Systemic blockade of TNF-α does not improve insulin resistance in humans

The effects of anti-TNF-α biologics on insulin resistance and insulin sensitivity in patients with rheumatoid arthritis: An update systematic review and meta-analysis

BACKGROUND AND AIM

Increasing evidence demonstrates a link between the chronic inflammatory state in patients with rheumatoid arthritis (RA) and the development of insulin resistance. It is thought that anti-TNF-α biologic therapy may improve insulin sensitivity and ameliorate insulin resistance by the downregulation of inflammatory cytokines, however, pre-clinical and clinical studies have yielded conflicting results. A meta-analysis on this topic is necessary to summarize current evidence and generate hypotheses for future research.

METHODS

Literature search was performed in four databases, namely PubMed, EMBASE, Scopus, and The Cochrane Library, from inception till April 9, 2023, querying studies reporting peripheral insulin resistance with and without anti-TNF-α use in patients with RA. Peripheral insulin resistance or sensitivity was quantified by the Homeostasis Model Assessment of Insulin Resistance (HOMA) index or the Quantitative Insulin Sensitivity Check Index (QUICKI) respectively. The difference in insulin resistance or sensitivity between the treatment and control group was calculated using standardized mean difference (SMD) for the purposes of the meta-analysis.

RESULTS

Twelve articles were reviewed, with 10 longitudinal studies with a total of 297 patients included in the meta-analysis. The pooled standardized mean difference (SMD) from baseline HOMA was -0.82 (95% CI: -1.38 to -0.25) suggesting significant beneficial effects of anti-TNF-α therapy on insulin resistance.

CONCLUSION

Current evidence supports the significant clinical efficacy of anti-TNF-α biologics in alleviating insulin resistance and improving insulin sensitivity in patients with active RA.

Salsalate: a pleotropic anti-inflammatory drug in the treatment of diabetes, obesity, and metabolic diseases

Type two Diabetes Mellitus (T2DM) is a rising epidemic. Available therapeutic strategies have provided glycaemic control via HbA1c reduction but fail to provide clinically meaningful reduction in microvascular and macrovascular (cardiac, renal, ophthalmological, and neurological) complications. Inflammation is strongly linked to the pathogenesis of T2DM. Underlying inflammatory mechanisms include oxidative stress, endoplasmic reticulum stress amyloid deposition in the pancreas, lipotoxicity, and glucotoxicity. Molecular signalling mechanisms in chronic inflammation linked to obesity and diabetes include JANK, NF-kB, and AMPK pathways. These activated pathways lead to a production of various inflammatory cytokines, such as Interleukin (IL-6), tumor necrosis factor (TNF)-alpha, and C-reactive protein (CRP), which create a chronic low-grade inflammation and ultimately dysregulation of glucose homeostasis in the liver, skeletal muscle, and smooth muscle. Anti-inflammatory agents are being tested as anti-diabetic agents such as the IL-1b antagonist, Anakinra, the IL-1b inhibitor, Canakinuma, the IL-6 antagonists such as Tocilizumab, Rapamycin (Everolimus), and the IKK-beta kinase inhibitor, Salsalate. Salsalate is a century old safe anti-inflammatory drug used in the treatment of arthritis. Long-term safety and efficacy of Salsalate in the treatment of T2DM have been evaluated, which showed improved fasting plasma glucose and reduced HbA1C levels as well as reduced pro-inflammatory markers in T2DM patients. Current publication summarizes the literature review of pathophysiology of role of inflammation in T2DM and clinical efficacy and safety of Salsalate in the treatment of T2DM.

Disease-modifying anti-rheumatic drugs associated with different diabetes risks in patients with rheumatoid arthritis

OBJECTIVES

Patients with rheumatoid arthritis are prone to developing diabetes, which may lead to various sequelae and even cardiovascular diseases, the most common cause of death in such patients. Previous research has shown that some rheumatoid arthritis treatments may help prevent the development of diabetes. This study aimed to investigate whether patients using disease-modifying anti-rheumatic drugs (DMARDs) may have different levels of risk for diabetes and to analyse other risk factors for diabetes.

METHODS

This cohort study used data from the Chang Gung Research Database. 5530 adults with rheumatoid arthritis but without diabetes were eligible for the analysis. The endpoint of this study was new-onset diabetes, defined as an HbA1c value ≥7% during follow-up. The entire follow-up period was divided into monthly subunits. These 1-month units were then divided into methotrexate (MTX) monotherapy, any biological DMARDs (bDMARDs), MTX combination, other conventional DMARDs (cDMARDs) and non-DMARDs.

RESULTS

A total of 546 participants (9.87%) developed diabetes between 2001 and 2018. The risk of diabetes was significantly lower in the bDMARD periods (HR 0.51; 95% CI 0.32 to 0.83), MTX combination periods (HR 0.50; 95% CI 0.32 to 0.78) and other cDMARD periods (HR 0.56; 95% CI 0.37 to 0.84) than in the MTX monotherapy periods. Individual drug analysis showed that hydroxychloroquine (HR 0.52; 95% CI 0.42 to 0.65) reduced the risk of diabetes. Tumour necrosis factor-α inhibitors (HR 0.69; 95% CI 0.46 to 1.03) tended to be protective.

CONCLUSION

Patients with rheumatoid arthritis may have different levels of risk of diabetes depending on the treatment options.

Effects of biologic and target synthetic disease-modifying anti-rheumatic drugs on sarcopenia in spondyloarthritis and rheumatoid arthritis: a systematic review and meta-analysis

Sarcopenia is a syndrome defined by generalized and progressive loss of skeletal muscle mass, strength, and function. Besides affecting elderly population, it is actually common among inflammatory rheumatic diseases (IRD) patients. We performed a systematic literature review with a meta-analysis to investigate the influence of biologic and target synthetic disease-modifying anti-rheumatic drugs (bDMARDs/tsDMARDs) on sarcopenia in IRD. A systematic search has been performed on Pubmed, Scopus, and Web of science. Studies characteristics were collected. Assessment tools were body composition (total lean mass (TLM) and percentage, appendicular skeletal mass (ASM), fat-free mass and index (FFM and FFMI), skeletal mass index (SMI) and segmental lean mass (SLM)), and muscle strength and physical performance tests. Treatment effect defined the difference in change from baseline to the end of follow-up treatment was divided by the pooled SD of the difference. Twenty-two studies on 778 patients receiving bDMARDs/tsDMARDs and 157 controls were reviewed. They investigated rheumatoid arthritis (RA) (N = 14), spondyloarthritis (SpA) (N = 6), psoriatic arthritis (N = 1), and both RA and SpA (N = 1). tsDMARDs were used in one study with no effect on sarcopenia. Ten studies demonstrated that bDMARDs increased significantly muscle measures in 347 patients (44.6%) with a significant increase in TLM (6/15 studies; 57.4%), FFMI (4/6 studies; 59.9%), ASM (2/5 studies; 17.6%), SMI (2/5 studies; 18.1%), and SLM (2/2 studies; 3.6%). bDMARDs showed also a positive effect on handgrip strength in 1/3 of studies (45.2%) and on physical performance in 1/2 of studies (61%). In 1/5 of comparative studies, IRD patients on bDMARDs showed significantly higher increase of TLM in comparison to controls naïve bDMARDs. Regarding diagnosis, positive effect of bDMARDs was seen in 67.4% in SpA versus 49.3% in RA, with a significant increase of TLM, ASM and FFMI in 59.4%, 100%, and 65.2% in SpA versus 54.9%, 24.1%, and 54.8% in RA, respectively. Meta-analysis assessed the effect of bDMARD on TLM in 10 studies. There was no statistically significant difference [SMD - 0.10 (95% Confidence Interval - 0.26 - 0.06; tau² = 0). Heterogeneity across studies was null, and the 95% confidence interval (index of precision) was equal to the 95% predictive interval. The first systematic literature review showed that bDMARDs have a significant improve effect in nearly half of RA and SpA patients on muscle mass and muscle strength, assessed separately. However, the meta-analysis concluded that bDMARDs have no significant effect on TLM.

