Inflammatory biomarkers in osteoarthritis

Association of serum calcium, vitamin D, and C-reactive protein with all-cause and cause-specific mortality in an osteoarthritis population in the UK: a prospective cohort study

BACKGROUND

Osteoarthritis is a prevalent musculoskeletal condition, but the role of specific serum biomarkers, such as calcium, vitamin D, and C-reactive protein (CRP), in predicting mortality among individuals with osteoarthritis remains unclear.

METHODS

This observational study analyzed longitudinal data from over 500,000 participants in the UK Biobank, identifying those with osteoarthritis using ICD-9/10 codes or self-reported history. We performed multivariable cox-regression and flexible parametric survival model (FPSM) for survival analysis, with adjustments made through the inverse probability of treatment weight (IPTW) for baseline covariates identified by directed acyclic graphs (DAGs).

RESULTS

Of the 49,082 osteoarthritis population, the average age was 60.69 years, with 58.7% being female. During the follow-up period exceeding 15 years, a total of 5,522 people with osteoarthritis died. High serum calcium levels, compared to normal serum calcium levels, were significantly associated with all-cause mortality (hazard ratio (HR) 1.33, 95% confidence interval (CI) 1.11, 1.59), cardiovascular diseases (CVD)-related deaths (HR 1.55, 95% CI 1.05, 2.29), and other deaths (HR 1.59, 95% CI 1.20, 2.11). Low serum calcium levels, compared to normal serum calcium levels, was linked with CVD-related deaths (HR 2.06, 95% CI 1.02, 4.14). Vitamin D insufficiency, compared to sufficient vitamin D levels, was correlated with all-cause mortality (HR 1.22, 95% CI 1.13, 1.33), CVD-related deaths (HR 1.43, 95% CI 1.20, 1.72), and other deaths (HR 1.26, 95% CI 1.09, 1.45) but not with cancer-related deaths. High serum CRP levels, compared to normal CRP levels, were associated with all outcomes (all-cause mortality: HR 1.22, 95% CI 1.12, 1.33; CVD-related death: HR 1.24, 95%CI 1.03, 1.49; cancer-related death: HR 1.23, 95% CI 1.09, 1.40; other deaths: HR 1.19, 95%CI 1.03, 1.38).

CONCLUSIONS

Both high and low serum calcium levels, elevated CRP, and vitamin D insufficiency are potential predictors of increased mortality risk in the osteoarthritis population. These findings emphasize the importance of monitoring and possibly addressing these serum biomarkers in osteoarthritis populations to improve long-term outcomes. Further studies are needed to understand the underlying mechanisms and to propose therapeutic interventions.

Comparative Efficacy of Various Exercise Therapies and Combined Treatments on Inflammatory Biomarkers and Morphological Measures of Skeletal Muscle among Older Adults with Knee Osteoarthritis: A Network Meta-Analysis

Osteoarthritis is associated with high risks of sarcopenia in older populations. Exercise interventions are promising treatments for musculoskeletal impairments in knee osteoarthritis (KOA). The purpose of this study was to identify the comparative effects of exercise monotherapy and its adjunct treatments on muscle volume and serum inflammation for older individuals with KOA. A literature search in the electronic databases was comprehensively performed from this study's inception until April 2024 to identify relevant randomized controlled trials (RCTs) that reported muscle morphology and inflammation outcomes after exercise. The included RCTs were analyzed through a frequentist network meta-analysis (NMA). The standard mean difference (SMD) with a 95% confidence interval was estimated for treatment effects on muscle morphology and inflammation biomarkers. The relative effects on each main outcome among all treatment arms were compared using surface under the cumulative ranking (SUCRA) scores. The certainty of evidence (CoE) was assessed by the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) ranking system. Probable moderators of the treatment efficacy were investigated by network meta-regression analysis. This study included 52 RCTs (4255 patients) for NMA. Among the 27 identified treatment arms, isokinetic training plus physical modality as well as low-load resistance training plus blood-flow restriction yielded the most optimal treatment for inflammation reduction (-1.89; SUCRA = 0.97; CoE = high) and muscle hypertrophy (SMD = 1.28; SUCRA = 0.94; CoE = high). The patient's age (β = -0.73), the intervention time (β = -0.45), and the follow-up duration (β = -0.47) were identified as significant determinants of treatment efficacy on muscle hypertrophy. Exercise therapy in combination with noninvasive agents exert additional effects on inflammation reduction and muscle hypertrophy compared to its corresponding monotherapies for the KOA population. However, such treatment efficacy is likely moderated by the patient's age, the intervention time, and the follow-up duration.

Unraveling the molecular landscape of osteoarthritis: A comprehensive review focused on the role of non-coding RNAs

Osteoarthritis (OA) poses a significant global health challenge, with its prevalence anticipated to increase in the coming years. This review delves into the emerging molecular biomarkers in OA pathology, focusing on the roles of various molecules such as metabolites, noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Advances in omics technologies have transformed biomarker identification, enabling comprehensive analyses of the complex pathways involved in OA pathogenesis. Notably, ncRNAs, especially miRNAs and lncRNAs, exhibit dysregulated expression patterns in OA, presenting promising opportunities for diagnosis and therapy. Additionally, the intricate interplay between epigenetic modifications and OA progression highlights the regulatory role of epigenetics in gene expression dynamics. Genome-wide association studies have pinpointed key genes undergoing epigenetic changes, providing insights into the inflammatory processes and chondrocyte hypertrophy typical of OA. Understanding the molecular landscape of OA, including biomarkers and epigenetic mechanisms, holds significant potential for developing innovative diagnostic tools and therapeutic strategies for OA management.

Systemic inflammatory biomarkers are novel predictors of all-cause and cardiovascular mortality in individuals with osteoarthritis: a prospective cohort study using data from the NHANES

BACKGROUND

Chronic inflammation may contribute to increased mortality risk in individuals with osteoarthritis (OA), but research on the prognostic value of inflammatory biomarkers is limited. We aimed to evaluate the associations of the systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) with all-cause and cardiovascular mortality among US adults with OA.

METHODS

This cohort study included 3545 adults with OA aged ≥ 20 years from the National Health and Nutrition Examination Survey 1999-2020. The SII and SIRI were calculated using complete blood cell count data. Participants were categorized as having a higher or lower SII and SIRI using cutoff points derived by the maximally selected rank statistics method. Cox proportional hazards models, Fine-Gray competing risk regression models and time-dependent receiver operating characteristic (ROC) analysis were used to evaluate the associations between the SII/SIRI and mortality in OA patients.

RESULTS

Over a median follow-up of 5.08 (3.42-9.92) years, 636 (17.94%) deaths occurred, including 149 (4.20%) cardiovascular deaths. According to multivariable-adjusted models involving demographic, socioeconomic, and health factors, OA patients with a higher SII had a twofold greater risk of all-cause mortality than patients with a lower SII (HR 2.01; 95% CI: 1.50-2.68). Similarly, a higher SIRI was associated with an 86% increased risk of all-cause mortality relative to a lower SIRI (HR 1.86; 95% CI: 1.46-2.38). Similar to the trend found with all-cause mortality, patients with an elevated SII and SIRI had a 88% and 67% increased risk of cardiovascular mortality, respectively, compared to patients with a lower SII (HR 1.88; 95% CI: 1.16-3.03) and SIRI (HR 1.67; 95% CI: 1.14-2.44). Time-dependent ROC curves showed that both the SII and SIRI have moderate and valid performance in predicting short- and long-term mortality in patients with OA.

CONCLUSIONS

Higher SII and SIRI values were associated with greater all-cause and cardiovascular mortality among US adults with OA.

A personalized osteoarthritic joint-on-a-chip as a screening platform for biological treatments

Osteoarthritis (OA) is a highly disabling pathology, characterized by synovial inflammation and cartilage degeneration. Orthobiologics have shown promising results in OA treatment thanks to their ability to influence articular cells and modulate the inflammatory OA environment. Considering their complex mechanism of action, the development of reliable and relevant joint models appears as crucial to select the best orthobiologics for each patient. The aim of this study was to establish a microfluidic OA model to test therapies in a personalized human setting. The joint-on-a-chip model included cartilage and synovial compartments, containing hydrogel-embedded chondrocytes and synovial fibroblasts, separated by a channel for synovial fluid. For the cartilage compartment, a Hyaluronic Acid-based matrix was selected to preserve chondrocyte phenotype. Adding OA synovial fluid induced the production of inflammatory cytokines and degradative enzymes, generating an OA microenvironment. Personalized models were generated using patient-matched cells and synovial fluid to test the efficacy of mesenchymal stem cells on OA signatures. The patient-specific models allowed monitoring changes induced by cell injection, highlighting different individual responses to the treatment. Altogether, these results support the use of this joint-on-a-chip model as a prognostic tool to screen the patient-specific efficacy of orthobiologics.

Independent and combined effects of obesity and traumatic joint injury to the structure and composition of rat knee cartilage

Osteoarthritis (OA) is a multifactorial joint disease characterized by articular cartilage degradation. Risk factors for OA include joint trauma, obesity, and inflammation, each of which can affect joint health independently, but their interaction and the associated consequences of such interaction were largely unexplored. Here, we studied compositional and structural alterations in knee joint cartilages of Sprague-Dawley rats exposed to two OA risk factors: joint injury and diet-induced obesity. Joint injury was imposed by surgical transection of anterior cruciate ligaments (ACLx), and obesity was induced by a high fat/high sucrose diet. Depth-dependent proteoglycan (PG) content and collagen structural network of cartilage were measured from histological sections collected previously in Collins et al.. (2015). We found that ACLx primarily affected the superficial cartilages. Compositionally, ACLx led to reduced PG content in lean animals, but increased PG content in obese rats. Structurally, ACLx caused disorganization of collagenous network in both lean and obese animals through increased collagen orientation in the superficial tissues and a change in the degree of fibrous alignment. However, the cartilage degradation attributed to joint injury and obesity was not necessarily additive when the two risk factors were present simultaneously, particularly for PG content and collagen orientation in the superficial tissues. Interestingly, sham surgeries caused a through-thickness disorganization of collagen network in lean and obese animals. We conclude that the interactions of multiple OA risk factors are complex and their combined effects cannot be understood by superposition principle. Further research is required to elucidate the interactive mechanism between OA subtypes.

