Epidemiology of osteoarthritis: literature update

DSCR1-1 attenuates osteoarthritis-associated chondrocyte injury by regulating the CREB1/ALDH2/Wnt/β-catenin axis: An in vitro and in vivo study

The progression of osteoarthritis (OA) includes the initial inflammation, subsequent degradation of the extracellular matrix (ECM), and chondrocyte apoptosis. Down syndrome candidate region 1 (DSCR1) is a stress-responsive gene and expresses in varied types of cells, including chondrocytes. Bioinformatics analysis of GSE103416 and GSE104739 datasets showed higher DSCR1 expression in the inflamed cartilage tissues and chondrocytes of OA. DSCR1 had two major isoforms, isoform 1 (DSCR1-1) and isoform 4 (DSCR1-4). We found that DSCR1-1 had a faster (in vitro) and higher expression (in vivo) response to OA compared to DSCR1-4. IL-1β-induced apoptosis, inflammation, and ECM degradation in chondrocytes were attenuated by DSCR1-1 overexpression. DSCR1-1 triggered the phosphorylation of cAMP response element-binding 1 (CREB1) at 133 serine sites by decreasing calcineurin activity. Moreover, activated CREB1 moved into the cell nucleus and combined in the promoter regions of aldehyde dehydrogenase 2 (ALDH2), thus enhancing its gene transcription. ALDH2 could recover Wnt/β-catenin signaling transduction by enhancing phosphorylation of β-catenin at 33/37 serine sites and inhibiting the migration of β-catenin protein from the cellular matrix to the nucleus. In vivo, adenoviruses (1 × 108 PFU) overexpressing DSCR1-1 were injected into the articular cavity of C57BL/6 mice with medial meniscus surgery-induced OA, and it showed that DSCR1-1 overexpression ameliorated cartilage injury. Collectively, our study demonstrates that DSCR1-1 may be a potential therapeutic target of OA.

Transcriptomics and metabolomics: Challenges of studying obesity in osteoarthritis

Objective

Obesity is a leading risk factor for both the incidence and progression of osteoarthritis (OA). Omic technologies, including transcriptomics and metabolomics are capable of identifying RNA and metabolite profiles in tissues and biofluids of OA patients. The objective of this review is to highlight studies using transcriptomics and metabolomics that contribute to our understanding of OA pathology in relation to obesity.

Design

We conducted a targeted search of PUBMED for articles, and GEO for datasets, published up to February 13, 2024, screening for those using high-throughput transcriptomic and metabolomic techniques to study human or pre-clinical animal model tissues or biofluids related to obesity-associated OA. We describe relevant studies and discuss challenges studying obesity as a disease-related factor in OA.

Results

Of the 107 publications identified by our search criteria, only 15 specifically used transcriptomics or metabolomics to study joint tissues or biofluids in obesity-related OA. Specific transcriptomic and metabolomic signatures associated with obesity-related OA have been defined in select local joint tissues, biofluids and other biological material. However, considerable challenges exist in understanding contributions of obesity-associated modifications of transcriptomes and metabolomes related to OA, including sociodemographic, anthropometric, dietary and molecular redundancy-related factors.

Conclusions

A number of additional transcriptomic and metabolomic studies are needed to comprehensively understand how obesity affects OA incidence, progression and outcomes. Integration of transcriptome and metabolome signatures from multiple tissues and biofluids, using network-based approaches will likely help to better define putative therapeutic targets that could enable precision medicine approaches to obese OA patients.

Non-pharmacological and non-surgical interventions to manage patients with knee osteoarthritis: An umbrella review 5-year update

Objective

This umbrella review aimed to summarize (and update) the effectiveness of non-pharmacological and non-surgical interventions for patients with knee osteoarthritis.

Methods

The study followed the PRISMA guidelines. Manual and electronic databases were searched, to identify systematic reviews, following the P (knee osteoarthritis) I (non-pharmacological and non-surgical treatments) C (pharmacological, surgical, placebo, no intervention, or other non-pharmacological/non-surgical conservative treatments) O (pain, function, quality of life, and other knee-specific measures) model. The quality of evidence was assessed using the R-AMSTAR checklist and GRADE principles.

Results

The search yielded 4086 records, of which 61 met the eligibility criteria. After evaluation with R-AMSTAR, four systematic reviews were excluded, resulting in 57 included systematic reviews, with an overall score of 29.6. The systematic reviews were published between 2018 and 2022 (29.8% in 2022), conducted in 19 countries (52.6% in China), and explored 24 distinct interventions. The systematic reviews encompassed 714 trials (mean of 13 ​± ​7.7 studies per systematic review), and 59,343 participants (mean 1041 ​± ​1002 per systematic review, and 82 ​± ​59.2 per study). The majority of participants were older obese women (61.6 ​± ​4.2 years, 30.2 ​± ​3.6 ​kg/m2, 70%, respectively).

Conclusions

Based on the systematic reviews findings, Diet Therapy, Patient Education, and Resistance Training are strongly supported as core interventions for managing patients with knee osteoarthritis. Aquatic Therapy, Balance Training, Balneology, Dietary Supplements, Extracorporeal Shockwave Therapy, and Tai Ji show moderate support. For other interventions, the evidence quality was low, results were mixed or inconclusive, or there was not sufficient efficacy to support their use.

Increased Wnt5a/ROR2 signaling is associated with chondrogenesis in meniscal degeneration

The aim of the present study was to investigate the association between chondrogenic differentiation and Wnt signal expression in the degenerative process of the human meniscus. Menisci were obtained from patients with and without knee osteoarthritis (OA), and degeneration was histologically assessed using a grading system. Immunohistochemistry, real-time polymerase chain reaction (PCR), and Western blot analysis were performed to examine the expressions of chondrogenic markers and of the components of Wnt signaling. Histological analyses showed that meniscal degeneration involved a transition from a fibroblastic to a chondrogenic phenotype with the upregulation of SOX9, collagen type II, collagen type XI, and aggrecan, which were associated with increased Wnt5a and ROR2 and decreased TCF7 expressions. OA menisci showed significantly higher expressions of Wnt5a and ROR2 and significantly lower expressions of AXIN2 and TCF7 than non-OA menisci on real-time PCR and Western blot analysis. These results potentially demonstrated that increased expression of Wnt5a/ROR2 signaling promoted chondrogenesis with decreased expression in downstream Wnt/β-catenin signaling. This study provides insights into the role of Wnt signaling in the process of meniscal degeneration, shifting to a chondrogenic phenotype. The findings suggested that the increased expression of Wnt5a/ROR2 and decreased expression of the downstream target of Wnt/β-catenin signaling are associated with chondrogenesis in meniscal degeneration.

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

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

Bushen Huoxue decotion-containing serum prevents chondrocyte pyroptosis in a m6A-dependent manner in facet joint osteoarthritis

BACKGROUND

Facet joint osteoarthritis (FJOA) is a common lumbar osteoarthritis characterized by degeneration of small joint cartilage. Bushen Huoxue decotion (BSHXD) has good therapeutic effects on OA. Our work aimed to further probe the pharmacological effects of BSHXD-containing serum (BSHXD-CS) on FJOA and define underlying the mechanisms invovled.

METHODS

To establish a FJOA cell model, primary rat chondrocytes were treated with LPS. The mRNA and protein expressions were assessed using qRT-PCR and western blot, respectively. The secretion levels of pro-inflammatory cytokines were measured by ELISA. Cell viability was determined by CCK8 assay. The global m6A level was detected by the kit, and NLRP3 mRNA m6A level was determined by Me-RIP assay. The molecular interactions were analyzed by RIP and RNA pull-down assays.

RESULTS

BSHXD-CS treatment relieved LPS-induced cell injury, inflammation, NLRP3 inflammasome and pyroptosis in chondrocytes (all p < 0.05). LPS-induced NLRP3 upregulation in chondrocytes was related to its high m6A modification level (p < 0.05). It was also observed that BSHXD-CS reduced LPS-induced m6A modification in chondrocytes via repressing STAT3 (all p < 0.05), suggesting BSHXD-CS could repress NLRP3 expression via m6A-dependent manner. Moreover, DAA, a m6A specific inhibitor, was proved to strengthen the protectively roles of BSHXD-CS on LPS-challenged pytoptosis (all p < 0.05).

CONCLUSION

BSHXD-CS inhibited NLRP3 inflammasome activation and pyroptosis in chondrocytes to repress OA progression by reducing RNA m6A modification.

