Resistin is associated with the inflammation process in patients with systemic autoimmune diseases undergoing glucocorticoid therapy: comparison with leptin and adiponectin

Role of T cells in the pathogenesis of systemic lupus erythematous: Focus on immunometabolism dysfunctions

Evidence demonstrates that T cells are implicated in developing SLE, and each of them dominantly uses distinct metabolic pathways. Indeed, intracellular enzymes and availability of specific nutrients orchestrate fate of T cells and lead to differentiation of regulatory T cells (Treg), memory T cells, helper T cells, and effector T cells. The function of T cells in inflammatory and autoimmune responses is determined by metabolic processes and activity of their enzymes. Several studies were conducted to determine metabolic abnormalities in SLE patients and clarify how these modifications could control the functions of the involved T cells. Metabolic pathways such as glycolysis, mitochondrial pathways, oxidative stress, mTOR pathway, fatty acid and amino acid metabolisms are dysregulated in SLE T cells. Moreover, immunosuppressive drugs used in treating autoimmune diseases, including SLE, could affect immunometabolism. Developing drugs to regulate autoreactive T cell metabolism could be a promising therapeutic approach for SLE treatment. Accordingly, increased knowledge about metabolic processes paves the way to understanding SLE pathogenesis better and introduces novel therapeutic options for SLE treatment. Although monotherapy with metabolic pathways modulators might not be sufficient to prevent autoimmune disease, they may be an ideal adjuvant to reduce administration doses of immunosuppressive drugs, thus reducing drug-associated adverse effects. This review summarized emerging data about T cells that are involved in SLE pathogenesis, focusing on immunometabolism dysregulation and how these modifications could affect the disease development.

Association of obesity with arterial stiffness: The Multi-Ethnic Study of Atherosclerosis (MESA)

Arterial stiffness (AS) and obesity are recognized as important risk factors of cardiovascular disease (CVD). The purpose of this study was to investigate the relationship between AS and obesity. AS was defined as high augmentation index (AIx) and low elasticity (C1, large artery elasticity; C2, small artery elasticity) in participants enrolled in the Multi-Ethnic Study of Atherosclerosis at baseline. We compared AIx, C1, and C2 by body mass index (BMI) (< 25, 25-29.9, 30-39.9, ⩾ 40 kg/m²) and waist-hip ratio (WHR) (< 0.85, 0.85-0.99, ⩾ 1). The obesity-AS association was tested across 10-year age intervals. Among 6177 participants (62 ± 10 years old, 52% female), a significant inverse relationship was observed between obesity and AS. After adjustments for CVD risk factors, participants with a BMI > 40 kg/m² had 5.4% lower AIx (mean difference [Δ] = -0.82%; 95% CI: -1.10, -0.53), 15.4% higher C1 (Δ = 1.66 mL/mmHg ×10; 95% CI: 1.00, 2.33), and 40.2% higher C2 (Δ = 1.49 mL/mmHg ×100; 95% CI: 1.15, 1.83) compared to those with a BMI < 25 kg/m² (all p for trend < 0.001). Participants with a WHR ⩾ 1 had 5.6% higher C1 (∆ = 0.92 mL/mmHg ×10; 95% CI: 0.47, 1.37) compared to those with a WHR < 0.85. The WHR had a significant interaction with age on AIx and C2, but not with BMI; the inverse relationships of the WHR with AIx and C2 were observed only in participants < 55 years between the normal (WHR < 0.85) and the overweight (0.85 ⩽ WHR < 0.99) groups. Different associations of WHR and BMI with arterial stiffness among older adults should be further investigated.

Association between circulating leptin levels and systemic lupus erythematosus: an updated meta-analysis

