Plasma beta-amyloid in Alzheimer's disease and vascular disease

• Implementation of amyloid biomarkers in clinical practice would be accelerated if such biomarkers could be measured in blood. We analyzed plasma levels of A beta 42 and A beta 40 in a cohort of 719 individuals (the Swedish BioFINDER study), including patients with subjective cognitive decline (SCD), mild cognitive impairment (MCI), Alzheimer's disease (AD) dementia and cognitively healthy elderly, using a ultrasensitive immunoassay (Simoa platform). There were weak positive correlations between plasma and cerebrospinal fluid (CSF) levels for both A beta 42 and A beta 40, and negative correlations between plasma A beta 42 and neocortical amyloid deposition (measured with PET). Plasma levels of A beta 42 and A beta 40 were reduced in AD dementia compared with all other diagnostic groups. However, during the preclinical or prodromal AD stages (i.e. in amyloid positive controls, SCD and MCI) plasma concentration of A beta 42 was just moderately decreased whereas A beta 40 levels were unchanged. Higher plasma (but not CSF) levels of A beta were associated with white matter lesions, cerebral microbleeds, hypertension, diabetes and ischemic heart disease. In summary, plasma A beta is overtly decreased during the dementia stage of AD indicating that prominent changes in A beta metabolism occur later in the periphery compared to the brain. Further, increased levels of A beta in plasma are associated with vascular disease.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Neurovetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Neurosciences (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Neurologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Neurology (hsv//eng)

Keyword

CEREBROSPINAL-FLUID BIOMARKERS

MILD COGNITIVE IMPAIRMENT

WHITE-MATTER

LESIONS

A-BETA

APOLIPOPROTEIN-E

RATING-SCALE

RISK

DEMENTIA

VALIDATION

DIAGNOSIS

Publication and Content Type

ref (subject category)

art (subject category)