Cardiovascular metabolic syndrome - an interplay of, obesity, inflammation, diabetes and coronary heart disease

Impacto hormonal e inflamatório de diferentes composições dietéticas: ênfase em padrões alimentares e fatores dietéticos específicos

A adoção de um padrão alimentar saudável, caracterizado pelo consumo de frutas, hortaliças, carnes magras, lácteos desnatados, frutos secos e moderada ingestão de óleos vegetais e álcool, é um fator determinante para um menor risco de doenças crônicas como a obesidade, a síndrome metabólica e as doenças cardiovasculares. Esse efeito benéfico pode ser explicado, pelo menos em parte, por seu papel modulador sobre biomarcadores da sensibilidade insulínica, da aterogênese, bem como os de inflamação e de função endotelial. Por outra parte, a ingestão de componentes específicos da dieta como os ácidos graxos insaturados (oleico e alfa-linolênico) e os micronutrientes com propriedades antioxidantes (vitaminas A, E e C; selênio e zinco) vêm sendo discutida, em razão de sua potencial ação protetora perante a ocorrência das doenças crônicas e possíveis benefícios na regulação hormonal, metabólica e inflamatória que esses fatores dietéticos podem proporcionar dentro de um tratamento nutricional para a obesidade e a síndrome metabólica.

A randomized controlled trial of the effects of flaxseed lignan complex on metabolic syndrome composite score and bone mineral in older adults

A randomized double-blind placebo controlled study design was used to assess the effects of flaxseed lignan complex supplementation during exercise training on a metabolic syndrome composite score and osteoporosis risk in older adults. A total of 100 subjects (>or=50 years) were randomized to receive flaxseed lignan (543 mg.day-1 in a 4050 mg complex) or placebo while completing a 6 month walking program (30-60 min.day-1, 5-6 days.week-1). Fasting serum glucose, triacylglycerol (TAG), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, total cholesterol, interleukin-6, and tumor necrosis factor-alpha were measured every 2 months, while body composition, bone mineral density, and resting blood pressure were assessed at baseline and at 6 months. A composite Z score of 6 risk factors for metabolic syndrome (fasting glucose, HDL cholesterol, TAG, abdominal adiposity, blood pressure, and inflammatory cytokines) was calculated at baseline and at 6 months. Men taking placebo increased metabolic syndrome composite Z score (p < 0.05), but there were no changes in the other groups. A significant group x sex x time interaction was noted for TAG (p = 0.017) and diastolic blood pressure (p = 0.046), with men taking flaxseed lignan decreasing diastolic blood pressure relative to men taking placebo, and men taking placebo increasing TAG relative to men taking flax lignan. There were no differences between groups for change in bone measures, body composition, lipoproteins, or cytokines. Males taking the flaxseed lignan complex reduced metabolic syndrome score relative to men taking placebo, but a similar trend was not seen in females. Flaxseed lignan had no effect on bone mineral density or content, body composition, lipoproteins, glucose, or inflammation.

Effect of exercise training on cardiometabolic risk markers among sedentary, but metabolically healthy overweight or obese post-menopausal women with elevated blood pressure

OBJECTIVE

To investigate the effect of exercise training on markers of the lipoprotein-lipid profile and inflammatory markers in post-menopausal overweight/obese women with a moderately elevated systolic blood pressure.

METHODS

A total of 267 women [mean body mass index (BMI)=32.0+/-5.7kg/m(2) and mean age=57.3+/-6.6 years] underwent a 6-month exercise intervention program. Exercise training was performed 3-4 times per week at a targeted heart rate corresponding to 50% of the maximal oxygen consumption.

RESULTS

Compared to baseline values, mean change in relative VO(2) max (the primary endpoint) was of 1.18+/-2.25mL/minkg (p<0.0001), mean weight loss was of 1.4+/-3.3kg (p<0.0001), mean reduction in waist circumference was of 2.4+/-6.9cm (p<0.0001) and systolic blood pressure did not change significantly (-1.2+/-13.0mmHg, NS). No changes were observed in markers of the lipoprotein-lipid profile. No changes were observed for plasma levels of C-reactive protein, interleukin-6, tumor-necrosis factor-alpha and adiponectin. Changes in VO(2) max were negatively associated with changes in body weight (r=-0.26, p<0.0001) and waist circumference (r=-0.16, p=0.01), but not with changes in cardiometabolic risk markers.

