Vascular endothelial and smooth muscle function relates to body mass index and glucose in obese and nonobese children

Association of Biomarkers for Dyslipidemia, Inflammation, and Oxidative Stress with Endothelial Dysfunction in Obese Youths: A Case-Control Study

Objective

The United Arab Emirates (UAE), with its characteristic local population, geography, and history, presents several risk factors for cardiovascular diseases (CVDs) in obese individuals. Obesity and its associated complications, including diabetes, atherogenic dyslipidemia, and CVDs leading to significant health risks. In the present study, "Youths" defined as young people between 18 and 22 years. We assessed dyslipidemia, inflammation, and oxidative stress biomarker levels and their association with endothelial dysfunction (ED) in both overweight/obese and normal weight youths of UAE.

Methods

There were 160 youths with overweight/obese (BMI ≥ 25 kg/m2) patients and healthy age- and sex-matched normal weight (BMI ≤ 24.9 kg/m2) as controls participated in this study. The anthropometric data and blood samples were collected to assess the biomarkers for dyslipidemia, inflammation, oxidative stress, ED from all the youths.

Results

The overall mean age and male-to-female ratio were 20±1.5years and 1.0:1.2, respectively. There was statistically significant difference in HDL-C (p<0.001), triglycerides (TG) (p<0.001), ApoA (p=0.002), ApoB/ApoA ratio (p=0.009) between the overweight/obese and normal weight youths. Among, inflammatory markers: hs-CRP, IL-6, TNF-α also showed significant p<0.001 and oxidative stress markers: DNA/RNA Damage, catalase and nitric oxide (NO) showed significant p<0.001 between groups. Spearman correlation of ED markers with lipid profile markers showed Vitamin C levels positively correlated with HDL-C (p<0.001) and negatively correlated with glucose (p<0.001). ICAM-1showed significant negative correlation with HDL-C (p<0.01) and ApoA (p<0.001) but positive correlation with TG (p<0.01) and HbA1c (p<0.001) among groups. Spearman correlation of ED markers with inflammatory/oxidative stress biomarkers showed Vitamin C levels negatively correlated with ferritin (p < 0.001), NO (p < 0.001), GGT (p < 0.001), and ALT (p < 0.001) levels. The ICAM-1showed significant positive correlation with hs-CRP (p < 0.01), IL-6 (p < 0.001), TNF-α (p < 0.01), GGT (p < 0.05), and ALT (p < 0.05) in both groups.

Conclusion

This study revealed a strong link between the biomarkers of dyslipidemia, inflammation, and oxidative stress with ED in overweight/obese patients. This study might be used to predict future cardiovascular events in this population.

A combination of metformin and insulin improve cardiovascular and cerebrovascular risk factors in individuals with type 1 diabetes mellitus

BACKGROUND

This study aims to further clarify whether the addition of metformin to insulin treatment improve cardiovascular and cerebrovascular risk factors in individuals with T1DM.

METHODS

Electronic databases were searched for randomized controlled trials in which the efficacy and safety of metformin were compared with those of a placebo for risk factors of cardiovascular and cerebrovascular disease among individuals with T1DM, and a meta-analysis was conducted.

RESULTS

Thirteen cardiovascular studies were identified. In the metformin group, mean carotid intimal media thickness was significantly reduced by 0.03 mm, ascending aortic pulse wave velocity by 6.3 m/s, descending aortic wall shear stress by 1.77 dyn/cm² (P = 0.02), insulin daily dose by 0.05 U/kg/d, body weight by 2.27 kg, fat-free mass by 1.32 kg, body mass index by 0.58 kg/m², hip circumference by 0.29 m, and low-density lipoprotein by 0.16 mmol/L, all above are P < 0.05. In the metformin group, flow-mediated dilation was increased by 1.29 %, glucose infusion rate/insulin by 18.22 mg/(kg⋅min)/μIU/μL, and waist-to-hip ratio by 0.02, all above are P < 0.00001. The metformin group showed no differences in blood pressure, reactive hyperemia index, waist circumference, triglyceride, total cholesterol, high-density lipoprotein cholesterol, or body mass index Z score. For cerebrovascular studies were identified. But none of them had a risk factor assessment.

CONCLUSIONS

Metformin can ameliorate cardiovascular and cerebrovascular risk factors through non-hypoglycemic multiple pathways in individuals with T1DM.

Obesity and Endothelial Function

Obesity is a major public health problem and is related to increasing rates of cardiovascular morbidity and mortality. Over 1.9 billion adults are overweight or obese worldwide and the prevalence of obesity is increasing. Obesity influences endothelial function through obesity-related complications such as hypertension, dyslipidemia, diabetes, metabolic syndrome, and obstructive sleep apnea syndrome. The excess fat accumulation in obesity causes adipocyte dysfunction and induces oxidative stress, insulin resistance, and inflammation leading to endothelial dysfunction. Several anthropometric indices and imaging modalities that are used to evaluate obesity have demonstrated an association between obesity and endothelial function. In the past few decades, there has been great focus on the mechanisms underlying endothelial dysfunction caused by obesity for the prevention and treatment of cardiovascular events. This review focuses on pathophysiological mechanisms of obesity-induced endothelial dysfunction and therapeutic targets of obesity.

Proteolytic activation of anti-Müllerian hormone is suppressed in adolescent girls

PURPOSE

The ratio of the anti-Müllerian hormone (AMH) precursor (proAMH) to active AMH (AMH_N,C) is higher in childhood than in adulthood but has never been quantified during adolescence. The ratio of proAMH to total AMH (AMH prohormone index, API) was examined during the puberty in healthy girls. The API was also compared between girls with and without polycystic ovary syndrome (PCOS) to determine if there were differences that could assist in PCOS diagnosis during adolescence.

METHODS

Total AMH and proAMH were measured by immunoassay in a single-centre, cross-sectional observational study; 61 controls and 29 girls with PCOS were included in the study (age range 8-21 years). The API was calculated as proAMH as a percentage of total AMH. Differences in API between control and PCOS subjects and across age-groups were examined by Welch's ANOVA. The relationship between API and a range of metabolic parameters was examined by Pearson correlation.

RESULTS

The API in healthy females increased between the ages of 10~15 years and declined from 15~20 years (p < 0.001). The API was negatively correlated with body mass index in the control (p = 0.04) and PCOS groups (p = 0.007). The API was associated with factors related to adiposity and lipid metabolism. The API was not significantly different in control girls and girls with PCOS.

CONCLUSIONS

Higher API during adolescence suggests that proteolytic activation of proAMH is suppressed during this life stage. API was not different between control girls and girls with PCOS indicating that it is not useful in diagnosis of PCOS during adolescence.

Decreased Flow-Mediated Dilatation in Children With Type 1 Diabetes: A Systematic Review and Meta-Analysis

Type 1 diabetes (T1DM) is a strong risk factor for the development of cardiovascular disease. Flow-mediated dilatation (FMD) is an early noninvasive marker of endothelial function and it predicts future cardiovascular disease. However, the changes in FMD among T1DM children are still controversial. The present meta-analysis aimed to investigate whether FMD is impaired in children with T1DM. PubMed, EMBASE, Cochrane library, and Web of Science were searched for studies comparing FMD in children with T1DM and healthy controls. The Newcastle-Ottawa quality assessment scale for case-control studies was used to assess study quality. Data were pooled using a random effects models to obtain the weighted mean differences (WMD) in FMD and 95% CIs. Overall, 19 studies with 1245 patients and 872 healthy controls were included in this meta-analysis. Children with T1DM had significantly lower FMDs compared with healthy controls (WMD: -2.58; 95% CI: -3.36 to -1.81; P < .001). Meta-regression analysis revealed that low-density lipoprotein cholesterol levels impacted the observed difference in FMD between T1DM and healthy children. This meta-analysis showed that T1DM children have impaired endothelial function, which indicates they are at higher risk of developing cardiovascular disease in later life.

