Page 59 - International Space Station Benefits for Humanity, 3rd edition.

astronauts exhibited decreases in visual dependence in healthy astronauts, animals and cellular cultures
that was maintained throughout 6 months on the space all provide new insights into how various critical
station and persisted for several months after returning physiological systems respond to microgravity.
to Earth. Such a persistence has implications for crew Results such as these have applications not only to
sensorimotor function (i.e., balance/locomotion) in understanding astronaut health as we explore beyond
other gravity environments beyond LEO. Investigators LEO, but also contribute to understanding the health
suggest using countermeasures of “visual gravity” of certain populations on Earth.
(up/down scenes) during long-duration travel to help
mitigate these changes in visual dependency (Harris
et al., 2017). Biology and Biomedicine
After decades of studying bone health in space, Results from space station biological research have
investigators found that resistance exercise, coupled provided insight into complex microgravity responses
with adequate energy intake and vitamin D, can in experiments ranging from single microorganisms
maintain bone in most regions for astronauts on to complex cell cultures, as well as guided successful
the space station during 4- to 6-month missions in methods to grow protein crystals in space. The addition
microgravity, providing the first evidence ever that of several recent new capabilities have also facilitated
improving nutrition and resistive exercise during an onboard analysis of microbiological and genetic
spaceflight can mitigate the expected bone mineral samples for the first time in spaceflight history.
density deficits historically seen after long-duration The unique opportunity of long-duration external
microgravity missions (Smith, Scott M. et al., 2012). exposure onboard the space station with the return
Data collected from saliva samples in astronaut immune of samples to Earth has permitted a large range of
studies on the space station indicate that latent Epstein- astrobiology experiments to be performed under actual
Barr (infectious mononucleosis) and Varicella zoster space conditions (Bryce et al., 2015; Mancinelli et al.,
(chickenpox/shingles) viruses can become infections 2015; Neuberger et al., 2015; Panitz et al., 2015).
under stressful conditions such as spaceflight (Crucian Studies such as these have shown that dormant
et al., 2008; Mehta et al., 2013; Stowe et al., 2011a; organisms from the three different domains of life—
Stowe et al., 2011b). Human T-Lymphocyte cultures Archea, Bacteria and Eukaryote—are capable of
flown to the space station showed altered genetic withstanding up to 18 months of exposure to the
expression of Interleukin-2 and/or its receptor, and, direct space environment, including solar ultraviolet
combined with ground studies, suggest a role in the light, vacuum and radiation. Notably, bacterial spores
suppressed immunity seen in astronauts (Hughes- collected from spacecraft clean rooms were capable
Fulford et al., 2015; Chang et al., 2012). Analyses of of surviving the exposure period, although solar
spleens from mice flown on the space station showed ultraviolet (UV) significantly reduced viability, which
that critical genes involved in T-cell activation of the has implications on planetary protection and
immune system were suppressed (Martinez et al., spacecraft sterilization.
2015). Another study showed that during the transition New techniques have been successful in the area
from a 1-g centrifuge to microgravity on the space of protein crystal growth in microgravity. In particular,
station, mammalian macrophage cells immediately growing protein crystals in microgravity has led to
decreased their ability to conduct oxidative burst improved methods to estimate driving force ratios
reactions critical in maintaining immune function, of crystals grown both on the ground and in space,
but the cells subsequently recovered to their normal
capabilities in less than a minute. These results
suggest that key cellular functions of multicellular
life could successfully adapt to enable long-duration
space exploration beyond LEO (Thiel et al., 2017). New capabilities in biological analyses
Researchers at the Veterans Affairs Medical Center in that have been developed and tested
San Francisco discovered a new mechanism of immune
regulation by microRNAs in immune cells based on their on the space station will enable future
spaceflight cell culture results (Hughes-Fulford et al., breakthroughs in molecular and
2015). The previously unknown mechanism is termed
“self-limiting induction” and is expected to play a role genetics research in space.
in global cellular processes including immune response
to infection, wound healing and cancer.These studies

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