CONCLUSION

Although exercise training significantly increased cardiorespiratory fitness in these sedentary, but metabolically healthy obese/overweight women with a moderately elevated systolic blood pressure, no significant improvements were observed in their cardiometabolic risk profile.

Depressive symptoms and increased visceral fat in middle-aged women

OBJECTIVE

To examine whether depressive symptoms are differentially associated with visceral adipose tissue (VAT), which is more metabolically active and confers greater cardiovascular risk than subcutaneous fat (SAT). Prior research has shown an association between depression and central adiposity. Mechanisms underlying the association between depression and increased cardiovascular risk remain poorly understood. Central adiposity is one potential pathway.

METHODS

We investigated the cross-sectional association between depressive symptoms, assessed by the Center for Epidemiological Studies Depression Scale (CES-D), and VAT and SAT, assessed by computed tomography, in a sample of 409 middle-aged women (44.7% African-Americans, 55.3% Whites; mean age = 50.4 years) participating in the Chicago site of the Study of Women's Health Across the Nation (SWAN).

RESULTS

With adjustments for age, race, total percent fat, and sex hormone binding globulin (SHBG), each 1-point higher score on the CES-D was associated with 1.03-cm(2) greater VAT (p < .001). Women with a CES-D score of >or=16, indicative of clinically relevant depressive symptomatology, had 24.5% more VAT than women with lower CES-D scores (p < .001). Further adjustment for Framingham Risk Score and physical activity did not alter the findings, and associations did not vary by race. Associations were strongest in obese and overweight women. Depressive symptoms were unrelated to SAT.

CONCLUSIONS

Increased visceral fat may be one pathway by which depression contributes to excess risk for cardiovascular disease and diabetes. Further research is needed to examine whether depressive symptoms influence accumulation of VAT over time.

Inflammation as a therapeutic target in heart failure? A scientific statement from the Translational Research Committee of the Heart Failure Association of the European Society of Cardiology

The increasing prevalence of heart failure poses enormous challenges for health care systems worldwide. Despite effective medical interventions that target neurohumoral activation, mortality and morbidity remain substantial. Evidence for inflammatory activation as an important pathway in disease progression in chronic heart failure has emerged in the last two decades. However, clinical trials of 'anti-inflammatory' therapies (such as anti-tumor necrosis factor-alpha approaches) have to date failed to show benefit in heart failure patients. The Heart Failure Association of the European Society of Cardiology recently organized an expert workshop to address the issue of inflammation in heart failure from a basic science, translational and clinical perspective, and to assess whether specific inflammatory pathways may yet serve as novel therapeutic targets for this condition. This consensus document represents the outcome of the workshop and defines key research questions that still need to be addressed as well as considering the requirements for future clinical trials in this area.

The prevalence of metabolic syndrome in an employed population and the impact on health and productivity

OBJECTIVE

To investigate the prevalence of metabolic syndrome in an employed population and its association with health risks, health perception, illness days, work limitation (presenteeism), and short-term disability (STD).

METHODS

Five thousand five hundred twelve employees of a financial services company responded to an on-site health risk appraisal which included measured waist circumference and biometric results. The metabolic syndrome criteria were based on the 2005 AHA/NHLBI scientific statement on the diagnosis and management of metabolic syndrome. Perceived health, illness days, and presenteeism were self-reported; STD days were obtained from claims data.

RESULTS

In this employee population (61% women, average age 41 years), 22.6% met the criteria for metabolic syndrome and were more likely to report more health risks, poorer health perception, and more absent days due to illness. There was no clear association with presenteeism or STD incidence. However, as the number of metabolic risk factors increased, there was an increase in STD incidence, decrease in health perception, and increase in illness days. No association was found with number of metabolic risk factors and presenteeism.

CONCLUSIONS

Metabolic syndrome was associated with poor perceived health, increased illness days, and an increased trend of STD incidence. Worksite health promotion programs could be useful in helping employees and employers to identify metabolic syndrome risks and take steps to reduce risk and potential productivity losses.

