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Xue S, Gao F, Wu X, Xu Q, Weng X, Zhang Q. MUNIX repeatability evaluation method based on FastICA demixing. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2023; 20:16362-16382. [PMID: 37920016 DOI: 10.3934/mbe.2023730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
To enhance the reproducibility of motor unit number index (MUNIX) for evaluating neurological disease progression, this paper proposes a negative entropy-based fast independent component analysis (FastICA) demixing method to assess MUNIX reproducibility in the presence of inter-channel mixing of electromyography (EMG) signals acquired by high-density electrodes. First, composite surface EMG (sEMG) signals were obtained using high-density surface electrodes. Second, the FastICA algorithm based on negative entropy was employed to determine the orthogonal projection matrix that minimizes the negative entropy of the projected signal and effectively separates mixed sEMG signals. Finally, the proposed experimental approach was validated by introducing an interrelationship criterion to quantify independence between adjacent channel EMG signals, measuring MUNIX repeatability using coefficient of variation (CV), and determining motor unit number and size through MUNIX. Results analysis shows that the inclusion of the full (128) channel sEMG information leads to a reduction in CV value by $1.5 \pm 0.1$ and a linear decline in CV value with an increase in the number of channels. The correlation between adjacent channels in participants decreases by $0.12 \pm 0.05$ as the number of channels gradually increases. The results demonstrate a significant reduction in the number of interrelationships between sEMG signals following negative entropy-based FastICA processing, compared to the mixed sEMG signals. Moreover, this decrease in interrelationships becomes more pronounced with an increasing number of channels. Additionally, the CV of MUNIX gradually decreases with an increase in the number of channels, thereby optimizing the issue of abnormal MUNIX repeatability patterns and further enhancing the reproducibility of MUNIX based on high-density surface EMG signals.
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Affiliation(s)
- Suqi Xue
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Farong Gao
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Xudong Wu
- Department of Orthopedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhoushan 316000, China
| | - Qun Xu
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Xuecheng Weng
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Qizhong Zhang
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
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Clark BC. Neural Mechanisms of Age-Related Loss of Muscle Performance and Physical Function. J Gerontol A Biol Sci Med Sci 2023; 78:8-13. [PMID: 36738253 PMCID: PMC10272985 DOI: 10.1093/gerona/glad029] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND This article discusses the putative neural mechanisms of age-related muscle weakness within the broader context of the development of function-promoting therapies for sarcopenia and age-related mobility limitations. We discuss here the evolving definition of sarcopenia and its primary defining characteristic, weakness. METHODS This review explores the premise that impairments in the nervous system's ability to generate maximal force or power contribute to sarcopenia. RESULTS Impairments in neural activation are responsible for a substantial amount of age-related weakness. The neurophysiological mechanisms of weakness are multifactorial. The roles of supraspinal descending command mechanisms, spinal motor neuron firing responsivity, and neuromuscular junction transmission failure in sarcopenia are discussed. Research/clinical gaps and recommendations for future work are highlighted. CONCLUSION Further research is needed to map putative neural mechanisms, determine the clinical relevance of age-related changes in neural activation to sarcopenia, and evaluate the effectiveness of various neurotherapeutic approaches to enhancing physical function.
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Affiliation(s)
- Brian C Clark
- Ohio Musculoskeletal and Neurological Institute (OMNI) and the Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
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Xu Q, Xue S, Gao F, Wu Q, Zhang Q. Evaluation method of motor unit number index based on optimal muscle strength combination. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2023; 20:3854-3872. [PMID: 36899608 DOI: 10.3934/mbe.2023181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Repeatability is an important attribute of motor unit number index (MUNIX) technology. This paper proposes an optimal contraction force combination for MUNIX calculation in an effort to improve the repeatability of this technology. In this study, the surface electromyography (EMG) signals of the biceps brachii muscle of eight healthy subjects were initially recorded with high-density surface electrodes, and the contraction strength was the maximum voluntary contraction force of nine progressive levels. Then, by traversing and comparing the repeatability of MUNIX under various combinations of contraction force, the optimal combination of muscle strength is determined. Finally, calculate MUNIX using the high-density optimal muscle strength weighted average method. The correlation coefficient and the coefficient of variation are utilized to assess repeatability. The results show that when the muscle strength combination is 10, 20, 50 and 70% of the maximum voluntary contraction force, the repeatability of MUNIX is greatest, and the correlation between MUNIX calculated using this combination of muscle strength and conventional methods is high (PCC > 0.99), the repeatability of the MUNIX method improved by 11.5-23.8%. The results indicate that the repeatability of MUNIX differs for various combinations of muscle strength and that MUNIX, which is measured with a smaller number and lower-level contractility, has greater repeatability.
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Affiliation(s)
- Qun Xu
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Suqi Xue
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Farong Gao
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Qiuxuan Wu
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Qizhong Zhang
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
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Verschueren A, Palminha C, Delmont E, Attarian S. Changes in neuromuscular function in elders: Novel techniques for assessment of motor unit loss and motor unit remodeling with aging. Rev Neurol (Paris) 2022; 178:780-787. [PMID: 35863917 DOI: 10.1016/j.neurol.2022.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/08/2022] [Accepted: 03/08/2022] [Indexed: 11/24/2022]
Abstract
Functional muscle fiber denervation is a major contributor to the decline in physical function observed with aging and is now a recognized cause of sarcopenia, a muscle disorder characterized by progressive and generalized degenerative loss of skeletal muscle mass, quality, and strength. There is an interrelationship between muscle strength, motor unit (MU) number, and aging, which suggests that a portion of muscle weakness in seniors may be attributable to the loss of functional MUs. During normal aging, there is a time-related progression of MU loss, an adaptive sprouting followed by a maladaptive sprouting, and continuing recession of terminal Schwann cells leading to a reduced capacity for compensatory reinnervation in elders. In amyotrophic lateral sclerosis, increasing age at onset predicts worse survival ALS and it is possible that age-related depletion of the motor neuron pool may worsen motor neuron disease. MUNE methods are used to estimate the number of functional MU, data from MUNIX arguing for motor neuron loss with aging will be reviewed. Recently, a new MRI technique MU-MRI could be used to assess the MU recruitment or explore the activity of a single MU. This review presents published studies on the changes of neuromuscular function with aging, then focusing on these two novel techniques for assessment of MU loss and MU remodeling.
