101
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Affiliation(s)
- Russell T. Hepple
- Department of Physical TherapyDepartment of Physiology & Functional Genomics, Institute of Aging, and Myology InstituteUniversity of FloridaGainesvilleFLUSA
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102
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Kelly NA, Hammond KG, Bickel CS, Windham ST, Tuggle SC, Bamman MM. Effects of aging and Parkinson's disease on motor unit remodeling: influence of resistance exercise training. J Appl Physiol (1985) 2018; 124:888-898. [PMID: 29357501 PMCID: PMC5972459 DOI: 10.1152/japplphysiol.00563.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 11/06/2017] [Accepted: 12/12/2017] [Indexed: 12/16/2022] Open
Abstract
Aging muscle atrophy is in part a neurodegenerative process revealed by denervation/reinnervation events leading to motor unit remodeling (i.e., myofiber type grouping). However, this process and its physiological relevance are poorly understood, as is the wide-ranging heterogeneity among aging humans. Here, we attempted to address 1) the relation between myofiber type grouping and molecular regulators of neuromuscular junction (NMJ) stability; 2) the impact of motor unit remodeling on recruitment during submaximal contractions; 3) the prevalence and impact of motor unit remodeling in Parkinson's disease (PD), an age-related neurodegenerative disease; and 4) the influence of resistance exercise training (RT) on regulators of motor unit remodeling. We compared type I myofiber grouping, molecular regulators of NMJ stability, and the relative motor unit activation (MUA) requirement during a submaximal sit-to-stand task among untrained but otherwise healthy young (YA; 26 yr, n = 27) and older (OA; 66 yr, n = 91) adults and OA with PD (PD; 67 yr, n = 19). We tested the effects of RT on these outcomes in OA and PD. PD displayed more motor unit remodeling, alterations in NMJ stability regulation, and a higher relative MUA requirement than OA, suggesting PD-specific effects. The molecular and physiological outcomes tracked with the severity of type I myofiber grouping. Together these findings suggest that age-related motor unit remodeling, manifested by type I myofiber grouping, 1) reduces MUA efficiency to meet submaximal contraction demand, 2) is associated with disruptions in NMJ stability, 3) is further impacted by PD, and 4) may be improved by RT in severe cases. NEW & NOTEWORTHY Because the physiological consequences of varying amounts of myofiber type grouping are unknown, the current study aims to characterize the molecular and physiological correlates of motor unit remodeling. Furthermore, because exercise training has demonstrated neuromuscular benefits in aged humans and improved innervation status and neuromuscular junction integrity in animals, we provide an exploratory analysis of the effects of high-intensity resistance training on markers of neuromuscular degeneration in both Parkinson's disease (PD) and age-matched older adults.
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Affiliation(s)
- Neil A Kelly
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham , Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Kelley G Hammond
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham , Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - C Scott Bickel
- Department of Physical Therapy, University of Alabama at Birmingham , Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Samuel T Windham
- Department of Surgery, University of Alabama at Birmingham , Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - S Craig Tuggle
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham , Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Marcas M Bamman
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham , Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
- Geriatric Research, Education, and Clinical Center, Birmingham Veterans Affairs Medical Center , Birmingham, Alabama
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103
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Piasecki M, Ireland A, Piasecki J, Stashuk DW, Swiecicka A, Rutter MK, Jones DA, McPhee JS. Failure to expand the motor unit size to compensate for declining motor unit numbers distinguishes sarcopenic from non-sarcopenic older men. J Physiol 2018. [PMID: 29527694 PMCID: PMC5924831 DOI: 10.1113/jp275520] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Key points The age‐related loss of muscle mass is related to the loss of innervating motor neurons and denervation of muscle fibres. Not all denervated muscle fibres are degraded; some may be reinnervated by an adjacent surviving neuron, which expands the innervating motor unit proportional to the numbers of fibres rescued. Enlarged motor units have larger motor unit potentials when measured using electrophysiological techniques. We recorded much larger motor unit potentials in relatively healthy older men compared to young men, but the older men with the smallest muscles (sarcopenia) had smaller motor unit potentials than healthy older men. These findings suggest that healthy older men reinnervate large numbers of muscle fibres to compensate for declining motor neuron numbers, but a failure to do so contributes to muscle loss in sarcopenic men.
Abstract Sarcopenia results from the progressive loss of skeletal muscle mass and reduced function in older age. It is likely to be associated with the well‐documented reduction of motor unit numbers innervating limb muscles and the increase in size of surviving motor units via reinnervation of denervated fibres. However, no evidence exists to confirm the extent of motor unit remodelling in sarcopenic individuals. The aim of the present study was to compare motor unit size and number between young (n = 48), non‐sarcopenic old (n = 13), pre‐sarcopenic (n = 53) and sarcopenic (n = 29) men. Motor unit potentials (MUPs) were isolated from intramuscular and surface EMG recordings. The motor unit numbers were reduced in all groups of old compared with young men (all P < 0.001). MUPs were higher in non‐sarcopenic and pre‐sarcopenic men compared with young men (P = 0.039 and 0.001 respectively), but not in the vastus lateralis of sarcopenic old (P = 0.485). The results suggest that extensive motor unit remodelling occurs relatively early during ageing, exceeds the loss of muscle mass and precedes sarcopenia. Reinnervation of denervated muscle fibres probably expands the motor unit size in the non‐sarcopenic and pre‐sarcopenic old, but not in the sarcopenic old. These findings suggest that a failure to expand the motor unit size distinguishes sarcopenic from pre‐sarcopenic muscles. The age‐related loss of muscle mass is related to the loss of innervating motor neurons and denervation of muscle fibres. Not all denervated muscle fibres are degraded; some may be reinnervated by an adjacent surviving neuron, which expands the innervating motor unit proportional to the numbers of fibres rescued. Enlarged motor units have larger motor unit potentials when measured using electrophysiological techniques. We recorded much larger motor unit potentials in relatively healthy older men compared to young men, but the older men with the smallest muscles (sarcopenia) had smaller motor unit potentials than healthy older men. These findings suggest that healthy older men reinnervate large numbers of muscle fibres to compensate for declining motor neuron numbers, but a failure to do so contributes to muscle loss in sarcopenic men.
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Affiliation(s)
- M Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - A Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - J Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - D W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Ontario, N2L 3G1, Canada
| | - A Swiecicka
- Andrology Research Unit, Cardiovascular, Metabolic and Nutritional Sciences Domain, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - M K Rutter
- Andrology Research Unit, Cardiovascular, Metabolic and Nutritional Sciences Domain, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.,Manchester Diabetes Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - D A Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - J S McPhee
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
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104
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Hendrickse P, Galinska M, Hodson-Tole E, Degens H. An evaluation of common markers of muscle denervation in denervated young-adult and old rat gastrocnemius muscle. Exp Gerontol 2018. [PMID: 29524469 DOI: 10.1016/j.exger.2018.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A large part of age-related muscle wasting is due to incomplete reinnervation of fibres that have become denervated following motoneuron loss. Neural cell adhesion molecule (NCAM) and sodium channel NaV1.5 are considered markers for denervation, but the time course of changes in their expression following denervation has never been systematically evaluated in young-adult and old muscle. To assess the time course of denervation-induced changes in their expression, the left gastrocnemius muscle in 15 young-adult (5-month) and 10 old (25-month) male Wistar rats was denervated for 1, 2 or 4 weeks, while the right muscle served as an internal control. Sections were stained for α-bungarotoxin, to visualise the neuromuscular junctions, combined with NCAM, polysialylated NCAM (PSA-NCAM) or NaV1.5. In young-adult animals, denervation induced a transient decrease in junctional and cytoplasmic NCAM expression, while in the old NCAM expression was increased after 2 weeks. Cytoplasmic PSA-NCAM was increased in both young-adult and old fibres after 2 weeks denervation with a further increase after 4 weeks in the young only. The junctional PSA-NCAM was transiently increased or decreased in the young and old muscles, respectively. NaV1.5 expression decreased after 1 and 2 weeks of denervation in NaV1.5 in young muscle fibres before returning to control levels, whereas old muscle fibres displayed a transient increase after 1 week followed by a decrease and a return to control levels after 2 and 4 weeks respectively. In conclusion, NCAM and NaV1.5 are not unequivocally elevated with denervation and consequently are not adequate markers of fibre denervation.
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Affiliation(s)
- Paul Hendrickse
- School of Healthcare Science, Manchester Metropolitan University, UK; Institute of Sport Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania.
| | | | - Emma Hodson-Tole
- School of Healthcare Science, Manchester Metropolitan University, UK
| | - Hans Degens
- School of Healthcare Science, Manchester Metropolitan University, UK; Institute of Sport Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania.
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105
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Santana A, Debastiani JC, Kunz RI, Buratti P, Brancalhão RMC, de Fátima Chasko Ribeiro L, Torrejais MM, Bertolini GRF. Association of sericin and swimming on the phenotype, motor plate, and functionality of the denervated plantar muscle of Wistar rats. J Exerc Rehabil 2018; 14:24-31. [PMID: 29511649 PMCID: PMC5833964 DOI: 10.12965/jer.1835138.569] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/23/2018] [Indexed: 01/24/2023] Open
Abstract
Physical exercise may help maintain muscle properties and functional improvement after peripheral nerve lesion, which may be enhanced by using biocompatible substances, such as sericin. The aim of this study was analyse the effect of sericin associated with swimming exercise on the phenotype, innervation, and functionality of the plantar muscle of Wistar rats. Forty randomly divided adult rats were used in five groups of eight animals: control, injury, sericin, exercise, exercise and sericin. The application of sericin was done on the spot, 100 μL, shortly after nerve compression. Three days after sciatic nerve compression, the swimming and swimming and sericin groups were submitted to physical swimming exercise for 21 days. Afterwards, the animals were euthanised and the plantar muscle was dissected and submitted to histochemical and histoenzymological techniques. The grip strength test did not show alterations in muscular functionality, and the control presented greater muscle mass in relation to the other groups, the same did not occur for muscle length. Polymorphic neuromuscular junctions were detected in the groups, although without significant morphometric alterations of the area, major and minor diameters. The percentage of type I fibres was lower in the lesion group and there was no difference in fibres IIa and IIb between groups. The area of fibres I, IIa and IIb remained constant between groups. Sericin biopolymer combined with swimming exercise did not affect plantar muscle function, submitted to experimental axonotmosis, whose contractile properties were altered by nerve injury.
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Affiliation(s)
- André Santana
- Programa de Pós-Graduação em Biociências e Saúde da, Universidade Estadual do Oeste do Paraná (UNIOESTE), Cascavel, Brazil
| | - Jean Carlos Debastiani
- Programa de Pós-Graduação em Biociências e Saúde da, Universidade Estadual do Oeste do Paraná (UNIOESTE), Cascavel, Brazil
| | - Regina Inês Kunz
- Universidade Estadual do Oeste do Paraná (UNIOESTE), Cascavel, Brazil
| | - Pamela Buratti
- Programa de Pós-Graduação em Biociências e Saúde da, Universidade Estadual do Oeste do Paraná (UNIOESTE), Cascavel, Brazil
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106
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Kougias DG, Das T, Perez AB, Pereira SL. A role for nutritional intervention in addressing the aging neuromuscular junction. Nutr Res 2018; 53:1-14. [PMID: 29804584 DOI: 10.1016/j.nutres.2018.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 02/14/2018] [Accepted: 02/14/2018] [Indexed: 12/20/2022]
Abstract
The purpose of this review is to discuss the structural and physiological changes that underlie age-related neuromuscular dysfunction and to summarize current evidence on the potential role of nutritional interventions on neuromuscular dysfunction-associated pathways. Age-related neuromuscular deficits are known to coincide with distinct changes in the central and peripheral nervous system, in the neuromuscular system, and systemically. Although many features contribute to the age-related decline in neuromuscular function, a comprehensive understanding of their integration and temporal relationship is needed. Nonetheless, many nutrients and ingredients show promise in modulating neuromuscular output by counteracting the age-related changes that coincide with neuromuscular dysfunction. In particular, dietary supplements, such as vitamin D, omega-3 fatty acids, β-hydroxy-β-methylbutyrate, creatine, and dietary phospholipids, demonstrate potential in ameliorating age-related neuromuscular dysfunction. However, current evidence seldom directly assesses neuromuscular outcomes and is not always in the context of aging. Additional clinical research studies are needed to confirm the benefits of dietary supplements on neuromuscular function, as well as to define the appropriate population, dosage, and duration for intervention.