Evaluation of the effect of low-intensity pulsed ultrasound in pain and dysfunction for knee osteoarthritis: a double-blind, randomised controlled trial protocol

INTRODUCTION

Osteoarthritis (OA) is the most common joint disorder among musculoskeletal conditions. Non-surgical treatment is the standard therapy for knee OA (KOA). Ultrasound therapy is recommended for alleviating pain and dysfunction from OA, but high-quality scientific evidence for its effectiveness in OA treatment is still lacking.Therefore, we want to analyse whether combining conventional physical therapy with low-intensity pulsed ultrasound (LIPUS) can enhance the efficacy of conventional therapy, thus improving symptoms in patients with KOA.

METHODS AND ANALYSIS

This randomised controlled trial aims to recruit 200 patients diagnosed with KOA, aged 38 years or above, who meet the clinical diagnostic criteria for KOA. Patients will be randomly assigned in a 1:1 ratio to either a LIPUS treatment group or a sham ultrasound treatment control group. The 2-week treatment will consist of five sessions per week and evaluations will take place at baseline, on the day of the last intervention and 1 month post intervention. The main outcome measures will be the Western Ontario and McMaster Universities' scores. Secondary outcome indicators will be the Numerical Pain Rating Scale, the Lequesne scale, the time up and go test and the range of motion of the knee. An intention-to-treat analysis will be performed for dropouts and missing data.

ETHICS AND DISSEMINATION

The study was approved by the ethics committee of Shengjing Hospital of China Medical University (2023PS592K). Findings will be disseminated to participants and made available to peer-reviewed journals.

TRIAL REGISTRATION NUMBER

The trial was registered on the Chinese Clinical Trial Registry platform (chictr.org.cn) on 22 March 2023, with the registration ID ChiCTR2300069643.

Evolution and advancements in genomics and epigenomics in OA research: How far we have come

OBJECTIVE

Osteoarthritis (OA) is the most prevalent musculoskeletal disease affecting articulating joint tissues, resulting in local and systemic changes that contribute to increased pain and reduced function. Diverse technological advancements have culminated in the advent of high throughput "omic" technologies, enabling identification of comprehensive changes in molecular mediators associated with the disease. Amongst these technologies, genomics and epigenomics - including methylomics and miRNomics, have emerged as important tools to aid our biological understanding of disease.

DESIGN

In this narrative review, we selected articles discussing advancements and applications of these technologies to OA biology and pathology. We discuss how genomics, deoxyribonucleic acid (DNA) methylomics, and miRNomics have uncovered disease-related molecular markers in the local and systemic tissues or fluids of OA patients.

RESULTS

Genomics investigations into the genetic links of OA, including using genome-wide association studies, have evolved to identify 100+ genetic susceptibility markers of OA. Epigenomic investigations of gene methylation status have identified the importance of methylation to OA-related catabolic gene expression. Furthermore, miRNomic studies have identified key microRNA signatures in various tissues and fluids related to OA disease.

CONCLUSIONS

Sharing of standardized, well-annotated omic datasets in curated repositories will be key to enhancing statistical power to detect smaller and targetable changes in the biological signatures underlying OA pathogenesis. Additionally, continued technological developments and analysis methods, including using computational molecular and regulatory networks, are likely to facilitate improved detection of disease-relevant targets, in-turn, supporting precision medicine approaches and new treatment strategies for OA.

Flavan-3-ol monomers intake is associated with osteoarthritis risk in Americans over 40 years of age: results from the National Health and Nutritional Examination Survey database

Objectives: Osteoarthritis (OA) stands as the prevailing progressive musculoskeletal disease, serving as the primary cause of chronic pain and activity limitations among adults over 40. Flavan-3-ols, common polyphenolic compounds, are believed to harbor anti-inflammatory and anti-aging properties. This study explores the relationship between flavan-3-ol intake and osteoarthritis risk in individuals over the age of 40 in the US. Methods: This study included 7452 participants over the age of 40 from three cycles (2007-2008, 2009-2010, and 2017-2018) of the National Health and Nutrition Examination Survey. Information on OA history was obtained via home surveys. Information on flavan-3-ol monomers intake was obtained using a survey from the Food and Nutrient Database for Dietary Studies. We used a logistic regression model and restricted cubic spline to analyze the relationships between flavan-3-ol monomers and OA. Stratified analyses were also conducted in this study. Results: There were 1056 participants with OA and 6396 without OA. Compared to the first tertile (T1) group, the adjusted odds ratio with a 95% confidence interval (CI) of logistic regression model 2 for the flavan-3-ol T2 group was 1.296 (0.979-1.715) (p = 0.068), the OR for (-)-epigallocatechin was 1.292 (1.025-1.629) (p = 0.032), and the OR for (-)-epicatechin 3-gallate was 1.348 (1.013, 1.793) (p = 0.042). A dose-response curve indicated a non-linear association (p for non-linearity <0.05) between OA and total flavan-3-ol monomers (nadir point: 483.29 mg, 95% CI: 0.61-0.90). No interaction effects were found in the subgroup analysis. Conclusions: In individuals over 40 in the US, the average daily dietary intake of flavan-3-ol monomers manifests a J-shaped relationship with OA risk.

The impact of thyroid function on total spine bone mineral density in postmenopausal women

PURPOSE

Osteoporosis has been a widespread concern for older women, especially postmenopausal women. Thyroid function is crucial for bone metabolism. However, the relationship between thyroid function variation within thyroxine reference range and bone mineral density (BMD) remains ambiguous. The objective of this study was to evaluate the effect of subclinical hypothyroidism or hyperthyroidism on total spinal BMD in postmenopausal women.

METHODS

Based on data from the National Health and Nutrition Examination Survey (NHANES) 2007-2010, multivariable weighted logistic regression was used to evaluate the relationships between total spine BMD and TSH among postmenopausal women aged ≥50.

RESULTS

After accounting for a number of variables, this study discovered that the middle TSH tertile was associated with a decreased probability of osteoporosis. Additionally, the subgroup analysis revealed that postmenopausal women over the age of 65 or people with an overweight BMI had a clearer relationship between total spine BMD and TSH.

CONCLUSION

The total spinal BMD had a positive relationship with thyroid stimulating hormone in postmenopausal women, and that appropriate TSH level (1.38-2.32 mIU/L) was accompanied by higher total spinal BMD.

Novel nano-in-micro fabrication technique of diclofenac nanoparticles loaded microneedle patches for localised and systemic drug delivery

Diclofenac, a nonsteroidal anti-inflammatory drug, is commonly prescribed for managing osteoarthritis, rheumatoid arthritis, and post-surgical pain. However, oral administration of diclofenac often leads to adverse effects. This study introduces an innovative nano-in-micro approach to create diclofenac nanoparticle-loaded microneedle patches aimed at localised, sustained pain relief, circumventing the drawbacks of oral delivery. The nanoparticles were produced via wet-milling, achieving an average size of 200 nm, and then incorporated into microneedle patches. These patches showed improved skin penetration in ex vivo tests using Franz-cell setups compared to traditional diclofenac formulations. In vivo tests on rats revealed that the nanoparticle-loaded microneedle patches allowed for quick drug uptake and prolonged release, maintaining drug levels in tissues for up to 72 h. With a systemic bioavailability of 57 %, these patches prove to be an effective means of transdermal drug delivery. This study highlights the potential of this novel microneedle delivery system in enhancing the treatment of chronic pain with reduced systemic side effects.

A phase 2b double-blind placebo-controlled randomized clinical trial of SB-061, an aggrecan mimetic, in patients with symptomatic knee osteoarthritis

OBJECTIVES

To evaluate the efficacy and safety of intra-articular injections of a novel aggrecan mimetic, SB-061, in subjects with knee osteoarthritis (OA).

METHODS

This was a randomized, placebo-controlled, double-blind phase II study comparing intra-articular injections of SB-061 with placebo (isotonic saline) for 52 weeks, administered at baseline, Wk 16, and Wk 32. Eligible subjects had a KL grade of 2 or 3 on X-ray of the target knee and a Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) pain score ≥20 out of 50 at screening and baseline visits. Subjects having any other knee condition were excluded. Use of analgesics was prohibited, except for rescue medication. The primary endpoint was change from baseline (CFB) in WOMAC pain at Week 8. Secondary endpoints were CFB in WOMAC function and total, ICOAP, Patient Global Assessment, and 20-meter walk test. Exploratory endpoints included structural CFB in magnetic resonance imaging entities.

RESULTS

A total of 288 subjects were randomized to SB-061 (n = 145) or placebo (n = 143), and 252 (87.5%) completed injections. The groups were comparable at baseline. The primary endpoint was not met, as no significant difference in the CFB of the WOMAC pain score at Week 8 between groups was observed, nor at any other time point during the study. Similarly, neither of the secondary or exploratory endpoints indicated any significant difference between groups. The frequency and type of adverse events were similar between groups. SB-061 was well-tolerated.

