Osteoarthritis and the Mediterranean Diet: A Systematic Review

Association of cardiovascular health with morbidity and mortality among U.S. adults with osteoarthritis: a population-based study

BACKGROUND

Osteoarthritis (OA) is recognized as the most common joint disease with serious public health implications. Cardiovascular health (CVH) is also an issue that is frequently emphasized in public health and has an impact on a variety of diseases and mortality rates. This study aims to investigate the association of CVH with the morbidity of OA. And explore the association of CVH with both all-cause and cardiovascular disease (CVD) mortality among US adults with OA.

METHODS

This study utilized data from the National Health and Nutrition Examination Survey 2005-2018, which included 21,289 adults aged ≥ 20, representing 137,912,968 Americans. CVH was assessed by Life's Essential 8 (LE8) includes 4 behavior and 4 factor metrics. Total LE8 scores were calculated from the unweighted average on a 0-100 scale and were categorized as high (80-100), moderate (50-79), and low (0-49) CVH. Multivariable logistic regression explored the association of OA with CVH. Cox proportional hazards regression examined LE8 associations with mortality.

RESULTS

Adjusting for confounding variables, per 10 points LE8 increase, the OR was 0.82 in association with OA, while OA morbidity were decreased by 30% (OR 0.70, 95%CI 0.57, 0.87) and 54% (OR 0.46, 95%CI 0.36, 0.60) in moderate and high CVH compared to low CVH. During a median follow-up of 7.58 years in OA participants, per 10 points LE8 increase were decreased 23% mortality of all-cause (HR 0.77, 95%CI 0.70, 0.85) and 29% mortality of CVD (HR 0.71, 95% 0.60, 0.84). Moderate and high CVH demonstrated a decreased mortality of both all-cause and CVD compared with low CVH.

CONCLUSIONS

Higher CVH is associated with a lower morbidity of OA and lower mortality in OA participants. Our results suggest that adherence to CVH could reduce the morbidity of OA and improve survival outcomes for those affected.

The effectiveness of dietary intervention in osteoarthritis management: a systematic review and meta-analysis of randomized clinical trials

This study aimed to evaluate the impact of various dietary interventions on managing osteoarthritis (OA), a condition significantly affecting global health due to joint alterations driven by inflammatory mediators. A systematic review and meta-analysis, adhering to PRISMA guidelines, examined Randomized Controlled Trials (RCTs) investigating dietary interventions in OA. Two reviewers independently conducted study selection, data extraction, and quality assessment. Random effects models calculated standardized mean differences (SMD) and mean differences (MD). Risk of bias was evaluated with the Cochrane Risk of Bias tool (RoB2), and heterogeneity was assessed using I² values. Nine RCTs (898 participants) were identified, assessing various diets: reduced energy (n = 4), Mediterranean (n = 2), low-fat (n = 2), anti-inflammatory (n = 1), low-carbohydrate (n = 1), and plant-based (n = 1). Dietary interventions significantly improved pain (SMD: -0.67; 95% CI: [-1.01, -0.34]; p < 0.0001), and physical function (SMD: -0.62; 95% CI: [-0.94, -0.30]; p = 0.0001) and body weight (MD: -3.18; 95% CI: [-3.52, -2.83], p < 0.0001). Subgroup analyses revealed reduced energy diets improved pain (SMD: -0.85; 95% CI: [-1.15, -0.55], p < 0.0001), physical function (SMD: -0.95; 95% CI: [-1.33, -0.58], p < 0.0001) and body weight (MD: -3.13; 95% CI: [-3.77, -2.49], p < 0.0001). The Mediterranean diet did not significantly impact pain (SMD: -0.27; 95% CI: [-1.14, 0.60], P = 0.54), or physical function (SMD = -0.28; 95% CI: [-0.79, 0.24], p = 0.29). This study emphasizes the significant impact of dietary interventions on pain, physical function, and weight management in people with OA, with reduced energy diets showing the most effectiveness. Specific dietary patterns show promise but require further investigation.

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

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

Rethinking Osteoarthritis Management: Synergistic Effects of Chronoexercise, Circadian Rhythm, and Chondroprotective Agents

Osteoarthritis (OA) is a chronic and debilitating joint disease characterized by progressive cartilage degeneration for which no definitive cure exists. Conventional management approaches often rely on fragmented and poorly coordinated pharmacological and non-pharmacological interventions that are inconsistently applied throughout the disease course. Persistent controversies regarding the clinical efficacy of chondroprotective agents, frequently highlighted by pharmacovigilance agencies, underscore the need for a structured evidence-based approach. Emerging evidence suggests that synchronizing pharmacotherapy and exercise regimens with circadian biology may optimize therapeutic outcomes by addressing early pathological processes, including low-grade inflammation, oxidative stress, and matrix degradation. Recognizing the influence of the chondrocyte clock on these processes, this study proposes a 'prototype' for a novel framework that leverages the circadian rhythm-aligned administration of traditional chondroprotective agents along with tailored, accessible exercise protocols to mitigate cartilage breakdown and support joint function. In addition, this model-based framework emphasizes the interdependence between cartilage chronobiology and time-of-day-dependent responses to exercise, where strategically timed joint activity enhances nutrient and waste exchange, mitigates mitochondrial dysfunction, supports cellular metabolism, and promotes tissue maintenance, whereas nighttime rest promotes cartilage rehydration and repair. This time-sensitive, comprehensive approach aims to slow OA progression, reduce structural damage, and delay invasive procedures, particularly in weight-bearing joints such as the knee and hip. However, significant challenges remain, including inter-individual variability in circadian rhythms, a lack of reliable biomarkers for pharmacotherapeutic monitoring, and limited clinical evidence supporting chronoexercise protocols. Future large-scale, longitudinal trials are critical to evaluate the efficacy and scalability of this rational integrative strategy, paving the way for a new era in OA management.

Ferroptosis in Osteoarthritis: Towards Novel Therapeutic Strategy

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

Treatment of Osteoporosis and Osteoarthritis in the Oldest Old

Osteoporosis and osteoarthritis are key diseases of musculoskeletal ageing and are increasing in prevalence and burden with the progressively ageing population worldwide. These conditions are thus particularly common in 'the oldest old', and there are complexities of managing them within the context of extensive multimorbidity, physical and mental disability, and polypharmacy, the rates for all of which are high in this population. In this narrative review, we explore the epidemiology of osteoporosis and osteoarthritis in the oldest old before examining trials and real-world data relating to the pharmacological treatment of these diseases in older adults, including anti-resorptives and bone-forming agents in osteoporosis and symptomatic slow-acting drugs for osteoarthritis, paracetamol, and non-steroidal anti-inflammatory drugs in osteoarthritis, recognising that the oldest old are usually excluded from clinical trials. We then review the potential benefits of nutritional interventions and exercise therapy before highlighting the health economic benefits of interventions for osteoporosis and osteoarthritis. The high prevalence of risk factors for both disease and adverse events associated with treatment in the oldest old mean that careful attention must be paid to the potential benefits of intervention (including fracture risk reduction and improvements in osteoarthritis pain and function) versus the potential harms and adverse effects. Further direct evidence relating to such interventions is urgently needed from future research.

The association between dietary fiber intake and osteoarthritis: a cross-sectional study from the 1999-2018 U.S. National Health and Nutrition Examination Survey

OBJECTIVE

The relationship between dietary fiber intake and osteoarthritis (OA) remains unclear. This cross-sectional study, using data from the National Health and Nutrition Examination Survey (NHANES), aimed to examine the association between dietary fiber intake and OA.

METHODS

A cross-sectional analysis was conducted using NHANES data from 1999 to 2018 to assess the association between dietary fiber intake and OA. Univariate and multivariate weighted logistic regression models, along with restricted cubic spline (RCS) curves, were used to evaluate the relationship.

RESULTS

A total of 30,620 participants were included in this study, of whom 1,864 were diagnosed with OA, yielding a prevalence of 5.74%. Multivariate weighted logistic regression revealed a consistent inverse association between dietary fiber intake and OA (OR = 0.99, 95% CI: 0.97-0.99, P = 0.018). When dietary fiber was treated as a categorical variable, the highest quartile of intake (Q4) was associated with a 27% lower risk of OA compared to the lowest quartile (Q1) (OR = 0.73, 95% CI: 0.58-0.92, P = 0.007). The RCS analysis indicated a non-linear association between dietary fiber intake and OA risk (non-linear P = 0.013). The threshold effect interval suggested that dietary fiber intake in the range of 14.4-26.7 g was associated with a reduced risk of OA, while intake above this level did not provide significant additional protection.

CONCLUSION

The findings demonstrate a negative linear association between dietary fiber intake and OA risk. Increasing dietary fiber consumption may reduce the risk of OA, offering potential strategies for its prevention and management. Further studies are needed to confirm these findings.

