npj Microgravity最新文献

Contemporary plans to establish human habitation on the Earth's Moon have increased interest in the ability of humans to establish extraterrestrial pregnancies. There is a lack of data to identify if humans could safely reproduce away from the Earth, and even less guidance with regard to whether we should attempt to do so. This work was developed to stimulate investigation into the likely biological and ethical challenges facing the establishment and maintenance of a healthy human extraterrestrial pregnancy.

Spaceflight Standard Measures is an integrated research study designed to characterize how spaceflight affects the health and performance of astronauts. Standardizing the research methods allows for robust monitoring of individuals and allows comparison between crewmembers of different missions of various durations. This manuscript reviews the objectives of the Spaceflight Standard Measures project, and details how each disciplinary component is used to monitor spaceflight-induced human risks. It also covers the timeline of data collection, the methods used to analyze the data, and the process for requesting access to the data. With the impending return to lunar operations and exploration of deep space, an urgent need exists for high-quality, multidisciplinary investigations to inform programmatic and operational decisions. The Spaceflight Standard Measures model provides a standardized, flexible research approach, fostering collaboration across agencies to create a strong evidence base that can be used to safely advance human spaceflight into multiplanetary exploration.

Microgravity exposure induces cardiac deconditioning, primarily due to hypovolemia and inactivity. Animal models suggest microgravity may cause left ventricular (LV) papillary muscle atrophy, but this has not been studied in humans. This study used MRI to assess LV papillary muscle mass and LV morphology and function in nine male cosmonauts before and 6 ± 2 days after long-duration spaceflight (247 ± 90 days). Spaceflight did not affect LV volumes, ejection fraction, and strain parameters, but increased heart rate (P < 0.001) and cardiac output (P = 0.03). LV papillary muscle mass decreased by 14% (P = 0.017), while LV mass tended to increase (P = 0.083), mitral annular diameter increased (P = 0.004) without mitral leakage, and LV sphericity increased (P = 0.02). These findings suggest LV adapts to space with geometric changes, but microgravity-induced papillary muscle atrophy requires further study for long-term implications.

Microgravity induces cardiovascular adaptations, including fluid shifts, cardiac remodeling, and autonomic changes. Acute responses involve increased preload and stroke volume, while chronic adaptations include cardiac atrophy, vascular remodeling, and autonomic impairment, contributing to post-flight orthostatic intolerance. These changes raise concerns for long-term astronaut health. Understanding these adaptations is crucial for developing countermeasures to mitigate spaceflight-related cardiovascular risks and may offer insights applicable to terrestrial medicine.

Spaceflight studies present novel insights into biological processes through exposure to stressors outside the evolutionary path of terrestrial organisms. Despite limited access to space environments, numerous transcriptomic datasets from spaceflight experiments are now available through NASA's GeneLab data repository, which allows public access, encouraging further analysis. While various computational pipelines and methods have been used to process these transcriptomic datasets, learning-model-driven analyses have yet to be applied to a broad array of such spaceflight-related datasets. In this study, we present an open-source pipeline, GLARE: GeneLAb Representation learning pipelinE, which consists of training different representation learning approaches from manifold learning to self-supervised learning that enhance the performance of downstream analytical tasks. We illustrate the utility of GLARE by applying it to gene-level transcriptional values from the results of the CARA spaceflight experiment, an Arabidopsis root tip transcriptome dataset that spanned light, dark, and microgravity treatments. We show that GLARE not only substantiated the findings of the original study concerning cell wall remodeling but also revealed additional patterns of gene expression affected by the treatments, including evidence of hypoxic response. This work suggests there is great potential to supplement the insights drawn from initial studies on spaceflight omics-level data through further machine-learning-enabled analyses.

