beneficial in the prevention and mitigation of prevalent health conditions like diabetes, cognitive decline, and various types of cancer in humans. The findings included in this study indicate that myricetin has a great deal of promise for application in the formulation of medicinal products and nutritional supplements since it affects several enzyme activities and alters inflammatory markers. However, comprehensive preclinical studies and research studies are necessary to lay the groundwork for assessing myricetin's possible effectiveness in treating these long-term ailments. This review summarizes both in vivo and in vitro studies investigating myricetin's possible interactions through the nuclear factor-E2-related factor 2 (Nrf2) as well as PI3K (phosphatidylinositol 3-kinase)/AKT (protein kinase B) signaling pathways in an attempt to clarify the compound's possible clinical applicability across a range of disorders.

Lipids and lipid metabolism in cellular senescence: Emerging targets for age-related diseases

Cellular senescence is a kind of cellular state triggered by endogenous or exogenous stimuli, which is mainly characterized by stable cell cycle arrest and complex senescence-associated secretory phenotype (SASP). Once senescent cells accumulate in tissues, they may eventually accelerate the progression of age-related diseases, such as atherosclerosis, osteoarthritis, chronic lung diseases, cancers, etc. Recent studies have shown that the disorders of lipid metabolism are not only related to age-related diseases, but also regulate the cellular senescence process. Based on existing research evidences, the changes in lipid metabolism in senescent cells are mainly concentrated in the metabolic processes of phospholipids, fatty acids and cholesterol. Obviously, the changes in lipid-metabolizing enzymes and proteins involved in these pathways play a critical role in senescence. However, the link between cellular senescence, changes in lipid metabolism and age-related disease remains to be elucidated. Herein, we summarize the lipid metabolism changes in senescent cells, especially the senescent cells that promote age-related diseases, as well as focusing on the role of lipid-related enzymes or proteins in senescence. Finally, we explore the prospect of lipids in cellular senescence and their potential as drug targets for preventing and delaying age-related diseases.

Assessing the degree to which randomized controlled trials align with the core outcome set for osteoarthritis of knee and hip: A cross-sectional analysis

OBJECTIVE

To assess the degree of core outcome set alignment and identify issues with alignment to the 2019 COS among clinical trial registrations focused on knee and/or hip osteoarthritis (OA).

METHODS

Our search was performed on registered knee and hip OA randomized controlled trials (RCTs) available on ClinicalTrials.gov and WHO International Clinical Trials Registry Platform. The screening process considered trials registered between 8/2014 and 6/2023. We extracted data on general trial characteristics and the five trial endpoints detailed in the COS (pain, physical function, quality of life, patient global assessment, and adverse events), in a masked and duplicate manner. The frequencies of COS alignment were assessed over time prior to and after COS publication.

RESULTS

Of the 10,718 RCTs screened, 481 met inclusion criteria. Most were phase 3 (368/481, 76.51%) and heavily university-funded (184/481, 38.25%). Despite the 2019 COS, no marked enhancement in overall alignment was noted. The outcome 'Pain' exhibited the highest degree of COS alignment (455/481, 94.59%), whereas 'adverse events' lagged behind (89/481, 18.50%). Additionally, trial factors such as 'Continent', 'Funding Type', and 'Recruitment Status' displayed no significant influence on COS alignment.

CONCLUSIONS

Despite the acknowledged advantages of using COS in RCTs and the availability of an updated COS, the alignment to these outcomes remains notably low. Significant efforts are needed to encourage broader adoption in future studies on knee and hip OA, with the aim of improving research quality and patient care.

Research progress on nanotechnology of traditional Chinese medicine to enhance the therapeutic effect of osteoarthritis

Osteoarthritis (OA) is a prevalent chronic condition that primarily impacts the articular cartilage and surrounding bone tissue, resulting in joint inflammation and structural deterioration. The etiology of OA is multifaceted and intricately linked to the oxidative stress response of joint tissue. Oxidative stress (OS) in OA leads to the creation of reactive oxygen species (ROS) and other oxidizing agents, resulting in detrimental effects on chondrocytes. This oxidative damage diminishes the flexibility and robustness of cartilage, thereby expediting the progression of joint deterioration. Therefore, the antioxidant effect is crucial in the treatment of OA. Currently, a considerable number of components found in traditional Chinese medicine (TCM) have been scientifically demonstrated to exhibit remarkable antioxidant and anti-inflammatory properties. Nevertheless, the utilization of this program is considerably constrained as a result of intrinsic deficiencies, notably stability concerns. The successful amalgamation of TCM components with nanotechnology has properly tackled these concerns and enhanced the efficacy of therapeutic results. The objective of this study is to delineate the antioxidant characteristics of nano-TCM and assess the current inventory of literature pertaining to the application of nano-TCM in the treatment of OA. In conclusion, this paper will now turn to the constraints and potential avenues for the advancement of nano-TCM within the realm of OA therapy.

The role of monocyte/macrophage chemokines in pathogenesis of osteoarthritis: A review

Osteoarthritis (OA) is one of the most common degenerative diseases characterised by joint pain, swelling and decreased mobility, with its main pathological features being articular synovitis, cartilage degeneration and osteophyte formation. Inflammatory cytokines and chemokines secreted by activated immunocytes can trigger various inflammatory and immune responses in articular cartilage and synovium, contributing to the genesis and development of OA. A series of monocyte/macrophage chemokines, including monocyte chemotaxis protein (MCP)-1/CCL2, MCP2/CCL8, macrophage inflammatory protein (MIP)-1α/CCL3, MIP-1β/CCL4, MIP-3α/CCL20, regulated upon activation, normal T-cell expressed and secreted /CCL5, CCL17 and macrophage-derived chemokine/CCL22, was proven to transmit cell signals by binding to G protein-coupled receptors on recipient cell surface, mediating and promoting inflammation in OA joints. However, the underlying mechanism of these chemokines in the pathogenesis of OA remains still elusive. Here, published literature was reviewed, and the function and mechanisms of monocyte/macrophage chemokines in OA pathogenesis were summarised. The symptoms and disease progression of OA were found to be effectively alleviated when the expression of these chemokines is inhibited. Elucidating these mechanisms could contribute to further understand how OA develops and provide potential targets for the early diagnosis of arthritis and drug treatment to delay or even halt OA progression.

