Pathogenesis of Osteoarthritis: Risk Factors, Regulatory Pathways in Chondrocytes, and Experimental Models

Andrographolide suppresses fibrogenic phenotype of chondrocytes and ameliorates osteoarthritis by regulating miR-137/BMP7 axis

Background

Pathogenic degeneration of cartilage and the generation of fibrotic cartilage are crucial characteristics linked to the progression of osteoarthritis (OA). The current research aims to explore the potential function of the miR-137/BMP7 pathway in regulating the fibrogenic transition of chondrocytes associated with OA, as well as assess the therapeutic potential of andrographolide.

Methods

Samples of cartilage from the knees of patients with OA and individuals without OA were gathered to investigate the expression patterns of miR-137, BMP7, and markers associated with fibrosis. A cell model using primary chondrocytes stimulated with interleukin (IL)-1β was developed to study the involvement of the miR-137/BMP7 axis during the fibrogenic transition of these cells. Additionally, we utilized an animal model of OA in order to assess the beneficial effects of the anti-inflammatory natural compound andrographolide on the fibrogenesis induced by OA in vivo.

Results

Elevated levels of fibrogenic and inflammatory factors were linked to decreased miR-137 expression in OA samples. In IL-1β-treated chondrocytes, there was an upregulation of fibrogenic markers alongside a reduction in miR-137 levels. The overexpression of miR-137 inhibited fibrogenesis through the negative regulation of BMP7. Additionally, treatment with andrographolide was effective in attenuating the fibrogenic phenotype in chondrocytes and mitigating OA pathogenesis via modulating the miR-137/BMP7 pathway.

Conclusion

miR-137 downregulation and BMP7 overexpression might contribute to the fibrogenic features in OA-related chondrocytes. Andrographolide attenuates fibrogenic phenotype in chondrocytes and alleviates the severity of OA by modulating the miR-137/BMP7 axis.

From mundane to classic: Sinomenine as a multi-therapeutic agent

Sinomenine is an active substance extracted from the traditional Chinese medicine Sinomenium acutum. Sinomenine has been shown to mediate a wide range of pharmacological actions and is known to possess good anti-inflammatory, immunosuppressive, antitumor, neuroprotective, antiarrhythmic and other pharmacological effects. Understanding the underlying mechanisms and the association between the targets and the pharmaceutical effects on different diseases is crucial to the discovery and design of new treatment strategies. In this review, we aim to give a systematic and comprehensive overview of the research progress of sinomenine over the past 20 years. We first describe the metabolism of sinomenine in vivo and then summarize the pharmacological actions of sinomenine on different diseases. Furthermore, the potential binding properties of sinomenine and the potential of developing new sinomenine-based drugs are also reviewed. LINKED ARTICLES: This article is part of a themed issue Natural Products and Cancer: From Drug Discovery to Prevention and Therapy. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.10/issuetoc.

Comprehensive multi-omics approach reveals potential therapeutic targets and agents for osteoarthritis

BACKGROUND

The mechanisms underlying osteoarthritis (OA) remain unclear, and effective treatments are lacking. This study aims to identify OA-related genes and explore their potential in drug repositioning for OA treatment.

METHODS

Transcriptome-wide association studies (TWAS) were performed using genome-wide association studies summary data and expression quantitative trait loci data from the Genotype-Tissue Expression project. Differentially expressed genes between OA patients and healthy controls were identified using four datasets from the Gene Expression Omnibus database. Gene ontology and pathway enrichment analyses identified potential hub genes associated with OA. A network-based drug repositioning approach was applied to discover potential therapeutic drugs for OA.

RESULTS

Through TWAS and mRNA expression profiling, 7 and 167 OA-related genes were identified, respectively. From these, 128 OA-related genes were selected based on common biological processes. Using the maximal clique centrality algorithm, 10 core-related genes (JUN, VEGFA, FN1, CD44, PTGS2, STAT1, MAP 2K7, GRB2, EP300, and PXN) were identified for network-based drug repositioning. Consequently, 24 drugs were identified based on 128 OA-related genes and 23 drugs based on 10 core OA-related genes. Some identified drugs, such as dexamethasone, menadione, and hyaluronic acid, have been previously reported for OA and/or rheumatoid arthritis treatment. Network analysis also indicated that spironolactone, lovastatin, and atorvastatin may have potential in OA treatment.

CONCLUSION

This study identified potential OA-related genes and explored their roles in drug repositioning, suggesting the repurposing of existing drugs and the development of new therapeutic options for OA patients. Key message What is already known on this topic The exact pathogenesis of osteoarthritis (OA) remains unclear, and currently, there are no approved drugs that can prevent, halt, or inhibit the progression of OA. What this study adds We identified 128 OA-related genes and 10 core-related genes based on common biological processes revealed by TWAS and mRNA expression profiling. Using these genes, we discovered potential drugs for OA through the Network-based drug repositioning method. How this study might affect research, practice, or policy This study provides recommendations for repositioning existing drugs and developing new treatment options for patients with OA.

L-shaped association of bone mineral density with all-cause mortality in individuals with osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a common joint disease that poses a significant public health burden, particularly in older adults. Despite research on its impact, the role of bone mineral density (BMD) in OA prognosis remains underexplored. This study investigates the association between BMD, measured using dual-energy X-ray absorptiometry (DXA), and all-cause mortality in individuals with OA using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

This retrospective cohort study utilized NHANES data from 1999 to 2018, including participants aged 20 years and older (n = 55,081). After excluding individuals with missing BMD or mortality data, 1,573 participants diagnosed with OA were analyzed.

RESULTS

The multivariate-adjusted hazard ratio (HR) for BMD and all-cause mortality was 0.344 (0.153, 0.774), indicating a protective effect of higher BMD. We observed an L-shaped relationship between BMD and mortality: a 1-unit decrease in BMD was associated with a 97.3% increased HR for mortality when BMD was below 1.216 g/cm² (HR 0.027, 95% CI 0.010-0.069). No significant association was found for higher BMD levels (HR 4.490, 95% CI 0.431-46.754). In age-stratified analysis, a significant association was found in both those under and over 50 years old.

CONCLUSIONS

This study reveals an L-shaped association between BMD and all-cause mortality in individuals aged 20 and older with OA, underscoring the importance of maintaining bone health in this population. These findings highlight BMD as a prognostic marker and suggest that monitoring BMD could improve clinical outcomes for OA patients.

CLINICAL TRIAL NUMBER

Not applicable.

Microfluidic chip-based co-culture system for modeling human joint inflammation in osteoarthritis research

Here we present a microfluidic model that allows for co-culture of human osteoblasts, chondrocytes, fibroblasts, and macrophages of both quiescent (M0) and pro-inflammatory (M1) phenotypes, maintaining initial viability of each cell type at 24 h of co-culture. We established healthy (M0-based) and diseased (M1-based) joint models within this system. An established disease model based on supplementation of IFN-γ and lipopolysaccharide in cell culture media was used to induce an M1 phenotype in macrophages to recapitulate inflammatory conditions found in Osteoarthritis. Cell viability was assessed using NucBlue™ Live and NucGreen™ Dead fluorescent stains, with mean viability of 83.9% ± 14% and 83.3% ± 12% for healthy and diseased models, respectively, compared with 93.3% ± 4% for cell in standard monoculture conditions. Cytotoxicity was assessed via a lactate dehydrogenase (LDH) assay and showed no measurable increase in lactate dehydrogenase release into the culture medium under co-culture conditions, indicating that neither model promotes a loss of cell membrane integrity due to cytotoxic effects. Cellular metabolic activity was assessed using a PrestoBlue™ assay and indicated increased cellular metabolic activity in co-culture, with levels 5.9 ± 3.2 times mean monolayer cell metabolic activity levels in the healthy joint model and 5.3 ± 3.4 times mean monolayer levels in the diseased model. Overall, these findings indicate that the multi-tissue nature of in vivo human joint conditions can be recapitulated by our microfluidic co-culture system at 24 h and thus this model serves as a promising tool for studying the pathophysiology of rheumatic diseases and testing potential therapeutics.

Advancements in regenerative medicine: a comprehensive review of stem cell and growth factor therapies for osteoarthritis

Osteoarthritis (OA) is a widely encountered degenerative joint disorder marked by gradual cartilage deterioration, inflammation, and pain, which collectively impose considerable strain on global healthcare systems. While traditional therapies typically offer relief from symptoms, they do not tackle the core pathophysiological aspects of the disease. Regenerative medicine has recently risen as a promising field for addressing OA, capitalizing on the regenerative capabilities of stem cells and growth factors to foster tissue healing and renewal. This thorough review delves into the most recent progress in stem cell and growth factor treatments for OA, covering preclinical studies, clinical trials, and novel technological developments. We discuss the diverse origins of stem cells, such as mesenchymal stem cells (MSCs), induced pluripotent stem cells (iPSCs), and adipose-derived stem cells (ASCs), underscoring their therapeutic actions and effectiveness in both preclinical and clinical environments. Moreover, we explore contributions of growth factors like transforming growth factor (TGF)-β, platelet-derived growth factor (PDGF), and insulin-like growth factor (IGF) in modifying OA's pathology and enhancing tissue restoration. Additionally, this review discusses the hurdles and constraints tied to current regenerative strategies, including the standardization of cell sources, the refinement of delivery techniques, and considerations for long-term safety. By meticulously assessing the latest research outcomes and technological breakthroughs, this review aims to shed light on the potential of stem cell and growth factor therapies as forthcoming therapeutic options for OA, thereby propelling forward the domain of regenerative medicine and enhancing clinical results for individuals afflicted with this incapacitating ailment.

