Why the Stem Cell Advance May Not Be a Breakthrough

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A single cell is removed from a human embryo to be used in generating embryonic stem cells for scientific research.

The news that a Massachusetts company, Advanced Cell Technology (ACT), had found a way to generate embryonic stem cells without destroying the embryo from which the cells came has already predictably raised the hopes of stem cell research supporters. But while ACT enjoyed a nearly 360% jump in its stock price after the news was reported Wednesday in the journal Nature, it's not at all clear that its achievement, while noteworthy for scientific reasons, has actually succeeded in resolving any of the ethical and moral objections — or even the legislative restrictions — to embryonic stem cell research.

In a statement, the Bush Administration, which has repeatedly objected to embryonic stem cell research because it involved what it views as the destruction of life in order to save life, noted, "Any use of human embryos for research purposes raises serious ethical concerns. This technique does not resolve all those concerns. The President is hopeful that with time scientists can find ways of deriving cells like those now derived from human embryos but without the need for using embryos."

Senator Edward Kennedy took the opportunity to highlight the achievement from his state, and criticize the President's position. "I commend Advanced Cell Technology for its remarkable breakthrough, "he said in a statement. "It's tragic that the current Republican Congress continues to rubber stamp the restrictions that deny federal funding for scientists engaged in medical research that could save or improve countless lives."

Dr. William Hurlbut, head of the President's Council on Bioethics, wondered about the moral and biological implications of removing one cell from a two or three-day old developing embryo. "To pluck one [cell] out is to take something out of the original embryo," he says.

ACT's announcement is an important feat, certainly, particularly from the scientific point of view, since it's the first time that scientists have successfully created human stem cell lines from a single cell of an eight-cell embryo (ACT did the same thing with mouse stem cells last year.) "Many people, including the President, are concerned about destroying life in order to save life," leader researcher Robert Lanza told TIME." This paper now describes a technique to generate stem cells without harming the embryo, and thus without destroying potential life. We are hoping that his solves the impasse, and removes the last rational reason to oppose this work."

But the fact remains that any stem cells created using this approach would still not qualify for federal funding — since it would entail the creation of new stem cell lines — and, in addition, still does not address concerns about harm to the embryo that many religious and conservative groups have. For members of the Catholic Church, which opposes any creation of human embryos outside of the human body, the technique still involves manipulating — and potentially harming — an embryo. "The problem is that the researchers are subjecting a human being to risks without any advantage to that individual," says Edward Furton, staff ethicist of the National Catholic Bioethics Center in Philadelphia.

And still others, who accept in vitro fertilization, aren't convinced that ACT's technique does not harm the embryo. The procedure, which is based on pre-implantation genetic diagnosis, a test commonly done when couples at IVF clinics are concerned about passing on genetic diseases such as cystic fibrosis and Duchenne muscular dystrophy, is supposed to spare the embryo after a single cell is removed. But since the test has only been used widely since the 1990s, it's not absolutely clear that taking one cell out of the embryo has no effect on normal development of the implanted embryos.

And even if the procedure turns out to be safe for the embryo, there remains the very real question of what quality stem cells the technique would produce. Some studies suggest that even at the eight-cell stage, when the blastomere, or single cell, is removed, the embryo has already embarked on a development path, and has assigned certain lineages to each of the eight cells; if that's the case, then the stem cells derived from a particular blastomere may already be restricted to becoming just specific types of cells — and may not be useful in generating any of the over 200 different tissue types in the body.

As scientists are quick to point out, this report is the first of what will likely be a series of papers replicating and confirming the technique. Until more labs try and succeed in generating stem cells this way, it's not clear what role this procedure will have in resolving the stem cell impasse — if at all.

With reporting by Mark Thompson/Washington