The effect of disease-modifying anti-rheumatic drugs on skeletal muscle mass in rheumatoid arthritis patients: a systematic review with meta-analysis

INTRODUCTION

Rheumatoid arthritis (RA) is an autoimmune disease, characterized by chronic and systemic inflammation. Besides, it is known that RA patients may present several comorbidities, such as sarcopenia, a condition where patients present both muscle mass and muscle quality impairment. RA treatment is mostly pharmacological and consists in controlling systemic inflammation and disease activity. Despite that, the effect of pharmacological treatment on sarcopenia is not well characterized.

OBJECTIVE

To summarize the effects of disease-modifying anti-rheumatic drugs (DMARDs) on skeletal muscle tissue in rheumatoid arthritis (RA) patients.

METHODS

A systematic review of randomized clinical trials and observational studies was conducted using MEDLINE, Embase, Cochrane Library, and Web of Science. We selected studies with rheumatoid arthritis patients treated with disease-modifying anti-rheumatic drugs (DMARDs) that analyzed muscle mass parameters such as lean mass and appendicular lean mass. Methodological quality was assessed using the Newcastle-Ottawa Quality Assessment Scale. Standardized mean difference (SMD) and 95% confidence intervals (CI) were set. A meta-analysis of observational studies was performed using the R software, and we considered significant statistics when p < 0.05.

RESULTS

Nine studies were included in this systematic review. In the meta-analysis, DMARD treatment had no positive difference (p = 0.60) in lean mass. In the same way, in the appendicular lean mass parameter, our results showed that DMARDs did not have changes between baseline and post-treatment analysis (p = 0.93).

CONCLUSION

There is no evidence of a significant effect of DMARD therapy, either synthetic or biological, on muscle mass. However, this association should be investigated with more studies.

Effect of biological disease-modifying antirheumatic drugs on body composition in patients with rheumatoid arthritis: a systematic review and meta-analysis

Background

Rheumatoid arthritis (RA) generates an inflammatory profile that predisposes to total and visceral fatty accumulation and reduced fat free mass (FFM). This metabolic disorder contributes to poor functionality, increased cardiovascular risk and higher mortality. This study aimed to address a systematic review with meta-analysis to determine the effect of biological and targeted synthetic disease-modifying antirheumatic drugs (bDMARDs and tsDMARDs) on body composition (BC) of patients with RA.

Methods

The search was conducted at the electronic databases PubMed, Cochrane Library, Embase, Lilacs and grey literature. This investigation was carried until July 2021. Outcomes of interest were total weight, body mass index (BMI), fat mass (FM) and FFM. A meta-analysis comparing these outcomes in RA patients under bDMARD treatment versus controls was performed.

Results

Out of 137 studies reviewed, 18 were selected: fifteen prospective cohorts, two retrospective cohorts, and one cross-sectional study. The studies comprised 1221 patients, 778 on bDMARD treatment and 443 controls, which included RA patients under conventional synthetic DMARD (csDMARD). No study addressing BC analysis in patients using tsDMARD was found. The mean age and duration of the disease was 56.7 years and 6.77 years, respectively. Ten studies demonstrated a significant increase of total weight in 88.2% of patients and 42.3% for BMI. In studies that analyzed BC by double X-ray absorptiometry (DXA), the increase in total weight and BMI correlated positively to the increase in FFM. The meta-analysis carried out in five studies showed no significant difference of the mean difference for total weight 0.12 kg (95% CI − 5.58, 5.82), BMI 0.08 kg/m2 (95% CI − 1.76, 1.92), FM − 0.08 kg (95% IC − 5.31, 5.14), and FFM − 2.08 kg (95% CI − 7.37, 3.21).

Conclusion

This systematic review suggests a possible impact of bDMARDs on BC of RA patients, even though, the meta-analysis carried out in a small part of these studies was not able to confirm significant variation in BC components.

Trial registration: PROSPERO code: CRD42020206949.

Association of Gender, Diagnosis, and Obesity With Retention Rate of Secukinumab in Spondyloarthropathies: Results Form a Multicenter Real-World Study

Background: Secukinumab has been shown effective for psoriatic arthritis (PsA) and axial spondylarthritis (AxSpA) in randomized trials. The aim of this study was to analyze baseline patient and disease characteristics associated with a better retention rate of secukinumab under real-world conditions.

Patients and Methods: Real-life, prospective multicenter observational study involving 138 patients, 61 PsA and 77 AxSpA, who were analyzed at baseline, 6, 12 months and subsequently every year after starting secukinumab regardless of the line of treatment. Demographics and disease characteristics, measures of activity, secukinumab use, and adverse events were collected. Drug survival was analyzed using Kaplan-Meier curves and factors associated with discontinuation were evaluated using Cox regression. The machine-learning J48 decision tree classifier was also applied.

Results: During the 1st year of treatment, 75% of patients persisted with secukinumab, but accrued 71% (n = 32) in total losses (n = 45). The backward stepwise (Wald) method selected diagnosis, obesity, and gender as relevant variables, the latter when analyzing the interactions. At 1 year of follow-up, the Cox model showed the best retention rate in the groups of AxSpa women (95%, 95% CI 93–97%) and PsA men (89%, 95% CI 84–93%), with the worst retention in PsA women (66%, 95% CI 54–79%). The J48 predicted secukinumab retention with an accuracy of 77.2%. No unexpected safety issues were observed.

Conclusions: Secukinumab shows the best retention rate at 1 year of treatment in AxSpA women and in PsA men, independently of factors such as the time of disease evolution, the line of treatment or the initial dose of the drug.

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.

Anti- and non-tumor necrosis factor-α-targeted therapies effects on insulin resistance in rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis

In addition to β-cell failure with inadequate insulin secretion, the crucial mechanism leading to establishment of diabetes mellitus (DM) is the resistance of target cells to insulin, i.e. insulin resistance (IR), indicating a requirement of beyond-normal insulin concentrations to maintain euglycemic status and an ineffective strength of transduction signaling from the receptor, downstream to the substrates of insulin action. IR is a common feature of most metabolic disorders, particularly type II DM as well as some cases of type I DM. A variety of human inflammatory disorders with increased levels of proinflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, have been reported to be associated with an increased risk of IR. Autoimmune-mediated arthritis conditions, including rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS), with the involvement of proinflammatory cytokines as their central pathogenesis, have been demonstrated to be associated with IR, especially during the active disease state. There is an increasing trend towards using biologic agents and small molecule-targeted drugs to treat such disorders. In this review, we focus on the effects of anti-TNF-α- and non-TNF-α-targeted therapies on IR in patients with RA, PsA and AS. Anti-TNF-α therapy, IL-1 blockade, IL-6 antagonist, Janus kinase inhibitor and phospho-diesterase type 4 blocker can reduce IR and improve diabetic hyper-glycemia in autoimmune-mediated arthritis.

