Obesity-hypertension: an ongoing pandemic

Quantification of lipid droplets and associated proteins in cellular models of obesity via high-content/high-throughput microscopy and automated image analysis

Intracellular lipid droplets are associated with a myriad of afflictions including obesity, fatty liver disease, coronary artery disease, and infectious diseases (eg, HCV and tuberculosis). To develop high-content analysis (HCA) techniques to analyze lipid droplets and associated proteins, primary human preadipocytes were plated in 96-well dishes in the presence of rosiglitazone (rosi), a PPAR-(c) agonist that promotes adipogenesis. The cells were then labeled for nuclei, lipid droplets, and proteins such as perilipin, protein kinase C (PKC), and hormone-sensitive lipase (HSL). The cells were imaged via automated digital microscopy and algorithms were developed to quantify lipid droplet (Lipid Droplet algorithm) and protein expression and colocalization (Colocalization algorithm). The algorithms, which were incorporated into Vala Science Inc's CyteSeer((R)) image cytometry program, quantified the rosi-induced increases in lipid droplet number, size, and intensity, and the expression of perilipin with exceptional consistency (Z' values of 0.54-0.71). Regarding colocalization with lipid droplets, Pearson's correlation coefficients of 0.38 (highly colocalized), 0.16 (moderate), and -0.0010 (random) were found for perilipin, PKC, and HSL, respectively. For hepatocytes (AML12, HuH-7, and primary cells), the algorithms also quantified the stimulatory and inhibitory effect of oleic acid and triacsin C on lipid droplets (Z's > 0.50) and ADFP expression/colocalization. Oleic acid-induced lipid droplets in HeLa cells and macrophages (THP-1) were also well quantified. The results suggest that HCA techniques can be utilized to quantify lipid droplets and associated proteins in many cell models relevant to a variety of diseases.

Tonic GABAergic inhibition of sympathetic preganglionic neurons: a novel substrate for sympathetic control

The sympathetic tone is primarily defined by the level of activity of the sympathetic preganglionic neurons. We report a novel inhibitory influence on sympathetic activity, that of tonic GABAergic inhibition which could have a profound global effect on sympathetic outflow. Recording from identified SPNs in the intermediolateral cell column (IML) of rat spinal cord slices, application of the GABA receptor antagonist bicuculline, but not gabazine, elicited a change in voltage that lasted for the duration of application. This response was mediated by a direct effect on SPNs since it persisted in tetrodotoxin and low Ca(2+)/high Mg(2+) and the amplitude of responses were related to Cl(-) concentration in patch solutions. Such tonic inhibitory responses were not observed in interneurons, the other neuronal type in the IML, although ongoing IPSPs were antagonized in these neurons. The effects of bicuculline were enhanced by diazepam but not zolpidem or the GABA modulators THIP and THDOC suggesting a role for alpha5 subunits. PCR using primers for the alpha5 and delta subunits indicated the presence of alpha5, but not delta subunits in the IML. Firing rates of SPNs were enhanced by bicuculline and decreased by diazepam indicating that this tonic inhibition has a profound effect on the excitability of SPNs. These data indicate a novel influence for controlling the activity of SPNs regardless of their function.

Body mass index associated with elevated blood pressure in Mexican school-aged adolescents

OBJECTIVE

To evaluate the relationship between blood pressure and body mass index among adolescents.

METHODS

A 14-month period cross-sectional study was carried out among 2387 adolescents attending public schools in the state of Morelos, Mexico between 2005 and 2007. We measured blood pressure during four visits, obtaining elevated blood pressure prevalence according to the guidelines for children and adolescents of the United States National Educational Program on High Blood Pressure (at least three visits needed to assess elevated blood pressure on the basis of 95th percentile specific for gender, age and height). We used specific body mass index percentiles for age and gender. We employed multiple linear and Cox proportional hazards models to identify factors related to elevated blood pressure.

