Astronauts In Space Research Articles

A multifractal approach to understanding Forbush Decrease events: Correlations with geomagnetic storms and space weather phenomena

The Forbush decrease phenomenon has significant impacts on several environmental conditions, including interference in radio communications, satellite navigation systems, and the health of astronauts in space, among others. It is characterized by a temporary and noticeable reduction in the observed flux of galactic cosmic rays recorded at the Earth’s surface. This decrease occurs due to the modulation of cosmic rays through their interaction with shock waves generated by coronal mass ejections. As these shock waves traverse the interplanetary medium, which includes the solar wind and galactic cosmic rays, they exert compression forces on the cosmic ray flux, leading to a reduction in observed flux levels at Earth. This study investigates Forbush Decrease events across different solar cycles and explores their correlation with geomagnetic storm conditions using multifractal detrended fluctuation analysis. The findings indicate variations in the multifractal spectra for series under different geomagnetic storm conditions compared to the full Forbush decrease series. Moreover, it is observed that the amplitude of the multifractal spectrum is greater in the series that include events with a maximum Kp index exceeding 6, suggesting a significant influence of geomagnetic storm conditions on the fractality and variability of Forbush Decrease magnitudes.

A method to predict space radiation biological effectiveness for non-cancer effects following intense Solar Particle Events

In addition to the continuous exposure to cosmic rays, astronauts in space are occasionally exposed to Solar Particle Events (SPE), which involve less energetic particles but can deliver much higher doses. The latter can exceed several Gy in a few hours for the most intense SPEs, for which non-stochastic effects are thus a major concern. To identify adequate shielding conditions that would allow respecting the dose limits established by the various space agencies, the absorbed dose in the considered organ/tissue must be multiplied by the corresponding Relative Biological Effectiveness (RBE), which is a complex quantity depending on several factors including particle type and energy, considered biological effect, level of effect (and thus absorbed dose), etc.While in several studies only the particle-type dependence of RBE is taken into account, in this work we developed and applied a new approach where, thanks to an interface between the FLUKA Monte Carlo transport code and the BIANCA biophysical model, the RBE dependence on particle energy and absorbed dose was also considered. Furthermore, we included in the considered SPE spectra primary particles heavier than protons, which in many studies are neglected. This approach was then applied to the October 2003 SPE (the most intense SPE of solar cycle 23, also known as “Halloween event”) and the January 2005 event, which was characterized by a lower fluence but a harder spectrum, i.e., with higher-energy particles. The calculation outcomes were then discussed and compared with the current dose limits established for skin and blood forming organs in case of 30-days missions.This work showed that the BIANCA model, if interfaced to a radiation transport code, can be used to calculate the RBE values associated to Solar Particle Events. More generally, this work emphasizes the importance of taking into account the RBE dependence on particle energy and dose when calculating equivalent doses.

Space Ultrasound: A Proposal for Competency-based Ultrasound Training for In-flight Space Medicine.

Space travel has transformed in the past several years. Given the burgeoning market for space tourism, in-flight medical emergencies are likely to be expected. Ultrasound is one of the few diagnostic and therapeutic modalities available for astronauts in space. However, while point-of-care ultrasound (POCUS) is available, there is no current standard of training for astronaut preparation. We suggest an organized and structured methodology by which astronauts should best prepare for space with the medical equipment available on board. As technology continues to evolve, the assistance of other artificial intelligence and augmented reality systems are likely to facilitate training and dynamic real-time needs during space emergencies. Summary: As space tourism continues to evolve, an organized methodology for POCUS use is advised to best prepare astronauts for space.

A Review of Numerical Models of Radiation Injury and Repair Considering Subcellular Targets and the Extracellular Microenvironment.

Astronauts in space are subject to continuous exposure to ionizing radiation. There is concern about the acute and late-occurring adverse health effects that astronauts could incur following a protracted exposure to the space radiation environment. Therefore, it is vital to consider the current tools and models used to describe and study the organic consequences of ionizing radiation exposure. It is equally important to see where these models could be improved. Historically, radiobiological models focused on how radiation damages nuclear deoxyribonucleic acid (DNA) and the role DNA repair mechanisms play in resulting biological effects, building on the hypotheses of Crowther and Lea from the 1940s and 1960s, and they neglected other subcellular targets outside of nuclear DNA. The development of these models and the current state of knowledge about radiation effects impacting astronauts in orbit, as well as how the radiation environment and cellular microenvironment are incorporated into these radiobiological models, aid our understanding of the influence space travel may have on astronaut health. It is vital to consider the current tools and models used to describe the organic consequences of ionizing radiation exposure and identify where they can be further improved.