Client and clinician perspectives about a virtual education and exercise chronic disease management programme for people with hip and knee osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is one of the most prevalent chronic conditions in Canada. Despite the established benefits of non-pharmacological management (education, exercise) for people with OA, many do not receive treatment, resulting in pain, decreased physical function, and poorer quality of life. Virtual programme options grew significantly during the recent pandemic and may provide longer-term opportunities for increased uptake by reaching individuals otherwise unable to participate. This study explored the experiences and perspectives of clients participating in and clinicians providing the Good Life with osteoArthritis: Denmark (GLA:DTM) Canada remote programme.

METHODS

This qualitative descriptive study recruited 10 clients with hip and/or knee OA and 11 clinicians across Canada using purposive sampling. An online pre-interview survey was completed, and individual interviews were conducted, audio-recorded, transcribed verbatim and analysed independently by two researchers using inductive thematic analysis. Coding and analyses were initially conducted separately by group and then compared and combined.

RESULTS

Four overarching themes (and 11 subthemes) were identified: (1) Expected and unexpected benefits of virtual programs; (2) Drawbacks to virtual programs; (3) Programme delivery in a virtual world; (4) Shifting and non-shifting perspectives. Although initially sceptical, after completion of the programme, clients were in favour of virtual delivery with many benefits described. Clinicians' perspectives varied about feedback aimed to correct client movement patterns.

CONCLUSIONS

Clients and clinicians identified important experiential and procedural elements for virtual chronic disease management programs that include education and exercise. Additional work is needed to understand if the GLA:DTM remote outcomes are equivalent to the in-person programme.

Integrated bioinformatics analysis identified leucine rich repeat containing 15 and secreted phosphoprotein 1 as hub genes for calcific aortic valve disease and osteoarthritis

Calcific aortic valve disease (CAVD) and osteoarthritis (OA) are common diseases in the ageing population and share similar pathogenesis, especially in inflammation. This study aims to discover potential diagnostic and therapeutic targets in patients with CAVD and OA. Three CAVD datasets and one OA dataset were obtained from the Gene Expression Omnibus database. We used bioinformatics methods to search for key genes and immune infiltration, and established a ceRNA network. Immunohistochemical staining was performed to verify the expression of candidate genes in human and mice aortic valve tissues. Two key genes obtained, leucine rich repeat containing 15 (LRRC15) and secreted phosphoprotein 1 (SPP1), were further screened using machine learning and verified in human and mice aortic valve tissues. Compared to normal tissues, the infiltration of immune cells in CAVD tissues was significantly higher, and the expressions of LRRC15 and SPP1 were positively correlated with immune cells infiltration. Moreover, the ceRNA network showed extensive regulatory interactions based on LRRC15 and SPP1. The authors' findings identified LRRC15 and SPP1 as hub genes in immunological mechanisms during CAVD and OA initiation and progression, as well as potential targets for drug development.

Icariin inhibits chondrocyte ferroptosis and alleviates osteoarthritis by enhancing the SLC7A11/GPX4 signaling

BACKGROUND

Chondrocyte ferroptosis plays a critical role in the pathogenesis of osteoarthritis (OA), regulated by the SLC7A11/GPX4 signaling pathway. Icariin (ICA), a flavonoid glycoside, exhibits strong anti-inflammatory and antioxidant activities. This study investigated whether ICA could modulate the SLC7A11/GPX4 signaling to inhibit chondrocyte ferroptosis and alleviate OA.

PURPOSE

The objective was to explore the impact of ICA on chondrocyte ferroptosis in OA and its modulation of the SLC7A11/GPX4 signaling pathway.

METHODS

The anti-ferroptosis effects of ICA were evaluated in an interleukin-1β (IL-1β)-treated SW1353 cell model, using Ferrostatin-1 (Fer-1) and Erastin (Era) as ferroptosis inhibitor and inducer, respectively, along with GPX4 knockdown via lentivirus-based shRNA. Additionally, the therapeutic efficacy of ICA on OA-related articular cartilage damage was assessed in rats through histopathology and immunohistochemistry (IHC).

RESULTS

IL-1β treatment upregulated the expression of OA-associated matrix metalloproteinases (MMP3 and MMP1), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-5), and increased intracellular ROS, lipid ROS, and MDA levels while downregulating collagen II and SOX9 expression in SW1353 cells. ICA treatment countered the IL-1β-induced upregulation of MMPs and ADAMTS-5, restored collagen II and SOX9 expression, and reduced intracellular ROS, lipid ROS, and MDA levels. Furthermore, IL-1β upregulated P53 but downregulated SLC7A11 and GPX4 expression in SW1353 cells, effects that were mitigated by ICA or Fer-1 treatment. Significantly, ICA also alleviated Era-induced ferroptosis, whereas it had no effect on GPX4-silenced SW1353 cells. In vivo, ICA treatment reduced articular cartilage damage in OA rats by partially restoring collagen II and GPX4 expression, inhibiting cartilage extracellular matrix (ECM) degradation and chondrocyte ferroptosis.

CONCLUSION

ICA treatment mitigated chondrocyte ferroptosis and articular cartilage damage by enhancing the SLC7A11/GPX4 signaling, suggesting its potential as a therapeutic agent for OA interventions.

Omega-3 Supplementation and Its Effects on Osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease characterized by the destruction of the articular cartilage, resulting in a pro-inflammatory response. The progression of OA is multifactorial and is influenced by the underlying cause of inflammation, which includes but is not limited to trauma, metabolism, biology, comorbidities, and biomechanics. Although articular cartilage is the main tissue affected in osteoarthritis, the chronic inflammatory environment negatively influences the surrounding synovium, ligaments, and subchondral bone, further limiting their functional abilities and enhancing symptoms of OA. Treatment for osteoarthritis remains inconsistent due to the inability to determine the underlying mechanism of disease onset, severity of symptoms, and complicating comorbidities. In recent years, diet and nutritional supplements have gained interest regarding slowing the disease process, prevention, and treatment of OA. This is due to their anti-inflammatory properties, which result in a positive influence on pain, joint mobility, and cartilage formation. More specifically, omega-3 polyunsaturated fatty acids (PUFA) have demonstrated an influential role in the progression of OA, resulting in the reduction of cartilage destruction, inhibition of pro-inflammatory cytokine cascades, and production of oxylipins that promote anti-inflammatory pathways. The present review is focused on the assessment of evidence explaining the inflammatory processes of osteoarthritis and the influence of omega-3 supplementation to modulate the progression of osteoarthritis.

