Link between chemerin, central obesity, and parameters of the Metabolic Syndrome: findings from a longitudinal study in obese children participating in a lifestyle intervention

CMKLR1 senses chemerin/resolvin E1 to control adipose thermogenesis and modulate metabolic homeostasis

Induction of beige fat for thermogenesis is a potential therapy to improve homeostasis against obesity. β3-adrenoceptor (β3-AR), a type of G protein-coupled receptor (GPCR), is believed to mediate the thermogenesis of brown fat in mice. However, β3-AR has low expression in human adipose tissue, precluding its activation as a standalone clinical modality. This study aimed at identifying a potential GPCR target to induce beige fat. We found that chemerin chemokine-like receptor 1 (CMKLR1), one of the novel GPCRs, mediated the development of beige fat via its two ligands, chemerin and resolvin E1 (RvE1). The RvE1 levels were decreased in the obese mice, and RvE1 treatment led to a substantial improvement in obese features and augmented beige fat markers. Inversely, despite sharing the same receptor as RvE1, the chemerin levels were increased in obesogenic conditions, and chemerin treatment led to an augmented obese phenotype and a decline of beige fat markers. Moreover, RvE1 and chemerin induced or restrained the development of beige fat, respectively, via the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway. We further showed that RvE1 and chemerin regulated mTORC1 signaling differentially by forming hydrogen bonds with different binding sites of CMKLR1. In conclusion, our study showed that RvE1 and chemerin affected metabolic homeostasis differentially, suggesting that selectively modulating CMKLR1 may be a potential therapeutic target for restoring metabolic homeostasis.

Association of hepatokines with markers of endothelial dysfunction and vascular reactivity in obese adolescents

OBJECTIVES

Obesity-induced insulin resistance (IR) is known to influence hepatic cytokines (hepatokines), including fibroblast growth factor (FGF-21), fetuin-A, and chemerin. This study aimed to investigate the association between hepatokines and markers of endothelial dysfunction and vascular reactivity in obese adolescents.

METHODS

A total of 45 obese adolescents were categorized into three groups based on glucose tolerance: normal glucose tolerance (NGT), prediabetes (PD), and type 2 diabetes (T2D). We examined the relationships between FGF-21, fetuin-A, and chemerin with endothelial markers (plasminogen activator inhibitor-1 [PAI-1], intercellular adhesion molecule-1 [ICAM-1], and vascular cell adhesion marker-1 [VCAM-1]) and vascular surrogates (brachial artery reactivity testing [BART] and peak reactive hyperemia [PRH]).

RESULTS

Obese adolescents (age 16.2±1.2 years; 62 % female, 65 % Hispanic) with NGT (n=20), PD (n=14), and T2D (n=11) had significant differences between groups in BMI; waist-hip ratio (p=0.05), systolic BP (p=0.008), LDL-C (p=0.02), PAI-1 (p<0.001). FGF-21 pg/mL (mean±SD: NGT vs. PD vs. T2D 54±42; 266±286; 160±126 p=0.006) and fetuin-A ng/mL (266±80; 253±66; 313±50 p=0.018), were significantly different while chemerin ng/mL (26±5; 31±10; 28±2) did not significantly differ between the groups. Positive correlations were found between chemerin and both PAI-1 (r=0.6; p=0.05) and ICAM-1 (r=0.6; p=0.05), FGF-21 and PAI-1 (r=0.6; p<0.001), and fetuin-A with TNFα (r=-0.4; p=0.05). Negative correlations were found between chemerin and PRH (r= -0.5; p=0.017) and fetuin-A and PRH (r=-0.4; p=0.05).

CONCLUSIONS

In our cohort, IR predicted higher FGF-21 levels suggesting a linear relationship may exist between the two parameters. Hepatokines can augment alterations in the microvascular milieu in obese adolescents as demonstrated by their associations with the markers PAI-1, ICAM-1, and PRH.

Adolescent obesity and ANGPTL8: correlations with high sensitivity C-reactive protein, leptin, and chemerin

Angiopoietin-like proteins (ANGPTLs) mediate many metabolic functions. We had recently reported increased plasma levels of ANGPTL8 in obese adults of Arab ethnicity. However, data on ANGPTL8 levels in adolescent obesity is lacking. Arab population is characterized by a rapid transition, due to sudden wealth seen in the post-oil era, in lifestyle, food habits and extent of physical activity. We adopted a cross-sectional study on Arab adolescents from Kuwait to examine the role of ANGPTL8 in adolescent obesity. The study cohort included 452 adolescents, aged 11-14 years, recruited from Middle Schools across Kuwait. BMI-for-age growth charts were used to categorize adolescents as normal-weight, overweight, and obese. ELISA and bead-based multiplexing assays were used to measure plasma levels of ANGPTL8 and other inflammation and obesity-related biomarkers. Data analysis showed significant differences in the plasma levels of ANGPTL8 among the three subgroups, with a significant increase in overweight and obese children compared to normal-weight children. This observation persisted even when the analysis was stratified by sex. Multinomial logistic regression analysis illustrated that adolescents with higher levels of ANGPTL8 were 7 times more likely to become obese and twice as likely to be overweight. ANGPTL8 levels were correlated with those of hsCRP, leptin and chemerin. ANGPTL8 level had a reasonable prognostic power for obesity with an AUC of 0.703 (95%-CI=0.648-0.759). These observations relating to increased ANGPTL8 levels corresponding to increased BMI-for-age z-scores indicate that ANGPTL8, along with hsCRP, leptin and chemerin, could play a role in the early stages of obesity development in children. ANGPTL8 is a potential early marker for adolescent obesity and is associated with well-known obesity and inflammatory markers.

The Role of Adipokines and Myokines in the Pathogenesis of Different Obesity Phenotypes-New Perspectives

Obesity is a characteristic disease of the twenty-first century that is affecting an increasing percentage of society. Obesity expresses itself in different phenotypes: normal-weight obesity (NWO), metabolically obese normal-weight (MONW), metabolically healthy obesity (MHO), and metabolically unhealthy obesity (MUO). A range of pathophysiological mechanisms underlie the occurrence of obesity, including inflammation, oxidative stress, adipokine secretion, and other processes related to the pathophysiology of adipose tissue (AT). Body mass index (BMI) is the key indicator in the diagnosis of obesity; however, in the case of the NWO and MONW phenotypes, the metabolic disturbances are present despite BMI being within the normal range. On the other hand, MHO subjects with elevated BMI values do not present metabolic abnormalities. The MUO phenotype involves both a high BMI value and an abnormal metabolic profile. In this regard, attention has been focused on the variety of molecules produced by AT and their role in the development of obesity. Nesfatin-1, neuregulin 4, myonectin, irisin, and brain-derived neurotrophic factor (BDNF) all seem to have protective effects against obesity. The primary mechanism underlying the action of nesfatin-1 involves an increase in insulin sensitivity and reduced food intake. Neuregulin 4 sup-presses lipogenesis, decreases lipid accumulation, and reduces chronic low-grade inflammation. Myonectin lowers the amount of fatty acids in the bloodstream by increasing their absorption in the liver and AT. Irisin stimulates the browning of white adipose tissue (WAT) and consequently in-creases energy expenditure, additionally regulating glucose metabolism. Another molecule, BDNF, has anorexigenic effects. Decorin protects against the development of hyperglycemia, but may also contribute to proinflammatory processes. Similar effects are shown in the case of visfatin and chemerin, which may predispose to obesity. Visfatin increases adipogenesis, causes cholesterol accumulation in macrophages, and contributes to the development of glucose intolerance. Chemerin induces angiogenesis, which promotes the expansion of AT. This review aims to discuss the role of adipokines and myokines in the pathogenesis of the different obesity phenotypes.

