Corrigendum: Integrated Myofibrillar Protein Synthesis in Recovery From Unaccustomed and Accustomed Resistance Exercise With and Without Multi-ingredient Supplementation in Overweight Older Men.

[This corrects the article DOI: 10.3389/fnut.2019.00040.].

Integrated Myofibrillar Protein Synthesis in Recovery From Unaccustomed and Accustomed Resistance Exercise With and Without Multi-ingredient Supplementation in Overweight Older Men.

Background: We previously showed that daily consumption of a multi-ingredient nutritional supplement increased lean mass in older men, but did not enhance lean tissue gains during a high-intensity interval training (HIIT) plus resistance exercise training (RET) program. Here, we aimed to determine whether these divergent observations aligned with the myofibrillar protein synthesis (MyoPS) response to acute unaccustomed and accustomed resistance exercise. Methods: A sub-sample of our participants were randomly allocated (n = 15; age: 72 ± 7 years; BMI: 26.9 ± 3.1 kg/m2 [mean ± SD]) to ingest an experimental supplement (SUPP, n = 8: containing whey protein, creatine, vitamin D, and n-3 PUFA) or control beverage (CON, n = 7: 22 g maltodextrin) twice per day for 21 weeks. After 7 weeks of consuming the beverage alone (Phase 1: SUPP/CON only), subjects completed 12 weeks of RET (twice per week) + HIIT (once per week) (Phase 2: SUPP/CON + EX). Orally administered deuterated water was used to measure integrated rates of MyoPS over 48 h following a single session of resistance exercise pre- (unaccustomed) and post-training (accustomed). Results: Following an acute bout of accustomed resistance exercise, 0-24 h MyoPS was 30% higher than rest in the SUPP group (effect size: 0.86); however, in the CON group, 0-24 h MyoPS was 0% higher than rest (effect size: 0.04). Nonetheless, no within or between group changes in MyoPS were statistically significant. When collapsed across group, rates of MyoPS in recovery from acute unaccustomed resistance exercise were positively correlated with training-induced gains in whole body lean mass (r = 0.63, p = 0.01). Conclusion: There were no significant between-group differences in MyoPS pre- or post-training. Integrated rates of MyoPS post-acute exercise in the untrained state were positively correlated with training-induced gains in whole body lean mass. Our finding that supplementation did not alter 0-48 h MyoPS following 12 weeks of training suggests a possible adaptive response to longer-term increased protein intake and warrants further investigation. This study was registered at ClinicalTrials.gov. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02281331.

Contraction mode and whey protein intake affect the synthesis rate of intramuscular connective tissue.

INTRODUCTION: In this study we investigated the impact of whey protein hydrolysate and maltodextrin (WPH) intake on intramuscular connective tissue (IMCT) protein fractional synthesis rate (FSR) after maximal shortening and lengthening contractions. METHODS: Twenty young men were randomized to receive either WPH or maltodextrin [carbohydrate (CHO)] immediately after completion of unilateral shortening and lengthening knee extensions. Ring-13 C6 -phenylalanine was infused, and muscle biopsies were obtained. IMCT protein FSR was measured at 1-5, as well as 1-3 and 3-5 hours after contractions and nutrient intake. RESULTS: During the 1-3-hour recovery, lengthening contractions resulted in a higher FSR than shortening contractions (P < 0.01), independent of supplementation type and, during the 3-5-hour recovery, WPH had a higher FSR than CHO (P < 0.05), independent of prior contraction mode. CONCLUSIONS: The later appearance of a stimulating effect of WPH on the IMCT FSR after strenuous muscle contractions lends support to its ability to promote recovery of the muscle connective tissue matrix after exercise. Muscle Nerve 55: 128-130, 2017.

Tumor necrosis factor-? regulates the effect of glutamine on protein synthesis in rats' skeletal muscle / 医学研究生学报

Objective:To find the regulations of glutamine(Gln) metabolism by tumor necrosis factor-?(TNF-?).Methods:Thirty male SD rats were assigned into three groups: A(total parenteral nutrition,TPN),B(TPN+Gln),C(TPN+ TNF-?+Gln).Besides all rats were supported by isonitrogenous and isocaloric TPN solutions for 3 days,rats in group B were supplied with Gln(in the form of alanylglutamine) for 3 days at the rate of 0.3 g/(kg?d),rats in group C were infused intravenously with TNF-? at the rate of 5 ?g/(kg?h) within the last 24 hours and also supplemented with Gln for three days at the same rate as in group B.At the last 0.5 hour,all animals were mainlined with \leucine at the dosage of 1.0 mmol/kg.TNF-? levels in plasma,concentrations of Gln in plasma and skeletal muscle were measured as the experiment ended after 72 hours,and the fractional synthesis rate(FSR) were also assessed.Results:The Gln concentrations in plasma and skeletal muscle increased markedly from group A,B to C.The levels of FSR decreased remarkably along with the sequence from group B,C to A.The statistical differences were significant(P