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Flavonoids and Their Metabolites: Prevention in Cardiovascular Diseases and Diabetes. Diseases 2017; 5:diseases5030019. [PMID: 32962323 PMCID: PMC5622335 DOI: 10.3390/diseases5030019] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/01/2017] [Accepted: 09/03/2017] [Indexed: 12/12/2022] Open
Abstract
The occurrence of atherosclerosis and diabetes is expanding rapidly worldwide. These two metabolic disorders often co-occur, and are part of what is often referred to as the metabolic syndrome. In order to determine future therapies, we propose that molecular mechanisms should be investigated. Once the aetiology of the metabolic syndrome is clear, a nutritional intervention should be assessed. Here we focus on the protective effects of some dietary flavonoids, and their metabolites. Further studies may also pave the way for development of novel drug candidates.
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Kleniewska P, Kowalczyk A, Ciesla W, Goraca A. Estimation of Some Oxidative Stress Parameters and Blood Pressure After Administration of Endothelin-1 (ET-1) in Rats. Cell Biochem Biophys 2016; 71:1483-9. [PMID: 25391890 DOI: 10.1007/s12013-014-0371-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of the study was to investigate changes in the plasma antioxidative activity and in lipid peroxidation after administration of endothelin-1 (ET-1) and endothelin receptor blockers and additionally, to estimate blood pressure. The study was performed on male Wistar rats (n = 6 per group) divided into 4 groups which received: (1) saline, (2) endothelin-1 (ET-1) (3 μg/kg b.w.) + saline, (3) BQ123 (1 mg/kg) + ET-1 (3 μg/kg), and (4) BQ788 (3 mg/kg) + ET-1 (3 μg/kg b.w.). The endothelin receptor antagonist was injected intravenously 30 min before ET-1 administration. Blood pressure was monitored, and the blood was collected before the saline or ET-1 administration as well as 60 and 300 min after their administration. The antioxidative properties were examined by FRAP method (ferric reducing ability of plasma), and the concentration of lipid peroxidation products was examined by the reaction with thiobarbituric acid (TBARS). It was estimated that intravenous administration of endothelin receptor blocker ETA increases plasma antioxidative properties (p < 0.01) and parallelly decreases the process of lipid peroxidation (p < 0.05 vs. ET-1) and blood pressure (p < 0.05).
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Affiliation(s)
- Paulina Kleniewska
- Experimental and Clinical Physiology, Department of Cardiovascular Physiology, Medical University of Lodz, ul. Mazowiecka 6/8, 92-215, Lodz, Poland.
| | - Agata Kowalczyk
- Experimental and Clinical Physiology, Department of Cardiovascular Physiology, Medical University of Lodz, ul. Mazowiecka 6/8, 92-215, Lodz, Poland
| | - Wlodzimierz Ciesla
- Experimental and Clinical Physiology, Department of Cardiovascular Physiology, Medical University of Lodz, ul. Mazowiecka 6/8, 92-215, Lodz, Poland
| | - Anna Goraca
- Experimental and Clinical Physiology, Department of Cardiovascular Physiology, Medical University of Lodz, ul. Mazowiecka 6/8, 92-215, Lodz, Poland
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Abstract
SIGNIFICANCE Oxygen plays a key role in cellular metabolism and function. Oxygen delivery to cells is crucial, and a lack of oxygen such as that which occurs during myocardial infarction can be lethal. Cells should, therefore, be able to respond to changes in oxygen tension. RECENT ADVANCES Since the first studies examining the acute cellular effect of hypoxia on activation of transmitter release from glomus or type I chemoreceptor cells, it is now known that virtually all cells are able to respond to changes in oxygen tension. CRITICAL ISSUES Despite advances made in characterizing hypoxic responses, the identity of the "oxygen sensor" remains debated. Recently, more evidence has evolved as to how cardiac myocytes sense acute changes in oxygen. This review will examine the available evidence in support of acute oxygen-sensing mechanisms providing a brief historical perspective and then more detailed insights into the heart and the role of cardiac ion channels in hypoxic responses. FUTURE DIRECTIONS A further understanding of these cellular processes should result in interventions that assist in preventing the deleterious effects of acute changes in oxygen tension such as alterations in contractile function and cardiac arrhythmia.