The burden of knee osteoarthritis worldwide, regionally, and nationally from 1990 to 2019, along with an analysis of cross-national inequalities

OBJECTIVE

To describe the disease burden of knee osteoarthritis (KOA) globally, regionally, and in 204 countries by age, sex, and sociodemographic index (SDI) from 1990 to 2019, and to explore cross-national inequalities across SDI.

METHODS

The Global Burden of Disease (GBD) 2019 database collected data on KOA worldwide from 1990 to 2019, including prevalence, incidence, years lived with disability (YLDs). The average annual percentage change (AAPC) was used to measure temporal trends. In addition, the inequality slope index and the health concentration index were calculated to quantify the unequal distribution of the burden of KOA across 204 countries worldwide.

RESULTS

In 2019, the global age-standardized prevalence rate increased by 7.5% compared with 1990, and the age-standardized incidence rate increased by about 6.2%; The age-standardized YLDs rate increased by about 7.8%. In addition to the Republic of Korea and the United States of America, the disease burden of KOA has increased year by year in other countries around the world. The incidence of KOA was highest at ages 50-59, while the prevalence and rates of YLDs were highest at ages 75-84. The burden of KOA was higher in women than in men. Cross-country inequality suggests that the inequality in the burden of KOA between high SDI and low SDI countries becomes greater, and that countries with high SDI bear a disproportionately high burden.

CONCLUSION

The global KOA burden has risen steadily between 1990 and 2019, and cross-national inequality gaps remain large. Targeted measures must therefore be taken to address this inequality and the increasing global KOA disease burden.

Unraveling the path to osteoarthritis management: targeting chondrocyte apoptosis for therapeutic intervention

Osteoarthritis (OA) is a chronic disease affecting joints and further causing disabilities. This disease affects around 240 million people worldwide. It is a multifactorial disease, and its etiology is difficult to determine. Although numerous therapeutic strategies are available, the therapies are aimed at reducing pain and improving patients' quality of life. Hence, there is an urgent need to develop disease-modifying drugs (DMOAD) that can reverse or halt OA progression. Apoptosis is a cell removal process that is important in maintaining homeostatic mechanisms in the development and sustaining cell population. The apoptosis of chondrocytes is believed to play an important role in OA progression due to poor chondrocytes self-repair abilities to maintain the extracellular matrix (ECM). Hence, targeting chondrocyte apoptosis can be one of the potential therapeutic strategies in OA management. There are various mediators and targets available to inhibit apoptosis such as autophagy, endoplasmic reticulum (ER) stress, oxidative stress, and inflammation. As such, this review highlights the importance and potential targets that can be aimed to reduce chondrocyte apoptosis.

PUM2 promoted osteoarthritis progression through PTEN-mediated chondrocyte ferroptosis by facilitating NEDD4 mRNA degradation

Osteoarthritis (OA) is a prevalent degenerative joint disease with a lack of effective therapeutic. Chondrocyte ferroptosis contributes to the progression of OA. PUM2 is shown to exacerbate ischemia-reperfusion-induced neuroinflammation by promoting ferroptosis, but its role in OA remains unexplored. Here, primary mouse chondrocytes were stimulated with IL-1β to mimic OA chondrocyte injury in vitro. And PUM2 was upregulated in OA cartilage tissues and IL-1β-induced chondrocytes. Silencing PUM2 alleviated IL-1β-induced chondrocyte inflammation and ECM degradation. Mechanistically, PUM2 facilitated the degradation of NEDD4 mRNA by binding to the 3'UTR of NEDD4 mRNA, which in turn inhibited NEDD4 induced PTEN ubiquitination and degradation. Consistently, NEDD4 silencing reversed the ameliorative effect of PUM2 knockdown on chondrocyte injury, and overexpression of PTEN abolished the improved role of NEDD4 in chondrocyte injury. Moreover, PTEN aggravated IL-1β-induced ferroptosis in chondrocytes through the Nrf2/HO-1 pathway by increasing the levels of Fe2+, ROS, MDA, and ACSL4 protein, decreasing the activity of SOD and the levels of GSH and GPX4 protein, and aggravating mitochondrial damage. Additionally, destabilized medial meniscus (DMM) were conducted to establish the OA mouse model, and adenovirus-mediated PUM2 shRNA was administered intra-articularly. Silencing PUM2 attenuated OA-induced cartilage damage in vivo. In conclusion, PUM2 promoted OA progression through PTEN-mediated chondrocyte ferroptosis by facilitating NEDD4 mRNA degradation.

Orthopaedic surgeons' attitude toward physical activity for people after total hip or knee replacement: Northern vs Southern European country

BACKGROUND

Regular physical activity (PA) is a key factor of lifestyle behavior enhancing general health and fitness, especially in people after total hip or knee replacement (THR and TKR). Orthopaedic surgeons can play a primary role in advocating the benefits of an active lifestyle. Aim of the study was 1) to assess the attitude of orthopaedic surgeons towards PA for people after THR/TKR and 2) to compare the attitude between a Northern European (the Netherlands) and a Southern European (Italy) country and analyze which factors influence the attitude towards PA.

METHODS

A cross-cultural study. An (online) survey was distributed among orthopaedic surgeons in Italy and the Netherlands. Chi-square and Mann-Whitney tests were used to compare surgeons' and clinics' characteristics, and questionnaires' scores, respectively. A linear regression analysis was conducted to assess which surgeon characteristics influence attitude towards PA.

RESULTS

A cohort of 159 surgeons (103 Italians and 56 Dutch) was analyzed. The median score of overall orthopaedic surgeons' attitude towards PA was positive (57 out of 72). Dutch surgeons showed a more positive attitude compared to Italian surgeons (p < 0.01). Main difference was found in the "Physical activity concern" factor, where Italian surgeons showed more concern about the negative effects of PA on the survival of the prosthesis. The regression analyses showed that "Country" and "Type of clinic" were associated with the surgeons' attitude.

CONCLUSIONS

Overall, the orthopaedic surgeons' attitude towards PA for people with THR and TKR was positive. However, Dutch surgeons seem to be more positive compared to the Italian. The country of residence was the item that most influenced attitude. Further investigations are needed to untangle specific factors, such as cultural, socioeconomic, or contextual differences within the variable "country" that may influence orthopaedic surgeons' attitudes towards PA.

