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1.
Cell Rep ; 40(10): 111279, 2022 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-36070701

RESUMO

Spaceflight poses risks to the central nervous system (CNS), and understanding neurological responses is important for future missions. We report CNS changes in Drosophila aboard the International Space Station in response to spaceflight microgravity (SFµg) and artificially simulated Earth gravity (SF1g) via inflight centrifugation as a countermeasure. While inflight behavioral analyses of SFµg exhibit increased activity, postflight analysis displays significant climbing defects, highlighting the sensitivity of behavior to altered gravity. Multi-omics analysis shows alterations in metabolic, oxidative stress and synaptic transmission pathways in both SFµg and SF1g; however, neurological changes immediately postflight, including neuronal loss, glial cell count alterations, oxidative damage, and apoptosis, are seen only in SFµg. Additionally, progressive neuronal loss and a glial phenotype in SF1g and SFµg brains, with pronounced phenotypes in SFµg, are seen upon acclimation to Earth conditions. Overall, our results indicate that artificial gravity partially protects the CNS from the adverse effects of spaceflight.


Assuntos
Gravidade Alterada , Voo Espacial , Ausência de Peso , Animais , Drosophila/genética , Drosophila melanogaster , Ausência de Peso/efeitos adversos
2.
Front Neural Circuits ; 16: 784280, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35310547

RESUMO

The altered vestibular signaling and somatosensory unloading of microgravity result in sensory reweighting and adaptation to conflicting sensory inputs. Aftereffects of these adaptive changes are evident postflight as impairments in behaviors such as balance and gait. Microgravity also induces fluid shifts toward the head and an upward shift of the brain within the skull; these changes are well-replicated in strict head-down tilt bed rest (HDBR), a spaceflight analog environment. Artificial gravity (AG) is a potential countermeasure to mitigate these effects of microgravity. A previous study demonstrated that intermittent (six, 5-mins bouts per day) daily AG sessions were more efficacious at counteracting orthostatic intolerance in a 5 day HDBR study than continuous daily AG. Here we examined whether intermittent daily AG was also more effective than continuous dosing for mitigating brain and behavioral changes in response to 60 days of HDBR. Participants (n = 24) were split evenly between three groups. The first received 30 mins of continuous AG daily (cAG). The second received 30 mins of intermittent AG daily (6 bouts of 5 mins; iAG). The third received no AG (Ctrl). We collected a broad range of sensorimotor, cognitive, and brain structural and functional assessments before, during, and after the 60 days of HDBR. We observed no significant differences between the three groups in terms of HDBR-associated changes in cognition, balance, and functional mobility. Interestingly, the intermittent AG group reported less severe motion sickness symptoms than the continuous group during centrifugation; iAG motion sickness levels were not elevated above those of controls who did not undergo AG. They also had a shorter duration of post-AG illusory motion than cAG. Moreover, the two AG groups performed the paced auditory serial addition test weekly while undergoing AG; their performance was more accurate than that of controls, who performed the test while in HDBR. Although AG did not counteract HDBR-induced gait and balance declines, iAG did not cause motion sickness and was associated with better self-motion perception during AG ramp-down. Additionally, both AG groups had superior cognitive performance while undergoing AG relative to controls; this may reflect attention or motivation differences between the groups.


Assuntos
Gravidade Alterada , Voo Espacial , Repouso em Cama , Cognição , Decúbito Inclinado com Rebaixamento da Cabeça/fisiologia , Humanos
3.
J Vestib Res ; 32(4): 305-316, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34806642

RESUMO

BACKGROUND: The cross-coupled (CC) illusion and associated motion sickness limit the tolerability of fast-spin-rate centrifugation for artificial gravity implementation. Humans acclimate to the CC illusion through repeated exposure; however, substantial inter-individual differences in acclimation exist, which remain poorly understood. To address this, we investigated several potential predictors of individual acclimation to the CC illusion. METHODS: Eleven subjects were exposed to the CC illusion for up to 50 25-minute acclimation sessions. The metric of acclimation rate was calculated as the slope of each subject's linear increase in spin rate across sessions. As potential predictors of acclimation rate, we gathered age, gender, demographics, and activity history, and measured subjects' vestibular perceptual thresholds in the yaw, pitch, and roll rotation axes. RESULTS: We found a significant, negative correlation (p = 0.025) between subjects' acclimation rate and roll threshold, suggesting lower thresholds yielded faster acclimation. Additionally, a leave-one-out cross-validation analysis indicated that roll thresholds are predictive of acclimation rates. Correlations between acclimation and other measures were not found but were difficult to assess within our sample. CONCLUSIONS: The ability to predict individual differences in CC illusion acclimation rate using roll thresholds is critical to optimizing acclimation training, improving the feasibility of fast-rotation, short-radius centrifugation for artificial gravity.


