The effects of obesity and non-pharmacological weight loss on vascular and ventricular function and structure

New insights on the association of weight loss with the reduction in carotid intima-media thickness among patients with obesity: an updated systematic review and meta-analysis

OBJECTIVES

Carotid intima-media thickness (CIMT) is a noninvasive marker of atherosclerosis, a typical pathologic process underlying cardiovascular diseases (CVDs). It is essential to explore the relationships between weight loss and the reduction of CIMT.

STUDY DESIGN

This was an updated systematic review and meta-analysis.

METHODS

A systematic literature search was conducted to collect relevant clinical trials. The pooled results of meta-analyses were assessed by weighted mean difference (WMD) and the corresponding 95 % confidence interval (95% CI).

RESULTS

Thirty-three articles involving 2273 participants were collected in this meta-analysis. Among all participants with obesity, the pooled mean of weight loss was -23.26 kg (95% CI: -27.71 to -18.81), and the pooled mean change of CIMT was -0.06 mm (95% CI: -0.08 to -0.04). Compared with Non-surgical interventions, Surgical ones could lead to much higher weight loss (Pbetween groups < 0.001). A more significant CIMT reduction was identified among Surgical intervention patients than among Non-surgical intervention participants (Pbetween groups < 0.001).

CONCLUSIONS

Effective interventions, especially Surgical interventions, could reduce the weight of patients with obesity, followed by the decline of CIMT, which might further disturb atherosclerosis progression and lower CVD risk.

Association of adiposity indices with prehypertension among Chinese adults: A cross-sectional study

The association of adiposity indices with prehypertension remains unclear in the Chinese non-hypertensive population. This study aimed to compare the association of adiposity indices, including waist circumference (WC), waist-to-height ratio, body roundness index (BRI), a body shape index (ABSI), and conicity index (CI), and prehypertension in the Chinese population. We recruited 61 475 participants from a population-based screening project in Guangdong province, China. Multiple logistic regression analyses were performed to detect the association between the six adiposity indices and prehypertension. Receiver operator characteristic curve (ROC) analysis was used to evaluate the predictive values of adiposity indices to prehypertension. The individuals were divided into two categories by blood pressure (BP) levels: normotension (<120/80 mmHg) and prehypertension (120-139/80-89 mmHg). A total of 33 233 people had prehypertension, with a prevalence of 54.04% and 42% males. Both logistics regression models presented a positive association between each adiposity index and prehypertension (p < .05), except for ABSI. The body mass index (BMI) was slightly more correlated with prehypertension than any other index. The standardized ORs for the six indices were 1.392, 1.361, 1.406, 1.039, 1.372, and 1.151, respectively. Compared to other adiposity indices, the WC had a significantly higher area under the curve (AUC) for predicting prehypertension (AUC: .619, sensitivity: 57%, specificity: 60.6%). In conclusion, WC and BMI might be the best indicators for prehypertension. Increasing evidence supports avoiding obesity as a preferred primary prevention strategy for prehypertension while controlling other major hypertension risk factors.

Association Between Weight Change and Increased Likelihood of Abdominal Aortic Calcification Among Men

OBJECTIVE

We aimed to explore the effect of weight change on abdominal aortic calcification (AAC) among men.

METHODS

Data were obtained from the 2013 to 2014 National Health and Nutrition Examination Survey (NHANES). Self-reported cardiovascular disease patients were excluded. Lateral spine images were used to quantify AAC score and severe AAC was defined as a AAC score greater than 6. Weight change over a 10-year period was defined as long-term weight change, and weight change over a 1-year period was defined as short-term weight change. The relationship between long-term and short-term weight change with AAC grade was estimated by using multivariable regression analysis and subgroup analysis.

RESULTS

After adjusting for covariates, weight gain, especially severe weight gain (> 10 kg), was associated with increased likelihood of AAC and severe AAC both in the short term (1 year) and long term (10 years) among men when compared to stable weight change, while long-term weight loss could also lead to an increased likelihood of AAC and severe AAC.

CONCLUSION

Stable body weight might be a predictor of a lower risk of AAC and severe AAC among men in the long term and short term.

Obesity, arterial function and arterial structure - a systematic review and meta-analysis

OBJECTIVE

Obesity is an established risk factor for cardiovascular disease. The mechanisms by which obesity affects cardiovascular risk have not been fully elucidated. This paper reports a comprehensive systematic review and meta-analysis on obesity and two key aspects of vascular health using gold-standard non-invasive measures - arterial endothelial function (brachial flow-mediated dilatation) and subclinical atherosclerosis (carotid intima-media thickness).

METHODS

Electronic searches for 'Obesity and flow-mediated dilatation' and 'Obesity and intima-media thickness' were performed using Ovid Medline and Embase databases. A meta-analysis was undertaken for brachial flow-mediated dilatation and carotid intima-media thickness to obtain pooled estimates for adults with obesity and those with healthy weight.

RESULTS

Of the 5,810 articles retrieved, 19 studies on flow-mediated dilatation and 19 studies on intima-media thickness were included. Meta-analysis demonstrated that obesity was associated with lower flow-mediated dilatation (-1.92 % [95% CI -2.92, -0.92], P = 0.0002) and greater carotid intima-media thickness (0.07 mm [95% CI 0.05, 0.08], P < 0.0001).