Correlation of meniscus tear type with synovial inflammation and the therapeutic potential of docosapentaenoic acid

BACKGROUND

Synovitis, characterized by inflammation of the synovial membrane, is commonly induced by meniscus tears. However, significant differences in inflammatory responses and the key inflammatory mediators of synovium induced by different types of meniscal tears remain unclear.

METHODS

Magnetic resonance imaging (MRI) was employed to identify the type of meniscus tear, and the quantification of synovial inflammation was assessed through H&E staining assay. Transcription and expression levels of IL-1β and IL-6 were evaluated using bioinformatics, ELISA, RT-qPCR, and IHC of CD68 staining assays. The therapeutic potential of Docosapentaenoic Acid (DPA) was determined through network pharmacology, ELISA, and RT-qPCR assays. The safety of DPA was assessed using colony formation and EdU staining assays.

RESULTS

The results indicate that both IL-1β and IL-6 play pivotal roles in synovitis pathogenesis, with distinct expression levels across various subtypes. Among tested meniscus tears, oblique tear and bucket handle tear induced the most severe inflammation, followed by radial tear and longitudinal tear, while horizontal tear resulted in the least inflammation. Furthermore, in synovial inflammation induced by specific meniscus tears, the anterior medial tissues exhibited significantly higher local inflammation than the anterior lateral and suprapatellar regions, highlighting the clinical relevance and practical guidance of anterior medial tissues' inflammatory levels. Additionally, we identified the essential omega-3 fatty acid DPA as a potential therapeutic agent for synovitis, demonstrating efficacy in blocking the transcription and expression of IL-1β and IL-6 with minimal side effects.

CONCLUSION

These findings provide valuable insights into the nuanced nature of synovial inflammation induced by various meniscal tear classifications and contribute to the development of new adjunctive therapeutic agents in the management of synovitis.

Novel insights into the role of ubiquitination in osteoarthritis

Ubiquitination (Ub) and deubiquitination are crucial post-translational modifications (PTMs) that precisely regulate protein degradation. Under the catalysis of a cascade of E1-E2-E3 ubiquitin enzymes, ubiquitination extensively regulates protein degradation exerting direct impact on various cellular processes, while deubiquitination opposes the effect of ubiquitination and prevents proteins from degradation. Notably, such dynamic modifications have been widely investigated to be implicated in cell cycle, transcriptional regulation, apoptosis and so on. Therefore, dysregulation of ubiquitination and deubiquitination could lead to certain diseases through abnormal protein accumulation and clearance. Increasing researches have revealed that the dysregulation of catalytic regulators of ubiquitination and deubiquitination triggers imbalance of cartilage homeostasis that promotes osteoarthritis (OA) progression. Hence, it is now believed that targeting on Ub enzymes and deubiquitinating enzymes (DUBs) would provide potential therapeutic pathways. In the following sections, we will summarize the biological role of Ub enzymes and DUBs in the development and progression of OA by focusing on the updating researches, with the aim of deepening our understanding of the underlying molecular mechanism of OA pathogenesis concerning ubiquitination and deubiquitination, so as to explore novel potential therapeutic targets of OA treatment.

Distinctiveness of Femoral and Acetabular Mesenchymal Stem and Progenitor Populations in Patients with Primary and Secondary Hip Osteoarthritis Due to Developmental Dysplasia

Primary hip osteoarthritis (pOA) develops without an apparent underlying reason, whereas secondary osteoarthritis arises due to a known cause, such as developmental dysplasia of the hips (DDH-OA). DDH-OA patients undergo total hip arthroplasty at a much younger age than pOA patients (50.58 vs. 65 years in this study). Recently, mesenchymal stem and progenitor cells (MSPCs) have been investigated for the treatment of osteoarthritis due to their immunomodulatory and regenerative potential. This study identified cells in subchondral bone expressing common MSPC markers (CD10, CD73, CD140b, CD146, CD164, CD271, GD2, PDPN) in vivo and compared the proportions of these populations in pOA vs. DDH-OA, further correlating them with clinical, demographic, and morphological characteristics. The differences in subchondral morphology and proportions of non-hematopoietic cells expressing MSPC markers were noted depending on OA type and skeletal location. Bone sclerosis was more prominent in the pOA acetabulum (Ac) in comparison to the DDH-OA Ac and in the pOA Ac compared to the pOA femoral head (Fh). Immunophenotyping indicated diagnosis-specific differences, such as a higher proportion of CD164+ cells and their subsets in DDH-OA, while pOA contained a significantly higher proportion of CD10+ and GD2+ cells and subsets, with CD271+ being marginally higher. Location-specific differences showed that CD271+ cells were more abundant in the Fh compared to the Ac in DDH-OA patients. Furthermore, immunohistochemical characterization of stromal bone-adjacent cells expressing MSPC markers (CD10, CD164, CD271, GD2) in the Ac and Fh compartments was performed. This research proved that immunophenotype profiles and morphological changes are both location- and disease-specific. Furthermore, it provided potentially effective targets for therapeutic strategies. Future research should analyze the differentiation potential of subsets identified in this study. After proper characterization, they can be selectively targeted, thus enhancing personalized medicine approaches in joint disease management.

Circulating Copper Is Associated with Inflammatory Biomarkers in Greek Older Adults with Osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis, that causes a significant decrease in the quality of life of the afflicted and constitutes a great burden for the socioeconomic system. Trace elements and heavy metals are implicated in the pathophysiology of OA, exacerbating inflammatory and oxidative stress responses. The aim of this cross-sectional study was to quantify metals in plasma samples of Greek OA patients and explore their link with disease related parameters, health status or quality of life, as well as epigenetic OA markers. This is the first study on plasma metal levels in Greek knee OA patients. To achieve precision in plasma metal and miRNA measurements, high-quality samples were selected from a subset of 34 participants (NCT04783792). Demographic, quality of life, clinical, biochemical, inflammation, oxidative stress, and anthropometric parameters, as well as microRNA levels were assessed. Significant correlations were found between circulating metals with OA related parameters or with measured microRNAs. Also, significant positive associations between plasma copper (Cu) levels and CRP (p = 0.033) or IL-6 (p = 0.001) occurred when adjusting for age, gender, BMI, physical activity level, smoking, disease severity, total arthroplasty, and dietary intake of the respective metal. Cu's role in OA is bidirectional, and this study confirms the findings that in OA, Cu is positively associated with inflammation. Such relationships between lifestyle, environment and OA enhance our understanding and encourage further study on metals related to OA inflammation.