Progress in the contrary effects of glucagon-like peptide-1 and chemerin on obesity development

Glucagon-like peptide-1 (GLP-1), secreted by intestinal L-cells, plays a pivotal role in the modulation of β-cell insulin secretion in a glucose-dependent manner, concurrently promoting β-cell survival and β-cell mass. Notably, GLP-1 has emerged as an effective second-line treatment for type 2 diabetes mellitus, gaining further prominence for its pronounced impact on body weight reduction, positioning it as a potent antiobesity agent. However, the mechanism by which GLP-1 improves obesity remains unclear. Some reports suggest that this mechanism may be associated with the regulation of adipokine synthesis within adipose tissue. Chemerin, a multifunctional adipokine and chemokine, has been identified as a pivotal player in adipocyte differentiation and the propagation of systemic inflammation, a hallmark of obesity. This review provides a comprehensive overview of the mechanisms by which GLP-1 and chemerin play crucial roles in obesity and obesity-related diseases. It discusses well-established aspects, such as their effects on food intake and glycolipid metabolism, as well as recent insights, including their influence on macrophage polarization and adipose tissue thermogenesis. GLP-1 has been shown to increase the population of anti-inflammatory M2 macrophages, promote brown adipose tissue thermogenesis, and induce the browning of white adipose tissue. In contrast, chemerin exhibits opposite effects in these processes. In addition, recent research findings have demonstrated the promising potential of GLP-1-based therapies in directly or indirectly regulating chemerin expression. In an intriguing reciprocal relationship, chemerin has also been newly identified as a negative regulator of GLP-1 in vivo. This review delineates the intricate interplay between GLP-1 and chemerin, unraveling their mutual inhibitory interactions. To the best of our knowledge, no previous reviews have focused on this specific topic, making this review particularly valuable in expanding our understanding of the endocrine mechanisms of obesity and providing potential strategies for the treatment of obesity and related diseases.

The effect of exercise training on serum concentrations of chemerin in patients with metabolic diseases: a systematic review and meta-analysis

CONTEXT

Elevated serum concentrations of chemerin is a significant factor in the development of metabolic disorders.

OBJECTIVE

This systematic review and meta-analysis evaluated the influence of exercise training on serum concentrations of chemerin in patients with metabolic diseases.

METHODS

Thirteen studies including 463 participants were included and analysed using a random-effects model to calculate weighted mean differences with 95% confidence intervals.

RESULTS

Results indicated that exercise training significantly decreased serum concentrations of chemerin in patients with metabolic diseases when compared with controls. Subgroup analysis showed that exercise training resulted in decreases in serum concentrations of chemerin in men, however, this was not significant in women. Moreover, subgroup analyses based on the type of exercise did not reveal differential effects on serum concentrations of chemerin.

CONCLUSION

Exercise training may produce improvements in serum concentrations of chemerin in patients with metabolic diseases. Further longer-term studies are needed to confirm these findings.

The effects of exercise training on serum concentrations of chemerin in individuals with overweight and obesity: a systematic review, meta-analysis, and meta-regression of 43 clinical trials

CONTEXT

Elevated serum concentrations of chemerin is a significant factor in the development of metabolic disorders in individuals with overweight and obesity.

OBJECTIVE

This systematic review, meta-analysis, and meta-regression evaluated the effects of exercise training on serum concentrations of chemerin in individuals with overweight and/or obesity.

METHODS

Studies published up to January 2021 were identified through four databases. Forty-three studies including 1271 participants were included and analysed using a random-effects model to calculate weighted mean differences with 95% confidence intervals.

RESULTS

Results indicated that exercise training significantly decreased serum concentrations of chemerin in individuals with overweight and/or obesity. Subgroup analysis showed that all types of exercise (aerobic, resistance, and combined training) interventions but not high-intensity interval training decreased serum concentrations of chemerin. Subgroup analysis based on baseline body mass index (BMI), gender, and intervention duration showed significant declines in serum concentrations of chemerin. Meta-regression analysis indicated a linear relationship between changes in body fat percentage (BFP) with serum concentrations of chemerin.

CONCLUSION

Exercise training may decrease serum concentrations of chemerin in individuals with overweight and/or obesity. The chemerin-lowering effects of exercise might be related to declines in BFP. Further studies are needed to confirm these findings.

The effects of pro-, pre-, and synbiotics supplementation on polycystic ovary syndrome: an umbrella review of meta-analyses of randomized controlled trials

Background

Synbiotics, refer to a combination of probiotics and prebiotics in a form of synergism that beneficially affect the host's health by alternating the composition and/or function of the gut microbiota. Numerous meta-analyses of randomized clinical trials have proven that pro, pre-, and synbiotics supplementation has health outcomes in women with polycystic ovary syndrome (PCOS). However, the strength and quality of this evidence in aggregate have not yet been synthesized in great detail.

Methods

PubMed, Scopus, Web of Sciences, and Google Scholar were searched up to March 2023. We pooled the mean difference and its 95% confidence interval (CI) by applying a random-effects model.

Results

Overall, nine meta-analyses including a total of 12 trials were identified. The results of the present study indicated that probiotic supplementation significantly reduced the homeostatic model assessment for insulin resistance (HOMA-IR; WMD: -0.29, 95% CI: -0.57 to -0.02, p = 0.03, n = 4; moderate certainty) and fasting glucose concentration (FGC; WMD: -7.5 mg/dL, 95% CI: -13.60 to -0.51, p = 0.03; n = 4; low certainty). Moreover, synbiotic supplementation had beneficial effects on glycemic control, lipid profile, and hormonal parameters, but the certainty of the evidence was rated as low to very low. However, supplementation with pro-/synbiotics did not affect inflammation and oxidative stress in women with PCOS. Furthermore, waist/hip circumference, fasting glucose concentration, lipid profile, dehydroepiandrosterone sulfate, high-sensitivity C-reactive protein, and hirsutism score were significantly reduced after prebiotics supplementation with low certainty of evidence.

Conclusion

Although pro-, pre-, and synbiotics supplementation had beneficial effects on some PCOS-related outcomes, the certainty of the evidence was rated as low to very low. Therefore, further well-designed RCTs might help to confirm our findings in women with PCOS.

Alternative splicing is not a key source of chemerin isoforms diversity

BACKGROUND

Chemerin is a chemoattractant protein with adipokine and antimicrobial properties encoded by the retinoic acid receptor responder 2 (RARRES2) gene. Chemerin bioactivity largely depends on carboxyl-terminal proteolytic processing that generates chemerin isoforms with different chemotactic, regulatory, and antimicrobial potentials. While these mechanisms are relatively well known, the role of alternative splicing in generating isoform diversity remains obscure.

METHODS AND RESULTS

Using rapid amplification of cDNA ends (RACE) PCR, we determined RARRES2 transcript variants present in mouse and human tissues and identified novel transcript variant 4 of mouse Rarres2 encoding mChem153K. Moreover, analyses of real-time quantitative PCR (RT-qPCR) and publicly-available next-generation RNA sequencing (RNA-seq) datasets showed that different alternatively spliced variants of mouse Rarres2 are present in mouse tissues and their expression patterns were unaffected by inflammatory and infectious stimuli except brown adipose tissue. However, only one transcript variant of human RARRES2 was present in liver and adipose tissue.

