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Publications (10 of 65) Show all publications
Holm, L., Dideriksen, K., Nielsen, R. H., Doessing, S., Bechshoeft, R. L., Højfeldt, G., . . . van Hall, G. (2019). An exploration of the methods to determine the protein-specific synthesis and breakdown rates in vivo in humans.. Physiological Reports, 7(17), Article ID e14143.
Open this publication in new window or tab >>An exploration of the methods to determine the protein-specific synthesis and breakdown rates in vivo in humans.
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2019 (English)In: Physiological Reports, E-ISSN 2051-817X, Vol. 7, no 17, article id e14143Article in journal (Refereed) Published
Abstract [en]

The present study explores the methods to determine human in vivo protein-specific myofibrillar and collagenous connective tissue protein fractional synthesis and breakdown rates. We found that in human myofibrillar proteins, the protein-bound tracer disappearance method to determine the protein fractional breakdown rate (FBR) (via 2 H2 O ingestion, endogenous labeling of 2 H-alanine that is incorporated into proteins, and FBR quantified by its disappearance from these proteins) has a comparable intrasubject reproducibility (range: 0.09-53.5%) as the established direct-essential amino acid, here L-ring-13 C6 -phenylalanine, incorporation method to determine the muscle protein fractional synthesis rate (FSR) (range: 2.8-56.2%). Further, the determination of the protein breakdown in a protein structure with complex post-translational processing and maturation, exemplified by human tendon tissue, was not achieved in this experimentation, but more investigation is encouraged to reveal the possibility. Finally, we found that muscle protein FBR measured with an essential amino acid tracer prelabeling is inappropriate presumably because of significant and prolonged intracellular recycling, which also may become a significant limitation for determination of the myofibrillar FSR when repeated infusion trials are completed in the same participants.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
Amino acid recycling, deuterated alanine, deuterated water, fractional breakdown rate, fractional synthesis rate, protein turnover, stable isotope
National Category
Physiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5840 (URN)10.14814/phy2.14143 (DOI)000485983500012 ()31496135 (PubMedID)
Available from: 2019-09-17 Created: 2019-09-17 Last updated: 2019-10-11
Blomstrand, E. & Schantz, P. (2019). Berit Sjöberg: 1939-2018. Stockholm
Open this publication in new window or tab >>Berit Sjöberg: 1939-2018
2019 (Swedish)Other (Other (popular science, discussion, etc.))
Place, publisher, year, pages
Stockholm: , 2019. p. 1
Keywords
muskelfysiologi, muskelbiokemi, muskelfibrer, träning, Fysiologiska institutionen, Kungl. Gymnastiska Centralinstitutet, Gymnastik- och idrottshögskolan, Karolinska Institutet, Bengt Saltin, Stig Strand, Ingemar Stenmark
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:gih:diva-5681 (URN)
Available from: 2019-03-27 Created: 2019-03-27 Last updated: 2019-03-29Bibliographically approved
Edman, S., Söderlund, K., Moberg, M., Apro, W. & Blomstrand, E. (2019). mTORC1 Signaling in Individual Human Muscle Fibers Following Resistance Exercise in Combination With Intake of Essential Amino Acids. Frontiers in nutrition, 6, Article ID 96.
Open this publication in new window or tab >>mTORC1 Signaling in Individual Human Muscle Fibers Following Resistance Exercise in Combination With Intake of Essential Amino Acids
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2019 (English)In: Frontiers in nutrition, ISSN 2296-861X, Vol. 6, article id 96Article in journal (Refereed) Published
Abstract [en]

