Cerebrospinal fluid concentrations of soluble amyloid beta-protein and apolipoprotein E in patients with Alzheimer's disease - Correlations with amyloid load in the brain

Objective: To compare soluble amyloid beta-protein and apolipoprotein E levels in cerebrospinal fluid (CSF) and brain extracts from patients with definite Alzheimer's disease. Setting: University medical center. Patients: Nineteen patients with definite Alzheimer's disease. Main Outcome Measures: Soluble amyloid beta-protein and apolipoprotein E levels in CSF, in neutral and low-pH brain extracts, and in formic acid-treated sections of the frontal, temporal, and cerebellar cortices, measured using enzyme-linked immunosorbent assay. Results: Soluble amyloid beta-protein and apolipoprotein E levels in CF were significantly lower in patients with congophilic angiopathy than in those without angiopathy. The levels did not correlate with the number of amyloid plaques in the neocortex. There was, however, a tendency toward an inverse correlation between the amount of amyloid beta-protein in the frontal cortex extracts and the soluble amyloid beta-protein level in CSF. Conclusion: Soluble amyloid beta-protein levels in CSF may reflect amyloid accumulation in brain blood vessels.