Muscle Protein Synthesis and Muscle Mass in Healthy Older Men

Abstract Background Fortetropin is a proteo-lipid complex made from fertilized egg yolk and, in young men, has been shown to increase lean body mass. Methods The purpose of this study was to examine the effects of 21 days of Fortetropin supplementation on the fractional synthetic rate (FSR) of muscle protein in 10 healthy, older men and 10 women (66.4 ± 4.5 y). We used 2H2O labeling to measure FSR of multiple muscle protein ontologies. D3-creatine dilution was used to determine muscle mass at baseline. Subjects ingested 70% 2H2O for 21 day and saliva samples were collected to determine body 2H2O enrichment. A microbiopsy was obtained from the m. vastus lateralis on Day 21. Subjects were randomly assigned to Fortetropin (19.8 g/d) or placebo (cheese powder, 19.8 g/d). Results Restricting kinetic data to proteins with ≥2 peptides measured in at least 4 subjects per group resulted in 117 proteins meeting these criteria. The mean FSR for a majority of proteins in several muscle gene ontologies was higher in the Fortetropin group compared to placebo (32/38 myofibril proteins, 33/44 sarcoplasmic proteins, and 12/17 mitochondrial proteins) and this proportion was significantly different between groups using a binomial test and were independent of sex or baseline muscle mass. Conclusions The overall magnitude of the difference in muscle protein FSR of Fortetropin from placebo was 18%, with multiple gene ontologies affected. While these results should be confirmed in larger cohorts, they suggest that Fortetropin supplementation is effective for promoting muscle protein synthesis in older people.

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Faculty Opinions recommendation of Effect of age on basal muscle protein synthesis and mTORC1 signaling in a large cohort of young and older men and women.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725380242.793518281 ◽

2016 ◽

Author(s):

James Timmons ◽

Iain Gallagher

Keyword(s):

Protein Synthesis ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Older Men ◽

Large Cohort ◽

Men And Women ◽

Mtorc1 Signaling ◽

Older Men And Women ◽

Effect Of Age

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204 Awardee Talk: Recent Advances in Protein Nutrition in Horses

Journal of Animal Science ◽

10.1093/jas/skab235.198 ◽

2021 ◽

Vol 99 (Supplement_3) ◽

pp. 109-109

Author(s):

Kristine Urschel

Keyword(s):

Protein Synthesis ◽

Amino Acid ◽

Muscle Mass ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Protein Digestibility ◽

Future Research ◽

Amino Acid Supplementation ◽

Protein Nutrition ◽

Active Research

Abstract Protein has been recognized as an essential nutrient for animals for well over 100 years. Protein plays many important structural and metabolic roles, and some of its component amino acids have additional functions, including as regulatory molecules, as energy substrates and in the synthesis of other non-protein molecules. Skeletal muscle makes up approximately 50% of body weight in horses, with protein being the major non-water component. As an athletic species, the development and maintenance of muscle mass is of the utmost importance in horses. Because muscle mass is largely determined by the balance of rates of muscle protein synthesis and breakdown, understanding how these pathways are regulated and influenced by dietary protein and amino acid provision is essential. Historically, much research regarding protein nutrition in horses has focused on the protein digestibility of different feed ingredients, and the adequacy of different protein sources in supporting the growth and maintenance of horses. This presentation will focus on some of the current areas of active research relating to protein nutrition in horses: the activation of the signaling pathways that regulate muscle protein synthesis, amino acid supplementation in athletic horses, protein metabolism in aged and horses and those with insulin dysregulation, and amino acid and protein nutrition in predominantly forage-fed horses. There are many exciting opportunities for future research in the area of protein and amino acid nutrition in horses across the lifespan.

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Higher skeletal muscle protein synthesis and lower breakdown after chemotherapy in cachectic mice

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2001.281.1.r133 ◽

2001 ◽

Vol 281 (1) ◽

pp. R133-R139 ◽

Cited By ~ 20

Author(s):

S. E. Samuels ◽

A. L. Knowles ◽

T. Tilignac ◽

E. Debiton ◽

J. C. Madelmont ◽

...

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Muscle Mass ◽

Skeletal Muscle Mass ◽

Cancer Cachexia ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Human Condition ◽

Skeletal Muscle Protein ◽

Tumor Bearing

The influence of cancer cachexia and chemotherapy and subsequent recovery of skeletal muscle protein mass and turnover was investigated in mice. Cancer cachexia was induced using colon 26 adenocarcinoma, which is characteristic of the human condition, and can be cured with 100% efficacy using an experimental nitrosourea, cystemustine (C6H12CIN3O4S). Reduced food intake was not a factor in these studies. Three days after cachexia began, healthy and tumor-bearing mice were given a single intraperitoneal injection of cystemustine (20 mg/kg). Skeletal muscle mass in tumor-bearing mice was 41% lower ( P < 0.05) than in healthy mice 2 wk after cachexia began. Skeletal muscle wasting was mediated initially by decreased protein synthesis (−38%; P < 0.05) and increased degradation (+131%; P < 0.05); later wasting resulted solely from decreased synthesis (∼−54 to −69%; P < 0.05). Acute cytotoxicity of chemotherapy did not appear to have an important effect on skeletal muscle protein metabolism in either healthy or tumor-bearing mice. Recovery began 2 days after treatment; skeletal muscle mass was only 11% lower than in healthy mice 11 days after chemotherapy. Recovery of skeletal muscle mass was affected initially by decreased protein degradation (−80%; P < 0.05) and later by increased protein synthesis (+46 to +73%; P < 0.05) in cured compared with healthy mice. This study showed that skeletal muscle wasted from cancer cachexia and after chemotherapeutic treatment is able to generate a strong anabolic response by making powerful changes to protein synthesis and degradation.

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Ingestion of Casein in a Milk Matrix Modulates Dietary Protein Digestion and Absorption Kinetics but Does Not Modulate Postprandial Muscle Protein Synthesis in Older Men

Journal of Nutrition ◽

10.3945/jn.115.213710 ◽

2015 ◽

Vol 145 (7) ◽

pp. 1438-1445 ◽

Cited By ~ 22

Author(s):

Tyler A Churchward-Venne ◽

Tim Snijders ◽

Armand MA Linkens ◽

Henrike M Hamer ◽

Janneau van Kranenburg ◽

...

Keyword(s):

Protein Synthesis ◽

Dietary Protein ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Older Men ◽

Protein Digestion ◽

Absorption Kinetics

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Tart cherry concentrate does not enhance muscle protein synthesis response to exercise and protein in healthy older men

Experimental Gerontology ◽

10.1016/j.exger.2018.06.007 ◽

2018 ◽

Vol 110 ◽

pp. 202-208 ◽

Cited By ~ 4

Author(s):

Sarah R. Jackman ◽

Matthew S. Brook ◽

Richard M. Pulsford ◽

Emma J. Cockcroft ◽

Matthew I. Campbell ◽

...

Keyword(s):

Protein Synthesis ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Older Men ◽

Tart Cherry ◽

Response To Exercise

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Aging, exercise, and muscle protein metabolism

Journal of Applied Physiology ◽

10.1152/japplphysiol.91551.2008 ◽

2009 ◽

Vol 106 (6) ◽

pp. 2040-2048 ◽

Cited By ~ 197

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.

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

Canadian Journal of Applied Physiology ◽

10.1139/h01-033 ◽

2001 ◽

Vol 26 (6) ◽

pp. 588-606 ◽

Cited By ~ 18

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

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

REVISTA CIÊNCIAS EM SAÚDE ◽

10.21876/rcshci.v11i3.1135 ◽

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.

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