Human Embryonic Stem Cells: Where Are They?

[Murray Charters <mcharters@xxxxxxxxxxxxxx>]

Human Embryonic Stem Cells: Where Are They?
By Nancy Touchette
Posted: October 30, 2003

When President Bush enunciated his policy for research on human embryonic stem 
cells in 2001, many researchers felt
duped. Citing the existence of ?more than 60 genetically diverse stem cell 
lines,? he announced that federal funds
could be used for research only on stem cell lines created before August 9, 
2001, the date of his announcement.

Since the President's edict, stem cell researchers have disputed the number and 
quality of cell lines said to be
available.

?The day after the President's speech, our phones were ringing off the hook,? 
says Kevin Wilson, a spokesperson for the
American Society for Cell Biology in Rockville, Maryland. ?We kept getting 
calls from scientists saying they were only
aware of 10 available cell lines. Sixty sounded like a good number, but in 
reality these cells were dressed up as
something they weren't.?

Now, two years later, as a result of efforts by the US National Institutes of 
Health (NIH), researchers are getting a
clearer picture of what is and isn't available. NIH has created a Stem Cell 
Registry to document existing stem cell
lines and their availability. And a Stem Cell Characterization Unit has just 
completed its initial tests to assess the
quality of available cell lines.

A total of 78 stem cell sources have now been catalogued and approved for what 
is known as the ?Presidential List,?
which includes all the derivations?cell lines or samples of cells frozen 
away?that can be studied using federal funds

But of the 78 approved cells, only 12 are currently available for distribution. 
These cell lines, which have just been
characterized, are listed in the NIH Human Embryonic Stem Cell Registry.

?Many of the lines sanctioned by the president are not available,? says Leonard 
Zon, president of the International
Society of Stem Cell Research and a researcher at Harvard Medical School in 
Boston . ?Some of these lines have patent
issues and some were never cell lines to begin with.?

The Stem Cell Characterization Unit, under the direction of Ronald D. G. McKay 
of the National Institute of
Neurological Diseases and Stroke has characterized the 12 stem cell lines on 
the NIH Registry and has posted its
initial results on the NIH Stem Cell website.

The unit tested each cell line to learn whether it has been contaminated by 
pathogens or has any visible chromosome
abnormalities. The cells have also been examined to see whether they express 
certain markers that indicate the cells'
potential to become any type of specialized cell and for their ability to 
self-renew or replenish themselves.

The Stem Cell Characterization Unit and Stem Cell Registry are both part of the 
Stem Cell Task Force, a larger effort
at NIH to support and encourage stem cell research. The task force, headed by 
James Battey, director of the National
Institute on Deafness and Other Communication Disorders, aims to encourage the 
training of more stem cell researchers
and to make more human embryonic stem cell lines available.

NIH provided funding in 2002 to all the institutions that currently make their 
cells available. In exchange for the
funding these organizations agreed to distribute their available cell lines for 
a $5,000 fee. Researchers can now
obtain a sample of human embryonic stem cells from any one of five 
organizations listed on the registry to receive one
of the 12 available lines.

Researchers are not prohibited from studying human cells not on the list or 
from creating new cell lines but they
cannot use federal money to do so. Not surprisingly, several companies and 
academic researchers in the U.S. and abroad
have reportedly developed new embryonic stem cell lines without the use of U.S. 
funds.

For example, researchers at King's College London in the United Kingdom 
announced in August 2003 that they had created
a new human embryonic stem cell line. And at the first meeting of the 
International Society for Stem Cell Research,
held in Washington, D.C., this past June, Douglas Melton of Harvard University 
in Cambridge, Massachusetts, announced
that he had derived several potential cell lines from human embryonic stem 
cells that he is now characterizing.
Melton's work is funded by the Juvenile Diabetes Foundation.

There are several reasons why so few of the approved cells are available for 
distribution. Many of the cells approved
for funding were not cell lines at all but were frozen, uncultured cells.

To be considered an embryonic stem cell line, researchers must be able to 
maintain the cells in culture in an
undifferentiated, or unspecialized, state. The cells must be able to renew 
themselves, and they must be able to form
all three of the basic cell types found in the early developing embryo. Many of 
the cells on the Presidential list do
not satisfy these criteria and are of little use to stem cell researchers.

Many researchers had derived cells from fertilized embryos but had not tried to 
maintain them in culture. For example,
nine cell lines on the approved list that were derived by the Karolinska 
Institute in Stockholm could not be cultured.

Other cell lines are unavailable for legal and political reasons. Ten cell 
lines were developed in India but the Indian
government prohibits the export of human cells. One company in Korea has 
refused to make cells available to U.S.
government-backed researchers.

And some companies refrain from sharing their cell lines due to their 
commercial interests.

Zon says that more cell lines were included on the original list to ensure that 
they would not be excluded from federal
funding. Some of these cells had not been fully characterized and had not been 
maintained in culture, so their
usefulness is uncertain.

Zon says this was not an attempt to mislead the public, but an effort to ensure 
that all possible cells were eligible
for funding.

?There was this sense of wanting to be over-inclusive, to over-interpret what 
was really available, so we wouldn't miss
out on potentially useful cells,? he says.

NIH has recently awarded grants totaling $6.3 million to the University of 
Washington in Seattle, the University of
Michigan Medical School in Ann Arbor, and the WiCell Research Institute in 
Madison, Wisconsin, to develop the
infrastructure to scale up production of the useful stem cell lines so that 
there will be more cells available to
researchers.

NIH's actions to promote stem cell research are being received with cautious 
optimism by the stem cell research
community. In May 2003, NIH Director Elias Zerhouni testified before a 
congressional subcommittee that 11 human
embryonic stem cell lines are available to researchers and are listed on the 
Stem Cell Registry. Since that
announcement another stem cell line has been added, bringing the total to 12. 
According to Wilson, Zerhouni's testimony
went a long way in regaining the trust of scientists.

The scientific community will be forever grateful to Battey and Zerhouni,? says 
Wilson. ?They injected a dose of
reality by admitting that we are really working with far fewer cell lines than 
Bush had claimed. They are doing
everything they can to get the most science out of a bad policy.?

Reference:

NIH Human Embryonic Stem Cell Registry: available cell lines


Cells approved for U.S. Federal Funding


SOURCE: Genome News Network


* * *

----------------------------------------------------------------------
To sign-off Parkinsn send a message to: mailto:listserv@xxxxxxxxxxxxxxxxxxxx
In the body of the message put: signoff parkinsn