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

The role of anti-citrullinated protein antibody in pathogenesis of RA

Rheumatoid arthritis (RA) is a common autoimmune rheumatic disease that causes chronic synovitis, bone erosion, and joint destruction. The autoantigens in RA include a wide array of posttranslational modified proteins, such as citrullinated proteins catalyzed by peptidyl arginine deiminase4a. Pathogenic anti-citrullinated protein antibodies (ACPAs) directed against a variety of citrullinated epitopes are abundant both in plasma and synovial fluid of RA patients. ACPAs play an important role in the onset and progression of RA. Intensive and extensive studies are being conducted to unveil the mechanisms of RA pathogenesis and evaluate the efficacy of some investigative drugs. In this review, we focus on the formation and pathogenic function of ACPAs.

Circulating leptin and its correlation with rheumatoid arthritis activity: a meta-analysis

Objective

The aim of the study was to investigate the association between the levels of leptin in the circulating of individuals with rheumatoid arthritis (RA) and the severity of the disease.

Methods

We looked through the databases of Embase, Medline, and the Cochrane Library. We conducted a meta-analysis on the correlations between circulating leptin and the Disease Activity Score 28-erythrocyte sedimentation rate (DAS28-ESR) and C-reactive protein (CRP) levels in RA patients, as well as a meta-analysis of circulating or circulating leptin levels in RA patients.

Results

This meta-analysis study analyzed 42 different comparisons from 37 different publications, including a total of 2,350 patients with RA and 1,815 controls. The RA group had substantially higher leptin levels than the control group (standardized mean difference [SMD]=0.507, 95% confidence interval [CI]=0.309~0.704, p<0.001). The finding that RA patients had higher leptin levels was unaffected by sample size. The correlation between circulating leptin levels and DAS28 is statistically significant (correlation coefficient=0.247, 95% CI=0.087~0.396, p=0.003). Leptin levels are also correlated with CRP levels (correlation coefficient=0.203, 95% CI=0.048~0.349, p=0.010).

Conclusion

This comprehensive meta-analysis demonstrates that the circulating leptin levels of RA patients are elevated, and provides compelling evidence of the significant relationship between leptin levels and the activity of RA. The findings of this research suggest that leptin plays a significant role in the pathophysiology of this disease.

The Hypertriglyceridemic Waist Phenotype Is Associated with Several Cardiovascular Risk Factors in Women with Rheumatoid Arthritis

Rheumatoid arthritis (RA) associates with cardiovascular risk factors (CVRF) such as dyslipidemias and systemic inflammation. Cardiovascular Disease (CVD) is the leading cause of mortality. The hypertriglyceridemic waist phenotype (HTWP) identifies increased CVRF; however, information about HTWP on RA is scarce.

OBJECTIVE

To evaluate the association of HTWP with CVRF in RA.

MATERIAL AND METHODS

Cross-sectional study. Women (125) with RA were included (ACR, 1987). Anthropometry, bioimpedance, body mass index (BMI), disease activity score 28 (DAS28), and health assessment questionnaire disability index (HAQ-Di) were determined. The lipid profile determination includes the atherogenic index (AI) (TC/HDL) and Framingham Risk Score. HTWP is defined as a waist circumference ≥88 cm and triglycerides ≥ 150 mg/dL. Chi-squared and Student's t-tests were applied for comparisons.

RESULTS

HTWP was found in 38 (30.4%) patients. The subgroup with HTWP had a greater frequency of arterial hypertension (AHT) (57.9 vs. 37.9, p = 0.04), Type 2 DM (23.7 vs. 8.0, p= 0.02), BMI (29.7 ± 3.2, vs. 26.8 ± 4.3, p < 0.001), fat mass (39.3 ± 4.8 vs. 34.7 ± 6.8, p < 0.001), and AI (4.7 ± 1.2 vs. 3.7 ± 1.0, p < 0.001). No differences between DAS28 and HAQ-Di were found. HTWP was associated with the presence of MetS and CVR (p < 0.001 and p = 0.012, respectively).

