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Role of antioxidant enzymes and small molecular weight antioxidants in the pathogenesis of age-related macular degeneration (AMD).

Tokarz P, Kaarniranta K, Blasiak J - Biogerontology (2013)

Bottom Line: The retina is especially prone to oxidative stress due to high oxygen pressure and exposure to UV and blue light promoting ROS generation.Antioxidant enzymes play a major role in ROS scavenging and changes of their expression or/and activity are reported to be associated with AMD.Therefore, the enzymes in the retina along with their genes may constitute a perspective target in AMD prevention and therapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236, Lodz, Poland, ptokarz@biol.uni.lodz.pl.

ABSTRACT
Cells in aerobic condition are constantly exposed to reactive oxygen species (ROS), which may induce damage to biomolecules, including proteins, nucleic acids and lipids. In normal circumstances, the amount of ROS is counterbalanced by cellular antioxidant defence, with its main components-antioxidant enzymes, DNA repair and small molecular weight antioxidants. An imbalance between the production and neutralization of ROS by antioxidant defence is associated with oxidative stress, which plays an important role in the pathogenesis of many age-related and degenerative diseases, including age-related macular degeneration (AMD), affecting the macula-the central part of the retina. The retina is especially prone to oxidative stress due to high oxygen pressure and exposure to UV and blue light promoting ROS generation. Because oxidative stress has an established role in AMD pathogenesis, proper functioning of antioxidant defence may be crucial for the occurrence and progression of this disease. Antioxidant enzymes play a major role in ROS scavenging and changes of their expression or/and activity are reported to be associated with AMD. Therefore, the enzymes in the retina along with their genes may constitute a perspective target in AMD prevention and therapy.

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Related in: MedlinePlus

Schematic presentation of ROS involvement in AMD pathology
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Related In: Results  -  Collection


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Fig1: Schematic presentation of ROS involvement in AMD pathology

Mentions: The retina is a tissue abundant in ROS (Fig. 1). First, the oxygen consumption in the retina is the highest among all human tissues (Yu and Cringle 2001). Second, RPE and photoreceptors are exposed to high-energy light, which is focused in the macula (Youssef et al. 2011). Third, the cell membrane of photoreceptors is rich in polyunsaturated fatty acids (PUFA), which are readily oxidized (Anderson et al. 1974). Fourth, there are many photosensitizers in RPE and photoreceptors (Hunter et al. 2012). Finally, the phagocytosis of POS conducted by RPE cells may be accompanied by a respiratory burst—a rapid eruption of ROS (Miceli et al. 1994). POS which are wearing out contain lipids, proteins and others oxidized particles, the driving force of a respiratory burst, born as a result of exposure to light and oxygen-rich environment in the photoreceptors (Tate et al. 1995).Fig. 1


Role of antioxidant enzymes and small molecular weight antioxidants in the pathogenesis of age-related macular degeneration (AMD).

Tokarz P, Kaarniranta K, Blasiak J - Biogerontology (2013)

Schematic presentation of ROS involvement in AMD pathology
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3824279&req=5

Fig1: Schematic presentation of ROS involvement in AMD pathology
Mentions: The retina is a tissue abundant in ROS (Fig. 1). First, the oxygen consumption in the retina is the highest among all human tissues (Yu and Cringle 2001). Second, RPE and photoreceptors are exposed to high-energy light, which is focused in the macula (Youssef et al. 2011). Third, the cell membrane of photoreceptors is rich in polyunsaturated fatty acids (PUFA), which are readily oxidized (Anderson et al. 1974). Fourth, there are many photosensitizers in RPE and photoreceptors (Hunter et al. 2012). Finally, the phagocytosis of POS conducted by RPE cells may be accompanied by a respiratory burst—a rapid eruption of ROS (Miceli et al. 1994). POS which are wearing out contain lipids, proteins and others oxidized particles, the driving force of a respiratory burst, born as a result of exposure to light and oxygen-rich environment in the photoreceptors (Tate et al. 1995).Fig. 1

Bottom Line: The retina is especially prone to oxidative stress due to high oxygen pressure and exposure to UV and blue light promoting ROS generation.Antioxidant enzymes play a major role in ROS scavenging and changes of their expression or/and activity are reported to be associated with AMD.Therefore, the enzymes in the retina along with their genes may constitute a perspective target in AMD prevention and therapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236, Lodz, Poland, ptokarz@biol.uni.lodz.pl.

ABSTRACT
Cells in aerobic condition are constantly exposed to reactive oxygen species (ROS), which may induce damage to biomolecules, including proteins, nucleic acids and lipids. In normal circumstances, the amount of ROS is counterbalanced by cellular antioxidant defence, with its main components-antioxidant enzymes, DNA repair and small molecular weight antioxidants. An imbalance between the production and neutralization of ROS by antioxidant defence is associated with oxidative stress, which plays an important role in the pathogenesis of many age-related and degenerative diseases, including age-related macular degeneration (AMD), affecting the macula-the central part of the retina. The retina is especially prone to oxidative stress due to high oxygen pressure and exposure to UV and blue light promoting ROS generation. Because oxidative stress has an established role in AMD pathogenesis, proper functioning of antioxidant defence may be crucial for the occurrence and progression of this disease. Antioxidant enzymes play a major role in ROS scavenging and changes of their expression or/and activity are reported to be associated with AMD. Therefore, the enzymes in the retina along with their genes may constitute a perspective target in AMD prevention and therapy.

Show MeSH
Related in: MedlinePlus