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1.
Increased visceral adipose tissue is thought to contribute to impaired glucose tolerance. We studied 10 men with non-insulin dependent diabetes (NIDDM) before and after a 12-week intervention study using dexfenfluramine. Subjects had a mean body mass index (BMI) of 26.4 ± 1.7 kg\m2 and had an abdominal distribution of body fatness (waist-to hip ratio >0.9). Anthropometric indices, biochemistry, macronutrient intake from 7-day food records as well as a euglycaemic glucose clamp and magnetic resonance imaging (MRI) were performed at week 0 and week 12. Abdominal adipose tissue area measured by MRI was reduced from 854 ± 270 cm2 to 666 ± 231 cm2 (p=0.003) due mainly to a selective 32% reduction in visceral fat area from 484 ± 230 cm2 to 333 ± 72 cm2 (p=0.002). Insulin sensitivity improved from 0.29 ± 0.13 [min?1 (mU/L)] to 0.54 ± 0.21 [min?1 (mU/L)] (p=0.01) and C-peptide levels reduced from 0.77 ± 0.24 μmol/L to 0.58 ± 0.15 μmol/L (p=0.002). The reductions in fasting glucose and glycated haemoglobin failed to achieve significance. Fasting total cholesterol and triglyceride levels significantly reduced (p=<0.001 and p=0.021 respectively). There was a reduction in total energy intake (p=0.005) due to a significant reduction in calories obtained from fat (p<0.001). Thus dexfenfluramine was shown to be a useful adjunct therapy for the reduction of visceral fat in abdominally-obese men with NIDDM with an associated improvement in insulin sensitivity.  相似文献   

2.
Objective: To determine the ability of air displacement plethysmography (ADP) to predict visceral adipose tissue (VAT) volume in children. Research Methods and Procedures: Fifty‐five (33 boys/22 girls) white children 13 to 14 years old were studied. Anthropometric measures were collected for body mass, stature, BMI, and waist‐to‐hip ratio (WHR), and body fat percentage was estimated from triceps and subscapular skinfolds, bioelectrical impedance analysis, and ADP. VAT volume was determined using magnetic resonance imaging, using a multiple slice protocol at levels L1 to L5. Results: Boys had significantly (p ≤ 0.05) less VAT volume than girls [645.1 (360.5) cm3 vs. 1035.8 (717.3) cm3]. ADP explained the greatest proportion of the variance in VAT volume compared with the other anthropometric measures. Multiple regression analysis indicated that VAT volume was best predicted by ADP body fat percentage in boys [r2 = 0.81, SE of the estimate (SEE) = 160.1, SEE coefficient of variation = 25%] and by WHR and BMI in girls (r2 = 0.80, SEE = 337.71, SEE coefficient of variation = 33%). Discussion: Compared with the other anthropometric measures, ADP explains the greatest proportion of the variance in VAT volume in children 13 to 14 years old. For boys, ADP is the tool of choice to predict VAT volume, yet using the more simply collected measures of BMI and WHR is recommended for girls. However, large SE of the estimates remained, suggesting that if precision is needed, there is no surrogate for direct imaging of VAT.  相似文献   

3.
Recent advances in imaging techniques and understanding of differences in the molecular biology of adipose tissue has rendered classical anatomy obsolete, requiring a new classification of the topography of adipose tissue. Adipose tissue is one of the largest body compartments, yet a classification that defines specific adipose tissue depots based on their anatomic location and related functions is lacking. The absence of an accepted taxonomy poses problems for investigators studying adipose tissue topography and its functional correlates. The aim of this review was to critically examine the literature on imaging of whole body and regional adipose tissue and to create the first systematic classification of adipose tissue topography. Adipose tissue terminology was examined in over 100 original publications. Our analysis revealed inconsistencies in the use of specific definitions, especially for the compartment termed “visceral” adipose tissue. This analysis leads us to propose an updated classification of total body and regional adipose tissue, providing a well‐defined basis for correlating imaging studies of specific adipose tissue depots with molecular processes.  相似文献   

