Circulating levels of chemerin and adiponectin are higher in ulcerative colitis and chemerin is elevated in Crohn's disease

Upregulation of Nrf2 and Decreased Redox Signaling Contribute to Renoprotective Effects of Chemerin Receptor Blockade in Diabetic Mice

Chemerin, acting through its receptor ChemR23, is an adipokine associated with inflammatory response, glucose and lipid metabolism and vascular function. Although this adipokine has been associated with the development and progression of kidney disease, it is not clear whether the chemerin/ChemR23 system plays a role in renal function in the context of diabetes. Therefore, we sought to determine whether ChemR23 receptor blockade prevents the development and/or progression of diabetic nephropathy and questioned the role of oxidative stress and Nrf2 in this process. Renal redox state and function were assessed in non-diabetic lean db/m and diabetic obese db/db mice treated with vehicle or CCX832 (ChemR23 antagonist). Renal reactive oxygen species (ROS) production, which was increased in diabetic mice, was attenuated by CCX832. This was associated with an increase in Nox 4 expression. Augmented protein oxidation in db/db mice was not observed when mice were treated with CCX832. CCX832 also abrogated impaired Nrf2 nuclear activity and associated downregulation in antioxidants expression in kidneys from db/db mice. Our in vivo findings highlight the role of the redox signaling and Nrf2 system as renoprotective players during chemerin receptor blockade in diabetic mice. The chemerin/ChemR23 system may be an important target to limit renal dysfunction associated with obesity-related diabetes.

Hyperadiponectinemia During Infliximab Induction Therapy in Pediatric Crohn Disease

OBJECTIVES

The inflammatory process in Crohn disease (CD) involves the visceral fat, characterized by adipocyte hyperplasia and altered adipose tissue and serum concentrations of tumor necrosis factor (TNF), leptin, adiponectin and resistin. We investigated the effect of anti-TNF therapy with infliximab (IFX) on serum adipokine levels in pediatric CD.

METHODS

Serum concentrations of resistin (ng/mL), leptin (ng/mL), and total adiponectin (μg/mL) were assessed by enzyme-linked immunosorbent assays (ELISA) in 18 pediatric CD patients (mean age 15.0 ± 1.5 years) before first, second, and fourth IFX infusion (weeks 0, 2, and 14) and compared with baseline values from sex- and BMI-matched healthy controls (HC, mean age 13.4 ± 1.6 years).

RESULTS

At baseline, CD patients (mean age 15.0 ± 1.5 years, 10 of 18 boys) compared with HC (13.4 ± 1.6 years, 7 of 15 boys) had higher resistin levels (median 14.7 ng/mL, range 5.1-50.5 vs 7.3 ng/mL, 0.5-14.5); P = 0.0002). At weeks 2 and 14, resistin decreased to 6.9 ng/mL (2.9-16.8) (P < 0.0001) and 9.2 ng/mL (4.1-20.6; P = 0.0011), respectively. Leptin and adiponectin were comparable between patients and HC at baseline. Leptin increased in girls from 9.5 ng/mL (4.0-30.1) to 16.0 ng/mL (7.9-35.2; P = 0.0156) and 17.2 ng/mL (10.8- 26.8; P = 0.1953) at weeks 0, 2, and 14 respectively; with a trend in boys from 2 (0.6-12.9) to 2.8 (1.7-8.6; P = 0.0840) and 3.3 (1.3-4.6; P = 0.1309). Adiponectin peaked initially from 7.8 μg/mL (4.6-11.9) at week 0 to 9.2 μg/mL (4.1-20.7; P = 0.0005) at week 2 and thereafter fell to 6.5 μg/mL (3.0-12.7; P = 0.0182) at week 14.

CONCLUSIONS

TNF blockade is associated with changes in circulating adipokines. The marked early increase of the potent anti-inflammatory adiponectin may contribute to the rapid response to IFX in CD.

Adiponectin and adiponectin receptor 1 overexpression enhance inflammatory bowel disease

BACKGROUND

Adiponectin (ADN) is an adipokine derived from adipocytes. It binds to adiponectin receptor 1 and 2 (AdipoR1 and R2) to exert its function in regulating whole-body energy homeostasis and inflammatory responses. However, the role of ADN-AdipoR1 signaling in intestinal inflammation is controversial, and its role in the regulation of neutrophils is still unclear. Our goal was to clarify the role of AdipoR1 signaling in colitis and the effects on neutrophils.

METHODS

We generated porcine AdipoR1 transgenic mice (pAdipoR1 mice) and induced murine colitis using dextran sulfate sodium (DSS) to study the potential role of AdipoR1 in inflammatory bowel disease. We also treated a THP-1 macrophage and a HT-29 colon epithelial cell line with ADN recombinant protein to study the effects of ADN on inflammation.

RESULTS

After inducing murine colitis, pAdipoR1 mice developed more severe symptoms than wild-type (WT) mice. Treatment with ADN increased the expression of pro-inflammatory factors in THP-1 and HT-29 cells. Moreover, we also observed that the expression of cyclooxygenase2 (cox2), neutrophil chemokines (CXCL1, CXCL2 and CXCL5), and the infiltration of neutrophils were increased in the colon of pAdipoR1 mice.

CONCLUSIONS

Our study showed that ADN-AdipoR1 signaling exacerbated colonic inflammation through two possible mechanisms. First, ADN-AdipoR1 signaling increased pro-inflammatory factors. Second, AdipoR1 enhanced neutrophil chemokine expression and recruited neutrophils into the colonic tissue to increase inflammation.

Pleiotropic Associations of RARRES2 Gene Variants and Circulating Chemerin Levels: Potential Roles of Chemerin Involved in the Metabolic and Inflammation-Related Diseases

Chemerin, an adipokine and inflammatory mediator, is associated with metabolic, inflammation- and immune-mediated diseases. The genetic, clinical, and biomarker correlates of circulating chemerin levels have not been completely elucidated. We analyzed the determinants and correlates of retinoic acid receptor responder 2 (RARRES2; encoding chemerin) gene variants and chemerin levels in the Taiwanese population. In total, 612 individuals were recruited. Clinical and metabolic phenotypes, 13 inflammatory markers, 5 adipokines, and 6 single-nucleotide polymorphisms (SNPs) covering the RARRES2 region were analyzed. High chemerin levels and chemerin level tertiles were positively associated with multiple metabolic phenotypes and circulating inflammatory marker and adipokine levels and negatively associated with high-density lipoprotein cholesterol and adiponectin levels and estimated glomerular filtration rates (eGFRs). Genotype and haplotype analyses showed that RARRES2 SNPs were significantly associated with chemerin, fibrinogen, interleukin 6, and lipocalin 2 levels. Stepwise logistic regression analysis showed that C-reactive protein level, leptin level, triglyceride level, eGFR, rs3735167 genotypes, sex, and soluble P-selectin level were independently associated with chemerin levels. In conclusion, pleiotropic associations were noted between RARRES2 variants, circulating chemerin levels and multiple metabolic phenotypes and inflammatory marker levels. This study provides further evidence for the potential roles of chemerin in metabolic and inflammation-related diseases.

Association Between Adipokines Levels with Inflammatory Bowel Disease (IBD): Systematic Reviews

BACKGROUND

A combination of genetic and environmental factors is involved in the etiology of inflammatory bowel disease (IBD). Recent studies have shown that adipocytes play a crucial role, by actively participating in systemic immune responses in IBD patients. But findings remain controversial. To the best of our knowledge, no systematic review has evaluated the roles of adipokines in IBD, considering which this systematic review was undertaken to summarize the effects of these adipokines in IBD pathogenesis.

