scholarly journals Improved recovery from skeletal muscle damage is largely unexplained by myofibrillar protein synthesis or inflammatory and regenerative gene expression pathways

2020 ◽  
Author(s):  
George Frederick Pavis ◽  
Tom SO Jameson ◽  
Marlou L. Dirks ◽  
Benjamin P. Lee ◽  
Doaa Reda Abdelrahman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Damage ◽  
Muscle Function ◽  
Nutritional Intervention ◽  
Myofibrillar Protein ◽  
Skeletal Muscle Damage ◽  
Amino Acid Availability ◽  
Expression Pathways ◽  
Myofibrillar Protein Synthesis

The contribution of myofibrillar protein synthesis (MyoPS) to recovery from skeletal muscle damage in humans is unknown. Recreationally active males and females consumed a daily protein-polyphenol beverage targeted at increasing amino acid availability and reducing inflammation (PPB; n=9), both known to affect MyoPS, or an isocaloric placebo (PLA; n=9) during 168 h of recovery from 300 maximal unilateral eccentric contractions (EE). Muscle function was assessed daily. Muscle biopsies were collected 24, 27, 36, 72 and 168 h for MyoPS measurements using 2H2O and expression of 224 genes using RT-qPCR and pathway analysis. PPB improved recovery of muscle function, which was impaired for five days following EE in PLA (interaction; P<0.05). Acute postprandial MyoPS rates were unaffected by nutritional intervention (24-27 h). EE increased overnight (27-36 h) MyoPS versus control leg (PLA: 33±19%; PPB: 79±25%; leg P<0.01), and PPB tended to increase this further (interaction P=0.06). Daily MyoPS rates were greater with PPB between 72-168 h after EE, albeit after function had recovered. Inflammatory and regenerative signaling pathways were dramatically upregulated and clustered following EE but were unaffected by nutritional intervention. These results suggest that accelerated recovery from EE is not explained by elevated MyoPS or suppression of inflammation.

scholarly journals Skeletal muscle IL-15/IL-15Rα and myofibrillar protein synthesis after resistance exercise

2017 ◽  
Vol 28 (1) ◽  
pp. 116-125 ◽  
Author(s):  
A. Pérez-López ◽  
J. McKendry ◽  
M. Martin-Rincon ◽  
D. Morales-Alamo ◽  
B. Pérez-Köhler ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Myofibrillar Protein ◽  
Myofibrillar Protein Synthesis

scholarly journals Leucine-enriched amino acids maintain peripheral mTOR-Rheb localization independent of myofibrillar protein synthesis and mTORC1 signaling postexercise

2020 ◽  
Vol 129 (1) ◽  
pp. 133-143 ◽  
Author(s):  
Sarkis J. Hannaian ◽  
Nathan Hodson ◽  
Sidney Abou Sawan ◽  
Michael Mazzulla ◽  
Hiroyuki Kato ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Protein Interactions ◽  
Human Skeletal Muscle ◽  
Myofibrillar Protein ◽  
Protein Protein Interactions ◽  
Peripheral Location ◽  
Mtorc1 Signaling ◽  
Myofibrillar Protein Synthesis

This is the first study to investigate whether postexercise leucine-enriched amino acid (LEAA) ingestion elevates mTORC1 translocation and protein-protein interactions in human skeletal muscle. Here, we observed that although LEAA ingestion did not further elevate postexercise MyoPS or mTORC1 signaling compared with placebo, mTORC1 peripheral location and interaction with Rheb were maintained. This may serve to “prime” mTORC1 for subsequent anabolic stimuli.

Citrulline does not enhance blood flow, microvascular circulation, or myofibrillar protein synthesis in elderly men at rest or following exercise

2014 ◽  
Vol 307 (1) ◽  
pp. E71-E83 ◽  
Author(s):  
Tyler A. Churchward-Venne ◽  
Lisa M. Cotie ◽  
Maureen J. MacDonald ◽  
Cameron J. Mitchell ◽  
Todd Prior ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Blood Flow ◽  
Protein Synthesis ◽  
Whey Protein ◽  
Myofibrillar Protein ◽  
Microvascular Perfusion ◽  
Anabolic Resistance ◽  
Nonessential Amino Acids ◽  
Myofibrillar Protein Synthesis

Aging is associated with anabolic resistance, a reduced sensitivity of myofibrillar protein synthesis (MPS) to postprandial hyperaminoacidemia, particularly with low protein doses. Impairments in postprandial skeletal muscle blood flow and/or microvascular perfusion with hyperaminoacidemia and hyperinsulinemia may contribute to anabolic resistance. We examined whether providing citrulline, a precursor for arginine and nitric oxide synthesis, would increase arterial blood flow, skeletal muscle microvascular perfusion, MPS, and signaling through mTORC1. Twenty-one elderly males (65–80 yr) completed acute unilateral resistance exercise prior to being assigned to ingest a high dose (45 g) of whey protein (WHEY) or a low dose (15 g) of whey protein with 10 g of citrulline (WHEY + CIT) or with 10 g of nonessential amino acids (WHEY + NEAA). A primed, continuous infusion of l-[ ring-13C6] phenylalanine with serial muscle biopsies was used to measure MPS and protein phosphorylation, whereas ultrasound was used to measure microvascular circulation under basal and postprandial conditions in both a rested (FED) and exercised (EX-FED) leg. Argininemia was greater in WHEY + CIT vs. WHEY and WHEY + NEAA from 30 to 300 min postexercise ( P < 0.001), but there were no treatment differences in blood flow or microvascular perfusion (all P > 0.05). Phosphorylation of p70S6K-Thr389was greater in WHEY vs. WHEY + NEAA ( P = 0.02). Postprandial MPS was greater in WHEY vs. WHEY + CIT and WHEY + NEAA under both FED (WHEY: ∼128%; WHEY + CIT: ∼56%; WHEY + NEAA: ∼38%) and EX-FED (WHEY: ∼251%; WHEY + CIT: ∼124%; WHEY + NEAA: ∼108%) conditions ( P = 0.003). Citrulline coingestion with a low quantity of protein was ineffective in augmenting the anabolic properties of protein compared with nonessential amino acids.

