-Benfu LI, M.D. Professor of Department of Medical Ethics, Director of Division of Medical Ethics, Peking University Health Science Center (PUHSC), Peking University, Beijing, China
Stem cell research is one of focuses in life sciences. It was rated as No.1 of World Ten Great Technology Achievements by the American magazine Science in 1999, and again as one of World's Ten Great Technology Achievements in 2000. However, the disputes aroused by human embryo stem cells, especially cloning and human embryo research are the focus of much present argument. It is beneficial for the healthy development of human embryo stem cell research to explore its ethical disputes.
Stem cell is an early original cell with self-renewal, high multiplication and multilateral or unilateral polarization potential. There are totipotent, pluripotent and mono-potent stem cells. Totipotent stem cell is the stem cell, which could polarize into human body's 200 sorts of cell, constituting every tissue and organs, and finally grow into a whole body. A pluripotent stem cell is formed from totipotent stem cell's continual polarization, and has the potential of developing into many sorts of cells. However it loses the ability of growing into the whole body, such as cord blood and bone marrow hemopoietic stem cells, and so on. A mono-potent stem cell is from a pluripotent stem cells' continual development, and can only develop into one type or two closely interrelated types, such as stem cells of epithelium or muscle stem cells, etc.
To make a human embryo totipotent stem cell, combining with modern biomedical and engineering technology, it is possible to reforge human body's every tissues and organs, to repair or replace the pathological or decrepit tissues and organs. So that scientists could treat cancer, diabetes, cardiac muscle infarction, self-immunity disease, and some nerve diseases, etc. Combining with genetic treatment, scientists can also treat many genetic diseases. Therefore, scientists have done much explorative experiments, for instance, American scientist Thomson solved early embryo's dependency in vitro with a culture medium of G12 and G22, and cultivated fresh or frozen zygotes from 4-8 cells to blastocyst stage. After the inner cell group was separated, an embryo stem cell system was established generally. Meanwhile, John Hopkins University Scientist Gearhard's Group also got the totipotent embryo stem cell system with immortal potential from abortive embryo's genital stem cells. The researches established embryo stem cell systems, resolved stem cell's source, that's to say, it's unnecessary to always get stem cells from an embryo. The further research is how to directionally induce these cells into needed tissue cells and to carry through organ's three-dimensional formation. Scientists have done a series of analysis and attempts. For example, the Medical Science Institution of Shijiazhuang city of China and Henan Medical University did intracranial transplants with human embryo stem cell and achieve good curative effect in treatment of brain agenesis, which shows that inducement to needed cells has a good beginning. Formation of organs is a complicated three-dimensional process, therefore scientists did some experiments, such as Japanese scientists who put tretinoin into thousands of frog stem cells, the high concentration formed frog's ears, and low frog's eyes. And a professor of Japanese Xinzhou University transplanted the experimental rat's heart cell into ventral aorta and cultivated new rat's heart.
It's thus clear that ES cell research and its application to cell, tissues and organ has a bright future. The immunological rejection is still not resolved, but cloning human's embryo and extracting stem cell for auto-transplant could remove immunological rejection, and resolve the question of source of donor. In addition, ES cell research could improve scientists to understand human's complicated growth process and cause of diseases, congenital defects and cancer, change medical development and test many methods.
The source of human ES cells are usually from such ways as follows: embryonic tissue from abortion, leftover of IVF, which is donated by couple who suffer from infertility, by the way of IVF to make embryo with the donated gamete, cloning embryos by the technology of body cell nuclear transplantation and asexual reproduction.
Among the sources of human ES cell, there are a few disputes over using embryo tissue from abortion; secondly, embryos left by infertility treatment also arouse some disputes, but because embryos would be destroyed sooner or late, I think it is not serious. The third, and it is the greatest dispute, that is on ES cell researches and cloning human's embryo, because the both not only would destroy embryo, also the former makes producing embryos for aims other than making a person, and has also the danger of human cloning.
The focus of the dispute is: is embryo a life? A human being? Should it be respected? There are different answers. Those opponents think that embryo is life, even a person, the research will be blasphemous, trample life's dignity, and using clone human in research will lead to clone human. In addition, some western countries have been enacted laws to forbid to research with human embryo, for example, in 1985, the US Capitol Hill enacted a law to forbid using federal government's funds to research in that human embryo "be destroyed, abandoned or hurt, or hazarded to die";. In 1990, Germany carried into execution "Embryo Protection Law", to forbid research with human embryo. In 1990, British also passed an act to strictly limit research of human embryo, and count the research of clone human embryo illegal. However, different voices also become higher now. Heris, the speaker of British Freedom Democratic Party said: "one embryo of 14 days is not worth of our respect, and the greatest respect to human life is releasing thousands of suffers from cancer, Parkinson disease and organ transplants." Some scientists thought that only if the fertilized ovum does not grow in uterus, it would not become a whole unit, then, couldn't be called life. In April, 2000, 73 American famous scientists, including 61 Nobel winners, asked Capitol Hill to abrogate the bans of research of human embryo stem cell, and supply full supports to the stem cell research. Months from that, 100 British scientists and Nobel winners also jointly delivered in the Sunday Times Newspaper to appeal British government to give scientists more freedom in bioscience researches.
