WASHINGTON (AP) – Almost a year in space, astronaut Scott Kelly's immune system set the alert on alert and changed the activity of some of his genes compared to his Earth-bound twin, researchers said Friday.
Scientists do not know if the changes were good or bad, but the results of a unique NASA twin study raise new questions as the space agency wants to send people to Mars.
Genetic Doppelganger Testing Gives Scientists an Unprecedented Opportunity Track Details of Human Biology; For example, how do the genes of an astronaut turn on and off differently in space than at home? A puzzling change announced on Friday at a science conference: Kelly's immune system was hyperactivated.
"It's as if the body reacts to this alien environment as if you had a mysterious organism in it," said geneticist Christopher Mason of New York Cornell Medicine of York, who led the study. He said that doctors are now looking at other astronauts.
Since the beginning of space exploration, NASA has studied the impact of the bodies of astronauts, such as bone resorption, which requires physical activity. Usually they are in space for about six months. Kelly, who lived on the International Space Station, spent 340 days in space and set a US record.
"I never felt completely normal in outer space," Kelly, now retired, said in an email to The Associated Press. citing the usual congestion due to fluid migration, headaches and difficulty concentrating with additional carbon dioxide and digestive problems from weightlessness.
However, this study was a unique entry into the molecular level, with former astronaut Mark Kelly, Scott's twin, lying on the ground for comparison. Full results have not yet been released, but researchers presented some findings at a meeting of the American Association for the Advancement of Science on Friday.
A number of genes linked to the immune system have become hyperactive, Mason said. It's not a change in DNA, but in so-called "gene expression", as genes turn off and increase or decrease their protein production. Mason also discovered a spike in the blood of another marker that stimulates the immune system. At the same time, Kelly's blood showed less of another type of cell, representing an early defense against viruses.
It's no surprise that gene activity in space is changing – it's changing in response to all sorts of stress.
"You can see how the body adapts to changing its environment," Mason said.
The good news: Shortly after Kelly was back on Earth in March 2016, everything returned to normal. "That memory or need to be on high alert is" even six months later, "Mason said. "It's encouraging overall," said Craig Kundrot, who heads NASA's Space Life and Science research. "There are no important new warning signs. We see changes that we did not necessarily expect, "but do not know if those changes matter.
NASA already knew from four Russians who had been living in outer space for more than a year that they would last longer Time out of the world is possible, Kundrot said, adding, "We also strive for more than just possible. We want our astronauts to do more than just survive. "
Ultimately, NASA's Twin Study gives a catalog of things to watch over future missions to see if other astronauts are reacting the same way, Mason said that astronauts will be able to perform some of these tests in space on future missions, rather than freezing samples for scientists.
Immune problems seem to be familiar to American astronaut Dr. Jerry Linenger, whom he had spent more than four months He said he had never been sick in orbit, but when he returned to Earth, "I was probably sicker than I was in my life."
Astronauts launch their own germs into orbit and become exposed to the germs of her crewmates then after a week with nothing else in the "very sterile environment" of a space station "is your immune system us not required, "Linenger said.
A human mission to Mars that NASA plans to launch in the 2030s, Kundrot said it would take 30 months, including surface time.
Radiation is a major concern. The mission would expose astronauts to galactic cosmic radiation that is beyond NASA's safety standard. It's "just a little over," he said.
On Earth and even on the space station, Earth's magnetic field shields astronauts from much radiation. There would be no such shielding on the way to Mars and back, but tunnels or dirty habitats could help a little on Mars, Kundrot said
Kelly, who will turn 55 next week, said he would go to Mars. He said a long journey "would not be worse than what I've experienced, maybe better, I think the big physical challenge, aside from the radiation, will be a mission where you spend years in space."
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