scholarly journals Growth hormone stimulates the collagen synthesis in human tendon and skeletal muscle without affecting myofibrillar protein synthesis

2010 ◽  
Vol 588 (2) ◽  
pp. 341-351 ◽  
Author(s):  
Simon Doessing ◽  
Katja M. Heinemeier ◽  
Lars Holm ◽  
Abigail L. Mackey ◽  
Peter Schjerling ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Collagen Synthesis ◽  
Myofibrillar Protein ◽  
Human Tendon ◽  
Myofibrillar Protein Synthesis

scholarly journals Daily Myofibrillar Protein Synthesis Rates in Response to Low- and High-Frequency Resistance Exercise Training in Healthy, Young Men

2020 ◽  
pp. 1-8
Author(s):  
Brandon J. Shad ◽  
Janice L. Thompson ◽  
James Mckendry ◽  
Andrew M. Holwerda ◽  
Yasir S. Elhassan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Exercise Training ◽  
Resistance Exercise ◽  
High Frequency ◽  
Young Men ◽  
Myofibrillar Protein ◽  
Resistance Exercise Training ◽  
Repetition Maximum ◽  
Myofibrillar Protein Synthesis

The impact of resistance exercise frequency on muscle protein synthesis rates remains unknown. The aim of this study was to compare daily myofibrillar protein synthesis rates over a 7-day period of low-frequency (LF) versus high-frequency (HF) resistance exercise training. Nine young men (21 ± 2 years) completed a 7-day period of habitual physical activity (BASAL). This was followed by a 7-day exercise period of volume-matched, LF (10 × 10 repetitions at 70% one-repetition maximum, once per week) or HF (2 × 10 repetitions at ∼70% one-repetition maximum, five times per week) resistance exercise training. The participants had one leg randomly allocated to LF and the other to HF. Skeletal muscle biopsies and daily saliva samples were collected to determine myofibrillar protein synthesis rates using 2H2O, with intracellular signaling determined using Western blotting. The myofibrillar protein synthesis rates did not differ between the LF (1.46 ± 0.26%/day) and HF (1.48 ± 0.33%/day) conditions over the 7-day exercise training period (p > .05). There were no significant differences between the LF and HF conditions over the first 2 days (1.45 ± 0.41%/day vs. 1.25 ± 0.46%/day) or last 5 days (1.47 ± 0.30%/day vs. 1.50 ± 0.41%/day) of the exercise training period (p > .05). Daily myofibrillar protein synthesis rates were not different from BASAL at any time point during LF or HF (p > .05). The phosphorylation status and total protein content of selected proteins implicated in skeletal muscle ribosomal biogenesis were not different between conditions (p > .05). Under the conditions of the present study, resistance exercise training frequency did not modulate daily myofibrillar protein synthesis rates in young men.

Whey and casein labeled with l-[1-13C]leucine and muscle protein synthesis: effect of resistance exercise and protein ingestion

2011 ◽  
Vol 300 (1) ◽  
pp. E231-E242 ◽  
Author(s):  
Søren Reitelseder ◽  
Jakob Agergaard ◽  
Simon Doessing ◽  
Ida C. Helmark ◽  
Peter Lund ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Myofibrillar Protein ◽  
Western Blots ◽  
Amino Acid Availability ◽  
Amino Acid Concentrations ◽  
Myofibrillar Protein Synthesis

Muscle protein turnover following resistance exercise and amino acid availability are relatively well described. By contrast, the beneficial effects of different sources of intact proteins in relation to exercise need further investigation. Our objective was to compare muscle anabolic responses to a single bolus intake of whey or casein after performance of heavy resistance exercise. Young male individuals were randomly assigned to participate in two protein trials ( n = 9) or one control trial ( n = 8). Infusion of l-[1-13C]leucine was carried out, and either whey, casein (0.3 g/kg lean body mass), or a noncaloric control drink was ingested immediately after exercise. l-[1-13C]leucine-labeled whey and casein were used while muscle protein synthesis (MPS) was assessed. Blood and muscle tissue samples were collected to measure systemic hormone and amino acid concentrations, tracer enrichments, and myofibrillar protein synthesis. Western blots were used to investigate the Akt signaling pathway. Plasma insulin and branched-chain amino acid concentrations increased to a greater extent after ingestion of whey compared with casein. Myofibrillar protein synthesis was equally increased 1–6 h postexercise after whey and casein intake, both of which were higher compared with control ( P < 0.05). Phosphorylation of Akt and p70S6K was increased after exercise and protein intake ( P < 0.05), but no differences were observed between the types of protein except for total 4E-BP1, which was higher after whey intake than after casein intake ( P < 0.05). In conclusion, whey and casein intake immediately after resistance exercise results in an overall equal MPS response despite temporal differences in insulin and amino acid concentrations and 4E-BP1.

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