运用CT半自动分割技术分析泌尿系结石患者腹部脂肪分布特征的初步研究

目的:探讨CT半自动分割技术评价的腹部脂肪分布特征与泌尿系结石患病的相关性.方法:运用CT半自动分割技术测量泌尿系结石患者和无泌尿系结石患者的腰围(WL)、腹部最大横径(ATD)、腹部最大矢状面前后径(ASD)、皮下脂肪厚度(SAT)、腹腔内脏脂肪面积(VAA)、腹壁皮下脂肪面积(SAA)、内脏脂肪面积百分比(VAA/...     

腹部脂肪分布与肺通气功能的关系研究

目的 研究内脏脂肪面积(visceral adipose tissue area,VTA)和皮下脂肪面积(subcutaneous adipose tissue area,STA)对肺通气功能的影响,进而评估腹部脂肪分布在肺通气功能中的作用.方法 在四川大学华西医院的电子病历系统中选择2017年1月1日-12月31日既...     

原发性高血压患者内脏脂肪分布与左心室肥厚的相关性

目的通过观察原发性高血压患者腹部CT内脏脂肪/皮下脂肪比值(V/S)及体质量指数(BMI)、腰臀比(WHR)、腰围/身高比值(WHtR )与原发性高血压左心室肥厚（LVH）的关系,探讨原发性高血压患者腹部CT内脏脂肪分布与LVH的相关性。方法对80例入选者行上腹CT检查及心脏超声检查,分别测量上腹CT的V/S及心脏超声左心室质量指数（LVMI）,并记录年龄、收缩压、舒张压、BMI、WHR和WHtR,应用统计学方法观察各参数与LVMI的关系。结果原发性高血压患者LVH组与非LVH组年龄、收缩压和舒张压差异均无统计学意义（P＞0.05）,而原发性高血压患者LVH组V/S、BMI、WHR和WHtR显著高于非LVH组（P＜0.05）;V/S、WHtR、WHR和BMI与LVMI之间有线性回归关系,且V/S回归系数最大。结论肥胖对原发性高血压患者LVH有促进作用,内脏脂肪聚集与LVH关系尤为密切。     

不同运动方式对2型糖尿病患者内脏及皮下脂肪影响的Meta分析

目的系统评价有氧运动(AT)、抗阻运动(RT)及有氧联合抗阻运动(AT+RT)对2型糖尿病(T2DM)患者腹部内脏脂肪(VAT)、皮下脂肪(SAT)的影响。方法计算机检索Embase、Web of Science、MEDLINE、中国生物医学文献数据库(CBM)、中国期刊全文数据库(CNKI)、万方数字化期刊全文数据库及中文科技期刊全文数据库(VIP)中关于有氧、抗阻及联合运动对2型糖尿病患者VAT和SAT影响的随机对照试验(RCT),提取纳入研究的特征信息。用RevMan5.3软件对纳入文献数据进行Meta分析。结果最终纳入14篇文献,共864例患者。Meta分析结果显示:与对照组相比,运动可以降低T2DM患者VAT和SAT(P0.01);亚组分析结果显示,有氧、抗阻、有氧联合抗阻运动均能够显著降低T2DM患者的VAT水平(P0.05)。另外,有氧运动能够显著降低SAT水平(P0.01),然而抗阻、有氧联合抗阻运动组与对照组在降低SAT水平差异无统计学意义(P0.05)。结论三种不同运动均能够降低T2DM患者的VAT,且VAT水平降低比SAT降低效果更显著;其中有氧运动降低腹部脂肪幅度效果优于其它两种运动,抗阻及有氧联合抗阻运动有降低SAT的趋势,但考虑到此次纳入文献质量为中等,且关于抗阻和有氧联合抗阻运动对T2DM患者内脏及皮下脂肪的研究较少,因此其有效性仍需要大样本、高质量的研究进一步探讨。     

