title: A comparison of N-glycan profiles in human plasma and vitreous fluid.
abstract: OBJECTIVE
  To investigate the concentration and composition of N-glycans in plasma and vitreous samples obtained from patients with non-proliferative vitreoretinal diseases.
  
  
  METHODS
  Plasma and vitreous samples were collected from 11 patients with idiopathic macular hole (MH) and 9 patients with epiretinal membrane (ERM). The samples were pretreated for enzymatic cleaving, and subsequently glycans released from proteins were captured on BlotGlyco H beads. Sialic acids were methyl-esterified. Processed glycans were tagged with aminooxy-functionalized peptide reagent (aoWR) and released from the beads, followed by detection by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The concentration and composition of N-glycans in the samples were assessed.
  
  
  RESULTS
  Concentration of N-glycans in vitreous samples (132 ± 29 pmol/100 μg protein) was significantly lower compared with those in plasma samples (714 ± 29 pmol/100 μg protein, p < 0.001). Predominant N-glycan in both plasma (39.7 ± 1.1 %) and vitreous fluid (37.2 ± 3.1 %) was identical, and the composition was presumed as [(Hex)2(HexNAc)2(NeuAc)2+ (Man)3(GlcNAc)2]. By contrast, the second-ranked N-glycan in vitreous samples (15.6 ± 1.5 %) was the seventh in plasma (2.3 ± 0.2 %).
  
  
  CONCLUSIONS
  The current data provide useful information on N-glycan profile in the vitreous fluid, which is distinct from that in the plasma.
authors.affiliation: Laboratory of Ocular Cell Biology and Visual Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Inafuku
authors.forename: Kousuke
authors.initials: K
authors.lastname: Noda
authors.forename: Maho
authors.initials: M
authors.lastname: Amano
authors.forename: Tetsu
authors.initials: T
authors.lastname: Ohashi
authors.forename: Chikako
authors.initials: C
authors.lastname: Yoshizawa
authors.forename: Wataru
authors.initials: W
authors.lastname: Saito
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kanda
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Nishimura
authors.forename: Susumu
authors.initials: S
authors.lastname: Ishida
mesh_terms: D000368:Aged; D019773:Epiretinal Membrane / Q000097:blood* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011134:Polysaccharides / Q000097:blood*; D012167:Retinal Perforations / Q000097:blood* / Q000601:surgery; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D011134:Polysaccharides