Determinants of Intima-Media Thickness in the Young: The ALSPAC Study

OBJECTIVES

This study characterized the determinants of carotid intima-media thickness (cIMT) in a large (n > 4,000) longitudinal cohort of healthy young people age 9 to 21 years.

BACKGROUND

Greater cIMT is commonly used in the young as a marker of subclinical atherosclerosis, but its evolution at this age is still poorly understood.

METHODS

Associations between cardiovascular risk factors and cIMT were investigated in both longitudinal (ages 9 to 17 years) and cross-sectional (ages 17 and 21 years) analyses, with the latter also related to other measures of carotid structure and stress. Additional use of ultra-high frequency ultrasound in the radial artery at age 21 years allowed investigation of the distinct layers (i.e., intima or media) that may underlie observed differences.

RESULTS

Fat-free mass (FFM) and systolic blood pressure were the only modifiable risk factors positively associated with cIMT (e.g., mean difference in cIMT per 1-SD increase in FFM at age 17: 0.007 mm: 95% confidence interval [CI]: 0.004 to 0.010; p < 0.001), whereas fat mass was negatively associated with cIMT (difference: -0.0032; 95% CI: 0.004 to -0.001; p = 0.001). Similar results were obtained when investigating cumulative exposure to these factors throughout adolescence. An increase in cIMT maintained circumferential wall stress in the face of increased mean arterial pressure when increases in body mass were attributable to increased FFM, but not fat mass. Risk factor-associated differences in the radial artery occurred in the media alone, and there was little evidence of a relationship between intimal thickness and any risk factor.

CONCLUSIONS

Subtle changes in cIMT in the young may predominantly involve the media and represent physiological adaptations as opposed to subclinical atherosclerosis. Other vascular measures may be more appropriate for the identification of arterial disease before adulthood.

Circulating chemerin level may be associated with early vascular pathology in obese children without overt arterial hypertension - preliminary results

Background Elevated chemerin level is observed in patients with arterial hypertension. The aim of the study was to determine the relationship between chemerin level, and parameters of blood pressure and arterial stiffness in children and adolescents with obesity but without arterial hypertension. Methods In 23 children with obesity (13 girls, mean age 9.3, SD 1.9, mean BMI SDS 3.9, SD 1.7) 24 h ABPM (Spacelabs 90,217, USA), common carotids and abdominal aorta intima media thickness measurements (Voluson 730, GE Medical System 8.5 and 3.5 MHz probes), body composition analysis (Tanita BC 418 S MA, Tokyo, Japan) were performed. Glucose, triglycerides, total, LDL and HDL cholesterol, liver enzymes, uric acid, creatinine, sodium, insulin and chemerin levels were assessed in blood sample taken after a 12-h fasting period. Results There was a significant correlation of circulating chemerin level with systolic blood pressure load in ABPM (r=0.5, p<0.05). Conclusion Elevated chemerin level may be associated with increased systolic blood pressure in obese children.

Urinary Biomarkers of Inflammation and Oxidative Stress Are Elevated in Obese Children and Correlate with a Marker of Endothelial Dysfunction

Obesity is a state of chronic low-level inflammation closely associated with oxidative stress. Childhood obesity is associated with endothelial dysfunction, inflammation, and oxidative stress markers individually. This study was aimed at determining the association between the biomarkers of inflammation, oxidative stress, and endothelial dysfunction in urine samples of healthy, overweight, and obese children. Eighty-eight elementary school children aged between 6 and 10 years participated in this study. Anthropometric measurements were measured using WHO recommendations. The biomarkers of low-grade inflammation such as C-reactive protein (CRP), interleukin-6 (IL-6), and α-1-acid glycoprotein (AGP); oxidative stress markers such as 8-isoprostane and 8-hydroxy-2'-deoxyguanosine (8-OHdG); and endothelin-1 (ET-1) were analyzed in urine samples. The area under the curve (AUC) by the receiver operating characteristics (ROC) was analyzed to identify the best urinary biomarker in childhood obesity. Linear regression and Pearson correlation were analyzed to determine the association between the parameters. The obese participants have significantly increased levels of CRP, AGP, IL-6, and 8-isoprostane compared to normal-weight participants. The overweight participants had significantly increased levels of ET-1 and 8-OHdG but not the obese group compared to the NW group. The AUC for urinary CRP (AUC: 0.847, 95% CI: 0.765-0.930; p < 0.0001) and 8-isoprostane (AUC: 0.857, 95% CI: 0.783-0.932; p < 0.0001) showed a greater area under ROC curves compared to other inflammatory and oxidative markers. The urinary CRP and 8-isoprostane significantly correlated with the obesity measures (body mass index, waist circumference, and waist-to- height ratio) and ET-1, inflammatory, and oxidative markers. The increased urinary inflammatory markers and 8-isoprostane can serve as a noninvasive benchmark for early detection of the risk of developing cardiovascular disease.

Eating frequency and weight status in Portuguese children aged 3-9 years: results from the cross-sectional National Food, Nutrition and Physical Activity Survey 2015-2016

OBJECTIVE

To evaluate daily eating frequency (main meals and snacks) in relation to weight status in children aged 3-9 years, representative of the Portuguese population.

DESIGN

Cross-sectional study. Dietary intake was estimated as the mean of two non-consecutive days of food diaries, followed by face-to-face interviews. Weight and height were measured by trained observers. Eating occasions (EO) were defined by the children's caregiver; an EO was considered separate if the time of consumption was different from other EO and it provided at least 209 kJ (50 kcal). Main meals defined as 'breakfast', 'lunch' and 'dinner' could be selected only once per day. The remaining EO were considered snacks. The association between eating frequency and overweight/obesity was evaluated through logistic regressions weighted for the population distribution.

SETTING

National Food, Nutrition and Physical Activity Survey of the Portuguese population, 2015-2016.

PARTICIPANTS

Portuguese children aged 3-9 years with complete dietary data and anthropometric measurements (n 517).

RESULTS

Overall, the number of daily EO ranged from 3·5 to 11, and on average children had 5·7 daily EO. After adjustment for child's sex, age and total energy intake, and considering only plausible energy intake reporters, having < 3 snacks/d was positively associated with being overweight/obese (OR = 1·98; 95 % CI 1·00, 3·90), compared with having ≥ 3 snacks/d.

CONCLUSIONS

Lower daily frequency of EO was associated with increased odds of being overweight or obese in children. A higher eating frequency, maintaining the same energy intake, seems to contribute to a healthy body weight in children.

Associations of sex, age and adiposity in endothelium-independent dilation in children

OBJECTIVE

To examine the association of age, sex, and obesity status on endothelial-independent dilation (EID) among children and adolescents.

STUDY DESIGN

This study examined 264 children (143 males) between 8 to 18 years old (mean  ±  SD: age  =  14.3  ±  2.7 years). Endothelial-independent dilation was assessed via ultrasound imaging of the brachial artery following administration of 0.3 milligrams of sublingual nitroglycerin. A one-way analysis of variance with Bonferroni post hoc comparisons assessed sex-differences in percent peak EID dilation (EID%-peak) and EID area under the curve (EID%-AUC), while analysis of covariance (ANCOVA) adjusted for race, age, body mass index percentile (BMI-percentile), and brachial artery diameter. Multiple linear regression evaluated the association of sex, age, BMI-percentile, percent body fat (%BF), and brachial artery diameter on EID.

