Complement C3 Is the Strongest Predictor of Whole-Body Insulin Sensitivity in Psoriatic Arthritis

Beyond Systemic Lupus Erythematosus and Anti-Phospholipid Syndrome: The Relevance of Complement From Pathogenesis to Pregnancy Outcome in Other Systemic Rheumatologic Diseases

Evidence about the relevance of the complement system, a highly conserved constituent of the innate immunity response that orchestrates the elimination of pathogens and the inflammatory processes, has been recently accumulated in many different rheumatologic conditions. In rheumatoid arthritis, complement, mainly the classical pathway, contributes to tissue damage especially in seropositive subjects, with complement activation occurring in the joint. Data about complement pathways in psoriatic arthritis are dated and poorly consistent; among patients with Sjögren syndrome, hypocomplementemia exerts a prognostic role, identifying patients at risk of extra-glandular manifestations. Hints about complement involvement in systemic sclerosis have been recently raised, following the evidence of complement deposition in affected skin and in renal samples from patients with scleroderma renal crisis. In vasculitides, complement plays a dual role: on one hand, stimulation of neutrophils with anti-neutrophil cytoplasmic antibodies (ANCA) results in the activation of the alternative pathway, on the other, C5a induces translocation of ANCA antigens, favouring the detrimental role of antibodies. Complement deposition in the kidneys identifies patients with more aggressive renal disease; patients with active disease display low serum levels of C3 and C4. Even though in dermatomyositis sC5b-9 deposits are invariably present in affected muscles, data on C3 and C4 fluctuation during disease course are scarce. C3 and C1q serum levels have been explored as potential markers of disease activity in Takayasu arteritis, whereas data in Behçet disease are limited to in vitro observations. Pregnancies in women with rheumatologic conditions are still burdened by a higher rate of pregnancy complications, thus the early identification of women at risk would be invaluable. A fine-tuning of complement activation is required from a physiological progression of pregnancy, from pre-implantation stages, through placentation to labour. Complement deregulation has been implicated in several pregnancy complications, such as recurrent abortion, eclampsia and premature birth; low complement levels have been shown to reliably identify women at risk of complications. Given its physiologic role in orchestrating pregnancy progression and its involvement as pathogenic effector in several rheumatologic conditions, complement system is an attractive candidate biomarker to stratify the obstetric risk among women with rheumatologic conditions.

Prevalence of Type 2 and Type 1 Diabetes in Psoriatic Arthritis: An Italian Study

OBJECTIVE

Psoriatic arthritis (PsA) is burdened by an increased susceptibility to cardiovascular diseases. Comorbid diabetes may represent one of the key factors contributing to this risk. The aim of our medical records review study was to investigate the prevalence of type 2 diabetes (T2D) and type 1 diabetes (T1D) in an Italian PsA cohort.

METHODS

The clinical records of all patients consecutively seen at our clinic with a diagnosis of PsA during a 12-month period were reviewed to identify comorbid T2D or T1D. For comparison, a 1:1 age- and sex-matched group of individuals with noninflammatory diseases was recruited.

RESULTS

The final study cohort comprised 408 patients. The prevalence of T2D was 7.8% (95% confidence interval, 5.6-10.8) in PsA and 4.4% in controls (95% confidence interval, 2.8-6.9; p = 0.04). Two cases (0.49%) of T1D were identified in the PsA cohort, whereas no cases were observed in controls. In a multivariate logistic regression model including age, disease duration, and body mass index (BMI) as covariates, increasing age (odds ratio [OR], 1.079; p = 0.006) and BMI (OR, 1.188; p = 0.011) but not PsA duration predicted being classified as having T2D. In a similar model accounting for age and BMI, average disease activity score including 28 joints and C-reactive protein showed a trend toward significance (OR, 1.639; p = 0.066).

CONCLUSIONS

In conclusion, our data provide further support to the emerging evidence of an increased risk of T2D in PsA patients. Cardiometabolic comorbidity represents a significant aspect of integrated arthritis management to improve long-term cardiovascular outcomes and to provide a comprehensive treatment.

