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Abstract #10285 Published in IGR 6-1
Changes in HNK-1 epitope and collagen type IX in the aqueous humour of patients with pseudoexfoliation syndrome
Gartaganis SP; Georgakopoulos CD; Assouti M; Mela EK; Exarchou A; Giannelou I; Gotsis SS; Ziouti N; Vynios DH; Tripathi BJCurrent Eye Research 2004; 28: 5-10
PURPOSE: To investigate alterations in the proteoglycan (PG) and glycosaminoglycan (GAG) content of the aqueous humor in patients with pseudoexfoliation syndrome (PEX). MATERIAL AND METHODS: Aqueous humor samples were obtained during cataract surgery from 19 patients with PEX features and 23 age-matched normal controls. Protein and IgG were quantified densitometrically after their electrophoretic separation. Collagen type IX, 3-sulphoglucuronic acid (HNK-1 epitope), biglycan and heparan sulphate proteoglycans were detected in Western and dot blots using specific monoclonal antibodies (MAbs). Immunochemical analysis was performed in native aqueous humor or after degradation of the glycosaminoglycans with chondroitinases. RESULTS: Degradation of the samples with chondroitinases ABC, AC and B revealed that, in the aqueous humor of PEX eyes, collagen type IX and biglycan had a more dermatan sulphate than normal eyes. In addition, more HNK-1 epitope was observed in PEX eyes, which after similar enzymatic treatment was found to be located mainly in dermatan sulphate sequences. 3-sulphoglucuronic acid was a constituent of the GAG chains of the collagen type IX. It was found that the electrophoretic mobility of the bands of collagen type IX and HNK-1 epitope was exactly the same in the aqueous humor of both normal and PEX samples; both migrated as four bands at 120, 113, 92.6 and 56 kDa. PGs bearing heparan sulphate were only found in normal samples. No other PGs were detected. CONCLUSIONS: Because no significant difference was observed in the concentration of albumin and IgG in PEX and normal samples, the blood-aqueous barrier was probably not significantly compromised in PEX patients with cataract but without open-angle glaucoma. These results support the hypothesis that the pathogenesis of PEX can be linked to the disturbed metabolism of GAGs and PGs.
Dr. S.P. Gartaganis, Department of Ophthalmology, University of Patras Medical School, Patras, Rion, Greece. s.gartag@med.upatras.gr
Classification:
2.6.3 Compostion (Part of: 2 Anatomical structures in glaucoma > 2.6 Aqueous humor dynamics)
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)
