Figure 2. Angiogenin localization in human eyes. Labeling of angiogenin is shown in a normal macular choroid (A), in which angiogenin is expressed on the endothelial cells of the choriocapillaris and large vessels, as well as localized to intercapillary pillars. Modest anti-angiogenin labeling is detected in some extramacular drusen (C and D, asterisks). In some donors, approximately 50% of the hard drusen showed weak immunoreactivity (C). Minor labeling of a hyaline druse (D, asterisk) was observed in an 83-year-old female with neovascular age related macular degeneration (AMD), compared to an adjacent section in which the primary antibody was omitted (E). Endothelial cells in a neovascular membrane (F) from the macula of human donor eye with advanced AMD were also reactive with anti-angiogenin antibody. The presence of angiogenin in the neovascular membrane vessels indicates that it may play a role in the pathophysiology of these cells in AMD. Controls in which primary antibodies are omitted are shown for normal tissue (B), drusen (E), and neovascular tissue (G). Scale bar represents 50 μm.