Interleukin-1beta induces the novel adipokine chemerin in adipocytes in vitro

The mind-skin connection: A narrative review exploring the link between inflammatory skin diseases and psychological stress

Inflammatory skin diseases are known to negatively impact patient psychology, with individuals experiencing higher rates of stress and subsequent diminished quality of life, as well as mental health issues including anxiety and depression. Moreover, increased psychological stress has been found to exacerbate existing inflammatory skin diseases. The association between inflammatory skin diseases and psychological stress is a timely topic, and a framework to better understand the relationship between the two that integrates available literature is needed. In this narrative review article, we discuss potential neurobiological mechanisms behind psychological stress due to inflammatory skin diseases, focusing mainly on proinflammatory cytokines in the circulating system (the brain-gut-skin communications) and the default mode network in the brain. We also discuss potential descending pathways from the brain that lead to aggravation of inflammatory skin diseases due to psychological stress, including the central and peripheral hypothalamic-pituitary-adrenal axes, peripheral nerves and the skin barrier function.

Adipokines as an important link between hidradenitis suppurativa and obesity: a narrative review

Hidradenitis suppurativa (HS) is a chronic, recurrent, debilitating disorder of the pilosebaceous unit. Although its pathophysiology is not fully explained, inflammation seems to play an essential role in the development of HS. A link between obesity - often considered a state of chronic inflammation - and a higher prevalence of HS has been described. Nevertheless, the exact association is not well understood. Adipose tissue is a highly active endocrine organ that produces and secretes a variety of metabolically and immunologically active molecules called adipokines. The imbalances in concentrations of several adipokines in patients with HS have already been described. A shift towards the overproduction of proinflammatory adipokines (including leptin, resistin and visfatin) with the suppression of anti-inflammatory ones (adiponectin) has been noted. We conducted a review of the available data on adipokines in HS, concentrating on the described imbalances in adipokine concentrations, as well as possible implications in HS pathogenesis. Moreover, new, unstudied adipokines with possible implications in the development of HS are proposed.

A new predictor for prediabetes: Chemerin

Objective: It was aimed to investigate irisin and chemerin levels in prediabetic individuals and their value in predicting prediabetes. Method: Thirty-eight prediabetic patients aged 18-65 years (22 impaired fasting glucose (IFG), 10 impaired glucose tolerance (IGT), 6 patients with coexisting IFG and IGT) and thirty-five healthy volunteers were included in which was designed as a cross-sectional study. The basic demographic characteristics of all participants in the case and control groups were compared with the serum chemerin, irisin, creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), high-density lipoprotein (HDL-cholesterol), low-density lipoprotein (LDL-cholesterol), triglyceride (TG), free thyroxine (sT4), and thyroid-stimulating hormone (TSH) levels. Result: Serum chemerin level was found to be higher in the prediabetic group (p=0.03), while no significant difference was found for the irisin level between the two groups. In the multivariate logistic regression analysis, we showed that chemerin was an independent risk factor in predicting prediabetes. There was a positive correlation (p=0.01, r=0.279) between all participants' body mass index (BMI) and chemerin level and a negative correlation between irisin level and high-density lipoprotein cholesterol (HDL-C) level, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (p=0.04 r=-0.295, p=0.01 r=-0.407, respectively). Conclusion: Chemerin is a new generation chemokine that predicts prediabetes. Studies aimed at irisin and chemerin may provide important role to prevent the prediabetes to Type 2 diabetes progression.

Thromboinflammatory Processes at the Nexus of Metabolic Dysfunction and Prostate Cancer: The Emerging Role of Periprostatic Adipose Tissue

Simple Summary

As overweight and obesity increase among the population worldwide, a parallel increase in the number of individuals diagnosed with prostate cancer was observed. There appears to be a relationship between both diseases where the increase in the mass of fat tissue can lead to inflammation. Such a state of inflammation could produce many factors that increase the aggressiveness of prostate cancer, especially if this inflammation occurred in the fat stores adjacent to the prostate. Another important observation that links obesity, fat tissue inflammation, and prostate cancer is the increased production of blood clotting factors. In this article, we attempt to explain the role of these latter factors in the effect of increased body weight on the progression of prostate cancer and propose new ways of treatment that act by affecting how these clotting factors work.

Abstract

The increased global prevalence of metabolic disorders including obesity, insulin resistance, metabolic syndrome and diabetes is mirrored by an increased incidence of prostate cancer (PCa). Ample evidence suggests that these metabolic disorders, being characterized by adipose tissue (AT) expansion and inflammation, not only present as risk factors for the development of PCa, but also drive its increased aggressiveness, enhanced progression, and metastasis. Despite the emerging molecular mechanisms linking AT dysfunction to the various hallmarks of PCa, thromboinflammatory processes implicated in the crosstalk between these diseases have not been thoroughly investigated. This is of particular importance as both diseases present states of hypercoagulability. Accumulating evidence implicates tissue factor, thrombin, and active factor X as well as other players of the coagulation cascade in the pathophysiological processes driving cancer development and progression. In this regard, it becomes pivotal to elucidate the thromboinflammatory processes occurring in the periprostatic adipose tissue (PPAT), a fundamental microenvironmental niche of the prostate. Here, we highlight key findings linking thromboinflammation and the pleiotropic effects of coagulation factors and their inhibitors in metabolic diseases, PCa, and their crosstalk. We also propose several novel therapeutic targets and therapeutic interventions possibly modulating the interaction between these pathological states.

Circulating Chemerin and Its Kinetics May Be a Useful Diagnostic and Prognostic Biomarker in Critically Ill Patients with Sepsis: A Prospective Study

Chemerin, a novel adipokine, is a potent chemoattractant molecule with antimicrobial properties, implicated in immune responses. Our aim was to investigate circulating chemerin and its kinetics, early in sepsis in critically ill patients and its association with severity and prognosis. Serum chemerin was determined in a cohort of 102 critically ill patients with sepsis during the first 48 h from sepsis onset and one week later, and in 102 age- and gender-matched healthy controls. Patients were followed for 28 days and their outcomes were recorded. Circulating chemerin was significantly higher in septic patients at onset compared to controls (342.3 ± 108.1 vs. 200.8 ± 40.1 μg/L, p < 0.001). Chemerin decreased significantly from sepsis onset to one week later (342.3 ± 108.1 vs. 308.2 ± 108.5 μg/L, p < 0.001), but remained higher than in controls. Chemerin was higher in patients presenting with septic shock than those with sepsis (sepsis onset: 403.2 ± 89.9 vs. 299.7 ± 99.5 μg/L, p < 0.001; one week after: 374.9 ± 95.3 vs. 261.6 ± 91.9 μg/L, p < 0.001), and in nonsurvivors than survivors (sepsis onset: 427.2 ± 96.7 vs. 306.9 ± 92.1 μg/L, p < 0.001; one week after: 414.1 ± 94.5 vs. 264.2 ± 79.9 μg/L, p < 0.001). Moreover, patients with septic shock and nonsurvivors, presented a significantly lower absolute and relative decrease in chemerin one week after sepsis onset compared to baseline (p < 0.001). Based on ROC curve analyses, the diagnostic performance of chemerin (AUC 0.78, 95% CI 0.69–0.87) was similar to C-reactive protein (CRP) (AUC 0.78, 95% CI 0.68–0.87) in discriminating sepsis severity. However, increased chemerin at sepsis onset and one week later was an independent predictor of 28-day mortality (sepsis onset: HR 3.58, 95% CI 1.48–8.65, p = 0.005; one week after: HR 10.01, 95% CI 4.32–23.20, p < 0.001). Finally, serum chemerin exhibited significant correlations with the severity scores, white blood cells, lactate, CRP and procalcitonin, as well as with biomarkers of glucose homeostasis, but not with cytokines and soluble urokinase-type plasminogen activator receptor (suPAR). Circulating chemerin is increased early in sepsis and its kinetics may have diagnostic and prognostic value in critically ill patients. Further studies are needed to shed light on the role of chemerin in sepsis.

