Editorials

Stem cell research

The UK government should sanction carefully regulated research

Later this month the UK parliament is scheduled to vote on recommendations on stem cell research made in a report by the chief medical officer, Liam Donaldson.¹ The leading recommendation is that research using human embryos should be permitted to allow exploration of the nature and therapeutic potential of stem cells. The outcome of the vote may have repercussions well outside the United Kingdom for there is considerable controversy, both in the United States and Europe, about this form of stem cell research.

Research on human embryos up to a limit of 14 days is already permitted in the United Kingdom, under the 1990 Human Fertilisation and Embryology Act, in five specific areas. These include infertility and pre-implantation diagnosis of genetic and chromosomal disorders. The chief medical officer's report proposes expanding the purposes for which human embryos may be used under the act, and it would cover research using stem cells derived by cell nuclear transfer as well as from "spare" embryos created during in vitro fertilisation procedures. Research would be permitted only under license from the Human Fertilisation and Embryology Authority, as is currently the case.

Extending the scope of research on human embryos does not on the face of it raise a fundamentally new ethical challenge. But it has put the spotlight back on this form of research. "A significant body of opinion is firmly opposed to any form of research involving embryos," Donaldson acknowledges, "because they believe that an embryo should be accorded full human status at the moment of its creation." What has generated fresh concern, however, is "therapeutic cloning," the popular but emotive name for cell nuclear transfer.

This technique entails removing the nucleus from a somatic cell and fusing it with a (donor) oocyte that has had its own nucleus removed. The cell is then stimulated to develop, and the stem cells are taken from the developing blastocyst. The advantage of this technique over deriving stem cells from "spare" embryos, umbilical cord blood, or aborted fetuses, is that the cells obtained are genetically identical to the donor and so rejection would be avoided.

Some believe, however, that sanctioning therapeutic cloning is a step too far. In a recent parliamentary debate the MP Ann Winterton said that "if we accept therapeutic cloning now it will lead on to reproductive cloning later." It is precisely because of this fear that the government, which has welcomed the Donaldson report, has said that it would introduce primary legislation to prohibit reproductive cloning.²

Over the past two years the therapeutic potential of stem cells has become more apparent, as a special issue of Science on stem cell research and ethics shows.³ Research, mostly in animals, has shown that stem cells can be stimulated to develop into a wide range of cell types. This has raised expectations that in the long term they may prove to be an effective regenerative therapy for a wide range of disorders including Parkinson's disease, Alzheimer's disease, type 2 diabetes, myocardial infarction, severe burns, and osteoporosis.

A raft of recent research showing that adult stem cells may also be stimulated to produce new cell lines has generated much interest. The ethical dilemmas would be resolved if adult stem cells derived from bone marrow and other sources could be used instead of stem cells from embryos. The problem is that it is not possible to obtain adult stem cells from most tissues, and expert groups agree with the independent scientific academy the Royal Society "that it will be at least a decade and very possibly a lot longer (possibly ever) before scientists will be able to overcome the hurdles blocking the therapeutic use of adult as opposed to embryonic stem cells."⁴

As MPs ponder their decision they are not short of advice. Clear statements on the rationale for stem cell research and the case for sanctioning therapeutic cloning have been made by the Medical Research Council, the Wellcome Trust, the Nuffield Council on Bioethics, the British Medical Association, and the Roslin Institute, as well as the Royal Society.^5-7 The European Group on Ethics in Science and New Technologies has taken a rather more cautionary stance. It recommends pursuing the research but states that "the creation of embryos by somatic cell nuclear transfer would be premature."⁸

As MPs weigh up the evidence and the ethical concerns it is important to bear in mind that these cut both ways. Arguments against therapeutic cloning must be set not only against the scientific case for it but against patients' interests too. In the United States a coalition of groups of patients has argued for public funding for such research. Their view is encapsulated by the recent statement made by the UK Parkinson's Disease Society that "stem cell research involving therapeutic cloning is justified to improve patients' lives."⁹

To argue, as a recent editorial in Nature has done, that new technologies using adult stem cells might ultimately replace therapeutic cloning is valid.¹⁰ But the current case for permitting tightly regulated research on embryonic stem cells, in addition to adult stem cells, is persuasive. Donaldson's well reasoned recommendations should be accepted.

Tessa Richards, associate editor. 

BMJtrichards{at}bmj.com