Chimeras, Hybrids, and Interspecies Research: Politics and Policymaking

Chapter 3. Cybrids, Cross-Species Embryo Transfer, and Transgenics

Chapter 3 Cybrids, Cross-Species Embryo Transfer, and Transgenics WHILE RESEARCHING HIS DAUGHTER’S MYSTERIOUS disease that brought with it seizures and kidney breakdown, James Reston Jr. noticed this headline in the New York Times: “Human-Cow Hybrid Cells Are Topic of Ethics Panel” (Reston 2006, 183). Looking for answers for his daughter, Reston responded with bafflement: “To this nonscientist, it seemed as if medical science was on the road to producing Minotaurs in the new millennium.” At issue was something more prosaic, but the headline highlighted the sensation that comes with novel interspecies prospects. This chapter looks at three topics that are part of policy deliberations but have not captured either the strong academic interest in chimeras or the distortions in the public imagination about hybrids. For organizational purposes, these three topics are grouped into a single chapter: creation of cybrids, cross-species transfer of embryos, and transgenics. CYbRIDS The article spotted by Reston on human-cow hybrid cells referred to the experimental use of animal eggs to study somatic cell nuclear transfer (SCNT) (cloning) techniques as a method for procuring ES cells. In this technique, somatic cell nuclei are transferred to enucleated eggs, and the eggs are activated via an electric or chemical charge. The entity begins cleaving, and when it reaches a certain stage, the cells aggregate to an inner cell mass that, for a short period of time, contains undifferentiated ES cells. The eventual clinical goal is to coax the derived cells to differentiate to whatever specialized cells the patient needs and then to transfer them to him or her. because the cells originated from the patient, they 77 78 Chapter 3 will share the same genome and be compatible, which will free the patient from requiring immunosuppressive drugs. More basic research is needed before many clinical trials stemming from this technique can commence. A significant hurdle for this research is the difficulty of obtaining human eggs. Might animal eggs be a substitute ? If so, they could be used to create entities from which ES cells might be derived. Variously called a “pseudohybrid,” “interspecies embryo ,” “cytoplasmic hybrid embryo,” “cybrid,” “interspecies cytoplasmic hybrid,” and “nuclear-cytoplasmic hybrid,” a term used informally in the United Kingdom will be adopted here: cybrid (U.K. House of Commons 2007, 6, 20). Cybrids are “embryos created by removing the nucleus of an animal egg and inserting the nucleus of an adult cell from a different individual (and possibly of a different species)” (U.K. Department of Health 2007b, glossary). The process of creating cybrids is informally called “interspecies SCNT” or iSCNT (Vogel 2006, 155). Using readily accessible animal eggs could speed studies geared to other ends as well, such as understanding the mechanisms behind diseases linked to defects in mitochondrial DNA (mtDNA) or developing methods for reprogramming gene expression (U.K. Department of Health 2007b, Appendix H. 3.5). Human eggs are generally in short supply for research. Although women may be motivated by feelings of altruism to donate eggs to couples trying to conceive, incentives to donate for research are less attractive, especially with compensation in doubt. Another source of eggs—those donated by women as part of their fertility care when they produce more eggs than they want to have fertilized—may not be sufficient because of poor quality that contributed to infertility in the first place (United Kingdom. Parliament 2007d). Although hyperstimulation and other aspects of the process are for the most part safe, they pose short- and long-term risks for human donors that may not be outweighed by benefits if only a small number of eggs are retrieved (Spar 2007, 1290; United Kingdom. Parliament 2007e). This is particularly the case in light of the large number of eggs needed to proceed systematically with the research. Some policy advisory groups have recommended against compensating egg donors beyond reimbursement for expenses (Spar 2007, 1290). Cybrids, Cross-Species Embryo Transfer, and Transgenics 79 They are concerned that undue inducements could undercut the voluntary nature of the donation. In South Korea where researchers claimed— fraudulently it turned out—to have derived human ES cells from embryos created through SCNT, some of the egg donors were students of the lead investigator and may have experienced inappropriate pressures to donate. Concerns are also expressed about undue inducement for women with low incomes and for those enrolled in colleges and universities. Policies at the California Institute for Regenerative Medicine originally forbade...