A family of tissue-specific resistin-like molecules

γδ T cells play a protective role during infection with Nippostrongylus brasiliensis by promoting goblet cell function in the small intestine

The intestinal epithelium is rich in γδ T cells and the gut is a site of residence for a wide variety of pathogens, including nematodes. Although CD4+ T-cell receptor (TCR) -αβ+ T helper type 2 T cells are essential for the expulsion of intestinal nematodes, little information is available on the function of γδ T cells in this type of infection. Here, we demonstrate two major functions of γδ T cells as a potently protective T-cell population against Nippostrongylus brasiliensis infection using γδ T-cell-deficient (TCR-δ(-/-) ) mice. First, γδ T cells are required to initiate rapid expulsion of adult worms from the intestine and to limit egg production. Second, γδ T cells prevent the pathological intestinal damage associated with nematode infection, evident by increased clinical disease and more severe microscopic lesions in infected TCR-δ(-/-) mice. γδ T-cell deficiency led to delayed goblet cell hyperplasia in association with reduced expression of phosphorylated STAT6, MUC2, Trefoil factor-3 (TFF3) and T helper type 2 cytokines including interleukin-13 (IL-13). TCR-δ(-/-) mice also produced more interferon-γ than wild-type mice. Within the intraepithelial lymphocyte compartment, γδ T cells produced IL-13. Adoptive transfer of γδ T cells or administration of recombinant IL-13 to TCR-δ(-/-) mice successfully reduced the egg production by N. brasiliensis. Collectively, these data provide strong evidence that γδ T cells play an important role in controlling infection with intestinal nematodes and limiting infection-induced pathology.

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.

The absence of MyD88 has no effect on the induction of alternatively activated macrophage during Fasciola hepatica infection

Background

Alternatively activated macrophages (AAMϕ) play important roles in allergies and responses to parasitic infections. However, whether signaling through toll-like receptors (TLRs) plays any role in AAMϕ induction when young Fasciola hepatica penetrates the liver capsule and migrates through the liver tissue is still unclear.

Results

The data show that the lack of myeloid differentiation factor 88 (MyD88) has no effect on the AAMϕ derived from the bone marrow (BMMϕ) in vitro and does not impair the mRNA expression of arginase-1, resistin-like molecule (RELMα), and Ym1 in BMMϕs. The Th2 cytokine production bias in splenocytes was not significantly altered in F. hepatica-infected mice in the absence of MyD88 in vitro and in the pleural cavity lavage in vivo. In addition, MyD88-deficiency has no effect on the arginase production of the F. hepatica elicited macrophages (Fe Mϕs), production of RELMα and Ym1 proteins and mRNA expression of Ym1 and RELMα of macrophages in the peritoneal cavity 6 weeks post F. hepatica infection.

Conclusions

The absence of MyD88 has no effect on presence of AAMϕ 6 weeks post F. hepatica infection.

Mouse resistin modulates adipogenesis and glucose uptake in 3T3-L1 preadipocytes through the ROR1 receptor

Mouse resistin, a cysteine-rich protein primarily secreted from mature adipocytes, is involved in insulin resistance and type 2 diabetes. Human resistin, however, is mainly secreted by immune mononuclear cells, and it competes with lipopolysaccharide for the binding to Toll-like receptor 4, which could mediate some of the well-known proinflammatory effects of resistin in humans. In addition, resistin has been involved in the regulation of many cell differentiation and proliferation processes, suggesting that different receptors could be involved in mediating its numerous effects. Thus, a recent work identifies an isoform of Decorin (Δ Decorin) as a functional resistin receptor in adipocyte progenitors that may regulate white adipose tissue expansion. Our work shows that the mouse receptor tyrosine kinase-like orphan receptor (ROR)1 could mediate some of the described functions of resistin in 3T3-L1 adipogenesis and glucose uptake. We have demonstrated an interaction of mouse resistin with specific domains of the extracellular region of the ROR1 receptor. This interaction results in the inhibition of ROR1 phosphorylation, modulates ERK1/2 phosphorylation, and regulates suppressor of cytokine signaling 3, glucose transporter 4, and glucose transporter 1 expression. Moreover, mouse resistin modulates glucose uptake and promotes adipogenesis of 3T3-L1 cells through ROR1. In summary, our results identify mouse resistin as a potential inhibitory ligand for the receptor ROR1 and demonstrate, for the first time, that ROR1 plays an important role in adipogenesis and glucose homeostasis in 3T3-L1 cells. These data open a new line of research that could explain important questions about the resistin mechanism of action in adipogenesis and in the development of insulin resistance.

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.

Vascular biology of metabolic syndrome

The metabolic syndrome is a constellation of clinical risk factors comprising atherogenic dyslipidemia (low high-density lipoprotein and high triglycerides levels), elevated blood pressure, elevated plasma glucose, a prothrombotic state, and a proinflammatory state accompanied by an increased risk for cardiovascular disease and type 2 diabetes mellitus. The adipose tissue of obese humans contains increased numbers of macrophages, and once activated, these macrophages are responsible for the expression of most of the tissue's tumor necrosis factor (TNF)-α and interleukin (IL)-6. Chronic inflammation associated with visceral obesity induces altered lipoprotein metabolism and insulin resistance in the liver. Adipocytes secrete a variety of hormones, cytokines, growth factors, and other bioactive substances, conceptualized as adipocytokines, including plasminogen activator inhibitor 1 (PAI-1), TNF-α, leptin, and adiponectin. The dysregulation of these adipokines contributes to the pathogenesis of obesity. Adipose tissue-resident macrophages and adipocytes in the adipose tissue combined with the consequences of hyperglycemia, altered lipoproteins, and hyperinsulinemia in the vasculature and within organ microcirculation lead to dysfunctional endothelia and a proinflammatory state. Metabolic syndrome thus represents a combination of synergistic vascular pathologies that lead to an accelerated atherogenic state that compromises the ability of the patient to satisfactorily respond to humoral, cellular, and mechanical stresses.

Adipokines and redox signaling: impact on fatty liver disease

Adipokines (adipose tissue cytokines) are polypeptide factors secreted by adipose tissue in a highly regulated manner. The 'classical' adipokines (leptin, adiponectin, and resistin) are expressed only by adipocytes, but other adipokines have been shown to be released by resident and infiltrating macrophages, as well as by components of the vascular stroma. Indeed, adipose tissue inflammation is known to be associated with a modification in the pattern of adipokine secretion. Several studies indicate that adipokines can interfere with hepatic injury associated with fatty infiltration, differentially modulating steatosis, inflammation, and fibrosis. Moreover, plasma levels of adipokines have been investigated in patients with nonalcoholic fatty liver disease in order to establish correlations with the underlying state of insulin resistance and with the type and severity of hepatic damage. In this Forum article, we provide a review of recent data that suggest a significant role for oxidative stress, reactive oxygen species, and redox signaling in mediating actions of adipokines that are relevant in the pathogenesis of nonalcoholic fatty liver disease, including hepatic insulin resistance, inflammation, and fibrosis.