Exercise therapy for knee osteoarthritis pain: how does it work? A study protocol for a randomised controlled trial

INTRODUCTION

Muscle strengthening training (MST) and behavioural graded activity (BGA) show comparable effects on knee osteoarthritic (KOA) pain, but the mechanisms of action remain unclear. Both exercise-induced anti-inflammation and central sensitisation are promising pathways for pain relief in response to exercise therapy in patients with KOA: MST has the potential to decrease inflammation and BGA has the potential to decrease central sensitisation. Hence, this study aims to examine inflammation and central sensitisation as mediators for the effect of MST and/or BGA on pain in patients with KOA.

METHODS AND ANALYSIS

The Knee OsteoArthritis PAIN trial started on 10 January 2020 (anticipated end: April 2024). The three-arm clinical trial aims to recruit 90 KOA patients who will be randomly allocated to 12 weeks of (1) MST, (2) BGA or (3) care as usual. Assessments will be performed at baseline, 13 and 52 weeks after finishing the intervention. Outcomes, including pain (Knee injury and Osteoarthritis Outcome Score), were chosen in line with the OARSI recommendations for clinical trials of rehabilitation interventions for OA and the IMMPACT/OMERACT recommendations for the assessment of physical function in chronic pain clinical trials. Inflammation as well as features of central sensitisation (including conditioned pain modulation, offset analgesia, temporal summation of pain and event-related potentials following electrical stimulation), will be considered as treatment mediators. A multiple mediators model will be estimated with a path-analysis using structural equation models. In July 2023, all 90 KOA patients have been included and 42 participants already finished the study.

ETHICS AND DISSEMINATION

This study obtained ethics approval (B.U.N. 143201941843). Unravelling the mechanisms of action of exercise therapy in KOA will not only be extremely valuable for researchers, but also for exercise immunology and pain scientists and clinicians.

TRIAL REGISTRATION NUMBER

NCT04362618.

Circulating serotonin and dopamine concentrations in osteoarthritis patients: a pilot study on the effect of pelotherapy

Balneotherapy has demonstrated clinical efficacy in the management of pathologies involving low-grade inflammation and stress. In rheumatic conditions such as osteoarthritis (OA), this therapy presents anti-inflammatory properties and potential to improve psychological well-being. Although the neurohormones serotonin and dopamine are known to be involved in these processes, surprisingly they have not been studied in this context. The objective was to evaluate the effect of a cycle of balneotherapy with peloids (pelotherapy) on circulating serotonin and dopamine concentrations in a group of aged individuals with OA, after comparing their basal state to that of an age-matched control group. In our pilot study, a pelotherapy program (10 days) was carried out in a group of 16 elderly patients with OA, evaluating its effects on circulating serotonin and dopamine concentrations (measured by ELISA). Individuals with OA showed higher levels of serotonin and lower dopamine levels, in line with the inflammatory roles of these mediators. After pelotherapy, serotonin concentrations significantly decreased, potentially contributing to the previously reported anti-inflammatory effects of balneotherapy.

Exploring relationships among multi-disciplinary assessments for knee joint health in service members with traumatic unilateral lower limb loss: a two-year longitudinal investigation

Motivated by the complex and multifactorial etiologies of osteoarthritis, here we use a comprehensive approach evaluating knee joint health after unilateral lower limb loss. Thirty-eight male Service members with traumatic, unilateral lower limb loss (mean age = 38 yr) participated in a prospective, two-year longitudinal study comprehensively evaluating contralateral knee joint health (i.e., clinical imaging, gait biomechanics, physiological biomarkers, and patient-reported outcomes); seventeen subsequently returned for a two-year follow-up visit. For this subset with baseline and follow-up data, outcomes were compared between timepoints, and associations evaluated between values at baseline with two-year changes in tri-compartmental joint space. Upon follow-up, knee joint health worsened, particularly among seven Service members who presented at baseline with no joint degeneration (KL = 0) but returned with evidence of degeneration (KL ≥ 1). Joint space narrowing was associated with greater patellar tilt (r[12] = 0.71, p = 0.01), external knee adduction moment (r[13] = 0.64, p = 0.02), knee adduction moment impulse (r[13] = 0.61, p = 0.03), and CTX-1 concentration (r[11] = 0.83, p = 0.001), as well as lesser KOOSSport and VR-36General Health (r[16] = - 0.69, p = 0.01 and r[16] = - 0.69, p = 0.01, respectively). This longitudinal, multi-disciplinary investigation highlights the importance of a comprehensive approach to evaluate the fast-progressing onset of knee osteoarthritis, particularly among relatively young Service members with lower limb loss.

Impact of the Body Composition on Knee Osteoarthritis Assessed Using Bioimpedance Analysis

Osteoarthritis (OA) ranks among the most prevalent inflammatory diseases affecting the musculoskeletal system and is a leading cause of disability globally, impacting approximately 250 million individuals. This study aimed to assess the relationship between the severity of knee osteoarthritis (KOA) and body composition in postmenopausal women using bioimpedance analysis (BIA). The study included 58 postmenopausal females who were candidates for total knee arthroplasty. The control group consisted of 25 postmenopausal individuals with no degenerative knee joint changes. The anthropometric analysis encompassed the body mass index (BMI), mid-arm and mid-thigh circumferences (MAC and MTC), and triceps skinfold thickness (TSF). Functional performance was evaluated using the 30 s sit-to-stand test. During the BIA test, electrical parameters such as membrane potential, electrical resistance, capacitive reactance, impedance, and phase angle were measured. Additionally, body composition parameters, including Total Body Water (TBW), Extracellular Water (ECW), Intracellular Water (ICW), Body Cellular Mass (BCM), Extracellular Mass (ECM), Fat-Free Mass (FFM), and Fat Mass (FM), were examined. The study did not find any statistically significant differences in the electrical parameters between the control (0-1 grade on the K-L scale) and study groups (3-4 grade on the K-L scale). However, statistically significant differences were observed in BMI, fat mass (FM), arm circumference, triceps skinfold thickness, and sit-to-stand test results between the analyzed groups. In conclusion, the association between overweight and obesity with KOA in postmenopausal women appears to be primarily related to the level of adipose tissue and its metabolic activity.

Dietary total antioxidant capacity is associated with lower disease severity and inflammatory and oxidative stress biomarkers in patients with knee osteoarthritis

BACKGROUND

This study was designed to evaluate the association between dietary total antioxidant capacity and clinical and biochemical variables in patients with osteoarthritis.

METHODS

This cross-sectional study was conducted among 160 patients with mild-to-moderate knee osteoarthritis. The Likert version of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC Index) was used to assess the severity of clinical symptoms in patients with knee osteoarthritis. The secondary outcomes included inflammatory and oxidative stress biomarkers. The participants' usual diets were assessed using a food frequency questionnaire (FFQ), and the dietary total antioxidant capacity (TAC) was calculated based on the ferric reducing antioxidant power method. Additionally, clinical and biochemical variables were evaluated using standard methods.

RESULTS

The mean age of the participants was 57.2 ± 8.1 years, and 55.6% of them were females. The dietary TAC scores in this study ranged from 3.67 to 24.72, with a mean of 12.05 ± 5.3. We found a significant inverse trend between the dietary TAC score and the total Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score (P = 0.001), as well as the WOMAC stiffness (P = 0.008) and WOMAC physical function scores (P = 0.001). Furthermore, dietary TAC was inversely associated with serum concentrations of interleukin-6 (IL-6) (β = - 0.18, P = 0.020), tumor necrosis factor-α (TNF-α) (β = - 0.67, P < 0.001), matrix metalloproteinase-1 (MMP-1) (β = - 0.33, P < 0.001), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) (β = - 0.22, P = 0.005) levels.

CONCLUSION

The results of this study demonstrate an inverse association between dietary total antioxidant capacity and clinical and biochemical variables in patients with osteoarthritis.

Emerging molecular biomarkers in osteoarthritis pathology

Osteoarthritis (OA) is the most common form of arthritis resulting in joint discomfort and disability, culminating in decline in life quality. Attention has been drawn in recent years to disease-associated molecular biomarkers found in readily accessible biofluids due to low invasiveness of acquisition and their potential to detect early pathological molecular changes not observed with traditional imaging methodology. These biochemical markers of OA have been found in synovial fluid, blood, and urine. They include emerging molecular classes, such as metabolites and noncoding RNAs, as well as classical biomarkers, like inflammatory mediators and by-products of degradative processes involving articular cartilage. Although blood-based biomarkers tend to be most studied, the use of synovial fluid, a more isolated biofluid in the synovial joint, and urine as an excreted fluid containing OA biomarkers can offer valuable information on local and overall disease activity, respectively. Furthermore, larger clinical studies are required to determine relationships between biomarkers in different biofluids, and their impacts on patient measures of OA. This narrative review provides a concise overview of recent studies of OA using these four classes of biomarkers as potential biomarker for measuring disease incidence, staging, prognosis, and therapeutic intervention efficacy.

Antiangiogenic Effect of Dopamine and Dopaminergic Agonists as an Adjuvant Therapeutic Option in the Treatment of Cancer, Endometriosis, and Osteoarthritis

Dopamine (DA) and dopamine agonists (DA-Ag) have shown antiangiogenic potential through the vascular endothelial growth factor (VEGF) pathway. They inhibit VEGF and VEGF receptor 2 (VEGFR 2) functions through the dopamine receptor D2 (D2R), preventing important angiogenesis-related processes such as proliferation, migration, and vascular permeability. However, few studies have demonstrated the antiangiogenic mechanism and efficacy of DA and DA-Ag in diseases such as cancer, endometriosis, and osteoarthritis (OA). Therefore, the objective of this review was to describe the mechanisms of the antiangiogenic action of the DA-D2R/VEGF-VEGFR 2 system and to compile related findings from experimental studies and clinical trials on cancer, endometriosis, and OA. Advanced searches were performed in PubMed, Web of Science, SciFinder, ProQuest, EBSCO, Scopus, Science Direct, Google Scholar, PubChem, NCBI Bookshelf, DrugBank, livertox, and Clinical Trials. Articles explaining the antiangiogenic effect of DA and DA-Ag in research articles, meta-analyses, books, reviews, databases, and clinical trials were considered. DA and DA-Ag have an antiangiogenic effect that could reinforce the treatment of diseases that do not yet have a fully curative treatment, such as cancer, endometriosis, and OA. In addition, DA and DA-Ag could present advantages over other angiogenic inhibitors, such as monoclonal antibodies.

