Two Weeks of Reduced Activity Decreases Leg Lean Mass and Induces “Anabolic Resistance” of Myofibrillar Protein Synthesis in Healthy Elderly

Breen, Leigh; Stokes, Keith; Churchward‐Venne, Tyler A.; Moore, Daniel R.; Baker, Stephen K.; Smith, Kenneth; Atherton, Philip J.; Phillips, Stuart M.

doi:10.1210/jc.2013-1502

Cited by 334 publications

(409 citation statements)

References 34 publications

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“…Such anabolic resistance has not only been conjectured by us and others to contribute to the sarcopenia of ageing but it also appears to be a common feature of many kinds of muscle atrophy (e.g. with immobilization (Glover et al 2008), reduced physical activity (Breen et al 2013), heart failure (Toth et al 2010), obesity (Guillet et al 2009;Murton et al 2015) and cancer ), suggesting a final common pathway for a variety of insults resulting in diminished anabolism. Whereas the regulatory mechanisms of anabolic resistance remain poorly defined, possible links between reduced muscle MBF and diminished anabolic responses to plasma nutrient availability may be a general feature of a number of conditions.…”

Section: Discussionmentioning

confidence: 93%

Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men

Phillips

Atherton

Varadhan

et al. 2016

Appl. Physiol. Nutr. Metab.

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Section: Discussionmentioning

confidence: 93%

Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men

Phillips

Atherton

Varadhan

et al. 2016

Appl. Physiol. Nutr. Metab.

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“…Exercise plays an integral role in maintaining muscle mass and function during advanced age [4]. Furthermore, exercise can improve cardiovascular function, metabolic health, muscular function, body composition, and quality of life, in aging cohorts [5,6,7].…”

Section: Introductionmentioning

confidence: 99%

High-intensity interval training (HIIT) increases insulin-like growth factor-I (IGF-I) in sedentary aging men but not masters’ athletes: an observational study

et al. 2016

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“…Similarly, physical activity is a prerequisite for maintenance of a healthy muscle mass. For example, inactivity (6,20) causes muscle atrophy by inducing "anabolic resistance" to nutrition. Conversely, physical activity/exercise potentiates the trophic effects of nutrition; i.e., anabolic responses are greater when exercise and nutrient intake are combined to facilitate adaptation and repair.…”

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confidence: 99%

Intake of low-dose leucine-rich essential amino acids stimulates muscle anabolism equivalently to bolus whey protein in older women at rest and after exercise

Bukhari

Phillips

Wilkinson

et al. 2015

American Journal of Physiology-Endocrinology and Metabolism

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PJ. Intake of low-dose leucine-rich essential amino acids stimulates muscle anabolism equivalently to bolus whey protein in older women at rest and after exercise. Am J Physiol Endocrinol Metab 308: E1056-E1065, 2015. First published March 31, 2015; doi:10.1152/ajpendo.00481.2014.-Dysregulated anabolic responses to nutrition/exercise may contribute to sarcopenia; however, these characteristics are poorly defined in female populations. We determined the effects of two feeding regimes in older women (66 Ϯ 2.5 yr; n ϭ 8/group): bolus whey protein (WP-20 g) or novel low-dose leucine-enriched essential amino acids (EAA) [LEAA; 3 g (40% leucine)]. Using [ 13 C6]phenylalanine infusions, we quantified muscle (MPS) and albumin (APS) protein synthesis at baseline and in response to both feeding (FED) and feeding plus exercise (FED-EX; 6 ϫ 8 knee extensions at 75% 1-repetition maximum). We also quantified plasma insulin/AA concentrations, whole leg (LBF)/muscle microvascular blood flow (MBF), and muscle anabolic signaling by phosphoimmunoblotting. Plasma insulinemia and EAA/aemia were markedly greater after WP than LEAA (P Ͻ 0.001). Neither LEAA nor WP modified LBF in response to FED or FED-EX, whereas MBF increased to a similar extent in both groups only after FED-EX (P Ͻ 0.05). In response to FED, both WP and LEAA equally stimulated MPS 0 -2 h (P Ͻ 0.05), abating thereafter (0 -4 h, P Ͼ 0.05). In contrast, after FED-EX, MPS increased at 0 -2 h and remained elevated at 0 -4 h (P Ͻ 0.05) with both WP and LEAA. No anabolic signals quantifiably increased after FED, but p70 S6K1 Thr 389 increased after FED-EX (2 h, P Ͻ 0.05). APS increased similarly after WP and LEAA. Older women remain subtly responsive to nutrition Ϯ exercise. Intriguingly though, bolus WP offers no trophic advantage over LEAA. skeletal muscle; blood flow; protein synthesis; aging; amino acids; exercise ILL HEALTH ASSOCIATED WITH AGING represents a major socioeconomic burden, especially given shifting demographics toward a more aged, populous world. In particular, the loss of skeletal muscle mass associated with aging, or sarcopenia, is a major clinical issue. For instance, not only are there established links between low muscle mass and all-cause mortality per se (1), but also, lower skeletal muscle mass associated with sarcopenia leads to increased frailty, risk of falls, sedentarism, poor quality of life, and prevalence of metabolic comorbidities (17, 53).The two major extrinsic influences over muscle mass are nutrition and physical activity. For example, oral intake of protein-based foods containing essential amino acids (EAA) leads to a transient (2-3 h; see Ref.2) stimulation of muscle protein synthesis (MPS) in younger men. This brief increase in MPS above postabsorptive rates serves the purpose of replenishing protein stores lost during fasting, ensuring preservation of muscle protein mass. Similarly, physical activity is a prerequisite for maintenance of a healthy muscle mass. For example, inactivity (6, 20) causes muscle atrophy by inducing "anabo...

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Two Weeks of Reduced Activity Decreases Leg Lean Mass and Induces “Anabolic Resistance” of Myofibrillar Protein Synthesis in Healthy Elderly

Cited by 334 publications

References 34 publications

Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men

Acute cocoa flavanol supplementation improves muscle macro- and microvascular but not anabolic responses to amino acids in older men

High-intensity interval training (HIIT) increases insulin-like growth factor-I (IGF-I) in sedentary aging men but not masters’ athletes: an observational study

Intake of low-dose leucine-rich essential amino acids stimulates muscle anabolism equivalently to bolus whey protein in older women at rest and after exercise

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