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Henin G, Loumaye A, Deldicque L, Leclercq IA, Lanthier N. Unlocking liver health: Can tackling myosteatosis spark remission in metabolic dysfunction-associated steatotic liver disease? Liver Int 2024; 44:1781-1796. [PMID: 38623714 DOI: 10.1111/liv.15938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 03/12/2024] [Accepted: 04/02/2024] [Indexed: 04/17/2024]
Abstract
Myosteatosis is highly prevalent in metabolic dysfunction-associated steatotic liver disease (MASLD) and could reciprocally impact liver function. Decreasing muscle fat could be indirectly hepatoprotective in MASLD. We conducted a review to identify interventions reducing myosteatosis and their impact on liver function. Non-pharmacological interventions included diet (caloric restriction or lipid enrichment), bariatric surgery and physical activity. Caloric restriction in humans achieving a mean weight loss of 3% only reduces muscle fat. Lipid-enriched diet increases liver fat in human with no impact on muscle fat, except sphingomyelin-enriched diet which reduces both lipid contents exclusively in pre-clinical studies. Bariatric surgery, hybrid training (resistance exercise and electric stimulation) or whole-body vibration in human decrease both liver and muscle fat. Physical activity impacts both phenotypes by reducing local and systemic inflammation, enhancing insulin sensitivity and modulating the expression of key mediators of the muscle-liver-adipose tissue axis. The combination of diet and physical activity acts synergistically in liver, muscle and white adipose tissue, and further decrease muscle and liver fat. Several pharmacological interventions (patchouli alcohol, KBP-089, 2,4-dinitrophenol methyl ether, adipoRon and atglistatin) and food supplementation (vitamin D or resveratrol) improve liver and muscle phenotypes in pre-clinical studies by increasing fatty acid oxidation and anti-inflammatory properties. These interventions are effective in reducing myosteatosis in MASLD while addressing the liver disease itself. This review supports that disturbances in inter-organ crosstalk are key pathophysiological mechanisms involved in MASLD and myosteatosis pathogenesis. Focusing on the skeletal muscle might offer new therapeutic strategies to treat MASLD by modulating the interactions between liver and muscles.
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Affiliation(s)
- Guillaume Henin
- Service d'Hépato-Gastroentérologie, Cliniques universitaires Saint-Luc, UCLouvain, Brussels, Belgium
- Laboratory of Hepatogastroenterology, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain (UCLouvain), Brussels, Belgium
| | - Audrey Loumaye
- Service d'Endocrinologie, Diabétologie et Nutrition, Cliniques universitaires Saint-Luc, UCLouvain, Brussels, Belgium
| | | | - Isabelle A Leclercq
- Laboratory of Hepatogastroenterology, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain (UCLouvain), Brussels, Belgium
| | - Nicolas Lanthier
- Service d'Hépato-Gastroentérologie, Cliniques universitaires Saint-Luc, UCLouvain, Brussels, Belgium
- Laboratory of Hepatogastroenterology, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain (UCLouvain), Brussels, Belgium
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Molecular and Metabolic Mechanism of Low-Intensity Pulsed Ultrasound Improving Muscle Atrophy in Hindlimb Unloading Rats. Int J Mol Sci 2021; 22:ijms222212112. [PMID: 34829990 PMCID: PMC8625684 DOI: 10.3390/ijms222212112] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/31/2021] [Accepted: 11/02/2021] [Indexed: 12/16/2022] Open
Abstract
Low-intensity pulsed ultrasound (LIPUS) has been proved to promote the proliferation of myoblast C2C12. However, whether LIPUS can effectively prevent muscle atrophy has not been clarified, and if so, what is the possible mechanism. The aim of this study is to evaluate the effects of LIPUS on muscle atrophy in hindlimb unloading rats, and explore the mechanisms. The rats were randomly divided into four groups: normal control group (NC), hindlimb unloading group (UL), hindlimb unloading plus 30 mW/cm2 LIPUS irradiation group (UL + 30 mW/cm2), hindlimb unloading plus 80 mW/cm2 LIPUS irradiation group (UL + 80 mW/cm2). The tails of rats in hindlimb unloading group were suspended for 28 days. The rats in the LIPUS treated group were simultaneously irradiated with LIPUS on gastrocnemius muscle in both lower legs at the sound intensity of 30 mW/cm2 or 80 mW/cm2 for 20 min/d for 28 days. C2C12 cells were exposed to LIPUS at 30 or 80 mW/cm2 for 5 days. The results showed that LIPUS significantly promoted the proliferation and differentiation of myoblast C2C12, and prevented the decrease of cross-sectional area of muscle fiber and gastrocnemius mass in hindlimb unloading rats. LIPUS also significantly down regulated the expression of MSTN and its receptors ActRIIB, and up-regulated the expression of Akt and mTOR in gastrocnemius muscle of hindlimb unloading rats. In addition, three metabolic pathways (phenylalanine, tyrosine and tryptophan biosynthesis; alanine, aspartate and glutamate metabolism; glycine, serine and threonine metabolism) were selected as important metabolic pathways for hindlimb unloading effect. However, LIPUS promoted the stability of alanine, aspartate and glutamate metabolism pathway. These results suggest that the key mechanism of LIPUS in preventing muscle atrophy induced by hindlimb unloading may be related to promoting protein synthesis through MSTN/Akt/mTOR signaling pathway and stabilizing alanine, aspartate and glutamate metabolism.
