Sympathoadrenergic and metabolic factors are involved in ambulatory blood pressure rise in childhood obesity

Geneenvironment interaction between phthalate exposure and pubertal genetic polymorphisms on blood pressure variability in children: Exploring the moderating effects of lifestyle behaviours

Phthalates (PAEs) are synthetic compounds extensively employed in consumer products. Blood pressure (BP) in children can vary, the degree of visit-to-visit BP variability (VVV) is at least partially independent of BP. The interactions between PAEs exposure, pubertal-related genetic susceptibility and lifestyles on childhood VVV are not investigated. This study utilized data from a cohort collected from Oct 2017-2020 in Xiamen, China. Seven urine PAE metabolites were measured. The long-term VVV was characterized employing the standard deviation (SD) and average real variability. We constructed a genetic risk score (GRS) of pubertal-related genes and healthy lifestyle scores. Exposed to high levels of mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) (OR=1.43, 95 %CI=1.07, 1.92) and mono-2-ethyl-5-oxohexyl phthalate (OR=1.36, 95 % CI=1.01, 1.83) was related to increased SBP-SD, and the OR for high SBP-SD related to high GRS was 1.38 (95 % CI=1.02, 1.85). Compared to participants who had low GRS and low MEHHP exposure, participants exhibiting high GRS and MEHHP levels were more likely to experience high SBP-SD (OR=2.00, P<0.05). Individuals exhibiting low GRS, low MEHHP levels, and adhering to healthy lifestyles were associated with the least probability of experiencing high SBP-SD (OR=0.31, P<0.05). Increased PAEs exposure could elevate childhood systolic VVV, and exacerbated the adverse impact of pubertal-related genetic susceptibility on the high VVV of SBP; however, healthy lifestyles might alleviate these adverse effects. Promoting healthy lifestyles and reducing PAEs exposure for preventing elevated BP variability among children is important, especially for individuals with greater genetic susceptibility to early pubertal onset. ENVIRONMENTAL IMPLICATION: Blood pressure (BP) in children can vary, as a noninvasive, inexpensive and applicable method, the extent of visit-to-visit variability (VVV) is at least partially independent of BP. The interactions between phthalates (PAEs) exposure, variants of puberty-related genes and lifestyles on VVV are not investigated. Increased childhood systolic VVV might be associated with PAEs exposure, with the associations more pronounced combined with pubertal genetic susceptibility. Yet, healthy habits could partly eliminate such adverse effects. Our study underscores the importance of advocating for healthy lifestyles and reducing exposure to PAEs, especially among individuals with high genetic susceptibility to early puberty onset.

The Secretome of Parental and Bone Metastatic Breast Cancer Elicits Distinct Effects in Human Osteoclast Activity after Activation of β2 Adrenergic Signaling

The sympathetic nervous system (SNS), particularly through the β2 adrenergic receptor (β2-AR), has been linked with breast cancer (BC) and the development of metastatic BC, specifically in the bone. Nevertheless, the potential clinical benefits of exploiting β2-AR antagonists as a treatment for BC and bone loss-associated symptoms remain controversial. In this work, we show that, when compared to control individuals, the epinephrine levels in a cohort of BC patients are augmented in both earlier and late stages of the disease. Furthermore, through a combination of proteomic profiling and functional in vitro studies with human osteoclasts and osteoblasts, we demonstrate that paracrine signaling from parental BC under β2-AR activation causes a robust decrease in human osteoclast differentiation and resorption activity, which is rescued in the presence of human osteoblasts. Conversely, metastatic bone tropic BC does not display this anti-osteoclastogenic effect. In conclusion, the observed changes in the proteomic profile of BC cells under β-AR activation that take place after metastatic dissemination, together with clinical data on epinephrine levels in BC patients, provided new insights on the sympathetic control of breast cancer and its implications on osteoclastic bone resorption.

Nocturnal non-dipping on 24-h Ambulatory Blood Pressure Monitoring in children and adolescents with obesity is associated with higher total cholesterol levels

BACKGROUND

Few studies indicate the occurrence of abnormal nocturnal dipping of blood pressure (BP) in 35-50% of children and adolescents with obesity. The relation between that phenomenon and metabolic complications of obesity remains unclear. To evaluate the association between disorders of glucose and lipid metabolism, and nocturnal non-dipping in pediatric patients with obesity.

