Published online 22 February 2010 | Nature | doi:10.1038/news.2010.85

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NIH may allow stem-cell lines from younger embryos

Lines derived from pre-blastocyst stage embryos could be eligible for agency funding.

Stem cell colonyThe NIH may allow more stem cell lines to be eligible for federal funding.Clay Glennon, University of Wisconsin-Madison

The US National Institutes of Health (NIH) is proposing to extend the human embryonic stem cell (human ES cell) lines eligible for federal funding to include those from earlier-stage embryos than currently allowed.

In an online notice on 19 February, the agency proposed revising its definition of fundable human ES cell lines to include lines derived from embryos "up to and including the blastocyst stage". By contrast, the current guidelines, published last summer, define human ES cells as cells derived from "the inner cell mass of blastocyst stage human embryos".

The proposed change to the rules will be out for public consultation for 30 days from 23 February, when it is formally published in the Federal Register, which publishes government notices.

Talking to Nature, Lana Skirboll, who directs the NIH's Office of Science Policy, describes the change as a "small technical revision". Because of the NIH's commitment to being transparent, she said, "If we were going to change a comma in the guidelines we might put out a Federal Register notice."

"From a scientific and ethical point of view," she adds, there's "no reason" to exclude lines derived earlier in embryonic development.

Skirboll says the issue came to the agency's attention after Advanced Cell Technology, based in Worcester, Massachusetts, recently submitted for NIH approval five lines derived from blastomeres — single cells removed from morulas (which are embryos a few days old that have not yet become blastocysts). Details of the cell lines were published in 2008 in Cell Stem Cell1.

Lining up

The company's stem-cell lines, Skirboll says, prompted the NIH to pore over its registry of already-approved lines. In the process, officials discovered that three lines also derived from pre-blastocyst embryos had already been approved from George Daley's lab at the Children's Hospital Boston. "We are going to take those lines and put them on hold," Skirboll says, so they will be unavailable for federally funded projects while NIH completes the formal revision of the guidelines.

Daley told Nature that the current definition is "too narrow" and that "ultimately, the correction will give access to more lines".

The proposed revision "may seem like a minor technical change, but is hugely important," says Robert Lanza, Advanced Cell Technology's chief scientific officer. "Human embryonic stem cells have been derived from morula-stage embryos in many, many papers."

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Susan Fisher, a stem-cell biologist at the University of California, San Francisco, says that she has submitted ten lines derived from pre-blastocyst embryos to the NIH recently and the agency had come back to her with extensive questions. "I am super happy to see them take this issue on," Fisher says. "We obviously have a lot at stake." It is "a trivial, small change of the wording," she adds, "that could have enormous scientific benefit".

Lanza says that his company finds that several of its blastomere-derived lines were more versatile and robust than many others derived from later-stage embryos. "We have generated dozens and dozens of lines and there's no question that these are the lines we want to use."

Skirboll says that the agency plans to analyze the comments as they come in from 23 February and then "move pretty quickly" to finalize an amended definition. 

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