Serum Chemerin in Obese Children and Adolescents Before and After L-Carnitine Therapy: Relation to Nonalcoholic Fatty Liver Disease and Other Features of Metabolic Syndrome

Serum Chemerin Levels Correlate With Severity of Dysglycemia in Young Adult Women With Polycystic Ovary Syndrome

Context

A subset of polycystic ovary syndrome (PCOS) individuals also have type 2 diabetes (T2D); an unmet need to identify this subgroup exists.

Objective

We looked at the potential role of serum chemerin, a proinflammatory adipokine, in identifying dysglycemic PCOS.

Methods

A total of 93 PCOS and 33 healthy controls were classified, based on fasting and 2-hour plasma glucose levels (2hPGPG) and glycated hemoglobin A1c (HbA1c) (%) into normoglycemic (n = 34), dysglycemic (n = 33), and T2D (n = 26). Serum chemerin were measured by enzyme-linked immunosorbent assay. Homeostatic model 2 assessment of insulin resistance (HOMA-2IR) and homeostatic model 2 assessment of β-cell function (HOMA-2β) were computed using serum C-peptide.

Results

Metabolic syndrome was present in 9.7% (National Cholesterol Education Program) of PCOS. Waist circumference, body fat (%), 2hPGPG, and HbA1c levels were significantly higher in T2D group. Serum triglycerides/high-density lipoprotein cholesterol (TGs/HDL-c) ratio was increased in PCOS individuals with T2D; no significant changes in total cholesterol and LDL-c levels were seen. Serum chemerin levels were significantly higher (P < .001) in the PCOS group. Total body fat (%), 2hPGPG, HbA1c, and TG/HDL-c ratio correlated positively with chemerin levels. Serum chemerin levels correlated positively with HOMA2IR and negatively with HOMA-2β. On receiver operating characteristic curve analysis, a serum chemerin cutoff level of greater than 309.3 ng/mL differentiated PCOS individuals with dysglycemia from those without (sensitivity 85.71%, specificity 89.47%). The Cohen kappa test revealed a substantial agreement (P < .001) between chemerin cutoff and 2hPGPG levels greater than 200 mg/dL. The present study is arguably the first ever to define a serum chemerin cutoff to distinguish PCOS individuals with T2D from those without.

Conclusion

Elevated serum chemerin levels reliably identify PCOS individuals with dysglycemia. Further, longitudinal studies with larger samples are required to confirm this association.

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

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

Aerobic exercise-induced decrease of chemerin improved glucose and lipid metabolism and fatty liver of diabetes mice through key metabolism enzymes and proteins

Our previous studies have implicated an important role of adipokine chemerin in exercise-induced improvements of glycolipid metabolism and fatty liver in diabetes rat, but the underlying mechanisms remain unknown. This study first used an exogenous chemerin supplement to clarify the roles of decreased chemerin in exercised diabetes mice and possible mechanisms of glucose and lipid metabolism key enzymes and proteins [such as adipose triglyceride lipase (ATGL), lipoprotein lipase (LPL), phosphoenolpyruvate carboxykinase (PEPCK), and glucose transporter 4 (GLUT4)]. In addition, two kinds of adipose-specific chemerin knockout mice were generated to demonstrate the regulation of chemerin on glucose and lipid metabolism enzymes and proteins. We found that in diabetes mice, exercise-induced improvements of glucose and lipid metabolism and fatty liver, and exercise-induced increases of ATGL, LPL, and GLUT4 in liver, gastrocnemius and fat were reversed by exogenous chemerin. Furthermore, in chemerin knockdown mice, chemerin(-/-)∙adiponectin mice had lower body fat mass, improved blood glucose and lipid, and no fatty liver; while chemerin(-/-)∙fabp4 mice had hyperlipemia and unchanged body fat mass. Peroxisome proliferator-activated receptor γ (PPARγ), ATGL, LPL, GLUT4 and PEPCK in the liver and gastrocnemius had improve changes in chemerin(-/-)·adiponectin mice while deteriorated alterations in chemerin(-/-)·fabp4 mice, although PPARγ, ATGL, LPL, and GLUT4 increased in the fat of two kinds of chemerin(-/-) mice. CONCLUSIONS: Decreased chemerin exerts an important role in exercise-induced improvements of glucose and lipid metabolism and fatty liver in diabetes mice, which was likely to be through PPARγ mediating elevations of ATGL, LPL and GLUT4 in peripheral metabolic organs.

