Eye cell transplants aid Parkinson's patients

11.00am

WASHINGTON - Eye cells transplanted into the brains of Parkinson's patients have markedly improved their symptoms and may provide an alternative to steadily increasing doses of medication, doctors say.

The eye cells produce dopamine, the important chemical lacking in the brains of people with Parkinson's, whose disease begins with trembling or stiffness and progresses to a rigidity that leaves them virtually paralysed.

Dr Ray Watts, a professor of neurology at Emory University School of Medicine in Atlanta, today said six patients who got the eye cell transplants showed a regression of their symptoms.

"We've been following these six participants for over a year, and we've found they've improved, on average, nearly 50 per cent in motor function," Watts, who presented his findings to a meeting in Denver of the American Academy of Neurology, said in a statement.

The cells used are found in the retina, the lining of the back of the eye.

"They make dopamine and you can grow them well in culture," Watts said in a telephone interview. "You can produce hundreds of millions of cells from a single donor."

Watts said no one knows why the cells produce dopamine, a neurotransmitter or message-carrying chemical that, in the brain, is associated with movement.

It is the loss of dopamine-producing neurons in the brain that causes Parkinson's.

Many researchers are trying different kinds of transplants to treat Parkinson's, which affects more than a million people in the United States alone. These include cells from pig fetuses, from human fetuses and stem cells, the body's master cells that can sometimes be induced to form brain tissue.

Watts' team used retinal cells taken from the bodies of people who donated their eyes after death. There is little risk of an immune system rejection because the brain does not have the same level of immune activity as the rest of the body.

The cells were prepared with a gelatin product called Spheramine, developed by South San Francisco-based Titan Pharmaceuticals, Inc.

"These cells are making L-dopa and or dopamine and serve, in the brain, as a more continual production site than just taking medications by mouth every two hours," Watts said.

L-dopa is one of the standard treatments for Parkinson's and Watts said the improvement he saw in the patients was comparable to when they take the drug.

Standard tests used to measure a patient's tremors, ability to move and other symptoms showed they got better after the implants, Watts said.

"At 12 months they averaged a 48 per cent improvement, which is substantial," he said. One patient had a 60 per cent improvement. One patient had had the implants for nearly two years and maintains the benefits.

"Not everybody has the same symptoms, but if they had slowness and stiffness and trouble walking generally, those were the symptoms that got better," Watts said.

The problem with drugs given to Parkinson's patients is that the effects wear off more and more quickly as the disease progresses. Patients have to take bigger doses.

"Then they start to get complications," Watts said. Sometimes these complications are as bad as the initial Parkinson's symptoms.

"We need more sustained delivery mechanisms," Watts said. "These cells are one approach to that for patients with advanced Parkinson's who are not optimally controlled with their medications."

- REUTERS

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