Stem Cells Made From Unfertilized Eggs

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.

Tricking Eggs

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.

The Next Step

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.

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