Inflammatory adipokines, high molecular weight adiponectin, and insulin resistance: a population-based survey in prepubertal schoolchildren

Cross-Sectional Analysis of IL-6, TNF-α, Adiponectin, Leptin, and Klotho Serum Levels in Relation to BMI Among Overweight and Obese Children Aged 10-14 in La Rioja, Spain

BACKGROUND

Childhood obesity is a major public health concern, being linked to an increased risk of metabolic disorders and cardiovascular disease. Even in childhood, obesity is associated with systemic low-grade inflammation, which is a critical factor in the development of atherosclerosis and a predictor of cardiovascular morbidity and mortality.

OBJECTIVES

To describe the prevalence of obesity and examine the relationship between IL-6, TNF-α, adiponectin, leptin, the leptin/adiponectin (L/A) ratio, and Klotho levels with BMI in children.

METHODS

This cross-sectional study included children aged 10-14 years from La Rioja, Spain. Participants were selected based on BMI criteria for overweight (85th-95th percentiles) and obesity (>95th percentile). Socio-demographic and anthropometric data and blood samples were collected and analyzed for IL-6, TNF-α, adiponectin, leptin, and Klotho.

RESULTS

A total of 340 participants were included, with 276 (81.2%) classified as normal weight and 64 (18.8%) as overweight or obese. Mean age was similar between groups (p = 0.40). Obesity was more prevalent in males (59.4%, p = 0.048). Obese participants had higher mean birth weight (p = 0.003), current height (p = 0.04), BMI (p < 0.0001), and abdominal circumference (p < 0.0001). BMI correlated positively with leptin (r = 0.54, p = 0.0008) and the L/A ratio (r = 0.40, p = 0.025), showing sex-specific differences.

CONCLUSIONS

This study underscores leptin and the L/A ratio as potential biomarkers of metabolic dysregulation in childhood obesity, particularly in females. Longitudinal studies are needed to confirm these findings and assess the clinical utility of these biomarkers in pediatric obesity management.

Nuts and seeds consumption impact on adolescent obesity: sex-specific associations from 2003 to 2018 National Health and Nutrition Examination Survey

The nutritional benefits and immunological advantages of consuming nuts and seeds are well-established. However, the link between nuts and seeds consumption and the susceptibility of being overweight or obese among adolescents is not clear. This study aims to explore this relationship in adolescents aged 12-19. Using a weighted multiple logistic regression model, we analysed data of the Food Patterns Equivalents Database and the U.S. National Health and Nutrition Examination Survey (NHANES) from 2003 to 2018. We found a significant association between nuts and seeds consumption and a reduced odds of being overweight or obese in females. Specifically, females who habitually consumed nuts and seeds had lower odds of being overweight or obese (OR = 0.55, 95% CI: 0.32-0.94). Additionally, we found an L-shaped relationship between nuts and seeds consumption and appropriate waist-to-height ratio in males. The findings suggest that nuts and seeds consumption may contribute to healthier physical development in adolescents.

The Impact of Physical Exercise on Obesity in a Cohort of Southern Italian Obese Children: Improvement in Cardiovascular Risk and Immune System Biomarkers

Background: Childhood obesity (CO) is a serious medical condition affecting approximately 120 million children and adolescents worldwide. It is characterized by a persistent inflammatory state with inflammatory markers overexpressed, which in turn leads to a higher cardiovascular risk. It is well known that physical exercise reduces the inflammatory state in obese children. In the present study, we evaluated various biochemical parameters in obese children performing physical exercise compared to a group of obese sedentary children. Hence, the objective is to identify a panel of biomarkers to prevent numerous obesity-related complications. Methods: We examined two populations: 44 sedentary obese children (OSe), recruited on 5 November 2018 from Santobono−Pausilipon Children’s Hospital, Naples (Italy) of age = 11 ± 3.3 and 30 obese children who practice sport (OSp) of age = 10 ± 2.5. We observed a significant variation in some biochemical parameters such as white blood cells, C-reactive protein (CRP), glycemia and insulinemia. Moreover, we determined the levels of interleukins, chemokines and defensins by ELISA assay. Results: Our results showed a reduction in serum level of glycemia (p-value < 0.001), neutrophils (p-value < 0.05) and CRP (p-value < 0.05), whereas no relevant variations have been reported in insulin levels. Moreover, we found a decrease in serum levels of PDGF-β (p-value < 0.05), IL-9 (p-value < 0.01), IL-6 (p-value < 0.0001), IL-8 (p-value < 0.0001), IP-10 (p-value < 0.01), Eotaxin (p-value < 0.0001) and GM-CSF (p-value < 0.01) in OSp population in comparison to OSe. At the same time, we did not observe any significant variation in serum levels of IL-1ra and IL-17 between the two populations. On the other hand, we found an increase in HNP-1 (p-value < 0.0001) and HBD1 (p-value < 0.01) in OSp if compared to OSe. Conclusions: This study shed light on the role of physical exercise on CO, demonstrating in our population that an early evaluation of some biochemical parameters could be an assumption to prescribe physical exercise in order to monitor and prevent childhood obesity and related disorders.

Exercise Outcomes in Childhood Obesity-Related Inflammation and Oxidative Status

Childhood obesity is identified as one of the major public health issues to increase the risk for cardiometabolic diseases and related complications in adulthood. The literature has supported inflammation and oxidative stress as the primary underlying mechanisms involved in the pathogenesis of obesity-related diseases. Epidemiological evidence consistently shows the benefits of physical activity in the improvement of obesity-mediated inflammation and oxidative stress status. In this narrative mini-review, the available scientific evidence on the potential effects of exercise in alleviating these susceptibilities in childhood obesity will be assessed.

Durability of Changes in Biomarkers of Cardiometabolic Disease: 1-Year Family-Based Intervention in Children with Obesity

Background: The sustainability of health benefits in response to lifestyle-based interventions remains unclear in children with overweight and obesity, and cardiometabolic disease (CMD). We determined the changes in novel biomarkers of CMD in a 1-year family-based intervention (FBI) program, during 6-month active monitoring phase and at 12-month follow-up. Methods: Children with an age-adjusted body mass index (BMI) percentile ≥85 (N = 130; age 8-11 years) were recruited for a 1-year (6-month monitored and 6-month unmonitored) randomized controlled FBI program. Anthropometry and selected biomarkers of CMD were measured in 87 participants, randomly allocated to intervention (INT) and education-only (EDU) groups, at baseline, immediately after a 6-month active intervention or control period, and at 12-month unmonitored follow-up. Results: Samples from 87 participants (age 10.00 ± 0.11 years and Tanner stage ≤3) with obesity (BMI%ile = 97.45 ± 0.15) were available. Overall intervention effect (between groups), was observed for total (T) and high molecular weight (HMW) adiponectin, ratio of total to HMW adiponectin, fibrinogen, and interleukin (IL)-6 (P < 0.05 for all). However, between-group beneficial changes after adjusting for baseline levels were limited to BMI percentile, T and HMW adiponectin and their ratio, IL-6, and fibrinogen (P < 0.05 for all) mainly during the 6-month period of monitored intervention. Changes in traditional risk factors such as lipids and triglycerides were inconsistent. During the 6-month follow-up period, the changes in biomarkers leveled-off, except for T and HMW adiponectin, IL-6, and fibrinogen that continued to show benefits (P < 0.05) from the 6- to 12-month follow-up. Conclusions: The FBI program beneficially altered novel biomarkers of CMD during the monitored intervention phase in school-age children with obesity, but they mostly moved back toward baseline during the unmonitored follow-up phase. The changes in novel biomarkers of CMD appear to be more sensitive compared to the traditional risk factors. The study implies the need for refinements in lifestyle-based approaches in the preservation of cardiovascular health and calls for robust biomarkers to monitor the changes. The study was registered at ClinicalTrials.gov (NCT01146314).