RESULTS

The overall prevalence of elevated blood pressure was 3.9%. Multiple linear models showed that overweight subjects had systolic and diastolic blood pressures that were 5.1 and 2.5 mmHg higher, respectively, compared with adolescents with a normal body mass index, while obese subjects had 11.3 and 6.2 mmHg higher levels, respectively. Cox proportional hazards models indicated high risk of elevated blood pressure among overweight (RR, 3.6; 95%CI, 1.5-8.5) and obese subjects (RR, 14.2; 95%CI, 7.2-27.75) compared with adolescents with a normal body mass index.

CONCLUSION

Our results suggest that a higher body mass index is associated with elevated systolic and diastolic blood pressure levels, indicating the importance of incorporating strategies for ongoing screening and for promoting educational programs on healthy lifestyles to prevent hypertension in adolescents.

Screening for kidney disease in children on World Kidney Day in Jalisco, Mexico

World Kidney Day (WKD) is intended to raise awareness and increase detection of chronic kidney disease (CKD), but most emphasis is placed on adults rather than children. We examined yield of screening for CKD and hypertension among poor children in Mexico. On WKD (2006, 2007), children (age < 18 years) without known CKD were invited to participate at two screening stations. We measured body mass index (BMI), blood pressure, and serum creatinine, and performed dipstick urinalysis. The Schwartz equation was used to estimate glomerular filtration rate (GFR; reduced GFR defined as < 60 ml/min per 1.73 m(2)). Proteinuria and hematuria were defined by a reading of >or= 1+ protein or blood on dipstick. Hypertension was defined by gender, age, and height-specific norms. In total, 240 children were screened (mean age 8.9 +/- 4.1 years; 44.2% male). Proteinuria and hematuria were detected in 38 (16.1%) and 41 (17.5%), respectively; 15% had BMI > 95th percentile for age. Reduced GFR was detected in four (1.7%) individuals. Systolic hypertension was more prevalent in younger children (age 0-8 years, 19.6%; age 9-13 years, 7.1%; age 14-17 years, 5.3%) suggesting a possible white-coat effect. Hematuria, proteinuria, hypertension and obesity were frequently detected among children in a community based screening program in Mexico. This form of screening might be useful in identifying children with CKD and hypertension in developing nations.

[Hypertension in obese children and adolescents]

Obesity, especially upper body fat distribution, has become an increasingly important medical problem in children and adolescents. Outcomes related to childhood obesity include, as in adult population, hypertension, type 2 diabetes mellitus, dyslipidemia, left ventricular hypertrophy, obstructive sleep apnea, orthopedic and socio-psychological problems. Obese children are at approximately 3-fold higher risk for hypertension from non-obese ones. Obesity-hypertension appears to be characterized by a preponderance of isolated systolic hypertension, increased heart rate and blood pressure variability, increased levels of plasma catecholamine and aldosterone, and salt-sensitivity. Lifestyle changes of weight loss, healthier diet and regular physical exercise are effective in obesity-hypertension control, though pharmacological treatment is frequently necessary. Screening for dyslipidemia and impaired glucose tolerance should be performed in paediatric patients with obese hypertension on regular basis, at least once annually or semiannually to discover metabolic syndrome and to prevent its increased cardiovascular risk. Of course, prevention of obesity is the primary goal.

Obesity and hypertension: mechanisms, cardio-renal consequences, and therapeutic approaches