Role of chemerin in the control of glucose homeostasis

Chemerin is an adipokine produced by the white adipose tissue and other tissues, which plays various roles in the pathogenesis of inflammatory and metabolic diseases in multiple organs. The present review aims at gathering scientific evidence reported in the last ten years, concerning the relationship of chemerin with alterations of glycaemic control, such as insulin resistance, type 2 diabetes and gestational diabetes in humans. Although the vast majority of the studies have shown a positive correlation between the chemerin level and a bad glycaemic control, a general consensus has not been reached. The reported results come from case-control and observational longitudinal studies, thereby limiting their interpretation. In fact, it cannot be stated whether insulin resistance and diabetes lead to an increase in chemerin levels or, on the contrary, if high levels of chemerin contribute to an impaired glycaemic control. Elevated levels of circulating chemerin are also associated with gestational diabetes mellitus. Chemerin gene polymorphisms could be proposed as mediators of glucose-related diseases. Nevertheless, to date very little is known about their implication in glucose metabolism. With regard to the mechanisms of action, chemerin impairs insulin cascade signaling by acting on several proteins of this cascade and by inducing inflammation.

Chemerin - exploring a versatile adipokine

Chemerin is a small chemotactic protein and a key player in initiating the early immune response. As an adipokine, chemerin is also involved in energy homeostasis and the regulation of reproductive functions. Secreted as inactive prochemerin, it relies on proteolytic activation by serine proteases to exert biological activity. Chemerin binds to three distinct G protein-coupled receptors (GPCR), namely chemokine-like receptor 1 (CMKLR1, recently named chemerin₁), G protein-coupled receptor 1 (GPR1, recently named chemerin₂), and CC-motif chemokine receptor-like 2 (CCRL2). Only CMKLR1 displays conventional G protein signaling, while GPR1 only recruits arrestin in response to ligand stimulation, and no CCRL2-mediated signaling events have been described to date. However, GPR1 undergoes constitutive endocytosis, making this receptor perfectly adapted as decoy receptor. Here, we discuss expression pattern, activation, and receptor binding of chemerin. Moreover, we review the current literature regarding the involvement of chemerin in cancer and several obesity-related diseases, as well as recent developments in therapeutic targeting of the chemerin system.

Chemerin contributes to inflammatory responses and suppresses osteogenic differentiation in chronic periodontitis

BACKGROUND

Chronic periodontitis (CP) is a common disease of oral cavity, and approximately 35% of adults suffered from CP. Therefore, its underlying mechanism needs to be explored for new therapeutic approaches. Chemerin as a multifunctional adipokine, is found to be highly expressed in the gingival crevicular fluid (GCF), gingival tissues and the plasma of periodontitis patients. Thus, we aimed to uncover the underlying mechanism of chemerin in CP.

METHODS

36 CP patients and 25 healthy volunteers were enrolled. Periodontal ligament stem cells (PDLSCs) were isolated from CP patients and healthy ones respectively. Then normal PDLSCs or PDLSCs-differentiated osteoblasts were treated with different doses of recombinant human chemerin.

RESULTS

Chemerin and inflammatory cytokines, including interleukin-1β, interleukin-6 and tumor necrosis factor-α, were higher in the GCF and serum of CP patients than healthy ones. Moreover, chemerin was positively correlated with these three inflammatory cytokines respectively in CP patients. PDLSCs isolated from CP patients had higher expressions of chemerin and these cytokines than the ones isolated from normal individuals. Furthermore, chemerin dose-dependently increased inflammatory responses and inhibited osteogenic differentiation of PDLSCs.

CONCLUSION

Chemerin accelerated inflammatory responses and suppressed osteogenic differentiation of PDLSCs, thus chemerin might sever as a therapeutic target of CP.

The Association of Serum Circulating Neuropeptide Q and Chemerin Levels with Cardiometabolic Risk Factors among Patients with Metabolic Syndrome

The potential involvement of neuropeptide Q (NPQ) and chemerin (CHEM) in metabolic disorders is yet to be fully elucidated. The aim of this study was to evaluate serum concentrations of NPQ and CHEM and to establish their relationship with cardiometabolic risk factors among individuals with metabolic syndrome. A total of 66 patients with metabolic syndrome (MetS) and 83 healthy volunteers (non-MetS) underwent biochemical, blood pressure, and anthropometric measurements. The concentration of NPQ in the MetS group was significantly lower (0.47 (0.34 ; 0.54) vs. 0.52 (0.43 ; 0.60) ng/mL, p = 0.015) than in non-MetS, while there were no differences in CHEM level. In the entire study population, we observed several negative correlations between NPQ concentration and waist-hip ratio (WHR), visceral adipose tissue, diastolic blood pressure (DBP), triglycerides (TG) along with a positive correlation with high-density lipoprotein (HDL), total muscle mass, and CHEM. Moreover, a negative correlation was observed in the MetS group between NPQ and glycemia. CHEM showed no significant correlations with cardiometabolic risk factors in the study population. In a multiple regression model, the total muscle mass proved to be an independent factor determining NPQ concentration in the population (p < 0.00000001, R²_adj = 28.6%). NPQ seems to protect against metabolic disorders correlated with obesity. Thus, it is worth considering NPQ level as a candidate protective biomarker of metabolic syndrome complications.

Adipokines in dental pulp: physiological, pathological, and potential therapeutic roles

BACKGROUND

Hundreds of adipokines have been identified, and their extensive range of endocrine functions-regulating distant organs such as oral tissues-and local autocrine/paracrine roles have been studied. In dentistry, however, adipokines are poorly known proteins in the dental pulp; few of them have been studied despite their large number. This study reviews recent advances in the investigation of dental-pulp adipokines, with an emphasis on their roles in inflammatory processes and their potential therapeutic applications.

HIGHLIGHTS

The most recently identified adipokines in dental pulp include leptin, adiponectin, resistin, ghrelin, oncostatin, chemerin, and visfatin. They have numerous physiological and pathological functions in the pulp tissue: they are closely related to pulp inflammatory mechanisms and actively participate in cell differentiation, mineralization, angiogenesis, and immune-system modulation.