Human muscles contain a mixture of type I and type II fibers with different contractile and metabolic properties. Little is presently known about the effect of anabolic stimuli, in particular nutrition, on the molecular responses of these different fiber types. Here, we examine the effect of resistance exercise in combination with intake of essential amino acids (EAA) on mTORC1 signaling in individual type I and type II human muscle fibers. Five strength-trained men performed two sessions of heavy leg press exercise. During exercise and recovery, the subjects ingested an aqueous solution of EAA (290 mg/kg) or flavored water (placebo). Muscle biopsies were taken from the vastus lateralis before and 90 min after exercise. The biopsies were freeze-dried and single fibers dissected out and weighed (range 0.95-8.1 mu g). The fibers were homogenized individually and identified as type I or II by incubation with antibodies against the different isoforms of myosin. They were also analyzed for both the levels of protein as well as phosphorylation of proteins in the mTORC1 pathway using Western blotting. The levels of the S6K1 and eEF2 proteins were similar to 50% higher in type II than in type I fibers (P < 0.05), but no difference was found between fiber types with respect to the level of mTOR protein. Resistance exercise led to non-significant increases (2-3-fold) in mTOR and S6K1 phosphorylation as well as a 50% decrease (P < 0.05) in eEF2 phosphorylation in both fiber types. Intake of EAA caused a 2 and 6-fold higher (P < 0.05) elevation of mTOR and S6K1 phosphorylation, respectively, in both type I and type II fibers compared to placebo, with no effect on phosphorylation of eEF2. In conclusion, protein levels of S6K1 and eEF2 were significantly higher in type II than type I fibers suggesting higher capacity of the mTOR pathway in type II fibers. Ingestion of EAA enhanced the effect of resistance exercise on phosphorylation of mTOR and S6K1 in both fiber types, but with considerable variation between single fibers of both types.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
muscle fiber type, protein expression, S6K1, single muscle fiber, EAA
National Category
Nutrition and Dietetics
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5807 (URN)10.3389/fnut.2019.00096 (DOI)000472610200002 ()31294029 (PubMedID)
Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14
Edman, S., Söderlund, K. & Blomstrand, E. (2018). Anabolic signalling in individual muscle fibres following resistance exercise in combination with amino acid intake: PO-260. In: Exercise Biochemistry Review: Vol 1 No 5 (2018): Proceedings of IBEC 2018, Beijing, China (PO-201 -> PO-308). Paper presented at 17th International Biochemistry of Exercise Conference (IBEC), October 23-25 2018, Beijing, China.
Open this publication in new window or tab >>Anabolic signalling in individual muscle fibres following resistance exercise in combination with amino acid intake: PO-260
2018 (English)In: Exercise Biochemistry Review: Vol 1 No 5 (2018): Proceedings of IBEC 2018, Beijing, China (PO-201 -> PO-308), 2018Conference paper (Other academic)
Abstract [en]

Objective Human muscle consists of a mixture of fibres with different contractile and metabolic properties, type I (slow-twitch) and type II (fast-twitch) fibres. Little is known about the effect of anabolic stimuli, in particular nutrition, on the molecular response in the different fibre types. Here, we examine the effect of resistance exercise and essential amino acid (EAA) supplementation on mTOR signalling in individual type I and type II human muscle fibres.

Methods Five strength-trained male subjects performed two sessions of leg press exercise (10 x 10 repetition at 62-85 % of 1RM). During exercise and recovery, the subjects ingested an aqueous solution with EAA (290 mg/kg) or flavoured water (placebo). Muscle biopsies were taken from the vastus lateralis before and 90 min after exercise. The biopsies were freeze-dried and single fibres dissected out and weighed (range 0.9 – 8 ug). The fibres were individually homogenized and analysed for proteins in the mTOR pathway using Western blot. Membranes were repeatedly stripped and fibres were identified as type I or type II following incubation with antibodies against the different myosin isoforms.

Results Exercise led to a significant increase in mTOR and p70S6k1 phosphorylation and a fall in eEF2 phosphorylation, similar in both fibre types. There was a large variation between individual fibres; some fibres were highly activated whereas others were not activated at all despite the heavy exercise performed. Intake of EAA caused a 2- to 6-fold higher increase in mTOR and p70S6k1 phosphorylation in both type I and type II fibres as compared to intake of placebo, with no difference between the fibre types. The phosphorylation of eEF2 was not affected by intake of EAA. The total expression of p70S6k1 and eEF2 was 145% and 155% higher in type II than in type I fibres (P<0.05), respectively, whereas no difference between the fibre types was observed for mTOR protein.

Conclusions The response to heavy resistance exercise regarding mTOR signalling was similar in type I and type II fibres in trained subjects, but with a large variation between single fibres of both types. Furthermore, ingestion of EAA enhanced the effect of resistance exercise on phosphorylation of mTOR and p70S6k1 in both fibre types.

