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

Ambulatory blood pressure monitoring in children and adolescents post-hematopoietic stem cell transplantation

BACKGROUND

One of the long-term complications after hematopoietic stem cell transplantation (HSCT) is hypertension (HT). Previous studies showed that 10-15% of children post-HSCT had office HT, but only a few studies used ambulatory blood pressure monitoring (ABPM). The present study was aimed at exploring the frequency and factors associated with ABPM HT in children post-HSCT.

METHODS

Patients aged ≥ 6 years who survived ≥ 2 years after HSCT were enrolled. Clinical and ABPM data were reviewed. ABPM HT was defined according to the 2022 American Heart Association guidelines. Factors associated with HT were analyzed by logistic regression.

RESULTS

Ninety-eight (60 males) patients with a mean age of 15.1 years and a median follow-up time at 4.5 years after HSCT were included. Fifteen patients (15.3%) had ABPM HT (2 ambulatory HT and 13 masked HT). The ABPM HT group had a significantly older age (19 vs. 14 years), a higher proportion of males (87% vs. 57%), a higher office systolic BP index (0.93 vs. 0.85), a higher office diastolic BP index (0.96 vs. 0.82) and a higher proportion of current use of prednisolone and tacrolimus than those in the normal ABPM group. Multivariate analysis revealed that office diastolic BP index was associated with ABPM HT. Left ventricular mass index was significantly correlated with ABPM but not with office BP parameters.

CONCLUSIONS

HT in children post-HSCT was not uncommon and most could not be detected with office BP measurement. A diastolic BP index can be used as a screening tool for HT. A higher resolution version of the Graphical abstract is available as Supplementary information.

Childhood obesity and hypertension in pregnancy: a two-sample Mendelian randomization analysis

BACKGROUND

The causal relationship between childhood obesity and hypertension in pregnancy remains unclear. To examine the causal association between childhood obesity and hypertension in pregnancy, two-sample Mendelian randomization analysis was applied.

METHODS

Single-nucleotide polymorphisms (SNPs) associated with childhood obesity were obtained from a published genome-wide association study (GWAS) of 13 848 European individuals. Summary-level data for hypertension in pregnancy were obtained from the FinnGen consortium (11534 cases and 162212 controls). Inverse-variance weighted analysis, weighted-median analysis, and Mendelian randomization-Egger regression were conducted in this Mendelian randomization analysis. Sensitivity analyses were conducted to confirm the accuracy and robustness of our results.

RESULTS

Genetically determined childhood obesity significantly affects hypertension in pregnancy by IVW [odds ratio (OR) = 1.161, 95% confidence interval (CI) 1.086-1.039; P = 9.92 × 10 -6 ] and weighted median (OR = 1.123, 95% CI 1.038-1.214; P  = 0.004). These results were validated by multiple sensitivity analyses.

CONCLUSION

A causal effect between genetically predicted childhood obesity and the risk of hypertension in pregnancy was identified. The prevention of hypertension in pregnancy should be promoted in populations with childhood obesity.

Evaluation of coronary microvascular dysfunction and risk factors in children and youth with Turner syndrome by magnetic resonance myocardial perfusion imaging

OBJECTIVE

Turner syndrome (TS) has an increased predisposition to ischaemic heart disease and the status of coronary microcirculation in TS is largely unknown. This study aims to evaluate myocardial microvascular function in TS using first-pass magnetic resonance perfusion imaging and determine significant risk factors contributing to microvascular dysfunction in the early stage.

DESIGN

Perspective cohort study.

PATIENTS

The study cohort consisted of 67 children and youth with TS and 32 age- and gender-matched controls. Measurements Clinical characteristics, left ventricle (LV) volume and function and cardiovascular magnetic resonance-derived myocardial perfusion parameters were assessed. Univariable and multivariable linear regression analyses were performed to assess the potential risk factors for microvascular dysfunction.

RESULT

Microvascular perfusion decreased in TS in global and segmented myocardium as reflected in the lower upslope_cor and maximum signal intensity (MaxSI) of LV myocardium compared to controls. Multivariable linear regression analysis indicated that age (β = -0.107, 95% confidence interval [CI] = -0.201 to -0.013, p = .026) and being overweight/obese (β = -1.155, CI = -2.134 to -0.176, p = .021) were independent impact factors of microvascular dysfunction. Subgroup analysis showed the upslope_cor of older patients with TS decreased more significantly compared with that of normal controls. Upslope_cor and MaxSI were lower in overweight/obese patients with TS than in patients with normal body mass index (BMI) and controls.

CONCLUSION

Myocardial microvascular dysfunction can occur in children and youth patients with TS. Age and overweight/obesity were the independent risk factors of microvascular dysfunction, which imply the importance of lowering BMI for the prevention of coronary heart disease in young TS population.

Cross-Sectional Association Between Body Fat Composition and Biomarkers of Inflammation and Endothelial Dysfunction in Children with Overweight/Obesity

BACKGROUND

Childhood obesity is most prevalent nutritional disorder worldwide. Studies on clinical correlations between body fat (BF) composition, lipid profile, inflammatory biomarkers, and endothelial dysfunction (ED) parameters in children from United Arab Emirates (UAE) are limited. Therefore, we aimed to study obesity pattern in children and determine clinical correlations with biomarkers.

