Asian Bioethics Review (2017) 9:33–44 DOI 10.1007/s41649-017-0010-3 O R I G I N A L PA P E R
Is Human Embryonic Stem Cell (HESC) Research Still Necessary Today? Patrick Chee-Kuen Foong 1
Published online: 30 June 2017 # National University of Singapore and Springer Nature Singapore Pte Ltd. 2017
Abstract Given the promise of stem cell therapies, scientists throughout the world are conducting stem cell research using various kinds of stem cells including human embryonic stem cells (HESC). However, HESC research is very controversial in some societies as the extraction of stem cells involves the destruction of the human embryo. The ethical concerns of this kind of research have led scientists to search for other methods to derive stem cells that do not involve the destruction of embryos. These different types of stem cell research are said to sidestep the ethical dilemma associated with HESC research and so are considered as ethically acceptable ways to obtain stem cells; possibly, they may even mark the end of HESC research. However, each of these stem cell methods presents its own challenges, scientific and ethical, as this article explores. This paper examines the impact of the emergence of different types of stem cell research and discusses whether it is still necessary for scientists to conduct the contentious HESC research. Keywords Stem cell research . Embryo research . Induced pluripotent stem cell research . Comparative ethics
Introduction Stem cells hold great potential for scientific research. Since the use of stem cells in regenerative medicine with the emergence of bone marrow-derived stem cell transplants in the 1960s, scientists have had high expectations for their therapeutic use in treating a wide variety of devastating illnesses and conditions such as diabetes, heart disease and spinal injuries. Researchers around the world are conducting stem cell research using different kinds of stem cells including the highly controversial human Law lecturer, Western Sydney University, Sydney, Australia
* Patrick Chee-Kuen Foong
[email protected]
1
Western Sydney University, Sydney, Australia
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embryonic stem cells (HESC). While HESC research raises serious ethical concerns with the primary concern being that extraction of stem cells from a human embryo involves its destruction, it should also be noted that the other types of pluripotent stem cell research are not without any ethical issues, as will be explored in this paper. In spite of its controversies, embryonic stem cells are nevertheless regarded by some scientists as the gold standard of stem cell research. These cells have the unique abilities to self-renew. They are easy to identify, isolate, maintain and grow in the laboratory. On an important note, embryonic stem cells are pluripotent; this means they have the capacity to generate/differentiate into every cell type in the human body to develop bones, skin, organs and other body parts that patients with injuries or illnesses in need of transplants will benefit from receiving. While tissues and organ cells can be transplanted, a major issue is a lack of donors. The scientific importance of using embryonic stem cells as research tools is that they have unique properties since they are unspecialised, and are able to divide and renew themselves for long periods of time. Potentially, these cells will allow the growth of required tissue when it is needed. In 2013, a team led by Shoukhrat Mitalipov at the Oregon Health & Science University and the Oregon National Primate Research Center attained a scientific first by creating embryonic stem cell lines from cloned human embryos through therapeutic cloning/somatic cell nuclear transfer (SCNT) research using cells from infants (Tachibana et al. 2013). In the following year, researchers at the Research Institute for Stem Cell Research at CHA Health Systems in Los Angeles have produced stem cells using SCNT, from adults, bringing them closer to developing patient-specific cell lines (Chung et al. 2014). And in 2016, researchers in China believe they have developed a solution to male infertility by creating sperm out of embryonic stem cells (Zhou et al. 2016). The ethical concerns about HESC research have motivated scientists to explore other methods to derive stem cells that do not involve the destruction of the human embryos. These stem cell alternatives, which include the creation of cells with equivalent or similar powers, are thought by some as morally and ethically acceptable ways to obtain stem cells. They are said to sidestep the ethical quandaries associated with HESC research and if this is the case, HESC research should not be pursued by scientists. This paper examines whether such innovative science will completely resolve the stem cell ethical controversies and whether the emergence of various stem cell techniques that do not involve the destruction of embryos would mean that the highly controversial HESC research is no longer necessary today.
