All language subtitles for Science Channel Stem Cell Universe with Stephen Hawking 720p HDTV x264-TERRA

I have spent my life

exploring the mysteries
of the cosmos.

But there's another universe
that fascinates me,

the one hidden
inside our bodies...

...our own personal galaxies
of cells.

Today, we are on the brink
of a new age in medicine,

an age where we will be able

to heal our bodies
of any illness,

all because of cell inside us...

...which have special powers.

They are called stem cells.

These microscopic
miracle workers

are, however, barely understood.

Implanting them into our bodies
could unleash biological mayhem.

Are stem cells magic bullets
or ticking time bombs?

Subtitles by MemoryOnSmells
http://UKsubtitles.ru.

I haven't lived
a very normal life.

Since my 20s, I haven't had
to deal with the distractions

that come
from being able-bodied.

I have led a life of the mind.

Stem cells may give you
that same freedom...

...allowing you
to pursue your wildest dreams

without ever having to worry

about the limitations
of your body.

Dr. Robert Lanza
is one of the pioneers

of stem cell therapies.

He is already using them

to help patients regenerate
damaged body parts.

Right now,
we're in clinical trials

to try to treat blindness
using retinal cells

that were generated
from stem cells.

We've also been able to create
entire tubes of red blood cells

that transport oxygen just like
normal, transfusable blood.

Robert's work developed

from studying
how stem cells create

not just body parts,
but entire bodies.

They do this for all of us
when we start out

as nothing more
than a fertilized egg

floating in the womb.

So, imagine I'm floating
down the fallopian tube.

And first, there's one of me,
and then there's two of me.

Then there's gonna be four of me
and eight of me.

And we continue on dividing.

And eventually,
when I get downstream,

I'll be a ball
of about 100 cells.

These embryonic
stem cells are blank cells.

They have not yet become
a specific type of tissue.

But soon,
they start transforming

into specialized bone cells,
muscle cells,

and nerve cells.

Nine months later,

they form a complete person.

Once we are born, however,

these blank embryonic stem cells
disappear.

We lose the power
that they alone possess

to regenerate all of the tissues
in our bodies.

Robert is working
on restoring that power.

So, when you think
of a regular cell,

whether it's a skin cell,
a heart cell, or a blood cell,

it turns out
that that cell carries out

a very specific function.

And it carries out that function
for its entire life.

So, the question is,
what tells that cell what to do?

And that's where DNA comes in.

The way DNA is packed
into the nucleus of each cell

determines what function
it's going to have.

DNA's long double helix

is wound around a huge number
of tiny, molecular balls

in a structure called chromatin.

As we grow in the womb,
certain proteins interact

with the chromatin
of a blank embryonic cell

causing parts of its DNA
to become unspooled.

The parts that are unspooled determine
the type of cell this is going to be.

A heart cell will have
one DNA arrangement.

A skin cell, another.

This process
of cell specialization

appeared to be irreversible...

Until a breakthrough experiment
in 1962.

What scientists did
is they actually took

an adult cell in the case
of a frog, an intestinal cell,

and they put it
into an empty egg.

And what had happened
is that that egg

actually acted
like a little time machine

and brought the DNA
back in time to a point

where it could actually generate
an entire tadpole

and then, eventually,
an entire frog.

Biologists now believe
key proteins in the egg

undo all the specialized DNA
arrangements in the adult cell.

They return it
to its original state...

A blank embryonic cell

awaiting instructions
on what to become.

So, we learned
from this research

that we could actually generate
embryonic stem cells

that would grow forever,
that were essentially immortal,

and that could be turned into virtually
all the cell types in the body.

Robert has spent
the past two decades

developing techniques that
instruct embryonic stem cells

to turn into specific tissues.

I think we have the capacity to
do all sorts of amazing things

that science never
had the ability to do before.

Stem cells are likely

to revolutionize medicine
in the next several decades.

But harvesting material
from human embryos

is highly controversial.

Some see it as damaging
one potential life

to help another.

There is, however, another way

to harness
the immense power of stem cells.

Kristin Baldwin
is one of a group

of stem cell researchers

who hopes to make harvesting
eggs or embryos obsolete.

All she uses
is a patient's skin cell.

So, the old way that we used
to make personalized stem cells

was to take the skin cell

and take the DNA
out of its nucleus,

picking it up
and carrying it over into an egg

which doesn't have any DNA,

and the egg can change the DNA

and turn it into a stem cell
that has your genome.