Astronauts on long-duration space missions may benefit nutritionally and psychologically from growing and consuming fresh fruits and vegetables. Gardening and exposure to nature can improve mood, reduce stress, provide meaningful and enjoyable tasks, and provide sensory stimulation. We investigated the behavioral health benefits of farming in space. Twenty-seven long-duration astronauts on the International Space Station engaged in crop growth experiments and answered surveys about their experiences, reactions to farming, and consumption of fresh fruits and vegetables throughout their missions. Findings indicate generally positive responses such that astronauts found the crop growth tasks enjoyable, engaging, meaningful, and stimulating. Ratings of behavioral health outcomes were consistent over time, while perceived sensory stimulation enjoyment increased over time. Positive effects were stronger when astronauts engaged in the most enjoyable tasks (i.e., consuming and voluntary viewing of plants). We discuss the implications of farming in space as a resilience countermeasure in austere environments.

Study investigated if abdominal low-intensity pulsed ultrasound (LIPUS) alleviates simulated microgravity (hindlimb unloading, HU)-induced skeletal muscle atrophy by restoring gut microbiota. Mice were divided into control (NC), HU, and HU with daily abdominal LIPUS (HU + LIPUS) groups. Fecal microbiota transplantation (FMT) from LIPUS-treated mice to HU mice was also performed. After 28 days, abdominal LIPUS partially reversed HU-induced gut dysbiosis, restored intestinal barrier integrity, and increased short-chain fatty acid (SCFAs) levels. LIPUS downregulated muscle atrophy genes (MSTN, ActRIIB) and upregulated growth genes (Akt, mTOR) in HU mice, preventing muscle loss. SCFAs levels positively correlated with muscle function. HU mice receiving FMT from LIPUS-treated donors showed similar gut and muscle improvements as direct LIPUS treatment. Results demonstrate abdominal LIPUS ameliorates muscle atrophy by modulating the gut-muscle axis, offering a potential non-invasive strategy for astronauts and patients.

Long-duration spaceflight affects otolith-mediated ocular counter-roll (OCR) and brain function, but the relationship between these changes is unclear. This study examines whether OCR changes correlate with functional connectivity (FC) changes in the vestibular network in the same cosmonauts after a long-duration (6-month) spaceflight mission. Using a human vestibular atlas, we found that changes in FC between the right operculum (OP2_PIVC) and inferior parietal lobule (IPL, area PGp and PGa) were positively correlated with OCR changes. First-time flyers showed a greater decrease in OCR, linked to more significant FC reductions. Irrespective of the OCR, increased FC was observed postflight between the left visual cingulate cortex (CSv) and the anterior cingulate cortex (ACC, area 33), superior parietal lobule (SPL, area 5C), and thalamus (pulvinar), and between the right OP2_PIVC and SPL (area 5Ci). Secondly, decreased FC was observed between the left OP2_PIVC and the IPL (PGp) and SPL (area 7A). Additionally, increased FC postflight was observed between the left lateral sensorimotor area (LSM) and IPL (area PGp), and between the right lateral visual area (LVA) and cerebellum (Crus 1, Lobule VI). These findings suggest sensory reweighting and sensory system reorganization after long-duration spaceflight.

This study aimed to investigate cervical vessel hemodynamics during 7 days of -6° head-down tilt (HDT) bed rest (BR) and 5 days of recovery in 40 healthy males, focusing on bilateral analysis and dynamic temporal monitoring. Diameter, flow velocity, and blood flow volume (BFV) of bilateral common (CCAs), internal (ICAs), external carotid arteries and vertebral arteries (VAs) were measured at eight time points using ultrasound. Cervical vessels exhibited heterogeneous and lateralized responses. Left VA exhibited the most pronounced BFV and velocity fluctuations, with significant reductions during HDT and recovery to baseline post-HDT, while right VA remained stable. CCAs and ICAs had dynamic diameter and velocity changes, but stable BFVs. Left VA BFV reduction was significantly associated with right VA dominance, elevated heart rate, and increased mean arterial pressure at HDT 3 d. Despite stable total BFV, left VA BFV declined during BR, warranting further monitoring.