Analysis: Parkinson's Great Genetic Hope?

Jun 21, 09:28 PM

Current Headlines: By ADRIANNE APPEL

In the first study of its kind, genes injected into the brains of 12 Parkinson's patients significantly improved symptoms for up to one year, scientists said Thursday.

The early study paves the way for similar and larger studies over the next few years, the researchers said.

Patients can take hope. I can't promise this will be the ultimate therapy for them, but our hope is that, at least our initial success in that this technique is safe and shows encouraging effectiveness, will provide an important milestone, lead scientist Michael Kaplitt, a professor and director of movement disorders surgery at NewYork-Presbyterian Hospital/Weill Cornell Medical Center in New York, told United Press International.

Symptoms among the 11 men and one woman were reduced by an average of 25 percent, said Kaplitt, whose results will be published in the June 23 Lancet.

Parkinson's is a degenerative neurological illness with symptoms including tremors, stiffness and the inability to initiate movement. The symptoms are caused by low levels of the brain chemicals dopamine and GABA, which are neurotransmitters.

Over time in Parkinson's patients, brain cells that make dopamine perish.

About 1.5 million people in the United States have Parkinson's, with the disease afflicting mostly people over the age of 65.

The patients in the study had advanced Parkinson's symptoms and had lived with the disease an average of eight to 10 years, Kaplitt said.

Nathan Klein of Port Washington, N.Y., was one of the 12 in the study. He received the genes in 2003, to help with tremors in one arm and a shuffling gait.

He's doing very well. He's not totally asymptomatic, but he doesn't have tremors that he had before, Kaplitt said.

The novel gene technique was first tried in animals a few years ago to much fanfare, but the present study was the first of its type in humans.

It's a great idea, a promising idea, Burton Scott, assistant clinic professor of medicine at Duke University, told UPI.

But a blind study, in which some patients are treated and some are not, is the next step for any similar study so that any placebo effect can be noted, he said.

The primary purpose of this study was to determine if the therapy is safe and effective, Kaplitt said.

In the technique, a surgeon makes a quarter-sized hole in the brain, inserts a tube the width of a human hair and injects a drop of fluid holding 3.5 billion to 35 billion genes that are contained within a harmless virus, known as a viral vector. The genes are called glutamic acid decarboylase. The GAD genes produce GABA, a neurotransmitter that helps quiet overactive neuronal firing in the brain.

The hyperactive firing happens in Parkinson's patients and makes it difficult to coordinate movement.

It's a technique that has had people sitting on the edges of their chairs based on previous animal work, Ariel Deutch, a professor at Vanderbilt University School of Medicine in Nashville and chair of the Scientific Advisory Board for the National Parkinson Foundation, told UPI.

New ways to treat the disease are needed, Deutch said. The disease is currently treated with drugs or surgery. While the drugs are often effective for many years, they also cause side effects and in many people lose their effectiveness over time.

The brain region that the researchers operated on is called the sub-thalamic nucleus, and it is well known to Parkinson's surgeons like Kaplitt.

It's the same area we use in traditional surgery, in which batteries and wires are implanted in the brain, he said.

We thought, why not replace wires and batteries with a more genetic, natural approach to allow the brain to make what it needs? Kaplitt said.

The study was restricted by federal overseers to giving the injections on just one side of the brain, even though both sides are impaired in Parkinson's. This was done for protection of the patients because if something went wrong, a patient would theoretically still have one half of his brain untouched.

The one side treated, one side not rule meant that the scientists could compare how the treated half of the brain functioned compared to the untreated half.

We were able to compare the treated with untreated side in the same patient, Kaplitt said. It did obviously limit the degree of improvement because we were only treating one side, he said.

Any future studies will hopefully be cleared to treat both sides of the brain, Kaplitt said.