Altered plasma adipokines and markers of oxidative stress suggest increased risk of cardiovascular disease in First Nation youth with obesity or type 2 diabetes mellitus

Molecular Biomarkers for Cardiometabolic Disease: Risk Assessment in Young Individuals

Cardiometabolic diseases, including cardiovascular disease and diabetes, are major causes of morbidity and mortality worldwide. Despite progress in prevention and treatment, recent trends show a stalling in the reduction of cardiovascular disease morbidity and mortality, paralleled by increasing rates of cardiometabolic disease risk factors in young adults, underscoring the importance of risk assessments in this population. This review highlights the evidence for molecular biomarkers for early risk assessment in young individuals. We examine the utility of traditional biomarkers in young individuals and discuss novel, nontraditional biomarkers specific to pathways contributing to early cardiometabolic disease risk. Additionally, we explore emerging omic technologies and analytical approaches that could enhance risk assessment for cardiometabolic disease.

Systemic Inflammation, Oxidative Stress and Cardiovascular Health in Children and Adolescents: A Systematic Review

Recent studies indicate that cerebrovascular diseases and processes of atherosclerosis originate in the childhood era and are largely influenced by chronic inflammation. Some features of vascular dysfunction in adulthood may even be programmed prenatally via genetic influences and an unfavorable intrauterine milieu. Oxidative stress, defined by an imbalance between the production and generation of reactive oxygen species (ROS) in cells and tissues and the capability of an organism to scavenge these molecules via antioxidant mechanisms, has been linked to adverse cardiovascular health in adults, yet has not been systematically reviewed in the pediatric population. We performed a systematic search as per the PRISMA guidelines in PubMed/Medline and Cochrane Reviews and detected, in total, 1228 potentially eligible pediatric articles on systemic inflammation, oxidative stress, antioxidant use, cardiovascular disease and endothelial dysfunction. The abstracts and full-text manuscripts of these were screened for inclusion and exclusion criteria, and a total of 160 articles were included. The results indicate that systemic inflammation and oxidative stress influence cardiovascular health in many chronic pediatric conditions, including hypertension, obesity, diabetes mellitus types 1 and 2, chronic kidney disease, hyperlipidemia and obstructive sleep apnea. Exercise and diet may diminish ROS formation and enhance the total serum antioxidant capacity. Antioxidant supplementation may, in selected conditions, contribute to the diminution of the oxidative state and improve endothelial function; yet, in many areas, studies provide unsatisfactory results.

Determination of salivary concentrations of leptin and adiponectin, ability to reduce ferric ions and total antioxidant capacity of saliva in patients with severe early childhood caries

INTRODUCTION

One of the most common oral diseases affecting children is early childhood caries (ECC). The link between oxidative stress and ECC has been proven in numerous clinical studies. Technical and biological variability were so high in most of the studies that none of the markers have yet been proven suitable for routine clinical use. This study aimed to evaluate the antioxidant status and the levels of leptin and adiponectin in saliva of children with severe early childhood caries (S-ECC).

METHODS

Morning unstimulated saliva samples were collected from children (n = 40, 0-6 years old) for the evaluation of oxidative stress which were measured by total antioxidant capacity (TAC), and by the ferric reducing antioxidant power (FRAP) assays, as well as to assess the salivary levels of leptin and adiponectin. FRAP, TAC, leptin and adiponectin concentrations were evaluated in S-ECC group (n = 31) and caries free group CF (n = 9). All results were analyzed based on age and sex.

RESULTS

Overall median salivary leptin and adiponectin levels were 5.59 pg/mL and 24.86 ng/mL, respectively. Significantly lower leptin levels were observed in saliva of caries free children (4.66 pg/mL) than in the S-ECC group (6.64 pg/mL, p < 0.01). No significant difference was observed for adiponectin levels (S-ECC and CF, 25.31 and 23.2 ng/mL, respectively, p = 0.961). TAC and FRAP values of saliva had similar values in children with S-ECC and caries free children. TAC and FRAP values also remained stable with the age of the children, without significant differences with respect to sex.

CONCLUSION

The increased concentrations of leptin in saliva of children with S-ECC suggests that leptin may play a role in inflammatory and immune responses in the development of early childhood caries.

Frequency, clinical features, inflammatory cytokines and genetic background of latent autoimmune diabetes in youth in youth-onset type 2 diabetes: Results from a nationwide, multicentre, clinic-based, cross-sectional study (LADA China)

AIM

To investigate the frequency, clinical phenotype, inflammatory cytokine levels and genetics of glutamic acid decarboxylase autoantibody (GADA)-positive phenotypic youth-onset type 2 diabetes.

MATERIALS AND METHODS

This nationwide, multicentre, cross-sectional study included 5324 newly diagnosed subjects with phenotypic type 2 diabetes aged 15 years or older enrolled in the LADA China study. GADA was screened in 248 subjects with youth-onset type 2 diabetes aged 15-29 years. Subjects who presented as GADA-positive were defined as having latent autoimmune diabetes in youth (LADY). We added subjects with LADY, type 1 diabetes, type 2 diabetes and controls from the Diabetes Center of Central South University, and measured serum concentrations of interleukin-6, lipocalin 2, high-sensitivity C-reactive protein, adiponectin and human leukocyte antigen (HLA) genotyping in subjects with LADY, age- and sex-matched GADA-negative type 2 diabetes, type 1 diabetes and controls.

