Epicardial fat, cardiac dimensions, and low-grade inflammation in young adult monozygotic twins discordant for obesity

Epicardial fat with its close proximity to coronary arteries has been suggested to be a significant predictor of cardiovascular disease. We studied the relations among acquired obesity, low-grade inflammation, and genetic factors in the accumulation of epicardial fat. A rare sample (n = 15) of healthy monozygotic (MZ) twin pairs discordant for obesity (intrapair difference in body mass index ≥3 kg/m(2)) and 9 concordant MZ pairs 23 to 33 years old were examined for cardiac structure, function, epicardial fat thickness (echocardiography), abdominal subcutaneous tissue, and visceral adipose tissue (VAT), liver fat (magnetic resonance imaging/spectroscopy), and serum high-sensitivity C-reactive protein. In the entire sample, MZ cotwins were remarkably similar in most echocardiographic measurements including epicardial fat (intraclass correlation 0.63, p = 0.0004). However, in the discordant pairs, the obese cotwins (16.5 kg, 23% heavier) had 26% more epicardial fat (p = 0.0029) than nonobese cotwins. They also had significantly larger atrial and left ventricular dimensions. Epicardial fat correlated with VAT (r = 0.49, p = 0.02) in individual twins and when using intrapair differences of measurements within pairs (r = 0.39, p = 0.06). In multiple regression analyses including abdominal subcutaneous tissue, VAT, and liver fat, high-sensitivity C-reactive protein was the only factor that remained significantly associated with epicardial fat in individual twins and within pairs. In conclusion, subjects who share the same genes seem to have similar cardiac dimensions. However, acquired obesity increases epicardial fat independent of genetic factors. The close relation between epicardial fat and low-grade inflammation is likely to contribute to the development of cardiovascular disease in obesity.     

La grasa epicárdica se relaciona con la visceral,el síndrome metabólico y la resistencia a la insulina en mujeres menopáusicas

Introduction and objectives

Epicardial adipose tissue has been associated with several obesity-related parameters and with insulin resistance. Echocardiographic assessment of this tissue is an easy and reliable marker of cardiometabolic risk. However, there are insufficient studies on the relationship between epicardial fat and insulin resistance during the postmenopausal period, when cardiovascular risk increases in women. The objective of this study was to examine the association between epicardial adipose tissue and visceral adipose tissue, waist circumference, body mass index, and insulin resistance in postmenopausal women.

Methods

A cross sectional study was conducted in 34 postmenopausal women with and without metabolic syndrome. All participants underwent a transthoracic echocardiogram and body composition analysis.

Results

A positive correlation was observed between epicardial fat and visceral adipose tissue, body mass index, and waist circumference. The values of these correlations of epicardial fat thickness overlying the aorta-right ventricle were r = 0.505 (P < .003), r = 0.545 (P < .001), and r = 0.515 (P < .003), respectively. Epicardial adipose tissue was higher in postmenopausal women with metabolic syndrome than in those without this syndrome (mean [standard deviation], 544.2 [122.9] vs 363.6 [162.3] mm ²; P = .03).

Conclusions

Epicardial fat thickness measured by echocardiography was associated with visceral adipose tissue and other obesity parameters. Epicardial adipose tissue was higher in postmenopausal women with metabolic syndrome. Therefore, echocardiographic assessment of epicardial fat may be a simple and reliable marker of cardiovascular risk in postmenopausal women.Full English text available from:www.revespcardiol.org/en     

Relation of subepicardial adipose tissue to carotid intima-media thickness in patients with human immunodeficiency virus

Patients infected with human immunodeficiency virus (HIV) are at increased risk for subclinical atherosclerosis. Whether increased cardiac adiposity may be related to HIV subclinical atherosclerosis is still unexplored. The objective of this study was to evaluate whether echocardiographically determined subepicardial adipose tissue, an index of cardiac adiposity, is related to carotid intima-media thickness (IMT), an index of subclinical atherosclerosis, in HIV-infected patients receiving highly active antiretroviral therapy. Echocardiographic epicardial fat thickness and ultrasonographic IMT were measured in 103 consecutive HIV-infected Caucasian subjects receiving highly active antiretroviral therapy. Echocardiographic subepicardial adipose tissue showed an excellent correlation with IMT (r = 0.92, p <0.01). Multiple regression analysis showed that IMT was best predicted by epicardial fat thickness (r(2) = 0.81, p <0.01). In conclusion, this study suggests, for the first time, that epicardial adipose tissue, an index of cardiac adiposity, may be significantly related to subclinical atherosclerosis in HIV-infected patients.     

