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PubMed1994

Activation of murine macrophages by hydrogen peroxide.

Hydrogen peroxide at concentrations from 0.1 to 20 microM enhances phagocytosis and oxidative burst of murine peritoneal macrophages. The activation of these macrophage functions is paralleled by prolonged hyperpolarization and a transient increase in cytoplasmic free calcium concentration. All the effects are dose- and time-dependent. The results obtained for H2O2 are compared with those for a natural activator, peptide N-formyl-methionyl-leucyl-phenylalanine. The data demonstrate the ability of small doses of hydrogen peroxide to stimulate macrophages through the intracellular mechanisms of ion transduction.

Animals↗

PubMedDate not supplied

Lipid peroxide and hydrogen peroxide formation in parenteral nutrition solutions containing multivitamins.

BACKGROUND: Infusion of parenteral solutions containing peroxides may be detrimental to premature infants. Intralipid frequently contains lipid peroxides and undergoes further peroxidation when exposed to light. Peroxidation is inhibited by ascorbate, and we have proposed that administration of peroxides could be minimized by mixing multivitamins with the Intralipid. In contrast, others have reported that multivitamins generate peroxides and have advised against mixing them with lipid. Our objective was to assess whether light-dependent reactions in parenteral solutions containing MVI Pediatric (MVIP) generate hydrogen peroxide and establish whether addition of multivitamins to Intralipid is beneficial or detrimental. RESULTS: We were unable to make accurate peroxide measurements in MVIP using the ferrous oxidation of xylenol orange (FOX) assay, even though others have used it for this purpose, because of interference by ascorbate. Therefore oxygen release on adding catalase was measured to assay for hydrogen peroxide. Freshly reconstituted solutions contained 250 to 500 micromol/L hydrogen peroxide, and this increased dramatically in ambient light. This is presumably due to light-dependent, riboflavin-catalyzed reduction of oxygen by ascorbic acid. The rate of peroxide generation was less for MVIP diluted in Intralipid than in dextrose solution. CONCLUSIONS: Taken together with our previous findings, we conclude that multivitamins protect Intralipid against lipid peroxidation, but light-dependent hydrogen peroxide production and ascorbate loss occur. These latter changes are less than for multivitamins in other total parenteral nutrition solutions, so there is an advantage in mixing multivitamins with Intralipid. However, prevention of ascorbate loss and hydrogen peroxide formation in any multivitamin solution requires protection of the delivery system from light.

Ascorbic Acid↗

PubMed2003

Effectiveness of treatment with carbamide peroxide and hydrogen peroxide in subjects affected by dental fluorosis: a clinical trial.

Dental fluorosis is an endemic dental health problem around the world; so, it is important to develop clinical alternatives that are non-invasive and inexpensive. In this study, nightguard vital bleaching technique (NVBT), using carbamide and hydrogen peroxide as active agents, has shown itself to be effective in whitening teeth affected by dental fluorosis. Carbamide peroxide at 10 and 20% and hydrogen peroxide at 7.5% showed good clinical effectiveness in improving clinical appearence, but it is important to point out that clinical success is only in cases of class 1 to 3 of the Tooth Surface Index of Fluorosis. When comparing 10 and 20% concentrations of carbamide peroxide, there was no difference in the clinical effectiveness (p > 0.05); but when comparing both concentrations of carbamide peroxide against hydrogen peroxide, results showed that carbamide peroxide was more effective in whitening in cases of dental fluorosis, the difference being statistically significant (p < 0.05). NVBT has two advantages: it is a non-invasive technique and the relationship cost/benefit is excellent; only a few patients reported tenderness or mild tooth sensitivity.

Adolescent↗

PubMed1987

Inhibition of early events in the human T-lymphocyte response to mitogens and alloantigens by hydrogen peroxide.