Human resistin: found in translation from mouse to man

The discovery of resistin 10 years ago as a fat cell-secreted factor that modulates insulin resistance suggested a link to the current obesity-associated epidemics of diabetes and cardiovascular disease, which are major human health concerns. Although adipocyte-derived resistin is indisputably linked to insulin resistance in rodent models, the relevance of human resistin is complicated because human resistin is secreted by macrophages rather than adipocytes, and because of the descriptive nature of human epidemiology. In this review, we examine the recent and growing evidence that human resistin is an inflammatory biomarker and a potential mediator of diabetes and cardiovascular disease.

Serum adipokine profiles in Kawasaki disease

Adipokines are cytokines derived from adipose tissue. Recently it has been established that adipokines are closely linked to the pathophysiology of not only metabolic diseases, such as diabetes mellitus, obesity, and atherosclerosis, but also to inflammation and immune diseases. In this study we measured serum levels of adipokines in patients with acute Kawasaki disease to investigate the role of adipokines in the pathophysiology of Kawasaki disease. Serum resistin, high-molecular-weight (HMW) adiponectin, leptin, and visfatin levels were measured by enzyme-linked immunosorbent assay in a total of 117 subjects: 56 patients with acute Kawasaki disease, 30 healthy children, and 31 patients with acute infectious diseases. Serum resistin levels in patients with Kawasaki disease were significantly higher than those of healthy children and patients with acute infectious diseases. In contrast, mean serum HMW adiponectin, leptin, and visfatin levels in patients with Kawasaki disease exhibited no statistically significant differences compared with those in healthy children and patients with infectious diseases. Serum resistin levels decreased significantly after administration of intravenous immune globulin. Serum resistin levels on admission were significantly higher in nonresponders compared with responders to intravenous immune globulin therapy. A multivariate model revealed that C-reactive protein was a factor that was significantly related to elevated serum resistin level in patients with Kawasaki disease. In patients with Kawasaki disease, serum resistin levels were elevated, but decreased to nearly normal after intravenous administration of immune globulin. In contrast, serum HMW adiponectin, leptin, and visfatin levels showed no statistically significant changes. These findings suggest that resistin plays an important role, while other adipokines do not play a major role, in the pathogenesis of Kawasaki disease.

FIZZ2/RELM-β induction and role in pulmonary fibrosis

Found in inflammatory zone (FIZZ) 2, also known as resistin-like molecule (RELM)-β, belongs to a novel cysteine-rich secreted protein family named FIZZ/RELM. Its function is unclear, but a closely related family member, FIZZ1, has profibrotic activities. The human ortholog of rodent FIZZ1 has not been identified, but human FIZZ2 has significant sequence homology to both rodent FIZZ2 (59%) and FIZZ1 (50%). Given the greater homology to rodent FIZZ2, analyzing the role of FIZZ2 in a rodent model of bleomycin-induced pulmonary fibrosis would be of greater potential relevance to human fibrotic lung disease. The results showed that FIZZ2 was highly induced in lungs of rodents with bleomycin-induced pulmonary fibrosis and of human patients with idiopathic pulmonary fibrosis. FIZZ2 expression was induced in rodent and human lung epithelial cells by Th2 cytokines, which was mediated via STAT6 signaling. The FIZZ2 induction in murine lungs was found to be essential for pulmonary fibrosis, as FIZZ2 deficiency significantly suppressed pulmonary fibrosis and associated enhanced extracellular matrix and cytokine gene expression. In vitro analysis indicated that FIZZ2 could stimulate type I collagen and α-smooth muscle actin expression in lung fibroblasts. Furthermore, FIZZ2 was shown to have chemoattractant activity for bone marrow (BM) cells, especially BM-derived CD11c(+) dendritic cells. Notably, lung recruitment of BM-derived cells was impaired in FIZZ2 knockout mice. These findings suggest that FIZZ2 is a Th2-associated multifunctional mediator with potentially important roles in the pathogenesis of fibrotic lung diseases.

The implication of adiponectin and resistin in gastrointestinal diseases

Adiponectin and resistin, members of the adipokine family, are multi-task hormones involved in several disorders, including those of the alimentary tract. In the present review, eligible studies focusing on the role of adiponectin and resistin in gastrointestinal diseases are manifested together and classified according to anatomic criteria. In addition, similarities and common patterns have been recognized, ultimately revealing an inverse association: the down-regulation of adiponectin and up-regulation of resistin - both in vitro and in vivo - in gastrointestinal disorders, irrespective of their diverse nature - inflammatory, autoimmune or malignant - or anatomic position - esophageal, gastric, of the small intestine, colonic. Finally, a potential role for both adipokines in alimentary tract-related carcinogenesis has been identified, possibly representing a missing link between obesity and cancer.

Elevated resistin opposed to adiponectin or angiogenin plasma levels as a strong, independent predictive factor for the occurrence of major adverse cardiac and cerebrovascular events in patients with stable multivessel coronary artery disease over 1-year follow-up

Background

Adipokines such as adiponectin and resistin, as well as angiogenin, may be associated with inflammation and atherosclerosis. The relationship between their levels and prognosis in high risk patients is, however, still unclear. The aim of this study was to evaluate the prognostic value of these adipokines in patients with stable multivessel coronary artery disease (MCAD).

Material/Methods

The study group comprised 107 MCAD patients (74% males, mean age 63±8 years). Adiponectin, resistin and angiogenin plasma levels were measured at admission and after 1-year follow-up. Primary end point (major adverse cardiac and cerebrovascular events – MACCE) was defined as cardiac death, nonfatal myocardial infarction, stroke, and hospitalization for angina or heart failure over a 1-year period.

Results

After 1-year follow-up, 9 (8%) patients died, all from cardiovascular causes. Primary end point was experienced by 32% of patients. Surgical treatment (CABG) was received by 51% of patients, while 49% were treated medically alone. Total cholesterol concentration levels ≥173 mg/dl were associated with a 7-fold increase (OR 7.3; 95% CI, 1.6–33.0); LDL ≥93.5 mg/dl with a 16-fold increase (OR 16.3; 95% CI, 2.8–93.8), and resistin ≥17.265 ng/ml with a 13-fold increase in MACCE risk (OR 13.5; 95% CI, 2.3–80.3). In multivariate analysis, a medical treatment strategy (p=0.001), a higher CCS class (p=0.004), resistin levels (p=0.003) and a higher Gensini score (p=0.03) were independent predictors of MACCE.

Conclusions

In stable patients with MCAD, elevated plasma resistin (as opposed to adiponectin or angiogenin) is a strong, independent predictive factor for the occurrence of MACCE over 1-year follow-up.

