The loss of muscle mass and strength due to aging leads to serious health problems for older adults. Muscle health can be improved by exercise training, but some people improve their strength substantially, whereas others improve little. The reason for this variation is unknown. This study will investigate whether function of the immune system influences how well people respond to exercise. Older Veterans who participate will have their muscle size, strength, and function measured periodically for almost a year. Participants will drink a nutritional supplement or placebo daily and complete a 36 session strength training program. Participants will be vaccinated for tetanus and donate small amounts of blood and muscle tissue during the study so that immune function can be compared to muscle outcomes during training and during a long-term follow-up. The study results should increase the investigators' understanding of the negative effects of aging on muscle and will possibly lead to better strategies for muscle maintenance and rehabilitation for older adults.
Objective: The study will examine the influence of immune function in older adults on improvement of muscle mass, strength, and function by resistance training. The maintenance of those benefits during long term follow-up will also be examined. This objective will be accomplished by a double-blind randomized placebo-controlled trial of a nutritional supplement (Muscle Armor) which evidence suggests can improve immune function, promote muscle growth, and counteract muscle loss. The study premise is that aging results in decreased ability of the immune system to respond to stimuli such as exercise. The study proposes that the supplement will improve muscle health by promoting a shift in immune function of older adults from a pro-inflammatory state towards a state which supports muscle growth and maintenance. Research Plan: The study will randomize Veterans (age 60-80, N=50) to participate in the supplement or placebo groups in a three phase study. The phases of participation correspond to the three specific aims. Aim 1 will determine if 2-weeks of supplementation improves immune function. Humoral immune function will be assessed as the response to vaccination. Innate immune function will be measured as systemic and cellular responses to acute resistance exercise that the investigators' previous studies indicate are affected by aging. Aim 2 will determine if supplementation during 36 sessions of progressive high-intensity resistance training boosts improvement in muscle size (CT scan), strength, and function (gait and balance). Muscle adaptations at the cellular levels will also be measured. Aim 3 will determine if continued supplementation for 26-weeks after completion of exercise training promotes the retention of the gains in muscle size, strength, and function. Multivariable testing will then be used to compare the results between Aims 1, 2, and 3 to determine whether or not immune function is correlated with muscle adaptation to training or detraining. Methods: Participants will undergo nine blood draws and five muscle biopsies of the vastus lateralis over the course of the study so that the effects of the supplement on immune function and cellular adaptations to training can be measured. Three of the blood draws will be used to assess the antibody response to the tetanus, pertussis, and diphtheria vaccine. Muscle and blood will be collected before and after a bout of exercise conducted before and after the 2-weeks of supplementation prior to training. Immune function will be measured using the blood based on pro- and anti-inflammatory cytokine levels, the balance between specific T-cell subpopulations, and the proliferative capacity of mononuclear cells. Immune function will be measured in muscle based on macrophage content of specific cytokines and growth factors. The investigators' previous study showed that these muscle measures strongly correlate with size and strength gain after training. Key signaling pathways including nuclear factor-k B and PI3 kinase will also be measured. The fifth biopsy will be collected post-training to measure adaptation at the cellular level based on changes in number of satellite cells and myonuclei and fiber size. Hypotheses related to these measures will be tested with 80% power to detect at least 0.8 standard deviations difference in means between the supplement and placebo groups. Clinical Relevance: Exercise is clearly able to affect immune function. However, the proposed study will attempt to modulate immune function and determine the effects on exercise outcomes. The study will also examine detraining, an important issue for older adults, that is usually omitted from training studies. Thus, the study will potentially advance the understanding of the mechanisms of muscle gain and loss in older adults, but more importantly, the study will evaluate a nutritional intervention as a complement to exercise for supporting muscle health during aging. Targeting the immune system may be the advantage needed for an older Veteran to successfully maintain or restore the muscle mass, strength, and function that is necessary for personal independence.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
59
Both arms will receive the tetanus, diptheria, and pertussis vaccination after two weeks of treatment with supplement or placebo
Both arms will receive a single bout of resistance exercise twice, before and after two weeks of treatment with supplement or placebo, and be evaluated for the response within blood and muscle
Both arms will receive 36 sessions of progressive high-intensity resistance exercise training (thigh muscle) over the course of approximately 12 weeks.
Both arms will continue to receive treatment with supplement or placebo for approximately 26 weeks after completion of the exercise training. During this time subjects will not be allowed to perform resistance exercise.
Subjects in the supplement group will consume orange-flavored Muscle Armor according to the manufacturer's directions: one serving (approximately 30g, i.e. one scoop provided with the product by its manufacturer), twice daily mixed with 12 ounces (oz) of water beginning after all baseline assessments are performed including assessment of the response to acute exercise and continuing until the end of study participation.
Subjects in the placebo group will consume orange-flavored Kool-Aid (Kraft Foods) according to the manufacturer's directions: one serving (approximately 13g, i.e. one scoop provided with the product by the pharmacy), twice daily mixed with 12 ounces (oz) of water beginning after all baseline assessments are performed including assessment of the response to acute exercise and continuing until the end of study participation.
