Increased malondialdehyde concentration and reduced total antioxidant capacity in aqueous humor and blood samples from patients with glaucoma

PURPOSE: To evaluate the levels of malondialdehyde (MDA) and total antioxidant capacity (TAC) in the blood and aqueous humor of glaucomatous and nonglaucomatous patients. To measure the adenosine triphosphate/adenosine diphosphate/adenosine monophosphate (ATP/ADP/AMP) concentration as a biomarker of the blood energy charge potential. METHODS: We examined 40 consecutive patients with primary open-angle glaucoma scheduled for cataract surgery. Twenty-six age-matched subjects scheduled for cataract surgery were enrolled as a control group. Blood and aqueous humor samples were collected at the time of surgery. MDA concentrations and blood nucleotides were measured with high-performance liquid chromatography. The TAC of the samples was estimated with the oxygen-radical absorbance capacity method. RESULTS: Blood and aqueous humor MDA levels in glaucoma patients (respectively, 0.976±0.370 and 0.145±0.065 μmol/ml) were significantly increased (p<0.001 for both) over those of the control group (respectively, 0.454±0.395 and 0.060±0.039 μmol/ml). In contrast, the control group presented significantly higher TACs than did the glaucoma group in both the blood (control: 2.681±1.101 and glaucoma: 1.617±0.674 μmol Trolox Equi/g; p<0.001) and aqueous humor (control: 0.963±0.302 and glaucoma: 0.788±0.346 μmol Trolox Equi/g; p=0.039). The control group (0.869±0.037) exhibited statistically significant (p<0.001) higher values of blood adenosine triphosphate/adenosine diphosphate (ATP-ADP) levels than did the glaucoma group (0.791±0.037). CONCLUSIONS: Our data further support the hypothesis that oxidative stress and decreased antioxidant defenses are involved in glaucoma. High-performance liquid chromatography appears to be an effective and sensitive method to detect altered levels of oxidative stress markers in glaucoma patients.