The increasing prevalence of obesity in the industrialized world is causing an alarming epidemic. Almost 70% of American adults are overweight or obese. The link between increasing body weight and hypertension is well established. Obesity hypertension through metabolic, endocrinic, and systemic hemodynamic alteration causes structural vascular and cardiac adaptations that trigger concentric, eccentric left ventricular hypertrophy and electrophysiological changes, which may increase the risk for congestive heart failure and sudden cardiac death as a result of arrhythmias. The increased renal blood flow in conjunction with a decreased renal vascular resistance causes renal hyperperfusion and hyperfiltration. Such changes lead to glomerulomegaly, focal segmental glomerulosclerosis, tubulointerstitial inflammation, and fibrosis that characterize the renal damage in obese hypertensive subjects. We propose that weight reduction, with the addition of other nonpharmacological approaches that included exercise and reduction in alcohol intake, should be the first choice to treat obesity hypertension. Salt restriction may be helpful only in salt-sensitive patients. The benefits of diet in obese patients include improvement of insulin sensitivity, reduction in sympathetic nervous and renin angiotensin system activities, and restoration of leptin sensitivity. As a consequence of these and other metabolic changes, the previously described systemic and renal hemodynamic alterations improved and the cardiovascular and renal morphological changes induced by obesity were lessened. After reviewing the medications available, we believe that owing to the cardiovascular and renal morbidity and mortality that characterized obesity hypertension, the ACEI or ARBs offer the best cardio-renal protection and should be the pharmacologic treatment of choice. If these alone do not control BP adequately, then a low-dose diuretic should be added as a second approach. Although we strongly believe in our proposal, more multicenter long-term clinical pharmacological trials are needed to evaluate the efficacy and safety of the antihypertensive approaches in the treatment of obesity hypertension.

Not all obese subjects of multiethnic origin are at similar risk for developing hypertension and type 2 diabetes

BACKGROUND

Whether insulin resistance and not obesity per se is the major contributor to clinical outcomes associated with obesity has not been fully established. This study evaluated in a group of obese Brazilians of multiethnic origin to what extent the prevalence of hypertension and other cardiometabolic risk factors varies as a function of the degree of insulin sensitivity.

METHODS

The study involved 118 individuals (mean age of 44+/-12 years; BMI=38.6+/-7.9 kg/m(2)) without evidence of diabetes or cardiovascular disease. Insulin resistance was assessed by HOMA-IR index, which was used to stratify patients into tertiles.

RESULTS

The mean HOMA-IR in tertile 1, the most insulin-sensitive group, was 2.7+/-0.8 and in tertile 3, the most insulin-resistant group, 9.1+/-2.4 (P<0.001). Mean arterial pressure showed a linear and significant variation across the HOMA-IR tertiles 1, 2, and 3 (94.3+/-11.7; 98.7+/-11.4; 105.0+/-12.4 mm Hg), as did fasting plasma glucose (93.6+/-12.1; 98.1+/-12.7; 100.0+/-11.0 mg/dL), uric acid (4.7+/-1.4; 5.9+/-1.9; 6.3+/-1.4 mg/dL), HDL-cholesterol (48.1+/-11.6; 46.5+/-10.5; 42.2+/-8.0 mg/dL), and plasma adiponectin (7.8+/-3.3; 7.0+/-2.8; 6.3+/-6.5 microg/mL), respectively. The results indicated that 27.5% of our patients had dysglicemia, 28.2% had hypertriglyceridemia, and 30.7% had arterial hypertension in the most insulin-sensitive tertile, when compared with 51%, 53.8% and 79.4%, respectively, in the most insulin-resistant tertile. A stepwise regression analysis showed that only HOMA-IR and age independently affected the risk for increased systolic blood pressure.

CONCLUSION

In conclusion, our findings have shown that the risk of developing essential hypertension, type 2 diabetes, and cardiovascular disease is accentuated in obese individuals who are also more insulin resistant.

Association of a common variant of the leptin gene with blood pressure in an obese Brazilian population

BACKGROUND

This study assessed in obese Brazilians subjects whether a common variant of leptin gene, -2548G>A, is associated with blood pressure changes.

METHODS

A total of 140 subjects, 99 women; mean age of 45.2 +/- 12.4 years; body mass index (BMI) = 38.5 +/- 8.0 kg/m2 were included. Blood pressure was recorded using Dinamap 1846 (Critikon, Tampa, FL). Molecular analysis was made by use of PCR and restriction fragment-length polymorphism analysis. Plasma insulin and leptin concentrations were determined by radioimmunoassay.