Plasma from obese children increases monocyte-endothelial adhesion and affects intracellular insulin signaling in cultured endothelial cells: Potential role of mTORC1-S6K1

Childhood obesity is characterized by the loss of vascular insulin sensitivity along with altered oxidant-antioxidant state and chronic inflammation, which play a key role in the onset of endothelial dysfunction. We previously demonstrated a reduced insulin-stimulated Nitric Oxide (NO) bioavailability in Human Umbilical Vein Endothelial cells (HUVECs) cultured with plasma from obese pre-pubertal children (OB) compared to those cultured with plasma of normal-weight children (CTRL). However, mechanisms underlying endothelial dysfunction in childhood obesity remains poorly understood. Hence, the present study aimed to better investigate these mechanisms, also considering a potential involvement of mammalian Target Of Rapamycin Complex1 (mTORC1)-ribosomal protein S6 Kinase beta1 (S6K1) pathway. OB-children (N = 32, age: 9.2 ± 1.7; BMI z-score: 2.72 ± 0.31) had higher fasting insulin levels and increased HOMA-IR than CTRL-children (N = 32, age: 8.8 ± 1.2; BMI z-score: 0.33 ± 0.75). In vitro, HUVECs exposed to OB-plasma exhibited significant increase in Reactive Oxygen Species (ROS) levels, higher vascular and intercellular adhesion molecules exposure, together with increased monocytes-endothelial interaction. This was associated with unbalanced pro- and anti-atherogenic endothelial insulin stimulated signaling pathways, as measured by increased Mitogen Activated Protein Kinase (MAPK) and decreased Insulin Receptor Substrate-1 (IRS-1)/protein kinase B (Akt)/ endothelial NO Synthase (eNOS) phosphorylation levels, together with augmented S6K1 activation. Interestingly, inhibition of mTORC1-S6K1 pathway using rapamycin significantly restored the IRS-1/Akt/eNOS activation, suggesting a feedback regulation of IRS-1/Akt signal through S6K1. Overall, our in vitro data shed light on new mechanisms underlying the onset of endothelial dysfunction in childhood obesity.

Pro-Inflammatory Diet Is Associated with Adiposity during Childhood and with Adipokines and Inflammatory Markers at 11 Years in Mexican Children

There is limited evidence about the inflammatory potential of diet in children. The aim of this study was to evaluate the association between the Children's Dietary Inflammatory Index (C-DII) from 5 to 11 years with adiposity and inflammatory biomarkers in Mexican children. We analyzed 726 children from a birth cohort study with complete dietary information and measurements to evaluate adiposity at 5, 7 and 11 y and 286 children with IL-6, hsCRP, leptin and adiponectin information at 11 y. C-DII trajectories were estimated using latent class linear mixed models. We used linear mixed models for adiposity and logistic and multinomial regression for biomarkers. In girls, each one-point increase in C-DII score was associated with greater adiposity (abdominal-circumference 0.41%, p = 0.03; skinfold-sum 1.76%, p = 0.01; and BMI Z-score 0.05, p = 0.01). At 11 y the C-DII was associated with greater leptin (34% ≥ 13.0 ng/mL, p = 0.03) and hsCRP concentrations (29% ≥ 3.00 mg/L, p = 0.06) and lower adiponectin/leptin ratio (75% < 2.45, p = 0.02). C-DII trajectory 3 in boys was associated with a 75.2% (p < 0.01) increase in leptin concentrations and a 37.9% decrease (p = 0.02) in the adiponectin/leptin ratio. This study suggests that the inflammatory potential of diet may influence adiposity in girls and the homeostasis of adipose tissue and chronic subclinical inflammation in 11-year-old children.

Association of Total and High Molecular Weight Adiponectin with Components of Metabolic Syndrome in Mexican Children

OBJECTIVE

Childhood obesity linked to metabolic alterations, tend to appear simultaneously with altered adipocytokines, suggesting a role in pathogenetic development. Low circulating level of total and high molecular weight (HMW) adiponectin have been associated with components of the metabolic syndrome (MetS) and could represent an independent risk factor with potential use as a biomarker. To examine the prevalence of MetS in Mexican school children and to investigate the association of total and HMW adiponectin levels with biochemical parameters related to MetS.

METHODS

The study included a population of boys and girls, from 8 to 11 years old. Anthropometric and biochemical parameters were evaluated according to weight and MetS status. A correlation analysis was fitted to establish an association between adiponectin concentrations and metabolic indicators.

RESULTS

One-hundred and fifty five children participated (59.4% females) from 8-11 years of age. The prevalence of MetS was of 10.3%. Impaired biochemical parameters, including total and HMW adiponectin, were associated with obesity. The adiponectin level was significantly lower in MetS than in non-MetS subjects (4.5 vs. 5.4 μg/mL). Total- but not HMW adiponectin concentration was negatively correlated with blood pressure, fasting insulin, fasting blood sugar and Homeostatic Model Assessment for Insulin Resistance.

CONCLUSION

In young children, the total adiponectin level is associated with impaired biochemical parameters of carbohydrate metabolism and could be an excellent early predictor of metabolic complications.

Fibroblast Growth Factor 21, Adiponectin, and Irisin as Markers of Unfavorable Metabolic Features in 12-Year-Old Children

CONTEXT

Among cytokines, fibroblast growth factor 21 (FGF21), adiponectin (Adn), and irisin have been considered potential biomarkers for insulin sensitivity (IS).

OBJECTIVE

We evaluated whether serum FGF21, Adn, and irisin associate with markers of IS and serum lipids in 12-year-old children.

DESIGN PARTICIPANTS AND MAIN OUTCOME MEASURES

This cohort study included 192 12-year-old children (109 girls). Seventy-eight of them had been born appropriate for gestational age (AGA), 70 small for gestational age (SGA), and 44 from preeclamptic pregnancies (PREs) as AGA. Fasting serum FGF21, Adn, irisin, lipids, inflammatory markers, and IS markers were measured. Quantitative insulin sensitivity check index (QUICKI) was calculated.

RESULTS

The means of serum FGF21, high molecular weight (HMW) Adn, and irisin did not differ between the sexes or between the SGA, AGA, and PRE children. In the whole study population, FGF21 associated positively with irisin and uric acid and negatively with leptin and high-density lipoprotein cholesterol (HDL-C). HMW Adn associated positively with total Adn, HDL-C, leptin, and SHBG. Apart from FGF21, irisin associated positively with insulin, high-sensitivity C-reactive protein, γ-glutamyltransferase, and triglycerides, and negatively with QUICKI, SHBG, and IGF binding protein-1. In multivariate regression analyses, irisin predicted lower IS and HMW Adn predicted higher HDL-C body mass index-independently, whereas FGF21 had no independent contribution to IS or lipid variables.

CONCLUSION

In 12-year-old children, serum irisin was associated with markers reflecting reduced IS. HMW Adn predicted HDL-C, whereas FGF21 did not contribute to IS or lipid parameters in multivariate regression analyses.

Higher adiponectin concentrations are associated with reduced metabolic syndrome risk independently of weight status in Brazilian adolescents

OBJECTIVE

To evaluate the association between adiponectin concentrations and metabolic syndrome (MetS) risk and to investigate if this association is independent of weight status in adolescents.

