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The
Walter C. Randall Lecture: |
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| I was privileged to give the Walter
C. Randall Lecture to the American Physiological Society at the IUPS/APS
meeting in San Diego in April of this year, and the first part of that
lecture was published in the last issue of
The Physiologist. In that issue, I argued that medical research is an inherently ethical pursuit. We can all be proud that we work in medical research. We try to solve problems so that healthy people remain healthy, and ill people become better. Sometimes we have to accept that a disease is too damaging to a person, and a situation is beyond help, but we always try, through research, to improve the state of humankind. Most of the time, our choices in research are simple. If we cannot solve a problem, it is because we do not have the resources, or the technology, or the skills. Occasionally, however, trying to solve a problem raises ethical issues. Simple ethical issues are solved equally easily—if something is thought to be unethical, and there are no benefits to be gained, just don’t do it! Problems arise, however, when there are conflicts between different acceptable ethical principles. Usually the conflict is between wanting to commence or continue research that might help to treat or prevent a disease, but by so doing perhaps cause harm to another individual, or work in a way that appears to lack justice or to disrespect a person’s autonomy. The conflict is magnified if the research takes place in a field that is moving very quickly. Embryo and stem cell research poses just such problems to our medical research community. Until Dolly was cloned, there was a delightful simplicity to defining the beginning of a new life. Mammalian reproduction, it was thought, began when a sperm hit an egg. This is the clear moment in social time that links sex, love and a baby. It is a very significant moment biologically, as it represents the start of a new entity that can implant in a womb and develop to give a fetus and eventually a baby. It meets the third criterion of identity, a new genetic person different from its parents owing to DNA meiosis followed by recombination, scrambling the parents’ genomes into a new and unique genome. Most people believe that fertilization is at least one key moment, and many brought up in the Christian traditions (particularly Roman Catholics) would propose it is the key moment. In scientific terms, it combines three important features: social, genetic and biological individuality. Even those like myself who argue that we should accept a more gradual time scale for acquisition of the respect due to a living human being over the nine months of pregnancy respected the simplicity of fertilization as a key event. Dolly changed all that. Dolly demonstrated that any cell in the human body, not just an embryo created by fertilization, could, in principle, give rise to a baby if treated in a certain manner. It separated biological individuality from social and genetic individuality. A human cell in a Petri dish (a diploid somatic cell, in scientific terms) is due little if any respect, and is certainly not an embryo (though it has the potential to become an embryo). We kill our cells all the time, when we wash our hands or have a nosebleed or brush our teeth. Yet if that cell were to be treated and implanted so as to give a child by reproductive cloning, the child would be due respect as a person. When, in the absence of fertilization, the absence of a sperm or an egg, is that respect acquired? Stem cell research matters. While adult tissue contains stem cells, only very early stem cells, such as those obtained from embryos (ES cells), have maximum capacity to divide infinitely and give rise to all types of tissue. One way to obtain ES cells is from so-called surplus embryos, no longer needed after successful IVF pregnancies. However, this does not allow ES-equivalent cells to be made from those with multifactorial diseases such as diabetes or SLE, nor stem cells that are immunologically identical to a patient. An alternative way to obtain ES cells is to place a somatic cell nucleus into a human egg from which the genes have been removed. This somatic cell, created by nuclear transfer (SCNT), can be given an electric shock which allows it to develop with some embryo characteristics, and stem cells can be harvested from it. However, it is not an embryo, because there is no sperm, no genetic identity, no social context. It is only if it is placed in the medically prepared womb of a woman at an appropriate time that it has even a very small chance of developing into an embryo, a fetus and a baby. At present, most attempts at “Dolly cloning” (whether for reproduction in animals, or to obtain ES cells in humans) use an enucleated egg. However, it is already clear that it soon will be possible to derive mammalian clones without either eggs or sperm, by direct treatment of somatic cells. This blurs the boundary between embryo and somatic cell still further. Implantation is a better time to define the start of the existence of the “embryo deserving respect,” because it combines the intention to embark towards reproduction with the possibility that a baby will result without further laboratory intervention. We have lost the innocence of being able to offer a moment in time (fertilization) that marks the beginning of a new life. The stem cell made by nuclear transfer is just another somatic cell in culture, with the original diploid genome of the person from whom it was obtained. We need these stem cells to find new treatments for cystic fibrosis, ataxia, heart disease and cancer. The potential for stem cell research is great. At this time, we do not know which type of human stem cell will be most useful, ES or cord blood or adult. It is probable that some types of cells will be best for some purposes, others for different purposes. We need to achieve a consensus on the best way forward, starting with respect for all views and for the interests of everyone, including patients with the disorders under study. Everyone agrees that cloning people is unethical, because of the medical hazards and the loss of autonomy for the person cloned. There must be strict, internationally agreed rules to stop artificial cell constructs being put into the womb. However, it is also unethical to ignore opportunities to carry out research that could benefit many sick people. A cell from you or me in a lab dish is just that, and does not pose an ethical dilemma as long as it stays there! |
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