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Effects of Traditional Chinese Acupuncture Compared with Sham Acupuncture on the Explosive Force Production by the Forearm Muscles in Female: A Randomized Controlled Trial. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:1992753. [PMID: 34484385 PMCID: PMC8413022 DOI: 10.1155/2021/1992753] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/05/2021] [Accepted: 08/16/2021] [Indexed: 11/17/2022]
Abstract
Background Acupuncture can effectively enhance musculoskeletal rehabilitation, with effects such as reduced pain intensity and muscle tension and decreased disability. Objective The purpose of this study was to determine the efficacy of traditional Chinese acupuncture (TCA) compared with sham acupuncture (SA) in explosive force production by the forearm muscles in females. Methods A total of 32 subjects were included and randomly assigned to two groups: TCA group (n = 16): stimulated specific acupoints including Quchi (LI11), Shousanli (LI10), Hegu (LI4), Xiaohai (SI8), Tianjing (SJ10), and Waiguan (SJ5) for 15 minutes; SA group (n = 16): using superficial needle insertion at nonacupoints without stimulation. The subjects warmed up for the 3-time isokinetic test with an angular velocity of 30°/s and then performed a set of 15 full flexion (Flex) and extension (Ext) with an angular velocity of 180°/s using the CON-TREX isokinetic test training system recorded as the pretest. After acupuncture for 15 min, perform a set of the same isokinetic movement isokinetic records as the posttest. The average max torque, average work, average power, average peak power, average max speed, and total work were collected to evaluate the forearm explosive force changes. Use two-way repeated measures ANOVA to compare the difference before and after acupuncture between two groups. Results The results showed that acupuncture conditions (sham acupuncture as well as true acupuncture) and the intervention times (not acupuncture or acupuncture for 15 min) have a significant interaction effect on forearm explosive force and joint stiffness (P < 0.05). The simple main effect showed that the selected parameters of the TCA group increased significantly after acupuncture (P < 0.05), while the SA group did not (P > 0.05). We speculate that the activation of muscle may be related to the selected acupuncture points. Conclusion Acupuncture can produce excitation in motor nerves and muscles, and nerve stimulation increases the recruitment of motor units, thus improving the muscle explosive force.