The Controversies of Human Embryonic Stem Cell Research In the western world, there have been discussions about the moral status of the embryo with the inquiry of when ensoulment happens since the sexual revolution of the 1960s with the discovery of the birth control pill and debates on the legality of abortion.1 The discussion resurfaced in 1978, when the world’s first in vitro fertilisation (IVF) baby 1
Roe v. Wade 410 U.S. 113 (1973).
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was born. 2 The creation of Dolly, the sheep, in 1997 generated fresh discussions on issues arising from cloning and stem cell research, which included the moral debate of embryos as found in the reports in various countries like the USA (President Council’s on Bioethics 2002) and Australia. 3 This matter continues to be contentious in the discussion of the use of reproductive technologies all over the world. The key to the argument of the moral status of the human embryo is the moment at which personhood is obtained. In Anglo-Western literature, this concept is debated ethically with three views put forward. These different views reflect the diversity of opinion in societies. The first view, which is drawn from scholarly sources, is that the human embryo has no intrinsic moral status and therefore its destruction is not morally problematic. The reason is that the early embryo is not yet endowed with the properties of sentience or rationality. As Russell Blackford argues: ‘The early embryo does not fear death, incapable of planning, of identifying with political causes or falling in love, with no networks or kin, loved ones, dependents or colleagues and cannot commit itself to any projects that give it reason or to want to go on living and developing. It has no wants’. 4 From a Feminist viewpoint, Judith Jarvis Thomson claims that the best metaphor to describe the status of the embryo is that of a parasite, possessing no moral status independent of the mother. 5 It depends completely on the mother for its development. Only at the time of birth is the baby recognised as a person. Before that, the embryo is merely a bundle of cells, waste product or by-product of an ART programme (Chalmers and Nicol 2003). The second view is that the embryo has intrinsic moral and legal status equivalent to a baby or an adult. From the point of conception, that is, when the sperm meets the egg, the development of the person commences. This is largely influenced by religions such as the Catholic faith. During this moment, the individual DNA code is imprinted in the embryo, signifying the start of a fresh human existence and unique personal identity.6 The creation of a person is connected to the consummation of an act by participants in its inception. The moral status of the embryo equates to an adult human being and it is considered that it is morally wrong and unacceptable to harm the embryo even for a good cause. The use of an embryo for research purposes is also regarded as ethically problematic because appropriate consent could not be obtained. The third view lies in between these two extremes: the embryo enjoys some moral status but less than an adult human being. In Roe v. Wade,7 the Supreme Court of the USA held that pregnancy could be split into three periods, three trimesters with each period corresponding to the degree to which the embryo has developed. It provides that 2
The birth of Louise Brown, Department of Health and Social Security, Report of the Committee of Inquiry into Human Fertilisation and Embryology (1984) Cmnd 9314 (Warnock Report). 3 Australian Health Ethics Committee of the National Health Medical Research Council, Scientific, Ethical and Regulatory Considerations Relevant to Cloning of Human Beings (1998) Canberra (AHEC Report), House of Representatives Standing Committee on Legal and Constitutional Affairs, Human Cloning: Scientific, Ethical and Regulatory Aspects of Human Cloning and Stem Cell Research (2001) Canberra (Andrews Report). 4 Professor Russell Blackford of the School of Philosophy and Bioethics, Monash University (Blackford 2006). 5 Professor Judith Jarvis Thomson, a philosopher at the Massachusetts Institute of Technology (MIT) (McGee et al. 2004). 6 Ibid at 98. 7 410 U.S. 113 (1973).
