Is There a Role for Diet in the Therapy of Rheumatoid Arthritis?

Effect of Plant-Based Diets on Rheumatoid Arthritis: A Systematic Review

CONTEXT

Rheumatoid arthritis (RA) is an autoimmune disease that leads to chronic inflammation and joint damage. Various plant-based diets are thought to have effects on RA symptoms and disease activity.

OBJECTIVE

Relevant literature on the effect of different types of plant-based diets on RA was reviewed.

DATA SOURCES

A systematic search was conducted using the Web of Science, PubMed, Scopus, and Cochrane databases and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA EXTRACTION

Articles on observational and interventional human studies carried out in the adult population and published in English between February 2013 and April 2023 were eligible for inclusion. Articles reporting on studies performed in populations under 18 years of age, with unclear methods and results, or for which the full text was unavailable were excluded. The risk of bias in the selected studies was assessed using the Joanna Briggs Institute checklists.

DATA ANALYSIS

Of 547 screened articles, 15 were included, comprising 4 cross-sectional, 2 cohort, and 9 randomized controlled trials. These studies examined the effects of various diets, including the Mediterranean, low-fat high-carbohydrate, anti-inflammatory, and vegan, on RA. Results indicate adherence to plant-based diets generally reduced disease severity and improved dietary intake, physical activity, body weight, and key clinical markers such as the Disease Activity Score-28, Visual Analog Scale score, Health Assessment Questionnaire Disability Index, erythrocyte sedimentation rate, and C-reactive protein level in patients with in RA.

CONCLUSIONS

Most of the studies suggested the Mediterranean diet may positively affect the severity of RA. However, the included studies show heterogeneity. Therefore, more randomized controlled studies are needed in this area to increase understanding of the effect of diet on RA and facilitate the implementation of strategies to prevent RA.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023420577.

β-hydroxybutyrate suppresses pathological changes of blood-induced arthropathy in rats

Arthropathy is a common complication in haemophilia and decreases quality of life. It has been known that concentrations of β-hydroxybutyrate (BHB) in blood are increased by a ketogenic diet, and elevated levels of circulating BHB restricts the progression of inflammation-mediated joint pathological changes. We hypothesized that elevation of blood BHB concentrations could be effective for reducing the progression of bleeding-induced arthropathy by moderating the inflammatory responses of macrophages. In this study, we investigated whether BHB alleviates the arthropathy caused by repeated intra-articular blood injection in rats. To increase blood BHB levels, rats were fed with ketogenic diet. Repeated intra-articular blood injection induced significant joint swelling, whereas ketogenic diet intake significantly increased blood BHB concentrations and ameliorated the joint swelling. The periarticular tissue-fibrosis observed in the control diet intake group appeared to be significantly alleviated in the ketogenic diet intake group. In addition, the IL-1β, which is involved in the progression of arthropathy, levels in the supernatants of blood-exposed macrophages derived from THP-1 cell line were significantly suppressed by BHB supplementation. In summary, BHB moderated the pathological joint changes caused by intra-articular blood exposure.

Interdisciplinary Rheumatoid Arthritis Research and Patient Care: An Introduction and Critique of the Biopsychosocial Model of Disease Experience in Rheumatoid Arthritis

INTRODUCTION

Rheumatoid arthritis (RA), a debilitating autoimmune disease, affects approximately 78 million people globally. RA is often managed solely by rheumatology providers, but an interdisciplinary approach to RA may be the key to improving health equity and outcomes. An interdisciplinary model is an important step towards this goal. The Biopsychosocial Model of Disease Experience in RA (BDRA) is a conceptual approach that considers individual disease determinants in interdisciplinary research and care.

OBJECTIVE

To introduce and critique the evidence-based, interdisciplinary BDRA.

METHODS

Engel's Biopsychosocial Model of Health (BMH) and the Revised Symptom Management Conceptual Model (RSMCM) were blended in the BDRA. A literature search of articles published prior to December 2021 was completed using "disease exacerbation," "disease improvement," and "disease activity" in RA. Results were categorized as biological, psychological, and social determinants of disease activity in RA. These biopsychosocial factors alter biological function and result in the individual RA experience. Model development and critique were completed using guidelines established by Walker and Avant.

CONCLUSION

The BDRA is a visual depiction of RA biopsychosocial factors, disease activity, and individual experience. This model can guide interdisciplinary research and patient care, in efforts to improve RA health equity and rates of sustained remission.

Environment and systemic autoimmune rheumatic diseases: an overview and future directions

Introduction

Despite progress in our understanding of disease pathogenesis for systemic autoimmune rheumatic diseases (SARD), these diseases are still associated with high morbidity, disability, and mortality. Much of the strongest evidence to date implicating environmental factors in the development of autoimmunity has been based on well-established, large, longitudinal prospective cohort studies.

Methods

Herein, we review the current state of knowledge on known environmental factors associated with the development of SARD and potential areas for future research.

Results

The risk attributable to any particular environmental factor ranges from 10-200%, but exposures are likely synergistic in altering the immune system in a complex interplay of epigenetics, hormonal factors, and the microbiome leading to systemic inflammation and eventual organ damage. To reduce or forestall the progression of autoimmunity, a better understanding of disease pathogenesis is still needed.

Conclusion

Owing to the complexity and multifactorial nature of autoimmune disease, machine learning, a type of artificial intelligence, is increasingly utilized as an approach to analyzing large datasets. Future studies that identify patients who are at high risk of developing autoimmune diseases for prevention trials are needed.

Effects of a telehealth-delivered Mediterranean diet intervention in adults with Rheumatoid Arthritis (MEDRA): a randomised controlled trial

OBJECTIVE

To compare the effects a Mediterranean diet (MedDiet) versus the Irish Healthy Eating Guidelines (HEG) on physical function and quality of life in adults with rheumatoid arthritis (RA) in Ireland.

METHODS

Forty-four adults with RA were randomised (1:1) to the MedDiet or HEG for 12 weeks. The intervention included three video teleconsultations and two follow-up telephone calls facilitated by a Registered Dietitian (RD). Changes in physical function by Health Assessment Questionnaire- Disability Index (HAQ-DI) and quality of life by Rheumatoid Arthritis Quality of Life Questionnaire (RAQoL) were the primary outcomes measured. Secondary outcomes included changes in dietary adherence, physical activity by Yale Physical Activity survey (YPAS), patient-perceived pain and general health, and anthropometric measures. All measurements were administered at baseline and repeated at 6 and 12 weeks.