Effect of diet on the low-grade and chronic inflammation associated with obesity and metabolic syndrome

Adipose tissue is an active endocrine and paracrine organ that releases a large number of cytokines and biomarkers, which are involved in the development of chronic diseases. These effects have been attributed to direct or indirect mechanisms acting on insulin resistance, inflammation and endothelial dysfunction. In addition, the expression and secretion of these biomarkers in various tissues can be influenced by dietary patterns, with an effect on inflammatory status. In this context, following an energy-balanced diet, moderate in carbohydrates, high in oleic and omega-3 fatty acids, and low in saturated and trans fatty acids, with high intake of fruits and legumes and moderate alcohol consumption, appears to have beneficial effects on the inflammatory state associated with obesity and the manifestations of metabolic syndrome. However, the long-term impact of habitual intake and the mechanisms involved in distinct physiological and pathological conditions remain unclear.

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.

Increased activity of interleukin-23/interleukin-17 proinflammatory axis in obese women

OBJECTIVE

To compare the concentrations of cytokines belonging to Th17 axis (interleukin (IL)-17 and IL-23) and Th1 axis (IL-12 and interferon (IFN)-gamma) in obese and lean women, and to investigate their relationships with the proinflammatory adipokine leptin, proinflammatory cytokine macrophage migration inhibitory factor (MIF) and anthropometric and metabolic parameters of obesity.

DESIGN

Cross-sectional study.

SUBJECTS

Twenty-six obese women (age 20-52 years, body mass index (BMI): 30-48 kg/m(2)) and 20 healthy lean women (age 23-46 years, BMI: 18-25 kg/m(2)).

MEASUREMENTS

Plasma levels of cytokines and leptin, BMI, waist circumference (WC) and insulin resistance index HOMA (homeostatic model assessment).

RESULTS

Blood concentrations of IL-17, IL-23, MIF and leptin, but not IL-12 or IFN-gamma, were higher in obese compared with lean women (P=0.002, 0.046, 0.006 and 0.002, respectively). There was a positive correlation between IL-17 and IL-23 (r(s)=0.530), which was at the border of statistical significance (P=0.065). Neither IL-17 nor IL-23 correlated with leptin or MIF, and there was no association between IL-17 and IL-23 levels with BMI, WC or HOMA index.

CONCLUSION

Interleukin-23/IL-17 axis is stimulated in obese women independently of the increase in abdominal fat, insulin resistance, leptin and MIF levels.

Captopril normalizes insulin signaling and insulin-regulated substrate metabolism in obese (ob/ob) mouse hearts

The goal of this study was to determine whether inhibiting the renin-angiotensin system would restore insulin signaling and normalize substrate use in hearts from obese ob/ob mice. Mice were treated for 4 wk with Captopril (4 mg/kg x d). Circulating levels of free fatty acids, triglycerides, and insulin were measured and glucose tolerance tests performed. Rates of palmitate oxidation and glycolysis, oxygen consumption, and cardiac power were determined in isolated working hearts in the presence and absence of insulin, along with levels of phosphorylation of Akt and AMP-activated protein kinase (AMPK). Captopril treatment did not correct the hyperinsulinemia or impaired glucose tolerance in ob/ob mice. Rates of fatty acid oxidation were increased and glycolysis decreased in ob/ob hearts, and insulin did not modulate substrate use in hearts of ob/ob mice and did not increase Akt phosphorylation. Captopril restored the ability of insulin to regulate fatty acid oxidation and glycolysis in hearts of ob/ob mice, possibly by increasing Akt phosphorylation. Moreover, AMPK phosphorylation, which was increased in hearts of ob/ob mice, was normalized by Captopril treatment, suggesting that in addition to restoring insulin sensitivity, Captopril treatment improved myocardial energetics. Thus, angiotensin-converting enzyme inhibitors restore the responsiveness of ob/ob mouse hearts to insulin and normalizes AMPK activity independently of effects on systemic metabolic homeostasis.

Blockade of alpha4 integrin signaling ameliorates the metabolic consequences of high-fat diet-induced obesity

OBJECTIVE

Many prevalent diseases of advanced societies, such as obesity-induced type 2 diabetes, are linked to indolent mononuclear cell-dependent inflammation. We previously proposed that blockade of alpha4 integrin signaling can inhibit inflammation while limiting mechanism-based toxicities of loss of alpha4 function. Thus, we hypothesized that mice bearing an alpha4(Y991A) mutation, which blocks signaling, would be protected from development of high-fat diet-induced insulin resistance.

