Defining and mapping the person with osteoarthritis for population studies and public health

Efficacy and safety of SKCPT in patients with knee osteoarthritis: A multicenter, randomized, double-blinded, active-controlled phase III clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoarthritis (OA) is the most prevalent type of arthritis worldwide and a leading cause of years lost to pain and disability. Among the current pharmacological treatments for OA, symptomatic slow-acting drugs for OA (SYSADOA) induce pain relief and aim to improve joint function by relieving inflammation while causing fewer gastrointestinal and cardiovascular adverse events than non-steroidal anti-inflammatory drugs (NSAIDs). SKCPT is a herbal SYSADOA formulated from Clematis mandshurica, Trichosanthes kirilowii, and Prunella vulgaris powdered extracts. This preparation has been shown to induce cartilage protection and anti-inflammatory effects in preclinical studies and inhibit glycosaminoglycan degradation and catabolic gene expression in human OA chondrocytes and cartilage.

AIM OF THE STUDY

We aimed to evaluate the non-inferiority of SKCPT to celecoxib and safety for treating knee OA.

MATERIALS AND METHODS

This multicenter, randomized, double-blind, phase III clinical trial enrolled adults with primary knee OA who were randomized (1:1) to SKCPT 300 mg twice daily or celecoxib 200 mg once daily for 12 weeks.

RESULTS

In total, 278 patients were assigned to treatment (SKCPT, 136; celecoxib, 142) for approximately 12 weeks. The primary endpoint was the mean change of Korean Western Ontario and McMaster Universities Osteoarthritis Index (K-WOMAC) pain subscale scores from baseline to Day 84. The mean change (least squares [LS] mean ± standard error) from baseline to Day 84 was -23.74 ± 1.48 for SKCPT and -25.88 ± 1.44 for celecoxib. The two-sided 95% confidence interval of the difference (LS mean) between groups was [-1.94, 6.20], confirming that the upper limit was less than the non-inferiority margin of 10. Additionally, there were no significant differences in the secondary endpoints (mean changes of K-WOMAC pain, physical, stiffness subscale, and total score, and the frequency and number of doses of rescue medications) between groups at all time points. Differences between groups in adverse events and adverse drug reactions were not significant, and no serious adverse events occurred.

CONCLUSIONS

SKCPT efficacy was non-inferior, and its safety profile was similar, to celecoxib. Building on previous results showing that SYSADOA reduce NSAID intake, the present results suggest that the SYSADOA SKCPT could effectively replace NSAIDs in knee OA treatment while avoiding long-term side effects.

Identification of a novel disulfidptosis-related gene signature in osteoarthritis using bioinformatics analysis and experimental validation

Osteoarthritis (OA) is a degenerative bone disease characterized by the destruction of joint cartilage and synovial inflammation, involving intricate immune regulation processes. Disulfidptosis, a novel form of programmed cell death, has recently been identified; however, the effects and roles of disulfidptosis-related genes (DR-DEGs) in OA remain unclear. We obtained six OA datasets from the GEO database, using four as training sets and two as validation sets. Differential expression analysis was employed to identify DR-DEGs, and unique molecular subtypes of OA were constructed based on these DR-DEGs. Subsequently, the immune microenvironment of OA patients was comprehensively analyzed using the "CIBERSORT" algorithm for immune infiltration. Various machine learning algorithms were utilized to screen characteristic DR-DEGs, and nomogram models and ROC curves were built based on these genes. The scRNA dataset (GSE169454) was used to classify chondrocytes in OA samples into distinct cell types, further exploring the gene distribution and correlation of characteristic DR-DEGs with specific cell subpopulations. Moreover, the expression levels of four characteristic DR-DEGs were validated through OA cell models and rat models. In our study, we identified 10 DR-DEGs with significant differences in expression within OA samples. Based on these DR-DEGs, two distinct molecular subtypes were recognized (cluster 1 and 2). ZNF484 and NDUFS1 were found to be significantly overexpressed in subtype 1, while the infiltration abundance of activated mast cells was markedly elevated in subtype 2. Moreover, significant differences were observed in the infiltration proportions of 11 immune cell types between OA and control samples, with 9 DR-DEGs demonstrating substantial correlations with immune cell infiltration levels. Further analysis of the scRNA dataset revealed that SLC3A2 and NDUFC1 were predominantly expressed in the preHTC subpopulation. All 10 DR-DEGs exhibited notably higher expression in the EC subpopulation across various cell types. The proportion of EC subgroups with high SLC3A2 expression increased, mainly enriching pathways related to inflammation, such as the IL-17 signaling pathway and TGF-beta signaling pathway. Using machine learning, we identified four characteristic DR-DEGs, which, in combination with the nomogram and ROC models, demonstrated promising performance in the diagnosis of OA. Additionally, in vivo validation confirmed a significant elevation of PPM1F expression in OA models. This study identified DR-DEGs as potential biomarkers for the diagnosis and classification of OA and provided a preliminary understanding of their role in the immune microenvironment. However, further experimental and clinical studies are required to validate their diagnostic value and therapeutic potential.

Lycopodium japonicum Thunb. inhibits chondrocyte apoptosis, senescence and inflammation in osteoarthritis through STING/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoarthritis (OA) is a degenerative disease, its characteristic lies in the inflammation and extracellular matrix (ECM) degradation, can lead to significant personal disability and social burden. Lycopodium japonicum Thunb. (LJT) is a lycopinaceae plant with anti-inflammatory and analgesic effects. In traditional Oriental medicine, LJT is commonly used to treat a variety of conditions, including osteoarthritis and low back pain.

AIM OF THE STUDY

To investigate the anti-apoptotic, anti-inflammatory and anti-senescence properties of LJT in IL-1β-induced mouse chondrocytes, and to clarify the underlying mechanisms involved. In addition, the study also examined the effects of LJT by establishing a mouse model of osteoarthritis. The ultimate goal is to identify the mechanism of LJT as an anti-osteoarthritis agent.

MATERIALS AND METHODS

In this research, molecular docking and network pharmacology analysis were performed to identify the latent pathways and key targets of LJT action. The CCK-8 kit was used to evaluate LJT's effect on chondrocyte viability. Western blotting, Immunofluorescence, TUNEL staining kit, and SA-β-gal staining were employed to verify LJT's impact on chondrocytes. Additionally, SO, HE, and Immunohistochemical were utilized to assess LJT's effects on osteoarthritis in mice. In vitro and in vivo experiments were performed to verify the potential mechanism of LJT in OA.

RESULTS

Network pharmacology analysis revealed that AKT1, PTGS2, and ESR1 were the key candidate targets for the treatment of OA with LJT. The results of molecular docking indicated that AKT1 exhibited a low binding affinity to the principal constituents of LJT. Hence, we have chosen STING, an upstream regulator of PTGS2, as our target for investigation. Molecular docking revealed that sitosterol, formononetin, stigmasterol and alpha-Onocerin, the main components of LJT, have good binding activity with STING. In vitro experiments showed that LJT inhibited IL-1β-mediated secretion of inflammatory mediators, apoptosis and senescence of chondrocytes. The results showed that LJT abolished cartilage degeneration induced by unstable medial meniscus (DMM) in mice. Mechanism research has shown that LJT by inhibiting the STING/NF-κB signaling pathways, down-regulating the NF-κB activation, so as to inhibit the development of OA.

CONCLUSION

LJT reversed the progression of OA by inhibiting inflammation, apoptosis and senescence in animal models and chondrocytes. The effects of LJT are mediated through the STING/NF-κB pathway.

Basal metabolic rate mediates the causal relationship between gut microbiota and osteoarthritis: a two-step bidirectional Mendelian randomization study

Background

The relationship between gut microbiota and osteoarthritis (OA) occurrence remains unclear. Existing research needs to clearly understand how basal metabolic rate (BMR) regulates this relationship. Therefore, using a two-step bidirectional Mendelian Randomization approach, our study aims to investigate whether BMR levels mediate the causal relationship between gut microbiota and OA.

Methods

In this study, we examined publicly available summary statistics from Genome-Wide Association Studies (GWAS) to determine the correlation between gut microbiota and OA. The analysis included one primary dataset and two secondary datasets. Initially, a two-step, two-sample, and reverse MR analysis was performed to identify the causal relationship between gut microbiota and OA. Subsequently, a two-step MR analysis revealed that the relationship between microbiota and OA is mediated by BMR. Sensitivity analyses confirmed the robustness of the study results.

Results

In our analysis of the primary dataset, we discovered a positive correlation between three taxa and the outcome of OA, and eight taxa exhibited a negative correlation with the OA outcome. Through comparisons with the secondary dataset and multiple testing corrections, we found a negative association between the class Actinobacteria (OR=0.992886277, p-value = 0.003) and the likelihood of OA occurrence. Notably, knee osteoarthritis (KOA) and hip osteoarthritis (HOA) had a strong negative correlation (OR = 0.927237553/0.892581219). Our analysis suggests that BMR significantly mediates the causal pathway from Actinobacteria to OA, with a mediated effect of 2.59%. Additionally, BMR mediates 3.98% of the impact in the path from the order Bifidobacteriales and the family Bifidobacteriaceae to OA. Besides these findings, our reverse analysis did not indicate any significant effect of OA on gut microbiota or BMR.

Conclusion

Our research results indicate that an increase in the abundance of specific gut microbial taxa is associated with a reduced incidence of OA, and BMR levels mediate this causal relationship. Further large-scale randomized controlled trials are necessary to validate the causal impact of gut microbiota on the risk of OA. This study provides new insights into the potential prevention of OA by modulating the gut microbiota.

The Potential of Intra-Articular Therapies in Managing Knee Osteoarthritis: A Systematic Review

BACKGROUND

Knee osteoarthritis (KOA) is a common degenerative and progressive joint disorder that negatively influences patients' quality of life. Intra-articular therapies, such as hyaluronic acid (HA) and platelet-rich plasma (PRP), have garnered attention for their potential to manage osteoarthritis OA symptoms effectively. This systematic review aims to identify the effectiveness and safety of HA and PRP treatment modalities in treating KOA.

