Resistin, an adipokine with potent proinflammatory properties

Unravelling the adiponectin paradox: novel roles of adiponectin in the regulation of cardiovascular disease

Adipose tissue (AT) has recently been identified as a dynamic endocrine organ secreting a wide range of adipokines. Adiponectin is one such hormone, exerting endocrine and paracrine effects on the cardiovascular system. At a cellular and molecular level, adiponectin has anti-inflammatory, antioxidant and anti-apoptotic roles, thereby mitigating key mechanisms underlying cardiovascular disease (CVD) pathogenesis. However, adiponectin expression in human AT as well as its circulating levels are increased in advanced CVD states, and it is actually considered by many as a 'rescue hormone'. Due to the complex mechanisms regulating adiponectin's biosynthesis in the human AT, measurement of its levels as a biomarker in CVD is highly controversial, given that adiponectin exerts protective effects on the cardiovascular system but at the same time its increased levels flag advanced CVD. In this review article, we present the involvement of adiponectin in CVD pathogenesis and we discuss its role as a clinical biomarker.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Metabolic control of immune tolerance in health and autoimmunity

The filed that links immunity and metabolism is rapidly expanding. The adipose tissue, by secreting a series of immune regulators called adipokines, represents the common mediator linking metabolic processes and immune system functions. The dysregulation of adipokine secretion, occurring in obese individuals or in conditions of malnutrition or dietary restriction, affects the activity of immune cells resulting in inflammatory autoimmune responses or increased susceptibility to infectious diseases. Alterations of cell metabolism that characterize several autoimmune diseases strongly support the idea that the immune tolerance is also regulated by metabolic pathways. The comprehension of the molecular mechanisms underlying these alterations may lead to the development of novel therapeutic strategies to control immune cell differentiation and function in conditions of autoimmunity.

Increased Ghrelin Levels and Unchanged Adipocytokine Levels in Major Depressive Disorder

OBJECTIVE

One of the hypotheses of the pathophysiology of major depressive disorder (MDD) proposes that there is a relationship between adipocytokine and ghrelin levels and depression.

METHODS

Patients with major depression with a BMI ≤25 kg/m² between the ages of 11 and 18 years (n = 30) were compared with a healthy control group (n = 30). Both groups were evaluated across a pretreatment period (MD-PT) and an improved period (MD-I). We measured serum leptin, adiponectin, resistin, and ghrelin levels and other parameters related to metabolic syndrome, such as glucose, insulin, insulin resistance (homeostasis model assessment [HOMA]), triglycerides (TG), and total cholesterol (TCHOL).

RESULTS

Leptin, adiponectin, and resistin levels did not differ across groups; however, ghrelin levels were increased in the MD-I group compared with the control and MD-PT groups (p < 0.05). HOMA levels were also higher in the MD-PT group than in the control group (p < 0.05). After treatment, there was no difference in this measurement.

CONCLUSIONS

The relationship between adipocytokines and major depression may be dependent on ghrelin levels as a result of antidepressant treatment and subsequent obesity.

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.

Resistin Promotes Intervertebral Disc Degeneration by Upregulation of ADAMTS-5 Through p38 MAPK Signaling Pathway

STUDY DESIGN

Rat nucleus pulposus (NP) cells were activated with resistin with or without p38 mitogen-activated protein kinase (MAPK) pathway inhibition. The expression of a disintegrin and metalloprotease with thrombospondin motif-5 (ADAMTS-5), which plays an important role in intervertebral disc degeneration (IDD), was determined.

OBJECTIVE

The aim of this study was to demonstrate whether resistin can influence the ADAMTS-5 expression and to further investigate the underlying mechanisms.

SUMMARY OF BACKGROUND DATA

Obesity has been demonstrated to promote IDD, whereas the exact mechanism remains poorly understood. Resistin, as an important adipokine, is increased with obesity and has been shown to play pro-inflammatory and catabolic role in cartilage metabolism. However, the effect of resistin on the catabolic enzymes within NP cells remains unknown.

METHODS

We exposed NP cells to resistin, and the transcriptional activity, gene expression, and protein levels of ADAMTS-5 were measured by luciferase reporter assay, qRT-polymerase chain reaction, immunofluorescence, and western blot, respectively. The activation of p38 MAPK pathways was detected using western blot analysis.

RESULTS

Resistin had no effect on cell viability. Resistin increased ADAMTS-5 expression in rat NP cells time and dose dependently. The p38 MAPK signaling pathway was activated after exposure to resistin. Treatment with p38 inhibitor decreased the upregulation of ADAMTS-5 by resistin.

CONCLUSION

The current study, for the first time, investigated the role of resistin in ADAMTS-5 regulation in IDD. These findings provide novel evidence supporting the causative role of obesity in IDD, which is important to develop novel preventative or therapeutic treatment in disc degenerative disorders.

LEVEL OF EVIDENCE

N/A.

Association of Vitamin B12 with Pro-Inflammatory Cytokines and Biochemical Markers Related to Cardiometabolic Risk in Saudi Subjects

Background: This study aimed to examine the relationship between changes in systemic vitamin B12 concentrations with pro-inflammatory cytokines, anthropometric factors and biochemical markers of cardiometabolic risk in a Saudi population. Methods: A total of 364 subjects (224 children, age: 12.99 ± 2.73 (mean ± SD) years; BMI: 20.07 ± 4.92 kg/m² and 140 adults, age: 41.87 ± 8.82 years; BMI: 31.65 ± 5.77 kg/m²) were studied. Fasting blood, anthropometric and biochemical data were collected. Serum cytokines were quantified using multiplex assay kits and B12 concentrations were measured using immunoassay analyzer. Results: Vitamin B12 was negatively associated with TNF-α (r = −0.14, p < 0.05), insulin (r = −0.230, p < 0.01) and HOMA-IR (r = −0.252, p < 0.01) in all subjects. In children, vitamin B12 was negatively associated with serum resistin (r = −0.160, p < 0.01), insulin (r = −0.248, p < 0.01), HOMA-IR (r = −0.261, p < 0.01). In adults, vitamin B12 was negatively associated with TNF-α (r = −0.242, p < 0.01) while positively associated with resistin (r = 0.248, p < 0.01). Serum resistin was the most significant predictor for circulating vitamin B12 in all subjects (r² = −0.17, p < 0.05) and in children (r² = −0.167, p < 0.01) while HDL-cholesterol was the predictor of B12 in adults (r² = −0.78, p < 0.05). Conclusions: Serum vitamin B12 concentrations were associated with pro-inflammatory cytokines and biochemical markers of cardiometabolic risks in adults. Maintaining adequate vitamin B12 concentrations may lower inflammation-induced cardiometabolic risk in the Saudi adult population.

Resistin-induced cardiomyocyte hypertrophy is inhibited by apelin through the inactivation of extracellular signal-regulated kinase signaling pathway in H9c2 embryonic rat cardiomyocytes

It has been reported that resistin induces, whereas apelin inhibits cardiac hypertrophy. However, the underlying molecular mechanisms of apelin inhibiting resistin-induced cardiac hypertrophy remain unclear. The aim of the current study is to investigate the effects of apelin on resistin-induced cardiomyocyte hypertrophy and elucidate the underlying molecular mechanism. H9c2 cells were used in the present study, and cell surface area and protein synthesis were evaluated. Reverse transcription-quantitative polymerase chain reaction was performed to analyze the expression levels of hypertrophic markers, brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC). In addition, western blotting was conducted to examine phosphorylation of extracellular signal-regulated kinase (ERK)1/2. Following treatment of H9c2 cells with resistin, cell surface area, protein synthesis, and BNP and β-MHC mRNA expression levels were increased. Subsequent to co-treatment of H9c2 cells with apelin and resistin, lead to the inhibition of resistin-induced hypertrophic effects by apelin. In addition, treatment with resistin increased phosphorylation of ERK1/2, whereas pretreatment with apelin decreased phosphorylation of ERK1/2, which was increased by resistin. These results indicate that resistin-induced cardiac hypertrophy is inhibited by apelin via inactivation of ERK1/2 cell signaling.