Curcuma as an anti-inflammatory component in treating osteoarthritis

Osteoarthritis (OA) is nowadays the most common musculoskeletal progressive condition. In recent decades, incidence and prevalence of OA have increased significantly. It is estimated that the prevalence of OA among adults older than 60 is 12%, affecting about 240 million people globally. The cause has not been fully elucidated, and therefore, there is no cure at the moment. It is a multifactorial degenerative disease with an inflammatory component mediated by numerous proinflammatory and anti-inflammatory cytokines, chemokines, and growth factors. OA is not yet fully understood; therefore, therapeutic interventions are aimed primarily at reducing symptoms and slowing the progression of joint destruction. Of the therapeutic options available, the most often prescribed are nonsteroidal antirheumatic drugs, which have numerous side effects. Therefore, a need for a safe, effective substance is differentiated, which will be used in adjuvant treatment, but also in disease prevention, and which will comparatively have no or fewer side effects. One such substance is curcumin, a hydrophobic polyphenol that forms the active component of the rhizome of the Curcuma longa plant. Several studies have shown its potent antioxidant and anti-inflammatory effect, non-toxicity, and safety at high daily doses. In addition to blocking chondrocyte apoptosis, curcumin also blocks the expression of cyclooxygenase, prostaglandin E-2 and proinflammatory cytokines in chondrocytes, potentially alleviating symptomatic diseases. Although there are significant variations in quality, methodology, and research results conducted on curcumin efficiency in OA treatment, curcumin is primarily recommended as systematic short-term and medium-term adjuvant therapy that reduces inflammatory biochemical factors. Reducing inflammation leads to better pain regulation and improved joint function, significantly reducing standard prescribed doses of drugs. The most researched daily doses of curcumin intake are 1000-2000 mg/day, which would also be the doses that most of the authors recommend. Further research is needed to determine the preventive role of curcumin in the pathogenesis of OA, the effects of long-term usage of curcumin in preventive purposes and treatment of osteoarthritis, as well as to determine optimal therapeutic dosages.

N6-methyladenine regulator-mediated RNA methylation modification patterns in immune microenvironment regulation of osteoarthritis

Background: Osteoarthritis is a common chronic degenerative disease, and recently, an increasing number of studies have shown that immunity plays an important role in the progression of osteoarthritis, which is exacerbated by local inflammation. The role of N6-methyladenine (m⁶A) modification in immunity is being explored. However, the role of m⁶A modification in regulating the immune microenvironment of osteoarthritis remains unknown. In this study, we sought to discuss the association between the N6-methyladenine (m⁶A) modification and the immune microenvironment of osteoarthritis. Methods: First, the data and gene expression profiles of 139 samples, including 33 healthy samples and 106 osteoarthritis samples, were obtained from the Genetics osteoARthritis and Progression (GARP) study. Then the differences in m⁶A regulators between healthy individuals and osteoarthritis patients were analyzed. The correlation between m⁶A regulators and immune characteristics was also investigated by single-sample gene set enrichment analysis (ssGSEA). Principal component analysis (PCA), Gene Set Variation Analysis (GSVA) enrichment analysis, weighted gene coexpression network analysis (WGCNA), and Associated R packages were used to identify the m⁶A phenotype and its biological functions. Results: A total of 23 m⁶A regulators were involved in this study. We found a close correlation between most m⁶A regulators in all samples as well as in osteoarthritis samples. VIRMA and LRPPRC were the most highly correlated m⁶A regulators and showed a positive correlation, whereas VIRMA and RBM15B were the most negatively correlated. M⁶A regulators are associated with osteoarthritis immune characteristics. For example, MDSC cell abundance was strongly correlated with RBM15B and HNRNPC. Meanwhile, RBM15B and HNRNPC were important effectors of natural killer cell immune responses. IGFBP3 is an important regulator of cytolytic activity immune function. We performed an unsupervised consensus cluster analysis of the osteoarthritis samples based on the expression of 23 m⁶A regulators. Three different m⁶A subtypes of osteoarthritis were identified, including 27 samples in subtype C1, 21 samples in subtype C2, and 58 samples in subtype C3. Different m⁶A subtypes have unique biological pathways and play different roles in the immune microenvironment of osteoarthritis. Conclusion: The m⁶A modification plays a crucial role in the diversity and complexity of the immune microenvironment in osteoarthritis.

The Effect of a Virtual Reality-Mediated Gamified Rehabilitation Program on Pain, Disability, Function, and Balance in Knee Osteoarthritis: A Prospective Randomized Controlled Study

Background: This prospective randomized controlled study is the first study that evaluates the disease-specific gamification through virtual reality (VR) glasses on pain, disability, functionality, and balance in knee osteoarthritis (OA). Materials and Methods: The demographic data of the patients were recorded. A total of 73 patients were divided into two groups (35 in experimental group and 38 in control group). All patients were evaluated with pain (visual analog scale [VAS]), functionality (Lysholm functional knee score [LFKS], 6 minutes walking test [6MWT]), disability (Western Ontario and McMaster Universities Arthritis Index [WOMAC]), and balance (Berg Balance Scale [BBS]) before treatment, after treatment (3th weeks), and 4 weeks after treatment (7th weeks). In the experimental group, plus the conservative treatment, a total of 15 sessions of a disease-specific gamification through VR glasses were applied. Results: VAS and WOMAC scores of the experimental group were lower at the 3th and 7th weeks than those of the control group (P = 0.005, P = 0.000), (P = 0.000). LFKS of the experimental group was higher at the 3th and 7th weeks than that of the control group (P = 0.005, P = 0.013). No difference was found between the groups in terms of 6MWTs (P > 0.05). BBS score of the experimental group was higher in the 7th week than that of the control group (P = 0.021). Conclusion: In knee OA, the disease-specific gamification through VR glasses added to the conservative treatment has a positive effect on pain, functionality, and balance. Side effects such as mild nausea, headache that did not last long, require additional treatment. In light of this, disease-specific gamification through VR glasses is effective and safe in knee OA, more studies that reveal the long-term effect on structural healing must be planned.

Effect of Curcuma longa extract on serum inflammatory markers and MRI-based synovitis in knee osteoarthritis: secondary analyses from the CurKOA randomised trial

BACKGROUND

Curcuma longa (CL) extract is modestly effective for relieving knee symptoms in knee osteoarthritis (OA) patients; however, its mechanism of action is unclear.

PURPOSE

We aimed to determine the effects of CL treatment on serum inflammatory markers over 12 weeks and to explore its potential effects on synovitis assessed by contrast-enhanced magnetic resonance imaging (CE-MRI) of the knee.

METHODS

Secondary analyses were conducted on the CL for knee OA (CurKOA) trial, which compared CL (n = 36) and placebo (n = 34) over 12 weeks for the treatment of knee OA. Systemic inflammatory markers (TNFα, IL6, and hsCRP) and a cartilage extracellular matrix degradative enzyme (MMP-3) were measured. A subgroup of participants (CL, n = 7; placebo, n = 5) underwent CE-MRI at baseline and a 12-week follow-up.

RESULTS

Over 12 weeks, there were no between-group differences in change in hsCRP, IL-6, and TNFα levels. MMP-3 levels decreased in both CL (-1.31 ng/ml [95%CI: -1.89 to -0.73]) and placebo (-2.34 ng/ml [95%CI: -2.95 to -1.73]) groups, with the placebo group having a slightly greater decrease (1.03 ng/ml [95%CI: 0.19 to 1.88]). Most (10 of 12) sub-study participants had normal synovial thickness scores at baseline. One participant had mild synovitis in each of the placebo and CL groups. Synovitis status was stable for all except two participants, one each in the CL and placebo group, whose synovitis score increased.

CONCLUSION

This is the first study that explored the effect of CL treatment on local and systemic inflammation using biochemical markers and CE-MRI outcomes on knee OA patients. Secondary analyses from this pilot study suggest that CL is unlikely to have clinically significant effects on systemic (inflammatory and cartilage) or local synovitis (CE-MRI) biomarkers compared to placebo. The mechanism of action for CL effect on pain remains unclear.

Inflammation-Driven Secretion Potential Is Upregulated in Osteoarthritic Fibroblast-Like Synoviocytes

Osteoarthritis (OA) is one of the most common joint pathologies and a major cause of disability among the population of developed countries. It manifests as a gradual degeneration of the cartilage and subchondral part of the bone, leading to joint damage. Recent studies indicate that not only the cells that make up the articular cartilage but also the synoviocytes, which build the membrane surrounding the joint, contribute to the development of OA. Therefore, the aim of the study was to determine the response to inflammatory factors of osteoarthritic synoviocytes and to identify proteins secreted by them that may influence the progression of OA. This study demonstrated that fibroblast-like synoviocytes of OA patients (FLS-OA) respond more strongly to pro-inflammatory stimulation than cells obtained from control patients (FLS). These changes were observed at the transcriptome level and subsequently confirmed by protein analysis. FLS-OA stimulated by pro-inflammatory factors [such as lipopolysaccharide (LPS) and tumor necrosis factor alpha (TNFα) were shown to secrete significantly more chemokines (CXCL6, CXCL10, and CXCL16) and growth factors [angiopoietin-like protein 1 (ANGPTL1), fibroblast growth factor 5 (FGF5), and insulin-like growth factor 2 (IGF2)] than control cells. Moreover, the translation of proteolytic enzymes [matrix metalloprotease 3 (MMP3), cathepsin K (CTSK), and cathepsin S (CTSS)] by FLS-OA is increased under inflammatory conditions. Our data indicate that the FLS of OA patients are functionally altered, resulting in an enhanced response to the presence of pro-inflammatory factors in the environment, manifested by the increased production of the previously mentioned proteins, which may promote further disease progression.

Effects of Non-Essential Amino Acids on Knee Joint Conditions in Adults: A Randomised, Double-Blind, Placebo-Controlled Trial

Joint problems impair performance during exercise and daily activities and influence quality of life. The present study aimed to examine the effects of a combination of six non-essential amino acids (6AA) on joint conditions in an adult population. A total of 50 participants aged between 20 and 64 years with joint discomfort but no diagnosed joint disorder were randomly and blindly assigned to a control or 6AA group. The 6AA group took 12 g of the non-essential amino acid formulation orally (4 g three times a day) and the control group took equivalent doses of a placebo. Each group maintained the daily dose for 12 weeks. Primary outcome measures were evaluated with the visual analogue scale (VAS), the Japanese Knee Osteoarthritis Measure (JKOM), and the Japanese Orthopaedic Association score (JOA). These tests were taken before the experiment began at 4 weeks and 12 weeks after the intervention. The results of the VAS indicated that 6AA improved joint pain, discomfort, and stiffness both during a resting state and during normal activity. Participants' scores on the JKOM and JOA also showed significant improvements in the group that had taken the 6AA supplement. These results demonstrate that 6AA improves symptoms of joint problems, such as pain, discomfort, stiffness, and difficulty in performing daily activities after 4 weeks of daily consumption.

