Astronauts standing by a rocket ship

Photo by Mike Kiev from Unsplash

New study shows damage from cosmic radiation, microgravity could be ‘catastrophic’ for human body

LONDON — As humanity sets its sights on deep space missions to the Moon, Mars, and beyond, a team of international researchers has uncovered a potential problem lurking in the shadows of these ambitious plans: spaceflight-induced kidney damage.

The findings, in a nutshell

In a new study that integrated a dizzying array of cutting-edge scientific techniques, researchers from University College London found that exposure to the unique stressors of spaceflight — such as microgravity and galactic cosmic radiation — can lead to serious, potentially irreversible kidney problems in astronauts.

This sobering discovery, published in Nature Communications, not only highlights the immense challenges of long-duration space travel but also underscores the urgent need for effective countermeasures to protect the health of future space explorers.

“If we don’t develop new ways to protect the kidneys, I’d say that while an astronaut could make it to Mars they might need dialysis on the way back,” says the study’s first author, Dr. Keith Siew, from the London Tubular Centre, based at the UCL Department of Renal Medicine, in a media release. “We know that the kidneys are late to show signs of radiation damage; by the time this becomes apparent it’s probably too late to prevent failure, which would be catastrophic for the mission’s chances of success.”

Rocket traveling to Mars
New research shows that exposure to the unique stressors of spaceflight — such as microgravity and galactic cosmic radiation — can lead to serious, potentially irreversible kidney problems in astronauts. (© alonesdj – stock.adobe.com)

Methodology

To unravel the complex effects of spaceflight on the kidneys, the researchers analyzed a treasure trove of biological samples and data from 11 different mouse missions, five human spaceflights, one simulated microgravity experiment in rats, and four studies exposing mice to simulated galactic cosmic radiation on Earth.

The team left no stone unturned, employing a comprehensive “pan-omics” approach that included epigenomics (studying changes in gene regulation), transcriptomics (examining gene expression), proteomics (analyzing protein levels), epiproteomics (investigating protein modifications), metabolomics (measuring metabolite profiles), and metagenomics (exploring the microbiome). They also pored over clinical chemistry data (electrolytes, hormones, biochemical markers), assessed kidney function, and scrutinized kidney structure and morphology using advanced histology, 3D imaging, and in situ hybridization techniques.

By integrating and cross-referencing these diverse datasets, the researchers were able to paint a remarkably detailed and coherent picture of how spaceflight stressors impact the kidneys at multiple biological levels, from individual molecules to whole organ structure and function.

Results

The study’s findings are as startling as they are sobering. Exposure to microgravity and simulated cosmic radiation induced a constellation of detrimental changes in the kidneys of both humans and animals.

First, the researchers discovered that spaceflight alters the phosphorylation state of key kidney transport proteins, suggesting that the increased kidney stone risk in astronauts is not solely a secondary consequence of bone demineralization but also a direct result of impaired kidney function.

Second, they found evidence of extensive remodeling of the nephron – the basic structural and functional unit of the kidney. This included the expansion of certain tubule segments but an overall loss of tubule density, hinting at a maladaptive response to the unique stressors of spaceflight.

Perhaps most alarmingly, exposing mice to a simulated galactic cosmic radiation dose equivalent to a round trip to Mars led to overt signs of kidney damage and dysfunction, including vascular injury, tubular damage, and impaired filtration and reabsorption.

Piecing together the diverse “omics” datasets, the researchers identified several convergent molecular pathways and biological processes that were consistently disrupted by spaceflight, causing mitochondrial dysfunction, oxidative stress, inflammation, fibrosis, and senescence (cell death) — all hallmarks of chronic kidney disease.

Takeaways

This study is a clarion call for the spaceflight community, highlighting the urgent need to prioritize research into spaceflight-associated kidney dysfunction. The findings suggest that without effective countermeasures, long-duration missions beyond Earth’s protective magnetosphere could put astronauts at significant risk of developing chronic kidney problems, with potentially dire consequences for both individual health and mission success.

The researchers stress that their results likely represent a conservative estimate of the true extent of spaceflight-induced kidney injury, given the relatively short mission durations and lower radiation exposures compared to anticipated future deep space missions. They also point out that many of the observed pathological changes, such as fibrosis and loss of functional tissue, may be progressive and irreversible, underscoring the need for early intervention and prevention strategies.

On a more positive note, the study’s integrative pan-omics approach provides a powerful roadmap for future research into the health risks of spaceflight. By identifying key molecular players and pathways involved in spaceflight-associated kidney dysfunction, the findings could guide the development of targeted therapies or preventive measures, such as drugs to protect mitochondrial function, antioxidants to combat oxidative stress, or dietary interventions to support kidney health.

“Our study highlights the fact that if you’re planning a space mission, kidneys really matter,” concludes senior author Stephen B. Walsh, a professor with UCL’s Department of Renal Medicine. “You can’t protect them from galactic radiation using shielding, but as we learn more about renal biology it may be possible to develop technological or pharmaceutical measures to facilitate extended space travel.”

StudyFinds Editor-in-Chief Steve Fink contributed to this report.

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