内脏脂肪组织与急性胰腺炎严重程度的相关性分析

目的：研究内脏脂肪组织（ visceral adipose tissue , VAT）和急性胰腺炎（ AP）的严重程度之间的关系,探索VAT在预测急性胰腺炎严重程度中的价值。方法回顾性收集2010－01～2013－12期间我院收治的257例急性胰腺炎病例,通过计算断层扫描图像来衡量VAT面积;其他分析因素包括年龄、性别、体质量指数（body mass index, BMI）、APACHEⅡ评分、Ranson’s评分、住院时间和死亡事件。结果56例（21.79％）患者被确诊为中度和重症急性胰腺炎。轻型胰腺炎和中度、重症急性胰腺炎内脏脂肪组织百分比（ VAT％）差异存在统计学意义（ P＝0.013）。中度和重症急性胰腺炎患者VAT％增高,VAT％与BMI没有相关性,但VAT％预测急性胰腺炎严重程度的能力优于BMI。结论 VAT增加与急性胰腺炎的严重程度密切相关。 VAT相对于BMI有着独特的预后价值,建议在急性胰腺炎早期评估中纳入VAT指标。     

MRI及1H-MRS评估针灸治疗对肥胖儿童腹部脂肪和肝内脂质含量的影响

目的 应用MRI和¹H-MRS评估针灸治疗对肥胖儿童腹部脂肪和肝内脂质含量的影响。方法 10例肥胖儿童(男7例,女3例)接受规律针灸治疗1个月,治疗前、后分别测量体质量、体质量指数(BMI)、腰围、臀围、腰臀比值(WHR)、腹部脂肪体积(应用MRI)及肝内脂质含量(应用¹H-MRS)。结果 针灸治疗后患者的BMI较治疗前减少3.50%(P=0.005)。腹腔内脂肪(VAT)体积、腹部总脂肪(TAT)体积及腹腔内脂肪/皮下脂肪比值(V／S)均较治疗前减少(P均＜0.05)。体质量、腰围、臀围、WHR、腹部皮下脂肪(SAT)体积及肝内脂质含量(IHCL) 均较治疗前减少,但差异无统计学意义(P＞0.05)。针灸治疗前后腹部脂肪体积(SAT、VAT)与人体测量参数(体质量、BMI、腰围及臀围)显著相关,而肝内脂质含量(IHCL)与人体测量参数及腹部脂肪体积等指标之间均无相关性。结论 针灸治疗可以显著减少肥胖儿童的BMI及腹部脂肪体积,特别是腹腔内脂肪体积。     

MRI在代谢综合征中的早期胰腺癌筛查中的应用

目的:探究磁共振成像(Magnetic Resonance Imaging, MRI)在代谢综合征(metabolicsyndrome, MS)中的早期胰腺癌(pancreaticcancer, PC)筛查中的临床诊断价值。方法:选取我院2020年1月至2022年12月期间在我院进行体检的90例代谢综合征患者和同期90例健康志愿者作为研究对象。90例代谢综合征患者为观察组,90例健康志愿者为对照组。利用MRI检查两组腹部脂肪分数(fatfraction, FF)值,胰腺脂肪分数(Pancreatic fat fraction, PFF)、第4、5腰椎间隙平上8cm处腔断面的下脂肪面积(Small Area, SA)、腹腔脂肪面积(visceral fat area, V A)、腹部总脂肪面积(Total abdominal fat area, T A),并计算腹部下脂肪面积比例(Proportion of the lower abdominal fat area, SFP)以及腹部内脏脂肪面积比例(Proporo of the abdominal visceral fat area, VFP)的值。结果:观察组FF值和PFF值均高于对照组,差异有统计学意义(P<0.05),观察组SA、VA、TA、SFP、VFP值均高于对照组,差异有统计学意义(P<0.05)。观察组有23例(25.56%)患有胰腺癌,对照组有8例(8.89%)患有胰腺癌,两组之间相比较,差异有统计学意义(P<0.05)。结论:代谢综合征患者中在MRI检查脂肪定量值和胰腺脂肪定量值中FF值以及PFF值以及胰腺脂肪面积的高于正常人群,且有代谢综合征患者更容易发生胰腺癌。     