Hydrogen peroxide (100 to 200 microM) inhibited the response of human peripheral-blood mononuclear cells (PBMCs) in phytohemagglutinin, concanavalin A, and mixed lymphocyte culture assays by more than 90% without affecting cell viability. The response of PBMCs to pokeweed mitogen was stimulated twofold by 50 microM H2O2, but 200 microM H2O2 inhibited the pokeweed mitogen response by more than 95%. A 50 microM concentration of H2O2 completely blocked the generation of cytotoxic T cells in the mixed lymphocyte culture but did not inhibit the production of interleukin 2. Concentrations of 100 microM to 200 microM H2O2 inhibited interleukin 2 production by 45% to 57%. The H2O2 appeared to block early events in T-cell activation, since 200 microM H2O2 was not inhibitory when added one hour after stimulating the cells with phytohemagglutinin. Treatment of PBMCs with 200 microM H2O2 did not decrease the total cellular thiol pool, suggesting that H2O2-mediated inhibition of the proliferative response was not due to thiol oxidation. However, pretreatment of PBMCs with the lipid antioxidants butylated hydroxyanisole, butylated hydroxytoluene, and n-propyl gallate blocked more than 75% of the inhibitory effect of H2O2, suggesting that H2O2 inhibits T-cell activation by inducing lipid peroxidation.

B-Lymphocytes↗

PubMed2005

Antioxidant mechanisms of the Nereidid Laeonereis acuta (Anelida: Polychaeta) to cope with environmental hydrogen peroxide.

Hydrogen peroxide (H(2)O(2)) is a naturally occurring prooxidant molecule, and its effects in the macroinvertebrate infauna were previously observed. The existence of a gradient of antioxidant enzymes activity (catalase [CAT], glutathione peroxidase [GPx], superoxide dismutase [SOD], and glutathione-S-transferase [GST]) and/or oxidative damage along the body of the estuarine polychaeta Laeonereis acuta (Polychaeta, Nereididae) was analyzed after exposure to H(2)O(2). Because this species secretes conspicuous amounts of mucus, its capability in degrading H(2)O(2) was studied. The results suggest that L. acuta deal with the generation of oxidative stress with different strategies along the body. In the posterior region, higher CAT and SOD activities ensure the degradation of inductors of lipid peroxidation such as H(2)O(2) and superoxide anion (O(2)(.-)). The higher GST activity in anterior region aids to conjugate lipid peroxides products. In the middle region, the lack of high CAT, SOD, or GST activities correlates with the higher lipid hydroperoxide levels found after H(2)O(2) exposure. Ten days of exposure to H(2)O(2) also induced oxidative stress (lipid peroxidation and DNA damage) in the whole animal paralleled by a lack of CAT induction. The mucus production contributes substantially to H(2)O(2) degradation, suggesting that bacteria that grow in this secretion provide this capability.

Adaptation, Physiological↗

PubMed1976

Physiology and ultrastructure of the blood platelet following exposure to hydrogen peroxide.

Hydrogen peroxide in micromolar concentrations can induce shape change in human blood platelets, and can modify the aggregation and release reaction of these cells as induced by ADP or thrombin. In larger (millimolar) concentrations, H2O2 produces fusion of platelets with distortions in platelet morphology unlike those normally caused by aggregating agents. The production of H2O2 in vivo by granulocytes or other cells could influence the processes of haemostasis or thrombosis.

Adenosine Diphosphate↗

PubMed1989

[Clinical test of various oral applications of hydrogen peroxide].

Hydrogen peroxide in 3 various kind of applications were used for 3 weeks to treat gingivitis and periodontitis: 3% for mouth rinsing, 3 X daily (treatment at home, not clinical controlled), 3% for pocket washing (clinical controlled) and as Gingivox-strip (10%) 3 X weekly (clinical controlled). The therapeutical success of the 3 tested modifications of application was uniformity, on gingivitis better than on periodontitis. In spite of change for the worse of clinical condition after termination of therapy the first level of inflammation was after 24 weeks yet not reached.

Gingivitis↗

PubMed1993

Activation of the hydroxylase of sMMO from Methylococcus capsulatus (Bath) by hydrogen peroxide.

Hydrogen peroxide can activate the non-heme binuclear iron-containing hydroxylase of soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath) in the catalysis of oxidation of methane and other sMMO substrates. The reductase, protein B, O2 and NADH are normally required for catalytic activity, but can be replaced by H2O2 serving as the source of both oxygen and electrons for the reaction. Similar results have been observed in a different strain of MMO from Methylosinus trichosporium OB3b (Andersson, K.K., Froland, W.A., Lee, S.-K. and Lipscomb, J.D. (1991) New J. Chem. 15, 410-415). The Km,app for H2O2 was found to be 66 mM. Labelled oxygen experiments show that the oxygen atom in the product in the peroxide driven system is derived from H2O2 and not O2. Using C2-C5 alkanes and 2-butene as substrates it was shown that the product distribution differed in the complete sMMO and H2O2-driven systems, indicating that more than one pathway is available to the enzyme. Protein B, which is required for catalytic activity in the complete system, was found to be an inhibitor of the hydroxylase/H2O2 system. It was also observed that protein B not only affected the activity, but also the selectivity of carbon hydroxylation with 2-methylbutane as substrate.