Adipose tissue inflammation and metabolic dysfunction in obesity

Several lines of preclinical and clinical research have confirmed that chronic low-grade inflammation of adipose tissue is mechanistically linked to metabolic disease and organ tissue complications in the overweight and obese organism. Despite this widely confirmed paradigm, numerous open questions and knowledge gaps remain to be investigated. This is mainly due to the intricately intertwined cross-talk of various pro- and anti-inflammatory signaling cascades involved in the immune response of expanding adipose depots, particularly the visceral adipose tissue. Adipose tissue inflammation is initiated and sustained over time by dysfunctional adipocytes that secrete inflammatory adipokines and by infiltration of bone marrow-derived immune cells that signal via production of cytokines and chemokines. Despite its low-grade nature, adipose tissue inflammation negatively impacts remote organ function, a phenomenon that is considered causative of the complications of obesity. The aim of this review is to broadly present an overview of adipose tissue inflammation by highlighting the most recent reports in the scientific literature and summarizing our overall understanding of the field. We also discuss key endogenous anti-inflammatory mediators and analyze their mechanistic role(s) in the pathogenesis and treatment of adipose tissue inflammation. In doing so, we hope to stimulate studies to uncover novel physiological, cellular, and molecular targets for the treatment of obesity.

The multi-biomarker disease activity test for assessing response to treatment strategies using methotrexate with or without prednisone in the CAMERA-II trial

Objectives

The CAMERA-II trial compared two tight-control, treat-to-target strategies, initiating methotrexate with prednisone (MTX+pred) or MTX with placebo (MTX+plac), in early RA-patients. The multi-biomarker disease activity (MBDA) blood test objectively measures RA disease activity with a score of 1–100. In CAMERA-II, response profiles of the MBDA score, its individual biomarkers, and DAS28 were assessed.

Methods

We evaluated 92 patients from CAMERA-II of whom clinical data and serum for MBDA testing at baseline and ≥ 1 time-point from months 1, 2, 3, 4, 5, 6, 9, or 12 were available. Changes (∆) from baseline for DAS28 and MBDA score and comparisons of ∆DAS28 and ∆MBDA score over time within the MTX+pred versus the MTX+plac strategy were tested for significance with t tests. Changes in biomarker concentration from baseline to months 1–5 were tested with Wilcoxon signed rank test and tested for difference between treatment arms by Mann-Whitney U test.

Results

MBDA and DAS28 showed similar response profiles, with gradual improvement over the first 6 months in the MTX+plac group, and in the MTX+pred group faster improvement during month 1, followed by gradual improvement. The 12 MBDA biomarkers could be grouped into 4 categories of response profiles, with significant responses for 4 biomarkers during the MTX+plac strategy and 9 biomarkers during the MTX+pred strategy.

Conclusions

MBDA tracked treatment response in CAMERA-II similarly to DAS28. More individual MBDA biomarkers tracked treatment response to MTX+pred than to MTX+plac. Four response profiles could be observed.

Trial registration

CAMERA-II International Standard Randomised Controlled Trial Number: ISRCTN 70365169. Registered on 29 March 2006, retrospectively registered.

Interleukin-6 receptor blockade or TNFα inhibition for reducing glycaemia in patients with RA and diabetes: post hoc analyses of three randomised, controlled trials

Background

Diabetes is common in patients with rheumatoid arthritis (RA). Interleukin (IL)-6 is implicated in both the pathogenesis of RA and in glucose homeostasis; this post hoc analysis investigated the effects of IL-6 receptor vs. tumour necrosis factor inhibition on glycosylated haemoglobin (HbA1c) in patients with RA with or without diabetes.

Methods

Data were from two placebo-controlled phase III studies of subcutaneous sarilumab 150/200 mg q2w + methotrexate or conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and a phase III monotherapy study of sarilumab 200 mg q2w vs. adalimumab 40 mg q2w. Patients with diabetes were identified by medical history or use of antidiabetic medication (patients with HbA1c ≥ 9% were excluded from all three studies). HbA1c was measured at baseline and weeks 12/24. Safety and efficacy were assessed in RA patients with or without diabetes.

Results

Patients with diabetes (n = 184) were older, weighed more and exhibited higher RA disease activity than patients without diabetes (n = 1928). Regardless of diabetes status, in patients on background csDMARDs, least squares (LS) mean difference (95% CI) in change from baseline in HbA1c for sarilumab 150 mg/200 mg vs. placebo at week 24 was − 0.28 (− 0.40, − 0.16; nominal p <  0.0001) and − 0.42 (− 0.54, − 0.31; nominal p <  0.0001), respectively. Without csDMARDs, LS mean difference for sarilumab 200 mg vs. adalimumab 40 mg at week 24 was − 0.13 (− 0.22, − 0.04; nominal p = 0.0043). Greater reduction in HbA1c than placebo or adalimumab was observed at week 24 with sarilumab in patients with diabetes and/or baseline HbA1c ≥ 7%. There was no correlation between baseline/change from baseline in HbA1c and baseline/change from baseline in C-reactive protein, 28-joint Disease Activity Score, or haemoglobin, nor between HbA1c change from baseline and baseline glucocorticoid use. Medical history of diabetes or use of diabetes treatments had limited impact on safety and efficacy of sarilumab and was consistent with overall phase III findings in patients with RA.

Conclusions

In post hoc analyses, sarilumab was associated with a greater reduction in HbA1c than csDMARDs or adalimumab, independent of sarilumab anti-inflammatory effects. Prospective studies are required to further assess these preliminary findings.

Trial registration

ClinTrials.gov NCT01061736: date of registration February 03, 2010; ClinTrials.gov NCT01709578: date of registration October 18, 2012; ClinTrials.gov NCT02332590: date of registration January 07, 2015.

Recombinant Soluble TNF-α Receptor Fusion Protein Therapy Reduces Insulin Resistance in Non-Diabetic Active Rheumatoid Arthritis Patients

Objective

Current evidence highlights a link between insulin resistance (IR) and disease activity in rheumatoid arthritis (RA), suggesting that insulin sensitivity can be improved by treating patients with TNF‐α blockers. Although reduced IR has been shown in RA patients who receive monoclonal antibody treatment, the efficacy remains to be elucidated when using recombinant soluble receptor fusion proteins. In particular, etanercept (ETA) is capable of blocking lymphotoxin‐α, a cytokine‐related to IR‐associated disease status.

Methods

A prospective study was carried out in nondiabetic active RA patients receiving a 25‐mg subcutaneous ETA injection twice weekly.

