Cerebrospinal Fluid from Alzheimer's Disease Patients Promotes Amyloid beta-Protein Oligomerization

Oligomers of the amyloid beta-protein (A beta) play an important role in Alzheimer's disease (AD). We hypothesized that AD patients have a central nervous system environment that promotes A beta oligomerization. We investigated the effect of cerebrospinal fluid (CSF) from 33 patients with AD and 33 age-matched, non-demented controls on oligomerization of A beta(1-40) and A beta(1-42) using the technique of photo-induced cross-linking of unmodified proteins. CSF inhibited oligomerization of both A beta(1-40) and A beta(1-42). This inhibitory effect was significantly weaker in AD patients than in non-demented controls. Our results indicate that AD patients have a CSF environment favorable for A beta oligomerization.