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Deane C, Piasecki M, Atherton P. Skeletal muscle immobilisation-induced atrophy: mechanistic insights from human studies. Clin Sci (Lond) 2024; 138:741-756. [PMID: 38895777 PMCID: PMC11186857 DOI: 10.1042/cs20231198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 05/28/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024]
Abstract
Periods of skeletal muscle disuse lead to rapid declines in muscle mass (atrophy), which is fundamentally underpinned by an imbalance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB). The complex interplay of molecular mechanisms contributing to the altered regulation of muscle protein balance during disuse have been investigated but rarely synthesised in the context of humans. This narrative review discusses human models of muscle disuse and the ensuing inversely exponential rate of muscle atrophy. The molecular processes contributing to altered protein balance are explored, with a particular focus on growth and breakdown signalling pathways, mitochondrial adaptations and neuromuscular dysfunction. Finally, key research gaps within the disuse atrophy literature are highlighted providing future avenues to enhance our mechanistic understanding of human disuse atrophy.
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Affiliation(s)
- Colleen S. Deane
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, U.K
| | - Matthew Piasecki
- Centre of Metabolism, Ageing and Physiology (CoMAP), Medical Research Council/Versus Arthritis UK Centre of Excellence for Musculoskeletal Ageing Research (CMAR), National Institute of Health Research (NIHR) Biomedical Research Centre (BRC), University of Nottingham, U.K
| | - Philip J. Atherton
- Centre of Metabolism, Ageing and Physiology (CoMAP), Medical Research Council/Versus Arthritis UK Centre of Excellence for Musculoskeletal Ageing Research (CMAR), National Institute of Health Research (NIHR) Biomedical Research Centre (BRC), University of Nottingham, U.K
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2
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Durak A, Binay Safer V, Catikkas NM. The relationship between pressure injuries and ultrasonographically measured rectus femoris muscle thickness. J Tissue Viability 2024; 33:60-66. [PMID: 38103986 DOI: 10.1016/j.jtv.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 11/13/2023] [Accepted: 12/07/2023] [Indexed: 12/19/2023]
Affiliation(s)
- Ayfer Durak
- University of Health Sciences Istanbul, Hamidiye Faculty of Medicine, Sancaktepe Prof. Dr. Ilhan Varank Training and Research Hospital, Department of Internal Medicine, Division of Geriatrics, Sancaktepe, 34785, Istanbul, Turkey.
| | - Vildan Binay Safer
- University of Health Sciences Istanbul, Hamidiye Faculty of Medicine, Sancaktepe Prof. Dr. Ilhan Varank Training and Research Hospital, Department of Internal Medicine / Department of Physical Medicine and Rehabilitation, Sancaktepe, 34785, Istanbul, Turkey
| | - Nezahat Muge Catikkas
- University of Health Sciences Istanbul, Hamidiye Faculty of Medicine, Sancaktepe Prof. Dr. Ilhan Varank Training and Research Hospital, Department of Internal Medicine, Division of Geriatrics, Sancaktepe, 34785, Istanbul, Turkey
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Sayed RKA, Hibbert JE, Jorgenson KW, Hornberger TA. The Structural Adaptations That Mediate Disuse-Induced Atrophy of Skeletal Muscle. Cells 2023; 12:2811. [PMID: 38132132 PMCID: PMC10741885 DOI: 10.3390/cells12242811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/23/2023] Open
Abstract
The maintenance of skeletal muscle mass plays a fundamental role in health and issues associated with quality of life. Mechanical signals are one of the most potent regulators of muscle mass, with a decrease in mechanical loading leading to a decrease in muscle mass. This concept has been supported by a plethora of human- and animal-based studies over the past 100 years and has resulted in the commonly used term of 'disuse atrophy'. These same studies have also provided a great deal of insight into the structural adaptations that mediate disuse-induced atrophy. For instance, disuse results in radial atrophy of fascicles, and this is driven, at least in part, by radial atrophy of the muscle fibers. However, the ultrastructural adaptations that mediate these changes remain far from defined. Indeed, even the most basic questions, such as whether the radial atrophy of muscle fibers is driven by the radial atrophy of myofibrils and/or myofibril hypoplasia, have yet to be answered. In this review, we thoroughly summarize what is known about the macroscopic, microscopic, and ultrastructural adaptations that mediated disuse-induced atrophy and highlight some of the major gaps in knowledge that need to be filled.