METHODS

Children (6-13 years) from different schools were divided into obese, overweight, and normal groups based upon Centers for Disease Control and Prevention weight-for-age centiles study (n=166). Anthropometric, BF composition, lipid profile, inflammatory, and ED biomarkers were determined and analyzed using SPSS software.

RESULTS

The mean age and weight ± SD of participants were 10.6 ± 2.6 years and 48.2 ± 19.5 kg with 65% as overweight or obese. In normal, overweight, and obese group male were 40 (70.2%), 35 (67.3%), and 40 (70.2%) and female were 17 (29.8%), 17 (32.7%) and 17 (29.8%). There was significant difference in age (p<0.01), height (p< 0.01), weight (p< 0.01) among groups. Obesity markers (MCP-1, leptin, adiponectin) showed positive correlation with age, height, weight, WC, BF%, body fat mass (BFM), body muscle mass (BMM). A significant correlation (all p<0.01) of BMM with SBP (r=0.412), DBP (r=0.255), MCP-1 (r=0.558), adiponectin (r=0.635), hs-CRP (r=0.263), IL-6 (r=0.348), TNF-alpha (r=0.370), ICAM-1 (r=0.237), and VCAM-1 (r=0.343). The inflammatory markers (ICAM-1, VCAM-1) showed significant correlations with age, height, weight, WC, BF%, BFM, BMM. Leptin significantly (all p<0.01) correlated with age (r=0.470), height (r=0.423), weight (r=0.677), WC (r=0.606), BF (r=0.700), BFM (r=0.752), and BMM (r=0.524) and negatively correlated with TBW (r=-0.701). Adiponectin also showed a significant (all p<0.01) positive correlation with age, height, weight, WC, BF, BFM, and BMM.

CONCLUSION

A strong association between BF composition, lipid profile, and inflammatory and ED biomarkers was observed in the study. Thus, immediate measures should be implemented to reduce risk of obesity and associated diseases.

Vitamin D Supplementation in the Assessment of Cardiovascular Risk Factors in Overweight and Obese Children

Background: Childhood obesity is associated with cardiovascular-disease (CVD) risk factors, an unfavorable lipid profile and reduced levels of 25(OH)D. The aim of our study is to evaluate whether vitamin D supplementation may play a role in the assessment of the CVD risk factors in overweight/obese children and adolescents. Methods: We performed a retrospective observational study involving children (9−15 years of age) with a known diagnosis of overweight or obesity (BMI > 25) and decreased levels of 25(OH)D (<25 ng/mL), who underwent oral vitamin D supplementation (100,000 UI, one vial/month) for six months. The anthropometric parameters, 25(OH)D, serum lipids and ALT levels were measured at the beginning (T0) and after 6 months (T1). Results: Of the 58 patients recruited, 45 had an increase in the serum 25(OH)D levels after supplementation. Vitamin D supplementation was associated with a decrease in the serum levels of the total cholesterol (p = 0.009), LDL-C (p = 0.005) and ALT (p = 0.005), and an increase in HDL-C (p = 0.03). These results were confirmed when the correction for the body mass index (BMI) was applied. Conclusions: The favorable effect of vitamin D supplementation on the total cholesterol, LDL-C, HDL-C and ALT could transform these values into modifiable risk factors starting in early childhood, with beneficial effects on long-term health.

Serum Chemerin and Apelin Levels in Obese Children: Relation to Endothelial Function and Inflammation from a Cross-sectional Case–Control Study

BACKGROUND: Childhood obesity is a global threat with subsequent health problems among which and most important is cardiovascular problems. It is now claimed that adipokines secreted by adipose tissue are responsible for such consequences. Newly discovered adipokines chemerin and apelin are under investigation for their link with obesity related co-morbidites. AIM: The aim of the present study was to assess the serum levels of chemerin and apelin in obese children and to explore the correlation between these two biomarkers and the inflammatory as well as the endothelial cell activation markers PATIENTS AND METHODS: This study was a cross-sectional case control study that comprised 45 pre-pubertal obese children aged (6– < 12) years old of both sexes (22 males and 23 females), in addition to 45 matched age and sex lean children serving as controls (21 males and 24 females). Serum levels of chemerin, apelin, ICAM-1, E-selectin and hs-CRP were measured for obese and controls. RESULTS: Obese children showed higher levels of chemerin, apelin, ICAM-1 and E-selectin than controls. Chemerin and apelin showed significant correlations with all parameters except for age. Anthropometric parameters with hs-CRP revealed significant correlation even after adjustment for age and sex while apelin only showed a significant correlation with age. Multiple regression analyses with hs -CR , E-selectin and ICAM-1 as dependent variables and BMI Z score ,age, sex, chemerin and apelin as independent variables showed the effect of chemerin and apelin on  the increased  levels of hs -CR , E-selectin and ICAM-1 . CONCLUSION: Elevated levels of chemerin and apelin may serve as indices of ongoing obesity-related disorders in obese children.