METHODS

In 207 children (53.14% girls, mean age 14 (range 2-17), mean BMI Z-SCORE 4.38, range 2.07-10.74) standard 24-h Ambulatory Blood Pressure Monitoring was performed. Normal dipping was defined as a ≥ 10% decline in BP during the night.

RESULTS

There were 106 (51.21%) cases of non-dippers. The mean 24-h nocturnal systolic BP (SBP) reduction (%) was 9.9 ± 5.5. The mean 24-h nocturnal diastolic BP (DBP) reduction (%) was 15.8 ± 8.5. There was a significant correlation between BMI Z-SCORE and mean day-time SBP (r = 0.14 P = .042). There are positive correlations between 24-h heart rate (beats/min) and BMI Z-SCORE (r = 0.15, P = .027), between fasting glucose and systolic BP Z-SCORE (r = 0.17, P = .03) and between mean diastolic BP and LDL cholesterol (r = 0.23, P = .004). Total cholesterol level was significantly higher in non-dippers (4.34 vs. 3.99 mmol/L, P = .034). There were no significant differences between non-dippers and dippers regarding fasting glucose (4.6 vs. 4.8 mmol/L), 120'post load glucose (5.7 vs. 5.9 mmol/L), insulin (19 vs. 20.2 µIU/mL), HOMA-IR (2.36 vs. 2.44), LDL cholesterol (2.64 vs. 2.51 mmol/L), HDL cholesterol (1.06 vs. 1.03 mmol/L) or triglycerides (1.36 vs. 1.34 mmol/L) levels.

CONCLUSION

Nocturnal non-dipping is frequent in pediatric patients with obesity. It is associated with higher total cholesterol levels.

School-based surveillance on visit-to-visit blood pressure variability and high blood pressure in children and adolescents

BACKGROUND

The predictive importance of visit-to-visit blood pressure variability (VVV) for high blood pressure (HBP) in a pediatric population has been largely unsettled. We aimed to evaluate it based on Health Promotion Program for Children and Adolescents (HPPCA), a school-based surveillance conducted from 2012 to 2018 in Suzhou, China.

METHODS

A total of 330,618 participants had BP measurement in 2018 and ≥ 3 BP records during 2012-2017, were recruited from HPPCA. Absolute BP values (in mmHg) were converted into age-, sex- and height- normalized z-scores. VVV was expressed as standard deviation (SD), coefficient of variation (CV) or average real variability (ARV) of BP z-scores during 2012-2017. Logistic regression models were used to assess the associations between VVV and HBP in 2018.

RESULTS

In 2018, 42,554 (12.87%) subjects were defined as HBP. VVV, except for SBP-CV and DBP-CV, was significantly higher in the HBP group than normotensives group. After adjusting for covariates including mean BP values from 2012 to 2017, SBP-SD, SBP-ARV, DBP-SD and DBP-ARV, increased the risk of HBP by 5.70 [95% confidence interval (95% CI) 5.54-5.87], 4.10 (95% CI 4.01-4.20), 4.70 (95% CI 4.50-4.90) and 3.39 (95% CI 3.28-3.50) times, respectively. Notably, SBP-SD significantly improved risk discrimination of HBP based on other risk variables (c-statistics, net reclassification index and integrated discrimination improvement significantly increased).

CONCLUSIONS

Higher SD or ARV of BP, was independently related with higher probability of HBP in Chinese pediatric population. SBP-SD could be potentially helpful for detecting HBP. Future researches investigating the predictive value of VVV are warrant.

