New insights into the health effects of long-duration spaceflight – 30 scientific papers by over 200 researchers

History NASA Twins Study studied identical twin astronauts Scott and Mark Kelly and provided new information on the health effects of spending time in space.

Colorado State University professor Susan Bailey was one of more than 80 scientists from 12 universities who researched the textbook experiment; Mark remained on Earth while Scott was in orbit above for almost a year. The massive effort was coordinated by NASA’s human research program.

Bailey continued his research at NASA and now joins more than 200 researchers from dozens of academic, government, aerospace, and industry groups to publish a set of 30 scientific papers in five Cell Press journals on November 25, 2020.

Jared Luxton, who recently received his doctorate in cellular and molecular biology from CSU, is the first author of two of these studies. He is now a data scientist at the US Department of Agriculture in Fort Collins.

The research – including a comprehensive article that covers what investigators have learned about the fundamental characteristics of space flight – represents the largest data set on space biology and the effects on astronaut health ever produced.

For Bailey, it is also a milestone marking many years of work with NASA, which included his primary role in basic radiation studies and the honor of being selected as a researcher for the Twins study and concurrent research projects involving astronauts. During this time, several graduate students from his lab earned doctorates under his mentorship.

“We now have a foundation to build on – things we know to look for in future astronauts, including changes in telomere length and DNA damage responses, ”Bailey said. “Going forward, our goal is to get a better idea of ​​the underlying mechanisms, what happens during long-duration spaceflight in the human body, and how it varies between people. Not everyone responds the same. This was one of the advantages of having the largest cohort of astronauts in these studies.

Studying the ends of chromosomes, with implications for aging

Bailey is an expert in telomeres and radiation-induced DNA damage, areas of research that were of keen interest around the world when the Twins Study was published. In this study, she and her team found that Scott’s telomeres in his white blood cells elongated in space, then returned to an almost normal length after he returned to Earth.

Telomeres are protective “caps” at the ends of chromosomes that get shorter as a person ages. Large changes in telomere length could mean that a person is at risk for accelerated aging or for diseases that accompany aging, cardiovascular disease and cancer for example.

As part of the latest research, Bailey, Luxton, Senior Research Associate Lynn Taylor, and her team studied a group of 10 independent astronauts, including CSU alum, Dr. Kjell Lindgren, comparing the results with the results of the Kelly twins. Researchers did not have access to in-flight blood and other samples for all crew members, but Bailey said they had before and after space flight blood samples for everyone.

The investigations involved astronauts who spent about six months on the International Space Station in low Earth orbit, which is shielded from certain space radiation. Despite the protection, scientists have 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 flights contributed to the lengthening of telomeres they observed. They also found that astronauts in general had shorter telomeres after space flight than before. The team also observed individual differences in responses.

To better understand these findings, Bailey’s team also studied twin climbers who climbed Mt. Everest, an extreme environment on Earth. The non-climbing twins stayed at a lower elevation, including in Boulder, Colorado. Remarkably, the team found similar evidence of oxidative stress and changes in telomere length in climbers.

Christopher Mason, associate professor at Weill Cornell Medicine and co-author with Bailey, performed gene expression analyzes on Mt. Everest climbers. He found evidence of a telomerase independent pathway based on telomere length maintenance recombination known to result in longer telomeres.

Bailey said that when chronic oxidative stress occurs, it damages telomeres.

“Normal blood cells die and try to survive,” she says. “They adapt to their new environment. Some cells will activate an alternate pathway to keep their telomeres running. It’s similar to what happens with some tumors. Certain cells emerge from this process. This is what we think we see during spaceflight as well.

Luxton said the mechanism described above – known as alternating telomere lengthening, or ALT – was an unexpected discovery.

“You usually see that in cancer or in developing embryos,” he says.

Take care of your telomeres

Similar to the findings of the Twins Study, Bailey said the new findings have implications for future space travelers establishing a base on the Moon or traveling to March, or even as a space tourist. Long duration exploration missions will involve an increase in time and distance outside the protection of Earth.

While longer telomeres in space may seem like a good thing, perhaps even a “fountain of youth,” the scientist said she suspected a somewhat different ending to the story.

“The extended lifespan, or immortality, of cells that have suffered DNA damage induced by space radiation, such as chromosome inversions, is a recipe for an increased risk of cancer,” he said. she declared.

Bailey said she and the team observed an increase in frequencies of reversals among all crew members, during and after space flight.

“Telomeres really reflect our lifestyles – whether it’s on the planet or anywhere else,” Bailey said. “Our choices make a difference in the speed and quality of our aging. It is important to take care of your telomeres. “

Bailey is a principal author of:

• “Fundamental Biological Characteristics of Space Flight: Advancing the Ground to Enable Deep Space Exploration” to appear in Cell.
• “Temporal Telomere and DNA Damage Responses in the Space Radiation Environment”, to appear in Cell reports.
• “Telomere Length Dynamics and DNA Damage Responses Associated with Long-Duration Spaceflight, which will also be published in Cell reports.

Bailey and Luxton are also co-authors of “Haplotype Diversity and Sequence Heterogeneity of Human Telomeres”, which will be published in Genomic research.