Association between niacin intake and osteoarthritis in the US population based on NHANES 1999-2018

The relationship between niacin and osteoarthritis (OA) is not clear. Using a retrospective cohort study from the National Health and Nutrition Examination Survey (NHANES), this study aimed to investigate the association between niacin intake and osteoarthritis. This study conducted a cross-sectional analysis using data from the National Health and Nutrition Examination Survey 1999-2018 to investigate the association between niacin intake and osteoarthritis. The association between niacin and osteoarthritis was assessed using univariate and multivariate weighted logistic regression models and restricted cubic spline curves (RCS). Nonlinear correlation is analyzed by fitting smooth curve. In this study, 30,620 participants were examined, with 1,864 individuals diagnosed with osteoarthritis, resulting in a prevalence of 5.74%. Utilizing multivariate weighted logistic regression, a consistent inverse relationship between Niacin and osteoarthritis was observed (OR = 0.99, 95% CI: 0.98-0.99, P = 0.003). When Niacin was treated as a categorical variable, the highest Niacin quartile (Q4) exhibited a 33% reduced risk of osteoarthritis compared to the lowest quartile (Q1) (OR = 0.67, 95% CI: 0.53-0.83, P = 0.0004). The restricted cubic spline analysis revealed a non-linear association between Niacin and osteoarthritis risk (non-linear P = 0.022), with 33.53 as the inflection point. Subgroup analyses further highlighted a stronger inverse relationship between Niacin and osteoarthritis in Non - Hispanic Black and other Race patients. The results showed a negative linear relationship between niacin intake and OA risk. By increasing the intake of niacin-rich foods, the risk of osteoarthritis can be reduced, providing ideas for the prevention and treatment of osteoarthritis. Further future studies are recommended to validate our findings.

Polyunsaturated fatty acids may not be helpful for people with osteoarthritis: a two-sample Mendelian randomization analysis

In recent years, researchers have examined the use of polyunsaturated fatty acids (PUFA) or a low omega-6/3 ratio to protect the knee joint. The current study is based on genome-wide association study (GWAS) analysis and uses the Mendelian randomization (MR) method to evaluate the effect of total PUFA, omega-3, omega-6, and omega-6/3 ratios on osteoarthritis (OA). First, we downloaded the latest PUFA and OA GWAS data. The PUFA data were divided into four groups: total PUFA, omega-3, omega-6, and omega-6/3 ratios. The OA data were split into nine groups: hip OA (total, males, and females), knee OA (total, males, and females), and hand OA (total, males, and females). Then, qualified SNPs were selected as instrumental variables. Inverse variance weighting (IVW), weighted median, and the MR‒Egger method were used for MR analysis. Finally, MR‒Egger, MR-Presso, and Cochran's Q statistical methods were used to evaluate the heterogeneity and pleiotropy. Thirty-six IVW results showed that total PUFA, omega-3, omega-6, and omega-6/3 ratios did not significantly increase or decrease the risk of knee, hip, and hand OA. The IVW results of the effect of PUFA on OA (male and female) were as follows: total PUFA-knee OA (OR: 0.97, 95% CI: 0.92-1.02, P = 0.283); total PUFA-hip OA (OR: 1.01, 95% CI: 0.93-1.08, P = 0.806); total PUFA-hand OA (OR: 0.99, 95% CI: 0.91-1.07, P = 0.896). There was no obvious horizontal polytropy in all the analyses, and there was heterogeneity in some analyses. Our study does not indicate that total PUFA, mega-3, and low omega-6/3 ratios are helpful for people with OA, nor does it indicate that omega-6 increases the risk of OA. The dietary management of PUFA in OA patients needs to be performed cautiously.

Associations between nutrient intake and osteoarthritis based on NHANES 1999 to 2018 cross sectional study

The relationship between nutrient intake and osteoarthritis (OA) remains unclear. This study utilized data from the National Health and Nutrition Examination Survey (NHANES) in a multi-cycle retrospective cohort study to explore the associations between the intake of six nutrients-carbohydrates, dietary fiber, protein, fat, folate, niacin and OA. This study performed a cross-sectional analysis using NHANES data from 1999 to 2018 to investigate the relationship between the intake of six nutrients and OA. Univariate and multivariate weighted logistic regression models, along with restricted cubic splines (RCS), were applied to assess the associations between nutrient intake and OA. A total of 32,484 participants were included in the study, of whom 1864 were diagnosed with OA, resulting in a prevalence rate of 5.74%. Multivariate weighted logistic regression consistently demonstrated that dietary fiber, folic acid, and nicotinic acid intake were negatively associated with the presence of OA, while protein intake exhibited a J-shaped relationship with OA, and carbohydrate or fat intake showed no significant association with OA. Compared with participants in the lowest quartile (Q1), those in the highest quartile (Q4) of dietary fiber, folic acid, and nicotinic acid intake had 27%, 28%, and 33% lower odds of having OA, respectively, after adjusting for potential confounding factors. RCS analysis revealed that dietary fiber and nicotinic acid intake had a nonlinear relationship with the presence of OA, folic acid intake had a linear relationship with OA, and protein intake followed a J-shaped curve with OA. These results suggest that higher intake of dietary fiber, folic acid, and nicotinic acid is associated with a reduced likelihood of OA, while protein intake follows a J-shaped curve, with moderate intake offering the greatest protection. These findings highlight the importance of balancing protein intake and optimizing the consumption of other nutrients for the prevention and management of OA. Further research is needed to confirm these findings and clarify the underlying mechanisms.

The climate emergency for rheumatologists: where do we stand?

Climate change and pollution are a major existential threat. Healthcare contributes a noteworthy 4-6% to the total carbon footprint and 5-7% of the total greenhouse gas (GHG) emissions. Environmental pollution and modern lifestyles are also contributing to the increased prevalence of autoimmune and lifestyle-related rheumatic disease. In this review, we assess both the effects of rheumatological practice on climate change and the potential impact of climate change on rheumatological diseases. Preliminary evidence suggests that climate change is linked with the inception or exacerbation of some of the autoimmune and inflammatory rheumatic diseases (AIRDs) like rheumatoid arthritis, lupus, systemic sclerosis, and reactive arthritis. Furthermore, with rampant industrialization and pollution, emerging infections such as Dengue, Zika virus, and chikungunya have emerged as triggers of inflammatory arthritis. Strategies at different levels are proposed to mitigate the effect of the healthcare industry and the community on the environment. The rheumatology community can acknowledge and begin to address the challenges of climate change and health.

Ketogenic Diet-Associated Worsening of Osteoarthritis Histologic Secerity, Increased Pain Sensitivity and Gut Microbiome Dysbiosis in Mice

OBJECTIVES

Dietary interventions are a potentially powerful treatment option for knee osteoarthritis (OA). The objective of this study was to evaluate a well-formulated ketogenic diet (KD) in the context of knee OA histology and pain using the destabilization of the medial meniscus (DMM) mouse model and correlate with gut microbiome and systemic cytokine levels.

METHODS

Adult male mice underwent unilateral DMM or sham surgery and were then fed eight weeks of KD or chow. At baseline and every two weeks, mechanical allodynia of the operated and contralateral knees was assessed via analgesiometry. Knee joints were collected for histology, gut microbiome analysis was performed on cecal material via 16S sequencing, and serum cytokines were analyzed via Bio-Plex assay.

RESULTS

KD mice had worse histopathologic OA after DMM (mean ± SEM Osteoarthritis Research Society International score: KD-DMM: 4.0 ± 0.5 vs chow-DMM: 2.7 ± 0.08; P = 0.02). KD mice had increased mechanical allodynia postsurgery (P = 0.005 in mixed-effects model). The gut microbiome changed substantially with KD: 59 clades were altered by KD in DMM and 39 by KD in sham (36 were shared, 25 overlapped with previous murine OA studies). Several clades were correlated on an individual-mouse level with both histology and allodynia (eg, Lactobacillus histology P = 0.004, allodynia P = 1 × 10-4). Serum analysis showed four cytokines increased with KD (interleukin [IL]-1β, IL-2, IL-3, and IL-13).

CONCLUSION

KD started immediately after OA induction via DMM is associated with worsened histologic outcomes. KD also worsens mechanical allodynia after either DMM or sham surgery. KD induces significant gut microbiome dysbiosis in clades previously associated with murine OA.

Arctiin alleviates knee osteoarthritis by suppressing chondrocyte oxidative stress induced by accumulated iron via AKT/NRF2/HO-1 signaling pathway

Iron overload (IO) was considered to be a risk factor for cartilage degradation in knee osteoarthritis (KOA) advancement. However, few drugs were found to improve cartilage degeneration by alleviating multiple cell death induced by the impaired iron level of the knee joints. We aimed to elucidate that Arctiin (ARC) plays a role in managing KOA caused by accumulated iron levels by restoring chondrocyte apoptosis and ferroptosis. Single-cell RNA sequencing analysis was used to discover the disparities in chondrocytes between KOA patients and non-KOA individuals. CCK-8 assay was performed to detect chondrocyte viability. Annexin V-FITC/PI staining determined the cell apoptosis rate. The fluorescence density reflected the iron content, ROS, lipid-ROS, and mitochondrial membrane potential. Q-RTPCR and Western Blotting were used to detect the expression levels of genes and proteins expression. Micro-CT and Safranin O-Fast Green staining were used to detect the phenotype of the knee joints. ARC increased cell viability and inhibited chondrocyte apoptosis. Further, ARC acts as an anti-ferroptosis effect by reducing the intracellular iron, ROS, and lipid-ROS content and restoring mitochondrial damage. Based on the results of scRNA-seq, we found that ARC can play a role by activating AKT/NRF2/HO-1 signaling pathway. In vivo, ARC can significantly improve the severity of KOA caused by IO. ARC alleviates oxidative stress in chondrocytes via the AKT/NRF2/HO-1 signaling pathway, suggesting the potential application of ARC in KOA.