CONCLUSION

Adipokines have potential clinical applications in regenerative endodontics and as biomarkers or targets for the pharmacological management of inflammatory and degenerative processes in dental pulp. A promising direction for the development of new therapies may be the use of agonists/antagonists to modulate the expression of the most studied adipokines.

Novel Cardioprotective Effect of L-Carnitine on Obese Diabetic Mice: Regulation of Chemerin and CMKLRI Expression in Heart and Adipose Tissues

Fundamentos

A L-carnitina (LC) tem muitos efeitos benéficos em animais diabéticos e humanos, mas seu efeito regulatório sobre a quemerina como uma citocina inflamatória e seu receptor no estado diabético são desconhecidos.

Objetivos

O presente estudo teve como objetivo investigar o efeito regulatório da LC na expressão do receptor semelhante ao de quimiocina 1 e quemerina (CMKLRI) em tecidos adiposo e cardíaco de camundongos diabéticos.

Métodos

Sessenta camundongos NMARI foram divididos em quatro grupos, incluindo controle, diabético, diabético + suplementação com LC e controle + suplementação com LC. O diabetes foi induzido pela alimentação dos animais com dieta hipercalórica por 5 semanas e injeção de estreptozotocina. Os animais foram tratados com 300 mg/kg de LC por 28 dias. Nos dias 7, 14 e 28 após o tratamento, os níveis de mRNA e proteína da quemerina e CMKLRI nos tecidos cardíacos e adiposos de animais foram determinados utilizando análise por qPCR e ELISA. Os índices de resistência à insulina também foram medidos em todos os grupos experimentais. A diferença com p<0,05 foi considerada significativa.

Resultados

A expressão de quemerina e CMKLRI aumentou nos tecidos cardíaco e adiposo de camundongos diabéticos nos dias 14 e 28 após a indução do diabetes, concomitantemente com a incidência de resistência à insulina e níveis aumentados de quemerina circulante (p<0,05). O tratamento com LC causou uma diminuição significativa na expressão de ambos os genes nos tecidos estudados e redução dos sintomas de resistência à insulina e dos níveis séricos de quemerina (p<0,05).

Conclusão

Os resultados sugerem que o tratamento com LC pode diminuir a expressão de quemerina e CKLR1 em tecidos cardíacos e adiposos de animais experimentais obesos e diabéticos.

Determinants of elevated chemerin as a novel biomarker of immunometabolism: data from a large population-based cohort

OBJECTIVE

Chemerin is a novel inflammatory biomarker suggested to play a role in the development of metabolic disorders, providing new avenues for treatment and prevention. Little is known about the factors that predispose elevated chemerin concentrations. We therefore aimed to explore a range of lifestyle-associated, dietary, and metabolic factors as potential determinants of elevated chemerin concentrations in asymptomatic adults.

DESIGN

We used cross-sectional data from a random subsample of 2433 participants (1494 women and 939 men) aged 42-58 years of the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort.

METHODS

Random forest regression (RFR) was applied to explore the relative importance of 32 variables as statistical predictors of elevated chemerin concentrations overall and by sex. Multivariable-adjusted linear regression was applied to evaluate associations between selected predictors and chemerin concentrations.

RESULTS

Results from RFR suggested BMI, waist circumference, C-reactive protein, fatty liver index, and estimated glomerular filtration rate as the strongest predictors of chemerin concentrations. Additional predictors included sleeping duration, alcohol, red and processed meat, fruits, sugar-sweetened beverages (SSB), vegetables, dairy, and refined grains. Collectively, these factors explained 32.9% variation of circulating chemerin. Multivariable-adjusted analyses revealed linear associations of elevated chemerin with metabolic parameters, obesity, longer sleep, higher intakes of red meat and SSB, and lower intakes of dairy.

CONCLUSIONS

These findings come in support of the role of chemerin as a biomarker characterizing inflammatory and metabolic phenotypes in asymptomatic adults. Modifiable dietary and lifestyle-associated determinants of elevated chemerin concentrations require further evaluation in a prospective study setting.

Development of metabolic dysfunction in mice lacking chemerin

Chemerin, an adipocyte-secreted adipokine, is hypothesized to participate in energy homeostasis and glucoregulation. However, the physiologic effect of endogenous chemerin on glucose metabolism is unclear. The present studies tested the hypotheses that chemerin deficiency alters whole-body glucose homeostasis following switches to high-fat diet. Adult, male chemerin knockout and C57BL/6J control wild type mice were studied. During the following 4 weeks, chow- or high-fat diet maintained chemerin knockout mice showed elevated fasting glucose levels and glucose intolerance as well as insulin intolerance. Chemerin deficiency impaired adaptation to glucose and insulin challenge, leading to increased glucose levels. Moreover, the mRNA and protein levels of GLUT4 and PGC-1α expression in both skeletal muscle and adipose tissue were significantly decreased in chemerin knockout mice relative to the wild type, respectively. Taken together, the results support the hypotheses that chemerin helps adapt glucose metabolism to changes in dietary fat and modulates glucose consumption in mice by activation of PGC-1α/GLUT4 axis. Chemerin may play a significant role in elevation of glucose uptake and insulin sensitivity to promote glucose clearance.

Serum chemerin levels: A potential biomarker of joint inflammation in women with rheumatoid arthritis

Background

Chemerin has a potential role in perpetuating inflammation in autoimmune diseases. Nevertheless, to date, there is no conclusive information on whether high chemerin levels increase the severity of rheumatoid arthritis (RA). Therefore, this study evaluated whether serum chemerin is a biomarker of disease activity in RA patients.

Methods

Study design: cross-sectional. The assessment included clinical and laboratory characteristics, body mass index (BMI) and fat mass. The severity of the disease activity was identified according to the DAS28-CRP index as follows: A) RA with a DAS28-CRP≤2.9 (remission/mild activity) and B) RA with a DAS28-CRP>2.9 (moderate/severe activity). Serum chemerin concentrations were measured by ELISA, and ≥103 ng/mL was considered a high level. Logistic regression analysis was applied to determine whether high chemerin levels were associated with disease activity in RA after adjusting for confounders. Multiple regression analysis was performed to identify variables associated with chemerin levels.

Results

Of 210 RA patients, 89 (42%) subjects had moderate/severe disease activity and had higher serum chemerin levels than patients with low disease activity or remission (86 ± 34 vs 73± 27; p = 0.003). Serum chemerin correlated with the number of swollen joints (r = 0.15; p = 0.03), DAS28-CRP (r = 0.22; p = 0.002), and C-reactive protein levels (r = 0.14; p = 0.04), but no correlation was observed with BMI and fat mass. In the adjusted logistic regression analysis, high chemerin levels (≥103 ng/mL) were associated with an increased risk of moderate/severe disease activity (OR: 2.76, 95% CI 1.35–5.62; p = 0.005). In the multiple regression analysis, after adjusting for potential confounders, serum chemerin levels were associated with higher DAS28-CRP (p = 0.002).

