Leptin in immuno-rheumatological diseases

Increased serum adipokines are associated with sarcopenia in non-obese women with rheumatoid arthritis

Large cohort studies have disclosed the association between obesity and rheumatoid arthritis (RA) risk. The sarcopenia prevalence in RA patients can be up to 31%. However, there is little information linking adipokines to sarcopenia in RA, so this study aimed to investigate whether adipokines were indeed involved in secondary sarcopenia in RA with a focus on non-obese females. Sixty-four female patients and 36 controls were included in this study. The serum adipokine levels (leptin and adiponectin) were determined by ELISA kits. The impacts of adipokines on muscle atrophy and potential autophagy were examined in mouse myoblasts, C2C12, upon treatment with recombinant leptin and adiponectin agonist (AdipoRan). Interestingly, serum adiponectin was significantly increased but the ratio of leptin/adiponectin was dramatically decreased in the RA patients with sarcopenia. After normalization by body mass, serum leptin was positively associated but adiponectin was negatively associated with muscle mass respectively, even after adjustment for fat mass. Treating C2C12 cells with leptin and AdipoRan inhibited proliferation of mature myotube respectively, as did treatment with the serum from RA patients. A combination of low leptin and high AdipoRan greatly decreased myogenin, but instead increased MAFbx and MuRF-1 as well as increased Beclin 1, Atg5, and LC3β. Taken together, our study reveals that secondary sarcopenia of RA females may be an imbalance of RA-related, but not obesity-related, increase in adipokine production; additionally, the reduced leptin/adiponectin ratio could be a better indicator in monitoring sarcopenia in non-obese RA females. Moreover, adipokine imbalance may promote muscle atrophy through inducing autophagy.

Association of adipokines with severity of knee osteoarthritis assessed clinically and on magnetic resonance imaging

Objectives

We aimed to evaluate the association between the adipokines: Leptin, Adiponectin, Resistin, and high sensitive-C-reactive protein (hs-CRP) with clinical, radiographical and magnetic resonance imaging (MRI) assessment of knee osteoarthritis (OA) severity.

Design

We performed a cross-sectional study in participants with earlier knee OA. Demographics, clinical (WOMAC), radiographical and MRI (BLOKS scoring) severity of knee OA were assessed. Serum leptin, adiponectin, resistin and hs-CRP were measured. Association of adipokines and hs-CRP with clinical, radiographic and MRI severity outcomes were evaluated using regression models with adjustment with age, sex, and body mass index (BMI).

Results

137 participants with earlier knee OA (82% women, mean ​± ​SD age: 55.5 ​± ​7.8 years) were included. Participants had moderate knee OA symptoms, mean WOMAC pain and function were 30.6 ​± ​18.0, and 31.7 ​± ​19.8 respectively. Mean BMI was 27.0 ​± ​5.9 ​kg/m2. After adjustment with age, sex and BMI, serum leptin was positively associated with osteophyte size, cartilage integrity, infrapatellar synovitis and effusion. While hs-CRP was associated with meniscus extrusion and adiponectin was associated with WOMAC pain and function.

Conclusion

Serum adipokines, particularly leptin was associated with severity of various structural defects of the knee joint on MRI beyond age, sex and BMI in earlier knee OA.

Metabolic Abnormalities, Cardiovascular Disease, and Metabolic Syndrome in Adult Rheumatoid Arthritis Patients: Current Perspectives and Clinical Implications

AIM

Rheumatoid arthritis is a prevalent worldwide disease, associated with an increased risk of multiple metabolic abnormalities that generate a higher disease burden.

OBJECTIVE

To gather the available evidence on the epidemiology, pathophysiology, current perspectives, clinical implications and prognosis of metabolic abnormalities in patients with rheumatoid arthritis.

METHODS

This is a narrative literature review. Search was conducted in PubMed, OVID, and Taylor & Francis databases, using the following MeSH terms: "Arthritis Rheumatoid", "Metabolic Diseases", and "Metabolic Syndrome".

RESULTS

This study describes the main metabolic manifestations of rheumatoid arthritis. Research has recognized that rheumatoid arthritis and metabolic abnormalities share pathophysiological mechanisms with an additive effect that increases cardiovascular risk. In that context, appropriate antirheumatic treatment can also impact on cardiovascular risk.

CONCLUSION

There are metabolic abnormalities in rheumatoid arthritis patients that increase cardiovascular risk. Therefore, it is crucial to evaluate cardiovascular risk to provide appropriate comprehensive management to reduce morbidity and mortality in patients with this disease.

Effects of Aerobic Exercise on the Serum Leptin Level and Heart Rate Variability in the Obese Girl Children

Objective

The present study examined the effects of a 16-week aerobic exercise (AE) on the serum leptin level and heart rate variability (time domain and frequency domain) in the obese girl children and correlation coefficients of changes between the serum leptin level and heart rate variability after a 16-week AE intervention.

Methods

36 participants were randomly assigned to either aerobic exercise (AE, n = 18) or obese group (n = 18). The obese girl children in the AE group conducted a 16-week (4 times per week and 60 min per time) exercise protocols, and the obese group did not perform regular physical training during 16 weeks of study. Then, the serum leptin level and HRV (time domain and frequency domain) were measured in all subjects before and after AE intervention.