Are dual-energy X-ray absorptiometry regional estimates associated with visceral adipose tissue mass?

OBJECTIVE: Recent studies support the possibility of estimating abdominal fat using a region of interest (ROI) selected by conventional whole body dual-energy X-ray absorptiometry (DXA). This is an important observation as DXA ROI estimates have some advantages over waist circumference or computed tomography/magnetic resonance imaging (MRI) as a means of assessing visceral adipose tissue (VAT) and adipose tissue distribution. The aim of this study was to evaluate the usefulness of DXA abdominal ROI estimates in assessing VAT among non-obese men. DESIGN: Observational, cross-sectional study comparing correlations between MRI-measured total VAT and surrogate measures including DXA ROIs. A stepwise multiple regression model was applied to derive a predictive equation with total VAT mass. SUBJECTS: Ninety non-obese healthy men between the ages of 18 and 44 y with BMI<30 kg/m(2). MEASUREMENTS: Abdominal adipose tissue and total VAT were measured by whole body MRI; VAT area by single-slice MRI at the L4-5 level; specific DXA ROIs for abdominal regional fat defined as ROI A (L2-4), B (L2-upper iliac), C (lower costal-upper iliac), and D (ROI C excluding spine); and simple anthropometric measures. RESULTS: Correlations between total VAT and ROIs A (r=0.85) and B (r=0.84) were not significantly different from that of VAT area at L4-5 (r=0.87), but significantly higher (P <0.01) than that of waist circumference (r=0.77). The highest correlations with total abdominal adipose tissue were for DXA ROIs and conventional DXA trunk fat (r=0.95-0.97). A stepwise multiple regression analysis revealed that 86% of the variance in total VAT was predicted by VAT area at L4-5, ROI A, and waist-hip ratio. CONCLUSIONS: DXA ROIs (L2-4, L2-upper iliac) were associated with total VAT as well as MRI-derived VAT area at L4-5 in non-obese men. DXA ROI fat distribution estimates may be useful in the early detection of men with abdominal/visceral obesity.     

Insulin sensitivity is correlated with subcutaneous but not visceral body fat in overweight and obese prepubertal children

AIM: Our aim was to explore the relationship between insulin sensitivity, body fat distribution, ectopic (liver and skeletal muscle) fat deposition, adipokines (leptin and adiponectin), and inflammation markers (highly sensitive C-reactive protein, IL-6, IL-10, and TNF-alpha) in prepubertal children. SUBJECTS AND METHODS: Thirty overweight and obese children (16 males and 14 females with body mass index z-score range of 1.1-3.2) were recruited. Body fat distribution and fat accumulation in liver and skeletal muscle were measured using magnetic resonance imaging. Insulin sensitivity was assessed by iv glucose tolerance test. RESULTS: Insulin sensitivity was associated with sc abdominal adipose tissue (SAT) (r = -0.52; P < 0.01) and liver fat content (r = -0.44; P < 0.02) but not with visceral abdominal adipose tissue (VAT) (r = -0.193; P value not significant) and fat accumulation in skeletal muscle (r = -0.210; P value not significant). Adipokines, but not inflammation markers, were significantly correlated to insulin sensitivity. VAT correlated with C-reactive protein (r = 0.55; P < 0.01) as well as adiponectin (r = -0.53; P <0.01). Multiple regression analysis showed that only SAT and liver fat content were independently correlated to insulin sensitivity (P < 0.01; 20 and 16% of explained variance, respectively). CONCLUSIONS: In overweight and moderately obese prepubertal children, insulin sensitivity was negatively correlated with SAT and liver fat content. Furthermore, contrary to adults, VAT and inflammation markers were not correlated with insulin sensitivity in children.     