Health Support System for Space Astronauts

Space disease among astronauts presents a complex medical challenge with elusive origins, resisting traditional diagnostic methods. This study explores a comparative analysis between the rotational dynamics of the twelve-organ presidency and circadian rhythms, revealing a consistent stagnation in the visceral organ rhythm during the president period of Sanjiao in space astronauts. This abnormal rhythm prompts an investigation into its potential role as the fundamental cause of space disease. Experiments on Earth, employing an Organ Rhythm Conditioner and specific regulating programs, suggest a promising method to alleviate this condition. However, the validity of this approach remains pending verification. Beyond space disease, the study advocates for a comprehensive diagnostic framework, considering factors such as onset time, rotational dynamics of visceral organs, JingQi pathways, and optimal physiological function time. Treatment strategies focusing on regulating visceral organ rhythms offer a new perspective for analyzing the etiology of diverse diseases.

The Solar Particle Acceleration Radiation and Kinetics (SPARK) Mission Concept

Particle acceleration is a fundamental process arising in many astrophysical objects, including active galactic nuclei, black holes, neutron stars, gamma-ray bursts, accretion disks, solar and stellar coronae, and planetary magnetospheres. Its ubiquity means energetic particles permeate the Universe and influence the conditions for the emergence and continuation of life. In our solar system, the Sun is the most energetic particle accelerator, and its proximity makes it a unique laboratory in which to explore astrophysical particle acceleration. However, despite its importance, the physics underlying solar particle acceleration remain poorly understood. The SPARK mission will reveal new discoveries about particle acceleration through a uniquely powerful and complete combination of γ-ray, X-ray, and EUV imaging and spectroscopy at high spectral, spatial, and temporal resolutions. SPARK’s instruments will provide a step change in observational capability, enabling fundamental breakthroughs in our understanding of solar particle acceleration and the phenomena associated with it, such as the evolution of solar eruptive events. By providing essential diagnostics of the processes that drive the onset and evolution of solar flares and coronal mass ejections, SPARK will elucidate the underlying physics of space weather events that can damage satellites and power grids, disrupt telecommunications and GPS navigation, and endanger astronauts in space. The prediction of such events and the mitigation of their potential impacts are crucial in protecting our terrestrial and space-based infrastructure.

Serum multi-omics analysis in hindlimb unloading mice model: Insights into systemic molecular changes and potential diagnostic and therapeutic biomarkers

Microgravity, in space travel and prolonged bed rest conditions, induces cardiovascular deconditioning along with skeletal muscle mass loss and weakness. The findings of microgravity research may also aid in the understanding and treatment of human health conditions on Earth such as muscle atrophy, and cardiovascular diseases. Due to the paucity of biomarkers and the unknown underlying mechanisms of cardiovascular and skeletal muscle deconditioning in these environments, there are insufficient diagnostic and preventative measures. In this study, we employed hindlimb unloading (HU) mouse model, which mimics astronauts in space and bedridden patients, to first evaluate cardiovascular and skeletal muscle function, followed by proteomics and metabolomics LC-MS/MS-based analysis using serum samples. Three weeks of unloading caused changes in the function of the cardiovascular system in c57/Bl6 mice, as seen by a decrease in mean arterial pressure and heart weight. Unloading for three weeks also changed skeletal muscle function, causing a loss in grip strength in HU mice and atrophy of skeletal muscle indicated by a reduction in muscle mass. These modifications were partially reversed by a two-week recovery period of reloading condition, emphasizing the significance of the recovery process. Proteomics analysis revealed 12 dysregulated proteins among the groups, such as phospholipid transfer protein, Carbonic anhydrase 3, Parvalbumin alpha, Major urinary protein 20 (Mup20), Thrombospondin-1, and Apolipoprotein C-IV. On the other hand, metabolomics analysis showed altered metabolites among the groups such as inosine, hypoxanthine, xanthosine, sphinganine, l-valine, 3,4-Dihydroxyphenylglycol, and l-Glutamic acid. The joint data analysis revealed that HU conditions mainly impacted pathways such as ABC transporters, complement and coagulation cascades, nitrogen metabolism, and purine metabolism. Overall, our results indicate that microgravity environment induces significant alterations in the function, proteins, and metabolites of these mice. These observations suggest the potential utilization of these proteins and metabolites as novel biomarkers for assessing and mitigating cardiovascular and skeletal muscle deconditioning associated with such conditions.

