Stem cell research
AuthorDr Abboud is a medical doctor and bioethicist who teaches at the University of New South Wales, in Sydney. He is also director of Australasian Bioethics Information, a clearinghouse for news about ethical practice in medicine and medical research.
Why the controversy?The average person is baffled by the stem cell debate. Blastocysts, morulae, mitochondria, cytoplasm and dozens of other words are terms that they never even learned properly in high school biology. But you don’t need to be a biologist to understand the importance of the ethical controversy which has put stem cells on the front pages of newspapers around the world.
The fundamental issue is the limits of regenerative medicine. This is an exciting new field with enormous potential for repairing damaged organs and body parts with human stem cells. Vast amounts of money and research effort are being invested in it. But like every technological development, it is not ethically neutral. We have to ask where these stem cells will come from. If their source is human embryos, there is a serious ethical difficulty. The destruction of embryos for the sake of stem cells is ethically unacceptable. Human life, even embryonic human life, cannot be sacrificed as a research tool or a medicine.
A brief introduction to stem cellsNormally a skin cell remains as a skin cell all its life. A nerve cell remains as a nerve cell until it dies and so on. Stem cells, however, are cells that can change into other types of cells, such as heart cells, nerve cells, muscle cells, skin cells and so on. They are the trunk or the major branches from which smaller branches (different cell types) develop. The ultimate stem cell are the stem cells in the early embryo because they can develop into every single cell type.
Stem cell science is very new and scientists are constantly rewriting the textbooks. At the moment, public discussion is focused on two kinds of stem cells: adult stem cells and embryonic stem cells. Adult stem cells can be taken from body tissue without harming a patient. The word "adult" means only that the cell has been taken from a fully developed organism. This could be an adult, a child, or even from the placenta of a newly-born infant. Embryonic stem cells are removed from early embryos in a process which destroys the embryo. Another type of stem cell is the embryonic germ cell, or foetal stem cell, which is taken from aborted foetuses. These are believed to have almost the same potential as embryonic stem cells.
This backgrounder focuses on the ethics of using embryonic stem cells. Although there are ethical issues with the use of adult stem cells, as with any medical treatment, the use of embryonic stem cells is inherently problematic because it always involves the destruction of an embryo.
The potential benefits of stem cell treatmentIt is important to understand why scientists are so excited by the potential of stem cell research. You can think of stem cell therapy as a kind of microscopic organ transplant. When injected into the body, the cells will travel to damaged tissue and replace or repair it. Currently there are many degenerative diseases which cannot be treated effectively. Stem cell therapies, scientists say, could possibly cure patients with Parkinson’s disease, diabetes, spinal cord injuries, heart disease and cancer.
But these developments are a long way off. Even boosters of embryonic stem cell research have conceded that stem cell therapies may be decades away. Diseases are always complex and cures are never simple. Enthusiastic chatter about the theoretical possibility of cures often glosses over years of work in the laboratory to create a therapy which is workable, safe and cost-effective. Optimism must always be tempered with realism.
It is important to stress that the only stem cells that have helped patients so far are adult stem cells. Embryonic stem cell research has not helped a single patient in the entire world. Up til now, it has a zero success rate.
Obtaining stem cells from embryosHuman embryos are not easy to obtain. At the present time, there are basically three sources: embryos which are left over from IVF treatment, embryos which are created in the laboratory from donor eggs and sperm, or embryos which are cloned from somatic (body) cells.
The embryo is allowed to grow for about five to seven days after fertilization and then it is divided into its component parts. Of course, the embryo is killed in the process. The stem cells are placed in cultures where they multiply rapidly into colonies, or clusters, of cells. The next step is to coax them into becoming the desired cell type (e.g., heart cells, pancreatic cells, brain cells). Programming the cell to differentiate is the focus of intense effort by many researchers around the world. Up to now they have had very limited success.
Some stem cell scientists regard frozen IVF embryos or embryos made from donated eggs and sperm as a useful research tool for investigating the mysteries of embryo development and the mechanisms of genetic diseases. But, at this stage, it is highly unlikely that they can be used for cures. The problem is that the stem cells from these embryos will not have the same genetic make-up as the patients and will be rejected without using anti-rejection drugs.