CONCLUSION

Intra-articular injections of SB-061 administered at baseline, Week 16, and Week 32, over one year in subjects with knee OA, were safe but did not show any statistically significant effect on knee pain nor on other symptomatic or structural entities compared to placebo.

TRIAL REGISTRATION NUMBER EUDRACT NO

2019-004515-31.

Pharmacologic interventions for primary glenohumeral osteoarthritis

ABSTRACT

Primary glenohumeral osteoarthritis is a multifactorial condition with a complex cause that affects patients across different age groups, impairing physiologic and psychologic well-being, and substantially reducing patient quality of life and overall productivity. To effectively manage this condition, healthcare providers need to be well informed about treatment guidelines, as well as the available therapeutic options and the evidence supporting their use. Nonsurgical interventions should be regarded as the primary treatment option, particularly for patients in the initial phases of this condition. No conclusive guidelines exist for treating young and active patients, and the literature lacks high-quality data to evaluate the efficacy, safety, and long-term consequences of several interventions, regardless of patient characteristics and expectations.

Genicular Artery Embolization: A New Tool for the Management of Refractory Osteoarthritis-Related Knee Pain

Osteoarthritis (OA) of the knee is a prevalent cause of chronic pain and disability, particularly affecting women. While traditionally attributed to chronic wear and tear, recent evidence highlights multifactorial pathogenesis involving low-grade inflammation and neoangiogenesis. Current therapeutic options include physical therapy, pharmacotherapy, and total knee arthroplasty (TKA). However, a subset of patients remain symptomatic despite conservative measures, necessitating the development of minimally invasive interventions. Genicular artery embolization (GAE) emerges as a promising option, targeting neovascularization and inflammatory processes in OA. This paper reviews the pathophysiological basis, patient selection criteria, procedural details, and outcomes of GAE. Notably, GAE demonstrates efficacy in relieving knee pain and improving function in patients refractory to conventional therapy. While further research is warranted to elucidate its long-term outcomes and compare it with existing modalities, GAE represents a novel approach in the management of symptomatic knee OA, potentially delaying or obviating the need for surgical intervention. Here, we synthesize the relevant literature, technical details of the procedure, and future perspectives. Moreover, the success of GAE prompts the exploration of transarterial embolization in other musculoskeletal conditions, underscoring the evolving role of interventional radiology in personalized pain management strategies.

Diet influences knee osteoarthritis osteophyte formation via gut microbiota and serum metabolites

Osteophyte formation, a key indicator of osteoarthritis (OA) severity, remains poorly understood in its relation to gut microbiota and metabolites in knee osteoarthritis (KOA). We conducted 16S rDNA sequencing and untargeted metabolomics on fecal and serum samples from 20 healthy volunteers, 80 KOA patients in Guangdong, and 100 in Inner Mongolia, respectively. Through bioinformatics analysis, we identified 3 genera and 5 serum metabolites associated with KOA osteophyte formation. Blautia abundance negatively correlated with meat, cheese, and bean consumption. The 5 serum metabolites negatively correlated with dairy, beef, cheese, sugar, and salt intake, yet positively with age and oil consumption. Higher Blautia levels in the gut may contribute to KOA osteophyte formation, with serum metabolites LTB4 and PGD2 potentially serving as biomarkers. KOA patients in Inner Mongolia exhibited lower Blautia levels and reduced expression of 5 serum metabolites, possibly due to cheese consumption habits, resulting in less osteophyte formation.

Alterations in DNA methylation machinery in a rat model of osteoarthritis of the hip

BACKGROUND

This study aimed to validate alterations in the gene expression of DNA methylation-related enzymes and global methylation in the peripheral blood mononuclear cell (PBMC) and synovial tissues of animal hip osteoarthritis (OA) models.

METHODS

Animals were assigned to the control (no treatment), sham (25 µL of sterile saline), and OA (25 µL of sterile saline and 2 mg of monoiodoacetate) groups. Microcomputed tomography scan, histopathological assessment and pain threshold measurement were performed after induction. The mRNA expression of the DNA methylation machinery genes and global DNA methylation in the PBMC and hip synovial tissue were evaluated.

RESULTS

The OA group presented with hip joint OA histopathologically and radiologically and decreased pain threshold. The mRNA expression of DNA methyltransferase (Dnmt 3a), ten-eleven translocation (Tet) 1 and Tet 3 in the synovial tissue of the OA group was significantly upregulated. Global DNA methylation in the synovial tissue of the OA group was significantly higher than that of the control and sham groups.

CONCLUSIONS

The intra-articular administration of monoiodoacetate induced hip joint OA and decreased pain threshold. The DNA methylation machinery in the synovial tissues of hip OA was altered.

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

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

PLOD2 gene expression in infrapatellar fat pad is correlated with fat mass in obese patients with end-stage knee osteoarthritis

Objective

To investigate associations between obesity-linked systemic factors and gene expression indicative for the inflammatory and fibrotic processes in the infrapatellar fat pad (IFP), in a population of obese patients with end-stage knee osteoarthritis (KOA).

Methods

We collected human IFPs from 48 patients with a mean body mass index (BMI) of 35.44 ​kg/m2 during total knee replacement procedures. These patients were part of a randomized controlled trial and met the criteria of having OA and a BMI of ≥30 ​kg/m2. Blood samples were collected to assess serum levels of glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, and leptin. Total body composition was measured using dual-energy X-ray absorptiometry. Gene expressions of IL6, TNFA, COL1A1, IL1B, ASMA, PLOD2 in the IFP were analyzed.

Results

Univariate analysis resulted in a positive correlation between BMI and procollagen-lysine,2-oxoglutarate 5-dioxygenase 2 (PLOD2) expression (r2 ​= ​0.13). In univariate analyses of obesity-linked systemic factors and PLOD2, significant correlations were found for lean mass (r2 ​= ​0.20), fat mass (r2 ​= ​0.20), serum cholesterol (r2 ​= ​0.17), serum triglycerides (r2 ​= ​0.19) and serum leptin (r2 ​= ​0.10). A multiple linear regression model indicated fat mass to be a strong predictor of PLOD2 production in the IFP (r2 ​= ​0.22, P ​= ​0.003).

Conclusion

Our study demonstrates the positive association between fat mass and PLOD2 expression in the IFP of obese end-stage knee OA patients. This may indicate that within this patient population the fibrotic process in the IFP is influenced by systemic adipose tissue, next to local inflammatory processes.

Association between serum α-Klotho levels and osteoarthritis prevalence among middle-aged and older adults: an analysis of the NHANES 2007-2016

BACKGROUND

As individuals age, the prevalence of osteoarthritis tends to increase gradually. α-Klotho is a hormone renowned for its anti-aging properties. However, the precise role of serum α-Klotho in osteoarthritis is still not fully comprehended.

METHODS

We conducted a cross-sectional study utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2016. Serum α-Klotho levels were measured using an enzyme-linked immunosorbent assay (ELISA). Osteoarthritis was assessed through self-reported questionnaires. Through univariate and multivariate logistic regression analyses, smooth curve fitting, threshold effect analysis, and subgroup analyses, we delved into the potential association between them.

RESULTS

The study encompassed a cohort of 10,265 participants. In fully adjusted models of multivariate logistic regression analysis, we identified a negative correlation between serum ln α-Klotho and OA (OR = 0.77, 95% CI: 0.65-0.91, p = 0.003). When stratifying serum α-Klotho levels into tertiles, individuals in the highest tertile exhibited a 26% reduced risk of OA compared to those in the lowest tertile (OR = 0.84, 95% CI: 0.73-0.97, p = 0.014). Subsequent analyses indicated a linearly negative association. In subgroup analyses, we explored the relationship between serum ln α-Klotho and osteoarthritis across diverse populations, revealing the persistence of this association in the majority of subgroups.

CONCLUSION

Serum α-Klotho levels exhibit a significant negative linear correlation with the prevalence of osteoarthritis in middle-aged and elderly populations in the United States.