Multiple non-invasive peripheral vascular function parameters with obesity and cardiometabolic risk indicators in school-aged children

Background

The Peripheral Arterial Tonometry (PAT) technique measured by Endo-PAT™, is recently introduced for peripheral vascular assessment in youth, primarily benefits from its easy and non-invasive operation. However, the value of Endo-PAT as early indicator of obesity-related cardiometabolic risk factors remains unclear, with few studies focusing solely on Reactive Hyperemia Index (RHI). A wider coverage of Endo-PAT algorithms is recommended to be applied simultaneously in youth. We evaluated the value of multiple Endo-PAT parameters on obesity and cardiometabolic risk indication in school-aged children, in comparison with another non-invasive Brachial-ankle Pulse Wave Velocity (BaPWV) method.

Methods

This cross-sectional sample included 545 youth (80 with overweight and 73 with obesity) aged 7–17 years. RHI, Framingham-Reactive Hyperemia Index (F-RHI), peak response and Augmentation Index normalized to Heart Rate 75 bpm (AIx75) were measured by Endo-PAT™ 2000 device. Spearman correlations of abovementioned Endo-PAT parameters and BaPWV, with adiposity (weight, waist circumference, BMI, body fat mass) and cardiometabolic indicators (glycemic response, blood pressure, lipid profiles) were calculated with non-linear adjustment on age, height, gender and baseline pulse-wave amplitude (PWA) using fractional polynomials. Analysis was repeated in students with obesity only [median BMI z score: 3.0 (2.5,3.5)] for sensitivity analysis.

Results

The correlations of Endo-PAT parameters with adiposity measures and cardiometabolic indicators were overall mixed and weak (DBP: r ranged from − 0.20 to − 0.13, others: |r| < 0.1) after adjustment. Except that body fat mass (AIx75: r = 0.52 p < 0.01) and triglyceride level (RHI: r = − 0.32 p < 0.01, F-RHI: r = − 0.21 p > 0.05) was moderately reversed in students with obesity. In contrast, BaPWV showed consistently moderate correlations (|r| ranged from 0.123 to 0.322, p < 0.05) with almost all adiposity measures and cardiometabolic indicators regardless of obesity status.

Conclusion

Contrary to previous suggestion, various Endo-PAT parameters performed similarly weak for early cardiometabolic risk indication in school-aged children, and less preferable than that by another non-invasive BaPWV method. Despite further investigation is needed to improve certainty of relevant research evidence, innovative technology and algorithms taking into account specifics of young population are worthy of consideration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03214-4.

Supportive treatment of vascular dysfunction in pediatric subjects with obesity: the OBELIX study

INTRODUCTION

Overweight or obese children develop abnormal endothelial cell dysfunction and arterial intima-media thickening with increased vasomotor tone and inflammation. Curcumin, resveratrol, zinc, magnesium, selenium, and vitamin D have shown beneficial effects on endothelial function. We test, among overweight and obese pediatric subjects, the effects on the endothelium of a combination of curcumin, resveratrol, zinc, magnesium, selenium, and vitamin D.

METHODS

Forty-eight subjects (6-17 years) were randomized into two groups (placebo vs treatment) attended three visits at 0, 3, and 6 months (±15 days). Endothelial function was assessed by means of a post-occlusive release hyperemic (PORH) test for estimation of delta flow (DF) and hyperemic AUC index, and a heat provocation test (HPT) to measure DF HPT (DF_HPT).

RESULTS

Significant DF difference was noted at 6 months in both groups (p < 0.001). Overall time trend was significantly different between baseline, 3 months, and 6 months both in placebo (p < 0.05) and treatment (p < 0.001) groups and their comparison (p < 0.001). No differences were noted in hyperemic AUC index (3 and 6 months), whilst there were significant differences in time trends of rreatment (p < 0.001) and placebo (p < 0.05) groups and their comparison (p < 0.001). DF_HPT difference between groups was significant at 3 and 6 months (p < 0.05). The overall time trend was significant exclusively in Treatment group between 3 and 6 months (p < 0.05). Correlation with anthropometrics was found for DF and body mass index (r = 0.677 6 months, p < 0.05), as well as for hyperemic AUC index and males (r = 0.348, p < 0.05), while DF_HPT showed no correlation.

CONCLUSION

Curcumin, resveratrol, zinc, magnesium, selenium, and vitamin D appear to be promising in enhancing endothelial function by improvement of both DF in the PORH test and DF in the HPT, lowering the risk of developing cardiovascular diseases in overweight and obese pediatric subjects.

Comparison of Carotid Intima-Media Thickness in Children and Adults With and Without Obesity: A Hysteresis Model

OBJECTIVE

To describe a third-degree polynomial function (hysteresis) of the effect size of age, obesity, and insulin sensitivity over the carotid intima-media thickness (c-IMT), in the pediatric and adult groups.