CONCLUSION

The HTWP in RA is associated with CVRF, and its potential predictive role should be evaluated in longitudinal studies.

Pathogenic mechanisms involving the interplay between adipose tissue and autoantibodies in Rheumatoid arthritis

We aimed to evaluate the association between adipose tissue (AT) dysfunction, autoimmunity, and disease activity in rheumatoid arthritis (RA). A cross-sectional study including 150 RA patients and 50 healthy donors and longitudinal study with 122 RA patients treated with anti-tumor necrosis factor (TNF)-α, anti-interleukin 6 receptor (IL6R) or anti-CD20 therapies for 6 months were carried out. In vitro experiments with human AT and adipocyte and macrophage cell lines were performed. A collagen-induced arthritis mouse model was developed. The insulin resistance and the altered adipocytokine profile were associated with disease activity, the presence of anti-citrullinated proteins anti-bodies (ACPAs), and worse response to therapy in RA. AT in the context of arthritis is characterized by an inflammatory state alongside the infiltration of macrophages and B/plasmatic cells, where ACPAs can have a direct impact, inducing inflammation and insulin resistance in macrophages and promoting a defective adipocyte differentiation, partially restored by biologicals.

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IR is related to disease activity, inflammation, and autoimmunity in RA patients

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IR state and adipocytokines might be associated with a worse response to biologics

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Visfatin could be used as a potential biomarker of subclinical atherosclerosis

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ACPAs might directly impact adipose tissue

Atherosclerosis in Rheumatoid Arthritis: Promoters and Opponents

Substantial epidemiological data identified cardiovascular (CV) diseases as a main cause of mortality in patients with rheumatoid arthritis (RA). In light of this, RA patients may benefit from additional CV risk screening and more intensive prevention strategies. Nevertheless, current algorithms for CV risk stratification still remain tailored on general population and are burdened by a significant underestimation of CV risk in RA patients. Acute CV events in patients with RA are largely related to an accelerated atherosclerosis. As pathophysiological features of atherosclerosis overlap those occurring in the inflamed RA synovium, the understanding of those common pathways represents an urgent need and a leading challenge for CV prevention in patients with RA. Genetic background, metabolic status, gut microbiome, and systemic inflammation have been also suggested as additional key pro-atherosclerotic factors. The aim of this narrative review is to update the current knowledge about pathophysiology of atherogenesis in RA patients and potential anti-atherosclerotic effects of disease-modifying anti-rheumatic drugs.

Adipocytokines: Are they the Theory of Everything?

INTRODUCTION

Adipose tissue secretes various bioactive peptides/proteins, immune molecules and inflammatory mediators which are known as adipokines or adipocytokines. Adipokines play important roles in the maintenance of energy homeostasis, appetite, glucose and lipid metabolism, insulin sensitivity, angiogenesis, immunity and inflammation. Enormous number of studies from all over the world proved that adipocytokines are involved in the pathogenesis of diseases affecting nearly all body systems, which raises the question whether we can always blame adipocytokines as the triggering factor of every disease that may hit the body.

OBJECTIVE

Our review targeted the role played by adipocytokines in the pathogenesis of different diseases affecting different body systems including diabetes mellitus, kidney diseases, gynecological diseases, rheumatologic disorders, cancers, Alzheimer's, depression, muscle disorders, liver diseases, cardiovascular and lung diseases.

METHODOLOGY

We cited more than 33 recent literature reviews that discussed the role played by adipocytokines in the pathogenesis of different diseases affecting different body systems.

CONCLUSION

More evidence is being discovered to date about the role played by adipocytokines in more diseases and extra research is needed to explore hidden roles played by adipokine imbalance on disease pathogenesis.

Association of Body Dysmorphic Disorder with Leptin Levels in Patients with Normal Weight Undergoing Liposuction: A Matched Case Study

Liposuction is the most common aesthetic surgical procedure performed globally. Some of the patients with normal weight who seek liposuction may suffer from body dysmorphic disorder (BDD). Leptin, which is mainly produced by adipose tissue, may be associated with this condition. The aim of this study was to determine the prevalence of BDD and leptin levels in patients with normal weight seeking liposuction.

