Gene therapy for Parkinson's disease

A team of US researchers has used gene therapy to successfully reverse Parkinson's disease-like symptoms in monkeys. The scientists, based at Rush Presbyterian-St Luke's Medical Centre in Chicago, published their findings in last week's Science. 'Our study suggests a new approach to forestall disease progression by delivering potent factors with effects that are both long-term and non-toxic' said Dr Jeffrey Kordower, head of the team.

Parkinson's disease, which affects around 120,000 people in the UK, is caused by a gradual loss of cells in the area of the brain that controls movement. This results in tremors, muscle stiffness and eventual paralysis, even though the muscles themselves are unaffected. The symptoms are associated with a lack of dopamine, a brain communication chemical.

The scientists used a lentivirus 'vector' to deliver a gene that makes a protein, glial-derived neurotrophic factor (GDNF), to the monkey's brains. GDNF can promote the growth of dopamine-producing nerve cells in the laboratory, and also, it now seems, boost dopamine production in the brain. A group of older monkeys showing early signs of Parkinson's disease were given six injections of lenti-GDNF, and after three months, the symptoms had disappeared.

Dr Kordower hopes that human trials of the treatment could begin within five years, but says his main concern is that it could be too potent - excess dopamine can cause psychotic symptoms. 'What we need to do before we can go into humans is to have a gene that we could control' he said.