Stem Cell Research And Cloning Controversy Essay
By John Pickrell
Fast-forward to the end of the 21st Century: surgeons can create new organs to order, regrow crippled spines and hearts and reverse the damage of Parkinson’s disease or diabetes with ease. Immune rejection and waiting lists for replacement organs are consigned to history.
Stem cells may have the potential to fulfil this promise and much more, but there are still many technical, ethical and political obstacles to overcome before real therapies are possible.
Doctors have been transplanting adult blood stem cells, in the form of bone marrow transplants, for many decades, but stem cells from human embryos were only isolated and cultured in 1998. Though research has progressed rapidly since then, we still have much to understand; not least what gives stem cells their unique properties, but also how exactly they are able to differentiate into the 300 or so different types of human cell.
Despite their medical promise, stem cells have been dogged by political and ethical controversy because some are derived from discarded human embryos, and because of fears and confusion about links with human reproductive cloning. The future of stem cell therapies was thrown deeper into doubt in late 2005, when a leader of the field – Woo Suk Hwang, South Korea’s “stem cell king” – was found to have forged key discoveries and flouted ethical protocols. So has the stem cell miracle been postponed?
Full of potential
Embryonic stem cells (ESCs) come from fertilised human embryos – pinhead-sized balls of cells called blastocysts – just a few days old. In the embryo, these cells go on to form all the tissues of the developing body. They have generated so much interest because they are virtually immortal in the laboratory and can also generate any tissue type from bones to brain cells – making them pluripotent.
So far, most existing ESC colonies come from human embryos leftover from infertility treatments. But women are now donating eggs specifically for stem cell research in some countries.
The cells could potentially be cultured in the lab as an unlimited source of repair tissue for many ailments. Humans might even one day regenerate missing parts, as newts do.
Besides regeneration, stem cells could also be studied to provide insights into how human bodies develop from fertilised eggs. Stem cells with genetic defects could further be used to understand how congenital diseases, such as cystic fibrosis, develop. Stem cells might also be used to test new drugs in the lab on a range of tissues, instead of on people or animals.
Adult stem cells
As well as the fetus, stem cells are also found in the placenta, amniotic fluid and umbilical cord, and they remain in many adult tissues. Cord blood is sometimes collected at birth today, and the stem cells stored.
Adult stem cells have been found in: bone marrow, blood, the cornea and retina, intestine, liver, muscles, nervous system and the brain, pancreas and skin. These “multipotent” stem cells are less flexible than ESCs and are typically only able to form cells of the tissue in which they reside. “Adult” distinguishes these cells from their embryonic equivalents, but they are present in children too.
For example, hematopoietic stem cells are blood-forming stem cells, which largely reside in bone marrow. They are responsible for replenishing all blood cell types on a continual basis. It is these stem cells that rebuild the damaged blood system of leukaemia sufferers after successful bone marrow transplants. MesenchymaL stem cells, also found in bone marrow, can go on to form cells including muscle, fat, skin and cartilage.
Though adult stem cells are less flexible than ESCs, and are not immortal in the laboratory, they sidestep the ethical quandary of destroying embryos. Furthermore, we may be able to stimulate the adult stem cells we already possess to travel to and repair damaged tissues within our bodies.
Currently stem cells of both types are being tested to treat many conditions, including: Alzheimer’s disease, blood disorders, blood loss, baldness, blindness, cystic fibrosis, deafness, diabetes, heart disease, kidney failure, liver damage, lupus, motor neuron disease, multiple sclerosis, osteoporosis, Parkinson’s disease, spinal cord injuries and stroke.
Stem cells have also been used to fight cancer, treat dogs and race horses, and provide tissue for human breast implants and replacement teeth.
Researchers still have much to learn about how to direct stem cells to form and repair different tissues and how they behave within a patient’s body. Even identifying stem cells is difficult currently. Concern that stem cells could divide uncontrollably to form tumours called teratocarcinomas is also likely to delay major clinical trials for some years. Stem cells might also become cancerous in the lab.
