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Abdel-Hamid NM, Wahid A, Mohamed EM, Abdel-Aziz MA, Mohafez OM, Bakar S. New pathways driving the experimental hepatoprotective action of tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) against acute hepatotoxicity. Biomed Pharmacother 2016; 79:215-21. [PMID: 27044831 DOI: 10.1016/j.biopha.2016.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 02/27/2016] [Accepted: 02/29/2016] [Indexed: 02/07/2023] Open
Abstract
PURPOSE In absence of liver protective drugs, a large number of hepatopathies may arise during drug administration. This study was executed to investigate the possible new pathways underlying the hepatoprotective effect of Tempol (4-hydroxy-2,2,6,6- tetramethylpiperidine-1-oxyl), following oral administration of carbon tetrachloride in mice. METHODS AND RESULTS Thirty albino mice were randomized into 3 equal groups. The duration of study was 28 days. The groups were classified as follows: Group I (healthy control): received saline, in the same volume of CCl4 dose, daily, orally, for 14 days, then sacrificed. Group II: received CCl4, as a single oral dose only, of 1 ml/kg body weight, dissolved in olive oil (1:1 v/v), the animals of this group were sacrificed 14 days after CCl4 single dose intoxication. Group III (protective Tempol treated): received a single dose of Tempol, 20mg/kg, orally, daily for 14 days. Two hours after the last Tempol dose, animals of group III received a single oral dose of CCl4. Fourteen days later, animals were scarified to collect blood and liver tissues for analysis. Tempol pretreatment significantly captured elevated levels of ALT and AST activities, lipid peroxidation, total bilirubin and increased total thiol and catalase contents. Notably, it significantly reduced the expression of tumor necrosis factor-alpha (TNF-α), Caspase-3 and endoplasmic reticulum (ER) inositol-requiring enzyme 1(IRE1) mRNAs, which is an ER trans membrane sensor that activates the unfolded protein response (UPR) to maintain the ER and cellular function. CONCLUSION Pretreatment with Tempol has potential hepatoprotective effects against acute liver injury, induced by CCl4, through antioxidant and anti-inflammatory activities.
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Affiliation(s)
- N M Abdel-Hamid
- Department of Biochemistry, Faculty of Pharmacy, Kafer Alsheikh University, Egypt.
| | - Ahmed Wahid
- Department of Biochemistry, Faculty of Pharmacy, Minia University, Egypt
| | - E M Mohamed
- Department of Biochemistry, Faculty of Pharmacy, Minia University, Egypt
| | - M A Abdel-Aziz
- Department of Biochemistry, Faculty of Pharmacy, Al-Azhar University, Assiut Branch, Egypt
| | - O M Mohafez
- Department of Biochemistry, Faculty of Pharmacy, Al-Azhar University, Assiut Branch, Egypt
| | - Sally Bakar
- Department of Biochemistry, Faculty of Medicine, Assiut University, Egypt
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Amaral JH, Montenegro MF, Pinheiro LC, Ferreira GC, Barroso RP, Costa-Filho AJ, Tanus-Santos JE. TEMPOL enhances the antihypertensive effects of sodium nitrite by mechanisms facilitating nitrite-derived gastric nitric oxide formation. Free Radic Biol Med 2013; 65:446-455. [PMID: 23892053 DOI: 10.1016/j.freeradbiomed.2013.07.032] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 07/04/2013] [Accepted: 07/18/2013] [Indexed: 12/31/2022]
Abstract
Orally administered nitrite exerts antihypertensive effects associated with increased gastric nitric oxide (NO) formation. While reducing agents facilitate NO formation from nitrite, no previous study has examined whether antioxidants with reducing properties improve the antihypertensive responses to orally administered nitrite. We hypothesized that TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl) could enhance the hypotensive effects of nitrite in hypertensive rats by exerting antioxidant effects (and enhancing NO bioavailability) and by promoting gastric nitrite-derived NO generation. The hypotensive effects of intravenous and oral sodium nitrite were assessed in unanesthetized freely moving rats with L-NAME (N(ω)-nitro-L-arginine methyl ester; 100mg/kg; po)-induced hypertension treated with TEMPOL (18mg/kg; po) or vehicle. While TEMPOL exerted antioxidant effects in hypertensive rats, as revealed by lower plasma 8-isoprostane and vascular reactive oxygen species levels, this antioxidant did not affect the hypotensive responses to intravenous nitrite. Conversely, TEMPOL enhanced the dose-dependent hypotensive responses to orally administered nitrite, and this effect was associated with higher increases in plasma nitrite and lower increases in plasma nitrate concentrations. In vitro experiments using electrochemical and chemiluminescence NO detection under variable pH conditions showed that TEMPOL enhanced nitrite-derived NO formation, especially at low pH (2.0 to 4.0). TEMPOL signal evaluated by electron paramagnetic resonance decreased when nitrite was reduced to NO under acidic conditions. Consistent with these findings, increasing gastric pH with omeprazole (30mg/kg; po) attenuated the hypotensive responses to nitrite and blunted the enhancement in plasma nitrite concentrations and hypotensive effects induced by TEMPOL. Nitrite-derived NO formation in vivo was confirmed by using the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (C-PTIO), which blunted the responses to oral nitrite. Our results showed that TEMPOL promotes nitrite reduction to NO in the stomach and enhanced plasma nitrite concentrations and the hypotensive effects of oral sodium nitrite through mechanisms critically dependent on gastric pH. Interestingly, the effects of TEMPOL on nitrite-mediated hypotension cannot be explained by increased NO formation in the stomach alone, but rather appear more directly related to increased plasma nitrite levels and reduced nitrate levels during TEMPOL treatment. This may relate to enhanced nitrite uptake or reduced nitrate formation from NO or nitrite.
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Affiliation(s)
- Jefferson H Amaral
- Department of Pharmacology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Marcelo F Montenegro
- Department of Pharmacology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Lucas C Pinheiro
- Department of Pharmacology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Graziele C Ferreira
- Department of Pharmacology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Rafael P Barroso
- Department of Physics, Faculty of Philosophy, Sciences and Letters of Ribeirao Preto. Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto, SP, Brazil
| | - Antonio J Costa-Filho
- Department of Physics, Faculty of Philosophy, Sciences and Letters of Ribeirao Preto. Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto, SP, Brazil
| | - Jose E Tanus-Santos
- Department of Pharmacology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil.
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Mikkelsen L, Sheykhzade M, Jensen KA, Saber AT, Jacobsen NR, Vogel U, Wallin H, Loft S, Møller P. Modest effect on plaque progression and vasodilatory function in atherosclerosis-prone mice exposed to nanosized TiO(2). Part Fibre Toxicol 2011; 8:32. [PMID: 22074227 PMCID: PMC3245428 DOI: 10.1186/1743-8977-8-32] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 11/10/2011] [Indexed: 02/07/2023] Open
Abstract
Background There is growing evidence that exposure to small size particulate matter increases the risk of developing cardiovascular disease. Methods We investigated plaque progression and vasodilatory function in apolipoprotein E knockout (ApoE-/-) mice exposed to TiO2. ApoE-/- mice were intratracheally instilled (0.5 mg/kg bodyweight) with rutile fine TiO2 (fTiO2, 288 nm), photocatalytic 92/8 anatase/rutile TiO2 (pTiO2, 12 nm), or rutile nano TiO2 (nTiO2, 21.6 nm) at 26 and 2 hours before measurement of vasodilatory function in aorta segments mounted in myographs. The progression of atherosclerotic plaques in aorta was assessed in mice exposed to nanosized TiO2 (0.5 mg/kg bodyweight) once a week for 4 weeks. We measured mRNA levels of Mcp-1, Mip-2, Vcam-1, Icam-1 and Vegf in lung tissue to assess pulmonary inflammation and vascular function. TiO2-induced alterations in nitric oxide (NO) production were assessed in human umbilical vein endothelial cells (HUVECs). Results The exposure to nTiO2 was associated with a modest increase in plaque progression in aorta, whereas there were unaltered vasodilatory function and expression levels of Mcp-1, Mip-2, Vcam-1, Icam-1 and Vegf in lung tissue. The ApoE-/- mice exposed to fine and photocatalytic TiO2 had unaltered vasodilatory function and lung tissue inflammatory gene expression. The unaltered NO-dependent vasodilatory function was supported by observations in HUVECs where the NO production was only increased by exposure to nTiO2. Conclusion Repeated exposure to nanosized TiO2 particles was associated with modest plaque progression in ApoE-/- mice. There were no associations between the pulmonary TiO2 exposure and inflammation or vasodilatory dysfunction.