Anti-inflammatory activity of the combination Ardisia humilis Vahl. and Curcuma xanthorrhiza Roxb. extract on an osteoarthritis rat model

This study aimed to evaluate the anti-inflammatory activity of the combination of Ardisia humilis Vahl. and Curcuma xanthorrhiza Roxb. (AC) extract in monosodium iodoacetate (MIA)-induced osteoarthritis (OA) rat model. AC was administered orally to OA rats (240, 480, and 960 mg/kg bw) for three weeks. The control and model groups comprised OA rats treated with diclofenac sodium and carrier, respectively. AC-treated rats exhibited a significant reduction in oedema volume compared to those of the model group (p < 0.05). Notably, AC, at 960 mg/kg bw, significantly decreased inflammatory cytokines TNF-α and IL-1β, along with matrix metalloproteinase-9 (MMP-9) levels compared to those of the model group (p < 0.05). AC's attenuation of OA progression was also observed through haematoxylin and eosin (H&E) and Safranin O-fast green analysis. A phytochemical study showed AC contained phenolic, flavonoid, curcumin, demethoxycurcumin, and bisdemethoxycurcumin compounds. This study concludes that AC alleviated OA progression through anti-inflammatory effects and depressed MMP-9 levels.

Research progress and prospect of MAPK signaling pathway in knee osteoarthritis

The knee joint, one of the most vulnerable joints in the human body, is susceptible to degenerative changes due to factors such as aging, obesity, trauma, inflammation, and genetic predisposition. These factors contribute to primary or secondary degeneration of knee joint cartilage and bone hyperplasia. Knee osteoarthritis (KOA), a prevalent condition particularly among the elderly, significantly impacts patients' quality of life. Aberrant activation of cellular signaling pathways, namely the NF-κB, MAPK, and Wnt pathways, has been identified as a key factor in the pathogenesis of KOA. These pathways contribute to inflammation, cartilage degradation, and disruption of the anabolic-catabolic balance within articular cartilage. Understanding the precise roles of these pathways is crucial for developing targeted therapies to prevent and treat knee OA. Therefore, further exploration of the pathogenesis of knee osteoarthritis is essential to develop more effective therapeutic strategies.

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.

Advancing Osteoarthritis Research: Insights from Rodent Models and Emerging Trends

Osteoarthritis (OA) is a degenerative joint disease that affects millions of individuals worldwide, causing pain, disability, and a significant burden on public health. Preclinical research using animal models is essential to our understanding of the underlying pathogenesis of OA and developing therapeutic strategies. Rodent models, in particular, have become indispensable in studying OA due to their ability to mimic various features of human disease. This review provides an overview of commonly used rodent models of OA, including surgical induction (e.g., destabilization of the medial meniscus and anterior cruciate ligament transection), chemical induction (e.g., monoiodoacetate-induced cartilage degeneration), and genetically modified models. Additionally, age-related OA models that naturally develop OA-like symptoms in aged rodents are also discussed. Despite their utility, rodent models face limitations in fully recapitulating the complexity of human OA. Emerging trends in OA research, including the use of 3D imaging for joint analysis, molecular profiling for deeper insights into disease mechanisms, and advancements in biomarkers for early detection and treatment, are highlighted. These innovations provide new opportunities to refine existing models and enhance the translation of findings to clinical therapies. This critical review provides comprehensive information for researchers working in OA and related fields, promoting a better understanding of the available rodent models and their applications in OA research.

Osteoclast-derived apoptotic bodies accelerate the pathological progression of osteoarthritis via disturbing subchondral bone remodeling

Objective

To investigate the role of osteoclast-derived apoptotic bodies (OC-ABs) in osteoarthritis (OA), specifically their impact on subchondral bone remodeling and disease progression, and to explore potential therapeutic strategies targeting OC-AB-induced pathways.

Methods

We utilized a mouse model of anterior cruciate ligament transection (ACLT) to simulate post-traumatic osteoarthritis (PTOA). Levels of OC-ABs were assessed in subchondral bone and correlated with OA severity. Additionally, apoptotic body-deficient MRL/lpr mice were analyzed to evaluate the direct contribution of OC-ABs to OA progression and subchondral bone remodeling. The involvement of OC-ABs in osteogenesis was further examined using mesenchymal stem cells (MSCs), with a focus on the RANKL reverse signaling pathway. The therapeutic potential of rapamycin to counteract OC-AB effects was tested.

Results

Increased OC-AB accumulation in subchondral bone was positively correlated with OA severity in ACLT-induced mice. Apoptotic body-deficient MRL/lpr mice demonstrated slower OA progression and maintained more stable subchondral bone architecture, indicating a pathogenic role of OC-ABs in OA. OC-ABs significantly stimulated osteogenesis in MSCs via the RANKL reverse signaling pathway. Treatment with rapamycin effectively reversed OC-AB-induced subchondral bone formation, mitigated OA progression, and inhibited the RANKL reverse signaling pathway.

Conclusion

OC-ABs play a critical role in exacerbating OA by promoting subchondral bone remodeling via the RANKL reverse signaling pathway. Rapamycin presents as a promising therapeutic agent capable of mitigating OC-AB-driven pathology, highlighting new avenues for targeted OA treatment.

Disparities in Clinical and Experimental Pain Between Non-Hispanic White and Asian American Individuals With Knee Osteoarthritis and the Role of Pain Catastrophizing: Pilot Study in Florida

BACKGROUND

Although a few studies have delineated the disparities in knee osteoarthritis (KOA) pain between non-Hispanic White and Asian American individuals, a significant research gap persists in elucidating the mechanisms underlying these differences.

OBJECTIVE

This pilot study aims to examine psychological factors, specifically pain catastrophizing and negative affect, as potential explanatory mechanisms for these dissimilarities.

METHODS

A cross-sectional design was used. Forty community-dwelling participants aged 50-70 years with self-reported KOA pain, including 20 non-Hispanic White and 20 Asian American individuals, were recruited in North Central Florida. Clinical KOA pain intensity was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the 4 subscales of the Short-Form McGill Pain Questionnaire-2. Quantitative sensory testing was conducted to measure experimental sensitivity to heat- and mechanically induced pain, including heat pain, pressure pain threshold, and punctate mechanical pain, as well as inhibitory pain processes through conditioned pain modulation. Pain catastrophizing was evaluated using the Coping Strategies Questionnaire-Revised Pain Catastrophizing subscale, while negative affect was assessed using the Positive and Negative Affect Schedule. Bayesian mediation analyses were used to examine both direct and indirect effects (mediation) between variables.

RESULTS

Asian American individuals exhibited higher pain catastrophizing scores than non-Hispanic White individuals. Pain catastrophizing, at high levels, contributed to WOMAC and Short-Form McGill Pain Questionnaire-2, which measured clinical pain. Race had no direct effects on these pain scores but exerted significant indirect effects via pain catastrophizing (WOMAC pain: 0.96, 95% CI 0.03-2.16; continuous pain: 0.84, 95% CI 0.18-1.70; intermittent pain: 0.78, 95% CI 0.03-1.71; neuropathic pain: 0.43, 95% CI 0.03-0.95; and affective pain: 1.05, 95% CI 0.24-1.99); thus, pain catastrophizing likely fully mediated the relationship between race and these pain measures. While Asian American individuals reported greater experimental pain sensitivity (heat pain, pressure pain threshold, and punctate mechanical pain) than non-Hispanic White individuals, these racial effects were not mediated by pain catastrophizing. Asian American individuals reported higher negative affect scores compared with non-Hispanic White individuals; however, negative affect did not mediate the relationship between race and any pain measures.

CONCLUSIONS

 The results demonstrate the contribution of pain catastrophizing to clinical pain in Asian American individuals with KOA and identify it as a potential mechanism underlying group differences in KOA pain between non-Hispanic White and Asian American individuals. However, caution is warranted due to the exploratory nature of this study and the treatment of Asian American individuals as a monolithic sample. Hence, future replication with larger and more diverse samples is necessary. Additionally, the lack of mediation effects of pain catastrophizing in the relationship between race and experimental pain suggests the need to explore other factors, such as biological, genetic, social, and environmental influences. Moreover, further research is essential to clarify the role of negative affect.