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‘for the stage prior to approximately the end of the first trimester, the abortion decision and its effectuation must be left to the medical judgment of the pregnant woman’s attending physician … For the stage subsequent to approximately the end of the first trimester, the State, …., may, if it chooses, regulate the abortion procedure in ways that are reasonably related to maternal health … For the stage subsequent to viability, the State …. may, if it choose, regulate, and even proscribe, abortion …’. 8 Each term represents the increasing standing of the emerging person in society. An embryo begins with little or no moral status; as it grows, it gains more status and continues to attain more. It is useful to refer to the President’s Council report which raised an important point to illustrate this third view, ‘In our view, embryos have a developing and intermediate moral worth, such as that the early human embryo has a moral status somewhere between that of ordinary human cells and that of a full human person. We acknowledge the difficulty of setting perfectly clear line marking when an embryo’s moral status goes from ‘less than a human person’ to ‘like a human person’ to ‘full a human person.’ But we believe there are sound moral reasons for not regarding the embryo in its earliest stages (certainly in the first fourteen days) as the moral equivalent of a human person, though it does command significantly more respect than other human cells. We also hold that the embryo can be used for life-saving or potentially life-saving research while still being accorded the ‘special respect’ it deserves, and while still preventing abuses such as research on later-stage embryos or fetuses or the production of cloned children ...’9 This report refers to the example of the practice of sacrificing the life of the unborn foetus to save the life of a pregnant woman. It claims that this reveals ‘moral precedent for subordinating nascent human life to a more developed human life.’10 The report also provides that it is possible to accord the embryo with due respect while using it for research. 11 By analogy, it cites the example of hunters, who may have respect and probably even affection for the animals they kill. It argues that the embryos should be given the respect in that they are used for serious and not frivolous reasons. These three conflicting views are often present in debates about the moral status of the human embryo in the western societies. It is very difficult or even impossible to reconcile them, hence their controversy.12
Types of Stem Cell Research that Do Not Involve the Destruction of Human Embryos: an Ethical Analysis In this section of the article, the various types of stem cell research that do not involve the destruction of the embryos are discussed and the ethical implications of each technique are explored. If these techniques also raise ethical issues, these considerations
8
Ibid at 165. President’s Council Report at 153. 10 Ibid at 155–156. 11 Ibid at 156–157. 12 The President Council’s on Bioethics has conducted an ethical analysis of some of these stem cell alternatives, namely stem cells from already deceased embryos, PGD and ANT published in a white paper; see ‘Alternative Sources of Human Pluripotent Stem Cells’ (2005) The President’s Council on Bioethics. 9
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will cast doubt as to whether these types of stem cell techniques would suggest that the contentious HESC research should not be pursued. Stem Cells from Non-viable Embryos This method proposes the use of human embryos for stem cell research when they are organismically dead. An analogy can be drawn between the harvesting of cells from dead embryos and end-of-life organ donation. Stem cells can be removed from a nonviable embryo akin to organ harvesting once a person is certified to be medically dead. A person could arguably be considered as organismically dead if the function of the brain is irretrievably lost. The cells and organs of a dead human body may continue to function for a period after they have died. Thus, the same argument that justifies harvesting organs from brain-dead humans could be extended to cover extracting stem cells from non-viable human embryos. With appropriate consent, it is acceptable to use cadaver organ donation for research or transplant, and the use of non-viable human embryos is no different. Since the stem cells are obtained from an embryo that is already non-viable, an important ethical obstacle will be removed (for those who adopt the second viewpoint which regards the embryo as equal to an adult human being). There is a supply of non-viable human embryos from in vitro fertilisation that are not needed for their original reproductive purpose. First, the frozen embryos are thawed. Donald Landry and Howard Zucker of Columbia University proposed that an embryo is classified as technically dead when it has not undergone cell division for not less than 24 h (Landry and Zucker 2004). It was also suggested that the absence of the transcription factor OCT4, also known as POU5FI, a determinant of growth and differentiation, indicates the death of the embryo.13 As these embryos have irreversibly lost the cellular division, growth and differentiation, they are non-viable and it can be argued that their use in research after appropriate consent from their biological parents has been obtained is morally and ethically justifiable. To create a stem cell line from a non-viable embryo, some viable cells must exist (Green 2008a). Clinical experience indicates that embryos with severe impairments have nonetheless progressed to normal development. It is still not agreed on what the moment of ‘death’ looks like in an embryo as the absence of vital organs, such as heart or brain, makes it a challenge to determine organismic death with certainty. Thus, it is questionable whether ‘biomarkers of sufficient reliability to certify death could be found’.14 Stem Cells from Chromosomally Abnormal Embryos Human embryos that are confirmed to be chromosomally abnormal are set aside in in vitro fertilisation (IVF) and will not be transferred to the womb of the patient. The confirmation of a chromosomally abnormal embryo is performed by pre-implantation genetic diagnosis (PGD), also called pre-implantation genetic screening (PGS). Only healthy embryos are transferred but not those deemed unsuitable for reproductive use. The stem cell lines derived from the chromosomally abnormal embryos will be useful 13 14
Ibid. Ibid.
