Resistin, an adipokine with potent proinflammatory properties

Resistin in idiopathic inflammatory myopathies

INTRODUCTION

The purpose of this study was to evaluate and compare the serum levels and local expression of resistin in patients with idiopathic inflammatory myopathies to controls, and to determine the relationship between resistin levels, inflammation and disease activity.

METHODS

Serum resistin levels were determined in 42 patients with inflammatory myopathies and 27 healthy controls. The association among resistin levels, inflammation, global disease activity and muscle strength was examined. The expression of resistin in muscle tissues from patients with inflammatory myopathies and healthy controls was evaluated. Gene expression and protein release from resistin-stimulated muscle and mononuclear cells were assessed.

RESULTS

In patients with inflammatory myopathies, the serum levels of resistin were significantly higher than those observed in controls (8.53 ± 6.84 vs. 4.54 ± 1.08 ng/ml, P < 0.0001) and correlated with C-reactive protein (CRP) levels (r = 0.328, P = 0.044) and myositis disease activity assessment visual analogue scales (MYOACT) (r = 0.382, P = 0.026). Stronger association was observed between the levels of serum resistin and CRP levels (r = 0.717, P = 0.037) as well as MYOACT (r = 0.798, P = 0.007), and there was a trend towards correlation between serum resistin and myoglobin levels (r = 0.650, P = 0.067) in anti-Jo-1 positive patients. Furthermore, in patients with dermatomyositis, serum resistin levels significantly correlated with MYOACT (r = 0.667, P = 0.001), creatine kinase (r = 0.739, P = 0.001) and myoglobin levels (r = 0.791, P = 0.0003) and showed a trend towards correlation with CRP levels (r = 0.447, P = 0.067). Resistin expression in muscle tissue was significantly higher in patients with inflammatory myopathies compared to controls, and resistin induced the expression of interleukins (IL)-1β and IL-6 and monocyte chemoattractant protein (MCP)-1 in mononuclear cells but not in myocytes.

CONCLUSIONS

The results of this study indicate that higher levels of serum resistin are associated with inflammation, higher global disease activity index and muscle injury in patients with myositis-specific anti-Jo-1 antibody and patients with dermatomyositis. Furthermore, up-regulation of resistin in muscle tissue and resistin-induced synthesis of pro-inflammatory cytokines in mononuclear cells suggest a potential role for resistin in the pathogenesis of inflammatory myopathies.

The serum profile of adipokines in naïve patients with diabetes mellitus type 2 and obesity

BACKGROUND

The aim of this study was to explore the relationship of serum profile of adipokines with cardiovascular risk factors and anthropometric parameters in patients with diabetes mellitus type 2.

SUBJECTS

A population of 108 obese patients with DM2 was analyzed. A complete biochemical anthropometric and nutritional evaluation was performed.

RESULTS

In the analysis with leptin as a dependent variable, the IL-6 and glucose levels remained in the model (F = 6.2; P<0.05), with an increase of 5.8 (CI 95%:2.7-7.6) ng/ml with each 1 pg/ml of IL-6 and of 5.2 (CI95%:2.5-5.8) ng/ml with each 1 mg/dl of glucose. In a second model with adiponectin as a dependent variable, the BMI remained in the model (F = 3.77;P<0.05), with an decrease of -3.77 (CI 95%:0.53-7.1) ng/ml with each 1 point of BMI. In the third multivariate analysis with IL-6 as a dependent variable, the glucose level remained in the model (F = 10.1; P<0.01), with an increase of 0.09 (CI95%:0.06-0.12) pg/ml with each 1 mg/dl of glucose. In the fourth multivariate analysis with resistin as a dependent variable, the CRP remained in the model (F = 2.51; P<0.05), with an increase of 0.28 (CI 95%:0.08-0.48) pg/ml with each 1 mg/dl of CRP.

CONCLUSION

Serum profile of adipokines is associated with different risk factors in diabetic obese patients.

High-fat diet feeding induces a depot-dependent response on the pro-inflammatory state and mitochondrial function of gonadal white adipose tissue

Obesity has been related to a chronic pro-inflammatory state affecting white adipose tissue (WAT), which has a great impact on carbohydrate, lipid and energy metabolism. In turn, the dysregulation of adipokine secretion derived from the accumulation of excess lipids in adipocytes further contributes to the development of insulin resistance and can be associated with mitochondrial dysfunction. The aim of the present study was to determine whether sexual dimorphism found in the systemic insulin sensitivity profile is related to sex differences in a high-fat diet (HFD) response of gonadal WAT at mitochondrial function and inflammatory profile levels. Wistar rats (10 weeks old) of both sexes were fed a control pelleted diet (3 % (w/w) fat;n8 for each sex) or a HFD (24 % (w/w) fat;n8 for each sex). Serum insulin sensitivity markers, mRNA expression levels of inflammatory factors and the protein content of insulin and adiponectin signalling pathways were analysed, as well as the levels of the main markers of mitochondrial biogenesis, antioxidant defence and oxidative damage. In the present study, the periovarian depot exhibits a greater expandability capacity, along with a lower hypoxic and pro-inflammatory state, without signs of mitochondrial dysfunction or changes in its dynamics. In contrast, epididymal fat has a much more pronounced pro-inflammatory, hypoxic and insulin-resistant profile accompanied by changes in mitochondrial dynamics, probably associated with HFD-induced mitochondrial dysfunction. Thus, this explains the worse serum insulin sensitivity profile of male rats.

Retroperitoneal white adipose tissue mitochondrial function and adiponectin expression in response to ovariectomy and 17β-estradiol replacement

Sexual dimorphism has been previously found both in mitochondrial biogenesis and function and in adiponectin expression of retroperitoneal WAT. However, little is known about the E2 effects on WAT mitochondrial function. Accordingly, the aim of this study was to examine in greater depth the role of estrogens in sexual dimorphism. This was accomplished by studying the effects of ovariectomy and E2 replacement on retroperitoneal WAT mitochondrial function. Fourteen-week-old female and ovariectomized (OVX) female Wistar rats were used in this study. The ovariectomy was performed at 5 weeks of age and at 10 weeks of age OVX rats were divided into two experimental groups: OVX, and OVX treated with 17β-estradiol (E2) (OVX+E2). Subcutaneous injections of E2 (10 μg/kg/48 h) were administered to the OVX+E2 rats for 4 weeks previous to the sacrifice whereas OVX rats were treated only with the vehicle. Levels of the main markers for mitochondrial biogenesis and function and those representatives of the antioxidant defense system and insulin sensitivity were determined. Additionally, the mRNA levels of the α and β estrogen receptors and of some adipocyte differentiation markers were studied. Our results indicate that retroperitoneal WAT was able to adapt itself to ovariectomy without any changes in mitochondrial function markers or for the adiponectin levels. However, E2 supplementation led to an unexpected decrease in: TFAM protein levels, in LPL, PPARγ and adiponectin gene expression and in the systemic HMW adiponectin levels. This decrease is probably due to the down-regulation of the ERα mRNA expression to avoid an over-stimulation by E2.

