Functional Brain Imaging and Appetite-Related Hormones Pre and Post Obesity Surge

摘要：这是一项采用功能性磁共振成像(FMRI)和食欲相关测量的研究。 减肥手术前后的激素浓度。食物摄入量减少的机制和 肥胖症手术后的体重减轻还不是很清楚。参与者将在手术前和3个月内接受研究 世界上最常见的两种手术：腹腔镜胃分流术(RYGB)和 腹腔镜可调胃束带术(GB)。这两个手术组将与两个对照组进行比较 分组：1)通过配方饮食(WL)进行为期3个月的主动减肥；2)接受手术治疗的患者 手术或不治疗(NT)。功能磁共振成像将被用来检查大脑激活的区域，以响应视觉和 可口的高能量食物、不太可口的低能量食物和非食物的听觉刺激。在3个月，相对的 为了研究基线，预计大脑关键区域的激活会减少，比如前额叶 大脑皮层，对RYGB后高能食物刺激的反应。相比之下，应该增加 GB后这些区域的激活，WL的激活程度更大，NT无变化。会有一些 大脑活动在18个月前恢复到基线水平，特别是在体重恢复的情况下，WL的大脑活动没有变化 新界别。这两种手术都限制了胃的大小，但RYGB比GB和 包括切开胃部并绕过一段肠子。胃的切开可以 导致促食欲激素Ghrelin水平降低，Ghrelin主要由胃产生，并与 肠道转流，以提高餐后厌食激素、PYY和GLP-1的水平。荷尔蒙将会 在三个时间点中的每一个时间点测量固定流质餐前后的数据。预计GB和到A 在更大程度上，WL将在3个月时经历与RYGB相反的这些激素的变化 相对于研究基线，有些人在18个月回到这个基线。作为次要目标，我们将评估饮食 疾病，重点是暴饮暴食障碍(Bed)，预计在RYGB之后下降最大，但开始 要在18点返回。术前进食障碍，特别是卧床，及其术后的变化 检查并与大脑激活、胃肠激素和体重减轻的变化有关。我们将相对招收128人 健康(非糖尿病)临床重度肥胖男性和女性，BMI为40-50，32 RYGB，32 GB，32 WL， 和32个碱基。体重指数范围将确保几乎所有的S？S都能装进扫描仪。所有四个小组都将被匹配 体重指数和男女比例约为3：1，以及种族。这些发现应该会改善我们的 了解减肥手术后促进食欲和减轻体重的生物学机制。 这可能会导致外科手术程序的改进，并对导致 肥胖，这可能为新的侵入性较小的治疗方法提供基础。

Abstract: This is a study employing functional magnetic resonance imaging (fMRI) and measures of appetiterelated hormone concentrations pre and post bariatric surgery. The mechanisms of reduced food intake and weight loss after obesity surgery are not well understood. Participants will be studied prior to surgery as well as 3 mo and 18 mo following the two most common operations world wide: laparoscopic gastric bypass (RYGB) and laparoscopic adjustable gastric banding (GB). These two operative groups will be compared to two control groups: 1) active weight loss on a formula diet (WL) for 3 mo; and 2) candidates for surgery who do not have an operation, or no treatment (NT). fMRI will be used to examine areas of brain activation in response to visual and auditory stimuli of palatable high energy foods, less palatable low energy foods, and non foods. At 3 mo, relative to study baseline, it is expected that there will be reduced activation in key brain areas, such as the prefrontal cortex, in response to the high-energy food stimuli after RYGB. In contrast, there should be an increase in activation in these areas after GB and to an even greater extent in WL and no change in NT. There will be some return in brain activation to baseline by 18 mo, especially for WL with expected weight regain, and no changes in NT. Both surgical operations restrict the size of the stomach, but RYGB is much more invasive than GB and involves sectioning the stomach and bypassing a segment of the intestine. The sectioning of the stomach may lead to lower levels of the orexigenic hormone, ghrelin, produced mainly by the stomach, and combined with the intestinal bypass, to higher post meal levels of the anorexigenic hormones, PYY and GLP-1. Hormones will be measured prior to and after a fixed liquid meal at each of the three time points. It is expected that GB, and to a greater extent WL, will experience changes in these hormones in the opposite direction from RYGB at 3 mo relative to study baseline, with some return to this baseline at 18 mo. As a secondary aim, we will assess eating disorders, focusing on binge eating disorder (BED), which are expected to decline the most after RYGB but to start to return at 18 mo. Presurgery eating disorders, particularly BED, and their changes post surgery will be examined and related to changes in brain activation, gut hormones, and weight loss. We will enroll 128 relatively healthy (nondiabetic) clinically severe obese men and women with a BMI of 40-50, with 32 RYGB, 32 GB, 32 WL, and 32 NT. The BMI range will ensure that virtually all S¿s will fit into the scanner. All four groups will be matched for BMI and for female to male ratio of about 3 to1, as well as for race. The findings should improve our knowledge of the biological mechanisms that contribute to appetite and weight reduction after bariatric surgery. This may lead to improvements in the surgical procedures and to new insights into basic mechanisms that lead to obesity, which could provide the basis for new less invasive treatments.