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in studying disease progression and faults in embryonic development, and to improve knowledge of genetic diseases. A study indicated that chromosomal self-normalisation occur in some chromosomally abnormal embryos, which could render more complex the determination of ‘abnormality’ (Munne et al. 2005). There is opposition from people who argue that as some of these chromosomally abnormal embryos may normalise, this process amounts to the killing of healthy and viable human beings. Some (such as those who adopt the second viewpoint that regards the embryo as equal to an adult human being) also argue that the use of human embryos that are deemed genetically flawed is unethical, as they consider this to be analogous to exploiting disabled people.15 However, it is uncertain whether chromosomally abnormal embryos can provide stable and safe stem cell lines for eventual therapeutic use (Green 2008a). These embryos are likely to be genetically compromised and they may not be usually considered as appropriate sources of stem cell lines. Stem Cells from Pre-implantation Genetic Diagnosis/Single-Blastomere Biopsy/ Live Embryo Biopsy In PGD, before the IVF embryo is implanted in the mother, a biopsy is performed on the embryo by removing a cell from it. Such biopsies are routinely done to verify that an embryo does not harbour a genetic disease. The cell is tested for any of 150 genetic defects, giving the parents the choice of implanting an embryo that is disease free. During the eight-cell stage (3-day embryo), a single cell/blastomere is removed by micromanipulation (Vogel 2006). The remaining seven-cell embryo can be implanted into the uterus to produce a pregnancy. After being cultured overnight, the cell that is removed divides into two cells. One cell could be used for genetic diagnosis of inherited diseases and the other for the creation of an embryonic stem cell line. Every child born through PGD could have its line of embryonic cells banked for the future.16 Robert Lanza and colleagues at a biotechnology company, Advanced Cell Technology (ACT), reported the process of using single-blastomere biopsy (SBB) to develop pluripotent mouse stem cell lines (Lanza et al. 2005). In the following year, it said that it had repeated this experiment with human embryos, this time with thawed ones that were donated for research by couples undergoing IVF treatments (Lanza et al. 2006). With 16 embryos, they obtained two stable embryonic stem cells (Abbott 2006). Ninety-one cells were taken from 16 embryos and with the creation of only two stem cell lines, this technique was not efficient. Also, the second paper has been criticised as all 16 human embryos had been destroyed.17 There are ethical issues with PGD biopsy. According to James Battey, chair of the Stem Cell Task Force at the National Institutes of Health (NIH), the PGD biopsy carries some risk to the human embryo. 18 While this view is shared by Norio Nakatsuji of Kyoto University, he said that the risk to the embryo is small. 19 However, Michelle LaBonte said that the impact of PGD on the long-term health effects on the child is not proven and many IVF clinics do not reveal any risks (Cook 2012). Concerns remain 15
Ibid. Ibid. 17 Ibid. 18 Ibid. 19 Ibid. 16
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over the disposal of embryos and derivatives from PGD. Richard M. Doerflinger, deputy director of the United States Conference of Catholic Bishops, expressed the concern that PGD diagnosis itself is not ethical as this method is performed to select genetically deficient embryos for disposal and also poses threats of future harm to the child permitted to be born (Wade 2005). Lastly, Markus Grompe from Oregon Stem Cell Center at Oregon Health & Science University said that ‘removing a single cell might be creating two embryos (one of which would be destroyed), since the eight-cell embryos can naturally divide to produce twins’ (Hall 2006). Stem Cells From Altered Nuclear Transfer/Bioengineered Embryo-Like Artifacts The altered nuclear transfer (ANT) technique, proposed by William Hurlbut, a member of the President’s Council on Bioethics in the USA, involves the creation of an embryolike entity with altered DNA where the entity is engineered to lack the capacity to develop into a human being but will produce usable stem cells. The process is the similar to SCNT but hinders the resulting embryo’s developmental capacity. The somatic cell nucleus that would be transferred into the egg would be genetically altered in vitro and no embryo is generated (Green 2008a). The gene CDx2 that is ‘responsible for placental developmental is switched off [and] the resulting entity would lack the capacity to the self-directed integrated organic function that is essential for embryogenesis.’20 Hurlbut’s theory is constructed on the observation that a mouse embryo with a modification in the Cdx2 gene