Epicardial adipose tissue: anatomic, biomolecular and clinical relationships with the heart

A growing amount of evidence suggests that regional fat distribution plays an important part in the development of an unfavorable metabolic and cardiovascular risk profile. Epicardial fat is a metabolically active organ that generates various bioactive molecules, which might significantly affect cardiac function. This small, visceral fat depot is now recognized as a rich source of free fatty acids and a number of bioactive molecules, such as adiponectin, resistin and inflammatory cytokines, which could affect the coronary artery response. The observed increases in concentrations of inflammatory factors in patients who have undergone coronary artery bypass grafting remain to be confirmed in healthy individuals. Furthermore, epicardial adipose mass might reflect intra-abdominal visceral fat. Therefore, we propose that echocardiographic assessment of this tissue could serve as a reliable marker of visceral adiposity. Epicardial adipose tissue is also clinically related to left ventricular mass and other features of the metabolic syndrome, such as concentrations of LDL cholesterol, fasting insulin and adiponectin, and arterial blood pressure. Echocardiographic assessment of epicardial fat could be a simple and practical tool for cardiovascular risk stratification in clinical practice and research. In this paper, we briefly review the rapidly emerging evidence pointing to a specific role of epicardial adipose tissue both as a cardiac risk marker and as a potentially active player in the development of cardiac pathology.     

Distribution of abdominal adiposity and cardiovascular risk factors in yaquis indians from sonora, méxico

Background: Studies on adiposity in indigenous populations from Mexico are scarce and there are not previous reports that examine the topography of abdominal fat depot and cardiovascular risk factors. Therefore, we determined the distribution of abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT), and analyzed its relationship with cardiovascular risk factors, in Yaqui Indians. Methods: In a cross-sectional population based study, a total of 82 apparently healthy Yaqui Indians (age 44 +/- 14 years and BMI 27.9 +/- 4.2 kg/m(2)) were randomly enrolled from Vicam, Bacum, and Potam, traditional Yaqui communities from Sonora, in northwest Mexico. Anthropometric parameters, single-slice computed tomography scans at the L(2)-L(3) intervertebral space, fasting glucose, insulin, and lipid profile were assessed. Results: A total of 49 (59.7%) individuals were obese, showing a predominant area of abdominal SAT (319.5 +/- 118.2 cm(2)) over abdominal VAT (134.6 +/- 58.4 cm(2)). Both abdominal VAT (r = 0.54, P = .001; and r = 0.36, P = .01) and SAT (r = 0.15, P = .001; r = 0.47, P = .01) were positively correlated with age and BMI. Abdominal VAT was positively correlated with insulin (r = 0.69, P = .0001) and triglycerides levels (r = 0.42, P = .01). Conclusions: Among Yaquis Indians, obesity with predominant abdominal SAT is common and hyperinsulinemia is the most frequent cardiovascular risk factor. Abdominal VAT, but not abdominal SAT, was related to hyperinsulinemia and hypertriglyceridemia.     

Relationship between vaspin gene expression and abdominal fat distribution of Korean women

Visceral adipose tissue-derived serpin (vaspin) is a novel adipokine that is thought to have insulin-sensitizing effects. We investigated vaspin mRNA expression in abdominal adipose tissue and examined how gene expression related to abdominal fat distribution and metabolic parameters in Korean women. We measured anthropometric variables, metabolic parameters, serum vaspin concentration, and vaspin mRNA expression in abdominal adipose tissue obtained from women who underwent abdominal gynecological surgery and were aged 18-67 years (n = 85). Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) area were measured in 40 subjects using computed tomography (CT). Vaspin expression was analyzed by real-time quantitative RT-PCR according to abdominal fat distribution. Vaspin mRNA expression was greater in adipocytes than in stroma/vascular cells. In the total subjects, vaspin expression was significantly higher in SAT than in VAT. Vaspin expression in SAT in subcutaneous fat type (VSR ≤ 0.3) was significantly higher than in visceral fat type (VSR > 0.3), although vaspin expression in VAT was similar between subcutaneous and visceral fat type. There was a significant negative correlation between vaspin expression in SAT and VAT area (r = -0.55, p = 0.001). Serum vaspin concentration was significantly correlated with fasting insulin (r = 0.30, p = 0.02), HOMA-IR (r = 0.29, p = 0.02), and the ratio of vaspin expression in VAT to vaspin expression in SAT (r = 0.41, p = 0.04). Vaspin expression in abdominal adipose tissue was adipocyte-specific and vaspin expression in SAT decreased as VAT area increased.     

