Scientists announce stem cell breakthrough

Scientists have succeeded in turning skin into heart muscle by re-winding the genetic clock in cells.

The breakthrough by a US subsidiary of British biotech company PPL Therapeutics has major implications for the controversy over the use of cloned human embryos.

It increases the chances of using adult stem cells, rather than those taken from embryos, to create replacement tissue in the laboratory.

Stem cells are unprogrammed pre-cursor cells with the ability to become different kinds of tissue.

Those found in early stage embryos can theoretically be made to differentiate into any type of cell in the body, opening up a vast new avenue of potential ways to repair damaged organs and treat incurable degenerative diseases such as Parkinson's.

Critics with ethical objections to the use of embryos for stem cell research have argued that adult stem cells could be employed instead.

However, despite some promising research into "re-programming" adult stem cells, they are much more limited than embryonic cells, usually having the power to become only one or two kinds of tissue.

The announcement by Dr Ron James, managing director of Edinburgh-based PPL Therapeutics, offers new hope that this might not remain the case.

Scientists at the company's wholly owned US subsidiary, PPL Therapeutics Inc., managed to revert fully formed skin cells from cattle back into undifferentiated stem cells. These were then chemically programmed to become functioning beating heart cells.

For commercial reasons, PPL Therapeutics is keeping details of the technique used a secret. But it involved inserting a "marker" gene into the skin cells that allowed the scientists to track their transformation first to stem cells and then heart cells.

Dr James revealed the early findings at a meeting of the British Fertility Society in London.