title: Age-dependent changes in heparan sulfate in human Bruch's membrane: implications for age-related macular degeneration.
abstract: OBJECTIVE
  Heparan sulfate (HS) has been implicated in age-related macular degeneration (AMD), since it is the major binding partner for complement factor H (CFH) in human Bruch's membrane (BrM), and CFH has a central role in inhibiting complement activation on extracellular matrices. The aim was to investigate potential aging changes in HS quantity and composition in human BrM.
  
  
  METHODS
  Postmortem human ocular tissue was obtained from donors without known retinal disease. The HS was purified from BrM and neurosensory retina, and after digestion to disaccharides, fluorescently labeled and analyzed by reverse-phase HPLC. The HS and heparanase-1 were detected by immunohistochemistry in macular tissue sections from young and old donors, and binding of exogenously applied recombinant CCP6-8 region of CFH (402Y and 402H variants) was compared.
  
  
  RESULTS
  Disaccharide analysis demonstrated that the mean quantity of HS in BrM was 50% lower (P = 0.006) in old versus young donors (average 82 vs. 32 years). In addition, there was a small, but significant decrease in HS sulfation in old BrM. Immunohistochemistry revealed approximately 50% (P = 0.02) less HS in macular BrM in old versus young donors, whereas heparanase-1 increased by 24% in old macular BrM (P = 0.56). In young donor tissue the AMD-associated 402H CCP6-8 bound relatively poorly to BrM, compared to the 402Y form. In BrM from old donors, this difference was significantly greater (P = 0.019).
  
  
  CONCLUSIONS
  The quantity of HS decreases substantially with age in human BrM, resulting in fewer binding sites for CFH and especially affecting the ability of the 402H variant of CFH to bind BrM.
authors: Centre for Hearing & Vision Research, Institute of Human Development, University of Manchester, Manchester, United Kingdom.
authors: Tiarnan D L
authors: TD
authors: Keenan
authors: Stem Cell Glycobiology, School of Materials, University of Manchester, Manchester, United Kingdom.
authors: Claire E
authors: CE
authors: Pickford
authors: Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom Stem Cell Glycobiology, School of Materials, University of Manchester, Manchester, United Kingdom.
authors: Rebecca J
authors: RJ
authors: Holley
authors: Centre for Hearing & Vision Research, Institute of Human Development, University of Manchester, Manchester, United Kingdom Centre for Advanced Discovery and Experimental Therapeutics (CADET), University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.
authors: Simon J
authors: SJ
authors: Clark
authors: Centre for Advanced Discovery and Experimental Therapeutics (CADET), University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom Centre for Endocrinology and Diabetes, Institute of Human Development, University of Manchester, Manchester, United Kingdom.
authors: Wanchang
authors: W
authors: Lin
authors: Centre for Advanced Discovery and Experimental Therapeutics (CADET), University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom Centre for Endocrinology and Diabetes, Institute of Human Development, University of Manchester, Manchester, United Kingdom.
authors: Andrew W
authors: AW
authors: Dowsey
authors: Stem Cell Glycobiology, School of Materials, University of Manchester, Manchester, United Kingdom.
authors: Catherine L
authors: CL
authors: Merry
authors: Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
authors: Anthony J
authors: AJ
authors: Day
authors: Centre for Hearing & Vision Research, Institute of Human Development, University of Manchester, Manchester, United Kingdom.
authors: Paul N
authors: PN
authors: Bishop
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D016570:Bruch Membrane / Q000378:metabolism*; D002102:Cadaver; D056148:Chromatography, Reverse-Phase; D005260:Female; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D008268:Macular Degeneration / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011133:Polysaccharide-Lyases / Q000378:metabolism; D012160:Retina / Q000378:metabolism
chemical_list: D006497:Heparan Sulfate; D011133:Polysaccharide-Lyases; C083872:heparatinase I
keywords: AMD; Bruch's membrane; heparan sulfate