Assuntos
Gravidade Alterada , Ilusões , Enjoo devido ao Movimento , Aclimatação , Centrifugação , Humanos , Rotação
4.
Sci Rep ; 11(1): 21786, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34750416

RESUMO

Spaceflight induces hepatic damage, partially owing to oxidative stress caused by the space environment such as microgravity and space radiation. We examined the roles of anti-oxidative sulfur-containing compounds on hepatic damage after spaceflight. We analyzed the livers of mice on board the International Space Station for 30 days. During spaceflight, half of the mice were exposed to artificial earth gravity (1 g) using centrifugation cages. Sulfur-metabolomics of the livers of mice after spaceflight revealed a decrease in sulfur antioxidants (ergothioneine, glutathione, cysteine, taurine, thiamine, etc.) and their intermediates (cysteine sulfonic acid, hercynine, N-acethylserine, serine, etc.) compared to the controls on the ground. Furthermore, RNA-sequencing showed upregulation of gene sets related to oxidative stress and sulfur metabolism, and downregulation of gene sets related to glutathione reducibility in the livers of mice after spaceflight, compared to controls on the ground. These changes were partially mitigated by exposure to 1 g centrifugation. For the first time, we observed a decrease in sulfur antioxidants based on a comprehensive analysis of the livers of mice after spaceflight. Our data suggest that a decrease in sulfur-containing compounds owing to both microgravity and other spaceflight environments (radiation and stressors) contributes to liver damage after spaceflight.


Assuntos
Gravidade Alterada , Fígado/metabolismo , Voo Espacial , Enxofre/metabolismo , Animais , Perfilação da Expressão Gênica , Masculino , Redes e Vias Metabólicas , Metabolômica , Camundongos , Camundongos Endogâmicos C57BL , Ausência de Peso
5.
Int J Mol Sci ; 22(21)2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34769154

RESUMO

Humans have been committed to space exploration and to find the next planet suitable for human survival. The construction of an ecosystem that adapts to the long-term survival of human beings in space stations or other planets would be the first step. The space plant cultivation system is the key component of an ecosystem, which will produce food, fiber, edible oil and oxygen for future space inhabitants. Many plant experiments have been carried out under a stimulated or real environment of altered gravity, including at microgravity (0 g), Moon gravity (0.17 g) and Mars gravity (0.38 g). How plants sense gravity and change under stress environment of altered gravity were summarized in this review. However, many challenges remain regarding human missions to the Moon or Mars. Our group conducted the first plant experiment under real Moon gravity (0.17 g) in 2019. One of the cotton seeds successfully germinated and produced a green seedling, which represents the first green leaf produced by mankind on the Moon.


Assuntos
Gravitropismo , Plantas/metabolismo , Gravidade Alterada , Humanos , Fenômenos Fisiológicos Vegetais , Voo Espacial , Estresse Fisiológico
6.
Int J Mol Sci ; 22(19)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34638848

RESUMO

The space environment consists of a complex mixture of different types of ionizing radiation and altered gravity that represents a threat to humans during space missions. In particular, individual radiation sensitivity is strictly related to the risk of space radiation carcinogenesis. Therefore, in view of future missions to the Moon and Mars, there is an urgent need to estimate as accurately as possible the individual risk from space exposure to improve the safety of space exploration. In this review, we survey the combined effects from the two main physical components of the space environment, ionizing radiation and microgravity, to alter the genetics and epigenetics of human cells, considering both real and simulated space conditions. Data collected from studies on human cells are discussed for their potential use to estimate individual radiation carcinogenesis risk from space exposure.


Assuntos
Dano ao DNA , Genômica/métodos , Gravidade Alterada , Lesões por Radiação/genética , Simulação de Ausência de Peso/métodos , Ausência de Peso , Adaptação Fisiológica , Humanos , Proteção Radiológica/métodos , Voo Espacial/métodos
7.
Int J Mol Sci ; 22(17)2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34502336

RESUMO

The mechanisms underlying gravity perception in mammalian cells are unknown. We have recently discovered that the transcriptome of cells in the immune system, which is the most affected system during a spaceflight, responds rapidly and broadly to altered gravity. To pinpoint potential underlying mechanisms, we compared gene expression and three-dimensional (3D) chromosomal conformational changes in human Jurkat T cells during the short-term gravitational changes in parabolic flight and suborbital ballistic rocket flight experiments. We found that differential gene expression in gravity-responsive chromosomal regions, but not differentially regulated single genes, are highly conserved between different real altered gravity comparisons. These coupled gene expression effects in chromosomal regions could be explained by underlying chromatin structures. Based on a high-throughput chromatin conformation capture (Hi-C) analysis in altered gravity, we found that small chromosomes (chr16-22, with the exception of chr18) showed increased intra- and interchromosomal interactions in altered gravity, whereby large chromosomes showed decreased interactions. Finally, we detected a nonrandom overlap between Hi-C-identified chromosomal interacting regions and gravity-responsive chromosomal regions (GRCRs). We therefore demonstrate the first evidence that gravitational force-induced 3D chromosomal conformational changes are associated with rapid transcriptional response in human T cells. We propose a general model of cellular sensitivity to gravitational forces, where gravitational forces acting on the cellular membrane are rapidly and mechanically transduced through the cytoskeleton into the nucleus, moving chromosome territories to new conformation states and their genes into more expressive or repressive environments, finally resulting in region-specific differential gene expression.