Forward and reverse degradomics defines the proteolytic landscape of human knee osteoarthritic cartilage and the role of the serine protease HtrA1

OBJECTIVES

Proteolytic destruction of articular cartilage, a major pathogenic mechanism in osteoarthritis (OA), was not previously investigated by terminomics strategies. We defined the degradome of human knee OA cartilage and the contribution therein of the protease HtrA1 using Terminal Amine Isotopic Labeling of Substrates (TAILS).

DESIGN

Proteins from OA cartilage taken at knee arthroplasty (n = 6) or separately, from healthy cartilage incubated in triplicate with/without active HtrA1, were labeled at natural and proteolytically cleaved N-termini by reductive dimethylation, followed by trypsin digestion, enrichment of N-terminally labeled/blocked peptides, tandem mass spectrometry and positional peptide annotation to identify cleavage sites. Biglycan proteolysis by HtrA1 was validated biochemically and Amino-Terminal Oriented Mass Spectrometry of Substrates (ATOMS) was used to define the HtrA1 cleavage sites.

RESULTS

We identified 10,155 unique internal peptides from 2,162 proteins, suggesting at least 10,797 cleavage sites in OA cartilage. 7,635 internal peptides originated in 371 extracellular matrix/secreted components, many undergoing extensive proteolysis. Rampant ragging of protein termini suggested pervasive exopeptidase activity. HtrA1, the most abundant protease in OA cartilage, experimentally generated 323 cleavages in 109 cartilage proteins, accounting for 171 observed cleavages in the OA degradome. ATOMS identified HtrA1 cleavage sites in a selected substrate, biglycan, whose direct cleavage by HtrA1 was thus orthogonally validated.

CONCLUSIONS

OA cartilage demonstrates widespread proteolysis by endo- and exopeptidases. HtrA1 contributes broadly to cartilage proteolysis. Forward degradomics of OA cartilage together with reverse degradomics of proteases active in OA, e.g., HtrA1, can potentially fully annotate OA proteolytic pathways and provide new biomarkers.

Correlation between CD163 expression and resting pain in patients with hip osteoarthritis: Possible contribution of CD163+ monocytes/macrophages to pain pathogenesis

Expression of CD163, a scavenger receptor specifically expressed by monocytes and macrophages, is elevated in the synovial tissue of patients with knee osteoarthritis (OA) compared with healthy controls. However, the association between CD163 expression in the synovium and pain in OA patients is unclear. We investigated the correlation between synovial CD163 expression and resting and active pain levels in patients with hip osteoarthritis (HOA). To investigate the possible contribution of CD163+ subsets to pain pathogenesis, we compared pain-related cytokine expression and M1/M2 macrophage marker expression in CD163+ and CD163- cells. We performed flow cytometric analysis to study the CD163+ cell population. We also examined pain-related cytokine expression and M1/M2 macrophage marker expression on CD163+ CD14^high and CD163+ CD14^low cells using cell sorting. Synovial CD163 expression significantly correlated with resting pain levels (p = 0.006; R = 0.321), but not active pain levels (p = 0.155; R = 0.169). Expression of the M1 macrophage marker CD80 was significantly higher in CD163+ than CD163- cells (p = 0.010), as was the expression of M2 macrophage markers CD206 and IL10 (CD206, p = 0.014; IL10, p = 0.005), and TNFA and IL1B (TNFA, p = 0.002; IL1B, p = 0.001). TNFA expression was significantly higher in CD163+ CD14^low than CD163+ CD14^high cells, while IL1B, IL10, and CD206 expression were comparable among these subsets. Our findings suggest that CD163 expression is associated with higher resting pain scores. As TNF-α plays a role in the pain process, CD163+ CD14^low cells expressing TNFA may be a potent contributor to the pathogenesis of resting pain in HOA.

The Potential Role of Protease Systems in Hemophilic Arthropathy

Haemophilic arthropathy is characterised by joint damage following recurrent joint bleeds frequently observed in patients affected by the clotting disorder haemophilia. Joint bleeds or haemarthroses trigger inflammation in the synovial tissue which promotes damage to the articular cartilage. The plasminogen activation system is integral to fibrinolysis, and urokinase plasminogen activator or uPA in particular is strongly upregulated following haemarthroses. uPA is a serine protease that catalyses the production of plasmin, a broad-spectrum protease that can degrade fibrin as well as proteins of the joint extracellular matrix and cartilage. Both uPA and plasmin are able to proteolytically generate active forms of matrix metalloproteinases (MMPs). The MMPs are a family of >20 proteases that are secreted as inactive proenzymes and are activated extracellularly. MMPs are involved in degradation of all types of collagen and proteoglycans that constitute the extracellular matrix, which provides structural support to articular cartilage. The MMPs have an established role in joint destruction following rheumatoid arthritis (RA). They degrade cartilage and bone, indirectly promoting angiogenesis. MMPs are also implicated in the pathology of osteoarthritis (OA) characterized by degradation of the cartilage matrix that precipitates joint damage and deformity. HA shares a number of overlapping pathological characteristics with RA and OA. Here we discuss how the plasminogen activation system and MMPs might exacerbate joint damage in HA, lending insight into novel possible therapeutic targets to reduce co-morbidity of haemophilia.

Rhoifolin ameliorates osteoarthritis via the Nrf2/NF-κB axis: in vitro and in vivo experiments

OBJECTIVE

Osteoarthritis (OA) is an age-related degenerative disease accompanied by an increasing number of senescent cells and chronic low-grade inflammation. Rhoifolin (ROF) showed considerable inhibition to inflammation, but its role in chondrocyte senescence and OA progress has not been fully characterized. We aimed to evaluate the protective effects of ROF on OA through a series of in vitro and in vivo experiments.

METHODS

The role of ROF in the expression of senescence-associated secretory phenotype (SASP) factors was investigated using RT-qPCR, western blotting, and ELISA. Chondrocyte senescence was assessed by SA-β-gal staining. We applied molecular docking to screen candidate proteins regulated by ROF. Meanwhile, SASP factors and cellular senescence were further assessed after the transfection of Nrf2 siRNA. In the anterior cruciate ligament transection (ACLT) rat model, X-ray, hematoxylin-eosin (HE), and Masson's staining were performed to evaluate the therapeutic effects of ROF on OA.

RESULTS

We found that ROF inhibited SASP factors expression and senescence phenotype in IL-1β-treated chondrocytes. Furthermore, ROF suppressed IL-1β-induced activation of the NF-κB pathway cascades. Also, molecular docking and knock-down studies demonstrated that ROF might bind to Nrf2 to suppress the NF-κB pathway. In vivo, ROF ameliorated the OA process in the ACLT rat model.

CONCLUSIONS

ROF inhibits SASP factors expression and senescence phenotype in chondrocytes and ameliorates the progression of OA via the Nrf2/NF-κB axis, which supports ROF as a potential therapeutic agent for the treatment of OA.

The Effects of 21-Day General Rehabilitation after Hip or Knee Surgical Implantation on Plasma Levels of Selected Interleukins, VEGF, TNF-α, PDGF-BB, and Eotaxin-1

Rehabilitation in osteoarthritis (OA) patients aims to reduce joint pain and stiffness, preserve or improve joint mobility, and improve patients’ quality of life. This study evaluated the effects of the 21-day individually adjusted general rehabilitation program in 36 OA patients 90 days after hip or knee replacement on selected interleukins (IL) and cytokines using the Bio-Plex® Luminex® system. Serum concentrations of almost all selected anti/pro-inflammatory markers: IL-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, IL-15, and of some chemokines: macrophage inflammatory protein-1 alpha (MIP-1α/CCL3), and RANTES/CCL5, and of eotaxin-1/CCL11, the vascular endothelial growth factor (VEGF) significantly increased, whereas basic fibroblast growth factor (FGF basic) significantly decreased after the 21-day general rehabilitation. The levels of interferon-γ induced protein 10 (IP-10), MIP-1β/CCL4, macrophage/monocyte chemoattractant protein-1 (MCP-1/CCL2 (MCAF)), granulocyte macrophage-colony stimulating factor (GM-CSF), platelet-derived growth factor-BB (PDGF-BB), and granulocyte colony-stimulating factor (G-CSF) remained unchanged. There were no changes in pro-inflammatory cytokines levels: tumor necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ), and IL-12 (p70)) after the 21-day general rehabilitation, indicating the stable and controlled inflammatory status of osteoarthritis patients. Significantly higher levels of anti-inflammatory factors after 21 days of moderate physical activity confirm the beneficial outcome of the applied therapy. The increased level of IL-6 after the rehabilitation may reflect its anti-inflammatory effect in osteoarthritis patients.

Role of Platelets in Osteoarthritis-Updated Systematic Review and Meta-Analysis on the Role of Platelet-Rich Plasma in Osteoarthritis

Platelets are an essential component of hemostasis, with an increasing role in host inflammatory processes in injured tissues. The reaction between receptors and vascular endothelial cells results in the recruitment of platelets in the immune response pathway. The aim of the present review is to describe the role of platelets in osteoarthritis. Platelets induce secretion of biological substances, many of which are key players in the inflammatory response in osteoarthritis. Molecules involved in cartilage degeneration, or being markers of inflammation in osteoarthritis, are cytokines, such as tumor necrosis factor α (TNFα), interleukins (IL), type II collagen, aggrecan, and metalloproteinases. Surprisingly, platelets may also be used as a treatment modality for osteoarthritis. Multiple randomized controlled trials included in our systematic review and meta-analyses prove the effectiveness of platelet-rich plasma (PRP) as a minimally invasive method of pain alleviation in osteoarthritis treatment.