CONCLUSIONS

Obesity is associated with poorer arterial endothelial function and increased subclinical atherosclerosis, consistent with these aspects of vascular health at least partially contributing to the increased risk of cardiovascular events in adults with obesity. These estimated effect sizes will enable vascular health benefits in response to weight loss treatment to be put in greater perspective, both in the research setting and potentially also clinical practice.

Weight loss and carotid intima-media thickness-a meta-analysis

OBJECTIVE

Obesity is a risk factor for clinical cardiovascular disease, putatively via increased burden of atherosclerosis. It remains contentious as to whether weight loss in people with obesity is accompanied by a reduction in intima-media thickness, a noninvasive marker of subclinical atherosclerosis, consistent with a lowering of risk of cardiovascular events.

METHODS

A systematic literature search was performed to identify all surgical and nonsurgical weight loss interventions that reported intima-media thickness. A meta-analysis was undertaken to obtain pooled estimates for change in intima-media thickness.

RESULTS

From the 3,197 articles screened, 9 studies were included in the meta-analysis, with a total of 393 participants who lost an average of 16 kg (95% CI 9.4-22.5) of body weight over an average follow-up of 20 months. The pooled mean change in carotid intima-media thickness was -0.03 mm (95% CI -0.05 to -0.01), which was similar between surgical and nonsurgical interventions.

CONCLUSIONS

In people with obesity, weight loss was associated with a reduction in carotid intima-media thickness, consistent with a lowering in risk of cardiovascular events.

The Influence of Known Genetic Variants on Subclinical Cardiovascular Outcomes in Childhood

Background—

Genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) for subclinical cardiovascular outcomes in adults. We examined the influence of these variants on the same outcomes in childhood.

Methods and Results—

In a population-based prospective cohort study among 4137 children, we examined the associations of SNPs, individually and incorporated in genetic risk scores, which were identified in adults for cardiac (2 SNPs for left ventricular end-diastolic diameter and 5 SNPs for aortic root diameter) and blood pressure outcomes (29 SNPs for systolic and diastolic blood pressure, 22 SNPs for mean arterial pressure, and 10 SNPs for pulse pressure) with the same outcomes in children (median age of 6.0 years [95% range, 4.5–8.7]). Weighted and unweighted risk scores for aortic root diameter were associated with childhood aortic root diameter (difference per additional average risk allele 0.09 mm [95% CI: 0.05, 0.13]). Weighted and unweighted risk scores for pulse pressure were associated with childhood pulse pressure (difference per additional average risk allele 0.22 mm Hg [95% CI: 0.08, 0.35] and 0.18 mm Hg [95% CI: 0.05, 0.31], respectively), but not with childhood systolic or diastolic blood pressure or mean arterial pressure. The risk scores for blood pressure and mean arterial pressure were not associated with any of the childhood blood pressure outcomes.

Conclusions—

Genetic risk scores based on SNPs for aortic root diameter and pulse pressure in adults are associated with the same outcomes in children. SNPs related to cardiovascular outcomes in adulthood at least partly influence cardiovascular development from early life onwards.

Successful weight reduction improves left ventricular diastolic function and physical performance in severe obesity

Obesity and the metabolic syndrome (MetS) are risk factors for left ventricular diastolic dysfunction (LVDD). However, little is known about the impact of successful weight reduction (WR) on diastolic function and physical performance.Obese subjects (øBMI 40.2 ± 8.6 kg/m(2)) underwent a 1-year WR program comprising diet and lifestyle components. Echocardiography and exercise capacity (6-minute walk) were performed at baseline and after 1 year. The distribution of weight reduction was split at the sample median and subjects were dichotomized in "successful WR" (% WR ≥ median, corresponding to a weight loss of 8%) and "failed-WR" (% WR < median).From a total of 188 obese subjects, 71 had LVDD at baseline. Obese patients with successful WR improved their MetS alterations, including fasting glucose, insulin, lipids, adipokines, blood pressure levels, and epicardial fat thickness. The same was not true for obesity with failed WR. Subjects with successful WR demonstrated significant improvement in echocardiographic LVDD parameters (median [interquartile range]): Δe' (2,5 [-1.0, 4.7], P < 0.01), Δe'/a' (0.34 [0.07, 079], P < 0.01), ΔE/e' (-1.14 [-2.72, -0.54], P < 0.05), ΔE/A (0.08 [-0.04, 0.26], P < 0.05), ΔArd-Ad (-28 [-54, -4], P < 0.01), and 6-minute walk distance (65 [19, 135], P < 0.01). Improvement of ≥ 2 LVDD criteria was accomplished in 30% of subjects with WR versus 10% without (P = 0.009). Using multivariable regression analysis, reduction of epicardial fat thickness was particularly predictive for the improvement of diastolic function.In summary, in severe obesity, successful long-term WR was associated with improved LV diastolic function and exercise capacity.

Weight loss improves fasting flow-mediated vasodilation in adults: a meta-analysis of intervention studies

BACKGROUND

Obesity is associated with vascular endothelial dysfunction. Effects of weight loss on endothelial function are however not clear. Therefore, we performed a meta-analysis to quantify effects of weight loss on flow-mediated vasodilation (FMD) of the brachial artery, a measurement of endothelial function.

