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Luchetti F, Canonico B, Cesarini E, Betti M, Galluzzi L, Galli L, Tippins J, Zerbinati C, Papa S, Iuliano L. 7-Ketocholesterol and 5,6-secosterol induce human endothelial cell dysfunction by differential mechanisms. Steroids 2015; 99:204-11. [PMID: 25697053 DOI: 10.1016/j.steroids.2015.02.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/05/2015] [Accepted: 02/06/2015] [Indexed: 11/16/2022]
Abstract
7-Ketocholesterol and 5,6-secosterol are cholesterol autoxidation products generated under oxidative stress by two distinct mechanisms. They are present in atherosclerotic plaques and are candidate players in the disease initiation and progression. While 7-ketocholesterol affects at cellular level, in particular apoptosis, are well known and reported on diverse cell lines, 5,6-secosterol is a recently discovered oxysterol with relatively few reports on the potential to affect endothelial cell functions. Endothelial cells have a central role in cardiovascular disease as they provide the barrier between blood and the vessel wall where atherosclerosis starts and progresses. Insults to endothelial cells provoke their dysfunction favoring pro-atherogenic and pro-thrombotic effects. In the present work, we tested 7-ketocholesterol and 5,6-secosterol on endothelial cells - focusing on apoptosis and the associated mitochondrial/lysosome alterations - and on endothelial function using the in vitro model of arterial relaxation of aortic rings. Our data provide evidence that 7-ketocholesterol and 5,6-secosterol are efficient instigators of apoptosis, which for 5,6-secosterol is associated to PKC and p53 up-regulation. In addition 5,6-secosterol is a potent inhibitor of endothelial-dependent arterial relaxation through PKC-dependent mechanisms. This may contribute to pro-atherogenic and pro-thrombotic mechanisms of 5,6-secosterol and highlights the role of cholesterol autoxidation in cardiovascular disease.
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Affiliation(s)
- Francesca Luchetti
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy.
| | - Barbara Canonico
- Department of Earth, Life and Environmental Science, University of Urbino "Carlo Bo", Urbino, Italy
| | - Erica Cesarini
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Michele Betti
- Department of Earth, Life and Environmental Science, University of Urbino "Carlo Bo", Urbino, Italy
| | - Luca Galluzzi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Laura Galli
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - John Tippins
- Division of Cell & Molecular Biology, Biochemistry Building, Imperial College, London, UK
| | - Chiara Zerbinati
- Department of Medico-Surgical Sciences and Biotechnologies Vascular Biology, Atherothrombosis & Mass Spectrometry, Sapienza University of Rome, Latina, Italy
| | - Stefano Papa
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Luigi Iuliano
- Department of Medico-Surgical Sciences and Biotechnologies Vascular Biology, Atherothrombosis & Mass Spectrometry, Sapienza University of Rome, Latina, Italy
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Role of oxidative and nitrosative stress in autogenous bone grafts to the mandible using guided bone regeneration and a deproteinized bovine bone material. J Craniomaxillofac Surg 2013; 42:560-7. [PMID: 24035733 DOI: 10.1016/j.jcms.2013.07.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 06/03/2013] [Accepted: 07/31/2013] [Indexed: 11/22/2022] Open
Abstract
UNLABELLED The aim of this study was to evaluate the role of oxidative and nitrosative stress in autogenous bone grafts to the mandible based on immunohistochemical analysis. MATERIAL AND METHODS Using a well-established sheep model autogenous bone grafts were harvested form the iliac bone. A combination of a Collagen Membrane (CM) and Deproteinized Bovine Bone Material (DBBM) was used to cover the bone graft (Experiment 2). This modification was compared with simple onlay bone grafts (Experiment 1). Immunohistochemically, the expression of specific stable degradation products of oxidative and nitrosative stress was compared between the two experimental groups. RESULTS Specific markers for oxidative and nitrosative stress showed statistically significant differences in expression in the different experimental groups. The influence of oxidative and nitrosative stress on osteoblasts (OB), osteoclasts (OC), and osteocytes (OCy) was analysed. Experiment 2 showed increased expression of markers in OB and decreased expression in OC. CONCLUSIONS Taking the result of this study and reports from the literature into consideration grafts in Experiment 2 showed less resorption and atrophy, higher activity of OB and inhibition of OC, and less expression of Reactive Oxygen and Nitrogen Species (RONS) as markers of oxidative stress within the graft. These data illustrate the improved remodelling processes in grafts using CM and DBBM.