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Affiliation(s)
- Lone Mikkelsen
- Department of Public Health, University of Copenhagen, 1014 Copenhagen K, Denmark
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4
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Reeder BJ. The redox activity of hemoglobins: from physiologic functions to pathologic mechanisms. Antioxid Redox Signal 2010; 13:1087-123. [PMID: 20170402 DOI: 10.1089/ars.2009.2974] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Pentacoordinate respiratory hemoproteins such as hemoglobin and myoglobin have evolved to supply cells with oxygen. However, these respiratory heme proteins are also known to function as redox enzymes, reacting with compounds such as nitric oxide and peroxides. The recent discoveries of hexacoordinate hemoglobins in vertebrates and nonsymbiotic plants suggest that the redox activity of globins is inherent to the molecule. The uncontrolled formation of radical species resulting from such redox chemistry on respiratory hemoproteins can lead to oxidative damage and cellular toxicity. In this review, we examine the functions of various globins and the mechanisms by which these globins act as redox enzymes under physiologic conditions. Evidence that redox reactions also occur under disease conditions, leading to pathologic complications, also is examined, focusing on recent discoveries showing that the ferryl oxidation state of these hemoproteins is present in these disease states in vivo. In addition, we review the latest advances in the understanding of globin redox mechanisms and how they might affect cellular signaling pathways and how they might be controlled therapeutically or, in the case of hemoglobin-based blood substitutes, through rational design.
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Affiliation(s)
- Brandon J Reeder
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, England.
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Oxidative stress increases blood-brain barrier permeability and induces alterations in occludin during hypoxia-reoxygenation. J Cereb Blood Flow Metab 2010; 30:1625-36. [PMID: 20234382 PMCID: PMC2949263 DOI: 10.1038/jcbfm.2010.29] [Citation(s) in RCA: 243] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The blood-brain barrier (BBB) has a critical role in central nervous system homeostasis. Intercellular tight junction (TJ) protein complexes of the brain microvasculature limit paracellular diffusion of substances from the blood into the brain. Hypoxia and reoxygenation (HR) is a central component to numerous disease states and pathologic conditions. We have previously shown that HR can influence the permeability of the BBB as well as the critical TJ protein occludin. During HR, free radicals are produced, which may lead to oxidative stress. Using the free radical scavenger tempol (200 mg/kg, intraperitoneal), we show that oxidative stress produced during HR (6% O(2) for 1 h, followed by room air for 20 min) mediates an increase in BBB permeability in vivo using in situ brain perfusion. We also show that these changes are associated with alterations in the structure and localization of occludin. Our data indicate that oxidative stress is associated with movement of occludin away from the TJ. Furthermore, subcellular fractionation of cerebral microvessels reveals alterations in occludin oligomeric assemblies in TJ associated with plasma membrane lipid rafts. Our data suggest that pharmacological inhibition of disease states with an HR component may help preserve BBB functional integrity.
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Zhao H, Meng X, Yuan H, Lan M. Novel melphalan and chlorambucil derivatives of 2,2,6,6-tetramethyl-1-piperidinyloxy radicals: synthesis, characterization, and biological evaluation in vitro. Chem Pharm Bull (Tokyo) 2010; 58:332-5. [PMID: 20190437 DOI: 10.1248/cpb.58.332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A series of spin-labeled melphalan and chlorambucil derivatives, coupling the alkylating agents with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radicals, were synthesized, characterized, and their biological properties in vitro were evaluated. These compounds showed much higher cytotoxic activity against human leukemia cell line K562 in vitro than their parent compounds.
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Affiliation(s)
- Hongli Zhao
- Key Laboratory for Advanced Materials, and Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237, P. R.China
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7
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Kang LS, Reyes RA, Muller-Delp JM. Aging impairs flow-induced dilation in coronary arterioles: role of NO and H(2)O(2). Am J Physiol Heart Circ Physiol 2009; 297:H1087-95. [PMID: 19617414 DOI: 10.1152/ajpheart.00356.2009] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aging contributes significantly to the development of cardiovascular disease and is associated with elevated production of reactive oxygen species (ROS). The beneficial effects of nitric oxide (NO)-mediated vasodilation are quickly abolished in the presence of ROS, and this effect may be augmented with aging. We previously demonstrated an age-induced impairment of flow-induced dilation in rat coronary arterioles. Therefore, the purpose of this study was to determine the effects of O(2)(-) scavenging, as well as removal of H(2)O(2), the byproduct of O(2)(-) scavenging, on flow-mediated dilation in coronary resistance arterioles of young (4 mo) and old (24 mo) male Fischer 344 rats. Flow increased NO and H(2)O(2) production as evidenced by enhanced diaminofluorescein and dichlorodihydrofluorescein fluorescence, respectively, whereas aging reduced flow-induced NO and H(2)O(2) production. Endothelium-dependent vasodilation was evaluated by increasing intraluminal flow (5-60 nl/s) before and after treatment with the superoxide dismutase mimetic Tempol (100 muM), the H(2)O(2) scavenger catalase (100 U/ml), or Tempol plus catalase. Catalase reduced flow-induced dilation in both groups, whereas Tempol and Tempol plus catalase diminished vasodilation in young but not old rats. Tempol plus deferoxamine (100 muM), an inhibitor of hydroxyl radical formation, reversed Tempol-mediated impairment of flow-induced vasodilation in young rats and improved flow-induced vasodilation in old rats compared with control. Immunoblot analysis revealed increases in endogenous superoxide dismutase, catalase, and nitrotyrosine protein levels with aging. Collectively, these data indicate that NO- and H(2)O(2)-mediated flow-induced signaling decline with age in coronary arterioles and that elevated hydroxyl radical formation contributes to the age-related impairment of flow-induced vasodilation.
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Affiliation(s)
- Lori S Kang
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
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8
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Simonsen U, Christensen FH, Buus NH. The effect of tempol on endothelium-dependent vasodilatation and blood pressure. Pharmacol Ther 2009; 122:109-24. [DOI: 10.1016/j.pharmthera.2009.02.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 02/05/2009] [Indexed: 02/07/2023]
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Wilcox CS, Pearlman A. Chemistry and antihypertensive effects of tempol and other nitroxides. Pharmacol Rev 2009; 60:418-69. [PMID: 19112152 DOI: 10.1124/pr.108.000240] [Citation(s) in RCA: 290] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nitroxides can undergo one- or two-electron reduction reactions to hydroxylamines or oxammonium cations, respectively, which themselves are interconvertible, thereby providing redox metabolic actions. 4-Hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (tempol) is the most extensively studied nitroxide. It is a cell membrane-permeable amphilite that dismutates superoxide catalytically, facilitates hydrogen peroxide metabolism by catalase-like actions, and limits formation of toxic hydroxyl radicals produced by Fenton reactions. It is broadly effective in detoxifying these reactive oxygen species in cell and animal studies. When administered intravenously to hypertensive rodent models, tempol caused rapid and reversible dose-dependent reductions in blood pressure in 22 of 26 studies. This was accompanied by vasodilation, increased nitric oxide activity, reduced sympathetic nervous system activity at central and peripheral sites, and enhanced potassium channel conductance in blood vessels and neurons. When administered orally or by infusion over days or weeks to hypertensive rodent models, it reduced blood pressure in 59 of 68 studies. This was accompanied by correction of salt sensitivity and endothelial dysfunction and reduced agonist-evoked oxidative stress and contractility of blood vessels, reduced renal vascular resistance, and increased renal tissue oxygen tension. Thus, tempol is broadly effective in reducing blood pressure, whether given by acute intravenous injection or by prolonged administration, in a wide range of rodent models of hypertension.
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Affiliation(s)
- Christopher S Wilcox
- Division of Nephrology and Hypertension, Kidney and Vascular Disorder Center, Georgetown University, Washington, DC 20007, USA.
