Oxidative stress and inflammation in osteoarthritis pathogenesis: Role of polyphenols

Association between ethylene oxide exposure and osteoarthritis risk mediated by oxidative stress: evidence from NHANES 2013-2020

Ethylene oxide is extensively used for sterilizing medical equipment, and its carcinogenicity has been well documented. Furthermore, the onset of multiple diseases, including diabetes and hypertension, has been demonstrated to be associated with exposure to this compound. However, its association with osteoarthritis risk remains elusive. The study analyzed data from the National Health and Nutrition Examination Survey from 2013-2020, which included 6088 American adults, among whom 763 (12.5%) were diagnosed with osteoarthritis. We utilized a weighted generalized linear model to assess the correlation between ethylene oxide exposure levels and osteoarthritis risk. This study used mediation analysis to assess the functions of indicators of oxidative stress (γ-glutamyl transferase) and inflammation (alkaline phosphatase, white blood cell count, neutrophil count, and lymphocyte count) as mediators of how ethylene oxide affects osteoarthritis. The analysis revealed that elevated levels of ethylene oxide were correlated with a higher risk of osteoarthritis, even when controlling for other variables. The odds of developing osteoarthritis were 1.86 times higher in the fourth quartile than in the first quartile (95% confidence interval: 1.20-2.88, P = 0.0097, P for trend = 0.0087). Subgroup analyses indicated consistency across different cohorts. Mediation analysis revealed that oxidative stress (γ-glutamyl transferase), not inflammation, was the mediator linking ethylene oxide levels to the risk of osteoarthritis. This finding in a sample of American adults revealed a direct relationship between exposure to ethylene oxide and increased osteoarthritis risk. Oxidative stress has been suggested as a possible biological explanation for osteoarthritis caused by ethylene oxide.

Review of Metal-Polyphenol Self-Assembled Nanoparticles: Synthesis, Properties, and Biological Applications in Inflammatory Diseases

Polyphenols, which are compounds characterized by the presence of phenolic hydroxyl groups, are abundantly found in natural plants and exist in highly complex forms within living organisms. As some of the most prevalent compounds in nature, polyphenols possess significant medicinal value due to their unique structural features, particularly their therapeutic efficacy in antitumor, anti-inflammatory, and antibacterial applications. In the context of inflammation therapy, polyphenolic compounds can inhibit the excessive release of inflammatory mediators from inflammatory cells, thereby mitigating inflammation. Furthermore, these compounds exhibit strong antioxidant properties, enabling them to scavenge free radicals and reactive oxygen species (ROS), reduce oxidative stress-related damage, and exert anti-inflammatory effects. Due to their multiple phenolic hydroxyl groups and their ability to chelate various metals, polyphenols are extensively utilized in the synthesis of self-assembled nanoparticles for the treatment of various diseases. Numerous studies have demonstrated that the therapeutic profile of nanoparticles formed through self-assembly with metal ions surpasses that of polyphenolic compounds alone. This Review will focus on the self-assembly of different polyphenolic compounds with various metal ions to generate nanoparticles, their characterization, and their therapeutic applications in inflammation-related diseases, providing researchers with new insights into the synthetic study of metal-polyphenol nanocomposites and their biological applications.

Dietary acid load and the odds of knee osteoarthritis: a case-control study

Knee osteoarthritis (KOA) is a common form of arthritis that leads to joint pain and reduced mobility, especially among older adults. Recent studies indicate that dietary acid load (DAL) may play a role in the development of KOA by promoting systemic inflammation. This case-control study aims to investigate the relationship between DAL and KOA in adults aged 40 and older. A total of 150 newly diagnosed cases of KOA and 300 age-, sex-, and BMI-matched controls were recruited from Zabol County, Iran. Dietary intake was assessed using a validated food frequency questionnaire, and DAL was calculated based on nutrient content. Logistic regression was used to estimate the odds of KOA across DAL quartiles, adjusting for confounding factors such as physical activity, smoking, and supplement use. Individuals in the highest quartile of DAL had significantly higher odds of developing KOA compared to those in the lowest quartile (OR: 2.48, 95% CI: 1.36-4.51, p = 0.003), after adjusting for potential confounders. Additionally, the odds of developing KOA was found to increase with increasing quartiles of DAL in both male (OR: 2.52, 95%CI: 1.13 to 5.65, p = 0.024) and female (OR: 2.55, 95%CI: 1.06 to 6.31, p = 0.031) participants, after adjusting for potential confounding variables. This study demonstrates a significant association between high DAL and increased odds of KOA. Reducing DAL through dietary interventions may be a promising strategy for managing KOA, especially in aging populations. Further longitudinal studies are required to confirm these findings and explore causal relationships.

Based exploration of the diagnostic value of oxidative stress-related key genes in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) ranks as the third most common contributor to global mortality. Oxidative stress has been recognized as a critical driver of multiple interacting mechanisms in COPD development. This research investigated the potential of oxidative stress-related genes (OSRGs) biomarkers and their potential molecular mechanisms for COPD clinical diagnosis and treatment through bioinformatics analyses. As a result, 5 hub genes, CA3, PPP1R15B, MAPT, MMP9, and ECT2, were yielded by LASSO, Boruta, and SVM-RFE, and the performance of the nomogram constructed based on hub genes was favorable. Correlation analyses between hub genes and oxidative stress biomarkers showed that MMP9 and MAPT genes had a high association with oxidative stress biomarkers. Immune cell infiltration identified follicular helper T cells, Γδ T cells, M0 macrophages, and CD8 T cells as significantly different in COPD. ROC of ECT2 and MMP9 showed a higher capability to discriminate COPD patients from normal samples. In addition, we collected clinical samples and analyzed the core gene expression, which revealed that the hub genes ECT2 and MMP9 had high discriminatory ability in the COPD samples. The epistasis of ECT2 and MMP9 was further verified by constructing animal models, pathological sections, qPCR, immunoblotting, immunohistochemistry, etc. The data indicated the crucial function of MMP9 in CSC-induced oxidative stress injury. Deprivation of MMP9 attenuated CSC-induced injury and promoted macrophage polarisation to M2 macrophages. MMP9 deprivation protected against CSC-induced injury, mainly related to the reduction of cell apoptosis, cell inflammation, and ROS injury in BEAS-2B. It promoted macrophage polarization from M1 to M2. In summary, we found ECT2 and MMP9 are related to oxidative stress in COPD, and MMP9 was related to cell apoptosis, cell inflammation, and ROS injury in BEAS-2B, and the macrophage polarization from M1 to M2.

Notopterol mitigates osteoarthritis progression and relieves pain in mice by inhibiting PI3K/Akt/GPX4-mediated ferroptosis

Ferroptosis-induced lipid peroxidation in chondrocytes exacerbates intra-articular inflammation, oxidative stress, and articular cartilage degradation, accelerating osteoarthritis (OA) progression. Effective anti-inflammatory and antioxidant interventions can alleviate both joint pain and cartilage damage. This study aims to elucidate the therapeutic effects of Notopterol (NP), a bioactive compound extracted from the rhizome of Notopterygium incisum, a traditional Chinese medicine known for its potent anti-inflammatory and antioxidant properties, in treating OA. An in vivo mouse model of OA was established through medial meniscus destabilization (DMM). Intra-articular injections of NP over a 4-week treatment period significantly alleviated pain and gait abnormalities, reduced subchondral osteosclerosis, and attenuated cartilage degradation compared to the untreated DMM group. In vitro, chondrocytes treated with IL-1β to simulate OA conditions exhibited increased viability following NP pretreatment, with concurrent reductions in apoptosis, reactive oxygen species (ROS) accumulation, and chondrocyte catabolic dysfunction, along with enhanced extracellular matrix (ECM) synthesis. Mechanistically, NP exerts its anti-OA effects by inhibiting PI3K/Akt phosphorylation, suppressing ferroptosis, and improving antioxidant defense via upregulation of glutathione (GSH) and glutathione peroxidase 4 (GPX4), thereby preventing lipid peroxidation. In conclusion, NP modulates the PI3K/Akt/GPX4 axis to protect against lipid peroxidation, inhibit ferroptosis, and preserve cartilage integrity, thus delaying OA progression.

Suppressive effect of curcumin on apoptosis of articular chondrocytes via regulation on NF-κB pathway and NLRP3 inflammasome

Our study probed into how curcumin modulates NF-κB pathway to regulate articular chondrocytes. ATDC5 cells were exposed to varying concentrations of curcumin (0, 10, 20, 50, or 100 μM) for 48 h, followed by an assessment of curcumin's cytotoxicity. Cells were also treated with 10 ng/ml IL-1β, curcumin, 5 μg/L NF-κB inhibitor (PDTC), and 5 μM NLRP3 inflammasome inducer (nigericin) for 48 h, before cell viability, apoptosis, NF-κB pathway-related proteins, NLRP3 inflammasome-related proteins and inflammatory cytokines were detected. IL-1β treatment notably diminished chondrocyte viability and increased apoptosis, evidenced by elevated level of Bax and cleaved caspase-3, and reduced level of Bcl2, while such expression patterns were reversed by curcumin treatment in a concentration-dependent fashion. Additionally, NF-κB pathway and NLRP3 inflammasome in chondrocytes were activated by IL-1β treatment, but can also be suppressed following curcumin intervention. Furthermore, inhibition of NF-κB pathway curtailed the NLRP3 inflammasome activation and chondrocyte apoptosis, while activation of the NLRP3 inflammasome partially reversed the protective impacts of curcumin against chondrocyte apoptosis. Curcumin inhibits NF-κB pathway, thereby preventing the NLRP3 inflammasome activation and ameliorating IL-1β-induced apoptosis in articular chondrocytes.

