title: Accumulation of cholesterol with age in human Bruch's membrane.
abstract: OBJECTIVE
  To determine the cholesterol composition of normal human Bruch's membrane and choroid as a function of age and retinal location.
  
  
  METHODS
  Human eyes with grossly normal maculas were preserved <4 hours after donor death. Cryosections of retina and choroid from the macula and temporal equator were stained with filipin to reveal esterified (EC) or unesterified (UC) cholesterol (n = 20, 17-92 years). Filipin fluorescence in Bruch's membrane was quantified with digital microscopy. Maculas were prepared for lipid-preserving electron microscopy (n = 18, 16-87 years) and for ultrastructural analysis after lipid extraction (n = 2, 85 and 89 years). Punches of macular Bruch's membrane, 8 mm in diameter, were assayed for cholesterol content by enzymatic fluorometry (n = 10, >70 years).
  
  
  RESULTS
  EC and UC in Bruch's membrane increased with age in the macula. EC was sevenfold higher in macula than in periphery. Sixty percent of total cholesterol was esterified, and Bruch's membrane EC was 16- to 40-fold enriched relative to plasma. Solid, 100-nm-diameter particles occupied >30% of the inner collagenous layer in eyes >60 years. Cholesterol accumulated in choroidal arteries and in small age-related drusen.
  
  
  CONCLUSIONS
  Human Bruch's membrane ages like arterial intima and other connective tissues for which plasma lipoproteins are the known source of extracellular cholesterol. Age-related maculopathy and atherosclerotic cardiovascular disease may share common pathogenic mechanisms.
authors.affiliation: Departments of Ophthalmology. Physiological Optics, University of Alabama at Birmingham, Birmingham, AL 35294-0009, USA. curcio@uab.edu
authors.forename: C A
authors.initials: CA
authors.lastname: Curcio
authors.forename: C L
authors.initials: CL
authors.lastname: Millican
authors.forename: T
authors.initials: T
authors.lastname: Bailey
authors.forename: H S
authors.initials: HS
authors.lastname: Kruth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D016570:Bruch Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002784:Cholesterol / Q000378:metabolism*; D002829:Choroid / Q000378:metabolism / Q000648:ultrastructure; D005372:Filipin / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D008856:Microscopy, Fluorescence; D008875:Middle Aged
chemical_list: D005372:Filipin; D002784:Cholesterol