Effect of aerobic exercise and amino acid supplementation on mTORC1 signaling and muscle protein synthesis in older adults

2013 ◽  
Vol 23 ◽  
pp. S53
Author(s):  
Melissa M. Markofski ◽  
Kyle L. Timmerman ◽  
Christopher S. Fry ◽  
Blake B. Rasmussen ◽  
Elena Volpi
Keyword(s):  
Older Adults ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Aerobic Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Amino Acid Supplementation ◽  
Acid Supplementation ◽  
Mtorc1 Signaling

204 Awardee Talk: Recent Advances in Protein Nutrition in Horses

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.

scholarly journals Amino Acid Supplementation Increases Lean Body Mass, Basal Muscle Protein Synthesis, and Insulin-Like Growth Factor-I Expression in Older Women

2009 ◽  
Vol 94 (5) ◽  
pp. 1630-1637 ◽  
Author(s):  
Edgar L. Dillon ◽  
Melinda Sheffield-Moore ◽  
Douglas Paddon-Jones ◽  
Charles Gilkison ◽  
Arthur P. Sanford ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Growth Factor ◽  
Older Women ◽  
Lean Body Mass ◽  
Body Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Amino Acid Supplementation ◽  
Factor I

Dietary protein considerations for muscle protein synthesis and muscle mass preservation in older adults

2020 ◽  
pp. 1-11 ◽  
Author(s):  
Eunice T. Olaniyan ◽  
Fiona O’Halloran ◽  
Aoife L. McCarthy
Keyword(s):  
Older Adults ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Mass ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Adult Population ◽  
Anabolic Resistance

Abstract Amino acid bioavailability is critical for muscle protein synthesis (MPS) and preservation of skeletal muscle mass (SMM). Ageing is associated with reduced responsiveness of MPS to essential amino acids (EAA). Further, the older adult population experiences anabolic resistance, leading to increased frailty, functional decline and depleted muscle mass preservation, which facilitates the need for increased protein intake to increase their SMM. This review focuses on the role of proteins in muscle mass preservation and examines the contribution of EAA and protein intake patterns to MPS. Leucine is the most widely studied amino acid for its role as a potent stimulator of MPS, though due to inadequate data little is yet known about the role of other EAA. Reaching a conclusion on the best pattern of protein intake has proven difficult due to conflicting studies. A mixture of animal and plant proteins can contribute to increased MPS and potentially attenuate muscle wasting conditions; however, there is limited research on the biological impact of protein blends in older adults. While there is some evidence to suggest that liquid protein foods with higher than the RDA of protein may be the best strategy for achieving high MPS rates in older adults, clinical trials are warranted to confirm an association between food form and SMM preservation. Further research is warranted before adequate recommendations and strategies for optimising SMM in the elderly population can be proposed.

scholarly journals Mechanisms Linking the Gut-Muscle Axis With Muscle Protein Metabolism and Anabolic Resistance: Implications for Older Adults at Risk of Sarcopenia

2021 ◽  
Vol 12 ◽  
Author(s):  
Konstantinos Prokopidis ◽  
Edward Chambers ◽  
Mary Ni Lochlainn ◽  
Oliver C. Witard
Keyword(s):  
Older Adults ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Gut Microbiota ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Low Grade ◽  
Anabolic Resistance ◽  
Amino Acid Availability ◽  
Low Grade Inflammation

Aging is associated with a decline in skeletal muscle mass and function—termed sarcopenia—as mediated, in part, by muscle anabolic resistance. This metabolic phenomenon describes the impaired response of muscle protein synthesis (MPS) to the provision of dietary amino acids and practice of resistance-based exercise. Recent observations highlight the gut-muscle axis as a physiological target for combatting anabolic resistance and reducing risk of sarcopenia. Experimental studies, primarily conducted in animal models of aging, suggest a mechanistic link between the gut microbiota and muscle atrophy, mediated via the modulation of systemic amino acid availability and low-grade inflammation that are both physiological factors known to underpin anabolic resistance. Moreover, in vivo and in vitro studies demonstrate the action of specific gut bacteria (Lactobacillus and Bifidobacterium) to increase systemic amino acid availability and elicit an anti-inflammatory response in the intestinal lumen. Prospective lifestyle approaches that target the gut-muscle axis have recently been examined in the context of mitigating sarcopenia risk. These approaches include increasing dietary fiber intake that promotes the growth and development of gut bacteria, thus enhancing the production of short-chain fatty acids (SCFA) (acetate, propionate, and butyrate). Prebiotic/probiotic/symbiotic supplementation also generates SCFA and may mitigate low-grade inflammation in older adults via modulation of the gut microbiota. Preliminary evidence also highlights the role of exercise in increasing the production of SCFA. Accordingly, lifestyle approaches that combine diets rich in fiber and probiotic supplementation with exercise training may serve to produce SCFA and increase microbial diversity, and thus may target the gut-muscle axis in mitigating anabolic resistance in older adults. Future mechanistic studies are warranted to establish the direct physiological action of distinct gut microbiota phenotypes on amino acid utilization and the postprandial stimulation of muscle protein synthesis in older adults.