The cloning connection
The most significant hurdle however, is immune rejection. As with any tissue transplant (from a donor other than an identical twin), the body will recognise ESCs as foreign and mount an attack which could destroy them. ESC recipients would have to take immune suppressant drugs for the rest of their lives.
Multiplying a patient’s own adult stem cells in the lab and then reinjecting them is one way to avoid rejection. Duping the immune system is another possibility, perhaps using stem cells from the brain that somehow avoid detection.
Therapeutic cloning is a clever technique that circumvents the problem. We can make custom-made ESCs using a patient’s own DNA and a donor egg. In the same way as reproductive cloning, the nucleus of a skin or muscle cell from the patient is added to an unfertilised egg that has had its own genetic material removed. This egg is then persuaded to divide as though it had been fertilised and, with luck, goes on to form the ball of cells called a blastocyst. At this point, the inner cell mass is removed and cultured in the lab to derive stem cells. These stem cells now contain the DNA of the recipient and would not be treated as foreign by the immune system.
But, in theory, the cloned embryo could be implanted into a womb where it might develop into a cloned human baby. This would be reproductive cloning, and is the same method used to produce Dolly the sheep.
Producing viable clones of many species is a lengthy and difficult problem, and has yet to be proven in humans – despite questionable claims of success.
In any case, reproductive cloning has been banned in many countries for ethical reasons and because of suspected health risks to the clone. It was banned in the UK in 2001. Despite strong opposition, it has yet to be banned in the US.
For many, the destruction of embryos for scientific purposes is unacceptable, so numerous countries – such as Germany and France – also support bans on therapeutic cloning and using embryos to derive stem cells. A total of 87 nations voted for a resolution totally banning both types of human cloning in March 2005, but it was abandoned due to failure to agree on therapeutic cloning.
For others, the medical benefits outweigh these concerns. For example, in the UK, Belgium, Sweden, Japan, China and South Korea, therapeutic cloning has been allowed, but regulated. In the UK, licenses have been granted for studies into diabetes and motor neuron disease. ESC lines have been created in the UK since 2003. The EU provides some funding for ESC research in those countries that have embraced it.
In the US, the situation has become complicated. Disagreement between the religious groups who want a total ban on cloning and an equally vociferous pro-therapeutic cloning lobby has stalled legislation. In the place of a ban, US president George W Bush introduced legislation that restricted federally funded research to 22 stem cell lines created before 2001. However, research now suggests that these lines may have been tainted with material from mousefeeder cells in the lab, rendering them useless for human therapy. New ESC colonies free of this contamination have now been created.
Some US states have taken the situation into their own hands. California agreed a plan in 2004 to provide $3 billion for stem cell research over 10 years. By contrast, the Bush administration has pledged just $25 million annually to stem cell research.
In response to these restrictions, the race is on to find an ethical stem cell source – one that does not involve destroying embryos. One method does exist, but it creates ESCs with abnormal chromosomes. Other methods extract stem cells without destroying embryos, or create embryos that could never become babies. Further possible sources are: baby teeth cells, “universal” adult stem cells umbilical cord blood and testicle cells.
Fall from grace
Politics is not the only controversy that has gripped the stem cell world.
In May 2005, one of the world’s top stem cell scientists – South Korea’s Woo Suk Hwang – announced that his team had used therapeutic cloning to produce 11 ESC lines tailored to individual patients. This was one of a string of remarkable achievements. In 2004 Hwang cloned human embryos for the first time, and he later produced the world’s first cloned dog – an Afghan hound named Snuppy.
Then in late 2005, the research community was rocked by claims that Hwang had flouted ethical guidelines by obtaining eggs from women in his own research group. As investigations proceeded and other transgressions unfolded, it became clear that much of his research had been fabricated. There are now questions over his use of funds too.
The fall from grace has been spectacular for a man who was revered as a national hero in South Korea, and the repercussions have travelled far and wide. Collaborating researchers have been tarnished by association, other stem cell science is in doubt, investors are wary of stem cell medicine, and there are now questions about how easy it is to fabricate results.