RESULTS

AA homozygotes, in comparison with the G-allele carriers, showed significant lower levels of systolic, diastolic, and mean arterial pressure (120 +/- 10 vs. 132 +/- 17 mm Hg, P = 0.01; 75 +/- 6 vs. 84 +/- 12 mm Hg, P = 0.009; 92 +/- 7 vs. 100 +/- 12 mm Hg, P = 0.007, respectively). The differences in blood pressure remained significant after adjusting for the influence of gender, age, obesity, and body fat distribution as well as for leptin, insulin, and homeostasis model assessment of insulin resistance. A stepwise regression analysis confirmed that the LEP AA genotype independently predicted blood pressure changes. On the other hand, in GG homozygotes, insulinemia showed a significant association with blood pressure values. This suggests that common LEP genotype carriers exhibiting high insulin levels, reflecting an insulin-resistant state, were particularly prone to higher blood pressure levels.

CONCLUSIONS

Our results showing that higher blood pressure levels were found with the most prevalent -2548G>A genotype, whereas patients with the AA genotype seemed to be protected from hypertension, indicate that the -2548G>A polymorphism of LEP appears to be an important mediator of obesity hypertension.

Progress and controversies: treating obesity and insulin resistance in the context of hypertension

Improvements in hypertension treatment and control are challenged by the increasing incidence of metabolic risk factors for hypertension, in particular, obesity and insulin resistance. Such risk factors can increase the severity of hypertension and can interact via a multitude of hormonal and inflammatory pathways. Their presence may affect antihypertensive agent choice with regard to antihypertensive efficacy as well as potential synergistic or antagonistic effects on inflammatory status and progression to diabetes. Furthermore, an increasing number of pharmacologic options are available to promote weight loss and insulin sensitivity that may affect blood pressure directly and indirectly. This review considers the metabolic basis for the complex interactions of hypertension with obesity and insulin resistance, and it assesses the clinical evidence for an impact of weight loss and insulin-sensitizing treatment on blood pressure. Awareness of these pathophysiologic interrelations and their implications for treatment are likely to be of increasing importance for successful blood pressure management.

Undernutrition and obesity associated with high blood pressure in children and adolescents from João Pessoa, Paraíba, Brazil

The objective of this study was to describe the prevalence, correlation, and association of undernutrition and obesity with high blood pressure (HBP). One thousand five hundred seventy (1570) students (808 boys and 762 girls), aged 7-12 years, from João Pessoa, Paraíba (Northeastern Brazil) participated. Measurements of stature, body weight, skinfolds [triceps (TS) and subscapular (SS)], upper-arm circumference (UAC), upper-arm fat area (UAFE), total upper-arm area (TUAA), and BP were taken. Four criteria were adopted to classify undernutrition and obesity. HBP was defined as systolic BP (SBP) and/or diastolic BP (DBP) values >or=90th percentile. Analysis of covariance, Spearman's correlation, logistic regression, and multiple linear regression were used. In the logistic regression model, undernutrition was not associated with HBP; however, the chances of HBP increased when two or more obesity indicators were present [boys: odds ratio (OR) = 2.08, 95% confidence interval (CI 95%) = 1.26-3.41; girls: OR = 2.26, CI 95% = 1.44-3.55]. In the multiple regression, the BMI, SS, and UAFE explained 15% of the variance of high SBP (r (2) = 0.153) in boys, whereas the body mass index (BMI) and TUAA accounted for 16% of the variance of the SBP (r (2) = 0.166) in girls. The DBP was influenced by the SS in boys (r (2) = 0.022) and the TUAA (r ( 2 ) = 0.054) in girls. There was an association between obesity and HBP. The BMI, SS, and UAFE in boys and the BMI and TUAA in girls explained approximately 16% of elevated SBP.