METHODS

A quasi-experimental study with fixed factor analysis of age (children aged 8-12 years, n = 73; adults aged 21-45 years, n = 82) and obesity (yes, n = 76; no, n = 79) was conducted to analyze the effect on the c-IMT and Matsuda insulin sensitivity index values. This quasi-experimental design was analyzed with robust regression modeling.

RESULTS

The additive effect of obesity, independent of age, was evident in the case of the c-IMT values. There was no interaction effect, but a significant difference between participants with normal weight and those with obesity was found (P < .0001). The difference between adults and children was also significant, but the effect size was smaller. A model was created based on age, Tanner stage, and obesity using the c-IMT and Matsuda insulin sensitivity index values. A linear function fit as R², and the cubic function estimated parameters like a polynomial model.

CONCLUSION

This practical study design showed that children with obesity displayed the same levels of carotid intima-media abnormalities as adults with obesity. The polynomial shape of the model suggests potentially poor outcomes that resemble the hysteresis process and may predict chronic cardiometabolic events during early adulthood.

The effect of weight regain on cardiometabolic health in children with obesity: A systematic review of clinical studies

AIMS

Children with obesity are treated by a lifestyle intervention to obtain weight loss. Nevertheless, weight regain often occurs. This systematic review examines the effect of weight regain on cardiometabolic health and summarizes these results in the metabolic syndrome prevalence as integrated endpoint.

DATA SYNTHESIS

A literature search was performed in PubMed and Web of Science. Studies were selected if they included participants aged <18 years with obesity and presented data before and after weight loss and after weight regain hereby reporting minimally 1 cardiovascular risk factor at every assessment. After screening, nine articles remained. Generally, the diastolic BP re-increased after weight regain, whereas for systolic BP a sustained result for 6 months was reported with an increase during longer follow-up. No significant changes in fasting glucose were reported after weight regain compared to baseline. Regarding triglycerides, a complete weight regain re-increased the lowered values to baseline, whereas a partial regain resulted in a sustained decrease in triglycerides in 2 studies and an increase to intermediate levels in 1 paper. HDL-cholesterol only rose several months after initiating treatment. Hs-CRP remained lowered for a longer period than the moment where the weight loss nadir was achieved.

CONCLUSION

Research on weight regain and cardiometabolic health in children with obesity is scarce. No convincing evidence was found for a worsening of the cardiometabolic profile after weight regain. Some benefits even persisted despite weight recovery. Subsequently, the metabolic syndrome prevalence seems temporarily lowered after weight loss, despite weight regain.

Predictive Markers of Early Cardiovascular Impairment and Insulin Resistance in Obese Pediatric Patients

BACKGROUND

The increased prevalence of obesity among children determined the rising number of its comorbidities in children and adults, too. This study aimed to evaluate certain markers of inflammation and insulin resistance in obese pediatric patients, identifying those who are more likely to develop further complications.

METHODS

We included 115 obese pediatric patients: 85 overweight and obese patients in the study group and 30 normal-weight patients in the control group. We calculated the body mass index (BMI) and we evaluated markers (biological, inflammatory) and the hormones profile.

RESULTS

Low-threshold inflammation was assessed by measuring interleukin 6 IL-6 and Intercellular Adhesion Molecules (ICAM). The analysis showed that IL-6 is significantly correlated with glucose (p = 0.001) and BMI value (p = 0.031). ICAM correlates significantly with triglycerides (p = 0.001), glucose (p = 0.044) and BMI percentile (p = 0.037). For pediatric obese patients, endotoxemia has been significantly correlated only with BMI percentile (p = 0.001). Plasma cortisol did not show significant correlations with total cholesterol, triglycerides, glucose or BMI percentile. The results indicated a significant predictive power of BMI percentile on inflammatory markers: IL-6 (AUC = 0.803, p < 0.001), ICAM (AUC = 0.806, p < 0.001) and endotoxemia (AUC = 0.762, p = 0.019). Additionally, BMI percentile has a significant predictive power for metabolic markers of insulin resistance (insulin value: AUC = 0.72, p < 0.001 and HOMA index: AUC = 0.68, p = 0.003).

CONCLUSIONS

The study highlighted the importance of early markers of cardiovascular risk in obese pediatric patients represented by IL-6, ICAM, endotoxemia and their correlation with metabolic markers of insulin resistance represented by insulinemia, HOMA index and plasma cortisol. It can clearly be considered that the BMI percentile has significant predictive power for metabolic markers of insulin resistance.

Cardiometabolic risk factors and early indicators of vascular dysfunction: a cross-sectional cohort study in South African adolescents

OBJECTIVES

Prevalence of child and adolescents' overweight and obesity in low- and middle-income countries has increased dramatically. Simultaneously, the incidence of pre-hypertension/hypertension is also increasing in children, which, in turn, predisposes these children to the risk of cardiovascular disease (CVD) in later life. The present study assessed cardiometabolic risk factors and early indicators of vascular dysfunction in adolescents from a low socio-economic rural area in South Africa.

DESIGN

Cross-sectional cohort study.

SETTING

The study was conducted in public schools in Mthatha, OR Tambo district municipality, Eastern Cape Province, South Africa.

