Findings from NASA's 'Twins Study'
NASA's landmark "Twins Study", which gave us the first integrated molecular view into genetic changes, has demonstrated that a human body adapts and remains robust and resilient even after spending nearly a year aboard the International Space Station (ISS).
The findings, published in the Science journal, will help NASA keep astronauts healthy during deep space exploration as the US space agency goes forward to the Moon and journeys onward to Mars.
As part of the "Twins Study" conducted from 2015-2016, NASA astronaut Scott Kelly spent a year in space while Mark, his identical twin, stayed on Earth as a control subject to look at the effects of space travel on the human body.
"The 'Twins Study' has been an important step toward understanding epigenetics and gene expression in human spaceflight," said J.D. Polk, chief Health and Medical Officer at NASA Headquarters, in a statement.
The findings showed that the telomeres in Scott's white blood cells, which are biomarkers of ageing at the end of chromosomes, were unexpectedly longer in space then shorter after his return to Earth with average telomere length returning to normal six months later.
In contrast, Mark's telomeres remained stable throughout the entire period, NASA said.
Further, Scott's immune system responded appropriately in space. For example, the flu vaccine administered in space was found to work exactly as it does on Earth.
Scott participated in a number of biomedical studies, including research into how the human body adjusts to known hazards, such as weightlessness and space radiation, while Mark participated in parallel studies on Earth to help scientists compare the effects of space on a body down to the cellular level.
The findings, published in the Science journal, encompass work from 10 research teams and represent 27 months of data collection.
Another significant finding is the variability in gene expression, which reflects how a body reacts to its environment and will help inform how gene expression is related to health risks associated with spaceflight.
While in space, researchers observed changes in the expression of Scott's genes, with the majority returning to normal after six months on Earth.
However, a small percentage of genes related to the immune system and DNA repair did not return to baseline after his return to Earth.