Shoulder Lesions Do Not Increase Inflammatory Biomarkers in Patients Undergoing Surgery for Glenohumeral Instability: An Exploratory Study

Circulating protein biomarkers have demonstrated utility as a diagnostic tool in predicting musculoskeletal disease severity, but their utility in the evaluation of shoulder lesions associated with shoulder instability is unknown. Thus, the purpose of this exploratory study was to determine whether preoperative biomarkers of cartilage turnover and inflammation are associated with specific shoulder lesions in shoulder instability. Thirty-three patients (29.9 ± 9.4 years of age, 4.5 ± 4.7 dislocations) undergoing surgical treatment for shoulder instability were assessed for the presence or absence of associated shoulder lesions. Biomarkers including cartilage oligomeric matrix protein (COMP), C-reactive protein (HS-CRP), interleukin-8 (IL-8), and macrophage inflammatory protein-1β (MIP-1b) were collected at the time of surgery. Patients with Hill-Sachs lesions had a 31% increase in COMP plasma levels (p=0.046). No other significant differences were observed for COMP, HS-CRP, IL-8, and MIP-1b with any shoulder lesion including Hill-Sachs lesions, capsular injuries, bony Bankart lesions, and SLAP lesions. In conclusion, inflammatory biomarkers including HS-CRP, IL-8, and MIP-1b were not associated with specific shoulder lesions, while biomarkers of cartilage turnover (COMP) were only elevated in Hill-Sachs lesions. These findings suggest that these biomarkers may have limited utility as prognostic indicators in patients with shoulder instability, though large-scale and longitudinal studies are still necessary.

Joint Dysfunctionality Alleviation along with Systemic Inflammation Reduction following Arthrocen Treatment in Patients with Knee Osteoarthritis: A Randomized Double-Blind Placebo-Controlled Clinical Trial

Background and objectives: Many mediators and cytokines are involved in the pathogenesis of osteoarthritis (OA). Some of these cytokines are spontaneously expressed by cultured fibroblast-like synoviocytes. Therefore, using serum samples, the efficacy and the effects of avocado/soy unsaponifiables, ASU, (Arthrocen) on cytokine changes were assessed in patients with knee OA (KOA). Materials and Methods: Experimental procedure: A randomized, double-blind, placebo-controlled clinical trial was conducted on patients with a diagnosis of mild to moderate OA who received either Arthrocen 300 mg/day (n = 61) or placebo (n = 58) for 3 months. Data collection was performed using questionnaires including the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), 20-item short form survey (SF-20), Lequesne index of severity for osteoarthritis of the knee (LISOK), and three visual analog scales (VASs) as pain quality indices. The serum levels of interleukins 2 (IL-2), IL-4, IL-10, IL-17α, and TNF-α were measured using an ELISA reader. Results: Both quality of life indices, pain sensation and scored by specialists (as VASs), respectively, including WOMAC and SF-20, as well as joint dysfunctionality symptoms assessed by physicians were significantly improved (p < 0.05) in OA patients receiving Arthrocen. The serum levels of anti-inflammatory interleukins 4 and 10 were also augmented, while levels of inflammatory IL-17 and TNF-ɑ cytokines were decreased significantly (p < 0.05) compared with the control groups during the 3- and 6-month treatment. Conclusions: Arthrocen consumption may increase the quality of life in OA patients through amelioration of inflammation and improvement of functional activities without any adverse effects in the long term.

A Single Injection of Amniotic Suspension Allograft Is Safe and Effective for Treatment of Mild to Moderate Hip Osteoarthritis: A Prospective Study

PURPOSE

The purpose of our study was to examine the effects of a commercially available amniotic suspension allograft (ASA) (ReNu, Organogenesis, Canton, MA) in a patient population with moderate osteoarthritis of the hip.

METHODS

Ten patients with symptomatic hip osteoarthritis, defined as Tonnis grade 1 or 2 on radiographic examination, were prospectively enrolled. Each patient received a single image-guided injection of ASA into the hip joint. Patient-reported outcomes measures, including the 12-item International Hip Outcome Tool, Modified Harris Hip Score, and Single Assessment Numeric Evaluation scores were recorded at baseline, 6 months, and 12 months postinjection. A linear regression model was performed to detect differences in outcome scores from baseline.

RESULTS

Nine patients had complete 12-month data available for analysis. One patient failed treatment and underwent arthroplasty at 2 months postinjection. The cohort includes 5 males and 4 females, aged 47-67. International Hip Outcome Tool scores demonstrated a significant improvement between baseline and 12 months (P = .02). Single Assessment Numeric Evaluation scores demonstrated a significant difference between baseline and 6 months (P < .01), as well as between baseline and 12 months (P < .01). Modified Harris Hip Scores demonstrated a significant difference between baseline and 6 months (P = .02) and between baseline and 12 months (P = .01). There were no major adverse events in the course of the study period.

CONCLUSION

This study demonstrates promising results for relief of pain and improvement in patient-reported outcomes with intra-articular ASA in patients with moderate osteoarthritis of the hip for up to one year, although the exact mechanism of action remains unknown. LEVEL OF EVIDENCE: IV, case series.

Effect of intravenous tiludronate disodium administration on the radiographic progression of osteoarthritis of the fetlock joint in Standardbred racehorses

OBJECTIVE

To compare the effects of tiludronate disodium and 3 other medical treatments on clinical and radiographic findings and biomarkers of disease progression in horses with osteoarthritis of the fetlock joint.

ANIMALS

100 Standardbred racehorses with spontaneous traumatic injury of the fetlock joint.

PROCEDURES

Horses were retrospectively grouped by whether they received tiludronate IV or triamcinolone acetonide and hyaluronan, polysulfated glycosaminoglycan, or interleukin-1 receptor antagonist protein intra-articularly. Data were collected on clinical, radiographic, and ultrasonographic findings and results for serum and synovial samples obtained before and 6 months after treatment. Lameness score, joint flexion test response, radiographic score, serum concentrations of tumor necrosis factor-α and carboxy-terminal telopeptides of collagen types I and II (CTX-I and II, respectively), and synovial fluid concentrations of interleukin-1β, prostaglandin E₂, and CTX-II were compared among treatments.

RESULTS

All treatments resulted in a significant improvement in lameness score and joint flexion test response at 6 months. In horses that received triamcinolone acetonide and hyaluronan, synovial fluid interleukin-1β, prostaglandin E₂, and CTX-II concentrations decreased after treatment, suggesting this treatment inhibited progression of hyaline cartilage degeneration and inflammatory processes. Horses that received tiludronate were the only group that had a decrease in radiographic score and serum CTX-I concentration after treatment, supporting the effect of tiludronate on bone metabolism. Tiludronate treatment was also followed by increases in serum and synovial fluid concentrations of CTX-II, a marker of cartilage damage.

CONCLUSIONS AND CLINICAL RELEVANCE

Tiludronate appeared to inhibit the radiographic progression of osteoarthritis in high-motion joints of racehorses at 6 months after treatment by inhibiting subchondral bone remodeling. Whether this effect was associated with a worsening of progressive cartilage damage remains to be ascertained.

Randomised, double-blind comparison of a fixed co-formulation of intra-articular polynucleotides and hyaluronic acid versus hyaluronic acid alone in the treatment of knee osteoarthritis: two-year follow-up

Background

A first-year interim analysis of this two-year study suggested that intra-articular injections of highly purified, natural-origin polynucleotides and hyaluronic acid (HA) as a fixed combination (PNHA) might improve knee function and joint pain more effectively than HA alone in patients with knee osteoarthritis (OA). The purpose of the second-year analysis herein described was to verify whether the first-year interim outcomes persist over the whole two-year period.

Methods

Randomised, double-blind, HA-controlled clinical trial in 100 knee OA patients (98 randomised, 79 completing the study) in a high-specialisation tertiary care setting. The hypothesised difference of efficacy between PNHA and HA for the original sample size estimate is 20%. Treatment cycle: three intra-articular knee injections of either PNHA or HA, at baseline and weekly for two weeks. Evaluations: Western Ontario and McMaster Universities (WOMAC) score and Knee Society Score (KSS) as, respectively, primary and secondary endpoints, evaluated at baseline and after 2, 6, 12, and 24 months; synovial fluid levels of mediators (at baseline and the end of the treatment cycle). Adverse effects investigated at each control visit. Statistical analysis: Kruskal-Wallis test for independent samples (nonparametric one-way analysis of variance) after correction of means for age, Body Mass Index and Kellgren-Lawrence grade. If significant, pairwise post-hoc Sidak multiple comparisons.

Results

KSS total score and KSS pain item: significant improvement in both groups, with significantly more pain improvement in patients treated with PNHA (2-point reduction) than HA (1-point reduction). Both groups experienced significant long-term reductions in WOMAC total scores: significantly stronger in PNHA-treated patients after 24 months with a steady difference of 16% favouring PNHA in WOMAC pain subscore. No clinically significant adverse events in either group.

Conclusions

The outcomes of the 2-year study confirmed that a short cycle of intra-articular treatment (3 weekly double-blind injections) with polynucleotides (long-acting viscosupplementation properties, chondrocyte activation, pain-relieving properties) in fixed combination with high molecular weight hyaluronic acid is more effective in improving knee function and pain in knee OA patients than HA alone. PNHA may be elective for viscosupplementation in knee OA patients with fastidious and resistant pain and worsening disease.

Trial registration

NCT02417610.

Registration, 15/04/2015.

ClinicalTrials.gov database link:

A matrix metalloproteinase-generated neoepitope of CRP can identify knee and multi-joint inflammation in osteoarthritis

OBJECTIVE

To compare C-reactive protein (CRP) and matrix metalloproteinase-generated neoepitope of CRP (CRPM) as biomarkers of inflammation and radiographic severity in patients with knee osteoarthritis.

METHODS

Participants with symptomatic osteoarthritis (n=25) of at least one knee underwent knee radiographic imaging and radionuclide etarfolatide imaging to quantify inflammation of the knees and other appendicular joints. For purposes of statistical analysis, semi-quantitative etarfolatide and radiographic imaging scores were summed across the knees; etarfolatide scores were also summed across all joints to provide a multi-joint synovitis measure. Multiple inflammation and collagen-related biomarkers were measured by ELISA including CRP, CRPM, MMP-generated neoepitopes of type I collagen and type III collagen in serum (n=25), and CD163 in serum (n=25) and synovial fluid (n=18).

RESULTS

BMI was associated with CRP (p=0.001), but not CRPM (p=0.753). Adjusting for BMI, CRP was associated with radiographic knee osteophyte score (p=0.002), while CRPM was associated with synovitis of the knee (p=0.017), synovitis of multiple joints (p=0.008), and macrophage marker CD163 in serum (p=0.009) and synovial fluid (p=0.03). CRP correlated with MMP-generated neoepitope of type I collagen in serum (p=0.045), and CRPM correlated with MMP-generated neoepitope of type III collagen in serum (p<0.0001). No biomarkers correlated with age, knee pain, or WOMAC pain.