The already controversial field of stem cell research was brought further into disrepute, and it remains to be seen how much the scandal will delay the development of the miracle therapies that are so desperately desired.
More on these topics:
What if I told you that researchers could cure diseases such as Parkinson's disease and multiple sclerosis? Odds are, you would be in favor of ending the suffering of the thousands of people who currently battle such diseases. These cures and many more are the potential results of embryonic stem cell research. Embryonic stem cells are stem cells isolated from embryos during a specific stage of development known as the blastocyst stage. These stem cells can renew themselves and reproduce to form all cell types of the body. Research utilizing these stem cells requires the destruction of an embryo, making the practice a point of moral, scientific, religious, and political controversy. Many argue that the destruction of embryos for research purposes is unethical based on the belief that embryos qualify as forms of life that deserve respect. Those in favor of embryonic stem cell research deem such a loss acceptable for the future benefits that this research could have on thousands of lives. While various arguments surround this debate, the main point of controversy is the source of stem cells used and the method with which they are obtained. In this paper, I will establish what stem cells are and the difference between embryonic and adult stem cells; then I will evaluate the two main arguments in the embryonic stem cell research debate; and finally, I will analyze the ethics of these arguments to come to the conclusion that embryonic stem cell research is ethical under certain circumstances.
Overview of Stem Cell Research
As defined by "The Human Embryonic Stem Cell Debate: Science, Ethics, and Public Policy," human embryonic stem cells are "a self-renewing cell line that gives rise to all cells and tissues of the body" (Holland 3). Most stem cells are only able to differentiate into a single form of offspring cells, otherwise known as progeny cells. For example, hematopoietic stem cells are a type of stem cells that can only form blood cells and skin stem cells can similarly only produce skin cells. These types of stem cells are referred to as adult stem cells or somatic stem cells because they are gathered from patients after birth (Devolder 5). Meanwhile, embryonic stem cells are pluripotent, meaning they have the capacity to produce all cells and tissues of the body (Holland 5). Embryonic stem cells, however, only have this pluripotent potential for the particular five-to-seven-day stage of embryonic development known as the blastocyst stage, after which they can only reproduce a single cell type ("The Ethics of Embryonic Stem Cell Research" 123).
Stem cells, in general, hold great promise for the future of medicine. Thus far, stem cell-based therapies have been developed to treat illnesses that previously had no cure. One example is bone marrow transplantation to treat leukemia and other blood disorders. The hematopoietic stem cells in bone marrow are injected into a patient who has severely reduced blood cell levels and these stem cells generate new blood cells, restoring the patient's immune system (Devolder 5). Therapies such as this will continue to be discovered with the support of stem cell research.
In addition to the development of revolutionary therapies, stem cell research also provides valuable information about mechanisms regulating cell growth, migration, and differentiation. Scientists can learn about these processes by studying stem cells that have been stimulated to differentiate into different types of body cells. The discovery of new information about these concepts will allow scientists to better understand early human development and how tissues are maintained throughout life (8).
Embryonic stem cells are particularly valuable not only because of their pluripotent qualities, but also because of their ability to renew themselves. This is done by "divid[ing] asynchronously – at different times – into one differentiated daughter cell1 and one stem cell-like daughter cell." This unique self-renewing quality of embryonic stem cells allows them to continuously grow even in laboratory conditions. Other types of stem cells eventually lose the ability to divide, making them less valuable for research purposes. Embryonic stem cells' ability to be produced in large quantities allows researchers to make progress in regenerative medicine, using these cells to develop new functional cells, tissues, and organs. The healthy cells are implanted into the patient, serving as treatment to permanently repair failing organs (Holland 5). The otherwise lack of treatment for loss of organ function displays the valuable potential of embryonic stem cells.
The sources of embryonic stem cells are a main point of controversy in the debate regarding embryonic stem cell research. Some possible sources for these stem cells include embryos created via in vitro fertilization (for either research or reproduction); five-to-nine-week old embryos or fetuses obtained through elective abortion; and embryos created through cloning or what is known as somatic cell nuclear transfer (Liu 1). Somatic cell nuclear transfer is the laboratory creation of a viable embryo by implanting a donor nucleus from a body cell into an egg cell. The ethics of obtaining embryonic stem cells via these sources can be questionable and have led to disputes that I will later address.