Conclusions

Higher chemerin levels increased the risk of moderate and severe disease activity in RA. These results support the role of chemerin as a marker of inflammation in RA. Follow-up studies will identify if maintaining low chemerin levels can be used as a therapeutic target.

Chemerin activity in selected pathological states of human body - A systematic review

Recent studies have revealed that fatty tissue, so far considered an energy storage organ, is also the source of many substances called adipokines, including chemerin which plays many important functions in the body. Chemerin stimulates adipocytes maturation and differentiation, as well as acts as a chemoattractant, which stimulates innate and acquired immunity. This adipokine participates in the early stages of acute inflammation as well as its suppression by reacting with the CMKLR1 receptor. In various diseases associated with inflammatory processes, the level of chemerin in the serum increases. It is also considered a marker for benign and malignant tumors. Explanation of the pathomechanisms involving this adipokine is of a high importance and may contribute to the development of new possibilities in the treatment of many diseases. The article presents the latest information on the role of chemerin in various pathological states, particularly in psoriasis.

Serum Chemerin Concentration Is Associated with Proinflammatory Status in Chronic Coronary Syndrome

Background: Chemerin is an adipokine and a chemoattractant for leukocytes. Increased chemerin levels were observed in patients with coronary artery disease (CAD). We investigated associations between chemerin and biochemical measurements or body composition in CAD patients. Methods: In the study, we included patients with stable CAD who had undergone percutaneous coronary intervention (PCI) in the past. All patients had routine blood tests, and their insulin and chemerin serum levels were routinely measured. Body composition was assessed with the DEXA method. Results: The study group comprised 163 patients (mean age 59.8 ± years, 26% of females, n = 43). There was no significant difference in serum chemerin concentrations between patients with diabetes and the remaining ones: 306.8 ± 121 vs. 274.15 ± 109 pg/mL, p = 0.1. Chemerin correlated positively with the white blood cell (WBC) count, the neutrophil to lymphocyte ratio, hsCRP, all fractions of cholesterol, triglycerides, platelet count, fasting insulin, and c-peptide. Chemerin levels were also correlated with total fat mass but only in a subgroup with normal glucose metabolism. Conclusion: In patients with CAD, serum chemerin levels are correlated with inflammation markers, insulin resistance, and an unfavorable lipid profile. Correlation with fat mass is dependent on glucose metabolism status. Depending on the presence of diabetes/prediabetes, the mechanisms regulating chemerin secretion may be different.

Synergistic effects of high-intensity interval training (HIIT) and intake of nettle on serum levels of chemerin and beta cells function in type 2 diabetic rats

OBJECTIVES

This animal study aimed to demonstrate the synergistic effect of high-intensity interval training (HIIT) and alcoholic extract of nettle on serum chemerin and beta cells function in type 2 diabetic male rats.

METHODS

Thirty-two STZ-induced diabetic male Wistar rats were randomly divided into four groups including the control group, the supplemented group with 200 mg/day of nettle, the training group with five sessions per week of HIIT, and the group with combined nettle and HITT intervention. Body weight, lipid profile, beta cells function, and chemerin level were assessed after eight weeks of the intervention.

RESULTS

The values of chemerin significantly decreased in combined HIIT and nettle intervention group compared to the control group (p=0.001). The levels of glucose and insulin decreased significantly in nettle group, exercise group, and combined HIIT and nettle group (p=0.001).

CONCLUSIONS

The present study found that intense interval exercise with the consumption of alcoholic extract of nettle can affect the performance of beta cells, glucose, and insulin. Future human studies are warranted.

Chemerin causes lipid metabolic imbalance and induces passive lipid accumulation in human hepatoma cell line via the receptor GPR1

AIMS

Chemerin is abundant in patients with high body mass index and metabolic syndrome possibly due to its activation in adipogenesis and glucose intolerance. It has reported that sera chemerin is positively associated with fatty liver with little known underlying mechanisms. Our aim is to study the role of chemerin in hepatic lipid metabolism.

MAIN METHODS

Oil Red O staining and TG quantitative assay were used to detect intracellular lipid accumulation. PCR, QPCR and western blot were applied to measure lipid metabolism-related genes, CMKLR1, GPR1 and inflammation marker genes. Luciferase reporter assay was employed to uncover the down-regulation of proximate promoter activities of CMKLR1 and GPR1 by SREBP1c. Antibody neutralization assay was used to address the effects of chemerin on hepatic lipid synthesis.

KEY FINDINGS

Over-expression of chemerin led to passive lipid accumulation, in human hepatoma cell line HepG2. The disable form of chemerin (chemerin 21-158) and active chemerin (chemerin 21-157) performed strongly effects on lipid metabolism in HepG2 cells. Heterologous expression of CMKLR1 or G-protein coupled receptor1 (GPR1) played similar roles in hepatocyte lipid metabolism as chemerin. Chemerin exerted its effects on lipid metabolism via GPR1 in HepG2 cells. Furthermore, free fatty acids and high concentration insulin inhibited chemerin expression. Consistently, the key lipogenic transcription factor Sterol regulatory element binding protein 1c suppressed chemerin mRNA expression and proximate promoter activities of CMKLR1 and GPR1.

SIGNIFICANCE

It implied the existence of negative feed-back regulation and further confirmed the involvement of chemerin in hepatic lipid metabolism.

Chemerin in inflammatory diseases

Obesity is associated with a series of health problems. Adipocytes are a huge repository of energy as well as an important source of many adipokines. In obesity, adipocytes are dysfunctional with excessive production and secretion of pro-inflammatory adipokines, such as tumor necrosis factor α (TNF-α), leptin, and chemerin. Recent studies have revealed that chemerin plays an important role in modulating physiologic as well as pathophysiologic processes. For example, chemerin stimulates maturation and differentiation of pre-adipocytes, acts as a chemoattractant and facilitates innate and acquired immunity. Furthermore, chemerin participates in the early stage of acute inflammation by reacting with the ChemR23 receptor. In various inflammatory diseases, the serum chemerin is significantly increased. Additionally, chemerin is also considered as an important biomarker for benign and malignant tumors. Thus, elucidating the pathologic mechanisms of chemerin action may facilitate the development of new therapeutic modalities to treat diverse inflammatory diseases. In this review, we summarize current knowledge of chemerin and its role as an important regulator in modulating various inflammatory diseases. Mechanisms underlying chemerin function in diverse diseases are explored to better understand its biochemistry and mechanisms of action.