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10
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Effects of Tempol, a Membrane-Permeable Radical Scavenger, on Local and Remote Organ Injuries Caused by Intestinal Ischemia/Reperfusion in Rats. J Surg Res 2008; 149:259-71. [DOI: 10.1016/j.jss.2007.12.791] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 11/12/2007] [Accepted: 12/19/2007] [Indexed: 11/22/2022]
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Abstract
Interstitial lung disease encompasses a large group of chronic lung disorders associated with excessive tissue remodeling, scarring, and fibrosis. The evidence of a redox imbalance in lung fibrosis is substantial, and the rationale for testing antioxidants as potential new therapeutics for lung fibrosis is appealing. Current animal models of lung fibrosis have clear involvement of ROS in their pathogenesis. New classes of antioxidant agents divided into catalytic antioxidant mimetics and antioxidant scavengers are being developed. The catalytic antioxidant class is based on endogenous antioxidant enzymes and includes the manganese-containing macrocyclics, porphyrins, salens, and the non-metal-containing nitroxides. The antioxidant scavenging class is based on endogenous antioxidant molecules and includes the vitamin E analogues, thiols, lazaroids, and polyphenolic agents. Numerous studies have shown oxidative stress to be associated with many interstitial lung diseases and that these agents are effective in attenuating fibroproliferative responses in the lung of animals and humans.
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Affiliation(s)
- Brian J Day
- Division of Environmental and Occupational Health Sciences, Department of Medicine, National Jewish Medical and Research Center, Denver, Colorado 80206, USA.
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12
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Soule BP, Hyodo F, Matsumoto KI, Simone NL, Cook JA, Krishna MC, Mitchell JB. Therapeutic and clinical applications of nitroxide compounds. Antioxid Redox Signal 2007; 9:1731-43. [PMID: 17665971 DOI: 10.1089/ars.2007.1722] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Nitroxide compounds have been used for many years as biophysical tools, but only during the past 15-20 years have the many interesting biochemical interactions been discovered and harnessed for therapeutic applications. By modifying oxidative stress and altering the redox status of tissues, nitroxides have the ability to interact with and alter many metabolic processes. This interaction can be exploited for therapeutic and research use, including protection against ionizing radiation, as probes in functional magnetic resonance imaging, cancer prevention and treatment, control of hypertension and weight, and protection from damage resulting from ischemia/reperfusion injury. Although much remains to be done, many applications have been well studied, and some are presently being tested in clinical trials. The therapeutic and research uses of nitroxides are reviewed here, with a focus on the progress from initial development to modern, state-of-the art trials.
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Affiliation(s)
- Benjamin P Soule
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA.
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Soule BP, Hyodo F, Matsumoto KI, Simone NL, Cook JA, Krishna MC, Mitchell JB. The chemistry and biology of nitroxide compounds. Free Radic Biol Med 2007; 42:1632-50. [PMID: 17462532 PMCID: PMC1991293 DOI: 10.1016/j.freeradbiomed.2007.02.030] [Citation(s) in RCA: 387] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Revised: 02/21/2007] [Accepted: 02/27/2007] [Indexed: 02/04/2023]
Abstract
Cyclic nitroxides are a diverse group range of stable free radicals that have unique antioxidant properties. Because of their ability to interact with free radicals, they have been used for many years as biophysical tools. During the past 15-20 years, however, many interesting biochemical interactions have been discovered and harnessed for therapeutic applications. Biologically relevant effects of nitroxides have been described, including their ability to degrade superoxide and peroxide, inhibit Fenton reactions, and undergo radical-radical recombination. Cellular studies defined the activity of nitroxides in vitro. By modifying oxidative stress and altering the redox status of tissues, nitroxides have been found to interact with and alter many metabolic processes. These interactions can be exploited for therapeutic and research use, including protection against ionizing radiation, as probes in functional magnetic resonance imaging, cancer prevention and treatment, control of hypertension and weight, and protection from damage resulting from ischemia/reperfusion injury. Although much remains to be done, many applications have been well studied and some are currently being tested in clinical trials. The therapeutic and research uses of nitroxide compounds are reviewed here with a focus on the progress from initial development to modern trials.
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Affiliation(s)
- Benjamin P Soule
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
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14
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Garcia SC, Pomblum V, Gams E, Langenbach MR, Schipke JD. Independency of myocardial stunning of endothelial stunning? Basic Res Cardiol 2007; 102:359-67. [PMID: 17520313 DOI: 10.1007/s00395-007-0657-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 04/05/2007] [Accepted: 04/24/2007] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND OBJECTIVE Vascular endothelial cells play an important role in the control of vascular tone. The reasons for coronary endothelial dysfunction are complex and may involve ischemia/reperfusion injury. We investigated whether endothelial, smooth muscle, and myocardial dysfunction are independent phenomena. METHODS Rabbit hearts were rapidly excised without intermittent ischemia, connected to a modified Langendorff apparatus, and perfused with a modified Krebs-Henseleit solution containing bovine erythrocytes. Normoxic control hearts (n = 16) were perfused for 125 min. Postischemic hearts (n = 15) were perfused for 45 min, submitted to global ischemia (20 min) and reperfused (60 min). Both the normoxic and the postischemic hearts were divided into three groups that received either 0.9% NaCl (placebo), or 3-morpholinosydnonimine (SIN-1; 100 microM),or substance P (SP; 5 nM). RESULTS After SIN-1, CBF in the normoxic hearts was increased by maximum 63% and after SP by 62%. 60 min after the onset of reperfusion, the postischemic hearts of both groups had recovered to 95% LVP(max). In the postischemic hearts, SIN-1 increased CBF still by 58%, while the endothelium-dependent vasomotion was impaired: SP improved CBF by only 9%. SUMMARY AND CONCLUSIONS The particular protocol permitted differentiation between myocardial and vascular stunning. The results show that, while myocardial function has already recovered, endothelial cells are more severely impaired than smooth muscle cells, and that this injury persists beyond myocardial stunning. Thus, endothelial-dependent dysfunction can still impair vasodilatation while ventricular dysfunction has already resolved.
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Affiliation(s)
- Solange C Garcia
- Research Group Experimental Surgery, Dept. of Thoracic- and Cardiovascular Surgery, University Hospital Duesseldorf, Düsseldorf, Germany
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15
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Didion SP, Kinzenbaw DA, Schrader LI, Faraci FM. Heterozygous CuZn superoxide dismutase deficiency produces a vascular phenotype with aging. Hypertension 2006; 48:1072-9. [PMID: 17043164 DOI: 10.1161/01.hyp.0000247302.20559.3a] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The goal of this study was to test the hypothesis that loss of a single copy of the gene for CuZn superoxide dismutase (CuZnSOD) increases vascular superoxide levels and produces vascular dysfunction with aging. Responses of carotid arteries from young (7 months) and old (22 to 24 months of age) heterozygous CuZnSOD-deficient (CuZnSOD(+/-)) mice and their wild-type (CuZnSOD(+/+)) littermates were examined in vitro. Total superoxide dismutase activity in aorta was reduced by approximately 30% (P<0.05) in CuZnSOD(+/-) mice compared with wild-type mice. Responses to acetylcholine (an endothelium-dependent agonist) produced relaxation that was similar (P>0.05) in carotid arteries from young wild-type, young CuZnSOD(+/-), and old wild-type mice. In contrast, relaxation to acetylcholine was markedly impaired in old CuZnSOD(+/-) mice (eg, 100 micromol/L acetylcholine produced 51+/-5% and 96+/-5% relaxation in vessels from old CuZnSOD(+/-) and old wild-type mice, respectively). This effect was selective, because relaxation to nitroprusside (an endothelium-independent agonist) was not affected by either CuZnSOD genotype or aging. The impaired response to acetylcholine in old CuZnSOD(+/-) mice was restored toward normal with either tempol (a scavenger of superoxide; 1 mmol/L) or PJ34 (an inhibitor of poly-ADP-ribose polymerase; 3 micromol/L). Vascular superoxide levels were increased in aorta in old CuZnSOD(+/+) mice and increased further in CuZnSOD(+/-) mice with aging. These findings provide the first direct evidence that normal CuZnSOD expression protects endothelial function and that deficiency in a single copy of the gene that encodes CuZnSOD produces increases in superoxide and marked impairment of endothelial function with aging.
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Affiliation(s)
- Sean P Didion
- Department of Internal Medicine, Cardiovascular Center, University of Iowa Carver College of Medicine, Iowa City 52242, USA.