Assuntos
Cromossomos Humanos/química , Regulação da Expressão Gênica , Gravidade Alterada/efeitos adversos , Linfócitos T/metabolismo , Transcriptoma , Humanos , Células Jurkat
8.
Cells ; 10(9)2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34571874

RESUMO

Gravity is fundamental factor determining all processes of development and vital activity on Earth. During evolution, a complex mechanism of response to gravity alterations was formed in multicellular organisms. It includes the "gravisensors" in extracellular and intracellular spaces. Inside the cells, the cytoskeleton molecules are the principal gravity-sensitive structures, and outside the cells these are extracellular matrix (ECM) components. The cooperation between the intracellular and extracellular compartments is implemented through specialized protein structures, integrins. The gravity-sensitive complex is a kind of molecular hub that coordinates the functions of various tissues and organs in the gravitational environment. The functioning of this system is of particular importance under extremal conditions, such as spaceflight microgravity. This review covers the current understanding of ECM and associated molecules as the matrisome, the features of the above components in connective tissues, and the role of the latter in the cell and tissue responses to the gravity alterations. Special attention is paid to contemporary methodological approaches to the matrisome composition analysis under real space flights and ground-based simulation of its effects on Earth.


Assuntos
Matriz Extracelular/fisiologia , Animais , Gravidade Alterada , Humanos , Voo Espacial/métodos , Ausência de Peso
9.
J Appl Physiol (1985) ; 131(2): 689-701, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34197228

RESUMO

This study investigated whether artificial gravity (AG), induced by short-radius centrifugation, mitigated deterioration in standing balance and anticipatory postural adjustments (APAs) of trunk muscles following 60-day head-down tilt bed rest. Twenty-four participants were allocated to one of three groups: control group (n = 8); 30-min continuous AG daily (n = 8); and intermittent 6 × 5 min AG daily (n = 8). Before and immediately after bed rest, standing balance was assessed in four conditions: eyes open and closed on both stable and foam surfaces. Measures including sway path, root mean square, and peak sway velocity, sway area, sway frequency power, and sway density curve were extracted from the center of pressure displacement. APAs were assessed during rapid arm movements using intramuscular or surface electromyography electrodes of the rectus abdominis; obliquus externus and internus abdominis; transversus abdominis; erector spinae at L1, L2, L3, and L4 vertebral levels; and deep lumbar multifidus muscles. The relative latency between the EMG onset of the deltoid and each of the trunk muscles was calculated. All three groups had poorer balance performance in most of the parameters (all P < 0.05) and delayed APAs of the trunk muscles following bed rest (all P < 0.05). Sway path and sway velocity were deteriorated, and sway frequency power was less in those who received intermittent AG than in the control group (all P < 0.05), particularly in conditions with reduced proprioceptive feedback. These data highlight the potential of intermittent AG to mitigate deterioration of some aspects of postural control induced by gravitational unloading, but no protective effects on trunk muscle responses were observed.NEW & NOTEWORTHY This study presents novel insights into the effect of artificial gravity (AG) on the deterioration of standing balance and anticipatory postural adjustments (APAs) of trunk muscles induced by 60-day strict head-down bed rest. The results indicated severe balance dysfunction and delayed APAs during rapid arm movement. AG partially mitigated the deterioration in standing balance and may thus be considered as a potential countermeasure for future planetary surface explorations. Optimization of AG protocols might enhance effects.


Assuntos
Repouso em Cama , Gravidade Alterada , Repouso em Cama/efeitos adversos , Centrifugação , Eletromiografia , Decúbito Inclinado com Rebaixamento da Cabeça , Humanos , Músculo Esquelético , Músculos Paraespinais , Equilíbrio Postural
10.
J Appl Physiol (1985) ; 131(1): 356-368, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34080918

