The Amyloid-β Oligomer Count in Cerebrospinal Fluid is a Biomarker for Alzheimer's Disease

Recent studies indicate that small amyloid-beta peptide (A beta) oligomers are the major toxic species responsible for development and progression of Alzheimer's disease (AD). Therefore, we suggest that the number of A beta oligomers in body fluids is the most direct and relevant biomarker for AD. Determination of the A beta oligomer content of cerebrospinal fluid (CSF) samples from 14 AD patients and 12 age-matched controls revealed a clear distinction between both groups. All samples of the control group showed homogenously low numbers of A beta oligomers, while the samples of the AD group exhibited significantly higher levels of A beta oligomers. The A beta oligomer numbers correlated with the patients' Mini-Mental State Examination scores. This indicates that the quantity of A beta oligomers in CSF reflects the severity of the disease and that A beta oligomers play a crucial role in AD pathology and in turn can be used as a diagnostic biomarker.