Amyloid-β peptides in plasma and cognitive decline after 1 year follow-up in Alzheimer's disease patients.

Plasma levels of amyloid-β (Aβ) peptides are potential biomarkers of early cognitive impairment and of Alzheimer's disease (AD) risk. However, the association of Aβ peptides with the rate of cognitive decline in AD patients is still unclear. In the present study we demonstrate that Aβ₁₋₄₂ 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 Aβ₁₋₄₂ 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.