dies during the blastocyst phase since it fails to develop a trophectoderm from which the placenta normally grows (Hurlbut 2004). He argues that a human embryo with a similar mutation would lack the capacity to become a human being and thus represent an ethically uncontroversial source of embryonic stem cells. He said the resulting entity would have ‘… no inherent principle of unity, no coherent drive in the direction of the mature human form and no claim on the moral status due to a developing human life.’21 He has described them as biological artifacts, a human creation for human ends. Like the SCNT process, human eggs are needed in the ANT technique. The same ethical concerns surrounding exploitation of women arise such as informed consent, payment to the egg donors and risks to their health (it is beyond the scope of this article to explain these issues in greater detail). 22 The idea of purposely creating defective embryos has met with serious objections from ethicists especially from those who equate an early human embryo with a human being. It attracts the same arguments that dissenters have expressed about SCNT. They explain that the ANT embryo grows normally until the Cdx2 function is needed, at which point it dies (Melton et al. 2004). The ANT process has even been compared to the deliberate making of an anencephalic infant, without a cerebrum, as an organ donor (Green 2008b). Some stem cell researchers have also expressed concerns with this technique (Melton et al. 2004). Genetic manipulation is a scientific challenge. It is uncertain whether the impairment of 20
Ibid. Ibid. 22 See also L Knowles, ‘Commercialization and Stem Cell Research’ (2010) Stem Cell Network 1 (Waldby et al. 2013). 21
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Cdx2 affects the utility of the stem cells and whether it is possible to reactivate the gene when required (Green 2006). Stem Cells from Parthenogenesis Parthogenes are gametes (or sex) cells such as sperm and eggs that naturally lack complete developmental capacity. 23 Parthenogenesis is asexual reproduction naturally occurring among some insects, lizards and birds. The technique of parthenogenesis involves the manipulation of female gametes/eggs through electrical and chemical stimulations. This parthenogenic activation induces an egg to divide without fertilisation by sperm. A team of scientists from the Harvard Stem Cell Institute has reported the isolation of parthenogenetic embryonic stem cells (PESC) in mice. Unlike the process of ANT discussed above, this process does not involve the deliberate impairment of an embryo-like entity as the parthogenes naturally do not have the ability to develop into foetuses. Only gametes, in this case, eggs, are manipulated rather than embryos. At present, the value of this method is uncertain. There is the question of whether it is possible to extend this technology to human cells. Also, it is not certain whether the lack of paternal imprinting may influence the utility of these stem cells (Green 2008a). Parthenogenesis is also implicated in moral, ethical and religious issues. A parthenogenetic embryo has some capacity for development and there are some who might consider an artificially stimulated egg as equivalent to a human embryo. Moreover, some pious people may find this as a delicate matter that conjures subjects from religious traditions in which virgin birth is portrayed.24 Unless there is a certainty that a dividing parthenogenetically activated egg is not a human embryo (particularly for people who adopt the second view that the embryo is equal to an adult human being), arguably there is a moral and ethical duty to prevent research involving human parthenotes. Reasonable doubt must be ruled out before a research on parthenotes can be legitimate.
Stem Cell Research that Do Not Involve the Use of Embryos Adult Stem Cells The procedure that involves the use of adult stem cells has been performed for decades for a variety of purposes such as bone marrow-derived stem cell transplants. There are some adult stem cells that could be used for therapeutic purposes. These cells can be derived from living or deceased, adults, children and even from fetal tissue; the word ‘adult’ stem cells indicate that these cells are not of embryonic origin, although they are not necessary from mature adults only. Hence, the term could be misleading. Arguments on the relative value of embryonic and adult stem cell research have been at the core of ethical debates. It is frequently argued that only adult stem cell research should be pursued but not HESC research as adult stem cell research has not only its medical potential but also avoids serious ethical dilemma. As mentioned, embryonic stem cells are relatively easy to identify and grow. In comparison, adult stem cells are difficult to isolate 23 24
Report of the Committee of Inquiry into Human Fertilisation and Embryology (Warnock Report) (1984). Ibid.