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Affiliation(s)
- A Verschueren
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France.
| | - C Palminha
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
| | - E Delmont
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
| | - S Attarian
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
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Evans RC, Chen L, Na R, Yoo K, Ran Q. The Gpx4NIKO Mouse Is a Versatile Model for Testing Interventions Targeting Ferroptotic Cell Death of Spinal Motor Neurons. Neurotox Res 2022; 40:373-383. [PMID: 35043381 PMCID: PMC9035057 DOI: 10.1007/s12640-021-00469-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/09/2021] [Accepted: 12/27/2021] [Indexed: 12/13/2022]
Abstract
The degeneration and death of motor neurons lead to motor neuron diseases such as amyotrophic lateral sclerosis (ALS). Although the exact mechanism by which motor neuron degeneration occurs is not well understood, emerging evidence implicates the involvement of ferroptosis, an iron-dependent oxidative mode of cell death. We reported previously that treating Gpx4NIKO mice with tamoxifen to ablate the ferroptosis regulator glutathione peroxidase 4 (GPX4) in neurons produces a severe paralytic model resembling an accelerated form of ALS that appears to be caused by ferroptotic cell death of spinal motor neurons. In this study, in support of the role of ferroptosis in this model, we found that the paralytic symptoms and spinal motor neuron death of Gpx4NIKO mice were attenuated by a chemical inhibitor of ferroptosis. In addition, we observed that the paralytic symptoms of Gpx4NIKO mice were malleable and could be tapered by lowering the dose of tamoxifen, allowing for the generation of a mild paralytic model without a rapid onset of death. We further used both models to evaluate mitochondrial reactive oxygen species (mtROS) in the ferroptosis of spinal motor neurons and showed that overexpression of peroxiredoxin 3, a mitochondrial antioxidant defense enzyme, ameliorated symptoms of the mild but not the severe model of the Gpx4NIKO mice. Our results thus indicate that the Gpx4NIKO mouse is a versatile model for testing interventions that target ferroptotic death of spinal motor neurons in vivo.
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Affiliation(s)
- Robert Cole Evans
- Department of Cell Systems & Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Liuji Chen
- Department of Cell Systems & Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Ren Na
- Department of Cell Systems & Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Kwangsun Yoo
- Department of Cell Systems & Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Qitao Ran
- Department of Cell Systems & Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA.
- Research Service, South Texas Veterans Health Care System, San Antonio, TX, USA.
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Marini M, Tani A, Manetti M, Sgambati E. Overview of sialylation status in human nervous and skeletal muscle tissues during aging. Acta Histochem 2021; 123:151813. [PMID: 34753032 DOI: 10.1016/j.acthis.2021.151813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/29/2021] [Accepted: 10/29/2021] [Indexed: 12/14/2022]
Abstract
Sialic acids (Sias) are a large and heterogeneous family of electronegatively charged nine-carbon monosaccharides containing a carboxylic acid and are mostly found as terminal residues in glycans of glycoproteins and glycolipids such as gangliosides. They are linked to galactose or N-acetylgalactosamine via α2,3 or α2,6 linkage, or to other Sias via α2,8 or more rarely α2,9 linkage, resulting in mono, oligo and polymeric forms. Given their characteristics, Sias play a crucial role in a multitude of human tissue biological processes in physiological and pathological conditions, ranging from development and growth to adult life until aging. Here, we review the sialylation status in human adult life focusing on the nervous and skeletal muscle tissues, which both display significant structural and functional changes during aging, strongly impacting on the whole human body and, therefore, on the quality of life. In particular, this review highlights the fundamental roles played by different types of glycoconjugates Sias in several cellular biological processes in the nervous and skeletal muscle tissues during adult life, also discussing how changes in Sia content during aging may contribute to the physiological decline of physical and nervous functions and to the development of age-related degenerative pathologies. Based on our current knowledge, further in-depth investigations could help to develop novel prophylactic strategies and therapeutic approaches that, by maintaining and/or restoring the correct sialylation status in the nervous and skeletal muscle tissues, could contribute to aging slowing and the prevention of age-related pathologies.
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Jarmusch S, Baber L, Bidlingmaier M, Ferrari U, Hofmeister F, Hintze S, Mehaffey S, Meinke P, Neuerburg C, Schoser B, Tanganelli F, Drey M. Influence of IGF-I serum concentration on muscular regeneration capacity in patients with sarcopenia. BMC Musculoskelet Disord 2021; 22:807. [PMID: 34544407 PMCID: PMC8454138 DOI: 10.1186/s12891-021-04699-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 09/10/2021] [Indexed: 02/01/2023] Open
Abstract
Background Previous research has described a neuroprotective effect of IGF-I, supporting neuronal survival, axon growth and proliferation of muscle cells. Therefore, the association between IGF-I concentration, muscle histology and electrophysiological markers in a cohort of patients with sarcopenia dares investigation. Methods Measurement of serum concentrations of IGF-I and binding partners, electromyographic measurements with the MUNIX (Motor Unit Number Index) method and muscle biopsies were performed in 31 patients with acute hip fracture older age 60 years. Molecular markers for denervation (neural cell adhesion molecule NCAM) and proliferation markers (Ki67) were assessed by immunofluorescence staining of muscle biopsy tissue. Skeletal muscle mass by bioelectrical impedance analysis and hand-grip strength were measured to assess sarcopenia status according to EWGSOP2 criteria. Results Thirty-one patients (20 women) with a mean age of 80.6 ± 7.4 years were included. Concentrations of IGF-I and its binding partners were significantly associated with sarcopenia (ß = − 0.360; p = 0.047) and MUNIX (ß = 0.512; p = 0.005). Further, expression of NCAM (ß = 0.380; p = 0.039) and Ki67 (ß = 0.424; p = 0.022) showed significant associations to IGF-I concentrations. Conclusions The findings suggest a pathogenetic role of IGF-I in sarcopenia based on muscle denervation. Supplementary Information The online version contains supplementary material available at 10.1186/s12891-021-04699-3.