Diagnosis and Management of Endocrine Hypertension in Children and Adolescents

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

The relationship between body fat ratio and blood pressure in school-age children

Hypertension (HTN) and obesity prevalences are rising in childhood and it is important to evaluate associations of these situations. The objective of this study is to investigate the relationship between HTN and body fat ratios (BFR) in children. This cross-sectional study was conducted among 134 participants who were directed to pediatric nephrology outpatient clinic with the prediagnosis of primary HTN. Weight, height, body fat ratio, blood pressure, and ambulatory blood pressure monitor (ABPM) was carried out for all the participants. Of the participants, 70 of them were diagnosed as hypertension with ABPM and included in the patient group, 64 of them had elevated office blood pressure (BP) but normotensive according to ABPM were included in the control group. Body fat ratio (BFR) levels of the patient group were higher than the control group (p < 0.05). There were significant linear correlation between night systolic blood pressure (SBP), night diastolic blood pressure (DBP), night mean arterial pressure (MAP), and BFR in the patient group (p < 0.05). There was a negative correlation between BFR and dipper (p = 0.022; p < 0.05) in the patient group. There was no correlation between BFR and blood pressures or dipper in the control group. According to our results BFR levels have significant association with HTN. According to our findings high BFR especially effects night BP, pulses, nondipping, and nighttime values can be evaluated only with ABPM. For prevention of HTN in children, caution should be given to monitor and lower BFR values.

Associations of plasma uric acid and purine metabolites with blood pressure in children: the KOALA Birth Cohort Study

OBJECTIVE

Elevated serum uric acid concentration has been associated with high blood pressure (BP) and hypertension. A putative underlying mechanism is the accumulation of reactive oxygen species when uric acid is generated by an increased enzyme activity of xanthine oxidase (XO). The aims of the present study were to investigate the associations between plasma uric acid concentration, purine metabolite ratios, as proxies for increased XO activity, and SBP and DBP in school-age children.

METHODS

Cross-sectional analyses were performed in 246 children (46% boys; mean age 7.1 years) from the Dutch KOALA Birth Cohort Study. Purine metabolites were determined with ultra-performance liquid chromatography-tandem mass spectrometry. During a home visit, a nurse collected a blood sample and measured BP three times; in addition, parents measured their child's BP on three consecutive days, in the morning and evening. Generalized estimating equations were used for analyses while controlling for variables such as sex, age, BMI, physical activity, and dietary intake.

RESULTS

In multivariable analysis, uric acid (per SD of 38 μmol/l) was associated with DBP z-scores [sβ 0.07; confidence interval (CI), 0.01-1.14], but not with SBP z-scores. Higher ratios of uric acid/xanthine (per SD of 138) (sβ 0.09; CI, 0.01-0.17) and xanthine/hypoxanthine (per SD of 321) (sβ 0.08; CI, 0.02-0.17) were associated with higher DBP z-scores, but not with SBP z-scores.

CONCLUSION

In school-age children, uric acid and the ratios of uric acid/xanthine and xanthine/hypoxanthine were significantly associated with DBP z-scores. Suggesting that, both uric acid concentration and increased XO activity are associated with BP.

Pathophysiology of hypertension in obese children: a systematic review

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

Metabolic syndrome: a sympathetic disease?

Metabolic syndrome is associated with adverse health outcomes and is a growing problem worldwide. Although efforts to harmonise the definition of metabolic syndrome have helped to better understand the prevalence and the adverse outcomes associated with the disorder on a global scale, the mechanisms underpinning the metabolic changes that define it are incompletely understood. Accumulating evidence from laboratory and human studies suggests that activation of the sympathetic nervous system has an important role in metabolic syndrome. Indeed, treatment strategies commonly recommended for patients with metabolic syndrome, such as diet and exercise to induce weight loss, are associated with sympathetic inhibition. Pharmacological and device-based approaches to target activation of the sympathetic nervous system directly are available and have provided evidence to support the important part played by sympathetic regulation, particularly for blood pressure and glucose control. Preliminary evidence is encouraging, but whether therapeutically targeting sympathetic overactivity could help to prevent metabolic syndrome and attenuate its adverse outcomes remains to be determined.

