Astronaut twins study shows space travel causes premature aging

Those images of a robust Star Trek Captain James T. Kirk beaming around the solar system at maximum warp, or an irreverent Han Solo with his sidekick Chewbacca bustling through space on a quest to save Princess Leia, are sadly, an illusion.

The truth of the matter is that humans or any other living thing — be it a plant or a fruit fly from planet Earth — are not meant for space travel. Traveling in space is very hard on creatures, producing physiological effects similar to premature aging.

That’s one of the reasons the Stein Institute on Aging at UC San Diego brought NASA affiliate Brinda K. Rana, Ph.D., to speak to a packed audience of mostly older adults at the Garren Auditorium of the UCSD School of Medicine, last week.

Rana, who has been the Principle Investigator (PI) on three NASA studies, spoke at length about the effects of space travel on all aspects of the human body — everything from vision to genetics.

“Everything I say has to be approved by NASA. I have to be very careful about the data I reveal,” Rana wryly explained. Her chief NASA project was a comprehensive medical study of twin brother astronauts — Scott and Mark Kelly — who spent different lengths of time in space.

Since the brothers are genetically identical, researchers thought they could ferret out the effects of time in space on their bodies. Mark had 54 days in space, while Scott spent 365 days living on the space station.

Rana headed up a team of scientists from UCSD, one of 10 university-based teams from around the world chosen by NASA to study the astronauts. It was a difficult assignment requiring a great deal of cooperation. For instance, all 10 teams had to share just one vial of blood among themselves from each of the two astronauts.

Rana explained that space travel impairs blood and lymph circulation, especially to the lower parts of the body: Your face gets puffy and your legs get weak. “Space travel is like hanging upside down for a long time!” she said.

That’s why astronauts have to be helped out of their space capsule when they return to Earth. They can’t stand up on their own because their legs are so weak due to poor circulation.

NASA knows that space travel, specifically spending time in zero gravity, is hard. But since the plan is to send men and women up to Mars, which is a six-month flight one way, it is trying hard to develop ways to counteract the debilitating aspects of space travel so the astronauts can function when they get to the red planet. Luckily, the gravity on Mars is less than it is on Earth, so they should be able to stand up and carry out their activities.

Space travel also produces bodily changes you cannot see, affecting the chemistry and physiology of the body. It also affects DNA and RNA. Rana found that while in space, astronaut Scott Kelly had 200,000 differences or mutations in RNA actions, which returned to normal when he came back to Earth. “This just shows that genes are not static, but very sensitive to the environment around us,” Rana said.

Space travel also changes the intestinal flora or probiotics in the gut, which aid digestion. There are also cardiovascular changes, muscular atrophy, arteriosclerosis, glaucoma and bone loss. It looks just like the signs of aging!

Space travelers also experience increased cranial pressure. There are changes to the eyes and vision problems develop. This syndrome is known as “VIIP” or Visual Impaired Intracranial Pressure syndrome.

Rana is an associate professor in the Department of Psychiatry at UCSD and has a lab at the Stein Institute of Aging. She is an alumna of UCSD with a B.A. in math from Revelle College. She also has an M.S. in math from the University of Illinois Urbana-Champaign and a Ph.D. from the University of Texas in molecular genetics. At the Stein Institute, her chief duty is to look for the genes that seem to keep some older adults from getting age-related disorders.

Rana’s NASA studies are relevant because the results have an application to understanding aging on Earth and in helping people in similar situations to space travel, like those who are bedridden for long periods of time. In one experiment, Rana’s lab studied people who were confined to bed with their body inclined downward toward the head at a 15-degree angle, mimicking the effects of space flight.

Karen Ocorr, Ph.D., was at the lecture because she is also working with NASA. Ocorr is a professor in the Development, Aging and Regeneration Program at the Sanford Burham Prebys Medical Discovery Institute on North Torrey Pines Road.

Ocorr studies the ion channels responsible for the relaxation of the human heart, which she says is similar in fruit flies. She just got back a batch of fruit flies that were flown to the space station on the SpaceX CRS-11 mission. She is looking at the effects of zero gravity on their heart function, which can provide models to help understand the human heart. “The fruit flies aren’t doing too well after their space flight,” she confided.

Einstein once predicted that if we start to travel faster in space and get closer to the speed of light, which is about as fast as we could ever go, time will slow down. Thus we would age slower (happy thought!) in terms of chronology. But if we are in zero gravity at light-speed our bodies will age faster (unhappy thought!). Professor Rana says not to worry. “NASA will figure it out!”

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