A new study led by nephrologists at University College London (UCL) reveals that long-duration spaceflight could permanently damage astronauts' kidneys. An alarming observation which seriously complicates plans for manned missions to the red planet.
Space, a hostile environment for the human body
It is well known that space is not a welcoming place for human beings. In addition to the absence of breathable air and drinking water, extreme temperatures and cosmic radiation put a strain on the astronauts' bodies.
Decades of space exploration have highlighted numerous deleterious health effects of spaceflight:
And the longer the mission goes on, the worse these problems become, raising serious challenges for travel plans to faraway destinations like Mars.
The kidneys, unsuspected victims of spaceflight
UCL researchers have identified a new challenge for long-duration missions: the impact of spaceflight on kidney health. Their work, published in the journal Nature, shows that astronauts' kidneys could suffer irreversible damage, to the point of requiring dialysis upon returning from a trip to Mars.
According to Keith Siew, a nephrologist at UCL and lead author of the study, the effects of space radiation on the kidneys have been little studied since the end of the space race. However, doctors know from experience that these organs are particularly sensitive to radiation, to the point of limiting the doses of radiotherapy administered to cancer patients.
The crucial role of the kidneys in the body's balance
The kidneys play a central role in the formation of kidney stones and bone loss, two major problems seen in astronauts. They are responsible for filtering the blood and regulating the amount of fluids in the body. Any malfunction can lead to the formation of stones or other pathologies.
For Norio Suzuki, a space medicine researcher at Tohoku University in Japan, understanding the effects of space on the kidneys is key to developing preventive medicine for future space travelers, not just healthy celebrities.
Worrying changes in astronauts' kidneys
By analyzing biological samples from humans, mice and rats who stayed on the International Space Station (ISS), researchers observed several major changes in the astronauts' kidneys:
It appears that not only do astronauts lose calcium due to weakening of their bones, but they also have a harder time eliminating this excess calcium in their kidneys, leading to the formation of kidney stones.
Ways to protect the kidneys in space
Although the exact causes of these changes remain to be elucidated, the authors put forward several hypotheses. Changes in blood pressure due to weightlessness could overload the kidneys, while radiation is almost certainly a major aggravating factor.
To combat these harmful effects, researchers are considering several avenues:
One thing is certain: future manned missions to Mars will have to carry in their luggage something to preserve the health of the kidneys of their precious passengers. Because if space exploration constantly pushes the limits of humanity, it must not sacrifice the health of those who dare to venture into the cosmic immensity.
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