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Abstract #18408 Published in IGR 3-3
Immunohistochemical and charge-specific localization of anionic constituents in pseudoexfoliation deposits on the central anterior lens capsule from individuals with pseudoexfoliation syndrome
Winkler J; Lünsdorf H; Wirbelauer C; Reinhardt DP; Laqua HGraefe's Archive for Clinical and Experimental Ophthalmology 2001; 239: 952-960
BACKGROUND: Pseudoexfoliation (PSX) syndrome is a degenerative systemic disorder that is characterized primarily by deposits of distinct fibrillar material on the surface lining the anterior and posterior chambers of the eye, and is often associated with cataract and glaucoma. Although some components of the PSX material have been identified, its precise composition remains obscure. METHODS: High-resolution scanning electron microscopy in conjunction with colloidal cationic gold labelling was used to localize anionic constituents at the surface of PSX aggregates. Transmission electron microscopy was applied for the immunocytochemical detection of glycosaminoglycans, and to monitor the charge-specific distribution of colloidal thorium dioxide and ferritin in PSX material. The specific binding of antibodies was confirmed by immunohistological staining of paraffin-embedded specimens. RESULTS: Paraffin-embedded tissue sections revealed immunoreactivity for keratan sulfate and dermatan sulfate proteoglycan within PSX material deposited on the surface of the anterior lens capsule. Post-embedding immunogold labelling of keratan sulfate demonstrated an intense label of PSX aggregates primarily associated with mature PSX fibrils, whereas dermatan sulfate proteoglycon appeared to be present in low quantities. Additionally, keratan sulfate was found at the humoral periphery of the lens capsules. To further investigate the distribution of anionic sites in PSX material, the authors used cationic colloidal tracers of different size, such as gold, thorium dioxide, and ferritin. PSX aggregates exhibited a strong negative charge, very likely resulting from glycosaminoglycan chains of proteoglycans. The density of anionic sites was higher at the interfibrillar matrix. Lens capsules associated with PSX material revealed a diminished accumulation of cationic ferritin at the humoral surfaces. CONCLUSION: Increased amounts of different glycosaminoglycans identified in PSX material suggest an important role of proteoglycans for the pathogenic pathway in PSX.
Dr J. Winkler, Department of Ophthalmology, Medical University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany. jorgw@yahoo.com
Classification:
9.4.4.1 Exfoliation syndrome (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders > 9.4.4 Glaucomas associated with disorders of the lens)