RESULTS

Twenty-nine of the 248 subjects (11.7%) were GADA positive. Compared with subjects with type 2 diabetes, subjects with LADY were less probable to have metabolic syndrome (27.6% vs. 59.4%; p = .001). The fasting C-peptide levels tended to be lower in subjects with LADY than in subjects with type 2 diabetes, but the difference was not statistically significant (LADY vs. type 2 diabetes: 0.21 [0.17-0.64] vs. 0.47 [0.29-0.77] nmol/L; p = .11). The cytokine levels of subjects with LADY were indistinguishable from subjects with type 1 diabetes, but subjects with LADY presented increased adiponectin levels compared with subjects with type 2 diabetes after adjusting for age, sex and body mass index (7.19 [4.05-11.66] vs. 3.42 [2.35-5.74] μg/mL; p < .05). The frequency of total susceptible HLA genotypes (DR3/3, -3/9 and -9/9) in subjects with LADY and type 1 diabetes were similarly higher than controls (LADY and type 1 diabetes vs. controls: 21.4% and 30.8% vs. 2.6%, respectively; p < .001).

CONCLUSIONS

A high GADA positivity was observed in youth-onset type 2 diabetes subjects in China. As subjects with LADY had an increased susceptible HLA genetic load and different cytokine levels compared with subjects with type 2 diabetes, differentiating LADY from phenotypic type 2 diabetes subjects is important.

Adiponectin, ALT and family history as critical markers for the development of type 2 diabetes in obese Japanese children

Aims/Introduction

An association between the pathogenesis of type 2 diabetes mellitus (T2D) and that of metabolic syndrome (MS) in obese children has been suggested. We clarified the critical markers for the development of T2D in obese Japanese children.

Methods

One hundred and seven obese children who visited our outpatient clinic were enrolled in this study. The obese subjects were divided into 3 groups: Group A, T2D (n = 19); Group B, MS but not T2D (n = 19); and Group C: non-T2D, non-MS (n = 69). In all the subjects, a biochemical examination was performed and the serum adiponectin and leptin levels were measured. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured using computed tomography images.

Results

Group A tended to have higher VAT values and VAT/SAT ratios and lower leptin and adiponectin levels, compared with Groups B and C. In Group A, the alanine aminotransferase (ALT) level was significantly higher and the aspartate aminotransferase (AST)/ALT ratio was significantly lower than in Group C. A receiver operating characteristic (ROC) analysis showed that the optimal cut-off point for adiponectin was 6.4 μg/mL (AUC = 0.859). The cut-off points for ALT, the AST/ALT ratio and VAT were 35 IU/L (AUC = 0.821), 0.85 (AUC = 0.794) and 78 cm2 (AUC = 0.713), respectively. Group A had a significantly higher frequency of a family history of T2D than Group B.

Conclusions

Our study revealed that the adiponectin level, ALT level, AST/ALT ratio, VAT value and a family history of T2D may be critical characteristic markers for T2D among obese Japanese children.

Inflammatory markers in children and adolescents with type 2 diabetes mellitus

This review examines the potential relationship between serum inflammation markers and type 2 diabetes mellitus (T2DM). Inflammation markers have been proposed as prognostic markers for the development of T2DM and its complications. Furthermore, modulation of the inflammatory process may offer future treatment strategies for T2DM. This review focuses on children and adolescents because there is usually little, if any, complications associated with other disease processes, use of medications, or active tobacco smoking. Furthermore, β-cell failure in young age cannot be solely explained by aging and exhaustion of β-cells due to insulin resistance. Pediatric studies have demonstrated that pro-inflammatory cytokines TNF-α, IL-6, IL-1β, IFNγ, PEDF, and fetuin A were increased in insulin resistance, while the anti-inflammatory cytokines adiponectin and omentin were decreased. Furthermore, TNF-α, fetuin A, FGF-21 were altered in obese children with T2DM suggesting a direct involvement in β-cell failure. Future studies focusing on children and adolescents may facilitate our understanding of T2DM as an inflammatory disease process.

Risk factors and predictive biomarkers of early cardiovascular disease in obese youth

Obesity in childhood and adolescence continues to be a major health issue due to significant health implications and to the economic burden that arise from treating this disease and its complications. Current data show that childhood obesity is no longer just a concern for developed countries, but more significantly affecting developing countries. In adult population, cardiovascular disease is the main cause of mortality and morbidity among obese patients. It is therefore believed that risk factors found in adult patients could also be observed in obese youth. These risk factors will then persist and become progressively worse if obese youth remain obese as they reach adulthood. However, risk reduction is achievable through various prevention and management strategies of obesity and obese children who become nonobese in adulthood have a significant reduction in their risk of developing cardiovascular disease. New biomarkers to improve risk assessment in obese youth are an open research field, which will eventually lead to a more targeted approach in prevention and treatment. Nevertheless, there is still a need for continuous research in understanding the roles of these biomarkers and their potential in risk prediction. Cardiovascular risk modification of childhood obesity depends on a more concerted effort among the various parties involved and particularly a global collaboration to stop the rising prevalence of the epidemic in developing countries.

Effects of a lifestyle intervention on markers of cardiometabolic risk and oxidized lipoproteins among obese adolescents with prediabetes

OBJECTIVE

Obesity and hyperglycaemia contribute to the atherosclerotic process in part through oxidative modifications to lipoprotein particles. The present study aimed to evaluate the effects of a lifestyle intervention on markers of oxidized lipoproteins in obese Latino adolescents with prediabetes.

DESIGN

Pre-post design.

SETTING

Participants were enrolled into a 12-week lifestyle intervention. Measurements pre- and post-intervention included anthropometrics and body composition, lipid panel, oxidized LDL (oxLDL), oxidized HDL (oxHDL), intake of fresh fruits and vegetables, and cardiorespiratory fitness.