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Affiliation(s)
- Daniel G Kougias
- Abbott Nutrition, Strategic Research, 3300 Stelzer Road, Columbus, OH, USA; Neuroscience Program, University of Illinois, Urbana-Champaign, IL, USA.
| | - Tapas Das
- Abbott Nutrition, Strategic Research, 3300 Stelzer Road, Columbus, OH, USA.
| | | | - Suzette L Pereira
- Abbott Nutrition, Strategic Research, 3300 Stelzer Road, Columbus, OH, USA.
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107
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Nielsen KB, Lal NN, Sheard PW. Age-related remodelling of the myotendinous junction in the mouse soleus muscle. Exp Gerontol 2018; 104:52-59. [PMID: 29421351 DOI: 10.1016/j.exger.2018.01.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/18/2017] [Accepted: 01/18/2018] [Indexed: 11/19/2022]
Abstract
The age-related loss of muscle mass and function predominantly affect muscles of the lower limbs and have largely been associated with decline in muscle fibre size and number, although the exact mechanisms underlying these losses are poorly understood. In addition, consistent reports that the loss of muscle strength exceeds that which can be explained by declines in muscle mass has widened the search for causes of sarcopenia to include supporting tissues such as the extracellular matrix and tendons. Although the changes to both muscle and tendon with age are well characterised, little work has focused on the interface between these two tissues, the myotendinous junction (MTJ). Given the crucial role for this structure in force transfer between muscle and tendon, we asked whether the myotendinous junction underwent structural changes with age in lower limb muscle. We used whole muscle to assess gross muscle and tendon morphology, and immunohistochemistry to determine fibre and MTJ profile number in young (6 months), middle aged (18 months) and elderly (24 months) C57BL/6 female mice. MTJ length was quantified using serial cross sections of the soleus muscle. We found an apparent 3.5-fold increase in MTJ profiles per cross section with no increase in fibre number in old mice, and found this to be a result of a doubling in length of the MTJ region with age. This coincided with an increase in proximal tendon length (31%), as well as an increase in collagen deposition between 6 and 24-months of age consistent with an expansion of the fibre termination area. These findings uncover a previously undescribed effect of ageing on the MTJ and open up new lines of investigation into the role of this structure in the age-related loss of muscle function.
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Affiliation(s)
| | - Navneet N Lal
- Department of Physiology, University of Otago, New Zealand
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108
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Siddiqi A, Poosapadi Arjunan S, Kumar DK. Computational model to investigate the relative contributions of different neuromuscular properties of tibialis anterior on force generated during ankle dorsiflexion. Med Biol Eng Comput 2018; 56:1413-1423. [PMID: 29335929 DOI: 10.1007/s11517-018-1788-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 01/06/2018] [Indexed: 10/18/2022]
Abstract
This study describes a new model of the force generated by tibialis anterior muscle with three new features: single-fiber action potential, twitch force, and pennation angle. This model was used to investigate the relative effects and interaction of ten age-associated neuromuscular parameters. Regression analysis (significance level of 0.05) between the neuromuscular properties and corresponding simulated force produced at the footplate was performed. Standardized slope coefficients were computed to rank the effect of the parameters. The results show that reduction in the average firing rate is the reason for the sharp decline in the force and other factors, such as number of muscle fibers, specific force, pennation angle, and innervation ratio. The fast fiber ratio affects the simulated force through two significant interactions. This study has ranked the individual contributions of the neuromuscular factors to muscle strength decline of the TA and identified firing rate decline as the biggest cause followed by decrease in muscle fiber number and specific force. The strategy for strength preservation for the elderly should focus on improving firing rate. Graphical abstract Neuromuscular properties of Tibialis Anterior on force generated during ankle dorsiflexion.
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Affiliation(s)
- Ariba Siddiqi
- Biosignals Laboratory, School of Engineering, RMIT University, GPO Box 2476, Melbourne, VIC, Australia
| | - Sridhar Poosapadi Arjunan
- Biosignals Laboratory, School of Engineering, RMIT University, GPO Box 2476, Melbourne, VIC, Australia.
| | - Dinesh Kant Kumar
- Biosignals Laboratory, School of Engineering, RMIT University, GPO Box 2476, Melbourne, VIC, Australia
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109
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Zhou J, Liao Z, Chen J, Zhao K, Xiao Q. Integrated study on comparative transcriptome and skeletal muscle function in aged rats. Mech Ageing Dev 2018; 169:32-39. [PMID: 29325930 DOI: 10.1016/j.mad.2018.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 12/20/2017] [Accepted: 01/06/2018] [Indexed: 01/05/2023]
Abstract
The present study aimed to reveal aging-related changes in the skeletal muscle of SD rats by comparing transcriptome analysis, integrated with muscle physiological parameters. Ten rats aged 25 months were set as the old group (OG) and ten rats aged 6 months were set as the young group (YG). After 6 weeks of feeding, the body mass, grip strength, and gastrocnemius muscle mass were determined, and the differentially expressed genes were analyzed by transcriptome sequencing, followed by GO enrichment analysis and KEGG analysis. The results showed that the muscle index and the relative grip strength were lower in OG rats than YG rats. The expressions of AMPK, UCP3, IGF-1, several ion channel associated genes and collagen family genes were down-regulated in OG rats. MGMT, one of the strength determining genes and CHRNa1, a subunit of the acetylcholine receptor were up-regulated in OG rats. The present results supply the global transcriptomic information involved in aging related skeletal muscle dysfunction in rats. The reduced expressions of AMPK, IGF-1, and CASK can explain the losses of muscle mass and function in the aged rats. In addition, the up-regulation of MGMT and CHRNa1 also contribute to muscle wasting and weakness during aging.
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Affiliation(s)
- Jing Zhou
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016, Chongqing, China
| | - Zhiyin Liao
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016, Chongqing, China
| | - Jinliang Chen
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016, Chongqing, China
| | - Kexiang Zhao
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016, Chongqing, China
| | - Qian Xiao
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016, Chongqing, China.
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110
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Ábrigo J, Elorza AA, Riedel CA, Vilos C, Simon F, Cabrera D, Estrada L, Cabello-Verrugio C. Role of Oxidative Stress as Key Regulator of Muscle Wasting during Cachexia. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:2063179. [PMID: 29785242 PMCID: PMC5896211 DOI: 10.1155/2018/2063179] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 02/07/2018] [Indexed: 12/11/2022]
Abstract
Skeletal muscle atrophy is a pathological condition mainly characterized by a loss of muscular mass and the contractile capacity of the skeletal muscle as a consequence of muscular weakness and decreased force generation. Cachexia is defined as a pathological condition secondary to illness characterized by the progressive loss of muscle mass with or without loss of fat mass and with concomitant diminution of muscle strength. The molecular mechanisms involved in cachexia include oxidative stress, protein synthesis/degradation imbalance, autophagy deregulation, increased myonuclear apoptosis, and mitochondrial dysfunction. Oxidative stress is one of the most common mechanisms of cachexia caused by different factors. It results in increased ROS levels, increased oxidation-dependent protein modification, and decreased antioxidant system functions. In this review, we will describe the importance of oxidative stress in skeletal muscles, its sources, and how it can regulate protein synthesis/degradation imbalance, autophagy deregulation, increased myonuclear apoptosis, and mitochondrial dysfunction involved in cachexia.
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Affiliation(s)
- Johanna Ábrigo
- 1Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
- 2Millennium Institute of Immunology and Immunotherapy, Santiago, Chile
| | - Alvaro A. Elorza
- 2Millennium Institute of Immunology and Immunotherapy, Santiago, Chile
- 3Centro de Investigaciones Biomédicas, Facultad de Ciencias Biológicas & Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
| | - Claudia A. Riedel
- 1Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
- 2Millennium Institute of Immunology and Immunotherapy, Santiago, Chile
| | - Cristian Vilos
- 4Laboratory of Nanomedicine and Targeted Delivery, Center for Integrative Medicine and Innovative Science, Faculty of Medicine, and Center for Bioinformatics and Integrative Biology, Faculty of Biological Sciences, Universidad Andres Bello, Santiago, Chile
- 5Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago, Chile
| | - Felipe Simon
- 1Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
- 2Millennium Institute of Immunology and Immunotherapy, Santiago, Chile
| | - Daniel Cabrera
- 6Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- 7Departamento de Ciencias Químicas y Biológicas, Facultad de Salud, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Lisbell Estrada
- 8Centro Integrativo de Biología y Química Aplicada, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Claudio Cabello-Verrugio
- 1Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
- 2Millennium Institute of Immunology and Immunotherapy, Santiago, Chile
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111
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Friedrich O, Diermeier S, Larsson L. Weak by the machines: muscle motor protein dysfunction - a side effect of intensive care unit treatment. Acta Physiol (Oxf) 2018; 222. [PMID: 28387014 DOI: 10.1111/apha.12885] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/12/2017] [Accepted: 04/04/2017] [Indexed: 12/25/2022]
Abstract
Intensive care interventions involve periods of mechanical ventilation, sedation and complete mechanical silencing of patients. Critical illness myopathy (CIM) is an ICU-acquired myopathy that is associated with limb muscle weakness, muscle atrophy, electrical silencing of muscle and motor proteinopathy. The hallmark of CIM is a preferential muscle myosin loss due to increased catabolic and reduced anabolic activity. The ubiquitin proteasome pathway plays an important role, apart from recently identified novel mechanisms affecting non-lysosomal protein degradation or autophagy. CIM is not reproduced by pure disuse atrophy, denervation atrophy, steroid-induced atrophy or septic myopathy, although combinations of high-dose steroids and denervation can mimic CIM. New animal models of critical illness and ICU treatment (i.e. mechanical ventilation and complete immobilization) provide novel insights regarding the time course of protein synthesis and degradation alterations, and the role of protective chaperone activities in the process of myosin loss. Altered mechano-signalling seems involved in triggering a major part of myosin loss in experimental CIM models, and passive loading of muscle potently ameliorates the CIM phenotype. We provide a systematic overview of similarities and distinct differences in the signalling pathways involved in triggering muscle atrophy in CIM and isolated trigger factors. As preferential myosin loss is mostly determined from biochemistry analyses providing no spatial resolution of myosin loss processes within myofibres, we also provide first results monitoring myosin signal intensities during experimental ICU intervention using multi-photon Second Harmonic Generation microscopy. Our results confirm that myosin loss is an evenly distributed process within myofibres rather than being confined to hot spots.
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Affiliation(s)
- O. Friedrich
- Institute of Medical Biotechnology; Friedrich-Alexander-University Erlangen-Nürnberg; Erlangen Germany
- Erlangen Graduate School in Advanced Optical Technologie (SAOT); Friedrich-Alexander-University Erlangen-Nürnberg; Erlangen Germany
| | - S. Diermeier
- Institute of Medical Biotechnology; Friedrich-Alexander-University Erlangen-Nürnberg; Erlangen Germany
- Erlangen Graduate School in Advanced Optical Technologie (SAOT); Friedrich-Alexander-University Erlangen-Nürnberg; Erlangen Germany
| | - L. Larsson
- Department of Physiology & Pharmacology; Karolinska Institutet; Stockholm Sweden
- Section of Clinical Neurophysiology; Department of Clinical Neuroscience; Karolinska Institutet; Stockholm Sweden
- Department of Biobehavioral Health; The Pennsylvania State University; University Park PA USA
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112
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Liu W, Chakkalakal JV. The Composition, Development, and Regeneration of Neuromuscular Junctions. Curr Top Dev Biol 2018; 126:99-124. [DOI: 10.1016/bs.ctdb.2017.08.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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113
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Wu G, Xu S, Chen B, Wu P. Relationship between changes in muscle fibers and CMAP in skeletal muscle with different stages of aging. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2017; 10:11888-11895. [PMID: 31966553 PMCID: PMC6966042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 11/21/2017] [Indexed: 06/10/2023]
Abstract
AIM This study aimed to investigate the relationship between the changes of muscle fibers and the changesof peripheral nerve functions (CMAP) with aging. METHODS Lewis rats enrolled in this study. Muscle biopsy and CMAP of tibialis anterior (TA) were measured. RESULTS CMAP amplitudes increased significantly in 6 months (P<0.05). CMAP latencies of peroneal nerves found to be significantly higher in older rats (P<0.05). In 6 months these two muscle fibers went through a significant decrease (P<0.05). Type IIb and type IIx muscle fibers increased significantly in 6 months when compared with those in 1 month (P<0.05). After 6 months, the percentages of type I and type IIa muscle fibers increased as the month increased (P<0.05). The percentages of type IIb muscle fibers and type IIx muscle fibers dropped significantly as the month increased (P<0.05). Type I and type IIa muscle fibers were negatively related to CMAP amplitudes (P<0.05). Type IIb muscle fibers were positively related to CMAP amplitudes (P<0.05). CONCLUSION AND DISCUSSION There is a shift from the fast types (Type IIx and IIb) to slow types (Type I and IIa) in muscle fibers with agingwhich is consistent with changes in CMAP amplitude of peripheral nerves.