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Ruaño G, Thompson PD, Windemuth A, Smith A, Kocherla M, Holford TR, Seip R, Wu AH. Physiogenomic analysis links serum creatine kinase activities during statin therapy to vascular smooth muscle homeostasis. Pharmacogenomics 2005; 6:865-72. [PMID: 16296949 DOI: 10.2217/14622416.6.8.865] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Statins are highly effective at reducing coronary disease risk. The main side effects of these medications are a variety of skeletal muscle complaints ranging from mild myalgia to frank rhabdomyolysis. To search for physiologic factors possibly influencing statin muscle toxicity, we screened for genetic associations with serum creatine kinase (CK) levels in 102 patients receiving statin therapy for hypercholesteremia. A total of 19 single nucleotide polymorphism (SNPs) were selected from ten candidate genes involved in vascular homeostasis. Multiple linear regression was used to rank the SNPs according to probability of association, and the most significant associations were analyzed in greater detail. SNPs in the angiotensin II Type 1 receptor (AGTR1) and nitric oxide synthase 3 (NOS3) genes were significantly associated with CK activity. These results demonstrate a strong association between CK activity during statin treatment and variability in genes related to vascular function, and suggest that vascular smooth muscle function may contribute to the muscle side effects of statins.
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Liaw WJ, Chen TH, Lai ZZ, Chen SJ, Chen A, Tzao C, Wu JY, Wu CC. EFFECTS OF A MEMBRANE-PERMEABLE RADICAL SCAVENGER, TEMPOL, ON INTRAPERITONEAL SEPSIS-INDUCED ORGAN INJURY IN RATS. Shock 2005; 23:88-96. [PMID: 15614137 DOI: 10.1097/01.shk.0000145937.70085.89] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
There is good evidence that endotoxemia, sepsis, and septic shock are associated with the generation and release of reactive oxygen species (ROS) such as superoxide anion (O2), indicating that oxygen-derived free radicals play an important role in the pathogenesis of sepsis/shock. Studies on the application of free oxygen radical scavengers to limit the damage to tissues and organs have been recently attempted. A stable piperidine nitroxide of low molecular weight (Tempol) can permeate biological membranes and scavenge O2 in vitro and in vivo. Thus, we investigated effects of Tempol on the circulatory failure and multiple organ injuries caused by a clinically relevant polymicrobial sepsis model in the rat-cecal ligation and puncture (CLP). CLP not only successfully induced circulatory failure but also substantially increased plasma concentrations of glutamate-oxalate-transferase and glutamate-pyruvate-transferase (indicators of liver injury), creatinine and blood urea nitrogen (indicators of kidney injury), and decreased base excess in arterial blood in the late stage, indicating the development of multiple organ injury in this study. These were also confirmed by a histologic examination showing that the CLP-induced sepsis accompanied increase of polymorphonuclear neutrophil (PMN) infiltration in the lung and sequestration in the liver. Our results demonstrated that Tempol not only ameliorated the deterioration of hemodynamic changes and renal and liver injuries but also attenuated PMN infiltration in the lung and sequestration in the liver (histology). In addition, Tempol improved the survival in CLP-induced septic rats. Moreover, Tempol reduced the plasma NO. and interleukin-1beta and organ O2 levels in CLP-treated rats. In conclusion, Tempol prevented circulatory failure and attenuated organ dysfunction/injury as well as decreased the mortality rate in CLP-treated animals. These beneficial effects of Tempol may be attributed to inhibition of ROS formation (e.g., NO. and O2), suggesting antioxidant (e.g., Tempol) is a potential therapeutic agent in the treatment of intraperitoneal septic shock.
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Affiliation(s)
- Wen-Jinn Liaw
- Department of Anesthesiology, Tri-Service General Hospital, Taipei, Taiwan.
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18
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Nithipatikom K, Holmes BB, McCoy MJ, Hillard CJ, Campbell WB. Chronic administration of nitric oxide reduces angiotensin II receptor type 1 expression and aldosterone synthesis in zona glomerulosa cells. Am J Physiol Endocrinol Metab 2004; 287:E820-7. [PMID: 15198935 DOI: 10.1152/ajpendo.00183.2004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acute nitric oxide (NO) inhibits angiotensin II (ANG II)-stimulated aldosterone synthesis in zona glomerulosa (ZG) cells. In this study, we investigated the effects of chronic administration of NO on the ANG II receptor type 1 (AT1) expression and aldosterone synthesis. ZG cells were treated daily with DETA NONOate (10(-4) M), an NO donor, for 0, 12, 24, 48, 72, and 96 h. Chinese hamster ovary (CHO) cells, stably transfected with the AT1B receptor, were used as a positive control. Western blot analysis indicated that AT1 receptor expression was decreased as a function of time of NO administration in both CHO and ZG cells. ANG II binding to its receptors was determined by radioligand binding. NO treatment of ZG cells for 96 h resulted in a decrease in ANG II binding compared with control. The receptor density was decreased to 1,864 +/- 129 fmol/mg protein from 3,157 +/- 220 fmol/mg protein (P < 0.005), but the affinity was not changed (1.95 +/- 0.22 vs. 1.88 +/- 0.21 nM). Confocal Raman microspectroscopy and immunocytochemistry both confirmed that the expression of AT1 receptors in ZG cells decreased with chronic NO administration. In addition, chronic NO administration also decreased the expression of cholesterol side-chain cleavage enzyme in ZG cells and inhibited ANG II- and 25-hydroxycholesterol-stimulated aldosterone synthesis in ZG cells. This study demonstrates that chronic administration of NO inhibits aldosterone synthesis in ZG cells by downregulation of the expression of both AT1 receptors and cholesterol side-chain cleavage enzyme.
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Affiliation(s)
- Kasem Nithipatikom
- Dept. of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA
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19
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Alpert E, Altman H, Totary H, Gruzman A, Barnea D, Barash V, Sasson S. 4-Hydroxy tempol-induced impairment of mitochondrial function and augmentation of glucose transport in vascular endothelial and smooth muscle cells. Biochem Pharmacol 2004; 67:1985-95. [PMID: 15130774 DOI: 10.1016/j.bcp.2004.02.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2003] [Accepted: 02/02/2004] [Indexed: 11/21/2022]
Abstract
The water-soluble and cell permeable nitroxide derivative 4-hydroxy tempol (TPL) has been shown to reduce or ameliorate oxidative stress-induced dysfunction and damage in vascular endothelial cells. We studied the effects of TPL on glucose transport and metabolism in bovine aortic endothelial (VEC) and smooth muscle cells (VSMC) under normal and high glucose conditions. Normally, these cells operate an autoregulatory protective mechanism that limits the rate of glucose transport under hyperglycemic conditions by decreasing the cell content of their typical glucose transporter GLUT-1 mRNA and protein as well as its plasma membrane abundance. TPL augmented the rate of glucose transport both under normo- and hyperglycemic conditions by increasing GLUT-1 mRNA and protein content and its plasma membrane abundance in both types of cells, leading to an increased flux of glucose into the cells. These effects were found related to ROS-generating and oxidant activities of TPL and to a decreased rate of mitochondrial ATP production under both normo- and hyperglycemic conditions. Since impaired mitochondrial functions, and in particular decreased rate of ATP production, augment the expression of GLUT-1 protein and glucose transport and metabolism, we suggest that the stimulatory effects of TPL in vascular cells results from its unfavorable interactions in the mitochondrion. It is therefore suggested that effects of TPL in cells of cardiovascular system be evaluated in parallel to its adverse effects on glucose and energy metabolism.
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Affiliation(s)
- Evgenia Alpert
- Department of Pharmacology, School of Pharmacy, The Hebrew University-Hadassah Faculty of Medicine, P.O. Box 12272, Jerusalem 91120, Israel
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20
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Thiemermann C. Membrane-permeable radical scavengers (tempol) for shock, ischemia-reperfusion injury, and inflammation. Crit Care Med 2003; 31:S76-84. [PMID: 12544980 DOI: 10.1097/00003246-200301001-00011] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Christoph Thiemermann
- Department of Experimental Medicine and Nephrology, William Harvey Research Institute, St. Bartholomew's Hospital Medical College, London EC1M6BQ, UK.