PARTICIPANTS

A total of 244 adolescents (188 females) of African ancestry aged 13-16 years were enrolled.

PRIMARY AND SECONDARY OUTCOME MEASURES

Anthropometric and haemodynamic measures and pulse wave velocity (PWV) were related to overweight/obesity and hypertension. Blood markers of cardiometabolic syndrome were assessed as well as vascular function (via PWV).

RESULTS

One-third (33.0%) of the adolescents exceeded the age and sex-specific body mass index percentiles for overweight (≥85th) or obesity (>95th) with a prevalence of 61.1% pre-hypertensives in this group. Overweight/obesity and hypertension were associated with higher triglycerides (lean:overweight: 0.79<1.01 mmol/L; normotensive:hypertensive: 0.82<0.89 mmol/L). Fasting glucose was higher in hypertensive as compared to normotensive adolescents (4.85>4.69 mmol/L, p<0.05). PWV was elevated in 25.9% of the children and significantly correlated with asymmetric dimethylarginine and systolic blood pressure (p<0.001).

CONCLUSION

Overweight/obesity and hypertension show a high prevalence in rural South African youth. Almost half of the studied adolescents are at risk for developing CVD. The high association between cardiometabolic risk factors and PWV further suggests that hypertension in adolescents may promote the progression of CVD in adulthood. Early detection of those at risk and the implementation of preventive strategies in underprivileged young people is urgently needed to stop the progression of vascular damage and manifestation of CVD in rural African children.

Feasibility and Tolerance of Fingertip Peripheral Arterial Tonometry Measurements in School-Aged Children

Background: Assessment of the endothelial function of the microvasculature by peripheral arterial tonometry (PAT) has gained increasing popularity in pediatrics. Discomfort or experienced pain during fingertip PAT has only been studied in adolescents and adults. Methods: In 142 children (aged 4-11 years old), a fingertip PAT with a commercial device (EndoPAT 2000®) as well as a caliper and ultrasound examination of peripheral skinfolds were performed as part of a cross-sectional cohort study. In 110 children, Faces Pain Scale (FPS-R) data were collected after PAT and skinfold measurements by caliper and ultrasound. Results: In 111 out of the 142 PAT measurements (78.2%), a reactive hyperemia index (RHI) could be obtained. The most frequent error messages by the software was a "too noisy" and/or a "poor quality" signal. The success rate was higher in children aged older than 6 years (83.1 vs. 44.4%; p < 0.001). Median (range) FPS-R after PAT was 0 (range 0-6) but was significantly higher than the median pain experienced after caliper measurements of peripheral skinfolds (p < 0.001). No pain was experienced by 59 of the 110 children (54.1%). Conclusion: PAT testing is feasible in the great majority of school-aged children, and the procedure is well-tolerated.

Sedentary Behavior in Childhood, Lower Arterial Compliance and Decreased Endothelial Function-Cross Sectional Data From a German School Cohort

BACKGROUND

Endothelial function by flow-mediated dilatation assesses early markers of atherosclerotic progression. Greater amounts of physical activity and physical fitness in children are associated with cardiovascular health benefits. We aimed to explore factors, influencing endothelial function and arterial compliance in a cohort of healthy school children.

METHODS

The 94 participants (41 girls, 53 boys) in the study were young, healthy children from a German school cohort. Anthropometric data, body composition and blood pressure were assessed. Blood was drawn (8 h overnight fast), assessing total cholesterol, high density lipoprotein and low density lipoprotein and triglycerides. Endothelial function was diagnosed by flow-mediated dilatation with ultrasonography (ALOKA/Hitachi, Prosound alpha 6). Tracking gates were set on the intima in B-mode. The waveform of diameter changes over the cardiac cycle was displayed in real time using the FMD-mode of the eTRACKING system. Changes in arterial diameter at baseline, ischaemia and vasodilatation were measured. A symptom limited pulmonary exercise test on a bicycle ergometer was performed to test cardiorespiratory fitness. Physical activity was assessed using GT3x accelerometers (Actigraph, USA), over 4 days (including 1 week-end day), with a minimum wear-time duration of 10 h.

RESULTS

The median age was 12.2 years (11.8-12.8). Children were normal weight, blood lipid profiles (cholesterol, high-density lipoprotein, low-density lipoprotein, triglyceride) were in normal range. Baseline measurements during the diagnostics of endothelial function revealed higher arterial compliance of the brachial artery in boys. Boys' cardiorespiratory fitness was higher than compared to girls. Boys met the recommendations of 60 min moderate to vigorous activity, whereas girls were significantly less active and did not meet current recommendations. More time spent in sedentary activity was the main predictor for lower arterial compliance (adjusted for age and sex), accounting for 14% of the variance. No significant model revealed, analyzing the influencing factors such as anthropometric data, blood lipids, physical activity and fitness on endothelial function.

CONCLUSION

This is the first study on endothelial function in association to objectively measured physical activity and cardiorespiratory fitness in healthy school children in Germany. The study highlights the importance of reducing time spent being sedentary to maintain endothelial health.