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Affiliation(s)
- Genbin Wu
- Department of Orthopedics, Shanghai Tenth People’s Hospital Affiliated to Tongji UniversityShanghai, China
| | - Sudan Xu
- Department of Cardiology, Shanghai First People’s Hospital Affiliated to Shanghai Jiao Tong UniversityShanghai, China
| | - Biao Chen
- Department of Orthopedics, Shanghai Tenth People’s Hospital Affiliated to Tongji UniversityShanghai, China
| | - Peng Wu
- Department of Orthopedics, Shanghai Tenth People’s Hospital Affiliated to Tongji UniversityShanghai, China
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114
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Vorobej K, Mitchell AS, Smith IC, Donath S, Russell Tupling A, Quadrilatero J. The effect of ARC ablation on skeletal muscle morphology, function, and apoptotic signaling during aging. Exp Gerontol 2017; 101:69-79. [PMID: 29056555 DOI: 10.1016/j.exger.2017.10.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/11/2017] [Accepted: 10/18/2017] [Indexed: 12/24/2022]
Abstract
Augmented apoptotic signaling can result in degradation of skeletal muscle proteins and loss of myonuclei, ultimately contributing to muscle atrophy and contractile dysfunction. Apoptosis repressor with caspase recruitment domain (ARC) is an anti-apoptotic protein highly expressed in skeletal muscle. Here we examined the role of ARC on age-related skeletal muscle apoptosis and wasting by utilizing an ARC-deficient mouse model. Aged mice displayed a number of morphological, phenotypic, and contractile alterations in both soleus and plantaris muscle with aging. Although no differences were found in proteolytic enzyme activity, ARC protein decreased while several anti-apoptotic proteins (e.g., BCL2, BCLXL, HSP70, and XIAP) and the release of mitochondrial housed protein (i.e., SMAC, AIF) increased in aged muscle. Importantly, ARC KO mice had low muscle weights and fewer fibers in soleus, with 2-year-old ARC KO mice displaying lower mitochondrial BCL2 protein along with augmented release of CYTC and SMAC in red/oxidative muscle. Overall, these results indicate that aged skeletal muscle undergoes atrophy as well as contractile and fiber type composition alterations despite an increase in anti-apoptotic protein expression. Although some mitochondrial-specific apoptotic alterations occurred in skeletal muscle due to ARC ablation over the lifespan, our data suggest that ARC may not have a large influence during skeletal muscle aging.
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Affiliation(s)
- Kira Vorobej
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Andrew S Mitchell
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Ian C Smith
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Stefan Donath
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany; Center for Stroke Research Berlin, Charite-University Medicine, Berlin, Germany; Department of Cardiology and Nephrology, HELIOS Clinics GmbH, Berlin, Germany
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
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115
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Burd NA, De Lisio M. Skeletal Muscle Remodeling: Interconnections Between Stem Cells and Protein Turnover. Exerc Sport Sci Rev 2017; 45:187-191. [PMID: 28419002 DOI: 10.1249/jes.0000000000000117] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nutrition and exercise are important components of a healthy lifestyle to improve rates of hypertrophic and nonhypertrophic skeletal muscle remodeling. We provide evidence to support the hypothesis that muscle stem cells and protein turnover are collaborative, not separate, mechanisms supporting muscle remodeling by facilitating protein, nuclear, and cellular turnover in response to the ingestion of protein dense foods and exercise.
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Affiliation(s)
- Nicholas A Burd
- 1Department of Kinesiology and Community Health, Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, IL; and 2School of Human Kinetics, Brain and Mind Institute, Centre for Neuromuscular Disease, and Regenerative Medicine Program, University of Ottawa, Ottawa, ON, Canada
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116
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Cappello V, Francolini M. Neuromuscular Junction Dismantling in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2017; 18:ijms18102092. [PMID: 28972545 PMCID: PMC5666774 DOI: 10.3390/ijms18102092] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/25/2017] [Accepted: 09/28/2017] [Indexed: 12/13/2022] Open
Abstract
Neuromuscular junction assembly and plasticity during embryonic, postnatal, and adult life are tightly regulated by the continuous cross-talk among motor nerve endings, muscle fibers, and glial cells. Altered communications among these components is thought to be responsible for the physiological age-related changes at this synapse and possibly for its destruction in pathological states. Neuromuscular junction dismantling plays a crucial role in the onset of Amyotrophic Lateral Sclerosis (ALS). ALS is characterized by the degeneration and death of motor neurons leading to skeletal muscle denervation, atrophy and, most often, death of the patient within five years from diagnosis. ALS is a non-cell autonomous disease as, besides motor neuron degeneration, glial cells, and possibly muscle fibers, play a role in its onset and progression. Here, we will review the recent literature regarding the mechanisms leading to neuromuscular junction disassembly and muscle denervation focusing on the role of the three players of this peripheral tripartite synapse.
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Affiliation(s)
- Valentina Cappello
- Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12, 56127 Pisa, Italy.
| | - Maura Francolini
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano-Via Vanvitelli 32, 20129 Milano, Italy.
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117
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Gagliano-Jucá T, Storer TW, Pencina KM, Travison TG, Li Z, Huang G, Hettwer S, Dahinden P, Bhasin S, Basaria S. Testosterone does not affect agrin cleavage in mobility-limited older men despite improvement in physical function. Andrology 2017; 6:29-36. [DOI: 10.1111/andr.12424] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 06/29/2017] [Accepted: 08/03/2017] [Indexed: 12/27/2022]
Affiliation(s)
- T. Gagliano-Jucá
- Research Program in Men's Health: Aging and Metabolism; Brigham and Women's Hospital; Harvard Medical School; Boston MA USA
| | - T. W. Storer
- Research Program in Men's Health: Aging and Metabolism; Brigham and Women's Hospital; Harvard Medical School; Boston MA USA
| | - K. M. Pencina
- Research Program in Men's Health: Aging and Metabolism; Brigham and Women's Hospital; Harvard Medical School; Boston MA USA
| | | | - Z. Li
- Research Program in Men's Health: Aging and Metabolism; Brigham and Women's Hospital; Harvard Medical School; Boston MA USA
| | - G. Huang
- Research Program in Men's Health: Aging and Metabolism; Brigham and Women's Hospital; Harvard Medical School; Boston MA USA
| | | | | | - S. Bhasin
- Research Program in Men's Health: Aging and Metabolism; Brigham and Women's Hospital; Harvard Medical School; Boston MA USA
| | - S. Basaria
- Research Program in Men's Health: Aging and Metabolism; Brigham and Women's Hospital; Harvard Medical School; Boston MA USA
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118
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Moore CW, Beveridge TS, Rice CL. Fiber type composition of the palmaris brevis muscle: implications for palmar function. J Anat 2017. [PMID: 28620932 DOI: 10.1111/joa.12652] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The palmaris brevis (PB) is a small muscle of variant morphology located on the ulnar aspect of the palm, superficial to the hypothenar eminence. Functionally, the PB has been proposed to protect the neurovasculature of the ulnar canal from compressive forces during repetitive or intermittent trauma associated with grasping. Although PB function has been inferred from cadaveric observations, it is unknown whether it has the contractile capacity and fatigue-resistance necessary to withstand these functional demands. Insight into the functional specialization of the PB can be provided through investigating the proportions of type I and type II muscle fibers by staining for myosin heavy chain (MHC) isoforms using immunohistochemical methods. Therefore, the purpose of this study was to quantify the proportion of type I and type II muscle fibers to provide insight into the role of the PB in palmar function based on its gross histological structure. Sixteen PB specimens were harvested from the hands (eight right, eight left) of eight formalin-embalmed cadavers (mean age: 75 ± 14 years; three males, five females). PB muscle composition was determined by labeling serial cross-sections with MHC type I and type II monoclonal antibodies. The results indicate that the PB is primarily composed of type I muscle fibers (72.2 ± 13.7%), with no significant differences between left and right hands. Given the predominance of type I muscle fibers, our findings indicate the PB may be fatigue-resistant and thus, capable of contracting for prolonged durations. This supports cadaveric observations indicating that the PB functions to protect the ulnar neurovasculature of the palm by providing a muscular barrier in addition to serving as a functional anchor to the hypothenar fat pad when objects are firmly compressed into the palm.
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Affiliation(s)
- Colin W Moore
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, ON, Canada
| | - Tyler S Beveridge
- Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, ON, Canada.,Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
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119
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Ketogenic diet induces expression of the muscle circadian gene Slc25a25 via neural pathway that might be involved in muscle thermogenesis. Sci Rep 2017; 7:2885. [PMID: 28588221 PMCID: PMC5460244 DOI: 10.1038/s41598-017-03119-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/24/2017] [Indexed: 12/14/2022] Open
Abstract
We recently found that the mRNA expression of Slc25a25, a Ca2+-sensitive ATP carrier in the inner mitochondrial membrane, fluctuates in a circadian manner in mouse skeletal muscle. We showed here that the circadian expression of muscle Slc25a25 was damped in Clock mutant, muscle-specific Bmal1-deficient, and global Bmal1-deficient mice. Furthermore, a ketogenic diet (KD) that induces time-of-day-dependent hypothermia (torpor), induced Slc25a25 mRNA expression in skeletal muscle. Hypothermia induced by KD did not affect thermogenic genes such as Sarcolipin and Pgc1a in muscles and Ucp1 in adipose tissues. Sciatic denervation abolished circadian and KD-induced Slc25a25 expression, suggesting that the circadian clock regulates muscle Slc25a25 expression via neural pathways. We measured body temperature (Tb) in sciatic denervated mice fed with KD to determine the functional role of KD-induced Slc25a25 expression. Sciatic denervation abolished Slc25a25 expression and augmented KD-induced hypothermia compared with sham-operated mice, but did not affect Tb in mice given a normal diet. These findings suggest that KD feeding induces expression of the muscle circadian gene Slc25a25 via neural pathways, and that SLC25A25 might be involved in muscle thermogenesis under KD-induced hypothermia in mammals.
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120
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Chung T, Park JS, Kim S, Montes N, Walston J, Höke A. Evidence for dying-back axonal degeneration in age-associated skeletal muscle decline. Muscle Nerve 2017; 55:894-901. [PMID: 27464347 DOI: 10.1002/mus.25267] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 07/21/2016] [Accepted: 07/26/2016] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Age-associated muscle strength decline is a major contributing factor to increased late-life functional decline and comorbidity, and is strongly associated with early mortality. Although all parts of the neuromuscular system seem to be affected by aging, dying-back of motor axons likely plays a major role. METHODS We compared the degeneration in ventral roots and neuromuscular junction denervation in young and aged mice and correlated the findings with strength and electrophysiological measures. RESULTS With normal aging, there is little decline in motor axon numbers in the ventral roots, but the neuromuscular junctions show marked partial denervation that is associated with increased jitter on stimulated single fiber electromyography and a decrease in muscle strength. CONCLUSIONS These findings suggest that dying-back axonal degeneration may be partially responsible for the electrophysiological and strength changes observed with aging. Muscle Nerve 55: 894-901, 2017.
