Published on October 24, 2007
Slide1: The Eighth Asian Bioethics Conference March 19-23, 2007, Bangkok, Thailand Farzaneh Zahedi, MD Researcher of Tehran University of Medical Sciences : Bagher Larijani, MD Professor of Tehran University of Medical Sciences Farzaneh Zahedi, MD Researcher of Tehran University of Medical Sciences Medical Ethics and History of Medicine Research Centre, & Endocrinology and Metabolism Research Centre, Tehran University of Medical Sciences Slide3: The discovery of Embryonic Stem Cells (ESCs) in the 1980s suggested therapeutic approaches to chronic and incurable diseases. Using ESCs are surrounded by a number of ethical controversies. POTENTIAL APPLICATIONS: POTENTIAL APPLICATIONS The most important application of hES cells is clinically in transplantation and regenerative medicine. POTENTIAL APPLICATIONS: POTENTIAL APPLICATIONS NATURE BIOTECHNOLOGY 1999; 17: 1173 APPLICATIONS IN RESEARCH: APPLICATIONS IN RESEARCH Models of human diseases The pharmaceutical research Human developmental biology Gene therapy EMBRYONIC STEM CELL: EMBRYONIC STEM CELL Embryonic stem (ES) cells are derived from the inner cell mass of a blastocyst. The blastocyst forms at approximately 4 or 5 days after fertilization and contains from 64 to several hundred cells organized in an outer shell, the trophectoderm, and a collection of polarized inner cells termed the inner cell mass (ICM). J Clin Invest, Vol.114, No.9, 2004, pp. 1184-1186 PLURIPOTENCY: PLURIPOTENCY Stem cells retain the ability to differentiate into cells and tissues from all 3 germ layers (endoderm, mesoderm, and ectoderm). But, these cells cannot form the other ‘extra- embryonic’ tissues necessary for complete development, such as placenta and membranes, therefore they cannot give rise to a complete new individual. Human Reproduction, Vol.18, No.4, 2003, pp. 672-682 The Journal of Urology, Vol.170, 2003, pp. 2453-2458 Disadvantages of ESCs: Disadvantages of ESCs Cancer and Tumors : the potential of introducing cancer into patients because of rapid growth of embryonic stem cells Tissue Rejection Genetic Abnormalities High Failure Rate & Cost: Hundreds of thousands to millions of stem cell lines would be required to treat the majority of patients. CLONING: CLONING An alternative method of deriving human ESCs is somatic cell nuclear transfer (SCNT), or cloning . Dolly 1997-2003 SCNT across species is an important challenge. Slide12: Removing the maternal nucleus before nuclear transfer Nuclear transfer embryo about to be activated (Roslin Institute http://www.roslin.ac.uk) ADVANTAGES OF CLONING: ADVANTAGES OF CLONING No rejection, “Perfect match” Stem cells produced by therapeutic cloning are genetically similar to the cells of the individual who donated the nucleus, and thus avoid problems of rejection. The Journal of Clinical Investing , Vol.14, No.10, 2004, pp. 1364-1370 Journal of Medicine and philosophy, Vol.27, No.3, 2002. pp. 297-317 The New England Journal of Medicine, Vol.346, No.20, 2002, pp. 1576-1579 DISADVANTAGES OF CLONING Not Enough Human Eggs Cloning damages DNA Advantages/Disadvantages: Advantages/Disadvantages Slide15: KEY ETHICAL ISSUES Moral status of human embryo The creation of embryos only for research purposes Exploitation of women to obtain oocytes and commercialization of human eggs Resource Allocation Justice: Equitable distribution of the benefits is also important. Conflicts of Interests: financial interest of researchers Patenting of stem cell lines Animal/human hybrids … MAIN ETHICAL ISSUE: MAIN ETHICAL ISSUE Moral status of human embryo: The embryo is unavoidably destroyed during the process of ESCs harvesting. The question is whether the destruction of human embryos amounts to the killing of human beings. When does “human life” begin? The Status of the Embryo (cont.): The Status of the Embryo (cont.) One moral argument is that human ‘personhood’ begins at conception, or –as in cloning– at the genetic beginning. Based on this argument, the destruction of embryos for research cannot be justified. The Status of the Embryo (cont.): The Status of the Embryo (cont.) A different moral argument underlines that the moral status of embryos gradually increases with their development. Once they are born, they are entitled to enjoy full rights as human beings. Therefore, destruction of embryos can be justified to provide a treatment for patients. The Status of the Embryo (cont.): The Status of the Embryo (cont.) A third type of moral argument points out that certain milestones exist in embryonic development that change the status of embryos. For example: Ensoulment The primitive streak development at day 14, before three germ layers appear Slide20: Recent advances in scientific research and technological sophistication have raised totally new possibilities of defining birth and death; as key moments of life. All religions believe that usage of adult, placental, and umbilical stem cells is acceptable. Slide21: Controversy lies with idea of using embryonic stem cells and where life begins. There is substantial debate regarding at which specific stage dignity is conferred in development (conception, primitive streak development, implantation, ensoulment or birth). CHRISTIANITY: CHRISTIANITY Life begins at conception Killing embryo any time after conception is equivalent to