Micronutrient Antioxidants and Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most important chronic liver diseases worldwide and has garnered increasing attention in recent decades. NAFLD is characterized by a wide range of liver changes, from simple steatosis to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. The blurred pathogenesis of NAFLD is very complicated and involves lipid accumulation, insulin resistance, inflammation, and fibrogenesis. NAFLD is closely associated with complications such as obesity, diabetes, steatohepatitis, and liver fibrosis. During the progression of NAFLD, reactive oxygen species (ROS) are activated and induce oxidative stress. Recent attempts at establishing effective NAFLD therapy have identified potential micronutrient antioxidants that may reduce the accumulation of ROS and finally ameliorate the disease. In this review, we present the molecular mechanisms involved in the pathogenesis of NAFLD and introduce some dietary antioxidants that may be used to prevent or cure NAFLD, such as vitamin D, E, and astaxanthin.

Investigating the role of adipokines in chronic migraine

Background and aims

Adiponectin, leptin, and resistin are adipocyte-derived secretory factors involved in endothelial function, weight, inflammation, and insulin resistance. Recent studies suggested a role for adipokines in episodic migraine as mediators of inflammatory processes. The aim of this study was to investigate plasma concentrations of adiponectin, leptin, and resistin in patients with chronic migraine.

Materials and methods

Twenty-seven chronic migraineurs (20 females, 7 males; mean age 49.0 ± 9.0 yrs) and 37 healthy controls (23 females, 14 males; mean age 49.8 ± 15.0 yrs) were selected for the study. Fasting plasmatic levels of total adiponectin, leptin, and resistin were measured using ELISA kits during a pain-free period. Fasting glucose, insulin, total and HDL-cholesterol, triglycerides, and ESR were also determined.

Results

Serum levels of adiponectin and resistin were significantly increased in chronic migraineurs in comparison with controls ( p = 0.001 and p = 0.032, respectively). After correction for BMI, sex and age, leptin levels were significantly increased in chronic migraineurs ( p = 0.007). A positive correlation between leptin concentrations and both indices of insulin resistance and markers of inflammation was found.

Discussion

Our data suggest that adiponectin and resistin are altered in non-obese chronic migraineurs. Further studies are needed to elucidate the neurobiological mechanisms underlying adipokine dysfunction in migraine.

Metabolic aspects of adult patients with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease and it encompasses a spectrum from simple steatosis to steatohepatitis, fibrosis, or cirrhosis. The mechanisms involved in the occurrence of NAFLD and its progression are probably due to a metabolic profile expressed within the context of a genetic predisposition and is associated with a higher energy intake. The metabolic syndrome (MS) is a cluster of metabolic alterations associated with an increased risk for the development of cardiovascular diseases and diabetes. NAFLD patients have more than one feature of the MS, and now they are considered the hepatic components of the MS. Several scientific advances in understanding the association between NAFLD and MS have identified insulin resistance (IR) as the key aspect in the pathophysiology of both diseases. In the multi parallel hits theory of NAFLD pathogenesis, IR was described to be central in the predisposition of hepatocytes to be susceptible to other multiple pathogenetic factors. The recent knowledge gained from these advances can be applied clinically in the prevention and management of NAFLD and its associated metabolic changes. The present review analyses the current literature and highlights the new evidence on the metabolic aspects in the adult patients with NAFLD.

PKCε mediates resistin-induced NADPH oxidase activation and inflammation leading to smooth muscle cell dysfunction and intimal hyperplasia

BACKGROUND AND AIMS

Resistin has been implicated in cardiovascular disease and poor interventional cardiovascular outcomes. Previous studies by our group demonstrated resistin promoted vascular smooth muscle cell (VSMC) migration through protein kinase C epsilon (PKCε) pathways, while few others showed that resistin induced reactive oxygen species (ROS) generation in various cell types. In this study, we aim to systemically examine the functional role of resistin at the cellular and tissue levels as well as the potential mechanistic relationship between resistin-induced PKCε activation and ROS production.

METHODS

Plasma collected from patients undergoing carotid interventions was analyzed for resistin level and ROS. VSMCs were treated with resistin in the presence or absence of PKCε and NADPH oxidase (Nox)-specific inhibitors. Intracellular ROS production was analyzed using confocal microscopy and Nox activity with chemiluminescence. In vivo studies were performed in apolipoprotein E knock out (ApoE^-/-) mice to determine therapeutic effects of PKCε-specific inhibitor, using the guide-wire injury model.

RESULTS

We observed significant correlation between plasma resistin and circulating levels of oxidative stress in patients with severe atherosclerotic disease. We also demonstrated that resistin induced ROS production via PKCε-mediated Nox activation. Resistin-induced ROS production was time-dependent, and Nox4 was the primary isoform involved. Inhibition of Nox completely abolished resistin-exaggerated VSMC proliferation, migration and dedifferentiation, as well as pro-inflammatory cytokine release. Upstream modulation of PKCε significantly reduced resistin-mediated cytosolic ROS, Nox activity and VSMC dysfunction. Moreover, PKCε-specific inhibitor mitigated resistin-induced Nox activation and intimal hyperplasia in ApoE^-/- mice.

CONCLUSIONS

Resistin-associated VSMC dysfunction and intimal hyperplasia are related to PKCε-dependent Nox activation and ROS generation. Targeting the PKCε-Nox pathway may represent a novel strategy in managing resistin-associated atherosclerotic complications.

Resistin as potential biomarker for chronic periodontitis: A systematic review and meta-analysis

OBJECTIVES

To determine the serum and gingival crevicular fluid (GCF) levels of resistin between individuals with chronic periodontitis (CP) and those without CP, and to evaluate the role of resistin in CP.

MATERIALS AND METHODS

The addressed focused question was "Is there a difference in the resistin levels between individuals with CP and those without CP?" four electronic databases: Medline, PubMed (National Institutes of Health, Bethesda), EMBASE, and Science direct databases from 1977 up to March 2016 for appropriate articles addressing the focused question. EMBASE and Medline were accessed using OVID interface which facilitated simultaneous search of text words, MeSH or Emtree. Unpublished studies (gray literature) were identified by searching the Open-GRAY database and references of the included studies (cross referencing) were performed to obtain new studies. In-vitro studies, animal studies, studies that reported levels of other cytokines but not resistin, letters to the editor and review papers were excluded.

RESULTS

Ten studies were included. Nine studies compared resistin levels between CP and periodontally healthy (H) individuals and reported higher mean serum and GCF levels of resistin in CP patients than the H controls. Two studies showed comparable resistin levels from GCF and serum between diabetes mellitus with CP (DMCP) and CP groups. Three studies included obese subjects and showed comparable serum and GCF resistin levels between obese subjects with CP (OBCP) and CP subjects.

CONCLUSIONS

CP patients were presented with elevated levels of GCF or serum resistin as compared with H individuals. Resistin modulates inflammation in chronic periodontal disease and may be used as surrogate measure to identify subjects at risk for periodontitis. Resistin levels in patients with CP and systemic inflammatory disorders such as diabetes, obesity, or rheumatoid arthritis was not significantly higher than the levels in patients with only CP.

Transcriptomic Profiling of Adipose Tissue in Obese Women in Response to Acupuncture Catgut Embedding Therapy with Moxibustion

OBJECTIVE

Complementary and alternative medicine, such as Traditional Chinese Medicine, represents an efficient therapeutic option for obesity control. It was previously reported that acupuncture catgut embedding therapy (ACET) with moxibustion reduces body weight and reverts insulin resistance in obese women. This study aimed to evidence changes in adipokines and gene expression in adipose tissue that could explain the effects of ACET with moxibustion.

DESIGN

Overweight/obese women were treated with ACET with moxibustion or sham acupuncture as control. Peripheral blood samples and fat biopsies were taken before and after intervention. Circulating adipokines (leptin, adiponectin, tumor necrosis factor alpha, and resistin) were quantified by enzyme-linked immunosorbent assay. Gene expression in adipose tissue was determined by cDNA microarray assays and assessed by quantitative reverse transcription real-time polymerase chain reaction.

