Advanced glycation end products in age-related macular degeneration

Objective: To investigate the localization of N-epsilon-(carboxymethyl)lysi ne (CML), a component and major immunologic epitope of advanced glycation e nd products, in aged eyes and choroidal neovascular membranes (CNVMs) surgi cally excised from eyes with age-related macular degeneration. Methods: Immunohistochemistry for CML was performed using 8 snap-frozen, su rgically excised CNVMs. Twelve eyes from patients aged 69 to 82 years and 2 donor eyes, I each from a 23-week-old fetus and 21-year-old patient, witho ut age-related macular degeneration or diabetic retinopathy were also exami ned. To determine if retinal pigment epithelial cells in CNVMs accumulate a dvanced glycation end products, cytokeratin and CML were stained in paired serial sections. Results: Soft, macular drusen and/or basal laminar and basal linear deposit s were observed in 8 of 12 aged eyes. Each case showed CML accumulation, wh ile overlying retinal pigment epithelial cells showed no accumulation in al l 12 eyes. In CNVMs, however, retinal pigment epithelial cells showed CML a ccumulation in their cytoplasm. Conclusion: The additional accumulation of advanced glycation end products in soft, macular drusen and/or retinal pigment epithelial cells may pray a role in the pathogenesis of CNVM formation in age-related macular degenerat ion. Clinical Relevance: Recently, advanced glycation end products have been fou nd to play a role both in aging changes and neovascularization. Localizatio n of advanced glycation end products in the above-mentioned tissue may lead to a better understanding of the pathogenesis of age-related macular degen eration.