Leptin is associated with blood pressure and hypertension in women from the National Heart, Lung, and Blood Institute Family Heart Study

Leptin is a key neuroendocrine hormone regulating food intake, metabolism, and fat accumulation, and it may also affect blood pressure and contribute to hypertension through sympathetic activation in the vasculature or at the renal level. Although previous studies have shown that the distribution of leptin is significantly different between males and females, as is the risk of hypertension between males and females, results regarding the role of leptin in the gender-specific regulation of blood pressure are controversial. Thus, we performed family-based association analyses in the National Heart, Lung, and Blood Institute Family Heart Study to test the hypothesis that LEPTIN gene variants and the plasma leptin level influence variability in blood pressure and the risk of hypertension differently by gender. We identified significant associations between LEPTIN single nucleotide polymorphisms with blood pressure and hypertension, but in postmenopausal women only. We also identified significant associations between plasma leptin levels and both blood pressure and hypertension in women. The current study supports a role for LEPTIN and plasma leptin levels in blood pressure regulation in women. It also provides insight into the gender differences in hypertension, as well as the differential distribution and activity of leptin in men and women.

A 6-month exercise intervention among inactive and overweight favela-residing women in Brazil: the Caranguejo Exercise Trial

OBJECTIVES

We examined the viability and efficacy of a known quantity of exercise in facilitating weight loss among previously sedentary or irregularly active overweight and obese adult women residing in a slum (favela) in Brazil.

METHODS

In this randomized controlled trial, 156 women were randomized to a control or intervention group (78 in each group). Exercise was supervised, consisting of three 50-minute aerobic sessions each week for 6 months.

RESULTS

Ninety-one percent (71) of the participants in the intervention group completed 6 months of the exercise program. At 6 months, women in the treatment group showed significant reduction in weight (mean=-1.69 kg; 95% confidence interval [CI]=-2.36,-1.03) and body mass index (mean=-0.63 kg/m2; 95% CI=-0.97, -0.30) compared with controls (P for both<.001).

CONCLUSIONS

A moderately intense, structured exercise program resulted in modest weight loss in women when sustained for 6 months.

Circulating leptin and stress-induced cardiovascular activity in humans

Obesity is associated with an elevated risk of hypertension and cardiovascular disease. The adipocyte hormone leptin, which stimulates energy expenditure in animals by activating the sympathetic nervous system (SNS), is believed to play a role in this association. However, evidence in humans remains sparse. We investigated the relationship between circulating leptin and cardiovascular and inflammatory responses to acute psychological stress in humans. Participants were 32 men and 62 women aged 18-25 years. Cardiovascular activity was assessed using impedance cardiography at baseline, during acute laboratory stress, and during a 45-min recovery period. Plasma cytokines were measured in blood drawn at baseline and 45-min poststress. In women only, baseline plasma leptin was significantly associated with stress-induced changes in heart rate (beta = 0.53, P = 0.006), heart rate variability (HRV) (beta = -0.44, P = 0.015), and cardiac preejection period (PEP) (beta = -0.51, P = 0.004), independent of age, adiposity, and smoking. Women's plasma leptin levels also correlated with stress-induced elevations in the proinflammatory cytokine interleukin-6 (IL-6) (beta = 0.35, P = 0.042). Circulating leptin is an independent predictor of sympathetic cardiovascular activity, parasympathetic withdrawal, and inflammatory responses to stress in women. Because cardiovascular and inflammatory stress responses are predictive of future cardiovascular disease, leptin may be a mechanism mediating the adverse effects of stress and obesity on women's cardiovascular health.

The influence of body mass index obesity status on vascular surgery 30-day morbidity and mortality

OBJECTIVE

Mild obesity may have a protective effect against some diseases, termed an "obesity paradox." This study examined the effect of body mass index (Kg/m(2) BMI) on surgical 30-day morbidity and mortality in patients undergoing vascular surgical procedures.

