New Gene Therapies May Slow Parkinson's Disease
Two gene therapies for Parkinson's disease are showing promise at preventing the disease's progression and avoiding side-effects of existing
The therapies are being studied by an international team from Lund University in Sweden, the University of Cambridge in the UK and the
University of Florida
One of the treatment approaches is aimed at halting Parkinson's disease at its onset while the other is aimed at avoiding side-effects that
occur when treating the disease in its later stages.
In a study of the first approach, researchers inserted corrective genes into the brain of small monkeys called marmosets.
The genes helped to prevent brain damage by producing therapeutic levels of a protein called glial cell line-derived neurotrophic factor
GDNF helps nourish brain cells and has attracted attention for treating Parkinson's disease.
Its use has been debated, however, since human trials ended last year after trial-conductor Amgen cited safety concerns. Many people with
Parkinson's still want the treatment.
The gene therapy approach appears to produce more manageable levels of the protein in the brain.
In tests with 31 monkeys, GDNF genes inserted into a region in the front part of the brain called the striatum protected monkeys when drugs
were used to induce Parkinson's-like conditions by destroying dopamine-producing cells.
Seventeen weeks after receiving the drug, GDNF-treated monkeys showed improvement in performing tasks and analysis of brain tissue showed the
animals' dopamine systems were spared.
Reversing abnormal movement
In the second approach, researchers used gene therapy to reverse abnormal movements called dyskinesias in some rats.
The approach could combat flailing movements produced by Levodopa, a widely used drug treatment for Parkinson's disease.
While Levodopa usually works well for several years, it can eventually start causing movement problems.
It is hoped that gene therapy could prevent harmful fluctuations of L-dopa, a precursor of dopamine.
In 33 rats with severe dopamine depletion who had limited use of their left paw, gene therapy to provide a source of L-dopa caused complete
recovery of movement.
The studies are reported in the journal Brain and The Journal of Neuroscience.