Serum level of adiponectin is a surrogate independent biomarker of radiographic disease progression in early rheumatoid arthritis: results from the ESPOIR cohort

Adiponectin as a predictor of mortality and readmission in patients with community-acquired pneumonia: a prospective cohort study

Background

Adiponectin is secreted by adipocytes and is inversely associated with obesity. Given the association between low body mass index (BMI) and higher mortality risk after community-acquired pneumonia (CAP), we hypothesized that high adiponectin levels are associated with a higher risk of adverse clinical outcomes in patients with CAP.

Methods

In a prospective cohort study of 502 patients hospitalized with CAP, adiponectin was measured in serum at admission. The associations between adiponectin and clinical outcomes were estimated with logistic regression analyses adjusted for age, sex, and measures of obesity (BMI, waist circumference or body fat percentage).

Results

Adiponectin was associated with higher 90-day mortality for each 1 μg/mL increase [OR 1.02, 95% CI (1.00, 1.04), p = 0.048] independent of age and sex. Likewise, adiponectin was associated with a higher risk of 90-day readmission for each 1 μg/mL increase [OR 1.02, 95% CI (1.01, 1.04), p = 0.007] independent of age and sex. The association between adiponectin and 90-day mortality disappeared, while the association with 90-day readmission remained after adjusting for adiposity.

Conclusion

Adiponectin was positively associated with mortality and readmission. The association with mortality depended on low body fat, whereas the association with readmission risk was independent of obesity.

A new serum biochemical marker of synovium turnover predicts radiographic progression in patients with early arthritis

OBJECTIVE

To investigate whether serum Col 3-4, a new biochemical marker of synovial tissue turnover, was associated with progression of joint damage in patients with early arthritis.

METHODS

A total of 788 early arthritis patients (<6 months of symptoms, 82% diagnosis of RA, 18% undifferentiated arthritis) from the prospective ESPOIR study were investigated. Progression was defined as an increase of 1 or 5 unit(s) in radiographic van der Heijde modified Sharp score between baseline and 1 or 5 years, respectively. Associations between baseline Col 3-4 and progression were assessed by logistic regression.

RESULTS

Each standard deviation increase of baseline Col 3-4 levels was associated with an increased 5-yr total damage progression with an odds ratio (OR, 95% CI) of 1.51 (1.21, 1.88), which remained significant when DAS28, C-reactive protein and anti-citrullinated protein antibodies positivity were included in the model [OR (95% CI): 1.34 (1.01, 1.76)]. Further adjustment for bone erosion did not modify the association. Patients with both Col 3-4 in the highest quintile and bone erosion had a >2-fold higher risk of progression [OR (95% CI): 7.16 (2.31, 22)] than patients with either high Col 3-4 [2.91 (1.79, 4.73)] or bone erosion [2.36 (2.38, 3.70)] alone. Similar associations were observed for prediction of 12 months progression.

CONCLUSIONS

Increased serum Col 3-4 is associated with a higher risk of structural progression, independently of major risk factors. Col 3-4 may be useful in association with bone erosion to identify patients with early arthritis at higher risk.

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.

Adipokines and risk of rheumatoid arthritis: A two-sample multivariable Mendelian randomisation study

Adiponectin, leptin, and resistin are thought to be involved in the pathogenesis of rheumatoid arthritis (RA). However, the causal relationship between these adipokines and the risk for RA is unclear. We performed a range of two-sample Mendelian randomisation (MR) analyses to assess the causal effect of circulating adiponectin, leptin, and resistin on RA risk in European and East Asian individuals. Different sets of adiponectin-, leptin-, and resistin-related genetic variants were used as instruments for genetically determined adipokine levels. As body mass index (BMI) is a risk factor for RA and affects adipokine levels, multivariable MR was used to calculate the causal effect of each adipokine on RA risk taking BMI into account. Several MR analyses revealed no evidence of a causal relationship between circulating adiponectin, leptin, or resistin levels and RA risk in either Europeans or East Asians. Similarly, multivariable MR did not provide evidence of any causal effect of adiponectin, leptin, or resistin on RA risk when taking BMI into account. This MR study shows for the first time that genetically determined levels of adiponectin, leptin, or resistin do not have a direct causal effect on the risk of developing RA after adjustment for BMI.

The Influence of Adipokines on Radiographic Damage in Inflammatory Rheumatic Diseases

Inflammatory rheumatic diseases (IRDs) are complex immune-mediated diseases that are characterized by chronic inflammation of the joints. Rheumatoid arthritis (RA) and spondyloarthritis (SpA), including axial SpA (ax SpA) and psoriatic arthritis (PsA), are the most common forms of IRD. Both RA and ax SpA are characterized by a chronic course with progressive structural modifications, namely, cartilage damage and bone erosions in RA and osteoproliferative changes with spinal ossifications in ax SpA. The adipose tissue is involved in the pathophysiology of IRDs via the release of several proteins, namely, adipokines. Several adipokines with pro-inflammatory effects have been identified, such as leptin, adiponectin, visfatin and resistin. In this review, we discuss the role that adipokines may play in the structural modifications of the peripheral joints and/or axial skeleton. In RA, the role of leptin in structural damage remains controversial, while adiponectin and its high-molecular-weight isoform are known to have an influence on the development of bone erosions and radiographic progression. Resistin also appears to be a potent detrimental adipokine for the joints in RA. In ax SpA, visfatin seems to be an attractive candidate for radiographic progression, while leptin and adiponectin have negative effects on radiographic progression.

Rheumatoid arthritis and nutritional profile: A study in Brazilian females

BACKGROUND

Patients with rheumatoid arthritis (RA) may have nutritional impairment. In RA, muscle loss is associated with an increase in fat tissue, and the patients may not have body mass index (BMI) alterations.

AIM

To study the nutritional status in a sample of patients with RA in Brazil through mini nutritional assessment (MNA) and electric bioimpedance and its relationship to BMI, functionality, disease activity, and treatment.

METHODS

Seventy-one RA females were included. Chart review was used to obtain epidemiological, clinical, and treatment data. Patients answered the MNA and were submitted to electrical bioimpedance and anthropometric measurements. Disease activity was assessed through simple disease activity index (SDAI), clinical disease activity index (CDAI), and function, through health assessment questionnaire (HAQ).

RESULTS

According to MNA, 23 (32.4%) patients were at risk for malnutrition and 1 (1.4%) was malnourished. MNA were associated with disease activity and function impairment (SDAI P = .02; CDAI P = .02, and HAQ P = .002) but not with used medications. According to BMI, 76% were overweight or obese. An increased percentage of body fat was found in 98.7% and a lower percentage of lean mass in 95.7%. Disease activity and function were not associated with the percentage of body fat of any used medications, with a lower percentage of body fat in those using abatacept (P = .01).

CONCLUSION

Almost one-third of patients had nutritional impairment according to MNA which was associated with disease activity and loss of function. Almost the whole sample had an increased percentage of fat mass and a diminished percentage of muscle mass that could not be linked with disease activity, function or used medications.