MMP13 mRNA Expression Level as a Potential Marker for Knee OA Progression-An Observational Study

Background/Objectives: Osteoarthritis (OA) is a very common degenerative joint disease that has a significant negative impact on patients' lives and which can lead to functional limitations and disability. Matrix metalloproteinase 13 (MMP-13) is a key enzyme responsible for the degenerative changes in cartilage occurring during the pathogenesis of OA. This cohort study analyzed the differences in the expression level of MMP13 mRNA in articular cartilage with subchondral bone and in the synovium of patients with OA, according to the disease stage, in order to develop potential markers for OA progression, as well as for the degree of pain perception, in order to discover a molecular biomarker related to pain. Methods: In thirty-one patients (n = 31), the expression level of the studied gene was assessed in the affected and unaffected areas of the knee joint using the qPCR method. Statistical analysis was performed using the Mann-Whitney U test, the Kruskal-Wallis test, and Spearman's rank correlation coefficient. Results: A significantly higher expression level of MMP13 mRNA was noticed in the OA-affected articular cartilage with subchondral bone compared to the control tissue (p = 0.027, Mann-Whitney U test). The expression level of MMP13 mRNA was higher in patients with stage 4 knee OA than in those with stage 3, but the difference in MMP13 mRNA expression level was statistically insignificant (p > 0.05, Mann-Whitney U test). A higher MMP13 mRNA expression level was noticed in the OA-affected synovium compared to the control tissue (median RQ: 0.068 and 0.037, respectively), but these differences were not significant (p > 0.05, Mann-Whitney U test). A significantly higher MMP13 mRNA expression level was observed in the synovium of stage 4 knee OA patients compared to stage 3 patients (p = 0.015, Mann-Whitney U test). There was no significant difference in the expression level of MMP13 mRNA between both tissues, i.e., the articular cartilage with subchondral bone and the synovium from the stage 3 group and the control tissue (p > 0.05, Mann-Whitney U test); however, a significant difference was found between these tissues in stage 4 and in the control tissue (p = 0.014, Mann-Whitney U test). Conclusions: The results of our pilot study indicated the diagnostic potential of MMP13 mRNA and proved its role in the development and progression of OA. Further studies are needed to verify the potential utility of MMP13 mRNA in the development of molecularly targeted therapy for patients with OA.

The Interplay of Aging and PANoptosis in Osteoarthritis Pathogenesis: Implications for Novel Therapeutic Strategies

Osteoarthritis (OA) is a common degenerative joint disease characterized by the progressive degradation of articular cartilage, synovial inflammation, and subchondral bone remodeling. This review explores the interplay between aging, PANoptosis, and inflammation in OA progression. Age-related cellular and immune dysfunctions, including cellular senescence, senescence-associated secretory phenotypes (SASPs), and immunosenescence, significantly contribute to joint degeneration. In OA, dysregulated apoptosis, necroptosis, and pyroptosis, particularly in chondrocytes, exacerbate cartilage damage. Apoptosis, mediated by the JNK pathway, reduces chondrocyte density, while necroptosis and pyroptosis, involving RIPK-1/RIPK-3 and the NLRP3 inflammasome, respectively, amplify inflammation and cartilage destruction. Inflammatory cytokines and damage-associated molecular patterns (DAMPs) further enhance these PANoptotic pathways. Current therapeutic strategies primarily focus on anti-inflammatory agents such as non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids, with growing interest in anti-senescence drugs targeting cellular senescence and SASP. Additionally, exploring PANoptosis mechanisms offers potential for innovative OA treatments.

Transcriptomic insights into the anti-inflammatory mechanisms of Protaetia brevitarsis seulensis larvae in IL-1β-driven chondrosarcoma cells

Osteoarthritis (OA) is a complex, degenerative, multi-factorial joint disease. Because of the difficulty in treating OA, developing new targeting strategies that can be used to understand its molecular mechanisms is critical. Protaetia brevitarsis seulensis larvae offer much therapeutic value; however, the presence of various active compounds and the multi-factorial risk factors for OA render the precise mechanisms of action unclear. A systematic transcriptome analysis was used to investigate the key mechanisms of action of P. brevitarsis seulensis larvae aqueous extract (PBSL) and its compounds on OA. Major mechanisms and transcription factors of PBSL were analyzed by profiling gene expression changes in interleukin (IL)-1β-induced human chondrosarcoma cell (SW1353) treated with PBSL. An in vitro assay was performed to validate the efficacy of the novel mechanism and targets of PBSL. PBSL exerted anti-inflammatory effects on SW1353 cells by regulating many molecular pathways. The IL-6/JAK/STAT3 pathway was significantly downregulated by PBSL, and STAT3 was identified as a major transcription factor regulating PBSL-induced target gene expression. Of the six PBSL compounds, the major compound was regulated by the IL-6/JAK/STAT3 pathway. This study provided potential novel mechanisms and transcription factors for PBSL and its active compounds against OA and indicated that inhibiting the IL-6/JAK/STAT3 pathway is a therapeutic target for treating OA.

Association between medial meniscal extrusion and knee structural progression in adults with symptomatic knee osteoarthritis - a prospective cohort study

OBJECTIVE

To examine the association between medial meniscal extrusion and structural progression in adults with symptomatic knee osteoarthritis (OA).

METHODS

This prospective cohort study examined 176 participants with symptomatic knee OA recruited into a randomised controlled trial. The participants underwent magnetic resonance imaging (MRI) of the study knee at baseline and approximately 2 years later. Meniscal extrusion, tibial cartilage volume, and tibiofemoral bone marrow lesions (BMLs) were measured from MRI using validated methods.

RESULTS

Participants with medial meniscal extrusion ≥ 3 mm had a higher prevalence of lateral tibiofemoral BMLs at baseline (OR = 2.21, 95% CI 1.06-4.61, p = 0.035), and those with medial meniscal extrusion 2-3 mm had a higher likelihood of lateral BML worsening over 2 years (OR = 3.76, 95% CI 1.35-10.52, p = 0.011), compared with those with medial meniscal extrusion < 2 mm. Participants with stable medial meniscal extrusion had a lower likelihood of lateral BML worsening compared with those with regression of medial meniscal extrusion over 2 years (OR = 0.20, 95% CI 0.07-0.56, p = 0.002). There were no associations between medial meniscal extrusion and tibial cartilage volume or medial tibiofemoral BMLs.

CONCLUSIONS

Our study showed associations between medial meniscal extrusion and baseline prevalence and worsening over 2 years of lateral tibiofemoral BMLs in people with symptomatic knee OA. Although the reasons for the lack of associations in the medial compartment are not clear, our results suggest a role of medial meniscal extrusion in predicting structural progression in lateral knee OA and that meniscal extrusion might be a potential target in the management of knee OA.

BMSC Derived Exosomes Attenuate Apoptosis of Temporomandibular Joint Disc Chondrocytes in TMJOA via PI3K/AKT Pathway

Bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) are crucial means of intercellular communication and can regulate a range of biological processes by reducing inflammation, decreasing apoptosis and promoting tissue repair. We treated temporomandibular joint (TMJ) disc chondrocytes with TNF-α and performed local injection of sodium iodoacetate (MIA) in the TMJ of rats to establish in vitro and in vivo models of TMJ osteoarthritis (TMJOA). BMSC-Exos were isolated and extracted to evaluate their proliferation and trilineage differentiation abilities, and their antiapoptotic and chondroprotective effects were assessed. This study revealed that BMSC-Exos can be endocytosed by TMJ disc chondrocytes in vitro and that BMSC-Exos pretreatment strongly attenuated the inhibitory effect of TNF-α on the proliferative and chondrogenic potential of TMJ disc chondrocytes. The administration of BMSC-Exos significantly suppressed TNF-α-induced apoptosis in TMJ disc chondrocytes by increasing the phosphorylation level of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT) pathway-related proteins, whereas the PI3K inhibitor LY294002 neutralized this antiapoptotic effect. Intradiscal injection of BMSC-Exos alleviated the degeneration and inflammation of TMJ discs in a rat model of TMJOA. Our study revealed that BMSC-Exos can attenuate the apoptosis of TMJ disc chondrocytes and destruction of TMJ discs partially by inhibiting the apoptotic pathway and activating the PI3K/AKT pathway, thereby providing a promising treatment strategy for the regeneration of damaged TMJ discs.

The causal impact of smoking behavior on osteoarthritis: a Mendelian randomization analysis

Objective

Although smoking and osteoarthritis (OA) have been linked in a number of studies, the exact cause of the association is still unknown and the conclusion is controversial. The purpose of this study was to use Mendelian randomization (MR) analysis to investigate the causal relationship between smoking phenotypes and OA risk from a genetically informed standpoint.

Methods

As instrumental variables (IVs) based on single nucleotide polymorphisms (SNPs), this study used the summary-level data of corresponding genome-wide association study (GWAS) for five smoking phenotypes involving 1,694,781 samples. The outcomes comprised both a discovery and a replication cohort. The discovery MR analysis involved 12 OA traits (177,517 cases and 649,173 controls) while the replication MR analysis incorporated an additional OA GWAS dataset consisting of 36,185 cases and 135,185 controls. The main analytic approach we used was the inverse variance weighted (IVW) method. MR Egger, Weighted median, Weighted mode, and Simple mode were among the other methods that were tested. We conducted meta-analysis to combine the MR results. To confirm the robustness of the results, sensitivity analysis using Leave-One-Out (LOO), level pleiotropy testing (MR Egger intercept test and MR-PRESSO), and heterogeneity testing were performed.

Results

Summary-level MR analysis revealed a positive correlation between genetic predisposition for smoking and the likelihood of developing OA. The meta-analysis merge showed that smoking initiation increased the risk of knee OA by 20%, hip OA by 16%, and knee/hip OA by 19% (all p < 0.001). Similarly, lifetime smoking elevated the risk of knee OA by 101%, hip OA by 55%, and knee/hip OA by 84% (all p < 0.001). The sensitivity analysis's findings reinforced the reliability of these findings.

Conclusion

According to our research, smoking increases the likelihood of developing OA from a genetic standpoint. Reducing tobacco use could, therefore, be beneficial in lowering the incidence of OA.