But now there's a new way,
and all that it takes

is for us to put
these four genes

into the nucleus of
the skin cell and then wait.

And what these genes do
is reorganize the DNA

so that it starts
to look like stem cell DNA.

And once that happens,
it changes the cell around

and the cell starts to shrink

and not look like
a skin cell anymore

and loses its outside.

And over the course of a week,

it starts to look like
an embryonic stem cell.

And the only difference now between
this and an embryonic stem cell

is that it has your DNA in it.

The four genes
inserted into the cell

create four proteins that exist
naturally in an egg.

Those proteins appear to trigger
skin cell DNA

to arrange itself
just the way it is

in an embryonic stem cell.

Kristin was not the first
to create these cells,

which scientists call
induced pluripotent stem cells,

or IPS cells.

But Kristin
was the first to explore

whether these manufactured
stem cells

are really the same
as the natural versions.

So, an ideal IPS cell
or embryonic stem cell

should be able to make

all the cell types that you want
equally well

and at the same time,
not make unwanted cell types...

In particular, cancer.

But some of the cells

actually fail to make
cell types that you'd like

and others
can actually cause cancer,

and this is a worry.

So, what we are working on
is to try to find a way

to either improve
the way we make the cells

so that they're all
the first kind, the good kind,

or to find a way to test
for the differences

and identify
the ones that will be bad.

Kristin and her research team
took some skin cells from a mouse

and turned them
into a colony of IPS cells.

From them,
they grew thousands of colonies

of different adult tissue types.

Eventually, after months
of exhaustive screening,

Kristin identified
a colony of IPS cells

that never turned cancerous

and seemed to be moldable
into any cell type.

So, now that we've made
the IPS cells,

we'd like to make them into
specific cell types in a dish,

especially those which
are useful for us in medicine.

One type of cell that we can't
get from people is a heart cell,

so we can see if we could

turn the IPS cells
into heart cells in a dish.

So, in fact, when we do this,
we can make heart cells.

So that's great.

Another type of cell
we'd like to make

are brain cells, neurons,

because we can't get those
from people.

And so, we ask the IPS cells,

"can you make neurons
in a dish?"

And, in fact, they can.

But Kristin wasn't content with
making a few key cell types.

She wanted to put her IPS cells
to the ultimate test.

What we wanted to do

is take the IPS cells

and try to make
a whole organism out of those.

And so, to do that,
we wanted to make a mouse.

What we did is we took
the IPS cells

and we then put them
into a pregnant female,

and we waited.

And when the mouse
had its babies,

much to our surprise,
we found live mice

that we could later prove
came only from the IPS cells.

So now, this mouse is a clone

of the original mouse
that we took the skin cell from.

And it's a way of showing

that the IPS cells
should be able to work as well

to make all the kinds
of cells that we want

as the embryonic stem cells can.

Kristin's work has shown

that it is possible to
manufacture embryonic stem cells

without taking them
from an embryo.

But the technique is still
very new and not without danger.

As exciting
as this technology is,

we know that there is a risk.

So it may not be time

to put IPS cells
into your own body.

Rather,
we are taking the human cells

and testing them in a dish
using as many assays as we can

and ask which tests most predict

the usefulness or danger
of a cell.

Before the stem cell
revolution can begin,

we need a safe
and uncontroversial source

of embryonic cells.

One lone scientist
has a radical idea

about where to find them

in a place nobody thought
was possible...

inside our fully grown bodies.

300 years ago,
my predecessor Isaac Newton

was inspired by an apple tree

to formulate
the theory of gravity.

Newton is long gone,
but his apple tree survives.

This tree grew from the cutting
of the original.

Stem cells in that cutting

were able to regenerate
a completely new life form.

They have the same power as
the cells in a human embryo,

a power we lose
when we are born.

But one researcher believes

that if an ancient tree
can do it, so can we.

His name is Marco Seandel

of New York's
weill Cornell Medical Center.

He's scouring the human body

for a natural alternative
to manmade embryonic stem cells.

The ideal scenario would be

is if we could take
an adult cell

where you really didn't
have to do very much to it

to get that cell to convert

into a state where it resembled
an embryonic stem cell.

You could think
of Marco like a talent scout,

searching Broadway
for a uniquely versatile actor.

So, we could think
of each of these Broadway shows

as a different organ
in the body.

And like an organ in the body,

each show has individual actors
that play different roles.

And those roles
are incredibly specialized.

