Researchers experimenting with monkeys successfully tested a gene therapy technique that reversed the brain damage associated with Parkinson’s disease.
For reasons that are still not understood, people suffering from Parkinson’s disease do not produce enough of the brain chemical dopamine which is necessary for signals in the brain to be transmitted. As a result Parkinson’s sufferers experience a degenerative loss of motor control including difficulty walking, talking, smiling and swallowing. Secondary effects such as pneumonia and stroke end up killing many with Parkinson’s diseases.
In a study published in Science, scientists used a group of eight monkeys with a Parkinson’s-like disease and another group of eight monkeys without the disease. The monkeys suffering from the brain disease were injected with a genetically altered virus that was designed to boost dopamine production within the brain.
In both cases the virus dramatically boosted brain dopamine levels over the eight months of the of the study and ameliorated the Parkinson’s-like symptoms that the monkey’s experienced. Three of the monkeys in the first group who had severe Parkinson’s symptoms were restored to almost normal motor functions according to study author Jeffrey Kordower.
In the second group, five of the monkeys who developed Parkinson’s were given the virus while five were not. One monkey in each group died for unknown reasons. Of the four in each group left, three with the Parkinson’s symptoms were completely free of the disease after receiving the virus injection, while all four monkeys in the control group became severely impaired.
The researchers will soon be present the FDA with a proposal to test the gene therapy in humans and such trials could begin in 3 to 5 years. One possible obstacle is that the researchers are not sure if the brain cells that are responsible for dopamine production in human beings will respond in the same way that their counterparts in the monkeys did. Even if they don’t, however, this is important evidence that gene therapy designed to modify brain cells of Parkinson’s suffers to boost dopamine levels is likely to be a very viable avenue of research, even if the methods used to get there might be different in human beings than in monkeys.
Hope of Parkinson’s ‘cure’. The BBC, October 27, 2000.
Gene therapy may relieve Parkinson’s disease. Paul Recer, The Associated Press, October 26, 2000.