Association between oxidative stress and masked hypertension in a multi-ethnic population of obese children and adolescents

The Response of Antioxidant Enzymes and Antiapoptotic Markers to an Oral Glucose Tolerance Test (OGTT) in Children and Adolescents with Excess Body Weight

Oxidative stress and apoptosis are involved in the pathogenesis of obesity-related diseases. This observational study investigates the antioxidant and apoptotic markers response to an oral glucose tolerance test (OGTT) in a population of overweight children and adolescents, with normal (NGT) or impaired glucose tolerance (IGT). Glucose, insulin, and C-peptide concentrations, as well as oxidative stress (SOD, GPx3) and apoptotic markers (Apo1fas, cck18), were determined at T = 0, 30, 60, 90, 120, and 180 min after glucose intake during OGTT. The lipid profile, thyroid function, insulin-like growth factor1, leptin, ghrelin, and adiponectin were also measured at baseline. The 45 participants, with a mean age of 12.15 (±2.3) years old, were divided into two subcategories: those with NGΤ (n = 31) and those with IGT (n = 14). The area under the curve (AUC) of glucose, insulin, and C-peptide was greater in children with IGT; however, only glucose differences were statistically significant. SOD and GPx3 levels were higher at all time points in the IGT children. Apo1fas and cck18 levels were higher in the NGT children at most time points, whereas Adiponectin was lower in the IGT group. Glucose increased during an OGTT accompanied by a simultaneous increase in antioxidant factors, which may reflect a compensatory mechanism against the impending increase in oxidative stress in children with IGT.

Metabolic syndrome, adiposity, diet, and emotional eating are associated with oxidative stress in adolescents

Background

Metabolic syndrome (MS), a condition related to adiposity and oxidative stress, can develop in adolescence, a critical stage in life that impacts health in adulthood. However, there is scarce scientific research about the relationship between lifestyle factors, emotion management, and oxidative stress in this phase of life.

Aim

To analyze whether nutritional parameters, lifestyle factors, emotion management, and MS in adolescents are associated with oxidative stress measured by the biomarker 8-isoprostane.

Methods

A cross-sectional study was carried out in 132 adolescents (48.5% girls, aged 12 ± 0.48 years) and data were collected on nutritional parameters (anthropometric measurements, biochemical analyzes, and blood pressure), lifestyle factors (physical activity, sleep, and diet), and emotion management (self-esteem, emotional eating, and mood). 8-isoprostane was analyzed in spot urine samples. The study population was categorized in three groups (healthy, at-risk, and with MS) using the International Diabetes Federation definition of MS in adolescents. To capture more complex interactions, a multiple linear regression was used to analyze the association between 8-isoprostane and the aforementioned variables.

Results

Urinary 8-isoprostane levels were significantly higher in the MS group compared to the healthy group (1,280 ± 543 pg./mg vs. 950 ± 416 pg./mg respectively). In addition, univariable analysis revealed positive significant associations between 8-isoprostane and body mass index, waist circumference, waist-to-height ratio, body fat percentage, blood lipid profile and glucose, emotional eating, and refined cereal intake. Conversely, a negative significant association was found between 8-isoprostane and sleep duration and fish intake. The multiple linear regression analysis revealed associations between 8-isoprostane and LDL-c (β = 0.173 value of p = 0.049), emotional eating (low β = 0.443, value of p = 0.036; high β = 0.152, value of p = 0.470), refined cereal intake (β =0.191, value of p = 0.024), and fish intake (β = -0.187, value of p = 0.050).

Conclusion

The MS group, LDL-c, emotional eating, and high refined cereals and low fish intakes were associated with higher levels of oxidative stress in an adolescent population.

The Role of Oxidative Stress Enhanced by Adiposity in Cardiometabolic Diseases

Cardiometabolic diseases (CMDs), including cardiovascular disease (CVD), metabolic syndrome (MetS), and type 2 diabetes (T2D), are associated with increased morbidity and mortality. The growing prevalence of CVD is mostly attributed to the aging population and common occurrence of risk factors, such as high systolic blood pressure, elevated plasma glucose, and increased body mass index, which led to a global epidemic of obesity, MetS, and T2D. Oxidant–antioxidant balance disorders largely contribute to the pathogenesis and outcomes of CMDs, such as systemic essential hypertension, coronary artery disease, stroke, and MetS. Enhanced and disturbed generation of reactive oxygen species in excess adipose tissue during obesity may lead to increased oxidative stress. Understanding the interplay between adiposity, oxidative stress, and cardiometabolic risks can have translational impacts, leading to the identification of novel effective strategies for reducing the CMDs burden. The present review article is based on extant results from basic and clinical studies and specifically addresses the various aspects associated with oxidant–antioxidant balance disorders in the course of CMDs in subjects with excess adipose tissue accumulation. We aim at giving a comprehensive overview of existing knowledge, knowledge gaps, and future perspectives for further basic and clinical research. We provide insights into both the mechanisms and clinical implications of effects related to the interplay between adiposity and oxidative stress for treating and preventing CMDs. Future basic research and clinical trials are needed to further examine the mechanisms of adiposity-enhanced oxidative stress in CMDs and the efficacy of antioxidant therapies for reducing risk and improving outcome of patients with CMDs.

Associations between repeated measures of urinary phthalate metabolites and biomarkers of oxidative stress in a rural agricultural cohort of children with asthma

Phthalate exposure is widespread, and studies suggest an adverse relationship with asthma morbidity, including some support for oxidative stress as an underlying pathophysiological mechanism. Urinary phthalate metabolites have been associated with biomarkers of oxidative stress, but data are few in children diagnosed with asthma. We used participant data from the Home Air in Agriculture Pediatric Intervention Trial (HAPI) to examine longitudinal relationships between phthalates and oxidative stress in a cohort of Latino children with asthma residing in an agricultural community. We used linear mixed-effects models to estimate associations between 11 urinary phthalate metabolites (and one summed measure of di-2-ethylhexyl phthalate (DEHP) metabolites, ∑DEHP) and two urinary biomarkers of oxidative stress: a biomarker of lipid peroxidation via measure of 8-isoprostane and a biomarker of DNA/RNA oxidative damage via combined measure of 8-hydroxydeoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), and 8-hydroxyguanine. Seventy-nine participants provided 281 observations. In covariate-adjusted models, we observed significant positive relationships between all phthalate metabolites and 8-isoprostane, effect sizes ranging from a 9.3 % (95 % CI: 4.2 %-14.7 %) increase in 8-isoprostane for each 100 % increase (i.e., doubling) of mono-(carboxy-isooctyl) phthalate (MCIOP), to a 21.0 % (95 % CI: 14.3 %-28.2 %) increase in 8-isoprostane for each doubling of mono-n-butyl phthalate (MNBP). For each doubling of mono-(carboxy-isononyl) phthalate (MCINP) and mono-ethyl phthalate (MEP), the DNA/RNA oxidative damage biomarker increased by 6.0 % (95 % CI: 0.2 %-12.2 %) and 6.5 % (95 % CI: 1.4 %-11.9 %), respectively. In conclusion, we provide unique data suggesting phthalate exposure is positively associated with oxidative stress in children with asthma. Our repeat measures provide novel identification of a consistent effect of phthalates on oxidative stress in children with asthma via lipid peroxidation. Confirmation in future studies of children with asthma is needed to enhance understanding of the role of phthalates in childhood asthma morbidity.

