An age-related correlation between levels of beta-amyloid precursor protein and beta-amyloid in human cerebrospinal fluid.

We investigated the levels of amyloid precursor protein (APP) and beta-amyloid peptide (A beta) in the cerebrospinal fluid (CSF) from 110 individuals ranging in age from newborn to 82-years old to analyze their regulation with age. These samples were segregated into two groups; one group contained CSF samples from patients with diagnosed CNS abnormalities and the second group contained CSF samples from patients with no known CNS disorders. The presence of APP and A beta was detected in all ages and from both CSF groups. No significant difference in the average level of A beta or APP was noted from either group with a change in age. However, a positive correlation was found to exist between levels of APP and A beta in individuals 25 years and older, suggesting that APP and A beta processing in the CSF is developmentally regulated. This observation was observed for both CSF groups.