National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5476 (URN)10.14428/ebr.v1i5.11083 (DOI)
Conference
17th International Biochemistry of Exercise Conference (IBEC), October 23-25 2018, Beijing, China
Available from: 2018-11-19 Created: 2018-11-19 Last updated: 2018-11-27Bibliographically approved
Blomstrand, E. & Apro, W. (2018). Det viktigaste du behöver veta om protein och träning. Idrottsforskning.se, Article ID 30 maj.
Open this publication in new window or tab >>Det viktigaste du behöver veta om protein och träning
2018 (Swedish)In: Idrottsforskning.se, ISSN 2002-3944, article id 30 majArticle in journal (Other (popular science, discussion, etc.)) Published
Place, publisher, year, edition, pages
Stockholm: Centrum för idrottsforskning, CIF, 2018
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5443 (URN)
Available from: 2018-10-16 Created: 2018-10-16 Last updated: 2018-10-17Bibliographically approved
Blomstrand, E. (2018). Maximera träningen med fokus på kosten. Idrottsmedicin, 37(3), 6-7
Open this publication in new window or tab >>Maximera träningen med fokus på kosten
2018 (Swedish)In: Idrottsmedicin, ISSN 2001-3302, Vol. 37, no 3, p. 6-7Article in journal (Other academic) Published
Abstract [sv]

Med fokus på kosten kan idrottare maximera träningens effekter. Genom att träna med låga glykogendepåer kan den aeroba prestationsförmågan öka och intag av essentiella aminosyror i samband med styrketräning kan stimulera tillväxt av muskelmassa.

Place, publisher, year, edition, pages
Svensk förening för fysisk aktivitet och idrottsmedicin, 2018
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5433 (URN)
Available from: 2018-10-16 Created: 2018-10-16 Last updated: 2018-10-16Bibliographically approved
Bermon, S., Castell, L. M., Calder, P. C., Bishop, N. C., Blomstrand, E., Mooren, F. C., . . . Nagatomi, R. (2017). Consensus Statement Immunonutrition and Exercise.. Exercise immunology review, 23, 8-50
Open this publication in new window or tab >>Consensus Statement Immunonutrition and Exercise.
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2017 (English)In: Exercise immunology review, ISSN 1077-5552, Vol. 23, p. 8-50Article, review/survey (Refereed) Published
Abstract [en]

In this consensus statement on immunonutrition and exercise, a panel of knowledgeable contributors from across the globe provides a consensus of updated science, including the background, the aspects for which a consensus actually exists, the controversies and, when possible, suggested directions for future research.

Keywords
Aging, Biomarkers, Exercise, Immune system, Inflammation, Nutrition, Obesity
National Category
Sport and Fitness Sciences Nutrition and Dietetics
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-4801 (URN)000395708200002 ()28224969 (PubMedID)
Available from: 2017-03-03 Created: 2017-03-03 Last updated: 2018-01-19Bibliographically approved
Apró, W., Moberg, M., Holmberg, H.-C. & Blomstrand, E. (2016). Amino Acid-induced S6K1 Activity In Human Skeletal Muscle Is Mediated By Increased mTor/Rheb Interaction: 128 June 1, 11: 15 AM - 11: 30 AM.. In: Medicine And Science In Sports And Exercise 2016 May; Vol. 48 (5S Suppl 1), pp. 17.: (pp. 17-17). , 48(5S Suppl 1)
Open this publication in new window or tab >>Amino Acid-induced S6K1 Activity In Human Skeletal Muscle Is Mediated By Increased mTor/Rheb Interaction: 128 June 1, 11: 15 AM - 11: 30 AM.
2016 (English)In: Medicine And Science In Sports And Exercise 2016 May; Vol. 48 (5S Suppl 1), pp. 17., 2016, Vol. 48, no 5S Suppl 1, p. 17-17Conference paper, Published paper (Refereed)
Abstract [en]

Cell culture studies have shown that amino acids activate mTORC1 signaling by increasing the interaction between mTOR and its essential activator Rheb. However, the existence of this mechanism in human skeletal muscle remains to be determined.

PURPOSE: To determine if increased mTORC1 signaling in response to amino acids in human skeletal muscle is due to an increased interaction between mTOR and Rheb.

METHODS: Eight well trained men performed resistance exercise on two separate occasions. In connection with the exercise, subjects were supplemented with flavored water (Pla) and essential amino acids (EAA) in a double-blind, randomized cross-over design. Muscle biopsies were taken in the vastus lateralis muscle before, immediately after and 90 and 180 min post exercise. Activity of the mTORC1 pathway was assessed by a radiolabeled in-vitro kinase assay for its immediate downstream target S6K1. Protein-protein interactions were determined by western blot following co-immunoprecipitation of mTOR with Rheb. Co-immunoprecipitation was performed on pooled muscle samples from three of the eight subjects.

