Postprandial endothelial function, inflammation, and oxidative stress in obese children and adolescents

Childhood Cardiovascular Health, Obesity, and Some Related Disorders: Insights into Chronic Inflammation and Oxidative Stress

Childhood obesity and associated metabolic abnormalities have become pressing public health concerns worldwide, significantly impacting cardiovascular health. Metabolic syndrome, characterized by a cluster of metabolic abnormalities including central obesity, altered glucose metabolism, dyslipidemia, and arterial hypertension, has emerged as a critical precursor to cardiovascular disease. Chronic systemic inflammation and oxidative stress seem to play pivotal roles in the pathogenesis of childhood obesity-related disorders such as early atherosclerosis. A significant distinction between the objective components of cardiovascular health metrics, including body mass index, blood pressure, cholesterol, and fasting glucose levels, and the definition of metabolic syndrome is evident in the identification of obesity. Whereas cardiovascular health metrics predominantly rely on body mass index percentiles to assess obesity, metabolic syndrome criteria prioritize waist circumference, specifically targeting individuals with a measurement ≥90th percentile. This discrepancy emphasizes the need for a nuanced approach in assessing the risks associated with obesity and underscores the importance of considering multiple factors when evaluating cardiovascular risk in children. By recognizing the complex interplay between various health metrics, obesity and metabolic syndrome criteria, clinicians can more accurately identify individuals at risk and tailor interventions accordingly to mitigate cardiovascular disease in children with obesity.

Arsenic exposure from drinking water and endothelial dysfunction in Bangladeshi adolescents

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide, with ∼80% of CVD-related deaths occurring in low- and middle-income countries. Growing evidence suggests that chronic arsenic exposure may contribute to CVD through its effect on endothelial function in adults. However, few studies have examined the influence of arsenic exposure on cardiovascular health in children and adolescents. To examine arsenic's relation to preclinical markers of endothelial dysfunction, we enrolled 200 adolescent children (ages 15-19 years; median 17) of adult participants in the Health Effects of Arsenic Longitudinal Study (HEALS), in Araihazar, Bangladesh. Participants' arsenic exposure was determined by recall of lifetime well usage for drinking water. As part of HEALS, wells were color-coded to indicate arsenic level (<10 μg/L, 10-50 μg/L, >50 μg/L). Endothelial function was measured by recording fingertip arterial pulsatile volume change and reactive hyperemia index (RHI) score, an independent CVD risk factor, was calculated from these measurements. In linear regression models adjusted for participant's sex, age, education, maternal education, land ownership and body weight, individuals who reported always drinking water from wells with >50 μg/L arsenic had a 11.75% lower level of RHI (95% CI: -21.26, -1.09, p = 0.03), as compared to participants who drank exclusively from wells with ≤50 μg/L arsenic. Sex-stratified analyses suggest that these associations were stronger in female participants. As compared to individuals who drank exclusively from wells with ≤50 μg/L arsenic, the use of wells with >50 μg/L arsenic was associated with 14.36% lower RHI (95% CI: -25.69, -1.29, p = 0.03) in females, as compared to 5.35% lower RHI (95% CI: -22.28, 15.37, p = 0.58) in males for the same comparison. Our results suggest that chronic arsenic exposure may be related to endothelial dysfunction in adolescents, especially among females. Further work is needed to confirm these findings and examine whether these changes may increase risk of later adverse cardiovascular health events.

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

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

Effects of a diet based on the Dietary Guidelines on vascular health and TMAO in women with cardiometabolic risk factors

BACKGROUND AND AIMS

Recent evidence links trimethylamine oxide (TMAO) to endothelial dysfunction, an early indicator of cardiovascular disease. We aimed to determine whether short-term consumption of a diet patterned after the 2010 Dietary Guidelines for Americans (DGA) would affect endothelial function, plasma TMAO concentrations, and cardiovascular disease risk, differently than a typical American Diet (TAD).

METHODS AND RESULTS

An 8-wk controlled feeding trial was conducted in overweight/obese women pre-screened for insulin resistance and/or dyslipidemia. Women were randomized to a DGA or TAD group (n = 22/group). At wk0 (pre-intervention) and wk8 (post-intervention) vascular age was calculated; endothelial function (reactive hyperemia index (RHI)) and augmentation index (AI@75) were measured using EndoPAT, and plasma TMAO was measured by LC-MS/MS. Vascular age was reduced in DGA at wk8 compared to wk0 but TAD wk8 was not different from wk0 (DGA wk0: 54.2 ± 4.0 vs. wk8: 50.5 ± 3.1 (p = 0.05), vs. TAD wk8: 47.7 ± 2.3). Plasma TMAO concentrations, RHI, and AI@75 were not different between groups or weeks.