Role of Kallikrein 7 in Body Weight and Fat Mass Regulation

Increased plasma and adipose tissue protease activity is observed in patients with type 2 diabetes and obesity. It has been proposed that specific proteases contribute to the link between obesity, adipose tissue inflammation and metabolic diseases. We have recently shown that ablation of the serine protease kallikrein-related peptidase 7 (Klk7) specifically in adipose tissue preserves systemic insulin sensitivity and protects mice from obesity-related AT inflammation. Here, we investigated whether whole body Klk7 knockout (Klk7^-/-) mice develop a phenotype distinct from that caused by reduced Klk7 expression in adipose tissue. Compared to littermate controls, Klk7^-/- mice gain less body weight and fat mass both under chow and high fat diet (HFD) feeding, are hyper-responsive to exogenous insulin and exhibit preserved adipose tissue function due to adipocyte hyperplasia and lower inflammation. Klk7^-/- mice exhibit increased adipose tissue thermogenesis, which is not related to altered thyroid function. These data strengthen our recently proposed role of Klk7 in the regulation of body weight, energy metabolism, and obesity-associated adipose tissue dysfunction. The protective effects of Klk7 deficiency in obesity are likely linked to a significant limitation of adipocyte hypertrophy. In conclusion, our data indicate potential application of specific KLK7 inhibitors to regulate KLK7 activity in the development of obesity and counteract obesity-associated inflammation and metabolic diseases.

Concurrent metformin and silibinin therapy in diabetes: assessments in zebrafish (Danio rerio) animal model

Objective

In this study, zebrafish was used as a biological model to induce type 2 diabetes mellitus through glucose. Then, the effect of metformin and silibinin combination was examined on elevated blood glucose, intestinal tissues, liver enzymes, and TNF-α, IFN-γ, INL1β genes as inflammation marker genes.

Methods

The liver enzymes (AST, ALT, and ALP) derived from fish viscera homogenate supernatants were assayed in an auto-analyzer. The expression of target genes was quantified on RNA extracted from the tails by an in-house RT-PCR method, with fine intestine tissue staining performed by hematoxylin and eosin protocol (H&E).

Result

In the glucose-free treatments, metformin and silymarin decreased the levels of AST, ALT, and ALP enzymes in the blood. The combination of these two drugs had also a significant role in reducing glucose levels. The body weight increased significantly in the control group which was affected by glucose concentration, with the lowest body weight gain observed in the metformin group. The expression of INL-1β gene was significantly enhanced in the control group and the highest IFN-γ expression was observed in both control groups with glucose (G + CTRL) and without glucose (G-CTRL) (p < 0.05). The lowest level of TNF-α gene expression was observed in the control + glucose group (G + CTRL) (p < 0.05). Diabetic state causes weak absorption whereby the fish body demands to increase absorption level by enhancing the amount of acidic goblet cells thereby acidifying the environment in the gastric tracts.

Conclusion

Collectively, this study indicated that treatment with metformin and Silibinin could improve metabolic-mediated performances by reducing the expression of inflammatory genes and blood glucose, modulating liver enzymes, and ameliorating the intestinal inflammation in type 2 diabetic zebrafish model.

Adipokines and Inflammation: Focus on Cardiovascular Diseases

It is well established that adipose tissue, apart from its energy storage function, acts as an endocrine organ that produces and secretes a number of bioactive substances, including hormones commonly known as adipokines. Obesity is a major risk factor for the development of cardiovascular diseases, mainly due to a low grade of inflammation and the excessive fat accumulation produced in this state. The adipose tissue dysfunction in obesity leads to an aberrant release of adipokines, some of them with direct cardiovascular and inflammatory regulatory functions. Inflammation is a common link between obesity and cardiovascular diseases, so this review will summarise the role of the main adipokines implicated in the regulation of the inflammatory processes occurring under the scenario of cardiovascular diseases.

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.

Semaphorin 3 C is a Novel Adipokine Representing Exercise-Induced Improvements of Metabolism in Metabolically Healthy Obese Young Males

This study investigated the endurance exercise-induced changes in lesser known adipokines (visfatin, chemerin, apelin, semaphorin 3 C) related to obesity and metabolism, and their correlations with the changes in the parameters of obesity and glucose homeostasis. Forty metabolically healthy obese young males were randomly assigned to control group (C, n = 12) or exercise group (Ex, n = 28). The subjects in Ex participated in a 8-week supervised endurance exercise training program, comprised of four sessions of treadmill running at 65–70% of VO_2max per week. Serum levels of visfatin, chemerin, apelin, and semaphorin 3 C were significantly decreased in Ex. At baseline, apelin and semaphorin 3 C appeared to be correlated with obesity measures, including body mass index, % total fat and trunk fat, and waist circumference. Exercise-induced changes in these obesity measures significantly correlated with the changes in chemerin and semaphorin 3 C. Basal chemerin, apelin and semaphorin 3 C correlated with glucose homeostasis parameters, including fasting plasma glucose, fasting plasma insulin, homeostasis model assessment of insulin resistance and β-cell function, and quantitative insulin-sensitivity check index to different extents. Furthermore, the changes in apelin and semaphorin 3 C well predicted the improvements in glycemic parameters. We suggest that semaphorin 3 C is a novel adipokine involved in pathophysiology of obesity and metabolism, and that it is a biomarker representing an exercise-induced improvement in metabolically healthy obese young males.

Association of selected adipokines with metabolic syndrome and cardio-metabolic risk factors in young males

The study aimed to investigate association of circulating leptin, adiponectin, chemerin, and omentin-1 with metabolic syndrome (MetS) and cardio-metabolic risk factors in youths. Thirty eight young males were enrolled. Participants underwent anthropometric and blood pressure measures, and fasting blood sampling. Plasma leptin, adiponectin, chemerin, omentin-1 and insulin were measured by ELISA methods. Multiple linear regression models, adjusting for age, MetS traits, C-reactive protein (CRP) and homeostasis model assessment of insulin resistance (HOMA-IR), were applied to determine correlates for each adipokine. Eleven participants meet criteria of MetS. These individuals had higher leptin and chemerin and lower adiponectin plasma concentrations than those without MetS. Plasma leptin and chemerin were positively related, and adiponectin and omentin-1 were inversely related to cardio-metabolic traits. In multivariate models, predictors of leptin were age (β, 0.20, P = 0.01), abdominal obesity (β, 0.24, P = 0.06), raised blood pressure (β, 0.40, P = 0.01), raised triglycerides (β, 0.19, P = 0.01) and CRP (β, 0.31, P = 0.01). Chemerin was associated with abdominal obesity (β, 0.33, P = 0.09) and CRP (β, 0.29, P = 0.04), and adiponectin was associated with raised triglycerides (β, -0.26, P = 0.05), decreased HDL-C (β, -0.28, P = 0.06) and CRP (β, -0.48, P = 0.01). HOMA-IR (β, -0.39, P = 0.09) was the only predictor for omentin. MetS is associated with an altered plasma adipokines profile, with increased leptin and chemerin and decreased adiponectin circulating levels. These findings suggest a beneficial potential of adiponectin and omentin, but a detrimental potential of leptin and chemerin. Further research is needed to lighten the role of adipose tissue-derived adipokines in cardio-metabolic health.

