The role of obesity in the pathogenesis of hypertension

Adiposity indices and their higher predictive value for new-onset hypertension in metabolically healthy young women: findings from a population-based prospective cohort study

BACKGROUND AND AIMS

The present study aimed to investigate the predictive ability of selected adiposity indices, such as body mass index (BMI), waist-to-hip ratio (WHR), waist circumference (WC), and waist-to-height ratio (WHtR), for new-onset hypertension in metabolically healthy Taiwanese adults. The study also sought to establish sex-specific cutoff points for these indices and to analyze the risk of new-onset hypertension, taking into account sex and age.

METHODS

This prospective cohort study utilized the Taiwan Biobank database to examine metabolically healthy participants aged between 20 and 65 at baseline. Four adiposity indices, namely BMI, WHR, WC, and WHtR, were calculated and used to predict new-onset hypertension over 4 years. Receiver operating characteristics (ROCs) and areas under the curve (AUCs) were used to evaluate the effectiveness of the parameters in predicting new-onset hypertension over 4 years. Sex-specific cutoff points were identified and used to assess the risk of new-onset hypertension.

RESULTS

This study analyzed 13,375 participants over 4.28 years. The incidence of new-onset hypertension was 17.65%. The new-onset rate of hypertension was 34.39% in men and 65.61% in women. Adiposity indices effectively predict new-onset hypertension, with WHtR having the highest predictive value (i.e., AUC) for both sexes. The classification of participants into low and high categories for each adiposity index was based on sex-specific cutoff points, and the risk of new-onset hypertension was assessed according to sex and age. This study found that high adiposity indices predicted a significantly higher risk of new-onset hypertension in metabolically healthy adults. The risk was equal for both sexes. Young women had a higher risk of new-onset hypertension than middle-aged women when they were further categorized. All risk ratios of the indices in young women were over two-fold and significant.

CONCLUSION

According to the sex-specific cutoff point, high adiposity indices had a higher predictive value for new-onset hypertension in metabolically healthy Taiwanese young women.

Mediating effect of cumulative lipid profile burden on the effect of diet and obesity on hypertension incidence: a cohort study of people aged 35-65 in rural China

BACKGROUND AND OBJECTIVES

Cumulative lipid profile burden is designed to dynamically measure lipid accumulation, and its effect on hypertension has been poorly studied. Our main purpose was to investigate the effect of cumulative lipid profile burden on the incidence of essential hypertension (EH) and to investigate whether cumulative lipid burden mediates the pathogenesis of the effects of diet and obesity on EH.

SUBJECTS AND METHODS

A total of 1295 participants were included in the study, which started in 2017. The average follow-up time was 2.98 years. A total of 240 EH patients occurred during the follow-up period.

RESULTS

The HR (95% CI) of the highest quartile in cumulative Total cholesterol (TC), triglyceride (TG) and high density lipoprotein (HDL) burden were 1.747 (1.145 - 2.664), 1.502 (1.038 - 2.173), 0.615 (0.413 - 0.917) for incidence of EH respectively, compared to the respective reference groups. Participants with EH consumed more red meat and refined grains, and red meat was positively associated with cumulative TC burden. BMI and Waist-To-Height Ratio (WHtR) increased the incidence of EH, and obesity was positively correlated with cumulative TG burden. Mediating analysis showed that cumulative TG had a partial mediating effect in the causal relationship between obesity and EH, and Mendelian randomization (MR) also proved this result. Diet was not found to influence EHn through cumulative lipid profile burden.

CONCLUSIONS

The cumulative TG burden partially mediates the effect of obesity on EH.

Prevalence of high blood pressure and its associated factors among students in Shenyang, China: A cross-sectional study

There is growing evidence that the prevalence of high blood pressure is increasing, and it may have serious consequences. However, research on the prevalence and influencing factors of high blood pressure among primary and secondary school students is still relatively scarce. This study aims to investigate the prevalence and influencing factors of high blood pressure among primary and secondary school students in Shenyang, in order to provide scientific evidence for the prevention and management of this disease. From April to May 2020, 4892 students aged 7 to 17 years were selected as the survey subjects, and on-site physical measurements and questionnaire surveys were conducted. The prevalence of high blood pressure was described. Restricted cubic spline was used to analyze the dose-response relationship between sleep duration, BMI and the risk of high blood pressure. Logistic regression was used to analyze the risk factors. Multiplicative and additive models were used to analyze the interaction between sleep duration and BMI. The results showed that the overall prevalence of high blood pressure among students aged 7 to 17 years in Shenyang was 9.9%, with a higher prevalence in females than males (12.1% vs 7.9%) and in urban areas than suburban areas (11.8% vs 7.7%). The prevalence was lowest in students with normal weight (8.3%) and highest in those who were obese (12.5%). The prevalence fluctuated to some extent among different age groups, but overall, it increased with age, with the lowest prevalence in primary school students (7.0%), 11.4% in mild school students, and the highest prevalence of 14.3% in high school students. Multivariable analysis showed that the risk of high blood pressure in female students was 1.90 times higher than that in male students (95% CI: 1.54-2.35), and the risk in suburban areas was 0.65 times lower than that in urban areas (95% CI: 0.52-0.81). Students with a BMI ≥ 21 kg/m2 had a 1.58 times higher risk than those with a BMI < 21 kg/m2(95% CI: 1.28-1.96), while those with a sleep time ≥ 8 hours had a 0.80 times lower risk than those with a sleep time < 8 hours (95% CI: 0.65-0.99). Exercise can significantly reduce the risk of high blood pressure, while using electronic devices for more than 0.5 hours significantly increases the risk of high blood pressure. BMI and sleep duration have no interaction effect on the risk of high blood pressure. To reduce the prevalence of high blood pressure, students should reduce the use of electronic devices, ensure adequate exercise, maintain a reasonable weight, and ensure sufficient sleep.

Incidence of Arterial Hypertension is Associated with Adiposity in Children and Adolescents

BACKGROUND

The increase of hypertension in children and adolescents has attracted the attention of the scientific community largely due to its association with the obesity epidemic.

OBJECTIVES

To describe the incidence of hypertension and its relationship with the cardiometabolic and genetic profile in children and adolescents from a city in southern Brazil in a three-year period.

METHODS

This longitudinal study followed 469 children and adolescents, aged 7-17 years old (43.1% boys), assessed at two-time points. We evaluated systolic and diastolic blood pressures (SBP and DBP), waist circumference (WC), body mass index (BMI), body fat percentage (%BF), lipid profile, glucose, cardiorespiratory fitness (CRF), and rs9939609 Polymorphism ( FTO ). Cumulative incidence of hypertension was calculated, and multinomial logistic regression was conducted. The statistical significance was established as p < 0.05.

RESULTS

After three years, the incidence of hypertension was 11.5%. Overweight or obese individuals were more likely to become borderline hypertensive (overweight OR: 3.22, 95% CI: 1.08-9.55; obesity OR: 4.05, 95% CI: 1.68-9.75), and obese individuals were more likely to become hypertensive (obesity OR: 4.84, 95% CI: 1.57-14.95). High-risk WC and %BF values were associated with hypertension development (OR: 3.41, 95% CI: 1.26-9.19; OR: 2.49, 95% CI: 1.08-5.75, respectively).

CONCLUSIONS

We found a higher incidence of hypertension in children and adolescents as compared with previous studies. Individuals with higher values of BMI, WC and %BF at baseline were more likely to develop hypertension, suggesting the importance of adiposity in the development of hypertension even in such a young population.