Increasing Collagen to Bioink Drives Mesenchymal Stromal Cells-Chondrogenesis from Hyaline to Calcified Layers

The bioextrusion of mesenchymal stromal cells (MSCs) directly seeded in a bioink enables the production of three-dimensional (3D) constructs, promoting their chondrogenic differentiation. Our study aimed to evaluate the effect of different type I collagen concentrations in the bioink on MSCs' chondrogenic differentiation. We printed 3D constructs using an alginate, gelatin, and fibrinogen-based bioink cellularized with MSCs, with four different quantities of type I collagen addition (0.0, 0.5, 1.0, and 5.0 mg per bioink syringe). We assessed the influence of the bioprinting process, the bioink composition, and the growth factor (TGF-ꞵ1) on the MSCs' survival rate. We confirmed the biocompatibility of the process and the bioinks' cytocompatibility. We evaluated the chondrogenic effects of TGF-ꞵ1 and collagen addition on the MSCs' chondrogenic properties through macroscopic observation, shrinking ratio, reverse transcription polymerase chain reaction, glycosaminoglycan synthesis, histology, and type II collagen immunohistochemistry. The bioink containing 0.5 mg of collagen produces the richest hyaline-like extracellular matrix, presenting itself as a promising tool to recreate the superficial layer of hyaline cartilage. The bioink containing 5.0 mg of collagen enhances the synthesis of a calcified matrix, making it a good candidate for mimicking the calcified cartilaginous layer. Type I collagen thus allows the dose-dependent design of specific hyaline cartilage layers.

Changes in educational inequalities in knee and hip osteoarthritis surgery and non-surgery specialist care visits over time in Sweden

Objective

To examine changes in prevalence and socioeconomic inequalities in knee and hip OA outcomes, in more specific surgery and non-surgery specialist care visits, from 2001 to 2011 in Sweden and to what extent sociodemographic factors can explain the changes.

Design

We included all individuals aged ≥35 years resident in Sweden from 2001 to 2011. Individual-level data was retrieved from the Swedish Interdisciplinary Panel. Highest educational attainment was used as socioeconomic measure and the concentration index was used to assess relative and absolute educational inequalities. We used decomposition method to examine changes in prevalence and relative educational inequalities.

Results

A total of 4,794,693 and 5,359,186 people were included for the years 2001 and 2011, respectively. The crude prevalence of surgery and specialist visits for knee and hip OA was 36-83% higher in 2011 than in 2001. The increase in hip OA outcomes was largely explained by changes in the sociodemographic composition of the population, whereas for knee OA outcomes, changes in the strength of the associations with sociodemographic factors appeared more important. All outcomes were concentrated among people with lower education in all study years. The relative inequalities declined over the study period, while the absolute inequalities increased for knee OA outcomes and remained stable for hip OA.

Conclusion

Our findings show an increasing burden of all studied OA outcomes. Moreover, our findings suggest persistent educational inequalities with more surgeries and specialist visits among lower-educated individuals. Future research should incorporate additional variables to better understand and address these inequalities.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Therapeutic mechanisms of modified Jiawei Juanbi decoction in early knee osteoarthritis: A multimodal analysis

Modified Jiawei Juanbi decoction (MJD) is used for the treatment of early-stage knee osteoarthritis (KOA). Here, modified Jiawei Juanbi decoction (MJD) was employed for the treatment of early-stage knee osteoarthritis (KOA) and its mechanisms were assessed via metabonomics and network pharmacology. A total of 24 male Sprague-Dawley rats were randomly allocated into a normal control group, a model group, and an MJD group (n = 8 rats per group). Each rat group was further equally divided into two subgroups for investigation for either 14 or 28 days. A rat model of early-stage KOA was constructed and rats were treated with MJD. Effects were evaluated based on changes in knee circumference, mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL). We also analyzed histopathological changes in articular cartilage. High-resolution mass spectrometry was used to analyze the chemical profile of MJD, identifying 228 components. Using an LC-Q-TOF-MS metabonomics approach, 33 differential metabolites were identified. The relevant pathways significantly associated with MJD include arginine and proline metabolism, vitamin B6 metabolism, as well as the biosynthesis of phenylalanine, tyrosine and tryptophan. The system pharmacology paradigm revealed that MJD contains 1027 components and associates with 1637 genes, of which 862 disease genes are related to osteoarthritis. The construction of the MJD composition-target-KOA network revealed a total of 140 intersection genes. A total of 39 hub genes were identified via integration of betweenness centrality values greater than 100 using CytoHubba. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed several significantly affected signaling pathways including the HIF-1, AGE-RAGE (in diabetic complications), IL-17, rheumatoid arthritis and TNF pathways. Integrated-omics and network pharmacology approaches revealed a necessity for further detailed investigation focusing on two major targets, namely NOS2 and NOS3, along with their essential metabolite (arginine) and associated pathways (HIF-1 signaling and arginine and proline metabolism). Real-time PCR validated significantly greater downregulation of NOS2 and HIF-1ɑ in the MJD as compared to the model group. Molecular docking analysis further confirmed the binding of active MJD with key active components. Our findings elucidate the impact of MJD on relevant pathophysiological and metabolic networks relevant to KOA and assess the drug efficacy of MJD and its underlying mechanisms of action.

Intra-articular steroids for the treatment of coxarthrosis; a retrospective cohort study comparing three contrast techniques

INTRODUCTION

Intra-articular steroid injections (IAS) are a treatment for coxarthrosis. This study examines the efficacy of three fluoroscopy-guided IAS contrast techniques for coxarthrosis: contrast-assisted (Iohexol), air arthrogram-assisted and blind (contrast/air free) and stratifies efficacy based on multiple patient variables.

MATERIALS AND METHODS

A cohort of 307 hip IAS was retrospectively analysed over a four-year period. The primary outcome was efficacy of IAS between each technique group, defined by duration of symptomatic relief. The secondary outcome was efficacy based on multiple patient variables. Variables included age, BMI, gender, type of osteoarthritis, grade of osteoarthritis, smoking status, co-morbidity index and duration of pre-injection symptoms. Chi-squared, Pearson, One Way ANOVA and F-tests were used for statistical analysis.

RESULTS

Total failure (< 1 week symptomatic relief) was 20% (contrast 20%, air 14%, blind 26%). >3 months of symptomatic relief was experienced by 35%, with the air arthrogram technique containing the largest proportion of IAS achieving > 3months of relief within its own group (contrast 35%, air 38%, blind 28%). Non-smokers experienced a longer duration of symptomatic relief in the air arthrogram group (p = 0.04). Older patients had a longer duration of symptomatic relief with the blind technique (p = < 0.001). There were no significant differences between the three techniques based on the other patient variables.

CONCLUSION

Air arthrogram is an effective method of confirming injection placement in hip IAS for coxarthrosis and the use of a contrast agent (e.g., Iohexol) may not be required. Non-contrast techniques may produce longer duration of symptomatic relief in non-smokers and in older patients.

Omega-3 Supplementation and Its Effects on Osteoarthritis

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

Association between physical measures of spinopelvic alignment and physical functioning with patient reported outcome measures (PROMs) after total hip arthroplasty: Protocol for systematic review and meta-analysis

INTRODUCTION

Prevalence of total hip arthroplasty (THA) has trended upwards over past decades and is projected to increase further. Optimizing outcomes after surgery is essential to avoid surgical revision and maximize outcomes. Low back pain is reported as a problem post THA. Patient-reported outcome measures (PROMs) are commonly used to evaluate THA outcomes but have limitations (e.g., ceiling effects). It is therefore important to assess a comprehensive range of outcomes. Physical outcome measures of spinopelvic alignment and physical functioning demonstrate potential value, but no evidence synthesis has investigated their association with PROMs. The objectives of this systematic review are to evaluate the association between spinopelvic alignment and physical outcome measures of physical functioning with PROMs and characteristics of low back pain after THA.

METHODS AND ANALYSIS

This protocol is aligned with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. Cross-sectional and longitudinal cohort studies evaluating the association between the physical outcome measures and PROMs (any outcome measures reported) following THA by any approach/implant will be included except surface replacement and revision THA. Studies investigating THA for developmental pathology and inflammatory conditions will be excluded. A systematic search in MEDLINE (Ovid), Embase (Ovid), Scopus, Web of Science, CINAHL, and the grey literature will be carried out from inception to July 31, 2023. Two independent reviewers will evaluate eligibility of retrieved articles, extract data and assess risk of bias (NIH quality assessment tool) of included studies. A third reviewer will mediate disagreements. Random-effects meta-analyses will be conducted if studies are sufficiently homogeneous in design, population, physical measures and PROMs; reporting odds ratios and 95% confidence intervals. Where meta-analyses are not possible, a narrative synthesis will be conducted. Confidence in cumulative evidence will be assessed using a modified GRADE (Grading of Recommendations Assessment, Development, and Evaluation).

PROSPERO REGISTRATION NUMBER

PROSPERO Registration number CRD42023412744.

