Aerobic exercise training reduces epicardial fat in obese men

The purpose of this study was to determine the effects of exercise training on ventricular epicardial fat thickness in obese men and to investigate the relationship of the change in epicardial fat thickness to changes in abdominal fat tissue following exercise training. Twenty-four obese middle-aged men [age, 49.4 +/- 9.6 yr; weight, 87.7 +/- 11.2 kg; body mass index (BMI), 30.7 +/- 3.3 kg/m(2); peak oxygen consumption, 28.4 +/- 7.2 ml.kg(-1).min(-1); means +/- SD] participated in this study. Each participant completed a 12-wk supervised exercise training program (60-70% of the maximal heart rate; 60 min/day, 3 days/wk) and underwent a transthoracic echocardiography. The epicardial fat thickness on the free wall of the right ventricle was measured from both parasternal long- and short-axis views. The visceral adipose tissue (VAT) and subcutaneous adipose tissues were measured by computed tomography. Following exercise training, the epicardial fat thickness was significantly decreased (P < 0.001). The percentage change of epicardial fat thickness was twice as high compared with those of waist, BMI, and body weight of original values (P <0.05). There was a significant relationship (r = 0.525, P = 0.008) between changes in the epicardial fat thickness and VAT with exercise training. Stepwise multiple regression analysis revealed that the change in VAT, change in systolic blood pressure, and change in quantitative insulin sensitivity check index were independently related to the change epicardial fat thickness (P < 0.05). The ventricular epicardial fat thickness is reduced significantly after aerobic exercise training and is associated with a decrease in VAT. These results suggest that aerobic exercise training may be an effective nonpharmacological strategy for decreasing the ventricular epicardial fat thickness and visceral fat area in obese middle-aged men.     

Self-efficacy and dietary fat reduction behaviors in obese African-American and white mothers

This study examined the influence of weight management and education on five types of fat reduction behaviors mediated through three task-specific domains of self-efficacy among young, low-income obese African-American and white mothers. It also investigated interaction of race with the relationships between weight management, education, self-efficacy, and fat reduction behaviors. A sample of obese African-American and white mothers was recruited from the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Wisconsin. Participants reported their weight management status, education, self-efficacy for eating low-fat food, and fat reduction behaviors. For both racial groups, weight management status predicted low-fat food substitution and meat modification behaviors; education predicted meat modification behavior. Three task-specific domains of self-efficacy (negative mood, positive mood, and food availability) predicted different types of fat reduction behaviors and differed by race. Weight management influenced behaviors of low-fat food substitution, meat modification, and fried-food avoidance, mediated partially through self-efficacies of negative mood (African Americans), positive mood (African Americans, whites), and food availability (African Americans). Race affected the relationships between weight management, education, three task-specific domains of self-efficacy, and five types of fat reduction behaviors. Self-efficacies operated differentially for African Americans and whites. Thus, strategies to address specific fat reduction behaviors have the potential to be more effective when tailored to specific individual characteristics such as racial background, history of weight management strategies and task-specific domains of self-efficacy.     

Predictors of ectopic fat accumulation in liver and pancreas in obese men and women

The aim of the present study was to determine the relationship between body fat distribution, adipocytokines, inflammatory markers, fat intake and ectopic fat content of liver and pancreas in obese men and women. A total of 12 lean subjects (mean age 47.25 ± 14.88 years and mean BMI 22.85 ± 2), 38 obese subjects (18 men and 20 women) with mean age 49.1 ± 13.0 years and mean BMI 34.96 ± 4.21 kg/m2 were studied. Measurements: weight, height, BMI, waist circumference, as well as glucose, insulin, HOMA (homeostasis model assessment of insulin resistance), cholesterol, triglycerides, high-density lipoprotein cholesterol, high sensitivity C-reactive protein, daily energy intake, leptin, and adiponectin. Magnetic resonance was used to evaluate visceral, subcutaneous adipose tissue (SCAT) as well as liver and pancreas lipid content using in-phase and out-of-phase magnetic resonance imaging (MRI) sequence. Obese subjects had significantly higher weight, waist circumference, SCAT, deep SCAT, visceral adipose tissue (VAT), liver and pancreatic lipid content than lean subjects. Obese women had significantly lower VAT, liver and pancreas lipid content regardless of same BMI. In multiple regression analyses, the variance of liver lipid content explained by gender and VAT was 46%. When HOMA was added into a multiple regression, a small increase in the proportion of variance explained was observed. A 59.2% of the variance of pancreas lipid content was explained by gender and VAT. In conclusion, obese men show higher VAT and ectopic fat deposition in liver and pancreas than obese women despite same BMI. Independent of overall adiposity, insulin resistance, adiponectin and fat intake, VAT, measured with MRI, is the main predictor of ectopic fat deposition in both liver and pancreas.     