So, we can't just take an actor

out of one role
and put him in another role

or ask a female chorus leader
to play king lear, for example.

So it's the same in the body.

We can't take blood cells

and expect them to make
brain cells.

And we can't take muscle cells

and expect them to make
reproductive cells.

Marco's desire

to find naturally occurring,
multi-talented adult stem cells

has left him peering
deep into the human body.

Somewhere inside it,
he believes,

there is a type of super cell

that's very similar
to an embryonic stem cell.

It may be
that there's a small population

of incredibly versatile,
highly flexible cells

that, under the right conditions,
could make any of these cell types.

Marco's hunch was
to look for these super cells

in the reproductive organs.

It makes a lot of sense

that the cells that would
normally make eggs or sperm

would have more plasticity
than other adult cell types.

But there's a big snag
in Marco's plan.

You can't tell
which cells are special

just by looking at them.

Almost all cells look
exactly alike.

It's a little bit like being
here in the heart of Broadway.

Some of these actors

might be right for the part
and some not.

And it's not so easy to
figure out who's the right one.

Let's see what you got.

Can you break dance?

Alas, poor yorick.

I knew you when you were alive.

Can you do a backspin?

Oh.

Keep your day jobs.

After many months

of scrutinizing
plates and plates of cells,

suddenly,
one batch seemed to show Marco

some unusual talent.

And at one moment,
I had that sort of Eureka moment

where I came back
and looked in the dish

and realized that these cells,
all of a sudden,

were looking very different.

And the way that I knew
that this was really happening

was because we got cells
that looked like heart tissue,

meaning the cells were actually
contracting in the dish.

And sperm cells don't do that.

So we knew that these cells
had gone through

some sort of precursor stage,
reprogrammed,

and then started producing
heart cells.

It was like finding
a truly versatile actor

in a crowd of one-trick ponies.

All the world is a stage,

and all the men and women
merely players.

Love you like a bad cigar, baby.

Expelliarmus!

You got the part.

After auditioning
many thousands of candidates,

Marco and his team
discovered a cell

that was able to play any role,

a super cell
much like an embryonic cell,

but one that survives
in our bodies into adulthood.

This experience
was one of those moments

that you live for as a scientist
because you don't really know

what you're looking for
in advance,

and there are not
too many moments in science

that are that clear
and that definitive.

Marco's work could provide

a huge boost
to stem cell research.

No more need
to harvest cells from embryos

and no more need to genetically
engineer manmade versions.

I would predict that things are
gonna change incredibly fast.

It's reasonable now
to tell people,

"well, even if we don't have
the treatment for you right now,

we may have that treatment
very soon."

This could be the shape
of those treatments,

a recycled organ
stripped of its native cells,

seeded with your stem cells,
and brought back to life.

There are trillions
of cells in the human body,

all of them arranged
in a very particular way.

It seems impossible
that we could ever learn

how to construct a human being,
cell by cell.

But stem cells already know
how to do that.

Now we are beginning to capture

and control
their creative force.

It's a whole new world.

When I was a little kid,

there was a TV show called
"The Bionic Woman."

It's not mechanical,
but we're almost there.

Doris Taylor is building a heart

from stem cells.

Her process begins
with a donated organ...

Which she then turns
into a ghostly corpse.

What we're looking at here
are rat hearts

going through
the decellularization process.

And you can see here
we have a heart

that's still red and muscular.

You can see one here

that's part way through
the process.

And then here,
you can see a heart

that's lost all of its muscle.

If we sliced the heart in half,
the valves would be there,

the blood Vessels
would be there,

all the rough inside lining
of the heart would be there,

but without cells.

Doris' goal

is to transform
heart transplants.

She wants to seed
a ghost heart from a donor

with a recipient's stem cells
and then restore it to life.

If we can use

your stem cells
to build you an organ,

then you're not trading
one disease for another

like you do today.

Today, you may get a heart,

but you have to take
anti-rejection drugs

for the rest of your life.

We'd love to be able to build
an organ that matches you,

is available for you.

And that wasn't even fathomable
10 years ago, 15 years ago.

But rebuilding in a dish

what it takes our bodies

nine months to create
in the womb

is an enormous challenge.

To build a heart,
you've got to bring together

the extracellular matrix,
or ghost heart,

different kinds of stem cells,
and a beat.

So, we have this flash mob and it
looked like it came out of nowhere,

but as you can see,
there were actually cues.

The extracellular matrix
Scaffold...

The people in white coats...

who are showing the cells
where to go.