Sexual dimorphism in circulating leptin concentrations is not accounted for by differences in adipose tissue distribution

BACKGROUND: Circulating concentrations of leptin normalized to total adipose tissue mass are significantly greater in females than in males. Rates of leptin expression (per gram of adipose tissue) are significantly greater in subcutaneous (SAT) than visceral (VAT) adipose tissue and the relative amount of fat stored as SAT vs VAT is significantly greater in pre-menopausal females than in males. Gender-related differences in the relative amounts of SAT and VAT may account for the greater circulating leptin concentration relative to fat-mass in females than males. METHODS: We examined body composition and anatomic fat distribution by dual energy X-ray-absorptiometry (DEXA) and magnetic resonance imaging (MRI), and post-absorptive circulating concentrations of leptin and insulin in 58 subjects (26 females, 32 males). Stepwise multiple linear regression analyses, treating gender as a dichotomous variable, were performed to determine inter-relationships among leptin concentrations and insulin concentrations, VAT and SAT. RESULTS: Body composition by DEXA and MRI were highly correlated (r(2)=0.97, P<0.0001). There were significant gender effects on leptin/total fat mass (males, 0.17+/-0.01 ng/ml/kg; females, 0.49+/-0.05 ng/ml/kg; P<0.0001) and relative amounts of fat in SAT and VAT depots (ratio of SAT/VAT; males, 12.3+/-1.5; females, 32.9+/-3.2; P<0.0001). Circulating leptin concentration was significantly correlated with insulin concentration (P=0.001), SAT (P<0.0001) and gender (P=0.033). Circulating concentrations of insulin were significantly correlated with VAT, but not SAT, in males and with SAT, but not VAT, in females. CONCLUSIONS: The sexual dimorphism in the relationship between leptin and adipose tissue mass cannot be explained by differences in the relative amounts of VAT and SAT. Thus, the sexual dimorphism in plasma leptin concentration appears to reflect, at least in part, effects of circulating concentrations of gonadal steroids (especially androgens) and/or primary genetic differences that are independent of amounts of VAT or SAT.     

超重和肥胖成人心外膜脂肪组织和胰岛素抵抗的关系研究

目的研究超重和肥胖成人胰岛素敏感性、胰岛素抵抗及心外膜脂肪组织和胰岛素抵抗的关系。方法收集2005年3月至2005年12月在我院体检中心符合入选标准的资料210份,均具人体指标测量、空腹血生化检查和经超声测量心外膜脂肪组织厚度、腹壁脂肪厚度(SFT)等数据,根据中国肥胖工作组推荐的判定标准,分为超重肥胖组和体重正常组。采用稳态模式胰岛素抵抗指数(HOMA-IR)评价胰岛素抵抗。用SPSS 13.0软件进行统计分析。结果超重肥胖组SI显著低于体重正常组(P<0.01),FINS、HOMA-IR显著高于体重正常组(P<0.01),心外膜脂肪组织厚度明显厚于体重正常组(P<0.01);控制年龄、性别、腰围影响因素进行偏相关分析,显示心外膜脂肪组织厚度和FINS、HOMA-IR成正相关,相关系数分别为0.239、0.249,P<0.05;和SI成负相关,相关系数为0.249,P<0.05,SFT则与各个因素无相关性;逐步法多元线性回归分析显示,心外膜脂肪组织厚度和HOMA-IR呈正相关,标准化偏回归系数0.309,P<0.01,而SFT仅和BMI呈正相关。结论超重肥胖成人存在胰岛素敏感性降低、胰岛素抵抗,心外膜脂肪组织厚度和胰岛素抵抗成正相关,可能是新的心血管和代谢疾病的危险因素。     

