Improvement of early vascular changes and cardiovascular risk factors in obese children after a six-month exercise program

A pediatric perspective on inflammation and oxidative stress in response to exercise

Dr. Oded Bar-Or was a giant in the area of pediatric exercise science and made numerous contributions to the health of children around the world. He also had a significant impact on a relatively new area of pediatric exercise science — pediatric exercise immunology. Under his supervision, some aspects of the immunobiology of exercise have been unravelled from a pediatric perspective. In general, healthy children experience less inflammatory stress in response to standardized exercise, while demonstrating an exercise-induced elevation in the anabolic cytokine IL-8. Mechanisms for the maturity- and age-dependent changes in cytokine responses to exercise are unknown, but may involve oxidative stress. Studies of oxidative stress and exercise in children are scant, but preliminary data suggests that, like the inflammatory cytokine response to exercise, children may experience less oxidative stress in response to intense exercise. We propose that the links between exercise, inflammatory and oxidative stress, and growth factors will be important to understand in the context of how exercise contributes to optimal growth and development during childhood. This understanding will be particularly relevant for childhood diseases that restrict growth.

Early treatment reduces the cardiovascular risk factors in newly diagnosed rheumatoid arthritis patients

OBJECTIVE

To investigate subclinical atherosclerosis and the effect of treatment in patients with early rheumatoid arthritis (RA).

PATIENTS AND METHODS

Forty patients with early RA who met the revised American College of Rheumatology (ACR) criteria and disease duration of <1 year were included in the study. Smokers and patients with classical risk factors for atherosclerosis were excluded. The serum levels of total cholesterol (TC), triglycerides, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol were determined in all patients before and after 1 year of therapy. Carotid artery intima-media thickness (IMT) and carotid plaque were measured before and after treatment. RA disease activity was measured using the 28 joint indices score (DAS-28) and clinical improvement was determined by the ACR response criteria. Forty-five age- and sex-matched nonsmoking volunteers were used as controls. All patients were treated with methotrexate and prednisone.

RESULTS

RA patients had a baseline mild dyslipidemia characterized by a decrease in serum HDL-C levels and a high TC/HDL-C atherogenic ratio compared with controls. Both lipid parameters were significantly improved after treatment (P<0.01). Common carotid artery IMTs at baseline were higher in RA patients compared with controls (P<0.05). After 1 year of therapy there was a significant decrease in the IMTs (P<0.001). Thirty-five patients (88%) achieved the ACR 20%, while 30 (75%) reached the ACR 50% response criteria. A significant decrease of DAS-28 was observed after treatment (P<0.03).

CONCLUSIONS

The atherogenic lipid profile and subclinical atherosclerosis are features of early RA, which improved after therapy. Early intervention and control of the disease activity may reduce the risk of atherosclerosis and cardiovascular events in patients with RA.

Efeito do exercício físico sobre peso corporal em crianças com excesso de peso: ensaio clínico comunitário randomizado em uma favela no Brasil

Associação da obesidade com doenças crônicas tem se mostrado mais intensa nas áreas carentes. Examinamos o efeito de um programa de exercício físico para crianças com excesso de peso, em uma favela do Recife, Pernambuco, Brasil, por meio de um ensaio comunitário, randomizado, com 78 crianças. Um grupo (n = 39) recebeu três aulas semanais de exercícios físicos durante seis meses. Não foi realizada nenhuma intervenção em relação à alimentação. A análise por intenção de tratamento demonstrou que todas as crianças apresentaram aumento significativo de peso. Entretanto, esse aumento foi menor no grupo que sofreu a intervenção (diferença média entre os grupos; -1.37; IC95%: -2,00; -0,74). Em relação ao índice de massa corporal (IMC), também foi verificada uma diferença significativa (p = 0,049) entre os dois grupos (diferença média entre os grupos; -0,53; IC95%: -1,06; -0,002). Na análise restrita às crianças que completaram o estudo (intervenção = 30 e controle = 38), os resultados foram similares. Concluímos que um programa regular de exercícios físicos para crianças com excesso de peso em áreas carentes seja eficaz, sem a necessidade de intervenções dietéticas, na redução do ganho ponderal e do IMC.

Noninvasive cardiac imaging: implications for risk assessment in adolescents and young adults

Noninvasive imaging of cardiovascular end organ injury has now been applied to adolescents and young adults to better understand the early natural history of chronic heart disease. Echocardiography, assessment of endothelial function, and subclinical atherosclerosis imaging using carotid intima-media thickness measures and coronary calcium identified on computed tomography scanning have all been applied at young ages to demonstrate adverse effects of cardiovascular risk factors. Intervention trials using these techniques as end points may improve understanding of the natural history of acquired cardiovascular disease.