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

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

Mediterranean diet and osteoarthritis: an update

The Mediterranean diet has gained significant attention for its potential health benefits on diverse pathological conditions including osteoarthritis (OA), a prevalent degenerative joint disease characterized by cartilage breakdown and inflammation. Numerous observational studies have suggested that adherence to the Mediterranean diet, may have protective effects against OA. The abundance of antioxidants and anti-inflammatory compounds and omega-3 fatty acids, among the Mediterranean diet components is believed to contribute to its beneficial effects on OA. Research investigating the association between the Mediterranean diet and OA has shown promising results. Several observational studies have reported that adherence to the Mediterranean diet is associated with a reduced risk of developing OA and with lower severity of OA symptoms. Additionally, intervention studies have demonstrated improvements in pain, function, and quality of life among OA patients following a Mediterranean diet intervention. Furthermore, emerging evidence suggests potential mechanisms underlying the protective effects of the Mediterranean diet against OA, including its ability to reduce inflammation, oxidative stress, and cartilage degradation. However, further well-designed randomized controlled trials and mechanistic studies are needed to elucidate the precise mechanisms and establish causality. In conclusion, the Mediterranean diet appears to be a promising dietary approach for the prevention and management of OA. Its rich array of nutrients and bioactive compounds may exert protective effects against OA development and progression, although more research is warranted to confirm these findings and elucidate underlying mechanisms.

Acupotomy therapy for knee osteoarthritis: An overview of systematic reviews

BACKGROUND

This study aimed to evaluate the methodological quality, report quality, and evidence quality of a meta-analysis (MA) and systematic review (SR) of the efficacy of acupotomy in the treatment of knee osteoarthritis (KOA), and provided a reference for clinical decision-making.

METHODS

We searched 8 databases to collect systematic reviews and meta-analyses on the efficacy of acupotomy in the treatment of KOA from January 30, 2018, to January 31, 2023. The methodological quality of the studies was assessed using the assessment of multiple systematic reviews (AMSTAR) 2 scale, the quality of the literature reports was scored using the Preferred Reporting Items for Systems Reviews and Meta-Analyses 2020 Version (PRISMA 2020),and the quality of the evidence was graded using the grading of recommendations assessment, development, and evaluation (GRADE) scale.

RESULTS

Nine systematic reviews including 35 outcome indicators were included. AMSTAR 2 evaluated the methodological quality of the included studies, and 1 was of low quality, 8 were of very low quality, and the entries with poor scores were 2, 3, 4, 8, 10, 12, and 13. By PRISMA 2020, there were some reporting deficiencies, and quality problems were mainly reflected in the abstract, information sources, search strategy, synthesis methods, reporting bias assessment, certainty assessment, reporting biases, certainly of evidence, registration and protocol. The GRADE classification results showed that there were 2 medium-quality evidences, 7 low-quality evidences, and 26 very low-quality evidences. The main factors of degradation were limitations, imprecision, and publication bias.

CONCLUSION

Acupotomy had been a promising complementary treatment for KOA. However, due to the low quality of the SRs/MAs supporting these results, high-quality studies with rigorous study designs and larger samples were needed before widespread recommendations could be made.

Microbiome-Augmented Model for Predicting Knee Osteoarthritis Progression Based on Gut Microbiota and Kellgren-Lawrence Classification

PURPOSE

 Knee osteoarthritis (OA) is a widespread chronic degenerative condition that may experience slow or rapid deterioration. The gut-joint axis represents a bidirectional relationship in OA onset and progression. This study aimed to establish and validate a prediction model of knee OA disease progression.

METHODS

This prospective cohort investigation involved 296 patients diagnosed with knee OA using X-ray and CT scans at Taizhou People's Hospital from January 2020 to January 2022. Fecal samples and general information were collected for gut microbiota analysis. Least absolute shrinkage and selection operator (LASSO) regression and various prediction models, including microbiome-augmented models, were employed for knee OA risk prediction. The models predicting Kellgren-Lawrence classification one year later were evaluated by accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC).

RESULTS

A total of 270 patients were involved in our study. After random assignment, 214 patients belonged to the training set and 56 patients belonged to the test set. The final intestinal flora included in the analysis included the following 12 species. Shannon index of patients with a Grade I Kellgren-Lawrence Classification after one year was lower than those with a Grade II/III after one year (P=0.018). The best model was the microbiome-augmented model built by Light GBM (LGBM). The AUC of this model in the training set was 0.812 (0.754-0.870), the sensitivity was 0.804 (0.725-0.883), the specificity was 0.744 (0.664-0.823), the PPV was 0.722 (0.638-0.807), the NPV was 0.821 (0.748-0.894), and the accuracy was 0.771 (0.715-0.827). The AUC of this model in the testing set was 0.876 (0.781-0.972), the sensitivity was 0.759 (0.603-0.914), the specificity was 0.917 (0.806-1.000), the PPV was 0.917 (0.806-1.000), the NPV was 0.759 (0.603-0.914), and the accuracy was 0.830 (0.729-0.931).  Conclusion: One year later, the microbiome-augmented model constructed by LGBM for knee OA patients based on general and gut microbiota data using the Kellgren-Lawrence classification demonstrated the highest performance. This approach could aid in identifying patients at risk of rapid disease progression, facilitating early intervention and personalized treatments. Furthermore, it offers a novel perspective on the gut-joint axis's role in OA.

Better diet quality is associated with reduced body pain in adults regardless of adiposity: Findings from the Whyalla Intergenerational Study of Health

Dietary intake has been associated with pain and physical function, but it is unclear if these relationships are mediated by adiposity. Data were derived from the Whyalla Intergenerational Study of Health (n = 654, 57% women). Structural equation modelling tested the hypotheses that adiposity (body mass index (BMI), waist circumference (WC), or body fat (BF, dual energy x-ray absorptiometry)) would mediate the relationship between diet quality (Dietary Guideline Index (DGI) total, core, or non-core scores) and pain (Short Form-36 bodily pain scale (SF36-BPS)), or physical function (grip-strength), overall, and by gender. Adiposity did not mediate a relationship between DGI scores and pain. Direct effects were observed between DGI total scores and SF36-BPS accounting for BMI (β = 0.170, 95% CI 0.002, 0.339), and between DGI core food scores and SF36-BPS (BMI, β = 0.278, 95% CI 0.070, 0.486; WC, β = 0.266, 95% CI 0.058, 0.474; BF, β = 0.266, 95% CI 0.060, 0.473). In women, direct effects existed between DGI scores and SF36-BPS (DGI total scores, BMI, β = 0.388, 95% CI 0.162, 0.613; WC, β = 0.372, 95% CI 0.146, 0.598; BF, β = 0.382, 95% CI 0.158, 0.605, and DGI core scores, BMI, β = 0.482, 95% CI 0.208, 0.757; WC, β = 0.472, 95% CI 0.197, 0.747; BF, β = 0.467, 95% CI 0.195, 0.739), and DGI total scores and grip-strength (BMI, β = 0.075, 95% CI 0.008, 0.142; WC, β = 0.076, 95% CI 0.009, 0.143; BF, β = 0.079, 95% CI 0.011, 0.146). Better diet quality is associated with lower bodily pain, irrespective of adiposity. Findings highlight the potential role of diet quality in pain management and function, particularly in women.

Adherence to the Mediterranean Diet: A Tool to the Therapeutic Approaches for Patients With Temporomandibular Joint Disorders

BACKGROUND AND AIM

Temporomandibular joint disorder (TMD) is characterized by symptoms such as clenching, clicking, and locking of the jaw, often due to improper positioning affecting occlusion. Nearly half of TMD patients rarely require treatment, as symptoms typically diminish on their own within a year. Nevertheless, a significant majority of persons who are diagnosed with TMD do necessitate therapy, and it may take up to three years for complete remission to occur. This study aims to determine the extent to which a healthy nutritional model, specifically the Mediterranean diet, can enhance the effectiveness of existing therapeutic treatments, like physiotherapy with warm pads.

METHODS

An interventional study design was implemented. Baseline scores were obtained pre- and post-intervention, while Mediterranean diet adherence was evaluated once at the beginning. A dependent samples t-test and a one-way multivariate analysis of covariance (MANCOVA) were used to test the experimental hypotheses.

RESULTS

There is a statistically significant difference (p=0.04) between the three groups associated with Mediterranean diet adherence, as indicated by the mean differences on the Jaw Functional Limitation Scale (JFLS-20) questionnaire. Participants following a medium or high level of Mediterranean diet (≥18) reported fewer problems with jaw functionality both before and after the intervention compared to those with low (<18) adherence to the diet.