PARTICIPANTS

Thirty-five obese Latino adolescents (seventeen females, eighteen males; mean age 15·5 (sd 1·0) years; mean BMI percentile 98·5 (sd 1·2)) with prediabetes.

RESULTS

Intervention participation resulted in significant reductions in weight (-1·2 %, P = 0·042), BMI and BMI percentile (-2·0 and -0·4 %, respectively, P < 0·001), body fat (-7·0 %, P = 0·025), TAG (-11·8 %, P = 0·032), total cholesterol (-5·0 %, P = 0·002), VLDL-cholesterol (-12·5 %, P = 0·029), and non-HDL-cholesterol (-6·7 %, P = 0·007). Additionally, fitness (6·4 %, P < 0·001) and intake of fruits and vegetables (42·4 %, P = 0·025) increased significantly. OxLDL decreased significantly after the intervention (51·0 (sd 14·0) v. 48·7 (sd 12·8) U/l, P = 0·022), while oxHDL trended towards a significant increase (395·2 (sd 94·6) v. 416·1 (sd 98·4) ng/ml, P = 0·056).

CONCLUSIONS

These data support the utility of lifestyle intervention to improve the atherogenic phenotype of Latino adolescents who are at high risk for developing premature CVD and type 2 diabetes.

Antioxidant properties of drugs used in Type 2 diabetes management: could they contribute to, confound or conceal effects of antioxidant therapy?

OBJECTIVES

This is a narrative review, investigating the antioxidant properties of drugs used in the management of diabetes, and discusses whether these antioxidant effects contribute to, confound, or conceal the effects of antioxidant therapy.

METHODS

A systematic search for articles reporting trials, or observational studies on the antioxidant effect of drugs used in the treatment of diabetes in humans or animals was performed using Web of Science, PubMed, and Ovid. Data were extracted, including data on a number of subjects, type of treatment (and duration) received, and primary and secondary outcomes. The primary outcomes were reporting on changes in biomarkers of antioxidants concentrations and secondary outcomes were reporting on changes in biomarkers of oxidative stress.

RESULTS

Diabetes Mellitus is a disease characterized by increased oxidative stress. It is often accompanied by a spectrum of other metabolic disturbances, including elevated plasma lipids, elevated uric acid, hypertension, endothelial dysfunction, and central obesity. This review shows evidence that some of the drugs in diabetes management have both in vivo and in vitro antioxidant properties through mechanisms such as scavenging free radicals and upregulating antioxidant gene expression.

CONCLUSION

Pharmaceutical agents used in the treatment of type 2 diabetes has been shown to exert an antioxidant effect..

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Serum oxidized low-density lipoprotein levels are related to cardiometabolic risk and decreased after a weight loss treatment in obese children and adolescents

BACKGROUND AND AIMS

The oxidation of low-density lipoprotein (LDL) cholesterol particles is an early atherogeninic event. Obese pediatric populations have higher levels of oxidized LDL (oxLDL) than normal weight children. The aim of this study was to evaluate the effect of a weight loss program on the biochemical profile and oxLDL levels in Spanish obese children and adolescents.

METHODS

Forty obese children (mean age 11 years, 51% boys) followed a 10-week weight loss program. They were dichotomized at the median of body mass index-standard deviation score (BMI-SDS) change, as high (HR) and low responders (LR) after the intervention. The intervention included a moderate energy-restricted diet, nutritional education, and family involvement. Anthropometric and biochemical measurements were performed at the beginning and during the follow up. A cardiometabolic risk score (CMS) was calculated considering metabolic risk factors.

RESULTS

Higher baseline oxLDL levels were associated with a higher CMS in obese children (P < .001). After the intervention, oxLDL significantly decreased in the HR group. Moreover, a positive correlation between changes in oxLDL and BMI-SDS (r = 0.385, P = .015) was found after the weight loss program. Interestingly, multiple-adjusted regression models showed an association between changes in total cholesterol [B: 0.127, 95% confidence interval (CI): 0.06 to 0.20] and LDL-cholesterol (B: 0.173, 95% CI: 0.08 to 0.26) with changes in oxLDL.

CONCLUSIONS

Higher baseline oxLDL levels were associated with a higher CMS in obese children. After the weight loss program, a decrease in oxLDL levels was found in HR subjects and the oxLDL levels were associated with BMI-SDS and cholesterol levels.

Murine diet-induced obesity remodels cardiac and liver mitochondrial phospholipid acyl chains with differential effects on respiratory enzyme activity

Cardiac phospholipids, notably cardiolipin, undergo acyl chain remodeling and/or loss of content in aging and cardiovascular diseases, which is postulated to mechanistically impair mitochondrial function. Less is known about how diet-induced obesity influences cardiac phospholipid acyl chain composition and thus mitochondrial responses. Here we first tested if a high fat diet remodeled murine cardiac mitochondrial phospholipid acyl chain composition and consequently disrupted membrane packing, supercomplex formation and respiratory enzyme activity. Mass spectrometry analyses revealed that mice consuming a high fat diet displayed 0.8-3.3 fold changes in cardiac acyl chain remodeling of cardiolipin, phosphatidylcholine, and phosphatidylethanolamine. Biophysical analysis of monolayers constructed from mitochondrial phospholipids of obese mice showed impairment in the packing properties of the membrane compared to lean mice. However, the high fat diet, relative to the lean controls, had no influence on cardiac mitochondrial supercomplex formation, respiratory enzyme activity, and even respiration. To determine if the effects were tissue specific, we subsequently conducted select studies with liver tissue. Compared to the control diet, the high fat diet remodeled liver mitochondrial phospholipid acyl chain composition by 0.6-5.3-fold with notable increases in n-6 and n-3 polyunsaturation. The remodeling in the liver was accompanied by diminished complex I to III respiratory enzyme activity by 3.5-fold. Finally, qRT-PCR analyses demonstrated an upregulation of liver mRNA levels of tafazzin, which contributes to cardiolipin remodeling. Altogether, these results demonstrate that diet-induced obesity remodels acyl chains in the mitochondrial phospholipidome and exerts tissue specific impairments of respiratory enzyme activity.