Inflammation and oxidative stress in obesity-related glomerulopathy

Obesity-related glomerulopathy is an increasing cause of end-stage renal disease. Obesity has been considered a state of chronic low-grade systemic inflammation and chronic oxidative stress. Augmented inflammation in adipose and kidney tissues promotes the progression of kidney damage in obesity. Adipose tissue, which is accumulated in obesity, is a key endocrine organ that produces multiple biologically active molecules, including leptin, adiponectin, resistin, that affect inflammation, and subsequent deregulation of cell function in renal glomeruli that leads to pathological changes. Oxidative stress is also associated with obesity-related renal diseases and may trigger the initiation or progression of renal damage in obesity. In this paper, we focus on inflammation and oxidative stress in the progression of obesity-related glomerulopathy and possible interventions to prevent kidney injury in obesity.

Inflammation and metabolic dysfunction: links to cardiovascular diseases

Abdominal obesity is a major risk factor for cardiovascular disease, and recent studies highlight a key role of adipose tissue dysfunction, inflammation, and aberrant adipokine release in this process. An increased demand for lipid storage results in both hyperplasia and hypertrophy, finally leading to chronic inflammation, hypoxia, and a phenotypic change of the cellular components of adipose tissue, collectively leading to a substantially altered secretory output of adipose tissue. In this review we have assessed the adipo-vascular axis, and an overview of adipokines associated with cardiovascular disease is provided. This resulted in a first list of more than 30 adipokines. A deeper analysis only considered adipokines that have been reported to impact on inflammation and NF-κB activation in the vasculature. Out of these, the most prominent link to cardiovascular disease was found for leptin, TNF-α, adipocyte fatty acid-binding protein, interleukins, and several novel adipokines such as lipocalin-2 and pigment epithelium-derived factor. Future work will need to address the potential role of these molecules as biomarkers and/or drug targets.

Aromatase inhibitors, estrogens and musculoskeletal pain: estrogen-dependent T-cell leukemia 1A (TCL1A) gene-mediated regulation of cytokine expression

Introduction

Arthralgias and myalgias are major side effects associated with aromatase inhibitor (AI) therapy of breast cancer. In a recent genome-wide association study, we identified SNPs - including one that created an estrogen response element near the 3' end of the T-cell leukemia 1A (TCL1A) gene - that were associated with musculoskeletal pain in women on adjuvant AI therapy for breast cancer. We also showed estrogen-dependent, SNP-modulated variation in TCL1A expression and, in preliminary experiments, showed that TCL1A could induce IL-17RA expression. In the present study, we set out to determine whether these SNPs might influence cytokine expression and effect more widely, and, if so, to explore the mechanism of TCL1A-related AI-induced side effects.

Methods

The functional genomic experiments performed included determinations of TCL1A, cytokine and cytokine receptor expression in response to estrogen treatment of U2OS cells and lymphoblastoid cell lines that had been stably transfected with estrogen receptor alpha. Changes in mRNA and protein expression after gene knockdown and overexpression were also determined, as was NF-κB transcriptional activity.

Results

Estradiol (E2) increased TCL1A expression and, in a TCL1A SNP-dependent fashion, also altered the expression of IL-17, IL-17RA, IL-12, IL-12RB2 and IL-1R2. TCL1A expression was higher in E2-treated lymphoblastoid cell lines with variant SNP genotypes, and induction of the expression of cytokine and cytokine receptor genes was mediated by TCL1A. Finally, estrogen receptor alpha blockade with ICI-182,780 in the presence of E2 resulted in greatly increased NF-κB transcriptional activity, but only in cells that carried variant SNP genotypes. These results linked variant TCL1A SNP sequences that are associated with AI-dependent musculoskeletal pain with increased E2-dependent TCL1A expression and with downstream alterations in cytokine and cytokine receptor expression as well as NF-κB transcriptional activity.

Conclusions

SNPs near the 3' terminus of TCL1A were associated with AI-dependent musculoskeletal pain. E2 induced SNP-dependent TCL1A expression, which in turn altered IL-17, IL-17RA, IL-12, IL-12RB2, and IL-1R2 expression as well as NF-κB transcriptional activity. These results provide a pharmacogenomic explanation for a clinically important adverse drug reaction as well as insights into a novel estrogen-dependent mechanism for the modulation of cytokine and cytokine receptor expression.

[Serum and synovial adiponectin, resistin, and visfatin levels in rheumatoid arthritis patients. Relation to disease activity]

BACKGROUND

Recent data provided evidence on the implication of the adipocytokines adiponectin, visfatin, and resistin in inflammation, immune response, and tissue destruction and revealed several links between them and arthritis.

AIM OF THE STUDY

The purpose of this study was to assess the levels of adiponectin, visfatin, and resistin in serum and synovial fluid of patients with rheumatoid arthritis (RA) and their relationship with disease activity.

SUBJECTS AND METHODS

A total of 70 female patients with RA and 30 age- and sex-matched healthy controls were enrolled. The clinical activity of RA patients was assessed according to the 28 joint count Disease Activity Score and patients were classified into two groups: 39 patients with active disease (group A) and 31 patients in remission (group B). Synovial fluid was obtained by arthrocentesis of the affected knee joints from 39 patients with active disease. Serum adiponectin, visfatin, and resistin concentrations were measured in RA patients and controls, while a specific enzyme-linked immunosorbent assay was used to measure the synovial concentrations of adiponectin, visfatin, and resistin in the group of patients with active RA.

RESULTS

Serum levels of adiponectin and visfatin were significantly higher in all RA patients and patients with active disease compared to the control group and patients in remission. No significant difference was observed in the resistin level between patients and controls. Serum and synovial adiponectin and visfatin were positively correlated with DAS28-ESR in RA patients with active disease.

CONCLUSION

Our data demonstrated that adiponectin and visfatin are related to disease activity in RA patients and might be involved in the progression of RA. The English full-text version of this article is available at SpringerLink (under "Supplemental").

