Resistin levels are related to fat mass, but not to body mass index in children

Adipokines expression profiles in both plasma and peri renal adipose tissue in Large White and Meishan sows: A possible involvement in the fattening and the onset of puberty

In pig, backfat deposition is strongly related to the growth and reproductive performance. However, the molecular regulatory mechanisms of adipose tissue are not clearly understood. Adipose tissue is now recognized as an important endocrine organ that secretes a variety of factors including adipokines. However, the regulation of expression pattern of these adipokines in both plasma and visceral white adipose tissue (WAT) in lean and fat pig is unclear. In the present study, we used two representative porcine breeds (Large White, LW; Meishan, MS) with contrasting backfat thickness and sexual maturity age. Using specific ELISA assays, we determined the plasma profile of eight adipokines, leptin, adiponectin, visfatin, apelin, chemerin, resistin, omentin and vaspin in LW and MS sows. By RT-qPCR and western-blot we also investigated the mRNA and protein levels of these adipokines and their cognate receptors (LEPR, ADIPOR1, ADIPOR2, CMKLR1, CCRL2, GPR1, APLNR, TLR4, ROR1, CAP1 and HSPA5) in the peri renal WAT, respectively. At both plasma and peri renal WAT level, we found that the amounts of leptin, chemerin, resistin and vaspin were higher whereas those of adiponectin and omentin were lower in MS than LW sows. Plasma and adipose tissue visfatin and apelin levels were not different between the two breeds. Moreover, we noted that the variations of peri renal WAT adipokines observed between MS and LW were similar at the protein and mRNA level except for chemerin and apelin suggesting post-transcriptional modifications for these two adipokines. Finally, among the eight adipokines studied, we showed that only the plasma concentrations of leptin and chemerin were positively and those of adiponectin, negatively associated with the thickness of fat and opposite correlation was found for the onset of puberty in both LW and MS animals. Taken together, these results support a potential involvement of adipokines in WAT regulation and its link with the onset of the puberty in sows.

Analysis of the chemerin and resistin adipokines in children and adolescents

OBJECTIVES

To compare the serum concentrations of adipokines resistin and chemerin in children and adolescents with eutrophic and overweight and to evaluate their relationship with anthropometric, biochemical, and blood pressure variables.

METHODS

a cross-sectional epidemiological study was conducted with 234 students enrolled in public elementary schools in the city of Juiz de Fora / MG. Anthropometric evaluation, biochemistry, and blood pressure measurement were performed. Statistical analyzes included the Student-t or Mann-Whitney tests, Pearson or Spearman correlation, used according to the distribution of the variables, and linear regression analysis, by means of the evaluation of the effect of the independent variables on the serum levels of chemerin and resistin, adjusted for age and sex. For the data analysis, SPSS® software version 21.0 and STATA® version 10.1 were used, assuming a significance level of 5%.

RESULTS

the concentrations of chemerin were higher in eutrophic individuals than in those with excess weight (p> 0.05). In contrast, levels of resistin were higher in the young with excess weight than in the eutrophic ones (p <0.05). In the multiple linear regression analysis, the levels of chemerin were associated with the values of resistin, systolic, and diastolic blood pressure. Resistance levels maintained association only with BMI and chemerin values.

CONCLUSION

the adipokines analyzed presented a distinct profile in the groups of children and adolescents with eutrophic and overweight.

Resistin levels are not associated with obesity in central precocious puberty

OBJECTIVE

To compare serum resistin concentrations between prepubertal girls with a BMI > 85th percentile and girls with precocious puberty (CPP) who have and have not undergone GnRH analog treatment.

PATIENTS AND METHODS

This is a cross-sectional study in girls with a BMI > 85th percentile and a median age of 8 years. We included 31 girls with CPP who did not receive treatment (CPPoT), 23 girls with CPP who were treated with leuprolide (CPPT), 22 prepubertal girls and 24 pubertal girls. Anthropometric data and the fasting plasma concentrations of lipids, glucose, insulin, and resistin were measured.

RESULTS

The z-BMI scores were similar among the groups (p = 0.344), and body fat percentage (BF%) was similar among CPPT, CPPoT and prepubertal girls (p = 0.151). Resistin and insulin levels were lower in girls with CPP (CPPT and CPPoT) than in prepubertal and pubertal girls (median resistin level: CPPT 11.8 pg/ml vs CPPoT 11 pg/ml vs prepubertal 16 pg/ml vs pubertal 16 pg/ml, p = 0.001; median insulin level: CPPT 10.7 μUI/mL vs CPPoT 10.2 μUI/mL vs prepubertal 14.4 μUI/mL vs pubertal 32 μUI/mL p = 0.02). ANCOVA analysis, after adjustments for pubertal stage, BF% and z-BMI, showed that CPP modifies resistin levels (F = 31.4; p = 0.0001) independently of these parameters (p < 0.05).