Japanese men have larger areas of visceral adipose tissue than Caucasian men in the same levels of waist circumference in a population-based study

Visceral adipose tissue (VAT) is an independent risk factor for metabolic and cardiovascular disorders. There has been no study that demonstrated different abdominal fat distribution between Asian and Caucasian men. As the Japanese are less obese but more susceptible to metabolic disorders than Caucasians, they may have larger VAT than Caucasians at similar levels of obesity. We compared the abdominal fat distribution of the Japanese (n=239) and Caucasian-American (n=177) men aged 40-49 years in groups stratified by waist circumference in a population-based sample. We obtained computed tomography images and determined areas of VAT and subcutaneous adipose tissue (SAT). We calculated VAT to SAT ratio (VSR). The Japanese men had a larger VAT and VSR in each stratum, despite substantially less obesity overall. In multiethnic studies, difference in abdominal fat distribution should be considered in exploring factors related to obesity.     

Glucocorticoid metabolism within superficial subcutaneous rather than visceral adipose tissue is associated with features of the metabolic syndrome in South African women

OBJECTIVE: Glucocorticoid hyperactivity in adipose tissue, due to up-regulation of local glucocorticoid reactivation by 11beta-hydroxysteroid dehydrogenase-1 (11HSD1) or of glucocorticoid receptors (GR), may underpin susceptibility to the metabolic syndrome. This hypothesis has been tested extensively in subcutaneous adipose tissue (SAT) but inadequately in visceral adipose tissue (VAT). The aim of the study was therefore to examine expression of 11HSD1, GRalpha and hexose-6-phosphate dehydrogenase (H6PDH), which supplies cofactor for 11HSD1, in abdominal adipose tissue compartments and to characterize their relation to metabolic syndrome parameters. DESIGN AND SUBJECTS: A cross-sectional study including 26 premenopausal South African women. MEASUREMENTS: Biopsies were taken for measurement of mRNA levels by real-time polymerase chain reaction (RT-PCR) and 11HSD1 activity from VAT, and deep and superficial SAT compartments during elective surgery. Prior to surgery, blood pressure, blood lipid profile, body composition [by dual X-ray absorptiometry (DEXA) scan], body fat distribution [by computed tomography (CT) scan], and glucose tolerance were determined. RESULTS: 11HSD1 activity (P < 0.01) was higher in VAT than SAT, but 11HSD1 and GRalpha mRNA levels were not statistically different between compartments. 11HSD1 mRNA levels in superficial SAT correlated with VAT volume (R = 0.57, P < 0.01), insulin sensitivity calculated from the oral glucose tolerance test (OGTT) (R = -0.52, P < 0.016) and blood pressure (R = 0.48, P < 0.016). Apart from a correlation between deep SAT 11HSD1 activity and blood pressure (R = 0.72, P < 0.01), glucocorticoid action in deep SAT and VAT depots was not significantly associated with any metabolic syndrome parameters. CONCLUSION: Increased capacity for glucocorticoid regeneration in superficial SAT but not VAT is associated with visceral adiposity and other features of the metabolic syndrome in women.     

Visceral/epicardial adiposity in nonobese and apparently healthy young adults: Association with the cardiometabolic profile

Objective

We investigate associations of regional adipose tissues with cardiometabolic profile of nonobese and apparently healthy young adults.

Methods

Four hundred twenty-five nonobese and apparently healthy individuals were assessed for blood pressure and fasting lipid profile, blood glucose and adiponectin. Subcutaneous abdominal adipose tissue (SAT) and ectopic fat depots (visceral abdominal adipose tissue [VAT], epicardial adipose tissue [EAT] and hepatic fat fraction [HFF]) were quantified by magnetic resonance imaging.