CONCLUSION

Consumption of a diet based on the 2010 Dietary Guidelines for Americans for 8 weeks did not improve endothelial function or reduce plasma TMAO. CLINICALTRIALS.GOV: NCT02298725.

The acute and postprandial effects of sugar moiety on vascular and metabolic health outcomes in adolescents

This study explored the cardiometabolic responses to sugar moieties acutely, and following a subsequent mixed meal tolerance test (MMTT). Twenty-one healthy adolescents (N = 10 female, 14.3 ± 0.4 years) completed 3 experimental and 1 control condition, in a counterbalanced order. These consisted of different drinks to compare the effect of 300 mL of water (control), or 300 mL of water mixed with 60 g of glucose, fructose or sucrose, on vascular function (flow-mediated dilation (FMD), microvascular reactivity (total hyperaemic response; TRH), and cerebrovascular reactivity (CVR)), and blood samples for uric acid, glucose, triglycerides and lactate concentrations. FMD increased 1 h after glucose and sucrose (P < 0.001, ES ≥ 0.92) but was unchanged following fructose and water (P ≥ 0.19, ES ≥ 0.09). CVR and TRH were unchanged 1 h following all conditions (P > 0.57, effect size (ES) > 0.02). Following the MMTT, FMD was impaired in all conditions (P < 0.001, ES > 0.40) with no differences between conditions (P > 0.13, ES < 0.39). Microvascular TRH was increased in all conditions (P = 0.001, ES = 0.88), and CVR was preserved in all conditions after MMTT (P = 0.87, ES = 0.02). Blood uric acid concentration was elevated following fructose consumption and the MMTT (P < 0.01, ES > 0.40). Consumption of a sugar sweetened beverage did not result in vascular dysfunction in healthy adolescents; however, the vascular and metabolic responses were dependent on sugar moiety. Novelty: Glucose consumption acutely increases peripheral vascular function in healthy adolescents. Acute sugar sweetened beverage consumption (sucrose) does not result in adverse vascular outcomes. Elevations in uric acid are observed with fructose consumption, which may have implications over repeated exposure.

The acute effect of high- and moderate-intensity interval exercise on vascular function before and after a glucose challenge in adolescents

NEW FINDINGS

What is the central question of this study? What is the effect of high-intensity and moderate-intensity interval running on macro- and microvascular function in a fasted state and following a glucose challenge in adolescents? What is the main finding and its importance? Both macro- and microvascular function were improved after interval running independent of intensity. This finding shows that the intermittent exercise pattern and its associated effect on shear are important for vascular benefits. In adolescents, macrovascular function was enhanced after an acute glucose load. However, the effect of chronic glucose consumption on vascular function remains to be elucidated.

ABSTRACT

Interventions targeting vascular function in youth are an important strategy for the primary prevention of cardiovascular diseases. This study examined, in adolescents, the effect of high-intensity interval running (HIIR) and moderate-intensity interval running (MIIR) on vascular function in a fasted state and postprandially after a glucose challenge. Fifteen adolescents (13 male, 13.9 ± 0.6 years) completed the following conditions on separate days in a counterbalanced order: (1) 8 × 1 min HIIR interspersed with 75 s recovery; (2) distance-matched amount of 1 min MIIR interspersed with 75 s recovery; and (3) rest (CON). Macro- (flow-mediated dilatation, FMD) and microvascular (peak reactive hyperaemia, PRH) function were assessed immediately before and 90 min after exercise/rest. Participants underwent an oral glucose tolerance test (OGTT) 2 h after exercise/rest before another assessment of vascular function 90 min after the OGTT. Following exercise, both HIIR and MIIR increased FMD (P = 0.02 and P = 0.03, respectively) and PRH (P = 0.04, and P = 0.01, respectively) with no change in CON (FMD: P = 0.51; PRH: P = 0.16) and no significant differences between exercise conditions. Following the OGTT, FMD increased in CON (P < 0.01) with no changes in HIIR and MIIR (both P > 0.59). There was no change in PRH after the OGTT (all P > 0.40). In conclusion, vascular function is improved after interval running independent of intensity in adolescents. Acute hyperglycaemia increased FMD, but prior exercise did not change vascular function after the OGTT in youth.