RESUMO

Exposure to axial unloading induces adaptations in paraspinal muscles, as shown after spaceflights. This study investigated whether daily exposure to artificial gravity (AG) mitigated lumbar spine flattening and muscle atrophy associated with 60-day head-down tilt (HDT) bed rest (Earth-based space analog). Twenty-four healthy individuals participated in the study: 8 received 30-min continuous AG; 8 received 6 × 5-min AG interspersed with rest periods; and 8 received no AG exposure (control group). Magnetic resonance imaging (MRI) of the lumbopelvic region was conducted at baseline (BDC) and at day 59 of HDT (HDT59). Longitudinal relaxation time (T1)-weighted images were used to assess morphology of the lumbar spine (spinal length, intervertebral disk angles, disk area) and volumes of the lumbar multifidus (LM), lumbar erector spinae (LES), quadratus lumborum (QL), and psoas major (PM) muscles from L1/L2 to L5/S1 vertebral levels. A chemical shift-based two-point lipid/water Dixon sequence was used to evaluate muscle composition. Results showed that spinal length and disk area increased (P < 0.05); intervertebral disk angles (P < 0.05) and muscle volumes of LM, LES, and QL reduced (P < 0.01); and lipid-to-water ratio for the LM and LES muscles increased (P < 0.01) after HDT59 in all groups. Neither of the AG protocols mitigated the lumbar spinae deconditioning induced by HDT bed rest. The increase in lipid-to-water ratio in LM and LES muscles indicates an increased relative intramuscular lipid concentration. Altered muscle composition in atrophied muscles may impair lumbar spine function after body unloading, which could increase injury risk to vulnerable soft tissues. This relationship needs further investigation.NEW & NOTEWORTHY This study presents novel insights into the morphological adaptations occurring in the lumbar spine after 60-day head-down bed rest and the potential role of artificial gravity (AG) to mitigate them. Results demonstrated no protective effect of AG protocols used in this study. In atrophied paraspinal muscles, the ratio of lipids versus intramuscular water increased in the postural lumbar muscles, which could impair muscle function during upright standing. These findings have relevance for future space explorations.


Assuntos
Repouso em Cama , Gravidade Alterada , Repouso em Cama/efeitos adversos , Decúbito Inclinado com Rebaixamento da Cabeça , Humanos , Vértebras Lombares/diagnóstico por imagem , Região Lombossacral , Imageamento por Ressonância Magnética , Atrofia Muscular/etiologia
11.
J Biomed Mater Res A ; 109(11): 2322-2333, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33960131

RESUMO

Gravity alterations elicit complex and mostly detrimental effects on biological systems. Among these, a prominent role is occupied by oxidative stress, with consequences for tissue homeostasis and development. Studies in altered gravity are relevant for both Earth and space biomedicine, but their implementation using whole organisms is often troublesome. Here we utilize planarians, simple worm model for stem cell and regeneration biology, to characterize the pathogenic mechanisms brought by artificial gravity alterations. In particular, we provide a comprehensive evaluation of molecular responses in intact and regenerating specimens, and demonstrate a protective action from the space-apt for nanotechnological antioxidant cerium oxide nanoparticles.


Assuntos
Cério , Gravidade Alterada , Nanopartículas/química , Planárias/metabolismo , Regeneração/efeitos dos fármacos , Animais , Cério/química , Cério/farmacologia
12.
Vestn Oftalmol ; 137(2): 26-33, 2021.
Artigo em Russo | MEDLINE | ID: mdl-33881260

RESUMO

The active exploration of space requires minimizing negative effects induced by weightlessness (microgravity). Risk reduction can be achieved with the use of artificial gravity created by short-radius centrifuge (SRC). Short-radius centrifuge causes redistribution of body liquids towards the caudal portion of the body imitating a vertical human pose. Presently, studying the safety of this prevention method for the human body in general, and for the visual system in particular, is one of the priority tasks of space medicine. PURPOSE: To study the effects of artificial gravity on the perimetry measurements of the eye. MATERIAL AND METHODS: The study included 9 volunteers (men) aged 31.2±6 years (from 25 to 40 years). Each man was subjected to three rotations on SRC. The operative factor in the tests was overloads in the «head-pelvis¼ direction. Rotations were carried out in three different modes with varying maximum overload value at the feet level of up to 2.0; 2.4; 2.9 G. Pulsar-perimetry was carried out before and 1-2 hours after the rotations estimating the mean threshold of retinal photosensitivity Mean Sensitivity (MS), mean loss of sensitivity Mean Defect (MD), square root of Loss Variance (sLV); the Bebie curve; additionally, cluster analysis was performed. RESULTS: Mean threshold of retinal photosensitivity, mean loss of photosensitivity, square root of Loss Variance by Pulsar-perimetry before (MS=22.75 dB; MD= -0.6 dB; sLV=1.5) and after rotations on SRC (in Mode 1: 23.4; -0.2; 1.5, Mode 2: 23.2; -0.4; 1.4 and Mode 3: 23.5; -0.8; 1.4 respectively) did not change significantly. No adverse phenomena were detected in the eyes. CONCLUSIONS: There were no significant changes in the visual fields of the test subjects after rotations in three different modes according to Pulsar-perimetry data, which gives reason to tentatively conclude that using SCR in these modes is safe for the visual sensory system. According to preliminary data, this method can be successfully used to reduce the risk of long-term space flights and prevent unwanted phenomena caused by weightlessness.