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Affiliation(s)
- Tae Chung
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Jae Sung Park
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, 21205, USA.,Department of Physical Education, Kongju National University, Gongju, Republic of Korea
| | - Sangri Kim
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, 21205, USA
| | - Nataly Montes
- Department of Physical Medicine and Rehabilitation, VA Caribbean Healthcare System, San Juan, Puerto Rico
| | - Jeremy Walston
- Department of Medicine, Johns Hopkins, Baltimore, Maryland, USA
| | - Ahmet Höke
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, 21205, USA
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121
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Baehr LM, West DWD, Marshall AG, Marcotte GR, Baar K, Bodine SC. Muscle-specific and age-related changes in protein synthesis and protein degradation in response to hindlimb unloading in rats. J Appl Physiol (1985) 2017; 122:1336-1350. [PMID: 28336537 DOI: 10.1152/japplphysiol.00703.2016] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 02/16/2017] [Accepted: 02/26/2017] [Indexed: 12/19/2022] Open
Abstract
Disuse is a potent inducer of muscle atrophy, but the molecular mechanisms driving this loss of muscle mass are highly debated. In particular, the extent to which disuse triggers decreases in protein synthesis or increases in protein degradation, and whether these changes are uniform across muscles or influenced by age, is unclear. We aimed to determine the impact of disuse on protein synthesis and protein degradation in lower limb muscles of varied function and fiber type in adult and old rats. Alterations in protein synthesis and degradation were measured in the soleus, medial gastrocnemius, and tibialis anterior (TA) muscles of adult and old rats subjected to hindlimb unloading (HU) for 3, 7, or 14 days. Loss of muscle mass was progressive during the unloading period, but highly variable (-9 to -38%) across muscle types and between ages. Protein synthesis decreased significantly in all muscles, except for the old TA. Atrophy-associated gene expression was only loosely associated with protein degradation as muscle RING finger-1, muscle atrophy F-box (MAFbx), and Forkhead box O1 expression significantly increased in all muscles, but an increase in proteasome activity was only observed in the adult soleus. MAFbx protein levels were significantly higher in the old muscles compared with adult muscles, despite the old having higher expression of microRNA-23a. These results indicate that adult and old muscles respond similarly to HU, and the greatest loss in muscle mass occurs in predominantly slow-twitch extensor muscles due to a concomitant decrease in protein synthesis and increase in protein degradation.NEW & NOTEWORTHY In this study, we showed that age did not intensify the atrophy response to unloading in rats, but rather that the degree of atrophy was highly variable across muscles, indicating that changes in protein synthesis and protein degradation occur in a muscle-specific manner. Our data emphasize the importance of studying muscles of varying fiber-type and physiological function at multiple time points to fully understand the molecular mechanisms responsible for disuse atrophy.
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Affiliation(s)
- Leslie M Baehr
- Veterans Affairs Northern California Health Care System, Mather, California.,Department of Physiology and Membrane Biology, University of California Davis, Davis, California; and
| | - Daniel W D West
- Veterans Affairs Northern California Health Care System, Mather, California.,Department of Physiology and Membrane Biology, University of California Davis, Davis, California; and
| | - Andrea G Marshall
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California; and
| | - George R Marcotte
- Veterans Affairs Northern California Health Care System, Mather, California
| | - Keith Baar
- Veterans Affairs Northern California Health Care System, Mather, California.,Department of Physiology and Membrane Biology, University of California Davis, Davis, California; and.,Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
| | - Sue C Bodine
- Veterans Affairs Northern California Health Care System, Mather, California; .,Department of Physiology and Membrane Biology, University of California Davis, Davis, California; and.,Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
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122
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Ding Y, Li J, Liu Z, Liu H, Li H, Li Z. IGF-1 potentiates sensory innervation signalling by modulating the mitochondrial fission/fusion balance. Sci Rep 2017; 7:43949. [PMID: 28276453 PMCID: PMC5343424 DOI: 10.1038/srep43949] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/31/2017] [Indexed: 01/07/2023] Open
Abstract
Restoring the contractile function of long-term denervated skeletal muscle (SKM) cells is difficult due to the long period of denervation, which causes a loss of contractility. Although sensory innervation is considered a promising protective approach, its effect is still restricted. In this study, we introduced insulin-like growth factor-1 (IGF-1) as an efficient protective agent and observed that IGF-1 potentiated the effects of sensory protection by preventing denervated muscle atrophy and improving the condition of denervated muscle cells in vivo and in vitro. IGF-1-induced Akt phosphorylation suppressed the mitochondrial outer-membrane protein Mul1 expression, which is a key step on preserving contractile property of sensory innervated SKM cells. Mul1 overexpression interfered with the balance between mitochondrial fusion and fission and was a key node for blocking the effects of IGF-1 that preserved the contractility of sensory-innervated SKM cells. Activation of AMP-activated protein kinase α (AMPKα), a mitochondrial downstream target, could block the effects of IGF-1. These data provide novel evidence that might be applied when searching for new approaches to improve the functional condition of long-term denervated SKM cells by increasing sensory protection using the IGF-1 signalling system to modulate the balance between mitochondrial fusion and fission.
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Affiliation(s)
- Yuan Ding
- Department of Anatomy, Shandong University School of Medicine, Jinan 250012, China
| | - Jianmin Li
- Department of Orthopaedics, Shandong University Qilu Hospital, Jinan 250012, China
| | - Zhen Liu
- Department of Anatomy, Shandong University School of Medicine, Jinan 250012, China
| | - Huaxiang Liu
- Department of Rheumatology, Shandong University Qilu Hospital, Jinan 250012, China
| | - Hao Li
- Department of Orthopaedics, Shandong University Qilu Hospital, Jinan 250012, China
| | - Zhenzhong Li
- Department of Anatomy, Shandong University School of Medicine, Jinan 250012, China
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123
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Ruven C, Li W, Li H, Wong WM, Wu W. Transplantation of Embryonic Spinal Cord Derived Cells Helps to Prevent Muscle Atrophy after Peripheral Nerve Injury. Int J Mol Sci 2017; 18:ijms18030511. [PMID: 28264437 PMCID: PMC5372527 DOI: 10.3390/ijms18030511] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 02/10/2017] [Accepted: 02/22/2017] [Indexed: 02/07/2023] Open
Abstract
Injuries to peripheral nerves are frequent in serious traumas and spinal cord injuries. In addition to surgical approaches, other interventions, such as cell transplantation, should be considered to keep the muscles in good condition until the axons regenerate. In this study, E14.5 rat embryonic spinal cord fetal cells and cultured neural progenitor cells from different spinal cord segments were injected into transected musculocutaneous nerve of 200–300 g female Sprague Dawley (SD) rats, and atrophy in biceps brachii was assessed. Both kinds of cells were able to survive, extend their axons towards the muscle and form neuromuscular junctions that were functional in electromyographic studies. As a result, muscle endplates were preserved and atrophy was reduced. Furthermore, we observed that the fetal cells had a better effect in reducing the muscle atrophy compared to the pure neural progenitor cells, whereas lumbar cells were more beneficial compared to thoracic and cervical cells. In addition, fetal lumbar cells were used to supplement six weeks delayed surgical repair after the nerve transection. Cell transplantation helped to preserve the muscle endplates, which in turn lead to earlier functional recovery seen in behavioral test and electromyography. In conclusion, we were able to show that embryonic spinal cord derived cells, especially the lumbar fetal cells, are beneficial in the treatment of peripheral nerve injuries due to their ability to prevent the muscle atrophy.
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Affiliation(s)
- Carolin Ruven
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China.
| | - Wen Li
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China.
| | - Heng Li
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China.
| | - Wai-Man Wong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China.
| | - Wutian Wu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China.
- State Key Laboratory of Brain and Cognitive Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
- Joint Laboratory for CNS Regeneration, Jinan University and The University of Hong Kong, GHM Institute of CNS Regeneration, Jinan University, Guangzhou 510000, China.
- Guangdong Engineering Research Center of Stem Cell Storage and Clinical Application, Saliai Stem Cell Science and Technology, Guangzhou 510000, China.
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124
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Lee G, Lim JY, Frontera WR. Apoptosis in young and old denervated rat skeletal muscle. Muscle Nerve 2016; 55:262-269. [DOI: 10.1002/mus.25221] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Gangpyo Lee
- Department of Rehabilitation Medicine; Seoul National University Bundang Hospital, Seoul National University College of Medicine; 82, Gumi-ro 173, Bundang-gu, Seongnam-si Gyeonggi-do 13620 Republic of Korea
| | - Jae-Young Lim
- Department of Rehabilitation Medicine; Seoul National University Bundang Hospital, Seoul National University College of Medicine; 82, Gumi-ro 173, Bundang-gu, Seongnam-si Gyeonggi-do 13620 Republic of Korea
| | - Walter R. Frontera
- Department of Physical Medicine and Rehabilitation; Vanderbilt University Medical Center; Nashville Tennessee USA
- Department of Physiology; University of Puerto Rico School of Medicine; San Juan Puerto Rico
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125
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Spendiff S, Vuda M, Gouspillou G, Aare S, Perez A, Morais JA, Jagoe RT, Filion ME, Glicksman R, Kapchinsky S, MacMillan NJ, Pion CH, Aubertin-Leheudre M, Hettwer S, Correa JA, Taivassalo T, Hepple RT. Denervation drives mitochondrial dysfunction in skeletal muscle of octogenarians. J Physiol 2016; 594:7361-7379. [PMID: 27619626 DOI: 10.1113/jp272487] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 08/31/2016] [Indexed: 01/26/2023] Open
Abstract
KEY POINTS Mitochondria are frequently implicated in the ageing of skeletal muscle, although the role of denervation in modulating mitochondrial function in ageing muscle is unknown. We show that increased sensitivity to apoptosis initiation occurs prior to evidence of persistent denervation and is thus a primary mitochondrial defect in ageing muscle worthy of therapeutic targeting. However, at more advanced age, mitochondrial function changes are markedly impacted by persistent sporadic myofibre denervation, suggesting the mitochondrion may be a less viable therapeutic target. ABSTRACT Experimental denervation modulates mitochondrial function, where changes in both reactive oxygen species (ROS) and sensitivity to permeability transition are implicated in the resultant muscle atrophy. Notably, although denervation occurs sporadically in ageing muscle, its impact on ageing muscle mitochondria is unknown. Because this information has important therapeutic implications concerning targeting the mitochondrion in ageing muscle, we examined mitochondrial function in skeletal muscle from four groups of humans, comprising two active (mean ± SD age: 23.7 ± 2.7 years and 71.2 ± 4.9 years) and two inactive groups (64.8 ± 3.1 years and 82.5 ± 4.8 years), and compared this with a murine model of sporadic denervation. We tested the hypothesis that, although some alterations of mitochondrial function in aged muscle are attributable to a primary organelle defect, mitochondrial dysfunction would be impacted by persistent denervation in advanced age. Both ageing in humans and sporadic denervation in mice increased mitochondrial sensitivity to permeability transition (humans, P = 0.004; mice, P = 0.01). To determine the contribution of sporadic denervation to mitochondrial function, we pharmacologically inhibited the denervation-induced ROS response. This reduced ROS emission by 60% (P = 0.02) in sporadically denervated mouse muscle, which is similar to that seen in humans older than 75 years (-66%, P = 0.02) but not those younger than 75 years. We conclude that an increased sensitivity to permeability transition is a primary mitochondrial defect in ageing muscle. However, at more advanced age, when muscle atrophy becomes more clinically severe, mitochondrial function changes are markedly impacted by persistent sporadic denervation, making the mitochondrion a less viable therapeutic target.