RESULTS

Forty participants completed the study. Participants were primarily females (87.5%), mean age was 47.5 ± 10.9 years. At the end of the intervention, participants in the MedDiet group reported significantly better physical function (p = 0.006) and quality of life (p = 0.037) compared to HEG group. From baseline to 12 weeks, physical function significantly improved in both diet groups, MedDiet (0.9 ± 0.5 to 0.5 ± 0.4 units, p < 0.001) and HEG (1.4 ± 0.7 to 1.0 ± 0.6 units, p < 0.001). Quality of life also significantly improved in the MedDiet (10.1 ± 7.5 to 4.0 ± 4.7 units, p < 0.001) and HEG group (11.25 ± 7.2 to 7.9 ± 6.4 units, p = 0.048). Physical activity improved significantly in the MedDiet (56.7 ± 28.6 to 70.6 ± 33.5 points, p = 0.01) but not within the HEG group despite similar recommendations.

CONCLUSION

Adhering to the MedDiet and Irish Healthy Eating Guidelines resulted in improvements in RA patient-reported outcomes. The changes observed in both diet groups are likely due to the improvement in overall diet quality irrespective of dietary prescription.

TRIAL REGISTRATION NUMBER

NCT04262505.

Joint effects of one year of marine omega-3 fatty acid supplementation and participant dietary fish intake upon circulating lipid mediators of inflammation resolution in a randomized controlled trial

OBJECTIVES

We assessed the joint effects of omega (n)-3 fatty acid supplementation and dietary fish intake on systemic lipid mediators of inflammation among adults.

METHODS

Within VITAL, a double-blind randomized controlled trial, adults were randomized to ω-3 fatty acids (460 mg EPA + 380 mg DHA/d) or placebo. We selected participants who reported low (<1 serving/mo) baseline dietary fish intake and matched them by age, sex, race, and trial arm to participants with self-reported highest fish intake (≥3.9 servings/wk). Baseline and 1-y plasma samples were tested for 9 ω-3 fatty acid-derived lipid mediators. Multivariable linear models assessed lipid mediator changes and joint effects of ω-3 fatty acid supplementation and dietary fish intake.

RESULTS

Forty-eight participants with low baseline fish intake were matched to 48 with high fish intake. Mean age was 64.6 (±7.26), 50% were female, and 85% non-Hispanic white. One-year lipid mediator changes in expected directions were observed in those receiving ω-3 fatty acids versus placebo: reductions in proinflammatory mediators, PGD2, 5-HETE, and 12-HETE; increases in proresolving mediators, EPA and DHA. Larger 1-y lipid biomarker changes were seen in those with low baseline fish intake randomized to active ω-3 fatty acids for DHA, EPA, PGD2, Resolvin D1, and Resolvin D4 were observed, although no significant multiplicative interactions were detected.

DISCUSSION

Beneficial changes in circulating proresolving and proinflammatory mediators were found with 1-y of ω-3 fatty acid supplementation versus placebo for all participants, with a trend toward larger effects among those with low baseline fish intake, although interactions were not significant.

Integrative non-pharmacological care for individuals at risk of rheumatoid arthritis

There is increasing knowledge in the recognition of individuals at risk for progression to rheumatoid arthritis (RA) before the clinical manifestation of the disease. This prodromal phase preceding the manifestation of RA may represent a "window of opportunity" for preventive interventions that may transform the clinical approach to this disease. However, limited evidence exists in support of effective interventions to delay the onset or even halt the manifestation of RA. Given the multifactorial nature of RA development and disease progression, the latest guidelines for established RA stress the use of integrative interventions and multidisciplinary care strategies, combining pharmacologic treatment with non-pharmacological approaches. Accordingly, individuals at risk of RA could be offered an integrative, multifactorial intervention approach. Current data point toward pharmacological intervention reverting the subclinical inflammation and delay in the disease onset. In addition, targeting life style modifiable factors (smoking cessation, dental health, physical activity, and diet) may presumably improve RA prognosis in individuals at risk, mainly by changes in epigenetics, autoantibodies, cytokines profiles, and microbiome. Nonetheless, the benefits of multidisciplinary interventions to halt the manifestation of RA in at-risk individuals remain unknown. As there is a growing knowledge of possible pharmacological intervention in the preclinical phase, this narrative review aims to provide a comprehensive overview of non-pharmacological treatments in individuals at risk of RA. Considering the mechanisms preceding the clinical manifestation of RA we explored all aspects that would be worth modifying and that would represent an integrative non-pharmacological care for individuals at risk of RA.

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.

The role of the microbiome in rheumatoid arthritis: a review

The close bidirectional relationship between the microbiome and the immune system is well supported, and a role of gut dysbiosis has been implied in many systemic autoimmune diseases. This review aims to provide a critical summary and appraisal of 6 murine studies and 16 clinical studies. The findings of the literature review suggest that gut dysbiosis precedes arthritis and that local intestinal inflammation leads to systemic inflammation in genetically predisposed individuals. However, the exact mechanism by which microorganisms provoke immune responses at distal sites remains to be elucidated. Although a characteristic RA microbiome was not identified, there were some common findings among studies: overabundance of Prevotella copri in early RA patients, and proliferation of the genus Collinsela and some Lactobacillus species. Three mechanisms by which microbiota might contribute to RA pathogenesis were proposed: inflammatory responses (P. copri and Lactobacillus), molecular mimicry (P. copri) and loss of intestinal barrier integrity (Collinsella). Larger longitudinal studies are required in order to shed light on the mechanisms involved and unravel the therapeutic potential of the microbiome, and clinical trials are needed to evaluate the safety and efficacy of the implied therapeutic interventions.

Olive Oil and Nuts in Rheumatoid Arthritis Disease Activity

Few observational studies investigated the relationship between single food groups and disease activity in rheumatoid arthritis (RA). Within a recent Italian cross-sectional study (365 patients, median age: 58.46 years, 78.63% females), we focused on two food groups, olive oil and nuts, representing vegetable sources of fatty acids. Disease activity was measured with Disease Activity Score on 28 joints based on C-reactive protein (DAS28-CRP) and the Simplified Disease Activity Index (SDAI). Robust linear and logistic regression models included tertile-based consumption categories of each food group and several confounders. Stratified analyses were performed by disease severity or duration. Higher consumption of both food groups exerted a favorable effect on disease activity, significant only for olive oil (Beta: -0.33, p-value: 0.03) in the linear regression on the overall sample. This favorable effect was stronger in the more severe or long-standing forms of RA (p-value for heterogeneity <0.05, especially for disease severity). Significant ORs were as low as ~0.30 for both food groups, strata (i.e., more severe and long-standing RA), and disease activity measures. Mean DAS28-CRP significantly decreased by ~0.70 for olive oil and ~0.55 for nuts in the two strata; mean SDAI significantly decreased by 3.30 or more for olive oil in the two strata. Globally, the beta coefficients doubled, and the ORs halved (in absolute values) for both food groups, reaching significance in 12 of the 16 available models fitted to the more severe or long-standing RA strata. More compromised forms of RA may benefit from increasing consumption of olive oil, olives, and nuts.