METHODS

A literature search was conducted across MEDLINE (PubMed), Web of Science Core Collection, and Science Direct Collection Elsevier. Twenty-three randomized controlled trials, cohort studies, and observational studies were included in the review. The selection criteria focused on studies published in English within the last 10 years, involving subjects with KOA treated with intra-articular injections of HA or PRP and reporting on pain, function, or overall treatment efficacy outcomes.

RESULTS

The analysis showed that both HA and PRP significantly improve functionality and reduce pain in KOA patients. High molecular weight HA consistently reduced pain and improved joint mobility in various studies. PRP had better long-term outcomes when combined with HA, leading to greater pain reduction and functional improvement. Both therapies had generally favorable safety profiles, with only minor adverse events reported. However, there were potential biases identified across the studies, such as selection, performance, detection, and reporting biases, which impacted the reliability of the results.

CONCLUSIONS

Intra-articular treatments with HA and PRP show promise in managing knee osteoarthritis, with personalized treatment plans and further research needed to confirm these findings.

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

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

Correlations of characteristics with tissue involvement in knee gouty arthritis: Magnetic resonance imaging analysis

Objective

This study investigates the MRI features of knee gouty arthritis (KGA), examines its relationship with the extent of tissue involvement, and assesses whether risk factors can predict KGA.

Materials and methods

Patients diagnosed with KGA underwent MRI examinations, and two independent observers retrospectively analyzed data from 44 patients (49 knees). These patients were divided into mild and severe groups based on tissue involvement observed during arthroscopy. MRI features were summarized, and the intraclass correlation coefficient evaluated interobserver reproducibility. Single-factor analysis compared clinical indicators and MRI features between groups, while Cramer's V coefficient assessed correlations. Multivariate logistic regression identified predictors of tissue involvement extent, and a ROC curve evaluated diagnostic performance.

Results

Among 49 knees, 18 had mild and 31 had severe tissue involvement. Key MRI features included ligament sketch-like changes, meniscal urate deposition, irregularly serrated cartilage changes, low-signal signs within joint effusion, synovial proliferation, Hoffa's fat pad synovitis, gouty tophi, bone erosion, and bone marrow edema. The interobserver reliability of the MRI features was good. Significant differences (P < 0.05) were observed between the groups for anterior cruciate ligament (ACL) sketch-like changes, Hoffa's fat pad synovitis, and gouty tophi. ACL sketch-like changes (r = 0.309), Hoffa's fat pad synovitis (r = 0.309), and gouty tophi (r = 0.408) were positively correlated with the extent of tissue involvement (P < 0.05). ACL sketch-like changes (OR = 9.019, 95 % CI: 1.364-61.880), Hoffa's fat pad synovitis (OR = 6.472, 95 % CI: 1.041-40.229), and gouty tophi (OR = 5.972, 95 % CI: 1.218-29.276) were identified as independent predictors of tissue involvement extent (P < 0.05). The area under the ROC curve was 0.862, with a sensitivity of 67.70 %, specificity of 94.40 %, and accuracy of 79.14 %.

Conclusion

This comprehensive analysis of MRI features identifies ligament sketch-like changes, meniscal urate deposition, and low-signal signs within joint effusion as characteristic MRI manifestations of KGA. Irregular cartilage changes are valuable for differential diagnosis in young and middle-aged patients. ACL sketch-like changes, Hoffa's fat pad synovitis, and gouty tophi correlate with tissue involvement severity and are critical in predicting and assessing the extent of tissue involvement in KGA.

Predictors, Protective Factors, and Adverse Outcomes of Joint Pain among Malaysian Community-Dwelling Older Adults: Findings from the LRGS-TUA Longitudinal Study

Background: Joint pain has been recognized as one of the major causes of limitations in mobility, functional decline, and consequently declined quality of life in older adults. Hence, this study aimed to identify the predictors, protective factors, and adverse outcomes of joint pain in community-dwelling older adults. Methods: In this Long-term Research Grant Scheme-Towards Useful Ageing (LRGS-TUA) longitudinal study, a total of 1005 older participants aged 60 years and above who were successfully followed up after five years were included in the analysis. The participants self-reported their joint pain status at baseline and during the fifth year. Subsequently, the baseline characteristics were used to predict changes in joint pain status. Adverse outcomes related to joint pain were evaluated based on the participants' joint pain statuses. Results: Results showed that being female, having diabetes mellitus, and higher body mass index were associated with the incidence of joint pain. Meanwhile, increased intake of pantothenic acid and higher levels of blood albumin levels were associated with recovery from joint pain. Participants with persistent joint pain at baseline and follow-up showed higher levels of depression and disability compared to individuals who never experience any joint pain. However, participants who had recovered from joint pain did not differ significantly from those without joint pain at baseline and follow-up in these measures. Conclusions: By identifying the modifiable risk factors, factors associated with recovery, and adverse outcomes related to joint pain, this study adds to current evidence that may contribute to further management strategies for joint pain in older adults.

Research Progress on Injectable Microspheres as New Strategies for the Treatment of Osteoarthritis Through Promotion of Cartilage Repair

Osteoarthritis (OA) is a degenerative disease caused by a variety of factors with joint pain as the main symptom, including fibrosis, chapping, ulcers, and loss of cartilage. Traditional treatment can only delay the progression of OA, and classical delivery system have many side effects. In recent years, microspheres have shown great application prospects in the field of OA treatment. Microspheres can support cells, reproduce the natural tissue microenvironment in vitro and in vivo, and are an efficient delivery system for the release of drugs or biological agents, which can promote cell proliferation, migration, and differentiation. Thus, they have been widely used in cartilage repair and regeneration. In this review, preparation processes, basic materials, and functional characteristics of various microspheres commonly used in OA treatment are systematically reviewed. Then it is introduced surface modification strategies that can improve the biological properties of microspheres and discussed a series of applications of microsphere functionalized scaffolds in OA treatment. Finally, based on bibliometrics research, the research development, future potential, and possible research hotspots of microspheres in the field of OA therapy is systematically and dynamically evaluated. The comprehensive and systematic review will bring new understanding to the field of microsphere treatment of OA.

Exploring the potential extended role of community pharmacy in the management of osteoarthritis: A multi-methods study with pharmacy staff and other healthcare professionals

INTRODUCTION

Osteoarthritis is the commonest form of chronic joint pain, which patients often self-manage before seeking healthcare advice. Patients frequently seek advice from community pharmacies, and a recent policy has recommended integrating community pharmacies into long-term condition pathways. This study explored community pharmacy teams' (CPs) and other healthcare professionals' (HCPs) views on community pharmacies providing an extended role for osteoarthritis management, identifying potential barriers and facilitators to this.

METHODS

A multi-methods study comprising surveys of CPs and other HCPs, followed by qualitative interviews. Descriptive statistics were used in an exploratory analysis of the survey data. Qualitative data were analysed using reflexive thematic analysis and the identified barriers and facilitators were mapped to the Theoretical Domains Framework.

RESULT

CPs and other HCPs in the surveys and interviews reported that an extended role for osteoarthritis management could include: a subjective assessment, explaining the joint problem and its treatment, medication management and support for self-care. There was less consensus on diagnosing the problem as OA and completing an objective assessment. A key facilitator was training to deliver the role, whilst barriers were high workload and lack of access to General Practitioner medical records.

DISCUSSION

Acceptable elements of an extended community pharmacy role for osteoarthritis centre around the provision of information, advice on medication and supported self-management.

CONCLUSION

CPs are well placed to contribute towards evidenced-based osteoarthritis management. Feasibility testing of delivering the extended role is needed and future implementation requires training for CPs and raising public awareness of the extended role.

Disease-modifying agents in osteoarthritis: where are we now and what does the future hold?

Cite this article: Bone Joint Res  2023;12(10):654–656.

Vitamin D and autophagy in knee osteoarthritis: A review

Knee osteoarthritis (KOA), the highly prevalent degenerative disease affecting the joint, perpetually devastates the health of the elderly. Of various mechanisms known to participate in KOA etiology, apoptosis of chondrocytes is widely regarded as the primary cause of cartilage degradation. It has been suggested that the induction of autophagy in chondrocytes could potentially prolong the progression of KOA by modulating intracellular metabolic processes, which may be helpful for ameliorating chondrocyte apoptosis and eventual cartilage degeneration. Autophagy, a physiological process characterized by intracellular self-degradation, has been reportedly implicated in various pathologic conditions including KOA. Interestingly, vitamin D has been shown to regulate autophagy in human chondrocytes through multiple pathways, specifically AMPK/mTOR signaling pathway. This observation underscores the potential of vitamin D as a novel approach for restoring the functionality and survivability of chondrocytes in KOA. Supporting vitamin D's clinical significance, previous studies have demonstrated its substantial involvement in the symptoms and irregular joint morphology observed in KOA patients, strengthening potential therapeutic efficacy of vitamin D in treatment of KOA. Herein, the purpose of this review was to determine the mechanisms underlying the multi-processes of vitamin D implicated in autophagy in several cells including chondrocytes, which would bring unique insights into KOA pathogenesis.

A comparison of the burden of knee osteoarthritis attributable to high body mass index in China and globally from 1990 to 2019

Background

Excess body mass index (BMI) plays a key role in the onset and progression of knee osteoarthritis (knee OA). However, the burden of knee OA attributable to high BMI at the global, Chinese, and regional levels have received far too little attention. The aim of this study is to provide evidence to support the design of policy by investigating long-term trends of years lived with disability (YLDs) for knee OA.

Methods

To illustrate the trends of YLDs for knee OA attributable to high BMI and the temporal trends of the YLDs rate by age, period, and cohort, Joinpoint regression software and age-period-cohort (APC) were used to analyze the YLDs data of knee OA from the Global Burden of Disease (GBD) 2019.

