Research Containing: Space Flight

Simulated microgravity alters multipotential differentiation of rat mesenchymal stem cells in association with reduced telomerase activity

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Microgravity is one of the most important characteristics in space flight. Exposure to microgravity results in extensive physiological changes in humans. Bone loss is one of the changes with serious consequences: however. the mechanism retains unclear. As the origin of osteoprogenitors, mesenchymal stein cells (MSCs) may play an important role in it. After cultured under simulated microgravity (in a rotary cell culture system, RCCS), MSCs were stained using oil red O to identify adipocytes. The mRNA level of bone morphogenetic protein (BMP)-2 and peroxisome proliferators-activated receptor (PPAR) gamma 2 was determined by RT-PCR. Otherwise, MSCs were induced to osteogenic differentiation after microgravity culture, and then the activity of alkaline phosphatase (ALP) was determined by PNPP and the content of osteocalcin (OC) by ELISA. Furthermore, the telomerase activity in MSCs was measured by TRAP. The results showed that simulated microgravity inhibited osteoblastic differentiation and induced adipogenic differentiation accompanied by the change of gene expression of BMP-2 and PPAR gamma 2 in MSCs. Meanwhile, the telomerase activity decreased significantly in MSCs under simulated microgravity. The reduced bone formation in space flight may partly be due to the altered potential differentiation of MSCs associated with telomerase activity which plays a key role in regulating the lifespan of cell proliferation and differentiation. Therefore. telomerase activation/replacement may act as a potential countermeasure for microgravity-induced bone loss. (C) 2008 Elsevier Ltd. All rights reserved.

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Spaceflight and hind limb unloading induce similar changes in electrical impedance characteristics of mouse gastrocnemius muscle

by cfynanon 9 June 2015in Biology & Biotechnology No comment

OBJECTIVE: To assess the potential of electrical impedance myography (EIM) to serve as a marker of muscle fiber atrophy and secondarily as an indicator of bone deterioration by assessing the effects of spaceflight or hind limb unloading. METHODS: In the first experiment, 6 mice were flown aboard the space shuttle (STS-135) for 13 days and 8 earthbound mice served as controls. In the second experiment, 14 mice underwent hind limb unloading (HLU) for 13 days; 13 additional mice served as controls. EIM measurements were made on ex vivo gastrocnemius muscle. Quantitative microscopy and areal bone mineral density (aBMD) measurements of the hindlimb were also performed. RESULTS: Reductions in the multifrequency phase-slope parameter were observed for both the space flight and HLU cohorts compared to their respective controls. For ground control and spaceflight groups, the values were 24.7+/-1.3 degrees /MHz and 14.1+/-1.6 degrees /MHz, respectively (p=0.0013); for control and HLU groups, the values were 23.9+/-1.6 degrees /MHz and 19.0+/-1.0 degrees /MHz, respectively (p=0.014). This parameter also correlated with muscle fiber size (rho=0.65, p=0.011) for spaceflight and hind limb aBMD (rho=0.65, p=0.0063) for both groups. CONCLUSIONS: These data support the concept that EIM may serve as a useful tool for assessment of muscle disuse secondary to immobilization or microgravity.

Amphibian development in the virtual absence of gravity

by cfynanon 9 June 2015in Biology & Biotechnology No comment

To test whether gravity is required for normal amphibian development, Xenopus laevis females were induced to ovulate aboard the orbiting Space Shuttle. Eggs were fertilized in vitro, and although early embryonic stages showed some abnormalities, the embryos were able to regulate and produce nearly normal larvae. These results demonstrate that a vertebrate can ovulate in the virtual absence of gravity and that the eggs can develop to a free-living stage.