Hybrid triboelectric-piezoelectric nanogenerator for long-term load monitoring in total knee replacements

A self-powered and durable pressure sensor for large-scale pressure detection on the knee implant would be highly advantageous for designing long-lasting and reliable knee implants as well as obtaining information about knee function after the operation. The purpose of this study is to develop a robust energy harvester that can convert wide ranges of pressure to electricity to power a load sensor inside the knee implant. To efficiently convert loads to electricity, we design a cuboid-array-structured tribo-pizoelectric nanogenerator (TPENG) in vertical contact mode inside a knee implant package. The proposed TPENG is fabricated with aluminum and cuboid-patterned silicone rubber layers. Using the cuboid-patterned silicone rubber as a dielectric and aluminum as electrodes improves performance compared with previously reported self-powered sensors. The combination of 10w t % dopamine-modified BaTiO3 piezoelectric nanoparticles in the silicone rubber enhanced electrical stability and mechanical durability of the silicone rubber. To examine the output, the package-harvester assemblies are loaded into an MTS machine under different periodic loading. Under different cyclic loading, frequencies, and resistance loads, the harvester's output performance is also theoretically studied and experimentally verified. The proposed cuboid-array-structured TPENG integrated into the knee implant package can generate approximately 15μ W of apparent power under dynamic compressive loading of 2200 N magnitude. In addition, as a result of the TPENG's materials being effectively optimized, it possesses remarkable mechanical durability and signal stability, functioning after more than 30 000 cycles under 2200 N load and producing about 300 V peak to peak. We have also presented a mathematical model and numerical results that closely capture experimental results. We have reported how the TPENG charge density varies with force. This study represents a significant advancement in a better understanding of harvesting mechanical energy for instrumented knee implants to detect a load imbalance or abnormal gait patterns.

Hnrnpk protects against osteoarthritis through targeting WWC1 mRNA and inhibiting Hippo signaling pathway

Osteoarthritis (OA) is an age-related or post-traumatic degenerative whole joint disease characterized by the rupture of articular cartilage homeostasis, the regulatory mechanisms of which remain elusive. This study identifies the essential role of heterogeneous nuclear ribonucleoprotein K (hnRNPK) in maintaining articular cartilage homeostasis. Hnrnpk expression is markedly downregulated in human and mice OA cartilage. The deletion of Hnrnpk effectively accelerates the development of post-traumatic and age-dependent OA in mice. Mechanistically, the KH1 and KH2 domain of Hnrnpk bind and degrade the mRNA of WWC1. Hnrnpk deletion increases WWC1 expression, which in turn leads to the activation of Hippo signaling and ultimately aggravates OA. In particular, intra-articular injection of LPA and adeno-associated virus serotype 5 expressing WWC1 RNA interference ameliorates cartilage degeneration induced by Hnrnpk deletion, and intra-articular injection of adeno-associated virus serotype 5 expressing Hnrnpk protects against OA. Collectively, this study reveals the critical roles of Hnrnpk in inhibiting OA development through WWC1-dependent downregulation of Hippo signaling in chondrocytes and defines a potential target for the prevention and treatment of OA.

The role of dietary preferences in osteoarthritis: a Mendelian randomization study using genome-wide association analysis data from the UK Biobank

Background

To understand the impact of individual preferences for specific dietary items on OA, and to help inform the development of effective and targeted OA prevention and management strategies, we performed a Mendelian randomization analysis between dietary preferences and osteoarthritis.

Methods

This study utilized genetic data from the UK Biobank to investigate the association between OA and 21 different common dietary items. Instrumental variables representing European populations were carefully selected based on their genetic significance and linkage disequilibrium. In cases where a dietary item had few relevant genetic markers, a more lenient selection threshold was applied. To prevent bias, the analysis excluded single nucleotide polymorphisms (SNPs) associated with factors such as body mass index (BMI) and cholesterol. Using inverse-variance weighting (IVW) and Mendelian randomization, significant associations were detected between certain dietary items and OA.

Results

Using Mendelian randomization to examine the relationship between 21 different dietary items and OA, significant associations were found for coffee, peas, watercress, and cheese, where the first two had a promoting effect and the last two an inhibiting effect on OA. Due to heterogeneity in the test results for cheese, a random IVW representation was used. The results of sensitivity analysis showed no significant heterogeneity or horizontal pleiotropy in the selected SNPS, demonstrating the reliability of Mendelian randomization analysis.

Conclusion

This study identified coffee, peas, watercress, and cheese as food items that may have significant dietary effects on osteoarthritis. This information may be useful to consider in the development of OA management strategies.

Bergamottin (Ber) ameliorates the progression of osteoarthritis via the Sirt1/NF-κB pathway

Osteoarthritis (OA) is a common chronic disease characterized by progressive cartilage degeneration and secondary synovial inflammation. Bergamottin (Ber) is an important natural derivative of the furanocoumarin compound, extracted from natural foods, such as the pulp of grapefruits and pomelos. Ber exhibits several characteristicsthat are beneficial to human health, such as anti-inflammation, antioxidant, and anti-cancer effects. However, the role of Ber in the treatment of OA has not been elucidated to date. Therefore, in the present study, in vitro experiments were conducted, which demonstrated that Ber reduces the secretion of inducible nitric oxide synthase (iNOS), nitric oxide (NO), cyclooxygenase-2 (COX2), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and prostaglandin E2 (PGE2) under the stimulation of interleukin-1β (IL-1β). Ber also reversed the IL-1 β-mediated aggrecan and type II collagen degradation within the extracellular matrix (ECM). In addition, in vivo experiments were conducted, in which Ber ameliorated the progression of OA in mice. It was revealed that Ber exerted its cellular effect by activating the Sirt1/NF-kB pathways. In conclusion, the present study demonstrated the therapeutic potential of Ber in the context of OA.

Osteoarthritis: Insights into Diagnosis, Pathophysiology, Therapeutic Avenues, and the Potential of Natural Extracts

Osteoarthritis (OA) stands as a prevalent and progressively debilitating clinical condition globally, impacting joint structures and leading to their gradual deterioration through inflammatory mechanisms. While both non-modifiable and modifiable factors contribute to its onset, numerous aspects of OA pathophysiology remain elusive despite considerable research strides. Presently, diagnosis heavily relies on clinician expertise and meticulous differential diagnosis to exclude other joint-affecting conditions. Therapeutic approaches for OA predominantly focus on patient education for self-management alongside tailored exercise regimens, often complemented by various pharmacological interventions primarily targeting pain alleviation. However, pharmacological treatments typically exhibit short-term efficacy and local and/or systemic side effects, with prosthetic surgery being the ultimate resolution in severe cases. Thus, exploring the potential integration or substitution of conventional drug therapies with natural compounds and extracts emerges as a promising frontier in enhancing OA management. These alternatives offer improved safety profiles and possess the potential to target specific dysregulated pathways implicated in OA pathogenesis, thereby presenting a holistic approach to address the condition's complexities.