Multimorbidity and obesity in older adults from six low- and middle-income countries

Prevalence of multimorbidity (i.e., ≥2 chronic conditions), chronic diseases, and obesity is increasing in low- and middle-income countries (LMICs), posing a potential threat to the health of older adults living in these areas. This study hence investigates the unexplored association between obesity and multimorbidity among older adults from LMICs. Cross-sectional, community-based data from the WHO Study on global Ageing and adult health (SAGE) were analysed. The sample consisted of 20,198 individuals aged ≥60 years [Mean age (SD) = 69.3 (13.1) years; 54.1% female] from China, India, Ghana, Mexico, Russia, South Africa. Twelve chronic conditions were assessed. Multivariable logistic regression was conducted to assess the association between BMI ≥ 30 kg/m², high waist circumference (WC, cut-points > 102 cm for males and > 88 cm for females) and multimorbidity. After adjusting for potential confounders, overall, BMI ≥ 30 kg/m² was associated with 1.43 (95%CI = 1.21-1.69) times higher odds for multimorbidity, while this estimate for high WC was 1.50 (95%CI = 1.21-1.86). Significant associations emerged between obesity measures and five out of twelve chronic conditions. Results from this study underline the need to reduce obesity among older adults in areas where its prevalence is increasing, as it is associated with increased odds for multimorbidity. Future longitudinal research in this setting is required to assess the impact of obesity reduction on multimorbidity incidence.

Plasma Adiponectin and Blood Pressure Progression in African Americans: The Jackson Heart Study

BACKGROUND

Little is known on the association of plasma adiponectin with blood pressure (BP) changes in African Americans (AAs). We evaluated the associations between plasma adiponectin and BP progression among AAs.

METHODS

We analyzed data from 1,184 participants without hypertension at baseline (2000-2004) with ≥1 follow-up visits in the Jackson Heart Study. We used robust Poisson regression to generate risk ratios (RRs) for BP progression (an increase by ≥1 BP stage) and incident hypertension.

RESULTS

Over a median of 7 years, 71% progressed to higher BP stage and 65% developed hypertension. We found evidence of interaction by sex (P-interaction = 0.088). Compared with those in the lowest quartile (Q1), male participants in the highest adiponectin quartile (Q4) had reduced risks of BP progression (RR 0.76 [95% confidence interval, CI, 0.60-0.96]) and incident hypertension (RR 0.74 [95% CI 0.56-0.97]). After accounting for body mass index, this relation persisted among obese men (RR for the highest [vs. lowest] adiponectin quartile: 0.59 [95% CI 0.36-0.97] for incident hypertension, and 0.69 [95% CI 0.45-1.06] for BP progression). Among women, adiponectin was not associated with BP outcomes (RR [95% CI] for Q4 vs. Q1: 1.03 [0.86-1.23] and 1.01 [0.83-1.23] for BP progression and incident hypertension, respectively). Our findings were consistent across both the American College of Cardiology (ACC)/American Heart Association (AHA) and Seventh Joint National Committee (JNC-7) BP categories.

CONCLUSIONS

In a large, community-based sample of AAs, higher adiponectin concentrations were associated with lower risks of BP progression and incident hypertension in men, but no significant association was observed in women.

AdipoRon Attenuates Hypertension-Induced Epithelial-Mesenchymal Transition and Renal Fibrosis via Promoting Epithelial Autophagy

Hypertension-induced epithelial-mesenchymal transition (EMT) is a major mechanism of renal fibrosis. Adiponectin protects against hypertension-induced target organ damage. AdipoRon is an orally active synthetic adiponectin receptor agonist. However, it is unclear whether AdipoRon could attenuate EMT and renal fibrosis in hypertensive mice. C57BJ/6J mice were utilized to induce DOCA-salt-sensitive hypertensive model. Hypertension results in an altered adiponectin expression and promotes EMT in the kidney. In vitro, AdipoRon inhibits aldosterone (Aldo)-induced EMT and promotes autophagic flux in HK-2 epithelial cells. Mechanically, AdipoRon activates AMPK/ULK1 pathway in epithelial cells. Blockade of AMPK activation, as well as inhibition of autophagy, blocks the effects of AdipoRon on Aldo-induced EMT. Moreover, AdipoRon treatment promotes autophagy and improves renal fibrosis in DOCA-salt-hypertensive mice. Our data suggest that AdipoRon could be a potential therapeutic option to prevent renal fibrosis in hypertensive patients. Graphical abstract.

Plasma Leptin and Blood Pressure Progression in Blacks: The Jackson Heart Study

[Figure: see text].

In Vivo Magnetic Resonance Imaging-Based Detection of Heterogeneous Endothelial Response in Thoracic and Abdominal Aorta to Short-Term High-Fat Diet Ascribed to Differences in Perivascular Adipose Tissue in Mice

Background Long-term feeding with a high-fat diet (HFD) induces endothelial dysfunction in mice, but early HFD-induced effects on endothelium have not been well characterized. Methods and Results Using an magnetic resonance imaging-based methodology that allows characterization of endothelial function in vivo, we demonstrated that short-term (2 weeks) feeding with a HFD to C57BL/6 mice or to E3L.CETP mice resulted in the impairment of acetylcholine-induced response in the abdominal aorta (AA), whereas, in the thoracic aorta (TA), the acetylcholine-induced response was largely preserved. Similarly, HFD resulted in arterial stiffness in the AA, but not in the TA. The difference in HFD-induced response was ascribed to distinct characteristics of perivascular adipose tissue in the TA and AA, related to brown- and white-like adipose tissue, respectively, as assessed by histology, immunohistochemistry, and Raman spectroscopy. In contrast, short-term HFD-induced endothelial dysfunction could not be linked to systemic insulin resistance, changes in plasma concentration of nitrite, or concentration of biomarkers of glycocalyx disruption (syndecan-1 and endocan), endothelial inflammation (soluble form of vascular cell adhesion molecule 1, soluble form of intercellular adhesion molecule 1 and soluble form of E-selectin), endothelial permeability (soluble form of fms-like tyrosine kinase 1 and angiopoietin 2), and hemostasis (tissue plasminogen activator and plasminogen activator inhibitor 1). Conclusions Short-term feeding with a HFD induces endothelial dysfunction in the AA but not in the TA, which could be ascribed to a differential response of perivascular adipose tissue to a HFD in the AA versus TA. Importantly, early endothelial dysfunction in the AA is not linked to elevation of classical systemic biomarkers of endothelial dysfunction.

A high triglyceride glucose index is more closely associated with hypertension than lipid or glycemic parameters in elderly individuals: a cross-sectional survey from the Reaction Study

Background

Both lipid and glucose abnormalities are associated with hypertension (HTN). However, it is unclear whether the triglyceride-glucose (TyG) index is associated with HTN. Therefore the aim of this study is to investigate the association of the TyG index and HTN and to compare the discriminative power of the TyG index, lipid, glycemic parameters for the risk of HTN in elderly individuals.

Methods

The present study was nested in a longitudinal (REACTION) study from May 2011 to December 2011, which was designed to demonstrate the association of abnormal glucose metabolism with the risk of cancer in the Chinese population. In total, 47,808 participants were recruited in this cross-sectional study. The TyG index was divided into five groups: the < 20% group, the 20–39% group, the 40–59% group, the 60–79% group and the ≥ 80% group, according to quintile division of the subjects. Three multivariate logistic regression models were used to evaluate the association between the TyG vs. lipid parameters, glycemic parameters and HTN.