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.

The crosstalks between adipokines and catecholamines

Adipocytes, which secrete a spectrum of adipokines, play an integral role in metabolism via communications with other endocrine cells. In the present work, we have studied the interplays between adipokines and catecholamines, using 3T3-L1 adipocytes and PC12 cells as the cell models and an integrative experimental platform. We demonstrate that all catecholamines inhibit vesicle trafficking and secretion of leptin and resistin through β-adrenergic receptors, while leptin and resistin enhance the vesicle trafficking and secretion of catecholamines through PKC, PKA, MAPK kinase and Ca(2+) dependent pathways. The crosstalks between adipokines and catecholamines were further corroborated by co-culturing 3T3-L1 adipocytes and PC12 cells. Our findings highlight the importance of adipo-adrenal axis in energy metabolism and the intricate interactions between metabolic hormones.

Expression and effect of resistin on bovine and rat granulosa cell steroidogenesis and proliferation

Resistin, initially identified in adipose tissue and macrophages, was implicated in insulin resistance. Recently, its mRNA was found in hypothalamo-pituitary axis and rat testis, leading us to hypothesize that resistin may be expressed in ovary. In this study, we determined in rats and cows 1) the characterization of resistin in ovary by RT-PCR, immunoblotting, and immunohistochemistry and 2) the effects of recombinant resistin (10, 100, 333, and 667 ng/ml) ± IGF1 (76 ng/ml) on steroidogenesis, proliferation, and signaling pathways of granulosa cells (GC) measured by enzyme immunoassay, [(3)H]thymidine incorporation, and immunoblotting respectively. We observed that resistin mRNA and protein were present in several bovine and rat ovarian cells. Nevertheless, only bovine GC abundantly expressed resistin mRNA and protein. Resistin treatment decreased basal but not IGF1-induced progesterone (P<0.05; whatever the dose) and estradiol (P<0.005; for 10 and 333 ng/ml) production by bovine GC. In rats, resistin (10 ng/ml) increased basal and IGF1-induced progesterone secretion (P<0.0001), without effect on estradiol release. We found no effect of resistin on rat GC proliferation. Conversely, in cows, resistin increased basal proliferation (P<0.0001; for 100-667 ng/ml) and decreased IGF1-induced proliferation of GC (P<0.0001; for 10-333 ng/ml) associated with a decrease in cyclin D2 protein level (P<0.0001). Finally, resistin stimulated AKT and p38-MAPK phosphorylation in both species, ERK1/2-MAPK phosphorylation in rats and had the opposite effect on the AMPK pathway (P<0.05). In conclusion, our results show that resistin is expressed in rat and bovine ovaries. Furthermore, it can modulate GC functions in basal state or in response to IGF1 in vitro.

Association of adiponectin, resistin, and vascular inflammation: analysis with 18F-fluorodeoxyglucose positron emission tomography

OBJECTIVE

Adiponectin and resistin are adipokines that are linked to obesity, inflammation, and atherosclerosis. (18)F-Fluorodeoxyglucose (FDG) positron emission tomography is a promising imaging technique that can be used to evaluate vascular inflammation.

METHODS AND RESULTS

We measured adiponectin and resistin levels, as well as traditional cardiovascular risk factors, in 60 obese subjects and 60 nonobese controls. In addition, we compared carotid intima-media thickness and target-to-background ratio (TBR) measured using (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography. The mean TBR values were significantly higher in the obese group compared with normal subjects, although their mean carotid intima-media thickness levels were not significantly different. Serum adiponectin levels showed a significant negative correlation with mean TBR values (r = -0.215, P = 0.020), whereas resistin levels were positively correlated with mean TBR values (r = 0.214, P = 0.021). Multiple linear regression analysis showed that mean TBR values were independently associated with body mass index, high-sensitivity C-reactive protein, and resistin levels (R(2) = 0.308).

CONCLUSIONS

Adiponectin and resistin may be useful as biomarkers to reflect vascular inflammation. In particular, resistin levels were independently associated with vascular inflammation even after adjusting for other cardiovascular risk factors.

The serum levels of resistin in ankylosing spondylitis patients: a pilot study

Resistin is a recently described adipokine which is a member of cysteine-rich secretory protein family. Although it has been primarily defined in human adipocytes, it has been identified that its level was higher in mononuclear leukocytes, macrophages, spleen, and bone marrow cells. Because ankylosing spondylitis is an inflammatory disease, it is suspected that upregulation of proinflammatory cytokines is effective in its immunopathogenesis. The aim of our study is to determine the serum resistin levels in patients with AS and to research the relationship with disease activity markers. A total of 30 patients with AS and 30 healthy controls were included in this study. Serum resistin concentrations, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Bath AS Disease Activity Index (BASDAI) were evaluated. In results resistin levels in ankylosing spondylitis group were significantly higher than in control group. But, there was no correlation between resistin and ESR, CRP, BASDAI. In conclusion, higher serum resistin levels in patients with AS compared to healthy subjects give clues that resistin could have a role in the pathogenesis of AS.

S100A11 mediates hypoxia-induced mitogenic factor (HIMF)-induced smooth muscle cell migration, vesicular exocytosis, and nuclear activation

Hypoxia-induced mitogenic factor (HIMF) is a newly discovered protein that is up-regulated in murine models of pulmonary arterial hypertension and asthma. Our previous study shows that HIMF is a potent mitogenic, angiogenic, and vasoconstrictive chemokine associated with pulmonary arterial hypertension. Two-dimensional gel electrophoresis was used to investigate downstream molecules in HIMF-induced cell signaling, demonstrating that S100A11, an EF-hand calcium-binding protein, was exclusively altered and was decreased (2.7±0.2-fold, p<0.05) in pulmonary artery smooth muscle cells (SMCs) treated with HIMF for 5 min compared with untreated cells (n=4). Immunofluorescence showed that in control cells S100A11 is a cytosolic protein, which then aggregates and translocates both to the plasma membrane with subsequent exocytosis and to the nucleus upon HIMF stimulation. Annexin A2, a known S100A11 binding partner, also colocalized with S100A11 during HIMF-induced membrane trafficking. To investigate the intracellular function of S100A11, siRNA was used to knock down S100A11 expression in SMCs. The S100A11 knockdown significantly reduced HIMF-induced SMC migration but did not affect the SMC mitogenic action of HIMF. Our data show that S100A11 mediates HIMF-induced smooth muscle cell migration, vesicular exocytosis, and nuclear activation.

Plasma levels of resistin-like molecule beta in humans

BACKGROUND

Resistin-like molecules (RELM) are expressed in many tissues and among those, RELMβ is most abundantly expressed in the colon. Based on animal studies, RELMβ is induced by high fat diets, obesity, and intestinal microflora and may play a role in insulin resistance and intestinal inflammation. In the present study, we evaluated whether RELMβ could be measured in human plasma and the influence of selected host and behavioral factors on RELMβ levels, including known risk factors for colorectal cancer.