CONCLUSION

Adherence to the Mediterranean diet appears to have a therapeutic effect on patients with TMD, offering a new dimension to their treatment. The primary benefit is the low cost of treatment, as the diet is easily accessible. This dietary approach could significantly enhance the management of TMD symptoms.

Effects of Fasting on THP1 Macrophage Metabolism and Inflammatory Profile

Fasting can affect the body's inflammatory response, and this has been linked to potential health benefits, including improvements for people with rheumatic diseases. In this work, we evaluated, in vitro, how changes in nutrient availability alter the inflammatory response of macrophages. Macrophage-differentiated THP1 cells were cultured, deprived of FCS or subjected to cycles of FCS deprivation and restoration to mimic intermittent fasting. Changes in the macrophage phenotype, the cells' response to inflammatory stimuli and the level of mitochondrial alteration were assessed. The results indicate that while periods of serum starvation are associated with a decrease in IL1β and TNFα expression, consistent with an anti-inflammatory response, intermittent serum starvation cycles promote a pro-inflammatory phenotype. Rapid changes in reducing capacity and mitochondrial response were also observed. Of note, while some changes, such as the production of oxygen free radicals, were reversed with refeeding, others, such as a decrease in reducing capacity, were maintained and even increased. This study shows that different fasting protocols can have diverging effects and highlights that time-limited nutrient changes can significantly affect macrophage functions in cell cultures. These findings help elucidate some of the mechanisms by which specific fasting dietary interventions could help control inflammatory diseases.

Ankle Osteoarthritis

Ankle osteoarthritis (OA) is less common than knee and hip OA, and 75% to 80% of all presentations are posttraumatic in nature, resulting from either ligamentous or bony injury to the ankle. While the ankle joint cartilage demonstrates capacity for self-restoration, the ankle joint is sensitive to aberrancies in biomechanics and the inflammatory milieu after an injury is thought to contribute to the onset of posttraumatic ankle OA. Conservative care for ankle OA is currently centered on pain reduction, and derivatives that may delay the progression of ankle OA are the subject of ongoing investigation. Surgical management for end-stage ankle OA currently focuses on ankle arthrodesis and total ankle arthroplasty. Specific indication for one procedure over the other is the topic of much debate. While total ankle arthroplasty has become more frequently used with the advent of newer generation systems, ankle arthrodesis may still be favored in younger patients with high-demand occupations.

METTL14 promotes chondrocyte ferroptosis in osteoarthritis via m6A modification of GPX4

BACKGROUND

Ferroptosis is caused by iron-dependent peroxidation of membrane phospholipids and chondrocyte ferroptosis contributes to osteoarthritis (OA) progression. Glutathione peroxidase 4 (GPX4) plays a master role in blocking ferroptosis. N6-methyladenosine (m6A) is an epigenetic modification among mRNA post-transcriptional modifications. This study investigated the effect of methyltransferase-like 14 (METTL14), the key component of the m6A methyltransferase, on chondrocyte ferroptosis via m6A modification.

METHODS

An OA rat model was established through an intra-articular injection of monosodium iodoacetate in the right knee. OA cartilages in rat models were used for gene expression analysis. Primary mouse chondrocytes or ADTC5 cells were stimulated with IL-1β or erastin. The m6A RNA methylation quantification kit was used to measure m6A level. The effect of METTL14 and GPX4 on ECM degradation and ferroptosis was investigated through western blotting, fluorescence immunostaining, propidium iodide staining, and commercially available kits. The mechanism of METTL14 action was explored through MeRIP-qPCR assays.

RESULTS

METTL14 and m6A expression was upregulated in osteoarthritic cartilages and IL-1β-induced chondrocytes. METTL14 depletion repressed the IL-1β or erastin-stimulated ECM degradation and ferroptosis in mouse chondrocytes. METTL14 inhibited GPX4 gene through m6A methylation modification. GPX4 knockdown reversed the si-METTL14-mediated protection in IL-1β-induced chondrocytes.

CONCLUSION

METTL14 depletion inhibits ferroptosis and ECM degradation by suppressing GPX4 mRNA m6A modification in injured chondrocytes.

Diet modification reduces pain and improves function in adults with osteoarthritis: a systematic review

BACKGROUND

The effect of dietary modifications on pain and joint function in adults with osteoarthritis (OA) is an emerging area of study. This systematic review aimed to evaluate if adults with OA who consume diets with a higher proportion of plant phenols and omega-3 fatty acids would have less pain and improved joint function than those with a higher proportion of saturated fatty acids, omega-6 fatty acids and refined carbohydrates.

METHODS

Database searches of CINAHL (EBSCO), Clinical Trials (NIH-NLM), Cochrane Library (Wiley), Dissertation & Thesis Global (ProQuest), Embase (Elsevier), Medline (OVID), PubMed (NLM), Scopus (Elsevier), Web of Sciences (Clarivate) for clinical trials identified 7763 articles published between January 2015 and May 2023. After an independent review of the articles, seven randomised clinical trials and one nonrandomised clinical trial were included in the analysis. Because of the heterogeneity of the outcome measures, a meta-analysis was not possible.

RESULTS

Participants who were instructed to consume high-phenol/high-omega-3 fatty acid diets reported significant improvements in pain and physical function scores. The greatest improvement was reported by those who consumed a diet that had the most omega-3 fatty acids.

CONCLUSION

Because of the high risk of bias, the strength of the evidence is limited. However, there is evidence that counselling adults with OA to replace refined grains and processed foods with whole plant foods, fish and plant oils may have a favourable effect on pain and physical function. Routine follow-up care regarding these diet modifications may be necessary to ensure adherence to this therapy.

The Effectiveness of a Single Hyaluronic Acid Injection in Improving Symptoms and Muscular Strength in Patients with Knee Osteoarthritis: A Multicenter, Retrospective Study

Knee osteoarthritis (KOA) is a progressive and multifactorial disease that leads to joint pain, muscle weakness, physical disability, and decreased quality of life. In KOA, the quantity of hyaluronic acid (HA) and the molecular weight (MW) are decreased, leading to joint pain due to increased wear of the knee articular cartilage. Arthrogenic muscle inhibition, which is usually found in patients with KOA, is associated with joint inflammation, pain, and swelling, also causing muscle atrophy, primarily of the anterior thigh muscles, and hindering the rehabilitation process. The aim of our work was to determine if a single HA infiltration could minimize the effects of arthrogenic muscle inhibition in patients with KOA in the short term, using isokinetic dynamometry to evaluate the strength of the knee extensor and flexor muscles of the thigh. Thirty patients with KOA who underwent both clinical and isokinetic assessment, and that received a single injection of HA, were retrospectively included. Our results showed that a single intra-articular injection of HA significantly reduces pain and improves joint function at four weeks, while non-statistically significant improvements were observed for the reference isokinetic parameter (maximum torque) at both 90°/s and 180°/s. Further high-quality studies are necessary to confirm the results of our study.

Effects of Pomegranate (Punica granatum L.) Peel Extract Supplementation on Markers of Inflammation and Serum Matrix Metalloproteinase 1 in Women With Knee Osteoarthritis: A Randomized Double-Blind Placebo-Controlled Study

Objective

Osteoarthritis (OA) as a common musculoskeletal disorder is the main cause of disability in the world. The present study aimed to evaluate the effects of pomegranate peel extract (PPE) on some inflammatory markers and matrix maloproteinase1 (MMP1) in women with knee OA.

Methods

Sixty obese women with knee OA aged 38 to 60 years were included in this clinical trial. The women were allocated into intervention (n = 30) and placebo (n = 30) groups along with standard drug therapy receiving 500 mg PPE or placebo twice daily for 8 weeks, respectively. Three-day food records, anthropometric measurements, fasting blood samples, and physical activity questionnaires were gathered at the baseline and the end of the study.

Results

The supplementation of PPE significantly reduced the serum high-sensitivity C-reactive protein (hs-CRP), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB), MMP1, and monocyte chemoattractant protein-1 (MCP-1) levels of the patients within the intervened group (all, P < .05) and compared with the placebo (P = .002, .045, .040, and .003, respectively) at the end of the study. The serum NF-ĸB levels significantly increased within the placebo group at the end of the trial (P = .002). Changes in other variables in the placebo group were not significant (P > .05).

Conclusions

The findings of this clinical trial indicated that PPE supplementation decreased serum inflammatory markers including hs-CRP, NF-ĸB, and MCP-1 and MMP1 levels in women with knee OA. PPE supplementation may be useful as a part of an integrated approach to modulating inflammatory complications in women with knee OA.