METHODS

Studies with experimental (RCTs) and quasi-experimental designs published before June 2014 were identified by a systematic search. Changes in FMD were defined as the difference between measurements before and after the study. For RCTs, changes were corrected for those in the no-weight loss control group. Summary estimates of weighted mean differences (WMDs) in FMD and 95% confidence intervals (CIs) were calculated using random-effect meta-analyses. The impact of subject characteristics, type of weight-loss treatment, and dietary composition on changes in FMD was also investigated.

RESULTS

Four RCTs involving 265 subjects were included. Weight loss increased FMD vs. control by 3.29% (95% CI: 0.98-5.59%; P = 0.005; mean weight loss: 8.6 kg). A total of 1517 subjects participated in 33 studies with 49 relevant study arms. It was estimated that each 10 kg decrease in body weight increased fasting FMD by 1.11% (95% CI: 0.47-1.76%; P = 0.001). Effects were more pronounced when participants had coexisting obesity-related morbidities. Also, effects may be larger when subjects received low-fat diets or weight-reduction regimens including exercise therapy or weight-loss medication.

CONCLUSION

Weight loss significantly improves fasting FMD in adults, which is a risk marker for cardiovascular disease. Effects may depend on subject characteristics, type of weight-loss treatment, and dietary composition.

Aerobic exercise and weight loss reduce vascular markers of inflammation and improve insulin sensitivity in obese women

OBJECTIVES

To examine the relationships between plasma and tissue markers of systemic and vascular inflammation and obesity and insulin resistance and determine the effects of aerobic exercise training plus weight loss (AEX+WL) and weight loss (WL) alone on these biomarkers.

DESIGN

Prospective controlled study.

SETTING

Veterans Affairs Medical Center and University research setting.

PARTICIPANTS

Overweight and obese sedentary postmenopausal women (N = 77).

INTERVENTIONS

Six months, 3 d/wk AEX+WL (n = 37) or WL (n = 40).

MEASUREMENTS

Total-body dual-energy X-ray absorptiometry, abdominal computed tomography, hyperinsulinemic-euglycemic clamps (a criterion standard method of assessing insulin sensitivity), adipose tissue biopsies (n = 28), and blood for homeostasis model assessment-insulin resistance, and soluble forms of intracellular adhesion molecule 1 (sICAM-1) and vascular cell adhesion molecule 1 (sVCAM-1), C-reactive protein (CRP), and serum amyloid A (SAA).

RESULTS

Body weight (P < .001), percentage of fat (P < .001), visceral fat (P < .005), triglyceride levels (P < .001), and systolic blood pressure decreased comparably after WL and AEX+WL (P = .04). Maximal oxygen consumption increased 16% after AEX+WL (P < .001). Insulin resistance decreased in both groups (P = .005). Glucose utilization according to the clamp increased 10% (P = .04) with AEX+WL and 8% with WL (P = .07). AEX+WL decreased CRP by 29% (P < .001) and WL by 21% (P = .02). SAA levels decreased twice as much after AEX+WL (-19%, P = .02) as after WL (-9%, P = .08). Plasma sICAM-1 and sVCAM-1 levels did not change, but women with the greatest reduction in plasma sICAM-1 levels had the greatest reductions in fasting glucose (P = .02), insulin (P = .02), and insulin resistance (P = .004). Gluteal ICAM messenger ribonucleic acid levels decreased 27% after AEX+WL (P = .02) and did not change after WL.

CONCLUSION

Obesity and insulin resistance worsen markers of systemic and vascular inflammation. A reduction in plasma sICAM-1 is important to improve insulin sensitivity. CRP, SAA, and tissue ICAM decrease with exercise and weight loss, suggesting that exercise training is a necessary component of lifestyle modification in obese postmenopausal women.

Endothelial function and weight loss: comparison of low-carbohydrate and low-fat diets

OBJECTIVE

The effect of weight loss on obesity-associated endothelial dysfunction is not clear because of conflicting data, demonstrating both improvement and no change in endothelial function after weight loss in obese subjects. A 2-year prospective study (n = 121) was conducted to examine: (1) the effect of obesity and weight loss (either a low-carbohydrate or and low-fat diet) on flow mediated vasodilatation (FMD), a measure of endothelial function.

DESIGN AND METHODS

Participants reduced body weight by 7.1% ± 4.4%, 8.7% ± 6.8%, 7.1% ± 7.8%, and 4.1% ± 7.7% at 3, 6, 12, and 24 months, respectively with no significant differences between the low-fat and low-carbohydrate groups.

RESULTS

Endothelial function was inversely correlated with waist circumference, triglyceride level, and directly correlated with leptin in obese persons prior to weight loss. These weight losses did not confer any improvements in FMD. There were no differences between the low-fat and low-carbohydrate diets in FMD at any time point. At 6 months (r = 0.26, P = 0.04) and 1 year (r =0.28, P = 0.03), there were positive correlations between change in FMD and change in leptin but not at 2 years.

CONCLUSION

There was no significant improvement in endothelial function after 7.1% ± 7.8% weight loss at 1 year and 4.1% ± 7.7% at 2 years, achieved by either a low carbohydrate or a low fat diet.