Chemerin facilitates intervertebral disc degeneration via TLR4 and CMKLR1 and activation of NF-kB signaling pathway

Now days, obesity is a major risk factor for intervertebral disc degeneration (IDD). However, adipokine, such as chemerin is a novel cytokine, which is secreted by adipose tissue, and are thought to be played major roles in various degenerative diseases. Obese individuals are known to have high concentration of serum chemerin. Our purpose was to study whether chemerin acts as a biochemical relationship between obesity, and IDD. In this study, we found that the expression level of chemerin was significantly increased in the human degenerated nucleus pulposus (NP) tissues, and had higher level in the obese people than the normal people. Chemerin significantly increased the inflammatory mediator level, contributing to ECM degradation in nucleus pulposus cells (NPCs). Furthermore, chemerin overexpression aggravates the puncture-induced IVDD progression in rats, while knockdown CMKLR1 reverses IVDD progression. Chemerin activates the NF-kB signaling pathway via its receptors CMKLR1, and TLR4 to release inflammatory mediators, which cause matrix degradation, and cell aging. These findings generally provide novel evidence supporting the causative role of obesity in IDD, which is essentially important to literally develop novel preventative or generally therapeutic treatment in the disc degenerative disorders.

Chemerin: A Potential Regulator of Inflammation and Metabolism for Chronic Obstructive Pulmonary Disease and Pulmonary Rehabilitation

Chronic obstructive pulmonary disease (COPD) features chronic inflammatory reactions of both intra- and extrapulmonary nature. Moreover, COPD is associated with abnormal glucose and lipid metabolism in patients, which influences the prognosis and chronicity of this disease. Abnormal glucose and lipid metabolism are also closely related to inflammation processes. Further insights into the interactions of inflammation and glucose and lipid metabolism might therefore inspire novel therapeutic interventions to promote lung rehabilitation. Chemerin, as a recently discovered adipokine, has been shown to play a role in inflammatory response and glucose and lipid metabolism in many diseases (including COPD). Chemerin recruits inflammatory cells to sites of inflammation during the early stages of COPD, leading to endothelial barrier dysfunction, early vascular remodeling, and angiogenesis. Moreover, it supports the recruitment of antigen-presenting cells that guide immune cells as part of the body's inflammatory responses. Chemerin also regulates metabolism via activation of its cognate receptors. Glucose homeostasis is affected via effects on insulin secretion and sensitivity, and lipid metabolism is changed by increased transformation of preadipocytes to mature adipocytes through chemerin-binding receptors. Controlling chemerin signaling may be a promising approach to improve various aspects of COPD-related dysfunction. Importantly, several studies indicate that chemerin expression in vivo is influenced by exercise. Although available evidence is still limited, therapeutic alterations of chemerin activity may be a promising target of therapeutic approaches aimed at the rehabilitation of COPD patients based on exercises. In conclusion, chemerin plays an essential role in COPD, especially in the inflammatory responses and metabolism, and has a potential to become a target for, and a biomarker of, curative mechanisms underlying exercise-mediated lung rehabilitation.

Analysis of serum chemerin concentrations in psoriatic patients in relation to metabolic abnormalities

Introduction

Recent data depict psoriasis as a systemic disease with many comorbidities, especially metabolic syndrome and cardiovascular diseases. Chemerin, an adipokine secreted by adipose tissue cells, may prove to be an important link between psoriasis and its comorbidities.

Aim

Assessment of serum concentrations of chemerin in patients with psoriasis and the healthy control group as well as evaluation of a possible correlation between adipokine concentrations and selected psoriasis severity indices and metabolic syndrome components.

Material and methods

One hundred and two patients with diagnosed psoriasis and 40 healthy volunteers were enrolled in the study. In all subjects, serum chemerin concentrations and selected metabolic syndrome components including lipid and glucose levels were determined. Psoriasis severity was assessed using the PASI and BSA indices.

Results

A higher concentration of chemerin was demonstrated in the group of psoriasis patients compared to the control group (p < 0.05). A positive correlation between chemerin concentration and C-reactive protein concentration (p = 0.001), body mass index (p = 0.031) and triglyceride concentration (p = 0.043) was found. An inverse correlation with high-density lipoprotein cholesterol concentrations (p = 0.015) was also noted. Significantly higher concentrations of chemerin were observed in psoriatic patients with elevated low-density lipoptotein (LDL) cholesterol levels in comparison with patients with normal LDL values (p = 0.032). Chemerin concentrations were also significantly higher in patients with both psoriasis and elevated glucose levels compared to patients with normal blood glucose values (p = 0.043).

Conclusions

The results obtained suggest a possible role of chemerin as an adipokine linking psoriasis with metabolic syndrome.

Effects of moderate-intensity continuous training and high-intensity interval training on serum levels of Resistin, Chemerin and liver enzymes in Streptozotocin-Nicotinamide induced Type-2 diabetic rats

BACKGROUND

The aim of this study was to investigate the effects of of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) in serum resistin, chemerin, insulin, liver enzymes and lipid profiles levels.

METHODS

24 Wistar rats with mean weight of 200 ± 50 g were randomly assigned to non-diabetic rats (ND-Cnt), diabetic control (D-Cnt), diabetic training groups. The diabetic training group received 10 weeks of HIIT (D-HIIT) and MICT (D-MICT) following the induction of diabetes. Evaluating resistin, chemerin and insulin hormones levels through ELISA. FBS and liver enzyme levels were measured by biochemical kits.

RESULTS

HIIT and MICT resulted in a significant decrease in resistin, chemerin and fasting blood glucose (P < 0.05) compared to the D-Cnt (P < 0.05). Serum values of FBS, lipid profiles and liver enzyme (P < 0.05) decreased significantly more in the HIIT group compared with the MICT group (P < 0.05). As well as, the resistin level positively and significantly associated with values of ALT and chemerin level positively and significantly associated with values of ALT, ALP and AST in all rat (P < 0.05).

CONCLUSION

In general, our findings demonstrated that the HIIT leads to better improvements in serum liver enzyme levels, FBS and lipid profiles compared to MICT. HIIT therefore appears to be an important time-efficient treatment for treatment with type 2 diabetes rats.

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.

Inflammation Markers in Type 2 Diabetes and the Metabolic Syndrome in the Pediatric Population

PURPOSE OF REVIEW

Chronic inflammation, adipokines, and hepatokines have been identified as basis of insulin resistance and β cell failure in animal models. We present our current knowledge concerning the potential relationship between these cytokines, inflammation, metabolic syndrome (MetS), and type 2 diabetes mellitus (T2DM) in the pediatric population.

RECENT FINDINGS

Pro-inflammatory cytokines related to insulin resistance and MetS in children are tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, interferon gamma, pigment epithelium-derived factor, chemerin, vaspin, and fetuin A. Anti-inflammatory cytokines associated with insulin resistance and MetS in children are leptin, adiponectin, omentin, fibroblast growth factor (FGF)-21, osteocalcin, and irisin. These anti-inflammatory cytokines are decreased (adiponectin, omentin, and osteocalcin) or increased (leptin, FGF-21, and irisin) in obesity suggesting a resistance state. TNF-α, fetuin A, and FGF-21 are altered in obese children with T2DM suggesting an involvement in β cell failure. These cytokines, adipokines, and hepatokines may be able to predict development of MetS and T2DM and have a potential therapeutic target ameliorating insulin resistance.

