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Researchers hail possible breakthrough in Alzheimer's disease
Discovery could lead to early diagnosis, treatment
June 26, 1997
Web posted at: 10:48 p.m. EDT (0248 GMT)PHILADELPHIA (CNN) -- Scientists believe they have discovered lesions composed of a previously unidentified protein that could lead to early diagnosis and treatment of Alzheimer's disease.
"This is a spectacular lesion, never before seen, that tracks closely with the disease state," said Dr. John Q. Trojanowski, director of the Alzheimer's Disease Center at the University of Pennsylvania.
Trojanowski is the senior author of a study reporting the findings in the July issue of the American Journal of Pathology.
Alzheimer's is a mind-robbing brain disease that generally strikes people over 65, and for which there is no known cure.
It is named after German neurologist Alois Alzheimer who, in 1907, identified the two primary characteristics of the disease -- tangling of the nerve fibers and plaque coating the nerve cells.
The plaque Alzheimer identified is formed by amyloid, or waxy proteins, but Trojanowski's team found new lesions made of different material.
New lesions show up only in Alzheimer's sufferers
"It occupies as much of the Alzheimer's brain as amyloid plaques do," Trojanowski says. "As a result, we have every reason to suspect that this pathology will be found to play a crucial role in the development and progression of Alzheimer's disease."
During a two-year study, Trojanowski's team examined tissue from 81 brains -- 40 from Alzheimer's patients and 41 from people who were normal or were victims of other forms of dementia.
Some of the latter group showed signs of amyloid plaque, but the patients had not been diagnosed with Alzheimer's. The new lesions showed up only in brains containing the amyloid plaques.
"Our view is if plaques and tangles were to be eliminated from the Alzheimer brain, and patients were not to get better," Trojanowski says, "maybe it's because they have deposits of this other plaque. We may, in fact, have to have therapies targeted at each of these abnormalities."
"This is quite illuminating and potentially very significant," said Zaven Khachaturian, director of the Alzheimer's Association's Ronald & Nancy Reagan Research Institute. "If confirmed, this finding may provide new insights to our understanding of the disease."
Protein may be new 'marker'
Khachaturian said the new protein may provide a new "marker" for diagnosis or a target for treatment.
"It gives scientists and the medical profession new ways of understanding what might be causing the disease." he said. "What's more important, it would also give us potential for developing new diagnostic tools as well as developing new therapies."
The researchers said the new protein was found when they used a different method of detecting the plaques and tangles in brains with the disease.
"The staining and chemical dye methods that have been used in the past to label Alzheimer's disease pathologies -- primarily silver and thioflavin staining -- do not pick up this lesion," said Virginia M.Y. Lee, a professor of pathology and laboratory medicine who collaborated on the research.
The new plaque and its protein have not been named yet, although Trojanowski refers to it as an "AMY-plaque" because an antibody called AMY117 was used in the laboratory to get a look at the new lesion.
Protein could be a target of therapy
"Perhaps one could develop an assay useful for diagnosis early in the disease state," Trojanowski says. "One of the important goals of Alzheimer's research now is figuring out how to identify the disease years before you encounter problems."
He added: "If we learn more, we could make this protein a target of therapy -- find a drug to block its formation."
Correspondent Rhonda Rowland and The Associated Press contributed to this report.
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