Muscle Protein Metabolism in the Elderly: Influence of Exercise and Nutrition

2001 ◽  
Vol 26 (6) ◽  
pp. 588-606 ◽  
Author(s):  
Kevin D. Tipton
Keyword(s):  
Protein Synthesis ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Effective Means ◽  
The Elderly ◽  
Protein Breakdown ◽  
Small Magnitude ◽  
Muscle Protein Breakdown ◽  
Metabolic Basis

Although the causes of sarcopenia are multi-factorial, at least some, such as poor nutrition and inactivity, may be preventable. Changes in muscle mass must be a result of net muscle protein breakdown over that particular time period. Stable isotope methodology has been used to examine the metabolic basis of muscle loss. Net muscle protein breakdown may occur due to a decrease in the basal level of muscle protein synthesis. However, changes of this type would likely be of small magnitude and undetectable by current methodology. Hormonal mediators may also be important, especially in association with forced inactivity. Net muscle protein breakdown may be also attributed to alterations in the periods of net muscle protein synthesis and breakdown each day. Reduced activity, combined with ineffectual nutrient intake, could lead to decreased net muscle protein balance. Chronic resistance exercise training clearly is an effective means of increasing muscle mass and strength in elderly individuals. Although sometimes limited, acute metabolic studies provide valuable information for maintenance of muscle mass with age. Key words: sarcopenia, inactivity, strength training, muscle protein synthesis, muscle hypertrophy

scholarly journals Combined in vivo muscle mass, muscle protein synthesis and muscle protein breakdown measurement: a ‘Combined Oral Stable Isotope Assessment of Muscle (COSIAM)’ approach

GeroScience ◽  
2021 ◽  
Author(s):  
Jessica Cegielski ◽  
Daniel J. Wilkinson ◽  
Matthew S. Brook ◽  
Catherine Boereboom ◽  
Bethan E. Phillips ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Stable Isotope ◽  
Muscle Mass ◽  
Protein Turnover ◽  
Skeletal Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Protein Breakdown ◽  
Muscle Protein Breakdown

AbstractOptimising approaches for measuring skeletal muscle mass and turnover that are widely applicable, minimally invasive and cost effective is crucial in furthering research into sarcopenia and cachexia. Traditional approaches for measurement of muscle protein turnover require infusion of expensive, sterile, isotopically labelled tracers which limits the applicability of these approaches in certain populations (e.g. clinical, frail elderly). To concurrently quantify skeletal muscle mass and muscle protein turnover i.e. muscle protein synthesis (MPS) and muscle protein breakdown (MPB), in elderly human volunteers using stable-isotope labelled tracers i.e. Methyl-[D3]-creatine (D3-Cr), deuterium oxide (D2O), and Methyl-[D3]-3-methylhistidine (D3-3MH), to measure muscle mass, MPS and MPB, respectively. We recruited 10 older males (71 ± 4 y, BMI: 25 ± 4 kg.m2, mean ± SD) into a 4-day study, with DXA and consumption of D2O and D3-Cr tracers on day 1. D3-3MH was consumed on day 3, 24 h prior to returning to the lab. From urine, saliva and blood samples, and a single muscle biopsy (vastus lateralis), we determined muscle mass, MPS and MPB. D3-Cr derived muscle mass was positively correlated to appendicular fat-free mass (AFFM) estimated by DXA (r = 0.69, P = 0.027). Rates of cumulative myofibrillar MPS over 3 days were 0.072%/h (95% CI, 0.064 to 0.081%/h). Whole-body MPB over 6 h was 0.052 (95% CI, 0.038 to 0.067). These rates were similar to previous literature. We demonstrate the potential for D3-Cr to be used alongside D2O and D3-3MH for concurrent measurement of muscle mass, MPS, and MPB using a minimally invasive design, applicable for clinical and frail populations.