Results

According to anthropometric measurements, blood pressure and blood markers, the population (18–35 years, 54% women) had a low cardiometabolic risk. Compared to women, men had more VAT, EAT and HFF, but less SAT. Regional adipose tissues were positively correlated with each other. VAT and EAT carried significant correlations with all markers of cardiometabolic risk, while SAT and HFF correlated variably with these markers. While taking into account age and gender, SAT, VAT and EAT were associated with most cardiometabolic markers, while HFF was only associated with total cholesterol/high-density lipoprotein ratio (TC/HDL-C) and triglycerides (TG). When comparing SAT, VAT and EAT head-to-head, VAT was the only adipose tissue location maintaining significant association with most markers of cardiometabolic risk. Greater VAT (≥50th percentile) was associated with a worse cardiometabolic profile, whether individuals were overweight or normal weight.

Conclusion

Even in nonobese and apparently healthy young women and men, accumulation of ectopic visceral adiposity in general, and of VAT in particular, is associated with a worse cardiometabolic profile whether individuals were overweight or normal weight.     

Relationship of visceral adipose tissue to metabolic risk factors for coronary heart disease: is there a contribution of subcutaneous fat cell hypertrophy?

Visceral adipose tissue (VAT) accumulation is an important correlate of the metabolic complications found in obese patients. The aim of this study was to evaluate the respective contribution of VAT deposition versus subcutaneous abdominal or femoral fat cell hypertrophy as correlates of the metabolic risk profile in 69 men and 65 premenopausal women (aged 35+/-5 years) with a wide range of fatness (body mass index, 18 to 57 kg/m2). In both genders, VAT accumulation was positively correlated with fasting plasma insulin, triglyceride (TG), and low-density lipoprotein (LDL)-apolipoprotein B (apo B) levels and the cholesterol (CHOL)/high-density lipoprotein (HDL)-CHOL ratio (.24 < or = r < or = .71, P < .05). A similar pattern of positive relationships was found between subcutaneous abdominal fat cell weight and metabolic risk variables in men and women (.33 < or = r < or = .60, P < .01). Positive associations were also observed in women between femoral fat cell weight and fasting plasma insulin, TG, and CHOL levels and the CHOL/HDL-CHOL ratio (.29 < or = r < or = .42, P < .05). However, only plasma TG concentrations and the CHOL/HDL-CHOL ratio were positively correlated with femoral fat cell weight in men (r = .30, P < .05). To better investigate the relationships between the metabolic risk profile and hypertrophic subcutaneous obesity, individuals with small versus large subcutaneous abdominal adipocytes were matched according to VAT accumulation. Men with large abdominal fat cells displayed higher plasma TG and LDL-apo B levels compared with men characterized by small abdominal adipocytes (P < .05). Stepwise multiple regression analyses showed that subcutaneous abdominal fat cell weight was the best independent variable predicting plasma TG and LDL-apo B levels in men. No significant difference was found in the metabolic profile of subjects displaying small versus large femoral adipocytes. Taken together, these results suggest that for a given VAT deposition, the presence of hypertrophied subcutaneous abdominal adipocytes in men appears to be associated with further deterioration in the metabolic risk profile. On the other hand, the hypertrophy of femoral adipocytes does not further alter the metabolic complications generally related to obesity in both men and women.     

Contributions of total body fat, abdominal subcutaneous adipose tissue compartments, and visceral adipose tissue to the metabolic complications of obesity

