Fig. 2

Arteriolosclerosis pathology in the aged human brain. The present study used a 0–3 scale of severity for arteriolosclerosis pathology, which is illustrated in panels (a-d). These photomicrographs depict vascular profiles in sections of amygdala or peri-amygdaloid regions from aged individuals at various stages of arteriolosclerosis pathology. Panel (a) shows an arteriole (yellow arrow) next to a presumed venule (red arrow), which have histopathologic features within normal limits in aging, including some eosinophilic material in the vessel wall and Virchow-Robin space [*] that may be partly an artifact of fixation and embedding. Panel (b) shows an arteriole with thicker vessel wall and intact cellular constituents, but with eosinophilic material (green arrow) in the adventitia. Panel (c) depicts arteriolosclerosis of moderate severity with some “onion-skinning” of the vessel wall and extravasation of macrophages (blue arrow) in the Virchow-Robin space. Panel (d) shows severe arteriolosclerosis in two vessels that have extensive proliferation of eosinophilic material in the vessel wall, attenuation of normal arteriolar cellular contents, apparent partial occlusion of the vessel itself, and the vessels are surrounded by corpora amylacea (yellow arrow) indicating localized brain injury. The pathologic appearance of brain arteriolosclerosis is heterogeneous, particularly in the area of the brain (amygdala; panels e,f) that is at high risk for incipient TDP-43 pathology. In panel (e), one can see pathologically affected blood vessel(s) with surrounding leukocytes and eosinophilic and small slit-like profiles that appear to be cholesterol clefts in the vessel wall. In panel (f), two vessels are seen (arrows) with largely attenuated cellular contents in the vessel walls. Scale bars = 150 um (a,d); 100 um (b,c), 300 um (e), 250 um (f)