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Schirinzi E, Ricci G, Torri F, Mancuso M, Siciliano G. Biomolecules of Muscle Fatigue in Metabolic Myopathies. Biomolecules 2023; 14:50. [PMID: 38254650 PMCID: PMC10812926 DOI: 10.3390/biom14010050] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 12/20/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024] Open
Abstract
Metabolic myopathies are a group of genetic disorders that affect the normal functioning of muscles due to abnormalities in metabolic pathways. These conditions result in impaired energy production and utilization within muscle cells, leading to limitations in muscle function with concomitant occurrence of related signs and symptoms, among which fatigue is one of the most frequently reported. Understanding the underlying molecular mechanisms of muscle fatigue in these conditions is challenging for the development of an effective diagnostic and prognostic approach to test targeted therapeutic interventions. This paper outlines the key biomolecules involved in muscle fatigue in metabolic myopathies, including energy substrates, enzymes, ion channels, and signaling molecules. Potential future research directions in this field are also discussed.
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Machamer JB, Vazquez-Cintron EJ, Stenslik MJ, Pagarigan KT, Bradford AB, Ondeck CA, McNutt PM. Neuromuscular recovery from botulism involves multiple forms of compensatory plasticity. Front Cell Neurosci 2023; 17:1226194. [PMID: 37650071 PMCID: PMC10463753 DOI: 10.3389/fncel.2023.1226194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 07/28/2023] [Indexed: 09/01/2023] Open
Abstract
Introduction Botulinum neurotoxin (BoNT) causes neuroparalytic disease and death by blocking neuromuscular transmission. There are no specific therapies for clinical botulism and the only treatment option is supportive care until neuromuscular function spontaneously recovers, which can take weeks or months after exposure. The highly specialized neuromuscular junction (NMJ) between phrenic motor neurons and diaphragm muscle fibers is the main clinical target of BoNT. Due to the difficulty in eliciting respiratory paralysis without a high mortality rate, few studies have characterized the neurophysiological mechanisms involved in diaphragm recovery from intoxication. Here, we develop a mouse model of botulism that involves partial paralysis of respiratory muscles with low mortality rates, allowing for longitudinal analysis of recovery. Methods and results Mice challenged by systemic administration of 0.7 LD50 BoNT/A developed physiological signs of botulism, such as respiratory depression and reduced voluntary running activity, that persisted for an average of 8-12 d. Studies in isolated hemidiaphragm preparations from intoxicated mice revealed profound reductions in nerve-elicited, tetanic and twitch muscle contraction strengths that recovered to baseline 21 d after intoxication. Despite apparent functional recovery, neurophysiological parameters remained depressed for 28 d, including end plate potential (EPP) amplitude, EPP success rate, quantal content (QC), and miniature EPP (mEPP) frequency. However, QC recovered more quickly than mEPP frequency, which could explain the discrepancy between muscle function studies and neurophysiological recordings. Hypothesizing that differential modulation of voltage-gated calcium channels (VGCC) contributed to the uncoupling of QC from mEPP frequency, pharmacological inhibition studies were used to study the contributions of different VGCCs to neurophysiological function. We found that N-type VGCC and P/Q-type VGCC partially restored QC but not mEPP frequency during recovery from paralysis, potentially explaining the accelerated recovery of evoked release versus spontaneous release. We identified additional changes that presumably compensate for reduced acetylcholine release during recovery, including increased depolarization of muscle fiber resting membrane potential and increased quantal size. Discussion In addition to identifying multiple forms of compensatory plasticity that occur in response to reduced NMJ function, it is expected that insights into the molecular mechanisms involved in recovery from neuromuscular paralysis will support new host-targeted treatments for multiple neuromuscular diseases.