Cardiovascular complications of type 2 diabetes in youth

The prevalence of type 2 diabetes mellitus (T2DM) in youth has increased dramatically over the past decades. The literature also suggests that the progression from an impaired glucose tolerance state to established T2DM is more rapid in youth, compared to adults. The presence of significant cardiovascular complications in youth with T2DM, including cardiac, macrovascular, and microvascular remodeling, is another major issue in this younger cohort and poses a significant threat to the healthcare system. However, this issue is only now emerging as a major public health concern, with few data to support optimal treatment targets and strategies to reduce cardiovascular disease (CVD) risk in youth with T2DM. Accordingly, the purpose of this minireview is to better understand the cardiovascular complications in youth with T2DM. We briefly describe the pathophysiology from youth studies, including oxidative stress, inflammation, renin-angiotensin aldosterone system, and epigenetics, which link T2DM and CVD. We also describe the literature concerning the early signs of CVD in youth and potential treatment options to reduce cardiovascular risk.

Autonomic nervous system dysregulation in pediatric hypertension

Historically, primary hypertension (HTN) has been prevalent typically in adults. Recent data however, suggests an increasing number of children diagnosed with primary HTN, mainly in the setting of obesity. One of the factors considered in the etiology of HTN is the autonomous nervous system, namely its dysregulation. In the past, the sympathetic nervous system (SNS) was regarded as a system engaged mostly in buffering major acute changes in blood pressure (BP), in response to physical and emotional stressors. Recent evidence suggests that the SNS plays a much broader role in the regulation of BP, including the development and maintenance of sustained HTN by a chronically elevated central sympathetic tone in adults and children with central/visceral obesity. Consequently, attempts have been made to reduce the SNS hyperactivity, in order to intervene early in the course of the disease and prevent HTN-related complications later in life.

Obese children and adolescents have elevated nighttime blood pressure independent of insulin resistance and arterial stiffness

BACKGROUND

Insulin resistance has been related to elevated blood pressure (BP) in obese children and may adversely affect the vasculature by arterial stiffening. The objective was to investigate whether daytime and nighttime BP were elevated and related to insulin resistance and arterial stiffness in obese children and adolescents.

METHODS

Ninety-two obese patients aged 10-18 years were compared with 49 healthy control individuals. Insulin resistance was measured as the homeostatic assessment model (HOMA), and arterial stiffness was measured as carotid-femoral pulse wave velocity (cfPWV).

RESULTS

Mean ± SD daytime systolic BP (SBP) (obese: 125±8.3mm Hg; control: 121±10.1mm Hg; P = 0.03) and nighttime SBP (obese: 108±10.7mm Hg; control: 102±8.2mm Hg; P = 0.0001) were higher in the obese group when compared with the control group. No difference was found in daytime diastolic BP (DBP), whereas nighttime DBP (obese: 60±6.6mm Hg; control: 57±4.8mm Hg; P = 0.001) and night-to-day BP ratios were higher in the obese group. Nighttime SBP was related to BMI z score (β = 6.0; 95% confidence interval (CI) = 2.9-9.1; P = 0.0002) and waist/height ratio (β = 36.7; 95% CI = 5.6-67.9; P = 0.02) in the obese group. HOMA index (obese: median = 3.7, interquartile range (IQR) = 2.3-6.0; control: median = 2.6, IQR = 1.8-3.4; P = 0.002) was higher, whereas cfPWV (obese: 4.8±0.8 m/s; control: 5.1±0.6 m/s; P = 0.03) was lower in the obese group. CfPWV was not related to logHOMA index. In multiple regression analyses, the higher nighttime BP in the obese group was independent of logHOMA and cfPWV.

CONCLUSIONS

Obese children had a higher nighttime BP when compared with the control group independently of insulin resistance and arterial stiffness. No relationship was found between insulin resistance and arterial stiffness. CLINICAL TRIAL REGISTRATION Clinicaltrials.gov identifier NCT01310088.

Association between nocturnal blood pressure dipping and insulin resistance in children affected by NAFLD

The aim of this study was to analyse the relationship between insulin-glucose metabolism, nocturnal blood pressure dipping and nonalcoholic fatty liver disease (NAFLD) in obese adolescents without diabetes. One hundred one consecutive children, with biopsy-proven NAFLD, were included in this study. Blood samples were drawn for the analyses of liver function tests, insulin-glucose metabolism and lipid profile appraisal. An ambulatory blood pressure measurement (ABPM) was performed. Seventy-six children (75.3 %) were systolic nondippers, and 23 of them were diastolic nondippers (30.3 %). No differences were found in the anthropometric parameters between the two groups. When compared to the systolic dippers, the systolic nondippers had higher medians of mean nocturnal blood pressure, glucose at 0, 60 and 120 min in the oral glucose tolerance test (OGTT), OGTT insulin at all time points and insulin-resistance values. No correlation of histopathological features with dipping/nondipping statuses was found.

