Abstract
Abstract: :
Purpose: The normal human retina contains three types of horizontal cells, H1, H2, and H3. Anti-parvalbumin (Parv) labels H1 and H2 cells, and anti-calbindin (Cal) labels H2 cells in normal monkey retina. The purpose of this study was to provide a specific marker for H1 horizontal cells in normal and diseased human retinas. Method: Immunocytochemistry was performed on normal and diseased [age related macular degeneration (AMD)] human retinas with antibodies against phosphotyrosine (PT), Parv and Cal. Results: In normal human retinas, anti-PT labels the H1 cells specifically. Anti-PT also labels microglia and blood vessels but no other retinal cell type. Anti-Parv labels the H1, H2 and H3 cells and anti-Cal labels the H2 cells. The same labeling pattern is present in the normal periphery of AMD retinas. In maculas with AMD, horizontal cell labeling is reduced with anti-Parv and anti-Cal, and absent with anti-PT. The cytoplasm of reactive Müller cells is positive with anti-PT, as are microglia that have migrated into the layer of degenerating rods and cones. Conclusion: Anti-PT is a specific marker for H1 horizontal cells in normal human retinas. In human maculas with AMD, PT immunoreactivity of H1 cells is lost, reactive Müller cells become PT-positive, and PT-positive microglia migrate into the degenerating photoreceptor layer.
Keywords: 426 horizontal cells • 308 age-related macular degeneration • 562 retinal degenerations: hereditary