Cerebrospinal Fluid Biomarkers and Amyloid-ß Elimination from the Brain in Cerebral Amyloid Angiopathy-Related Inflammation.

ABSTRACT

BACKGROUND: Cerebrospinal fluid (CSF) biomarkers in patients with cerebral amyloid angiopathy-related inflammation (CAA-ri) have demonstrated inconsistent results. OBJECTIVE: We investigated the relationship between CSF amyloid-ß protein (Aß) and vascular pathological findings to elucidate the mechanisms of Aß elimination from the brain in CAA-ri. METHODS: We examined Aß40 and Aß42 levels in CSF samples in 15 patients with CAA-ri and 15 patients with Alzheimer's disease and cerebral amyloid angiopathy (AD-CAA) using ELISA as a cross-sectional study. Furthermore, we pathologically examined Aß40 and Aß42 depositions on the leptomeningeal blood vessels (arteries, arterioles, and veins) using brain biopsy samples from six patients with acute CAA-ri and brain tissues of two autopsied patients with CAA-ri. RESULTS: The median Aß40 and Aß42 levels in the CSF showed no significant difference between pre-treatment CAA-ri (Aß40, 6837 pg/ml; Aß42, 324 pg/ml) and AD-CAA (Aß40, 7669 pg/ml, p = 0.345; Aß42, 355 pg/ml, p = 0.760). Aß40 and Aß42 levels in patients with post-treatment CAA-ri (Aß40, 1770 pg/ml, p = 0.056; Aß42, 167 pg/ml, p = 0.006) were lower than those in patients with pre-treatment CAA-ri. Regarding Aß40 and Aß42 positive arteries, acute CAA-ri cases showed a higher frequency of partially Aß-deposited blood vessels than postmortem CAA-ri cases (Aß40, 20.8% versus 3.9%, p = 0.0714; Aß42, 27.4% versus 2.0%, p = 0.0714, respectively). CONCLUSION: Lower levels of CSF Aß40 and Aß42 could be biomarkers for the cessation of inflammation in CAA-ri reflecting the recovery of the intramural periarterial drainage pathway and vascular function.