THE STEM CELL HASSLE.
a. Presentation of issues.
b. Two Perspectives.
PRESENTATION OF ISSUES.
In the Year in Review by Lori P. Knowles and Eric Parens from the Encyclopedia Britannica we find an excellent presentation of issues related to the stem cell hassle of today. The text can be seen online (http://www.eb.com/) Here is a slightly simplified version of the text.
At the end of 1998, almost simultaneously, one team of researchers announced that it had isolated human embryonic stem (ES) cells and another announced that it had isolated human embryonic germ (EG) cells. These announcements gave rise both to the promise of great medical benefits and to contentious ethical and policy questions. The medical promise of these cells is the potential to provide an endless supply of transplantable tissue. The ethical and policy questions primarily concern the embryonic and fetal sources of these cells. To understand both the promise and the ethical issues, it is important to understand some basic scientific facts about ES and EG cells.
The announcement of the isolation of ES cells was made by James A. Thomson at the University of Wisconsin at Madison. Thomson and his colleagues isolated ES cells from embryos created in a fertility clinic by in vitro fertilization that are no longer needed for transfer to a woman. These embryos, five to seven days old, are called blastocysts. The outer layer of the blastocyst is destined to become the placenta. The remainder of the blastocyst, called the inner cell mass, is destined to become the fetus. Embryonic stem cells are isolated from this inner cell mass.
John Gearhart at Johns Hopkins University, Baltimore, Md., announced the isolation of EG cells. Gearhart and his colleagues isolated EG cells from five- to nine-week-old aborted fetuses. Such cells are referred to as embryonic germ cells because they come from a small set of stem cells that were set aside in the embryo and prevented from differentiating. They are referred to as embryonic germ cells because they were destined to give rise to the eggs or sperm of the next generation.
ES and EG cells have two remarkable properties. First, the cells are in principle immortal. Whereas most cells divide a finite number of times and perish, ES and EG cells can be cultured to divide indefinitely, which makes them excellent objects for manipulation by researchers. Second, they are pluripotent; that is, they can turn into many cell types. All other cells have to some degree differentiated; that is, they have turned into one or another type of cell, such as nerve or muscle or skin. No one has yet successfully directed ES and EG cell differentiation to an extent that would be clinically useful, but the hope is that someday soon these cells will be used to generate specific, transplantable tissues.
Despite the potential for medical benefit offered by ES and EG cells, the origin of these cells raises policy and ethical concerns. In the United States the policy issues primarily concern the use of federal funds for research involving human embryos and fetal tissue. The ethical concerns are primarily related to the moral status of the embryo and the aborted fetus.
Human fetal tissue has been used in research aimed at developing therapies for disorders such as Parkinson's disease by transplanting that tissue into afflicted people. Before 1993, laws in the United States prohibited the use of federal funds for this research because the tissue used is obtained from aborted fetuses. In 1993 Pres. Bill Clinton lifted that ban. A number of restrictions exist to ensure that fetal tissue for research is obtained in a manner that respects the women from whom it is taken and that research does not encourage abortion. These restrictions are likely to apply to EG cell research.
First, the physician is required to obtain the woman's informed consent to
use fetal tissue removed from her body. Second, to ensure that the possibility
of donating tissue to benefit medical science does not influence a woman's decision,
the donation of fetal tissue can be discussed only following a decision to terminate
the pregnancy. Finally, a woman may not direct that her fetal tissue be used
to benefit a particular person.
The policy situation with respect to human embryonic stem cells is more complicated. Currently, U.S. law prohibits federal funding of human embryo research. Consequently, private corporations have taken the lead and funded the research mentioned above that isolated the first human ES and EG cells. Lawyers for the U.S. National Institutes of Health, Bethesda, Md., have provided a legal opinion that states that under the current law it is legal to fund research on human ES cells so long as federal funds are not used to support the derivation of those cells. Although this legal interpretation may be technically sound, it places the U.S. government in the paradoxical position of withholding funds from research to derive ES cells but permitting funds for research on ES cells once they have been derived by means of private funds.
The ethical problems associated with ES cells are largely connected to the question of the moral status of the embryo. How one evaluates the act of deriving ES cells depends on whether one believes the human embryo is a person, a mass of human cells, or something in between that requires special consideration. Science cannot answer this question. Currently, most Western countries permit embryo research for specific purposes and within certain strict limits. They proceed from the view that embryos have neither the moral status of persons or that of mere cells; because of their special connection with the human community, they enjoy an intermediate position that requires that they be treated with special respect. The National Bioethics Advisory Commission (NBAC) has debated the ethics of ES and EG research and recommended a partial lifting of the embryo research ban so that research using surplus embryos can be eligible for federal funding.
Many people argue that creating embryos for research does not recognize the special status of the human embryo. Some argue that there is no important moral difference between doing research on embryos originally created for reproduction and doing research on embryos specifically created for that purpose. NBAC decided, however, to recommend that funding be available only for research on surplus embryos.
Finally, ES cell research implicates the cloning debate. Many countries have policies forbidding the use of cloning, or somatic cell nuclear transfer (SCNT), to create a human being (reproductive cloning). It is possible, however, to use SCNT to create embryos as a source of ES cells. A patient can donate a tissue, and by means of SCNT it is possible to create a source of ES cells with that patient's DNA. Consequently, this therapeutic cloning technique offers the potential to create tissues for transplantation that exactly match the recipient's tissues.
ES and EG cell research offers the potential of great medical benefit, but
it also raises difficult ethical issues and complicates policy development.