Viral infections of the central nervous system increase the risk of knee osteoarthritis: a two-sample mendelian randomization study

OBJECTIVE

Osteoarthritis (OA) represents a condition under the influence of central nervous system (CNS) regulatory mechanisms. This investigation aims to examine the causal association between viral infections of the central nervous system (VICNS) and inflammatory diseases of the central nervous system (IDCNS) and knee osteoarthritis (KOA) at the genetic level.

METHODS

In this investigation, VICNS and IDCNS were considered as primary exposure variables, while KOA served as the primary outcome. Employing a two-sample mendelian randomization (MR) approach, we conducted an analysis utilizing summary data derived from genome-wide association studies (GWAS). The GWAS summary data pertaining to VICNS and IDCNS were procured from the Finnish consortium, whereas the IEU OpenGWAS database furnished the requisite data for KOA. To ensure the robustness of our genetic causal assessment, a comprehensive array of sensitivity analyses was undertaken, encompassing evaluations of heterogeneity, horizontal pleiotropy, outlier identification, leave-one-out analyses, and assessment of the normal distribution.

RESULTS

The results of the MR analyses revealed a suggestive positive genetic causal relationship between VICNS and KOA (P = 0.012, odds ratio [OR] with a 95% confidence interval [CI] of 1.033 [1.007-1.059]). Conversely, the MR analyses did not indicate any evidence of genetic causation between IDCNS and KOA (P = 0.575, OR 95% CI = 0.986 [0.940-1.035]). Importantly, the genetic causal assessment of the exposure and outcome variables did not demonstrate any indications of heterogeneity, horizontal pleiotropy, or outliers. Furthermore, this assessment remained robust against the influence of individual single nucleotide polymorphisms (SNPs) and exhibited adherence to a normal distribution.

CONCLUSION

The result of this study has elucidated a suggestive positive genetic causal link between the VICNS and KOA. However, no such genetic causal relationship was observed between the IDCNS and KOA. These findings substantiate the genetic underpinnings supporting the association between the CNS and OA.

Current status of nanofat in the management of knee osteoarthritis: A systematic review

BACKGROUND

Osteoarthritis (OA) is a prevalent joint disorder requiring innovative treatment approaches.

AIM

To evaluate the use of nanofat, a specialized form of adipose tissue-derived cells, in the treatment of OA, by examining its efficacy, safety profile, mechanisms of action, comparative effectiveness, and long-term outcomes.

METHODS

A comprehensive review of preclinical studies, clinical trials, and in vitro investigations was conducted. The included studies provided insights into the potential role of nanofat in OA treatment, addressing its efficacy, safety profile, mechanisms of action, comparative effectiveness, and long-term outcomes.

RESULTS

Clinical studies consistently reported the efficacy of nanofat in providing pain relief and functional improvement in patients with OA. Local adverse events were limited to the injection site, such as localized pain and inflammation, and resolved within a few days to weeks. Systemic adverse events were rare, and no significant long-term complications were observed. Mechanistically, nanofat was found to enhance chondrocyte proliferation, reduce inflammation, and promote angiogenesis, thereby contributing to its therapeutic effects.

CONCLUSION

Nanofat therapy holds promise as a therapeutic option for managing OA, providing pain relief, functional improvement, and potential tissue regeneration. The safety profile of nanofat treatment appears favorable, but long-term data are still limited. Standardized protocols, larger randomized controlled trials, longer follow-up periods, and cost-effectiveness evaluations are warranted to establish optimal protocols, comparative effectiveness, and long-term outcomes. Despite current limitations, nanofat therapy demonstrates translational potential and should be considered in clinical practice for OA treatment, with careful patient selection and monitoring.

Investigating the Potential of Magnesium Microparticles on Cartilage and Bone Regeneration Utilizing an In Vitro Osteoarthritis Model

Osteoarthritis (OA) is a significant condition that profoundly impacts synovial joints, including cartilage and subchondral bone plate. Biomaterials that can impede OA progression are a promising alternative or supplement to anti-inflammatory and surgical interventions. Magnesium (Mg) alloys known for bone regeneration potential were assessed in the form of Mg microparticles regarding their impact on tissue regeneration and prevention of OA progression. In vitro assays based on mesenchymal stem cells (SCP-1) were applied to evaluate the Mg microparticle's compatibility and function. Biocompatibility documented through live-dead staining and lactate dehydrogenase assay revealed a 90% cell viability at a concentration below 10 mM after 3 days of exposure. An in vitro OA model based on the supplementation of the cytokines IL-1β, and TNF-α was established and disclosed the effect of Mg degradation products in differentiating SCP-1 cells. Sustained differentiation was confirmed through extracellular matrix staining and increased gene marker expression. The Mg supplementation reduced the release of inflammatory cytokines (IL-6 and IL-8) while promoting the expression of proteins such as collagen X, collagen I, and osteopontin in a time-dependent manner. The in vitro study suggests that Mg microparticles hold a therapeutic potential for OA treatment with their ability to support bone and cartilage repair mechanisms even under inflammatory conditions.

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

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

Musculoskeletal Organs-on-Chips: An Emerging Platform for Studying the Nanotechnology-Biology Interface

Nanotechnology-based approaches are promising for the treatment of musculoskeletal (MSK) disorders, which present significant clinical burdens and challenges, but their clinical translation requires a deep understanding of the complex interplay between nanotechnology and MSK biology. Organ-on-a-chip (OoC) systems have emerged as an innovative and versatile microphysiological platform to replicate the dynamics of tissue microenvironment for studying nanotechnology-biology interactions. This review first covers recent advances and applications of MSK OoCs and their ability to mimic the biophysical and biochemical stimuli encountered by MSK tissues. Next, by integrating nanotechnology into MSK OoCs, cellular responses and tissue behaviors may be investigated by precisely controlling and manipulating the nanoscale environment. Analysis of MSK disease mechanisms, particularly bone, joint, and muscle tissue degeneration, and drug screening and development of personalized medicine may be greatly facilitated using MSK OoCs. Finally, future challenges and directions are outlined for the field, including advanced sensing technologies, integration of immune-active components, and enhancement of biomimetic functionality. By highlighting the emerging applications of MSK OoCs, this review aims to advance the understanding of the intricate nanotechnology-MSK biology interface and its significance in MSK disease management, and the development of innovative and personalized therapeutic and interventional strategies.

Therapeutic Efficacy of Medicinal Plants with Allopathic Medicine in Musculoskeletal Diseases

Musculoskeletal diseases encompass a diverse array of disorders affecting the muscles, bones, joints, and connective tissues, leading to significant impairments in mobility, function, and quality of life. Affecting over 1.3 billion individuals globally, musculoskeletal diseases represent a major source of disability and economic burden. Conventional treatment modalities, including pharmacological interventions and surgical procedures, are frequently limited by adverse side effects, prolonged recovery periods, and patient dissatisfaction, particularly when focused solely on symptom management. In response, complementary and alternative medicine, particularly the use of medicinal plants, has garnered increasing interest to enhance the management of musculoskeletal diseases. Medicinal plants possess a wide spectrum of pharmacologically active compounds with anti-inflammatory, analgesic, and antioxidant properties, making them promising adjuncts to conventional therapies. This review critically evaluates the potential synergy between medicinal plants and allopathic medicine for the management of musculoskeletal diseases, with an emphasis on integrated therapy that combines both modalities. Specifically, a critical discussion is presented on how medicinal plants with scientifically supported pharmacological properties can augment the therapeutic efficacy of conventional medications, reduce their doses, and mitigate adverse effects. Furthermore, the challenges associated with incorporating herbal medicine into established healthcare systems are discussed, including the need for rigorous clinical validation, standardization, and regulatory frameworks. Overall, the article underscores the potential of integrated therapeutic approaches to improve clinical outcomes, enhance patient well-being, and establish a more sustainable model for the treatment of musculoskeletal diseases.

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

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

Innovative Approaches in Knee Osteoarthritis Treatment: A Comprehensive Review of Bone Marrow-Derived Products

Knee osteoarthritis (OA) is a chronic articular disease characterized by the progressive degeneration of cartilage and bone tissue, leading to the appearance of subchondral cysts, osteophyte formation, and synovial inflammation. Conventional treatments consist of non-steroidal anti-inflammatory drugs (NSAIDs), analgesics, and glucocorticoids. However, the prolonged use of these drugs causes adverse effects. NSAIDs, for instance, are known to be nephrotoxic, increasing the damage to articular cartilage. New therapies capable of accelerating the process of tissue regeneration and repair are being discussed, such as the use of orthobiologics that are naturally found in the body and obtained through minimally invasive collection and/or laboratory manipulations. Bone marrow aspirate (BMA) and bone marrow aspirate concentrate (BMAC) are both rich in hematopoietic stem cells, mesenchymal stem cells (MSCs), and growth factors (GFs) that can be used in the healing process due to their anabolic and anti-inflammatory effects. The aim of this literature review is to assess the efficacy of BMA and BMAC in the treatment of knee OA based on the favorable results that researchers have obtained with the use of both orthobiologics envisaging an accelerated healing process and the prevention of OA progression.