Research utilizing human embryonic stem cell lines has focused on the potential to generate replacement tissues for malfunctioning cells or organs (Liu 1). A specific technique has been isolated to utilize stem cells in order to repair a damaged tissue or organ:
"If a damaged tissue or organ cannot repair itself, stem cells could be obtained from these different stem cell sources [organs and tissues from individuals after birth; gametes, tissues, and organs from aborted fetuses; inner cell mass of early embryos]. Scientists could then culture these stem cells by creating conditions that enable them to replicate many times in a petri dish without differentiating. Such a population of proliferating stem cells originating from a single parent group of stem cells is a stem cell line. Stem cells from this stem cell line could then be coaxed to differentiate in to the desired cell type, and be transferred into the patient so that they can repair the damaged tissue or organ" (Devolder 6).
Other examples of research efforts include treatment of spinal cord injury, multiple sclerosis, Parkinson's disease, Alzheimer's disease, and diabetes. Researchers also hope to use specialized cells to replace dysfunctional cells in the brain, spinal cord, pancreas, and other organs (2).
Federal funding of embryonic research has been strictly regulated since 1994 when President Clinton declared such research would not be funded by the government. Following this executive order, Congress passed the Dickey Amendment in 1996, prohibiting "federally appropriated funds from being used for either the creation of human embryos for research purposes or for research in which a human embryo or embryos are destroyed, discarded, or knowingly subjected to risk of injury or death" (Liu 2). Embryonic research has continued nonetheless by means of alternative funding. In 2001, President Bush declared that federal funding would be granted to human embryonic research on a restricted basis. However, these funds were only to be awarded for research on already existing stem cell lines. No funding was to be granted for "the use of stem cell lines derived from newly destroyed embryos, the creation of any human embryos for research purposes, or cloning of human embryos for any purposes" (3-4).
The debate over funding for embryonic stem cell research depends heavily on the ethical status of the research. There are two main arguments surrounding the ethics of embryonic stem cell research: the research is ethical because of the unique potential that embryonic stem cells have to cure currently untreatable diseases; and the research is unethical because it requires the destruction of life in the form of an embryo or fetus. Ultimately, the possible benefits and controversial status of life that an embryo embodies qualify embryonic stem cell research as ethical, as long as the stem cells are obtained in an ethical manner.
Arguments for Embryonic Stem Cell Research
In the realm of stem cell research, embryonic and adult stem cells are often compared. The controversial use of embryonic stem cells is supported on the basis of the many advantages that they have over adult stem cells. Embryonic stem cells are easier to obtain; they have a greater cell growth, otherwise known as proliferation, capacity; and they are more versatile. Embryonic stem cells are isolated from embryos in the blastocyst stage and the process damages the structure of the embryo to a point from which the embryo can no longer develop. Because these stem cells are obtained at a point when the inner cell mass is concentrated in the embryo, they are more easily obtained than adult stem cells, which are limited in quantity. Another valuable benefit of embryonic stem cells is their ability to multiply readily and proliferate indefinitely when cultured in the proper conditions (Devolder 9). Lastly, embryonic stem cells' pluripotent quality is the main factor that distinguishes them from adult stem cells (10). The ability to differentiate into any cell type creates greater possibilities for the application of embryonic stem cells.
Supporters of embryonic stem cell research argue that the research is justified, though it requires the destruction of an embryo, because of the potential for developing cures and preventing unavoidable suffering. These backers often disagree with the belief that "a blastocyst – even one that is not implanted in a woman's uterus – has the same ethical status as a further-developed human" (Clemmitt 702). Arthur Caplan, professor of medical ethics at the University of Pennsylvania, asserts that "an embryo in a dish is more like a set of instructions or blueprint for a house. It can't build the house. For the cells to develop into a human being requires an interactive process in the uterus between the embryo and the mother" (Clemmitt 702).