Arterial Stiffness, Thickness and Association to Suitable Novel Markers of Risk at the Origin of Cardiovascular Disease in Obese Children

Atherosclerosis origins early in childhood. Aim of the study was to investigate vascular signature and phenotypes of cardiovascular disease in obese children and adolescents identifying novel potential circulating markers of risk. Cross-sectional study of intima-media-thickness (IMT), pulse wave velocity (PWV), augmentation index (AIX@75), circulating markers (E-selectin, soluble-intercellular-adhesion-molecule1_ICAM1, chemerin, fatty-acid-binding protein 4, sCD36, lipopolysaccharides_LPS, oxLDL, fetuin) in 123 obese (body mass index, BMI z-score >1.645 SD) children (N=55, age ≤10 years-old) and adolescents (N=68, age >10 years-old). Adolescents had significantly higher uric acid (p=0.002), non-HDL-cholesterol (p=0.02), fasting glucose (p=0.04), systolic blood pressure (p=0.005) and PWV (p=0.02) than children. Obese adolescent patients with metabolic syndrome (MetS) abnormalities had higher PWV (p<0.05) than peers without. No differences were observed in circulating biomarkers in relationship to age and MetS status. oxLDL, sCD36 and LPS were correlated to AIX@75 and/or IMT_M in children and adolescents (p ranging from <0.05 to <0.0001). Total cholesterol, non-HDL-cholesterol, TG/HDL ratio, oxLDL, sCD36, ICAM1, LPS were significantly different across AIX@75 tertiles (p between 0.03 and 0.001). Early phenotypes of cardiovascular alterations in young severely obese patients encompass increased IMT, stiffness of intermediate size and resistance vasculature. Novel biomarkers investigated in the present study were associated to estimates of stiffness and thickness not differently from traditional risk factor such as non-HDL-cholesterol and TG/HDL ratio.

Oxidative stress and nitric oxide are increased in obese children and correlate with cardiometabolic risk and renal function

Oxidative stress and nitric oxide (NO) appear to represent important links between obesity and cardiovascular, metabolic and/or renal disease. We investigated whether oxidative stress and NO production/metabolism are increased in overweight and obese prepubertal children and correlate with cardiometabolic risk and renal function. We performed a cross-sectional evaluation of 313 children aged 8-9 years. Anthropometrics, 24-h ambulatory blood pressure, pulse wave velocity (PWV), insulin resistance (homoeostasis model assessment index (HOMA-IR)), inflammatory/metabolic biomarkers, estimated glomerular filtration rate (eGFR), plasma total antioxidant status (TAS), plasma and urinary isoprostanes (P-Isop, U-Isop), urinary hydrogen peroxide (U-H2O2), and plasma and urinary nitrates and nitrites (P-NOx, U-NOx) were compared among normal weight, overweight and obese groups, according to WHO BMI z-score reference. U-Isop were increased in the obese group, whereas U-NOx were increased in both overweight and obese children. U-Isop were positively correlated with U-H2O2, myeloperoxidase (MPO), high-sensitivity C-reactive protein, HOMA-IR and TAG. TAS correlated negatively with U-Isop and MPO and positively with PWV. HOMA-IR and U-H2O2 were associated with higher U-Isop, independently of BMI and eGFR, and total cholesterol and U-H2O2 were associated with U-NOx, independently of BMI, eGFR values and P-NOx concentration. In overweight and obese children, eGFR decreased across P-NOx tertiles (median: 139·3 (25th, 75th percentile 128·0, 146·5), 128·0 (25th, 75th percentile 121·5, 140·4), 129·5 (25th, 75th percentile 119·4, 138·3), P for linear trend=0·003). We conclude that oxidant status and NO are increased in relation to fat accumulation and, even in young children, they translate into higher values of cardiometabolic risk markers and affect renal function.

Leptin but not adiponectin is related to type 2 diabetes mellitus in obese adolescents

BACKGROUND

Adipokines have been suggested to be involved in the development of type 2 diabetes mellitus (T2DM). However, studies in humans are controversial and analyzes at the onset of disease are scarce.

METHODS

We compared adiponectin and leptin levels between 74 predominately Caucasian adolescents with T2DM and 74 body mass index (BMI)-, age-, and gender-matched controls without T2DM. Adiponectin and leptin were correlated to age, BMI, hemoglobin A1c (HbA1c), blood pressure, and lipids.

RESULTS

Adolescents with T2DM showed significant lower leptin levels as compared with controls (18 ± 12 vs. 37 ± 23 ng/mL, p < 0.001), whereas the adiponectin levels did not differ between the adolescents with and without T2DM (5.0 ± 2.5 vs. 4.9 ± 2.5 µg/mL, p = 0.833). The associations between adiponectin and high-density lipoprotein (HDL) cholesterol (r = 0.42), systolic (r = -0.15), and diastolic blood pressure (r = -0.20) were stronger as the associations of leptin to these parameters (all r < 0.07). In multiple linear regression analysis, leptin was significantly and positively associated with BMI [β-coefficient: 1.3 (95% confidence interval (95% CI): ±0.5), p < 0.001] and female sex [β-coefficient: 9.7 (95% CI: ±6.7), p = 0.005], and negatively with age [β-coefficient: -2.3 (95% CI: ±2.1), p < 0.001] and HbA1c [β-coefficient -3.1 (95% CI: ±2.1), p = 0.011]. Adiponectin was not significantly associated with BMI, HbA1c, age, or gender in multiple linear regression analysis.