Activation of cannabinoid receptor 2 by turmeric oleoresin reduces inflammation and oxidative stress in an osteoarthritis in vitro model

Introduction

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by the progressive degradation of articular cartilage, resulting in pain and reduced mobility. Turmeric (Curcuma longa L.) has been widely recognized for its anti-inflammatory and antioxidant properties, but the molecular mechanisms underlying its therapeutic effects remain inadequately explored. This study investigates the potential of turmeric oleoresin (TUR) to activate Cannabinoid Receptor 2 (CBR2) and its role in mediating anti-inflammatory and antioxidant effects in an in vitro OA model.

Material and methods

Molecular docking and cAMP quantification assays were used to evaluate TUR's agonistic activity on CBR2. Human chondrosarcoma cells (SW-1353) were treated with TUR under oxidative stress induced by menadione or inflammatory conditions simulated with IL-1β and TNF-α. The effects of TUR were assessed in the presence and absence of the CBR2 antagonist SR144528. Outcomes included changes in reactive oxygen species (ROS) production, inflammatory marker expression, oxidative defense markers and endocannabinoid system components and receptors.

Results

TUR was confirmed as a CBR2 agonist and significantly reduced ROS production, downregulated pro-inflammatory cytokines (IL-6, COX-2, metalloproteases), and suppressed signaling pathways such as NFKB1, ERK 1/2, and c-Myc. These effects were reversed upon CBR2 inhibition. TUR also enhanced HMOX-1 expression and modulated endocannabinoid-related enzymes, highlighting its impact on oxidative stress and the endocannabinoid system.

Discussion

These findings suggest that CBR2 activation is central to TUR's anti-inflammatory and antioxidant effects. By modulating key pathways and endocannabinoid system components, TUR demonstrates potential as a novel therapeutic agent for OA management. Future studies could explore its clinical applications and further validate its molecular mechanisms in vivo.

Effect of total knee arthroplasty on quadriceps and hamstring muscle recovery in individuals with knee osteoarthritis: A proposed systematic review and meta-analysis protocol

Knee osteoarthritis is a prevalent degenerative joint disease leading to pain, stiffness, reduced mobility in the knee, and muscle weakness. Total knee arthroplasty (TKA) is typically the preferred surgical treatment option for moderate to severe osteoarthritis. A deeper understanding of quadriceps and hamstring muscle activation after TKA is needed to monitor patient prognosis postoperatively. This review aims to synthesize and summarize the available evidence on the effects of TKA on quadriceps and hamstring muscle recovery in individuals with knee osteoarthritis. Electronic databases such as PubMed, Scopus, Web of Science, CINAHL, EMBASE, and ProQuest Health & Medical Complete will be searched using relevant keywords related to knee osteoarthritis, total knee arthroplasty, surface electromyography and quadriceps and hamstring muscle recovery. Two reviewers will independently assess the related studies and extract data from the chosen articles. The Cochrane Risk of Bias Tool-1 and the Joanna Briggs critical appraisal checklist will be used to assess the methodological quality of the studies based on study design. Based on the relevance of the data and number of studies, a meta-analysis approach will be used to obtain a unified outcome. This review's findings will support clinical decision-making and offer direction for future researchers studying this patient population. Bullet points that outline the protocol•This proposed systematic review, and meta-analysis will summarize and synthesize literature on the effect of total knee arthroplasty (TKA) on quadriceps and hamstring muscle recovery in individuals with knee osteoarthritis.•This review offers important insights into knee muscle recovery following TKA, assisting orthopedic surgeons and rehabilitation professionals in improving their clinical decision-making.

Correlation of Detachment of Proximal Tibia Superficial Medial Collateral Ligament and Medial Meniscus Extrusion with Knee Osteoarthritis

Introduction

The aim of the study is to assess the correlation of detachment of proximal tibia superficial medial collateral ligament (sMCL) and medial meniscus (MM) extrusion with knee osteoarthritis (OA) and its progression.

Materials and Methods

This is a prospective study where 165 knees were evaluated using radiographs and magnetic resonance imaging for the severity of OA knee according to Kellgrence-Lawrence grading, MM extrusion, and status of proximal tibia attachment of sMCL. Chi-square test of Independence and Pearson's correlation test were used to assess any correlation among the variables.

Results

The study population had a mean age of 52.93 ± 19.46 years. 106 (64.24%) were males and 59 (35.75 were females. There were 83 (50.30%) left knees and 82 (49.70%) right knees in the study. The percentage of proximal tibia sMCL detachment was more in patients with knee OA than those without OA (85-88.89%). Similarly, the percentage of MM extrusion was maximum in advanced arthritis patients (95%). Both these variables were lowest in non-arthritic group (2.56% and 6.41%, respectively). Statistical analysis showed a significantly positive correlation of detachment of proximal tibial attachment of sMCL as well as MM extrusion with grades of OA of knee (P < 0.001 for both).

Conclusion

A detached proximal tibia sMCL and an extruded MM were individually found to have a strong association (Chi-square test) and a positive linear correlation (Pearson's test) with the arthritic condition of the knee. This would suggest a role of both these variables in the progression of knee OA. They can thus be used as prognostic markers for knee OA as well as an important target in the management of knee OA.

Obesity-induced fibrosis in osteoarthritis: Pathogenesis, consequences and novel therapeutic opportunities

Osteoarthritis (OA) is a significant global burden, affecting more than half a billion people across the world. It is characterized by degeneration and loss of articular cartilage, synovial inflammation, and subchondral bone sclerosis, leading to pain and functional impairment. After age, obesity is a major modifiable risk factor for OA, and it has recently been identified as a chronic disease by the World Health Organization (WHO). Obesity is associated with high morbidity and mortality, imposing a significant cost on individuals and society. Obesity increases the risk of knee OA through increased joint loading, altered body composition, and elevated pro-inflammatory adipokines in the systemic circulation. Moreover, obesity triggers fibrotic processes in different organs and tissues, including those involved in OA. Fibrosis in OA refers to the abnormal accumulation of fibrous tissue within and around the joints. It can be driven by increased adiposity, low-grade inflammation, oxidative stress, and metabolic alterations. However, the clinical outcomes of fibrosis in OA are unclear. This review focuses on the link between obesity and OA, explores the mechanism of obesity-driven fibrosis, and examines potential therapeutic opportunities for targeting fibrotic processes in OA.

Prevalence and risk factors of osteoarthritis in patients at a public hospital in Limpopo province

BACKGROUND

Osteoarthritis (OA) is a public health concern affecting millions globally. Osteoarthritis has been ranked as the 12th leading cause of disability among the ageing population globally. In addition, OA can lead to disability, which can affect the quality of life and physical and emotional well-being.

METHODS

A cross-sectional survey was conducted. An interviewer-administered questionnaire was utilised. Logistic regression was used to identify OA-related factors in the univariable and multivariable models. A p-value less than 0.05 was deemed statistically significant.

RESULTS

A total of 210 participants responded to the questionnaire. The overall prevalence of OA at the public hospital was 55.7% in adults over 18 years willing to participate. Among the study participants, females, individuals over the age of 50 years, and obese patients reported a high prevalence of OA. Family history and knee and hip pain were significantly associated with OA (p  0.05). Participants with a family history of OA were 6.9 times more likely to have OA, those with knee pain were 22.8 times more likely and those with hip pain were 5.5 times more likely after adjusting for the other variables.

CONCLUSION

A high proportion of patients reported to have OA. Family history, knee pain and hip pain were strongly associated with OA. Understanding the prevalence and risk factors associated with OA is crucial for developing targeted interventions for prevention and management.Contribution: Targeted health promotion and education interventions are needed for prevention and early management.

Mitoregulin modulates inflammation in osteoarthritis: Insights from synovial transcriptomics and cellular studies

Osteoarthritis is a prevalent musculoskeletal disease that involves cartilage degradation, subchondral bone remodeling, and synovial inflammation and ultimately causes physical disability. Common risk factors for osteoarthritis include age, sex, obesity, and genetic predispositions. Treatment includes nonpharmaceutical and pharmacological approaches; however, disease-modifying osteoarthritis drugs remain undeveloped. We aimed to identify key regulatory factors underlying the etiology of osteoarthritis. We studied alterations of the inflammatory responses after manipulating the expression of MTLN, which we selected after sequencing and transcriptomics of the patients' synovial tissues. MTLN expression was increased in synovial tissues of patients and in SW982 human synovial sarcoma cells following inflammatory stimuli. We found that MTLN overexpression or knockout respectively decreased or increased expression of the inflammation-associated genes, including IL-6, IL-8, and TNF-α. Thus, high levels of MTLN in osteoarthritis may protect tissues against excessive inflammation, thereby offering therapeutic potentials.

UBE2I regulates the nuclear translocation of hnRNPA2B1 by contributing to SUMO modification in osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a progressive condition affecting the joints that lacking effective therapy. However, the underlying molecular mechanism has not been fully clarified.

METHODS

A model of OA was established in Sprague-Dawley (SD) rats through intra-articularly injected with monoiodoacetate (MIA). Western blot analysis was used to identify the levels of UBE2I and hnRNPA2B1 in articular cartilage. Overexpression and siRNA vectors for UBE2I were constructed and transfected into rat chondrocytes. CCK-8, TUNEL and transwell assay were utilized to assess the cell viability, apoptosis and migration ability. Western blot analysis was used to determine the levels of chondrogenic-specific genes including SOX9, COL2A1, Aggrecan, and PRG4. Then, molecular interactions were confirmed by immunoprecipitation.

