beta-Amyloid protein is higher in Alzheimer's disease brains: description of a quantitative biochemical assay.
Deposition of beta-amyloid protein (A beta) in senile plaques and in the walls of cerebral vessels is a pathologic hallmark of Alzheimer's disease (AD). The current diagnostic criteria for AD requires the presence of neurofibrillary tangles and a minimum number of senile plaques in cortex. Senile plaques are readily visualized by silver staining or immunocytochemistry using antibodies raised to A beta. Available histochemical and immunocytochemical methods are sensitive but the results may occasionally be variable and sampling from many brain regions is difficult and impractical. This study describes a simple biochemical method for quantifying the A beta load in unfixed brain homogenates. The immunoassay recognizes all forms of A beta deposits (neuritic and diffuse plaques, and cerebrovascular amyloid) and has a sensitivity and specificity comparable to immunocytochemistry. In direct comparisons, results from the dot blot method correspond well with both Western blot analysis of partially purified A beta and plaque counting by immunocytochemistry. In a retrospective series of 39 postmortem AD and control cases, the amount of A beta in brain by dot blot immunoreactivity effectively separated the two groups. Therefore, this method provides a rapid, sensitive, and accurate quantitation of A beta in postmortem brain tissue and represents an alternative approach for studying A beta deposition in aging and AD.
Frucht
S J
SJ
Department of Pathology, Harvard Medical School, Boston, MA.
Koo
E H
EH
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000032:analysis*; D015153:Blotting, Western; D001921:Brain / Q000473:pathology; D001923:Brain Chemistry; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008875:Middle Aged; D016874:Neurofibrillary Tangles / Q000473:pathology; D016622:Silver Staining
D016229:Amyloid beta-Peptides