METHODS

Adiponectin concentrations and MetS risk were assessed in 4546 Brazilian adolescents (12-17 years old) enrolled in The Study of Cardiovascular Risks in Adolescents ("ERICA"), a cross-sectional multicenter study in Brazil. For analyses, adiponectin was categorized in sex and age-specific quartiles and MetS risk was expressed as a continuous score, calculated as the average of the standardized values (z-score) of the five MetS components. Multiple linear regression models were used to investigate the association between the quartiles of adiponectin and MetS risk.

RESULTS

Adiponectin was inversely associated with waist circumference and log-transformed triglycerides, and positively associated with HDL-c. We also observed an inverse association between adiponectin concentrations and MetS risk. After adjustment for sociodemographic variables, physical activity, skipping breakfast and body mass index (BMI), higher quartiles of adiponectin remained inversely associated with waist circumference and MetS risk. A direct association between adiponectin and HDL-c was also observed. In further analysis, the sample was stratified by weight status and an inverse association between quartiles of adiponectin and MetS risk was observed in both normal weight and overweight/obese adolescents.

CONCLUSION

Higher adiponectin concentrations were independently and inverse associated with MetS risk in Brazilian adolescents, even after adjusting for BMI. These results were similar in normal weight and overweight/obese adolescents, suggesting that adiponectin may play a role in early development of MetS.

The phosphodiesterase type 4 inhibitor roflumilast suppresses inflammation to improve diabetic bladder dysfunction rats

PURPOSE

To demonstrate that phosphodiesterase type 4 (PDE4) inhibitors could potentially treat diabetic bladder dysfunction (DBD) through modulation of the systemic inflammatory response.

METHODS

In this 6-week study, 60 female Sprague-Dawley rats were divided into three groups: (i) vehicle-treated control rats; (ii) vehicle-treated streptozocin (STZ)-injected rats; and (iii) roflumilast-treated STZ-injected rats. Oral roflumilast (5 mg/kg/day) was administered during the last 4 weeks of STZ injection to induce diabetes in the test group. At 6 weeks, a urodynamic study was performed in each group. The expression of nuclear factor kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and IL-1β in detrusor smooth muscle (DSM) was analyzed using quantitative reverse transcription-polymerase chain reaction and Western blotting.

RESULTS

A significant decrease in bodyweight and significant increases in bladder weight and blood glucose level were observed in the diabetic rats and were not ameliorated by roflumilast treatment. Cystometry showed the increased bladder capacity, voiding volume, residual urine volume, and voiding interval in the diabetic rats and the prevention of these changes by roflumilast. These changes were accompanied by significantly enhanced expression of NF-κB, TNF-α, IL-6, and IL-1β in DSM tissue from diabetic rats. Furthermore, roflumilast attenuated the expression of inflammatory factors in DSM tissue.

CONCLUSIONS

Oral treatment with roflumilast in diabetic rats improves bladder function and inhibits the expression of inflammatory factors in DSM tissue, indicating that PDE4 is a potential therapeutic target for DBD.

Impact of a group-based treatment program on adipocytokines, oxidative status, inflammatory cytokines and arterial stiffness in obese children and adolescents

Background Dysregulation of adipocytokines, inflammatory cytokines and oxidative stress are associated with the pathogenesis of obesity-related complications. This study aimed to evaluate the effect of a group-based lifestyle modification program on adipocytokines, inflammatory cytokines, oxidative status and arterial stiffness in obese youth. Methods A 1-year weight-reduction program was conducted. The program consisted of initial hospitalization and five outpatient group-based sessions held at 1, 2, 3, 6 and 9 months. Pre- and post-intervention measurements included anthropometric data, blood tests, body composition and brachial-ankle pulse wave velocity (ba-PWV). Results A total of 126 obese youths were recruited, and 115 of those completed the study. Twenty-four participants had increased percentage weight for height at the end of the study (group A), 30 had minimal reduction (group B) and 61 had substantial reduction (group C). Lean mass significantly increased in all three groups (all p<0.001). A significant decrease in leptin (group A, p=0.021; group B, p=0.005; group C, p<0.001), interleukin-6 (IL-6) (group A, p=0.019; group B, p=0.004; group C, p<0.001) and ba-PWV (group A, p=0.031; group B, p=0.015; group C, p<0.001) was also observed. No significant change in the oxidative status was found among the groups. Reduction in ba-PWV was correlated with decreases in plasma malondialdehyde (pMDA) (r=0.233, p=0.036) and homeostasis model assessment of insulin resistance (HOMA-IR) (r=0.253, p=0.025). Conclusions A group-based healthy lifestyle program for obese youths had beneficial effects on adipocytokines, inflammatory cytokines and arterial stiffness. Participants without change in weight status also benefited. These improvements may reduce the risk of obese youths developing atherosclerosis.

Comparison of body composition and adipokine levels between thin and normal-weight prepubertal children

OBJECTIVE

Thinness can have substantial consequences for child development and health. Adipokines, including leptin and adiponectin, play a significant role in the regulation of important metabolic functions. The aim of this study was to investigate associations between body composition and serum leptin and adiponectin levels in thin and normal-weight children.

METHODS

The authors examined 100 healthy prepubertal children, who were divided into two subgroups: thin (n=50) and normal-weight children (n=50). Body composition was assessed by dual-energy X-ray absorptiometry. Serum concentrations of adipokines were determined by immunoenzymatic assays.

RESULTS

Thin children had a similar body height but significantly lower (p<0.0001) body weight, body mass index, fat mass, lean mass, and bone mineral content compared with normal-weight children. Serum concentrations of leptin were about 2-fold lower (p<0.0001) in thin vs. normal-weight subjects. Serum levels of total adiponectin, adiponectin multimers, and soluble leptin receptor (sOB-R) were similar in both groups. The leptin/soluble leptin receptor ratio and leptin/adiponectin ratios were lower (p<0.0001) in thin vs. normal-weight children. In both groups of children, it was found that body composition parameters were positively related with leptin but not with adiponectin levels. Additionally, bone mineral content was positively related with body mass index, fat mass, lean mass, and leptin level in thin and normal-weight children.

CONCLUSIONS

Prepubertal thin children have disturbances in body composition and adipokine profile. Early recognition of thinness and determination of body composition parameters and adipokine levels can be useful in medical and nutritional care of thin children for the optimization of bone mineral accrual.

Fetuin-A, adiposity-linked insulin resistance and responsiveness to an educational-based weight excess reduction program: a population-based survey in prepubertal schoolchildren

The secreted hepatokine fetuin-A emerges as an independent predictor of type 2 diabetes in adulthood. The overall aims of this study were: (1) to investigate the associations of fetuin-A with adiposity and insulin resistance, as well as its relationship with adipokines, in prepubertal children, and, (2) to evaluate whether, in prepubertal obesity, serum fetuin-A levels may either change or predict the responsiveness to an educational-based weight excess reduction program. We studied 200 prepubertal children (boys/girls: 89/111; Tanner stage 1; age: 5-13 years), included in a cohort of 44,231 adolescents who participated in an extensive Italian school-based survey. According to Cole's criteria, 100 individuals were lean (boys/girls: 57/43) and 100 obese (boys/girls: 54/46). A subset of 53 obese individuals (boys/girls: 28/25; age: 6-12 years) were also evaluated after a weight excess reduction program. Serum fetuin-A, leptin, total and high molecular weight adiponectin levels, as well as homeostasis model assessment of insulin resistance were assessed. When compared with lean, obese children exhibited higher ( p < 0.0001) fetuin-A concentrations, without differences between sex. Fetuin-A was positively associated with adiposity, homeostasis model assessment of insulin resistance, and leptin levels. In multivariate analysis, the associations between fetuin-A and leptin or homeostasis model assessment of insulin resistance lost the significance after adjustment for BMI _Z-score, which, in turn, represented an independent determinant of fetuin-A (R ²_adj 0.327; p < 0.0001). Notably, after weight excess reduction program, fetuin-A levels dropped ( p < 0.0001 vs. basal). Interestingly, no significant differences of fetuin-A concentrations between responders and no responders were found. In prepubertal children, fetuin-A represents an early marker of adiposity, and its reduction after lifestyle intervention may partly contribute to the beneficial effects of weight excess reduction program.