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21
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Patel NSA, Chatterjee PK, Chatterjee BE, Cuzzocrea S, Serraino I, Brown PAJ, Stewart KN, Mota-Filipe H, Thiemermann C. TEMPONE reduces renal dysfunction and injury mediated by oxidative stress of the rat kidney. Free Radic Biol Med 2002; 33:1575-89. [PMID: 12446215 DOI: 10.1016/s0891-5849(02)01116-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Here we investigate the effects of the stable, water-soluble nitroxyl radical, TEMPONE, on renal dysfunction and injury caused by ischemia/reperfusion (I/R) of the rat kidney in vivo. TEMPONE significantly improved both glomerular and tubular function (serum urea, creatinine, creatinine clearance, and fractional excretion of Na(+)) in a dose-dependent manner and significantly attenuated the reperfusion-injury associated with I/R (urinary N-acetyl-beta-D-glucosaminidase, aspartate aminotransferase, assessment of renal histology). TEMPONE also markedly reduced the immunohistochemical evidence of the formation of nitrotyrosine and poly(ADP-ribose), indicating reduction of nitrosative and oxidative stress, respectively. The latter was reflected in vitro, where TEMPONE significantly reduced cellular injury of primary cultures of rat renal proximal tubular (PT) cells caused by hydrogen peroxide in a dose-dependent manner. Importantly, in contrast to its in vivo metabolite TEMPOL (which also provided protective effects against renal I/R and oxidative stress of PT cells), TEMPONE reduced renal dysfunction and injury without causing a significant reduction in blood pressure upon administration. These results suggest, for the first time, that TEMPONE can reduce the renal dysfunction and injury caused by I/R and the injury caused to PT cells by oxidative stress without producing the adverse cardiovascular effects observed when using other nitroxyl radicals.
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Affiliation(s)
- Nimesh S A Patel
- Department of Experimental Medicine and Nephrology, The William Harvey Research Institute, London, England
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22
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Blasig IE, Mertsch K, Haseloff RF. Nitronyl nitroxides, a novel group of protective agents against oxidative stress in endothelial cells forming the blood-brain barrier. Neuropharmacology 2002; 43:1006-14. [PMID: 12423670 DOI: 10.1016/s0028-3908(02)00180-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nitronyl nitroxides (NN) effectively decompose free radicals (. As brain endothelium, forming the blood-brain barrier (BBB), is both the main source and the target of reactive species during cerebral oxidative stress, we studied the effect of NN on brain endothelial cells injured by the mediator of oxidative stress H(2)O(2) (. H(2)O(2) caused hydroxyl radical generation, lipid peroxidation, membrane dysfunction, membrane leak and cell death, concentration dependently. Due to 0.5 mM H(2)O(2), oxy-radical-induced membrane phospholipid peroxidation (malondialdehyde) increased to 0.61+/-0.04 nmol/mg protein vs control (0.32+/-0.03, p<0.05), cells lost cytosolic proteins into the medium and viability decreased to 28+/-2% of control (p<0.05). Permeability through the endothelial monolayer (measure for the tightness of the BBB) rose to 250+/-40% after 0.15 mM H(2)O(2) (p<0.001). Addition of 10 microM of the NN 5,5-dimethyl-2,4-diphenyl-4-methoxy-2-imidazoline-3-oxide-1-oxyl (NN-2), 1 mM phenylbutyl nitrone (PBN), or 10 microM of the lazaroid U83836E improved cell viability during incubation with 0.5 mM H(2)O(2) to 57+/-1%, 49+/-2%, and 42+/-3% (p<0.05, vs drug-free H(2)O(2) group). The permeability enhancement by 0.15 mM H(2)O(2) was reduced to 171+/-21%, 170+/-25%, and 118+/-32% (p<0.05 vs drug-free H(2)O(2) group). Generally, the assumption is supported that during cerebral oxidative stress the protection should also be directed to the cells of the BBB, which can be provided by antioxidative approaches. NN represent a new group of antioxdatively acting cytoprotectiva improving the survival and function of the endothelium against oxidative stress.
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Affiliation(s)
- I E Blasig
- Forschungsinstitut für Molekulare Pharmakologie, Delbrück-Zentrum für Molekulare Medizin, Robert-Rössle-Str.10, 13125 Berlin, Germany.
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23
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Ren Y, Carretero OA, Garvin JL. Mechanism by which superoxide potentiates tubuloglomerular feedback. Hypertension 2002; 39:624-8. [PMID: 11882620 DOI: 10.1161/hy0202.103299] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The macula densa detects changes in NaCl concentration in tubular fluid and transmits a feedback signal, known as tubuloglomerular feedback (TGF), which helps to control glomerular afferent arteriole resistance. We and other investigators have reported that synthesis of NO in the macula densa inhibits TGF. NO can be scavenged by superoxide (O(-)(2)) to form peroxynitrite, effectively reducing the bioavailability of NO; there is growing evidence that O(-)(2) regulates vascular tone in the kidney. We hypothesized that O(-)(2) produced in the macula densa enhances TGF and this effect acts only in an autocrine manner within the cells of the macula densa. Afferent arterioles and attached macula densas from Sprague-Dawley rats were simultaneously microperfused in vitro and TGF response examined before and after perfusing the tubular lumen, bath, or vascular lumen with a superoxide scavenger. The macula densa was perfused with solutions containing either 5 mmol/L Na(+) and 3 mmol/L Cl(-) (low NaCl) or 80 mmol/L Na(+) and 77 mmol/L Cl(-) (high NaCl) while keeping pressure in the afferent arteriole constant at 60 mm Hg. When 10(-4) M Tempol, a stable membrane-permeant superoxide dismutase (SOD) mimetic, was added to the tubular lumen, it inhibited TGF by 56% (before Tempol: TGF, 3.2 +/- 0.3 microm; after Tempol: TGF, 1.4 +/- 0.2 microm; n=6; P<0.05, control versus Tempol). Adding Tempol to the bath inhibited TGF by 48% (before Tempol: TGF, 2.5 +/- 0.25 microm; after Tempol: TGF, 1.3 +/- 0.18 microm; n=6; P<0.05). However, adding Tempol to the vessel lumen did not change TGF response significantly (before Tempol: TGF, 2.7 +/- 0.37 microm; after Tempol: TGF, 3.2 +/- 0.25 microm; n=7; P=0.25). When 300 U/mL of the enzyme SOD, which is not membrane-permeant, was added to either the tubular lumen or bath, it had no effect on TGF response. Finally, to determine whether the effect of O(-)(2) in the macula densa is mediated by its scavenging of NO, 7-nitroindazole (7-NI) was added to the macula densa to inhibit neuronal nitric oxide synthase (nNOS). In the presence of 7-NI, Tempol had no effect (7-NI only: TGF, 3.0 +/- 0.4 microm; 7-NI plus Tempol: TGF, 2.8 +/- 0.5 microm; n=6; P=0.343). Our findings suggest that (1) reducing O(-)(2) increases the bioavailability of NO, which inhibits TGF, (2) both O(-)(2) and NO act within the macula densa, and (3) O(-)(2) appears to have no effect on its own.
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Affiliation(s)
- YiLin Ren
- Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI 48202, USA
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24
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Abstract
Nitric oxide (NO) is an important regulator of NaCl absorption by the thick ascending limb of the loop of Henle (THAL). The free radical superoxide (O(2)(-)) reacts with NO, decreasing its bioavailability. O(2)(-) is produced by mitochondria and various oxidases, some of which are present in the THAL. However, the ability of the THAL to produce O(2)(-) and its interaction with NO have not been studied. We hypothesized that NO bioavailability is decreased by O(2)(-). THALs were isolated and perfused and NO production was measured with an NO-selective microelectrode. Addition of L-Arg (250 micromol/L), but not D-arginine, to the bath increased NO release by 34.8 +/- 11.8 pA (n=7). The response to L-Arg was completely abolished by the NO synthase inhibitor L-NAME (n=7). Scavenging THAL O(2)(-) with the superoxide dismutase (SOD) mimetic Tempol (50 micromol/L) increased L-Arg-induced NO release. At all concentrations of L-Arg tested (50, 100, 250, 500, and 750 micromol/L), further addition of Tempol to the bath significantly increased NO release by THALs. Addition of SOD (300 U/mL) to the bath increased L-Arg-induced NO levels by 82% (n=5; P<0.02). Pretreatment of THALs with the SOD inhibitor diethyl-dithiocarbamate (250 micromol/L) blunted L-Arg-induced NO release by 63% compared with untreated tubules (n=5; P<0.05). Finally, we tested the effect of Tempol on NO-induced inhibition of THAL chloride transport. Addition of L-Arg decreased THAL Cl(-) absorption by 35%. Subsequent addition of Tempol (50 micromol/L) to the bath further decreased Cl(-) absorption by 35% (n=6; P<0.05). We conclude that NO bioavailability in the THAL is decreased by O(2)(-). In addition, we believe our studies are the first to show that endogenous O(2)(-) may act as a physiological regulator of nephron NaCl transport.
