Human Energy and Body Weight Regulation Core

研究重点： 1. 棕色脂肪组织作为一种潜在的增加能量消耗的来源继续引起我们的兴趣。在与Celi博士的合作中，我们刚刚完成了对31名健康志愿者在代谢室中进行的两项过夜研究，12小时的环境温度随机分为24或19 ℃。我们发现，在19摄氏度与24摄氏度的情况下，12小时的能量消耗增加了5-6%，这与我们之前发表的白天发现相当。为了探索棕色脂肪组织的作用，我们通过18FDG-PET成像测量其活性。虽然只有6名受试者在19 ℃时显示出可见的棕色脂肪组织活动（与25 ℃时无活动相比），但我们假设全身FDG摄取水平可以计算出来，为我们提供用于产热的整体燃料利用率的度量，从而更好地与能量消耗的个体变化相关。我们正在分析这些数据并准备手稿。 2. 在减肥过程中，除无脂肪质量和脂肪质量的损失外，静息能量消耗也可能减少。在与Simchowitz和Celi博士的合作中，我们正在研究甲状腺激素在减肥过程中对静息能量消耗变化的潜在作用，使用静息能量消耗，身体成分，和甲状腺激素水平在基线和整个体重减轻在一组（n=36）通过生活方式干预进行体重减轻的患者中，进行频繁随访和重复测量。初步分析显示，在控制脂肪和无脂肪质量变化后，T3水平的变化趋势和早期减肥阶段（1个月和3个月）静息能量消耗的变化趋势，但6个月后未观察到相关性。 3. 黑人女性超重的患病率高于白色女性，并且与胰岛素介导的葡萄糖摄取的更大损害相关。运动表现，影响胰岛素敏感性，有助于葡萄糖利用的种族差异正在探索在153名非糖尿病超重妇女（63%黑人）的患者队列中，由Cannon博士和我们的小组（与Sumner博士）。我们发现黑人的运动能力和胰岛素敏感性指数（通过IVGTT测量）之间存在统计学显著相关性，但白人没有。我们继续分析这些数据并准备手稿。 4. 较低的核心体温“设定点”被认为是可能使人类容易患肥胖症的一个因素。与Yanovski和Skarulis博士一起，我们测试了肥胖个体的核心温度可能低于正常体重个体的假设。然而，我们没有发现46名肥胖和35名非肥胖健康志愿者（在代谢单位研究）的平均每日或24小时核心温度曲线存在差异。我们确实发现女性的平均核心温度比男性高0.23摄氏度，这与之前的其他研究相似。这项研究发表在AJCN上。 提供服务（FY 11活动）：全室呼吸室24小时能量消耗（244），代谢推车静息能量消耗（371），运动和身体功能测试（86），实验性饱腹感测试（139），身体成分（404 Bod Pod，390 DXA），客观体力活动监测（467天），肌肉活检（23），皮下脂肪活检（88），健康和身体检查（50）。

Research highlights: 1. Brown adipose tissue continues to interest us as a potential source of increasing energy expenditure non-pharmacologically. In collaboration with Dr. Celi, we just completed studying 31 healthy volunteers in two overnight studies in the metabolic chamber, 12-hr environmental temperature randomized at 24 or 19 C. We found a 5-6% increase in 12-hr energy expenditure at 19 vs. 24 C which is comparable to our previously published finding in the day time. In order to explore the role of the brown adipose tissue we measured its activity by 18FDG-PET imaging. Although only 6 subjects showed visible brown adipose tissue activity at 19 C (as compare to none at 25 C), we hypothesis that the whole-body FDG uptake levels might be calculated to give us a metric of overall fuel utilization for heat generation, and thus better correlate with the individual changes in energy expenditure. We are in the process of analyzing this data and preparing a manuscript. 2. Resting energy expenditure may be reduced during weight loss in additional to the loss of fat-free mass and fat mass. In collaboration with Drs. Simchowitz and Celi, we are studying the potential role of thyroid hormone in contributing to the changes in resting energy expenditure during weight loss, using the repeated measurements of resting energy expenditure, body composition, and thyroid hormone levels at baseline and throughout the weight loss (up-to one year) in a group of (n=36) patients who are going through weight loss by life-style interventions with frequent follow-ups and repeated measurements. Preliminary analysis has shown trends in the changes in T3 levels and changes in resting energy expenditure in the early weight loss stage (one and three months), after controlling for the changes in fat and fat-free masses, but the association was not seen after 6 months. 3. The prevalence of overweight black women is higher than that of white women, and is associated with greater impairment in insulin-mediated glucose uptake. Exercise performance, which affects insulin sensitivity, contributes to a race difference in glucose utilization is being explored in 153 non-diabetic overweight women (63% black) in a cohort of patients by Dr. Cannon and our group (with Dr. Sumner). We found a statistical significant association between exercise capacity and insulin sensitivity index (as measured by IVGTT) in blacks but not in whites. We continue to analyze this data and to prepare the manuscript. 4. A lower core body temperature "set point" has been suggested to be a factor that could potentially predispose humans to develop obesity. Together with Drs. Yanovski and Skarulis, we tested the hypothesis that obese individuals might have lower core temperatures than those in normal-weight individuals. We did not, however, find a difference in mean daily or 24-hr time profiles of core temperature between 46 obese and 35 non-obese healthy volunteers (studied on the metabolic unit). We did find women to have a 0.23 C greater mean core temperature than men, which was similar to other previous studies. This study was published in AJCN. Services rendered (FY11 activities): 24-hr energy expenditure by whole-room respiratory chambers (244), resting energy expenditure by metabolic carts (371), exercise and physical function testing (86), experimental satiety test (139), body composition (404 Bod Pod, 390 DXA), objective physical activity monitoring (467 days), muscle biopsies (23), subcutaneous fat biopsies (88), and Health and Physical Exams (50).