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Cheung A, Streijger F, So K, Okon EB, Manouchehri N, Shortt K, Kim KT, Keung MSM, Chan RM, Fong A, Sun J, Griesdale DE, Sehkon MS, Kwon BK. Relationship between Early Vasopressor Administration and Spinal Cord Hemorrhage in a Porcine Model of Acute Traumatic Spinal Cord Injury. J Neurotrauma 2020; 37:1696-1707. [PMID: 32233727 DOI: 10.1089/neu.2019.6781] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Current practice guidelines for acute spinal cord injury (SCI) recommend augmenting mean arterial blood pressure (MAP) for the first 7 days post-injury. After SCI, the cord may be compressed by the bone/ligaments of the spinal column, limiting regional spinal cord blood flow. Following surgical decompression, blood flow may be restored, and can potentially promote a "reperfusion" injury. The effects of MAP augmentation on the injured cord during the compressed and decompressed conditions have not been previously characterized. Here, we used our porcine model of SCI to examine the impact of MAP augmentation on blood flow, oxygenation, hydrostatic pressure, metabolism, and intraparenchymal (IP) hemorrhage within the compressed and then subsequently decompressed spinal cord. Yucatan mini-pigs underwent a T10 contusion injury followed by 2 h of sustained compression. MAP augmentation of ∼20 mm Hg was achieved with norepinephrine (NE). Animals received MAP augmentation either during the period of cord compression (CP), after decompression (DCP), or during both periods (CP-DCP). Probes to monitor spinal cord blood flow (SCBF), oxygenation, pressure, and metabolic responses were inserted into the cord parenchyma adjacent to the injury site to measure these responses. The cord was harvested for histological evaluation. MAP augmentation increased SCBF and oxygenation in all groups. In the CP-DCP group, spinal cord pressure steadily increased and histological analysis showed significantly increased hemorrhage in the spinal cord at and near the injury site. MAP augmentation with vasopressors may improve blood flow and reduce ischemia in the injured cord but may also induce undesirable increases in IP pressure and hemorrhage.
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Affiliation(s)
- Amanda Cheung
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Femke Streijger
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Kitty So
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Elena B Okon
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Neda Manouchehri
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Katelyn Shortt
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Kyoung-Tae Kim
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada.,Department of Neurosurgery, Kyungpook National University Hospital, Kyungpook National University, Daegu, South Korea
| | - Martin Sheung Man Keung
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Ryan M Chan
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Allan Fong
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jenny Sun
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Donald E Griesdale
- Department of Anesthesiology, Division of Critical Care Medicine, Vancouver General Hospital, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Mypinder S Sehkon
- Department of Medicine, Division of Critical Care Medicine, Vancouver General Hospital, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian K Kwon
- International Collaboration on Repair Discoveries, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada.,Vancouver Spine Surgery Institute, Department of Orthopedics, The University of British Columbia, Vancouver, British Columbia, Canada
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Estevez AY, Ganesana M, Trentini JF, Olson JE, Li G, Boateng YO, Lipps JM, Yablonski SER, Donnelly WT, Leiter JC, Erlichman JS. Antioxidant Enzyme-Mimetic Activity and Neuroprotective Effects of Cerium Oxide Nanoparticles Stabilized with Various Ratios of Citric Acid and EDTA. Biomolecules 2019; 9:E562. [PMID: 31623336 PMCID: PMC6843313 DOI: 10.3390/biom9100562] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/25/2019] [Accepted: 09/26/2019] [Indexed: 12/11/2022] Open
Abstract
Cerium oxide (CeO2) nanoparticles (CeNPs) are potent antioxidants that are being explored as potential therapies for diseases in which oxidative stress plays an important pathological role. However, both beneficial and toxic effects of CeNPs have been reported, and the method of synthesis as well as physico-chemical, biological, and environmental factors can impact the ultimate biological effects of CeNPs. In the present study, we explored the effect of different ratios of citric acid (CA) and EDTA (CA/EDTA), which are used as stabilizers during synthesis of CeNPs, on the antioxidant enzyme-mimetic and biological activity of the CeNPs. We separated the CeNPs into supernatant and pellet fractions and used commercially available enzymatic assays to measure the catalase-, superoxide dismutase (SOD)-, and oxidase-mimetic activity of each fraction. We tested the effects of these CeNPs in a mouse hippocampal brain slice model of ischemia to induce oxidative stress where the fluorescence indicator SYTOX green was used to assess cell death. Our results demonstrate that CeNPs stabilized with various ratios of CA/EDTA display different enzyme-mimetic activities. CeNPs with intermediate CA/EDTA stabilization ratios demonstrated greater neuroprotection in ischemic mouse brain slices, and the neuroprotective activity resides in the pellet fraction of the CeNPs. The neuroprotective effects of CeNPs stabilized with equal proportions of CA/EDTA (50/50) were also demonstrated in two other models of ischemia/reperfusion in mice and rats. Thus, CeNPs merit further development as a neuroprotective therapy for use in diseases associated with oxidative stress in the nervous system.
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Affiliation(s)
- Ana Y Estevez
- Biology Department, St. Lawrence University, Canton, NY 13617, USA.
- Psychology Department, St. Lawrence University, Canton, NY 13617, USA.
| | - Mallikarjunarao Ganesana
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
| | - John F Trentini
- Department of Emergency Medicine, Wright State University, Boonshoft School of Medicine, Dayton, OH 45435, USA.
| | - James E Olson
- Department of Emergency Medicine, Wright State University, Boonshoft School of Medicine, Dayton, OH 45435, USA.
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Boonshoft School of Medicine, Dayton, OH 45435, USA.
| | - Guangze Li
- Department of Emergency Medicine, Wright State University, Boonshoft School of Medicine, Dayton, OH 45435, USA.
| | - Yvonne O Boateng
- Biology Department, St. Lawrence University, Canton, NY 13617, USA.
| | - Jennifer M Lipps
- Biology Department, St. Lawrence University, Canton, NY 13617, USA.
