By Leon R. Kass
Tuesday, July 12, 2005
The stem cell wars have heated up again, with the next skirmish due shortly on the Senate floor. Once again scientists and patients' advocates, eager to garner maximum support for this promising field of research, are urging Congress to overturn the current limits on federal funding for embryonic stem cell research; a bill that would do so was passed by the House and is up for a vote in the Senate. Once again, pro-life advocates and their fellow travelers, dismayed at our increasingly utilitarian approach to nascent human life, oppose rewarding additional embryo destruction with further liberalization of federal funding for embryo research.
Both sides of this quarrel have something vital to defend, not only for themselves but for all of us. No decent society can afford to be callous to human suffering or indifferent to the need to seek cures. No decent society can afford to treat human life, at whatever stage of development, as a mere natural resource to be mined for the benefit of others.
Neither side is going to go away, nor should they. Far-sighted people can see that this is but the first of a long series of similarly contested bioethical issues. Yet it would be a pity if our only options were either a political victory for one side that would seriously alienate the losers, or a continuing political stalemate.
Fortunately, there is a third way, one that deserves to be vigorously pursued. A growing number of reports are beginning to suggest that science may find a way around the impasse: a method of producing the same kind of cells, but without destroying embryos.
Embryonic stem cells hold special interest because of two properties. They can give rise to most if not all of the more specialized cells of the body (they are "pluripotent"). And they can be grown in laboratory culture for long periods without losing their pluripotency (they are stably "self-renewing"). But recent scientific reports suggest that there may be ways to derive pluripotent and self-renewing human cells -- the functional equivalent of embryonic stem cells -- without having to destroy human embryos in the process.
Four such approaches were surveyed and discussed in a recent report from the President's Council on Bioethics, "Alternative Sources of Human Pluripotent Stem Cells." Pluripotent cells might be obtainable from already dead (not just unwanted or doomed but actually dead) embryos, some of whose individual cells might nonetheless still be viable; from living embryos by nondestructive biopsy; from bioengineered, embryo-like artifacts; and from reprogrammed body cells, taken from children or adults, that are induced to return to the undifferentiated state of pluripotency.
It is too early to know which of these approaches will prove most successful, or whether some alternative approach will be superior. And, as the council noted, these proposals raise some ethical questions of their own. But recognizing the benefits of an approach to deriving pluripotent stem cells that all Americans would welcome and that the federal government could support, several scientists have already started to pursue these new techniques.
Indeed, since the council report was released, new evidence suggests that alternative sources may be available sooner than we thought even two months ago. Researchers here and abroad have reported exciting early successes, especially with the ethically unproblematic approach of reprogramming differentiated cells back to the stem cell condition by means of a technique called cell fusion.
By fusing an adult cell with an existing embryonic stem cell, scientists have reported progress toward producing cells that are genetically identical to the adult cell but that retain stem cell properties. An Australian group has succeeded in doing this in mice. A Harvard group, working with human cells, has produced hybrid cells with many stem cell properties. And Yuri Verlinsky's team at the Reproductive Genetics Institute in Chicago, working with human cells, claims to have succeeded altogether; he has submitted a patent application that tells us how he did it.
The merits of this approach are great. You would get stem cells of every available genotype, permitting studies of the molecular basis of genetic diseases. Way down the road, you might get individualized cell-based therapies -- all the advantages of cloning-for-research but without the need for eggs and without creating embryos. And this research is eligible for federal funding under President Bush's existing policy. These fusion experiments could be carried out using any of the 22 human stem cell lines that are eligible for federal funding under the Bush policy and that are today available from the National Institutes of Health.
Other avenues to adult cell reprogramming and other alternative sources are being pursued in the laboratory, though still with no concrete results. The creative search for alternatives has only just begun in earnest. Yet some scientists and cynics claim that this attention to alternative sources is merely a ploy to deflect attention from the need to fund embryo research.
It may be that some opponents of embryo research are using these worthy proposals for such a political purpose. It may be that some scientists, for their own political purposes, are decrying the new approaches, despite the exciting new evidence. But every public-spirited American should be encouraged by these findings. We should be hopeful that a technological solution to our moral dilemma might soon be found and that this divisive piece of our recent political history will soon come to an end.
Senators will be given a chance this week to enact legislation to increase funding for alternative sources. They should not miss this timely and most promising opportunity for scientific and ethical statesmanship.
The writer is a fellow at the American Enterprise Institute and chairman of the President's Council on Bioethics.