Analysis of common differential gene expression in synovial cells of osteoarthritis and rheumatoid arthritis

OBJECTIVE

To elucidate potential molecular mechanisms differentiating osteoarthritis (OA) and rheumatoid arthritis (RA) through a bioinformatics analysis of differentially expressed genes (DEGs) in patient synovial cells, aiming to provide new insights for clinical treatment strategies.

MATERIALS AND METHODS

Gene expression datasets GSE1919, GSE82107, and GSE77298 were downloaded from the Gene Expression Omnibus (GEO) database to serve as the training groups, with GSE55235 being used as the validation dataset. The OA and RA data from the GSE1919 dataset were merged with the standardized data from GSE82107 and GSE77298, followed by batch effect removal to obtain the merged datasets of differential expressed genes (DEGs) for OA and RA. Intersection analysis was conducted on the DEGs between the two conditions to identify commonly upregulated and downregulated DEGs. Enrichment analysis was then performed on these common co-expressed DEGs, and a protein-protein interaction (PPI) network was constructed to identify hub genes. These hub genes were further analyzed using the GENEMANIA online platform and subjected to enrichment analysis. Subsequent validation analysis was conducted using the GSE55235 dataset.

RESULTS

The analysis of differentially expressed genes in the synovial cells from patients with Osteoarthritis (OA) and Rheumatoid Arthritis (RA), compared to a control group (individuals without OA or RA), revealed significant changes in gene expression patterns. Specifically, the genes APOD, FASN, and SCD were observed to have lower expression levels in the synovial cells of both OA and RA patients, indicating downregulation within the pathological context of these diseases. In contrast, the SDC1 gene was found to be upregulated, displaying higher expression levels in the synovial cells of OA and RA patients compared to normal controls.Additionally, a noteworthy observation was the downregulation of the transcription factor PPARG in the synovial cells of patients with OA and RA. The decrease in expression levels of PPARG further validates the alteration in lipid metabolism and inflammatory processes associated with the pathogenesis of OA and RA. These findings underscore the significance of these genes and the transcription factor not only as biomarkers for differential diagnosis between OA and RA but also as potential targets for therapeutic interventions aimed at modulating their expression to counteract disease progression.

CONCLUSION

The outcomes of this investigation reveal the existence of potentially shared molecular mechanisms within Osteoarthritis (OA) and Rheumatoid Arthritis (RA). The identification of APOD, FASN, SDC1, TNFSF11 as key target genes, along with their downstream transcription factor PPARG, highlights common potential factors implicated in both diseases. A deeper examination and exploration of these findings could pave the way for new candidate targets and directions in therapeutic research aimed at treating both OA and RA. This study underscores the significance of leveraging bioinformatics approaches to unravel complex disease mechanisms, offering a promising avenue for the development of more effective and targeted treatments.

Uncovering the shared neuro-immune-related regulatory mechanisms between spinal cord injury and osteoarthritis

Adults with spinal cord injury (SCI), a destructive neurological injury, have a significantly higher incidence of osteoarthritis (OA), a highly prevalent chronic joint disorder. This study aimed to dissect the neuroimmune-related regulatory mechanisms of SCI and OA using bioinformatics analysis. Using microarray data from the Gene Expression Omnibus database, differentially expressed genes (DEGs) were screened between SCI and sham samples and between OA and control samples. Common DEGs were used to construct a protein-protein interaction (PPI) network. Weighted gene co-expression network analysis (WGCNA) was used to mine SCI- and OA-related modules. Shared miRNAs were identified, and target genes were predicted using the Human MicroRNA Disease Database (HMDD) database. A miRNA-gene-pathway regulatory network was constructed with overlapping genes, miRNAs, and significantly enriched pathways. Finally, the expression of the identified genes and miRNAs was verified using RT-qPCR. In both the SCI and OA groups, 185 common DEGs were identified, and three hub clusters were obtained from the PPI network. WGCNA revealed three SCI-related modules and two OA-related modules. There were 43 overlapping genes between the PPI network clusters and the WGCNA network modules. Seventeen miRNAs shared between patients with SCI and OA were identified. A regulatory network consisting of five genes, six miRNAs, and six signaling pathways was constructed. Upregulation of CD44, TGFBR1, CCR5, and IGF1, while lower levels of miR-125b-5p, miR-130a-3p, miR-16-5p, miR-204-5p, and miR-204-3p in both SCI and OA were successfully verified using RT-qPCR. Our study suggests that a miRNA-gene-pathway network is implicated in the neuroimmune-related regulatory mechanisms of SCI and OA. CD44, TGFBR1, CCR5, and IGF1, and their related miRNAs (miR-125b-5p, miR-130a-3p, miR-16-5p, miR-204-5p, and miR-204-3p) may serve as promising biomarkers and candidate therapeutic targets for SCI and OA.

Efficacy of Anti-Interleukin-1 Therapeutics in the Treatment of Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials from the Years 2000 to 2023

Objectives: This study aimed to evaluate the efficacy of anti-interleukin-1 therapeutics for treating knee osteoarthritis (KOA). Our research included interleukin-1 (IL-1) inhibitors, IL-1 antibodies and IL-1 receptor antagonists (IL-1 Ras). Methods: We systematically searched PubMed and Mendeley to find randomized control trials (RCTs) or clinical trials (CTs) of anti-interleukin-1 therapeutics in KOA from 2000 to 2023. The outcomes were changes in pain, function and stiffness scores. The research was conducted between November 2023 and January 2024. The risk of bias was assessed using Cochrane Risk of Bias tool RoB 2. Results: Analysis of the nine included studies showed a statistically significant difference in terms of the pain relief group (SMD = -0.20, 95% CI: -0.39 to -0.01, p = 0.0348), physical function improvement (SMD = -0.20, 95% CI: -0.39 to 0.00, p = 0.0479) and stiffness reduction (SMD = -0.22, 95% CI: -0.43 to 0.00, p = 0.0475) between anti-IL-1 therapeutics and placebo or nonsteroidal anti-inflammatory drugs (NSAIDs). However, when we separately analysed placebo and NSAIDs subgroups, the statistical significance was observed only in the placebo group. Our article was limited by the quality of the included RCTs. Two of the included trials were of poor methodological quality, and five showed selective reporting. Conclusions: The results of our study suggest that anti-IL-1 therapeutics might have better efficacy in KOA treatment than placebo or NSAIDs; yet, taking into account the limited availability of studies and data concerning anti-IL-1 in osteoarthritis treatment, we think that more high-quality RCTs on this subject are needed.

Role of crosstalk between synovial cells and chondrocytes in osteoarthritis (Review)

Osteoarthritis (OA) is a low-grade, nonspecific inflammatory disease that affects the entire joint. This condition is characterized by synovitis, cartilage erosion, subchondral bone defects, and subpatellar fat pad damage. There is mounting evidence demonstrating the significance of crosstalk between synovitis and cartilage destruction in the development of OA. To comprehensively explore the phenotypic alterations of synovitis and cartilage destruction, it is important to elucidate the crosstalk mechanisms between chondrocytes and synovial cells. Furthermore, the updated iteration of single-cell sequencing technology reveals the interaction between chondrocyte and synovial cells. In the present review, the histological and pathological alterations between cartilage and synovium during OA progression are described, and the mode of interaction and molecular mechanisms between synovial cells and chondrocytes in OA, both of which affect the OA process mainly by altering the inflammatory environment and cellular state, are elucidated. Finally, the current OA therapeutic approaches are summarized and emerging therapeutic targets are reviewed in an attempt to provide potential insights into OA treatment.

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

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

Is RANKL a potential molecular target in osteoarthritis?

OBJECTIVE

Osteoarthritis (OA) is a disease of joints, in which the bone under the articular cartilage undergoes increased remodelling activity. The question is whether a better understanding of the causes and mechanisms of bone remodelling can predict disease-modifying treatments.

DESIGN

This review summarises the current understanding of the aetiology of OA, with an emphasis on events in the subchondral bone (SCB), and the cells and cytokines involved, to seek an answer to this question.

RESULTS

SCB remodelling across OA changes the microstructure of the SCB, which alters the load-bearing properties of the joint and seems to have an important role in the initiation and progression of OA. Bone remodelling is tightly controlled by numerous cytokines, of which Receptor Activator of NFκB ligand (RANKL) and osteoprotegerin are central factors in almost all known bone conditions. In terms of finding therapeutic options for OA, an important question is whether controlling the rate of SCB remodelling would be beneficial. The role of RANKL in the pathogenesis and progression of OA and the effect of its neutralisation remain to be clarified.

CONCLUSIONS

This review further makes the case for SCB remodelling as important in OA and for additional study of RANKL in OA, both its pathophysiological role and its potential as an OA disease target.