scholarly journals Leucine or carbohydrate supplementation reduces AMPK and eEF2 phosphorylation and extends postprandial muscle protein synthesis in rats

2011 ◽  
Vol 301 (6) ◽  
pp. E1236-E1242 ◽  
Author(s):  
Gabriel J. Wilson ◽  
Donald K. Layman ◽  
Christopher J. Moulton ◽  
Layne E. Norton ◽  
Tracy G. Anthony ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Test Meal ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Adenosine Monophosphate ◽  
Energy Status ◽  
Sprague Dawley ◽  
Translation Elongation ◽  
Cellular Energy ◽  
Mtorc1 Signaling

Muscle protein synthesis (MPS) increases after consumption of a protein-containing meal but returns to baseline values within 3 h despite continued elevations of plasma amino acids and mammalian target of rapamycin (mTORC1) signaling. This study evaluated the potential for supplemental leucine (Leu), carbohydrates (CHO), or both to prolong elevated MPS after a meal. Male Sprague-Dawley rats (∼270 g) trained to consume three meals daily were food deprived for 12 h, and then blood and gastrocnemius muscle were collected 0, 90, or 180 min after a standard 4-g test meal (20% whey protein). At 135 min postmeal, rats were orally administered 2.63 g of CHO, 270 mg of Leu, both, or water (sham control). Following test meal consumption, MPS peaked at 90 min and then returned to basal ( time 0) rates at 180 min, although ribosomal protein S6 kinase and eIF4E-binding protein-1 phosphorylation remained elevated. In contrast, rats administered Leu and/or CHO supplements at 135 min postmeal maintained peak MPS through 180 min. MPS was inversely associated with the phosphorylation states of translation elongation factor 2, the “cellular energy sensor” adenosine monophosphate-activated protein kinase-α (AMPKα) and its substrate acetyl-CoA carboxylase, and increases in the ratio of AMP/ATP. We conclude that the incongruity between MPS and mTORC1 at 180 min reflects a block in translation elongation due to reduced cellular energy. Administering Leu or CHO supplements ∼2 h after a meal maintains cellular energy status and extends the postprandial duration of MPS.

scholarly journals MECHANISMS IN ENDOCRINOLOGY: Exogenous insulin does not increase muscle protein synthesis rate when administered systemically: a systematic review

2015 ◽  
Vol 173 (1) ◽  
pp. R25-R34 ◽  
Author(s):  
Jorn Trommelen ◽  
Bart B L Groen ◽  
Henrike M Hamer ◽  
Lisette C P G M de Groot ◽  
Luc J C van Loon
Keyword(s):  
Systematic Review ◽  
Older Adults ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Exogenous Insulin ◽  
Insulin Administration ◽  
Muscle Protein Synthesis Rate

BackgroundThough it is well appreciated that insulin plays an important role in the regulation of muscle protein metabolism, there is much discrepancy in the literature on the capacity of exogenous insulin administration to increase muscle protein synthesis ratesin vivoin humans.ObjectiveTo assess whether exogenous insulin administration increases muscle protein synthesis rates in young and older adults.DesignA systematic review of clinical trials was performed and the presence or absence of an increase in muscle protein synthesis rate was reported for each individual study arm. In a stepwise manner, multiple models were constructed that excluded study arms based on the following conditions: model 1, concurrent hyperaminoacidemia; model 2, insulin-induced hypoaminoacidemia; model 3, supraphysiological insulin concentrations; and model 4, older, more insulin resistant, subjects.ConclusionsFrom the presented data in the current systematic review, we conclude that: i) exogenous insulin and amino acid administration effectively increase muscle protein synthesis, but this effect is attributed to the hyperaminoacidemia; ii) exogenous insulin administered systemically induces hypoaminoacidemia which obviates any insulin-stimulatory effect on muscle protein synthesis; iii) exogenous insulin resulting in supraphysiological insulin levels exceeding 50 000 pmol/l may effectively augment muscle protein synthesis; iv) exogenous insulin may have a diminished effect on muscle protein synthesis in older adults due to age-related anabolic resistance; and v) exogenous insulin administered systemically does not increase muscle protein synthesis in healthy, young adults.

Sign in / Sign up

Export Citation Format

Share Document