For a perfectly healthy woman, Dianne Kerley has had quite a few medical tests in recent years: MRI and PET scans of her brain, two spinal taps and hours of memory and thinking tests.
Kerley, 52, has spent much of her life in the shadow of an illness that gradually destroys memory, personality and the ability to think, speak, and live independently. Her mother, grandmother and a maternal great-aunt all developed Alzheimer's disease. Her mother, 78, is in a nursing home in the advanced stages of dementia, helpless and barely responsive.
Kerley is part of an ambitious new scientific effort to find ways to detect Alzheimer's disease at the earliest possible moment. Although the disease may seem like a calamity that strikes suddenly in old age, scientists now think it begins long before the mind fails.
"Alzheimer's may be a chronic condition in which changes begin in midlife or even earlier," said Dr John C Morris, director of the Alzheimer's Disease Research Centre at Washington University in St Louis, Missouri, where Kerley volunteers for studies.
Currently, the diagnosis is not made until symptoms develop, and by then it may already be too late to rescue the brain. Drugs now in use temporarily ease symptoms for some, but cannot halt the underlying disease.
Many scientists believe the best hope of progress lies in detecting the disease early and devising treatments to stop it before brain damage becomes extensive. Better still, they would like to intervene even sooner, by identifying risk factors and treating people preventively.
So far, Alzheimer's has been unyielding. But research now under way may start answering major questions about when the disease begins and how best to fight it.
A radioactive dye called PIB has made it possible to use PET scans to find deposits of amyloid, an Alzheimer's-related protein, in the brains of live human beings. It may lead to earlier diagnosis.
Currently, for the most common form of Alzheimer's disease, which occurs after age 65, there is no proven means of early detection, no definitive genetic test. But PIB tests might be ready before new treatments emerge, making it possible to predict who will develop Alzheimer's.
Researchers are also using MRI scans to look for early brain changes, and testing blood and spinal fluid for amyloid and other "biomarkers" to see if they can be used to predict Alzheimer's or find it early.
Studies of families in which multiple members have dementia are helping to sort out the genetic underpinnings of the disease.
Finally, experiments are under way to find out whether drugs and vaccines can remove amyloid from the brain or prevent its buildup. The new drugs have the potential to stop or slow the progress of the disease.
The potential market for prevention and treatment is enormous, and drug companies are eager to exploit it.
Researchers are especially eager to study people like Kerley, because the children of Alzheimer's patients have a higher-than-average risk of dementia themselves, and tracking their brains and minds may open a window onto the earliest stages of the disease.
In her heart, Kerley suspects that her mother's Alzheimer's disease began long before the official diagnosis in 2001 or even the tentative one in 1995 - years before, maybe decades.
When does Alzheimer's begin? The question haunts families and captivates scientists.
Several studies in which people had intelligence tests early in life and were then evaluated decades later have found that compared with the healthy people, those with Alzheimer's had lower scores on the early tests.
The widely dispensed advice is to read, take courses, solve puzzles and stay mentally active to ward off Alzheimer's. But does that mean that mental activity prevents Alzheimer's - or vice versa?
The leading theory of Alzheimer's says that beta amyloid, or A-beta, is the main culprit, building gradually in the brain over decades and short-circuiting synapses, the junctions where nerve cells transmit signals to one other. Gradually, the theory goes, the cells quit working and die.
Several drugs and vaccines are now being tested that either block the production of A-beta or help the body get rid of it.
Some researchers are less enthusiastic, noting that there have been numerous failures along the way. Even if current research yields new drugs, there is not likely to be a miracle pill that will bring people back from deep dementia. For now, there is no choice but to cope with the disease.
New York Times
Eat fish, fight Alzheimer’s
Studies on rodents and people suggest that a diet rich in DHA, an omega-3 fatty acid found in fish oil, helps delay or prevent Alzheimer's disease. Now University of California, Los Angeles researchers have come up with a possible explanation.
A team led by Greg Cole, professor of neurology at UCLA's David Geffen School of Medicine, has concluded that the DHA protection has to do with a key brain protein called LR11, which helps destroy the toxic plaques that lead to Alzheimer's. Scientists know the brains of deceased Alzheimer's patients contain lower-than-normal levels of LR11 and have wondered if increasing the LR11 levels could help delay or prevent the disease.
So Cole's team added DHA to the diets of rodents who had been altered genetically to develop an Alzheimer's-like disease. The DHA, indeed, increased brain levels of LR11. The scientists also exposed human brain cells to DHA in petri dishes and found it increased the amount of the protective protein inside the cells.
Increasing consumption of DHA, which has been shown to decrease the risk of cardiovascular disease, also might reduce risk for Alzheimer's, Cole says. Added omega-3s are found in some eggs and dairy products. And, of course, people can eat more fish or talk to a physician about adding a fish oil supplement or one with DHA derived from algae to their diets.
Susan Brink
Los Angeles Times