Metabolomic Analysis of Pediatric Patients with Idiosyncratic Drug-Induced Liver Injury According to the Updated RUCAM

Hepatotoxicity, a common adverse drug effect, has been extensively studied in adult patients. However, it is equally important to investigate this condition in pediatric patients to develop personalized treatment strategies for children. This study aimed to identify plasma biomarkers that characterize hepatotoxicity in pediatric patients through an observational case-control study. Metabolomic analysis was conducted on 55 pediatric patients with xenobiotic liver toxicity and 88 healthy controls. The results revealed clear differences between the two groups. Several metabolites, including hydroxydecanoylcarnitine, octanoylcarnitine, lysophosphatidylcholine, glycocholic acid, and taurocholic acid, were identified as potential biomarkers (area under the curve: 0.817; 95% confidence interval: 0.696-0.913). Pathway analysis indicated involvement of primary bile acid biosynthesis and the metabolism of taurine and hypotaurine (p < 0.05). The findings from untargeted metabolomic analysis demonstrated an increase in bile acids in children with hepatotoxicity. The accumulation of cytotoxic bile acids should be further investigated to elucidate the role of these metabolites in drug-induced liver injury.

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

Background

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

Aim of the study

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

Material and methods

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

Results

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

Conclusions

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

Maternal L-carnitine supplementation promotes brown adipose tissue thermogenesis of newborn goats after cold exposure

Brown adipose tissue (BAT) is an important component of energy expenditure and necessary to maintain body temperature for newborn mammals. In the previous study, we found that L-carnitine was enriched in BAT and promoted BAT adipogenesis and thermogenesis in goat brown adipocytes. However, whether dietary L-carnitine regulates BAT heat production and energy expenditure in lambs remains unclear. In this study, maternal L-carnitine supplementation elevated the rectal temperature, as well as the expression of UCP1 and mitochondrial DNA content to promote BAT thermogenesis in newborn goats. Moreover, maternal L-carnitine supplementation increased the levels of triglycerides (TG), non-esterified fatty acids (NEFA), and lactate in plasma, as well as the content of lipid droplet and glycogen in BAT of newborn goats. Lipidomic analysis showed that maternal L-carnitine supplementation remodeled the lipid composition of BAT in newborn goats. L-carnitine significantly increased the levels of TG and diglyceride (DG) and decreased the levels of glycerophospholipids and sphingolipids in BAT. Further studies showed that L-carnitine promoted TG and glycogen deposition in brown adipocytes through AMPKα. Our results indicate that maternal L-carnitine supplementation promotes BAT development and thermogenesis in newborn goats and provides new evidence for newborn goats to maintain body temperature in response to cold exposure.

Serum Chemerin and Apelin Levels in Obese Children: Relation to Endothelial Function and Inflammation from a Cross-sectional Case–Control Study