In both above arguments, some governments have noticed human ES cell's potential value to organ transplant and treatments, and some legal decisions are made. First, Japan counts on this technology as a good opportunity to overtake Europe and America in the fields of bio- science and biological technology, so in May, 2000, a law was made which listed conditional allowance to human ES cell research. In July, 2000, Australia Premier Congress decided to allow scientists to carry the research of extracting stem cell from the existing 70,000 frozen human embryos. On 22nd, Jan., 2001, British Parliament opened the green light for human ES cell research (Voting 212 approving and 92 opposed). Afterwards, French and Germany agreed to import human ES cells for medical research under strict controls.
Due to the restriction of ethics and laws, the governments still are very cautious to human stem cell research. Generally, therapeutic cloning is allowed, and productive cloning is not, and the clone experiments combining human and animals are also forbidden. Even though therapeutic cloning is allowed, it should accept strict examinations and supervises. On the 4th, Aug., 2000, the President Clinton declared that American government should allow to use government funds for the research of human ES cells. He thought that ES cell research would bring "incredible potential benefits". On the 9th Aug., the President delivered TV speech on human ES cell and was published in magazine of Science that allowed to use federal funds to do research of present stem cell systems, and he thought that these stem cells are from already existed embryos system , the question of living and death doesn't exist. The 23rd, Aug., the US NIH also passed the act of allowance to research of human ES cell. Later, on the 30th, July, 2001, American government delivered a statement to oppose clearly to apply human cloning technology to human reproduction, and it said that ethical problems by clone technology is not neglectable. Moreover, House of Representatives of U.S passed an act of forbidding any cloning of human embryo on the second day. In summary, the ethical disputes over human embryo stem cell research are not ended.
Most Chinese Scholars think that the embryo is human biological life, not human life. The embryo's value is not the same as another human. Therefore, they approve of human ES cell research for improving human's health, including using cloned embryos of less than 14 days. Meanwhile, they emphasis that the usage of clone embryo be controlled strictly, and oppose cloning humans. In addition, there exist hybrids of human cells and animal's ovum in cloning embryo research. Some think that it diminishes human dignity, and another think that it is only fundamental research and is not applied to human persons, so it has nothing to do with human's dignity.
A human embryo is a life after all, so strict management and prudent attitudes should be taken, including to establish an admittance system for institutions and ethical committee to review the research.. Ethical committee should interview according to following principles:
The principle of respecting embryos. Embryos have certain value, and should be respected. Even if just research, a human embryo should not be destroyed at will;
The principle of informed consent and confidentiality. The donors and users of gametes, body cells and embryo should be informed and consent, and keep the information secret;
The principle of safety and efficiency. While using human embryo stem cell as a therapy method, animal and human body experiments should be done beforehand. After making sure of it safety, it should be used on patients to avoid harm to them.
The principle of preventing commercialism. Donation is advocated, but any business of gamete, embryo and fetus tissue is forbidden.
1 Xuefei Wang, "Stem Cell Research", on Health News, 08-15-2000
2 Ruting Liu, "World Organ Transplant Congress Approves of Clone Organ", China Woman, 09-06-2000
3 Li Shen, "Reproducing Therapy: New Hope for Conquering Disease", Health Paper, 08-15-2001
4 Ying Xin, "Support Clone Human Forepart Embryo", Health Paper, 08-24-2000 5 Xiao Zhang, "Medical Revolution Or Ethical Crisis: Fireworks by British's Allowance to Clone Human Embryo", Guangming Daily, 08-21-2000
6 Hongyi Wang, Shucheng Zhang, "Totipotent Cell Reproduce Heart, Brain and Nephridium", Health News, 06-08-2000
7 Shusheng Xie, "Human Embryo Stem Cell Research's Breakthrough and Ethical Puzzles", Medicine and Philosophy, 2000, 21(6).
8 Yanguang Wang, "Human Embryo Stem Cell's Source and Ethical Reflection ", Medicine and Philosophy, 2002-23 (2), 7-10.
9 Shusheng Xie: "The President Bush's TV Speech on Human Embryo Stem Cell on the 9th, Aug., 2001" Medicine and Philosophy, 2002-23 (2), 11-12
Xiaomei Zhai, "Ehical Disputes on Human Stem Cell Research", Medicine and Philosophy, 2002-23 (2), 13-16.