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Affiliation(s)
- Livia C Hool
- School of Anatomy, Physiology, and Human Biology, The University of Western Australia , Crawley, Australia
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Wojtera E, Konior A, Fedoryszak-Kuśka N, Beręsewicz A. Obligatory role of intraluminal O2- in acute endothelin-1 and angiotensin II signaling to mediate endothelial dysfunction and MAPK activation in guinea-pig hearts. Int J Mol Sci 2014; 15:19417-43. [PMID: 25350109 PMCID: PMC4264120 DOI: 10.3390/ijms151119417] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/30/2014] [Accepted: 10/08/2014] [Indexed: 01/07/2023] Open
Abstract
We hypothesized that, due to a cross-talk between cytoplasmic O2--sources and intraluminally expressed xanthine oxidase (XO), intraluminal O2- is instrumental in mediating intraluminal (endothelial dysfunction) and cytosolic (p38 and ERK1/2 MAPKs phosphorylation) manifestations of vascular oxidative stress induced by endothelin-1 (ET-1) and angiotensin II (AT-II). Isolated guinea-pig hearts were subjected to 10-min agonist perfusion causing a burst of an intraluminal O2-. ET-1 antagonist, tezosentan, attenuated AT-II-mediated O2-, indicating its partial ET-1 mediation. ET-1 and Ang-T (AT-II+tezosentan) triggered intraluminal O2-, endothelial dysfunction, MAPKs and p47phox phosphorylation, and NADPH oxidase (Nox) and XO activation. These effects were: (i) prevented by blocking PKC (chelerythrine), Nox (apocynin), mitochondrial ATP-dependent K+ channel (5-HD), complex II (TTFA), and XO (allopurinol); (ii) mimicked by the activation of Nox (NADH); and mitochondria (diazoxide, 3-NPA) and (iii) the effects by NADH were prevented by 5-HD, TTFA and chelerythrine, and those by diazoxide and 3-NPA by apocynin and chelerythrine, suggesting that the agonists coactivate Nox and mitochondria, which further amplify their activity via PKC. The effects by ET-1, Ang-T, NADH, diazoxide, and 3-NPA were opposed by blocking intraluminal O2- (SOD) and XO, and were mimicked by XO activation (hypoxanthine). Apocynin, TTFA, chelerythrine, and SOD opposed the effects by hypoxanthine. In conclusion, oxidative stress by agonists involves cellular inside-out and outside-in signaling in which Nox-mitochondria-PKC system and XO mutually maintain their activities via the intraluminal O2-.
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Affiliation(s)
- Emilia Wojtera
- Department of Clinical Physiology, Postgraduate Medical School, Warsaw 01-813, Poland.
| | - Anna Konior
- Department of Clinical Physiology, Postgraduate Medical School, Warsaw 01-813, Poland.
| | | | - Andrzej Beręsewicz
- Department of Clinical Physiology, Postgraduate Medical School, Warsaw 01-813, Poland.
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Turkili B, Kurcer Z, Dengiz GO, Kandemir NO, Mungan G, Ozacmak VH, Banoglu ZN. Role of angiotensin and endothelin in testicular ischemia reperfusion injury. Int J Urol 2011; 19:257-63. [PMID: 22168394 DOI: 10.1111/j.1442-2042.2011.02924.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To determine whether angiotensin and endothelin have any role in testicular ischemia reperfusion injury by investigating the effects of the angiotensin converting enzyme inhibitor enalapril, selective non-peptide angiotensin-II type I blocker losartan and dual endothelin receptor blocker bosentan. METHODS Rats were anesthetized with thiopental sodium (50 mg/kg i.p.) before the operation. The left testicular artery and vein of rats were occluded for 1 h; before the bilateral orchiectomy, the organ was allowed to reperfuse for 3 h or 24 h. Enalapril (20 mg/kg i.p.), losartan (30 mg/kg i.p.), bosentan (10 mg/kg i.p.) or vehicle (saline) were given 30 min before reperfusion. Malondialdehyde level was measured in testicular tissue after 3 h of reperfusion. Histological examination was carried out after 24 h of reperfusion. RESULTS Ischemia reperfusion caused a significant increase in malondialdehyde level of ipsilateral testis, and histopathological injury in both ipsilateral and contralateral testes. Enalapril, losartan and bosentan treatments prevented the ischemia reperfusion-induced augmentation in malondialdehyde levels. Only bosentan treatment ameloriated ischemia reperfusion-induced histopathological alterations. CONCLUSIONS Endothelin might play a more important role in pathogenesis of testicular ischemia reperfusion injury when compared with angiotensin.