RESULTS

We observed significant upregulation of UBE2I and hnRNPA2B1 expression in articular cartilage samples of OA. The Pearson correlation analysis revealed positive correlation between UBE2I and hnRNPA2B1 levels. Functional experiments showed that increased UBE2I expression significantly suppressed cell growth, migration, and reduced the expression of chondrogenic-specific genes, while decreasing UBE2I levels had the opposite effects. Molecular interactions between UBE2I and hnRNPA2B1were determined via co-localization and immunoprecipitation. SUMO1 and SUMO3 proteins were enriched by immunoprecipitation using hnRNPA2B1 antibodies. Rescue experiments were performed using SUMOylation inhibitor (2-D08) and SUMOylation activator (N106). Overexpression of UBE2I increased the expression of hnRNPA2B1 in the cytoplasm and decreased the level in the nucleus, which was reversed by the treatment of 2-D08. Conversely, UBE2I knockdown and N106 treatment had the opposite effect.

CONCLUSIONS

UBE2I modulated the nuclear translocation of hnRNPA2B1 by promoting SUMOylation in OA.

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

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

From polarity to pathology: Decoding the role of cell orientation in osteoarthritis

Cell polarity refers to the orientation of tissue and organelles within a cell and the direction of its function. It is one of the most critical characteristics of metazoans. The development, growth, and functional tissue distribution are closely related to holistic tissue or organ homeostasis. However, the connection between cell polarity and osteoarthritis (OA) is less well-known. In OA, multiple chondrocyte clusters and tissue disorganisation can be observed in the degraded cartilage tissue. The excessive upregulation of the planar cell polarity (PCP) signalling pathway leads to the loss of cell polarity and organisation in OA progression and aetiology. Recent research has become increasingly aware of the importance of cell polarity and its correlation with OA. Several cell polarity-related treatments have shed light on OA. A thorough understanding of cell polarity and OA would provide more insights for future investigations to treat this worldwide disease.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Understanding cell polarity, associated signalling pathways, organelle changes, and cell movement in the development of OA could lead to advances in precision medicine and enhanced treatment strategies for OA patients.

Emerging role and function of Hippo-YAP/TAZ signaling pathway in musculoskeletal disorders

Hippo pathway is an evolutionarily conservative key pathway that regulates organ size and tissue regeneration by regulating cell proliferation, differentiation and apoptosis. Yes-associated protein 1 (YAP)/ WW domain-containing transcription regulator 1 (TAZ) serves as a pivotal transcription factor within the Hippo signaling pathway, which undergoes negative regulation by the Hippo pathway. The expression of YAP/TAZ affects various biological processes, including differentiation of osteoblasts (OB) and osteoclasts (OC), cartilage homeostasis, skeletal muscle development, regeneration and quality maintenance. At the same time, the dysregulation of the Hippo pathway can concurrently contribute to the development of various musculoskeletal disorders, including bone tumors, osteoporosis (OP), osteoarthritis (OA), intervertebral disc degeneration (IDD), muscular dystrophy, and rhabdomyosarcoma (RMS). Therefore, targeting the Hippo pathway has emerged as a promising therapeutic strategy for the treatment of musculoskeletal disorders. The focus of this review is to elucidate the mechanisms by which the Hippo pathway maintains homeostasis in bone, cartilage, and skeletal muscle, while also providing a comprehensive summary of the pivotal role played by core components of this pathway in musculoskeletal diseases. The efficacy and feasibility of Hippo pathway-related drugs for targeted therapy of musculoskeletal diseases are also discussed in our study. These endeavors offer novel insights into the application of Hippo signaling in musculoskeletal disorders, providing effective therapeutic targets and potential drug candidates for treating such conditions.

Comparative Analysis of Osteoarthritis Therapeutics: A Justification for Harnessing Retrospective Strategies via an Inverted Pyramid Model Approach

In this review, we seek to explore two distinct approaches to the clinical management of OA: a prospective approach, addressing primarily one's genetic predisposition to OA and generating early intervention options, and the retrospective approach, aimed at halting or reversing OA progression post-symptom onset. The clinical management of OA remains challenging, largely due to the limited availability of preventative treatments and failure of existing therapies to modify or reverse the underlying pathophysiology. The prospective approach involves the identification of genetic markers associated with OA and utilizes in vitro and in vivo models to characterize the underlying disease mechanism. Further, this approach focuses on identifying genetic predispositions and unique molecular subtypes of OA to develop individualized treatment plans based on patient genotypes. While the current literature investigating this strategy has been notable, this approach faces substantial challenges, such as extensive time burdens and utilization of extensive genetic testing that may not be economically feasible. Additionally, there is questionable justification for such extensive investigations, given OA's relatively low mortality rates and burden when contrasted with diseases like specific forms of cancer, which rely heavily on the prospective approach. Alternatively, the retrospective approach primarily focuses on intervention following symptom onset and aims to utilize novel therapeutics to slow or reverse the inflammatory cascade typically seen in disease progression. These treatments, like Hippo pathway inhibitors, have shown initial promise in halting OA progression and alleviating OA symptomology by modulating cellular processes to preserve articular cartilage. In comparison to the prospective approach, the retrospective strategy is likely more cost-effective, more widely applicable, and does not necessitate thorough and invasive genetic screening. However, this approach must still be weighed against the typical natural history of disease progression, which frequently results in total knee arthroplasty and unacceptable outcomes for 15-20% of patients. From a comparative analysis of these two approaches, this review argues that the retrospective strategy, with ideally lower time and economic burden and greater accessibility, offers a more reasonable and effective solution in the context of OA management. Using a similar approach to other management of chronic diseases, we suggest an "Inverted Pyramid" model algorithm, a structured research and development regimen that prioritizes generating widely effective therapies first, with subsequent refinement of treatments based on the development of patient resistance to these therapies. We argue that this strategy may reduce the need for total knee arthroplasty while improving patient outcomes and accessibility.

Advancing Osteoarthritis Treatment: The Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes and Biomaterial Integration

BACKGROUND/OBJECTIVES

Osteoarthritis (OA) is a prevalent and debilitating joint disorder characterized by progressive cartilage degradation and inflammation, for which traditional treatments offer only symptomatic relief without halting disease progression. Exosomes, cell-free vesicles derived from mesenchymal stem cells, have emerged as a promising alternative therapy owing to their regenerative and anti-inflammatory properties.

METHODS

This review synthesizes findings from recent studies (2017-2023) on the therapeutic potential of exosomes in OA treatment, highlighting their ability to modulate the joint microenvironment, reduce inflammation, and promote cartilage repair by delivering bioactive molecules such as cytokines, growth factors, and regulatory ribonucleic acids.

RESULTS

We explore the integration of exosomes with biomaterials, such as hydrogels and scaffolds, to enhance their delivery and therapeutic efficacy, and we address the critical challenges associated with their clinical application, including standardization of isolation and characterization methods, scalability of production, mechanistic understanding, and long-term safety. Despite these challenges, exosome-based therapies offer several advantages over traditional and cell-based treatments, including lower immunogenicity, ease of handling, and targeted delivery of therapeutic agents to damaged tissues.

CONCLUSIONS

We provide an analytical perspective on the current state of exosome research in OA, emphasizing the need for standardized production methods, deeper mechanistic insights, and rigorous long-term safety assessments. Future directions should focus on optimizing delivery systems, exploring personalized medicine approaches, and conducting comparative effectiveness studies to fully realize the potential of exosome therapies for OA treatment. Addressing these gaps will be crucial for translating exosome therapies from bench to bedside and achieving a transformative impact on OA management.

Investigation of the analgesic efficacy of local therapy with non-steroidal anti-inflammatory drugs in patients with knee osteoarthritis

Objective: to analyze the extent of analgesic effect and to determine predictors of inadequate response to local therapy with non-steroidal antiinflammatory drugs (NSAIDs) in a prospective, comparative, randomized trial of the efficacy and safety of Artoxan® gel 1% versus Diclofenac gel 1% in patients with knee OA.

Material and methods. The study included 60 patients with a definite diagnosis of stage II–III Kеllgren–Lawrence knee OA who fulfilled ACR criteria and were observed on an outpatient basis in V.A. Nasonova Research Institute of Rheumatology. Patients were 40–80 years old (mean 62.50±8.04 years), body mass index (BMI) 24.9±4.67 kg/m2 , median OA duration 5.7 [3;15] years. According to the randomization scheme, the patients were divided into two groups. In the 1st group (n=30), local therapy with 1% Artoxan gel was applied to the target area of the knee twice daily for 14 days. Patients in the 2nd group (n=30) were prescribed local therapy with the comparator drug, 1% Diclofenac gel with a similar application regimen. Patients in both groups were comparable in terms of the main parameters.

Results and discussion. Patients in both groups showed a significant decrease in pain intensity in the target joint during walking according to the visual analogue scale (VAS) after two weeks of treatment (p <0.05). A decrease in pain (to mild or moderate) in the target joint to <40 mm according to VAS after 7 days of therapy reported 43.3% of patients in the 1st group, and 63.3% of patients after 14 days of therapy (p=0.09). In the 2nd group, 43.3 % of patients also reported a reduction in pain in the target joint to <40 mm according to VAS after 7 days of therapy, and after 14 days it was observed in 56.7% of cases (p=0.22). Although the differences between the groups did not reach statistical significance, a reduction in pain to <40 mm according to VAS and a high BMI (r= -0.28; p=0.029).