RESEARCH DESIGN AND METHODS

Six- to eight-week-old wild-type and alpha4(Y991A) C57Bl/6 male mice were placed on either a high-fat diet that derived 60% calories from lipids or a chow diet. Metabolic testing was performed after 16-22 weeks of diet.

RESULTS

Alpha4(Y991A) mice were protected from development of high-fat diet-induced insulin resistance. This protection was conferred on wild-type mice by alpha4(Y991A) bone marrow transplantation. In the reverse experiment, wild-type bone marrow renders high-fat diet-fed alpha4(Y991A) acceptor animals insulin resistant. Furthermore, fat-fed alpha4(Y991A) mice showed a dramatic reduction of monocyte/macrophages in adipose tissue. This reduction was due to reduced monocyte/macrophage migration rather than reduced monocyte chemoattractant protein-1 production.

CONCLUSIONS

Alpha4 integrins contribute to the development of HFD-induced insulin resistance by mediating the trafficking of monocytes into adipose tissue; hence, blockade of alpha4 integrin signaling can prevent the development of obesity-induced insulin resistance.

High-fat, energy-dense, fast-food-style breakfast results in an increase in oxidative stress in metabolic syndrome

The metabolic syndrome (MetS) is associated with an increased incidence of diabetes and coronary heart disease. Postprandial lipemia is a prominent feature of dyslipidemia in both type 2 diabetes mellitus and MetS and is also associated with coronary heart disease. Oxidative stress and inflammation are pivotal in all stages of atherosclerosis; however, there is a paucity of data on postprandial oxidative stress and inflammation in subjects with MetS. Thus, the primary aim of this study was to compare the postprandial effects of an energy-dense, high-fat, fast-food-style (FFS) meal with an American Heart Association (AHA)-recommended heart-healthy meal on biomarkers of oxidative stress and inflammation in subjects with MetS. A total of 11 subjects with MetS completed the study. Glucose levels were significantly increased 2 hours after both FFS and AHA diets (P < .0001), and high-density lipoprotein cholesterol levels significantly decreased in FFS diet but not in the AHA diet (P for interaction < .05). Total triglyceride levels significantly increased postprandially only in the FFS meal but not in the AHA meal (P for interaction = .03). Plasma thiobarbituric acid reactive substances and malondialdehyde + hydroxynonenal increased significantly with time in both dietary groups, and the postprandial increase was greater in the FFS diet compared to the AHA diet (P < .0005). Serum high-sensitivity C-reactive protein, interleukin 6, and tumor necrosis factor levels did not change with time or dietary treatment. The postprandial increase in interleukin 1b was significantly higher with the FFS meal, thus resulting in significant differences between both treatments (P for interaction = .03). Thus, in subjects with MetS, consumption of an energy-dense, fatty meal (FFS breakfast) results in increased postprandial oxidative stress compared to a heart-healthy meal (AHA).

Added impact of obesity and insulin resistance in nocturnal blood pressure elevation in children and adolescents

The aim of the present study was to analyze the relationship between insulin resistance and the ambulatory blood pressure components in obese children and adolescents. Eighty-seven overweight and obese white children and adolescents of both sexes, of European origin from 6 to 18 years of age (mean age: 10.9+/-2.7 years), were selected. Obesity was defined on the basis of a threshold body mass index z score >2 (Cole's least mean square method) and overweight with a body mass index from the 85th to 97th percentile. A validated oscillometric method was used to measure ambulatory BP (Spacelabs 90207) during 24 hours. Fasting glucose and insulin were measured, and the homeostasis model assessment index was calculated. Subjects were grouped into tertiles of homeostasis model assessment index. No significant differences in terms of age, sex, and body mass index z score distribution were observed among groups. When adjusted by age, sex, and height, nocturnal systolic blood pressure and heart rate were significantly higher in subjects in the highest homeostasis model assessment index tertile (>4.7) as compared with those of the other groups, whereas no differences were observed for awake systolic blood pressure or heart rate. Whereas body mass index z score was more closely related with blood pressure and heart rate values, waist circumference was strongly related with insulin resistance. Moreover, both waist circumference and insulin resistance were mainly associated with higher nocturnal but not with awake blood pressure. The early increment of nocturnal blood pressure and heart rate associated with hyperinsulinemia may be a harbinger of hypertension-related insulin resistance and may contribute to heightened cardiovascular risk associated with this condition.