Spaceflight reduces vasoconstrictor responsiveness of skeletal muscle resistance arteries in mice

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Cardiovascular adaptations to microgravity undermine the physiological capacity to respond to orthostatic challenges upon return to terrestrial gravity. The purpose of the present study was to investigate the influence of spaceflight on vasoconstrictor and myogenic contractile properties of mouse gastrocnemius muscle resistance arteries. We hypothesized that vasoconstrictor responses acting through adrenergic receptors [norepinephrine (NE)], voltage-gated Ca2+ channels (KCl), and stretch-activated (myogenic) mechanisms would be diminished following spaceflight. Feed arteries were isolated from gastrocnemius muscles, cannulated on glass micropipettes, and physiologically pressurized for in vitro experimentation. Vasoconstrictor responses to intraluminal pressure changes (0–140 cmH2O), KCl (10–100 mM), and NE (10−9-10−4 M) were measured in spaceflown (SF; n = 11) and ground control (GC; n = 11) female C57BL/6 mice. Spaceflight reduced vasoconstrictor responses to KCl and NE; myogenic vasoconstriction was unaffected. The diminished vasoconstrictor responses were associated with lower ryanodine receptor-2 (RyR-2) and ryanodine receptor-3 (RyR-3) mRNA expression, with no difference in sarcoplasmic/endoplasmic Ca2+ ATPase 2 mRNA expression. Vessel wall thickness and maximal intraluminal diameter were unaffected by spaceflight. The data indicate a deficit in intracellular calcium release via RyR-2 and RyR-3 in smooth muscle cells as the mechanism of reduced contractile activity in skeletal muscle after spaceflight. Furthermore, the results suggest that impaired end-organ vasoconstrictor responsiveness of skeletal muscle resistance arteries contributes to lower peripheral vascular resistance and less tolerance of orthostatic stress in humans after spaceflight.

Adrenocortical and immune responses following short- and long-duration spaceflight

by cfynanon 9 June 2015in Biology & Biotechnology No comment

INTRODUCTION: Short-term spaceflight is associated with significant but reversible immunological alterations. However, little information exists on the effects of long-duration spaceflight on neuroimmune responses. METHODS: We collected multiple pre- and postflight samples from Shuttle and International Space Station (ISS) crewmembers in order to compare adrenocortical and immune responses between short- (approximately 11 d) and long-duration (approximately 180 d) spaceflight. RESULTS: In Shuttle crewmembers, increased stress hormone levels and altered leukocyte subsets were observed prior to launch and at landing. Additionally, typical stress-induced shifts in leukocyte and lymphocyte subsets, as well as the percentage of T-cells capable of producing intracellular IFN-gamma were also decreased just before launch and immediately after landing. Plasma IL-10 levels were increased before launch but not postflight. No preflight changes occurred in ISS crewmembers, but long-duration crewmembers exhibited significantly greater spikes in both plasma and urinary cortisol at landing as compared to Shuttle crewmembers. The percentage of T-cells capable of producing intracellular IFN-gamma was decreased in ISS crewmembers. Plasma IL-10 was increased postflight. Unexpectedly, stress-induced shifts in lymphocyte subpopulations were absent after long-duration flights despite significantly increased stress hormones at landing. CONCLUSION: Our results demonstrate significant differences in neuroimmune responses between astronauts flying on short-duration Shuttle missions versus long-duration ISS missions, and they agree with prior studies demonstrating the importance of mission duration in the magnitude of these changes.

Microgravity effects on thylakoid, single leaf, and whole canopy photosynthesis of dwarf wheat

