The DOI matches its Crossref record; 11 of the 11 references it cites were found in a registry or an index.
Bed rest impairs skeletal muscle amino acid transporter expression, mTORC1 signaling, and protein synthesis in response to essential amino acids in older adults
Abstract
Skeletal muscle atrophy during bed rest is attributed, at least in part, to slower basal muscle protein synthesis (MPS). Essential amino acids (EAA) stimulate mammalian target of rapamycin (mTORC1) signaling, amino acid transporter expression, and MPS and are necessary for muscle mass maintenance, but there are no data on the effect of inactivity on this anabolic mechanism. We hypothesized that bed rest decreases muscle mass in older adults by blunting the EAA stimulation of MPS through reduced mTORC1 signaling and amino acid transporter expression in older adults. Six healthy older adults (67 ± 2 yr) participated in a 7-day bed rest study. We used stable isotope tracers, Western blotting, and real-time qPCR to determine the effect of bed rest on MPS, muscle mTORC1 signaling, and amino acid transporter expression and content in the postabsorptive state and after acute EAA ingestion. Bed rest decreased leg lean mass by ∼4% ( P < 0.05) and increased postabsorptive mTOR protein ( P < 0.05) levels while postabsorptive MPS was unchanged ( P > 0.05). Before bed rest acute EAA ingestion increased MPS, mTOR (Ser 2448 ), S6 kinase 1 (Thr 389 , Thr 421 /Ser 424 ), and ribosomal protein S6 (Ser 240/244 ) phosphorylation, activating transcription factor 4, L-type amino acid transporter 1 and sodium-coupled amino acid transporter 2 protein content ( P < 0.05). However, bed rest blunted the EAA-induced increase in MPS, mTORC1 signaling, and amino acid transporter protein content. We conclude that bed rest in older adults significantly attenuated the EAA-induced increase in MPS with a mechanism involving reduced mTORC1 signaling and amino acid transporter protein content. Together, our data suggest that a blunted EAA stimulation of MPS may contribute to muscle loss with inactivity in older persons.
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“while studies in Master athletes are lacking, the observation that inactivity can reduce amino acid transporter expression [55], whereas activity can increase its expression in young and older adults could collectively suggest the presence of sufficient amino acid transporters would not represent a rate-controlling step for post-exercise anabolism in concurrently training Master athletes.”
From Protein Requirements for Master Athletes: Just Older Versions of Their Younger Selves (2021) · cites this paper as [55]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cites
Effect of 10 Days of Bed Rest on Skeletal Muscle in Healthy Older Adults
Kortebein, P., Ferrando, A., Lombeida, J., Wolfe, R., & Evans, W. J. (2007) · JAMA · doi:10.1001/jama.297.16.1772-b · Cited by 933
Katsanos, C. S., Kobayashi, H., Sheffield-Moore, M., Aarsland, A., & Wolfe, R. R. (2006) · American Journal of Physiology-Endocrinology and Metabolism · doi:10.1152/ajpendo.00488.2005 · Cited by 923
Dreyer, H. C., Fujita, S., Cadenas, J. G., Chinkes, D. L., Volpi, E., & Rasmussen, B. B. (2006) · The Journal of Physiology · doi:10.1113/jphysiol.2006.113175 · Cited by 570 · cited 3×
“Muscle tissue samples (biopsies 1–4) were ground, and intracellular free amino acids and muscle proteins were extracted as previously described (9).”
BackgroundMethodSelf-citationVolpi, E., Mittendorfer, B., Rasmussen, B. B., & Wolfe, R. R. (2000) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jcem.85.12.7021 · Cited by 464
Self-citationGuillet, C., Prod'homme, M., Balage, M., Gachon, P., Giraudet, C., Morin, L., Grizard, J., & Boirie, Y. (2004) · The FASEB Journal · doi:10.1096/fj.03-1341fje · Cited by 412
Nutrient signalling in the regulation of human muscle protein synthesis
Fujita, S., Dreyer, H. C., Drummond, M. J., Glynn, E. L., Cadenas, J. G., Yoshizawa, F., Volpi, E., & Rasmussen, B. B. (2007) · The Journal of Physiology · doi:10.1113/jphysiol.2007.134593 · Cited by 339
Self-citationPaddon-Jones, D., Sheffield-Moore, M., Urban, R. J., Sanford, A. P., Aarsland, A., Wolfe, R. R., & Ferrando, A. A. (2004) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2003-032159 · Cited by 338