Aging, exercise, and muscle protein metabolism

2009 ◽  
Vol 106 (6) ◽  
pp. 2040-2048 ◽  
Author(s):  
René Koopman ◽  
Luc J. C. van Loon
Keyword(s):  
Physical Activity ◽  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Food Intake ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
The Elderly ◽  
Age Related

Aging is accompanied by a progressive loss of skeletal muscle mass and strength, leading to the loss of functional capacity and an increased risk of developing chronic metabolic disease. The age-related loss of skeletal muscle mass is attributed to a disruption in the regulation of skeletal muscle protein turnover, resulting in an imbalance between muscle protein synthesis and degradation. As basal (fasting) muscle protein synthesis rates do not seem to differ substantially between the young and elderly, many research groups have started to focus on the muscle protein synthetic response to the main anabolic stimuli, i.e., food intake and physical activity. Recent studies suggest that the muscle protein synthetic response to food intake is blunted in the elderly. The latter is now believed to represent a key factor responsible for the age-related decline in skeletal muscle mass. Physical activity and/or exercise stimulate postexercise muscle protein accretion in both the young and elderly. However, the latter largely depends on the timed administration of amino acids and/or protein before, during, and/or after exercise. Prolonged resistance type exercise training represents an effective therapeutic strategy to augment skeletal muscle mass and improve functional performance in the elderly. The latter shows that the ability of the muscle protein synthetic machinery to respond to anabolic stimuli is preserved up to very old age. Research is warranted to elucidate the interaction between nutrition, exercise, and the skeletal muscle adaptive response. The latter is needed to define more effective strategies that will maximize the therapeutic benefits of lifestyle intervention in the elderly.

Effect of exercise and recovery on muscle protein synthesis in human subjects

1990 ◽  
Vol 259 (4) ◽  
pp. E470-E476 ◽  
Author(s):  
F. Carraro ◽  
C. A. Stuart ◽  
W. H. Hartl ◽  
J. Rosenblatt ◽  
R. R. Wolfe
Keyword(s):  
Protein Synthesis ◽  
Aerobic Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Nitrogen Excretion ◽  
Control Group ◽  
Protein Breakdown ◽  
Muscle Protein Breakdown ◽  
Synthetic Rate ◽  
Fractional Synthetic Rate

Previous studies using indirect means to assess the response of protein metabolism to exercise have led to conflicting conclusions. Therefore, in this study we have measured the rate of muscle protein synthesis in normal volunteers at rest, at the end of 4 h of aerobic exercise (40% maximal O2 consumption), and after 4 h of recovery by determining directly the rate of incorporation of 1,2-[13C]leucine into muscle. The rate of muscle protein breakdown was assessed by 3-methylhistidine (3-MH) excretion, and total urinary nitrogen excretion was also measured. There was an insignificant increase in 3-MH excretion in exercise of 37% and a significant increase (P less than 0.05) of 85% during 4 h of recovery from exercise (0.079 +/- 0.008 vs. 0.147 +/- 0.0338 mumol.kg-1.min-1 for rest and recovery from exercise, respectively). Nonetheless, there was no effect of exercise on total nitrogen excretion. Muscle fractional synthetic rate was not different in the exercise vs. the control group at the end of exercise (0.0417 +/- 0.004 vs. 0.0477 +/- 0.010%/h for exercise vs. control), but there was a significant increase in fractional synthetic rate in the exercise group during the recovery period (0.0821 +/- 0.006 vs. 0.0654 +/- 0.012%/h for exercise vs. control, P less than 0.05). Thus we conclude that although aerobic exercise may stimulate muscle protein breakdown, this does not result in a significant depletion of muscle mass because muscle protein synthesis is stimulated in recovery.

scholarly journals The anabolic role of plant-based proteins in response to chronic resistance exercise

2021 ◽  
Vol 11 (3) ◽  
pp. 14-23
Author(s):  
Carina Sousa Santos ◽  
Eudes Souza Oliveira Júnior ◽  
Marcus James Lopes de Sá ◽  
Elizabethe Adriana Esteves
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
The Elderly ◽  
Food Sources ◽  
Dietary Adequacy ◽  
The Face

Proper maintenance of skeletal muscle mass is essential to prevent sarcopenia and ensure health and quality of life as aging progress. The two determinants of muscle protein synthesis are the increased load on skeletal muscle through resistance exercise and protein intake. For an effective result of maintaining or increasing muscle mass, it is relevant to consider the quantitative and adequate intake of protein, and the dietary source of protein since the plant-based protein has differences in comparison to animals that limit its anabolic capacity. Given the increase in vegetarianism and the elderly population, which consumes fewer food sources of animal protein, the importance of understanding how protein of plant-based protein can sustain muscle protein synthesis in the long term when associated with resistance exercise is justified, as well as the possibilities of dietary adequacy in the face of this demand.

scholarly journals Dietary protein and exercise training in ageing

2010 ◽  
Vol 70 (1) ◽  
pp. 104-113 ◽  
Author(s):  
René Koopman
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Exercise Training ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Human Subjects ◽  
The Elderly ◽  
Age Related