Association between abdominal fat distribution, adipocytokines and metabolic alterations in obese low-birth-weight children

BACKGROUND

In addition to obesity, low birth weight (LBW) has been proposed as another independent risk factor associated with cardiovascular disease and type 2 diabetes mellitus.

OBJECTIVE

This study aimed to evaluate the influence of birth weight on abdominal fat distribution, adipocytokine levels and associated metabolic alterations in obese children.

METHODS

A cross-sectional study was conducted in 92 children. Children were divided into three groups according to their body mass index and birth weight. Glucose and insulin (0 and 120 min), lipid profile and adipocytokines were measured. Abdominal fat distribution was assessed by magnetic resonance imaging.

RESULTS

Obese LBW children had higher fasting glucose (P = 0.054) and insulin (P < 0.001), and 120 min glucose (P < 0.001) and insulin levels (P < 0.001), such as increased HOMA-IR (homeostasis model assessment of insulin resistance index) (P < 0.001). Obesity and LBW were associated with lower concentrations of high molecular weight (HMW) adiponectin (-2.38 [IC 95% -4.27; -0.42, P = 0.018]) and higher subcutaneous adipose tissue (SAT) (28.05 [IC 95% 0.40; 55.7, P = 0.047]) compared with NBW obese children, independent of age or sex.

CONCLUSIONS

LBW in obese children is associated with lower HMW adiponectin, increased insulin resistance and greater SAT.

Adiposity trajectory and its associations with plasma adipokine levels in children and adolescents-A prospective cohort study

OBJECTIVE

This study aimed to examine the associations of longitudinal adiposity measures with two adipokines, leptin and adiponectin, and their ratio in children and adolescents.

METHODS

A total of 953 children and adolescents participated in a 6-year longitudinal study. Body mass index (BMI), percentage body fat (%BF), and fat mass index (FMI) were used to assess adiposity status.

RESULTS

After adjusting for possible confounders, our regression models revealed that BMI, %BF, and FMI, in both the baseline and follow-up surveys were independently associated with a higher level of leptin and the leptin/adiponectin ratio at the follow-up survey, whereas the significant association with adiponectin only partly existed in adiposity measures at the follow-up visit. Moreover, the longitudinal change in adiposity measures was found to be a significant predictor for follow-up plasma adipokine levels. Compared with the low→low group, the medium→medium group, up-trend group, and high→high group all showed a significantly increased level of leptin and leptin/adiponectin ratio. The up-trend group and high→high group also had significantly decreased adiponectin levels.

CONCLUSIONS

These findings highlight the importance of adiposity surveillance and the utility of adipokines as biomarkers for adverse metabolic consequences of childhood adiposity.

Temporal relationships between adipocytokines and diabetes risk in Hispanic adolescents with obesity

OBJECTIVE

Circulating cytokines are frequently cited as contributors to insulin resistance in children with obesity. This study examined whether circulating adipocytokines, independent of adiposity, predicted pubertal changes in insulin sensitivity (SI), insulin secretion (AIR), and β-cell function in high-risk adolescents.

METHODS

158 Hispanic adolescents with overweight or obesity were followed for a median of 4 years. Adipocytokines were measured using Luminex technology. SI, AIR, and the disposition index were derived from an intravenous glucose tolerance test and minimal modeling. Total fat mass was measured by DXA and visceral adipose tissue (VAT) by MRI.

RESULTS

Surprisingly, mean IL-8, IL-1β, IL-6, and TNF-α decreased between 5% and 6.5% per year from baseline (P < 0.001). Despite the general temporal trends, gaining 1-SD of VAT was associated with a 2% and 5% increase in MCP-1 and IL-8 (P < 0.05). In addition, a 1-SD higher MCP-1 or IL-6 concentration at baseline was associated with a 16% and 21% greater decline in SI during puberty vs. prepuberty (P < 0.05).

CONCLUSIONS

Several adipocytokines decreased during adolescence and were weakly associated with VAT and lower SI during puberty. Circulating adipocytokines have relatively limited associations with pubertal changes in diabetes risk; however, the consistent findings with MCP-1 warrant further investigation.

Role of Macrophage Migration Inhibitory Factor in Obesity, Insulin Resistance, Type 2 Diabetes, and Associated Hepatic Co-Morbidities: A Comprehensive Review of Human and Rodent Studies

Obesity is associated with a chronic low-grade inflammatory state that drives the ­development of obesity-related co-morbidities such as insulin resistance/type 2 diabetes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular disease. This metabolic inflammation is thought to originate in the adipose tissue, which becomes inflamed and insulin resistant when it is no longer able to expand in response to excess caloric and nutrient intake. The production of inflammatory mediators by dysfunctional adipose tissue is thought to drive the development of more complex forms of disease such as type 2 diabetes and NAFLD. An important factor that may contribute to metabolic inflammation is the cytokine macrophage migration inhibitory factor (MIF). Increasing evidence suggests that MIF is released by adipose tissue in obesity and that it is also involved in metabolic and inflammatory processes that underlie the development of obesity-related pathologies. This review provides a comprehensive summary of our current knowledge on the role of MIF in obesity, its production by adipose tissue, and its involvement in the development of insulin resistance, type 2 diabetes, and NAFLD. We discuss the main findings from recent clinical studies in obese subjects and weight-loss intervention studies as well as results from clinical studies in patients with insulin resistance and type 2 diabetes. Furthermore, we summarize findings from experimental disease models studying the contribution of MIF in obesity and insulin resistance, type 2 diabetes, and hepatic lipid accumulation and fibrosis. Although many of the findings support a pro-inflammatory role of MIF in disease development, recent reports also provide indications that MIF may exert protective effects under certain conditions.

Comparison of Serum Adipocytokine Levels according to Metabolic Health and Obesity Status

BACKGROUND

Metabolic health is an emerging concept that is highly correlated with various metabolic complications, and adipocytokines have been causally linked to a wide range of metabolic diseases. Thus, this study compared serum adipocytokine levels according to metabolic health and obesity status.

METHODS

Four hundred and fifty-six nondiabetic subjects (mean age, 40.5 years) were categorized into four groups according to metabolic health and obesity status: metabolically healthy nonobese (MHNO), metabolically healthy obese (MHO), metabolically unhealthy nonobese (MUHNO), and metabolically unhealthy obese (MUHO). Being metabolically healthy was defined as the presence of fewer than two of the following five metabolic abnormalities: high blood pressure, high fasting blood glucose, high triglyceride, low high density lipoprotein cholesterol, and being in the highest decile of the homeostatic model assessment of insulin resistance index. Obesity status was assessed using body mass index (BMI), with obesity defined as a BMI higher than 25 kg/m². Levels of serum interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor α (TNF-α), and adipocyte fatty acid binding protein (A-FABP) were also evaluated.