METHODS

For this review, articles published between 1980 and 2016 were identified from the PubMed, EMBASE, Scopus, and Cochrane and Google scholar databases. Thirteen articles were ultimately selected for inclusion in this systematic review.

RESULTS

Findings of the present study indicate that some of the adipokines such as leptin, adiponectin and resistin are associated with disease severity, body composition and glucose hemostasis in IBD patients, although some of these associations are stronger than others.

CONCLUSIONS

Overall findings indicate that some adipokines may play a crucial role in IBD severity or other IBD related outcomes. Further studies are recommended to confirm the results.

Absence of the Non-Signalling Chemerin Receptor CCRL2 Exacerbates Acute Inflammatory Responses In Vivo

Chemerin is a chemotactic protein that induces migration of several immune cells including macrophages, immature dendritic cells, and NK cells. Chemerin binds to three G protein-coupled receptors (GPCRs), including CCRL2. The exact function of CCRL2 remains unclear. CCRL2 expression is rapidly upregulated during inflammation, but it lacks the intracellular DRYLAIV motif required for classical GPCR downstream signalling pathways, and it has not been reported to internalise chemerin upon binding. The aim of this study was to investigate what role if any CCRL2 plays during acute inflammation. Using the zymosan- and thioglycollate-induced murine models of acute inflammation, we report that mice deficient in the Ccrl2 gene display exaggerated local and systemic inflammatory responses, characterised by increased myeloid cell recruitment. This amplified myeloid cell recruitment was associated with increased chemerin and CXCL1 levels. Furthermore, we report that the inflammatory phenotype observed in these mice is dependent upon elevated levels of endogenous chemerin. Antibody neutralisation of chemerin activity in Ccrl2-/- mice abrogated the amplified inflammatory responses. Importantly, chemerin did not directly recruit myeloid cells but rather increased the production of other chemotactic proteins such as CXCL1. Administration of recombinant chemerin to wild-type mice before inflammatory challenge recapitulated the increased myeloid cell recruitment and inflammatory mediator production observed in Ccrl2-/- mice. We have demonstrated that the absence of CCRL2 results in increased levels of local and systemic chemerin levels and exacerbated inflammatory responses during acute inflammatory challenge. These results further highlight the importance of chemerin as a therapeutic target in inflammatory diseases.

Increased serum chemerin level to predict early onset of aortic valve stenosis

Inflammation appears to be the cause of aortic valve (AoV) stenosis and identification of predictive biomarkers is therefore imperative. The aim of the current study was to evaluate the potential role of serum chemerin and fibroblast growth factor-21 (FGF-21) in the pathogenesis of the disease. A total of 102 patients were selected based on certain criteria and divided into an aortic stenosis group and a control group. Patients with AoV stenosis were subdivided into three groups depending on the severity according to the echocardiography criteria: Aortic jet velocity, Vmax (m/sec); mean pressure gradient, PG (mmHg); aortic valve area (AVA), cm²; and indexed AVA, cm²/m². Patients were graded as: Severe: Vmax >4 m/sec, PG >40 mmHg, AVA <1.0 cm², indexed AVA <0.6; moderate: Vmax 3.0–4.0 m/sec, PG 20–40 mmHg, AVA 1.0–1.5 cm², indexed AVA 0.60–0.85; mild: Vmax 2.5–2.9 m/sec, PG <20 mmHg, AVA >1.5 cm², indexed AVA >0.85. ELISA was used for the detection of chemerin and FGF-21. Post-hoc analysis with Tukey's correction was performed. The highest chemerin levels were found in mild and moderate AoV stenosis and decreased along with the grade of severity, compared with the control group. The FGF-21 level was increased in all the stenosis groups, reaching the highest level at severe stenosis. Receiver-operating characteristic analysis of chemerin in all the AoV stenosis groups without grading the severity included, area under the curve (AUC)=0.76; 0.70–0.80= fair; P<0.001 and for mild AoV stenosis was AUC=0.82; 0.80–0.90= good; P<0.001. In conclusion, chemerin is a good diagnostic biomarker for mild AoV stenosis, while FGF-21 is a moderate diagnostic marker.

Are adipocytokines inflammatory or metabolic mediators in patients with inflammatory bowel disease?

This study examined the adiponectin and leptin levels and insulin resistance (IR) in patients with inflammatory bowel disease (IBD) and the associations between these factors and IBD characteristics. Fasting serum leptin, adiponectin, glucose, and insulin levels, as well as inflammatory parameters, were measured in 105 patients with IBD (49 patients with Crohn’s disease [CD], 56 patients with ulcerative colitis [UC]) and 98 healthy controls [HC]. IR was evaluated using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Disease activity and severity in patients with UC were evaluated using the Truelove–Witts index, and patients with CD were evaluated using the Crohn’s Disease Activity Index. Serum adiponectin levels were found to be significantly lower in patients with CD and UC (p<0.001). Serum leptin levels were also found to be significantly higher in both the UC and CD groups (p<0.001). When HOMA-IR levels were compared, no significant difference was detected for either the CD or UC groups compared with the controls. In conclusion, it was shown that leptin levels increased and adiponectin levels decreased in patients with IBD, which is thought to be related to chronic inflammation. The effects of adipocytokines in patients with IBD with inflammatory and metabolic processes need to be investigated in further broader studies.

Serum chemerin in children with excess body weight may be associated with ongoing metabolic complications - A pilot study

PURPOSE

The aim of this study was to verify if serum chemerin in children correlates with body weight, fat mass, selected inflammatory markers, parameters of liver function, lipid and glucose metabolism.

MATERIALS AND METHODS

The study included children aged 5-17 years with normal body weight (<85th BMI percentile, n=43) or overweight (≥85th BMI percentile, n=58). Serum concentrations of chemerin were determined with ELISA.

RESULTS

Children with excess body weight presented with significantly higher serum concentrations of chemerin. Serum chemerin correlated positively with body weight, absolute BMI and its percentile, fat mass, systolic blood pressure, CRP, ALT, insulin and HOMA-IR.

CONCLUSIONS

Serum level of chemerin may serve as a measure of ongoing obesity-related inflammation, early marker of subclinical liver dysfunction and metabolic syndrome in overweight pediatric patients.

Serum Concentrations of Insulin, Ghrelin, Adiponectin, Leptin, Leptin Receptor and Lipocalin-2 in Children with Celiac Disease Who Do and Do Not Adhere to a Gluten-Free Diet

Background/Aims

The roles of the many bioactive peptides in the pathogenesis of celiac disease remain unclear. To evaluate the serum concentrations of insulin, ghrelin, adiponectin, leptin, leptin receptor, and lipocalin-2 in children with celiac disease who do and do not adhere to a gluten-free diet (GFD, intermittent adherence).

Methods

Prepubertal, pubertal, and adolescent celiac children were included in this study (74 girls and 53 boys on a GFD and 80 girls and 40 boys off of a GFD).

Results

Insulin levels in prepubertal (9.01±4.43 μIU/mL), pubertal (10.3±3.62 μIU/mL), and adolescent (10.8±4.73 μIU/mL) girls were higher than those in boys (5.88±2.02, 8.81±2.88, and 8.81±2.26 μIU/mL, respectively) and were neither age-dependent nor influenced by a GFD. Prepubertal children off of a GFD exhibited higher ghrelin levels than prepubertal children on a GFD. Adiponectin levels were not age-, sex- nor GFD-dependent. Adherence to a GFD had no effect on the expression of leptin, leptin receptor, and lipocalin-2.

Conclusions

Adherence to a GFD had no influence on the adiponectin, leptin, leptin receptor, and lipocalin-2 concentrations in celiac children, but a GFD decreased highly elevated ghrelin levels in prepubertal children. Further studies are required to determine whether increased insulin concentrations in girls with celiac disease is suggestive of an increased risk for hyperinsulinemia.