4.
OWENS, SCOTT, MARK LITAKER, JERRY ALLISON, SHARON RIGGS, MICHAEL FERGUSON, AND BERNARD GUTIN. Prediction of visceral adipose tissue from simple anthropometric measurements in youths with obesity. Obes Res. 1999;7:16–22. Objective : Although visceral adipose tissue (VAT) is the component of body composition most highly associated with cardiovascular risk factors, its measurement requires expensive procedures, such as magnetic resonance imaging. This study examined the ability of simple demographic and anthropometric measurements to predict magnetic resonance imaging-derived VAT in 76 apparently healthy, black and white youths with obesity who were 7 years to 16 years of age. Research Methods and Procedures : Stepwise multiple linear regression was used to develop a prediction equation for VAT based on 13 simple anthropometric variables (height, weight, body mass index, triceps skinfold, calf skinfold, sagittal diameter, waist circumference, hip circumference, thigh circumference, waist/hip ratio, waist/thigh ratio, sagittal diameter/thigh ratio, and percent body fat from the sum of calf and triceps skinfolds) and three demographic variables (age, gender and ethnicity). Results : The stepwise multiple regression procedure yielded a final model that included two anthropometric variables (sagittal diameter and waist/hip ratio) and one demographic variable (ethnicity). The prediction equation was: VAT = ?124.06+16.67 (ethnicity)+4.15 (sagittal diameter)-+17.89 (waist/hip ratio), where ethnicity was coded as 0 = black and 1 = white. The model explained 63% of the variance in VAT and was associated with a measurement error of 23.9%. Discussion : Although the model seems to lack sufficient explanatory power for routine use in clinical settings with individual patients, it may have some utility in epidemiological studies given its relatively small (<25%) standard error of estimate.  相似文献   

5.
Objective: To determine the effects of fat gain, time, and race on the accumulation of visceral adipose tissue (VAT) in a group of normal‐weight premenopausal women. Research Methods and Procedures: Sixty‐five women participated in the study (32 African American and 33 white). The mean age of subjects was 34 ± 6 years (range, 22 to 47 years). Eligible subjects were women who had body mass indices <25 kg/m2 at baseline and who had completed evaluations at baseline and at follow‐up year 1, without intervention. A subset of subjects was reevaluated annually for up to 4 years. Body composition was assessed by DXA, and VAT was determined from a single computed tomography scan. A linear mixed model was used to examine changes in VAT over time, with total body fat as a covariate Results: Total fat mass was not significantly different between races at baseline and increased significantly in both groups over time (p < 0.001). Time‐related increases in total body fat were greater in African‐American women (p < 0.01). VAT was significantly higher in white women at baseline (p < 0.01) and increased significantly over time in both races (p < 0.01), but remained higher in white women (p < 0.001). Increases in VAT, relative to total body fat, were greater than the increases in total body fat over time, independent of age and race (p < 0.001). Discussion: Gaining total body‐fat mass results in a higher increase in VAT, relative to total body fat, regardless of race and age, although African‐American women maintain a lower VAT levels across time.  相似文献   

6.
Objective: Previous studies have reported racial differences in the amount of visceral adipose tissue (VAT), a risk factor for metabolic diseases. These results are equivocal and have not controlled for hormonal influences on VAT mass. This study was designed to measure the extent to which race is associated with VAT, controlling for total adipose tissue (TAT) mass and testosterone. Research Methods and Procedures: Using a cross‐sectional study design, we measured TAT mass using DXA, VAT and subcutaneous adipose tissue mass using magnetic resonance imaging, and sex hormones using radioimmunoassay in 224 African‐American and white men and women. Results: White men had increased VAT mass, even when controlling for TAT and age, compared with African‐American men. White women also had a higher VAT mass compared with African‐American women, but only when controlling for TAT and age. When multiple linear regression was used to evaluate the racial differences in VAT mass in a subset of subjects (n = 80), controlling for sex hormones, it was found that white men, but not women, had increased VAT mass compared with their African‐American counterparts. Discussion: Based on the results of this study, we conclude that, when controlling for TAT, sex hormone levels, and age, white men, but not women, have more VAT mass than African‐American men and women. Additional studies are needed to explore possible environmental and genetic influences on fat distribution relative to race and sex.  相似文献   

