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.
Clemmitt, Marcia. "Stem Cell Research." CQ Researcher 1 Sept. 2006: 697-720. Web. 25 Nov. 2015.
Devolder, Katrien. The Ethics of Embryonic Stem Cell Research. First ed. 2015. Issues in Biomedical Ethics. Print.
Holland, Suzanne, Lebacqz, Karen, and Zoloth, Laurie. The Human Embryonic Stem Cell Debate: Science, Ethics, and Public Policy. Cambridge, Mass.: MIT, 2001. Basic Bioethics. Web. 17 Nov. 2015.
Liu, Edward Chan-Young. Background and Legal Issues Related to Human Embryonic Stem Cell Research. American Law Division, 2008. Print.
"The Ethics of Embryonic Stem Cell Research." Embryo Politics. Ithaca; London: Cornell UP, 2011. 120. Print.
Tobis, Jerome S., Ronald Baker Miller, and Kristen R. Monroe. Fundamentals Of The Stem Cell Debate : The Scientific, Religious, Ethical, And Political Issues. Berkeley: University of California Press, 2008. eBook Collection (EBSCOhost). Web. 17 Nov. 2015.
Cloning and Stem Cells
Cloning, including reproductive and therapeutic cloning, is an emerging technology. In this essay, I focus on the implications of this powerful yet controversial technology and how it can influence our lives. As a scientist working on stem cells, I also feel I have an obligation to discuss these technologies, their potential and the ethical issues they raise.
From Clones to Dolly
Clones are genetically identical organisms. In other words, organisms with the same DNA or genome. Organisms with asexual reproduction, like many microorganisms that merely divide, usually have millions of clones because only rare mutations are a cause of genetic alterations. In mammals, including humans, clones can originate due to divisions of the egg, often called identical or monozygotic twins. Having the same genome does not imply that two organisms will be exactly the same. Even identical twins are different to some degree. During development random events occur, called developmental noise, that are unique to each organism. In addition, changes in education, nurturing, and other environmental factors can lead to noticeable differences between adult organisms with the same genome.
In 1997, Ian Wilmut and colleagues at the Roslin Institute in Scotland developed an artificial method of obtaining mammalian clones from mature animals and thus permit asexual reproduction in mammals. Dolly the sheep was the first such cloned mammal--cloning in other species, like frogs, had been done before. Briefly, clones are generated by extracting the nucleus of a mother cell, which in case of Dolly was a mammary cell, and then injecting it into an egg without a nucleus. Precise cell culture conditions and often an electric shock allow the nucleus to merge with the egg which can then be inserted into a womb and, in some cases, generate a new organism. This procedure--known as nuclear transfer--meant that Dolly featured the same nuclear genome of her "mother". In recent years, clones of many other mammalian species have been produced using this or similar techniques: calves, mice, monkeys, pigs, cats, etc. Clones from clones have also been created.
Animal cloning has many applications. Cloning pets is already a reality and some companies offer services in this area. In agriculture, researchers have cloned a disease-resistant bull that had died and the cloning of endangered species is an emerging prospect for conservation efforts. Despite some early setbacks, Pasqualino Loi and colleagues have been able to clone a mouflon lamb, a member of an endangered species of sheep, using the same somatic cell nuclear transfer technique used to clone Dolly. Cloning animals is barely controversial, though human cloning has been much attacked, as detailed below.
The Dangers of Human Cloning
The greatest danger human cloning poses is a health risk to babies born through this procedure if it were attempted with current technology. Research in animals has shown that while cloning is possible, the majority of animals die at early stages of development or shortly after birth. Moreover, a number of cloned animals are born with defects. Despite anecdotal claims, human cloning has never been performed, yet one serious possibility is that human clones would also feature birth defects. A possible cause for defects in clones are epigenetic changes. Succinctly, in addition to the DNA, there is another layer of information in the genome called the epigenome. Genes can be turned on and off through chemical modifications of the DNA. Clones derived from adult cells do not have the epigenetic patterns found in a newly born, and so they could carry defects. For this reason, the vast majority of researchers, including myself, opposes reproductive cloning in humans.
There have been other concerns raised, though these are more far-fetched. Can a mad dictator create an army of elite troops using clones? Sure he can. It is, however, a rather clueless thing to do because it wouldn't be economically viable. It would require a large amount of resources, not to mention years in research and waiting for the clones to grow. Certainly, it is much easier, quicker, and cheaper to recruit and train adults than to create human clones. Or follow the example of dictator Ceausescu of Romania who recruited young orphans to train them for his special forces.