Assuntos
Gravidade Alterada , Testes de Campo Visual , Adulto , Olho , Humanos , Masculino , Sensibilidade e Especificidade , Campos Visuais
13.
Eur J Appl Physiol ; 121(7): 2015-2026, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33811556

RESUMO

PURPOSE: Spaceflight impairs physical capacity. Here we assessed the protective effect of artificial gravity (AG) on aerobic exercise capacity and muscle function during bed rest, a spaceflight analogue. METHODS: 24 participants (33 ± 9 years, 175 ± 9 cm, 74 ± 10 kg, 8 women) were randomly allocated to one of three groups: continuous AG (cAG), intermittent AG (iAG) or control (CTRL). All participants were subjected to 60 days of six-degree head-down tilt bed rest, and subjects of the intervention groups completed 30 min of centrifugation per day: cAG continuously and iAG for 6 × 5 min, with an acceleration of 1g at the center of mass. Physical capacity was assessed before and after bed rest via maximal voluntary contractions, cycling spiroergometry, and countermovement jumps. RESULTS: AG had no significant effect on aerobic exercise capacity, flexor muscle function and isometric knee extension strength or rate of force development (RFD). However, AG mitigated the effects of bed rest on jumping power (group * time interaction of the rmANOVA p < 0.001; iAG - 25%, cAG - 26%, CTRL - 33%), plantar flexion strength (group * time p = 0.003; iAG - 35%, cAG - 31%, CTRL - 48%) and plantar flexion RFD (group * time p = 0.020; iAG - 28%, cAG - 12%, CTRL - 40%). Women showed more pronounced losses than men in jumping power (p < 0.001) and knee extension strength (p = 0.010). CONCLUSION: The AG protocols were not suitable to maintain aerobic exercise capacity, probably due to the very low cardiorespiratory demand of this intervention. However, they mitigated some losses in muscle function, potentially due to the low-intensity muscle contractions during centrifugation used to avoid presyncope.


Assuntos
Repouso em Cama , Tolerância ao Exercício/fisiologia , Gravidade Alterada , Adulto , Ergometria , Feminino , Decúbito Inclinado com Rebaixamento da Cabeça , Humanos , Masculino , Contração Muscular/fisiologia , Fatores de Tempo
14.
Comput Methods Biomech Biomed Engin ; 24(14): 1578-1587, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33724105

RESUMO

Aviation medical research shows that disuse osteoporosis will occur after long-term space flight. Even with countermeasures such as exercise and drug treatments, this outcome cannot be avoided in flight. In recent years, the application of artificial gravity devices that change the mechanical microenvironment of bone in microgravity have shown promise in mitigating the risk of disuse osteoporosis. Considering the existence of osteocytes, a fluid-solid coupling finite element model for osteons with two-stage pore structure (Haversian canal, lacunar-canalicular system) was established. In order to study the changes in the mechanical behavior of osteocytes under the action of various artificial gravity (AG) devices, including long-arm centrifuge (LAC), short-arm centrifuge (SAC), and a lower body negative pressure (LBNP) chamber. In addition, the difference in pulsating pressure and static pressure stress caused by the gravity gradient under the AG devices was examined. The simulation results showed that the AG devices could effectively improve the stress level of osteocytes in microgravity. The mechanical microenvironment of osteocytes that was provided by the LAC was closest to that of the Earth's gravitational field. The mechanical stimulation on osteocytes was not significantly improved by the SAC, but from a practical viewpoint, it occupied less space than the LAC. The LBNP chamber created a higher level of stress for osteocytes. Therefore, the LAC was an ideal device for replacing Earth's gravitational field, except for the practical limitations of its physical size. In contrast, the LBNP device had the greatest application potential in training for its expansibility and convenience.


Assuntos
Gravidade Alterada , Ausência de Peso , Simulação por Computador , Ósteon , Osteócitos
15.
Exp Cell Res ; 399(2): 112463, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33385417

RESUMO

Artificial gravity is a potential countermeasure to attenuate effects of weightlessness during long-term spaceflight, including losses of muscle mass and function, possibly to some extent attributable to disturbed neuromuscular interaction. The 60-day AGBRESA bed-rest study was conducted with 24 participants (16 men, 8 women; 33 ± 9 years; 175 ± 9 cm; 74 ± 10 kg; 8 control group, 8 continuous (cAG) and 8 intermittent (iAG) centrifugation) to assess the impact of bed rest with or without daily 30-min continuous/intermittent centrifugation with 1G at the centre of mass. Fasting blood samples were collected before and on day 6, 20, 40 and 57 during 6° head-down tilt bed rest. Concentrations of circulating markers of muscle wasting (GDF-8/myostatin; slow skeletal muscle troponin T; prostaglandin E2), neurotrophic factors (BDNF; GDNF) and C-terminal Agrin Fragment (CAF) were determined by ELISAs. Creatine kinase activity was assessed by colorimetric enzyme assay. Repeated-measures ANOVAs were conducted with TIME as within-subject, and INTERVENTION and SEX as between-subject factors. The analyses revealed no significant effect of bed rest or sex on any of the parameters. Continuous or intermittent artificial gravity is a safe intervention that does not have a negative impact of the neuromuscular secretome.