Endogenous sex hormones homeostasis disruption combined with exogenous phthalates exposure increase the risks of childhood high blood pressure: A cohort study in China

BACKGROUND

The structural similarity between sex hormones and exogenous phthalates (PAEs) enabled them as disrupters in regulating childhood blood pressure (BP). We aim to explore the association of sex hormones homeostasis and PAEs metabolites with childhood high BP (HBP).

METHODS

A cohort study was conducted with 1416 children aged 7-13 years at baseline and with 824, 819, and 801 children completing three waves' follow up. Serum testosterone (TT) and estradiol (E2) in children during three consecutive waves of surveys were measured by radioimmunoassay, and then TT/E2 ratio calculated as TT divided by E2 were used to represent sex hormones homeostasis. Seven urinary PAEs metabolites were measured in children of first wave. The BP Z-Scores and HBP across waves were obtained by sex, age, and height specific percentiles. Log-binomial regression models with adjusted risk ratios (aRR) after adjusting for confounders were utilized.

RESULTS

The prevalence of HBP at the baseline survey was 25.5%, and increased from 26.3% in the first wave of survey to 35.0% in the third wave of survey. PAEs were negatively correlated with E2, while positively correlated with TT and TT/E2 ratio. A positive association of the serum TT levels, TT/E2 ratio, and total PAEs was found with HBP prevalence (in wave 1, 2 and 3 with TT (aRR): 1.63, 1.37 and 1.45; with TT/E2: 1.63, 1.42 and 1.20; with PAEs: 1.40, 1.32 and 1.32), persistent HBP (with TT (aRR): 2.19; TT/E2: 2.16; PAEs: 2.57), occasional HBP (with TT (aRR): 1.94; TT/E2: 1.72; PAEs: 1.38), and new HBP incidence (with TT (aRR): 1.44; TT/E2: 1.57; PAEs: 1.67), but E2 had a negative association with HBP phenotypes (HBP prevalence in wave 1, 2 and 3 (aRR): 0.77, 0.93, and 1.10; persistent HBP: 0.47; occasional HBP: 0.96; new HBP incidence: 0.81). The E2 and PAEs had antagonistic effects on HBP risks in children, particularly in girls and those with high BMI group, but the TT levels, TT/E2 ratio and PAEs had synergistic effects on HBP risks in children, particularly in boys and those with high BMI group.

CONCLUSION

Exogenous PAEs exposure and endogenous sex hormones homeostasis disruption independently increase the risks of HBP. Moreover, the exogenous PAEs exposure could disrupt the endogenous sex hormones homeostasis in children, thereby combinedly increased risks of childhood HBP.

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.

The Mediation Role of Fatness in Associations between Cardiorespiratory Fitness and Blood Pressure after High-Intensity Interval Training in Adolescents

BACKGROUND

Low cardiorespiratory fitness (CRF), elevated blood pressure (BP), and high fatness are cardiovascular disease risk factors. It remains unknown how fatness affects the influence of CRF on BP. Therefore, the aim was to examine whether the associations between baseline CRF and HIIT-postintervention resting BP were mediated through fatness in adolescents.

MATERIAL AND METHODS

The sample (n = 64) comprised 28 boys 36 girls aged 16 years. The analysed factors were fitness index- reflecting CRF, body fat mass (BFM), fat mass index (FMI), and body mass index (BMI). Bootstrapped mediation procedures were performed. The mediation analysis was conducted concerning the sex moderation effect.

RESULTS

The mediation effect of sex was confirmed; therefore, mediations models were designed separately for boys and girls. The results showed a statistically significant inverse relationship between baseline CRF and post-intervention systolic blood pressure (SBP) in both sexes (boys: B = -0.603, p = 0.010; girls: B = -0.394, p = 0.037). The relations between CRF and SBP revealed the mediation effect of the BFM and the FMI only in boys.

CONCLUSIONS

Fatness mediated associations between CRF and SBP in boys. Therefore, both CRF and fatness are necessary to maintain positive results of the BP revealed in normal SBP ranges after HIIT.

Masked hypertension and correlation between body composition and nighttime blood pressure parameters in children and adolescents with obesity

INTRODUCTION

Masked hypertension is defined as having a normal blood pressure (BP) in the office but elevated BP outside the office. This study aimed to determine the prevalence of masked hypertension in participants with obesity and to examine the correlation between body composition, dietary intake and ambulatory blood pressure parameters.

MATERIALS AND METHODS

The cross-sectional study of participants with obesity was conducted in the pediatric nutrition clinic of a University Hospital in Thailand. Demographic and anthropometric data, dietary intake, body composition analysis and ambulatory blood pressure monitoring were assessed in all participants. All parameters were compared between the group with masked hypertension and the normotensive group. Correlations between the parameters were analyzed.

RESULTS

Among 49 children with obesity, 23 (47%, 95% confidence interval 34.7, 59.2%) had masked hypertension. Compared with the normotensive group, the group with masked hypertension had a greater mean BMI z-score (4.7 vs. 3.0, P = 0.003), a greater mean of body fat percentage (45 vs. 40, P = 0.012) and a greater total energy intake percentage of dietary reference intake (115 vs. 93, P = 0.034). Multivariate analysis showed that BMI z-score was significantly associated with masked hypertension. Interestingly, mean nighttime SBP positively correlated with BMI z-score and body fat percentage. Moreover, there were negative correlations between fruit intake portion per week and nighttime and 24-h SBP index. However, multivariate linear regression did not show significant correlation between these parameters.

CONCLUSIONS

Masked hypertension was frequent in participants with obesity. The greater BMI z-score and percentage of body fat mass correlated with higher nighttime SBP.

The mediating role of adiposity in the longitudinal association between cardiorespiratory fitness and blood pressure in adolescents: LabMed cohort study

BACKGROUND

The aim of this prospective cohort study was to examine whether the association between the cardiorespiratory fitness (CRF) at baseline and blood pressure (BP) at follow-up is mediated by adiposity in adolescents.

MATERIALS AND METHODS

The sample comprised 734 adolescents (349 girls) aged 12-18 years from the LabMed Physical Activity Cohort Study. The variables of interest were measured in 2011 (baseline) and in 2013 (2-year follow-up). CRF was assessed by the 20-m shuttle run test. Body mass index, waist circumference, body fat percentage, pubertal status and resting BP were assessed according to standard procedures. Boot-strapped mediation procedures were performed, and indirect effects (IE) with confidence intervals (CI) not including zero were considered statistically significant.

RESULTS

After adjusting for potential confounders, body mass index acted as a mediator of the relationship between CRF and systolic BP (IE = -0. 023; CI = -0.039; -0.009), pulse pressure (IE = -0.023; CI = -0.034; -0.012) and rate product pressure (IE = -2.839; CI = -5.329; -0.340). Similar results were obtained for waist circumference as mediator for systolic BP (IE = -0.019; CI = -0.033; -0.005), pulse pressure (IE = -0.017; CI = -0.028; -0.007) and rate product pressure (IE = -3.793; CI = -6.097; -1.689). Likewise, body fat percentage mediated the association for: systolic BP (IE = -0.029; CI = -0.048; -0.010), pulse pressure (IE = -0.027; CI = -0.041; -0.013) and rate product pressure (IE = -4.280; CI = -7.488; -1.264).

CONCLUSIONS

Adiposity mediated the association between CRF and BP in adolescents. Therefore, both optimal CRF and adiposity levels are important to maintain normal BP ranges throughout adolescence.