Results

(1) After 16-week AE intervention, compared with pre-exercise, LF/HF decreased (P < 0.05), HF, SDNN, and RMSSD significantly increased (P < 0.05 and P < 0.01), and there was no significant difference in LF (P > 0.05) in the AE group. Nevertheless, there was no significant change before and after the test in the serum leptin level and HRV of the obese group (P > 0.05, respectively). (2) After 16-week AE intervention, compared with the obese group, SDNN and HF significantly increased (P < 0.05, respectively), LF/HF significantly decreased (P < 0.05) in the AE group, but there was no significant difference in RMSSD and LF between the obese group and AE group. (3) The reduction variables of the serum leptin level before and after the AE intervention are positively correlated with the reduction in the LF/HF (r = 0.478, P < 0.05) and negatively correlated with the increasing in the RMSSD (r = -0.482, P < 0.05). But there is no significant association between the reduction in the serum leptin level and the change of LF, HF, and SDNN (P > 0.05, respectively).

Conclusion

16-week AE significantly reduced the serum leptin level and improved cardiac autonomic function in the obese girl children. Moreover, the reduction in the serum leptin level was associated with the increase in parasympathetic activation and improved sympathetic-vagus balance after AE intervention. More research is needed to see whether the effect of exercise on leptin levels in obese girl children can reduce the risk of cardiovascular disease in adulthood.

Pre-Transplant Serum Leptin Levels and Relapse of Acute Myeloid Leukemia after Allogeneic Transplantation

Weight loss and metabolic activity influence outcome after allogeneic stem cell transplantation (alloSCT). This study evaluates pre-conditioning Leptin, a peptide hormone involved in metabolism and immune homeostasis, as a prognostic factor for survival, relapse and non-relapse mortality (NRM) following alloSCT. Leptin serum levels prior to conditioning were determined in a cohort of patients transplanted for various hematologic malignancies (n = 524) and correlated retrospectively with clinical outcome. Findings related to patients with acute leukemia (AL) from this sample were validated in an independent cohort. Low pre-conditioning serum Leptin was an independent prognostic marker for increased risk of relapse (but not of NRM and overall mortality) following alloSCT for AL of intermediate and advanced stage (beyond first complete remission). Multivariate analysis revealed a hazard ratio (HR) for relapse of 0.75 per log2 increase (0.59–0.96, p = 0.020). This effect was similar in an independent validation cohort. Pre-conditioning serum Leptin was validated as a prognostic marker for early relapse by fitting the multivariate Cox model to the validation data. Pre-conditioning serum Leptin levels may serve as an independent prognostic marker for relapse following alloSCT in intermediate and advanced stage AL patients. Prospective studies are required to prove whether serum Leptin could be used for guiding nutritional intervention in patients with AL undergoing alloSCT.

Metabolic Analysis of Potential Key Genes Associated with Systemic Lupus Erythematosus Using Liquid Chromatography-Mass Spectrometry

The biological mechanism underlying the pathogenesis of systemic lupus erythematosus (SLE) remains unclear. In this study, we found 21 proteins upregulated and 38 proteins downregulated by SLE relative to normal protein metabolism in our samples using liquid chromatography-mass spectrometry. By PPI network analysis, we identified 9 key proteins of SLE, including AHSG, VWF, IGF1, ORM2, ORM1, SERPINA1, IGF2, IGFBP3, and LEP. In addition, we identified 4569 differentially expressed metabolites in SLE sera, including 1145 reduced metabolites and 3424 induced metabolites. Bioinformatics analysis showed that protein alterations in SLE were associated with modulation of multiple immune pathways, TP53 signaling, and AMPK signaling. In addition, we found altered metabolites associated with valine, leucine, and isoleucine biosynthesis; one carbon pool by folate; tyrosine metabolism; arginine and proline metabolism; glycine, serine, and threonine metabolism; limonene and pinene degradation; tryptophan metabolism; caffeine metabolism; vitamin B6 metabolism. We also constructed differently expressed protein-metabolite network to reveal the interaction among differently expressed proteins and metabolites in SLE. A total of 481 proteins and 327 metabolites were included in this network. Although the role of altered metabolites and proteins in the diagnosis and therapy of SLE needs to be further investigated, the present study may provide new insights into the role of metabolites in SLE.

Non-polar lipid from greenshell mussel (Perna canaliculus) inhibits osteoclast differentiation

The osteoclast-dependent bone resorption process is a crucial part of the bone regulatory system. The excessive function of osteoclasts can cause diseases of bone, joint, and other tissues such as osteoporosis and osteoarthritis. Greenshell mussel oil (GSM), a good source of long chain omega-3 polyunsaturated fatty acids (LCn-3PUFAs), was fractionated into total lipid, polar lipid, and non-polar lipid components and their anti-osteoclastogenic activity tested in RAW 264.7 cell cultures. Osteoclast differentiation process was achieved after 5 days of incubation with RANKL in 24-well culture plates. Introducing the non-polar lipid fraction into the culture caused a lack of cell differentiation, and a reduction in tartrate-resistant acid phosphatase (TRAP) activity and TRAP cell numbers in a dose-dependent manner (50% reduction at the concentration of 20 μg/mL, p < 0.001). Moreover, actin ring formation was significantly diminished by non-polar lipids at 10-20 μg/mL. The bone digestive enzymes released by osteoclasts into the pit formation were also compromised by downregulating gene expression of cathepsin K, carbonic anhydrase II (CA II), matrix metalloproteinase 9 (MMP-9), and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1). This study revealed that the non-polar lipid fraction of GSM oil contains bioactive substances which possess potent anti-osteoclastogenic activity.