RESULTS

Of the 456 subjects, 247 (54.2%) were in the MHNO group, 66 (14.5%) were in the MHO group, 66 (14.5%) were in the MUHNO group, and 77 (16.9%) were in the MUHO group. There were no significant differences in IL-6 or MCP-1 levels among the groups, but levels of TNF-α and A-FABP were significantly higher in the MUHNO group compared to the MHNO group.

CONCLUSION

High TNF-α and A-FABP levels are significantly associated with metabolically unhealthiness in nonobese Korean individuals.

Adipokines, vascular wall, and cardiovascular disease: a focused overview of the role of adipokines in the pathophysiology of cardiovascular disease

Epidemiological evidence has shown that abdominal obesity is closely associated with the development of cardiovascular (CV) disease, suggesting that it might be considered as an independent CV risk factor. However, the pathophysiological mechanisms responsible for the association between these 2 clinical entities remain largely unknown. Adipocytes are considered able to produce and secrete chemical mediators known as "adipokines" that may exert several biological actions, including those on heart and vessels. Of interest, a different adipokine profile can be observed in the plasma of patients with obesity or metabolic syndrome compared with healthy controls. We consider the main adipokines, focusing on their effects on the vascular wall and analyzing their role in CV pathophysiology.

Adipose tissue chromium and vanadium disbalance in high-fat fed Wistar rats

The primary objective of the current study is to investigate the relationship between adipose tissue chromium and vanadium content and adipose tissue dysfunction in a model of diet-induced obesity. A total of 26 female Wistar rats were fed either standard or high-fat diet (31.6% of fat from total caloric content) for 3 months. High-fat-feeding resulted in 21 and 33% decrease in adipose tissue chromium and vanadium content, respectively. No change was seen in hair chromium or vanadium levels. Statistical analysis revealed a significant inverse correlation of adipose tissue Cr and V with animal morphometric parameters and adipocyte size. Significant inverse dependence was observed between adipose tissue Cr and V and serum leptin and proinflammatory cytokines' levels. At the same time, adipose tissue Cr and V levels were characterized by positive correlation between serum adiponectin and adiponectin/leptin ratio. Adipose tissue Cr and V were inversely correlated (p<0.05) with insulin and homeostatic model assessment insulin resistance index (HOMA-IR) levels. Cr and V concentrations were not correlated with serum glucose in either high-fat fed or control rats; however, both serum glucose and HOMA-IR levels were significantly higher in high-fat fed, compared to control, rats. The results allow to hypothesize that impairment of adipose tissue Cr and V content plays a certain role in the development of adipose tissue endocrine dysfunction in obesity.

Adiponectin and markers of metabolic syndrome in obese children and adolescents: impact of 8-mo regular physical exercise program

BACKGROUND

Adiponectin circulates as low-, medium-, and high-molecular-weight multimers (LMW, MMW, and HMW) and influences lipid profile and insulin resistance (IR), HMW being considered as the most biologically active form. We aimed to study the relation between adiponectin and markers of metabolic syndrome (MS) in pediatric obesity, and the impact of physical exercise.

METHODS

The study consisted of a cross-sectional part and an 8-mo physical exercise program. Lipid profile, insulin, glucose, C-reactive protein (CRP), total adiponectin (TA), and homeostasis model assessment IR (HOMA-IR) were measured. Adiponectin multimers were studied in a prepubertal group.

RESULTS

Obesity is associated with increased dyslipidemia, IR, and inflammation. TA is correlated inversely with adiposity, triglycerides, HOMA-IR, and CRP, and positively with high-density lipoprotein cholesterol (HDLc)/total cholesterol (TC) ratio. HMW mimicked TA associations. The intervention program led to a reduction of TC, low-density lipoprotein cholesterol (LDLc), insulin, HOMA-IR, and trunk percentage of fat, and an increase of HDLc/TC ratio, in the obese group. BMI improvements prevented adiponectin reduction and correlated with increments in HMW and MMW.

CONCLUSION

Obesity-related increase in MS features might be linked to lower adiponectin. HMW and MMW were the multimers that most explained the MS features. The intervention program improved the lipid profile and IR, and prevented the reduction of adiponectin.

Does visceral adiposity index signify early metabolic risk in children and adolescents?: association with insulin resistance, adipokines, and subclinical inflammation

BACKGROUND

Visceral adiposity index (VAI) is a novel gender-specific index based on waist circumference (WC), BMI, and lipid parameters. Although VAI does not actually estimate visceral adiposity, it accurately reflects visceral fat function and insulin resistance. This index has not been studied in children thus far. This study aims to fill this gap.

METHODS

In a cohort of Saudi children and adolescents, anthropometric measurements and metabolic/hormonal profile were obtained.

RESULTS

A total of 543 subjects, 292 of whom were boys, were included (mean age: 11.9 ± 3.3 y; BMI: 19.8 ± 5.6 kg/m(2)). In all subjects, VAI was inferior to BMI and WC regarding its correlations with adiponectin, leptin, insulin resistance (homeostasis model of assessment-insulin resistance (HOMA-IR)), C-reactive protein (CRP) level, and systolic blood pressure, but it exhibited a stronger association with glucose in boys (r = 0.23; P < 0.01). In stepwise multivariate analyses, only BMI was consistent as an independent predictor of adiponectin, leptin, HOMA-IR, and CRP. VAI was the only index independently associated with glucose.

CONCLUSION

Although VAI is related to glucose in children, it seems to be inferior to BMI in terms of association with insulin resistance, adipokines, and subclinical inflammation. Until specific studies can be performed in children, VAI should be extrapolated with caution in this age range.

Associations between two single nucleotide polymorphisms of the adiponectin gene, its circulating concentrations and cardiometabolic risk factors in prepubertal children with and without abdominal obesity

BACKGROUND

The adiponectin gene has been identified as a susceptibility locus for metabolic syndrome, diabetes and cardiovascular disease.

AIM

To examine the influence of two single nucleotide polymorphisms (SNPs) of this gene (+276G>T and +45T>G) on circulating adiponectin concentrations, and to evaluate their relationship with adiposity and cardiometabolic risk factors in prepubertal children with and without abdominal obesity.

MATERIAL AND METHODS

168 children (78M, 6-10 yr) were examined, divided into three groups based on waist circumference (WC). Auxological and biochemical parameters were measured by standard procedures. Adiponectin SNPs were genotyped using TaqMan allelic discrimination assays.

RESULTS

Adiponectin concentration correlated inversely with measures of adiposity (rBMIz-score=-0.211, pBMIz-score=0.007; rwc=-0.210, pwc=0.008; rwc/height=-0.215, pwc/height=0.006), and was significantly influenced by blood glucose, insulin and systolic blood pressure (SBP). The +276T-allele carriers had higher SBP and diastolic BP compared to GG-homozygotes (p<0.05), and expressed higher obesity-related measures and lower adiponectin concentrations. As to the +45T>G SNP, the GGsubject had higher total cholesterol and LDL-C concentrations compared to the T-allele carriers (p<0.05), showing worse obesity measures, higher triglyceride, glucose and insulin and lower serum adiponectin values.

CONCLUSION

Genetic variants of the adiponectin gene had an impact on adiposity, adiponectin concentrations and some cardiometabolic variables among prepubertal children.

