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Dumitru A, Radu BM, Radu M, Cretoiu SM. Muscle Changes During Atrophy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1088:73-92. [PMID: 30390248 DOI: 10.1007/978-981-13-1435-3_4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Muscle atrophy typically is a direct effect of protein degradation induced by a diversity of pathophysiologic states such as disuse, immobilization, denervation, aging, sepsis, cachexia, glucocorticoid treatment, hereditary muscular disorders, cancer, diabetes and obesity, kidney and heart failure, and others. Muscle atrophy is defined by changes in the muscles, consisting in shrinkage of myofibers, changes in the types of fiber and myosin isoforms, and a net loss of cytoplasm, organelles and overall a protein loss. Although in the literature there are extensive studies in a range of animal models, the paucity of human data is a reality. This chapter is focused on various aspects of muscle wasting and describes the transitions of myofiber types during the progression of muscle atrophy in several pathological states. Clinical conditions associated with muscle atrophy have been grouped based on the fast-to-slow or slow-to-fast fiber-type shifts. We have also summarized the ultrastructural and histochemical features characteristic for muscle atrophy in clinical and experimental models for aging, cancer, diabetes and obesity, and heart failure and arrhythmia.
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Affiliation(s)
- Adrian Dumitru
- Department of Pathology, Emergency University Hospital, Bucharest, Romania
| | - Beatrice Mihaela Radu
- Faculty of Biology, Department of Anatomy, Animal Physiology and Biophysics, University of Bucharest, Bucharest, Romania.,Life, Environmental and Earth Sciences Division, Research Institute of the University of Bucharest (ICUB), Bucharest, Romania
| | - Mihai Radu
- Department of Life & Environmental Physics, 'Horia Hulubei' National Institute for Physics & Nuclear Engineering, Magurele, Romania
| | - Sanda Maria Cretoiu
- Division of Cell and Molecular Biology and Histology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
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Itoh Y, Murakami T, Mori T, Agata N, Kimura N, Inoue-Miyazu M, Hayakawa K, Hirano T, Sokabe M, Kawakami K. Training at non-damaging intensities facilitates recovery from muscle atrophy. Muscle Nerve 2016; 55:243-253. [PMID: 27301985 DOI: 10.1002/mus.25218] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2016] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Resistance training promotes recovery from muscle atrophy, but optimum training programs have not been established. We aimed to determine the optimum training intensity for muscle atrophy. METHODS Mice recovering from atrophied muscles after 2 weeks of tail suspension underwent repeated isometric training with varying joint torques 50 times per day. RESULTS Muscle recovery assessed by maximal isometric contraction and myofiber cross-sectional areas (CSAs) were facilitated at 40% and 60% maximum contraction strength (MC), but at not at 10% and 90% MC. At 60% and 90% MC, damaged and contained smaller diameter fibers were observed. Activation of myogenic satellite cells and a marked increase in myonuclei were observed at 40%, 60%, and 90% MC. CONCLUSIONS The increases in myofiber CSAs were likely caused by increased myonuclei formed through fusion of resistance-induced myofibers with myogenic satellite cells. These data indicate that resistance training without muscle damage facilitates efficient recovery from atrophy. Muscle Nerve 55: 243-253, 2017.
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Affiliation(s)
- Yuta Itoh
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Faculty of Rehabilitation Science, Nagoya Gakuin University, Seto, Japan
| | - Taro Murakami
- Faculty of Wellness, Shigakkan University, Ohbu, Japan
| | - Tomohiro Mori
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobuhide Agata
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Faculty of Health and Medical Sciences, Tokoha University, Hamamatsu, Japan
| | - Nahoko Kimura
- Aiche Medical College for Physical and Occupational Therapy, Kiyosu, Japan
| | | | - Kimihide Hayakawa
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takayuki Hirano
- Faculty of Rehabilitation Science, Nagoya Gakuin University, Seto, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Keisuke Kawakami
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Faculty of Welfare and Health Sciences, Oita University, Dannoharu 700, Oita City, 870-1192, Japan
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Many GM, Yokosaki Y, Uaesoontrachoon K, Nghiem PP, Bello L, Dadgar S, Yin Y, Damsker JM, Cohen HB, Kornegay JN, Bamman MM, Mosser DM, Nagaraju K, Hoffman EP. OPN-a induces muscle inflammation by increasing recruitment and activation of pro-inflammatory macrophages. Exp Physiol 2016; 101:1285-1300. [PMID: 27452303 PMCID: PMC5095808 DOI: 10.1113/ep085768] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/15/2016] [Indexed: 02/06/2023]
Abstract
New Findings What is the central question of this study? What is the functional relevance of OPN isoform expression in muscle pathology? What is the main finding and its importance? The full‐length human OPN‐a isoform is the most pro‐inflammatory isoform in the muscle microenvironment, acting on macrophages and myoblasts in an RGD‐integrin‐dependent manner. OPN‐a upregulates expression of tenascin‐C (TNC), a known Toll‐like receptor 4 (TLR4) agonist. Blocking TLR4 signalling inhibits the pro‐inflammatory effects of OPN‐a, suggesting that a potential mechanism of OPN action is by promoting TNC–TLR4 signalling.