TP-58, a novel thienopyridine derivative, protects mice from concanavalinA-induced hepatitis by suppressing inflammation

Hepatitis represents a ubiquitous human health problem but effective therapies with limited side effects are still lacking. In this study, we investigated the effect and mechanism of TP-58, a novel thienopyridine derivative, on a murine fulminant hepatitis model induced by concanavalin A (ConA). We found TP-58 markedly alleviated ConA-caused liver injury and increased survival ratio of mice injected with a lethal dose of ConA. Oral administration of TP-58 significantly alleviated ConA-caused liver injury in mice by the reduction of serum aminotransferases and liver necrosis.The analysis of proinflammatory cytokines showed that TP-58 decreased both hepatic mRNA expressions and serum protein levels of TNF-α and IL-6. And the result from LPS-stimulated RAW 264.7 cells showed TP-58 suppressed the production of TNF-α, IL-6, and Nitro Oxide (NO) in the supernatant of LPS-stimulated RAW 264.7 cells. The study of activation of nuclear factor-κB (NF-κB) by electrophoretic mobility shift assay (EMSA) showed that TP-58 inhibited the activation of NF-κB both in vivo and in vitro. The inhibitory effect was also accompanied by a parallel reduction of IκB phosphorylation. These results indicate that TP-58 protects against liver injury by inhibition of the NF-κB-mediated inflammation and suggest a potential role of TP-58 against acute liver injury and other inflammatory diseases.

Resistin expression in breast cancer tissue as a marker of prognosis and hormone therapy stratification

OBJECTIVE

Adipocytokines are adipocyte-derived hormones and well documented to be involved in carcinogenesis. The expression of resistin, a newly discovered adipocytokine, in breast cancer tissues was determined and correlated with patient clinicopathological variables.

METHODS

Resistin expression in breast cancer tissues and the normal adjacent breast tissues was analyzed by immunohistochemistry and was correlated with clinicopathological variables as well as recurrence rates by the chi-square test. The prognostic value of resistin for disease-free and overall survival was determined by Kaplan-Meier estimates, and the significance of differences between curves was evaluated by the log-rank test.

RESULTS

High resistin expression was predominantly observed in breast cancer tissues but not the adjacent normal breast tissues. High resistin expression in breast cancer tissues was correlated significantly with tumor stage, tumor size, lymph node metastasis and estrogen receptor status. Hormone therapy, but not radiotherapy or chemotherapy, decreased the recurrence rate in patients with high resistin expression. While high resistin expression was associated with poor disease-free and overall survival, Cox regression analysis also revealed that resistin was an independent predictor of disease-free and overall survival.

CONCLUSIONS

High resistin expression in breast cancer tissue is associated with a more malignant clinicopathological status as well as poor patient survival. Resistin may therefore hold promise as an independent prognosis predictor for breast cancer, as a marker for hormone therapy stratification and as a potential therapeutic target.

High prevalence of autoantibodies to C-reactive protein in patients with chronic hepatitis C infection: association with liver fibrosis and portal inflammation

The presence of autoantibodies against C-reactive protein (anti-CRP) has been reported in association with autoimmunity and histopathology in chronic hepatitis C virus (HCV) infection. Resistin could play a role in the pathogenesis of hepatitis, although results on HCV infection are ambiguous. Here we retrospectively analyzed anti-CRP and resistin levels in the sera of 38 untreated and well-characterized HCV patients at the time of their first liver biopsy. HCV activity and general health were assessed by a physician at least yearly until follow-up ended. Anti-CRP and resistin were also measured in patients with autoimmune hepatitis (AIH) and nonalcoholic fatty liver disease (NAFLD). Anti-CRP antibodies were registered in all HCV patients, whereas only a few AIH (11%) and NAFLD (12%) sera were positive. Anti-CRP levels were related to histopathological severity and were highest in patients with cirrhosis at baseline. Resistin levels were similar in HCV, AIH, and NAFLD patients, but high levels of resistin were associated with early mortality in HCV patients. Neither anti-CRP nor resistin predicted a response to interferon-based therapy or cirrhosis development or was associated with liver-related mortality. We conclude that anti-CRP antibodies are frequently observed in chronic HCV infection and could be a useful marker of advanced fibrosis and portal inflammation.

Circulating levels of resistin, IL-6 and lipid profile in elderly patients with ischemic heart disease with and without diabetes

Background: The cytokines that act as inflammatory hormones show a role in coronary atherosclerotic disease. Aims: This study aimed to measure serum resistin, IL-6 levels and lipid profile in nondiabetic controls, diabetics, and ischemic heart disease subjects with and without diabetes. Association between resistin and IL-6 was also determined. Materials & methods: In this comparative cross-sectional study, 147 subjects were selected, aged between 40 and 70 years. Subjects were divided into four groups as mentioned above. Plasma glucose was measured using the gluco-oxidase method. Lipid profile levels were measured using standard enzymatic methods. Levels of resistin and IL-6 were determined by ELISA. Results: Out of 147 patients, 36 were controls and 111 were cases. Serum resistin and IL-6 levels increased significantly in diabetics (23.4 ± 0.74 ng/ml and 73.1 ± 2.57 ng/ml, respectively) and nondiabetics with ischemic heart disease (14.1 ± 0.51 ng/ml and 66.2 ± 2.08 ng/ml, respectively) compared with diabetics and nondiabetic controls. Positive correlations were found between IL-6 and resistin, and a significant positive correlation was shown in ischemic heart disease groups (r = 0.659; p = 0.001). Conclusion: This study shows that the plasma resistin and IL-6 concentrations increased significantly in patients with ischemic heart disease with and without diabetes. This shows that there is a possible role of resistin and IL-6 in inflammatory processes, especially in atherosclerosis.

Measurement of salivary resistin level in patients with type 2 diabetes

Serum resistin was initially hypothesized as a link between obesity and insulin resistance in mice. The latest evidence suggests that serum resistin is proinflammatory cytokines. Inflammation plays a key role in the pathogenesis of type 2 diabetes mellitus (T2DM). Many reports have previously identified changed serum resistin levels in patients with T2DM, but little is known of the levels of resistin in saliva. In our study, saliva and serum samples were collected from 38 patients with newly diagnosed T2DM at each time point of OGTT and 35 nondiabetic controls at fasting state. Resistin concentrations were measured using ELISA. We have demonstrated the presence of resistin in saliva of T2DM and nondiabetic subjects. Saliva resistin levels of T2DM are significantly higher than those of nondiabetic controls. Resistin levels in saliva are not affected by eating activity and correlated with serum resistin levels at any time points of OGTT. A positive correlation of serum and salivary resistin with BMI and HOMA-IR existed in T2DM. Measurement of resistin in saliva is a simple, noninvasive and may be an acceptable alternative to blood sampling for evaluatinginflammation/obesity/insulin resistance state.

Adipokine actions on cartilage homeostasis

Epidemiological studies have shown an intriguing correlation between obesity and articular cartilage disease. An increase in mechanical forces across weight-bearing joints has long been considered the primary factor leading to joint degeneration. However, emerging data suggest that additional soluble factors such as the adipocyte-derived molecules "adipokines" may also play an important role in the onset and progression of weight-associated cartilage degradative process. Adipokines are pleiotropic secretory molecules mainly produced by white adipose tissue. Adipokines exert their actions through endocrine, paracrine, autocrine, or juxtacrine cross talk in a wide variety of physiological or pathophysiological processes. In particular, they are mainly involved in the regulation of food intake and energy metabolism, in both health and disease states, and in the inflammatory response. Recent observations have shown that, among adipokines, leptin, adiponectin, resistin, visfatin, and apelin may also participate to the complex mechanisms that regulate skeleton biology, both at bone and cartilage level. Herein, we review the present knowledge about the role of these adipokines in cartilage function as well as in inflammatory and degenerative joint diseases. Moreover, we describe some methodological approaches which can be utilized in the measurement of these adipokines in different biological matrices, like plasma and synovial fluid (SF), and may be helpful to better clarify the involvement of these molecules in cartilage disease.