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as they are inconspicuous, hidden deep in tissues and are present only in small numbers. Furthermore, adult stem cells are not found in all tissues. Also, very importantly, adult stem cells are multipotent and not pluripotent; thus, they can only give rise to some types of cells and are not as flexible as pluripotent stem cells. For instance, blood stem cells only result in other types of blood cells and nerve stem cells can only make various kinds of brain cells. Embryonic stem cells are more flexible than adult stem cells as they are pluripotent as in they have the potential to make every cell type in the body whereas adult stem cells are multipotent and produce a limited number of cell types. It is not likely that they alone could be used to make complex organs such as the heart or kidney. Adult stem cell research is often assumed to be an ethically pure alternative to HESC research but this research is not entirely free of its set of ethical issues. As mentioned, the term ‘adult’ stem cells is a misnomer and newly aborted foetuses are also a source of adult stem cells. Neural adult stem cell research has been conducted using stem cells extracted from the central nervous systems of foetuses. Compared to embryonic stem cells, using cells from foetuses is, even more, contentious given the more advanced stage of development. Other ethical and regulatory concerns arise, including those that relate to ‘stem cell tourism’. This is where desperate patients, especially the very ill, who live in countries where stem cell-based medical treatments are not available, travel to other nations to seek such therapies. Some patients are prepared to go and pay a high price to try these treatments. Some of them involve the use of the patients’ stem cells. It is noted that these therapies are at the experimental stage. At present, only a very limited number of stem cellbased therapies are proven to be clinically effective for medical conditions like haematopoietic stem cell transplants for leukemia and epithelial stem cell-based treatments for corneal disorders and burns. Beyond this limited scope, there have been reports of baseless claims of cures, charlatans and adverse medical events including deaths. These stem cell-based treatments are available in different countries, in both developed and developing countries. Companies offering these services advertise the procedures on websites, YouTube and blogs. Many of them are unregulated with no oversight and transparency; after all, adult stem cells are the patients’ cells returned to their bodies. Patients in need of a new windpipe can receive an artificial trachea grown from mesenchymal stem cells taken out from their bone marrow, although the safety implications are not well understood (Elliot et al. 2012). Using similar techniques, scientists are also working on regenerating bladders using stem cells harvested from a patient’s bone marrow (Sharma et al. 2010). Adult stem research is crucial and should continue to be pursued. Induced Pluripotent Stem Cells/Somatic Cell Dedifferentiation Induced pluripotent stem cells (IPS cells) are the most conspicuous alternative source of stem cells. These are adult cells, such as skin cells, which are reprogrammed into a pluripotent embryonic-like state. Unlike adult stem cells, IPS cells may have the same efficacy as embryonic stem cells; these dedifferentiated cells demonstrate basic properties of self-renewal and they have the capability to develop into different cell types. They can be procured without generating or destroying any human embryos. A team of scientists at Kyoto University led by Shinya Yamanaka made this innovative groundbreaking discovery (Takahashi and Yamanaka 2006). They reported that they had managed to reprogram adult mouse skin cells, taken from the tail tip, to behave like embryonic stem cells, without creating the embryo. Four genes (Oct3/4,
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SOX2, c-Myc and Klf4) were used. These genes were inserted into a fibroblast (cultured skin cells) using virus vectors to transport them and they then override the adult state and transform the cells into embryonic-like cells. A year later, the technique was shown to work with human cells (Yu et al. 1917). Both Yamanaka’s team and James Thomson’s group reported the generation of IPS cells from human fibroblasts. Thomson used a mix of a different set of genes in the reprogramming. The IPS technology is promising as these cells appear to resolve some fundamental problems. First, unlike HESC research, no human embryos are created and destroyed in the formation and use of IPS cells. Next, like the embryos created by SCNT, IPS technology offers a solution to the problem of rejection as IPS cells could be dedifferentiated from the somatic cells of the patient and would have the same genome as the patient and thus be compatible with his/her immune system. Moreover, unlike HESC research involving the use of excess IVF embryos, where consent needs to be obtained from the donor couple, no such difficulty arises. Finally, unlike SCNT, the IPS technique does not require the procurement of human eggs which can be a challenge to