👤 Marieke Jh Wermer

Apolipoprotein E (APOE) genotype influences the presence, course and severity of sporadic cerebral amyloid angiopathy (sCAA). We investigated the effect of the APOE ε4-allele on clinical and neuroradiological outcomes in mutation-carriers with Dutch-type hereditary (D-)CAA. Participants with D-CAA from a prospective cohort study, with data collected on history of symptomatic intracerebral hemorrhages (sICH) and vascular risk factors, underwent 3 Tesla magnetic resonance imaging (MRI) scans to assess macrobleeds, cerebral microbleeds (CMBs), cortical superficial siderosis (cSS), enlarged perivascular spaces (EPVS), white matter hyperintensity (WMH) volume and WMH multispot lesions. Global cognition was measured using Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) scores. Associations between ≥1 APOE ε4-allele and age of first sICH, time to recurrence, cognition and radiological data were analyzed with adjustments for confounders. Eighty-one participants (mean age 47 years, 54% women, 38% with sICH history) were included. The APOE ε4-allele was not associated with earlier sICH onset (median age 56 versus 57 years; p = 0.6) or time to recurrence (5.0 versus 3.9 years; p = 0.4), nor was it associated with macrobleeds (β 2.0; 95%CI 2.4- -2.7; p = 0.4), CMBs (β 2.9; 95%CI 1.0-8.9; p = 0.06), cSS (aOR 0.5; 95%CI 0.1-2.0; p = 0.3), EPVS (aOR 0.4; 95%CI 0.1-1.5; p = 0.6), WMH volume (β 6.8; 95%CI -1.9-15.4; p = ), a multispot pattern (OR 0.7; 95%CI 0.2-2.7, p = 0.6), or cognition (β -0.3; 95%CI -0.4- -0.5; p = 0.5). APOE ε4 does not affect key clinical parameters or D-CAA neuroradiological markers and therefore does not explain the large variation in disease course in D-CAA. Show less

Cerebral amyloid angiopathy (CAA) is a common age-related small vessel disease characterized by amyloid-beta (Aβ) accumulation in cortical and leptomeningeal blood vessel walls. Reduced Aβ clearance in the vasculature elevates the risk of CAA, while increasing evidence indicates that enhanced Aβ production in neurons also contributes. The impact of Aβ on the diverse cell types of the neurovascular unit (NVU)-including endothelial cells (ECs), pericytes, neurons, vascular smooth muscle cells (VSMCs), and astrocytes-remains unclear. This narrative review proposes that Aβ accumulation in NVUs during CAA drives a transcriptional response that reduces Aβ clearance while activating a neuron-specific post- transcriptional response that enhances Aβ production. Specifically, Aβ in NVUs was found to initiate a transcriptional cascade that destabilizes endothelial cells, increases blood-brain barrier permeability, and damages pericytes, ultimately inducing inflammatory and dysfunctional changes in VSMCs. These changes cause mitochondrial dysfunction and TGFβ deregulation in neurons, activating profibrotic mechanisms. Post-transcriptional regulation by microRNA networks in neurons affects Aβ processing by controlling the balance between amyloidogenic and non-amyloidogenic pathways through BACE1 and ADAM10 expression respectively. This review improves our understanding of Aβ accumulation in neurovascular units in CAA, potentially leading to better diagnostics, early biomarkers, and tools for prognosis and treatment. Show less