Results

Multivariate logistic regression analysis shows that compared with lipid and glycemic parameters, the TyG index remains significantly associated with HTN in either total subjects or subjects separated into men and women (odds ratio (OR) 1.33, 95% confidence interval (CI) 1.18–1.51, p < 0.0001 in total subjects; OR 1.39, 95% CI 1.11–1.74, p = 0.0042 in men; OR 1.28, 95% CI 1.11–1.49, p = 0.0010 in women). In a stratified analysis, an elevated TyG index is significantly associated with HTN in the subgroup of the oldest age (≥ 65) (OR 1.67, 95% CI 1.30–2.14, p < 0.0001), as well as with obesity (Body mass index (BMI) ≥ 28 kg/m²) (OR 1.85, 95% CI 1.29–2.66, p = 0.0009) or lower estimated glomerular filtration rate (eGFR) (< 90 mL/(min·1.73 m²)) (OR 1.72, 95% CI 1.33–2.21, p < 0.0001).

Conclusion

The TyG index is significantly associated with HTN and shows the superior discriminative ability for HTN compared with lipid and glycemic parameters in the Chinese elderly population.

Association between duration of obesity and severity of ovarian dysfunction in rat-cafeteria diet approach

Consumption of unhealthy, energy-dense palatable food during early age leads to obesity in children and the onset of obesity during childhood has a profound effect on the reproductive health of women. In this study, the mechanism underlying diet-induced obesity on ovarian dysfunction was studied by exposing rats to cafeteria diet (CAFD) for two different durations. For that purpose, 21-day-old female Sprague Dawley rats were fed ad libitum with a standard diet (control group) and a cafeteria diet (CAFD group) for a period of 20 weeks (20 W) and 32 weeks (32 W). We observed obesity, hyperglycemia, hyperlipidemia, hyperleptinemia and hypoadiponectinemia in CAFD fed groups. Hyperinsulinemia, hypergonadotrophism, hypertestosteronemia and hyperprogesteronemia were observed in the 20 W-CAFD group. Conversely, in the 32 W-CAFD group hypersecretion declined to hyposecretion. The levels of estradiol remained low during both time periods. The duration of estrous cycle was extended in the CAFD fed rats. The ovary weight was higher in the 20 W-CAFD fed rats but it was drastically reduced over a longer duration cafeteria diet feeding. In the 20 W-CAFD fed rats, the protein levels of LHR, StAR, CYP11A1, 3β-HSD and 17β-HSD were increased but FSHR and CYP19A1 levels were decreased in the ovary. On the other hand, gonadotropin receptor and the protein levels of steroidogenic enzymes were decreased in the ovary of 32 W-CAFD fed rats. We conclude that the duration of energy-dense diet consumption has differential regulatory mechanism in altering the ovarian steroid production. In 20 W-CAFD fed rats, hypergonadotropic condition was observed whereas, 32 W-CAFD consumption induced hypogonadotropic hypogonadism.

Obesity and its cardiovascular effects

Obesity is described in terms of body fat percentage or body mass index (BMI), despite the fact that these measures do not give full insight about the body fat distribution. It is presently a consistently growing universal challenge since it has tripled in the last 10 years, killing approximately 28 million people each year. In this review, we aim to clarify the different results of obesity on the working and physiology of the cardiovascular system and to reveal changes in the obesity "paradox"-a variety of cardiovascular outcomes in typical/overweight people. Central fat build-up in ordinary/overweight populaces has been related to expanded occurrences of myocardial infarction, heart failure, or all-cause mortality when contrasted with the obese populace. These discoveries are additionally clarified as the abundance and prolonged vulnerability to free fatty acids (FFAs) in obesity. This has been believed to cause the myocardial substrate to move from glucose to FFAs digestion, which causes lipid gathering in cardiomyocytes, spilling over to other lean tissues, and prompting a general atherogenic impact. This cardiomyocyte lipid aggregation has been demonstrated to cause insulin resistance and cardiovascular hypertrophy, and to lessen the heart functions in general. There is a proof backing the fact that fat tissue is not only an energy reservoir, it also coordinates hormones and proinflammatory cytokines and deals with the energy transition of the body by putting away abundant lipids in diverse tissues.

Validity of cardiometabolic index, lipid accumulation product, and body adiposity index in predicting the risk of hypertension in Chinese population

OBJECTIVES

Adiposity, defined by higher cardiometabolic index (CMI), lipid accumulation product (LAP), and body adiposity index (BAI), has conferred increased metabolic risk. However, the incremental utility of CMI, LAP, and BAI in association with prevalent hypertension has not been well described in a population-based setting. We hypothesized that CMI, LAP, and BAI would provide important insight into hypertension risk.

METHODS

Blood pressure (BP), fasting lipid profiles, and anthropometric parameters were recorded in a cross-sectional study of 11,400 participants (mean age, 54 years; 53% women) from China. Logistic regression models were used to assess associations of CMI, LAP, and BAI with prevalent hypertension. BAI was evaluated according to hip (cm)/[height (m)^1.5]-18; LAP was calculated separately for men [(WC-65) × TG] and women [(WC-58) × TG]; and CMI was defined by TG/HDL-C × waist-to-height ratio.

RESULTS

CMI, LAP, and BAI were independently correlated with higher SBP and DBP, with nonstandardized (B) coefficients ranging from 1.827 to 4.590 mmHg and 1.475 to 2.210 mmHg (all P < 0.001). After adjustment for hypertension risk factors and potential confounders, CMI, LAP, and BAI, modeled as continuous measures, carried hypertension odds (95% CI) of 1.356 (1.259-1.459), 1.631 (1.501-1.771), and 1.555 (1.454-1.662) in women, respectively, per SD increment. In men, each SD increase in CMI, LAP, and BAI experienced a 31%, 65%, and 53% higher hypertension risk, respectively. Moreover, among women, the odds ratio (95% CI) for hypertension were 2.318 (1.956-2.745), 3.548 (2.985-4.217), and 3.004 (2.537-3.557) in the 4th quartile vs the first quartile of CMI, LAP, and BAI, respectively. For men, the corresponding figures were 2.200 (1.838-2.635), 3.892 (3.238-4.677), and 3.288 (2.754-3.927), respectively.

CONCLUSION

Measurements of CMI, LAP, and BAI provide a more complete understanding of hypertension risk related to variation in body fat distribution and pinpoint hypertensive participants in great risk of cardiovascular disease in the future.

Looking for new diagnostic tools and biomarkers of hypertension in obese pediatric patients

INTRODUCTION

Development of obesity in childhood may be linked to an increased risk of hypertension.

OBJECTIVES

This study aimed (a) to analyze the expression of genes associated with blood pressure (BP) in obese children, (b) to evaluate ambulatory blood pressure monitoring (ABPM) as a diagnostic tool in hypertension in children, and (c) to assess the prevalence of metabolic syndrome in children with obesity.

PATIENTS AND METHODS

Office BP measurements and ABPM were performed in 49 children with obesity and 25 age-matched healthy children. Expressions of 12 monogenic hypertension genes and 45 genes variants associated with BP were assessed using the microarray technique.

RESULTS

No significant differences in gene expression levels were found. Children with obesity had significantly higher (P<0.001) mean office systolic and diastolic BPs compared with the controls. The diagnosis of high normal BP and hypertension with ABPM was established in 27 and 33% of children, respectively. Nocturnal BP decrease less than 10% was found in 27% of children, whereas nocturnal BP decrease more than 20% was found in 13% of children. Nocturnal BP increase was found in 13% of patients. The diagnosis of metabolic syndrome was established in 29% of obese patients.

