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Ethical concerns surround stem-cell research

June 14, 1999
Web posted at: 5:48 p.m. EDT (2148 GMT)

By Hacsi Horvath

(WebMD) -- A scenario: You have severe congestive heart failure. You need a heart transplant, and your doctor tells you that due to the scarcity of replacement hearts, you might have to wait a year or more. After the transplant, your body's immune system might still reject the new heart. Even if the transplant is a success, you will have to endure the effects of immunosuppressive drugs for the rest of your life.

Another scenario, this one for the future: You have severe congestive heart failure. Your doctor admits you to the hospital. During an operation later that day, she injects some heart cells into your heart, and after an integration period of a few days, your heart is substantially healed. You go home and lead a healthy life.

The second scenario sounds great, doesn't it? What if you knew that the heart cells were generated from human stem cells, taken from human embryos? Depending on your beliefs about when life begins, this might bother you a great deal, or it might not bother you at all.

Embryonic human stem-cell research was discussed recently in San Francisco at an American Medical Association media briefing on genetics. The stem-cell scenario is one researchers hope will become real early in the 21st century, not just for diseased hearts but for livers, kidneys and lungs. By the very nature of the research, however, they have found themselves enmeshed in a debate that has divided America for decades -- the question of when a fertilized human egg becomes a living being.

What are stem cells?

Stem cells are the undeveloped ordinary cells of very early-stage (no more than 64-celled) embryos. (A newborn baby, in contrast, consists of billions of cells.) Many of these embryos have been grown in a laboratory from fertilized eggs; they were produced for in-vitro fertilization but were later discarded or donated specifically for research purposes. Embryonic stem cells are pluripotent, which means that unlike more mature cells, they hold the possibility of developing into any organ of the body. Scientists experimenting with mice have introduced pluripotent mouse embryo stem cells into diseased organs. These stem cells begin to take on certain characteristics of the organ cells.

The stem cells don't actually develop into organs, but they do begin to resemble the organ cells; stem cells introduced into a diseased kidney, for example, become much like ordinary kidney cells. The other kidney cells "educate" and integrate the new cells until the organ is effectively regenerated.

Possibilities in the medical future

This ability to grow human tissue of all kinds may make it possible to cure numerous cell-based diseases like juvenile-onset diabetes and Parkinson's disease, and to make organ transplants unnecessary. Failing hearts and other organs, in theory, could be brought back to health by injecting these pluripotent cells into damaged or diseased tissue.

Many people, however, hold deep concerns about the research with human embryos and the possibility of its application in everyday medical practice. According to Dr. David R. Cox, professor of genetics and pediatrics and co-director of the Stanford Human Genome Center at Stanford University, "A significant fraction of people in our country believe that developing human stem cells from early pre-implantation human embryos is destroying human life."

Ways to compromise

Cox believes that there are "intermediate positions" in research, ways to continue doing basic science while addressing the concerns of people who believe that this type of research should not be conducted under any circumstances -- by using human embryos that otherwise would have been destroyed or thrown away, for example. Another intermediate position is to have an ongoing assessment of the research results. "If it's being done because of the medical benefit," Cox said, "then let's make sure the medical benefit is happening."

It may be possible to balance the needs of medical research with the deep-seated beliefs of millions of people. Cox said the best process to reach this balance would be a public dialogue. "What is needed now are public discussions to define those outcomes that we would like to avoid and those outcomes that we would like to see happen. Then we can worry about the best mechanism to implement those goals."

Copyright 1999 by WebMD, Inc. All rights reserved.



RELATED AT WebMD:
Human Gene Research


RELATED STORY:
Ethics Matters: Embryonic Ethics
June 1999

RELATED SITES:
The Human Genome Project
National Human Genome Research Institute
Oh What a Beautiful Blastocyst: Embryonic Stem Cell Research
American Medical Association
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