METHODS

The subjects for this pilot study were derived from healthy controls who participated in a population-based case-control study of colorectal cancer in Metropolitan Detroit. The subjects were 45-80 years of age without history of cancer or colorectal resection.

RESULTS

RELMβ was present in human plasma, with levels in the range of 0.08-0.26 ng/mL. Lower RELMβ levels were found in subjects with non-Caucasian race, lower pack-years of smoking, and higher physical activity index scores. Other variables such as dietary intakes, gender, obesity, use of non-steroidal anti-inflammatory agents and history of polyps were not associated with RELMβ levels.

CONCLUSIONS

The direct association of RELMβ with smoking and inverse association with physical activity, both of which are risk factors for colon cancer, indicates that RELMβ may be involved in mediating the effects of these two lifestyle factors on risk of colon cancer.

Resistin is associated with mortality in patients with traumatic brain injury

INTRODUCTION

Recently, we reported that high levels of resistin are present in the peripheral blood of patients with intracerebral hemorrhage and are associated with a poor outcome. However, not much is known regarding the change in plasma resistin and its relation with mortality after traumatic brain injury (TBI). Thus, we sought to investigate change in plasma resistin level after TBI and to evaluate its relation with disease outcome.

METHODS

Fifty healthy controls and 94 patients with acute severe TBI were included. Plasma samples were obtained on admission and at days 1, 2, 3, 5 and 7 after TBI. Its concentration was measured by enzyme-linked immunosorbent assay.

RESULTS

Twenty-six patients (27.7%) died from TBI within 1 month. After TBI, plasma resistin level in patients increased during the 6-hour period immediately after TBI, peaked within 24 hours, plateaued at day 2, decreased gradually thereafter and was substantially higher than that in healthy controls during the 7-day period. A forward stepwise logistic regression selected plasma resistin level (odds ratio, 1.107; 95% confidence interval, 1.014-1.208; P = 0.023) as an independent predictor for 1-month mortality of patients. A multivariate linear regression showed that plasma resistin level was negatively associated with Glasgow Coma Scale score (t = -6.567, P < 0.001). A receiver operating characteristic curve identified plasma resistin cutoff level (30.8 ng/mL) that predicted 1-month mortality with the optimal sensitivity (84.6%) and specificity (75.0%) values (area under curve, 0.854; 95% confidence interval, 0.766-0.918; P < 0.001).

CONCLUSIONS

Increased plasma resistin level is found and associated with Glasgow Coma Scale score and mortality after TBI.

New approach in the interpretation of the adipose tissue

Az elmúlt másfél évtized kutatásai bebizonyították, hogy a zsírszövet aktív endokrin szerv, amely számos hormont választ el. A szerzők a leptin, az adiponektin, a rezisztin, a visfatin és az omentin hormonok működését mutatják be, különös tekintettel az anyagcsere-folyamatokra gyakorolt hatásukra.

Regulation of gene expression by FSP27 in white and brown adipose tissue

BACKGROUND

Brown and white adipose tissues (BAT and WAT) play critical roles in controlling energy homeostasis and in the development of obesity and diabetes. The mouse Fat-Specific protein 27 (FSP27), a member of the cell death-inducing DFF45-like effector (CIDE) family, is expressed in both BAT and WAT and is associated with lipid droplets. Over-expression of FSP27 promotes lipid storage, whereas FSP27 deficient mice have improved insulin sensitivity and are resistant to diet-induced obesity. In addition, FSP27-deficient white adipocytes have reduced lipid storage, smaller lipid droplets, increased mitochondrial activity and a higher expression of several BAT-selective genes. To elucidate the molecular mechanism by which FSP27 controls lipid storage and gene expression in WAT and BAT, we systematically analyzed the gene expression profile of FSP27-deficient WAT by microarray analysis and compared the expression levels of a specific set of genes in WAT and BAT by semi-quantitative real-time PCR analysis.

RESULTS

BAT-selective genes were significantly up-regulated, whereas WAT-selective genes were down-regulated in the WAT of FSP27-deficient mice. The expression of the BAT-selective genes was also dramatically up-regulated in the WAT of leptin/FSP27 double deficient mice. In addition, the expression levels of genes involved in multiple metabolic pathways, including oxidative phosphorylation, the TCA cycle, fatty acid synthesis and fatty acid oxidation, were increased in the FSP27-deficient WAT. In contrast, the expression levels for genes involved in extracellular matrix remodeling, the classic complement pathway and TGF-beta signaling were down-regulated in the FSP27-deficient WAT. Most importantly, the expression levels of regulatory factors that determine BAT identity, such as CEBP alpha/beta, PRDM16 and major components of the cAMP pathway, were markedly up-regulated in the WAT of FSP27-deficient mice. The expression levels of these regulatory factors were also up-regulated in leptin/FSP27 double deficient mice. Interestingly, distinct gene expression profiles were observed in the BAT of FSP27-deficient mice. Taken together, these data suggest that the WAT of FSP27-deficient mice have a gene expression profile similar to that of BAT.

CONCLUSIONS

FSP27 acts as a molecular determinant that controls gene expression for a diversity of metabolic and signaling pathways and, in particular, the expression of regulatory factors, including CEBP alpha/beta, PRDM16 and components of the cAMP signaling pathway, that control the identity of WAT and BAT.

Momordica charantia (bitter melon) inhibits primary human adipocyte differentiation by modulating adipogenic genes

BACKGROUND

Escalating trends of obesity and associated type 2 diabetes (T2D) has prompted an increase in the use of alternative and complementary functional foods. Momordica charantia or bitter melon (BM) that is traditionally used to treat diabetes and complications has been demonstrated to alleviate hyperglycemia as well as reduce adiposity in rodents. However, its effects on human adipocytes remain unknown. The objective of our study was to investigate the effects of BM juice (BMJ) on lipid accumulation and adipocyte differentiation transcription factors in primary human differentiating preadipocytes and adipocytes.

METHODS

Commercially available cryopreserved primary human preadipocytes were treated with and without BMJ during and after differentiation. Cytotoxicity, lipid accumulation, and adipogenic genes mRNA expression was measured by commercial enzymatic assay kits and semi-quantitative RT-PCR (RT-PCR).

RESULTS

Preadipocytes treated with varying concentrations of BMJ during differentiation demonstrated significant reduction in lipid content with a concomitant reduction in mRNA expression of adipocyte transcription factors such as, peroxisome proliferator-associated receptor gamma (PPARgamma) and sterol regulatory element-binding protein 1c (SREBP-1c) and adipocytokine, resistin. Similarly, adipocytes treated with BMJ for 48 h demonstrated reduced lipid content, perilipin mRNA expression, and increased lipolysis as measured by the release of glycerol.