Methodological utility of chemerin as a novel biomarker of immunity and metabolism

Chemerin is a recently discovered adipokine with inflammatory and metabolic actions relevant for chronic disease development. However, evidence from human research on the role of chemerin in chronic disease risk is still lacking. We assessed the reliability of plasma chemerin concentrations measured on two occasions over a 4-month period in 207 apparently healthy participants. In addition, we explored the cross-sectional associations between chemerin and inflammatory biomarkers using Spearman partial correlation and multivariable linear regression analyses. Intra-individual reproducibility of chemerin measurements was assessed by calculating intraclass correlation coefficients (ICCs) and exploration of Bland-Altman plots. Reliability analyses revealed good reproducibility of chemerin measurements (ICC: 0.72 (95%-CI 0.65, 0.78)). Visual inspection of Bland-Altman plots confirmed that the two time point measurements had a high level of agreement. In correlation analyses, chemerin was positively correlated with adiposity measures (body mass index and waist circumference). In addition, independent of adiposity measures, chemerin was correlated with the biomarkers C-reactive protein, fatty acid-binding protein 4 and progranulin (Rho-s ranging from 0.23 to 0.37). In multivariable linear regression analysis, a combination of correlated factors including body mass index, waist circumference, C-reactive protein, progranulin and fatty acid-binding protein-4 explained 28.0% of chemerin concentrations. These findings demonstrate methodological utility of chemerin concentrations in population-based research setting. Human studies are highly warranted in order to provide further insights into the role of chemerin as a biomarker linking immunity and metabolism in relation to chronic disease risk.

Adipokines in Liver Cirrhosis

Liver fibrosis can progress to cirrhosis, which is considered a serious disease. The Child-Pugh score and the model of end-stage liver disease score have been established to assess residual liver function in patients with liver cirrhosis. The development of portal hypertension contributes to ascites, variceal bleeding and further complications in these patients. A transjugular intrahepatic portosystemic shunt (TIPS) is used to lower portal pressure, which represents a major improvement in the treatment of patients. Adipokines are proteins released from adipose tissue and modulate hepatic fibrogenesis. These proteins affect various biological processes that are involved in liver function, including angiogenesis, vasodilation, inflammation and deposition of extracellular matrix proteins. The best studied adipokines are adiponectin and leptin. Adiponectin protects against hepatic inflammation and fibrogenesis, and leptin functions as a profibrogenic factor. These and other adipokines are supposed to modulate disease severity in patients with liver cirrhosis. Consequently, circulating levels of these proteins have been analyzed to identify associations with parameters of hepatic function, portal hypertension and its associated complications in patients with liver cirrhosis. This review article briefly addresses the role of adipokines in hepatitis and liver fibrosis. Here, studies having analyzed these proteins in systemic blood in cirrhotic patients are listed to identify adipokines that are comparably changed in the different cohorts of patients with liver cirrhosis. Some studies measured these proteins in systemic, hepatic and portal vein blood or after TIPS to specify the tissues contributing to circulating levels of these proteins and the effect of portal hypertension, respectively.

Serum chemerin levels are independently associated with quality of life in colorectal cancer survivors: A pilot study

BACKGROUND

Colorectal cancer (CRC) survivors are known to experience various symptoms that significantly affect their quality of life (QOL); therefore, it is important to identify clinical markers related with CRC survivor QOL. Here we investigated the relationship between serum chemerin levels, a newly identified proinflammatory adipokine, and QOL in CRC survivors.

METHODS

A data of total of 110 CRC survivors were analysed in the study. Serum chemerin levels were measured with an enzyme immunoassay analyser. Functional Assessment of Cancer Therapy (FACT) scores were used as an indicator of QOL in CRC survivors.

RESULTS

Weak but not negligible relationships were observed between serum chemerin levels and FACT-General (G) (r = -0.22, p<0.02), FACT-Colorectal cancer (C) (r = -0.23, p<0.02) and FACT-Fatigue (F) scores (r = -0.27, p<0.01) after adjusting for confounding factors. Both stepwise and enter method multiple linear regression analyses confirmed that serum chemerin levels were independently associated with FACT-G (stepwise: β = -0.15, p<0.01; enter: β = -0.12, p = 0.02), FACT-C (stepwise: β = -0.19, p<0.01; enter; β = -0.14, p = 0.02) and FACT-F scores (stepwise: β = -0.23, p<0.01; enter: β = -0.20, p<0.01).

CONCLUSIONS

Our results demonstrate a weak inverse relationship between serum chemerin and CRC survivor QOL. Although it is impossible to determine causality, our findings suggest that serum chemerin levels may have a significant association with CRC survivor QOL. Further prospective studies are required to confirm the clinical significance of our pilot study.

Adipokine Chemerin Bridges Metabolic Dyslipidemia and Alveolar Bone Loss in Mice

Chemerin is an adipokine that regulates adipogenesis and metabolic functions of mature adipocytes mainly through the activation of chemokine-like receptor 1 (CMKLR1). Elevated levels of chemerin have been found in individuals with obesity, type 2 diabetes, and osteoporosis. This adipokine was identified as an inflammatory and metabolic syndrome marker. Considering that the association between metabolic syndrome and bone health remains unclear, the present study aimed to clarify the role of chemerin in the pathophysiology of bone loss induced by dyslipidemia, particularly modulating osteoclastogenesis. In vitro analyses showed a downregulation of CMKLR1 at the early stage of differentiation and a gradual increase at late stages. Strikingly, chemerin did not modify osteoclast differentiation markers or osteoclast formation; however, it increased the actin-ring formation and bone resorption activity in mature osteoclasts. The increased bone resorption activity induced by chemerin was effectively inhibited by CMKLR1 antagonist (CCX832). Chemerin boosting mature osteoclast activity involves ERK5 phosphorylation. Moreover, two models of dyslipidemia (high-fat diet [HFD]-treated C57/BL6 and db/db mice) exhibited significantly increased level of chemerin in the serum and gingival tissue. Morphometric analysis showed that HFD-treated and db/db mice exhibited increased alveolar bone loss compared to respective control mice, which was associated with an up-regulation of chemerin, CMKLR1 and cathepsin K mRNA expression in the gingival tissue. The treatment of db/db mice with CCX832 effectively inhibited bone loss. Antagonism of chemerin receptor also inhibited the expression of cathepsin K in the gingival tissue. Our results show that chemerin not only increases osteoclasts activity in vitro, but also that increased level of chemerin in dyslipidemic mice plays a critical role in bone homeostasis. © 2016 American Society for Bone and Mineral Research.