CONCLUSION

Our findings indicate a limited role for alternative splicing in generating chemerin isoform diversity under all tested conditions.

Associations of adiposity and adipokine concentrations with anti- and oxidative markers in Brazilian children

OBJECTIVE

The aim of this study was to evaluate the association of body fat, anti- and inflammatory adipokines with anti- and oxidative markers.

METHODS

We conducted a cross-sectional study with 378 schoolchildren ages 8 to 9 y in Viçosa, Minas Gerais, Brazil. We obtained information on sociodemographic and lifestyle characteristics via questionnaires, measured height and weight, and estimated body fat by dual energy x-ray absorptiometry. Blood sample was collected to analyze the adipokines (adiponectin, leptin, chemerin, and retinol-binding protein 4) by enzyme-linked immunosorbent assay based on the sandwich principle; and anti- and oxidant markers (plasma ferric reducing antioxidant power [FRAP], superoxide dismutase [SOD], and malondialdehyde [MDA]) by enzymatic methods. Concentrations of anti- and oxidant markers were compared by percent body fat quartiles and adipokine concentrations terciles using of linear regression adjusted for potential confounders.

RESULTS

Total and central body fat were positively associated with FRAP. Every 1 standard deviation (SD) of total fat was associated with 4.8 higher FRAP (95% confidence interval [CI], 2.7-7). Additionally, every 1 SD of truncal, android, and gynoid fat were associated with, respectively, 5, 4.6, and 4.6 higher FRAP (95% CI, 2.9-7.1; 2.6-6.7; and 2.4-6.8, respectively). However, adiponectin was inversely associated with FRAP; every adiponectin SD was related to -2.2 lower FRAP (95% CI, -3.9 to -0.5). Chemerin was positively associated with SOD [5.4 (95% CI, 1.9-8.8) SOD units per chemerin SD].

CONCLUSIONS

The body fat measures and adiposity-related inflammation (chemerin) were positively associated with antioxidative markers in children, whereas the adiponectin (anti-inflammatory marker) was inversely associated with FRAP (antioxidative marker).

The link between vitamin D, chemerin and metabolic profile in overweight and obese children - preliminary results

Background

Vitamin D affects adipogenesis, oxidative stress, inflammation, secretion of adipocytokines, lipid metabolism and thermogenesis. Some researchers postulate that those effects could be exerted by the influence of vitamin D on chemerin levels.

Aim of the study

We aimed to investigate if there is a link between serum 25-hydroksyvitamin D [25(OH)D], chemerin and metabolic profile in overweight and obese children before and after vitamin D supplementation.

Material and methods

The prospective study included 65 overweight and obese children aged 9.08-17.5 years and 26 peers as a control. None of the patients in the study group had received vitamin D within the last twelve months before the study.

Results

The study group had lower baseline 25(OH)D (p<0.001) and higher chemerin (p<0.001), triglycerides (TG, p<0.001), triglycerides/high density lipoprotein cholesterol (TG/HDL-C, p<0.001), C-reactive protein (CRP, p<0.05), fasting insulin (p<0.001), Homeostasis Model Assessment - Insulin Resistance (HOMA-IR, p<0.001), alanine aminotransferase (ALT, p<0.001) and uric acid (p<0.001) compared to the control group. Baseline vitamin D was related to fasting insulin (R=-0.29, p=0.021), HOMA-IR (R=-0.30, p=0.016), HDL-C (R=0.29, p=0.020) and uric acid (R=-0.28, p=0.037) in the study group. Baseline chemerin was related to insulin at 30' (R=0.27, p=0.030), 60' (R=0.27, p=0.033), 90' (R=0.26, p=0.037) and 120' (R=0.26, p=0.040) during the oral glucose tolerance test (OGTT) and ALT (R=0.25, p=0.041) in the study group. Correlation between vitamin D and chemerin (R=-0.39, p=0.046) was found only in the control group. After six months of vitamin D supplementation a decrease in CRP (p<0.01), total cholesterol (p<0.05), ALT (p<0.01), glucose at 150' OGTT (p<0.05) was observed. Moreover, we noticed a tendency for negative association between 25(OH)D and chemerin levels (p=0.085). Multivariable backward linear regression models were build using baseline vitamin D, baseline chemerin and six months chemerin as the dependent variables.

Conclusions

Our study confirmed that vitamin D has positive effect on metabolic profile in overweight and obese children. The relationship between vitamin D and chemerin is not clear, nevertheless we have observed a tendency to decrease chemerin concentrations after improving vitamin D status, even without a significant reduction in body fat mass.

Role of Chemerin in Cardiovascular Diseases

(1) Background: Obesity is closely connected to the pathophysiology of cardiovascular diseases (CVDs). Excess fat accumulation is associated with metabolic malfunctions that disrupt cardiovascular homeostasis by activating inflammatory processes that recruit immune cells to the site of injury and reduce nitric oxide levels, resulting in increased blood pressure, endothelial cell migration, proliferation, and apoptosis. Adipose tissue produces adipokines, such as chemerin, that may alter immune responses, lipid metabolism, vascular homeostasis, and angiogenesis. (2) Methods: We performed PubMed and MEDLINE searches for articles with English abstracts published between 1997 (when the first report on chemerin identification was published) and 2022. The search retrieved original peer-reviewed articles analyzed in the context of the role of chemerin in CVDs, explicitly focusing on the most recent findings published in the past five years. (3) Results: This review summarizes up-to-date findings related to mechanisms of chemerin action, its role in the development and progression of CVDs, and novel strategies for developing chemerin-targeting therapeutic agents for treating CVDs. (4) Conclusions: Extensive evidence points to chemerin's role in vascular inflammation, angiogenesis, and blood pressure modulation, which opens up exciting perspectives for developing chemerin-targeting therapeutic agents for the treatment of CVDs.

Assessment of serum chemerin levels in acanthosis nigricans: A case-control study

BACKGROUND

Acanthosis nigricans (AN) is an asymptomatic skin condition linked to several underlying systemic conditions. Chemerin is an adipokine that increases during inflammatory disorders such as metabolic syndrome (MetS).

AIMS

This case-control study investigates the link between AN and the underlying MetS and serum levels of chemerin in individuals with obesity.

PATIENTS/METHODS

Twenty-five adults with AN and obesity (body mass index [BMI] > 30 kg/m² ), 25 adults with obesity but no AN, and 25 healthy controls (BMI < 30 kg/m² ) had their lipid profiles and serum chemerin concentrations examined.

RESULTS

The neck (80.0%) and axilla (68.0%) were the most common sites of AN. In participants with obesity, either alone or with AN, serum chemerin concentrations were significantly higher than in the control group (p < 0.001). Participants with obesity and AN had significantly higher levels of cholesterol, triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), and serum chemerin levels (p < 0.001), and significantly lower high-density lipoprotein cholesterol (HDL-c) levels (p < 0.001) when compared to participants with obesity alone. All participants with obesity and AN (100%) and 88% of those with obesity alone had MetS. Logistic regression revealed that systolic blood pressure >130 mmHg, diastolic blood pressure >85 mmHg, waist circumference >90 cm, TG >150 mg/dl, HDL-c <45 mg/dl, fasting blood glucose >100 mg/dl, and serum chemerin >300 ng/ml were significant (p < 0.05) risk factors for AN.

CONCLUSIONS

Acanthosis nigricans is a non-invasive and reliable sign of the underlying MetS and increased serum chemerin levels among individuals with obesity.