Can we use copeptin as a biomarker for masked hypertension or metabolic syndrome in obese children and adolescents?

OBJECTIVES

Copeptin, the C-terminal part of arginine-vasopressin, is increased in hypertensive adolescents and closely associated with metabolic syndrome (MS). We aimed to investigate whether serum copeptin can be used to differentiate masked hypertension (MHT) and MS, and the role of sodium intake, natriuretic peptide response and renin-angiotensin-aldosterone system in MHT and MS in obese youth.

METHODS

Obese children aged 10-18 years with normal office blood pressure measurements were included. Patients with MHT and normotension and those with MS and non-MS were evaluated separately. Biochemical parameters, copeptin, brain natriuretic peptide (BNP), aldosterone, renin, urine sodium, and protein were evaluated. Echocardiography, fundoscopic examination, and ambulatory blood pressure monitoring were performed.

RESULTS

There were 80 (M/F=39/41) obese patients with a mean age of 13.78 ± 1.93 years. The cases with MHT, MS, and concomitant MHT and MS were 53,24, and 13%, respectively. Copeptin levels were similar among patients with and without MHT or MS (p>0.05). However, multivariate analysis revealed that copeptin significantly increased the probability of MHT (OR 1.01, 95% CI=1.001-1.018, p=0.033). Copeptin was positively correlated with daytime systolic and diastolic load, aldosterone, BNP, and urine microalbumin/creatinine levels (p<0.05). Linear regression analyses revealed that copeptin was significantly correlated with BNP regardless of having MHT or MS in obese youth. In the MHT group, 24-h sodium excretion was not significantly correlated with BNP.

CONCLUSION

Copeptin may be a beneficial biomarker to discriminate MHT, but not MS in obese children and adolescents. An insufficient BNP response to sodium intake might be one of the underlying causes of MHT in obese cases.

Diagnosis and Management of Endocrine Hypertension in Children and Adolescents

Hypertension in childhood and adolescence has increased in prevalence. Interest in the disease was raised after the 2017 clinical practice guidelines of the American Academy of Paediatrics on the definition and classification of paediatric hypertension. Among the secondary causes of paediatric hypertension, endocrine causes are relatively rare but important due to their unique treatment options. Excess of catecholamine, glucocorticoids and mineralocorticoids, congenital adrenal hyperplasia, hyperaldosteronism, hyperthyroidism and other rare syndromes with specific genetic defects are endocrine disorders leading to paediatric and adolescent hypertension. Adipose tissue is currently considered the major endocrine gland. Obesity-related hypertension constitutes a distinct clinical entity leading to an endocrine disorder. The dramatic increase in the rates of obesity during childhood has resulted in a rise in obesity-related hypertension among children, leading to increased cardiovascular risk and associated increased morbidity and mortality. This review presents an overview of pathophysiology and diagnosis of hypertension resulting from hormonal excess, as well as obesity-related hypertension during childhood and adolescence, with a special focus on management.

Metformin Alleviates Obesity and Systemic Oxidative Stress in Obese Young Swine

The present study assessed the relationship between obesity induced by lifestyle and systemic oxidative stress and possible modulations by oral metformin treatments in young individuals, by using a translational swine model of obesity and associated cardiometabolic disorders (Iberian pig). The results indicate the existence of an age-related increase in both adiposity and systemic oxidative stress (using hydrogen peroxide as a marker), which is higher in individuals with obesogenic lifestyle and increased weight and obesity. Such effect was not found in individuals treated with metformin. The translation of these results suggests that childhood obesity increases production of reactive oxygen species (ROS), and therefore systemic oxidative stress. Treatment with metformin would improve such oxidative status.

Influence of pubertal development on urinary oxidative stress biomarkers in adolescent girls in the New York LEGACY cohort

Puberty is a time of intense growth and differentiation of breast tissue and a window of susceptibility (WOS) for breast cancer. Although oxidative stress markers have been associated with breast cancer risk, it is unclear whether oxidative stress levels are different during the pubertal WOS, and if so, whether these differences are related to breast cancer susceptibility. We measured urinary biomarkers of whole body oxidative stress (urinary F2-Isoprostanes and 8-oxodeoxyguanosine (8-oxodG)) in 158 girls (ages 6-13 years), 71 with and 87 without a breast cancer family history (BCFH) from a cohort of adolescent girls from the New York site of the LEGACY cohort (Lessons in Epidemiology and Genetics in Adults Cancer from Youth). We compared levels of urinary oxidative stress biomarkers (F2-Isoprostanes and 8-oxodG) across the pubertal window, defined by Tanner Stage (TS) of breast development, both cross-sectionally and longitudinally within girls over an 18-month follow up period. Urinary oxidative stress biomarkers were unrelated to pubertal stages in cross-sectional analyses after considering adjustments for body mass index (BMI) and BCFH. In our longitudinal analysis, we found that urinary 8-oxodG levels, but not F2-Isoprostane levels, increased with age in BCFH + girls (β = 6.12, 95% CI = 0.08-12.16) compared to BCFH-girls. Higher BMI was associated with higher level of F2-Isoprostane in both cross-sectional (β = 0.02, 95% CI = 0.0004-0.05) and longitudinal analysis (β = 0.02, 95% CI = 0.0002-0.05). These findings support that higher BMI increases oxidative stress biomarkers over the pubertal window and that there are changes in 8-oxodG oxidative stress biomarkers in girls with a BCFH compared to girls without a BCFH.

Heart rate as cardiovascular risk factor

Heart rate is a parameter that is widely used by the general population as a marker of health. The availability of wearable electronic heart rate monitoring devices and use of specific apps are widely used both at rest and during daily life activities. Resting heart rate values gained more relevance with the evidence of association between elevated heart rate values at rest and diseases and adverse events. Also longitudinal studies demonstrated a clear association between increase in heart rate over time and cardiovascular and all-cause mortality. The increased knowledge of physiological mechanisms of heart rate control and the pathophysiological mechanisms responsible for its dysfunction allows identification of the cutoff value of normalcy. This information can be used to select non-pharmacological and pharmacological interventions to reduce the cardiovascular risk both in the general population and in patients with pathophysiological conditions. This review provides an overview of the current knowledge of resting heart rate as cardiovascular risk factor.

Systemic anti-oxidant capacity is inversely correlated with systolic blood pressure and pulse pressure in children with obesity

BACKGROUND AND AIMS

Oxidative stress leading to endothelial dysfunction is a candidate driver of obesity-related hypertension. We aimed to assess whether the total anti-oxidant capacity (TAC) was associated with blood pressure in children/adolescents with obesity.

METHODS AND RESULTS

One hundred and fifty-two children/adolescents with obesity (79 boys; age 11.9+/-2.5 years) underwent blood drawing for the assessment of TAC, lipids and HOMA-IR. Blood pressure was measured and classified according to the latest American Academy of Pediatrics Guidelines. Serum TAC was measured by a commercial kit (Sigma-Aldrich). The average TAC was 1.11+/-0.4 mMol/Trolox equivalents. Systolic blood pressure was predicted by TAC (B = -5.8, p = 0.003), z-BMI (B = 2.39, p = 0.008), height [cm] (B = 0.38, p < 0.001) and diastolic blood pressure (B = 0.56, p < 0.001). Diastolic blood pressure was predicted by age [years] (B = 0.58, p = 0.001), log-HOMA-IR (B = 3.0, p = 0.002), and systolic blood pressure (B = 0.26, p < 0.001), but not by TAC. The pulse pressure was predicted only by TAC (B = - 6.6, p = 0.002), and height [cm] (B = 0.42, p < 0.001). Overall "elevated blood pressure + hypertension" or hypertension alone were not associated with TAC. However, systolic "elevated blood pressure + hypertension" was associated with TAC (OR = 0.4 [0.1-0.9], p = 0.037), and z-BMI (OR = 2.1 [1.3-3.6], p = 0.004).

