AN INTRODUCTION TO FETAL TISSUE TRANSPLANTATION
Rod Harris, Ellen Mayo, Jim Tankersley
To make a reasoned decision regarding fetal tissue transplantation, students need to master basic factual information, formulate and justify their opinions, and consider the consequences and values associated with their solutions.
Grades 9-12; biology or advanced life science course, or bioethics course; some modification may be necessary for specific classroom constraints.
Students will be able to discuss the scientific background regarding fetal tissue transplantation after reading handout materials and completing library research.
Students will be able to verbalize questions regarding ethical issues related to fetal tissue transplantation.
Students will be able to develop and defend ethical positions related to fetal tissue transplantation.
Student copies of attached background information sheets, the pre-test, and research questions; access to a library; time for individuals and groups to work together.
Suggested Time Frame:
4-5 class periods (may be extended)
Students complete pre-test and read background material. Teacher assigns groups, if applicable.
Students use library resources to complete research questions. NOTE: This may be continued for several days or assigned for time outside of class, at the discretion of the teacher.
Students will share answers to questions with the class in a discussion format. Any variations in factual responses should be referred for further research and verification to resolve with accuracy before proceeding to analyze questions involving values.
Assignment: Each student is to write a two-page paper discussing his/her position regarding fetal tissue transplantation. This should take the form of a policy statement, addressing any limitations that should be placed on work in this area as well as how those limitations will be enforced and by whom. Each point must be supported by evidence or statement of a particular value that has been applied and an explanation for why such application is appropriate. Finally, the statement should conclude with an assessment of who is being helped or protected by this policy and how, as well as any negative effects of this policy.
Optional Final Day:
Students will present their policy proposals to a government panel for consideration. The panel will select one policy or a combination of elements from several proposals to publish as the "official" class policy regarding fetal tissue transplantation. Dissenting opinions may be included in the final class product.
Teacher Note: OPTIONAL EXTENSION for advanced students with experience in bioethical considerations:
Students will compare their own responses on the pre-test and their policy proposal to examine changes in their knowledge and thought. The teacher will evaluate the policy statement in terms of the clarity of the statement and the support provided for their reasoning. Teachers of younger students may wish to separate the activity into smaller components, one of which might include research, and assess each component separately to emphasize the various skills employed throughout the activity.
Background Information: Fetal Tissue Transplantation
Much human suffering results from degeneration of neural tissue, either from aging, disease, or accident. Once damaged, most human neural tissue will not regenerate, so repair to damage in the spinal cord, brain, and other neural areas is severely limited. Scientists have been trying for years to find ways to trick the neurons into repair and regrowth. Barring regeneration of the original tissue, some scientists have recently been attempting to transplant healthy neural tissue into areas where significant damage has occurred, allowing the re-establishment of damaged neural circuits. There have been several barriers to be overcome, including development of the technical expertise to remove and transplant such tissue without causing damage to it or to other tissues in the host, and the subsequent immunological complication that results whenever any foreign tissue is transplanted into a human.
These problems may be solved through the use of fetal tissue. A fetus is a developing human, 8 or more weeks after conception. In the early months after conception, fetal tissue is rapidly growing and has very little antigenicity, i.e., it has little ability to induce an antibody response because it has not yet developed many surface antigens. The tissue is not fully differentiated and will adapt fairly well to the signals received from surrounding tissue in a host, growing and differentiating to function as part of the host organ. In addition, it can be successfully cryopreserved and reanimated.
Research has been done using fetal tissue in many different ways. Study of spontaneously aborted fetuses has taught much about birth defects and has added to our ability to diagnose and treat fetal disorders. Congenital defects are seen in 3 to 5 percent of live births in the U.S. annually. Immortal fetal cell lines have been developed for study of gene regulation, pattern formation in embryogenesis, models of cell interaction and function, vaccine development, cell growth and regulation, cancer, and the immune response. In addition, fetal cell lines can be used for screening pharmaceuticals for teratogenicity and carcinogenicity, an essential step before clinical trials can be pursued.
The greatest furor, however, has developed around the transplantation of fetal tissue from induced abortions into adult hosts. Mesencephalic dopamine neurons obtained from fetuses of 8 to 9 weeks gestational age can survive in the human brain and produce marked and sustained symptomatic relief in a patient severely affected by idiopathic Parkinson's disease. Clinical trials with transplanted fetal mesencephalic tissue have been initiated in patients with Parkinson's disease since 1989 with approximately 100 patients. Research indicated that some symptomatic improvements were observed, but it is not certain whether the improvements were due to the fetal tissue itself or from nonspecific aspects of normal surgical intervention. It is presumed that the symptoms of Parkinson's disease are offset by the increased production of dopamine in the brain.
Other work has involved grafting fetal tissue into the brains of patients suffering from Huntington's disease. This is a much more complex situation in which actual micrografting of neurons is required. Although work with animal models has shown great promise in Huntington's, there is conflicting data resulting from the few human trials that have been completed. Nonneural fetal tissue transplantation has included injection of immune cells from the thymus and liver of two aborted fetuses into the umbilicus of a 30-week-old fetus with bare lymphocyte syndrome, a rare and always fatal immunodeficiency disorder. Following a second, postnatal injection, the infant showed development of immune tissue in the spleen and liver as well as marrow proliferation. Other uses of fetal tissue might include treatment of diabetes as well as optic and spinal cord disorders such as paraplegia resulting from accidents.
Such tissue must be taken from a living fetus, however. Fetal material recovered from spontaneous abortion is often deoxygenated and damaged beyond usefulness. Thus, the primary source of such tissue has been from elective abortions, which is the cause of much of the debate regarding use of fetal tissue. Those who believe that abortion is immoral are also not in favor of using fetal tissue. For purposes of this activity, it will be assumed that abortion is a separate issue. Consider only the issues regarding the fetus itself: is it a separate moral agent? Is it alive? Who has the right to determine whether or not to use fetal tissue? Who benefits from the use of fetal tissue? Who is harmed? How should this type of work be regulated and by whom?
NAME________________________ CLASS________________________ PERIOD_______________________
DIRECTIONS: COMPLETE THE FOLLOWING QUESTIONS NOW, BEFORE DOING ANY READING OR RESEARCH ON FETAL TISSUE TRANSPLANTATION. YOU MAY USE THE BACK OF THIS SHEET, PROPERLY ANNOTATED, IF YOU NEED MORE SPACE.
Barinaga, Marcia, v 234 Science Nov. '91 p1100 " Current Research Using Fetal Tissue for Huntington's Disease"
Beauchamp, Tom L. and Leroy Walters. Contemporary Issues in Bioethics . Belmont, CA: Wadsworth Publishing Company, 1989, pp 122-149.
Freed, William J. et al. v 250 Science Dec. 7 '90 p 1434 (2) "Fetal Brain Grafts and Parkinson's Disease"
Hensen, John T. and John R. Sladek, Jr. il v246 Science Nov. 10 '89 p 775 (5) "Fetal Research"
Lindvall, Olle et al. v247 Science Feb. 2 p 574 " Grafts of Fetal Dopamine Neurons Survive and Improve Motor Function in Parkinson's Disease"
Marwick, Charles v 261 JAMA Jan. 20 '89 p342(1) "Ban to be Lifted on Research Use of Fetal Tissue?"
McCullagh, Peter. The Foetus as Tranplant Donor: Scientific, Social, and Ethical Perpectives. Chichester: John Wiley & Sons, 1987.
Sladek, John R. Jr. and Ira Shoulson v240 Science June 10'88 p1387 (3) "New Hope for Neurotransplants: A Call for Patience Rather than Patients"