Self-citationBurd, N. A., West, D. W. D., Moore, D. R., Atherton, P. J., Staples, A. W., Prior, T., Tang, J. E., Rennie, M. J., Baker, S. K., & Phillips, S. M. (2011) · The Journal of Nutrition · doi:10.3945/jn.110.135038 · Cited by 325
Dickinson, J. M., Fry, C. S., Drummond, M. J., Gundermann, D. M., Walker, D. K., Glynn, E. L., Timmerman, K. L., Dhanani, S., Volpi, E., & Rasmussen, B. B. (2011) · The Journal of Nutrition · doi:10.3945/jn.111.139485 · Cited by 282
Self-citationRegulation of placental amino acid transporter activity by mammalian target of rapamycin
Roos, S., Kanai, Y., Prasad, P. D., Powell, T. L., & Jansson, T. (2009) · American Journal of Physiology-Cell Physiology · doi:10.1152/ajpcell.00330.2008 · Cited by 150
The Deleterious Effects of Bed Rest Among Community-Living Older Persons
Gill, T. M., Allore, H., & Guo, Z. (2004) · The Journals of Gerontology Series A: Biological Sciences and Medical Sciences · doi:10.1093/gerona/59.7.m755 · Cited by 108
Research works printed but not linked: 37
- 10.1074/jbc.M610510200 · DOI
- 10.1152/ajpendo.00330.2009 · DOI · Paper page
- 10.1111/j.1748-1716.1993.tb09573.x · DOI · Paper page
- 10.1002/rcm.1290060704 · DOI
- 10.1111/j.1532-5415.2006.00997.x · DOI
- 10.1113/jphysiol.2007.142828 · DOI · Paper page
- 10.1152/japplphysiol.91397.2008 · DOI · Paper page
- 10.1152/japplphysiol.00021.2008 · DOI · Paper page
- 10.1152/japplphysiol.01408.2010 · DOI · Paper page
- 10.1152/ajpendo.00690.2009 · DOI
- 10.1152/ajpendo.1996.270.4.E627 · DOI · Paper page
- 10.1001/archinternmed.2010.422 · DOI
- 10.1042/cs0720503 · DOI
- 10.1113/jphysiol.2008.160333 · DOI · Paper page
- 10.1139/H09-137 · DOI
- 10.3945/jn.110.127647 · DOI · Paper page
- 10.1152/japplphysiol.00110.2009 · DOI
- 10.1152/japplphysiol.00637.2010 · DOI · Paper page
- 10.1096/fj.04-2284fje · DOI
- 10.1074/jbc.M108609200 · DOI
- 10.1093/ajcn/82.5.1065 · DOI · Paper page
- 10.1152/japplphysiol.00221.2002 · DOI · Paper page
- 10.1006/meth.2001.1262 · DOI · Paper page
- 10.1074/jbc.M801331200 · DOI
- 10.1016/j.cell.2008.11.044 · DOI · Paper page
- 10.1128/MCB.22.15.5575-5584.2002 · DOI · Paper page
- Peyrollier K, 2000, Biochem J, 350, 361, 10.1042/bj3500361 · DOI
- Pinilla J, 2011, Front Biosci, 3, 1289
- 10.1152/japplphysiol.00444.2010 · DOI
- 10.1152/ajpcell.00191.2009 · DOI
- 10.1152/japplphysiol.00290.2009 · DOI · Paper page
- 10.1093/ajcn/86.2.451 · DOI · Paper page
- 10.1152/japplphysiol.91137.2008 · DOI · Paper page
- 10.1016/j.jada.2009.06.369 · DOI · Paper page
- 10.1152/japplphysiol.90558.2008 · DOI
- Volpi E, 2000, J Cclin Endocrinol Metab, 85, 4481
- Wolfe RR, 2005, Isotope Tracers in Metabolic Research Principles and Practice of Kinetic Analysis
Cited by
Moore, D. R., Churchward-Venne, T. A., Witard, O., Breen, L., Burd, N. A., Tipton, K. D., & Phillips, S. M. (2015) · The Journals of Gerontology: Series A · doi:10.1093/gerona/glu103 · Cited by 770
Skeletal muscle atrophy during short-term disuse: Implications for age-related sarcopenia
Wall, B. T., Dirks, M. L., & van Loon, L. J. C. (2013) · Ageing Research Reviews · doi:10.1016/j.arr.2013.07.003 · Cited by 400
Breen, L., Stokes, K. A., Churchward-Venne, T. A., Moore, D. R., Baker, S. K., Smith, K., Atherton, P. J., & Phillips, S. M. (2013) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2013-1502 · Cited by 395
Anabolic Resistance of Muscle Protein Synthesis with Aging
Burd, N. A., Gorissen, S. H., & van Loon, L. J. C. (2013) · Exercise and Sport Sciences Reviews · doi:10.1097/jes.0b013e318292f3d5 · Cited by 384
Aging is accompanied by a blunted muscle protein synthetic response to protein ingestion
Wall, B. T., Gorissen, S. H., Pennings, B., Koopman, R., Groen, B. B. L., Verdijk, L. B., & van Loon, L. J. C. (2015) · PLOS ONE · doi:10.1371/journal.pone.0140903 · Cited by 352
Metadata
- Authors
- Drummond, M. J., Dickinson, J. M., Fry, C. S., Walker, D. K., Gundermann, D. M., Reidy, P. T., Timmerman, K. L., Markofski, M. M., Paddon-Jones, D., Rasmussen, B. B., & Volpi, E.
- Venue
- American Journal of Physiology-Endocrinology and Metabolism
- Publisher
- American Physiological Society
- Published
- 2012-05-01
- Volume
- 302
- Issue
- 9
- Pages
- E1113-E1122
- ISSN
- 0193-1849
- 1522-1555
- Cited by
- 197
- References
- 11
- Language
- en
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
Data sources
Bibliographic data: Semantic Scholar, OpenAlex, Crossref.
Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.