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Affiliation(s)
- Stefanie Jarmusch
- Department of Medicine IV, Geriatrics, University Hospital of LMU Munich, Munich, Germany
| | - Lisa Baber
- Department of Medicine IV, Geriatrics, University Hospital of LMU Munich, Munich, Germany
| | - Martin Bidlingmaier
- Department of Medicine IV, Endocrinological Laboratory, University Hospital of LMU Munich, Munich, Germany
| | - Uta Ferrari
- Department of Medicine IV, Geriatrics, University Hospital of LMU Munich, Munich, Germany
| | - Fabian Hofmeister
- Department of Medicine IV, Geriatrics, University Hospital of LMU Munich, Munich, Germany
| | - Stefan Hintze
- Friedrich-Baur-Institute, Department of Neurology, University Hospital of LMU Munich, Munich, Germany
| | - Stefan Mehaffey
- Department of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital of LMU Munich, Munich, Germany
| | - Peter Meinke
- Friedrich-Baur-Institute, Department of Neurology, University Hospital of LMU Munich, Munich, Germany
| | - Carl Neuerburg
- Department of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital of LMU Munich, Munich, Germany
| | - Benedikt Schoser
- Friedrich-Baur-Institute, Department of Neurology, University Hospital of LMU Munich, Munich, Germany
| | - Fabiana Tanganelli
- Department of Medicine IV, Geriatrics, University Hospital of LMU Munich, Munich, Germany
| | - Michael Drey
- Department of Medicine IV, Geriatrics, University Hospital of LMU Munich, Munich, Germany.
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Head-down tilt bed rest with or without artificial gravity is not associated with motor unit remodeling. Eur J Appl Physiol 2020; 120:2407-2415. [PMID: 32797257 PMCID: PMC7557493 DOI: 10.1007/s00421-020-04458-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 07/31/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE The objective of this study was to assess whether artificial gravity attenuates any long-duration head-down 60 bed rest (HDBR)-induced alterations in motor unit (MU) properties. METHODS Twenty-four healthy participants (16 men; 8 women; 26-54 years) underwent 60-day HDBR with (n = 16) or without (n = 8) 30 min artificial gravity daily induced by whole-body centrifugation. Compound muscle action potential (CMAP), MU number (MUNIX) and MU size (MUSIX) were estimated using the method of Motor Unit Number Index in the Abductor digiti minimi and tibialis anterior muscles 5 days before (BDC-5), and during day 4 (HDT4) and 59 (HDT59) of HDBR. RESULTS The CMAP, MUNIX, and MUSIX at baseline did not change significantly in either muscle, irrespective of the intervention (p > 0.05). Across groups, there were no significant differences in any variable during HDBR, compared to BDC-5. CONCLUSION Sixty days of HDBR with or without artificial gravity does not induce alterations in motor unit number and size in the ADM or TA muscles in healthy individuals.
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Tahmaz M, Yoon M, Schellinger PD, Philipps J. Cross‐sectional area in median and ulnar nerve ultrasound correlates with hand volume. Muscle Nerve 2020; 62:83-88. [DOI: 10.1002/mus.26881] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 04/03/2020] [Accepted: 04/05/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Melis Tahmaz
- Department of Neurology and Neurogeriatrics Ruhr‐University Bochum, Johannes‐Wesling‐Klinikum Minden, UK RUB Minden Germany
| | - Min‐Suk Yoon
- Department of Neurology Evangelisches Krankenhaus Hattingen gGmbH Hattingen Germany
| | - Peter D. Schellinger
- Department of Neurology and Neurogeriatrics Ruhr‐University Bochum, Johannes‐Wesling‐Klinikum Minden, UK RUB Minden Germany
| | - Jörg Philipps
- Department of Neurology and Neurogeriatrics Ruhr‐University Bochum, Johannes‐Wesling‐Klinikum Minden, UK RUB Minden Germany
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Kang H, Tian L, Thompson WJ. Schwann cell guidance of nerve growth between synaptic sites explains changes in the pattern of muscle innervation and remodeling of synaptic sites following peripheral nerve injuries. J Comp Neurol 2019; 527:1388-1400. [PMID: 30620049 DOI: 10.1002/cne.24625] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 01/14/2023]
Abstract
Terminal Schwann cells (SCs) are nonmyelinating glia that are a prominent component of the neuromuscular junction (NMJ) where motor neurons form synapses onto muscle fibers. These cells play important roles not only in development and maintenance of the neuromuscular synapse but also restoring synaptic function after nerve damage. In response to muscle denervation, terminal SCs undergo dramatic changes in their gene expression patterns as well as in their morphology, such as extending elaborate processes into inter-junctional space. These SC processes serve as a path to guide axon terminal sprouts from nearby innervated junctions, promoting rapid reinnervation of denervated fibers. We studied the role of terminal SCs in synapse reformation by using two different fluorescent proteins to simultaneously label motor axons and SCs; we examined these junctions repeatedly in living animals using a fluorescence microscope. Here, we show that alterations in the patterns of muscle innervation following recovery from nerve injury can be explained by SC guidance of regenerating axons. In turn, this guidance leads to remodeling of the NMJ itself.
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Affiliation(s)
- Hyuno Kang
- Section of Molecular Cell and Developmental Biology, The University of Texas at Austin, Austin, Texas.,Gwangju Center, Korea Basic Science Institute, Gwangju, South Korea
| | - Le Tian
- Section of Molecular Cell and Developmental Biology, The University of Texas at Austin, Austin, Texas
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12
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Morley JE. Editorial: Bidirectional Communication Between Brain and Muscle. J Nutr Health Aging 2018; 22:1144-1145. [PMID: 30498818 DOI: 10.1007/s12603-018-1141-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- J E Morley
- John E. Morley, MB,BCh, Division of Geriatric Medicine, Saint Louis University School of Medicine, 1402 S. Grand Blvd., M238, St. Louis, MO 63104,
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Scicchitano BM, Pelosi L, Sica G, Musarò A. The physiopathologic role of oxidative stress in skeletal muscle. Mech Ageing Dev 2017; 170:37-44. [PMID: 28851603 DOI: 10.1016/j.mad.2017.08.009] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/14/2017] [Accepted: 08/18/2017] [Indexed: 12/16/2022]
Abstract
Muscle senescence is a complex mechanism that is usually associated with a decrease in mass, strength and velocity of contraction. This state, known as sarcopenia, is a multifactorial process and it may be the consequence of several events, including accumulation of oxidative stress. The role of oxidative stress in the physiopathology of skeletal muscle is quite complex. Transiently increased levels of oxidative stress might reflect a potentially health promoting process, while an uncontrolled accumulation might have pathological implication. The physiopathological role of oxidative stress on skeletal muscle, its involvement in aging-induced sarcopenia, and potential countermeasures will be discussed.
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Affiliation(s)
- Bianca Maria Scicchitano
- Institute of Histology and Embryology, School of Medicine, Catholic University of the Sacred Heart, Rome, Italy.
| | - Laura Pelosi
- DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Italy
| | - Gigliola Sica
- Institute of Histology and Embryology, School of Medicine, Catholic University of the Sacred Heart, Rome, Italy
| | - Antonio Musarò
- DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Italy; Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Italy.