CONCLUSION

The following can be concluded: (a) the prevalence of metabolic syndrome was found in nearly one-third of children with obesity. (b) ABPM is a useful and reliable tool in the diagnostics of pediatric hypertension. Abnormal BP can be observed in ∼50% of obese children.

Inhibitory Effects of Siegesbeckia orientalis Extracts on Advanced Glycation End Product Formation and Key Enzymes Related to Metabolic Syndrome

Metabolic syndrome typically includes Type 2 diabetes associated with hyperglycemia, central obesity, dyslipidemia and hypertension. It is highly related to oxidative stress, formation of advanced glycated end products (AGEs) and key enzymes, such as carbohydrate digesting enzymes like pancreatic α-amylase and intestinal α-glucosidase, pancreatic lipase and angiotensin I-converting enzyme (ACE). This study used an in vitro approach to assess the potential of four extracts of Siegesbeckia orientalis linne on key enzymes relevant to metabolic syndrome. In this research, S. orientailis was firstly extracted by ethanol. The ethanol extract (SE) was then partitioned sequentially with hexane, ethyl acetate and methanol, and these extracts were named SE-Hex, SE-EA and SE-MeOH, respectively. The experimental results showed that SE-EA had the highest total phenolic content (TPC, 76.9 ± 1.8 mg/g) and the total flavonoids content (TFC, 5.3 ± 0.3 mg/g). This extract exhibited the most significant antioxidant activities, including DPPH radical-scavenging capacity (IC₅₀ = 161.8 ± 2.4 μg/mL), ABTS radical-scavenging capacity (IC₅₀ = 13.9 ± 1.5 μg/mL) and reducing power. For anti-glycation activities, SE-EA showed the best results in the inhibition of AGEs, as well as inhibitory activities against α-glucosidase (IC₅₀ = 362.3 ± 9.2 μg/mL) and α-amylase (IC₅₀ = 119.0 ± 17.7 μg/mL). For anti-obesity activities, SE-EA indicated the highest suppression effect on pancreatic lipase (IC₅₀ = 3.67 ± 0.52 mg/mL). Finally, for anti-hypertension activity, SE-EA also demonstrated the strongest inhibitory activity on ACE (IC₅₀ = 626.6 ± 15.0 μg/mL). Close relationships were observed among the parameters of TPC, antioxidant activities, inhibitory activities on α-amylase, α-glucosidase, lipase and ACE (R > 0.9). Moderate correlations were found among the parameters of TFC, antioxidant activities, and suppression of dicarbonyl compounds formation (R = 0.5-0.9). Taken together these in vitro studies reveal the therapeutic potential of SE-EA extract in the prevention and treatment of metabolic disorders.

Very low-density lipoprotein (VLDL)-induced signals mediating aldosterone production

Aldosterone, secreted by the adrenal zona glomerulosa, enhances sodium retention, thus increasing blood volume and pressure. Excessive production of aldosterone results in high blood pressure and contributes to cardiovascular and renal disease, stroke and visual loss. Hypertension is also associated with obesity, which is correlated with other serious health risks as well. Although weight gain is associated with increased blood pressure, the mechanism by which excess fat deposits increase blood pressure remains unclear. Several studies have suggested that aldosterone levels are elevated with obesity and may represent a link between obesity and hypertension. In addition to hypertension, obese patients typically have dyslipidemia, including elevated serum levels of very low-density lipoprotein (VLDL). VLDL, which functions to transport triglycerides from the liver to peripheral tissues, has been demonstrated to stimulate aldosterone production. Recent studies suggest that the signaling pathways activated by VLDL are similar to those utilized by AngII. Thus, VLDL increases cytosolic calcium levels and stimulates phospholipase D (PLD) activity to result in the induction of steroidogenic acute regulatory (StAR) protein and aldosterone synthase (CYP11B2) expression. These effects seem to be mediated by the ability of VLDL to increase the phosphorylation (activation) of their regulatory transcription factors, such as the cAMP response element-binding (CREB) protein family of transcription factors. Thus, research into the pathways by which VLDL stimulates aldosterone production may identify novel targets for the development of therapies for the treatment of hypertension, particularly those associated with obesity, and other aldosterone-modulated pathologies.

Blood pressure from childhood to adolescence in obese youths in relation to insulin resistance and asymmetric dimethylarginine

BACKGROUND AND PROPOSE

Hypertension is the most important cardiovascular complication of obesity, even during childhood. Several studies have demonstrated that there is a natural progression of hypertension from childhood to adulthood. However, there are no data reporting a potential worsening in blood pressure (BP) already moving from the pre-pubertal to the pubertal period in obese youths. The aim of this study was to evaluate early change in BP and its relation to insulin resistance (IR) and asymmetric dimethylarginine (ADMA).

METHODS

Thirty obese children underwent a first assessment when they were pre-pubertal (visit_1) and were re-evaluated after a mean of 4.5 years (visit_2). At both visits, anthropometric parameters were assessed, blood samples were collected for measurement of insulin, glucose and ADMA and a 24-h ambulatory BP monitoring was performed.

RESULTS

At visit_2, the study participants presented increased HOMA-IR and ADMA compared to visit_1 (HOMA-IR: 3.6 ± 2.8 vs 2.8 ± 1.4, p = 0.01; ADMA: 1.57 ± 0.78 vs 0.77 ± 0.52 μmol/l, p < 0.001). Values of 24-h systolic and diastolic BP SDS (0.86 ± 0.79 vs 0.42 ± 0.83, p = 0.001; -0.45 ± 0.82 vs 0.08 ± 0.51, p = 0.001) were significantly increased at visit_2 compared to visit_1. At both visits, BMI-SDS, HOMA-IR and ADMA were associated with 24-h BP. In addition, over-time changes in IR and ADMA influenced changes in systolic blood pressure and diastolic blood pressure from childhood to adolescence (p < 0.05).

CONCLUSIONS

Changes in BP already occur moving from the pre-pubertal to the pubertal period in obese children, and modifications in insulin resistance and ADMA seem to be implicated in this early progression in BP.

Identification of the Vasoconstriction-Inhibiting Factor (VIF), a Potent Endogenous Cofactor of Angiotensin II Acting on the Angiotensin II Type 2 Receptor

BACKGROUND

The renin-angiotensin system and especially the angiotensin peptides play a central role in blood pressure regulation. Here, we hypothesize that an as-yet unknown peptide is involved in the action of angiotensin II modulating the vasoregulatory effects as a cofactor.

METHODS AND RESULTS

The peptide with vasodilatory properties was isolated from adrenal glands chromatographically. The effects of this peptide were evaluated in vitro and in vivo, and the receptor affinity was analyzed. The plasma concentration in humans was quantified in patients with chronic kidney disease, patients with heart failure, and healthy control subjects. The amino acid sequence of the peptide from bovine adrenal glands was HSSYEDELSEVL EKPNDQAE PKEVTEEVSSKDAAE, which is a degradation product of chromogranin A. The sequence of the peptide isolated from human plasma was HSGFEDELSEVLENQSSQAELKEAVEEPSSKDVME. Both peptides diminished significantly the vasoconstrictive effect of angiotensin II in vitro. Therefore, we named the peptide vasoconstriction-inhibiting factor (VIF). The vasoregulatory effects of VIF are mediated by the angiotensin II type 2 receptor. VIF impairs angiotensin II-induced phosphorylation of the p38 mitogen-activated protein kinase pathway but not of extracellular-regulated kinase 1/2. The vasodilatory effects were confirmed in vivo. The plasma concentration was significantly increased in renal patients and patients with heart failure.