Intelligent Nanomaterials Design for Osteoarthritis Managements

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

Differential Responses of Articular Chondrocytes from Diabetic and Non-Diabetic Rats to Glucose Conditions and Inflammatory Stimuli: Influence of a Vitamin K2 Enriched Diet

ObjectiveMeanwhile, the association between osteoarthritis (OA) and type 2 diabetes mellitus (T2DM) is well known. However, it remains unclear whether vitamin K2 (vit.K2) could exert chondroprotective effects. Hence, this study investigates the interrelation between OA and T2DM under the influence of vit.K2 in chondrocytes.MethodsUsing an in vitro OA/T2DM model, articular chondrocytes were harvested from adult male Zucker diabetic fatty (ZDF) Leptfa/Crl rats, categorized as non-diabetic (heterozygous: fa/+) or diabetic (homozygous: fa/fa). Based on vit.K2 supplementation of the rats, four groups arose: control without or with vit.K2 and diabetic without or with vit.K2 supplementation. Inflammatory conditions simulating OA were induced by exposing chondrocytes to tumor necrosis factor alpha (TNFα) and C5a. Chondrocyte response was analyzed using proliferation, metabolic and wound healing assays, immunolabeling, as well as gene expression analyses.ResultsThe proliferation of chondrocytes from control rats with vit.K2 supplementation was significantly higher than those without vit.K2 feeding, under both normoglycemic (NG) and hyperglycemic (HG) conditions. The wound closure ability of chondrocytes was significantly higher in the non-diabetic compared with the diabetic chondrocyte donor group. TNFα and C5a exerted catabolic effects under HG conditions by significantly inducing Tnfα gene activity in chondrocytes of control rats without vit.K2 supplementation and a significant reduction of collagen type 2 gene expression in those cells of control rats with vit.K2 supplementation.ConclusionsThe response of chondrocytes derived from non-diabetic and diabetic donors differed. The vit.K2 supply of chondrocyte donor rats exerted anabolic effects on chondrocytes.

Gel@CAT-L hydrogel mediates mitochondrial unfolded protein response to regulate reactive oxygen species and mitochondrial homeostasis in osteoarthritis

OBJECTIVE

This study investigates the role of Gelatin-Catalase (Gel@CAT)-L hydrogel in mediating reactive oxygen species (ROS) production and maintaining mitochondrial homeostasis through SIRT3-mediated unfolded protein response (UPRmt), while exploring its involvement in the molecular mechanism of osteoarthritis (OA).

METHODS

Self-assembled Gel@CAT-L hydrogels were fabricated and characterized using transmission electron microscopy, mechanical testing, external release property evaluation, and oxygen production measurement. Biocompatibility was assessed via live/dead cell staining and CCK8 assays. An OA mouse model was established using destabilization of the medial meniscus (DMM) surgery. X-ray and micro-CT imaging were employed to evaluate the structural integrity of the mouse knee joints, while histological staining was used to assess cartilage degeneration. Immunohistochemistry was performed to analyze the expression of proteins including Col2a1, Aggrecan, MMP13, ADAMTS5, SIRT3, PINK1, and Parkin. Multi-omics analyses-encompassing high-throughput sequencing, proteomics, and metabolomics-were conducted to identify key genes and metabolic pathways targeted by Gel@CAT-L hydrogel intervention in OA. Immunofluorescence techniques were utilized to measure ROS levels, mitochondrial membrane potential, and the expression of SIRT3, PINK1, Parkin, LYSO, LC3B, Col2a1, and MMP13 in primary mouse chondrocytes and mouse knee joints. Flow cytometry was applied to quantify ROS-positive cells. RT-qPCR analysis was conducted to determine mRNA levels of Aggrecan, Col2a1, ADAMTS5, MMP13, SIRT3, mtDNA, HSP60, LONP1, CLPP, and Atf5 in primary mouse chondrocytes, mouse knee joints, and human knee joints. Western blotting was performed to measure protein expression levels of SIRT3, HSP60, LONP1, CLPP, and Atf5 in both primary mouse chondrocytes and mouse knee joints. Additionally, 20 samples each from the control (CON) and OA groups were collected for analysis. Hematoxylin and eosin staining was used to evaluate cartilage degeneration in human knee joints. The Mankin histological scoring system quantified the degree of cartilage degradation, while immunofluorescence analyzed SIRT3 protein expression in human knee joints.

RESULTS

In vitro experiments demonstrated that self-assembled Gel@CAT-L hydrogels exhibited excellent biodegradability and oxygen-releasing capabilities, providing a stable three-dimensional environment conducive to cell viability and proliferation while reducing ROS levels. Multi-omics analysis identified SIRT3 as a key regulatory gene in mitigating OA and revealed its central role in the UPRmt pathway. Furthermore, Gel@CAT-L was confirmed to regulate mitochondrial homeostasis. Both in vitro experiments and in vivo mouse model studies confirmed that Gel@CAT-L significantly reduced ROS levels and regulated mitochondrial autophagy by activating the SIRT3-mediated UPRmt pathway, thereby improving the pathological state of OA. Clinical trials indicated downregulation of SIRT3 and UPRmt-related proteins in OA patients.

CONCLUSION

Gel@CAT-L hydrogel activates SIRT3-mediated UPRmt to regulate ROS and mitochondrial homeostasis, providing potential therapeutic benefits for OA.

Sodium alginate microspheres loaded with Quercetin/Mg nanoparticles as novel drug delivery systems for osteoarthritis therapy

BACKGROUND

Osteoarthritis (OA) is the most prevalent arthritic disease characterized by cartilage degradation and low-grade inflammation, for which there remains a lack of efficacious therapeutic interventions. Notably, mitigating the impact of oxidative stress (OS) and inflammatory factors could help alleviate or hinder the advancement of OA. Given the benefits of both quercetin (Que) and Magnesium ion (Mg2+) in OA treatment, coupled with the structural properties of Que, we have innovatively developed the Que-Mg2+ nanoparticles (NPs), aiming to deliver both Que and Mg2+ simultaneously and achieve enhanced therapeutic outcomes for OA. Moreover, to avoid the adverse reactions linked to frequent injections, sodium alginate (SA) microspheres encapsulating Que-Mg2+ NPs (Que-Mg@SA) were designed to treat the H2O2-induced OA cell model.

METHODS

Que-Mg@SA microspheres were synthesized using the ionotropic gelation technique, with calcium chloride acting as the cross-linking agent. Comprehensive characterization of the Que-Mg@SA was conducted through transmission electron microscope (TEM), dynamic light scattering (DLS), optical microscope, and scanning electron microscope (SEM), which provided detailed insights into their size, zeta potential, morphology, and micromorphology. Additionally, the microsphere swelling rate and Que release were evaluated. The biocompatibility of Que-Mg@SA microspheres, along with their impact on chondrocyte viability, were detected through CCK-8 assay and live/dead cell staining. Furthermore, the antioxidant and anti-inflammatory properties of Que-Mg@SA were evaluated by examining the ROS scavenging ability and pro-inflammatory factors levels, respectively. Finally, the regulatory influence of Que-Mg@SA microspheres on extracellular matrix (ECM) metabolism in OA was assessed by immunofluorescence staining and Western blot.

RESULTS

Characterization results revealed that Que-Mg NPs exhibit nanoscale diameter, exceptional stability, and good dispersibility, while Que-Mg@SA possesses high entrapment efficiency (EE%) and loading efficiency (LE%), pronounced hygroscopic properties, and sustained drug-release capabilities. Additionally, in vitro cellular assays revealed that the biocompatible Que-Mg@SA microspheres significantly restored chondrocyte viability, scavenged H2O2-induced excessive ROS, reduced the levels of inflammatory cytokines, upregulated cartilage anabolic gene expression, downregulated cartilage catabolic protease gene expression, and maintained the metabolic balance of cartilage tissue.

CONCLUSION

The functionalized Que-Mg@SA microspheres developed in our study hold great promise as a drug delivery system for OA and potentially other biomedical applications.

CLINICAL TRIAL NUMBER

Not applicable.

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

Background

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

Methods

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

Results

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

Conclusion

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

Perspectives of exosomal ncRNAs in the treatment of bone metabolic diseases: Focusing on osteoporosis, osteoarthritis, and rheumatoid arthritis

Bone metabolic disorders, constituting a group of prevalent and grave conditions, currently have a scarcity of therapeutic alternatives. Over the recent past, exosomes have been at the forefront of research interest, owing to their nanoparticulate nature and potential for therapeutic intervention. ncRNAs are a class of heterogeneous transcripts that they lack protein-encoding capacity, yet they can modulate the expression of other genes through multiple mechanisms. Mounting evidence underscores the intricate role of exosomes as ncRNAs couriers implicated in the pathogenesis of bone metabolic disorders. In this review, we endeavor to elucidate recent insights into the roles of three ncRNAs - miRNAs, lncRNAs, and circRNAs - in bone metabolic ailments such as osteoporosis, osteoarthritis, and rheumatoid arthritis. Additionally, we examine the viability of exosomal ncRNAs as innovative, cell-free modalities in the diagnosis and therapeutic management of bone metabolic disorders. We aim to uncover the critical function of exosomal ncRNAs within the context of bone metabolic diseases.

