Plasma N-glycan signature as biomarker for primary open angle glaucoma

Primary open angle glaucoma (POAG) is a major subtype of glaucoma and a leading cause of irreversible visual impairment and blindness worldwide, but with elusive pathogenesis. Here we aimed to delineate the N-glycan profile in the plasma samples of POAG patients and compare to that of the mild senile cataract subjects. Fasting peripheral whole blood was collected from 44 unrelated Han Chinese POAG patients and 39 mild senile cataract subjects. The plasma samples were isolated and subjected to the N-glycan profiling analysis by high throughput fluorophore-assisted capillary gel electrophoreses in an DNA sequencer. In total, 21 major asialo N-glycan peaks were observed in the plasma samples of the POAG patients and cataract subjects through the capillary gel electrophoresis analysis. Relative peak height proportions of Peak III, VIII, and X showed significant differences in the POAG patients as compared to the cataract subjects, and combined Peak III, VIII, and X achieved an AUC of 0.792. Linear correlation analysis revealed a negative correlation of Peak X with mean deviation of visual field in the POAG patients. Notably, sex-specific N-glycan differences were observed. Lectin blotting demonstrated higher level of core fucosylation on the plasma immunoglobulin G of the POAG patients. In summary, this study revealed the N-glycan profiles in the plasma samples of POAG patients. The plasma N-glycan signature can be a potential novel biomarker for POAG.