CONCLUSION

The systemic anti-oxidant capacity is inversely associated with systolic blood pressure and pulse pressure in children and adolescents with obesity.

Phthalate-associated hypertension in premature infants: a prospective mechanistic cohort study

BACKGROUND

Phthalates are associated with increased blood pressure in children. Large exposures to di-(2-ethylhexyl) phthalate (DEHP) among premature infants have been a cause for concern.

METHODS

We conducted a prospective observational cohort study to determine if DEHP exposures are related to systolic blood pressure (SBP) in premature infants, and if this exposure is associated with activation of the mineralocorticoid receptor (MR). Infants were monitored longitudinally for 8 months from birth. Those who developed idiopathic hypertension were compared with normotensive infants for DEHP exposures. Appearance of urinary metabolites after exposure was documented. Linear regression evaluated the relationship between DEHP exposures and SBP index and whether urinary cortisol/cortisone ratio (a surrogate marker for 11β-HSD2 activity) mediated those relationships. Urinary exosomes were quantified for sodium transporter/channel expression and interrogated against SBP index.

RESULTS

Eighteen patients met the study criteria, nine developed transient idiopathic hypertension at a postmenstrual age of 40.6 ± 3.4 weeks. The presence of urinary DEHP metabolites was associated with prior IV and respiratory tubing DEHP exposures (p < 0.05). Both IV and respiratory DEHP exposures were greater in hypertensive infants (p < 0.05). SBP index was related to DEHP exposure from IV fluid (p = 0.018), but not respiratory DEHP. Urinary cortisol/cortisone ratio was related to IV DEHP and SBP index (p < 0.05). Sodium transporter/channel expression was also related to SBP index (p < 0.05).

CONCLUSIONS

Increased blood pressure and hypertension in premature infants are associated with postnatal DEHP exposure. The mechanism of action appears to be activation of the MR through inhibition of 11β-HSD2.

The influence of oxidative stress on cardiac remodeling in obese adolescents

Oxidative stress seems to be an important link between obesity and cardiovascular disease. The aim of our study was to assess oxidative stress in obese patients stratified according to ambulatory blood pressure status and to determine independent predictors of abnormal left ventricular geometry.A cross-sectional study was conducted. A total of 113 obese participants referred for 24-h ambulatory blood pressure monitoring (ABPM) aged 9-19 years, and 29 healthy controls were enrolled. In addition to anthropometric and biochemical measurements, such as fasting serum levels of glucose, insulin, lipid profile, and oxidative biomarkers, ABPM and echocardiography were performed.According to ABPM results, obese subjects were split in two groups: 57 hypertensive and 56 normotensive. Both hypertensive and normotensive obese participants had higher levels of oxidative stress parameters (pro-oxidative/antioxidative balance and total oxidant status) compared with control group. Levels of superoxide anion (O₂^-) and sulfhydryl groups were higher in obese hypertensive participants as compared to obese normotensive and control groups. Abnormal left ventricular geometry among obese participants was independently associated with O₂^- (p = .006) and body mass index z score (p = .020), with no significant impact of gender, while age and systolic blood pressure exhibited interaction term for the outcome.The independent effect of oxidative mechanisms on left ventricular geometry appears to start in childhood. Oxidative stress occurs in obese adolescents prior to the development of sustained hypertension.

Catalase-Containing Silica Particles as Ultrasound-Based Hydrogen Peroxide Sensors to Determine Infected From Noninfected Fluid Collections in Humans

OBJECTIVE. Hydrogen peroxide (H₂O₂) plays a key role in neutrophil oxidative defense against infection. Catalase-containing silica nanoshells are nanoparticles that generate O₂ microbubbles imaged with ultrasound in the presence of elevated H₂O₂. We aimed to determine whether ultrasound-detectable O₂ microbubbles produced by catalase-containing silica nanoshells can determine whether fluid collections drained from patients are infected. SUBJECTS AND METHODS. During this HIPAA-compliant, institutional review board-approved study, 52 human fluid samples were collected from clinically required image-guided percutaneous drainage procedures. Catalase-containing silica nanoshells were added to the fluid samples during imaging in real time using a Sequoia-512 15L8-S linear transducer (Siemens Healthcare). Production of detectable microbubbles was graded subjectively as negative (noninfected) or positive (infected) with low, moderate, or high confidence by a single observer blinded to all clinical data. The truth standard was microbiology laboratory culture results. Performance characteristics including ROC curves were calculated. RESULTS. Microbubble detection to distinguish infected from noninfected fluids was 84% sensitive and 72% specific and offered negative and positive predictive values of 89% and 64%, respectively. The AUC was 0.79. Six of nine false-positive samples were peritoneal fluid collections that were all collected from patients with decompensated cirrhosis. CONCLUSION. The presence of elevated H₂O₂ indicated by microbubble formation in the presence of catalase-containing silica nanoshells is sensitive in distinguishing infected from noninfected fluids and offers a relatively high negative predictive value. False-positive cases may result from noninfectious oxidative stress. Catalase-containing silica nanoshells may constitute a novel point-of-care test performed at time of percutaneous drainage, potentially obviating placement of drains into otherwise sterile collections and minimizing risk of secondary infection or other complication.

Association of urinary concentrations of phthalate metabolites with cardiometabolic risk factors and obesity in children and adolescents

This study aimed to investigate the association of urinary concentration of phthalate metabolites with obesity and cardiometabolic risk factors in a pediatric population. This study was conducted in 2016 on 242 children and adolescents, aged 6-18 years, living in Isfahan, Iran. Urinary concentration of mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), Mono-2-ethylhexyl phthalate (MEHP), Mono-methyl phthalate (MMP), Mono (2-ethyl-5-exohexyl) phthalate (MEOHP), and mono (2-ethyl-5hydroxyhexyl) phthalate (MEHHP) metabolites were determined. The association of these metabolites with obesity and cardiometabolic risk factors was examined using student t-test, linear and logistics regression tests. Of the 242 participants studied, 140 (57.9%) were girls and 102 (42.1%) were boys. The mean (SD) age of the population was 11.34 (2.55) years and no significant difference existed in terms of age (p-value = 0.374). MBzP, MBP, MMP were observed in urine samples of all subjects, and MEHP, MEOHP, and MEHHP were observed in 99.6, 95.87, and 96.28% of the subjects, respectively. Of the total participants, 15.2% (n = 37) were obese and 37.7% (n = 92) were overweight. According to the logistic regression analysis, except MEOHP, all other pollutants were significantly associated with obesity (OR _adjusted >1, p-value ≤ 0.002). A significant association existed between MBP and elevated blood pressure [OR _crude in tertile3 = 4.87 (CI: 1.02-23.32), p-value = 0.024]. MBzP and MEHP were significantly associated with obesity, elevated levels of triglyceride and blood pressure. Increase in MBzP metabolite in the 3rd tertile resulted to about 2.5-fold increase in triglyceride levels than the first tertile [OR _{multivariate adjusted} = 2.7 (CI: 1.23-6.22)]. The findings of this study clearly showed the association between phthalate metabolites with obesity, cardiometabolic risk factors in children and adolescents, however further longitudinal studies are necessary to evaluate the clinical effects of this finding.