Effects of Low-Fat and High-Fat Meals, with and without Dietary Fiber, on Postprandial Endothelial Function, Triglyceridemia, and Glycemia in Adolescents

The consumption of fiber-rich foods may negate the deleterious effects of high-fat meals on postprandial triglyceridemia and endothelial function. Despite supportive data in adults, little is known about the effects of high-fat and high-fiber foods on cardiovascular health parameters in pediatric populations. In this crossover trial, male and female adolescents (n = 10; 14.1 + 2.6 years; range 10–17 years) consumed (1) low-fat, low-fiber, (2) low-fat, high-fiber, (3) high-fat, low-fiber, and (4) high-fat, high-fiber breakfast meals in randomized order, each following an overnight fast. Baseline and 4 h post-meal blood was obtained for determination of glucose, insulin and triglyceride concentrations. Endothelial function was assessed via brachial artery flow-mediated dilation (FMD). Postprandial FMD was not significantly changed after any meal. However, regression analyses revealed a significant inverse relationship between the change in 4 h triglyceride concentration and change in 4 h FMD for the high-fat, low-fiber meal (β = −0.087; 95% CI = −0.138 to −0.037; p = 0.001) that was no longer significant in the high-fat, high-fiber meal (β = −0.044; 95% CI = −0.117 to 0.029; p = 0.227). Interpretation of these analyses must be qualified by acknowledging that between-meal comparison revealed that the two regression lines were not statistically different (p = 0.226). Addition of high-fiber cereal to the high-fat meal also reduced 4 h postprandial triglyceride increases by ~50% (p = 0.056). A high-fiber breakfast cereal did not attenuate postprandial glucose and insulin responses after consumption of a low-fat meal. While further work is needed to confirm these results in larger cohorts, our findings indicate the potential importance of cereal fiber in blunting the inverse relationship between postprandial hypertriglyceridemia and FMD after consumption of a high-fat meal in adolescents.

Effects of Glucose Ingestion on Serum Fractalkine Levels in Healthy Subjects and Newly Diagnosed Type 2 Diabetic Patients

BACKGROUND

Fractalkine (FKN) is an inflammatory cytokine that has been shown with increased serum levels in diabetic patients and is considered to contribute to the adipose tissue inflammation by supporting monocyte adhesion to adipocytes which has an important role in the pathogenesis of type 2 diabetes mellitus (T2DM). Our aim was to evaluate the effects of glucose ingestion on the serum fractal - kine levels in healthy subjects with normal glucose tolerance (NGT) and newly diagnosed T2DM patients.

METHODS

A total of 67 patients were included in this study, and they were divided into NGT (n=34) and T2DM (n=33) groups according to their oral glucose tolerance test (OGTT) results. The serum FKN and C-reactive protein (CRP) levels were measured at 0 and 120 minutes during an OGTT following overnight fasting.

RESULTS

The 0-minute (basal) and 120-minute OGTT FKN levels were found to be significantly higher in the T2DM group when compared to the NGT group (p=0.012 and p=0.001, respectively). However, no significant differences were observed in terms of the changes in the basal and 120-minute OGTT FKN levels in the T2DM and NGT groups (p=0.433 and p=0.06, respectively). A significant positive correlation was observed between the 120-minute OGTT FKN and glucose levels in the study group consisting of all of the patients (r=0.331, p=0.006).

CONCLUSIONS

In this study, basal and post-glycemic load FKN levels were found to be higher in newly diagnosed T2DM patients than those with NGT; however, there was no additional change in FKN levels by glycemic load.

Phenotypic flexibility as a measure of health: the optimal nutritional stress response test

Nutrition research is struggling to demonstrate beneficial health effects, since nutritional effects are often subtle and long term. Health has been redefined as the ability of our body to cope with daily-life challenges. Physiology acts as a well-orchestrated machinery to adapt to the continuously changing environment. We term this adaptive capacity “phenotypic flexibility.” The phenotypic flexibility concept implies that health can be measured by the ability to adapt to conditions of temporary stress, such as physical exercise, infections or mental stress, in a healthy manner. This may offer a more sensitive way to assess changes in health status of healthy subjects. Here, we performed a systematic review of 61 studies applying different nutritional stress tests to quantify health and nutritional health effects, with the objective to define an optimal nutritional stress test that has the potential to be adopted as the golden standard in nutrition research. To acknowledge the multi-target role of nutrition, a relevant subset of 50 processes that govern optimal health, with high relevance to diet, was used to define phenotypic flexibility. Subsequently, we assessed the response of biomarkers related to this subset of processes to the different challenge tests. Based on the obtained insights, we propose a nutritional stress test composed of a high-fat, high-caloric drink, containing 60 g palm olein, 75 g glucose and 20 g dairy protein in a total volume of 400 ml. The use of such a standardized nutritional challenge test in intervention studies is expected to demonstrate subtle improvements of phenotypic flexibility, thereby enabling substantiation of nutritional health effects.