Hemin therapy suppresses inflammation and retroperitoneal adipocyte hypertrophy to improve glucose metabolism in obese rats co-morbid with insulin-resistant type-2 diabetes

AIM

Visceral adiposity and impaired glucose metabolism are common patho-physiological features in patients co-morbid with obesity and type-2 diabetes. We investigated the effects of the heme-oxygenase (HO) inducer hemin and the HO blocker stannous-mesoporphyrin (SnMP) on glucose metabolism, adipocyte hypertrophy and pro-inflammatory cytokines/mediators in Zucker diabetic fatty (ZDF) rats, a model characterized by obesity and type-2 diabetes.

METHODS

Histological, morphological/morphometrical, Western immunoblotting, enzyme immunoassay, ELISA and spectrophotometric analysis were used.

RESULTS

Treatment with hemin enhanced HO-1, HO activity and cGMP, but suppressed retroperitoneal adiposity and abated the elevated levels of macrophage-chemoattractant protein-1 (MCP-1), ICAM-1, tumour necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), IL-1β, NF-κB, c-Jun-NH2-terminal-kinase (JNK) and activating-protein (AP-1), with parallel reduction of adipocyte hypertrophy. Correspondingly, important proteins of lipid metabolism and insulin-signalling such as lipoprotein lipase (LPL), insulin-receptor substrate-1 (IRS-1), GLUT4, PKB/Akt, adiponectin, the insulin-sensitizing and anti-inflammatory protein and adenosine-monophosphate-activated protein kinase (AMPK) were significantly enhanced in hemin-treated ZDF rats.

CONCLUSION

Elevated retroperitoneal adiposity and the high levels of MCP-1, ICAM-1, TNF-α, IL-6, IL-1β, NF-κB, JNK and AP-1 in untreated ZDF are patho-physiological factors that exacerbate inflammatory insults, aggravate adipocyte hypertrophy, with corresponding reduction of adiponectin and deregulation of insulin-signalling and lipid metabolism. Therefore, the suppression of MCP-1, ICAM-1, TNF-α, IL-6, IL-1β, NF-κB, JNK, AP-1 and adipocyte hypertrophy, with the associated enhancement of LPL, adiponectin, AMPK, IRS-1, GLUT4, PKB/Akt and cGMP in hemin-treated ZDF are among the multifaceted mechanisms by which the HO system combats inflammation to potentiate insulin signalling and improve glucose and lipid metabolism. Thus, HO inducers may be explored in the search of novel remedies against the co-morbidities of obesity, dysfunctional lipid metabolism and impaired glucose metabolism.

Using snacks high in fat and protein to improve glucoregulatory function in adolescent male marmosets (Callithrix jacchus)

The common marmoset (Callithrix jacchus), a laboratory nonhuman primate, is a well-known model of several human diseases and conditions, but the nutritional needs of these animals are not fully understood. Here we describe a 4-mo controlled study in which we increased the dietary fat and protein of subadult male common marmosets by using healthy snacks. Six male marmosets received their normal diet (control), and an additional 6 were given their normal diet supplemented daily with a 14-kcal snack. Cashews and waxworms were used as the snack, given their high-fat content. Although body weight did not differ between the 2 groups, only control male marmosets showed increased chest circumferences over the course of the study. Glucoregulatory function remained consistent in the snack-fed marmosets, whereas control animals had progressed toward higher insulin. Other indices of glucoregulation indicated significant differences in adiponectin and the cortisol:cortisone ratio between the 2 groups, but no differences in lipid concentration were detected. Therefore, the most notable difference attributable to the snack feeding was improved glucoregulation. Because the snacks we used had a high proportion of unsaturated compared with saturated fat, we suggest that these healthy high-fat-high-protein snacks provide an important contribution to the nutrition of this laboratory species. This study also demonstrates the utility of marmosets as a model for understanding the implications of dietary fats in humans.

Changes in plasma adipokines in prepubertal children with a history of extrauterine growth restriction

OBJECTIVE

Because nutritional support in perinatal life has been associated with metabolic programming, children with a history of extrauterine growth restriction (EUGR) might display alterations in the adipocyte and in the secretion of adipokines. The aim of this study was to assess adiponectin, resistin, and leptin concentrations in prepubertal children with a history of EUGR, and to determine the potential correlation between these adipokines and metabolic parameters.

METHODS

This case-control study sample included 38 prepubertal children with a history of EUGR and a control group of 123 healthy children of similar age and sex. Anthropometric measures and blood pressure were assessed. Biochemical markers and blood adipokine concentrations (adiponectin, resistin, and leptin) were evaluated.

RESULTS

Adiponectin concentration was significantly lower in the EUGR group compared with controls (EUGR: 11.49 ± 6.07 versus control: 25.72 ± 10.13 μg/mL), and resistin concentration was higher (EUGR: 20332.95 ± 6401.25 versus control: 8056.31 ± 3823.63 pg/mL), even after adjustment for gestational age, weight, and size at birth. Systolic blood pressure was associated with adipokines concentrations in the EUGR group (P < 0.001). In EUGR children adiponectin was associated with high-density lipoprotein cholesterol (P = 0.042), whereas resistin was associated with carbohydrate metabolism parameters (P < 0.001).

CONCLUSIONS

Early postnatal malnutrition in EUGR children could program adipose tissue. Plasma adipokines can be measured in childhood to identify precocious changes that may be associated with a higher risk for metabolic syndrome or cardiovascular disease later in life.

Proinflammatory cytokines, adiponectin, and increased risk of primary cardiovascular events in diabetic patients with or without renal dysfunction: results from the ESTHER study

OBJECTIVE

Inflammatory processes contribute to both diabetes and cardiovascular risk. We wanted to investigate whether circulating concentrations of proinflammatory immune mediators and adiponectin in diabetic patients are associated with incident cardiovascular events.

RESEARCH DESIGN AND METHODS

In 1,038 participants with diabetes of the population-based ESTHER study, of whom 326 showed signs of renal dysfunction, Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs for the association of increasing concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), IL-18, macrophage migration inhibitory factor (MIF), adiponectin, and leptin with cardiovascular events (myocardial infarction, stroke, or fatal cardiovascular event) during a follow-up period of 8 years.

RESULTS

During follow-up, 161 subjects with diabetes experienced a primary cardiovascular event. Proinflammatory markers were not associated with a higher risk for primary cardiovascular events in the total study population after adjustment for multiple confounders. However, IL-6 and MIF were associated with cardiovascular events in subjects with renal dysfunction (HR for the comparison of top vs. bottom tertile 1.98 [95% CI 1.12-3.52], P [trend] = 0.10 for IL-6; 1.48 [0.87-2.51], P [trend] = 0.04 for MIF). Adiponectin levels were associated with cardiovascular events in the total population (1.48 [1.01-2.21], P [trend] = 0.03), and the association was even more pronounced in the subgroup with renal dysfunction (1.97 [1.08-3.57], P [trend] = 0.02).

CONCLUSIONS

In particular, the absence of an association between CRP and a U-shaped association of adiponectin levels with incident cardiovascular events show that associations between circulating immune mediators and cardiovascular risk differ between diabetic patients and subjects of the general population.

Adiponectin multimers, body weight and markers of cardiovascular risk in adolescence: Northern Ireland Young Hearts Project

BACKGROUND

Research examining the relationship between adiponectin (AN) isoforms, body weight and cardiovascular (CV) risk factors is limited, particularly in younger populations.

OBJECTIVES

To investigate the inter-relationships between AN isoforms and CV risk factors, and their dependence on body weight status, in adolescents.