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Neuwirth C, Burkhardt C, Weber M. Motor unit number index in the nasalis muscle in healthy subjects and patients with amyotrophic lateral sclerosis. Muscle Nerve 2016; 54:733-7. [PMID: 26970219 DOI: 10.1002/mus.25100] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 02/25/2016] [Accepted: 03/03/2016] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Motor unit number index (MUNIX) is a quick and feasible electrophysiological technique that estimates the number of motor neurons in limb muscles in healthy and amyotrophic lateral sclerosis (ALS) subjects. In this study we explored the feasibility, reliability, and differences of MUNIX in nasalis muscles in healthy subjects and ALS patients. METHODS MUNIX of the nasalis muscle of 50 healthy and 20 ALS subjects with bulbar involvement was compared. Functional impairment was evaluated by the ALS Functional Rating Scale-Revised and its bulbar subscore. RESULTS MUNIX was well tolerated and quickly performed. Bulbar ALS patients showed non-significant lower nasalis MUNIX values and a lower functional bulbar subscore. Intra- and interrater reliability showed high intraclass correlation coefficients (ICCs) in healthy subjects (0.87) and ALS patients (0.92). CONCLUSION MUNIX of the nasalis muscle is a reproducible method, but it showed no significant difference between healthy and bulbar ALS subjects and seems not to be a useful marker of disease progression in ALS. Muscle Nerve 54: 733-737, 2016.
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Affiliation(s)
- Christoph Neuwirth
- Neuromuscular Diseases Centre, ALS Clinic, Kantonsspital St. Gallen, Rorschacherstrasse 95, CH-9007, St. Gallen, Switzerland.
| | - Christian Burkhardt
- Neuromuscular Diseases Centre, ALS Clinic, Kantonsspital St. Gallen, Rorschacherstrasse 95, CH-9007, St. Gallen, Switzerland
| | - Markus Weber
- Neuromuscular Diseases Centre, ALS Clinic, Kantonsspital St. Gallen, Rorschacherstrasse 95, CH-9007, St. Gallen, Switzerland
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Zhou P, Li X, Li S, Nandedkar SD. A dilemma in stroke application: Standard or modified motor unit number index? Clin Neurophysiol 2016; 127:2756-2759. [PMID: 27417048 DOI: 10.1016/j.clinph.2016.05.185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 04/25/2016] [Accepted: 05/16/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Ping Zhou
- Guangdong Provincial Work Injury Rehabilitation Center, Guangzhou, China; Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston and TIRR Memorial Hermann Research Center, Houston, TX, USA.
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston and TIRR Memorial Hermann Research Center, Houston, TX, USA
| | - Sheng Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston and TIRR Memorial Hermann Research Center, Houston, TX, USA
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Sanchez GN, Sinha S, Liske H, Chen X, Nguyen V, Delp SL, Schnitzer MJ. In Vivo Imaging of Human Sarcomere Twitch Dynamics in Individual Motor Units. Neuron 2016; 88:1109-1120. [PMID: 26687220 DOI: 10.1016/j.neuron.2015.11.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/28/2015] [Accepted: 11/10/2015] [Indexed: 12/14/2022]
Abstract
Motor units comprise a pre-synaptic motor neuron and multiple post-synaptic muscle fibers. Many movement disorders disrupt motor unit contractile dynamics and the structure of sarcomeres, skeletal muscle's contractile units. Despite the motor unit's centrality to neuromuscular physiology, no extant technology can image sarcomere twitch dynamics in live humans. We created a wearable microscope equipped with a microendoscope for minimally invasive observation of sarcomere lengths and contractile dynamics in any major skeletal muscle. By electrically stimulating twitches via the microendoscope and visualizing the sarcomere displacements, we monitored single motor unit contractions in soleus and vastus lateralis muscles of healthy individuals. Control experiments verified that these evoked twitches involved neuromuscular transmission and faithfully reported muscle force generation. In post-stroke patients with spasticity of the biceps brachii, we found involuntary microscopic contractions and sarcomere length abnormalities. The wearable microscope facilitates exploration of many basic and disease-related neuromuscular phenomena never visualized before in live humans.
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Affiliation(s)
- Gabriel N Sanchez
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Supriyo Sinha
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Holly Liske
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Xuefeng Chen
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Viet Nguyen
- Department of Neurology, Stanford University, Stanford, CA 94305, USA
| | - Scott L Delp
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
| | - Mark J Schnitzer
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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17
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Abstract
Sarcopenia is now clinically defined as a loss of muscle mass coupled with functional deterioration (either walking speed or distance or grip strength). Based on the FRAX studies suggesting that the questions without bone mineral density can be used to screen for osteoporosis, there is now a valid simple questionnaire to screen for sarcopenia, i.e., the SARC-F. Numerous factors have been implicated in the pathophysiology of sarcopenia. These include genetic factors, mitochondrial defects, decreased anabolic hormones (e.g., testosterone, vitamin D, growth hormone and insulin growth hormone-1), inflammatory cytokine excess, insulin resistance, decreased protein intake and activity, poor blood flow to muscle and deficiency of growth derived factor-11. Over the last decade, there has been a remarkable increase in our understanding of the molecular biology of muscle, resulting in a marked increase in potential future targets for the treatment of sarcopenia. At present, resistance exercise, protein supplementation, and vitamin D have been established as the basic treatment of sarcopenia. High-dose testosterone increases muscle power and function, but has a number of potentially limiting side effects. Other drugs in clinical development include selective androgen receptor molecules, ghrelin agonists, myostatin antibodies, activin IIR antagonists, angiotensin converting enzyme inhibitors, beta antagonists, and fast skeletal muscle troponin activators. As sarcopenia is a major predictor of frailty, hip fracture, disability, and mortality in older persons, the development of drugs to treat it is eagerly awaited.
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Affiliation(s)
- John E Morley
- Division of Geriatric Medicine, Saint Louis University School of Medicine, 1402 S. Grand Blvd., M238, St. Louis, MO, 63104, USA.