This turbulent area of research will surely command our attention well into
the next millennium.
Lori P. Knowles is Associate for Law and Bioethics and Erik Parens is Associate for Philosophical Studies at the Hastings Center, Garrison, N.Y.
Copyright © 1994-2001 Encyclopædia Britannica, Inc.
Scientific American Perspectives as given by the Editors. In the May 2001 issue of the Scientific American the following has been stated under the title: Save Embryonic Stem Cell Research.
We know that embryonic stem cells can differentiate into any tissue of the of the human body; might they therefore also be able to treat diseases like Parkinsons, Alzheimers and diabetes? In principle, this ability to differentiate into blood, muscle or neural tissue may make embryonic stem cells the gold standard for replacing bad tissue with good. But some antiabortion advocates, rankled that these cellular chameleons come from embryos, call for a categorical ban on funding this research.
In 1996 Congress forbade the use of federal funds for research that would involve destroying human embryos. Last year, however, the National Institutes of Health issued guidelines, supported by the Clinton administration, that would allow embryonic stem cell research to continue as long as the harvesting step was not conducted with federal monies. In vitro fertilization clinics have been a source of the cells because such clinics regularly discard frozen embryos left over after conception attempts.
Opponents insist that the NIH is dodging its moral responsibility by letting private clinics do the dirty work. And the Bush administration may be swayed by this argument as it decides whether to overturn the NIH guidelines. Health and Human Services Secretary Tommy Thompson has said that a recommendation on the issue will be announced by late spring or early summer. Eighty Nobel laureates and a variety of research institutions have petitioned the president not to stand in the way of the research. They maintain that a ban will hinder all progress on the stem cells and that the U.S. in particular would stand to lose competitiveness in biotech.
Polls have suggested that most of the American public, too, thinks that embryonic
cell research should continue, which means that the government must decide how
to balance ethical objections from a minority against the wishes of the majority.
It would be a mistake to think that that the pro-life side has undisputed claim
to the moral high ground. Many people question whether it is right to ignore
research that offers the best hope for treating or curing so many cruel illnesses.
Opponents of the research might retort, Why not continue using only adult stem cells? Some stem cells can be found in adult tissue as well, after all. The scientific answers that we dont yet know whether the adult cells necessarily retain the full plasticity of the embryonic ones. Research should and will continue on the adult stem cells, and if they ultimately prove as capable or better than embryonic ones, it might then be wise to forsake the embryonic cells in deference to the moral debate over whether an embryo is really a human being. Until then, however, adult stem cell work can only be an adjunct to the embryonic work.
No one should too readily dismiss the objections that using embryos in this
way is an insult to human dignity. But these were embryos already abandoned
by their parents as by-products of other conception attempts. Currently these
embryos have exactly zero chance of ever maturing into human beings. Stem cell
research offers the cells more opportunity for life than they would otherwise
see. It offers many afflicted people an opportunity for healthier, longer lives.
Saving embryonic stem cell research may not be an easy choice, but it is the
right and moral one.
Catholic Perspectives as presented in America, the National Catholic Weekly, September 17, 2001, under the title Ethics Notebook: Stem Cell Challenges by John Kavanaugh S.J. Here is a partial presentation of the text.
Most cells of any animal could, with the help of special chemical procedures, develop into a genetic replica of the whole animal. Thus, in the famous case of Dolly, the nucleus of one cell from an adult lambs udder was injected into another sheeps reproductive cell (with its own nucleus removed from the membrane and the cytoplasm) and prompted to replicate on its own. At the earliest stages of development, the cells of this new embryo, like cells in embryos conventionally conceived, are pluri-potent. They are called stem cells because they have the potency to develop into multiple kinds of tissue and organs, which in fact, they do as the embryo develops. That very development restricts and channels the cells, as if they somehow forget how to make a whole organism and start forming differentiated neural, heart, liver or skin tissue. Thus, embryonic stem cells are powerful instruments not only for research, but possibly for curing neural, heart and liver diseases.
It has become clear, however, that not all our specialized or adult cells forget their pluri-potential possibilities. Muscle, brain and blood therapies have been developed from umbilical cord blood, placentas and adult stem cells in bone marrow, brain and fat tissue. In these procedures there is no embryo involved whether left over from reproductive clinics, or created in a cloning process. There is also no problem of immunity rejection, since the cells are donated by the patient rather than an unknown embryo.
But this suggests another option. In order to prevent immune rejection in embryonic stem cells, some scientists propose that the best therapy would be to create an embryo from the genetic clone of the patient. If I have liver disease, for example, why not use a nuclear transfer by injecting the nucleus of one of my cells into the cytoplasm of a denucleated donor ovum, create an embryonic clone, and then harvest its stem cells?
This procedure is now being done, not with government funds, but by the questionable gift of the free market and the belief that there should be no restraints on what we can or want to do. Advanced Cell Technology Inc., of Worcester, Mass., has been paying women donors for eggs to be used in therapeutic cloning. The company president claims that they are not trying to clone people. It is more accurate to say that at this time, they are not planning to bring any cloned human embryo to term.
Is this something like creating a human in order to destroy it? It is. The
only reason any embryonic stem cell is of interest to science is that it is
human and it is alive. The whole present debate is belying, once again, the
feeble claim that we do not know when a living human being begins. We know when
it begins. That is why we have been tempted to become its primary predators.
For this reason, while favoring research on adult stem cells, I oppose any discarding of extra embryos or creating them to cannibalize them.
For more information of the ethical evaluation of stem cell research and human cloning see the section on Ethical Considerations.
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