Results

In China, there were 549,963.5 YLDs for knee OA attributable to high BMI in 2019, which had increased by 460.7% since 1990. From 1990 to 2019, age-standardized disability-adjusted life year rate (ASDR) of knee OA attributable to high BMI trended upwards. The average annual percent change (AAPC) of knee OA attributable to high BMI in China and globe were 3.019, 1.419%, respectively. The longitudinal age curve of the APC model showed that the YLDs rates of knee OA due to high BMI increased with age, and YLDs rates were higher among females than males. The period rate ratios (RRs) of knee OA due to high BMI increased significantly. The cohort RRs of knee OA due to high BMI increased among those born between 1900 and 1970. The net drifts of knee OA attributable to high BMI in China and globe were above 1. Compared with global condition, the net drift values of knee OA attributable to high BMI in China was higher. Compared with females, males had higher net drift value. Countries with high socio-demographic index (SDI) have a much higher burden of knee OA caused by high BMI than countries with low SDI.

Conclusion

In China, high BMI is a substantial cause of knee OA, the incidence of which has been increasing since 1990. In addition, women and the elderly are more vulnerable to knee OA caused by high BMI. The Chinese government must take the long-term impact of high BMI on knee OA into account and implement effective public health policies and resort to interventions to reduce the burden as soon as possible.

Physical Therapists' Choices, Views and Agreements Regarding Non-Pharmacological and Non-Surgical Interventions for Knee Osteoarthritis Patients: A Mixed-Methods Study

Objective/Aims

The aims of this study are to collect the most common non-pharmacological and non-surgical interventions used by the Portuguese physical therapists in their knee osteoarthritis patients, and to deeper understand the factors associated to their intervention choices.

Methods

This study incorporated a mixed-methods design. For the quantitative data it was choose an e-survey (with 25 close-end questions, plus general information of the study and a clinical vignette), retrieving sociodemographic and self-reported practice on knee osteoarthritis information. It was analysed response frequencies and associations between variables with logistic regression analyses. For the qualitative data, it was chosen to perform semi-structured interviews in purposefully selected physical therapists to include different sociodemographic factors and survey responses regarding the physical therapists' interventions chosen. After the interviews, the audios were collected, anonymised, transcribed verbatim, and the texts explored by the thematic approach.

Results

From the 277 PTs that shown interest in participating in the study, 120 fully completed the questionnaire and, from those, 10 participated in the interviews. The most chosen interventions included Resistance Exercise, Manual Therapy, Nutrition/Weight Loss, Self-care/Education, Stretching and Aquatic Exercise. Furthermore, it seems that PTs' individual characteristics (age, experience, and clinical reasoning), patient's characteristics (clinical findings and preferences), and work-related factors (facility type, work environment and available resources) are the main actors responsible for an intervention chosen.

Conclusions

In the Portuguese PTs context the most important interventions are Exercise, Manual Therapy, Nutrition/Weight Loss, and Self-care/Education; these interventions chosen may be influenced by PT, patient and work-related factors.

Comprehensive analysis of arachidonic acid metabolism-related genes in diagnosis and synovial immune in osteoarthritis: based on bulk and single-cell RNA sequencing data

BACKGROUND

Osteoarthritis (OA) is one of degenerative-related arthritis, which can be aggravated by low-grade synovitis. It is known that arachidonic acid (AA) dysmetabolism brings OA synovitis. However, the impact of synovial AA metabolism pathway (AMP) related genes on OA remains uncovered.

METHODS

Here, we conducted a comprehensive analysis to explore the impact of AA metabolism genes in OA synovium. We obtained transcriptome expression profiles from three raw datasets related to OA synovium (GSE12021, GSE29746, GSE55235) and identified the hub genes of AA metabolism pathways (AMP) in OA synovium. An OA occurrence diagnostic model was constructed and validated based on the identified hub genes. Then, we explored the correlation between hub gene expression and the immune-related module using CIBERSORT and MCP-counter analysis. The unsupervised consensus clustering analysis and weighted correlation network analysis (WGCNA) were utilized to identify robust clusters of identified genes in each cohort. Moreover, the interaction between the hub genes of AMP and immune cells was elucidated through single-cell RNA (scRNA) analysis by scRNA sequencing data from GSE152815.

RESULTS

We found that the expression of AMP-related genes was up-regulated in OA synovium, and seven hub genes (LTC4S, PTGS2, PTGS1, MAPKAPK2, CBR1, PTGDS, and CYP2U1) were identified. The diagnostic model that combined the identified hub genes showed great clinical validity in diagnosing OA (AUC = 0.979). Moreover, significant associations were noticed between the hub genes' expression, immune cell infiltration, and inflammatory cytokine levels. The 30 OA patients were randomized and clustered into three groups using WGCNA analysis based on the hub genes, and diverse immune status was found in different clusters. Of interest, older patients were more likely to be classified into a cluster with higher levels of inflammatory cytokines IL-6 and less infiltration of immune cells. Based on the scRNA-sequencing data, we found that the hub genes had relatively higher expression in macrophages and B cells than other immune cells. Moreover, inflammation-related pathways were significantly enriched in macrophages.

CONCLUSION

These results suggest that AMP-related genes are closely involved in alterations of OA synovial inflammation. The transcriptional level of hub genes could serve as a potential diagnostic marker for OA.

β Boswellic Acid Blocks Articular Innate Immune Responses: An In Silico and In Vitro Approach to Traditional Medicine

Osteoarthritis (OA) is hallmarked as a silent progressive rheumatic disease of the whole joint. The accumulation of inflammatory and catabolic factors such as IL6, TNFα, and COX2 drives the OA pathophysiology into cartilage degradation, synovia inflammation, and bone destruction. There is no clinical available OA treatment. Although traditional ayurvedic medicine has been using Boswellia serrata extracts (BSE) as an antirheumatic treatment for a millennium, none of the BSE components have been clinically approved. Recently, β boswellic acid (BBA) has been shown to reduce in vivo OA-cartilage loss through an unknown mechanism. We used computational pharmacology, proteomics, transcriptomics, and metabolomics to present solid evidence of BBA therapeutic properties in mouse and primary human OA joint cells. Specifically, BBA binds to the innate immune receptor Toll-like Receptor 4 (TLR4) complex and inhibits both TLR4 and Interleukin 1 Receptor (IL1R) signaling in OA chondrocytes, osteoblasts, and synoviocytes. Moreover, BBA inhibition of TLR4/IL1R downregulated reactive oxygen species (ROS) synthesis and MAPK p38/NFκB, NLRP3, IFNαβ, TNF, and ECM-related pathways. Altogether, we present a solid bulk of evidence that BBA blocks OA innate immune responses and could be transferred into the clinic as an alimentary supplement or as a therapeutic tool after clinical trial evaluations.

Decreased Peli1 expression attenuates osteoarthritis by protecting chondrocytes and inhibiting M1-polarization of macrophages

AIMS

Pellino1 (Peli1) has been reported to regulate various inflammatory diseases. This study aims to explore the role of Peli1 in the occurrence and development of osteoarthritis (OA), so as to find new targets for the treatment of OA.

METHODS

After inhibiting Peli1 expression in chondrocytes with small interfering RNA (siRNA), interleukin (IL)-1β was used to simulate inflammation, and OA-related indicators such as synthesis, decomposition, inflammation, and apoptosis were detected. Toll-like receptor (TLR) and nuclear factor-kappa B (NF-κB) signalling pathway were detected. After inhibiting the expression of Peli1 in macrophages Raw 264.7 with siRNA and intervening with lipopolysaccharide (LPS), the polarization index of macrophages was detected, and the supernatant of macrophage medium was extracted as conditioned medium to act on chondrocytes and detect the apoptosis index. The OA model of mice was established by destabilized medial meniscus (DMM) surgery, and adenovirus was injected into the knee cavity to reduce the expression of Peli1. The degree of cartilage destruction and synovitis were evaluated by haematoxylin and eosin (H&E) staining, Safranin O/Fast Green staining, and immunohistochemistry.

RESULTS

In chondrocytes, knockdown of Peli1 produced anti-inflammatory and anti-apoptotic effects by targeting the TLR and NF-κB signalling pathways. We found that in macrophages, knockdown of Peli1 can inhibit M1-type polarization of macrophages. In addition, the corresponding conditioned culture medium of macrophages applied to chondrocytes can also produce an anti-apoptotic effect. During in vivo experiments, the results have also shown that knockdown Peli1 reduces cartilage destruction and synovial inflammation.

CONCLUSION

Knockdown of Peli1 has a therapeutic effect on OA, which therefore makes it a potential therapeutic target for OA.Cite this article: Bone Joint Res 2023;12(2):121-132.

Immunoregulation of synovial macrophages for the treatment of osteoarthritis

Osteoarthritis (OA) is the most common joint disease affecting approximately 10% of men and 18% of women older than 60. Its pathogenesis is still not fully understood; however, emerging evidence has suggested that chronic low-grade inflammation is associated with OA progression. The pathological features of OA are articular cartilage degeneration in the focal area, including new bone formation at the edge of the joint, subchondral bone changes, and synovitis. Conventional drug therapy aims to prevent further cartilage loss and joint dysfunction. However, the ideal treatment for the pathogenesis of OA remains to be defined. Macrophages are the most common immune cells in inflamed synovial tissues. In OA, synovial macrophages undergo proliferation and activation, thereby releasing pro-inflammatory cytokines, including interleukin-1 and tumor necrosis factor-α, among others. The review article discusses (1) the role of synovial macrophages in the pathogenesis of OA; (2) the progress of immunoregulation of synovial macrophages in the treatment of OA; (3) novel therapeutic targets for preventing the progress of OA or promoting cartilage repair and regeneration.

Single-cell protein activity analysis reveals a novel subpopulation of chondrocytes and the corresponding key master regulator proteins associated with anti-senescence and OA progression

Background

Osteoarthritis (OA) is a prevalent senescence-related disease with substantial joint pain, loss of joint function, and cartilage degeneration. Because of the paucity of single-cell studies of OA and the gene dropout problem of single-cell RNA sequencing, it is difficult to acquire an in-depth understanding of the molecular characteristics of various chondrocyte clusters.

Methods

Here, we aimed to provide new insights into chondrocyte senescence and a rationale for the development of effective intervention strategies for OA by using published single-cell RNA-sequencing data sets and the metaVIPER algorithm (Virtual Inference of Protein activity by Enriched Regulon). This algorithm was employed to present a proteome catalog of 62,449 chondrocytes from the cartilage of healthy individuals and OA patients at single-cell resolution. Furthermore, histopathologic analysis was carried out in cartilage samples from clinical patients and experimental mouse models of OA to validate above results.