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Hashida R, Takano Y, Matsuse H, Kudo M, Bekki M, Omoto M, Nago T, Kawaguchi T, Torimura T, Shiba N. Electrical Stimulation of the Antagonist Muscle During Cycling Exercise Interval Training Improves Oxygen Uptake and Muscle Strength. J Strength Cond Res 2021; 35:111-117. [PMID: 29278576 DOI: 10.1519/jsc.0000000000002393] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Hashida, R, Takano, Y, Matsuse, H, Kudo, M, Bekki, M, Omoto, M, Nago, T, Kawaguchi, T, Torimura, T, and Shiba, N. Electrical stimulation of the antagonist muscle during cycling exercise interval training improves oxygen uptake and muscle strength. J Strength Cond Res 35(1): 111-117, 2021-A hybrid training system (HTS) is a resistance exercise method that combines voluntary concentric muscle contractions and electrically stimulated eccentric muscle contractions. We devised an exercise technique using HTS on cycle ergometer (HCE). The purpose of this study was to compare cardiorespiratory function and muscle strength when cycling exercise is combined with electrical stimulation over an extended period. Twenty-nine healthy young men were divided into an HCE group (n = 14) and a volitional cycle ergometer (VCE alone) group (n = 15). All subjects performed 30-minute cycling exercise interval training sessions 3 times a week for 6 weeks. The V̇o2peak of both groups significantly increased compared with the pretraining period (HCE group: from 31.3 ± 4.4 [ml·kg-1·min-1] pretraining to 37.6 ± 6.7 [ml·kg-1·min-1] post-training [p = 0.0024] and VCE group: from 34.0 ± 7.1 [ml·kg-1·min-1] pretraining to 38.4 ± 8.2 [ml·kg-1·min-1] [p = 0.0057]). After the training, there was no significant difference of changes in V̇o2peak between the HCE and the VCE groups (p = 0.7107). In the VCE group, the maximal isokinetic torque of knee extension (60°·s-1) post-training did not significantly increase compared with the pretraining period (VCE group: from 2.4 ± 0.5 [N·m·kg-1] pretraining to 2.5 ± 0.4 [N·m·kg-1] [p = 0.4543]). By contrast, in the HCE group, the maximal isokinetic torque of knee extension (60°·s-1) post-training significantly increased compared with pretraining period (HCE group: from 2.5 ± 0.3 [N·m·kg-1] pretraining to 2.8 ± 0.3 [N·m·kg-1] [p < 0.0001]). The change in knee extension torque was significantly greater for the HCE group than for the VCE group (p = 0.0307). In conclusion, cardiopulmonary function and knee extension strength were improved by the use of HCE.
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Affiliation(s)
- Ryuki Hashida
- Division of Rehabilitation, Kurume University Hospital, Kurume, Japan.,Department of Orthopedics, Kurume University School of Medicine, Kurume, Japan
| | - Yoshio Takano
- Department of Physical Therapy, School of Health Sciences, International University Health and Welfare, Enokizu, Okawa, Japan; and
| | - Hiroo Matsuse
- Division of Rehabilitation, Kurume University Hospital, Kurume, Japan.,Department of Orthopedics, Kurume University School of Medicine, Kurume, Japan
| | - Mei Kudo
- Division of Rehabilitation, Kurume University Hospital, Kurume, Japan
| | - Masafumi Bekki
- Division of Rehabilitation, Kurume University Hospital, Kurume, Japan.,Department of Orthopedics, Kurume University School of Medicine, Kurume, Japan
| | - Masayuki Omoto
- Division of Rehabilitation, Kurume University Hospital, Kurume, Japan.,Department of Orthopedics, Kurume University School of Medicine, Kurume, Japan
| | - Takeshi Nago
- Division of Rehabilitation, Kurume University Hospital, Kurume, Japan.,Department of Orthopedics, Kurume University School of Medicine, Kurume, Japan
| | - Takumi Kawaguchi
- Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan
| | - Takuji Torimura
- Department of Physical Therapy, School of Health Sciences, International University Health and Welfare, Enokizu, Okawa, Japan; and
| | - Naoto Shiba
- Division of Rehabilitation, Kurume University Hospital, Kurume, Japan.,Department of Orthopedics, Kurume University School of Medicine, Kurume, Japan
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Qaisar R, Karim A, Elmoselhi AB. Muscle unloading: A comparison between spaceflight and ground-based models. Acta Physiol (Oxf) 2020; 228:e13431. [PMID: 31840423 DOI: 10.1111/apha.13431] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 12/12/2022]
Abstract
Prolonged unloading of skeletal muscle, a common outcome of events such as spaceflight, bed rest and hindlimb unloading, can result in extensive metabolic, structural and functional changes in muscle fibres. With advancement in investigations of cellular and molecular mechanisms, understanding of disuse muscle atrophy has significantly increased. However, substantial gaps exist in our understanding of the processes dictating muscle plasticity during unloading, which prevent us from developing effective interventions to combat muscle loss. This review aims to update the status of knowledge and underlying mechanisms leading to cellular and molecular changes in skeletal muscle during unloading. We have also discussed advances in the understanding of contractile dysfunction during spaceflights and in ground-based models of muscle unloading. Additionally, we have elaborated on potential therapeutic interventions that show promising results in boosting muscle mass and strength during mechanical unloading. Finally, we have identified key gaps in our knowledge as well as possible research direction for the future.