CONCLUSIONS

Because adiponectin levels did not differ between obese adolescents with and without T2DM, hypoadiponectinemia as observed in obesity seems not to be involved in the genesis of T2DM. The relative hypoleptinemia in obese adolescents with T2DM as compared with obese adolescents without T2DM may contribute to the development of T2DM. Future longitudinal studies in humans are necessary to prove this hypothesis.

The relationship of oxidative stress, adiposity and metabolic risk factors in healthy Black and White American youth

What is already known about this subject African Americans are disproportionately affected by obesity and other metabolic risk factors in comparison to White Americans. Increasing prevalence of obesity has been associated with concomitant increases in childhood hypertension, dyslipidaemia and type 2 diabetes. Oxidative stress is associated with obesity in both adults and children. What this study adds Oxidative stress is positively associated with total body fat and truncal fat, but not with body mass index (BMI) or BMI z-score in healthy youth. Oxidative stress is associated with diastolic blood pressure in African American but not in White American healthy youth.

BACKGROUND

Oxidative stress is elevated in obese youth, but less is known regarding racial disparities in the relationship of oxidative stress with metabolic risk factors.

OBJECTIVES

To determine the relationship between oxidative stress and metabolic risk factors, adiposity, leptin, adiponectin and cardiovascular fitness (VO2PEAK ) in healthy African American and White American youth.

METHODS

A marker of oxidative stress (F2 -isoprostane), validated markers of metabolic risk factors, fitness and body composition were measured in African American (n = 82) and White American (n = 76) youth (8-17 years old) recruited over a range of BMI percentiles (4th to 99th).

RESULTS

F2 -isoprostane concentration was positively correlated with percentage body fat (r = 0.198) and percentage truncal fat (r = 0.173), but was not different between African American and White American males and females (P = 0.208). African American youth had significantly higher mean systolic and diastolic blood pressure (P = 0.023 and P = 0.011, respectively), body weight, BMI percentile and Tanner stage. After adjusting for gender, age, BMI and Tanner stage, African American youth varied from White Americans in the association of F2 -isoprostane with diastolic blood pressure (P = 0.047), but not with systolic blood pressure, triglycerides, VO2PEAK or homeostatic model assessment for insulin resistance (all P > 0.05).

CONCLUSIONS

Oxidative stress, as measured by urinary F2 -isoprostane concentrations, was positively associated with percent body fat and truncal fat in youth. Oxidative stress levels were similar among African American and White American youth. Among markers of the metabolic syndrome, a significant difference between African American and White American youth was demonstrated only in the association of oxidative stress with diastolic blood pressure.

Preliminary analysis of immune activation in early onset type 2 diabetes

INTRODUCTION

First Nations and other Aboriginal children are disproportionately affected by cardiometabolic diseases, including type 2 diabetes (T2D). In T2D, the disruption of insulin signalling can be driven by pro-inflammatory immunity. Pro-inflammatory responses can be fueled by toll-like receptors (TLR) on immune cells such as peripheral blood mononuclear cells (PBMC, a white blood cell population). TLR4 can bind to lipids from bacteria and food sources activating PBMC to produce cytokines tumour necrosis factor (TNF)-α and interleukin (IL)-1β. These cytokines can interfere with insulin signalling. Here, we seek to understand how TLR4 activation may be involved in early onset T2D. We hypothesized that immune cells from youth with T2D (n = 8) would be more reactive upon TLR4 stimulation relative to cells from age and body mass index (BMI)-matched controls without T2D (n = 8).

METHODS

Serum samples were assayed for adipokines (adiponectin and leptin), as well as cytokines. Freshly isolated PBMC were examined for immune reactivity upon culture with TLR4 ligands bacterial lipopolysaccharide (LPS, 2 and 0.2 ng/ml) and the fatty acid palmitate (200 µM). Culture supernatants were evaluated for the amount of TNF-α and IL-1β produced by PBMC.

RESULTS

Youth with T2D displayed lower median serum adiponectin levels compared to controls (395 vs. 904 ng/ml, p < 0.05). PBMC isolated from youth with and without T2D produced similar levels of TNF-α and IL-1β after exposure to the higher LPS concentration. However, at the low LPS dose the T2D cohort exhibited enhanced IL-1β synthesis relative to the control cohort. Additionally, exposure to palmitate resulted in greater IL-1β synthesis in PBMCs isolated from youth with T2D versus controls (p < 0.05). These differences in cytokine production corresponded to greater monocyte activation in the T2D cohort.

CONCLUSION

These preliminary results suggest that cellular immune responses are exaggerated in T2D, particularly with respect to IL-1β activity. These studies aim to improve the understanding of the biology behind early onset T2D and its vascular complications that burden First Nations people.