Results

We identified 16 protein-activity-based chondrocyte clusters as well as the underlying master regulators in each cluster. By assessing the enrichment score of each cluster in bulk RNA-sequencing data, followed by gene-set variation analysis, we preliminarily identified a novel subpopulation of chondrocytes (cluster 3). This clinically relevant cluster was predicted to be the main chondrocyte cluster responsible for maintaining cellular homeostasis and anti-senescence. Specifically, we uncovered a set of the key leading-edge proteins of cluster 3 by validating the robustness of the above results using another human chondrocyte single-cell RNA-sequencing data set, consisting of 24,675 chondrocytes. Furthermore, cartilage samples from clinical patients and experimental mouse models of OA were used to evaluate the expression patterns of these leading-edge proteins, and the results indicated that NDRG2, TSPYL2, JMJD6 and HMGB2 are closely associated with OA pathogenesis and might play critical roles in modulating cellular homeostasis and anti-senescence in chondrocytes.

Conclusion

Our study revealed a novel subpopulation of chondrocytes that are critical for anti-progression of OA and the corresponding master regulator proteins, which might serve as therapeutic targets in OA.

Minimally invasive treatment of osteoarthritis of the hip joint by radiofrequency denervation: a clinical case

Background. At present, there is an increasing trend towards the spread of osteoarthritis among the population of Russia and the world, and therefore the search for an effective and low-traumatic method of stopping pain syndrome of directional exposure in coxarthrosis is an urgent and important problem of modern medicine. Clinical Case Description. A clinical case of treatment of a 64-year-old patient, a working pensioner, with complaints of severe pain in the left hip joint and a clinical picture of stage IV coxarthrosis according to the Kellgren and Lawrence classification, is presented at the Multidisciplinary medical Center of the Bank of Russia. Previously, the patient was given indications for planned joint arthroplasty due to the ineffectiveness of conservative treatment courses. The pain syndrome on the visual analogue scale (VAS) was 9 points, according to the Harris Hip Score 32 points (unsatisfactory result). In connection with the development of an acute concomitant disease, radiofrequency denervation (RFD) of the left hip joint was performed with discharge the next day and a positive outcome in the form of a decrease in pain for a long period. VAS: 1st day - 3 points, 1 month - 2 points, 6 months - 6 points, 12 months - 7 points, as well as according to the "Harris Hip Score": 1 month after the test 82 points (good result), after 6 months 76 points (satisfactory result) Conclusion. As this clinical case showed, RFD is an alternative for patients with osteoarthritis of the hip joint who are contraindicated in total arthroplasty, and conservative treatment does not give long-term positive results in severe pain.

Role of Mesenchymal Stem Cells and Their Paracrine Mediators in Macrophage Polarization: An Approach to Reduce Inflammation in Osteoarthritis

Osteoarthritis (OA) is a low-grade inflammatory disorder of the joints that causes deterioration of the cartilage, bone remodeling, formation of osteophytes, meniscal damage, and synovial inflammation (synovitis). The synovium is the primary site of inflammation in OA and is frequently characterized by hyperplasia of the synovial lining and infiltration of inflammatory cells, primarily macrophages. Macrophages play a crucial role in the early inflammatory response through the production of several inflammatory cytokines, chemokines, growth factors, and proteinases. These pro-inflammatory mediators are activators of numerous signaling pathways that trigger other cytokines to further recruit more macrophages to the joint, ultimately leading to pain and disease progression. Very few therapeutic alternatives are available for treating inflammation in OA due to the condition's low self-healing capacity and the lack of clear diagnostic biomarkers. In this review, we opted to explore the immunomodulatory properties of mesenchymal stem cells (MSCs) and their paracrine mediators-dependent as a therapeutic intervention for OA, with a primary focus on the practicality of polarizing macrophages as suppression of M1 macrophages and enhancement of M2 macrophages can significantly reduce OA symptoms.

Construction and analysis of a lncRNA–miRNA–mRNA competing endogenous RNA network from inflamed and normal synovial tissues after anterior cruciate ligament and/or meniscus injuries

Background: Despite ample evidence demonstrating that anterior cruciate ligament (ACL) and meniscus tears are associated with posttraumatic osteoarthritis (PTOA) development, the contributing factors remain unknown. Synovial inflammation has recently been recognized as a pivotal factor in the pathogenesis of OA. However, there is a lack of data on synovial profiles after ACL or meniscus injuries, which may contribute to PTOA.

Methods: Twelve patients with ACL tears and/or meniscus injuries were recruited. During surgery, synovial tissues were obtained from the injured knees. The inflammation status of the synovium was characterized according to macroscopic criteria and histological synovitis grades. Then the synovial tissues were classified as control group or inflamed group. High-throughput RNA sequencing of the synovial samples (3 vs. 3) was conducted to identify differentially expressed (DE) RNAs. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and protein–protein interaction (PPI) analyses were performed to investigate DE mRNAs. Next, competing endogenous RNA (ceRNA) networks were constructed based on bioinformatics analyses. Associations of the identified DE genes (DEGs) with infiltrating immune cells were explored using Pearson correlation analysis.

Results: The results showed that 2793 mRNAs, 3392 lncRNAs and 211 miRNAs were significantly DE between two groups. The top 3 significantly upregulated GO terms and KEGG pathways were immune response, adaptive immune response and immune system process, systemic lupus erythematosus, haematopoietic cell lineage and cytokine–cytokine receptor interaction, respectively. In PPI networks, the top 10 hub genes were IL6, CCR7, C3, CCR5, CXCR3, CXCL8, IL2, CCR3, CCR2 and CXCL1. Seven mRNAs (EPHA5, GSN, ORC1, TLN2, SOX6, NKD2 and ADAMTS19), 4 lncRNAs (MIR4435-2HG, TNXA, CEROX1 and TMEM92-AS1) and 3 miRNAs (miR-486-5p, miR-199a-3p and miR-21-3p) were validated by quantitative real-time polymerase chain reaction and sub-networks were constructed. In correlation analysis, MMP9 correlated positively with M0 macrophages and plasma cells, NKD2 positively with CD8 T cells, and CCR7 and IL2RB positively with naive B cells.

Conclusion: Our study provides foundational synovial inflammation profiles following knee trauma. The ceRNA and PPI networks provide new insight into the biological processes and underlying mechanisms of PTOA. The differential infiltration profiles of immune cells in synovium may contribute to PTOA development. This study also highlights immune-related DEGs as potential PTOA treatment biomarkers.

Bibliometric and visualization analysis of macrophages associated with osteoarthritis from 1991 to 2021

Background

Macrophages significantly contributes to symptomology and structural progression of osteoarthritis (OA) and raise increasing attention in the relative research field. Recent studies have shown that tremendous progress has been made in the research of macrophages associated with osteoarthritis. However, a comprehensive bibliometric analysis is lacking in this research field. This study aimed to introduce the research status as well as hotspots and explore the field of macrophages research in OA from a bibliometric perspective.

Methods

This study collected 1481 records of macrophages associated with osteoarthritis from 1991 to 2021 in the web of science core collection (WoSCC) database. CiteSpace, VOSviewer, and R package “bibliometrix” software were used to analyze regions, institutions, journals, authors, and keywords to predict the latest trends in macrophages associated with osteoarthritis research.

Results

The number of publications related to macrophages associated with osteoarthritis is increasing annually. China and the USA, contributing more than 44% of publications, were the main drivers for research in this field. League of European Research Universities was the most active institution and contributed the most publications. Arthritis and Rheumatism is the most popular journal in this field with the largest publications, while Osteoarthritis and Cartilage is the most co-cited journal. Koch AE was the most prolific writer, while Bondeson J was the most commonly co-cited author. “Rheumatology”, “Orthopedics”, and “Immunology” were the most widely well-represented research areas of OA associated macrophages. “Rheumatoid arthritis research”, “clinical symptoms”, “regeneration research”, “mechanism research”, “pathological features”, and “surgery research” are the primary keywords clusters in this field.

Conclusion

This is the first bibliometric study comprehensively mapped out the knowledge structure and development trends in the research field of macrophages associated with osteoarthritis in recent 30 years. The results comprehensively summarize and identify the research frontiers which will provide a reference for scholars studying macrophages associated with osteoarthritis.

Identification of cellular heterogeneity and immunogenicity of chondrocytes via single-cell RNA sequencing technique in human osteoarthritis

Background: Osteoarthritis (OA) has placed a heavy burden to the economy and humanistics. To explore the biological functions and markers of chondrocytes contributes significantly to the accurate diagnosis and targeted treatment of OA.

Methods: We systematically analyzed the immunogenicity and biological function of varied chondrocytes at single cell resolution, and identified the chondrocyte subtypes and biomarkers involved in the development of OA, which are verified in the bulk sequencing cohort.

Results: Based on previous study, we defined eight subtypes of chondrocytes with different biological functions, finding out that effector chondrocytes (ECs) and fibrocartilage chondrocytes (FCs) may promote the development of OA. Compared with other chondrocytes, ECs and FCs show stronger immunogenicity. FCs mainly affects the degeneration of cartilage caused by fibrous degeneration, while ECs mainly exerts immune function and causes tissues inflammation. In addition, the canonical gene markers of EC and FC assist with the prediction of OA, which has been verified in Bulk RNA sequencing data from two GEO datasets.

Conclusion: In summary, this study provides a new perspective for the exploration of cellular heterogeneity and pathophysiology in OA and will make contribution to the accurate diagnosis and targeted treatment of OA.

