Short-term muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates

Short-term muscle disuse has been reported to lower both postabsorptive and postprandial myofibrillar protein synthesis rates. This study assessed the impact of disuse on daily myofibrillar protein synthesis rates following short-term (2 and 7 days) muscle disuse under free living conditions. Thirteen healthy young men (age: 20 ± 1 yr; BMI: 23 ± 1 kg/m−2) underwent 7 days of unilateral leg immobilization via a knee brace, with the nonimmobilized leg acting as a control. Four days before immobilization participants ingested 400 mL of 70% deuterated water, with 50-mL doses consumed daily thereafter. Upper leg bilateral MRI scans and muscle biopsies were collected before and after 2 and 7 days of immobilization to determine quadriceps volume and daily myofibrillar protein synthesis rates. Immobilization reduced quadriceps volume in the immobilized leg by 1.7 ± 0.3 and 6.7 ± 0.6% after 2 and 7 days, respectively, with no changes in the control leg. Over the 1-wk immobilization period, myofibrillar protein synthesis rates were 36 ± 4% lower in the immobilized (0.81 ± 0.04%/day) compared with the control (1.26 ± 0.04%/day) leg ( P < 0.001). Myofibrillar protein synthesis rates in the control leg did not change over time ( P = 0.775), but in the immobilized leg they were numerically lower during the 0- to 2-day period (16 ± 6%, 1.11 ± 0.09%/day, P = 0.153) and were significantly lower during the 2- to 7-day period (44 ± 5%, 0.70 ± 0.06%/day, P < 0.001) when compared with the control leg. We conclude that 1 wk of muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates in healthy young men.

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Short-term muscle disuse lowers myofibrillar protein synthesis rates and induces anabolic resistance to protein ingestion

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00227.2015 ◽

2016 ◽

Vol 310 (2) ◽

pp. E137-E147 ◽

Cited By ~ 57

Author(s):

Benjamin T. Wall ◽

Marlou L. Dirks ◽

Tim Snijders ◽

Jan-Willem van Dijk ◽

Mario Fritsch ◽

...

Keyword(s):

Protein Synthesis ◽

Muscle Protein ◽

Myofibrillar Protein ◽

Disuse Atrophy ◽

Short Term ◽

Anabolic Resistance ◽

Muscle Disuse ◽

Protein Ingestion ◽

The Impact ◽

Myofibrillar Protein Synthesis

Disuse leads to rapid loss of skeletal muscle mass and function. It has been hypothesized that short successive periods of muscle disuse throughout the lifespan play an important role in the development of sarcopenia. The physiological mechanisms underlying short-term muscle disuse atrophy remain to be elucidated. We assessed the impact of 5 days of muscle disuse on postabsorptive and postprandial myofibrillar protein synthesis rates in humans. Twelve healthy young (22 ± 1 yr) men underwent a 5-day period of one-legged knee immobilization (full leg cast). Quadriceps cross-sectional area (CSA) of both legs was assessed before and after immobilization. Continuous infusions of l-[ ring-2H5]phenylalanine and l-[1-13C]leucine were combined with the ingestion of a 25-g bolus of intrinsically l-[1-13C]phenylalanine- and l-[1-13C]leucine-labeled dietary protein to assess myofibrillar muscle protein fractional synthetic rates in the immobilized and nonimmobilized control leg. Immobilization led to a 3.9 ± 0.6% decrease in quadriceps muscle CSA of the immobilized leg. Based on the l-[ ring-2H5]phenylalanine tracer, immobilization reduced postabsorptive myofibrillar protein synthesis rates by 41 ± 13% (0.015 ± 0.002 vs. 0.032 ± 0.005%/h, P < 0.01) and postprandial myofibrillar protein synthesis rates by 53 ± 4% (0.020 ± 0.002 vs. 0.044 ± 0.003%/h, P < 0.01). Comparable results were found using the l-[1-13C]leucine tracer. Following protein ingestion, myofibrillar protein bound l-[1-13C]phenylalanine enrichments were 53 ± 18% lower in the immobilized compared with the control leg (0.007 ± 0.002 and 0.015 ± 0.002 mole% excess, respectively, P < 0.05). We conclude that 5 days of muscle disuse substantially lowers postabsorptive myofibrillar protein synthesis rates and induces anabolic resistance to protein ingestion.

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Impact of Short-term Sedentariness on Week-to-Week Myofibrillar Protein Synthesis Rates in Physically Active Young Men

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000536301.79919.83 ◽

2018 ◽

Vol 50 (5S) ◽

pp. 370

Author(s):

Brandon J. Shad ◽

Andrew M. Holwerda ◽

Yasir S. Elhassan ◽

Luc J.C. van Loon ◽

Janice L. Thompson ◽

...

