Abstract
Purpose: :
To analyze serum eotaxin levels in subjects with different stages of age related macular degeneration (AMD) and to study the expression of eotaxin in postmortem eyes with AMD.
Methods: :
Control subjects and those with the following four phenotypes of AMD were recruited (n= 18-20/group): AREDS stage 1 (early AMD); AREDS stage 3 (intermediate dry AMD); advanced AMD with geographic atrophy (GA); and neovascular AMD (CNV). Sera were analyzed with a Luminex-based Bio-plex system for cytokine expression. Postmortem eyes with AMD and controls were staged and processed for immunohistochemistry.
Results: :
Serum eotaxin levels were significantly elevated in all stages of AMD including GA, except for neovascular AMD (P<0.07). In post-mortem eyes with AMD, eotaxin expression was enhanced in retinal pigment epithelial and choroidal endothelial cells in early AMD, GA and CNV, and robustly expressed in neovascular endothelium. Eotaxin accumulated within the layers of basal linear/laminar deposits in all stages of AMD. Eotaxin was also detected in the neurosensory retina, with no discernable difference in staining between control and AMD specimens.
Conclusions: :
Eotaxin is constitutively expressed in the neural retina. Elevated serum levels and enhanced expression of eotaxin are closely associated with AMD including GA. The robust expression of eotaxin in the neovascular endothelium, and lack of significantly elevated levels in the sera of subject with CNV suggests that local production of eotaxin by neovascular endothelial cells is an important contributor to neovascular AMD.
Keywords: age-related macular degeneration • cytokines/chemokines • inflammation