Phytochemical Evaluation and Anti-Inflammatory Potential of Miconia albicans (Sw.) Triana Extracts

The plant Miconia albicans (Sw.) Triana has been popularly used in Brazil to treat chronic inflammatory disturbances, such as osteoarthritis. This disease affects 250 million people worldwide, and is associated with intense pain and loss of articular function. There is a lack of information about the phytochemistry and bioactivity of M. albicans. Therefore, this study determined the chemical composition of some extracts and evaluated their cytotoxicity, along with their antioxidant and anti-inflammatory, activities using in vitro models. Aqueous and ethanolic extracts were prepared. Afterwards, a liquid–liquid partition was developed using chloroform, ethyl acetate, and n-butanol. The extracts were characterized by LC–MS, and their biological activities were evaluated on epithelial cells (Vero), tumoral hepatic cells (Hep-G2), and THP-1 macrophages. LC–MS analyses identified several flavonoids in all fractions, such as quercetin, myricetin, and their glycosides. The crude extracts and n-butanol fractions did not present cytotoxicity to the cells. The non-toxic fractions presented significant antioxidant activity when evaluated in terms of DPPH scavenging activity, lipid peroxidation, and ROS inhibition. THP-1 macrophages treated with the n-butanol fraction (250 µg/mL) released fewer pro-inflammatory cytokines, even in the presence of LPS. In the future, it will be necessary to identify the phytochemicals that are responsible for anti-inflammatory effects for the discovery of new drugs. In vivo studies on M. albicans extracts are still required to confirm their possible mechanisms of action.

Repurposing drugs to inhibit innate immune responses associated with TLR4, IL1, and NLRP3 signaling in joint cells

Osteoarthritis (OA) affects more than 300 million people worldwide and it is about to become the first disabling disease. OA is characterized by the progressive degradation of the articular cartilage but is a disease of the whole joint. Articular innate immune responses (IIR) associated with tissue degradation contribute to its progression. However, no treatment is available to block these IIRs. Through data text mining and computational pharmacology, we identified two clinical available drugs, naloxone, and thalidomide, with potential inhibitory properties on toll-like receptor 4 (TLR4), a major activator of these IIR. Proteome analysis confirmed that activation of this receptor or the IL1 receptor generated OA-like and gout-like proteomic changes in human primary chondrocytes. Both compounds were found to block TLR4 complex and inhibit TLR4 and IL1R-mediated IIR in OA chondrocytes, osteoblasts, and synoviocytes. Furthermore, naloxone and thalidomide inhibitory effects involved the downregulation of the NLRP3 inflammasome pathway, which is downstream of TLR4/IL1R signaling. We demonstrated that these compounds, within a therapeutic range of concentrations, exhibited anti-inflammatory and anti-catabolic properties in joint primary OA cells without any toxic effect. This data underpins naloxone & thalidomide repurpose to treat OA-associated inflammatory responses.

Aerobic exercise combined with glucosamine hydrochloride capsules inhibited the apoptosis of chondrocytes in rabbit knee osteoarthritis by affecting TRPV5 expression

OBJECTIVE

This study aimed to investigate the effect of aerobic exercise combined with glucosamine (OTL) on the apoptosis of chondrocytes of rabbit knee osteoarthritis (KOA) by affecting the expression of TRPV5.

METHODS

After the KOA white rabbit model was established, aerobic training and OTL treatment were performed, then the model joints were evaluated by Mankin, HE staining was used to observe the pathological changes of articular cartilage, TUNEL and immunohistochemistry were used to detect chondrocyte apoptosis. Knee chondrocytes were isolated and identified by Alcian Blue and type II collagen fiber staining. The cells were treated with iodoacetic acid (MIA) to simulate osteoarthritis in vitro, and then the effect of TRPV5 on apoptosis was detected by flow cytometry, in addition, apoptosis-related proteins and TRPV5 were detected by western blotting and qRT-PCR.

RESULTS

Both aerobic exercise and OTL treatment could significantly reduce the Mankin score of KOA model, and could effectively inhibit chondrocyte apoptosis in the KOA model, and inhibit the expression of caspase 3 and caspase 9 in the KOA model. TRPV5 expression was significantly increased in the model, while both aerobic exercise and OTL could reverse its expression. The low-expression of TRPV5 significantly reversed the role of MIA in promoting apoptosis and apoptosis-related proteins of knee chondrocytes, while overexpressing TRPV5 promoted MIA-induced apoptosis and apoptosis-related proteins.

CONCLUSION

Aerobic exercise combined with glucosamine hydrochloride capsules inhibited the apoptosis of chondrocytes in rabbit KOA by affecting the expression of TRPV5.

Elderly Runners and Osteoarthritis: A Systematic Review

PURPOSE

The impact of running on the onset of osteoarthritis (OA) is controversial. This study compared the incidence of OA in elderly runners versus nonrunners.

MATERIAL AND METHODS

This systematic review was conducted according to the PRISMA guidelines. PubMed, Google scholar, Embase, and Web of Science databases were accessed in January 2022. All the published clinical studies investigating OA onset in runners versus non-runners were considered. Studies reporting data on OA and participants in other sports were excluded. Only studies investigating patients with a mean age older than 55 years were considered. The methodological quality of the articles was evaluated using the Newcastle-Ottawa Scale (NOS).

RESULTS

Data from 3001 participants and 6674 joints were retrieved. The mean age was 59.4±2.7 years. The mean body mass index was 24.6±2.5 kg/m2. The 5 included articles (963 runners, 2038 nonrunners) did not report significant differences in runners compared with controls.

CONCLUSION

Middle aged runners did not present greater imaging or clinical signs of OA compared with nonrunner controls. Running at elite or recreational level did not increase the rate of OA progression in individuals older than 50 years.

Osteoarthritis in Athletes Versus Nonathletes: A Systematic Review

INTRODUCTION

Joint overload and sport-related injuries may accelerate the development of osteoarthritis (OA). A systematic review of the literature was performed to establish the risk of athletes to develop premature OA compared with nonathletes.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines. PubMed, Google scholar, Embase, and Web of Science databases were accessed in June 2021. All the published clinical studies investigating OA onset in athletes versus nonathletes were considered. Studies reporting data on secondary and/or post-traumatic OA were excluded.

RESULTS

Data from 32 articles (20,288 patients) were retrieved. The mean age was 67.8±10.0 years and the mean body mass index was 25.0±2.5 kg/m2. 74% (6859 patients) of the athletes suffered from premature OA. Of them, 21% were active in soccer, 11% in handball, 11% in ice-hockey, 3% in football, and 0.3% in rugby. 26% of the athletes reported no significant differences in OA progression compared with healthy controls. Of these athletes, 47% were runners, 5% dancers, and 1% triathletes.

CONCLUSION

Certain sports, such as soccer, handball, ice-hockey, and rugby are more likely to be associated with premature knee and hip OA. Conversely, runners and ballet dancers do not evidence significant increase in OA. Moderate and recreational exposure to aerobic sports does not accelerate the development of OA.

Factors Influencing Pain Response Following Patient Education and Supervised Exercise in Male and Female Subjects With Hip Osteoarthritis

OBJECTIVE

To understand factors associated with pain intensity responder status following nonsurgical hip osteoarthritis (OA) intervention, according to sex.

METHODS

Data were from individuals with hip OA participating in the Danish Good Life With Osteoarthritis in Denmark 8-week education and exercise program. The following factors were recorded at program entry: age; education; mental well-being; comorbidities; body mass index; symptoms in hip, knee, and low back; and program-specific factors including education sessions, former participant lectures, and supervised exercise sessions. Pain intensity was recorded at baseline and at month 3 (post-program) on a 0-100-mm visual analog scale. Response was defined as pain intensity improvement of ≥30% from baseline to post-program. Logistic regression was used and conducted separately in male and female subjects.

RESULTS

The sample included 791 men and 2,253 women. Female subjects had a mean baseline pain score of 47.2 of 100 (95% confidence interval [95% CI] 46.4-48.1) and male subjects had a score of 41.7 (95% CI 40.3-43.1). By post-program, the proportion of pain responders was 50.4% among women and 45.8% among men (difference P = 0.025). Among women, program-specific factors (attending former participant lectures and more supervised exercise sessions) were positively associated with pain response, as were better mental well-being and fewer comorbidities, while symptoms in other joints/sites were associated with a decreased likelihood of response. Among men, program-specific factors were not associated with response, while better mental well-being and fewer comorbidities were associated with being a responder.

CONCLUSION

Findings suggest that the influence of some factors on pain response differ for male and female subjects and point to a potential need for targeted approaches for men and women who may require different key messages/approaches from health care providers.

Long-term sick leave for back pain, exposure to physical workload and psychosocial factors at work, and risk of disability and early-age retirement among aged Swedish workers

Purpose

To assess the risk of disability and early-age retirement associated with previous long-term sickness absence for back pain (back-pain SA), exposure to high physical workload, low job control, high demands and high strain, and to evaluate effect modification by work factors on the relationship between back-pain SA and premature retirement.

Methods

All employed Swedish residents born 1946–1955 (n = 835,956) were followed up from 2010 to 2016 for disability (DP) and early-age pension (EAP). Associations of premature retirement with exposure to work factors and back-pain SA in the 3 years before follow-up were estimated through proportional hazards models. Retirement, back-pain SA and covariates were assessed through administrative sources, and exposure to work factors through a job-exposure matrix.

Results

In both genders, back-pain SA was associated with DP (> 1 episode: HR 3.23 among men; HR 3.12 among women) and EAP (> 1 episode: HR 1.24 among men; HR 1.18 among women). Higher physical workload and lower job control were also associated with an increased DP risk in both genders, whereas higher job demands showed a decreased risk. For EAP, associations with work factors were weak and inconsistent across genders. No effect modification by work factors was found, except for a negative effect modification by job strain on DP risk among women, i.e. a reduced effect of back-pain SA with increasing exposure.

Conclusion

Back-pain SA was a significant predictor of both DP and EAP, while work factors were consistently associated only with DP. Our results indicate that the joint effect of back-pain SA and work factors on DP is additive and does not support effect modification by work factors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00420-022-01862-8.

Tangeretin suppresses osteoarthritis progression via the Nrf2/NF-κB and MAPK/NF-κB signaling pathways

BACKGROUND

Osteoarthritis (OA) is a globally prevalent degenerative disease characterized by extracellular matrix (ECM) degradation and inflammation. Tangeretin is a natural flavonoid that has anti-inflammatory properties. Studies have not explored whether tangeretin modulates OA development.