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Objective: The contribution of visceral adipose tissue (VAT) to insulin resistance is well‐established; however, the role of subcutaneous abdominal adipose tissue (SAT) in insulin resistance remains controversial. Sex may determine which of these two components of abdominal obesity is more strongly related to insulin resistance and its consequences. The aim of this study was to determine whether both VAT and SAT contribute to insulin resistance in African Americans and to examine the effects of sex on this relationship. Research Methods and Procedures: This was a cross‐sectional study of 78 nondiabetic African‐American volunteers (44 men, 35 women; age 33.8 ± 7.3 years; BMI 30.9 ± 7.4 kg/m2). VAT and SAT volumes were measured using serial computerized tomography slices from the dome of the diaphragm to the iliac crest. The insulin sensitivity index (SI) was determined from the minimal model using data obtained from the frequently sampled intravenous glucose tolerance test. Results: In men, both VAT and SAT were negatively correlated with SI (r for both correlations = ?0.57; p < 0.01). In women, the correlation coefficient between VAT and SI was ?0.50 (p < 0.01) and between SAT and SI was ?0.67 (p < 0.01). In women, the correlation coefficient for SI with SAT was significantly greater than the correlation coefficient with VAT (p = 0.02). Discussion: Both SAT and VAT are strongly correlated with insulin resistance in African Americans. For African‐American women, SAT may have a greater effect than VAT on insulin resistance.  相似文献   

9.
Objective: To compare ethnic differences in visceral adipose tissue (VAT), assessed by computed tomography, and type 2 diabetes risk among 55‐ to 80‐year‐old Filipino, African‐American, and white women without known cardiovascular disease. Research Methods and Procedures: Subjects were participants in the Rancho Bernardo Study (n = 196), the Filipino Women's Health Study (n = 181), and the Health Assessment Study of African‐American Women (n = 193). Glucose and anthropometric measurements were assessed between 1995 and 2002. Results: African‐American women had significantly higher age‐adjusted BMI (29.7 kg/m2) and waist girth (88.1 cm) compared with Filipino (BMI, 25.5 kg/m2; waist girth, 81.9 cm) or white (BMI: 26.0 kg/m2; waist girth: 80.7 cm) women. However, VAT was significantly higher among Filipino (69.1 cm3) compared with white (62.3 cm3; p = 0.037) or African‐American (57.5 cm3, p < 0.001) women. VAT correlated better with BMI (r = 0.69) and waist (r = 0.77) in whites, compared with Filipino (r = 0.42; r = 0.59) or African‐American (r = 0.50; r = 0.56) women. Age‐adjusted type 2 diabetes prevalence was significantly higher in Filipinas (32.1%) than in white (5.8%) or African‐American (12.1%) women. Filipinas had higher type 2 diabetes risk compared with African Americans [adjusted odds ratio, 2.30; 95% confidence interval (CI), 1.09 to 4.86] or whites (adjusted odds ratio, 7.51; 95% CI, 2.51 to 22.5) after adjusting for age, VAT, exercise, education, and alcohol intake. Discussion: VAT was highest among Filipinas despite similar BMI and waist circumference as whites. BMI and waist circumference were weaker estimates of VAT in Filipino and African‐American women than in whites. Type 2 diabetes prevalence was highest among Filipino women at every level of VAT, but VAT did not explain their elevated type 2 diabetes risk.  相似文献   

10.
Reliably differentiating brown adipose tissue (BAT) from other tissues using a non-invasive imaging method is an important step toward studying BAT in humans. Detecting BAT is typically confirmed by the uptake of the injected radioactive tracer 18F-Fluorodeoxyglucose (18F-FDG) into adipose tissue depots, as measured by positron emission tomography/computed tomography (PET-CT) scans after exposing the subject to cold stimulus. Fat-water separated magnetic resonance imaging (MRI) has the ability to distinguish BAT without the use of a radioactive tracer. To date, MRI of BAT in adult humans has not been co-registered with cold-activated PET-CT. Therefore, this protocol uses 18F-FDG PET-CT scans to automatically generate a BAT mask, which is then applied to co-registered MRI scans of the same subject. This approach enables measurement of quantitative MRI properties of BAT without manual segmentation. BAT masks are created from two PET-CT scans: after exposure for 2 hr to either thermoneutral (TN) (24 °C) or cold-activated (CA) (17 °C) conditions. The TN and CA PET-CT scans are registered, and the PET standardized uptake and CT Hounsfield values are used to create a mask containing only BAT. CA and TN MRI scans are also acquired on the same subject and registered to the PET-CT scans in order to establish quantitative MRI properties within the automatically defined BAT mask. An advantage of this approach is that the segmentation is completely automated and is based on widely accepted methods for identification of activated BAT (PET-CT). The quantitative MRI properties of BAT established using this protocol can serve as the basis for an MRI-only BAT examination that avoids the radiation associated with PET-CT.  相似文献   