CONCLUSIONS

To our knowledge, this is the first time that CRPM has been shown to be associated with knee and multi-joint inflammation based on objective imaging (etarfolatide) and biomarker (CD163) measures. These results demonstrate the capability of biomarker measurements to reflect complex biological processes and for neoepitope markers to more distinctly reflect acute processes than their precursor proteins. CRPM is a promising biomarker of local and systemic inflammation in knee OA that is associated with cartilage degradation and is independent of BMI. CRPM is a potential molecular biomarker alternative to etarfolatide imaging for quantitative assessment of joint inflammation.

NLRC5 attenuates inflammatory response in IL-1β-stimulated human osteoarthritis chondrocytes through the NF-κB signaling pathway

NOD-like receptor family caspase recruitment domain family domain containing 5 (NLRC5) has been found to be a critical mediator of inflammatory response. However, the role of NLRC5 in osteoarthritis (OA) has not been reported. Our results showed that NLRC5 was down-regulated by IL-1β induction in chondrocytes. Overexpression of NLRC5 in chondrocytes significantly suppressed IL-1β-induced inflammatory response through inhibiting the production of multiple inflammatory mediators including inducible nitric oxide synthases (iNOS), and cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), NO, TNF-α and IL-6, as well matrix metalloproteinase 3 (MMP-3) and MMP-13. Consistently, NLRC5 knockdown exhibited opposite effects on the production of these inflammatory mediators in IL-1β-induced chondrocytes. Furthermore, overexpression of NLRC5 increased the IĸBα expression, while decreased the p-p65 expression, indicating that NLRC5 inhibited the activation of NF-κB signaling. Additionally, inhibition of NF-κB by PDTC mitigated the si-NLRC5-mediated promotion of IL-1β-induced inflammatory injury in chondrocytes. Finally, NLRC5 treatment ameliorated cartilage degeneration in an OA model in rats. Taken together, these findings revealed that NLRC5 attenuated IL-1β-induced inflammatory injury in chondrocytes through regulating the NF-κB signaling.

Correlation between serum pro inflammatory cytokines and clinical scores of knee osteoarthritic patients using resveratrol as a supplementary therapy with meloxicam

OBJECTIVE:

The objective of this study was to analyze the associations between the pro-inflammatory markers with the clinical outcomes of knee osteoarthritis (OA) in patients using resveratrol as an add-on treatment with meloxicam.

MATERIALS AND METHODS:

This was a double-blind controlled clinical investigation, with 110 eligible patients with OA assigned randomly to receive 15 mg a day meloxicam with either resveratrol 500 mg a day or placebo for 90 days. The standard tools for assessment of pain severity and physical functions were utilized. The tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 in the blood were evaluated. Spearman's correlation coefficient test was used to determine the significance of correlations.

RESULTS:

The regression analysis to determine the correlation between reductions of the inflammatory biomarkers with the amelioration of the clinical scores showed a nonsignificant weak correlation between these variables. Total clinical scores of each assessment tool that was used “Knee Injury and OA Outcome Score (KOOS) and WOMAC” displayed a weak and nonsignificant correlation with TNF-α, IL-1β blood level. The Spearman's correlation shows a relatively nonsignificant association between IL-6 levels and KOOS, WOMAC, and Visual Analog Scale scores after incorporating resveratrol as an adjuvant with meloxicam for 90 days.

CONCLUSION:

A weak and nonsignificant correlation between serum biomarkers and the clinical outcomes has been suggested in patients with painful knee OA treated with meloxicam and resveratrol.

Optimization of Lyophilized Hyperacute Serum (HAS) as a Regenerative Therapeutic in Osteoarthritis

Hyperacute serum (HAS) is a blood derivative product that promotes the proliferation of various cell types and controls inflammation in vitro. The aim of this study is to investigate the regenerative potential of different formulations of HAS, including lyophilized and hyaluronic acid combined versions, to obtain a stable and standardized therapeutic in osteoarthritis (OA), which may be able to overcome the variability limitations of platelet-rich plasma (PRP). Primary human osteoarthritic chondrocytes were used for testing cellular viability and gene expression of OA-related genes. Moreover, a co-culture of human explants of cartilage, bone and synovium under inflammatory conditions was used for investigating the inflammatory control capacities of the different therapeutics. In this study, one formulation of lyophilized HAS achieved the high cell viability rates of liquid HAS and PRP. Gene expression analysis showed that HAS induced higher Col1a1 expression than PRP. Cytokine quantification from supernatant fluids revealed that HAS treatment of inflamed co-cultures significantly reduced levels of IL-5, IL-15, IL-2, TNFα, IL-7 and IL-12. To conclude, lyophilized HAS is a stable and standardized therapeutic with high potential in joint regeneration.

A chondroitin sulfate based injectable hydrogel for delivery of stem cells in cartilage regeneration

Chondroitin sulfate (CS), as a popular material for cartilage tissue engineering scaffolds, has been extensively studied and reported for its safety and excellent biocompatibility. However, the rapid degradation of pure CS scaffolds has brought a challenge to regenerate neo-tissue similar to natural articular cartilage effectively. Meanwhile, the poly(ethene glycol) (PEG) -based biopolymer is frequently applied as a structural constituent material because of its remarkable mechanical properties, long-lasting in vivo stability, and hypo-immunity. Here, we report that the combination of CS and hyperbranched multifunctional PEG copolymer (HB-PEG) could synergistically promote cartilage repair. The thiol functionalised CS (CS-SH)/HB-PEG hydrogel scaffolds were fabricated via thiol-ene reaction, which exhibits rapid gelation, excellent mechanical properties and prolonged degradation properties. We found that rat adipose-derived mesenchymal stem cells presented great cell viability and improved chondrogenesis in CS-SH/HB-PEG hydrogels. Moreover, the injectable hydrogel scaffolds reduced stem cell inflammatory response, consistent with the well-documented anti-inflammatory activities of CS.

Clusterin secretion is attenuated by the proinflammatory cytokines interleukin-1β and tumor necrosis factor-α in models of cartilage degradation

The protein clusterin has been implicated in the molecular alterations that occur in articular cartilage during osteoarthritis (OA). Clusterin exists in two isoforms with opposing functions, and their roles in cartilage have not been explored. The secreted form of clusterin (sCLU) is a cytoprotective extracellular chaperone that prevents protein aggregation, enhances cell proliferation and promotes viability, whereas nuclear clusterin acts as a pro-death signal. Therefore, these two clusterin isoforms may be putative molecular markers of repair and catabolic responses in cartilage and the ratio between them may be important. In this study, we focused on sCLU and used established, pathophysiologically relevant, in vitro models to understand its role in cytokine-stimulated cartilage degradation. The secretome of equine cartilage explants, osteochondral biopsies and isolated unpassaged chondrocytes was analyzed by western blotting for released sCLU, cartilage oligomeric protein (COMP) and matrix metalloproteinases (MMP) 3 and 13, following treatment with the proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α. Release of sulfated glycosaminoglycans (sGAG) was determined using the dimethylmethylene blue assay. Clusterin messenger RNA (mRNA) expression was quantified by quantitative real-time polymerase chain reaction. MMP-3, MMP-13, COMP, and sGAG release from explants and osteochondral biopsies was elevated with cytokine treatment, confirming cartilage degradation in these models. sCLU release was attenuated with cytokine treatment in all models, potentially limiting its cytoprotective function. Clusterin mRNA expression was down-regulated 7-days post cytokine stimulation. These observations implicate sCLU in catabolic responses of chondrocytes, but further studies are required to evaluate its role in OA and its potential as an investigative biomarker.

Mechanistic Targets and Nutritionally Relevant Intervention Strategies to Break Obesity-Breast Cancer Links

The worldwide prevalence of overweight and obesity has tripled since 1975. In the United States, the percentage of adults who are obese exceeds 42.5%. Individuals with obesity often display multiple metabolic perturbations, such as insulin resistance and persistent inflammation, which can suppress the immune system. These alterations in homeostatic mechanisms underlie the clinical parameters of metabolic syndrome, an established risk factor for many cancers, including breast cancer. Within the growth-promoting, proinflammatory milieu of the obese state, crosstalk between adipocytes, immune cells and breast epithelial cells occurs via obesity-associated hormones, angiogenic factors, cytokines, and other mediators that can enhance breast cancer risk and/or progression. This review synthesizes evidence on the biological mechanisms underlying obesity-breast cancer links, with emphasis on emerging mechanism-based interventions in the context of nutrition, using modifiable elements of diet alone or paired with physical activity, to reduce the burden of obesity on breast cancer.

Recent developments in natural and synthetic polymeric drug delivery systems used for the treatment of osteoarthritis

Osteoarthritis (OA), is a common musculoskeletal disorder that will progressively increase in older populations and is expected to be the most dominant cause of disability in the world population by 2030. The progression of OA is controlled by a multi-factorial pathway that has not been completely elucidated and understood yet. However, over the years, research efforts have provided a significant understanding of some of the processes contributing to the progression of OA. Both cartilage and bone degradation processes induce articular cells to produce inflammatory mediators that produce proinflammatory cytokines that block the synthesis of collagen type II and aggrecan, the major components of cartilage. Systemic administration and intraarticular injection of anti-inflammatory agents are the first-line treatments of OA. However, small anti-inflammatory molecules are rapidly cleared from the joint cavity which limits their therapeutic efficacy. To palliate this strong technological drawback, different types of polymeric materials such as microparticles, nanoparticles, and hydrogels, have been examined as drug carriers for the delivery of therapeutic agents to articular joints. The main purpose of this review is to provide a summary of recent developments in natural and synthetic polymeric drug delivery systems for the delivery of anti-inflammatory agents to arthritic joints. Furthermore, this review provides an overview of the design rules that have been proposed so far for the development of drug carriers used in OA therapy. Overall it is difficult to state clearly which polymeric platform is the most efficient one because many advantages and disadvantages could be pointed to both natural and synthetic formulations. That requires further research in the near future.

Biomarkers of Joint Damage in Osteoarthritis: Current Status and Future Directions

Osteoarthritis (OA) is a disease of the whole joint organ, characterized by the loss of cartilage, and structural changes in bone including the formation of osteophytes, causing disability and loss of function. It is also associated with systemic mediators and low-grade inflammation. Currently, there is negligible/no availability of specific biomarkers that can be used to facilitate the diagnosis and treatment of OA. The most unmet clinical need is, however, related to the monitoring of disease progression over a short period that can be used in clinical trials. In this review, the value of biomarkers identified over the past decade has been highlighted. These biomarkers are associated with the synthesis and breakdown of cartilage, including collagenous and noncollagenous biomarkers, inflammatory and anti-inflammatory biomarkers, expressed in the biological fluid such as serum, synovial fluid, and urine. Broad validation of novel and clinically applicable biomarkers and their involvement in the pathways are particularly needed for early-stage diagnosis, monitoring disease progression, and severity and examining new drugs to mitigate the effects of this highly prevalent and debilitating condition.