Others in favor of the research, such as Heron, a biotechnology company, claim that "not to develop the technology would do great harm to over 100 million patients in the United States alone who are affected by diseases potentially treatable by the many medical applications of hES [human Embryonic Stem] cells" (Holland 11-12). One example is the previously stated method of using embryonic stem cells to repair damaged tissue or organs. The only way to restore cellular function in an organ is to literally replace the lost cells and embryonic stem cells provide the best option for producing these cells (3).
Embryonic stem cells do also have some disadvantages that should be considered when making the argument for further support of embryonic stem cell research. Unlike adult stem cells, embryonic stem cells have a higher risk of causing tumor formation in the patient's body after the stem cells are implanted. This is due to their higher capacities for proliferation and differentiation (Devolder 11). Embryonic stem cell-based therapies also possess the risk of immunorejection – rejection of the stem cells by the patient's immune system. Because embryonic stem cells are derived from embryos donated for research after in vitro fertilization treatment, the marker molecules on the surfaces of the cells may not be recognized by the patient's body, and therefore may be destroyed as the result of a defense mechanism by the body (Holland 11). This is a problem that will require a solution if embryonic stem cell research is to be the basis for future therapeutic medicine.
Arguments against Embryonic Stem Cell Research
Currently, the isolation of embryonic stem cells requires the destruction of an early embryo. Many people hold the belief that a human embryo has significant moral status, and therefore should not be used merely as a means for research. One position that opponents of embryonic stem cell research assert is what "The Ethics of Embryonic Stem Cell Research" calls the full moral status view (14). This view holds that "the early embryo has the same moral status, that is, the same basic moral rights, claims, or interests as an ordinary adult human being." This moral status is believed to be acquired at the point of fertilization or an equivalent event such as the completion of somatic cell nuclear transfer. Therefore, with full moral status as a human being, an embryo should not be deliberately destroyed for research purposes simply because it is human (Devolder 15). The Roman Catholic Church is a strong supporter of this view, opposing stem cell research on the grounds that it is a form of abortion. Several other groups, including American evangelicals and Orthodox ethicists, consider "blastocysts to have the same status as fully developed human beings" and therefore oppose embryonic stem cell research for this reason. Beliefs regarding the moral status of an embryo are subjective, and also their own controversial issue, which complicates the task of creating a universal law for the use of embryonic stem cells for research.
Others in opposition, such as Kevin T. Fitzgerald, a Jesuit priest who is a bioethicist and professor of oncology at Georgetown University Medical School, do not consider the moral status of an embryo, but rather assert that Embryos should be protected because they are "that which we all once were" (Clemmitt 701). This view is very similar to moral philosopher and professor of philosophy as the University of California at Irvine Philip Nickel's "Loss of Future Life Problem" in regards to embryonic stem cell research. The Loss of Future Life Problem holds that it is unethical to take the lives of future humans by destroying embryos for research (Tobis 64). This stance stresses the potential of those future lives that will never have the chance to reach fulfillment if destroyed for research. In a retroactive sense, this can cause us to question "what if the embryo that developed into Albert Einstein was destroyed for embryonic stem cell research?" It is impossible for one to know the value that is lost in each embryo taken for research purposes, if that embryo is created with the plan of developing into an adult human being.
The response to this problem is that the particular blastocysts that are harvested for embryonic stem cell research are taken from (1) embryos that are frozen during in vitro fertilization procedures and never implanted, (2) donated egg cells, and (3) embryos created specifically for the purpose of generating new stem cell lines. In each of these cases, the embryo at hand does not have a future life in plan and therefore, nothing is lost by using such embryonic stem cells for research. For embryos created via in vitro fertilization, the researchers using the embryos are not making a decision that results in the loss of a future life. The future life of said embryo is lost when the decision is made to not implant it. Therefore, the Loss of Future Life Problem is not a valid objection to research using embryonic stem cells from frozen IVF embryos that are never implanted. Donated egg cells can be fertilized in a lab or through somatic cell nuclear transfer, a process described earlier in this paper. Embryos created specifically for the purpose of contributing to stem cell research have no actual future life to be lost from the moment of conception. In both of these cases, the intent of fertilization is not to create a future adult human being, and so the Loss of Future Life Problem does not apply to these sources of embryonic stem cells.