ROS fueled autonomous sol-gel-sol transitions for on-demand modulation of inflammation in osteoarthritis

Osteoarthritis is the most prevalent form of arthritis, and a leading cause of pain and long-term disability. Dysregulation of redox homeostasis is a key feature in the pathological progression of osteoarthritis that amplifies the inflammatory response, aggravates synovitis and accelerates cartilage degradation. Herein, a hemin and chitosan-mediated antioxidant gel inducing ROS conversion (hc-MAGIC) was constructed to targeting oxidative stress for osteoarthritis treatment. The optimized hc-MAGIC exhibited autonomous sol-gel-sol transition properties, which enable to be administered via intra-articular injections, prolong retention in the joint cavity, and controlled modulation of inflammation in response to ROS. Notably, with extracellular ROS fueled, hc-MAGIC could address hypoxia in the osteoarthritic joint cavity through spatiotemporally controlled generation of oxygen (O2). Moreover, hc-MAGIC restored the impaired antioxidative capacity of macrophages by upregulating HO-1 on demand, resulting in suppressing excessive intracellular ROS generation. Consequently, by restoring both extracellular and intracellular redox homeostasis in osteoarthritic joints, hc-MAGIC markedly reversed the inflammatory microenvironment to support chondrogenesis, prevented cartilage degradation, and promoted cartilage repair by augmenting cartilage matrix formation. Therefore, featuring its sol-gel-sol transition properties，ROS-to-O2 conversion, and dual-mode redox regulation, hc-MAGIC offers a potent novel therapy for on-demand modulation of inflammation in osteoarthritis.

Knowledge map and emerging trends of oxidative stress in wound healing: A bibliometric analysis from 2000 to 2023

The skin's integrity is vulnerable to external elements that can induce injuries, leading to wound formation. It's crucial to comprehend wound healing processes to protect the body when this protective barrier is compromised. Over the last 2 decades, there has been considerable progress in understanding delayed wound healing, with a focus on the mechanisms and microenvironmental factors involved. The connection between oxidative stress and wound healing has recently gained attention, emphasizing the need for in-depth analysis to propel further advancements and interventions in this area. Despite these advancements, there remains a noticeable void in the literature concerning the application of scientometric methods to systematically examine the progression of wound healing research. Additionally, a comprehensive assessment of the research output and effectiveness of various researchers and institutions in this field is lacking. To address these gaps, we analyzed data from the Web of Science Core Collection from January 1, 2000, to December 31, 2023, utilizing relevant keywords. Using CiteSpace, we created visual maps that depict the evolution and structure of keyword clusters, and both CiteSpace and VOSviewer were used to evaluate the performance of research networks across different countries, institutions, and authors. This data was methodically analyzed. The leading institution in this field is the Chinese Academy of Medical Sciences. The key researchers are Bekeschus, Sander; Li, Yang; Bi, Yang; Fan, Daidi; and Zhang, Yu. Our software analysis reviewed 3025 studies, revealing 19 co-citation clusters that highlight current trends in research on oxidative stress and wound healing. Prominent journals, leading institutions, and key researchers were identified. Key emerging research directions include studying the mechanisms linking oxidative stress to wound healing, exploring the use of antioxidant substances in wound dressings, and investigating how nanomaterials in dressings can influence oxidative stress. These focal points emphasize the significance of understanding oxidative stress's impact on wound healing and investigating new methods to enhance therapeutic efficacy. This comprehensive approach not only fills a gap in the current literature but also sets the stage for future research endeavors in this crucial area of health science.

Targeted activation on Bnip3 enhances mitophagy to prevent the progression of osteoarthritis

Background

The production of reactive oxygen species (ROS) and mitochondrial dysfunction in chondrocytes are closely related to cartilage degeneration in the procedure of osteoarthritis (OA). Mitophagy is responsible for the scavenging of ROS and dysfunctional mitochondria and is considered a key therapeutic target for the treatment of OA. Tiopronin, a classic thiol antioxidant, has been widely studied for the treatment of various oxidative stress-related diseases.

Methods

The expression of mitophagy (PINK1, PARKIN, and TOMM20) in intact and damaged cartilage of OA patients was analyzed by Western blot and histological analysis. RNA sequencing (RNA-seq) analysis was performed to explore the molecular mechanism of tiopronin in regulating mitophagy in chondrocytes, and then to find the specific target of tiopronin. The therapeutic effects of tiopronin were evaluated in the OA model induced by destabilisation of the medial meniscus (DMM), chondrocytes degenerative model with the primary chondrocytes from mouse and human cartilage explants experiment. The downstream molecular mechanisms of tiopronin were further investigated by si-RNA knockdown of mitophagy-related proteins.

Results

The level of mitophagy in cartilage was negatively correlated with the severity of OA. We revealed that tiopronin promoted the anabolism of the extracellular matrix (ECM) of hyaline chondrocytes and alleviates ROS in vitro and in vivo by strengthening mitophagy. Moreover, tiopronin strongly activated the expression of Bnip3, a protein anchored in the mitochondrial membrane, and subsequently enhanced the Pink1/Parkin signaling pathway.

Conclusion

These findings indicate that the Bnip3-Pink1-Parkin signaling pathway, targeted and activated by tiopronin, plays a key role in inhibiting the progression of OA.

The translational potential of this article

As a classical drug in clinic, tiopronin was developed a new therapeutic approach in the treatment in OA via this study. Based the significant and efficient effect of tiopronin in inhibiting the cartilage degermation and delay the progression of OA, it was believed that tiopronin may become an effective therapeutic candidate for OA treatment in clinical settings.

Ferroptosis in Osteoarthritis: Towards Novel Therapeutic Strategy

Osteoarthritis (OA) is a chronic, degenerative joint disease primarily characterised by damage to the articular cartilage, synovitis and persistent pain, and has become one of the most common diseases worldwide. In OA cartilage, various forms of cell death have been identified, including apoptosis, necroptosis and autophagic cell death. Ever-growing observations indicate that ferroptosis, a newly-discovered iron-dependent form of regulated cell death, is detrimental to OA occurrence and progression. In this review, we first analyse the pathogenetic mechanisms of OA by which iron overload, inflammatory response and mechanical stress contribute to ferroptosis. We then discuss how ferroptosis exacerbates OA progression, focusing on its impact on chondrocyte viability, synoviocyte populations and extracellular matrix integrity. Finally, we highlight several potential therapeutic strategies targeting ferroptosis that could be explored for the treatment of OA.

BCL6 Promotes Transcription of GPR61 to Suppress IL-1β-Induced Osteoarthritis Progression in C28/I2 Cells

Osteoarthritis (OA) is the most common joint disease and its pathogenic mechanism remains to be ensured. This study focused on the regulatory relation between B-cell lymphoma 6 (BCL6) and G-protein-coupled receptor 61 (GPR61) underlying IL-1β in OA. Real-time quantitative polymerase chain reaction and western blot were performed for mRNA and protein detection. Oxidative injury was assessed by reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH) via kits. Fe2+ level was measured via an iron assay kit. Relation analysis between BCL6 and GPR61 was implemented employing ChIP assay and dual-luciferase reporter assay. GPR61 was downregulated in OA samples and IL-1β-induced C28/I2 cells. IL-1β-induced cell inflammation, extracellular matrix (ECM) degradation, oxidative stress, and ferroptosis were all returned by overexpression of GPR61. BCL6 downregulation was detected in OA patients and IL-1β-exposed C28/I2 cells. BCL6 could promote the transcription of GPR61. BCL6 suppressed IL-1β-induced OA progression by upregulating GPR61. The BCL6/GPR61 axis activated the PKA/CREB pathway in IL-1β-treated C28/I2 cells. The above results suggested that BCL6 mitigated OA progression induced by IL-1β by enhancing transcription of GPR61. BCL6/GPR61/PKA/CREB axis may be considered as a novel regulatory mechanism in OA, and BCL6 has the potential to act as a novel target for OA.

Isolation, Characterization, and In Vitro Cell Studies of Plant-Based Exosome-like Nanovesicles for Treatment of Early Osteoarthritis

Osteoarthritis, affecting over 8 million people in the UK, remains a debilitating condition with limited treatment options. Current therapies primarily address symptoms and can exacerbate joint damage over time. Developing disease-modifying drugs that alleviate inflammation and promote joint regeneration is crucial for long-term patient benefit. This study investigates the potential of exosome-like nano-vesicles isolated from grapefruit juice (GEVs) as a novel therapeutic approach for osteoarthritis. GEVs possess regenerative properties and present a promising avenue for clinical translation. In this study, nano-vesicles were isolated and characterized in terms of protein quantification, size, and morphology. In vitro studies demonstrated the safety and efficacy of GEVs, showing an enhancement in human chondrocyte migratory activity of over 13%. GEVs exhibited a dual mechanism of action, reducing inflammation and oxidative stress while promoting cellular regeneration. Specifically, they reduced the expression of COX2 and PTGS2, markers associated with inflammation and pain sensitization, and enhanced the expression of antioxidant genes SD2 and GPX in osteoarthritic-like chondrocytes. Additionally, GEVs downregulated the expression of ADAMTS-5 and hypertrophic COL10 while upregulating chondrogenic markers ACAN, COL2, and SOX9. This research signifies a significant advancement in osteoarthritis therapy, offering a natural, safe, and cost-effective treatment option with the potential for long-lasting benefits. Clinical translation of GEV therapy holds promise for improving patient outcomes and reducing the burden on healthcare systems.