| | | | - William T Donnelly
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
| | - James C Leiter
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
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Scicchitano P, Cortese F, Gesualdo M, De Palo M, Massari F, Giordano P, Ciccone MM. The role of endothelial dysfunction and oxidative stress in cerebrovascular diseases. Free Radic Res 2019; 53:579-595. [PMID: 31106620 DOI: 10.1080/10715762.2019.1620939] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Pietro Scicchitano
- Department of Cardiology, Hospital “F. Perinei”, Altamura, Italy
- Section of Cardiovascular Diseases, Department of Emergency and Organ Transplantation, School of Medicine, University of Bari, Bari, Italy
| | - Francesca Cortese
- Section of Cardiovascular Diseases, Department of Emergency and Organ Transplantation, School of Medicine, University of Bari, Bari, Italy
| | | | - Micaela De Palo
- Department of Cardiac Surgery, Mater Dei Hospital, Bari, Italy
| | | | - Paola Giordano
- Department of Biomedical Sciences and Human Oncology – Paediatric Unit, Policlinico Hospital, Bari, Italy
| | - Marco Matteo Ciccone
- Section of Cardiovascular Diseases, Department of Emergency and Organ Transplantation, School of Medicine, University of Bari, Bari, Italy
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Cellular and Oxidative Mechanisms Associated with Interleukin-6 Signaling in the Vasculature. Int J Mol Sci 2017; 18:ijms18122563. [PMID: 29186034 PMCID: PMC5751166 DOI: 10.3390/ijms18122563] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 11/17/2017] [Accepted: 11/19/2017] [Indexed: 02/07/2023] Open
Abstract
Reactive oxygen species, particularly superoxide, promote endothelial dysfunction and alterations in vascular structure. It is increasingly recognized that inflammatory cytokines, such as interleukin-6 (IL-6), contribute to endothelial dysfunction and vascular hypertrophy and fibrosis. IL-6 is increased in a number of cardiovascular diseases, including hypertension. IL-6 is also associated with a higher incidence of future cardiovascular events and all-cause mortality. Both immune and vascular cells produce IL-6 in response to a number of stimuli, such as angiotensin II. The vasculature is responsive to IL-6 produced from vascular and non-vascular sources via classical IL-6 signaling involving a membrane-bound IL-6 receptor (IL-6R) and membrane-bound gp130 via Jak/STAT as well as SHP2-dependent signaling pathways. IL-6 signaling is unique because it can also occur via a soluble IL-6 receptor (sIL-6R) which allows for IL-6 signaling in tissues that do not normally express IL-6R through a process referred to as IL-6 trans-signaling. IL-6 signaling mediates a vast array of effects in the vascular wall, including endothelial activation, vascular permeability, immune cell recruitment, endothelial dysfunction, as well as vascular hypertrophy and fibrosis. Many of the effects of IL-6 on vascular function and structure are representative of loss or reductions in nitric oxide (NO) bioavailability. IL-6 has direct effects on endothelial nitric oxide synthase activity and expression as well as increasing vascular superoxide, which rapidly inactivates NO thereby limiting NO bioavailability. The goal of this review is to highlight both the cellular and oxidative mechanisms associated with IL-6-signaling in the vascular wall in general, in hypertension, and in response to angiotensin II.
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Pal S, Meininger CJ, Gashev AA. Aged Lymphatic Vessels and Mast Cells in Perilymphatic Tissues. Int J Mol Sci 2017; 18:E965. [PMID: 28467354 PMCID: PMC5454878 DOI: 10.3390/ijms18050965] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 04/09/2017] [Accepted: 04/26/2017] [Indexed: 12/13/2022] Open
Abstract
This review provides a comprehensive summary of research on aging-associated alterations in lymphatic vessels and mast cells in perilymphatic tissues. Aging alters structure (by increasing the size of zones with low muscle cell investiture), ultrastructure (through loss of the glycocalyx), and proteome composition with a concomitant increase in permeability of aged lymphatic vessels. The contractile function of aged lymphatic vessels is depleted with the abolished role of nitric oxide and an increased role of lymphatic-born histamine in flow-dependent regulation of lymphatic phasic contractions and tone. In addition, aging induces oxidative stress in lymphatic vessels and facilitates the spread of pathogens from these vessels into perilymphatic tissues. Aging causes the basal activation of perilymphatic mast cells, which, in turn, restricts recruitment/activation of immune cells in perilymphatic tissues. This aging-associated basal activation of mast cells limits proper functioning of the mast cell/histamine/NF-κB axis that is essential for the regulation of lymphatic vessel transport and barrier functions as well as for both the interaction and trafficking of immune cells near and within lymphatic collecting vessels. Cumulatively, these changes play important roles in the pathogenesis of alterations in inflammation and immunity associated with aging.
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Affiliation(s)
- Sarit Pal
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX 76504, USA.
| | - Cynthia J Meininger
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX 76504, USA.
| | - Anatoliy A Gashev
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX 76504, USA.
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SOD1 Overexpression Preserves Baroreflex Control of Heart Rate with an Increase of Aortic Depressor Nerve Function. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:3686829. [PMID: 26823951 PMCID: PMC4707341 DOI: 10.1155/2016/3686829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 10/01/2015] [Indexed: 02/07/2023]
Abstract
Overproduction of reactive oxygen species (ROS), such as the superoxide radical (O2∙−), is associated with diseases which compromise cardiac autonomic function. Overexpression of SOD1 may offer protection against ROS damage to the cardiac autonomic nervous system, but reductions of O2∙− may interfere with normal cellular functions. We have selected the C57B6SJL-Tg (SOD1)2 Gur/J mouse as a model to determine whether SOD1 overexpression alters cardiac autonomic function, as measured by baroreflex sensitivity (BRS) and aortic depressor nerve (ADN) recordings, as well as evaluation of baseline heart rate (HR) and mean arterial pressure (MAP). Under isoflurane anesthesia, C57 wild-type and SOD1 mice were catheterized with an arterial pressure transducer and measurements of HR and MAP were taken. After establishing a baseline, hypotension and hypertension were induced by injection of sodium nitroprusside (SNP) and phenylephrine (PE), respectively, and ΔHR versus ΔMAP were recorded as a measure of baroreflex sensitivity (BRS). SNP and PE treatment were administered sequentially after a recovery period to measure arterial baroreceptor activation by recording aortic depressor nerve activity. Our findings show that overexpression of SOD1 in C57B6SJL-Tg (SOD1)2 Gur/J mouse preserved the normal HR, MAP, and BRS but enhanced aortic depressor nerve function.
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Hu C, Lu KT, Mukohda M, Davis DR, Faraci FM, Sigmund CD. Interference with PPARγ in endothelium accelerates angiotensin II-induced endothelial dysfunction. Physiol Genomics 2015; 48:124-34. [PMID: 26534936 DOI: 10.1152/physiolgenomics.00087.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/02/2015] [Indexed: 02/07/2023] Open
Abstract
The ligand activated nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) in the endothelium regulates vascular function and blood pressure (BP). We previously reported that transgenic mice (E-V290M) with selectively targeted endothelial-specific expression of dominant negative PPARγ exhibited endothelial dysfunction when treated with a high-fat diet, and exhibited an augmented pressor response to angiotensin II (ANG II). We hypothesize that interference with endothelial PPARγ would exacerbate ANG II-induced endothelial dysfunction. Endothelial function was examined in E-V290M mice infused with a subpressor dose of ANG II (120 ng·kg(-1)·min(-1)) or saline for 2 wk. ANG II infusion significantly impaired the responses to the endothelium-dependent agonist acetylcholine both in basilar and carotid arteries from E-V290M but not NT mice. This impairment was not due to increased BP, which was not significantly different in ANG II-infused E-V290M compared with NT mice. Superoxide levels, and expression of the pro-oxidant Nox2 gene was elevated, whereas expression of the anti-oxidant genes Catalase and SOD3 decreased in carotid arteries from ANG II-infused E-V290M mice. Increased p65 and decreased Iκ-Bα suggesting increased NF-κB activity was also observed in aorta from ANG II-infused E-V290M mice. The responses to acetylcholine were significantly improved both in basilar and carotid arteries after treatment with Tempol (1 mmol/l), a scavenger of superoxide. These findings provide evidence that interference with endothelial PPARγ accelerates ANG II-mediated endothelial dysfunction both in cerebral and conduit arteries through an oxidative stress-dependent mechanism, suggesting a role for endothelial PPARγ in protecting against ANG II-induced endothelial dysfunction.
