Astronaut Scott Kelly spent a year in space during which suffered physical, molecular and cognitive changes, but most of the variables remained stable or they returned to their base level after six months on Earth, According to a study published in the journal Science and collected by the agency Efe.
The «Twins study» not only allowed to analyze the changes experienced by Scott for 340 days on the International Space Station (ISS) between 2015 and 2016, but also could compare with his twin brother, Mark, who remained on Earth, which is a very special.
The results "do not point to significant differences" in Scott's health, said experts from twelve universities, who formed ten teams to do as many studies covering aspects such as physiology, behavioral health, genomics or metabolism.
Furthermore, "given that most of the biological and human health variables remained stable or returned to the base level, these data suggest that human health can be maintained for the most part during this period (one year) of flight space, "according to a note by the American University of Texas.
Risks associated with space flight include exposure to radiation and microgravity, but until now it was not clear how they affect health during extended stays.
Today astronauts retired from NASA were subjected to numerous controls before, during and after the mission of Scott, who was 52 years old, whose samples were sent to Earth, fresh or frozen.
The experts identified changes such as decreased body mass, telomere lengthening, genome instability, distention of the carotid, alteration of ocular structure and microbiota, and some limited decline in cognitive performance, although a large part of these parameters returned to normality at home.
The biologist and genomist Mike Snyder of Standford University said in a telephone press conference, along with other responsible for the study, that "it is reassuring to know that when you return home, things will be, to a large extent, as before."
When the body is faced with a stressful environment it undergoes changes, "for example the immune system is activated", but "it is good to know that you can still function well, that things continue to function normally (...) and that everything will return to The normality".
However, it is not known if any of the persistent changes are solely related to the space stay or how long they will last.
The immune system, according to preliminary data, responds appropriately in space, just as it does on Earth, in case a vaccine is needed - the flu was tested - during a long-term mission.
The team analyzed the telomeres (located at the ends of the genes and responsible for protecting their integrity), whose length has to do with aging and some associated risks such as cardiovascular disease or cancer.
The head of the team that analyzed age-related biomarkers, Susan M. Bailey of Colorado State University, said that "it was really surprising" to note that telomere lengthening occurred during the space stay.
Bailey joked that the lengthening of telomeres "Can not be seen as a source of youth and that people can expect to live longer because they are in space ", especially because after the return they suffered" a rapid shortening ".
Space flights, according to experts, are associated with stress due to lack of oxygen, increased inflammation and drastic changes in nutrients that affect gene expression.
Although Scott's DNA was not altered, changes in gene expression were noticed - the process by which DNA instructs cells to produce components such as proteins - especially those related to the immune system.
These changes can be attributed to Scott's stay in space, because although his brother also experienced modifications, they were not the same.
In any case, more than 90% of the genes that changed their activity levels "returned to normal" six months later, said a statement from Johns Hopkins Medicine.
The experts agreed in highlighting the importance of these results as a roadmap on the supposed health risks in future long-term space flights, for example to Mars, although they have their limitations due to the small size of the sample, so it is necessary to carry out more studies.
Andrew P. Feinberg, of the Johns Hopkins University, recalled that the study is published on the 58th anniversary of the first human space flight and highlighted the spirit of collaboration among so many scientists in this case, which was "an incredible journey" for them. EFE