Obesity is related to the risk for developing non-insulin-dependent diabetes mellitus (NIDDM), hypertension, and cardiovascular disease. Visceral adipose tissue (VAT) has been proposed to mediate these relationships. Abdominal subcutaneous adipose tissue (SAT) is divided into 2 layers by a fascia, the fascia superficialis. Little is known about the radiologic anatomy or metabolic correlates of these depots. The objective of this study was to relate the amounts of VAT, SAT, deep subcutaneous abdominal adipose tissue (DSAT), and superficial subcutaneous abdominal adipose tissue (SSAT) to gender and the metabolic complications of obesity after adjusting for total body fat and to discuss the implications of these findings on the measurement of adipose tissue mass and adipose tissue function. The design was a cross-sectional database study set in a nutrition research center. Subjects included 199 volunteers participating in nutrition research protocols who also had computed tomography (CT) and dual energy x-ray absorptiometry (DEXA) measurement of body fat. The amount of DSAT was sexually dimorphic, with women having 51% of the subcutaneous abdominal fat in the deep layer versus 66% for men (P <.05). Abdominal fat compartments were compared with metabolic variables before and after adjusting for body fat measured by DEXA using 2 separate methods. The unadjusted correlation coefficients between the body fat measures, R(2), were largest for fasting insulin and triglyceride and smaller for high-density lipoprotein (HDL) cholesterol and blood pressure. A large portion of the variance of fasting insulin levels in both men and women was explained by total body fat. In both men and women, the addition of VAT and subcutaneous abdominal adipose tissue depots only slightly increased the R(2). In men, when body fat compartments were considered independently, DSAT explained a greater portion of the variance (R(2) =.528) in fasting insulin than VAT (R(2) =.374) or non-VAT, non-DSAT subcutaneous adipose tissue (R(2) =.375). These data suggest that total body fat is a major contributor to the metabolic sequelae of obesity, with specific fat depots, VAT, and DSAT also making significant contributions.     

Distribution of adipose tissue: quantification and relationship with hepatic steatosis and vascular profiles of type 2 diabetic patients with metabolic syndrome

AIM: As the distribution of fat is increasingly related to cardiovascular events, we examined whether or not abdominal-fat quantification using magnetic resonance imaging (MRI) software is reliable, and whether or not it is related to clinical markers of fat distribution as well as to metabolic and vascular status. METHODS: We recorded the anthropometric measurements of 34 obese type 2 diabetic patients with metabolic syndrome. The patients were enrolled to evaluate their abdominal (visceral and subcutaneous) adipose tissue by single-slice L3-L4 MRI. Manual and automated analyses were compared. The relationships between anthropometric measurements, biological markers and intima-media thickness of the common carotid artery were also assessed. RESULTS: We validated the automated software to quantify abdominal-fat deposition with MRI compared with manual measurements (r2=0.95). The waist-to-hip-circumference ratio (WHR) was the only clinical parameter that correlated with the proportion and quantity of visceral and subcutaneous abdominal-adipose tissue evaluated by MRI (r=0.60). In addition, fat repartition as evaluated by WHR was related to hepatic steatosis parameters (ferritin and ALAT) and to intima-media thickness, whereas simple waist circumference was not a determinant in these obese patients. We also showed that the adiponectin-to-leptin ratio was related to adipose tissue distribution. CONCLUSION: Distribution of abdominal fat, as evaluated by MRI, can be reflected by clinical determination of the WHR. Differences in regional accumulations of abdominal fat may be specifically related to variations in the risks of steatosis and vascular rigidity among obese type 2 diabetic patients.     

Metabolic syndrome associates with left atrial dysfunction

Background and aims

Obesity and metabolic syndrome (MetS) are risk factors of atrial fibrillation (AF), but limited data exist on their effect on left atrial (LA) function. The aim of the study was to evaluate the effects of cardiac, hepatic and intra-abdominal ectopic fat depots and cardiometabolic risk factors on LA function in non-diabetic male subjects.

Epicardial adipose tissue and insulin resistance in obese subjects

CONTEXT: Epicardial adipose tissue has been recently recognized as a source of bioactive molecules as well as free fatty acids, adiponectin, and inflammatory cytokines. Epicardial fat reflects intraabdominal visceral fat, and the echocardiographic assessment of this tissue is an easy and reliable marker of visceral adiposity. OBJECTIVE: In this study we evaluated whether epicardial adipose tissue is related to insulin sensitivity and glucose metabolism in obese subjects. PATIENTS: Thirty obese subjects (20 women and 10 men; mean age, 40.8 +/- 11.5 yr; body mass index, 43 +/- 9.1 kg/m2) were included in this study. No subject was taking drugs or had a history or evidence of metabolic, cardiovascular, respiratory, or hepatic disease. MAIN OUTCOME MEASURES: Each subject underwent a transthoracic echocardiogram to evaluate epicardial adipose tissue thickness, a euglycemic hyperinsulinemic clamp to estimate insulin sensitivity, and an oral glucose tolerance test to evaluate glucose tolerance. RESULTS: The thickness of the epicardial adipose tissue on the right ventricle varied between 4 and 17.4 mm. Echocardiographic epicardial adipose tissue was significantly correlated with whole-body glucose uptake index from the clamp and with all indices of insulin resistance and glucose intolerance measured, except the 120-min plasma glucose level after an oral glucose tolerance test. CONCLUSIONS: Our study showed that the epicardial fat is significantly related to obesity-related insulin resistance. This finding could be of potential interest in clinical practice and research of obesity-related risk stratification.     

