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Pendleton EG, Nichenko AS, Mcfaline-Figueroa J, Raymond-Pope CJ, Schifino AG, Pigg TM, Barrow RP, Greising SM, Call JA, Mortensen LJ. Compromised Muscle Properties in a Severe Hypophosphatasia Murine Model. Int J Mol Sci 2023; 24:15905. [PMID: 37958888 PMCID: PMC10649932 DOI: 10.3390/ijms242115905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
Hypophosphatasia (HPP) is a rare metabolic bone disorder characterized by low levels of tissue non-specific alkaline phosphatase (TNAP) that causes under-mineralization of the bone, leading to bone deformity and fractures. In addition, patients often present with chronic muscle pain, reduced muscle strength, and an altered gait. In this work, we explored dynamic muscle function in a homozygous TNAP knockout mouse model of severe juvenile onset HPP. We found a reduction in skeletal muscle size and impairment in a range of isolated muscle contractile properties. Using histological methods, we found that the structure of HPP muscles was similar to healthy muscles in fiber size, actin and myosin structures, as well as the α-tubulin and mitochondria networks. However, HPP mice had significantly fewer embryonic and type I fibers than wild type mice, and fewer metabolically active NADH+ muscle fibers. We then used oxygen respirometry to evaluate mitochondrial function and found that complex I and complex II leak respiration were reduced in HPP mice, but that there was no disruption in efficiency of electron transport in complex I or complex II. In summary, the severe HPP mouse model recapitulates the muscle strength impairment phenotypes observed in human patients. Further exploration of the role of alkaline phosphatase in skeletal muscle could provide insight into mechanisms of muscle weakness in HPP.
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Affiliation(s)
- Emily G. Pendleton
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
| | - Anna S. Nichenko
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
- Department of Physiology & Pharmacology, University of Georgia, Athens, GA 30602, USA
| | - Jennifer Mcfaline-Figueroa
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
- Department of Physiology & Pharmacology, University of Georgia, Athens, GA 30602, USA
| | | | - Albino G. Schifino
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
- Department of Physiology & Pharmacology, University of Georgia, Athens, GA 30602, USA
| | - Taylor M. Pigg
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
| | - Ruth P. Barrow
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
| | - Sarah M. Greising
- School of Kinesiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jarrod A. Call
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
- Department of Physiology & Pharmacology, University of Georgia, Athens, GA 30602, USA
| | - Luke J. Mortensen
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
- Department of Physiology & Pharmacology, University of Georgia, Athens, GA 30602, USA
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA
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Hahn D, Quick JD, Thompson BR, Crabtree A, Hackel BJ, Bates FS, Metzger JM. Rapid restitution of contractile dysfunction by synthetic copolymers in dystrophin-deficient single live skeletal muscle fibers. Skelet Muscle 2023; 13:9. [PMID: 37208786 PMCID: PMC10197332 DOI: 10.1186/s13395-023-00318-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 05/05/2023] [Indexed: 05/21/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is caused by the lack of dystrophin, a cytoskeletal protein essential for the preservation of the structural integrity of the muscle cell membrane. DMD patients develop severe skeletal muscle weakness, degeneration, and early death. We tested here amphiphilic synthetic membrane stabilizers in mdx skeletal muscle fibers (flexor digitorum brevis; FDB) to determine their effectiveness in restoring contractile function in dystrophin-deficient live skeletal muscle fibers. After isolating FDB fibers via enzymatic digestion and trituration from thirty-three adult male mice (9 C57BL10, 24 mdx), these were plated on a laminin-coated coverslip and treated with poloxamer 188 (P188; PEO75-PPO30-PEO75; 8400 g/mol), architecturally inverted triblock (PPO15-PEO200-PPO15, 10,700 g/mol), and diblock (PEO75-PPO16-C4, 4200 g/mol) copolymers. We assessed the twitch kinetics of sarcomere length (SL) and intracellular Ca2+ transient by Fura-2AM by field stimulation (25 V, 0.2 Hz, 25 °C). Twitch contraction peak SL shortening of mdx FDB fibers was markedly depressed to 30% of the dystrophin-replete control FDB fibers from C57BL10 (P < 0.001). Compared to vehicle-treated mdx FDB fibers, copolymer treatment robustly and rapidly restored the twitch peak SL shortening (all P < 0.05) by P188 (15 μM = + 110%, 150 μM = + 220%), diblock (15 μM = + 50%, 150 μM = + 50%), and inverted triblock copolymer (15 μM = + 180%, 150 μM = + 90%). Twitch peak Ca2+ transient from mdx FDB fibers was also depressed compared to C57BL10 FDB fibers (P < 0.001). P188 and inverted triblock copolymer treatment of mdx FDB fibers increased the twitch peak Ca2+ transient (P < 0.001). This study shows synthetic block copolymers with varied architectures can rapidly and highly effectively enhance contractile function in live dystrophin-deficient skeletal muscle fibers.
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Affiliation(s)
- Dongwoo Hahn
- Department of Integrative Biology & Physiology, Medical School, University of Minnesota, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Joseph D Quick
- Department of Integrative Biology & Physiology, Medical School, University of Minnesota, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Brian R Thompson
- Department of Integrative Biology & Physiology, Medical School, University of Minnesota, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Adelyn Crabtree
- Chemical Engineering & Materials Science, University of Minnesota, 151 Amundson Hall, 421 Washington Avenue SE, Minneapolis, MN, 55455, USA
| | - Benjamin J Hackel
- Chemical Engineering & Materials Science, University of Minnesota, 151 Amundson Hall, 421 Washington Avenue SE, Minneapolis, MN, 55455, USA
| | - Frank S Bates
- Chemical Engineering & Materials Science, University of Minnesota, 151 Amundson Hall, 421 Washington Avenue SE, Minneapolis, MN, 55455, USA
| | - Joseph M Metzger
- Department of Integrative Biology & Physiology, Medical School, University of Minnesota, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.
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Jakobsgaard JE, de Paoli F, Vissing K. Protein signaling in response to ex vivo dynamic contractions is independent of training status in rat skeletal muscle. Exp Physiol 2022; 107:919-932. [PMID: 35723680 PMCID: PMC9545705 DOI: 10.1113/ep090446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/16/2022] [Indexed: 11/24/2022]
Abstract
New Findings What is the central question of this study? Are myofibre protein signalling responses to ex vivo dynamic contractions altered by accustomization to voluntary endurance training in rats? What is the main finding and its importance? In response to ex vivo dynamic muscle contractions, canonical myofibre protein signalling pertaining to metabolic transcriptional regulation, as well as translation initiation and elongation, was not influenced by prior accustomization to voluntary endurance training in rats. Accordingly, intrinsic myofibre protein signalling responses to standardized contractile activity may be independent of prior exercise training in rat skeletal muscle.
Abstract Skeletal muscle training status may influence myofibre regulatory protein signalling in response to contractile activity. The current study employed a purpose‐designed ex vivo dynamic contractile protocol to evaluate the effect of exercise‐accustomization on canonical myofibre protein signalling for metabolic gene expression and for translation initiation and elongation. To this end, rats completed 8 weeks of in vivo voluntary running training versus no running control intervention, whereupon an ex vivo endurance‐type dynamic contraction stimulus was conducted in isolated soleus muscle preparations from both intervention groups. Protein signalling response by phosphorylation was evaluated by immunoblotting at 0 and 3 h following ex vivo stimulation. Phosphorylation of AMP‐activated protein kinase α‐isoforms and its downstream target, acetyl‐CoA carboxylase, as well as phosphorylation of eukaryotic elongation factor 2 (eEF2) was increased immediately following the dynamic contraction protocol (at 0 h). Signalling for translation initiation and elongation was evident at 3 h after dynamic contractile activity, as evidenced by increased phosphorylation of p70 S6 kinase and eukaryotic translation initiation factor 4E‐binding protein 1, as well as a decrease in phosphorylation of eEF2 back to resting control levels. However, prior exercise training did not alter phosphorylation responses of the investigated signalling proteins. Accordingly, protein signalling responses to standardized endurance‐type contractions may be independent of training status in rat muscle during ex vivo conditions. The present findings add to our current understanding of molecular regulatory events responsible for skeletal muscle plasticity.
