Traveling to space changes the structure of the kidneys, with galactic radiation causing damage that could potentially jeopardize human missions to Mars, new research suggests.
Spaceflight is known to cause a number of changes in astronauts’ bodies, and as more people go into space, understanding the health risks associated with space exploration is critical to preparing for long-term, lunar and possibly Martian missions. missions, experts say.
Despite the findings regarding the kidneys, researchers suggest that short spaceflights do not pose significant health risks to private astronauts.
Other findings indicated that women can physiologically tolerate spaceflight better than men, but further research is needed.
The new research analyzed samples collected from the first all-civilian crew of the SpaceX Inspiration4 mission that launched on September 15, 2021 and returned three days later.
In addition to the damage to the kidneys, the research suggests that the effects of short-term spaceflight mirror those of longer missions.
This includes increased levels of a protein (cytokines) that can lead to excessive inflammation, and elongation of parts of the DNA found at the ends of each of our chromosomes (telomeres) – which can result in mutations.
The study found that although more than 95% of changes returned to normal in the months after the mission, some proteins, genes and cytokines still appeared to be activated during the post-spaceflight recovery period and persisted for at least three months post-flight .
Christopher Mason of Weill Cornell Medicine, New York, USA, one of the authors of the papers published in the Space Omics and Medical Atlas (SOMA) package, said: “It’s actually mostly good news in the sense that there are a lot of changes in all those layers of biology and modalities of biochemistry, but the vast majority of them quickly return to baseline.
“So I think it bodes well for people who are thinking, ‘Maybe in six months I’ll go to space,’ because everyone can get ready to go very quickly, and not only get back and forth safely, but can be trained and just skills and tools to conduct experiments in space very quickly.
Researchers from UCL looked at the effect of spaceflight on the kidneys.
They found that both human and animal kidneys are remodeled by the conditions of space, with specific parts of the organs showing signs of shrinkage after less than a month in space.
Researchers suggest that the likely cause of this is microgravity rather than galactic cosmic rays (GCR), although further research is needed to determine whether the interaction of microgravity and GCR can accelerate or exacerbate these structural changes.
It was previously believed that the main reason kidney stones form during space missions is solely due to microgravity-induced bone loss leading to a buildup of calcium in the urine.
However, the new findings, published in Nature Communications, indicate that the way the kidneys process salts is fundamentally changed by spaceflight and is likely a major contributor to the formation of kidney stones.
The scientists suggest that the most alarming finding is that the kidneys of mice exposed to radiation simulating GCR for 2.5 years experienced permanent damage and loss of function.
They say it will be necessary to develop measures to protect the kidneys from damage if missions to Mars are to be successful.
Dr. Keith Siew, first author of the study from the London Tubular Centre, based at UCL’s Department of Renal Medicine, said: “We know what has happened to astronauts during the relatively short space missions that have been carried out so far, in terms of a increase in the number of health problems such as kidney stones.
“What we don’t know is why these problems occur, nor what will happen to astronauts on longer flights, such as the proposed mission to Mars.
“If we don’t develop new ways to protect the kidneys, I would say that while an astronaut could get to Mars, he might need dialysis on the way back.
“We know that the kidneys only show signs of radiation damage late; By the time this becomes apparent, it will likely be too late to prevent failure, which would be catastrophic for the mission’s chances of success.”
Professor Stephen B. Walsh, senior author of the study from the London Tubular Centre, UCL Department of Renal Medicine, said: “Our research highlights the fact that if you’re planning a space mission, the kidneys really do matter.
“You can’t protect them from galactic radiation through shielding, but as we learn more about kidney biology, it may be possible to develop technological or pharmaceutical measures to facilitate longer space travel.
“Any drugs developed for astronauts could also be useful here on Earth, for example by enabling the kidneys of cancer patients to tolerate higher doses of radiotherapy, with the kidneys being one of the limiting factors in this regard.”
In the Wellcome, St Peters Trust and Kidney Research UK (KRUK)-funded study, the UCL-led team of researchers from more than 40 institutions around the world looked at data and samples from more than 40 low-orbit space missions to the Earth involving humans and mice. as well as 11 space simulations with mice and rats.
The SOMA package, published in Nature, contains data from a range of missions, including the SpaceX Inspiration4, Polaris Dawn, Axiom, NASA Twins and Jaxa missions, and researchers around the world.
In a flagship article, Eliah Overbey, Cem Meydan, Susan Bailey, Afshin Beheshti, Christopher Mason, and colleagues provide a detailed guide to the data.
Speaking about the findings on the differences between men and women, Professor Mason said: “There are a number of things we know that women seem to be less affected by.
“One is the spaceflight-associated neuro-ocular syndrome – or the damage that can occur to their eyes – I think that’s already been established, and I think in this case the genetic and epigenetic resilience is something that we’ve observed here and appears to be a new finding. .
“Maybe it’s just the fact that women have to give birth, so maybe being able to tolerate big changes in physiology and fluid dynamics is great for dealing with pregnancies, but also for managing the stress of spaceflight on a physiological level.
“We don’t yet have the full answer to why women seem to be a little more tolerant of the stressors of space travel so far, but we’re looking into it.”