Oxidative stress in obese children and adolescents with and without type 2 diabetes mellitus is not associated with obstructive sleep apnea

PURPOSE

Obesity, obstructive sleep apnea (OSA), and type 2 diabetes mellitus (T2DM) are associated with chronic low-grade inflammation and oxidative stress. In adults, increased lipid peroxidation, a marker of oxidative stress, was found in both metabolic syndrome and OSA. Studies on oxidative stress in children with T2DM and OSA are scarce.

METHODS

Plasma oxidized low-density lipoprotein (Ox-LDL) levels were evaluated in obese children and adolescents with/without T2DM, and the contribution of OSA to oxidative stress was investigated.

RESULTS

Ten patients with T2DM, 8 with impaired glucose tolerance (IGT), and 20 body mass index-standard deviation score (BMI-SDS)-matched non-diabetic children (controls) were studied. They all underwent overnight polysomnography. Fasting plasma concentrations of Ox-LDL were measured and compared to the glycemic status and to the presence of OSA. Fourteen patients (36%) were diagnosed with OSA and 21 (55%) with hypertension. There were no significant group differences in plasma Ox-LDL levels or between patients with/without OSA. Plasma Ox-LDL levels were significantly higher among patients with hypertension compared to controls (P = 0.01), while they correlated with homeostasis model assessment (P = 0.02), BMI-SDS (P = 0.049), and systolic blood pressure (P = 0.002).

CONCLUSIONS

The findings of this pilot study suggest that increased lipid peroxidation is associated with insulin resistance and hypertension in obese children and adolescents, while OSA has most likely minor influence.

Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents

These pediatric hypertension guidelines are an update to the 2004 "Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents." Significant changes in these guidelines include (1) the replacement of the term "prehypertension" with the term "elevated blood pressure," (2) new normative pediatric blood pressure (BP) tables based on normal-weight children, (3) a simplified screening table for identifying BPs needing further evaluation, (4) a simplified BP classification in adolescents ≥13 years of age that aligns with the forthcoming American Heart Association and American College of Cardiology adult BP guidelines, (5) a more limited recommendation to perform screening BP measurements only at preventive care visits, (6) streamlined recommendations on the initial evaluation and management of abnormal BPs, (7) an expanded role for ambulatory BP monitoring in the diagnosis and management of pediatric hypertension, and (8) revised recommendations on when to perform echocardiography in the evaluation of newly diagnosed hypertensive pediatric patients (generally only before medication initiation), along with a revised definition of left ventricular hypertrophy. These guidelines include 30 Key Action Statements and 27 additional recommendations derived from a comprehensive review of almost 15 000 published articles between January 2004 and July 2016. Each Key Action Statement includes level of evidence, benefit-harm relationship, and strength of recommendation. This clinical practice guideline, endorsed by the American Heart Association, is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient diagnoses and outcomes, support implementation, and provide direction for future research.

Vitamin D supplementation, the metabolic syndrome and oxidative stress in obese children

BACKGROUND

Previous studies suggest that vitamin D may play a role in cardiovascular and metabolic health. Oxidative stress has also been implicated in the development of cardiovascular disease. Evidence suggests that vitamin D deficiency may contribute to the occurrence of oxidative stress. This study aimed to determine whether treatment and correction of vitamin D deficiency in obese children led to changes in their metabolic profile, independent of changes in adiposity. In addition, we aimed to determine whether vitamin D deficiency and oxidative stress are causally related in obese children.

METHODS

In the retrospective arm, chart review identified 32 obese children who experienced normalization of vitamin D deficiency or insufficiency with vitamin D supplementation. We then correlated laboratory and anthropometric data with vitamin D levels. In the prospective arm of the study, urinary 8-isoprostane and hydrogen peroxide were measured before and after correction of vitamin D deficiency/insufficiency and correlated to vitamin D levels in seven patients.

RESULTS

In our predominantly Hispanic population of obese children in an urban setting, we demonstrated a cause-effect relationship between vitamin D deficiency and oxidative stress. In contrast, we found no association between vitamin D status, adiposity, and markers of insulin sensitivity, nor any effect of vitamin D treatment on the same parameters.

CONCLUSIONS

These discordant findings suggest a differential effect of vitamin D on cardiovascular risk factors such as oxidative stress and insulin resistance. To confirm these findings, further prospective studies with larger sample size and longer follow-up are warranted.

Classifying oxidative stress by F2-isoprostane levels across human diseases: A meta-analysis

The notion that oxidative stress plays a role in virtually every human disease and environmental exposure has become ingrained in everyday knowledge. However, mounting evidence regarding the lack of specificity of biomarkers traditionally used as indicators of oxidative stress in human disease and exposures now necessitates re-evaluation. To prioritize these re-evaluations, published literature was comprehensively analyzed in a meta-analysis to quantitatively classify the levels of systemic oxidative damage across human disease and in response to environmental exposures.

In this meta-analysis, the F₂-isoprostane, 8-iso-PGF_2α, was specifically chosen as the representative marker of oxidative damage. To combine published values across measurement methods and specimens, the standardized mean differences (Hedges’ g) in 8-iso-PGF_2α levels between affected and control populations were calculated.

The meta-analysis resulted in a classification of oxidative damage levels as measured by 8-iso-PGF_2α across 50 human health outcomes and exposures from 242 distinct publications. Relatively small increases in 8-iso-PGF_2α levels (g<0.8) were found in the following conditions: hypertension (g=0.4), metabolic syndrome (g=0.5), asthma (g=0.4), and tobacco smoking (g=0.7). In contrast, large increases in 8-iso-PGF_2α levels were observed in pathologies of the kidney, e.g., chronic renal insufficiency (g=1.9), obstructive sleep apnoea (g=1.1), and pre-eclampsia (g=1.1), as well as respiratory tract disorders, e.g., cystic fibrosis (g=2.3).

In conclusion, we have established a quantitative classification for the level of 8-iso-PGF_2α generation in different human pathologies and exposures based on a comprehensive meta-analysis of published data. This analysis provides knowledge on the true involvement of oxidative damage across human health outcomes as well as utilizes past research to prioritize those conditions requiring further scrutiny on the mechanisms of biomarker generation.

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Oxidative damage is highly variable in human conditions as measured by F₂-isoprostanes.

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Respiratory tract and urogenital diseases have the highest F₂-isoprostanes.

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Cancer and cardiovascular diseases have surprisingly low F₂-isoprostanes.