Keyword(s):

Protein Synthesis ◽

Young Men ◽

Myofibrillar Protein ◽

Short Term ◽

Physically Active ◽

Myofibrillar Protein Synthesis

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Presleep dietary protein-derived amino acids are incorporated in myofibrillar protein during postexercise overnight recovery

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00273.2016 ◽

2018 ◽

Vol 314 (5) ◽

pp. E457-E467 ◽

Cited By ~ 33

Author(s):

Jorn Trommelen ◽

Imre W. K. Kouw ◽

Andrew M. Holwerda ◽

Tim Snijders ◽

Shona L. Halson ◽

...

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Dietary Protein ◽

Myofibrillar Protein ◽

Whole Body ◽

Body Protein ◽

Protein Ingestion ◽

Casein Protein ◽

The Impact ◽

Myofibrillar Protein Synthesis

The purpose of this study was to determine the impact of ingesting 30 g casein protein with and without 2 g free leucine before sleep on myofibrillar protein synthesis rates during postexercise overnight recovery. Thirty-six healthy young men performed a single bout of resistance-type exercise in the evening (1945) after a full day of dietary standardization. Thirty minutes before sleep (2330), subjects ingested 30 g intrinsically l-[1-13C]phenylalanine-labeled protein with (PRO+leu, n = 12) or without (PRO, n = 12) 2 g free leucine, or a noncaloric placebo (PLA, n = 12). Continuous intravenous l-[ ring-2H5]phenylalanine, l-[1-13C]leucine, and l-[ ring-2H2]tyrosine infusions were applied. Blood and muscle tissue samples were collected to assess whole body protein net balance, myofibrillar protein synthesis rates, and overnight incorporation of dietary protein-derived amino acids into myofibrillar protein. Protein ingestion before sleep improved overnight whole body protein net balance ( P < 0.001). Myofibrillar protein synthesis rates did not differ significantly between treatments as assessed by l-[ ring-2H5]phenylalanine (0.057 ± 0.002, 0.055 ± 0.002, and 0.055 ± 0.004%/h for PLA, PRO, and PRO+leu, respectively; means ± SE; P = 0.850) or l-[1-13C]leucine (0.080 ± 0.004, 0.073 ± 0.004, and 0.083 ± 0.006%/h, respectively; P = 0.328). Myofibrillar l-[1-13C]phenylalanine enrichments increased following protein ingestion but did not differ between the PRO and PRO+leu treatments. In conclusion, protein ingestion before sleep improves whole body protein net balance and provides amino acids that are incorporated into myofibrillar protein during sleep. However, the ingestion of 30 g casein protein with or without additional free leucine before sleep does not increase muscle protein synthesis rates during postexercise overnight recovery.

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Dietary protein intake does not modulate daily myofibrillar protein synthesis rates or loss of muscle mass and function during short-term immobilization in young men: a randomized controlled trial

American Journal of Clinical Nutrition ◽

10.1093/ajcn/nqaa136 ◽

2020 ◽

Cited By ~ 3

Author(s):

Sean Paul Kilroe ◽

Jonathan Fulford ◽

Sarah Jackman ◽

Andrew Holwerda ◽

Annemie Gijsen ◽

...

Keyword(s):

