Muscle quality, exercise and weight loss in older women: A quantitative MRI stud

老年女性的肌肉质量、锻炼和减肥：定量 MRI 研究

基本信息

批准号：
7677986
负责人：
JOHN G GEORGIADIS
金额：
$ 22.02万
依托单位：
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-09-01 至 2011-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7677986
关键词：
Address Adipose tissue Aging Area Body Composition Body Weight Body Weight decreased Caloric Restriction Clinical Diet Disease Elderly Elderly woman Emulsions Exercise Fatty acid glycerol esters Female Goals Imaging technology Independent Living Insulin Insulin Resistance Intervention Intramuscular Link Lipids Longitudinal Studies Lower Extremity Magnetic Resonance Imaging Measures Medical Imaging Metabolic Muscle Non obese OGTT Obesity Outcome Performance Physical Fitness Physical Function Physical activity Physiological Play Protons Public Health Quality of life Randomized Recruitment Activity Relative (related person)Research Research Design Risk Role Simulate Skeletal Muscle Spatial Distribution Spectrum Analysis Structure Thigh structure Training Translational Research Translations Treatment Protocols Triglycerides Tubular formation Upper arm Weight Woman clinically relevant cohort density design disability fitness functional outcomes imaging modality improved in vivo male meetings muscle form muscle strength muscular structure novel nutrition older women programs sedentary

项目摘要

DESCRIPTION (provided by applicant): The overarching goal of this three year project is to develop and validate novel medical imaging methods to address the problem of obesity in elderly females. Aging and physical inactivity are associated with changes in body composition characterized by increases in fat mass and reductions in fat-free mass. Muscle-associated lipids, specifically intramuscular triglycerides (IMTG) may play larger role than appreciated with regard to muscle quality. Weight loss and exercise regimens effects on IMTG may alter myofiber orientation and density, and subsequently alter the effective muscle physiological cross-sectional area (PCSA) which is proportional to the maximum muscle force. The specific aims of the proposed research are: (1) to establish the precision and sensitivity of Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) to quantify IMTG and histoarchitecture, defined as muscle quality, (2) to explore the relation of these muscle attributes to insulin action and muscle strength and physical function in elderly women differing in adiposity and habitual physical activity, and (3) after exercise training and weight loss. The first aim will be met by employing a sophisticated phantom mimicking the hierarchical structure of the muscle. Towards aim (2-3), fifty elderly (65 80 y) females will be recruited and blocked on adiposity (normal weight vs. obese), and normal weight women will be further blocked on physical fitness (sedentary vs. physically active) and will be assessed for muscle associated lipids and histoarchitecture using a cross-sectional design. A parallel- arm study design will also be used with the obese women randomized to either a weight loss program induced by caloric restriction alone to elicit a reduction of 10% body weight or a weight stable exercise program for 6 months to explore the sensitivity of the MRI and MRS measures to histochemically known perturbations of muscle quality. It is anticipated that exercise will impact muscle quality more than body fatness (cross-sectional design) or weight loss (longitudinal study). Moreover, because lipids contained within or near muscle are speculated to reduce muscle quality both from a fuel and muscle strength perspective, quantitative measures of muscle quality afforded by MRI and MRS will be related to clinical measures of insulin resistance and muscle strength and performance. The further refinement and application of proton MRI and MRS to quantify IMTG impacts on muscle quality will aid the ultimate clinical translation of this project which is to elucidate mechanisms whereby weight loss or exercise improves muscle quality in obese women at risk for disability due to disordered body composition. Obesity in the elderly is linked to disability, reductions in independent living and quality of life. Lipids contained within or near muscle are speculated to reduce muscle quality both from a fuel and muscle strength perspective. Noninvasive and accurate medical imaging technologies (MRI) will be used to link the effect of nutrition and exercise on the structure and function of the thigh muscle in obese women at risk for disability due to disordered body composition.

描述（由申请人提供）：这个为期三年的项目的总体目标是开发和验证新颖的医学成像方法，以解决老年女性的肥胖问题。衰老和缺乏身体活动与身体成分的变化有关，其特征是脂肪量增加和去脂量减少。肌肉相关脂质，特别是肌内甘油三酯（IMTG）对于肌肉质量的影响可能比人们想象的更大。减肥和运动方案对 IMTG 的影响可能会改变肌纤维的方向和密度，从而改变与最大肌力成正比的有效肌肉生理横截面积 (PCSA)。本研究的具体目标是：(1) 建立磁共振成像 (MRI) 和光谱学 (MRS) 的精确度和灵敏度，以量化 IMTG 和组织结构（定义为肌肉质量），(2) 探索这些之间的关系肥胖和习惯性身体活动不同的老年女性的胰岛素作用、肌肉力量和身体功能的肌肉属性，以及（3）运动训练和减肥后。第一个目标将通过采用模仿肌肉分层结构的复杂模型来实现。为实现目标 (2-3)，将招募 50 名老年（65 80 岁）女性，并根据肥胖（正常体重与肥胖）进行筛选，正常体重的女性将进一步根据身体健康（久坐与体力活动）和将使用横截面设计评估肌肉相关的脂质和组织结构。还将对肥胖女性使用平行臂研究设计，将其随机分配到仅通过热量限制诱导的减肥计划以减少 10% 的体重，或为期 6 个月的体重稳定运动计划，以探索该计划的敏感性。 MRI 和 MRS 可测量组织化学已知的肌肉质量扰动。预计运动对肌肉质量的影响将超过身体脂肪（横断面设计）或体重减轻（纵向研究）。此外，由于从能量和肌肉力量的角度来看，肌肉内或肌肉附近所含的脂质被推测会降低肌肉质量，因此 MRI 和 MRS 提供的肌肉质量的定量测量将与胰岛素抵抗以及肌肉强度和性能的临床测量相关。进一步完善和应用质子 MRI 和 MRS 来量化 IMTG 对肌肉质量的影响，将有助于该项目的最终临床转化，即阐明减肥或锻炼可改善因身体紊乱而面临残疾风险的肥胖女性的肌肉质量的机制作品。老年人肥胖与残疾、独立生活能力和生活质量下降有关。从燃料和肌肉力量的角度来看，肌肉内或肌肉附近所含的脂质被推测会降低肌肉质量。无创且准确的医学成像技术（MRI）将用于将营养和运动对因身体成分紊乱而面临残疾风险的肥胖女性大腿肌肉结构和功能的影响联系起来。