Conclusion. The results of the study demonstrate a significant analgesic effect of local NSAIDs in knee OA. In most patients, pain was <40 mm according to VAS after 2 weeks of local NSAID therapy. At the same time, there was a tendency towards a higher frequency of pain reduction to <40 mm according to VAS in the group receiving local therapy with 1% Artoxan gel. It was concluded that excessive body weight and high BMI may be predictors of inadequate analgesic effect in patients with knee OA.

The Pathogenetic Role of RANK/RANKL/OPG Signaling in Osteoarthritis and Related Targeted Therapies

Background: Osteoarthritis (OA) is the most common degenerative joint disease and affects millions of people worldwide, particularly the elderly population. The pathophysiology of OA is complex and involves multiple factors. Methods: Several studies have emphasized the crucial role of inflammation in this process. The receptor activator of NF-κB ligand (RANKL), the receptor activator of NF-κB (RANK), and osteoprotegerin (OPG) trigger a signaling cascade that leads to the excessive production of RANKL in the serum. Conclusions: The aim of this narrative review is (i) to assess the role of the RANK/RANKL/OPG signaling pathway in the context of OA progression, focusing especially on the physiopathology and on all the mechanisms leading to the activation of the inflammatory cascade, and (ii) to evaluate all the potential therapeutic strategies currently available that restore balance to bone formation and resorption, reducing structural abnormalities and relieving pain in patients with OA.

Harnessing the Power of Water: A Scoping Review of Hydrokinesiotherapy as a Game-Changer in Knee Osteoarthritis Management

Background: Knee osteoarthritis (OA) is a prevalent condition that significantly impairs pain, mobility, and quality of life. Hydrokinesiotherapy, a water-based exercise therapy, is gaining traction as a potential alternative to traditional land-based rehabilitation for managing knee OA symptoms. Methods: This scoping review aimed to evaluate the effectiveness of hydrokinesiotherapy compared to standard land-based physical therapy and self-administered exercise regimens in improving pain, joint mobility, quality of life, and physical function in patients with knee OA. Five randomized controlled trials (RCTs) were included, assessing outcomes using measures such as the WOMAC score, Visual Analog Scale (VAS), and SF-12. The studies were critically appraised using the PEDro scale and the RoB-2 tool to determine the quality and risk of bias. Results: Hydrokinesiotherapy consistently demonstrated superior outcomes in pain reduction, joint mobility, and physical function across all studies. Patients in the hydrokinesiotherapy groups reported significant improvements in pain and mobility, which were strongly associated with enhanced quality of life. The review also highlighted the potential for hydrokinesiotherapy to serve as an effective alternative or complement to land-based exercises, particularly in populations experiencing severe symptoms. Conclusions: Hydrokinesiotherapy is an effective intervention for managing knee OA, offering significant improvements in key clinical outcomes. Given its benefits, hydrokinesiotherapy should be considered a valuable addition to knee OA treatment protocols. However, further research is needed to confirm long-term effects and to explore ways to improve accessibility to this therapeutic option.

Efficacy of Platelet-Rich Plasma Intra-articular Injections in Hip and Knee Osteoarthritis

Osteoarthritis (OA) is a chronic degenerative disorder that causes significant pain and functional limitations. Platelet-rich plasma (PRP) therapy has gained considerable attention in recent years in the treatment of musculoskeletal injuries. In this narrative review, we aim to investigate the role of intra-articular PRP injections in the treatment of knee and hip OA. The review also discusses different classifications of PRP based on composition. Furthermore, this narrative review also identified various limitations of PRP therapy in OA. PRP is classified into different types based on cell content and fibrin architecture, including pure platelet-rich plasma (P-PRP), leukocyte- and platelet-rich plasma (L-PRP), pure platelet-rich fibrin (P-PRF), and leukocyte- and platelet-rich fibrin (L-PRF). Various clinical trials have shown that PRP is an effective option for the treatment of knee and hip OA. However, the superiority of PRP over hyaluronic acid has been reported inconsistently. This variability can be attributed to PRP preparation techniques. The safety profiles of PRP are generally favorable and the adverse effects are generally mild in nature. Although there is sufficient evidence in support of PRP in the treatment of OA, the long-term effects of PRP have not been reported. Further studies should focus on longer follow-up periods to identify the efficacy and safety of PRP in treating knee OA. There is also a need for standardization of PRP preparations in OA management.

TNFα-Induced Inflammation Model-Evaluation of Concentration and Passage-Dependent Effects on Bovine Chondrocytes

Inflammation models are widely used in the in vitro investigation of new therapeutic approaches for osteoarthritis. TNFα (tumor necrosis factor alpha) plays an important role in the inflammatory process. Current inflammation models lack uniformity and make comparisons difficult. Therefore, this study aimed to systematically investigate whether the effects of TNFα are concentration-dependent and whether chondrocyte expansion has an effect on the inflammatory model. Bovine chondrocytes were enzymatically isolated, expanded to passages 1-3, and transferred into a 3D pellet culture. Chondrocyte pellets were stimulated with recombinant bovine TNFα at different concentrations for 48 h to induce inflammation. Gene expression of anabolic (collagen 2, aggrecan, cartilage oligomeric protein (COMP)), catabolic (matrix metalloproteinases (MMP3, MMP13)), dedifferentiation (collagen 1) markers, inflammation markers (interleukin-6 (IL-6), nuclear factor kappa B (NFkB), cyclooxygenase-2 (COX), prostaglandin-E-synthase-2 (PTGES2)), and the apoptosis marker caspase 3 was determined. At the protein level, concentrations of IL-6, nitric oxide (NO), and sulfated glycosaminoglycans (GAG) were evaluated. Statistical analysis was performed using the independent t-test, and significance was defined as p < 0.05. In general, TNFα caused a decrease in anabolic markers and an increase in the expression of catabolic and inflammatory markers. There was a concentration-dependent threshold of 10 ng/mL to induce significant inflammatory effects. Most of the markers analyzed showed TNFα concentration-dependent effects (COMP, PRG4, AGN, Col1, MMP3, and NFkB). There was a statistical influence of selected gene expression markers from different passages on the TNFα chondrocyte inflammation model, including Col2, MMP13, IL-6, NFkB, COX2, and PTGES2. Considering the expression of collagen 2 and MMP3, passage 3 chondrocytes showed a higher sensitivity to TNFα stimulation compared to passages 1 and 2. On the other hand, MMP13, IL-6, NFkB, and caspase 3 gene expression were lower in P3 chondrocytes compared to the other passages. On the protein level, inflammatory effects showed a similar pattern, with cytokine effects starting at 10 ng/mL and differences between the passages. TNFα had a detrimental effect on cartilage, with a clear threshold observed at 10 ng/mL. Although TNFα effects showed concentration-dependent patterns, this was not consistent for all markers. The selected passage showed a clear influence, especially on inflammation markers. Further experiments were warranted to explore the effects of TNFα concentration and passage in long-term stimulation.

Mesenchymal Stem Cell-Derived Exosomes as a Treatment Option for Osteoarthritis

Osteoarthritis (OA) is a leading cause of pain and disability worldwide in elderly people. There is a critical need to develop novel therapeutic strategies that can effectively manage pain and disability to improve the quality of life for older people. Mesenchymal stem cells (MSCs) have emerged as a promising cell-based therapy for age-related disorders due to their multilineage differentiation and strong paracrine effects. Notably, MSC-derived exosomes (MSC-Exos) have gained significant attention because they can recapitulate MSCs into therapeutic benefits without causing any associated risks compared with direct cell transplantation. These exosomes help in the transport of bioactive molecules such as proteins, lipids, and nucleic acids, which can influence various cellular processes related to tissue repair, regeneration, and immune regulation. In this review, we have provided an overview of MSC-Exos as a considerable treatment option for osteoarthritis. This review will go over the underlying mechanisms by which MSC-Exos may alleviate the pathological hallmarks of OA, such as cartilage degradation, synovial inflammation, and subchondral bone changes. Furthermore, we have summarized the current preclinical evidence and highlighted promising results from in vitro and in vivo studies, as well as progress in clinical trials using MSC-Exos to treat OA.

4-Octyl itaconate protects chondrocytes against IL-1β-induced oxidative stress and ferroptosis by inhibiting GPX4 methylation in osteoarthritis

The role of oxidative stress and ferroptosis in osteoarthritis (OA) pathogenesis is increasingly recognized. Notably, 4-octyl Itaconate (OI) has been documented to counteract oxidative stress and inflammatory responses, highlighting its therapeutic potential in OA. This study explored the effects of OI on GPX4 methylation, oxidative stress, and ferroptosis in chondrocytes affected by OA. Our results demonstrated that OI mitigated IL-1β-induced chondrocyte degeneration in a dose-dependent manner. It also suppressed reactive oxygen species (ROS) production and sustained GPX4 expression, thereby attenuating the degenerative impact of IL-1β and Erastin on chondrocytes by curtailing ferroptosis. Moreover, we observed that blocking GPX4 methylation could alleviate IL-1β-induced degeneration, oxidative stress, and ferroptosis in chondrocytes. The regulatory mechanism of OI on GPX4 expression in chondrocytes involved the inhibition of GPX4 methylation. In a mouse model of OA, OI's protective effects against OA were comparable to those of Ferrostatin-1. Thus, OI reduced chondrocyte degeneration, oxidative stress, and ferroptosis by inhibiting GPX4 methylation, offering a novel mechanistic insight into its therapeutic application in OA.