"Cloning may turn out to be less prevalent and less scary than we imagined. Market forces might make reproductive cloning impractical, and scientific advancements may make it unnecessary." Robin Marantz Henig
Fortunately, the costs of reproductive cloning are prohibitive for most people and with current legislation aiming at preventing human cloning, it is doubtful that many human clones will be born (if any at all), at least with current technology. It is possible future technological breakthroughs make human cloning a safe and cheap option, but with improvements in reproductive medicine and genetic engineering, it is unlikely human clones will become a reality any time soon. By and large the alarmist concerns associated with human cloning are unfounded.
Cloning, Stem Cells, and Their Impact on Medicine
"Therefore to him that knows to do good, and does it not, to him it is sin." The Bible (James 4:17)
The future of cloning is really at the cellular level, also called therapeutic cloning. It is possible to obtain blastocysts, which are a mass of undifferentiated cells, from eggs generated via nuclear transfer techniques like the one used to create Dolly. (Although scientists at Advanced Cell Technology succeeded in creating human embryos from clones, for therapeutic cloning this is not necessary.) Each of the cells in the blastocyst has the potential to generate an individual, a clone of the patient. Strikingly, these undifferentiated cells, also called embryonic stem cells, can give rise to any type of tissue. Therefore, cloning makes it possible to obtain these stem cells from an adult patient which can then used to treat a myriad of diseases. Because cells created using therapeutic cloning are genetically equal to the patient's there are few or no problems of immune system rejection.
Mouse embryonic stem cells derived from the inner mass of the blastocyst. The large aggregates are colonies of cells. These cells can be used to create transgenic mice or they can be differentiated into different types of tissues, including neurons, pancreatic insulin-secreting cells, etc.
Much research is being done in therapeutic cloning and stem cells to develop treatments for life-threatening disease such as AIDS, Parkinson's disease, Alzheimer's, diabetes, etc. Therapeutic cloning is part of the broader emerging field of regenerative medicine, which also includes using stem cells derived from adult tissues, and has applications in various injuries and debilitating conditions. The general strategy involves collecting cells from the patient, creating totipotent cells from the blastocyst using nuclear transfer techniques, differentiating the cells into the necessary tissue type, multiplying the cells, and implanting the cells back again. For instance, it may be possible to use cells obtained this way to replace the dying neurons in Alzheimer's disease and even aging may be amenable to treatments with stem cells. It is also possible to correct genetic errors in the stem cells and therefore provide new treatments for patients with genetic diseases. Overall, the potential stem cells have is enormous and as engineering problems are progressively solved, this field has the capacity to change the face of medicine.
Many politicians and bioethicists have opposed research using embryonic stem cells by drawing parallels between the methods used to derive stem cells and abortion. These comparisons are misleading, though. Unlike in abortions, an individual is not destroyed to generate embryonic stem cells. The blastocyst is not an embryo as it will not give rise to an individual. Instead, it is a cellular mass that has the potential to yield one, two, three, or more individuals. As such, the blastocyst cannot be considered an individual. Misleading criticism of therapeutic cloning is particularly unfortunate because it is hindering research that can save thousands of lives.
For some tissues it is possible to derive stem cells from adults without the need of a blastocyst. These adult stem cells are, however, less powerful than embryonic stem cells and have more limited applications and that is why researchers prefer to use embryonic stem cells. Another alternative to avoid ethical concerns regarding the use embryonic stem-cell research is a technique called induced pluripotency (iPS) which allows adult cells to be transformed into pluripotent cells. This revolutionary technique developed by the lab of Shinya Yamanaka in Japan has generated great excitement, though it should be said that stem cells created with iPS are not yet proven to be safe for the clinic.
No doubt much more research is necessary to fully exploit the potential of therapeutic cloning to generate patient-specific undifferentiated stem cells. A number of technical hurdles remain, though clinical trials for a variety of conditions, including cardiovascular and neurological diseases, are ongoing. The strict requirements for extensive clinical trials imposed by governments mean that years will be necessary to bring these treatments to patients. In that sense, I do think (and many other scientists agree) that for serious, untreatable conditions more relaxed clinical trials would allow for faster progress. In many cases of terminal diseases patients have nothing to lose and many would volunteer to participate in trials, hence governments should allow companies and researchers to take more risks with experimental treatments in such extreme conditions.
In conclusion, I'm convinced that human cloning and genetics are going to play a critical role in the future of medicine. My lab already conducts research on stem cells and I feel lucky to have the opportunity to embark on this exciting journey. I hope politicians and the public in general see the benefits of stem cell research are much greater than its problems.
Sources and Links
Clonaid; controversial company that claim to be the first to offer human cloning.
Bio Arts; pet cloning.