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[Brandi Dean] Good morning and welcome to the International Space Station Flight Control Room,
whereas I promised we're talking with Dr. Jean Sibonga
who is the Bone Lead for the Human Research Program.
So that's an interesting title.
[Dr. Jean Sibonga] Yeah. Essentially what that means is I am the point of contact
for every question that comes up in bone.
Whether it comes from Engineering or whether it comes
from fellow scientists or from Medical Operations.
[Brandi] Well I know we are...bones are one of the things we're really looking at a pretty hard
since that spaceflight's been shown to affect bones for the astronauts.
[Brandi] Right? [Dr. Sibonga] Yes.
In fact, probably...we've been studying it for as long as we've been having human spaceflight.
[Brandi] And...So what have we been seeing?
[Dr. Sibonga] Well over the past 10, 15 years we've been applying a clinical diagnostic test
for evaluating osteoporosis in our astronauts.
And some of that data has revealed that we have some very unique changes
in our astronauts up in space.
[Brandi] Such as? [Dr. Sibonga] Well they have a very accelerated rate of bone loss.
And the bone loss is not general across the skeleton.
It's actually a specific site.
It's the weight-bearing sites that we have here on earth.
You know so the lower half of our body versus the upper body.
It's our hips.
It's our spine.
[Brandi] Things that they don't use so much when they're not in gravity.
[Dr. Sibonga] No actually, it's the opposite.
They use it a lot in gravity so that when they go up into space there's this big differential.
There's this deficit of having to...for the bones to be strong and so they seem
to adapt more and lose more mass.
[Brandi] Okay. Well I know we see commercials about "drink more milk" and things like that.
But why is bone density important to begin with?
[Dr. Sibonga] If you were to see some of the data that kind of outlines bone loss and bone gain as humans,
you know, grow up and certainly age over time, you'll see that we have our peak bone mass
around the age of 30 and 35 and then after that it's kind downhill all the way.
You know, it's a very slow process and so when we think about osteoporosis,
when we look at the elderly people with their dowagers humps
or with these fractures from very little trauma.
This is because of the condition of bone that has deteriorated over time.
And so now it's not exactly a geriatric disease, but it's actually geriatric consequence
or a manifestation because of all of the risk factors that people are exposed to through life.
And so we want to understand if the exposure of astronauts to prolonged periods
up in space somehow contributes to osteoporosis as well.
[Brandi] And what are you findings so far?
[Dr. Sibonga] Well we're finding with this very rapid loss, that this has a concern because it seems to be
of the magnitude or the range of loss that seem s to kind of mimic
or model what we see in postmenopausal women.
Which is actually a big concern for the clinical field here.
However, we also have a lot of research data
that reveals some interesting things about these changes in space.
One is that there are actually changes in bone structure and that helps us
to understand exactly how does exercise or how do any of these are pharmacological agents
that were using as countermeasures.
Now how does this really impact the structure of bone as well as the bone mineral density?
[Brandi] Well, speaking of countermeasures, I know that's one of the big things we're looking at,
is how we actually combat that bone density loss.
So what are some of the things were doing now?
[Dr. Sibonga] Well, for one thing being up in space, there are a lot of our constraints.
We can't always give the best diet.
And we do as best as we can.
There are some issues with not having a lot of shielding.
So we don't have the ultraviolet light that helps us convert vitamin D for example.
[Brandi] I'm sorry.
Say that again.
What? [Dr. Sibonga] Ultraviolet.
Well it's the sunshine.
When we go out into sunshine it helps to convert or metabolize vitamin D
in our bodies and helps us to absorb calcium.
You know, we have all that shielding up in space on the space station.
So that has an impact as well.
And then just to be able to do exercise.
You know, we are here and in a one gravity environment here on earth
and 24/7 were exposed to that gravity.
But up there, you know, the only kind of loading that they experience on the bone is maybe
that those two hours, or less than two hours, that we have from doing exercises.
[Brandi] So what does exercise do that helps?
[Dr. Sibonga] Well, you know, we...when it keeps up the, you know...prevents kind of the muscles
from atrophy up in space, you know.
We like to maintain those muscle forces on are bone.
So essentially...excuse me...if our bones don't have to work as hard as they do here
on the Earth, because it's so easy to move in weightlessness or...you know,
they don't have that gravitational force upon us.
Then, you know, bone's pretty smart.
Well, you know, I don't need to be as strong as I usually am on Earth.
And so it's going to be very efficient, start to drop some of its mass.