RESULTS: Activity of S6K1 remained unchanged immediately after exercise in both trials. However, at 90 min post exercise, S6K1 activity increased by approximately 2- and 8-fold (p<0.05) from baseline the Pla and EAA trials, respectively. At the 180 min time point, S6K1 activity remained elevated in both trials being approx. 3-fold higher in the Pla trial and 5-fold higher (p<0.05) in the EAA trial. The fold-change in mTOR and Rheb interaction largely resembled the activity pattern of S6K1 in both trials; in the Pla trial the fold-change was 0.9, 1.3 and 1.4 while in the EAA trial the fold-change was 1.6, 2.9 and 1.9 immediately after, 90 min after and 180 min after exercise, respectively.

CONCLUSIONS: The large increase in S6K1 activity following EAA intake appears to be mediated by an increased interaction between mTOR and its proximal activator Rheb. This is the first time this mechanism has been demonstrated in human skeletal muscle.

National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-4514 (URN)
Available from: 2016-08-05 Created: 2016-08-05 Last updated: 2016-08-08Bibliographically approved
Kazior, Z., Willis, S. J., Moberg, M., Apró, W., Calbet, J. A., Holmberg, H.-C. & Blomstrand, E. (2016). Endurance Exercise Enhances the Effect of Strength Training on Muscle Fiber Size and Protein Expression of Akt and mTOR.. PLoS ONE, 11(2), Article ID e0149082.
Open this publication in new window or tab >>Endurance Exercise Enhances the Effect of Strength Training on Muscle Fiber Size and Protein Expression of Akt and mTOR.
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2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 2, article id e0149082Article in journal (Refereed) Published
Abstract [en]

Reports concerning the effect of endurance exercise on the anabolic response to strength training have been contradictory. This study re-investigated this issue, focusing on training effects on indicators of protein synthesis and degradation. Two groups of male subjects performed 7 weeks of resistance exercise alone (R; n = 7) or in combination with preceding endurance exercise, including both continuous and interval cycling (ER; n = 9). Muscle biopsies were taken before and after the training period. Similar increases in leg-press 1 repetition maximum (30%; P<0.05) were observed in both groups, whereas maximal oxygen uptake was elevated (8%; P<0.05) only in the ER group. The ER training enlarged the areas of both type I and type II fibers, whereas the R protocol increased only the type II fibers. The mean fiber area increased by 28% (P<0.05) in the ER group, whereas no significant increase was observed in the R group. Moreover, expression of Akt and mTOR protein was enhanced in the ER group, whereas only the level of mTOR was elevated following R training. Training-induced alterations in the levels of both Akt and mTOR protein were correlated to changes in type I fiber area (r = 0.55-0.61, P<0.05), as well as mean fiber area (r = 0.55-0.61, P<0.05), reflecting the important role played by these proteins in connection with muscle hypertrophy. Both training regimes reduced the level of MAFbx protein (P<0.05) and tended to elevate that of MuRF-1. The present findings indicate that the larger hypertrophy observed in the ER group is due more to pronounced stimulation of anabolic rather than inhibition of catabolic processes.

National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-4363 (URN)10.1371/journal.pone.0149082 (DOI)000371218400061 ()26885978 (PubMedID)
Available from: 2016-02-24 Created: 2016-02-24 Last updated: 2017-11-30Bibliographically approved
Apro, W., Moberg, M., Ekblom, B., Holmberg, H.-C. & Blomstrand, E. (2016). High intensity interval cycling performed prior to resistance exercise stimulates autophagy signaling. In: Conference program & abstracts: . Paper presented at 2016 APS Intersociety Meeting. The Integrative Biology of Exercise VII. November 2-4 2016, Phoenix, Arizona. (pp. 84-84).
Open this publication in new window or tab >>High intensity interval cycling performed prior to resistance exercise stimulates autophagy signaling
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2016 (English)In: Conference program & abstracts, 2016, p. 84-84Conference paper, Oral presentation with published abstract (Other academic)
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-4631 (URN)
Conference
2016 APS Intersociety Meeting. The Integrative Biology of Exercise VII. November 2-4 2016, Phoenix, Arizona.
Available from: 2016-11-08 Created: 2016-11-08 Last updated: 2017-03-31
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6537-042X

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