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Affiliation(s)
- Ramy K. A. Sayed
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Sohag University, Sohag 82524, Egypt
| | - Jamie E. Hibbert
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Kent W. Jorgenson
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Troy A. Hornberger
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
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4
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Yang K, Hou R, Zhao J, Wang X, Wei J, Pan X, Zhu X. Lifestyle effects on aging and CVD: A spotlight on the nutrient-sensing network. Ageing Res Rev 2023; 92:102121. [PMID: 37944707 DOI: 10.1016/j.arr.2023.102121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/12/2023] [Accepted: 11/04/2023] [Indexed: 11/12/2023]
Abstract
Aging is widespread worldwide and a significant risk factor for cardiovascular disease (CVD). Mechanisms underlying aging have attracted considerable attention in recent years. Remarkably, aging and CVD overlap in numerous ways, with deregulated nutrient sensing as a common mechanism and lifestyle as a communal modifier. Interestingly, lifestyle triggers or suppresses multiple nutrient-related signaling pathways. In this review, we first present the composition of the nutrient-sensing network (NSN) and its metabolic impact on aging and CVD. Secondly, we review how risk factors closely associated with CVD, including adverse life states such as sedentary behavior, sleep disorders, high-fat diet, and psychosocial stress, contribute to aging and CVD, with a focus on the bridging role of the NSN. Finally, we focus on the positive effects of beneficial dietary interventions, specifically dietary restriction and the Mediterranean diet, on the regulation of nutrient metabolism and the delayed effects of aging and CVD that depend on the balance of the NSN. In summary, we expound on the interaction between lifestyle, NSN, aging, and CVD.
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Affiliation(s)
- Kaiying Yang
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Rongyao Hou
- Department of Neurology, The Affiliated Hiser Hospital of Qingdao University, Qingdao 266000, China
| | - Jie Zhao
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Xia Wang
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Jin Wei
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Xudong Pan
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao 266000, China.
| | - Xiaoyan Zhu
- Department of Critical Care Medicine, The Affiliated Hospital of Qingdao University, Qingdao 266000, China.
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Herda AA, Nabavizadeh O. Effect of six weeks of resistance training on bone preservation in older adults: a randomized control trial. Aging Clin Exp Res 2023; 35:2633-2641. [PMID: 37838645 DOI: 10.1007/s40520-023-02575-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/20/2023] [Indexed: 10/16/2023]
Abstract
BACKGROUND It has been established that chronic resistance exercise contributes to positive changes to bone in older adults. AIMS This study evaluated the effect of 6 weeks of resistance exercise with either elastic bands or dumbbells vs. a control period on bone morphology of older adults. METHODS Fifty-seven adults (mean ± SD; age = 66.5 ± 7.09 yrs; height = 165.2 ± 10.6 cm; body mass = 74.5 ± 14.6 kg) were randomized into three groups (dumbbell, elastic, or control). Participants underwent a total body dual-energy X-ray absorptiometry (DXA) scan for total body and segmental bone mineral content (BMC) and bone mineral density (BMD) before and following 6-week intervention. Age-matched Z-scores for BMD and BMC were recorded. Data were analyzed using two-way repeated measures ANOVAs and 0.05 significance level. RESULTS BMCarm improved for the dumbbell group (p = 0.016) after the training, with no change in BMD for any group (p > 0.05). Additionally, significant (time x treatment group) interaction (p = 0.024) of age-matched Z-scores indicated an improvement in only the dumbbell group after 6 weeks (p = 0.015), with no change in the elastic group despite them having greater Z-scores than the control group. DISCUSSION This study is the first to demonstrate acute normative adaptations as dumbbell-based programs may promote positive maintenance of bone metrics over 6 weeks, despite the lack of significant change in absolute BMC or BMD. CONCLUSION Adults did not lose relative bone mass with acute exercise using dumbbells as the external load applied and this may lead to positive changes following chronic training. There was no bone-related impact from elastic bands, suggesting a weighted load or force produced relative to gravity is beneficial.