Results

Thirty patients aged 31 to 73 years (50.9 ± 10.6), naïve to biological and targeted synthetic disease‐modifying antirheumatic drugs with DAS28 scores of 5.17 to 7.49 (6.11 ± 0.66), were classified into high‐IR and low‐IR groups based on their baseline homeostatic model assessment (HOMA)‐IR levels. No differences were found between the two groups in terms of age, sex, weight, body mass index, seropositivity, and medication profiles before the injection. After a 24‐week therapeutic period, there were reduced HOMA‐IR levels in all patients in the high‐IR group (3.390 ± 0.636 to 2.234 ± 0.870, P < 0.001). A greater decrease in DAS28 values was found in patients with reduced IR than those without a reduction (2.54 ± 0.67 versus 1.46 ± 0.46, P = 0.006) in the low‐IR group.

Conclusion

We observed an improvement in insulin sensitivity in nondiabetic active RA patients following 24‐week recombinant soluble TNF‐α receptor fusion protein therapy.

Impact of TNF-α Inhibitors on Body Weight and BMI: A Systematic Review and Meta-Analysis

Objective

The aim of this systematic review and meta-analysis of longitudinal studies was to ascertain to effects of TNF-α inhibitor therapy on body weight and BMI.

Methods

Three databases (PubMed, OVID, and EMBASE) were systematically searched from inception to August 2018. We identified prospective, retrospective, and randomized controlled studies in adults with immune-mediated inflammatory diseases treated with TNF-α inhibitors based on pre-specified inclusion criteria. A random-effects model was used to estimate standardised mean change (SMCC).

Results

Twenty-six longitudinal studies with a total of 1,245 participants were included in the meta-analysis. We found evidence for a small increase in body weight (SMCC = 0.24, p = .0006, 95% CI [0.10, 0.37]) and in BMI (SMCC = 0.26, p < .0001, 95% CI [0.13, 0.39]). On average, patients gained 0.90kg (SD = 5.13) under infliximab, 2.34kg (D = 5.65) under etanercept and 2.27kg (SD = 4.69) during treatment with adalimumab within the duration of the respective studies (4–104 weeks).

Conclusion

Our results yield further support the for the view that TNF-α inhibitors increase body weight and BMI as a potential side effect. Modulating cytokine signaling could be a future therapeutic mechanism to treat disorders associated with weight changes such as anorexia nervosa.

Characterization and Treatment of Inflammation and Insulin Resistance in Obese Adipose Tissue

Adipose tissue is the largest energy storage and protection organ. It is distributed subcutaneously and around the internal organs. It regulates metabolism by storing and releasing fatty acids and secreting adipokines. Excessive nutritional intake results in adipocyte hypertrophy and proliferation, leading to local hypoxia in adipose tissue and changes in the release of adipokines. These lead to recruit of more immune cells into adipose tissue and release of inflammatory signaling factors. Excess free fatty acids and inflammatory factors interfere with intracellular insulin signaling. In this review, we summarize the characteristics of obese adipose tissue and analyze how its inflammation causes insulin resistance. We further discuss the latest clinical research progress on the control of insulin resistance and inflammation resulting from obesity through anti-inflammatory therapy and bariatric surgery. Our review shows that targeted anti-inflammatory therapy is of great significance for obese patients with insulin resistance.

Pathobiological mechanisms underlying metabolic syndrome (MetS) in chronic obstructive pulmonary disease (COPD): clinical significance and therapeutic strategies

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and is currently the 4th largest cause of death in the world. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities (e.g. skeletal muscle wasting, ischemic heart disease, cognitive dysfunction) and infective viral and bacterial acute exacerbations (AECOPD). Current pharmacological treatments for COPD are relatively ineffective and the development of effective therapies has been severely hampered by the lack of understanding of the mechanisms and mediators underlying COPD. Since comorbidities have a tremendous impact on the prognosis and severity of COPD, the 2015 American Thoracic Society/European Respiratory Society (ATS/ERS) Research Statement on COPD urgently called for studies to elucidate the pathobiological mechanisms linking COPD to its comorbidities. It is now emerging that up to 50% of COPD patients have metabolic syndrome (MetS) as a comorbidity. It is currently not clear whether metabolic syndrome is an independent co-existing condition or a direct consequence of the progressive lung pathology in COPD patients. As MetS has important clinical implications on COPD outcomes, identification of disease mechanisms linking COPD to MetS is the key to effective therapy. In this comprehensive review, we discuss the potential mechanisms linking MetS to COPD and hence plausible therapeutic strategies to treat this debilitating comorbidity of COPD.

IgG Anti-ghrelin Immune Complexes Are Increased in Rheumatoid Arthritis Patients Under Biologic Therapy and Are Related to Clinical and Metabolic Markers

Rheumatoid arthritis (RA) is a systemic autoimmune disease associated with increased risk of cardiovascular disease and metabolic alterations. The mechanisms underlying these alterations remain unclear. Ghrelin is a gastrointestinal hormone with potent effects on food intake, body weight, metabolism, and immune response. Recent studies reported the presence of anti-ghrelin autoantibodies in healthy subjects and the levels and affinity of these autoantibodies were altered in anorectic and obese individuals. In this cross-sectional study we analyzed anti-ghrelin autoantibodies in RA patients and evaluated its relationship with clinical, body-composition and metabolic parameters. Clinical measurements of RA patients included the disease activity score-28 (DAS-28), inflammatory biomarkers, autoantibodies (RF and anti-CCP), body composition, glucose and lipid profile. Serum ghrelin levels were measured by enzyme-linked immunosorbent assay (ELISA). Free and total anti-ghrelin autoantibodies quantification (IgG and IgA isotypes) was performed by in-house ELISA. RA patients had lower IgG anti-ghrelin autoantibodies levels and higher immune complexes percentage (IgG+ghrelin) compared to the control group, while the IgA anti-ghrelin autoantibodies showed no significant differences. In the bivariate analysis, the percentage of IgG anti-ghrelin immune complexes positively correlated with BMI and ghrelin whereas in the multivariate regression model, the variables associated were DAS-28, body weight, visceral fat, LDL-C and TG (R ² = 0.72). The percentage of IgA anti-ghrelin immune complexes positively correlated with RF and anti-CCP and the multivariate regression model showed an association with RF and body fat percentage (R ² = 0.22). Our study shows an increased percentage of IgG anti-ghrelin immune complexes in RA patients despite ghrelin levels were similar in both groups, suggesting an increase in the affinity of these autoantibodies toward ghrelin. The associations found in the multiple regression analysis for anti-ghrelin immune complexes support the previously reported functions of these natural autoantibodies as carriers and modulators of the stability and physiological effect of the hormone. However, in RA both the disease activity and the RF appear to influence the formation of these anti-ghrelin immune complexes.

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.

Regulation of Metabolic Disease-Associated Inflammation by Nutrient Sensors

Visceral obesity is frequently associated with the development of type 2 diabetes (T2D), a highly prevalent chronic disease that features insulin resistance and pancreatic β-cell dysfunction as important hallmarks. Recent evidence indicates that the chronic, low-grade inflammation commonly associated with visceral obesity plays a major role connecting the excessive visceral fat deposition with the development of insulin resistance and pancreatic β-cell dysfunction. Herein, we review the mechanisms by which nutrients modulate obesity-associated inflammation.