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Affiliation(s)
- James B. Machamer
- BASF, Research Triangle Park, NC, United States
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | | | - Mallory J. Stenslik
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | - Kathleen T. Pagarigan
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | - Aaron B. Bradford
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
| | - Celinia A. Ondeck
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Patrick M. McNutt
- United States Army Medical Research Institute of Chemical Defense, Gunpowder, MD, United States
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
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Supruniuk E, Górski J, Chabowski A. Endogenous and Exogenous Antioxidants in Skeletal Muscle Fatigue Development during Exercise. Antioxidants (Basel) 2023; 12:antiox12020501. [PMID: 36830059 PMCID: PMC9952836 DOI: 10.3390/antiox12020501] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/09/2023] [Accepted: 02/15/2023] [Indexed: 02/18/2023] Open
Abstract
Muscle fatigue is defined as a decrease in maximal force or power generated in response to contractile activity, and it is a risk factor for the development of musculoskeletal injuries. One of the many stressors imposed on skeletal muscle through exercise is the increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), which intensifies as a function of exercise intensity and duration. Exposure to ROS/RNS can affect Na+/K+-ATPase activity, intramyofibrillar calcium turnover and sensitivity, and actin-myosin kinetics to reduce muscle force production. On the other hand, low ROS/RNS concentrations can likely upregulate an array of cellular adaptative responses related to mitochondrial biogenesis, glucose transport and muscle hypertrophy. Consequently, growing evidence suggests that exogenous antioxidant supplementation might hamper exercise-engendering upregulation in the signaling pathways of mitogen-activated protein kinases (MAPKs), peroxisome-proliferator activated co-activator 1α (PGC-1α), or mammalian target of rapamycin (mTOR). Ultimately, both high (exercise-induced) and low (antioxidant intervention) ROS concentrations can trigger beneficial responses as long as they do not override the threshold range for redox balance. The mechanisms underlying the two faces of ROS/RNS in exercise, as well as the role of antioxidants in muscle fatigue, are presented in detail in this review.
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Affiliation(s)
- Elżbieta Supruniuk
- Department of Physiology, Medical University of Białystok, 15-222 Białystok, Poland
- Correspondence: ; Tel.: +48-(85)-748-55-85
| | - Jan Górski
- Department of Medical Sciences, Academy of Applied Sciences, 18-400 Łomża, Poland
| | - Adrian Chabowski
- Department of Physiology, Medical University of Białystok, 15-222 Białystok, Poland
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Luu MJ, Jones KE, Collins DF. Decreased excitability of motor axons contributes substantially to contraction fatigability during neuromuscular electrical stimulation. Appl Physiol Nutr Metab 2021; 46:346-355. [DOI: 10.1139/apnm-2020-0366] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The present study was designed to (i) determine the time course of changes in motor axon excitability during and after neuromuscular electrical stimulation (NMES); and (ii) characterize the relationship between contraction fatigability, NMES frequency, and changes at the axon, neuromuscular junction, and muscle. Eight neurologically intact participants attended 3 sessions. NMES was delivered over the common peroneal nerve at 20, 40, or 60 Hz for 8 min (0.3 s “on”, 0.7 s “off”). Threshold tracking was used to measure changes in axonal excitability. Supramaximal stimuli were used to assess neuromuscular transmission and force-generating capacity of the tibialis anterior muscle. Torque decreased by 49% and 62% during 8 min of 40 and 60 Hz NMES, respectively. Maximal twitch torque decreased only during 60 Hz NMES. Motor axon excitability decreased by 14%, 27%, and 35% during 20, 40, and 60 Hz NMES, respectively. Excitability recovered to baseline immediately (20 Hz) and at 2 min (40 Hz) and 4 min (60 Hz) following NMES. Overall, decreases in axonal excitability best predicted how torque declined over 8 min of NMES. During NMES, motor axons become less excitable and motor units “drop out” of the contraction, contributing substantially to contraction fatigability and its dependence on NMES frequency. Novelty: The excitability of motor axons decreased during NMES in a frequency-dependent manner. As excitability decreased, axons failed to reach threshold and motor units dropped out of the contraction. Overall, decreased excitability best predicted how torque declined and thus is a key contributor to fatigability during NMES.