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Affiliation(s)
- Chunyan Hu
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Ko-Ting Lu
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Masashi Mukohda
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Deborah R Davis
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Frank M Faraci
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and Iowa City Veterans Affairs Healthcare System, Iowa City, Iowa
| | - Curt D Sigmund
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
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Bai J, Lyden PD. Revisiting Cerebral Postischemic Reperfusion Injury: New Insights in Understanding Reperfusion Failure, Hemorrhage, and Edema. Int J Stroke 2015; 10:143-52. [DOI: 10.1111/ijs.12434] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/14/2014] [Indexed: 01/11/2023]
Abstract
Cerebral postischemic reperfusion injury is defined as deterioration of ischemic brain tissue that parallels and antagonizes the benefits of restoring cerebral circulation after therapeutic thrombolysis for acute ischemic stroke. To understand the paradox of injury caused by treatment, we first emphasize the phenomenon in which recanalization of an occluded artery does not lead to tissue reperfusion. Additionally, no-reflow after recanalization may be due to injury of the neurovascular unit, distal microthrombosis, or both, and certainly worsens outcome. We examine the mechanism of molecular and sub-cellular damage in the neurovascular unit, notably oxidative stress, mitochondrial dysfunction, and apoptosis. At the level of the neurovascular unit, which mediates crosstalk between the damaged brain and systemic responses in blood, we summarize emerging evidence demonstrating that individual cell components play unique and cumulative roles that lead to damage of the blood–brain barrier and neurons. Furthermore, we review the latest developments in establishing a link between the immune system and microvascular dysfunction during ischemic reperfusion. Progress in assessing reperfusion injury has also been made, and we review imaging studies using various magnetic resonance imaging modalities. Lastly, we explore potential treatment approaches, including ischemic preconditioning, postconditioning, pharmacologic agents, and hypothermia.
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Affiliation(s)
- Jilin Bai
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Patrick D. Lyden
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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Vascular dysfunctions in the isolated aorta of double-transgenic hypertensive mice developing aortic aneurysm. Pflugers Arch 2014; 467:1945-63. [PMID: 25385304 DOI: 10.1007/s00424-014-1644-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/29/2014] [Accepted: 10/31/2014] [Indexed: 01/09/2023]
Abstract
Angiotensin-II and oxidative stress are involved in the genesis of aortic aneurysms, a phenomenon exacerbated by endothelial nitric oxide synthase (eNOS) deletion or uncoupling. The purpose of this work was to study the endothelial function in wild-type C57BL/6 (BL) and transgenic mice expressing the h-angiotensinogen and h-renin genes (AR) subjected to either a control, or a high-salt diet plus a treatment with a NO-synthase inhibitor, N-ω-nitro-L-arginine-methyl-ester (L-NAME; BLSL and ARSL). BLSL showed a moderate increase in blood pressure, while ARSL became severely hypertensive. Seventy-five percent of ARSL developed aortic aneurysms, characterized by major histo-morphological changes and associated with an increase in NADP(H) oxidase-2 (NOX2) expression. Contractile responses (KCl, norepinephrine, U-46619) were similar in the four groups of mice, and relaxations were not affected in BLSL and AR. However, in ARSL, endothelium-dependent relaxations (acetylcholine, UK-14304) were significantly reduced, and this dysfunction was similar in aortae without or with aneurysms. The endothelial impairment was unaffected by catalase, superoxide-dismutase mimetic, radical scavengers, cyclooxygenase inhibition, or TP-receptor blockade and could not be attributed to sGC oxidation. Thus, ARSL is a severe hypertension model developing aortic aneurysm. A vascular dysfunction, involving both endothelial (reduced role of NO) and smooth muscle cells, precedes aneurysms formation and, paradoxically, does not appear to involve oxidative stress.
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Gomolak JR, Didion SP. Angiotensin II-induced endothelial dysfunction is temporally linked with increases in interleukin-6 and vascular macrophage accumulation. Front Physiol 2014; 5:396. [PMID: 25400581 PMCID: PMC4212611 DOI: 10.3389/fphys.2014.00396] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 09/24/2014] [Indexed: 01/18/2023] Open
Abstract
Angiotensin II (Ang II) is associated with vascular hypertrophy, endothelial dysfunction and activation of a number of inflammatory molecules, however the linear events involved in the development of hypertension and endothelial dysfunction produced in response to Ang II are not well defined. The goal of this study was to examine the dose- and temporal-dependent development of endothelial dysfunction in response to Ang II. Blood pressure and responses of carotid arteries were examined in control (C57Bl/6) mice and in mice infused with 50, 100, 200, 400, or 1000 ng/kg/min Ang II for either 14 or 28 Days. Infusion of Ang II was associated with graded and marked increases in systolic blood pressure and plasma Ang II concentrations. While low doses of Ang II (i.e., 50 and 100 ng/kg/min) had little to no effect on blood pressure or endothelial function, high doses of Ang II (e.g., 1000 ng/kg/min) were associated with large increases in arterial pressure and marked impairment of endothelial function. In contrast, intermediate doses of Ang II (200 and 400 ng/kg/min) while initially having no effect on systolic blood pressure were associated with significant increases in pressure over time. Despite increasing blood pressure, 200 ng/kg/min had no effect on endothelial function, whereas 400 ng/kg/min produced modest impairment on Day 14 and marked impairment of endothelial function on Day 28. The degree of endothelial dysfunction produced by 400 and 1000 ng/kg/min Ang II was reflective of parallel increases in plasma IL-6 levels and vascular macrophage content, suggesting that increases in arterial blood pressure precede the development of endothelial dysfunction. These findings are important as they demonstrate that along with increases in arterial pressure that increases in IL-6 and vascular macrophage accumulation correlate with the impairment of endothelial function produced by Ang II.