RESULTS

Prior to adjustment, EID%-peak was significantly higher among females than males (mean  ±  SE: 26.9  ±  0.5% versus 22.9  ±  0.6%, p  <  0.001, respectively); similar findings for EID%-AUC (4214%  ±  105%·s versus 3398%  ±  97%·s, p  <  0.001) were observed. After adjusting for covariates, EID%-AUC remained consistent (p  =  0.03) while EID%-peak was not significantly different between sexes (p  =  0.21). EID%-peak was significantly higher among normal weight compared to obese participants (p  =  0.04), while no differences were observed between obesity status after adjustment for brachial artery diameter (p  =  0.64). Both unadjusted (p  =  0.16) and adjusted EID%-AUC (p  =  0.24) was not significantly different between obesity status. BMI-percentile was not associated with EID%-peak (p  =  0.76) or EID%-AUC (p  =  0.30). Additionally, %BF was not associated with EID%-peak (p  =  0.56) or EID%-AUC (p  =  0.15). After adjusting for brachial artery diameter, BMI-percentile, and age, males had lower EID%-AUC (p  =  0.03) and lower but not significant EID%-peak (p  =  0.21).

SIGNIFICANCE

Vascular smooth muscle function was significantly lower among male children and adolescents, which is suggestive that impaired EID and increased cardiovascular disease risk among males may begin in childhood. Interestingly, obesity status and BMI-percentile was not associated with EID in children and adolescents after adjusting for brachial artery diameter.

Dietary sodium intake relates to vascular health in children with type 1 diabetes

BACKGROUND AND OBJECTIVE

Children with type 1 diabetes (T1D) have vascular dysfunction and frequently struggle to adhere to dietary recommendations. Limited data exist for the vascular consequences of poor diet quality in children. We aimed to evaluate the association between dietary components and vascular function in children with T1D.

METHODS

Cross-sectional study including 90 children (13.6 [3.5] years, 41 boys) with T1D. They had evaluation of dietary micro and macronutrients (Australian Child and Adolescent Eating Survey), vascular endothelial and smooth muscle function (flow-mediated dilatation and glyceryl trinitrate mediated dilatation [GTN], respectively), clinical and biochemical variables.

RESULTS

Children had a sodium intake of 3.013 (0.76) (mean [SD]) g/day. Vascular smooth muscle dysfunction, as measured by GTN, related to higher daily sodium intake (r = -0.31, P = .003), independent of the inverse relationships between GTN and total energy (r = -0.30, P = .005) and fat intake (r = -0.28, P = .007). Multiregression model showed that an increase in 1 g of daily sodium intake was independently associated with a deterioration of 3 percentage units in GTN (95% CI -4.3, -0.9; P = .003). There was an association between sodium intake and systolic blood pressure after adjustment for age and gender (regression coefficient 2.4; 95% CI 0.5, 4.3; P = .01).

CONCLUSIONS

High dietary sodium intake in children with T1D is common and relates to vascular dysfunction, independently of other dietary intake, blood pressure, and glycemic control.

Evaluation of endothelial dysfunction, endothelial plasma markers, and traditional metabolic parameters in children with adiposity

BACKGROUND/PURPOSE

To investigate the correlations among endothelial function assessment parameters, asymmetric dimethylarginine (ADMA)-related biomarkers, and traditional risk factors in adipose children.

METHODS

We enrolled adipose children aged 7-18 years between July 2014 and August 2016 as well as normal-weight controls from the outpatient clinic. Vascular measurements including echocardiography, carotid intima media thickness, pulse wave velocity (PWV), and flow-mediated dilation (FMD) were measured. Venous blood samples including traditional metabolic and endothelial dysfunction parameters were analyzed. Participants were grouped as adipose vs. normal-weight and as adipose with hypertension vs. adipose without hypertension. Clinical presentations, laboratory data, and cardiovascular measurement were compared.

RESULTS

Of the 105 enrolled children, 85 were adipose. Adipose children had higher systolic blood pressure, larger left ventricular (LV) mass, and adverse traditional metabolic biomarkers. FMD was significantly reduced (8.25 (5.32-12.06) % vs. 12.49 (7.18-16.58) %, p = 0.018) in the adipose group. PWV was markedly increased (4.65 (4.2-5.5) m/sec vs. 3.95 (3.38-4.35) m/sec, p < 0.001) in the hypertensive adipose children. Endothelial dysfunction parameters were not significantly changed in this study.

CONCLUSION

Adipose children were at higher risk of hypertension and LV hypertrophy. FMD, PWV and traditional cardiovascular biomarkers can detect subtle vascular changes. Hypertension is an important sign of arterial involvement in adipose children. Although ADMA-related biomarkers were not statistically significant, future studies are needed to confirm its correlation with adiposity and hypertension in children. The early detection and prevention of endothelial dysfunction may decrease the rate of progression to cardiovascular consequences in later life.

Effect of Metformin on Vascular Function in Children With Type 1 Diabetes: A 12-Month Randomized Controlled Trial

CONTEXT

Children with type 1 diabetes have vascular dysfunction preceding atherosclerosis. Early interventions are needed to reduce cardiovascular disease.

OBJECTIVE

To evaluate the effect of metformin on vascular function in children with type 1 diabetes.

DESIGN

Twelve-month double-blind, randomized, placebo-controlled trial.

SETTING

Tertiary pediatric diabetes clinic.

PARTICIPANTS

Ninety children (8 to 18 years of age), >50th percentile body mass index (BMI), with type 1 diabetes.

INTERVENTION

Metformin (up to 1 g twice a day) or placebo.

MAIN OUTCOME MEASURE

Vascular function measured by brachial artery ultrasound [flow-mediated dilatation/glyceryl trinitrate-mediated dilatation (GTN)].

RESULTS

Ninety participants were enrolled [41 boys, 13.6 (2.5) years of age, 45 per group], 10 discontinued intervention, and 1 was lost to follow-up. On metformin, GTN improved, independent of glycosylated hemoglobin (HbA1c), by 3.3 percentage units [95% confidence interval (CI) 0.3, 6.3, P = 0.03] and insulin dose reduced by 0.2 U/kg/d (95% CI 0.1, 0.3, P = 0.001) during 12 months, with effects from 3 months. Metformin had a beneficial effect on HbA1c at 3 months (P = 0.001) and difference in adjusted HbA1c between groups during 12 months was 1.0%; 95% CI 0.4, 1.5 (10.9 mmol/mol; 95% CI 4.4, 16.4), P = 0.001. There were no effects on carotid/aortic intima media thickness, BMI, lipids, blood pressure, or other cardiovascular risk factors. Median (95% CI) adherence, evaluated by electronic monitoring, was 75.5% (65.7, 81.5), without group differences. More gastrointestinal side effects were reported on metformin (incidence rate ratio 1.65, 95% CI 1.08, 2.52, P = 0.02), with no difference in hypoglycemia or diabetic ketoacidosis.

CONCLUSIONS

Metformin improved vascular smooth muscle function and HbA1c, and lowered insulin dose in type 1 diabetes children. These benefits and good safety profile warrant further consideration of its use.

Children With Type 1 Diabetes Have Delayed Flow-Mediated Dilation

OBJECTIVES

Children with type 1 diabetes have accelerated atherosclerosis with early endothelial dysfunction as measured by reduced flow-mediated dilation (FMD) at 60 seconds postischemic stress (early FMD). Delayed dilation may also occur in the presence of cardiovascular risk factors and may be a more sensitive marker. No data exist that evaluate FMD beyond 60 seconds (delayed FMD) in children with type 1 diabetes. We aimed to compare early and delayed FMD in children with type 1 diabetes and in healthy children.

