Cloned stem cells successful in treating Parkinson's disease

Scientists in the U.S. have had success in treating Parkinson's disease in mice by using cloned stem cells.

The scientists say their research provides the best evidence to date that the disease can be treated with the technique and could eventually help people with the condition.

The researchers from Memorial Sloan-Kettering Cancer Centre in New York, say this is the first time animals have been successfully treated with their own cloned cells and the results are both exciting and promising.

With Parkinson's disease, nerve cells in the part of the brain that controls muscle movement either die or become impaired.

These are the cells which normally produce an important chemical known as dopamine, which enables the body's muscles to function in a smooth, co-ordinated manner.

The scientists say the research demonstrates that it may be possible to create a person's own embryonic stem cells to treat their Parkinson's disease.

Therapeutic cloning involves the nucleus of a cell being inserted into an egg where the nucleus has been removed; the cell then develops into an embryo from which stem cells can be harvested and used as a treatment.

For the research ordinary stem cells were taken from the tails of the mice and developed into the missing nerve cells in Parkinson's disease - the dopamine-producing neurons - and it was found that mice who received the neurons derived from their own clones showed significant signs of improvement.

However when the neurons were grafted into mice that did not genetically match the transplanted cells, the cells did not survive and the mice did not recover.

The researchers say the therapy is promising and exciting because, as the cells originally came from the animal that was ill, they were not rejected by its immune system.

The use of stem cell therapy for Parkinson's disease is being pursued by scientists because it allows the replacement of the dead dopamine-producing nerve cells with new, healthy cells, which should in turn restore the supply of dopamine within the brain and allow it to work normally again.

However experts say producing nerve cells which are able to survive after transplantation has been a challenge.

They say stem cell therapy offers hope for repairing the brain in people with Parkinson's, but more research is needed to guarantee safety and efficiency before the technique is tested on people with Parkinson's.

Stem cell experts have praised the research which they say shows therapeutic cloning could be beneficial.

Stem cells are the master cells of the body and embryonic stem cells are the key cells from which other cells and tissue are derived.

Stem cell researchers live in hope that ultimately a small piece of skin will be able to be taken, from which embryonic stem cells can be grown for personal, tailor-made medical treatments.

Cloning technology remains a controversial issue and therapeutic cloning to make human embryonic stem cells, or to create human embryos for this purpose, presents in particular ethical problems.

The research is published in the journal Nature Medicine.