Advancing Tissue Damage Repair in Geriatric Diseases: Prospects of Combining Stem Cell-Derived Exosomes with Hydrogels

Geriatric diseases are a group of diseases with unique characteristics related to senility. With the rising trend of global aging, senile diseases now mainly include endocrine, cardiovascular, neurodegenerative, skeletal, and muscular diseases and cancer. Compared with younger populations, the structure and function of various cells, tissues and organs in the body of the elderly undergo a decline as they age, rendering them more susceptible to external factors and diseases, leading to serious tissue damage. Tissue damage presents a significant obstacle to the overall health and well-being of older adults, exerting a profound impact on their quality of life. Moreover, this phenomenon places an immense burden on families, society, and the healthcare system.In recent years, stem cell-derived exosomes have become a hot topic in tissue repair research. The combination of these exosomes with biomaterials allows for the preservation of their biological activity, leading to a significant improvement in their therapeutic efficacy. Among the numerous biomaterial options available, hydrogels stand out as promising candidates for loading exosomes, owing to their exceptional properties. Due to the lack of a comprehensive review on the subject matter, this review comprehensively summarizes the application and progress of combining stem cell-derived exosomes and hydrogels in promoting tissue damage repair in geriatric diseases. In addition, the challenges encountered in the field and potential prospects are presented for future advancements.

CHMP5 attenuates osteoarthritis via inhibiting chondrocyte apoptosis and extracellular matrix degradation: involvement of NF-κB pathway

BACKGROUND

Osteoarthritis (OA), the most common joint disease, is linked with chondrocyte apoptosis and extracellular matrix (ECM) degradation. Charged multivesicular body protein 5 (CHMP5), a member of the multivesicular body, has been reported to serve as an anti-apoptotic protein to participate in leukemia development. However, the effects of CHMP5 on apoptosis and ECM degradation in OA remain unclear.

METHODS

In this study, quantitative proteomics was performed to analyze differential proteins between normal and OA patient articular cartilages. The OA mouse model was constructed by the destabilization of the medial meniscus (DMM). In vitro, interleukin-1 beta (IL-1β) was used to induce OA in human chondrocytes. CHMP5 overexpression and silencing vectors were created using an adenovirus system. The effects of CHMP5 on IL-1β-induced chondrocyte apoptosis were investigated by CCK-8, flow cytometry, and western blot. The effects on ECM degradation were examined by western blot and immunofluorescence. The potential mechanism was explored by western blot and Co-IP assays.

RESULTS

Downregulated CHMP5 was identified by proteomics in OA patient cartilages, which was verified in human and mouse articular cartilages. CHMP5 overexpression repressed cell apoptosis and ECM degradation in OA chondrocytes. However, silencing CHMP5 exacerbated OA chondrocyte apoptosis and ECM degradation. Furthermore, we found that the protective effect of CHMP5 against OA was involved in nuclear factor kappa B (NF-κB) signaling pathway.

CONCLUSIONS

This study demonstrated that CHMP5 repressed IL-1β-induced chondrocyte apoptosis and ECM degradation and blocked NF-κB activation. It was shown that CHMP5 might be a novel potential therapeutic target for OA in the future.

Applications of Hydrogels in Osteoarthritis Treatment

This review critically evaluates advancements in multifunctional hydrogels, particularly focusing on their applications in osteoarthritis (OA) therapy. As research evolves from traditional natural materials, there is a significant shift towards synthetic and composite hydrogels, known for their superior mechanical properties and enhanced biodegradability. This review spotlights novel applications such as injectable hydrogels, microneedle technology, and responsive hydrogels, which have revolutionized OA treatment through targeted and efficient therapeutic delivery. Moreover, it discusses innovative hydrogel materials, including protein-based and superlubricating hydrogels, for their potential to reduce joint friction and inflammation. The integration of bioactive compounds within hydrogels to augment therapeutic efficacy is also examined. Furthermore, the review anticipates continued technological advancements and a deeper understanding of hydrogel-based OA therapies. It emphasizes the potential of hydrogels to provide tailored, minimally invasive treatments, thus highlighting their critical role in advancing the dynamic field of biomaterial science for OA management.

Single cell transcriptome profiling of infrapatellar fat pad highlights the role of interstitial inflammatory fibroblasts in osteoarthritis

OBJECTIVES

Osteoarthritis (OA) is a whole-joint disease in which the role of the infrapatellar fat pad (IFP) in its pathogenesis is unclear. Our study explored the cellular heterogeneity of IFP to understand OA and identify therapeutic targets.

METHODS

Single-cell and single-nuclei RNA sequencing were used to analyze 10 IFP samples, comprising 5 from OA patients and 5 from healthy controls. Analyses included differential gene expression, enrichment, pseudotime trajectory, and cellular communication, along with comparative studies with visceral and subcutaneous fats. Key subcluster and pathways were validated using multiplex immunohistochemistry.

RESULTS

The scRNA-seq performed on the IFPs of the OA and control group profiled the gene expressions of over 49,674 cells belonging to 11 major cell types. We discovered that adipose stem and progenitor cells (ASPCs), contributing to the formation of both adipocytes and synovial-lining fibroblasts (SLF). Interstitial inflammatory fibroblasts (iiFBs) were a subcluster of ASPCs that exhibit notable pro-inflammatory and proliferative characteristics. We identified four adipocyte subtypes, with one subtype showing a reduced lipid synthesis ability. Furthermore, iiFBs modulated the activities of macrophages and T cells in the IFP. Compared to subcutaneous and visceral adipose tissues, iiFBs represented a distinctive subpopulation of ASPCs in IFP that regulated cartilage proliferation through the MK pathway.

CONCLUSION

This study presents a comprehensive single-cell transcriptomic atlas of IFP, uncovering its complex cellular landscape and potential impact on OA progression. Our findings highlight the role of iiFBs in OA, especially through MK pathway, opening new avenues for understanding OA pathogenesis and developing novel targeted therapies.