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18
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Scherbakov N, Knops M, Ebner N, Valentova M, Sandek A, Grittner U, Dahinden P, Hettwer S, Schefold JC, von Haehling S, Anker SD, Joebges M, Doehner W. Evaluation of C-terminal Agrin Fragment as a marker of muscle wasting in patients after acute stroke during early rehabilitation. J Cachexia Sarcopenia Muscle 2016; 7:60-7. [PMID: 27066319 PMCID: PMC4799857 DOI: 10.1002/jcsm.12068] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 07/15/2015] [Accepted: 07/31/2015] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND C-terminal Agrin Fragment (CAF) has been proposed as a novel biomarker for sarcopenia originating from the degeneration of the neuromuscular junctions. In patients with stroke muscle wasting is a common observation that predicts functional outcome. We aimed to evaluate agrin sub-fragment CAF22 as a marker of decreased muscle mass and physical performance in the early phase after acute stroke. METHODS Patients with acute ischaemic or haemorrhagic stroke (n = 123, mean age 70 ± 11 y, body mass index BMI 27.0 ± 4.9 kg/m(2)) admitted to inpatient rehabilitation were studied in comparison to 26 healthy controls of similar age and BMI. Functional assessments were performed at begin (23 ± 17 days post stroke) and at the end of the structured rehabilitation programme (49 ± 18 days post stroke) that included physical assessment, maximum hand grip strength, Rivermead motor assessment, and Barthel index. Body composition was assessed by bioelectrical impedance analysis (BIA). Serum levels of CAF22 were measured by ELISA. RESULTS CAF22 levels were elevated in stroke patients at admission (134.3 ± 52.3 pM) and showed incomplete recovery until discharge (118.2 ± 42.7 pM) compared to healthy controls (95.7 ± 31.8 pM, p < 0.001). Simple regression analyses revealed an association between CAF22 levels and parameters of physical performance, hand grip strength, and phase angle, a BIA derived measure of the muscle cellular integrity. Improvement of the handgrip strength of the paretic arm during rehabilitation was independently related to the recovery of CAF22 serum levels only in those patients who showed increased lean mass during the rehabilitation. CONCLUSIONS CAF22 serum profiles showed a dynamic elevation and recovery in the subacute phase after acute stroke. Further studies are needed to explore the potential of CAF22 as a serum marker to monitor the muscle status in patients after stroke.
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Affiliation(s)
- Nadja Scherbakov
- Center for Stroke Research CSB Charite Universitätsmedizin Berlin Germany; German Centre for Cardiovascular Research (DZHK), partner site Berlin Germany
| | - Michael Knops
- Center for Stroke Research CSB Charite Universitätsmedizin Berlin Germany
| | - Nicole Ebner
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany
| | - Miroslava Valentova
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany; 1st Department of Internal Medicine Comenius University Bratislava Slovak Republic
| | - Anja Sandek
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany
| | - Ulrike Grittner
- Center for Stroke Research CSB Charite Universitätsmedizin Berlin Germany
| | | | | | - Jörg C Schefold
- Department of Intensive Care Medicine Inselspital, University Hospital of Bern Switzerland
| | - Stephan von Haehling
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany
| | - Stefan D Anker
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany
| | | | - Wolfram Doehner
- Center for Stroke Research CSB Charite Universitätsmedizin Berlin Germany; German Centre for Cardiovascular Research (DZHK), partner site Berlin Germany; Department of Cardiology Charite Universitätsmedizin Berlin Germany
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19
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Piasecki M, Ireland A, Jones DA, McPhee JS. Age-dependent motor unit remodelling in human limb muscles. Biogerontology 2015; 17:485-96. [PMID: 26667009 PMCID: PMC4889636 DOI: 10.1007/s10522-015-9627-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/26/2015] [Indexed: 12/14/2022]
Abstract
Voluntary control of skeletal muscle enables humans to interact with and manipulate the environment. Lower muscle mass, weakness and poor coordination are common complaints in older age and reduce physical capabilities. Attention has focused on ways of maintaining muscle size and strength by exercise, diet or hormone replacement. Without appropriate neural innervation, however, muscle cannot function. Emerging evidence points to a neural basis of muscle loss. Motor unit number estimates indicate that by age around 71 years, healthy older people have around 40 % fewer motor units. The surviving low- and moderate-threshold motor units recruited for moderate intensity contractions are enlarged by around 50 % and show increased fibre density, presumably due to collateral reinnervation of denervated fibres. Motor unit potentials show increased complexity and the stability of neuromuscular junction transmissions is decreased. The available evidence is limited by a lack of longitudinal studies, relatively small sample sizes, a tendency to examine the small peripheral muscles and relatively few investigations into the consequences of motor unit remodelling for muscle size and control of movements in older age. Loss of motor neurons and remodelling of surviving motor units constitutes the major change in ageing muscles and probably contributes to muscle loss and functional impairments. The deterioration and remodelling of motor units likely imposes constraints on the way in which the central nervous system controls movements.
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Affiliation(s)
- Mathew Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - Alex Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - David A Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - Jamie S McPhee
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK.
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20
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Li X, Nandedkar SD, Zhou P. Modified motor unit number index: A simulation study of the first dorsal interosseous muscle. Med Eng Phys 2015; 38:115-20. [PMID: 26639774 DOI: 10.1016/j.medengphy.2015.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 10/23/2015] [Accepted: 11/06/2015] [Indexed: 12/14/2022]
Abstract
The motor unit number index (MUNIX) technique has provided a quick and convenient approach to estimating motor unit population changes in a muscle. Reduction in motor unit action potential (MUAP) amplitude can lead to underestimation of motor unit numbers using the standard MUNIX technique. This study aims to overcome this limitation by developing a modified MUNIX (mMUNIX) technique. The mMUNIX uses a variable that is associated with the area of compound muscle action potential (CMAP) rather than an arbitrary fixed value (20 mV ms) as used in the standard MUNIX to define the output. The performance of the mMUNIX was evaluated using motoneuron pool and surface electromyography (EMG) models. With a fixed motor unit number, the mMUNIX output remained relatively constant with varying degrees of MUAP amplitude changes, while the standard MUNIX substantially underestimated the motor unit number in such cases. However, when MUAP amplitude remained unchanged, the mMUNIX showed less sensitivity than the standard MUNIX in tracking motor unit loss. The current simulation study demonstrated both the advantages and limitations of the standard and modified MUNIX techniques, which can help guide appropriate application and interpretation of MUNIX measurements.