Beneficial Effect of Voluntary Exercise on Experimental Colitis in Mice Fed a High-Fat Diet: The Role of Irisin, Adiponectin and Proinflammatory Biomarkers

Inflammatory bowel diseases (IBDs) are a heterogeneous group of disorders exhibited by two major phenotypic forms: Crohn‘s disease and ulcerative colitis. Although the aetiology of IBD is unknown, several factors coming from the adipose tissue and skeletal muscles, such as cytokines, adipokines and myokines, were suggested in the pathogenesis of ulcerative colitis; however, it has not been extensively studied whether voluntary exercise can ameliorate that disorder. We explored the effect of moderate exercise (i.e., voluntary wheel running) on the disease activity index (DAI), colonic blood flow (CBF), plasma irisin and adiponectin levels and real-time PCR expression of proinflammatory markers in mesenteric fat in mice with 2,4,6-trinitrobenzenesulfonic acid (TNBS) colitis fed a high-fat diet (HFD) compared to those on a standard chow diet (SD). Macroscopic and microscopic colitis in sedentary SD mice was accompanied by a significant fall in CBF, some increase in colonic tissue weight and a significant increase in the plasma levels of tumour necrosis factor-alpha (TNF-α), IL-6, monocyte chemotactic protein 1 (MCP-1) and IL-13 (p < 0.05). In sedentary HFD mice, colonic lesions were aggravated, colonic tissue weight increased and the plasma TNF-α, IL-6, MCP-1, IL-1β and leptin levels significantly increased. Simultaneously, a significant decrease in the plasma irisin and adiponectin levels was observed in comparison with SD mice (p < 0.05). Exercise significantly decreased macroscopic and microscopic colitis, substantially increased CBF and attenuated the plasma TNF-α, IL-6, MCP-1, IL-1β and leptin levels while raising the plasma irisin and the plasma and WAT concentrations of adiponectin in HFD mice (p < 0.05). We conclude that: (1) experimental colitis is exacerbated in HFD mice, possibly due to a fall in colonic microcirculation and an increase in the plasma and mesenteric fat content of proinflammatory biomarkers; and (2) voluntary physical activity can attenuate the severity of colonic damage in mice fed a HFD through the release of protective irisin and restoration of plasma adiponectin.

CMKLR1 activation ex vivo does not increase proportionally to serum total chemerin in obese humans

Prochemerin is the inactive precursor of the adipokine chemerin. Proteolytic processing is obligatory for the conversion of prochemerin into active chemerin and subsequent regulation of cellular processes via the chemokine-like receptor 1 (CMKLR1). Elevated plasma or serum chemerin concentrations and differential processing of prochemerin have been reported in obese humans. The impact of these changes on CMKLR1 signalling in humans is unknown. The objective of this pilot study was to develop a cellular bioassay to measure CMKLR1 activation by chemerin present in human serum and to characterise how obesity modifies serum activation of CMKLR1 under fasted and fed conditions. Blood samples were collected from control (N = 4, BMI 20-25) and obese (N = 4, BMI >30) female subjects after an overnight fast (n = 2) and at regular intervals (n = 7) following consumption of breakfast over a period of 6 h. A cellular CMKLR1-luminescent reporter assay and a pan-chemerin ELISA were used to determine CMKLR1 activation and total chemerin concentrations, respectively. Serum total chemerin concentration (averaged across all samples) was higher in obese vs control subjects (17.9 ± 1.8 vs 10.9 ± 0.5 nM, P < 0.05), but serum activation of CMKLR1 was similar in both groups. The CMKLR1 activation/total chemerin ratio was lower in obese vs control subjects (0.33 ± 0.04 vs 0.58 ± 0.05, P < 0.05). After breakfast, serum total chemerin or CMKLR1 activation did not differ from baseline values. In conclusion, the unexpected observation that obese serum activation of CMKLR1 did not match increased total chemerin concentrations suggests impaired processing to and/or enhanced degradation of active chemerin in serum of obese humans.

Adipokines and the role of visceral adipose tissue in inflammatory bowel disease

Recently, adipocytes have been recognized as actively participating in local and systemic immune responses via the secretion of peptides detectable in relevant levels in the systemic circulation, the so-called "adipo(cyto)kines". Multiple studies appearing within the last 10-15 years have focused on the possible impact of adipose tissue depots on inflammatory bowel disease (IBD). Consequently, various hypotheses regarding the role of different adipokines in inflammatory diseases in general and in intestinal inflammatory processes in particular have been developed and have been further refined in recent years. After a focused summary of the data reported concerning the impact of visceral adipose tissue on IBD, such as Crohn's disease and ulcerative colitis, our review focuses on recent developments indicating that adipocytes as part of the innate immune system actively participate in antimicrobial host defenses in the context of intestinal bacterial translocation, which are of utmost importance for the homeostasis of the whole organism. Modulators of adipose tissue function and regulators of adipokine secretion, as well as modifiers of adipocytic pattern recognition molecules, might represent future potential drug targets in IBD.

Chemerin, visfatin, and vaspin serum levels in relation to bone mineral density in patients with inflammatory bowel disease

BACKGROUND

There is evidence that fat mass is correlated with bone mineral density (BMD) in inflammatory bowel disease (IBD), but data on the role of adipokines on this association are limited. The aim of this study was to investigate the serum levels of chemerin, visfatin, and vaspin, hormones that act as adipokines, in relation to BMD in patients with ulcerative colitis (UC) and Crohn's disease (CD).

PATIENTS AND METHODS

Serum from 120 IBD patients (68 CD, 52 UC) and 98 matched healthy controls (HC) was collected. Chemerin, visfatin, and vaspin levels were assessed using an enzyme-linked immunosorbent assay. BMD was determined for the lumbar spine and the proximal femur using dual-energy X-ray absorptiometry. Full-body composition scans were analyzed using enCORE software based on the absorptiometry system.

RESULTS

Serum chemerin was higher in IBD patients than HC [CD 13.67.1±5.8, UC 13.9±4.3 vs. HC 7.8±2.6 ng/ml, odds ratio (OR): 0.95, 95% confidence interval (CI) 0.93-0.98, P<0.0001]. Serum visfatin levels in CD patients were significantly higher than those in UC patients (9.3±14.01 vs. 6.5±7.2 ng/ml, OR: 0.86, 95% CI 0.80-0.92, P=0.039). In multivariate logistic regression analysis, a significant independent association of osteoporosis (T-score ≤2.5 SD) with age (OR: 1.04, 95% CI 1.01-1.08, P=0.02), visfatin (OR: 0.78, 95% CI 0.63-0.97, P=0.02), and chemerin levels (OR: 0.83, 95% CI 0.70-0.98, P=0.03), but not with BMI or body composition, was found.

CONCLUSION

Serum visfatin and chemerin levels are associated with the development of osteoporosis in IBD. These results suggest a role of visfatin and chemerin in the pathophysiology of osteoporosis in IBD.

Circulating serum chemerin levels are elevated in lipodystrophy

OBJECTIVE

Lipodystrophy (LD) is characterized by loss of adipose tissue, dysregulation of adipokines and severe metabolic complications. Regulation of the insulin resistance-inducing and proinflammatory adipokine chemerin has not been assessed in LD. Therefore, we determined chemerin serum levels in LD, chemerin mRNA expression in insulin-sensitive tissues of LD mice, as well as the impact of metreleptin treatment on circulating chemerin in LD patients.

RESEARCH DESIGN AND METHODS

Serum chemerin, as well as clinical and biochemical parameters of glucose metabolism, lipid metabolism, and inflammation, was measured in 37 LD patients and 37 age-, gender- and body mass index-matched controls. Furthermore, chemerin mRNA expression was determined in LD mice and controls. Moreover, circulating chemerin was assessed at five different time points in 10 LD patients treated with metreleptin over 1 year.

RESULTS

Median serum chemerin levels were significantly higher in 37 subjects with LD (234·3 μg/l) as compared to controls (204·0 μg/l) (P = 0·002). Multiple linear regression analysis showed that circulating chemerin was independently and positively associated with glycosylated haemoglobin A1c (HbA1c) and C-reactive protein (CRP). Chemerin mRNA expression was significantly increased 2·5-fold in visceral adipose tissue (VAT) and 5·3-fold in brown adipose tissue (BAT) of LD mice as compared to controls (P < 0·01). Circulating chemerin was not significantly altered by metreleptin treatment.

CONCLUSIONS

Circulating levels of the adipokine chemerin are elevated in LD, as well as independently and positively associated with HbA1c and CRP. Increased chemerin might originate from VAT and BAT.

