Potential Liver Risks in those Exposed to Zero Gravity Environments

 Although alcohol is not allowed on the international space station, astronauts still have reason to watch their livers. A recent study published in Nature shows potential risks associated with microgravity.The study, led by the University of Tsubuka, Japan, found that mice sent to the International Space Station had their livers stressed out by the time they returned to Earth. If this same factor is also causing risk to astronauts, then it provides a potentially serious problem to fix. But to understand it in humans, it is often easier to assess it first in mice. 

Animal studies are often used to identify potential risks to humans, and find ways to address them. Different model species (E.g. rats, mice,fruit flies, yeast) are used for different research goals. Mice and humans are both mammals so their liver structures are largely similar, and experience stress in many of the same ways. This study found that the oxidative stress of a zero gravity wore down the liver’s antioxidant reserves. By the time they returned to Earth the mice had high levels of gene expression for those related to fighting oxidative stress, and had depleted their antioxidant capacity. The stress was less bad in those mice exposed to artificial gravity, which is a positive sign at least. 

The practical application of this research is very hopeful. The stress caused by microgravity could be mitigated by the use of artificial gravity. Any long term space living would require some form of artificial gravity to combat much of the liver damage, and, according to professor Iwao Ohtsu of the University of Tsubuka, “whereas those caused by other environmental effects could be treated with alternative solutions, such as the addition of dietary supplements to astronauts' diets". With those two factors in mind, hopefully those living in low gravity environments will have one less health worry to deal with.

William Sobchuk (9)
https://www.sciencedaily.com/releases/2021/12/211206113023.htm
https://www.tsukuba.ac.jp/en/research-news/20211129140000.html
https://www.nature.com/articles/s41598-021-01129-1