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Affiliation(s)
- Rizwan Qaisar
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
| | - Asima Karim
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
| | - Adel B. Elmoselhi
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
- Department of Physiology Michigan State University East Lansing MI USA
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Maffiuletti NA, Green DA, Vaz MA, Dirks ML. Neuromuscular Electrical Stimulation as a Potential Countermeasure for Skeletal Muscle Atrophy and Weakness During Human Spaceflight. Front Physiol 2019; 10:1031. [PMID: 31456697 PMCID: PMC6700209 DOI: 10.3389/fphys.2019.01031] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 07/26/2019] [Indexed: 01/25/2023] Open
Abstract
Human spaceflight is associated with a substantial loss of skeletal muscle mass and muscle strength. Neuromuscular electrical stimulation (NMES) evokes involuntary muscle contractions, which have the potential to preserve or restore skeletal muscle mass and neuromuscular function during and/or post spaceflight. This assumption is largely based on evidence from terrestrial disuse/immobilization studies without the use of large exercise equipment that may not be available in spaceflight beyond the International Space Station. In this mini-review we provide an overview of the rationale and evidence for NMES based on the terrestrial state-of-the-art knowledge, compare this to that used in orbit, and in ground-based analogs in order to provide practical recommendations for implementation of NMES in future space missions. Emphasis will be placed on knee extensor and plantar flexor muscles known to be particularly susceptible to deconditioning in space missions.
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Affiliation(s)
| | - David A Green
- Space Medicine Team, HRE-OM, European Astronaut Centre, European Space Agency, Cologne, Germany.,KBRwyle, Wyle Laboratories GmbH, Cologne, Germany.,King's College London, Centre for Human & Applied Physiological Sciences (CHAPS), London, United Kingdom
| | - Marco Aurelio Vaz
- Exercise Research Laboratory (LAPEX), Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Marlou L Dirks
- Department of Sport and Health Sciences, University of Exeter, Exeter, United Kingdom
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McNamara KP, Greene KA, Moore AM, Lenchik L, Weaver AA. Lumbopelvic Muscle Changes Following Long-Duration Spaceflight. Front Physiol 2019; 10:627. [PMID: 31164840 PMCID: PMC6536568 DOI: 10.3389/fphys.2019.00627] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/02/2019] [Indexed: 12/25/2022] Open
Abstract
Long-duration spaceflight has been shown to negatively affect the lumbopelvic muscles of crewmembers. Through analysis of computed tomography scans of crewmembers on 4- to 6-month missions equipped with the interim resistive exercise device, the structural deterioration of the psoas, quadratus lumborum, and paraspinal muscles was assessed. Computed tomography scans of 16 crewmembers were collected before and after long-duration spaceflight. The volume and attenuation of lumbar musculature at the L2 vertebral level were measured. Percent changes in the lumbopelvic muscle volume and attenuation (indicative of myosteatosis, or intermuscular fat infiltration) following spaceflight were calculated. Due to historical studies demonstrating only decreases in the muscles assessed, a one-sample t test was performed to determine if these decreases persist in more recent flight conditions. Crewmembers on interim resistive exercise device-equipped missions experienced an average 9.5% (2.0% SE) decrease in volume and 6.0% (1.5% SE) decrease in attenuation in the quadratus lumborum muscles and an average 5.3% (1.0% SE) decrease in volume and 5.3% (1.6% SE) decrease in attenuation in the paraspinal muscles. Crewmembers experienced no significant changes in psoas muscle volume or attenuation. No significant changes in intermuscular adipose tissue volume or attenuation were found in any muscles. Long-duration spaceflight was associated with preservation of psoas muscle volume and attenuation and significant decreases in quadratus lumborum and paraspinal muscle volume and attenuation.