CONCLUSIONS

We found an association between a nocturnal blood pressure fall and measures of insulin levels, independent of obesity, or daytime blood pressure levels, among the obese patients with NAFLD. Although no association between nondipping profiles and NAFLD was observed in our study, further studies with a longer term follow-up are needed, to better elucidate the complex link between these particular entities.

Chemoreceptors, baroreceptors, and autonomic deregulation in children with obstructive sleep apnea

Obstructive sleep apnea (OSA) is highly prevalent sleep disorder of breathing in both adults and children that is fraught with substantial cardiovascular morbidities, the latter being attributable to a complex interplay between intermittent hypoxia (IH), episodic hypercapnia, recurrent large intra-thoracic pressure swings, and sleep disruption. Alterations in autonomic nervous system function could underlie the perturbations in cardiovascular, neurocognitive, immune, endocrine and metabolic functions that affect many of the patients suffering from OSA. Although these issues have received substantial attention in adults, the same has thus far failed to occur in children, creating a quasi misperception that children are protected. Here, we provide a critical overview of the evidence supporting the presence of autonomic nervous system (ANS) perturbations in children with OSA, draw some parallel assessments to known mechanisms in rodents and adult humans, particularly, peripheral and central chemoreceptor and baroreceptor pathways, and suggest future research directions.

Prevalence of persistent prehypertension in adolescents

OBJECTIVE

To measure the prevalence of persistent prehypertension in adolescents.

STUDY DESIGN

We collected demographic and anthropometric data and 4 oscillometric blood pressure (BP) measurements on 1020 students. The mean of the second, third, and fourth BP measurements determined each student's BP status per visit, with up to 3 total visits. Final BP status was classified as normal (BP <90th percentile and 120/80 mm Hg at the first visit), variable (BP ≥ 90th percentile or 120/80 mm Hg at the first visit and subsequently normal), abnormal (BP ≥ 90th percentile or 120/80 mm Hg at 3 visits but not hypertensive), or hypertensive (BP ≥ 95th percentile at 3 visits). The abnormal group included those with persistent prehypertension (BP ≥ 90th percentile or 120/80 mm Hg and <95th percentile on 3 visits). Statistical analysis allowed for comparison of groups and identification of characteristics associated with final BP classification.

RESULTS

Of 1010 students analyzed, 71.1% were classified as normal, 15.0% as variable, 11.5% as abnormal, and 2.5% as hypertensive. The prevalence of persistent prehypertension was 4.0%. Obesity similarly affected the odds for variable BP (OR, 3.9; 95% CI, 2.5-6.0) and abnormal BP (OR, 3.4; 95% CI, 2.0-5.9), and dramatically increased the odds for hypertension (OR, 38.4; 95% CI, 9.4-156.6).

CONCLUSION

Almost 30% of the students had at least one elevated BP measurement significantly influenced by obesity. Treating obesity may be essential to preventing prehypertension and/or hypertension.

Impact of obesity on childhood kidney

Obese patients are known to have greater risks to develop hypertension, coronary vascular disease, and insulin resistance, and more attention has been recently paid to the impact of obesity on kidney. This study was conducted to investigate whether obese children have higher risk of renal injury as well as adults. Eighteen hundred and thirty school children aged 6-14 years with abnormal urinary findings on thrice occasions detected by the screening program for renal disease in Japan were enrolled. Of them, 27 children with nephritis or suspected nephritis diagnosed by persistent proteinuria with hematuria were compared to 588 without urinary abnormalities regarding their body mass index (BMI), blood pressure (BP), and serum level of total cholesterol. BMI and systolic BP (mmHg) were significantly higher in the former than in the latter. As a result, obesity may be associated with the development of renal injury even in childhood.

Relationship between cardiovascular risk factors and adipokines in adolescents

This study evaluated the associations of adipokines with cardiovascular risk factors.