Potential Chondroprotective Effect of Artemisia annua L. Water Extract on SW1353 Cell

Inflammation plays a critical role in the pathogenesis of osteoarthritis (OA). The objective of this study was to investigate the anti-inflammatory and chondroprotective properties of Artemisia annua L. water extract (AWE) following the induction of inflammation in cartilage cells (SW1353 cell) through the administration of interleukin-1 beta (IL-1β). We demonstrated significant antioxidant activity, as evidenced by elevated total phenolic and flavonoid content, in addition to robust free radical scavenging capacity, as assessed through DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays. Its cytotoxic effects were assessed at a concentration of 200 μg/mL, where no cytotoxic signs were observed in SW1353 cells treated with IL-1β; the levels of reactive oxygen species (ROS) were notably reduced in a dose-dependent manner. The principal inflammatory markers, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), were significantly diminished by AWE treatment. AWE administration led to a dose-dependent reduction in the expression of key proteins involved in the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) signaling pathways, ultimately resulting in a decrease in the release of matrix metalloproteinases (MMPs), specifically MMP-1 and MMP-13, which are known to contribute to cartilage degradation. Additionally, the levels of degraded collagen type II in the cartilage cells were restored. These findings suggest that reducing oxidative stress and inflammation, along with inhibiting activated MAPK and NF-κB signaling pathways, may ameliorate the progression of IL-1β-induced OA. Furthermore, a molecular docking analysis revealed a strong binding affinity of MMP-13, a critical mediator in the pathogenesis of OA. Six compounds were identified in AWE, corroborating its potential antioxidant and anti-inflammatory effects. Therefore, AWE may serve as a potentially useful therapeutic agent against OA by modulating inflammation-related mechanisms.

Anthocyanins and Anthocyanidins in the Management of Osteoarthritis: A Scoping Review of Current Evidence

Background/Objectives: The consumption of food rich in anthocyanins, a natural pigment found in plants, has been associated with improved joint health. However, systematic efforts to summarise the effects of anthocyanins and their deglycosylated forms, anthocyanidins, in managing osteoarthritis (OA) are lacking. This scoping review aims to comprehensively summarise the current evidence regarding the role of anthocyanins and anthocyanidins in OA management and highlights potential research areas. Methods: A comprehensive literature search was performed using PubMed, Scopus, and Web of Science in January 2025 to look for primary studies published in English, with the main objective of investigating the chondroprotective effects of anthocyanins and anthocyanidins, regardless of their study designs. Results: The seven included studies showed that anthocyanins and anthocyanidins suppressed the activation of inflammatory signalling, upregulated sirtuin-6 (cyanidin only), and autophagy (delphinidin only) in chondrocytes challenged with various stimuli (interleukin-1β, oxidative stress, or advanced glycation products). Anthocyanins also preserved cartilage integrity and increased the pain threshold in animal models of OA. No clinical trial was found in this field, suggesting a translation gap. Conclusions: In conclusion, anthocyanins and anthocyanidins are potential chondroprotective agents, but more investigations are required to overcome the gap in clinical translation.

Recent applications of stimulus-responsive smart hydrogels for osteoarthritis therapy

Osteoarthritis is one of the most common degenerative joint diseases, which seriously affects the life of middle-aged and elderly people. Traditional treatments such as surgical treatment and systemic medication, often do not achieve the expected or optimal results, which leads to severe trauma and a variety of side effects. Therefore, there is an urgent need to develop novel therapeutic options to overcome these problems. Hydrogels are widely used in biomedical tissue repairing as a platform for loading drugs, proteins and stem cells. In recent years, smart-responsive hydrogels have achieved excellent results as novel drug delivery systems in the treatment of osteoarthritis. This review focuses on the recent advances of endogenous stimuli (including enzymes, pH, reactive oxygen species and temperature, etc.) responsive hydrogels and exogenous stimuli (including light, shear, ultrasound and magnetism, etc.) responsive hydrogels in osteoarthritis treatment. Finally, the current limitations of application and future prospects of smart responsive hydrogels are summarized.

Recent development of mitochondrial metabolism and dysfunction in osteoarthritis

Osteoarthritis is a degenerative joint disorder characterized by cartilage degradation, synovial inflammation, and altered subchondral bone structure. Recent insights have identified mitochondrial dysfunction as a pivotal factor in OA pathogenesis, contributing to chondrocyte apoptosis, oxidative stress, and extracellular matrix degradation. Disruptions in mitochondrial dynamics, including impaired biogenesis, mitophagy, and metabolic shifts from oxidative phosphorylation to glycolysis, exacerbate cartilage damage by promoting the production of reactive oxygen species and matrix-degrading enzymes such as ADAMTS and MMPs. This review explores the molecular mechanisms underlying mitochondrial dysfunction in OA, emphasizing its role in cartilage homeostasis and inflammation. Furthermore, it highlights emerging therapeutic strategies targeting mitochondrial pathways, including antioxidants, mitophagy enhancers, and metabolic modulators, as potential interventions to mitigate disease progression, which offer promising avenues for advancing personalized and disease-modifying treatments in OA.

Senile Osteoarthritis Regulated by the Gut Microbiota: From Mechanisms to Treatments

Osteoarthritis (OA) is a chronic, progressive degenerative joint disease that affects the entire synovial joint, leading to the progressive degeneration of articular cartilage. It seriously affects the quality of life and global disability of patients. OA is affected by a variety of factors; the most significant risk factor for OA is age. As individuals age, the risk and severity of OA increase due to the exacerbation of cartilage degeneration and wear and tear. In recent years, research has indicated that the gut microbiota may play a significant role in the aging and OA processes. It is anticipated that regulating the gut microbiota may offer novel approaches to the treatment of OA. The objective of this paper is to examine the relationship between the gut microbiota and senile OA, to investigate the potential mechanisms involved. This review also summarizes the therapeutic strategies related to gut flora in OA management, such as prebiotics and probiotics, diet, exercise, traditional Chinese medicine (TCM) modification, and fecal microbiota transplantation (FMT), highlighting the potential clinical value of gut flora and elucidating the current challenges. The foundation for future research directions is established through the summarization of current research progress.

Progress in multi-omics studies of osteoarthritis

Osteoarthritis (OA), a ubiquitous degenerative joint disorder, is marked by pain and disability, profoundly impacting patients' quality of life. As the population ages, the global prevalence of OA is escalating. Omics technologies have become instrumental in investigating complex diseases like OA, offering comprehensive insights into its pathogenesis and progression by uncovering disease-specific alterations across genomics, transcriptomics, proteomics, and metabolomics levels. In this review, we systematically analyzed and summarized the application and recent achievements of omics technologies in OA research by scouring relevant literature in databases such as PubMed. These studies have shed light on new potential therapeutic targets and biomarkers, charting fresh avenues for OA diagnosis and treatment. Furthermore, in our discussion, we highlighted the immense potential of spatial omics technologies in unraveling the molecular mechanisms of OA and in the development of novel therapeutic strategies, proposing future research directions and challenges. Collectively, this study encapsulates the pivotal advances in current OA research and prospects for future investigation, providing invaluable references for a deeper understanding and treatment of OA. This review aims to synthesize the recent progress of omics technologies in the realm of OA, aspiring to furnish theoretical foundations and research orientations for more profound studies of OA in the future.

Chondrocyte-targeted bilirubin/rapamycin carrier-free nanoparticles alleviate oxidative stress and modulate autophagy for osteoarthritis therapy

Osteoarthritis (OA) is a prevalent chronic disease, characterized by the destruction of joint cartilage and synovitis, affects over 7 % of people worldwide. Disease-modifying treatments for OA still face significant challenges. Chondrocytes, as the exclusive cellular component of articular cartilage, play a pivotal role in synthesizing the intricate matrix of cartilage, thereby assuming a critical responsibility in facilitating its renewal and repair processes. However, oxidative stress within chondrocytes and subsequent apoptotic cell death plays significant roles in the progression of OA. Therefore, targeting apoptosis inhibition and mitigation of oxidative stress in chondrocytes represents a promising therapeutic strategy for OA. This study develops a type II collagen-targeting peptide (WYRGRLC) modified bilirubin/rapamycin carrier-free nanoparticle (PP/BRRP) and evaluate its therapeutic potential for OA. The PP/BRRP system exhibits remarkable chondrocyte-targeting ability, enabling the rupture of highly oxidized chondrocytes and subsequent release of bilirubin and rapamycin. This dual payload effectively scavenges reactive oxygen species, triggers autophagy, and suppresses the mTOR pathway, thereby augmenting anti-inflammatory and anti-apoptotic effects. The in vivo experiments further validate the retention and therapeutic efficacy of PP/BRRP in rat joints affected by OA. Overall, PP/BRRP exhibits significant potential for intervention and treatment of OA.

Ginkgetin delays the progression of osteoarthritis by inhibiting the NF-κB and MAPK signaling pathways

BACKGROUND

Osteoarthritis (OA) is considered an advancing chronic degenerative joint disease, leading to severe physical functional impairment of patients. Its development is closely related to increased inflammation and oxidative stress within the joint. Ginkgetin (GK), a natural non-toxic chemical, has proven anti-inflammatory, antioxidant, anti-tumor, and neuroprotective effects.

METHODS

First, this study utilizes network pharmacology to explore the intrinsic connection between GK and OA. In vitro, SW1353 human cartilage cells were stimulated with Tert-butyl hydrogen peroxide (TBHP), and different GK concentrations were pre-treated to evaluate its protective effects. GK's anti-inflammatory and antioxidative effects were comprehensively assessed via MTT assay, western blot, cell immunofluorescence, ELISA, and transcriptome sequencing. Potential underlying mechanisms were also explored. In vivo, OA was induced in rats via anterior cruciate ligament transection (ACLT), and GK's impact on cartilage protection was further assessed via histological analysis and western blot.

RESULTS

Network pharmacology has revealed that GK regulates OA via several key pathways, especially NF-κB, HIF-1, PI3K-AKT, and substances like reactive oxygen species. In vitro experiments showed GK effectively reverses oxidative stress damage from TBHP, inhibits inflammatory factor release, and protects Extracellular matrix (ECM) from degradation. These functions may be achieved via the NF-κB and MAPK signaling pathways. In vivo experiments showed GK significantly reduced proteoglycan loss from ACLT and inhibited matrix metalloproteinase 13 (MMP13) and ADAMTS5 (A disintegrin and metalloproteinase with thrombospondin motifs 5) production, effectively preventing cartilage degeneration in rats.

