July 17 (Bloomberg) -- Medical researchers say they are beginning to observe Alzheimer's disease as it progresses by producing some of the first pictures of the physical changes that take place in the brains of living adults.
Two studies using PET scans helped doctors spot problems in the brains of people with Alzheimer's before symptoms, such as memory loss, became obvious, scientists said. Research using an MRI in another study showed that only patients with a certain genetic variation benefited from taking the drug Aricept, made by New York-based Pfizer Inc. and Japan's Eisai Co.
These studies are among the first to report definitive results from the use of medical imaging tests that track the illness as it advances. Being able to detect the brain's reaction to treatment may help speed discovery of new medicine, researchers said at an international meeting today.
``We are beginning to measure changes in the biology of the disease, instead of asking people questions to try to ascertain the quality of their memory,'' says William Thies, vice president for medical and scientific relations of the Chicago- based Alzheimer's Association.
A century after the memory-robbing disease was first identified, researchers described advances that may finally thaw the glacial pace of innovation. The ailment, which afflicts 28 million people worldwide, still can only be diagnosed with certainty after a person dies, when pathologists can physically examine the brain in an autopsy.
International Conference
The new imaging studies were presented at the 10th International Conference on Alzheimer's Disease and Related Diseases in Madrid.
About 4.5 million Americans have Alzheimer's disease, which robs the brain of its memory and processing skills. The number of victims is expected to grow fourfold by the middle of the century as the population ages and baby boomers reach retirement, according to the Alzheimer's Association.
``This is the time to move forward and not wait for the inundation of baby boomers to overwhelm our health-care system,'' says John Morris, professor of neurology and director of the Alzheimer Disease Research Center at Washington University School of Medicine in St. Louis.
The studies, using approaches licensed to General Electric Co. and Siemens AG, injected chemicals into the bloodstream that migrated to brain, where they bound to abnormal proteins. The chemicals were then traced using PET scans, helping researchers create a precise picture of just how diffuse the damage can be.
`Able to Differentiate'
``The technology appears to be able to differentiate Alzheimer's disease from normal aging,'' said Gary Small, the lead researcher on one study and director of the University of California, Los Angeles's Center on Aging. ``As people get more impaired, the binding in the brain increases. This gives us a full picture of Alzheimer's disease progression.''
His research, involving 60 volunteers, evenly split into groups of healthy people and those with mild impairment or Alzheimer's disease. In the other study involving PET scan use, researchers at the University of Pittsburgh examined 47 patients with Alzheimer's, mild disease or no memory problems.
Results from the studies aren't definitive enough for doctors to start using brain imaging immediately to diagnose Alzheimer's, or predict which people with mild impairment will grow worse with time, the researchers said. More work is needed to confirm and expand on the findings and determine which methods are most accurate, they said.
Aricept
The study involving use of an MRI, done by researchers at the Mayo Clinic in Rochester, Minnesota, pinpointed which patients benefited from taking the drug Aricept, made by New York-based Pfizer Inc. and Japan's Eisai Co.
This study found that the amount of brain shrinkage seen in an area of the brain called the hippocampus was reduced using Aricept only in people with mild impairment and a genetic variation that put them at risk for an early and aggressive form of Alzheimer's disease, researchers said.
About 15 percent of people have the so-called ApoE genetic variation that increases their risk for Alzheimer's. ApoE helps make a protein that carries cholesterol in the blood.
``Prevention of the conversion from mild cognitive impairment to Alzheimer's disease is an important therapeutic goal,'' said Clifford R. Jack, a professor of diagnostic radiology, in a press conference. ``This is the first study that shows a treatment effect on brain shrinkage.''
New Treatments
Better insight into the brain is key for the development of new treatments for Alzheimer's disease, the researchers said. The condition is so complex, and the brain is so difficult to manipulate, that doctors still have few options. Existing drugs ease symptoms without slowing Alzheimer's inexorable advance.
These medicines include Aricept, Razadyne from New Brunswick, New Jersey-based Johnson & Johnson, and Exelon, sold by Novartis AG of Basel, Switzerland.
Researchers hope imaging studies will eventually offer two advantages -- measuring brain health in much the same way cholesterol and blood pressure tests scope heart disease, and helping determine if new drugs are having a biological effect.
Forty-two drugs are now in development for Alzheimer's, said the Pharmaceutical Research and Manufacturers of America.
``The hope is by developing these kinds of biological markers, we'll be able to make these clinical trials more efficient and effective, and we'll be able to look at more drugs,'' says Neil Buckholtz, an official with the U.S. National Institute on Aging.
Studies at the Madrid meeting, attended by about 5,000 researchers, also explore ties to diabetes and heart disease.
Researchers from the Karolinska Institute in Stockholm, for instance, presented a study yesterday showing people with higher than normal sugar levels have a 70 percent greater risk of developing Alzheimer's than those with normal sugar levels.
That condition, called pre-diabetes, affects 41 million Americans ages 40 to 74, according to the American Diabetes Association Web site.
To contact the reporter on this story:
Michelle Fay Cortez in Minneapolis at
mcortez@bloomberg.net
Last Updated: July 17, 2006 12:41 EDT