Simulated microgravity attenuates skin wound healing by inhibiting dermal fibroblast migration via F-actin/YAP signaling pathway.

Skin and its cell components continuously subject to extrinsic and intrinsic mechanical forces and are mechanical sensitive. Disturbed mechanical homeostasis may lead to changes in skin functions. Gravity is the integral mechanical force on the earth, however, how gravity contributes to the maintenance of skin function and how microgravity in space affects the wound healing are poorly understood. Here, using microgravity analogs, we show that simulated microgravity (SMG) inhibits the healing of cutaneous wound and the accumulation of dermal fibroblasts in the wound bed. In vitro, SMG inhibits the migration of human foreskin fibroblast cells (HFF-1), and decreases the F-actin polymerization and YAP (yes-associated protein) activity. The SMG-inhibited migration can be recovered by activating YAP or F-actin polymerization using lysophosphatidic acid (LPA) or jasplakinolide (Jasp), suggesting the involvement of F-actin/YAP signaling pathway in this process. In SMG rats, LPA treatment improves the cutaneous healing with increased dermal fibroblasts in the wound bed. Together, our results demonstrate that SMG attenuates the cutaneous wound healing by inhibiting dermal fibroblast migration, and propose the crucial role of F-actin/YAP mechano-transduction in the maintenance of skin homeostasis under normal gravity, and YAP as a possible therapeutic target for the skin care of astronauts in space.

Impacts of radiation exposure, hindlimb unloading, and recovery on murine skeletal muscle cell telomere length

Astronauts are exposed to harsh conditions, including cosmic radiation and microgravity. Spaceflight elongates human telomeres in peripheral blood, which shorten upon return to Earth and approach baseline levels during postflight recovery. Astronauts also encounter muscle atrophy, losing up to 20% loss of muscle mass on spaceflights. Telomere length changes in muscle cells of astronauts remain unexplored. This study investigates telomere alterations in grounded mice experiencing radiation exposure and muscle atrophy, via a hindlimb unloading spaceflight mimicking model. We find telomere lengthening is present in muscle stem cells and in myofiber nuclei, but not in muscle-resident endothelial cells. We further assessed telomere length in the model following hindlimb unloading recovery. We find that telomere length failed to return to baseline values. Our results suggest a role for telomeres in muscle acclimatization, which is relevant for the well-being of astronauts in space, and upon their return to Earth.

Response of cardiac pulse parameters in humans at various inclinations via 360° rotating platform for simulated microgravity perspective

On the Earth, the human body is designed and adapted to function under uniform gravitational acceleration. However, exposure to microgravity or weightlessness as experienced by astronauts in space causes significant alterations in the functioning of the human cardiovascular system. Due to limitations in using real microgravity platforms, researchers opted for various ground-based microgravity analogs including head-down tilt (HDT) at fixed inclination. However, in the present study, an investigation of response of various cardiac parameters and their circulatory adaptation in 18 healthy male subjects was undertaken by using an indigenously developed 360° rotating platform. Cardiac pulse was recorded from 0° to 360° in steps of 30° inclination using piezoelectric pulse sensor (MLT1010) and associated cardiac parameters were analyzed. The results showed significant changes in the pulse shape while an interesting oscillating pattern was observed in associated cardiac parameters when rotated from 0° to 360°. The response of cardiac parameters became normal after returning to supine posture indicating the ability of the cardiovascular system to reversibly adapt to the postural changes. The observed changes in cardiac parameters at an inclination of 270°, in particular, were found to be comparable with spaceflight studies. Based on the obtained results and the proposed extended version of fluid redistribution mechanism, we herewith hypothesize that the rotation of a subject to head down tilt inclination (270°) along with other inclinations could represent a better microgravity analog for understanding the cumulative cardiac response of astronauts in space, particularly for short duration space missions.

Carie - The Space Pet

Robotics is the fusion of science, engineering, and technology that creates robots, or machines, that mimic or take the place of human beings in performing tasks. Multiple sorts of robotics are possible. It is also possible to use robotics for space research. Physically and mentally challenging situations might arise for humans during space travel. The use of technology can help us to some extent get past the mental challenges as the physical challenges are unavoidable. We employ robotics in order to get over mental obstacles. To reach the objective of promoting astronaut wellness in space, we combine robotics with a number of other technologies. This project is aimed at developing an autonomous robot companion for astronauts during space missions. The objective is to provide real time monitoring, forecasting capability and navigation assistance in order to ensure the safety, efficiency and well-being of astronauts. The robot companion is capable of monitoring astronaut's health conditions and detecting potential problems at an early stage by integrating high resolution sensors and sophisticated algorithms. The robot aims to improve the overall experience and performance of astronauts in space by applying predictive analytical tools and advanced navigation systems.