Objective We aimed to evaluate the relationship between circulating leptin levels and systemic lupus erythematosus (SLE). Methods MEDLINE, EMBASE, and Cochrane library databases were searched. Meta-analyses were performed comparing serum/plasma leptin levels in patients with SLE and healthy controls, and on patients with SLE in subgroups based on ethnicity, sample size, data type, and matched variables (age, sex, and/or body mass index (BMI)). Results Eighteen studies including 1333 patients with SLE and 1048 controls were ultimately selected, which showed that leptin levels were significantly higher in the SLE group than in the control group (SMD = 0.611, 95% CI = 0.275-0.947, p < 0.001). When we excluded two outlier studies because of high heterogeneity, leptin levels were also significantly higher in the SLE group than in the control group (SMD = 0.619, 95% CI = 0.431-0.807, p < 0.001). Stratification by ethnicity showed significantly elevated leptin levels in the SLE group in European, Asian, Arab, Latin American, and mixed populations. Subgroup analysis by sample size showed significantly higher leptin levels in the SLE group by small ( n ≤ 100) and large sample numbers ( n > 100) (SMD = 0.780, 95% CI = 0.445-1.115, p < 0.001; SMD = 0.495, 95% CI = 0.275-0.715, p < 0.001). Stratification by data type revealed significantly higher leptin levels in the original data and imputed data groups. Subgroup analysis adjustment revealed significantly higher leptin levels in the SLE group, regardless of adjustment for variables. Conclusions Our meta-analysis demonstrated that leptin levels were significantly higher in patients with SLE, regardless of ethnicity, sample size, data type, and matched variables.

Immunometabolism in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease mediated by pathogenic autoantibodies directed against nucleoprotein complexes. Beyond the activation of autoreactive B cells, this process involves dysregulation in many other types of immune cells, including CD4⁺ T cells, dendritic cells, macrophages and neutrophils. Metabolic substrate utilization and integration of cues from energy sensors are critical checkpoints of effector functions in the immune system, with common as well as cell-specific programmes. Patients with SLE and lupus-prone mice present with activated metabolism of CD4⁺ T cells, and the use of metabolic inhibitors to normalize these features is associated with therapeutic effects. Far less is known about the metabolic requirements of B cells and myeloid cells in SLE. This article reviews current knowledge of the alterations in metabolism of immune cells in patients with SLE and mouse models of lupus in the context of what is known about the metabolic regulation of these cells during normal immune responses. How these alterations might contribute to lupus pathogenesis and how they can be targeted therapeutically are also discussed.

Serum Resistin Level and Progression of Atherosclerosis during Glucocorticoid Therapy for Systemic Autoimmune Diseases

Adipokines are important regulators of several processes, including inflammation and atherosclerosis. In patients with systemic autoimmune diseases, atherosclerosis is accelerated with higher cardiovascular morbidity and mortality. We prospectively investigated the association of adipokines and glucocorticoid therapy with progression of premature atherosclerosis in 38 patients starting glucocorticoid therapy for systemic autoimmune diseases. To detect premature atherosclerosis, carotid ultrasonography was performed at initiation of glucocorticoid therapy and after a mean three-year follow-up period. The ankle-brachial pressure index and cardio-ankle vascular index (CAVI) were measured. Serum adipokine levels were determined with enzyme-linked immunosorbent assay kits. Twenty-three patients (60.5%) had carotid artery plaque at baseline. The carotid artery intima-media thickness (IMT) increased significantly during follow-up. Glucocorticoids reduced the serum resistin level, while increasing serum leptin and high molecular weight-adiponectin. There was slower progression of atherosclerosis (carotid IMT and CAVI) at follow-up in patients with greater reduction of serum resistin and with higher cumulative prednisolone dose. In conclusion, progression of premature atherosclerosis occurred at an early stage of systemic autoimmune diseases before initiation of glucocorticoid therapy. Since resistin, an inflammation and atherosclerosis related adipokine, is reduced by glucocorticoids, glucocortidoid therapy may not accelerate atherosclerosis in patients with systemic autoimmune diseases.

Identification of Pathway-Specific Serum Biomarkers of Response to Glucocorticoid and Infliximab Treatment in Children with Inflammatory Bowel Disease

OBJECTIVE

Serum biomarkers may serve to predict early response to therapy, identify relapse, and facilitate drug development in inflammatory bowel disease (IBD). Biomarkers are particularly important in children, in whom achieving early remission and minimizing procedures are especially beneficial.

METHODS

We profiled protein and micro RNA (miRNA) in serum from patients pre- and post-therapy, to identify molecular markers of pharmacodynamic effect. Serum was obtained from children with IBD before and after treatment with either corticosteroids (prednisone; n=12) or anti-tumor necrosis factor-α biologic (infliximab; n=7). Over 1,100 serum proteins were assayed using aptamer-based SOMAscan proteomics, and 22 miRNAs analyzed by quantitative real time PCR. Concordance of longitudinal changes between the groups was used to identify markers responsive to treatment. Bioinformatic analysis was used to build insight into mechanisms of changes in response to treatment.

