The association between chemerin and homeostasis assessment of insulin resistance at baseline and after weight reduction via lifestyle modifications in young obese adults

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 role of Chemerin in human diseases

Chemerin is a protein encoded by the Rarres2 gene that acts through endocrine or paracrine regulation. Chemerin can bind to its receptor, regulate insulin sensitivity and adipocyte differentiation, and thus affect glucose and lipid metabolism. There is growing evidence that it also plays an important role in diseases such as inflammation and cancer. Chemerin has been shown to play a role in the pathogenesis of inflammatory and metabolic diseases caused by leukocyte chemoattractants in a variety of organs, but its biological function remains controversial. In conclusion, the exciting findings collected over the past few years clearly indicate that targeting Chemerin signaling as a biological target will be a major research goal in the future. This article reviews the pathophysiological roles of Chemerin in various systems and diseases,and expect to provide a rationale for its role as a clinical therapeutic target.

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.

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 levels and its genetic variants are associated with Gestational Diabetes Mellitus: a hospital-based study in a Chinese cohort

BACKGROUND

Gestational diabetes mellitus (GDM) is a glucose intolerance condition encounters for the first time in a fraction of pregnant women. The role of different host inflammatory molecules in GDM etiology has been deciphered. Chemerin is a chemoattractant protein primarily associated with the pathogenesis of type 2 diabetes, obesity, and metabolic syndrome. However, the association of chemerin and its genetic variants with the predisposition of GDM is not clear, and our present study is aimed to address the issue.

MATERIALS AND METHODS

A total of 703 Chinese women comprising of GDM (n=303), glucose tolerant pregnant women (n=211), and non-pregnant glucose tolerant controls (n=189) were recruited in the present investigation. GDM was diagnosed according to the World Health Organization recommendation for diagnosis of gestational diabetes during pregnancy. Plasma levels of chemerin were quantified by an Enzyme-linked Immunosorbent Assay (ELISA). Common variants in the chemerin gene (rs4721, rs17173617, rs7806429, and rs17173608) were genotyped by using TaqMan assay.

RESULTS

Plasma chemerin level was found higher in subjects with GDM as compared to glucose tolerant pregnant and non-pregnant women. Further, a positive correlation between plasma chemerin and HOMA-IR index suggesting an essential role of chemerin in mediating insulin resistance. Variants of rs4721 and rs17173608 polymorphisms were associated with lower levels of plasma chemerin and low HOMA-IR index. Furthermore, mutants of rs4721 and rs17173608 polymorphisms were associated with protection against the development of GDM in the Chinese cohort.

CONCLUSIONS

Plasma chemerin is elevated in GDM patients. Genetic variation in chemerin gene associated with lower plasma levels of chemerin, HOMA-IR index and protects against the development of GDM in Chinese.

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.

Low circulating chemerin levels correlate with hepatic dysfunction and increased mortality in decompensated liver cirrhosis

Nutritional status, infections, inflammation and extrahepatic organ dysfunction are critical factors for the progression of chronic liver disease. Chemerin is an immune-metabolically and chemotactically active adipokine and we hypothesized that it is associated with disease severity and prognosis in patients with advanced decompensated cirrhosis. Therefore, we measured serum concentrations of chemerin in a prospectively characterized cohort of 80 patients with decompensated cirrhosis and ascites and assessed the associations with markers of disease severity and short-term outcome at 28 days. In a subset of patients (n = 40), ascitic fluid chemerin was determined. Advanced liver disease was associated with decreased serum but not ascitic chemerin levels. Serum chemerin correlated with markers of hepatic function (total bilirubin, albumin, INR) and inversely correlated with indicators of portal hypertension (platelet count, gastrointestinal bleeding) but not with extrahepatic organ failure and systemic inflammation. Patients presenting with acute-on-chronic liver failure or infection did not exhibit altered serum or ascitic fluid chemerin concentrations. However, serum chemerin levels below 87 ng/ml predicted an increased risk for mortality or liver transplantation within 28 days independently of MELD and infections. We conclude that low serum chemerin is an independent adverse prognostic factor in patients with advanced decompensated cirrhosis.

Six weeks of combined aerobic and resistance exercise using outdoor exercise machines improves fitness, insulin resistance, and chemerin in the Korean elderly: A pilot randomized controlled trial

BACKGROUND

The aim of this study was to investigate the effect of a six-week-long exercise program using outdoor exercise equipment on fitness, insulin resistance and adipocytokines among Korean elderly.