Adiponectin Is a Component of the Inflammatory Cascade in Rheumatoid Arthritis

Adiponectin is a secretory protein of adipocytes that plays an important role in pathological processes by participation in modulating the immune and inflammatory responses. The pro-inflammatory effect of adiponectin is observed in rheumatoid arthritis (RA). In this study, we examined adiponectin plasma levels and the expression of adiponectin in bone marrow tissue samples, synovium samples, and infrapatellar fat pad samples from patients with osteoarthritis (OA) and RA. Additionally we examined the expression of adiponectin receptors AdipoR1 and AdipoR2 in synovium samples and infrapatellar fat pad samples from patients with OA and RA. We also assessed the correlations between adiponectin plasma concentrations, adiponectin expression in bone marrow, synovium, infrapatellar fat pad, and plasma levels of selected cytokines. We found increased expression of adiponectin in synovium samples and infrapatellar fat pad samples from patients with RA as compared to patients with OA. There were no statistically significant differences of adiponectin plasma levels and adiponectin expression in bone marrow tissue samples between OA and RA patients. There were no differences in the expression of AdipoR1 and AdipoR2 at the mRNA level in synovial tissue and the infrapatellar fat pad between RA and OA patients. However, in immunohistochemical analysis in samples of the synovial membrane from RA patients, we observed very strong expression of adiponectin in intima cells, macrophages, and subintimal fibroblasts, such as synoviocytes, vs. strong expression in OA samples. Very strong expression of adiponectin was also noted in adipocytes of Hoffa’s fat pad of RA patients. Expression of AdipoR1 was stronger in RA tissue samples, while AdipoR2 expression was very similar in both RA and OA samples. Our results showed increased adiponectin expression in the synovial membrane and Hoffa’s pad in RA patients compared to that of OA patients. However, there were no differences in plasma adiponectin concentrations and its expression in bone marrow. The results suggest that adiponectin is a component of the inflammatory cascade that is present in RA. Pro-inflammatory factors enhance the expression of adiponectin, especially in joint tissues—the synovial membrane and Hoffa’s fat pad. In turn, adiponectin also increases the expression of further pro-inflammatory mediators.

Emerging role of leptin in joint inflammation and destruction

Rheumatoid arthritis (RA) is an autoimmune disease characterized by tumor-like hyperplasia and inflammation of the synovium, which causes synovial cell invasion into the bone and cartilage. In RA pathogenesis, various molecules in effector cells (i.e., immune cells and mesenchymal cells) are dysregulated by genetic and environmental factors. Consistent with the early stages of RA, these pathogenic cells cooperate and activate each other directly by cell-to-cell contact or indirectly via humoral factors. Recently, growing evidence has revealed essential role of adipokines, which are multifunctional signal transduction molecules, in the immune system. In this review, we summarize the current understanding of the cross-talk between leptin, one of the most well-known and best-characterized adipokines, and osteoimmunology. Furthermore, we discuss the contribution of leptin to the pathogenesis of RA and its potential mechanisms.

Bone Loss and Radiographic Damage Profile in Rheumatoid Arthritis Moroccan Patients

Background

Rheumatoid arthritis (RA) is a known cause of joint destruction and systemic bone loss. In this study, we aimed to evaluate the bone damage and bone loss profiles of established RA patients.

Methods

We designed a cross-sectional study on a cohort of established RA patients. The bone evaluation was performed by obtaining standard X-ray images of hands and feet combined with bone mineral density (BMD) measurements. Radiographic joint damage was calculated by the modified total Sharp /van der Heijde score (mTSS). BMD was obtained by performing dual energy X-ray absorptiometry of the lumbar spine and femoral neck. Data on age, smoking, alcoholism, steroid prescription, body mass index (BMI), disease duration, disease activity, and functional disability were collected.

Results

A total of 93 RA patients were recruited. Their mean age was 51.59±12.38 years, with a mean disease duration of 12.07±9.19 years. A total of 36.6% of patients had osteoporosis, and the mean mTSS was 70.33±48.93. Both hip (P=0.0005) and lumbar BMD (P=0.0005) were correlated with mTSS. Backward regression analyses determined that bone damage was associated with high titers of rheumatoid factor, low lumbar BMD, and low BMI. General bone loss was associated with gender, steroid dose, steroid duration, menopause, and BMI.

Conclusions

Bone damage was associated with low BMI and axial bone loss in our RA population.

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.

Adipokines, Cardiovascular Risk, and Therapeutic Management in Obesity and Psoriatic Arthritis

Psoriatic arthritis is a chronic inflammatory disease with skin and joint pathology as the dominant characteristics. Scientific evidence supports its systemic nature and relevant relationship with obesity, metabolic syndrome, and associated conditions. Metabolic syndrome and obesity share common signaling pathways with joint inflammation, reinforcing the idea that adipose tissue is a major contributor to disease development and severity. The adipose tissue is not a mere energy store but also an endocrine organ participating in the immune response. In the search for the best therapeutic strategy for a patient, we should appraise the adipose tissue as an endocrine and immune organ responsible for mild chronic inflammation. Today, our challenge is not only to achieve disease remission but to control the associated comorbidities as well. In light of the high prevalence of obesity in psoriatic arthritis patients and the importance of the adipose tissue in the development of chronic inflammation, we aimed to identify the most relevant articles in this regard published in English until June 2020 using the PubMed database. Search terms included psoriatic arthritis, in combination with metabolic syndrome, obesity, adipokines, cardiovascular disease, and treatment. This review summarizes the current evidence regarding the role of adipose tissue as an adipokine-secreting endocrine organ, discussing its influence on disease development and severity, and ultimately in meeting successful disease management.

Predictors of radiographic erosion and joint space narrowing progression in patients with early rheumatoid arthritis: a cohort study

Background

Radiographic damage in rheumatoid arthritis (RA) includes erosions and joint space narrowing (JSN). Different mechanisms may underlie their development. The objective of this study was to evaluate predictors of these entities separately.

Methods

Consecutive early RA patients (symptom duration ≤12 months) from a defined area (Malmö, Sweden) recruited during 1995–2005 were investigated. Radiographs of hands and feet were scored by a trained reader according to the modified Sharp-van der Heijde score. Fat mass and lean mass distribution were measured at baseline using dual energy x-ray absorptiometry. Potential predictors of erosion and JSN progression from inclusion to the 5-year follow-up were evaluated.

Results

Two hundred and thirty-three patients were included. Radiographs at baseline and 5 years were available for 162 patients. The median (interquartile) progression of erosion and JSN scores were 4 (0–8) and 8 (1–16), respectively. Rheumatoid factor (RF) was a robust significant predictor of both erosion and JSN score progression. In adjusted analyses, anti-CCP antibodies predicted erosions while the erythrocyte sedimentation rate was predictive of both outcomes. Smoking and high baseline disease activity (DAS28 > 5.1) predicted progression of erosions. Baseline erosion score was associated with progression of both erosion and JSN progression, while baseline JSN score was predictive only of the progression of JSN. Overweight/obesity (BMI ≥ 25 kg/m²) was a significant negative predictor of JSN score progression (β = − 0.14, p = 0.018, adjusted for RF, age, baseline JSN score) also when additionally adjusting for ever smoking (p = 0.041). Among female patients, this effect was observed in those of estimated post-menopausal age (> 51 years), but not in younger women. The truncal to peripheral fat ratio was associated with less JSN score progression in women, but not in men.

Conclusions

Overweight RA patients had less JSN progression, independent of smoking status. This effect was seen in particular among older women (mainly post-menopausal), but not younger. Truncal fat was associated with less JSN progression in female patients. Smoking predicted erosion progression, and erosions may precede JSN. BMI and fat distribution may influence cartilage damage in early RA and might be related to hormonal factors.