Assuntos
Repouso em Cama , Gravidade Alterada , Decúbito Inclinado com Rebaixamento da Cabeça/fisiologia , Músculo Esquelético/metabolismo , Proteoma/metabolismo , Adulto , Repouso em Cama/efeitos adversos , Estudos de Casos e Controles , Feminino , Gravidade Alterada/efeitos adversos , Decúbito Inclinado com Rebaixamento da Cabeça/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/inervação , Atrofia Muscular/etiologia , Atrofia Muscular/metabolismo , Fenômenos Fisiológicos do Sistema Nervoso , Via Secretória , Fatores de Tempo , Adulto Jovem
16.
Am J Med ; 134(3): e181-e183, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33115615

RESUMO

BACKGROUND: Asymptomatic mastoid effusions have recently been observed in astronauts returning from long-term spaceflight. In hospitalized patients, mastoid effusion increases the risks for bacterial otitis and mastoiditis. We reasoned that cephalad fluid shifts during strict -6° head down tilt bed rest could reproduce space-flight associated mastoid effusion and that artificial gravity may reverse the response. METHODS: The recent Artificial Gravity Bed Rest Study-European Space Agency study (AGBRESA) tested influences of artificial gravity during 60 days head down bed rest on a short-arm human centrifuge in healthy participants. The two intervention groups received daily artificial gravity with 30 minutes continuous artificial gravity or intermittent artificial gravity. A third group served as a control group and received no artificial gravity. We assessed cranial magnetic resonance images for mastoid effusions 1 day before bed rest, at days 14 and 52 of bed rest, and 3 days after bed rest. RESULTS: None of the participants exhibited mastoid effusions before bed rest. Six participants showed mastoid effusions at bed rest day 14 (4 continuous, 2 intermittent, 0 control). Fifteen participants showed mastoid effusions at bed rest day 52 and 3 days after bed rest (7 continuous, 3 intermittent, 5 control). CONCLUSIONS: Mastoid effusions commonly occur during strict head down tilt bed rest. The model can be applied to study the mechanisms and potential countermeasures for space flight-associated mastoid effusions. Formation of mastoid effusions during head down tilt bed rest is not prevented by daily 30 minutes short-arm intermittent or continuous centrifugation.


Assuntos
Repouso em Cama , Líquidos Corporais , Gravidade Alterada , Decúbito Inclinado com Rebaixamento da Cabeça , Processo Mastoide , Adulto , Feminino , Decúbito Inclinado com Rebaixamento da Cabeça/efeitos adversos , Humanos , Masculino
17.
ESC Heart Fail ; 8(1): 729-744, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33191629

RESUMO

AIMS: Reduced physical activity increases the risk of heart failure; however, non-invasive methodologies detecting subclinical changes in myocardial function are not available. We hypothesized that myocardial, left ventricular, systolic strain measurements could capture subtle abnormalities in myocardial function secondary to physical inactivity. METHODS AND RESULTS: In the AGBRESA study, which assessed artificial gravity through centrifugation as potential countermeasure for space travel, 24 healthy persons (eight women) were submitted to 60 day strict -6° head-down-tilt bed rest. Participants were assigned to three groups of eight subjects: a control group, continuous artificial gravity training on a short-arm centrifuge (30 min/day), or intermittent centrifugation (6 × 5 min/day). We assessed cardiac morphology, function, strain, and haemodynamics by cardiac magnetic resonance imaging (MRI) and echocardiography. We observed no differences between groups and, therefore, conducted a pooled analysis. Consistent with deconditioning, resting heart rate (∆8.3 ± 6.3 b.p.m., P < 0.0001), orthostatic heart rate responses (∆22.8 ± 19.7 b.p.m., P < 0.0001), and diastolic blood pressure (∆8.8 ± 6.6 mmHg, P < 0.0001) increased, whereas cardiac output (∆-0.56 ± 0.94 L/min, P = 0.0096) decreased during bed rest. Left ventricular mass index obtained by MRI did not change. Echocardiographic left ventricular, systolic, global longitudinal strain (∆1.8 ± 1.83%, P < 0.0001) decreased, whereas left ventricular, systolic, global MRI circumferential strain increased not significantly (∆-0.68 ± 1.85%, P = 0.0843). MRI values rapidly returned to baseline during recovery. CONCLUSION: Prolonged head-down-tilt bed rest provokes changes in cardiac function, particularly strain measurements, that appear functional rather than mediated through cardiac remodelling. Thus, strain measurements are of limited utility in assessing influences of physical deconditioning or exercise interventions on cardiac function.


