Abstract
Purpose: :
Drusen contain mediators of inflammation, including amyloid beta, and components of the complement cascade (including the membrane attack complex, C5b–9). The purpose of this study is to determine the spatial relationship of activated microglia, amyloid precursor protein and C5b–9 in normal donor eye tissue.
Methods: :
Immunohistochemical methods were used to identify APP, C5b–9 and activated microglia in cryostat sections of the posterior poles from normal donor eyes, less than 55 yrs (N= 15) or greater than 70 yrs of age (N=15).
Results: :
Immunohistochemical staining patterns were distinct for each antibody. APP immunoreactivity was present in cytoplasmic compartment of the RPE and retinal ganglion cells. C5b–9 immunoreactivity was present in the matrix surrounding the choriocapillaris. RCA lectin binding was present in activated microglia. None of the 15 eyes less than 55 yrs of age exhibited strong C5b–9 staining, while 2 of 15 (2/15 or 13%) exhibited mild to moderate C5b–9 immunostaining. In the group of eyes greater than 70 yrs of age, 3 of 15 eyes exhibited strong, while 4 of 15 eyes exhibited mild to moderate immunostaining for C5b–9 (total 7/15 or 46%).
Conclusions: :
Preliminary data suggest that C5b–9 immunoreactivity in the choriocapillaris zone increases with age in normal, donor eyes. The relationship between C5b–9, amyloid precursor protein and activated microglia in human donor eyes will be discussed.
Keywords: age-related macular degeneration • inflammation • drusen