Tissue transplant advance

Stem cells have the ability to develop into any type of cell in the body

The scientists who helped create Dolly the sheep clone say they have managed to turn cow skin into heart muscle in a move that could one day be used to create replacement tissues for transplant.

I believe it will be equally applicable to humans

Dr Ron James, PPL

The US subsidiary of PPL Therapeutics announced on Friday that its researchers had re-wound the genetic clock of skin cells to create "master" stem cells.

The reverted cells were then programmed to develop into functioning, beating heart cells in the laboratory. The research has major implications for the controversy over using human embryo clones to conduct research into new medical treatments.

It increases the chances of using adult stem cells, rather than those taken from embryos, to develop nerve tissue, heart muscle or even brain cells for transplant. Stem cells are progenitor cells with the ability to develop into other cell types that make up the human body.

Commercial secret

PPL Therapeutics is keeping full details of the technique used a secret for commercial reasons. But Dr Ron James, managing director of the Edinburgh-based biotech company, revealed the early findings of the work at a meeting of the British Fertility Society in London, UK.

Dolly was produced by scientists at PPL and the Roslin Institute, Scotland

"The results of this experiment give us confidence that the method we are developing as a source of stem cells is working and I believe it will be equally applicable to humans," said Dr James.

The news was welcomed by ethicists. Dr Donald Bruce, director of the Church of Scotland's Society, Religion and Technology Project, said: "This is an encouraging breakthrough in the search for replacement cells to treat serious diseases without the need to use human embryos.

"It's obviously still too early to say that this is the solution we've been looking for, but it is certainly a step in the right direction."

Embryo research

In the past, scientists have focused on embryonic stem cells in their search for new treatments because these are thought to be more flexible than adult stem cells.

But some religious and "pro-life" groups have condemned the use of embryos as immoral.

In January, the UK became the first country to allow the use of human embryos for stem cell research.

UK politicians voted to extend the scope of research done on human embryos beyond that covering just infertility problems. In so doing, they permitted by default a limited form of human cloning to be carried out as well.