SUBJECTS/METHODS

60 normal weight (BMI ≤75th percentile) and 60 overweight (BMI ≥95th percentile) adolescents aged 10-14 years. Resting systolic and diastolic blood pressures (SBP, DBP) and waist circumference were obtained in duplicate. Circulating adiponectin, resistin, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), total cholesterol (TC), high-density lipoprotein (HDL), and triglycerides (TG) were measured from fasting plasma samples.

RESULTS

Simple correlations showed that SBP was significantly related (p < 0.05) to adiponectin (r = -0.185), resistin (r = 0.207), and IL-6 (r = 0.238); HDL was significantly related to adiponectin (r = 0.398) and TNF-α (r = -0.227). TG was only related to adiponectin (r = -0.292, p < 0.05). Multiple regression models controlling for puberty and ethnicity indicated that adiponectin (R(2) = 0.152, p < 0.05), resistin (R(2) = 0.152, p < 0.05), and IL-6 (R(2) = 0.170, p < 0.05) were associated with SBP. The association between adiponectin and HDL was stronger in normal weight versus overweight adolescents (R(2) = 0.336, p < 0.05). None of the other models showed differences in the associations by weight status.

CONCLUSIONS

In adolescents, SBP but not DBP was associated with most adipokines. HDL, but not TC, was also associated with some adipokines. TG were only associated with adiponectin. Associations were mostly related to adiposity.

Long-term follow-up of cardiovascular risk factors after exercise training in obese children

OBJECTIVE

We previously demonstrated beneficial effects of physical activity on cardiovascular disease (CVD) risk factors, body mass index (BMI) and fat mass in pre-pubescent obese children. The aim of this study was to determine whether these changes were maintained 2 years later.

METHODS

Two years after the Randomised Controlled Trial, we performed a follow-up study with 20 of 38 subjects (11.4 ± 1.8 years). Outcomes included blood pressure (BP) by ambulatory monitoring; arterial function and structure using high-resolution ultrasound, BMI, body composition by dual-energy x-ray absorptiometry (DXA), physical activity using accelerometer, and biological markers.

RESULTS

During the 2-year follow-up period, mean 24-hour diastolic BP z-score significantly decreased (1.4 ± 1.2 vs. 0.3 ± 1.4, p = 0.04), while systolic BP z-score was slightly reduced (2.4 ± 1.5 vs. 1.4 ± 1.7, p = 0.067). Blood pressure changes were greater in children who diminished their BMI z-score compared with the ones who did not. Systolic hypertension rates dropped from 50 to 28% and diastolic hypertension from 42 to 6%. In addition, arterial intima-media thickness (0.51 ± 0.03 vs. 0.51 ± 0.06, p = 0.79), BMI z-score (2.9 ± 0.8 vs. 2.9 ± 1.1 kg.cm(-2), p = 0.27), body fat (41.9 ± 6.9 vs. 42.8 ± 6.7%; p = 0.39) and physical activity count (703 ± 209 vs. 574 ± 244 cpm, p = 0.30) were stable.

CONCLUSION

To our knowledge, this is the first study reporting that beneficial effects on adiposity and CVD risk factors of a physical activity centred intervention are sustained 2 years after the cessation of training in obese children. Subjects stabilized BMI z-score and maintained physical activity with further improvement of BP and stabilization of arterial wall remodelling. We conclude that it is important to encourage physical activity in this population. Effects of Aerobic Exercise Training on Arterial Function and Insulin Resistance Syndrome in Obese Children: A Randomised Controlled Trial: NCT00801645.

Trends in blood pressure and hypertension among Chinese children and adolescents: China Health and Nutrition Surveys 1991-2004

OBJECTIVE

To observe the trends in blood pressure (BP) and prevalence of hypertension among Chinese children and adolescents.

METHODS

Data were extracted from the China Health and Nutrition Survey conducted from 1991 to 2004; 8247 children and adolescents aged 6-17 years were selected for this study. Multivariate linear regression analysis and multivariate logistic regression analysis were performed to evaluate the secular trends in BP levels and prevalence of hypertension, respectively.