killing a human being Christianity (cont.): Christianity (cont.) Although Roman Catholicism officially opposes human embryonic stem cell research, some Roman catholic moral theologians endorse it. Protestants have a wide range of views. Orthodox Church firmly reject any and all manipulation of human embryos for research purposes as inherently immoral and a fundamental violation of human life. JUDAISM: JUDAISM A fetus is not seen as being an ensouled person. Not only are the first forty days of conception considered 'like water' but also even in the last trimester, the fetus has a lesser moral status. A number of Jewish thinkers hold that the extracorporeal embryo, in the Petri dish or cry preserved, does not have standing in Jewish law and that it is justifiable to go forward with embryonic stem cell research. EASTERN RELIGIONS: EASTERN RELIGIONS Buddhism There is a notable diversity of views by Buddhists on cloning. Advocates: Cloning might be permissible under some understandings of Buddhism such as: - Central virtues of knowledge and compassion - Alleviate human suffering Opponents: Some primacy teachings of Buddhism can restrict such research; for instance: - Buddha prohibits infliction of violence or harm on sentient beings. ISLAM: ISLAM In opinion of most Muslim jurists, stem cell and cloning research, as great scientific events, would have advantages and limitations. Due to majority of Muslim reference decrees, according to inevitable consequences of reproductive cloning, it is prohibited. Larijani B, Zahedi F. Transplantation Proceedings 2004;36(10): 3188-3189. ISLAM: According to Islamic beliefs, the fetus undergoes a series of transformations beginning as an organism and becoming a human being. The fetus culminates in becoming a full human being when it is “ensouled” at 120 days (the end of the fourth month) from the moment of conception. ISLAM ISLAM: Given the Islamic teachings, the embryo, even in the first days of its existence, has the right to live and no one has the right to kill it; but the punishment of fetus eradication in the pre-ensoulment stages will be much less than abortion after ensoulment. ISLAM However, considering the potential therapeutic benefits of the procedure of stem cell research and cloning, destruction of the blastocyst and research into human ESCs could be justified. The Islamic Fiqh Council (1997): The conference was organized in Casablanca. A consensus was reached that: Cloning does not bring into question any Islamic belief in any way. Allah has established the system of cause-and-effect in the world. Cloning is a cause and only through Allah's Will it can produce the effect. The Islamic Fiqh Council (1997) Human Cloning: comments by political groups, religious authorities. http://www.religioustolerance.org/clo_reac.htm ISLAM: ISLAM Currently, stem cell research and cloning for therapeutic purposes is permissible with full consideration and all possible precautions in pre-ensoulment stages of fetus development. This is the consensus of Sunni and Shia Muslims; but only a minority of Sunni scholars are against it. - Larijani B, Zahedi F. Transplantation Proceedings 2004;36(10): 3188-3189. - Blood Cells, Molecules, and Diseases 2004; 32: 100-105. Slide31: A brief review of Islamic perspectives about reproductive and therapeutic cloning and stem cell research has been published in 2004. SCR and Cloning in Iran: Reproductive cloning is prohibited in Iran, however, embryonic stem cell research has been approved by the religious authorities and some projects have started. - Larijani B, Zahedi F. Transplantation Proceedings 2004;36(10): 3188-3189. - Office of the Supreme Leader, Ref # M/8/239001, February 5, 2003 SCR and Cloning in Iran SCR and Cloning in Iran (cont.): Iran was the 10th country in the world to produce, culture and freeze hES cells. Iranian scientists have established 6 human ESs lines since 2004. SCR and Cloning in Iran (cont.) Researchers at the Royan Institute were witness to the birth of the first cloned sheep born in Iran in 2006. SCR and Cloning in Iran (cont.): An emphasis on ethics has been voiced by medical and religious authorities in Iran in different decades. SCR and Cloning in Iran (cont.) The Specific National Ethical Guidelines for Biomedical Research were compiled in 2005 and communicated to medical universities and research centers in 2006. Larijani B, et al. Developing World Bioethics 2006; 6(2): 106–110. Larijani B, et al. Eastern Mediterranean Health Journal 2005; 11(5/6), 1061-1072. The Specific National Ethical Guidelines for Biomedical Research: The Specific National Ethical Guidelines for Biomedical Research Ethical Guidelines for Clinical Trial Ethical Guidelines for Research on Minors Ethical Guidelines for Genetic Research Ethical Guidelines for Gamete and Embryo Research Ethical Guidelines for Transplantation Research Ethical Guidelines for Research on Animals Slide36: Cooperation of scientists, ethicists, jurisprudents and lawyers is essential for establishing well-controlled, culturally-adapted systems in different countries. Conclusion (cont.): Conclusion (cont.) An ethical public policy in our pluralistic world has to respect diverse religious and cultural beliefs. Public education about the ethical and policy issues raised by stem cell research and its application is necessary.