The following excerpts are from transcript of:
National Public Radio (NPR) - Talk of the Nation/Science from June 21,
2002 .
Although Dr. Verfaillie's research is with adult stem cells, she makes a
strong statement that both embryonic and adult stem cell research should
continue. This may be useful in rebutting those who would argue against
ESC research. Her research was recently published in Nature, along with
Dr Ron McKay's paper on embryonci stem cells.
Linda
HEADLINE: Catherine Verfaillie discusses her latest research on stem
cells
IRA FLATOW, host:
" This is TALK OF THE NATION/SCIENCE FRIDAY. I'm Ira Flatow.
... But first, two papers published yesterday in
the journal Nature may give another boost to the debate over how stem
cell
research should be conducted, one paper showing the promise of the
embryonic
approach, the other saying that adult stem cells may be more flexible
than
previously thought.
Joining me now to talk about the work is Catherine Verfaillie,
director of
the Stem Cell Institute at the University of Minnesota....
FLATOW: ... What are these new stem cells?
Dr. VERFAILLIE: Well, so we found these cells in bone marrow of
humans, but
the paper that was just recently published was really on bone marrow from
mice
and rats. It's a very rare cell, so we think it's only one in a million,
so
there's not very many of them. And if we take these cells out of the
bone
marrow and culture them in the laboratory, they appear to have the
potential to
differentiate into many, many different cell types in the culture
itself....
FLATOW: Are these cells better than embryonic stem cells?
Dr. VERFAILLIE: I think it's way too early to say that they would be
better
or even equally potent. So what we've been able to show is if we place
these
into this blastocyst they appear to behave the same way. In culture
dishes--if
you try to test what they can do in culture dishes, they appear to be
better at
doing some things than embryonic stem cells and much worse than making
some
other cell types. And the example, for instance: Embryonic stem cells
make very
easily heart muscle cells, and we have had a difficult time to do that in
a
culture dish, even though in this experiment in the blastocyst, that did
work.
Our cells appeared to make very easily cells that look like liver,
which is
the difference from embryonic stem cells, which do that a little bit less
well.
So there are definitely differences between the two...
FLATOW: ... Do you have any
idea why it would have troubled--these MAPC cells might have trouble
making one
kind of cells and not the other?
Dr. VERFAILLIE: We really don't have no good idea at this point in
time. You
know, it might be that we haven't really figured out how the culture
should be
set up to do that--that's definitely possible--or there may be inherent
differences bet--you know, there are probably inherent differences
between the
two cells, such that one of them is more coaxable in one direction than
the
other....
FLATOW: There was another very intriguing paper published also in the
journal
Nature by Dr. Ron McKay and his colleagues at NIH.
Dr. VERFAILLIE: Mm-hmm.
FLATOW: Can you talk about that a little bit?
Dr. VERFAILLIE: Yeah. So what Dr. McKay was showing is that he can
specifically direct embryonic stem cells from mice and rats to go through
the
different steps that the cells would go through in development in the
brain to
ultimately end up to become the dopamine neuron, which is important to
guide our
movements, and it's the cell that dies in patients with Parkinson's
disease. So
what he was able to show is that, with the very well-defined conditions
that he
developed, he can make the cells go through a number of steps that get
them on
the way to become dopamine neurons, and then take these cells and implant
them
back into an animal that has Parkinson's, and proved that these cells
could
completely correct the abnormal behavior, the abnormal movements of the
animal.
And so I think the importance of that study is that he was able to
show that
you can take embryonic stem cells and truly make them in a differentiated
cell
type that now can correct a defective organ in vivo in an animal
model....
Dr. VERFAILLIE: You know, his studies aren't quite ready for human
therapies.
But it's, I think, one of the first papers that provide true concepts
that these
embryonic stem cells can really be told how to behave to ultimately be
clinically useful.
FLATOW: Well, if he's proved that you can do it with embryonic stem
cells,
doesn't that throw the gauntlet down to you now to take your MAPC
cells...
Dr. VERFAILLIE: Very much so. And so what we've been able to show is
that
the cells can make cells that look like neurons and express some of these
proteins that he finds in his cells. What we haven't shown yet is that
we can
do the exact same experiment, and that's take the MAPCs and use them to
go
through these X number of steps and then put them back into the brain of
an
animal and prove that you can correct a disease. And so we haven't really
shown
all these potentially clinical applications yet, so we've only
really--you know,
we're at the beginning of, you know, where embryonic stem cells in the
mice were
many, many years ago. And so we have a cell that has characteristics
that are
similar to it, even though it's not exactly the same. And so time will
need to
tell whether MAPCs can do the same thing.
FLATOW: Mm-hmm. Are you working on experiments now along those lines?
Dr. VERFAILLIE: So we're working on experiments both in the
Parkinson's
disease model and the diabetes model, and in liver disease models...
FLATOW: Any preliminary results you can share with us?
Dr. VERFAILLIE: In vivo, we are just starting to do these studies, so
we
can't really say very much about it yet because it just takes time to
actually
prove that it will work or won't. So we're working hard to do that but,
you
know, we're just initiating the study so we really don't have any data
yet...
Dr. Verfaillie, do you think that one kind of stem cell is going to
win out
over the other, embryonic vs. adult? Or you think we equally need to
still look
at both of them?
Dr. VERFAILLIE: I'm really convinced that we need to look at both of
them.
You know, we're obviously excited about what we have, but that's--you
know, like
I said, you know, there are differences between the cells, so it's quite
possible that down the line we can't really induce one cell to all the
cell
types with a great efficiency, and the other cell is better at it. You
know, so
I think it might turn out that some cells will be useful for one type of
disease
and other cells for another disease, but I also think that, you know, we
cross-fertilize, and it's such early times for both cell types that I
think it's
way too early to say that we should give up one for the other at this
point in
time....
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