Location: Jean Mayer Human Nutrition Research Center On Aging
2015 Annual Report
Objectives
LAB NAME: Nutrition, Exercise Physiology, and Sarcopenia
1. Characterize the mechanisms associated with nutritional and contraction-related mediators of anabolic resistance associated with advancing age and/or obesity in animal models and humans.
2. Determine the effects of structured, long term interventions of aerobic walking and resistance physical activity on physical functioning in older adults with chronic kidney disease or limited mobility.
3. Determine the effects of structured, long term interventions of aerobic walking and resistance physical activity on cognitive functioning in older adults with chronic kidney disease or limited mobility.
Approach
LAB NAME: Nutrition, Exercise Physiology, and Sarcopenia
Sarcopenia, the age-associated loss in skeletal muscle mass and function, is a contributing factor to the observed declines in physiological capacity and physical functioning with advancing age. The overall theme of this project will be to conduct basic and clinical studies focused on the identification, evaluation, and understanding of nutritional and physical activity interventions that possess anabolic properties in skeletal muscle and have the potential to prevent or reverse impaired motor and cognitive performance and/or physical dysfunction in older individuals. Our basic research program will focus on understanding the molecular mechanisms associated with age-related anabolic resistance in skeletal muscle. These basic studies will be uniquely synergized with our clinical/translational studies designed to evaluate the potential efficacy of nutritional and exercise interventions in older adults. Our proposed clinical studies will further seek to understand the role of structured physical activity and nutritional supplementation on changes in physical function and disability in older adults with mobility limitations as a consequence of anabolic resistance and/or sarcopenia. In addition, we will also examine the role of structured physical activity on changes in cognition and the role of physical activity on dementia risk. The pairing of clinical studies examining the influence of protein nutrition and physical activity on sarcopenia with basic approaches that identify the molecular landscape and potential targets in skeletal muscle for preventive interventions (nutritional, physical activity) may accelerate our ability to translate these findings to aging people.
Progress Report
This report documents research conducted under 1 project in a Non-Assistance Cooperative Agreement between ARS and TUFTS UNIVERSITY. Additional details for the research are associated with project 8050-51000-091-01S, Nutrition, Physical Activity and Sarcopenia in the Elderly.
Our project has made initial progress on all objectives outlined in our project plan. In the current project year, we have fully met the majority of our approved milestones. Work on objectives 1. (Characterize the mechanisms associated with nutritional and contraction-related mediators of anabolic resistance associated with advancing age and/or obesity in animal models and humans), 2. (Determine the effects of structured, long term interventions of aerobic walking and resistance physical activity on physical functioning in older adults with chronic kidney disease or limited mobility) and 3. (Determine the effects of structured, long term interventions of aerobic walking and resistance physical activity on cognitive functioning in older adults with chronic kidney disease or limited mobility) has been initiated. Substantial progress has been made on Objective 1 with recent work illustrating an age-related impaired suppression of micro-RNA expression in response the resistance exercise in healthy older adults (Publication in FASEB Journal). For objectives 2 and 3, the proposed clinical trials have been initiated.
Accomplishments
1. Metabolites related to gut bacterial metabolism are associated with physical function in older adults. Identification of mechanisms underlying physical function are important for addressing the growing challenge that health care will face with physical disablement in the expanding aging population. ARS funded researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Massachusetts, used metabolic profiling to provide insight into biologic mechanisms that may underlie physical function by examining the association between baseline and the 6-month change in serum amino acids, fatty acids, and acylcarnitines with baseline and the 6-month change in muscle strength in response to 6 months of a combined resistance exercise and nutritional supplementation intervention in functionally-limited older adults. Metabolites related to gut bacterial metabolism (produced by microbes in the gut) were associated with function at baseline, with the 6-month change in function. Collectively, these data suggest that gut microbial metabolism may be involved in mechanisms that underlie muscle strength and physical function in older adults.
2. Diminished skeletal muscle microRNA expression with aging alters muscle plasticity. Older individuals have a reduced capacity to induce muscle growth with resistance exercise (RE), which may contribute to the age-induced loss of muscle mass and function, sarcopenia. ARS funded researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Massachusetts, tested the novel hypothesis that dysregulation of microRNAs (miRNAs) may contribute to reduced muscle plasticity with aging. Their research confirmed a reduced adaptability of aging muscle to exercise and identified a specific microRNA as an important regulator of the transcriptional response to exercise and reduced lean mass in aging men. This work identifies a mechanistic role of miRNA in the adaptation of muscle to exercise and other interventions that cause muscle growth. In addition, advancing age is associated with dysregulation of miRNA expression in skeletal muscle.
