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Cholesterol oxides accumulate in human cataracts
1Department of Ophthalmology and Visual Sciences, Biomedical Institute for Research in Light and Image, Coimbra University Hospitals, Portugal.
Experimental Eye Research
|June 17, 1998
Summary
This study found cholesterol oxidation products, or oxysterols, in human cataracts for the first time. These oxysterols may contribute to the membrane damage seen in cataract formation.
Area of Science:
- Ophthalmology
- Biochemistry
- Membrane Biology
Background:
- Human lens membranes have the highest cholesterol content among biological membranes.
- Cholesterol oxidation products (oxysterols) are known to cause damage, but their presence in human cataracts was previously unproven.
Purpose of the Study:
- To investigate the presence and quantify cholesterol oxides in human cataractous lenses.
- To determine if oxysterols accumulate in the lens during cataract formation.
Main Methods:
- Human clear and cataractous lenses were analyzed.
- Cholesterol oxides were extracted using solid-phase extraction (C18 cartridge).
- Quantification of cholesterol oxides was performed using gas chromatography after derivatization.
Main Results:
- Specific cholesterol oxides, including 7 beta-hydroxycholesterol and 7-ketocholesterol, were quantified in cataractous lenses.
- Clear lenses showed no detectable amounts of cholesterol oxides.
- Oxysterol formation was demonstrated in vitro in transparent lens membranes exposed to free radicals.
Conclusions:
- This study provides the first evidence of oxysterol accumulation in human cataracts.
- Oxysterols may play a role in the membrane damage associated with cataract development.