Iron Metabolism in Obesity and Metabolic Syndrome

Obesity is an excessive adipose tissue accumulation that may have detrimental effects on health. Particularly, childhood obesity has become one of the main public health problems in the 21st century, since its prevalence has widely increased in recent years. Childhood obesity is intimately related to the development of several comorbidities such as nonalcoholic fatty liver disease, dyslipidemia, type 2 diabetes mellitus, non-congenital cardiovascular disease, chronic inflammation and anemia, among others. Within this tangled interplay between these comorbidities and associated pathological conditions, obesity has been closely linked to important perturbations in iron metabolism. Iron is the second most abundant metal on Earth, but its bioavailability is hampered by its ability to form highly insoluble oxides, with iron deficiency being the most common nutritional disorder. Although every living organism requires iron, it may also cause toxic oxygen damage by generating oxygen free radicals through the Fenton reaction. Thus, iron homeostasis and metabolism must be tightly regulated in humans at every level (i.e., absorption, storage, transport, recycling). Dysregulation of any step involved in iron metabolism may lead to iron deficiencies and, eventually, to the anemic state related to obesity. In this review article, we summarize the existent evidence on the role of the most recently described components of iron metabolism and their alterations in obesity.

Leukocyte-Endothelium Interaction Is Associated with Fat Mass in Children

OBJECTIVE

To study leukocyte-endothelium interaction, a measure of the initial phase of atheromatosis, in children with overweight or obesity.

STUDY DESIGN

A prospective study was conducted in 77 children aged 7-16 years; 47 were children with overweight/obesity and 30 were normal weight. Polymorphonuclear neutrophils (PMNs) and peripheral blood mononuclear cells were isolated from venous blood samples and the interaction of leukocytes over a monolayer of human umbilical vein endothelial cells was analyzed using flow chamber microscopy. The variables studied included leukocyte rolling velocity, rolling flux, and adhesion to endothelial cells. These were compared between children with overweight/obesity and control children. Correlation between the measures of leukocyte-endothelium interaction and anthropometric and biochemical variables was evaluated.

RESULTS

In comparison with normal weight children, the PMNs and peripheral blood mononuclear cells of the overweight/obesity group showed a reduction in rolling velocity (P = .000 and P = .001, respectively) and an increase in rolling flux (P = .001 and P = .004), and adhesion (P = .003 and P = .002). The homeostasis model of insulin resistance was correlated inversely with rolling velocity and positively with rolling flux in PMNs. C-reactive protein was correlated positively with rolling flux and adhesion in both types of leucocytes. Fat mass index was correlated with all measures of leukocyte-endothelial interaction and proved to be the main predictor of leukocyte adhesion in the multiple regression analysis (P = .001 for PMNs and P = .006 for peripheral blood mononuclear cells).

CONCLUSIONS

Excess fat mass in children is related to the activation of the leukocyte-endothelium interaction, potentially contributing to the development of atherosclerosis.

The cardiovascular risk in paediatrics: the paradigm of the obstructive sleep apnoea syndrome

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) describes a spectrum of abnormal breathing patterns during sleep characterised by snoring, increased upper airway resistance and pharyngeal collapsibility, with alteration of normal oxygenation and ventilation. Intermittent desaturations during sleep have multi-organ implications. Adults with OSAS have an increased risk of developing a dysfunctional endothelium that is characterised by greater adherence of inflammatory mediators to endothelial cells and hypercoagulability. There is increasing evidence to show that risk factors for comorbid cardiovascular disease (CVD) can develop during childhood and adolescence and are likely to continue over time. Risk factors for CVD include both modifiable factors and factors that cannot be changed.

MATERIALS AND METHODS

Using the MEDLINE^® electronic database, we reviewed the scientific literature for published studies evaluating the association between sleep-disordered breathing and cardiovascular damage in children.

RESULTS

In this review, we show the role of blood markers in demonstrating the inflammation caused by intermitted oxygen desaturations during sleep in both healthy and obese children. Several instrumental techniques, in addition to serum biomarkers, can be used to assess vascular endothelial damage and its deterioration in the form of a pre-atherosclerotic condition. The confirmation of their role as markers of inflammation and vascular damage is supported by normalisation after resolution or improvement of the sleep-disordered breathing with surgery.

DISCUSSION

Great attention should be given to this condition in infants and children as it will significantly affect their present and future well-being as they grow into adulthood. Healthcare professionals, especially paediatricians, should be trained to recognise the signs and symptoms of the disease in order to send children forward for specialist care in centres dealing with sleep-disordered breathing.

Childhood obesity: Aetiology, comorbidities, and treatment

Obesity is currently considered a global epidemic, and its implications in mortality and morbidity in a paediatric patient and in adulthood are increasingly important. The objective of this article is to review in detail the definition of obesity according to age group, and, in turn, the epidemiology of this entity worldwide and in South America. Available evidence about pathophysiology and, additionally, associated comorbidities are reported in some of the most important and clinically relevant body systems. The recommendations on pharmacological and nonpharmacological management through changes in lifestyle and relevant aspects of bariatric surgery in the paediatric population are also described.