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Affiliation(s)
- Sally Spendiff
- Research Institute of the McGill University Health Centre, Montreal, Canada.,McGill Research Centre for Physical Activity & Health, McGill University, Montreal, Canada
| | - Madhusudanarao Vuda
- Research Institute of the McGill University Health Centre, Montreal, Canada.,McGill Research Centre for Physical Activity & Health, McGill University, Montreal, Canada
| | - Gilles Gouspillou
- Research Institute of the McGill University Health Centre, Montreal, Canada.,Present address: Department of Kinanthropologie, Universite du Quebec a Montreal, Montreal, Canada
| | - Sudhakar Aare
- Research Institute of the McGill University Health Centre, Montreal, Canada.,McGill Research Centre for Physical Activity & Health, McGill University, Montreal, Canada
| | - Anna Perez
- Research Institute of the McGill University Health Centre, Montreal, Canada
| | - José A Morais
- Division of Geriatric Medicine, McGill University, Montreal, Canada
| | - Robert T Jagoe
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Canada
| | - Marie-Eve Filion
- Department of Kinesiology & Physical Education, McGill University, Montreal, Canada
| | - Robin Glicksman
- Department of Kinesiology & Physical Education, McGill University, Montreal, Canada
| | - Sophia Kapchinsky
- Department of Kinesiology & Physical Education, McGill University, Montreal, Canada
| | - Norah J MacMillan
- Department of Kinesiology & Physical Education, McGill University, Montreal, Canada
| | - Charlotte H Pion
- Present address: Department of Kinanthropologie, Universite du Quebec a Montreal, Montreal, Canada
| | - Mylène Aubertin-Leheudre
- Present address: Department of Kinanthropologie, Universite du Quebec a Montreal, Montreal, Canada
| | | | - José A Correa
- Department of Mathematics and Statistics, McGill University, Montreal, Canada
| | - Tanja Taivassalo
- McGill Research Centre for Physical Activity & Health, McGill University, Montreal, Canada.,Department of Kinesiology & Physical Education, McGill University, Montreal, Canada
| | - Russell T Hepple
- Research Institute of the McGill University Health Centre, Montreal, Canada.,McGill Research Centre for Physical Activity & Health, McGill University, Montreal, Canada.,Department of Kinesiology & Physical Education, McGill University, Montreal, Canada
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126
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Mosole S, Carraro U, Kern H, Loefler S, Zampieri S. Use it or Lose It: Tonic Activity of Slow Motoneurons Promotes Their Survival and Preferentially Increases Slow Fiber-Type Groupings in Muscles of Old Lifelong Recreational Sportsmen. Eur J Transl Myol 2016; 26:5972. [PMID: 28078066 PMCID: PMC5220213 DOI: 10.4081/ejtm.2016.5972] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Histochemistry, immuno-histochemistry, gel electrophoresis of single muscle fibers and electromyography of aging muscles and nerves suggest that: i) denervation contributes to muscle atrophy, ii) impaired mobility accelerates the process, and iii) lifelong running protects against loss of motor units. Recent corroborating results on the muscle effects of Functional Electrical Stimulation (FES) of aged muscles will be also mentioned, but we will in particular discuss how and why a lifelong increased physical activity sustains reinnervation of muscle fibers. By analyzing distribution and density of muscle fibers co-expressing fast and slow Myosin Heavy Chains (MHC) we are able to distinguish the transforming muscle fibers due to activity related plasticity, to those that adapt muscle fiber properties to denervation and reinnervation. In muscle biopsies from septuagenarians with a history of lifelong high-level recreational activity we recently observed in comparison to sedentary seniors: 1. decreased proportion of small-size angular myofibers (denervated muscle fibers); 2. considerable increase of fiber-type groupings of the slow type (reinnervated muscle fibers); 3. sparse presence of muscle fibers co-expressing fast and slow MHC. Immuno-histochemical characteristics fluctuate from those with scarce fiber-type modulation and groupings to almost complete transformed muscles, going through a process in which isolated fibers co-expressing fast and slow MHC fill the gaps among fiber groupings. Data suggest that lifelong high-level exercise allows the body to adapt to the consequences of the age-related denervation and that it preserves muscle structure and function by saving otherwise lost muscle fibers through recruitment to different slow motor units. This is an opposite behavior of that described in long term denervated or resting muscles. These effects of lifelong high level activity seems to act primarily on motor neurons, in particular on those always more active, i.e., on the slow motoneurons. The preferential reinnervation that follows along decades of increased activity maintains neuron and myofibers. All together the results open interesting perspectives for applications of FES and electroceuticals for rejuvenation of aged muscles to delay functional decline and loss of independence that are unavoidable burdens of advanced aging. TRIAL REGISTRATION ClinicalTrials.gov: NCT01679977.
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Affiliation(s)
- Simone Mosole
- Laboratory of Translation Myology, Department of Biomedical Sciences, University of Padova, Italy
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | - Ugo Carraro
- IRCCS Fondazione Ospedale San Camillo, Venice, Italy
| | - Helmut Kern
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
- Department of Physical Medicine and Rehabilitation, Wilhelminenspital, Vienna, Austria
| | - Stefan Loefler
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | - Sandra Zampieri
- Laboratory of Translation Myology, Department of Biomedical Sciences, University of Padova, Italy
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
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127
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Age-Associated Changes in the Spectral and Statistical Parameters of Surface Electromyogram of Tibialis Anterior. BIOMED RESEARCH INTERNATIONAL 2016; 2016:7159701. [PMID: 27610379 PMCID: PMC5005778 DOI: 10.1155/2016/7159701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/15/2016] [Accepted: 07/19/2016] [Indexed: 01/10/2023]
Abstract
Age-related neuromuscular change of Tibialis Anterior (TA) is a leading cause of muscle strength decline among the elderly. This study has established the baseline for age-associated changes in sEMG of TA at different levels of voluntary contraction. We have investigated the use of Gaussianity and maximal power of the power spectral density (PSD) as suitable features to identify age-associated changes in the surface electromyogram (sEMG). Eighteen younger (20–30 years) and 18 older (60–85 years) cohorts completed two trials of isometric dorsiflexion at four different force levels between 10% and 50% of the maximal voluntary contraction. Gaussianity and maximal power of the PSD of sEMG were determined. Results show a significant increase in sEMG's maximal power of the PSD and Gaussianity with increase in force for both cohorts. It was also observed that older cohorts had higher maximal power of the PSD and lower Gaussianity. These age-related differences observed in the PSD and Gaussianity could be due to motor unit remodelling. This can be useful for noninvasive tracking of age-associated neuromuscular changes.
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128
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Aare S, Spendiff S, Vuda M, Elkrief D, Perez A, Wu Q, Mayaki D, Hussain SNA, Hettwer S, Hepple RT. Failed reinnervation in aging skeletal muscle. Skelet Muscle 2016; 6:29. [PMID: 27588166 PMCID: PMC5007704 DOI: 10.1186/s13395-016-0101-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 08/05/2016] [Indexed: 12/08/2023] Open
Abstract
BACKGROUND Skeletal muscle displays a marked accumulation of denervated myofibers at advanced age, which coincides with an acceleration of muscle atrophy. METHODS In this study, we evaluated the hypothesis that the accumulation of denervated myofibers in advanced age is due to failed reinnervation by examining muscle from young adult (YA) and very old (VO) rats and from a murine model of sporadic denervation secondary to neurotrypsin over-expression (Sarco mouse). RESULTS Both aging rat muscle and Sarco mouse muscle exhibited marked fiber-type grouping, consistent with repeating cycles of denervation and reinnervation, yet in VO muscle, rapsyn at the endplate increased and was associated with only a 10 % decline in acetylcholine receptor (AChR) intensity, whereas in Sarco mice, there was a decline in rapsyn and a 25 % decrease in AChR intensity. Transcripts of muscle-specific kinase (21-fold), acetylcholine receptor subunits α (68-fold), ε (threefold) and γ (47-fold), neural cell adhesion molecule (66-fold), and runt-related transcription factor 1 (33-fold) were upregulated in VO muscle of the rat, consistent with the marked persistent denervation evidenced by a large proportion of very small fibers (>20 %). In the Sarco mice, there were much smaller increases in denervation transcripts (0-3.5-fold) and accumulation of very small fibers (2-6 %) compared to the VO rat, suggesting a reduced capacity for reinnervation in aging muscle. Despite the marked persistent denervation in the VO rat muscle, transcripts of neurotrophins involved in promoting axonal sprouting following denervation exhibited no increase, and several miRNAs predicted to suppress neurotrophins were elevated in VO rat. CONCLUSIONS Our results support the hypothesis that the accumulation of denervated fibers with aging is due to failed reinnervation and that this may be affected by a limited neurotrophin response that mediates axonal sprouting following denervation.
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Affiliation(s)
- Sudhakar Aare
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1 ; McGill Research Centre for Physical Activity and Health, McGill University, Montreal, QC Canada
| | - Sally Spendiff
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1 ; McGill Research Centre for Physical Activity and Health, McGill University, Montreal, QC Canada
| | - Madhusudanarao Vuda
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1 ; McGill Research Centre for Physical Activity and Health, McGill University, Montreal, QC Canada
| | - Daren Elkrief
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1 ; McGill Research Centre for Physical Activity and Health, McGill University, Montreal, QC Canada ; Department of Kinesiology and Physical Education, McGill University, Montreal, QC Canada
| | - Anna Perez
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1
| | - Qinghua Wu
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1 ; McGill Research Centre for Physical Activity and Health, McGill University, Montreal, QC Canada
| | - Dominique Mayaki
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1
| | - Sabah N A Hussain
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1
| | | | - Russell T Hepple
- Research Institute of the McGill University Health Centre, EM2.2232, RI MUHC, 1001 Decarie Blvd, Montreal, QC Canada H4A 3J1 ; McGill Research Centre for Physical Activity and Health, McGill University, Montreal, QC Canada ; Department of Kinesiology and Physical Education, McGill University, Montreal, QC Canada
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129
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Hepple RT. Impact of aging on mitochondrial function in cardiac and skeletal muscle. Free Radic Biol Med 2016; 98:177-186. [PMID: 27033952 DOI: 10.1016/j.freeradbiomed.2016.03.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/12/2016] [Indexed: 12/13/2022]
Abstract
Both skeletal muscle and cardiac muscle are subject to marked structural and functional impairment with aging and these changes contribute to the reduced capacity for exercise as we age. Since mitochondria are involved in multiple aspects of cellular homeostasis including energetics, reactive oxygen species signaling, and regulation of intrinsic apoptotic pathways, defects in this organelle are frequently implicated in the deterioration of skeletal and cardiac muscle with aging. On this basis, the purpose of this review is to evaluate the evidence that aging causes dysfunction in mitochondria in striated muscle with a view towards drawing conclusions about the potential of these changes to contribute to the deterioration seen in striated muscle with aging. As will be shown, impairment in respiration and reactive oxygen species emission with aging are highly variable between studies and seem to be largely a consequence of physical inactivity. On the other hand, both skeletal and cardiac muscle mitochondria are more susceptible to permeability transition and this seems a likely cause of the increased recruitment of mitochondrial-mediated pathways of apoptosis seen in striated muscle. The review concludes by examining the role of degeneration of mitochondrial DNA versus impaired mitochondrial quality control mechanisms in the accumulation of mitochondria that are sensitized to permeability transition, whereby the latter mechanism is favored as the most likely cause.
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Affiliation(s)
- R T Hepple
- Department of Kinesiology, Centre for Translational Biology, McGill University Health Center, Canada; Meakins Christie Laboratories, Canada; Department of Medicine, McGill University, Canada
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130
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Sierra E, Espinosa de Los Monteros A, Fernández A, Díaz-Delgado J, Suárez-Santana C, Arbelo M, Sierra MA, Herráez P. Muscle Pathology in Free-Ranging Stranded Cetaceans. Vet Pathol 2016; 54:298-311. [PMID: 27538973 DOI: 10.1177/0300985816660747] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Despite the profound impact that skeletal muscle disorders may pose for the daily activities of wild terrestrial and marine mammals, such conditions have been rarely described in cetaceans. In this study, the authors aimed to determine the nature and prevalence of skeletal muscle lesions in small and large odontocetes and mysticetes ( n = 153) from 19 different species. A macroscopic evaluation of the epaxial muscle mass and a histologic examination of the longissimus dorsi muscle were performed in all cases. The only macroscopically evident change was variable degrees of atrophy of the epaxial muscles ( longissimus dorsi, multifidus, spinalis) in emaciated specimens. The histopathological study revealed single or combined morphological changes in 91.5% of the cases. These changes included the following: degenerative lesions (75.2%), muscle atrophy (37.9%), chronic myopathic changes (25.5%), parasitic infestation (9.2%), and myositis (1.9%). The skeletal muscle is easily sampled during a necropsy and provides essential microscopic information that reflects both local and systemic conditions. Thus, skeletal muscle should be systematically sampled, processed, and examined in all stranded cetaceans.
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Affiliation(s)
- E Sierra
- 1 Department of Veterinary Pathology, Institute for Animal Health, Veterinary School, University of Las Palmas de Gran Canaria, Arucas, Spain
| | - A Espinosa de Los Monteros
- 1 Department of Veterinary Pathology, Institute for Animal Health, Veterinary School, University of Las Palmas de Gran Canaria, Arucas, Spain
| | - A Fernández
- 1 Department of Veterinary Pathology, Institute for Animal Health, Veterinary School, University of Las Palmas de Gran Canaria, Arucas, Spain
| | - J Díaz-Delgado
- 1 Department of Veterinary Pathology, Institute for Animal Health, Veterinary School, University of Las Palmas de Gran Canaria, Arucas, Spain
| | - C Suárez-Santana
- 1 Department of Veterinary Pathology, Institute for Animal Health, Veterinary School, University of Las Palmas de Gran Canaria, Arucas, Spain
| | - M Arbelo
- 1 Department of Veterinary Pathology, Institute for Animal Health, Veterinary School, University of Las Palmas de Gran Canaria, Arucas, Spain
| | - M A Sierra
- 2 Department of Anatomy and Comparative Pathology, Veterinary Faculty, University of Córdoba, Córdoba, Spain
| | - P Herráez
- 1 Department of Veterinary Pathology, Institute for Animal Health, Veterinary School, University of Las Palmas de Gran Canaria, Arucas, Spain
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131
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Siddiqi A, Arjunan SP, Kumar DK. Difference in age-related changes in surface electromyogram of tibialis anterior and triceps surae. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/4/045019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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132
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Grosicki GJ, Standley RA, Murach KA, Raue U, Minchev K, Coen PM, Newman AB, Cummings S, Harris T, Kritchevsky S, Goodpaster BH, Trappe S. Improved single muscle fiber quality in the oldest-old. J Appl Physiol (1985) 2016; 121:878-884. [PMID: 27516537 DOI: 10.1152/japplphysiol.00479.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/04/2016] [Indexed: 01/06/2023] Open
Abstract
We examined single muscle fiber contractile function of the oldest-old (3F/2M, 89 ± 1 yr old) enrolled in The Health, Aging, and Body Composition Study (The Health ABC Study). Vastus lateralis muscle biopsies were obtained and single muscle fiber function was determined (n = 105) prior to myosin heavy chain (MHC) isoform identification with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cross-sectional area of MHC I muscle fibers (5,576 ± 333 μm2; n = 58) was 21% larger (P < 0.05) than MHC IIa fibers (4,518 ± 386 μm2; n = 47). Normalized power (an indicator of muscle fiber quality incorporating size, strength, and speed) of MHC I and IIa muscle fibers was 2.3 ± 0.1 and 17.4 ± 0.8 W/l, respectively. Compared with previous research from our lab using identical procedures, MHC I normalized power was 28% higher than healthy 20 yr olds and similar to younger octogenarians (∼80 yr old). Normalized power of MHC IIa fibers was 63% greater than 20 yr olds and 39% greater than younger octogenarians. These comparative data suggest that power output per unit size (i.e., muscle quality) of remaining muscle fibers improves with age, a phenomenon more pronounced in MHC IIa fibers. Age-related single muscle fiber quality improvements may be a compensatory mechanism to help offset decrements in whole muscle function.
