Of Mice and Men: Skin Cells, Stem Cells and Ethical Uncertainties

Abstract

The recent reports concerning the creation of live mice from induced pluripotent stem cells (iPSCs) suggest that it may be possible to overcome one of the many critical barriers to creating patient-specific stem cell therapies – the derivation of truly pluripotent cell lines through reprogramming [1–3]. Nevertheless, these reports raise some important issues that must be considered. First, the reports suggest that iPSCs behave like embryonic stem cells, but also that it will be possible to dramatically improve the efficiency of their derivation. It currently takes a considerable amount of time and resources to create iPSCs, which hampers their potential use in medicine. Furthermore, the mechanisms for enhancing the efficiency of iPSC derivation are unclear and there is no guarantee this approach will work in humans. In addition, while tetraploid complementation in a murine model is unlikely to be controversial, it would clearly be problematic to conduct similar experiments in humans. Second, the value of using iPSCs for therapeutic purposes depends heavily on the derivation method employed. The method described by Yamanaka that was used in these recent reports introduces genes known to be associated with the development of cancers [4]. While at least one of the iPSC-derived mice matured and reproduced naturally, long-term health effects remain unclear. Third, while some may use these findings to suggest that embryos may no longer need to be used for stem cell research, thus eliminating the predominant moral and policy conflicts regarding stem cell research, such a conclusion is likely to be premature. These experiments involved the creation of embryos, from which the live mice were successfully born. Paradoxically, this brings us full circle to the knotty questions related to the moral status of the embryo. Thus, while this scientific achievement is important, the scientific and medical community, along with the public, need to keep perspective. First, clear ethical oversight of this research should be in place, consistent with guidelines already suggested by major professional groups [101,102]. Second, it is unlikely that all questions related to embryos and stem cell research have been resolved. Third, reliable and efficient methods of deriving human iPSCs need to be carefully developed before attempting to use them for therapeutic purposes. Fourth, long-term experiments involving iPSCs will need to be conducted to help ensure their safety.