But although some have called the new findings key discoveries that would satisfy both scientists and religious activists, many are still skeptical.
These two methods, both published in Nature magazine, reflect the burgeoning interest of U.S. researchers in developing alternative ways to create embryonic stem cell lines without having to destroy an embryo.
Current federal restrictions limit embryonic stem cell research to cell lines created before August 2001, mainly because opponents of such research claim that traditional methods of creating cell lines require the destruction of embryos. Such a process, they say, is equivalent to murder.
The method used by scientists at Advanced Cell Technology—a biotechnology company based in Worcester, Mass.—takes one cell from a developing embryo when it is at the eight cell stage and uses this cell to create a new stem cell line.
The remaining seven cells retain the ability to implant into the uterus and develop into a normal fetus.
The second method, known as alternative nuclear transfer and published by MIT researchers, creates embryonic cell lines from cells that were engineered to have a temporary defect in them, rendering them unable to implant into a uterus.
Such cells are not implantable and thus a “non-viable artifact” that is therefore acceptable to experiment on, said William B. Hurlbut, a consulting professor in the human biology program at Stanford and a member of President George W. Bush’s bioethics committee.
The MIT research was pursued expressly to find a way to create something that is not embryo, but exhibits similar characteristics, thus avoiding the moral pitfalls of past embryonic stem cell research.
Scientists within the Harvard community said that while the research is interesting, it points to a trend of focusing on finding ways to avoid moral issues in stem cell research, rather than researching clinical applications to help cure disease.
Kevin C. Eggan, assistant professor of molecular and cellular biology and member of the Harvard Stem Cell Institute, said that although the research done by MIT scientists is a “technical masterpiece,” it still does not address the moral question surrounding embryonic stem cell research.
“Hurlbut’s proposal is that by knocking down genes in the adult cell which you’re going to clone, you will create something that never has the character of the embryo,” Eggan said. “The problem is, the cells that were created still have all the characteristics of an embryo. It is true, that they are sick blastocysts—ones that will not survive, but they are still embryos.”
M. William Lensch, another affiliate of the Harvard Stem Cell Institute at Children’s Hospital, said that if one were to treat the embryo as a human being, the Advanced Cell Technology method is not ethically acceptable, either.
“This method assumes that we have a right to manipulate the embryo to begin with,” he said. “There is no obvious benefit to the embryo, in fact, there is a very significant chance for harm—these are not trivial manipulations.”
Nor are religious conservatives are completely satisfied with these results.
“Seeking alternative ways to obtain pluripotent stem cells without creating or harming embryos is certainly a good idea, but it’s not clear that either of these approaches fills the bill,” said Richard M. Doerflinger, deputy director of the secretariat for pro-life activities in the U.S. Conference of Catholic Bishops.
Given the success of existing methods of creating embryonic stem cell lines, Eggan and Lensch both said that the moral obligation towards the sick and dying far outweigh any moral obligation towards a clump of cells.
“I’m in this field because I have people close to me that have gotten some pretty terrible diseases,” said Lensch. “I have made a commitment in my life to help them—and when people say help and you say yes, the last thing you want to do is to take your time.”
—Staff writer Risheng Xu can be reached at firstname.lastname@example.org.