METHODS

We studied 66 children 13.5±2.8 years of age; 29 were males. Of the 66 children, 38 had type 1 diabetes, and 28 were healthy age- and gender-matched controls. Evaluation of brachial artery FMD was performed at 60 seconds (FMD_60s) and 120 seconds (FMD_120s) postischemic stress. Early FMD was defined as peak FMD_60s and delayed FMD as peak FMD_120s. RESULTS: Children with type 1 diabetes had diabetes durations of 5.4±4.6 years and median glycated hemoglobin levels of 8.8 (6.6 to 14)% (73 [49 to 130] mmol/mol). Of the children, 8 with type 1 diabetes and 1 healthy child had delayed FMD; a relationship was seen between the prevalence of early FMD and delayed FMD in children with type 1 diabetes and healthy children, respectively (p=0.019). Children with type 1 diabetes and delayed FMD had lower FMD_60s than children without delayed FMD (2.50±3.61 vs. 6.14±3.83 percentage units; p=0.02). Children with type 1 diabetes had lower FMD_60s than healthy children (5.38±4.0 percentage units; p=0.03) but not FMD_120s (7.56±3.5 percentage units; p=0.47).

CONCLUSIONS

Delayed FMD patterns occur in children with type 1 diabetes and detect children who have more severe vascular abnormalities. The standard FMD_60s remains the better marker to identify children at increased risk for cardiovascular disease.

Impact of Lifestyle Intervention on HDL-Induced eNOS Activation and Cholesterol Efflux Capacity in Obese Adolescent

Background. Endothelial dysfunction occurs in obese children and adolescent and is regarded as a key step in the development of atherosclerosis. Important components for the development of endothelial dysfunction are reduced activity of endothelial nitric oxide synthase (eNOS) and an increase in cholesterol deposition in the vessel wall, due to reduced reverse cholesterol transport (RCT) activity. High density lipoprotein (HDL) exhibits antiatherosclerotic properties including modulation of eNOS activity and cholesterol efflux capacity. Lifestyle intervention programs can modify endothelial dysfunction in obese adolescents, but their impact on HDL-mediated eNOS activation and RCT is unknown so far. Methods. Obese adolescents (15 ± 1 years, BMI > 35 kg/m²) where randomized either to an intervention group (IG, n = 8; restricted diet and exercise) or to a usual care group (UC, n = 8). At the beginning and after 10 months of treatment HDL-mediated eNOS phosphorylation and cholesterol efflux capacity were evaluated. Results. Ten months of treatment resulted in a substantial weight loss (−31%), an improvement of endothelial function, and an increase in HDL-mediated eNOS-Ser¹¹⁷⁷ phosphorylation and RCT. A correlation between change in eNOS-Ser¹¹⁷⁷ phosphorylation or RCT and change in endothelial function was noted. Conclusion. A structured lifestyle intervention program improves antiatherosclerotic HDL functions, thereby positively influencing endothelial function.

Childhood obesity-related endothelial dysfunction: an update on pathophysiological mechanisms and diagnostic advancements

Childhood obesity jeopardizes a healthy future for our society's children as it is associated with increased cardiovascular morbidity and mortality later on in life. Endothelial dysfunction, the first step in the development of atherosclerosis, is already present in obese children and may well represent a targetable risk factor. Technological advancements in recent years have facilitated noninvasive measurements of endothelial homeostasis in children. Thereby this topic ultimately starts to get the attention it deserves. In this paper, we aim to summarize the latest insights on endothelial dysfunction in childhood obesity. We discuss methodological advancements in peripheral endothelial function measurement and newly identified diagnostic markers of vascular homeostasis. Finally, future challenges and perspectives are set forth on how to efficiently tackle the catastrophic rise in cardiovascular morbidity and mortality that will be inflicted on obese children if they are not treated optimally.

Relations among Adiposity and Insulin Resistance with Flow-Mediated Dilation, Carotid Intima-Media Thickness, and Arterial Stiffness in Children

OBJECTIVE

To determine the associations of adiposity and insulin resistance with measures of vascular structure and function in children.

STUDY DESIGN

A cross-sectional study included 252 children (age 15.1 ± 2.4 years; body mass index percentile 68.2 ± 26.5%; Tanner 2-5). Measurements of body fat percentage were obtained with dual-energy X-ray absorptiometry and visceral adipose tissue (VAT) with computed tomography. Insulin resistance was measured with hyperinsulinemic euglycemic clamp. Vascular measurements for endothelial function (brachial artery flow-mediated dilation [FMD]), vascular structure (carotid intima-media thickness [cIMT]), vascular stiffness (carotid incremental elastic modulus), and pulse wave velocity were analyzed by tertiles of adiposity and insulin resistance. Additional analyses with ANCOVA and linear regression were adjusted for Tanner, sex, race, and family relationship; FMD was also adjusted for baseline artery diameter.

RESULTS

FMD was positively associated with high adiposity (body mass index, body fat percentage, and VAT) (P < .01 all). Insulin resistance was not associated with FMD. cIMT was significantly, positively related to obesity, VAT, and insulin resistance (P < .05 all). No differences in carotid incremental elastic modulus and pulse wave velocity were observed in relation to adiposity or insulin resistance.

CONCLUSIONS

The findings suggest that adiposity is associated with higher FMD, and insulin resistance and VAT are associated with higher cIMT in children. Further research is needed to clarify the progression of these relations.

Challenges and Opportunities in the Management of Cardiovascular Risk Factors in Youth With Type 1 Diabetes: Lifestyle and Beyond

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in persons with type 1 diabetes (T1D). Specific risk factors associated with diabetes, such as hyperglycemia and kidney disease, have been demonstrated to increase the incidence and progression of CVD. Nevertheless, few data exist on the effects of traditional risk factors such as dyslipidemia, obesity, and hypertension on CVD risk in youth with T1D. Improvements in understanding and approaches to the evaluation and management of CVD risk factors, specifically for young persons with T1D, are desirable. Recent advances in noninvasive techniques to detect early vascular damage, such as the evaluation of endothelial dysfunction and aortic or carotid intima-media thickness, provide new tools to evaluate the progression of CVD in childhood. In the present review, current CVD risk factor management, challenges, and potential therapeutic interventions in youth with T1D are described.

Flow-mediated dilatation, using time course data, shows maturation of the brachial artery from young children to mid-adolescents

Flow-mediated dilatation (FMD) is a tool widely used to measure arterial responsiveness to sheer stress. However, there is scant literature to show how the peripheral arterial response changes as the vascular system matures. One reason for this is that the feasibility of measuring FMD in younger children has not been established. The aim of the present study was to assess brachial artery function at rest and during the FMD response after 4 min ischaemia of the forearm in children aged 6-15 years. Time to reach maximum FMD (FMDmax ) was found to be correlated with age (r = 0.4, P < 0.05), resting brachial artery diameter (r = 0.4, P < 0.05), height (r = 0.4, P < 0.05), body mass index (BMI; r = 0.45, P < 0.05), body surface area (r = 0.44, P < 0.05) and resting blood flow (r = 0.37, P < 0.05). However, there was no correlation between the traditional FMD response at 60 s or FMD maximal dilation and age, resting brachial artery diameter, height, weight, BMI, body surface area and resting blood flow. In conclusion, the time taken to reach the maximal dilation response is related to age, brachial artery luminal diameter and body habitus, but not the traditional measure of FMD response at 60 s or the maximal dilatation percentage.

Impact of Health Status and Lifestyle Modifications on Vascular Structure and Function in Children and Adolescents

Until recently cardiovascular disease is often thought of as a disease that manifests itself during middle age. Researchers and clinicians have begun to realize that the initial signs of cardiovascular disease begin early on in childhood with changes present in both vascular structure and function. This increased recognition has resulted in considerable effort to develop accurate and reliable methods to measure as well as track changes in vascular structure and function applicable to study this process in children and adolescents. Certain genetic abnormalities and chronic diseases, which present or emerge in childhood often result in meaningful changes to vascular structure and function, which aid in our understanding of the vascular disease process. In this review, we will discuss different methods of assessing vascular structure and function, the diseases in childhood associated with decrements and maladaptive changes in the vascular system, and whether modification of lifestyle (ie, weight loss, dietary and/or exercise changes) can affect vascular structure and function in children.

