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Hi, Im Jeff Bulte, director of Cellular Imaging at
the Institute for Cell Engineering at Johns Hopkins.
My lab specializes in imaging stem cells,
and today I am going to use this toy box
to explain what we are doing.
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Stem cells are the cells in our body that repair tissues, for
instance the heart and the brain.
There's something unique about stem cells.
If this wiffle ball would be a stem cell, it would make
multiple copies of itself that are exactly identical.
There are two ways that stem cells can repair our tissue.
[MUSIC] One is by becoming a different
cell type, such as a heart cell or a brain cell.
And the other way is that they can excrete exosomes,
which are healing substances that look
like little bubbles that are secreted by the stem cells and
make our own cells feel better so they can repair our tissue.
[SOUND] We are starting now to
do experimental stem cell therapies, and when doctors
inject these cells, they do not know exactly where they go when
they are healing the tissue, and for how long they survive.
Sometimes, they even miss inject.
This is what a standard brain MRI looks like.
If this grey wiffle ball would be our injected stem cell, we
could not see it in the brain, because it has no contrast.
Even the best radiologists in the world
will not be able to see the gray cells on the brain MRI.
I have pioneered ways to make cells visible on MRI
by making them magnetic.
The way we do that if this gray wiffle ball again is a stem
cell, is we label them with magnetic nano particles that go
into the cell and now the cell becomes magnetic.
On the MRI when we inject these cells,
because they're magnetic they will appear black.
We can now see them, because the magnetic properties
of these nanoparticles disturbed the magnetic field of the MRI so
that there is no signal left.
Now that we can see our stem cells on MRI
what can we do with it?
One way we can use it for is to follow the stem cells in
real time during the injection and see them move.
This little car is our stem cell.
We can track the stem cells in real time very fast with MRI and
we can see now if there is a traffic jam which may be caused
by injecting too many cells or doing the injection too fast,
in which case the cells cannot enter the brain.
We can change our injection procedure by injecting less
cells, or by injecting them slower, we can follow them
now and we can see where they exactly end up in the brain,
where they park nicely and smoothly without any congestion.
One final way of imaging our stem cells is to put a in
them that will give lights if we inject certain chemicals.
So if this little finger light is our you put it in our cells.
Cells will only light up if they are alive, because only then
they will make the protein that produces the light.
We can even see if the cells divide
because they will make more lights.
The light will go off when the cells are dying, so
we know when they end up working for us and healing the tissue.
This can be a day, can be a week, or maybe a month.
So we are developing innovative ways of tracking stem cells
that will guide a therapy that is based on harnessing
the body's own power to heal ourselves.
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