The different kinds of cells...

You see blue, green,
orange, yellow...

They're organized

like they would be in the heart,
and they're beating.

Doris and her team
have to coax stem cells

to turn into all the different
cell types that exist in a heart

and get them to precisely
where they need to go.

They're distributed differently

all throughout the heart.

What's in the valve is different

than what's
in the left ventricle

is different than
what's in the right ventricle.

The ghost heart
turns out to play

an unexpected and vital role

in this complex
cell choreography.

Doris discovered its pale flesh
is laced with chemical clues.

Its different anatomical areas,
like valves or ventricles,

are tagged
with different proteins.

These proteins trigger

the reorganization of DNA
in the patient's stem cells

and turn them into the right
heart cell type for each area.

And we can begin
to put cells back in

and the cells not only seem
to know where to go,

they seem to know
how to organize.

And they can start distributing
in ways that say,

"hey, I'm a heart muscle cell,"

"hey, I'm a blood Vessel cell."

Then we hook up a pacemaker,

and we teach them
to beat together.

And over time, they develop
contraction like a normal heart.

Now, we're not there yet,

but we've made
significant progress

and gotten to the point

that we can get to about 25%

of a normal heart contraction.

In just a few years,

custom-made
replacement body parts

built from a patient's own
stem cells will be a reality.

But these two men want

to push stem cell technology
even further.

If they succeed,

it would be
a profound achievement,

one that would mean
a great deal to me personally.

Can stem cells cure paralysis?

Our bodies
rebuild themselves every day.

We create
millions of new skin cells.

We regenerate our muscle fibers.

Slowly,
we are beginning to understand

these natural repair mechanisms
and to manipulate them.

But some parts of the body

don't seem to have
any ability to repair.

The nerves in my spine
have been slowly degrading

since I was in my 20s.

No one has yet found a way
to regenerate them.

But Paul Liu
and Mark Tuszynski believe

stem cells
will help them succeed

where all others have failed.

Mark, I found one.

Oh, let's see.

Okay.

All right.
Let's give it a go.

Okay. Let's go.

16 years ago,
I had a terrible car accident.

It broke my spine,

and I was desperate looking
for medical research

to cure the spinal cord injury.

And that's how I found
Dr. Mark Tuszynski.

I write him a letter to request

if I can work in his lab.

So, we met, and I was
really struck by his dignity,

his intelligence, his potential.

And so, Paul joined the team.

Reconnecting
a severed spinal cord

is like rebuilding
the electrical system

of a wrecked car...

Only a million times
more complex.

So, this is our cut spinal cord.

And see, we have
about 30 cut wires here.

But in reality, the spinal cord
has about a million.

We have to connect
each one of those

from the right spot
where we've done the cut

to the right target
a long distance away.

Fixing a car's electrical
harness is straightforward.

Solder the cut wires
back together,

and the electricity
will move along them again.

But in a severed spinal cord,

every nerve below the cut
has to be regrown from scratch.

In the real spinal cord,

you have to do this
a million times

from one right one going
to the other right one.

But all these wires go away.

You have to put in cells here
that will grow new wires

and link them up
to the right targets.

This is an enormously
challenging task.

Paul thought injecting
stem cells into the injury site

could automate
this intricate rewiring process.

But Mark was skeptical.

And I said,
"hmm, you know, Paul,

"people have been
working on that for 100 years

and, you know,
it just hasn't gone very far."

And so, Paul basically went off
and did some experiments

and brought back some results,

and they were absolutely
astonishing.

The cells that Paul
had implanted, few survived.

But the few that did
sent their wires, their axons,

for remarkable distances
through the spinal cord.

And this was, in a sense,

the holy grail
of spinal cord injury research

to be able to grow axons
for long distances.

But both Mark and Paul knew

that getting stem cells
to change into nerve cells

and then grow long axons
was only half the battle.

For a spinal cord especially,
for severe spinal cord,

it's a big lesion cavity.

The key step then,
at that point,

was to fill the injury site...

not have a few cells survive
at the edges of the injury,

but to fill the lesion sites

so that more cells survive
and can send out more axons.

Paul and Mark decided
to use a protein called fibrin,

which forms a mesh
over the injured area.

They hoped it would create
a foothold

for the stem cells
to latch on to.

Then this amazing phenomenon
happened.

Almost all our graphed
stem cells survived.

I took a look
into the microscope.

I backed away my chair.

I turned to him and I said,
"congratulations.

I have never seen anything
like this."

