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Oxindolealanine in age-related human cataracts
Lilia A Rousseva1, Elizabeth R Gaillard, David C Paik
1Department of Ophthalmology, Columbia University, New York, NY 10032, USA.
Experimental Eye Research
|October 16, 2007
Summary
Tryptophan oxidation product oxindolealanine (OIA) is elevated in human cataractous lenses. This study quantifies OIA levels, implicating tryptophan oxidation in cataract development.
Area of Science:
- Biochemistry
- Ophthalmology
- Analytical Chemistry
Background:
- Human lens aging involves structural and chemical modifications.
- Tryptophan oxidation is a potential contributor to cataractogenesis.
- Oxindolealanine (OIA) is an early product of tryptophan oxidation.
Purpose of the Study:
- To investigate structural and quantitative changes in the human lens due to tryptophan oxidation.
- To detect and quantify oxindolealanine (OIA) in cataractous human lenses.
- To compare OIA levels in different regions of the lens and between cataractous and control lenses.
Main Methods:
- Mass spectrometry (MS) for detection and confirmation of OIA.
- High-performance liquid chromatography with photodiode array (HPLC-PDA) detection for OIA quantification.
- Hydrolysis and lyophilization of human and calf lenses for sample preparation.
Main Results:
- Oxindolealanine (OIA) was detected and confirmed in human cataractous lenses.
- OIA levels were significantly higher in the nucleus compared to the cortex of cataractous lenses (nucleus/cortex ratio > 1.5).
- Human cataractous lenses showed a 4.6-fold increase in OIA compared to calf lenses (controls).
Conclusions:
- OIA levels are elevated in human cataractous lenses.
- Tryptophan oxidation, leading to OIA formation, is implicated in human cataract development.
- Quantitative analysis supports the role of OIA in lens opacification.
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