DESIGN

Blood samples from 92 obese, 92 overweight and 92 normal weight age- and sex-matched adolescents were analysed for traditional cardiovascular disease (CVD) risk biomarkers and also total, high molecular weight (HMW), medium and low molecular weight (LMW) AN.

RESULTS

A significant inverse association was observed between total and HMW AN and waist-hip ratio (P=0.015, P=0.006, respectively), triglycerides (P=0.003, P=0.003, respectively) and systolic blood pressure (P=0.012, P=0.024, respectively) and a significant positive association with high-density lipoprotein (P<0.001, P<0.001, respectively) in multi-adjusted analyses. There was no evidence of a relationship between multimeric AN and high-sensitivity C-reactive protein. There was also little evidence of a relationship between LMW AN and CVD risk factors. There was a strong, body mass index (BMI)-independent, association between AN, CVD biomarkers and the hypertriglyceridemic waist phenotype.

CONCLUSION

Prominent, BMI-independent associations between total and HMW AN, but not LMW AN, and CVD risk factors were already evident in this young population. This research in adolescents supports the contention that AN subfractions may have different biological actions. These associations in apparently healthy adolescents suggest an important role for AN and its subfractions in the pathogenesis of metabolic syndrome traits and indicate that the potential for total or HMW AN to act as early universal biomarkers of CV risk warrants further study.

Treatment with heme arginate alleviates adipose tissue inflammation and improves insulin sensitivity and glucose metabolism in a rat model of Human primary aldosteronism

Visceral adiposity and insulin resistance are common pathophysiological denominators in patients with primary aldosteronism. Although we recently reported the antidiabetic effects of heme oxygenase (HO), no study has examined the effects of upregulating HO on visceral adiposity in uninephrectomized (UnX) deoxycorticosterone acetate (DOCA-salt) hypertensive rats, a model of human primary aldosteronism characterized by elevated endothelin (ET-1) and oxidative/inflammatory events. Here, we report the effects of the HO inducer heme arginate and the HO blocker chromium mesoporphyrin (CrMP) on visceral adipose tissue obtained from retroperitoneal fat pads of UnX DOCA-salt rats. UnX DOCA-salt rats were hypertensive but normoglycemic. Heme arginate reduced visceral adiposity and enhanced HO activity and cGMP in the adipose tissue, but suppressed ET-1, nuclear-factor κB (NF-κB), activating-protein (AP-1), c-Jun-NH2-terminal kinase (JNK), macrophage chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and 8-isoprostane. These were associated with reduced glycemia, increased insulin, and the insulin-sensitizing protein adiponectin, with corresponding reduction in insulin resistance. In contrast, the HO inhibitor, CrMP, abolished the effects of heme arginate, aggravating insulin resistance, suggesting a role for the HO system in insulin signaling. Importantly, the effects of the HO system on ET-1, NF-κB, AP-1, JNK, MCP-1, and ICAM-1 in visceral or retroperitoneal adiposity in UnX-DOCA-salt rats have not been reported. Because 8-isoprostane stimulates ET-1 to enhance oxidative insults, and increased oxidative events deplete adiponectin and insulin levels, the suppression of oxidative/inflammatory mediators such as 8-isoprostane, NF-κB, AP-1, MCP-1, ICAM-1, and JNK, an inhibitor of insulin biosynthesis, may account for the potentiation of insulin signaling/glucose metabolism by heme arginate. These data indicate that although UnX DOCA-salt rats were normoglycemic, insulin signaling was impaired, suggesting that dysfunctional insulin signaling may be a forerunner to overt diabetes in primary aldosteronism.

The association of baseline adipocytokine levels with glycemic progression in nondiabetic Korean adults in 4 years of follow-up

AIMS

Low-grade inflammation and lipotoxicity contribute to insulin resistance and islet secretory dysfunction that lead to insulin deficiency. We analyzed the associations of several adipocytokines measured at baseline with glycemic progression in non-diabetic Korean subjects after a 4-year follow-up.

METHODS

In 479 non-diabetic Korean subjects who underwent medical screening in 2003, serum tumor necrosis factor (TNF)-α, interleukin (IL)-6, retinol-binding protein (RBP)-4, monocyte chemoattractant protein (MCP)-1, visfatin and fatty acid-binding protein (FABP)-4 were measured at baseline. After 4 years, changes in glycemia were assessed.

RESULTS

Among the subjects, 79.2% maintained their baseline glycemic status, 14.6% progressed to worse glycemic status (impaired fasting glucose (IFG) to diabetes, normoglycemia to IFG or normoglycemia to diabetes) and 5.8% regressed to normoglycemia after 4 years. Baseline TNF-α and FABP4 showed the highest values in the progression group. In the logistic regression analyses with glycemic progression as the dependent variable and TNF-α and FABP4 as independent variables in separate models, TNF-α and FABP4 individually predicted glycemic progression after adjustment for confounding variables. When both adipocytokines were included in the same model, only FABP4 significantly predicted glycemic progression after 4 years.

CONCLUSIONS

TNF-α and FABP4 were significant predictors for glycemic progression in 4 years, with FABP4 being the stronger predictor.

The potential role of fatty liver in paediatric metabolic syndrome: a distinct phenotype with high metabolic risk?

BACKGROUND

The prevalence of obesity and its metabolic consequences has dramatically increased in the last two decades urging physicians to find a reliable definition for early detection, treatment and possibly prevention of metabolic syndrome (MS). MS could be diagnosed in adult patients in the presence of a large waist circumference and ≥2 of the following features: high serum triglycerides, low serum high-density lipoprotein cholesterol, high blood pressure and high fasting glucose. The definition of MS in children is more problematic, and the potential role of its single components on metabolic risk remains largely undefined. Recent evidence strongly suggests not only a relationship between non-alcoholic fatty liver disease (NAFLD) and MS in obese children, adolescents and adults, but also the key role exerted by liver fat deposition in the pathogenesis of MS.

CONCLUSION

We propose that NAFLD should be routinely checked in obese subjects because early lifestyle changes may be effective in reducing the overall risk of MS.

Macrophage migration inhibitory factor is elevated in obese adolescents

OBJECTIVES

The prevalence of obesity in childhood and adolescence is continuing rising. Macrophage migration inhibitory factor (MIF) participates in inflammatory and immune responses as a pro-inflammatory cytokine. The present study aimed to investigate MIF in overweight adolescents.

METHODS

Seventy-nine male adolescents were enrolled. Thirty-eight were overweight according to the 90th%ile of the age-specific waist circumference. Various parameters were recorded at one visit, including body mass index. MIF was determined using multiplex immune-assay technology.

RESULTS

Overweight adolescents had increased systolic blood pressure and CRP levels. Furthermore, increased circulating MIF concentrations were observed (Median: 964.6 pg/ml, Interquartile range: 590.3-2019.4 versus Median: 562.7 pg/ml, Interquartile range: 430.6-813.7, p = 0.003). Increased MIF concentrations were associated with increased markers of inflammation and obesity.

CONCLUSIONS

We demonstrated elevated MIF levels in obese adolescents. Taken together with other markers, this indicates the presence of low-grade inflammation in these young subjects, possibly representing a link between obesity and related co-morbidities.

High-molecular-weight adiponectin and anthropometric variables among elementary schoolchildren: a population-based cross-sectional study in Japan

Background

Studies about the relationship between high-molecular-weight adiponectin (HMW-adn) and anthropometric variables among population-based elementary schoolchildren have been too limited, especially in Japan, where blood collection is not usually performed in the annual health examination at elementary schools. The objective of the present study was to investigate the relationship between HMW-adn and anthropometric variables (body mass index [BMI], percent body fat [%BF], waist circumference [WC], and waist-to-height ratio [WHtR]) among population-based elementary schoolchildren in Japan.