One-year follow-up of clinical, metabolic and oxidative stress profile of morbid obese patients after laparoscopic sleeve gastrectomy. 8-oxo-dG as a clinical marker

Obesity has grown worldwide over the last few decades. In its different degrees, obesity is accompanied by many clinical and biochemical alterations reflecting the pathological condition of various body tissues. Among the mechanisms underlying the pathogenesis of obesity and associated complications, oxidative stress (OS) may be playing an important role. In the present study, we have characterized at systemic level the degree of OS status in a group of morbid obese patients (BMI>40kg/m²) at basal sate and its modulation during one year after bariatric surgery using the laparoscopic sleeve gastrectomy (LSG) technique. As compared with normal weight subjects matched in age, peripheral blood mononuclear cells (PBMc) of obese patients present a significant reduction of the antioxidant enzyme activities superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) as well as a significant increase of the oxidized/reduced glutathione ratio (GSSG/GSH) in these cells. Lipid peroxidation is significantly increased in the patient group as shown by the increased levels of malondialdehyde (MDA) in PBMc and the amount of F2-Isoprostanes (F2-IsoPs) released in urine. In addition, the DNA damage product 8-oxo-7,8-2'-deoxyguanosine (8-oxo-dG) was also observed to be increased in serum and urine of morbid obese patients as compared with the control group. After LSG, an improvement of their ponderal and metabolic profile was accompanied by a progressive recovery of antioxidant enzyme activities and the decline of oxidative byproducts both in PBMc and biological fluids. The observed changes of urinary 8-oxo-dG levels correlate positively with its serum concentration, the lipid peroxidation products MDA and F2-IsoPs, triglycerides, glucose, insulin, HOMA index and body weight and negatively with the percentage of weight and BMI loss and antioxidant activities. We conclude that the analysis of urinary 8-oxo-dG could be validated as a useful marker for the monitoring of ponderal and metabolic status of morbid obese patients.

Associations among oxidative stress, Lp-PLA2 activity and arterial stiffness according to blood pressure status at a 3.5-year follow-up in subjects with prehypertension

BACKGROUND AND AIMS

We aimed to determine changes in oxidative stress, lipoprotein-associated phospholipase A₂ (Lp-PLA₂) activity and arterial stiffness in subjects with persistent prehypertensive symptoms during a 3.5-year follow-up period.

METHODS

We divided 254 subjects with prehypertension according to their blood pressure (BP) status at 3.5 years of follow-up into three groups: reversed normotensive, persistent prehypertensive and developed hypertensive group. BP, serum lipid profile, oxidized LDL (ox-LDL), Lp-PLA₂ activity and brachial-ankle pulse wave velocity (ba-PWV) were measured at baseline and the 3.5-year follow-up.

RESULTS

The reversed normotensive group showed a significant reduction in average BP (14.7/10.1 mmHg), whereas the developed hypertensive group showed a significant increase in average BP (15.2/11.5 mmHg). The persistent prehypertensive group showed increases in serum lipid profiles, circulating levels of Lp-PLA₂ activity, ox-LDL and arterial stiffness as measured by ba-PWV at 3.5 years. The persistent prehypertensive and developed hypertensive groups showed greater increases in ox-LDL than the reversed normotensive group. The developed hypertensive group showed greater increases in Lp-PLA₂, 8-epi-PGF_2α, and ba-PWV than those observed in the reversed normotensive and persistent prehypertensive groups. In all subjects, changes (Δ) in systolic blood pressure (SBP) positively correlated with Δ Lp-PLA₂, Δ ox-LDL, Δ urinary 8-epi-PGF_2α and Δ ba-PWV.

CONCLUSIONS

This study indicates that in persistent prehypertension, increased ox-LDL hydrolysis by Lp-PLA₂ enhances arterial stiffness without an age-related increase in BP.

Prenatal phthalate exposure and 8-isoprostane among Mexican-American children with high prevalence of obesity

Oxidative stress has been linked to many obesity-related conditions among children including cardiovascular disease, diabetes mellitus and hypertension. Exposure to environmental chemicals such as phthalates, ubiquitously found in humans, may also generate reactive oxygen species and subsequent oxidative stress. We examined longitudinal changes of 8-isoprostane urinary concentrations, a validated biomarker of oxidative stress, and associations with maternal prenatal urinary concentrations of phthalate metabolites for 258 children at 5, 9 and 14 years of age participating in a birth cohort residing in an agricultural area in California. Phthalates are endocrine disruptors, and in utero exposure has been also linked to altered lipid metabolism, as well as adverse birth and neurodevelopmental outcomes. We found that median creatinine-corrected 8-isoprostane concentrations remained constant across all age groups and did not differ by sex. Total cholesterol, systolic and diastolic blood pressure were positively associated with 8-isoprostane in 14-year-old children. No associations were observed between 8-isoprostane and body mass index (BMI), BMI Z-score or waist circumference at any age. Concentrations of three metabolites of high molecular weight phthalates measured at 13 weeks of gestation (monobenzyl, monocarboxyoctyl and monocarboxynonyl phthalates) were negatively associated with 8-isoprostane concentrations among 9-year olds. However, at 14 years of age, isoprostane concentrations were positively associated with two other metabolites (mono(2-ethylhexyl) and mono(2-ethyl-5-carboxypentyl) phthalates) measured in early pregnancy. Longitudinal data on 8-isoprostane in this pediatric population with a high prevalence of obesity provides new insight on certain potential cardiometabolic risks of prenatal exposure to phthalates.

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.

Urinary Phthalate Metabolites and Biomarkers of Oxidative Stress in a Mexican-American Cohort: Variability in Early and Late Pregnancy

People are exposed to phthalates through their wide use as plasticizers and in personal care products. Many phthalates are endocrine disruptors and have been associated with adverse health outcomes. However, knowledge gaps exist in understanding the molecular mechanisms associated with the effects of exposure in early and late pregnancy. In this study, we examined the relationship of eleven urinary phthalate metabolites with isoprostane, an established marker of oxidative stress, among pregnant Mexican-American women from an agricultural cohort. Isoprostane levels were on average 20% higher at 26 weeks than at 13 weeks of pregnancy. Urinary phthalate metabolite concentrations suggested relatively consistent phthalate exposures over pregnancy. The relationship between phthalate metabolite concentrations and isoprostane levels was significant for the sum of di-2-ethylhexyl phthalate and the sum of high molecular weight metabolites with the exception of monobenzyl phthalate, which was not associated with oxidative stress at either time point. In contrast, low molecular weight metabolite concentrations were not associated with isoprostane at 13 weeks, but this relationship became stronger later in pregnancy (p-value = 0.009 for the sum of low molecular weight metabolites). Our findings suggest that prenatal exposure to phthalates may influence oxidative stress, which is consistent with their relationship with obesity and other adverse health outcomes.

Primary hypertension is a disease of premature vascular aging associated with neuro-immuno-metabolic abnormalities

There is an increasing amount of data indicating that primary hypertension (PH) is not only a hemodynamic phenomenon but also a complex syndrome involving abnormal fat tissue distribution, over-activity of the sympathetic nervous system (SNS), metabolic abnormalities, and activation of the immune system. In children, PH usually presents with a typical phenotype of disturbed body composition, accelerated biological maturity, and subtle immunological and metabolic abnormalities. This stage of the disease is potentially reversible. However, long-lasting over-activity of the SNS and immuno-metabolic alterations usually lead to an irreversible stage of cardiovascular disease. We describe an intermediate phenotype of children with PH, showing that PH is associated with accelerated development, i.e., early premature aging of the immune, metabolic, and vascular systems. The associations and determinants of hypertensive organ damage, the principles of treatment, and the possibility of rejuvenation of the cardiovascular system are discussed.

Pathophysiology of hypertension in obese children: a systematic review

Hypertension is increasingly common in overweight and obese children. The mechanisms behind the development of hypertension in obesity are complex, and evidence is limited. In order to effectively treat obese children for hypertension, it is important to have a deeper understanding of the pathophysiology of hypertension in obese children. The present review summarizes the main factors associated with hypertension in obese children and discusses their potential role in its pathophysiology. Systematic searches were conducted in PubMed and EMBASE for articles published up to October 2014. In total, 60 relevant studies were included. The methodological quality of the included studies ranged from weak to strong. Several factors important in the development of hypertension in obese children have been suggested, including endocrine determinants, such as corticosteroids and adipokines, sympathetic nervous system activity, disturbed sodium homeostasis, as well as oxidative stress, inflammation and endothelial dysfunction. Understanding the pathophysiology of hypertension in overweight and obese children is important and could have implications for its screening and treatment. Based on solely cross-sectional observational studies, it is impossible to infer causality. Longitudinal studies of high methodological quality are needed to gain more insight into the complex mechanisms behind the development of hypertension in obese children.

