Fig. 1
Representative images of the amyloid pathology of the autopsied human brains. The images of the left occipital lobe belong to groups with Alzheimer’s disease (AD) (A–D), cerebral amyloid angiopathy (CAA) (E–H), AD + CAA (I–L), and less amyloid β peptide (Aβ) pathology (M–P). Antibodies against Aβ17–24 (4G8, 1:5,000) (A, E, I, and M), Aβ35–40 (1A10, 1:1,000) (B, F, J, and N), and Aβ1–42 (1:100) (C, G, K, and O) were used as primary antibodies for immunohistochemistry, and Congo red staining was also performed (D, H, L, and P). In the AD group, many cored and diffuse plaques with little CAA were observed, and the majority of the Aβ pathologies consisted of Aβ42 (A–C). The cored plaques were stained with Congo red and displayed apple-green birefringence in polarized light, but diffuse plaques were not stained with Congo red (D). The small insert shows a Congo red-positive plaque with high magnification (D). In the CAA group, many brain vessels with CAA anad many diffuse plaques were observed despite the absence of cored plaques (E–G). CAA consisted of both Aβ40 and Aβ42, and diffuse plaques were stained mainly with Aβ42 (F and G). The vessels with CAA were positive for Congo red, but there were almost no lesions in the brain parenchyma (H). The small insert shows a Congo red-positive vessel at high magnification (H). In the AD + CAA group, both cored and diffuse plaques in the grey matter and many vessels with CAA were observed, and the majority of cored and diffuse plaques were stained with Aβ42 rather than Aβ40 (I-K). CAA consisted of both Aβ40 and Aβ42 (J and K). The cored plaques and vessels with CAA were stained with Congo red (L). The small insert shows Congo red-positive plaque and vessel at high magnification (L). In the less Aβ group, few diffuse plaques and vessels with CAA were observed (M–P). The scale bar represents 100 µm, and 25 µm for small inserts. AGD: argyrophilic grain disease