So the preferred option, in the view of many scientists, is to create new embryos, via nuclear somatic transfer. This is the same method used to clone Dolly the sheep. That is, human embryos would be deliberately created for the sole purpose of extracting their stem cells, a procedure often billed as “therapeutic cloning”. This is a great misnomer as it is not therapeutic for the embryo. Some scientists and biotechnology investor predict that cloing embryos will usher in the age of “personalized medicine” -- treatments which are tailor-made for individual patients. This implies, of course, that scientists will be allowed to create “embryo farms” on an industrial scale.
Therapeutic cloning also involves another serious ethical problem. The availability of human eggs limits its potential. Eggs are scarce and expensive because few women are willing to experience the pain, inconvenience and physical risk involved in harvesting eggs. If a market develops for eggs, poor women are sure to be exploited -- which is one reason why a number of feminists oppose “therapeutic” cloning. Therefore, in an escalation of the moral complications associated with stem cell research, some researchers have suggested the possibility of creating hybrid cow-human or rabbit-human embryos with animal eggs.
Adult stem cells and regenerative medicineThe only stem cells which have worked in a clinical setting are adult stem cells. In fact, adult stem cells have been used for about 30 years in procedures like bone marrow transplants. In the last few years, scientists have also discovered that adult stem cells exist in many parts of our own body -- the brain, bone marrow, skin and fat and many other locations. The use of these cells has had an impressive head start, although no therapies have yet passed all the hurdles to become a standard clinical treatment.
It used to be thought that embryonic stem cells had more clinical potential than adult stem cells because they are easier to identify, isolate and harvest; because they are easier to obtain; because they grow more quickly and easily in a laboratory setting; and because they are more “plastic”.
Yet all these arguments have proved false. The first two claims are misleading. The challenge of identifying and isolating adult stem cells is being overcome. Several biotech companies have developed proprietary methods to make adult cell isolation and extraction even easier. Although every kind of adult stem cell is present distinct problems, researchers have identified conditions that would allow the multiplication of some kinds by a billion-fold in a few weeks.
The key argument for using stem cells from embryos is they are more ”plastic” — that is, they are easier to change into other types of cells. While this claim has some basis the technology is improving so rapidly that it would be rash for anyone to say that adult stem cells will not become a source of all types of somatic cells. The US National Institutes of Health has observed that “the field of stem-cell biology is advancing at an incredible pace with new discoveries being reported in the scientific literature on a weekly basis.”
While adult stem cells may never be as completely “plastic” as embryo stem cells they will almost certainly be plastic enough for all practical applications. “These adult tissues don’t appear to be as restricted in their fate as we thought they were,” said Dennis Steindler, a professor of neuroscience and neurosurgery at the University of Tennessee-Memphis. “In some ways they may not have the same potential as embryonic cells, but once we figure out their molecular genetics, we should be able to coax them into becoming almost anything we want them to be.”
Furthermore, some researchers are doing promising work on adult stem cells which appear to share with embryonic stem cells the ability to morph into any type of tissue. Three scientists have recently published peer-reviewed work which indicates that some kinds of adult stem cells may be as malleable as ESCs. Catherine Verfaillie, of the University of Minnesota, is investigating rare bone marrow stem cells; Alan Mackay-Sim, of Griffith University in Brisbane, is looking at nerve cells in the nose; and Douglas Losardo, of Tufts University, has found that bone marrow differentiated into nine kinds of tissue. Amazing as it may seem to the non-scientist, the anatomy of the human body still has not been fully categorized at a cellular level; there may be other cells which can differentiate into many kinds of tissue.
Media hype suggests that there is no alternative to embryonic stem cell research. But this is a deception propagated by those with a personal and financial interest in the benefits of destructive embryo research. No one has a right to destroy embryos to do this research. We should push ahead with successful and ethical adult stem cell research which involves no destruction of embryos -- and works.