METHODS

A total of 47 participants were randomized into one of the following three groups; control, resistance exercise or combined exercise (aerobic and resistance exercise). The resistance exercise group completed three resistance types of exercise. The combined exercise group completed five exercises, including three resistance types of exercise and two aerobic types of exercise. Participants' body composition, fitness level, homeostasis model assessment of insulin resistance (HOMA-IR), and adipocytokines were measured at baseline and at the end of six weeks.

RESULTS

After six weeks of exercise training, participants in the combined exercise group exhibited significant reduction in insulin, HOMA-IR and chemerin levels, while significant reduction was observed in HOMA-IR only in the resistance exercise group compared with the control group. Meanwhile, six weeks of exercise training, whether resistance exercise alone or combined, significantly improved upper body muscular strength/endurance and physical function compared to the control group.

CONCLUSIONS

Six weeks of combined exercise using outdoor exercise equipment was effective in improving fitness, HOMA-IR, circulating chemerin levels, and other known risk factors of chronic diseases.

Positive association between the changes in chemerin and adiponectin levels after weight reduction

PURPOSE

Adiponectin and chemerin have been reported their associations with insulin resistance and chronic inflammation. However, the relationship between adiponectin and chemerin themselves has not been fully elucidated. Therefore, we investigated the effects of changes in adiponectin and chemerin levels after a weight intervention.

MATERIALS AND METHODS

We recruited 136 healthy overweight or obese subjects from 2006 to 2009 and provided all participants lifestyle modification therapy with diet consultations over 16 weeks. We assigned the participants to take orlistat or sibutramine or to a no prescription group. We analyzed the data using paired t-tests, Pearson's partial correlation analysis, and stepwise multiple linear regression analysis.

RESULTS

∆ in chemerin was positively correlated with ∆ in adiponectin (r = 0.29, p < 0.01), and these trends were similar in the insulin-resistant (r = 0.35, p = 0.03) and insulin-sensitive (r = 0.27, p < 0.01) groups. In multiple regression analyses, Δadiponectin, ΔQUICKI (quantitative insulin-sensitivity check index), Δglucose, and ΔDBP were significantly associated with Δchemerin in the insulin-resistant group, and initial chemerin level, ΔQUICKI, ΔBMI (body mass index), and taking orlistat were associated with Δchemerin in the insulin-sensitive group.

CONCLUSIONS

Changes in chemerin levels were positively associated with changes in adiponectin levels. The association between these changes might be related to chemerin's dual inflammatory and anti-inflammatory effects or insulin resistance and insulin sensitivity enhancing effects, depending on the metabolic conditions. Additional studies are needed to clarify the mechanisms that underlie the effects of adiponectin and chemerin.

Novel Molecules Regulating Energy Homeostasis: Physiology and Regulation by Macronutrient Intake and Weight Loss

Excess energy intake, without a compensatory increase of energy expenditure, leads to obesity. Several molecules are involved in energy homeostasis regulation and new ones are being discovered constantly. Appetite regulating hormones such as ghrelin, peptide tyrosine-tyrosine and amylin or incretins such as the gastric inhibitory polypeptide have been studied extensively while other molecules such as fibroblast growth factor 21, chemerin, irisin, secreted frizzle-related protein-4, total bile acids, and heme oxygenase-1 have been linked to energy homeostasis regulation more recently and the specific role of each one of them has not been fully elucidated. This mini review focuses on the above mentioned molecules and discusses them in relation to their regulation by the macronutrient composition of the diet as well as diet-induced weight loss.

The adipokine chemerin amplifies electrical field-stimulated contraction in the isolated rat superior mesenteric artery

The adipokine chemerin causes arterial contraction and is implicated in blood pressure regulation, especially in obese subjects with elevated levels of circulating chemerin. Because chemerin is expressed in the perivascular adipose tissue (PVAT) that surrounds the sympathetic innervation of the blood vessel, we tested the hypothesis that chemerin (endogenous and exogenous) amplifies the sympathetic nervous system in mediating electrical field-stimulated (EFS) contraction. The superior mesenteric artery, with or without PVAT and with endothelium and sympathetic nerve intact, was mounted into isolated tissue baths and used for isometric contraction and stimulation. Immunohistochemistry validated a robust expression of chemerin in the PVAT surrounding the superior mesenteric artery. EFS (0.3-20 Hz) caused a frequency-dependent contraction in isolated arteries that was reduced by the chemerin receptor ChemR23 antagonist CCX832 alone (100 nM; with, but not without, PVAT), but not by the inactive congener CCX826 (100 nM). Exogenous chemerin-9 (1 μM)-amplified EFS-induced contraction in arteries (with and without PVAT) was blocked by CCX832 and the α-adrenergic receptor antagonist prazosin. CCX832 did not directly inhibit, nor did chemerin directly amplify, norepinephrine-induced contraction. Whole mount immunohistochemical experiments support colocalization of ChemR23 with the sympathetic nerve marker tyrosine hydroxylase in superior mesenteric PVAT and, to a lesser extent, in arteries and veins. These studies support the idea that exogenous chemerin modifies sympathetic nerve-mediated contraction through ChemR23 and that ChemR23 may be endogenously activated. This is significant because of the well-appreciated role of the sympathetic nervous system in blood pressure control.

