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Major changes in human ocular UV protection with age.
L M Bova1, M H Sweeney, J F Jamie
1Australian Cataract Research Foundation, Department of Chemistry, University of Wollongong, Wollongong, NSW, Australia.
Investigative Ophthalmology & Visual Science
|January 3, 2001
Summary
Human lens coloration is linked to UV filters binding to crystallins. Glutathione may protect lenses by reacting with UV filter byproducts, with levels changing with age.
Area of Science:
- Ophthalmology
- Biochemistry
- Gerontology
Background:
- Human lens coloration increases with age.
- UV filters, such as kynurenines, accumulate in the lens.
- Glutathione is a key cellular antioxidant.
Purpose of the Study:
- To investigate the age-dependent changes in UV filters and glutathione in the human lens.
- To explore the potential protective role of glutathione against UV filter modification of crystallins.
Main Methods:
- Human lenses of varying ages were analyzed.
- UV filters and glutathione metabolites were extracted using ethanol.
- Quantification was performed using High-Performance Liquid Chromatography (HPLC).
- Correlations were examined in lens nuclear and cortical regions.
Main Results:
- UV filters (3-hydroxykynurenine, kynurenine, 3-hydroxykynurenine glucoside) decreased with age.
- Glutathionyl-3-hydroxykynurenine glucoside increased in older lenses, particularly in the nucleus.
- Reduced glutathione decreased with age, while oxidized glutathione increased in the nucleus.
Conclusions:
- Findings support a nuclear origin for specific UV filter degradation products.
- Increased modification of UV filters in older lenses may be due to diffusion barriers.
- Age-related changes in nuclear oxidized glutathione suggest impaired antioxidant capacity.