Serum adiponectin and resistin in relation to insulin resistance and markers of hyperandrogenism in lean and obese women with polycystic ovary syndrome

OBJECTIVE

The role of insulin resistance in polycystic ovary syndrome (PCOS) has been established. However the role of adiponectin and resistin in the relationship between insulin resistance as markers of obesity and PCOS has not been conclusive. This study aims to determine the influence of the serum levels of adiponectin and resistin on PCOS, and assess possible correlations with the hormonal and metabolic parameters of the syndrome and obesity.

METHODS

This study continued a case control study that had finished recruiting 24 subjects of reproductive women with PCOS as a case group, and 24 subjects of normal ovulatory reproductive women without hyperandrogenism as a control group. Further, only 18 subjects of the control group had a body mass index (BMI) <25 kg/m(2) and were included the data analysis, whereas others were excluded. Therefore, these study data were divided into three groups. Twenty-four PCOS patients from the case group were allocated to two groups, A (n = 14) patients had PCOS + BMI ≥25 kg/m(2); B (n = 10) patients had PCOS + BMI <25 kg/m(2). Group C was the control group of 18 reproductive women without PCOS + BMI <25 kg/m(2). Blood samples were collected between day 3 and 5 of a spontaneous menstrual cycle, at 07:00 to 09:00, after overnight fasting. Serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), total testosterone, prolactin, sex hormone-binding globulin (SHBG), glucose, insulin, adiponectin and resistin were measured.

RESULTS

Serum adiponectin levels were significantly decreased in group A compared with group B and group C. No significant difference existed in adiponectin between group B and group C. Homeostasis Model of Assessment-Insulin Resistance (HOMA-IR) value in group A was found to be significantly higher than group C, but no significant differences were found between group B and group C or between group A and group B. There was no significant difference in serum resistin between all groups, nevertheless the resistin-to-adiponectin (R:A) ratio was significantly decreased in group A compared with groups B and C. In a multiple regression model, BMI, testosterone and insulin resistance were the major determinants of hypoadiponectinemia. However, only BMI was the major determinant of the resistin represented by the R:A ratio.

CONCLUSIONS

Serum adiponectin levels and the ratio of resistin to adiponectin levels are reduced in obese women with PCOS. These results suggest that, by reducing adiponectin serum level, hyperandrogenemia, together with nutritional status of obesity, might contribute to insulin resistance in the pathogenesis of PCOS.

Resistin is associated with breach of tolerance and anti-nuclear antibodies in patients with hepatobiliary inflammation

Resistin is a cysteine-rich protein, which is abundantly expressed at the site of inflammation, and acts as a regulator of the NF-kB-dependent cytokine cascade. The aim of this study was to evaluate resistin levels in relation to inflammatory mediators, disease phenotype and autoantibody status in a spectrum of pathological conditions of the gastrointestinal tract. Resistin levels were measured with an ELISA in sera originated from 227 patients and 40 healthy controls (HC). Fifty patients diagnosed with non-alcoholic fatty liver disease (NAFLD), 53 ulcerative colitis (UC), 51 Crohn's disease (CD), 46 autoimmune hepatitis (AIH) and 27 primary sclerosing cholangitis (PSC) were included. The sera were analysed with respect to biochemical parameters of systemic inflammation and liver function and to the presence of antibodies to nuclear antigens (ANA), mitochondria (AMA) and smooth muscle (SMA). Compared with HC, resistin levels were raised in AIH (P = 0.017) and PSC (P = 0.03); compared with NAFLD, levels were elevated in CD (P = 0.041), AIH (P < 0.001) and PSC (P < 0.001). Patients with elevated levels of resistin were more often treated with corticosteroids, but no difference was found between active disease and clinical remission. Resistin levels were significantly higher in ANA-positive individuals compared with ANA-negative (P = 0.025). Resistin levels were directly correlated with IL-6 (r = 0.30, P = 0.02) and IL-8 (r = 0.51, P < 0.001). Elevated levels of resistin were prominent in patients with hepatobiliary inflammation and were associated with breach of self-tolerance, i.e. ANA positivity. Thus, we propose that resistin may be an important marker of disease severity in autoantibody-mediated gastrointestinal inflammatory diseases.

Baseline serum adipokine levels predict radiographic progression in early rheumatoid arthritis

OBJECTIVE

Adipose tissue can secrete soluble mediators (adipokines) with potent immune regulatory functions. Some adipokines have been previously associated with radiographic damage in patients with rheumatoid arthritis (RA). In the present study, we investigated the capacity of baseline adipokine levels to predict radiographic progression over a period of 4 years and studied their contribution relative to that of other known risk factors, such as anti-cyclic citrullinated peptide (anti-CCP) antibodies.

METHODS

Serum concentrations of leptin, visfatin, resistin, adiponectin, adipsin, tumor necrosis factor α (TNFα), and interleukin-6 (IL-6) were determined in serum samples obtained at baseline from 253 patients with RA from the Early Arthritis Cohort. The association between levels of these adipokines and radiographic progression was determined using a multivariate normal regression model correcting for age, sex, treatment strategy, body mass index (BMI), and the presence of anti-CCP antibodies.

RESULTS

Levels of IL-6, TNFα, visfatin, and adiponectin were positively associated with radiographic progression over 4 years. This association was independent of BMI. However, only adiponectin levels remained significantly associated with radiographic progression when the model was corrected for the presence of anti-CCP antibodies, whereas a trend was observed for IL-6. The association of both TNFα and visfatin with radiographic damage disappeared after correction for the presence of anti-CCP antibodies, which is consistent with the fact that the levels of both cytokines correlated significantly with anti-CCP antibody levels in these patients.

CONCLUSION

Our results indicate that adipokines are predictors of radiographic progression in RA, possibly through distinct underlying biologic mechanisms.

Adipokines: biofactors from white adipose tissue. A complex hub among inflammation, metabolism, and immunity

Until the identification of leptin, the first adipokine discovered in 1994, adipose tissue was considered only as an energy storage tissue. However, it is now clear that adipose tissue is an endocrine/paracrine/autocrine organ, which plays a relevant role in physiopathology of several inflammatory diseases. Actually, it is mainly involved not only in the low-grade inflammatory status in obesity but also in other relevant inflammatory conditions and autoimmune disorders. In this review article, we discuss the main biological activities of leptin, adiponectin, lipocalin-2, resistin, and visfatin, as well as their contributions to certain inflammatory conditions.