Time perception in astronauts on board the International Space Station

We perceive the environment through an elaborate mental representation based on a constant integration of sensory inputs, knowledge, and expectations. Previous studies of astronauts on board the International Space Station have shown that the mental representation of space, such as the perception of object size, distance, and depth, is altered in orbit. Because the mental representations of space and time have some overlap in neural networks, we hypothesized that perception of time would also be affected by spaceflight. Ten astronauts were tested before, during, and after a 6–8-month spaceflight. Temporal tasks included judging when one minute had passed and how long it had been since the start of the workday, lunch, docking of a vehicle, and a spacewalk. Compared to pre-flight estimates, there is a relative overestimation for the 1-min interval during the flight and a relative underestimation of intervals of hours in duration. However, the astronauts quite accurately estimated the number of days since vehicle dockings and spacewalks. Prolonged isolation in confined areas, stress related to workload, and high-performance expectations are potential factors contributing to altered time perception of daily events. However, reduced vestibular stimulations and slower motions in weightlessness, as well as constant references to their timeline and work schedule could also account for the change in the estimation of time by the astronauts in space.

Analysis of Milorganite’s ability to sustain growth of Ocimum basilicum in simulated Martian soil

In years to come, it will be important to discover if life on Mars is a realistic option. As the population continues to grow and resources begin to dwindle, the possibility of colonizing other planets gives hope to humankind that extinction may be avoidable. Previous research suggests that some types of plants are able to survive the harsh conditions on Mars. This research aimed to discover if Milorganite could improve the growth of Ocimum basilicum (basil) in simulated Martian soil. Milorganite is a waste product-based fertilizer that was chosen to simulate the fecal matter of astronauts in space. We observed that basil could not grow in the simulated soil across all concentrations of Milorganite. We then shifted the study toward transplanting mature basil plants into the same soil with differing amounts of Milorganite. During the experiment, we observed that higher concentrations of Milorganite killed the basil plants. However, results were insignificant, suggesting that Milorganite has no effect on the growth of basil in simulated Martian soil. We watered some plants with a Miracle-Gro mixture water and some with tap water to ensure the type of water wasn’t interfering with the results of the Milorganite. The Miracle-Gro did not significantly improve the conditions of the soil across all levels of Milorganite.