Type 2 diabetes - An autoinflammatory disease driven by metabolic stress

Type 2 diabetes has traditionally been viewed as a metabolic disorder characterised by chronic high glucose levels, insulin resistance, and declining insulin secretion from the pancreas. Modern lifestyle, with abundant nutrient supply and reduced physical activity, has resulted in dramatic increases in the rates of obesity-associated disease conditions, including diabetes. The associated excess of nutrients induces a state of systemic low-grade chronic inflammation that results from production and secretion of inflammatory mediators from the expanded pool of activated adipocytes. Here, we review the mechanisms by which obesity induces adipose tissue dysregulation, detailing the roles of adipose tissue secreted factors and their action upon other cells and tissues central to glucose homeostasis and type 2 diabetes. Furthermore, given the emerging importance of adipokines, cytokines and chemokines in disease progression, we suggest that type 2 diabetes should now be viewed as an autoinflammatory disease, albeit one that is driven by metabolic dysregulation.

Chemerin: a multifaceted adipokine involved in metabolic disorders

Metabolic syndrome is a global public health problem and predisposes individuals to obesity, diabetes and cardiovascular disease. Although the underlying mechanisms remain to be elucidated, accumulating evidence has uncovered a critical role of adipokines. Chemerin, encoded by the gene Rarres2, is a newly discovered adipokine involved in inflammation, adipogenesis, angiogenesis and energy metabolism. In humans, local and circulating levels of chemerin are positively correlated with BMI and obesity-related biomarkers. In this review, we discuss both peripheral and central roles of chemerin in regulating body metabolism. In general, chemerin is upregulated in obese and diabetic animals. Previous studies by gain or loss of function show an association of chemerin with adipogenesis, glucose homeostasis, food intake and body weight. In the brain, the hypothalamus integrates peripheral afferent signals including adipokines to regulate appetite and energy homeostasis. Chemerin increases food intake in seasonal animals by acting on hypothalamic stem cells, the tanycytes. In peripheral tissues, chemerin increases cell expansion, inflammation and angiogenesis in adipose tissue, collectively resulting in adiposity. While chemerin signalling enhances insulin secretion from pancreatic islets, contradictory results have been reported on how chemerin links to obesity and insulin resistance. Given the association of chemerin with obesity comorbidities in humans, advances in translational research targeting chemerin are expected to mitigate metabolic disorders. Together, the exciting findings gathered in the last decade clearly indicate a crucial multifaceted role for chemerin in the regulation of energy balance, making it a promising candidate for urgently needed pharmacological treatment strategies for obesity.

Chemerin, Inflammatory, and Nitrooxidative Stress Marker Changes Six Months after Sleeve Gastrectomy

Background

Chemerin is a chemokine known to be increased in morbidly obese (MO) patients and correlated with markers of inflammation and nitrooxidative stress. We aimed to evaluate the changes of serum chemerin six months after laparoscopic sleeve gastrectomy (SG) and to asses if these changes are accompanied by variations of inflammatory and nitrooxidative stress markers.

Material and Methods

We investigated the levels of chemerin, high-sensitive C-reactive protein (hsCRP), tumor necrosis factor alpha (TNF-α), nitrite and nitrate (NOx), total oxidant status (TOS), total antioxidant response (TAR), and oxidative stress index (OSI) in a group of 24 MO patients submitted to SG before and six months after surgery. The MO group was compared with 20 controls.

Results

hsCRP (p < 0.001), NOx (p < 0.001), TOS (p < 0.001), TAR (p = 0.007), and OSI (p = 0.001) were significantly different between the two groups. Six months after surgery, we noticed significant changes (42.28% decrease) of hsCRP (p = 0.044) and OSI (p = 0.041) (31.81% decrease), while no significant changes were observed for chemerin (p = 0.605), TNF-α (p = 0.287), NOx (p = 0.137), TOS (p = 0.158), and TAR (p = 0.563).

Conclusions

Our study showed no significant changes of chemerin, and except for hsCRP and OSI, no other inflammatory and nitrooxidative stress markers changed six months after surgery.

Serum levels of adipokines and cytokines in psoriasis patients: a systematic review and meta-analysis

Purpose

To evaluate the association of serum levels of adipokines and cytokines with psoriasis.

Materials and Methods

A comprehensive literature search was performed in PubMed, ScienceDirect and Web of Science for the available relevant studies published before December 1, 2016. Differences in serum marker levels between patients and controls were pooled as standardized mean differences (SMDs) with 95% confidence interval to combine the effect estimations. We also conducted stratified analysis, meta-regression analysis and sensitivity analysis.

Results

Sixty-three studies containing 2876 psoriasis patients and 2237 healthy controls were included in this meta-analysis. The pooled serum levels of TNF-α, IFN-γ, IL-2, IL-6, IL-8, IL-18, IL-22, chemerin, lipocalin-2, resistin, sE-selectin, fibrinogen and C3 were higher in psoriasis patients compared with healthy controls (all P < 0.05). In contrast, adiponectin levels were lower. Serum levels of IL-1β, IL-4, IL-10, IL-12, IL-17, IL-21, IL-23, visfatin and omentin were not significantly different between psoriasis patients and controls (all P > 0.05). However, increased serum levels of IL-17 correlated with psoriasis in men. For other biomarkers, age, gender and psoriasis area and severity index did not explain the differences in effect size between the studies.

Conclusions

Serum levels of TNF-α, IFN-γ, IL-2, IL-6, IL-8, IL-18, IL-22, chemerin, lipocalin-2, resistin, sE-selectin, fibrinogen, complement 3, and adiponectin correlate with psoriasis and can be used as potential biomarkers for psoriasis and response to the treatment. Future studies are needed to identify additional players involved in the pathogenesis of psoriasis and to fully decipher the underlying mechanism.

Serum chemerin is associated with inflammatory and metabolic parameters-results of a population-based study

OBJECTIVE

This study aimed to confirm existing assumptions about the associations of circulating chemerin with inflammatory and metabolic parameters in a large population-based study.

METHODS

Data of 3,986 subjects from the Study of Health in Pomerania were analyzed. Residual method was used to investigate the different associations of visceral (VAT) and subcutaneous adipose tissue (SAT) with serum chemerin levels. Multivariable regression models were applied to examine the association of chemerin with high-sensitivity C-reactive protein, fibrinogen, glucose, glycated hemoglobin, lipid profile, blood pressure, diabetes, dyslipidemia, and hypertension.

RESULTS

Positive associations with chemerin were observed for VAT and SAT with a stronger relation found for VAT. After adjustment for waist circumference, increased chemerin levels were related to higher inflammatory cytokines and glycated hemoglobin and an unfavorable lipid profile. Logistic regression revealed positive associations of chemerin with dyslipidemia [highest vs. lowest quartile: odds ratio (OR) 1.56 (95% confidence interval (CI) 1.25-1.94)] and hypertension [OR 1.31 (95% CI 1.03-1.68)].

