Key ageing processes appeared to reverse when astronaut Scott Kelly lived on the ISS
Mark and Scott Kelly are the only twins that have ever traveled to space — and their experience will be invaluable if we want to get to Mars one day.
An astronaut who lived in space for just under a year appeared to temporarily reverse his ageing processes, according to brand new research. Scott Kelly, who spent 340 days on the International Space Station between 2015 and 2016, had noticeable mutations in his DNA that appeared to fly in the face of scientific expectations.
One group of investigators looked within Scott’s white blood cells and specifically at his telomeres, which appear at the end of chromosomes. These are known to decrease in length as a person gets older, yet radiation biologist Susan Bailey found the astronaut’s telomeres had actually increased while he was in space. They ended up being longer than those of his twin brother, Mark, who had spent the entire period with his feet firmly on Earth. “That is exactly the opposite of what we thought,” Bailey says.
She believes the change could be linked to Scott’s increased exercise and reduced diet while on board the International Space Station. The telomeres began shortening once more when he returned, however. NASA also says that telomerase activity also increased in both Scott and Mark Kelly last November. This relates to an enzyme that repairs the telomeres and lengthens them, and Bailey believes that this may have been caused by a particularly stressful event in both the twins’ lives at that time. If, however, being in space for a significant amount of time does appear to reverse ageing in some way, it would be of major importance for long duration missions.
Another research group, from Northwestern University, have been focusing on the changes to Scott’s gut microbiome, the thousands of microbe species that live inside the GI tract and help with digestion. And they’ve found an interesting divergence between the two brothers’ bacteria, though they aren’t sure what these changes mean just yet.
Based on stool samples from the twins, the Northwestern team found that there was a sustained shift in the balance between two major groups of bacteria — Firmicutes and Bacteroidetes — in Scott’s gut while he was in space. Meanwhile, his brother Mark only experienced minor fluctuations in this balance during the same time period. Once he returned to Earth, though, Scott’s bacterial balance went back to the way it was before the mission.
The preliminary findings are a result of NASA’s Human Research Program and, more specifically, the Twins Study. Mark, a retired astronaut, was the ground-based control for the experiments and biological samples from both brothers are still being studied by ten researchers, who are keen to discover the effects an extended time in space can have on the body.
Mathias Basner’s study of cognitive performance, for example, found Scott suffered a slight decrease in speed and accuracy post-mission but that the difference between spending six or 12 months in space is negligible. There also appeared to be a decline in bone formation during Scott’s final six months in orbit, although there was good news in relation to a flu vaccine: jabs for each twin showed an increase in T cell receptors, which was the expected immune response. Chemical modifications to Scott’s DNA were seen to decrease while he was in space, however, indicating that genes are very sensitive to a changing environment.
There are also other differences in the twins' DNA. However, it seems that it cannot all be chalked up to Scott's living arrangements for the year in the ISS. NASA found that there are hundreds of unique genetic mutations for both Scott and Mark.
The results are also at its preliminary stage. The Twins Study is expected to have a "joint summary publication" later in the year, where researchers can publish their findings in scientific journals.