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Affiliation(s)
- Ashley A Herda
- Department of Health, Sport, and Exercise Sciences, University of Kansas Edwards Campus, 12604 Quivira Road, BEST 350X, Overland Park, KS, 66213, USA.
| | - Omid Nabavizadeh
- Department of Geriatric Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO, USA
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Raffin J, de Souto Barreto P, Le Traon AP, Vellas B, Aubertin-Leheudre M, Rolland Y. Sedentary behavior and the biological hallmarks of aging. Ageing Res Rev 2023; 83:101807. [PMID: 36423885 DOI: 10.1016/j.arr.2022.101807] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 11/09/2022] [Accepted: 11/20/2022] [Indexed: 11/23/2022]
Abstract
While the benefits of physical exercise for a healthy aging are well-recognized, a growing body of evidence shows that sedentary behavior has deleterious health effects independently, to some extent, of physical activity levels. Yet, the increasing prevalence of sedentariness constitutes a major public health issue that contributes to premature aging but the potential cellular mechanisms through which prolonged immobilization may accelerate biological aging remain unestablished. This narrative review summarizes the impact of sedentary behavior using different models of extreme sedentary behaviors including bedrest, unilateral limb suspension and space travel studies, on the hallmarks of aging such as genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. We further highlight the remaining knowledge gaps that need more research in order to promote healthspan extension and to provide future contributions to the field of geroscience.
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Affiliation(s)
- Jérémy Raffin
- Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse, 37 Allées Jules Guesdes, 31000 Toulouse, France.
| | - Philipe de Souto Barreto
- Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse, 37 Allées Jules Guesdes, 31000 Toulouse, France; CERPOP UMR 1295, University of Toulouse III, Inserm, UPS, Toulouse, France
| | - Anne Pavy Le Traon
- Institute for Space Medicine and Physiology (MEDES), Neurology Department CHU Toulouse, INSERM U 1297, Toulouse, France
| | - Bruno Vellas
- Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse, 37 Allées Jules Guesdes, 31000 Toulouse, France; CERPOP UMR 1295, University of Toulouse III, Inserm, UPS, Toulouse, France
| | - Mylène Aubertin-Leheudre
- Département des Sciences de l'activité physique, Faculté des sciences, Université du Québec à Montréal, Montreal, Canada; Centre de recherche, Institut universitaire de gériatrie de Montréal (IUGM), CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montreal, Canada, Faculté des sciences, Université du Québec à Montréal, Montreal, Canada
| | - Yves Rolland
- Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse, 37 Allées Jules Guesdes, 31000 Toulouse, France; CERPOP UMR 1295, University of Toulouse III, Inserm, UPS, Toulouse, France
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7
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Black MN, Wilkinson JA, Webb EK, Kamal M, Bahniwal R, McGlory C, Phillips SM, Devries MC. Two weeks of single-leg immobilization alters intramyocellular lipid storage characteristics in healthy, young women. J Appl Physiol (1985) 2021; 130:1247-1258. [PMID: 33630674 DOI: 10.1152/japplphysiol.00878.2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Muscle disuse rapidly induces insulin resistance (IR). Despite a relationship between intramyocellular lipid (IMCL) content and IR, during muscle-disuse IR develops before IMCL accumulation, suggesting that IMCL are not related to disuse-induced IR. However, recent studies show that it is not total IMCL content, but IMCL size and location that are related to IR. Changes in these IMCL parameters may occur prior to increases in IMCL content, thus contributing to disuse-induced IR. Omega-3 fatty acids may mitigate the effects of disuse on IR by preventing a decline in insulin signaling proteins. Twenty women (age 22 ± 3 yr) received either 5 g·day-1 omega-3 fatty acid or isoenergetic sunflower oil for 4 wk prior to, throughout 2 wk of single-leg immobilization, and during 2 wk of recovery. Changes in IMCL characteristics and insulin signaling proteins were examined in vastus lateralis samples taken before supplementation and immobilization, and following immobilization and recovery. Omega-3 supplementation had no effect. IMCL area density decreased in the subsarcolemmal region during immobilization and recovery (-19% and -56%, respectively, P = 0.009). IMCL size increased in the central intermyofibrillar region during immobilization (43%, P = 0.007), returning to baseline during recovery. PLIN5 and AKT increased during immobilization (87%, P = 0.002; 30%, P = 0.007, respectively). PLIN 5 remained elevated and AKT increased further (15%) during recovery. IRS1, AS160, and GLUT4 decreased during immobilization (-35%, P = 0.001; -44%, P = 0.03; -56%, P = 0.02, respectively), returning to baseline during recovery. Immobilization alters IMCL storage characteristics while negatively affecting unstimulated insulin signaling protein content in young women.NEW & NOTEWORTHY We report that the subcellular storage location of IMCL is altered by limb immobilization, highlighting the need to evaluate IMCL storage location when assessing the effects of disuse on IMCL content. We also found that AKT content increased during immobilization in our female population, contrary to studies in males finding that AKT decreases during disuse, highlighting that men and women may respond differently to disuse and the necessity to include women in all research.