11.
Adipose tissue is a connective tissue specified for energy metabolism and endocrines, but functional differences between subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) have not been fully elucidated. To reveal the physiological role of SAT, we characterized in vivo tissue development and in vitro adipocyte differentiation. In a DNA microarray analysis of SAT and VAT in Wistar rats, functional annotation clusters of extracellular matrix (ECM)-related genes were found in SAT, and major ECM molecules expressed in adipose tissues were profiled. In a histological analysis and quantitative expression analysis, ECM expression patterns could be classified into two types: (i) a histogenesis-correlated type such as type IV and XV collagen, and laminin subunits, (ii) a high-SAT expression type such as type I, III, and V collagen and minor characteristic collagens. Type (i) was related to basal membrane and up-regulated in differentiated 3T3-L1 cells and in histogenesis at depot-specific timings. In contrast, type (ii) was related to fibrous forming and highly expressed in 3T3-L1 preadipocytes. Exceptionally, fibronectin was abundant in developed adipose tissue, although it was highly expressed in 3T3-L1 preadipocytes. The present study showed that adipose tissues site-specifically regulate molecular type and timing of ECM expression, and suggests that these characteristic ECM molecules provide a critical microenvironment, which may affect bioactivity of adipocyte itself and interacts with other tissues. It must be important to consider the depot-specific property for the treatment of obesity-related disorders, dermal dysfunction and for the tissue regeneration.  相似文献   

12.
Diacylglycerol acyltransferase (DGAT) could be a rate limiting step in triglyceride (TG) synthesis as it is the final step in this pathway. As such, between depot differences in DGAT activity could influence regional fat storage. DGAT activity and in vitro rates of direct free fatty acid (FFA) storage were measured in abdominal subcutaneous and omental adipose tissue samples from 12 nonobese (BMI <30 kg/m2) and 23 obese men and women (BMI >30 kg/m2) undergoing elective surgery. DGAT activity was greater in omental than in abdominal subcutaneous adipose tissue from nonobese patients (2.0 ± 0.9 vs. 0.9 ± 0.3 pmol/min/mg lipid, respectively, P = 0.003), but not from obese patients (1.4 ± 0.6 vs. 1.7 ± 0.7 pmol/min/mg lipid, respectively, P = 0.10). DGAT activity per unit adipose weight was negatively correlated with adipocyte size (P < 0.01) and positively correlated with direct FFA storage in omental (P < 0.001) but not in abdominal subcutaneous fat. Tissue DGAT activity varies as a function of adipocyte size, but this relationship differs between visceral and abdominal subcutaneous fat in obese and nonobese humans. Our results are consistent with the hypothesis that interindividual variations in DGAT activity may be an important regulatory step in visceral adipose tissue FFA uptake/storage.  相似文献   

