Decreased plasma cysteinylglycine and taurine levels in branch retinal vein occlusion

Purpose: Our aim was to determine the plasma levels of the
sulfur-containing amino acids homocysteine, cysteine, cysteinylglycine,
glutamylcysteine, glutathione and taurine in
patients with branch retinal vein occlusion (BRVO) and in
healthy subjects and to ascertain whether there are statistically
significant differences between patients and controls.
Methods: Homocysteine, cysteine, cysteinylglycine, glutamylcysteine,
glutathione and taurine plasma levels were
measured in 40 patients with BRVO and 80 age- and gendermatched
control subjects by using laser-induced fluorescence
capillary electrophoresis methods. Wilcoxon’s or Student’s
t test was used, when appropriate, to determine
differences between the groups. Conditional logistic regression
analysis was performed to determine the risk factors for
BRVO. Results: BRVO patients showed significantly lower
plasma concentrations of cysteinylglycine (p = 0.02) and taurine
(p ! 0.0001) than controls. Conversely, there were no
significant differences in plasma homocysteine, cysteine,glutamylcysteine and glutathione between patients with
BRVO and controls. Conditional logistic regression analysis
revealed an odds ratio of 0.95 (95% confidence interval:
0.92–0.98, p = 0.001) for taurine and 0.86 (95% confidence
interval: 0.78–0.96, p = 0.006) for cysteinylglycine. Conclusions:
This study failed to demonstrate an association between
BRVO and the plasma levels of homocysteine, cysteine,
glutamylcysteine and glutathione. Cysteinylglycine and
taurine were significantly lower in BRVO patients, thus suggesting
that reduced plasma levels of these sulfur-containing
amino acids may contribute to the pathogenesis of
BRVO.