October 24, 2001
Stem Cells Made From Unfertilized Eggs
By Jeff Carpenter ABCNEWS.com
Scientists have tricked cells into dividing, and that could mean new
hope for treating diseases without violating any laws or creating new
controversy.
A new technique could someday allow scientists to study stem cells
while avoiding government restrictions on research involving cells
derived from embryos.
The technique, exhibited on mouse cells, allowed scientists to create
stem cells without using embryos. Researchers, led by stem cell
biologist Jerry Hall at the Institute for Reproductive Medicine and
Genetics in Los Angeles, announced their discovery today at the annual
meeting of the
American Society for Reproductive Medicine.
Recently, there has been a great deal of controversy over the use of
embryos in science, because some believe them to be potential human
beings.
But for the advancement announced today, the egg used to generate the
stem cells was not fertilized, and was not capable of generating life.
And while it's too soon to say the technique will work for people,
"Developing an alternate source of
[stem cells] is a really good thing," said Lawrence Goldstein,
developmental scientist and vice chair of
public policy for the American Society for Cell Biology.
President Bush this summer placed restrictions on the use of cells
derived from embryos. The government will no longer fund any research
involving the use of human embryos, only the use of previously generated
stem cells is allowed. Scientists have disagreed about how many lines of
such stem cells there are.
The process Hall and colleagues used to generate the stem cells is known
as parthenogenesis — a
form of asexual reproduction common among insects. Normally, mouse and
human eggs require
fertilization for development to occur. In this case a mouse egg was
forced into dividing without the
addition of sperm.
"We used chemical stimulation to trick the egg into thinking it was
fertilized," said Hall.
The chemical treatment involved the addition of ethanol and a molecule
involved in cell division,
neither of which causes any lasting effects on the cells that are
generated.
The scientists then treated the dividing cells with "growth factors,"
which signaled them to develop into nerve cells. Scientists hope this
new type of stem cell can be harnessed for the treatment of
neurological disorders such as Parkinson's and Alzheimer's disease.
As it stands now, these dividing cells are not capable of developing
into living organisms because the cells are not derived from a
fertilized egg. So when the researchers implanted the dividing eggs back
into the female mice, the cells were not able to grow into fully
developed offspring.
"If we were able to take them to term it would be an ethical problem,"
said Hall.
Further research is necessary to determine if the cells derived from
this process are fully functional. Subsequent work may then be done to
duplicate the technique in human eggs.
"The first and most important thing is: Can we make these cells develop
into tissues that are therapeutic?" said Goldstein.
Unfortunately for men there is no way to make stem cells from sperm. If
this technology takes off, only women will be able to generate tissue
for themselves.
Copyright © 2001 Yahoo! Inc., and ABC News Internet Ventures.
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Judith Richards, London, Ontario, Canada
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