New therapeutic strategies in osteoarthritis

Osteoarthritis (OA) is the most prevalent arthritis-type and is a major contributor to chronic joint pain, impaired physical function, and limited mobility. By the end of 2020, a total of 595 million, equal to 7·6% of the global population, had OA; this figure is expected to rise exponentially by 2050. Even while the disorder's intricate pathophysiology is starting to appear intelligible, we are yet to have a cure for the disorder. OA is typically managed with traditional palliative measures, such as topical and systemic analgesics, including non-steroidal anti-inflammatory drugs, therapeutic exercise, and braces. Sometimes, intra-articular glucocorticoids, viscosupplementation, or regenerative interventions provide short-term pain relief and functional improvement; some may require arthroplasty. Researchers continue their efforts to unveil a new therapeutic target to be effective in OA that modifies symptoms and arrests disease progression as well. In the present literature review, insights into new therapeutic strategies in OA, for example, liposome-based dexamethasone, microspore-based triamcinolone, nerve growth factor antagonist, anti-ADAMTS-5 (A Disintegrin And Metalloproteinase Thrombospoidin Motifs - 5), pentosan polysulfate sodium, allogeneic stem cells, C-C chemokine receptor type-4 (CCR4) ligand 17 inhibitor, Wnt-signaling inhibitor, and anti-obesity medications are provided.

Syndecans, Exostosins and Sulfotransferases as Potential Synovial Inflammation Moderators in Patients with Hip Osteoarthritis

The gradual deterioration of articular cartilage was thought to be the central event in osteoarthritis (OA), but recent studies demonstrated the importance of low-grade synovitis in the progression of OA. The Syndecan (SDC) family of membrane proteoglycans is known to be involved in the regulation of inflammation, but there is limited evidence considering the role of syndecans in OA synovitis. Our study aimed to investigate the hip OA synovial membrane expression patterns of SDC1, SDC2 and SDC4, as well as exostosins and sulfotransferases (enzymes involved in the polymerisation and modification of syndecans' heparan sulphate chains). Synovial membrane samples of patients with OA (24) were divided into two groups according to their Krenn synovitis score severity. The immunohistochemical expressions of SDC1, SDC2, SDC4, EXT1, EXT2, NDST1 and NDST2 in synovial intima and subintima were then analysed and compared with the control group (patients with femoral neck fracture). According to our study, the immunoexpression of SDC1, NDST1 and EXT2 is significantly increased in the intimal cells of OA synovial membrane in patients with lower histological synovitis scores and SDC4 in patients with higher synovitis scores, in comparison with non-OA controls. The difference in the expression of SDC2 among the OA and non-OA groups was insignificant. SDC1, SDC4, NDST1 and EXT2 seem to be involved as inflammation moderators in low-grade OA synovitis and, therefore, should be further investigated as potential markers of disease progression and therapeutic goals.

Insights into the Roles of Natural Killer Cells in Osteoarthritis

Osteoarthritis (OA) is now widely acknowledged as a low-grade inflammatory condition, in which the intrinsic immune system plays a significant role in its pathogenesis. While the involvement of macrophages and T cells in the development of OA has been extensively reviewed, recent research has provided mounting evidence supporting the crucial contribution of NK cells in both the initiation and advancement of OA. Accumulated evidence has emerged in recent years indicating that NK cells play a critical role in OA development and progression. This review will outline the ongoing understanding of the utility of NK cells in the etiology of OA, focusing on how NK cells interact with chondrocytes, synoviocytes, osteoclasts, and other immune cells to influence the course of OA disease.

Usability and preliminary effectiveness of an app-based physical activity and education program for people with hip or knee osteoarthritis - a pilot randomized controlled trial

BACKGROUND

Hip and knee osteoarthritis (OA) are highly prevalent worldwide. The guidelines recommend physical activity and education as the core treatments for osteoarthritis. Digital health has the potential to engage people in physical activity and disease management. Therefore, we conducted a pilot trial to assess the usability and preliminary effectiveness of an app-based physical activity and education program (Join2Move) compared to usual care for people with hip and/or knee OA in Germany.

METHODS

A randomized controlled pilot study was conducted. Individuals with diagnosed or self-reported knee and hip OA were included. Allocation to the intervention or control group was randomized. The intervention group received the Join2Move program. The Join2Move program was previously developed as a website and evaluated in the Netherlands. For the current study, the program was translated and adapted to the German context and adjusted from a website to an app. The control group received usual care. The primary outcomes were usability and preliminary effectiveness (pain and physical functioning). Measurements were taken at baseline and at twelve weeks. The data analysis was performed using SPSS (IBM SPSS Statistics 29.0).

RESULTS

Sixty participants, with a mean age of 61.9 (SD ± 7.2) years, were allocated to the intervention (n = 32) or the control group (n = 28) and included in the analysis. The majority of participants had knee OA (68%), and 12% had hip and knee OA. The dropout rate was n = 11 (18%). No adverse events were reported. Usability was rated as acceptable (mean System Usability Scale = 71.3/100) with a wide range (32.5 to 100). Statistically significant between-group differences were found only for pain (mean difference 8.52 (95% CI 1.01 to 16.04), p = 0.027).

CONCLUSIONS

Join2Move demonstrated acceptable usability. The preliminary results of the pilot trial indicate the potential of a stand-alone app for the treatment of patients with hip or knee OA. However, the acceptable usability of Join2Move limits its recommendation for everyone. There appears to be room for improvement in app usability and in identifying patients for whom the app is suitable and the right time to use a stand-alone app.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00027164 .

Metabolomic profiles of cartilage and bone reflect tissue type, radiography-confirmed osteoarthritis, and spatial location within the joint

Osteoarthritis is the most common chronic joint disease, characterized by the abnormal remodeling of joint tissues including articular cartilage and subchondral bone. However, there are currently no therapeutic drug targets to slow the progression of disease because disease pathogenesis is largely unknown. Thus, the goals of this study were to identify metabolic differences between articular cartilage and subchondral bone, compare the metabolic shifts in osteoarthritic grade III and IV tissues, and spatially map metabolic shifts across regions of osteoarthritic hip joints. Articular cartilage and subchondral bone from 9 human femoral heads were obtained after total joint arthroplasty, homogenized and metabolites were extracted for liquid chromatography-mass spectrometry analysis. Metabolomic profiling revealed that distinct metabolic endotypes exist between osteoarthritic tissues, late-stage grades, and regions of the diseased joint. The pathways that contributed the most to these differences between tissues were associated with lipid and amino acid metabolism. Differences between grades were associated with nucleotide, lipid, and sugar metabolism. Specific metabolic pathways such as glycosaminoglycan degradation and amino acid metabolism, were spatially constrained to more superior regions of the femoral head. These results suggest that radiography-confirmed grades III and IV osteoarthritis are associated with distinct global metabolic and that metabolic shifts are not uniform across the joint. The results of this study enhance our understanding of osteoarthritis pathogenesis and may lead to potential drug targets to slow, halt, or reverse tissue damage in late stages of osteoarthritis.

Nociplastic pain mechanisms and toll-like receptors as promising targets for its management

ABSTRACT

Nociplastic pain, characterized by abnormal pain processing without an identifiable organic cause, affects a significant portion of the global population. Unfortunately, current pharmacological treatments for this condition often prove ineffective, prompting the need to explore new potential targets for inducing analgesic effects in patients with nociplastic pain. In this context, toll-like receptors (TLRs), known for their role in the immune response to infections, represent promising opportunities for pharmacological intervention because they play a relevant role in both the development and maintenance of pain. Although TLRs have been extensively studied in neuropathic and inflammatory pain, their specific contributions to nociplastic pain remain less clear, demanding further investigation. This review consolidates current evidence on the connection between TLRs and nociplastic pain, with a specific focus on prevalent conditions like fibromyalgia, stress-induced pain, sleep deprivation-related pain, and irritable bowel syndrome. In addition, we explore the association between nociplastic pain and psychiatric comorbidities, proposing that modulating TLRs can potentially alleviate both pain syndromes and related psychiatric disorders. Finally, we discuss the potential sex differences in TLR signaling, considering the higher prevalence of nociplastic pain among women. Altogether, this review aims to shed light on nociplastic pain, its underlying mechanisms, and its intriguing relationship with TLR signaling pathways, ultimately framing the potential therapeutic role of TLRs in addressing this challenging condition.

The evolving landscape of gene therapy strategies for the treatment of osteoarthritis

OBJECTIVES

Significant advances have been made in our understanding of osteoarthritis (OA) pathogenesis; however, no disease-modifying therapies have been identified. This review will summarize the gene therapy landscape, its initial successes for OA, and possible challenges using recent studies and examples of gene therapies in clinical trials.

