Serum and aqueous xanthine oxidase levels, and mRNA expression in anterior lens epithelial cells in pseudoexfoliation

The aim of this study was to determine serum and aqueous xanthine oxidase (XO) levels, and mRNA expression in anterior lens epithelial cells in pseudoexfoliation (PEX). In this prospective study, serum, aqueous and anterior lens capsules were taken from 21 patients with PEX and 23 normal subjects who had undergone routine cataract surgery. Serum and aqueous XO levels were analyzed using the colorimetric method. mRNA expression of XO in anterior lens epithelial cells was evaluated using reverse transcription polymerase chain reaction analysis. Serum XO levels (means +/- standard deviations) were 207.0 +/- 86.1 IU/mL and 240.6 +/- 114.1 IU/mL in the normal and PEX groups, respectively (p = 0.310). Aqueous XO levels (means +/- standard deviations) were 65.5 +/- 54.3 IU/mL in the normal group and 130.5 +/- 117.4 IU/mL in the PEX group (p = 0.028). There was a 2.9 fold decrease in mRNA expression in anterior lens epithelial cells of PEX, which is significantly lower than the normal group (p = 0.01). Higher aqueous XO levels lacking associated different serum XO suggests higher oxidative stress in the aqueous. Higher aqueous XO levels in PEX with decreased mRNA expression in anterior lens epithelial cells indicate possible overexpression of XO in other structures related to the aqueous.