Small Step Made Toward Parkinson's Vaccine
Progress Reported in Tests on Mice; Much Work Ahead Before Use in Humans
June 15, 2005 -- Researchers have made progress in the effort to create a vaccine against Parkinson's disease.
The strides were seen in tests on mice. It's not known if years of additional research will eventually help prevent or cure the disease in people. Still, "this shows the first demonstration of a vaccine for this family of disease," says Eliezer Masliah, MD, in a news release.
Masliah is a neurosciences and pathology professor at the University of California at San Diego (UCSD). He and colleagues from UCSD and Elan Pharmaceuticals worked on the vaccine project, which is described in Neuron's June 16 issue.
In Parkinson's disease, brain cells that make a chemical called dopamine break down. The brain needs dopamine to help coordinate the body's muscle movements. As dopamine levels fall, so does the ability to produce smooth, purposeful muscle movement.
That can prompt shaking, often in a hand or arm. Other Parkinson's symptoms include stiff, achy muscles; slow movement; difficulty walking; balance problems; and weak facial and throat muscles.
There is no cure for Parkinson's disease, but treatment can help manage symptoms. The disease is mainly seen after age 50, though some people are diagnosed at a younger age. It is not a contagious disease, nor is it inherited. It's not a normal part of aging, but the symptoms of Parkinson's disease worsen with time.
Family of Diseases Targeted
Another hallmark of Parkinson's disease is a brain buildup of clumps of protein called abnormal alpha-synuclein. Those clumps, known as Lewy bodies, are also sometimes seen in people with dementia.
Lewy bodies don't appear to be innocent bystanders in the brain. They're associated with nerve- cell breakdown, hampering communication between nerve cells. That can set the stage for Parkinson's disease and dementia.
The experimental vaccine takes aim at Lewy body diseases, including Parkinson's. The mice were injected or immunized for eight months with human alpha-synuclein. This caused them to develop antibodies, a type of protein that binds to and destroys alpha-synuclein.
The most effective antibodies helped mice block the protein's troublesome buildup.
A vaccine for humans might be a bit different from the one used on the mice.
"We would not want to actively immunize humans in this way by triggering antibody development, because one could create harmful inflammation," says Masliah. "However, it might be feasible to inject antibodies directly, as if the patient were creating his or her own," he says.
The research team is now looking for alternative ways to make those antibodies. That could take many years and may not bear fruit, says the news release.