title: [Levels of mature cross-links and advanced glycation end product cross-links in human vitreous].
abstract: OBJECTIVE
  To determine the levels of pyridinoline and deoxypyridinoline, two mature enzymatic cross-links, and pentosidine, an advanced glycation end product (AGE) cross-link, in human vitreous and to investigate the correlations among the cross-links and the effects of aging and diabetes mellitus (DM) on the levels of the cross-links.
  
  
  METHODS
  Forty-five vitreous samples were collected from 32 eyes undergoing vitrectomy for diabetic retinopathy (DM group) and 13 eyes (control group) from age- and sex-matched patients with idiopathic macular hole or epiretinal membrane with no systemic conditions. The levels of the cross-links were determined using high-performance liquid chromatography after acid hydrolysis and pre-treatment with SP-Sephadex.
  
  
  RESULTS
  The levels of pentosidine, pyridinoline, and deoxypyridinoline were 27.3 +/- 23.1(mean +/- standrard deviation) pmol/ml (n = 45), 79.0 +/- 40.2 (mean +/- standrard deviation) ng/ml (n = 43), and 54.0 +/- 9.5 ng/ml (n = 32), respectively. When the vitreous samples from DM and the controls were compared, a significant difference (p < 0.05) was found in the level of pentosidine but not in the levels of pyridinoline or deoxypyridinoline. No significant correlations were found between age and the cross-links. Significant correlations (p < 0.01) were found among the cross-links.
  
  
  CONCLUSIONS
  The results indicate that mature cross-link substances exist in human vitreous. The results also suggest that glycation may occur in the vitreous after mature cross-links form and result in the formation of AGE cross-links. In human vitreous from patients with DM, increased levels of AGE cross-links may stabilize the formation of mature cross-links but did not increase mature cross-links.
authors.affiliation: Department of Ophthalmology, Koshigaya Hospital, Dokkyo University School of Medicine, 2-1-50 Minami-Koshigaya, Koshigaya 343-8555, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takahashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Chikuda
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Arai
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D000596:Amino Acids / Q000032:analysis*; D001120:Arginine / Q000031:analogs & derivatives* / Q000032:analysis*; D003432:Cross-Linking Reagents / Q000032:analysis*; D003920:Diabetes Mellitus / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000032:analysis*; D006801:Humans; D008239:Lysine / Q000031:analogs & derivatives* / Q000032:analysis*; D008875:Middle Aged; D014822:Vitreous Body / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D003432:Cross-Linking Reagents; D017127:Glycation End Products, Advanced; C015484:pyridinoline; C036020:deoxypyridinoline; D001120:Arginine; C062187:pentosidine; D008239:Lysine