Spaceflight wreaks havoc on liver metabolism

Date:
December 6, 2021
Source:
University of Tsukuba
Summary:
Researchers have demonstrated that microgravity and other
environmental factors in space play different roles in inducing
oxidative stress, which, in turn, alters the metabolism of
sulfur-containing compounds in the liver of mice. The study
highlighted steps that can be taken, such as boosting antioxidant
capacity with dietary supplements, to safeguard astronaut health.



FULL STORY ==========================================================================
The latest findings of a series of studies on mice that examined harmful effects caused by spending time in space show that gene expression related
to liver metabolism is altered in response to the space environment. The benefit of these findings is that it may be possible to offset these
changes with dietary supplementation during spaceflight.


==========================================================================
Like other inhabitants of this planet, humans have evolved for life on
Earth, not life in space or elsewhere. During spaceflight, the human body
is exposed to a harmful environment, characterized by null or microgravity
and high radiation levels. The liver is affected by spaceflight more than
any other organ -- its crucial role in neutralizing harmful substances
in the body means that spaceflight places incredible demands on the organ.

"Environmental stressors, such as high radiation and microgravity, induce
a state of oxidative stress," explains Professor Iwao Ohtsu. "To deal
with reactive oxygen and nitrogen compounds, the liver uses its limited resources, that is, antioxidant sulfur-containing compounds." The research
team conducted novel experiments to compare liver gene expression levels between mice exposed to microgravity, mice exposed to simulated gravity
on the International Space Station, and mice at ground level on Earth.

Mice that traveled to space and back had a lower antioxidant capacity
because they had lower levels of the sulfur-containing compounds (e.g., ergothioneine, cysteine, and glutathione) that play a role in protecting
cells by reducing reactive oxygen compounds, which limits free-radical
damage. Overall, many indicators of oxidative stress were evident in
the livers of these mice. In addition, there was greater expression of
genes related to oxidative stress and sulfur metabolism pathways (which
deplete levels of sulfur-containing antioxidant compounds) in mice that
had been exposed to space.

Some effects, however, only occurred in mice exposed to microgravity.

"Consequently, we were able to identify that some aspects of altered
liver metabolism are counteracted by exposure to artificial gravity,
whereas those caused by other environmental effects could be treated
with alternative solutions, such as the addition of dietary supplements
to astronauts' diets," says Professor Ohtsu.

This research not only identifies factors that could exacerbate the
likelihood of liver damage but, by clarifying the role of specific
metabolic pathways, also demonstrates the potential for existing drugs
or dietary supplements to be used to treat or prevent such damage as
humans embark on a new era of space exploration.

========================================================================== Story Source: Materials provided by University_of_Tsukuba. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Ryo Kurosawa, Ryota Sugimoto, Hiroe Imai, Kohei Atsuji, Koji Yamada,
Yusuke Kawano, Iwao Ohtsu, Kengo Suzuki. Impact of spaceflight
and artificial gravity on sulfur metabolism in mouse liver: sulfur
metabolomic and transcriptomic analysis. Scientific Reports, 2021;
11 (1) DOI: 10.1038/s41598-021-01129-1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211206113023.htm

--- up 2 days, 7 hours, 13 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)