Serum levels of adiponectin and vitamin D correlate with activity of Rheumatoid Arthritis

Adipokines in Rheumatoid Arthritis: Emerging Biomarkers and Therapeutic Targets

Rheumatoid arthritis (RA) is a chronic inflammatory disease manifested by joint involvement, extra-articular manifestations, and general symptoms. Adipose tissue, previously perceived as an inert energy storage organ, has been recognised as a significant contributor to RA pathophysiology. Adipokines modulate immune responses, inflammation, and metabolic pathways in RA. Although most adipokines have a pro-inflammatory and aggravating effect on RA, some could counteract this pathological process. The coexistence of RA and sarcopenic obesity (SO) has gained attention due to its impact on disease severity and outcomes. Sarcopenic obesity further contributes to the inflammatory milieu and metabolic disturbances. Recent research has highlighted the intricate crosstalk between adipose tissue and skeletal muscle, suggesting potential interactions between these tissues in RA. This review summarizes the roles of adipokines in RA, particularly in inflammation, immune modulation, and joint destruction. In addition, it explores the emerging role of adipomyokines, specifically irisin and myostatin, in the pathogenesis of RA and their potential as therapeutic targets. We discuss the therapeutic implications of targeting adipokines and adipomyokines in RA management and highlight the challenges and future directions for research in this field.

Correlation of Rheumatoid arthritis disease severity with serum vitamin D levels

BACKGROUND AND AIM

Rheumatoid arthritis (RA) is an autoimmune disorder marked by characteristic inflammation of the small joints in addition to diverse systemic manifestations. Vitamin D has immunomodulatory properties, and its deficiency has a significant role in the clinical course of RA. The present research was conducted to study the correlation between serum vitamin D levels and disease activity scores in RA patients.

METHODS

A cross sectional study was carried out on a sample of 50 patients presenting with RA. Disease activity was measured using Modified Disease Activity Score (DAS) criteria. Estimation of serum Vitamin D levels were done using the electrochemiluminescence method and values less than 20 ng/ml were considered as deficiency. Vitamin D levels were then correlated with disease activity scores.

RESULTS

The Vitamin D deficiency was observed in 50% of the study population. Rheumatoid arthritis showed female preponderance in this study. Inflammatory markers such as C - reactive protein (CRP) levels and Erythrocyte Sedimentation Rate (ESR) did not differ with RA disease activity. More the number of large joints involved lesser were the vitamin D levels. There was an inverse correlation between Vitamin D levels and RA disease activity.

CONCLUSION

Vitamin D deficiency is significantly correlated with disease severity of RA. This study points to the importance of screening for deficit of vitamin D among RA patients and treat it as early as possible.

Vitamin D Deficiency in Saudi Patients With Rheumatoid Arthritis

Background Epidemiological studies indicate that vitamin D deficiency may increase the risk of developing autoimmune and chronic diseases such as rheumatoid arthritis (RA) and, therefore, is prevalent in patients with RA. Additionally, vitamin D insufficiency is associated with significant disease activity in patients with RA. This study aimed to assess the prevalence of vitamin D deficiency in Saudi patients with RA and determine whether there is an association between low vitamin D levels and RA disease activity. Methodology This cross-sectional retrospective study was conducted from October 2022 to November 2022 on patients who attended the rheumatology clinic at King Salman bin Abdulaziz Medical City, Medina, Saudi Arabia. Patients aged ≥18 years, diagnosed with RA, and not on vitamin D supplements were included. Demographic, clinical, and laboratory data were collected. Disease activity was measured using the disease activity score index of a 28-joint count using the erythrocyte sedimentation rate (DAS28-ESR). Results In total, 103 patients were included, with 79 patients being women (76.7%) and 24 being men (23.3%). The vitamin D level ranged from 5.13 to 94 ng/mL, with a median of 24. Of the studied cases, 42.7% had insufficient vitamin D levels, 22.3% had a deficiency, and 15.5% had severe deficiency. There were statistically significant correlations between the median vitamin D level and C-reactive protein (CRP), the number of swollen joints, and DAS. A lower median vitamin D level was detected among cases with positive CRP, swollen joints >5, and higher disease activity. Conclusions Patients with RA in Saudi Arabia were more likely to have low vitamin D levels. Moreover, vitamin D deficiency was linked to disease activity. Therefore, the measurement of vitamin D levels in patients with RA is essential, and vitamin D supplements might be important to improve disease outcomes and prognoses.