Mini-Review: The Contribution of Adipokines to Joint Inflammation in Inflammatory Rheumatic Diseases

Inflammatory rheumatic diseases (IRD) are complex disorders characterized by chronic inflammation of the joints and related skeletal structures. The most common forms of IRD are rheumatoid arthritis (RA) and spondyloarthritis (SpA), including axial SpA (axSpA) and psoriatic arthritis (PsA). Obesity is a frequent comorbidity in RA and PsA, and to a lesser extend in axial SpA. The association between obesity and IRD may be explained by the release from fat tissue of several bioactive proteins, namely adipokines. Adipokines are involved in the regulation of various processes such as lipid or glucose metabolism, but also inflammation. Adipokines are interrelated with the immune system, with both innate and adaptive immune cell connections. Several adipokines with pro-inflammatory effects have been identified such as leptin, visfatin or resistin. Conversely, adiponectin and more specifically its low molecular weight isoform, is considered to have antiinflammatory properties. In this review, we discuss the contribution of adipokines to the joint inflammation of IRD, the relation they have with immune pathways of these diseases, their links with the structural impact on peripheral joints and/or axial skeleton, and also the influence they may have on the cardiometabolic risk of IRD.

Role of Adiponectin in the Pathogenesis of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic chronic inflammatory autoimmune joint disease, characterized by progressive articular damage and joint dysfunction. One of the symptoms of this disease is persistent inflammatory infiltration of the synovial membrane, the principle site of inflammation in RA. In the affected conditions, the cells of the synovial membrane, fibroblast-like synoviocytes and macrophage-like synovial cells, produce enzymes degrading cartilage and underlining bone tissue, as well as cytokines increasing the infiltration of immune cells. In patients with RA, higher levels of adiponectin are measured in the serum and synovial fluid. Adiponectin, a secretory product that is mainly white adipose tissue, is a multifunctional protein with dual anti-inflammatory and pro-inflammatory properties. Several studies underline the fact that adiponectin can play an important pro-inflammatory role in the pathophysiology of RA via stimulating the secretion of inflammatory mediators. This narrative review is devoted to the presentation of recent knowledge on the role played by one of the adipokines produced by adipose tissue—adiponectin—in the pathogenesis of rheumatoid arthritis.

Association Between Adiponectin and Clinical Manifestations in Rheumatoid Arthritis

Adiponectin (APN) belongs to adipokines. Previous studies showed contradictory results that have both proinflammatory and anti-inflammatory effects in rheumatoid arthritis (RA). We set out to detect the levels of APN and the correlations between APN and the clinical manifestations in RA patients. Sera of 60 newly diagnosed patients with RA and 29 age- and gender-matched healthy subjects were collected. Clinical parameters, including C-reactive protein (CRP), erythrocyte sedimentation rate, rheumatoid factor (RF), antibodies to cyclic citrullinated peptide, disease activity score 28, and bone erosion conditions, were collected. The serum levels of total APN and high-molecular-weight APN (HMW-APN) were detected by enzyme-linked immunosorbent assay. As a result, total APN and HMW-APN levels were all lower in patients with RA compared with healthy controls. The levels of APN and HMW-APN were all positively correlated with CRP levels. There was also positive correlation between HMW-APN levels and RF levels. Moreover, patients with higher disease activities had higher HMW-APN levels; patients with more severe synovial thickening had higher APN and HMW-APN levels. Therefore, APN, especially HMW-APN, may play a regulatory role in RA.

Association of adipokines with rheumatic disease activity indexes and periodontal disease in patients with early rheumatoid arthritis and their first-degree relatives

OBJECTIVE

To evaluate the adipokine levels in early rheumatoid arthritis (eRA) and first-degree relatives (FDR) of patients with RA and establish their association with rheumatic disease activity and periodontal variables.

METHOD

A cross-sectional study with eRA patients, FDR and a healthy population. Adipokine levels, clinical, joint radiological indexes and periodontal variables were evaluated. A descriptive, bivariate analysis was performed based on the adipokine levels by χ² , Fisher's test and Mann-Whitney U test. A logistic regression was made for associations.

RESULTS

High leptin levels were associated with the diagnosis of eRA (odds ratio [OR] = 2.79; 95% CI 1.54-5.07). Early rheumatoid arthritis with high adiponectin levels was less likely to have Multidimensional Health Assessment Questionnaire score >3, body mass index (BMI) >25 and Routine Assessment of Patient Index Data 3 score >12 (OR = 0.16; 95% CI 0.03-0.72). Early rheumatoid arthritis was more likely to present high leptin and interleukin (IL)6 levels with low adiponectin simultaneously (OR = 5.03; 95% CI 1.05-24.0). High leptin levels were associated with the FDR adjusted for IgG2 Porphyromonas gingivalis, swollen joints, P gingivalis and low IL6 (OR = 2.57; 95% CI 1.14-5.95).

CONCLUSION

High adipokine levels in eRA may modulate the disease activity. Having more than 1 adipokine at high serum levels is associated with increased disability, disease activity and BMI, indicating that RA is controlled by adiponectin levels in the early stages of the disease. High leptin levels, presence of P gingivalis and swollen joints may be the factors associated with the development of RA in FDR.

Nicotinamide phosphoribosyltransferase secreted from microglia via exosome during ischemic injury

Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme of the salvage pathway of nicotinamide adenine dinucleotide synthesis. NAMPT can also be secreted and functions as a cytokine. We have previously shown that in the brain, NAMPT expression and secretion can be induced in microglia upon neuroinflammation and injury. Yet the mechanism for NAMPT secretion remains unclear. Here we show that NAMPT can be actively secreted from microglia upon the treatment of ischemia-like injury - oxygen-glucose deprivation and recovery (OGD/R). We confirmed that classical ER-Golgi pathway is not involved in NAMPT secretion. NAMPT secretion was further enhanced by ATP, and the secretion was mediated by P2X₇ receptor and by intracellular Ca²⁺ . Importantly, we found that phospholipase D inhibitor, n-butanol, phospholipase D siRNA, and wortmannin significantly decreased OGD/R-induced and ATP-enhanced release of NAMPT in microglia. After excluding the mechanisms of involving secretory autophagy, endosomes, and secretory lysosome, we have concluded that microglial NAMPT is secreted mainly via exosome. Immune-electron microscopy identifies NAMPT in extracellular vesicles with the size and morphology characteristic of exosome. With the vesicles harvested by ultra-centrifugation, exosomal NAMPT is further confirmed by Western blotting analysis. Intriguingly, the amount of NAMPT relative to exosomal protein markers remains unchanged upon the treatment of OGD/R, suggesting a constant load of exosomal NAMPT in microglia. Taken together, we have identified NAMPT is actively secreted via exosome from microglia during neuroinflammation of ischemic injury.

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

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which numerous cells and mediators affect inflammatory conditions and disease severity. To compare the serum levels of adiponectin, vitamin D, copper, and zinc in patients with RA and to investigate the relationship between these parameters and RA severity. Ninety patients with RA and 30 healthy controls participated in this cross-sectional case-control study between November 2016 and April 2017; according to the ACR/EULAR criteria for RA. Serum levels of adiponectin were determined by ELISA; copper and zinc by colorimetric spectrophotometry; and vitamin D by HPLC. Kruskal-Wallis and Spearman tests were performed using SPSS software and data were depicted by GraphPad Prism software. Compared with healthy controls, the serum level of adiponectin was significantly increased, whereas vitamin D was significantly decreased in patients with RA. Adiponectin and vitamin D levels were inversely correlated in RA subgroups (P < 0.001, r = - 0.410). Adiponectin and vitamin D correlated with RA severity. Furthermore, no significant difference was found in copper and zinc levels between RA groups and controls. The definitive roles of adiponectin, vitamin D, copper, and zinc are not completely determined in RA development. Based on disease activity, these parameters can modulate inflammatory conditions, thus they have the potential to be used as promising therapeutic biomarkers to follow up the severity of disease, as well as the progression and treatment success in patients with RA.

