What Did NASA's Twin Study Find?

NASA has been following intercellular changes in the bodies of an astronaut and his Earth-faring twin. The results are in! Learn what they found, and what further research is needed, in this episode of BrainStuff. 

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of I Heart Radio. Hey,
brain Stuff, Lauren Boglebam here. Have you ever wondered exactly
what happens to the human body when it's suspended in
space for an extended period of time? Based on Hollywood
productions alone, men and women who navigate the galaxy always
seemed to be just fine when they land back on Earth.
But are astronauts so lucky in reality? NASA has made

(00:25):
it its mission to find out. In a landmark DNA
study published in April nineteen issue of the journal Science,
researchers from John Hopkins, Stanford and other institutions revealed after
a year in space, astronauts Scott Kelly experienced no major
long term differences to his epigenome compared with that of
his twin brother, current Arizona Senate candidate Mark Kelly, who

(00:47):
stayed firmly planted here on Earth. Your epigenome is all
of the chemical compounds that have attached to your DNA
and changed the way it functions, so no major differences
is hypothetically a good thing. Here's the deal with putting
your body in space. It exposes you to harmful ultra
violet rays radiation, limited food and exercise, lower gravity, disrupted

(01:08):
sleep cycles, and an unknown number of other potential hazards.
And while scientists have spent decades studying the effects of
space travel on astronauts, most of these men and women
have traveled on missions that macks out at six months.
In order to travel somewhere like say Mars, missions need
to be much longer, and scientists say it's critical to
understand the effects that these super extended missions could have

(01:31):
on the human body. Let's talk more about how your
epigenome works. Your DNA is your genome. It's the genetic
code that tells every cell in your body how to
build different proteins, which determines how those cells function. Your
epi genome is any chemical modifications to your d NA.
These modifications don't change your actual DNA sequence, but they

(01:52):
can change how your cells use the instructions that your
DNA gives them. So these tiny chemical alterations can have
a major impact on a person's health by influencing the
way their genes are expressed. They can switch genes from
on to off, and vice versa. A major advantage of
this new research is the fact that it studies identical
twins who naturally have identical genetic material. But while the

(02:14):
study subjects offer a rare and unique glimpse into the
potential for long term genetic changes in space, the researchers
are quick to admit that their tiny sample size means
more testing is essential. With only two study subjects, they
can't be sure that any changes are due to space travel.
More research with other astronauts needs to be done. The
methodology for the study involved collecting blood samples, physiological data,

(02:38):
and cognitive measurements from each Kelly twin at various points
over twenty seven month period before, during, and after Scott's
one year space mission. If you're wondering how in the
world or universe scott samples reached the scientists from space,
they were transported via rockets. In the future, scientists hope
to process and store samples on board the International Space

(02:58):
Station itself, but for the parts of this study, samples
were rocketed back to Earth and processed within forty eight hours.
Then the research team examined the Brothers genomes, looking for
epigenetic changes, specifically focusing on two types of white blood
cells and examining a process called methylation, which occurs when
chemical compounds called methyl groups are added on too d NA.

(03:20):
Generally speaking, there were just about as many epigenetic changes
in Scott as there were in his twin. The biggest
difference was observed nine months into Scott's space mission, when
just sev of his DNA was methylated compared to th
of marks DNA. The locations of methylation were different in
both men. Scott's methylation appeared near genes involved with immune
system response, which the researchers believe correlates with additional data

(03:43):
that found that Scott had increased markers associated with inflammation,
which is a potential red flag, but again bears further
study to determine whether this difference was really caused by
Scott's location in space. Oh though, one other weird thing
that definitely did happen to Scott in space. The shape
of one of his eyeballs changed. By the time he

(04:03):
got back to Earth, his retinal nerve and the folds
in the layer that surround the eye were thicker. Researchers
think this could have to do with prolonged exposure to
low gravity, another thing to watch out for in the
future for sure. Today's episode was written by Michelle Konstantinovski
and produced by Tyler Clang. Brain Stuff is a production

(04:24):
of iHeart Radio's How Stuff Works. For more in this
and lots of other stories that involved not entirely unexpected rockets,
visit our home planet, how stuff works dot com For
more podcasts. For my heart Radio, visit the iHeart Radio app,
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