Beyond fat mass: exploring the role of adipokines in rheumatic diseases

The cloning of leptin in 1994 by Zhang et al. introduced a novel concept about white adipose tissue (WAT) as a very dynamic organ that releases a plethora of immune and inflammatory mediators, such as adipokines and cytokines, which are involved in multiple diseases. Actually, adipokines exert potent modulatory actions on target tissues involved in rheumatic diseases including cartilage, synovial, bone and immune cells. The goal of this paper is to elucidate the recent findings concerning the involvement of adipokines in rheumatic diseases, such as rheumatoid arthritis (RA), osteoarthritis (OA), and systemic lupus erythematosus (SLE).

The role of resistin in Behçet's disease: a Turkish experiment

The objective of this study was to assess the role of resistin, a proinflammatory cytokine potentially involved in Behçet's disease (BD), and to determine its relationship with tumor necrosis factor α (TNF-α), another important inflammatory cytokine known to be involved in BD. Forty-five persons diagnosed with BD were enrolled into this study, 25 of whom were being followed or had recently been diagnosed with clinically active BD, whereas the remaining 20 were previously diagnosed and had clinically inactive BD for the previous 3 months. Thirty persons were recruited as a healthy control group. Patients' C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), resistin, and TNF-α levels were determined with enzyme-linked immunosorbent assay (ELISA). Resistin and TNF-α levels were significantly higher in patients with BD (p < 0.05 and p < 0.05) than in the control group. The major interest of this study was to investigate the role of resistin in patients with BD. An elevated resistin level was associated with activation of BD. Elevated TNF-α and resistin levels could be determined simultaneously, and the presence of these two cytokines together suggests that resistin plays an important role in the pathogenesis and activation of BD.

Interleukin-6 G-174C gene polymorphism and serum resistin levels in North Indian women: potential risk of metabolic syndrome

The present investigations were aimed to identify the possible association between genetic polymorphism in interleukin-6 (IL-6) G-174C gene, which confers susceptibility to metabolic syndrome, and serum level of resistin in North Indian women. The study population comprised 370 unrelated Indian women (192 having abdominal obesity and 178 controls). Polymorphism in genotype (CC+GC) of IL-6 G-174C gene was determined using a combination of polymerase chain reaction (PCR) and sequence-specific primer with restriction fragment length polymorphism (RFLP) technology. Insulin resistance (IR) and serum resistin level were also analyzed along with metabolic risk factors. Of 192 abdominal obese women, 147 (76.56%) were found to have mutant CC+GC (p = 0.001) genotype and allele frequency (p = 0.001), which was significantly higher 45 (23.44%) than non-obese and their respective wild type. The mutant genotype (CC+GC) of IL-6 gene was found to be associated significantly with high triglyceride (p = 0.025) and resistin level (p < 0.001), when compared with respective wild genotype (GG) in obese women. Non-obese women with no signs of metabolic risk factors were found to have significantly low level of serum resistin and IR in comparison to obese women having genetic polymorphism for IL-6 G-174C gene. Study suggests that IL-6 G-174C gene is one among the susceptibility loci for metabolic syndrome in North Indian women. Genotype for this polymorphism may prove informative for prediction of genetic risk for metabolic syndrome. Further, high level of serum resistin molecules may be targeted to correlate with metabolic syndrome risk factors and could be used as early prediction marker.

The potential interplay of adipokines with toll-like receptors in the development of hepatocellular carcinoma

Toll-like receptors (TLRs) are not only crucial to the initiation of the immune system, but also play a key role in several human inflammatory diseases. Hepatocellular carcinoma (HCC) is among those human cancers, which arise from sites of chronic inflammation. Therefore, a number of studies have explored the potential contribution of TLRs to HCC occurrence, which is initiated by exposure to chronic hepatic inflammation of different etiologies (including ethanol, and chronic B and C viral infections). Recent epidemiological data have shown the association of obesity and HCC development. Given the fact that adipose tissues can produce a variety of inflammation-related adipokines, obesity has been characterized as a state of chronic inflammation. Adipokines are therefore considered as important mediators linking inflammation to several metabolic diseases, including cancers. More recently, many experts have also shown the bridging role of TLRs between inflammation and metabolism. Hopefully, to retrieve the potential interaction between TLRs and adipokines in carcinogenesis of HCC will shed a new light on the therapeutic alternative for HCC. In this paper, the authors first review the respective roles of TLRs and adipokines, discuss their mutual interaction in chronic inflammation, and finally anticipate further investigations of this interaction in HCC development.

Association of circulating adiponectin levels with progression of radiographic joint destruction in rheumatoid arthritis

BACKGROUND

Adipokines have inflammatory and immunomodulatory properties that may contribute to erosive joint damage. The association of serum adipokine levels with progression of radiographic joint damage in patients with rheumatoid arthritis (RA) was prospectively explored.

METHODS

Patients with RA underwent serum adipokine assessment (adiponectin, resistin, leptin) at three timepoints and hand/feet x-rays, scored using the Sharp-van der Heijde Score (SHS), at baseline and the third study visit, separated by an average of 39±4 months. The associations of baseline and average adipokine levels with change in SHS were explored, adjusting for pertinent confounders.

RESULTS

Of the 152 patients studied, 85 (56%) showed an increase in SHS (defined as >0 SHS units). Among the adipokines studied, only adiponectin was significantly associated with radiographic progression, with average adiponectin levels more strongly associated than baseline levels. After adjusting for average C reactive protein and baseline SHS, patients in the highest quartile of average adiponectin had a SHS progression rate more than double the lowest quartile (1.00 vs 0.48 units/year; p=0.008). Similarly, those in the highest quartile of adiponectin had a more than fivefold greater odds of any radiographic progression compared with the lowest quartile (OR 5.75; p=0.002). The magnitude of the association of average adiponectin levels with radiographic progression was greater in women, those with body mass index <30 kg/m(2) and those receiving baseline biological disease-modifying antirheumatic drugs.

CONCLUSIONS

These prospective data provide evidence of temporality and dose-response in the relationship between circulating adiponectin and erosive joint destruction in RA, and highlight subgroups of patients at highest risk for adiponectin-associated radiographic progression.