Diet and the risk of rheumatoid arthritis - A systematic literature review

OBJECTIVES

Diet has received attention as a factor possibly contributing to the development of Rheumatoid arthritis (RA). Several dietary exposures have been examined in various populations using different diet assessment methods. The aim of this study was to systematically assess the literature on the relation between dietary patterns, different food and food groups, macronutrients, non-alcoholic beverages and the risk of developing RA.

METHODS

A systematic literature search was performed to identify relevant articles on diet and the risk of developing RA. The selection of articles and overall quality assessment of all included studies were performed independently by two examiners. Overall study quality was evaluated using the Newcastle-Ottawa Scales. We excluded all articles where the temporal relation between dietary data collection and time of RA diagnosis was not presented. Main findings were summarized for cohort-based studies and case-control studies separately.

RESULTS

A total of 984 articles were screened. Nineteen relevant cohort-based studies, and eight case-control studies, were included in our review. Two articles were excluded due to lacking data on the relation between RA diagnosis and time of dietary data collection and one due to incorrect outcome. Identified studies suggested protective effects of fish, vegetables and Mediterranean-style diets, although study results and methods were heterogenous. An issue in some case-control studies was that unvalidated diet assessment methods were used. A vast majority of the cohort-based studies used validated diet assessment methods, although the definitions of exposures studied varied.

CONCLUSION

There is lack of consistent evidence on the role of diet in the development of RA, partly due to differences in study quality and methodology Limited evidence suggests that some healthy eating habits may reduce the risk of RA. More high-quality studies in the area are needed for a deeper understanding of the effect of diet, and to enable strategies to prevent RA.

To eat or not to eat—an exploratory randomized controlled trial on fasting and plant-based diet in rheumatoid arthritis (NutriFast-Study)

Background

Fasting is beneficial in many diseases, including rheumatoid arthritis (RA), with lasting effects for up to 1 year. However, existing data dates back several decades before the introduction of modern therapeutic modalities.

Objective

This exploratory RCT compares the effects of a 7-day fast followed by a plant-based diet (PBD) to the effects of the dietary recommendations of the German society for nutrition (Deutsche Gesellschaft für Ernährung, DGE) on RA disease activity, cardiovascular (CV) risk factors, and well-being.

Methods

In this RCT we randomly assigned 53 RA patients to either a 7-day fast followed by an 11-week PBD or a 12-week standard DGE diet. The primary endpoint was the group change from baseline to 12 weeks on the Health Assessment Questionnaire Disability Index (HAQ-DI). Further outcomes included other disease activity scores, body composition, and quality of life.

Results

Of 53 RA patients enrolled, 50 participants (25 per group) completed the trial and were included into the per-protocol analysis. The primary endpoint was not statistically significant. However, HAQ-DI improved rapidly in the fasting group by day 7 and remained stable over 12 weeks (Δ-0.29, p = 0.001), while the DGE group improved later at 6 and 12 weeks (Δ-0.23, p = 0.032). DAS28 ameliorated in both groups by week 12 (Δ-0.97, p < 0.001 and Δ-1.14, p < 0.001; respectively), with 9 patients in the fasting but only 3 in the DGE group achieving ACR50 or higher. CV risk factors including weight improved stronger in the fasting group than in the DGE group (Δ-3.9 kg, p < 0.001 and Δ-0.7 kg, p = 0.146).

Conclusions

Compared with a guideline-based anti-inflammatory diet, fasting followed by a plant-based diet showed no benefit in terms of function and disability after 12 weeks. Both dietary approaches had a positive effect on RA disease activity and cardiovascular risk factors in patients with RA.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT03856190, identifier: NCT03856190.

Arsenic trioxide modulates the composition and metabolic function of the gut microbiota in a mouse model of rheumatoid arthritis

The mechanism of rheumatoid arthritis (RA) has been widely investigated, and studies on the use of arsenic trioxide (ATO) in the treatment of RA have been reported in recent years. However, the exact mechanism of action of ATO in RA remains unclear. This study explores alterations in the gut microbiota and metabolism during ATO treatment in a mouse model of RA and provides an integrative analysis of the biomechanism. The purpose of this study was to verify whether ATO can alleviate RA by altering the gut microbiota. In this study, the mice were randomly divided into four different groups: the normal control (NC) group, the collagen-induced arthritis (CIA) group, the ATO 1.0 mg/kg/day group, and the ATO 2.0 mg/kg/day group. Fecal samples were collected. Through 16S rDNA gene sequencing and metabolomic analysis, the effect of ATO on the composition and metabolites of gut microbiota in CIA mice was investigated. The results showed that compared with NC mice, CIA mice showed differences at both the phylum level (Firmicutes and Bacteroidetes) and the genus level (Muribaculaceae_unclassified and Alistipes). Meanwhile, many metabolites were significantly changed between the two groups, including benzoic acid and (s)-2-acetolactate. However, these alterations were partially reversed in ATO-treated CIA mice. These results indicated that ATO treatment modulated gut microbiota disorder and improved fecal metabolite abnormalities. In conclusion, this study provided important evidence for alterations of the gut microbiota and metabolites and the role of these alterations in a potential novel mechanism of ATO treatment in RA.

The Effect of Ketogenic Diet on Inflammatory Arthritis and Cardiovascular Health in Rheumatic Conditions: A Mini Review

The principle of ketogenic diet (KD) is restriction of carbohydrates to a maximum of 5-10% of the total daily caloric intake, aiming at shifting body metabolism toward ketone bodies. Different studies suggested promising results of KD to help patients to lose weight, to reduce insulin requirements in diabetes, to supplement cancer protocols, to treat neurological conditions and to optimize control of metabolic and cardiovascular diseases. However, literature about the anti-inflammatory properties of KD in rheumatic diseases is still limited. The beneficial effects of weight loss in patients with inflammatory arthritis can be explained by biomechanical and biochemical factors. Obesity is associated with macrophage activation and production of pro-inflammatory cytokines including TNF-α, IL-1b, and IL-6. The clinical effect of KD may be primarily attributed to improvement of insulin sensitivity. Insulin resistance is associated with an increase of TNF-α, IL-1α, IL-1β, IL-6, and leptin. Moreover, reduction of body's adipose tissue and weight loss account for part of the anti-inflammatory effects and for the impact of KD on cardiovascular health. In rheumatoid arthritis, fasting was shown to be effective in reducing disease symptoms, possibly through the production of β-hydroxybutyrate (BHB), the main ketone body. BHB may exert inhibitory effects also on IL-17 and intermittent fasting improved the clinical manifestations of psoriatic arthritis. In ankylosing spondylitis, current literature doesn't allow to draw conclusion about the effects of KD. Future prospective studies will be needed to elucidate the potential beneficial effects of KD on specific domains and clinical outcomes in patients with inflammatory arthritis.

