TCS Daily


Petri Politics

By Sydney Smith - August 24, 2004 12:00 AM

The stem cell debate recently took its place in Presidential campaign politics. Senators Kerry and Edwards mounted a full frontal assault, accusing the current Administration (apparently without irony) of playing politics with science. Politics and stem cell science aren't strangers. Far from it. It's a branch of science that has been heavily politicized from the beginning. And like all heavily politicized topics, there's been much obfuscation of the true issues behind the debate.

To begin with, contrary to the Kerry campaign's assertions, there is no ban on embryonic stem cell research. Scientists are free to experiment on all the embryonic tissue they want. They just can't use taxpayer money to do it, at least not if it involves the creation or destruction of a human embryo. Unfortunately, embryonic stem cell research involves both.

Embryonic stem cells are found only at the earliest stages of human development, when the embryo is a spherical mass of about 200 cells. These cells are blank slates with the potential to grow into any type of mature cell -- nerve cells, heart cells, pancreatic cells -- the potential is limitless. To produce usable stem cells, the inner cell layer is removed from the embryo and transferred to a petri dish, a process which destroys the embryo. The cells are then manipulated chemically to alter their gene expression in the hope that they will specialize into cells of some use.

So far, human embryonic stem cell cultures have been successfully and reliably coaxed into becoming nerve cells and heart muscle cells. (Other stem cell specializations have either not been reproducible or have only been done in animals such as mice.)

(There are two other types of stem cells worth mentioning -- non-embryonic, or "adult" stem cells found in bone marrow, blood, and umbilical cords of children and adults, and embryonic germ cells from five to nine week old aborted fetuses. Because neither of these is subject to federal funding restrictions, their contribution to stem cell science and to stem cell ethics goes largely ignored.

The greatest hope of embryonic stem cell research is that some day stem cells will cure disease. They will become the nerve cells that make the paralyzed walk, the pancreatic cells that overcome juvenile diabetes, or the neurons that cure Parkinson's disease. To do this, they will have to be transplanted into the diseased tissue. And, like any other transplant, they will run the risk of rejection by the recipient's immune system. Although stem cells are presumably less potent stimulators of the immune system than full grown cells, when they become specialized enough to cure disease, they also become specialized enough to provoke rejection.

There is a way around this. It's called somatic cell nuclear transfer (SCNT), or therapeutic cloning. Merging the DNA of the patient with a donor egg, creating an embryo that's genetically identical to the patient, and harvesting the stem cells from that embryo drastically reduces the chances of rejection of therapeutic stem cells. It is a procedure which creates an embryo for the sole purpose of destroying it -- a proposition which many find disturbing in and of itself, but also because SCNT is the same process by which fully functioning human clones may be created. Proponents of therapeutic cloning argue that the embryos created with this technique are of such poor quality that they have no potential to ever grow into a functioning human being. Opponents note that may be true of today's technology, but what of tomorrow's?

The other obstacle in embryonic stem cell research is a matter of supply. Today there are 128 embryonic stem cell lines in the entire world (22, or 17%, of these lines are eligible for federally funding today, far more than the 0.1% that the Kerry campaign has claimed). As described in one recent paper, the production of just 17 stem cell lines required 286 embryos. There are an estimated 400,000 frozen embryos in fertility clinics in the United States, but only three percent are unwanted, and thus available for research. According to the Rand Institute, that translates into just 275 potential stem cell lines. If cast away embryos can't fulfill the need, then they would have to be created in the lab, either through cloning or in vitro fertilization. Either way, an embryo is created and destroyed for the sake of science.

And like it or not, a significant portion of the population has reservations about committing their hard earned tax dollars to such a venture. Which is why restrictions on federal funding of research that involves the creation or destruction of a human embryo have in been in place since 1995 -- three years before embryonic stem cell cultures became a reality.

For the first time in history we are confronted with the possibility of using the seeds of the next generation to cure the ills of the present. And that deserves an honest debate and examination of our values, not a politicized one.

The author is a TCS contributor. A family physician who has been in private practice since 1991, she is board certified by the American Board of Family Practice, and is a Fellow of the American Academy of Family Practice. She is the publisher of MedPundit.


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