BACKGROUND: Childhood obesity is a global threat with subsequent health problems among which and most important is cardiovascular problems. It is now claimed that adipokines secreted by adipose tissue are responsible for such consequences. Newly discovered adipokines chemerin and apelin are under investigation for their link with obesity related co-morbidites. AIM: The aim of the present study was to assess the serum levels of chemerin and apelin in obese children and to explore the correlation between these two biomarkers and the inflammatory as well as the endothelial cell activation markers PATIENTS AND METHODS: This study was a cross-sectional case control study that comprised 45 pre-pubertal obese children aged (6– < 12) years old of both sexes (22 males and 23 females), in addition to 45 matched age and sex lean children serving as controls (21 males and 24 females). Serum levels of chemerin, apelin, ICAM-1, E-selectin and hs-CRP were measured for obese and controls. RESULTS: Obese children showed higher levels of chemerin, apelin, ICAM-1 and E-selectin than controls. Chemerin and apelin showed significant correlations with all parameters except for age. Anthropometric parameters with hs-CRP revealed significant correlation even after adjustment for age and sex while apelin only showed a significant correlation with age. Multiple regression analyses with hs -CR , E-selectin and ICAM-1 as dependent variables and BMI Z score ,age, sex, chemerin and apelin as independent variables showed the effect of chemerin and apelin on  the increased  levels of hs -CR , E-selectin and ICAM-1 . CONCLUSION: Elevated levels of chemerin and apelin may serve as indices of ongoing obesity-related disorders in obese children.

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

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

Chlorogenic acid inhibits trimethylamine-N-oxide formation and remodels intestinal microbiota to alleviate liver dysfunction in high L-carnitine feeding mice

High L-carnitine ingestion has been shown to cause liver injury, mechanically due to an elevated circulating level of trimethylamine-N-oxide (TMAO), a gut microbiota-derived metabolite from L-carnitine. This study aimed to investigate whether chlorogenic acid (CGA), a health-promoting polyphenol, could inhibit TMAO formation and thereafter might prevent L-carnitine-induced liver injury in mice. Feeding of mice with 3% L-carnitine in drinking water increased the serum and urinary levels of TMAO (p < 0.01 vs. Normal), whereas the serum and urinary TMAO formation was sharply reduced by CGA administration (p < 0.01). At the phylum level, CGA inhibited the L-carnitine-induced increase in the abundance of Firmicutes and Proteobacteria, while it promoted Bacteroidetes. At the genus level, CGA notably increased the abundance of Akkermansia and Bacteroides, but reduced the population of Erysipelatoclostridium, Faecalibaculum and Erysipelotrichaceae in high L-carnitine feeding mice. Meanwhile, CGA caused strong inhibition against the increase of liver injury markers (i.e. AST, ALT and ALP), hepatic inflammatory cytokines (i.e. IL-1, IL-6, TNF-α and TNF-β) and dyslipidemia (i.e. TC, TG, LDL-C and HDL-C) in L-carnitine-fed mice (p < 0.05). These findings suggest that CGA holds great potential to alleviate liver dysfunction induced by high L-carnitine ingestion. The beneficial effect might be attributed to the protection against TMAO formation and the improvement of the health-promoting gut microbiota, as well as the antioxidant and anti-inflammatory properties of CGA.

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.

Role of Carnitine in Non-alcoholic Fatty Liver Disease and Other Related Diseases: An Update

Carnitine is an amino acid-derived substance that coordinates a wide range of biological processes. Such functions include transport of long-chain fatty acids from the cytoplasm to the mitochondrial matrix, regulation of acetyl-CoA/CoA, control of inter-organellar acyl traffic, and protection against oxidative stress. Recent studies have found that carnitine plays an important role in several diseases, including non-alcoholic fatty liver disease (NAFLD). However, its effect is still controversial, and its mechanism is not clear. Herein, this review provides current knowledge on the biological functions of carnitine, the “multiple hit” impact of carnitine on the NAFLD progression, and the downstream mechanisms. Based on the “multiple hit” hypothesis, carnitine inhibits β-oxidation, improves mitochondrial dysfunction, and reduces insulin resistance to ameliorate NAFLD. L-carnitine may have therapeutic role in liver diseases including non-alcoholic steatohepatitis, cirrhosis, hepatocellular carcinoma, alcoholic fatty liver disease, and viral hepatitis. We also discuss the prospects of L-carnitine supplementation as a therapeutic strategy in NAFLD and related diseases, and the factors limiting its widespread use.