DESIGN

This narrative review has three major sections: 1) vector systems for OA gene therapy, 2) current and emerging targets for OA gene therapy, and 3) considerations and future directions.

RESULTS

Gene therapy is the strategy by which nucleic acids are delivered to treat and reverse disease progression. Specificity and prolonged expression of these nucleic acids are achieved by manipulating promoters, genes, and vector systems. Certain vector systems also allow for the development of combinatorial nucleic acid strategies that can be delivered in a single intraarticular injection - an approach likely required to treat the complexity of OA pathogenesis. Several viral and non-viral vector-based gene therapies are in clinical trials for OA, and many more are being evaluated in the preclinical arena.

CONCLUSIONS

In a post-coronavirus disease 2019 (COVID-19) era, the future of gene therapy for OA is certainly promising; however, the majority of preclinical validation continues to focus heavily on post-traumatic models and changes in only cartilage and subchondral bone. To ensure successful translation, new candidates in the preclinical arena should be examined against all joint tissues as well as pain using diverse models of injury-, obesity-, and age-induced disease. Lastly, consideration must be given to strategies for repeat administration and the cost of treatment owing to the chronic nature of OA.

Potential therapeutic strategies for osteoarthritis via CRISPR/Cas9 mediated gene editing

Osteoarthritis (OA) is an incapacitating and one of the most common physically degenerative conditions with an assorted etiology and a highly complicated molecular mechanism that to date lacks an efficient treatment. The capacity to design biological networks and accurately modify existing genomic sites holds an apt potential for applications across medical and biotechnological sciences. One of these highly specific genomes editing technologies is the CRISPR/Cas9 mechanism, referred to as the clustered regularly interspaced short palindromic repeats, which is a defense mechanism constituted by CRISPR associated protein 9 (Cas9) directed by small non-coding RNAs (sncRNA) that bind to target DNA through Watson-Crick base pairing rules where subsequent repair of the target DNA is initiated. Up-to-date research has established the effectiveness of the CRISPR/Cas9 mechanism in targeting the genetic and epigenetic alterations in OA by suppressing or deleting gene expressions and eventually distributing distinctive anti-arthritic properties in both in vitro and in vivo osteoarthritic models. This review aims to epitomize the role of this high-throughput and multiplexed gene editing method as an analogous therapeutic strategy that could greatly facilitate the clinical development of OA-related treatments since it's reportedly an easy, minimally invasive technique, and a comparatively less painful method for osteoarthritic patients.

Three decades of advancements in osteoarthritis research: insights from transcriptomic, proteomic, and metabolomic studies

OBJECTIVE

Osteoarthritis (OA) is a complex disease involving contributions from both local joint tissues and systemic sources. Patient characteristics, encompassing sociodemographic and clinical variables, are intricately linked with OA rendering its understanding challenging. Technological advancements have allowed for a comprehensive analysis of transcripts, proteomes and metabolomes in OA tissues/fluids through omic analyses. The objective of this review is to highlight the advancements achieved by omic studies in enhancing our understanding of OA pathogenesis over the last three decades.

DESIGN

We conducted an extensive literature search focusing on transcriptomics, proteomics and metabolomics within the context of OA. Specifically, we explore how these technologies have identified individual transcripts, proteins, and metabolites, as well as distinctive endotype signatures from various body tissues or fluids of OA patients, including insights at the single-cell level, to advance our understanding of this highly complex disease.

RESULTS

Omic studies reveal the description of numerous individual molecules and molecular patterns within OA-associated tissues and fluids. This includes the identification of specific cell (sub)types and associated pathways that contribute to disease mechanisms. However, there remains a necessity to further advance these technologies to delineate the spatial organization of cellular subtypes and molecular patterns within OA-afflicted tissues.

CONCLUSIONS

Leveraging a multi-omics approach that integrates datasets from diverse molecular detection technologies, combined with patients' clinical and sociodemographic features, and molecular and regulatory networks, holds promise for identifying unique patient endophenotypes. This holistic approach can illuminate the heterogeneity among OA patients and, in turn, facilitate the development of tailored therapeutic interventions.

Comparison studies identify mesenchymal stromal cells with potent regenerative activity in osteoarthritis treatment

Osteoarthritis affects 15% of people over 65 years of age. It is characterized by articular cartilage degradation and inflammation, leading to joint pain and disability. Osteoarthritis is incurable and the patients may eventually need joint replacement. An emerging treatment is mesenchymal stromal cells (MSCs), with over two hundred clinical trials being registered. However, the outcomes of these trials have fallen short of the expectation, due to heterogeneity of MSCs and uncertain mechanisms of action. It is generally believed that MSCs exert their function mainly by secreting immunomodulatory and trophic factors. Here we used knee osteoarthritis mouse model to assess the therapeutic effects of MSCs isolated from the white adipose or dermal adipose tissue of Prrx1-Cre; R26tdTomato mice and Dermo1-Cre; R26tdTomato mice. We found that the Prrx1-lineage MSCs from the white adipose tissues showed the greatest in vitro differentiation potentials among the four MSC groups and single cell profiling showed that the Prrx1-lineage MSCs contained more stem cells than the Dermo1 counterpart. Only the Prrx1-lineage cells isolated from white adipose tissues showed long-term therapeutic effectiveness on early-stage osteoarthritis models. Mechanistically, Prrx1-lineage MSCs differentiated into Col2+ chondrocytes and replaced the damage cartilage, activated Col1 expressing in resident chondrocytes, and inhibited synovial inflammation. Transcriptome analysis showed that the articular chondrocytes derived from injected MSCs expressed immunomodulatory cytokines, trophic factors, and chondrocyte-specific genes. Our study identified a MSC population genetically marked by Prrx1 that has great multipotentiality and can differentiate into chondrocytes to replace the damaged cartilage.

Current Evidence Using Pulsed Electromagnetic Fields in Osteoarthritis: A Systematic Review

(1) Background: Osteoarthritis (OA) significantly impacts patients' quality of life and negatively affects public healthcare costs. The aim of this systematic review is to identify the effectiveness of pulsed electromagnetic fields (PEMFs) in OA treatment across different anatomical districts, determining pain reduction and overall improvement in the patient's quality of life. (2) Methods: In this systematic review following PRISMA guidelines, PubMed and Google Scholar were searched for randomized controlled trials involving patients with osteoarthritis undergoing PEMF therapy. Seventeen studies (1197 patients) were included. (3) Results: PEMF therapy demonstrated positive outcomes across various anatomical districts, primarily in knee osteoarthritis. Pain reduction, assessed through VAS and WOMAC scores, showed significant improvement (60% decrease in VAS, 42% improvement in WOMAC). The treatment duration varied (15 to 90 days), with diverse PEMF devices used. Secondary outcomes included improvements in quality of life, reduced medication usage, and enhanced physical function. (4) Conclusions: Diverse PEMF applications revealed promising results, emphasizing pain reduction and improvement in the quality of life of patients. The variability in the treatment duration and device types calls for further investigation. This review informs future research directions and potential advancements in optimizing PEMF therapies for diverse osteoarthritic manifestations.

Metabolomic Profiles and Pathways in Osteoarthritic Human Cartilage: A Comparative Analysis with Healthy Cartilage

Osteoarthritis (OA) is a chronic joint disease with heterogenous metabolic pathology. To gain insight into OA-related metabolism, metabolite extracts from healthy (n = 11) and end-stage osteoarthritic cartilage (n = 35) were analyzed using liquid chromatography-mass spectrometry metabolomic profiling. Specific metabolites and metabolic pathways, including lipid and amino acid pathways, were differentially regulated in osteoarthritis-derived and healthy cartilage. The detected alterations in amino acids and lipids highlighted key differences in bioenergetic resources, matrix homeostasis, and mitochondrial alterations in OA-derived cartilage compared to healthy cartilage. Moreover, the metabolomic profiles of osteoarthritic cartilage separated into four distinct endotypes, highlighting the heterogenous nature of OA metabolism and the diverse landscape within the joint in patients. The results of this study demonstrate that human cartilage has distinct metabolomic profiles in healthy and end-stage OA patients. By taking a comprehensive approach to assess metabolic differences between healthy and osteoarthritic cartilage and within osteoarthritic cartilage alone, several metabolic pathways with distinct regulation patterns were detected. Additional investigation may lead to the identification of metabolites that may serve as valuable indicators of disease status or potential therapeutic targets.

