Fig 2: Morphological alteration of arteriolar walls correlates with volume of LOX.(A) β-amyloid in blue stained with Methoxy-X04 and LOX in pink, showing the overlap of β-amyloid and LOX on the arteriola, Scale bar with 100 μm. (B) The volume of LOX strongly correlated with vascular β-amyloid (C) and inversely correlated with vascular smooth muscle (VSM) volume. (D) LOX also correlated with increased vascular diameter and variability of the standard deviation of the diameter. While total volume of LOX did not correlate with tortuosity. (E) Eccentric deposits of LOX were frequently observed at sites of severe tortuosity. β-amyloid in blue stained with Methoxy-X04; VSM actin in red; LOX in pink, scale bar with 100 μm. See also supplementary video 5.

Fig 3: Atomic force microscopy (AFM) and the stiffness of arterioles.(A) Coronally sectioned profiles of arterioles from cases with CAA and without CAA were stained with thiazine red and DAPI. Cross-sections of the vessel wall were evaluated by AFM to determine tissue stiffness (example density maps across the vessel wall are shown for each condition). (B) Average stiffness in kPa for non-CAA (40.81±7.19) and CAA cases (157.4 ±6.25) are shown. (C) Increased tissue stiffness could be partly mediated by the activity of extracellular matrix crosslinking enzymes like lysyl oxidase (LOX). Confocal microscopy images of arterioles stained with collagen IV-488 (green), LOX (magenta), and β-amyloid staining with methoxy X04 (blue) shows substantial LOX deposition in CAA, especially in degenerating arterioles (rightmost image).

Fig 4: Morphological changes in vessels affected by CAA in relation to Aβ and LOX. Three‐dimensional images of a control arteriole are compared to mild, moderate, and severe CAA arterioles stained with collagen IV‐488 in green, VSMC actin‐ Cy3 in red, methoxy‐XO4 for Aβ, in blue and LOX‐ 647 in far‐red (shown in pink). A merged image of the four channels is shown in the last column, scale bar = 100 µm. A, Control with intact collagen IV and VSMCs, without methoxy‐X04 or LOX. B, Mild CAA shows a mild degeneration with patches of loss of VSMCs correlating with foci of Aβ and LOX staining. C, AD with moderate CAA shows areas of degeneration of VSMCs with deposition of Aβ and LOX correlating with twisting distortions of the arteriole. D, CAA with severe degeneration shown near‐complete loss of VSMCs with heavy deposition of Aβ and LOX, tortuosity and dilation of the arteriole. E and F, In severely degenerated arterioles with CAA, the deposits of Aβ lose their organized ring shape and look fractured at sites with aneurysmal dilation of the arteriole. Some autofluorescence is present in vessels that have ruptured or are severely dilated, likely due to residual blood products. The on‐target staining is brighter than the autofluorescence and the autofluorescence is present across a range of wavelengths. Aβ, amyloid beta; AD, Alzheimer's disease; CAA, cerebral amyloid angiopathy; LOX, lysyl oxidase; VSMC, vascular smooth muscle cell.

Fig 5: Morphological alteration of arteriolar walls correlates with volume of LOX. A, Aβ in blue stained with methoxy‐X04 and LOX in pink, showing the overlap of Aβ and LOX on the arteriole, scale bar with 100 µm. B, The volume of LOX strongly correlated with vascular Aβ (C) and inversely correlated with VSMC volume. D, LOX also correlated with increased vascular diameter and variability of the standard deviation of the diameter, while the total volume of LOX did not correlate with tortuosity. E, Eccentric deposits of LOX were frequently observed at sites of severe tortuosity. Aβ is stained in blue stained with methoxy‐X04; VSMC actin in red; LOX in pink, scale bar 100 µm. See also Video S5 and Tables S3 and S4 in supporting information. Aβ, amyloid beta; LOX, lysyl oxidase; VSMC, vascular smooth muscle cell.