title: Glycomic characterization of basal tears and changes with diabetes and diabetic retinopathy.
abstract: As a secreted fluid, the state of tear glycosylation is particularly important in the role of immunity of the ocular surface. Tears are a valuable source of non-invasive biomarkers for disease and there are continued efforts to characterize their components thoroughly. In this study, a small volume of basal tears (5 μL) was collected from healthy controls, patients with diabetes without retinopathy and patients with diabetes and retinopathy. The detailed N- and O-linked tear protein glycome was characterized and the relative abundance of each structure determined. Of the 50 N-linked glycans found, 89% were complex with 50% containing a bisecting N-acetylglucosamine, 65% containing a core fucose whilst 33% were sialylated. Of the 8 O-linked glycans detected, 3 were of cores 1 and 5 of core 2 type, with a majority of them being sialylated (90%). Additionally, these glycan structures were profiled across the three diabetic disease groups. Whilst the higher abundant structures did not alter across the three groups, only five low abundance N-linked glycans and 1 O-linked glycan did alter with the onset of diabetes mellitus and diabetic retinopathy (DR). These results suggest the conservation of glycan types on basal tear proteins between individuals and point to only small changes in glycan expression on the proteins in tears with the development of diabetes and DR.
authors.affiliation: Biomolecular Frontiers Research Centre, Department of Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, Building E8C Room 307, Sydney, NSW 2109, Australia.
authors.forename: Terry
authors.initials: T
authors.lastname: Nguyen-Khuong
authors.affiliation: Biomolecular Frontiers Research Centre, Department of Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, Building E8C Room 307, Sydney, NSW 2109, Australia.
authors.forename: Arun V
authors.initials: AV
authors.lastname: Everest-Dass
authors.affiliation: Biomolecular Frontiers Research Centre, Department of Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, Building E8C Room 307, Sydney, NSW 2109, Australia.
authors.forename: Liisa
authors.initials: L
authors.lastname: Kautto
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Zhenjun
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Mark D P
authors.initials: MD
authors.lastname: Willcox
authors.affiliation: Biomolecular Frontiers Research Centre, Department of Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, Building E8C Room 307, Sydney, NSW 2109, Australia nicki.packer@mq.edu.au.
authors.forename: Nicolle H
authors.initials: NH
authors.lastname: Packer
mesh_terms: D016022:Case-Control Studies; D003930:Diabetic Retinopathy / Q000378:metabolism*; D006801:Humans; D011134:Polysaccharides / Q000032:analysis*; D013666:Tears / Q000737:chemistry*
chemical_list: D011134:Polysaccharides
keywords: basal tears; diabetes; diabetic retinopathy; glycomics; tear film