Page URL: https://www.bionews.org.uk/page_89464

Bush's approved stem cell lines show little potential

1 November 2004
By BioNews
Appeared in BioNews 282

Two new studies suggest that at least 25 per cent of the embryonic stem cell (ES cell) lines available for use by federally-funded US researchers have 'little potential even as research tools'. This is because they are too difficult to keep alive and were initially grown using mouse 'feeder' cells, which would cause them to be rejected by patients' immune systems and diminishing their potential as a medical treatment. President Bush has restricted the use of federal funds to ES cell research conducted on cell lines created before 9 August 2001.

One study, being undertaken by researchers at the Salk Institute in La Jolla, California and the University of California San Diego, focuses on the use of mouse cells to cultivate the ES cell lines. Newer cell colonies are not derived in this way and scientists and the Food and Drug Administration (FDA) have already expressed concern that viruses contained in the animal cells could infect the human cells as well as affecting the success of transplantation into patients. While the FDA has said that with rigorous testing, the mouse cell-fed ES cells may one day gain approval for use in humans, it is the other problem causing more concern.

The rejection problem is caused by the fact that mice, like all mammals except humans, have on their surface molecules of N-glycoylneuraminic acid. Human cells have a different molecule, N-acetyl neuraminic acid. The new study shows that human ES cells grown on mouse cells 'consume' the mouse molecules, which appear on the human cell surfaces. Ordinarily, humans have antibodies against these molecules (probably from consumption of mammalian meat). But what this means is that when other human cells - in this case blood serum - were added to the ES cells in the laboratory, antibodies attacked and killed the stem cells. To the immune system, 'these human cells look like animal cells, which leads to death', said Fred Gage, one of the research team leaders. The study has been provisionally accepted for publication in a 'top-tier scientific journal', according to the Washington Post, and full details are embargoed until that time.

The second study, which is as yet unfinished, compares the characteristics of 14 of the 22 colonies approved for use by federally-funded US researchers. Team leader Carol Ware, from the University of Washington, said that at least five of those cell lines 'will never be useful for the clinic' because they are too difficult to grow. In addition, she said, the researchers found that each cell colony had its own 'quirky propensity' to turn into one type of body cell or another, suggesting many more than 22 cell lines will need to be available to investigate the full potential of ES cells.

SOURCES & REFERENCES
Approved stem cells' potential questioned
The Washington Post |  29 October 2004
At Least 25% of Stem Cell Lines Approved for Federal Funding Have Diminished Potential for Treatment, Studies Say
Kaiser Network |  29 October 2004
RELATED ARTICLES FROM THE BIONEWS ARCHIVE
23 July 2006 - by Sean Tipton 
With unprecedented bipartisan support in the US House of Representatives, the US Senate, and from the American people, the Stem Cell Research Enhancement Act passed both houses of Congress and landed on President Bush's desk this week, only to be met with the first veto of the Bush Administration. President...
20 July 2006 - by Dr Kirsty Horsey 
US President George Bush has vetoed a bill passed by Congress that would have removed restrictions on federally-funded human embryonic stem (ES) cell research in America. The bill - known as the Stem Cell Research Enhancement Act of 2005 (HR 810) - was debated alongside two other bills...
4 November 2004 - by BioNews 
Voters in the US state of California have passed Proposition 71, a bill also known as the California Stem Cell Research and Cures Initiative. Fifty-nine per cent of people voted in favour, with 41 per cent voting against the measure, which will establish California as the first state to publicly...
HAVE YOUR SAY
to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions


Syndicate this story - click here to enquire about using this story.