Space holds secret to slowing down ageing
A study of twin astronauts revealed unexpected changes in chromosomes linked to age and disease
Twin astronauts could have given scientists a valuable clue to slowing down ageing. Researchers monitored Scott Kelly, 51, at the International Space Station and his identical twin Mark on Earth. They found that in space his white blood cells showed changes associated with a longer life.
WHEN Nasa scientists set out to study identical twin astronauts, leaving one on Earth and sending the other to the International Space Station (ISS) for a year, they expected that microgravity would have largely negative impacts.
But on board the ISS, Scott Kelly, 51, experienced a transformation that baffled researchers – the telomeres in his white blood cells became longer.
Telomeres are caps that sit at the end of chromosomes, protecting the DNA inside, like the plastic aglets on the end of shoelaces.
As people age, telomeres shorten and eventually vanish in a process that experts think is linked to diseases such as cancer or heart disease.
Longer telomeres are associated with a longer lifespan, so it appears Kelly was ageing more slowly than his twin, Mark, back on Earth.
The effect wore off when he returned from space after 340 days, but researchers are keen to work out what caused the growth in his telomeres and determine if it could be harnessed to create anti-ageing therapies.
Prof Susan Bailey, of Colorado State University, who tested the twins’ blood, said the telomere lengthening in space was “striking”.
“Telomeres shorten as we get older and they can serve as a biomarker of accelerated ageing or of some of the associated health risks like cardiovascular disease or cancer,” said Prof Bailey.
“We imagined going into the study that the unique kinds of stresses and extreme environmental exposures like space radiation and microgravity would act to accelerate telomere loss.
“It was really quite a surprise to us that what we saw was a very space flight-specific elongation of telomeres. We’re scratching our heads.
“We all worry about getting older, and everyone wants to avoid cardiovascular disease and cancer. I don’t think it can really be viewed as the fountain of youth. But if we can figure out what’s causing changes in telomere length, perhaps we could slow it down.” While most of Scott’s telomeres returned to near pre-flight levels on his return to Earth, he now has more short telomeres than prior to the mission, suggesting he is now at greater risk from disease than his brother.
Previous studies have shown the Apollo astronauts were five times more likely to have died from cardiovascular disease than those who went into low orbit or never left the Earth.
The Twins Study, published in the journal Science, was conducted by 12 universities across the US. Such studies are crucial if astronauts are to travel to Mars or set up a lunar base as is planned by Nasa and other agencies. “We cannot send humans to Mars without knowing how space flight affects the body,” said Dr Fred Turek, of Northwestern University, Illinois, who led the study into changes in the twins’ microbiome, or gut flora.
“The plan is to send people to Mars in 2035, so we cannot wait until 2033 to gain this information.” Scott’s gut flora was largely unaffected, but there were noticeable changes in genes that control bone formation, DNA repair and the immune system.
“We don’t know yet if these changes are good or bad,” said Dr Christopher Mason, an associate professor of physiology and biophysics at Weill Cornell Medicine, who studied DNA changes in the twins. “This could just be how the body responds, but the genes are perturbed, so we want to see why and track them to see for how long.”
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