Test of benefits for mice and men

Stem-cell research is the subject of intense media interest for two reasons: the huge potential it offers to provide treatments for a variety of human diseases and the ethical dilemmas some feel those treatments may involve. Eve Herold is a science and health journalist who has witnessed at first hand many of the recent developments in this unfolding research. In Stem Cell Wars , she offers a detailed account of these events set against an account of the underlying biology and the potential clinical benefits.

It was recognised many years ago that there are cells in our bodies that have the potential to multiply and supply replacements for cells that have died. This is because these stem cells can divide either to produce more cells like themselves or to form other types of cell. The stem cells with the potential to form the greatest variety of other types of cell are obtained from very early stages of development. These are the embryo stem cells, and their immense potential can be shown in the mouse. If stem cells from one mouse embryo are introduced into another embryo, they will contribute to all the different tissues of the developing mouse. If the cells from a strain of mouse that has a white coat are introduced into an embryo of a black strain, the resulting offspring will be a mixture of white and black. These offspring are said to be chimeras, meaning that they are derived from the cells of two embryos. This simple test reveals that the cells have the ability to form all the different tissues of an adult, and it is this astonishing ability that gives them their great value in research and potentially in therapy. Such cells were first isolated from human embryos in 1998 by Jamie Thomson and his colleagues working in Madison, Wisconsin.

By contrast, stem cells taken from later stages of development have a more limited ability to form different tissues. Until recently, it was believed that stem cells obtained from one tissue had the ability to form only other cells for the same tissue. However, that the restriction may not be so complete. There is evidence, for example, that cells from bone marrow may be able to form cells from other tissues, although this is hotly debated.

One striking way to make that change is through cloning. The birth of Dolly, the cloned sheep, showed that if the genetic information from an adult cell is introduced into an unfertilised egg from which the genetic information has been removed, the resulting embryo will sometimes have the ability to develop normally. Stem cells derived from such an embryo would have the inherited characteristics of the donor of the genetic information.

It was in this way that Hwang Woo-Suk, a Korean professor, proposed to provide patient-specific cells for use in treating human disease.

Others have recognised that stem cells could be used to study any disease that the person had inherited, such as motor neuron disease or cancer. This approach might be used to identify new drugs to prevent or treat the disease in question. Many of the diseases and conditions that cause painful and lingering deaths and that at present have no effective treatment might one day be treated through research with stem cells. These include several neurodegenerative diseases and injuries to the spinal cord.

In these circumstances, it is only to be expected that such patients see new grounds for hope with successive announcements of progress toward potential treatments. Even if they know that the treatment will come too late to be of value to them, at least they can expect that an effective treatment will be available for future generations including, in the case of inherited diseases, any of their children who inherit the same disease.

They step forward willingly to take part in clinical trials, for everyone's benefit.

Imagine, then, the horror of hearing that the leader of your country proposes to ban the use of public funds to support research in a key area of stem-cell research - for this is the policy that President George W.

Bush announced in August 2001. His ban on the use of federal funds to produce new stem-cell lines from human embryos or to allow research on new lines dramatically limited academic research in the US, although companies are free to use their own funds as they wish, and several states, including California and Connecticut, have provided funds.

This policy and its implications are well known, it is much less well known that Bush took even greater exception to the use of nuclear transfer. As Herold makes clear, his Administration acted within the US and globally to try to completely prevent its use. Whereas the UK Government prohibited the production of children by nuclear transfer but allowed production of stem cells from cloned embryos for research, the Bush Administration supported a policy of banning human nuclear transfer for any purpose. However, a stalemate within Congress has made it impossible to pass any law to this effect. The US also sought to get a United Nations treaty to ban all human cloning. It appears that developing countries were told that receipt of any future aid would depend on their voting with the US to prohibit all human cloning. Leading the campaign against this policy was Bernie Siegel, a then little-known Florida lawyer. Siegel led a campaign at the UN to prohibit reproductive cloning while at the same time allowing production of cells by cloning, to study and perhaps treat disease.

The UN, however, could not come to any agreement. Siegel founded an organisation now known as the Genetics Policy Institute to campaign for stem-cell research. Herold is director of public policy research and education of the institute, which she joined after she had spent five years as director of public education for the Stem Cell Research Foundation.

In those capacities, she has witnessed many of the events she describes.

She visited Hwang in Korea and was there at the time of his downfall. It is from this vantage point that she writes this detailed account. As part of her work, Herold has come into contact with most of the people involved.

She has met many who might benefit from stem-cell research and describes the circumstances of some of them. She speaks to Congressmen and has made presentations to them. She has written an exciting, rapidly moving account of the events associated with stem-cell research.

Ian Wilmut is director, Scottish Centre for Regenerative Medicine, Edinburgh University.