Systemic Inflammation, Oxidative Stress and Cardiovascular Health in Children and Adolescents: A Systematic Review

Recent studies indicate that cerebrovascular diseases and processes of atherosclerosis originate in the childhood era and are largely influenced by chronic inflammation. Some features of vascular dysfunction in adulthood may even be programmed prenatally via genetic influences and an unfavorable intrauterine milieu. Oxidative stress, defined by an imbalance between the production and generation of reactive oxygen species (ROS) in cells and tissues and the capability of an organism to scavenge these molecules via antioxidant mechanisms, has been linked to adverse cardiovascular health in adults, yet has not been systematically reviewed in the pediatric population. We performed a systematic search as per the PRISMA guidelines in PubMed/Medline and Cochrane Reviews and detected, in total, 1228 potentially eligible pediatric articles on systemic inflammation, oxidative stress, antioxidant use, cardiovascular disease and endothelial dysfunction. The abstracts and full-text manuscripts of these were screened for inclusion and exclusion criteria, and a total of 160 articles were included. The results indicate that systemic inflammation and oxidative stress influence cardiovascular health in many chronic pediatric conditions, including hypertension, obesity, diabetes mellitus types 1 and 2, chronic kidney disease, hyperlipidemia and obstructive sleep apnea. Exercise and diet may diminish ROS formation and enhance the total serum antioxidant capacity. Antioxidant supplementation may, in selected conditions, contribute to the diminution of the oxidative state and improve endothelial function; yet, in many areas, studies provide unsatisfactory results.

Chemerin as Potential Biomarker in Pediatric Diseases: A PRISMA-Compliant Study

Adipose tissue is the main source of adipokines and therefore serves not only as a storage organ, but also has an endocrine effect. Chemerin, produced mainly in adipocytes and liver, is a natural ligand for chemokine-like receptor 1 (CMKLR1), G-protein-coupled receptor 1 (GPR1) and C-C motif chemokine receptor-like 2 (CCRL2), which have been identified in many tissues and organs. The role of this protein is an active area of research, and recent analyses suggest that chemerin contributes to angiogenesis, adipogenesis, glucose homeostasis and energy metabolism. Many studies confirm that this molecule is associated with obesity in both children and adults. We conducted a systematic review of data from published studies evaluating chemerin in children with various disease entities. We searched PubMed to identify eligible studies published prior to February 2022. A total of 36 studies were selected for analysis after a detailed investigation, which was intended to leave only the research studies. Moreover, chemerin seems to play an important role in the development of cardiovascular and digestive diseases. The purpose of this review was to describe the latest advances in knowledge of the role of chemerin in the pathogenesis of various diseases from studies in pediatric patients. The mechanisms underlying the function of chemerin in various diseases in children are still being investigated, and growing evidence suggests that this adipokine may be a potential prognostic biomarker for a wide range of diseases.

Pro- and anti-inflammatory adipokines are associated with cardiometabolic risk markers in Brazilian schoolchildren

Pro- and anti-inflammatory adipokines have been regarded as potential markers of obesity and cardiometabolic comorbidities. However, few studies have evaluated this association in children. We aimed to evaluate the relationship between adipokine concentrations and cardiometabolic risk markers in Brazilian schoolchildren. This was a cross-sectional study with 378 children aged 8-9 years from Viçosa, Minas Gerais, Brazil. We measured adipokines (leptin, retinol-binding protein 4, adiponectin, and chemerin) and cardiometabolic risk markers (fasting glucose, HOMA-IR, lipid profile, and blood pressure). Cardiometabolic risk markers were compared by quintiles of adipokines with linear regression adjusted for potential confounders. Leptin was positively associated with diastolic blood pressure (P = 0.03) and HOMA-IR (P = 0.01), and retinol-binding protein 4 was positively associated with total cholesterol (P = 0.04). Each standard deviation of leptin and retinol-binding protein 4 was associated to, respectively, a 0.1 (95%CI: 0.1; 0.2), 0.3 (95%CI: 0.1; 0.6), and 2.5 (95%CI: 0.1; 4.9) units increase in diastolic blood pressure, HOMA-IR, and total cholesterol. Adiponectin was negatively associated with diastolic blood pressure (P = 0.01) and HOMA-IR (P = 0.01), and chemerin was negatively associated with glucose (P = 0.001). Each standard deviation of adiponectin and chemerin was associated to, respectively, a -0.1 (95%CI: -0.2; -0.1), -0.2 (95%CI: -0.3; -0.1), and -1.2 (95%CI: -1.9; -0.5) units decrease in diastolic blood pressure, HOMA-IR, and glucose.Conclusion: Pro- and anti-inflammatory adipokines were positively and negatively associated with cardiometabolic risk markers, respectively, among schoolchildren, indicating this relationship may be identified at earlier ages. What is Known: • Although leptin, retinol-binding protein 4, and adiponectin are well-known adipokines, a consensus regarding their relationship with cardiometabolic risk markers, especially in schoolchildren, has not yet been reached. • Chemerin is an adipokine that has been studied recently. Yet, due to its dependence on the target cell type, its functions are still a controversial topic. What is New: • Leptin was positively associated with diastolic blood pressure and HOMA-IR, and retinol-binding protein 4 was positively associated with total cholesterol. • Adiponectin was negatively associated with diastolic blood pressure and HOMA-IR, and chemerin was negatively associated with glucose.

Adipo-specific chemerin knockout alters the metabolomic profile of adipose tissue under normal and high-fat diet conditions: Application of an untargeted liquid chromatography-tandem mass spectrometry metabolomics method

To explore the metabolic effect of chemerin, adipose-specific chemerin knockout (adipo-chemerin^-/- ) male mice were established and fed with 5-week normal diet (ND) or high-fat diet (HFD), and then the glycolipid metabolism index was measured and epididymal adipose tissue metabolomics detected using untargeted LC-tandem mass spectrometry (LC-MS/MS). Under HFD, adipo-chemerin^-/- mice showed improved glycolipid metabolism (decreased total cholesterol, low-density lipoprotein-cholesterol, insulin and Homeostasis Model Assessment of Insulin Resistance) compared with flox (control) mice. Furthermore, orthogonal partial least squares-discriminant analysis score plots identified separation of metabolites between adipo-chemerin^-/- mice and flox mice fed ND and HFD. Under HFD, 28 metabolites were significantly enhanced in adipo-chemerin^-/- mice, and pathway enrichment analysis suggested strong relationship of the differential metabolites with arginine and proline metabolism, phenylalanine metabolism, and phenylalanine, tyrosine and tryptophan biosynthesis, which were directly or indirectly related to lipid metabolism, inflammation and oxidative stress. Under ND, taurine was increased in adipo-chemerin^-/- mice, resulting in taurine and hypotaurine metabolism and primary bile acid biosynthesis. In conclusion, the improved effect of chemerin knockdown on the glycolipid metabolism of HFD-feeding male mice might be associated with the increases in differential metabolites and metabolic pathways involved in lipid metabolism, inflammation and oxidative stress, which provided insights into the mechanism of chemerin from a metabolomics aspect.

Effects of probiotic and synbiotic supplementation on insulin resistance in women with polycystic ovary syndrome: a meta-analysis

Objective

This meta-analysis evaluated the effect of probiotics and synbiotics on insulin resistance in patients with polycystic ovary syndrome (PCOS).