Diet quality and disease activity in rheumatoid arthritis

Objective:This study examined associations between diet quality and disease activity in adults with rheumatoid arthritis (RA). Perceived stress was also compared to diet and disease activity. Methods: In a cross-sectional design, 50 adults with RA were recruited. The Arizona Food Frequency Questionnaire was used to measure dietary intake (four weeks) and diet quality scores were calculated with the Healthy Eating Index - 2015. Perceived stress was measured with the Perceived Stress Scale. Disease activity was measured with the Health Assessment Questionnaire-Disability Index and Pain Scale, erythrocyte sedimentation rate (ESR), high-sensitivity C-reactive protein, and Disease Activity Score Including 28 Joints-ESR. Results: Diet quality (56; SD ± 12) in participants was lower than the national mean (59). Age (p = 0.015) and gender (p = 0.003) were associated with higher diet quality. The belief that diet affects RA disease activity was reported by 44% of the participants, and these participants were significantly more likely to report dietary changes (p < 0.0001). Higher educational level (at least some college) was associated with this belief (B = -1.535, p = 0.023). Participants with lower diet quality also had significantly higher pain (B = -0.396, p = 0.022) and ESR scores (p = 0.019). Women were more likely to have higher HAQ-DI scores (B = 0.570, p = 0.001). Perceived stress was significantly associated with HAQ-DI and pain scores (B = 0.445, p = 0.001 and B = 0.289, p = 0.042, respectively). Medical cannabis was reportedly used by 8% of participants. Conclusion: In RA patients, lower diet quality may be associated with more pain and inflammation, and perceived stress may be associated with higher disability and disease activity.

The intervention of intestinal Wnt/β-catenin pathway alters inflammation and disease severity of CIA

Autoreactive T cell is one of the leading causes of immunological tolerance defects in the chronic inflammatory lesions of rheumatoid arthritis (RA). There have been several extracellular signals and intracellular pathways reported in regulating this process but largely remain unknown yet. In this study, we explored the roles of intestinal Wnt/β-catenin on disease severity during collagen-induced arthritis model (CIA), an animal model of RA. We first testified the activity pattern Wnt/β-catenin shifted by intragastric administration of LiCl and DKK-1 in the intestine by real-time PCR and WB analysis. The arthritis scores showing the disease severity in the DKK-1 group was significantly ameliorated compared with the control group at the late stage of the disease, while in the LiCl group, the scores were significantly elevated which was consistent with pathology score analysis of H&E staining. Next, ELISA was performed and showed that TNF-α and IL-17 in the LiCl group were significantly higher than that of the control group. IL-10 in the DKK-1 group was significantly higher than that in the LiCl-1 group and control group, P < 0.05. Flow cytometry of spleen T cells differentiation ratio showed that: Th1 from the DKK-1 and LiCl groups and Th17 from the LiCl group was significantly different from that of the blank model group, P < 0.05. Finally, we explored the effects of intestinal Wnt/β-catenin on T cell differentiation regulator ROR-γt and TCF1 and found that both transcription factors were up-regulated in the LiCl group. Together, these data suggested the pro-information role of Wnt/β-catenin pathway from the intestine in the CIA mouse, implying its use as a potential therapeutic target for the treatment of inflammatory diseases such as RA.

Causal association of monounsaturated fatty acids with rheumatoid arthritis but not osteoarthritis: A two-sample Mendelian randomization study

OBJECTIVES

Previous studies have indicated that dietary monounsaturated fatty acids (MUFAs) are associated with decreased risk of osteoarthritis (OA) and rheumatoid arthritis (RA). However, the causality of the observed associations is largely undetermined. We sought to ascertain the potential causal roles of two of the most common MUFAs, oleic acid and palmitoleic acid, in RA and OA risk using a two-sample Mendelian randomization approach.

METHODS

For the outcomes, we used summary-level data for RA (14 361 people with RA and 43 923 controls) and OA (10 083 people with OA and 40 425 controls) from two genome-wide association studies in European ancestry. For the exposures, five single-nucleotide polymorphisms associated with palmitoleic acid and one associated with oleic acid with genome-wide significance (P < 5 × 10^-8) were selected as instrumental variables. The causal effects were estimated using the inverse-variance weighted method with several sensitivity analyses.

RESULTS

For genetically predicted levels, an increase of one SD in palmitoleic acid (odds ratio, 0.24; 95% confidence interval, 0.10-0.59; P = 0.002) and oleic acid (odds ratio, 0.78; 95% confidence interval, 0.67-0.90; P < 0.001) was significantly associated with lower risk of RA. However, genetic predisposition to either of the two individual MUFAs was not associated with OA risk. Sensitivity analyses yielded similar results.

CONCLUSIONS

Our Mendelian randomization analyses suggest a causal relationship between higher genetically predicted MUFA levels and lower risks of RA. However, the causality between MUFAs and OA cannot be inferred from this study. Further research is required to unravel the role of MUFA supplementation in arthritis prevention.

Rheumatoid cachexia: the underappreciated role of myoblast, macrophage and fibroblast interplay in the skeletal muscle niche

Although rheumatoid arthritis affects 1% of the global population, the role of rheumatoid cachexia, which occurs in up to a third of patients, is relatively neglected as research focus, despite its significant contribution to decreased quality of life in patients. A better understanding of the cellular and molecular processes involved in rheumatoid cachexia, as well as its potential treatment, is dependent on elucidation of the intricate interactions of the cells involved, such as myoblasts, fibroblasts and macrophages. Persistent RA-associated inflammation results in a relative depletion of the capacity for regeneration and repair in the satellite cell niche. The repair that does proceed is suboptimal due to dysregulated communication from the other cellular role players in this multi-cellular environment. This includes the incomplete switch in macrophage phenotype resulting in a lingering pro-inflammatory state within the tissues, as well as fibroblast-associated dysregulation of the dynamic control of the extracellular matrix. Additional to this endogenous dysregulation, some treatment strategies for RA may exacerbate muscle wasting and no multi-cell investigation has been done in this context. This review summarizes the most recent literature characterising clinical RA cachexia and links these features to the roles of and complex communication between multiple cellular contributors in the muscle niche, highlighting the importance of a targeted approach to therapeutic intervention.