by cfynanon 9 June 2015in Biology & Biotechnology No comment

The concept of using higher plants to maintain a sustainable life support system for humans during long-duration space missions is dependent upon photosynthesis. The effects of extended exposure to microgravity on the development and functioning of photosynthesis at the leaf and stand levels were examined onboard the International Space Station (ISS). The PESTO (Photosynthesis Experiment Systems Testing and Operations) experiment was the first long-term replicated test to obtain direct measurements of canopy photosynthesis from space under well-controlled conditions. The PESTO experiment consisted of a series of 21-24 day growth cycles of Triticum aestivum L. cv. USU Apogee onboard ISS. Single leaf measurements showed no differences in photosynthetic activity at the moderate (up to 600 micromol m(-2) s(-1)) light levels, but reductions in whole chain electron transport, PSII, and PSI activities were measured under saturating light (>2,000 micromol m(-2) s(-1)) and CO(2) (4000 micromol mol(-1)) conditions in the microgravity-grown plants. Canopy level photosynthetic rates of plants developing in microgravity at approximately 280 micromol m(-2) s(-1) were not different from ground controls. The wheat canopy had apparently adapted to the microgravity environment since the CO(2) compensation (121 vs. 118 micromol mol(-1)) and PPF compensation (85 vs. 81 micromol m(-2) s(-1)) of the flight and ground treatments were similar. The reduction in whole chain electron transport (13%), PSII (13%), and PSI (16%) activities observed under saturating light conditions suggests that microgravity-induced responses at the canopy level may occur at higher PPF intensity.

Microgravity effects on leaf morphology, cell structure, carbon metabolism and mRNA expression of dwarf wheat

by cfynanon 9 June 2015in Biology & Biotechnology No comment

The use of higher plants as the basis for a biological life support system that regenerates the atmosphere, purifies water, and produces food has been proposed for long duration space missions. The objective of these experiments was to determine what effects microgravity (microg) had on chloroplast development, carbohydrate metabolism and gene expression in developing leaves of Triticum aestivum L. cv. USU Apogee. Gravity naive wheat plants were sampled from a series of seven 21-day experiments conducted during Increment IV of the International Space Station. These samples were fixed in either 3% glutaraldehyde or RNAlater or frozen at -25 degrees C for subsequent analysis. In addition, leaf samples were collected from 24- and 14-day-old plants during the mission that were returned to Earth for analysis. Plants grown under identical light, temperature, relative humidity, photoperiod, CO(2), and planting density were used as ground controls. At the morphological level, there was little difference in the development of cells of wheat under microg conditions. Leaves developed in mug have thinner cross-sectional area than the 1g grown plants. Ultrastructurally, the chloroplasts of microg grown plants were more ovoid than those developed at 1g, and the thylakoid membranes had a trend to greater packing density. No differences were observed in the starch, soluble sugar, or lignin content of the leaves grown in microg or 1g conditions. Furthermore, no differences in gene expression were detected leaf samples collected at microg from 24-day-old leaves, suggesting that the spaceflight environment had minimal impact on wheat metabolism.

Personal growth following long-duration spaceflight

by cfynanon 9 June 2015in Biology & Biotechnology No comment

Introduction Salutogenesis and posttraumatic growth represent personal growth and improved functioning as a result of experiencing major challenging events. These developments are not simply resilience (a return to a baseline level of well-being), but positive change in such characteristics as self-understanding, relations with others, personal values, and life goals. Space agencies and space psychologists, primarily concerned with deleterious effects and their countermeasures, have not paid much attention to such beneficial long-term aftereffects of spaceflight. Purpose To document what changes veterans of the Soviet/Russian space program report as a consequence of their experiences. Method Twenty retired male cosmonauts Mir and/or ISS cosmonauts filled out relevant self-report questionnaires. Results: Although there was little change in the relative rankings of a list of values, the scale showed an overall increase in the rated importance of all personal values, although only the increase in Self-Direction reached statistical significance. Responses to one of two post-space growth questionnaires based on the Post-Traumatic Growth Inventory (PTGI) were compared to the means of two comparison groups: 152 first-time mothers, and 926 respondents who had experienced various forms of trauma. The cosmonauts reported higher scores on the dimension of New Possibilities when compared to the new mothers and the traumatized group, and higher scores on Personal Strength and Overall PTG compared to the latter. Respondents who had spent more than a year in space, and those who flew on both Mir and ISS, were the most likely to report positive change in the domain Appreciation of Life. The other post-space career questionnaire reflected major changes in Perceptions of the Earth and of Space, and increases on a number of other dimensions, including New Possibilities and Changes in Daily Life, with positive scores that significantly exceeded the original report. Discussion It appears that cosmonauts do experience various aspects of positive personal growth following their space flights. As long-duration missions are (and will remain) the norm, it is important for the space agencies and the voyagers themselves to develop a better understanding and possible enhancement of this phenomenon.