RESULTS

During the study period, there was an upward trend in BP in Chinese children and adolescents. After adjustment for gender, age and weight status, the prevalence of pre-hypertension and hypertension increased dramatically from 1991 to 2004, with average relative increases of 6.38% and 8.13% in children and adolescents, respectively. Overweight was strongly associated with pre-hypertension and hypertension in comparison with normal weight, with odds ratios (95% confidence intervals) of 2.21 (1.58-3.11) and 4.13 (3.32-5.13), respectively.

CONCLUSION

BP levels and prevalence of hypertension increased dramatically among Chinese children and adolescents from 1991 to 2004.

Association of polycystic ovary syndrome and a non-dipping blood pressure pattern in young women

OBJECTIVE

The association between polycystic ovarian syndrome and increased cardiovascular disease risk is still a controversial issue. In light of data documenting some common pathways or common end-points, the present study was undertaken to determine whether there is a relationship between sleep blood pressure pattern disturbances and polycystic ovarian syndrome in young women.

METHOD

The daytime and nighttime ambulatory blood pressures (BPs) were determined for each subject, according to the actual waking and sleeping times recorded in their individual diaries, in this cross-sectional study.

RESULTS

The study group comprised 168 women (mean age: 25.7+/-5.5) diagnosed with polycystic ovarian syndrome, while the control group included 52 age- and BMI-matched healthy subjects (mean age: 26.1+/-5.4). When nocturnal BP declines very little or not at all, with the BP falling less than 10% during sleep compared with waking values, this pattern is classified as a non-dipping BP pattern. However, the non-dipping pattern of BP changes was significantly more common in polycystic ovarian syndrome patients compared to the control group (p<0.01). The prevalence of a non-dipping BP pattern was 43.4% (73 patients) in polycystic ovarian syndrome patients and 3.9% (2 patients) in the control group.

CONCLUSION

Our cross-sectional study revealed that a non-dipping BP pattern is highly prevalent in polycystic ovarian syndrome patients, even if they are young and non-obese.

Association of current weight and birth weight with blood pressure levels in Saharan and European teenager populations

BACKGROUND

The Saharan adult population is characterized by a high prevalence of hypertension. The aim of the present study was to compare blood pressure (BP) levels in Saharan Arab-origin teenagers, in relationship with Europeans of the same age, and to assess the association with birth weight, body weight, and other anthropometric measurements.

METHODS

BP values, heart rate (HR), clinical parameters, and anthropometric measurements were determined in 2,057 teenagers ages 15-19, 1,122 Algerians (388 boys) and 935 Italians (407 boys). Birth weight was obtained from obstetrical records in 568 Algerians and 735 Italians.

RESULTS

The European teenagers were significantly taller and heavier than their Algerian counterparts. In the Algerian population, systolic BP (SBP) was higher in boys (P < 0.01) and lower in girls (P < 0.0001) compared to the Italians, whereas diastolic BP (DBP) was higher in Italians (P < 0.001). Both SBP and DBP were higher in boys than in girls independently of geographic origin (P < 0.001). In all four gender and ethnic groups, both SBP and DBP were strongly correlated with weight or body mass index (BMI). Influence of body weight was stronger on SBP than on DBP; in all four groups, those with the highest weight or BMI quartiles had higher SBP levels by 6-12 mm Hg as compared to those individuals in the lowest quartiles. No correlation was found between birth weight, and SBP or DBP.

CONCLUSIONS

In Algerian and Italian teenagers, both male and female, current weight but not birth weight was found to be a strong determinant of BP levels.

Altered cardiovascular rhythmicity in children with white coat and ambulatory hypertension