Associations between Adipokines in Arthritic Disease and Implications for Obesity

Secretion from adipose tissue of adipokines or adipocytokines, comprising of bioactive peptides or proteins, immune molecules and inflammatory mediators, exert critical roles in inflammatory arthritis and obesity. This review considers the evidence generated over the last decade regarding the effects of several adipokines including leptin, adiponectin, visfatin, resistin, chemerin and apelin, in cartilage and bone homeostasis in the pathogenesis of rheumatoid arthritis and osteoarthritis, which has important implications for obesity.

Adiponectin profile at baseline is correlated to progression and severity of multiple sclerosis

BACKGROUND AND PURPOSE

Adiponectin is a cytokine linking energy metabolism and immune system. After being assembled, adiponectin circulates as oligomers of different molecular weight, i.e. low, medium and high (HMW) molecular weight. These have the most potent biological effects. Multiple sclerosis (MS) is an autoimmune disease of the human central nervous system. The aim of this study was to characterize the expression levels of both total adiponectin and its oligomerization state in the serum from 99 patients with MS at baseline (i.e. not influenced by therapies). We also investigated the potential relationships between adiponectin and disease progression and severity.

METHODS

Adiponectin was quantified and visualized by enzyme-linked immunosorbent assay, western blotting and fast protein liquid chromatography. During the follow-up (3.6 ± 2.20 years), the patients were evaluated using total annualized relapse rate and Expanded Disability Status Scale score.

RESULTS

Total adiponectin is statistically higher in patients with MS compared with matched controls (12.18 vs. 10.02 μg/mL, P = 0.001). Interestingly, the adiponectin oligomerization state is altered in MS, with an increase of HMW oligomers. In addition, patients with MS with higher levels of adiponectin at baseline have significantly higher risk of progression and severity (Multiple Sclerosis Severity Score, 3.84 vs. 2.44, P = 0.001). No statistical difference in adiponectin expression was found between active and inactive patients with MS and among the different forms of disease.

CONCLUSIONS

This study demonstrated that adiponectin and its HMW oligomers are greatly involved in MS autoimmune disorder representing a potential biomarker to predict worse MS prognosis and severity. Further studies are required to clarify the molecular mechanisms underlying the properties of adiponectin and HMW oligomers in MS.

Serum adiponectin as a predictor of laboratory response to anti-TNF-α therapy in rheumatoid arthritis

Introduction

While adiponectin is typically viewed as an anti-inflammatory mediator, such an activity of adiponectin in rheumatoid arthritis (RA) is not so obvious. In the present study we examined whether serum levels of adiponectin reflect the clinical phenotype of RA patients and/or correlate with severity of the disease and the response to anti-TNF-α therapy.

Material and methods

Twenty-one female RA patients qualified to receive anti-TNF-α treatment were prospectively assessed before and after 12 weeks of therapy. Patients underwent full clinical and biochemical assessment. Disease activity was assessed by the Modified Disease Activity Scores (DAS28). Serum concentrations of adiponectin were measured with an immunoassay. The individuals were divided into two subgroups according to whether their baseline serum adiponectin was below or above the median value. The subgroups did not differ in basic demographic, anthropometric, and clinical parameters.

Results

Anti-TNF-α treatment resulted in a significant clinical (DAS28) improvement in patients from both subgroups, but no significant differences between basal and post-treatment serum adiponectin concentrations were observed. However, patients with higher baseline adiponectin experienced a significant and more pronounced improvement in laboratory parameters of inflammation (ESR, CRP, neutrophil count, neutrophil-to-lymphocyte ratio).

Conclusions

It is possible that adiponectin exerts systemic anti-inflammatory effects independently of the local activity of RA.

Inflammation, obesity and rheumatic disease: common mechanistic links. A narrative review

Obesity represents a rising global health concern, linked to significant social, psychological and physical burden to the individual affected, people around them and the society as a whole. Obesity has been described as a low-grade inflammatory condition, associated with increased production of pro-inflammatory mediators like tumor necrosis factor alpha or interleukin 6 and altered expression of adipokines. Adipokines, mainly produced by adipose tissue, have mixed pro- and anti-inflammatory properties. Obesity rarely exists on its own; instead, it tends to coexist with (often multiple) other comorbidities, including metabolic, cardiovascular, and rheumatic and musculoskeletal diseases (RMDs). In the case of RMDs, evidence is rapidly accumulating on common mechanistic pathways implicated in the inflammatory states seen between RMDs and obesity. Although there remain unanswered questions on the exact mechanisms of inflammation that link obesity to RMDs, what is becoming increasingly known is the association between obesity and adverse clinical outcomes in RMDs. This narrative review discusses insights into mechanisms of inflammation linking obesity and RMDs and evidence on the impact of obesity on treatment response and important disease outcomes. We highlight the importance of targeting obesity, a common and modifiable comorbidity, as part of the routine care of people with RMDs.

NAMPT: A pleiotropic modulator of monocytes and macrophages

Nicotinamide phosphoribosyltransferase (NAMPT) is the bottleneck enzyme of the NAD salvage pathway and thereby is a controller of intracellular NAD concentrations. It has been long known that the same enzyme can be secreted by a number of cell types and acts as a cytokine, although its receptor is at present unknown. Investigational compounds have been developed that target the enzymatic activity as well as the extracellular action (i.e. neutralizing antibodies). The present contribution reviews the evidence that links intracellular and extracellular NAMPT to myeloid biology, for example governing monocyte/macrophage differentiation, polarization and migration. Furthermore, it reviews the evidence that links this protein to some disorders in which myeloid cells have a prominent role (acute infarct, inflammatory bowel disease, acute lung injury and rheumatoid arthritis) and the data showing that inhibition of the enzymatic activity or the neutralization of the cytokine is beneficial in preclinical animal models.

Presence of hepatitis B virus in synovium and its clinical significance in rheumatoid arthritis

Background

Previous studies have revealed that hepatitis B virus (HBV) infection may be related to rheumatoid arthritis (RA), but there are no studies on the presence of HBV antigens or nucleic acid in synovium from patients with RA with HBV infection. In the present study, we investigated the presence of HBV in the synovium and its clinical significance in RA.

Methods

Fifty-seven consecutive patients with active RA (Disease Activity Score 28-joint assessment based on C-reactive protein ≥ 2.6) and available synovial tissue who had completed 1 year of follow-up were recruited from a prospective cohort. The patients were divided into chronic HBV infection (CHB, n = 11) and non-CHB groups according to baseline HBV infection status. Clinical data were collected at baseline and at 1-, 3-, 6-, and 12-month follow-up. Radiographic changes of hand/wrist at baseline and month 12 were assessed with the Sharp/van der Heijde-modified Sharp score (mTSS). HBV in synovium was determined by immunohistochemical staining for hepatitis B virus surface antigen and hepatitis B virus core antigen (HBcAg) and by nested PCR for the HBV S gene.

Results

HBcAg was found in the synovium of patients with RA with CHB (7 of 11, 64%), which was confirmed by PCR for the HBV S gene. Compared with the non-CHB group, more CD68-positive macrophages, CD20-positive B cells, and CD15-positive neutrophils infiltrated the synovium in the CHB group (all p <  0.05). There were smaller improvements from baseline in most disease activity indicators mainly at month 12, and a significantly higher percentage of CHB patients experienced 1-year radiographic progression (ΔmTSS ≥ 0.5 unit/yr, 64% vs. 26%, p = 0.024). Multivariate logistic regression analysis showed that CHB status (OR 14.230, 95% CI 2.213–95.388; p = 0.006) and the density of synovial CD68-positive macrophages (OR 1.002, 95% CI 1.001–1.003; p = 0.003) were independently associated with 1-year radiographic progression.