Can exercise affect the course of inflammatory bowel disease? Experimental and clinical evidence

The inflammatory bowel disease (IBD) consisting of Crohn's disease (CD) and ulcerative colitis (UC) are defined as idiopathic, chronic and relapsing intestinal disorders occurring in genetically predisposed individuals exposed to environmental risk factors such as diet and microbiome changes. Since conventional drug therapy is expensive and not fully efficient, there is a need for alternative remedies that can improve the outcome in patients suffering from IBD. Whether exercise, which has been proposed as adjunct therapy in IBD, can be beneficial in patients with IBD remains an intriguing question. In this review, we provide an overview of the effects of exercise on human IBD and experimental colitis in animal models that mimic human disease, although the information on exercise in human IBD are sparse and poorly understood. Moderate exercise can exert a beneficial ameliorating effect on IBD and improve the healing of experimental animal colitis due to the activity of protective myokines such as irisin released from working skeletal muscles. CD patients with higher levels of exercise were significantly less likely to develop active disease at six months. Moreover, voluntary exercise has been shown to exert a positive effect on IBD patients' mood, weight maintenance and osteoporosis. On the other hand, depending on its intensity and duration, exercise can evoke transient mild systemic inflammation and enhances pro-inflammatory cytokine release, thereby exacerbating the gastrointestinal symptoms. We discuss recent advances in the mechanism of voluntary and strenuous exercise affecting the outcome of IBD in patients and experimental animal models.

Chemerin as an independent predictor of cardiovascular event risk

Currently, coronary artery disease (CAD) is considered a major ailment in humans with widespread prevalence. CAD also accounts for high mortality rates around the world that involves several known risk factors. Chemerin is a novel adipokinine that is associated with inflammation and adipogenesis. Furthermore, experimental and clinical data indicate that localized as well as circulating chemerin expression and activation are elevated in numerous metabolic and inflammatory diseases including psoriasis, obesity, type 2 diabetes, metabolic syndrome and cardiovascular disease. Chemerin is accepted as being a strong marker because the serum chemerin levels are increased in a CAD condition. However, the chimeric characteristics of chemerin have not been fully investigated. Although chemerin is known to be responsible for CAD development among other factors, authors still investigate it at the marker level. This review focuses on chemerin expression, processing, biological function and relevance to human diseases, and on the role of chemerin in the maintenance of a cardiovascular disease.

Chemerin in peritoneal sepsis and its associations with glucose metabolism and prognosis: a translational cross-sectional study

BACKGROUND

Stress hyperglycaemia (SHG) is a common complication in sepsis associated with poor outcome. Chemerin is an adipocytokine associated with inflammation and impaired glucose homeostasis in metabolic diseases such as type 2 diabetes (T2D). We aimed to investigate how alterations of circulating chemerin levels and corresponding visceral adipose tissue (VAT) expression are linked to glucose metabolism and prognosis in sepsis.

METHODS

Clinical data and tissue samples were taken from a cross-sectional study including control, T2D and sepsis patients, all undergoing laparotomy. A second independent patient cohort of patients with sepsis was included to evaluate associations with prognosis. This was complemented by a murine model of peritoneal infection and a high-fat diet. We analysed circulating chemerin by enzyme-linked immunosorbent assay and VAT messenger RNA (mRNA) expression by real-time polymerase chain reaction.

RESULTS

Circulating chemerin was increased in sepsis 1.69-fold compared with controls (p = 0.012) and 1.47-fold compared with T2D (p = 0.03). Otherwise, chemerin VAT mRNA expression was decreased in patients with sepsis (p = 0.006) and in septic diabetic animals (p = 0.009). Circulating chemerin correlated significantly with intra-operative glucose (r = 0.662; p = 0.01) and in trend with fasting glucose (r = 0.528; p = 0.052). After adjusting for body mass index or haemoglobin A1c, chemerin correlated in trend with insulin resistance evaluated using the logarithmised homeostasis model assessment of insulin resistance (r = 0.539, p = 0.071; r = 0.553, p = 0.062). Chemerin was positively associated with Acute Physiology and Chronic Health Evaluation II score in patients with sepsis (p = 0.036) and with clinical severity in septic mice (p = 0.031). In an independent study population, we confirmed association of chemerin with glucose levels in multivariate linear regression analysis (β = 0.556, p = 0.013). In patients with sepsis with SHG, non-survivors had significantly lower chemerin levels than survivors (0.38-fold, p = 0.006), while in patients without SHG, non-survivors had higher chemerin levels, not reaching significance (1.64-fold, p = 0.089). No difference was apparent in patients with pre-existing T2D (p = 0.44).

CONCLUSIONS

We show, for the first time to our knowledge, that chemerin is increased in sepsis and that it associates with impaired glucose metabolism and survival in these patients. It could be further evaluated as a biomarker to stratify mortality risk of patients with SHG.

Immunoregulatory Role of Myeloid-derived Cells in Inflammatory Bowel Disease

As the frontiers of immunological research expand, new insights into the pathogenesis of long poorly understood diseases, such as inflammatory bowel disease (IBD), are opening up new possible avenues for treatment. Myeloid-derived cells (i.e., monocytes, macrophages, neutrophils, and dendritic cells), long believed to be effector cells driving the initiation of inflammation, have been increasingly shown to have immunoregulatory effects previously underappreciated. Dysfunction in the immunoregulatory roles of these cells may play a part in the pathogenesis of a subset of patients with IBD. The role of myeloid-derived suppressor cells, initially described in cancer, have been shown to play an important role in the balancing of effector and regulatory T cells in inflammation as well, and their role in IBD is also explored. The potential for future cell-based therapies for IBD is enhanced by the advances being made in the understanding of the innate immune system in the intestine.

High plasma chemerin is associated with renal dysfunction and predictive for cardiovascular events - Insights from phenotype and genotype characterization

The novel adipokine chemerin, encoded by the RARRES2 gene, has been suggested to be linked to insulin resistance and to the metabolic syndrome (MetS). However, no well-defined cardiovascular profile has been reported and the association with coronary artery disease (CAD) is a matter of debate. Because there is a relation between renal dysfunction and CAD, we analyzed plasma chemerin levels and the estimated glomerular filtration rate (eGFR) in 495 patients undergoing coronary angiography for the evaluation of established or suspected stable CAD. Chemerin levels were higher in patients with Type 2 diabetes mellitus (T2DM, n=111) and the metabolic syndrome (MetS, n=147) than in subjects without T2DM (191.5±72.9 vs. 169.7±64.7ng/ml, p=0.001) or the MetS (201.2±71.0 vs. 163,1ng/ml, p<0.001), but did not differ significantly between patients with significant CAD (n=247) and those without significant CAD (177.1±67.0 vs. 171.7±67.2ng/ml, p=0.193). Analysis of covariance using age, sex, and BMI as covariates showed that chemerin was significantly and independently associated with eGFR (F=49.6, p<0.001). After an 8-year follow-up period, patients with high chemerin levels were more often affected by cardiovascular events (HR=1.72 [95% CI 1.19-2.47], p=0.004), even after appropriate adjustment for age, gender, BMI, as well as eGFR (adjusted HR 1.51 [95% CI 1.03-2.23], p=0.037). Given the cardiometabolic role of chemerin, we also applied a Cardio-Metabo Chip analysis and revealed a genome-wide significant association with SNPs (rs55709438, rs2444030, and rs3098423) located at chromosomal region 15q15-23, which were associated with metabolic traits and eGFR. This study for the first time demonstrates that high chemerin concentrations are significantly associated with renal impairment and predictive of cardiovascular events and that 15q15-23 might have an impact on chemerin levels beyond common genetic variations in RARRES2.