Any Island by Ilka Scobie

Reviewed by: Any Island by Ilka Scobie Lynn McGee (bio) any island Ilka Scobie Spuyten Duyvil http://www.spuytenduyvil.net/any-island.html 56 pages; Print, $16.00 Native New Yorker Ilka Scobie is not infatuated with the city of her birth. Her regard for the urban puzzle known as New York City is a mature love recognizing its flaws with unapologetic nostalgia. She pulls this off with aplomb, as in "2B": "Brooklyn, where I'm from, boasts mad Bs / Bedford Stuyvesant, Bed-Stuy, do or die / Brownsville, or the Ville / Bay Ridge of sweeping bridge." In "Taxi" she mourns the direction the economy of New York City has taken, as evidenced by the extinction of the iconic Checker cab: "Soon you will be a nostalgic footnote, like Gem Spa, egg creams, / The Village Voice, and subway tokens. / We are left with Uber, Via, Lyft; acronyms for anonymity." In "What to Wear to the Demonstration," a tone-setting poem that anchors the collection's voice, the first line is "Black, of course," and in the lines that follow the speaker fuses style with necessity, including the necessity [End Page 133] of pushing back: "Black, sophisticated, stylish, sensual / hides the grim of urban life. / Garbed in black, we are an army." As for what to push back against, Scobie moves her scope from local to national in "Dark Daze" and gives a nod to inclusion: "If you are a woman, be very afraid … And if you are gay, do not believe his [a reference to a "commander in chief" who is "a chauvinist"] lying lips / There will be no support for an Equality Act." That spirit of inclusiveness might seem to wane in "To the Boy Who Wants to be a Girl," as the speaker looks "straight into" the "innocent eyes" of an individual who is transitioning from male and female, and admits, "it's beyond my middle-aged, middle-class, / hetero comprehension, why, lovely child / that you are, / there is an urgency to deny the dick between your legs." Some will lose connection with the speaker in that moment, but overall the tone of moral authority in Any Island resonates convincingly, at least for this reader. "On the Destruction of the Seventh-Century Assyrian Winged Bull in Mosul, Iraq" appears to reference the invasion of Iraq after 9/11 and observes that "No sapient shards penetrate the hatred / That shatters ancient artifacts … Whoever would destroy the creation of my hands, / Let the great lord destroy his name and posterity on earth." Spinning off from other cultural events that have political overtones, "Space Pioneers" provides an epigraph: "On Nov. 17, 2011, the Congress awarded gold medals to the original astronauts," and while John Glenn, Neil Armstrong, Buzz Aldrin, and Michael Collins are not named in the poem, the speaker compares these "space pioneers" with women emerging in the same era as social pioneers. If the reader brings to the poem the knowledge that John Glenn flew into space in 1962 and it wasn't until 1974 that women could open credit in their own name, it can be satisfying to read, "Where is our well-deserved recognition / For venturing where no (wo)man has tread before / Inner space astronauts." A spiky flowerlike image in a drawing by Elisabeth Kley, Untitled Drawing, complements this poem. Other visuals throughout the collection include the ink drawing Ugo Rondinno, by einunddreissigsteroktoberzweitausendundsieben; and a moody, massive drawing of a tree that echoes the poem "Millennium": "How naïve our ancestors, who believed / in limitless forest and eternal fauna. / Worshipping consumerism, we squandered nature / for the fantasy of virgin birth." [End Page 134] Recognized as a political poet—alongside New York City writers of similar generation including Sparrow, Jeffrey Cyphers Wright, Lewis Warsh, Bernadette Mayer, and others—in person, Scobie reads her work aloud with a certainty that is consistent with her critical reviews appearing in Brooklyn Rail and other venues. The insight of a lifelong resident who has seen her city evolve over decades dovetails with the perspective of a traveler in "Sakura," where Scobie reveres the ginkgo trees of the Brooklyn she grew up in and bemoans "Trees cut to make room for architectural / grandiosity...

Variation in Cosmic-Ray Intensity Lags Sunspot Number: Implications of Late Opening of Solar Magnetic Field

Abstract Galactic cosmic rays (GCRs), the highly energetic particles that may raise critical health issues for astronauts in space, are modulated by solar activity, with their intensity lagging behind the variation in sunspot number (SSN) by about one year. Previously, this lag has been attributed to the combined effect of outward convecting solar wind and inward propagating GCRs. However, the lag’s amplitude and its solar-cycle dependence are still not fully understood. By investigating the solar surface magnetic field, we find that the source of heliospheric magnetic field—the open magnetic flux on the Sun—already lags behind SSN before it convects into the heliosphere along with the solar wind. The delay during odd cycles is longer than that during sequential even cycles. Thus, we propose that the GCR lag is primarily due to the very late opening of the solar magnetic field with respect to SSN, though solar wind convection and particle transport in the heliosphere also matter. We further investigate the origin of the open flux from different latitudes of the Sun and find that the total open flux is significantly contributed by that from low latitudes, where coronal mass ejections frequently occur and also show an odd–even cyclic pattern. Our findings challenge existing theories, and may serve as the physical basis of long-term forecasts of radiation dose estimates for manned deep-space exploration missions.

Editorial: Are Big Data, Artificial Intelligence, Augmented Reality, Robotics, Teledentistry, and Metaverse Just Buzz Terms, or Do They Indicate a Paradigm Shift in Prosthodontics?

Editorial: Are Big Data, Artificial Intelligence, Augmented Reality, Robotics, Teledentistry, and Metaverse Just Buzz Terms, or Do They Indicate a Paradigm Shift in Prosthodontics?

