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Anabolic resistance assessed by oral stable isotope ingestion following bed rest in young and older adult volunteers: Relationships with changes in muscle mass

Biolo, G. and Pišot, R. and Mazzucco, S. and Di Girolamo, F.G. and Situlin, R. and Lazzer, S. and Grassi, B. and Reggiani, C. and Passaro, A. and Rittweger, Jörn and Gasparini, M. and Simunic, B. and Narici, M. (2017) Anabolic resistance assessed by oral stable isotope ingestion following bed rest in young and older adult volunteers: Relationships with changes in muscle mass. Clinical Nutrition, 36 (5), pp. 1420-1426. Elsevier. DOI: 10.1016/j.clnu.2016.09.019 ISSN 0261-5614

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Abstract

Background & aims Aging and experimental bed rest are associated with muscle atrophy and resistance to post-prandial stimulation of protein synthesis or anabolic resistance (AR). We have used in young and older adult volunteers, during short-term bed rest, a quick and non-invasive method, based on a single oral bolus of the stable isotope L[ring-2H5]phenylalanine (D5Phe), to determine post-prandial AR, defined as ratio between irreversible hydroxylation and incorporation into body protein of ingested phenylalanine. Methods We compared in older (O, 59 ± 1 y) and young (Y, 23 ± 1 y) healthy male volunteers the effects of two-week bed rest on post-prandial protein kinetics, assessed during absorption of a standard ready-to-use oral nutritional supplement, through stable-labeled isotope amino acid D5Phe, diluted in water, given as single oral load. The metabolic fate of D5Phe is either utilization for protein synthesis or irreversible hydroxylation to L[ring-2H4]tyrosine (D4Tyr). AR was defined as ratio between the areas under the curves of D4Tyr-to-D5Phe plasma concentrations over 6 h meal absorption. To determine the relationships between AR and muscle changes following bed rest, quadriceps muscle volume (QMV) was determined by magnetic resonance imaging (MRI). Results At baseline, in pooled Y and O subjects, values of AR were inversely correlated with QMV (R = −0.75; p < 0.03). Following 2-weeks of inactivity, there were significant bed rest effects on AR (p < 0.01) and QMV (p < 0.03), as well as significant bed rest × group interaction for AR (p < 0.03; +9.2% in Y; +21.9% in O) and QMV (p < 0.05; −5.7% in Y; −%7.3 in O). In pooled subjects, the percentage delta changes in AR and QMV, induced by bed rest, were inversely correlated (R = −0.57; p < 0.05). Conclusion Bed rest-induced AR is much greater in the older than in younger adults. We have developed a new, simple, non-invasive method for the assessment of AR. The results indicate that this metabolic abnormality is a key mechanism for sarcopenia of aging and inactivity.

Item URL in elib:https://elib.dlr.de/113882/
Document Type:Article
Title:Anabolic resistance assessed by oral stable isotope ingestion following bed rest in young and older adult volunteers: Relationships with changes in muscle mass
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Biolo, G.University of TriesteUNSPECIFIED
Pišot, R.university of primorskaUNSPECIFIED
Mazzucco, S.university of triesteUNSPECIFIED
Di Girolamo, F.G.University of TriesteUNSPECIFIED
Situlin, R.University of TriesteUNSPECIFIED
Lazzer, S.university of udineUNSPECIFIED
Grassi, B.university of udine, italyUNSPECIFIED
Reggiani, C.university of padua, italyUNSPECIFIED
Passaro, A.aoes b.v.UNSPECIFIED
Rittweger, Jörnjoern.rittweger (at) dlr.dehttps://orcid.org/0000-0002-2223-8963
Gasparini, M.general hospital izola, sloveniaUNSPECIFIED
Simunic, B.university of primorskaUNSPECIFIED
Narici, M.manchester metropolitan university, u.k.UNSPECIFIED
Date:2017
Journal or Publication Title:Clinical Nutrition
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:36
DOI :10.1016/j.clnu.2016.09.019
Page Range:pp. 1420-1426
Publisher:Elsevier
ISSN:0261-5614
Status:Published
Keywords:Anabolic resistance; Isotopic tracers; Skeletal muscle; Muscle atrophy; Bed rest; Aging
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Research under Space Conditions
DLR - Research area:Raumfahrt
DLR - Program:R FR - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):R - Vorhaben Systemphysiologie
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Muscle and Bone Metabolism
Deposited By: Becker, Christine
Deposited On:05 Sep 2017 15:53
Last Modified:06 Sep 2019 15:19

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