Ageing is accompanied by a progressive loss of skeletal muscle mass and strength, leading to the loss of functional capacity and an increased risk for developing chronic metabolic diseases such as diabetes. The age-related loss of skeletal muscle mass results from a chronic disruption in the balance between muscle protein synthesis and degradation. As basal muscle protein synthesis rates are likely not different between healthy young and elderly human subjects, it was proposed that muscles from older adults lack the ability to regulate the protein synthetic response to anabolic stimuli, such as food intake and physical activity. Indeed, the dose–response relationship between myofibrillar protein synthesis and the availability of essential amino acids and/or resistance exercise intensity is shifted down and to the right in elderly human subjects. This so-called ‘anabolic resistance’ represents a key factor responsible for the age-related decline in skeletal muscle mass. Interestingly, long-term resistance exercise training is effective as a therapeutic intervention to augment skeletal muscle mass, and improves functional performance in the elderly. The consumption of different types of proteins, i.e. protein hydrolysates, can have different stimulatory effects on muscle protein synthesis in the elderly, which may be due to their higher rate of digestion and absorption. Current research aims to elucidate the interactions between nutrition, exercise and the skeletal muscle adaptive response that will define more effective strategies to maximise the therapeutic benefits of lifestyle interventions in the elderly.

Resistance exercise and nutrition to counteract muscle wasting

2009 ◽  
Vol 34 (5) ◽  
pp. 817-828 ◽  
Author(s):  
Jonathan P. Little ◽  
Stuart M. Phillips
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Effective Means ◽  
Resistance Exercise Training ◽  
Highly Effective

Loss of muscle mass is an unfavourable consequence of aging and many chronic diseases. The debilitating effects of muscle loss include declines in physical function and quality of life and increases in morbidity and mortality. Loss of muscle mass is the result of a decrease in muscle protein synthesis, an increase in muscle protein degradation, or a combination of both. Much research on muscle wasting has tended to focus on preventing muscle protein breakdown, and less attention has been paid to providing adequate stimulation to increase muscle protein synthesis. In this review, we present evidence to suggest that interventions aimed at increasing muscle protein synthesis represent the most effective countermeasure for preventing, delaying, or reversing the loss of skeletal muscle mass experienced in various muscle wasting conditions. Based on results from acute and chronic studies in humans in a wide variety of wasting conditions, we propose that resistance exercise training combined with appropriately timed protein (likely leucine-rich) ingestion represents a highly effective means to promote muscle hypertrophy, and may represent a highly effective treatment strategy to counteract the muscle wasting tassociated with aging and chronic disease.

Amino acid repletion does not decrease muscle protein catabolism during hemodialysis

2007 ◽  
Vol 292 (6) ◽  
pp. E1534-E1542 ◽  
Author(s):  
Dominic S. C. Raj ◽  
Oladipo Adeniyi ◽  
Elizabeth A. Dominic ◽  
Michel A. Boivin ◽  
Sandra McClelland ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Protein Breakdown ◽  
Protein Catabolism ◽  
Acid Infusion ◽  
Amino Acid Infusion ◽  
Muscle Protein Breakdown

Intradialytic protein catabolism is attributed to loss of amino acids in the dialysate. We investigated the effect of amino acid infusion during hemodialysis (HD) on muscle protein turnover and amino acid transport kinetics by using stable isotopes of phenylalanine, leucine, and lysine in eight patients with end-stage renal disease (ESRD). Subjects were studied at baseline (pre-HD), 2 h of HD without amino acid infusion (HD-O), and 2 h of HD with amino acid infusion (HD+AA). Amino acid depletion during HD-O augmented the outward transport of amino acids from muscle into the vein. Increased delivery of amino acids to the leg during HD+AA facilitated the transport of amino acids from the artery into the intracellular compartment. Increase in muscle protein breakdown was more than the increase in synthesis during HD-O (46.7 vs. 22.3%, P < 0.001). Net balance (nmol·min−1·100 ml −1) was more negative during HD-O compared with pre-HD (−33.7 ± 1.5 vs. −6.0 ± 2.3, P < 0.001). Despite an abundant supply of amino acids, the net balance (−16.9 ± 1.8) did not switch from net release to net uptake. HD+AA induced a proportional increase in muscle protein synthesis and catabolism. Branched chain amino acid catabolism increased significantly from baseline during HD-O and did not decrease during HD+AA. Protein synthesis efficiency, the fraction of amino acid in the intracellular pool that is utilized for muscle protein synthesis decreased from 42.1% pre-HD to 33.7 and 32.6% during HD-O and HD+AA, respectively ( P < 0.01). Thus amino acid repletion during HD increased muscle protein synthesis but did not decrease muscle protein breakdown.