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Affiliation(s)
- Jesper Emil Jakobsgaard
- Exercise Biology, Department of Public Health, Faculty of Health, Aarhus University, Denmark
| | - Frank de Paoli
- Department of Biomedicine, Faculty of Health, Aarhus University, Denmark
| | - Kristian Vissing
- Exercise Biology, Department of Public Health, Faculty of Health, Aarhus University, Denmark
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4
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Cairns SP, Leader JP, Higgins A, Renaud JM. The peak force - resting membrane potential relationships of mouse fast- and slow-twitch muscle. Am J Physiol Cell Physiol 2022; 322:C1151-C1165. [PMID: 35385328 DOI: 10.1152/ajpcell.00401.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We endeavored to understand the factors determining the peak force‑resting membrane potential (EM) relationships of isolated slow-twitch soleus and fast-twitch extensor digitorum longus (EDL) muscles from mice (25oC), especially in relation to fatigue. Inter-relationships between intracellular K+‑activity (aK+i), extracellular K+‑concentration ([K+]o), resting EM, action potentials and force were studied. The large resting EM variation was mainly due to the variability of aK+i. Action potential overshoot‑resting EM relationships determined at 4 and 8-10mM[K+]o following short (<5min) and prolonged (>50min) depolarization periods revealed a constant overshoot from ‑90 to ‑70mV providing a safety margin. Overshoot decline with depolarization beyond ‑70mV was less following short than prolonged depolarization. Inexcitable fibers occurred only with prolonged depolarization. The overshoot decline during action potential trains (2‑s) exceeded that during short depolarizations. Concomitant lower extracellular [Na+] and raised [K+]o depressed the overshoot in an additive manner and peak force in a synergistic manner. Raised [K+]o-induced force loss was exacerbated with transverse wire versus parallel plate stimulation in soleus, implicating action potential propagation failure in the surface membrane. Increasing stimulus pulse parameters restored tetanic force at 9‑10mM[K+]o in soleus, but not EDL, indicative of action potential failure within trains. The peak tetanic force‑resting EM relationships (determined using resting EM from deeper rather than surface fibers) were dynamic and show pronounced force depression over ‑69 to ‑60mV in both muscle-types, implicating that such depolarization contributes to fatigue. The K+-Na+-interaction shifted this relationship towards less depolarized potentials suggesting that the combined ionic effect is physiologically important during fatigue.
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Affiliation(s)
- Simeon P Cairns
- SPRINZ, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand.,Department of Physiology, School of Medicine, University of Auckland, Auckland, New Zealand
| | - John P Leader
- Department of Physiology, University of Otago, Dunedin, New Zealand.,Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Amanda Higgins
- Department of Cellular and Molecular Medicine, Neuromuscular Research Center, University of Ottawa, Ottawa, Canada
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Neuromuscular Research Center, University of Ottawa, Ottawa, Canada
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5
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Olesen JH, Herskind J, Pedersen KK, Overgaard K. Potassium-induced potentiation of subtetanic force in rat skeletal muscles: influences of β 2-activation, lactic acid, and temperature. Am J Physiol Cell Physiol 2021; 321:C884-C896. [PMID: 34613841 DOI: 10.1152/ajpcell.00120.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 09/28/2021] [Indexed: 02/04/2023]
Abstract
Moderate elevations of extracellular K+ concentration ([K+]o) occur during exercise and have been shown to potentiate force during contractions elicited with subtetanic frequencies. Here, we investigated whether lactic acid (reduced chloride conductance), β2-adrenoceptor activation, and increased temperature would influence the potentiating effect of potassium in slow- and fast-twitch muscles. Isometric contractions were elicited by electrical stimulation at various frequencies in isolated rat soleus and extensor digitorum longus (EDL) muscles incubated at normal (4 mM) or elevated K+, in combination with salbutamol (5 μM), lactic acid (18.1 mM), 9-anthracene-carboxylic acid (9-AC; 25 μM), or increased temperature (30-35°C). Elevating [K+]o from 4 mM to 7 mM (soleus) and 10 mM (EDL) potentiated isometric twitch and subtetanic force while slightly reducing tetanic force. In EDL, salbutamol further augmented twitch force (+27 ± 3%, P < 0.001) and subtetanic force (+22 ± 4%, P < 0.001). In contrast, salbutamol reduced subtetanic force (-28 ± 6%, P < 0.001) in soleus muscles. Lactic acid and 9-AC had no significant effects on isometric force of muscles already exposed to moderate elevations of [K+]o. The potentiating effect of elevated [K+]o was still well maintained at 35°C. Addition of salbutamol exerts a further force-potentiating effect in fast-twitch but not in slow-twitch muscles already potentiated by moderately elevated [K+]o, whereas lactic acid, 9-AC, or increased temperature does not exert any further augmentation. However, the potentiating effect of elevated [K+]o was still maintained in the presence of these, thus emphasizing the positive influence of moderately elevated [K+]o for contractile performance during exercise.
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Affiliation(s)
- Jonas H Olesen
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Jon Herskind
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Katja K Pedersen
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Kristian Overgaard
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
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6
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Matrigel 3D bioprinting of contractile human skeletal muscle models recapitulating exercise and pharmacological responses. Commun Biol 2021; 4:1183. [PMID: 34650188 PMCID: PMC8516940 DOI: 10.1038/s42003-021-02691-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 09/16/2021] [Indexed: 12/25/2022] Open
Abstract
A key to enhance the low translatability of preclinical drug discovery are in vitro human three-dimensional (3D) microphysiological systems (MPS). Here, we show a new method for automated engineering of 3D human skeletal muscle models in microplates and functional compound screening to address the lack of muscle wasting disease medication. To this end, we adapted our recently described 24-well plate 3D bioprinting platform with a printhead cooling system to allow microvalve-based drop-on-demand printing of cell-laden Matrigel containing primary human muscle precursor cells. Mini skeletal muscle models develop within a week exhibiting contractile, striated myofibers aligned between two attachment posts. As an in vitro exercise model, repeated high impact stimulation of contractions for 3 h by a custom-made electrical pulse stimulation (EPS) system for 24-well plates induced interleukin-6 myokine expression and Akt hypertrophy pathway activation. Furthermore, the known muscle stimulators caffeine and Tirasemtiv acutely increase EPS-induced contractile force of the models. This validated new human muscle MPS will benefit development of drugs against muscle wasting diseases. Moreover, our Matrigel 3D bioprinting platform will allow engineering of non-self-organizing complex human 3D MPS. Alave-Furrer et al adapted their recently-developed 3D bioprinting platform to allow microvalve-based drop-on-demand printing of cell-laden Matrigel containing primary human muscle precursor cells. Their bioprinting platform recapitulated aspects of exercise and pharmacological responses and thus could aid the engineering of more complex 3D microphysiological systems.
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7
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Mitochondria-localized AMPK responds to local energetics and contributes to exercise and energetic stress-induced mitophagy. Proc Natl Acad Sci U S A 2021; 118:2025932118. [PMID: 34493662 PMCID: PMC8449344 DOI: 10.1073/pnas.2025932118] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/05/2021] [Indexed: 12/25/2022] Open
Abstract
Mitochondria form a complex, interconnected reticulum that is maintained through coordination among biogenesis, dynamic fission, and fusion and mitophagy, which are initiated in response to various cues to maintain energetic homeostasis. These cellular events, which make up mitochondrial quality control, act with remarkable spatial precision, but what governs such spatial specificity is poorly understood. Herein, we demonstrate that specific isoforms of the cellular bioenergetic sensor, 5' AMP-activated protein kinase (AMPKα1/α2/β2/γ1), are localized on the outer mitochondrial membrane, referred to as mitoAMPK, in various tissues in mice and humans. Activation of mitoAMPK varies across the reticulum in response to energetic stress, and inhibition of mitoAMPK activity attenuates exercise-induced mitophagy in skeletal muscle in vivo. Discovery of a mitochondrial pool of AMPK and its local importance for mitochondrial quality control underscores the complexity of sensing cellular energetics in vivo that has implications for targeting mitochondrial energetics for disease treatment.