Although osteopontin (OPN) is an important mediator of muscle remodelling in health and disease, functional differences in human spliced OPN variants in the muscle microenvironment have not been characterized. We thus sought to define the pro‐inflammatory activities of human OPN isoforms (OPN‐a, OPN‐b and OPN‐c) on cells present in regenerating muscle. OPN transcripts were quantified in normal and dystrophic human and dog muscle. Human macrophages and myoblasts were stimulated with recombinant human OPN protein isoforms, and cytokine mRNA and protein induction was assayed. OPN isoforms were greatly increased in dystrophic human (OPN‐a > OPN‐b > OPN‐c) and dog muscle (OPN‐a = OPN‐c). In healthy human muscle, mechanical loading also upregulated OPN‐a expression (eightfold; P < 0.01), but did not significantly upregulate OPN‐c expression (twofold; P > 0.05). In vitro, OPN‐a displayed the most pronounced pro‐inflammatory activity among isoforms, acting on both macrophages and myoblasts. In vitro and in vivo data revealed that OPN‐a upregulated tenascin‐C (TNC), a known Toll‐like receptor 4 (TLR4) agonist. Inhibition of TLR4 signalling attenuated OPN‐mediated macrophage cytokine production. In summary, OPN‐a is the most abundant and functionally active human spliced isoform in the skeletal muscle microenvironment. Here, OPN‐a promotes pro‐inflammatory signalling in both macrophages and myoblasts, possibly through induction of TNC–TLR4 signalling. Together, our findings suggest that specific targeting of OPN‐a and/or TNC signalling in the damaged muscle microenvironment may be of therapeutic relevance.
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Affiliation(s)
- Gina M Many
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA.,Department of Integrative Systems Biology, George Washington University School of Medicine & Health Sciences, Washington, DC, USA.,Department of Cell, Developmental and Integrative Biology, University of Alabama Birmingham, Birmingham, AL, USA
| | | | | | - Peter P Nghiem
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA.,Department of Integrative Systems Biology, George Washington University School of Medicine & Health Sciences, Washington, DC, USA.,Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
| | - Luca Bello
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA
| | - Sherry Dadgar
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA
| | - Ying Yin
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Jesse M Damsker
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA.,ReveraGen BioPharma, Rockville, MD, USA
| | - Heather B Cohen
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
| | - Marcas M Bamman
- Department of Cell, Developmental and Integrative Biology, University of Alabama Birmingham, Birmingham, AL, USA
| | - David M Mosser
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
| | - Kanneboyina Nagaraju
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA.,Department of Integrative Systems Biology, George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Eric P Hoffman
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC, USA. .,Department of Integrative Systems Biology, George Washington University School of Medicine & Health Sciences, Washington, DC, USA.
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Itoh Y, Hayakawa K, Mori T, Agata N, Inoue-Miyazu M, Murakami T, Sokabe M, Kawakami K. Stand-up exercise training facilitates muscle recovery from disuse atrophy by stimulating myogenic satellite cell proliferation in mice. Physiol Rep 2014; 2:2/11/e12185. [PMID: 25367692 PMCID: PMC4255801 DOI: 10.14814/phy2.12185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Determining the cellular and molecular recovery processes in inactivity – or unloading –induced atrophied muscles should improve rehabilitation strategies. We assessed the effects of stand‐up exercise (SE) training on the recovery of atrophied skeletal muscles in male mice. Mice were trained to stand up and press an elevated lever in response to a light‐tone cue preceding an electric foot shock and then subjected to tail suspension (TS) for 2 weeks to induce disuse atrophy in hind limb muscles. After release from TS, mice were divided into SE‐trained (SE cues: 25 times per set, two sets per day) and non‐SE‐trained groups. Seven days after the training, average myofiber cross‐sectional area (CSA) of the soleus muscle was significantly greater in the SE‐trained group than in the non‐SE‐trained group (1843 ± 194 μm2 vs. 1315 ± 153 μm2). Mean soleus muscle CSA in the SE trained group was not different from that in the CON group subjected to neither TS nor SE training (2005 ± 196 μm2), indicating that SE training caused nearly complete recovery from muscle atrophy. The number of myonuclei per myofiber was increased by ~60% in the SE‐trained group compared with the non‐SE‐trained and CON groups (0.92 ± 0.03 vs. 0.57 ± 0.03 and 0.56 ± 0.11, respectively). The number of proliferating myonuclei, identified by 5‐ethynyl‐2′‐deoxyuridine staining, increased within the first few days of SE training. Thus, it is highly likely that myogenic satellite cells proliferated rapidly in atrophied muscles in response to SE training and fused with existing myofibers to reestablish muscle mass. Stand‐up exercise (SE) training facilitates recovery of myofiber size within 7 days and increases the number of myonuclei during atrophied muscle recovery. This rapid increase in the number of myonuclei derived from myogenic satellite cells may account for the rapid histological changes in atrophied muscles induced by SE training.
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Affiliation(s)
- Yuta Itoh
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan Faculty of Rehabilitation Science, Nagoya Gakuin University, Seto, Japan
| | - Kimihide Hayakawa
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tomohiro Mori
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobuhide Agata
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan Faculty of Health and Medical Sciences, Tokoha University, Hamamatsu, Japan
| | | | - Taro Murakami
- Faculty of Wellness, Sigakkan University, Ohbu, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, Japan Department of Physiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Keisuke Kawakami
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
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