Increased carotid intima-media thickness and reduced distensibility in human class III obesity: independent and differential influences of adiposity and blood pressure on the vasculature

Carotid intima-media-thickness (cIMT) and carotid distensibility (distensibility), structural and functional properties of carotid arteries respectively, are early markers, as well as strong predictors of cardiovascular disease (CVD). The characteristic of these two parameters in individuals with BMI>40.0 kg/m(2) (Class III obesity), however, are largely unknown. The present study was designed to document cIMT and distensibility in this population and to relate these to other factors with established association with CVD in obesity. The study included 96 subjects (65 with BMI>40.0 kg/m(2) and 31, age- and gender-matched, with BMI of 18.5 to 30.0 kg/m(2)). cIMT and distensibility were measured by non-invasive high resolution ultrasonography, circulatory CD133(+)/KDR(+) angiogenic cells and endothelial microparticles (EMP) by flow cytometry, and plasma levels of adipokines, growth factors and cytokines by Luminex immunoassay kits. The study results demonstrated increased cIMT (0.62±0.11 mm vs. 0.54±0.08 mm, P = 0.0002) and reduced distensibility (22.52±10.79 10(-3)kpa(-1)vs. 29.91±12.37 10(-3)kpa(-1), P<0.05) in individuals with BMI>40.0 kg/m(2). Both cIMT and distensibility were significantly associated with traditional CVD risk factors, adiposity/adipokines and inflammatory markers but had no association with circulating angiogenic cells. We also demonstrated, for the first time, elevated plasma EMP levels in individuals with BMI>40.0 kg/m(2). In conclusion, cIMT is increased and distensibility reduced in Class III obesity with the changes predominantly related to conventional CVD risk factors present in this condition, demonstrating that both cIMT and distensibility remain as CVD markers in Class III obesity.

Effects of an intensive behavioral weight loss intervention consisting of caloric restriction with or without physical activity on common carotid artery remodeling in severely obese adults

OBJECTIVE

Obesity increases cardiovascular disease risk and adversely affects vascular structure and function. Few studies have evaluated the vascular effects of non-surgical weight reduction in the severely obese. We hypothesized that weight loss and improvements in cardiometabolic factors would reduce common carotid artery intima-media thickness (CIMT) and inter-adventitial diameter (AD) in severely obese adults.

METHODS

We performed carotid ultrasound and measured cardiometabolic factors in 90 severely obese participants (body mass index (BMI)≥35 kg/m(2), age 30-55) at baseline and 6 months in a randomized clinical trial of dietary intervention with (n=45) or without (n=45) physical activity.

RESULTS

The achieved weight loss (mean=8%) did not differ significantly by intervention group (P=0.10) and resulted in a 0.07 mm mean decrease in AD (P=0.001). AD change was positively correlated with changes in BMI, waist circumference, abdominal visceral and subcutaneous fat, and body fat mass, and AD decreased more in men (P<0.05 for all). After multivariable adjustment, changes in BMI (P=0.03) and abdominal subcutaneous fat (P=0.04) were significant determinants of AD change. Although CIMT did not decrease significantly overall (-0.008 mm, P=0.16), individuals who lost at least 5% of their body weight experienced a significant mean reduction in CIMT of 0.02 mm (P=0.002). CIMT change was positively correlated with changes in BMI, waist circumference, fat-free mass, leptin, and insulin (P<0.05 for all). After multivariable adjustment, insulin reduction remained a significant determinant of CIMT decrease (P=0.03).

CONCLUSION

A 6 month intensive behavioral intervention can significantly reverse metabolic and vascular abnormalities in severely obese adults.

Longitudinal displacement of the carotid wall and cardiovascular risk factors: associations with aging, adiposity, blood pressure and periodontal disease independent of cross-sectional distensibility and intima-media thickness

The recently discovered longitudinal displacement of the common carotid arterial wall (i.e., the motion along the same plane as the blood flow), may be associated with incident cardiovascular events and represents a novel and relevant clinical information. At present, there have only been a few studies that have been conducted to investigate this longitudinal movement. We propose here a method to assess noninvasively the wall bi-dimensional (two-dimensional [2-D], cross-sectional and longitudinal) motion and present an original approach that combines a robust speckle tracking scheme to guidance by minimal path contours segmentation. Our method is well suited to large clinical population studies as it does not necessitate strong imaging prerequisites. The aim of this study is to describe the association between the longitudinal displacement of the carotid arterial wall and cardiovascular risk factors, among which periodontal disease. Some 126 Indigenous Australians with periodontal disease, an emerging risk factor, and 27 healthy age- and sex-matched non-indigenous control subjects had high-resolution ultrasound scans of the common carotid artery. Carotid intima-media thickness and arterial wall 2-D motion were then assessed using our method in ultrasound B-mode sequences. Carotid longitudinal displacement was markedly lower in the periodontal disease group than the control group (geometric mean (IQR): 0.15 mm (0.13) vs. 0.42 mm (0.30), respectively; p < 0.0001), independent of cardiovascular risk factors, cross-sectional distensibility and carotid intima-media thickness (p < 0.0001). A multivariable model indicated that the strongest correlates of carotid longitudinal displacement in adults with periodontal disease were age (β-coefficient = -.235, p = .03), waist (β-coefficient = -.357, p = 0.001), and pulse pressure (β-coefficient = .175, p = 0.07), independent of other cardiovascular risk factors, cross-sectional distensibility and pulse wave velocity. Carotid longitudinal displacement, estimated with our approach, is impaired in the periodontal disease group, independent of established cardiovascular risk factors and other noninvasive measures of arterial stiffness, and may represent an important marker of cardiovascular risk.

