Biomedical Science at the ‘Final Frontier’
April 2016—Fascinated by space missions since he was a boy, Andy Feinberg’s dreams of going to space haven’t come true yet, but he has gotten a lot closer than most of us: Last September, he experienced weightlessness aboard NASA’s infamous “Vomit Comet,” for science. Unexpectedly, his big chance didn’t result from years of studying rockets or celestial bodies, but from his studies of how the environment influences gene activity.
Now, Feinberg hopes to learn something about how long-term residence in space affects the human body by comparing biological samples from astronaut Scott Kelly — who recently returned from a year aboard the International Space Station (ISS) — with those of his Earth-bound twin, Mark. The results of Feinberg’s studies on gene regulation may help NASA protect the health of astronauts on ever longer missions, and his weightlessness experiments will ease the way for future biomedical studies in space.
An Extraterrestrial Environment
It’s well-known that our surroundings and habits affect our health — living in a polluted environment can make us sick, and so can smoking. But what about eating dehydrated food for a year? Or floating inside an enclosed structure without gravity to force our muscles into action? With NASA planning to send astronauts to Mars someday — a round trip of at least two and a half years — these are crucial questions to answer. But NASA’s expertise isn’t medicine, so the agency solicited help, and Feinberg responded. The mission? To study how a year in space affects Scott Kelly’s biology, with his twin brother as the control.
“Twin studies are critical to understanding how the environment affects gene function because we can rule out the effect of gene sequence variants on any observed differences,” says Feinberg, director of the Center for Epigenetics, the field that focuses on how gene sequences are controlled. “We can’t learn widely applicable health information from a single pair of twins, but we should be able to find factors where the brothers were similar before Scott left, changed over the course of the year he was gone and then came back to baseline when he returned.”
Feinberg adds that they won’t be able to pinpoint what part of Scott’s space experience — zero gravity, diet, radiation, isolation or something else —caused the detected changes, but there will likely be clues based on what we already know about biology. And future astronauts and those in charge of their medical care will know what to expect from a long mission.
NASA recruited 10 laboratories to analyze all kinds of biological samples taken every three months from each twin before, during and after Scott’s time in space. Other labs will study gut bacteria from stool samples and the array of proteins and chemicals contained in urine samples, for example. Feinberg and postdoctoral fellow Lindsay Rizzardi will extract DNA from blood, saliva and cheek cells.
They will start their analysis once the last sample, six months post-return, has been collected. Rizzardi will look for changes in the patterns of chemical tags, called methyl groups, which attach to DNA and alter the activity of genes. For example, to fix extra breaks in DNA strands caused by increased radiation exposure, there might be changes near genes for DNA repair proteins. Feinberg and Rizzardi hope their results, combined with those from other labs, will shed light on coping mechanisms the body uses to survive life in space.
Logistics, to the Nth Degree
More data from more astronauts would lead to more insights on the effects of space, and Feinberg wants to do what he can to encourage the regular collection of biological samples from astronauts. “Once you start working with NASA, you feel like you’re part of the greatest science experiment ever. Everyone is part of the same mission, one that preceded you and will continue long after you’re gone,” he says.
Astronauts Mark and Scott Kelly
But to make that vision a reality, researchers will have to overcome one of the biggest hurdles to the Twins Study: the logistics of an astronaut collecting biological samples in space and getting them safely back to Earth to be processed and stored.
“Ideally, Scott would have collected his blood samples, centrifuged them, added glycerol to keep the white blood cells intact and frozen them on the ISS until he returned,” says Feinberg. “But the ISS wasn’t stocked with the equipment needed, and we didn’t even know if it would work at zero gravity.”
So NASA had to coordinate shuttle trips to the ISS every three months to pick up the samples so that they could be processed on Earth within 24 to 36 hours of their collection. “Overnighting” a package on a Russian Soyuz shuttle is exceedingly expensive, and that was just the first part of its journey: the Soyuz landed in Kazakhstan, and then a jet flew the samples to Houston, where they were processed, frozen and sent to labs around the country for storage.
To smooth future missions, Feinberg and Rizzardi developed extensive protocols, specifying every detail they could imagine, down to the weight of each item needed for astronauts to process their own samples in space. After getting approval from NASA, they tested the protocols on the “Vomit Comet,” a specially equipped plane that repeatedly climbs from 24,000 to 32,000 feet and then dives down to 24,000 feet again, all in reserved airspace over the Gulf of Mexico. On the way up, passengers experience nearly twice the pull of gravity; on the way down, weightlessness. Each phase of the cycle lasts about half a minute.
To Rizzardi, “it didn’t feel like we were going anywhere. It just felt like lots of pressure changes. Gravity on. Gravity off. Gravity on. Like a light switch.”
“I was in heaven,” says Feinberg, who was lucky not to be hit with nausea like Rizzardi. “It was unlike any other experience. You feel completely disconnected from the Earth without any frame of reference. Even your insides don’t feel particularly connected.”
After they became accustomed to the process, Feinberg and Rizzardi began their experiments. Prior to takeoff, they had set everything up on board, mindful that what wasn’t strapped down, taped or Velcroed would end up floating. They brought blood samples, glycerol, sample containers, pipettes and tips. Pipettes are syringelike instruments found ubiquitously in biomedical laboratories. By depressing a piston on top, liquid is drawn up through disposable tips in precise amounts, determined by the user. Their questions were whether accurate pipetting is possible at zero gravity and whether a watery liquid and a gooey liquid (blood cells and glycerol) can be mixed together at zero gravity. The answer to both turned out to be yes.
“Figuring out that you can pipette in space and preserve cells in glycerol lays the groundwork for astronauts to do all of that themselves on future missions,” says Feinberg. “My hope is that it’s a first step toward astronauts being encouraged to think of and conduct their own experiments in space, like Matt Damon’s character in The Martian.”