PURPOSE

The aim of this study was to explore the potential effects and mechanism underlying the anti-OA properties of tangeretin.

STUDY DESIGN

Effects of tangeretin on OA were detected in chondrocytes and OA mouse model.

METHODS

Protective effects of tangeretin on murine articular chondrocytes treated with interleukin-1β (IL-1β) were evaluated using qPCR, western blot analysis, ELISA, ROS detection and immunofluorescent staining in vitro. Healing effect of tangeretin on cartilage degradation in mice was assessed through X-ray imaging, histopathological analysis, immunohistochemical staining and immunofluorescent staining in vivo.

RESULTS

Tangeretin suppressed IL-1β-mediated inflammatory mediator secretion and degradation of ECM in chondrocytes. The results showed that tangeretin abrogated destabilized medial meniscus (DMM)-induced cartilage degradation in mice. Mechanistic studies showed that tangeretin suppressed OA development by downregulating activation of NF-κB by activating Nrf2/HO-1 axis and suppressing MAPK signaling pathway.

CONCLUSION

Tangeretin abrogates OA progression by inhibiting inflammation as well as ECM degradation in chondrocytes and animal models. Effects of tangeretin are mediated through Nrf2/NF-κB and the MAPK/NF-κB pathways. Thus, tangeretin is a potential therapeutic agent for osteoarthritis treatment.

Piezoelectric Electrospun Fibrous Scaffolds for Bone, Articular Cartilage and Osteochondral Tissue Engineering

Osteochondral tissue (OCT) related diseases, particularly osteoarthritis, number among the most prevalent in the adult population worldwide. However, no satisfactory clinical treatments have been developed to date to resolve this unmet medical issue. Osteochondral tissue engineering (OCTE) strategies involving the fabrication of OCT-mimicking scaffold structures capable of replacing damaged tissue and promoting its regeneration are currently under development. While the piezoelectric properties of the OCT have been extensively reported in different studies, they keep being neglected in the design of novel OCT scaffolds, which focus primarily on the tissue's structural and mechanical properties. Given the promising potential of piezoelectric electrospun scaffolds capable of both recapitulating the piezoelectric nature of the tissue's fibrous ECM and of providing a platform for electrical and mechanical stimulation to promote the regeneration of damaged OCT, the present review aims to examine the current state of the art of these electroactive smart scaffolds in OCTE strategies. A summary of the piezoelectric properties of the different regions of the OCT and an overview of the main piezoelectric biomaterials applied in OCTE applications are presented. Some recent examples of piezoelectric electrospun scaffolds developed for potentially replacing damaged OCT as well as for the bone or articular cartilage segments of this interfacial tissue are summarized. Finally, the current challenges and future perspectives concerning the use of piezoelectric electrospun scaffolds in OCT regeneration are discussed.

Epidemiology of osteoarthritis

OBJECTIVE

To summarize the current state of the evidence regarding osteoarthritis (OA) prevalence, incidence and risk factors at the person-level and joint-level.

DESIGN

This was a narrative review that took a comprehensive approach regarding inclusion of potential risk factors. The review complements prior reviews of OA epidemiology, with a focus on new research and emerging topics since 2017, as well as seminal studies.

RESULTS

Studies continue to illustrate the high prevalence of OA worldwide, with a greater burden among older individuals, women, some racial and ethnic groups, and individuals with lower socioeconomic status. Modifiable risk factors for OA with the strongest evidence are obesity and joint injury. Topics of high interest or emerging evidence for a potential association with OA risk or progression include specific vitamins and diets, high blood pressure, genetic factors, metformin use, bone mineral density, abnormal joint shape and malalignment, and lower muscle strength/quality. Studies also continue to highlight the heterogenous nature of OA, with strong interest in understanding and defining OA phenotypes.

CONCLUSIONS

OA is an increasingly prevalent condition with worldwide impacts on many health outcomes. The strong evidence for obesity and joint injury as OA risk factors calls for heightened efforts to mitigate these risks at clinical and public health levels. There is also a need for continued research regarding how potential person- and joint-level risk factors may interact to influence the development and progression of OA.

Indoleamine 2, 3 Dioxygenase 1 Impairs Chondrogenic Differentiation of Mesenchymal Stem Cells in the Joint of Osteoarthritis Mice Model

Osteoarthritis (OA) is a serious joint inflammation that leads to cartilage degeneration and joint dysfunction. Mesenchymal stem cells (MSCs) are used as a cell-based therapy that showed promising results in promoting cartilage repair. However, recent studies and clinical trials explored unsatisfied outcomes because of slow chondrogenic differentiation and increased calcification without clear reasons. Here, we report that the overexpression of indoleamine 2,3 dioxygenase 1 (IDO1) in the synovial fluid of OA patients impairs chondrogenic differentiation of MSCs in the joint of the OA mice model. The effect of MSCs mixed with IDO1 inhibitor on the cartilage regeneration was tested compared to MSCs mixed with IDO1 in the OA animal model. Further, the mechanism exploring the effect of IDO1 on chondrogenic differentiation was investigated. Subsequently, miRNA transcriptome sequencing was performed for MSCs cocultured with IDO1, and then TargetScan was used to verify the target of miR-122-5p in the SF-MSCs. Interestingly, we found that MSCs mixed with IDO1 inhibitor showed a significant performance to promote cartilage regeneration in the OA animal model, while MSCs mixed with IDO1 failed to stimulate cartilage regeneration. Importantly, the overexpression of IDO1 showed significant inhibition to Sox9 and Collagen type II (COL2A1) through activating the expression of β-catenin, since inhibiting of IDO1 significantly promoted chondrogenic signaling of MSCs (Sox9, COL2A1, Aggrecan). Further, miRNA transcriptome sequencing of SF-MSCs that treated with IDO1 showed significant downregulation of miR-122-5p which perfectly targets Wnt1. The expression of Wnt1 was noticed high when IDO1 was overexpressed. In summary, our results suggest that IDO1 overexpression in the synovial fluid of OA patients impairs chondrogenic differentiation of MSCs and cartilage regeneration through downregulation of miR-122-5p that activates the Wnt1/β-catenin pathway.

3D-Printed Reinforcement Scaffolds with Targeted Biodegradation Properties for the Tissue Engineering of Articular Cartilage

Achieving regeneration of articular cartilage is challenging due to the low healing capacity of the tissue. Appropriate selection of cell source, hydrogel, and scaffold materials are critical to obtain good integration and long-term stability of implants in native tissues. Specifically, biomechanical stability and in vivo integration can be improved if the rate of degradation of the scaffold material matches the stiffening of the sample by extracellular matrix secretion of the encapsulated cells. To this end, a novel 3D-printed lactide copolymer is presented as a reinforcement scaffold for an enzymatically crosslinked hyaluronic acid hydrogel. In this system, the biodegradable properties of the reinforced scaffold are matched to the matrix deposition of articular chondrocytes embedded in the hydrogel. The lactide reinforcement provides stability to the soft hydrogel in the early stages, allowing the composite to be directly implanted in vivo with no need for a preculture period. Compared to pure cellular hydrogels, maturation and matrix secretion remain unaffected by the reinforced scaffold. Furthermore, excellent biocompatibility and production of glycosaminoglycans and collagens are observed at all timepoints. Finally, in vivo subcutaneous implantation in nude mice shows cartilage-like tissue maturation, indicating the possibility for the use of these composite materials in one-step surgical procedures.

Osteoarthritis complications and the recent therapeutic approaches

The accelerated prevalence of osteoarthritis (OA) disease worldwide and the lack of convenient management led to the frequent search for unprecedented and specific treatment approaches. OA patients usually suffer from many annoying complications that negatively influence their quality of life, especially in the elderly. Articular erosions may lead eventually to the loss of joint function as a whole which occurs over time according to the risk factors presented in each case and the grade of the disease. Conventional therapies are advancing, showing most appropriate results but still greatly associated with many adverse effects and have restricted curative actions as well. Hence, novel management tools are usually required. In this review, we summarized the recent approaches in OA treatment and the role of natural products, dietary supplements and nanogold application in OA treatment to provide new research tracks for more therapeutic opportunities to those who are in care in this field.

Therapeutic effects of bone marrow mesenchymal stem cells-derived exosomes on osteoarthritis

Mesenchymal stem cells (MSCs) have shown chondroprotective effects in clinical models of osteoarthritis (OA). However, effects of MSC‐derived exosomes on OA remain unclear. The study aimed to investigate the therapeutic potential of exosomes from human bone marrow MSCs (BM‐MSCs) in alleviating OA. The anterior cruciate ligament transection (ACLT) and destabilization of the medial meniscus (DMM) surgery were performed on the knee joints of a rat OA model, followed by intra‐articular injection of BM‐MSCs or their exosomes. In addition, BM‐MSC‐derived exosomes were administrated to primary human chondrocytes to observe the functional and molecular alterations. Both of BM‐MSCs and BM‐MSC‐derived exosomes alleviated cartilage destruction and subchondral bone remodelling in OA rat model. Administration of BM‐MSCs and exosomes could reduce joint damage and restore the trabecular bone volume fraction, trabecular number and connectivity density of OA rats. In addition, in vitro assays showed that BM‐MSCs‐exosomes could maintain the chondrocyte phenotype by increasing collagen type II synthesis and inhibiting IL‐1β–induced senescence and apoptosis. Furthermore, exosomal lncRNA MEG‐3 also reduced the senescence and apoptosis of chondrocytes induced by IL‐1β, indicating that lncRNA MEG‐3 might partially account the anti‐OA effects of BM‐MSC exosomes. The exosomes from BM‐MSCs exerted beneficial therapeutic effects on OA by reducing the senescence and apoptosis of chondrocytes, suggesting that MSC‐derived exosomes might provide a candidate therapy for OA treatment.