Assuntos
Repouso em Cama , Gravidade Alterada , Pressão Sanguínea , Feminino , Decúbito Inclinado com Rebaixamento da Cabeça , Coração , Humanos
18.
Rev Neurol ; 71(12): 447-454, 2020 Dec 16.
Artigo em Espanhol, Inglês | MEDLINE | ID: mdl-33319347

RESUMO

INTRODUCTION: Treadmill training is considered an effective intervention to improve gait ability in patients with Parkinson's disease (PD). In parallel, virtual reality shows promising intervention with several applications in the inpatient medical setting. AIM: To evaluate the feasibility and preliminary efficacy of mechanical gait assistance combined with immersive virtual reality in patients with PD. PATIENTS AND METHODS: This pilot and feasibility study followed a pre-post study design. The intervention consisted of 12 sessions of 30 minutes, distributed regularly over four consecutive weeks. Participants walked on a treadmill with a body-weight support system set at approximately 20% of body weight and equipped with a virtual reality helmet controlled by a two-handed joystick. Feasibility and intervention outcomes were collected at baseline and after four weeks of intervention. RESULTS: Twelve participants of 60 patients were finally enrolled. Nine of them (75%) completed the treatment intervention with an adherence rate of 97%. Two participants left the study, one of them due to sickness associated with virtual reality and another because of a lack of motivation. There were significant differences associated with small-medium effect sizes when comparing the pre and post values for walk distance, walk speed, balance, and quality of life. CONCLUSIONS: The present study provided preliminary evidence supporting the feasibility of the combination of antigravity treadmill and immersive virtual reality system for the rehabilitation of patients with PD.


TITLE: Entrenamiento antigravitatorio e inmersivo de realidad virtual para la rehabilitación de la marcha en la enfermedad de Parkinson: estudio piloto y de viabilidad.Introducción. El entrenamiento en tapiz rodante se considera una intervención eficaz para mejorar la capacidad de la marcha en pacientes con enfermedad de Parkinson (EP). Paralelamente, la realidad virtual se muestra como una intervención prometedora con diversas aplicaciones en el entorno médico hospitalario. Objetivo. Evaluar la viabilidad y la eficacia preliminar de la asistencia mecánica para la marcha combinada con la realidad virtual inmersiva en pacientes con EP. Pacientes y métodos. Este estudio piloto y de viabilidad siguió un diseño pre-post. La intervención consistió en 12 sesiones de 30 minutos, distribuidas regularmente durante cuatro semanas consecutivas. Los participantes deambularon sobre un tapiz rodante con un sistema de descarga del peso corporal establecido aproximadamente en el 20% del peso corporal y equipados con un casco de realidad virtual controlado por un joystick para cada mano. Las mediciones de viabilidad y tratamiento se recopilaron al inicio del estudio y después de cuatro semanas de intervención. Resultados. De un total de 60 pacientes, se reclutó finalmente a 12 participantes. Nueve de ellos (75%) completaron el tratamiento, con una tasa de adhesión del 97%. Dos participantes abandonaron el estudio, uno debido a náuseas asociadas con la realidad virtual y otro por falta de motivación. Hubo diferencias significativas asociadas con un tamaño del efecto pequeño-mediano al comparar los valores pre y post para la distancia recorrida, velocidad de la marcha, equilibrio y calidad de vida. Conclusiones. El estudio proporcionó evidencia preliminar que apoya la viabilidad de la combinación de un tapiz rodante antigravitatorio y un sistema de realidad virtual inmersivo para la rehabilitación de pacientes con EP.


Assuntos
Terapia por Exercício , Estudos de Viabilidade , Transtornos Neurológicos da Marcha/reabilitação , Doença de Parkinson/reabilitação , Projetos Piloto , Terapia de Exposição à Realidade Virtual , Idoso , Simulação por Computador , Terapia por Exercício/instrumentação , Terapia por Exercício/métodos , Feminino , Transtornos Neurológicos da Marcha/fisiopatologia , Gravidade Alterada , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/fisiopatologia , Equilíbrio Postural , Terapia de Exposição à Realidade Virtual/instrumentação , Terapia de Exposição à Realidade Virtual/métodos , Caminhada
19.
PLoS One ; 15(9): e0239228, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32946482

