Gene therapy has removed the symptoms and stopped the progression of Parkinson鈥檚 disease in monkeys.
The effects should be long-term, say the researchers in the US, who believe their study raises hopes for an effective treatment for human sufferers.
The scientists injected the monkeys鈥� brains with a lentivirus modified to carry the gene for glial-derived neurotrophic factor.
Advertisement
GDNF protects dopamine-producing cells in a region of the brain called the substantia nigra, and boosts levels of dopamine. A decline in dopamine levels caused by the death of substantia nigra cells is responsible for the tremors and difficulty in moving associated with Parkinson鈥檚.
鈥淥ur study suggests a new approach to forestall disease progression by delivering potent factors with effects that are both long-term and non-toxic,鈥� says Jeffrey Kordower of the Rush-Presbyterian-St Luke鈥檚 Medical Center in Chicago.
Kordower鈥檚 team injected the lenti-GDNF into the brains of eight 25-year-old rhesus monkeys showing early signs of Parkinson鈥檚 disease. After three months there was a dramatic increase in the production of dopamine in the monkeys鈥� brains, with levels similar to those found in young monkeys. The disease symptoms had disappeared.
The team also gave 20 young monkeys a chemical that induces a Parkinson鈥檚-like state. One week later, they injected the monkeys鈥� brains with lenti-GDNF. The symptoms vanished and there was no degeneration of the dopamine-producing cells.
A third group of healthy monkeys received lenti-GDNF and were allowed to live longer after treatment. High levels of GDNF were found in the animals after eight months, suggesting that the injections could have a long-term effect on Parkinson鈥檚 patients.
Kordower hopes human trials of lenti-GDNF injections could take place within five years.
Earlier this month, a team at the University of Tubingen in Germany used a virus to deliver the gene for GDNF to the brains of mice with a syndrome similar to Parkinson鈥檚 (快猫短视频, 21 October 2000, p 12). They also reported good results, but the effects lasted for only around a month. The German team thinks clinical trials could begin in two years.
Source: Science (vol 290, p 767)