Conclusions

The presence of HBV in RA synovium may be involved in the pathogenesis of local lesions and exacerbate disease progression in RA.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1623-y) contains supplementary material, which is available to authorized users.

Smoking, body mass index, disease activity, and the risk of rapid radiographic progression in patients with early rheumatoid arthritis

BACKGROUND

Identification of risk factors for rapid joint destruction in early rheumatoid arthritis (RA) can be helpful for optimizing treatment, and improving our understanding of destructive arthritis and its mechanisms. The objective of this study was to investigate the relationship between early RA patient characteristics and subsequent rapid radiographic progression (RRP).

METHODS

An inception cohort of patients with early RA (symptom duration < 12 months), recruited during 1995-2005 from a defined area (Malmö, Sweden), was investigated. Radiographs of the hands and feet were scored in chronological order according to the modified Sharp-van der Heijde score (SHS), by a trained reader. RRP was defined as an increase of ≥ 5 points in SHS per year.

RESULTS

Two hundred and thirty-three patients were included. Radiographs were available from 216 patients at baseline, 206 patients at 1 year, and 171 patients at 5 years. Thirty-six patients (22%) had RRP up to 5 years. In logistic regression models, rheumatoid factor (RF) and anti-cyclic citrullinated peptides (anti-CCP), and increased erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) at baseline, predicted RRP over 5 years. Patients identified as overweight or obese had a significantly reduced risk of RRP up to 5 years (odds ratio (OR) 0.26; 95% confidence interval (CI) 0.11-0.63; adjusted for RF, baseline erosions, and ESR). Similar point estimates were obtained when stratifying for antibody status, and in models adjusted for smoking. A history of ever smoking was associated with a significantly increased risk of RRP up to 5 years, independent of body mass index (BMI) (OR 3.17; 95% CI 1.22-8.28; adjusted for BMI). At the 1-year follow-up, erosive changes, Disease Activity Score of 28 joints, Health Assessment Questionnaire, swollen joint count, and patient's global assessment of disease activity and pain were also significantly associated with RRP up to 5 years.

CONCLUSIONS

A history of smoking, presence of RF and/or anti-CCP and early erosions, high initial disease activity and active disease at 1 year, all increase the risk of RRP. Patients with a high BMI may have a reduced risk of severe joint damage. This pattern was not explained by differences in disease activity or antibody status. The results of this study suggest independent effects of smoking and BMI on the risk of RRP.

Adiponectin aggravates bone erosion by promoting osteopontin production in synovial tissue of rheumatoid arthritis

Background

We have previously reported that adiponectin (AD), an adipokine that is secreted by adipocytes, correlates well with progressive bone erosion in rheumatoid arthritis (RA). The exact mechanism of AD in promoting joint destruction remains unclear. Osteopontin (OPN) is required for osteoclast recruitment. We hypothesized that AD exacerbates bone erosion by inducing OPN expression in synovial tissue. This study aimed to evaluate a novel role for AD in RA.

Methods

The serum levels of AD and OPN were determined in 38 patients with RA, 40 patients with osteoarthritis (OA), and 20 healthy controls using enzyme-linked immunosorbent assay (ELISA). AD and OPN production were measured by double immunofluorescence in RA and OA synovial tissue. Quantitative real-time PCR and immunofluorescence were used to evaluate the mRNA and protein expression levels of OPN in RA synovial fibroblasts (RASFs) and OA synovial fibroblasts after pre-incubation with AD, respectively. Migration of the RAW264.7 osteoclast precursor cell line was assessed using the Transwell migration assay and co-culture system. Bone destruction and osteoclastogenesis were assessed by immunohistochemical staining, microcomputed tomography and tartrate-resistant acid phosphatase (TRAP) staining in AD-treated collagen-induced arthritis (CIA) mice with or without OPN silencing. The expression levels of OPN and integrin α_vβ₃ in the ankle joint tissues of the mice were examined by double immunofluorescence.

Results

Our results indicated that the AD and OPN expression levels increased noticeably and were associated with each other in the RA serum. The AD distribution was coincident with that of OPN in the RA synovial tissue. AD stimulation of RASFs increased OPN production in a dose-dependent manner. AD-treated RASFs promoted RAW264.7 cell migration, and the effect was blocked with a specific antibody against OPN. Silencing of OPN using lentiviral-OPN short hairpin RNA reduced the number of TRAP-positive osteoclasts and the extent of bone erosion in the AD-treated CIA mice. When bound to integrin α_vβ₃, OPN functions as a mediator of AD and osteoclasts.

Conclusions

Our study provides new evidence of AD involvement in bone erosion. AD induces the expression of OPN, which recruits osteoclasts and initiates bone erosion. These data highlight AD as a novel target for RA treatment.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1526-y) contains supplementary material, which is available to authorized users.

High serum adiponectin is associated with anemia development in chronic kidney disease: The results from the KNOW-CKD study

BACKGROUND

Adiponectin is an adipokine secreted by adipocytes. A low adiponectin level is a significant risk factor of diabetes mellitus and cardiovascular disease. Recent studies have shown that adiponectin is negatively associated with hematopoiesis and predicts the development of anemia in the general population. In chronic kidney disease (CKD) patients, circulating adiponectin level is paradoxically elevated and the role of adiponectin is complex. Therefore, we evaluated the relationship between adiponectin and anemia in these patients.

METHODS

This prospective longitudinal study included 2113 patients from the KNOW-CKD study (KoreaN cohort study for Outcome in patients With CKD), after excluding 125 without data on adiponectin levels. Hemoglobin levels were measured yearly during a mean follow-up period of 23.7 months. Anemia was defined as hemoglobin levels of <13.0 and 12.0 g/dL for men and women, respectively.

RESULTS

Mean patient age was 53.6 ± 12.2 years, and 1289 (61%) were men. The mean estimated glomerular filtration rate (eGFR) was 50.4 ± 30.2 mL min^-1 1.73 m^-2. Serum adiponectin level was inversely associated with body mass index, eGFR, log-transformed C-reactive protein, and positively with Charlson comorbidity index, urine protein to creatinine ratio, and high density lipoprotein cholesterol. In addition, serum adiponectin level was also negatively correlated with hemoglobin level and reticulocyte production index in both men and women. In multivariable linear regression analysis after adjustment of multiple confounders, adiponectin was negatively associated with hemoglobin (men, β = -0.219, P < .001; women, β = -0.09, P = .025). Among 1227 patients without anemia at baseline, 307 newly developed anemia during the follow-up period. In multivariable Cox regression analysis after adjustment of confounders, high adiponectin level was significantly associated with an increased risk of incident anemia (per 1 µg/mL increase, hazard ratio, 1.02; 95% confidence interval 1.01-1.04; P = .001).

CONCLUSIONS

A high serum adiponectin level is independently associated with a low hemoglobin level and predicts the development of anemia in patients with CKD. These findings reveal the potential role of adiponectin in CKD-related anemia.

