Galactose-containing glycoconjugates of the iris, the aqueous outflow passages and the cornea in capsular glaucoma

Abstract

The aim of the study was to compare galactose-containing glycoconjugates of the iris, the aqueous outflow passages and the cornea with exfoliation material in capsular glaucoma. Six formalin-fixed, paraffin-embedded human eyes with capsular glaucoma and six control eyes were studied by using a panel of 11 biotinylated lectins to galactose- and N-acetylgalactosamine-containing glycoconjugates. The Gal (beta 1-->3) GalNAc-reactive lectins peanut agglutinin (PNA) and Bauhinia purpurea alba agglutinin (BPA) and the Gal (beta 1-->4)GlcNAc-reactive lectins Ricinus communis agglutinin (RCA-I) and Phaseolus vulgaris erythroagglutinin (PHA-E) gave the strongest label with exfoliation material. Lectin binding to the iris was variable. The binding of PNA, BPA, RCA-I, Erythrina cristagalli agglutinin (ECA), PHA-E and Glycine max agglutinin (SBA) to the subendothelial region of iris blood vessels closely resembled their binding to exfoliation material. RCA-I and PHA-E bound moderately to the aqueous outflow passages. The surface of the corneal epithelium showed positive reaction with most lectins studied, but the keratocytes reacted with RCA-I and PHA-E only. Neuraminidase pretreatment generally increased the reaction intensity. The findings suggest that the glycoconjugate composition of exfoliation material in the classical locations along the anterior and posterior chamber closely resembles that in the subendothelial region of iris blood vessels.