CONCLUSION

These findings suggest that GK has potential as a therapeutic agent for OA, offering new strategies and directions for OA treatment.

Remodeling the Proinflammatory Microenvironment in Osteoarthritis through Interleukin-1 Beta Tailored Exosome Cargo for Inflammatory Regulation and Cartilage Regeneration

Osteoarthritis (OA) presents a significant therapeutic challenge, with few options for preserving joint cartilage and repairing associated tissue damage. Inflammation is a pivotal factor in OA-induced cartilage deterioration and synovial inflammation. Recently, exosomes derived from human umbilical cord mesenchymal stem cells (HucMSCs) have gained recognition as a promising noncellular therapeutic modality, but their use is hindered by the challenge of harvesting a sufficient number of exosomes with effective therapeutic efficacy. Given that HucMSCs are highly sensitive to microenvironmental signals, we hypothesized that priming HucMSCs within a proinflammatory environment would increase the number of exosomes secreted with enhanced anti-inflammatory properties. Subsequent miRNA profiling and pathway analysis confirmed that interleukin-1 beta (IL-1β)-induced exosomes (C-Exos) exert positive effects through miRNA regulation and signaling pathway modulation. In vitro experiments revealed that C-Exos enhance chondrocyte functionality and cartilage matrix production, as well as macrophage polarization, thereby enhancing cartilage repair. C-Exos were encapsulated in hyaluronic acid hydrogel microspheres (HMs) to ensure sustained release, leading to substantial improvements in the inflammatory microenvironment and cartilage regeneration in a rat OA model. This study outlines a strategy to tailor exosome cargo for anti-inflammatory and cartilage regenerative purposes, with the functionalized HMs demonstrating potential for OA treatment.

Harnessing Theraoenergetics for Cartilage Regeneration: Development of a Therapeutic and Bioenergetic Loaded Janus Nanofiber Reinforced Hydrogel Composite for Cartilage Regeneration

Advancements in tissue engineering and regenerative medicine have highlighted different strategies of engineering and designing hydrogels to replicate the intricate structure of cartilage extracellular matrix (ECM) for effective cartilage regeneration. However, despite efforts to meet the elevated structural and mechanical demands of cartilage repair, researchers often overlook the challenging environmental conditions at damaged cartilage sites such as inflammation, hypoxia, and the limited availability of nutrients and energy, which are critical for supporting tissue regeneration. The insufficient oxygen, nutrient availability, and oxidative stress in avascular cartilage limit the oxidative phosphorylation-mediated bioenergetics in cells needed for energy demands required for anabolic biosynthesis, cell division, and migration during tissue repair. Thus, there is a need to develop an advanced approach to engineer a unique hydrogel system that not only provides intricate structural properties but also integrates therapeutics (like anti-inflammatory, reactive oxygen species (ROS) scavenging) and bioenergetics (like oxygen, energy demand) into the hydrogel, which may offer a holistic and effective solution for repairing cartilage defects under a harsh microenvironment. In this study, we engineered an innovative approach to develop a new class of theraoenergetic hydrogel system by reinforcing a Janus nanofiber (JNF) carrying therapeutic (MgO) and bioenergetic (polyglutamic acid), PGA) components into a dual network photo-crosslinkable hydrogel. Reinforcement of JNF microfragments and the photo-crosslinking dual network of synthesized gelatin methacryloyl (GelMA) and carboxymethyl chitosan (CMCh) not only enhances the hydrogel's mechanical properties by 800% to withstand mechanical load but also ensures a controlled release of magnesium, oxygen, and PGA over 30 days. Co-delivery of magnesium and bioenergetic PGA with oxygen helped synergistically to reduce intracellular ROS and inflammatory markers IL-6 and TNF-α, providing a supportive environment for enhancing cell mitochondrial oxidative metabolism leading to active proliferation and chondrogenic differentiation of stem cells to deposit glycosaminoglycan (GAG)-rich extracellular matrix to regenerate cartilage. The developed theraoenergetic hydrogel system represents a promising solution for regenerating cartilage under a harsh microenvironment to treat osteoarthritis, a rising global health burden.

Treatment with a superoxide dismutase mimetic for joint preservation during 35 and 75 days in orbit aboard the international space station, and after 120 days recovery on Earth

Reduced weight-bearing during spaceflight has been associated with musculoskeletal degradation that risks astronaut health and performance in transit and upon reaching deep space destinations. Previous rodent experiments aboard the international space station (ISS) have identified that the spaceflight-induced molecular arthritic phenotype was characterized with an increase in oxidative stress. This study evaluated if treatment with a superoxide dismutase (SOD) mimetic on orbit could prevent spaceflight-induced damage to the knee and hip articular cartilage, and the menisci in rodents. Cartilage and meniscal degradation in mice were measured via microCT, histology, and transcriptomics after: (1) ∼ 35 days on the ISS, (2) ∼ 35 days on the ISS followed by 120 days weight-bearing readaptation on Earth or (3) ∼ 75 days on the ISS. The study had a limited sample size, so both significant effects and generalized patterns are reported. After 35 days aboard the ISS, cartilage volume at the tibial-femoral cartilage-cartilage contact point decreased, meniscal volume decreased concurrent with an increase in pro-osteoarthritic signaling in the joint soft tissue. Similarly, a decrease in cortical and trabecular bone volume of the tibia was observed. Treatment with the SOD mimetic preserved the trabecular bone, articular cartilage and the menisci after 35 days aboard the ISS, but had limited efficacy retaining that recovery after 120 days of weight bearing, and after 75 days on orbit. Antioxidants including BuOE may serve as a potential countermeasure option to protect musculoskeletal health during spaceflight missions, and continued use may be necessary upon reaching a destination.

Ternary complex of soluble undenatured type II collagen-hydrophobic phytochemical-chondroitin sulfate facilitates high stability and targeted intestinal release properties to active substance

Researchers have reported that soluble undenatured type II collagen (SC II) and hydrophobic phytochemicals (HPs) can ameliorate osteoarthritis (OA) through several mechanisms. However, the solubility of HPs, the stability of SC II, and the bio-accessibility of both need to be greatly improved before they can be successfully used for this purpose. In this study, two common HPs, curcumin (CUR, a hydrophobic polyphenol) and astaxanthin (AST, a carotenoid), were first loaded into SC II, which was then complexed with chondroitin sulfate (CS) to form ternary complexes: SC II-HP-CS. The results showed that SC II had the highest loading capacity for CUR (19.00 ± 0.76 μg/mg) and AST (21.15 ± 1.67 μg/mg) at pH 2.0. The CUR and AST bound to the SC II through non-covalent interactions (mainly hydrophobic interaction) and they both existed in an amorphous form within the complexes. In addition, the binding affinity and hydrophobic interaction between SC II and CUR was higher than those of AST. The thermal stability of the SC II-CUR-CS (Td = 118.0 ± 2.1 °C) and SC II-AST-CS (Td = 118.8 ± 3.5 °C) complexes were significantly higher than that of the SC II-CUR (Td = 104.27 ± 0.28 °C) and SC II-AST (Td = 103.8 ± 1.6 °C) complexes. SC II-HP complexes dissolved in gastric fluids, resulting in serious degradation of the SC II, while SC II-HP-CS complexes existed in an insoluble form to protect the triple helix structure of SC II (24-46 % retained). The CUR release (94.2 ± 5.8 %) and the free radical scavenging activity (84.6 ± 5.3 %) of SC II-CUR-CS was relatively high after 6 h of intestinal digestion, while AST in SC II-AST and SC II-AST-CS had low solubility and antioxidant activity. Therefore, the ternary complex of SC II-HP-CS was more advantageous as multifunctional delivery systems for the encapsulation, protection, and controlled release of hydrophobic polyphenols, which may provide guidance for the synergistic use of hydrophobic polyphenols and SC II to improve OA.

Unraveling the Dual Anti-Inflammatory and Antioxidant Mechanisms of Acteoside: Computational Insights and Experimental Validation

Acteoside (ACT) is one of the primary bioactive ingredients in Cistanche tubulosa (Schenk). Its remarkable efficacy in treating immune-related and inflammatory disorders has garnered significant interest among scientific circles. However, the anti-inflammatory and antioxidant effects of ACT and its underlying molecular mechanisms require further investigation. In this study, pharmacophore-based reverse docking and molecular dynamics simulations identified potential anti-inflammatory targets in silico. Studies conducted in vitro with lipopolysaccharide (LPS)-induced RAW264.7 cells validated the anti-inflammatory properties of ACT. Methyl thiazolyl tetrazolium (MTT) and lactate dehydrogenase (LDH) assays indicated ACT's non-toxic and growth-promoting effects on cells. ACT significantly reduced nitric oxide (NO) and reactive oxygen species (ROS) production and restored levels of antioxidant enzymes. It also decreased pro-inflammatory cytokines. Western blotting assays indicated that ACT inhibited p38, TNF-α, PI3 K/AKT, and NF-κB signaling pathways. These findings underscore ACT's ability to mitigate acute inflammation in RAW264.7 cells by modulating key signaling pathways and provide the scientific basis for enhancing the medicinal value of ACT and future drug development.

Meta-analysis of the Relationship Between Zinc and Copper in Patients with Osteoarthritis

This study aims to explore the relationship between osteoarthritis and the trace elements zinc and copper and to provide a theoretical basis for research on the related mechanisms for the prevention, diagnosis, and treatment of osteoarthritis. We searched all the literature indexed in Web Of Science, Embase, and PubMed as of January 10, 2024, summarized the zinc and copper detection indexes in patients with osteoarthritis, obtained clinical data through literature screening, quality assessment, and data extraction, and analyzed the data using Revman 5.4. A total of 13 papers were included in this study, totaling 7983 study subjects. These were divided into osteoarthritis and healthy control groups. The results from the meta-analysis showed that in patients with osteoarthritis, circulating copper levels, but not zinc levels, were significantly higher compared to healthy individuals. The level of copper in the blood of patients with osteoarthritis is significantly higher than that of healthy people.