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Affiliation(s)
- Burak Turkili
- Department of Pharmacology, Institute of Health Sciences, Zonguldak Karaelmas University, Zonguldak, Turkey
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de Beer VJ, de Graaff HJD, Hoekstra M, Duncker DJ, Merkus D. Integrated control of pulmonary vascular tone by endothelin and angiotensin II in exercising swine depends on gender. Am J Physiol Heart Circ Physiol 2010; 298:H1976-85. [PMID: 20348226 DOI: 10.1152/ajpheart.00459.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The lungs are now recognized as an active metabolic organ that is a major determinant of the plasma concentrations of the vasoconstrictors endothelin (ET) and ANG II. Several studies have suggested a complex interaction between ET and ANG II in the systemic and coronary vascular beds that is different at rest and during exercise. To date, the interaction between these vasoconstrictor peptides has barely been investigated in relation to the pulmonary vascular bed. Consequently, we investigated the integrated control of pulmonary vasomotor tone by ET and ANG II in 24 chronically instrumented swine (15 female and 9 male) at rest and during graded treadmill exercise. In the systemic circulation, ANG II type 1 (AT(1)) receptor blockade with irbesartan and mixed ET(A)/ET(B) blockade with tezosentan each produced vasodilation. The systemic vasodilator effect of ET(A)/ET(B) blockade was enhanced after AT(1) blockade in female swine, whereas a trend toward an increase was observed in male swine. In the pulmonary circulation, AT(1) receptor blockade had no effect on pulmonary vascular tone in male swine, whereas it resulted in an unexpected increase in pulmonary vasomotor tone in female swine. ET(A)/ET(B) receptor blockade did not result in a decrease in pulmonary vasomotor tone at rest but produced a decrease in vasomotor tone during exercise in both genders. This pulmonary vasodilation by ET(A)/ET(B) receptor blockade was enhanced after prior AT(1) blockade in female swine but not in male swine. In conclusion, in both the systemic and pulmonary circulation of female swine, ANG II inhibits the vasoconstrictor influence of ET. This interaction is gender specific. The observation that plasma ET levels were not altered by AT(1) blockade in either gender suggests that the interaction between these vasoconstrictors occurs locally in the vasculature.
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Affiliation(s)
- Vincent J de Beer
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Cardiovascular Research School COEUR, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
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Watts SW. Endothelin receptors: what's new and what do we need to know? Am J Physiol Regul Integr Comp Physiol 2009; 298:R254-60. [PMID: 19907001 DOI: 10.1152/ajpregu.00584.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Receptors are at the heart of how a molecule transmits a signal to a cell. Two receptor classes for endothelin (ET) are recognized, the ET(A) and ET(B) receptors. Intriguing questions have arisen in the field of ET receptor pharmacology, physiology, and function. For example, a host of pharmacological studies support the interaction of the ET(A) and ET(B) receptor in tissues (veins, arteries, bronchus, arterioles, esophagus), but yet few have been able to demonstrate direct ET(A)/ET(B) receptor interaction. Have we modeled this interaction wrong? Do we have a truly selective ET(A) receptor agonist such that we could selectively stimulate this important receptor? What can we learn from the recent phylogenic studies of the ET receptor family? Have we adequately addressed the number of biological molecules with which ET can interact to exert a biological effect? Recent mass spectrometry studies in our laboratory suggest that ET-1 interacts with other hereto unrecognized proteins. Biased ligands (ligands at the same receptor that elicit distinct signaling responses) have been discovered for other receptors. Do these exist for ET receptors and can we take advantage of this possibility in drug design? These and other questions will be posed in this minireview on topics on ET receptors.
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Affiliation(s)
- Stephanie W Watts
- Dept. of Pharmacology and Toxicology, B445 Life Sciences Bldg., East Lansing, MI 48824-1317, USA.