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Affiliation(s)
- Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, 1333B Moursund St., Houston, TX, USA; TIRR Memorial Hermann Research Center, Houston, TX, USA.
| | | | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, 1333B Moursund St., Houston, TX, USA; TIRR Memorial Hermann Research Center, Houston, TX, USA; Guangdong Work Injury Rehabilitation Center, Guangzhou, China
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21
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Li X, He W, Li C, Wang YC, Slavens BA, Zhou P. Motor unit number index examination in dominant and non-dominant hand muscles. Laterality 2015; 20:699-710. [PMID: 26227495 DOI: 10.1080/1357650x.2015.1041971] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This study investigated the effect of handedness on motor unit number index (MUNIX). Maximal hand strength, compound muscle action potential (CMAP) and voluntary surface electromyography (EMG) signals were measured bilaterally for the first dorsal interosseous (FDI) and thenar muscles in 24 right-handed and 2 left-handed healthy subjects. Mean (±standard error) grip and pinch forces in the dominant hand were 43.99 ± 2.36 kg and 9.36 ± 0.52 kg respectively, significantly larger than those in the non-dominant hand (grip: 41.37 ± 2.29 kg, p < .001; pinch: 8.79 ± 0.46 kg, p < .01). Examination of myoelectric parameters did not show a significant difference among the CMAP area, the MUNIX or motor unit size index (MUSIX) between the two sides in the FDI and thenar muscles. In addition, there was a lack of correlation between the strength and myoelectric parameters in regression analysis. However, strong correlations were observed between dominant and non-dominant hand muscles in both strength and myoelectric measures. Our results indicate that the population of motor units or spinal motor neurons as estimated from MUNIX may not be associated with handedness. Such findings help understand and interpret the MUNIX during its application for clinical or laboratory investigations.
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Affiliation(s)
- Xiaoyan Li
- a Department of Physical Medicine and Rehabilitation , University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center , Houston , TX , USA
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22
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Boccia G, Dardanello D, Coratella G, Rinaldo N, Schena F, Rainoldi A. Differences in age-related fiber atrophy between vastii muscles of active subjects: a multichannel surface EMG study. Physiol Meas 2015; 36:1591-600. [DOI: 10.1088/0967-3334/36/7/1591] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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23
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Li L, Li X, Liu J, Zhou P. Alterations in multidimensional motor unit number index of hand muscles after incomplete cervical spinal cord injury. Front Hum Neurosci 2015; 9:238. [PMID: 26005410 PMCID: PMC4424856 DOI: 10.3389/fnhum.2015.00238] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 04/13/2015] [Indexed: 12/13/2022] Open
Abstract
The objective of this study was to apply a novel multidimensional motor unit number index (MD-MUNIX) technique to examine hand muscles in patients with incomplete cervical spinal cord injury (SCI). The MD-MUNIX was estimated from the compound muscle action potential (CMAP) and different levels of surface interference pattern electromyogram (EMG) at multiple directions of voluntary isometric muscle contraction. The MD-MUNIX was applied in the first dorsal interosseous (FDI), thenar and hypothenar muscles of SCI (n = 12) and healthy control (n = 12) subjects. The results showed that the SCI subjects had significantly smaller CMAP and MD-MUNIX in all the three examined muscles, compared to those derived from the healthy control subjects. The multidimensional motor unit size index (MD-MUSIX) demonstrated significantly larger values for the FDI and hypothenar muscles in SCI subjects than those from healthy control subjects, whereas the MD-MUSIX enlargement was marginally significant for the thenar muscles. The findings from the MD-MUNIX analyses provide an evidence of motor unit loss in hand muscles of cervical SCI patients, contributing to hand function deterioration.
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Affiliation(s)
- Le Li
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-Sen University Guangzhou, China ; Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA
| | - Jie Liu
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago Chicago, IL, USA
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA ; Biomedical Engineering Program, University of Science and Technology of China Hefei, China
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24
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Stroke-Related Sarcopenia: Specific Characteristics. J Am Med Dir Assoc 2015; 16:272-6. [DOI: 10.1016/j.jamda.2014.12.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 12/25/2022]
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25
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Marciniak C, Li X, Zhou P. An examination of motor unit number index in adults with cerebral palsy. J Electromyogr Kinesiol 2015; 25:444-50. [PMID: 25840713 DOI: 10.1016/j.jelekin.2015.02.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 01/22/2015] [Accepted: 02/13/2015] [Indexed: 12/14/2022] Open
Abstract
Spinal motor neuron loss may be a factor contributing to weakness in central disorders. The aim of this study was to assess whether motor unit numbers are reduced in the hand musculature of adults with cerebral palsy (CP) using the motor unit number index (MUNIX) technique. In this prospective, case-control study, 10 adults with CP were matched with healthy controls. MUNIX was computed using area and power of voluntary surface hypothenar electromyographic (EMG) signals and the compound muscle action potential (CMAP) recorded with ulnar nerve stimulation. The motor unit size index (MUSIX) was calculated based on maximum CMAP amplitude and MUNIX value. Gross Motor Function Classification Scale (GMFCS) and Manual Abilities Classification Scale (MACS) levels were rated for CP subjects. MUNIX was significantly lower for CP participants (Mean 167.8 vs. 214.4, p=.022). MUNIX values did not correlate with GMFCS or MACS. MUSIX values were higher, though not significantly, for CP subjects (p=.11). MUSIX increased with increasing MACS levels (r(2)=.4017, p=.049). Thus, motor unit numbers in ulnar hand muscles may be decreased with CP. MUSIX values are associated with greater hand impairment. Therefore, peripheral motor unit loss as a component of the weakness found with CP deserves further evaluation.
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Affiliation(s)
- Christina Marciniak
- Department of Physical Medicine and Rehabilitation and the Department of Neurology, Northwestern University Feinberg Medical School and the Rehabilitation Institute of Chicago.