Curcumin Suppresses IL-1β Secretion and Prevents Inflammation through Inhibition of the NLRP3 Inflammasome

Turmeric is traditionally used as a spice and coloring in foods. Curcumin is the primary active ingredient in the turmeric, and compelling evidence has shown that it has the ability to inhibit inflammation. However, the mechanism mediating its anti-inflammatory effects are not fully understood. We report that curcumin inhibited caspase-1 activation and IL-1β secretion through suppressing LPS priming and the inflammasome activation pathway in mouse bone marrow-derived macrophages. The inhibitory effect of curcumin on inflammasome activation was specific to the NLRP3, not to the NLRC4 or the AIM2 inflammasomes. Curcumin inhibited the NLRP3 inflammasome by preventing K⁺ efflux and disturbing the downstream events, including the efficient spatial arrangement of mitochondria, ASC oligomerization, and speckle formation. Reactive oxygen species, autophagy, sirtuin-2, or acetylated α-tubulin was ruled out as the mechanism by which curcumin inhibits the inflammasome. Importantly, in vivo data show that curcumin attenuated IL-1β secretion and prevented high-fat diet-induced insulin resistance in wide-type C57BL/6 mice but not in Nlrp3-deficient mice. Curcumin also repressed monosodium urate crystal-induced peritoneal inflammation in vivo. Taken together, we identified curcumin as a common NLRP3 inflammasome activation inhibitor. Our findings reveal a mechanism through which curcumin represses inflammation and suggest the potential clinical use of curcumin in NLRP3-driven diseases.

Angiopoietin-like 4: A molecular link between insulin resistance and rheumatoid arthritis

Recent evidence suggests that common factor(s) or molecule(s) might regulate lipid and glucose metabolism, inflammation, and bone and cartilage degeneration. These findings may be particularly relevant for cases of rheumatoid arthritis, in which chronic inflammation occurs in an autoimmune context and causes the degradation of articular joints as well as insulin resistance and cardiovascular complications. Candidates for this common regulatory system include signals mediated by peroxisome proliferator-activated regulator and its response factor, angiopoietin-like 4. The expression and bioactivity of angiopoietin-like 4, an adipocytokine that was originally reported to have an angiogenic function, have been detected not only in the vascular system and adipose tissue but also in rheumatoid joints. An essential role for angiopoietin-like 4 has been established in dyslipidemia, and recent reports indicate that it may modulate bone and cartilage catabolism in rheumatoid arthritis. The enhanced expression of angiopoietin-like 4 in rheumatoid arthritis may explain the occurrence of insulin resistance, cardiovascular risk, and joint destruction, thereby suggesting that this molecule could be a potential target for anti-rheumatoid arthritis strategies. This review describes recent research on the role of angiopoietin-like 4 in chronic inflammatory conditions and rheumatoid arthritis, as well as potential therapeutic candidates. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:939-943, 2017.

Obesity is the main determinant of insulin resistance more than the circulating pro-inflammatory cytokines levels in rheumatoid arthritis patients

BACKGROUND

Systemic blockade of TNF-α in Rheumatoid arthritis with insulin resistance seems to produce more improvement in insulin sensitivity in normal weight patients with Rheumatoid arthritis than in obese patients with Rheumatoid arthritis, suggesting that systemic-inflammation and obesity are independent risk factors for insulin resistance in Rheumatoid arthritis patients.

OBJECTIVES

To evaluate the insulin resistance in: normal weight patients with Rheumatoid arthritis, overweight patients with Rheumatoid arthritis, obese Rheumatoid arthritis patients, and matched control subjects with normal weight and obesity; and its association with major cytokines involved in the pathogenesis of the disease.

METHODS

Assessments included: body mass index, insulin resistance by Homeostasis Model Assessment, ELISA method, and enzymatic colorimetric assay.

RESULTS

Outstanding results from these studies include: (1) In Rheumatoid arthritis patients, insulin resistance was well correlated with body mass index, but not with levels of serum cytokines. In fact, levels of cytokines were similar in all Rheumatoid arthritis patients, regardless of being obese, overweight or normal weight (2) Insulin resistance was significantly higher in Rheumatoid arthritis with normal weight than in normal weight (3) No significant difference was observed between insulin resistances of Rheumatoid arthritis with obesity and obesity (4) As expected, levels of circulating cytokines were significantly higher in Rheumatoid arthritis patients than in obesity.

CONCLUSIONS

Obesity appears to be a dominant condition above inflammation to produce IR in RA patients. The dissociation of the inflammation and obesity components to produce IR suggests the need of an independent therapeutic strategy in obese patients with RA.

Resistin Gene Expression is Downregulated in CD4(+) T Helper Lymphocytes and CD14(+) Monocytes in Rheumatoid Arthritis Responding to TNF-α Inhibition

Rheumatoid arthritis (RA) is caused by complex interactions between immune cells and sustained by Th1 response cytokines. Resistin [resistance to insulin; (RETN)] is an inflammatory cytokine, first discovered in murine adipocytes. In man, RETN is mainly secreted by monocytes. The distinct role of RETN in the immune reaction is uncertain; however, RETN has pro-inflammatory, pro-fibrotic and possibly tolerogenic properties. The aim was to assess the reaction of RETN gene expression to TNF-α inhibition (I) in pathogenetic immune cell subsets in RA, in the context of Th1, inflammatory and regulatory cytokine gene expressions. Accordingly, we measured RETN, IFN-γ, TNF-β, IL-1β, TNF-α, TGF-β and IL-10 gene expressions in CD14(+) monocytes, CD4(+) T helper (Th) lymphocytes (ly), CD8(+) T cytotoxic (Tc) ly and CD19(+) B ly in active RA before and 3 months after start of TNF-αI. Leucocyte subsets were separated by specific monoclonal antibody-covered beads, RNA extracted and levels of RETN, Th1 response, inflammatory and regulatory cytokine mRNAs measured by quantitative reverse transcription-polymerase chain reaction technique. We found that TNF-αI caused a significant downregulation of RETN gene expression in CD14(+) monocytes and CD4(+) Th ly and was unchanged in CD8(+) Tc ly and CD19(+) B ly. Both in active RA and during TNF-αI, RETN mRNA levels were significantly higher in CD14(+) monocytes than in all other examined cell types. In monocytes, fold change in RETN and TGF-β gene expressions upon TNF-αI correlated significantly. Our findings indicate that RETN has pro-inflammatory as well as proresolving roles in active RA.

Nonalcoholic fatty liver disease: one entity, multiple impacts on liver health

Nonalcoholic fatty liver disease (NAFLD) is very prevalent and now considered the most common cause of chronic liver disease. Staging the severity of liver damage is very important because the prognosis of NAFLD is highly variable. The long-term prognosis of patients with NAFLD remains incompletely elucidated. Even though the annual fibrosis progression rate is significantly higher in patients with nonalcoholic hepatitis (NASH), both types of NAFLD (nonalcoholic fatty liver and nonalcoholic steatohepatitis) can lead to fibrosis. The risk for progressive liver damage and poor outcomes is assessed by staging the severity of liver injury and liver fibrosis. Algorithms (scores) that incorporate various standard clinical and laboratory parameters alongside imaging-based approaches that assess liver stiffness are helpful in predicting advanced fibrosis.

