Cerebral microbleeds in early Alzheimer's disease

Area of Science:

• Neurology
• Neuroimaging
• Biochemistry

Background:

• Cerebral microbleeds (CMB) and vascular damage are increasingly recognized in early Alzheimer's disease (AD).
• Understanding the relationship between neuropsychological profiles, vascular pathology, and AD biomarkers is crucial for early diagnosis and intervention.

Purpose of the Study:

• To investigate the association between cerebral microbleeds (CMB), neuropsychological profiles (amnestic vs. non-amnestic), and MRI-detected vascular damage in early Alzheimer's disease.
• To explore the role of blood-brain barrier (BBB) dysfunction and cerebrospinal fluid (CSF) amyloid-beta (Aβ) ratios in patients with CMB.

Main Methods:

• 136 outpatients with cognitive decline underwent MRI (1.5 and 3 T) and comprehensive neuropsychological assessments.
• Cerebrospinal fluid (CSF) was analyzed for tau, phosphorylated tau, Aβ1-40, Aβ1-42, and albumin.
• Logistic regression analysis identified predictive factors for CMB.

Main Results:

• Cerebral microbleeds (CMB) were present in 45% of patients, predominantly in those with an amnestic profile.
• Patients with CMB showed significantly lower Aβ1-40/42 ratios and evidence of BBB dysfunction (elevated CSF-serum albumin ratio).
• Age, white matter hyperintensities (WMH) score, and albumin ratio were significant predictors of CMB.

Conclusions:

• Cerebral microbleeds (CMB) in early Alzheimer's disease are associated with blood-brain barrier (BBB) dysfunction and altered amyloid-beta (Aβ) metabolism.
• Neuropsychological profile, particularly non-amnestic, may influence the relationship between CMB and Aβ ratios.
• Predictive factors for CMB include age, WMH, and BBB integrity, highlighting their importance in AD pathogenesis.