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Affiliation(s)
- Jessica R Gomolak
- Department of Pharmacology, The University of Mississippi Medical Center Jackson, MS, USA
| | - Sean P Didion
- Department of Pharmacology, The University of Mississippi Medical Center Jackson, MS, USA ; Department of Neurology, The University of Mississippi Medical Center Jackson, MS, USA
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Zheng J, Li G, Chen S, Bihl J, Buck J, Zhu Y, Xia H, Lazartigues E, Chen Y, Olson JE. Activation of the ACE2/Ang-(1-7)/Mas pathway reduces oxygen-glucose deprivation-induced tissue swelling, ROS production, and cell death in mouse brain with angiotensin II overproduction. Neuroscience 2014; 273:39-51. [PMID: 24814023 DOI: 10.1016/j.neuroscience.2014.04.060] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 04/14/2014] [Accepted: 04/29/2014] [Indexed: 12/16/2022]
Abstract
We previously demonstrated that mice which overexpress human renin and angiotensinogen (R+A+) show enhanced cerebral damage in both in vivo and in vitro experimental ischemia models. Angiotensin-converting enzyme 2 (ACE2) counteracts the effects of angiotensin (Ang-II) by transforming it into Ang-(1-7), thus reducing the ligand for the AT1 receptor and increasing stimulation of the Mas receptor. Triple transgenic mice, SARA, which specifically overexpress ACE2 in neurons of R+A+ mice were used to study the role of ACE2 in ischemic stroke using oxygen and glucose deprivation (OGD) of brain slices as an in vitro model. We examined tissue swelling, the production of reactive oxygen species (ROS), and cell death in the cerebral cortex (CX) and the hippocampal CA1 region during OGD. Expression levels of NADPH oxidase (Nox) isoforms, Nox2 and Nox4 were measured using western blots. Results show that SARA mice and R+A+ mice treated with the Mas receptor agonist Ang-(1-7) had less swelling, cell death, and ROS production in CX and CA1 areas compared to those in R+A+ animals. Treatment of slices from SARA mice with the Mas antagonist A779 eliminated this protection. Finally, western blots revealed less Nox2 and Nox4 expression in SARA mice compared with R+A+ mice both before and after OGD. We suggest that reduced brain swelling and cell death observed in SARA animals exposed to OGD result from diminished ROS production coupled with lower expression of Nox isoforms. Thus, the ACE2/Ang-(1-7)/Mas receptor pathway plays a protective role in brain ischemic damage by counteracting the detrimental effects of Ang-II-induced ROS production.
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Affiliation(s)
- J Zheng
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, OH, United States; Department of Neurology, Second Affiliated Hospital, Harbin Medical University, China
| | - G Li
- Department of Emergency Medicine, Wright State University, Boonshoft School of Medicine, Dayton, OH, United States
| | - S Chen
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, OH, United States
| | - J Bihl
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, OH, United States
| | - J Buck
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, OH, United States
| | - Y Zhu
- Department of Neurology, Second Affiliated Hospital, Harbin Medical University, China
| | - H Xia
- Department of Pharmacology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - E Lazartigues
- Department of Pharmacology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Y Chen
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, OH, United States.
| | - J E Olson
- Department of Emergency Medicine, Wright State University, Boonshoft School of Medicine, Dayton, OH, United States; Department of Neuroscience, Cell Biology and Physiology, Wright State University, Boonshoft School of Medicine, Dayton, OH, United States.
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12
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Gashev AA, Chatterjee V. Aged lymphatic contractility: recent answers and new questions. Lymphat Res Biol 2013; 11:2-13. [PMID: 23531179 DOI: 10.1089/lrb.2013.0003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Abstract An overview is presented of recent findings related to biology of aging of the lymph transport system. The authors discuss recently obtained data on the aging-associated alterations of lymphatic contractility in thoracic duct and mesenteric lymphatic vessels; on comparisons of function of aged mesenteric lymphatic vessels in situ versus isolated specimens and important conclusions which arose from these studies; on aging-associated changes in functional status of mast cells located close to aged mesenteric lymphatic vessels; on evidence of presence of oxidative stress in aged lymphatic vessels and changes in arrangement of muscle cells in their walls. The authors conclude that future continuation of the research efforts in this area is necessary and will be able to provide not only novel fundamental knowledge on the biology of lymphatic aging, but also will create solid foundation for the subsequent developments of lymphatic-oriented therapeutic interventions in many diseases of the elderly.
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Affiliation(s)
- Anatoliy A Gashev
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Temple, Texas 76504, USA.
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Chan SL, Baumbach GL. Deficiency of Nox2 prevents angiotensin II-induced inward remodeling in cerebral arterioles. Front Physiol 2013; 4:133. [PMID: 23805104 PMCID: PMC3693079 DOI: 10.3389/fphys.2013.00133] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Accepted: 05/20/2013] [Indexed: 01/26/2023] Open
Abstract
Angiotensin II is an important determinant of inward remodeling in cerebral arterioles. Many of the vascular effects of angiotensin II are mediated by reactive oxygen species (ROS) generated from homologs of NADPH oxidase with Nox2 predominating in small arteries and arterioles. Therefore, we tested the hypothesis that superoxide generated by Nox2 plays a role in angiotensin II-induced cerebral arteriolar remodeling. We examined Nox2-deficient and wild-type (WT) mice in which a pressor or a non-pressor dose of angiotensin II (1000 or 200 ng/kg/day) or saline was infused for 4 weeks via osmotic minipumps. Systolic arterial pressure was measured by a tail-cuff method. Pressure and diameter of cerebral arterioles were measured through an open cranial window in anesthetized mice. Cross-sectional area (by histology) and superoxide level (by hydroethidine staining) of cerebral arterioles were determined ex vivo. The pressor, but not the non-pressor, dose of angiotensin II significantly increased systolic arterial pressure in both WT and Nox2-deficient mice. Both doses of angiotensin II increased superoxide levels and significantly reduced external diameter in maximally dilated cerebral arterioles in WT mice. Increased superoxide and inward remodeling were prevented in Nox2-deficient mice. Moreover, only the pressor dose of AngII increased cross-sectional area of arteriolar wall in WT mice and was prevented in Nox2-deficient mice. In conclusion, superoxide derived from Nox2-containing NADPH oxidase plays an important role in angiotensin II-mediated inward remodeling in cerebral arterioles. This effect appears to be independent of pressure and different from that of hypertrophy.
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Affiliation(s)
- Siu-Lung Chan
- Department of Pathology, University of Iowa Carver College of Medicine Iowa City, IA, USA
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14
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Abstract
It is increasingly apparent that not only is a cure for the current worldwide diabetes epidemic required, but also for its major complications, affecting both small and large blood vessels. These complications occur in the majority of individuals with both type 1 and type 2 diabetes. Among the most prevalent microvascular complications are kidney disease, blindness, and amputations, with current therapies only slowing disease progression. Impaired kidney function, exhibited as a reduced glomerular filtration rate, is also a major risk factor for macrovascular complications, such as heart attacks and strokes. There have been a large number of new therapies tested in clinical trials for diabetic complications, with, in general, rather disappointing results. Indeed, it remains to be fully defined as to which pathways in diabetic complications are essentially protective rather than pathological, in terms of their effects on the underlying disease process. Furthermore, seemingly independent pathways are also showing significant interactions with each other to exacerbate pathology. Interestingly, some of these pathways may not only play key roles in complications but also in the development of diabetes per se. This review aims to comprehensively discuss the well validated, as well as putative mechanisms involved in the development of diabetic complications. In addition, new fields of research, which warrant further investigation as potential therapeutic targets of the future, will be highlighted.