CONCLUSIONS

VIF is a vasoregulatory peptide that modulates the vasoconstrictive effects of angiotensin II by acting on the angiotensin II type 2 receptor. It is likely that the increase in VIF may serve as a counterregulatory effect to defend against hypertension. The identification of this target may help us to understand the pathophysiology of renal and heart failure and may form a basis for the development of new strategies for the prevention and treatment of cardiovascular disease.

Adiposity and blood pressure among 55 000 relatively lean rural adults in southwest of China

Obesity is a strong determinant of blood pressure. Uncertainty remains, however, about which indices of adiposity most strongly predict blood pressure, particularly among those who were relatively lean, such as those from rural China. We analyzed cross-sectional data on 55 687 (38.3% men) participants aged 30–79 years who were enrolled into the China Kadoorie Biobank from a rural county in southwest of China during 2004–2008. Measured body mass index (BMI) and waist circumference (WC) were related to blood pressure in multivariable linear regression analyses. The overall mean values of BMI, WC, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 23.3 kg m⁻², 78.0 cm, 129.2 mm Hg and 77.2 mm Hg, respectively. There was a strongly positive, and apparently linear, relationship of BMI and WC with blood pressure, with 1 s.d. higher BMI associated with 4.3/2.3 mm Hg higher SBP/DBP and 1 s.d. WC associated with 3.8/2.1 mm Hg (P<0.0001). Additional adjustment for WC only slightly attenuated the association of BMI with blood pressure, whereas additional adjustment for BMI almost completely eliminated the association of WC with blood pressure. Our findings suggest that in relatively lean Chinese adults, general adiposity is more strongly assciated with blood pressure than central adiposity.

Regulation of aldosterone synthesis and secretion

Aldosterone is a steroid hormone synthesized in and secreted from the outer layer of the adrenal cortex, the zona glomerulosa. Aldosterone is responsible for regulating sodium homeostasis, thereby helping to control blood volume and blood pressure. Insufficient aldosterone secretion can lead to hypotension and circulatory shock, particularly in infancy. On the other hand, excessive aldosterone levels, or those too high for sodium status, can cause hypertension and exacerbate the effects of high blood pressure on multiple organs, contributing to renal disease, stroke, visual loss, and congestive heart failure. Aldosterone is also thought to directly induce end-organ damage, including in the kidneys and heart. Because of the significance of aldosterone to the physiology and pathophysiology of the cardiovascular system, it is important to understand the regulation of its biosynthesis and secretion from the adrenal cortex. Herein, the mechanisms regulating aldosterone production in zona glomerulosa cells are discussed, with a particular emphasis on signaling pathways involved in the secretory response to the main controllers of aldosterone production, the renin-angiotensin II system, serum potassium levels and adrenocorticotrophic hormone. The signaling pathways involved include phospholipase C-mediated phosphoinositide hydrolysis, inositol 1,4,5-trisphosphate, cytosolic calcium levels, calcium influx pathways, calcium/calmodulin-dependent protein kinases, diacylglycerol, protein kinases C and D, 12-hydroxyeicostetraenoic acid, phospholipase D, mitogen-activated protein kinase pathways, tyrosine kinases, adenylate cyclase, and cAMP-dependent protein kinase. A complete understanding of the signaling events regulating aldosterone biosynthesis may allow the identification of novel targets for therapeutic interventions in hypertension, primary aldosteronism, congestive heart failure, renal disease, and other cardiovascular disorders.

Higher blood aldosterone level in metabolic syndrome is independently related to adiposity and fasting plasma glucose

BACKGROUND

Hypoadiponectinemia is a well-known state associated with metabolic syndrome (MetS) and insulin resistance (IR). Recently aldosterone has been highly associated with high blood pressure, and may thus be a possible biomarker for MetS and IR. In this study, we investigate the association of aldosterone with MetS and IR, and compare it with that of adiponectin.

METHODS

In this cross-sectional study, we recruited 556 women receiving physical examinations at a general hospital in central Taiwan. At the time of examination, we collected data on various demographic and physical characteristics and measured blood levels of aldosterone, adiponectin and a variety of metabolic factors. Multiple linear regression analysis was performed using adiponectin or aldosterone as the dependent variables.

RESULTS

We found an inverse correlation between blood adiponectin and aldosterone (γ = -0.11, P = 0.009). Adiponectin levels were lower and aldosterone levels higher in women with MetS that those without (8.1 ± 0.4 vs. 11.5 ± 0.2 μg/mL, P < 0.001 and 691 ± 50 vs. 560 ± 11 pmol/L, P = 0.013, respectively), as they were in women with and without IR (adiponectin 10.4 ± 0.5 vs. 11.3 ± 0.2 μg/mL, P = 0.003 and aldosterone 635 ± 31 vs. 560 ± 11 pmol/L, P = 0.022). Although aldosterone was significantly related to body fat %, fasting plasma glucose and serum creatinine levels, the relationship between adiponectin and aldosterone was not obvious after adjustment in the multivariate analysis.

CONCLUSION

Although aldosterone was related to metabolic factors, including body fat % and fasting plasma glucose in our female subjects, the relationship between aldosterone and adiponectin remains unclear.

Inhibitory effects of tannic acid in the early stage of 3T3-L1 preadipocytes differentiation by down-regulating PPARγ expression

Tannic acid inhibits lipid accumulation in the early stage of 3T3-L1 preadipocytes differentiation by down-regulating PPARγ.

Regulation of apelin and its receptor expression in adipose tissues of obesity rats with hypertension and cultured 3T3-L1 adipocytes

The apelin/APJ system has been implicated in obesity-related hypertension. We investigated the mechanism responsible for the pathogenesis of obesity-related hypertension with a special focus on the crosstalk between AngII/its type 1 receptor (AT1R) signaling and apelin/APJ expression. Sprague-Dawley rats fed a high-fat (obesity-related hypertension, OH) or normal-fat diet (NF) for 15 weeks were randomly assigned to one of two groups and administered vehicle or perindopril for 4 weeks. Compared to the NF rats, the OH rats showed lower levels of plasma apelin and apelin/APJ mRNAs of perirenal adipose tissues, and these changes were restored by perindopril. Administration of the AT1R antagonist olmesartan resulted in the restoration of the reduction of apelin and APJ expressions induced by AngII for 48 h in 3T3-L1 adipocytes. Among several inhibitors for extracellular signal-regulated kinases 1/2 (ERK1/2) PD98059, p38 mitogen-activated protein kinase (p38MAPK) SB203580 and phosphatidylinositol 3-kinase (PI3K) LY294002, the latter showed an additive effect on AngII-mediated inhibitory effects. In addition, the levels of p-Akt, p-ERK and p38MAPK proteins were decreased by long-term treatment with AngII (120 min), and these changes were restored by Olmesartan. Apelin/APJ appears to be impaired in obesity-related hypertension. The AngII inhibition-mediated beneficial effects are likely attributable, at least in part, to restoration of p38/ERK-dependent apelin/APJ expression in diet-induced obesity-related hypertension.

Effect of yellow capsicum extract on proliferation and differentiation of 3T3-L1 preadipocytes

OBJECTIVES

To evaluate the effect of effect of Yellow Capsicum extract (YCE) that is rich in capsaicin on the proliferation and differentiation of 3T3-L1 preadipocytes in vitro.