Association of dietary acid load with inflammatory markers, oxidative stress, and clinical features in patients with knee osteoarthritis

Knee osteoarthritis (KOA) is a prevalent chronic condition characterized by inflammation and oxidative stress, particularly in individuals over 40. Dietary factors, specifically dietary acid load (DAL), may influence these pathological processes. However, the relationship between DAL and inflammatory markers, oxidative stress, and clinical features in patients with KOA remains unexplored. This cross-sectional study involved 147 participants aged 40 and above diagnosed with moderate to severe bilateral primary KOA. Dietary intake was assessed using a validated food frequency questionnaire, and DAL was quantified using Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP) indices. Clinical symptoms were evaluated using the WOMAC Index. Biochemical markers of oxidative stress and inflammation were measured from serum samples. Higher PRAL and NEAP scores were associated with increased levels of thiobarbituric acid reactive substances (TBARS) and total oxidant status (TOS), indicating elevated oxidative stress. Additionally, serum levels of inflammatory markers, including TNF-α and hs-CRP, positively correlated with higher DAL scores. Clinical assessments revealed that increased PRAL scores were related to greater severity of symptoms as measured by the WOMAC Index. This study demonstrates a significant association between dietary acid load and markers of inflammation and oxidative stress in KOA patients. These findings suggest that dietary modifications aimed at reducing acid load may serve as a beneficial adjunctive strategy in managing KOA and improving patient outcomes.

3D printing of stiff, tough, and ROS-scavenging nanocomposite hydrogel scaffold for in situ corneal repair

Despite significant advancements in hydrogels in recent years, their application in corneal repair remains limited by several challenges, including unfitted curvatures, inferior mechanical properties, and insufficient reactive oxygen species (ROS)-scavenging activities. To address these issues, this study introduces a 3D-printed corneal scaffold with nanocomposite hydrogel consisting of gelatin methacrylate (GelMA), poly (ethylene glycol) diacrylate (PEGDA), Laponite, and dopamine. GelMA and PEGDA act as matrix materials with photo-crosslinking abilities. As a two-dimensional nanoclay, Laponite enhances the rheological properties of the hydrogel, making it suitable for 3D printing. Dopamine self-polymerizes into polydopamine (PDA), providing the hydrogel with ROS-scavenging activity. The incorporation of Laponite and the synergistic effect of PDA endow the hydrogel with good mechanical properties. In vitro investigations demonstrated the cytocompatibility of GelMA-PEGDA-Laponite-dopamine (GPLD) hydrogel and its ROS-scavenging activity. Furthermore, in vivo experiments using a rabbit model of lamellar keratoplasty showed accelerated corneal re-epithelialization and complete stromal repair after the implantation of the 3D-printed scaffold. Overall, due to its high bioactivity and simple preparation, the 3D-printed scaffold using GPLD hydrogel offers an alternative for corneal repair with potential for clinical translation. STATEMENT OF SIGNIFICANCE: The clinical application of hydrogel corneal scaffolds has been constrained by their inadequate mechanical properties and the complex microenvironment created by elevated levels of ROS post-transplantation. In this study, we developed a kind of nanocomposite hydrogel by integrating Laponite and dopamine into GelMA and PEGDA. This advanced hydrogel was utilized to 3D print a corneal scaffold with high mechanical strength and ROS-scavenging abilities. When applied to a rabbit model of lamellar keratoplasty, the 3D-printed scaffold enabled complete re-epithelialization of the cornea within one week. Three months after surgery, the corneal stroma was fully repaired, and regeneration of corneal nerve fibers was also observed. This 3D-printed scaffold demonstrated exceptional efficacy in repairing corneal defects with potential for clinical translation.

Clinical-grade extracellular vesicles derived from umbilical cord mesenchymal stromal cells: preclinical development and first-in-human intra-articular validation as therapeutics for knee osteoarthritis

Osteoarthritis (OA) is a joint disease characterized by articular cartilage degradation. Persistent low-grade inflammation defines OA pathogenesis, with crucial involvement of pro-inflammatory M1-like macrophages. While mesenchymal stromal cells (MSC) and their small extracellular vesicles (sEV) hold promise for OA treatment, achieving consistent clinical-grade sEV products remains a significant challenge. This study aims to develop fully characterized, reproducible, clinical-grade batches of sEV derived from umbilical cord (UC)-MSC for the treatment of OA while assessing its efficacy and safety. Initially, a standardized, research-grade manufacturing protocol was established to ensure consistent sEV production. UC-MSC-sEV characterization under non-cGMP conditions showed consistent miRNA and protein profiles, suggesting their potential for standardized manufacturing. In vitro studies evaluated the efficacy, safety, and potency of sEV; animal studies confirmed their effectiveness and safety. In vitro, UC-MSC-sEV polarized macrophages to an anti-inflammatory M2b-like phenotype, through STAT1 modulation, indicating their potential to create an anti-inflammatory environment in the affected joints. In silico studies confirmed sEV's immunosuppressive signature through miRNA and proteome analysis. In an OA mouse model, sEV injected intra-articularly (IA) induced hyaline cartilage regeneration, validated by histological and μCT analyses. The unique detection of sEV signals within the knee joint over time highlights its safety profile by confirming the retention of sEV in the joint. The product development of UC-MSC-sEV involved refining, standardizing, and validating processes in compliance with GMP standards. The initial assessment of the safety of the clinical-grade product via IA administration in a first-in-human study showed no adverse effects after a 12 month follow-up period. These results support the progress of this sEV-based therapy in an early-phase clinical trial, the details of which are presented and discussed in this work. This study provides data on using UC-MSC-sEV as local therapy for OA, highlighting their regenerative and anti-inflammatory properties and safety in preclinical and a proof-of-principle clinical application.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

A natural polyphenolic nanoparticle--knotted hydrogel scavenger for osteoarthritis therapy

Exploring highly efficient and cost-effective biomaterials for osteoarthritis (OA) treatment remains challenging, as current therapeutic strategies are difficult to eradicate the excessive reactive oxygen species (ROS) and nitric oxide (NO) at damaged sites. Tea polyphenol (TP) nanoparticles (NPs), a nature-inspired antioxidant in combination with 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), a NO scavenger, could provide maximized positive therapeutic effects on OA by eradicating both ROS and NO. Notably, this combination not only improves the half-life of the TP monomer and the drug loading efficiency of carboxy-PTIO but also prevents nitrite from being harmful to tissue. Moreover, the protonation ability of carboxy-PTIO allows smart acid-responsive release in response to environmental pH, which provides conditioned treatment strategies for OA. In in vitro experiments, TP/PTIO NPs downregulated proinflammatory cytokine release via synergistic removal of ROS and NO and suppression of ROS/NF-κB and iNOS/NO/Caspase-3 signaling. For in vivo experiments, NPs were cross-linked with 4-arm-PEG-SH to form an injectable hydrogel system. The release of TP and carboxy-PTIO from the system efficiently prevents cartilage inflammation and damage via similar signaling pathways. Overall, the proposed system provides an efficient approach for OA therapy.

M13, an anthraquinone compound isolated from Morinda officinalis alleviates the progression of the osteoarthritis via the regulation of STAT3

BACKGROUND

Osteoarthritis (OA) is characterized by the progressive deterioration of articular cartilage, leading to joint pain and functional impairment. OA severely impacts quality of life and presents a substantial societal burden. Currently, effective treatment options remain limited. Morinda officinalis (MO), a traditional Chinese herb, is commonly used to treat rheumatoid arthritis and alleviate joint pain. M13, an anthraquinone extracted from MO, has shown significant anti-inflammatory properties, making it a promising candidate for the treatment of OA. However, its role in inhibiting OA progression and the mechanisms involved remain poorly understood.

PURPOSE

The objective of this study is to examine the impact of M13 on osteoarthritis and uncover the mechanisms.

METHODS

The effects of M13 on OA were assessed using TNF-α induced chondrocyte models and mice with destabilization of the medial meniscus (DMM). Celecoxib was used as a positive control. We evaluated the expression of factors related to chondrocyte degeneration and inflammation through qRT-PCR, immunoblotting, and immunofluorescence. Chondrocyte viability was measured using CCK-8 assays, EdU staining, and flow cytometry. Molecular docking, molecular dynamics simulations and isothermal titration calorimetry (ITC) were performed to evaluate the binding efficacy of target proteins. Additionally, the therapeutic effects of M13 in OA mice were confirmed through in vivo experiments.

RESULTS

In primary murine chondrocytes, M13 rescued TNF-α-induced matrix degradation and loss of vitality while suppressing ROS generation. Mechanistically, STAT3 was identified as a target protein of M13, through which M13 mitigated OA by inhibiting the STAT3 signaling pathway. Further in vivo experiments demonstrated that M13 reduced the scores of the Osteoarthritis Research Society International (OARSI), alleviating cartilage impairment. M13 enhanced levels of collagen II and aggrecan in cartilage tissue while decreasing the amounts of cartilage-degrading proteins ADAMTS-5 and MMP13.

CONCLUSION

This is the first study to validate that M13 mitigates the inflammation and damage in cartilage tissue by blocking the STAT3 signaling pathway. These findings hold promise for enhancing innovative clinical interventions targeting OA.