Toll-like receptor activation regulates the paracrine effect of adipose-derived mesenchymal stem cells on reversing osteoarthritic phenotype of chondrocytes

BACKGROUND

The therapeutic efficacy of intra-articular mesenchymal stem cells (MSCs) injection for patients with osteoarthritis (OA) currently exhibits inconsistency, and the underlying mechanism remains elusive. It has been postulated that the immunomodulatory properties and paracrine activity of MSCs might be influenced by the inflammatory micro-environment within osteoarthritic joints, potentially contributing to this observed inconsistency.

METHODS

Adipose-derived MSCs (ADSCs) were isolated from SD rats and pre-treated with Toll-like receptor 3 (TLR3) agonist Poly I:C or Toll-like receptor 4 (TLR4) agonist LPS. The pre-treated ADSCs were then co-cultured with IL-1β-induced osteoarthritic chondrocytes using a Transwell system to analyze the paracrine effect of ADSCs on reversing the osteoarthritic phenotype of chondrocytes.

RESULTS

RT-PCR and Western blot analysis revealed that Poly I:C and LPS pre-treatments up-regulated the expression of IL-10 and IL-6 in ADSCs, respectively. Furthermore, only Poly I:C-preconditioned ADSCs significantly promoted proliferation while inhibiting apoptosis in IL-1β-treated chondrocytes. Additionally, Poly I:C-preconditioned ADSCs downregulated MMP13 expression while upregulating aggrecan and collagen II expression levels in IL-1β-treated chondrocytes.

CONCLUSIONS

TLR3 activation polarizes ADSCs into an immunomodulatory phenotype distinct from TLR4 activation, exerting differential effects on reversing the osteoarthritic phenotype of chondrocytes; thus indicating that MSCs' paracrine effect regulated by TLRs signaling impacts the efficacy of intra-articular MSCs injection.

Iron overload promotes hemochromatosis-associated osteoarthritis via the mTORC1-p70S6K/4E-BP1 pathway

BACKGROUNDS

Joint iron overload in hemochromatosis induces M1 polarization in synovial macrophages, releasing pro-inflammatory factors and leading to osteoarthritis development. However, the mechanism by which iron overload regulates M1 polarization remains unclear. This study aims to elucidate the mechanism by which synovial iron overload promotes macrophage M1 polarization.

METHODS

In vitro, RAW264.7 macrophages were treated with iron and divided into five groups based on the concentration of the iron chelator, desferrioxamine (DFO): Ctrl, Fe, DFO1, DFO2, and DFO3. In vivo, rats were categorized into five groups based on iron overload and intra-articular DFO injection: A-Ctrl, A-Fe, A-DFO1, A-DFO2, and A-DFO3. Osteoarthritis was induced by transecting the left knee anterior cruciate ligament. Macrophage morphology was observed; Prussian Blue staining quantified iron deposition in macrophages, synovium, and liver; serum iron concentration was measured using the ferrozine method; cartilage damage was assessed using H&E and Safranin O-Fast Green staining; qPCR detected iNOS and Arg-1 expression; Western Blot analyzed the protein expression of iNOS, Arg-1, 4E-BP1, phosphorylated 4E-BP1, p70S6K, and phosphorylated p70S6K; ELISA measured TNF-α and IL-6 concentrations in supernatants; and immunohistochemistry examined the protein expression of F4/80, iNOS, Arg-1, 4E-BP1, phosphorylated 4E-BP1, p70S6K, and phosphorylated p70S6K in the synovium.

RESULTS

In vitro, iron-treated macrophages exhibited Prussian Blue staining indicative of iron overload and morphological changes towards M1 polarization. qPCR and Western Blot revealed increased expression of the M1 polarization markers iNOS and its protein. ELISA showed elevated TNF-α and IL-6 levels in supernatants. In vivo, ferrozine assay indicated significantly increased serum iron concentrations in all groups except A-Ctrl; Prussian Blue staining showed increased liver iron deposition in all groups except A-Ctrl. Iron deposition in rat synovium decreased in a DFO concentration-dependent manner; immunohistochemistry showed a corresponding decrease in iNOS and phosphorylated 4E-BP1 expression, and an increase in Arg-1 expression.

CONCLUSION

Intracellular iron overload may exacerbate joint cartilage damage by promoting synovial macrophage M1 polarization through phosphorylation of 4E-BP1 in the mTORC1-p70S6K/4E-BP1 pathway.

MSRB2 Ameliorates H2O2-induced Chondrocyte Oxidative Stress and Suppresses Apoptosis in Osteoarthritis

BACKGROUND

Chondrocyte oxidative stress and apoptosis are critical factors contributing to the pathogenesis of osteoarthritis (OA). Methionine sulfoxide reductase B2 (MSRB2) is a mitochondrial protein that protects cells from oxidative stress and is involved in apoptosis. This study aimed to investigated the expression of MSRB2 in articular cartilage tissues and elucidated its effect on H2O2-stimulated chondrocytes.

METHODS

Human chondrocytes were cultured in Dulbecco's modified Eagle's medium (DMEM)/F12. MSRB2 overexpression in chondrocytes was achieved by transfecting with an MSRB2 overexpression plasmid. Western blot, quantitative RT-PCR, Immunofluorescence staining, and TUNEL assay were employed in this study.

RESULTS

MSRB2 expression was found to be reduced in OA patients. Furthermore, overexpression of MSRB2 in H2O2-induced chondrocytes mitigated apoptosis and enhanced cell viability. Elevated MSRB2 expression diminished chondrocyte ROS contents, decreased cytochrome C (Cyc) in the cytoplasm, and regulated mitochondrial membrane potential to maintain mitochondrial homeostasis. Interestingly, knockdown of charged multivesicular body protein 5 (CHMP5) led to a decreased inMSRB2 expression in chondrocytes. Additionally, protein levels of CHMP5 and MSRB2 were reduced in H2O2-stimulated chondrocytes, and silencing CHMP5 reduced MSRB2 expression. Knockdown of CHMP5 increased cleaved caspase-3 expression in H2O2-induced chondrocytes and elevated TUNEL-positive chondrocytes.

CONCLUSION

MSRB2 decreased in OA, and overexpression of MSRB2 alleviated oxidative stress and apoptosis of chondrocyte.

Circ_0044235 regulates the development of osteoarthritis by the modulation of miR-375/PIK3R3 axis

BACKGROUND

Circular RNAs (circRNAs) play an important role in osteoarthritis (OA). However, the role of circRNA in OA is still unclear. Here, we explored the role and mechanism of circ_0044235 in OA.

