Influence of leptin, adiponectin, and resistin on the association between abdominal adiposity and arterial stiffness

Effects of diet and/or low-intensity resistance exercise training on arterial stiffness, adiposity, and lean mass in obese postmenopausal women

BACKGROUND

Obesity and aging are associated with increased arterial stiffness as indicated by an increased pulse-wave velocity (PWV). We evaluated the independent and combined effects on PWV and body composition of a hypocaloric diet and low-intensity resistance exercise training (LIRET) with slow movement.

METHODS

Forty-one postmenopausal women (mean age, 54±6 years; body mass index (BMI), 33.8±0.5kg/m(2)) were randomly assigned to LIRET (n = 14), diet (n = 13), or diet + LIRET (n = 14) for 12 weeks. The women's PWV, mean arterial pressure (MAP), body composition by dual-en ergy x-ray absorptiometry (DXA), and plasma adipokine and insulin levels were measured before and after the interventions.

RESULTS

Body weight (P = 0.0001), trunk-fat mass (FM, P = 0.0001), and the serum concentration of leptin (P = 0.02 and P = 0.004) decreased similarly with diet and diet + LIRET, but not with LIRET alone. Leg lean mass (LM) decreased (P = 0.02) with diet, but did not change with diet + LIRET or with LIRET alone. Leg muscle strength increased similarly with LIRET (P = 0.001) and diet + LIRET (P = 0.0001), but did not change with diet alone. Brachial-ankle PWV (baPWV) decreased with diet (P = 0.04) and diet + LIRET (P = 0.01), whereas femoral-ankle PWV (legPWV) decreased only with diet (P = 0.01). Mean arterial pressure (MAP) decreased after LIRET (P = 0.03), diet (P = 0.04), and diet + LIRET (P = 0.004). Carotid-femoral PWV, serum adiponectin concentration, and insulin were not significantly affected by the interventions examined in the study. The reductions in baPWV and legPWV were correlated with one another (r = 0.73, P = 0.0001), and the reductions in legPWV and trunk FM were also correlated with one another (r = 0.36, P = 0.03).

CONCLUSIONS

A hypocaloric diet decreases baPWV mainly by reducing legPWV, and this reduction is related to the loss of truncal fat. Although LIRET alone does not affect PWV or body composition, LIRET combined with diet improves baPWV and muscle strength while preventing loss of lean body mass in obese postmenopausal women.

Abdominal obesity, body mass index, and hypertension in US adults: NHANES 2007-2010

BACKGROUND

Both abdominal obesity, defined as waist circumference (WC) ≥ 102 cm for men and WC ≥ 88 cm for women and increased body mass index (BMI; kg/m²) are known to be associated with hypertension. The aim of this study was to examine the independent and the combined relationship between abdominal obesity and increased BMI and hypertension by age, race, and gender in a national sample.

METHODS

This report is based on national level cross-sectional data for adults aged 18 years and older (11,145 participants) from the US National Health and Nutrition Examination Survey (NHANES) 2007-2010.

RESULTS

Abdominal obesity, after adjusting for BMI categories and other covariables, was independently associated with hypertension. That is, survey participants classified as abdominally obese had almost 50% increased odds of being hypertensive (odds ratio (OR) 1.51, 95% confidence interval (CI) 1.27-1.81) after controlling for BMI. After adjusting for covariables, the groups of individuals classified as abdominally obese and normal BMI; as abdominally obese and overweight; and abdominally obese and obese each had a progressive increase in the odds of hypertension when compared with individuals who had a normal BMI and no abdominal obesity (OR 1.81, 95% CI 1.28-2.57, OR 1.87, 95% CI 1.55-2.25, and OR 3.23, 95% CI 2.63-3.96, respectively).

CONCLUSIONS

Abdominal obesity is independently associated with hypertension after adjusting for BMI. After adjusting for covariables and parameterizing BMI categories and abdominal obesity the new variable showed a progressive increase in the odds of hypertension. Both BMI and WC should be included in models assessing hypertension risks.

Associations between trunk, leg and total body adiposity with arterial stiffness

BACKGROUND

Obesity and arterial stiffness are associated, but fat distribution patterns may be more strongly related to arterial stiffness than general obesity because of the possible increased inflammation associated with increased abdominal adiposity. The aims of this study were to examine whether fat patterning is associated with arterial stiffness, and determine whether these associations are mediated by low-grade inflammation.

METHODS

Adult participants from the Fels Longitudinal Study (228 males and 254 females) were assessed for brachial-ankle pulse wave velocity (BaPWV) to determine arterial stiffness. Dual energy X-ray absorptiometry was used to estimate fat percentage of the trunk and legs (e.g., TRUNKFAT% and LEGFAT%). High-sensitivity C-reactive protein (hs-CRP) levels were assayed as a general marker of inflammation. General linear regression analyses were used.