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Affiliation(s)
- Pablo A Ortiz
- Division of Hypertension and Vascular Research, Department of Internal Medicine, Henry Ford Hospital, Detroit, MI 48202, USA
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25
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Raikov ZD, Raikova ET, Atanasov AT. Nitric oxide and free stable nitroxyl radicals in the mechanism of biological action of the spin-labeled compounds. Med Hypotheses 2001; 57:302-5. [PMID: 11516220 DOI: 10.1054/mehy.2001.1284] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A comparison of more important physical, chemical and biological properties of the nitric oxide (NO) and free stable nitroxyl radicals (nitroxides) on the base of their structural similarity is made in the article. The active moiety in the nitroxide molecule represents a sterically hindered nitric oxide. The mechanisms of biological action of the nitroxides and especially of their derivatives with antitumor agents from the groups of nitrogen mustards, nitrosoureas, aziridines and triazenes (spin-labeled compounds) is explained through the biological activities of sterically hindered NO. Similarly to NO, nitroxides also can react with superoxide anion radical (O(2)(-)), they possess superoxide dismutase (SOD) mimetic action. While the interaction of NO with O(2)(-)yields very toxic peroxynitrite (ONOO(-)), its formation is strongly limited in the presence of a nitroxide. It is known that the nitrosourea antitumor drugs, like lomustine (CCNU) and carmustine (BCNU), showed high general toxicity, one of the reasons for that probability is the formation of NO, and subsequently of ONOO(-), during their metabolism. The biological investigations of the nitroxides showed their considerably lower general toxicity that could be explained with the SOD-mimetic action of the nitroxide present in their molecule.
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Affiliation(s)
- Z D Raikov
- Department of Chemistry and Biochemistry, Thracian University, Medical Institute, 6000 Stara Zagora, Bulgaria
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26
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Blasig IE, Giese H, Schroeter ML, Sporbert A, Utepbergenov DI, Buchwalow IB, Neubert K, Schönfelder G, Freyer D, Schimke I, Siems WE, Paul M, Haseloff RF, Blasig R. *NO and oxyradical metabolism in new cell lines of rat brain capillary endothelial cells forming the blood-brain barrier. Microvasc Res 2001; 62:114-27. [PMID: 11516240 DOI: 10.1006/mvre.2001.2318] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To investigate the relevance of *NO and oxyradicals in the blood-brain barrier (BBB), differentiated and well-proliferating brain capillary endothelial cells (BCEC) are required. Therefore, rat BCEC (rBCEC) were transfected with immortalizing genes. The resulting lines exhibited endothelial characteristics (factor VIII, angiotensin-converting enzyme, high prostacyclin/thromboxane release rates) and BBB markers (gamma-glutamyl transpeptidase, alkaline phosphatase). The control line rBCEC2 (mock transfected) revealed fibroblastoid morphology, less factor VIII, reduced gamma-glutamyl transpeptidase, weak radical defence, low prostanoid metabolism, and limited proliferation. Lines transfected with immortalizing genes (especially rBCEC4, polyoma virus large T antigen) conserved primary properties: epitheloid morphology, subcultivation with high proliferation rate under pure culture conditions, and powerful defence against reactive oxygen species (Mn-, Cu/Zn-superoxide dismutase, catalase, glutathione peroxidase, glutathione) effectively controlling radical metabolism. Only 100 microM H2O2 overcame this defence and stimulated the formation of eicosanoids similarly as in primary cells. Some BBB markers were expressed to a lower degree; however, cocultivation with astrocytes intensified these markers (e.g., alkaline phosphatase) and paraendothelial tightness, indicating induction of BBB properties. Inducible NO synthase was induced by a cytokine plus lipopolysaccharide mixture in all lines and primary cells, resulting in *NO release. Comparing the cell lines obtained, rBCEC4 are stable immortalized and reveal the best conservation of properties from primary cells, including enzymes producing or decomposing reactive species. These cells can be subcultivated in large amounts and, hence, they are suitable to study the role of radical metabolism in the BBB and in the cerebral microvasculature.
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Affiliation(s)
- I E Blasig
- Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 10315, Berlin, Germany.
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27
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Zöllner S, Aberle S, Harvey SE, Polokoff MA, Rubanyi GM. Changes of endothelial nitric oxide synthase level and activity during endothelial cell proliferation. ENDOTHELIUM : JOURNAL OF ENDOTHELIAL CELL RESEARCH 2001; 7:169-84. [PMID: 10912911 DOI: 10.3109/10623320009165315] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The goal of this study was to investigate the effect of endothelial cell proliferation on the expression and activity of endothelial nitric oxide synthase (eNOS). Bovine atrial endothelial cells (BAtEC) were studied between day 1 and 6 after seeding. During this period the number of cells in S-phase decreased progressively, while cell number and protein content increased, reaching a maximum at confluence (day 4). Expression of eNOS (determined by ELISA) and eNOS activity (determined by L-arginine to L-citrulline conversion) increased with culture duration with a maximum at confluence. Nitric oxide (*NO) release from BAtEC was determined after stimulation with Ca2+ ionophore A23187 (10 microM, 30 min) by .NO chemiluminescence in the absence of a chemical reduction system. Total *NO release (measured in the presence of 100 U/ml superoxide dismutase) did not change with state of cell proliferation/growth, whereas "bioavailable" *NO (measured in the absence of superoxide dismutase) was low in highly proliferating BAtEC. Relative eNOS activity (.NO and L-citrulline production per eNOS protein) was highest in proliferating BAtEC. The novel finding of this study is that the specific eNOS activity is upregulated in proliferating BAtEC and downregulated in quiescent BAtEC. The amount of "bioavailable" *NO is determined by eNOS activity and *NO inactivation (probably by superoxide), both high in proliferating BAtEC.
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Affiliation(s)
- S Zöllner
- Cardiovascular Department, Berlex Biosciences, Richmond, CA 94804, USA
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28
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Buehler PW, Mehendale S, Wang H, Xie J, Ma L, Trimble CE, Hsia CJ, Gulati A. Resuscitative effects of polynitroxylated alphaalpha-cross-linked hemoglobin following severe hemorrhage in the rat. Free Radic Biol Med 2000; 29:764-74. [PMID: 11053778 DOI: 10.1016/s0891-5849(00)00383-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
alphaalpha-Cross-linked hemoglobin (alphaalphaHb) is an example of a hemoglobin-based oxygen carrier (HBOC) with significant cardiovascular activity. This may compromise the safety and efficacy of this HBOC by causing systemic hypertension and reducing blood flow to some organs. The present work is based on the hypothesis that incorporating antioxidant activity into an HBOC in the form of a covalently attached nitroxide may prevent these effects. We have tested this hypothesis by adding antioxidant activity to alphaalphaHb with 2,2,6,6-tetramethyl-piperidinyl-1-oxyl (Tempo) to create polynitroxylated alphaalphaHb (PN-alphaalphaHb). The new compound PN-alphaalphaHb acts as an antioxidant in our in vitro and in vivo assays. In this study urethane-anesthetized rats were hemorrhaged to a mean arterial pressure (MAP) of 35-40 mmHg and maintained for 30 min. Animals were resuscitated with solutions of (1) 10% PN-alphaalphaHb (43 mmHg), (2) 10% alphaalphaHb (43 mmHg), (3) 7.5% albumin (43 mmHg), (4) 300% Ringers lactate (RL), and (5) 0. 9% normal saline equal to the shed blood volume (SBV). Hemodynamics and regional blood circulation was measured at baseline, following hemorrhage, and at 30 and 60 min postresuscitation using a radioactive microsphere technique. Base deficit (BD) was measured at baseline, following hemorrhage, and at 60 min following resuscitative fluid infusion. Finally survival was determined as the time following resuscitation until secession of heart rhythm. Saline and 300% RL resuscitation did not improve BD, systemic hemodynamics, or regional blood circulation. PN-alphaalphaHb, alphaalphaHb, and albumin significantly improved these parameters, however, only PN-alphaalphaHb and alphaalphaHb improved survival. PN-alphaalphaHb was found to be less hypertensive than alphaalphaHb due to blunted increases in both cardiac output and systemic vascular resistance. This study demonstrates that, by using alphaalphaHb as a scaffold for polynitroxylation, improvement in vasoactivity and resuscitative efficacy may be possible. In conclusion, the addition of antioxidant activity in the form of polynitroxylation of a low molecular weight Hb (alphaalphaHb) may create a safe and efficacious resuscitative fluid.
