Metabolic Research Core: energy balance and obesity studies

我们发现我们的全房间间接量热套件(2008年8月投入使用)存在系统性问题。在今年冬天，我们在所有三个房间都检测到了显著的文物，导致性能不稳定。经过严格的测试，我们追踪到这个问题是由于建筑送风的相对湿度极低，因为它在燃烧室和参考空气之间引入了(水蒸气的)高分压。我们与建筑工程师和设施管理办公室、研究设施办公室和临床中心的官员进行了接触。我们确认了我们发现的低湿度，目前正在努力采取三管齐下的方法来纠正这个问题：(1)加强新陈代谢单元送风的湿度控制，以便为OFM提供更稳定的环境；(2)使用临床中心的医疗空气作为量热室的送风；以及(3)改造量热空气样品和空调设备、校准气体混合和分析仪升级。在NIDDK领导层和临床中心的大力支持下，我们正在稳步推进这些关键的翻修工作。 研究结果：在25名年轻和体重正常的健康志愿者中，Celi博士和他的同事们发现，按照我们的代谢套件衡量，12小时的环境温度变化(从24摄氏度到19摄氏度)会导致静息能量消耗增加6%。这种增加可能是通过交感神经系统激活棕色脂肪组织的结果，但受甲状腺激素的影响较小。虽然正在进行更多的研究，以研究肥胖和老年人，并通过FDG-PET成像进一步量化棕色脂肪组织的活动，但我们已经发表了目前的发现。 我们正在继续我们与Vanderbilt大学的Naji Abumrad博士的壁内外合作项目，研究Roux-en-Y胃旁路手术前后能量代谢、蛋白质周转、胰岛素作用和相关体重减轻的变化。Vanderbilt的研究已经停止了新的招募，但我们跟踪了我们研究的患者在快速减肥期间的全身代谢。我们最近在《肥胖》杂志上发表了一篇手稿。 提供的服务(2009财年活动)：全室呼吸室24小时能量消耗(299)，代谢车静息能量消耗(364)，运动和身体功能测试(144)，身体成分(581 Bod测量，388次iDXA扫描)，客观体力活动监测(588)，食物排列实验用餐(146)，肌肉活组织检查(28)，皮下脂肪活检(79)，以及健康和身体检查(75)。尽管代谢室存在湿度问题，但所有活动都比08财年显著增加。

We discovered a systemic problem with our whole-room indirect calorimetry suites (commissioned in August 2008). During the winter of this year, we detected significant artifacts in all three chambers that lead to unstable performances. After rigorous testing, we traced the issue to extreme low relative humidity of the building supply air as it introduced high differential partial pressure (of water vapor) between the chamber and reference air. We engaged with building engineers and officials from Office of Facility Management, Office of Research Facilities, and the Clinical Center. We confirmed our findings of low humidity and are currently working towards a three-prong approach to rectify the issue: (1) tighter humidity control of the Metabolic Unit supply air to provide a more stable environment by the OFM, (2) use the Clinical Center medical air as supply air for the calorimetry suites, and (3) revamp the calorimetry air sample and condition equipment, calibration gas mixing, and analyzer upgrades. With the strong support from NIDDK leadership and Clinical Center, we are making steady progress in these critical renovations. Research findings: In 25 young and normal-weight healthy volunteers, Dr. Celi and his colleagues have found that a 12-hr environmental temperature change (from 24 to 19 C) produced a 6% increase in resting energy expenditure as measured by our metabolic suites. This increase was likely a result of the activation of brown adipose tissue via the sympathetic nervous system, but less of an influence by the thyroid hormone. While expanded studies are underway to study obese and elderly individuals and to further quantify the brown adipose tissue activity by FDG-PET imaging, we have published the current findings. We are continuing our intra/extramural collaboration project with Dr. Naji Abumrad from Vanderbilt University to study the changes in energy metabolism, protein turnover, insulin action, and associated weight loss before and after Roux-en-Y gastric bypass surgery. The Vanderbilt study has stopped new recruitment but we following up the patients that we studied on whole-body metabolism during rapid weight loss. We have published a manuscript in Obesity recently. Services rendered (FY09 activities): 24-hr energy expenditure by whole-room respiratory chambers (299), resting energy expenditure by metabolic carts (364), exercise and physical function testing (144), body composition (581 Bod Pod measurements, 388 iDXA scans), objective physical activity monitoring (588), food-array experimental dinning (146), muscle biopsies (28), subcutaneous fat biopsies (79), and Health and Physical Exams (75). All activities are significantly up from FY08, despite of the humidity issue with the metabolic chambers.