Shift Work Adaptation Among Police Officers: The BCOPS Study

Few studies have examined shiftwork adaptation among police officers or potential differences in disease biomarkers among adapted and maladapted shiftworkers. This study characterized shiftwork adaptation among 430 police officers from the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) study. Police officers working fixed night shifts with symptoms characteristic of adaptation and maladaptation were identified using latent class analysis (n = 242). Two approaches were applied, one with police-specific symptoms and another using more general symptoms as shiftwork adaptation indicators. Biomarkers of inflammation, heart rate variability, and cardiometabolic risk were then compared between shiftwork adaptation groups, and with officers working day shifts, after adjusting for confounding. When analyses included police-specific symptoms, maladapted shiftworkers (n = 73) had more self-reported stress, sleep disturbances, fatigue, and less social support than adapted shiftworkers (n = 169). Using more general symptoms, maladapted officers (n = 56) reported more stress and depression, and less social support than adapted officers (n = 186). In police-specific models, adjusted (least-squares) means (± standard error) of circulating interleukin-6 (IL-6) concentrations in maladapted officers (0.8 ± 0.1 ln[pg/ml]) were modestly elevated relative to adapted shiftworkers (0.7 ± 0.1 ln[pg/ml], p = .09) and relative to permanent day workers (0.5 ± 0.1 ln[pg/ml], p ≤ 0.01), and leptin levels in maladapted officers (9.6 ± 0.1 ln[pg/ml]) exceeded those in the adapted (9.4 ± 0.1 ln[pg/ml], p ≤ 0.01) and day shift groups (9.4 ± 0.1 ln[pg/ml], p = .03). In the general model, adjusted mean tumor necrosis factor-alpha (TNF-α) concentrations among maladapted officers (5.6 ± 0.23 pg/ml) exceeded the adapted (4.8 ± 0.2 pg/ml, p ≤ 0.01) and day workers (5.0 ± 0.2 pg/ml, p = .04), and insulin among maladapted officers was higher (2.4 ± 0.1 ln[uu/ml]) than the adapted group (1.8 ± 0.1 ln[uu/ml], p = .03). No differences were observed for the other biomarkers. The results suggest that maladaptation among police officers working fixed night shifts may lead to increases in leptin, insulin, IL-6, and TNF-α; however, the cross-sectional design and possible residual confounding preclude interpretation of cause and effect. Prospective studies are planned to further characterize the relationship between shiftwork maladaptation and biomarkers of chronic disease risk in this police officer cohort.

Level of Adiponectin, Leptin and Selected Matrix Metalloproteinases in Female Overweight Patients with Primary Gonarthrosis

The aim of this study was to assess levels of adiponectin (ACRP-30) and leptin in serum and synovial fluid (SF) of overweight females with primary gonarthrosis (GOA) and to look for their correlations with clinical status and the level of biochemical OA biomarkers: matrix metalloproteinase (MMP) 1, MMP-9 and tissue inhibitor of metalloproteinase (TIMP-1). The studied group consisted of 39 overweight females undergoing primary total knee arthroplasty as a result of GOA. The stage of GOA was evaluated according to Knee Society Score (KSS), Ahlbäck and Kellgren–Lawrence (K-L) scores. Peripheral blood and SF were obtained. Levels of selected biomarkers were assessed using ELISA kits. The mean level of ACRP-30 in serum valued were 8393.80 ng/mL and in SF, 774.33 ng/mL, the mean concentration of leptin in serum was 32,040.74 pg/mL and in SF, 27,332.12 pg/mL. Levels of leptin in serum and SF correlated with body mass index (BMI), (p = 0.0005, and p = 0.0002, respectively). Levels of ACRP-30 in serum was correlated with clinical scores (Ahlbäck: p = 0.0214; K-L: p = 0.0146). ACRP-30 in SF correlated with ACRP-30 in serum (p = 0.0003), tended to negatively correlate with MMP-1 in serum (p = 0.0598) and positively correlate with pro-MMP-1 in SF (p = 0.0600). To conclude, this study confirms the correlations between concentrations of both, leptin and ACRP-30, comparing serum and SF. In overweight females, leptin levels increase with BMI and ACRP-30 serum level increase in more advanced GOA stages. Finally, leptin levels were correlated with TIMP-1 serum concentration, one of the biochemical markers of GOA.

Working and safety profiles of JAK/STAT signaling inhibitors. Are these small molecules also smart?

The Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway is an important intracellular route through which many different extracellular soluble molecules, by reaching membrane receptors, can signal the nucleus. The spectrum of soluble molecules that use the JAK/STAT pathway through their corresponding receptors is quite large (almost 50 different molecules), and includes some cytokines involved in the pathogenesis of many immune-mediated diseases. Such diseases, when left untreated, present an evident hyperactivation of JAK/STAT signaling. Therefore, given the pathogenetic role of JAK/STAT, drugs known as JAK inhibitors (JAKi), that target one or more JAKs, have been developed to counteract JAK/STAT signal hyperactivation. As some hematological malignancies present an intrinsic JAK/STAT hyperactivation due to a JAK mutation, some JAKi have also been successfully used in this context. Regulatory agencies for drug administration in different countries have already approved a few JAKi in the setting of either immune-mediated diseases or hematological malignancies. Aim of this review is to describe the physiology of intracellular JAK/STAT pathway signaling and the pathological conditions associated to its dysregulation. Then, the rationale for targeting JAK in rheumatic autoimmune diseases is discussed, along with clinical data from registration studies showing the efficacy of these drugs. Finally, the excellent safety profile of JAKi is discussed in the context of the apparent poor specificity of JAK/STAT pathway signal.