Space shuttle flight crew spatial orientation survey results

by cfynanon 9 June 2015in Biology & Biotechnology No comment

BACKGROUND & METHOD: A survey was distributed to 77 Space Shuttle flight crew members; 40 responded covering 71 missions. The goal was to capture historical information before Shuttle retirement and to better understand subjective experiences of illusory sensations due to the transition from 1-G to microgravity and back. RESULTS: We analyzed the response data to answer four questions: 1) Do older astronauts suffer more from illusory sensations than younger astronauts? We conclude that they do not because younger flight crew had about twice the rate of illusory sensations as older flight crew. 2) Do trial head motions during re-entry in an effort to hasten readaptation to 1-G really help? Apparently not because those who made trial head motions had a 38% rate of illusory sensations whereas those who did not make trial head motions had a 15% rate of illusory sensations. 3) Do symptoms decrease as flight experience increases? Yes, as reported in other publications, although there are individual exceptions. 4) Do longer duration missions lead to more illusory sensations and readaptation difficulties than shorter duration missions? Yes, the rate of illusory sensations for longer missions was 38%, whereas it was 24% for shorter missions. DISCUSSION: Based upon our results, long-duration missions may induce orientation problems that could have significant mission impacts.

Ovarian Follicular and Luteal Development in the Spaceflight Mouse

by cfynanon 9 June 2015in Biology & Biotechnology No comment

The effects of space travel are relatively unexplored in regard to the female reproductive system. An important step in determining possible adverse effects on the human female reproductive system is the analysis of test animal data. This study analyzed the ovarian tissue of mice flown aboard space shuttle Endeavour on NASA mission STS-118. The experiment consisted of three groups of animals: two sets of control animals and a single set of flight animals. Each set consisted of twelve individual mice. The flight animals were housed in the Animal Enclosure Module (AEM) of the Commercial Biomedical Testing Module-2 (CBTM-2) over the 13 day flight. One set of control animals (baseline) were housed in standard cages at room temperature. The other set of control animals (ground control) were housed in ground based AEMs which were environmentally controlled to match the conditions aboard the shuttle Endeavour with a delay of 48 hours and subject to normal gravity. The ovarian tissue samples were fixed in 4% paraformaldehyde, paraffin embedded, sectioned, mounted, and stained using standard Hematoxylin and Eosin staining procedures, and cover-slipped. The gross morphology of the tissue was then qualitatively analyzed. The flight animals were compared to the baseline and ground control sets. The presence of developing follicles of all stages as well as the presence of corpora lutea in all three treatment groups indicates no significant gross morphological changes occur within ovarian tissue when exposed to spaceflight for 13 days or less.

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Research Containing: Space Flight

Simulated microgravity alters multipotential differentiation of rat mesenchymal stem cells in association with reduced telomerase activity

Spaceflight and hind limb unloading induce similar changes in electrical impedance characteristics of mouse gastrocnemius muscle

Amphibian development in the virtual absence of gravity

Spaceflight reduces vasoconstrictor responsiveness of skeletal muscle resistance arteries in mice

Adrenocortical and immune responses following short- and long-duration spaceflight

Microgravity effects on thylakoid, single leaf, and whole canopy photosynthesis of dwarf wheat

Microgravity effects on leaf morphology, cell structure, carbon metabolism and mRNA expression of dwarf wheat

Personal growth following long-duration spaceflight

Space shuttle flight crew spatial orientation survey results

Ovarian Follicular and Luteal Development in the Spaceflight Mouse