CONCLUSIONS

Chemerin levels are significantly linked to inflammation and metabolic syndrome. The majority of the detected associations persisted even after adjustment for waist circumference, suggesting that the relation of chemerin with the analyzed traits cannot be solely explained by an accumulation of adipose tissue.

Adipocyte-secreted chemerin is processed to a variety of isoforms and influences MMP3 and chemokine secretion through an NFkB-dependent mechanism

Obesity is associated with white adipose tissue (WAT) remodelling characterized by changes in cellular composition, size, and adipokine secretion. Levels of the adipokine chemerin are positively associated with obesity; however, the biological function of chemerin in WAT is poorly understood. We identified factors involved in WAT remodelling, including matrix metalloproteinase (Mmp)3 and chemokines (Ccl2, 3, 5, 7), as novel targets of chemerin signalling in mature adipocytes. Inhibition of chemerin signalling increased MMP activity and the recruitment of macrophages towards adipocyte-conditioned media. These effects were mediated through increases in NFkB signalling, suggesting that chemerin exerts an anti-inflammatory influence. We also demonstrate that multiple chemerin isoforms are present in adipocyte-conditioned media and that adipocyte-secreted chemerin, but not synthetic chemerin, recapitulates the activity of endogenous chemerin. Considered altogether, this suggests that endogenously secreted chemerin plays an autocrine/paracrine role in WAT, identifying chemerin as a therapeutic target to modulate adipose remodelling.

Hidradenitis suppurativa/Acne inversa: an endocrine skin disorder?

Hidradenitis suppurativa / acne inversa (HS) is a chronic inflammatory, debilitating skin disorder with a largely unknown etiology. However, many observations such as the typical onset of the disease after puberty, the female predominance, the pre-menstrual flare ups and the improvement during pregnancy suggest a contribution of endocrinological factors to the emergence of the disease. In addition, the reported efficacy of anti-androgen treatment on HS indicates a possible involvement of androgens in the pathogenesis. Furthermore, the common comorbidity with metabolic syndrome points to possible interactions between endocrinological and metabolic alterations in the development of HS. Taking into account the endocrine functions of the human skin, several studies investigated the effects of hormones and the behavior of the pilosebaceous unit in the skin of patients with HS. In this review we describe the current view on the hormonal dysregulation and metabolic syndrome and their role in HS.

Adipokines in psoriasis: An important link between skin inflammation and metabolic alterations

Psoriasis is a chronic inflammatory skin disease most common in Europe, North America, and Australia. The etiology and pathomechanisms underlying the evolution and persistence of the skin alterations are increasingly being understood and have led to the development of effective anti-psoriatic therapies. Apart from the skin manifestations, psoriasis is associated with the metabolic syndrome (MetS), known to increase the risk of type 2 diabetes mellitus and cardiovascular disorders. Research of the last years demonstrated a dysregulated adipokine balance as an important link between inflammation, MetS, and consequential disorders. This article describes selected adipokines and their potential role in both metabolic comorbidity and skin inflammation in psoriasis.

Association of Polymorphisms in STRA6 and RARRES2 Genes with Type 2 Diabetes in Southern Han Chinese

Stimulated by retinoic acid gene homolog 6 (STRA6) and retinoic acid receptor responder 2 (RARRES2) are candidate genes involved in the pathogenesis of type 2 diabetes mellitus (T2DM). Three tag-SNPs in STRA6 and one in RARRES2 gene were selected and genotyped with TaqMan or PCR-RFLP method in 603 populations (571 patients with T2D versus 632 control subjects) in Southern Han Chinese. We estimated the interactions between T2DM risk and genetic variants in the STRA6 and RARRES2 genes using polymerase chain reaction. Rs736118 in STRA6 gene were significantly associated with T2DM occurrence in the recessive genetic model. The genotype of rs974456 was significantly associated with T2DM in the dominant genetic model correlated to sex, MBI, and triglyceride. However, the association of other SNPs with T2DM was not found. Furthermore, smoking history and other factors may be independent risk factors for the incidence of T2DM. This study suggested that a role of STRA6 polymorphism could also be of value in predicting the risk of T2DM while RARRES2 polymorphism could not predict the risk of T2DM.

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.

Effect of an acute bout of aerobic exercise on chemerin levels in obese adults

AIMS

Serum chemerin concentrations are elevated in obese individuals and may play a role in type 2 diabetes. Exercise improves insulin sensitivity, which may be related to changes in chemerin. This study explored how an acute bout of aerobic exercise affected chemerin levels in non-diabetic obese adults.

METHODS

Blood samples from 11 obese adults were obtained during two separate conditions: sedentary (SED) and exercise (EX; 60-65% VO2peak). Samples were drawn at baseline, immediately following exercise and hourly for an additional 2h. ANOVA was used to test for differences in chemerin between conditions.

RESULTS

Unadjusted analysis showed no difference in overall change (baseline to 2h post) in chemerin between conditions. During the 2-h post-exercise period, chemerin decreased to 12% below baseline, compared to a 2.5% increase above baseline during that time period on the sedentary day (p=0.06, difference in post-to-2h change between conditions). Controlling for homeostatic model assessment of insulin resistance (HOMA-IR), a significant difference existed between EX and SED in the change in chemerin from baseline to 2-h post (p=0.02). Stratified analyses showed a consistent exercise-induced decrease in chemerin among non-insulin resistant subjects, while chemerin increased during exercise among insulin resistant subjects, and then decreased post-exercise.

CONCLUSION

An acute bout of exercise in obese individuals may elicit a drop in chemerin levels during the post-exercise period, and this response may vary based on insulin resistance.

Revisiting the adipocyte: a model for integration of cytokine signaling in the regulation of energy metabolism

Adipose tissue constitutes an extremely active endocrine organ with a network of signaling pathways enabling the organism to adapt to a wide range of different metabolic challenges, such as starvation, stress, infection, and short periods of gross energy excess. The functional pleiotropism of adipose tissue relies on its ability to synthesize and release a huge variety of hormones, cytokines, complement and growth factors, extracellular matrix proteins, and vasoactive factors, collectively termed adipokines. Obesity is associated with adipose tissue dysfunction leading to the onset of several pathologies including type 2 diabetes, dyslipidemia, nonalcoholic fatty liver, or hypertension, among others. The mechanisms underlying the development of obesity and its associated comorbidities include the hypertrophy and/or hyperplasia of adipocytes, adipose tissue inflammation, impaired extracellular matrix remodeling, and fibrosis together with an altered secretion of adipokines. Recently, the potential role of brown and beige adipose tissue in the protection against obesity has been also recognized. In contrast to white adipocytes, which store energy in the form of fat, brown and beige fat cells display energy-dissipating capacity through the promotion of triacylglycerol clearance, glucose disposal, and generation of heat for thermogenesis. Identification of the morphological and molecular changes in white, beige, and brown adipose tissue during weight gain is of utmost relevance for the identification of pharmacological targets for the treatment of obesity and its associated metabolic diseases.