Lifetime risk: childhood obesity and cardiovascular risk

In a recent report, the worldwide prevalence of childhood obesity was estimated to have increased by 47% between 1980 and 2013. As a result, substantial concerns have been raised about the future burden of cardiovascular (CV) disease that could ensue. The purpose of this review is to summarize and interpret (i) the evidence linking early life obesity with adverse changes in CV structure and function in childhood, (ii) the lifetime risk for CV disease resulting from obesity in childhood, and (iii) the potential effects of lifestyle interventions in childhood to ameliorate these risks.

A NOS3 polymorphism determines endothelial response to folate in children with type 1 diabetes or obesity

OBJECTIVE

To determine the effect of polymorphisms in NOS3 and folate pathway enzymes on vascular function and folate status and endothelial response to folate in children with diabetes or obesity.

STUDY DESIGN

A total of 244 subjects (age 13.8 ± 2.8 years, 125 males) were studied for NOS3 and/or folate pathway polymorphisms using polymerase chain reaction/restriction fragment length polymorphism, including at baseline: 139 with type 1 diabetes; 58 with obesity; and 47 controls. The effect of NOS3 genotype on endothelial response to folate (5 mg) was assessed in 85 subjects with diabetes and 28 obese subjects who received active treatment during intervention trials. Vascular function (flow-mediated dilatation [FMD] and glyceryl trinitrate-mediated dilatation), clinical, and biochemical measurements were assessed at baseline and 8 weeks in folate intervention studies.

RESULTS

Folate pathway enzyme and NOS3 polymorphisms did not significantly affect baseline vascular function. The polymorphism in intron 4 of endothelial nitric oxide synthase altered endothelial response to folate significantly: in subjects with diabetes FMD improved by 6.4 ± 5% (insertion carriers) vs 2.3 ± 6.6% (deletion carriers), P = .01; in obese subjects FMD improved by 1.8 ± 5.4% (insertion carriers) and deteriorated by -3.2 ± 7.2% (deletion carriers), P = .05. More subjects carrying the insertion normalized FMD after folate supplementation (insertion 64% vs deletion 28%, χ(2) = 10.14, P = .001).

CONCLUSIONS

A NOS3 polymorphism predicts endothelial response to folate in children with diabetes or obesity, with implications for vascular risk and folate intervention studies.

Atherogenic dyslipidemia and cardiovascular risk factors in obese children

Childhood obesity when associated with serum lipoprotein changes triggers atherosclerosis. Evidences suggest that the atherosclerotic process begins in childhood and that the extent of early atherosclerosis of the aorta and coronary arteries can be associated with lipoprotein levels and obesity. Furthermore, many studies in childhood demonstrate an important relationship between parameters of insulin sensitivity, body fat distribution, and the development of lipid abnormalities. This review focuses on the most recent findings on the relationship between obesity, dyslipidemia, and cardiovascular risk in children.

Effects of a lifestyle program on vascular reactivity in macro- and microcirculation in severely obese adolescents

CONTEXT AND OBJECTIVE

This study aimed to comprehensively assess the macro- and microcirculation of severely obese adolescents (SOA) and normal-weight counterparts and to determine the longitudinal effects of weight loss on vascular function in SOA. DESIGN, SETTING, PARTICIPANTS, AND OUTCOME MEASURES: Seventeen SOA (body mass index z-score = 4.22 ± 0.73) and 19 puberty-matched normal-weight counterparts (body mass index z-score = -0.02 ± 1.04) were included. The SOA participated in a 4 month weight loss program. Brachial artery flow-mediated dilation and response to sublingual nitrate (nitrate-mediated dilation [NMD]) were assessed by high-resolution ultrasound. Microvascular reactivity was evaluated by laser Doppler flowmetry in response to NMD, iontophoresis of acetylcholine and sodium nitroprusside, and local hyperthermia. Plasma insulin, leptin, resistin, C-reactive protein, myeloperoxidase, and tissue plasminogen activator were measured.

RESULTS

At baseline, SOA had similar flow-mediated dilation and impaired NMD in the brachial artery compared to normal-weight adolescents. Similarly, peak responses to acetylcholine and sodium nitroprusside iontophoresis and to local hyperthermia were unaltered, whereas cutaneous blood flow after NMD was lower in the forearm microcirculation of SOA. All plasma measurements were significantly higher in SOA. After the 4-month program, SOA presented a weight reduction of 7.4 ± 3.1%, but neither brachial artery nor microvascular reactivity variables were improved. Significant decreases were detected in plasma leptin, myeloperoxidase, and tissue plasminogen activator.

CONCLUSIONS

Macro- and microvascular endothelial function are preserved in adolescents with severe obesity. Conversely, weight loss does not improve their impaired smooth muscle response to exogenous organic nitrate in both vascular beds, despite reducing plasma markers adversely related to vascular homeostasis.

Childhood obesity and cardiovascular dysfunction

Obesity-related cardiovascular disease in children is becoming more prevalent in conjunction with the rise in childhood obesity. Children with obesity are predisposed to an increased risk of cardiovascular morbidity and mortality in adulthood. Importantly, research in children with obesity over the last decade has demonstrated that children may exhibit early signs of cardiovascular dysfunction as a result of their excess adiposity, often independent of other obesity-related comorbidities such as dyslipidemia and insulin resistance. The clinical evidence is accumulating to suggest that the cardiovascular damage, once observed only in adults, is also occurring in obese children. The objective of this review is to provide a synopsis of the current research on cardiovascular abnormalities in children with obesity and highlight the importance and need for early detection and prevention programs to mitigate this potentially serious health problem.

Does metformin improve vascular health in children with type 1 diabetes? Protocol for a one year, double blind, randomised, placebo controlled trial

BACKGROUND

Cardiovascular disease is the leading cause of mortality in Type 1 diabetes (T1D). Vascular dysfunction is an early and critical event in the development of cardiovascular disease. Children with T1D have vascular dysfunction therefore early interventions to improve vascular health are essential to reduce cardiovascular mortality in T1D. Metformin is an insulin sensitising agent which is known to improve vascular health outcomes in type 2 diabetes (T2D) and other individuals with insulin resistance. It has been used safely in children and adolescents with T2D for over 10 years. This study aims to assess the effect of metformin on vascular health in children with T1D.

METHODS/DESIGN

This study is a 12 month, double blind, randomised, placebo controlled trial to determine the effect of metformin on vascular health in children (age 8-18) with T1D. The sample size is 76 with 38 children in the metformin group and 38 children in the placebo group. Vascular health and biochemical markers will be measured at baseline, 3, 6 and 12 months. Vascular function will be measured using flow mediated dilatation and glyceryl trinitrate mediated dilatation of the brachial artery and vascular structure will be measured with carotid and aortic intima media thickness, using standardised protocols.

DISCUSSION

This study will be the first to investigate the effect of metformin on vascular health in children with T1D. It will provide important information on a potential intervention to improve cardiovascular morbidity and mortality in this population at high risk from cardiovascular disease.

TRIAL REGISTRATION

Australia New Zealand Clinical Trials Registry ACTRN12611000148976.

