A potential treatment for Parkinson's disease has greatly improved the condition of all five patients who took part in a trial, doctors said yesterday.
Although they said they could not yet announce a possible cure for one of the most common degenerative brain conditions, the doctors were optimistic the treatment could form the basis of an effective therapy within five years.
The pilot study involved the infusion of a growth-factor drug directly into the regions of the brain that degenerate in people suffering from Parkinson's. Some of the patients responded so well they learnt to laugh again and others regained their sense of smell, which typically is lost in the early stages of the disease.
Roger Nelson, one of the five guinea pigs in the trial, said the treatment had improved his ability to talk, walk, smile and laugh. "It is not something I expected to change that rapidly, but one of the things people with Parkinson's experience is a lost sense of smell," said Mr Nelson, 51, a former marketing director from Bristol.
"I had the operation on the Friday and by Sunday lunchtime I could smell. Very shortly after I noticed that I could be a bit more articulate. Speech had become fairly difficult," he said. "My wife passed a slightly risqué comment just after I got home from hospital and I burst out laughing, which I hadn't been able to do for several years.
"It has been progressive, little changes. We used to be quite keen bridge players and I got to the stage where I could not deal or shuffle the cards but now I can fan the cards and pick them out and play again," said Mr Nelson, who had the operation last May.
Steven Gill, the consultant neurosurgeon who treated the patients at the Frenchay hospital in Bristol, said that the drug, called glial derived neurotrophic factor (GDNF), stimulated cell growth naturally in the brain. The drug worked especially well on nerve cells that produced the neurotransmitter dopamine – a chemical messenger that was lacking in people with Parkinson's.
Symptoms of the disease range from slowness of movement, a shuffling gait and stiffness to tremors, depression and an impaired ability to think. Scientists have identified the cause as a degeneration of the dopamine-producing nerve cells in the dorsal putamen region of the brain.
Dr Gill said: "We can deliver [GDNF] very precisely to areas in the brain in the concentrations we need to cause recovery and we can control that very precisely.
"We thought that this drug would take some months or years to be effective [but] we found that really within a month or two patients were noticing significant changes."
Each patient was fitted with two pumps buried in the abdominal cavity, which supplied small and carefully controlled quantities of GDNF to the brain's dorsal putamen through pipes connected to catheters inserted through the skull.
A statement from the hospital said: "The preliminary results have shown marked improvement in the symptoms for all five patients. This is the first time that such improvement in a chronic neurological disease has occurred following infusion of a growth factor."
The treatment is, however, still in its infancy and further trials will be needed on a larger number of patients before the therapy can be extended to all patients. "If this treatment proves successful and safe, then it may become more widely available, which would not be for at least a further four to five years," the hospital said.
Mr Nelson, who is still receiving regular courses of the treatment, said he hoped the improvement in his condition would continue. "Walking was also a problem. I used to get very severe dystonia [an involuntary writhing action]. Today, although I still get it, it is much, much less and I can now walk more than a mile before I experience dystonia. It has really improved my mobility dramatically," he said.
Mr Nelson, who is married with two children, said he was diagnosed with Parkinson's several years after he first noticed something was wrong.
"I realised something was not quite right and nobody could quite put their finger on it," he said. "I had a tremor in my right hand and small handwriting – it was my secretary who complained that she could not read my writing any more – but it was some time before I sought some consultation. I was told I had a crick in my neck, a slipped disc in my spine but ultimately it was Parkinson's."
Mr Nelson said he first learnt about the new treatment in February last year at a chance meeting with a consultant looking for volunteers for the trials. He added: "From my personal experience I can only hope that it [the treatment] represents hope for people with Parkinson's but it is early days yet. We are only 12 to 15 months into the trial and it is going to take quite some time for everything to be established.
"But there is no doubt that it has made a very important, positive change to my way of life and hopefully it will be so for others."Reuse content