Characterization of peroxidized lipids in Bruch's membrane.
OBJECTIVE
To determine if peroxidized lipids occur in Bruch's membrane isolates and to characterize the type present in human necropsy specimens.


METHODS
Bruch's membrane isolates from eye bank eyes obtained from 13 white donors were homogenized. Measurement of peroxidized lipids was done with the fluorometric thiobarbituric acid assay and high pressure liquid chromatography.


RESULTS
Bruch's membrane isolate homogenates contained native unsaturated fatty acids and peroxidized lipids in a ratio of about 200:1. The amount of thiobarbituric acid reacting substances increased exponentially with age. The peroxidized lipids identified in Bruch's membrane isolates were derived from long chain polyunsaturated fatty acids, particularly docosahexaenoic acid and linolenic acid, which are normally found in the photoreceptor outer segments.


CONCLUSIONS
Lipids are known to accumulate in Bruch's membrane, an acellular layer with no known intrinsic mechanisms to combat lipid peroxidation. In related studies, lipid peroxides have been shown to induce neovascularization by inducing expression of a cascade of angiogenic cytokines. This is the first study to show that lipid peroxides, biological molecules that have the potential to incite new vessel growth, occur in Bruch's membrane. The increase in amount of peroxidized lipids with age, combined with their vasogenic potential, suggests that peroxidized lipids may play a role in the etiology of age-related macular degeneration, particularly choroidal neovascularization.
Spaide
R F
RF
LuEsther T. Mertz Retina Research Laboratory, Manhattan Eye, Ear, and Throat Hospital, New York, USA.
Ho-Spaide
W C
WC
Browne
R W
RW
Armstrong
D
D
D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism; D016718:Arachidonic Acid / Q000032:analysis; D016570:Bruch Membrane / Q000737:chemistry*; D002102:Cadaver; D002851:Chromatography, High Pressure Liquid; D004281:Docosahexaenoic Acids / Q000032:analysis; D005125:Eye Banks; D005470:Fluorometry; D006801:Humans; D019787:Linoleic Acid / Q000032:analysis; D008054:Lipid Peroxides / Q000032:analysis*; D008875:Middle Aged; D010786:Photoreceptor Cells / Q000737:chemistry; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014019:Tissue Donors
D008054:Lipid Peroxides; D017392:Thiobarbituric Acid Reactive Substances; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid; D019787:Linoleic Acid