Insulin Signaling in Arthritis

Inflammatory arthritis is burdened by an increased risk of metabolic disorders. Cytokines and other mediators in inflammatory diseases lead to insulin resistance, diabetes and hyperlipidemia. Accumulating evidence in the field of immunometabolism suggests that the cause-effect relationship between arthritis and metabolic abnormalities might be bidirectional. Indeed, the immune response can be modulated by various factors such as environmental agents, bacterial products and hormones. Insulin is produced by pancreatic cells and regulates glucose, fat metabolism and cell growth. The action of insulin is mediated through the insulin receptor (IR), localized on the cellular membrane of hepatocytes, myocytes and adipocytes but also on the surface of T cells, macrophages, and dendritic cells. In murine models, the absence of IR in T-cells coincided with reduced cytokine production, proliferation, and migration. In macrophages, defective insulin signaling resulted in enhanced glycolysis affecting the responses to pathogens. In this review, we focalize on the bidirectional cause-effect relationship between impaired insulin signaling and arthritis analyzing how insulin signaling may be involved in the aberrant immune response implicated in arthritis and how inflammatory mediators affect insulin signaling. Finally, the effect of glucose-lowering agents on arthritis was summarized.

Complement component 3 as biomarker of disease activity and cardiometabolic risk factor in rheumatoid arthritis and spondyloarthritis

Objective

To analyze the relationship between complement component 3 (C3) and the prevalence of cardiometabolic risk factors and disease activity in the rheumatic diseases having the highest rates of cardiovascular morbidity and mortality: rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA).

Methods

This is a cross-sectional study including 200 RA, 80 PsA, 150 axSpA patients and 100 healthy donors. The prevalence of cardiometabolic risk factors [obesity, insulin resistance, type 2 diabetes mellitus, hyperlipidemia, apolipoprotein B/apolipoprotein A (apoB/apoA) and atherogenic risks and hypertension] was analyzed. Serum complement C3 levels, inflammatory markers and disease activity were evaluated. Cluster analysis was performed to identify different phenotypes. Receiver operating characteristic (ROC) curve analysis to assess the accuracy of complement C3 as biomarker of insulin resistance and disease activity was carried out.

Results

Levels of complement C3, significantly elevated in RA, axSpA and PsA patients, were associated with the prevalence of cardiometabolic risk factors. Hard clustering analysis identified two distinctive phenotypes of patients depending on the complement C3 levels and insulin sensitivity state. Patients from cluster 1, characterized by high levels of complement C3 displayed increased prevalence of cardiometabolic risk factors and high disease activity. ROC curve analysis showed that non-obesity related complement C3 levels allowed to identify insulin resistant patients.

Conclusions

Complement C3 is associated with the concomitant increased prevalence of cardiometabolic risk factors in rheumatoid arthritis and spondyloarthritis. Thus, complement C3 should be considered a useful marker of insulin resistance and disease activity in these rheumatic disorders.

Elevated levels of inflammatory markers in women with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune and progressive disease. Evidence indicates that inflammatory mediators may contribute to the genesis and/or evolution of this clinical condition. Thus, the objective was to evaluate and compare the plasma levels of Interleukin-17 (IL-17), Tumor Necrosis Factor-Alpha (TNF-α) and Complement 3 (C3) in women with RA and healthy controls (HC), as well as to evaluate the association them with the disease activity. 25 women with RA and 15 HC were recruited. Plasma levels of biomarkers were measured by ELISA. All statistical analyzes were performed with a significance level set at α = 0.05. In the women with RA, the median age was 55 and, in the HC, was 50 years. The median value of DAS-28 was 3.79. The plasma levels of IL-17 (p = .03), TNF-α (p ≤ 0.01) and C3 (p ≤ 0.01) were higher in women with RA. The ROC curve showed that TNF- α has a higher discriminating ability than IL-17 and C3. DAS-28 score correlated significantly with C3 levels in women with RA (r = 0.91; p < .01). These findings reaffirm the participation of the immune system in pathophysiology of RA, suggest that TNF-α levels may be a good biomarker and that elevated C3 levels contribute to the worsening of the disease.

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

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

Impact of obesity on autoimmune arthritis and its cardiovascular complications

Obesity can instigate and sustain a systemic low-grade inflammatory environment that can amplify autoimmune disorders and their associated comorbidities. Metabolic changes and inflammatory factors produced by the adipose tissue have been reported to aggravate autoimmunity and predispose the patient to cardiovascular disease (CVD) and metabolic comorbidities. Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are autoimmune arthritic diseases, often linked with altered body mass index (BMI). Severe joint inflammation and bone destruction have a debilitating impact on the patient's life; there is also a staggering risk of cardiovascular morbidity and mortality. Furthermore, these patients are at risk of developing metabolic symptoms, including insulin resistance resulting in type 2 diabetes mellitus (T2DM). In addition, arthritis severity, progression and response to therapy can be markedly affected by the patient's BMI. Hence, a complex integrative pathogenesis interconnects autoimmunity with metabolic and cardiovascular disorders. This review aims to shed light on the network that connects obesity with RA, PsA, systemic lupus erythematosus and Sjӧgren's syndrome. We have focused on clarifying the mechanism by which obesity affects different cell types, inflammatory factors and traditional therapies in these autoimmune disorders. We conclude that to further optimize arthritis therapy and to prevent CVD, it is imperative to uncover the intricate relation between obesity and arthritis pathology.

