Age-related lipid oxidation in human lenses.
OBJECTIVE
To quantify age-related changes in products of lipid oxidation in human lenses and to relate these changes to membrane hydrocarbon chain structure. Deviation from a well-defined membrane-lipid composition and structure could result in alterations in membrane function and disruption of the homeostasis of the cell.


METHODS
Infrared spectroscopy was used to detect lipid compositional and structural changes in human lens membranes associated with age and cataracts.


RESULTS
Lipid oxidation increased linearly threefold relative to total phospholipids in subjects ranging in age between 1 and 85 years, as was evident by increases in trans double bonds, lipid carbonyls, and secondary products. There was no statistical difference between the levels of lipid oxidation in the cortex or nucleus. Lipid hydrocarbon chain order (rigidity) increased from approximately 40% at birth to 70% at 80 years of age. Changes in lipid order correlated with changes in the relative content of membrane phosphatidylcholine and sphingomyelin, and with the level of lipid oxidation.


CONCLUSIONS
Lipid oxidation increased linearly and uniformly throughout the human lens with age. The change in lipid oxidation with age correlated to a change in lipid order.
Borchman
D
D
Department of Ophthalmology and Visual Sciences, University of Louisville, Kentucky 40202, USA.
Yappert
M C
MC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007908:Lens, Crystalline / Q000737:chemistry / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000502:physiology*; D008054:Lipid Peroxides / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008315:Malondialdehyde / Q000032:analysis; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism*; D008875:Middle Aged; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism; D013055:Spectrophotometry, Infrared
D008054:Lipid Peroxides; D008563:Membrane Lipids; D010743:Phospholipids; D008315:Malondialdehyde