Galactose-containing glycoconjugates of the ciliary body and lens in capsular glaucoma: a lectin histochemical study.

BACKGROUND

This study was carried out in order to obtain information on galactose-containing glycoconjugates in the lens and ciliary body of human eyes with capsular glaucoma and thus on the etiopathogenesis of exfoliation syndrome.

METHODS

Six formalin-fixed, paraffin-embedded human eyes with capsular glaucoma and six control eyes were studied using a panel of 11 biotinylated lectins with extended binding sites to galactose- and N-acetylgalactosamine-containing glycoconjugates. Both pepsin and neuraminidase pretreatments were performed.

RESULTS

Gal(beta 1-->3)GalNAc-reactive peanut (PNA) and Bauhinia purpurea alba (BPA) agglutinins and Gal(beta 1-->4)GlcNAc GlcNAc-reactive Ricinus communis (RCA-I) and Phaseolus vulgaris (PHA-E) agglutinins reacted strongly with exfoliation material, while binding of Gal(beta 1-->4)GlcNAc-reactive Erythrina cristagalli and GalNAc-reactive soybean, Caragana arborescens, Vicia villosa, Helix pomatia (HPA) and Dolichos biflorus agglutinins was generally weak. In the nonpigmented ciliary epithelium and on the zonular fibers and lamella, at least moderate reaction was detected with PNA, BPA, RCA-I and PHA-E, and these tissues thus resembled exfoliation material in their reactivity. In contrast, the lens epithelium reacted weakly with PHA-E and HPA only, and the lens capsule was never labeled. No qualitative changes were seen after neuraminidase pretreatment.

CONCLUSION

The findings suggest that galactose- and N-acetylgalactosamine-containing glycoconjugates in exfoliation material are at least partially produced by the nonpigmented ciliary epithelium, rather than by the lens epithelium. Moreover, PNA, PBA, RCA-I and PHA-E seem to be the most suitable of the lectins tested for detection of exfoliation material in histological specimens.