Long-term in vivo resistin overexpression induces myocardial dysfunction and remodeling in rats

We have previously reported that resistin induces hypertrophy and impairs contractility in isolated rat cardiomyocytes. To examine the long-term cardiovascular effects of resistin, we induced in vivo overexpression of resistin using adeno-associated virus serotype 9 injected by tail vein in rats and compared to control animals. Ten weeks after viral injection, overexpression of resistin was associated with increased ratio of left ventricular (LV) weight/body weight, increased end-systolic LV volume and significant decrease in LV contractility, measured by the end-systolic pressure volume relationship slope in LV pressure volume loops, compared to controls. At the molecular level, mRNA expression of ANF and β-MHC, and protein levels of phospholamban were increased in the resistin group without a change in the level of SERCA2a protein expression. Increased fibrosis by histology, associated with increased mRNA levels of collagen, fibronectin and connective tissue growth factor were observed in the resistin-overexpressing hearts. Resistin overexpression was also associated with increased apoptosis in vivo, along with an apoptotic molecular phenotype in vivo and in vitro. Resistin-overexpressing LV tissue had higher levels of TNF-α receptor 1 and iNOS, and reduced levels of eNOS. Cardiomyocytes overexpressing resistin in vitro produced larger amounts of TNFα in the medium, had increased phosphorylation of IκBα and displayed increased intracellular reactive oxygen species (ROS) content with increased expression and activity of ROS-producing NADPH oxidases compared to controls. Long-term resistin overexpression is associated with a complex phenotype of oxidative stress, inflammation, fibrosis, apoptosis and myocardial remodeling and dysfunction in rats. This phenotype recapitulates key features of diabetic cardiomyopathy. This article is part of Special Issue Item Group entitled "Possible Editorial".

Resistin induces monocyte-endothelial cell adhesion by increasing ICAM-1 and VCAM-1 expression in endothelial cells via p38MAPK-dependent pathway

Resistin, firstly reported as an adipocyte-specific hormone, is suggested to be an important link between obesity and diabetes. Recent studies have suggested an association between resistin and atherogenic processes. The adhesion of circulating monocytes to endothelial cells is a critical step in the early stages of atherosclerosis. The purpose of the present study was to investigate the effect of resistin on the adhesion of THP-1 monocytes to human umbilical vein endothelial cells (HUVECs) and the underlying mechanism. Our results showed that resistin caused a significant increase in monocyte adhesion. In exploring the underlying mechanisms of resistin action, we found that resistin-induced monocyte adhesion was blocked by inhibition of p38MAPK activation using SB203580 and SB202190. Furthermore, resistin increased the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by HUVECs and these effects were also p38MAPK-dependent. Resistin-induced monocyte adhesion was also blocked by monoclonal antibodies against ICAM-1 and VCAM-1. Taken together, these results show that resistin increases both the expression of ICAM-1 and VCAM-1 by endothelial cells and monocyte adhesion to HUVECs via p38MAPK-dependent pathways.

Serum resistin level is associated with radiographic changes in hand osteoarthritis: cross-sectional study

OBJECTIVE

The aim of this study was to determine whether adipokines such as adiponectin and resistin were related to radiographic outcomes in patients with hand osteoarthritis (OA).

METHODS

A total of 156 female subjects (46 controls, 60 non-radiographic hand OA, and 50 radiographic hand OA) were enrolled. We measured serum adiponectin and resistin concentrations using an enzyme-linked immunosorbent assay (ELISA). Radiographic hand OA was defined by the presence of a ≥2 Kellgren-Lawrence radiological grade after assessment for 20 joints of both hands. The association between radiographic hand OA and each adipokine was assessed using multivariate logistic regression models controlling for confounding clinical parameters.

RESULTS

Serum resistin levels in radiographic hand OA patients were higher than in non-radiographic hand OA and controls (p(adj)=0.020 and p(adj)=0.019, respectively), whereas there were no significant differences in serum adiponectin levels. The presence of radiographic changes in hand OA was shown to be dependent on serum resistin levels (p(adj)=0.028). Specifically, subchondral erosion in radiographic hand OA was associated with serum resisitin (p(adj)=0.028). However, there were no associations of serum adipokines with joint space narrowing, bony ankylosis, and cortical destruction.

CONCLUSIONS

This study suggests that resistin is involved in radiographic changes in hand OA, and that adipokines contribute to pathogenesis in radiographic outcomes in hand OA.

No effect of physiotherapy on the serum levels of adipocytokines in patients with ankylosing spondylitis

To investigate the effect of intensive physiotherapy on disease activity and serum levels of adipocytokines in patients with ankylosing spondylitis (AS). Twenty-six patients with AS were included in this study. Intensive physiotherapy was performed twice a week for a period of 3 months. The Bath AS Disease Activity Index (BASDAI) and the Bath AS Functional Index (BASFI) were assessed at inclusion and after 3 months. Leptin, adiponectin, resistin and visfatin serum levels were analysed by ELISA assays. Patients had mild to moderate disease activity. Baseline levels of adipocytokines did not correlate with indicators of disease activity, functional status or acute-phase reactants. After the 3 months of intensive physiotherapy, BASDAI significantly decreased from 2.98 to 1.8 (p = 0.01) and BASFI improved from 2.31 to 1.37 (p = 0.05), while there were no changes in serum levels of CRP, ESR and adipocytokines. In addition, baseline levels of adipocytokines did not predict the change of disease activity or functional ability. Intensive physiotherapy effectively reduces all clinical measures of disease activity, but it is not associated with a significant change in acute-phase reactants or serum levels of adipocytokines.

Diabetes mellitus and insulin resistance in patients with rheumatoid arthritis: risk reduction in a chronic inflammatory disease

OBJECTIVE

To perform a systematic literature review of the potential association among molecular markers of inflammation, alterations in body composition, and insulin resistance (IR), a precursor to type 2 diabetes mellitus (DM), in rheumatoid arthritis (RA) patients. To determine the impact of tumor necrosis factor α (TNFα) as a pivotal proinflammatory cytokine in the pathophysiology of type 2 DM and RA, and the effect of antirheumatic drugs on glycemic control.

METHODS

We performed a search of PubMed to identify articles on IR and body habitus in patients with RA.

RESULTS

Patients with RA had characteristics placing them at high risk for IR and type 2 DM. The incidence and prevalence of type 2 DM in RA was not clearly increased compared with the general population; however, studies suggested that patients with RA are likely to have IR and have increased risk of cardiovascular disease (CVD). The prevalence of type 2 DM and IR could be estimated from reports of risk factors for CVD in RA patients. The TNFα antagonists provided rapid and effective control of RA-related inflammation. Evidence indicated that extended use of TNFα antagonists in RA may provide the additional benefit of improving insulin sensitivity. These treatment-related changes may contribute to an overall reduction in the risk of type 2 DM and CVD in RA patients.

CONCLUSION

Controlling inflammation may improve insulin sensitivity and subsequently reduce the risk of developing type 2 DM in RA patients. This may also reduce the risk of CVD in this high-risk group. Future studies are required to elucidate the relationships between inflammation, body composition, IR, TNFα antagonist use, and the risk of developing type 2 DM in RA patients.