Beneficial effects of a lifestyle intervention program on C-reactive protein: impact of cardiorespiratory fitness in obese adolescents with sleep disturbances

The objectives of this study were to assess the relationship between inflammation and obstructive sleep apnea (OSA) and determine whether the lifestyle program's effects on inflammatory markers are associated with changes in anthropometric parameters, cardiorespiratory fitness, sleep duration, and OSA severity in severely obese adolescents. Participants were aged 14.6 (SD 1.2) yr, with a body mass index (BMI) of 40.2 (SD 6.5) kg/m². Sleep, anthropometric parameters, glucose metabolism, inflammatory profile, and cardiorespiratory fitness [V̇o_2peak relative to body weight (V̇o_2peakBW) and fat-free mass (V̇o_2peakFFM)] were assessed at admission and at the end of a 9-mo lifestyle intervention program (LIP). Associations between C-reactive protein (CRP) concentrations and BMI, sex, oxygen desaturation index (ODI), sleep fragmentation, total sleep time (TST), and V̇o_2peak were assessed via ANCOVA. Twenty-three subjects completed the study. OSA subjects ( n = 13) exhibited higher CRP concentrations and a trend for higher BMI than non-OSA subjects ( P = 0.09) at admission. After intervention, OSA was normalized in six subjects, and CRP significantly decreased in the OSA group and in the whole population. In both groups, leptin levels significantly decreased, whereas adiponectin concentrations increased. At admission, BMI adjusted for sex, arousal index, ODI, TST, and V̇o_2peakBW was associated with CRP levels (adjusted r² = 0.32, P < 0.05). The decrease in CRP concentrations postintervention was associated with enhanced V̇o_2peakFFM adjusted for sex, weight loss, and changed sleep parameters (adjusted r² = 0.75, P < 0.05). Despite higher amounts of CRP in OSA subjects, obesity severity outweighs the proinflammatory effects of OSA, short sleep duration, and low cardiorespiratory fitness. However, enhanced cardiorespiratory fitness is associated with the decrease of inflammation after controlling for the same parameters.

Effect of an 8-Week Individualized Training Program on Blood Biomarkers, Adipokines and Endothelial Function in Obese Young Adolescents with and without Metabolic Syndrome

Obesity is a chronic condition whose incidence is growing due to lack of exercise and frequent nutrition disorders. Childhood obesity has reached epidemic proportions worldwide. One of the best treatment methods is physical training. However, conflicting results have been reported regarding its clinical effectiveness. These contrasting findings may be due to the type and intensity of the adopted physical training program. Therefore, the purpose of the current study was to investigate the effect of an 8-week individualized physical training program on endothelial function, blood biomarkers and adipokine levels in obese adolescents with and without metabolic syndrome (MS). One-hundred-and-twenty-two obese adolescents (71 obese without MS and 51 obese with MS) aged 14 ± 2 years were included in this study. The 8-week individualized training program decreased glucose, triglycerides, total cholesterol, low-density lipoprotein cholesterol and leptin in obese subjects with and without MS. However, adiponectin and endothelial-dependent vasodilatation increased in the follow-up study in both groups. Taken together, the findings suggest that individualized training program is an effective means for the treatment of obesity and MS in pediatric populations.

Exosomal Cargo Properties, Endothelial Function and Treatment of Obesity Hypoventilation Syndrome: A Proof of Concept Study

STUDY OBJECTIVES

Longitudinal studies support the usage of positive airway pressure (PAP) therapy in treating obstructive sleep apnea (OSA) to improve cardiovascular disease. However, the anticipated benefit is not ubiquitous. In this study, we elucidate whether PAP therapy leads to immediate improvements on endothelial function, a subclinical marker of cardiovascular status, by examining the effect of circulating exosomes, isolated from patients before and after PAP therapy, on naive endothelial cells.

METHODS

We isolated plasma-derived circulating exosomes from 12 patients with severe OSA and obesity hypoventilation syndrome (OHS) before and after 6 weeks of PAP therapy, and examined their effect on cultured endothelial cells using several in vitro reporter assays.

RESULTS

We found that circulating exosomes contributed to the induction and propagation of OSA/OHS-related endothelial dysfunction (ie, increased permeability and disruption of tight junctions along with increased adhesion molecule expression, and reduced endothelial nitric oxide synthase expression), and promoted increased monocyte adherence. Further, when comparing exosomes isolated before and after PAP therapy, the disturbances in endothelial cell function were attenuated with treatment, including an overall cumulative decrease in endothelial permeability in all 12 subjects by 10.8% (P = .035), as well as detection of a subset of 4 differentially expressed exosomal miRNAs, even in the absence of parallel changes in systemic blood pressure or metabolic function.