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Affiliation(s)
- Josephine M Forbes
- Diabetes Division, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
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15
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Santhanam AVR, d'Uscio LV, Smith LA, Katusic ZS. Uncoupling of eNOS causes superoxide anion production and impairs NO signaling in the cerebral microvessels of hph-1 mice. J Neurochem 2012; 122:1211-8. [PMID: 22784235 DOI: 10.1111/j.1471-4159.2012.07872.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this study, we used the GTP cyclohydrolase I-deficient mice, i.e., hyperphenylalaninemic (hph-1) mice, to test the hypothesis that the loss of tetrahydrobiopterin (BH(4)) in cerebral microvessels causes endothelial nitric oxide synthase (eNOS) uncoupling, resulting in increased superoxide anion production and inhibition of endothelial nitric oxide signaling. Both homozygous mutant (hph-1(-/-)) and heterozygous mutant (hph-1(+/-) mice) demonstrated reduction in GTP cyclohydrolase I activity and reduced bioavailability of BH(4). In the cerebral microvessels of hph-1(+/-) and hph-1(-/-) mice, increased superoxide anion production was inhibited by supplementation of BH(4) or NOS inhibitor- L- N(G) -nitro arginine-methyl ester, indicative of eNOS uncoupling. Expression of 3-nitrotyrosine was significantly increased, whereas NO production and cGMP levels were significantly reduced. Expressions of antioxidant enzymes namely copper and zinc superoxide dismutase, manganese superoxide dismutase, and catalase were not affected by uncoupling of eNOS. Reduced levels of BH(4), increased superoxide anion production, as well as inhibition of NO signaling were not different between the microvessels of male and female mice. The results of our study are the first to demonstrate that, regardless of gender, reduced BH(4) bioavailability causes eNOS uncoupling, increases superoxide anion production, inhibits eNOS/cGMP signaling, and imposes significant oxidative stress in the cerebral microvasculature.
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Affiliation(s)
- Anantha Vijay R Santhanam
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, USA
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16
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Thangaswamy S, Bridenbaugh EA, Gashev AA. Evidence of increased oxidative stress in aged mesenteric lymphatic vessels. Lymphat Res Biol 2012; 10:53-62. [PMID: 22540739 DOI: 10.1089/lrb.2011.0022] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND We have previously shown that aging is associated with weakened rat mesenteric lymphatic vessel (MLV) contractility. However, the specific mechanisms contributing to this aging-associated contractile degeneration remain unknown. Aging is often associated with elevations in oxidative stress, and reactive oxygen species (ROS) have been shown to reduce the contractility of MLV. Thus in the present study, we sought to assess whether aging is associated with increased levels of oxidative stress and oxidative damage in MLV. METHODS AND RESULTS MLV were isolated from 9-mo- and 24-mo-old Fischer-344 rats and subjected to the following experimental techniques: measurement of total superoxide dismutase (SOD) activity; estimation of lipid peroxidation levels via measurement of thiobarbituric acid reactive substances (TBARS); detection of superoxide and mitochondrial ROS in live MLV; Western blot analysis, and immunohistochemical labeling of the SOD isoforms and nitro-tyrosine proteins. We found that aging is associated with increased levels of cellular superoxide and mitochondrial ROS concomitant with a reduction in Cu/Zn-SOD protein expression and total SOD enzymatic activity in MLV. This increase in oxidative stress and decrease in antioxidant activity was associated with evidence of increased lipid (as indicated by TBARS) and protein (as indicated by nitro-tyrosine labeling) oxidative damage. CONCLUSIONS Thus for the first time, we demonstrate that aging-associated increases in oxidative stress and oxidative damage is indeed present in the walls of MLV and may contribute to the aging-associated lymphatic pump dysfunction we previously reported.
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Affiliation(s)
- Sangeetha Thangaswamy
- Department of Systems Biology and Translational Medicine, College of Medicine, Texas A&M Health Science Center, Temple, Texas 76504, USA
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17
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Wingler K, Hermans JJR, Schiffers P, Moens A, Paul M, Schmidt HHHW. NOX1, 2, 4, 5: counting out oxidative stress. Br J Pharmacol 2012; 164:866-83. [PMID: 21323893 PMCID: PMC3195911 DOI: 10.1111/j.1476-5381.2011.01249.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
For decades, oxidative stress has been discussed as a key mechanism of endothelial dysfunction and cardiovascular disease. However, attempts to validate and exploit this hypothesis clinically by supplementing antioxidants have failed. Nevertheless, this does not disprove the oxidative stress hypothesis. As a certain degree of reactive oxygen species (ROS) formation appears to be physiological and beneficial. To reduce oxidative stress therapeutically, two alternative approaches are being developed. One is the repair of key signalling components that are compromised by oxidative stress. These include uncoupled endothelial nitric oxide (NO) synthase and oxidized/heme-free NO receptor soluble guanylate cyclase. A second approach is to identify and effectively inhibit the relevant source(s) of ROS in a given disease condition. A highly likely target in this context is the family of NADPH oxidases. Animal models, including NOX knockout mice and new pharmacological inhibitors of NADPH oxidases have opened up a new era of oxidative stress research and have paved the way for new cardiovascular therapies.
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Affiliation(s)
- K Wingler
- Department of Pharmacology & Cardiovascular Research Institute Maastricht, Maastricht University, the Netherlands
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18
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Abstract
Endothelial cells exert an enormous influence on blood vessels throughout the circulation, but their impact is particularly pronounced in the brain. New concepts have emerged recently regarding the role of this cell type and mechanisms that contribute to endothelial dysfunction and vascular disease. Activation of the renin-angiotensin system plays a prominent role in producing these abnormalities. Both oxidative stress and local inflammation are key mechanisms that underlie vascular disease of diverse etiology. Endogenous mechanisms of vascular protection are also present, including antioxidants, anti-inflammatory molecules, and peroxisome proliferator-activated receptor-γ. Despite their clear importance, studies of mechanisms that underlie cerebrovascular disease continue to lag behind studies of vascular biology in general. Identification of endogenous molecules and pathways that protect the vasculature may result in targeted approaches to prevent or slow the progression of vascular disease that causes stroke and contributes to the vascular component of dementia and Alzheimer's disease.
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Affiliation(s)
- Frank M Faraci
- Dept. of Internal Medicine, Carver College of Medicine, Univ. of Iowa, Iowa City, Iowa 52242-1081, USA.
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Lesniewski LA, Durrant JR, Connell ML, Folian BJ, Donato AJ, Seals DR. Salicylate treatment improves age-associated vascular endothelial dysfunction: potential role of nuclear factor kappaB and forkhead Box O phosphorylation. J Gerontol A Biol Sci Med Sci 2011; 66:409-18. [PMID: 21303813 DOI: 10.1093/gerona/glq233] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We hypothesized that I kappa B kinase (IKK)-mediated nuclear factor kappa B and forkhead BoxO3a phosphorylation will be associated with age-related endothelial dysfunction. Endothelium-dependent dilation and aortic protein expression/phosphorylation were determined in young and old male B6D2F1 mice and old mice treated with the IKK inhibitor, salicylate. IKK activation was greater in old mice and was associated with greater nitrotyrosine and cytokines. Endothelium-dependent dilation, nitric oxide (NO), and endothelial NO synthase phosphorylation were lower in old mice. Endothelium-dependent dilation and NO bioavailability were restored by a superoxide dismutase mimetic. Nuclear factor kappa B and forkhead BoxO3a phosphorylation were greater in old and were associated with increased expression/activity of nicotinamide adenine dinucleotide phosphate oxidase and lower manganese superoxide dismutase expression. Salicylate lowered IKK phosphorylation and reversed age-associated changes in nitrotyrosine, endothelium-dependent dilation, NO bioavailability, endothelial NO synthase, nuclear factor kappa B and forkhead BoxO3a phosphorylation, nicotinamide adenine dinucleotide phosphate oxidase, and manganese superoxide dismutase. Increased activation of IKK with advancing age stimulates nuclear factor kappa B and inactivates forkhead BoxO3a. This altered transcription factor activation contributes to a pro-inflammatory/pro-oxidative arterial phenotype that is characterized by increased cytokines and nicotinamide adenine dinucleotide phosphate oxidase and decreased manganese superoxide dismutase leading to oxidative stress-mediated endothelial dysfunction.