Acute effects of resistance exercise on muscle protein synthesis rate in young and elderly men and women

1993 ◽  
Vol 265 (2) ◽  
pp. E210-E214 ◽  
Author(s):  
K. E. Yarasheski ◽  
J. J. Zachwieja ◽  
D. M. Bier
Keyword(s):  
Protein Synthesis ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
The Elderly ◽  
Whole Body ◽  
Synthesis Rate ◽  
Protein Breakdown ◽  
Resistance Exercise Training

Muscle mass and function are improved in the elderly during resistance exercise training. These improvements must result from alterations in the rates of muscle protein synthesis and breakdown. We determined the rate of quadriceps muscle protein synthesis using the in vivo rate of incorporation of intravenously infused [13C]leucine into mixed-muscle protein in both young (24 yr) and elderly (63-66 yr) men and women before and at the end of 2 wk of resistance exercise training. Before training, the fractional rate of muscle protein synthesis was lower in the elderly than in the young (0.030 +/- 0.003 vs. 0.049 +/- 0.004%/h; P = 0.004) but increased (P < 0.03) to a comparable rate of muscle protein synthesis in both young (0.075 +/- 0.009%/h) and elderly subjects (0.076 +/- 0.011%/h) after 2 wk of exercise. In the elderly, muscle mass, 24-h urinary 3-methylhistidine and creatinine excretion, and whole body protein breakdown rate determined during the [13C]leucine infusion were not changed after 2 wk of exercise. These findings demonstrate that, during the initial phase of a resistance exercise training program, a marked increase in quadriceps muscle protein synthesis rate occurs in elderly and young adults without an increase in the rate of whole body protein breakdown. In the elderly, this was not accompanied by an increase in urinary 3-methylhistidine excretion, an index of myofibrillar protein breakdown.

scholarly journals Short-term insulin and nutritional energy provision do not stimulate muscle protein synthesis if blood amino acid availability decreases

2005 ◽  
Vol 289 (6) ◽  
pp. E999-E1006 ◽  
Author(s):  
Jill A. Bell ◽  
Satoshi Fujita ◽  
Elena Volpi ◽  
Jerson G. Cadenas ◽  
Blake B. Rasmussen
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Insulin Infusion ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Protein Breakdown ◽  
Short Term ◽  
Muscle Protein Breakdown ◽  
Amino Acid Availability ◽  
Leg Muscle

Muscle protein synthesis requires energy and amino acids to proceed and can be stimulated by insulin under certain circumstances. We hypothesized that short-term provision of insulin and nutritional energy would stimulate muscle protein synthesis in healthy subjects only if amino acid availability did not decrease. Using stable isotope techniques, we compared the effects on muscle phenylalanine kinetics across the leg of an amino acid-lowering, high-energy (HE, n = 6, 162 ± 20 kcal/h) hyperglycemic hyperlipidemic hyperinsulinemic clamp with systemic insulin infusion to a low-energy (LE, n = 6, 35 ± 3 kcal/h, P < 0.05 vs. HE) euglycemic hyperinsulinemic clamp with local insulin infusion in the femoral artery. Basal blood phenylalanine concentrations and phenylalanine net balance, muscle protein breakdown, and synthesis (nmol·min−1·100 g leg muscle−1) were not different between groups. During insulin infusion, femoral insulinemia increased to a similar extent between groups and blood phenylalanine concentration decreased 27 ± 3% in the HE group but only 9 ± 2% in the LE group ( P < 0.01 HE vs. LE). Phenylalanine net balance increased in both groups, but the change was greater ( P < 0.05) in the LE group. Muscle protein breakdown decreased in the HE group (58 ± 12 to 35 ± 7 nmol·min−1·100 g leg muscle−1) and did not change in the LE group. Muscle protein synthesis was unchanged in the HE group (39 ± 6 to 30 ± 7 nmol·min−1·100 g leg muscle−1) and increased ( P < 0.05) in the LE group (41 ± 9 to 114 ± 26 nmol·min−1·100 g leg muscle−1). We conclude that amino acid availability is an important factor in the regulation of muscle protein synthesis in response to insulin, as decreased blood amino acid concentrations override the positive effect of insulin on muscle protein synthesis even if excess energy is provided.

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