November 5, 1999/26 Cheshvan 5760, Vol. 52, No.10
Valley doctor aims research at battling Alzheimer'sSystem designed to more quickly test possible cures
CHRIS GARIFO
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 Dr. Eric Reiman points out how positron emission tomography (PET) produces a map of the brain. Photo by Chris Garifo |
Reiman and his colleagues with the Arizona Alzheimer's Research Center - a joint effort of Good Samaritan Regional Medical Center, Mayo Clinic Scottsdale, University of Arizona, Arizona State University, Sun Health Research Institute, Barrow Neurological Institute and Harrington Arthritis Research Center - are working toward one day eliminating Alzheimer's, a progressive, degenerative disease of the brain that leads to dementia. Reiman describes the Alzheimer's "center" as "a statewide laboratory without walls."
November is National Alzheimer's Month. According to the Alzheimer's Association, an estimated 4 million Americans have the disease and, unless a cure or prevention method is found, 14 million Americans will have developed it by the middle of the next century.
The cost to American society each year is at least $100 billion, with the average lifetime cost per patient an estimated $174,000. A patient on average lives eight years, and sometimes as long as 20 years, from the first onset of symptoms.
"We're excited about the chance to help in the effort to find a way to prevent Alzheimer's disease," Reiman says. "That's our goal."
Helping Reiman look inside the brain is a technique called positron emission tomography (PET), an imaging system that allows researchers to see how the brain actually functions. Other imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT), reveal the brain's structure but not how it operates.
"We can use these (PET) techniques to investigate how different parts of the brain work in concert, like members of a symphony, to orchestrate normal behaviors, (including) aspects of emotion, memory, temperature and pain sensation, and hunger and satiation," says Reiman, who is scientific director of the PET Center at Good Samaritan. "And we can investigate how different parts of the brain conspire to produce behavioral disorders."
Reiman explains that PET uses a tracer - radioactive water to measure blood flow and radioactive sugar to measure energy utilization - to see how the brain works.
With PET, Reiman says, researchers can observe changes in the brain that indicate the onset of Alzheimer's years before the patient shows outward symptoms. One benefit of such imaging, Reiman says, is determining the effectiveness and safety of potential Alzheimer's treatments much sooner than previously has been possible.
Among those treatments is a vaccine developed by the Irish pharmaceutical company Elan Inc., announced to the public in July. In experiments with mice, that vaccine reportedly has been demonstrated to reduce and even prevent amyloid plaques - clusters of dead and dying nerve cells, other brain cells and protein that are one of the characteristic structural abnormalities found in the brains of Alzheimer's patients. While such a development is a major landmark, researchers stress that there isn't any evidence yet that what works in mice brains will also be effective for humans. Elan researchers say they want to begin human tests soon.
Also, researchers at Amgen, a California biotech company, reported in late October that they have identified the plaque-causing enzyme called BACE (for beta-site APP-cleaving enzyme). Drug companies now can go to work on a specific medication that targets BACE.
The battle against Alzheimer's is being fought on a variety of fronts, including molecular research that has led to the discovery of a "susceptibility gene" called apolipoprotein E4 (ApoE4), that may serve as an indicator of whether a person is at higher risk of developing the disease.
If and when these latest discoveries lead to actual treatments for Alzheimer's, which currently has no cure, PET technology could help reduce the amount of time it takes for human testing to determine their effectiveness and safety.
Dr. Charles L. Echols Jr., a neurologist with the Barrow Neurological Group in Phoenix, says PET imaging could provide "very helpful information, especially if we have a treatment that could be done early in life, such as in your 20s."
However, he says, "until we have a good way of dealing with the illness, (PET) is just useful information without practical application."
Echols also says the cost of PET imaging could be prohibitive. According to the PET Center, a PET scan costs about $3,300, plus a reading fee which could be another $200.
"Tests (using PET) are very attractive and exciting," Echols says. "But I don't think the cost will ever come down to $15 or $20, like blood tests."
However, he says that, compared to about two years ago, he's "very upbeat" about the advances being made in the fight to stop Alzheimer's.
Reiman, also a professor and associate head of psychiatry at the University of Arizona in Tucson - he teaches students there and in Phoenix - says the Alzheimer's research being done could add to Arizona's prestige within the scientific community. The research center is partially funded by the state and also the Flinn Foundation, of which Reiman recently was elected to the board of directors.
"When you think of exciting developments in Arizona, the work that justifiably gets the most attention is ... exploring the outer reaches of the universe through telescopes and other cosmology research," says Reiman.
"In some regards, we have had until the last two decades, greater access to the outer reaches of the universe than the inner reaches of the mind and brain. Now, using PET and other (imaging) techniques, we have an opportunity to address issues we couldn't address before, learn more about our mind, our brain, ourselves and hopefully develop some clinically useful applications along the way."
Besides its application in the effort against Alzheimer's, PET technology also is proving to be a valuable tool in reducing the risks of, and the need for, costly invasive procedure, Reiman says.
In neurosurgery, for instance, a PET scan can show the surgeon the location of a brain lesion, abnormal blood vessels or a tumor that needs to be removed, in relation to areas of the brain that are critically involved in behavior such as speech, vision and movement. Using PET imaging, the surgeon can tell just how much of the brain area can be safely removed and what might be the safest route through the brain.
PET technology also offers a non-invasive method of determining whether a tumor in the body is malignant or benign and whether cancer has spread.
In cardiology, PET can provide images of blood flow in the heart and help a surgeon decide how effective a heart bypass might be. Reiman explains that PET can reveal whether tissue in a damaged heart is alive or dead. A surgeon then can determine whether a patient is a good candidate for bypass surgery.
"If that heart tissue is alive, bypass surgery will do well in the patient," Reiman explains. "If it's dead, it doesn't matter how much blood flow that part of the heart gets."
PET is also being used in studies of how the brain remembers and how false memories are created within the brain. PET is helping to reveal which parts of the brain are involved with emotions, and it is being used in work with brain abnormalities, such as depression and schizophrenia, though Reiman doubts it will make a good diagnostic tool for such conditions.
The most important work being done with PET, Reiman maintains, is Alzheimer's research. "Our goal is to use imaging techniques like PET to help establish the efficacy of (potential) treatments to prevent (Alzheimer's)," he says. "That's what our whole program is set up to do."
Reiman studied medicine and performed his residency at Duke University. He is a member of Temple Chai in Phoenix and is divorced with two children.