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Alvarez Y, Briones AM, Balfagón G, Alonso MJ, Salaices M. Hypertension increases the participation of vasoconstrictor prostanoids from cyclooxygenase-2 in phenylephrine responses. J Hypertens 2005; 23:767-77. [PMID: 15775781 DOI: 10.1097/01.hjh.0000163145.12707.63] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The present study was designed to analyse whether hypertension alters the involvement of cyclooxygenase-2-derived mediators in phenylephrine-induced vasoconstrictor responses. METHODS Vascular reactivity experiments were performed in aortic segments from normotensive, Wistar-Kyoto, and spontaneously hypertensive rats (SHR); protein expression was measured by western blot and/or immunohistochemistry, and prostaglandin F2alpha (PGF2alpha), 8-isoprostane and prostacyclin release were determined by enzyme immunoassay commercial kits. RESULTS The protein synthesis inhibitor dexamethasone (1 micromol/l), the non-selective cyclooxygenase inhibitor indomethacin (10 micromol/l), the selective cyclooxygenase-2 inhibitor NS 398 (1 micromol/l), and the thromboxane A2/prostaglandin H2 (TP) receptor antagonist SQ 29,548 (1 micromol/l), reduced the concentration-response curves to phenylephrine more in segments from hypertensive than from normotensive rats; however, the thromboxane A2 (TxA2) synthase inhibitors furegrelate (10 micromol/l) and OKY 046 (1 and 10 micromol/l) had no effect in either strain. Removing endothelium or adding dexamethasone almost abolished the NS 398 effect. Cyclooxygenase-2 protein expression, which was reduced by dexamethasone, was higher in aorta from hypertensive animals. In both strains cyclooxygenase-2 was localized mainly in endothelial cells and adventitial fibroblasts. 13,14-Dihydro-15-keto-PGF2alpha, 6-keto-PGF1alpha and 8-isoprostane levels were greater in the medium from hypertensive than from normotensive rats; NS 398 decreased levels of the three metabolites studied only in the medium from SHR. CONCLUSIONS PGF2alpha and 8-isoprostane seem to be involved in the response to phenylephrine in rat aorta; this involvement is greater in hypertensive rats, probably due to a higher endothelial induction of cyclooxygenase-2.
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Affiliation(s)
- Yolanda Alvarez
- Departamento de Farmacología y Terapéutica bDepartamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Spain
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Marlière S, Cracowski JL, Hakim A, Stanke-Labesque F, Hoffmann P, Bessard G. Vascular effects of 15-F2t-isoprostane in spontaneously hypertensive rats. Can J Physiol Pharmacol 2005; 83:453-8. [PMID: 16049544 DOI: 10.1139/y05-027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
F2-isoprostanes are a family of compounds derived from arachidonic acid by free radical-catalyzed peroxidation. Among F2-isoprostanes, 15-F2t-IsoP is a vasoconstrictor in animal and human vascular beds. Several recent studies found increased 15-F2t-IsoP levels in animal models of hypertension. However, no data is available on the vascular effect of 15-F2t-IsoP in such models. The contractile responses of 15-F2t-IsoP (10–9 to 3 × 10–5 mol/L) were tested on rat thoracic aortic rings in spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto (WKY) rats. The contraction induced by 15-F2t-IsoP was not significantly different in aortic rings from WKY rats and SHR (Emax 139% ± 5% vs. 134% ± 6%, respectively) and was mediated through thromboxane A2–prostaglandin H2 receptor activation as shown by the rightward shift of the concentration-contraction curves in presence of GR 32191, a specific thromboxane A2–prostaglandin H2 receptor antagonist. Endothelial denudation increased the maximal contraction compared to intact rings induced by 15-F2t-IsoP in both WKY rats (170% ± 20% vs. 139% ± 5%, p < 0.05) and SHR (194% ± 11% vs. 134% ± 6%, p < 0.01), whereas pretreatment with Nω-nitro-L-arginine (10–4 mol/L) or with indomethacin (10–5 mol/L) increased the maximal contraction to 15-F2t-IsoP in WKY rats but not in SHR. SHRs treated with an angiotensin-converting enzyme inhibitor, enalapril, for four weeks showed decreased maximal contraction to 15-F2t-IsoP in vessels with and without endothelium compared with untreated SHR. In conclusion, 15-F2t-IsoP-induced vasoconstriction is similar in SHR compared with WKY rats. Endothelium modulates 15-F2t-IsoP contraction in both strains. However, whereas this effect is mediated through nitric oxide- and cyclooxygenase-dependent pathways in WKY rats, other mediators are implicated in SHR. Key words: isoprostane, hypertension, lipid peroxidation, vascular reactivity, angiotensin-converting enzyme (ACE) inhibitors.