Sandwich ELISA-Based Electrochemical Biosensor for Leptin in Control and Diet-Induced Obesity Mouse Model

Leptin is a peptide hormone produced primarily in adipose tissues. Leptin is considered a biomarker associated with obesity and obesity-mediated diseases. Biosensor detection of leptin in the blood may play a critical role as an indicator of dynamic pathological changes. In this paper, we introduce an electrochemical biosensor that adopts o-Phenylenediamine (oPD) on screen-printed gold electrodes (SPGEs) for detecting the leptin from a mouse model of diet-induced obesity (DIO). A linear calibration curve for the leptin concentration was obtained in the ranges from 0.1 to 20 ng/mL with a lower detection limit of 0.033 ng/mL. The leptin concentration was quantified with HRP (horseradish peroxidase)-catalyzed oxidation of oPD by two voltammetry methods: cyclic voltammetry (CV) and square-wave voltammetry (SWV). The proposed sandwich enzyme-linked immunosorbent assay (ELISA)-based electrochemical biosensor for the leptin in mouse blood serum showed high stability, sensitivity, selectivity, and effectivity compared to the commercial Leptin ELISA measurement. Thus, we believe that this leptin biosensor can be a sensitive analytical tool to detect low-levels of biomarkers in clinics and point-of-care testing (POCT).

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.

Interplay between obesity and smoking with regard to RA risk

Objectives

Previous studies on rheumatoid arthritis (RA) and body mass index (BMI) have yielded diverging results. We aimed to clarify the influence of BMI on the risk of developing anticitrullinated peptide antibody (ACPA)-positive and ACPA-negative RA by taking into consideration gender, smoking habits and human leukocyte antigen (HLA-DRB1) shared epitope (SE) status.

Methods

The present report is based on a Swedish population-based, case–control study with incident cases of RA (3572 cases, 5772 matched controls). Using logistic regression models, overweight/obese subjects were compared with normal weight subjects regarding risk of developing RA, by calculating ORs with 95% CIs.

Results

We observed diverging results for women and men. Among women, the risk of both ACPA-positive and ACPA-negative RA increased with increasing BMI, whereas an inverse association was observed among men for ACPA-positive RA. The results were similar regardless if RA onset before or after the age of 55 years was considered. When the analyses were stratified by smoking habits, the influence of BMI on RA risk was mainly restricted to smokers. Among women, a significant interaction was observed between smoking and overweight/obesity with regard to both subsets of RA. No interaction was observed between HLA-DRB1 SE and overweight/obesity with regard to RA risk.

Conclusions

The interaction between smoking and obesity regarding risk for RA in women warrants efforts to reduce these risk factors in those at risk for RA. The sex differences concerning the influence of obesity on RA risk merit further studies to verify these results and understand underlying mechanisms.

Intrauterine Malnutrition Reduced Long Leptin Receptor Isoform Expression and Proinflammatory Cytokine Production in Male Rat Pulmonary Endothelial Cells Stimulated by Lipopolysaccharide

Background/Aims

We have previously shown that low birth weight (LBW) rats exposed to intrauterine malnutrition have an impaired lung inflammatory response and reduced levels of inflammatory mediators; however, circulating leptin levels were not increased. We evaluated long leptin receptor isoform (ObRb) expression in lung endothelial cells from low birth weight rats and examined its role in the production of lipid mediators and cytokines.

Methods

Lung endothelial cells were obtained from normal birth weight (NBW) rats or LBW rats subjected to intrauterine malnutrition. These cells were stimulated with leptin (10 ng/mL), LPS (lipopolysaccharide, 1 μg/mL), or leptin plus LPS. Six hours after stimulation, the production of inflammatory mediators (PGE₂, LTB₄, IL-1β, and IL-6) was evaluated using commercial ELISA kits, and Western blotting was performed to investigate p38MAPK, NF-κB, and ObRb expression.

Results

Leptin increased IL-1β levels in only cells from the NBW group, whereas LPS increased PGE₂ and LTB₄ levels in cells from both groups; leptin addition potentiated lipid mediator production induced by LPS in the NBW group. LPS enhanced the production of IL-1β and IL-6 in only endothelial cells from NBW rats. Leptin receptor expression was decreased (63%) in endothelial cells from LBW rats. None of the stimuli increased NF-κB or p38 signaling pathway expression in cells from LBW rats.

Conclusion

These results suggest that intrauterine malnutrition compromises leptin receptor expression and cytokine production in pulmonary endothelial cells stimulated by LPS; these effects seem to involve the NF-κB and p38MAPK signaling pathways.

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.

Physical activity and sedentary behavior in patients with Systemic Lupus Erythematosus

Introduction

The aim of this study was to evaluate the proportion of patients with Systemic Lupus Erythematosus (SLE) who did not met the WHO recommendations for physical activity and to evaluate the amount of time spent in sedentary behavior.

Methods

SLE patients were consecutively enrolled in a cross sectional study. The type and the time spent in physical activity and sedentary behavior were evaluated using the IPAQ short form questionnaire. The adequate physical activity was defined according to the 2010 WHO recommendations for health and the sedentary behavior according to the 2017 SBRN consensus. We also assessed quality of life using SF-36, mood disorders using BDI and HAM-H, fatigue using Facit-Fatigue and sleep disorders using PSQI scores.