Current treatment options for psoriatic arthritis: spotlight on abatacept

Psoriatic arthritis (PsA) is a chronic inflammatory disease of joints, tendon sheaths, and entheses affecting patients with established skin psoriasis, or, less frequently, patients without a personal history of psoriasis with a positive familial history. Many treatment options are now available to deal with the different aspects of the disease, including traditional and biological disease-modifying antirheumatic drugs and the recently released targeted synthetic disease-modifying antirheumatic drugs. However, ~40% of patients still fail to achieve a meaningful clinical response to first-line biologic therapy advocating the development of novel medications. It is now well accepted that T-cells participate in the immunopathogenesis of several autoimmune diseases. For this reason, the potential intervention on T-cells represented an attractive therapeutic target for a long time, becoming a clinical reality with the development of abatacept. Abatacept is a biologic agent selectively targeting the T-cell costimulatory signal delivered through the CD80/86-CD28 pathway and was approved in December 2005 by the US Food and Drug Administration and in May 2007 by European Medicines Agency for the treatment of patients with rheumatoid arthritis in combination with methotrexate. Based on the relevant role of T-cells in PsA pathogenesis and following the positive results obtained in a phase III clinical trial, abatacept recently received approval for treatment of patients with PsA. In this review, we will focus on the current knowledge about the emerging role of abatacept in treatment of PsA.

Complement C3 and fatty liver disease in Rheumatoid arthritis patients: a cross-sectional study

BACKGROUND

Recent evidence suggested a potential role of complement fraction C3 as a biomarker of nonalcoholic fatty liver disease (NAFLD) in the general population. Aim of this study was to evaluate the performance of C3 for prediction of NAFLD in RA patients.

MATERIALS AND METHODS

For the present study, consecutive RA patients were recruited. NAFLD was diagnosed according to predefined ultrasonographic (US) criteria. For comparison, the hepatic steatosis index (HSI) was calculated.

RESULTS

Of 164 consecutive RA patients, 41 (25%) were diagnosed with NAFLD. The NAFLD group had a significant lower proportion of females (P = 0·04), higher BMI (P < 0·0001), C-reactive protein (P = 0·04), complement C3 (P = 0·001) and HSI (P = 0·003). In a logistic regression model, only male sex (OR 2·65, 95% CI: 1·08-6·50, P = 0·03), increasing BMI (OR 1·22, 95% CI: 1·02-1·46, P = 0·03) and complement C3 (OR 5·05, 95% CI: 1·06-23·93, P = 0·04) were associated with higher likelihood of being diagnosed with NAFLD. Finally, we built ROC curves for BMI, complement C3 and their combination for prediction of having NAFLD. The best cut-off for BMI was 28·5 kg/m² and yielded a sensitivity of 66% and a specificity of 71%; the best cut-off for complement C3 was 1·23 g/L and yielded a sensitivity of 76% and a specificity of 64% for classification of NAFLD cases.

CONCLUSIONS

Our results provide preliminary evidence for a potential role of complement C3 as a surrogate biomarker of NAFLD in RA patients.

Prevalence of type 2 diabetes and impaired fasting glucose in patients affected by rheumatoid arthritis: Results from a cross-sectional study