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Zhou J, Zhu Y, Cheng M, Dinesh D, Thorne T, Poh KK, Liu D, Botros C, Tang YL, Reisdorph N, Kishore R, Losordo DW, Qin G. Regulation of vascular contractility and blood pressure by the E2F2 transcription factor. Circulation 2009; 120:1213-21. [PMID: 19752322 DOI: 10.1161/circulationaha.109.859207] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Recent studies have identified a polymorphism in the endothelin-converting enzyme (ECE)-1b promoter (-338C/A) that is strongly associated with hypertension in women. The polymorphism is located in a consensus binding sequence for the E2F family of transcription factors. E2F proteins are crucially involved in cell-cycle regulation, but their roles in cardiovascular function are poorly understood. Here, we investigated the potential role of E2F2 in blood pressure regulation. METHODS AND RESULTS Tail-cuff measurements of systolic and diastolic blood pressures were significantly higher in E2F2-null (E2F2(-/-)) mice than in their wild-type littermates, and in ex vivo ring assays, aortas from the E2F2(-/-) mice exhibited significantly greater contractility in response to big endothelin-1. Big endothelin-1 is activated by ECE-1, and mRNA levels of ECE-1b, the repressive ECE-1 isoform, were significantly lower in E2F2(-/-) mice than in wild-type mice. In endothelial cells, chromatin immunoprecipitation assays confirmed that E2F2 binds the ECE-1b promoter, and promoter-reporter assays indicated that E2F2 activates ECE-1b transcription. Furthermore, loss or downregulation of E2F2 led to a decline in ECE-1b levels, to higher levels of the membranous ECE-1 isoforms (ie, ECE-1a, -1c, and -1d), and to deregulated ECE-1 activity. Finally, Sam68 coimmunoprecipitated with E2F2, occupied the ECE-1b promoter (chromatin immunoprecipitation), and repressed E2F2-mediated ECE-1b promoter activity (promoter-reporter assays). CONCLUSIONS Our results identify a cell-cycle-independent mechanism by which E2F2 regulates endothelial function, arterial contractility, and blood pressure.
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Affiliation(s)
- Junlan Zhou
- Assistant Professor, Feinberg Cardiovascular Research Institute, Northwestern University, 303 E Chicago Ave, Tarry 14-751, Chicago, IL 60611, USA
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Salcedo A, Fernández N, García Villalón AL, Monge L, Narváez Sánchez R, Diéguez G. Role of angiotensin II in the response to endothelin-1 of goat cerebral arteries after ischemia-reperfusion. Vascul Pharmacol 2009; 50:160-5. [PMID: 19135174 DOI: 10.1016/j.vph.2008.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 10/30/2008] [Accepted: 12/05/2008] [Indexed: 10/21/2022]
Abstract
As angiotensin II may underlie the deleterious effects of some vascular diseases, we have examined the role of this peptide on the cerbrovascular endothelin-1 action after ischemia-reperfusion. In anesthetized goats, 1 hour-occlusion followed by 1 hour-reperfusion of the left middle cerebral artery (MCA) was induced, and then segments 3-mm in length from branches of the right MCA (control) and the left MCA (ischemic) were obtained for isometric tension recording. Endothelin-1 (10(-11)-10(-7) M) produced a contraction that was higher in ischemic than in control arteries, and in control but not in ischemic arteries this contraction was potentiated by angiotensin II (10(-7) M). Losartan (3 x 10(-6) M), antagonist of AT1 receptors, did not affect the response to endothelin-1 in control arteries, but reduced it both in ischemic arteries and angiotensin II-treated control arteries. PD123,319 (3 x 10(-6) M), antagonist of AT2 receptors, or the inhibitor of nitric oxide synthesis L-NAME (10(-4) M) did not alter the arterial effects of endothelin-1. Therefore, angiotensin II may potentiate the constriction to endothelin-1 in normal cerebral arteries by activating AT1 receptors. The observed cerebrovascular increased response to endothelin-1 after ischemia-reperfusion might be related in part to activation of AT1 receptors under this condition.