Dose-Response Relationship, Drug↗

PubMed1982

Characterization of sister chromatid exchange induction by hydrogen peroxide.

Hydrogen peroxide (H2O2) induces SCEs in V-79 Chinese hamster cells. The incorporation of BrdUrd sensitizes the cells to the action of H2O2, but damage leading to the formation of SCEs can also be induced in DNA not substitued with BrdUrd. Catalase leads to a complete reduction of the SCE-producing as well as the toxic effect. The amino acid L-cysteine does not reduce the H2O2-induced SCE-frequencies. The results yield information about the relevance of SCE investigations in vitro for the determination of DNA-damaging substances and about the effects of antimutagenic SH-compounds.

Animals↗

PubMed2001

Caspases are reversibly inactivated by hydrogen peroxide.

Hydrogen peroxide (H2O2) is known to both induce and inhibit apoptosis, however the mechanisms are unclear. We found that H2O2 inhibited the activity of recombinant caspase-3 and caspase-8, half-inhibition occurring at about 17 microM H2O2. This inhibition was both prevented and reversed by dithiothreitol while glutathione had little protective effect. 100-200 microM H2O2 added to macrophages after induction of caspase activation by nitric oxide or serum withdrawal substantially inhibited caspase activity. Activation of H2O2-producing NADPH oxidase in macrophages also caused catalase-sensitive inactivation of cellular caspases. The data suggest that the activity of caspases in cells can be directly but reversibly inhibited by H2O2.

Caspase 3↗

PubMed1997

Overexpression of superoxide dismutase and catalase in immortalized neural cells: toxic effects of hydrogen peroxide.

Hydrogen peroxide (H2O2) is a known toxicant which causes its damage via the production of hydroxyl radicals. It has been reported to cause both necrotic and apoptotic cell death. The present study was undertaken to evaluate the mode of H2O2-induced cell death and to assess if overexpression of catalase could protect against its toxicity. H2O2 causes cell death of immortalized CSM 14.1 neural cells in a dose-dependent manner. H2O2-induced death was associated with DNA laddering as shown by agarose gel electrophoresis. Stable overexpression of catalase by transfection of a vector containing human cDNA into these cells markedly attenuated H2O2-induced toxic effects. Transfection of a vector containing a SOD cDNA afforded no protection. These results indicate that H2O2 can lead to the activation of endonuclease enzyme that breaks DNA into oligosomes. These cells which overexpress catalase or SOD will help to determine the specific role of H2O2 or O2- in the deleterious effects of a number of toxins.

Catalase↗

PubMed2006

Expression of human myoglobin in H9c2 cells enhances toxicity to added hydrogen peroxide.

Hydrogen peroxide (H2O2) is implicated in cardiac myocyte (CM) damage during myocardial ischemia-reperfusion (IR) injury. Myoglobin (Mb) is present in CM at significant concentrations and reacts with H2O2 to yield one- and two-electron oxidants that may promote myocardial injury. Paradoxically, hearts from mice lacking Mb are more susceptible to H2O2-induced dysfunction than the corresponding controls [U. Flogel, A. Godecke, L.O. Klotz, J. Schrader, Role of myoglobin in the anti-oxidant defense of the heart, FASEB J. 18 (2004) 1156-1158]. We have overexpressed wild-type or Y103F variant of human Mb in cultured CMs to test whether Mb protects against H2O2 insult. Contrary to expectation, cells expressing WT or the Y103F Mb show increased mitochondrial dysfunction and apoptosis, and decreased ATP in response to H2O2 that follows the order native < Y103F Mb < WT human Mb consistent with the increasing pro-oxidant activity for these proteins. These data indicate that (i) Mb promotes oxidative damage to cultured CM and (ii) Mb may be a useful target for the design of inhibitors of myocardial IR injury.

Amino Acid Sequence↗

PubMed2006

Membrane transport of hydrogen peroxide.