Results

Physical activity was not sufficient to meet WHO recommendations in 56 of 93 SLE patients (60%). SLE patients spent a median (95% range) of 180 (0–600) minutes everyday in sedentary activities. The length of daily sedentary time was more than 6 hours in 25% of SLE patients. In multivariable analysis, the factors associated to the probability of not meeting WHO criteria was only the time of exposure to antimalarials (OR 0.88, p 0.03) and the factors related to the probability of being in the upper tertile of sedentary time (more than 270 minutes) were age (OR 1.04, p 0.02), disease activity expressed by SELENA-SLEDAI score (OR 1.2, p 0.01) and Facit-fatigue score (OR 0.94, p 0.04).

Conclusion

A relevant proportion of SLE patients were inadequately physically active. It is essential to improve the awareness of the importance of increase physical activity and reduce sedentary time. A better control of disease activity and fatigue and a prolonged use of antimalarials could help to reach this notable goal.

The relation between, metabolic syndrome and quality of life in patients with Systemic Lupus Erythematosus

Introduction

Systemic Lupus Erythematosus (SLE) is associated to an increased prevalence of Metabolic Syndrome (MeS) and to a reduction of Quality of Life (QoL). The aim of this study is to evaluate the association between MeS and QoL in SLE.

Methods

SLE patients were consecutively enrolled in a cross sectional study. MeS was defined according to IFD definition. Therapy with glucocorticoids (GC) and antimalarial was analyzed as cumulative years of exposure. We used a cut off of 7.5 mg of prednisone to define high daily dose of GC. QoL was quantified using SF-36. We used BDI and HAM-H to assess symptoms of mood disorders. Fatigue was evaluated using Facit-Fatigue, physical activity using IPAQ, sleep quality using PSQI and alexithymia using TAS-20.

Results

We enrolled 100 SLE patients. MeS prevalence was 34%. Patients with MeS presented reduced scores in SF-36 MCS and PCS compared to patients without MeS (p 0.03 and p 0.004). BDI and HAM-H score were significantly higher in patients meeting MeS criteria compared to subjects without MeS (p 0.004, p 0.02). These results were confirmed after adjustment for confounders. Compared to patients without MeS, those with MeS presented higher age, lower education level, higher recent SELENA-SLEDAI, higher number of flares, increased SDI, longer cumulative exposure to high dose GC and shorter duration of antimalarial therapy. In the multiple logistic regression model, the variable associated to the Odds Ratio of having MeS were: the average of recent SELENA-SLEDAI (OR 1.15 p 0.04), the years of exposure to high dose of GC (OR 1.18 p 0.004), the years of exposure to antimalarials (OR 0.82 p 0.03) and the BDI score (OR 1.1 p 0.005).

Conclusion

A modern management of SLE should not miss to take all the possible measures to ensure an adequate QoL to SLE patients, with particular attention to those affected by MeS.

CD4+ T cells memorize obesity and promote weight regain

Body weight regain often causes failure of obesity therapies while the underlying mechanism remains largely unknown. In this study, we report that immune cells, especially CD4+ T cells, mediate the ‘memory’ of previous obese status. In a weight gain-loss-regain model, we found that C57BL/6J mice with an obesity history showed a much faster rate of body weight regain. This obesity memory could last for at least 2 months after previously obese mice were kept at the same body weight as non-obese mice. Surprisingly, such obesity memory was abrogated by dexamethasone treatment, whereas immunodeficient Rag1^−/− and H2A^−/− mice failed to establish such memory. Rag1^−/− mice repossessed the obesity memory when immune cells or CD4+ T cells isolated from previously obese mice were transferred. Furthermore, depletion of CD4+ T cells led to obesity memory ablation. Taken together, we conclude that CD4+ T cells mediate obesity memory and promote weight regain.

Serum levels of leptin and high molecular weight adiponectin are inversely associated with radiographic spinal progression in patients with ankylosing spondylitis: results from the ENRADAS trial

Background

Previous research indicates a role of adipokines in inflammation and osteogenesis. Hence adipokines might also have a pathophysiological role in inflammation and new bone formation in patients with ankylosing spondylitis (AS). The aim of this study was to investigate the role of adipokine serum levels as predictors of radiographic spinal progression in patients with AS.

Methods

A total of 120 patients with definite AS who completed a 2-year follow up in the ENRADAS trial were included in the current study. Radiographic spinal progression was defined as: (1) worsening of the modified Stoke Ankylosing Spondylitis spine (mSASSS) score by ≥2 points and/or (2) new syndesmophyte formation or progression of existing syndesmophytes after 2 years. Serum levels of adipokines (adiponectin (APN) and its high molecular weight form (HMW-APN), chemerin, leptin, lipocalin-2, omentin, resistin, visfatin) were measured using enzyme-linked immunosorbent assays.

Results

There was a significant association between radiographic spinal progression and both leptin and HMW-APN. Baseline serum levels of both adipokines were lower in patients who showed radiographic spinal progression after 2 years. This association was especially evident in men; they had generally lower leptin and HMW-APN serum levels as compared to women. The inverse association between adipokines and radiographic spinal progression was confirmed in the logistic regression analysis: the odds ratios (OR) for the outcome “no mSASSS progression ≥2 points” were 1.16 (95% CI 1.03 to 1.29) and 1.17 (95% CI 0.99 to 1.38), for leptin and HMW-APN, respectively; for “no syndesmophyte formation/progression” the respective OR were 1.29 (95% CI 1.11 to 1.50) and 1.18 (95% CI 0.98 to 1.42), adjusted for the presence of syndesmophytes at baseline, C-reactive protein at baseline, sex, body mass index (BMI), non-steroidal anti-inflammatory drugs intake score over 2 years, and smoking status at baseline.