Improvement in insulin resistance is greater when infliximab is added to methotrexate during intensive treatment of early rheumatoid arthritis-results from the IDEA study

OBJECTIVES

To determine the change in established biomarkers of cardiovascular (CV) risk, namely, total cholesterol/high-density lipoprotein cholesterol ratio (TC/HDL-C), N-terminal pro-brain natriuretic peptide (NT-proBNP) and insulin resistance (IR) in patients with early RA treated with two different treat-to-target strategies.

METHODS

Fasting glucose, lipids, insulin and NT-proBNP were measured at baseline, weeks 26 and 78 in 79 DMARD-naïve RA patients, free of CV disease, as part of a double-blind randomized controlled trial of MTX with either infliximab (IFX) or methylprednisolone as induction therapy. Homeostasis model assessment-estimated IR (HOMA-IR) (glucose*insulin/405) was used to measure IR. Multiple imputation was employed, and linear regression analyses were adjusted for baseline values.

RESULTS

Changes in DAS44-CRP did not differ between the treatment arms at weeks 26 and 78. Mean TC/HDL-C, HOMA-IR and NT-proBNP improved in both groups at weeks 26 and 78, although change in NT-proBNP was not statistically significant at week 78. Changes in TC/HDL-C and NT-proBNP were similar between treatment arms, but HOMA-IR values in the IFX + MTX arm were 42% lower than those treated with MTX + methylprednisolone at week 78 (P = 0.003); the difference remained significant after adjustment for baseline BMI, ACPA positivity, smoking status and intramuscular glucocorticoid use (P = 0.007).

CONCLUSION

When implementing a treat-to-target approach, treatment of early RA was associated with improvement in TC/HDL-C, HOMA-IR and NT-proBNP, and a greater long-term improvement in HOMA-IR was seen in those treated with IFX.

TRIAL REGISTRATION

EU Clinical Trials Register, http://www.clinicaltrialsregister.eu, Eudract-2005-005013-37; ISRTCNregisrty, http://www.isrctn.com, ISRCTN48638981.

Psoriasis, non-alcoholic fatty liver disease, and cardiovascular disease: Three different diseases on a unique background

Psoriasis is a chronic inflammatory immune-mediated skin disease, frequently associated with systemic comorbidities. According to recent data, patients with psoriasis show a greater prevalence of metabolic syndrome, which confers a higher cardiovascular risk. The link between these pathological conditions appears to be a chronic low-grade inflammatory status. The aim of this review is to focus on the multiple epidemiological and physio-pathogenetic aspects linking non-alcoholic fatty liver disease, psoriasis, and cardiovascular disease.

The relationship between body weight and inflammation: Lesson from anti-TNF-α antibody therapy

Obesity is associated with many pathological conditions. Tumor Necrosis Factor-α (TNF-α) is one of the key mediators of inflammation involved in the obesity-related insulin resistance development. We aim to review the human evidence useful to clarify the relationship between inflammation and body weight, with particular reference to TNF-α. Genetic polymorphisms and epigenetic factors, such as diet, could affect TNF-α activity. TNF-α is associated with obesity, but also with anorexia and cachexia. Despite the role of TNF-α in obesity-related diseases, anti-TNF-α antibody therapy is associated with an increase in adiposity. In conclusion the reviewed results suggest that inflammation is more likely a consequence rather than a cause of obesity.

Evidence-based Recommendations for the Management of Comorbidities in Rheumatoid Arthritis, Psoriasis, and Psoriatic Arthritis: Expert Opinion of the Canadian Dermatology-Rheumatology Comorbidity Initiative

Objective.

Comorbidities such as cardiovascular diseases (CVD), cancer, osteoporosis, and depression are often underrecognized in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), or psoriasis (PsO). Recommendations may improve identification and treatment of comorbidities. The Canadian Dermatology-Rheumatology Comorbidity Initiative reviewed the literature to develop practical evidence-based recommendations for management of comorbidities in patients with RA, PsA, and PsO.

Methods.

Eight main topics regarding comorbidities in RA, PsA, and PsO were developed. MEDLINE, EMBASE, and the Cochrane Library (1960–12/2012), together with abstracts from major rheumatology and dermatology congresses (2010–2012), were searched for relevant publications. Selected articles were analyzed and metaanalyses performed whenever possible. A meeting including rheumatologists, dermatologists, trainees/fellows, and invited experts was held to develop consensus-based recommendations using a Delphi process with prespecified cutoff agreement. Level of agreement was measured using a 10-point Likert scale (1 = no agreement, 10 = full agreement) and the potential effect of recommendations on daily clinical practice was considered. Grade of recommendation (ranging from A to D) was determined according to the Oxford Centre for Evidence-Based Medicine evidence levels.

Results.

A total of 17,575 articles were identified, of which 407 were reviewed. Recommendations were synthesized into 19 final recommendations ranging mainly from grade C to D, and relating to a large spectrum of comorbidities observed in clinical practice: CVD, obesity, osteoporosis, depression, infections, and cancer. Level of agreement ranged from 80.9% to 95.8%.

Conclusion.

These practical evidence-based recommendations can guide management of comorbidities in patients with RA, PsA, and PsO and optimize outcomes.

Effects of Tumour Necrosis Factor Antagonists on Insulin Sensitivity/Resistance in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

Beyond the joints, TNFi (tumour necrosis factor inhibitor) therapy may confer systemic benefits in rheumatoid arthritis (RA). Several studies have investigated the role of TNFi on insulin resistance/sensitivity (IR/IS). This question is of general interest given the emerging evidence linking inflammation and insulin resistance. The main aim of this review was to summarise the published data and to determine the effects of TNFi on IR/IS.

METHODS

We searched the PubMed and ISI Web of Knowledge databases for studies which examined the effects of TNFi on IR/IS. The studies were assessed independently by two reviewers according to a pre-specified protocol. The data on Homeostatic Model Assessment for Insulin resistance (HOMA) and Quantitative Insulin Sensitivity Check Index (QUICKI) were pooled and reported as standard difference in means (SDM) with 95% confidence interval (CI) using a random-effects model.

RESULTS

A total of eight studies with 260 subjects met the selection criteria. The duration of the studies was from 8 weeks to 12 months. There was statistically significant reduction in HOMA index in six out of eight studies and four reported significant increment in QUICKI. The pooled analysis revealed significant reduction in HOMA [SDM-0.148, 95%CI[-0.278 to -0.017], p=0.026] and increment in QUICKI [SDM 0.312, 95%CI[0.019 to 0.606], p=0.037] with TNFi.

CONCLUSION

There is emerging evidence to support that TNFi therapy improves IS and reduces IR in RA. Further, well conducted trials are needed to determine if such effects translate to lower incidence of diabetes in RA or other autoimmune conditions on biologic therapy.