Dietary Quality Associated with Self-Reported Diabetes, Osteoarthritis, and Rheumatoid Arthritis among Younger and Older US Adults: A Cross-Sectional Study Using NHANES 2011-2016

Background: To date, few studies have compared the dietary quality of US adults with diabetes mellitus (DM), osteoarthritis (OA), and rheumatoid arthritis (RA) by age groups. Methods: This study used cross-sectional data from adult participants from National Health and Nutrition Examination Survey 2011–2016 to identify dietary quality measured by Healthy Eating Index (HEI)-2015 total and component scores and self-reported disease status for DM, OA, and RA. Associations between the disease status and HEI-2015 total/component scores among younger adults aged 20–59 years (n = 7988) and older adults aged 60 years and older (n = 3780) were examined using logistic regression models. These accounted for the complex survey design and were adjusted for self-reported disease status, sex, race/ethnicity, education levels, income status, weight status, physical activity levels, and smoking status. Results: Among younger adults, 7% had DM, 7% had OA, and 3% had RA. Among older adults, 20% had DM, 32% had OA, and 6% had RA. Moderate added sugar intake was associated with diabetes in all adults. Excess sodium intake was associated with DM among younger adults. Inadequate seafood and plant protein intake was associated with RA among younger adults, while a poor overall dietary pattern was associated with RA among older adults. Conclusions: The dietary quality of US adults varied by self-reported DM, OA, and RA status, and each varied by age group.

A Posteriori Dietary Patterns and Rheumatoid Arthritis Disease Activity: A Beneficial Role of Vegetable and Animal Unsaturated Fatty Acids

To our knowledge, no studies have investigated the relationship between a posteriori dietary patterns (DPs)-representing current dietary behavior-and disease activity in patients with rheumatoid arthritis (RA). We analyzed data from a recent Italian cross-sectional study including 365 RA patients (median age: 58.46 years, 78.63% females). Prevalent DPs were identified through principal component factor analysis on 33 nutrients. RA activity was measured according to the Disease Activity Score on 28 joints (DAS28) and the Simplified Disease Activity Index (SDAI). Single DPs were related to disease activity through linear and logistic regression models, adjusted for the remaining DPs and confounders. We identified five DPs (~80% variance explained). Among them, Vegetable unsaturated fatty acids (VUFA) and Animal unsaturated fatty acids (AUFA) DPs were inversely related to DAS28 in the overall analysis, and in the more severe or long-standing RA subgroups; the highest score reductions (VUFA: 0.81, AUFA: 0.71) were reached for the long-standing RA. The SDAI was inversely related with these DPs in subgroups only. This Italian study shows that scoring high on DPs based on unsaturated fats from either source provides independent beneficial effects of clinical relevance on RA disease activity, thus strengthening evidence on the topic.

Disease Activity, Functional Ability and Nutritional Status in Patients with Rheumatoid Arthritis: An Observational Study in Greece

AIM

The aim of the present pilot study was to assess differences in the nutritional status, Mediterranean diet (MD) adherence, and functional ability among patients with rheumatoid arthritis (RA), according to disease activity.

METHODS

A total of 48 patients with RA, outpatients of a hospital in Athens, Greece were recruited. Disease activity was evaluated with DAS28, functional status with the Health Assessment Questionnaire (HAQ), MD adherence with the MedDietScore and malnutrition with the patient-generated subjective global assessment (PG-SGA).

RESULTS

A relationship was noted between DAS28 and HAQ, indicating a reduced functional status with increased RA activity. Although MD adherence differed between DAS28 categories, no specific differences were noted in the PG-SGA or the MedDietScore in the post-hoc analyses. According to the PG-SGA, no need for nutritional intervention was noted among participants.

CONCLUSIONS

The origin of the participants might have reduced the differences between MD adherence and DAS28. In parallel, the PG-SGA does not appear sensitive in detecting muscle-related malnutrition among patients with RA.

Troublesome friends within us: the role of gut microbiota on rheumatoid arthritis etiopathogenesis and its clinical and therapeutic relevance

The role of gut microbiota on immune regulation and the development of autoimmune diseases such as rheumatoid arthritis (RA) is an emerging research topic. Multiple studies have demonstrated alterations on gut microbiota composition and/or function (referred to as dysbiosis) both in early and established RA patients. Still, research delineating the molecular mechanisms by which gut microorganisms induce the loss of immune tolerance or contribute to disease progression is scarce. Available data indicate that gut microbiota alterations are involved in RA autoimmune response by several mechanisms including the post-translational modification of host proteins, molecular mimicry between bacterial and host epitopes, activation of immune system and polarization toward inflammatory phenotypes, as well as induction of intestinal permeability. Therefore, in this review we analyze recent clinical and molecular evidence linking gut microbiota with the etiopathogenesis of RA. The potential of the gut microbiota as a diagnostic or severity biomarker is discussed, as well as the opportunity areas for the development of complementary therapeutic strategies based on the modulation of gut microbiota in the rheumatic patient.

Effect of Ramadan fasting on disease activity in patients with rheumatoid arthritis presenting in tertiary care hospital

BACKGROUND AND OBJECTIVE

Rheumatoid Arthritis (RA) is a common inflammatory disorder affected by various factors, including fasting. The objective of the study was to establish the effect of Ramadan fasting on DAS 28 in Rheumatoid Arthritis patients.

METHODS

In this observational cohort study done in department of rheumatology, Mayo hospital, Lahore, between May 2019 to July 2019, 240 patients were divided in fasting (n=120) and non-fasting cohort (n=120) based on their own choice. Mean DAS-28 scores before and after Ramadan was compared in both cohorts with appropriate statistical analyses.

RESULTS

Two hundred forty participants, (74 males, 166 females), were recruited. Baseline DAS of fasting group was significantly low (4.35±0.9) as compared to non-fasting group (5.07±0.91). Paired t-test showed statistically significant improvement in fasting and non-fasting groups in total and in both genders (p=0.000). Mean improvement in DAS was numerically greater and statistically significant (p=0.000) in non-fasting group (1.08±0.62) as compared to fasting ones (0.86±0.61). Post-Ramadan DAS was, however, significantly low in fasting group (3.49±0.9) versus non-fasting group (3.98±1.0) (p=0.000).

CONCLUSION

DAS 28 score decreased in both non-fasting as well as fasting patients of RA during the month of Ramadan. RA patients with moderate disease activity, who want to keep fast, can be allowed to do so without any fear of disease worsening.