Stem cells and cloningEmbryonic stem cell research is the threshold of cloning. As we have already seen, to overcome the problem of immune rejection, the proponents of embryonic stem cell therapies will have to clone embryos. Although nearly all scientists have vowed not to allow these cloned embryos to develop into babies, they certainly could if they were implanted in a womb. Several rogue researchers have already attempted to do this.
Furthermore, nearly all scientists who want to work with embryonic stem cells do not appear to have ethical qualms about so-called reproductive cloning. They simply say that it is unsafe for the cloned child. In its ethical guidelines for stem cell research, the US National Academies of Sciences says (May 2005) merely that “attempts to create a child by means of NT [nuclear transfer, or cloning] are ethically objectionable at this time because, on the basis of experience with other mammalian species, producing one child might require hundreds of pregnancies and many abnormal late-term fetuses could be produced”.
At the present time, this is undoubtedly true. But veterinary scientists are working hard to overcome these problems and eventually their research will be applied successfully to the problem of human cloning. When that happens the gossamer-thin ethical objections of stem cell scientists will evaporate. Unless we can put a stop to embryo cloning, the cloning of children is all but certain. The only “bright line” separating therapeutic cloning from reproductive cloning is the intention of the laboratory which creates the embryos. Already a few American couples have publicly appealed to clone their dead children. American lawyers have speculated that if there is a constitutional right to reproduction, there must be a constitutional right to the means to reproduce, even if this means cloning.
The ethics of stem cell scienceThe debate over embryo research is not a specifically religious issue. First and foremost it is a human rights debate and a debate about good science versus bad science. In this case, the science which respect human rights has notched up all the successes. Religion sheds light on the stem cell debate by highlighting the importance and scope of human dignity as revealed in the Bible or the Koran. But one does not need to be a believer to see that manipulating and destroying human embryos involves serious ethical issues. Because embryos are an early form of human life, the principles which govern how they are treated will be applied to other stages of human existence. But the fundamental parameters of the debate are set by what constitutes competent ethical science which respects human rights.
The debate over embryonic stem cells is fierce and emotional. But it is important to stress the following points:
- It is unethical to destroy a human embryo. The destruction of innocent human life can never be justified, even if the aim is to save another human life. It is often argued that embryos are too small to be human and can therefore be used as research material. But size is no guide to the nature of things. If the Big Bang theory is to be believed, the entire universe was once smaller than the period at the end of this sentence -- yet it contained literally everything. Similarly, embryos are said to lack humanity because they cannot survive outside of the womb. True enough, but the world's most famous physicist, Stephen Hawking, is confined to a wheelchair and cannot even speak because he suffers from Lou Gehrig's disease. He is utterly dependent upon his carers -- but no one questions his humanity.
- Embryonic stem cells can cause cancer. They certainly are very “plastic”, but the flip side of plasticity is a predisposition to become malignant. This is a real concern even for supporters of embryo research. The editor of the journal Stem Cells in September 2001 made the following startling admission “I continue to think that clinical application is a long way off. Prior to clinical use of embryonic and foetal stem cells, it will be necessary to thoroughly investigate the malignant potential of embryonic stem cells.” Adult stem cells seem to be more stable than embryonic stem cells and are not as prone to the formation of tumours.
- It is unnecessary to use embryos. Adult stem cells are proving to be a viable alternative. For example umbilical-cord blood and placenta blood are both rich in stem cells. Scientists have found stem cells in adults in virtually every major organ, including the brain. And as we have seen, they have already been successfully used in treatment, while embryonic stem cells still offer only theoretical potential for good. This point is worth emphasising: While many actual benefits have been obtained from adult stem cells over recent years, we have as yet no demonstrated benefit to human patients from embryonic stem cells.
- The benefits of embryonic stem cell research are a long way off. Although media hype -- sometimes fed by publicity-hungry scientists -- often hints that cures for dread diseases are only five to ten years away, this is very doubtful. It is criminal to give the sick false hope about the imminence of cures.