Clinical associations of serum leptin and leptin/adiponectin ratio in systemic sclerosis

INTRODUCTION

Leptin and adiponectin have recently received the attention of researchers as attractive biomarkers in systemic sclerosis (SSc) because of their role in the inflammatory process, vascular function and fibrosis. We hypothesized that leptin and adiponectin may be associated with disease activity and severity in patients with SSc.

AIM

To compare serum leptin, adiponectin and leptin/adiponectin levels in patients with SSc and healthy controls and to evaluate their possible relationship with frequently used laboratory markers and clinical findings.

MATERIAL AND METHODS

The study included 48 Caucasian female patients with SSc and 38 healthy controls. Serum concentrations of leptin and adiponectin were measured in patients and controls using commercially available ELISA Kits (Quantikine ELISA Kit R&D Systems, Minneapolis, MN, USA). The results were assessed by the Mann-Whitney U-test and Spearman's correlation test.

RESULTS

Leptin and adiponectin levels correlated with body mas index in SSc patients (r = 0.495, p = 0.000398 and r = -0.306; p = 0.0342) in contrast to healthy controls (p = 0.070 and p = 0.256, respectively), and, in SSc patients only, a strong negative correlation was observed between leptin and adiponectin serum levels (r = -0.314; p = 0.0312). Diffuse form of the disease (dcSSc) was associated with significantly lower serum adiponectin levels (8638.62 ±10382.62). Active disease was associated with significantly lower leptin concentration (13700.49 ±18293.32) and there was a significant negative correlation between leptin serum level and activity index score (r = -0.342; p = 0.0185).

CONCLUSIONS

The results of our study indicate that leptin levels might correlate with disease activity and subtype in SSc patients.

Adipocytokines in Rheumatoid Arthritis: The Hidden Link between Inflammation and Cardiometabolic Comorbidities

Rheumatoid arthritis is a chronic autoimmune disease affecting typically synovial joints and leading to progressive articular damage, disability, and reduced quality of life. Despite better recent therapeutic strategies improving long-term outcomes, RA is associated with a high rate of comorbidities, infections, malignancies, and cardiovascular disease (CVD). Remarkably, some well-known pathogenic proinflammatory mediators in RA, such as interleukin-1β (IL-1β) and tumor necrosis factor (TNF), may play a pivotal role in the development of CVD. Interestingly, different preclinical and clinical studies have suggested that biologic agents commonly used to treat RA patients may be effective in improving CVD. In this context, the contribution of adipocytokines has been suggested. Adipocytokines are pleiotropic molecules, mainly released by white adipose tissue and immune cells. Adipocytokines modulate the function of different tissues and cells, and in addition to energy homeostasis and metabolism, amplify inflammation, immune response, and tissue damage. Adipocytokines may contribute to the proinflammatory state in RA patients and development of bone damage. Furthermore, they could be associated with the occurrence of CVD. In this study, we reviewed available evidence about adipocytokines in RA, because of their involvement in disease activity, associated CVD, and possible biomarkers of prognosis and treatment outcome and because of their potential as a possible new therapeutic target.

Influence of serum leptin levels and Q223R leptin receptor polymorphism on clinical characteristic of patients with rheumatoid arthritis from Western Mexico

OBJECTIVE

The aim of the present study was to evaluate the possible association between the Q223R Leptin receptor (LEPR) polymorphism (A>G; rs1137101) and leptin levels in patients with rheumatoid arthritis (RA) from Western Mexico.

METHODS

A cross-sectional study was performed with 70 RA patients and 74 controls subject (CS). Disease activity was evaluated using DAS28 score, the Q223R LEPR polymorphism was determined by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and serum leptin levels, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and rheumatoid factor (RF) were quantified.