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Affiliation(s)
- Merryl N Black
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | | | - Erin K Webb
- Department of Kinesiology, University of McMaster, Hamilton, Ontario, Canada
| | - Michael Kamal
- Department of Kinesiology, University of McMaster, Hamilton, Ontario, Canada
| | - Ravninder Bahniwal
- Department of Kinesiology, University of McMaster, Hamilton, Ontario, Canada
| | - Chris McGlory
- Department of Kinesiology, University of McMaster, Hamilton, Ontario, Canada
| | - Stuart M Phillips
- Department of Kinesiology, University of McMaster, Hamilton, Ontario, Canada
| | - Michaela C Devries
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Møller AB, Vendelbo MH, Schjerling P, Couppé C, Møller N, Kjær M, Hansen M, Jessen N. Immobilization Decreases FOXO3a Phosphorylation and Increases Autophagy-Related Gene and Protein Expression in Human Skeletal Muscle. Front Physiol 2019; 10:736. [PMID: 31258486 PMCID: PMC6587099 DOI: 10.3389/fphys.2019.00736] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/27/2019] [Indexed: 01/07/2023] Open
Abstract
Immobilization of the lower limbs promotes a catabolic state that reduces muscle mass, whereas physical training promotes an anabolic state that increases muscle mass. Understanding the molecular mechanisms underlying this is of clinical interest, as loss of muscle mass is a major complication to critical illness in humans. To determine the molecular regulation of protein synthesis and degradation during muscle loss and hypertrophy, we examined skeletal muscle biopsies from healthy human subjects after 2 weeks unilateral immobilization of a lower limb and during 6 weeks of physical rehabilitation. We have previously shown that cross-sectional area of the knee muscle-extensors decreased by ∼10% during immobilization and was completely restored during rehabilitation. Here we provide novel data to suggest that autophagy is an important underlying mechanism involved in regulation of muscle mass. Protein expression of MuRF1 and ATROGIN-1 did not change during the study, indicating that the recruitment of substrates to the proteasomes was unaltered. Phosphorylation of mTORat Ser2448 did not change during the study, and neither did phosphorylation of the mTORC1 substrates 4EBP1 Thr37/46 and p70S6K Thr389, suggesting that this pathway does not suppress protein synthesis during muscle wasting. Protein levels of p62 and ULK1 increased during immobilization and returned to baseline levels during rehabilitation. Same pattern was observed for FOXO3a phosphorylation at Ser318/321, suggesting transcriptional activation during immobilization and inactivation during rehabilitation. To investigate this further, we analyzed mRNA expression of seven autophagy-related genes controlled by FOXO3a. Five of these (p62, LC3B, BECLIN-1, ATG12, and BNIP3) increased during immobilization and returned to baseline during rehabilitation. In conclusion, immobilization of a lower limb increases autophagy-related gene and protein expression in human skeletal muscle in a pattern that mirrors FOXO3a phosphorylation. These findings could imply that FOXO3a dependent transcriptional regulation of autophagy is involved in the regulation of muscle mass in humans.