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Affiliation(s)
- Lisa A Lesniewski
- Department of Integrative Physiology, University of Colorado at Boulder, USA.
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20
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21
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Kopf PG, Scott JA, Agbor LN, Boberg JR, Elased KM, Huwe JK, Walker MK. Cytochrome P4501A1 is required for vascular dysfunction and hypertension induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol Sci 2010; 117:537-46. [PMID: 20634294 DOI: 10.1093/toxsci/kfq218] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
National Health and Nutrition Examination Survey data show an association between hypertension and exposure to dioxin-like halogenated aromatic hydrocarbons (HAHs). Furthermore, chronic exposure of mice to the prototypical HAH, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), induces reactive oxygen species (ROS), endothelial dysfunction, and hypertension. Because TCDD induces cytochrome P4501A1 (CYP1A1) and CYP1A1 can increase ROS, we tested the hypothesis that TCDD-induced endothelial dysfunction and hypertension are mediated by CYP1A1. CYP1A1 wild-type (WT) and knockout (KO) mice were fed one control or TCDD-containing pill (180 ng TCDD/kg, 5 days/week) for 35 days (n = 10-14/genotype/treatment). Blood pressure was monitored by radiotelemetry, and liver TCDD concentration, CYP1A1 induction, ROS, and aortic reactivity were measured at 35 days. TCDD accumulated to similar levels in livers of both genotypes. TCDD induced CYP1A1 in endothelium of aorta and mesentery without detectable expression in the vessel wall. TCDD also induced superoxide anion production, measured by NADPH-dependent lucigenin luminescence, in aorta, heart, and kidney of CYP1A1 WT mice but not KO mice. In contrast, TCDD induced hydrogen peroxide, measured by amplex red assay, to similar levels in aorta of CYP1A1 WT and KO mice but not in heart or kidney. TCDD reduced acetylcholine-dependent vasorelaxation in aortic rings of CYP1A1 WT mice but not in KO mice. Finally, TCDD steadily increased blood pressure after 15 days, which plateaued after 25 days (+20 mmHg) in CYP1A1 WT mice but failed to alter blood pressure in KO mice. These results demonstrate that CYP1A1 is required for TCDD-induced cardiovascular superoxide anion production, endothelial dysfunction, and hypertension.
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Affiliation(s)
- Phillip G Kopf
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, New Mexico 87131, USA
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Zielonka J, Kalyanaraman B. Hydroethidine- and MitoSOX-derived red fluorescence is not a reliable indicator of intracellular superoxide formation: another inconvenient truth. Free Radic Biol Med 2010; 48:983-1001. [PMID: 20116425 PMCID: PMC3587154 DOI: 10.1016/j.freeradbiomed.2010.01.028] [Citation(s) in RCA: 393] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 01/20/2010] [Accepted: 01/21/2010] [Indexed: 12/15/2022]
Abstract
Hydroethidine (HE; or dihydroethidium) is the most popular fluorogenic probe used for detecting intracellular superoxide radical anion. The reaction between superoxide and HE generates a highly specific red fluorescent product, 2-hydroxyethidium (2-OH-E(+)). In biological systems, another red fluorescent product, ethidium, is also formed, usually at a much higher concentration than 2-OH-E(+). In this article, we review the methods to selectively detect the superoxide-specific product (2-OH-E(+)) and the factors affecting its levels in cellular and biological systems. The most important conclusion of this review is that it is nearly impossible to assess the intracellular levels of the superoxide-specific product, 2-OH-E(+), using confocal microscopy or other fluorescence-based microscopic assays and that it is essential to measure by HPLC the intracellular HE and other oxidation products of HE, in addition to 2-OH-E(+), to fully understand the origin of red fluorescence. The chemical reactivity of mitochondria-targeted hydroethidine (Mito-HE, MitoSOX red) with superoxide is similar to the reactivity of HE with superoxide, and therefore, all of the limitations attributed to the HE assay are applicable to Mito-HE (or MitoSOX) as well.
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Affiliation(s)
- Jacek Zielonka
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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23
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Abstract
Oxidative stress and matrix metalloproteinases (MMPs) contribute to hemorrhagic transformation after ischemic stroke and brain injury after intracerebral hemorrhage (ICH). The goal of this study was to develop a new model of spontaneous ICH, based on the hypothesis that acute, superimposed on chronic, hypertension produces ICH. We hypothesized that increases in angiotensin II (AngII)-mediated oxidative stress and activation of MMPs are associated with, and may precede, spontaneous ICH during hypertension. In C57BL/6 mice, chronic hypertension was produced with AngII infusion and an inhibitor of nitric oxide synthase. During chronic hypertension, mice with acute hypertension from injections of AngII developed ICH. Oxidative stress and MMP levels increased in the brain even before developing ICH. Active MMPs colocalized with a marker of oxidative stress, especially on cerebral vessels that appeared to lead toward regions with ICH. Incidence of ICH and levels of oxidative stress and MMP-9 were greater in mice with acute hypertension produced by AngII than by norepinephrine. In summary, we have developed an experimental model of ICH during hypertension that may facilitate studies in genetically altered mice. We speculate that acute hypertension, especially when induced by AngII, may be critical in spontaneous ICH during chronic hypertension, possibly through oxidative stress and MMP-9.