Anti-inflammatory agents to treat or prevent type 2 diabetes, metabolic syndrome and cardiovascular disease

INTRODUCTION

There is a growing body of evidence to suggest that chronic silent inflammation is a key feature in abdominal obesity, metabolic syndrome, type 2 diabetes (T2DM) and cardiovascular disease (CVD). These observations suggest that pharmacological strategies, which reduce inflammation, may be therapeutically useful in treating obesity, type 2 diabetes and associated CVD.

AREA COVERED

The article covers novel strategies, using either small molecules or monoclonal antibodies. These strategies include: approaches targeting IKK-b-NF-kB (salicylates, salsalate), TNF-α (etanercept, infliximab, adalimumab), IL-1β (anakinra, canakinumab) and IL-6 (tocilizumab), AMP-activated protein kinase activators, sirtuin-1 activators, mammalian target of rapamycin inhibitors and C-C motif chemokine receptor 2 antagonists.

EXPERT OPINION

The available data supports the concept that targeting inflammation improves insulin sensitivity and β-cell function; it also ameliorates glucose control in insulin-resistant patients with inflammatory rheumatoid diseases as well in patients with metabolic syndrome or T2DM. Although promising, the observed metabolic effects remain rather modest in most clinical trials. The potential use of combined anti-inflammatory agents targeting both insulin resistance and insulin secretion appears appealing but remains unexplored. Large-scale prospective clinical trials are underway to investigate the safety and efficacy of different anti-inflammatory drugs. Further evidence is needed to support the concept that targeting inflammation pathways may represent a valuable option to tackle the cardiometabolic complications of obesity.

Metabolic syndrome and its components in patients with psoriasis

Psoriasis is a chronic inflammatory disease of the skin which affects 1-3% of the population. A higher association of metabolic syndrome (MS) has been described amongst sufferers. The objective of this study was to assess the association of MS and its components amongst subjects suffering psoriasis and compare it with that found for the control group. The secondary objective was to study the relationship between the duration and severity of the psoriasis and the MS. This was a case–control study: 102 subjects with psoriasis and 102 control subjects paired by sex, age and body mass index. Anamnesis: history of diabetes mellitus, arterial hypertension, dyslipidaemia and psoriasis. Lifestyle. Physical examination: weight, height, blood pressure, waist circumference. Tests: lipid profile, oral glucose tolerance test and insulinemia (HOMA calculation). MS classified according to the 2009 consensus. The prevalence of MS amongst psoriasis patients was 52.9%, as compared to 34.31% in the control group. MS independent factors: age (OR 1.085), body mass index (OR 1.346), sex (OR 2.69 for men) and psoriasis (OR 3.634). A comparative study of patients with psoriasis with or without MS, revealed no relationship to the severity, age at time of diagnosis or time of evolution of the psoriasis. In conclusion, the association of MS amongst psoriasis sufferers is very high and the disease is considered as an independent risk factor for MS. Our results show no relationship between the different characteristics of psoriasis and the presence of MS. The main limitation of this study is that it does not enable to conclude whether psoriasis is a risk factor for MS or the opposite.

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.

Biomarkers of psoriasis severity and therapy monitoring

Psoriasis is a chronic, recurrent inflammatory cutaneous disease. Psoriasis patients alternate between periods of remission and periods of exacerbation of the disease. Usually, psoriasis severity is clinically evaluated using tools like Psoriasis Area and Severity Index that present some limitations and subjectivity. Clinicians select the therapy according to psoriasis severity, aiming that patients achieve longer remission periods and improve their quality of life. Biological markers for diagnosis and prognosis of psoriasis help to establish its severity and to monitor the therapeutic response; moreover, biomarkers of psoriasis assist clinicians in their therapeutic decision to treat psoriasis and to choose earlier and more adequate therapeutic strategies, avoiding or minimising worsening of psoriasis. With these markers, they would be able to monitor therapeutics, avoiding unnecessary therapeutic surcharge or changes to a more aggressive therapy. As any attempt to identify these biomarkers should be encouraged, in this review, we will debate published data concerning the proposal of biomarkers to evaluate severity and response to treatment of psoriasis vulgaris.

Role of innate immune response in non-alcoholic Fatty liver disease: metabolic complications and therapeutic tools

Non-alcoholic fatty liver disease (NAFLD) is currently the most common liver disease worldwide, both in adults and children. It is characterized by an aberrant lipid storage in hepatocytes, named hepatic steatosis. Simple steatosis remains a benign process in most affected patients, while some of them develop superimposed necroinflammatory activity with a non-specific inflammatory infiltrate and a progression to non-alcoholic steatohepatitis with or without fibrosis. Deep similarity and interconnections between innate immune cells and those of liver parenchyma have been highlighted and showed to play a key role in the development of chronic liver disease. The liver can be considered as an “immune organ” because it hosts non-lymphoid cells, such as macrophage Kupffer cells, stellate and dendritic cells, and lymphoid cells. Many of these cells are components of the classic innate immune system, enabling the liver to play a major role in response to pathogens. Although the liver provides a “tolerogenic” environment, aberrant activation of innate immune signaling may trigger “harmful” inflammation that contributes to tissue injury, fibrosis, and carcinogenesis. Pathogen recognition receptors, such as toll-like receptors and nucleotide oligomerization domain-like receptors, are responsible for the recognition of immunogenic signals, and represent the major conduit for sensing hepatic and non-hepatic noxious stimuli. A pivotal role in liver inflammation is also played by cytokines, which can initiate or have a part in immune response, triggering hepatic intracellular signaling pathways. The sum of inflammatory signals and deranged substrate handling induce most of the metabolic alteration traits: insulin resistance, obesity, diabetes, hyperlipidemia, and their compounded combined effects. In this review, we discuss the relevant role of innate immune cell activation in relation to NAFLD, the metabolic complications associated to this pathology, and the possible pharmacological tools.

Adipokines, biomarkers of endothelial activation, and metabolic syndrome in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease associated with accelerated atherosclerosis and increased risk of cardiovascular (CV) disease. AS patients also display a high prevalence of features clustered under the name of metabolic syndrome (MeS). Anti-TNF-α therapy was found to be effective to treat AS patients by suppressing inflammation and also improving endothelial function. Previously, it was demonstrated that a short infusion of anti-TNF-α monoclonal antibodyinfliximab induced a rapid and dramatic reduction in serum insulin levels and insulin resistance along with a rapid improvement of insulin sensitivity in nondiabetic AS patients. The role of adipokines, MeS-related biomarkers and biomarkers of endothelial cell activation and inflammation seem to be relevant in different chronic inflammatory diseases. However, its implication in AS has not been fully established. Therefore, in this review we summarize the recent advances in the study of the involvement of these molecules in CV disease or MeS in AS. The assessment of adipokines and biomarkers of endothelial cell activation and MeS may be of potential relevance in the stratification of the CV risk of patients with AS.