Methods

A systematic search was performed to identify all relevant publications listed on the electronic databases (PubMed®, Web of Science, Embase® and China National Knowledge Infrastructure) between inception and 30 October 2020. All statistical analyses were performed on randomized controlled trials (RCTs) using RevMan version 5.3 software provided by the Cochrane Collaboration.

Results

A total of 486 patients from seven RCTs were included in the meta-analysis. Probiotic and synbiotic supplementation appeared to improve levels of homeostatic model assessment of insulin resistance (mean difference = –0.37; 95% confidence interval –0.69, –0.05) and serum insulin (standardized mean difference = –0.66; 95% confidence interval –1.19, –0.12). The results failed to show any influence of probiotic and synbiotic supplementation on body mass index, waist circumference, hip circumference and fasting blood sugar.

Conclusions

Probiotics and synbiotics appear to have a partially beneficial effect on indices of insulin resistance in patients with PCOS.

Association between Toxoplasma gondii infection and metabolic syndrome in obese adolescents: A possible immune-metabolic link

Background Toxoplasmosis as a global disease is considered as a triggering factor responsible for development of several clinical diseases. However, Toxoplasma gondii (T. gondii) is an understudied parasite of potential interest in obesity research. The current study aimed to explore the role of latent T. gondii infection in the pathogenesis of metabolic syndrome (MetS) in obese adolescents through studying the relationship between serum interferon-gamma [IFN-γ] and serum chemerin in context of MetS components. Methods Eighty-three obese adolescents were serologically screened for T. gondii-IgG antibodies and compared to 35 age-matched healthy T. gondii-seronegative controls. Participants were evaluated for anthropometric measurements, total-fat mass [FM], trunk-FM, serum lipid profile, IFN-γ, and chemerin levels. Homeostatic Model Assessment of insulin resistance (HOMA-IR) was calculated. Results The prevalence of MetS was significantly higher within obese T. gondii-seropositive group compared to obese T. gondii-seronegative group (P = 0.033). Seropositive obese MetS group displayed significantly higher trunk-FM, HOMA-IR, chemerin, and IFN-γ compared to seronegative obese MetS group. Serum chemerin and IFN-γ were strongly correlated (P < 0.001) and were positively correlated with BMI, WC, total-FM, trunk-FM, HOMA-IR, cholesterol, triglycerides and negatively correlated with HDLC. HOMA-IR was a common predictor for serum chemerin (P = 0.030) and IFN-γ (P < 0.001). Conclusions The study results suggest that T. gondii infection may exert an immune-metabolic effect that may have a potential role in the development of MetS among obese adolescents.

Association of chemerin gene promoter methylation in maternal blood and breast milk during gestational diabetes

The intrauterine environment and early-life nutrition are regulated by maternal biomarkers in the blood and breast milk. We aimed to explore epigenetic modifications that may contribute to differential chemerin expression in maternal plasma, colostrum, and breast milk and find its association with fetal cord blood and infant weight at 6 weeks postpartum. Thirty-three gestational diabetes mellitus (GDM) mothers and 33 normoglycemic mothers (NGT) were recruited. Two maternal blood samples (28th week of gestation and 6 weeks postpartum), cord blood, colostrum, and mature milk were collected. Methylation-specific polymerase chain reaction and enzyme-linked immunosorbent assay were conducted. The weight of the babies was measured at birth and 6 weeks postpartum. Serum chemerin levels at the 28th gestational week and 6 weeks postpartum were significantly lower for the NGT group as compared to the GDM group; (P < 0.05). Higher colostrum chemerin concentrations were observed in the GDM group and remained elevated in mature milk as compared to NGT (P < 0.05). Colostrum and breast milk chemerin levels showed an independent association with infant weight at 6 weeks postpartum (r = 0.270; P = 0.034) (r = 0.464; P < 0.001). Forty percent GDM mothers expressed unmethylated chemerin reflecting increased chemerin concentration in the maternal blood. This pattern was also observed in newborn cord blood where 52% of samples showed unmethylated chemerin in contrast to none in babies born to normoglycemic mothers. The results of this study highlight the critical importance of altered chemerin regulation in gestational diabetic mothers and its effect during early life period and suggest a possible role in contributing to childhood obesity.

The role of chemerin in the pathogenesis of cholelithiasis in children and adolescents

BACKGROUND AND AIM

Adipokines and hepatokines are proteins secreted by adipose tissue and the liver. To date, the levels of adipokines and hepatokines in cholelithiasis have only been evaluated in studies in adult patients. The purpose of our research was to assess the levels of circulating adipokines: chemerin, vaspin, progranulin, retinol-binding protein 4 (RBP-4) and hepatokine: fibroblast growth factor 21 (FGF-21) and to compare their concentrations in paediatric patients with and without cholelithiasis.

METHODS

The prospective study included 54 children and adolescents diagnosed with gallstones and 26 controls. Fasting serum levels of adipokines and hepatokine were determined by enzyme-linked immunosorbent assays.

RESULTS

The serum levels of chemerin, FGF-21 and RBP-4 were significantly higher in children and adolescents with gallstones compared to the control group. Elevated levels of triglycerides, RBP-4, and a homeostatic model for assessing insulin resistance (HOMA-IR) were observed in overweight or obese patients compared to patients with normal weight and cholelithiasis. Chemerin concentrations were increased in the normal-weight children and adolescents with cholelithiasis compared to the control group. Children and adolescents with gallstones and abnormal weight had significantly higher levels of chemerin, FGF-21 and RBP-4 than healthy controls.

CONCLUSION

Elevated serum chemerin levels were significantly higher in non-obese patients with cholelithiasis than in non-obese controls, suggesting a potential role of chemerin in the development of cholelithiasis in children and adolescents.

The dietary inflammatory index is associated with anti- and pro-inflammatory adipokines in Brazilian schoolchildren

PURPOSE

To investigate the relationship of Children's Dietary Inflammatory Index (C-DII™) scores with body fat distribution and serum adipokines in Brazilian schoolchildren.

METHODS

This population-based cross-sectional study enrolled 378 schoolchildren aged 8 and 9 years from Viçosa, Minas Gerais, Brazil. Food consumption was assessed using three 24-h dietary recalls from which C-DII scores were calculated. Serum adipokines [adiponectin, leptin, retinal-binding protein 4 (RBP4), and chemerin] were analyzed in blood samples. Sociodemographic characteristics and sedentary behavior were assessed using a semi-structured questionnaire. Total, truncal, android and gynoid body fat were evaluated by dual-energy X-ray absorptiometry (DXA). We compared the distributions of adiposity measures and serum adipokines by C-DII categories with linear regression, adjusting for potential confounders.

RESULTS

The mean sample C-DII was 0.59 ± 0.94 and ranged from - 2.16 to + 2.75. The C-DII was not associated with central and total body fat. However, the C-DII was modestly inversely associated with adiponectin and RBP4, and modestly directly associated with chemerin. These results remained significant after adjusting for body fat. Every 1 SD of C-DII was related, respectively, to a - 0.8 (- 1.5, - 0.03) and to a - 0.1 (- 0.2, - 0.05) units lower mean of adiponectin and RBP4, and to 7.2 (0.3, 14.1) units higher of chemerin.

CONCLUSION

Higher C-DII score was modestly inversely and directly associated with anti- and pro-inflammatory adipokines, respectively, in Brazilian children. The development of public health policies is needed to promote healthy eating habits during childhood to prevent the early onset of systemic inflammation and ill health effects later in life.