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Affiliation(s)
- Andreas Buch Møller
- Research Laboratory for Biochemical Pathology, Institute for Clinical Medicine, Aarhus University, Aarhus, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Mikkel Holm Vendelbo
- Department of Nuclear Medicine & PET-Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Peter Schjerling
- Department of Orthopaedic Surgery M, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, Institute of Sports Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Christian Couppé
- Department of Orthopaedic Surgery M, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, Institute of Sports Medicine, University of Copenhagen, Copenhagen, Denmark.,Musculoskeletal Rehabilitation Research Unit, Department of Physical Therapy, Bispebjerg Hospital, Copenhagen, Denmark
| | - Niels Møller
- Medical Research Laboratory, Institute for Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Michael Kjær
- Department of Orthopaedic Surgery M, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, Institute of Sports Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Mette Hansen
- Department of Orthopaedic Surgery M, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, Institute of Sports Medicine, University of Copenhagen, Copenhagen, Denmark.,Section of Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Niels Jessen
- Research Laboratory for Biochemical Pathology, Institute for Clinical Medicine, Aarhus University, Aarhus, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
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Rooks DS, Laurent D, Praestgaard J, Rasmussen S, Bartlett M, Tankó LB. Effect of bimagrumab on thigh muscle volume and composition in men with casting-induced atrophy. J Cachexia Sarcopenia Muscle 2017; 8:727-734. [PMID: 28905498 PMCID: PMC5659065 DOI: 10.1002/jcsm.12205] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/30/2017] [Accepted: 03/01/2017] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Patients experiencing disuse atrophy report acute loss of skeletal muscle mass which subsequently leads to loss of strength and physical capacity. In such patients, especially the elderly, complete recovery remains a challenge even with improved nutrition and resistance exercise. This study aimed to explore the clinical potential of bimagrumab, a human monoclonal antibody targeting the activin type II receptor, for the recovery of skeletal muscle volume from disuse atrophy using an experimental model of lower extremity immobilization. METHODS In this double-blind, placebo-controlled trial, healthy young men (n = 24; mean age, 24.1 years) were placed in a full-length cast of one of the lower extremities for 2 weeks to induce disuse atrophy. After cast removal, subjects were randomized to receive a single intravenous (i.v.) dose of either bimagrumab 30 mg/kg (n = 15) or placebo (n = 9) and were followed for 12 weeks. Changes in thigh muscle volume (TMV) and inter-muscular adipose tissue (IMAT) and subcutaneous adipose tissue (SCAT) of the thigh, maximum voluntary knee extension strength, and safety were assessed throughout the 12 week study. RESULTS Casting resulted in an average TMV loss of -4.8% and comparable increases in IMAT and SCAT volumes. Bimagrumab 30 mg/kg i.v. resulted in a rapid increase in TMV at 2 weeks following cast removal and a +5.1% increase above pre-cast levels at 12 weeks. In comparison, TMV returned to pre-cast level at 12 weeks (-0.1%) in the placebo group. The increased adiposity of the casted leg was sustained in the placebo group and decreased substantially in the bimagrumab group at Week 12 (IMAT: -6.6%, SCAT: -3.5%). Knee extension strength decreased by ~25% in the casted leg for all subjects and returned to pre-cast levels within 6 weeks after cast removal in both treatment arms. Bimagrumab was well tolerated with no serious or severe adverse events reported during the study. CONCLUSIONS A single dose of bimagrumab 30 mg/kg i.v. safely accelerated the recovery of TMV and reversal of accumulated IMAT following 2 weeks in a joint-immobilizing cast.
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Affiliation(s)
- Daniel S Rooks
- Translational Medicine, Novartis Institutes for BioMedical Research, Cambridge, MA, 02139, USA
| | - Didier Laurent
- Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Jens Praestgaard
- Translational Medicine, Novartis Institutes for BioMedical Research, Cambridge, MA, 02139, USA
| | | | - Michael Bartlett
- Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland
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10
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Slimani L, Vazeille E, Deval C, Meunier B, Polge C, Dardevet D, Béchet D, Taillandier D, Micol D, Listrat A, Attaix D, Combaret L. The delayed recovery of the remobilized rat tibialis anterior muscle reflects a defect in proliferative and terminal differentiation that impairs early regenerative processes. J Cachexia Sarcopenia Muscle 2015; 6:73-83. [PMID: 26136414 PMCID: PMC4435099 DOI: 10.1002/jcsm.12011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 10/09/2014] [Accepted: 10/15/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The immobilization-induced tibialis anterior (TA) muscle atrophy worsens after cast removal and is associated with altered extracellular matrix (ECM) composition. The secreted protein acidic and rich in cysteine (Sparc) is an ECM component involved in Akt activation and in β-catenin stabilization, which controls protein turnover and induces muscle regulatory factors (MRFs), respectively. We hypothesized that ECM alterations may influence these intracellular signalling pathways controlling TA muscle mass. METHODS Six-month-old Wistar rats were subjected to hindlimb cast immobilization for 8 days (I8) or not (I0) and allowed to recover for 1 to 10 days (R1-10). RESULTS The TA atrophy during remobilization correlated with reduced fibre cross-sectional area and thickening of endomysium. mRNA levels for Sparc increased during remobilization until R10 and for integrin-α7 and -β1 at I8 and R1. Integrin-linked kinase protein levels increased during immobilization and remobilization until R10. This was inversely correlated with changes in Akt phosphorylation. β-Catenin protein levels increased in the remobilized TA at R1 and R10. mRNA levels of the proliferative MRFs (Myf5 and MyoD) increased at I8 and R1, respectively, without changes in Myf5 protein levels. In contrast, myogenin mRNA levels (a terminal differentiation MRF) decreased at R1, but only increased at R10 in remobilized muscles, as for protein levels. CONCLUSIONS Altogether, this suggests that the TA inefficiently attempted to preserve regeneration during immobilization by increasing transcription of proliferative MRFs, and that the TA could engage recovery during remobilization only when the terminal differentiation step of regeneration is enhanced.