Methods

Subjects comprised all fourth-grade schoolchildren (9 or 10 years of age) in the town of Ina, Saitama Prefecture, Japan during 2005–2008 (N = 1675). After excluding 21 subjects because of refusal to participate or incomplete data, data from a total of 1654 subjects (846 boys and 808 girls) were analyzed. The height, weight, %BF, and WC of each subject were measured, while blood samples were drawn from the subjects to measure adiponectin levels (HMW-adn and total adiponectin). Childhood obesity was determined according to the age- and sex-specific cut-off points proposed by the International Obesity Task Force. Spearman’s correlation coefficients between adiponectin levels and anthropometric variables were calculated for each sex.

Results

The anthropometric variables were negatively correlated with HMW-adn in both boys and girls. Correlation coefficients of HMW-adn with anthropometric variables in the obesity group were consistently higher than those in the non-obesity group among both boys and girls. In addition, only WHtR was significantly correlated with HMW-adn regardless of sex and physique (obesity or non-obesity); the correlation coefficient was -0.386 among boys and -0.543 among girls in the obesity group, while it was -0.124 among boys and -0.081 among girls in the non-obesity group.

Conclusions

HMW-adn was negatively correlated with anthropometric variables, while the correlation coefficients of HMW-adn with anthropometric variables in the obesity group were consistently higher than those in the non-obesity group. Moreover, only WHtR was significantly associated with HMW-adn regardless of sex and physique. The results of this study suggested that it is useful to monitor WHtR as a surrogate for HMW-adn among elementary school students, especially obese children.

Plasma total adiponectin levels in pediatrics: reference intervals calculated as a continuous variable of age

OBJECTIVE

Plasma total Adiponectin (tAN) is a novel biomarker with interesting potentialities in pediatrics. Age-related intervals are needed for the correct interpretation of results. In this study, we calculated the reference values for tAN using a large number of results derived from pediatric patients.

DESIGN AND METHODS

tAN was determined by ELISA in more than 4000 samples and the results collected in the Laboratory Information System were used for the calculation of reference intervals.

RESULTS

tAN reference values for the different age intervals were obtained and age related tAN reference intervals were calculated. Some differences were observed in males and females. In obese children, no correlation between age and tAN could be observed. On the contrary, significant relations were observed in the total group of patients and in healthy control subjects. For this reason, the parameters of the equations to calculate tAN reference values using age as a continuous variable were defined.

CONCLUSION

The use of continuous tAN reference intervals, calculated on age, should be considered a useful laboratory tool, at least in the pediatric population, for those biomarkers whose reference values have been shown to change from birth to the late adolescence.

Effects of an in-patient treatment program based on regular exercise and a balanced diet on high molecular weight adiponectin, resistin levels, and insulin resistance in adolescents with severe obesity

Adiponectin, the most abundant hormone produced by adipose tissue, circulates in 3 isoforms, including high molecular weight (HMW) adiponectin. The latter has been suggested to be a better predictor of metabolic disturbances and insulin resistance associated with obesity. This study investigated changes in total and HMW adiponectin, resistin, and homeostasis model assessment (HOMA) during a 9-month in-patient treatment program based on physical exercise and a balanced diet in 32 severely obese adolescents. Total and HMW adiponectin, resistin, and HOMA were measured at baseline (month 0) and during the program (months 3, 6, 9). In addition, a control group of 15 teenagers served as a reference for the baseline assessments. At baseline, HMW adiponectin was more markedly decreased in obese adolescents than total adiponectin, and both were lower than in controls. Conversely, resistin and HOMA were higher in obese adolescents. During the program, there was a significant change in body composition and improved insulin sensitivity among obese teenagers. In addition, HMW adiponectin and the ratio of HMW-to-total adiponectin increased throughout the study, whereas total adiponectin only increased up until the sixth month. On the contrary, resistin did not show any significant change. In obese adolescents, a long-term combination of aerobic exercise and a balanced diet, inducing change in body composition and improved insulin sensitivity, markedly increased HMW adiponectin compared with total adiponectin, without any change in resistin concentrations. Our results thus suggest that the determination of HMW adiponectin could be more useful than measurement of total adiponectin in clinical settings.

Carotid extra-medial thickness in childhood: early life effects on the arterial adventitia

OBJECTIVE

Structural modification of the arterial adventitia may be an early event in atherosclerosis. Carotid extra-medial thickness is a new measure of arterial adventitial thickness. We examined the association of cardiovascular risk factors with extra-medial thickness, in childhood.

METHODS

Carotid extra-medial thickness was assessed by high-resolution ultrasound in 389 non-diabetic children aged 8-years. A non-fasting blood sample was collected from 314 participants. Associations of gender, age, lipoproteins, blood pressure, BMI z-score, waist:height ratio and parental history of early vascular disease, with extra-medial thickness were examined.

RESULTS

Carotid extra-medial thickness was lower in girls (r=-.163, P=.001) and directly associated with systolic (r=.128, P=.009), diastolic blood pressure (r=.130, P=.009), and height (r=.170, P=.0006). These associations remained after adjustment for carotid intima-media thickness. In multivariable analysis including carotid intima-media thickness, only gender and height were significantly associated with carotid extra-medial thickness. In gender-stratified analysis, the strongest associations with extra-medial thickness were BMI z-score (r=.181, P=.01), height (r=.210, P=.003) and diastolic blood pressure (r=.167, P=.02) for boys; and systolic blood pressure (r=.153, P=.03) and parental history of premature cardiovascular disease (r=.139, P=.05) for girls. The association of BMI z-score with extra-medial thickness differed by gender (P-interaction=.04).

CONCLUSIONS

Carotid extra-medial thickness is independently associated with gender and height in childhood. Extra-medial thickness may provide important information concerning early arterial health, particularly related to the arterial adventitia.

Oxidant mechanisms in childhood obesity: the link between inflammation and oxidative stress

Evidence of obesity-induced oxidative stress in adults has emerged in the past several years, and similar evidence has been demonstrated in children more recently. The reactive species of oxygen or nitrogen can chemically alter all major classes of biomolecules by modifying their structure and function. Organisms have developed mechanisms to protect biomolecules from the deleterious effects of free radicals. These include the enzymes superoxide dismutase, catalase, and glutathione peroxidase, as well as water and lipid-soluble antioxidants, such as glutathione, ascorbate (vitamin C), α-tocopherol (vitamin E), and β-carotene. Obesity creates oxidant conditions that favor the development of comorbid diseases. Energy imbalances lead to the storage of excess energy in adipocytes, resulting in both hypertrophy and hyperplasia. These processes are associated with abnormalities of adipocyte function, particularly mitochondrial stress and disrupted endoplasmic reticulum function. In this sense, oxidative stress can also be induced by adipocyte associated inflammatory macrophages. There is a close link among obesity, a state of chronic low-level inflammation, and oxidative stress. In addition, the dysregulation of adipocytokines, which are secreted by adipose tissue and promoted by oxidative stress, act synergistically in obesity-related metabolic abnormalities. Adipocytokines link the local and systemic inflammation responses in the context of obesity. It is thought that the evaluation of oxidative status may allow for the identification of patients at an increased risk of complications. Decreasing the levels of chronic inflammation and oxidative stress in childhood may decrease cardiovascular morbidity and mortality in adulthood.