Cardiovascular disease in childhood: the role of obesity

In recent years, childhood obesity is becoming an epidemic health problem. It is now evident from many studies that childhood obesity is correlated with adult excess weight status and the development of risk factors for cardiovascular diseases in adulthood, including hypertension, type 2 diabetes mellitus, dyslipidemia, and metabolic syndrome. The exposure to obesity and to the above risk factors during childhood subsequently lead to atherosclerotic development, such as altered vascular structure and function, although the mechanisms are still unclear. Several non-invasive, and thus easy-to-obtain measures of arterial structure and function, have been shown to be clinically useful in providing information about vasculature early in the course of atherosclerosis, including measurement of endothelial function, carotid intima media thickness, and arterial stiffness. The early detection of cardiovascular abnormalities is essential because the control of the atherogenic process is more effective during its early stages. The present review focuses on the cardiovascular consequences of obesity, on the mechanisms and the methods of measurement of endothelial dysfunction in obese children and adolescents, and on the ways of intervention for the improvement of vascular health.

Assessment of endothelial dysfunction in childhood obesity and clinical use

The association of obesity with noncommunicable diseases, such as cardiovascular complications and diabetes, is considered a major threat to the management of health care worldwide. Epidemiological findings show that childhood obesity is rapidly rising in Western society, as well as in developing countries. This pandemic is not without consequences and can affect the risk of future cardiovascular disease in these children. Childhood obesity is associated with endothelial dysfunction, the first yet still reversible step towards atherosclerosis. Advanced research techniques have added further insight on how childhood obesity and associated comorbidities lead to endothelial dysfunction. Techniques used to measure endothelial function were further brought to perfection, and novel biomarkers, including endothelial progenitor cells, were discovered. The aim of this paper is to provide a critical overview on both in vivo as well as in vitro markers for endothelial integrity. Additionally, an in-depth description of the mechanisms that disrupt the delicate balance between endothelial damage and repair will be given. Finally, the effects of lifestyle interventions and pharmacotherapy on endothelial dysfunction will be reviewed.

Variação do diâmetro da artéria braquial em crianças obesas: presente e futuro

OBJETIVO: Revisão da literatura acerca do uso da medida da variação do diâmetro da artéria braquial por ultrassonografia de alta resolução (dilatação mediada por fluxo) como preditor de risco para doença cardiovascular em crianças e adolescentes obesos. FONTES DE DADOS: Levantamento de publicações indexadas no Medline/PubMed de trabalhos publicados entre 2002 e 2011, rastreadas com a combinação dos descritores: "endothelium", "child", "ultrasonography" e "obesity", além de estudos e textos clássicos sobre o tema. Foram encontradas 54 publicações e 32 delas foram incluídas na presente revisão do tema. SINTESE DOS DADOS: O estudo da disfunção endotelial tem sido empregado como preditor de risco para doenças cardiovasculares, tais como aterosclerose e doença cardíaca coronariana, visto que a lesão endotelial é um importante evento na fisiopatologia de tais doenças. CONCLUSÕES: A dilatação mediada por fluxo da artéria braquial mostra-se importante como ferramenta diagnóstica e prognóstica na avaliação da função endotelial de crianças e adolescentes com excesso de peso por ser um método não invasivo, com boa aplicabilidade quanto ao custo, à inocuidade e ao benefício.

Adolescents with congenital adrenal hyperplasia because of 21-hydroxylase deficiency have vascular dysfunction

CONTEXT

Patients with congenital adrenal hyperplasia (CAH) because of 21-hydroxylase deficiency have multiple vascular risk factors. Young adults with CAH have increased intima media thickness, but there have been no studies of vascular function and structure in children with CAH.

OBJECTIVE

To establish whether children with CAH have reduced vascular function and increased carotid intima media thickness (cIMT) when compared to healthy and obese children.

DESIGN AND PATIENTS

Cross-sectional study of 14 patients (14.8 years ± 3.2, seven boys) with CAH secondary to 21-hydroxylase deficiency compared to 28 obese and 53 healthy controls.

MEASUREMENTS

All subjects had assessment of endothelial function flow-mediated dilatation, (FMD), smooth muscle function glyceryl tri-nitrate dilatation (GTN) and cIMT. Anthropometric data, resting blood pressure and biochemical variables were also measured.

RESULTS

Congenital adrenal hyperplasia subjects had significantly reduced FMD (4.5 ± 3.0% vs 7.5 ± 5.2%; P = 0.04) and GTN (17.2 ± 1.6% vs 28.4 ± 8.4%; P < 0.001) when compared to controls and the impairment was comparable to the obese cohort. There was no significant difference in cIMT between groups. CAH subjects had increased homoeostasis model of assessment-insulin resistance [HOMA-IR 2.5 (0.2-2.9) vs 1.8 (0.5-4.2); P = 0.04], waist-to-height ratio (0.47 ± 0.05 vs 0.44 ± 0.04; P = 0.02) and higher systolic blood pressure Z score (0.29 ± 0.9 vs-0.24 ± 0.64, P = 0.01) compared to healthy controls but not when compared to obese controls.

CONCLUSIONS

Subjects with CAH have evidence of vascular dysfunction by adolescence.

Hypoglycemia, but not glucose variability, relates to vascular function in children with type 1 diabetes

BACKGROUND

Chronic sustained hyperglycemia unequivocally predicts vascular disease in diabetes. However, the vascular risk of glucose variability, including hypoglycemia, is uncertain. Vascular dysfunction is present in children with type 1 diabetes and is a critical precursor of atherosclerosis. We aimed to evaluate the relationship between glucose variability and vascular function in children with type 1 diabetes.

SUBJECTS AND METHODS

Fifty-two type 1 diabetes subjects (14 [SD 2.7] years old, 25 males) had continuous glucose monitoring that included 48 h of data used to evaluate glucose variability (mean amplitude of glycemic excursions [MAGE] and other measurements) and hypoglycemia indices (glycemic risk assessment diabetes equation [GRADE] hypoglycemia, Low Blood Glucose Index [LBGI], and observed duration of hypoglycemia). Children with type 1 diabetes and 50 age- and gender-matched controls had assessments of vascular function (flow-mediated dilatation [FMD] and glyceryl trinitrate-mediated dilatation [GTN]).

RESULTS

Children with type 1 diabetes had lower FMD and GTN than controls (P=0.02 and P<0.001, respectively). GRADE hypoglycemia and LBGI were inversely related to FMD (r=-0.36, P=0.009 and r=-0.302, P=0.03, respectively) but did not relate to GTN. GRADE hypoglycemia was independently related to FMD (regression coefficient=-0.25±0.09, P=0.006). MAGE and other measurements of glucose variability measurements did not relate to FMD or GTN.

CONCLUSIONS

Hypoglycemia, but not glucose variability, during continuous glucose monitoring relates to impaired vascular endothelial function in children with type 1 diabetes. Hypoglycemia may be an additional risk factor for early cardiovascular disease, but the effect of glucose variability, independent of glycosylated hemoglobin, on vascular function remains uncertain.

Endothelial dysfunction, inflammation, and oxidative stress in obese children and adolescents: markers and effect of lifestyle intervention

With an increasing prevalence, pediatric obesity is often a prelude to adulthood obesity, and represents a major public health issue. Comorbidities are very common and severe in obese adults, justifying the search for earlier markers or risk factors for cardiovascular diseases in obese children. Endothelial dysfunction has been found to be present in the early stages of atherosclerosis, and can be non-invasively assessed with widely accepted and well-standardized techniques at the macrocirculation level. Endothelial dysfunction at the microcirculation level is less documented in obese children. Obesity in children has been repeatedly and independently correlated to endothelial dysfunction, inflammation and oxidative stress markers, although the relationship between these factors remains to be investigated. However, this would not only allow substantial improvements in risk stratification, but also provide essential data regarding the evolution of endothelial dysfunction in childhood obesity, especially during puberty when pro-inflammatory and pro-oxidative changes, with relative insulin resistance, occur. Therapeutic strategies such as lifestyle interventions in early childhood obesity appear all the more necessary, optimally including both exercise and diet because of their known effects on inflammatory and oxidative stress markers, potentially reversing endothelial dysfunction.

