Maintaining thermogenesis during cold exposure in humans: relying on multiple pathways

在人类寒冷暴露期间维持产热：依赖多种途径

• 批准号: RGPIN-2016-05291
• 负责人: Haman, François
• 金额: $ 2.04万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709140
• 关键词: Maintaining; thermogenesis; during; cold; exposure

Through evolution, humans have acquired efficient metabolic and physiological defenses to dissipate heat in warm climates. However, their furless bodies do little to prevent excessive heat loss in cold environments. In the cold, humans must rely on the concerted activation of physiological processes that increase Hprod and lower heat loss (Hloss). When exercise is not possible, the increase in Hprod is achieved involuntarily by the activation of ST and to a lesser extent by NST. By combining metabolic, isotopic, biochemical and electrophysiological approaches, the long-term objective of the proposed research program is to better understand the mechanisms that regulate and maintain thermogenenic processes in humans exposed to adverse environments. Currently, it focuses on three main areas of research: 1) Effects of cold acclimation on thermogenic processes, 2) The partitioning of energy reserves for sustaining thermogenic processes during acute cold exposure, 3) The metabolic and neuromuscular principles that govern muscle activity in the cold. These overall questions constitute the continuation of previous experiments conducted for the last 10 y in my laboratory. They will advance the current knowledge by focusing on long duration acute cold exposure in non cold acclimatized subjects and on the effects of various cold acclimation levels of thermogenic processes. Building on our previous studies, the proposed work will quantify: 1) the effects of intense cold acclimation on the respective contributions of ST and NST to Hprod, 2) the changes in plasma glucose, muscle glycogen, CHO, lipid and protein oxidation during long duration cold exposure, 3) the effects of long duration cold exposure and cold acclimation on ST pattern. Building on the knowledge gained in the last ten years of NSERC funding, the proposed experiments will include the combination indirect calorimetry, whole body metabolic tracer and electromyographic methodologies developed in the applicant laboratory. However, to better understand the metabolic requirements of individual tissues in cold exposed adult humans and the metabolic requirements of shivering muscles. These combined techniques will allow the applicant and his trainees to establish more clearly the factors that modulate the relative use of metabolic fuels and the relative contribution of ST and NST. Results from this research program, together with the novel experimental approach, will expand on previous work funded by NSERC and provide novel information for shivering research. It will help achieve the long term objective of improving the characterization of the metabolic basis of shivering in humans.

通过进化，人类获得了有效的新陈代谢和生理防御系统，以在温暖的气候中散热。然而，它们没有皮毛的身体在寒冷的环境中几乎没有防止过多的热量损失。在寒冷中，人类必须依赖于生理过程的协同激活，从而增加Hprod和降低热量损失(HLOSS)。当运动不可能时，Hprod的增加是通过ST的非自愿激活实现的，在较小程度上是由NST实现的。通过结合代谢、同位素、生化和电生理方法，拟议研究计划的长期目标是更好地了解暴露在不利环境中的人类产热过程的调节和维持机制。目前主要集中在三个方面的研究：1)冷习服对生热过程的影响，2)在急性冷暴露期间维持生热过程的能量储备的分配，3)在寒冷中支配肌肉活动的代谢和神经肌肉原理。这些全面的问题构成了过去10年在我的实验室进行的实验的继续。他们将通过关注非冷习服受试者的长期急性冷暴露以及不同程度的冷习服对产热过程的影响来推进当前的知识。在我们以往研究的基础上，本工作将量化：1)高强度冷习服对ST和NST对Hprod的贡献的影响；2)长时间冷暴露对血糖、肌糖原、CHO、脂肪和蛋白质氧化的影响；3)长时间冷暴露和冷习服对ST模式的影响。 在NSERC资助的最后十年中获得的知识的基础上，拟议的实验将包括在申请实验室开发的间接量热法、全身代谢示踪剂和肌电方法的组合。然而，为了更好地了解寒冷暴露的成年人个体组织的代谢需求，以及颤抖肌肉的代谢需求。这些综合技术将使申请者和他的受训人员能够更清楚地确定调节代谢性燃料的相对使用以及ST和NST的相对贡献的因素。这一研究项目的结果，以及新的实验方法，将在NSERC资助的先前工作的基础上进行扩展，并为颤抖研究提供新的信息。它将有助于实现改善人类颤抖代谢基础的特征的长期目标。