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Affiliation(s)
- M. John Luu
- Faculty of Kinesiology, Sport, and Recreation, Neuroscience and Mental Health Institute, Sensorimotor Rehabilitation Neuroscience Group, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Kinesiology, Sport, and Recreation, Neuroscience and Mental Health Institute, Sensorimotor Rehabilitation Neuroscience Group, University of Alberta, Edmonton, AB T6G 2H9, Canada
| | - Kelvin E. Jones
- Faculty of Kinesiology, Sport, and Recreation, Neuroscience and Mental Health Institute, Sensorimotor Rehabilitation Neuroscience Group, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Kinesiology, Sport, and Recreation, Neuroscience and Mental Health Institute, Sensorimotor Rehabilitation Neuroscience Group, University of Alberta, Edmonton, AB T6G 2H9, Canada
| | - David F. Collins
- Faculty of Kinesiology, Sport, and Recreation, Neuroscience and Mental Health Institute, Sensorimotor Rehabilitation Neuroscience Group, University of Alberta, Edmonton, AB T6G 2H9, Canada
- Faculty of Kinesiology, Sport, and Recreation, Neuroscience and Mental Health Institute, Sensorimotor Rehabilitation Neuroscience Group, University of Alberta, Edmonton, AB T6G 2H9, Canada
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Acute and chronic neuromuscular electrical stimulation and postural balance: a review. Eur J Appl Physiol 2020; 120:1475-1488. [DOI: 10.1007/s00421-020-04383-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 04/23/2020] [Indexed: 01/12/2023]
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Arjunan SP, Siddiqi A, Swaminathan R, Kumar DK. Implementation and experimental validation of surface electromyogram and force model of Tibialis Anterior muscle for examining muscular factors. Proc Inst Mech Eng H 2020; 234:200-209. [DOI: 10.1177/0954411919890150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study reports a surface electromyogram and force of contraction model. The objective was to investigate the effect of changes in the size, type and number of motor units in the Tibialis Anterior muscle to surface electromyogram and force of dorsiflexion. A computational model to simulate surface electromyogram and associated force of contraction by the Tibialis Anterior muscle was developed. This model was simulated for isometric dorsiflexion, and comparative experiments were conducted for validation. Repeated simulations were performed to investigate the different parameters and evaluate inter-experimental variability. An equivalence statistical test and the Bland–Altman method were used to observe the significance between the simulated and experimental data. Simulated and experimentally recorded data had high similarity for the three measures: maximal power of power spectral density ( p < 0.0001), root mean square of surface electromyogram ( p < 0.0001) and force recorded at the footplate ( p < 0.03). Inter-subject variability in the experimental results was in-line with the variability in the repeated simulation results. This experimentally validated computational model for the surface electromyogram and force of the Tibialis Anterior muscle is significant as it allows the examination of three important muscular factors associated with ageing and disease: size, fibre type and number of motor units.
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Affiliation(s)
| | - Ariba Siddiqi
- Biosignals Lab, School of Engineering, RMIT University, Melbourne, VIC, Australia
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Waldron M, Patterson SD, Jeffries O. Oral taurine improves critical power and severe-intensity exercise tolerance. Amino Acids 2019; 51:1433-1441. [PMID: 31482309 DOI: 10.1007/s00726-019-02775-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 08/18/2019] [Indexed: 11/26/2022]
Abstract
This study investigated the effects of acute oral taurine ingestion on: (1) the power-time relationship using the 3-min all-out test (3MAOT); (2) time to exhaustion (TTE) 5% > critical power (CP) and (3) the estimated time to complete (Tlim) a range of fixed target intensities. Twelve males completed a baseline 3MAOT test on a cycle ergometer. Following this, a double-blind, randomised cross-over design was followed, where participants were allocated to one of four conditions, separated by 72 h: TTE + taurine; TTE + placebo; 3MAOT + taurine; 3MAOT + placebo. Taurine was provided at 50 mg kg-1, whilst the placebo was 3 mg kg-1 maltodextrin. CP was higher (P < 0.05) in taurine (212 ± 36 W) than baseline (197 ± 40 W) and placebo (193 ± 35 W). Work end power was not affected by supplement (P > 0.05), yet TTE 5% > CP increased (P < 0.05) by 1.7 min after taurine (17.7 min) compared to placebo (16.0 min) and there were higher (P < 0.001) estimated Tlim across all work targets. Acute supplementation of 50 mg kg-1 of taurine improved CP and estimated performance at a range of severe work intensities. Oral taurine can be taken prior to exercise to enhance endurance performance.