Conclusion

Serum leptin and HMW-APN predict protection from spinal radiographic progression in patients with AS. Women generally have higher leptin and HMW-APN serum levels that might explain why they have less structural damage in the spine as compared to male patients with AS.

Trial registration

EudraCT: 2007-007637-39. ClinicalTrials.gov, NCT00715091. Registered on 14 July 2008.

Adipokine Contribution to the Pathogenesis of Osteoarthritis

Recent studies have shown that overweight and obesity play an important role in the development of osteoarthritis (OA). However, joint overload is not the only risk factor in this disease. For instance, the presence of OA in non-weight-bearing joints such as the hand suggests that metabolic factors may also contribute to its pathogenesis. Recently, white adipose tissue (WAT) has been recognized not only as an energy reservoir but also as an important secretory organ of adipokines. In this regard, adipokines have been closely associated with obesity and also play an important role in bone and cartilage homeostasis. Furthermore, drugs such as rosuvastatin or rosiglitazone have demonstrated chondroprotective and anti-inflammatory effects in cartilage explants from patients with OA. Thus, it seems that adipokines are important factors linking obesity, adiposity, and inflammation in OA. In this review, we are focused on establishing the physiological mechanisms of adipokines on cartilage homeostasis and evaluating their role in the pathophysiology of OA based on evidence derived from experimental research as well as from clinical-epidemiological studies.

Intrinsic Properties of Brown and White Adipocytes Have Differential Effects on Macrophage Inflammatory Responses

Obesity is marked by chronic, low-grade inflammation. Here, we examined whether intrinsic differences between white and brown adipocytes influence the inflammatory status of macrophages. White and brown adipocytes were characterized by transcriptional regulation of UCP-1, PGC1α, PGC1β, and CIDEA and their level of IL-6 secretion. The inflammatory profile of PMA-differentiated U937 and THP-1 macrophages, in resting state and after stimulation with LPS/IFN-gamma and IL-4, was assessed by measuring IL-6 secretion and transcriptional regulation of a panel of inflammatory genes after mono- or indirect coculture with white and brown adipocytes. White adipocyte monocultures show increased IL-6 secretion compared to brown adipocytes. White adipocytes cocultured with U937 and THP-1 macrophages induced a greater increase in IL-6 secretion compared to brown adipocytes cocultured with both macrophages. White adipocytes cocultured with macrophages increased inflammatory gene expression in both types. In contrast, macrophages cocultured with brown adipocytes induced downregulation or no alterations in inflammatory gene expression. The effects of adipocytes on macrophages appear to be independent of stimulation state. Brown adipocytes exhibit an intrinsic ability to dampen inflammatory profile of macrophages, while white adipocytes enhance it. These data suggest that brown adipocytes may be less prone to adipose tissue inflammation that is associated with obesity.

Why are kids with lupus at an increased risk of cardiovascular disease?

Juvenile-onset systemic lupus erythematosus (SLE) is an aggressive multisystem autoimmune disease. Despite improvements in outcomes for adult patients, children with SLE continue to have a lower life expectancy than adults with SLE, with more aggressive disease, a higher incidence of lupus nephritis and there is an emerging awareness of their increased risk of cardiovascular disease (CVD). In this review, we discuss the evidence for an increased risk of CVD in SLE, its pathogenesis, and the clinical approach to its management.

Association of Leptin with Body Pain in Women

Leptin, an appetite-regulatory hormone, is also known to act as a proinflammatory adipokine. One of the effects of increased systemic leptin concentrations may be greater sensitivity to pain. We report the results of two studies examining the association between leptin and pain: a small pilot longitudinal study, followed by a large cross-sectional study. In Study 1, three women with physician-diagnosed fibromyalgia provided blood draws daily for 25 consecutive days, as well as daily self-reported musculoskeletal pain. Daily fluctuations in serum leptin were positively associated with pain across all three participants (F (1,63) = 12.8, p < 0.001), with leptin predicting ∼49% of the pain variance. In Study 2, the relationship between leptin and body pain was examined in a retrospective cross-sectional analysis of 5676 generally healthy postmenopausal women from the Women's Health Initiative. Leptin levels obtained from single blood draws were tested for a relationship with self-reported body pain. Body mass index (BMI) was also included as a predictor of pain. Both leptin and BMI were found to be independently associated with self-reported pain (p = 0.001 and p < 0.001, respectively), with higher leptin levels and greater BMI each being associated with greater pain. Leptin appears to be a predictor of body pain both within- and between-individuals and may be a driver of generalized pain states such as fibromyalgia.

Upregulated Leptin in Periodontitis Promotes Inflammatory Cytokine Expression in Periodontal Ligament Cells

BACKGROUND

Imbalance or disruption in the expression of inflammatory mediators contributes greatly to the breakdown of the periodontal supporting tissues. Leptin, through binding to its receptor (obesity-related leptin and leptin receptor [OBR]), has potent effects on immunity and inflammation. However, to date, researchers only indicated a role of leptin in periodontitis. No direct or valid evidence exists about how leptin and its receptor are regulated by local inflammation, what effects they have, and the underlying mechanisms.

