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>> Kelly Humphries: Hi, and welcome to Mission Control
where we have Scott Smith, a doctor that's with us to talk
about the effect of microgravity on humans when they're in space
and not only how it affects them while they're in space
but also how it affects them
when they come back home to earth.
Welcome in, Scott.
>> Dr. Scott Smith: Thank you.
It's good to be here.
>> Kelly Humphries: So, you are the principal investigator
for a couple of different experiments onboard the
Space Station.
One that's called Pro-K
and another one that's called Nutrition.
You recently published a paper about vision changes
in astronauts in space.
Can you take a minute and discuss the two experiments
that you're the principal investigator on
and any others you're working on for that matter
and give us an overview of those.
>> Dr. Scott Smith: Okay.
Will do. Well, the two experiments as you mentioned one
of them is called Pro-K and that's one where we're looking
to use diet as a way to mitigate the bone changes
that we see during space flight.
We're trying to modify the diet to lessen the bone loss
that astronauts have during flight.
What we do is it's called Pro-K because what we're looking
at is the ratio of animal protein to potassium,
which is abbreviated K in the diet.
What we believe is that by lowering the amount
of animal protein or red meat if you will in the diet
or increasing the amount of potassium in your diet mainly
in fruits and vegetables that that ratio can affect bone.
So what we're doing is we have crews consume a controlled diet
for 4 days where they eat a menu that's either high
in that animal protein to potassium ratio or low
and at the end of that we collect blood and urine
to look at bone metabolism.
This is an exciting week for us
because Joe [inaudible] is doing his first session for us
so he's consuming that menu these days right now
and on Friday morning we'll collect his first blood
and urine samples onboard station.
>> Kelly Humphries: That's great.
So that's the Pro-K.
What about Nutrition?
>> Dr. Scott Smith:
The Nutrition experiment has been going
on a little bit longer.
It in some ways looks the same
and what we're doing is collecting blood
and urine samples from the crew over the course
of a six-month mission to look at nutritional changes
and other biochemical changes
that we can see in blood and urine.
One of the striking things and you mentioned the paper
that we just recently published is when we realized
that there were astronauts that were coming back from space
with vision changes, we started to look at our data to see
if there's anything in our data that would help explain
or help understand why some crew members had vision issues
and some crew members did not.
When we started looking at the data,
what we quickly found was what we would call differences
between folks that had vision changes and folks that did not
in parameters in what we call the one-carbon metabolism
pathway, which is a mouthful.
What this is, the way I like to think of this is if you think
of the human body as a factory
that within the body there are a number of assembly lines
that do different things.
They either make things, they move things,
sometimes they break down things.
The one carbon metabolism pathway is one
of those assembly lines.
On an assembly line, the way I like to think about this is
that if you're working on an assembly line
and you have two conveyor belts bringing you parts
and your job is to put those two parts together if one
of those conveyor belts slows down,
the other conveyor belt will start to back up;
that is you'll have extra of those parts.
That is what happens in the body that if one pathway slows
down some of the things in that pathway will build up.
What we found when we started looking at the blood
of astronauts that have vision issues is we found elevations
in four of the compounds in this specific pathway and what
that led us to believe is that, well, first led us to think
that there was something going
on with one-carbon metabolism pathway.
The next thing you do the reason we were looking at this pathway
to begin with is that it's very nutrition rich.
There's at least four vitamins that are involved
in this pathway, Vitamin B-6, Vitamin B-12, folate, biotin,
and the first thing you need to do is rule out deficiency
of those vitamins because if you're deficit in folate,
for example, these pathways will be altered as well.
So, that was our first concern and we went
in long story short we verified that.
We did not have, we did not have any crew members
who were deficient in any of those vitamins.
So, what we then started doing was looking at this pathway
and trying to understand it better ourselves and we came
to the realization that what happens oftentimes is
that there are enzymes in these pathways that help to work.
So the enzyme in this case is the person putting those two
things together on the assembly line.
What we realized is that there are differences
in different groups of the population in these enzymes.
The differences exist in large percentages of the population.
So, for instance, one specific enzyme we looked
at about half the population has one form
and about a third has another form
and about 15-20% has the third form.
>> Kelly Humphries: And when you're talking
about the population, you're talking
about the entire human race.
>> Dr. Scott Smith: The entire human population; that's right.
So what we're talking about is roughly 15
out of every 100 humans has this particular enzyme
that causes this pathway to work slower and so we're not talking
about random occurrences or one in a million type things.
This is a lot of people.
When we started looking, again, when we found these differences
in the astronauts, in the astronauts
that had vision issues, specifically what we found is
that not only were there differences in those
that had vision issues and those
that did not we found those differences before flight.
So, we realized this likely had nothing to do
with the space flight itself but that this may have been related
to something that was different
about those individuals before they even flew.
