Altered Nuclear Transfer
Date: April 12, 2007
Time: 10:21am est

In the search for scientifically and ethically acceptable alternatives to embryo-destructive stem cell research, altered nuclear transfer (ANT) requires particularly close analysis, due both to its complexity, and to its potential as a scientifically acceptable substitute source of embryonic-like stem cells, and substitute platform for the kinds of research otherwise afforded by actual living human embryos.

ANT is the conceptual proposal advocated by Dr. William Hurlbut of Stanford University and member of the President's Council on Bioethics. In ANT, a normal adult body cell is genetically modified. In its nucleus, genes essential for normal embryo formation are drastically altered. This cell is then implanted in an egg with its nucleus removed-the same technical procedure used in cloning. Theoretically, however, the resultant product of the procedure would not be an embryo, but a disordered biological artifact, capable of yielding embryonic-like stem cells, but otherwise more akin to very unusual tumors called teratomas which can, although rarely, form spontaneously for example in female ovaries.

In October, 2005, the journal Nature reported that MIT researchers Alexander Meissner and Rudolf Jaenisch had, for the first time, used ANT in laboratory mice to derive a line of "fully competent" mouse embryonic stem cells. Their use of the procedure produced what were arguably not mouse embryos, but rather disorganized masses of cells that appeared to lack the organization necessary to be considered genuine mouse embryos. The Meissner/Jaenisch research constituted proof of principle that ANT works scientifically-at least in mice.

Since December of 2004, I have been working extensively with a group of scientists and moral theologians in the on-going moral evaluation of ANT, beginning with a Scholars Forum dedicated to this question in April of 2005. The continuing point of moral concern (because of its conceptual proximity to human cloning) is whether it can be shown with moral certainty that this procedure would not give rise to a human embryo if done with human cells. Of course, even if that could be shown, we would require further assurances that its broad application could be pursued in a manner that would not involve the use of human eggs (thus avoiding the further ethical pitfall of creating yet another venue for the potential exploitation of women for their eggs in the name of scientific research).

Out of that April 2005 gathering arose a joint statement signed by more than 30 leading moral philosophers and theologians. We wrote at the time:

Our proposal is for initial research using only nonhuman animal cells. If, but only if, such research establishes beyond a reasonable doubt that oocyte assisted reprogramming [ANT] can reliably be used to produce pluripotent stem cells without creating embryos, would we support research on human cells

Our work on this issue has generated both hope and controversy-a good deal of which was chronicled in an article in the January 2006 issue of Crisis magazine.

We will rightly remain cautious on ANT until further research on animals (particularly on primates) can give us greater assurance that the product of ANT would not be an embryo-that, of course, remains the crucial moral question. Only further animal research, coupled with continued philosophical and theological reflection, could potentially afford us a reasonable degree of moral certainty that ANT pursued with human cells would not render a human embryo.

The value of ANT, if it can be shown to be ethically acceptable, lies in what it offers science: (1) a reliable source of stem cells (essentially equivalent to normal human embryonic stem cells); (2) a reliable method for generating patient-matched cells for growing replacement tissues (in other words, an acceptable substitute for so-called 'therapeutic cloning'); and (3) a workable platform (the ANT product) for pursuing other kinds of research not immediately related to the search for cures.

Over the past two years, I have seen growing indications that not a few scientists, preferring to avoid the moral controversies entailed by embryo-destructive research, would be satisfied with just such an alternative.

So, here at the Institute, our moral analysis of ANT is on-going. The prospect of a future in which the human embryo constitutes the research platform of choice for the biotech industry compels us to consider ANT and all the proposed alternatives with principled and rigorous moral analysis. We sustain the hope that our on-going analysis of these alternatives, coupled with absolute respect for human life, will lead us to clear determinations about morally acceptable solutions.

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