Feasibility and preliminary efficacy of the effects of flavanoid-rich purple grape juice on the vascular health of childhood cancer survivors: a randomized, controlled crossover trial

BACKGROUND

Childhood cancer survivors have an increased risk of developing cardiovascular disease following treatment, yet few interventions have been evaluated to reduce this risk. Purple grape juice (pGJ), a rich source of flavonoids with antioxidant properties, has been shown in adults to reduce oxidative stress and improve endothelial function. We examined the effects of supplementing meals with pGJ on microvascular endothelial function and markers of oxidative stress and inflammation in 24 cancer survivors (ages 10-21 years).

PROCEDURE

In a randomized controlled crossover trial consisting of two, 4 week intervention periods, each preceded by a 4 week washout period, subjects received in random order 6 ounces twice daily of pGJ and clear apple juice (cAJ; similar in calories but lower in flavonoids). Measurements were obtained before and after each supplementation period; change was evaluated using mixed effects ANOVA.

RESULTS

pGJ did not improve endothelial function, measured using digital reactive hyperemia, compared with cAJ (mean change: pGJ 0.06, cAJ 0.22; difference of mean change [95% CI]: -0.16 [-0.42 - 0.11], P = 0.25). No significant changes in plasma concentrations of oxidized-LDL, myeloperoxidase, or high sensitivity C-reactive protein were observed.

CONCLUSION

After 4 weeks of daily consumption of flavonoid-rich pGJ, no measurable change in vascular function was observed in these childhood cancer survivors.

Assessment of inflammatory resilience in healthy subjects using dietary lipid and glucose challenges

BACKGROUND

Resilience or the ability of our body to cope with daily-life challenges has been proposed as a new definition of health, with restoration of homeostasis as target resultant of various physiological stress responses. Challenge models may thus be a sensitive measure to study the body's health. The objective of this study was to select a dietary challenge model for the assessment of inflammatory resilience. Meals are a challenge to metabolic homeostasis and are suggested to affect inflammatory pathways, yet data in literature are limited and inconsistent.

METHOD

The kinetic responses of three different dietary challenges and a water control challenge were assessed on various metabolic and inflammatory markers in 14 healthy males and females using a full cross-over study design. The dietary challenges included glucose (75 g glucose in 300 ml water), lipids (200 ml whipping cream) and a mix of glucose and lipids (same amounts as above), respectively. Blood samples were collected at baseline and at 0.5, 1, 2, 4, 6, 8 and 10 h after consumption of the treatment products. Inflammation (IFNγ, IL-1β, IL-6, IL-8, IL-10, IL-12p70, TNF-α CRP, ICAM-1, VCAM-1, SAA, E-selectin, P-selectin, thrombomodulin, leukocytes, neutrophils, lymphocytes) and clinical (e.g. glucose, insulin, triglycerides) markers as well as gene expression in blood cells and plasma oxylipin profiles were measured.

RESULTS

All three dietary challenges induced changes related to metabolic control such as increases in glucose and insulin after the glucose challenge and increases in triglycerides after the lipid challenge. In addition, differences between the challenges were observed for precursor oxylipins and some downstream metabolites including DiHETrE's and HODE's. However, none of the dietary challenges induced an acute inflammatory response, except for a modest increase in circulating leukocyte numbers after the glucose and mix challenges. Furthermore, subtle, yet statistically significant increases in vascular inflammatory markers (sICAM-1 and sVCAM-1) were found after the mix challenge, when compared to the water control challenge.

CONCLUSIONS

This study shows that dietary glucose and lipid challenges did not induce a strong acute inflammatory response in healthy subjects, as quantified by an accurate and broad panel of parameters.

Arterial compliance is increased in children with type 2 diabetes compared with normal weight peers but not obese peers

BACKGROUND

We reported that obesity was associated with increased arterial compliance in children, possibly due to accelerated vascular maturation. Here, we explored the additional burden of type 2 diabetes (T2DM) on vascular function in children.

METHODS

Fifty normal weight [body mass index (BMI) 25-75%], 58 obese (BMI ≥ 95%), and 34 children with T2DM diagnosed by American Diabetes Association (ADA) criteria ages 10-18 yr were studied. Large and small artery elasticity (LAEI and SAEI, respectively) were measured by diastolic pulse-wave contour analysis.