Insulin resistance but not visceral adipose tissue is associated with plasminogen activator inhibitor type 1 levels in overweight and obese premenopausal African-American women

OBJECTIVE: To compare plasma plasminogen activator inhibitor type 1 (PAI-1) levels and to examine the association of PAI-1 with visceral adiposity and other components of the metabolic syndrome in overweight and obese premenopausal African-American (AA) and Caucasian (CC) women. DESIGN: Cross-sectional study. SUBJECTS: 33 CC and 23 AA healthy, overweight and obese, premenopausal women (age 19-53 y, body mass index 28.1-48.9 kg/m(2)). MEASUREMENTS: Body mass index, sagittal diameter, waist circumference, percentage body fat, visceral and subcutaneous adipose tissue (by anthropometry, magnetic resonance imaging (MRI), and bioelectric impedance techniques), PAI-1, leptin, lipids, glucose, insulin, and insulin resistance (by HOMA IR). RESULTS: AA women had lower triglyceride levels and less visceral adipose tissue (VAT) volume than CC despite similar BMI. PAI-1 levels were not significantly different in the two groups. Insulin resistance was associated with PAI-1 in both groups but only in CC women were VAT, triglyceride, HDL cholesterol and blood pressure related to plasma PAI-1 levels. Multiple regression analysis showed that VAT in CC and insulin resistance in AA were independent predictors of PAI-1. CONCLUSION: VAT is significantly associated with circulating PAI-1 levels in overweight and obese CC but not AA premenopausal women.     

Testosterone therapy prevents gain in visceral adipose tissue and loss of skeletal muscle in nonobese aging men

BACKGROUND: Trials of testosterone therapy in aging men have demonstrated increases in fat-free mass (FFM) and skeletal muscle and decreases in fat mass (FM) but have not reported the impact of baseline body composition. OBJECTIVE: The objective of the study was to determine the effect, in nonobese aging men with symptoms of androgen deficiency and low-normal serum testosterone levels, of testosterone therapy on total and regional body composition and hormonal and metabolic indices. METHODS: Sixty healthy but symptomatic, nonobese men aged 55 yr or older with total testosterone (TT) levels less than 15 nm were randomized to transdermal testosterone patches or placebo for 52 wk. Body composition, by dual-energy x-ray absorptiometry (FM, FFM, skeletal muscle) and magnetic resonance imaging (abdominal sc and visceral adipose tissue, thigh skeletal muscle, and intermuscular fat) and hormonal and metabolic parameters were measured at wk 0 and 52. RESULTS: Serum TT increased by 30% (P = 0.01), and LH decreased by 50% (P < 0.001). Relative to placebo, total body FFM (P = 0.03) and skeletal muscle (P = 0.008) were increased and thigh skeletal muscle loss was prevented (P = 0.045) with testosterone therapy and visceral fat accumulation decreased (P = 0.001) without change in total body or abdominal sc FM; change in visceral fat was correlated with change in TT levels (r2 = 0.36; P = 0.014). There was a trend to increasing total and low-density lipoprotein cholesterol with placebo. CONCLUSION: Testosterone therapy, relative to placebo, selectively lessened visceral fat accumulation without change in total body FM and increased total body FFM and total body and thigh skeletal muscle mass. Further studies are needed to determine the impact of these body compositional changes on markers of metabolic and cardiovascular risk.