The injury site was full.

It was glowing green
with surviving cells

that completely filled
the injury.

And yet, more astonishing,

there were now
tens of thousands of axons

streaming out of the injury site
for very long distances.

And this in the most severe type

of animal-model
spinal cord injury.

This is the proof
that Paul and Mark's work

is actually healing
spinal cord injuries.

This rat was once paralyzed
in its front right leg.

Now it can pick up food with it.

This rat was paralyzed
in one of its hind legs.

Now it can walk across the
obstacle course of this cage.

It's not complete recovery,

but that is a huge amount
of recovery

after an injury
as severe as that.

This is just the beginning.
It show a potential.

We still face
a lot of challenges,

like can this wire connect
to the right target?

We have good hope.

Mark and Paul have shown

that the biological fortress
of the spine can be conquered,

that stem calls can grow
any tissue anywhere.

But not everything
that grows inside us is good.

Cancer is our greatest
medical foe.

Some fear
stem cells with cause cancer.

But others believe they are
our best hope to defeat it.

There's nothing better
in this world for me

than spending a summer afternoon
in an English garden.

Here, nature Springs forth
a myriad of growth.

But not everything in a garden
is a gardener's friend.

We have weeds
inside our bodies, too.

We call them cancer.

Just like any other tissue,
cancer grows from stem cells.

If we can learn
how to destroy them,

we could wipe out cancer
at its root.

U.C. Davis Professor
Paul knoepfler

is leading the attack
on cancer stem cells.

He sees them
as the great enemy within,

floating around inside us,
waiting to unleash havoc.

We've come to learn
in the last few decades

that cancers have
two main types of cells.

There's sort of a generic
cancer cell,

and then there's these
stem cells within the cancer

that we call
the cancer stem cells.

Paul thinks our
current attempts to beat cancer

are a bit like
his daughter Melanie

playing a game of Marco polo.

In our analogy
of the cells in the pool,

we have the general cells
of the tumor, the red cells.

They're not very harmful.

But the yellow cells, those rare
ones, are the cancer stem cells.

And they're the ones
we really need to worry about

because they can grow
an entire new tumor.

The yellow stem cells
are responsible

for all of
the cancer's growth...

Good job, Mel.

...just as
Paul's daughter struggles

to grab hold of a yellow ball
because she can't see

that her friends
are moving them.

Keep going.

Get all those balls
out of the pool.

So, researchers
have been struggling

to zero in on the really
dangerous cells in a tumor.

Hey.

All right, Melanie.
Time's up.

You can take your blindfold off.

Look.

You got all the red balls
out of the pool,

but we didn't tell you
that your friends here

had all those yellow balls,
which are the cancer stem cells.

And it's important to find those
to help cure the cancer.

Paul's search
for these killer cells

is not driven
by scientific interest alone.

He is also a cancer survivor.

So, I've been studying cancer
for a really long time.

And then one day, I found out
that I, myself, had cancer.

And so, that was
a very scary experience.

When you are a researcher,
it's kind of impersonal.

You're studying cells
and test tubes.

And then all of a sudden
when you have cancer,

it's a totally different
experience.

Paul had surgery
to remove his tumor

and is in remission.

But he may still have
cancer stem cells in his body.

One day, they could spring
back into action.

Surgery only gets
part of the tumor in most cases.

And so I have to face the fact
that there could be

residual cells
floating around in my body,

and some of those
might be cancer stem cells.

And those could cause
the cancer to come back

in a few years or in a decade.

Like Melanie's friends

sneaking away from her
as she reaches blindly for them,

cancer stem cells can slip past
chemotherapy,

radiation, and surgery.

The cancer stem cells
are more migratory

that just the average cell
in the cancer.

And so that means
that they can kind of

jump ship from the tumor, float
around in your bloodstream,

and lodge somewhere else
in your body

and just kind of wait there
like a sleeper cell

to potentially cause a tumor
later on.

Paul is perfecting a way

to detect these deadly cells.

He has found
that some of the same proteins

that trigger DNA reorganization
in embryonic stem cells

are also active
in cancer stem cells.

All cells really have
proteins on their surfaces

that are kind of like
identity codes.

And what we're hoping is that
cancer stem cells will express

a slightly different pattern
than other cells in the tumor.

And so, that pattern
might be like a signature

for us to hone in on to identify
the cancer stem cells

and then essentially zap them
and kill them.

And what we're hoping is that will
lead to fewer recurrences in patients.

