4-hydroxy-2-nonenal and Glaucoma

To compare the aqueous humor (AH) and serum levels of 4-hydroxynenal (4-HNE) and 8-hydroxy-2'-deoxyguanosine (8-OhdG) in patients with pseudoexfoliation syndrome (PES) and pseudoexfoliation glaucoma (PEG) with each other and with age- and sex-matched control group.. This prospective study included 66 patients divided into three groups: PES (n = 24), PEG (n = 21), and a control group (n = 21). 4-HNE and 8-OhdG levels were analyzed using the enzyme-linked immunosorbent assay.. Aqueous and serum 4-HNE levels were significantly higher in the PEG (466.52 ± 62.12 pg/mL and 313.47 ± 47.41 pg/mL) and PES (290.69 ± 63.63 pg/mL and 201.53 ± 39.57 pg/mL) groups than the control group (144.02 ± 39.58 pg/mL and 99.10 ± 16.96 pg/mL; p < 0.001, for all). Both aqueous and serum levels of 4-HNE in the PEG group were significantly higher than in the PES group (p < 0.001, for both). Similar to 4-HNE, the AH 8-OhdG levels were higher in the PEG group (21.18 ± 2.23 ng/mL) compared to the PES (14.90 ± 3.37 ng/mL) and control (4.86 ± 1.94 ng/mL) groups (p < 0.001, for all). Serum 8-OhdG levels were significantly higher in the PEG and PES groups than the control (p < 0.001, for both); however, there was no significant difference between the PES and PEG groups (p = 0.097). There were strong significant correlations between the aqueous and serum levels of 4-HNE (p < 0.001, r = 0.857) and 8-OhdG (p < 0.001, r = 0.807) among all the patients.. Aqueous humor and serum levels of 4-HNE and 8-OhdG increased in the PES and PEG patients. These findings are potentially significant and add to the growing body of evidence concerning oxidative stress in PES and PEG.

Topics: Aqueous Humor; Deoxyguanosine; Enzyme-Linked Immunosorbent Assay; Exfoliation Syndrome; Glaucoma; Humans; Prospective Studies

To determine whether activity of carbohydrate metabolism enzymes (aldolase, pyruvate kinase, isocitrate dehydrogenase, and malate dehydrogenase) are altered in the glaucomatous trabecular meshwork (TM) compared to controls.. Tissue specimens were obtained from trabeculectomy (n=45 open angle glaucoma; Caucasian, average age 61+/-8 years of age of both genders) and from cadaver eyes (n=15 control and n=5 glaucoma; Caucasian, average age 63+/-4 years of both genders). Protein extracts from TM tissue were prepared in a non-denaturing buffer containing 0.1% genapol. Aldolase activity was measured spectrophotometrically at 240 nm absorbance using reaction of 3-phosphoglycerate with hydrazine to form hydrazone. Pyruvate kinase activity was measured by coupling lactate dehydrogenase with NADPH and pyruvate absorbance was measured at 340 nm. Isocitrate dehydrogenase activity was measured using reduction of NADP to NADPH at the characteristic absorbance at 340 nm. Malate dehydrogenase catalyzes the interconversion of L-malate and oxaloacetate using NADP as a coenzyme, quantified by its absorbance at 340 nm.. Aldolase, pyruvate kinase, isocitrate dehydrogenase, and malate dehyrogenase activities in the glaucomatous TM tissue were found to be reduced 70, 50, 25, and 69 percent, respectively. SDS-PAGE analysis suggests the presence of 4-hydorxynonenal (HNE) modified isocitrate dehydrogenase protein in the glaucomatous TM tissue compared to controls.. Several Krebs cycle enzyme activities are considerably reduced in glaucomatous TM. HNE modified isocitrate dehydrogenase activity is consistent with reduced inactivated form of the protein. Lipid peroxidation product modification of aldolase, pyruvate kinase, and isocitrate dehydrogenase serves as a likely reason for the reduction of enzyme activity.

Topics: Aged; Aldehydes; Blotting, Western; Carbohydrate Metabolism; Down-Regulation; Energy Metabolism; Female; Fructose-Bisphosphate Aldolase; Glaucoma; Humans; Isocitrate Dehydrogenase; Lipid Peroxidation; Male; Middle Aged; Pyruvate Kinase; Trabecular Meshwork

To determine whether oxidative adduct formation or heme oxygenase-1 (HO-1) expression are altered in retinal ganglion cell (RGC) cultures exposed to elevated hydrostatic pressure and in a mouse model of glaucoma.. Cultured RGC-5 cells were subjected to 0, 30, 60, or 100 mm Hg hydrostatic pressure for 2 hours, and the cells were harvested. Parallel experiments examined the recovery from this stress, the effect of direct 4-hydroxy-2-nonenal (HNE) treatment, and the effect of pretreatment with resveratrol or quercetin. Mice were anesthetized and intraocular pressure was increased to 30, 60, or 100 mm Hg for 1 hour; then the retinas were harvested. HNE adduct formation and HO-1 expression were assessed by immunocytochemistry and immunoblotting.. Increases of HNE-protein adducts (up to 5-fold) and HO-1 expression (up to 2.5 fold) in pressure-treated RGC-5 cells were dose dependent. During recovery experiments, HNE-protein adducts continued to increase for up to 10 hours; in contrast, HO-1 expression decreased immediately. HNE, at a concentration as low as 5 muM, led to neurotoxicity in RGC-5 cells. HNE adducts and HO-1 expression increased in the mouse retina and optic nerve after acute IOP elevation up to 5.5-fold and 2-fold, respectively. Antioxidant treatment reduced the oxidative stress level in pressure-treated RGC-5 cells.. This study demonstrates that oxidative stress is an early event in hydrostatic pressure/IOP-induced neuronal damage. These findings support the view that oxidative damage contributes early to glaucomatous optic neuropathy.

Topics: Aldehydes; Animals; Apoptosis; Blotting, Western; Cell Line, Transformed; Cell Survival; Cells, Cultured; Disease Models, Animal; Fluoresceins; Fluorescent Antibody Technique, Indirect; Glaucoma; Heme Oxygenase-1; Hydrostatic Pressure; Intraocular Pressure; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Nuclear Proteins; Optic Nerve Diseases; Oxidative Stress; Rats; Retinal Diseases; Retinal Ganglion Cells