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. 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." 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." 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. 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. 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: 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.
At present, there is adequate available tissue from elective abortions to meet the
need of Parkinson's disease patients. 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.
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
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." 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. The initial
success reported in these countries was not confirmed in the United States,
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 and in the United States, 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.
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. 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." 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.
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.
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.
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. However, eight
states (Arizona, Arkansas, Illinois, Indiana, Louisiana, New Mexico, Ohio, and
Oklahoma) prohibit the use of fetal tissue from dead fetuses, and seventeen
states prohibit the sale of the tissue and fetal organs. 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.
The current discussion on this issue began in October 1987