Ground-Based Analogs for Human Spaceflight

Pandiarajan, Meenakshi; Hargens, Alan R.

doi:10.3389/fphys.2020.00716

Cited by 71 publications

(59 citation statements)

References 24 publications

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“…Using this method, a relatively large number of studies performed under real and simulated microgravity conditions has been carried out ( Lee et al, 2014 ; Schneider et al, 2015 ; Treffel et al, 2016 ; de Abreu et al, 2017 ; Rukavishnikov et al, 2017 ; Schoenrock et al, 2018 ). The Dry Immersion (DI) model is used less often than the bed rest model, but it reproduces neuromuscular deconditioning quite accurately ( Navasiolava et al, 2011 ; Watenpaugh, 2016 ; Tomilovskaya et al, 2019 ; Pandiarajan and Hargens, 2020 ). All studies, even with short exposures such as parabolic flight or several hours of DI, have shown a decrease in muscle tone.…”

Section: Introductionmentioning

confidence: 99%

Sharp Changes in Muscle Tone in Humans Under Simulated Microgravity

et al. 2021

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A decrease in muscle tone induced by space flight requires a standardized assessment of changes to control the state of the neuromuscular system. This study is a step toward the development of a unified protocol, aimed at determining the initial effect of the presence or withdrawal of support on muscle tone, the effects of a 2-h supportlessness in Dry Immersion (DI) experiments, and the changes in muscle tone depending on the site of measurement. To perform measurements of changes in muscle tone, we used a MyotonPRO device. The list of muscles that we assessed includes: trunk – mm. deltoideus posterior, trapezius, erector spinae; leg – mm. biceps femoris, rectus femoris, tibialis anterior, soleus, gastrocnemius; foot – m. flexor digitorum brevis, tendo Achillis, aponeurosis plantaris. The study involved 12 healthy volunteers (6 men, 6 women) without musculoskeletal disorders and aged 32.8 ± 1.6 years. At the start of DI, there was a significant decrease in muscle tone of the following muscles: mm. tibialis anterior (−10.9%), soleus (−9.6%), erector spinae (−14.4%), and the tendo Achillis (−15.3%). The decrease continued to intensify over the next 2 h. In contrast, the gastrocnemius muscle demonstrated an increase in muscle tone (+7.5%) 2 h after the start of DI compared to the immediate in-bath baseline. Muscle tone values were found to be site-dependent and varied in different projections of mm. erector spinae and soleus. In previous experiments, we observed a high sensitivity of the myotonometry technique, which was confirmed in this study. To make it possible to compare data from different studies, a standardized protocol for measuring muscle tone for general use in gravitational physiology needs to be developed.

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Section: Introductionmentioning

confidence: 99%

Sharp Changes in Muscle Tone in Humans Under Simulated Microgravity

et al. 2021

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“…It has also been shown that in a short time, within 3–7 days, there is a change in the sensorimotor functions: a decrease in accuracy of movement control, decline in the accuracy of visual tracking, and an increased sensitivity to vestibular signals. The physiological aspects of these models, obtained from participation of male volunteers, are described in details in the review articles ( Pavy-Le Traon et al, 2007 ; Navasiolava et al, 2011 ; Watenpaugh, 2016 ; Tomilovskaya et al, 2019 ; Pandiarajan and Hargens, 2020 ). However, studies involving this model in women have never been conducted, in part, due to a number of hygienic and physiological difficulties.…”