Direct effects of TNF-α on local fuel metabolism and cytokine levels in the placebo-controlled, bilaterally infused human leg: increased insulin sensitivity, increased net protein breakdown, and increased IL-6 release

Tumor necrosis factor-α (TNF-α) has widespread metabolic actions. Systemic TNF-α administration, however, generates a complex hormonal and metabolic response. Our study was designed to test whether regional, placebo-controlled TNF-α infusion directly affects insulin resistance and protein breakdown. We studied eight healthy volunteers once with bilateral femoral vein and artery catheters during a 3-h basal period and a 3-h hyperinsulinemic-euglycemic clamp. One artery was perfused with saline and one with TNF-α. During the clamp, TNF-α perfusion increased glucose arteriovenous differences (0.91 ± 0.17 vs. 0.74 ± 0.15 mmol/L, P = 0.012) and leg glucose uptake rates. Net phenylalanine release was increased by TNF-α perfusion with concomitant increases in appearance and disappearance rates. Free fatty acid kinetics was not affected by TNF-α, whereas interleukin-6 (IL-6) release increased. Insulin and protein signaling in muscle biopsies was not affected by TNF-α. TNF-α directly increased net muscle protein loss, which may contribute to cachexia and general protein loss during severe illness. The finding of increased insulin sensitivity, which could relate to IL-6, is of major clinical interest and may concurrently act to provide adequate tissue fuel supply and contribute to the occurrence of systemic hypoglycemia. This distinct metabolic feature places TNF-α among the rare insulin mimetics of human origin.

Immune mechanisms in atherosclerosis, especially in diabetes type 2

Atherosclerosis and ensuing cardiovascular disease (CVD) are major complications of diabetes type 2. Atherosclerosis is a chronic inflammatory condition involving immunocompetent cells of different types present in the lesions. Even though inflammation and immune activation may be more pronounced in atherosclerosis in diabetes type 2, there does not appear to be any major differences between diabetics and non-diabetics. Similar factors are thus implicated in atherosclerosis-associated immune activation in both groups. The cause of immune activation is not known and different mutually non-exclusive possibilities exist. Oxidized and/or enzymatically modified forms of low-density lipoprotein (OxLDL) and dead cells are present in atherosclerotic plaques. OxLDL could play a role, being pro-inflammatory and immunostimulatory as it activates T-cells and is cytotoxic at higher concentrations. Inflammatory phospholipids in OxLDL are implicated, with phosphorylcholine (PC) as one of the exposed antigens. Antibodies against PC (anti-PC) are anti-atherogenic in mouse studies, and anti-PC is negatively associated with development of atherosclerosis and CVD in humans. Bacteria and virus have been discussed as potential causes of immune activation, but it has been difficult to find direct evidence supporting this hypothesis, and antibiotic trials in humans have been negative or inconclusive. Heat shock proteins (HSP) could be one major target for atherogenic immune reactions. More direct causes of plaque rupture include cytokines such as interleukin 1β (IL-1β), tumor necrosis factor (TNF), and also lipid mediators as leukotrienes. In addition, in diabetes, hyperglycemia and oxidative stress appear to accelerate the development of atherosclerosis, one mechanism could be via promotion of immune reactions. To prove that immune reactions are causative of atherosclerosis and CVD, further studies with immune-modulatory treatments are needed.

Cardiovascular Comorbidities of Psoriasis and Psoriatic Arthritis: A Report from the GRAPPA 2012 Annual Meeting

At the 2012 annual meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) in Stockholm, Sweden, several GRAPPA members led a panel discussion on cardiovascular (CV) comorbidities of psoriasis and psoriatic arthritis (PsA). The panelists discussed the role of insulin resistance in the pathophysiology of psoriasis, the possible effect of tumor necrosis factor inhibitors on CV comorbidities, and the effect of 12/23 monoclonal antibodies on CV outcomes. The panelists also addressed how lessons from CV comorbidity research could be applied to other areas of comorbidity research in psoriasis and PsA and identified future research directions in this area.

From endocrine to rheumatism: do gut hormones play roles in rheumatoid arthritis?

RA is characterized by chronic inflammation in the musculoskeletal system, in which TNF-α is the key cytokine trigger. TNF-α, previously known as cachectin, is implicated in the modulation of body composition and energy expenditure. Gut hormones, including acyl ghrelin, des-acyl ghrelin, GIP, GLP-1 and PYY, have been known to be the major regulators of appetite, nutrition, energy expenditure and body mass formation. Emerging evidence indicates that blockade of TNF-α by biologics not only ameliorates rheumatoid inflammation, but can affect the secretion and action of gut hormones on appetite, body composition, energy expenditure, muscle catabolism and bone remodelling. A link between the gastrointestinal endocrine axis and the immune system may be established through the interaction of proinflammatory cytokines, including TNF-α and these gut hormones. With the ever-increasing understanding of rheumatoid inflammation and the invention of more biologics to modulate the cytokine network, more attention should be given to the possible immunomodulatory roles of gut hormones in autoimmune inflammatory reactions.

The vascular endothelium in diabetes--a therapeutic target?

Insulin resistance affects the vascular endothelium, and contributes to systemic insulin resistance by directly impairing the actions of insulin to redistribute blood flow as part of its normal actions driving muscle glucose uptake. Impaired vascular function is a component of the insulin resistance syndrome, and is a feature of type 2 diabetes. On this basis, the vascular endothelium has emerged as a therapeutic target where the intent is to improve systemic metabolic state by improving vascular function. We review the available literature presenting studies in humans, evaluating the effects of metabolically targeted and vascular targeted therapies on insulin action and systemic metabolism. Therapies that improve systemic insulin resistance exert strong concurrent effects to improve vascular function and vascular insulin action. RAS-acting agents and statins have widely recognized beneficial effects on vascular function but have not uniformly produced the hoped-for metabolic benefits. These observations support the notion that systemic metabolic benefits can arise from therapies targeted at the endothelium, but improving vascular insulin action does not result from all treatments that improve endothelium-dependent vasodilation. A better understanding of the mechanisms of insulin's actions in the vascular wall will advance our understanding of the specificity of these responses, and allow us to better target the vasculature for metabolic benefits.

Tumor necrosis factor-induced cerebral insulin resistance in Alzheimer's disease links numerous treatment rationales

The evident limitations of the amyloid theory of the pathogenesis of Alzheimer's disease are increasingly putting alternatives in the spotlight. We argue here that a number of independently developing approaches to therapy-including specific and nonspecific anti-tumor necrosis factor (TNF) agents, apolipoprotein E mimetics, leptin, intranasal insulin, the glucagon-like peptide-1 mimetics and glycogen synthase kinase-3 (GSK-3) antagonists-are all part of an interlocking chain of events. All these approaches inform us that inflammation and thence cerebral insulin resistance constitute the pathway on which to focus for a successful clinical outcome in treating this disease. The key link in this chain presently absent is a recognition by Alzheimer's research community of the long-neglected history of TNF induction of insulin resistance. When this is incorporated into the bigger picture, it becomes evident that the interventions we discuss are not competing alternatives but equally valid approaches to correcting different parts of the same pathway to Alzheimer's disease. These treatments can be expected to be at least additive, and conceivably synergistic, in effect. Thus the inflammation, insulin resistance, GSK-3, and mitochondrial dysfunction hypotheses are not opposing ideas but stages of the same fundamental, overarching, pathway of Alzheimer's disease pathogenesis. The insight this provides into progenitor cells, including those involved in adult neurogenesis, is a key part of this approach. This pathway also has therapeutic implications for other circumstances in which brain TNF is pathologically increased, such as stroke, traumatic brain injury, and the infectious disease encephalopathies.