METHODS

Experimental periodontitis was induced by ligation of mandibular second molars in beagle dogs. The expression of leptin, OBR, and interleukin (IL)-1β was examined by immunohistochemistry. Meanwhile, recombinant human IL-1β was used to stimulate human periodontal ligament cells (hPDLCs) in vitro, and mRNA and protein levels of leptin were measured using real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Then, mRNA and protein levels of IL-6 and IL-8 were measured using real-time PCR and ELISA, after stimulation with various concentrations of leptin, knocking down all or only the long form of OBR (OBRb) by small interfering RNA and incubation with multiple intracellular signaling pathway inhibitors, respectively.

RESULTS

Leptin and OBR increased substantially in inflammatory periodontal tissues, which correlated well with the extent of inflammatory infiltration, and was a result of the upregulation in resident cells themselves. A high dose of leptin could induce the expression of mRNA and protein of IL-6 and IL-8 in hPDLCs through binding with OBRb and activating different intracellular signaling pathways.

CONCLUSION

Upregulated leptin and OBR in periodontitis stimulated proinflammatory cytokine expression in PDL cells to additionally promote local inflammation.

The effect of leptin on the respiratory burst of human neutrophils cultured in synovial fluid

Objectives

Leptin is a hormone responsible for nutritional status and immune competence coordination. In rheumatoid arthritis (RA) increased leptin levels were observed in both serum and synovial fluid. Its influence on development of the disease still remains unclear. So far, research on leptin's influence on the emission of reactive oxygen intermediates (ROI) measured with chemiluminescence (CL) has provided unclear and contradictory results. In this study, we evaluated the influence of leptin on oxidative activity of neutrophils isolated from blood of healthy volunteers and cultured in different amounts of synovial fluid (SF) from patients with RA.

Material and methods

Neutrophils’ oxidative metabolism was measured by two types of CL. The first one, luminol-dependent CL (CL-lum), allows one to determine phagocytic activity and the level of ROI generated in a myeloperoxidase-dependent manner. The second method used was lucigenin-dependent CL (CL-luc), which monitors ROI production dependent on the NADPH oxidase enzyme complex located in the cell membranes of neutrophils and enables one to determine the scope of extracellular ROI emission.

Results

Neutrophils stimulated by opsonized zymosan show a decrease in the level of CL-lum, proportional to the increasing concentration of both SF and serum collected from healthy donors. The observed effect of decreased CL-lum may, therefore, be dependent on the physical conditions (viscosity of fluids used). None of these experiments showed any effect of leptin on the level of CL-lum.

Conclusions

The present study showed that leptin does not affect the level of any of the CL types in inactive neutrophils incubated in normal serum, and it does not affect the level of oxidative activity in resting neutrophils incubated with SF. However, leptin influences extracellular ROI emission (measured by CL-luc). Leptin reduces extracellular emission of ROI, and this effect is dependent on concentration and duration of exposure to leptin.

Leptin, adiponectin, and heart rate variability among police officers

OBJECTIVES

Police officers have a high prevalence of cardiovascular disease (CVD). Reduced heart rate variability (HRV) is known to increase CVD risk. Leptin and adiponectin may be related to CVD health. Therefore, our objective was to investigate the relationship between these variables and HRV.

METHODS

Leptin and adiponectin levels were measured in 388 officers from the Buffalo Cardio-Metabolic Occupational Police Stress study. HRV was assessed according to methods published by the Task Force of the European Society of Cardiology and the North American Society of Pacing Electrophysiology for measurement and analysis of HRV. Mean values of high-frequency (HF) and low-frequency (LF) HRV were compared across tertiles of leptin and adiponectin using analysis of variance and analysis of covariance; trends were assessed using linear regression models.

RESULTS

Leptin, but not adiponectin, was significantly and inversely associated with HRV. Body mass index (BMI) and percent body fat significantly modified the association between leptin and LF (but not HF) HRV. Among officers with BMI < 25 kg/m(2) , leptin was not significantly associated with HRV. However, among officers with BMI ≥ 25 kg/m(2) , leptin was inversely associated with HRV, after adjustment for age, gender, and race/ethnicity; HF HRV, P = 0.019 and LF HRV, P < 0.0001. Similarly, among officers with percent body fat ≥ 25.5%, leptin and LF HRV showed significant, inverse associations (adjusted P = 0.001).

CONCLUSIONS

Leptin levels were inversely associated with LF HRV, especially among officers with increased adiposity. Increased leptin levels may be associated with CVD-related health problems.

Emerging role of leptin in rheumatoid arthritis

Numerous studies have suggested the importance of leptin against autoimmune diseases such as systemic lupus erythematosus (SLE), multiple sclerosis (MS) and psoriasis. To summarize our current understanding of the role of leptin in inflammatory responses and rheumatoid arthritis (RA), a systematic review was conducted to assess the discrepancy of leptin in RA and its effect on immunity according to different studies. Recently, emerging data have indicated that leptin is involved in the pathological function of RA, which is common in autoimmune disorders. This review discusses the possible consequences of leptin levels in RA. Blocking the key signal pathways of leptin and inhibiting the leptin activity-like leptin antagonist may be a promising way for potential therapeutic treatment of RA at risk of detrimental effects. However, leptin was increased in patients with RA and may also regulate joint damage. Thus, more understanding of the mechanism of leptin in RA would be advantageous in the future.

Serum leptin levels in pemphigus: a case control study

BACKGROUND

Pemphigus is an autoimmune blistering disease mediated by autoantibodies directed against keratinocyte adhesion molecules. Leptin, an adipocyte-derived hormone, plays a role in immune responses and promotes autoimmunity.

