Basic Science and Pathogenesis.

Two broad classes of mechanisms have emerged for understanding the Amyloid-Related Imaging Abnormalities (ARIA) associated with anti-beta-amyloid immunotherapy. One set of mechanisms proposes that ARIA is driven by large-scale transfer of antibody-bound amyloid from brain parenchyma to the perivascular and vascular compartments. This class of mechanisms is indirectly supported by neuropathological evidence that immunotherapy substantially clears plaque amyloid while increasing vessel-associated amyloid, but has been difficult to directly demonstrate.

Basic Science and Pathogenesis.

Background: Alzheimer's disease (AD) related pathologies (i.e., neurofibrillary tangles [NFTs], amyloid-β plaques, and phosphorylated-TAR-DNA-binding-protein-43 [pTDP-43]) differ across sexes.

MRI free water mediates the association between diffusion tensor image analysis along the perivascular space and executive function in four independent middle to aged cohorts.

Introduction: Diffusion tensor image analysis along the perivascular space (DTI-ALPS) index was proposed for assessing glymphatic clearance function. This study evaluated DTI-ALPS as a biomarker for cerebral small vessel disease (cSVD) related vascular cognitive impairment and dementia (VCID).

Methods: Four independent cohorts were examined.

White matter free water mediates the associations between placental growth factor, white matter hyperintensities, and cognitive status.

Introduction: Placental growth factor (PlGF) may regulate cerebrovascular permeability. We hypothesized that white matter interstitial fluid accumulation, estimated via magnetic resonance imaging (MRI) free water (FW), would explain the associations between elevated PlGF, white matter hyperintensities (WMH), and cognitive impairment.

Methods: MarkVCID consortium participants ≥55 years old with plasma PlGF and brain MRI were included.

Vascular Neurology Considerations for Antiamyloid Immunotherapy: A Science Advisory From the American Heart Association.

Antibodies directed at the amyloid-β peptide offer the prospect of disease-modifying therapy for early-stage Alzheimer disease but also carry the risk of brain edema or bleeding events, collectively designated amyloid-related imaging abnormalities. Introduction of the antiamyloid immunotherapies into practice is therefore likely to present a new set of questions for clinicians treating patients with cerebrovascular disease: Which manifestations of cerebrovascular disease should preclude, or permit, antibody treatment? Is it safe to prescribe amyloid immunotherapies to individuals who require antithrombotic treatment, or to administer thrombolysis to antibody-treated individuals with acute stroke? How should severe amyloid-related imaging abnormalities be managed? This science advisory summarizes the data and key considerations to guide these challenging decisions as the medical community collects further data and experience with these groundbreaking agents.