BACKGROUND: Alzheimer's disease (AD) commonly accompanies cerebral amyloid angiopathy (CAA).

OBJECTIVE: We aimed to reveal associations between CAA-related brain microbleeds and cerebrospinal fluid (CSF) markers in AD patients.

METHODS: Patients with probable AD (n = 88) from consecutive patients in our memory clinic were evaluated for patient demographics, vascular risk factors, neuropsychological tests, apolipoprotein E phenotype, MRI including T2*-weighted image and fluid attenuated inversion recovery sequence, and CSF amyloid and tau markers.

RESULTS: The 88 patients with AD included 15 with microbleeds only in cortical/subcortical regions (cortical microbleeds) that could be CAA-related, 16 with microbleeds only in deep locations (deep microbleeds), 3 with microbleeds in both cortical and deep locations (mixed microbleeds), and 54 without microbleeds. The CSF levels of amyloid β-protein 1-40 (Aβ40) and amyloid β-protein 1-42 (Aβ42) were significantly lower in patients with cortical microbleeds than in those without microbleeds (p = 0.001 and p = 0.027, respectively). The result remained unchanged after adjustment for age, sex, apolipoprotein E E4 presence, and leukoaraiosis.

CONCLUSIONS: CAA-related cortical microbleeds would be associated with lower CSF levels of Aβ40 and Aβ42 in AD, reflecting the deposition of both Aβ40 and Aβ42 in the cerebrovasculature.