More news on stem cells :
Stem Cells to the Rescue?
By Ellen Kuwana
Neuroscience for Kids Staff Writer
April 29, 1999
An observation about muscle
cells in brain tumors sparked research
which may one day give
researchers vital clues about how cells and
identities can be
manipulated to fight diseases.
"What do you want to be when you grow up?" A firefighter, a
doctor, an architect, a
cook, a musician? No matter what you do when you grow up, you
can always
change careers and become something else. A cell, however, once
it becomes a
heart cell or a muscle cell, cannot change. Or, so scientists
thought!
Studies in the past year have shown that some cells can change
their fate. For
example, one study showed that early brain cells called neural
stem cells can act as
bone marrow, the reddish substance inside of bones that
produces blood cells. Stem
cells are undifferentiated - like people seeking a career,
these cells do not yet have a
specific identity. Signals in the body cause stem cells to go
through the process of
differentiation to become a certain type of cell, such as a
liver cell or a skin cell.
How did researchers think of such a unique experiment?
Often in science clues to how things work come from areas
seemingly unrelated to what is being
studied. In this case, Angelo Vescovi in Italy had been reading
about brain tumors that contained
muscle cells as well as brain cells. Muscle cells in the brain?
Where did these muscle cells come
from? Vescovi decided to investigate.
Vescovi and other scientists
demonstrated that neural stem cells
could become bone marrow cells.
They used mice with bone marrow
that had been destroyed by irradiation. Irradiation
is used as a treatment for people
who have some forms of cancer such as leukemia.
The researchers injected the mice
with neural stem cells that had been marked so that
they could be identified. These
cells made themselves at home where the bone marrow
used to be and functioned as bone
marrow cells to produce new blood cells. This
process was described in the
journal Science (January 22, 1999).
Although this new information that
adult cells can change identity simply by being put in
a new environment is exciting, it
does not mean that all cells can switch identities. It is,
however, a promising result because
it gives hope for treatments for diseases where
bone marrow cells are not
functioning properly. This would include many blood
disorders and diseases such as
leukemia. This is significant because the stem cells in
bone marrow that produce blood in
your body are difficult to grow in a laboratory. If
neural stem cells can do the job of
differentiated cells and these stem cells could be
produced in the lab, neural stem
cells promise to be a feasible therapy.
The Future
Future experiments will likely investigate the possibility that
non-neural stem cells can transform
into other types of cells such as brain cells. This would be a
useful step in treating brain
disorders such as Parkinson's disease and Alzheimer's disease
where brain cells do not
function properly.
Perhaps one day it will be possible to use the neural stem
cells to make not only other cells, but
to organize these cells into an organ, such as a liver. At the
present time there are not enough
donor livers for all of the people in need of liver
transplants. If scientists could create a new
liver in the laboratory, many lives could be saved.
--
Cheers,
+----| Joao Paulo de Carvalho |------ +
| [log in to unmask] |
+--------| Salvador-Bahia-Brazil |------+
