US bioethics council suggests embryo stem cell alternatives

The US President's Council on Bioethics has published a report on alternatives to human embryonic stem cells (ES cells), which do not involve the destruction of embryos. The document, entitled 'Alternative sources of pluripotent stem cells', looks at ways of extending the number of cell-lines available to federally funded stem cell researchers, who are not permitted to work on ES cell lines created after 9 August 2001 - the date on which President Bush's policy on this issue came into effect. However, the findings of the report are controversial, and two of the three research scientists on the 18-member council have 'vigorously rejected' its recommendations.

Many scientists believe that research on human ES cells, which can grow into almost any type of body cell, could lead to new treatments for a range of diseases. However, such research is not permitted in many countries, since it necessarily involves the destruction of early human embryos. The report suggests four alternatives to ES cells (described as 'pluripotent'): stem cells from 'dead' embryos that have stopped growing and are discarded by fertility clinics, from reprogrammed adult body cells, from embryos that are not destroyed in the process, or stem cells from 'bioengineered embryo-like artefacts'. However, the report concludes that the latter two sources could still be 'ethically problematic'.

Council chairman Leon Kass said that it should not be beyond the ingenuity of scientists to devise ethically acceptable ways of doing research on stem cells. But dissenting council member Michael Gazzaniga, a cognitive scientist at Dartmouth College, said in a statement that the four proposals for making all-purpose human cells were 'high-risk gambles'. The other council member who rejected the findings, cell biologist Janet Rowley of the University of Chicago, said she found it 'totally baffling' that it was deemed ethically preferable to let healthy embryos dies rather than use them to help sick and dying patients.

One of the methods regarded as ethically acceptable by the council involves the use of embryos created using fertility treatments that have stopped dividing and growing, and can be regarded as dead. Although this often happens because some cells are damaged or have faulty genetic material, the council considers it possible that other cells could be salvaged and used to grow stem cells. It draws a parallel between this approach and the use of transplanted organs after a person's death. The second favoured method is to identify the factors that trigger cell division after a body cell nucleus has been transferred into an unfertilised egg (SCNT), and use these to convert adult body cells into stem cells.

The report concludes that 'it remains to be seen whether any of these proposals will succeed scientifically, and more discussion is surely required on some of the ethical issues we have identified'. Sean Tipton, of the American Society of Reproductive Medicine and the Coalition for the Advancement of Medical Research, agreed that 'you ought to pursue all the alternatives', adding 'but we think that scientific merit ought to drive those decisions'. Tipton also said that ES cell research is the ethical alternative, arguing that 'we think that medical ethics ought to apply to living patients with diseases, not just tissues in a lab'.