Local chemerin levels are positively associated with DSS-induced colitis but constitutive loss of CMKLR1 does not protect against development of colitis

Inflammatory bowel disease (IBD) is a family of disorders including ulcerative colitis and Crohn's disease that are characterized by chronic and relapsing intestinal inflammation. Increased production of proinflammatory mediators, possibly combined with low expression of anti-inflammatory mediators, is thought to promote the development and progression of IBD. In the current study, we demonstrate that expression, secretion, and processing of chemerin, a potent chemoattractant for cells expressing chemokine-like receptor 1 (CMKLR1), increased in the cecum and colon along a gradient positively associated with the severity of inflammation in dextran sodium sulfate (DSS)-induced colitis. We also show that levels of circulating bioactive chemerin increased following DSS treatment. At both 6-8 and 14-16 weeks of age, CMKLR1 knockout mice developed signs of clinical illness more slowly than wild type and had changes in circulating cytokine levels, increased spleen weight, and increased local chemerin secretion following DSS treatment. However, knockout mice ultimately developed similar levels of clinical illness and local inflammation as wild type. Finally, contrary to previous reports, intraperitoneal injection of bioactive chemerin had no effect on the severity of DSS-induced colitis. This suggests that local chemerin levels have a greater impact than circulating levels in the pathogenesis of colitis. Considered altogether, bioactive chemerin represents a novel biomarker for IBD severity, although strategies to modulate endogenous chemerin signaling other than chronic CMKLR1 loss are necessary in order to exploit chemerin as a therapeutic target for the treatment of IBD.

Chinese medicine enema for treatment of patients with mild to moderate ulcerative colitis: Therapeutic effect and regulatory effect on adiponectin

AIM: To observe the clinical effects of traditional Chinese medicine enema in patients with mild to moderate ulcerative colitis (UC) and its effect on adiponectin levels.

METHODS: A stratified randomized clinical trial was carried out. A total of 106 patients with UC were divided into two groups: an observation group and a control group. Patients in the observation group (n = 53) were given mesalazine and traditional Chinese medicine enema, while patients in the control group (n = 53) were given mesalazine only. The period of treatment was 4 wk. The adiponectin levels in patients with UC, disease activity index (DAI) and laboratory indicators were evaluated, and adverse reactions were recorded.

RESULTS: No case dropped out. The adiponectin level, disease activity index and laboratory indicators showed a significant decrease in both groups after treatment, and the decrease was more significant in the observation group.

CONCLUSION: Combination of traditional Chinese medicine enema and mesalazine is more effective and has fewer adverse effects than mesalazine alone in the treatment of patients with mild to moderate UC.

Adipokines influence the inflammatory balance in autoimmunity

Over the past few decades, our understanding of the role of adipose tissue has changed dramatically. Far from simply being a site of energy storage or a modulator of the endocrine system, adipose tissue has emerged as an important regulator of multiple important processes including inflammation. Adipokines are a diverse family of soluble mediators with a range of specific actions on the immune response. Autoimmune diseases are perpetuated by chronic inflammatory responses but the exact etiology of these diseases remains elusive. While researchers continue to investigate these causes, millions of people continue to suffer from chronic diseases. To this end, an increased interest has developed in the connection between adipose tissue-secreted proteins that influence inflammation and the onset and perpetuation of autoimmunity. This review will focus on recent advances in adipokine research with specific attention on a subset of adipokines that have been associated with autoimmune diseases.

Metabolic inflammation in inflammatory bowel disease: crosstalk between adipose tissue and bowel

Epidemiological studies show that both the incidence of inflammatory bowel disease (IBD) and the proportion of people with obesity and/or obesity-associated metabolic syndrome increased markedly in developed countries during the past half century. Obesity is also associated with the development of more active IBD and requirement for hospitalization and with a decrease in the time span between diagnosis and surgery. Patients with IBD, especially Crohn's disease, present fat-wrapping or "creeping fat," which corresponds to ectopic adipose tissue extending from the mesenteric attachment and covering the majority of the small and large intestinal surface. Mesenteric adipose tissue in patients with IBD presents several morphological and functional alterations, e.g., it is more infiltrated with immune cells such as macrophages and T cells. All these lines of evidence clearly show an association between obesity, adipose tissue, and functional bowel disorders. In this review, we will show that the mesenteric adipose tissue and creeping fat are not innocent by standers but actively contribute to the intestinal and systemic inflammatory responses in patients with IBD. More specifically, we will review evidence showing that adipose tissue in IBD is associated with major alterations in the secretion of cytokines and adipokines involved in inflammatory process, in adipose tissue mesenchymal stem cells and adipogenesis, and in the interaction between adipose tissue and other intestinal components (immune, lymphatic, neuroendocrine, and intestinal epithelial systems). Collectively, these studies underline the importance of adipose tissue for the identification of novel therapeutic approaches for IBD.

ChemR23, the receptor for chemerin and resolvin E1, is expressed and functional on M1 but not on M2 macrophages

ChemR23 is a G protein-coupled receptor that is triggered by two ligands, the peptide chemerin and the eicosapentaenoic acid-derived lipid mediator resolvin E1 (RvE1). Chemerin acts as a chemoattractant for monocytes and macrophages, whereas RvE1 promotes resolution of inflammation-inducing macrophage phagocytosis of apoptotic neutrophils. Although ChemR23-mediated signaling plays a role in mononuclear cell migration to inflamed tissue, as well as in the resolution of inflammation, its regulation in different polarization states of macrophages is largely unknown. We analyzed the expression and function of ChemR23 in monocytes and differently activated human primary macrophages. Using 5' RACE, we identified three transcription start sites and several splice variants of ChemR23 in both monocytes and macrophages. Although the promoters P1 and P3 are used equally in unpolarized macrophages, stimulation with LPS or IFN-γ leads to increased transcription from P3 in inflammatory M1 macrophages. Such ChemR23-expressing M1 macrophages are chemotactic to chemerin, whereas M2 macrophages not expressing ChemR23 surface receptor are not. Repolarization of ChemR23-expressing M1 macrophages with 10 nM RvE1 increases IL-10 transcription and phagocytosis of microbial particles, leading to a resolution-type macrophage distinct from the M2 phenotype. These results show that ChemR23 is tightly regulated in response to inflammatory and anti-inflammatory stimuli. The restricted expression of ChemR23 in naive and M1 macrophages supports the role of ChemR23 in the attraction of macrophages to inflamed tissue by chemerin and in the initiation of resolution of inflammation through RvE1-mediated repolarization of human M1 macrophages toward resolution-type macrophages.

Decreased levels of serum omentin-1 in patients with inflammatory bowel disease

BACKGROUND

Inflammation is involved in the mechanism of inflammatory bowel disease (IBD). Omentin, a newly discovered adipokine, is thought to play an anti-inflammatory role. This study aimed to determine whether serum levels of omentin-1 are associated with the presence and disease activity of IBD.

MATERIAL/METHODS

This study consisted of 192 patients with IBD: 100 with Crohn's disease [CD], 92 with ulcerative colitis [UC], and 104 healthy subjects. Serum levels of omentin-1 were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Serum omentin-1 levels were significantly decreased in CD and UC patients compared with healthy controls. Multivariable logistic regression analysis revealed that serum omentin-1 levels were inversely associated with the presence of CD and UC. Active CD and UC patients both had significantly decreased levels of serum omentin-1 compared with inactive CD and UC patients. In both CD and UC patients, serum omentin-1 levels were significantly associated with decreased levels of body mass index (BMI) and C-reactive protein (CRP).

CONCLUSIONS

Decreased serum omentin-1 levels could be considered as an independent predicting marker of the presence and disease activity of IBD.