Special Issue: 2019 Consortium for Trans-Pyrenean Investigations on Obesity and Diabetes

This Special Issue of the Journal of Physiology and Biochemistry contains 6 contributions that exemplify the advances obtained by the mini-network entitled "Consortium of Trans-Pyrenean Investigations on Obesity and Diabetes" (CTPIOD), which is on its 16th year of existence. This scientific community, essentially based in France and Spain, but also open to participants coming from all over the world, is focusing its attention on the prevention and the novel treatments of obesity, diabetes, and other non-communicable diseases. Accordingly, this special issue will cover some nutritional, pharmacologic, and genetic aspects of the current knowledge of metabolic diseases. Some of these papers emerge from the lectures of the 16th Conference on Trans-Pyrenean Investigations in Obesity and Diabetes, held in Soria (Spain) in June 2019.

Higher Lipopolysaccharide Binding Protein and Chemerin Concentrations Were Associated with Metabolic Syndrome Features in Pediatric Subjects with Abdominal Obesity during a Lifestyle Intervention

Background: Elevated circulating plasma levels of both lipopolysaccharide-binding protein (LBP) and chemerin are reported in patients with obesity, but few studies are available on lifestyle intervention programs. We investigated the association of both LBP and chemerin plasma levels with metabolic syndrome (MetS) outcomes in a lifestyle intervention in children and adolescents with abdominal obesity Methods: Twenty-nine patients enrolled in a randomized controlled trial were selected. The lifestyle intervention with a 2-month intensive phase and a subsequent 10-month follow-up consisted of a moderate calorie-restricted diet, recommendations to increase physical activity levels, and nutritional education. Results: Weight loss was accompanied by a significant reduction in MetS prevalence (−43%; p = 0.009). Chemerin (p = 0.029) and LBP (p = 0.033) plasma levels were significantly reduced at 2 months and 12 months, respectively. At the end of intervention, MetS components were associated with both LBP (p = 0.017) and chemerin (p < 0.001) plasma levels. Conclusions: We describe for the first time a reduction in both LBP and chemerin plasma levels and its association with MetS risk factors after a lifestyle intervention program in children and adolescents with abdominal obesity. Therefore, LBP and chemerin plasma levels could be used as biomarkers for the progression of cardiovascular risk in pediatric populations.

Serum Calprotectin and Chemerin Concentrations as Markers of Low-Grade Inflammation in Prepubertal Children with Obesity

In adults, obesity is associated with chronic low-grade inflammation, which may cause long-term adverse health consequences. We evaluated whether obesity in prepubertal children also generates this kind of inflammation and whether calprotectin and chemerin may be useful markers for early detection of such inflammation in this group of children. The study population included 83 children aged 2 to 10 years; 62 with obesity and without components of metabolic syndrome and 21 healthy controls with normal body weight. White blood cell (WBC) count, concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), calprotectin, and chemerin were determined in peripheral blood. Our study showed that in the group with obesity, serum concentrations of calprotectin and chemerin, as well as CRP were significantly higher as compared with the controls. We found a significant positive correlation between serum chemerin concentrations and BMI z-score (r = 0.33, p < 0.01) in children with obesity. Chemerin concentration was also positively correlated with CRP level (r = 0.36, p < 0.01) in the whole group of children. These findings suggest that obesity may generate chronic low-grade inflammation as early as in the prepubertal period which can be indicated by significantly higher serum concentrations of calprotectin and chemerin. Calprotectin and especially chemerin seem to be promising indicators of this type of inflammation in children with obesity, but the correlation between these markers requires further research.

Characteristic-Grouped Adiposity Indicators for Identifying Metabolic Syndrome in Adolescents: Develop and Valid Risk Screening Tools Using Dual Population

A simple, robust, and characterized adiposity indicator may be appropriate to be used as a risk screening tool for identifying metabolic syndrome (MetS) in adolescents. This study used dual adolescent populations to develop and validate efficient adiposity indicators from 12 characterized candidates for identifying MetS that may occur during the transition from adolescence to young adulthood. Data from the adolescent Nutrition and Health Survey in Taiwan (n = 1920, 12–18 years) and the multilevel Risk Profiles for adolescent MetS study (n = 2727, 12–16 years) were respectively used as training and validation datasets. The diagnostic criteria defined by the International Diabetes Federation for adolescents (IDF-adoMetS) and the Joint Interim Statement for adults (JIS-AdMetS) were employed to evaluate MetS. In the training dataset, principal component analysis converted 12 interrelated obesity indices into bodyfat-, lipid-, and body-shape-enhanced groups, with the first two characteristic-groups having a higher discriminatory capability in identifying IDF-adoMetS and JIS-AdMetS. In the validation dataset, abdominal volume index (AVI) among girls and waist circumference (WC) among boys were respectively validated to have a higher Youden’s index (0.740–0.816 and 0.798–0.884) in identifying the two MetS. Every 7.4 and 4.3 positive tests of AVI (cutoff = 13.96) had an accurate IDF-adoMetS and JIS-AdMetS, respectively, and every 32.4 total tests of WC (cutoff = 90.5 cm) had a correct identification for the two MetS. This study stresses the discriminatory capability of bodyfat- and lipid-enhanced adiposity indicators for identifying MetS. AVI and WC were, respectively, supported as a risk screening tool for identifying female and male MetS as adolescents transition to adulthood.

Chemerin enhances the adhesion and migration of human endothelial progenitor cells and increases lipid accumulation in mice with atherosclerosis

Background

The role of adipokines in the development of atherosclerosis (AS) has received increasing attention in recent years. This study aimed to explore the effects of chemerin on the functions of human endothelial progenitor cells (EPCs) and to investigate its role in lipid accumulation in ApoE-knockout (ApoE−/−) mice.

Methods

EPCs were cultured and treated with chemerin together with the specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB 203580 in a time- and dose-dependent manner. Changes in migration, adhesion, proliferation and the apoptosis rate of EPCs were detected. ApoE−/− mice with high-fat diet-induced AS were treated with chemerin with or without SB 203580. Weights were recorded, lipid indicators were detected, and tissues sections were stained.

Results

The data showed that chemerin enhanced the adhesion and migration abilities of EPCs, and reduced the apoptosis ratio and that this effect might be mediated through the p38 MAPK pathway. Additionally, chemerin increased the instability of plaques. Compared with the control group and the inhibitor group, ApoE−/− mice treated with chemerin protein had more serious arterial stenosis, higher lipid contents in plaques and decreased collagen. Lipid accumulation in the liver and kidney and inflammation in the hepatic portal area were enhanced by treatment with chemerin, and the size of adipocytes also increased after chemerin treatment. In conclusion, chemerin can enhance the adhesion and migration abilities of human EPCs and reduce the apoptosis ratio. In animals, chemerin can increase lipid accumulation in atherosclerotic plaques and exacerbate plaques instability. At the same time, chemerin can cause abnormal lipid accumulation in the livers and kidneys of model animals. After specifically blocking the p38 MAPK pathway, the effect of chemerin was reduced.

Conclusions

In conclusion, this study showed that chemerin enhances the adhesion and migration abilities of EPCs and increases the instability of plaques and abnormal lipid accumulation in ApoE−/− mice. Furthermore, these effects might be mediated through the p38 MAPK pathway.