CONCLUSION

Our data suggests that BMJ is a potent inhibitor of lipogenesis and stimulator of lipolysis activity in human adipocytes. BMJ may therefore prove to be an effective complementary or alternative therapy to reduce adipogenesis in humans.

Adipocytokines in atherothrombosis: focus on platelets and vascular smooth muscle cells

Visceral obesity is a relevant pathological condition closely associated with high risk of atherosclerotic vascular disease including myocardial infarction and stroke. The increased vascular risk is related also to peculiar dysfunction in the endocrine activity of adipose tissue responsible of vascular impairment (including endothelial dysfunction), prothrombotic tendency, and low-grade chronic inflammation. In particular, increased synthesis and release of different cytokines, including interleukins and tumor necrosis factor-α (TNF-α), and adipokines—such as leptin—have been reported as associated with future cardiovascular events. Since vascular cell dysfunction plays a major role in the atherothrombotic complications in central obesity, this paper aims at focusing, in particular, on the relationship between platelets and vascular smooth muscle cells, and the impaired secretory pattern of adipose tissue.

Hypoxia-induced mitogenic factor (HIMF/FIZZ1/RELM alpha) recruits bone marrow-derived cells to the murine pulmonary vasculature

BACKGROUND

Pulmonary hypertension (PH) is a disease of multiple etiologies with several common pathological features, including inflammation and pulmonary vascular remodeling. Recent evidence has suggested a potential role for the recruitment of bone marrow-derived (BMD) progenitor cells to this remodeling process. We recently demonstrated that hypoxia-induced mitogenic factor (HIMF/FIZZ1/RELM alpha) is chemotactic to murine bone marrow cells in vitro and involved in pulmonary vascular remodeling in vivo.

METHODOLOGY/PRINCIPAL FINDINGS

We used a mouse bone marrow transplant model in which lethally irradiated mice were rescued with bone marrow transplanted from green fluorescent protein (GFP)(+) transgenic mice to determine the role of HIMF in recruiting BMD cells to the lung vasculature during PH development. Exposure to chronic hypoxia and pulmonary gene transfer of HIMF were used to induce PH. Both models resulted in markedly increased numbers of BMD cells in and around the pulmonary vasculature; in several neomuscularized small (approximately 20 microm) capillary-like vessels, an entirely new medial wall was made up of these cells. We found these GFP(+) BMD cells to be positive for stem cell antigen-1 and c-kit, but negative for CD31 and CD34. Several of the GFP(+) cells that localized to the pulmonary vasculature were alpha-smooth muscle actin(+) and localized to the media layer of the vessels. This finding suggests that these cells are of mesenchymal origin and differentiate toward myofibroblast and vascular smooth muscle. Structural location in the media of small vessels suggests a functional role in the lung vasculature. To examine a potential mechanism for HIMF-dependent recruitment of mesenchymal stem cells to the pulmonary vasculature, we performed a cell migration assay using cultured human mesenchymal stem cells (HMSCs). The addition of recombinant HIMF induced migration of HMSCs in a phosphoinosotide-3-kinase-dependent manner.

CONCLUSIONS/SIGNIFICANCE

These results demonstrate HIMF-dependent recruitment of BMD mesenchymal-like cells to the remodeling pulmonary vasculature.

The emerging role of adipokines in osteoarthritis: a narrative review

Osteoarthritis (OA) is a most common multifactorial degenerative joint disease in elderly individuals. OA is affecting severely the quality of life of patients, while the causes of OA are not completely understood. Age, obesity, the female sex, and previous injury are considered as significant risk factors. Recently, increased levels of adipokines which are mainly produced by adipocytes have been detected in patients with osteoarthritis. Moreover, studies on different adipokines all reveal that they have played proinflammatory and catabolic/anabolic roles during the pathophysiology of OA. In the present review, we summarize current data on the effect of the adipose tissue-derived hormones leptin, adiponectin, resistin and visfatin on initiation and progression of OA.

Effect of conjugated linoleic acid on body fat, tumor necrosis factor alpha and resistin secretion in spontaneously hypertensive rats

Conjugated linoleic acid (CLA) is a naturally occurring group of dienoic derivaties of linoleic acid found mainly in beef and dairy products. CLA has been reported to reduce body fat, as well as to possess anticarcinogenic, antiatherogenic and procatabolic activities in animals. The objective of this study was to evaluate the effect of CLA supplementation to spontaneously hypertensive rats (SHR) on body fat, biochemical parameters of serum related tumor necrosis factor alpha (TNF-alpha) and resistin secretion. Thirty rats were divided in three groups, the first group of spontaneously hypertensive rats received a standard diet (V-SHR group, n=10), a second group of SHR was fed 1.5% of conjugated linoleic acid (CLA-SHR group, n=10) and the third was the control, non-hypertensive group (KW, n=10) also on a standard diet including 7.5% of sunflower oil during eight weeks. After CLA diet administration, spontaneously hypertensive rats showed a significant reduction in blood pressure, serum glucose, cholesterol and triacylglycerols, together with reduction of index of body fat, pericardic, abdominal and epididymal adipose tissue. These effects were accompanied by a decrease in the secretion of TNF-alpha and resistin.

Similarity and diversity in macrophage activation by nematodes, trematodes, and cestodes

This review summarizes current knowledge of macrophages in helminth infections, with a focus not only on delineating the striking similarities in macrophage phenotype between diverse infections but also on highlighting the differences. Findings from many different labs illustrate that macrophages in helminth infection can act as anti-parasite effectors but can also act as powerful immune suppressors. The specific role for their alternative (Th2-mediated) activation in helminth killing or expulsion versus immune regulation remains to be determined. Meanwhile, the rapid growth in knowledge of alternatively activated macrophages will require an even more expansive view of their potential functions to include repair of host tissue and regulation of host metabolism.

Expression of resistin-like molecule beta in Barrett's esophagus: a novel biomarker for metaplastic epithelium

The formation of goblet cells characterizes the intestinal metaplasia of Barrett's esophagus (BE). Hematoxylin-eosin (HE) staining may fail to show intestinal metaplasia in BE, and PAS-Alcian Blue may present difficulties of interpretation due to its more heterogeneous staining. Recent evidence indicates that expression of resistin-like molecule beta (RELMbeta), a goblet cell-specific protein, is uniquely restricted to intestinal epithelium. However, it still remains largely unknown whether RELMbeta can be served as a biomarker for metaplastic epithelium of BE. In this study, 104 biopsy specimens of the distal esophagus from 88 suspected BE patients were collected, including 56 suspected intestinal metaplasia, 26 gastric type mucosa, and 22 squamous epithelium. We evaluated the RELMbeta expression in these biopsy specimens, and compared with those of CDX-2 immunostaining and PAS-Alcian Blue staining (pH 2.5). Of the suspected intestinal metaplasia specimens, 46 presented intestinal-type goblet cells and were immunostaining positive for RELMbeta and CDX-2, the remaining ten possessed only goblet cell mimickers and were not reactive with RELMbeta and CDX-2. Of the gastric-type mucosa specimens, none reacted with either RELMbeta or CDX-2. Moreover, the squamous epithelium was not reactive with RELMbeta and CDX-2. Acid mucin was present in goblet cells in all cases of BE and columnar cells in ten gastric specimens. In addition, the reactivity of RELMbeta was enhanced in six BE specimens with dysplasia. These results provide evidence that RELMbeta protein may be a novel biomarker to distinguish the intestinal-type goblet cells and goblet cell mimickers, and useful in the correct diagnosis of BE.

