Review animal model studies, rodent experiments, and biological research using various species in spaceflight conditions.
A study on the ISS reveals that lunar gravity (1/6 g) partially mitigates the severe bone loss and immune system atrophy caused by microgravity. However, it is not sufficient to fully protect against these adverse health effects, providing critical data for astronaut health during future Artemis missions.
Researchers successfully transferred stress-tolerant proteins (CAHS) from extremophile tardigrades into human cells. The engineered cells showed increased resilience to hyperosmotic stress, a proxy for dehydration, suggesting a powerful new biotechnology for protecting biological materials during space missions.
A study on mice exposed to simulated galactic cosmic rays (GCR) reveals long-term changes in heart and plasma proteins 8 months post-exposure. A key finding is the activation of pathways leading to Neutrophil Extracellular Traps (NETs) in heart tissue, a process linked to inflammation, tissue damage, and thrombosis, highlighting a significant cardiovascular risk for long-duration space missions.
Genomic analysis of tardigrades reveals their legendary resilience to extreme environments is not from a single source, but a complex mosaic of ancient, vertically inherited genes and key DNA repair proteins acquired from bacteria via horizontal gene transfer. This nuanced view of extremotolerance evolution provides critical insights for astrobiology and biotechnology.
This comprehensive review synthesizes evidence on the multi-organ, systemic effects of SARS-CoV-2 infection, detailing how the virus disrupts whole-body metabolism, dysregulates the immune and endocrine systems, and leads to widespread organ damage. These findings are crucial for understanding both acute COVID-19 and its long-term sequelae (PASC), with implications for managing astronaut health during space missions.
Transcriptomic analysis of mice after 37 days in space reveals a strong correlation between impaired lipid metabolism in the liver and gene expression patterns of muscle atrophy. This suggests a systemic, starvation-like metabolic shift, highlighting the liver's role in driving muscle loss and pointing to dietary interventions as a potential countermeasure.
This study demonstrates that desiccation significantly increases harmful reactive oxygen species (ROS) in tardigrades. Using RNA interference, researchers identified that the antioxidant enzyme glutathione peroxidase is essential for survival, while other enzymes and aquaporin proteins are crucial for successful rehydration, highlighting a complex, synergistic defense mechanism.
Using a hindlimb unloading mouse model to simulate microgravity, researchers found significant changes in gene expression within cortical bone after just 7 days. The study highlights the upregulation of genes involved in cellular metabolism, such as Pfkfb3 and Mss51, identifying novel pathways that could be targeted to prevent bone loss during spaceflight.
Fruit flies born and raised on the ISS showed significant cardiac dysfunction, including reduced contractility and output. This study reveals that microgravity triggers extensive cardiac remodeling, downregulates structural genes, and dramatically upregulates genes for protein degradation, indicating a state of 'proteostatic stress' that may be a fundamental response of heart muscle to spaceflight.
This meta-analysis of 25 NASA GeneLab datasets reveals how biological systems respond to a wide range of space radiation doses. Key findings show dose-dependent activation of mitochondrial pathways and suppression of ribosomal and cardiac function pathways, providing critical insights for assessing astronaut health risks on long-duration missions.
A comprehensive analysis of liver tissue from mice on multiple space missions reveals that spaceflight consistently disrupts lipid metabolism. These changes, driven by key regulators like HNF4α and PPARα, resemble the early stages of non-alcoholic fatty liver disease (NAFLD), highlighting a potential health risk for long-duration space travel.
Multi-mission analysis of mice flown on the ISS reveals that spaceflight alone, independent of re-entry stress, causes significant lipid accumulation in the liver. This dysregulation, confirmed through transcriptomics and proteomics, points to early signs of non-alcoholic fatty liver disease (NAFLD), highlighting a potential health risk for astronauts on long-duration missions.
An ex vivo study on mouse vertebrae reveals that high-dose ionizing radiation (≥5,000 Gy) significantly reduces bone strength and fatigue life by causing collagen fragmentation. Increased collagen crosslinking, observed even at low doses, did not correlate with mechanical weakness, clarifying a key mechanism of radiation damage to bone.
Researchers developed a novel method combining 3D-printing, micro-CT imaging, and computational modeling to test mouse vertebrae with unprecedented precision. The technique reduces variability in fatigue life measurements by up to 5-fold, enhancing the ability to detect subtle bone quality changes in studies with limited samples, such as spaceflight experiments.