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, and TIRR Memorial Hermann Research Center, Houston, TX 77030, USA
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, and TIRR Memorial Hermann Research Center, Houston, TX 77030, USA; Biomedical Engineering Program, University of Science and Technology of China, Hefei, 230027, China
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26
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Ogborn DI, McKay BR, Crane JD, Safdar A, Akhtar M, Parise G, Tarnopolsky MA. Effects of age and unaccustomed resistance exercise on mitochondrial transcript and protein abundance in skeletal muscle of men. Am J Physiol Regul Integr Comp Physiol 2015; 308:R734-41. [PMID: 25695287 DOI: 10.1152/ajpregu.00005.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 02/13/2015] [Indexed: 01/07/2023]
Abstract
Mitochondrial dysfunction may contribute to age-associated muscle atrophy. Previous data has shown that resistance exercise (RE) increases mitochondrial gene expression and enzyme activity in older adults; however, the acute response to RE has not been well characterized. To characterize the acute mitochondrial response to unaccustomed RE, healthy young (21 ± 3 yr) and older (70 ± 4 yr) men performed a unilateral RE bout for the knee extensors. Muscle biopsies were taken at rest and 3, 24, and 48 h following leg press and knee extension exercise. The expression of the mitochondrial transcriptional regulator proliferator-activated receptor γ coactivator 1-α (PGC-1α) mRNA was increased at 3 h postexercise; however, all other mitochondrial variables decreased over the postexercise period, irrespective of age. ND1, ND4, and citrate synthase (CS) mRNA were all lower at 48 h postexercise, along with specific protein subunits of complex II, III, IV, and ATP synthase. Mitochondrial DNA (mtDNA) copy number decreased by 48 h postexercise, and mtDNA deletions were higher in the older adults and remained unaffected by acute exercise. Elevated mitophagy could not explain the reduction in mitochondrial proteins and DNA, because there was no increase in ubiquitinated voltage-dependent anion channel (VDAC) or its association with PTEN-induced putative kinase 1 (Pink1) or Parkin, and elevated p62 content indicated an impairment or reduction in autophagocytic flux. In conclusion, age did not influence the response of specific mitochondrial transcripts, proteins, and DNA to a bout of RE.
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Affiliation(s)
| | | | | | - Adeel Safdar
- Cardiovascular Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachussets
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27
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The effects of testosterone and insulin-like growth factor 1 on motor system form and function. Exp Gerontol 2015; 64:81-6. [PMID: 25681641 DOI: 10.1016/j.exger.2015.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 01/31/2015] [Accepted: 02/10/2015] [Indexed: 12/25/2022]
Abstract
In this perspective article, we review the effects of selected anabolic hormones on the motoric system and speculate on the role these hormones may have on influencing muscle and physical function via their impact on the nervous system. Both muscle strength and anabolic hormone levels decline around middle age into old age over a similar time period, and several animal and human studies indicate that exogenously increasing anabolic hormones (e.g., testosterone and insulin-like growth factor-1 (IGF-1)) in aged subjects is positively associated with improved muscle strength. While most studies in humans have focused on the effects of anabolic hormones on muscle growth, few have considered the impact these hormones have on the motoric system. However, data from animals demonstrate that administering either testosterone or IGF-1 to cells of the central and peripheral motor system can increase cell excitability, attenuate atrophic changes, and improve regenerative capacity of motor neurons. While these studies do not directly indicate that changes in anabolic hormones contribute to reduced human performance in the elderly (e.g., muscle weakness and physical limitations), they do suggest that additional research is warranted along these lines.
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28
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Boccia G, Dardanello D, Rosso V, Pizzigalli L, Rainoldi A. The Application of sEMG in Aging: A Mini Review. Gerontology 2014; 61:477-84. [DOI: 10.1159/000368655] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/24/2014] [Indexed: 11/19/2022] Open
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29
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Drey M, Sieber CC, Degens H, McPhee J, Korhonen MT, Müller K, Ganse B, Rittweger J. Relation between muscle mass, motor units and type of training in master athletes. Clin Physiol Funct Imaging 2014; 36:70-6. [DOI: 10.1111/cpf.12195] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/09/2014] [Indexed: 12/14/2022]
Affiliation(s)
- Michael Drey
- Institute for Biomedicine of Ageing; University of Erlangen-Nürnberg; Nürnberg Germany
| | - Cornel C. Sieber
- Institute for Biomedicine of Ageing; University of Erlangen-Nürnberg; Nürnberg Germany
| | - Hans Degens
- School of Healthcare Science; Manchester Metropolitan University; Manchester UK
| | - Jamie McPhee
- School of Healthcare Science; Manchester Metropolitan University; Manchester UK
| | - Marko T. Korhonen
- Gerontology Research Center; Department of Health Sciences; University of Jyväskylä; Jyväskylä Finland
| | - Klaus Müller
- German Aerospace Center; Institute of Aerospace Medicine; Cologne Germany
| | - Bergita Ganse
- German Aerospace Center; Institute of Aerospace Medicine; Cologne Germany
| | - Jörn Rittweger
- German Aerospace Center; Institute of Aerospace Medicine; Cologne Germany
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30
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Alway SE, Myers MJ, Mohamed JS. Regulation of satellite cell function in sarcopenia. Front Aging Neurosci 2014; 6:246. [PMID: 25295003 PMCID: PMC4170136 DOI: 10.3389/fnagi.2014.00246] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/01/2014] [Indexed: 01/08/2023] Open
Abstract
The mechanisms contributing to sarcopenia include reduced satellite cell (myogenic stem cell) function that is impacted by the environment (niche) of these cells. Satellite cell function is affected by oxidative stress, which is elevated in aged muscles, and this along with changes in largely unknown systemic factors, likely contribute to the manner in which satellite cells respond to stressors such as exercise, disuse, or rehabilitation in sarcopenic muscles. Nutritional intervention provides one therapeutic strategy to improve the satellite cell niche and systemic factors, with the goal of improving satellite cell function in aging muscles. Although many elderly persons consume various nutraceuticals with the hope of improving health, most of these compounds have not been thoroughly tested, and the impacts that they might have on sarcopenia and satellite cell function are not clear. This review discusses data pertaining to the satellite cell responses and function in aging skeletal muscle, and the impact that three compounds: resveratrol, green tea catechins, and β-Hydroxy-β-methylbutyrate have on regulating satellite cell function and therefore contributing to reducing sarcopenia or improving muscle mass after disuse in aging. The data suggest that these nutraceutical compounds improve satellite cell function during rehabilitative loading in animal models of aging after disuse (i.e., muscle regeneration). While these compounds have not been rigorously tested in humans, the data from animal models of aging provide a strong basis for conducting additional focused work to determine if these or other nutraceuticals can offset the muscle losses, or improve regeneration in sarcopenic muscles of older humans via improving satellite cell function.
