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 the human vitreous, and to investigate the correlations among the cross-links and the effects of aging and diabetes mellitus (DM) on the levels of cross-links.
  
  
  METHODS
  Forty-five vitreous samples were collected from 32 patients (32 eyes) undergoing vitrectomy for diabetic retinopathy (DM group) and from 13 patients (13 eyes) (control group) who were 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 pretreatment with SP-Sephadex.
  
  
  RESULTS
  The levels of pentosidine, pyridinoline, and deoxypyridinoline were 27.3 +/- 23.1 (mean +/- SD) pmol/mL (detectable in 45 of 45 specimens), 79.0 +/- 40.2 ng/mL (43 of 45 specimens), and 54.0 +/- 9.5 (32 of 45 specimens) ng/mL, respectively. When the vitreous samples from the DM and the control groups were compared, a significant difference (P <.05) was found in the pentosidine level but not in the levels of pyridinoline or deoxypyridinoline. No significant correlations were found between age and the cross-links. Significant correlations (P <.01) were found among the cross-links.
  
  
  CONCLUSIONS
  The results indicate that mature cross-link substances exist in the 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 they did not increase the mature cross-links.
authors.affiliation: Department of Ophthalmology, Koshigaya Hospital, Dokkyo University School of Medicine, Saitama, 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 / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D001120:Arginine / Q000031:analogs & derivatives* / Q000378:metabolism*; D003930:Diabetic Retinopathy / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D006801:Humans; D008239:Lysine / Q000031:analogs & derivatives* / Q000378:metabolism*; D008875:Middle Aged; D012016:Reference Values; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D017127:Glycation End Products, Advanced; C015484:pyridinoline; C036020:deoxypyridinoline; D001120:Arginine; C062187:pentosidine; D008239:Lysine