And that's what we're seeing with the breakdown of bone up in space.
[Brandi] Okay. So, efficiency.
That's an interesting to put it.
I hadn't thought of it like that.
Especially when we don't use our muscles I guess in space and on Earth we'd start to lose them
and same thing happens with bones.
[Dr. Sibonga] That's it exactly.
It's a form of bone atrophy.
[Brandi] Okay. And so one of the ways we work on our bones was the exercise.
But I know there are other things y'all are doing for the countermeasures.
[Dr. Sibonga] That's right.
I mean...we want to exercise.
Kind of keep our...kind of give a reason for our bones to be strong.
But in addition, you know, that might not be enough.
Because, as I said, exercise is only about two hours a day or so, or even less than that.
And then we also want to be able to, you know, be able to provide supplementation of vitamin D
because of the issues of not having the sunlight as we do here on earth.
And then there also kind of therapeutic drugs that we use here on earth
to combat metabolic bone diseases that are very similar to the breakdown
that we see up in space in our astronauts.
So the agents that we use to prevent bone loss
in post-menopausal women are being tested up there in space.
[Brandi] Okay. So vitamin D, is that something, for instance, or the other medicines,
do all of the astronauts use them all the time or do some of them use it?
Or how does that work?
[Dr. Sibonga] Well, essentially it's a requirement so we are providing supplementation to them
and we do monitor those...that supplementation to make sure that they have, you know,
the requirements to be able to maintain that level.
[Brandi] Okay. And what are some of the results we are seeing so far?
[Dr. Sibonga] Well, you know, we don't have directly those results.
I mean...this is requirements.
So we do kind of want to monitor that all the time.
As far as the effects on the bone marrow density as a result
of the phosphonates they're very encouraging.
Also the effects of our new exercise device that's up there is very encouraging.
In fact, recently we had a bone summit of a clinical panel, advisory panel,
of some of the leaders in the bone field.
And they had a chance to review our medical and our research data.
And they also came out with that finding that it's encouraging data,
but the jury's still out on this still.
[Brandi] Okay. Well that's good news.
And what about, you know, when the astronauts get back to Earth
and they start using their bones like normal again?
Does it start to correct itself or is it that something you have to keep doing.
I don't know, on special exercises, or taking more vitamin D and other medicines.
[Dr. Sibonga] Well, you know, that's a very interesting thing that you bring
up because this is something that's dear to my heart.
Essentially, we know that there are changes in bone structure.
We know that there are changes in bone mineral density.
But now the technology that we use now, which is the clinically accepted technology,
for diagnosing osteoporosis and little old people or in post-menopausal women...uh,
is not quite, and I have some limitations when we apply it to our astronauts
because our astronauts are, you know, they're healthy and their robust
and they through a very novel change.
You know, not everybody here on Earth is exposed to a weightless environment.
And so there's actually a requirement to look at...to collect more data
as to how those changes...what those changes are in bone.
And so we have a flight study that's coming up to actually to do a monitoring, or surveillance,
of these changes in bone structure.
And from those data, which come off of the Quantitative Computed Tomography, which is an,
you know, is an x-ray based imaging device.
So when we take the data and we analyze it with this computational tool,
called Finite Element Modeling helps, it helps us to estimate the strength
of the bones particularly the hip.
And with that knowledge we know where the lows that are going to cause that bone to fracture.
We could use that to kind of direct their rehabilitation program.
You know, how successful is their countermeasure up in space,
or how successful is the rehab program after return to Earth,
so that we could possibly avoid the risk for a post-mission fracture.
Wow. Well so what about the...kind of the other side of it?
Are things that we're doing in finding out about bones with the astronauts,
is that helpful to people who are here on Earth?
[Dr. Sibonga] Yes. You know, there is a population
of folks that...who are immobilized and are at risk for fractures.
You know, like the spinal cord injury population is.
We're always looking for new ways of evaluating bone as a predictor for fractures.
And so doing the technologies that we're applying the modeling technologies, you know,
state-of-the-art, kind of, analyses.
You know, if we could apply and get those developed and validated and apply it
to our patient population, you know, this is going to be a great boon to the clinical field.
That's always good news.
Thank you so much for coming and talking with us.
We really appreciate.
[Dr. Sibonga] It was my pleasure.
[Brandi] This again was Dr. Jean Sibonga who is
with the Human Research Program, the Bone Lead for that program.
So we'll go back now to our regular ISS Update.