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Affiliation(s)
- Greg J Grosicki
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Robert A Standley
- Translational Research Institute for Metabolism and Diabetes, Orlando, Florida
| | - Kevin A Murach
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Ulrika Raue
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Kiril Minchev
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Paul M Coen
- Translational Research Institute for Metabolism and Diabetes, Orlando, Florida
| | - Anne B Newman
- Center for Aging and Population Health, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Steven Cummings
- California Pacific Medical Center Research Institute, San Francisco, California
| | - Tamara Harris
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Maryland; and
| | - Stephen Kritchevsky
- Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Bret H Goodpaster
- Translational Research Institute for Metabolism and Diabetes, Orlando, Florida
| | - Scott Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana;
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133
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Frank-Wilson AW, Farthing JP, Chilibeck PD, Arnold CM, Davison KS, Olszynski WP, Kontulainen SA. Lower leg muscle density is independently associated with fall status in community-dwelling older adults. Osteoporos Int 2016; 27:2231-2240. [PMID: 26879201 DOI: 10.1007/s00198-016-3514-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 02/02/2016] [Indexed: 12/25/2022]
Abstract
UNLABELLED Muscle density is a risk factor for fractures in older adults; however, its association with falls is not well described. After adjusting for biologically relevant confounding factors, a unit decrease in muscle density was associated with a 17 % increase in odds of reporting a fall, independent of functional mobility. INTRODUCTION Falls are the leading cause of injury, disability, and fractures in older adults. Low muscle density (i.e., caused by muscle adiposity) and functional mobility have been identified as risk factors for incident disability and fractures in older adults; however, it is not known if these are also independently associated with falls. The purpose of this study was to explore the associations of muscle density and functional mobility with fall status. METHODS Cross-sectional observational study of 183 men and women aged 60-98 years. Descriptive data, including a 12-month fall recall, Timed Up and Go (TUG) test performance, lower leg muscle area, and density. Odds ratio (OR) of being a faller were calculated, adjusted for age, sex, body mass index, general health status, diabetes, and comorbidities. RESULTS Every mg/cm(3) increase in muscle density (mean 70.2, SD 2.6 mg/cm(3)) independently reduced the odds of being a faller by 19 % (OR 0.81 [95 % CI 0.67 to 0.97]), and every 1 s longer TUG test time (mean 9.8, SD 2.6 s) independently increased the odds by 17 % (OR 1.17 [95 % CI 1.01 to 1.37]). When both muscle density and TUG test time were included in the same model, only age (OR 0.93 [95 % CI 0.87 to 0.99]) and muscle density (OR 0.83 [95 % CI 0.69 to 0.99]) were independently associated with fall status. CONCLUSIONS Muscle density was associated with fall status, independent of functional mobility. Muscle density may compliment functional mobility tests as a biometric outcome for assessing fall risk in well-functioning older adults.
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Affiliation(s)
- A W Frank-Wilson
- College of Kinesiology, University of Saskatchewan, 87 Campus Drive, Saskatoon, SK, S7N5B2, Canada.
| | - J P Farthing
- College of Kinesiology, University of Saskatchewan, 87 Campus Drive, Saskatoon, SK, S7N5B2, Canada
| | - P D Chilibeck
- College of Kinesiology, University of Saskatchewan, 87 Campus Drive, Saskatoon, SK, S7N5B2, Canada
| | - C M Arnold
- School of Physical Therapy, University of Saskatchewan, Saskatoon, SK, Canada
| | - K S Davison
- University of Victoria, Victoria, BC, Canada
- Saskatoon Osteoporosis and CaMOs Centre, Saskatoon, SK, Canada
| | - W P Olszynski
- Saskatoon Osteoporosis and CaMOs Centre, Saskatoon, SK, Canada
- College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - S A Kontulainen
- College of Kinesiology, University of Saskatchewan, 87 Campus Drive, Saskatoon, SK, S7N5B2, Canada.
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134
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Exercise Promotes Healthy Aging of Skeletal Muscle. Cell Metab 2016; 23:1034-1047. [PMID: 27304505 PMCID: PMC5045036 DOI: 10.1016/j.cmet.2016.05.007] [Citation(s) in RCA: 292] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/18/2016] [Accepted: 05/24/2016] [Indexed: 02/08/2023]
Abstract
Primary aging is the progressive and inevitable process of bodily deterioration during adulthood. In skeletal muscle, primary aging causes defective mitochondrial energetics and reduced muscle mass. Secondary aging refers to additional deleterious structural and functional age-related changes caused by diseases and lifestyle factors. Secondary aging can exacerbate deficits in mitochondrial function and muscle mass, concomitant with the development of skeletal muscle insulin resistance. Exercise opposes deleterious effects of secondary aging by preventing the decline in mitochondrial respiration, mitigating aging-related loss of muscle mass and enhancing insulin sensitivity. This review focuses on mechanisms by which exercise promotes "healthy aging" by inducing modifications in skeletal muscle.
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135
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Rygiel KA, Picard M, Turnbull DM. The ageing neuromuscular system and sarcopenia: a mitochondrial perspective. J Physiol 2016; 594:4499-512. [PMID: 26921061 PMCID: PMC4983621 DOI: 10.1113/jp271212] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/14/2015] [Indexed: 12/15/2022] Open
Abstract
Skeletal muscles undergo structural and functional decline with ageing, culminating in sarcopenia. The underlying neuromuscular mechanisms have been the subject of intense investigation, revealing mitochondrial abnormalities as potential culprits within both nerve and muscle cells. Implicated mechanisms involve impaired mitochondrial dynamics, reduced organelle biogenesis and quality control via mitophagy, accumulation of mitochondrial DNA (mtDNA) damage and respiratory chain defect, metabolic disturbance, pro-apoptotic signalling, and oxidative stress. This article provides an overview of the cellular mechanisms whereby mitochondria may promote maladaptive changes within motor neurons, the neuromuscular junction (NMJ) and muscle fibres. Lifelong physical activity, which promotes mitochondrial health across tissues, is emerging as an effective countermeasure for sarcopenia.
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Affiliation(s)
- Karolina A Rygiel
- Newcastle University Centre for Ageing and Vitality, Newcastle upon Tyne, UK.,Wellcome Trust Centre for Mitochondrial Research, Newcastle upon Tyne, UK
| | - Martin Picard
- Division of Behavioral Medicine, Department of Psychiatry, College of Physicians and Surgeons, Columbia University, Columbia University Medical Center, New York, NY, USA
| | - Doug M Turnbull
- Newcastle University Centre for Ageing and Vitality, Newcastle upon Tyne, UK.,Wellcome Trust Centre for Mitochondrial Research, Newcastle upon Tyne, UK
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136
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McDonagh B, Scullion SM, Vasilaki A, Pollock N, McArdle A, Jackson MJ. Ageing-induced changes in the redox status of peripheral motor nerves imply an effect on redox signalling rather than oxidative damage. Free Radic Biol Med 2016; 94:27-35. [PMID: 26876649 PMCID: PMC4851218 DOI: 10.1016/j.freeradbiomed.2016.02.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/02/2016] [Accepted: 02/05/2016] [Indexed: 01/17/2023]
Abstract
Ageing is associated with loss of skeletal muscle fibres, atrophy of the remaining fibres and weakness. These changes in muscle are accompanied by disruption of motor neurons and neuromuscular junctions although the direct relationship between the nerve and muscle degeneration is not understood. Oxidative changes have been implicated in the mechanisms leading to age-related loss of muscle mass and in degeneration of the central nervous system, but little is known about age-related changes in oxidation in specific peripheral nerves that supply muscles that are affected by ageing. We have therefore examined the sciatic nerve of old mice at an age when loss of tibialis anterior muscle mass and function is apparent. Sciatic nerve from old mice did not show a gross increase in oxidative damage, but electron paramagnetic resonance (EPR) studies indicated an increase in the activity of superoxide and/or peroxynitrite in the nerves of old mice at rest that was further exacerbated by electrical stimulation of the nerve to activate muscle contractions. Proteomic analyses indicated that specific redox-sensitive proteins are increased in content in the nerves of old mice that may reflect an adaptation to regulate the increased superoxide/peroxynitrite and maintain redox homoeostasis. Analysis of redox active cysteines showed some increase in reversible oxidation in specific proteins in nerves of old mice, but this was not universally seen across all redox-active cysteines. Detailed analysis of the redox-active cysteine in one protein in the nerve of old mice that is key to redox signalling (Peroxiredoxin 6, Cys 47) showed a minor increase in reversible oxidation that would be compatible with a change in its redox signalling function. In conclusion, the data presented indicate that sciatic nerve from old mice does not show a gross increase in oxidative damage similar to that seen in the TA and other muscles that it innervates. Our results indicate an adaptation to increased oxidation with minor changes in the oxidation of key cysteines that may contribute to defective redox signalling in the nerve.
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Key Words
- cp, 3-carboxy-proxyl
- cph, 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine
- nav1.5, voltage gated sodium channel isoform
- ncam, neural cell adhesion molecule
- nem, n-ethylmaleimide
- nmj, neuromuscular junction
- nox2, nad(p)h oxidase 2
- prdx, peroxiredoxin
- sod1, cuzn superoxide dismutase
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Affiliation(s)
- Brian McDonagh
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK
| | - Siobhan M Scullion
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK
| | - Aphrodite Vasilaki
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK
| | - Natalie Pollock
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK
| | - Anne McArdle
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK
| | - Malcolm J Jackson
- MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK.
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137
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Age- and Activity-Related Differences in the Abundance of Myosin Essential and Regulatory Light Chains in Human Muscle. Proteomes 2016; 4:proteomes4020015. [PMID: 28248225 PMCID: PMC5217348 DOI: 10.3390/proteomes4020015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 12/21/2022] Open
Abstract
Traditional methods for phenotyping skeletal muscle (e.g., immunohistochemistry) are labor-intensive and ill-suited to multixplex analysis, i.e., assays must be performed in a series. Addressing these concerns represents a largely unmet research need but more comprehensive parallel analysis of myofibrillar proteins could advance knowledge regarding age- and activity-dependent changes in human muscle. We report a label-free, semi-automated and time efficient LC-MS proteomic workflow for phenotyping the myofibrillar proteome. Application of this workflow in old and young as well as trained and untrained human skeletal muscle yielded several novel observations that were subsequently verified by multiple reaction monitoring (MRM). We report novel data demonstrating that human ageing is associated with lesser myosin light chain 1 content and greater myosin light chain 3 content, consistent with an age-related reduction in type II muscle fibers. We also disambiguate conflicting data regarding myosin regulatory light chain, revealing that age-related changes in this protein more closely reflect physical activity status than ageing per se. This finding reinforces the need to control for physical activity levels when investigating the natural process of ageing. Taken together, our data confirm and extend knowledge regarding age- and activity-related phenotypes. In addition, the MRM transitions described here provide a methodological platform that can be fine-tuned to suite multiple research needs and thus advance myofibrillar phenotyping.