Adiposity Measures and Plasma Adipokines in Females with Rheumatoid and Osteoarthritis

The objective of this study was to examine the relationship between adipokines and adiposity in individuals with rheumatoid and osteoarthritis in the Atlantic PATH cohort. Using a nested case-control analysis, participants in the Atlantic PATH cohort with rheumatoid or osteoarthritis were matched for measures of adiposity with participants without a history of arthritis. Both measured and self-reported data were used to examine disease status, adiposity, and lifestyle factors. Immunoassays were used to measure plasma markers. BMI was positively correlated with percentage body fat, fat mass index (FMI), and a change in BMI from 18 years of age in all 3 groups. There were no statistical differences between levels of plasma adipokines; adiponectin levels were 6.6, 7.9, and 8.2 μg/ml, leptin levels were 10.3, 13.7, and 11.5 ng/ml, and resistin levels were 10.0, 12.1, and 10.8 ng/ml in participants without arthritis, with rheumatoid arthritis, and with osteoarthritis, respectively. Those with higher levels of adiponectin were more likely to have osteoarthritis (but not rheumatoid arthritis). No association was found between arthritis types and leptin or resistin. This study demonstrates differences in measures of adiposity and adipokines in specific types of arthritis and highlights the need for more research targeting specific adipokines during arthritic disease progression.

Obesity is a strong predictor of worse clinical outcomes and treatment responses in early rheumatoid arthritis: results from the SWEFOT trial

Objectives

The aim of this paper was to analyse the impact of obesity, in addition to known predictors, on disease outcome in early rheumatoid arthritis (RA).

Methods

Body mass index (BMI) was available in 260 patients from the Swedish pharmacotherapy trial (SWEFOT). Differences in disease activity (DAS28), functional impairment (HAQ), pain (Visual Analogue Scale, VAS-pain) and radiographic damage were evaluated over 24 months between BMI categories (obese BMI >30, n=43; overweight BMI=25–29.9, n=74; normal BMI <25, n=143) using non-parametric testing. Predictors of European League Against Rheumatism non-remission (DAS28 ≥2.6) at 24 months of follow-up were evaluated using binary univariate and multivariate logistic regression.

Results

Obesity at baseline was associated with worse continuous-scale clinical outcomes over 24 months (DAS28, HAQ and VAS-pain at last visit: obese vs normal: p<0.001; obese vs overweight: p<0.05). Furthermore, obese patients compared with non-obese patients had significantly greater odds of non-remission at 24 months (adjusted OR (aOR) 5.2; 95% CI 1.8 to 15.2). Other independent predictors were female sex (aOR 2.6; 95% CI 1.1 to 5.8), current smoking (aOR 2.6; 95% CI 1.1 to 6.3) and HAQ (per-unit increase, aOR 1.9; 95% CI 1.1 to 3.4). The pattern was similar among seropositive and seronegative patients; and in the subgroups of methotrexate responders and patients randomised at 3 months to add-on of sulfasalazine+hydroxychloroquine, although not significant with add-on of infliximab. Obesity had no independent association to radiographic progression.

Conclusions

In this early RA trial reflecting today’s standard treatment, obesity, in addition to sex, smoking and functional impairment strongly lowered the chance of attaining good clinical outcomes, including remission, today’s treatment goal. This highlights the importance of considering lifestyle modification as one of the cornerstones of RA care.

Trial registration number

NCT00764725; Post-results. WHO database at the Karolinska University Hospital: CT20080004.

Baseline adiponectin and leptin levels in predicting an increased risk of disease activity in rheumatoid arthritis: A meta-analysis and systematic review

To determine the pathogenic role of adipokines, such as adiponectin and leptin, in rheumatoid arthritis (RA) by investigating whether serum levels of these adipokines correlated with disease activity in RA patients. Medline, Cochrane, EMBASE and Google Scholar were searched for studies published until 5 November 2015 reporting serum levels of leptin and adiponectin and measures of disease activity including DAS scores and radiographic progression scores (such as total change in SHS scores and number of erosions). Secondary outcomes included pain scores, functional status and health questionnaires. Only randomized controlled trials, cohort studies, or two-armed prospective or retrospective studies were included. A χ²-based test of homogeneity was performed using Cochran's Q statistic and I². A total of 917 predominantly female participants (average age range, 39-56 years) from six prospective cohort studies were included for assessment. A fixed-effects analysis was applied for leptin levels due to lack of heterogeneity among the studies (Q = 4.4364; I²=32.38). A random-effects analysis was applied to serum levels of adiponectin because of significant heterogeneity between studies (Q = 4.444, I²=77.50%). Serum leptin levels were higher in RA patients with high disease activity (pooled SMD: 0.53, 95% CI: 0.24-0.82); however, serum adiponectin levels did not correlate with RA disease activity (pooled OR: 1.38, 95% CI: 0.77-2.47). The meta-analysis provides an additional factor to determine high disease activity index in RA, that is, serum leptin levels, which can be of benefit when choosing treatment strategies.

Vitamin D attenuates inflammation, fatty infiltration, and cartilage loss in the knee of hyperlipidemic microswine

Background

Osteoarthritis (OA) of the knee joint is a degenerative process resulting in cartilage loss. Recent evidence suggests that OA is not merely a disease of cartilage but a disease of the entire knee joint and that inflammation may play an important role. OA has been associated with vitamin D deficiency. Vitamin D as an immunomodulator and anti-inflammatory agent may attenuate inflammation in the knee. The aim of this study was to assess the anti-inflammatory effect of vitamin D on inflammation in the knee.

Methods

This study was conducted with 13 microswine on a high cholesterol diet categorized into three groups of vitamin D-deficient, vitamin D-sufficient, and vitamin D supplementation. After 1 year, microswine were killed, and their knee joint tissues were harvested. Histological and immunofluorescence studies were carried out on the tissue specimens to evaluate the effect of vitamin D status.

Results

Histological and immunofluorescence studies of the knee joint tissues showed (1) increased inflammation in the knee joint tissues, (2) fatty infiltration in quadriceps muscle, patellar tendon, and collateral ligaments, and (3) chondrocyte clustering in the vitamin D-deficient and vitamin D-sufficient groups compared with the vitamin D supplementation group. Architectural distortion of the quadriceps muscle, patellar tendon, and collateral ligaments was also seen in the areas of inflammatory foci and fatty infiltration in the vitamin D-deficient group.

Conclusions

Decreased inflammation and fatty infiltration in the vitamin D supplementation group suggest the potential role of vitamin D in attenuating inflammation and fatty infiltration as well as in protecting the architecture of the tissue in the knee joint.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1099-6) contains supplementary material, which is available to authorized users.

Role of leptin in the progression of psoriatic, rheumatoid and osteoarthritis

Leptin, an adipokine responsible for body weight regulation, may be involved in pathological processes related to inflammation in joint disorders including rheumatoid arthritis (RA), osteoarthritis, and psoriatic arthritis (PsA). These arthropathies have been associated with a wide range of systemic and inflammatory conditions including cardiovascular disease, obesity, and metabolic syndrome. As a potent mediator of immune responses, leptin has been found in some studies to play a role in these disorders. Furthermore, current potent biologic treatments effectively used in PsA including ustekinumab (an interleukin 12/23 blocker) and adalimumab (a tumor necrosis factor-alpha blocker also used in RA) have been found to increase leptin receptor expression in human macrophages. This literature review aims to further investigate the role leptin may play in the disease activity of these arthropathies.

