Adaptation to microgravity, deconditioning, and countermeasures

Tanaka, Kunihiko; Nishimura, Naoki; Kawai, Yasuaki

doi:10.1007/s12576-016-0514-8

Cited by 100 publications

(90 citation statements)

References 114 publications

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“…Our results have implications to the cardiovascular deconditioning that occurs during space missions. Similarly to HDT, microgravity causes a headward shift of body fluid that in the short term elicits a reduction of blood pressure and heart rate, and in the long term leads to a reduction of baroreflex sensitivity and ultimately to orthostatic intolerance [30,20,16,53]. In this study, we showed that loading the antigravity muscles during HDT at rest causes an increase of BP that can establish similar values to those associated to orthostatic condition (i.e.…”

Section: Discussionmentioning

confidence: 49%

“…To better interpret these cardiovascular responses, it is therefore important to determine the potential role of antigravity muscle activity on cardiovascular function. Establishing this role may also contribute to a better understanding of the cardiovascular deconditioning caused by microgravity [20,16,53,7,57,8], and of the physiological processes involved in recovery from physical exercises during space missions [15,54].…”

Section: Introductionmentioning

confidence: 99%

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Cardiovascular responses to antigravity muscle loading during head-down tilt at rest and after dynamic exercises

Alessandro

Tafreshi

Riener

2018

Preprint

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The physiological processes underlying hemodynamic homeostasis can be modulated by muscle activity and gravitational loading. The effects of antigravity muscle activity on cardiovascular regulation has been observed during orthostatic stress. Here, we evaluated such effects during head-down tilt (HDT). In this posture, the gravitational gradient along the body is different than in upright position, leading to increased central blood volume and reduced venous pooling. We compared the cardiovascular signals obtained with and without antigravity muscle loading during HDT in healthy human subjects, both at rest and during recovery from leg-press exercises. Further, we compared such cardiovascular responses to those obtained during upright position. We found that loading the antigravity muscles during HDT at rest led to significantly higher values of arterial blood pressure than without muscle loading, and restored systolic values to those observed during upright posture. Maintaining muscle loading post-exercise altered the short-term cardiovascular responses, but not the values of the signals five minutes after the exercise. These results demonstrate that antigravity muscle activity modulates cardiovascular regulation during HDT. This modulation should therefore be considered when interpreting cardiovascular responses to conditions that affect both gravity loading and muscle activity, for example bed rest or microgravity.

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Section: Discussionmentioning

confidence: 49%

Section: Introductionmentioning

confidence: 99%

Cardiovascular responses to antigravity muscle loading during head-down tilt at rest and after dynamic exercises

Alessandro

Tafreshi

Riener

2018

Preprint

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“…Microgravity in space causes various problems in different biological systems, including muscular system atrophy, immune system dysfunction, electrolyte imbalance and cardiovascular anomalies (Grimm et al, 2016;Tanaka, Nishimura, & Kawai, 2017). One of the most prominent and well recognized physiological challenges accompanying extended spaceflight is bone mass reduction and osteopenia (Grimm et al, 2016;Sun et al, 2018).…”

Section: The Primary Cilium As a Coordinator In Signal Transductionmentioning

confidence: 99%

Novel functions of the primary cilium in bone disease and cancer

Shi

Zhang

et al. 2019

Cytoskeleton

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The primary cilium, a sensory organelle that emanates from the cell surface of most mammalian cell types during growth arrest, has attracted the attention of many researchers over the past decade. Recently, a large number of new findings have assigned novel functions and roles to the primary cilium in signal transduction and related diseases, which has greatly augmented the importance of the cilium in human health and development. Here, we review emerging evidence supporting the primary cilium as a sensory organelle in signal transduction in microgravity, electromagnetic field sensing, chemosensation and tumorigenesis. We also present an overview of signal transduction crosstalk associated with the primary cilium in bone disease and cancer, including primary cilium-related Ca 2+ signaling, parathyroid hormone signaling, cAMP signaling, BMP/Smad1/5/8 signaling and Wnt signaling. We anticipate that emerging discoveries about the function of the primary cilium will provide novel insight into the molecular mechanisms of stimulus sensation, signal transduction and pathogenesis. K E Y W O R D Sbone disease, cancer, cytoskeleton, primary cilium, signal transduction

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“…Numerous attempts have been taken to replace missing gravitational loads by exercise‐based countermeasures, for example, resistance exercise . Currently, astronauts on the International Space Station (ISS) use three different exercise‐based countermeasures: treadmill, cycle ergometer, and the “Advanced Resistive Exercise Device (ARED).” Astronauts are recommended to exercise for at least two hours per day but muscle atrophy can only be reduced and not avoided with the current training regiments . This may be due to training mode or training protocols but also motivational aspects have to be taken into account as daily exercise session of two hours are not kept up by all individuals living on the ISS.…”

Section: Introductionmentioning

confidence: 99%

“…Astronauts are recommended to exercise for at least two hours per day 9 but muscle atrophy can only be reduced and not avoided with the current training regiments. 10 This may be due to training mode or training protocols but also motivational aspects have to be taken into account as daily exercise session of two hours are not kept up by all individuals living on the ISS. Therefore, different training methods and protocols are continuously investigated in order to optimize exercise-based countermeasures with regards to crew time and effectiveness.…”

mentioning

confidence: 99%

Response of thigh muscle cross‐sectional area to 21‐days of bed rest with exercise and nutrition countermeasures

et al. 2019

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Human skeletal muscle atrophies in response to reduced mechanical loading. The study aimed to define the muscle‐specific anatomical cross‐sectional area (ACSA) location that is most sensitive to immobilization and to investigate the effectiveness of resistive vibration exercise, alone, or combined with protein supplementation, against muscle atrophy. Eleven individuals (35.2 ± 8.1 years, 22.6 ± 1.7 kg/m2) were analysed in trial 1, and eight subjects (37.1 ± 6.7 years, 23.0 ± 1.8 kg/m2) in trial 2. Subject received control (CON), vibration training (RVE) (25 minutes à 2 sessions/wk), or RVE + nutrition (NEX) interventions (whey protein + potassium/bicarbonate). Magnetic resonance images (MRI) of both thighs were acquired before, during, and 6 days after 21‐days of bed rest to determine ACSAs in regions of interest (ROI) between 10% and 90% of the proximal end of the M. rectus femoris tendon and the end of the femoral neck. Muscle atrophy was highest at the location of their greatest ACSA. ACSA of all muscles at 70% of ROI was reduced after bed rest during CON (range −4.7% to −14.8%) and remained reduced after 6 days of recovery for the majority of muscles (range −3.4% to −8.3%) except for M. vastus lateralis, M. vastus medialis, M. sartorius, and knee flexors. Applied countermeasures had no effect. In conclusion, thigh muscle atrophy can be monitored using ACSA and RVE or NEX was not sufficient to prevent muscle atrophy during 21‐days bed rest.

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Adaptation to microgravity, deconditioning, and countermeasures

Cited by 100 publications

References 114 publications

Cardiovascular responses to antigravity muscle loading during head-down tilt at rest and after dynamic exercises

Cardiovascular responses to antigravity muscle loading during head-down tilt at rest and after dynamic exercises

Novel functions of the primary cilium in bone disease and cancer

Response of thigh muscle cross‐sectional area to 21‐days of bed rest with exercise and nutrition countermeasures

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