Autologous protein solution as selective treatment for advanced patellofemoral osteoarthritis in the middle-aged female patient: 54% response rate at 1 year follow-up

PURPOSE

The study wanted to investigate the benefit, durability and safety of autologous protein solution (APS) injection(s) in a middle-aged female-only cohort suffering predominantly from patellofemoral osteoarthritis.

METHODS

Fifty females (aged 50.4 ± 6.5) with mainly moderate-severe (86%) patellofemoral cartilage wear (PFCW) were treated with a unilateral intra-articular APS injection. The KOOS, NRS, Kujala, UCLA and EQ-5D were assessed at baseline and 1, 3, 6, and 12 months post-injection. Therapeutic response rate (TRR) was based on KOOS pain improvement > 10 points. Absolute improvement for, respectively, therapy responders and non-responders was determined. Second APS injection was administered if improvement was deemed insufficient by the patient after 3 months.

RESULTS

The TRR remained stable averaging to 53.7% at final follow-up with subjects improving overall from 40.3 ± 18.7 to 57.3 ± 24.8 points on KOOS pain (p = 0.0002) and from 48.4 ± 13.0 to 56.3 ± 18.1 points on Kujala (p = 0.0203) at 12 months. Significant improvement was observed for the other KOOS subscales and NRS at each follow-up. In absolute values, APS responders improved with 30.5 ± 11.4 points on KOOS pain at 12 months. In contrast, non-responders deteriorated with 5.9 ± 8.9 points relative to baseline. A second APS injection was administered in 28 subjects. Patients with definite synovitis improved more on KOOS symptoms (p = 0.017) and KOOS ADL (p = 0.037) at 12 months compared to non-synovitis subjects. Mild-moderate arthralgia (46%) and effusion (29%) were commonly observed during the first month post-injection.

CONCLUSION

This study evidenced a 54% response rate at 12 months to a single or second APS injection in a middle-aged female population with advanced patellofemoral cartilage wear. Moderate temporary flares can be expected without affecting clinical outcomes. Second APS injection has low efficacy in initially poor responding patients after 3 months. Major synovitis on baseline MRI appeared to be a beneficial prognosticator for pain relief and functional improvement after APS.

LEVEL OF EVIDENCE

IV.

The gut microbiome-joint connection: implications in osteoarthritis

Supplemental Digital Content is available in the text

Osteoarthritis is a debilitating disease leading to joint degeneration, inflammation, pain, and disability. Despite efforts to develop a disease modifying treatment, the only accepted and available clinical approaches involve palliation. Although many factors contribute to the development of osteoarthritis, the gut microbiome has recently emerged as an important pathogenic factor in osteoarthritis initiation and progression. This review examines the literature to date regarding the link between the gut microbiome and osteoarthritis.

Circ_0045714 alleviates TNF-α-induced chondrocyte injury and extracellular matrix degradation through miR-218-5p/HRAS axis

Emerging evidence suggests that dysregulated circular RNAs (circRNAs) play a pivotal role in osteoarthritis (OA). Circ_0045714 is a functional circRNAs, and has been revealed to involve in the process of OA. However, the molecular mechanisms by which circ_0045714 regulates OA progression are not thoroughly elucidated. Circ_0045714 expression was decreased in OA and TNF-α-induced chondrocytes, ectopic overexpression of circ_0045714 abolished TNF-α-induced cell apoptosis, inflammation, extracellular matrix (ECM) degradation promotion and proliferation inhibition. In a mechanical study, circ_0045714 targeted miR-218-5p, and miR-218-5p overexpression reversed the effects of circ_0045714 on TNF-α-induced chondrocytes. Besides that, HRAS was a target of miR-218-5p, and HRAS knockdown attenuated the protective effects of miR-218-5p inhibition on TNF-α-induced chondrocyte dysfunction. Additionally, circ_0045714 could regulate HRAS expression via miR-218-5p in chondrocytes. Up-regulation of circ_0045714 suppressed TNF-α-induced chondrocyte growth inhibition, inflammation, and ECM degradation via miR-218-5p/HRAS axis, suggesting a novel insight into the pathogenesis of OA and the potential protective role of circ_0045714 in the occurrence and development of OA.

Prolotherapy agent P2G is associated with upregulation of fibroblast growth factor-2 genetic expression in vitro

Purpose

Osteoarthritis (OA) is a prevalent, progressively degenerative disease. Researchers have rigorously documented clinical improvement in participants receiving prolotherapy for OA. The mechanism of action is unknown; therefore, basic science studies are required. One hypothesized mechanism is that prolotherapy stimulates tissue proliferation, including that of cartilage. Accordingly, this in vitro study examines whether the prolotherapy agent phenol-glycerin-glucose (P2G) is associated with upregulation of proliferation-enhancing cytokines, primarily fibroblast growth factor-2 (FGF-2).

Methods

Murine MC3T3-E1 cells were cultured in a nonconfluent state to retain an undifferentiated osteochondroprogenic status. A limitation of MC3T3-E1 cells is that they do not fully reproduce primary human chondrocyte phenotypes; however, they are useful for modeling cartilage regeneration in vitro due to their greater phenotypic stability than primary cells. Two experiments were conducted: one in duplicate and one in triplicate. Treatment consisted of phenol-glycerin-glucose (P2G, final concentration of 1.5%). The results were assessed by quantitative Reverse Transcriptase-Polymerase Chain Reaction (qRT-PCR) to detect mRNA expression of the FGF-2, IGF-1, CCND-1 (Cyclin-D), TGF-β1, AKT, STAT1, and BMP2 genes.

Results

P2G - treated preosteoblasts expressed higher levels of FGF-2 than water controls (hour 24, p < 0.001; hour 30, p < 0.05; hour 38, p < 0.01). Additionally, CCND-1 upregulation was observed (p < 0.05), possibly as a cellular response to FGF-2 upregulation.

Conclusions

The prolotherapy agent P2G appears to be associated with upregulation of the cartilage cell proliferation enhancer cytokine FGF-2, suggesting an independent effect of P2G consistent with clinical evidence. Further study investigating the effect of prolotherapy agents on cellular proliferation and cartilage regeneration is warranted.

Concerted actions by MMPs, ADAMTS and serine proteases during remodeling of the cartilage callus into bone during osseointegration of hip implants

INTRODUCTION

Although the number of patients undergoing total hip arthroplasty is constantly on the rise, we only have limited knowledge of the molecular mechanisms necessary for successful osseointegration of implants or the reasons why some fail. Understanding the spatiotemporal characteristics of signaling pathways involved in bone healing of implants is therefore of particular importance for our ability to identify factors causing implants to fail. The current study investigated the role of three families of proteases, i.e. MMPs (matrix metalloproteinases), ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) and serine proteases, as well as their endogenous inhibitors during osseointegration of hip implants that have endured two decades of use without clinical or radiological signs of loosening.

MATERIALS AND METHODS

Twenty-four patients that had undergone primary THA due to one-sided osteoarthritis (OA) were monitored during 18 years (Y) with repeated measurements of plasma biomarkers, clinical variables and radiographs. All implants were clinically and radiographically well-fixed throughout the follow-up. Eighty-one healthy donors divided in three gender and age-matched groups and twenty OA patients awaiting THA, served as controls. Plasma was analyzed for MMP-1, -2, -3, -8, -9, -10, -13, -14, tissue inhibitor of metalloproteinase (TIMP)-1, -2, -3, ADAMTS4, ADAMTS5, the serine proteases neutrophil elastase (NE), proteinase 3 (PR3) and their endogenous inhibitors, secretory leucocyte proteinase inhibitor (SLPI), trappin-2/elafin and serpina1 (α-1 antitrypsin). Cartilage turnover was monitored using two markers of cartilage synthesis, type II procollagen and PIICP (procollagen II C-terminal propeptide), and two markers of cartilage degradation, CTX-II (C-terminal telopeptide fragments of type II collagen) and split products of aggrecan (G1-IGD-G2).

RESULTS

MMP-1, MMP-9, ADAMTS4, NE and PR3 were above healthy in presurgery OA patients but returned to the level of healthy within 6 weeks (W) after surgery. MMPs and serine proteases were counter-regulated during this phase by TIMP-1, SLPI and trappin-2/elafin. Type II procollagen, PIICP and CTX-II increased to a peak 6 W after surgery with a gradual return to the level of controls within weeks. Significant increases by MMP-8, MMP-9, ADAMTS4, ADAMTS5, NE, PR3 and the protease inhibitors, TIMP-3 and serpina1, were seen 5 Y after hip arthroplasty paralleled by a sharp increase in the levels of the cartilage degradation markers, CTX-II and G1-IGD-G2. All the above mediators were normalized before 18 Y, except MMP-1 and MMP-9 that remained above healthy at 18 Y. MMP-14 increased immediately after surgery and remained elevated until 5 Y postsurgery before returning to the level of controls at 7 Y.

CONCLUSION

Notwithstanding temporal differences, the molecular processes of bone repair in arthroplasty patients show great spatial similarities with the classical phases of fracture repair as previously shown in animal models. Cartilagenous callus, produced and remodeled early after hip arthroplasty, is replaced with bone 5 Y to7 Y after surgery by the concerted actions of MMP-8, MMP-9, ADAMTS4, ADAMTS5, NE and PR3, thus suggesting that a complex regulatory cross-talk may exist between different families of proteases during this transitional phase of cartilage degradation. Regulation and fine-tuning of cartilage remodeling by MMPs and ADAMTS is controlled by TIMP-3 whereas serine proteases are regulated by serpina1. Increased MMP-1 and MMP-9 beyond 10Y post-THA support a role during coupled bone remodeling.

