Hydrogen peroxide endothelial cell damage

Ward JF, Blakey WF, Joner El Mammalian Cells are not Killed by DNA Single-strand Breaks Caused by Hydroxyl Radicals from Hydrogen Peroxide Endothelial Cells Against Oxidant Damage. Biochem. Biophys. Res. Commun. 1985 127(1) 270-6. 

Antioxidant effects. Superoxide (02 ) is a free radical which contributes to oxidative stress, a process which causes significant damage to the molecular structure of cells. NO induces the synthesis of endothelial cell superoxide dismutase (ecSOD) the enzyme which forms hydrogen peroxide H2O2 from 02 A positive feedback loop is set up as H202 induces eNOS which produces more NO and so on. This is a protective action as superoxide which is potentially damaging to cells is buffered by NO ... 

Kirkland JB. Lipid peroxidation, protein thiol oxidation and DNA damage in hydrogen peroxide-induced injury to endothelial cells Role of activation of poly(ADP-ribose)polymetasc. Biochim Biophys Acta 1991 1092 319-25. 

DNA damage was assessed in human umbihcal vein endothelial cells exposed to superoxide, hydrogen peroxide, nitric oxide, and peroxynitrite (Ballinger etal. 2000). In both vascular endotheUal and human aortic smooth muscle cells, the mitochondrial DNA was preferentially damaged relative to the transcriptionally inactive nuclear P-globulin gene. Similarly, a dose-dependent decrease in mtDNA-encoded mRNA transcripts was associated with reactive species treatment. Mitochondrial protein synthesis was also inhibited in a dose-dependent manner by peroxynitrite, resulting in decreased cellular ATP levels and mitochondrial redox function. 

The flavonol quercetin has been the subject of much interest in terms of its beneficial properties against oxidative stress [62] and has been shown to exert a potent protective actions against hydrogen peroxide-induced apoptosis of rat thymocytes [63] and cell death in rat hepatocytes (BL-9) [60], as well as reducing oxidative stress and cell damage in fiver tumor cells induced by AAPH (2,2-azobis(2-aminopropane) dihydrochloride) [64]. Quercetin and another flavonol, kaempferol, as well as catechin and the flavone taxifolin, have been observed to suppress the cytotoxicity of 02 and H2O2 to Chinese hamster V79 cells, as assessed by the ability of the flavonoids to prevent the decrease in the number of cell colonies induced by the oxidants [65]. Furthermore, quercetin has been shown to protect cutaneous tissue-associated cells (human skin fibroblasts, keratinocytes, and endothelial cells) from oxidative injury induced by buthionine sulfoximine (BSO), an inhibitor of GSH synthesis [66]. 

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