Human stem cells could one day provide us with a 'repair kit' for our bodies. Health Editor Barry Nelson met North-East scientists who are working in this fascinating area of research

A team of North-East scientists are optimistic that their research into stem cells will lead to revolutionary therapies which will benefit mankind.

Heard it all before? Of course you have. But it might surprise you that on this occasion, the North-East scientists in question are not based at Newcastle's high-profile and futuristic Centre For Life but in a science park on the outskirts of Durham City.

Arguably guilty of hiding their light under the proverbial bushel, the Durham University stem cell researchers have been persuaded to come out from under cover.

Indeed, this is the first time that the Durham team have revealed the progress they are making in one of the most promising areas of medical research.

Despite his obvious satisfaction at avoiding the limelight for some years, Professor Colin Jahoda, with his eye-catching shock of long white hair and soft Scottish accent, has already felt the full glare of publicity.

The professor of stem cell and developmental biology hit the headlines back in 1999 when he demonstrated a new hair transplantation technique which seemed to hold out the prospect of a cure for baldness.

His bizarre experiment - which involved his wife growing a tuft of his transplanted hair on her arm - showed it was possible to transplant selected cells from the base of a single hair root.

Crucially, unlike conventional tissue transplants, this technique meant that the host's body did not reject the donated material.

Samples of skin taken from Dr Jahoda's scalp containing hair follicle cells were implanted into a tiny nick made in his wife's forearm.

The theory was that the cells in the follicle root would 'talk' to the surrounding skin cells and produce new hair.

Sure enough, hair which was clearly thicker and stronger than normal arm hair sprouted on Dr Amanda Reyolds' arm. Tests carried out by colleagues at Columbia University in New York confirmed that the new hair came from Prof Yahoda and not his wife.

While the research, published in the flagship science magazine, Nature, attracted international publicity about 'a cure for baldness' and triggered a commercial race to find a way of applying the technique, Prof Yahoda is more interested in the bigger picture.

The 'hairy arm' experiment showed that one adult cell type can give instructions to another to create a more complex structure. In Prof Yahoda's view - backed in 2004 by a £290,000 research grant from the Biotechnology and Biological Sciences Research Council and £314,000 from the Medical Research Council - the principle of hair follicle cell transplantation could open the way to new areas of tissue engineering.

Specifically, the new approach could lead to new ways of healing wounds by encouraging rapid skin growth.

Unlike their counterparts in Newcastle, who are pursuing the glamorous route of embryonic stem cell research, Prof Jahoda and his colleagues are more interested in using adult stem cells.

There is growing international interest in the possibility of using adult stem cells - which do not have some of the loaded ethical issues surrounding embryonic stem cells - to produce new therapies.

Stem cells have the unique ability, when stimulated, to renew themselves and give rise to other specialised cells. This gives them the potential to repair or replace tissues and organs damaged by disease or disability.

Two years ago, a seriously ill British heart patient, Ian Rosenberg, revived after doctors in Germany injected stem cells into his heart to try to repair damaged tissue.

Impressed by the results, Mr Rosenberg has set up a charity which is sponsoring research at Barts and the London NHS Trust to determine whether adult stem cells taken from bone marrow can repair damaged heart muscle. This summer, Barts launched a trial to see whether heart diseases can be treated by using a patient's own stem cells. Durham University scientists have been working in this field for quite a few years and are well placed to make significant progress, according to Prof Jahoda.

"In principle, embryonic stem cells can become any cell that you want them to. With adult or mature stem cells, we think their ability to become different cells is more limited. Having said that, therapies using adult stem cells from blood, skin and bone marrow are already being tried out around the world," adds Prof Jahoda, who stresses that the Durham team work very closely with colleagues at Newcastle University. "The trick is to persuade stem cells to develop in the way you want them to."

We have certainly come a long way in a relatively short time. "It used to be thought that cells were fixed in stone. Once a cell was a muscle cell or a blood cell, it could not be changed or reprogrammed. We now know that they are malleable and can be changed. There is far more flexibility than we expected," says Prof Jahoda.

Much of the research is laboratory based and Prof Jahoda is looking forward to the planned expansion of research facilities at the James Cook University Hospital in Middlesbrough, so that doctors with an interest in stem cell research will have access to suitable laboratories.

So far as Prof Jahoda's stem cell colleagues are concerned, the focus is still on the basic biology, trying to understand how cells are made and how they are controlled and programmed.

But the possibilities are apparently endless. "There are already some therapies from cells in blood and skin which are being used with patients. That is already working. What is more difficult is trying to grow something like a brain or nerve cell," says Prof Jahoda.

"We may be able to grow nerve cells in a dish but what makes it more difficult is the fact that there are many different types of nerve cells. A big part is stopping inappropriate growth, to prevent you getting the wrong type of cells."

A lot of the experimental therapies being attempted around the world are based on the theory that cells communicate with each other.

"What they are hoping is that the local environment will 'talk' to the transplanted cells and get them to function in the way the scientists want," says Prof Jahoda.

The approach at Durham is more fundamental.

"We are trying to understand the mechanisms which would determine why a stem cell would become a certain kind of nerve cell."

While the emphasis is on basic research, Prof Jahoda says the Durham team are moving into a "transitional" phase which should mean that potential therapies could be approved.

"One of the problems facing us is that what may be straightforward in a test tube may be far more complex when the cells are put into a human body. You have to hope it will behave in a predictable and safe way."

Despite the difficulties, Prof Jahoda is optimistic about the future.

"It is a very promising area of research. I would say that, hopefully, in five years, we should be able to start clinical trials with patients.