13.
Regional fat distribution rather than overall fat volume has been considered to be important to understanding the link between obesity and metabolic disorders. We aimed to evaluate the independent associations of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with metabolic risk factors in apparently healthy middle‐aged Japanese. Participants were 1,119 men and 854 women aged 38–60 years who were not taking medications for diabetes, hypertension, or dyslipidemia. VAT and SAT were measured by use of computed tomography (CT) scanning. VAT and SAT were significantly and positively correlated with each other in men (r = 0.531, P < 0.001) and women (r = 0.589, P < 0.001). In multiple regression analyses, either measure of abdominal adiposity (VAT or SAT) was positively associated with blood pressure, fasting plasma glucose, and log triglyceride (P < 0.001) and inversely with high‐density lipoprotein (HDL)‐cholesterol (P < 0.001). When VAT and SAT were simultaneously included in the model, the association of VAT with triglycerides was maintained (P < 0.001) but that of SAT was lost. The same was true for HDL‐cholesterol in women. For fasting plasma glucose, the association with VAT was strong (P < 0.001) and the borderline association with SAT was maintained (P = 0.060 in men and P = 0.020 in women). Both VAT and SAT were independently associated with blood pressure (P < 0.001). Further adjustment for anthropometric indices resulted in the independent association only with VAT for all risk factors. In conclusion, impacts of VAT and SAT differed among risk factors. VAT showed dominant impacts on triglyceride concentrations in both genders and on HDL‐cholesterol in women, while SAT also had an independent association with blood pressure.  相似文献   

14.
Objective: To examine differences in body size, composition, and distribution of body fat among Hispanic, white, and Asian adolescents. Research Methods and Procedures: This included cross‐sectional data from the baseline sample of the Adequate Calcium Today trial. Participants included 180 Asian, 234 Hispanic, and 325 white girls 11.8 ± 0.05 years of age from Arizona, California, Hawaii, Indiana, Ohio, and Nevada. Anthropometric and DXA measurements (Lunar Prodigy) were standardized across sites. Tanner pubertal stage was self‐selected from line drawings. Physical activity was assessed by a validated questionnaire. Comparisons between ethnic groups were examined using contrasts in the context of a general linear model. Results: Controlling for pubertal stage and study site only, Asians weighed less than Hispanics and were shorter than Hispanics and whites. Controlling for pubertal stage, height, weight, and study site, Asians had shorter leg lengths, smaller waist circumference, longer trunk lengths, more lean mass, less total fat mass, and less gynoid fat mass than Hispanics and whites; Asians had larger bitrochanteric width than whites; Asians had smaller DXA‐derived android fat mass than Hispanics; and whites had smaller mean android/gynoid fat ratio than Hispanics. However, whites had a smaller android/gynoid fat ratio than both Asians and Hispanics in a model that adjusted for ethnicity, pubertal stage, bitrochanteric width, waist circumference, trunk length, log of physical activity, and study site, which explained 77% of the variation. Discussion: Ethnic differences in fat distribution are partially explained by differences in skeletal dimensions.  相似文献   

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Objective: Physical inactivity, abdominal fat, and age are known risk factors for diabetes, cardiovascular disease, and certain cancers. Previous evidence supports an inverse relationship between physical activity (PA) and abdominal fat estimated by waist circumference. However, few investigations used computed tomography (CAT) scanning for precise measures of abdominal fat. Research Methods and Procedures: Sixty-five female and 106 male (age, 64.5 ± 5.2 years) participants in the Prostate, Lung, Colon and Ovarian Cancer Screening Trial underwent a cross-sectional L4–L5 CAT scan to differentiate visceral adipose tissue (VAT). Subjects were also interviewed by phone to determine PA and physical difficulties (PD). Results: Women had lower VAT (170 ± 84 vs. 205 ± 95 cm2, p = 0.014), lower VAT/total fat (29.9 ± 7.2% vs. 42.6 ± 10.2%, p < 0.001), and higher total fat (596 ± 385 vs. 482 ± 183 cm2, p = 0.010) than men. PA was inversely correlated to VAT (r = −0.164, p = 0.034) and total fat (r = −0.231, p = 0.003) in men and women. Those who reported a PD had higher VAT (249 vs. 180 cm2, p < 0.001) and total fat (652 vs. 500 cm2, p = 0.008). Multiple regression analysis indicated total PA and PD were independently associated to VAT and total fat. Discussion: This investigation suggests a beneficial effect of PA and a negative influence of PD on abdominal fat accumulation. Although the cross-sectional design limits cause-effect designations, these results are consistent with other studies showing PA/abdominal fat relation.  相似文献   