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MESH Headings
- Animals
- Antihypertensive Agents/therapeutic use
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Cyclooxygenase Inhibitors/pharmacology
- Dinoprost/analogs & derivatives
- Dinoprost/pharmacology
- Dose-Response Relationship, Drug
- Enalapril/therapeutic use
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Hypertension/drug therapy
- Hypertension/metabolism
- Hypertension/physiopathology
- In Vitro Techniques
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Vasoconstrictor Agents/pharmacology
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Angulo J, Cuevas P, La Fuente JM, Pomerol JM, Ruiz-Castañé E, Puigvert A, Gabancho S, Fernández A, Ney P, Sáenz de Tejada I. Regulation of human penile smooth muscle tone by prostanoid receptors. Br J Pharmacol 2002; 136:23-30. [PMID: 11976264 PMCID: PMC1762108 DOI: 10.1038/sj.bjp.0704675] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We have characterized the prostanoid receptors involved in the regulation of human penile arterial and trabecular smooth muscle tone. Arachidonic acid induced relaxation of human corpus cavernosum strips (HCCS) that was blocked by the cyclo-oxygenase inhibitor, indomethacin, and augmented by the thromboxane receptor (TP) antagonist, SQ29548, suggesting that endogenous production of prostanoids regulates penile smooth muscle tone. TP-receptors mediate contraction of HCCS and penile resistance arteries (HPRA), since the agonist of these receptors, U46619, potently contracted HCCS (EC50 8.3+/-2.8 nM) and HPRA (EC50 6.2+/-2.2 nM), and the contractions produced by prostaglandin F(2alpha) at high concentrations (EC50 6460+/-3220 nM in HCCS and 8900+/-6700 nM in HPRA) were inhibited by the selective TP-receptor antagonist, SQ29548 (0.02 microM). EP-receptors are responsible for prostanoid-induced relaxant effects in HCCS because only prostaglandin E1 (PGE1), prostaglandin E2 and the EP2/EP4-receptor agonist, butaprost, produced consistent relaxation of this tissue (EC50 93.8+/-31.5, 16.3+/-3.8 and 1820+/-1284 nM, respectively). In HPRA, both prostacyclin and PGE1 (EC50 60.1+/-18.4 and 109.0+/-30.9 nM, respectively) as well as the selective IP receptor agonist, cicaprost, and butaprost (EC50 25.2+/-15.2 and 7050+/-6020 nM, respectively) caused relaxation, suggesting co-existence of IP- and EP-receptors (EP2 and/or EP4). In summary, endogenous production of prostanoids may regulate penile smooth muscle contractility by way of specific receptors. TP-receptors mediate contraction in HCCS and HPRA, while the relaxant effects of prostanoids are mediated by EP2- and/or EP4-receptors in HCCS and by EP- and IP-receptors in HPRA.
