Scientists got a rare opportunity to see howconditions at the International Space Station affected gene expression by comparing identical twin astronauts: one of them spent about a year in space, the other remained on Earth. The environment on the space station caused changes in gene expression through an epigenetic process. NASA scientists already know that astronauts will be exposed to physical stress in different ways.
Studies of the genetic background of astronauts canexplain why some of them are more prone to health problems when they return to Earth. These results can lead to individual preventive measures for vulnerable astronauts. And what is most surprising, these discoveries can also lead to the development of methods for the treatment of all syndromes affecting us on Earth.
What happens to a man in space: an example of twins
NASA is studying the effects of space travelfor the human body from the very beginning of the space age. At a press conference held about a week after arriving at the International Space Station (ISS), Canadian astronaut David Saint-Jacques said he feels "somewhat overloaded" and "with a large, swollen red face, as if hanging upside down on a crossbar." This uncomfortable feeling is due to the redistribution of fluid from the lower part to the upper body.
Cosmonauts health after long missions
Health effects arising fromthe result of long flights into space are not well understood. In general, astronauts maintain excellent mental and physical health compared with the population, even on return from long-term missions. And yet, the health effects of such missions have been scientifically recognized, including problems with the cardiovascular system and eyesight, the causes of which are being studied.
NASA scientists are exploring how gene expression is howDNA is converted into tissue - changes in response to the influence of the environment on the ISS. The field of epigenetics describes the mechanisms by which environmental factors, such as microgravity, relatively high levels of carbon dioxide and possible jumps of radiation, alter the way DNA is read.
They also want to know how each person’s unique DNAThe astronaut will determine their response to the space station environment. Now, out of 37 studies conducted at the space station, 3 are dedicated specifically to genetic research.
Two sides of the same coin
Preliminary results exceptionalstudies of identical twins support the idea that space travel can affect gene expression in various organs. From 2015 to 2016, astronaut Scott Kelly was on board the ISS for 340 consecutive days. His twin brother Mark remained on Earth. The main genetic code of Scott has not changed, but the environment of the space station influenced how this code was transformed into tissues.
According to one of the leading scientists in thisThe study of Christopher Mason's twins, these changes have occurred in important biological pathways related to bone formation and the immune system. Changes in gene expression were categorized for possible risk as “low, medium or high”.
Changes in low-risk gene expression(about 93% of all changes) returned to normal when Scott returned to Earth. According to Mason, the possible changes from medium to high risk did not change after six months and “they will keep an eye on them.” For example, there were changes in the expression, which led to the formulation of the immune system in the "high alert".
Although the study of identical twins provides the best estimate of the influence of outer space on the expression of genes, there are not so many twin astronauts around.
Confirmation of results in Kelly twinswill require research from other astronauts. Currently, these studies are being conducted at the International Space Station for confirmation, since a liquid biopsy (cell-free DNA and RNA samples from the blood) is collected for analysis. But the experiments with the participation of the twins served as a "springboard for all subsequent research," says Mason.
Missions change their minds
Previous eye health studies in the groupastronauts suggest that not all astronauts will respond equally to life on a space station. Astronaut ophthalmological syndrome is a condition that affects some astronauts. These eye changes are classified by NASA as “a significant risk to space travelers” and include changes in the lens and shape of the eye.
In some cases, astronauts with excellent eyesight.before space flight, “they come back with the need to wear glasses,” says Scott Smith, the leading nutrition biochemist at NASA. "We saw chemical changes in blood samples (from astronauts) before the flight, so we decided to study genetics."
Blood samples were provided for this study.72 astronauts. The analysis showed that the genetic background of each astronaut plays a certain role in determining the vulnerability of their eyes or the epigenetic response to harmful triggers on the space station.
Cosmic eyes and earthworms
The study suggests that someastronauts can be warned about the personal risk of developing vision problems during long space flights. Better yet, apply and implement individual preventive measures for people with the greatest risk of disease.
“Virtually all work at NASA matters to the general public,” says Smith.
Astronaut ophthalmologic syndrome is associated withanother, much more common health problem here on Earth. It turns out that the same genetic variants and changes in serum factors that are associated with eye problems in astronauts are also associated with polycystic ovary syndrome, a form of infertility in women.
Genetic and epigenetic studies onastronauts will provide astronauts with personalized medical approaches in space. And they could provide people on Earth with potential methods of treating complex diseases. These are the preliminary results of the study.
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