Doctoral Dissertation Research: Thermogenesis and energetic costs in humans

这个博士论文项目将研究100名来自低纬度地区的成年人的棕色脂肪组织（BAT）的能量消耗，这是一种已知在寒冷条件下被激活的发热组织。成人对BAT的研究相对不足，本项目将扩大现有数据和地理范围，研究BAT在人体产热、能量分配和冷适应中的作用。该项目将促进人类生物学的基础知识，也可能为肥胖和糖尿病的公共卫生研究提供信息。除了直接向研究参与者传递一些数据外，项目成果还将通过社交媒体、公开演讲和开放获取期刊上的出版物等平台与更广泛的公众分享。此外，这项研究将促进与本地研究助理的研究合作，他们将发展STEM研究技能，并促进项目的顺利实施和文化上的适当。BAT已经在冬眠的哺乳动物和人类婴儿中进行了广泛的研究，但很少有研究关注它在成人中的功能。研究人员认为，BAT可能在人类进化中作为一种抵御慢性感冒的适应性防御机制发挥了作用，鉴于其对新陈代谢的生理作用，它也可能有助于降低代谢性疾病的风险。在这项研究中，BAT功能将在低纬度人群中进行检查，显示平均体型和形状，尽管生活在温暖地区，但在形态学上最适合保持热量。通过比较室温和轻度冷暴露下胸部和肩部（成人BAT的主要部位）的代谢率和散热来推断BAT。同时，将在BAT激活前后测量空腹血糖水平和呼吸商（决定代谢底物消耗的比率），以确定BAT对葡萄糖的利用。通过确定研究群体中BAT的代谢和产热能力，本研究将分析BAT如何可能是冷适应形态的生理反映，进而分析BAT如何在人类成功扩散到不同生态环境中发挥作用，而不依赖于其形态。更好地了解BAT的能量消耗和葡萄糖处理可以深入了解其在体重增加和糖尿病预防方面的潜在效用。BAT激活的这些潜在健康益处对于肥胖和糖尿病高发地区尤为重要。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This doctoral dissertation project will examine the energetic cost of brown adipose tissue (BAT), a heat-producing tissue known to be activated under cold conditions, in 100 adults from a lower-latitude population. Research on BAT in adults has been relatively understudied, and this project will expand the available data and geographic scope for investigating BAT’s role in human heat production, energy allocation, and cold adaptation. The project will advance fundamental knowledge in human biology, and may also inform public health research on obesity and diabetes. In addition to the direct transmission of some data to study participants, project outcomes will be shared with the greater public through platforms such as social media, public talks, and publications in open-access journals. Furthermore, this study will foster research collaborations with local research assistants, who will develop STEM research skills and facilitate the smooth and culturally appropriate implementation of the project. BAT has been extensively studied in hibernating mammals and in human infants, but fewer studies have focused on its functions in adults. Researchers have suggested that BAT may have played a role in human evolution as an adaptive defense mechanism against chronic cold and that it may also be useful in reducing risks of metabolic diseases given its physiological effects on metabolism. In this study, BAT function will be examined in a lower-latitude population showing an average body size and shape that is morphologically best adapted to retain heat despite living in a warm region. BAT will be inferred by comparing metabolic rates and heat dissipation in the chest and shoulder area (main BAT location in adults) at room temperature and at mild cold exposure. Simultaneously, fasting glucose levels as well as respiratory quotients (a ratio determining metabolic substrates consumed) will be measured before and after BAT activation to determine BAT’s use of glucose. By determining the metabolic and heat-producing capabilities of BAT in the study population, this research will parse out how BAT may be a physiological reflection of cold adapted morphology and by extension how BAT may have played a role in the successful dispersal of humans into different ecological settings independent of their morphology. A better understanding of the energy consumption and glucose disposal of BAT can provide insight into its potential utility in weight gain and diabetes prevention. These potential health benefits of BAT activation are especially important for regions burdened by high rates of obesity and diabetes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.