Smoking Functions as a Negative Regulator of IGF1 and Impairs Adipokine Network in Patients with Rheumatoid Arthritis

Objectives. Smoking is pathogenic for rheumatoid arthritis (RA) being tightly connected to the genetic and serological risk factors for this disease. This study aims to understand connections between cigarette smoking and serum levels of IGF1 and adipokines in RA. Methods. Serum levels of IGF1 and adipokines leptin, adiponectin, resistin, and visfatin were measured in two independent cohorts of RA patients from Gothenburg (n = 350) and Leiden (n = 193). An association of these parameters with smoking was tested in a direct comparison and proved by bivariate correlation analysis. The obtained associations were further tested in multivariate regression models where the confounders (age, gender, disease duration, and BMI) were controlled. Results. The smokers had significantly lower serum levels of IGF1, adiponectin, and leptin compared to never smokers. In regression analysis, smoking and low leptin, but not adiponectin, were associated and predicted low IGF1. Additionally, high disease activity and high BMI increased the probability of low leptin. Conclusions. The study indicates cigarette smoking as an important cause of a relative IGF1 and leptin deficiency in RA patients. This novel association between smoking and hypoleptinemia may be of importance for long-term prognosis of RA and for prediction of comorbidities.

Serum leptin and serum leptin/serum leptin receptor ratio imbalance in obese rheumatoid arthritis patients positive for anti-cyclic citrullinated peptide antibodies

Introduction

Leptin has a prominent role in the development and maintenance of acute and chronic inflammatory states such as rheumatoid arthritis (RA) and obesity. Nevertheless, the association of serum leptin (sLep) and soluble leptin receptor (sLepR) in RA pathogenesis has not been clarified. The purpose of this study was to evaluate the association of sLep, sLepR and leptin production indexes such as sLep/fat mass ratio with clinical activity and biomarkers and anti-cyclic citrullinated peptide (anti-CCP) antibodies in RA compared with body mass index (BMI) matched control subjects.

Methods

We included 64 RA patients and 66 controls matched for age, gender and BMI. Subjects were evaluated for BMI, fat mass distribution, sLep, sLepR, sLep/fat mass ratio and sLepR/fat mass ratio. Patients were evaluated for clinical activity and anti-CCP antibodies.

Results

We found two or three fold increased sLep levels, sLep/sLepR ratio and sLep/fat mass ratio in obese anti-CCP positive RA patients vs. controls. Partial correlations showed that anti-CCP antibodies were correlated with sLep/fat mass ratio (partial r = 0.347, P = 0.033) after adjustment for age, subcutaneous adipose tissue and fat mass.

Conclusions

In preobese and obese RA patients there is and increased production of sLep according to anti-CCP positivity. This phenomenon suggests there is an additive effect of chronic inflammation resulting from RA and obesity in which leptin favors the humoral response against citrullinated proteins. In summary, the data observed in our study suggests sLep could be a surrogate marker of chronicity and humoral immunity in RA in the presence of obesity.

Association of Body Mass Index Categories with Disease Activity and Radiographic Joint Damage in Rheumatoid Arthritis: A Systematic Review and Metaanalysis

OBJECTIVE

Obesity and overweight are increasing conditions. Adipose tissue with proinflammatory properties could be involved in rheumatoid arthritis (RA) activity and radiographic progression. This study aims to investigate the influence of overweight and obesity on RA activity and severity.

METHODS

We conducted a systematic review and metaanalysis to assess the association of body mass index (BMI) categories with the Disease Activity Score in 28 joints (DAS28), functional disability [Health Assessment Questionnaire (HAQ)], and radiographic joint damage in patients with RA. We searched Medline through PubMed, EMBASE, and the Cochrane Database of Systematic Reviews for all studies assessing DAS28, HAQ, or/and radiographic damage according to predefined BMI groups.

RESULTS

Among the 737 citations retrieved, 58 articles met the inclusion criteria and 7 were included in the metaanalysis. DAS28 was higher in obese (BMI > 30 kg/m(2)) than non-obese (BMI ≤ 30 kg/m(2)) patients (mean difference 0.14, 95% CI 0.01-0.27, p = 0.04, I(2) = 0%). HAQ score was also higher among obese patients (mean difference 0.10, 95% CI 0.01-0.19, p = 0.03, I(2) = 0%). Radiographic joint damage was negatively associated with obesity (standardized mean difference -0.15, 95% CI -0.29 to -0.02, p = 0.03, I(2) = 38%).

CONCLUSION

Obesity in RA is associated with increased DAS28 and HAQ score and with lower radiographic joint damage. These associations mainly result from an increase of subjective components of the DAS28 (total joint count and global health assessment) in obese patients. Conflicting results were reported concerning inflammation markers (C-reactive protein and erythrocyte sedimentation rate).

Continuously elevated serum matrix metalloproteinase-3 for 3 ~ 6 months predict one-year radiographic progression in rheumatoid arthritis: a prospective cohort study

INTRODUCTION

Core disease activity indicators of rheumatoid arthritis (RA) have been found to be limited in predicting joint destruction progression. Matrix metalloproteinase (MMP) 3 plays an essential role in joint destruction and was found elevated in some remission patients. We aimed to monitor dynamic core disease activity indicators and serum MMP-3 for one year and evaluate their value for predicting radiographic progression.

METHODS

Patients with active RA (Simplified disease activity index > 3.3) were treated according to the treat-to-target strategy. Serum MMP-3 was detected by enzyme-linked immunosorbent assay and clinical data were collected simultaneously at 0, 1st, 3rd, 6th and 12th month. X-ray assessment of hand/wrist was repeated at baseline and the 12th month and a change of total Sharp score > 0.5 units was defined as radiographic progression.

RESULTS

Fifty-six patients completed one year follow-up and 29 % showed radiographic progression. Although not significantly different at baseline, serum MMP-3 and all core disease activity indicators, except for erythrocyte sedimentation rate, at the 12th month were significantly higher in the progressive group than in the non-progressive group. Among sixteen progressive patients, 69 % achieved the therapeutic target and 56 % had continuous elevated serum MMP-3, 38 % had continuous elevated serum MMP-3 and normal C-reactive protein (CRP) at the 6th month. Log-rank tests and repeated measures analysis revealed a significant difference in dynamic serum MMP-3 between progressive and non-progressive patients. Receiver operating characteristic curve and univariate logistic regression analysis showed that elevated serum MMP-3 at 0, 1st, 3rd and 6th months, compared with CRP at the 1st month, were significant predictors for one-year radiographic progression (MMP-3 odds ratio (OR):10.500 ~ 27.000, all P < 0.05; CRP: OR = 7.400, P = 0.011).

CONCLUSIONS

Our data showed that continuously elevated serum MMP-3 for 3 ~ 6 months predicted one-year radiographic progression which implied that monitoring of dynamic serum MMP-3 combined with core disease activity indicators may be more helpful for predicting radiographic progression and treatment decision in RA.

Multifaceted roles of adiponectin in rheumatoid arthritis

Adiponectin is a circulating hormone with pleiotropic functions in lipid and glucose metabolism secreted by adipocytes. It plays a beneficial role in cardiovascular functions and metabolic complications. Recently, growing researches have elucidated that increased adiponectin plasma levels correlate with severity of rheumatoid arthritis (RA) and it is speculative that adiponectin may link to RA. The association of adiponectin with potential inflammatory functions in RA has raised significant interests in exploring this adipokine as a target for RA-diagnostic and therapeutic applications. Despite significant advances in understanding adiponectin functions and signaling mechanisms, its roles in RA remain multifaceted and subject to controversy. This review highlights the evidences linking adiponectin to either anti-inflammatory or pro-inflammatory action in RA. The results of this review may provide important insight into adiponectin in the development of RA.