The Influence of Socio-Demographic Factors, Lifestyle and Psychiatric Indicators on Adherence to Treatment of Patients with Rheumatoid Arthritis: A Cross-Sectional Study

Background and Objectives: Rheumatoid arthritis (RA) is a severe autoimmune disease characterized by chronic inflammation of the joints accompanied by the progressive deformation and destruction of cartilage and joint bones. This study aims to gain insight into the outcomes related to adherence in patients with rheumatoid arthritis. Predicting the medication adherence in RA patients is a key point to improve the treatment outcome. Materials and Methods: A number of 119 Romanian patients with RA were included and divided into two groups: first group included 79 patients treated with conventional therapy and second group included 40 patients treated with biologic therapy. A CQR-9 (compliance questionnaire rheumatology with nine items) and PDSQ (psychiatric diagnostic screening questionnaire) were performed to assess correlations between medication adherence, patient sociodemographic variables, 11 psychiatric scales (major depressive disorder, posttraumatic stress disorder, obsessive-compulsive disorder, panic disorder, psychosis, agoraphobia, social phobia, drug abuse/dependence, generalized anxiety disorder, somatization disorder, hypochondriasis) and lifestyle (bulimia, alcohol intake). Results: Whilst modelling factors associated with adherence, it was found that women and patients with higher education are more adherent. From the psychiatric indicators, only major depressive disorder and post-traumatic stress disorder were found to be positively correlated with therapeutic adherence. None of the assessed lifestyle factors influenced the adherence of RA patients. Conclusion: The knowledge of factors that impact on treatment adherence can be useful for clinicians to guide patient-centred care.

The Influence of Dietary Fatty Acids on Immune Responses

Diet-derived fatty acids (FAs) are essential sources of energy and fundamental structural components of cells. They also play important roles in the modulation of immune responses in health and disease. Saturated and unsaturated FAs influence the effector and regulatory functions of innate and adaptive immune cells by changing membrane composition and fluidity and by acting through specific receptors. Impaired balance of saturated/unsaturated FAs, as well as n-6/n-3 polyunsaturated FAs has significant consequences on immune system homeostasis, contributing to the development of many allergic, autoimmune, and metabolic diseases. In this paper, we discuss up-to-date knowledge and the clinical relevance of the influence of dietary FAs on the biology, homeostasis, and functions of epithelial cells, macrophages, dendritic cells, neutrophils, innate lymphoid cells, T cells and B cells. Additionally, we review the effects of dietary FAs on the pathogenesis of many diseases, including asthma, allergic rhinitis, food allergy, atopic dermatitis, rheumatoid arthritis, multiple sclerosis as well as type 1 and 2 diabetes.

Discussions of lifestyle habits as an integral part of care management: a cross-sectional cohort study in patients with established rheumatoid arthritis in Sweden

Objectives

The primary aim was to determine whether patients with RA recalled having discussions concerning lifestyle habits during their health-care visits. The secondary aim was to study the association between patients' reported lifestyle and their wish to discuss it.

Methods

A postal questionnaire sent to 1542 eligible patients from the Better Anti-Rheumatic Pharmacotherapy (BARFOT) study included questions on lifestyle habits (physical activity, diet, smoking and alcohol), on whether these were discussed during health-care visits and on whether there was an interest in such discussions.

Results

A total of 1061 patients (68%) responded [mean age 67 (s.d. 13) years, 73% women]. Half of the patients (49%) recalled discussions on physical activity, and 23% recalled discussions about diet. Those who reported health-enhancing levels of physical activity were more likely to discuss physical activity with their health professionals. Likewise, patients who reported having a non-traditional mixed diet were more likely to discuss diet. Smoking was discussed with 25% of the patients, more often with current smokers than with non-smokers (32 vs 17%; P < 0.001). Alcohol was discussed with 17% of the patients. Of those patients who reported having hazardous drinking habits, 77% had not discussed alcohol use with any health professional.

Conclusion

Discussions about lifestyle were recalled by half of the patients with established RA. There is a need for improvement, because lifestyle habits may affect the long-term outcome in a chronic disease, such as RA. Patient education concerning lifestyle habits should be an integral part of care management and an interactive process.

Diet, Microbiota, and Gut Permeability-The Unknown Triad in Rheumatoid Arthritis

Growing experimental and clinical evidence suggests that a chronic inflammatory response induced by gut dysbiosis can critically contribute to the development of rheumatic diseases, including rheumatoid arthritis (RA). Of interest, an adherence to a Mediterranean diet has been linked to a reduction in mortality and morbidity in patients with inflammatory diseases. Diet and intestinal microbiota are modifying factors that may influence intestinal barrier strength, functional integrity, and permeability regulation. Intestinal microbiota may play a crucial role in RA pathogenesis, but up to now no solid data has clarified a mechanistic relationship between gut microbiota and the development of RA. Nonetheless, microbiota composition in subjects with RA differs from that of controls and this altered microbiome can be partially restored after prescribing disease modifying antirheumatic drugs. High levels of Prevotella copri and similar species are correlated with low levels of microbiota previously associated with immune regulating properties. In addition, some nutrients can alter intestinal permeability and thereby influence the immune response without a known impact on the microbiota. However, critical questions remain to be elucidated, such as the way microbiome fluctuates in relation to diet, and how disease activity may be influenced by changes in diet, microbiota or diet-intestinal microbiota equilibrium.

In the absence of specific advice, what do patients eat and avoid? Results from a community based diet study in patients suffering from rheumatoid arthritis (RA) with a focus on potassium

Rheumatoid arthritis (RA) is a painful disabling difficult to treat disease. Clinicians and guidelines invariably focus on drugs. Diet is important but lacks robust data. We carried out a comprehensive analytical study in Indian (Asian) patients.

METHODS

141 consenting symptomatic chronic RA patients [mean age 46 years) center and 165 unrelated healthy control subjects (mean age 36 years) completed a a-priori validated food frequency questionnaire in a cross-sectional non-random design study under the supervision of a nutritionist. All patients were under standard rheumatology care. A 3 day retrospective recall record captured dietary data for all subjects. National Indian guidelines were adopted for diet analytics. Standard statistical analysis was carried out; significant p < 0.05.

RESULTS

Daily diet was found to be significantly deficient in calories and consumption of proteins, calcium and potassium when compared to healthy subjects. It was also inadequate for several nutrients when compacted to recommended daily allowance. The proportion of carbohydrates (65%), proteins (15%) and fat (25%) in daily diet was consistent with Indian standards (healthy). Women patients reported higher deficiency. 44% patients consumed vegetarian diet and showed lesser pain and better function compared to non-vegetarians (not significant). 44% patients reported dietary restriction; higher swollen joint counts in patients following any dietary restriction (p = 0.01) or Ayurveda (ancient Indian medicinal system) advise (p = 0.01) or consuming night shade vegetables (p = 0.002).