RESULTS

BaPWV was positively associated with TRUNKFAT% (r = 0.44 in men and r = 0.38 in women), whereas it was inversely related to LEGFAT% (r = -0.40 in men and r = -0.39 in women). In multiple regression analyses, each SD increase in TRUNKFAT% was associated with an ~1.03 m/s increase in BaPWV in both men and women. Each SD increase in LEGFAT% was related to a similar magnitude of decrease (1.03 m/s) in BaPWV in both sexes. The relationships of TRUNKFAT% and LEGFAT% with BaPWV were attenuated slightly when including hs-CRP in the models, but remained significant.

CONCLUSIONS

We found that trunk and leg fat are related to BaPWV in opposite directions when total body adiposity was accounted for. However, the associations between regional fat patterning and arterial stiffness did not appear to be mediated by low-grade inflammation.

Determinants of aortic stiffness: 16-year follow-up of the Whitehall II study

Background

Aortic stiffness is a strong predictor of cardiovascular disease endpoints. Cross-sectional studies have shown associations of various cardiovascular risk factors with aortic pulse wave velocity, a measure of aortic stiffness, but the long-term impact of these factors on aortic stiffness is unknown.

Methods

In 3,769 men and women from the Whitehall II cohort, a wide range of traditional and novel cardiovascular risk factors were determined at baseline (1991–1993) and aortic pulse wave velocity was measured at follow-up (2007–2009). The prospective associations between each baseline risk factor and aortic pulse wave velocity at follow-up were assessed through sex stratified linear regression analysis adjusted for relevant confounders. Missing data on baseline determinants were imputed using the Multivariate Imputation by Chained Equations.

Results

Among men, the strongest predictors were waist circumference, waist-hip ratio, heart rate and interleukin 1 receptor antagonist, and among women, adiponectin, triglycerides, pulse pressure and waist-hip ratio. The impact of 10 centimeter increase in waist circumference on aortic pulse wave velocity was twice as large for men compared with women (men: 0.40 m/s (95%-CI: 0.24;0.56); women: 0.17 m/s (95%-CI: −0.01;0.35)), whereas the opposite was true for the impact of a two-fold increase in adiponectin (men: −0.30 m/s (95%-CI: −0.51;−0.10); women: 0.61 m/s (95%-CI: −0.86;−0.35)).

Conclusion

In this large prospective study, central obesity was a strong predictor of aortic stiffness. Additionally, heart rate in men and adiponectin in women predicted aortic pulse wave velocity suggesting that strategies to prevent aortic stiffening should be focused differently by sex.

Evaluation of serum adipokines in peripheral arterial occlusive disease

Aim. Out study aimed to assess the serum levels of adipokines in patients with peripheral arterial occlusive disease (PAOD) caused by atherosclerosis. Methods. Serum samples were obtained from 221 patients. One hundred and forty patients, (26 females and 114 males) met the inclusion criteria and were assigned into the case group. Eighty one patients (17 females and 64 males), were included in the control group. Circulating plasma levels of adiponectin, leptin, resistin, and TNF-α were measured using the enzyme-linked immunosorbent assay (ELISA) method. Results. Significant lower levels of adiponectin were present (P = 0.0061) in PAOD patients (2380.23 ± 1634.42 pg/mL) compared to the control group (3065.06 ± 1901.2 pg/mL). The mean value of leptin (2844.42 ± 3301.08 pg/mL) and resistin (2047.81±3301.08 pg/mL) patients included in the PAOD group was higher, as compared to the control group. Statistically significant difference was found between the two groups for leptin (P = 0.0332) and for resistin (P = 0.0352). No statistically significant difference for TNF-α was found between the two groups (P > 0.05). Conclusion. The markers of inflammation secreted by the adipose tissue (adiponectin, leptin, resistin) showed significant differences in patients from the case group (with PAOD) compared to the control group.

Insulin resistance and arterial stiffness in healthy adolescents and young adults

AIMS/HYPOTHESIS

Increased arterial stiffness is a risk factor for adverse cardiovascular events in adults with obesity-related insulin resistance (IR) or type 2 diabetes mellitus. Adolescents with type 2 diabetes have stiffer vessels. Whether stiffness is increased in obesity/IR in youth is not known. We sought to determine if IR was a determinant of arterial stiffness in youth, independent of obesity and cardiovascular risk factors.

METHODS

We measured cardiovascular risk factors, IR, adipocytokines and arterial stiffness (brachial artery distensibility [BrachD], pulse wave velocity [PWV]) and wave reflection (augmentation index [AIx]) in 343 adolescents and young adults without type 2 diabetes (15-28 years old, 47% male, 48% non-white). Individuals <85th percentile of BMI were classified as lean (n = 232). Obese individuals were grouped by HOMA index as not insulin resistant (n = 46) or insulin resistant (n = 65) by the 90th percentile for HOMA for lean. Mean differences were evaluated by ANOVA. Multivariate models evaluated whether HOMA was an independent determinant of arterial stiffness.

RESULTS

Risk factors deteriorated from lean to obese to obese/insulin resistant (all p ≤ 0.017). Higher AIx, lower BrachD and higher PWV indicated increased arterial stiffness in obese and obese/insulin-resistant participants. HOMA was not an independent determinant. Age, sex, BMI and BP were the most consistent determinants, with HDL-cholesterol playing a role for BrachD and leptin for PWV (AIx R²= 0.34; BrachD R² = 0.37; PWV R² = 0.40; all p ≤ 0.02).

