ORGAN MASS & TISSUE METABOLIC RATES ACROSS AGE & RACE

器官质量

• 批准号: 6577748
• 负责人: DYMPNA GALLAGHER
• 金额: $ 14.86万
• 依托单位: ST. LUKE'S-ROOSEVELT INST FOR HLTH SCIS
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6577748
• 关键词: African American; adipose tissue; age difference; basal metabolism; blood chemistry; body composition; brain; caucasian American; clinical research; functional ability; gender difference; heart dimension /size; human old age (65+); human subject; kidney; liver; magnetic resonance imaging; organ; oxygen consumption; photon absorptiometry; positron emission tomography; racial /ethnic difference; striated muscles; tissues; young adult human (21-34)

Despite numerous attempts to explain the decrease in resting energy expenditure (REE) with age, and substantial variations in REE that occur between races, the mechanisms involved remain elusive. The loss of fat fee mass (FFM) cannot fully explain the decrease in RE in elderly. Since the FFM compartment consists of numerous tissues and organs, each with a different oxidative metabolic capacity, the possibility exists that changes in the proportion of these tissues with age may explain the lower REE in elderly. Moreover, REE is lower in African-American (AA) compared to Caucasian (C) metabolism at the organ/tissue level using non-invasive techniques are limited. Magnetic resonance imaging (MRI) allows for the complete reconstruction of organ and tissue volumes in vivo in combination with gated cardiac MRI. Project 4 aims are to test whether: 1) a portion of age-related changes in REE are explainable by changes in the relative fractions of high (brain, heart, liver, kidney) and low (skeletal, muscle, adipose tissue) metabolic activity tissues with respect to oxidative metabolism, 2) the cell mass fraction of skeletal muscle is reduced in elderly compared to young women and using a regional K+ counter and MRI, 3) a portion of age-related changes in REE can be explained by reductions in the metabolic activity of brain and myocardial tissues using positron emission tomography (PET) for the in vivo quantification of labeled 150 uptake, 4) there is a non-significant contribution of race to REE after appropriately measuring specific metabolically active compartments (liver, brain, kidneys, heart, skeletal muscle, adipose tissue) in AA and C adults. One hundred and sixty (20- 80 years) AA and C, healthy men and women will be measured, equally distributed to produce a 2 X 2 factorial design. A subset (n=70) of subjects will undergo additional dynamic PET studies combined with 15/O steady-state inhalation techniques to quantify brain and myocardial oxygen consumption. The proposed studies promise to anser important body composition related questions regarding the genesis of age and race differences in REE and other significant biological information.

尽管人们多次尝试解释静息能量消耗 (REE) 随着年龄的增长而减少，以及种族之间 REE 的巨大差异，但所涉及的机制仍然难以捉摸。脂肪质量（FFM）的减少并不能完全解释老年人RE的减少。由于 FFM 区室由众多组织和器官组成，每个组织和器官具有不同的氧化代谢能力，因此这些组织的比例随年龄的变化可能可以解释老年人中 REE 较低的原因。此外，与白种人 (C) 相比，非洲裔美国人 (AA) 的 REE 含量较低，但使用非侵入性技术在器官/组织水平上的代谢受到限制。磁共振成像 (MRI) 与门控心脏 MRI 相结合，可以完整重建体内器官和组织体积。项目 4 的目的是测试：1) REE 中与年龄相关的部分变化是否可以通过高代谢活动（大脑、心脏、肝脏、肾脏）和低代谢活动（骨骼、肌肉、脂肪组织）相对分数的变化来解释与氧化代谢相关的组织，2) 与年轻女性相比，老年人骨骼肌的细胞质量分数降低，并使用区域 K+ 计数器和 MRI，3) REE 中与年龄相关的部分变化可以解释为使用正电子发射断层扫描 (PET) 对标记 150 摄取进行体内定量，从而减少大脑和心肌组织的代谢活动，4) 在适当测量特定代谢活性区（肝脏、肝脏、 AA 和 C 成人的大脑、肾脏、心脏、骨骼肌、脂肪组织）。将测量 160 名（20-80 岁）AA 和 C 健康男性和女性，平均分配以生成 2 X 2 因子设计。一部分受试者 (n=70) 将接受额外的动态 PET 研究并结合 15/O 稳态吸入技术来量化大脑和心肌的耗氧量。拟议的研究有望回答有关 REE 年龄和种族差异的起源以及其他重要生物信息的重要身体成分相关问题。