title: Changes in the collagenous matrix of the aging human lamina cribrosa.
abstract: OBJECTIVE
  The age-related changes in the biochemical composition of the collagenous matrix of the human lamina cribrosa were investigated.
  
  
  METHODS
  An age range (3 weeks to 92 years old) of human laminae cribrosae, dissected free of any surrounding structures which contained collagen, were analysed for collagen solubility (n = 58) total collagen content (n = 46), proportion of collagen types (n = 38), and collagen cross linking (n = 30), using hydroxyproline analysis, scanning densitometry of peptides after cyanogen bromide digestion, and high performance liquid chromatography, respectively.
  
  
  RESULTS
  Age-related changes included an increase in total collagen and a decrease in the proportion of type III collagen within the lamina cribrosa. The collagen cross link pyridinoline was present at low levels, but demonstrated no trend with age. An age-related increase was found in pentosidine, an advanced glycation product.
  
  
  CONCLUSIONS
  These changes in collagen composition imply that the mechanical properties of the lamina cribrosa are altered, resulting in a stiffer, less resilient structure with age. Such alterations in structure may contribute to the increased susceptibility of the elderly to axonal damage in chronic open angle glaucoma.
authors.affiliation: Department of Ophthalmology, University of Bristol, Bristol Eye Hospital, Bristol.
authors.forename: J
authors.initials: J
authors.lastname: Albon
authors.forename: W S
authors.initials: WS
authors.lastname: Karwatowski
authors.forename: N
authors.initials: N
authors.lastname: Avery
authors.forename: D L
authors.initials: DL
authors.lastname: Easty
authors.forename: V C
authors.initials: VC
authors.lastname: Duance
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000596:Amino Acids / Q000032:analysis; D001120:Arginine / Q000031:analogs & derivatives / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D003094:Collagen / Q000032:analysis*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008239:Lysine / Q000031:analogs & derivatives / Q000032:analysis; D008875:Middle Aged; D012161:Retinal Artery / Q000737:chemistry; D012590:Sclera / Q000737:chemistry*; D012995:Solubility
chemical_list: D000596:Amino Acids; C015484:pyridinoline; D003094:Collagen; D001120:Arginine; C062187:pentosidine; D008239:Lysine