CONCLUSIONS/INTERPRETATION

Although IR is associated with increased arterial stiffness, traditional cardiovascular risk factors, especially obesity and BP, are the major determinants of arterial stiffness in healthy young people.

Adipokines and cardiovascular risk in Cushing's syndrome

Cushing's syndrome (CS) is associated with increased cardiovascular morbidity and mortality. Recent evidence also suggests that increased cardiovascular risk may persist even after long-term remission of CS. Increased central obesity, a typical feature of CS, is associated with altered production of adipokines, which contributes to the pathogenesis of several metabolic and cardiovascular complications observed in this condition. In vitro and in vivo studies have shown a relationship between cortisol and adipokines in several experimental settings. In patients with either active or 'cured' CS, an increase in leptin and resistin levels as well as the release of pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-6, may be associated with increased cardiovascular risk. For other adipokines, including adiponectin, results are inconclusive. Studies are needed to further elucidate the interactions between clinical and subclinical increases in cortisol production and altered adipokine release in CS.

Highly hydroxylated fullerene localizes at the cytoskeleton and inhibits oxidative stress in adipocytes and a subcutaneous adipose-tissue equivalent

Adipose tissue is a crucial site for pathologic changes in obesity/metabolic syndrome-related diseases. Interaction between adipogenesis and reactive oxygen species (ROS) in adipose tissue involving chronic low-grade inflammation is postulated to be causal in the development of insulin resistance and other metabolic consequences. We used different culture systems to investigate the relationship between ROS and adipogenesis at three levels: within adipocytes, during adipocyte-monocyte interactions, and in a subcutaneous adipose tissue model. The effects of highly hydroxylated fullerene (HHF; C(60)(OH)(36)) on adipogenesis-accompanying oxidative stress and inflammatory changes were examined using these three systems. We demonstrated that H(2)O(2) stimulates lipid accumulation in 3T3-L1 preadipocytes, and lipid uptake causes ROS generation in OP9 preadipocytes, both of which were then markedly suppressed with HHF treatment. HHF significantly inhibited the adipogenic stimulant insulin-rich serum replacement (SR)-induced triacylglycerol accumulation, ROS production, and macrophage activation in cultured OP9 cells and an OP9-U937 monocyte-like cell coculture system. H(2)O(2)-induced intracellular ROS production in OP9 adipocytes was also notably inhibited by HHF. We developed a three-dimensional subcutaneous adipose-tissue equivalent (SATE) consisting of air-exposed cultures of HaCaT keratinocytes on an OP9 adipocyte-populated collagen gel in a culture insert. With SR stimulation and under suitable conditions, fat accumulation, ROS generation, and macrophage infiltration were observed in the SATE and significantly inhibited by HHF. By western blotting, we demonstrated that HHF localized at the cytoskeleton, which controls the transport of lipids. In conclusion, HHF is able to inhibit oxidative stress in adipocytes and adipogenesis-related macrophage activation in adipose tissues through its antioxidation.

Increases in central fat mass and decreases in peripheral fat mass are associated with accelerated arterial stiffening in healthy adults: the Amsterdam Growth and Health Longitudinal Study

BACKGROUND

Central fatness is associated with higher arterial stiffness, a mechanism that may explain adiposity-related increases in cardiovascular disease risk. In contrast, peripheral fat and lean masses may counteract such adverse effects, but evidence of this contention, as derived from longitudinal studies at the general population level, is lacking.

OBJECTIVE

The objective was to investigate the associations between changes in central (ie, trunk) fat mass, peripheral (ie, limbs) fat mass, and lean masses with changes in arterial stiffness.

DESIGN

A longitudinal study in 277 (145 women) healthy adults was conducted. Body composition (dual-energy X-ray absorptiometry) and arterial stiffness estimates (ultrasound imaging) were measured repeatedly at the ages of 36 and 42 y.

RESULTS

Changes (per 10 kg) in trunk fat mass were positively associated and changes in peripheral fat mass were inversely associated with carotid Young's elastic modulus (in 10(3) ⋅ kPa) [β = 0.14 (95% CI: 0.02, 0.25) and -0.16 (-0.30, -0.01), respectively] and carotid-femoral pulse wave velocity (in m/s) [β = 1.54 (0.02, 3.07) and -1.46 (-3.48, 0.56), respectively]. Individuals in whom trunk fat increased and peripheral fat decreased over the 6-y follow-up (33% of the study population) had the steepest increases in these stiffness estimates. Notably, these changes were accompanied by minor increases in body weight, which remained within the limits of the normal range throughout.

CONCLUSIONS

Increases in trunk mass and decreases in peripheral fat mass are associated with accelerated arterial stiffening. These findings emphasize the importance of assessing regional changes in body composition, because it may enable identification of individuals with an unrecognized increased cardiovascular disease risk.