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8
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Hostrup M, Cairns SP, Bangsbo J. Muscle Ionic Shifts During Exercise: Implications for Fatigue and Exercise Performance. Compr Physiol 2021; 11:1895-1959. [PMID: 34190344 DOI: 10.1002/cphy.c190024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exercise causes major shifts in multiple ions (e.g., K+ , Na+ , H+ , lactate- , Ca2+ , and Cl- ) during muscle activity that contributes to development of muscle fatigue. Sarcolemmal processes can be impaired by the trans-sarcolemmal rundown of ion gradients for K+ , Na+ , and Ca2+ during fatiguing exercise, while changes in gradients for Cl- and Cl- conductance may exert either protective or detrimental effects on fatigue. Myocellular H+ accumulation may also contribute to fatigue development by lowering glycolytic rate and has been shown to act synergistically with inorganic phosphate (Pi) to compromise cross-bridge function. In addition, sarcoplasmic reticulum Ca2+ release function is severely affected by fatiguing exercise. Skeletal muscle has a multitude of ion transport systems that counter exercise-related ionic shifts of which the Na+ /K+ -ATPase is of major importance. Metabolic perturbations occurring during exercise can exacerbate trans-sarcolemmal ionic shifts, in particular for K+ and Cl- , respectively via metabolic regulation of the ATP-sensitive K+ channel (KATP ) and the chloride channel isoform 1 (ClC-1). Ion transport systems are highly adaptable to exercise training resulting in an enhanced ability to counter ionic disturbances to delay fatigue and improve exercise performance. In this article, we discuss (i) the ionic shifts occurring during exercise, (ii) the role of ion transport systems in skeletal muscle for ionic regulation, (iii) how ionic disturbances affect sarcolemmal processes and muscle fatigue, (iv) how metabolic perturbations exacerbate ionic shifts during exercise, and (v) how pharmacological manipulation and exercise training regulate ion transport systems to influence exercise performance in humans. © 2021 American Physiological Society. Compr Physiol 11:1895-1959, 2021.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Simeon Peter Cairns
- SPRINZ, School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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9
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Xu H, Liang T, Wei L, Zhu JC, Liu X, Ji CC, Liu B, Luo ZP. Nano-elastic modulus of tendon measured directly in living mice. J Biomech 2021; 116:110248. [PMID: 33485146 DOI: 10.1016/j.jbiomech.2021.110248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/23/2020] [Accepted: 01/03/2021] [Indexed: 01/16/2023]
Abstract
The nano-biomechanical environment of the extracellular matrix is critical for cells to sense and respond to mechanical loading. However, to date, this important characteristic remains poorly understood in living tissue structures. This study reports the experimental measurement of the in vivo nano-elastic modulus of the tendon in a mouse tail model. The experiment was performed on the tail tendon of an 8-week-old C57BL/6 live mouse. Mechanical loading on tail tendons was regulated by changing both voltage and frequency of alternating current stimulation on the erector spinae. The nano-elastic modulus of the tail tendon was measured by atomic force microscope. The nano-elastic modulus showed significant variation (2.19-35.70 MPa) between different locations and up to 39% decrease under muscle contraction, suggesting a complicated biomechanical environment in which cells dwell. In addition, the nano-elastic modulus of the tail tendon measured in live mice was significantly lower than that measured in vitro, suggesting a disagreement of tissue mechanical properties in vivo and in vitro. This information is important for the designs of new extracellular biomaterial that can better mimic the biological environment, and improve clinical outcomes of musculoskeletal tissue degenerations and associated disorders.
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Affiliation(s)
- Hao Xu
- Orthopedic Institute, Medical College, Soochow University, Suzhou, PR China; Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Ting Liang
- Orthopedic Institute, Medical College, Soochow University, Suzhou, PR China; Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Liangyi Wei
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Jun-Cheng Zhu
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Xuhui Liu
- San Francisco Veterans Affairs Health Care System, and Department of Orthopedic Surgery, University of California at San Francisco, 1700 Owens Street, Room 364, San Francisco, CA 94158, USA
| | - Chen-Chen Ji
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Bo Liu
- Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Zong-Ping Luo
- Orthopedic Institute, Medical College, Soochow University, Suzhou, PR China; Orthopaedic Institute, Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China.
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10
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Hoshino D, Kawata K, Kunida K, Hatano A, Yugi K, Wada T, Fujii M, Sano T, Ito Y, Furuichi Y, Manabe Y, Suzuki Y, Fujii NL, Soga T, Kuroda S. Trans-omic Analysis Reveals ROS-Dependent Pentose Phosphate Pathway Activation after High-Frequency Electrical Stimulation in C2C12 Myotubes. iScience 2020; 23:101558. [PMID: 33083727 PMCID: PMC7522805 DOI: 10.1016/j.isci.2020.101558] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/06/2020] [Accepted: 09/10/2020] [Indexed: 12/21/2022] Open
Abstract
Skeletal muscle adaptation is mediated by cooperative regulation of metabolism, signal transduction, and gene expression. However, the global regulatory mechanism remains unclear. To address this issue, we performed electrical pulse stimulation (EPS) in differentiated C2C12 myotubes at low and high frequency, carried out metabolome and transcriptome analyses, and investigated phosphorylation status of signaling molecules. EPS triggered extensive and specific changes in metabolites, signaling phosphorylation, and gene expression during and after EPS in a frequency-dependent manner. We constructed trans-omic network by integrating these data and found selective activation of the pentose phosphate pathway including metabolites, upstream signaling molecules, and gene expression of metabolic enzymes after high-frequency EPS. We experimentally validated that activation of these molecules after high-frequency EPS was dependent on reactive oxygen species (ROS). Thus, the trans-omic analysis revealed ROS-dependent activation in signal transduction, metabolome, and transcriptome after high-frequency EPS in C2C12 myotubes, shedding light on possible mechanisms of muscle adaptation. We performed electrical pulse stimulation in differentiated C2C12 myotubes We constructed trans-omic network after high-frequency electrical pulse stimulation Trans-omic network integrates metabolome, transcriptome, and signaling molecules We identified ROS-dependent pentose phosphate pathway activation
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Affiliation(s)
- Daisuke Hoshino
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Bioscience and Technology Program, Department of Engineering Science, University of Electro-Communications, Tokyo 182-8585, Japan
| | - Kentaro Kawata
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Katsuyuki Kunida
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Graduate School of Biological Sciences, and Data Science Center, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Atsushi Hatano
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Department of Omics and Systems Biology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Katsuyuki Yugi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Laboratory for Integrated Cellular Systems, RIKEN Center for Integrative Medical Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Institute for Advanced Biosciences, Keio University, Fujisawa, 252-8520, Japan
- PRESTO, Japan Science and Technology Agency, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Takumi Wada
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masashi Fujii
- Department of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-8526, Japan
| | - Takanori Sano
- Department of Mechanical and Biofunctional Systems, Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Yuki Ito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
| | - Yasuro Furuichi
- Department of Health Promotion Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Yasuko Manabe
- Department of Health Promotion Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
| | - Nobuharu L. Fujii
- Department of Health Promotion Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, 246-2 Mizukami, Kakuganji, Tsuruoka, Yamagata 997-0052, Japan
| | - Shinya Kuroda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Bunkyo-ku, Tokyo 113-0033, Japan
- Corresponding author
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11
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Abstract
Dysfunction in the contractile properties of the diaphragm muscle contributes to the morbidity and mortality in many neuromuscular and respiratory diseases. Methods that can accurately quantify diaphragm function in mouse models are essential for preclinical studies. Diaphragm function is usually measured using the diaphragm strip. Two methods have been used to attach the diaphragm strip to the force transducer. The suture method is easy to adopt but it cannot maintain the physiological orientation of the muscle fibers. Hence, results may not accurately reflect diaphragm contractility. The clamp method can better maintain diaphragm muscle fiber orientation but is used less often because detailed information on clamp fabrication and application has never been published. Importantly, a side-by-side comparison of the two methods is lacking. To address these questions, we engineered diaphragm clamps using mechanically highly durable material. Here, we present a detailed and ready-to-use protocol on the design and manufacture of diaphragm clamps. Also, we present a step by step protocol on how to mount the diaphragm strip to the clamp and then to the muscle force measurement system. We compared the diaphragm force from the same mouse with both suture and clamp methods. We found the clamp method yielded a significantly higher muscle force. Finally, we validated the utility of the clamp method in the mdx model of Duchenne muscular dystrophy. In summary, the clamp method described in this paper yields reliable and consistent diaphragm force data. This method will be useful to any laboratory interested in performing mouse diaphragm function assay.
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12
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Pedersen KK, Nielsen OB, Overgaard K. Contractile benefits of doublet-initiated low-frequency stimulation in rat extensor digitorum longus muscle exposed to high extracellular [K +] or fatiguing contractions. Am J Physiol Cell Physiol 2019; 317:C39-C47. [PMID: 30969780 DOI: 10.1152/ajpcell.00519.2018] [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] [Indexed: 11/22/2022]
Abstract
During dynamic contractions, high-frequency muscle activation is needed to achieve optimal power. This must be balanced against an increased excitation-induced accumulation of extracellular K+, which can reduce excitability and ultimately may prevent adequate responses to high-frequency activation. Mean activation frequencies in vivo are often low (subtetanic), but activation patterns contain bursts of high (supratetanic) frequencies known as doublets, which enhance dynamic contraction in rested muscles at normal extracellular K+ concentration ([K+]o). Here, we examine how dynamic contractions in fast-twitch fibers stimulated by high frequency/doublets are affected during exposure to 11 mM [K+]o and during fatigue. Dynamic contractions were elicited by electrical stimulation in isolated rat extensor digitorum longus muscles incubated at 4 or 11 mM K+. When stimulation frequency was maintained constant, an increase from 150 to 300 Hz enhanced maximal power (Pmax), maximal velocity (Vmax), and rate of force development (RFD) at 4 mM K+ but only Vmax at 11 mM K+. With the use of subtetanic frequency trains (50 Hz) with or without an initiating doublet (300 Hz), the addition of a doublet increased maximal force, Pmax, Vmax, and RFD at both 4 and 11 mM K+. Furthermore, a work-matched fatiguing protocol was performed comparing a doublet-initiated subtetanic train (DT) of 60 Hz with a constant-frequency train (CFT) of 71 Hz during 100 dynamic contractions. We found that DT produced higher power, velocity, and RFD than CFT throughout the fatiguing protocol. The results indicate that doublets enhance dynamic contraction in fast-twitch muscles stimulated at subtetanic frequency during both normal and fatiguing conditions.