Reductions in arterial stiffness with weight loss in overweight and obese young adults: potential mechanisms

OBJECTIVE

Arterial stiffness decreases with weight loss in overweight/obese young adults. We aimed to determine the mechanisms by which this occurs.

METHODS

We evaluated carotid-femoral pulse wave velocity (cfPWV) and brachial-ankle pulse wave velocity (baPWV) in 344 young adults (23% male, BMI 25-40 kg/m(2)) at baseline, 6, and 12 months in a behavioral weight loss intervention. Linear mixed models were used to evaluate associations between weight loss and arterial stiffness and to examine whether improvements in obesity-related factors explained these associations.

RESULTS

At 6 months (7% mean weight loss), there was a significant median decrease of 47.5 cm/s in cfPWV (p < 0.0001) and a mean decrease of 11.7 cm/s in baPWV (p = 0.049). At 12 months (6% mean weight loss), only cfPWV remained reduced. In models adjusting for changes in mean arterial pressure and obesity-related factors, changes in BMI (p = 0.01) and common carotid artery diameter (p = 0.003) were positively associated with change in cfPWV. Reductions in heart rate (p < 0.0001) and C-reactive protein (p = 0.02) were associated with reduced baPWV and accounted for the association between weight loss and reduced baPWV.

CONCLUSIONS

Weight loss is associated with reduced cfPWV independently of changes in established hemodynamic and cardiometabolic risk factors, but its association with reduced baPWV is explained by concurrent reductions in heart rate and inflammation.

Impact of exercise training on arterial wall thickness in humans

Thickening of the carotid artery wall has been adopted as a surrogate marker of pre-clinical atherosclerosis, which is strongly related to increased cardiovascular risk. The cardioprotective effects of exercise training, including direct effects on vascular function and lumen dimension, have been consistently reported in asymptomatic subjects and those with cardiovascular risk factors and diseases. In the present review, we summarize evidence pertaining to the impact of exercise and physical activity on arterial wall remodelling of the carotid artery and peripheral arteries in the upper and lower limbs. We consider the potential role of exercise intensity, duration and modality in the context of putative mechanisms involved in wall remodelling, including haemodynamic forces. Finally, we discuss the impact of exercise training in terms of primary prevention of wall thickening in healthy subjects and remodelling of arteries in subjects with existing cardiovascular disease and risk factors.

Effect of altering dietary n-6:n-3 PUFA ratio on cardiovascular risk measures in patients treated with statins: a pilot study

Increasing dietary n-3 PUFA decreases the risk of CHD. Since n-6 PUFA compete with n-3 PUFA for common metabolic enzymes, the n-6:n-3 ratio intake rather than the n-3 PUFA intake levels per se may be critical. We aimed to examine whether altering the n-6:n-3 ratio affects cardiovascular risk factors in hypercholesterolaemic patients on lipid management with statins. Adhering to a randomised, crossover study design, patients on statins (n 11) were placed on one of two dietary interventions (Diet high-ratio (HR) - n-6:n-3 = 30:1 or Diet low-ratio (LR) - n-6:n-3 = 1·7:1) for 4 weeks followed after an 8-week washout period by the alternate diet. Foods enriched with n-3 or n-6 PUFA were delivered to each patient, who were given clear guidance on consumption expectations for the study. Measures of lipid profile, blood pressure and vascular function were determined. Diet LR significantly reduced body weight, LDL-cholesterol, high-sensitivity C-reactive protein, blood pressure and the apoA-1:apoB ratio. While Diet HR trended towards a similar cardioprotective profile, most of the parameters examined did not reach statistical significance. A direct comparison between diets demonstrated no significant superiority of Diet LR over Diet HR. These results suggest that a dietary intervention focused on n-6 and n-3 fatty acids may improve cardiovascular risk factors in patients over and above standard lipid management, but there is no significant advantage of a low n-6:n-3 ratio diet when compared to a high-ratio diet.

Comparing effects of a low-energy diet and a high-protein low-fat diet on sexual and endothelial function, urinary tract symptoms, and inflammation in obese diabetic men

INTRODUCTION

Abdominal obesity and type 2 diabetes mellitus are associated with sexual and endothelial dysfunction, lower urinary tract symptoms (LUTS), and chronic systemic inflammation.

AIM

To determine the effects of diet-induced weight loss and maintenance on sexual and endothelial function, LUTS, and inflammatory markers in obese diabetic men.

MAIN OUTCOME MEASURES

Weight, waist circumference (WC), International Index of Erectile Function (IIEF-5) score, Sexual Desire Inventory (SDI) score, International Prostate Symptom Scale (IPSS) score, plasma fasting glucose and lipids, testosterone, sex hormone binding globulin (SHBG), inflammatory markers (high-sensitivity C-reactive protein [CRP] and interleukin-6 [IL-6]) and soluble E-selectin, and brachial artery flow-mediated dilatation (FMD) were measured at baseline, 8 weeks, and 52 weeks.

