title: Lectin binding in normal, keratoconus and cross-linked human corneas.
abstract: In this study the characterization of various types of sugar residues in normal, keratoconus and cross-linked human corneas was performed using immunohistochemical localization with lectins. Corneal samples were collected and divided into three groups: (1) normal corneas from cadavers; (2) keratoconic corneal buttons; (3) keratoconic corneal buttons treated with cross-linking. A series of lectins including: DBA, SBA, PNA, ConA, WGA, UEA I, GNA, DSA, MAA, SNA, were used in combination with chemical and enzymatic treatments. Compared with the normal corneas, N-acetyl-D-glucosamine increased in the keratoconus corneas. L-fucose increased and/or appeared in the keratoconus and the cross-linked corneas. N-acetyl-D-galactosamine was more abundant in the epithelium of keratoconus corneas, but was lacking in the keratoconus and cross-linked endothelium. D-galactose-(β1-4)-N-acetyl-D-glucosamine was absent in the whole stroma of the keratoconus corneas and in the deep layers of the cross-linked ones. Sialic acids increased in the keratoconus corneas and decreased in the cross-linked ones. These results showed altered glycosylation in the keratoconic corneas and partially similar glycosylation in the cross-linked corneas, compared to the normal ones. This suggests a role played by sugar residues in maintaining the corneal structure. The changes could be related to structural alterations in keratoconus. The present findings contribute to our understanding of the effect of cross-linking treatment of keratoconic corneas in therapeutic attempts to re-establish the normal corneal structure.
authors.affiliation: Department of Oto-Neuro-Ophthalmological Surgical Sciences, Eye Clinic, University of Florence, Viale Morgagni 85, Florence, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Mencucci
authors.forename: Mirca
authors.initials: M
authors.lastname: Marini
authors.forename: Gherardo
authors.initials: G
authors.lastname: Gheri
authors.forename: Debora
authors.initials: D
authors.lastname: Vichi
authors.forename: Erica
authors.initials: E
authors.lastname: Sarchielli
authors.forename: Laura
authors.initials: L
authors.lastname: Bonaccini
authors.forename: Stefano
authors.initials: S
authors.lastname: Ambrosini
authors.forename: Giorgia D
authors.initials: GD
authors.lastname: Zappoli Thyrion
authors.forename: Iacopo
authors.initials: I
authors.lastname: Paladini
authors.forename: Gabriella B
authors.initials: GB
authors.lastname: Vannelli
authors.forename: Eleonora
authors.initials: E
authors.lastname: Sgambati
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D003315:Cornea / Q000378:metabolism* / Q000503:physiopathology; D006031:Glycosylation; D006801:Humans; D007150:Immunohistochemistry; D007640:Keratoconus / Q000378:metabolism* / Q000503:physiopathology*; D037102:Lectins / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D002241:Carbohydrates; D037102:Lectins