A study using centrifugation to create hypergravity reveals that the vestibular system's gravity sensors first become hypersensitive, then hyposensitive over time. This complex, time-dependent adaptation challenges existing theories and provides a new framework for understanding astronaut disorientation.
This study provides a detailed anatomical and synaptic map of the toadfish utricle, the primary gravity-sensing organ. It reveals distinct sensory zones and highly specific neural wiring, establishing a critical baseline for understanding how the vestibular system adapts to microgravity, a key factor in astronaut health and performance.
A 30-day spaceflight study on land snails revealed significant neural plasticity in the gravity-sensing system. Post-flight snails exhibited behavioral changes and neural hypersensitivity to tilt, with readaptation to Earth's gravity occurring within ~20 hours, providing a key model for understanding astronaut vestibular adaptation.
A ground-based study in mice reveals that high-dose (200 cGy) heavy-ion (⁵⁶Fe) radiation causes significant, long-term bone loss and severely impairs the bone-forming potential of marrow cells for up to a year. This highlights a critical dose threshold and suggests simple antioxidant countermeasures may be insufficient against galactic cosmic rays.
A study in mice demonstrates that a soluble BMPR1A fusion protein not only prevents bone loss from disuse but actively increases bone mass and strength. The treatment works by simultaneously boosting bone formation and reducing bone resorption, offering a promising new countermeasure for astronaut skeletal health on long-duration missions.
Following criticism of their initial claim of extensive horizontal gene transfer (HGT) in tardigrades, the authors re-analyzed multiple independent genome assemblies. They conclude that while the level of HGT is lower than first reported, it remains substantially elevated (3-7%) compared to other animals, suggesting HGT is a real and significant feature of the tardigrade genome.
A 2015 genomic analysis of the tardigrade *Hypsibius dujardini* initially proposed that nearly 17.5% of its genes were acquired from other organisms through horizontal gene transfer (HGT), suggesting a novel mechanism for its extreme resilience. This landmark finding proved highly controversial and was later largely attributed by the scientific community to unaccounted-for bacterial contamination, sparking a critical debate on genomic analysis methods.
This study details the successful training and selection program for group-housed male mice for the 30-day Bion-M 1 biosatellite mission. While the training effectively mitigated aggression, significant animal loss due to a hardware malfunction and microgravity-related behaviors highlighted critical needs for future habitat design.
A study using fruit flies reveals that developing in microgravity specifically impairs the Toll immune pathway, critical for fighting fungal infections, while leaving the antibacterial Imd pathway intact. This immune dysfunction is linked to a significant stress response, providing key insights into astronaut health risks.
A study on mice found that both 13 days of spaceflight and ground-based hind limb unloading caused similar, measurable changes in the electrical properties of muscle. This suggests Electrical Impedance Myography (EIM) is a promising non-invasive technology for monitoring muscle atrophy in astronauts.
This review synthesizes research on the IRE1 protein, a critical sensor in the cell's Endoplasmic Reticulum (ER). It reveals IRE1's dual role, acting as a switch that either promotes cell survival under mild stress or actively triggers cell death when stress is severe, a finding with major implications for astronaut health in space.
A 21-day mouse study using a partial weight suspension system reveals that bone density and muscle mass loss are linearly proportional to the degree of mechanical unloading. Even a 30% reduction in weight-bearing caused significant deterioration, providing critical data for assessing astronaut health risks in partial gravity environments like Mars and highlighting the need for robust countermeasures.
A study in Drosophila reveals that the SUN protein Spag4 is critical for male fertility by anchoring the sperm tail's basal body to the nucleus. This process unexpectedly relies on the coiled-coil protein Yuri Gagarin, not a traditional KASH partner, defining a novel pathway essential for sperm development and cellular architecture.
Researchers developed a Partial Weight Suspension (PWS) system for mice to simulate reduced gravity. A 21-day study simulating Mars gravity (38% body weight) resulted in significant muscle and bone loss, including a 23% decrease in gastrocnemius mass and a 27% reduction in femoral strength, primarily due to suppressed bone formation. This model is crucial for understanding health risks on long-duration missions and for testing countermeasures.