The metabolic characteristics and changes of chondrocytes in vivo and in vitro in osteoarthritis

Osteoarthritis (OA) is an intricate pathological condition that primarily affects the entire synovial joint, especially the hip, hand, and knee joints. This results in inflammation in the synovium and osteochondral injuries, ultimately causing functional limitations and joint dysfunction. The key mechanism responsible for maintaining articular cartilage function is chondrocyte metabolism, which involves energy generation through glycolysis, oxidative phosphorylation, and other metabolic pathways. Some studies have shown that chondrocytes in OA exhibit increased glycolytic activity, leading to elevated lactate production and decreased cartilage matrix synthesis. In OA cartilage, chondrocytes display alterations in mitochondrial activity, such as decreased ATP generation and increased oxidative stress, which can contribute to cartilage deterioration. Chondrocyte metabolism also involves anabolic processes for extracellular matrix substrate production and energy generation. During OA, chondrocytes undergo considerable metabolic changes in different aspects, leading to articular cartilage homeostasis deterioration. Numerous studies have been carried out to provide tangible therapies for OA by using various models in vivo and in vitro targeting chondrocyte metabolism, although there are still certain limitations. With growing evidence indicating the essential role of chondrocyte metabolism in disease etiology, this literature review explores the metabolic characteristics and changes of chondrocytes in the presence of OA, both in vivo and in vitro. To provide insight into the complex metabolic reprogramming crucial in chondrocytes during OA progression, we investigate the dynamic interaction between metabolic pathways, such as glycolysis, lipid metabolism, and mitochondrial function. In addition, this review highlights prospective future research directions for novel approaches to diagnosis and treatment. Adopting a multifaceted strategy, our review aims to offer a comprehensive understanding of the metabolic intricacies within chondrocytes in OA, with the ultimate goal of identifying therapeutic targets capable of modulating chondrocyte metabolism for the treatment of OA.

Association between the dietary inflammatory index and all-cause mortality in osteoarthritis

BACKGROUND

To investigate the association between the Dietary Inflammatory Index (DII) and all-cause mortality in patients with osteoarthritis (OA).

METHODS

In this retrospective cohort study, data on OA patients were obtained from the National Health and Nutrition Examination Survey (NHANES) 2003-2018. OA diagnosis was self-reported. The study population was divided into low and high DII groups based on the DII's median. All-cause mortality was the outcome, which was determined via linkage to the National Death Index (NDI) until 31 December 2019. Multivariable Cox regression analyses were employed to investigate the association between the DII and all-cause mortality. The survival of the low and high DII groups was exhibited by Kaplan-Meier curves. Furthermore, subgroup analyses were carried out in terms of age and comorbidity.

RESULTS

A total of 3804 patients with OA were included, with 1902 (50%) in the low DII group and 1902 (50%) in the high DII group. Patients with a high DII had a significantly greater risk of all-cause mortality than those with a low DII (HR = 1.21, 95%CI: 1.02-1.44, P = 0.025). A high DII was associated with a significantly increased risk of all-cause mortality compared with a low DII in patients aged ≥ 65 years [hazard ratio (HR) = 1.28, 95% confidence level (CI): 1.07-1.53, P = 0.006). Hypertensive patients with a high DII had a significantly greater risk of all-cause mortality than those with a low DII (HR = 1.25, 95%CI: 1.03-1.52, P = 0.025). For patients with cardiovascular disease (CVD), a high DII was associated with a significantly higher risk of all-cause mortality than a low DII (HR = 1.43, 95%CI: 1.17-1.75, P < 0.001). A high DII was associated with a significantly greater risk of all-cause mortality, as compared with a low DII in patients with chronic kidney disease (CKD) (HR = 1.22, 95%CI: 1.02-1.45, P = 0.026).

CONCLUSION

The DII was positively associated with the risk of all-cause mortality in patients with OA. This association differed by age, hypertension, CVD, and CKD. Adherence to diet with a low DII may be beneficial in prognosis improvement.

IL21 inhibits miR-361-5p to promote MAP3K9 and further aggravate the progression of shoulder arthritis

OBJECTIVE

This research aimed to explore IL-21/miR-361-5p/MAP3K9 expression in shoulder arthritis and identify its regulatory pathways.

METHODS

We established a rat shoulder arthritis model, then quantified IL21 and miR-361-5p in synovial fluid using ELISA and monitored the arthritis development. Additionally, IL21's effect on miR-361-5p levels in cultured human chondrocytes (HC-a) was assessed. Chondrocyte cell cycle status and apoptosis were measured via flow cytometry. Interactions between miR-361-5p and MAP3K9 were confirmed through dual-luciferase reporting and bioinformatic scrutiny. Protein levels of MAP3K9, p-ERK1/2, p-NF-κB, MMP1, and MMP9 were analyzed by Western blots.

RESULTS

IL21 levels were elevated, while miR-361-5p was reduced in the synovial fluid from arthritic rats compared to healthy rats. IL21 was shown to suppress miR-361-5p in chondrocytes leading to hindered cell proliferation and increased apoptosis. Western blots indicated that miR-361-5p curbed MAP3K9 expression, reducing MMP activity by attenuating the ERK1/2/NF-κB pathway in chondrocytes.

CONCLUSION

IL21 upregulation and miR-361-5p downregulation characterize shoulder arthritis, resulting in MAP3K9 overexpression. This chain of molecular events boosts MMP expression in chondrocytes and exacerbates the condition's progression.

The role of dietary preferences in osteoarthritis: a Mendelian randomization study using genome-wide association analysis data from the UK Biobank

Background

To understand the impact of individual preferences for specific dietary items on OA, and to help inform the development of effective and targeted OA prevention and management strategies, we performed a Mendelian randomization analysis between dietary preferences and osteoarthritis.

Methods

This study utilized genetic data from the UK Biobank to investigate the association between OA and 21 different common dietary items. Instrumental variables representing European populations were carefully selected based on their genetic significance and linkage disequilibrium. In cases where a dietary item had few relevant genetic markers, a more lenient selection threshold was applied. To prevent bias, the analysis excluded single nucleotide polymorphisms (SNPs) associated with factors such as body mass index (BMI) and cholesterol. Using inverse-variance weighting (IVW) and Mendelian randomization, significant associations were detected between certain dietary items and OA.

Results

Using Mendelian randomization to examine the relationship between 21 different dietary items and OA, significant associations were found for coffee, peas, watercress, and cheese, where the first two had a promoting effect and the last two an inhibiting effect on OA. Due to heterogeneity in the test results for cheese, a random IVW representation was used. The results of sensitivity analysis showed no significant heterogeneity or horizontal pleiotropy in the selected SNPS, demonstrating the reliability of Mendelian randomization analysis.

Conclusion

This study identified coffee, peas, watercress, and cheese as food items that may have significant dietary effects on osteoarthritis. This information may be useful to consider in the development of OA management strategies.

Causal association between dried fruit intake and risk of osteoarthritis: A Mendelian randomization study

This study aimed to examine whether dried fruit intake is causally associated with Osteoarthritis (OA). A two-sample Mendelian randomization (MR) analysis using the inverse-variance weighted (IVW), weighted median (WM), and MR-Egger regression methods was performed. We used the publicly available summary statistics data sets of genome-wide association studies (GWAS) meta-analyses for dried fruit intake in individuals included in the UK Biobank (n = 421,764; MRC-IEU consortium) as the exposure and a GWAS publicly available in PubMed for OA (total n = 484,598; case = 39,515, control = 445,083) as the outcome. We selected 41 single nucleotide polymorphisms at genome-wide significance from GWASs on dried fruit intake as the instrumental variables. The IVW method showed evidence to support a causal association between dried fruit intake and OA (beta = -0.020, SE = 0.009, P = .039). MR-Egger regression indicated no directional pleiotropy (intercept = 1E-05; P = .984), but it showed no causal association between dried fruit intake and OA (beta = -0.020, SE = 0.043, P = .610). However, the WM approach yielded evidence of a causal association between dried fruit intake and OA (beta = -0.026, SE = 0.012, P = .026). Cochran's Q test showed the existence of heterogeneity, but the statistics of I2 showed low heterogeneity. The results of MR analysis support that dried fruit intake may be causally associated with a decreased risk of OA.

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

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

Synovia tissue-specific exosomes participate in the dual variation of the osteoarthritis microenvironment via miR-182

Osteoarthritis (OA) is the most common type of joint disease and the leading cause of chronic disability among older adults. As an important component of the joint, synovium influences the inflammatory and degenerative process of OA. This study found that miRNA 182 (miR-182) in synovium-specific exosomes can modulate inflammation and apoptotic signaling. It also regulated different biological functions to promote the progression of OA. Experiments based on rat OA model and synovium samples from OA patients, we found that synovium-derived miR-182 regulates inflammatory response in the early stage of OA by regulating the expression level of forkhead box O-3 (FOXO3). However, the expression of miR-182 was significantly increased in synovial tissue of advanced OA, which was involved in the apoptotic signal of severe OA. These findings suggest that miR-182 may directly regulate OA progression by modulating FOXO3 production inflammation, and apoptosis.