CONCLUSIONS

In the group of girls with overweight or obesity, the resistin level was lower in girls with CPP than in prepubertal and pubertal girls. More studies are needed to understand the role of resistin in CPP patients.

Comparative Proteome Analysis Reveals Lipid Metabolism-Related Protein Networks in Response to Rump Fat Mobilization

Altay is a typical fat-tailed sheep breed displaying the unique ability to rapidly mobilize fat, which is vital for maintaining a normal metabolism that facilitates its survival in lengthy winter conditions. However, the physiological, biochemical, and molecular mechanisms underlying fat mobilization remain to be elucidated. In this study, the monitoring of rump fat adipocyte sizes disclosed a positive correlation between cell size and fat deposition ability. In addition, we subjected sheep to persistent starvation to imitate the conditions that trigger rump fat mobilization and screened 112 differentially expressed proteins using the isobaric peptide labeling approach. Notably, increased secretion of leptin and adiponectin activated the key fat mobilization signaling pathways under persistent starvation conditions. Furthermore, the upregulation of resistin (RETN), heat-shock protein 72 (HSP72), and complement factor D (CFD) promoted lipolysis, whereas the downregulation of cell death-inducing DFFA-like effector C (CIDEC) inhibited lipid droplet fusion, and the increase in HSP72 and apolipoprotein AI (Apo-AI) levels activated the body’s stress mechanisms. The synergistic actions of the above hormones, genes, and signaling pathways form a molecular network that functions in improving the adaptability of Altay sheep to extreme environments. Our findings provide a reference for elucidating the complex molecular mechanisms underlying rump fat mobilization.

Cardiovascular risk biomarkers and metabolically unhealthy status in prepubertal children: Comparison of definitions

BACKGROUND AND AIMS

The early onset of cardio-metabolic abnormalities, known as metabolically unhealthy (MU) status, is highly associated with obesity and cardiovascular disease (CVD), as well as with increased morbidity and mortality later in life. Given the lack of a consensus MU classification for prepubertal children, we aimed to compare available MU definitions in terms of their association with CVD risk biomarkers.

METHODS AND RESULTS

A total of 930 prepubertal children (622 with overweight/obesity, 462 males) aged 5-10.9 years were recruited, anthropometric measures were taken and biomarkers were analyzed. Children were classified using eight MU definitions based on different cut-offs for blood pressure, triacylglycerides, high-density lipoprotein cholesterol, glucose and homeostasis model assessment for insulin resistance (HOMA-IR). MU prevalence in children with overweight/obesity ranged between 30% and 60% across definitions. Plasma concentrations of resistin, leptin, myeloperoxidase (MPO) and total plasminogen activator inhibitor 1 (tPAI-1) were higher, and those of adiponectin were lower, in MU compared to MH children with overweight/obesity. Linear regression analyses confirmed the contribution of MPO and tPAI-1 concentrations to MU status, with most significant results derived from definitions that use age and sex-specific criteria and that account for HOMA-IR.

CONCLUSION

Plasma concentrations of MPO and tPAI-1 are increased in prepubertal MU children irrespective of having normal-weight or overweight/obesity. Inclusion of age and sex-specific cut-offs for cardio-metabolic components as well as insulin resistance criteria increases the quality of MU definitions as seen by their stronger association with CVD biomarkers concentrations.

Early changes in adipokines from overweight to obesity in children and adolescents

OBJECTIVE

Childhood obesity has been associated with metabolic syndrome and cardiovascular diseases. This study aimed to compare plasma levels of traditional metabolic markers, adipokines and soluble tumor necrosis factor receptor type 1 (sTNFR1) in overweight, obese and lean children. We also assessed the relationships of these molecules with classical metabolic risk factors.

METHODS

This study included 104 children and adolescents, which were grouped as: lean (n=24), overweight (n=30), and obese subjects (n=50). They were subjected to anthropometrical, clinical and laboratorial measurements. All measurements were compared between groups. Correlation analyses were also performed to evaluate the association between clinical data, traditional metabolic markers, adipokines and sTNFR1.