METHODS

As part of the National Surgical Quality Improvement Program (NSQIP), demographic and clinical risk variables, mortality, and 22 defined complications (morbidity) were obtained over three years from vascular services at 14 medical centers. At each medical center, patients from the operative schedule were prospectively and systematically enrolled according to NSQIP protocols. Outcomes and risk variables were compared across NIH-defined obesity classes (underweight [BMI<or=18.5], normal [18.5<BMI<25], overweight [25<BMI<or=30], obese I [30<BMI<or=35], obese II [35<BMI<or=40], and obese III [BMI>40]) using analysis of variance and means comparisons. Logistic regression was used to control for other risk factors.

RESULTS

Vascular procedures in 7,543 patients included lower extremity revascularization (24.6%), aneurysm repair (17.4%), cerebrovascular procedures (17.3%), amputations (9.4%), and "other" procedures (31.3%). In the entire cohort, there were 1,659 (22.0%) patients with complications and 295 (3.9%) deaths. Risk factors of hypertension and diabetes increased with BMI (analysis of variance [ANOVA] P < .05) as expected; smoking, disseminated cancer, and stroke decreased (ANOVA P < .01). Twenty other risk factors, as well as mortality and morbidity, had "U" or "J"-shaped distributions with the highest incidence in underweight and/or obese class III extremes but reduced minimums in overweight or obese I classes (ANOVA P < .05). After controlling for age, gender, and operation type, mortality risk remained lowest in obese class I patients (Odds ratio [OR] 0.63, P = .023) while morbidity risk was highest in obese class III patients (OR 1.70, P = .0003), due to wound infection, thromboembolism, and renal complications.

CONCLUSION

Underweight patients have poorer outcomes and class III obesity is associated with increased morbidity. Mildly obese patients have reduced co-morbid illness, surprisingly even less than normal-class patients, with correspondingly reduced mortality. Mild obesity is not a risk factor for 30-day outcomes after vascular surgery and confers an advantage.

Asthma, environmental risk factors, and hypertension among Arab Americans in metro Detroit

Asthma and obesity-related health problems disproportionately impact low-income ethnic minority communities residing in urban areas. Environmental risk factors, particularly those related to housing and indoor air, may impact the development or exacerbation of asthma. There is increasing evidence to suggest a link between obesity-related health problems and asthma. Previous studies have also reported that immigrant status may influence myriad risk factors and health outcomes among immigrant populations. The Arab American Environmental Health Project (AAEHP) was the first study to explore environmental health problems among Arab Americans. This paper examined whether hypertensive status modified the relationship between environmental risk factors and asthma among Arab Americans in metro Detroit. An environmental risk index (ERI) was used to quantify household environmental risk factors associated with asthma. Physician diagnosed hypertension was self-reported, and asthma status was determined using responses to a validated symptoms checklist and self-reported diagnosis by a physician. Hypertension significantly modified the relationship between ERI and asthma in this study population. The positive association between household environmental risk factors and asthma was stronger among participants diagnosed with hypertension. Effect modification of the relationship between environmental risk factors and asthma could have serious implications among high-risk communities. However, further research is needed to elucidate the relationships between hypertension, environmental risk factors, and asthma.

Visfatin, low-grade inflammation and body mass index (BMI)

OBJECTIVE

Visfatin is an adipokine with revealing roles in inflammatory mechanisms but its implication in inflammation related to excessive adiposity/obesity is not studied yet. Our aim was to investigate the relations of visfatin with inflammation markers and body mass index (BMI) in the peripheral blood mononuclear cells (PBMCs), a type of cells closely related to inflammatory mechanisms.

DESIGN

Cross-sectional study, quantification of visfatin, TNF-alpha, IL-6 mRNA in PBMCs.

PATIENTS

Eighty-three supposed healthy individuals from the STANISLAS cohort, belonging in three BMI categories: BMI < 25 kg/m(2) (lean), 25 kg/m(2) <or= BMI < 30 kg/m(2) (overweight) or BMI >or= 30 kg/m(2) (obese).