Chemerin: a new biomarker to predict postendoscopic retrograde cholangiopancreatography pancreatitis

INTRODUCTION

Individuals with increased visceral adiposity are considered to be more sensitive and more prone to severe acute pancreatitis because of the inflammatory microenvironment they have. We hypothesized that insulin resistance, adipokines, and proinflammatory cytokines that markedly affect the course of pancreatitis can contribute toward development of postendoscopic retrograde cholangiopancreatography (post-ERCP) pancreatitis (PEP) and aimed to investigate the association between PEP risk and preprocedural serum vaspin, chemerin, tumor necrosis factor α, interleukin-6 (IL-6) levels, and homeostasis model assessment of insulin resistance.

PATIENTS AND METHODS

Eighty-two patients with a diagnosis of choledocholithiasis and 30 controls were enrolled. Preprocedural chemerin, vaspin, IL-6, and well-known PEP risk factors were compared between PEP and non-PEP groups.

RESULTS

The mean age of the patients was 56.3±14.4 years; 52 patients were women. Adipocytokine levels, BMIs, and waist circumferences of the patient group were found to be higher than those of the controls. Total cannulation success and the mean procedure time were 82.9% and 28.7±8.8 min, respectively. PEP developed in 12 (14.6%) patients. Chemerin levels in the PEP group were higher than those in the non-PEP group (580.2±172.5 vs. 392.2±168.2 ng/ml, P<0.01). Insulin resistance was higher in the PEP group than the non-PEP group (P=0.001), but there was no significant difference between PEP and non-PEP groups in terms of preprocedural vaspin, tumor necrosis factor α, IL-6, and C-reactive protein levels. According to logistic regression analysis, increased chemerin levels, homeostasis model assessment of insulin resistance 2.5 or greater, and pancreatic duct cannulation were found to be independent risk factors for PEP [odds ratio (OR)=1.006, P=0.006; OR=4.57, P=0.05; OR=6.54, P=0.02].

CONCLUSION

Elevated serum chemerin levels and insulin resistance are independent risk factors of PEP development.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cardiopulmonary fitness, adiponectin, chemerin associated fasting insulin level in colorectal cancer patients

PURPOSE

Since circulating level of insulin is associated with colorectal cancer prognosis, it is important to identify factors contributing to fasting insulin level in colorectal cancer patients. The purpose of the current study is to investigate the association of physical fitness, adiponectin, and chemerin levels with circulating level of insulin in colorectal cancer patients.

METHODS

A total of 123 stage II-III colorectal cancer patients who completed standard cancer treatment were recruited. Anthropometric characteristics, fitness measurements, fasting insulin level, homeostasis model assessment of insulin resistance, lipid profiles, and adiponectin and chemerin levels were analyzed.

RESULT

Cardiopulmonary fitness level inversely associated with fasting insulin levels (the least fit (1st tertile): 8.11 ± 0.64, moderately fit (2nd tertile): 6.02 ± 0.63, and highly fit (3rd tertile): 5.58 ± 0.66 μU/ml, unfit vs. moderately fit, p < 0.01; unfit vs. highly fit, p < 0.05) after adjustment for gender, age, stage, and BMI. In addition, fasting adiponectin and chemerin levels were associated with fasting insulin levels after adjustment for gender, age, stage, and BMI. In our combined analyses, participants with high adiponectin and low chemerin levels showed significantly lower fasting insulin levels (4.92 ± 0.75 vs. 8.07 ± 0.80 μU/ml, p < 0.01) compared with participants with low adiponectin and high chemerin levels. Multiple linear regression analysis confirmed that cardiopulmonary fitness and adiponectin levels (β = -0.299, p = 0.002; β = -0.201, p = 0.033) were independently associated with fasting insulin level.