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Affiliation(s)
- Mark Waldron
- College of Engineering, Swansea University, Swansea, SA1 8EN, UK.
- School of Science and Technology, University of New England, Armidale, NSW, Australia.
| | | | - Owen Jeffries
- School of Biomedical Sciences, Newcastle University, Newcastle upon Tyne, UK
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Voluntary and electrically-induced muscle fatigue differently affect postural control mechanisms in unipedal stance. Exp Brain Res 2018; 237:313-323. [DOI: 10.1007/s00221-018-5418-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 10/25/2018] [Indexed: 12/12/2022]
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Semplicini C, Hézode-Arzel M, Laforêt P, Béhin A, Leonard-Louis S, Hogrel JY, Petit F, Eymard B, Stojkovic T, Fournier E. The role of electrodiagnosis with long exercise test in mcardle disease. Muscle Nerve 2018; 58:64-71. [PMID: 29350794 DOI: 10.1002/mus.26074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 01/11/2018] [Accepted: 01/13/2018] [Indexed: 11/07/2022]
Abstract
INTRODUCTION In this study we evaluated the role of an electrodiagnostic provocative test (long exercise test) in McArdle disease. METHODS Twenty-five McArdle patients and 2 control groups underwent an electrodiagnostic protocol with long exercise test (LET), consisting of recording the compound muscle action potential (CMAP) before and after 5 minutes of isometric contraction. RESULTS The LET disclosed a postexercise decrease in CMAP amplitude in 23 of 25 McArdle patients. The immediate and long-lasting decrease differentiated McArdle patients from controls. Patients with a normal LET demonstrated milder symptoms and/or residual myophosphorylase activity. DISCUSSION The LET is a sensitive, safe, and noninvasive provocative test that may guide clinicians toward molecular analysis of the myophosphorylase gene. The abnormalities observed on LET point toward complex biochemical mechanisms determined by the absence of myophosphorylase, beyond simple glycolytic blockade (ionic pump dysfunction, sarcolemmal inexcitability). The normal LET in patients with milder symptoms indicates a relationship of the LET with clinical severity, thus identifying it as a potential outcome measure. Muscle Nerve, 2018.