The level of serum visfatin (PBEF) is associated with total number of B cells in patients with rheumatoid arthritis and decreases following B cell depletion therapy

OBJECTIVE

Visfatin, also known as pre-B cell colony-enhancing factor, was recently characterized as a potent pro-inflammatory mediator in rheumatoid arthritis (RA). The aim of this study was to determine the effect of B cell depletion with rituximab on serum visfatin levels in patients with active RA.

METHODS

We evaluated 31 patients with RA starting rituximab therapy at baseline and after 16 and 24 weeks using disease activity score (DAS28). The control group consisted of 33 gender and age-matched healthy individuals. CD19(+) B cells were assessed by flow cytometry and serum levels of visfatin and B cell-activating factor of the TNF family (BAFF) were measured by ELISA at baseline and week 16.

RESULTS

Total number of B cells correlated positively with serum visfatin levels (rs=0.417, P=0.025) and negatively with serum BAFF levels (rs=-0.486, P=0.008) at baseline. Serum visfatin levels were significantly higher in patients with RA compared with healthy controls (P=0.026), and significantly decreased (P=0.010), while BAFF increased (P<0.001), and both proteins became negatively correlated following treatment with rituximab (rs=-0.438, P=0.017). Visfatin levels did not correlate with the disease activity, but lack of change in the serum visfatin levels between baseline and week 16 predicted worsening disease activity between weeks 16 and 24 (rs=0.452, P=0.014).

CONCLUSION

In patients with active RA, serum visfatin levels are related to the number of B cells rather than to disease activity and decrease in response to treatment with rituximab. Further studies are necessary to show if visfatin is a marker with predictive value for deterioration of RA.

The metabolic syndrome: the crossroads between rheumatoid arthritis and cardiovascular risk

Rheumatoid arthritis (RA) patients have an incidence of cardiovascular (CV) diseases at least two times higher than the general population. Atherosclerosis, the main determinant of CV morbidity and mortality, and carotid intima-media thickness, an early preclinical marker of atherosclerosis, also occur early on in RA. Traditional CV risk factors seem to have the same prevalence in RA and non-RA patients, and thus do not fully explain the increased CV burden, suggesting that RA inflammation and therapies play a role in increasing CV risk in these patients. The metabolic syndrome and fat tissue are likely to be the major players in this complex network. The metabolic syndrome (MetS) represents a cluster of cardiovascular risk factors that have in common insulin resistance and increased visceral adiposity. This entity has received great attention in the last few years due to its contribution to the burden of cardiovascular morbidity and mortality. Moreover, recently the adipose tissue has emerged as a dynamic organ that releases several inflammatory and immune mediators (adipokines). The association of MetS and atherosclerosis is thought to be partly mediated by altered secretion of adipokines by the adipose tissue and, on the other hand, there are evidence that adipokines may play some role in inflammatory arthritides. Obesity is now regarded as a systemic, low-grade inflammatory state, and inflammation as a link between obesity, metabolic syndrome, and cardiovascular diseases. To obtain a full control of the CV risk, data suggest that it is therefore mandatory a "tight control" of both RA and MetS inflammations.

Adipokine resistin is a key player to modulate monocytes, endothelial cells, and smooth muscle cells, leading to progression of atherosclerosis in rabbit carotid artery

OBJECTIVES

We investigated the effects of human resistin on atherosclerotic progression and clarified its underlying mechanisms.

BACKGROUND

Resistin is an adipokine first identified as a mediator of insulin resistance in murine obesity models. But, its role in human pathology is under debate. Although a few recent studies suggested the relationship between resistin and atherosclerosis in humans, the causal relationship and underlying mechanism have not been clarified.

METHODS

We cloned rabbit resistin, which showed 78% identity to human resistin at the complementary deoxyribonucleic acid level, and its expression was examined in 3 different atherosclerotic rabbit models. To evaluate direct role of resistin on atherosclerosis, collared rabbit carotid arteries were used. Histological and cell biologic analyses were performed.

RESULTS

Rabbit resistin was expressed by macrophages of the plaque in the 3 different atherosclerotic models. Peri-adventitial resistin gene transfer induced macrophage infiltration and expression of various inflammatory cytokines, resulting in the acceleration of plaque growth and destabilization. In vitro experiments elucidated that resistin increased monocyte-endothelial cell adhesion by upregulating very late antigen-4 on monocytes and their counterpart vascular cell adhesion molecule-1 on endothelial cells. Resistin augmented monocyte infiltration in collagen by direct chemoattractive effect as well as by enhancing migration toward monocyte chemotactic protein-1. Administration of connecting segment-1 peptide, which blocks very late antigen-4 × vascular cell adhesion molecule-1 interaction, ameliorated neointimal growth induced by resistin in vivo.

CONCLUSIONS

Our results indicate that resistin aggravates atherosclerosis by stimulating monocytes, endothelial cells, and vascular smooth muscle cells to induce vascular inflammation. These findings provide the first insight on the causal relationship between resistin and atherosclerosis.

Resistin concentration is increased in the peritoneal fluid of women with endometriosis

PROBLEM

The aim of this study was to investigate the concentration of resistin and adiponectin in the peritoneal fluid (PF) of patients with endometriosis.

METHOD OF STUDY

PF sampling was obtained from women with (n = 48) and without endometriosis (n = 36), and the anthropometric indices of the patients were measured. Resistin and adiponectin concentrations in the PF were determined using the enzyme-linked immunosorbent assay.

RESULTS

The mean concentration of PF resistin was significantly higher in women with endometriosis compared to the controls. PF resistin concentrations were not associated with any of the anthropometric indices. The PF adiponectin did not differ between the two groups, but showed a significant association with the weight, body mass index, and hip circumference. After adjusting for these factors, PF adiponectin expression was not associated with endometriosis.

CONCLUSION

The findings of this study suggest a potent role for resistin in endometriosis. Further studies are needed to elucidate the biological implications of resistin in endometriosis.

Increased plasma levels of adipokines and inflammatory markers in older women with persistent HPV infection

We observed diminished lymphoproliferation to multiple stimuli in older women with persistent cervical human papillomavirus (HPV) infection. Adipokines are a class of inflammatory cytokines that are altered in some persistent infections. The objective was to compare the level of adipokines and inflammatory cytokines in heparinized plasma from women with persistent HPV cervical infection (Cases, N=50, oversampled for their weak lymphoproliferation responses) with women with no evidence of persistent HPV cervical infection (Controls, N=50, oversampled for their strong lymphoproliferation responses). Plasma samples were analyzed with multiplex assays for adipokines and inflammatory cytokines. Cases had significantly elevated plasma levels of resistin (p<0.0001) and sFas (p=0.0038) as compared to controls. Risk of persistent HPV infection increased significantly with increasing levels of resistin and 8Fas. This is the first study to demonstrate elevated levels of resistin and sFas in HPV persistently infected, older women with decreased immune function expanding the understanding of the systemic inflammation and immune alterations in individuals persistently infected with HPV. Further studies within a larger cohort are needed to define the generalities of these findings and any role adipokines have in persistent HPV infection.

