Biological Engineering cannot replace rational resolution of ethical debate

It may be a healthy sign in the stem cell technological and ethical debate that we are getting round to the situation of considering just how many angels may dance on the head of a pin. In my opinion, the religious, political, ethical and moral dilemmas  which have been raised by the advances of embryological technologies and their application to medicine are not solved by technical workarounds.

In fact, the elaboration of technological ripostes to the medico-ethical debates about human embryonic stem cells (ES cells) only further highlights the need for a truer understanding of the biological realities by an informed public, and an understanding of the root causes of public disquiet by scientists - but not necessarily acceptance or acquiescence.

Two recent reports highlight this, both from America, and both using mouse embryos to derive ES cells in a manner designed to demonstrate potential methods for avoiding current objections to using embryos for the derivation of human ES cells. Perhaps these reports of science masquerading as ethical solutions to dilemmas which arise from other belief systems will serve to highlight the need for continued, reasoned debate and moderation of extreme dogma, be it political or religious.

The first is a publication from authors at the company Advanced Cell Technology in Massachusetts, together with researchers from the University of Wisconsin. They report making lines of mouse ES cells by separating a single cell from a very early mouse embryo. The embryo was then returned to the uterus of another mouse and allowed to continue to develop.  Some of these embryos gave rise to healthy adult mice. These results are totally unsurprising, because it has been known since 1989 that it is possible to isolate mouse ES cells from individual cells of an eight cell embryo. A recent publication has also recently revisited these results and carefully reconfirmed them. It has also been known, for a very long time, that it is possible to remove or kill a few cells in an early embryo without preventing normal development. This is now used in the technique of PGD, undertaken for serious genetically inherited diseases. Here, a single cell is removed from an eight or 16 cell human IVF embryo in order to be able to test for genetic abnormalities,  and choose healthy embryos for reimplantation. The present authors put the two technologies together for mouse embryos, and suggest that this is a demonstration of the way forward for making human ES cells without deliberately destroying a potentially viable human embryo.

The second publication from two eminent scientists at the Whitehead Institute also seeks to provide demonstration in mice of a method for making human ES cells without a viable embryo.  In this case, the embryo is produced by the 'cloning' method of cell nuclear transplantation from an adult cell into an egg cell. This transplantation results in the development of an early embryo that now has the genetics of the adult donor cell. This would therefore potentially provide matched cells for transplantation into the individual who had donated the original adult cell. This is a procedure sometimes termed therapeutic cloning. Objections to using this technique for humans centre around the fact that the embryo is theoretically - if not practicably - a human clone and might be able to develop in a host uterus. Making sure that the embryo is genetically incapable of development has been proposed as a technical fix for this ethical and regulatory hurdle. Alexander Meissner and Rudi Jaenisch have put a transgene into the donor cell which interferes with a gene necessary for early embryo implantation. This prevents the nuclear transfer embryo from being able to develop - it is non-viable as an embryo.  They have also cleverly engineered it so that this Trojan horse can be removed again at any time.

This is a scientific tour de force, but in the correct and appropriate regulatory environment would be quite unnecessary.