Stem Cell and Regenerative Methods for Space Personnel

Significant deterioration of organs and tissues occurs in astronauts as a result of cosmic radiation exposure. This is a major obstacle to the developing space industry involving extended space exploration, commercial asteroid mining and the colonization of Earth’s moon and Mars. Cosmic radiation includes galactic cosmic rays, and solar particle events of x-rays and gamma rays that penetrate deeply inducing DNA damage. Potential medical issues for astronauts arising from radiation include cancer, rapid aging, sterility, impaired immune system, re-emergence of pathogenic viruses, neurodegeneration and memory impairment. In summary, there are potentially catastrophic consequences for space personnel from prolonged exposure to radiation. Upregulating the regeneration of tissue using advances in stem cell technology would be a plausible method to counteract radiation damage triggering cellular degeneration. Stem cells are ‘survival’ cells and are responsible for the ongoing repair and regeneration of the human body. Increasing the number of available stem cells improves the regenerative capacity of the body. Current stem cell technology is not possible in space, as it requires multiple medical specialists using major hospital surgical and laboratory equipment. The authors have developed a portable stem cell biotechnology kit that is compact, lightweight, and simple to operate and could be performed by astronauts in space on a frequent basis to potentially regenerate affected tissue and reverse the effects of cosmic radiation. The technology uses laboratory validated peptide hydrogels for stem cell migration and expansion. The astronaut only requires donating a small amount of blood or adipose tissue. Preliminary analysis showed stem cells have high yield, excellent cell viability, and demonstrate normal stem cell health parameters of autophagy and annexin V. This approach may help to balance the degeneration / regeneration cycle of the body subject to radiation. Space personnel can be trained in a short period of time to perform the technology with safety and efficacy.

Al-Ḥīlah al-Shar'iyyah as a Method in Responding to Prayer Problems in Space

This paper describes the prayer problem for Muslim astronauts in space and provides solutions using the al-ḥīlah al-shar'iyyah method. This paper is qualitative with descriptive-analytic research methods with data sourced from the literature. This paper finds that with the al-ḥīlah al-shar'iyyah method, Muslim astronauts can still carry out their obligations as a mukallaf. They get rukhṣah (dispensation), both related to the direction of the qibla and the determination of prayer times. Rukhṣah, as a result of the al-ḥīlah al-shar'iyyah method, helps Muslim astronauts in two conditions at once, first, in their position as scientists who carry out scientific missions. Second, in his position as a Muslim with his obligations to carry out the sharī'ah.

Anti-RANKL monoclonal antibody and bortezomib prevent mechanical unloading-induced bone loss.

Bone loss is a major health concern for astronauts during long-term spaceflight and for patients during prolonged bed rest or paralysis. It is essential to develop therapeutic strategies to combat the bone loss occurring in people afflicted with disuse atrophy on earth as well as in astronauts in space, especially during prolonged missions. Although several drugs have been demonstrated for treating postmenopausal osteoporosis or bone-related diseases, their effects on microgravity-induced bone loss are still unclear. Here, we employed the hindlimb-unloading (HLU) tail suspension model and compared the preventive efficiencies of five agents including alendronate (ALN), raloxifene (Rox), teriparatide (TPTD), anti-murine RANKL monoclonal antibody (anti-RANKL) and proteasome inhibitor bortezomib (Bzb) on mechanical unloading-induced bone loss. Bone mineral density (BMD) was measured by quantitative computed tomography. The osteoblastic and osteoclastic activity were measured by serum ELISA, histology analysis, and histomorphometric analysis. Compared to the control, ALN and anti-RANKL antibody could restore bone mass close to sham levels by inhibiting bone resorption. Bzb could increase the whole bone mass and strength by inhibiting bone resorption and promoting bone formation simultaneously. Meanwhile, Rox did not affect bone loss caused by HLU. TPTD stimulated cortical bone formation but the total bone mass was not increased significantly. We demonstrated for the first time that anti-RANKL antibody and Bzb had a positive effect on preventing mechanical unloading-induced bone loss. This finding puts forward the potential use of anti-RANKL and Bzb on bone loss therapies or prophylaxis of astronauts in spaceflight.

Role of Apoptosis in Wound Healing and Apoptosis Alterations in Microgravity.

Functioning as the outermost self-renewing protective layer of the human organism, skin protects against a multitude of harmful biological and physical stimuli. Consisting of ectodermal, mesenchymal, and neural crest-derived cell lineages, tissue homeostasis, and signal transduction are finely tuned through the interplay of various pathways. A health problem of astronauts in space is skin deterioration. Until today, wound healing has not been considered as a severe health concern for crew members. This can change with deep space exploration missions and commercial spaceflights together with space tourism. Albeit the molecular process of wound healing is not fully elucidated yet, there have been established significant conceptual gains and new scientific methods. Apoptosis, e.g., programmed cell death, enables orchestrated development and cell removal in wounded or infected tissue. Experimental designs utilizing microgravity allow new insights into the role of apoptosis in wound healing. Furthermore, impaired wound healing in unloading conditions would depict a significant challenge in human-crewed exploration space missions. In this review, we provide an overview of alterations in the behavior of cutaneous cell lineages under microgravity in regard to the impact of apoptosis in wound healing. We discuss the current knowledge about wound healing in space and simulated microgravity with respect to apoptosis and available therapeutic strategies.