CONCLUSIONS

Circulating exosomes facilitate important intercellular signals that modify endothelial phenotype, and thus emerge as potential fundamental contributors in the context of OSA/OHS-related endothelial dysfunction. Exosomes may not only provide candidate biomarkers, but are also a likely and plausible mechanism toward OSA/OHS-induced cardiovascular disease.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov, Title: AVAPS-AE Efficacy Study, URL: https://clinicaltrials.gov/ct2/show/NCT01368614, Identifier: NCT01368614.

Comparison of retinal vascular geometry in obese and non-obese children

Purpose

Childhood obesity is associated with adult cardiometabolic disease. We postulate that the underlying microvascular dysfunction begins in childhood. We thus aimed to compare retinal vascular parameters between obese and non-obese children.

Methods

This was a cross-sectional study involving 166 children aged 6 to 12 years old in Malaysia. Ocular examination, biometry, retinal photography, blood pressure and body mass index measurement were performed. Participants were divided into two groups; obese and non-obese. Retinal vascular parameters were measured using validated software.

Results

Mean age was 9.58 years. Approximately 51.2% were obese. Obese children had significantly narrower retinal arteriolar caliber (F_(1,159) = 6.862, p = 0.010), lower arteriovenous ratio (F_(1,159) = 17.412, p < 0.001), higher venular fractal dimension (F_(1,159) = 4.313, p = 0.039) and higher venular curvature tortuosity (F_(1,158) = 5.166, p = 0.024) than non-obese children, after adjustment for age, gender, blood pressure and axial length.

Conclusions

Obese children have abnormal retinal vascular geometry. These findings suggest that childhood obesity is characterized by early microvascular abnormalities that precede development of overt disease. Further research is warranted to determine if these parameters represent viable biomarkers for risk stratification in obesity.

Effect of Exercise Intervention on Flow-Mediated Dilation in Overweight and Obese Adults: Meta-Analysis

The objective of this meta-analysis is to summarize the effect of exercise intervention on flow-mediated dilatation (FMD) in overweight and obese adults. We searched four electronic databases (PubMed/Medline, Scopus, and CINAHL) through June 2016 for relevant studies pertaining to the effectiveness of exercise intervention on FMD. Seventeen of the 91 studies identified met the inclusion criteria. Comprehensive Meta-Analysis software (version 3) was used to compute the standardized mean difference effect size (ES) and 95% CI using a random effects model. We calculated 34 ESs. We found that exercise intervention had medium and positive effects on FMD, with an overall ES of 0.522 (95% CI = 0.257, 0.786). Heterogeneity of ESs was observed (Q_b = 239, p ≤ 0.001, I² = 86.19), and the effect was moderated by comorbidity (Q_b = 6.39, df = 1, p = 0.011). A large ES for the combination exercise, low intensity exercise, and comorbidity subgroups (ES = 0.82~1.24) was found. We conclude that while exercise intervention significantly improves FMD in overweight and obese adults, the effect may depend on the different characteristics of exercise intervention and on participants' demographics.

Targeting Endothelial Function to Treat Heart Failure with Preserved Ejection Fraction: The Promise of Exercise Training

Although the burden of heart failure with preserved ejection fraction (HFpEF) is increasing, there is no therapy available that improves prognosis. Clinical trials using beta blockers and angiotensin converting enzyme inhibitors, cardiac-targeting drugs that reduce mortality in heart failure with reduced ejection fraction (HFrEF), have had disappointing results in HFpEF patients. A new “whole-systems” approach has been proposed for designing future HFpEF therapies, moving focus from the cardiomyocyte to the endothelium. Indeed, dysfunction of endothelial cells throughout the entire cardiovascular system is suggested as a central mechanism in HFpEF pathophysiology. The objective of this review is to provide an overview of current knowledge regarding endothelial dysfunction in HFpEF. We discuss the molecular and cellular mechanisms leading to endothelial dysfunction and the extent, presence, and prognostic importance of clinical endothelial dysfunction in different vascular beds. We also consider implications towards exercise training, a promising therapy targeting system-wide endothelial dysfunction in HFpEF.

Cellular mechanisms and consequences of glycation in atherosclerosis and obesity

Post-translational modification of proteins imparts diversity to protein functions. The process of glycation represents a complex set of pathways that mediates advanced glycation endproduct (AGE) formation, detoxification, intracellular disposition, extracellular release, and induction of signal transduction. These processes modulate the response to hyperglycemia, obesity, aging, inflammation, and renal failure, in which AGE formation and accumulation is facilitated. It has been shown that endogenous anti-AGE protective mechanisms are thwarted in chronic disease, thereby amplifying accumulation and detrimental cellular actions of these species. Atop these considerations, receptor for advanced glycation endproducts (RAGE)-mediated pathways downregulate expression and activity of the key anti-AGE detoxification enzyme, glyoxalase-1 (GLO1), thereby setting in motion an interminable feed-forward loop in which AGE-mediated cellular perturbation is not readily extinguished. In this review, we consider recent work in the field highlighting roles for glycation in obesity and atherosclerosis and discuss emerging strategies to block the adverse consequences of AGEs. This article is part of a Special Issue entitled: The role of post-translational protein modifications on heart and vascular metabolism edited by Jason R.B. Dyck & Jan F.C. Glatz.