Mechanical Stress Induces Sodium Entry and Osmoprotective Responses in Murine Synovial Fibroblasts

Osteoarthritis (OA) is a multifactorial disease depending on molecular, genetic, and environmental factors like mechanical strain. Next to the cartilage and the subchondral bone, OA also affects the synovium, which is critically involved in the maintenance of joint homeostasis. As there is a correlation between the extracellular sodium content in the knee joint and OA, this study investigates the impact of sodium on OA-associated processes like inflammation and bone remodeling without and with mechanical loading in synovial fibroblasts. For that purpose, murine synovial fibroblasts from the knee joint were exposed to three different extracellular sodium chloride concentrations (-20 mM, ±0 mM and +50 mM NaCl) in the absence or presence of compressive or intermittent tensile strain. In addition to the intracellular Na+ content and gene expression of the osmoprotective transcription factor nuclear factor of activated T cells 5 (Nfat5), the gene and protein expression of inflammatory mediators (interleukin-6 (IL6), prostaglandin endoperoxide synthase-2 (Ptgs2)/prostaglandin E2 (PGE2)), and factors involved in bone metabolism (receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG)) were analyzed by qPCR and ELISA. Mechanical strain already increased intracellular Na+ and Nfat5 gene expression at standard salt conditions to levels obtained by exposure to increased extracellular Na+ content. Both high salt and compressive strain resulted in elevated IL6 and PGE2 release. Intermittent tensile strain did not increase Il6 mRNA expression or IL6 protein secretion but triggered Ptgs2 expression and PGE2 production. Increased extracellular Na+ levels and compressive strain increased RANKL expression. In contrast, intermittent tension suppressed RANKL expression without this response being subject to modification by extracellular sodium availability. OPG expression was only induced by compressive strain. Changes in extracellular Na+ levels modified the inflammatory response and altered the expression of mediators involved in bone metabolism in cells exposed to mechanical strain. These findings indicate that Na+ balance and Nfat5 are important players in synovial fibroblast responses to mechanical stress. The integration of Na+ and Na+-dependent signaling will help to improve the understanding of the pathogenesis of osteoarthritis and could lead to the establishment of new therapeutic targets.

Inhibition of SAT1 alleviates chondrocyte inflammation and ferroptosis by repressing ALOX15 expression and activating the Nrf2 pathway

Aims

Osteoarthritis (OA) is the most common chronic pathema of human joints. The pathogenesis is complex, involving physiological and mechanical factors. In previous studies, we found that ferroptosis is intimately related to OA, while the role of Sat1 in chondrocyte ferroptosis and OA, as well as the underlying mechanism, remains unclear.

Methods

In this study, interleukin-1β (IL-1β) was used to simulate inflammation and Erastin was used to simulate ferroptosis in vitro. We used small interfering RNA (siRNA) to knock down the spermidine/spermine N1-acetyltransferase 1 (Sat1) and arachidonate 15-lipoxygenase (Alox15), and examined damage-associated events including inflammation, ferroptosis, and oxidative stress of chondrocytes. In addition, a destabilization of the medial meniscus (DMM) mouse model of OA induced by surgery was established to investigate the role of Sat1 inhibition in OA progression.

Results

The results showed that inhibition of Sat1 expression can reduce inflammation, ferroptosis changes, reactive oxygen species (ROS) level, and lipid-ROS accumulation induced by IL-1β and Erastin. Knockdown of Sat1 promotes nuclear factor-E2-related factor 2 (Nrf2) signalling. Additionally, knockdown Alox15 can alleviate the inflammation-related protein expression induced by IL-1β and ferroptosis-related protein expression induced by Erastin. Furthermore, knockdown Nrf2 can reverse these protein expression alterations. Finally, intra-articular injection of diminazene aceturate (DA), an inhibitor of Sat1, enhanced type II collagen (collagen II) and increased Sat1 and Alox15 expression.

Conclusion

Our results demonstrate that inhibition of Sat1 could alleviate chondrocyte ferroptosis and inflammation by downregulating Alox15 activating the Nrf2 system, and delaying the progression of OA. These findings suggest that Sat1 provides a new approach for studying and treating OA.

Baicalin inhibits IL-1β-induced ferroptosis in human osteoarthritis chondrocytes by activating Nrf-2 signaling pathway

BACKGROUND

Osteoarthritis (OA) is a common degenerative disease involving articular cartilage, in which ferroptosis of chondrocytes plays an important role. Baicalin (BAI) exerts regulatory effects in a wide range of orthopedic diseases including OA, but its effect on ferroptosis of chondrocytes (CHs) is still unclear. The purpose of this study was to determine the effect of BAI on ferroptosis in human OA chondrocytes (OACs), and to explore its possible mechanism.

METHODS

CHs were treated with IL-1β (10 ng/mL) to simulate inflammation in vitro. Immunofluorescence, quantitative RT-PCR, Western blotting and cell viability assay were performed to evaluate the impacts of BAI on Fe2+ level, mitochondrial dysfunction, ferroptosis-related proteins, oxidative stress and cytotoxicity in CHs. Additionally, siRNA was made use of to knock out nuclear factor E2-related factor 2 (Nrf2) to analyze the role played by Nrf2 in BAI-induced CH ferroptosis.

RESULTS

BAI eliminated IL-1β-induced Fe2+ accumulation, changes in mitochondrial membrane potential and ferroptosis-related protein GPX4, SLC7A11, P53 and ACSL4 levels, as well as reactive oxygen species (ROS), lipid peroxidation (LPO) and malondialdehyde (MDA) accumulation in CHs. Besides, BAI reversed IL-1β-induced decrease of Collagen II and increase of MMP13 in CHs. Meanwhile, BAI attenuated IL-1β-induced CH toxicity and promoted Nrf2 antioxidant system activation. When Nrf2 was knocked down by siRNA, the effects of BAI on IL-1β-induced ferroptosis-related proteins and antioxidant stress in CHs were significantly weakened.

CONCLUSIONS

This study demonstrates that IL-1β can induce CH ferroptosis. BAI is able to inhibit IL-1β-induced CH ferroptosis and ECM degradation, and the specific mechanism may be that it can inhibit IL-1β-induced CH ferroptosis by activating Nrf2 antioxidant system to attenuate the accumulation of intracellular ROS and lipid ROS.

Scientific evidence supporting the newly developed one-health labeling tool "Med-Index": an umbrella systematic review on health benefits of mediterranean diet principles and adherence in a planeterranean perspective

BACKGROUND

Med-Index is a one-health front-of-pack (FOP) label, based on Mediterranean diet (MedDiet) principles, developed to summarize information about the nutritional properties and related-health benefits of any food as well as its sustainable production processes, and the associated food company's social responsibility parameters in a new "Planeterranean" perspective. Thus, Med-Index can be adopted in and by any European region and authority as well as worldwide; this is achieved by consumption and cooking of locally available and sourced foods that respect MedDiet principles, both in terms of healthy nutrition and sustainable production. The huge body of scientific evidence about the health benefits of the MedDiet model and principles requires a comprehensive framework to encompass the scientific reliability and robustness of this tool. A systematic review was carried out to examine the association between human health and adherence to MedDiet patterns upon which the "Med-Index" tool was subsequently developed.

METHODS

MEDLINE and PubMed databases were searched for eligible publications from 1990 to April 2023. Systematic literature reviews, with or without meta-analysis, of clinical trials and observational studies were screened by two independent investigators for eligibility, data extraction, and quality assessment. English language and the time interval 1990-2023 were applied. A registry code CRD42023464807 was generated on PROSPERO and approved for this search protocol. The corrected covered area (CCA), calculated to quantify the degree of overlap between reviews, gave a slight overlap (CCA = 4%).

RESULTS

A total of 84 systematic reviews out of 6681 screened records were selected. Eligible reviews included studies with predominantly observational designs (61/84, 72.6%%), of which 26/61 referenced studies of mixed observational and RCT designs, while 23/84 (27.4%) were RCT-only systematic reviews. Seventy-nine different entries were identified for health outcomes, clustered into 10 macro-categories, each reporting a statistically significant association with exposure to the MedDiet. Adherence to MedDiet was found to strongly benefit age-related chronic diseases (21.5%), neurological disorders (19%), and obesity-related metabolic features (12.65), followed by CVDs (11.4%), cancer (10.1%), diabetes (7.5%), liver health (6.3%), inflammation (5%), mortality (5%), and renal health (1.2%). The quality of the studies was moderate to high.

CONCLUSION

In the context of a "Planeterranean" framework and perspective that can be adopted in any European region and worldwide, MedDiet represents a healthy and sustainable lifestyle model, able to prevent several diseases and reduce premature mortality. In addition, the availability of a FOP, such as Med-Index, might foster more conscious food choices among consumers, paying attention both to human and planetary health.

[The potential of nutrition for pain management and planetary health]

The consumption of western diets that are often rich in animal-source foods and low in wholesome, plant-based foods, has grave implications for public health. This is expressed in a growing prevalence of obesity as well as high rates of cardiovascular and metabolic diseases and some cancers. At the same time, current global dietary patterns are major contributors to global environmental challenges, i.e. the climate and the biodiversity crisis, and are thereby a major threat to planetary health. Shifting to more plant-based diets, e.g. in line with the "Planetary Health Diet", provides a major opportunity to improve individual and planetary health. Plant-based dietary patterns with an increase in the consumption of anti-inflammatory and a decrease in pro-inflammatory substances can also lead to improvements in pain symptoms, especially in inflammatory or degenerative joint diseases. In addition, dietary shifts are a prerequisite to achieve global environmental targets and thereby ensure a livable and healthy future for everyone. Medical professionals therefore have a special responsibility to actively promote this transformation.