CONCLUSION

Dietary inadequacy and in particular for protein and potassium was identified in patients of RA. Any form of dietary restriction did not seem to improve RA. Specific dietary needs of RA patients and in particular impact of potassium deficiency needs further research.

The effect of brief versus individually tailored dietary advice on change in diet, lipids and blood pressure in patients with inflammatory joint disease

BACKGROUND

Patients with inflammatory joint diseases (IJD) have an increased risk of cardiovascular disease (CVD) compared to the general population. Nutritional advice has been shown to influence CVD risk factors. Our objective was to evaluate whether an individually tailored dietary counselling versus a brief standardised advice on heart-friendly diet had comparable effect on change in diet, lipids and blood pressure (BP) in patients with IJD.

METHODS

Thirty-one patients with IJD aged 40-80 years received a brief standardised advice (4 min) on heart-friendly diet by a physician. Sixteen of the patients were randomised to receive an additional, individually tailored, heart-friendly dietary counselling session (60 min) by a dietitian. Change in dietary habits, measured by a validated questionnaire (SmartDiet), lipids, BP and C-reactive protein (CRP) were assessed after 8 weeks of follow-up.

RESULTS

After 8 weeks, the average increase in SmartDiet score was 5.1 and 5.7 points in the diet group (DG) and the control group (CG), respectively ( p = 0.65). Low-density lipoprotein cholesterol (LDL-c) was reduced by 12.6% in the DG versus 2.4% in the CG ( p = 0.05). There were no significant differences between the two groups regarding change in BP, lipids or CRP.

CONCLUSION

Individually tailored dietary counselling resulted in more heart-friendly food choices in patients with IJD. However, the change in SmartDiet score was comparable for IJD patients receiving a brief nutritional advice and individually tailored heart-friendly dietary counselling. Further studies evaluating the longitudinal effects of dietary advice on CVD outcome in patients with IJD are warranted.

Relationship Between Fish Consumption and Disease Activity in Rheumatoid Arthritis

OBJECTIVE

To assess whether more frequent fish consumption is associated with lower rheumatoid arthritis (RA) disease activity scores among participants in an RA cohort.

METHODS

We conducted a cross-sectional analysis using baseline data from participants in the Evaluation of Subclinical Cardiovascular Disease and Predictors of Events in Rheumatoid Arthritis cohort study. Frequency of fish consumption was assessed by a baseline food frequency questionnaire assessing usual diet in the past year. Multivariable, total energy-adjusted linear regression models provided effect estimates and 95% confidence intervals (95% CIs) for frequency of fish consumption (i.e., never to <1 time/month, 1 time/month to <1 time/week, 1 time/week, and ≥2 times/week) on baseline Disease Activity Score in 28 joints (DAS28) using the C-reactive protein (CRP) level. We also estimated the difference in DAS28-CRP associated with increasing fish consumption by 1 serving per week.

RESULTS

Among 176 participants, the median DAS28-CRP score was 3.5 (interquartile range 2.9-4.3). In an adjusted linear regression model, subjects consuming fish ≥2 times/week had a significantly lower DAS28-CRP compared with subjects who ate fish never to <1 time/month (difference -0.49 [95% CI -0.97, -0.02]). For each additional serving of fish per week, DAS28-CRP was significantly reduced by 0.18 (95% CI -0.35, -0.004).

CONCLUSION

Our findings suggest that higher intake of fish may be associated with lower disease activity in RA patients.

Dietary Manipulations That Induce Ketosis Activate the HPA Axis in Male Rats and Mice: A Potential Role for Fibroblast Growth Factor-21

In response to an acute threat to homeostasis or well-being, the hypothalamic-pituitary-adrenocortical (HPA) axis is engaged. A major outcome of this HPA axis activation is the mobilization of stored energy, to fuel an appropriate behavioral and/or physiological response to the perceived threat. Importantly, the extent of HPA axis activity is thought to be modulated by an individual's nutritional environment. In this study, we report that nutritional manipulations signaling a relative depletion of dietary carbohydrates, thereby inducing nutritional ketosis, acutely and chronically activate the HPA axis. Male rats and mice maintained on a low-carbohydrate high-fat ketogenic diet (KD) exhibited canonical markers of chronic stress, including increased basal and stress-evoked plasma corticosterone, increased adrenal sensitivity to adrenocorticotropin hormone, increased stress-evoked c-Fos immunolabeling in the paraventricular nucleus of the hypothalamus, and thymic atrophy, an indicator of chronic glucocorticoid exposure. Moreover, acutely feeding medium-chain triglycerides (MCTs) to rapidly induce ketosis among chow-fed male rats and mice also acutely increased HPA axis activity. Lastly, and consistent with a growing literature that characterizes the hepatokine fibroblast growth factor-21 (FGF21) as both a marker of the ketotic state and as a key metabolic stress hormone, the HPA response to both KD and MCTs was significantly blunted among mice lacking FGF21. We conclude that dietary manipulations that induce ketosis lead to increased HPA axis tone, and that the hepatokine FGF21 may play an important role to facilitate this effect.

Diet and Rheumatoid Arthritis Symptoms: Survey Results From a Rheumatoid Arthritis Registry

OBJECTIVE

Patients with rheumatoid arthritis (RA) often ask whether specific foods, popularized as inflammatory or antiinflammatory, can improve or worsen their RA. Patients with RA took a survey on diet and RA symptoms, and the survey data were collected and analyzed.

METHODS

A dietary survey was mailed to 300 subjects in a single-center RA registry at a large academic center. Subjects were asked about their consumption of 20 foods and whether these foods make their RA symptoms better, worse, or unchanged. Semiannual registry data include demographics, medications, comorbidities, and disease activity scores. Fisher's exact test and Wilcoxon's rank sum tests evaluated associations between subject characteristics from the most recent registry assessment and changes in RA symptoms from specific foods.

RESULTS

Of the 217 subjects (72% response rate), 83% were female; the median RA duration was 17 years (interquartile range 9-27 years), and 58% were taking a biologic disease-modifying antirheumatic drug. Twenty-four percent of subjects reported that foods affect their RA symptoms, with 15% reporting improvement and 19% reporting worsening. Blueberries and spinach were the foods most often reported to improve RA symptoms, while soda with sugar and desserts were those most often reported to worsen RA symptoms. Younger age and noting that sleep, warm room temperature, and vitamin/mineral supplements improve RA were each associated with reporting that foods affect RA symptoms. Medication use, sex, body mass index, smoking, disease duration, disease activity scores, and self-reported RA flares were not associated with reporting that foods affect RA.