METHODS

3T3 L1 cells that were exposed to differentiation-inducing medium containing high glucose DMEM (Dulbecco's Modified Eagle's Medium) and subsequently were treated with capsaicin and YCE for their effect on adipocyte differentiation, changes in their triglyceride content, leptin secretion, expression of lipoprotein lipase, PPARγ, and CCAAT/enhancer-binding protein alpha (C/EBPα).

RESULTS

Both YCE and capsaicin inhibited proliferation and differentiation 3T3-L1 preadipocytes and suppressed accumulation of intracellular triglyceride in a dose-dependent manner. In addition, a significant decrease in the expression of lipoprotein lipase (LPL), leptin, PPARγ, and C/EBPα was noted in 3T3-L1 preadipocytes when induced to differentiate by YCE and Capsaicin.

CONCLUSIONS

The potent inhibitory action of YCE and Capsaicin on the differentiation of 3T3-L1 preadipocyte observed suggests that they (YCE and Capsaicin) have the potential to inhibit obesity that needs to be explored in future studies.

Insulin increases the functional activity of the renal NaCl cotransporter

OBJECTIVES

Insulin is recognized to increase renal salt reabsorption in the distal nephron and hyperinsulinemic states have been shown to be associated with increased expression of the renal NaCl cotransporter (NCC). However, the effect of insulin on NCC functional activity has not been reported.

METHODS

Using a heterologous expression system of Xenopus laevis oocytes, a mouse distal convoluted cell line, mDCT15 cells, endogenously expressing NCC, and an ex-vivo kidney perfusion technique, we assessed the effect of insulin on the activity and phosphorylation of NCC. The signaling pathway involved was analyzed.

RESULTS

In Xenopus oocytes insulin increases the activity of NCC together with its phosphorylation at threonine residue 58. Activation of NCC by insulin was also observed in mDCT15 cells. Additionally, insulin increased the NCC phosphorylation in kidney under the ex-vivo perfusion technique. In oocytes and mDCT15 cells, insulin effect on NCC was prevented with inhibitors of phosphatidylinositol 3-kinase (PI3K), mTORC2, and AKT1 kinases, but not by inhibitors of MAP or mTORC1 kinases, suggesting that PI3K-mTORC2-AKT1 is the intracellular pathway required. Additionally, activation of NCC by insulin was not affected by wild-type or mutant versions of with no lysine kinase 1, with no lysine kinase 4, or serum glucocorticoid kinase 1, but it was no longer observed in the presence of wild-type or the dominant negative, catalytically inactive with no lysine kinase 3, implicating this kinase in the process.

CONCLUSION

Insulin induces activation and phosphorylation of NCC. This effect could play an important role in arterial hypertension associated with hyperinsulinemic states, such as obesity, metabolic syndrome, or type 2 diabetes mellitus.

Obesity-related hypertension: pathogenesis, cardiovascular risk, and treatment--a position paper of the The Obesity Society and The American Society of Hypertension

In light of the worldwide epidemic of obesity, and in recognition of hypertension as a major factor in the cardiovascular morbidity and mortality associated with obesity, The Obesity Society and The American Society of Hypertension agreed to jointly sponsor a position paper on obesity-related hypertension to be published jointly in the journals of each society. The purpose is to inform the members of both societies, as well as practicing clinicians, with a timely review of the association between obesity and high blood pressure, the risk that this association entails, and the options for rational, evidenced-based treatment. The position paper is divided into six sections plus a summary as follows: pathophysiology, epidemiology and cardiovascular risk, the metabolic syndrome, lifestyle management in prevention and treatment, pharmacologic treatment of hypertension in the obese, and the medical and surgical treatment of obesity in obese hypertensive patients.

Obesity-related hypertension: pathogenesis, cardiovascular risk, and treatment: a position paper of The Obesity Society and the American Society of Hypertension

In light of the worldwide epidemic of obesity, and in recognition of hypertension as a major factor in the cardiovascular morbidity and mortality associated with obesity, The Obesity Society and the American Society of Hypertension agreed to jointly sponsor a position paper on obesity-related hypertension to be published jointly in the journals of each society. The purpose is to inform the members of both societies, as well as practicing clinicians, with a timely review of the association between obesity and high blood pressure, the risk that this association entails, and the options for rational, evidenced-based treatment. The position paper is divided into six sections plus a summary as follows: pathophysiology, epidemiology and cardiovascular risk, the metabolic syndrome, lifestyle management in prevention and treatment, pharmacologic treatment of hypertension in the obese, and the medical and surgical treatment of obesity in obese hypertensive patients.

The common SNP (rs9939609) in the FTO gene modifies the association between obesity and high blood pressure in Chinese children

Previous studies have suggested that common variants in fat mass- and obesity-associated (FTO) gene are associated with body mass index (BMI) and the risk of obesity. Since obesity plays an important role in the etiology of high blood pressure (HBP), we aim to investigate the association between obesity and HBP in a population with different variants of the FTO gene. A total of 3,494 children (1,775 boys, 50.8 %) aged 6-18 years were recruited for measuring pubertal status, BMI and systolic and diastolic blood pressure. The single nucleotide polymorphism rs9939609 of the FTO gene was genotyped. The blood pressure levels increased by 1.4, 1.5 and 1.8 mmHg for systolic blood pressure and 0.8, 0.9 and 1.2 mmHg for diastolic blood pressure per 1-unit BMI increase in subjects carrying TT, TA and AA genotypes, respectively. After stratifying for FTO rs9939609 genotypes (TT, TA and AA), the odds ratios (95 % confidence intervals) of HBP in obese versus non-obese children were 4.26 (3.18-5.71), 5.13 (2.96-8.90) and 10.37 (1.59-67.43), respectively, with adjustment for age, gender and pubertal status. The FTO rs9939609 SNP modifies the effect of obesity on HBP in Chinese children, with obese ones carrying the AA homozygous genotype of the FTO rs9939609 having the highest risk of developing HBP.

Dietary supplementation oftrans-11-vaccenic acid reduces adipocyte size but neither aggravates nor attenuates obesity-mediated metabolic abnormalities infa/faZucker rats

Conjugated linoleic acid (CLA) present in dairy and ruminant fat has beneficial effects on metabolic syndrome characteristics in humans and some rodent models. Production practices to increase the milk content of CLA are also substantially elevatingtrans-11-vaccenic acid (VA). Questions are being raised whether VA has the same beneficial actions as CLA or has adverse biological effects similar to industrially producedtrans-fatty acids. The present study examined the effects of dietary supplementation of either 0 or 1·5 % (w/w) VA for 8 weeks on lipidaemia, glycaemia, blood pressure, hepatic steatosis, adipocyte size and molecular markers of inflammation and insulin signalling infa/faZucker rats. Dietary supplementation of VA did not alter feed intake, weight gain, blood pressure or organ:body weight (BW) ratios, except the epididymal fat:BW ratio which was lower in the VA group compared with the control group. The total liver lipid concentration as an indicator of hepatic steatosis was not different between the groups. Likewise, there were no changes in fasting lipidaemia, glycaemia or oral glucose tolerance. Although there were no physiological differences observed between the groups, animals supplemented with VA had smaller adipocytes (approximately 7 % smaller than the controls). The VA group also had higher adipophilin and IL-10 protein levels in epididymal adipose tissue (1·7- and 1·4-fold higher than the controls, respectively); however, there were no changes observed in critical nodes of insulin signalling. The present study provides evidence that supplementation with VA, a naturally producedtrans-fat, has some positive effects on adipose tissue and did not exacerbate obesity-mediated metabolic abnormalities.