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Affiliation(s)
- Claudio Semplicini
- Department of Neuroscience, University of Padova, Padova, Italy
- Paris-Est Neuromuscular Center, APHP-GH Pitié-Salpêtrière, Paris, France
| | | | - Pascal Laforêt
- Centre de référence des maladies neuromusculaires Nord/Est/Ile de France Service de Neurologie, Hôpital Raymond-Poincaré, AP-HP, Garches INSERM U1179, END-ICAP, équipe biothérapies des maladies du système neuromusculaire Université Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France
| | - Anthony Béhin
- Paris-Est Neuromuscular Center, APHP-GH Pitié-Salpêtrière, Paris, France
| | | | - Jean-Yves Hogrel
- Neuromuscular Physiology Laboratory, Institut de Myologie, APHP-GH Pitié-Salpêtrière, Paris, France
| | - François Petit
- Molecular Genetics; Metabolic Diseases Lab, Antoine Béclère Hospital, Clamart, France
| | - Bruno Eymard
- Paris-Est Neuromuscular Center, APHP-GH Pitié-Salpêtrière, Paris, France
| | - Tanya Stojkovic
- Paris-Est Neuromuscular Center, APHP-GH Pitié-Salpêtrière, Paris, France
| | - Emmanuel Fournier
- Department of Clinical Neurophysiology, APHP-GH Pitié-Salpêtrière, Paris, France
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Behringer M, Grützner S, Montag J, McCourt M, Ring M, Mester J. Effects of stimulation frequency, amplitude, and impulse width on muscle fatigue. Muscle Nerve 2015; 53:608-16. [PMID: 26335028 DOI: 10.1002/mus.24893] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 11/10/2022]
Abstract
INTRODUCTION We investigated the effect of stimulation intensity (in percent of maximal tolerated stimulation current, mTSC), frequency, and impulse width on muscle fatigue. METHODS Using a randomized crossover design, 6 parameter combinations (80% mTSC, 80 Hz, 400 μs; 60% mTSC, 80 Hz, 400 μs; 80% mTSC, 20 Hz, 400 μs; 60% mTSC, 20 Hz, 400 μs; 80% mTSC, 80 Hz, 150 μs; 60% mTSC, 80 Hz, 150 μs) were tested in both legs of 13 athletic men (age 26 ± 2.3). The slope of the linear regression line over all tetani (FIS) and the number of tetani whose force was above 50% of the initial tetanus (FIN) were used to quantify fatigue. RESULTS FIS and FIN were significantly lower in high-frequency protocols. No effects on FIS and FIN were found for intensity and impulse width. CONCLUSIONS Stimulation frequency, but not impulse width or intensity, affected fatigue kinetics.
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Affiliation(s)
- Michael Behringer
- Institute for Training Science and Sport Informatics, German Sport University Cologne, Am Sportpark Müngersdorf, 50933, Cologne, Germany
| | - Sebastian Grützner
- Institute for Training Science and Sport Informatics, German Sport University Cologne, Am Sportpark Müngersdorf, 50933, Cologne, Germany
| | - Johannes Montag
- Institute for Training Science and Sport Informatics, German Sport University Cologne, Am Sportpark Müngersdorf, 50933, Cologne, Germany
| | - Molly McCourt
- Institute for Training Science and Sport Informatics, German Sport University Cologne, Am Sportpark Müngersdorf, 50933, Cologne, Germany
| | - Matthias Ring
- Digital Sports Group, Pattern Recognition Lab, Friedrich-Alexander University Erlangen-Nuremberg, Germany
| | - Joachim Mester
- Institute for Training Science and Sport Informatics, German Sport University Cologne, Am Sportpark Müngersdorf, 50933, Cologne, Germany
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Cozzoli A, Liantonio A, Conte E, Cannone M, Massari AM, Giustino A, Scaramuzzi A, Pierno S, Mantuano P, Capogrosso RF, Camerino GM, De Luca A. Angiotensin II modulates mouse skeletal muscle resting conductance to chloride and potassium ions and calcium homeostasis via the AT1 receptor and NADPH oxidase. Am J Physiol Cell Physiol 2014; 307:C634-47. [PMID: 25080489 DOI: 10.1152/ajpcell.00372.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Angiotensin II (ANG II) plays a role in muscle wasting and remodeling; however, little evidence shows its direct effects on specific muscle functions. We presently investigated the acute in vitro effects of ANG II on resting ionic conductance and calcium homeostasis of mouse extensor digitorum longus (EDL) muscle fibers, based on previous findings that in vivo inhibition of ANG II counteracts the impairment of macroscopic ClC-1 chloride channel conductance (gCl) in the mdx mouse model of muscular dystrophy. By means of intracellular microelectrode recordings we found that ANG II reduced gCl in the nanomolar range and in a concentration-dependent manner (EC50 = 0.06 μM) meanwhile increasing potassium conductance (gK). Both effects were inhibited by the ANG II receptors type 1 (AT1)-receptor antagonist losartan and the protein kinase C inhibitor chelerythrine; no antagonism was observed with the AT2 antagonist PD123,319. The scavenger of reactive oxygen species (ROS) N-acetyl cysteine and the NADPH-oxidase (NOX) inhibitor apocynin also antagonized ANG II effects on resting ionic conductances; the ANG II-dependent gK increase was blocked by iberiotoxin, an inhibitor of calcium-activated potassium channels. ANG II also lowered the threshold for myofiber and muscle contraction. Both ANG II and the AT1 agonist L162,313 increased the intracellular calcium transients, measured by fura-2, with a two-step pattern. These latter effects were not observed in the presence of losartan and of the phospholipase C inhibitor U73122 and the in absence of extracellular calcium, disclosing a Gq-mediated calcium entry mechanism. The data show for the first time that the AT1-mediated ANG II pathway, also involving NOX and ROS, directly modulates ion channels and calcium homeostasis in adult myofibers.