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Affiliation(s)
- Adely Salcedo
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma, Arzobispo Morcillo, 4, 28029 Madrid, Spain
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Schlüter KD, Wenzel S. Angiotensin II: a hormone involved in and contributing to pro-hypertrophic cardiac networks and target of anti-hypertrophic cross-talks. Pharmacol Ther 2008; 119:311-25. [PMID: 18619489 DOI: 10.1016/j.pharmthera.2008.05.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 05/30/2008] [Indexed: 12/23/2022]
Abstract
Angiotensin II (Ang II) plays a major role in the progression of myocardial hypertrophy to heart failure. Inhibiting the angiotensin converting enzyme (ACE) or blockade of the corresponding Ang II receptors is used extensively in clinical practice, but there is scope for refinement of this mode of therapy. This review summarizes the current understanding of the direct effects of Ang II on cardiomyocytes and then focus particularly on interaction of components of the renin-angiotensin system with other hormones and cytokines. New findings described in approximately 400 papers identified in the PubMed database and published during the 2.5 years are discussed in the context of previous relevant literature. The cardiac action of Ang II is influenced by the activity of different isoforms of ACE leading to different amounts of Ang II by comparison with other angiotensinogen-derived peptides. The effect of Ang II is mediated by at least two different AT receptors that are differentially expressed in cardiomyocytes from neonatal, adult and failing hearts. The intracellular effects of Ang II are influenced by nitric oxide (NO)/cGMP-dependent cross talk and are mediated by the release of autocrine factors, such as transforming growth factor (TGF)-beta1 and interleukin (IL)-6. Besides interactions with cytokines, Ang II is involved in systemic networks including aldosterone, parathyroid hormone and adrenomedullin, which have their own effects on cardiomyocytes that modify, amplify or antagonize the primary effect of Ang II. Finally, hyperinsulemia and hyperglycaemia influence Ang II-dependent processes in diabetes and its cardiac sequelae.
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Affiliation(s)
- K-D Schlüter
- Physiologisches Institut, Justus-Liebig-Universität Giessen, Germany.
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de Beer VJ, Sorop O, Pijnappels DA, Dekkers DH, Boomsma F, Lamers JMJ, Duncker DJ, Merkus D. Integrative control of coronary resistance vessel tone by endothelin and angiotensin II is altered in swine with a recent myocardial infarction. Am J Physiol Heart Circ Physiol 2008; 294:H2069-77. [DOI: 10.1152/ajpheart.01163.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several studies have indicated an interaction between the renin-angiotensin (ANG II) system and endothelin (ET) in the regulation of vascular tone. Previously, we have shown that both ET and ANG II exert a vasoconstrictor influence on the coronary resistance vessels of awake normal swine. Here, we investigated whether the interaction between ANG II and ET exists in the control of coronary resistance vessel tone at rest and during exercise using single and combined blockade of angiotensin type 1 (AT1) and ETA/ETB receptors. Since both circulating ANG II and ET levels are increased after myocardial infarction (MI), we investigated if the interaction between these systems is altered after MI. In awake healthy swine, coronary vasodilation in response to ETA/ETB receptor blockade in the presence of AT1 blockade was similar to vasodilation produced by ETA/ETB blockade under control conditions. In awake swine with a 2- to 3-wk-old MI, coronary vasodilator responses to individual AT1 and ETA/ETB receptor blockade were virtually abolished, despite similar coronary arteriolar AT1 and ETA receptor expression compared with normal swine. Unexpectedly, in the presence of AT1 blockade (which had no effect on circulating ET levels), ETA/ETB receptor blockade elicited a coronary vasodilator response. These findings suggest that in normal healthy swine the two vasoconstrictor systems contribute to coronary resistance vessel control in a linear additive manner, i.e., with negligible cross-talk. In contrast, in the remodeled myocardium, cross-talk between ANG II and ET emerges, resulting in nonlinear redundant control of coronary resistance vessel tone.
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Abstract
Important roles for reactive oxygen species (ROS) in physiology and pathophysiology have been increasingly recognized. Under normal conditions, ROS serve as signaling molecules in the regulation of cellular functions. However, enhanced ROS production as a result of the activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase contributes significantly to the pathogeneses of vascular diseases. Although it has become evident that increased ROS is associated with erectile dysfunction (ED), the sources of ROS in the penis remain largely unknown. In recent years, emergent evidence suggests the possible role of NADPH oxidase in inducing ED. In this review, we examine the relationship between ROS and ED in different disease models and discuss the current evidence basis for NADPH oxidase-derived ROS in ED.
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Affiliation(s)
- Liming Jin
- Department of Internal Medicine, University of California, Davis, CA 95616, USA.