Cardiovascular disease risk in young people with type 1 diabetes

Cardiovascular disease (CVD) is the most frequent cause of death in people with type 1 diabetes (T1D), despite modern advances in glycemic control and CVD risk factor modification. CVD risk identification is essential in this high-risk population, yet remains poorly understood. This review discusses the risk factors for CVD in young people with T1D, including hyperglycemia, traditional CVD risk factors (dyslipidemia, smoking, physical activity, hypertension), as well as novel risk factors such as insulin resistance, inflammation, and hypoglycemia. We present evidence that adverse changes in cardiovascular function, arterial compliance, and atherosclerosis are present even during adolescence in people with T1D, highlighting the need for earlier intervention. The methods for investigating cardiovascular risk are discussed and reviewed. Finally, we discuss the observational studies and clinical trials which have thus far attempted to elucidate the best targets for early intervention in order to reduce the burden of CVD in people with T1D.

Endothelial function in pre-pubertal children at risk of developing cardiomyopathy: a new frontier

Although it is known that obesity, diabetes, and Kawasaki's disease play important roles in systemic inflammation and in the development of both endothelial dysfunction and cardiomyopathy, there is a lack of data regarding the endothelial function of pre-pubertal children suffering from cardiomyopathy. In this study, we performed a systematic review of the literature on pre-pubertal children at risk of developing cardiomyopathy to assess the endothelial function of pre-pubertal children at risk of developing cardiomyopathy. We searched the published literature indexed in PubMed, Bireme and SciELO using the keywords 'endothelial', 'children', 'pediatric' and 'infant' and then compiled a systematic review. The end points were age, the pubertal stage, sex differences, the method used for the endothelial evaluation and the endothelial values themselves. No studies on children with cardiomyopathy were found. Only 11 papers were selected for our complete analysis, where these included reports on the flow-mediated percentage dilatation, the values of which were 9.80±1.80, 5.90±1.29, 4.50±0.70, and 7.10±1.27 for healthy, obese, diabetic and pre-pubertal children with Kawasaki's disease, respectively. There was no significant difference in the dilatation, independent of the endothelium, either among the groups or between the genders for both of the measurements in children; similar results have been found in adolescents and adults. The endothelial function in cardiomyopathic children remains unclear because of the lack of data; nevertheless, the known dysfunctions in children with obesity, type 1 diabetes and Kawasaki's disease may influence the severity of the cardiovascular symptoms, the prognosis, and the mortality rate. The results of this study encourage future research into the consequences of endothelial dysfunction in pre-pubertal children.

Breastfeeding duration, age of starting solids and high BMI risk and adiposity in Indian children

This study utilized data from a prospective birth cohort study on 568 Indian children, to determine whether a longer duration of breastfeeding and later introduction of solid feeding were associated with a reduced higher body mass index (BMI) and less adiposity. Main outcomes were high BMI (>90th within-cohort sex-specific BMI percentile) and sum of skinfold thickness (triceps and subscapular) at age 5. Main exposures were breastfeeding (six categories from 1-4 to ≥21 months) and age of starting regular solid feeding (four categories from ≤3 to ≥6 months). Data on infant-feeding practices, socio-economic and maternal factors were collected by questionnaire. Birthweight, maternal and child anthropometry were measured. Multiple regression analysis that accounted for potential confounders demonstrated a small magnitude of effect for breastfeeding duration or introduction of solid feeds on the risk of high BMI but not for lower skinfold thickness. Breastfeeding duration was strongly negatively associated with weight gain (0-2 years) [adjusted β = -0.12 standard deviation, 95% confidence interval (CI): -0.19 to -0.05 per category change in breastfeeding duration, P = 0.001], and weight gain (0-2 years) was strongly associated with high BMI at 5 years (adjusted odds ratio = 3.8, 95% CI: 2.53-5.56, P < 0.001). In our sample, findings suggest that longer breastfeeding duration and later introduction of solids has a small reduction on later high BMI risk and a negligible effect on skinfold thickness. However, accounting for sampling variability, these findings cannot exclude the possibility of no effect at the population level.

Flow-mediated dilatation of the brachial artery is a poorly reproducible indicator of microvascular function in Type I diabetes mellitus

BACKGROUND

Flow-mediated dilatation (FMD) of the brachial artery is commonly measured as a surrogate marker of endothelial function. Its measurement is, however, technically demanding and reports regarding its reproducibility have not always been favourable.

AIM

Two Type I diabetes and control group comparator studies were conducted to assess the reproducibility of FMD and to analyse blood flow data normally discarded during FMD measurement.

DESIGN

The studies were sequential and differed only with regard to operator and ultrasound machine. Seventy-two subjects with diabetes and 71 controls were studied in total.

METHODS

Subjects had FMD measured conventionally. Blood velocity waveforms were averaged over 10 pulses post forearm ischaemia and their component frequencies analysed using the wavelet transform, a mathematical tool for waveform analysis. The component frequencies were grouped into 11 bands to facilitate analysis.

RESULTS

Subjects were well-matched between studies. In Study 1, FMD was significantly impaired in subjects with Type I diabetes vs. controls (median 4.35%, interquartile range 3.10-4.80 vs. 6.50, 4.79-9.42, P < 0.001). No differences were detected between groups in Study 2, however. However, analysis of blood velocity waveforms yielded significant differences between groups in two frequency bands in each study.

CONCLUSION

This report highlights concerns over the reproducibility of FMD measures. Further work is required to fully elucidate the role of analysing velocity waveforms after forearm ischaemia.

New forecasting methodology indicates more disease and earlier mortality ahead for today's younger Americans

Traditional methods of projecting population health statistics, such as estimating future death rates, can give inaccurate results and lead to inferior or even poor policy decisions. A new "three-dimensional" method of forecasting vital health statistics is more accurate because it takes into account the delayed effects of the health risks being accumulated by today's younger generations. Applying this forecasting technique to the US obesity epidemic suggests that future death rates and health care expenditures could be far worse than currently anticipated. We suggest that public policy makers adopt this more robust forecasting tool and redouble efforts to develop and implement effective obesity-related prevention programs and interventions.

Impaired flow-mediated dilatation response in uncomplicated Type 1 diabetes mellitus: influence of shear stress and microvascular reactivity

Impaired FMD (flow-mediated dilatation) has traditionally been recognized as an indirect marker of NO bioactivity, occurring in disease states such as DM (diabetes mellitus). Endothelium-dependent FMD is a homoeostatic response to short-term increases in local shear stress. Microvascular dysfunction in DM influences blood flow velocity patterns. We explored the determinants of the FMD response in relation to evoked DSS (diastolic shear stress) and forearm microcirculation haemodynamics by quantifying changes in Doppler flow velocity waveforms between groups. Forty patients with uncomplicated Type 1 DM and 32 controls underwent B-mode and Doppler ultrasound scanning to interrogate the brachial artery. Postischaemic Doppler velocity spectral envelopes were recorded and a wavelet-based time-frequency spectral analysis method was employed to track change in distal microcirculatory haemodynamics. No difference in baseline brachial artery diameter was evident between the groups (4.15 compared with 3.94 mm, P=0.23). FMD was significantly impaired in patients with Type 1 DM (3.95 compared with 7.75%, P<0.001). Endothelium-independent dilatation in response to GTN (glyceryl trinitrate) was also significantly impaired (12.07 compared with 18.77%, P<0.001). DSS (dyn/cm2) was significantly reduced in the patient group (mean 20.19 compared with 29.5, P=0.001). Wavelet interrogation of postischaemic flow velocity waveforms identified significant differences between groups. In conclusion, DSS, microcirculatory function and endothelium-independent vasodilatation in response to GTN are important determinants that impact on the magnitude of FMD response and are impaired in patients with Type 1 DM. Impaired FMD response is multifactorial in origin and cannot be attributed solely to a diminished NO bioavailability.