So this was obviously a very exciting find
and what we're now trying to do is we're going back
and doing a follow on study that will allow us to go in and look
at those specific enzymes to see which type
of enzymes these individuals have to see if this is right
because there is the possibility that this is still a fluke;
that we found a difference but that it has nothing to do
with the actual vision changes.
So, we wrote a proposal, we got approved
to go do this follow-up study
and earlier this month we actually started recruiting
subjects to participate in that where we're actually going back
to the astronauts and talk to them about the experiment
and asking them if they'd be willing to allow us
to collect blood to go in and look again
at the exact specific enzyme.
So, it's a very exciting point in time.
>> Kelly Humphries: And so if your hypothesis ends
up being correct as you do your follow on studies,
there's some important ramifications
for a long duration space flight aren't there?
>> Dr. Scott Smith: Well, I would say two things.
One, again, if our hypothesis is right,
there could be some significant implications
for long duration space flight and, you know,
NASA when we realized that there were vision changes
in astronauts that is it's been described
as the most significant clinical issue
of human space flight to date.
So this is something we need to fix before we go further
and there's a lot of folks working hard trying
to better understand this, trying to figure out ways
to counteract it and protect against it.
If we're right, we will help drive that pathway
to better understand how to counteract it,
to better understand what the issues are.
If we're right beyond NASA, this pathway affects, again,
15 to 20 out of every 100 people and the implications
for treatment of disease on earth or understanding
of disease on earth could be significant.
>> Kelly Humphries: Great.
So that's a really potentially big benefit
to the human population based on research that's done
on astronauts on orbit.
>> Dr. Scott Smith: Absolutely.
Absolutely.
>> Kelly Humphries: Can you tell us a little bit
about how microgravity itself makes your experiment possible?
How does that change the game?
>> Dr. Scott Smith: Well,
it depends on what you're looking at.
Going back to the Pro-K experiment where we're looking
at bone, what the space flight allows us to do
from a bone perspective is to study very healthy individuals
in a very unique environment; that is weightlessness.
What happens is the astronauts lose bone
at about 10 times the rate of a woman with osteoporosis.
So, what it allows us to do is narrow in and study people
that typically don't have other health issues
and in a much shorter amount of time allows us to study how
to counteract the bone loss of space flight,
which again the potential implications of that
for the general population are significant
and we can do studies and learn things in a matter of months
that would take 5, 6, 10 years to do
in a similar ground-based population.
>> Kelly Humphries: Okay.
It takes a while for those kinds of things to be manifested
in normal medical treatments here on earth, right?
>> Dr. Scott Smith: Absolutely.
Changes in human physiology tend to be rather slow,
which is a good thing for us, but understanding the research
that it takes to better understanding a disease process
or a physiological change to better understand the process
and figure out ways
to counteract it is indeed a slow process.
>> Kelly Humphries: Okay.
Where do you work here at the Johnson Space Center?
>> Dr. Scott Smith: I work
in what's called the nutritional biochemistry lab
with the Space Life Sciences director here in Houston.
>> Kelly Humphries: Is that the traditional kind of laboratory
that you'd expect to see
in anybody that's studying nutrition?
>> Dr. Scott Smith: In a sense, yes, it is.
It's very similar to a nutritional biochemistry lab
that you'd find at any university.
The difference is that we by the nature
of what we do we cover a much broader area
that is we're looking at not only nutritional assessment,
we're looking at dietary intake.
We're looking at vitamin status, we're looking at minerals,
we're looking at bone, we cover the gamete whereas if you were
to go to a university and go
to a lab you'll find somebody working on one enzyme
and one pathway with one vitamin
and they'll spend their career trying to understand that.
What we do to counteract that because, again, we try to cover
as much ground as we can we typically will bring
in individuals from the outside.
So we always work with scientists at universities
across the nation, around the world
to help us understand specific areas
that we may not have the direct expertise in.
>> Kelly Humphries: Okay.
And since you mentioned universities what's
your background?
Where are you from?
Where did you go to school?
>> Dr. Scott Smith: I did both my degrees at Penn State.
My undergraduate degree was in biology
and my Ph.D. was in nutrition.
>> Kelly Humphries: What's your hometown?
>> Dr. Scott Smith: Right now it's Houston.
I spend more time here than anywhere so.
>> Kelly Humphries: [laughter] Okay.
>> Dr. Scott Smith: I grew up outside of Philadelphia
and spent a lot of time at Pennsylvania,
but I've been here a little over 20 years now.
So, it's home.
>> Kelly Humphries: Okay.
Great. Well, Dr. Scott Smith, thank you so much
for being with us today.
Really interesting work that you're doing right now
and it's got some potential impact for future
of human space flight and for just folks here on the ground
with their bodies and treating disease.
>> Dr. Scott Smith: Absolutely.
Thank you for the opportunity.
It was great to be here.
>> Kelly Humphries: Great.
Thanks again.
>> Dr. Scott Smith: Thank you.