Spare Parts From the Unborn?

The Ethics of Fetal Tissue Transplantation

by Scott B. Rae

On November 10, 1988, surgeons at the University of Colorado Medical Center implanted fetal brain cells into the brain of a 52-year-old victim of Parkinson's disease, Don Nelson.[1] Following the surgery, Nelson reported some improvement in his ability to walk and speak. Since more conventional treatments had not been effective, the use of human fetal tissue was the only option left for alleviating some of the symptoms of Nelson's Parkinson's disease. However, the tissue was taken from a fetus who had been aborted for birth control reasons.

There is currently great excitement in the medical community about the prospects of fetal tissue transplantation. Abraham Lieberman of the New York University Medical Center put it this way: "Fetal tissue transplantation is to medicine as superconductivity is to physics."[2] Yet, Arthur Caplan, Director of the Center for Biomedical Ethics at the University of Minnesota, has called the ethical dimensions of this issue "the ticking time bomb of medical ethics."[3] Although no one denies the urgent need to help people suffering from degenerative diseases, serious questions are being raised about the source of the tissue.

Fetal tissue transplants are actually part of a long-established tradition of using fetal cells in research. For example, the 1954 Nobel Prize for Medicine was awarded for a polio vaccine that was developed from fetal kidney cells. In addition, fetal cells were used in the production of a widely used vaccine for measles.[4] In the early use of fetal cells, however, the source of the cells was limited to spontaneous abortions and ectopic pregnancies (see glossary), not elective abortions done for birth control purposes.

Fetal tissue is a good source of transplant material due to its potential for growth, its ability to differentiate (see glossary), and its ability to integrate into the recipient. It is also less subject to rejection in the transplant process.[5] In addition, it is currently in high supply.

There are many potential uses for fetal tissue transplants, but the focus to date has been on the treatment of Parkinson's disease and diabetes. Using Parkinson's disease as an example, where the technology is most advanced, here is how a transplant of fetal tissue alleviates some of the symptoms:[6] Parkinson's disease affects the part of the brain known as the substantia nigra. When the neurons there begin to disintegrate, the production of dopamine is impaired. This is the chemical that is necessary for the brain to generate both the walking and speaking functions. As a result, the patient experiences motor difficulty, rigidity, tremor, and even dementia, eventually rendering him or her unable to carry on any normal functions. As is the case with all neurological diseases, the tissue that is destroyed cannot be renewed. To treat the disease, the brain tissue from a human fetus is transplanted into the brain of the patient and within weeks the tissue begins to secrete dopamine. This represents an alternative to the customary drug therapy that contains dopamine or stimulates greater dopamine release from the existing healthy tissue in the brain.[7]

At present, there is adequate available tissue from elective abortions to meet the need of Parkinson's disease patients.[8] However, should the technology develop as anticipated and be effective in treating a wide variety of degenerative diseases, the amount of tissue would fall far short of the demand.[9]

GLOSSARY

Bioethics: The study of ethical issues in medicine and the life sciences.

Cell Culture: A process by which cells are "manufactured" to suit a specific medical purpose.

Differentiation: The ability of cells to develop the different functions necessary to perform their particular roles in the body.

Ectopic Pregnancy: A pregnancy in which the fetus implants in the fallopian tube instead of the uterus.

Neuroblastoma Cells: Neurological (brain) cells that are cultured for use in treating degenerative neurological diseases.

Roe v. Wade: The 1973 U.S. Supreme Court decision that legalized abortion on demand during the first two trimesters of pregnancy.

STATE OF THE SCIENCE

The best way to characterize the state of fetal tissue transplant technology is "experimental."[10] This area is one of the few in bioethics in which the ethical discussion is ahead of the medical technology. It is encouraging to see the amount of ethical reflection that is taking place while the science is still being developed.

One method of treating Parkinson's disease that does not involve fetal tissue was attempted by researchers in both Sweden and Mexico who transplanted cells from the patient's own adrenal glands that also secrete dopamine.[11] The initial success reported in these countries was not confirmed in the United States,[12] which has raised skepticism about the accuracy of these early reports, particularly the experiments in Mexico.

Animal experiments with fetal tissue have, however, met with considerable success. Again in Sweden[13] and in the United States,[14] transplants of fetal tissue into rats have shown that the tissue, when transplanted, does find its way to the section of the brain that matches its physiological function. These advances were expanded when a 1986 experiment showed success in using fetal tissue in treating Parkinson's disease that had been induced in monkeys.[15]

The success with human recipients has not been as clear-cut, however. To date there have been only a handful of transplants performed on human beings in the United States. Don Nelson's transplant in November, 1988 was the first, followed by a similar operation at Yale University Medical School one month later. At the November 1988 annual meeting of the Society for Neuroscience, most of the researchers conceded that the recipients have received little clinical benefit; they called for more research on animals.[16] Anders Bjorklund of the University of Lund in Sweden, who performed transplants on two Parkinson's patients in 1987, reported at that meeting that "the results have not been impressive" and "the implantations have not had any clinical significance."[17] Though most researchers are optimistic about its eventual success, there are sharp differences of opinion on the timetable, and some call for more extensive animal research prior to moving forward on human beings.[18]

Should the technology be perfected, it shows promise for application to a number of other degenerative diseases such as Alzheimer's disease, Huntington's Chorea, and spinal cord or other neural injuries. In addition, the use of fetal liver cells shows promise for treating bone marrow diseases and blood disorders, and fetal pancreatic cells have been shown to help treat diabetes.[19]

STATE OF THE LAW

In the aftermath of Roe v. Wade, the federal government established regulations to limit the scope of experimentation on the fetus. In 1974, the Department of Health, Education and Welfare (HEW) created the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research. The regulations recommended by this commission were adopted the following year. Experiments on the live fetus are permitted only if the research is of benefit to the fetus and if there is minimal risk to it. In cases where critical information cannot be obtained from any other source, nontherapeutic research is permitted as long as the risk to the fetus is minimal. Ironically, these regulations protect the fetus, as a subject of experimentation, in almost the same way adults are protected. Yet, the Roe decision denies the fetus the right to life throughout the first two trimesters. Most state laws restrict experiments on live fetuses (as do the HEW regulations), and the majority of states follow the federal regulations, with charges for violation ranging from misdemeanor to homicide.[20]

The regulations further state that any experiments with dead fetuses be done in accordance with state law. Most states permit the use of tissue from dead fetuses under the provisions of the Uniform Anatomical Gift Act, which allows next of kin to donate the tissue, similar to organ donation from cadavers.[21] However, eight states (Arizona, Arkansas, Illinois, Indiana, Louisiana, New Mexico, Ohio, and Oklahoma) prohibit the use of fetal tissue from dead fetuses,[22] and seventeen states prohibit the sale of the tissue and fetal organs.[23] The law in Louisiana has been successfully challenged on the constitutional grounds that it unduly restricts a woman's right to an abortion. It should be noted, however, that the law was struck down due to its ambiguity, not any problem in principle.