Gene therapy treatment offers Parkinson's relief
WASHINGTON (Reuters) - Two studies published on Thursday offer new hope for Parkinson's disease -- one using gene therapy to treat the symptoms and another investigating a drug that might stop the incurable disease in its tracks.
While both are in early experimental stages, each takes a new approach to treating the devastating brain condition, which affects millions of people globally.
In the gene therapy trial, Dr. Michael Kaplitt of New York-Presbyterian Hospital/Weill Cornell Medical Center and colleagues used a harmless virus called an adeno-associated virus to carry a new gene into the brains of 11 volunteers with advanced Parkinson's disease.
They found it had no ill effects and appeared to reduce their symptoms, and the benefits lasted for four years in some.
"These exciting results need to be validated in a larger trial, but we believe this is a milestone -- not only for the treatment of Parkinson's disease, but for the use of gene-based therapies against neurological conditions generally," Kaplitt said in a statement.
The idea behind gene therapy is to replace faulty genes or augment the activity of beneficial genes. In the past the approach has had mixed success. In one trial in 1999 one patient died, while in another two people developed leukemia as a result of such treatment.
In the latest attempt, the gene that was delivered to the Parkinson's patients controls production of an enzyme called GAD or glutamic acid decarboxylase. GAD controls a neurotransmitter or message-carrying chemical called GABA.
GABA calms overactive neurons, and its production is lost in Parkinson's. This helps cause some of the jittery and shaky movements that mark the disease.
Writing in the Lancet medical journal, the researchers said their volunteers had about a 27 percent improvement in symptoms.
"Because this was the first such study of its kind, we targeted just one side of the brain initially out of concerns for the patients' safety," Dr. Matthew During of Ohio State University, who worked on the study, said in a statement.
Brain scans showed a change in brain cell activity on the treated side of the brain, he said.
The researchers have formed a company called Neurologix, based in New Jersey, to develop the treatment.
In another study, published in the journal Science, a team at Massachusetts General Hospital and Harvard Medical School said they had designed a drug that can protect the neurons damaged in Parkinson's disease.
The drug blocks the action of an enzyme called SIRT2, a member of a group of enzymes called sirtuins, which are involved in the aging process.
"By inhibiting SIRT2 we protect neurons from cell death," Aleksey Kazantsev, who led the study, said in a telephone interview.
They have tested their drug in lab dishes and in fruit flies, which can be engineered to develop a condition highly similar to Parkinson's in humans.
The researchers are also testing their approach in other brain diseases, including Huntington's and Alzheimer's.
Current drug treatments for Parkinson's all eventually stop working. Electronic stimulation is still experimental, although it may help, and researchers are also testing ways to transplant new brain cells into patients.