Diabetes and Obesity-Cumulative or Complementary Effects On Adipokines, Inflammation, and Insulin Resistance

Background: Diabetes and obesity are increasingly significant public health issues. The aim of this study was to evaluate the relationship between adipocytokines (leptin, ghrelin, and chemerin), inflammation (sVCAM1—soluble vascular adhesion molecule 1, sICAM1—soluble intercellular adhesion molecule 1), and insulin resistance in the presence of obesity and diabetes mellitus. Methods: 88 subjects, with a mean age of 61.96 ± 10.15 years, 75% of whom were women, were evaluated (in order to consider different associations between obesity and diabetes, subjects were categorized into four groups). Results: Overall, we found significant correlations between sICAM1-sVCAM1 rho = 0.426 and ghrelin-chemerin rho = −0.224. In the obesity + diabetes group, leptin correlated with sICAM1 rho = 0.786, and sVCAM1 negatively with glycemia/insulin rho = −0.85. Significant differences were found between the groups regarding sVCAM1 (p = 0.0134), leptin (p = 0.0265) and all insulin resistance scores, with differences influenced by the subjects’ gender. In conclusion, although there are currently many unknown aspects of the release and the role of various adipokines, in particular chemerin, its implication in early glucose metabolism dysregulation disorders seems very likely.

A Screened GPR1 Peptide Exerts Antitumor Effects on Triple-Negative Breast Cancer

The adipokine chemerin has been considered an important regulator of tumor immune surveillance. Chemerin recruits leukocytes through the receptor CMKLR1 to improve clinical outcomes of tumors and overall patient survival, but the role of GPR1 in tumors has not been widely investigated. Here, we found that GPR1 expression is elevated in breast cancer-especially triple-negative breast cancer (TNBC) tissues and cell lines. Herein, we screened a phage display peptide library to identify LRH7-G5, a peptide antagonist that blocks chemerin/GPR1 signaling. This peptide performed as an anticancer agent to suppress the proliferation of the TNBC cell lines MDA-MB-231 and HCC1937 but has little effect on T47D cells. LRH7-G5 treatment significantly blocked tumor growth in a TNBC cell-bearing orthotopic mouse model. Last, our results showed that this peptide's antitumor role is mediated through the PI3K/AKT signaling pathway. In conclusion, these data collectively suggest that the chemerin receptor GPR1 is a novel target for controlling TNBC progression and establish peptide LRH7-G5 as a new therapeutic agent for suppressing TNBC tumor growth.

The methylation status of the chemerin promoter region located from - 252 to + 258 bp regulates constitutive but not acute-phase cytokine-inducible chemerin expression levels

Chemerin is a chemoattractant protein with adipokine properties encoded by the retinoic acid receptor responder 2 (RARRES2) gene. It has gained more attention in the past few years due to its multilevel impact on metabolism and immune responses. However, mechanisms controlling the constitutive and regulated expression of RARRES2 in a variety of cell types remain obscure. To our knowledge, this report is the first to show that DNA methylation plays an important role in the cell-specific expression of RARRES2 in adipocytes, hepatocytes, and B lymphocytes. Using luciferase reporter assays, we determined the proximal fragment of the RARRES2 gene promoter, located from - 252 to + 258 bp, to be a key regulator of transcription. Moreover, we showed that chemerin expression is regulated in murine adipocytes by acute-phase cytokines, interleukin 1β and oncostatin M. In contrast with adipocytes, these cytokines exerted a weak, if any, response in mouse hepatocytes, suggesting that the effects of IL-1β and OSM on chemerin expression is specific to fat tissue. Together, our findings highlight previously uncharacterized mediators and mechanisms that control chemerin expression.

Exploring Therapeutic Targets to Reverse or Prevent the Transition from Metabolically Healthy to Unhealthy Obesity

The prevalence of obesity and obesity-related metabolic comorbidities are rapidly increasing worldwide, placing a huge economic burden on health systems. Excessive nutrient supply combined with reduced physical exercise results in positive energy balance that promotes adipose tissue expansion. However, the metabolic response and pattern of fat accumulation is variable, depending on the individual’s genetic and acquired susceptibility factors. Some develop metabolically healthy obesity (MHO) and are resistant to obesity-associated metabolic diseases for some time, whereas others readily develop metabolically unhealthy obesity (MUO). An unhealthy response to excess fat accumulation could be due to susceptibility intrinsic factors (e.g., increased likelihood of dedifferentiation and/or inflammation), or by pathogenic drivers extrinsic to the adipose tissue (e.g., hyperinsulinemia), or a combination of both. This review outlines the major transcriptional factors and genes associated with adipogenesis and regulation of adipose tissue homeostasis and describes which of these are disrupted in MUO compared to MHO individuals. It also examines the potential role of pathogenic insulin hypersecretion as an extrinsic factor capable of driving the changes in adipose tissue which cause transition from MHO to MUO. On this basis, therapeutic approaches currently available and emerging to prevent and reverse the transition from MHO to MUO transition are reviewed.

Effects of different obesity-related adipokines on the occurrence of obstructive sleep apnea

Obstructive sleep apnea (OSA), characterized by recurrent episodes of apnea during sleep and daytime sleepiness, seriously affects human health and may lead to systemic organ dysfunction. The pathogenesis of OSA is complex and still uncertain, but multiple surveys have shown that obesity is an important factor, and the incidence of OSA in people with obesity is as high as 30%. Adipokines are a group of proteins secreted from adipocytes, which are dysregulated in obesity and may contribute to OSA. Here, we review the most important and representative research results regarding the correlation between obesity-related adipokines including leptin, adiponectin, omentin-1, chemerin, and resistin and OSA in the past 5 years, provide an overview of these key adipokines, and analyze possible intrinsic mechanisms and influencing factors. The existing research shows that OSA is associated with an increase in the serum levels of leptin, chemerin, and resistin and a decrease in the levels of adiponectin and omentin-1; the findings presented here can be used to monitor the development of OSA and obesity, prevent future comorbidities, and identify risk factors for cardiovascular and other diseases, while different adipokines can be linked to OSA through different pathways such as insulin resistance, intermittent hypoxia, and inflammation, among others. We hope our review leads to a deeper and more comprehensive understanding of OSA based on the relevant literature, which will also provide directions for future clinical research.

Chemerin predicts carotid intima-media thickening in severe obesity

BACKGROUND AND AIMS

Chemerin is an adipokine with an emerging role in the crosstalk between adipose tissue and immune system. It is overexpressed in severe obesity, affects adipogenesis and glucose homeostasis and it correlates with early vascular damage. The aim of this study is to investigate the correlation between circulating levels of chemerin and early vascular damage in subjects with severe obesity, before and after laparoscopic sleeve gastrectomy (LSG).

METHODS

Fifty-six obese subjects eligible for LSG were enrolled in the study. The following parameters were evaluated: body mass index (BMI), glycemia, insulinemia, glycated haemoglobin, lipid profile, plasma chemerin levels and carotid intima-media thickness (cIMT). Fifty-four subjects were evaluated 1 year after the intervention.

RESULTS

Univariate analysis showed a direct and significant correlation between chemerin and waist circumference, insulin resistance, glycated haemoglobin and cIMT. Chemerin was a better predictor of intima-media thickening than waist circumference and glycated haemoglobin at the ROC curve analysis, with a cut-off value for chemerin of 140 ng/mL. The reduction of chemerin is independently associated with the reduction of cIMT and the improvement of insulin sensitivity after LSG.

CONCLUSION

Chemerin is involved in the development and progression of early vascular damage and insulin resistance in subjects with severe obesity, and in their healing after bariatric surgery. Chemerin could also have a role in the assessment of cardiovascular risk in subjects with severe obesity.