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Falcao S, Stoyanova E, Cloutier G, Maurice RL, Gutkowska J, Lavoie JL. Mice Overexpressing Both Human Angiotensinogen and Human Renin as a Model of Superimposed Preeclampsia on Chronic Hypertension. Hypertension 2009; 54:1401-7. [DOI: 10.1161/hypertensionaha.109.137356] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Stéphanie Falcao
- From the Laboratory of Biorheology and Medical Ultrasonics (E.S., G.C., R.L.M.), CRCHUM (S.F., J.G., J.L.L.), Montréal, Québec, Canada; Departments of Biomedical Sciences (S.F., E.S.), Radiology, Radio-Oncology, and Nuclear Medicine (G.C., R.L.M.), and Medicine (J.G., J.L.L.), and Institute of Biomedical Engineering (G.C., R.L.M.), Université de Montréal, Montréal, Québec, Canada
| | - Ekatherina Stoyanova
- From the Laboratory of Biorheology and Medical Ultrasonics (E.S., G.C., R.L.M.), CRCHUM (S.F., J.G., J.L.L.), Montréal, Québec, Canada; Departments of Biomedical Sciences (S.F., E.S.), Radiology, Radio-Oncology, and Nuclear Medicine (G.C., R.L.M.), and Medicine (J.G., J.L.L.), and Institute of Biomedical Engineering (G.C., R.L.M.), Université de Montréal, Montréal, Québec, Canada
| | - Guy Cloutier
- From the Laboratory of Biorheology and Medical Ultrasonics (E.S., G.C., R.L.M.), CRCHUM (S.F., J.G., J.L.L.), Montréal, Québec, Canada; Departments of Biomedical Sciences (S.F., E.S.), Radiology, Radio-Oncology, and Nuclear Medicine (G.C., R.L.M.), and Medicine (J.G., J.L.L.), and Institute of Biomedical Engineering (G.C., R.L.M.), Université de Montréal, Montréal, Québec, Canada
| | - Roch L. Maurice
- From the Laboratory of Biorheology and Medical Ultrasonics (E.S., G.C., R.L.M.), CRCHUM (S.F., J.G., J.L.L.), Montréal, Québec, Canada; Departments of Biomedical Sciences (S.F., E.S.), Radiology, Radio-Oncology, and Nuclear Medicine (G.C., R.L.M.), and Medicine (J.G., J.L.L.), and Institute of Biomedical Engineering (G.C., R.L.M.), Université de Montréal, Montréal, Québec, Canada
| | - Jolanta Gutkowska
- From the Laboratory of Biorheology and Medical Ultrasonics (E.S., G.C., R.L.M.), CRCHUM (S.F., J.G., J.L.L.), Montréal, Québec, Canada; Departments of Biomedical Sciences (S.F., E.S.), Radiology, Radio-Oncology, and Nuclear Medicine (G.C., R.L.M.), and Medicine (J.G., J.L.L.), and Institute of Biomedical Engineering (G.C., R.L.M.), Université de Montréal, Montréal, Québec, Canada
| | - Julie L. Lavoie
- From the Laboratory of Biorheology and Medical Ultrasonics (E.S., G.C., R.L.M.), CRCHUM (S.F., J.G., J.L.L.), Montréal, Québec, Canada; Departments of Biomedical Sciences (S.F., E.S.), Radiology, Radio-Oncology, and Nuclear Medicine (G.C., R.L.M.), and Medicine (J.G., J.L.L.), and Institute of Biomedical Engineering (G.C., R.L.M.), Université de Montréal, Montréal, Québec, Canada
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Simvastatin improves cerebrovascular function and counters soluble amyloid-beta, inflammation and oxidative stress in aged APP mice. Neurobiol Dis 2009; 35:406-14. [DOI: 10.1016/j.nbd.2009.06.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 05/29/2009] [Accepted: 06/04/2009] [Indexed: 11/18/2022] Open
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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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Bäumer AT, Krüger CA, Falkenberg J, Freyhaus HT, Rösen R, Fink K, Rosenkranz S. The NAD(P)H Oxidase Inhibitor Apocynin Improves Endothelial NO/Superoxide Balance and Lowers Effectively Blood Pressure in Spontaneously Hypertensive Rats: Comparison to Calcium Channel Blockade. Clin Exp Hypertens 2009; 29:287-99. [PMID: 17653964 DOI: 10.1080/10641960701500398] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The vascular NAD(P)H oxidase contributes to endothelial dysfunction and high blood pressure in the spontaneously hypertensive rat by enhancing superoxide production. We investigated the effects of apocynin, a NAD(P)H oxidase inhibitor, on blood pressure and vascular radical and nitric oxide formation in SHR and compared its effects to the calcium channel blocker nifedipine. Apocynin (over four weeks) lowered systolic blood pressure significantly and as effectively as nifedipine. Both apocynin and nifedipine significantly reduced superoxide production. In parallel, vascular nitric oxide production and ecNOS activity was significantly increased by apocynin treatment. Therefore, apocynin may be an effective antihypertensive drug in essential hypertension.
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Affiliation(s)
- Anselm T Bäumer
- Klinik III für Innere Medizin, Universität zu Köln, Köln, Germany.
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Modrick ML, Didion SP, Lynch CM, Dayal S, Lentz SR, Faraci FM. Role of hydrogen peroxide and the impact of glutathione peroxidase-1 in regulation of cerebral vascular tone. J Cereb Blood Flow Metab 2009; 29:1130-7. [PMID: 19352401 PMCID: PMC2852621 DOI: 10.1038/jcbfm.2009.37] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although arachidonic acid (AA) has diverse vascular effects, the mechanisms that mediate these effects are incompletely defined. The goal of our study was to use genetic approaches to examine the role of hydrogen peroxide (H2O2), glutathione peroxidase (Gpx1, which degrades H2O2), and CuZn-superoxide dismutase (SOD1, which produces H2O2 from superoxide) in mediating and in determining vascular responses to AA. In basilar arteries in vitro, AA produced dilation in nontransgenic mice, and this response was reduced markedly in transgenic mice overexpressing Gpx1 (Gpx1 Tg) or in those genetically deficient in SOD1. For example, AA (1 nmol/L to 1 mumol/L) dilated the basilar artery and this response was reduced by approximately 90% in Gpx1 Tg mice (P<0.01), although responses to acetylcholine were not altered. Dilation of cerebral arterioles in vivo in response to AA was inhibited by approximately 50% by treatment with catalase (300 U/mL) (P<0.05) and reduced by as much as 90% in Gpx1 Tg mice compared with that in controls (P<0.05). These results provide the first evidence that Gpx1 has functional effects in the cerebral circulation, and that AA-induced vascular effects are mediated by H2O2 produced by SOD1. In contrast, cerebral vascular responses to the endothelium-dependent agonist acetylcholine are not mediated by H2O2.
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Affiliation(s)
- Mary L Modrick
- Department of Internal Medicine, Cardiovascular Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242-1081, USA
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Oxidative stress through activation of NAD(P)H oxidase in hypertensive mice with spontaneous intracranial hemorrhage. J Cereb Blood Flow Metab 2008; 28:1175-85. [PMID: 18301433 PMCID: PMC3153951 DOI: 10.1038/jcbfm.2008.7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We have developed an experimental model of spontaneous intracranial hemorrhage (ICH) in transgenic mice expressing human renin and human angiotensinogen (R+/A+) treated with high-salt diet and N(omega)-nitro-L-arginine methyl ester (L-NAME). We investigated whether oxidative stress is associated with spontaneous ICH in R+/A+ mice. R+/A+ mice on high-salt diet and L-NAME presented neurologic signs 57+/-13 (mean+/-s.e.m.) days after the start of treatment. Intracranial hemorrhage was shown with histologic examination. Levels of superoxide in brain homogenate were significantly increased in R+/A+ mice with ICH (118+/-10 RLU per sec per mg; RLU, relative light unit) compared with age-matched control mice (19+/-1) and R+/A+ mice without ICH (53+/-3). NAD(P)H oxidase activity was significantly higher in R+/A+ mice with ICH (34,933+/-2,420 RLU per sec per mg) than in control mice (4,984+/-248) and R+/A+ mice without ICH (15,069+/-917). These results suggest that increased levels of superoxide are due, at least in part, to increased NAD(P)H oxidase activity. Increased NAD(P)H oxidase activity preceded signs of ICH, and increased further when R+/A+ mice developed ICH. These findings suggest that oxidative stress may contribute to spontaneous ICH in chronic hypertension.