Pediatric non alcoholic fatty liver disease: old and new concepts on development, progression, metabolic insight and potential treatment targets

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in children. NAFLD has emerged to be extremely prevalent, and predicted by obesity and male gender. It is defined by hepatic fat infiltration >5% hepatocytes, in the absence of other causes of liver pathology. It includes a spectrum of disease ranging from intrahepatic fat accumulation (steatosis) to various degrees of necrotic inflammation and fibrosis (non-alcoholic steatohepatatis [NASH]). NAFLD is associated, in children as in adults, with severe metabolic impairments, determining an increased risk of developing the metabolic syndrome. It can evolve to cirrhosis and hepatocellular carcinoma, with the consequent need for liver transplantation. Both genetic and environmental factors seem to be involved in the development and progression of the disease, but its physiopathology is not yet entirely clear. In view of this mounting epidemic phenomenon involving the youth, the study of NAFLD should be a priority for all health care systems. This review provides an overview of current and new clinical-histological concepts of pediatric NAFLD, going through possible implications into patho-physiolocical and therapeutic perspectives.

Correlation of resistin with inflammatory and cardiometabolic markers in obese adolescents with and without metabolic syndrome

OBJECTIVE

The link between plasma resistin and obesity-related cardiometabolic disorders in children remains debatable. This study assessed the relationships of plasma resistin with cardiovascular risk factors, pro-inflammatory markers and insulin resistance index (HOMA-IR) in obese (Ob) adolescents and obese adolescents with metabolic syndrome (Ob-MS) compared to healthy controls (CO).

METHODS

114 obese adolescents (60 Ob, age 13.6 ± 0.9 years, BMI 28.0 ± 2.2 kg/m(2), and 54 Ob-MS, age 13.8 ± 1.0 years, BMI 32.5 ± 4.8 kg/m(2)) and 37 CO (age 13.7 ± 0.8 years, BMI 22.8 ± 0.8 kg/m(2)) were studied. Anthropometrics, cardiac variables as well as fasting plasma concentrations of lipids, glucose, insulin, and adipocytokines (resistin, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP)) were measured. HOMA-IR was calculated, and the presence of MS was assessed.

RESULTS

Plasma resistin was significantly higher in Ob-MS than in both Ob and CO and was correlated with anthropometric, cardiovascular, pro-inflammatory markers and several components of MS as was HOMA-IR in Ob and Ob-MS. With increasing the number of MS components, plasma resistin, pro-inflammatory markers, and HOMA-IR were also increased. Multiple regression models highlighted significant correlation between resistin and both HOMA-IR (r = 0.40, p < 0.05) and systolic blood pressure (r = 0.63, p < 0.01) in Ob-MS.

CONCLUSION

These results support the hypothesis that there is an association between circulating resistin and childhood obesity-related inflammatory and cardiometabolic events.

A matter of fat: insulin resistance and oxidative stress

BACKGROUND

Obesity is linked to insulin resistance (IR), which can lead to type 2 diabetes mellitus. Oxidative stress present in early obesity may favor the progression to comorbid conditions.

OBJECTIVE

To examine the relationship between oxidative stress biomarkers and the severity of IR in a group of obese children.

METHODS

Forty obese children with a body mass index (BMI) Z-score ≥ 2 were divided into two groups using the median obtained for the homeostasis model assessment of IR (HOMA-IR). Anthropometric parameters (including body fat composition by bioelectrical impedance) and biochemical parameters were assessed. The following biomarkers of oxidative stress were measured: malondialdehyde (MDA), carbonyl groups (CG), reduced glutathione, oxidized low-density lipoprotein, and vitamin E. Comparisons were adjusted for gender and Tanner stage.

RESULTS

Children with high values of HOMA-IR were more likely to have high body fat percentage and waist circumferences. However, the BMI Z-score did not correlate to the level of IR. Children with higher values of HOMA-IR presented increased levels of markers of oxidative stress in lipids (MDA, p = 0.005) and proteins (CG, p = 0.015). Moreover, MDA increased with increasing levels of HOMA-IR (r = 0.50, p = 0.002), suggesting that lipoperoxidation increases as IR worsens. In a multivariate regression model, only HOMA-IR was predictive of MDA values, irrespective of adiposity parameters and other metabolic risk factors (r2 = 0.22, p = 0.002).

CONCLUSIONS

Oxidative stress increases in obese children according to the severity of IR, which could be linked to the development of comorbidities.

The effects of detraining on blood adipokines and antioxidant enzyme in Korean overweight children

The present study examined the change to clarify the effects of detraining on the concentration of lipid profiles, serum adipokines and antioxidant enzyme gene expression in Korean overweight children. The subjects were normal children (n = 19) and obese children (n = 20) who were further subdivided into the overweight training (OT) group (n = 10) and the overweight detraining (OD) group (n = 10). Maximal oxygen uptake (VO(2)max); body composition; lipid profiles (TG, TC); adipokines (adiponectin and leptin); antioxidants (blood and gene expressions SOD and GPX) were measured before, 12 weeks, and 24 weeks after the exercise program. Body mass index (BMI) and %fat were significantly higher in the OD group only. However, waist hip ration (WHR) and systolic blood pressure (SBP) were significantly decreased in the OT group. TG was significantly decreased in the OT group. There was a significant difference in TG level between the two groups. Besides, adiponectin was significantly increased in both the OT group and the OD group. Furthermore, leptin was significantly decreased in the OT group. There was a significant difference in leptin level between the two groups. In training groups, the expression of SOD was significantly increased after a 12- and 24-week period (p < 0.05). However, detraining group was significantly increased after a 12-week only (p < 0.05). In addition, GPX was significantly increased after a 24-week only in the training group (p < 0.05). Thus, detraining showed that negative effected on body composition and lipid profiles and maintained of uniform period on adipokines and antioxidant enzyme the protein and expression.