Central Arkansas Veterans Healthcare System Eugene J. Towbin Healthcare Center, Little Rock, AR
North Little Rock, Arkansas, United States
Change in Plasma Concentration of Antibodies to Pertussis Antigen (1 Week Post-vaccine)
The change in plasma antibody concentration for response to the pertussis antigen within the tetanus, diphtheria, and pertussis (TDAP) vaccination will be measured between baseline and one week post-vaccination.
Time frame: change from baseline at 1 week post-vaccine
Change in Plasma Concentration of Antibodies to Pertussis Antigen (2 Weeks Post-vaccine)
The change in plasma antibody concentration for response to the pertussis antigen within the tetanus, diphtheria, and pertussis (TDAP) vaccination will be measured between baseline and two weeks post-vaccination.
Time frame: change from baseline at 2 weeks post-vaccine
Change in Plasma Concentration of C-Reactive Protein
Plasma c-reactive protein will be measured before and after two weeks of treatment with supplement or placebo.
Time frame: change from baseline at 2 weeks of treatment
Change in the Number of Muscle Macrophages Per Myofiber (Pre- to Post-acute Exercise)
The change in the number of muscle macrophages per myofiber will be calculated for muscle collected before and 72 hours after a single bout of resistance exercise. The changes in macrophage numbers before and after two weeks of treatment with supplement or placebo will be compared.
Time frame: change from baseline at 2 weeks of treatment
Change in Muscle Strength After Exercise Training for 12 Weeks
The change in muscle strength after exercise training will be measured as the difference in one-repetition maximum capability for knee extension from before and after completion of the exercise training program.
Time frame: change from baseline at completion of exercise training phase (12 weeks)
Change in Plasma Concentration of Antibodies to Tetanus Antigen (1 Week Post-vaccine)
The change in plasma antibody concentration for response to the tetanus antigen within the tetanus, diphtheria, and pertussis (TDAP) vaccination will be measured between baseline and one week post-vaccination.
Time frame: change from baseline at 1 week post-vaccine
Change in Plasma Concentration of Antibodies to Tetanus Antigen (2 Weeks Post-vaccine)
The change in plasma antibody concentration for response to the tetanus antigen within the tetanus, diphtheria, and pertussis (TDAP) vaccination will be measured between baseline and two weeks post-vaccination.
Time frame: change from baseline at 2 weeks post-vaccine
Change in Plasma Concentration of Antibodies to Diptheria Antigen (1 Week Post-vaccine)
The change in plasma antibody concentration for response to the diptheria antigen within the tetanus, diphtheria, and pertussis (TDAP) vaccination will be measured between baseline and one week post-vaccination.
Time frame: change from baseline at 1 week post-vaccine
Change in Plasma Concentration of Antibodies to Diptheria Antigen (2 Weeks Post-vaccine)
The change in plasma antibody concentration for response to the diptheria antigen within the tetanus, diphtheria, and pertussis (TDAP) vaccination will be measured between baseline and two weeks post-vaccination.
Time frame: change from baseline at 2 weeks post-vaccine
Number of Muscle Macrophages Per Myofiber (Resting)
The number of muscle macrophages per myofiber will be counted for resting muscle collected before and after two weeks of treatment with supplement or placebo.
Time frame: change from baseline at 2 weeks of treatment
Change in Muscle Size After Exercise Training for 12 Weeks
The change in size of the thigh muscle group after exercise training will be measured as the difference in cross-sectional area based on CT scan before and after completion of the exercise training program.
Time frame: change from baseline at completion of exercise training phase (12 weeks)
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Change in Muscle Strength at Week 16 of the Post-Training Period
The change in muscle strength (one-repetition maximum for knee extension) after completion of the exercise training program will be measured during a follow-up period lacking exercise.
Time frame: difference between baseline and time point one of de-training follow-up period (week 16)
Change in Balance After Exercise Training for 12 Weeks
The change in balance ability after exercise training will be measured as the difference in Berg Balance Scale (Min 0, Max 56, Higher is Better) score between before and after completion of the exercise training program.
Time frame: change from baseline at completion of exercise training (12 weeks)
Change in Balance During the Post-Training Period at 26 Weeks of the Post-training Period
The change in balance based on the Berg Balance Scale (Min 0, Max 56, Higher is Better) score will be measured during a follow-up period lacking exercise after completion of the exercise training program.
Time frame: difference between time of training completion and time point two of de-training follow-up period (26 weeks)
Change in Balance at Week 16 of the Post-Training Period
The change in balance based on the Berg Balance Scale (Min 0, Max 56, Higher is Better) score will be measured during a follow-up period lacking exercise after completion of the exercise training program.
Time frame: difference between time of training completion and time point one of de-training follow-up period (week 16)
Change in Walking Ability After Exercise Training for 12 Weeks
The change in walking ability after exercise training will be measured using the six minute walk test, i.e. the distance the participant can walk without shortness of breath in six minutes.