RESULTS

ACET with moxibustion did not modify circulating adipokines levels. However, correlations with anthropometric and biochemical parameters were affected. Interestingly, transcriptional changes in adipose tissue revealed the modulation of genes participating in homeostasis control, lipid metabolism, olfactory transduction, and gamma-aminobutyric acid signaling pathway.

CONCLUSIONS

The effects of ACET with moxibustion on body weight and insulin resistance were associated with the regulation of biochemical events that are altered in obesity.

Adipokines in nonalcoholic fatty liver disease

Since the discovery of adipose tissue as a higly active endocrine tissue, adipokines, peptides produced by adipose tissue and exerting autocrine, paracrine and endocrine function, have gained increasing interest in various obesity-related diseases, including nonalcoholic fatty liver disease (NAFLD). Data regarding the association between NAFLD and circulating leptin and adiponectin levels are generally well documented: leptin levels increase, whereas adiponectin levels decrease, by increasing the severity of NAFLD. Data regarding other adipokines in histologically confirmed NAFLD populations are inconclusive (e.g., resistin, visfatin, retinol-binding protein-4, chemerin) or limited (e.g., adipsin, obestatin, omentin, vaspin etc.). This review summarizes evidence on the association between adipokines and NAFLD. The first part of the review provides general consideration on the interplay between adipokines and NAFLD, and the second part provides evidence on specific adipokines possibly involved in NAFLD pathogenesis. A thorough insight into the pathophysiologic mechanisms linking adipokines with NAFLD may result in the design of studies investigating the combined adipokine use as noninvasive diagnostic markers of NAFLD and new clinical trials targeting the treatment of NAFLD.

Adipokine Gene Single-Nucleotide Polymorphisms in Portuguese Obese Adolescents: Associations with Plasma Concentrations of Adiponectin, Resistin, IL-6, IL-1β, and TNF-α

BACKGROUND

The genetic contribution to obesity and to circulating adipokine levels has not been completely clarified. We aimed to evaluate adipokine genes' single-nucleotide polymorphism (SNP) prevalence and its association with circulating adipokine levels and risk factors for cardiovascular disease in an obese Portuguese pediatric population.

METHODS

Two hundred forty-eight obese adolescents (mean age 13.4 years old; 47.2% females) participated in a cohort study. We screened 12 SNPs by direct sequencing in five adipokine genes: adiponectin (ADIPOQ: rs16861194, rs17300539, rs266729, rs2241766, rs1501299), interleukin-1β (IL-1β; rs1143627), IL-6 (IL-6; rs1800795), tumor necrosis factor-α (TNF-α; rs1800629), and resistin (RETN; rs1862513, rs3219177, rs3745367, rs3745368). Biochemical analysis included determination of circulating adipokines, C-reactive protein (CRP) levels, lipid profile, and markers of insulin resistance.

RESULTS

Compared to males, females presented higher circulating levels of insulin, adiponectin, IL-6, resistin, and leptin concentrations, but lower TNF-α levels. No statistically significant differences were found for genotype or allelic distributions between genders. In the whole sample population, adiponectin levels were influenced by ADIPOQ rs17300539 (c.-1138G>A; lower in subjects with GG genotype). When only males were considered, IL-1β, IL-6, and TNF-α levels were associated with ADIPOQ rs1501299 (c.214 + 62G>T; higher in GG subjects). TNF-α concentrations were modulated by TNF-α rs1800629 (c.-488G>A; lower in GG males), RETN rs1862513 (c.-216C>G; higher in CC subjects), and RETN rs3219177 (c.118 + 39C>T; higher in CC subjects). Leptin levels were influenced by IL-1β rs1143627 (c.-118C>T) presenting TT individuals' lower levels.

CONCLUSIONS

Our data demonstrate that in pediatric obese patients, some adipokine gene SNPs have an association with circulating adipokine levels and lipid profile.

Adipokines, tumor necrosis factor and its receptors in female patients with systemic lupus erythematosus

OBJECTIVES

To analyze the association of adipokines and tumor necrosis factor α (TNFα) and its receptors with characteristics of systemic lupus erythematosus (SLE) and to investigate the correlation between adipokines and the TNF system.

METHODS

One hundred and thirty-six SLE women, aged ≥18 years old, were assessed. TNFα, soluble TNFα receptors 1 (sTNFR1) and 2 (sTNFR2) and adipokines were analyzed by ELISA kits.

RESULTS

The median (IQR) of age was 41.5 (33.0-49.7) years old and of disease duration 11.3 (7.8-15.8) years. The median (IQR) of disease activity was 0 (0-4) and of damage index was 2 (1-3). Higher levels of sTNFR1 and sTNFR2 were associated with nephritis (p < 0.001 for both), and sTNFR1 (p = 0.025) and TNFα (p = 0.014) were positively associated with arthritis. Higher sTNFR1 levels were found in participants that were not using antimalarial drugs (p = 0.04). Independent correlation was found between sTNFR1 (β = 0.253; p = 0.003) and sTNFR2 (β = 0.297; p < 0.001) levels and disease activity and damage index (sTNFR1: β = 0.367; p < 0.001; sTNFR2: β = 0.335; p < 0.001). Higher adiponectin levels were independently associated with nephritis (p = 0.009) and antimalarial drugs use (p = 0.015). There was a positive correlation between leptin and sTNFR2 levels (p = 0.002) and between resistin levels and sTNFR1 (p < 0.001) and sTNFR2 (p < 0.001).

CONCLUSION

The correlation between adipokines and TNF system allows a better understanding of the role of adipokines in the inflammatory response in SLE patients.

Serum adipokines levels in patients with systemic sclerosis: A meta-analysis

BACKGROUND

Systemic sclerosis is an chronic inflammatory autoimmune diseases. Adipokine has been reported to play an important role in modulating immune responses. Recent studies suggest that adipokine also plays some roles in the pathogenesis of systemic sclerosis (SSc). However, published data regarding the relationship between plasma/serum adipokine levels and SSc are contradictory. The aim of this study was at performing a meta-analysis to derive a more accurate estimation and further investigate the association of plasma/serum leptin and adiponectin levels with SSc patients.

METHODS

PubMed, and Web of Science databases (up to Feb 20, 2016) were used to obtain all relative published literatures. The study quality was assessed by the Newcastle-Ottawa scale. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by random-effect model analysis.

RESULTS

A total of fourteen studies were finally included in this meta-analysis. Among them, six of which were studied for the serum adiponectin levels in SSc patients, six of which were studied for the serum leptin levels in SSc patients, and two of them were studied both for serum adiponectin levels and serum leptin levels in SSc patients. The meta-analysis results showed that the serum adiponectin levels in SSc patients were significantly lower than that in normal controls (SMD = -0.608 ng/ml, 95% CI = -1.029 to -0.186, p = 0.005). However, there were no significant differences in serum leptin levels between SSc patients and healthy controls (SMD = -0.990 ng/ml, 95% CI = -2.340 to 0.359, p = 0.150). The subgroup analysis showed that Asia SSc patients with age less than 50 years old had lower plasma/serum adiponectin levels when compared with controls.

CONCLUSION

The serum adiponectin levels, but not serum leptin levels, in SSc patients were significantly lower than that in normal controls.