Muscle Mass ◽

Dietary Protein ◽

Protein Intake ◽

Quadriceps Muscle ◽

Myofibrillar Protein ◽

Muscle Volume ◽

Dietary Protein Intake ◽

Short Term ◽

Muscle Disuse ◽

Myofibrillar Protein Synthesis

ABSTRACT Background Short-term (<1 wk) muscle disuse lowers daily myofibrillar protein synthesis (MyoPS) rates resulting in muscle mass loss. The understanding of how daily dietary protein intake influences such muscle deconditioning requires further investigation. Objectives To assess the influence of graded dietary protein intakes on daily MyoPS rates and the loss of muscle mass during 3 d of disuse. Methods Thirty-three healthy young men (aged 22 ± 1 y; BMI = 23 ± 1 kg/m2) initially consumed the same standardized diet for 5 d, providing 1.6 g protein/kg body mass/d. Thereafter, participants underwent a 3-d period of unilateral leg immobilization during which they were randomly assigned to 1 of 3 eucaloric diets containing relatively high, low, or no protein (HIGH: 1.6, LOW: 0.5, NO: 0.15 g protein/kg/d; n = 11 per group). One day prior to immobilization participants ingested 400 mL deuterated water (D2O) with 50-mL doses consumed daily thereafter. Prior to and immediately after immobilization upper leg bilateral MRI scans and vastus lateralis muscle biopsies were performed to measure quadriceps muscle volume and daily MyoPS rates, respectively. Results Quadriceps muscle volume of the control legs remained unchanged throughout the experiment (P > 0.05). Immobilization led to 2.3 ± 0.4%, 2.7 ± 0.2%, and 2.0 ± 0.4% decreases in quadriceps muscle volume (P < 0.05) of the immobilized leg in the HIGH, LOW, and NO groups (P < 0.05), respectively, with no significant differences between groups (P > 0.05). D2O ingestion resulted in comparable plasma free [2H]-alanine enrichments during immobilization (∼2.5 mole percentage excess) across groups (P > 0.05). Daily MyoPS rates during immobilization were 30 ± 2% (HIGH), 26 ± 3% (LOW), and 27 ± 2% (NO) lower in the immobilized compared with the control leg, with no significant differences between groups (P > 0.05). Conclusions Three days of muscle disuse induces considerable declines in muscle mass and daily MyoPS rates. However, daily protein intake does not modulate any of these muscle deconditioning responses. Clinical trial registry number: NCT03797781

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Correction: Acute Post-Exercise Myofibrillar Protein Synthesis Is Not Correlated with Resistance Training-Induced Muscle Hypertrophy in Young Men

PLoS ONE ◽

10.1371/journal.pone.0098731 ◽

2014 ◽

Vol 9 (5) ◽

pp. e98731

Author(s):

Keyword(s):

Protein Synthesis ◽

Resistance Training ◽

Muscle Hypertrophy ◽

Young Men ◽

Myofibrillar Protein ◽

Post Exercise ◽

Myofibrillar Protein Synthesis

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Damaging eccentric exercise attenuates disuse induced declines in daily myofibrillar protein synthesis and transiently prevents muscle atrophy in healthy men.

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00294.2021 ◽

2021 ◽

Author(s):

Tom S. O. Jameson ◽

Sean P Kilroe ◽

Jonathan Fulford ◽

Doaa Reda Abdelrahman ◽

Andrew John Murton ◽

...

Keyword(s):

Protein Synthesis ◽

Eccentric Exercise ◽

Vastus Lateralis ◽

Quadriceps Muscle ◽

Quadriceps Strength ◽

Myofibrillar Protein ◽

Muscle Volume ◽

Vastus Lateralis Muscle ◽

Deuterated Water ◽

Myofibrillar Protein Synthesis

Introduction: Short-term disuse leads to muscle loss driven by lowered daily myofibrillar protein synthesis (MyoPS). However, disuse commonly results from muscle damage, and its influence on muscle deconditioning during disuse is unknown. Methods: 21 males (20±1 y, BMI=24±1 kg·m-2 (±SEM)) underwent 7 days of unilateral leg immobilization immediately preceded by 300 bilateral, maximal, muscle-damaging eccentric quadriceps contractions (DAM; n=10) or no exercise (CON; n=11). Participants ingested deuterated water and underwent temporal bilateral thigh MRI scans and vastus lateralis muscle biopsies of immobilized (IMM) and non-immobilized (N-IMM) legs. Results: N-IMM quadriceps muscle volume remained unchanged throughout in both groups. IMM quadriceps muscle volume declined after 2 days by 1.7±0.5% in CON (P=0.031; and by 1.3±0.6% when corrected to N-IMM; P=0.06) but did not change in DAM, and declined equivalently in CON (by 6.4±1.1% [5.0±1.6% when corrected to N-IMM]) and DAM (by 2.6±1.8% [4.0±1.9% when corrected to N-IMM]) after 7 days. Immobilization began to decrease MyoPS compared with N-IMM in both groups after 2 days (P=0.109), albeit with higher MyoPS rates in DAM compared with CON (P=0.035). Frank suppression of MyoPS was observed between days 2-7 in CON (IMM=1.04±0.12, N-IMM=1.86±0.10%·d-1; P=0.002) but not DAM (IMM=1.49±0.29, N-IMM=1.90±0.30%·d-1; P>0.05). Declines in MyoPS and quadriceps volume after 7 days correlated positively in CON (R2=0.403; P=0.035) but negatively in DAM (R2=0.483; P=0.037). Quadriceps strength declined following immobilization in both groups, but to a greater extent in DAM. Conclusion: Prior muscle damaging eccentric exercise increases MyoPS and prevents loss of quadriceps muscle volume after 2 (but not 7) days of disuse.

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