RESUMO

Artificial gravity through short-arm centrifugation has potential as a multi-system countermeasure for deconditioning and cranial fluid shifts that may underlie ocular issues in microgravity. However, the optimal short-arm centrifugation protocol that is effective whilst remaining tolerable has yet to be determined. Given that exposure to centrifugation is associated with presyncope and syncope and in addition motion sickness an intermittent protocol has been suggested to be more tolerable. Therefore, we assessed cardiovascular loading and subjective tolerability of daily short arm centrifugation with either an intermittent or a continuous protocol during long-term head-down bed rest as model for microgravity exposure in a mixed sex cohort. During the Artificial Gravity Bed Rest with European Space Agency (AGBRESA) 60 day 6° head down tilt bed rest study we compared the tolerability of daily +1 Gz exposure at the center of mass centrifugation, either performed continuously for 30 minutes, or intermittedly (6 x 5 minutes). Heart rate and blood pressure were assessed daily during centrifugation along with post motion sickness scoring and rate of perceived exertion. During bed rest, 16 subjects (6 women, 10 men), underwent 960 centrifuge runs in total. Ten centrifuge runs had to be terminated prematurely, 8 continuous runs and 2 intermittent runs, mostly due to pre-syncopal symptoms and not motion sickness. All subjects were, however, able to resume centrifuge training on subsequent days. We conclude that both continuous and intermittent short-arm centrifugation protocols providing artificial gravity equivalent to +1 Gz at the center of mass is tolerable in terms of cardiovascular loading and motion sickness during long-term head down tilt bed rest. However, intermittent centrifugation appears marginally better tolerated, albeit differences appear minor.


Assuntos
Centrifugação , Gravidade Alterada/efeitos adversos , Enjoo devido ao Movimento , Repouso em Cama , Pressão Sanguínea , Estudos de Coortes , Feminino , Decúbito Inclinado com Rebaixamento da Cabeça , Voluntários Saudáveis , Frequência Cardíaca , Humanos , Masculino
20.
J Physiol ; 598(19): 4237-4249, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32715482

RESUMO

KEY POINTS: The aim of this study was to determine the effect of rotational axis position (RAP and thus g-gradient) during short-arm human centrifugation (SAHC) upon cardiovascular responses, cerebral perfusion and g-tolerance. In 10 male and 10 female participants, 10 min passive SAHC runs were performed with the RAP above the head (P1), at the apex of the head (P2), or at heart level (P3), with foot-level Gz at 1.0 g, 1.7 g and 2.4 g. We hypothesized that movement of the RAP from above the head (the conventional position) towards the heart might reduce central hypovolaemia, limit cardiovascular responses, aid cerebral perfusion, and thus promote g-tolerance. Moving the RAP footward towards the heart decreased the cerebral tissue saturation index, calf circumference and heart rate responses to SAHC, thereby promoting g-tolerance. Our results also suggest that RAP, and thus g-gradient, warrants further investigation as it may support use as a holistic spaceflight countermeasure. ABSTRACT: Artificial gravity (AG) through short-arm human centrifugation (SAHC) has been proposed as a holistic spaceflight countermeasure. Movement of the rotational axis position (RAP) from above the head towards the heart may reduce central hypovolaemia, aid cerebral perfusion, and thus promote g-tolerance. This study determined the effect of RAP upon cardiovascular responses, peripheral blood displacement (i.e. central hypovolaemia), cerebral perfusion and g-tolerance, and their inter-relationships. Twenty (10 male) healthy participants (26.2 ± 4.0 years) underwent nine (following a familiarization run) randomized 10 min passive SAHC runs with RAP set above the head (P1), at the apex of the head (P2), or at heart level (P3) with foot-level Gz at 1.0 g, 1.7 g and 2.4 g. Cerebral tissue saturation index (cTSI, cerebral perfusion surrogate), calf circumference (CC, central hypovolaemia), heart rate (HR) and digital heart-level mean arterial blood pressure (MAP) were continuously recorded, in addition to incidence of pre-syncopal symptoms (PSS). ΔCC and ΔHR increases were attenuated from P1 to P3 (ΔCC: 5.46 ± 0.54 mm to 2.23 ± 0.42 mm; ΔHR: 50 ± 4 bpm to 8 ± 2 bpm, P < 0.05). In addition, ΔcTSI decrements were also attenuated (ΔcTSI: -2.85 ± 0.48% to -0.95 ± 0.34%, P < 0.05) and PSS incidence lower in P3 than P1 (P < 0.05). A positive linear relationship was observed between ΔCC and ΔHR with increasing +Gz, and a negative relationship between ΔCC and ΔcTSI, both independent of RAP. Our data suggest that movement of RAP towards the heart (reduced g-gradient), independent of foot-level Gz, leads to improved g-tolerance. Further investigations are required to assess the effect of differential baroreceptor feedback (i.e. aortic-carotid g-gradient).


Assuntos
Gravidade Alterada , Pressão Sanguínea , Centrifugação , Circulação Cerebrovascular , Feminino , Gravitação , Frequência Cardíaca , Humanos , Masculino
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