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Costagliola A, Wojcik S, Pagano TB, De Biase D, Russo V, Iovane V, Grieco E, Papparella S, Paciello O. Age-Related Changes in Skeletal Muscle of Cattle. Vet Pathol 2016; 53:436-46. [PMID: 26869152 DOI: 10.1177/0300985815624495] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sarcopenia, the age-related loss of muscle mass and strength, is a multifactorial condition that represents a major healthcare concern for the elderly population. Although its morphologic features have been extensively studied in humans, animal models, and domestic and wild animals, only a few reports about spontaneous sarcopenia exist in other long-lived animals. In this work, muscle samples from 60 healthy Podolica-breed old cows (aged 15-23 years) were examined and compared with muscle samples from 10 young cows (3-6 years old). Frozen sections were studied through standard histologic and histoenzymatic procedures, as well as by immunohistochemistry, immunofluorescence, and Western blot analysis. The most prominent age-related myopathic features seen in the studied material included angular fiber atrophy (90% of cases), mitochondrial alterations (ragged red fibers, 70%; COX-negative fibers, 60%), presence of vacuolated fibers (75%), lymphocytic (predominantly CD8+) inflammation (40%), and type II selective fiber atrophy (40%). Immunohistochemistry revealed increased expression of major histocompatibility complex I in 36 cases (60%) and sarcoplasmic accumulations of β-amyloid precursor protein-positive material in 18 cases (30%). In aged cows, muscle atrophy was associated with accumulation of myostatin. Western blot analysis indicated increased amount of both proteins-myostatin and β-amyloid precursor protein-in muscles of aged animals compared with controls. These findings confirm the presence of age-related morphologic changes in cows similar to human sarcopenia and underline the possible role of amyloid deposition and subsequent inflammation in muscle senescence.
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Affiliation(s)
- A Costagliola
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - S Wojcik
- Department of Anatomy and Neurobiology, Medical University of Gdansk, Gdansk, Poland
| | - T B Pagano
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - D De Biase
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - V Russo
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - V Iovane
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - E Grieco
- Azienda Sanitaria Locale, Salerno, Italy
| | - S Papparella
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - O Paciello
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
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139
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Siddiqi A, Kumar D, Arjunan S. Age-related motor unit remodeling in the Tibialis Anterior. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:6090-3. [PMID: 26737681 DOI: 10.1109/embc.2015.7319781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Limited studies exist on the use of surface electromyogram (EMG) signal features to detect age-related motor unit remodeling in the Tibialis Anterior. Motor unit remodeling leads to declined muscle strength and force steadiness during submaximal contractions which are factors for risk of falls in the elderly. This study investigated the remodeling phenomena in the Tibialis Anterior using sample entropy and higher order statistics. Eighteen young (26.1 ± 2.9 years) and twelve elderly (68.7 ± 9.0 years) participants performed isometric dorsiflexion of the ankle at 20% maximal voluntary contraction (MVC) and their Tibialis Anterior (TA) EMG was recorded. Sample entropy, Gaussianity and Linearity Test statistics were calculated from the recorded EMG for each MVC. Shapiro-Wilk test was used to determine normality, and either a two-tail student t-test or Wilcoxon rank sum test was performed to determine significant difference in the EMG features between the young and old cohorts. Results show age-related motor unit remodeling to be depicted by decreased sample entropy (p <; 0.1), increased non-Gaussianity (p <; 0.05) and lesser degree of linearity in the elderly. This is due to the increased sparsity of the MUAPs as a result of the denervation-reinnervation process, and the decrease in total number of motor units.
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140
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Karampatos S, Papaioannou A, Beattie KA, Maly MR, Chan A, Adachi JD, Pritchard JM. The reliability of a segmentation methodology for assessing intramuscular adipose tissue and other soft-tissue compartments of lower leg MRI images. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2015; 29:237-44. [PMID: 26702939 DOI: 10.1007/s10334-015-0510-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/06/2015] [Accepted: 11/06/2015] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Determine the reliability of a magnetic resonance (MR) image segmentation protocol for quantifying intramuscular adipose tissue (IntraMAT), subcutaneous adipose tissue, total muscle and intermuscular adipose tissue (InterMAT) of the lower leg. MATERIALS AND METHODS Ten axial lower leg MRI slices were obtained from 21 postmenopausal women using a 1 Tesla peripheral MRI system. Images were analyzed using sliceOmatic™ software. The average cross-sectional areas of the tissues were computed for the ten slices. Intra-rater and inter-rater reliability were determined and expressed as the standard error of measurement (SEM) (absolute reliability) and intraclass coefficient (ICC) (relative reliability). RESULTS Intra-rater and inter-rater reliability for IntraMAT were 0.991 (95% confidence interval [CI] 0.978-0.996, p < 0.05) and 0.983 (95% CI 0.958-9.993, p < 0.05), respectively. For the other soft tissue compartments, the ICCs were all >0.90 (p < 0.05). The absolute intra-rater and inter-rater reliability (expressed as SEM) for segmenting IntraMAT were 22.19 mm(2) (95% CI 16.97-32.04) and 78.89 mm(2) (95% CI 60.36-113.92), respectively. CONCLUSION This is a reliable segmentation protocol for quantifying IntraMAT and other soft-tissue compartments of the lower leg. A standard operating procedure manual is provided to assist users, and SEM values can be used to estimate sample size and determine confidence in repeated measurements in future research.
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Affiliation(s)
- Sarah Karampatos
- Department of Medicine, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada. .,Juravinski Research Centre, Geriatric Education and Research in the Aging Sciences (GERAS) Centre, 88 Maplewood Avenue, Hamilton, ON, L8M 1W9, Canada. .,Department of Rehabilitation Sciences, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada.
| | - Alexandra Papaioannou
- Department of Medicine, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada.,Juravinski Research Centre, Geriatric Education and Research in the Aging Sciences (GERAS) Centre, 88 Maplewood Avenue, Hamilton, ON, L8M 1W9, Canada.,Department of Biostatistics and Epidemiology, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
| | - Karen A Beattie
- Department of Medicine, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
| | - Monica R Maly
- Department of Rehabilitation Sciences, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
| | - Adrian Chan
- Faculty of Health Sciences, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
| | - Jonathan D Adachi
- Department of Medicine, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
| | - Janet M Pritchard
- Department of Medicine, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada.,Juravinski Research Centre, Geriatric Education and Research in the Aging Sciences (GERAS) Centre, 88 Maplewood Avenue, Hamilton, ON, L8M 1W9, Canada
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141
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Hepple RT, Rice CL. Innervation and neuromuscular control in ageing skeletal muscle. J Physiol 2015; 594:1965-78. [PMID: 26437581 DOI: 10.1113/jp270561] [Citation(s) in RCA: 209] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 09/28/2015] [Indexed: 12/28/2022] Open
Abstract
Changes in the neuromuscular system affecting the ageing motor unit manifest structurally as a reduction in motor unit number secondary to motor neuron loss; fibre type grouping due to repeating cycles of denervation-reinnervation; and instability of the neuromuscular junction that may be due to either or both of a gradual perturbation in postsynaptic signalling mechanisms necessary for maintenance of the endplate acetylcholine receptor clusters or a sudden process involving motor neuron death or traumatic injury to the muscle fibre. Functionally, these changes manifest as a reduction in strength and coordination that precedes a loss in muscle mass and contributes to impairments in fatigue. Regular muscle activation in postural muscles or through habitual physical activity can attenuate some of these structural and functional changes up to a point along the ageing continuum. On the other hand, regular muscle activation in advanced age (>75 years) loses its efficacy, and at least in rodents may exacerbate age-related motor neuron death. Transgenic mouse studies aimed at identifying potential mechanisms of motor unit disruptions in ageing muscle are not conclusive due to many different mechanisms converging on similar motor unit alterations, many of which phenocopy ageing muscle. Longitudinal studies of ageing models and humans will help clarify the cause and effect relationships and thus, identify relevant therapeutic targets to better preserve muscle function across the lifespan.
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Affiliation(s)
- Russell T Hepple
- Department of Kinesiology & Physical Education, McGill University, Montreal, Québec, Canada.,McGill Research Centre for Physical Activity and Health, Montreal, Québec, Canada.,Centre for Translational Biology, Research Institute of the McGill University Health Centre, Montreal, Québec, Canada
| | - Charles L Rice
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada.,Canadian Centre for Activity and Aging, London, Ontario, Canada.,Department of Anatomy & Cell Biology, University of Western Ontario, London, Ontario, Canada
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142
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Gillon A, Sheard P. Elderly mouse skeletal muscle fibres have a diminished capacity to upregulate NCAM production in response to denervation. Biogerontology 2015; 16:811-23. [PMID: 26385499 DOI: 10.1007/s10522-015-9608-6] [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: 08/10/2015] [Accepted: 09/14/2015] [Indexed: 01/17/2023]
Abstract
Sarcopenia is a major contributor to the loss of independence and deteriorating quality of life in elderly individuals, it manifests as a decline in skeletal muscle mass and strength beyond the age of 65. Muscle fibre atrophy is a major contributor to sarcopenia and the most severely atrophic fibres are commonly found in elderly muscles to have permanently lost their motor nerve input. By contrast with elderly fibres, when fibres in young animals lose their motor input they normally mount a response to induce restoration of nerve contact, and this is mediated in part by upregulated expression of the nerve cell adhesion molecule (NCAM). Therefore, skeletal muscles appear to progressively lose their ability to become reinnervated, and here we have investigated whether this decline occurs via loss of the muscle's ability to upregulate NCAM in response to denervation. We performed partial denervation (by peripheral nerve crush) of the extensor digitorum longus muscle of the lower limb in both young and elderly mice. We used immunohistochemistry to compare relative NCAM levels at denervated and control innervated muscle fibres, focused on measurements at neuromuscular junctional, extra-junctional and cytoplasmic locations. Muscle fibres in young animals responded to denervation with significant (32.9%) increases in unpolysialylated NCAM at extra-junctional locations, but with no change in polysialylated NCAM. The same partial denervation protocol applied to elderly animals resulted in no significant change in either polysialylated or unpolysialylated NCAM at junctional, extra-junctional or cytoplasmic locations, therefore muscle fibres in young mice upregulated NCAM in response to denervation but fibres in elderly mice failed to do so. Elevation of NCAM levels is likely to be an important component of the muscle fibre's ability to attract or reattract a neural input, so we conclude that the presence of increasing numbers of long-term denervated fibres in elderly muscles is due, at least in part, to the fibre's declining ability to mount a normal response to loss of motor input.