METHODS

Over 8 weeks, 31 abdominally obese (body mass index ≥ 30 kg/m(2) , WC ≥ 102 cm), type 2 diabetic men (mean age 59.7 years) received either a meal replacement-based low-calorie diet (LCD) ∼1,000 kcal/day (N = 19) or low-fat, high-protein, reduced-carbohydrate (HP) diet (N = 12) prescribed to decrease intake by ∼600 kcal/day. Subjects continued on, or were switched to, the HP diet for another 44 weeks.

RESULTS

At 8 weeks, weight and WC decreased by ∼10% and ∼5% with the LCD and HP diet, respectively. Both diets significantly improved plasma glucose, low-density lipoprotein (LDL), SHBG, IIEF-5, SDI and IPSS scores, and endothelial function (increased FMD, reduced soluble E-selectin). Erectile function, sexual desire, and urinary symptoms improved by a similar degree with both diets. CRP and IL-6 decreased with the HP diet. At 52 weeks, reductions in weight, WC, and CRP were maintained. IIEF-5, SDI, and IPSS scores improved further.

CONCLUSIONS

Diet-induced weight loss induces rapid improvement of sexual, urinary, and endothelial function in obese diabetic men. A high-protein, carbohydrate-reduced, low-fat diet also reduces systemic inflammation and sustains these beneficial effects to 1 year.

The role of dietary fatty acids in predicting myocardial structure in fat-fed rats

Background

Obesity increases the risk for development of cardiomyopathy in the absence of hypertension, diabetes or myocardial ischemia. Not all obese individuals, however, progress to heart failure. Indeed, obesity may provide protection from cardiovascular mortality in some populations. The fatty acid milieu, modulated by diet, may modify obesity-induced myocardial structure and function, lending partial explanation for the array of cardiomyopathic phenotypy in obese individuals.

Methods

Adult male Sprague-Dawley rats were fed 1 of the following 4 diets for 32 weeks: control (CON); 50% saturated fat (SAT); 40% saturated fat + 10% linoleic acid (SAT+LA); 40% saturated fat + 10% α-linolenic acid (SAT+ALA). Serum leptin, insulin, glucose, free fatty acids and triglycerides were quantitated. In vivo cardiovascular outcomes included blood pressure, heart rate and echocardiographic measurements of structure and function. The rats were sacrificed and myocardium was processed for fatty acid analysis (TLC-GC), and evaluation of potential modifiers of myocardial structure including collagen (Masson's trichrome, hydroxyproline quantitation), lipid (Oil Red O, triglyceride quantitation) and myocyte cross sectional area.

Results

Rats fed SAT+LA and SAT+ALA diets had greater cranial LV wall thickness compared to rats fed CON and SAT diets, in the absence of hypertension or apparent insulin resistance. Treatment was not associated with changes in myocardial function. Myocardial collagen and triglycerides were similar among treatment groups; however, rats fed the high-fat diets, regardless of composition, demonstrated increased myocyte cross sectional area.

Conclusions

Under conditions of high-fat feeding, replacement of 10% saturated fat with either LA or ALA is associated with thickening of the cranial LV wall, but without concomitant functional changes. Increased myocyte size appears to be a more likely contributor to early LV thickening in response to high-fat feeding. These findings suggest that myocyte hypertrophy may be an early change leading to gross LV hypertrophy in the hearts of "healthy" obese rats, in the absence of hypertension, diabetes and myocardial ischemia.

Severe obesity is associated with impaired arterial smooth muscle function in young adults

The degree of arterial dilatation induced by exogenous nitrates (nitrate-mediated dilatation, NMD) has been similar in obese and normal-weight adults after single high-dose glyceryl trinitrate (GTN). We examined whether NMD is impaired in obesity by performing a GTN dose-response study, as this is a potentially more sensitive measure of arterial smooth muscle function. In this cross-sectional study, subjects were 19 obese (age 31.0 ± 1.2 years, 10 male, BMI 44.1 ± 2.1) and 19 age- and sex-matched normal-weight (BMI 22.4 ± 0.4) young adults. Blood pressure (BP), triglycerides, high-density lipoprotein (HDL), and low-density lipoprotein (LDL)-cholesterol, glucose, insulin, high-sensitivity C-reactive protein (hs-CRP), carotid intima-media thickness (CIMT), and flow-mediated dilatation (FMD) were measured. After incremental doses of GTN, brachial artery maximal percent dilatation (maximal NMD) and the area under the dose-response curve (NMD AUC) were calculated. Maximal NMD (13.4 ± 0.9% vs. 18.3 ± 1.1%, P = 0.002) and NMD AUC (54,316 ± 362 vs. 55,613 ± 375, P = 0.018) were lower in obese subjects. The obese had significantly higher hs-CRP, insulin, and CIMT and lower HDL-cholesterol. Significant bivariate associations existed between maximal NMD or NMD AUC and BMI-group (r = -0.492, P = 0.001 or r = -0.383, P = 0.009), hs-CRP (r = -0.419, P = 0.004 or r = -0.351, P = 0.015), and HDL-cholesterol (r = 0.374, P = 0.01 or r = 0.270, P = 0.05). On multivariate analysis, higher BMI-group remained as the only significant determinant of maximal NMD (r² = 0.242, β = -0.492, P = 0.002) and NMD AUC (r² = 0.147, β = -0.383, P = 0.023). In conclusion, arterial smooth muscle function is significantly impaired in the obese. This may be important in their increased cardiovascular risk.

