Abstract
Purpose: :
Angiogenin is a 14kDa protein with roles in RNA metabolism and endothelial cell proliferation. In order to assess whether angiogenin is associated with pathologic neovascularization in AMD, we evaluated the localization of this protein in the retina and choroid of normal eyes and eyes with choroidal neovascular membranes.
Methods: :
Frozen sections of the retina, RPE and choroid of human donor eyes were collected and utilized for immunohistochemistry with an antibody directed against angiogenin. Dual labeling was performed with antibodies directed against intercellular adhesion molecule–1 (ICAM–1) to visualize the choroidal vasculature. Sections from 4 eyes with choroidal neovascular membranes were also assessed.
Results: :
In the neural retina, immunoreactivity was primarily noted in the nerve fiber layer and in most blood vessels. In the choroid, smooth muscle cells and a population of fibroblasts were labeled. In addition, a subset of choroidal capillaries in normal eyes were labeled. In eyes with choroidal neovascularization, basal laminar deposits showed patchy labeling and vascular elements of choroidal neovascular membranes were strongly labeled with angiogenin antibodies.
Conclusions: :
Angiogenin is present in the normal choroid and in choroidal neovascular membranes. The observation that a subset of choriocapillaris vessels express angiogenin may suggest that angiogenin plays a role in normal choroidal vascular remodeling, as well as in pathologic neovascularization.
Keywords: choroid: neovascularization • age-related macular degeneration • immunohistochemistry