Experts Optimistic About Solving Puzzle of Alzheimer's
WEDNESDAY, June 30 -- Research into Alzheimer's disease has reached a point of significant potential, even as the disease's looming impact on society grows more and more dire, experts say.
Some leading scientists, in fact, worry that we may not be doing enough to press forward with key advances and new insights into Alzheimer's, the most common type of dementia among older people.
An estimated 5.3 million U.S. residents have the disease, which results from the deterioration of nerve cells in the brain and leads to memory loss, impaired judgment, wandering and, as it progresses, to the inability to perform such normal daily functions as dressing, bathing and eating.
As the population ages, the number of people with Alzheimer's is expected to spike dramatically. Today, someone in the United States develops Alzheimer's every 70 seconds, according to the Alzheimer's Association -- a number expected to rise to once every 33 seconds in a few decades.
Scientists researching early detection and treatment for the disease, though, say they are on the verge of substantial advances.
Despite some disappointments, a large slate of Alzheimer's drugs are undergoing human trials, said Dr. John C. Morris, a professor and director of the Alzheimer's Disease Research Center at the Washington University School of Medicine in St. Louis and a spokesman for the American Academy of Neurology.
"There has never been a period in which we had more potential drugs to alter the disease course of Alzheimer's," Morris said. "We have lots of highly promising drug candidates."
The drugs focus mostly on amyloid, a protein that clumps in the brains of people with Alzheimer's.
"Many scientists believe eliminating that accumulation will eliminate Alzheimer's," said William H. Thies, chief medical and science officer for the Alzheimer's Association. "We've seen amyloid accumulation as one of the key markers in the development of Alzheimer's. It's really the first step in taking the basic science of Alzheimer's and using it to develop therapeutics."
However, three of the first anti-amyloid drugs to be tested on people all failed to produce results. Treatment with AN-1792, Flurizan and tramiprosate did not significantly improve the symptoms of people with Alzheimer's.
Part of the problem could have been that the drugs were tested on people with advanced Alzheimer's, Morris said, adding that they might be more effective if given to people in earlier stages of the disease.
But that requires a means to detect Alzheimer's disease early in its development or even to flag people who are at risk for developing the disease. The only way doctors have been able to diagnose Alzheimer's is when symptoms appear, and by then the damage has already been done, Morris and Thies said.
That might be about to change. Work is being done on scans and tests that could lead to the early detection of Alzheimer's.
Researchers are identifying substances that bind with amyloid deposits and make them visible to imaging scans, such as the PET, or positron emission tomography, scan. Previously, amyloid clumps have been invisible to scanning technology, and the only way doctors have been able to detect their presence in a human brain was during an autopsy, Morris said.
Researchers also are identifying genetic and biological markers that could indicate that a person is at increased risk for developing Alzheimer's.
"The excitement in the field is, yes, new imaging technology, and studies of amyloid beta in the spinal fluid of elderly and middle-age people do seem to identify people who, if they continue to live, will develop dementia," Morris said. "This will set the stage for targeting people at high risk of developing dementia if they live long enough."
Thies sees these two areas of research -- detection and treatment -- spurring each other along as progress is made.
"There's no doubt in my mind that, as an effective therapy emerges that slows down the course of the disease, we will find the marker for it," Thies said. "The two are linked almost arm-in-arm and will develop together. Advances in one will drag the other along."
Some people, however, question the direction of research -- worrying that efforts have been too tightly focused on eliminating amyloid from the brain, particularly given the failures in early trials.
"People who work in the field raise the question, 'Should we be doing all this amyloid work?'" Thies said. "But it's the most mature of the ideas so you have to follow it through."
Questions also have arisen as to whether Alzheimer's research is getting enough attention. Money spent by the government on Alzheimer's, for instance, lags behind research funding for other major diseases. The U.S. National Institutes of Health expects to spend $527 million on Alzheimer's disease research in the current fiscal year, compared with $6.1 billion on cancer research, $3 billion on HIV/AIDS and $1.9 billion on heart disease research, according to spending data released Feb. 1.
This disparity in spending on Alzheimer's stems in part from the fact that the United States does not have a national plan aimed at tackling research and treatment, Harry Johns, chief executive of the Alzheimer's Association, told HealthDay. England, France and Australia have such plans, but the United States does not, he said.
That might be in part because many Americans see Alzheimer's as an inevitable end-of-life disease. "A lot of people still equate getting older with loss of cognitive process," Morris said. "They consider it a part of getting older. They don't see it as a disease that reduces life span."
Whatever the reason, researchers say that the aging of the U.S. population means that Alzheimer's needs to be tackled now or the United States will face a public health crisis later.
"Alzheimer's is not only an awful disease, it's also very expensive," Thies said, noting that a person aging with Alzheimer's disease will require care that costs up to three times as much as care for a person aging normally.
"With the aging of our population, we are going to have an immense increase in Alzheimer's disease over the next 40 years," he said. "If we don't deal with this, it could bankrupt our government and wreck our health-care system."
Posted: June 2010