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Affiliation(s)
- Kyle P McNamara
- Center of Injury Biomechanics, Virginia Tech - Wake Forest University School of Biomedical Engineering and Sciences, Winston-Salem, NC, United States
| | - Katelyn A Greene
- Center of Injury Biomechanics, Virginia Tech - Wake Forest University School of Biomedical Engineering and Sciences, Winston-Salem, NC, United States
| | - Austin M Moore
- Center of Injury Biomechanics, Virginia Tech - Wake Forest University School of Biomedical Engineering and Sciences, Winston-Salem, NC, United States
| | - Leon Lenchik
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Ashley A Weaver
- Center of Injury Biomechanics, Virginia Tech - Wake Forest University School of Biomedical Engineering and Sciences, Winston-Salem, NC, United States
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Rabe KG, Matsuse H, Jackson A, Segal NA. Evaluation of the Combined Application of Neuromuscular Electrical Stimulation and Volitional Contractions on Thigh Muscle Strength, Knee Pain, and Physical Performance in Women at Risk for Knee Osteoarthritis: A Randomized Controlled Trial. PM R 2018; 10:1301-1310. [PMID: 29852286 DOI: 10.1016/j.pmrj.2018.05.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 04/18/2018] [Accepted: 05/05/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND Knee osteoarthritis (OA) is a leading cause of disability that is associated with quadriceps weakness. However, strengthening in people with or with risk factors for knee OA can be poorly tolerated. OBJECTIVE To assess the efficacy of a 12-week low-load exercise program, using a hybrid training system (HTS) that uses the combination of neuromuscular electrical stimulation and volitional contractions, for improving thigh muscle strength, knee pain relief, and physical performance in women with or with risk factors for knee OA. DESIGN Randomized, single-blinded, controlled trial. SETTING Exercise training laboratory. PARTICIPANTS Forty-two women 44-85 years old with risk factors for knee OA. INTERVENTIONS Participants randomized to 12 weeks of biweekly low-load resistance training with the HTS or on an isokinetic dynamometer (control). OUTCOMES Maximum isokinetic knee extensor torque. Secondary measures included maximum isokinetic knee flexor torque, knee pain (Knee Injury and Osteoarthritis Outcome Score), and timed 20-m walk and chair stand tests. RESULTS The HTS and control treatments resulted in muscle strengthening, decreased knee pain, and improved physical performance. HTS group quadriceps and hamstring strength increased by 0.06 ± 0.04 Nm/kg (P > .05) and 0.05 ± 0.02 Nm/kg (P = .02), respectively. Control group quadriceps and hamstring strength increased by 0.03 ± 0.04 Nm/kg (P > .05) and 0.06 ± 0.02 Nm/kg (P = .009), respectively. Knee pain decreased by 11.9 ± 11.5 points (P < .001) for the HTS group and 14.1 ± 15.4 points (P = .001) for the control group. The 20-m walk time decreased by 1.60 ± 2.04 seconds (P = .005) and 0.95 ± 1.2 seconds (P = .004), and chair stand time decreased by 4.8 ± 10.0 seconds (P > .05) and 1.9 ± 4.7 seconds (P > .05) in the HTS and control groups, respectively. These results did not differ statistically between the HTS and control groups. CONCLUSIONS These results suggest the HTS is effective for alleviating pain and improving physical performance in women with risk factors for knee OA. However, the HTS does not appear to be superior to low-load resistance training for improving muscle strength, pain relief, or physical function. CLINICAL TRIAL REGISTRATION NUMBER NCT02802878. LEVEL OF EVIDENCE I.
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Affiliation(s)
- Kaitlin G Rabe
- Department of Rehabilitation Medicine, The University of Kansas, Kansas City, KS(∗)
| | - Hiroo Matsuse
- Department of Orthopedics, Kurume University School of Medicine, Kurume, Fukuoka, Japan(†)
| | - Anthony Jackson
- Department of Rehabilitation Medicine, The University of Kansas, Kansas City, KS(‡)
| | - Neil A Segal
- Department of Rehabilitation Medicine, University of Kansas Medical Center, 3901 Rainbow Blvd, MS 1046, Kansas City, KS 66160(§).