Adiponectin is negatively associated with disease activity and Sharp score in treatment-naïve Han Chinese rheumatoid arthritis patients

The association and potential role of the protein hormone adiponectin in autoimmune diseases causing musculoskeletal disorders, including rheumatoid arthritis (RA), are controversial. Conflicting results may arise from the influences of confounding factors linked to genetic backgrounds, disease stage, disease-modifying anti-rheumatic drugs and patients' metabolic characteristics. Here, we examined serum level of adiponectin and its relationship with disease activity score 28 with erythrocytes sedimentation rate (DAS28[ESR]) and Sharp score in a treatment-naïve Han Chinese RA population. This cross-sectional study enrolled 125 RA patients. Serum level of total adiponectin was assessed by enzyme-linked immunosorbent assay (ELISA). Other important clinical and laboratory parameters were collected from the hospital database. DAS28(ESR) was calculated according to the equation previously published. Sharp score was evaluated based on hands radiographs by an independent radiologist. The correlation between serum adiponectin level and DAS28(ESR) or the Sharp score was investigated by univariate and multivariable linear regression analyses, respectively. Multiple imputation by chained equations was used to account for missing data. Univariate analyses showed a significant positive correlation between DAS28(ESR) and age or C-reactive protein (CRP) (both p = 0.003), while serum adiponectin level was negatively correlated with DAS28(ESR) (p = 0.015). The negative correlation between adiponectin level and DAS28(ESR) remained true in multivariable analyses adjusted for confounders. In addition, the univariate analyses revealed positive correlations of Sharp score to disease duration (p < 0.001), CRP (p = 0.023) and ESR (p < 0.001). In the multivariable model adjusted for confounders, adiponectin was negatively correlated with Sharp score (p = 0.013). In this single-institution cross-sectional study, serum adiponectin level in treatment-naive RA patients is negatively correlated with DAS28(ESR) and the Sharp score after adjustment for prominent identified confounders. Serum adiponectin may be potentially useful for assessing disease activity and radiographic progression of RA.

No Causal Association Between Adiponectin and the Risk of Rheumatoid Arthritis: A Mendelian Randomization Study

Background: Accumulating evidence from observational studies suggested that circulating adiponectin levels are associated with the risk of rheumatoid arthritis (RA), but the causality remains unknown. We aimed to assess the causal relationship of adiponectin with RA risk. Methods: Based on summary statistics from large-scale genome-wide association studies (GWAS), we quantified the genetic correlation between adiponectin and RA. Then bidirectional Mendelian randomization (MR) analysis was performed to assess the causal relationship. Twenty single-nucleotide polymorphisms (SNPs) associated with adiponectin were selected as instrumental variables from a recent GWAS (n = 67,739). We applied theses SNPs to a large-scale GWAS for RA (14,361 cases and 43,923 controls) with replication using RA data from the FinnGen consortium (6,236 cases and 147,221 controls) and the UK Biobank (5,201 cases and 457,732 controls). The inverse-variance weighted (IVW) and multiple pleiotropy-robust methods were used for two-sample MR analyses. Results: Our analyses showed no significant genetic correlation between circulating adiponectin levels and RA [rG = 0.127, 95% confidence interval (CI): -0.012 to 0.266, P = 0.074]. In MR analyses, genetically predicted adiponectin levels were not significantly associated with the RA risk (odds ratio: 0.98, 95% CI: 0.88-1.09, P = 0.669). In the reverse direction analysis, there is little evidence supporting an association of genetic susceptibility to RA with adiponectin (β: 0.007, 95% CI: -0.003 to 0.018, P = 0.177). Replication analyses and sensitivity analyses using different models yielded consistent results. Conclusions: Our findings provided no evidence to support the causal effect of adiponectin levels on RA risk and of RA on circulating adiponectin levels.