CONCLUSION

Our results suggest that physical fitness and adiponectin and chemerin levels may contribute to circulating levels of insulin. These results suggest that exercise may influence the prognosis of colorectal cancer patients by influencing physical fitness level, circulating levels of adiponectin and chemerin.

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.

Are serum chemerin levels different between obese and non-obese polycystic ovary syndrome women?

The objective of this study is to measure serum chemerin levels in women with polycystic ovary syndrome (PCOS) and assess their relationship with clinical, metabolic, and hormonal parameters. One hundred eighteen PCOS women and 114 healthy women were recruited in this study. Their blood pressure, body mass index (BMI), waist circumference and waist-to-hip ratio (WHR), fasting insulin (FIN), fasting plasma glucose (FPG), blood serum sex hormone, and blood lipid were measured. Serum chemerin, leptin, and adiponectin were measured by ELISA. Serum chemerin was significantly higher in the obese PCOS group (47.62 ± 11.27 ng/mL) compared with non-obese PCOS (37.10 ± 9.55 ng/mL) and the obese (33.71 ± 6.17 ng/mL) and non-obese (25.78 ± 6.93 ng/mL) control groups (p < 0.05). Serum chemerin was positively related to BMI, waist circumference, WHR, testosterone (T), FPG, FIN, homeostasis model assessment of insulin resistance (HOMA-IR), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL-C), LDL-C/high-density lipoprotein(HDL-C), TC/HDL-C and serum leptin, while negatively related to glucose-to-insulin ratio (G/I), HDL-C, and adiponectin levels. Multiple linear regression analysis revealed HOMA-IR, leptin, and TC were the significant influencing factors of chemerin levels (p < 0.05). Increased serum chemerin in PCOS woman with or without obesity suggested that chemerin may be involved in the development of the pathogenesis of PCOS.

Diet-induced increases in chemerin are attenuated by exercise and mediate the effect of diet on insulin and HOMA-IR

OBJECTIVES

Chemerin concentrations are elevated in obesity and associated with inflammation and insulin resistance. Exercise improves insulin sensitivity, which may be facilitated by changes in chemerin. We explored the effects of chronic exercise on chemerin levels in diet-induced obese mice.

METHODS

We divided 40 mice into 4 groups: high-fat diet/exercise, high-fat diet/sedentary, normal diet/exercise, and normal diet/sedentary. A 9-week dietary intervention was followed by a 12-week exercise intervention (treadmill run: 11 m/min for 30 min, 3×/week). We analyzed blood samples before and after the exercise intervention. We used t-tests and linear regression to examine changes in chemerin, insulin resistance, and inflammatory markers, and associations between changes in chemerin and all other biomarkers.

RESULTS

Chemerin increased significantly across all mice over the 12-week intervention (mean ± SD = 40.7 ± 77.8%, p = 0.01), and this increase was smaller in the exercise versus sedentary mice (27.2 ± 83.9% versus 54.9 ± 70.5%, p = 0.29). The increase among the high-fat diet/exercise mice was ~44% lower than the increase among the high-fat diet/sedentary mice (55.7 ± 54.9% versus 99.8 ± 57.7%, p = 0.12). The high-fat diet mice showed significant increases in insulin (773.5 ± 1286.6%, p < 0.0001) and homeostatic model assessment of insulin resistance (HOMA-IR; 846.5 ± 1723.3%, p < 0.01). Mediation analyses showed that increases in chemerin explained a substantial amount of the diet-induced increases in insulin and HOMA-IR.

CONCLUSION

Chronic exercise may attenuate diet-driven increases in circulating chemerin, and the insulin resistance associated with a high-fat diet may be mediated by diet-induced increases in chemerin.

Relationship of plasma level of chemerin and vaspin to early atherosclerotic changes and cardiac autonomic neuropathy in adolescent type 1 diabetic patients

OBJECTIVE

Our objective was to evaluate the relationship of plasma level of chemerin and vaspin to early atherosclerotic changes and cardiac autonomic neuropathy (CAN) in adolescent type 1 diabetic patients.

PATIENTS AND METHODS

The study included 62 type 1 diabetic patients and 30 healthy volunteers of the same age and sex. Blood samples were taken for assessment of chemerin, vaspin, asymmetric dimenthylarginine (ADMA), and oxidized low-density lipoprotein (OxLDL) by enzyme-linked immunosorbent assay (ELISA) technique. Also, blood samples were taken for analysis of glycosylated hemoglobin; lipid profiles and urine samples were taken for assessment of albumin/creatinine ratio. Twenty-four-hour holter [for assessment of time domain heart rate variability (HRV)] and carotid intima-media thickness (CIMT) were also done. The t-test or Mann-Whitney U-test for independent variables, Pearson's or Spearman's correlation, and stepwise multiple regression analysis were used.

