Embryonic Stem Cells: The Future Of Organ Transplants

Human embryos growing in laboratory test tubes seems like a scene from an Alien movie. However, human embryos are routinely cultured by infertility clinics in laboratory dishes. Eggs and sperm are mixed and grown to the blastocyst stage, which is anytime between fertilization and the 100-cell stage. If desired, these cells can be implanted back into a human uterus and grown into a new individual. Any of the embryos created by the procedures will eventually be destroyed if they are not donated by the consenting parties for research. The cells of these embryos offer a medical potential beyond belief, however, in terms of organ regeneration and other types of disease cures.

Dr. Roger A. Pedersen is one such researcher who believes in laboratory research on human embryos as legitimate scientific work; therefore, he feels it should be supported by the public and governmental agencies. He further states that the embryos obtained from the donors should be used only with the consent of the donors.

What We Need to Know

Are there any organs present in the blastocyst stage of development? Is the nervous system functional? Are there any brain waves?
Can you describe how you would distinguish between destroying excess embryos routinely developed in infertility clinics and destruction by research methods?
How are eggs and sperm procured to mix in vitro at infertility clinics?

In 1994 a panel of ethicists and scientific researchers met at the National Institute of Health in Bethesda, Maryland, to study the issue of "science meets ethics." The U.S. congress has since banned federal moneys being used for research on human embryos; however, that has not stopped private corporations from supporting the work of those such as Dr. Pedersen. A corporation known as Geron Corporation in Menlo Park, California, is one such company that supports workers like Dr. Pedersen.

Dr. Pedersen draws the line at cloning human beings, however, and has spear-headed a moratorium on reproductive cloning of humans which has been endorsed by all U.S. scientists who could potentially do that type of research.

What We Need to Know

What is the scientific difference between cloning and research on human embryos?
Why might a person like Dr. Pedersen support a moratorium on human cloning, yet continue to work on human embryos?
What might be the consequences of corporate support of that type of research?

Now, it is thought that embryonic stem cells offer a chance to grow tissues in a test tube without the moral dilemmas. How is that possible? Embryonic stem cells are derived either from a natural embryo or from one produced through somatic cell nuclear transfer. That way, these cells are no longer equivalent to an embryo which can develop into an entire new individual and are not considered potential humans.

In order to grow stem cells in vitro, scientists have to alter the blastocyst by excising cells which are essential to the development of a placenta, hence strip away the possibility that the remaining cells can even develop in a human uterus.

What We Need to Know

What cells of the blastocyst develop into the placenta? Which ones develop into the embryo?
Why are the embryonic stem cells valuable for their medical potential?
What are somatic cells as opposed to germ cells?
What is the procedure known as somatic cell nuclear transfer? In what types of research is it used? How does it differ from cloning?

Assignment

There are a number of moral and ethical considerations raised by the information presented in this case study. With a partner, discuss the issues raised. Answer the following questions after having done some research on the case presented.

If a couple is infertile, would your ethics permit them to undergo in vitro fertilization knowing that some embryos will be destroyed?
Would your ethics permit the couple to donate unused embryos for medical research, knowing that the outcome could save hundred of lives and prevent suffering?
Do the precautions used in stem cell research allow you to ethically justify embryonic tissue research?
Do you feel that the U.S. government, rather than corporate funding, should support research on embryos?
Do you feel that the U.S. government should ban all fetal tissue research, knowing the potentials for medical breakthroughs? If you could save your own dying child as a result of this type of medical research, would you permit the embryonic tissue research?

RESOURCES

Pederson, Roger A. 1999. Embryonic stem cells for medicine. Scientific American. April, pp. 68-73.

Thomson, J.A., et al. 1998. Embryonic stem cell lines derived from human blastocysts. Science. Vol. 282:1145-1147.

http://www.faseb.org/opar/cloning.moratorium.html

http://www.cwfa.org/library/life/2000-05_pp_stem-cell.shtml

http://www.stemcellresearchnews.com

http://www.sigmaxi.org/amsci/articles/99articles/Wright.html