Stem Cell Lines Approved for Federal Funding

[Pah]

Daily Reproductive Health Report from the Kaiser Family Foundation

At Least 25% of Stem Cell Lines Approved for Federal Funding Have Diminished Potential for Treatment, Studies Say
[Oct 29, 2004]

At least 25% of the human embryonic stem cell lines approved for federal funding have "little potential even as research tools" because the lines are difficult to keep alive and were initially cultivated using mouse cells, according to two recent studies, the Washington Post reports. FDA scientists already have said that animal viruses contained in the mouse cells could infect human cells if the human embryonic stem cells grown with mouse cells are transplanted into a patient, according to the Post. However, one new study, conducted by Fred Gage of the Salk Institute and Ajit Varki of the University of California-San Diego, examined an "additional drawback" to the use of stem cells grown with mouse cells. All mammalian cells except human cells contain molecules on their surface known as N-glycoylneuraminic acid. However, most humans have antibodies to the molecule, perhaps because humans eat mammalian meat such as beef. The study demonstrated that human embryonic stem cells grown with mouse cells "consume" the mouse cells and display them on their surfaces, according to the Post. The researchers added human blood serum to the embryonic stem cells grown using mouse cells, and the antibodies in the blood attacked the stem cells and killed them. Gage said that to the immune system, the embryonic stem cells grown with mouse cells "look like animal cells ... which leads to (their) death." Gage described the study at an Oct. 12 meeting at the National Academy of Sciences, but the details of the study are embargoed until they are published in a scientific journal, according to the Post.

A second study, also presented at the NAS meeting, examined 14 of the 22 embryonic stem cell colonies approved for federal funding. Carol Ware of the University of Washington and colleagues showed that five of the colonies are so difficult to grow that they "will never be useful for the clinic," according to the Post. In addition, Ware said that each of the stem cell lines had "its own quirky propensity to turn into one kind of body cell or another, suggesting many more than the 22 colonies available will be needed if the field is to reach its full potential," according to the Post. Sean Tipton of the Coalition for the Advancement of Medical Research said that the first study "appears to point out yet another flaw with the president's policy," adding, "It means these cells are unlikely to be useful for medical purposes" (Weiss, Washington Post, 10/29). President Bush's policy limits embryonic stem cell research to the number of stem cell lines in existence on Aug. 9, 2001, when he announced the policy (Kaiser Daily Reproductive Health Report, 10/28). James Battey, head of the stem cell program at NIH, said, "No question, this raises important safety questions," but he added he could "envision techniques" by which the "problem molecules" could be removed, according to the Post. "As with so many safety issues, there are a variety of clever solutions that could potentially be brought into play that could mitigate against this kind of problem," Battey said (Washington Post, 10/29).

 

[Sunstone]

Doesn't look like Bush's compromise on the stem cell issue is working, does it?