Obesity modifies the relations between serum markers of dairy fats and inflammation and oxidative stress among adolescents

Pentadecanoic acid (15:0) and heptadecanoic acid (17:0), the dairy-specific saturated fatty acids have been inversely, while inflammation and oxidative stress have been positively related to the risk of cardiovascular disease (CVD). Both fatty acid metabolism and inflammation and oxidative stress may be influenced by adiposity. In the current cross-sectional analyses among adolescents (mean age 15 years), we determined whether overweight status modified the associations between dairy fatty acids (pentadecanoic acid (15:0) and heptadecanoic acid (17:0)) represented in serum phospholipids (PL) and markers of inflammation and oxidative stress. Six biomarkers for inflammation and oxidative stress were analyzed, including circulating adiponectin, C-reactive protein (CRP), cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and urinary 15-keto-dihydro-PGF2α (15-keto) and 8-iso-PGF2α (F2-iso). Generalized linear regression analyses, adjusted for age, gender, race, tanner score, total energy intake and physical activity, revealed that PL dairy fatty acids were inversely associated with CRP, F2-iso and 15-keto in overweight, but not in normal weight adolescents (all P(interaction) < 0.05). However, higher level of PL dairy fatty acids was associated with lower IL-6 among all adolescents. Further adjustment for dietary intake of calcium, vitamin D, protein, total flavonoids, and ω-3 fatty acids did not materially change the findings. Dairy-specific saturated fats, i.e., 15:0 and 17:0 fatty acids, may contribute to the potential health benefits of dairy products, especially for overweight adolescents.

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.

Circulating oxidized LDL and inflammation in extreme pediatric obesity

Oxidative stress and inflammation have not been well-characterized in extreme pediatric obesity. We compared levels of circulating oxidized low-density lipoprotein (oxLDL), C-reactive protein (CRP), and interleukin-6 (IL-6) in extremely obese (EO) children to normal weight (NW) and overweight/obese (OW/OB) children. OxLDL, CRP, IL-6, BMI, blood pressure, and fasting glucose, insulin, and lipids were obtained in 225 children and adolescents (age 13.5 ± 2.5 years; boys 55%). Participants were classified into three groups based on gender- and age-specific BMI percentile: NW (<85th, n = 127), OW/OB (85th- <1.2 times the 95th percentile, n = 64) and EO (≥1.2 times the 95th percentile or BMI ≥35 kg/m(2), n = 34). Measures were compared across groups using analysis of covariance, adjusted for gender, age, and race. Blood pressure, insulin, and lipids worsened across BMI groups (all P < 0.0001). OxLDL (NW: 40.8 ± 9.0 U/l, OW/OB: 45.7 ± 12.1 U/l, EO: 63.5 ± 13.8 U/l) and CRP (NW: 0.5 ± 1.0 mg/l, OW/OB: 1.4 ± 2.9 mg/l, EO: 5.6 ± 4.9 mg/l) increased significantly across BMI groups (all groups differed with P < 0.01). IL-6 was significantly higher in EO (2.0 ± 0.9 pg/ml) compared to OW/OB (1.3 ± 1.2 pg/ml, P < 0.001) and NW (1.1 ± 1.0 pg/ml, P < 0.0001) but was not different between NW and OW/OB. Extreme pediatric obesity, compared to milder forms of adiposity and NW, is associated with higher levels of oxidative stress and inflammation, suggesting that markers of early cardiovascular disease and type 2 diabetes mellitus are already present in this young population.

Nontraditional risk factors and biomarkers for cardiovascular disease: mechanistic, research, and clinical considerations for youth: a scientific statement from the American Heart Association

The rapid increase in the prevalence and severity of obesity in children is likely to lower the age of onset and increase the incidence of cardiovascular disease worldwide. Understanding the pathophysiology and improving the clinical management of cardiovascular disease involve a knowledge of novel risk factors and biomarkers. The clinical and mechanistic roles of these novel biological factors during childhood are currently being investigated. The goals of this scientific statement are to present the existing knowledge and theoretical framework of nontraditional risk factors for cardiovascular disease as they relate to children and adolescents, to describe the relevance and weight of available experimental and clinical evidence and the therapeutic implications pertaining to nontraditional risk factors in the pediatric population, and to stimulate further research with a goal of developing valid and reliable approaches to identify and validate novel risk factors that will aid in the clinical evaluation and perhaps prediction of cardiovascular disease in the pediatric population. Although several biomarkers are promising, substantial research is required before nontraditional risk factors can be used to identify and reduce cardiovascular disease risk in children and adolescents.

Relation of circulating oxidized LDL to obesity and insulin resistance in children

INTRODUCTION

Circulating oxidized low-density lipoprotein (LDL), a marker of oxidative stress, is associated with obesity, insulin resistance, metabolic syndrome, and cardiovascular disease in adults. However, little is known about its relation to insulin resistance and cardiovascular risk factors in children. The purpose of this study was to assess the relation of oxidative stress, measured by circulating oxidized LDL, with measures of adiposity and insulin resistance in children.

METHODS

Oxidized LDL, measures of body fatness (body mass index: BMI, percent body fat, waist circumference, percent trunk fat, abdominal visceral and subcutaneous fat), insulin resistance with euglycemic insulin clamp (Mlbm), blood pressure, and blood lipids were obtained in 78 children. Oxidized LDL was compared between normal weight children (BMI < 85th percentile) and overweight/obese children (BMI ≥ 85th percentile) and levels were evaluated for associations with body fatness and insulin resistance.

RESULTS

Oxidized LDL levels were significantly higher in overweight/obese vs. normal weight children (p < 0.0001). Oxidized LDL was significantly correlated with BMI, percent body fat, waist circumference, percent trunk fat, abdominal visceral fat, and abdominal subcutaneous fat (all p-values <0.0001). Moreover, oxidized LDL was negatively correlated with Mlbm, even after adjustment for adiposity (p < 0.01).