Fundamentals of osteoarthritis. Rehabilitation: Exercise, diet, biomechanics, and physical therapist-delivered interventions

Insights related to the pathogenesis of osteoarthritis (OA) have informed rehabilitative treatments that aim to mitigate the influence of several known impairments and risk factors for OA, with the goal to improve pain, function, and quality of life. The purpose of this invited narrative review is to provide fundamental knowledge to non-specialists about exercise and education, diet, biomechanical interventions, and other physical therapist-delivered treatments. In addition to summarizing the rationale for common rehabilitative therapies, we provide a synthesis of current core recommendations. Robust evidence based on randomized clinical trials supports exercise with education and diet as core treatments for OA. Structured, supervised exercise therapy is advised. The mode of exercise may vary but should be individualized. The dose should be based on an initial assessment, the desired physiological changes, and progressed when appropriate. Diet combined with exercise is strongly recommended and studies demonstrate a dose-response relationship between the magnitude of weight loss and symptom improvement. Recent evidence suggests the use of technology to remotely deliver exercise, diet and education interventions is cost-effective. Although several studies support the mechanisms for biomechanical interventions (e.g., bracing, shoe inserts) and physical therapist-delivered (passive) treatments (e.g., manual therapy, electrotherapeutic modalities) fewer rigorous randomized trials support their clinical use; these therapies are sometimes recommended as adjuncts to core treatments. The mechanisms of action for all rehabilitative interventions include contextual factors such as attention and placebo effects. These effects can challenge our interpretation of treatment efficacy from clinical trials, yet also provide opportunities to maximize patient outcomes in clinical practice. When evaluating rehabilitative interventions, the field may benefit from increased emphasis on research that considers contextual factors while evaluating mechanistic, longer-term, clinically-important and policy-relevant outcome measures.

Curcumin reverses erastin-induced chondrocyte ferroptosis by upregulating Nrf2

Osteoarthritis (OA) is associated with ferroptosis, a newly discovered form of programmed cell death associated with lipid peroxidation. Curcumin, the main monomer component in turmeric rhizomes, possesses antioxidant and anti-ferroptosis properties, but its effect on ferroptosis in chondrocytes of OA is unknown. This study aimed to investigate the protective effect and potential mechanism of curcumin on chondrocytes induced by erastin, a ferroptosis inducer. CCK-8 assays were used to assess cell viability in mouse primary chondrocytes treated with 3.33 μM erastin alone or in combination with different doses of curcumin. Various parameters were detected, including LDH, SOD, GSH-PX, MDA, ROS and Fe2+ contents. The ferroptosis-related proteins, such as SLC7A11, GPX4, TFR1, ACSL4, and FTH1, were examined using immunofluorescence and western blotting. Nrf2 was knocked down using siRNA to explore the molecular mechanism through which curcumin protects chondrocytes from erastin-induced ferroptosis. In a mouse model of knee ferroptosis induced by intracavity injection of 10 μL erastin (5 mg/mL), HE staining, Safranin O-Fast Green staining, and immunohistochemistry were employed to evaluate articular cartilage injury. The results demonstrated that erastin significantly suppressed the expression of SOD, GSH-PX, SLC7A11, GPX4, and FTH1 while upregulating the levels of LDH, MDA, ROS, ACSL4, and TFR1 in chondrocytes. Moreover, erastin-induced chondrocyte ferroptosis, lipid ROS, and Fe2+ production were reversed by curcumin. Additionally, curcumin significantly upregulated the expression level of the Nrf2 gene and protein. Silencing Nrf2 reversed the protective effect of curcumin on erastin-induced chondrocyte ferroptosis. In animal experiments, silencing Nrf2 counteracted the impact and damage of curcumin on erastin-induced ferroptosis of cartilage tissue in vivo, leading to significant inhibition of OA progression. Taken together, these findings suggest that curcumin can inhibit chondrocyte ferroptosis by activating the Nrf2 signaling pathway, providing further insight into the regulatory mechanism of curcumin in OA and supporting its potential therapeutic use in OA treatment.

Knee osteoarthritis: Current status and research progress in treatment (Review)

Knee osteoarthritis (KOA) is a common chronic articular disease worldwide. It is also the most common form of OA and is characterized by high morbidity and disability rates. With the gradual increase in life expectancy and ageing population, KOA not only affects the quality of life of patients, but also poses a burden on global public health. OA is a disease of unknown etiology and complex pathogenesis. It commonly affects joints subjected to greater loads and higher levels of activity. The knee joint, which is the most complex joint of the human body and bears the greatest load among all joints, is therefore most susceptible to development of OA. KOA lesions may involve articular cartilage, synovium, joint capsule and periarticular muscles, causing irreversible articular damage. Factors such as mechanical overload, inflammation, metabolism, hormonal changes and ageing serve key roles in the acceleration of KOA progression. The clinical diagnosis of KOA is primarily based on combined analysis of symptoms, signs, imaging and laboratory examination results. At present, there is no cure for KOA and the currently available therapies primarily focus on symptomatic treatment and delay of disease progression. Knee replacement surgery is typically performed in patients with advanced disease. The current study presents a review of epidemiological characteristics, risk factors, histopathological manifestations, pathogenesis, diagnosis, treatment modalities and progress in KOA research.

Evidence-Based Dietary Practices to Improve Osteoarthritis Symptoms: An Umbrella Review

While there is some research investigating whole foods or diets that are easily understood and accessible to patients with osteoarthritis, specific nutrients or nutraceuticals are more commonly identified. Unfortunately, guidelines and evidence surrounding individual nutrients, extracts, and nutraceuticals are conflicting and are more difficult to interpret and implement for patients with osteoarthritis. The purpose of this umbrella review is to provide a comprehensive understanding of the existing evidence of whole foods and dietary patterns effects on osteoarthritis-related outcomes to inform evidence-based recommendations for healthcare professionals and identify areas where more research is warranted. A literature search identified relevant systematic reviews/meta-analyses using five databases from inception to May 2022. Five systematic reviews/meta-analyses were included in the current umbrella review. Most evidence supported the Mediterranean diet improving osteoarthritis-related outcomes (e.g., pain, stiffness, inflammation, biomarkers of cartilage degeneration). There was little to no evidence supporting the effects of fruits and herbs on osteoarthritis-related outcomes; however, there was some suggestion that specific foods could potentiate symptom improvement through antioxidative mechanisms. The overall lack of homogeneity between the studies limits the conclusions that can be made and highlights the need for quality research that can identify consumer-accessible foods to improve osteoarthritis-related symptoms.

Beyond Seasoning-The Role of Herbs and Spices in Rheumatic Diseases

Although we have witnessed remarkable progress in understanding the biological mechanisms that lead to the development of rheumatic diseases (RDs), remission is still not achieved in a substantial proportion of patients with the available pharmacological treatment. As a consequence, patients are increasingly looking for complementary adjuvant therapies, including dietary interventions. Herbs and spices have a long historical use, across various cultures worldwide, for both culinary and medicinal purposes. The interest in herbs and spices, beyond their seasoning properties, has dramatically grown in many immune-mediated diseases, including in RDs. Increasing evidence highlights their richness in bioactive molecules, such as sulfur-containing compounds, tannins, alkaloids, phenolic diterpenes, and vitamins, as well as their antioxidant, anti-inflammatory, antitumorigenic, and anticarcinogenic properties. Cinnamon, garlic, ginger, turmeric, and saffron are the most popular spices used in RDs and will be explored throughout this manuscript. With this paper, we intend to provide an updated review of the mechanisms whereby herbs and spices may be of interest in RDs, including through gut microbiota modulation, as well as summarize human studies investigating their effects in Rheumatoid Arthritis, Osteoarthritis, and Fibromyalgia.

Effects of Prolonged Fasting during Inpatient Multimodal Treatment on Pain and Functional Parameters in Knee and Hip Osteoarthritis: A Prospective Exploratory Observational Study

Preliminary clinical data suggest that pain reduction through fasting may be effective for different diagnoses. This uncontrolled observational clinical study examined the effects of prolonged modified fasting on pain and functional parameters in hip and knee osteoarthritis. Patients admitted to the inpatient department of Internal Medicine and Nature-based Therapies of the Immanuel Hospital Berlin between February 2018 and December 2020 answered questionnaires at the beginning and end of inpatient treatment, as well as at 3, 6, and 12 months after discharge. Additionally, selected blood and anthropometric parameters, as well as subjective pain ratings, were routinely assessed during the inpatient stay. Fasting was the only common intervention for all patients, being performed as part of a multimodal integrative treatment program, with a daily caloric intake of <600 kcal for 7.7 ± 1.7 days. N = 125 consecutive patients were included. The results revealed an amelioration of overall symptomatology (WOMAC Index score: -14.8 ± 13.31; p < 0.001; d = 0.78) and pain alleviation (NRS Pain: -2.7 ± 1.98, p < 0.001, d = 1.48). Pain medication was reduced, stopped, or replaced by herbal remedies in 36% of patients. Improvements were also observed in secondary outcome parameters, including increased quality of life (WHO-5: +4.5 ± 4.94, p < 0.001, d = 0.94), reduced anxiety (HADS-A: -2.1 ± 2.91, p < 0001, d = 0.55) and depression (HADS-D: -2.3 ± 3.01, p < 0.001, d = 0.65), and decreases in body weight (-3.6 kg ± 1.65, p < 0.001, d = 0.21) and blood pressure (systolic: -6.2 ± 15.93, p < 0.001, d = 0.43; diastolic: -3.7 ± 10.55, p < 0.001, d = 0.43). The results suggest that patients with osteoarthritis of the lower extremities may benefit from prolonged fasting as part of a multimodal integrative treatment to improve quality of life, pain, and disease-specific functional parameters. Confirmatory randomized controlled trials are warranted to further investigate these hypotheses.

