In a landmark study, a group of USA scientists from Johns Hopkins, Stanford University, and other institutions has found no long-lasting, major differences between the epigenomes of astronaut Scott Kelly, who spent a year in space aboard the International Space Station, and his twin brother, Mark, who remained on Earth. Scott Kelly was certainly affected by the stresses of space but once he got back to Earth, numerous changes his body underwent reversed as if he wasn't in space at all. "We developed the methods for doing these types of human genomic studies, and we should be doing more research to draw conclusions about what happens to humans in space".
And a large, interdisciplinary research team tracked the health and biology of both men, in a groundbreaking attempt to observe the effects of spaceflight on the human body.
Chris Mason, a geneticist at Weill Cornell Medicine, looked at how the unique environment of space impacts genes.
NASA has big ambitions for taking humans into space, including in long-term missions on the Moon and, eventually, to Mars.
Epigenetic changes involve chemical "tweaks" to DNA that can influence gene activity, but the changes don't affect the underlying genetic code itself.
It's unclear what significance these lasting effects will have on the astronaut.
The researchers, echoing what NASA has suggested previously, said the twins study turned up no showstoppers - no shocking health consequences that would surely prevent a human mission to Mars or similar long-duration mission.More news: You'll soon be able to edit Microsoft documents natively on Google Docs
It's also impossible to say whether Kelly's time in space is responsible for the changes documented in the study. Turek and Vitaterna were concerned that Scott Kelly's diet in space, which comprised mostly freeze-dried, irradiated, pre-packaged foods, would decrease the diversity in his microbiome.
The "twins study" used Mark Kelly - a former astronaut who is now running as a Democrat for Senate in Arizona - as the control for a study of the effects of space travel on his brother, who spent nearly a year on the International Space Station in 2015.
"We were surprised, that was the first reaction", said Bailey, when asked how it felt to see the initial findings.
"We need to get outside of low Earth orbit, and we need for the astronauts to spend longer periods of time to really evaluate some of these health effects".
More than 300 biological samples - stool, urine and blood - were collected from the twins at multiple times before, during and after the one year mission.
Overall, they found that about just as many epigenetic changes occurred in earthbound Mark's DNA as occurred in his space-flying twin. Scott Kelly lived on the International Space Station - while his brother lived on Earth - and returned on March 1, 2016. One question often asked is whether Scott will return from space younger than Mark - a situation reminiscent of "Interstellar" or Einstein's so-called "Twin Paradox".
"It was encouraging to see that there was no massive disruption of the epigenome in either Mark or Scott", said Lindsay Rizzardi, who worked on Feinberg's team, in a press release. "But the findings give us clues to what we should examine more closely in future studies of astronauts". "We have corresponding studies of people on Earth who remain relatively stable but when they hit a stress response their immune system just goes off".More news: Dale Steyn rejoins RCB
Feinberg noted some of the logistical challenges of the study.
Even so, the question of spaceflight-associated aging and the accompanying risk of developing age-related diseases like dementia, cardiovascular disease and cancer - during or after a mission - is an important one, and one that we aimed to address directly with our study of telomere length.
Twin Investigators coordinated sample collection and transport from the ISS and also collected samples in Russia when Scott Kelly returned to Earth via the Russian Soyuz spacecraft.
What researchers discovered is pretty reassuring for near-Earth space travel - while Scott's body did undergo some changes compared with Mark, things went back pretty much to normal once he returned home. Not all of the changes disappeared-or at least not quickly-after Scott's return.
About 40% of astronauts experience these sort of vision changes, said Lee. The scientists also observed cognitive changes and increased stress levels in Scott during the flight, which, again, may not be attributed to space flight alone.
"This is the dawn of human genomics in space", he said in a statement.
"The bottom line: There's still a ton we don't know", said Stanford's Snyder.More news: Acer announces ConceptD; company’s new line-up of premium laptops designed for creators