The association of plasma resistin with dietary sodium manipulation, the renin-angiotensin-aldosterone system, and 25-hydroxyvitamin D3 in human hypertension

OBJECTIVE

Both resistin and vitamin D have been associated with the renin-angiotensin-aldosterone system (RAAS). We investigated the association between resistin and the RAAS, and resistin and vitamin D under controlled dietary sodium conditions.

DESIGN

Retrospective cross-sectional study of subjects from the HyperPATH Consortium, who were maintained in high dietary sodium (HS) and low dietary sodium (LS) balance for 1 week each.

PATIENTS

Caucasian subjects with hypertension (n=177).

MEASUREMENTS

25-Hydroxyvitamin D (25[OH]D) levels were used to assess vitamin D status. Plasma resistin and RAAS measures were evaluated on each dietary intervention.

RESULTS

Resistin levels were significantly higher in LS, where RAAS activity was high, when compared with HS balance, where RAAS activity was suppressed (6.36 vs 5.86 μg/l, P < 0.0001); however, resistin concentrations were not associated with plasma renin activity or serum aldosterone on either diet. 25(OH)D levels were positively and independently associated with resistin in both dietary conditions (HS: β=0.400, P-trend=0.027; LS: β=0.540, P-trend=0.014).

CONCLUSIONS

Dietary sodium loading reduced resistin levels, possibly by suppressing the RAAS; however, circulating RAAS components were not related to resistin concentrations within each specific dietary sodium condition. 25(OH)D was positively associated with resistin and may be involved in resistin regulation through an unknown mechanism. Further studies to understand resistin regulation in human hypertension better are warranted.

Inflammatory induction of human resistin causes insulin resistance in endotoxemic mice

OBJECTIVE

Although adipocyte-derived murine resistin links insulin resistance to obesity, the role of human resistin, predominantly expressed in mononuclear cells and induced by inflammatory signals, remains unclear. Given the mounting evidence that obesity and type 2 diabetes are inflammatory diseases, we sought to determine the relationship between inflammatory increases in human resistin and insulin resistance.

RESEARCH DESIGN AND METHODS

To investigate the role of human resistin on glucose homeostasis in inflammatory states, we generated mice lacking murine resistin but transgenic for a bacterial artificial chromosome containing human resistin (BAC-Retn), whose expression was similar to that in humans. The metabolic and molecular phenotypes of BAC-Retn mice were assessed after acute and chronic endotoxemia (i.e., exposure to inflammatory lipopolysaccharide).

RESULTS

We found that BAC-Retn mice have circulating resistin levels within the normal human range, and similar to humans, lipopolysaccharide markedly increased serum resistin levels. Acute endotoxemia caused hypoglycemia in mice lacking murine resistin, and this was attenuated in BAC-Retn mice. In addition, BAC-Retn mice developed severe hepatic insulin resistance under chronic endotoxemia, accompanied by increased inflammatory responses in liver and skeletal muscle.

CONCLUSIONS

These results strongly support the role of human resistin in the development of insulin resistance in inflammation. Thus, human resistin may link insulin resistance to inflammatory diseases such as obesity, type 2 diabetes, and atherosclerosis.

Resistin is an indicator of the metabolic syndrome according to five different definitions in the Finnish Health 2000 survey

BACKGROUND

Resistin is a peptide hormone secreted mainly from human monocytes and macrophages. It has an unclear association with the metabolic syndrome, which is a cluster of cardiovascular risk factors such as glucose intolerance, central obesity, insulin resistance, dyslipidemia, and hypertension. We examined the association of resistin with metabolic syndrome and its components in a population-based cohort.

METHODS

A subsample of a large Finnish cross-sectional health examination survey (the Health 2000 Survey) was studied. Resistin was measured using an in-house assay based on the DELFIA® technique in 1,508 Finnish men and women aged 45-74 years. Metabolic syndrome was defined according to five different definitions.

RESULTS

Resistin levels were higher in the subjects with metabolic syndrome when compared to the subjects without metabolic syndrome (P < 0.05 for every metabolic syndrome criterion). In logistic regression analysis, a high resistin level was an independent predictor of the prevalence of metabolic syndrome (P < 0.05 for every criterion). Resistin was positively associated with waist circumference, tumor necrosis factor-α, and insulin resistance assessed by the homeostasis model and inversely with total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol after adjusting for age, gender, and body mass index (P < 0.05 for all).

CONCLUSIONS

These results clarify the controversial association of resistin in obesity and metabolic syndrome, suggesting that a high resistin level is associated with clustering of metabolic disturbances.

Circulating adipokine levels in Portuguese patients with psoriasis vulgaris according to body mass index, severity and therapy

BACKGROUND

Psoriasis vulgaris is associated with overweight/obesity and with increased C-reactive protein (CRP), tumour necrosis factor (TNF)-α, interleukin (IL)-6, leptin and resistin levels and decreased adiponectin levels.

OBJECTIVES

To understand the role/relationship of adipokines, as well as CRP, in a Portuguese psoriatic population, by assessing the relationship of their levels with psoriasis severity, defined by Psoriasis Area and Severity Index (PASI), with obesity, defined by body mass index (BMI), and psoriasis therapy.

METHODS

A cross-sectional (n=66) and longitudinal study (before and after 12 weeks of therapy; n=44) was performed; 10 patients started topical treatment, 17 narrow-band ultraviolet B (NBUVB) and 17 psolaren associated with UVA (PUVA).

RESULTS

Patients presented significantly higher BMI, leptin, resistin, TNF-α, IL-6 and CRP and significantly lower adiponectin values. CRP and IL-6 correlated with PASI. Adiponectin and leptin were more altered in patients with higher BMI. Concerning severity, CRP, resistin and adiponectin were more altered in the severer forms. After treatment, a significant reduction in PASI, CRP, resistin, TNF-α and IL-6, and a significant rise in adiponectin were observed. Nonetheless, CRP and adiponectin remained different from those of control. Concerning therapies, topical therapy was not associated with any significant change, except for TNF-α. After NBUVB, a significant reduction was observed in TNF-α and in CRP. For PUVA, we observed a significant reduction in TNF-α, IL-6 and CRP, and a significant increase in adiponectin.

CONCLUSION

In psoriatic patients, increased overweight/obesity was associated with raised leptin levels and decreased adiponectin levels. Leptin may contribute to enhance the inflammatory process in overweight/obese psoriatic patients. Resistin, IL-6, CRP and adiponectin levels appear to be dependent on psoriasis severity. CRP, together with IL-6, appears to be a useful marker of psoriasis severity. Both NBUVB and PUVA were effective; however, PUVA results seem to be more successful. Nonetheless, after NBUVB and PUVA, a low-grade inflammation still persists.