Estratégias para prevenção da obesidade em crianças e adolescentes

Poucos estudos obtiveram resultados favoráveis na prevenção da obesidade. Teoricamente, crianças e adolescentes, se comparados aos adultos, poderiam mais facilmente prevenir o ganho excessivo de peso, pois estão crescendo e têm maior possibilidade de gastar energia em atividades de lazer. Entretanto, não se consegue superar os muitos fatores que concorrem para a crescente epidemia de obesidade e as intervenções na sua maioria abordam uma fração muito pequena dos fatores que geram a obesidade. Aspectos importantes, como o papel da indústria de alimentos, das cadeias de fast food, das propagandas, de um estilo de vida que mantêm as crianças cada vez mais sedentárias e submetidas a um hiperconsumo calórico, não têm espaço nos desenhos de estudos tradicionais. Das intervenções publicadas, as que integram a família no tratamento têm obtido melhores resultados. Estudos com elementos isolados da dieta como cálcio, proteína, fibras e índice glicêmico não têm mostrado eficácia, e embora não conclusivos, os resultados referentes à redução de bebidas com alto teor de açúcar e redução do sedentarismo são promissores.

Physical activity for the prevention and management of youth-onset type 2 diabetes mellitus: focus on cardiovascular complications

With the growing prevalence of childhood obesity and type 2 diabetes mellitus (T2DM) in youth, the challenge of cardiovascular disease risk management has entered the paediatric realm, affecting specialists, family physicians and allied healthcare professionals alike. Currently, there is little evidence to support optimal strategies for management of T2DM in youth and the associated cardiovascular complications. Physical activity plays a powerful role in the prevention and management of T2DM and cardiovascular disease in adults. This review will focus on the role of physical activity for the prevention of T2DM in youth and its associated cardiovascular complications. The first part describes the prevalence of cardiovascular risk factors in this cohort. The second part focuses on the role of physical activity in the prevention and management of T2DM in youth. Collectively, the limited intervention and observation studies published to date suggest that daily targets of 60-90 minutes of physical activity and less than 60 minutes of screen time (i.e. time spent in front of a television, computer or video games) are required for the prevention and management of T2DM in youth. Large-scale intervention studies are needed to determine the most effective physical activity strategies for the prevention and management of T2DM in youth.

Association of changes in oxidative and proinflammatory states with changes in vascular function after a lifestyle modification trial among obese children

BACKGROUND

The association of changes in oxidative and proinflammatory states with vascular function after diet and exercise intervention among obese children has not been previously explored.

METHODS

In this 6-week diet and exercise intervention study in 35 obese children, age 12 to 18 years, we evaluated the relationship between changes in anthropometric indices, measures of insulin resistance, C-reactive protein (CRP), oxidized LDL (ox-LDL), and oxidative stress markers with changes in carotid intima-media thickness (C-IMT) and flow mediated dilation (FMD) of the brachial artery.

RESULTS

At the end of the study, body mass index (BMI), waist circumference, and percentage body fat were decreased (P <0.05), but participants remained overweight (BMI > or = 95th percentile). Although FMD improved (P <0.05), the improvement in C-IMT did not reach statistical significance. The changes in BMI, waist circumference, fat mass, ox-LDL, malondialdehyde (MDA), CRP, insulin, and homeostasis model assessment for insulin resistance (HOMA-IR) had an inverse correlation with the changes in mean FMD after adjustment for age and sex, with the highest correlations documented for ox-LDL, CRP, and WC. The age- and sex-adjusted changes in ox-LDL, waist circumference, CRP, MDA, and body fat mass had the highest correlations with changes in C-IMT.

CONCLUSIONS

Our findings suggest that a common inflammatory stress condition associated with childhood obesity, notably with abdominal fat deposition, may play a role in the development of the earliest stages of proatherosclerotic inflammatory processes and subsequent vascular dysfunction. These changes might be partially reversible by short-term diet and exercise intervention, even if patients do not reach ideal body weight.

Childhood origins of arterial disease

PURPOSE OF REVIEW

The present article reviews the importance of classical and novel risk factors that present in childhood, track into adult life and contribute to arterial disease. The value of noninvasive techniques that can assist in characterization of preclinical atherosclerotic changes as intermediate phenotypes is also discussed.

RECENT FINDINGS

Noninvasive functional and structural techniques are now available and provide the opportunity to characterize early arterial disease long before cardiovascular complications present. By using these techniques, it has been possible to quantify the impact of conventional and novel cardiovascular risk factors seen in childhood on the development of preclinical atherosclerotic changes. Scientific interest has recently widened to include not only study of mechanisms and biomarkers of injury but also mechanisms that promote vascular repair. In this new field, characterization of endothelial progenitor cells has presented new opportunities for cardiovascular research.

SUMMARY

Atherosclerosis begins in early life. Primary prevention strategies for adult cardiovascular disease beginning in childhood have great potential as the disease process is most reversible at this stage. Several guidelines have recently been published for screening and implementation of appropriate therapeutic choices in early life.