Common outpatient diagnoses and associated treatments logged by osteopathic medical students within a geriatric population

CONTEXT

Clinical clerkships provide osteopathic medical students the opportunity to participate in the diagnosis and treatment of commonly encountered medical conditions. Appropriate management of these conditions may include pharmacotherapy and/or nonpharmacologic interventions, such as osteopathic manipulative treatment (OMT). Opportunities may exist to expand the utilization of OMT in the management of common conditions, particularly for geriatric patients, who are at increased risk for adverse outcomes from pharmacologic treatments.

OBJECTIVES

This study aimed to assess the most common diagnoses and corresponding treatments logged by osteopathic medical students within an ambulatory geriatric population.

METHODS

Patient encounters logged electronically by osteopathic medical students were retrospectively reviewed to determine the most commonly reported diagnostic codes and their treatments. Logged interventions were filtered to include patients over the age of 65 years who were seen on family medicine rotations within an ambulatory setting. The top 10 diagnoses were sorted and assessed to determine the associated treatments, including medications, procedures, and OMT.

RESULTS

Between January 2018 and June 2020, a total of 11,185 primary diagnoses were logged pertaining to the defined patient population. The most frequently documented diagnoses were essential hypertension (n=1,420; 12.7 %), encounter for well examination (n=1,144; 10.2 %), type 2 diabetes mellitus (n=837; 7.5 %), hyperlipidemia (n=346; 3.1 %), chronic obstructive pulmonary disease (COPD; n=278; 2.5 %), osteoarthritis (OA; n=221; 2.0 %), low back pain (LBP; n=202; 1.8 %), pain in joint (n=187; 1.7 %), hypothyroidism (n=164; 1.5 %), and urinary tract infections (n=160; 1.4 %). Three of the top 10 logged diagnoses were musculoskeletal in nature (OA, LBP, and pain in joint). Pharmacotherapy was reported as the predominant treatment for musculoskeletal conditions, with OMT being logged as a treatment for 10.9 % (n=50) of those cases. The most commonly logged medication class in the management of patients with those musculoskeletal conditions was nonsteroidal anti-inflammatory drugs (NSAIDs; n=128; 27.9 %), while opioids were the second most frequently documented class of medications (n=65; 14.2 %).

CONCLUSIONS

Musculoskeletal complaints were commonly logged by osteopathic medical students within the studied population. Opioids were documented as a treatment for musculoskeletal conditions more frequently than OMT. As such, opportunities exist to expand the utilization of OMT during clinical clerkships and to decrease the frequency of prescribed medications for pain management.

Cigarette smoke extract exacerbates progression of osteoarthritic-like changes in cartilage explant cultures

Established risk factors for osteoarthritis (OA) include obesity, joint injury, age, race, and genetics. However, the relationship between cigarette smoking and OA has yet to be established. In the present study, we have employed the use of cigarette smoke extract (CSE), the water-soluble vapor phase of cigarette smoke, with porcine cartilage explants to investigate the effects of cigarette smoking on cartilage catabolism at the tissue level. Articular cartilage explants were first exposed to 2.5%, 5%, and 10% CSE to assess its effects on cartilage homeostasis. Following, the effects of CSE on OA-like inflammation was observed by culturing explants with a combined treatment of IL-1β and TNF-α and 10% CSE (CSE + OA). Cartilage explants were assessed for changes in viability, biochemical composition, extracellular matrix (ECM) integrity, and equilibrium mechanical properties (aggregate modulus and hydraulic permeability). CSE alone leads to both a time- and dose-dependent decrease in chondrocyte viability but does not significantly affect sGAG content, percent sGAG loss, or the ECM integrity of cartilage explants. When IL-1β and TNF-α were combined with 10% CSE, this led to a synergistic effect with more significant losses in viability, significantly more sGAG loss, and significantly higher production of ROS than OA-like inflammation only. Cartilage explant equilibrium mechanical properties were unaffected. Within the timeframe of this study, CSE alone does not cause OA but when combined with OA-like inflammation leads to worsened articular cartilage degeneration as measured by chondrocyte viability, sGAG loss, proteoglycan staining, and ROS production.

Potential use of stem cell therapies for treating osteoarthritis and rheumatoid arthritis

Arthritis, defined as a chronic inflammation often accompanied by swelling of one or more joints, encompasses more than 100 conditions that affect the joints, tissues around them as well as other connective tissues. This condition causes severe discomfort compromising the quality of life drastically, and thereby inflicts severe financial and social impact on the people affected. The incidence rate of arthritis is increasing all around the globe including the United States every year. In general, osteoarthritis (OA) affects more people in comparison to rheumatoid arthritis (RA). In the USA itself, more than 14 million people are affected by OA in comparison to 1.4 million people suffering from RA. In both conditions, elevated levels of proinflammatory cytokines have been recorded, this incidence generally precedes the cartilage degradation observed in the patients. The use of mesenchymal stem cells (MSCs) has proven to be a safe and efficient therapeutic option for treating many inflammation-rooted pathological conditions. Evidence suggests that MSCs down-regulate the effects of proinflammatory cytokines including tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-1B, IL-2, and IL-17, and help restore the functions of immune cells. In addition, these cells promote the polarization of M2 phenotype macrophages, thus contributing to the suppression of the inflammatory process and consequentially to cartilage regeneration. Preclinical and clinical trials have proven the safety and effectiveness of this therapy, supported by the fact that these do not provoke any host immune response, and their influence on the cytokine profiles. An attempt to survey the results of stem cell therapy for treating arthritis has been carried out in this review.

Association of thyroid hormone with osteoarthritis: from mendelian randomization and RNA sequencing analysis

BACKGROUND

The relationship between thyroid hormone (TH) levels in vivo and osteoarthritis (OA) remains inconclusive. This study aims to investigate the association between TH levels and OA, analyze the effect of triiodothyronine on hypertrophic chondrocyte differentiation and OA progression, and identify potential target genes of triiodothyronine in OA to evaluate its diagnostic value.

METHODS

Two-sample mendelian randomization method was used to probe the causal links between hyperthyroidism and OA. Differentially expressed genes (DEGs) from two RNA-sequencing data in Gene Expression Omnibus (GSE199847 and GSE114007) and enrichment analysis of DEGs (166 commonly upregulated genes and 71 commonly downregulated genes of GSE199847 and GSE114007) was performed to analyze the effect of triiodothyronine (T3) on hypertrophic chondrocyte differentiation and OA. C28/I2 cells treated with T3 and reverse transcription and quantitative real-time polymerase chain reaction were used to validate T3 targeted genes. The diagnostic performance of target genes was assessed by the receiver operating characteristic (ROC) curve and area under the curve (AUC).

RESULTS

There was a positive causal association between hyperthyroidism and OA (IVW result, OR = 1.330, 95% CI 1.136-1.557, P = 0.0004). Weighted median and Weighted mode analysis also demonstrated that hyperthyroidism had a positive causal association with OA (p < 0.05, OR > 1). Bioinformatics analysis indicated T3 can partially induce the emergence of late hypertrophic chondrocyte and promote OA through extracellular matrix organization, blood vessel development, skeletal system development and ossification. Post-T3 treatment, MAFB, C1QTNF1, COL3A1 and ANGPTL2 were significantly elevated in C28/I2 cells. ROC curves in GSE114007 showed that AUC of all above genes were ≥ 0.7.

CONCLUSIONS

This study identified that hyperthyroidism has a positive causal association with OA by MR analysis. T3 induced hypertrophic chondrocytes promote OA progression by upregulating genes such as MAFB, C1QTNF1, COL3A1 and ANGPTL2, which can also serve as OA diagnosis.

Coenzyme-A-Responsive Nanogel-Coated Electrochemical Sensor for Osteoarthritis-Detection-Based Genetic Models

An electrochemical sensor sensitive to coenzyme A (CoA) was designed using a CoA-responsive polyallylamine-manganese oxide-polymer dot nanogel coated on the electrode surface to detect various genetic models of osteoarthritis (OA). The CoA-responsive nanogel sensor responded to the abundance of CoA in OA, causing the breakage of MnO2 in the nanogel, thereby changing the electroconductivity and fluorescence of the sensor. The CoA-responsive nanogel sensor was capable of detecting CoA depending on the treatment time and distinguishing the response towards different OA genetic models that contained different levels of CoA (wild type/WT, NudT7 knockout/N7KO, and Acot12 knockout/A12KO). The WT, N7KO, and A12KO had distinct resistances, which further increased as the incubation time were changed from 12 h (R12h = 2.11, 2.40, and 2.68 MΩ, respectively) to 24 h (R24h = 2.27, 2.59, and 2.92 MΩ, respectively) compared to the sensor without treatment (Rcontrol = 1.63 MΩ). To simplify its application, the nanogel sensor was combined with a wireless monitoring device to allow the sensing data to be directly transmitted to a smartphone. Furthermore, OA-indicated anabolic (Acan) and catabolic (Adamts5) factor transcription levels in chondrocytes provided evidence regarding CoA and nanogel interactions. Thus, this sensor offers potential usage in simple and sensitive OA diagnostics.