Oct 16 2005
According to researchers in the U.S. two alternative methods for making embryonic stem cells, work in mice and could lead to a less controversial way to grow them.
The scientists who did the work however say they are still seeking changes in U.S. law that would give them federal funds to work with the human cells and find ways to use them in treating diseases such as cancer and genetic conditions, and in studying others.
One team at Massachusetts-based Advanced Cell Technology, used an established fertility technique called pre-implantation genetic diagnosis to take a single cell from a mouse embryo and use it to grow a batch, or line, of embryonic stem cells.
Another team at the Whitehead Institute for Biomedical Research at the Massachusetts Institute of Technology managed to genetically damage cells and then use cloning technology to make a crippled mouse embryo that could never develop in the womb. They then developed embryonic stem cells from the embryo.
Both methods had been discussed as ways to bypass objections that some people including U.S. President George W. Bush have to embryonic stem cell research.
The studies show they are technically feasible.
According to Dr. George Daley of the Children's Hospital Boston and Harvard Medical School, who was not involved in the research, the studies demonstrate that you can isolate the equivalent embryonic stem cells by alternative methods that may not raise the ethical questions.
Stem cells, the body's master cells, are used as a source of new cells and tissues. There are several kinds, but the controversial ones are those taken from very early human embryos.
Taken a few days after fertilization, these cells have the power to produce any type of cell in the body and are considered enormously powerful if scientists can learn how to direct their development.
Opponents however say any destruction or even manipulation of a human embryo is immoral.
Currently, federal funds for experiments using human embryonic stem cells are restricted, and rival bills in Congress would lift these restrictions or tighten them further.
The debate has crossed both party and religious lines.
Dr. Robert Lanza and colleagues at Advanced Cell Technology tried an alternative method, by taking a cell from an embryo when it only has eight cells, and using it as a source of stem cells. The remaining seven-cell embryo can still develop normally.
Lanza says the method worked in mice, and the single cell produced a batch of embryonic stem cells. The seven-cell embryos then developed to term without a reduction in their developmental capacity.
Apparently about half grew to pups in mice, compared to half of the untouched embryos implanted into mouse mothers.
In the second study, Rudolf Jaenisch and Alexander Meissner of the Massachusetts Institute of Technology genetically disabled a gene in a mouse cell that is important to allow a fertilized egg to become an embryo. They then cloned the cell, grew an embryo, and extracted stem cells from it.
Daley is unsure this method would satisfy people opposed to cloning technology, or to the use of human embryos as it relies on generating an embryo and destroying the embryo to remove the stem cells.
Daley would ideally like to be able to take a cell, perhaps a skin cell, directly from a patient and transform it into a batch of embryonic stem cells without ever generating an embryo. This method would allow for tailor-made medical treatments or transplants.
The researchers all agree that there is no guarantee the alternative methods would work in human embryos.
Andrew La Barbera of the American Society of Reproductive Medicine and an obstetrician at the University of Cincinnati College of Medicine, cautions against misleading the public that research on human embryos or human embryonic stem cell lines is no longer needed.
A spokesman for the Coalition for the Advancement of Medical Research, Sean Tipton, thinks legislation can pass Congress to lift the restrictions on embryonic stem cell research.
The studies are published in the journal Nature.
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