Association of exposure to di-2-ethylhexylphthalate replacements with increased blood pressure in children and adolescents

Phthalates are environmental chemicals widely used in consumer and personal care products. In this study, we examined associations of urinary phthalates with blood pressure, triglycerides, and lipoproteins in children and adolescents, performing a cross-sectional analysis of a subsample of US children 6 to 19 years of age who participated in the National Health and Nutrition Examination Survey between the years 2009 and 2012. We quantified exposure to common environmental phthalates, with a focus on the dietary contaminant di-2-ethylhexylphthalate and 2 increasingly used replacements, di-isononyl phthalate and di-isodecyl phthalate, based on micromolar concentration of urinary metabolites. We assessed descriptive, univariate, and multivariable associations with blood pressure and lipids. Controlling for an array of sociodemographic and behavioral factors, as well as diet and body mass, metabolites of di-2-ethylhexylphthalate, di-isononyl phthalate, and di-isodecyl phthalate were associated with higher age-, sex- and height-standardized blood pressure. For each log unit increase in di-isodecyl phthalate metabolites, a 0.105 standard deviation unit increase in systolic blood pressure z score was identified (P=0.004); for di-isononyl phthalate metabolites, a 0.113 standard deviation unit increment was identified (P=0.008). For di-2-ethylhexylphthalate metabolites, a 0.103 standard deviation unit increment (P=0.013) was detected. Metabolites of low molecular weight phthalates commonly found in cosmetics and personal care products showed an association with blood pressure (≥90th percentile) in univariate analysis, but this was no longer significant in our full multivariable model, suggesting specificity. Phthalate metabolites were not associated with triglycerides or high-density lipoproteins. Further, longitudinal studies are needed to confirm these associations and to assess opportunities for intervention.

Association of arteriosclerosis index and oxidative stress markers in school children

BACKGROUND

Recent years have seen increased numbers of children with conditions that contribute strongly to atherosclerotic disease, such as passive smoking, obesity, and dyslipidemia. In the present study, we evaluated the utility of non-invasive urinary markers in preventing lifestyle-related diseases by comparing lipid metabolism-related parameters with oxidative stress markers in school children.

METHODS

Subjects were 85 first-grade students. The variables examined included the smoking in subjects' household; exercise habits; height and weight; blood pressure; and plasma total cholesterol, high-density lipoprotein cholesterol, triglyceride, leptin, blood sugar, urinary cotinine, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and 8-isoprostaglandin F2α (IsoP).

RESULTS

Of the subjects, 10.6% were obese (% overweight ≥ 20%), 3.5% had a high-risk arteriosclerosis index (AI; 3 ≤ AI < 5), and 29.4% were passive smokers. No significant differences were seen between boys and girls for any of the measurement parameters. Both urinary 8-OHdG (6.8-24.5 ng/mg creatinine) and IsoP (0.9-7.4 ng/mg creatinine) were detected in all subjects, and a significant positive correlation was seen between the two markers. On multiple regression analysis using AI as an objective variable and all non-invasive markers as explanatory variables, urinary IsoP correlated most strongly with AI (P ≤ 0.01).

CONCLUSIONS

Risk factors for atherosclerosis in adults, such as obesity and hypercholesterolemia, are associated with oxidative stress and inflammation. The present findings of the strongest correlation between urinary IsoP and AI suggest that urinary IsoP may serve as a non-invasive and effective early marker in predicting risk in children of developing lifestyle-related diseases.

Manganese superoxide dismutase and oxidative stress modulation

Oxidative stress is characterized by imbalanced reactive oxygen species (ROS) production and antioxidant defenses. Two main antioxidant systems exist. The nonenzymatic system relies on molecules to directly quench ROS and the enzymatic system is composed of specific enzymes that detoxify ROS. Among the latter, the superoxide dismutase (SOD) family is important in oxidative stress modulation. Of these, manganese-dependent SOD (MnSOD) plays a major role due to its mitochondrial location, i.e., the main site of superoxide (O(2)(·-)) production. As such, extensive research has focused on its capacity to modulate oxidative stress. Early data demonstrated the relevance of MnSOD as an O(2)(·-) scavenger. More recent research has, however, identified a prominent role for MnSOD in carcinogenesis. In addition, SOD downregulation appears associated with health risk in heart and brain. A single nucleotide polymorphism which alters the mitochondria signaling sequence for the cytosolic MnSOD form has been identified. Transport into the mitochondria was differentially affected by allelic presence and a new chapter in MnSOD research thus begun. As a result, an ever-increasing number of diseases appear associated with this allelic variation including metabolic and cardiovascular disease. Although diet and exercise upregulate MnSOD, the relationship between environmental and genetic factors remains unclear.

Honey and cardiovascular risk factors, in normal individuals and in patients with diabetes mellitus or dyslipidemia

Diabetes mellitus, hypercholesteremia, hypertension (HTN), and obesity are well-known risk factors for cardiovascular diseases (CVD). Various medications are currently in use for management of these comorbidities. Undesirable side effects are unavoidable and the ultimate and ideal goal is hardly achieved. Honey and other bee products are widely used in traditional medicine for management of many diseases. Others and the authors have found potent biological activities of these products. Honey is now reintroduced in modern medicine as part of wound and burn management. Honey has antioxidant, anti-inflammatory, and antimicrobial activities. More studies are exploring other aspects of honey activity such as its effect on blood sugar, body weight, lipid profile, C-reactive protein, nitric oxide, proinflammatory prostaglandins, and homocysteine. Growing evidence and scientific data support the use of honey in patients with diabetes, HTN, dyslipidemia, obesity, and CVD. This review discusses clinical and preclinical studies on potential influence of honey on diabetes mellitus and cardiovascular risk factors, and emphasizes the importance of conducting more clinical and controlled studies.

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.

Urinary phthalates are associated with higher blood pressure in childhood

OBJECTIVE

To examine associations of urinary phthalate levels with blood pressure (BP) and serum triglyceride and lipoprotein levels in children.

STUDY DESIGN

We performed a cross-sectional analysis of a subsample of US children aged 6-19 years who participated in the National Health and Nutrition Examination Survey between 2003 and 2008. We quantified exposure to 3 families of phthalates--low molecular weight, high molecular weight and di-2-ethylhexylphthalate (DEHP)--based on molar concentration of urinary metabolites. We assessed descriptive, bivariate, and multivariate associations with BP and lipid levels.

RESULTS

Controlling for an array of sociodemographic and behavioral factors, as well as diet and body mass index, levels of metabolites of DEHP, a phthalate commonly found in processed foods, were associated with higher age-, sex-, and height-standardized BP. For each log unit (roughly 3-fold) increase in DEHP metabolites, a 0.041 SD unit increase in systolic BP z-score was identified (P = .047). Metabolites of low molecular weight phthalates commonly found in cosmetics and personal care products were not associated with BP. Phthalate metabolites were not associated with triglyceride levels, high-density lipoprotein level, or prehypertension.