腰椎骨质密度与年龄、性别、体质参数及腹部脂肪的相关性

目的 探讨腰椎骨质密度(BMD)与年龄、性别、体质参数及腹部皮下脂肪(SAT)、内脏脂肪(VAT)的关系。方法 纳入健康志愿者或慢性腰腿痛患者111人(男56人,女55人),测量受检者身高、体质量及腰围,计算体质指数(BMI);采用定量CT(QCT)行腹部扫描,测量L3的BMD及相应层面腹部SAT与VAT含量。将男性与女性分别分为骨质疏松组、骨量减少组和骨量正常组,分别比较3组间年龄、性别、身高、体质量、BMI、腰围、SAT和VAT的差异,对BMD与存在显著性差异的指标进行相关性分析。结果 3组男性间除年龄的差异有统计学意义(P<0.05)外,身高、体质量、BMI、腰围、SAT及VAT的差异均无统计学意义(P均>0.05);男性BMD与年龄呈负相关(r=-0.680,P<0.05)。3组女性年龄、腰围及VAT的差异有统计学意义(P均<0.05),身高、体质量、BMI、SAT差异均无统计学意义(P均>0.05);女性BMD与年龄、腰围、VAT均呈负相关(r= -0.849、-0.412、-0.501,P均<0.05)。结论 男、女性腰椎BMD与年龄均呈明显负相关,与身高、体质量、BMI无明显相关性;男性腰椎BMD与腰围、SAT与VAT均无明显相关性,但女性腰椎BMD与腰围及VAT关系密切。     

内脏脂肪组织在克罗恩病发病、诊断及治疗中的作用

克罗恩病(Crohn's disease,CD)是一种慢性炎性肉芽肿性疾病,多发于末端回肠和临近结肠,呈节段性分布.CD肠道病变的机制尚不完全明确,与遗传、免疫和环境等多种因素有关.脂肪组织在CD的发病中发挥重要作用,最新研究发现内脏脂肪组织(visceral adipose tissue,VAT),特别是其肠系膜成分...     

~1H MRS对初诊2型糖尿病患者胰腺脂肪沉积的量化及与胰岛β细胞功能的关系研究

目的分析胰腺脂肪含量与肝脏脂肪含量、血清甘油三酯(TG)及胰岛β细胞功能的关系。材料与方法在3.0 T磁共振系统应用单体素点分辨波谱序列(PRESS)对58例初诊2型糖尿病患者和32名无糖尿病志愿者的胰腺和肝脏进行1H MRS扫描,应用SAGE软件测量其脂肪和水的峰下面积,计算胰腺和肝脏脂肪分数。分析胰腺脂肪含量与肝脏脂肪含量、身高体重指数(BMI)、TG、空腹血糖、空腹胰岛素(FINS)、稳态模型胰岛素分泌指数(HOMA-β)、胰岛素抵抗指数(HOMA-IR)以及李-Bennett胰岛β细胞功能指数(MBCI)的相关性。结果58例初诊2型糖尿病患者和32名无糖尿病志愿者的平均胰腺脂肪分数分别为(16.09±6.27)%和(14.56±7.97)%,差异无统计学差异(P0.05)。其中,32例初诊2型糖尿病患者和全部无糖尿病志愿者成功测量肝脏脂肪分数,平均数值分别为(21.13±14.44)%和(12.43±12.19)%,差异有统计学差异(P=0.006)。相关性分析表明,初诊2型糖尿病患者的胰腺脂肪含量与肝脏脂肪含量、BMI、TG、空腹血糖、FINS、MBCI、HOMA-β及HOMA-IR均无明确相关性(r0.15,P0.05),而无糖尿病志愿者的胰腺脂肪含量与肝脏脂肪含量(r=0.502,P=0.003)、TG(r=0.467,P=0.007)及BMI(r=0.362,P=0.042)有中度至低度的相关性。结论初诊2型糖尿病患者的胰腺脂肪含量与肝脏脂肪含量、TG及胰岛β细胞功能不相关。     