Elevated plasma tumor necrosis factor-α receptor 2 and resistin are associated with increased incidence of kidney function decline in Chinese adults

Adipokines and inflammatory markers have been linked to kidney disease in animal models; however, evidence from prospective human studies is sparse. Recruited from Beijing and Shanghai in 2005, a total number of 2220 non-institutionalized Chinese individuals aged 50-70 years with baseline estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m(2) were prospectively followed for 6 years. Plasma levels of resistin, retinol-binding protein 4 (RBP4), interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-α receptor 2 (TNF-R2) were determined at baseline. Kidney function decrease was assessed by measurements of eGFR over 6 years. Incident-reduced eGFR was defined as the onset of eGFR <60 mL/min/1.73 m(2), according to the Modification of Diet in Renal Disease Study Equation for Chinese. During the 6 years of follow-up, 333 (15.0 %) participants had incident-reduced eGFR. Each 1 standard deviation elevated concentration of resistin [relative risk (RR) 1.10; 95 % CI 1.00-1.24] and TNFR-2 (RR 1.30; 95 % CI 1.13-1.49) at baseline were significantly associated with a higher risk of incident-reduced eGFR. Comparing the highest with the lowest quartiles, the RR of incident-reduced eGFR was 1.43 (95 % CI 1.01-2.03) for resistin and 2.03 (95 % CI 1.41-2.93) for TNF-R2 (both P trend < 0.05) after adjustment for baseline demographic characteristics, lifestyle behaviors, BMI, plasma lipid profile, hypertension, and diabetes. These associations remained significant when further controlling for levels of RBP4, IL-6, and CRP, none of which was significantly associated with the risk of incident-reduced eGFR. In this prospective cohort study, elevated levels of resistin and TNF-R2, but not other adipokines and inflammatory markers, were independently associated with a greater risk of kidney function decline in middle-aged and elderly Chinese.

The relationship between serum adipocytokines and Graves' ophthalmopathy: A hospital-based study

Adipocytokines are thought to be associated with inflammatory disorders and autoimmune diseases. However, limited information is available on the relationship between serum adipocytokine levels, Graves' disease (GD), and Graves' ophthalmopathy (GO). The present study examined the relationship between serum adipocytokine levels and GD and GO. A total of 80 patients with GD participated in this study. The medical records of patients were reviewed retrospectively. GO activity was assessed using the clinical activity score (CAS). GO severity was assessed by the modified NOSPECS classification and included soft tissue involvement, proptosis, and extraocular muscle involvement. Serum adiponectin, leptin, resistin, and retinol-binding protein 4 (RBP-4) levels were measured using commercially available enzyme-linked immunosorbent assays. The prevalence of GO was 36.3%. Serum adiponectin, leptin, and resistin levels were significantly higher in patients with GO than in those without GO. The CAS was positively correlated with serum adiponectin and leptin levels. The total eye score was positively correlated with serum adiponectin, leptin, resistin, and RBP-4 levels. A multivariate analysis revealed that serum leptin and resistin levels were associated with the presence of GO after adjusting for clinical factors. Free thyroxine was negatively correlated with serum leptin level. These results suggest that adipocytokines, such as leptin and resistin, may play a role in inflammatory and autoimmune processes of GD and GO. Future studies with larger numbers of patients are required to establish relationships between serum adipocytokines levels and GO and ascertain the role of adipocytokines in GD and GO.

The triad psoriasis-obesity-adipokine profile

Psoriasis is a chronic inflammatory skin disease, often associated with overweight/obesity. The adipose tissue is a complex organ that secretes several adipokines, involved in the regulation of some metabolic processes, such as lipid metabolism, glucose homeostasis, angiogenesis, blood pressure and inflammation. In obesity, the distribution and function of adipose tissue, and the adipokine profile are altered. The unbalanced production of pro- and anti-inflammatory adipokines in obesity, contributes to the development of a chronic low-grade inflammation state, which seems to favour worsening of psoriasis lesion and a poorer response to treatment. In this review, we will debate published data concerning the current knowledge about the triad psoriasis-obesity-adipokine profile.

[Influence of integrated traditional Chinese and Western medicine therapy on serum resistin levels in patients with severe acute pancreatitis: a randomized controlled trial]

BACKGROUND

Resistin level is high in patients with severe acute pancreatitis (SAP), and resistin is expected to be a new marker for evaluating the severity of acute pancreatitis.

OBJECTIVE

To explore the influence of integrated traditional Chinese and Western medicine therapy on serum resistin levels in SAP patients.

DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS

Twenty-eight SAP patients meeting inclusion criteria from Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University were included, and the patients were randomly divided into treatment group and placebo group. There were 13 patients in the treatment group and 15 patients in the placebo group. Patients in the treatment group were given traditional Chinese herbal medicine in addition to the conventional treatment. Patients in the placebo group were given placebo in addition to the conventional treatment.

MAIN OUTCOME MEASURES

The serum resistin levels on admission, and days 1, 3, 5, and 7 after the admission were detected.

RESULTS

The serum resistin levels on admission in all the patients were higher than normal level, and there was no significant difference between the two groups (P>0.05). On days 1, 3, 5, and 7 after admission, the resistin levels in the treatment group were (3.29 + or - 1.66) microg/L, (3.71 + or - 1.05) microg/L, (3.08 + or - 1.47) microg/L and (3.62 + or - 1.67) microg/L, and in the control group (5.16 + or - 1.93) microg/L, (5.07 + or - 1.53) microg/L, (4.88 + or - 1.47) microg/L and (5.12 + or - 1.48) microg/L, respectively. The resistin levels were lower in the treatment group than in the control group (P<0.05).

CONCLUSION

Serum resistin level in SAP patients can be decreased by integrated traditional Chinese medicine and Western medicine therapy.

An update on the role of adipokines in arterial stiffness and hypertension

Adipokines are hormones produced by adipocytes and have been involved in multiple pathologic pathways, including inflammatory and cardiovascular complications in essential hypertension. Arterial stiffness is a frequent vascular complication that represents increased cardiovascular risk in hypertensive patients. Adipokines, such as adiponectin, leptin and resistin, might be implicated in hypertension, as well as in vascular alterations associated with this condition. Arterial stiffness has proven to be a predictor of cardiovascular events. Obesity and target-organ damage such as arterial stiffness are features associated with hypertension. This review aims to update the association between adipokines and arterial stiffness in essential and resistant hypertension (RHTN).

Secret talk between adipose tissue and central nervous system via secreted factors-an emerging frontier in the neurodegenerative research

First seen as a storage organ, the white adipose tissue (WAT) is now considered as an endocrine organ. WAT can produce an array of bioactive factors known as adipokines acting at physiological level and playing a vital role in energy metabolism as well as in immune response. The global effect of adipokines in metabolic activities is well established, but their impact on the physiology and the pathophysiology of the central nervous system (CNS) remains poorly defined. Adipokines are not only produced by the WAT but can also be expressed in the CNS where receptors for these factors are present. When produced in periphery and to affect the CNS, these factors may either cross the blood brain barrier (BBB) or modify the BBB physiology by acting on cells forming the BBB. Adipokines could regulate neuroinflammation and oxidative stress which are two major physiological processes involved in neurodegeneration and are associated with many chronic neurodegenerative diseases. In this review, we focus on four important adipokines (leptin, resistin, adiponectin, and TNFα) and one lipokine (lysophosphatidic acid-LPA) associated with autotaxin, its producing enzyme. Their potential effects on neurodegeneration and brain repair (neurogenesis) will be discussed. Understanding and regulating these adipokines could be an interesting lead to novel therapeutic strategy in order to counteract neurodegenerative disorders and/or promote brain repair.

Biomolecular features of inflammation in obese rheumatoid arthritis patients: management considerations

Adipose tissue is an active organ playing a role not only in metabolism but also in immune and inflammatory processes, releasing several pro-inflammatory mediators. This can explain the possible association between obesity and rheumatoid arthritis (RA) and its role in the progression of the disease. Adipose and synovial tissues share common histological features of local inflammation in terms of activation of target tissues infiltrating cells (i.e. myeloid cells). Among the so-called adipocytokines, PEDF and Chemerin orchestrate the cellular cross-talk between adipose and myeloid cells, being possible biomarkers to monitor the effect of weight loss or the decrease of adipose tissue in patients with RA. Moreover, dietary intervention has been demonstrated to reduce Chemerin as well as IL-6 and MCP-1 expression. Finally, epigenetic regulators such as micro-RNAs (i.e. miR-155) are key regulators of myeloid cells activation in RA and obesity as well as in adipocytes. In this review, we will summarize the biological link between obesity/overweight state and RA focusing on pathophysiological mechanisms, consequences and management considerations.

