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USF is among 15 U.S. medical centers involved in a clinical trial of draining toxic proteins with plastic shunts.
By WES ALLISON
© St. Petersburg Times, published September 16, 2001
With few effective drugs available, researchers will try draining toxins from the brains of Alzheimer's patients in hopes of slowing the disease and its mind-wasting effects.
Fifteen U.S. medical centers, including the University of South Florida in Tampa, are participating in a clinical trial in which shunts will be implanted in the skulls of Alzheimer's sufferers. These plastic shunts then will drain two types of toxic proteins, called beta amyloid and tau, that accumulate in the brains of people with Alzheimer's.
A total of 250 patients, ages 62-85, are being sought. USF hopes to enroll 20-30 of them.
"In some sense, it gives you a measure of how difficult it is to treat this thing, that surgery would be tried," said Dr. Michael Mullan, a neuroscientist and director of the USF Roskamp Institute for Alzheimer's Research.
"But on the other hand, I think the basis of this is fairly sound, and probably at this stage it has as good a chance of being effective as the currently available drugs."
USF is the only participating medical center in Florida. Mullan and his colleagues at Roskamp were among the first scientists to identify beta amyloid and tau as key reasons behind the devastation of Alzheimer's, a degenerative brain disease that affects about 4-million Americans.
The proteins apparently interfere with cognitive function by causing inflammation of brain cells and short-circuiting communication between neurons. It's unclear if the accumulations of these proteins cause the disease or are simply byproducts of it.
In healthy people, fresh cerebrospinal fluid bathes the brain and spinal column every day. As we age, the production of this fluid decreases, and the brains of people with Alzheimer's are flushed about one-fourth as quickly as the brains of healthy people.
Scientists have documented a correlation between the amount of beta amyloid and tau proteins in the brain and the severity of impairment from Alzheimer's.
"The premise is that these proteins go from being soluble to becoming insoluble, and therefore deposit in the brain," Dr. Thomas Freeman, a neurosurgeon at USF and Tampa General Hospital and the study's lead investigator, said last week.
"If the process of deposits in the brain is causing the changes seen in Alzheimer's disease, and you can get rid of these deposits, that should help change the progression of the disease."
The shunt is a modified version of a device used to drain fluid from the brains of injured or sick adults and children. It was developed by researchers at Stanford University who formed a company, Eunoe Inc., to test and market it. Eunoe is paying for the trial.
In a pilot study of 29 patients conducted by Eunoe, 90 percent showed stable or improved mental function six months after having the shunt implanted. The level of amyloid and tau proteins in their brains also decreased.
The national study will last 18 months. All patients will be surgically fitted with a shunt just below the ear. A drainage tube will run beneath the skin to the abdominal cavity, where the fluid will be re-absorbed and processed by the body.
The shunts in half the patients won't be activated for nine months, to provide a comparison of patients with the shunt and patients without it. After nine months, their shunts will be activated and will begin draining fluid.
All patients will be tested periodically to measure their mental function. Researchers also will test their cerebrospinal fluid for levels of proteins.
"In about two years, we'll have the final data as to whether this is a true treatment or not," Freeman said.
Anyone interested in participating in the trial should call (813) 974-3100.