The Synovium Attenuates Cartilage Degeneration in KOA through Activation of the Smad2/3-Runx1 Cascade and Chondrogenesis-related miRNAs

Knee osteoarthritis (KOA) is a highly prevalent disabling joint disease in aged people. Progressive cartilage degradation is the hallmark of KOA, but its deeper mechanism remains unclear. Substantial evidence indicates the importance of the synovium for joint homeostasis. The present study aimed to determine whether the synovium regulates cartilage metabolism through chondrogenesis-related microRNAs (miRNAs) in the KOA microenvironment. Clinical sample testing and in vitro cell experiments screened out miR-455 and miR-210 as effective miRNAs. The levels of both were significantly reduced in KOA cartilage but increased in KOA synovial fluid compared with controls. We further revealed that transforming growth factor β1 (TGF-β1) can significantly upregulate miR-455 and miR-210 expression in synoviocytes. The upregulated miRNAs can be secreted into the extracellular environment and prevent cartilage degeneration. Through bioinformatics and in vitro experiments, we found that Runx1 can bind to the promoter regions of miR-455 and miR-210 and enhance their transcription in TGF-β1-treated synoviocytes. Collectively, our findings demonstrate a protective effect of the synovium against cartilage degeneration mediated by chondrogenesis-related miRNAs, which suggests that Runx1 is a potential target for KOA therapy.

LncRNA NEAT1 regulates chondrocyte proliferation and apoptosis via targeting miR-543/PLA2G4A axis

Osteoarthritis (OA), which is characterized by articular cartilage degeneration, shows a gradually increasing incidence with age. This study explored the molecular mechanism underlying the proliferation and apoptosis of chondrocytes during OA progression. In this study, chondrocytes were isolated from human knee cartilages. The targeted relationship among nuclear enriched abundant transcript 1 (NEAT1), microRNA-543 (miR-543) and PLA2G4A was predicted on TargetScan V7.2 and starBase and validated by performing dual-luciferase reporter assay. High-expressed NEAT1 was detected in OA cartilage and chondrocytes. NEAT1 was negatively correlated with miR-543 and was low-expressed in OA cartilage and PLA2G4A was negatively correlated with miR-543 and was high-expressed in OA cartilage. In OA chondrocytes, the overexpressed NEAT1 inhibited the expressions of p-Akt1 and Bcl-2 and upregulated that of matrix metalloprotease (MMP)-3, MMP-9, MMP-13, interleukin (IL)-6 and IL-8, but such effects of overexpressed NEAT1 were reversed by miR-543 mimic. SiRNA-NEAT1 exerted an opposite effect to NEAT1 overexpression on OA chondrocytes, but this could be reversed by miR-543 inhibitor. The effect of PLA2G4A overexpression was the opposite to miR-543 mimic on OA chondrocytes. In conclusion, NEAT1 could sponge miR-543 to induce PLA2G4A expression, inhibit chondrocyte proliferation and promote apoptosis.

Health effects of a low-inflammatory diet in adults with arthritis: a systematic review and meta-analysis

The aim is to systematically assess the health impact of a low-inflammatory diet intervention (full-diet or supplement), compared to usual diet or other dietary interventions, on weight change, inflammatory biomarkers, joint symptoms, and quality of life in adults with osteoarthritis, rheumatoid arthritis or seronegative arthropathy (psoriatic, reactive, ankylosing spondylitis or IBD-related), on outcomes assessed in prospective studies within 6 months of intervention commencement (PROSPERO CRD42019136567). Search of multiple electronic library databases from inception to July 2019, supplemented by grey literature searches, for randomised and prospective trials assessing the above objective. After exclusion of 446 ineligible studies, five randomised and two prospective trials involving 468 participants with either osteoarthritis or rheumatoid arthritis were included. GRADE assessment for all outcomes was very low. Meta-analyses produced the following standardised mean differences (SMD) and 95 % confidence interval (CI) 2-4 months following commencement of the diets favouring the low-inflammatory diet: weight SMD -0⋅45 (CI -0⋅71, -0⋅18); inflammatory biomarkers SMD -2⋅33 (CI -3⋅82, -0⋅84). No significant effects were found for physical function (SMD -0⋅62; CI -1⋅39, 0⋅14), general health (SMD 0⋅89; CI -0⋅39, 2⋅16) and joint pain (SMD -0⋅98; CI -2⋅90, 0⋅93). In most studies, the quality of dietary intervention (dietitian input, use of validated dietary compliance tool) could not be gauged. In conclusion, very low-level evidence suggests that low-inflammatory diets or supplements compared to usual diets are associated with greater weight loss and improvement in inflammatory biomarkers. More high-quality trials are needed to assess the health effects of a low-inflammatory diet more comprehensively and conclusively in arthritic conditions.

Effects of Protein Supplementation Combined with Exercise Training on Muscle Mass and Function in Older Adults with Lower-Extremity Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Trials

Aging and osteoarthritis (OA) are associated with a high risk of muscle mass loss, which can lead to physical disability. This study investigated the effectiveness of protein supplementation combined with exercise training (PS + ET) in improving muscle mass and functional outcomes in older adults with lower-limb OA. A comprehensive search of online databases was performed to identify randomized controlled trials (RCTs) on the effectiveness of PS + ET in older adults with hip or knee OA. Meta-analysis and risk of bias assessment of the included RCTs were conducted. Six RCTs were included in this systemic review; they had a median (range/total) Physiotherapy Evidence Database (PEDro) score of 7 (6-9) out of 10, respectively. Five RCTs that enrolled patients who underwent total joint replacement were included in this meta-analysis. The PS + ET group exhibited significant improvements in muscle mass (standard mean difference [SMD] = 1.13, p < 0.00001), pain (SMD = 1.36, p < 0.00001), and muscle strength (SMD = 0.44, p = 0.04). Our findings suggest that PS + ET improves muscle mass, muscle strength, and functional outcomes and reduces pain in older adults with lower-limb OA, particularly in those who have undergone total joint replacement.

Distinct Pattern of Inflammation of Articular Cartilage and the Synovium in Early and Late Hip Femoroacetabular Impingement

BACKGROUND

The molecular mechanism of how femoroacetabular impingement (FAI) morphology leads to hip osteoarthritis (OA) is yet to be determined. The expression and location of inflammation-related molecules during early- and late-stage FAI have not been previously described. Moreover, the characterization of intra-articular inflammation away from the cam deformity as well as the nature of adjacent synovial tissue have also not been extensively reported.

HYPOTHESIS

Early-stage FAI has a similar expression of inflammation-related markers in the head-neck and acetabular cartilage but less synovitis than late-stage FAI.

STUDY DESIGN

Controlled laboratory study.

METHODS

Head-neck cartilage, acetabular cartilage, and synovial samples were obtained from patients undergoing hip preservation surgery for the treatment of symptomatic cam FAI (early FAI group; n = 15) and advanced OA secondary to cam FAI (late FAI group; n = 15). Samples procured from healthy young adult donors served as the control group (n = 7). Cartilage degeneration was assessed by histology, and the expression of inflammation-related proteins (interleukin-1 beta [IL-1β], matrix metalloproteinase-13 [MMP-13], a disintegrin and metalloproteinase with thrombospondin motifs-4 [ADAMTS-4], type II collagen [COL2], and aggrecan neoepitope [NITEGE]) was measured by immunostaining. Synovial samples in the early and late FAI groups were examined for synovitis and the expression of IL-1β.

RESULTS

Head-neck cartilage in the early FAI group showed significantly more degeneration than the control group and an increased expression of inflammation-related proteins (IL-1β: 69.7% ± 18.1% vs 20.2% ± 4.9%, respectively; MMP-13: 79.6% ± 12.6% vs 25.3% ± 9.5%; ADAMTS-4: 83.9% ± 12.2% vs 24.3% ± 11.1%; NITEGE: 89.7% ± 7.7% vs 39.8% ± 20.5%) (P < .001). Head-neck and acetabular cartilage in the early and late FAI groups showed a similar degree of degeneration. Moreover, a similar expression of inflammation-related proteins was observed between the early and late FAI groups for head-neck cartilage (IL-1β: 69.7% ± 18.1% vs 72.5% ± 13.2%; MMP-13: 79.6% ± 12.6% vs 71.4% ± 18.8%; ADAMTS-4: 83.9% ± 12.2% vs 82.6% ± 12.5%; COL2: 93.6% ± 3.9% vs 92.5% ± 5.8%; NITEGE: 89.7% ± 7.7% vs 95.7% ± 4.7%) and acetabular cartilage (IL-1β: 83.3% ± 24.8% vs 80.7% ± 15.6%; MMP-13: 94.3% ± 9.7% vs 85.2% ± 12.3%; ADAMTS-4: 98.5% ± 2.3% vs 98.4% ± 3.4%; COL2: 99.8% ± 0.7% vs 99.7% ± 1.1%; NITEGE: 96.7% ± 6.7% vs 99.2% ± 2.2%). In contrast, synovitis was minimal with a low expression of IL-1β in the early FAI group compared with the late FAI group.

CONCLUSION

Hip cartilage exhibited an OA phenotype in patients with early-stage FAI, similar to what was observed in hip OA secondary to FAI. Severe synovitis was only evident with late-stage FAI.

CLINICAL RELEVANCE

This study supports the concept that early hip impingement is associated with cartilage degeneration and catabolism.

Knee Osteoarthritis: A Review of Pathogenesis and State-Of-The-Art Non-Operative Therapeutic Considerations

Being the most common musculoskeletal progressive condition, osteoarthritis is an interesting target for research. It is estimated that the prevalence of knee osteoarthritis (OA) among adults 60 years of age or older is approximately 10% in men and 13% in women, making knee OA one of the leading causes of disability in elderly population. Today, we know that osteoarthritis is not a disease characterized by loss of cartilage due to mechanical loading only, but a condition that affects all of the tissues in the joint, causing detectable changes in tissue architecture, its metabolism and function. All of these changes are mediated by a complex and not yet fully researched interplay of proinflammatory and anti-inflammatory cytokines, chemokines, growth factors and adipokines, all of which can be measured in the serum, synovium and histological samples, potentially serving as biomarkers of disease stage and progression. Another key aspect of disease progression is the epigenome that regulates all the genetic expression through DNA methylation, histone modifications, and mRNA interference. A lot of work has been put into developing non-surgical treatment options to slow down the natural course of osteoarthritis to postpone, or maybe even replace extensive surgeries such as total knee arthroplasty. At the moment, biological treatments such as platelet-rich plasma, bone marrow mesenchymal stem cells and autologous microfragmented adipose tissue containing stromal vascular fraction are ordinarily used. Furthermore, the latter two mentioned cell-based treatment options seem to be the only methods so far that increase the quality of cartilage in osteoarthritis patients. Yet, in the future, gene therapy could potentially become an option for orthopedic patients. In the following review, we summarized all of the latest and most important research in basic sciences, pathogenesis, and non-operative treatment.