Moderate exercise training attenuates the severity of experimental rodent colitis: the importance of crosstalk between adipose tissue and skeletal muscles

Although progress has been recently made in understanding of inflammatory bowel diseases (IBD), their etiology is unknown apart from several factors from adipose tissue and skeletal muscles such as cytokines, adipokines, and myokines were implicated in the pathogenesis of ulcerative colitis. We studied the effect high-fat diet (HFD; cholesterol up to 70%), low-fat diet (LFD; cholesterol up to 10%), and the normal diet (total fat up to 5%) in rats with TNBS colitis forced to treadmill running exercise (5 days/week) for 6 weeks. In nonexercising HFD rats, the area of colonic damage, colonic tissue weight, the plasma IL-1β, TNF-α, TWEAK, and leptin levels, and the expression of IL-1β-, TNF-α-, and Hif1α mRNAs were significantly increased and a significant fall in plasma adiponectin and irisin levels was observed as compared to LFD rats. In HFD animals, the exercise significantly accelerated the healing of colitis, raised the plasma levels of IL-6 and irisin, downregulated the expression of IL-1β, TNF-α, and Hif1α, and significantly decreased the plasma IL-1β, TNF α, TWEAK, and leptin levels. We conclude that HFD delays the healing of colitis in trained rats via decrease in CBF and plasma IL-1β, TNF-α, TWEAK, and leptin levels and the release of protective irisin.

Chemerin/chemR23 axis in inflammation onset and resolution

Chemerin is an adipokine secreted by adipocytes and associated with obesity, insulin resistance and metabolic syndrome. Different chemerin fragments with pro- or anti-inflammatory action can be produced, depending on the class of proteases predominating in the microenvironment. Chemerin binds to three receptors, especially to chemR23, expressed on various cells, as dendritic cells, macrophages and natural killer cells, regulating chemotaxis towards the site of inflammation and activation status. Recently, the chemerin/chemR23 axis has attracted particular attention for the multiple roles related to the control of inflammation, metabolism and cancerogenesis in different organs and systems as lung (allergy and cancer), skin (psoriasis, lupus, cancer, wound repair), cardiovascular system (lipid profile and atherosclerosis), reproductive apparatus (polycystic ovary syndrome, follicular homoeostasis), and digestive tract (inflammatory bowel diseases and cancer). This pathway may regulate immune responses by contributing both to the pathogenesis of inflammatory diseases and to the resolution of acute inflammation. Thus, chemerin-derived peptides or other substances that may affect the chemerin/chemR23 axis could be used in the future for the treatment of many diseases, including cancer at different sites.

New roles of the multidimensional adipokine: chemerin

The discovery of several adipokines with diverse activities and their involvement in regulation of various pathophysiological functions of human body has challenged the researchers. In the family of adipokine, chemerin is a novel and unique addition. Ever since the first report on chemerin as a chemo-attractant protein, there are numerous studies showing a multitasking capacity of chemerin in the maintenance of homeostasis, for the activation of natural killer cells, macrophages and dendritic cells in both innate and adaptive immunity. Its diversity ranges from generalized inflammatory cascades to being explicitly involved in the manifestation of arthritis, psoriasis and peritonitis. Its association with certain cancerous tissue may render it as a potential tumor marker. In present review, we aim to consolidate recent data of investigations on chemerin in context to functional characteristics with a special reference to its role as a metabolic signal in inflammation and non-metabolic syndromes.

The bone and fat connection in inflammatory bowel diseases

Osteopenia and osteoporosis are common manifestations in inflammatory bowel diseases (IBD) but the pathogenetic mechanism of bone loss in IBD is only partially understood. There is evidence that fat mass is an important determinant of the bone mineral density and adipose-derived factors seem to play an important role for the association between fat mass and bone mass. The association between adiposity and low bone density is rather poorly studied in IBD, but emerging data on adipokines in IBD in relation to osteoporosis provide a novel pathophysiological concept that may shed light on the etiology of bone loss in IBD. It could be suggested that adipokines interfere in bone metabolism by altering the sensitive balance between osteoblasts and osteoclasts although further studies in this setting are needed.

Serum adipokines in inflammatory bowel disease

AIM: To investigate serum adipokine levels in inflammatory bowel disease (IBD) patients before treatment and after achieving clinical remission.

METHODS: Serum concentrations of six adipokines (tissue growth factor-β1, adiponectin, leptin, chemerin, resistin, and visfatin) were studied in 40 subjects with active IBD [24 subjects with Crohn’s disease (CD) and in 16 subjects with ulcerative colitis (UC)] before and after three months of therapy with corticosteroids and/or azathioprine. Clinical diagnoses were based on ileocolonoscopy, computed tomography or magnetic resonance enterography and histological examination of mucosal biopsies sampled during endoscopy. Serum levels of adipokines were assessed by an indirect enzyme-linked immunosorbent assay. The control group was comprised of 16 age- and sex-matched healthy volunteers.

RESULTS: Baseline leptin concentrations were significantly decreased in both types of IBD compared to controls (8.0 ± 9.1 in CD and 8.6 ± 6.3 in UC vs 16.5 ± 10.1 ng/mL in controls; P < 0.05), and significantly increased after treatment only in subjects with CD (14.9 ± 15.1 ng/mL; P < 0.05). Baseline serum resistin concentrations were significantly higher in CD (19.3 ± 12.5 ng/mL; P < 0.05) and UC subjects (23.2 ± 11.0 ng/mL; P < 0.05) than in healthy controls (10.7 ± 1.1 ng/mL). Treatment induced a decrease in the serum resistin concentration only in UC subjects (14.5 ± 4.0 ng/mL; P < 0.05). Baseline serum concentrations of visfatin were significantly higher in subjects with CD (23.2 ± 3.2 ng/mL; P < 0.05) and UC (18.8 ± 5.3 ng/mL; P < 0.05) than in healthy controls (14.1 ± 5.3 ng/mL). Treatment induced a decrease in the serum visfatin concentrations only in CD subjects (20.4 ± 4.8 ng/mL; P < 0.05). Serum levels of adiponectin, chemerin and tissue growth factor-β1 did not differ between CD and UC subjects compared to healthy controls and also were not altered by anti-inflammatory therapy. Clinical indices of IBD activity did not correlate with adipokine levels.

CONCLUSION: IBD modulates serum adipokine levels by increasing resistin and visfatin release and suppressing leptin production.

The role of physical exercise in inflammatory bowel disease

We reviewed and analyzed the relationship between physical exercise and inflammatory bowel disease (IBD) which covers a group of chronic, relapsing, and remitting intestinal disorders including Crohn's disease (CD) and ulcerative colitis. The etiology of IBD likely involves a combination of genetic predisposition and environmental risk factors. Physical training has been suggested to be protective against the onset of IBD, but there are inconsistencies in the findings of the published literature. Hypertrophy of the mesenteric white adipose tissue (mWAT) is recognized as a characteristic feature of CD, but its importance for the perpetuation of onset of this intestinal disease is unknown. Adipocytes synthesize proinflammatory and anti-inflammatory cytokines. Hypertrophy of mWAT could play a role as a barrier to the inflammatory process, but recent data suggest that deregulation of adipokine secretion is involved in the pathogenesis of CD. Adipocytokines and macrophage mediators perpetuate the intestinal inflammatory process, leading to mucosal ulcerations along the mesenteric border, a typical feature of CD. Contracting skeletal muscles release biologically active myokines, known to exert the direct anti-inflammatory effects, and inhibit the release of proinflammatory mediators from visceral fat. Further research is required to confirm these observations and establish exercise regimes for IBD patients.