CONCLUSION

Nearly one-quarter of RA subjects with longstanding disease reported that diet had an effect on their RA symptoms.

Managing Rheumatoid Arthritis with Dietary Interventions

Self-help by means of dietary interventions can help in management of various disorders including rheumatoid arthritis (RA), a debilitating autoimmune disease. Dietary interventions necessitate a widespread appeal for both patients as well as clinicians due to factors including affordability, accessibility, and presence of scientific evidences that demonstrate substantial benefits in reducing disease symptoms such as pain, joint stiffness, swelling, tenderness and associated disability with disease progression. However, there is still an uncertainty among the community about the therapeutic benefits of dietary manipulations for RA. In the present review, we provide an account of different diets and their possible molecular mechanism of actions inducing observed therapeutic benefits for remission and management of RA. We further indicate food that can be a potential aggravating factor for the disease or may help in symptomatic relief. We thereafter summarize and thereby discuss various diets and food which help in reducing levels of inflammatory cytokines in RA patients that may play an effective role in management of RA following proper patient awareness. We thus would like to promote diet management as a tool that can both supplement and complement present treatment strategies for a better patient health and recovery.

Personalized diet and exercise recommendations in early rheumatoid arthritis: A feasibility trial

BACKGROUND

Physical activity and diet have a positive influence on disease activity and cardiovascular risk in patients with rheumatoid arthritis (RA).

OBJECTIVE

We tested the feasibility and effect of a brief individualized counselling intervention on physical activity levels and fitness, and dietary intake, compared with standard of care.

METHODS

Thirty patients with inflammatory arthritis (<1 year duration) were assigned to standard of care or the intervention, which consisted of individualized visits with a dietetic intern and physiotherapist at two time points, to review age-specific strategies on diet and exercise. Primary outcomes included anthropometric measurements (height, weight, waist and hip circumference), nutritional intake, physical activity (pedometer steps) and physical fitness. Disease activity measures and biochemical testing (blood pressure measurement, inflammatory markers, cholesterol profile and random glucose) were collected. The changes in these outcomes from baseline to 6 months were assessed using paired t-tests between groups.

RESULTS

Thirteen patients in the intervention group and 10 in the control group completed the study. There were non-significant trends in improvements in physical activity, low-density lipoprotein cholesterol level and nutritional intake (vitamin C, iron, fibre, vitamin A and folate) in the intervention group.

CONCLUSIONS

Poor enrolment and high dropout rates in this short-term study highlighted the difficulty of behavioural change. Those continuing in the study and who received the intervention demonstrated a non-significantly improved activity level and nutritional intake that may benefit long-term outcomes.

Cellular and molecular perspectives in rheumatoid arthritis

Synovial immunopathology in rheumatoid arthritis is complex involving both resident and infiltrating cells. The synovial tissue undergoes significant neovascularization, facilitating an influx of lymphocytes and monocytes that transform a typically acellular loose areolar membrane into an invasive tumour-like pannus. The microvasculature proliferates to form straight regularly-branching vessels; however, they are highly dysfunctional resulting in reduced oxygen supply and a hypoxic microenvironment. Autoantibodies such as rheumatoid factor and anti-citrullinated protein antibodies are found at an early stage, often before arthritis has developed, and they have been implicated in the pathogenesis of RA. Abnormal cellular metabolism and mitochondrial dysfunction thus ensue and, in turn, through the increased production of reactive oxygen species actively induce inflammation. Key pro-inflammatory cytokines, chemokines and growth factors and their signalling pathways, including nuclear factor κB, Janus kinase-signal transducer, are highly activated when immune cells are exposed to hypoxia in the inflamed rheumatoid joint show adaptive survival reactions by activating. This review attempts to highlight those aberrations in the innate and adaptive immune systems including the role of genetic and environmental factors, autoantibodies, cellular alterations, signalling pathways and metabolism that are implicated in the pathogenesis of RA and may therefore provide an opportunity for therapeutic intervention.

FlexPro MD, a Mixture of Krill Oil, Astaxanthin, and Hyaluronic Acid, Suppresses Lipopolysaccharide-Induced Inflammatory Cytokine Production Through Inhibition of NF-κB

FlexPro MD^® (FP-MD), a novel multi-ingredient dietary supplement formulation, has been demonstrated to relieve knee joint pain in humans. However, the mechanisms of action responsible for the activity of FP-MD have not been elucidated. In this study, we show the anti-inflammatory effects of FP-MD in RAW264.7 macrophage cells and mice challenged with lipopolysaccharide (LPS). FP-MD significantly inhibited the mRNA levels of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-1β. In contrast, it elevated the mRNA levels of anti-inflammatory cytokine IL-10 in LPS-stimulated RAW264.7 cells. FP-MD markedly reduced LPS-induced phosphorylation levels of nuclear factor-κB (NF-κB) p65 and inhibitor of κB-α (IκB-α). Importantly, the anti-inflammatory effects of FP-MD were demonstrated in mice with LPS-induced inflammatory arthritis in which FP-MD significantly reduced the expression levels of pro-inflammatory cytokines and inflammatory markers. Thus, this study suggests that FP-MD has anti-inflammatory effects by inhibiting NF-κB that may offer a molecular basis for its pain relief property.

Immunometabolism in early and late stages of rheumatoid arthritis

One of the fundamental traits of immune cells in rheumatoid arthritis (RA) is their ability to proliferate, a property shared with the joint-resident cells that form the synovial pannus. The building of biomass imposes high demands for energy and biosynthetic precursors, implicating metabolic control as a basic disease mechanism. During preclinical RA, when autoreactive T cells expand and immunological tolerance is broken, the main sites of disease are the secondary lymphoid tissues. Naive CD4⁺ T cells from patients with RA have a distinct metabolic signature, characterized by dampened glycolysis, low ATP levels and enhanced shunting of glucose into the pentose phosphate pathway. Equipped with high levels of NADPH and depleted of intracellular reactive oxygen species, such T cells hyperproliferate and acquire proinflammatory effector functions. During clinical RA, immune cells coexist with stromal cells in the acidic milieu of the inflamed joint. This microenvironment is rich in metabolic intermediates that are released into the extracellular space to shape cell-cell communication and the functional activity of tissue-resident cells. Increasing awareness of how metabolites regulate signalling pathways, guide post-translational modifications and condition the tissue microenvironment will help to connect environmental factors with the pathogenic behaviour of T cells in RA.