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Affiliation(s)
- Stephen E. Alway
- Laboratory of Muscle Biology and Sarcopenia, Department of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- West Virginia Clinical and Translational Science Institute, Morgantown, WV, USA
- Center for Cardiovascular and Respiratory Sciences, Morgantown, WV, USA
| | - Matthew J. Myers
- Laboratory of Muscle Biology and Sarcopenia, Department of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Junaith S. Mohamed
- Laboratory of Muscle Biology and Sarcopenia, Department of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
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31
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Zhou P, Nandedkar SD, Barkhaus PE. Voluntary Contraction Direction Dependence of Motor Unit Number Index in Patients with Amyotrophic Lateral Sclerosis. IEEE Trans Neural Syst Rehabil Eng 2014; 22:992-6. [DOI: 10.1109/tnsre.2014.2314391] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Jenkins ND, Buckner SL, Cochrane KC, Bergstrom HC, Palmer TB, Johnson GO, Schmidt RJ, Housh TJ, Cramer JT. Age-related differences in rates of torque development and rise in EMG are eliminated by normalization. Exp Gerontol 2014; 57:18-28. [DOI: 10.1016/j.exger.2014.04.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/22/2014] [Accepted: 04/28/2014] [Indexed: 11/24/2022]
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Li X, Liu J, Li S, Wang YC, Zhou P. Examination of hand muscle activation and motor unit indices derived from surface EMG in chronic stroke. IEEE Trans Biomed Eng 2014; 61:2891-8. [PMID: 24967982 DOI: 10.1109/tbme.2014.2333034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this study, we used muscle and motor unit indices, derived from convenient surface electromyography (EMG) measurements, for examination of paretic muscle changes post stroke. For 12 stroke subjects, compound muscle action potential and voluntary surface EMG signals were recorded from paretic and contralateral first dorsal interosseous, abductor pollicis brevis, and abductor digiti minimi muscles. Muscle activation index (AI), motor unit number index (MUNIX), and motor unit size index (MUSIX) were then calculated for each muscle. There was a significant AI reduction for all the three muscles in paretic side compared with contralateral side, providing an evidence of muscle activation deficiency after stroke. The hand MUNIX (defined by summing the values from the three muscles) was significantly reduced in paretic side compared with contralateral side, whereas the hand MUSIX was not significantly different. Furthermore, diverse changes in MUNIX and MUSIX were observed from the three muscles. A major feature of the present examinations is the primary reliance on surface EMG, which offers practical benefits because it is noninvasive, induces minimal discomfort and can be performed quickly.
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Expression of sialic acids in human adult skeletal muscle tissue. Acta Histochem 2014; 116:926-35. [PMID: 24703356 DOI: 10.1016/j.acthis.2014.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 03/06/2014] [Accepted: 03/11/2014] [Indexed: 12/20/2022]
Abstract
Investigations mostly in animal models have shown a role of sialic acid in the morphology and functionality of skeletal muscle during development and adult life. Several studies in humans have been performed regarding changes in sialic acid expression in a particular pathology, hereditary inclusion body myopathy, leading to muscular weakness and atrophy, with a similar phenomenon appearing also in sarcopenia of aging. In this study the expression of monomeric and polymeric sialic acids was evaluated in human skeletal muscle during adult life. Surgical biopsies of the Quadriceps femoris muscle from men aged 18-25 years (young group; n=8) and men aged 72-78 (elderly group; n=10) were collected for analysis. Expression of sialic acids was evaluated using lectin histochemistry, associated with enzymatic and chemical treatments to characterize monomeric and polymeric sialic acids. The polysialic acid expression was also evaluated by immunohistochemistry. Various types of sialic acid in the muscle tissue, in different amounts in the study groups, were detected. Monomeric sialic acids decreased in the elderly group compared with the young group, whereas polysialic acid increased. Sialic acid acetylation was present only in the young group. These findings demonstrated that changes in the expression of sialic acids in skeletal muscle tissue may be related to morphofunctional modifications occurring during aging.
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Motoneuron Loss Is Associated With Sarcopenia. J Am Med Dir Assoc 2014; 15:435-9. [DOI: 10.1016/j.jamda.2014.02.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/30/2014] [Accepted: 02/04/2014] [Indexed: 12/14/2022]
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Kaya RD, Nakazawa M, Hoffman RL, Clark BC. Interrelationship between muscle strength, motor units, and aging. Exp Gerontol 2013; 48:920-5. [PMID: 23832080 PMCID: PMC3750065 DOI: 10.1016/j.exger.2013.06.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/24/2013] [Accepted: 06/27/2013] [Indexed: 12/14/2022]
Abstract
The interrelationship between muscle strength, motor unit (MU) number, and age is poorly understood, and in this study we sought to determine whether age-related differences in muscle strength are moderated by estimates of functioning MU number and size. Eighteen older adults (OA; 67 ± 1.20 years) and 24 young adults (YA; 22 ± 0.74 years) participated in this study. Maximum voluntary pinch-grip strength of the nondominant hand was determined and estimates of MU number were obtained from the abductor pollicis brevis muscle using the noninvasive motor unit number index (MUNIX) technique. The MUNIX technique was also utilized to derive a motor unit size index (MUSIX). An analysis of covariance (Age Group × MUNIX or MUSIX) was used to test heterogeneity of regression slopes, with body mass and gender serving as covariates. We observed that the slope of pinch-grip strength on the estimated number of MUs between YA and OA differed, indicated by an Age Group × MUNIX interaction (p = 0.04). Specifically, after controlling for the effect of body mass and gender, the slope in OA was significantly positive (0.14 ± 0.06 N/MUs, p = 0.03), whereas no such relationship was found in YA (-0.08 ± 0.09 N/MUs, p = 0.35). A significant Age Group × MUSIX interaction was also observed for strength (p < 0.01). In contrast to MUNIX, the slope in younger adults was significantly positive (0.48 ± 0.11 N/μV, p < 0.01), whereas no such relationship was found in older adults (-0.30 ± 0.22 N/μV, p = 0.18). These findings indicate that there is an interrelationship between muscle strength, MU numbers, and aging, which suggests that a portion of muscle weakness in seniors may be attributable to the loss of functioning motor units.
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Affiliation(s)
- Ryan D. Kaya
- Ohio Musculoskeletal & Neurological Institute (OMNI), Ohio University, Athens, OH USA
- School of Applied Health and Wellness, Ohio University, Athens, OH USA
| | - Masato Nakazawa
- Ohio Musculoskeletal & Neurological Institute (OMNI), Ohio University, Athens, OH USA
- Office of Research and Grants, Ohio University, Athens, OH USA
| | - Richard L. Hoffman
- Ohio Musculoskeletal & Neurological Institute (OMNI), Ohio University, Athens, OH USA
- Department of Biomedical Sciences, Ohio University, Athens, OH USA
| | - Brian C. Clark
- Ohio Musculoskeletal & Neurological Institute (OMNI), Ohio University, Athens, OH USA
- Department of Biomedical Sciences, Ohio University, Athens, OH USA
- Department of Geriatric Medicine and Gerontology at Ohio University, Athens, OH USA
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