A Panoramic Review on the Management of Rheumatoid Arthritis through Herbalism

Arthritis is a chronic inflammatory condition that affects millions of individuals worldwide. The conventional treatment options for arthritis often come with limitations and potential side effects, leading to increased interest in herbal plants as alternative therapies. This article provides a comprehensive overview of the use of herbal plants in arthritis treatment, focusing on their traditional remedies, active components, mechanisms of action, and pharmaceutical approaches for enhancing their delivery. Various herbal plants, including turmeric, ginger, Boswellia, and willow bark, have shown anti-inflammatory and analgesic properties, making them valuable options for managing arthritis symptoms. The active components of these herbal plants, such as curcumin, gingerols, and boswellic acids, contribute to their therapeutic effects. To enhance the delivery of herbal medicines, pharmaceutical approaches like nanoparticle-based drug delivery systems, liposomes, polymeric nanoparticles, nanoemulsions, microneedles, and inhalation systems have been explored. These approaches aim to improve bioavailability, targeted delivery, and controlled release of herbal compounds. Safety considerations, including potential interactions with medications and the risk of allergic reactions, are also discussed. Future perspectives for this field involve conducting well-designed clinical studies, enhancing standardization and quality control measures, exploring novel drug delivery systems, and fostering collaborations between traditional medicine practitioners and healthcare professionals. Continued research and development in these areas will help unlock the full potential of herbal plants in arthritis treatment, offering personalized and effective care for affected individuals.

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

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

Garlic-derived Exosomes Alleviate Osteoarthritis Through Inhibiting the MAPK Signaling Pathway

Osteoarthritis (OA) is the most common degenerative joint disease affecting millions of people worldwide. Garlic-derived exosomes (GDEs) are nanoparticles extracted from garlic that exhibit anti-inflammatory effects on other diseases, but the effect of GDEs on OA has not been elucidated. In this study, GDEs were extracted and characterized. Chondrocytes were treated with IL-1β and incubated with GDEs in vitro, and the expression of cartilage matrix components (collagen II and aggrecan) and matrix degrading enzymes (MMP3 and MMP9) was evaluated via Western blotting. Changes in the MAPK pathway was also examined using Western blotting. The transcriptomic changes associated with GDE intervention were evaluated using high-throughput RNA-seq method. In vivo, we used anterior cruciate ligament transection (ACLT) combined with destabilization of the medial meniscus (DMM) surgery to establish a mouse OA model, and GDEs was intraarticularly injected into the joint cavity. The therapeutic effect of GDE was evaluated by behavioral and histopathological analysis. The results showed that IL-1β treatment inhibited the expression of collagen II and aggrecan, and upregulated the expression of MMP3 and MMP9, while GDE intervention alleviated these effects. GDEs also inhibited the phosphorylation of ERK, JNK, and P38. In vivo, GDE alleviated the sensitivity to heat stimulation and altered walking gait in a mouse OA model. Histopathological analysis indicated that GDE intervention ameliorated joint destruction in the knee joint without obvious toxicity. The results proved that GDEs alleviated the progression of OA in vitro and in vivo, and may be a potential disease-modifying drug for OA.

TFAP2A Promotes Cell Progression and Suppresses Ferroptosis in Lung Adenocarcinoma via Activating Transcription of CST1

Lung adenocarcinoma (LUAD) is a common type of lung cancer with complicated pathological mechanism. Transcription Factor AP-2 Alpha (TFAP2A) and Cysteine protease inhibitor 1 (CST1) are upregulated genes in LUAD samples, accordingly, we focused on clarifying the role of TFAP2A/CST1 axis in LUAD. Expression analysis was performed using real-time quantitative polymerase chain reaction and western blot. Cellular behaviors were detected by colony formation assay, EdU assay, wound healing assay and flow cytometry. Ferroptosis was assessed by oxidative indicators, Fe2+ level and related proteins. TFAP2A and CST1 interaction was analyzed via ChIP assay and dual-luciferase reporter assay. TFAP2A function in vivo was evaluated by xenograft tumor assay. CST1 was overexpressed in LUAD samples and cells. Downregulation of CST1 inhibited proliferation, migration but it promoted apoptosis and ferroptosis of LUAD cells. TFAP2A interacted with the promoter of CST1 to up-regulate CST1 expression. TFAP2A regulated the malignant behaviors and ferroptosis of LUAD cells by targeting CST1. TFAP2A affected LUAD tumor growth via mediating CST1. All these data proved that TFAP2A/CST1 axis contributed to proliferation, migration while it suppressed apoptosis and ferroptosis in LUAD.

Chronic intermittent hypobaric hypoxia alleviates early-stage posttraumatic osteoarthritis via NF-κB/Nrf2 pathway in mice

BACKGROUND

Posttraumatic osteoarthritis (PTOA) is directly associated with early acute articular cartilage injury. Inhibition of cartilage destruction immediately following joint damage can effectively slow or prevent PTOA progression. Therefore, we sought to determine intervention targets and therapeutic strategies in the acute stage of cartilage injury. The benefits of chronic intermittent hypobaric hypoxia (CIHH) extend to various body tissues, but its impact on acute cartilage injury remains unclear. We selected PTOA initiation as the therapeutic window and administered CIHH treatment immediately following cartilage injury initiation to investigate its protective effect on cartilage and molecular mechanism changing with time-varying.

METHODS

The non-invasive PTOA mouse model was established by applying a single rapid specific impact force to the right knee's tibial plateau, initiating load-induced PTOA development, closely resembling the pathological changes in human diseases. Following loading, we inhibited cartilage destruction by treating mice immediately in a hypobaric chamber with a hypobaric hypoxia mimic at 5000 m altitude. Cohorts of mice subjected to distinct experimental conditions were monitored for 3, 7, 14 or 28 days. Safranin O-Fast Green staining, Immunohistochemistry, immunofluorescence, ELISA, and western blotting were performed to evaluate the therapeutic effects of CIHH on cartilage in vivo. The nuclear translocation of NF-κB p65 and Nrf2 were detected by immunofluorescence.

RESULTS

The results showed that inhibiting cartilage destruction using CIHH immediately following acute articular cartilage injury initiation delayed the progression of PTOA, decreased the Mankin score and suppressed the expression of proinflammatory factors, including iNOS, NO, TNF-α, and IL-1β. Meanwhile, immediate CIHH treatment reduced levels of the catabolic enzymes ADAMTS5 and MMP13 in the cartilage matrix, reversed degradation of Collagen II and COMP, and inhibited oxidative stress by decreasing ROS levels. Moreover, CIHH suppressed NF-κB signaling by activating the Nrf2 in vivo studies.

CONCLUSION

Our study demonstrated that immediate CIHH treatment following cartilage injury initiation can attenuate load-induced cartilage damage by activating Nrf2/HO-1 and inhibiting the NF-κB p65 signalling pathways to counteract oxidative stress and inflammatory reactions, enhance the metabolic balance of the cartilage matrix and delay cartilage degeneration. This treatment may represent a potential therapeutic strategy for limiting PTOA progression.

Isoliensinine suppresses chondrocytes pyroptosis against osteoarthritis via the MAPK/NF-κB signaling pathway

BACKGROUND

Isoliensinine is an active compound derived from Nelumbo nucifera which has long been used for its anti-inflammatory properties. However, the mechanism of Isoliensinine in the treatment of osteoarthritis is poorly known.

PURPOSE

The present study aims to investigate whether Isoliensinine could alleviate osteoarthritis by regulating MAPK/NF-κB signaling pathway-mediated pyroptosis.

METHODS

Network pharmacology and KEGG enrichment analysis were used to identify the therapeutic targets of Isoliensinine for OA. Molecular docking was used to confirm the binding ability of Isoliensinine and related proteins. In vitro, chondrocytes were stimulated with IL-1β to construct an inflammatory model and treated with Isoliensinine. The viability of the cells was assessed using the CCK-8 kit. The apoptosis rate of cells was measured using Annexin V-FITC/PI assay. And assessed the levels of ROS, lipid-ROS, and mitochondrial membrane potential. Corresponding assay kits were utilized to measure the levels of MDA and SOD. Subsequently, the anabolic and catabolic markers in chondrocytes, alongside inflammatory targets were measured by RT-PCR and Western blot. The expression level of pyroptosis and MAPK/NF-κB signaling pathway-related targets was examined. Furthermore, we constructed a rat osteoarthritis model using ACLT surgery. We then assessed the progression of osteoarthritis by Micro-CT, H&E staining, S&F staining and immunohistochemistry.

RESULTS

Enrichment analysis showed that Isoliensinine treatment of osteoarthritis may be through the MAPK/NF-κB pathway, and molecular docking showed that Isoliensinine and MAPK/NF-κB pathway proteins had a good binding ability. Data showed that Isoliensinine could reduce ECM degradation and inflammation, and inhibit IL-1β-induced apoptosis. It also mitigated ROS and LPO activation, regulated mitochondrial dysfunction, and reduced intracellular oxidative stress levels. Furthermore, Western blot showed that Isoliensinine also inhibited the activation of the MAPK/NF-κB pathway, thereby inhibiting the pyroptosis of chondrocytes. In vivo, Micro-CT, H&E staining and S&F staining results showed that Isoliensinine could effectively improve joint damage caused by osteoarthritis. And IHC analyses indicated NLRP3, MMP3 protein expression were significantly diminished and Collagen II expression was increased in the Isoliensinine treatment groups.

CONCLUSION

In conclusion, our study suggested that Isoliensinine mitigates ECM degradation, oxidative stress, chondrocytes apoptosis, and pyroptosis through the inhibition of the MAPK and NF-κB pathways, thereby delaying the progression of osteoarthritis.