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Affiliation(s)
- Ashley Gillon
- Department of Physiology, Otago School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
| | - Philip Sheard
- Department of Physiology, Otago School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
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143
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Liu W, Wei-LaPierre L, Klose A, Dirksen RT, Chakkalakal JV. Inducible depletion of adult skeletal muscle stem cells impairs the regeneration of neuromuscular junctions. eLife 2015; 4. [PMID: 26312504 PMCID: PMC4579298 DOI: 10.7554/elife.09221] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/26/2015] [Indexed: 01/01/2023] Open
Abstract
Skeletal muscle maintenance depends on motor innervation at neuromuscular junctions (NMJs). Multiple mechanisms contribute to NMJ repair and maintenance; however muscle stem cells (satellite cells, SCs), are deemed to have little impact on these processes. Therefore, the applicability of SC studies to attenuate muscle loss due to NMJ deterioration as observed in neuromuscular diseases and aging is ambiguous. We employed mice with an inducible Cre, and conditionally expressed DTA to deplete or GFP to track SCs. We found SC depletion exacerbated muscle atrophy and type transitions connected to neuromuscular disruption. Also, elevated fibrosis and further declines in force generation were specific to SC depletion and neuromuscular disruption. Fate analysis revealed SC activity near regenerating NMJs. Moreover, SC depletion aggravated deficits in reinnervation and post-synaptic morphology at regenerating NMJs. Therefore, our results propose a mechanism whereby further NMJ and skeletal muscle decline ensues upon SC depletion and neuromuscular disruption. DOI:http://dx.doi.org/10.7554/eLife.09221.001 New muscle fibers are made throughout our lives to replace those that have been damaged by normal wear and tear, and to meet new physical demands. These new muscle fibers develop from a pool of muscle stem cells. To create and maintain fully working muscles, nerve cells called motor neurons must also properly attach to the muscle fibers. These nerve cells transmit messages from the brain that tell the muscles what to do. If the muscle-nerve connections do not form correctly, or are severed, muscles can waste away. This may occur as part of a neuromuscular disease, and also happens to some extent as a normal part of aging. It was thought that muscle stem cells do not affect how the muscle-nerve connections form. By studying genetically engineered mice, Liu et al. now show that this is not the case. These mice had modifications to their muscle stem cells that allowed the number of these cells to be artificially reduced, and some cells also produced a fluorescent protein that allowed them to be tracked. Surgically severing some of the muscle-nerve connections in the mice triggered the rebuilding of the connections, but also weakened the muscles and caused some disease-related changes in the muscle tissue. During the healing process, the muscle stem cells are active near the regenerating connections. Reducing the number of muscle stem cells in the mice while these broken connections were healing further weakened the muscles. Closer inspection of the muscle-nerve connections also revealed poorer quality connections were formed in the stem-cell deficient mice. Further study of how stem cells help to form strong nerve-muscle connections may allow scientists to develop new treatments for age- or disease-related muscle loss. DOI:http://dx.doi.org/10.7554/eLife.09221.002
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Affiliation(s)
- Wenxuan Liu
- Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, United States
| | - Lan Wei-LaPierre
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, United States
| | - Alanna Klose
- Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, United States
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, United States
| | - Joe V Chakkalakal
- Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, United States
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144
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Tintignac LA, Brenner HR, Rüegg MA. Mechanisms Regulating Neuromuscular Junction Development and Function and Causes of Muscle Wasting. Physiol Rev 2015; 95:809-52. [DOI: 10.1152/physrev.00033.2014] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The neuromuscular junction is the chemical synapse between motor neurons and skeletal muscle fibers. It is designed to reliably convert the action potential from the presynaptic motor neuron into the contraction of the postsynaptic muscle fiber. Diseases that affect the neuromuscular junction may cause failure of this conversion and result in loss of ambulation and respiration. The loss of motor input also causes muscle wasting as muscle mass is constantly adapted to contractile needs by the balancing of protein synthesis and protein degradation. Finally, neuromuscular activity and muscle mass have a major impact on metabolic properties of the organisms. This review discusses the mechanisms involved in the development and maintenance of the neuromuscular junction, the consequences of and the mechanisms involved in its dysfunction, and its role in maintaining muscle mass during aging. As life expectancy is increasing, loss of muscle mass during aging, called sarcopenia, has emerged as a field of high medical need. Interestingly, aging is also accompanied by structural changes at the neuromuscular junction, suggesting that the mechanisms involved in neuromuscular junction maintenance might be disturbed during aging. In addition, there is now evidence that behavioral paradigms and signaling pathways that are involved in longevity also affect neuromuscular junction stability and sarcopenia.
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Affiliation(s)
- Lionel A. Tintignac
- Biozentrum, University of Basel, Basel, Switzerland; Department of Biomedicine, University of Basel, Basel, Switzerland; and INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Hans-Rudolf Brenner
- Biozentrum, University of Basel, Basel, Switzerland; Department of Biomedicine, University of Basel, Basel, Switzerland; and INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Markus A. Rüegg
- Biozentrum, University of Basel, Basel, Switzerland; Department of Biomedicine, University of Basel, Basel, Switzerland; and INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
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145
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Layec G, Trinity JD, Hart CR, Kim SE, Groot HJ, Le Fur Y, Sorensen JR, Jeong EK, Richardson RS. Impact of age on exercise-induced ATP supply during supramaximal plantar flexion in humans. Am J Physiol Regul Integr Comp Physiol 2015; 309:R378-88. [PMID: 26041112 DOI: 10.1152/ajpregu.00522.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 06/02/2015] [Indexed: 11/22/2022]
Abstract
Currently, the physiological factors responsible for exercise intolerance and bioenergetic alterations with age are poorly understood due, at least in art, to the confounding effect of reduced physical activity in the elderly. Thus, in 40 healthy young (22 ± 2 yr) and old (74 ± 8 yr) activity-matched subjects, we assessed the impact of age on: 1) the relative contribution of the three major pathways of ATP synthesis (oxidative ATP synthesis, glycolysis, and the creatine kinase reaction) and 2) the ATP cost of contraction during high-intensity exercise. Specifically, during supramaximal plantar flexion (120% of maximal aerobic power), to stress the functional limits of the skeletal muscle energy systems, we used (31)P-labeled magnetic resonance spectroscopy to assess metabolism. Although glycolytic activation was delayed in the old, ATP synthesis from the main energy pathways was not significantly different between groups. Similarly, the inferred peak rate of mitochondrial ATP synthesis was not significantly different between the young (25 ± 8 mM/min) and old (24 ± 6 mM/min). In contrast, the ATP cost of contraction was significantly elevated in the old compared with the young (5.1 ± 2.0 and 3.7 ± 1.7 mM·min(-1)·W(-1), respectively; P < 0.05). Overall, these findings suggest that, when young and old subjects are activity matched, there is no evidence of age-related mitochondrial and glycolytic dysfunction. However, this study does confirm an abnormal elevation in exercise-induced skeletal muscle metabolic demand in the old that may contribute to the decline in exercise capacity with advancing age.
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Affiliation(s)
- Gwenael Layec
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah;
| | - Joel D Trinity
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Corey R Hart
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Seong-Eun Kim
- Department of Radiology and Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah; and
| | - H Jonathan Groot
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Yann Le Fur
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, Marseille, France
| | - Jacob R Sorensen
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Eun-Kee Jeong
- Department of Radiology and Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah; and
| | - Russell S Richardson
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
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146
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Greising SM, Medina-Martínez JS, Vasdev AK, Sieck GC, Mantilla CB. Analysis of muscle fiber clustering in the diaphragm muscle of sarcopenic mice. Muscle Nerve 2015; 52:76-82. [PMID: 25808550 DOI: 10.1002/mus.24641] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2015] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Sarcopenia likely comprises muscle fiber denervation and re-innervation, resulting in clustering of muscle fibers of the same type (classified by myosin heavy chain isoform composition). Development of methodology to quantitatively evaluate clustering of muscle fibers according to fiber type is necessary. METHODS Fiber type specific immunofluorescence histology was used to quantify fiber clustering in murine diaphragm muscle (n = 15) at ages 6 and 24 months. RESULTS With age, fiber type clustering is evidenced by fiber type specific changes in distances between fibers, specifically a 14% decrease to the closest fiber for type I and 24% increase for type IIx and/or IIb fibers (P < 0.001). Additionally, a 34% increase to the 3 closest type IIx and/or IIb fibers was found (P < 0.001). CONCLUSIONS This novel method of analyzing fiber type clustering may be useful in examining pathophysiological conditions of motor unit loss in neuromuscular disorders, myopathies, dystrophies, injuries, or amyotrophic lateral sclerosis.
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Affiliation(s)
- Sarah M Greising
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, SMH Jo 4-184, Rochester, Minnesota, 55905, USA
| | - Juan S Medina-Martínez
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, SMH Jo 4-184, Rochester, Minnesota, 55905, USA
| | - Amrit K Vasdev
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, SMH Jo 4-184, Rochester, Minnesota, 55905, USA
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, SMH Jo 4-184, Rochester, Minnesota, 55905, USA.,Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, SMH Jo 4-184, Rochester, Minnesota, 55905, USA.,Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, USA
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147
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Lal N, Sheard P. Dying myofibers in elderly mouse skeletal muscles are characterized by the appearance of dystrophin-encircled vacuoles. Biogerontology 2015; 16:443-59. [DOI: 10.1007/s10522-015-9565-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 03/02/2015] [Indexed: 12/14/2022]
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148
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Frank AW, Farthing JP, Chilibeck PD, Arnold CM, Olszynski WP, Kontulainen SA. Community-dwelling female fallers have lower muscle density in their lower legs than non-fallers: evidence from the Saskatoon Canadian Multicentre Osteoporosis Study (CaMos) cohort. J Nutr Health Aging 2015; 19:113-20. [PMID: 25560824 DOI: 10.1007/s12603-014-0476-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVES Our objectives were to determine whether peripheral quantitative computed tomography (pQCT)-derived lower leg muscle density and area, and basic functional mobility differ between community-dwelling older women who do and do not report recent falls. DESIGN Matched case-control comparison. SETTING Academic biomedical imaging laboratory. PARTICIPANTS 147 Women, 60 years or older (mean age 74.3 y, SD 7.7) recruited from a longitudinal, population-based cohort representing community-dwelling residents in the area of Saskatoon, Canada. MEASUREMENTS A cross-sectional pQCT scan of the non-dominant lower leg was acquired to determine muscle density and area. Basic functional mobility (Timed Up and Go Test [TUG]) and SF36 health status were also measured. Fallers (one or more falls) and non-fallers (no falls) were grouped according to a 12-month retrospective survey and matched on measured covariates. RESULTS The muscle density of fallers (n = 35) was a median of 2.1 mg/cm3 lower (P = 0.019, 95% C.I. -3.9 to -0.1) than non-fallers (n = 78) after matching and adjusting for age, body mass index, and SF36 general health scores. Muscle area and TUG did not differ between fallers and non-fallers. CONCLUSIONS Muscle density may serve as a physiological marker in the assessment of lower leg muscular health and fall risk in community-dwelling elderly women. These results are limited to our study population who were mostly Caucasian. Prospective studies are required for verification.
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Affiliation(s)
- A W Frank
- A.W. Frank, M.Sc., College of Kinesiology, University of Saskatchewan, 87 Campus Drive, Saskatoon, SK. S7N5B2, Canada, Phone: +1 (306) 966-1123, Fax: +1 (306) 966-6464, E-mail:
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149
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Fiber type composition of the human quadratus plantae muscle: a comparison of the lateral and medial heads. J Foot Ankle Res 2014; 7:54. [PMID: 25530807 PMCID: PMC4271414 DOI: 10.1186/s13047-014-0054-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 11/27/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The human quadratus plantae muscle has been attributed a variety of functions, however no consensus has been reached on its significance to foot functioning. The architecture of the human quadratus plantae consists of an evolutionarily conserved lateral head, and a medial head thought to be unique to Man. Surveys of human anatomy have demonstrated the absence of either the medial or lateral head in 20% of the population, which may have implications for foot functioning if each muscle head performs a discrete function. METHODS We investigated the quadratus plantae from eleven formalin-embalmed specimens with a mean age of 84 ± 9 years. Immunohistochemical methods were used to determine the percentage of Type I and Type II muscle fibers in the medial and lateral heads of the quadratus plantae from these specimens. RESULTS Results showed striking homogeneity in fiber type composition within an individual, with an average difference in Type I fiber content of 4.1% between lateral and medial heads. Between individuals, however, the ratio of fiber types within the quadratus plantae was highly variable, with Type I fiber percentages ranging from 19.1% to 91.6% in the lateral head, and 20.4% to 97.0% within the medial head. CONCLUSIONS Our finding of similar fiber type composition of lateral and medial heads within an individual supports the hypothesis that the two heads have a singular function.
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Wu P, Chawla A, Spinner RJ, Yu C, Yaszemski MJ, Windebank AJ, Wang H. Key changes in denervated muscles and their impact on regeneration and reinnervation. Neural Regen Res 2014; 9:1796-809. [PMID: 25422641 PMCID: PMC4239769 DOI: 10.4103/1673-5374.143424] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2014] [Indexed: 11/29/2022] Open
Abstract
The neuromuscular junction becomes progressively less receptive to regenerating axons if nerve repair is delayed for a long period of time. It is difficult to ascertain the denervated muscle's residual receptivity by time alone. Other sensitive markers that closely correlate with the extent of denervation should be found. After a denervated muscle develops a fibrillation potential, muscle fiber conduction velocity, muscle fiber diameter, muscle wet weight, and maximal isometric force all decrease; remodeling increases neuromuscular junction fragmentation and plantar area, and expression of myogenesis-related genes is initially up-regulated and then down-regulated. All these changes correlate with both the time course and degree of denervation. The nature and time course of these denervation changes in muscle are reviewed from the literature to explore their roles in assessing both the degree of detrimental changes and the potential success of a nerve repair. Fibrillation potential amplitude, muscle fiber conduction velocity, muscle fiber diameter, mRNA expression levels of myogenic regulatory factors and nicotinic acetylcholine receptor could all reflect the severity and length of denervation and the receptiveness of denervated muscle to regenerating axons, which could possibly offer an important clue for surgical choices and predict the outcomes of delayed nerve repair.
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Affiliation(s)
- Peng Wu
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA ; Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, China ; Department of Orthopedic Surgery, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China
| | - Aditya Chawla
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA ; Department of Orthopedic Surgery, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Robert J Spinner
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Cong Yu
- Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Michael J Yaszemski
- Departments of Orthopedic Surgery and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | | | - Huan Wang
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA ; Shanghai Key Laboratory of Peripheral Nerve and Microsurgery, Shanghai, China
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