Hydrogen peroxide (H2O2) belongs to the reactive oxygen species (ROS), known as oxidants that can react with various cellular targets thereby causing cell damage or even cell death. On the other hand, recent work has demonstrated that H2O2 also functions as a signalling molecule controlling different essential processes in plants and mammals. Because of these opposing functions the cellular level of H2O2 is likely to be subjected to tight regulation via processes involved in production, distribution and removal. Substantial progress has been made exploring the formation and scavenging of H2O2, whereas little is known about how this signal molecule is transported from its site of origin to the place of action or detoxification. From work in yeast and bacteria it is clear that the diffusion of H2O2 across membranes is limited. We have now obtained direct evidence that selected aquaporin homologues from plants and mammals have the capacity to channel H2O2 across membranes. The main focus of this review is (i) to summarize the most recent evidence for a signalling role of H2O2 in various pathways in plants and mammals and (ii) to discuss the relevance of specific transport of H2O2.

Animals↗

PubMed1989

Cell killing and DNA damage in Chinese hamster V79 cells treated with hydrogen peroxide.

Hydrogen peroxide induces lesions in cells similar to those from ionizing radiation, by a Fenton-type production of hydroxyl radicals. At 4 degrees C significant levels of DAN single-strand breaks (ssb) could be measured using the alkaline elution technique, after a 20-min incubation with 10(-5) mol dm-3 H2O2. Only at higher concentrations of H2O2 (greater than 10(-4) mol dm-3) where the levels of ssb measured corresponded to that induced by more than 18 Gy of X-rays, was any significant cell killing detected in a clonogenic assay. Cell killing was observed to coincide with the measurement of significant levels of DNA double-strand breaks (dsb) using the filter elution technique at pH 9.6. This suggests that dsb and not ssb are important as regards hydroxyl-radical-induced cell kill, as found for ionizing radiation. The correlation of induced dsb with lethal events showed that the predicted lethal effect of the H2O2-induced dsb was approximately 5 times less than that of X-ray-induced dsb. This is compared with data previously obtained which showed differences in the lethality of dsb with the quality of radiation (Prise et al. 1987).

Animals↗

PubMed1993

[Mechanism of constriction and dilatation of pulmonary artery induced by hydrogen peroxide].

Hydrogen peroxide (H2O2) is known to cause transient pulmonary vasoconstriction in isolated lungs perfused with a solution containing no blood components, by inducing vasoactive arachidonate metabolites such as thromboxane A2 (TXA2). However, the exact site of production of the vasoactive arachidonates in the lung tissue is unclear. Using isolated main pulmonary arterial rings obtained from male Sprague-Dawley rats (B.W. 300-350 g), we attempted to examine the arachidonate metabolism, especially that mediated by cyclooxygenase, in the vascular wall of pulmonary artery without endothelium. Changes in isometric tension were used to measure contraction or dilatation of the ring preparation. H2O2 caused transient contraction of the ring, which was treated previously with a solution containing a high concentration of potassium (20 mM). The contractile response was enhanced in parallel with the concentration of H2O2 in the presence or absence of endothelium. Catalase (1000 U/ml), a H2O2 scavenger, completely inhibited the response of the isolated ring (without endothelium) to H2O2. OKY-046 (10(-5) and 10(-4) M), a TXA2 synthetase blocker, partially attenuated the contractile response induced by H2O2. ONO-3708 (10(-5) M), a TXA2 and prostaglandin H2 receptor blocker, fully inhibited the vasoconstriction and caused relaxation of the ring without endothelium after addition of H2O2. Indomethacin (5 microM), a cyclooxygenase inactivator, completely inhibited both vasoconstriction and vasodilation of the denuded ring. H2O2 also induced the release of 6-keto-prostaglandin F1 alpha, a stable metabolite of the vasodilator, prostacyclin, from the pulmonary artery without endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Impairment of phagocytic functions of alveolar macrophages by hydrogen peroxide.