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Affiliation(s)
| | - Ole Bækgaard Nielsen
- Department of Public Health, Aarhus University , Aarhus , Denmark.,Department of Biomedicine, Aarhus University , Aarhus , Denmark
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13
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Banan Sadeghian R, Ebrahimi M, Salehi S. Electrical stimulation of microengineered skeletal muscle tissue: Effect of stimulus parameters on myotube contractility and maturation. J Tissue Eng Regen Med 2017. [PMID: 28622706 DOI: 10.1002/term.2502] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Skeletal muscle tissues engineered in vitro are aneural, are short in the number of fibres required to function properly and degenerate rapidly. Electrical stimulation has been widely used to compensate for such a lack of neural activity, yet the relationship between the stimulation parameters and the tissue response is subject to debate. Here we studied the effect of overnight electrical stimulation (training) on the contractility and maturity of aligned C2C12 myotubes developed on micropatterned gelatin methacryloyl (GelMA) substrates. Bipolar rectangular pulse (BRP) trains with frequency, half-duration and applied pulse train amplitudes of f = 1 Hz, ton = 0.5 ms and Vapp = {3 V, 4 V, 4.5 V}, respectively, were applied for 12 h to the myotubes formed on the microgrooved substrates. Aligned myotubes were contracting throughout the training period for Vapp ≥ 4 V. Immediately after training, the samples were subjected to series of BRPs with 2 ≤ Vapp ≤ 5 V and 0.2 ≤ ton ≤ 0.9 ms, during which myotube contraction dynamics were recorded. Analysis of post-training contraction revealed that only the myotubes trained at Vapp = 4 V displayed consistent and repeatable contraction profiles, showing the dynamics of myotube contractility as a function of triggering pulse voltage and current amplitudes, duration and imposed electrical energy. In addition, myotubes trained at Vapp = 4 V displayed amplified expression levels of genes pertinent to sarcomere development correlated with myotube maturation. Our findings are imperative for a better understanding of the influence of electrical pulses on the maturation of microengineered myotubes.
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Affiliation(s)
| | - Majid Ebrahimi
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
| | - Sahar Salehi
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
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14
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Optogenetic approach for targeted activation of global calcium transients in differentiated C2C12 myotubes. Sci Rep 2017; 7:11108. [PMID: 28894267 PMCID: PMC5593883 DOI: 10.1038/s41598-017-11551-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/14/2017] [Indexed: 12/22/2022] Open
Abstract
Excitation-contraction coupling in muscle cells is initiated by a restricted membrane depolarization delimited within the neuromuscular junction. This targeted depolarization triggers an action potential that propagates and induces a global cellular calcium response and a consequent contraction. To date, numerous studies have investigated this excitation-calcium response coupling by using different techniques to depolarize muscle cells. However, none of these techniques mimic the temporal and spatial resolution of membrane depolarization observed in the neuromuscular junction. By using optogenetics in C2C12 muscle cells, we developed a technique to study the calcium response following membrane depolarization induced by photostimulations of membrane surface similar or narrower than the neuromuscular junction area. These stimulations coupled to confocal calcium imaging generate a global cellular calcium response that is the consequence of a membrane depolarization propagation. In this context, this technique provides an interesting, contactless and relatively easy way of investigation of calcium increase/release as well as calcium decrease/re-uptake triggered by a propagated membrane depolarization.
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15
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Kasper AM, Turner DC, Martin NRW, Sharples AP. Mimicking exercise in three-dimensional bioengineered skeletal muscle to investigate cellular and molecular mechanisms of physiological adaptation. J Cell Physiol 2017; 233:1985-1998. [DOI: 10.1002/jcp.25840] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 02/02/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Andreas M. Kasper
- Stem Cells, Ageing, and Molecular Physiology (SCAMP) Unit, Exercise Metabolism and Adaptation Research group, Research Institute for Sport and Exercise Sciences (RISES), School of Sport and Exercise Sciences; Liverpool John Moores University; Liverpool UK
| | - Daniel C. Turner
- Stem Cells, Ageing, and Molecular Physiology (SCAMP) Unit, Exercise Metabolism and Adaptation Research group, Research Institute for Sport and Exercise Sciences (RISES), School of Sport and Exercise Sciences; Liverpool John Moores University; Liverpool UK
| | - Neil R. W. Martin
- Musculoskeletal Biology Research Group, School of Sport, Exercise, and Health Sciences; Loughborough University; Loughborough UK
| | - Adam P. Sharples
- Stem Cells, Ageing, and Molecular Physiology (SCAMP) Unit, Exercise Metabolism and Adaptation Research group, Research Institute for Sport and Exercise Sciences (RISES), School of Sport and Exercise Sciences; Liverpool John Moores University; Liverpool UK
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16
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Sierra M, Grasa J, Muñoz MJ, Miana-Mena FJ, González D. Predicting muscle fatigue: a response surface approximation based on proper generalized decomposition technique. Biomech Model Mechanobiol 2016; 16:625-634. [PMID: 27714474 DOI: 10.1007/s10237-016-0841-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/27/2016] [Indexed: 11/30/2022]
Abstract
A novel technique is proposed to predict force reduction in skeletal muscle due to fatigue under the influence of electrical stimulus parameters and muscle physiological characteristics. Twelve New Zealand white rabbits were divided in four groups ([Formula: see text]) to obtain the active force evolution of in vitro Extensor Digitorum Longus muscles for an hour of repeated contractions under different electrical stimulation patterns. Left and right muscles were tested, and a total of 24 samples were used to construct a response surface based in the proper generalized decomposition. After the response surface development, one additional rabbit was used to check the predictive potential of the technique. This multidimensional surface takes into account not only the decay of the maximum repeated peak force, but also the shape evolution of each contraction, muscle weight, electrical input signal and stimulation protocol. This new approach of the fatigue simulation challenge allows to predict, inside the multispace surface generated, the muscle response considering other stimulation patterns, different tissue weight, etc.
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Affiliation(s)
- M Sierra
- Applied Mechanics and Bioengineering group (AMB). Aragón Institute of Engineering Research (I3A), Universidad de Zaragoza, Zaragoza, Spain
| | - J Grasa
- Applied Mechanics and Bioengineering group (AMB). Aragón Institute of Engineering Research (I3A), Universidad de Zaragoza, Zaragoza, Spain
| | - M J Muñoz
- Laboratorio de Genética Bioquímica (LAGENBIO), Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain
| | - F J Miana-Mena
- Applied Mechanics and Bioengineering group (AMB). Aragón Institute of Engineering Research (I3A), Universidad de Zaragoza, Zaragoza, Spain.
| | - D González
- Applied Mechanics and Bioengineering group (AMB). Aragón Institute of Engineering Research (I3A), Universidad de Zaragoza, Zaragoza, Spain
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17
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Role of dystroglycan in limiting contraction-induced injury to the sarcomeric cytoskeleton of mature skeletal muscle. Proc Natl Acad Sci U S A 2016; 113:10992-7. [PMID: 27625424 DOI: 10.1073/pnas.1605265113] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dystroglycan (DG) is a highly expressed extracellular matrix receptor that is linked to the cytoskeleton in skeletal muscle. DG is critical for the function of skeletal muscle, and muscle with primary defects in the expression and/or function of DG throughout development has many pathological features and a severe muscular dystrophy phenotype. In addition, reduction in DG at the sarcolemma is a common feature in muscle biopsies from patients with various types of muscular dystrophy. However, the consequence of disrupting DG in mature muscle is not known. Here, we investigated muscles of transgenic mice several months after genetic knockdown of DG at maturity. In our study, an increase in susceptibility to contraction-induced injury was the first pathological feature observed after the levels of DG at the sarcolemma were reduced. The contraction-induced injury was not accompanied by increased necrosis, excitation-contraction uncoupling, or fragility of the sarcolemma. Rather, disruption of the sarcomeric cytoskeleton was evident as reduced passive tension and decreased titin immunostaining. These results reveal a role for DG in maintaining the stability of the sarcomeric cytoskeleton during contraction and provide mechanistic insight into the cause of the reduction in strength that occurs in muscular dystrophy after lengthening contractions.