Section: Introductionmentioning

confidence: 99%

The First Female Dry Immersion (NAIAD-2020): Design and Specifics of a 3-Day Study

et al. 2021

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This article describes procedures and some results of the first study of females undergoing 3-day Dry Immersion. The experiment “NAIAD-2020” was carried out at the Institute of Biomedical Problems (Moscow, Russia) with the participation of six healthy women volunteers (age 30.17 ± 5.5 years, height 1.66 ± 0.1 m, weight 62.05 ± 8.4 kg, BMI 22.39 ± 2.2 kg/m2) with a natural menstrual cycle. During the study, a standard protocol was used, the same as for men, with a minimum period of time spent outside the immersion bath. Before, during and after Immersion, 22 experiments were carried out aimed at studying the neurophysiological, functional, metabolic and psychophysiological functions of the body, the results of which will be presented in future publications. The total time outside the bath for women did not exceed that for men. Systolic and diastolic pressure did not significantly change during the immersion. In the first 24 h after the end of the immersion, heart rate was significantly higher than the background values [F(4,20) = 14.67; P < 0.0001]. Changes in body temperature and water balance were consistent with the patterns found in men. No significant changes in height and weight were found during immersion. All women reported general discomfort and pain in the abdomen and back. The results of this study did not find significant risks to women’s health and showed the feasibility of using this model of the effects of space flight in women of reproductive age.

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“…Terrestrial-based analogs for LDSF have been of longstanding interest in space medicine research as simulated microgravity is an efficient platform to observe physiology in extreme situations. Analogs such as supine bed rest, head-down tilt bed rest (HDTBR), wet immersion, dry immersion, and lower-extremity limb suspension have been previously applied as earthbound experimental models to further understand the human body during spaceflight (24). HDTBR studies serve as a terrestrial analog by altering the vector of gravitational force on the body to generate a cephalad fluid shift similar to that seen in microgravity (43)(44)(45).…”

Section: Head-down Tilt Bed Rest Studies and Clinical Findingsmentioning

confidence: 99%

“…Though other techniques such as parabolic flight more closely simulate the actual microgravity condition, the brief duration of exposure is not sufficient for manifestation of SANS-like features. In contrast, long-duration HDTBR is feasible with study durations of 370 days having been successfully completed ( 24 , 47 ). Furthermore, many outcomes analogous to those used by NASA for study of astronauts (MRI, OCT, LP etc.)…”

Section: Head-down Tilt Bed Rest Studies and Clinical Findingsmentioning

confidence: 99%

Head-Down Tilt Bed Rest Studies as a Terrestrial Analog for Spaceflight Associated Neuro-Ocular Syndrome

2021

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Astronauts who undergo prolonged periods of spaceflight may develop a unique constellation of neuro-ocular findings termed Spaceflight Associated Neuro-Ocular Syndrome (SANS). SANS is a disorder that is unique to spaceflight and has no terrestrial equivalent. The prevalence of SANS increases with increasing spaceflight duration and although there have been residual, structural, ocular changes noted, no irreversible or permanent visual loss has occurred after SANS, with the longest spaceflight to date being 14 months. These microgravity-induced findings are being actively investigated by the United States' National Aeronautics Space Administration (NASA) and SANS is a potential obstacle to future longer duration, manned, deep space flight missions. The pathophysiology of SANS remains incompletely understood but continues to be a subject of intense study by NASA and others. The study of SANS is of course partially limited by the small sample size of humans undergoing spaceflight. Therefore, identifying a terrestrial experimental model of SANS is imperative to facilitate its study and for testing of preventative measures and treatments. Head-down tilt bed rest (HDTBR) on Earth has emerged as one promising possibility. In this paper, we review the HDTBR as an analog for SANS pathogenesis; the clinical and imaging overlap between SANS and HDTBR studies; and potential SANS countermeasures that have been or could be tested with HDTBR.

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Ground-Based Analogs for Human Spaceflight

Cited by 71 publications

References 24 publications

Sharp Changes in Muscle Tone in Humans Under Simulated Microgravity

Sharp Changes in Muscle Tone in Humans Under Simulated Microgravity

The First Female Dry Immersion (NAIAD-2020): Design and Specifics of a 3-Day Study

Head-Down Tilt Bed Rest Studies as a Terrestrial Analog for Spaceflight Associated Neuro-Ocular Syndrome

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