Oxidative stress-mediated arterial dysfunction in patients with metabolic syndrome: Effect of ascorbic acid

Arterial dysfunction is a hallmark of early atherosclerosis; however, its behavior in patients with metabolic syndrome (MS) is still unclear. We investigated the role of oxidative stress on ischemia-induced flow-mediated dilatation (FMD) in patients with MS. FMD and oxidative stress, as assessed by serum levels of 8-hydroxy-2-deoxy-2-deoxyguanosine (8-OHdG), were studied in 18 MS and 30 control subjects. Thereafter, in the 18 MS patients, FMD was assessed after iv infusion of 1 g vitamin C or placebo in a randomized, double-blind, crossover design; serial blood samples were taken in peripheral circulation before and after FMD to analyze 8-OHdG. Compared to controls, MS patients had higher 8-OHdG (p<0.001) and lower FMD (p<0.001); 8-OHdG and FMD were inversely correlated (R=-0.74; p<0.01). In MS patients, placebo administration did not change FMD, whereas vitamin C significantly enhanced it (p<0.001). After placebo, ischemia-induced FMD was associated with a significant increase in 8-OHdG (p<0.001), an effect that was counteracted by vitamin C. Vitamin C infusion was associated with an inverse correlation between the changes in FMD and oxidative stress (R=-0.67; p<0.01). The present study shows that arterial dilatation is impaired and that enhanced oxidative stress may play a key role in patients with MS.

Folic acid does not improve endothelial function in obese children and adolescents

OBJECTIVE

Obese children have severe endothelial dysfunction as measured by flow-mediated dilation (FMD). We have shown that folic acid normalizes endothelial function in children with type 1 diabetes who have a similar degree of endothelial dysfunction but lower total plasma homocyst(e)ine (tHcy) and higher folate status. Our aim was to evaluate, for the first time, the effect of folate supplementation on endothelial dysfunction in obese children.

RESEARCH DESIGN AND METHODS

A total of 53 obese subjects (26 male, mean +/- SD age 13.3 +/- 2.2 years, and BMI Z score 2.29 +/- 0.25) participated in a randomized, double-blind, placebo-controlled, parallel trial of oral folic acid (5 mg/day) or placebo for 8 weeks. Before and after the intervention, we assessed endothelial function (FMD), smooth muscle function (glyceryl trinitrate-induced dilatation [GTN]), high-sensitivity C-reactive protein (hsCRP), tHcy, serum folate, red cell folate (RCF), and lipids.

RESULTS

There were no group differences at baseline. FMD did not change with the intervention (folic acid group pre- and postintervention: 6.42 +/- 5.03 and 6.56 +/- 4.79%, respectively, vs. placebo group: 5.17 +/- 3.54 and 5.79 +/- 4.26%, respectively; P = 0.6). Folate supplementation increased serum folate and RCF by 18.4 nmol/l (P < 0.001) and 240.1 nmol/l (P < 0.001), respectively, and decreased tHcy by 0.95 microl (P = 0.008). The intervention did not change GTN, hsCRP, or lipids.

CONCLUSIONS

Folic acid supplementation does not improve endothelial function in obese children without diabetes despite increasing folate status and reducing tHcy. This is in contrast to the response to folate in children with type 1 diabetes.

Obesity, metabolic syndrome, and cardiovascular disease

Early childhood overweight and obesity have alarmingly increased over the years. Adulthood obesity is a well demonstrated significant independent predictor of cardiovascular risk (CVR) and/or mortality, which predisposes to the major components of metabolic syndrome (MS). Evidence of MS in obese children has been also reported associated with biochemical and inflammatory factors that affect vascular physiologic function. Assessment of vascular function can be measured noninvasively in children allowing early detection of endothelial dysfunction and severe increase of arterial stiffness before clinical manifestations of atherosclerosis. Impairment of endothelial function related to the severity of obesity and to the degree of insulin resistance is considered as a condition that confers a premature atherogenicity status and is linked to adult conventional cardiovascular risk factors. Adipose tissue factors that interfere with insulin action and endothelial cell function have also been identified as major precursors of CVR factors. The metabolic and cardiovascular consequences of childhood obesity are well demonstrated and have a major impact on the development of atherosclerosis and lifetime CVR. The development of programs involving both diet and exercise for children with overt overweight/obesity appears to be essential to improve vascular function and metabolic disorders. Such interventions should be complemented by a primary prevention against childhood obesity.

Update on the metabolic syndrome in children

PURPOSE OF REVIEW

Provides an update on the metabolic syndrome in childhood.

RECENT FINDINGS

The metabolic syndrome is increasingly recognized among children. It is nearly exclusively encountered in overweight and obese individuals and is associated with atherosclerosis. Development and clustering of cardiovascular risk factors is influenced by many characteristics including heritable traits, prenatal and infantile influences, diet, physical activity, and socioeconomic status.

SUMMARY

Epidemiological data have become mature in this area. Efforts to design and implement systems to prevent and treat the metabolic syndrome are required.