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18
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Uesugi K, Shimizu K, Akiyama Y, Hoshino T, Iwabuchi K, Morishima K. Contractile Performance and Controllability of Insect Muscle-Powered Bioactuator with Different Stimulation Strategies for Soft Robotics. Soft Robot 2016. [DOI: 10.1089/soro.2015.0014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Kaoru Uesugi
- Department of Mechanical Engineering, Osaka University, Suita, Japan
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Koshi Shimizu
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Yoshitake Akiyama
- Department of Mechanical Engineering, Osaka University, Suita, Japan
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan
- Faculty of Textile Science and Technology, Shinshu University, Ueda, Japan
| | - Takayuki Hoshino
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan
- Department of Mathematical Engineering and Information Physics, University of Tokyo, Tokyo, Japan
| | - Kikuo Iwabuchi
- Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Keisuke Morishima
- Department of Mechanical Engineering, Osaka University, Suita, Japan
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan
- Global Center for Medical Engineering and Informatics, Osaka University, Suita, Japan
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19
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Hernández-Ochoa EO, Vanegas C, Iyer SR, Lovering RM, Schneider MF. Alternating bipolar field stimulation identifies muscle fibers with defective excitability but maintained local Ca(2+) signals and contraction. Skelet Muscle 2016; 6:6. [PMID: 26855765 PMCID: PMC4743112 DOI: 10.1186/s13395-016-0076-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 01/05/2016] [Indexed: 11/25/2022] Open
Abstract
Background Most cultured enzymatically dissociated adult myofibers exhibit spatially uniform (UNI) contractile responses and Ca2+ transients over the entire myofiber in response to electric field stimuli of either polarity applied via bipolar electrodes. However, some myofibers only exhibit contraction and Ca2+ transients at alternating (ALT) ends in response to alternating polarity field stimulation. Here, we present for the first time the methodology for identification of ALT myofibers in primary cultures and isolated muscles, as well as a study of their electrophysiological properties. Results We used high-speed confocal microscopic Ca2+ imaging, electric field stimulation, microelectrode recordings, immunostaining, and confocal microscopy to characterize the properties of action potential-induced Ca2+ transients, contractility, resting membrane potential, and staining of T-tubule voltage-gated Na+ channel distribution applied to cultured adult myofibers. Here, we show for the first time, with high temporal and spatial resolution, that normal control myofibers with UNI responses can be converted to ALT response myofibers by TTX addition or by removal of Na+ from the bathing medium, with reappearance of the UNI response on return of Na+. Our results suggest disrupted excitability as the cause of ALT behavior and indicate that the ALT response is due to local depolarization-induced Ca2+ release, whereas the UNI response is triggered by action potential propagation over the entire myofiber. Consistent with this interpretation, local depolarizing monopolar stimuli give uniform (propagated) responses in UNI myofibers, but only local responses at the electrode in ALT myofibers. The ALT responses in electrically inexcitable myofibers are consistent with expectations of current spread between bipolar stimulating electrodes, entering (hyperpolarizing) one end of a myofiber and leaving (depolarizing) the other end of the myofiber. ALT responses were also detected in some myofibers within intact isolated whole muscles from wild-type and MDX mice, demonstrating that ALT responses can be present before enzymatic dissociation. Conclusions We suggest that checking for ALT myofiber responsiveness by looking at the end of a myofiber during alternating polarity stimuli provides a test for compromised excitability of myofibers, and could be used to identify inexcitable, damaged or diseased myofibers by ALT behavior in healthy and diseased muscle. Electronic supplementary material The online version of this article (doi:10.1186/s13395-016-0076-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, 108 N. Greene Street, Baltimore, MD 21201 USA
| | - Camilo Vanegas
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, 108 N. Greene Street, Baltimore, MD 21201 USA
| | - Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, 108 N. Greene Street, Baltimore, MD 21201 USA
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20
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Selvin D, Renaud JM. Changes in myoplasmic Ca2+ during fatigue differ between FDB fibers, between glibenclamide-exposed and Kir6.2-/- fibers and are further modulated by verapamil. Physiol Rep 2015; 3:3/3/e12303. [PMID: 25742954 PMCID: PMC4393149 DOI: 10.14814/phy2.12303] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
One objective of this study was to document how individual FDB muscle fibers depend on the myoprotection of KATP channels during fatigue. Verapamil, a CaV1.1 channel blocker, prevents large increases in unstimulated force during fatigue in KATP-channel-deficient muscles. A second objective was to determine if verapamil reduces unstimulated [Ca(2+)]i in KATP-channel-deficient fibers. We measured changes in myoplasmic [Ca(2+)] ([Ca(2+)]i) using two KATP-channel-deficient models: (1) a pharmacological approach exposing fibers to glibenclamide, a channel blocker, and (2) a genetic approach using fibers from null mice for the Kir6.2 gene. Fatigue was elicited with one tetanic contraction every sec for 3 min. For all conditions, large differences in fatigue kinetics were observed from fibers which had greater tetanic [Ca(2+)]i at the end than at the beginning of fatigue to fibers which eventually completely failed to release Ca(2+) upon stimulation. Compared to control conditions, KATP-channel-deficient fibers had a greater proportion of fiber with large decreases in tetanic [Ca(2+)]i, fade and complete failure to release Ca(2+) upon stimulation. There was, however, a group of KATP-channel-deficient fibers that had similar fatigue kinetics to those of the most fatigue-resistant control fibers. For the first time, differences in fatigue kinetics were observed between Kir6.2(-/-) and glibenclamide-exposed muscle fibers. Verapamil significantly reduced unstimulated and tetanic [Ca(2+)]i. It is concluded that not all fibers are dependent on the myoprotection of KATP channels and that the decrease in unstimulated force by verapamil reported in a previous studies in glibenclamide-exposed fibers is due to a reduction in Ca(2+) load by reducing Ca(2+) influx through CaV1.1 channels between and during contractions.
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Affiliation(s)
- David Selvin
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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21
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Rizzuto E, Pisu S, Musarò A, Del Prete Z. Measuring Neuromuscular Junction Functionality in the SOD1(G93A) Animal Model of Amyotrophic Lateral Sclerosis. Ann Biomed Eng 2015; 43:2196-206. [PMID: 25631208 PMCID: PMC4516896 DOI: 10.1007/s10439-015-1259-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/17/2015] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that leads to motor neuron degeneration, alteration in neuromuscular junctions (NMJs), muscle atrophy, and paralysis. To investigate the NMJ functionality in ALS we tested, in vitro, two innervated muscle types excised from SOD1G93A transgenic mice at the end-stage of the disease: the Soleus, a postural muscle almost completely paralyzed at that stage, and the diaphragm, which, on the contrary, is functional until death. To this aim we employed an experimental protocol that combined two types of electrical stimulation: the direct stimulation and the stimulation through the nerve. The technique we applied allowed us to determine the relevance of NMJ functionality separately from muscle contractile properties in SOD1G93A animal model. Functional measurements revealed that the muscle contractility of transgenic diaphragms is almost unaltered in comparison to control muscles, while transgenic Soleus muscles were severely compromised. In contrast, when stimulated via the nerve, both transgenic muscle types showed a strong decrease of the contraction force, a slowing down of the kinetic parameters, as well as alterations in the neurotransmission failure parameter. All together, these results confirm a severely impaired functionality in the SOD1G93A neuromuscular junctions.
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Affiliation(s)
- Emanuele Rizzuto
- Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, 00184, Rome, Italy,
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22
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Cairns SP, Leader JP, Loiselle DS, Higgins A, Lin W, Renaud JM. Extracellular Ca2+-induced force restoration in K+-depressed skeletal muscle of the mouse involves an elevation of [K+]i: implications for fatigue. J Appl Physiol (1985) 2015; 118:662-74. [PMID: 25571990 DOI: 10.1152/japplphysiol.00705.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined whether a Ca(2+)-K(+) interaction was a potential mechanism operating during fatigue with repeated tetani in isolated mouse muscles. Raising the extracellular Ca(2+) concentration ([Ca(2+)]o) from 1.3 to 10 mM in K(+)-depressed slow-twitch soleus and/or fast-twitch extensor digitorum longus muscles caused the following: 1) increase of intracellular K(+) activity by 20-60 mM (raised intracellular K(+) content, unchanged intracellular fluid volume), so that the K(+)-equilibrium potential increased by ∼10 mV and resting membrane potential repolarized by 5-10 mV; 2) large restoration of action potential amplitude (16-54 mV); 3) considerable recovery of excitable fibers (∼50% total); and 4) restoration of peak force with the peak tetanic force-extracellular K(+) concentration ([K(+)]o) relationship shifting rightward toward higher [K(+)]o. Double-sigmoid curve-fitting to fatigue profiles (125 Hz for 500 ms, every second for 100 s) showed that prior exposure to raised [K(+)]o (7 mM) increased, whereas lowered [K(+)]o (2 mM) decreased, the rate and extent of force loss during the late phase of fatigue (second sigmoid) in soleus, hence implying a K(+) dependence for late fatigue. Prior exposure to 10 mM [Ca(2+)]o slowed late fatigue in both muscle types, but was without effect on the extent of fatigue. These combined findings support our notion that a Ca(2+)-K(+) interaction is plausible during severe fatigue in both muscle types. We speculate that a diminished transsarcolemmal K(+) gradient and lowered [Ca(2+)]o contribute to late fatigue through reduced action potential amplitude and excitability. The raised [Ca(2+)]o-induced slowing of fatigue is likely to be mediated by a higher intracellular K(+) activity, which prolongs the time before stimulation-induced K(+) efflux depolarizes the sarcolemma sufficiently to interfere with action potentials.
