DOUBLE gene therapy can stop Parkinson’s disease progressing—at least
in mice. The cocktail keeps affected brain cells healthy.
In people with Parkinson’s, the brain cells that produce a neurotransmitter
called dopamine die off. This leads to stiff muscles, tremors and slow or frozen
movement. The main treatment is drugs that boost levels of dopamine. If this
fails, the last resort is surgery—removing parts of the brain can relieve
symptoms. “These are drastic procedures,” says David Latchman of Britain’s
Parkinson’s Disease Society.
Now neurologist Jörg Schulz and his colleagues at the University of
TĂĽbingen in Germany have shown that gene therapy might be able keep the
dopamine-producing cells alive. It isn’t known why these neurons die, but it
seems something is forcing them to commit suicide. A key factor in cell suicide
is an “executioner” molecule called caspase.
Advertisement
So the researchers put the gene for a protein that blocks caspase into a
virus and injected it directly into the brains of mice with a syndrome similar
to Parkinson’s. This prevented neurons dying, but they still failed to make
dopamine. Next, the researchers added a gene for a growth factor called GDNF to
the virus. This time, the cells carried on making dopamine. “This not only
ameliorates the symptoms, it stops the progression of the disease as well,” says
Schulz.
So far, the effects only last a month or so. The researchers hope to improve
the treatment enough for clinical trials to begin in about two years, they told
a meeting of the American Neurological Association in Boston last week. “It is a
very promising approach,” says Latchman. But he warns that while many treatments
work in animals, the difficulty is in getting them to work in humans.