CONCLUSIONS

Oxidized LDL is significantly associated with adiposity and with insulin resistance, independent of body fatness, in children. Oxidative stress may be independently related to the development of insulin resistance early in life, especially in obese youth.

Insulin sensitivity, serum lipids, and systemic inflammatory markers in school-aged obese and nonobese children

The impact of obesity as a systemic low-grade inflammatory process has only partially been explored. To this effect, 704 community-based school-aged children (354 obese children and 350 age-, gender-, and ethnicity-matched controls) were recruited and underwent assessment of plasma levels of fasting insulin and glucose, lipids, and a variety of proinflammatory mediators that are associated with cardiometabolic dysfunction. Obese children were at higher risk for abnormal HOMA and cholesterol levels. Furthermore, BMI z score, HOMA, and LDL/HDL ratio strongly correlated with levels of certain inflammatory mediators. Taken together, obesity in children is not only associated with insulin resistance and hyperlipidemia, but is accompanied by increased, yet variable, expression of markers of systemic inflammation. Future community-based intervention and phenotype correlational studies on childhood obesity will require inclusion of expanded panels of inflammatory biomarkers to provide a comprehensive assessment of risk on specific obesity-related morbidities.

Relation of circulating oxidized LDL to obesity and insulin resistance in children

INTRODUCTION

Circulating oxidized low-density lipoprotein (LDL), a marker of oxidative stress, is associated with obesity, insulin resistance, metabolic syndrome, and cardiovascular disease in adults. However, little is known about its relation to insulin resistance and cardiovascular risk factors in children. The purpose of this study was to assess the relation of oxidative stress, measured by circulating oxidized LDL, with measures of adiposity and insulin resistance in children.

METHODS

Oxidized LDL, measures of body fatness (body mass index: BMI, percent body fat, waist circumference, percent trunk fat, abdominal visceral and subcutaneous fat), insulin resistance with euglycemic insulin clamp (Mlbm), blood pressure, and blood lipids were obtained in 78 children. Oxidized LDL was compared between normal weight children (BMI < 85th percentile) and overweight/obese children (BMI ≥ 85th percentile) and levels were evaluated for associations with body fatness and insulin resistance.

RESULTS

Oxidized LDL levels were significantly higher in overweight/obese vs. normal weight children (p < 0.0001). Oxidized LDL was significantly correlated with BMI, percent body fat, waist circumference, percent trunk fat, abdominal visceral fat, and abdominal subcutaneous fat (all p-values <0.0001). Moreover, oxidized LDL was negatively correlated with Mlbm, even after adjustment for adiposity (p < 0.01).

CONCLUSIONS

Oxidized LDL is significantly associated with adiposity and with insulin resistance, independent of body fatness, in children. Oxidative stress may be independently related to the development of insulin resistance early in life, especially in obese youth.

Changes in circulating satiety hormones in obese children: a randomized controlled physical activity-based intervention study

The aims of this study are to examine in children: (i) obesity-related alterations in satiety factors such as leptin, ghrelin, and obestatin; (ii) the link between satiety factors and cardiometabolic risk factors; and (iii) the impact of a physical activity-based lifestyle intervention on the levels of these satiety factors in the obese. We studied a total of 21 adolescents (BMI percentile, 99.0 +/- 0.6 for 15 obese and 56.2 +/- 1.1 for 6 lean). The obese subjects underwent a 3-month randomized controlled physical activity-based lifestyle intervention. Leptin, soluble leptin receptor (sOB-R), ghrelin, and obestatin levels were determined as the primary outcome measures. Other markers of cardiometabolic disease such as inflammation and insulin resistance were also determined. Body composition was measured by dual-energy X-ray absorptiometry. The concentrations of ghrelin, obestatin, and sOB-R were significantly lower in the obese children compared to the lean controls, whereas that of leptin was higher (all P < 0.05). Although intervention led to a net increase in obestatin (P < 0.01) and no change in ghrelin levels, the balance between ghrelin and obestatin (ratio of ghrelin to obestatin, G/O) decreased (P < 0.02). Intervention reduced leptin and increased sOB-R (P < 0.01 for both). Significant associations between satiety factors and other cardiometabolic risk factors were also observed. Taken together, alterations in the levels of satiety factors are evident early in the clinical course of obesity, but physical activity-based lifestyle intervention either prevented their continued increase or normalized their levels. These beneficial effects appear to aid in the maintenance of body weight and reduction in cardiovascular risk.

Diagnostic and Therapeutic Significance of the Oxidative Stress Parameters in Children

Pharmacotherapy of pediatric diseases represents a major challenge considering that the majority of medicines in everyday practice have not been pediatrically evaluated. The efficacy of therapy depends to a large extent on the knowledge of pathophysiological processes in the children organism at different ages. Therefore, research in that direction is of the utmost importance. An imbalance in the production of free oxygen/nitrogen species and parameters of antioxidative protection is a significant factor in many diseases (e.g. heart failure, pulmonary hypertension, asthma, neonatal sepsis, cancer etc.) in children of different age groups. Reactive oxygen/nitrogen species serve as cell signaling molecules for normal biologic processes. An increase in their generation can cause damages which can disrupt normal physiological cellular processes and eventually cause cell death. This review outlines the previous assessments of oxidative stress parameters in children of different ages for some diseases. Also, the potential diagnostic and therapeutic possibilities for the oxydative stress parameters in children have been considered.