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T. Khan, I. D. Navarro, R. Kastury, P. Gonzalez, P. Challa; Analysis of LOXL1 Expression in Lens Capsule Tissue Specimens From Individuals With Pseudoexfoliation and Primary Open-Angle Glaucoma. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2166.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate LOXL1 expression levels in freshly collected lens capsules from pseudoexfoliation syndrome (PEX), pseudoexfoliation glaucoma (PEXG), primary open angle glaucoma (POAG), and cataract control individuals. To study the effects of four glaucoma drugs on LOXL1 expression in immortalized and primary human lens epithelial cell cultures. The lens is a major site of PEX production and deposition.
IRB approval was obtained prior to starting the study and informed consent was obtained from all participating individuals. Lens capsules were collected at the time of cataract surgery. Controls were matched to age, sex, and ethnicity. Total RNA was isolated from individual lens capsule samples and reverse transcript PCR was performed on each sample. Real-time PCR was performed using the beta-actin gene as a control. Cell cultures were grown to confluence and then treated with one of four glaucoma drugs once daily with simultaneous change of medium. Controls were not treated with any drug and media changed in the same manner. After one week of treatment, cells were harvested and total RNA isolated. Reverse transcript PCR was performed on each group of cells using LOXL1 and beta-actin primers.
32 samples were analyzed (7 PEX, 7 PEXG, 8 POAG, and 10 control). LOXL1 expression was detected in the lens capsule specimens from all four groups. Gene expression was measured and normalized to control tissue expression. The results demonstrated significant differences between the control and PEXG; control and POAG; PEX and PEXG; and PEX and POAG. No significant difference was observed between the control and PEX or between PEXG and POAG. Real-time semi-quantitative PCR revealed no significant difference in LOXL1 gene expression between the un-treated control groups and the 1:1000 drug:media groups. At ten-fold higher concentrations (1:100 drug:media), brinzolamide, timolol maleate, and latanoprost showed a mild increase in LOXL1 expression relative to the control. This effect was not observed with brimonidine tartrate.
These results establish that LOXL1 expression is markedly reduced in lens capsule specimens from both PEXG and POAG individuals. Decreases in LOXL1 expression observed in PEXG and POAG are not attributable to a drug-related etiology. Although LOXL1 polymorphisms are not associated with POAG, this data suggests that LOXL1 may play a yet uncharacterized role in the two disorders.
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