Adults with ambulatory hypertension or white coat hypertension (WCH) display abnormal cardiovascular rhythms. We studied cardiovascular rhythms by Fourier analysis of 24-h ambulatory blood pressure (BP) measurement profiles in 129 hypertensive children, 54 children with WCH, and 146 age-, height-, and gender-matched healthy subjects. The day/night mean arterial pressure ratio was lower in hypertensive and patients with WCH compared with controls (1.13 versus 1.16 versus 1.21, respectively; p < 0.0001). Eighty-five percent of controls were dippers compared with 74% of WCH (n.s.) and 64% of patients with ambulatory hypertension (p < 0.0001). The prevalence of 24-h rhythms was similar among the groups, but prevalence of 12-h BP rhythms was increased in hypertensive (67%) and WCH (72%) compared with controls (51%, p < 0.0001). The amplitudes of the 24-, 8-, and 6-h BP rhythms were reduced in hypertensive and WCH compared with controls (p < 0.05). Hypertensive and patients with WCH displayed delayed 24-, 12-, 8-, 6-h acrophases in comparison with controls (p < 0.05). In conclusion, hypertensive children exhibit abnormal cardiovascular rhythmicity compared with controls, especially a higher prevalence of nondipping compared with normotensive children. Abnormalities in patients with WCH are intermediate between healthy children and patients with ambulatory hypertension.

Markers of inflammation and hemodynamic measurements in obesity: Copenhagen City Heart Study

BACKGROUND

Low-grade chronic inflammation has been proposed to play a major role in the pathogenesis of hypertension. Low-grade chronic inflammation is also closely associated with obesity, an established causative factor in the development of hypertension. The purpose of this study was to investigate the relationship between two markers of inflammation, C-reactive protein (CRP) and fibrinogen, and blood pressure (BP) and other hemodynamic variables in obese subjects.

METHODS

From a large cardiovascular study based in the general population, we selected subjects with a body mass index (BMI) > or =30 kg/m2, free of major cardiovascular diseases, not taking BP-lowering or lipid-lowering drugs (n = 487; women = 51.1%; median (5th to 95th percentile) age = 62 years (36-80)). The cardiovascular study included measurements of traditional and new risk factors, including ankle brachial BP index, a measure of subclinical atherosclerosis. CRP was determined by a high-sensitive assay.

RESULTS

In partial Spearman rank correlation analysis, adjusted for age and sex, we found no significant relationships between either CRP or fibrinogen and systolic BP, diastolic BP, pulse pressure, or ankle brachial index (rho: -0.057 to 0.068; P > 0.13). However, fibrinogen and CRP were found to be significantly related to heart rate (rho: 0.127-0.169; P < 0.01).

CONCLUSIONS

In this study of generally healthy obese subjects from the general population, we found no significant relationships between markers of inflammation and systolic BP or diastolic BP, showing that obese subjects with higher levels of inflammatory markers do not have higher BP levels than their obese counterparts with lower levels of inflammatory markers.

Canonical transient receptor potential channels expression is elevated in a porcine model of metabolic syndrome

Plasma epinephrine and heart rate are elevated in metabolic syndrome, suggesting enhanced catecholamine secretion from the adrenal medulla. Canonical transient receptor potential (TRPC) channels are implicated in mediating hormone-induced Ca(2+) influx and catecholamine secretion in adrenomedullary chromaffin cells. We studied the pattern of TRPC expression in the pig adrenal medulla and investigated whether adrenal TRPC expression is altered in prediabetic metabolic syndrome Ossabaw miniature pigs. We used a combination of molecular biological, biochemical, and fluorescence imaging techniques. We determined the sequence of pig TRPC1 and TRPC3-7 channels. We found that the pig adrenal medulla expressed predominantly TRPC1, TRPC5, and TRPC6 transcripts. The expression level of these TRPCs was significantly elevated in the adrenal medulla from pigs with metabolic syndrome. Interestingly, aldosterone, which is endogenously secreted in the adjacent adrenal cortex, increased TRPC1, TRPC5, and TRPC6 expression in adrenal chromaffin cells isolated from metabolic syndrome but not control pigs. Spironolactone, a blocker of mineralocorticoid receptors, inhibited the aldosterone effect. Dexamethasone also increased TRPC5 expression in metabolic syndrome chromaffin cells. The amplitude of hormone-induced divalent cation influx correlated with the level of TRPC expression in adrenal chromaffin cells. Orai1/Stim1 protein expression was not significantly altered in the metabolic syndrome adrenal medulla when compared with the control. We propose that in metabolic syndrome, abnormally elevated adrenal TRPC expression may underlie increased plasma epinephrine and heart rate. The excess of plasma catecholamines and increased heart rate are risk factors for cardiovascular disease. Thus, TRPCs are potential therapeutic targets in the fight against cardiovascular disease.