Severe obesity is associated with impaired arterial smooth muscle function in young adults

The degree of arterial dilatation induced by exogenous nitrates (nitrate-mediated dilatation, NMD) has been similar in obese and normal-weight adults after single high-dose glyceryl trinitrate (GTN). We examined whether NMD is impaired in obesity by performing a GTN dose-response study, as this is a potentially more sensitive measure of arterial smooth muscle function. In this cross-sectional study, subjects were 19 obese (age 31.0 ± 1.2 years, 10 male, BMI 44.1 ± 2.1) and 19 age- and sex-matched normal-weight (BMI 22.4 ± 0.4) young adults. Blood pressure (BP), triglycerides, high-density lipoprotein (HDL), and low-density lipoprotein (LDL)-cholesterol, glucose, insulin, high-sensitivity C-reactive protein (hs-CRP), carotid intima-media thickness (CIMT), and flow-mediated dilatation (FMD) were measured. After incremental doses of GTN, brachial artery maximal percent dilatation (maximal NMD) and the area under the dose-response curve (NMD AUC) were calculated. Maximal NMD (13.4 ± 0.9% vs. 18.3 ± 1.1%, P = 0.002) and NMD AUC (54,316 ± 362 vs. 55,613 ± 375, P = 0.018) were lower in obese subjects. The obese had significantly higher hs-CRP, insulin, and CIMT and lower HDL-cholesterol. Significant bivariate associations existed between maximal NMD or NMD AUC and BMI-group (r = -0.492, P = 0.001 or r = -0.383, P = 0.009), hs-CRP (r = -0.419, P = 0.004 or r = -0.351, P = 0.015), and HDL-cholesterol (r = 0.374, P = 0.01 or r = 0.270, P = 0.05). On multivariate analysis, higher BMI-group remained as the only significant determinant of maximal NMD (r² = 0.242, β = -0.492, P = 0.002) and NMD AUC (r² = 0.147, β = -0.383, P = 0.023). In conclusion, arterial smooth muscle function is significantly impaired in the obese. This may be important in their increased cardiovascular risk.

Elevated body mass index in Texas Head Start children: a result of heredity and economics

OBJECTIVE

The problem of high body mass index (BMI) for age in the Head Start population in Texas is of great concern. The primarily Mexican American population is at high risk for diabetes and cardiovascular disease. This study examines the prevalence of elevated BMI for age in the Head Start population in a sampling of South Texas border counties and a Central Texas county from 2003-2008, and compares it to the Centers for Disease Control and Prevention (CDC) and National Health and Nutrition Examination Survey (NHANES) data for Hispanic preschool children.

METHODS

18,462 age/gender-adjusted BMI measurements obtained by Texas Head Start centers for 2-5 year old children were analyzed to determine the prevalence of BMI for age at the 97th, 95th, and 85th percentiles.

RESULTS

In the overall Texas population, 40.79% of males and 36.73% of females were overweight (85th percentile and above) and 20.01% of the males and 19.04% of the females were obese (95th percentile and above). The prevalence of high BMI for age was stable between 2003-2008; however, the overweight cohort increased with the age of the children over that period of time.

CONCLUSION

The observed prevalence of elevated BMI in the Texas population is significantly higher than the results for the 2000 age-adjusted gender specific CDC growth charts for Mexican-American children ages 2-5 years old in the NHANES data for 2003-2006. The Texas-Mexico border counties had the highest prevalence of elevated BMI, demonstrating a critical need for dietary and exercise interventions in this medically underserved area.

Insulin resistance and its association with the components of the metabolic syndrome among obese children and adolescents

Background

Insulin resistance is the primary metabolic disorder associated with obesity; yet little is known about its role as a determinant of the metabolic syndrome in obese children. The aim of this study is to assess the association between the degree of insulin resistance and the different components of the metabolic syndrome among obese children and adolescents.

Methods

An analytical, cross-sectional and population-based study was performed in forty-four public primary schools in Campeche City, Mexico. A total of 466 obese children and adolescents between 11-13 years of age were recruited. Fasting glucose and insulin concentrations, high density lipoprotein cholesterol, triglycerides, waist circumference, systolic and diastolic blood pressures were measured; insulin resistance and metabolic syndrome were also evaluated.

Results

Out of the total population studied, 69% presented low values of high density lipoprotein cholesterol, 49% suffered from abdominal obesity, 29% had hypertriglyceridemia, 8% presented high systolic and 13% high diastolic blood pressure, 4% showed impaired fasting glucose, 51% presented insulin resistance and 20% metabolic syndrome. In spite of being obese, 13% of the investigated population did not present any metabolic disorder. For each one of the components of the metabolic syndrome, when insulin resistance increased so did odds ratios as cardiometabolic risk factors.

Conclusions

Regardless of age and gender an increased degree of insulin resistance is associated with a higher prevalence of disorders in each of the components of the metabolic syndrome and with a heightened risk of suffering metabolic syndrome among obese children and adolescents.

Arterial distensibility is reduced in overweight pre- and early pubescent children

The objective of this study was to examine the differences in arterial distensibility between overweight/obese and normal weight pre- and early pubescent boys and girls. Arterial distensibility was measured in 65 children (43 normal weight and 22 overweight/obese) between the ages of 9 and 12 years. Weight classification was based on age and sex-specific body mass index (BMI) cut-offs and pubertal maturation by Tanner staging. Distensibility was determined using B-Mode echo-Doppler ultrasound to measure changes in the right common carotid artery (CCA) diameter, while carotid pulse pressure was measured at the left CCA by applanation tonometry. Accounting for age and sex (ANCOVA), CCA distensibility showed a significant difference (P < 0.05) between normal weight (0.79 +/- 0.21) and overweight children (0.61 +/- 0.21 mmHg(-1) x 10(-2)). Univariate analysis revealed that CCA distensibility was related to BMI, systolic blood pressure, brachial pulse pressure, and relative oxygen uptake (VO(2peak), milliliter per kilogram per minute). Multivariate analysis revealed that, when adjusting for brachial pulse pressure and relative VO(2peak), differences in CCA distensibility by BMI were no longer significant. This study demonstrates that attenuated arterial distensibility exists in overweight pre- and early pubescent children. As well, this study highlights the influential role of blood pressure and aerobic fitness on arterial distensibility.

The relationship between cortisol concentrations in pregnancy and systemic vascular resistance in childhood

OBJECTIVE

To assess the relationship between cortisol concentrations in the last trimester of pregnancy and systemic vascular resistance - SVR in childhood.

MATERIALS AND METHODS

This study is part of a cohort involving 130 Brazilian pregnant women and their children, ages 5 to 7years. Maternal cortisol was determined in saliva by an enzyme immunoassay utilizing the mean concentration of 9 samples of saliva (3 in each different day), collected at the same time, early in the morning. SVR was assessed by the HDI/PulseWave CR-2000 Cardiovascular Profiling System(R). Socioeconomic and demographic characteristics and life style factors were determined by a questionnaire. The nutritional status of the women and children was assessed by the body mass index - BMI. The association between maternal cortisol and SVR in childhood was calculated by multivariate linear regression analysis.

RESULTS

There were statistically significant associations between maternal cortisol and SVR (p=0.043) and BMI-z score of the children (p=0.027), controlling for maternal BMI, birth weight, age, and gender of the children.

CONCLUSION

As far as we know this is the first study in the literature assessing the association between cortisol concentrations in pregnancy and SVR in childhood. Overall, the data suggest that exposure to excess glucocorticoid in the prenatal period is associated to vascular complications in childhood, predisposing to cardiovascular diseases in later life.