OBJECTIVES

This study was conducted to determine whether serum leptin levels are altered in pemphigus patients and whether there is any correlation between leptin levels and the severity of disease.

METHODS

This study included 47 newly diagnosed patients with pemphigus and 43 age- and sex-matched healthy controls. Clinical characteristics and pemphigus area and activity score (PAAS) were assessed. Serum leptin levels (ng/mL) were measured by a commercial enzyme-linked immunosorbent assay (ELISA).

RESULTS

Patients did not differ significantly in serum leptin levels from healthy controls (median (range): 10.8 (0.1-110) ng/mL versus 12 (0.5-69.9) ng/mL and P = 0.53). There was no significant association between serum leptin concentrations and severity of disease measured by PAAS (r s = 0.06, P = 0.70).

CONCLUSION

The results suggest that pemphigus does not have a direct influence on serum leptin levels and the pathogenesis of pemphigus seems to be not dependent on the connection with adipose tissue.

Metreleptin for metabolic disorders associated with generalized or partial lipodystrophy

Lipodystrophy is a group of acquired and inherited disorders characterized by selective loss of adipose tissue. Despite wide genotypic and phenotypic variety, many patients with lipodystrophy have similar metabolic complications including insulin resistance, diabetes mellitus, hypertriglyceridemia and hepatic steatosis. Often, these metabolic abnormalities are severe and difficult to treat with conventional glucose and lipid-lowering therapies. Lack of adipose tissue also results in marked hypoleptinemia, and there has recently been much interest in using leptin-replacement therapy to treat the metabolic complications of lipodystrophy. Administration of metreleptin, the human recombinant leptin analogue, has been shown in prospective, open-label studies to improve glucose control, dyslipidemia and steatohepatitis. This article summarizes the current evidence for the safety and efficacy of leptin-replacement therapy in patients with lipodystrophy.

Leptin's role in lipodystrophic and nonlipodystrophic insulin-resistant and diabetic individuals

Leptin is an adipocyte-secreted hormone that has been proposed to regulate energy homeostasis as well as metabolic, reproductive, neuroendocrine, and immune functions. In the context of open-label uncontrolled studies, leptin administration has demonstrated insulin-sensitizing effects in patients with congenital lipodystrophy associated with relative leptin deficiency. Leptin administration has also been shown to decrease central fat mass and improve insulin sensitivity and fasting insulin and glucose levels in HIV-infected patients with highly active antiretroviral therapy (HAART)-induced lipodystrophy, insulin resistance, and leptin deficiency. On the contrary, the effects of leptin treatment in leptin-replete or hyperleptinemic obese individuals with glucose intolerance and diabetes mellitus have been minimal or null, presumably due to leptin tolerance or resistance that impairs leptin action. Similarly, experimental evidence suggests a null or a possibly adverse role of leptin treatment in nonlipodystrophic patients with nonalcoholic fatty liver disease. In this review, we present a description of leptin biology and signaling; we summarize leptin's contribution to glucose metabolism in animals and humans in vitro, ex vivo, and in vivo; and we provide insights into the emerging clinical applications and therapeutic uses of leptin in humans with lipodystrophy and/or diabetes.

Role of leptin in autoimmune diseases

Leptin represents a link between metabolism, nutritional status, and immune responses. Leptin is important for optimal functioning of the immune system. Leptin is a cytokine-like hormone with proinflammatory properties linked to autoimmune diseases. Moreover, there has been increasing evidence that leptin is involved in the pathogenesis of various autoimmune diseases. Leptin has been shown to enhance immune reactions in autoimmune diseases that are commonly associated with inflammatory responses. Both high and low levels of leptin might contribute to autoimmune diseases. Leptin has been explored as a potential target for therapeutic development in treating autoimmune diseases. In this review, we review here the most recent advances on the role of leptin in autoimmunity and in immune-rheumatological diseases.

Leptin revisited: its mechanism of action and potential for treating diabetes

Since the discovery of leptin in 1994, we now have a better understanding of the cellular and molecular mechanisms underlying its biological effects. In addition to its established anti-obesity effects, leptin exerts antidiabetic actions that are independent of its regulation of body weight and food intake. In particular, leptin can correct diabetes in animal models of type 1 and type 2 diabetes. In addition, long-term leptin replacement therapy improves glycaemic control, insulin sensitivity and plasma triglycerides in patients with severe insulin resistance due to lipodystrophy. These results have spurred enthusiasm for the use of leptin therapy to treat diabetes. Here, we review the current understanding of the glucoregulatory functions of leptin, emphasizing its central mechanisms of action and lessons learned from clinical studies, and discuss possible therapeutic applications of leptin in the treatment of type 1 and type 2 diabetes.

Sleep duration and biomarkers of metabolic function among police officers

OBJECTIVE

To investigate associations between sleep duration and biomarkers of metabolic function among police officers.

METHODS

Metabolic markers were measured using standardized methods and sleep duration was assessed from questionnaire data. Mean levels of leptin and adiponectin were assessed across five levels of sleep duration using ANCOVA and linear regression models.

RESULTS

Police officers (n = 443) who reported an average of less than 5 hours and at least 8 hours of sleep had higher levels of leptin compared to those who reported an average of 5 to 7 hours of sleep. These associations were stronger and statistically significant among women, officers with BMI of 24.9 kg/m or less and smaller abdominal height (< 20 cm), and officers who primarily worked on the day shift.

CONCLUSION

Short and long sleep duration were associated with higher leptin levels and may have implications for obesity-related conditions.