Amyloid-beta Peptides in Plasma and Cognitive Decline After 1 Year Follow-Up in Alzheimer's Disease Patients

Plasma levels of amyloid-beta (A beta) peptides are potential biomarkers of early cognitive impairment and of Alzheimer's disease (AD) risk. However, the association of A beta peptides with the rate of cognitive decline in AD patients is still unclear. In the present study we demonstrate that A beta(1-42) plasma levels show a significant correlation with the rate of cognitive decline and are significantly increased in AD patients with fast cognitive decline (decrease of Mini-Mental Status Examination (MMSE) score >= 5/year; n = 12) compared to AD patients with slow cognitive decline (decrease of MMSE score <= 4/year; n = 28), independent of baseline MMSE scores, age and cholinesterase inhibitor intake, but dependent on history of myocardial infarction and history of stroke in a multivariate analysis. These results suggest that A beta(1-42) plasma levels are associated with the rate of cognitive decline in AD patients and may be influenced by atherosclerotic vasculopathies such as stroke and myocardial infarction.