"In terms of the Loss of Future Life Problem, the key question is again whether the embryo is being deprived of future life, and again the answer depends on whether the embryo is removed from a woman's reproductive system, in which case it is likely that it is being deprived of future life that it would otherwise go on to have. If fertilization takes place outside a woman's body, by contrast, then the embryo is not already on its way toward a future life, so destroying it does not deprive it of that particular future" (Tobis 66-67).
As shown by the various arguments in this essay, the debate over embryonic stem cell research is a multifaceted scientific, moral, ethical, and political issue. Embryonic stem cells, with their pluripotent potential and self-renewing quality, hold great value for scientific researchers in search of cures for untreatable diseases, progress in regenerative medicine, or a better understanding of early human development. However, the ethical question still arises, "do the ends justify the means?"
Varying views regarding the ethical status of an embryo answer this question in different ways, though it is commonly accepted that if the means of obtaining the embryonic stem cells are ethical, then the resulting research of those stem cells is also ethical. For example, if a donated egg is fertilized in a lab with the intention of being used for future research purposes, the resulting research is therefore morally justified.
This is not to be said that the life of an early-stage embryo is to be taken lightly. More so that our moral perception of these embryos is different than that of a later-stage fetus, an infant, or an adult human being. Phillip Nickel asserts this subconscious difference, claiming that,
"while it's well known that many embryos are shed naturally, in very early abortions and miscarriages, no one makes an effort to save or grieve for them, as frequently happens with later-stage fetuses. This shows that people do view embryos as somewhat different from people, even though they may not realize it" (Clemmitt 702).
Thus, the moral distinction between a blastocyst and a developed fetus weakens the moral arguments in opposition to embryonic stem cell research. After all, if this research can reduce suffering for thousands of people, are we not morally obligated to pursue it?
Scientists in support of embryonic stem cell research are currently restricted by the limited amounts of federal funding and embryonic stem cell lines available for research. Many argue that these restrictions are preventing further scientific development and weakening the United States' position as a leading nation in biomedical research. Some scientists worry that if strict regulations of stem cell research continue, private companies may bypass the standards put in place by the National Institute of Health and conduct unregulated research (Clemmitt 700). If the United States wishes to remain a premiere country in biomedical research and maintain order and control of embryonic research being performed, action must be taken to address this issue.
Overall, though the destruction of a life is typically held to be unethical, the moral status of an embryo in the blastocyst stage is unclear and therefore cannot be equated to the moral status of an adult human being. Also, ethical sources of embryonic stem cells exist that do not take the life of future beings (i.e. unwanted frozen embryos produced via in vitro fertilization, donated egg cells fertilized in a laboratory). For these reasons, in combination with the possibility of reducing suffering for future beings, embryonic stem cell research is ethical under certain circumstances. As long as the stem cells are isolated in a manner that does not harm an embryo with the plan of developing into an adult human, the subsequent research is ethically justified. With this in mind, embryonic stem cell research should receive greater government funding so that continued progress can be made.
1 In cell division, a parent cell divides into two or more daughter cells.
Belin Mirabile was born and raised in Phoenixville, Pennsylvania, a suburb of Philadelphia. She is currently majoring in Mechanical Engineering at Notre Dame with a minor in Catholic Social Tradition. When tasked with the assignment of writing a rhetorical essay that evaluates a point of ethical controversy, Belin wanted to choose a topic that relates to her interest in Bioengineering. Embryonic stem cell research stood out as a current issue that would be interesting to evaluate in the form of a researched essay. After her four years at Notre Dame, Belin plans to pursue a career related to Bioengineering that contributes in some fashion to the betterment of human health. Belin would like to thank her Writing and Rhetoric professor, John Duffy, for transforming her opinion of writing and giving her every tool to be a successful writer.
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