Practical approach for estimation of subcutaneous and visceral adipose tissue

OBJECTIVES: The first objective was to investigate the correlations between anthropometrical measurements and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in two cohorts differing in age using magnetic resonance imaging (MRI) as reference. A second objective was to investigate the potential usage of abdominal diameters in practical estimation of adipose tissue compartments using these cohorts. METHODS: Measurements of body mass index, waist circumference, sagittal abdominal diameter (sagittal AD) and transverse abdominal diameter (transverse AD) were obtained from 336 volunteers of age 14-70 years. Manual measurements of VAT and SAT from single slice MRI at the L4-L5 level were used as reference. The abdominal diameters were measured from the MR images. Linear correlations between the anthropometrical measurements and the reference were studied. RESULTS: Sagittal AD showed the strongest correlation to VAT (r >or= 0 x 780, P<0 x 0001) and transverse AD was found to give information about the amount of SAT (r >or= 0 x 866, P<0 x 0001). The ellipse spanned by the sagittal AD and the transverse AD was strongly correlated to the total amount of adipose tissue (r >or= 0 x 962, P<0 x 0001). CONCLUSION: Strong correlations were found between sagittal and transverse abdominal diameters, assessed using MRI, and VAT and SAT, respectively. These results suggest the use of abdominal diameters in practical estimations of VAT and SAT depots.     

Insulin resistance, hepatic lipid and adipose tissue distribution in HIV-infected men

BACKGROUND: A large proportion of HIV-infected patients on antiretroviral medication develop insulin resistance, especially in the context of fat redistribution. This study investigates the interrelationships among fat distribution, hepatic lipid content, and insulin resistance in HIV-infected men. METHODS: We performed a cross-sectional analysis of baseline data from 23 HIV-infected participants in three prospective clinical studies. Magnetic resonance spectroscopy was used to quantify hepatic lipid concentrations. Magnetic resonance imaging was used to quantify whole-body adipose tissue compartments: that is, subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) volumes, as well as the intermuscular adipose tissue (IMAT) subcompartment and the omental-mesenteric adipose tissue (OMAT) and retroperitoneal adipose tissue (RPAT) subcompartments of VAT. The homeostasis model for assessment of insulin resistance (HOMA-IR) was calculated from fasting glucose and insulin concentrations. RESULTS: Hepatic lipid content correlated significantly with total VAT (r = 0.62, P = 0.0014), but not with SAT (r = 0.053, P = 0.81). In univariate analysis, hepatic lipid content was associated with the OMAT (r = 0.67, P = 0.0004) and RPAT (r = 0.53, P = 0.009) subcompartments; HOMA-IR correlated with both VAT and hepatic lipid contents (r = 0.61, P = 0.057 and r = 0.68, P = 0.0012, respectively). In stepwise linear regression models, hepatic lipid had the strongest associations with OMAT and with HOMA-IR. CONCLUSION: Hepatic lipid content is associated with VAT volume, especially the OMAT subcompartment, in HIV-infected men. Hepatic lipid content is associated with insulin resistance in HIV-infected men. Hepatic lipid content might mediate the relationship between VAT and insulin resistance among treated, HIV-infected men.     