Epigenetic manifestation of metabolic syndrome and dietary management

SIGNIFICANCE

Metabolic syndrome constitutes a group of disorders such as insulin resistance, hypertension, and hypertriglyceridemia, predisposing an individual to risk factors such as cardiovascular disease, diabetes, obesity, and dyslipidemia. A majority of these diseases are influenced by the environmental factors, nutrient uptake, and genetic profile of an individual that together dysregulate gene function. These genetic and nongenetic factors are reported to introduce epigenetic cues that modulate the gene function which is inherited by the offspring.

RECENT ADVANCES

Considering the epigenetic modulation of the metabolic disorders, nutrigenomics has been distinctly categorized as a branch that deals with modulatory effect of nutrients on metabolic disorders and disease progression by supplementing the individuals with key nutrient-enriched diets which are derived from plant and animal sources.

CRITICAL ISSUES

Nutritional components of the diet regulate the metabolic health of an individual either by controlling the expression of some key genes related to metabolic pathways or by modulating the epigenetic events on such genes. The present article discusses various metabolic disorders in detail and the effect of nutrients on the specific genes causing those disorders. We also highlight the molecular mechanisms of some metabolic disorders through epigenetic modifications and possible therapeutic interventions.

FUTURE DIRECTIONS

With the advent of high-throughput technologies and epigenetic modulation of the metabolic disorders, an altered epigenetic code that is programmed due to improper nutrients can be reverted back by supplementing the diet with various plant-derived compounds. The implication of small molecular drugs is also of utmost significance for challenging the metabolic disorders.

Changes in fitness and fatness on the development of cardiovascular disease risk factors hypertension, metabolic syndrome, and hypercholesterolemia

OBJECTIVES

This study sought examine the independent and combined associations of changes in fitness and fatness with the subsequent incidence of the cardiovascular disease (CVD) risk factors of hypertension, metabolic syndrome, and hypercholesterolemia.

BACKGROUND

The relative and combined contributions of fitness and fatness to health are controversial, and few studies are available on the associations of changes in fitness and fatness with the development of CVD risk factors.

METHODS

We followed up 3,148 healthy adults who received at least 3 medical examinations. Fitness was determined by using a maximal treadmill test. Fatness was expressed by percent body fat and body mass index. Changes in fitness and fatness between the first and second examinations were categorized into loss, stable, or gain groups.

RESULTS

During the 6-year follow-up after the second examination, 752, 426, and 597 adults developed hypertension, metabolic syndrome, and hypercholesterolemia, respectively. Maintaining or improving fitness was associated with lower risk of developing each outcome, whereas increasing fatness was associated with higher risk of developing each outcome, after adjusting for possible confounders and fatness or fitness for each other (all p for trend <0.05). In the joint analyses, the increased risks associated with fat gain appeared to be attenuated, although not completely eliminated, when fitness was maintained or improved. In addition, the increased risks associated with fitness loss were also somewhat attenuated when fatness was reduced.

CONCLUSIONS

Both maintaining or improving fitness and preventing fat gain are important to reduce the risk of developing CVD risk factors in healthy adults.

Adrenal cell aldosterone production is stimulated by very-low-density lipoprotein (VLDL)

Very low-density lipoproteins (VLDL) are a class of large lipoprotein synthesized in the liver. The key function of VLDL, in vivo, is to carry triglyceride from the liver to adipose tissue. As a steroidogenic organ, the adrenal gland mainly uses lipoproteins as sources of cholesterol. Although VLDL receptors have been detected in the human adrenal, the function of VLDL in the adrenal gland remains unknown. Herein, we used primary cultures of human and bovine adrenal cells and the adrenocortical cell line H295R as models to determine the effects of VLDL on adrenal steroidogenesis. Our studies revealed that VLDL significantly increased aldosterone synthesis in all of the models tested. This increase was largely due to VLDL's stimulation of the expression of steroidogenic acute regulatory (StAR) protein and aldosterone synthase (CYP11B2). VLDL increased CYP11B2 mRNA expression in a concentration-dependent manner. Effects of VLDL on CYP11B2 transcript levels were not additive with angiotensin II or potassium but were additive with the cAMP pathway agonists ACTH and forskolin. Nifedipine completely inhibited the effects of VLDL on CYP11B2 mRNA, suggesting that calcium is the main signal transduction pathway used by VLDL in adrenal cells. Indeed, VLDL increased cytosolic free calcium levels. An in vivo study conducted in sucrose-fed rats showed a positive correlation between elevated triglyceride (VLDL) levels in plasma and CYP11B2 expression in the adrenal. In conclusion, we have shown that VLDL can stimulate aldosterone synthesis in adrenocortical cells by increasing StAR and CYP11B2 expression, an event likely mediated by a calcium-initiated signaling cascade.

Progression is accelerated from prehypertension to hypertension in blacks

Prehypertension is a major risk factor for hypertension. Blacks have more prevalent and severe hypertension than whites, but it is unknown whether progression from prehypertension is accelerated in blacks. We examined this question in a prospective cohort study of 18 865 nonhypertensive persons (5733 black [30.4%] and 13 132 white [69.6%]) aged 18 to 85 years. Electronic health record data were obtained from 197 community-based outpatient clinics in the Southeast United States. Days elapsing from study entry to hypertension diagnosis, mainly blood pressure ≥140 mm Hg systolic and/or ≥90 mm Hg diastolic on 2 consecutive visits established conversion time within a maximum observation period of 2550 days. Cox regression modeling was used to examine conversion to hypertension as a function of race, while controlling for age, sex, baseline systolic and diastolic blood pressures, body mass index, diabetes mellitus, and chronic kidney disease. The covariable adjusted median conversion time when 50% became hypertensive was 365 days earlier for blacks than whites (626 versus 991 days; P<0.001). Among covariables, baseline systolic blood pressure 130 to 139 mm Hg (hazard ratio: 1.77 [95% CI: 1.69 to 1.86]) and 120 to 129 mm Hg (hazard ratio: 1.52 [95% CI: 1.44 to 1.60]), as well as age ≥75 years (hazard ratio: 1.40 [95% CI: 1.29 to 1.51]) and 55 to 74 years (hazard ratio: 1.29 [95% CI: 1.23 to 1.35]) were the strongest predictors of hypertension. Additional predictors included age 35 to 54 years, diastolic blood pressure 80 to 89 mm Hg, overweight and obesity, and diabetes mellitus (all P<0.001). Conversion from prehypertension to hypertension is accelerated in blacks, which suggests that effective interventions in prehypertension could reduce racial disparities in prevalent hypertension.

Cardiac hypertrophy and fibrosis in the metabolic syndrome: a role for aldosterone and the mineralocorticoid receptor

Obesity and hypertension, major risk factors for the metabolic syndrome, render individuals susceptible to an increased risk of cardiovascular complications, such as adverse cardiac remodeling and heart failure. There has been much investigation into the role that an increase in the renin-angiotensin-aldosterone system (RAAS) plays in the pathogenesis of metabolic syndrome and in particular, how aldosterone mediates left ventricular hypertrophy and increased cardiac fibrosis via its interaction with the mineralocorticoid receptor (MR). Here, we review the pertinent findings that link obesity with elevated aldosterone and the development of cardiac hypertrophy and fibrosis associated with the metabolic syndrome. These studies illustrate a complex cross-talk between adipose tissue, the heart, and the adrenal cortex. Furthermore, we discuss findings from our laboratory that suggest that cardiac hypertrophy and fibrosis in the metabolic syndrome may involve cross-talk between aldosterone and adipokines (such as adiponectin).