17.
Despite the established link between visceral obesity and major chronic diseases, little is known about physiologic factors that directly and specifically lead to the accumulation of visceral fat. I hypothesize that reduced intra-abdominal temperature might be a physical factor underlying the partitioning of adipose tissue to the intra-abdominal region rather than the periphery. The hypothesis is supported by biochemical reports that rat and bovine lipoprotein lipase have increased activity when incubated at lower temperatures. Persons exercising in cool water have been found to preserve subcutaneous fat whereas comparable exercise without local cooling results in subcutaneous fat loss. Pima Indians, a group that commonly acquires extreme levels of visceral fat, have been found to have lower intraabdominal temperatures during sleep than weight-matched European-Americans. In a study of four young men and four young women, I have noted that mean intra-abdominal basal temperatures were higher for women than men (36.51 ± 0.18°C vs. 35.91 ± 0.11°C; p = .0014). Since the men are more likely to acquire visceral obesity at later age, this also provides support for my hypothesis. Investigators might wish to examine further the temperature dependence of adipose-tissue lipoprotein lipase, the temperature variation between sites of adipose tissue, and the effects of foods, physical activities, smoking and drugs on localized body temperature.  相似文献   

18.
Central fat distribution and more recently intra abdominal adipose tissue (IAF) have been associated with elevated cardiovascular risk factors (CRF). Despite increased interest in use of IAF for screening for CRF, interpretation of risk found in a specific IAF is difficult since regressions for estimating CRF from IAF have not been published. The purpose of this paper is to report IAF values that are likely to be associated with elevated CRF. One hundred forty-six healthy male subjects 30–71 years were evaluated for IAF and subcutaneous fat (computed tomography scan at 4th lumbar vertebra), height, body weight, % fat, various anthropometric measures, blood cholesterol (CHOL), HDL cholesterol (HDL), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Receiver-Operating-Characteristic curves (ROC) were used to develop IAF cutpoints associated with elevation of at least one established CRF criteria (CHOL=200, HDL=<35, SBP=140, DBP=90). A sensitivity/(1- specificity) curve estab lished the value of using IAF cutpoints for detecting elevated CRF. Likelihood ratios were used to identify optimal cutpoints. Two cutpoints were identified, 131 cm2 with a relatively high Lpos ratio and 71 cm2with a relatively low Lneg. False positives associated with 131 cm2 were 14% for one or more elevated CRF. False negatives associated with 71 cm2 were 9% for one or more elevated CRF, 4% for two or more CRF, and 0% for three or more elevated CRF. This study clearly indicates that IAF above 131 cm2is related to elevated CRF and IAF below 71 cm2 is associated with reduced cardiovascular risk.  相似文献   

19.
目的:既往研究显示SePP1具有一定的抗氧化作用,而随着年龄的增加机体逐步出现一个慢性低氧、炎症状态,我们通过4%O2浓度体外培养大鼠脂肪前体细胞模拟其体内的低氧状态,进而观察常氧(21%O2)及低氧(4%02)状态下大鼠脂肪前体细胞中炎症因子(IL-6,MCP-1,SePP1)水平的变化及不同状态下硒蛋白SePP1水平的变化。方法:取6—8周SD大鼠肾周脂肪前体细胞,分别于常氧(21%O2)及低氧(4%O2)状态下进行体外培养,诱导分化后采用油红0染色进行鉴定,至第三代后,分别采用PCR及Westem Blot技术检测两种状态下脂肪前体细胞中1L-6,MCP-1,SePPl基因及蛋白表达的不同变化,同时观察不同氧浓度对脂肪前体细胞增殖的影响。结果:4%氧浓度状态下培养的脂肪前体细胞中IL-6,MCP-1的基因及蛋白表达均明显高于正常氧浓度下的脂肪前体细胞,而SePP1的基因及蛋白表达均下降,且低氧状态下脂肪前体细胞增殖较常氧状态下加快。结论:低氧培养可进一步使机体内脏脂肪组织堆积加重,造成脂肪前体细胞的炎症状态,并且可导致SePP1的表达下降,而SePP1具有一定的抗氧化作用,与机体动脉粥样硬化等心血管疾病的发生、发展有一定的关联,本实验结论为通过干预体内SePP1的水平为靶点治疗动脉粥样硬化提供了一定的实验依据,为进一步研究SePP1在低氧状态下对动脉粥样硬化的影响及作用机制提供了一定的试验基础。  相似文献   

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