Patterns of Abdominal Fat Distribution: The Framingham Heart Study

OBJECTIVE—The prevalence of abdominal obesity exceeds that of general obesity. We sought to determine the prevalence of abdominal subcutaneous and visceral obesity and to characterize the different patterns of fat distribution in a community-based sample.RESEARCH DESIGN AND METHODS—Participants from the Framingham Heart Study (n = 3,348, 48% women, mean age 52 years) underwent multidetector computed tomography; subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) volumes were assessed. Sex-specific high SAT and VAT definitions were based on 90th percentile cut points from a healthy referent sample. Metabolic risk factors were examined in subgroups with elevated SAT and VAT.RESULTS—The prevalence of high SAT was 30% (women) and 31% (men) and that for high VAT was 44% (women) and 42% (men). Overall, 27.8% of the sample was discordant for high SAT and high VAT: 19.9% had SAT less than but VAT equal to or greater than the 90th percentile, and 7.9% had SAT greater than but VAT less than the 90th percentile. The prevalence of metabolic syndrome was higher among women and men with SAT less than the 90th percentile and high VAT than in those with high SAT but VAT less than the 90th percentile, despite lower BMI and waist circumference. Findings were similar for hypertension, elevated triglycerides, and low HDL cholesterol.CONCLUSIONS—Nearly one-third of our sample has abdominal subcutaneous obesity, and >40% have visceral obesity. Clinical measures of BMI and waist circumference may misclassify individuals in terms of VAT and metabolic risk.Obesity is associated with an increased risk of multiple cardiometabolic risk factors. The prevalence of obesity in the U.S. has increased over the last two decades, with one-third of adults having a BMI ≥30 kg/m² (1). However, obesity is a heterogeneous condition with individual differences in the pattern of adipose tissue deposition. Accumulation of abdominal fat, particularly in the visceral compartment, may confer the majority of obesity-associated health risks (2).The prevalence of abdominal obesity (defined as waist circumference ≥88 cm in women and ≥102 cm in men) has increased over the last decade and now exceeds the prevalence of overall obesity, with rates of 42.4% in men and 61.3% in women (1,3). Notably, the largest relative increase in the prevalence of abdominal obesity has been among individuals with BMI <30 kg/m² (3). Although waist circumference is an easily obtainable index of abdominal adiposity, it does not distinguish between the subcutaneous and visceral adipose tissue compartments. We and others have previously reported that visceral adipose tissue (VAT) has a stronger association with metabolic risk factors and metabolic syndrome than subcutaneous adipose tissue (SAT) (4–6). These studies are limited, however, by the high correlations between SAT and VAT that make it difficult to distinguish between the contribution of SAT compared with that of VAT with regard to metabolic risk.Thus, the objectives of the present study were twofold. First, we sought to define the prevalence of abdominal obesity in terms of elevated volumes of VAT and SAT, as measured by a volumetric computed tomography (CT) method. To do this, we developed cut points for elevated SAT and VAT based on a healthy referent sample. Second, we examined the occurrence of different patterns of adipose tissue distribution and concomitant metabolic risk factor profiles. We hypothesized that metabolic risk factors would be more likely to track with elevated levels of VAT than with SAT.     

Effects of dietary treatment alone or diet with voglibose or glyburide on abdominal adipose tissue and metabolic abnormalities in patients with newly diagnosed type 2 diabetes

OBJECTIVE; To examine the effects of diet and diet with voglibose or glyburide on abdominal adiposity and metabolic abnormalities in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 36 Japanese patients with newly diagnosed type 2 diabetes (50.8 +/- 8.6 years of age, BMI 24.5 +/- 3.5 kg/m(2)) and 273 normal control subjects were studied. The patients were treated for 3 months with diet alone (30 kcal/kg per day) (n = 15), diet with voglibose (n = 12), or diet with glyburide (n = 9). They underwent 75-g oral glucose tolerance testing, assessment of insulin sensitivity (SI), and acute insulin response (AIR) with intravenous glucose tolerance testing based on the minimal model, and measurement of abdominal visceral adipose tissue area (VAT) and subcutaneous adipose tissue area (SAT) by computed tomography before and after treatment. RESULTS: The diabetic patients had comparable SAT but larger VAT than the control subjects. With a mean weight loss of 2-3 kg, VAT and SAT were decreased similarly in all treatment groups. The VAT-to-SAT ratio was decreased only in the voglibose group. Glycemic control and serum lipid profiles were improved in all groups. Changes in glycemic control after diet were closely correlated with changes in VAT but not with changes in SAT. SI and AIR were unchanged in the diet group but were improved in the voglibose and glyburide groups. CONCLUSIONS: In Japanese patients with newly diagnosed type 2 diabetes who were relatively lean but had excess VAT, diet with or without voglibose or glyburide effectively reduced VAT. Decrease in VAT was closely associated with improvement of glycemic control with diet. Additional use of voglibose or low-dose glyburide had no detrimental effects on abdominal adiposity and had beneficial effects on SI and AIR.     