Increased resistin levels in the serum and cerebrospinal fluid of patients with neuromyelitis optica

INTRODUCTION

Resistin, which acts as a pro-inflammatory cytokine, has been implicated in the pathogenesis of several autoimmune diseases. However, the involvement of resistin in neuromyelitis optica (NMO), a severe inflammatory central nervous system disorder that targets the optic nerve and spinal cord, remains unclear.

METHODS

We measured serum and cerebrospinal fluid (CSF) resistin levels in patients with NMO and controls matched by age and sex. The link between resistin levels and clinical variables in NMO was subsequently assessed.

RESULTS

The concentrations of serum and CSF resistin were significantly higher in patients with NMO than in controls, and decreased following treatment with methylprednisolone. High sensitivity C-reactive protein (hs-CRP) levels and annualized relapse rate positively correlated with resistin levels in patients with NMO.

CONCLUSION

Resistin might be a useful biomarker of inflammation in NMO, and a potential target for the treatment of NMO.

Biomarkers of hypoxia, endothelial and circulatory dysfunction among climbers in Nepal with AMS and HAPE: a prospective case-control study

BACKGROUND

The mechanisms underlying acute mountain sickness (AMS) and high-altitude pulmonary edema (HAPE) are not fully understood. We hypothesized that regulators of endothelial function, circulatory homeostasis, hypoxia and cell stress contribute to the pathobiology of AMS and HAPE.

METHODS

We conducted a prospective case-control study of climbers developing altitude illness who were evacuated to the CIWEC clinic in Kathmandu, compared to healthy acclimatized climbers. ELISA was used to measure plasma biomarkers of the above pathways.

RESULTS

Of the 175 participants, there were 71 cases of HAPE, 54 cases of AMS and 50 acclimatized controls (ACs). Markers of endothelial function were associated with HAPE: circulating levels of endothelin-1 (ET-1) were significantly elevated and levels of sKDR (soluble kinase domain receptor) were significantly decreased in cases of HAPE compared to AC or AMS. ET-1 levels were associated with disease severity as indicated by oxygen saturation. Angiopoietin-like 4 (Angptl4) and resistin, a marker of cell stress, were associated with AMS and HAPE irrespective of severity. Corin and angiotensin converting enzyme, regulators of volume homeostasis, were significantly decreased in HAPE compared to AC.

CONCLUSION

Our findings indicate that regulators of endothelial function, vascular tone and cell stress are altered in altitude illness and may mechanistically contribute to the pathobiology of HAPE.

Resistin Induces Hypertension and Insulin Resistance in Mice via a TLR4-Dependent Pathway

Resistin, an adipokine involved in insulin resistance (IR) and diabetes, has recently been reported to play a role in cardiovascular events. However, its effect on blood pressure (BP) and the underlying mechanisms remain unclear. In the present study, we showed that resistin induces hypertension and IR in wild type (WT) mice, but not in tlr4(-/-) mice. Resistin upregulated angiotensinogen (Agt) expression in WT mice, whereas it had no effect on tlr4(-/-) mice, or in mice treated with the angiotensin-converting enzyme inhibitor perindopril. Real-time PCR and chromatin immunoprecipitation further confirmed that resistin activates the renin-angiotensin system (RAS) via the TLR4/P65/Agt pathway. This finding suggested an essential role of resistin in linking IR and hypertension, which may offer a novel target in clinic on the study of the association between diabetes and hypertension.

Current knowledge on psoriasis and autoimmune diseases

Psoriasis is a prevalent, chronic inflammatory disease of the skin, mediated by crosstalk between epidermal keratinocytes, dermal vascular cells, and immunocytes such as antigen presenting cells (APCs) and T cells. Exclusive cellular “responsibility” for the induction and maintenance of psoriatic plaques has not been clearly defined. Increased proliferation of keratinocytes and endothelial cells in conjunction with APC/T cell/monocyte/macrophage inflammation leads to the distinct epidermal and vascular hyperplasia that is characteristic of lesional psoriatic skin. Despite the identification of numerous susceptibility loci, no single genetic determinant has been identified as responsible for the induction of psoriasis. Thus, numerous other triggers of disease, such as environmental, microbial and complex cellular interactions must also be considered as participants in the development of this multifactorial disease. Recent advances in therapeutics, especially systemic so-called “biologics” have provided new hope for identifying the critical cellular targets that drive psoriasis pathogenesis. Recent recognition of the numerous co-morbidities and other autoimmune disorders associated with psoriasis, including inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus suggest common signaling elements and cellular mediators may direct disease pathogenesis. In this review, we discuss common cellular pathways and participants that mediate psoriasis and other autoimmune disorders that share these cellular signaling pathways.

Differential neutrophil responses to bacterial stimuli: Streptococcal strains are potent inducers of heparin-binding protein and resistin-release

Neutrophils are critical for the control of bacterial infections, but they may also contribute to disease pathology. Here we explore neutrophil responses, in particular the release of sepsis-associated factors heparin-binding protein (HBP) and resistin in relation to specific bacterial stimuli and sepsis of varying aetiology. Analyses of HBP and resistin in plasma of septic patients revealed elevated levels as compared to non-infected critically ill patients. HBP and resistin correlated significantly in septic patients, with the strongest association seen in group A streptococcal (GAS) cases. In vitro stimulation of human neutrophils revealed that fixed streptococcal strains induced significantly higher release of HBP and resistin, as compared to Staphylococcus aureus or Escherichia coli. Similarly, neutrophils stimulated with the streptococcal M1-protein showed a significant increase in co-localization of HBP and resistin positive granules as well as exocytosis of these factors, as compared to LPS. Using a GAS strain deficient in M1-protein expression had negligible effect on neutrophil activation, while a strain deficient in the stand-alone regulator MsmR was significantly less stimulatory as compared to its wild type strain. Taken together, the findings suggest that the streptococcal activation of neutrophils is multifactorial and involves, but is not limited to, proteins encoded by the FCT-locus.

Characteristics of resistin in rheumatoid arthritis angiogenesis

Adipokines have been reported to be involved in the regulation of various physiological processes, including the immune response. Rheumatoid arthritis (RA) is an example of a systemic immune disease that causes chronic inflammation of the synovium and bone destruction in the joint. Recent therapeutic strategies based on the understanding of the role of cytokines and cellular mechanisms in RA have improved our understanding of angiogenesis. On the other hand, endogenous endothelial progenitor cells, which are a population isolated from peripheral blood monocytes have recently been identified as a homing target for pro-angiogeneic factor and vessel formation. In this review, we summarize the effects of common adipokines, such as adiponectin, leptin and resistin in RA pathogenesis and discuss other potential mechanisms of relevance for the therapeutic treatment of RA.

Resistin: New serum marker for predicting severity of acute pancreatitis

OBJECTIVE

To assess the effectiveness of resistin in predicting the severity of acute pancreatitis.

METHODS

Patients with acute pancreatitis who presented at the Gastroenterology Clinic, Erzurum Education and Research Hospital, Turkey were enrolled in this prospective study. White blood cell (WBC), C-reactive protein (CRP) and resistin levels were measured on admission and at 24 h, day 3 and day 7 following admission, along with other blood parameters. Patients were divided into two groups: mild acute pancreatitis and moderate/severe acute pancreatitis.

RESULTS

Of 59 patients with acute pancreatitis (mild, n = 37; moderate/severe, n = 22), significant between-group differences were found in terms of resistin and CRP levels. Receiver operating curve analysis showed that resistin levels were better for predicting severe cases of acute pancreatitis than CRP or WBC levels on day 3 (area under the curve [AUC], 0.88 versus 0.81 and 0.63, respectively). Resistin levels on day 3 were better than CRP levels for predicting necrosis development (AUC, 0.70 versus 0.69, respectively).

CONCLUSIONS

Resistin may represent a new, effective indicator to predict the severity of acute pancreatitis and presence of necrosis in patients with acute pancreatitis.

