Astronauts are experiencing these key changes in space that could impact their health, new research finds

Risks of deep space missions

The six molecular changes that occur during spaceflight include DNA damage, oxidative stress, alterations in telomere length, changes in the microbiome, mitochondrial dysfunction, and gene regulation.

Oxidative stress occurs when free radicals overwhelm antioxidants in a cell, encouraged by the space environment. This type of stress was found to be largely related to other molecular changes the researchers observed.

These changes at the cellular and molecular level can have a significant impact on the health of astronauts, both during and after their missions. These impacts have been observed on the cardiovascular, central nervous, musculoskeletal, immune and gastrointestinal systems, as well as disturbances in circadian rhythms and changes in vision.

Increased cancer risks have also been associated with these changes.

One of the new studies also identified clonal hematopoiesis, when blood cells with mutations spread faster than others, as a potential risk in astronauts for cardiovascular disease, lymphoma and leukemia. Clonal hematopoiesis has been identified in blood samples from astronauts 20 years before middle age when normally detected at 70, compared to 157 cancer patients.

So far, missions to the space station have not exceeded one year, but missions in deep space to Mars could last up to five years.

“Understanding the health implications of the characteristics (6) and developing effective health countermeasures and systems are key steps in enabling humanity to reach the next stage of space exploration,” the authors wrote at the outcome of their study on the effects of spaceflight.

DNA damage

Telomeres act like plugs at the ends of chromosomes to protect them, and they get shorter as people get older.

During the twin study, the telomeres in Scott’s white blood cells actually grew longer in space and returned to normal length after he returned to Earth.

In a new study, the blood samples of 10 astronauts taken before and after the space flight were studied and compared to the results of the Twins study.

Although these astronauts were shielded from some space radiation during their six-month stays on the space station since it is in low earth orbit, researchers have always spotted evidence of damage to their DNA.

Astronaut telomeres lengthened in space due to chronic oxidative stress experienced during space flights. When they returned to Earth, their telomeres were shorter than before the space flight.

“We now have a foundation to build on – things we know how to look for in future astronauts, including changes in telomere length and responses to DNA damage,” said Susan Bailey, author of three of the studies and professor at Colorado State University, in a statement. .

“Going forward, our goal is to get a better idea of ​​the underlying mechanisms, what happens during long-duration spaceflight in the human body, and how it varies between people.

Bailey, an expert in radiation damage to DNA and telomeres, was also an investigator for the Twins Study.

While longer telomeres may appear to be a benefit of space travel, Bailey suspects that this effect could lead to other risks rather than serving as a fountain of youth.

“The extended lifespan, or immortality, of cells that have suffered DNA damage induced by space radiation, such as chromosome inversions, is a recipe for an increased risk of cancer,” Bailey said. “Telomeres really reflect our lifestyles – whether on or off the planet. Our choices make a difference in the speed and quality of our aging. It is important to take care of your telomeres. ”

It’s all in the mitochondria

Health issues specific to astronauts include muscle and bone loss, heart and liver problems, and dysfunction of the immune system.

Now, researchers believe these issues are rooted in a larger problem called mitochondrial dysfunction.

Mitochondria are the powerhouses that generate chemical energy for cells. And when exposed to gravity or altered radiation, they essentially malfunction.

“What we have discovered time and time again is that something is going on with the regulation of the mitochondria that is throwing everything wrong.”

Their study included data from the Twins Study, animal studies, and samples from 59 astronauts.

When mitochondria are removed, ripple effects can be seen in the liver, other organs, and in the immune system. Researchers believe that this dysfunction could also explain the problems astronauts encounter with disturbed circadian rhythms (body clock) and even cardiovascular problems.

Understanding the root of the problem could help researchers target it.

“There are already many drugs approved for various mitochondrial disorders, which would make it easier to move them to this application,” Beheshti said. “The fruit at hand now would be to test some of these drugs with animal and cell models in space.”

Heart stress in space

A study using fruit flies born on the space station, which means they spent half their lives in space, found their hearts to be smaller and less efficient at pumping blood. And if astronauts live on the moon or on the surface of Mars for a long mission, they can experience something similar.

“For the first time, we can see the cellular and molecular changes that may underlie heart disease seen in astronaut studies,” said Karen Ocorr, study co-lead author and assistant professor in the program. development, aging and regeneration at Sanford. Burnham Prebys Medical Discovery Institute, in a statement.

“We started this study to understand the effects of microgravity on the heart, and now we have a roadmap that we can use to start developing strategies to keep astronauts’ hearts strong and healthy.

The hearts of fruit flies are similar to those of humans when we are in the womb. The flies were sent back to Earth and their heart function tested by seeing how they fared as they climbed the side of a test tube.

“In normal fly heart, muscle fibers work like your fingers when they squeeze a tube of toothpaste. In space flies, the contraction was like trying to squeeze the toothpaste out by pressing down instead of squeezing,” he said. Ocorr said. “For humans, this could become a big deal.”

The benefits of understanding how the human heart works in space could help those with heart problems on Earth – and those planning future space missions.

“As we continue our work to establish a colony on the Moon and send the first astronauts to Mars, it is imperative to understand the effects of the extended duration of microgravity on the human body,” said Sharmila Bhattacharya, author of the study and senior scientist at NASA. A declaration.

“Today’s results show that microgravity can have dramatic effects on the heart, suggesting medical intervention may be required for long-term space travel, and point to several directions for therapeutic development.”