PPARγ2 protects against obesity by means of a mechanism that mediates insulin resistance

Background  Many studies have focused on the physiological parameters and genetic predisposition of subjects presenting both obesity and insulin resistance (IR) and it has been suggested that the peroxisome proliferator-activated receptor gamma 2 (PPARγ2) Pro12Ala variant may contribute to the observed variability in insulin sensitivity. We investigated whether the PPARγ2 mRNA expression levels are associated with IR in morbid obesity in adipose and muscle tissues.
Materials and methods  In this study, tissue biopsies were obtained from 26 morbidly obese (MO) patients and eight controls. The MO patients were divided into two groups: those with a low homeostasis model assessment of IR (HOMA-IR < 5) (MO-nonIR) and those with a high HOMA-IR (HOMA-IR ≥ 8) (MO-IR). PPARγ1, PPARγ2 and aP2 mRNA expression levels were measured using quantitative RT-PCR.
Results  The study found that PPARγ2 mRNA expression in visceral adipose tissue (VAT) was significantly lower in the MO patients ( P  = 0·002) than the controls. Moreover, the PPARγ2 mRNA expression was lower in VAT ( P  < 0·05) and muscle tissue ( P  < 0·01), and higher in subcutaneous adipose tissue (SAT) ( P  < 0·01) in the MO-IR than the MO-nonIR group. By contrast, PPARγ1 mRNA expression levels were not dependent on IR. Finally, the MO patients showed a significant negative correlation between PPARγ2 mRNA expression and IR ( r  = −0·396, P  = 0·020) in VAT and a positive correlation in SAT ( r  = 0·826, P  < 0·001). The variable that best explained the IR was PPARγ2 mRNA expression in SAT ( P  = 0·002).
Conclusions  These data show that PPARγ2 mRNA is expressed differently in the two types of MO patients and is associated with IR.     

Adipose tissue distribution in relation to insulin sensitivity and inflammation in Pakistani and Norwegian subjects with type 2 diabetes

Abstract

Immigrants from South Asia to Western countries have a high prevalence of type 2 diabetes mellitus (T2DM) associated with obesity. We investigated the relationship between diabetes and adipose tissue distribution in a group of younger T2DM subjects from Norway and Pakistan. Eighteen immigrant Pakistani and 21 Norwegian T2DM subjects (age 29–45, 49% men) were included. They underwent anthropometrical measurements including bioelectrical impedance analysis, CT scans measuring fatty infiltration in liver and adipose and muscle tissue compartments in mid-abdomen and thigh, a euglycemic clamp, and blood samples for serum insulin and plasma glucose, adipokines and inflammation markers. Adipose tissue distribution was similar in Norwegians and Pakistanis. Pakistanis, but not Norwegians, showed a negative correlation between insulin sensitivity and visceral adipose tissue (VAT, r_s = ? 0.704, p = 0.003). Subcutaneous adipose tissue (SAT) correlated to leptin in both Pakistanis and Norwegians (r_s = 0.88, p < 0.001 and 0.67, p = 0.001). SAT also correlated to C-reactive protein (CRP) in the Pakistanis only (r_s = 0.55, p = 0.03), and superficial SAT to Interleukin-1 receptor antagonist (IL-1RA) in Norwegians only (r_s = 0.47, p = 0.04). In conclusion, despite similar adipose tissue distribution in the two groups Pakistanis were more insulin resistant, with a negative correlation of VAT to insulin sensitivity, not present in Norwegians. The correlation of adipose tissue to Leptin, CRP and IL-1RA showed ethnic differences.     