Adiponectin Deregulation in Systemic Autoimmune Rheumatic Diseases

Deregulation of adiponectin is found in systemic autoimmune rheumatic diseases (SARDs). Its expression is downregulated by various inflammatory mediators, but paradoxically, elevated serum levels are present in SARDs with high inflammatory components, such as rheumatoid arthritis and systemic lupus erythematosus. Circulating adiponectin is positively associated with radiographic progression in rheumatoid arthritis as well as with cardiovascular risks and lupus nephritis in systemic lupus erythematosus. However, in SARDs with less prominent inflammation, such as systemic sclerosis, adiponectin levels are low and correlate negatively with disease activity. Regulators of adiponectin gene expression (PPAR-γ, Id3, ATF3, and SIRT1) and inflammatory cytokines (interleukin 6 and tumor necrosis factor α) are differentially expressed in SARDs and could therefore influence total adiponectin levels. In addition, anti-inflammatory therapy could also have an impact, as tocilizumab treatment is associated with increased serum adiponectin. However, anti-tumor necrosis factor α treatment does not seem to affect its levels. Our review provides an overview of studies on adiponectin levels in the bloodstream and other biological samples from SARD patients and presents some possible explanations why adiponectin is deregulated in the context of therapy and gene regulation.

A bioavailable form of curcumin, in combination with vitamin-D- and omega-3-enriched diet, modifies disease onset and outcomes in a murine model of collagen-induced arthritis

OBJECTIVE

Curcumin (CUR), vitamin D₃ (D3), and omega-3-fatty acids (O3FA) individually modulate inflammation and pain in arthritis. Although these supplements are widely used, their combinatorial effects have not been defined. In this study, we examined the effects of a D3 and O3FA (VO)-enriched diet in conjunction with a highly bioavailable form of CUR (Cureit/Acumin™) in a collagen-induced arthritis (CIA) murine model.

METHODS

Male DBA/1J mice were acclimatized to VO-enriched diet and challenged with bovine collagen II (CII). Bioavailable CUR was administered daily by oral gavage from the onset of CII challenge. Disease severity was determined by monitoring joint thickness and standardized clinical score. Cellular infiltration and cartilage degradation in the joints were assessed by histology, serum cytokines profiled by Meso Scale Discovery multiplex assay, and joint matrix metalloproteinases examined by western blots.

RESULTS

CUR by itself significantly decreased disease severity by ~ 60%. Administration of CUR in CIA mice taking a VO-enriched diet decreased disease severity by > 80% and maximally delayed disease onset and progression. Some of the disease-modifying effects was mediated by CUR alone, e.g., suppression of serum anti-collagen antibodies and decrease of cellular infiltration and MMP abundance in the joints of CIA mice. Although CUR alone suppressed inflammatory cytokines in serum of CIA mice, the combination of CUR and VO diet significantly enhanced the suppression (> 2-fold compared to CUR) of TNF, IFN-γ, and MCP-1, all known to be associated with RA pathogenesis.

CONCLUSION

This study provides proof-of-concept that the combination of bioavailable CUR, vitamin D₃, and O3FA substantially delays the development and severity of CIA. These findings provide a rationale for systematically evaluating these widely available supplements in individuals at risk for developing future RA.

The Effect of Vitamin D Supplementation on Rheumatoid Arthritis Patients: A Systematic Review and Meta-Analysis

Objective Observational studies have shown that vitamin D levels are inversely related to rheumatoid arthritis activity, yet evidence from population interventions remains inconsistent. Methods: The PubMed, Cochrane Library, Embase, CNKI, VIP, and Wanfang databases were searched for studies published before June 2020. Information was collected about the pain visual analog scale (VAS), Disease Activity Score 28 (DAS28), serum vitamin D level, tender joint count (TJC), swollen joint count (SJC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and parathyroid hormone (PTH) research data. Results: Six studies (n = 438) were included in the meta-analysis. Vitamin D supplementation resulted in a significant improvement in the DAS28 (weighted mean difference (WMD) = -0.41, 95% CI (-0.59, -0.23), P < 0.001), ESR (WMD = -3.40, 95% CI (-6.62, -0.18), P = 0.04) and TJC (WMD = -1.44, 95% CI (-2.74, -0.14), P = 0.03) but not in other outcomes. According to the subgroup analyses, VAS and serum vitamin D were improved in the European ethnic subgroups. TJC and serum vitamin D were improved in the Asian ethnic subgroups. TJC and serum vitamin D were improved in the duration ≤ 12 w subgroups, and the VAS and DAS28 in the duration > 12 w subgroup were different from those of the control group. With a vitamin D dose ≤50,000 IU, only serum vitamin D and TJC improved, and with a vitamin D dose> 50,000 IU, the VAS and DAS28 improved. Conclusions: Compared with placebo control interventions, vitamin D supplementation seemed to be an effective intervention for patients with rheumatoid arthritis. Different doses of vitamin D and durations of intervention produce different effects.

