27 Jun 1997

Researchers in Dr. John Q. Trojanowski's lab at the University of Pennsylvania have discovered a new type of lesion in the brains of Alzheimer's patients. These new lesions appear only in brains with amyloid plaques, including brains of non-demented patients with abundant amyloid plaques, and were rare or absent in the brains of other elderly controls and patients with other neurodegenerative or neuropsychiatric disorders. They are not co-localized with amyloid plaques, and are not visualized by amyloid stains.

They were recognized by four new monoclonal antibodies, and "named" after one of the antibodies, AMY117. These antibodies were orginally generated to paired helical filaments, and unexpectedly labelled the novel AMY Plaques, made up of an as yet unidentified protein(s). It has been speculated, on the basis of the role of proteoglycans in paired helical filaments, that the protein may be proteoglycans or molecules associated with proteoglycans.  It is not known whether these plaques are a precursor to the Alzheimer's senile plaques or whether they are an independent type of lesion, but it is hoped that they may be used as a new marker for Alzheimer's diagnosis.—June Kinoshita