Abdominal Subcutaneous Adipose Tissue: A Protective Fat Depot?

OBJECTIVE

Obesity is associated with increased metabolic and cardiovascular risk. The ectopic fat hypothesis suggests that subcutaneous fat may be protective, but this theory has yet to be fully explored.

RESEARCH DESIGN AND METHODS

Participants from the Framingham Heart Study (n = 3,001, 48.5% women) were stratified by visceral adipose tissue (VAT) into sex-specific tertiles. Within these tertiles, age-adjusted abdominal subcutaneous adipose tissue (SAT) tertiles were examined in relation to cardiometabolic risk factors.

RESULTS

In the lowest VAT tertile, risk factor prevalence was low, although systolic blood pressure in women and rates of high triglycerides, impaired fasting glucose, hypertension, and the metabolic syndrome in men increased with increasing SAT tertile (all P < 0.04). In contrast, in the top VAT tertile, lower triglycerides were observed in men with increasing SAT (64.4% high triglycerides in SAT tertile 1 vs. 52.7% in SAT tertile 3, P = 0.03). Similar observations were made for women, although results were not statistically significant (50.6% high triglycerides in SAT tertile 1 vs. 41.0% in tertile 3, P = 0.10). Results in the highest VAT tertile were notable for a lack of increase in the prevalence of low HDL in men and women and in rates of impaired fasting glucose in men with increasing subcutaneous fat, despite sizable differences in BMI across SAT tertiles (27.1 to 36.3 kg/m²[women]; 28.1 to 35.7 kg/m²[men]).

CONCLUSIONS

Although adiposity increases the absolute risk of metabolic and cardiovascular disease, abdominal subcutaneous fat is not associated with a linear increase in the prevalence of all risk factors among the obese, most notably, high triglycerides.Obesity is associated with multiple cardiometabolic risk factors, including insulin resistance (1), diabetes (2), hypertension (3), and dyslipidemia (4). Variations in fat distribution may mediate such risks, with visceral adipose tissue (VAT) associated with more adverse risk factor profiles than abdominal subcutaneous adipose tissue (SAT) (5,6). The ectopic fat hypothesis proposes that obesity represents a failure of adipocyte growth and differentiation, resulting in “acquired lipodystrophy” and fat deposition in liver, skeletal muscle, and pancreatic β-cells (7). Such ectopic fat stores are hypothesized to contribute to the pathogenesis of impaired insulin secretion and insulin resistance and to mediate obesity-related cardiovascular disease (8).In addition to the detrimental effects of VAT, human and animal studies have suggested a possible protective role for subcutaneous fat. In humans, increased subcutaneous leg fat is associated with decreased risk of disturbed glucose metabolism and dyslipidemia, independent of abdominal fat (9). Thiazolidinedione treatment, which increases total fat mass, mostly in subcutaneous fat stores, improves insulin sensitivity (10). Removal of VAT by omentectomy results in decreased glucose and insulin levels in humans, (11), whereas removal of SAT by liposuction does not always result in improvements in glucose metabolism or lipid levels (12,13). Transplantation of subcutaneous fat into visceral compartments in mice produces decreases in body weight and total fat mass and improved glucose metabolism, suggesting that subcutaneous fat may be intrinsically different from visceral fat in ways that are beneficial (14).Therefore, the purpose of the present study was to test the hypothesis that abdominal subcutaneous fat is a protective fat depot in terms of cardiometabolic risk factor prevalence. We theorized that among those with similar levels of VAT, increasing SAT might be associated with decreases in cardiometabolic risk factor prevalence despite increasing BMI and total abdominal fat.     

