Antioxidant Enzymes in the Aging Human Retinal Pigment Epithelium

Topographic and Age-Dependent Expression of Heme Oxygenase-1 and Catalase in the Human Retinal Pigment Epithelium

“…Our findings on catalase are also not directly comparable to those in the study by Frank et al 4 on protein expression or to the results in the study by Liles et al 6 on total enzyme activity. In normal eyes, Frank et al found a slight decrease in the number of gold particles counted per 50-m 2 area of cytoplasm or lysosome as a function of age.…”

Topographic and Age-Dependent Expression of Heme Oxygenase-1 and Catalase in the Human Retinal Pigment Epithelium

“…Our findings on catalase are also not directly comparable to those in the study by Frank et al 4 on protein expression or to the results in the study by Liles et al 6 on total enzyme activity. In normal eyes, Frank et al found a slight decrease in the number of gold particles counted per 50-m 2 area of cytoplasm or lysosome as a function of age.…”

Similarity of mRNA Phenotypes of Morphologically Normal Macular and Peripheral Retinal Pigment Epithelial Cells in Older Human Eyes

“…The high expression suggests that SOD1 and SOD2, GPX3, GST A4, M1, M4, O1, and peroxiredoxin 1 are relevant isoenzymes in the RPE cell's oxidative defense system. While high catalase expression has been previously reported, 30 our low catalase expression is more consistent with reports of an age-related decline by the RPE. 30,31 The RPE is susceptible to oxidative damage by lipid peroxidation products from phagocytosed outer segments.…”

“…While high catalase expression has been previously reported, 30 our low catalase expression is more consistent with reports of an age-related decline by the RPE. 30,31 The RPE is susceptible to oxidative damage by lipid peroxidation products from phagocytosed outer segments. 32 Lipid peroxidation products are detoxified not by SOD and catalase, but instead by the GST alpha class and GPXs.…”

Antioxidants and Ocular Cell Type Differences in Cytoprotection from Formic Acid Toxicity in Vitro

“…ARPE-19 cells have markedly higher amounts of catalase protein and of catalase activity than 661W cells. Catalase levels have not specifically been compared in extracts of photoreceptor and RPE cells, but the high catalase in the ARPE-19 cell line observed here is consistent with reports indicating that the RPE has the highest levels of catalase activity of several ocular tissues (retina, iris, or vitreous [Liles et al, 1991]). Not only do ARPE-19 cells have higher baseline levels of catalase than 661W cells, but with formic acid exposure, catalase activity decreases in 661W cells and increases in ARPE-19 cells.…”

Topographic and Age-Dependent Expression of Heme Oxygenase-1 and Catalase in the Human Retinal Pigment Epithelium

“…Our findings on catalase are also not directly comparable to those in the study by Frank et al 4 on protein expression or to the results in the study by Liles et al 6 on total enzyme activity. In normal eyes, Frank et al found a slight decrease in the number of gold particles counted per 50-m 2 area of cytoplasm or lysosome as a function of age.…”

Similarity of mRNA Phenotypes of Morphologically Normal Macular and Peripheral Retinal Pigment Epithelial Cells in Older Human Eyes

“…The high expression suggests that SOD1 and SOD2, GPX3, GST A4, M1, M4, O1, and peroxiredoxin 1 are relevant isoenzymes in the RPE cell's oxidative defense system. While high catalase expression has been previously reported, 30 our low catalase expression is more consistent with reports of an age-related decline by the RPE. 30,31 The RPE is susceptible to oxidative damage by lipid peroxidation products from phagocytosed outer segments.…”

“…While high catalase expression has been previously reported, 30 our low catalase expression is more consistent with reports of an age-related decline by the RPE. 30,31 The RPE is susceptible to oxidative damage by lipid peroxidation products from phagocytosed outer segments. 32 Lipid peroxidation products are detoxified not by SOD and catalase, but instead by the GST alpha class and GPXs.…”

Antioxidants and Ocular Cell Type Differences in Cytoprotection from Formic Acid Toxicity in Vitro

“…ARPE-19 cells have markedly higher amounts of catalase protein and of catalase activity than 661W cells. Catalase levels have not specifically been compared in extracts of photoreceptor and RPE cells, but the high catalase in the ARPE-19 cell line observed here is consistent with reports indicating that the RPE has the highest levels of catalase activity of several ocular tissues (retina, iris, or vitreous [Liles et al, 1991]). Not only do ARPE-19 cells have higher baseline levels of catalase than 661W cells, but with formic acid exposure, catalase activity decreases in 661W cells and increases in ARPE-19 cells.…”

Topographic and Age-Dependent Expression of Heme Oxygenase-1 and Catalase in the Human Retinal Pigment Epithelium

“…Our findings on catalase are also not directly comparable to those in the study by Frank et al 4 on protein expression or to the results in the study by Liles et al 6 on total enzyme activity. In normal eyes, Frank et al found a slight decrease in the number of gold particles counted per 50-m 2 area of cytoplasm or lysosome as a function of age.…”

Similarity of mRNA Phenotypes of Morphologically Normal Macular and Peripheral Retinal Pigment Epithelial Cells in Older Human Eyes

“…The high expression suggests that SOD1 and SOD2, GPX3, GST A4, M1, M4, O1, and peroxiredoxin 1 are relevant isoenzymes in the RPE cell's oxidative defense system. While high catalase expression has been previously reported, 30 our low catalase expression is more consistent with reports of an age-related decline by the RPE. 30,31 The RPE is susceptible to oxidative damage by lipid peroxidation products from phagocytosed outer segments.…”

“…While high catalase expression has been previously reported, 30 our low catalase expression is more consistent with reports of an age-related decline by the RPE. 30,31 The RPE is susceptible to oxidative damage by lipid peroxidation products from phagocytosed outer segments. 32 Lipid peroxidation products are detoxified not by SOD and catalase, but instead by the GST alpha class and GPXs.…”

Antioxidants and Ocular Cell Type Differences in Cytoprotection from Formic Acid Toxicity in Vitro

“…ARPE-19 cells have markedly higher amounts of catalase protein and of catalase activity than 661W cells. Catalase levels have not specifically been compared in extracts of photoreceptor and RPE cells, but the high catalase in the ARPE-19 cell line observed here is consistent with reports indicating that the RPE has the highest levels of catalase activity of several ocular tissues (retina, iris, or vitreous [Liles et al, 1991]). Not only do ARPE-19 cells have higher baseline levels of catalase than 661W cells, but with formic acid exposure, catalase activity decreases in 661W cells and increases in ARPE-19 cells.…”