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MESH Headings
- Alprostadil/pharmacology
- Arachidonic Acid/pharmacology
- Arteries/drug effects
- Arteries/physiology
- Cyclic AMP/metabolism
- Dinoprost/pharmacology
- Humans
- In Vitro Techniques
- Male
- Muscle Contraction/drug effects
- Muscle Relaxation/drug effects
- Muscle Tonus
- Muscle, Smooth/drug effects
- Muscle, Smooth/metabolism
- Muscle, Smooth/physiology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Penis/blood supply
- Penis/metabolism
- Penis/physiology
- Prostaglandins/biosynthesis
- Prostaglandins/pharmacology
- Receptors, Prostaglandin/agonists
- Receptors, Prostaglandin/antagonists & inhibitors
- Receptors, Prostaglandin/physiology
- Vascular Resistance
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Affiliation(s)
- Javier Angulo
- Fundación para la Investigación y el Desarrollo en Andrología, Madrid, Spain
- Departamento de Investigación, Hospital Ramón y Cajal, Madrid, Spain
| | - Pedro Cuevas
- Departamento de Investigación, Hospital Ramón y Cajal, Madrid, Spain
| | - Jose M La Fuente
- Fundación para la Investigación y el Desarrollo en Andrología, Madrid, Spain
| | - Jose M Pomerol
- Fundación para la Investigación y el Desarrollo en Andrología, Madrid, Spain
| | | | - Ana Puigvert
- Fundación para la Investigación y el Desarrollo en Andrología, Madrid, Spain
| | - Sonia Gabancho
- Fundación para la Investigación y el Desarrollo en Andrología, Madrid, Spain
| | | | - Peter Ney
- Corporate Development, Schwarz Pharma, Monheim, Germany
| | - Iñigo Sáenz de Tejada
- Fundación para la Investigación y el Desarrollo en Andrología, Madrid, Spain
- Departamento de Investigación, Hospital Ramón y Cajal, Madrid, Spain
- Author for correspondence:
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Marlière S, Cracowski JL, Durand T, Chavanon O, Bessard J, Guy A, Stanke-Labesque F, Rossi JC, Bessard G. The 5-series F(2)-isoprostanes possess no vasomotor effects in the rat thoracic aorta, the human internal mammary artery and the human saphenous vein. Br J Pharmacol 2002; 135:1276-80. [PMID: 11877336 PMCID: PMC1573222 DOI: 10.1038/sj.bjp.0704558] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Among the F(2)-isoprostanes, the 15- and the 5-series are currently used as markers of lipid peroxidation in vascular diseases. 15-F(2t)-IsoP (also named iPF(2 alpha)-III) exerts a vasoconstriction in most vessels, whereas no data is available concerning 5-F(2t)-IsoP (also named iPF(2 alpha)-VI), which is more abundant in plasma. 2. The aim of this study was to determine whether 5-F(2t)-IsoP possess any vascular effects on various vessels including the isolated rat thoracic aorta, the human internal mammary artery and the saphenous vein. 3. In organ baths, 5-F(2t)-IsoP and its 5-epimer did not affect the basal tone of any vessel, unlike 15-F(2t)-IsoP. These compounds possessed no antagonist effects on 15-F(2t)-IsoP-induced contractions, No dilator effect was observed in comparison with sodium nitroprusside and acetylcholine on the rat aorta. 4. In conclusion, we show that unlike 15-F(2t)-IsoP, 5-F(2t)-IsoP and its 5-epimer possess no vasomotor effects and as such are unlikely to be involved in the pathogenesis of vascular diseases. Further studies are required to test whether these mediators may have effects on systems not being measured in the current study.
