Alternative stem cell methods work in mice: studies

By Maggie Fox, Health and Science Correspondent

WASHINGTON (Reuters) – Two alternative methods for making
embryonic stem cells work in mice and might lead to a less
controversial way to grow them, researchers reported on Sunday.

But the scientists who did the work said they still seek
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 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.

A second 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,
published in the journal Nature, show they are technically
feasible.

“They demonstrate that you can isolate the equivalent
embryonic stem cells by alternative methods that may not raise
the ethical questions. I would say they also raise more
questions than answers,” Dr. George Daley of Children’s
Hospital Boston and Harvard Medical School, who was not
involved in the research, told reporters in a telephone
briefing.

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.

RIVAL ETHICS

Opponents 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 crosses party and religious lines.

Dr. Robert Lanza and colleagues at Advanced Cell Technology
tried an alternative — 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 develop normally.

It worked in mice, Lanza said. The single cell produced a
batch of embryonic stem cells and the seven-cell embryos
“developed to term without a reduction in their developmental
capacity,” he said.

About half grew to pups in mice, compared to half of the
untouched embryos implanted into mouse mothers.

For 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 said he was not sure this method would satisfy people
opposed to cloning technology, or to the use of human embryos.

“This relies on generating an embryo and destroying the
embryo to remove the stem cells. Some people in our society
believe that would be wrong,” Daley said.

Daley said he would like to learn how 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.

All the researchers said there is no guarantee the
alternative methods would work in human embryos.

“We should be very cautious not to mislead the public that
these two papers demonstrate that we no longer need to do
research on human embryos or human embryonic stem cell lines,”
said Andrew La Barbera of the American Society of Reproductive
Medicine and an obstetrician at the University of Cincinnati
medical school.

Sean Tipton, a spokesman for the Coalition for the
Advancement of Medical Research, said he thinks legislation can
pass Congress to lift the restrictions on embryonic stem cell
research.

“We anticipate that we have the votes to prevail and it
really is a question of timing,” said Tipton, whose group
lobbies in support of stem cell research.