By Father Tadeusz Pacholczyk
Special to the CS&T
This is the first column of a series where we will look at some of the new topics in bioethics, attempting to simplify the jargon and sort through some of the latest developments.
Recently, a letter was released on the Ethics and Public Policy Web site (http://www.eppc.org/publications/pubID .2374/pub_detail.asp) that dealt with making embryonic stem cells without destroying human embryos.
That technique has never been done in the laboratory. But if it were to prove feasible, it could offer a way out of the central ethical dilemma raised by human embryonic stem cell research.
Many prominent Catholic scholars signed the letter.
It proposed a new technique — called oocyte-assisted-reprogramming, or OAR for short — which would make stem cells directly, and so would not require creating or destroying human embryos.
The central objection to embryonic stem cell research is that it requires the destruction of embryonic humans who are about five days old, in order to procure their stem cells.
OAR might provide scientists with a way to make embryonic stem cells directly, without creating or destroying human embryos. Actually, the proposed OAR technique really shouldn’t be called “embryonic” at all, but “pluripotent” [meaning the cells have the capacity to develop into many different sorts of cells].
The pluripotent stem cells would be very flexible — as flexible as the stem cells you get from embryos.
So how do you use OAR to make “pluripotent” stem cells?
OAR makes use of a woman’s egg to carry out a procedure that, on first glance, looks very similar to cloning — but is not.
Suppose, for a moment, that a police officer suffering from diabetes were to donate a skin cell from his arm, and we took the nucleus of that skin cell (which contains his DNA) and placed it inside a woman’s egg, after we had taken out her egg’s own nucleus.
In other words, we would be performing a kind of “nucleus swap.”
Scientists call that “nuclear transfer,” and that is what cloning is all about.
In cloning, even though no sperm is involved, the egg-with-a-new-nucleus now divides, and grows normally as a human embryo — a new human being. The cloned embryo is special, however, because it has the same genes, and so is the identical twin brother, of the diabetic police officer.
It would be a very young clone of the officer, and if that embryo were implanted into a woman’s uterus, it could become a live-born cloned baby.
But if, from the beginning, that tiny, little embryo were denied the safe harbor of a woman’s uterus to grow in, and the embryo was instead destroyed to extract its stem cells, scientists could get immune-matched cells to treat the police officer’s diabetes.
And those immune-matched cells would be tailored to the police officer, because they came from his own, identical twin brother.
Scientists already know that identical twins can exchange organs (like kidneys) without rejecting those organs. So the stem cells from the police officer’s embryonic twin brother, in theory, could be introduced into his body without being rejected.
The moral problem in that, of course, is that you create your own twin brother (or twin sister if you are a woman) with the express purpose of killing him or her while still an embryo, in order to take and use the embryo’s stem cells.
If the OAR technique is demonstrated to be successful, it would avoid this moral problem.
Here is how:
Instead of creating your identical twin brother (or sister) for the purposes of strip-mining their stem cells, OAR would make a slightly different sort of stem cell.
The steps the OAR technique would take are the same series of steps as cloning, but there would be a big difference at the very beginning of the process.
At that early point, special genetic changes would be made in the DNA of the skin cell.
Those changes would involve turning on special master genes, which direct the specific cell to become “pluripotent,” or highly flexible — rather than completely flexible, as are the cells of an embryo.
So when the “nucleus swap” occurs, the new cell would become a kind of stem cell directly, rather than an embryo.
In other words, the woman’s egg would never be activated to have the capacity to form a human being. If the resulting cells made by OAR were to be inserted in a uterus, nothing would happen — no pregnancy would be possible, since they would be stem cells, not embryos.
Only embryos are capable of implanting into the wall of the uterus in making a woman pregnant.
And since OAR stem cells are not derived from embryos — and are not embryos, themselves — it would be morally permissible to culture and grow them or manipulate them in the lab as needed, in an attempt to come up with new therapies for patients.
So the advantage with the OAR stem cells would be the same as for cloning: The stem cells that resulted from OAR would be immune-matched to the police officer, and in theory should not be rejected by his body if they were transplanted into him.
OAR still remains a concept at this time. But studies should be funded to look at the procedure in animals, to assure that it is technically feasible, and to assure that it can be done without making embryos and without crossing any moral lines.
Some people might argue that we should not promote any research that makes it even remotely appear that we support embryonic-type stem cell research — given that so many remarkable successes in treating human patients are already happening using morally acceptable umbilical cord and adult stem cells.
It is true, of course, that embryonic stem cells have not yet cured even a single human, while adult stem cells have successfully treated thousands of patients suffering from more than 50 types of ailments.
It is also true that there are no clinical trials in humans yet using embryonic-type stem cells, while there are more than 200 clinical trials already underway using various kinds of adult stem cells.
All of this reminds us how adult stem cells are indeed likely to provide the most effective route to the largest numbers of cures in the future. And it also reminds us how such research should be vigorously funded and encouraged.
But it may turn out that umbilical cord and other adult-type stem cells may not be able to do the job for every disease, and embryonic-type stem cells might end up being able to work in a few cases.
If that day comes, and we have been proactive in examining and encouraging morally acceptable alternatives for obtaining pluripotent stem cells, without destroying embryos, we will all be better off.
Father Tadeusz Pacholczyk, Ph.D., is a priest of the diocese of Fall River, Mass., and serves as the Director of Education at The National Catholic Bioethics Center in Philadelphia.