THE news that it may be possible to develop stem-cell therapies for illnesses such as Parkinson's and diabetes without first having to destroy human embryos is very encouraging. Two teams of researchers, in the United States and Japan, have reported success in genetically reprogramming adult skin cells as stem cells with properties similar to those from human embryos. From that point it should be possible to take a new approach to stem cell therapy which would avoid the ethical and practical difficulties that have delayed progress until now. Research has been held back by a shortage of embryos and also by ethical reservations about their destruction, especially in the United States; in Britain research is permitted under licence. Although the reports from the two teams working independently have been welcomed by other scientists engaged in this field, there have also been words of caution about expecting too much too soon. The first applications are likely to be in research into genetic disease. But Professor Ian Wilmut, who led the team that cloned Dolly the Sheep, envisaged a time when stem cells could be used to form any tissue from a small sample taken from any us.
The ultimate objective is presumably for stocks of stem cells that can he held ready to turn into any of the 200 or more tissue types in the body that might need replacement.