MEASUREMENTS

We measured visfatin gene expression (by real-time quantitative PCR), in relation to gene expression of the pro-inflammatory cytokines TNF-alpha, IL-6 in PBMCs and to anthropometric parameters (weight, BMI, waist : hip ratio), blood pressure, lipid profile, glucose and inflammatory markers (C-reactive protein, lymphocyte count).

RESULTS

Visfatin expression in PBMCs was significantly associated with BMI in a negative way (r = -0.21, P = 0.05). Global anova analysis test for lean and over-weight/obese individuals showed a negative significant association between visfatin expression in PBMCs and BMI both for men and women (P = 0.05 and P = 0.01, respectively) and these associations remained significant after separating subjects in three groups (lean, overweight, obese) for men and women (P = 0.02 and P = 0.05, respectively). Correlation analysis between levels of expression of visfatin and TNF-alpha showed a significant positive linear association (r(2) = 0.27, P < 0.0001).

CONCLUSION

These findings reveal a probable new role of visfatin in inflammation reflected in PBMCs, in the context of obesity.

The triglyceride/HDL-cholesterol ratio as a marker of cardiovascular risk in obese children; association with traditional and emergent risk factors

OBJECTIVES

To determine the presence of traditional and emergent cardiovascular risk factors and to evaluate the triglyceride/high-density lipoprotein cholesterol (Tg/HDL-C) ratio as a marker for cardiovascular disease and metabolic syndrome (MS) in obese children.

MATERIAL AND METHODS

Sixty-seven prepubertal children of both sexes, between the ages of 6 and 12 yr, 20 normal-weight children, 18 overweight, and 29 obese subjects, were studied. Anthropometric measures, blood pressure, body mass index (BMI), and fat mass (FM), were measured. Plasma glucose, serum insulin, lipid profile, C-reactive protein (CRP), and leptin concentrations were quantified. Glucose and insulin concentrations 2 h post-glucose load were determined. The Tg/HDL-C ratio, homeostasis model assessment index (HOMA), and quantitative insulin sensitivity check index (QUICKI) were calculated.

RESULTS

Systolic, diastolic, and mean blood pressures (MBP), low-density lipoprotein cholesterol (LDL-C), Tg/HDL-C, total cholesterol/HDL-C, LDL-C/HDL-C ratios, basal and 2 h postload insulin, CRP, and leptin were significantly higher and the QUICKI index were lower in the obese group. MBP, Tg/HDL-C ratio, HOMA, CRP, and leptin levels showed a positive and significant correlation and QUICKI a negative correlation with abdominal circumference, BMI, and FM. The Tg/HDL-C ratio correlated positively with MBP. The frequency of MS in the obese group was 69%. While Tg/HDL-C ratio, CRP, and leptin were higher and the values of QUICKI were lower in subjects with MS, it was the Tg/HDL-C ratio and the BMI that significantly explained the MS.

CONCLUSIONS

Obesity increases the cardiovascular risk in childhood. The Tg/HDL-C ratio could be a useful index in identifying children at risk for dyslipidemia, hypertension, and MS.

New aspects of the relationship among hypertension, obesity, and the kidneys

Recent studies have highlighted the association between obesity and chronic renal disease. Overweight has been shown to be a survival advantage in patients on maintenance hemodialysis therapy. However, in patients with preterminal renal failure, obesity may contribute to the progression of renal disease. Data collected from the Prevention of Renal and Vascular End-stage Disease study suggest that changes in weight directly influence albuminuria, hinting that albumin excretion could be used in the general population as a surrogate marker for risk of developing chronic kidney disease. The causal pathways linking excess weight to chronic kidney disease and hypertension are briefly reviewed in this article, and therapeutic approaches to combat this growing health problem are highlighted.