Quantification and regulation of the adipokines resistin and progranulin in human cerebrospinal fluid

BACKGROUND

Adipokines bearing the potential to cross the blood-brain barrier (BBB) are promising candidates for the endocrine regulation of central nervous processes and of a postulated fat-brain axis. Resistin and progranulin concentrations in paired serum and cerebrospinal fluid (CSF) samples of patients undergoing neurological evaluation and spinal puncture were investigated.

MATERIALS AND METHODS

Samples of n = 270 consecutive patients with various neurological diseases were collected without prior selection. Adipokine serum and CSF concentrations were measured by enzyme-linked immunosorbent assay and serum and CSF routine parameters by standard procedures. Anthropometric data, medication and patient history were available.

RESULTS

Serum levels of resistin and progranulin were positively correlated among each other, with respective CSF levels, low-density lipoprotein cholesterol levels and markers of systemic inflammation. CSF resistin concentrations were generally low. Progranulin CSF concentrations and CSF/serum progranulin ratio were significantly higher in patients with infectious diseases, with disturbed BBB function and with elevated CSF cell count and presence of oligoclonal bands. Both adipokines are able to cross the BBB depending on a differing patency that increases with increasing grade of barrier dysfunction. Whereas resistin represents a systemic marker of inflammation, CSF progranulin levels strongly depend on the underlying disease and dysfunction of blood-CSF barrier.

CONCLUSIONS

Resistin and progranulin represent novel and putative regulators of the fat-brain axis by their ability to cross the BBB under physiological and pathophysiological conditions. The presented data provide insight into the characteristics of BBB function regarding progranulin and resistin and the basis for future establishment of normal values for CSF concentrations and CSF/serum ratios.

Resistin Enhances Inflammatory Cytokine Production in Coronary Artery Tissues by Activating the NF-κB Signaling

Purpose. Kawasaki disease (KD) is a systemic vasculitis and is a leading cause of coronary artery lesions (CALs) in childhood. Our previous study has shown higher levels of serum Resistin in KD patients with coronary aneurysm. This study aimed at examining the association of Resistin with inflammatory cytokine expression in mouse model of coronary arteritis and determining the potential mechanisms. Methods. C57BL/6 mice were injected with Lactobacillus cell wall extract (LCWE) to induce coronary arteritis. The relative levels of Resistin, TNF-α, IL-1β, and MMP-9 expression and inflammatory infiltrates in the coronary arteries were determined longitudinally by quantitative RT-PCR, ELISA, and histology. The effect of TLR4 and NF-κB activation on Resistin-induced TNF-α and IL-1β expression in human coronary artery endothelium cells (HCAECs) was examined by quantitative RT-PCR. Results. Higher levels of Resistin, TNF-α, IL-1β, and MMP-9 expression were associated with the degrees of inflammatory infiltrates in the coronary artery walls of the LCWE-injected mice. Resistin enhanced TNF-α and IL-1β expression in HCAECs at 18 or 24 hours after stimulation. Pretreatment with anti-TLR4 attenuated Resistin-enhanced IL-1β, but not TNF-α, expression and pretreatment with parthenolide or QNZ demolished Resistin-enhanced TNF-α expression in HACECs. Pretreatment with parthenolide, but not QNZ, blocked Resistin-enhanced IL-1β expression in HCAECs. Conclusion. Resistin may enhance inflammation by cross-talking with TLR4/NF-κB signaling during the development of coronary arteritis in mice.

Serum Vaspin Levels Are Associated with the Development of Clinically Manifest Arthritis in Autoantibody-Positive Individuals

Objectives

We have previously shown that overweight may increase the risk of developing rheumatoid arthritis (RA) in autoantibody positive individuals. Adipose tissue could contribute to the development of RA by production of various bioactive peptides. Therefore, we examined levels of adipokines in serum and synovial tissue of subjects at risk of RA.

Methods

Fifty-one individuals positive for immunoglobulin M rheumatoid factor (IgM-RF) and/or anti-citrullinated protein antibodies (ACPA), without arthritis, were included in this prospective study. Levels of adiponectin, vaspin, resistin, leptin, chemerin and omentin were determined in baseline fasting serum samples (n = 27). Synovial tissue was obtained by arthroscopy at baseline and we examined the expression of adiponectin, resistin and visfatin by immunohistochemistry.

Results

The development of clinically manifest arthritis after follow-up was associated with baseline serum vaspin levels (HR1.5 (95% CI 1.1 to 2.2); p = 0.020), also after adjustment for overweight (HR1.7 (95% CI 1.1 to 2.5); p = 0.016). This association was not seen for other adipokines. Various serum adipokine levels correlated with BMI (adiponectin r = -0.538, leptin r = 0.664; chemerin r = 0.529) and systemic markers of inflammation such as CRP levels at baseline (adiponectin r = -0.449, omentin r = -0.557, leptin r = 0.635, chemerin r = 0.619, resistin r = 0.520) and ESR (leptin r = 0.512, chemerin r = 0.708), p-value<0.05. Synovial expression of adiponectin, resistin and visfatin was not associated with development of clinically manifest arthritis.

Conclusions

In this exploratory study, serum adipokines were associated with an increased inflammatory state in autoantibody-positive individuals at risk of developing RA. Furthermore, serum vaspin levels may assist in predicting the development of arthritis in these individuals.

Fucoidan from sea cucumber may improve hepatic inflammatory response and insulin resistance in mice

Nutrition excess-induced inflammation positively contributed to insulin resistance. Fucoidan from sea cucumber can increase glucose translocation in skeletal muscle. However, its effects on inflammation-associated insulin resistance are not understood. We investigated fucoidan from Isostichopus badionotus (Ib-FUC)-alleviated inflammatory response and signaling as well as -improved insulin resistance in the liver of obesity mice. The results showed that Ib-FUC reduced body weight and glucose levels, increased insulin sensitivity, and inhibited serum lipid concentrations. Meanwhile, Hepatic glycogen synthesis was promoted by Ib-FUC via activation of the PI3K/PKB/GSK-3β signaling and regulation of glucose metabolism-related enzymatic activities. Ib-FUC regulated serum inflammatory cytokines and their mRNA expression in the liver. Ib-FUC-induced inactivation of the JNK and IKKβ/NFκB pathways was involved in the activation of insulin signal cascade and inflammatory factor production. These findings suggested that Ib-FUC supplementary-induced alleviation of inflammatory response could be a mechanism responsible for its beneficial effects against hepatic insulin resistance.

Fulvic Acid Attenuates Resistin-Induced Adhesion of HCT-116 Colorectal Cancer Cells to Endothelial Cells

A high level of serum resistin has recently been found in patients with a number of cancers, including colorectal cancer (CRC). Hence, resistin may play a role in CRC development. Fulvic acid (FA), a class of humic substances, possesses pharmacological properties. However, the effect of FA on cancer pathophysiology remains unclear. The aim of this study was to investigate the effect of resistin on the endothelial adhesion of CRC and to determine whether FA elicits an antagonistic mechanism to neutralize this resistin effect. Human HCT-116 (p53-negative) and SW-48 (p53-positive) CRC cells and human umbilical vein endothelial cells (HUVECs) were used in the experiments. Treatment of both HCT-116 and SW-48 cells with resistin increases the adhesion of both cells to HUVECs. This result indicated that p53 may not regulate this resistin effect. A mechanistic study in HCT-116 cells further showed that this resistin effect occurs via the activation of NF-κB and the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Co-treating cells with both FA and resistin revealed that FA significantly attenuated the resistin-increased NF-κB activation and ICAM-1/VCAM-1 expression and the consequent adhesion of HCT-116 cells to HUVECs. These results demonstrate the role of resistin in promoting HCT-116 cell adhesion to HUVECs and indicate that FA might be a potential candidate for the inhibition of the endothelial adhesion of CRC in response to resistin.

Characterization of Visceral and Subcutaneous Adipose Tissue Transcriptome and Biological Pathways in Pregnant and Non-Pregnant Women: Evidence for Pregnancy-Related Regional-Specific Differences in Adipose Tissue

Objective

The purpose of this study was to compare the transcriptome of visceral and subcutaneous adipose tissues between pregnant and non-pregnant women.