Efficacy and Mechanism of Electroacupuncture Treatment of Rabbits With Different Degrees of Knee Osteoarthritis: A Study Based on Synovial Innate Immune Response

Knee osteoarthritis (KOA) is a chronic degenerative bone and joint disease, which is often clinically manifested as pain, joint swelling, and deformity. Its pathological manifestations are mainly synovial inflammation and cartilage degeneration. This study aims to investigate the efficacy of electro-acupuncture (EA) on model rabbits with varying degrees of KOA and to study the mechanism of EA on KOA based on the innate immune response. Mild and moderate rabbit KOA models were established using a modified Hluth method, and EA was given to both the mild and moderate model groups. The Lequesne-MG index was used to evaluate the behavioral changes in the rabbits before and after EA treatment. Morphological changes in the synovial membrane and cartilage of each group were observed by H&E staining. The Mankin scoring standard and the Krenn scoring standard were used to score the pathology of the cartilage tissue and synovial tissue, respectively. The inflammatory factors and metalloproteinases were detected in the serum of each group by ELISA. The protein and messenger RNA (mRNA) expressions of important elements related to Toll-like receptors (TLRs)-mediated innate immune response in the synovial tissue were detected by Western blot and quantitative PCR (qPCR). The Lequesne-MG index score of the rabbits gradually increased with the modeling prolonged but decreased significantly after EA treatment, indicating that EA has a better effect on alleviating the pain and improving the dysfunction. The morphological analysis showed that the inflammation of and the damage to the synovial membrane and the cartilage tissue gradually deteriorated with the modeling prolonged. However, the synovial membrane inflammation was significantly relieved after EA treatment, and the cartilage injury showed signs of repair. The ELISA analysis showed that, with the modeling prolonged, the serum-related inflammatory factors and mechanism of metalloproteinases gradually increased but decreased after EA treatment. The tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and matrix metalloproteinase3 (MMP3) of EA1 group were significantly lower than those of EA2 group. Both Western blot and qPCR results showed that the protein and mRNA expressions of the elements related to the innate immune response in the synovial membrane increased gradually with the modeling prolonged, but decreased significantly after EA treatment. Additionally, the expression of some components in EA1 group was significantly lower than that in EA2 group. These results confirm that synovial inflammation gradually aggravated with time from the early to mid-stage of KOA. EA alleviated the inflammation and histological changes in KOA rabbits by inhibiting the TLRs-mediated innate synovial immune response. This suggests that using EA in the early stage of KOA may achieve a desirable efficacy.

Meta-Analyses of Multiple Gene Expression Profiles to Screen Hub Genes Related to Osteoarthritis

BACKGROUND

This study aimed to screen and validate the crucial genes involved in osteoarthritis (OA) and explore its potential molecular mechanisms.

METHODS

Four expression profile datasets related to OA were downloaded from the Gene Expression Omnibus (GEO). The differentially expressed genes (DEGs) from 4 microarray patterns were identified by the meta-analysis method. The weighted gene co-expression network analysis (WGCNA) method was used to investigate stable modules most related to OA. In addition, a protein-protein interaction (PPI) network was built to explore hub genes in OA. Moreover, OA-related genes and pathways were retrieved from Comparative Toxicogenomics Database (CTD).

RESULTS

A total of 1,136 DEGs were identified from 4 datasets. Based on these DEGs, WGCNA further explored 370 genes included in the 3 OA-related stable modules. A total of 10 hub genes were identified in the PPI network, including AKT1, CDC42, HLA-DQA2, TUBB, TWISTNB, GSK3B, FZD2, KLC1, GUSB, and RHOG. Besides, 5 pathways including "Lysosome," "Pathways in cancer," "Wnt signaling pathway," "ECM-receptor interaction" and "Focal adhesion" in CTD and enrichment analysis and 5 OA-related hub genes (including GSK3B, CDC42, AKT1, FZD2, and GUSB) were identified.

CONCLUSION

In this study, the meta-analysis was used to screen the central genes associated with OA in a variety of gene expression profiles. Three OA-related modules (green, turquoise, and yellow) containing 370 genes were identified through WGCNA. It was discovered through the gene-pathway network that GSK3B, CDC42, AKT1, FZD2, and GUSB may be key genes related to the progress of OA and may become promising therapeutic targets.

Reproducing the Biomechanical Environment of the Chondrocyte for Cartilage Tissue Engineering

It is well known that the biomechanical and tribological performance of articular cartilage is inextricably linked to its extracellular matrix (ECM) structure and zonal heterogeneity. Furthermore, it is understood that the presence of native ECM components, such as collagen II and aggrecan, promote healthy homeostasis in the resident chondrocytes. What is less frequently discussed is how chondrocyte metabolism is related to the extracellular mechanical environment, at both the macro and microscale. The chondrocyte is in immediate contact with the pericellular matrix of the chondron, which acts as a mechanocoupler, transmitting external applied loads from the ECM to the chondrocyte. Therefore, components of the pericellular matrix also play essential roles in chondrocyte mechanotransduction and metabolism. Recreating the biomechanical environment through tuning material properties of a scaffold and/or the use of external cyclic loading can induce biosynthetic responses in chondrocytes. Decellularized scaffolds, which retain the native tissue macro- and microstructure also represent an effective means of recapitulating such an environment. The use of such techniques in tissue engineering applications can ensure the regeneration of skeletally mature articular cartilage with appropriate biomechanical and tribological properties to restore joint function. Despite the pivotal role in graft maturation and performance, biomechanical and tribological properties of such interventions is often underrepresented. This review outlines the role of biomechanics in relation to native cartilage performance and chondrocyte metabolism, and how application of this theory can enhance the future development and successful translation of biomechanically relevant tissue engineering interventions. Impact statement Physiological cartilage function is a key criterion in the success of a cartilage tissue engineering solution. The in situ performance is dependent on the initial scaffold design as well as extracellular matrix deposition by endogenous or exogenous cells. Both biological and biomechanical stimuli serve as key regulators of cartilage homeostasis and maturation of the resulting tissue-engineered graft. An improved understanding of the influence of biomechanics on cellular function and consideration of the final biomechanical and tribological performance will help in the successful development and translation of tissue-engineered grafts to restore natural joint function postcartilage trauma or osteoarthritic degeneration, delaying the requirement for prosthetic intervention.

Involvement of Macrophages and Spinal Microglia in Osteoarthritis Pain

PURPOSE OF REVIEW

Chronic pain in osteoarthritis (OA) is characterized by pain sensitization, which involves both peripheral and central mechanisms. Studies suggest synovial macrophage and spinal microglia are implicated in pain sensitization in OA. We, therefore, reviewed the evidence of whether synovial macrophage and spinal microglia facilitated pain sensitization at diverse levels and how this event occurred in OA.

RECENT FINDINGS

Peripherally, joint inflammation is now believed to be a source of OA-related pain. Synovial macrophages accumulate in OA inflamed synovium and display a pro-inflammatory phenotype. Abundant macrophage-derived pro-inflammatory cytokines and other pain-causing substance facilitate hyperexcitation of primary sensory neuron in OA-related pain. Thus, activated synovial macrophage was considered a predictor for phenotyping of OA pain clinically. In response to affected joint-derived strong nociception, aberrant neuronal excitability is often associated with the hyperactivity of microglia in the spinal dorsal horn, thereby leading to central sensitization. Hyperactivity of synovial macrophage and spinal microglia underlies the mechanisms of pain sensitization at the peripheral and central level in OA. This concept provides not only a clinically relevant strategy for identifying the phenotype of OA-related pain but also has the potential to develop individualized interventions for OA, particularly in those patients with hyperactivity of macrophage and microglia.

β-blocker prescription is associated with lower cumulative risk of knee osteoarthritis and knee pain consultations in primary care: a propensity score matched cohort study

Objectives

To examine the association between β-blocker prescription and first primary-care consultation for knee OA, hip OA, knee pain and hip pain.

Methods

Data source: Clinical Practice Research Datalink. Participants aged ≥40 years in receipt of new oral β-blocker prescriptions were propensity score (PS) matched to an unexposed control. Cox proportional hazard ratios (HRs) and 95% CIs were calculated, and adjusted for non-osteoporotic fractures, number of primary-care consultations for knee or hip injury, and, the number of primary-care consultations, out-patient referrals and hospitalizations in the 12 months preceding cohort entry. Analysis was stratified according to β-blocker class and for commonly prescribed drugs. P < 0.05 was considered statistically significant.

Results

A total of 111 718 β-blocker–exposed participants were 1:1 PS matched to unexposed controls. β-blocker prescription was associated with reduced cumulative risk of knee OA, knee pain, and hip pain consultations [with a HR (95% CI) of 0.90 (0.83, 0.98), 0.88 (0.83, 0.92) and 0.85 (0.79, 0.90), respectively]. Propranolol and atenolol were associated with a lower incidence of knee OA and knee pain consultations with a HR of between 0.78 and 0.91. β-blockers were associated with reduced incidence of consultation for large-joint lower-limb OA/pain as a composite outcome, defined as the earliest of knee OA, knee pain, hip OA or a hip pain consultation [with a HR (95% CI) of 0.87 (0.84, 0.90)].

Conclusion

Commonly used β-blockers have analgesic properties for musculoskeletal pain. Atenolol might be a therapeutic option for OA and cardiovascular co-morbidities in which β-blockers are indicated, while propranolol may be suitable for people with co-morbid anxiety. A confirmatory randomized controlled trial is needed before clinical practice is changed.

Novel association between asthma and osteoarthritis: a nationwide health and nutrition examination survey

Background

Asthma and osteoarthritis (OA) are medical conditions that inhibit physical activity and adversely affect quality of life. Despite the high prevalence, there are limited studies focusing on the comorbid condition and association between asthma and OA. The aim of this study was to assess the prevalence of OA co-occurring with asthma and to identify the relevant clinical considerations.

Methods

Adult participants aged over 40 years who completed questionnaire assessments and spirometry tests were enrolled from the Korean National Health and Nutrition Examination Survey. Asthma and OA were defined based on the medical history of a diagnosis made by a doctor. Radiographic severities of OA were measured using the Kellgren–Lawrence grading system. Chronic obstructive pulmonary disease (COPD), as a comparative respiratory disease, was diagnosed based on the spirometric results.