RESULTS

We identified 18 proteins and three miRNAs responsive to both prednisone and infliximab. Eight markers that decreased are associated with inflammation and have gene promoters regulated by nuclear factor (NF)-κB. Several that increased are associated with resolving inflammation and tissue damage. We also identified six markers that appear to be steroid-specific, three of which have glucocorticoid receptor binding elements in their promoter region.

CONCLUSIONS

Serum markers regulated by the inflammatory transcription factor NF-κB are potential candidates for pharmacodynamic biomarkers that, if correlated with later outcomes like endoscopic or histologic healing, could be used to monitor treatment, optimize dosing, and enhance drug development. The pharmacodynamic biomarkers identified here hold potential to improve both clinical care and drug development. Further studies are warranted to investigate these markers as early predictors of response, or possibly surrogate outcomes.

Clinical potential of resistin as a novel prognostic biomarker for cellulitis

Cellulitis is an acute, subacute or chronic inflammation of the dermis and subdermal tissues, which is typically caused by bacteria, although other causes are possible. The present study aimed to evaluate the association between resistin levels and the recovery time of patients with cellulitis. In addition, the effect of resistin and insulin resistance on the prognosis of cellulitis was investigated. In total, 52 patients with cellulitis (male, 21; female, 31) and an age-matched group of 42 healthy individuals (male, 18; female, 24) were included in the study. The levels of serum resistin, fasting plasma glucose (FPG), homeostasis model assessment-insulin resistance (HOMA-IR), C-reactive protein (CRP) and other biochemical parameters were compared between the groups. The mean resistin levels in the cellulitis and control groups were 9.4±5.3 and 5.8±3.1 ng/ml, respectively. The levels of resistin, FPG, HOMA-IR and CRP were significantly higher in the cellulitis group compared with the control group (P<0.001). Furthermore, the mean recovery time of the patients with cellulitis was 21.2±5.6 days. Thus, increased levels of resistin (P=0.002) and HOMA-IR (P=0.005) could be used as predictive factors for the recovery time. The enhanced levels of resistin and HOMA-IR were shown to correlate with the high CRP levels in the cellulitis group. Therefore, the results indicated that increased levels of resistin may function as a prognostic marker for cellulitis.

Adipokine gene expression in peripheral blood of adult and juvenile dermatomyositis patients and their relation to clinical parameters and disease activity measures

Objective

Recently adipokines have been implicated in the regulation of immune and inflammatory responses in autoimmune disease. To investigate the role of adipokines in adult and pediatric patients with newly diagnosed dermatomyositis (DM), we analyzed peripheral blood and skeletal muscle gene expression of four adipokines: visfatin, leptin, adiponectin and resistin.

Methods

Peripheral blood mononuclear cells (PBMCs) were collected for 21 adult DM, 26 juvenile DM, 5 non-disease adult controls, and 6 non-disease pediatric controls at two time points: baseline and 6 months. Muscle biopsies from 5 adult DM patients and 5 non-disease adult controls were collected at baseline. Similarly, muscle biopsies from 7 juvenile DM patients and 5 non-disease pediatric controls were collected at baseline. The gene expression levels of leptin, adiponectin, resistin, visfatin and related inflammatory cytokines, IL-6, TNF- α, and housekeeping genes GAPDH, B2M, and ACTB were generated using a custom RT² Profiler PCR Array.

Results

Visfatin gene expression levels in peripheral blood were significantly higher in newly diagnosed adult DM cases compared to non-disease controls (P = 0.004) and these levels correlated with baseline clinical parameters such as age (r = 0.34, P = 0.020), male sex (r = −0.35, P = 0.017), prednisone use (r = −0.42, P = 0.006), and DMARD use (r = 0.35, P = 0.025). No significant association was found between change in visfatin gene expression levels and change in disease activity measures. While visfatin gene expression was significantly up-regulated in muscle tissue of juvenile DM patients (P = 0.028), in adult DM patients only a trend towards significance was observed (P = 0.08). Also, muscle gene expression levels of resistin were significantly elevated in both adult and juvenile DM patients compared respectively to non-disease adult and pediatric controls. Furthermore, an association between peripheral blood resistin gene expression and DM disease activity, including global, muscle, and extra-skeletal disease activity was also observed.

Conclusion

Peripheral blood visfatin gene expression and muscle resistin gene expression are significantly increased in newly diagnosed adult DM patients. Further longitudinal studies should explore the possibility of using gene expression levels of adipokines such as visfatin and resistin as novel clinical diagnostic biomarkers in DM.