title: Mature enzymatic collagen cross-links, hydroxylysylpyridinoline and lysylpyridinoline, in the aging human vitreous.
abstract: OBJECTIVE
  The vitreous body of the human eye undergoes progressive morphologic changes with aging. Since the enzymatic collagen cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) are known to be important for the integrity of the collagen matrix, the presence in the vitreous on aging was studied.
  
  
  METHODS
  Vitreous bodies (VBs; n = 143) from 119 donors (age 4-80 years; mean +/- SD, 54.3 +/- 17.0 years) were carefully dissected. After weighing and freeze-drying, all samples were analyzed by high performance liquid chromatography. Left and right eyes of 24 donors were compared and, for age-related phenomena, 119 single eyes were used.
  
  
  RESULTS
  Within one donor, no significant differences were found between left and right eyes. On aging, VB wet weight (4.42 +/- 0.84 g) accumulates until 35 years and decreases thereafter. Collagen content (0.30 +/- 0.14 mg), HP per triple helix (TH; 0.55 +/- 0.18), and (HP plus LP)/TH (0.61 +/- 0.19) increase until 50 years followed by a decrease, whereas LP/TH (0.057 +/- 0.018) accumulates until 50 years and remains constant thereafter. The ratio between HP and LP (range, 0.42-31.0; median, 10.0) is constant over time.
  
  
  CONCLUSIONS
  The accumulation of enzymatic collagen cross-links until 50 years is consistent with collagen maturation and possible collagen synthesis in the human vitreous body. The decline of collagen cross-links after 50 years is consistent with collagen breakdown.
authors: Departments of Ophthalmology,University of Groningen, Groningen, The Netherlands. t.l.ponsioen@ohk.umcg.nl
authors: Theodorus L
authors: TL
authors: Ponsioen
authors: Marielle van
authors: Mv
authors: Deemter
authors: Rudolf A
authors: RA
authors: Bank
authors: Johanna M
authors: JM
authors: Snabel
authors: Gerrit S
authors: GS
authors: Zijlstra
authors: Roelofje J
authors: RJ
authors: van der Worp
authors: Johanna M M
authors: JM
authors: Hooymans
authors: Leonoor I
authors: LI
authors: Los
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000596:Amino Acids / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D003094:Collagen / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D000596:Amino Acids; C015484:pyridinoline; C036020:deoxypyridinoline; D003094:Collagen