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Affiliation(s)
- Lamia Slimani
- INRA, UMR 1019, UNH, CRNH, F-63000, Auvergne, Clermont-Ferrand, France.,Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000, Clermont-Ferrand, France
| | - Emilie Vazeille
- Centre Hospitalier Universitaire, 63000, Clermont-Ferrand, France
| | - Christiane Deval
- INRA, UMR 1019, UNH, CRNH, F-63000, Auvergne, Clermont-Ferrand, France.,Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000, Clermont-Ferrand, France
| | - Bruno Meunier
- INRA, UMR 1213 Herbivores, 63122, Saint Genès Champanelle, France
| | - Cécile Polge
- INRA, UMR 1019, UNH, CRNH, F-63000, Auvergne, Clermont-Ferrand, France.,Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000, Clermont-Ferrand, France
| | - Dominique Dardevet
- INRA, UMR 1019, UNH, CRNH, F-63000, Auvergne, Clermont-Ferrand, France.,Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000, Clermont-Ferrand, France
| | - Daniel Béchet
- INRA, UMR 1019, UNH, CRNH, F-63000, Auvergne, Clermont-Ferrand, France.,Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000, Clermont-Ferrand, France
| | - Daniel Taillandier
- INRA, UMR 1019, UNH, CRNH, F-63000, Auvergne, Clermont-Ferrand, France.,Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000, Clermont-Ferrand, France
| | - Didier Micol
- INRA, UMR 1213 Herbivores, 63122, Saint Genès Champanelle, France
| | - Anne Listrat
- INRA, UMR 1213 Herbivores, 63122, Saint Genès Champanelle, France
| | - Didier Attaix
- INRA, UMR 1019, UNH, CRNH, F-63000, Auvergne, Clermont-Ferrand, France.,Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000, Clermont-Ferrand, France
| | - Lydie Combaret
- INRA, UMR 1019, UNH, CRNH, F-63000, Auvergne, Clermont-Ferrand, France.,Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000, Clermont-Ferrand, France
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Vigelsø A, Dybboe R, Hansen CN, Dela F, Helge JW, Guadalupe Grau A. GAPDH and β-actin protein decreases with aging, making Stain-Free technology a superior loading control in Western blotting of human skeletal muscle. J Appl Physiol (1985) 2014; 118:386-94. [PMID: 25429098 DOI: 10.1152/japplphysiol.00840.2014] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Reference proteins (RP) or the total protein (TP) loaded is used to correct for uneven loading and/or transfer in Western blotting. However, the signal sensitivity and the influence of physiological conditions may question the normalization methods. Therefore, three widely used reference proteins [β-actin, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and α-tubulin], as well as TP loaded measured by Stain-Free technology (SF) as normalization tool were tested. This was done using skeletal muscle samples from men subjected to physiological conditions often investigated in applied physiology where the intervention has been suggested to impede normalization (ageing, muscle atrophy, and different muscle fiber type composition). The linearity of signal and the methodological variation coefficient was obtained. Furthermore, the inter- and intraindividual variation in signals obtained from SF and RP was measured in relation to ageing, muscle atrophy, and different muscle fiber type composition, respectively. A stronger linearity of SF and β-actin compared with GAPDH and α-tubulin was observed. The methodological variation was relatively low in all four methods (4-11%). Protein level of β-actin and GAPDH was lower in older men compared with young men. In conclusion, β-actin, GAPDH, and α-tubulin may not be used for normalization in studies that include subjects with a large age difference. In contrast, the RPs may not be affected in studies that include muscle wasting and differences in muscle fiber type. The novel SF technology adds lower variation to the results compared with the existing methods for correcting for loading inaccuracy in Western blotting of human skeletal muscle in applied physiology.
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Affiliation(s)
- Andreas Vigelsø
- Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark
| | - Rie Dybboe
- Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark
| | - Christina Neigaard Hansen
- Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark
| | - Flemming Dela
- Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark
| | - Jørn W Helge
- Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark
| | - Amelia Guadalupe Grau
- Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark
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