Arteriolar degeneration and stiffness in cerebral amyloid angiopathy are linked to Aβ deposition and lysyl oxidase

Abstract

INTRODUCTION: The morphological and molecular changes associated with the degeneration of arterioles in cerebral amyloid angiopathy (CAA) are incompletely understood. METHODS: Post mortem brains from 26 patients with CAA or neurological controls were analyzed using light-sheet microscopy, and morphological features of microvascular degeneration were quantified using surface volume rendering. Vascular stiffness was analyzed using atomic force microscopy. RESULT: Vascular smooth muscle cells (VSMCs) volume was reduced by ≈ 55% in CAA. This loss of VSMC volume correlated with increased arteriolar diameter, variability in diameter, and the volume of amyloid beta (Aβ) deposition in the vessel. Vessels with CAA were > 300% stiffer than controls. The volume of extracellular matrix cross-linking enzyme lysyl oxidase (LOX) correlated closely with vascular degenerative features. DISCUSSION: Our findings provide valuable insights into the connections among LOX, Aβ deposition, and vascular stiffness in CAA. Restoration of physiologic extracellular matrix properties in penetrating arteries may yield a novel therapeutic strategy for CAA. HIGHLIGHTS: We conducted 3D microscopy on human brains with cerebral amyloid angiopathy. We quantified features of vascular degeneration, β-amyloid, and lysyl oxidase in CAA Vascular degeneration correlated with Aβ, loss of VSMCs , and increased LOX. Arterioles with CAA were stiffer than controls in data from atomic force microscopy. Vascular extracellular matrix properties may be a therapeutic target for CAA.