Figure 1.

Confocal images representative of double-fluorescence immunohistochemical study of astrocytes with ALDH1L1 (green) (A–D) and GFAP (red) (E–H); merged images are also shown (I–L). Representative images from four cases are shown: one nondemented control subject (A, E, and I), and three AD patients with 5 years (B, F, and J), 12 years (C, G, and K), and 19 years (D, H, and L) of clinical illness. The majority of astrocytes in the nondemented individual were GFAP⁻ (resting astrocytes), as seen in the merged image (I), whereas astrocytes in the AD cortex displayed a reactive phenotype with GFAP-immunoreactivity that was associated with the duration of the illness (J, K, and L). Disease-related cortical atrophy produced an increase in the density of astrocytes (green) (A versus D). Scale bar = 50 μm.