Dr. Jeff Kahn: Ethics of stem cell research
Jeffrey Kahn is the director of the Center for Bioethics at the University of Minnesota. He is a professor in the university's schools of medicine, and public health and philosophy. Kahn's recent book is "Beyond Consent: Seeking Justice in Research." He writes a bi-weekly column about ethics for CNN Interactive.
CNN: Good afternoon Dr. Jeff Kahn. Welcome to CNN.com Newsroom.
KAHN: Hi, everybody! Happy to be here.
CNN: What exactly are we talking about when referring to stem cells?
KAHN: Well, actually, there are two kinds of stem cells that we're talking about. There are adult stem cells, which are like in the bone marrow, which can become any other kind of cell within a particular area of the body. For example, in the bone marrow, stem cells can become any other kind of blood cell, but they can't become liver or nerve or heart, or other kinds of tissue.
So, the kind of cells we're arguing about are called embryonic stem cells, which are cells that can become any other kind of cell in the body. They're more potent than other stem cells. They're much more controversial because of the source. They come from human embryos, and human embryos are destroyed in the process of collecting them.
CHAT PARTICIPANT: Is there any solid progress or reason to consider continuing this research?
KAHN: Yes, there is lots and lots of progress, first in animal models. There has been promising research showing that these cells can be used in lots of therapeutic applications. For instance, the likely first step would be things like Alzheimers or Parkinson's Disease, where stem cells could be implanted into the brain, and replace the diseased cells or the cells that don't work properly. And then if we look further out, people have suggested that we could actually repair spinal cord injuries in people like Christopher Reeve, or grow human organs for transplant purposes.
So, the step between where we are now and getting to these applications, is taking these cells and learning how to program them to become the target cell that we want. That's what this research is all about, getting to that kind of understanding, so we could actually use these cells for therapeutic purposes.
CHAT PARTICIPANT: Thank you Dr. Kahn for being here - can you please discuss the types of ways embryonic stem cells are collected currently?
KAHN: Embryonic stem cells all come from human embryos. What happens is that they're very early stage after fertilization. Most have come from leftover embryos from invitro fertilizations. Those embryos are just a few days old, just a few hundred cells total. They have embryonic stem cells within those cells, and they're harvested from the embryos, which destroys the embryo in the process. You can't just take the cells, and then have the embryo normally develop.
CHAT PARTICIPANT: Please clarify - are we talking about the embryos from abortions or those artificially inseminated that go unused?
KAHN: The latter. There aren't such things as embryos from abortions, because an abortion happens much further along in gestation. Two years ago, when embryonic stem cells were first identified, the two sources were human embryos and tissue from aborted fetuses. An area called the neural ridge in a developing fetus has cells that are very similar to embryonic stem cells, but most scientists now believe that stem cells from embryos are of superior quality, so that's become the focus of the source of stem cells, rather than aborted fetal tissue.
CHAT PARTICIPANT: Why is everybody asking if this is ethical? Who exactly is getting hurt since we do still allow abortions?
KAHN: The concern is that it violates the moral status of human embryos to destroy them for research purposes. It's not exactly like abortion, because it's not inside a woman's body. Much of the abortion debate revolves around the right of women to choose what happens to their body, but these are embryos in a test tube. The question is who has the right to decide what will happen to these leftover embryos.
CHAT PARTICIPANT: What normally happens to these used embryos if they are not used for research?
KAHN: Great question. Here's a list: They can remain frozen. They can be donated to another couple. They can be donated for research purposes. They can be discarded. Or they can be used by the couple that created them in the first place.
CHAT PARTICIPANT: Would "parents" of the frozen embryos need to give permission for their product to be used?
KAHN: Yes. Every clinic requires the consent of the couple for any disposition of the embryos.
CHAT PARTICIPANT: Is there any chance that these stem cells embryos would become human beings if not used for the research?
KAHN: Yes, if they were implanted into a woman's uterus, and things went right, then they would become a baby. That requires a willingness to use them if they're their owned, or donate them if they're created for the purpose of having a child. But for the vast majority of those leftover embryos, that will never happen.
CNN: Are any biotech companies or researchers soliciting donors to create these embryos?
KAHN: Certainly researchers. That's the story out today about the Jones Institute. Researchers at the Jones Institute recruited women to donate eggs, and men to donate sperm for the purpose of mixing them together to create embryos for the purpose of doing stem cell research on them. Not for the purpose of reproduction. It's created controversy, because the intention was not to have a child, as in the case of IVF, but for the express purpose of destroying them in the process of research. There's a question about whether we need to do that. It's not clear, even after they published their paper, whether there's any need to do this, given we have an estimate of 200,000 embryos left over from IVF worldwide.
CHAT PARTICIPANT: Is this the first instance of embryos being created solely for the purpose of stem cell research?
KAHN: As far as we know, yes.
CNN: What kind of procedure must female egg donors go through?
KAHN: You have to take injections of hormones to stimulate what we call hyper-ovulation, so the woman would produce many more eggs than usual under normal ovulation. Then those eggs are collected by a long needle being inserted into the ovary, and removing them. There are risks from the drugs you take before hand, and risks to the procedure itself. There's some evidence that there's an increased risk of cancer in women who take the drugs for hyperstimulation of their ovaries.
CHAT PARTICIPANT: How many embryonic stem cells would have to be transplanted into a human to replace an organ or to cure their disease?
KAHN: It turns out that embryonic stem cells are immortal. That is, they'll divide forever. So, in theory, you would grow an organ in a laboratory and then transplant it into a person's body. You wouldn't put the cells into a body and have them grow in the right place. That's all very prospective, and there's a lot of research to be done. This could all change.
CHAT PARTICIPANT: Dr Kahn, do you need federal money to continue the research?
KAHN: That's a great question. People should understand that the U.S. government is the single largest funder of biomedical research in the world. It's not just a question for stem cell research in the U.S., but on the international scene. Without federal funding, it's very hard to exert federal control over this or any other area of research. It would be much easier to control this research if the federal government funds it. So those are two strong reasons why we should consider federal funding.
CNN: Do you have any final thoughts for us today?
KAHN: I think what's interesting to watch in the debate in Washington is how much this policy decision is being influenced by political considerations, rather than by issues of science and ethics. It's not the best way to make science policy. I hope that voices from the scientific community and the bioethics community have a say before the Bush administration makes their final decision about whether to fund this research.
CNN: Thank you for joining us, Dr. Kahn.
KAHN: It's been fun, as always. Thanks for having me.
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