Serum adiponectin levels are associated with presence of carotid plaque in women with systemic lupus erythematosus

BACKGROUND AND AIM

Systemic lupus erythematosus (SLE) is associated with accelerated atherogenesis. Traditional risk factors do not seem to fully explain this process in patients with SLE and no other imaging/serum biomarkers have so far improved risk stratification. Here, we focused on the role of adiponectin in women with SLE.

METHODS AND RESULTS

This is a sub-analysis of a validated cohort enrolling eighty females (age 18-65 years) affected by SLE. Patient underwent a single blood sampling and carotid echography. Serum adipocytokines (i.e. leptin, resistin and adiponectin) were assessed by enzyme-linked immunosorbent assay (ELISA). Patients with a carotid plaque (n = 23) were older, with longer duration of the disease, chronic use of corticosteroids, and immunosuppressive therapies. As expected, patients with a carotid plaque had increased vascular risk and high serum levels of inflammatory biomarkers, total and LDL cholesterol and adiponectin. Significant positive correlation between serum adiponectin and presence of a carotid plaque was found independently of patient age, SCORE Risk Charts, duration of disease, and SLE treatments.

CONCLUSIONS

These results indicate that high serum adiponectin is associated with accelerated carotid atherosclerosis in SLE young women and it might be useful to improve vascular risk stratification in this patient setting.

Impact of season on the association between vitamin D levels at diagnosis and one-year remission in early Rheumatoid Arthritis

The study evaluates associations between serum vitamin D metabolites at diagnosis and one-year remission, in early diagnosed rheumatoid arthritis(RA). The CIMESTRA-cohort comprised 160 newly diagnosed RA patients, treated aiming at remission. Vitamin D supplementation was recommended according to national guidelines. D_total(25OHD₂ + 25OHD₃) was dichotomized at 50 nmol/L, 1,25(OH)₂D was categorized in tertiles. Primary outcome was remission(DAS28-CRP ≤ 2.6) after one year. Associations were evaluated using logistic regression, further adjusted for pre-specified potential confounders: Age, sex, symptom-duration before diagnosis, DAS28-CRP and season of diagnosis. Results are presented as Odds Ratios(OR) with 95% Confidence Intervals(95%CIs). In univariate analyses, neither D_total nor 1,25(OH)₂D were associated with remission. In adjusted analyses, low D_total was associated with higher odds for remission; OR 2.6, 95%CI (1.1; 5.9) p = 0.03, with season impacting results the most. One-year remission was lower in patients with diagnosis established at winter. In conclusion, low D_total at diagnosis was associated with increased probability of achieving one-year remission in early RA when adjusting for covariates. Diagnosis in winter was associated with lower odds for one-year remission. Results suggest that season act as a contextual factor potentially confounding associations between vitamin D and RA disease-course. The finding of low D_total being associated with higher one-year remission remains speculative.

Vitamin D and autoimmune disease

Vitamin D as a part of the endocrine system is an important component in the interaction between the kidney, bone, parathyroid hormone, and the intestine, which maintains extracellular calcium level within normal limits, in order to keep the vital physiologic process and skeletal integrity. Vitamin D is also associated with hypertension, muscular function, immunity, and ability to encounter infection, autoimmune disease, and cancer. The role of vitamin D in immunity is a feedback reaction of paracrine to eliminate inflammation or to influence CD4 T-cell differentiation and or to increase the function of T suppressor cell or combination between both. The active form of vitamin D produces and maintains self immunologic tolerance, some studies show that 1,25(OH)2D inhibits induction of disease in autoimmune encephalomyelitis, thyroiditis, type-1 diabetes mellitus, inflammatory bowel disease (IBD), systemic lupus erythematosus, and collagen-induced arthritis and Lyme arthritis.