Study Design

The transcriptome of paired visceral and abdominal subcutaneous adipose tissues from pregnant women at term and matched non-pregnant women (n = 11) was profiled with the Affymetrix Human Exon 1.0 ST array. Differential expression of selected genes was validated with the use of quantitative reverse transcription–polymerase chain reaction.

Results

Six hundred forty-four transcripts from 633 known genes were differentially expressed (false discovery rate (FDR) <0.1; fold-change >1.5), while 42 exons from 36 genes showed differential usage (difference in FIRMA scores >2 and FDR<0.1) between the visceral and subcutaneous fat of pregnant women. Fifty-six known genes were differentially expressed between pregnant and non-pregnant subcutaneous fat and three genes in the visceral fat. Enriched biological processes in the subcutaneous adipose tissue of pregnant women were mostly related to inflammation.

Conclusion

The transcriptome of visceral and subcutaneous fat depots reveals pregnancy-related gene expression and splicing differences in both visceral and subcutaneous adipose tissue. Furthermore, for the first time, alternative splicing in adipose tissue has been associated with regional differences and human parturition.

Immunological contributions to adipose tissue homeostasis

Adipose tissue is composed of many functionally and developmentally distinct cell types, the metabolic core of which is the adipocyte. The classification of "adipocyte" encompasses three primary types - white, brown, and beige - with distinct origins, anatomic distributions, and homeostatic functions. The ability of adipocytes to store and release lipids, respond to insulin, and perform their endocrine functions (via secretion of adipokines) is heavily influenced by the immune system. Various cell populations of the innate and adaptive arms of the immune system can resist or exacerbate the development of the chronic, low-grade inflammation associated with obesity and metabolic dysfunction. Here, we discuss these interactions, with a focus on their consequences for adipocyte and adipose tissue function in the setting of chronic overnutrition. In addition, we will review the effects of diet composition on adipose tissue inflammation and recent evidence suggesting that diet-driven disruption of the gut microbiota can trigger pathologic inflammation of adipose tissue.

Effect of Weight-Reduction in Obese Mice Lacking Toll-Like Receptor 5 and C57BL/6 Mice Fed a Low-Fat Diet

Background. This study aims to investigate the effect of feeding low-fat diet (LFD) to diet-induced obesity (DIO) mice lacking TLR5 (TLR5^−/−), which have a tendency to develop glucose intolerance with increased adiposity, compared to that in C57BL/6 mice. Results. TLR5^−/− and C57BL/6 male mice were divided into three subgroups: (1) control, mice were fed a standard AIN-76A (fat: 11.5 kcal%) diet for 12 weeks; (2) DIO, mice were fed a 58 kcal% high-fat diet (HFD) for 12 weeks; and (3) diet, mice were fed a HFD for 8 weeks to induce obesity and then switched to a 10.5 kcal% LFD for 4 weeks. The glucose intolerance in DIO TLR5^−/− mice was more significant than that in DIO C57BL/6 mice and was not attenuated by a switch to the LFD. Weight-reduction with LFD had significantly decreased the epididymal fat mass in C57BL/6 mice but not in TLR5^−/− mice. In addition, the LFD-fed TLR5^−/− mice showed significantly higher expression of ghrelin in the serum and resistin in the epididymal fat than that in C57BL/6 mice. Conclusions. This study demonstrated that TLR5 gene knockout impairs some effects of weight-reduction in DIO.

Interactions between adipose tissue and the immune system in health and malnutrition

Adipose tissue provides the body with a storage depot of nutrients that is drained during times of starvation and replenished when food sources are abundant. As such, it is the primary sensor for nutrient availability in the milieu of an organism, which it communicates to the body through the excretion of hormones. Adipose tissue regulates a multitude of body functions associated with metabolism, such as gluconeogenesis, feeding and nutrient uptake. The immune system forms a vital layer of protection against micro-organisms that try to gain access to the nutrients contained in the body. Because infections need to be resolved as quickly as possible, speed is favored over energy-efficiency in an immune response. Especially when immune cells are activated, they switch to fast, but energy-inefficient anaerobic respiration to fulfill their energetic needs. Despite the necessity for an effective immune system, it is not given free rein in its energy expenditure. Signals derived from adipose tissue limit immune cell numbers and activity under conditions of nutrient shortage, whereas they allow proper immune cell activity when food sources are sufficiently available. When excessive fat accumulation occurs, such as in diet-induced obesity, adipose tissue becomes the site of pathological immune cell activation, causing chronic low-grade systemic inflammation. Obesity is therefore associated with a number of disorders in which the immune system plays a central role, such as atherosclerosis and non-alcoholic steatohepatitis. In this review, we will discuss the way in which adipose tissue regulates activity of the immune system under healthy and pathological conditions.

Mouse Resistin (mRetn): cloning, expression and purification in Escherichia coli and the potential regulative effects on murine bone marrow hematopoiesis

Background

Resistin (Retn) is a cytokine which has a controversial physiological role regarding its involvement with obesity and type II diabetes mellitus. Recently, murine Retn was found to be a possibly potential regulator of hematopoiesis in mice shown in the screening results of a set of gene chips which mapped the expression level of murine genes during regeneration of impaired bone marrow (BM) by 5-fluorouracil.

Results

Recombinant mice Retn was expressed in Escherichia coli and purified using ion exchange chromatography. Totally 11.4 mg rmRetn was obtained from 500 ml culture with endotoxin level less than 1.0 EU/ug. The purity of recombinant murine Resistin reached to at least 97.6 % via SDS-PAGE analysis and HPLC. The protein possessed chemotaxis effects in the mouse aortic endothelial cells in vitro in transwell analysis. In vitro, rmRetn could up regulate the CFU number of mice BM and after rmRetn was administered, the cell number of murine bone marrow was significantly increased in vivo after chemotherapy. Finally, rmRetn was found able to protect mice from the chemotoxicity of 5-fluorouracil.

Conclusions

The discovery demonstrated a new function of murine Retn and suggested that it could potentially accelerate bone marrow regeneration post chemotherapy.

Insulin resistance and levels of adipokines in patients with untreated early rheumatoid arthritis

The aim of this study is to investigate the presence of insulin resistance (IR) in patients with untreated early rheumatoid arthritis (ERA) and its relationship with adipokines, inflammatory cytokines, and treatment. In this prospective study, we enrolled 46 ERA patients with a disease duration of <1 year, and 45 sex-, age-, race-, and body mass index (BMI)-matched controls. Patients and controls with diabetes or a history of glucocorticoid (GC) or disease-modifying antirheumatic drugs (DMARDs) use were excluded. Patients were assessed at the time of diagnosis (visit 1) and after 6 months of treatment (visit 2). The main outcomes were homeostatic model assessment of IR (HOMA-IR) and β-cell function (HOMA-β) and quantitative insulin sensitivity check index (QUICKI). A multivariate regression analysis was performed to analyze IR adjusting according to lipids, body composition, physical activity, nutrition, and inflammatory cytokine and adipokine levels. The baseline HOMA-IR, HOMA-β, and QUICKI values were similar in both groups. However, patients showed lower levels of physical activity, total cholesterol, and high-density lipoprotein. Moreover, the inflammatory cytokines and resistin concentrations were higher in patients than controls. Multivariate analysis indicated that BMI and baseline rheumatoid factor levels were positively associated with HOMA-IR and HOMA-β, and negatively with QUICKI. After DMARD treatment, patients showed improvements in inflammatory parameters and lipids whereas IR remained stable. Furthermore, adiponectin and resistin concentrations decreased slightly. Our data suggest that IR is not present in ERA patients either at diagnosis or at 6 months after treatment. However, symptom duration and fat mass appear to be related.

Adipokines and their receptors: potential new targets in cardiovascular diseases

Adipose tissue is an 'endocrine organ' that influences diverse physiological and pathological processes via adipokines secretion. Strong evidences suggest that epicardial and perivascular adipose tissue can directly regulate heart and vessels' structure and function. Indeed, in obesity there is a shift toward the secretion of adipokines that promote a pro-inflammatory status and contribute to obesity cardiomyopathy. The prospect of modulating adipokines and/or their receptors represents an attractive perspective to the treatment of cardiovascular diseases. In this paper, we described the most important actions of certain adipokines and their receptors that are capable of influencing cardiovascular physiology as well as their possible use as therapeutic targets.