obtain; the hormonal treatments used in collecting eggs from women can lead to various health problems including ovarian hyperstimulation syndrome (OHSS). IPS cells are easily generated and thus they are available to scientists to study cell differentiation and compare healthy and diseased cells. Compared to SCNT, IPS cells are easier to use (Goldman 2008). Also, since the IPS cells share nuclear as well as mitochondrial DNA with the patient, they are considered to present less risk of immune rejection, whereas cells derived by SCNT carry only the same nuclear DNA. Shortly, IPS cells will be available for drug screening as well as testings, which previously have been tested only on animals (Shinnawi et al. 2015). Regenerative medicine is in the more distant future and a group has treated mice carrying the human gene for sickle-cell anaemia by providing them haematopoietic stem cells derived from those mice’s generepaired IPS (Goldman 2008). It has even been suggested that the IPS technique could end the debate over the highly contentious HESC research. Interestingly, there are scientists, including eminent ones like Ian Wilmut (who led the first team to clone a mammal, Dolly, the sheep) (Blackman 2009) and James Thomson (who led the first group to derive human embryonic stem cells) (Baker 2009), who have decided to shift their research focus from embryonic stem cells to IPS cells (Holden and Vogel 2008). However, there are ethical issues unique to the use of IPS cells. The infinitely versatile cells can be induced to become gametes/reproductive cells, i.e. the IPS cells can be used to obtain both sperm and eggs. The scientists cross the sex cells in a laboratory dish to conduct studies on aspects of human genetics (Cyranoski 2014). This method could restore reproductive capability to cancer patients who have become infertile during chemotherapy. Eggs and sperm could be obtained from a male and be used in the in vitro fertilisation process and the resulting embryo would not be an identical clone. However, some would argue that it is unacceptable to use any cells in research to develop a new life. There are uncertainties surrounding the long-term consequences of reproduction using iPSC-derived sex cells that include risks/harm for children created using these sex cells. They are exposed to risks that they had no opportunity to consent to. The arguments above illustrate that there are various concerns and uncertainties with the use of IPS cells on humans. While this technique does not require human embryos, yet there are ethical and scientific hurdles. Currently, their therapeutic value is limited and the emergence of IPS technology does not obviate the need for HESC research.
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Conclusion The creative works of these ingenious scientists are actually impressive and commendable. However, while it is often assumed that the various sources of stem cells which do not involve the destruction of human embryos proposed for research and therapy are entirely free from ethical issues, some of them are laden with moral baggage to varying extents as explored in this paper. The divergent views which appear in Anglo-Western literature will mean that there are people who either oppose (i.e. those who adopt view two) or ambivalent (i.e. those who adopt view three) about research that involve the use of human embryos. Instead of avoiding moral controversy entirely, scientists embarking on stem cell alternatives are trading one set of ethical concerns for another. Moreover, some of these techniques raise scientific challenges. The different sub-areas of stem cell research, whether embryonic or stem cell alternatives, cannot be dogmatically categorised into contentious and non-contentious. The ethical acceptability of a particular scientific technique is a matter of moral judgment. These issues impinge on public policy and the various ethical considerations should bear on the decisions of policymakers. In some nations, such as United Kingdom (UK) and Australia, the highly controversial HESC research is stringently regulated. The effective regulatory framework will promote ethical conduct, allays public concerns and ensures transparency and accountability. With tight regulation through oversight agencies, it is argued that all types of stem cell research, especially adult stem cells, IPS and the contentious HESC research, should be conducted simultaneously. Much more work is necessary to determine the best route to the clinic. As the various types of stem cell research are inter-connected, discoveries in one sub-area provide lessons for the others which will increase the overall knowledge and understanding of stem cell science. Over time, scientists continue to improve and attempt to perfect theirs and other scientists’ techniques. And the hope is that the result will lead to the discovery of new and improved stateof-art therapies for patients. As Hyun said, ‘the caravan of stem cell science, as the metaphor suggests, is composed of many parts and yet progresses together as a whole’ (Hyun 2011). Acknowledgements
The author wishes to thank the editor and reviewers for their comments.
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