Effects of weight loss on visceral and abdominal subcutaneous adipose tissue blood-flow and insulin-mediated glucose uptake in healthy obese subjects

Objective. Rapid weight loss with very-low-calorie diet (VLCD) is known to improve insulin sensitivity and decrease adipose tissue masses. The aim was to investigate the effects of VLCD on adipose tissue regional glucose uptake (rGU) and perfusion and their association with adipokines.

Research design and methods. Sixteen healthy obese (body mass index 33±1.1 kg/m²) subjects underwent VLCD for 6 weeks. RGU and perfusion were measured using [¹⁸F]-fluoro-deoxy-glucose, [¹⁵O]H₂O and positron emission tomography.

Results. Blood-flow and rGU expressed per gram of adipose tissue were higher in visceral fat compared to abdominal subcutaneous fat (P<0.01 for both). Dieting decreased weight by 11±0.9 kg (P<0.0001). Visceral adipose fat decreased by 25% (P<0.001) and abdominal subcutaneous fat by 16% (P<0.001). Whole body insulin sensitivity increased by 33% (P<0.01). Perfusion of both fat depots decreased (P<0.001), while rGU remained unchanged. Among the adipokines, leptin and interleukin-6 levels seemed to be associated with abdominal subcutaneous and intra-abdominal adipose tissue insulin resistance but not with adipose tissue perfusion.

Conclusions. Abdominal adipose tissue perfusion and rGU are not related in obesity. Rapid weight loss decreases perfusion through adipose tissue depots but has no influence on rGU demonstrating the ‘sink’ role of adipose tissue.     

Plasma apolipoprotein CI and CIII levels are associated with increased plasma triglyceride levels and decreased fat mass in men with the metabolic syndrome

OBJECTIVE—To determine whether, in accordance with observations in mouse models, high concentrations of the lipoprotein lipase inhibitors apolipoprotein (Apo) CI and ApoCIII are associated with increased triglyceride concentrations and decreased fat mass in men with the metabolic syndrome.RESEARCH DESIGN AND METHODS—Plasma ApoCI, ApoCIII, and triglyceride concentrations were measured in the postabsorptive state in 98 men with the metabolic syndrome. Subcutaneous and visceral fat areas were measured by 3T-magnetic resonance imaging.RESULTS—Triglyceride concentrations were 49% higher, and the average visceral fat area was 26% lower (both P < 0.001), in subjects with high ApoCI and ApoCIII compared with low ApoCI and ApoCIII. Subjects with either high ApoCI or ApoCIII had 16% (P < 0.05) and 18% (P < 0.01) decreased visceral fat area, respectively.CONCLUSIONS—High concentrations of ApoCI and ApoCIII are associated with increased triglycerides and decreased visceral fat mass in men with the metabolic syndrome. These findings translate mouse studies into human pathophysiology.Apolipoprotein (Apo) CI and ApoCIII are present on HDL and triglyceride (TG)-rich lipoproteins (1) and mainly affect plasma lipid metabolism by inhibition of lipoprotein lipase (LPL) (2). This enzyme hydrolyzes TG in VLDL and chylomicrons, releasing fatty acids for storage by adipocytes or for energy metabolism in muscles (2,3). Overexpression of human ApoCI in mice increases VLDL-associated TG plasma levels in combination with decreased body fat (4). The effect of ApoCIII overexpression is unknown, but ApoCIII deficiency in mice led to lower VLDL-associated TG levels and increased diet-induced obesity (5). Because it has recently been shown that LPL activity is higher in visceral adipose tissue (VAT) compared with subcutaneous adipose tissue (SAT) (6), LPL inhibitors such as ApoCI and ApoCIII may differentially affect VAT compared with SAT. The objective of this study was to determine whether, like in mouse models, high ApoCI and ApoCIII concentrations are associated with increased TG concentrations and decreased fat mass (VAT vs. SAT) in men with the metabolic syndrome.