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Affiliation(s)
- Simeon P Cairns
- Sports Performance Research Institute New Zealand, School of Sport and Recreation, Faculty of Health and Environmental Sciences, AUT University, Auckland, New Zealand; Health and Rehabilitation Research Institute, Faculty of Health and Environmental Sciences, AUT University, Auckland, New Zealand;
| | - John P Leader
- Department of Medicine, University of Otago, Dunedin, New Zealand; Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Denis S Loiselle
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand; Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand; and
| | - Amanda Higgins
- Department of Cellular and Molecular Medicine, Center for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Wei Lin
- Department of Cellular and Molecular Medicine, Center for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Center for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
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23
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Selvin D, Hesse E, Renaud JM. Properties of single FDB fibers following a collagenase digestion for studying contractility, fatigue, and pCa-sarcomere shortening relationship. Am J Physiol Regul Integr Comp Physiol 2015; 308:R467-79. [PMID: 25568074 DOI: 10.1152/ajpregu.00144.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this study was to optimize the approach to obtain viable single flexor digitorum brevis (FDB) fibers following a collagenase digestion. A first aim was to determine the culture medium conditions for the collagenase digestion. The MEM yielded better fibers in terms of morphology and contractility than the DMEM. The addition of FBS to culture media was crucial to prevent fiber supercontraction. The addition of FBS to the physiological solution used during an experiment was also beneficial, especially during fatigue. Optimum FBS concentration in MEM was 10% (vol/vol), and for the physiological solution, it ranged between 0.2 and 1.0%. A second aim was to document the stability of single FDB fibers. If tested the day of the preparation, most fibers (∼80%) had stable contractions for up to 3 h, normal stimulus duration strength to elicit contractions, and normal and stable resting membrane potential during prolonged microelectrode penetration. A third aim was to document their fatigue kinetics. Major differences in fatigue resistance were observed between fibers as expected from the FDB fiber-type composition. All sarcoplasmic [Ca(2+)] and sarcomere length parameters returned to their prefatigue levels after a short recovery. The pCa-sarcomere shortening relationship of unfatigued fibers is very similar to the pCa-force curve reported in other studies. The pCa-sarcomere shortening from fatigue data is complicated by large decreases in sarcomere length between contractions. It is concluded that isolation of single fibers by a collagenase digestion is a viable preparation to study contractility and fatigue kinetics.
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Affiliation(s)
- David Selvin
- University of Ottawa, Department of Cellular and Molecular Medicine, Ottawa, Ontario, Canada
| | - Erik Hesse
- University of Ottawa, Department of Cellular and Molecular Medicine, Ottawa, Ontario, Canada
| | - Jean-Marc Renaud
- University of Ottawa, Department of Cellular and Molecular Medicine, Ottawa, Ontario, Canada
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24
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Ito A, Yamamoto Y, Sato M, Ikeda K, Yamamoto M, Fujita H, Nagamori E, Kawabe Y, Kamihira M. Induction of functional tissue-engineered skeletal muscle constructs by defined electrical stimulation. Sci Rep 2014; 4:4781. [PMID: 24759171 PMCID: PMC3998029 DOI: 10.1038/srep04781] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/07/2014] [Indexed: 11/08/2022] Open
Abstract
Electrical impulses are necessary for proper in vivo skeletal muscle development. To fabricate functional skeletal muscle tissues in vitro, recapitulation of the in vivo niche, including physical stimuli, is crucial. Here, we report a technique to engineer skeletal muscle tissues in vitro by electrical pulse stimulation (EPS). Electrically excitable tissue-engineered skeletal muscle constructs were stimulated with continuous electrical pulses of 0.3 V/mm amplitude, 4 ms width, and 1 Hz frequency, resulting in a 4.5-fold increase in force at day 14. In myogenic differentiation culture, the percentage of peak twitch force (%Pt) was determined as the load on the tissue constructs during the artificial exercise induced by continuous EPS. We optimized the stimulation protocol, wherein the tissues were first subjected to 24.5%Pt, which was increased to 50-60%Pt as the tissues developed. This technique may be a useful approach to fabricate tissue-engineered functional skeletal muscle constructs.
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Affiliation(s)
- Akira Ito
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- These authors contributed equally to this work
| | - Yasunori Yamamoto
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- These authors contributed equally to this work
| | - Masanori Sato
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kazushi Ikeda
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Masahiro Yamamoto
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hideaki Fujita
- Toyota Central R&D Laboratories Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
- Current address: Laboratory for Comprehensive Bioimaging, Riken Qbic, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
| | - Eiji Nagamori
- Toyota Central R&D Laboratories Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
- Current address: Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yoshinori Kawabe
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Masamichi Kamihira
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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Grasa J, Sierra M, Muñoz MJ, Soteras F, Osta R, Calvo B, Miana-Mena FJ. On simulating sustained isometric muscle fatigue: a phenomenological model considering different fiber metabolisms. Biomech Model Mechanobiol 2014; 13:1373-85. [DOI: 10.1007/s10237-014-0579-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/26/2014] [Indexed: 11/29/2022]
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Oki K, Wiseman RW, Breedlove SM, Jordan CL. Androgen receptors in muscle fibers induce rapid loss of force but not mass: implications for spinal bulbar muscular atrophy. Muscle Nerve 2013; 47:823-34. [PMID: 23629944 DOI: 10.1002/mus.23813] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2013] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Testosterone (T) induces motor dysfunction in transgenic (Tg) mice that overexpress wild-type androgen receptor (AR) in skeletal muscles. Because many genes implicated in motor neuron disease are expressed in skeletal muscle, mutant proteins may act in muscle to cause dysfunction in motor neuron disease. METHODS We examined contractile properties of the extensor digitorum longus (EDL) and soleus (SOL) muscles in vitro after 5 and 3 days of T treatment in motor-impaired Tg female mice. RESULTS Both muscles showed deficits in tetanic force after 5 days of T treatment, without losses in muscle mass, protein content, or fiber number. After 3 days of T treatment, only SOL showed a deficit in tetanic force comparable to that of 5 days of treatment. In both treatments, EDL showed slowed twitch kinetics, whereas SOL showed deficits in the twitch/tetanus ratio. CONCLUSIONS These results suggest calcium-handling mechanisms in muscle fibers are defective in motor-impaired mice.
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Affiliation(s)
- Kentaro Oki
- Neuroscience Program, Michigan State University, 108 Giltner Hall, 293 Farm Lane, East Lansing, Michigan 48824-1101, USA
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Weber H, Rauch A, Adamski S, Chakravarthy K, Kulkarni A, Dogdas B, Bendtsen C, Kath G, Alves SE, Wilkinson HA, Chiu CS. Automated rodent in situ muscle contraction assay and myofiber organization analysis in sarcopenia animal models. J Appl Physiol (1985) 2012; 112:2087-98. [PMID: 22461442 DOI: 10.1152/japplphysiol.00871.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Age-related sarcopenia results in frailty and decreased mobility, which are associated with increased falls and long-term disability in the elderly. Given the global increase in lifespan, sarcopenia is a growing, unmet medical need. This report aims to systematically characterize muscle aging in preclinical models, which may facilitate the development of sarcopenia therapies. Naïve rats and mice were subjected to noninvasive micro X-ray computed tomography (micro-CT) imaging, terminal in situ muscle function characterizations, and ATPase-based myofiber analysis. We developed a Definiens (Parsippany, NJ)-based algorithm to automate micro-CT image analysis, which facilitates longitudinal in vivo muscle mass analysis. We report development and characterization of translational in situ skeletal muscle performance assay systems in rat and mouse. The systems incorporate a custom-designed animal assay stage, resulting in enhanced force measurement precision, and LabVIEW (National Instruments, Austin, TX)-based algorithms to support automated data acquisition and data analysis. We used ATPase-staining techniques for myofibers to characterize fiber subtypes and distribution. Major parameters contributing to muscle performance were identified using data mining and integration, enabled by Labmatrix (BioFortis, Columbia, MD). These technologies enabled the systemic and accurate monitoring of muscle aging from a large number of animals. The data indicated that longitudinal muscle cross-sectional area measurement effectively monitors change of muscle mass and function during aging. Furthermore, the data showed that muscle performance during aging is also modulated by myofiber remodeling factors, such as changes in myofiber distribution patterns and changes in fiber shape, which affect myofiber interaction. This in vivo muscle assay platform has been applied to support identification and validation of novel targets for the treatment of sarcopenia.