Osteoprotegerin and tumor necrosis factor-related apoptosis-inducing ligand as prognostic factors in rheumatoid arthritis: results from the ESPOIR cohort

Introduction

We previously reported that low ratio of osteoprotegerin (OPG) to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was associated with Disease Activity Score in 28 joints (DAS28) remission at 6 months in patients with early rheumatoid arthritis (RA). Here, we aimed to evaluate the value of baseline OPG/TRAIL ratio in predicting clinical and radiological outcomes in patients with early RA in the ESPOIR cohort.

Methods

OPG and TRAIL serum concentrations were assessed in the ESPOIR cohort patients. Patients with definite RA were included in this study. Patients were excluded if they had high erosion score at baseline (>90^th percentile) or received biological therapy during the first 2 years of follow-up. Data were analyzed by univariate analysis and multivariate logistic regression to predict 1-year DAS28 remission and 2-year radiographic disease progression.

Results

On univariate analysis of 399 patients, OPG/TRAIL ratio at baseline was significantly lower in patients with than without remission at 1 year (p = 0.015). On multivariate logistic regression including age, gender, body mass index and DAS28, low OPG/TRAIL ratio was independently associated with remission at 1 year (odds ratio 1.68 [95 % confidence interval 1.01–2.79]). On univariate analysis, high OPG/TRAIL ratio at baseline was associated with rapid progression of erosion at 2 years (p = 0.041), and on multivariate logistic regression including age, anti-citrullinated protein antibody positivity and C-reactive protein level, OPG/TRAIL ratio independently predicted rapid progression of erosion at 2 years.

Conclusions

OPG/TRAIL ratio at baseline was an independent predictor of 1-year remission and 2-year rapid progression of erosion for patients with early rheumatoid arthritis. Thus, OPG/TRAIL ratio could be included in matrix prediction scores to predict rapid radiographic progression. Further confirmation in an independent cohort is warranted.

Cachexia and adiposity in rheumatoid arthritis. Relevance for disease management and clinical outcomes

Altered body composition is a frequent finding in rheumatoid arthritis and is associated with the two major outcomes of the disease: disability and cardiovascular mortality. It is estimated that up to two thirds of patients may be affected by loss of lean mass, the so-called rheumatoid cachexia. Hence, body weight being equal, the relative amount of lean mass is lower and that of body fat is higher in rheumatoid arthritis patients vs. healthy controls. Both disease-related factors and other factors, like drug treatments, physical activity and nutrition contribute to modify body composition in rheumatoid arthritis. The effect of pharmacological treatments, and notably of anti-TNF drugs, on body composition is controversial. Conversely, training programs to stimulate muscle growth can restore lean mass and reduce adiposity. There is good evidence that amelioration of body composition ameliorates function and reduces disability. Currently, there is no evidence that interventions that modify body composition can reduce cardiovascular morbidity and mortality in rheumatoid arthritis.

Obesity and inflammatory arthritis: impact on occurrence, disease characteristics and therapeutic response

Overweight and obesity are increasing worldwide and now reach about one-third of the world's population. Obesity also involves patients with inflammatory arthritis. Knowing the impact of obesity on rheumatic diseases (rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis) is thus an important issue. This article first reviews the epidemiological and clinical data available on obesity in inflammatory rheumatic diseases, that is, its impact on incident disease, disease characteristics and the therapeutic response. The second part of this review gives an overview of the factors potentially involved in the specifics of inflammatory arthritis in patients with obesity, such as limitations in the clinical assessment, diet, microbiota and adipokines.

Adiponectin exacerbates collagen-induced arthritis via enhancing Th17 response and prompting RANKL expression

We previously reported adiponectin (AD) is highly expressed in the inflamed synovial joint tissue and correlates closely with progressive bone erosion in Rheumatoid arthritis (RA) patients. Here, we investigate the role of adiponectin in regulating Th17 response and the expression of receptor activator of nuclear factor-κB ligand (RANKL) in mice with CIA mice by intraarticularly injection of adiponectin into knee joints on day 17, day 20 and day 23 post first collagen immunization. The increased adiponectin expression was found in inflamed joint tissue of collagen-induced arthritis (CIA) mice. Adiponectin injection resulted in an earlier onset of arthritis, an aggravated arthritic progression, more severe synovial hyperplasia, bone erosion and osteoporosis in CIA mice. CD4(+)IL-17(+) Th17 cells, IL-17 mRNA and RANKL mRNA expression were markedly increased in the joint tissue of adiponectin treated CIA mice. Moreover, adiponectin treatment markedly enhanced Th17 cell generation from naive CD4(+) T cells in vitro, which accompanied by the high expression of Th17 transcription factor ROR-γt, and Th17 cytokine genes included IL-22 and IL-23. This study reveals a novel effect of adiponectin in exacerbating CIA progression by enhancing Th17 cell response and RANKL expression.

The role of leptin in the pathophysiology of rheumatoid arthritis

The past 20 years of research on leptin has provided important insights into its role in rheumatoid arthritis (RA). Leptin is one of the different adipokines produced by the adipose tissue that influences the endocrine system, energy homeostasis and the immune response in several ways. Leptin is known to have predominantly pro-inflammatory effects, especially in the setting of chronic inflammation. Animal models of arthritis have illustrated well the participation of leptin in the inflammatory response within the joints. In patients with RA, numerous studies have evaluated the concentrations of leptin in the bloodstream and/or the joint cavity, showing higher levels compared to control populations. Leptin has also been found to correlate with clinical or biological measurements of disease activity of RA. Conversely, the relationship between serum leptin and joint structural damage is less evident. Leptin may also promote the development of atherosclerosis in RA and may contribute to the cardiovascular consequences of the metabolic syndrome that coexists with RA. Indeed, leptin could be a link between inflammation, metabolic risk factors and cardiovascular diseases in RA. Finally, due to abnormal body composition phenotypes with an increased prevalence of obesity in RA, the therapeutic response to traditional DMARDs and/or biological agents may be attenuated. This review discusses the multiple interplays that have been described between leptin and the clinical, radiographic and therapeutic aspects of RA.

Kidney function, endothelial activation and atherosclerosis in black and white Africans with rheumatoid arthritis

Objective

To determine whether kidney function independently relates to endothelial activation and ultrasound determined carotid atherosclerosis in black and white Africans with rheumatoid arthritis (RA).

Methods

We calculated the Jelliffe, 5 Cockcroft-Gault equations, Salazar-Corcoran, Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimated glomerular filtration rate (EGFR) equations in 233 (112 black) RA patients.

Results

The CKD-EPI eGFR was <90 ml/min/1.73m² in 49.1% and 30.6% of black and white patients, respectively (odds ratio (95% confidence interval) = 2.19 (1.28–3.75), p = 0.004). EGFRs were overall consistently associated with monocyte chemoattractant protein-1 and angiopoietin 2 concentrations in white patients, and with carotid intima-media thickness and plaque in black participants. Amongst black patients, plaque prevalence was 36.7% and the area under the curve (AUC) of the receiver operating characteristic (ROC) curve was not associated with plaque presence for the MDRD equation (p = 0.3), whereas the respective relationship was significant or borderline significant (p = 0.003 to 0.08) and of similar extent (p>0.1 for comparisons of AUC (SE)) for the other 8 equations. Based on optimal eGFR cutoff values with sensitivities and specificities ranging from 42 to 60% and 70 to 91% respectively, as determined in ROC curve analysis, a low eGFR increased the odds ratio for plaque 2.2 to 4.0 fold.

Conclusion

Reduced kidney function is independently associated with atherosclerosis and endothelial activation in black and white Africans with RA, respectively. CKD is highly prevalent in black Africans with RA. Apart from the MDRD, eGFR equations are useful in predicting carotid plaque presence, a coronary heart disease equivalent, amongst black African RA patients.