Expression of resistin-like molecule beta in gastric cancer: its relationship with clinicopathological parameters and prognosis

Resistin-like molecule beta (RELMbeta), an intestinal goblet cell-specific protein, is a biomarker of intestinal metaplasia in Barrett's esophagus and over-expressed in colon cancer. Since gastric adenocarcinomas can arise through a process of intestinalization, we hypothesized that RELMbeta might be aberrantly expressed in gastric cancer. This study was undertaken to examine the RELMbeta expression in gastric cancer and correlate it with clinical outcome. One hundred and thirty-six gastric cancer patients were evaluated for the RELMbeta expression by immunohistochemistry. The RELMbeta transcripts were measured by real-time quantitative PCR. In normal gastric mucosa, RELMbeta expression was absent, whereas areas of intestinal metaplasia revealed RELMbeta reactivity. Eighty-nine patients of gastric cancer (65.4%) were positive for RELMbeta expression. In a subtotal of 20 patients, RELMbeta transcripts were positively correlated with protein levels in gastric cancer tissues, but absent in normal gastric mucosa. The expression rate of RELMbeta was higher in intestinal-type carcinomas than in diffuse-type carcinomas (P < 0.001). RELMbeta positivity in gastric cancer was positively correlated with tumor differentiation (P = 0.001) and inversely correlated with tumor infiltration (P = 0.007), lymph node metastasis (P = 0.035), and heparanase expression (P < 0.001), without correlation with age, gender, tumor location and size, tumor-node metastasis stages, and Ki-67 expression. Patients showing positive RELMbeta expression had a significantly longer overall survival than those with negative expression (P = 0.001). These results provide evidences that the RELMbeta expression in gastric cancer is correlated with clinicopathological features and may be a useful prognostic factor for predicting the outcome of gastric cancer patients.

Serum levels of resistin and hsCRP in women with PCOS

Resistin has been associated with obesity and type 2 diabetes. The elevated serum resistin level in human diabetes is often associated with a pro-inflammatory milieu. In vitro data suggest that C-reactive protein (CRP) significantly increases resistin expression in cultured human PBMC, yet the relationship in vivo is largely unknown. The purpose of this study was to determine the concentrations of CRP and resistin in women with polycystic ovary syndrome (PCOS) and to clarify whether or not there are correlations between CRP and resistin levels that have not previously been studied in PCOS in the context of resistin. Serum resistin and hsCRP levels of forty-five women with PCOS were analyzed. Compared with the control group, women with PCOS had significantly higher serum concentrations of resistin (p=0.009). Women with PCOS had higher hsCRP levels compared with controls, but these differences were not statistically significant (p>0.05). There was no correlation between serum resistin and hsCRP levels (r=0.128, p=0.404). Our study suggests that resistin concentrations was not associated with hsCRP levels

Oxidative stress and asthma: proteome analysis of chitinase-like proteins and FIZZ1 in lung tissue and bronchoalveolar lavage fluid

Oxidative stress plays an important role in the development of airway inflammation and hyperreactivity in asthma. The identification of oxidative stress markers in bronchoalveolar lavage fluid (BALF) and lung tissue from ovalbumin (OVA) sensitized mice could provide new insight into disease pathogenesis and possible use of antioxidants to alleviate disease severity. We used two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the impact of the thiol antioxidant, N-acetylcysteine (NAC), on protein expression in a murine OVA model. At least six proteins or protein families were found to be significantly increased in BALF from OVA-challenged mice compared to a control group: Chitinase 3-like protein 3 (Yml), Chitinase 3-like protein 4 (Ym2), acidic mammalian Chitinase (AMCase), pulmonary surfactant-associated protein D (SP-D), resistin-like molecule alpha (RELMalpha) or "found in inflammatory 1" (FIZZ1), and haptoglobin alpha-subunit. A total of nine proteins were significantly increased in lung tissue from the murine asthma model, including Yml, Ym2, FIZZ1, and other lung remodeling-related proteins. Western blotting confirmed increased Yml/Ym2, SP-D, and FIZZ1 expression measured from BAL fluid and lung tissue from OVA-challenged mice. Intraperitoneal NAC administration prior to the final OVA challenge inhibited Yml/Ym2, SP-D, and FIZZ1 expression in BALF and lung tissue. The oxidative stress proteins, Ym1/Ym2, FIZZ1, and SP-D, could play an important role in the pathogenesis of asthma and may be useful oxidative stress markers.

SAM pointed domain ETS factor (SPDEF) regulates terminal differentiation and maturation of intestinal goblet cells

BACKGROUND AND AIMS

SPDEF (also termed PDEF or PSE) is an ETS family transcription factor that regulates gene expression in the prostate and goblet cell hyperplasia in the lung. Spdef has been reported to be expressed in the intestine. In this paper, we identify an important role for Spdef in regulating intestinal epithelial cell homeostasis and differentiation.

METHODS

SPDEF expression was inhibited in colon cancer cells to determine its ability to control goblet cell gene activation. The effects of transgenic expression of Spdef on intestinal differentiation and homeostasis were determined.

RESULTS

In LS174T colon cancer cells treated with Notch/gamma-secretase inhibitor to activate goblet cell gene expression, shRNAs that inhibited SPDEF also repressed expression of goblet cell genes AGR2, MUC2, RETLNB, and SPINK4. Transgenic expression of Spdef caused the expansion of intestinal goblet cells and corresponding reduction in Paneth, enteroendocrine, and absorptive enterocytes. Spdef inhibited proliferation of intestinal crypt cells without induction of apoptosis. Prolonged expression of the Spdef transgene caused a progressive reduction in the number of crypts that expressed Spdef, consistent with its inhibitory effects on cell proliferation.

CONCLUSIONS

Spdef was sufficient to inhibit proliferation of intestinal progenitors and induce differentiation into goblet cells; SPDEF was required for activation of goblet cell associated genes in vitro. These data support a model in which Spdef promotes terminal differentiation into goblet cells of a common goblet/Paneth progenitor.