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Affiliation(s)
- Stéphanie Marlière
- Laboratoire de Pharmacologie, LSCPA EA2937, Faculté de Médecine et Centre Hospitalier de Grenoble, France
| | - Jean-Luc Cracowski
- Laboratoire de Pharmacologie, LSCPA EA2937, Faculté de Médecine et Centre Hospitalier de Grenoble, France
- Author for correspondence:
| | - Thierry Durand
- Laboratoire de Chimie Biomoléculaire, UMR CNRS 5074, Faculté de Pharmacie de Montpellier, France
| | - Olivier Chavanon
- Service de chirurgie cardiaque, Centre Hospitalier de Grenoble, France
| | - Janine Bessard
- Laboratoire de Pharmacologie, LSCPA EA2937, Faculté de Médecine et Centre Hospitalier de Grenoble, France
| | - Alexandre Guy
- Laboratoire de Chimie Biomoléculaire, UMR CNRS 5074, Faculté de Pharmacie de Montpellier, France
| | - Françoise Stanke-Labesque
- Laboratoire de Pharmacologie, LSCPA EA2937, Faculté de Médecine et Centre Hospitalier de Grenoble, France
| | - Jean-Claude Rossi
- Laboratoire de Chimie Biomoléculaire, UMR CNRS 5074, Faculté de Pharmacie de Montpellier, France
| | - Germain Bessard
- Laboratoire de Pharmacologie, LSCPA EA2937, Faculté de Médecine et Centre Hospitalier de Grenoble, France
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Janssen LJ. Isoprostanes: an overview and putative roles in pulmonary pathophysiology. Am J Physiol Lung Cell Mol Physiol 2001; 280:L1067-82. [PMID: 11350785 DOI: 10.1152/ajplung.2001.280.6.l1067] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Isoprostanes are produced during peroxidation of membrane lipids by free radicals and reactive oxygen species. Initially, they were recognized as being valuable markers of oxidative stress, and in the past 10 years, dozens of disease states and experimental conditions with diverse etiologies have been shown to be associated with marked increases in urinary, plasma, and tissue levels of isoprostanes. However, they are not just mere markers; they evoke important biological responses on virtually every cell type found within the lung, and these responses exhibit compound-, tissue-, and species-related variations. In fact, the isoprostanes may mediate many of the features of the disease states for which they are used as indicators. In this review, I describe the chemistry, metabolism, and pharmacology of isoprostanes, with a particular emphasis on pulmonary cell types, and the possible roles of isoprostanes in pulmonary pathophysiology.
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Affiliation(s)
- L J Janssen
- Asthma Research Group, Father Sean O'Sullivan Research Center, St. Joseph's Hospital, McMaster University, 50 Charlton Ave. East, Hamilton, Ontario L8N 4A6, Canada.
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8
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Cracowski JL, Devillier P, Durand T, Stanke-Labesque F, Bessard G. Vascular biology of the isoprostanes. J Vasc Res 2001; 38:93-103. [PMID: 11316945 DOI: 10.1159/000051036] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Isoprostanes are a family of compounds produced from polyunsaturated fatty acids via a free-radical-catalysed mechanism. F(2)-isoprostanes are prostaglandin F(2alpha) isomers derived from arachidonic acid. These compounds induce potent vasoconstriction, mediated primarily by TP receptor stimulation, and in some vessels by the release of cyclooxygenase products. This vasoconstriction may be modulated by the endothelium through the release of NO. Potent vasoconstriction is also observed with E(2)-isoprostanes. Experimental and clinical data suggest a role for F(2)-isoprostanes in atherogenesis. These compounds can be detected in free forms in biological fluids as well as esterified in low-density lipoproteins or cell membranes. Their quantification represents a reliable marker of lipid peroxidation. Elevated levels of F(2)-isoprostanes in biological fluids in pathological conditions including atherosclerosis, ischaemia-reperfusion injury, and inflammatory vascular diseases, suggest a relationship between lipid peroxidation and such diseases. F(2)-isoprostanes are currently being investigated as non-invasive quantitative markers to monitor the response to anti-oxidant treatment.
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Affiliation(s)
- J L Cracowski
- Laboratoire de Pharmacologie, LSCPA EA2937, Faculté de Médecine de Grenoble, France.
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Janssen LJ. Isoprostanes: generation, pharmacology, and roles in free-radical-mediated effects in the lung. Pulm Pharmacol Ther 2000; 13:149-55. [PMID: 10930353 DOI: 10.1006/pupt.2000.0244] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isoprostanes are produced during peroxidation of membrane lipids by free radicals and reactive oxygen species, and are currently used as markers of many disease states and experimental conditions in which oxidative stress is a prominent feature. A small number of reports have described the ability of some isoprostanes to evoke important biological effects in smooth muscle and other cell types. However, most of these studies were done using rat tissues, and only two specific isoprostanes - 8-iso-PGE(2)and 8-iso-PGF(2alpha)- were tested. In this review, we describe the generation of isoprostanes during oxidative stress, and their effects on smooth muscle, including our novel findings of their effects on human airway, pulmonary artery and pulmonary vein smooth muscles. Collectively, the data suggest that isoprostanes may not only be markers, but may in fact mediate the effects of free radicals and reactive oxygen species.
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Affiliation(s)
- L J Janssen
- Asthma Research Group, Father Sean O'Sullivan Research Center, Hamilton, Ontario, Canada.