Influence of glycemic control on the development of diabetic cardiovascular and kidney disease

Diabetes mellitus leads to the development of a host of micro- and macrovascular complications, which collectively lead to substantial morbidity and mortality. Among the microvascular complications of diabetes, diabetic kidney disease is the most common. Macrovascular complications from diabetes lead to a 2- to 4-fold increase in the incidence of cardiovascular disease and up to twice the mortality from cardiovascular causes as compared with nondiabetic individuals. This article discusses the various drug classes used to treat diabetes mellitus, and reviews the current clinical evidence linking glycemic control using these drug classes on diabetic kidney and cardiovascular disease.

Human obesity relationship with Ad36 adenovirus and insulin resistance

OBJECTIVES

Infection with specific pathogens may lead to increased adiposity: a specific adiposity-promoting effect of Ad36 human adenovirus, without the involvement of neurological mechanisms, was reported. The aim of this study is to investigate whether non-diabetic patients with earlier Ad36 infection show greater degrees of overweight obesity, of Insulin Resistance (IR), assessed by homoeostasis-model assessment (HOMA), and/or of other related factors. Moreover, the relationship, if any, among these factors and an earlier Ad36 infection, and the hypothesis of a mechanism involving IR are investigated.

SUBJECTS

Ad36 seropositivity is assessed in 68 obese and 135 non-obese subjects, along with body composition, HOMA and laboratory investigations.

RESULTS

Age, body mass index (BMI), waist-hip ratio, blood pressure, insulin, HOMA and triglycerides are significantly greater in the Ad36 seropositive group. Ad36 seropositivity, along with HOMA and total cholesterol, explains BMI variance. No Ad36 seropositivity effect to HOMA could be envisaged by the same statistical model.

CONCLUSION

A significant association of Ad36 seropositivity with obesity and with essential hypertension in human beings is suggested by our study; this association is mostly significant in women. Our results do not support that any Ad36 adipogenic adenovirus effect is operating in human obesity through an insulin-resistance-related mechanism. Ad36 seropositive status could also be a hallmark of a clinical-metabolic profile possibly preceding obesity and diabetes in non-obese patients.

Vasoreactivity is rapidly improved in obese subjects after gastric bypass surgery

BACKGROUND

Obesity is associated with increased risk of cardiovascular disease. We investigated vasoreactivity in conduit and resistance arteries in morbidly obese subjects, and the effect of weight loss after gastric bypass surgery.

METHODS

A total of 19 obese subjects (body mass index (BMI): 43.8+/-3.1 kg m(-2), 75% female, mean age 41 years) were investigated before surgery and after 1 and 12 months of surgery. Nineteen non-obese controls matched for age and gender were examined. Vasoreactivity was evaluated by ultrasound to measure flow-mediated dilation (FMD, evaluating a conduit vessel) and pulse-wave analysis with terbutaline provocation (change in reflectance index (RI), evaluating resistance vessels).

RESULTS

Before surgery, the obese showed a low change in RI (18+/-12 vs 37+/-15% in controls, P=0.0001), but not significantly regarding FMD (7.9+/-6.4 vs 8.9+/-5.4% in controls). Surgery resulted in a weight loss of 9% at 1 month and 30% at 1 year. Change in RI markedly improved to 36+/-12% at 1 month (P=0.0001 vs baseline) and further to 44+/-11% at 1 year (P=0.014 vs 1 month). FMD did not change significantly. Heart rate and brachial artery diameter were reduced, with no significant change in blood pressure. The improvement in resistance vessel vasodilation, estimated as change in RI, was not correlated to changes in weight or measures of glucose and lipid metabolism.

CONCLUSIONS

Obese patients showed impaired vasoreactivity in resistance arteries that was normalized already 1 month after gastric bypass surgery. The basis for this remarkable outcome, not significantly related to changes in body weight and metabolic variables, remains to be clarified.

