Professor Susan Bailey and Dr. Kjell Lindgren, NASA astronaut, during a visit to Bailey’s laboratory in 2016. Lindgren is a graduate of Colorado State University. Credit: CSU Photography
The historical NASA The twin study examined identical twin astronauts Scott and Mark Kelly and provided new information on the health effects of being in space.
Susan Bailey, a professor at Colorado State University, was one of more than 80 scientists at 12 universities who researched the textbook experiment. Mark stayed on earth while Scott orbited high above for almost a year. The massive effort was coordinated by NASA’s Human Research Program.
Continuing her NASA research, Bailey is publishing a package of 30 scientific articles in five Cell Press journals on November 25, 2020 along with more than 200 researchers from dozen of academic, government, aerospace, and industry groups.
Jared Luxton, who recently received a PhD in cell and molecular biology from CSU, is the first author of two of the studies. Today he is a data scientist at the US Department of Agriculture in Fort Collins.
The research – including an overarching paper covering what researchers have learned about the fundamental characteristics of space travel – represents the largest set of data on space biology and astronaut health effects ever created.
For Bailey, this is also a milestone in a longstanding collaboration with NASA, which included her leadership role in fundamental radiation studies and the honor of being selected as a researcher for the twin study and for concurrent research projects with astronauts. During this time, several PhD students completed their PhDs in her laboratory under her supervision.
“We now have a foundation to build on – things to look for in future astronauts, including changes in telomere length and DNA Damage Reactions, ”said Bailey. “Our goal is to get a better idea of the underlying mechanisms in the future, of the processes during long-term space travel in the human body and of the differences between people. Not everyone reacts the same. That was one of the good things about having the larger cohort of astronauts in these studies. ”
Studying the ends of chromosomes with implications for aging
Bailey is an expert on telomeres and radiation-induced DNA damage, areas of research that were of great interest around the world at the time the Twins study was published. In that study, she and her team found that Scott’s telomeres in his white blood cells lengthened in space and then returned to near normal length after he was back on Earth.
Telomeres are protective “caps” at the ends of chromosomes that shorten with age. Large changes in telomere length can put a person at risk for accelerated aging or the diseases that go along with aging, such as cardiovascular disease and cancer.
In the latest study, Bailey, Luxton, Senior Research Associate Lynn Taylor and the team examined a group of 10 unrelated astronauts, including CSU alum Dr. Kjell Lindgren, and compared the results with the results of the Kelly twins. The researchers did not have access to blood and other in-flight samples for all crew members, but Bailey said they had blood samples for all of the blood samples before and after the space flight.
The research involved astronauts who had spent approximately six months on the International Space Station in low-earth orbit that is protected from space radiation. Despite the protection, scientists found evidence of DNA damage that could be warning signs of potential health effects.
New discovery of oxidative stress
Among the new findings, the research team found that chronic oxidative stress during space travel contributed to the observed telomere stretching. They also found that post-space travel astronauts generally had shorter telomeres than before. The team also observed individual differences in responses.
To learn more about these results, Bailey’s team also examined two climbers climbing the mountain. Everest, an extreme environment on earth. The non-climbing twins stayed lower, including in Boulder, Colorado. Notably, the team found similar evidence of oxidative stress and changes in telomere length in the climbers.
Christopher Mason, associate professor at Weill Cornell Medicine and co-author with Bailey, conducted gene expression studies on the Mt. Everest climber. He found evidence of a telomerase-independent, recombination-based route to maintaining telomere length that is known to result in longer telomeres.
Bailey said chronic oxidative stress damages telomeres.
“Normal blood cells die and try to survive,” she said. “They adapt to their new surroundings. Some cells activate an alternative way to keep their telomeres going. It’s similar to some tumors. Some of the cells arise from this process. We believe we can see that during space travel as well. ”
Luxton said the mechanism described above – known as alternate telomeres elongation, or ALT – was an unexpected finding.
“You usually see that in cancer or in embryo development,” he said.
Take care of your telomeres
Similar to the conclusions drawn from the Twins study, Bailey said the new findings have implications for future space travelers who base or travel to the moon Marsor even as a space tourist. Long-term exploration missions require more time and distance outside the protection of the earth.
Although longer telomeres could be a good thing in space, maybe even a “fountain of youth”, the scientist suspects a slightly different ending to the story.
“Increased lifespan or immortality of cells that have suffered DNA damage from space radiation, such as chromosome inversions, is a recipe for increased cancer risk,” she said.
Bailey said she and the team had seen an increased frequency of inversions in all crew members during and after the spaceflight.
“Telomeres really reflect the way we live – whether on or off the planet,” said Bailey. “Our decisions make a difference in how quickly or how well we age. It is important to take care of your telomeres. ”
Bailey is a senior writer on:
- “Basic Biological Characteristics of Space Travel: Advancing the Field to Enabling Space Exploration,” published in cell.
- “Temporal Telomere and DNA Damage Responses in the Space Radiation Environment,” published in Cell reports.
- “Telomere length dynamics and DNA damage responses associated with long-duration space flights, which are also published in Cell reports.
Bailey and Luxton are also co-authors of Haplotype Diversity and Sequence Heterogeneity of Human Telomeres to be published in Genome research.