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Tanaka K, Nishimura N, Kawai Y. Adaptation to microgravity, deconditioning, and countermeasures. J Physiol Sci 2017; 67:271-281. [PMID: 28000175 PMCID: PMC10717636 DOI: 10.1007/s12576-016-0514-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/07/2016] [Indexed: 02/01/2023]
Abstract
Humans are generally in standing or sitting positions on Earth during the day. The musculoskeletal system supports these positions and also allows motion. Gravity acting in the longitudinal direction of the body generates a hydrostatic pressure difference and induces footward fluid shift. The vestibular system senses the gravity of the body and reflexively controls the organs. During spaceflight or exposure to microgravity, the load on the musculoskeletal system and hydrostatic pressure difference is diminished. Thus, the skeletal muscle, particularly in the lower limbs, is atrophied, and bone minerals are lost via urinary excretion. In addition, the heart is atrophied, and the plasma volume is decreased, which may induce orthostatic intolerance. Vestibular-related control also declines; in particular, the otolith organs are more susceptible to exposure to microgravity than the semicircular canals. Using an advanced resistive exercise device with administration of bisphosphonate is an effective countermeasure against bone deconditioning. However, atrophy of skeletal muscle and the heart has not been completely prevented. Further ingenuity is needed in designing countermeasures for muscular, cardiovascular, and vestibular dysfunctions.
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Affiliation(s)
- Kunihiko Tanaka
- Graduate School of Health and Medicine, Gifu University of Medical Science, 795-1 Nagamine Ichihiraga, Seki, Gifu, 501-3892, Japan.
| | - Naoki Nishimura
- Department of Physiology, Faculty of Medicine, Aichi Medical School, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1103, Japan
| | - Yasuaki Kawai
- Division of Adaptation Physiology, Faculty of Medicine, Tottori University, 86 Nishi-machi, Yonago, Tottori, 683-8503, Japan
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Hessel AL, Lindstedt SL, Nishikawa KC. Physiological Mechanisms of Eccentric Contraction and Its Applications: A Role for the Giant Titin Protein. Front Physiol 2017; 8:70. [PMID: 28232805 PMCID: PMC5299520 DOI: 10.3389/fphys.2017.00070] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/25/2017] [Indexed: 12/11/2022] Open
Abstract
When active muscles are stretched, our understanding of muscle function is stretched as well. Our understanding of the molecular mechanisms of concentric contraction has advanced considerably since the advent of the sliding filament theory, whereas mechanisms for increased force production during eccentric contraction are only now becoming clearer. Eccentric contractions play an important role in everyday human movements, including mobility, stability, and muscle strength. Shortly after the sliding filament theory of muscle contraction was introduced, there was a reluctant recognition that muscle behaved as if it contained an "elastic" filament. Jean Hanson and Hugh Huxley referred to this structure as the "S-filament," though their concept gained little traction. This additional filament, the giant titin protein, was identified several decades later, and its roles in muscle contraction are still being discovered. Recent research has demonstrated that, like activation of thin filaments by calcium, titin is also activated in muscle sarcomeres by mechanisms only now being elucidated. The mdm mutation in mice appears to prevent activation of titin, and is a promising model system for investigating mechanisms of titin activation. Titin stiffness appears to increase with muscle force production, providing a mechanism that explains two fundamental properties of eccentric contractions: their high force and low energetic cost. The high force and low energy cost of eccentric contractions makes them particularly well suited for athletic training and rehabilitation. Eccentric exercise is commonly prescribed for treatment of a variety of conditions including sarcopenia, osteoporosis, and tendinosis. Use of eccentric exercise in rehabilitation and athletic training has exploded to include treatment for the elderly, as well as muscle and bone density maintenance for astronauts during long-term space travel. For exercise intolerance and many types of sports injuries, experimental evidence suggests that interventions involving eccentric exercise are demonstrably superior to conventional concentric interventions. Future work promises to advance our understanding of the molecular mechanisms that confer high force and low energy cost to eccentric contraction, as well as signaling mechanisms responsible for the beneficial effects of eccentric exercise in athletic training and rehabilitation.
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Affiliation(s)
| | | | - Kiisa C. Nishikawa
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona UniversityFlagstaff, AZ, USA
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Shiba N, Matsuse H, Takano Y, Yoshimitsu K, Omoto M, Hashida R, Tagawa Y, Inada T, Yamada S, Ohshima H. Correction: Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut--Initial Verification on the International Space Station. PLoS One 2015; 10:e0138519. [PMID: 26368534 PMCID: PMC4569477 DOI: 10.1371/journal.pone.0138519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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