Killing cancer stem cells

may finally bring us victory

in the long war
on this dreaded disease.

But stem cell research
could deliver

an even greater prize
for all of us...

a genuine
medical fountain of youth.

I relish the rare
opportunity I've been given

to live the life of the mind.

But I know I need my body

and that it will not
last forever.

As we age
and we make copies of cells,

tiny errors
creep into our genes.

This process seems inevitable,

but stem cell researchers
disagree.

One of them
is Dr. Vincent Giampapa.

He believes our body's own
natural reserves of stem cells

can stem the tide of decay.

The origin of the aging process

really starts in our stem cells

because that is a reservoir
of the regenerative power

and the ability to have
our body cells renewed

and repaired as we age.

The stem cells we have
in our adult bodies

are not all-powerful
like embryonic stem cells.

They are specialized
to replenish

specific tissues we need
to maintain ourselves

like blood, bone,
skin, and muscle.

As we age, however,

this repair system
begins to break down.

What we've learned recently is
there is a clock, if you will,

inside the cells
that actually changes

or, if you will,
ticks as each year goes by.

And as that happens, certain genes get
turned off and other genes get turned on.

Our DNA is not frozen
over our lifetime.

Our environment
and the choices we make

influence and change
our genetic profile.

So, if we live
in a healthy environment,

that genetic clock is slower.

If we live in an unhealthy or stressful
environment, the genetic clock accelerates.

We can think of the DNA

inside one of our body's
stem cells like a newspaper.

So, this morning, I picked up
this newspaper in my driveway,

and I have a nice,
clean newspaper.

But I might drop that newspaper
in the street

and it might wrinkle
or get dirty.

As the day goes on,

I might spill
some coffee on this newspaper.

It might even rain
this afternoon.

The key thing here is,

I'm not gonna be able to get
another copy of this newspaper.

But as we age, what happens
to those young cells

is the letters on that DNA

start to get damaged
from normal aging,

from the environment.

And that newspaper
or, if you will, that cell

becomes less efficient.

We really can't read
the information.

And that cell, then,

can't make
accurate copies of itself,

which then rapidly accelerates
the aging process.

But Vincent believes

this aging process
can be reversed.

His research team
at the cell health institute

claims it has already begun
rolling back the cellular clock

on our body's natural supply
of stem cells.

What we're really doing

is using the proteins
from younger cells

from another person

to reprogram older cells
from a different person.

What we've seen already
in our early studies

is that those senescent genes

that produce
inflammatory compounds

and things that are directly related
to cancer have actually been reversed.

They've been turned off.

So, that's been a very good sign

that most likely,
in the long run,

this will certainly be a safe
therapy in the next few years.

In the future,
Vincent Giampapa believes

we'll all be able to protect
ourselves against cell aging

as long as we have the foresight
to plan ahead.

Well, one of the most recent
approaches

to controlling the cellular aging
clock and the quality of those cells

is to store those stem cells
at a young age,

say between 21 and 35.

In essence, freezing
an essential part of ourselves,

put it in storage,
if you will, in the bank,

and be able to use that
later on in life

when, for instance, we might
have a problem with our heart

or our liver or our lungs.

In essence,
what we're looking to do

is somehow we have to make
copies of this newspaper

or make copies of ourselves,
put them in storage,

and be able
to go back to that storage

when we need them
for whatever purpose.

This is not skin-deep cosmetics.

It's true biological youth

driven by the incredible
regenerative power

we all have inside us...

The power of stem cells.

Our whole focus is attempting to
improve the quality of life we have,

decreasing the illnesses
we all suffer as we get older

so we can enjoy the time we have
with our families and friends

and really be more productive
as we age.

Just as we looked at the sky

to understand
our place in the universe,

stem cell scientists are looking
deep inside our bodies

to figure out how we can take
a step forward as a species.

Within the next few decades,
I am sure

they will have developed
treatments

that can extend human life
by years.

But also, I have to accept

that my life has
probably come too soon

to witness
the golden age of stem cells.

And so, to those of you
who will enter this age,

I have these words of caution.

When physicists cracked open
the world of the atom

almost a century ago,

they unearthed
a new frontier of knowledge,

one that came with
remarkable power...

And grave risk.

As we strive to master
stem cell technology,

we are gaining profound insights into
the forces of nature that create...

Sustain...

And destroy life.

A brave, new world lies
ahead of us.

I believe we will use
this knowledge

for the good of us all,

and I hope you will
prove me right.