Results

A total of 9344 subjects were enrolled, and the prevalence of asthma and COPD were 4.6% ± 0.3% and 12.0% ± 0.5%, respectively. The prevalence of OA in the asthma group was 31.9% ± 2.8%, which was significantly higher than that in the COPD (17.8% ± 1.5%) or control (16.2% ± 0.6%) groups. OA was more prevalent in patients with asthma after adjusting for age, sex, body mass index, and smoking status (OR 1.65; 95% CI 1.27–2.13). Furthermore, after adjustment of this model for the prescription of OA medication, OA remained independently associated with asthma (OR 1.56; 95% CI 1.10–2.20). Conversely, the relationship of OA medication with asthma was not significant (P = 0.64). This relationship was evident in patients with asthma without airflow limitation measured by spirometry (OR 1.97; 95% CI 1.32–2.93). Moreover, the radiographic severity of knee OA correlated with asthma (OR 1.10; 95% CI 1.0–‍‍1.21).

Conclusions

OA shows a high prevalence in patients with asthma, higher than in patients with COPD or the controls. The comorbid characteristics of these two conditions need to be considered in clinical practice.

The contribution of age and obesity to the number of painful joint sites in individuals reporting osteoarthritis: a population-based study

Objective

To investigate the association of OA risk factors with number of painful joint sites in a representative population sample.

Methods

Analysis of the 2009 Survey on Living with Chronic Diseases in Canada – Arthritis Component (n = 1614) for respondents reporting symptomatic OA. Variables: painful joints sites (hands, wrists, elbows, shoulders, hips, knees, ankles, feet, back, neck), joint symptom duration, sociodemographic characteristics, smoking, comorbidities and BMI. Zero-truncated negative binomial regressions were used to investigate the association between number of painful joint sites and the variables. Generalizability of findings was assessed by a similar analysis in a clinical hip/knee OA sample.

Results

The sample comprised 73% women and 56% were aged <65 years. The mean number of painful joint sites was 3.8: 84% reported pain at ≥2 sites, and 45% at ≥4 sites. Age, BMI, education and smoking were not associated with the number of joint sites. Significant associations were found with being female [rate ratio (RR) = 1.23, 95% CI 1.09, 1.39], having more comorbidities (RR = 1.11, 95% CI 1.07, 1.15) and longer symptom duration (RR = 1.16, 95% CI 1.09, 1.24), although the increase in joint sites with duration was small. Similar regression results were found with the clinical OA sample.

Conclusion

The lack of an association of age and BMI (obesity) with number of painful joint sites in OA raises questions about the role of these risk factors and our understanding of OA as a multi-joint disease. Filling this knowledge gap is critical to making progress with defining OA phenotypes and identifying potential aetiological mechanisms.

The impact of multijoint symptoms on patient-reported disability following surgery for lumbar spine osteoarthritis

BACKGROUND CONTEXT

In the lumbar spine osteoarthritis (LS-OA) population having surgery for lumbar spinal stenosis (LSS) symptoms, a significant proportion of patients experience limited benefit following the intervention. Thus, identifying contributing factors to this is important. Individuals with OA often have multiple joint symptoms, yet this has received limited attention in this population.

PURPOSE

Document the occurrence of joint symptoms among patients undergoing surgery for LS-OA, and investigate the influence of these symptoms on disability postsurgery.

DESIGN

Prospective study of consecutive patients followed to 12-month postsurgery.

PATIENT SAMPLE

Patients undergoing surgery (decompression surgery, with or without fusion) for neurogenic claudication with or without back pain due to LSS with a primary pathology diagnosis of LS-OA.

OUTCOMES MEASURES

Patient self-reported: Oswestry Disability Index (ODI), completed pre- and 12-month postsurgery; and, completed presurgery, age, sex, education, smoking, comorbid conditions, opioid use, short/long-term disability, depression and anxiety symptoms, back and leg pain intensity, presence of spondylolisthesis, procedure, prior spine surgery, and joints with arthritis and "pain/stiffness/swelling most days of the month" indicated on a homunculus (a joint site count was derived).

ASSESSMENTS

Height and weight, used to calculate body mass index; timed-up-and-go performance-based test.

METHODS

Outcome of interest was achieving a clinically important improvement (CII) in ODI by 12-month postsurgery (yes/no). The association between joint site count and achieving a CII was examined by multivariable logistic regression analyses, adjusted for other measures.

RESULTS

In all, 165 patients were included. The mean age was 67 years (range: 44-90) and 47% were female. Seventy-seven percent reported 1+ joint site other than the back, 62% reported 2+, and 25% reported 4+. Among those achieving a CII, 21% had 4+ joint sites, compared with 31% among those not achieving a CII. Adjusted analyses: Increasing joint site count was associated with increasing risk (odds ratio [OR]: 1.32, 95% confidence interval [CI]: 1.05, 1.66) of not achieving a CII; for those with 4+ joints, adjusted probability of not achieving a CII exceeded 50%. Also associated with an increased risk of not achieving a CII was presurgery anxiety (OR: 2.97, 95% CI: 1.02, 8.65), opioid use (OR: 2.89, 95% CI: 1.07, 7.82), and worse back pain intensity score (OR: 1.27, 95% CI: 1.05, 1.53).

CONCLUSIONS

Multijoint involvement was highly prevalent in this LS-OA surgical sample. Its association with poorer postsurgery outcome supports a comprehensive approach to OA management and care. Knowledge of multijoint symptoms should inform patient education, shared decision-making, and recommendations for postsurgical rehabilitation and self-management strategies.

Common risk factors and therapeutic targets in obstructive sleep apnea and osteoarthritis: An unexpectable link?

Osteoarthritis (OA) and Obstructive Sleep Apnea (OSA) are two highly prevalent chronic diseases for which effective therapies are urgently needed. Recent epidemiologic studies, although scarce, suggest that the concomitant occurrence of OA and OSA is associated with more severe manifestations of both diseases. Moreover, OA and OSA share risk factors, such as aging and metabolic disturbances, and co-morbidities, including cardiovascular and metabolic diseases, sleep deprivation and depression. Whether this coincidental occurrence is fortuitous or involves cause-effect relationships is unknown. This review aims at collating and integrating present knowledge on both diseases by providing a brief overview of their epidemiology and pathophysiology, analyzing current evidences relating OA and OSA and discussing potential common mechanisms by which they can aggravate each other. Such mechanisms constitute potential therapeutic targets whose pharmacological modulation may provide more efficient ways of reducing the consequences of OA and OSA and, thus, lessen the huge individual and social burden that they impose.

Global, regional prevalence, incidence and risk factors of knee osteoarthritis in population-based studies

BACKGROUND

Knee osteoarthritis (OA) is a major cause of disability in the elderly, however, there are few studies to estimate the global prevalence, incidence, and risk factors of knee OA.

METHODS

For this study, we searched PUBMED, EMBASE and SCOPUS from inception to April 4, 2020, without language restriction. We identified eligible studies with information on the prevalence or incidence of knee OA in population-based observational studies and extracted data from published reports. We did random-effects meta-analysis to generate estimates. This study was registered with PROSPERO (CRD42020181035).

FINDINGS

Out of 9570 records identified, 88 studies with 10,081,952 participants were eligible for this study. The pooled global prevalence of knee OA was 16⋅0% (95% CI, 14⋅3%-17⋅8%) in individuals aged 15 and over and was 22⋅9% (95% CI, 19⋅8%-26⋅1%) in individuals aged 40 and over. Correspondingly, there are around 654⋅1 (95% CI, 565⋅6-745⋅6) million individuals (40 years and older) with knee OA in 2020 worldwide. The pooled global incidence of knee OA was 203 per 10,000 person-years (95% CI, 106-331) in individuals aged 20 and over. Correspondingly, there are around annual 86⋅7 (95% CI, 45⋅3-141⋅3) million individuals (20 years and older) with incident knee OA in 2020 worldwide. The prevalence and incidence varied substantially between individual countries and increased with age. The ratios of prevalence and incidence in females and males were 1⋅69 (95% CI, 1⋅59-1⋅80, p<0⋅00) and 1⋅39 (95% CI, 1⋅24-1⋅56, p<0⋅00), respectively.

INTERPRETATION

Our study provides the global prevalence (16⋅0% [95% CI, 14⋅3%-17⋅8%]) and incidence (203 per 10,000 person-years [95% CI, 106-331]) of knee OA. These findings can be used to better assess the global health burden of knee OA. Further prospective cohort studies are warranted to identify modifiable risk factors for providing effectively preventive strategies in the early stages of the disease.

FUNDING

This work was supported by grants from the National Natural Science Foundation of China (nos. 81772384 and 81572174).

An Emerging Target in the Battle against Osteoarthritis: Macrophage Polarization

Osteoarthritis (OA) is one of the most prevalent chronic joint diseases worldwide, which causes a series of problems, such as joint pain, muscle atrophy, and joint deformities. Benefiting from some advances in the clinical treatment of OA, the quality of life of OA patients has been improved. However, the clinical need for more effective treatments for OA is still very urgent. Increasing findings show that macrophages are a critical breakthrough in OA therapy. Stimulated by different factors, macrophages are differentiated into two phenotypes: the pro-inflammatory M1 type and anti-inflammatory M2 type. In this study, various therapeutic reagents for macrophage-dependent OA treatment are summarized, including physical stimuli, chemical compounds, and biological molecules. Subsequently, the mechanisms of action of various approaches to modulating macrophages are discussed, and the signaling pathways underlying these treatments are interpreted. The NF-κB signaling pathway plays a vital role in the occurrence and development of macrophage-mediated OA, as NF-κB signaling pathway agonists promote the occurrence of OA, whereas NF-κB inhibitors ameliorate OA. Besides, several signaling pathways are also involved in the process of OA, including the JNK, Akt, MAPK, STAT6, Wnt/β-catenin, and mTOR pathways. In summary, macrophage polarization is a critical node in regulating the inflammatory response of OA. Reagents targeting the polarization of macrophages can effectively inhibit inflammation in the joints, which finally relieves OA symptoms. Our work lays the foundation for the development of macrophage-targeted therapeutic molecules and helps to elucidate the role of macrophages in OA.