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10
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Awe SO, Opere CA, Harris LC, Uketui AJ, Ohia SE. Effect of isoprostanes on sympathetic neurotransmission in the human isolated iris-ciliary body. Neurochem Res 2000; 25:491-6. [PMID: 10823581 DOI: 10.1023/a:1007560025570] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Isoprostanes (IsoP's) are prostaglandin-like compounds that are derived from free-radical catalyzed peroxidation of arachidonic acid independent of the cyclcooxygenase enzyme. In the present study, we investigated the effect of IsoP's on norepinephrine (NE) release from human isolated iris-ciliary bodies. Isolated human iris-ciliary bodies were prepared for studies of [3H]NE release using the superfusion method. Both 8-iso-prostaglandin F2alpha (F2-IsoP) and the thromboxane (Tx) receptor agonist, U46619 enhanced field-stimulated [3H]NE release from isolated, superfused human iris-ciliary bodies without affecting basal tritium efflux. On the other hand, an equimolar concentration (10 microM) of 8-iso-prostaglandin E2 (E2-IsoP) inhibited evoked [3H]NE overflow. The Tx-receptor antagonist, SQ 29548 blocked the enhancements of electrically-evoked [3H]NE release induced by F2-IsoP and U46619. However, the inhibitory responses elicited by E2-IsoP was not antagonized by SQ 29548. We conclude that IsoP's can produce both excitatory and inhibitory effects on sympathetic neurotransmission in human isolated iris-ciliary bodies. The stimulatory effects of IsoP's on NE release may be mediated by Tx-receptors.
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Affiliation(s)
- S O Awe
- Department of Pharmaceutical and Administrative Sciences, School of Pharmacy and Allied Health Professions, Creighton University, Omaha, NE 68178, USA
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Kromer BM, Tippins JR. The vasoconstrictor effect of 8-epi prostaglandin F2alpha in the hypoxic rat heart. Br J Pharmacol 1999; 126:1171-4. [PMID: 10205005 PMCID: PMC1565897 DOI: 10.1038/sj.bjp.0702433] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. 8-epi prostaglandin (PG) F2alpha, a vasoconstrictor isoprostane, is synthesized under conditions of oxidative stress. This study was undertaken to investigate the vasoconstrictor effect of 8-epi PGF2alpha in the coronary circulation before and after a period of oxidative stress. 2. The effects of the isoprostane 8-epi PGF2alpha and the thromboxane mimetic U46619 were compared in the isolated rat heart perfused in the Langendorff mode at a constant pressure of 80 mmHg. 3. In normal hearts U46619 caused a dose-related reduction in coronary flow (ED50 4.7+/-2.2 nmol). In contrast, 8-epi PGF2alpha had no effect. 4. After reducing perfusion pressure to 20 mmHg for 30 min and reperfusing at 80 mmHg, the dose-response curve to U46619 was unaffected. In contrast, 8-epi PGF2alpha caused a dose-dependent drop in coronary flow (ED50 52.6+/-12.7 nmol), producing a similar maximal reduction to U46619. 5. Similarly, after perfusion with xanthine and xanthine oxidase for either 15 or 30 min there was little change in the response to U46619 in comparison to control hearts. In contrast, 8-epi PGF2alpha caused a reduction in coronary flow similar to that produced by U46619, the magnitude of the response being related to the length of xanthine/xanthine oxidase perfusion. 6. Responses to both U46619 and 8-epi PGF2alpha after xanthine/xanthine oxidase perfusion were blocked by the selective thromboxane receptor antagonist SQ29548 10(-7) M. 7. These results show that oxidative stress in the isolated perfused rat heart reveals a potent vasoconstrictor effect of the isoprostane 8-epi PGF2alpha by an action on the thromboxane receptor. 8. The data also suggest that, since 8-epi PGF2alpha is a partial agonist at the thromboxane receptor, thromboxane receptor reserve is increased by oxidative stress.
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Affiliation(s)
- Brendan M Kromer
- Biochemistry Department, Imperial College of Science, Technology & Medicine, London SW7 2AY, U.K
| | - John R Tippins
- Biochemistry Department, Imperial College of Science, Technology & Medicine, London SW7 2AY, U.K
- Author for correspondence:
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