Resistin is stored in neutrophil granules being released upon challenge with inflammatory stimuli

We have recently shown that resistin is a key mediator of arthritis accumulating in the inflamed joints and exerting its pro-inflammatory properties independently of TNFalpha. Here we evaluate neutrophils as a cellular source of resistin. Human neutrophils were subjected to subcellular fractionation where the presence of resistin was assessed using western blot, ELISA, and mass spectrometry. Presence of resistin on the neutrophil surface was visualized by flow cytometry. More than 95% of the neutrophils in circulation and in synovial fluid express resistin on their surface. Stimulation of mature neutrophils with fMLF induced release of resistin into supernatants and increased expression of resistin on the surface. Resistin is mobilized simultaneously with lactoferrin, a protein found in specific granules, and with granule-stored CR3/CD11b. Subcellular fractionation of human neutrophils demonstrated the presence of resistin in azurophilic and in specific granules. Here we show that neutrophils have two pools of resistin, the major one exists in specific granules, and the second on their cell membrane. Release of resistin from the neutrophil granules probably serves the main source of resistin at the site of inflammation.

Resistin competes with lipopolysaccharide for binding to toll-like receptor 4

Toll-like receptors (TLRs) are a family of cellular structures activated by recognition of pathogen associated molecular sequences. The activation of TLRs triggers a variety of intracellular mechanisms aiming to protect the host from the invading microorganisms. Lipopolysaccharide (LPS) is the main ligand for TLR4. Here we show that resistin, a cystein-rich protein believed to regulate carbohydrate metabolism, competes with LPS for binding to TLR4. Binding of recombinant resistin to human myeloid and epithelial cells was assessed by flow cytometry and its co-precipitation with TLR4 was demonstrated. Antibodies against TLR4 abolished resistin binding to human leucocytes and cytokine production by peripheral blood mononuclear cells in response to resistin stimulation. In contrast, isotype-matched murine IgG or TLR2 antibodies were unable to prevent binding of resistin to the cells. Similarly, TLR4-dependent pattern of resistin binding was observed in epithelial cell line HEK293 (human epithelial kidney cell), where TLR4 transfected, but not myeloid differentiation factor 2/CD14-transfected, TLR2 transfected or HEKnull cells, responded functionally to resistin stimulation. Intracellular signalling of resistin was assessed using inhibitors of transcription factors mitogen activated protein kinases, nuclear factor-kappaB, phosphoinositide 3-kinase and siRNA targeting TLR4 and human myeloid differentiation factor 88. Results demonstrate that TLR4 serves as a receptor for the pro-inflammatory effects of resistin in human cells. This may partly explain the multifunctional role of resistin in chronic inflammation, atherosclerosis and insulin resistance.

The role of resistin as a regulator of inflammation: Implications for various human pathologies

Resistin was originally described as an adipocyte-secreted peptide that induced insulin resistance in rodents. Increasing evidence indicates its important regulatory roles in various biological processes, including several inflammatory diseases. Further studies have shown that resistin in humans, in contrast to its production by adipocytes in mice, is synthesized predominantly by mononuclear cells both within and outside adipose tissue. Possible roles for resistin in obesity-related subclinical inflammation, atherosclerosis and cardiovascular disease, non-alcoholic fatty liver disease, rheumatic diseases, malignant tumors, asthma, inflammatory bowel disease, and chronic kidney disease have already been demonstrated. In addition, resistin can modulate several molecular pathways involved in metabolic, inflammatory, and autoimmune diseases. In this review, current knowledge about the functions and pathophysiological implications of resistin in different human pathologies is summarized, although there is a significant lack of firm evidence regarding the specific role resistin plays in the "orchestra" of the numerous mediators of inflammation.

Resistin-like molecule-beta inhibits SGLT-1 activity and enhances GLUT2-dependent jejunal glucose transport

OBJECTIVE

An increased expression of RELM-beta (resistin-like molecule-beta), a gut-derived hormone, is observed in animal models of insulin resistance/obesity and intestinal inflammation. Intestinal sugar absorption is modulated by dietary environment and hormones/cytokines. The aim of this study was to investigate the effect of RELM-beta on intestinal glucose absorption.

RESEARCH DESIGN AND METHODS

Oral glucose tolerance test was performed in mice and rats in the presence and the absence of RELM-beta. The RELM-beta action on glucose transport in rat jejunal sacs, everted rings, and mucosal strips was explored as well as downstream kinases modulating SGLT-1 and GLUT2 glucose transporters.

RESULTS

Oral glucose tolerance test carried out in rodents showed that oral administration of RELM-beta increased glycemia. Studies in rat jejunal tissue indicated that mucosal RELM-beta promoted absorption of glucose from the gut lumen. RELM-beta had no effect on paracellular mannitol transport, suggesting a transporter-mediated transcellular mechanism. In studies with jejunal mucosa mounted in Ussing chamber, luminal RELM-beta inhibited SGLT-1 activity in line with a diminished SGLT-1 abundance in brush border membranes (BBMs). Further, the potentiating effect of RELM-beta on jejunal glucose uptake was associated with an increased abundance of GLUT2 at BBMs. The effects of RELM-beta were associated with an increased amount of protein kinase C betaII in BBMs and an increased phosphorylation of AMP-activated protein kinase (AMPK).

CONCLUSIONS

The regulation of SGLT-1 and GLUT2 by RELM-beta expands the role of gut hormones in short-term AMPK/protein kinase C mediated control of energy balance.

Serum Levels of Resistin in Allergic Rhinitis and its Relationship with Disease Severity

Background

Resistin, a recently discovered adipokine, has been shown to have proinflammatory properties in humans. The purpose of this study was to evaluate serum resistin levels in children with allergic rhinitis (AR) and to investigate its association with clinical disease severity, parameters of atopy and pro-/anti-inflammatory cytokines.

Methods

A case-controlled study was performed on 50 pediatric patients with persistent AR and 30 healthy controls with similar age, sex, and body mass index. Serum levels of resistin, parameters of atopy, and cytokines were analyzed. The nasal symptom scores were evaluated and patients were classified into mild (n = 20) and moderate-severe (n = 30) persistent AR.

Results

Serum levels of resistin were significantly increased in children with AR compared with controls (p < 0.001). Serum levels of resistin went hand in hand with disease severity as they were significantly higher in moderate-severe than mild persistent AR. In addition, they correlated positively with nasal symptom scores (r = 0.74; p < 0.001). A significant positive correlation was observed between serum levels of resistin and IL-6 (r = 0.358; p = 0.011).

Conclusion

Patients with persistent AR were found to have higher serum levels of resistin, and resistin levels increased with the progress of disease severity. Resistin may represent a novel link between inflammation and AR.

Resistin is elevated following traumatic joint injury and causes matrix degradation and release of inflammatory cytokines from articular cartilage in vitro

OBJECTIVE

Resistin is a secreted factor that is elevated in rheumatoid arthritis (RA) and believed to drive joint inflammation in vivo. This study was undertaken to determine if resistin is present in the joint following joint injury and to elucidate the role of resistin in cartilage degradation.