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Affiliation(s)
- P W Buehler
- Department of Pharmaceutics and Pharmacodynamics, The University of Illinois, Chicago, IL 60612, USA
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29
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Cauwels A, Van Molle W, Janssen B, Everaerdt B, Huang P, Fiers W, Brouckaert P. Protection against TNF-induced lethal shock by soluble guanylate cyclase inhibition requires functional inducible nitric oxide synthase. Immunity 2000; 13:223-31. [PMID: 10981965 DOI: 10.1016/s1074-7613(00)00022-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hypotension and shock observed in sepsis, SIRS, and tumor necrosis factor (TNF) or cytokine-based cancer treatment are the consequence of excessive nitric oxide (NO) production and subsequent soluble guanylate cyclase (sGC)-mediated vascular smooth muscle relaxation. We demonstrate here that, while NO synthase (NOS) inhibitors exacerbated toxicity, inhibitors of sGC activation protected against TNF-induced lethality, bradycardia, and hypotension. Importantly, sGC inhibition did not interfere with the antitumor activity of TNF. Using NOS inhibitors or iNOS-deficient animals, we furthermore observed that no protection against TNF toxicity could be obtained in the absence of NO. These data imply that iNOS- (and not eNOS-) derived NO is an endogenous protective molecule indispensable to survive a TNF challenge and exerting this beneficial effect via sGC-independent mechanisms.
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Affiliation(s)
- A Cauwels
- MPET, Department of Molecular Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, Belgium.
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30
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Saetre T, Höiby EA, Aspelin T, Lermark G, Egeland T, Lyberg T. Aminoethyl-isothiourea, a nitric oxide synthase inhibitor and oxygen radical scavenger, improves survival and counteracts hemodynamic deterioration in a porcine model of streptococcal shock. Crit Care Med 2000; 28:2697-706. [PMID: 10966238 DOI: 10.1097/00003246-200008000-00003] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To test the effect of a continuous infusion of the nitric oxide (NO) synthase (S) inhibitor aminoethyl-isothiourea (AE-ITU) on survival time, hemodynamics, and oxygen transport in a porcine model of live group A streptococcal (GAS) sepsis. Furthermore, to examine the role of endothelin-1, histamine, and reactive oxygen species (ROS) in streptococcal shock. DESIGN Prospective, randomized trial. SETTING Laboratory at a university hospital. SUBJECTS Twenty-eight pigs with an average weight of 25 kg. INTERVENTIONS Sixteen animals received a continuous infusion of live Streptococcus pyogenes 1.3 x 10(10) colony forming units/hr: eight received fluids only, and the other eight received an intravenous infusion of AE-ITU 10 mg/kg/hr starting 30 mins before the GAS challenge. Six control pigs received AE-ITU 10 mg/kg/hr iv for 5 hrs. Another six animals received half the dose of GAS over 5 hrs. MEASUREMENTS AND MAIN RESULTS GAS infusion caused a rapid increase in pulmonary, hepatic, and systemic vascular resistance, followed by hypotension with a 90% lethality at 4 hrs. Treatment with AE-ITU increased 4-hr survival in septic animals from 1/8 to 8/8 and 5-hr survival from 0/8 to 5/8, prevented hypotension, and increased urine output. AE-ITU attenuated the decrease in cardiac output, liver blood flow, and oxygen delivery, and hepatic arterial blood flow as a fraction of cardiac output increased (all p < .05). Plasma nitrate/nitrite levels decreased in all animals. Inducible NOS and endothelial constitutive NOS activities in liver, gut, and lung were not increased during sepsis, nor were they decreased after AE-ITU. Plasma levels of endothelin-1 and methylhistamine increased in all septic animals and were not modified by AE-ITU. AE-ITU prevented the increase in monocyte ROS production caused by GAS. In control animals, AE-ITU caused an increase in mean arterial pressure, liver blood flow, and oxygen delivery. CONCLUSIONS In this model of porcine GAS-induced septic shock, which was not associated with enhanced NO production, infusion of the NOS inhibitor AE-ITU prolonged survival, prevented hypotension, and improved cardiac contractility, organ perfusion, and tissue oxygenation. These beneficial effects of AE-ITU might be a result of the combined effect of ROS scavenging and modulation of local NO production, thus improving the balance of vasodilator and vasoconstrictor forces and reducing oxidative stress.
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Affiliation(s)
- T Saetre
- Research Forum, Ullevaal University Hospital, Oslo, Norway.
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Zacharowski K, Olbrich A, Cuzzocrea S, Foster SJ, Thiemermann C. Membrane-permeable radical scavenger, tempol, reduces multiple organ injury in a rodent model of gram-positive shock. Crit Care Med 2000; 28:1953-61. [PMID: 10890647 DOI: 10.1097/00003246-200006000-00044] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE An enhanced formation of reactive oxygen species contributes to the multiple organ dysfunction syndrome (MODS) caused by endotoxin. We have recently discovered that two cell wall components, namely lipoteichoic acid (LTA) and peptidoglycan (PepG) of the gram-positive bacterium, Staphylococcus aureus, synergize to cause shock and MODS in the rat. Here, we investigate the effects of a membrane-permeable radical scavenger (tempol) on the circulatory failure and MODS (kidney, liver, lung) caused by coadministration of LTA (3 mg/kg i.v.) and PepG (10 mg/kg i.v.) in the anesthetized rat. DESIGN Prospective, randomized study. SETTING University-based research laboratory. SUBJECTS Thirty-four anesthetized, male Wistar rats. INTERVENTIONS After surgical preparation, anesthetized rats were observed for 6 hrs. Control rats were given vehicle (control plus saline, 2 mL/kg bolus injection, followed by an infusion of 1.5 mL/kg i.v., n = 6) or tempol (control plus tempol, 100 mg/kg i.v. bolus injection, followed by an infusion of 30 mg/kg i.v., n = 6). Gram-positive septic shock was induced by coadministration of LTA (3 mg/kg i.v.) and PepG (10 mg/kg i.v.) (LTA/PepG plus saline, n = 12). Another group of rats was pretreated with tempol before shock was induced (LTA/PepG plus tempol, 100 mg/kg i.v. bolus injection, 15 mins before LTA/PepG administration, followed by an infusion of 30 mg/kg i.v., n = 10). MEASUREMENTS AND MAIN RESULTS Within 6 hrs, administration of LTA/PepG resulted in hypotension, acute renal dysfunction, hepatocellular injury, pancreatic injury, and increased plasma concentrations of nitrite/nitrate. Pretreatment of rats with tempol augmented the hypotension but attenuated the renal dysfunction and the hepatocellular injury/dysfunction caused by LTA/PepG. Tempol did not affect the increase in nitrite/nitrate caused by LTA/PepG. CONCLUSIONS These results imply that an enhanced formation of reactive oxygen species (including superoxide anions) contributes to the kidney and liver injury and dysfunction caused by LTA/PepG in the anesthetized rat.