Abdominal obesity and inflammation predicts hypertension among prehypertensive men and women: the ATTICA Study

The aim of this work was to assess the 5-year incidence of hypertension and its predictors among prehypertensive adults. Under the context of the ATTICA Study, data from 1188 individuals, free of cardiovascular disease, but with defined high blood pressure levels (prehypertension) at baseline examination (during 2001-2002) were retrieved. In 2006, the 5-year follow-up of the study was performed, and 798 of the prehypertensive participants were allocated. In this work, incidence and determinants of developing hypertension were evaluated. The 5-year ageadjusted incidence of hypertension was 18.7% in men and 24.6% in women (P = 0.05); while almost one half of prehypertensive individuals at the age of 55-65 years developed hypertension, and approximately 6 out of 10 people over 65 years of age developed the disease. Multiple logistic regression analysis revealed that increased age (odds ratio [OR] per 1 year = 1.09, 95% confidence interval [CI] 1.07-1.12), male sex (OR = 0.40, 95% CI 0.21-0.68), high education status (OR per 1 year of school = 0.94, 95% CI 0.88-0.98), waist circumference (OR per 1 cm = 1.04, 95% CI 1.02-1.06) and C-reactive protein (OR per 1 mg/l = 1.12, 95% CI 1.05-1.20), were positively associated with the development of hypertension. Moreover, greater adherence to Mediterranean diet seems to protect only prehypertensive, with abdominal obesity patients prone to develop hypertension (OR = 0.94, 95% CI 0.90-0.98). Annual incidence of hypertension was roughly 4% in men and women. Older people, with low education, abdominal obesity, lower adherence to the Mediterranean diet, and increased inflammation, constitute a model of prehypertensive individuals that are prone to develop hypertension.

Hypoadiponectinemia is associated with blood pressure increase in obese insulin-resistant individuals

Adiponectin is a major adipocytokine and has been considered as an independent risk factor for arterial hypertension. Most studies on the subject have been restricted to biracial (white-black) and Asian groups. The present report examined whether adiponectin affects blood pressure in a sample of untreated obese Brazilians of multiethnic origin. Fasting plasma adiponectin and serum insulin were determined by radioimmunoassay. Insulin resistance was estimated by homeostatic model assessment of insulin resistance (HOMA-IR). Blood pressure was recorded using Dinamap 1846 (Critikon, Tampa, FL). Adiponectin was significantly lower in obese hypertensive individuals than in obese normotensive ones. Blood pressure, insulin, and HOMA-IR were significantly higher in obese hypertensive than in obese normotensive individuals. Plasma adiponectin was negatively associated with waist-to-hip ratio, blood pressure, insulin, and HOMA-IR. The comparison of obese individuals who markedly differed in their HOMA-IR (> vs <or=2.71) showed that the association of adiponectin and blood pressure remained significant only in obese insulin-resistant individuals, whose adiponectin showed a positive association with high-density lipoprotein cholesterol. Stepwise regression analysis revealed that HOMA-IR, adiponectin, body mass index, and age independently affected the risk for increased systolic blood pressure, with HOMA-IR the strongest of them all. Finally, when patients were stratified into tertiles of HOMA-IR and further classified according to the 50th percentile of adiponectin (<or= vs >6. 5 microg/mL), a 3 x 2 analysis of variance showed an independent contribution of adiponectin in the variation of mean arterial pressure. These results support the notion that HOMA-IR and adiponectin independently predict blood pressure variation in obese insulin-resistant Brazilians.

Cardiac energy metabolism in obesity

Obesity results in marked alterations in cardiac energy metabolism, with a prominent effect being an increase in fatty acid uptake and oxidation by the heart. Obesity also results in dramatic changes in the release of adipokines, such as leptin and adiponectin, both of which have emerged as important regulators of cardiac energy metabolism. The link among obesity, cardiovascular disease, lipid metabolism, and adipokine signaling is complex and not well understood. However, optimizing cardiac energy metabolism in obese subjects may be one approach to preventing and treating cardiac dysfunction that can develop in this population. This review discusses what is presently known about the effects of obesity and the impact adipokines have on cardiac energy metabolism and insulin signaling. The clinical implications of obesity and energy metabolism on cardiac disease are also discussed.