Stem Cell Universe with Stephen Hawking Page #2

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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

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