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Affiliation(s)
- K Zacharowski
- William Harvey Research Institute, St. Bartholomew's and The Royal London School of Medicine and Dentistry, UK
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Rak R, Chao DL, Pluta RM, Mitchell JB, Oldfield EH, Watson JC. Neuroprotection by the stable nitroxide Tempol during reperfusion in a rat model of transient focal ischemia. J Neurosurg 2000; 92:646-51. [PMID: 10761655 DOI: 10.3171/jns.2000.92.4.0646] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The use of thrombolytic agents in the treatment of stroke has yielded surprisingly modest success, possibly because of reperfusion injury mediated by reactive oxygen species (ROS). Therefore, scavenging ROS may be of therapeutic value in the treatment of stroke. Nitroxides are low-weight superoxide dismutase mimics, which allows them to act as cell-permeable antioxidants. In this study the nitroxide 4-hydroxy-2,2,6,6,-tetramethylpiperidine-1-oxyl (Tempol) is investigated to determine its ability to reduce reperfusion injury. METHODS Male Sprague-Dawley rats weighing between 280 g and 350 g underwent middle cerebral artery occlusion with an intraluminal suture for 60 minutes. Regional cerebral blood flow, blood pressure, cerebral temperature, and rectal temperature were monitored during the procedure. After reperfusion, the animals were randomized to groups receiving blinded intravenous administration of either Tempol (10 mg/kg; eight animals) or vehicle (eight animals) over the first 20 minutes of reperfusion (Study I). In a second study to determine dose dependency, animals were randomized to groups receiving Tempol (20 mg/kg; eight animals), low-dose Tempol (5 mg/kg; eight animals), or vehicle (eight animals; Study II). The rats were killed after 4 hours of reperfusion, and brain sections were stained with 2,3,5 triphenyltetrazolium chloride. Infarct volumes were measured using digital imaging. Animals receiving Tempol had significantly reduced infarct volumes at doses of 20 mg/kg and 10 mg/kg compared with controls (49.01+/-18.22% reduction [p = 0.003] and 47.47+/-34.57 [p = 0.02], respectively). No significant differences in the physiological variables measured were observed between groups. CONCLUSIONS Tempol provides significant neuroprotection after reperfusion in a rat model of transient focal ischemia. These results support the importance of ROS in reperfusion injury and encourage further study of this molecule as a therapeutic agent following thrombolysis.
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Affiliation(s)
- R Rak
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
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McDonald MC, Zacharowski K, Bowes J, Cuzzocrea S, Thiemermann C. Tempol reduces infarct size in rodent models of regional myocardial ischemia and reperfusion. Free Radic Biol Med 1999; 27:493-503. [PMID: 10490268 DOI: 10.1016/s0891-5849(99)00100-8] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Reactive oxygen species (ROS) contribute to ischemia-reperfusion injury of the heart. This study investigates the effects of tempol, a membrane-permeable radical scavenger on (i) the infarct size caused by regional myocardial ischemia and reperfusion of the heart in vivo (rat, rabbit) and in vitro (rat), and (ii) the cell injury caused by hydrogen peroxide (H2O2) in rat cardiac myoblasts (H9c2 cells). In the anesthetized rat, tempol reduced the infarct size caused by regional myocardial ischemia (25 min) and reperfusion (2 h) from 60 +/- 3% (control, n = 8) to 24 +/- 5% (n = 6, p < .05). In the anesthetized rabbit, tempol also attenuated the infarct size caused by myocardial ischemia (45 min) and reperfusion (2 h) from 59 +/- 3% (control, n = 6) to 39 +/- 5% (n = 5, p < .05). Regional ischemia (35 min) and reperfusion (2 h) of the isolated, buffer-perfused heart of the rat resulted in an infarct size of 54 +/- 4% (control n = 7). Reperfusion of hearts with buffer containing tempol (n = 6) caused a 37% reduction in infarct size (n = 6, p < .05). Pretreatment of rat cardiac myoblasts with tempol attenuated the impairment in mitochondrial respiration caused by H2O2 (1 mM for 4 h). Thus, the membrane-permeable radical scavenger tempol reduces myocardial infarct size in rodents.
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Affiliation(s)
- M C McDonald
- The William Harvey Research Institute, St. Bartholomew's and The Royal London School of Medicine and Dentistry, United Kingdom
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Hahn SM, Sullivan FJ, DeLuca AM, Bacher JD, Liebmann J, Krishna MC, Coffin D, Mitchell JB. Hemodynamic effect of the nitroxide superoxide dismutase mimics. Free Radic Biol Med 1999; 27:529-35. [PMID: 10490272 DOI: 10.1016/s0891-5849(99)00099-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species play critical roles in a number of physiologic and pathologic processes. Nitroxides are stable free radical compounds that possess superoxide dismutase (SOD) mimetic activity and have been shown to protect against the toxicity of reactive oxygen species in vitro and in vivo. Tempol, a cell-permeable hydrophilic nitroxide, protects against oxidative stress and also is an in vitro and in vivo radioprotector. In the course of evaluating the pharmacology and toxicity of the nitroxides, Tempol and another nitroxide, 3-carbamoyl-PROXYL (3-CP), were administered intravenously in various concentrations to miniature swine. Tempol caused dose-related hypotension accompanied by reflex tachycardia and increased skin temperature. Invasive hemodynamic monitoring with Swan Ganz catheterization (SGC) confirmed the potent vasodilative effect of Tempol. However, 3-CP had no effect on porcine blood pressure. The hemodynamic effects of Tempol and 3-CP are discussed in the context of differential catalytic rate constants for superoxide disumation that may impact systemic nitric oxide (NO) levels and lead to vasodilation. These findings are consistent with a role for the superoxide ion in the modulation of blood pressure and have potential implications for the systemic use of nitroxides.
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Affiliation(s)
- S M Hahn
- Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, USA
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Singh RJ, Hogg N, Joseph J, Konorev E, Kalyanaraman B. The peroxynitrite generator, SIN-1, becomes a nitric oxide donor in the presence of electron acceptors. Arch Biochem Biophys 1999; 361:331-9. [PMID: 9882464 DOI: 10.1006/abbi.1998.1007] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
SIN-1 has been used, in vitro, to simultaneously generate nitric oxide (*NO) and superoxide (O*-2). However, the pharmacological activity of SIN-1 resembles that of a *NO donor. SIN-1 decays by a three-step mechanism. After initial isomerization to an open ring form, SIN-1A reduces oxygen by a one-electron transfer reaction to give O*-2 and the SIN-1 cation radical, which decomposes to form SIN-1C and *NO. Here we report that one-electron oxidizing agents, in addition to oxygen, can oxidize SIN-1A, resulting in the release of *NO without the concomitant formation of O*-2. We demonstrate that easily reducible nitroxides, such as the nitronyl and imino nitroxides, are able to oxidize SIN-1. Biological oxidizing agents such as ferricytochrome c also stimulate *NO production from SIN-1. In addition, decomposition of SIN-1 by human plasma or by the homogenate of rat liver, kidney, and heart tissues results in the formation of *NO. Our findings suggest that SIN-1 may react with heme proteins and other electron acceptors in biological systems to produce *NO. Thus, at the relatively low in vivo oxygen concentrations, SIN-1 is likely to behave more like an *NO donor than a peroxynitrite donor. The relevance of this reaction to myocardial protection afforded by SIN-1 in ischemia/reperfusion-induced injury is discussed.
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Affiliation(s)
- R J Singh
- Biophysics Research Institute, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin, 53226, USA
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Leach M, Frank S, Olbrich A, Pfeilschifter J, Thiemermann C. Decline in the expression of copper/zinc superoxide dismutase in the kidney of rats with endotoxic shock: effects of the superoxide anion radical scavenger, tempol, on organ injury. Br J Pharmacol 1998; 125:817-25. [PMID: 9831920 PMCID: PMC1571036 DOI: 10.1038/sj.bjp.0702123] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Endotoxaemia causes an enhanced formation of reactive oxygen species (ROS) which contribute to the multiple organ dysfunction syndrome (MODS) in septic shock. Here we investigate (i) the effects of endotoxin on the expression of two isoforms of superoxide dismutase (SOD), namely Cu/Zn-SOD (cytosol) and Mn-SOD (mitochondria) in the rat kidney, and (ii) the effects of the radical scavenger tempol on the MODS caused by lipopolysaccharide (LPS, E. coli, 6 mg kg(-1) i.v.) in the rat. 2. Endotoxaemia resulted in a rapid, but transient, decline in the expression of both mRNA and protein of Cu/Zn-SOD as well as an increase in the expression of the mRNA of Mn-SOD in the kidney. Endotoxaemia for 6 h also caused hypotension, acute renal dysfunction, hepatocellular injury, pancreatic injury and an increase in the plasma levels of nitrite/nitrate. 3. Pretreatment of rats with tempol (100 mg kg(-1) i.v. bolus injection, 15 min prior to LPS followed by an infusion of 30 mg kg(-1) i.v., n=9) did not affect the circulatory failure, but attenuated the renal dysfunction and the hepatocellular injury/dysfunction caused by LPS. Tempol did not affect the rise in nitrite/nitrate caused by endotoxin. 4. These results imply that an enhanced formation of ROS (including superoxide anions) in conjunction with inadequate defences against such ROS contributes to the injury and dysfunction of the kidney and the liver in endotoxic shock.
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Affiliation(s)
- M Leach
- The William Harvey Research Institute, St. Bartholomew's and The Royal London School of Medicine and Dentistry, UK
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