Human beings have evolved to live with feet firmly planted on earth. There is no wonder, therefore, if our body is exposed to several dangers when it spends long periods in the microgravity environment of the International Space Station (ISS). Loss of bone density and muscle atrophy are among the most common. But not the only ones: many astronauts in fact suffer from immune dysfunctions, skin rush and inflammatory disorders while staying in space. And a new study published in Cell magazine could explain why: the fault could be of the excess hygiene, or rather, of an environment inhabited by a fraction of the thousands of microbial species with which we come into contact daily on earth.
The research was conducted by a team led by Bioingegnagner Rodolfo Salid and environmental chemistry Haoqi Nina Zhao, of the University of California of San Diego. And it is the result of a census of the microbial population that lives aboard the ISS, created thanks to the work of the astronauts, who collected 803 samples (100 times more than what was done in similar workers carried previously made), on as many surfaces of the station.
By analyzing the samples, the researchers then identified the bacteria and chemicals present inside them, thus creating a three -dimensional map of the microbial populations who live in the station, and their interactions. The results show that on the ISS there is a biodiversity of microorganisms much lower than that which is normally found in a structure built on the surface of our planet, and that the use of disinfectants in the station is so frequent and ubiquitous that it has created an environment that on earth would find comparisons solely in deliberately aseptic structures, such as hospitals.
Bacteria coexisting with astronauts
In the study, researchers cite several scientific works that in recent years have connected the reduced exposure to microorganisms to the onset of chronic inflammatory disorders and immunological problems similar to those observed in the astronauts who stay on the ISS. For this reason, they believe that in the future the theme of microbial biodiversity should be kept in mind in the design of spatial missions and habitats, to improve their habitability in view of very long -term missions, as could be for example the human exploration of Mars.
“The environments that we will build in the future, including spatial stations, could benefit from the artificial introduction of microbial communities with greater biodiversity, so that they better imitate the natural exposure to the microorganisms that we experience on earth, compared to what the highly sterile environments do to which we rely today”, comments Salid. “If we really want life to prosper even outside the earth, we cannot take only a small branch of the tree of life and launch it into space hoping that everything goes for the best. We have to start thinking about which beneficial companions we should send in the company of our astronauts, to help them develop an ecosystem that is sustainable and beneficial for everyone “.