Abstract
Anti-amyloid therapies for Alzheimer's disease (AD) modestly slow cognitive decline but carry significant risk of amyloid-related imaging abnormalities (ARIAs), brain swelling, and hemorrhage, particularly in apolipoprotein E ε4 carriers. Cerebral amyloid angiopathy (CAA) and vascular inflammation drive this vulnerability, highlighting the need for complementary strategies targeting upstream mechanisms of vascular injury. Cytosolic phospholipase A2 (cPLA2) regulates arachidonic acid and lysophosphatidylcholine-derived lipid signaling at the intersection of amyloid burden, oxylipin dysregulation, blood-brain barrier disruption, and neurovascular inflammation. By depleting protective membrane plasmalogens while amplifying inflammatory lipid mediators, cPLA2 creates a state of vascular vulnerability predisposing to ARIAs. This Perspective article synthesizes evidence from human, preclinical, and translational studies positioning cPLA2 as an upstream driver of CAA-related inflammation and vascular vulnerability in AD. We discuss biomarker and imaging approaches to assess cPLA2 activity in vivo and outline how targeting this pathway may enhance anti-amyloid therapy safety by mitigating ARIA risk.