Effect of weight gain on cardiac autonomic control during wakefulness and sleep

Obesity has been associated with increased cardiac sympathetic activation during wakefulness, but the effect on sleep-related sympathetic modulation is not known. The aim of this study was to investigate the effect of fat gain on cardiac autonomic control during wakefulness and sleep in humans. We performed a randomized, controlled study to assess the effects of fat gain on heart rate variability. We recruited 36 healthy volunteers, who were randomized to either a standardized diet to gain ≈4 kg over 8 weeks followed by an 8-week weight loss period (n=20) or to serve as a weight-maintainer control (n=16). An overnight polysomnogram with power spectral analysis of heart rate variability was performed at baseline, after weight gain, and after weight loss to determine the ratio of low-frequency to high-frequency power and to examine the relationship between changes in heart rate variability and changes in insulin, leptin, and adiponectin levels. Mean weight gain was 3.9 kg in the fat gain group versus 0.1 kg in the maintainer group. Low frequency/high frequency increased both during wakefulness and sleep after fat gain and returned to baseline after fat loss in the fat gain group and did not change in the control group. Insulin, leptin, and adiponectin also increased after fat gain and fell after fat loss, but no clear pattern of changes was seen that correlated consistently with changes in heart rate variability. Short-term fat gain in healthy subjects is associated with increased cardiac sympathetic activation during wakefulness and sleep, but the mechanisms remain unclear.

The role of low-grade inflammation in the polycystic ovary syndrome

PCOS is not only the most frequent cause of oligomenorrhea in young women, but also a metabolic disorder characterized by insulin resistance, glucose intolerance, dyslipidemia, and obesity, especially the visceral phenotype. PCOS represents a broad spectrum of endocrine and metabolic alterations which change with age and with increasing adiposity. In fact, during adolescence and youth the predominant clinical manifestations of PCOS are menstrual abnormalities, hirsutism and acne, whereas in peri-menopausal and post-menopausal periods metabolic disorders and an increased risk for cardiovascular diseases prevail. The pathogenetic links between PCOS and metabolic or cardiovascular complications are still debated. However, recent evidence has been focused on a condition of low-grade chronic inflammation as a potential cause of the long-term consequence of the syndrome. In this review we describe the state of low-grade inflammation observed in PCOS. In addition, we hypothesize the potential mechanisms responsible for the generation of this inflammatory state and the role played by low-grade inflammation in linking hyperandrogenism and insulin resistance with the metabolic and cardiovascular long-term complications of the syndrome.

The role of oestrogen in the pathogenesis of obesity, type 2 diabetes, breast cancer and prostate disease

A detailed review of the literature was performed in a bid to identify the presence of a common link between specific hormone interactions and the increasing prevalence of global disease. The synergistic action of unopposed oestrogen and leptin, compounded by increasing insulin, cortisol and xeno-oestrogen exposure directly initiate, promote and exacerbate obesity, type 2 diabetes, uterine overgrowth, prostatic enlargement, prostate cancer and breast cancer. Furthermore these hormones significantly contribute to the incidence and intensity of anxiety and depression, Alzheimer's disease, heart disease and stroke. This review, in collaboration with hundreds of evidence-based clinical researchers, correlates the significant interactions these hormones exert upon the upregulation of p450 aromatase, oestrogen, leptin and insulin receptor function; the normal status quo of their binding globulins; and how adduct formation alters DNA sequencing to ultimately produce an array of metabolic conditions ranging from menopausal symptoms and obesity to Alzheimer's disease and breast and prostate cancer. It reveals the way that poor diet, increased stress, unopposed endogenous oestrogens, exogenous oestrogens, pesticides, xeno-oestrogens and leptin are associated with increased aromatase activity, and how its products, increased endogenous oestrogen and lowered testosterone, are associated with obesity, type 2 diabetes, Alzheimer's disease and oestrogenic disease. This controversial break-through represents a paradigm shift in medical thinking, which can prevent the raging pandemic of diabetes, obesity and cancer currently sweeping the world, and as such, it will reshape health initiatives, reduce suffering, prevent waste of government expenditure and effectively transform preventative medicine and global health care for decades.

Linkage of angiotensinogen gene polymorphisms with hypertension in a sibling study of Hong Kong Chinese

OBJECTIVE

The angiotensinogen gene has been linked with human essential hypertension in whites but the relationship in Asian populations has been less consistent. This study aimed to examine genetic associations between hypertension and the M235T, T174M, and G-217A polymorphisms of the angiotensinogen gene in Chinese siblings.

METHODS

We studied members of 126 families with a hypertensive proband, including 434 siblings, of which 178 were hypertensive. Parental history of hypertension was recorded. The M235T, T174M, and G-217A polymorphisms were examined using a microarray method, validated by sequencing. The transmission disequilibrium test was applied to identify whether the genetic polymorphism loci were related to hypertension. Haplotype analysis of the combined polymorphisms was applied using the TRANSMIT program. Linkage study was conducted by applying the affected pedigree member method.

RESULTS

A significant overtransmission was observed for the T235 allele at the M235T polymorphism and hypertension (chi2 = 4.41, P = 0.036) but not for the T174M and G-217A polymorphisms. The haplotype analysis showed a significant association with the haplotypes of paired markers (T174 and T235) with chi2 value of 8.131 (P = 0.004; global test chi2 = 9.131, P = 0.028). Linkage between M235T and hypertension was detected (T = -2.25, P = 0.019), and a tendency for linkage with central obesity-related hypertension was found for the M235T and T174M polymorphisms (P = 0.0087 and P = 0.01).

CONCLUSION

The M235T and T174M variants, especially the T235 allele, contribute to an increased risk of hypertension in these Chinese patients.

Periadventitial adipose tissue promotes endothelial dysfunction via oxidative stress in diet-induced obese C57Bl/6 mice

BACKGROUND

Biological substances derived from perivascular fat modulate vascular tone, thus alterations in periadventitial adipose tissue (PVAT) may aggravate endothelial dysfunction in obesity.

METHODS AND RESULTS

Male C57Bl/6 mice were fed either a high-fat diet or standard laboratory chow for 8 months. Vascular responses were studied in organ bath chambers from abdominal aortic ring preparations in the absence or presence of PVAT. The amount of PVAT as well as the cross-sectional area of adipocytes were increased in obese mice. In the presence of PVAT, obese aortas displayed impaired endothelium-dependent vasodilation whereas endothelium-independent vasodilatation was unaltered. Endothelium-dependent vasodilatation was restored after removal of PVAT and after reducing superoxide and hydrogen peroxide formation in the vascular wall by Tiron or polyethylene-glycol-catalase, respectively. PVAT from obese mice showed increased formation of hydrogen peroxide and superoxide. The PVAT-derived oxidative stress was abolished by pretreatment with the reduced nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase inhibitor, apocynin. The anti-contractile function of PVAT found in lean mice was completely abolished in obese mice, but partially restored after pretreatment with Tiron. The mRNA expressions of monocyte chemotactic protein-1, leptin and NADPH oxidase were markedly higher in the PVAT of obese than lean mice.

CONCLUSIONS

PVAT promotes endothelial dysfunction in diet-induced obese C57Bl/6 mice via mechanisms that are linked to increased NADPH oxidase-derived oxidative stress and increased production of pro-inflammatory cytokines.