CONCLUSIONS

Dietary phthalate exposure is associated with higher systolic BP in children and adolescents. Further work is needed to confirm these associations, as well as to evaluate opportunities for intervention.

Oxidative stress and cardiovascular risk in overweight children in an exercise intervention program

BACKGROUND

This study aimed to determine whether oxidative stress was related to cardiovascular risk indices in children, and whether an exercise intervention would reduce oxidative stress.

METHODS

A randomized trial of two different doses of exercise and a no-exercise control group included 112 overweight and obese children, 7-11 years old. Plasma isoprostane levels were obtained at baseline and after the intervention. Cross-sectional analysis of oxidative stress and metabolic markers at baseline was performed. The effect of the exercise training on oxidative stress was tested.

RESULTS

Lower isoprostane levels were observed in blacks. At baseline, isoprostane was positively related to measures of fatness (BMI, waist circumference, percent body fat), insulin resistance and β-cell function (fasting insulin, insulin area under the curve, Matsuda index, disposition index, oral disposition index), and several lipid markers (low-density lipoprotein, triglycerides, total cholesterol), and inversely with fitness [peak oxygen consumption (VO(2))], independent of race, sex, and cohort. No relation was found with visceral fat, blood pressure, or glycemia. Independent of percent body fat, isoprostane predicted triglycerides, β=0.23, total cholesterol-to-high-density lipoprotein (TC/HDL) ratio, β=0.23, and insulin resistance (insulin area under the curve, β=0.24, Matsuda index, β=-0.21, oral disposition index, β=0.33). Exercise did not reduce oxidative stress levels, despite reduced fatness and improved fitness in these children.

CONCLUSIONS

Isoprostane levels were related to several markers of cardiovascular risk at baseline; however, despite reduced fatness and improved fitness, no effect of exercise was observed on isoprostane levels. To our knowledge, this is the first report in children to demonstrate a correlation of oxidative stress with disposition index, fitness, and TC/HDL ratio, the first to test the effect on oxidative stress of an exercise intervention that reduced body fat, and the first such exercise intervention study to include a substantial proportion of black children.

Honey supplementation in spontaneously hypertensive rats elicits antihypertensive effect via amelioration of renal oxidative stress

Oxidative stress is implicated in the pathogenesis and/or maintenance of elevated blood pressure in hypertension. This study investigated the effect of honey on elevated systolic blood pressure (SBP) in spontaneously hypertensive rats (SHR). It also evaluated the effect of honey on the amelioration of oxidative stress in the kidney of SHR as a possible mechanism of its antihypertensive effect. SHR and Wistar Kyoto (WKY) rats were randomly divided into 2 groups and administered distilled water or honey by oral gavage once daily for 12 weeks. The control SHR had significantly higher SBP and renal malondialdehyde (MDA) levels than did control WKY. The mRNA expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and glutathione S-transferase (GST) were significantly downregulated while total antioxidant status (TAS) and activities of GST and catalase (CAT) were higher in the kidney of control SHR. Honey supplementation significantly reduced SBP and MDA levels in SHR. Honey significantly reduced the activities of GST and CAT while it moderately but insignificantly upregulated the Nrf2 mRNA expression level in the kidney of SHR. These results indicate that Nrf2 expression is impaired in the kidney of SHR. Honey supplementation considerably reduces elevated SBP via amelioration of oxidative stress in the kidney of SHR.

Resting heart rate as a predictor of metabolic dysfunctions in obese children and adolescents

BACKGROUND

Recent studies have identified that a higher resting heart rate (RHR) is associated with elevated blood pressure, independent of body fatness, age and ethnicity. However, it is still unclear whether RHR can also be applied as a screening for other risk factors, such as hyperglycemia and dyslipidemia. Thus, the purpose of the presented study was to analyze the association between RHR, lipid profile and fasting glucose in obese children and adolescents.

METHODS

The sample was composed of 180 obese children and adolescents, aged between 7-16 years. Whole-body and segmental body composition were estimated by Dual-energy X-ray absorptiometry. Resting heart rate (RHR) was measured by heart rate monitors. The fasting blood samples were analyzed for serum triglycerides, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and glucose, using the colorimetric method.

RESULTS

Fasting glucose, TC, triglycerides, HDL-C, LDL-C and RHR were similar in both genders. The group of obese subjects with a higher RHR presented, at a lower age, higher triglycerides and TC. There was a significant relationship between RHR, triglycerides and TC. In the multivariate model, triglycerides and TC maintained a significant relationship with RHR independent of age, gender, general and trunk adiposity. The ROC curve indicated that RHR has a high potential for screening elevated total cholesterol and triglycerides as well as dyslipidemia.

CONCLUSION

Elevated RHR has the potential to identify subjects at an increased risk of atherosclerosis development.

Cysteine and obesity: consistency of the evidence across epidemiologic, animal and cellular studies

PURPOSE OF REVIEW

The concentrations of several plasma amino acids increase in obesity. Notably, plasma total concentrations of the sulphur amino acid cysteine (tCys) are linearly associated with fat mass in large population studies. Animal and cellular experiments support the concept that cysteine may be obesogenic. Here we review experimental and epidemiologic findings linking cysteine and related compounds with fat regulation and obesity.

RECENT FINDINGS

tCys, and to a lesser extent cystathionine, are the only plasma sulphur amino acids consistently associated with human obesity, whereas glutathione is inversely associated with BMI. Supplementing cyste(i)ne in rodents decreases energy expenditure and promotes adiposity, whereas defects of cysteine-synthesizing enzymes decrease body weight. In adipocytes, cysteine inhibits lipolysis and promotes lipogenesis via H2O2 production. Unlike most plasma amino acids, tCys levels do not decrease with gastric bypass-induced weight loss, further supporting the concept that elevated cysteine may be a cause, not a consequence of obesity. Although cysteine products (glutathione, taurine and H2S) are altered in obesity, they do not appear to explain cysteine's effects on body weight.

SUMMARY

Cellular, animal and epidemiologic data are consistent with the view that cysteine is obesogenic. Targeted research linking in-vitro and in-vivo findings is needed to elucidate mechanisms involved.

Obesity and cardiovascular risk in children and adolescents

The global prevalence of overweight and obesity in children and adolescents has increased substantially over the past several decades. These trends are also visible in developing economies like India. Childhood obesity impacts all the major organ systems of the body and is well known to result in significant morbidity and mortality. Obesity in childhood and adolescence is associated with established risk factors for cardiovascular diseases and accelerated atherosclerotic processes, including elevated blood pressure (BP), atherogenic dyslipidemia, atherosclerosis, metabolic syndrome, type II diabetes mellitus, cardiac structural and functional changes and obstructive sleep apnea. Probable mechanisms of obesity-related hypertension include insulin resistance, sodium retention, increased sympathetic nervous system activity, activation of the renin-angiotensin-aldosterone system and altered vascular function. Adiposity promotes cardiovascular risk clustering during childhood and adolescence. Insulin resistance has a strong association with childhood obesity. A variety of proinflammatory mediators that are associated with cardiometabolic dysfunction are also known to be influenced by obesity levels. Obesity in early life promotes atherosclerotic disease in vascular structures such as the aorta and the coronary arteries. Childhood and adolescent adiposity has strong influences on the structure and function of the heart, predominantly of the left ventricle. Obesity compromises pulmonary function and increases the risk of sleep-disordered breathing and obstructive sleep apnea. Neglecting childhood and adolescent obesity will compromise the cardiovascular health of the pediatric population and is likely to result in a serious public health crisis in future.

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.