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Affiliation(s)
- H. Weber
- Musculo-Skeletal Biology Program Team, Merck Research Laboratories, West Point, Pennsylvania
| | - A. Rauch
- Bioelectronics, Merck Research Laboratories, West Point, Pennsylvania
| | - S. Adamski
- Musculo-Skeletal Biology Program Team, Merck Research Laboratories, West Point, Pennsylvania
| | - K. Chakravarthy
- Musculo-Skeletal Biology Program Team, Merck Research Laboratories, West Point, Pennsylvania
| | - A. Kulkarni
- Musculo-Skeletal Biology Program Team, Merck Research Laboratories, West Point, Pennsylvania
| | - B. Dogdas
- Informatics IT, Merck Research Laboratories, West Point, Pennsylvania
| | - C. Bendtsen
- Merck Research Laboratories, IRBM, Rome, Italy; and
| | - G. Kath
- Bioelectronics, Merck Research Laboratories, Rahway, New Jersey
| | - S. E. Alves
- Musculo-Skeletal Biology Program Team, Merck Research Laboratories, West Point, Pennsylvania
| | - H. A. Wilkinson
- Musculo-Skeletal Biology Program Team, Merck Research Laboratories, West Point, Pennsylvania
| | - C-S. Chiu
- Musculo-Skeletal Biology Program Team, Merck Research Laboratories, West Point, Pennsylvania
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Khodabukus A, Baar K. Defined Electrical Stimulation Emphasizing Excitability for the Development and Testing of Engineered Skeletal Muscle. Tissue Eng Part C Methods 2012; 18:349-57. [DOI: 10.1089/ten.tec.2011.0364] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Alastair Khodabukus
- Division of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
| | - Keith Baar
- Division of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California
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29
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Cairns SP, Leader JP, Loiselle DS. Exacerbated potassium-induced paralysis of mouse soleus muscle at 37°C vis-à-vis 25°C: implications for fatigue. Pflugers Arch 2011; 461:469-79. [DOI: 10.1007/s00424-011-0927-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 12/21/2010] [Accepted: 01/14/2011] [Indexed: 10/18/2022]
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Donnelly K, Khodabukus A, Philp A, Deldicque L, Dennis RG, Baar K. A novel bioreactor for stimulating skeletal muscle in vitro. Tissue Eng Part C Methods 2010; 16:711-8. [PMID: 19807268 DOI: 10.1089/ten.tec.2009.0125] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
For over 300 years, scientists have understood that stimulation, in the form of an electrical impulse, is required for normal muscle function. More recently, the role of specific parameters of the electrical impulse (i.e., the pulse amplitude, pulse width, and work-to-rest ratio) has become better appreciated. However, most existing bioreactor systems do not permit sufficient control over these parameters. Therefore, the aim of the current study was to engineer an inexpensive muscle electrical stimulation bioreactor to apply physiologically relevant electrical stimulation patterns to tissue-engineered muscles and monolayers in culture. A low-powered microcontroller and a DC-DC converter were used to power a pulse circuit that converted a 4.5 V input to outputs of up to 50 V, with pulse widths from 0.05 to 4 ms, and frequencies up to 100 Hz (with certain operational limitations). When two-dimensional cultures were stimulated at high frequencies (100 Hz), this resulted in an increase in the rate of protein synthesis (at 12 h, control [CTL] = 5.0 + or - 0.16; 10 Hz = 5.0 + or - 0.07; and 100 Hz = 5.5 + or - 0.13 fmol/min/mg) showing that this was an anabolic signal. When three-dimensional engineered muscles were stimulated at 0.1 ms and one or two times rheobase, stimulation improved force production (CTL = 0.07 + or - 0.009; 1.25 V/mm = 0.10 + or - 0.011; 2.5 V/mm = 0.14146 + or - 0.012; and 5 V/mm = 0.03756 + or - 0.008 kN/mm(2)) and excitability (CTL = 0.53 + or - 0.022; 1.25 V/mm = 0.44 + or - 0.025; 2.5 V/mm = 0.41 + or - 0.012; and 5 V/mm = 0.60 + or - 0.021 V/mm), suggesting enhanced maturation. Together, these data show that the physiology and function of muscles can be improved in vitro using a bioreactor that allows the control of pulse amplitude, pulse width, pulse frequency, and work-to-rest ratio.
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Affiliation(s)
- Kenneth Donnelly
- Division of Mechanical Engineering and Mechatronics, University of Dundee, Dundee, United Kingdom
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31
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Hamilton DL, Philp A, MacKenzie MG, Baar K. A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise. PLoS One 2010; 5:e11624. [PMID: 20661274 PMCID: PMC2905373 DOI: 10.1371/journal.pone.0011624] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 06/22/2010] [Indexed: 11/25/2022] Open
Abstract
Background Since activation of the PI3K/(protein kinase B; PKB/akt) pathway has been shown to alter muscle mass and growth, the aim of this study was to determine whether resistance exercise increased insulin like growth factor (IGF) I/phosphoinositide 3-kinase (PI3K) signalling and whether altering PI(3,4,5)P3 metabolism genetically would increase load induced muscle growth. Methodology/Principal Findings Acute and chronic resistance exercise in wild type and muscle specific PTEN knockout mice were used to address the role of PI(3,4,5)P3 regulation in the development of skeletal muscle hypertrophy. Acute resistance exercise did not increase either IGF-1 receptor phosphorylation or IRS1/2 associated p85. Since insulin/IGF signalling to PI3K was unchanged, we next sought to determine whether inactivation of PTEN played a role in load-induced muscle growth. Muscle specific knockout of PTEN resulted in small but significant increases in heart (PTEN+/+ = 5.00±0.02 mg/g, PTEN−/− = 5.50±0.09 mg/g), and TA (PTEN+/+ = 1.74±0.04 mg/g, PTEN−/− = 1.89 ±0.03) muscle mass, while the GTN, SOL, EDL and PLN remain unchanged. Following ablation, hypertrophy of the PLN, SOL or EDL muscles was similar between PTEN−/− and PTEN+/+ animals. Even though there were some changes in overload-induced PKB and S6K1 phosphorylation, 1 hr following acute resistance exercise there was no difference in the phosphorylation state of S6K1 Thr389 between genotypes. Conclusions/Significance These data suggest that physiological loading does not lead to the enhanced activation of the PI3K/PKB/mTORC1 axis and that neither PI3K activation nor PTEN, and by extension PI(3,4,5)P3 levels, play a significant role in adult skeletal muscle growth.
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Affiliation(s)
- D. Lee Hamilton
- Division of Molecular Physiology, University of Dundee, Dundee, Scotland, United Kingdom
| | - Andrew Philp
- Division of Molecular Physiology, University of Dundee, Dundee, Scotland, United Kingdom
| | - Matthew G. MacKenzie
- Division of Molecular Physiology, University of Dundee, Dundee, Scotland, United Kingdom
| | - Keith Baar
- Division of Molecular Physiology, University of Dundee, Dundee, Scotland, United Kingdom
- * E-mail:
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Burch N, Arnold AS, Item F, Summermatter S, Brochmann Santana Santos G, Christe M, Boutellier U, Toigo M, Handschin C. Electric pulse stimulation of cultured murine muscle cells reproduces gene expression changes of trained mouse muscle. PLoS One 2010; 5:e10970. [PMID: 20532042 PMCID: PMC2881042 DOI: 10.1371/journal.pone.0010970] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 05/13/2010] [Indexed: 12/20/2022] Open
Abstract
Adequate levels of physical activity are at the center of a healthy lifestyle. However, the molecular mechanisms that mediate the beneficial effects of exercise remain enigmatic. This gap in knowledge is caused by the lack of an amenable experimental model system. Therefore, we optimized electric pulse stimulation of muscle cells to closely recapitulate the plastic changes in gene expression observed in a trained skeletal muscle. The exact experimental conditions were established using the peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) as a marker for an endurance-trained muscle fiber. We subsequently compared the changes in the relative expression of metabolic and myofibrillar genes in the muscle cell system with those observed in mouse muscle in vivo following either an acute or repeated bouts of treadmill exercise. Importantly, in electrically stimulated C2C12 mouse muscle cells, the qualitative transcriptional adaptations were almost identical to those in trained muscle, but differ from the acute effects of exercise on muscle gene expression. In addition, significant alterations in the expression of myofibrillar proteins indicate that this stimulation could be used to modulate the fiber-type of muscle cells in culture. Our data thus describe an experimental cell culture model for the study of at least some of the transcriptional aspects of skeletal muscle adaptation to physical activity. This system will be useful for the study of the molecular mechanisms that regulate exercise adaptation in muscle.