RESULTS

SAEI was 27% higher in children with T2DM compared to normal weight children (p = 0.005). Mean LAEI for those with T2DM not different from either group. In the group with T2DM, both SAEI and LAEI increased with age up to 16 yr, but declined thereafter. The strongest multivariable model predicting SAEI in children with T2DM combined lean mass, systolic blood pressure (SBP), and glucose (r2  = 0.59); for predicting LAEI, the strongest model included height, SBP, and low-density lipid-cholesterol (r2  = 0.61).

CONCLUSION

The lower arterial compliance in older adolescents with T2DM compared to that of their peers without diabetes may indicate a premature maturation of the vascular system; however, follow-up will clarify whether these vascular changes portend an early increase in diabetes-associated cardiovascular disease risk.

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.

Effect of glucose ingestion in plasma markers of inflammation and oxidative stress: analysis of 16 plasma markers from oral glucose tolerance test samples of normal and diabetic patients

Sixteen plasma markers of inflammation and oxidative stress were measured during OGTT in 54 subjects. Leptin, RBP4, CRP, OPN, ANG, MDC, and MCSF concentrations significantly decreased during OGTT (P<0.05). IL6, IL8, and MCP3 concentrations significantly increased during OGTT (P<0.05). These results provide evidence that glucose ingestion affects systemic inflammation and oxidative stress.

Meal frequency differentially alters postprandial triacylglycerol and insulin concentrations in obese women

OBJECTIVE

The aim of this study was to compare postprandial lipemia, oxidative stress, antioxidant activity, and insulinemia between a three and six isocaloric high-carbohydrate meal frequency pattern in obese women.

DESIGN AND METHODS

In a counterbalanced order, eight obese women completed two, 12-h conditions in which they consumed 1,500 calories (14% protein, 21% fat, and 65% carbohydrate) either as three 500 calorie liquid meals every 4-h or six 250 calorie liquid meals every 2-h. Blood samples were taken every 30 min and analyzed for triacylglycerol (TAG), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, oxidized low-density lipoprotein cholesterol, myeloperoxidase, paraoxonase-1 activity, and insulin.

RESULTS

The TAG incremental area under the curve (iAUC) during the three meal condition (321 ± 129 mg/dl · 12 h) was significantly lower (P = 0.04) compared with the six meal condition (481 ± 155 mg/dl · 12 h). The insulin iAUC during the three meal condition (5,549 ± 1,007 pmol/l · 12 h) was significantly higher (P = 0.05) compared with the six meal condition (4,230 ± 757 pmol/l(.) 12 h). Meal frequency had no influence on the other biochemical variables.

CONCLUSIONS

Collectively, a three and six isocaloric high-carbohydrate meal frequency pattern differentially alters postprandial TAG and insulin concentrations but has no effect on postprandial cholesterol, oxidative stress, or antioxidant activity in obese women.

Elevated glucose level at 30 minutes during an oral glucose tolerance test in obese adolescents: a new disorder of glucose tolerance

We observed glucose levels >140 mg/dL measured at 30 minutes (min) during an oral glucose tolerance test (OGTT) in some obese patients. We aimed to investigate the significance of this finding by comparing lipid profiles, insulin resistance indices, and systemic inflammatory mediators between obese adolescents with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and elevated glucose levels at 30 min. The study involved 80 obese (body mass index >95(th) percentile for age and sex) adolescents (48 female, 32 male) between 11 and 16 years of age. Depending on OGTT results, patients were divided into NGT and IGT groups. The third group was recruited from the NGT group as having glucose levels > 140 mg/dL at 30 minutes. Lipid profiles, [interleukin-6 (IL-6)], neopterin, and lipoprotein associated phospholipase A₂ (Lp-PLA₂)] were assessed. Neopterin and Lp-PLA₂ levels were significantly higher in obese adolescents with elevated glucose levels at 30 min. compared with those in both NGT and IGT groups (p=0.013, and 0.004, respectively). In these adolescents, IL-6 levels were significantly higher only than the NGT group (p=0.01). In logistic regression analysis, IL-6, neopterin and Lp-PLA₂ levels were detected to be related to high blood glucose levels at 30 min (OR 1.11, p=0.01; OR 9.03, p=0.013; OR 1.01, p=0.004 respectively). Obese adolescents with elevated glucose levels at 30 min. demonstrated higher inflammatory mediators levels, which were atherosclerotic indicators, than obese adolescents with NGT and IGT. These results suggest that glucose levels >140 mg/dL measured at 30 min during an OGTT may be a new disorder of glucose tolerance in obesity.