The federally approved human embryonic stem (ES) cell lines were initially grown on mouse cells and therefore might harbor mouse-specific viruses. Ethically and scientifically, potentially exposing study participants to a mouse virus -- which people's immune systems might be unable to combat -- is not a risk worth taking in the face of safer alternatives, the panel unanimously agreed.
"Conducting a federally funded clinical trial of human ES cells, under current federal policy, would require using cell lines that none of us feel should be used in people, since it is now feasible to create safer lines," says Ruth Faden, Ph.D., M.P.H., a leader of the panel and executive director of the Phoebe R. Berman Bioethics Institute at Johns Hopkins. "So, all clinical trials -- and by extension the experiments leading to them -- should be conducted with newer cell lines not eligible for federal funding. The likelihood of getting to a clinical trial using only private funds, however, is very slim.
"Moreover," she adds, "the absence of federal funding would mean a reduced role for federal oversight of the ethics of human embryonic stem cell research."
By contrast, the Food and Drug Administration has said that growth of human ES cells on mouse cells need not be a sticking point for clinical research. Instead, they say the ES cells would then merely fall under guidelines for so-called xenotransplantation, or cross-species transplantation.
"But techniques now exist to create and maintain human embryonic stem cell
lines without using mouse cells, and such cell lines already exist, so t
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Contact: Joanna Downer
jdowner1@jhmi.edu
410-614-5105
Johns Hopkins Medical Institutions
10-Nov-2003