METHODS

CHON-001 cells were treated with IL-1β to establish OA model in vitro. The levels of circ_0044235, miR-375 and phosphoinositide 3-kinase (PI3K) regulatory subunit 3 (PIK3R3) were detected by quantitative real-time PCR. Cell count kit-8 assay and flow cytometry assay were used to detect cell viability and apoptosis. The concentrations of inflammation factors were determined by enzyme-linked immunosorbent assay. Western blot was used to detect protein levels. The interaction between miR-375 and circ_0044235 or PIK3R3 was analyzed by dual-luciferase reporter assay and RNA immunoprecipitation assay.

RESULTS

Circ_0044235 was significantly decreased in OA cartilage tissue and IL-1β-treated CHON-001 cells. Overexpression of circ_0044235 promoted IL-1β-stimulated CHON-001 cell viability and inhibited apoptosis, inflammation, and extracellular matrix (ECM) degradation. In mechanism analysis, circ_0044235 could act as a sponge for miR-375 and positively regulate PIK3R3 expression. In addition, miR-375 ameliorated the effect of circ_0044235 overexpression on IL-1β-mediated CHON-001 cells injury. In addition, miR-375 inhibition mitigated IL-1β-induced CHON-001 cell injury, while PIK3R3 silencing restored the effect.

CONCLUSION

Circ_0044235 knockdown alleviated IL-1β-induced chondrocytes injury by regulating miR-375/PIK3R3 axis, confirming that circ_0044235 might be a potential target for OA treatment.

A Dual Functional Bioinspired Lubricant for Osteoarthritis Treatment and Potential Prevention

Osteoarthritis (OA), primarily characterized by the deterioration of articular cartilage, is a highly prevalent joint-disabling disease. The pathological onset and progression of OA are closely related to cartilage lubrication dysfunction and synovial inflammation. Synergistic options targeted at restorative lubrication and anti-inflammation are expected to be the most attractive candidates to treat OA and perhaps help prevent it. Herein, a bioinspired lubricant (HA/PA@Lipo) was fabricated by combining anionic hyaluronan-graft-poly(2-acrylamide-2-methylpropanesulfonic acid sodium salt) (HA/PA) with cationic liposomes (Lipo) via electrostatic interaction. HA/PA@Lipo mimicked the lubrication complex located on the outer cartilage surface and was endowed cartilage with excellent cartilage-lubricating performances. After the antioxidant gallic acid (GA) was loaded for dual functionality, HA/PA@Lipo-GA was prepared with added anti-inflammatory properties. HA/PA@Lipo-GA showed favorable biocompatibility with C28/I2 cells, inhibited the production of reactive oxygen, and regulated the expression levels of anabolic genes and proteins. The therapeutic effects of HA/PA@Lipo-GA were evaluated using a sodium iodoacetate-induced OA rat model, and the preventive effects of HA/PA@Lipo-GA were estimated in vivo. The results suggested the robust potential of HA/PA@Lipo-GA with dual functions as a candidate option for OA treatment and prevention.

Prevalence of diagnosed and undiagnosed osteoarthrosis and associated factors in the adult general Spanish population

OBJECTIVE

To determine the prevalence and related factors of diagnosed osteoarthrosis (DO) and undiagnosed osteoarthrosis (UO) in the general Spanish adult population.

SETTING

Cross-sectional study with data from the Spanish National Health Survey 2017.

PARTICIPANTS

N=23,089 adults. Three groups of people were defined: DO, UO, and no osteoarthrosis (NO).

MAIN MEASUREMENTS

Sociodemographic information, lifestyle (tobacco, alcohol, physical activity, body mass index) and health factors (intensity of pain, pain drug consumption, mental health, self-perceived health status, pain involvement in daily living) were collected. Descriptive and bivariate analyses were performed, and a multinomial logistic regression model for the factors associated with each group.

RESULTS

The prevalence of DO was 22.4% (95%CI=21.8;22.9) and 0.9% (95%CI=0.8;1) of UO. With respect to NO, risk factors for DO and UO included higher pain levels and pain drug consumption. Better self-perceived health status was inversely related with both. More pain involvement in daily living was associated with increased risk of DO, but reduced risk of UO.

CONCLUSIONS

The prevalence of DO and UO was similar to that reported in Europe, but slightly higher than in low/middle-income countries. It was more prevalent in females, older people, people with worse perceived health status and worse mental health. Higher pain levels and pain drug consumption were risk factors for DO and UO. Better self-perceived health status was protective. Pain involvement in daily living was a risk factor for DO, but protective for UO. Different public health strategies should be considered in view of this.

Overexpression of RAD54L attenuates osteoarthritis by suppressing the HIF-1α/VEGF signaling pathway: Bioinformatics analysis and experimental validation

Osteoarthritis (OA) is a widespread chronic, progressive, degenerative joint disease that causes pain and disability. Current treatments for OA have limited effectiveness and new biomarkers need to be identified. Bioinformatics analysis was conducted to explore differentially expressed genes and DNA repair/recombination protein 54 L (RAD54L) was selected. We firstly overexpressed RAD54L in interleukin-1β (IL-1β)-induced human articular chondrocytes or in OA rats to investigate its effect on OA. Chondrocyte viability and apoptotic rate were measured by Cell Counting Kit-8 and flow cytometry, respectively. Then we evaluated OA severity in vivo by Hematoxylin-eosin staining and Osteoarthritis Research Society International standards. The expression of inflammatory mediators was tested by enzyme-linked immunosorbent assay. Finally, western blot was performed to determine the relative expression level of hypoxia-inducible factors 1α (HIF-1α) and vascular endothelial growth factor (VEGF). Overexpression of RAD54L promoted cell viability and attenuated apoptosis in IL-1β-induced human chondrocytes. A lower Osteoarthritis Research Society International score and a remarkable alleviation of chondrocyte disordering and infiltration of inflammatory cells were found in cartilage tissues of OA rats after overexpressing RAD54L. The inflammatory response induced by OA was decreased by RAD54L overexpression in vitro and in vivo. In addition, RAD54L overexpression decreased the relative expression level of HIF-1α and VEGF. Overexpression of RAD54L could attenuate OA by suppressing the HIF-1α/VEGF signaling pathway, indicating that RAD54L may be a potential treatment target for OA.