Although the better management of rheumatoid arthritis (RA) has significantly improved the long-term outcome of affected patients, a significant proportion of these may develop associated comorbidities including cardiometabolic complications. However, it must be pointed out that a comprehensive cardiometabolic evaluation is still poorly integrated into the management of RA patients, due to a limited awareness of the problem, a lack of appropriate clinical studies, and optimal strategies for cardiovascular (CV) risk reduction in RA. In addition, although several studies investigated the possible association between traditional CV risk factors and RA, conflicting results are still available.On this basis, we planned this cross-sectional study, aimed at investigating the prevalence of type 2 diabetes (T2D) and impaired fasting glucose (IFG) in RA patients compared with age- and gender- matched control individuals. Furthermore, we analyzed the role of both traditional and RA-related CV risk factors in predicting T2D and IFG.We observed an increased prevalence of T2D in RA patients when compared with age- and gender-matched controls. Regression analyses demonstrated that the presence of high blood pressure (HBP), a longer disease duration, and exposure to corticosteroids (CCS) were significantly associated with an increased likelihood of being classified as T2D. In addition, we observed an increased prevalence of IFG in RA patients when compared with age- and gender-matched controls. Regression analyses demonstrated that a higher body mass index (BMI), the presence of metabolic syndrome (MetS), higher levels of total cholesterol, the presence of radiographic damage, and higher serum levels of C-reactive protein (CRP) were significantly associated with an increased likelihood of presenting IFG.In this cross-sectional study, we observed an increased prevalence of T2D and IFG in an Italian cohort of RA patients when compared with age- and gender-matched control individuals. Interestingly, both RA-specific features, such as disease duration, CCS exposure, and radiographic damage, and traditional CV risk factors, such as HBP and MetS, were significantly associated with glucose metabolism abnormalities.

Poor clinical response in rheumatoid arthritis is the main risk factor for diabetes development in the short-term: A 1-year, single-centre, longitudinal study

OBJECTIVES

Despite of the European League Against Rheumatism (EULAR) provided different sets of recommendations for the management of cardiovascular risk in inflammatory arthritis patients, it must be pointed out that cardiometabolic comorbidity, such as type 2 diabetes (T2D), remains still underdiagnosed and undertreated in patients affected by rheumatoid arthritis (RA).

METHODS

In this work, we designed a single centre, prospective study in order to better investigate the occurrence of T2D during the course of 1 year of follow-up. Furthermore, we evaluated the role of both traditional cardiovascular and RA-specific related risk factors to predict the occurrence of new T2D.

RESULTS

In this study, we evaluated 439 consecutive RA patients and we observed that 7.1% of our patients (31/439) developed T2D, after 12 month of prospective follow-up. The regression analysis showed that the presence of high blood pressure, the impaired fasting glucose (IFG) at the first observation and the poor EULAR-DAS28 response, after 12 months of follow-up, were significantly associated with an increased likelihood of being classified as T2D. Similarly, we observed that 7.7% of our patients (34/439) showed IFG after 12 months of prospective follow-up. The regression analysis showed that the presence of high blood pressure and the poor EULAR-DAS28 response after 12 months of follow-up, were significantly associated with an increased likelihood of showing IFG.

CONCLUSIONS

Our study supports the hypothesis of a significant short-term risk of T2D in RA patients and of a close associations between uncontrolled disease activity and glucose metabolism derangement. Further multicentre, randomised-controlled studies are surely needed in order to elucidate these findings and to better ascertain the possible contribution of different therapeutic regimens to reduce this risk.

Plantar fascia enthesopathy is highly prevalent in diabetic patients without peripheral neuropathy and correlates with retinopathy and impaired kidney function

BACKGROUND

Aim of this study was to evaluate the prevalence of plantar fascia (PF) enthesopathy in Type 2 diabetes mellitus (T2DM) patients without distal peripheral neuropathy (DPN).

METHODS

We recruited 50 T2DM patients without DPN and 50 healthy controls. DPN was excluded using the Michigan Neuropathy Screening Instrument (MNSI). All patients underwent a bilateral sonographicevaluation of the enthesealportion of the PF.

RESULTS

PF thickness was significantly higher in T2DM patients (p<0.0001). T2DM patients presented a higher prevalence of entheseal thickening (p = 0.002), enthesophyte (p = 0.02) and cortical irregularity (p = 0.02). The overall sum of abnormalities was higher in T2DM patients (p<0.0001), as was the percentage of bilateral involvement (p = 0.005). In a logistic regression analysis, retinopathy predicted entheseal thickening (OR 3.5, p = 0.05) and enthesophytes (OR 5.13, p = 0.001); reduced eGFR predicted enthesophytes (OR 2.93, p = 0.04); body mass index (BMI) predicted cortical irregularity (OR 0.87, p = 0.05); mean glucose predicted enthesophyte (OR 1.01, p = 0.03); LDL cholesterol predicted cortical irregularity (OR 0.98, p = 0.02).

CONCLUSIONS

Our data suggest that T2DM is associated with PF enthesopathyindependently of DPN.