Liraglutide treatment causes upregulation of adiponectin and downregulation of resistin in Chinese type 2 diabetes

AIMS

To assess the effect of 16 weeks of liraglutide administration on the plasma levels of adiponectin and resistin in Chinese patients diagnosed with type 2 diabetes mellitus (T2DM).

METHODS

Forty-four subjects were recruited and randomly assigned to once-a-day dosage of either liraglutide, or glimepiride (4 mg) in a double-blinded double-dummy active-controlled study. All treatments were administered in combination with metformin (1 g, twice daily). The efficacy of liraglutide was estimated by measuring and comparing the levels of HbA1c, adiponectin and resistin in the plasma before and after the 16-week treatment.

RESULTS

The plasma level of adiponectin was significantly increased (0.74±0.19 ng/ml, p<0.05) and resistin was significantly lowered (-1.34±0.34 pg/ml, p<0.05) in a dose-dependent manner in the liraglutide group when compared with the glimepiride group (-0.44±0.09 ng/ml of adiponectin and 0.14±0.41 pg/ml of resistin). In contrast, we found no differences in the decrease in HbA1c between the two groups (8.3±1.2% to 7.2±1.1% in NGSP units vs. 8.3±1.0% to 7.3±1.2% in NGSP units; 67±13 mmol/mol to 55±12 mmol/mol vs. 67±11 mmol/mol to 56±13 mmol/mol in IFCC units).

CONCLUSIONS

In Chinese T2DM patients, liraglutide treatment led to increased adiponectin and decreased resistin levels compared to glimepiride-treated subjects, while inducing similar glycemic changes.

In Vitro Fertilization, Levels of Pro-Inflammatory Factors and Lipid Peroxidation

BACKGROUND

Infertility is a problem concerning 10-15% of the individuals in the fertile period. This study investigated effects of proinflammatory factors as well as lipid hydroperoxides (LPO) levels upon in vitro fertilization (IVF) success.

MATERIALS AND METHODS

In this prospective, non-randomized, controlled clinical study, sera obtained from 26 fertile (group-1), 26 infertile women before (group-2) and after (group-3) IVF treatment were analyzed. Leptin, leptin receptor, resistin, tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP) were analyzed using enzyme-linked immunosorbent assay (ELISA). LPO was determined spectrophotometrically. Mann- Whitney U test, paired samples t test, Wilcoxon signed-rank test as well as Pearson correlation analysis by SPSS were performed for statistical analysis.

RESULTS

TNF-α, resistin and LPO levels increased (P=0.020, P=0.003, P=0.001, respectively) in group-3 compared to group-2. A significant increase in LPO was noted both in group-2 and -3 compared to controls (P=0.000). LPO were higher in non-pregnants than pregnants in group-2. For pregnants, significant correlations were observed between leptin and resistin in group-2 and TNF-α and leptin in group-3. None of these correlations were found for the women, who could not conceive.

CONCLUSION

LPO, leptin-resistin correlation, associations with TNF-α may be helpful during the interpretation of IVF success rates.

Possible Involvement of Serum and Synovial Fluid Resistin in Knee Osteoarthritis: Cartilage Damage, Clinical, and Radiological Links

BACKGROUND

Resistin is an adipocytokine associated with inflammation and insulin resistance. Recent studies have shown that resistin plays an important role in the pathogenesis and progression in osteoarthritis (OA) patients. The current study was aimed at investigating the relationship between resistin in serum and synovial fluid (SF) and disease severity in patients with knee osteoarthritis.

METHOD

Seventy-four patients diagnosed with knee OA and 79 healthy controls receiving regular body check in our hospital were recruited in the study. The Noyes score method was used to assess articular cartilage damage arthroscopically. The symptomatic severity was evaluated according to the Western Ontario McMaster University Osteoarthritis (WOMAC) scores. The radiographic disease severity of OA was assessed by the Kellgren-Lawrence (K-L) grading system. The resistin levels in serum and SF were determined by enzyme-linked immunosorbent assay. Cartilage degradation marker CTX-II in SF was also examined.

RESULTS

SF but not serum resistin levels are positively associated with Noyes scores, K-L grading scores WOMAC pain scores, physical functional scores and WOMAC total scores. In addition, SF resistin correlated positively with CTX-II.

CONCLUSION

Resistin in SF might serve as a potential biomarker for reflecting the disease severity and cartilage degenerative extent of knee OA.

Changes in the before and after thyroxine treatment levels of adipose tissue, leptin, and resistin in subclinical hypothyroid patients

BACKGROUND

Subclinical hypothyroidism (SH) occurs when serum thyroid stimulating hormone (TSH) concentrations are raised and serum thyroid hormone concentrations are normal. The effect of SH on the proinflammatory adipose cytokine releasing visceral adipose tissue (VAT) is not clear. The aim of this study is to identify the difference between the pre and posttreatment levels of VAT, leptin, and resistin in SH patients.

METHODS

There were 51 SH patients and 43 age- and gender-matched healthy subjects included in the study. Thyroid functions, biochemical tests, leptin, resistin, and visceral and subcutaneous fat measurements were made. The measurements were repeated in the SH group in the third month following L-thyroxin treatment.

RESULTS

Initially, high sensitivity C-reactive protein, carotid artery intima-media thickness (mm), leptin, and resistin levels were significantly higher in the SH group compared to the controls, while the other parameters were similar. While no correlation was observed between TSH levels and adipokines, a positive correlation was detected between waist circumference and leptin levels (r = 0.549, p < 0.01). Visceral adipose tissue was positively correlated to age, waist circumference, and leptin levels, but negatively correlated to free thyroxin (T4) levels (r = 0.419, p = 0.009; r = 0.794, p < 0.01; r = 0.515, p < 0.01 and r = - 0.416, p = 0.009, respectively). A significant decrease was observed in VAT volume, leptin, and resistin levels of SH patients following levothyroxine treatment. Conclusion The reduced VAT volume, leptin, and resistin levels in SH patients following treatment may support the idea that TSH affects adipose tissue functions.

Evaluation of diagnostic and predictive value of serum adipokines: Leptin, resistin and visfatin in postmenopausal breast cancer

Obesity is a well-known risk factor for cancer. The associations of obesity with postmenopausal breast cancer (PBC) have been previously proven in clinical studies. The mechanisms underlying these associations remain unexplained completely, however, adipose tissue as an endocrine organ producing adipokines may interfere with cancer development. The aim of this study is to investigate the diagnostic and predictive value of serum levels of leptin, resistin and visfatin with inflammatory and tumour markers in relation to anthropometrics, clinicopathological features of PBC. This study included 298 postmenopausal Saudi females categorised into three groups. One hundred and ten BC patients with age matched, 89 healthy control (HC) and 99 females with benign breast lesion (BBL). For all subjects CA15-3, hsCRP, resistin, visfatin and leptin were measured by ELISA. Serum levels of leptin, resistin and visfatin were significantly higher in BC compared to BBL and HC groups (p<0.05). Their levels were also significantly higher in advanced TNM stage, tumour size, LN invasion, histological grade and negative ER or PR cases. The most significant predictor of leptin level was ER (p<0.05). While for resistin and visfatin level the most significant independent predictor was LN invasion. ROC analysis for serum leptin revealed AUC=0.795; 95% CI, 0.724-0.866. Resistin showed AUC=0.875; 95% CI, 0.821-0.928. Meanwhile, visfatin greater than 12.2ng/mL demonstrated a sensitivity and specificity of 97.6% and 92.6%, respectively and AUC=0.724; 95% CI, 0.643-0.804. In conclusion serum leptin, resistin, and visfatin levels could be considered of potential diagnostic value for PBC and they would be independent predictors of LN invasion and ER negative PBC cases.