Increasing dietary fat elicits similar changes in fat oxidation and markers of muscle oxidative capacity in lean and obese humans

In lean humans, increasing dietary fat intake causes an increase in whole-body fat oxidation and changes in genes that regulate fat oxidation in skeletal muscle, but whether this occurs in obese humans is not known. We compared changes in whole-body fat oxidation and markers of muscle oxidative capacity differ in lean (LN) and obese (OB) adults exposed to a 2-day high-fat (HF) diet. Ten LN (BMI = 22.5±2.5 kg/m², age = 30±8 yrs) and nine OB (BMI = 35.9±4.93 kg/m², 38±5 yrs, Mean±SD) were studied in a room calorimeter for 24hr while consuming isocaloric low-fat (LF, 20% of energy) and HF (50% of energy) diets. A muscle biopsy was obtained the next morning following an overnight fast. 24h respiratory quotient (RQ) did not significantly differ between groups (LN: 0.91±0.01; OB: 0.92±0.01) during LF, and similarly decreased during HF in LN (0.86±0.01) and OB (0.85±0.01). The expression of pyruvate dehydrogenase kinase 4 (PDK4) and the fatty acid transporter CD36 increased in both LN and OB during HF. No other changes in mRNA or protein were observed. However, in both LN and OB, the amounts of acetylated peroxisome proliferator-activated receptor γ coactivator-1-α (PGC1-α) significantly decreased and phosphorylated 5-AMP-activated protein kinase (AMPK) significantly increased. In response to an isoenergetic increase in dietary fat, whole-body fat oxidation similarly increases in LN and OB, in association with a shift towards oxidative metabolism in skeletal muscle, suggesting that the ability to adapt to an acute increase in dietary fat is not impaired in obesity.     

Regional lung strain in dogs during deflation from total lung capacity

Regional lung distortion during deflation from total lung capacity to functional residual capacity (FRC) in intact supine and prone anesthetized dogs was determined from the displacement of multiple metallic markers embedded in the lung parenchyma. Distortion was expressed as strain (epsilon), which is related to fractional length changes. In the supine position, transverse strain (epsilon yy) was larger than vertical strain (epsilon xx) and cephalocaudal strain (epsilon zz) in the upper lobe. The FRC of the lower lobe was smaller than FRC of the upper lobe and all strains were larger, but epsilon zz increased most and became equal to epsilon yy. In the prone position, epsilon yy was largest in all upper lobes and in three of four lower lobes. Strains and volumes of the upper and lower lobes were similar. The upper and lower lobes rotated slightly around different axes, indicating that interpleural fissures allow additional degrees of freedom for the lungs to conform to the thoracic cavity. In the prone position, there were no consistent gradients of strain or volume. These results indicate that, in determining the regional distribution of FRC in the recumbent dog, in addition to the effect of gravity on the lung, there are important interactions between lung and thoracic cavity shapes.     

经纤支镜国产气道覆膜支架肺减容术治疗肺气肿模型的应用研究

目的:研究经纤支镜国产气道覆膜支架肺减容术治疗肺气肿动物模型的可行性、治疗效果及并发症发生情况。方法:4只雌性山羊应用局部气管内滴注木瓜蛋白酶方法复制不均一肺气肿模型。经电子支气管镜通过推送装置在肺气肿模型的不同支气管亚段(右肺上叶前段或后段)放入1-2枚气道覆膜支架,术前1天及术后6周测肺功能、查血气分析及胸部CT扫描。观察有无肺部感染等并发症。结果:支架植入后6周发现肺总量(TLC)、功能残气量(FRC)、残气量(RV)均出现下降,与术前比较均有统计学意义(p0.05)。RV/TLC(%)从术前的42.55%降至20.37%。PaO2从(70.50±1.85)mmHg上升至(81.25±1.11)mmHg,有统计学意义(p0.05)。CT检查及肺组织大体标本证实支架远端存在肺不张。仅有一只出现肺部感染早期症状,全部动物未发生气胸、肺脓肿等严重并发症。结论:经纤维支气管镜植入国产气道覆膜支架行肺减容术治疗肺气肿具有治疗效果确切、创伤小、安全性好、操作方便等特点。     

经支气管镜肺减容术治疗肺气肿的研究进展

外科肺减容术(LVRS)已经显示,在对筛选的不均一性肺气肿病人的治疗中,可改善病人的呼吸功能、运动能力和呼吸困难症状.然而肺减容术作为外科治疗,存在着潜在的死亡率和发病率,因而出现了无须开胸、创伤性小的经支气管镜肺减容术(BLVR)治疗.目前的研究主要包括:1.使用单向活瓣促使靶段肺萎陷,2.向靶段肺内注入封堵液,以促其肺不张并纤维化,3.通过支气管开窗术以增加呼出气量.其目的都是获得LVRS益处,而减少LVRS的手术创伤及风险.尽管目前还缺少大规模的随机对照临床试验结果,但BLVR治疗已展现了巨大的临床应用前景,将为治疗肺气肿提供更多的选择.