Chemerin aggravates DSS-induced colitis by suppressing M2 macrophage polarization

Chemerin is present in various inflammatory sites and is closely involved in tissue inflammation. Recent studies have demonstrated that chemerin treatment can cause either anti-inflammatory or pro-inflammatory effects according to the disease model being investigated. Elevated circulating chemerin was recently found in patients with inflammatory bowel disease (IBD); however, the role of chemerin in intestinal inflammation remains unknown. In this study, we demonstrated that the administration of exogenous chemerin (aa17-156) aggravated the severity of dextran sulfate sodium (DSS)-induced colitis, which was characterized by higher clinical scores, extensive mucosal damage and significantly increased local and systemic production of pro-inflammatory cytokines, including IL-6, TNF-α and interferon (IFN-γ). Interestingly, chemerin did not appear to influence the magnitudes of inflammatory infiltrates in the colons, but did result in significantly decreased colonic expression of M2 macrophage-associated genes, including Arginase 1 (Arg-1), Ym1, FIZZ1 and IL-10, following DSS exposure, suggesting an impaired M2 macrophage skewing in vivo. Furthermore, an in vitro experiment showed that the addition of chemerin directly suppressed M2 macrophage-associated gene expression and STAT6 phosphorylation in IL-4-stimulated macrophages. Significantly elevated chemerin levels were found in colons from DSS-exposed mice and from ulcerative colitis (UC) patients and appeared to positively correlate with disease severity. Moreover, the in vivo administration of neutralizing anti-chemerin antibody significantly improved intestinal inflammation following DSS exposure. Taken together, our findings reveal a pro-inflammatory role for chemerin in DSS-induced colitis and the ability of chemerin to suppress the anti-inflammatory M2 macrophage response. Our study also suggests that upregulated chemerin in inflamed colons may contribute to the pathogenesis of IBD.

Endothelial cell-derived chemerin promotes dendritic cell transmigration

ChemR23 is a chemotactic receptor expressed by APCs, such as dendritic cells, macrophages, and NK cells. Chemerin, the ChemR23 ligand, was detected by immunohistochemistry, to be associated with inflamed endothelial cells in autoimmune diseases, such as lupus erythematosus, psoriasis, and rheumatoid arthritis. This study reports that blood and lymphatic murine endothelial cells produce chemerin following retinoic acid stimulation. Conversely, proinflammatory cytokines, such as TNF-α, IFN-γ, and LPS, or calcitriol, are not effective. Retinoic acid-stimulated endothelial cells promoted dendritic cell adhesion under shear stress conditions and transmigration in a ChemR23-dependent manner. Activated endothelial cells upregulated the expression of the atypical chemotactic receptor CCRL2/ACKR5, a nonsignaling receptor able to bind and present chemerin to ChemR23(+) dendritic cells. Accordingly, activated endothelial cells expressed chemerin on the plasma membrane and promoted in a more efficient manner chemerin-dependent transmigration of dendritic cells. Finally, chemerin stimulation of myeloid dendritic cells induced the high-affinity binding of VCAM-1/CD106 Fc chimeric protein and promoted VCAM-1-dependent arrest to immobilized ligands under shear stress conditions. In conclusion, this study reports that retinoic acid-activated endothelial cells can promote myeloid and plasmacytoid dendritic cell transmigration across endothelial cell monolayers through the endogenous production of chemerin, the upregulation of CCRL2, and the activation of dendritic cell β1 integrin affinity.

Circulating leptin and adiponectin and their relation to glucose metabolism in children with Crohn's disease and ulcerative colitis

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC) result in metabolic consequences. We assessed circulating leptin and adiponectin concentrations and examined their relations to glucose metabolism in children with CD and UC.

METHODS

Circulating morning fasting concentrations of leptin, adiponectin, glucose, and insulin were measured in 32 children with CD and 18 children with UC. Insulin resistance (IR) and β-cell function were evaluated by the updated homeostatic model assessments (HOMA2-IR and HOMA2-B).

RESULTS

Leptin was positively related to BMI z-scores overall and in the CD and the UC subgroups (P < 0.001). A negative correlation between leptin and disease activity was observed in the entire population (P = 0.034) and in the UC (P = 0.03) group. None of the assessed parameters was related to adiponectin. Fourteen percent of the participants were insulin resistant (15.6% in the CD group and 11.1% in the UC group), significantly more than expected (P < 0.001). Leptin was associated with HOMA2-IR (overall: r = 0.29, P = 0.045). Pathway analysis suggested that, overall, disease activity and BMI significantly affect leptin, which in turn is the only correlate of HOMA2-IR.

CONCLUSION

Disease activity was significantly and inversely related to leptin in children with inflammatory bowel disease (IBD). A significant proportion of the patients had increased IR, which is positively related to circulating leptin.

Long-term outcome of tumor necrosis factor alpha antagonist's treatment in pediatric Crohn's disease

BACKGROUND

Anti tumor necrosis factor alpha (TNFα) agents have become widely used in pediatric inflammatory bowel disease (IBD). So far, only few studies examined the long-term results of anti-TNFα treatment in children with IBD.

METHODS

The long-term outcome of pediatric patients with IBD was assessed retrospectively in a multicenter cohort of children treated with anti-TNFα beyond induction treatment. Short- and long-term response rates, predictors for loss of response, data on growth and laboratory parameters were assessed.

RESULTS

120 patients [101 crohn's disease (CD), 19 ulcerative colitis (UC) or indeterminate colitis (IC)] received either infliximab or adalimumab. The mean age at initiation of anti-TNFα was 13.4 ± 3.9 years and the median duration of anti-TNFα treatment was 15 months (range: 2-90). Overall, 89% of the cohort experienced short-term response following induction. Response was associated with improvement in weight and BMI Z-scores (p<0.001) but not with linear growth. Responders experienced a significant decrease in erythrocyte sedimentation rate (ESR) and C reactive protein (CRP) during treatment (p<0.001). Albumin and hemoglobin both improved but only albumin increased significantly (p<0.001). The cumulative probability of losing response to anti-TNFα treatment was 17%, 38%, and 49% after 1, 3, and 5 years, respectively. Responders had a significantly lower weight and BMI Z-scores at initiation of anti-TNFα treatment in compared to non-responders (p=0.04 and 0.02 respectively).

CONCLUSIONS

Our long term cohort supports the current evidence on the effectiveness and safety of anti-TNFα treatment in children with IBD. Response to treatment was interestingly associated with lower weight and BMI.

You look all right to me: compromised nutritional status in paediatric patients with ulcerative colitis

OBJECTIVES

It is reported that malnutrition is not a feature of ulcerative colitis (UC). Body mass index (BMI) is frequently used clinically to indicate nutritional status; however, it is a proxy measure at best, and body cell mass (BCM) is a much more accurate representation. The present study aims to investigate BMI in patients with UC in relation to their BCM.

METHODS

A total of 18 patients (7M; 11F) had their nutritional status (BCM) measured using total body potassium⁴⁰ counting every 6 months to yield a total of 77 measurements. BCM measurements were adjusted for height and sex, and BMI was calculated as weight/height², with z scores determined for both parameters. Disease activity was determined using the Pediatric Ulcerative Colitis Activity Index.

RESULTS

Mean (±SD) height, weight, BMI, and BCM z scores were 0.39 (0.96), 0.20 (1.08), -0.05 (1.18), and -0.74 (1.41), respectively. No correlation was found between BMI and BCM z scores, and these z scores were significantly different (P=0.02), particularly in the moderate/severe disease activity group (P=0.01). Mean BCM z scores were -0.69 (1.65) of a z score below BMI z scores. Furthermore, where BMI z scores showed no relation to disease activity and no differences between disease activity categories, BCM z scores were significantly negatively correlated (r=-0.32, P=0.01), with significantly lower scores found in the moderate/severe group (P=0.01).

CONCLUSIONS

Simply calculating BMI in patients with UC does not give adequate information regarding nutritional status, and more accurate, yet easily accessible "bedside" techniques need to be determined to improve patient care.