The announcement last month of a long-awaited breakthrough in stem-cell research \u2014 the creation of stem-cell lines from a cloned human embryo \u2014 has revived interest in using embryonic stem cells to treat disease. But US regulations mean that many researchers will be watching those efforts from the sidelines.<\/p>\n
The US National Institutes of Health (NIH), which distributes the majority of federal funding for stem-cell research, prohibits research on cells taken from embryos created solely for research \u2014 a category that includes the six stem-cell lines developed by Shoukhrat Mitalipov, a reproductive-biology specialist at the Oregon Health and Science University in Beaverton, and his colleagues. The team used cloning techniques to combine a donor cell with an unfertilized egg whose nucleus had been removed, creating a self-regenerating stem-cell colony that is genetically matched to the cell donor.<\/p>\n
Mitalipov\u2019s cell lines are also off limits to researchers funded by the California Institute of Regenerative Medicine (CIRM), which was created in part to support stem-cell work that is restricted by the NIH. CIRM funds cannot be used for studies that pay women for their eggs or rely on cell lines produced using eggs from paid donors. That rules out Mitalipov\u2019s lines, because his team paid egg donors US$3,000\u20137,000 each, says Geoffrey Lomax, senior officer to the standards working group at CIRM, which is based in San Francisco. That amount \u201cis above and beyond any out-of-pocket costs\u201d to donors, he says.<\/p>\n
The end result, says Mitalipov, is that a dozen or so universities are struggling to negotiate \u2018material transfer agreements\u2019 to receive the new cell lines without running afoul of CIRM or the NIH. Interest in the new cell lines is high, especially since the identification of errors in images and figures in Mitalipov\u2019s research paper shortly after its publication in Cell. But regulations would require laboratories to use only dedicated, privately funded equipment to study the new cells, a condition that only a few researchers \u2014 such as George Daley, a stem-cell expert at Boston Children\u2019s Hospital in Massachusetts \u2014 will be able to meet.<\/p>\n
That concerns Daley, who calls the NIH stem-cell policy \u201ca frustrating limitation that will preclude federal dollars being used to ask many important questions\u201d about how Mitalipov\u2019s cell lines compare with induced pluripotent stem cells (iPS), which are created by reprograming adult cells to an embryonic state. \u201cMost labs will take the path of least resistance and continue working with iPS cells unless someone shows that there is a clear and compelling reason to change course,\u201d Daley says.<\/p>\n
Mitalipov also worries that his cell lines won\u2019t be sufficiently analyzed, which he says could hamper efforts to understand how epigenetic changes \u2014 modifications to chromosomes that determine how genes are expressed \u2014 affect stem cells’ ability to transform into a wide array of mature cell types. \u201cWe just don\u2019t have that much expertise at looking at all aspects of epigenetics,\u201d he says.<\/p>\n