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

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

Effect of l-carnitine supplementation on children and adolescents with nonalcoholic fatty liver disease (NAFLD): a randomized, triple-blind, placebo-controlled clinical trial

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in the pediatric population at global level. Present study aims to assess the effect of l-carnitine supplementation on the NAFLD in children and adolescents.

METHODS

This randomized, triple-blind, placebo-controlled clinical trial was conducted in 2018-2019. Study was carried out in NAFLD participants (5-15 years). They were randomly assigned to receive either 50 mg/kg/day l-carnitine twice a day or identical placebo per day for three months. Liver enzymes and liver ultrasonography were assessed before and after the intervention. Both groups received similar consultation for lifestyle changes.

RESULTS

Overall, 55 participants completed the study, 30 patients in the l-carnitine group and 25 patients in placebo group. Mean changes of anthropometric measurements did not have significant differences between groups (p>0.05). No significant differences in the mean changes of aspartate aminotransferase (AST) (p=0.82) and alanine aminotransferase (ALT) (p=0.76) levels were documented between two groups. Based on within-group analysis, there were significant changes in AST and ALT levels before and after the intervention in both groups. The sonographic grades of fatty liver were not significantly different between two groups before (p=0.94) and after intervention (p=0.93).

CONCLUSIONS

In the present clinical trial, L-carnitine did not have significant effect on improving biochemical and sonographic markers of NAFLD in children and adolescents. Future studies are necessary to evaluate the applicability and efficacy of long-term l-carnitine supplementation to treatment of NAFLD in pediatric population.

TRIAL REGISTRATION

IRCT20170628034786N2.

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.

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

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

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

Background

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

Methods

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

Results

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

Conclusions

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

DISCUSSION

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

Aerobic exercise decreases chemerin/CMKLR1 in the serum and peripheral metabolic organs of obesity and diabetes rats by increasing PPARγ

Objective

To investigate the influences of exercise on the levels of chemerin and its receptor chemokine-like receptor (CMKLR1) in the peripheral metabolic organs of obesity and diabetes rats, and whether the mechanism is related to peroxisome proliferator activated receptor γ (PPARγ), a key modulator of glycolipid metabolism.

Methods

Obesity rats induced by 8-week high fat diet (HFD) were randomly divided into obesity group (OB) and exercised obesity group (EOB) with 8 rats each group, and 40 diabetes rats established by 8-week HFD plus low dose of streptozotocin were randomly divided into 4 groups: diabetes group (DM), exercised diabetes group (EDM), exercised diabetes plus PPARγ agonist pioglitazone group (EDP), and exercised diabetes plus PPARγ antagonist GW9662 group (EDG). The rats in EOB, EDM, EDG and EDP groups participated in a 4-week moderate-intensity aerobic exercise on a treadmill with gradually increasing intensity, once a day and 6 days/week, and 30 min before each exercise EDP and EDG were administrated to the rats in EDP and EDG groups, respectively. Before and after 4-week exercise, glycolipid metabolism indexes, serum chemerin and the levels of chemerin and CMKLR1 in metabolic organs such as liver and gastrocnemius were investigated (not detecting adipose for no available perirenal adipose from DM rats).

Results

(1) In addition to serum chemerin, the levels of chemerin and CMKLR1 in the liver and gastrocnemius of EOB and EDM rats were declined, accompanied with the improved glycolipid metabolism. (2) The decreased chemerin/CMKLR1 in the EDM rats were reversed by PPARγ antagonist GW9662 and further strengthened by PPARγ agonist pioglitazones.

Conclusions

Besides serum chemerin, the levels of chemerin/CMKLR1 in the metabolic organs of obesity and diabetes rats were alleviated by exercise, which were likely to be associated with the improvement of glycolipid metabolism. Exercise-induced decrements of chemerin/CMKLR1 in the diabetes rats were mediated by PPARγ.

Electronic supplementary material

The online version of this article (10.1186/s12986-019-0344-9) contains supplementary material, which is available to authorized users.