- In fact, because therapies are so distant, supporters of the use of embryonic stem cells began to shift their arguments after the 2004 US election. Nowadays they are very cautious to emphasis the dangers of false hope. However, they now stress that these cells will be very useful for research into the genetic basis of disease and for drug testing. Pharmaceutical companies need to know whether new products could harm patients and how their drugs actually work. Because animal liberation activists are making it very difficult to conduct animal experiments, researchers can use embryos instead. Humans are cheaper and less controversial than lab animals. In other words, the fate of embryos used in research is less likely to be curing the sick than enriching entrepreneurial scientists and big drug companies.
- By using adult stem cells we overcome the problem of immune rejection, which will be a big problem with the use of embryonic stem cells. Our bodies quickly recognise and try to kill off foreign tissues implanted in them. By using cells from your own body, the compatibility problem is avoided.
Embryo research and human dignityResearch on embryos is research on embryonic persons. It denies the dignity of the human embryo. The human embryo is a distinct, living human being, and is entitled to all the rights and protections as any other human being. Human life begins at conception (or fertilisation). Therefore, the human embryo (regardless of what means by which it is created) should not be treated as a means to an end. It is entitled to life and respect. Once embryonic development commences, a separate and distinct human being exists whoshould not be used in a purely instrumental fashion. For this reason any technology or proposed therapeutic procedure which involves the destruction of a human embryo should be banned altogether.
Those who argue that a frozen IVF embryo would be destroyed anyway miss the point. The couples who had the embryos created did so for the purpose of implantation, of bringing about life. That surplus embryos exist should be a real concern. It is a scientific mess created by the IVF process. But we should not add to the mess by experimenting on the embryos. We need to find more humane solutions to the ethical dilemma of surplus IVF embryos. Adoption is one possibility. If this is not an option then they can be allowed to die with dignity.
Experimenting upon embryos denies them their fundamental right to be treated with dignity. This can be a hard point to grasp, but an historical example might help to clarify the issues. Not long ago in Austria body parts of hundreds of babies and children were discovered in the office of a famous doctor. He had obtained them during the Nazi period of 1940 to 1944 and used them in his research. When this came to light Austrians were outraged. The authorities did not argue that the children were dead anyway and that valuable knowledge could be obtained from their vital organs. A public interment was attended by huge crowds of mourners. The situation with defenceless embryos is analogous.
Internet resourcesWhat We Know About Embryonic Stem Cells
by Maureen L. Condic. First Things. January 2007
The Many Casualties of Cloning
by Richard M. Doerflinger. The New Atlantis. Spring 2006.
by Robert George and Eric Cohen. National Review Online. Mar 20, 2006
To clone or not to clone
interview with James Sherley, MercatorNet, December 6, 2005
A Distinct Human Organism
by Robert P. George, NPR.org, November 22, 2005
Alternative Sources of Pluripotent Stem Cells
by the President's Council on Bioethics. May 2005
A discussion of alternatives to using stem cells from human embryos.
Monitoring stem cell research
by the President's Council on Bioethics, January 2004
An exceptionally thorough and objective examination of the state of stem cell research by a council headed by Dr Leon Kass.
The Shady Side of Embryonic Stem Cell Therapy
by Stephen Barrett, M.D.
A lurid expose of rogue scientists in Eastern Europe and the Carribean who "cure" patients with embryonic stem cells. Quackwatch, March 2004
Quick Scientific References: Human Cloning, Human Embryonic Stem Cell Research
by Dianne N. Irving
An thoroughly documented article with citations from current literature arguing that "the immediate product of sexual (fertilization) reproduction is a new living single-cell human being".