RESULTS

RA patients had significant high serum leptin levels compared with CS; leptin levels correlated strongly with body composition measures, but not with inflammatory markers, disease evolution, and activity. The genotype and allele frequencies of the Q223R LEPR polymorphism were not associated with RA. Similarly, leptin levels did not differ between Q223R LEPR genotypes.

CONCLUSION

The LEPR Q223R polymorphism was not associated with RA risk in patients from Mexican population, even though high levels of serum leptin were present and these could explain the low weight observed in RA patients when they were compared to control subjects. However, the serum leptin levels did not correlate with inflammatory markers, severity and disease evolution.

Leptin in autoimmune mechanisms of systemic rheumatic diseases

In the last two decades, white adipose tissue (WAT) has been recognized as a key actor of many physiological and pathological conditions. WAT is able to produce mediators, named "adipokines", which may affect systemic homeostasis. In particular, leptin is not only involved in appetite and energy metabolism, but also in immune system. Increasing evidence established that leptin can regulate both innate and adaptive immunity mainly with pro-inflammatory effects but also, to a lesser extent, with anti-inflammatory features. In autoimmune diseases, a failure or breakdown of the mechanisms of self-tolerance is observed. Leptin, which plays an important role in the control of immune balance, has been involved in autoimmunity generation and maintenance. In this review, it has been provided an up-to-date report about the role of leptin in systemic autoimmune diseases, with particular reference to connective tissue diseases, inflammatory arthritis, and vasculitis.

Association of leptin and leptin receptor gene polymorphisms with systemic lupus erythematosus in a Chinese population

To explore the association of LEP and leptin receptor (LEPR) gene single‐nucleotide polymorphisms (SNPs) with susceptibility to systemic lupus erythematosus (SLE) in a Chinese population. Four LEPSNPs (rs11761556, rs12706832, rs2071045 and rs2167270) and nine LEPRSNPs (rs10749754, rs1137100, rs1137101, rs13306519, rs8179183, rs1805096, rs3790434, rs3806318 and rs7518632) were genotyped in a cohort of 633 patients with SLE and 559 healthy controls. Genotyping of SNPs was performed with improved multiple ligase detection reaction (iMLDR). No significant differences were detected for the distribution of allele and genotype frequencies of all 13 SNPs between patients with SLE and controls. The genotype effects of recessive, dominant and additive models were also analysed, but no significant evidence for association was detected. However, further analysis in patients with SLE showed that the TT genotype and T allele frequencies of the LEP rs2071045 polymorphism were nominally significantly higher in patients with pericarditis (P = 0.012, P = 0.011, respectively). In LEPR, the GA/AA genotype and A allele frequencies of the rs1137100 polymorphism were both nominally associated with photosensitivity in patients with SLE (P = 0.043, P = 0.018, respectively). Moreover, the genotype and allele distribution of rs3806318 were also nominally associated with photosensitivity in patients with SLE (P = 0.013, P = 0.008, respectively). No significant differences in serum leptin levels were observed in patients with SLE with different genotypes. In summary, LEP and LEPRSNPs are not associated with genetic susceptibility to SLE, but may contribute to some specific clinical phenotype of this disease; further studies are necessary to elucidate the exact role of LEP and LEPR genes in the pathogenesis of SLE.

Characteristics of resistin in rheumatoid arthritis angiogenesis

Adipokines have been reported to be involved in the regulation of various physiological processes, including the immune response. Rheumatoid arthritis (RA) is an example of a systemic immune disease that causes chronic inflammation of the synovium and bone destruction in the joint. Recent therapeutic strategies based on the understanding of the role of cytokines and cellular mechanisms in RA have improved our understanding of angiogenesis. On the other hand, endogenous endothelial progenitor cells, which are a population isolated from peripheral blood monocytes have recently been identified as a homing target for pro-angiogeneic factor and vessel formation. In this review, we summarize the effects of common adipokines, such as adiponectin, leptin and resistin in RA pathogenesis and discuss other potential mechanisms of relevance for the therapeutic treatment of RA.