Chemerin in immune response and gastrointestinal pathophysiology

Chemerin is a multifunctional protein involved among others in adipogenesis, angiogenesis and lipid as well as glucose metabolism. Chemerin is an essential factor in promotion of chemotaxis of numerous immune cell types and plays an important role in several pathophysiologic conditions. Chemerin receptors are present on monocytes/macrophages, T cells, natural killer and dendritic cells as well as neutrophils. However, the role of chemerin and chemerin receptors in immune response and gastrointestinal diseases is still poorly understood. Accumulating, clinical and experimental studies observed disturbation of chemerin and chemerin receptors in a number of disorders including Barrett's esophagus, esophageal cancer, gastric cancer, hepatic dysfunction, irritable bowel syndrome, inflammatory bowel disease and colorectal cancer. Moreover, chemerin and chemerin receptors have been shown to regulate proliferation, migration and invasion of gastrointestinal and immune cells as well as cancer-associated fibroblasts. In this review we present the current state of knowledge about the contribution of chemerin to immune response and gastrointestinal disorders.

Elevated chemerin induces insulin resistance in human granulosa-lutein cells from polycystic ovary syndrome patients

The insulin resistance (IR) of ovarian granulosa cells from polycystic ovary syndrome (PCOS) aggravates the abnormalities in steroidogenesis and anovulation, and chemerin is an adipokine involved in regulating adipogenesis and glucose homeostasis. The role and underlying mechanism of chemerin in developing IR of the granulosa cells from PCOS remain unclear. Plasma, follicular fluid, and human granulosa-lutein cells (hGLs) were collected from non-PCOS and patients with PCOS with or without IR. The chemerin levels were elevated in both follicular fluid and hGL samples from patients with PCOS with IR, and the hGLs from patients with PCOS with IR showed decreased insulin sensitivity and impaired glucose uptake capacity. Moreover, treatment of chemerin attenuated insulin-stimulated glucose uptake by decreasing phosphorylation of insulin receptor substrate (IRS)1/2 Tyr612, phosphorylation of protein kinase B Ser473, and membrane translocation of glucose transporter type 4 through increasing Ser307 phosphorylation of IRS1 in cultured hGLs. These effects could be abolished by small interfering RNA-mediated knockdown of chemokine-like receptor 1. Furthermore, insulin induced the expression of chemerin in hGLs. Our findings demonstrate a novel role of chemerin in the metabolic dysfunction of PCOS, which suggested that chemerin and its receptor can be further implicated as potential therapeutic targets in the future treatment of PCOS.-Li, X., Zhu, Q., Wang, W., Qi, J., He, Y., Wang, Y., Lu, Y., Wu, H., Ding, Y., Sun, Y. Elevated chemerin induces insulin resistance in human granulosa-lutein cells from polycystic ovary syndrome patients.

Serum adipokines and metabolic indicators in girls with Turner syndrome

The aim of this study was to discuss the association between serum adipokines levels and metabolic indicators in girls with Turner syndrome.

Effects of curcumin supplementation on markers of inflammation and oxidative stress among healthy overweight and obese girl adolescents: A randomized placebo-controlled clinical trial

INTRODUCTION

It is well known that there is a strong linkage between obesity, systemic low-grade inflammation, and oxidative stress in the pediatric population. Possible strategies that might control obesity and its relevant problems in this crucial group are of utmost importance. Therefore, the aim of this study was to evaluate the effects of curcumin supplements on inflammation, oxidative stress, and chemerin levels in adolescent girls.

METHODS

Totally, 60 overweight and obese adolescent girls were randomly assigned to either placebo or intervention group in a randomized placebo-controlled parallel trial design. Adolescents consumed one 500-mg curcumin or placebo per day along with a slight weight loss diet for 10 weeks. High-sensitive C-reactive protein (hs-CRP), interleukin 6 (IL-6), total antioxidant capacity (TAC), malondialdehyde (MDA), chemerin levels, and anthropometric measurements were assessed at the beginning and end of the trial.

RESULTS

Curcumin supplementation had a significant effect on IL-6 levels and oxidative stress markers including TAC and MDA in crude model. After controlling the effects of confounders, curcumin supplementation had a substantial effect on inflammation (hs-CRP and IL-6) and oxidative stress (TAC) marker of adolescents.

DISCUSSION

Ten weeks of curcumin supplementation had beneficial effects on inflammation and oxidative stress markers among postpubescent overweight and obese girl adolescents.

Serum Chemerin Levels Correlate With Determinants of Metabolic Syndrome in Obese Children and Adolescents

Objectives

This study aimed to investigate serum chemerin concentrations in obese children and adolescents and to investigate the associations of chemerin with body mass index (BMI), lipid levels, and insulin sensitivity.

Methods

Forty-eight obese and 40 nonobese Chinese children and adolescents were included in the study. BMI and levels of chemerin, lipids, glucose, and insulin were measured following an overnight fast. The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and BMI standard deviation score (BMI-SDS) were determined for all participants.

Results

Serum chemerin levels were found to be significantly higher in obese children and adolescents than in control group members (94.83 ± 5.99 ng/mL vs 56.43 ± 4.16 ng/mL, P < .001). There were significant correlations between chemerin and age, BMI, BMI-SDS, total triglyceride (TG) levels, insulin levels, and HOMA-IR. After controlling for age, we found that chemerin levels were also significantly correlated with BMI-SDS (r =+ 0.284, P = .008) and HOMA-IR (r =+ 0.241, P = .034). In a stepwise multiple regression analysis, we observed only BMI-SDS to be an important determinant of chemerin level.

Conclusions

In our sample of Chinese children and adolescents, chemerin levels were significantly higher in the obese group than in the control group. Chemerin levels were positively correlated with BMI-SDS and HOMA-IR and negatively correlated with age. We thus believe that further study is necessary to investigate the risk of metabolic abnormalities in young obese children and adolescents.

The serum biomarker chemerin promotes tumorigenesis and metastasis in oral squamous cell carcinoma

Chemerin, which is encoded by retinoic acid receptor responder 2 (RARRES2), has been found to be related to malignant tumours, but its role in the development of oral squamous cell carcinoma (OSCC) is largely unexplored. In the present study, a higher serum level of chemerin was evident in patients with OSCC than in healthy individuals, and this high level of chemerin significantly decreased after tumour resection. In addition, high chemerin levels were positively associated with advanced tumour stage and lymph node metastasis. The expression levels of chemerin and Chemerin Receptor 23 (ChemR23) were positively correlated with the migration and invasion of OSCC cell lines. Recombinant chemerin (R-chemerin) enhanced the in vitro migration, invasion and proliferation of OSCC cells in a concentration-dependent manner, and short hairpin RNAs (shRNAs) targeting RARRES2 decreased chemerin expression and inhibited OSCC cell metastasis and proliferation both in vitro and in vivo Additionally, R-chemerin activated manganese superoxide dismutase (SOD2) and increased the amount of intracellular hydrogen peroxide (H₂O₂), leading to a significant decrease in E-cadherin expression and dramatic increase in the expression of phosphorylated ERK1/2 (p-ERK1/2), Slug, Vimentin and N-cadherin, but shRNAs targeting RARRES2 reversed these effects. Moreover, knockdown of ChemR23 with small interfering RNAs (siRNA) significantly inhibited chemerin-induced OSCC cell migration/invasion and SOD2 activity. Our results revealed that chemerin is a novel biomarker for OSCC. Chemerin/ChemR23 promotes tumorigenesis and metastasis in OSCC and may be a new therapeutic target for OSCC.