Human Embryonic Stem Cells and Cloning: Science and Bioethics at a Crossroads
by Martin Clynes
A thoughtful article by an Irish biotechnologist on the ethics of embryo research
Stop the cloning madness
by Dr. James L. Sherley, Boston Globe, 20 October 2004
A powerful argument against therapeutic cloning by an MIT biotechnology researcher
WebsitesDo No Harm: The Coalition of Americans for Research Ethics
An excellent compilation of recent stem cell news and op-ed articles from newspapers and magazines
Stem Cells in the Spotlight, Public Agenda Alert, 14 October 2004
Taking the pulse of public opinion: polls show woeful ignorance of the issues involved in embryo research
Articles by MercatorNet contributorsParliament's last chance to preserve human dignity
by Michael Cook, Australian, December 22, 2005
‘We Have to Formulate Our Own Bioethics’
by Michael Cook, TCS Daily, 2 December 2005
Eggs Over Easy? False Dawn for Stem Cell Cures
by Michael Cook, TechCentralStation, 25 May 2005
Ethics as our guide
by Michael Cook, PLoS Biology, June 2004
"Blackburn and Rowley's criticism of a report on embryonic stem cell research from the President's Council on Bioethics is puzzling. Where is the bioethics?..."
Has experimenting on human life lost its power to disgust?
by Michael Cook, The Age (Melbourne), 19 August 2003
"It's taken less than two years for us to get used to regarding human embryos as pharmaceutical fodder."
Useful quotes“In medical research on human subjects, considerations related to the well-being of the human subject should take precedence over the interests of science and society.” ~ Helsinki Declaration of the World Medical Association (1964 and subsequent ratifications)
"No community, whether family, village or state, is really strong if it will not carry its weak and even its very weakest members. They belong to it no less than the strong, and the quiet work of their maintenance and care, which might seem useless on a superficial view, is perhaps far more effective than common labour, culture, or historical conflict in knitting it closely and securely together." ~
Evangelical Theology: An Introduction
“I think ESCs [embryonic stem cells] are going to fade into the rearview mirror of ASCs [adult stem cells]” --
Dr Douglas Losardo of Tufts University,
"Marrow Has Cells Like Stem Cells, Tests Show".
Washington Post, 2 Feb 2005.
“All grown-ups were once children – although few of them remember it”
-- Antoine de Saint-Exupéry
“Adult stem cell research is predicted to beat the pants off human therapeutic cloning research when it comes to yielding significant advances in cell medicine. And adult stem cells provide better approaches. These cells that naturally function in the regeneration and repair of adult tissues pose no ethical concerns.”
James L. Sherley, biotechnology lecturer at MIT
"Stop the Cloning Madness"
Boston Globe, 20 October 2004
"I am opposed [to the use of embryonic stem cells] but not only for ethical reasons. Mother Nature made embryonic stem cells to proliferate and adult stem cells to replace and repair. To defy Mother Nature's laws is, at least, dangerous."
Carlos Lima, expert on spinal cord regeneration
"New hope for paralysed woman"
London Telegraph, 6 December 2004
“The ethics of stem cell research is sometimes seen as a religious issue, but I see it primarily as a human rights issue based on an analysis of the biological facts. The only single definitive transition point, from a scientific perspective, in the formation of a new human individual person, is when the DNA from mother and father come together within the fertilised egg... There is no other stage or event in development which we could pick and with any confidence say "no person existed before this point". But why is all this so important? Well, throughout history, whenever any group has been labelled subhuman, serious abuse has followed. Our current use of language like "spare" and "supernumerary" to describe embryos may conveniently hide the reality of a real personal existence and encourage us to think of these beings as mere commodities. In the past, people were dehumanised by labels of colour, race, gender, class, caste, and religion - maybe this generation's error is characterisation by stage of development.”
Dr Martin Clynes, professor of biotechnology at Dublin City University
"Human Embryonic Stem Cells and Cloning: Science and Bioethics at a Crossroads".
Studies (Ireland), 2004.
If by a combination of philosophical and empirical reasoning, then, it can be shown that the foetus really is a young human being, we will have shown that it is a human being pure and simple… It will not look like a mature member of its kind, to be sure – because it isn’t mature. But it will certainly look like an immature member of its kind, if that is what it in fact is."
If by a combination of philosophical and empirical reasoning, then, it can be shown that the foetus really is a young human being, we will have shown that it is a human being pure and simple… It will not look like a mature member of its kind, to be sure – because it isn’t mature. But it will certainly look like an immature member of its kind, if that is what it in fact is." David S. Oderberg.
Applied Ethics. Blackwell: London, 2000, pp 5 – 6.
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