Antioxidant enzyme in the macular retinal pigment epithelium of eye with neovacular age-related macular degeneration Original Reearch Article

PURPOE: To tet the hypothei that neovacular age-related macular degeneration i related to oxidative tre involving the macular retinal pigment epithelium. Thi tudy invetigated, a a function of age, level of enzyme that defend tiue againt oxidative tre in the macular retinal pigment epithelium of human eye with thi dieae. METHOD: urgical pecimen of macular choroidal neovacular membrane from eye with age-related macular degeneration and the macular region of whole donor eye with neovacular age-related macular degeneration or without evident ocular dieae were tudied by quantitative electron microcopic immunocytochemitry with colloidal gold–labeled econd antibodie. Relative level in retinal pigment epithelium cell cytoplam and lyoome were determined of five enzyme believed to protect cell from oxidative tre, a well a level of the retinal pigment epithelium marker cytoplamic retinaldehyde-binding protein, for comparion with the enzyme. REULT: Copper, zinc uperoxide dimutae immunoreactivity increaed and catalae immunoreactivity decreaed with age in cytoplam and lyoome from macular retinal pigment epithelium cell of normal eye and eye with age-related macular degeneration. Cytoplamic retinaldehyde-binding protein immunoreactivity howed no ignificant relationhip to age or the preence of neovacular age-related macular degeneration. Glutathione peroxidae immunoreactivity wa abent from human retinal pigment epithelium cell. Both heme oxygenae-1 and heme oxygenae-2 had highly ignificantly greater immunoreactivity in retinal pigment epithelium cell lyoome than in cytoplam, differing from the much greater cytoplamic immunoreactivity of the other protein tudied. Thi immunoreactivity decreaed with age, particularly in the lyoome of retinal pigment epithelium cell from eye with neovacular age-related macular degeneration. Thee decreae were of borderline ignificance (P = .067 for heme oxygenae-1; P = .12 for heme oxygenae-2) when eye with age-related macular degeneration were compared with normal eye by multivariable logitic regreion. CONCLUION: The high heme oxygenae-1 and heme oxygenae-2 lyoomal antigen level in macular retinal pigment epithelium cell of eye with neovacular age-related macular degeneration ugget that oxidative tre caue a pathologic upregulation of thee enzyme. Increaed lyoomal dipoal may indicate that the reparative function of thee enzyme are accompanied by deleteriou effect, neceitating their rapid removal from the cell. The much higher heme oxygenae-1 and heme oxygenae-2 antigen level in macular retinal pigment epithelium cell from younger individual ugget that protective mechanim againt oxidation and, hence, preumably to the development of age-related macular degeneration, decreae with age.