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Just A, Whitten CL, Arendshorst WJ. Reactive oxygen species participate in acute renal vasoconstrictor responses induced by ETAand ETBreceptors. Am J Physiol Renal Physiol 2008; 294:F719-28. [DOI: 10.1152/ajprenal.00506.2007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Reactive oxygen species (ROS) play important roles in renal vasoconstrictor responses to acute and chronic stimulation by angiotensin II and norepinephrine, as well as in long-term effects of endothelin-1 (ET-1). Little is known about participation of ROS in acute vasoconstriction produced by ET-1. We tested the influence of NAD(P)H oxidase inhibition by apocynin [4 mg·kg−1·min−1, infused into the renal artery (ira)] on ETAand ETBreceptor signaling in the renal microcirculation. Both receptors were stimulated by ET-1, ETAreceptors by ET-1 during ETBantagonist BQ-788, and ETBby ETBagonist sarafotoxin 6C. ET-1 (1.5 pmol injected ira) reduced renal blood flow (RBF) 17 ± 4%. Apocynin raised baseline RBF (+10 ± 1%, P < 0.001) and attenuated the ET-1 response to 10 ± 2%, i.e., 35 ± 9% inhibition ( P < 0.05). Apocynin reduced ETA-induced vasoconstriction by 42 ± 12% ( P < 0.05) and that of ETBstimulation by 50 ± 8% ( P < 0.001). During nitric oxide (NO) synthase inhibition ( Nω-nitro-l-arginine methyl ester), apocynin blunted ETA-mediated vasoconstriction by 60 ± 8% ( P < 0.01), whereas its effect on the ETBresponse (by 87 ± 8%, P < 0.001) was even larger without than with NO present ( P < 0.05). The cell-permeable superoxide dismutase mimetic tempol (5 mg·kg−1·min−1ira), which reduces O2−and may elevate H2O2, attenuated ET-1 responses similar to apocynin (by 38 ± 6%, P < 0.01). We conclude that ROS, O2−rather than H2O2, contribute substantially to acute renal vasoconstriction elicited by both ETAand ETBreceptors and to basal renal vasomotor tone in vivo. This physiological constrictor action of ROS does not depend on scavenging of NO. In contrast, scavenging of O2−by NO seems to be more important during ETBstimulation.
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Quercetin inhibits vascular superoxide production induced by endothelin-1: Role of NADPH oxidase, uncoupled eNOS and PKC. Atherosclerosis 2008; 202:58-67. [PMID: 18436224 DOI: 10.1016/j.atherosclerosis.2008.03.007] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 02/13/2008] [Accepted: 03/10/2008] [Indexed: 12/29/2022]
Abstract
Chronic administration of the most abundant dietary flavonoid quercetin exerts antihypertensive effects and improves endothelial function. We have investigated the effects of quercetin and its methylated metabolite isorhamnetin (1-10microM) on endothelial dysfunction and superoxide (O(2*)(-)) production induced by endothelin-1 (ET-1, 10nM). ET-1 increased the contractile response induced by phenylephrine and reduced the relaxant responses to acetylcholine in phenylephrine contracted intact aorta, and these effects were prevented by co-incubation with quercetin, isorhamnetin or chelerythrine (protein kinase C (PKC) inhibitor). This endothelial dysfunction was also improved by superoxide dismutase (SOD), apocynin (NADPH oxidase inhibitor) and sepiapterin (tetrahydrobiopterin synthesis substrate). Furthermore, ET-1 increased intracellular O(2*)(-) production in all layers of the vessel, protein expression of NADPH oxidase subunit p47(phox) without affecting p22(phox) expression and lucigenin-enhanced chemiluminescence signal stimulated by calcium ionophore A23187. All these changes were prevented by both quercetin and isorhamnetin. Moreover, apocynin, endothelium denudation and N(G)-nitro-l-arginine methylester (l-NAME, nitric oxide synthase inhibitor) suppressed the ET-1-induced increase in A23187-stimulated O(2*)(-) generation. Moreover, quercetin but not isorhamnetin, inhibited the increased PKC activity induced by ET-1. Taken together these results indicate that ET-1-induced NADPH oxidase up-regulation and eNOS uncoupling via PKC leading to endothelial dysfunction and these effects were prevented by quercetin and isorhamnetin.
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