Wedelolactone alleviates inflammation and cartilage degeneration by suppressing the NF-κB signaling pathway in osteoarthritis

Inflammation and extracellular matrix (ECM) degradation are two major factors involved in the pathogenesis of osteoarthritis (OA). Wedelolactone, a natural compound classified as a coumestan, is isolated from the medicinal plants Eclipta alba and Wedelia calendulacea. In this study, we assessed the protective effects of Wedelolactone on chondrocytes in OA. Our findings show that pretreatment with Wedelolactone effectively inhibited the IL-1β-induced upregulation of COX‑2, iNOS, TNF-α, and IL6 in chondrocytes, contributing to inflammation suppression. Moreover, pretreatment with Wedelolactone followed by IL-1β treatment significantly increased the expression of Collagen II and SOX9, while decreasing the expression of Adamts5, MMP1, MMP3, and MMP13, thereby promoting ECM protection. Through Network pharmacology Analysis, we identified 14 key targets that link Wedelolactone and OA. GO and KEGG pathway analysis suggested that Wedelolactone primarily impacted OA by targeting inflammatory responses, particularly the NF-κB signaling pathway. Further studies demonstrated Wedelolactone prevented IL-1β-induced activation of NF-κB signaling pathway by inhibiting the translocation of p65 and the preventing the degradation of IκBα in human chondrocytes. Molecular docking studies also indicated that Wedelolactone can directly bind to the NF-κB complex, thereby inhibited the nuclear localization of p65. In vivo experiments demonstrated that Wedelolactone can alleviate cartilage damage in DMM mice model. In summary, Wedelolactone appears to mitigate inflammation and cartilage degeneration by suppressing the NF-κB signaling pathway, thereby alleviating OA progression. Our results suggested Wedelolactone may offer therapeutic advantages for OA treatment.

Cartilage-targeting peptide-modified cerium oxide nanoparticles alleviate oxidative stress and cartilage damage in osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a degenerative joint disease that leads to a substantial decline in the well-being of older individuals. Chondrocyte senescence and the resultant damage to cartilage tissue, induced by elevated levels of reactive oxygen species within the joint cavity, are significant causative factors in OA development. Cerium oxide nanoparticles (CeONPs) present a promising avenue for therapeutic investigation due to their exceptional antioxidant properties. However, the limited effectiveness of drugs in the joint cavity is often attributed to their rapid clearance by synovial fluid.

METHODS

Polyethylene glycol-packed CeONPs (PEG-CeONPs) were synthesized and subsequently modified with the cartilage-targeting peptide WYRGRLGK (WY-PEG-CeO). The antioxidant free radical activity and the mimetic enzyme activity of PEG-CeONPs and WY-PEG-CeO were detected. The impact of WY-PEG-CeO on chondrocytes oxidative stress, cellular senescence, and extracellular matrix degradation was assessed using in vitro assays. The cartilage targeting and protective effects were explored in animal models.

RESULTS

WY-PEG-CeO demonstrated significant efficacy in inhibiting oxidative stress, cellular senescence, and extracellular matrix degradation in OA chondrocytes. The underlying mechanism involves the inhibition of the PI3K/AKT and MAPK signaling pathways. Animal models further revealed that WY-PEG-CeO exhibited a prolonged residence time and enhanced penetration efficiency in cartilage tissue, leading to the attenuation of pathological changes in OA.

CONCLUSIONS

These findings suggest that WY-PEG-CeO exerts therapeutic effects in OA by inhibiting oxidative stress and suppressing the over-activation of PI3K/AKT and MAPK signaling pathways. This investigation served as a fundamental step towards the advancement of CeONPs-based interventions, providing potential strategies for the treatment of OA.

Ferroptosis and its role in osteoarthritis: mechanisms, biomarkers, and therapeutic perspectives

Osteoarthritis (OA) is one of the leading causes of disability worldwide, characterized by a complex pathological process involving cartilage degradation, synovial inflammation, and subchondral bone remodeling. In recent years, ferroptosis, a form of programmed cell death driven by iron-dependent lipid peroxidation, has been recognized as playing a critical role in the onset and progression of OA. Investigating the molecular mechanisms of ferroptosis and its involvement in OA may offer novel strategies for diagnosing and treating this disease. This review first outlines the core mechanisms of ferroptosis, with a particular focus on the roles of critical molecules such as Glutathione Peroxidase 4 (GPX4), Transferrin Receptor 1 (TfR1), and Nuclear Receptor Coactivator 4 (NCOA4). Subsequently, this study examines the specific impacts of ferroptosis on the pathophysiology of OA. Building on this, the potential of ferroptosis-related biomarkers for OA diagnosis and treatment is highlighted, along with proposed therapeutic strategies targeting ferroptosis regulation. This review aims to deepen the understanding of ferroptosis mechanisms and advance the clinical application of regulatory therapies for OA.

Exploring the Efficacy of Joint Lavage in Knee Osteoarthritis: A Focus on Cytokines, Degrading Enzymes, and Oxidative Stress

PURPOSE/AIM

This study aimed to assess the effectiveness of joint lavage in managing knee osteoarthritis (OA) by evaluating its effect on pain relief, inflammatory markers, cartilage-degrading enzymes, and oxidative stress.

METHODS

Seventy patients with Kellgren-Lawrence grade 2 or 3 knee OA were selected for this single-center study. Joint lavage was performed, and pain and function were measured using the visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at baseline and 24 weeks postintervention. Synovial fluid samples were collected at baseline, before lavage, and 24 weeks postintervention. Samples were stored at -80°C and analyzed in batches to minimize variability. At the time of analysis, the samples were thawed and evaluated for levels of proinflammatory cytokines, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), matrix metalloproteinase-3 (MMP-3), and total oxidant status (TOS), and oxidative stress index (OSI).

RESULTS

Postintervention, VAS, and WOMAC scores significantly decreased (P < 0.001), with 100% achieving the minimal clinically important difference (MCID). Patient acceptable symptom state (PASS) rates varied: VAS (80%), WOMAC pain (50%), function (81.4%), and total (84.3%). Cytokine levels (IL-1β, IL-6, TNF-α) and MMP-3 significantly decreased (P < 0.001), along with TOS and OSI. Baseline TNF-α, IL-6, and IL-1β levels were significantly correlated with improvements in VAS and WOMAC scores. Moderate correlations were observed between reductions in IL-6/TNF-α and improvements in VAS/WOMAC. No significant associations were found between confounders and outcomes.

CONCLUSIONS

Joint lavage resulted in marked pain relief and functional improvement while significantly reducing inflammatory markers, cartilage-degrading enzymes, and oxidative stress.

Kongensin A targeting PI3K attenuates inflammation-induced osteoarthritis by modulating macrophage polarization and alleviating inflammatory signaling

The inflammatory microenvironment, polarization of macrophages towards the M1 phenotype, and consequent matrix degradation and senescence of chondrocytes are primary contributors to the degeneration of knee joint cartilage, further exacerbating the progression of osteoarthritis (OA). Kongensin A (KA) is a recently identified natural plant extract exhibiting anti-necrotic apoptosis and anti-inflammatory properties, but the potential efficacy in alleviating OA remains uncertain. The current research lucubrated the effect of KA on the inflammatory microenvironment and macrophage polarization, as well as its regulatory function in extracellular matrix (ECM) metabolism and chondrocyte senescence. Our findings demonstrated that KA can suppress inflammatory signaling, maintain homeostasis between ECM anabolism and catabolism, and suppress chondrocytes senescence. Further investigation elucidated that the mechanism involves the suppression of the PI3K/AKT/NF-κB axis in chondrocytes under inflammatory conditions. Moreover, KA impeded M1 polarization of macrophages via inhibiting PI3K/AKT/NF-κB axis. Subsequently, we treated chondrocytes with macrophages-derived conditioned medium (CM) and revealed that KA can promote ECM anabolism and alleviate chondrocytes senescence by reprogramming macrophage polarization. Consistent with in vitro experiments, in vivo administration of KA demonstrated alleviated cartilage degeneration and delayed progression of OA. Collectively, through obstructing the PI3K/AKT/NF-κB axis, KA can reprogram macrophage polarization, promote matrix metabolism equilibrium, and alleviate chondrocytes senescence, thereby attenuating the pathology of OA. In conclusion, KA may emerge as a promising therapy for OA.

Association between the composite dietary antioxidant index and all-cause mortality in individuals with osteoarthritis via NHANES data

The impact of antioxidant intake on the prognosis of osteoarthritis (OA) patients remains unclear. The aim of this study was to investigate the relationship between the composite dietary antioxidant index (CDAI) and all-cause mortality in OA patients. A total of 35,590 participants with OA from the National Health and Nutrition Examination Survey (1999-2020) were included in this study. We analysed the associations between the CDAI and the risk of all-cause mortality in OA patients via a multivariate Cox regression model. Restricted cubic spline regression was used to investigate the dose-response associations between the CDAI and mortality. We also conducted stratified analyses and interaction tests to explore underlying effect modification. After multivariable adjustment, each one-unit increase in the CDAI was associated with a 2.1% reduction in the risk of mortality. Compared with those in the low CDAI group, the multivariate-adjusted hazard ratios (HRs) for mortality for patients in the high CDAI group were lower [Model 1 (HR 0.648, 95% CI 0.557-0.754), Model 2 (HR 0.739, 95% CI 0.627-0.871), and Model 3 (HR 0.788, 95% CI 0.661-0.941)]. We observed a negative nonlinear relationship between the CDAI and all-cause mortality (P < 0.05). Stratification analyses and interaction tests confirmed the robustness of the results. We found a negative nonlinear relationship between the CDAI and all-cause mortality in OA patients. A higher CDAI was significantly associated with a lower risk of mortality. These results highlight the potential advantages of monitoring and evaluating the CDAI status in preventing mortality among patients with OA.