Hydrogen peroxide (H2O2) inhibited phagocytosis and superoxide anion production by rat alveolar macrophages. The inhibition was irreversible and concentration and exposure time dependent. The potential relationship between H2O2-induced biochemical perturbations and impaired alveolar macrophage phagocytic functions was investigated. Alveolar macrophage viability and Fc receptor binding capacity were not affected by H2O2. There was probably no correlation between a H2O2-induced rise in cytosolic [Ca2+] ([Ca2+]i) and the impairment of phagocytosis by alveolar macrophages, as was suggested by the following findings. First, the H2O2-induced rise in [Ca2+]i could be inhibited by chelation of extracellular Ca2+, whereas the H2O2-induced impairment of phagocytosis could not. Second, the H2O2-induced rise in [Ca2+]i was reversible, whereas the impairment of phagocytosis was not. And finally, a rise in [Ca2+]i by incubation of alveolar macrophages with the calcium ionophore A23187 did not affect phagocytosis. Various experiments suggested that ATP depletion may play an important role in the H2O2 toxicity for alveolar macrophages. Comparable concentrations of H2O2 caused an irreversible decrease both in cellular ATP and in phagocytosis and superoxide production by alveolar macrophages. In addition, time course of ATP depletion and induction of impaired alveolar macrophage function were similar. In view of the fact that the strong oxidant H2O2 may react with a large variety of biological substances, possible other toxic lesions may not be excluded as underlying mechanism for H2O2-induced inhibition of phagocytic functions of alveolar macrophages.

Adenosine Diphosphate↗

PubMed2001

Human papilloma virus type 16 E7 genes protect astrocytes against apoptotic and necrotic death induced by hydrogen peroxide.

Hydrogen peroxide is considered to be a dose- and time-dependent mediator in apoptotic and necrotic death. In this study, we examined the signaling of the E6 and E7 proteins with respect to apoptosis or necrosis after H2O2 injury using an in vitro model with overexpressed E6 or E7 genes. For this purpose, the E6 and E7 gene expressing astrocytes were exposed to 10 micromole and 200 micromole H2O2 solutions. Twenty- four hours after treatment with the lower dosage(10 micromole H2O2), control, E6-expressing cells suffered about 45% injury and LXSN-expressing cells decreased by 67% as assessed by LDH release. However, E7-expressing cells showed less injury, resulting in 20-30% of LDH release. Astrocytes expressing E6, E7, LXSN and mock-infected cells showed a typical apoptotic death pattern on the DNA gel after treatment with a low-dose of H2O2 (10 micromole), however they died from necrotic death after a high-dose (200 micromole) H2O2. Overexpression of HPV-E7 genes protected the cells from apoptotic death after a low-dose of H2O2 and from necrotic death after a high-dose of H2O2, while the overexpression of E6 genes from the necrotic death. E7 expressing astrocytes showed higher catalase activity and the levels of E2F protein surged more than 100-folds compared with the control astrocytes. We believe that the activity of E7 protein to protect astrocytes from H2O2 injury was at least partly due to increased catalase, a scavenger protein.

Animals↗

PubMed2002

Tumor-targeted delivery of polyethylene glycol-conjugated D-amino acid oxidase for antitumor therapy via enzymatic generation of hydrogen peroxide.

Hydrogen peroxide (H(2)O(2)) is a strong oxidant that induces apoptosis of tumor cells in vitro. Here, we investigated the antitumor activity of an H(2)O(2)-generating enzyme, D-amino acid oxidase (DAO), and its conjugate with polyethylene glycol (PEG; PEG-DAO). Compared with DAO, PEG-DAO showed improved pharmacokinetic parameters in mice after i.v. injection. PEG-DAO administered i.v. accumulated selectively in tumor tissue with insignificant accumulation in normal organs and tissues. To generate cytotoxic H(2)O(2) at the tumor site, PEG-DAO was first administrated i.v. to tumor-bearing mice. After an adequate lag time, the substrate of DAO, D-proline, was injected i.p. This treatment resulted in significant suppression of tumor growth compared with tumor growth in control animals (not given treatment; P < 0.001). Similar treatment with native DAO showed no effect under the same conditions. Oxidative metabolites were significantly increased in solid tumors by administration of PEG-DAO followed by D-proline (P < 0.002, compared with the group receiving no treatment), as evidenced by thiobarbituric acid-reactive substance assay. This treatment did not affect results from the metabolites in the liver and kidney. These findings suggest that tumor-targeted delivery of DAO is accomplished by using pegylated enzyme and thereby taking advantage of the enhanced permeability and retention effect in solid tumor. PEG-DAO thus delivered together with D-proline produces remarkable antitumor activity via extensive generation of H(2)O(2).

Animals↗