Dihydrocaffeic acid improves IL-1β-induced inflammation and cartilage degradation via inhibiting NF-κB and MAPK signalling pathways

Aims

Osteoarthritis (OA) is a prevalent joint disorder with inflammatory response and cartilage deterioration as its main features. Dihydrocaffeic acid (DHCA), a bioactive component extracted from natural plant (gynura bicolor), has demonstrated anti-inflammatory properties in various diseases. We aimed to explore the chondroprotective effect of DHCA on OA and its potential mechanism.

Methods

In vitro, interleukin-1 beta (IL-1β) was used to establish the mice OA chondrocytes. Cell counting kit-8 evaluated chondrocyte viability. Western blotting analyzed the expression levels of collagen II, aggrecan, SOX9, inducible nitric oxide synthase (iNOS), IL-6, matrix metalloproteinases (MMPs: MMP1, MMP3, and MMP13), and signalling molecules associated with nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. Immunofluorescence analysis assessed the expression of aggrecan, collagen II, MMP13, and p-P65. In vivo, a destabilized medial meniscus (DMM) surgery was used to induce mice OA knee joints. After injection of DHCA or a vehicle into the injured joints, histological staining gauged the severity of cartilage damage.

Results

DHCA prevented iNOS and IL-6 from being upregulated by IL-1β. Moreover, the IL-1β-induced upregulation of MMPs could be inhibited by DHCA. Additionally, the administration of DHCA counteracted IL-1β-induced downregulation of aggrecan, collagen II, and SOX9. DHCA protected articular cartilage by blocking the NF-κB and MAPK pathways. Furthermore, DHCA mitigated the destruction of articular cartilage in vivo.

Conclusion

We present evidence that DHCA alleviates inflammation and cartilage degradation in OA chondrocytes via suppressing the NF-κB and MAPK pathways, indicating that DHCA may be a potential agent for OA treatment.

The effects of dietary patterns and food groups on symptomatic osteoarthritis: A systematic review

AIM

To systematically review current literature to determine the association between symptomatic osteoarthritis and dietary patterns, diet quality and food groups in adults aged ≥45 years.

METHODS

The review was registered on PROSPERO (CRD42021270891). Cochrane Central Library, Cumulative Index of Nursing and Allied Health Literature, Embase, Medline and Web of Science databases were searched. A total of 3816 records were identified. Eligible articles involved populations aged ≥45 years with symptomatic osteoarthritis, assessing dietary patterns, diet quality or food groups, with pain in joints as outcomes. The Joanna Briggs Institute Critical Appraisal Checklists were used for quality assessment. Grading of Recommendations, Assessment, Development and Evaluation was used to assess the certainty of evidence.

RESULTS

Six cohort studies were included. The Prudent dietary pattern and the Mediterranean dietary pattern reduced the progression of osteoarthritis symptoms. The Western dietary pattern increased symptomatic osteoarthritis progression. Increased total fibre consumption reduced symptomatic osteoarthritis progression and pain worsening, but the effects of fibre from each food group were inconclusive. Diet with high inflammatory potential increased risk of new onset symptomatic osteoarthritis, but the effects of overall diet quality were inconclusive.

CONCLUSIONS

The Prudent dietary pattern showed the highest protection on symptomatic osteoarthritis in adults aged 45 years and over. The body of evidence is limited, suggesting that further research is needed to corroborate the estimated effect at a high certainty of evidence, and to incorporate previously unstudied dietary patterns and food groups. Identifying the most beneficial dietary pattern may inform future guidelines for reducing symptomatic osteoarthritis in middle aged and older adults.

A Scoping Review of the Use of Pioglitazone in the Treatment of Temporo-Mandibular Joint Arthritis

Thiazolidinediones (TZDs) are a group of diabetes medications currently being investigated for anti-arthritis effectiveness, one of which is pioglitazone. The purpose of this scoping review is to evaluate the potential use of pioglitazone in the treatment of temporomandibular joint (TMJ) arthritis. The criteria of eligibility were studies with the diagnosis of arthritis and pioglitazone treatment with a change in any inflammation index as an outcome. Of the 1169 records initially identified following the selection process, two animal studies and four clinical studies were included in the review. Improvements from the baseline were observed in each treatment group for each inflammation indicator. The results of the animal studies on the temporomandibular joints and on patients with rheumatoid and psoriatic arthritis indicate that the drug in question may have potential to treat arthritis, including within the temporomandibular joint.

Correlation of synovial tissue protein abundance with menopause in osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a common articular disorder. Epidemiologic surveys show a higher prevalence of OA in women than men and that morbidity is higher during menopause. We aimed to explore whether menopause influences the clinical recovery of a knee joint following OA and injury, and identify associated mechanisms by analyzing the proteomic profile of synovial tissue (ST) samples.

METHODS

Routine blood examination and hormone level tests were conducted before surgery. ST samples from eight participants were collected intraoperatively for proteomic analysis. One day before and one month after the surgery, we assessed various aspects of function in the affected knee including the with Visual Analog Score (VAS), Lysholm, The Western Ontario, and McMaster Universities Osteoarthritis Index (WOMAC) scores. The relationships between proteomic data, estrogen levels, and affected knee function were compared and analyzed. This was a retrospective study.

RESULT

Menopause was associated with the clinical outcomes of knee OA and knee injuries. ST proteomic data identified that 80 proteins in premenopausal OA females were significantly different from menopausal OA females. In addition, 100 proteins were significantly different between premenopausal OA females and premenopausal injured females.

CONCLUSIONS

Age and menopause showed a positive correlation with the protein profile of ST from OA or knee injury female patients, indicating that the protein components might be affected by menopause. Postoperative clinical outcomes were affected by menopause. We conclude that menopause may, in part, regulate knee joint function by altering ST protein expression.

Drug-Food Interactions with a Focus on Mediterranean Diet

There is a growing interest among people in western countries for adoption of healthier lifestyle habits and diet behaviors with one of the most known ones to be Mediterranean diet (Med-D). Med-D is linked with daily consumption of food products such as vegetables, fruits, whole grains, seafood, beans, nuts, olive oil, low-fat food derivatives and limited consumption of meat or full fat food products. Med-D is well-known to promote well-being and lower the risk of chronic conditions such as cardiovascular diseases, diabetes, and metabolic syndrome. On the other hand bioactive constituents in foods may interfere with drugs’ pharmacological mechanisms, modulating the clinical outcome leading to drug-food interactions (DFIs). This review discusses current evidence for food products that are included within the Med-Dand available scientific data suggest a potential contribution in DFIs with impact on therapeutic outcome. Most cases refer to potential modulation of drugs’ absorption and metabolism such as foods’ impact on drugs’ carrier-mediated transport and enzymatic metabolism as well as potential synergistic or antagonistic effects that enhance or reduce the pharmacological effect for some drugs. Adherence to Med-D can improve disease management and overall well-being, but specific foods should be consumed with caution so as to not hinder therapy outcome. Proper patient education and consultation from healthcare providers is important to avoid any conflicts and side effects due to clinically significant DFIs.

The effects and significance of gut microbiota and its metabolites on the regulation of osteoarthritis: Close coordination of gut-bone axis

Osteoarthritis (OA) is a common chronic degenerative disease of articular cartilage in middle-aged and older individuals, which can result in the joint pain and dysfunction, and even cause the joint deformity or disability. With the enhancing process of global aging, OA has gradually become a major public health problem worldwide. Explaining pathogenesis of OA is critical for the development of new preventive and therapeutic interventions. In recent years, gut microbiota (GM) has been generally regarded as a “multifunctional organ,” which is closely relevant with a variety of immune, metabolic and inflammatory functions. Meanwhile, more and more human and animal researches have indicated the existence of gut-bone axis and suggested that GM and its metabolites are closely involved in the pathogenic process of OA, which might become a potential and promising intervention target. Based on the close coordination of gut-bone axis, this review aims to summarize and discuss the mechanisms of GM and its metabolites influencing OA from the aspects of the intestinal mucosal barrier modulation, intestinal metabolites modulation, immune modulation and strategies for the prevention or treatment of OA based on perspectives of GM and its metabolites, thus providing a profound knowledge and recognition of it.