RESULTS

The mean age of diabetic patients was 16.3±1.5 years, and mean duration of diabetes was 9.4±2.9 years. Chemerin, vaspin, OxLDL, and albumin/creatinine ratio were significantly higher, whereas ADMA was significantly lower than the controls. By stepwise multiple regression analysis, vaspin had a relation with a standard deviation difference RR (SDARR) and waist/height ratio. Conversely, chemerin had a relation with OxLDL. Albumin/creatinine ratio had a significant positive correlation with chemerin and OxLDL, and a negative correlation with ADMA.

CONCLUSIONS

Type 1 diabetic patients had impaired time domain HRV associated with increased CIMT. Vaspin had a significant relation to CAN, whereas chemerin, ADMA, and OxLDL had a significant correlation with albumin/creatinine ratio that reflects their role in renal affection.

Chemerin as a marker of body fat and insulin resistance in women with polycystic ovary syndrome

Adipocytokines may alter normal metabolic function and play an important role in the pathophysiology of polycystic ovary syndrome (PCOS). We prospectively evaluated a cohort of obese and non-obese women with PCOS and non-PCOS controls for both novel (chemerin and omentin-1) and established (leptin and adiponectin) adipokines. Compared with age-matched controls, non-obese women with PCOS had decreased serum omentin-1 (191.1 ng/ml versus 269.7 ng/ml, p = 0.0001), while serum chemerin was not significantly altered in women with PCOS (53.95 ng/ml versus 48.61 ng/ml, p = 0.11). The findings were similar in the entire group of women with PCOS. However, in women with PCOS, chemerin correlated with leptin (r = 0.508, p = 0.004), adiponectin (r = -0.36, p = 0.014), and the leptin/adiponectin (L/A) ratio (r = 0.605, p < 0.0001), while there were no such correlations with omentin-1. In women with PCOS, chemerin correlated with BMI (r = 0.317, p = 0.034), abdominal subcutaneous fat (r = 0.451, p = 0.0019), and insulin resistance (HOMA-IR, r = 0.428, p = 0.0034), while omentin-1 did not correlate with any parameter. These data suggest that chemerin although not significantly elevated in women with PCOS correlates with adiposity and insulin resistance, and it is the single best adipokine measured in this regard. Chemerin, through its inflammatory role as a chemo-attractant in adipose tissue, may be an important determinant of insulin resistance in PCOS.

Exercise-induced lowering of chemerin is associated with reduced cardiometabolic risk and glucose-stimulated insulin secretion in older adults

OBJECTIVE

To determine the effect of exercise on chemerin in relation to changes in fat loss, insulin action, and dyslipidemia in older adults.

PARTICIPANTS

Thirty older (65.9±0.9yr) obese adults (BMI:34.5±0.7kg/m2).

SETTING

Single-center, Cleveland Clinic.

DESIGN

Prospective clinical trial.

INTERVENTION

Twelve-weeks of exercise training (60minutes/day, 5day/week at ~85% HRmax). Subjects were instructed to maintain habitual nutrient intake.

MEASUREMENTS

Plasma chemerin was analyzed using an enzyme-linked immunosorbent assay. Peripheral and hepatic insulin sensitivity was assessed using a euglycemic-hyperinsulinic clamp with glucose kinetics. First-phase and total glucose-stimulated insulin secretion (GSIS) was calculated from an oral glucose tolerance test. Fasting blood lipids (cholesterol, triglycerides), total/visceral fat (dual-x-ray absorptiometry and computerized tomography) and cardiorespiratory fitness (treadmill test) were also tested pre and post intervention.

RESULTS

Exercise increased fitness and reduced total/visceral fat, blood lipids, and first-phase GSIS (P<0.05). Training also increased peripheral insulin sensitivity and lowered basal/insulin-related hepatic glucose production (P<0.01). The intervention reduced chemerin (87.1±6.0 vs. 78.1±5.8ng/ml; P=0.02), and the reduction correlated with decreased visceral fat (r=0.50, P=0.009), total body fat (r=0.42, P=0.02), cholesterol (r=0.38, P=0.04), triglycerides (r=0.36, P=0.05), and first-phase and total GSIS (r=0.39, P=0.03 and r=0.43, P=0.02, respectively).

CONCLUSIONS

Lower chemerin appears to be an important hormone involved in cardiometabolic risk and GSIS reduction following exercise in older adults.