Levels of alpha- and beta-secretase cleaved amyloid precursor protein in the cerebrospinal fluid of Alzheimer's disease patients

Alternative cleavage of the amyloid precursor protein (APP) results in gene ration and secretion of both soluble APP (sAPP) and beta-amyloid (A beta). A beta is the main component of the amyloid depositions in the brains of Al zheimer's disease (AD) patients. Using Western blotting, we compared the le vels of alpha-secretase cleaved sAPP, beta-secretase cleaved sAPP and total sAPP, in cerebrospinal fluid (CSF) from 13 sporadic AD patients and 13 hea lthy controls. Our findings show significant amounts of beta-secretase clea ved sAPP in CSF. There was no statistically significant difference in the l evels of beta-secretase cleaved sAPP between AD patients and controls. The levels of alpha-secretase cleaved sAPP and total sAPP were, however, found to be significantly lower in the AD patients than in the controls. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.