Postprandial vascular reactivity in obese and normal weight young adults

As humans spend a significant amount of time in the postprandial state, we examined whether vascular reactivity (a key indicator of cardiovascular health) was different after a high-fat meal in 11 obese (median BMI 46.4, age 32.1 +/- 6.3 years, 7 men) and 11 normal weight (median BMI 22.6) age- and sex-matched controls. At baseline and 1 and 3 h postmeal, blood pressure (BP), heart rate (HR), reactive hyperemia peripheral artery tonometry (RH-PAT) index, radial augmentation index adjusted for HR (AIx75), brachial pulse wave velocity (PWV(b)), glucose, insulin, total and high-density lipoprotein (HDL) cholesterol, and triglycerides were measured. Brachial flow-mediated dilatation (FMD) and, by venous plethysmography, resting and hyperemic forearm blood flows (FBFs) were measured at baseline and 3 h. At baseline, obese subjects had higher systolic BP, HR, resting FBF, insulin and equivalent FMD, RH-PAT, hyperemic FBF, AIx75, PWV(b), glucose, total cholesterol, triglycerides, and lower HDL cholesterol. In obese and lean subjects, FMD at baseline and 3 h was not significantly different (6.2 +/- 1.7 to 5.8 +/- 4.3% for obese and 4.7 +/- 4.1 to 4.3 +/- 3.9% for normal weight, P = 0.975 for group x time). The meal did not produce significant changes in RH-PAT, hyperemic FBF, and PWV(b) in either group (P > 0.1 for the effect of time and for group x time interactions). In conclusion, the vascular responses to a high-fat meal are similar in obese and normal weight young adults. An exaggerated alteration in postprandial vascular reactivity is thus unlikely to contribute importantly to the increased cardiovascular risk of obesity.

Maladaptive enlargement of the brachial artery in severe obesity is reversed with weight loss

Maladaptive peripheral arterial remodeling, which leads to large arteries with low shear stress, may be associated with increased cardiovascular risk. We tested the hypothesis that arterial enlargement in severe obesity represents maladaptive remodeling and that weight reduction would reverse this process. We evaluated brachial arterial diameter and flow using ultrasound in 244 severely obese patients (age 44 +/- 11 years, 80% female, body mass index (BMI) 46 +/- 9 kg/m) at baseline and in a group of 67 subjects who experienced weight loss at 1 year. Higher BMI was associated with larger brachial artery diameter (p = 0.01) and lower shear stress (p = 0.008), indicating maladaptive remodeling. Significant (> or = 10%) weight reduction was associated with a decrease in resting arterial diameter (-0.19 +/- 0.47 mm, p = 0.02) along with a trend toward increased shear stress. Decreased systemic inflammation was associated with weight loss-induced reverse remodeling of the brachial artery. Our findings demonstrate the presence of maladaptive arterial remodeling in advanced obesity that was ameliorated by significant weight loss.

Long-term successful weight loss improves vascular endothelial function in severely obese individuals

Obesity is associated with increased cardiovascular risk. Although short-term weight loss improves vascular endothelial function, longer term outcomes have not been widely investigated. We examined brachial artery endothelium-dependent vasodilation and metabolic parameters in 29 severely obese subjects who lost > or =10% body weight (age 45 +/- 13 years; BMI 48 +/- 9 kg/m(2)) at baseline and after 12 months of dietary and/or surgical intervention. We compared these parameters to 14 obese individuals (age 49 +/- 11 years; BMI 39 +/- 7 kg/m(2)) who failed to lose weight. For the entire group, mean brachial artery flow-mediated dilation (FMD) was impaired at 6.7 +/- 4.1%. Following sustained weight loss, FMD increased significantly from 6.8 +/- 4.2 to 10.0 +/- 4.7%, but remained blunted in patients without weight decline from 6.5 +/- 4.0 to 5.7 +/- 4.1%, P = 0.013 by ANOVA. Endothelium-independent, nitroglycerin-mediated dilation (NMD) was unaltered. BMI fell by 13 +/- 7 kg/m(2) following successful weight intervention and was associated with reduced total and low-density lipoprotein cholesterol, glucose, hemoglobin A(1c), and high-sensitivity C-reactive protein (CRP). Vascular improvement correlated most strongly with glucose levels (r = -0.51, P = 0.002) and was independent of weight change. In this cohort of severely obese subjects, sustained weight loss at 1 year improved vascular function and metabolic parameters. The findings suggest that reversal of endothelial dysfunction and restoration of arterial homeostasis could potentially reduce cardiovascular risk. The results also demonstrate that metabolic changes in association with weight loss are stronger determinants of vascular phenotype than degree of weight reduction.

Parity and carotid atherosclerosis in men and women: insights into the roles of childbearing and child-rearing

BACKGROUND AND PURPOSE

Parity appears to be associated with carotid atherosclerosis in women aged 45 years and older. Studying this association among younger women and men may provide insight into whether this association relates predominantly to childbearing or child-rearing.

METHODS

The association between parity and carotid atherosclerosis (intima-media thickness and presence of plaques) was assessed in a cohort consisting of 750 women and 1164 men, all with at least one traditional cardiovascular risk factor, aged 18 to 80 years of age. Traditional cardiovascular risk factors were also assessed, and the Framingham Risk Score calculated.

RESULTS

In age-adjusted analyses, the number of children was associated with adiposity, fasting glucose, 2-hour glucose, Framingham risk score, and carotid atherosclerosis in women, but not in men. Multivariate linear regression models indicate that the prevalence of plaques was increased by 15% (95% CI, 2 to 29) per child among women, and 0% (95% CI, -10 to 11) among men, after adjustment for age, socioeconomic and lifestyle factors (including waist circumference). The association between parity and carotid intima-media thickness was similar in younger and older women (P(Heterogeneity)=0.20).

CONCLUSIONS

A higher number of children is associated with increased carotid atherosclerosis in both younger and older women, but not among men. These findings indicate that childbearing, but not child-rearing, may be a risk factor for atherosclerosis, and suggest the potential importance of considering the number of children when assessing the level of cardiovascular risk in women.