Dayton Daily News (OH) -
Monday, March 16, 2009
Author: Marshall Brain
HowStuffWorks.com
Think about some of the big medical breakthroughs that have changed
the human condition for the better. There is the
invention of the vaccine, which has nearly eliminated deadly
viral diseases such as smallpox, polio, measles and mumps.
There's the rise of antibiotics, which can rapidly heal all sorts
of bacterial infections. There are surgical procedures like
heart surgery and brain surgery. Even the common appendectomy
has saved millions of lives.
Those are all huge medical advancements, many of which we take for
granted. Together they have helped to double the average human
lifespan.
Stem - cellresearch promises to open up a new area of
medical advancement that could be just as important. Once we
understand and harness their full potential, stemcells will improve millions of lives.
What is a stemcell ?
Here is a simple definition: A stemcell
is a cell that has the potential to turn into
many different kinds of cells .
To understand that, think about your own body. It contains dozens
of different cell types. You have skin
cells , which are completely different from liver
cells , which are different from the
cells that create tooth enamel, which are all different
from muscle cells .
But all those different types of cells came
originally from stemcells .
You started out in your mother's womb as a single cell
— a fertilized egg.
That little spark of life divided into a tiny clump of
cells (known as embryonic stem
cells ). Then those stemcells
started dividing and differentiating into the specific
cell types that make up your body today.
How can they be therapeutic for you?
Let's look at a few examples.
The idea of a bone-marrow transplant is actually a stem
- cell therapy of sorts. Bone marrow contains
stemcells for creating new
red-and-white blood cells .
But in certain diseases, the bone marrow stops doing its job
correctly. Or bone marrow can be destroyed in the process of
treating an aggressive cancer. So the stemcells in the marrow are replaced with new
stemcells from a donor.
One classic situation where stemcells
will probably be useful is the treatment of Parkinson's disease.
Parkinson's disease is caused when a type of brain cell
, called a dopaminergic neuron, stops working.
Dopaminergic neurons produce dopamine, and without dopamine your
brain loses its ability to control your muscles. The hope is
that stemcells can be
injected into the brain, and that they can differentiate into
the proper types of cells to replace the lost
dopamine.
Another place where stemcells
might help is in the treatment of paralysis. Imagine that you
were to fall and sever your spinal cord. Depending on where the
break occurs, this accident will paralyze your legs or your arms
and legs. You would be paralyzed for life because the nerve
cells in the spinal cord will not grow back on
their own. With stemcells ,
there may be a way to coax new cells to repair
the damage.
Another area of stemcell
research is organ replacement. Since stemcells are undifferentiated, they have the
potential to turn into specific cell types.
What if you could coax stemcells
into growing a new heart or a new kidney?
One of the first successes in the new era of organ replacement came
in 2008, when scientists grew a new wind pipe for a woman using
stemcells .
They started with a piece of donated wind pipe threeinches long.
They stripped off its outer cells to create a
scaffold for new cells . Then they seeded the
scaffold with stemcells from
the woman needing treatment.
The stemcells covered the
scaffolding and created a new piece of windpipe that her body
would not reject. Surgeons inserted the replacement windpipe and
a significant problem was eliminated.
It is easy to imagine many techniques that could become possible
with stemcells .
But the research in this area is still very new.
Scientists and doctors have a long way to go before they
completely understand stemcells
and how to use them.