METHODS

The level of resistin was measured in paired synovial fluid (SF) and serum samples from patients following joint injury (anterior cruciate ligament, ACL or meniscus tear). Localization of resistin was visualized by immunohistochemistry of synovial tissue and cartilage from healthy and OA donors. Mouse and human cartilage cultures were used to assess the effect of resistin on cartilage metabolism.

RESULTS

In trauma patients, resistin levels declined with increasing time post injury. The resistin levels were highest in samples collected up to 1 week following traumatic injury (SF: 2980 pg/ml, serum: 7901 pg/ml) and lowest in samples collected 6-26 years post injury (SF: 686 pg/ml, serum: 5682 pg/ml). Resistin was shown to be expressed in macrophage-like cells in both healthy and OA synovial tissue. Treatment of mouse cartilage cultures with recombinant resistin led to a dose dependent loss of proteoglycan and induction of inflammatory cytokine and PGE(2) production. Recombinant resistin inhibited proteoglycan synthesis in human cartilage explants.

CONCLUSION

Resistin is elevated both systemically and locally in the weeks immediately following joint injury and has a direct effect on cartilage matrix turnover and cytokine production. Resistin may play a role in the early stages of trauma-induced OA and may represent a new therapeutic target to slow joint destruction in OA.

Association of -394C>G and -420C>G polymorphisms in the RETN gene with T2DM and CHD and a new potential SNP might be exist in exon 3 of RETN gene in Chinese

Genetic variations of the human RETN gene are associated with metabolic phenotypes, including obesity, insulin sensitivity, diabetes, and coronary heart disease (CHD). There are few studies of two gene variants, -394C>G and -420C>G, in Chinese population. This study investigated the distribution of RETN gene, single nucleotide polymorphisms (SNPs), in Chinese Han population and the association of the polymorphisms with type 2 diabetes mellitus (T2DM) and CHD. In a population-based, case-control genetic association study, a total of 961 subjects were recruited from the community, including 318 T2DM patients, 273 CHD patients, and 370 unrelated healthy control individuals. Serum lipid levels were detected. Two SNPs of RETN gene, -394C>G and -420C>G, were genotyped by PCR-RFLP. Unknown Polymorphisms were screened with the technique of denaturing high performance liquid chromatography (DHPLC). The frequencies of RETN -394G allele in T2DM group, CHD group, and control group were 0.3066, 0.3555, and 0.3481, respectively, which are met with the Hardy-Weinberg equilibrium. There is a significant difference of the comparison of sex in T2DM group of RETN gene SNP-394C>G (P < 0.05). Compared with controls, there was no significant difference in the distribution of genotypes and allele frequencies of -394C>G polymorphic site in T2DM patients and CHD patients, respectively. No direct association was found between the -394C>G polymorphism and T2DM or CHD. The frequencies of RETN -420G allele in T2DM group, CHD group, and control group were 0.4009, 0.3725, and 0.3859, respectively, which are met with the Hardy-Weinberg equilibrium. The frequencies of RETN -420G allele in T2DM groups and control groups of Chinese population are significantly different from those in European population (0.40 vs. 0.27, 0.39 vs. 0.26) (P < 0.01). Compared with controls, there was no significant difference in distribution of genotypes and allele frequencies of -420C>G polymorphic site in T2DM patients and CHD patients, respectively. No direct association was found between the -420C>G polymorphism and T2DM or CHD. In addition, we found new potential SNP +593G>C in exon 3 of RETN gene using DHPLC. The RETN gene exhibits sex and ethnic differences. +593G>C of RETN gene might be a new potential SNP in exon 3 of RETN gene. Association between SNP -394C>G and -420C>G of RETN gene with T2DM and CHD in Chinese needs more exploration.

Alternatively activated macrophage-derived RELM-{alpha} is a negative regulator of type 2 inflammation in the lung

Differentiation and recruitment of alternatively activated macrophages (AAMacs) are hallmarks of several inflammatory conditions associated with infection, allergy, diabetes, and cancer. AAMacs are defined by the expression of Arginase 1, chitinase-like molecules, and resistin-like molecule (RELM) alpha/FIZZ1; however, the influence of these molecules on the development, progression, or resolution of inflammatory diseases is unknown. We describe the generation of RELM-alpha-deficient (Retnla(-/-)) mice and use a model of T helper type 2 (Th2) cytokine-dependent lung inflammation to identify an immunoregulatory role for RELM-alpha. After challenge with Schistosoma mansoni (Sm) eggs, Retnla(-/-) mice developed exacerbated lung inflammation compared with their wild-type counterparts, characterized by excessive pulmonary vascularization, increased size of egg-induced granulomas, and elevated fibrosis. Associated with increased disease severity, Sm egg-challenged Retnla(-/-) mice exhibited elevated expression of pathogen-specific CD4(+) T cell-derived Th2 cytokines. Consistent with immunoregulatory properties, recombinant RELM-alpha could bind to macrophages and effector CD4(+) Th2 cells and inhibited Th2 cytokine production in a Bruton's tyrosine kinase-dependent manner. Additionally, Retnla(-/-) AAMacs promoted exaggerated antigen-specific Th2 cell differentiation. Collectively, these data identify a previously unrecognized role for AAMac-derived RELM-alpha in limiting the pathogenesis of Th2 cytokine-mediated pulmonary inflammation, in part through the regulation of CD4(+) T cell responses.

Resistin-like molecule-beta in scleroderma-associated pulmonary hypertension

Scleroderma is a systemic, mixed connective tissue disease that can impact the lungs through pulmonary fibrosis, vascular remodeling, and the development of pulmonary hypertension and right heart failure. Currently, little is known about the molecular mechanisms that drive this condition, but we have recently identified a novel gene product that is up-regulated in a murine model of hypoxia-induced pulmonary hypertension. This molecule, known as hypoxia-induced mitogenic factor (HIMF), is a member of the newly described resistin gene family. We have demonstrated that HIMF has mitogenic, angiogenic, vasoconstrictive, inflammatory, and chemokine-like properties, all of which are associated with vascular remodeling in the lung. Here, we demonstrate that the human homolog of HIMF, resistin-like molecule (RELM)-beta, is expressed in the lung tissue of patients with scleroderma-associated pulmonary hypertension and is up-regulated compared with normal control subjects. Immunofluorescence colocalization revealed that RELM-beta is expressed in the endothelium and vascular smooth muscle of remodeled vessels, as well as in plexiform lesions, macrophages, T cells, and myofibroblast-like cells. We also show that addition of recombinant RELM-beta induces proliferation and activation of ERK1/2 in primary cultured human pulmonary endothelial and smooth muscle cells. These results suggest that RELM-beta may be involved in the development of scleroderma-associated pulmonary hypertension.