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Affiliation(s)
- Nathalie Burch
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Exercise Physiology, Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland
| | - Anne-Sophie Arnold
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Biozentrum, Department of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland
| | - Flurin Item
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Exercise Physiology, Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland
| | - Serge Summermatter
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Biozentrum, Department of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland
| | | | - Martine Christe
- Biozentrum, Department of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland
| | - Urs Boutellier
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Exercise Physiology, Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland
| | - Marco Toigo
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Exercise Physiology, Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland
| | - Christoph Handschin
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Biozentrum, Department of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland
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Quiñonez M, González F, Morgado-Valle C, DiFranco M. Effects of membrane depolarization and changes in extracellular [K(+)] on the Ca (2+) transients of fast skeletal muscle fibers. Implications for muscle fatigue. J Muscle Res Cell Motil 2010; 31:13-33. [PMID: 20049631 PMCID: PMC2908756 DOI: 10.1007/s10974-009-9195-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 12/11/2009] [Indexed: 12/02/2022]
Abstract
Repetitive activation of skeletal muscle fibers leads to a reduced transmembrane K+ gradient. The resulting membrane depolarization has been proposed to play a major role in the onset of muscle fatigue. Nevertheless, raising the extracellular K+ (\documentclass[12pt]{minimal}
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\begin{document}$$ [ {\text{K}}^{ + } ]_{\text{o}} $$\end{document}) to 10 mM potentiates twitch force of rested amphibian and mammalian fibers. We used a double Vaseline gap method to simultaneously record action potentials (AP) and Ca2+ transients from rested frog fibers activated by single and tetanic stimulation (10 pulses, 100 Hz) at various \documentclass[12pt]{minimal}
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\begin{document}$$ [ {\text{K}}^{ + } ]_{\text{o}} $$\end{document} and membrane potentials. Depolarization resulting from current injection or raised \documentclass[12pt]{minimal}
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\begin{document}$$ [ {\text{K}}^{ + } ]_{\text{o}} $$\end{document} produced an increase in the resting [Ca2+]. Ca2+ transients elicited by single stimulation were potentiated by depolarization from −80 to −60 mV but markedly depressed by further depolarization. Potentiation was inversely correlated with a reduction in the amplitude, overshoot and duration of APs. Similar effects were found for the Ca2+ transients elicited by the first pulse of 100 Hz trains. Depression or block of Ca2+ transient in response to the 2nd to 10th pulses of 100 Hz trains was observed at smaller depolarizations as compared to that seen when using single stimulation. Changes in Ca2+ transients along the trains were associated with impaired or abortive APs. Raising \documentclass[12pt]{minimal}
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\begin{document}$$ [ {\text{K}}^{ + } ]_{\text{o}} $$\end{document} to 15 mM markedly depressed both responses. The effects of 10 mM \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{K}}_{\text{o}}^{ + } $$\end{document} on Ca2+ transients, but not those of 15 mM \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{K}}_{\text{o}}^{ + } $$\end{document}, could be fully reversed by hyperpolarization. The results suggests that the force potentiating effects of 10 mM \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{K}}_{\text{o}}^{ + } $$\end{document} might be mediated by depolarization dependent changes in resting [Ca2+] and Ca2+ release, and that additional mechanisms might be involved in the effects of 15 mM \documentclass[12pt]{minimal}
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\begin{document}$$ {\text{K}}_{\text{o}}^{ + } $$\end{document} on force generation.
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Affiliation(s)
- Marbella Quiñonez
- Laboratorio de Fisiología y Biofisíca del Músculo, IBE, UCV, Caracas, Venezuela.
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Feng HZ, Wei B, Jin JP. Deletion of a genomic segment containing the cardiac troponin I gene knocks down expression of the slow troponin T gene and impairs fatigue tolerance of diaphragm muscle. J Biol Chem 2009; 284:31798-806. [PMID: 19797054 DOI: 10.1074/jbc.m109.020826] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The loss of slow skeletal muscle troponin T (TnT) results in a recessive nemaline myopathy in the Amish featured with lethal respiratory failure. The genes encoding slow TnT and cardiac troponin I (TnI) are closely linked. Ex vivo promoter analysis suggested that the 5'-enhancer region of the slow TnT gene overlaps with the structure of the upstream cardiac TnI gene. Using transgenic expression of exogenous cardiac TnI to rescue the postnatal lethality of a mouse line in which the entire cardiac TnI gene was deleted, we investigated the effect of enhancer deletion on slow TnT gene expression in vivo and functional consequences. The levels of slow TnT mRNA and protein were significantly reduced in the diaphragm muscle of adult double transgenic mice. The slow TnT-deficient (ssTnT-KD) diaphragm muscle exhibited atrophy and decreased ratios of slow versus fast isoforms of TnT, TnI, and myosin. Consistent with the changes toward more fast myofilament contents, ssTnT-KD diaphragm muscle required stimulation at higher frequency for optimal tetanic force production. The ssTnT-KD diaphragm muscle also exhibited significantly reduced fatigue tolerance, showing faster and more declines of force with slower and less recovery from fatigue as compared with the wild type controls. The natural switch to more slow fiber contents during aging was partially blunted in the ssTnT-KD skeletal muscle. The data demonstrated a critical role of slow TnT in diaphragm function and in the pathogenesis and pathophysiology of Amish nemaline myopathy.
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Affiliation(s)
- Han-Zhong Feng
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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35
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Cairns SP, Taberner AJ, Loiselle DS. Changes of surface and t-tubular membrane excitability during fatigue with repeated tetani in isolated mouse fast- and slow-twitch muscle. J Appl Physiol (1985) 2009; 106:101-12. [DOI: 10.1152/japplphysiol.90878.2008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated whether impaired sarcolemmal excitability causes severe fatigue during repeated tetani in isolated mouse skeletal muscle. Slow-twitch soleus or fast-twitch extensor digitorum longus (EDL) muscles underwent intensive stimulation (standard protocol: 125 Hz for 500 ms, every second, parallel plate electrodes, 20 V, 0.1-ms pulses). Interventions with altered stimulation characteristics were tested either on the entire fatigue profile or after 90- to 100-s stimulation. d-tubocurarine did not alter the fatigue profile in soleus thereby eliminating impaired neuromuscular transmission. Lower stimulation frequencies partially restored peak force, especially in soleus. The twitch force-stimulation strength relationship shifted towards higher voltages in both muscle types, with a much larger shift in EDL. Augmenting pulse strength restored tetanic force from 29% (4.4 V) to 79% (20 V), or slowed fatigue in soleus. Increasing pulse duration (0.1 to 1.0 ms) restored tetanic force from 8 to 46% in EDL and from 41 to 90% in soleus; 0.25-ms pulses restored tetanic force to 83% in soleus. Switching from transverse wire to parallel plate stimulation increased tetanic force from 34 to 63%, and fatigue was exacerbated with wires compared with plates in soleus. The combined data suggest that impaired excitability (disrupted action potential generation) within trains is the main contributor (∼50% initial force) to severe fatigue in both muscle types, the surface rather than t-tubular membrane is the main site of impairment during wire stimulation, and extreme fatigue in EDL includes an increased action potential threshold leading to inexcitable fibers. Moreover, mathematical modeling discounts anoxia as the major contributor to fatigue during our stimulation regime in isolated muscles.
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Cairns SP, Robinson DM, Loiselle DS. Double-sigmoid model for fitting fatigue profiles in mouse fast- and slow-twitch muscle. Exp Physiol 2008; 93:851-62. [DOI: 10.1113/expphysiol.2007.041285] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cairns SP, Lindinger MI. Do multiple ionic interactions contribute to skeletal muscle fatigue? J Physiol 2008; 586:4039-54. [PMID: 18591187 DOI: 10.1113/jphysiol.2008.155424] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
During intense exercise or electrical stimulation of skeletal muscle the concentrations of several ions change simultaneously in interstitial, transverse tubular and intracellular compartments. Consequently the functional effects of multiple ionic changes need to be considered together. A diminished transsarcolemmal K(+) gradient per se can reduce maximal force in non-fatigued muscle suggesting that K(+) causes fatigue. However, this effect requires extremely large, although physiological, K(+) shifts. In contrast, moderate elevations of extracellular [K(+)] ([K(+)](o)) potentiate submaximal contractions, enhance local blood flow and influence afferent feedback to assist exercise performance. Changed transsarcolemmal Na(+), Ca(2+), Cl(-) and H(+) gradients are insufficient by themselves to cause much fatigue but each ion can interact with K(+) effects. Lowered Na(+), Ca(2+) and Cl(-) gradients further impair force by modulating the peak tetanic force-[K(+)](o) and peak tetanic force-resting membrane potential relationships. In contrast, raised [Ca(2+)](o), acidosis and reduced Cl(-) conductance during late fatigue provide resistance against K(+)-induced force depression. The detrimental effects of K(+) are exacerbated by metabolic changes such as lowered [ATP](i), depleted carbohydrate, and possibly reactive oxygen species. We hypothesize that during high-intensity exercise a rundown of the transsarcolemmal K(+) gradient is the dominant cellular process around which interactions with other ions and metabolites occur, thereby contributing to fatigue.
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Affiliation(s)
- S P Cairns
- Institute of Sport and Recreation Research New Zealand, Faculty of Health and Environmental Sciences, AUT University, Auckland 1020, New Zealand.
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