Time frame: change from baseline at completion of exercise training (12 weeks)
Change in Walking Ability at Week 16 of the Post-Training Period
The change in walking ability based on the six-minute walk test will be measured during a follow-up period lacking exercise after completion of the exercise training program.
Time frame: difference between end of training and time point one of de-training follow-up period (week 16)
Change in Walking Ability at Week 26 of the Post-Training Period
The change in walking ability based on the six-minute walk test will be measured during a follow-up period lacking exercise after completion of the exercise training program.
Time frame: difference between end of training and time point two of de-training follow-up period (week 26)
Change in Gait Speed After Exercise Training for 12 Weeks
The change in gait speed ability after exercise training will be measured as the difference in habitual walking speed for 10 meters before and after completion of the exercise training program.
Time frame: change from baseline at completion of exercise training (12 weeks)
Change in Gait Speed at Week 16 of the Post-Training Period
The change in habitual walking speed over 10 meters will be measured as the difference between values at the end of the training program and time points during a follow-up period lacking exercise.
Time frame: difference between after training and time point one of de-training follow-up period (week 16)
Change in Gait Speed During at Week 26 of the Post-Training Period
The change in habitual walking speed over 10 meters will be measured as the difference between values at the end of the training program and time points during a follow-up period lacking exercise.
Time frame: difference between after training and time point two of de-training follow-up period (week 26)
Change in Muscle Size at Week 26 of the Post-Training Period
The change in size of the thigh muscle group during the post-training period will be measured as the difference in cross-sectional area based on CT scan at the end of the training program and at the end of study participation.
Time frame: difference between baseline and time point two of de-training follow-up period (week 26)
Change in Timed Up and Go After Exercise Training for 12 Weeks
The change in time required to rise from a chair, walk three meters, turn around, walk back to the chair, and sit down will be measured as the difference between before and after completion of the exercise training program.
Time frame: change from baseline at completion of exercise training (12 weeks)
Change in Timed Up and Go at Week 16 of the Post-Training Period
The change in time required to rise from a chair, walk three meters, turn around, walk back to the chair, and sit down will be measured as the difference between time points at the end of the training program and during the post-training period.
Time frame: difference between after training and time point one of de-training follow-up period (week 16)
Change in Timed Up and Go at Week 26 of the Post-Training Period
The change in time required to rise from a chair, walk three meters, turn around, walk back to the chair, and sit down will be measured as the difference between time points at the end of the training program and during the post-training period.
Time frame: difference between after training and time point two of de-training follow-up period (week 26)
Percent Change in Resting Muscle Concentration of Interleukin-1 Beta
The muscle concentration of interleukin-1 beta will be measured before and after two weeks of treatment with supplement or placebo.
Time frame: change from baseline at 2 weeks of treatment
Change in Muscle Concentration of Interleukin-1 Beta (Pre- to Post-acute Exercise)
The change in the muscle concentration of interleukin-1 beta before and one hour after a single bout of resistance exercise. The changes in macrophage numbers before and after two weeks of treatment with supplement or placebo will be compared.
Time frame: change from baseline at 2 weeks of treatment
Change in Resting Muscle Atrophy Gene MURF Expression
The change in resting muscle atrophy gene MURF expression will be measured before and after two weeks of treatment with supplement or placebo.
Time frame: percent change from baseline at 2 weeks of treatment
Change in Resting Muscle Atrophy Gene MURF Expression (Post-acute Exercise)
The change in resting muscle atrophy gene MURF expression will be measured before and 72 hours after a single bout of exercise completed before and after two weeks of treatment with supplement or placebo.
Time frame: change from baseline at 2 weeks of treatment
Change in Resting Muscle Protein Kinase B
The change in resting muscle Protein Kinase B will be measured before and after two weeks of treatment with supplement or placebo.
Time frame: change from baseline at 2 weeks of treatment
Change in Muscle Protein Kinase B (Post-acute Exercise)
The change in muscle Protein Kinase B will be measured before and 72 hours after a single bout of exercise completed before and after two weeks of treatment with supplement or placebo.
Time frame: change from baseline at 2 weeks of treatment
Change in Number of Muscle Satellite Cells After Exercise Training for 12 Weeks
The change in the satellite cell content of muscle will be measured as the difference in the number of satellite cells in muscle before and after completion of the exercise training program.
Time frame: change from baseline at completion of exercise training (12 weeks)
Change in Number of Myonuclei After Exercise Training for 12 Weeks
The change in the myonuclear content of muscle will be measured as the difference in the number of myonuclei in muscle before and after completion of the exercise training program.
Time frame: change from baseline at completion of exercise training (12 weeks)
Change in Muscle Fiber Size After Exercise Training for 12 Weeks
The change in the muscle fiber size will be measured as the difference in fiber size before and after completion of the exercise training program.
Time frame: change from baseline at completion of exercise training (12 weeks)