RESULTS

Fasting glucose, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), LDL-cholesterol and triglycerides were comparable in lean, overweight and obese subjects. Plasma levels of sTNFR1 were similar in lean and overweight subjects, but significantly increased in obese group. Leptin, adiponectin and resistin levels did not differ when overweight were compared to obese subjects. However, all adipokines differed significantly when lean subjects were compared to overweight and obese individuals. Plasma levels of adiponectin were negatively correlated with body mass index (BMI), whereas leptin, resistin and sTNFR1 concentrations positively correlated with BMI.

CONCLUSION

Our results showed significant differences in circulating levels of the evaluated markers when lean, overweight and obese individuals were compared, suggesting that these biomarkers may change from lean to overweight and from overweight to obesity.

Concentrations of adipokines in children before and after hematopoietic stem cell transplantation

Adipokines have multiple effects, including regulation of glucose metabolism, cell proliferation, inflammation, and angiogenesis. The aim of the study was to determine plasma concentrations of adiponectin, apelin, leptin, and resistin as well as soluble leptin receptor in pediatric hematopoietic stem cell transplantation (HSCT). The expression of genes encoding the studied peptides was measured using microarray technique. Plasma concentrations of tested peptides were measured before and after oral glucose tolerance test in children treated with HSCT (n = 38) and in healthy controls (n = 26). The peptides were measured before HSCT (pre-HSCT group; n = 38) and after a median of 6 months after HSCT (post-HSCT group; n = 27 of 38 children treated with HSCT). In addition, measurements of fasting plasma glucose, insulin, lipids, and high-sensitivity C-reactive protein (hsCRP) were performed. In both HSCT groups, atherogenic lipid profile, low-grade systemic inflammation was observed. Leptin, adiponectin, and resistin also appear to be good markers of disease burden and low-grade systemic inflammation. Adipokines may be good markers of disease burden and may influence metabolic complications of HSCT. Future studies on larger groups of patients will explain if changes of the concentrations of leptin, adiponectin, and apelin observed in our study and confirmed by expression levels influence engraftment and reconstitution of cell lines.

Obesity-associated sympathetic overactivity in children and adolescents: the role of catecholamine resistance in lipid metabolism

BACKGROUND

Obesity in children and adolescents is characterized by chronic sympathetic overdrive and reduced epinephrine-stimulated lipolysis. This resistance to catecholamines occurs during the dynamic phase of fat accumulation. This review will focus on the relationship between sympathetic-adrenal activity and lipid metabolism, thereby highlighting the role of catecholamine resistance in the development of childhood obesity.

RESULTS AND CONCLUSIONS

Catecholamine resistance causes lipid accumulation in adipose tissue by reducing lipolysis, increasing lipogenesis and impeding free fatty acid (FFA) transportation. Exercise improves catecholamine resistance, as evidenced by attenuated systemic sympathetic activity, reduced circulating catecholamine levels and enhanced β-adrenergic receptor signaling. Insulin resistance is mostly a casual result rather than a cause of childhood obesity. Therefore, catecholamine resistance in childhood obesity may promote insulin signaling in adipose tissue, thereby increasing lipogenesis. This review outlines a series of evidence for the role of catecholamine resistance as an upstream mechanism leading to childhood obesity.

Adding anthropometric measures of regional adiposity to BMI improves prediction of cardiometabolic, inflammatory and adipokines profiles in youths: a cross-sectional study

BACKGROUND

Paediatric research analysing the relationship between the easy-to-use anthropometric measures for adiposity and cardiometabolic risk factors remains highly controversial in youth. Several studies suggest that only body mass index (BMI), a measure of relative weight, constitutes an accurate predictor, whereas others highlight the potential role of waist-to-hip ratio (WHR), waist circumference (Waist C), and waist-to-height ratio (WHtR). In this study, we examined the effectiveness of adding anthropometric measures of body fat distribution (Waist C Z Score, WHR Z Score and/or WHtR) to BMI Z Score to predict cardiometabolic risk factors in overweight and obese youth. We also examined the consistency of these associations with the "total fat mass + trunk/legs fat mass" and/or the "total fat mass + trunk fat mass" combinations, as assessed by dual energy X-ray absorptiometry (DXA), the gold standard measurement of body composition.

METHODS

Anthropometric and DXA measurements of total and regional adiposity, as well as a comprehensive assessment of cardiometabolic, inflammatory and adipokines profiles were performed in 203 overweight and obese 7-17 year-old youths from the Paediatrics Clinic, Centre Hospitalier de Luxembourg.