Effectiveness and safety of drugs for obesity

Recent publicity around the use of new antiobesity medications (AOMs) has focused the attention of patients and healthcare providers on the role of pharmacotherapy in the treatment of obesity. Newer drug treatments have shown greater efficacy and safety compared with older drug treatments, yet access to these drug treatments is limited by providers' discomfort in prescribing, bias, and stigma around obesity, as well as by the lack of insurance coverage. Now more than ever, healthcare providers must be able to discuss the risks and benefits of the full range of antiobesity medications available to patients, and to incorporate both guideline based advice and emerging real world clinical evidence into daily clinical practice. The tremendous variability in response to antiobesity medications means that clinicians need to use a flexible approach that takes advantage of specific features of the antiobesity medication selected to provide the best option for individual patients. Future research is needed on how best to use available drug treatments in real world practice settings, the potential role of combination therapies, and the cost effectiveness of antiobesity medications. Several new drug treatments are being evaluated in ongoing clinical trials, suggesting that the future for pharmacotherapy of obesity is bright.

Cardamonin inhibits osteogenic differentiation by downregulating Wnt/beta-catenin signaling and alleviates subchondral osteosclerosis in osteoarthritic mice

Osteoarthritis (OA) is a common degenerative joint disease, and subchondral osteosclerosis is an important pathological change that occurs in its late stages. Cardamonin (CD) is a natural flavonoid isolated from Alpinia katsumadai that has anti-inflammatory activity. The objectives of this study were to investigate the therapeutic effects and potential mechanism of CD in regulating OA subchondral osteosclerosis at in vivo and in vitro settings. Eight-week-old male C57BL/6J mice were randomly divided into four groups: sham operation, anterior cruciate ligament transection (ACLT)-induced OA model, low-dose and high-dose CD treated ACLT-OA model groups. Histological assessment and immunohistochemical examinations for chondrocyte metabolism-related markers metalloproteinase-13, ADAMTS-4, Col II, and Sox-9 were performed. Microcomputed tomography was used to assess the sclerosis indicators in subchondral bone. Further, MC3T3-E1 (a mouse calvarial preosteoblast cell line) cells were treated with various concentrations of CD to reveal the influence and potential molecular pathways of CD in osteogenic differentiations. Animal studies suggested that CD alleviated the pathological changes in OA mice such as maintaining integrity and increasing the thickness of hyaline cartilage, decreasing the thickness of calcified cartilage, decreasing the Osteoarthritis Research Society International score, regulating articular cartilage metabolism, and inhibiting subchondral osteosclerosis. In vitro investigation indicated that CD inhibited alkaline phosphatase expression and production of calcium nodules during osteogenic differentiation of MC3T3-E1 cells. In addition, CD inhibited the expression of osteogenic differentiation-related indicators and Wnt/β-catenin pathway-related proteins. In conclusion, CD inhibits osteogenic differentiation by downregulating Wnt/β-catenin signaling and alleviating subchondral osteosclerosis in a mouse model of OA.

Plasma microRNA-320c as a Potential Biomarker for the Severity of Knee Osteoarthritis and Regulates cAMP Responsive Element Binding Protein 5 (CREB5) in Chondrocytes

Objective

Osteoarthritis (OA) is a commonly known prevalent joint disease, with limited therapeutic methods. This study aimed to investigate the expression of plasma microRNA-320c (miR-320c) in patients with knee OA and to explore the clinical value and potential mechanism of miR-320c in knee OA.

Methods

Forty knee OA patients and 20 healthy controls were enrolled. The levels of plasma miR-320c and plasma inflammatory cytokines were measured by real-time PCR or ELISA. Correlations of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and cytokine levels with the miR-320c expression level were evaluated by Pearson correlation analysis. Then, a receiver operating characteristic (ROC) curve was drawn to analyse the diagnostic value of miR-320c in OA. Finally, the interaction of miR-320c and cAMP responsive element binding protein 5 (CREB5) was determined using a luciferase reporter assay, and the effect of CREB5 on the cAMP pathway was assessed.

Results

The expression level of plasma miR-320c was significantly higher in OA patients than in healthy controls (p  < 0.05). The increased plasma miR-320c level was positively correlated with the WOMAC score (r = 0.796, p  < 0.001) and the plasma interleukin (IL)-1β (r = 0.814, p  < 0.001) and IL-6 (r = 0.695, p  < 0.001) levels in patients with OA. ROC curve analysis demonstrated the relatively high diagnostic accuracy of plasma miR-320c for OA. Furthermore, the luciferase reporter assay results showed that miR-320c regulates CREB5 expression by binding to the CREB5 3'-untranslated region. Moreover, suppression of CREB5 significantly reduced the expression levels of c-fos and c-jun.

Conclusion

Our results indicate that plasma miR-320c may serve as a potential novel predictor of the severity of knee OA and that miR-320c may play an important role in the pathogenesis of OA through inhibiting the cAMP pathway by targeting CREB5.

Advances in the study of mitophagy in osteoarthritis

Osteoarthritis (OA), characterized by cartilage degeneration, synovial inflammation, and subchondral bone remodeling, is among the most common musculoskeletal disorders globally in people over 60 years of age. The initiation and progression of OA involves the abnormal metabolism of chondrocytes as an important pathogenic process. Cartilage degeneration features mitochondrial dysfunction as one of the important causative factors of abnormal chondrocyte metabolism. Therefore, maintaining mitochondrial homeostasis is an important strategy to mitigate OA. Mitophagy is a vital process for autophagosomes to target, engulf, and remove damaged and dysfunctional mitochondria, thereby maintaining mitochondrial homeostasis. Cumulative studies have revealed a strong association between mitophagy and OA, suggesting that the regulation of mitophagy may be a novel therapeutic direction for OA. By reviewing the literature on mitophagy and OA published in recent years, this paper elaborates the potential mechanism of mitophagy regulating OA, thus providing a theoretical basis for studies related to mitophagy to develop new treatment options for OA.

The association between genetic polymorphisms of matrix metalloproteinases and knee osteoarthritis: A systematic review and meta-analysis

AIM

To investigate the linkage of matrix metalloproteinase (MMP) gene polymorphisms with the pathogenesis of knee osteoarthritis (OA).

METHODS

This meta-analysis study systematically retrieved relevant studies from PubMed, Embase, the Cochrane Central, Wanfang Data, CNKI, and SinoMed up to November 2020. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the association between MMP gene polymorphisms and OA.

RESULTS

A total of nine case-control studies comprising 1719 knee OA patients and 1904 controls were included in this meta-analysis. The results revealed that MMP-1-1607 (rs1799750) 1G/2G polymorphism was not significantly associated with knee OA risk in four genetic models (OR (95% CI): allele model: 0.89 (0.57, 1.40), p = .615); dominant mode: 0.82 (0.47, 1.44), p = .486; recessive model: 0.88 (0.49, 1.57), p = .659; homozygote model: 0.79 (0.34, 1.82), p = .576. The association was significant for dominant model of MMP-3 C/T: 1.54 (1.10-2.15), p = .013, especially in Asian ethnicity (1.63 (1.11, 2.39), p = .013). Variants of MMP-13 C/T polymorphism were associated with increased risk of knee OA development based on dominant model: 1.56 (1.19, 2.06), p = .001 and homozygote model: 2.12 (1.44, 3.13), p < .001, and there were significant associations between MMP-13 C/T polymorphism and knee OA risk in Asian ethnicity under different genetic models (all p > .05).

CONCLUSIONS

Present evidence suggested that the gene polymorphisms of MMP-1-1607 1G/2G may not be associated with the risk of OA. But, the dominant model of MMP-3 and MMP-13 polymorphisms in Asian ethnicity was significantly correlated with knee OA.

Mechanisms of pain in aging and age-related conditions: Focus on caregivers

Pain is a complex, subjective experience that can significantly impact quality of life, particularly in aging individuals, by adversely affecting physical and emotional well-being. Whereas acute pain usually serves a protective function, chronic pain is a persistent pathological condition that contributes to functional deficits, cognitive decline, and emotional disturbances in the elderly. Despite substantial progress that has been made in characterizing age-related changes in pain, complete mechanistic details of pain processing mechanisms in the aging patient remain unknown. Pain is particularly under-recognized and under-managed in the elderly, especially among patients with Alzheimer's disease (AD), Alzheimer's disease-related dementias (ADRD), and other age-related conditions. Furthermore, difficulties in assessing pain in patients with AD/ADRD and other age-related conditions may contribute to the familial caregiver burden. The purpose of this article is to discuss the mechanisms and risk factors for chronic pain development and persistence, with a particular focus on age-related changes. Our article also highlights the importance of caregivers working with aging chronic pain patients, and emphasizes the urgent need for increased legislative awareness and improved pain management in these populations to substantially alleviate caregiver burden.