The proinflammatory phenotype of PECAM-1-deficient mice results in atherogenic diet-induced steatohepatitis

The severity of nonalcoholic steatohepatitis (NASH) is determined by environmental and genetic factors, the latter of which are incompletely characterized. Platelet endothelial cell adhesion molecule-1 (PECAM-1) is a 130-kDa transmembrane glycoprotein expressed on blood and vascular cells. In the present study, we provide data for the novel finding that genetic deficiency of PECAM-1 potentiates the development and progression of NASH. We found that the rate of development and severity of diet-induced NASH are markedly enhanced in PECAM-1-deficient [knockout (KO)] mice relative to wild-type (WT) mice, as measured by histological and biochemical evaluation. Livers from KO mice exhibited typical histological features of NASH, including macrovesicular fat accumulation, hepatocyte injury with infiltration of inflammatory cells, fibrosis, and heightened oxidative stress. Alanine aminotransferase, a marker for liver injury, was also significantly higher in KO compared with WT mice. Consistent with a role for PECAM-1 as a suppressor of proinflammatory cytokines, plasma levels of inflammatory cytokines, including TNF-alpha and monocyte chemoattractant protein-1 (MCP-1), were also significantly higher in KO compared with WT mice. These findings are the first to show that the PECAM-1-deficient mouse develops progressive nonalcoholic fatty liver disease (NAFLD), supporting a role for PECAM-1 as a negative regulator of NAFLD progression. Future examination of recently identified PECAM-1 allelic isoforms in humans as potential risk factors for developing NASH may be warranted.

Clinical implications of the metabolic syndrome

The prevalence of the metabolic syndrome among developed countries is rising, and this is largely driven by increasing obesity rates. Central obesity plays a key role in the pathogenesis of the metabolic syndrome: it promotes inflammation, hypertension and dyslipidaemia, and leads to the development of type 2 diabetes mellitus and atherosclerosis. Clinical management should be focused on multifactorial intervention to address all the associated cardiovascular risk factors. The atherogenic mixed dyslipidaemic profile associated with the metabolic syndrome is an important target for intervention to reduce the risk of type 2 diabetes and premature cardiovascular disease.

Cardiac proinflammatory pathways are altered with different dietary n-6 linoleic to n-3 alpha-linolenic acid ratios in normal, fat-fed pigs

Although dietary fat has been associated with inflammation and cardiovascular diseases (CVD), most studies have focused on individuals with preexisting diseases. However, the role of dietary fatty acids on inflammatory pathways before the onset of any abnormality may be more relevant for identifying initiating factors and interventions for CVD prevention. We fed young male pigs one of three diets differing in n-6 and n-3 polyunsaturated fatty acids (PUFA) linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (ALA, 18:3n-3) for 30 days. Cardiac membrane phospholipid fatty acids, phospholipase A(2) (PLA(2)) isoform activities, and cyclooxygenase (COX)-1 and -2 and 5-lipoxygenase (5-LO) expression were measured. The low PUFA diet (% energy, 1.2% LA+0.06% ALA) increased arachidonic acid (AA) and decreased eicosapentaenoic acid (EPA) in heart membranes and increased Ca(2+)-independent iPLA(2) activity, COX-2 expression, and activation of 5-LO. Increasing dietary ALA while keeping LA constant (1.4% LA+1.2% ALA) decreased the heart membrane AA, increased EPA, and prevented proinflammatory enzyme activation. However, regardless of high ALA, high dietary LA (11.6% LA and 1.2% ALA) decreased EPA and led to a high heart membrane AA, and Ca(2+)-dependent cPLA(2) with a marked increase in nitrosative stress. Our results suggest that the potential cardiovascular benefit of ALA is achieved only when dietary LA is reduced concomitantly rather than fed with high LA diet. The increased nitrosative stress in the unstressed heart with high dietary LA suggests that biomarkers of nitrosative stress may offer a useful early marker of the effects of dietary fat on oxidative tissue stress.

An evaluation of 3,4-methylenedioxy phenyl replacements in the aminopiperidine chromone class of MCHr1 antagonists

The optimization of potent MCHr1 antagonist 1 with respect to improving its in vitro profile by replacement of the 3,4-methylenedioxy phenyl (piperonyl) moiety led to the discovery of 19, a compound that showed excellent MCHr1 binding and functional potencies in addition to possessing superior hERG separation, CYP3A4 profile, and receptor cross-reactivity profiles.