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Affiliation(s)
- Anna Cozzoli
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | - Antonella Liantonio
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | - Elena Conte
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | - Maria Cannone
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | - Ada Maria Massari
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | - Arcangela Giustino
- Department of Biomedical Sciences and Human Oncology, University of Bari "A. Moro," Bari, Italy
| | - Antonia Scaramuzzi
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | - Sabata Pierno
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | - Paola Mantuano
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | | | - Giulia Maria Camerino
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
| | - Annamaria De Luca
- Unit of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "A. Moro," Bari, Italy; and
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Petrie MA, Suneja M, Faidley E, Shields RK. Low force contractions induce fatigue consistent with muscle mRNA expression in people with spinal cord injury. Physiol Rep 2014; 2:e00248. [PMID: 24744911 PMCID: PMC3966256 DOI: 10.1002/phy2.248] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 01/30/2014] [Accepted: 01/31/2014] [Indexed: 11/11/2022] Open
Abstract
Spinal cord injury (SCI) is associated with muscle atrophy, transformation of muscle fibers to a fast fatigable phenotype, metabolic inflexibility (diabetes), and neurogenic osteoporosis. Electrical stimulation of paralyzed muscle may mitigate muscle metabolic abnormalities after SCI, but there is a risk for a fracture to the osteoporotic skeletal system. The goal of this study was to determine if low force stimulation (3 Hz) causes fatigue of chronically paralyzed muscle consistent with selected muscle gene expression profiles. We tested 29 subjects, nine with a SCI and 20 without and SCI, during low force fatigue protocol. Three SCI and three non-SCI subjects were muscle biopsied for gene and protein expression analysis. The fatigue index (FI) was 0.21 ± 0.27 and 0.91 ± 0.01 for the SCI and non-SCI groups, respectively, supporting that the low force protocol physiologically fatigued the chronically paralyzed muscle. The post fatigue potentiation index (PI) for the SCI group was increased to 1.60 ± 0.06 (P <0.001), while the non-SCI group was 1.26 ± 0.02 supporting that calcium handling was compromised with the low force stimulation. The mRNA expression from genes that regulate atrophy and fast properties (MSTN, ANKRD1, MYH8, and MYCBP2) was up regulated, while genes that regulate oxidative and slow muscle properties (MYL3, SDHB, PDK2, and RyR1) were repressed in the chronic SCI muscle. MSTN, ANKRD1, MYH8, MYCBP2 gene expression was also repressed 3 h after the low force stimulation protocol. Taken together, these findings support that a low force single twitch activation protocol induces paralyzed muscle fatigue and subsequent gene regulation. These findings suggest that training with a low force protocol may elicit skeletal muscle adaptations in people with SCI.
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Affiliation(s)
- Michael A Petrie
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Manish Suneja
- Department of Internal Medicine, Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Elizabeth Faidley
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Richard K Shields
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, The University of Iowa, Iowa City, Iowa ; Department of Veterans Affairs, VA Medical Center, Iowa City, Iowa
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