When space attacks

NASA study: Astro’s immune system went on high alert

WASHINGTON — Astronaut Scott Kelly made himself a guinea pig for all the people who dream of human journeys to Mars and other destinations in space.

In 2015, Kelly rode a rocket into space and spent nearly a year on the International Space Station in low Earth orbit, while his identical twin brother, Mark Kelly, stayed on Earth for NASA’s celebrated “twins study,” designed to see what spaceflight does to the human body.

The full results, published in the journal Science, showed that Scott experienced numerous physiological and chromosomal changes during his long sojourn in orbit, including changes in gene expression. His immune system went on high alert, both when he went to space and upon returning to Earth. His body acted as if it were under attack.

Mark Kelly served as the comparison subject for the experiment. The retired astronaut is married to former congresswoman Gabby Giffords, a Democrat, and is running for the Democratic nomination for U.S. Senate in Arizona.

The researchers, echoing what NASA has suggested previously, said the twins study turned up no showstoppers — no shocking health consequences that would prevent a human mission to Mars or similar long-duration mission. But the report shows anew that the human body is adapted for life on the surface of Earth and goes haywire in zero gravity.

One of the most dramatic findings concerned epigenetics — how genes are turned on or off to produce proteins. Gene expression changed in both Kellys during the study but in significantly different ways. The study found that more than 90 percent of Scott Kelly’s gene expression changes reverted to normal when he returned to the surface.

His telomeres — structures that protect the ends of chromosomes, much like the plastic caps on the ends of shoelaces, and which erode over time as part of the natural aging process — lengthened in space. But that’s no fountain of youth, the study found, because the telomeres shortened dramatically when he to Earth.

Months later, he still showed a slightly elevated number of cells with shortened telomeres, possibly an effect of radiation exposure.

“He might be at some increased risk for cardiovascular disease or some types of cancer,” said Susan Bailey, a biologist at Colorado State University who led one of the investigations in the study.

“Although average telomere length, global gene expression, and microbiome changes returned to near preflight levels within 6 months after return to Earth, increased numbers of short telomeres were observed and expression of some genes was still disrupted,” the report states.

The study found certain cognitive deficits during a battery of tests in orbit, which lingered when Scott Kelly later took tests back on Earth. returned