The effect of l-carnitine supplementation on lipid profile and glycaemic control in adults with cardiovascular risk factors: A systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND & AIMS

Several randomized clinical trials (RCTs) have investigated the effect of l-carnitine supplementation on lipid profile and glycaemic control in adults with cardiovascular risk factors; however, the results were conflicting. Therefore, a meta-analysis was performed to assess the effect of l-carnitine on lipid profile and glycaemic control in adults with cardiovascular risk factors.

METHODS

We searched PubMed, Scopus, Cochrane Databases, Google Scholar, ProQuest, Web of Science and Embase for randomized, placebo-controlled human trials that investigated the effect of l-carnitine supplementation on lipid profile and glycaemic control up to April 2017. From the eligible trials, 24 articles were selected for the meta-analysis. The meta-analysis was performed in a random-effects model. Heterogeneity was determined by I² statistics and Cochrane Q test.

RESULTS

The result showed significant effect of l-carnitine on TC (WMD: -13.73 [95% CI: -22.28, -5.17] mg/dL; P < 0.001), LDL-C (WMD = - 7.70 [95% CI: - 11.80, -3.61]mg/dL; p < 0.001), HDL-C (WMD = 0.82 [95% CI: 0.44, 1.21] mg/dL; P > 0.001), Lp(a) (WMD = - 7.13 [95% CI: -9.82,- 4.43]mg/dL; P < 0.001), FPG (WMD = -6.25 [95% CI: -10.35, -2.16] mg/dL; P < 0.001), HbA1C (WMD (%) = - 0.35 [95% CI: -0.65,- 0.05]; p = 0.02) and HOMA-IR (WMD (%) = - 0.94 [95% CI: -1.89, -0.00]; P = 0.05). No effect of l-carnitine was detected in TG, Apo A-I and Apo B 100 on pooled effect size. Additionally, sensitivity analysis showed l-carnitine supplementation could improve glycaemic control, particularly along with hypocaloric diet.

CONCLUSION

This meta-analysis showed that l-carnitine supplementation could improve lipid profile levels, particularly in doses more than 1500 mg/day. More RCTs with large sample sizes, focusing on gut microbiome profiles and dietary patterns are needed to better understand the effect of l-carnitine on patients with cardiovascular risk factors.

Decrease in serum chemerin through aerobic exercise plus dieting and its association with mitigation of cardio-metabolic risk in obese female adolescents

BACKGROUND

The objective of this study was to determine the effects of a 4-week aerobic exercise plus dieting intervention on serum chemerin in obese female adolescents and its possible role in mitigating cardio-metabolic risk including glucose and lipid metabolism, central fat and inflammation.

METHODS

Fifty obese female adolescents were randomly divided into two groups: exercise plus dieting group (n=30) and dieting group (n=20). The participants in the exercise plus dieting group completed 4 weeks of moderate aerobic exercise combined with dieting, while the subjects in the dieting group undertook only dieting. Before and after the experiments, anthropometric index, parameters of glucose and lipid metabolism, serum chemerin and classic inflammatory indicators (C-reactive protein [CRP], tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β], IL-6, leptin and adiponectin) were measured.

RESULTS

Compared with the dieting group, a decrease in serum chemerin was found in the exercise plus dieting group, accompanied by significant improvements in anthropometric index, glucose and lipid metabolism and inflammatory factors. In addition, a higher serum chemerin level was found in obese adolescents with metabolic syndrome (MetS), and the disappearance of MetS induced by exercise plus dieting might be related to the decrease in chemerin. Correlation analysis showed the correlations of the decrease in chemerin with the changes in body fat, glucose and lipid metabolic index, leptin and adiponectin/leptin ratio.

CONCLUSIONS

This is the first report that as short a duration as 4-week aerobic exercise plus dieting decreased serum chemerin in obese female adolescents, which might be associated with the improvement in glucose and lipid metabolism, mitigation of inflammation and decrease in MetS incidence, thus lowering cardio-metabolic risk, while no health benefit resulted from slight dieting.