RESULTS

Adding only one anthropometric surrogate of regional fat to BMI Z Score improved the prediction of insulin resistance (WHR Z Score, R(2): 45.9%. Waist C Z Score, R(2): 45.5%), HDL-cholesterol (WHR Z Score, R(2): 9.6%. Waist C Z Score, R(2): 10.8%. WHtR, R(2): 6.5%), triglycerides (WHR Z Score, R(2): 11.7%. Waist C Z Score, R(2): 12.2%), adiponectin (WHR Z Score, R(2): 14.3%. Waist C Z Score, R(2): 17.7%), CRP (WHR Z Score, R(2): 18.2%. WHtR, R(2): 23.3%), systolic (WHtR, R(2): 22.4%), diastolic blood pressure (WHtR, R(2): 20%) and fibrinogen (WHtR, R(2): 21.8%). Moreover, WHR Z Score, Waist C Z Score and/or WHtR showed an independent significant contribution according to these models. These results were in line with the DXA findings.

CONCLUSIONS

Adding anthropometric measures of regional adiposity to BMI Z Score improves the prediction of cardiometabolic, inflammatory and adipokines profiles in youth.

Endocrine and Metabolic Effects of Adipose Tissue in Children and Adolescents

Adipose tissue is implicated in many endocrine and metabolic processes. Leptin was among the first identified adipose-secreted factors, which act in an auto-, para- and endocrine manner. Since leptin, many other adipose tissue factors were determined, some primarily secreted from the adipocytes, some from other cells of the adipose tissue.

So-called adipokines are not only involved in obesity and its complications, as are insulin resistance, type 2 diabetes and other components of the metabolic syndrome, but also in growth, reproduction, bone metabolism, immune response, cancer development and many other important biological processes. Research in the field of adipokines has revealed new insights into the physiological and pathophysiologal processes and opened new therapeutic possibilities. In the present article, a special emphasis is devoted to research in children and adolescents.

Human resistin and the RELM of Inflammation in diabesity

The initial discovery of resistin and resistin-like molecules (RELMs) in rodents suggested a role for these adipocytokines in molecular linkage of obesity, Type 2 Diabetes mellitus and metabolic syndrome. Since then, it became apparent that the story of resistin and RELMs was very much of mice and men. The putative role of this adipokine family evolved from that of a conveyor of insulin resistance in rodents to instigator of inflammatory processes in humans. Structural dissimilarity, variance in distribution profiles and a lack of corroborating evidence for functional similarities separate the biological functions of resistin in humans from that of rodents. Although present in gross visceral fat deposits in humans, resistin is a component of inflammation, being released from infiltrating white blood cells of the sub-clinical chronic low grade inflammatory response accompanying obesity, rather than from the adipocyte itself. This led researchers to further explore the functions of the resistin family of proteins in inflammatory-related conditions such as atherosclerosis, as well as in cancers such as endometrial and gastric cancers. Although elevated levels of resistin have been found in these conditions, whether it is causative or as a result of these conditions still remains to be determined.

Association of resistin polymorphisms with resistin levels and lipid profile in children

Previous research has found a correlation between resistin and lipid level variations. Polymorphisms in the resistin gene (RETN) could be involved in this relationship, but the results of the different studies are contradictory. The aim of this study was to examine the association between resistin and lipid levels, and to determine whether resistin polymorphisms are associated with resistin levels and lipid profile in prepubertal children and adolescents. The single nucleotide polymorphisms (SNPs) rs1862513 and rs10401670 were analyzed in 442 randomly selected 6- to 8-year-old children and 827 children aged 12-16 years. Anthropometric data were recorded. Lipid profile was determined using standard methods. Serum resistin levels were measured using a multiplexed bead immunoassay. Resistin polymorphisms were determined by TaqMan(®) allelic discrimination assays. A relationship was found between serum levels of resistin and the SNP rs10401670 in 6- to 8-year-old boys. SNP rs10401670 was also related to TC and LDL-cholesterol in 12- to 16-year-old boys and to HDL-C in 12- to 16-year-old girls. SNP rs1862513 was not related to any of the studied variables. Serum resistin levels were significantly and negatively associated with ApoAI levels in 12- to 16-year-old girls. A SNP in the 3'UTR region of RETN (rs10401670) is associated with resistin levels and lipid profile in children, showing different associations depending on age and gender.

Role of resistin in insulin resistance and obesity

Resistin is an adipose-derived hormone postulated to link adiposity to insulin resistance. Rodent animal experiments and in vitro experimental studies showed that resistin can induce insulin resistance, glucose and lipid metabolism disorders, and be closely related to metabolic syndrome. However, the specific mechanisms of action of resistin in humans are not clear. There is still controversy over the relationship between resistin and obesity. This review aims to elucidate the role of resistin in insulin resistance and discuss the relationship between resistin and obesity.