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31
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Schrader LI, Kinzenbaw DA, Johnson AW, Faraci FM, Didion SP. IL-6 deficiency protects against angiotensin II induced endothelial dysfunction and hypertrophy. Arterioscler Thromb Vasc Biol 2007; 27:2576-81. [PMID: 17962626 DOI: 10.1161/atvbaha.107.153080] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The goal of this study was to test the hypothesis that IL-6 mediates the increases in superoxide, vascular hypertrophy, and endothelial dysfunction in response to angiotensin II (Ang II). METHODS AND RESULTS Responses of carotid arteries from control and IL-6-deficient mice were examined after acute (22-hour) incubation with Ang II (10 nmol/L) or chronic infusion of Ang II (1.4 mg/kg/d for 14 days). The hypertrophic response and endothelial dysfunction produced by Ang II infusion was markedly less in carotid arteries from IL-6-deficient mice than that in control mice. IL-6 deficiency also protected against endothelial dysfunction in response to acute (local) Ang II treatment (eg, 100 mumol/L acetylcholine produced 100+/-4 and 98+/-4% relaxation in vehicle-treated and 51+/-4 and 99+/-4% relaxation in Ang II-treated, control, and IL-6-deficient vessels, respectively). Endothelial dysfunction could be reproduced in vessels from IL-6-deficient mice with combined Ang II plus IL-6 (0.1 nmol/L) treatment. Increases in vascular superoxide and IL-6, as well as reductions in endothelial nitric oxide synthase mRNA expression, produced by Ang II were absent in IL-6-deficient mice. CONCLUSIONS These data demonstrate that IL-6 is essential for Ang II-induced increases in superoxide, endothelial dysfunction, and vascular hypertrophy.
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Affiliation(s)
- Laura I Schrader
- Department of Internal Medicine, Division of Cardiovascular Medicine, 340-G Eckstein Medical Research Building, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
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32
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Cooper SA, Whaley-Connell A, Habibi J, Wei Y, Lastra G, Manrique C, Stas S, Sowers JR. Renin-angiotensin-aldosterone system and oxidative stress in cardiovascular insulin resistance. Am J Physiol Heart Circ Physiol 2007; 293:H2009-23. [PMID: 17586614 DOI: 10.1152/ajpheart.00522.2007] [Citation(s) in RCA: 197] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hypertension commonly occurs in conjunction with insulin resistance and other components of the cardiometabolic syndrome. Insulin resistance plays a significant role in the relationship between hypertension, Type 2 diabetes mellitus, chronic kidney disease, and cardiovascular disease. There is accumulating evidence that insulin resistance occurs in cardiovascular and renal tissue as well as in classical metabolic tissues (i.e., skeletal muscle, liver, and adipose tissue). Activation of the renin-angiotensin-aldosterone system and subsequent elevations in angiotensin II and aldosterone, as seen in cardiometabolic syndrome, contribute to altered insulin/IGF-1 signaling pathways and reactive oxygen species formation to induce endothelial dysfunction and cardiovascular disease. This review examines currently understood mechanisms underlying the development of resistance to the metabolic actions of insulin in cardiovascular as well as skeletal muscle tissue.
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Affiliation(s)
- Shawna A Cooper
- Department of Internal Medicine, University of Missouri School of Medicine, Columbia, Missouri 65212, USA
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33
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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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34
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Ohashi M, Runge MS, Faraci FM, Heistad DD. MnSOD deficiency increases endothelial dysfunction in ApoE-deficient mice. Arterioscler Thromb Vasc Biol 2006; 26:2331-6. [PMID: 16873728 DOI: 10.1161/01.atv.0000238347.77590.c9] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE In mice that are heterozygous for mitochondrial superoxide dismutase (SOD2(+/-)) with apoE deficiency (apoE(-/-)), mitochondrial DNA damage increases formation of atherosclerotic lesions. The purpose of this study was to determine whether SOD2 provides protection against increased vascular superoxide and endothelial dysfunction in apoE-deficient mice. METHODS AND RESULTS Four groups of mice [apoE(-/-)/SOD2(+/-) (apoe/sod2), apoE(-/-)/SOD2(+/+) (apoe/SOD2), apoE(+/+)/SOD2(+/-) (apoE/sod2), and apoE(+/+)/SOD2(+/+) (apoE/SOD2)] were fed normal chow diet, and studied at 15 to 17 months of age. Serum cholesterol levels were similar in apoe/sod2 and apoe/SOD2 mice, and also were similar in apoE/sod2 and apoE/SOD2 mice. Intimal area was increased in aorta, but not carotid artery, of apoe/sod2 and apoe/SOD2 mice. In carotid artery, superoxide was increased (67+/-5.2 relative fluorescence intensity/vessel area [RI] in apoe/sod2 mice, 31+/-3.1 RI in apoE/SOD2 mice, P<0.05), and relaxation to acetylcholine was impaired in apoe/sod2 mice versus apoe/ SOD2, apoE/sod2, apoE/SOD2 mice. Tiron improved relaxation to acetylcholine. In aorta, superoxide levels were increased and relaxation to acetylcholine was impaired in apoe/sod2 and apoe/SOD2 mice, but responses were similar in apoe/sod2 and apoe/SOD2 mice. CONCLUSIONS SOD2 protects against oxidative stress and endothelial dysfunction in carotid artery of apoE-deficient mice.
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Affiliation(s)
- Masuo Ohashi
- Cardiovascular Center and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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35
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Baumbach GL, Didion SP, Faraci FM. Hypertrophy of Cerebral Arterioles in Mice Deficient in Expression of the Gene for CuZn Superoxide Dismutase. Stroke 2006; 37:1850-5. [PMID: 16763183 DOI: 10.1161/01.str.0000227236.84546.5a] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Reactive oxygen species are believed to be an important determinant of vascular growth. We examined effects of genetic deficiency of copper-zinc superoxide dismutase (CuZnSOD; SOD1) on structure and function of cerebral arterioles.
Methods—
Systemic arterial pressure (SAP) and cross-sectional area of the vessel wall (CSA) and superoxide (O
2
−
) levels (relative fluorescence of ethidium [ETH]) were examined in maximally dilated cerebral arterioles in mice with targeted disruption of one (+/−) or both (−/−) genes encoding CuZnSOD. Wild-type littermates served as controls. Vasodilator responses were tested in separate groups of mice.
Results—
CSA and ETH were significantly increased (
P
<0.05) in both CuZnSOD
+/−
and CuZnSOD
−/−
mice (CSA=435±24 and 541±48 μm
2
; ETH=18±1 and 34±2%) compared with wild-type mice (CSA=327±28 μm
2
; ETH=6%). Furthermore, the increases in CSA and ETH relative to wild-type mice were significantly greater (
P
<0.05) in CuZnSOD
−/−
mice than in CuZnSOD
+/−
mice (CSA=108 versus 214 μm
2
; ETH=12 versus 28%). In addition, dilatation of cerebral arterioles in response to acetylcholine, but not nitroprusside, was reduced by ≈25% in CuZnSOD
+/−
(
P
<0.075) and 50% in CuZnSOD
−/−
mice (
P
<0.05) compared with wild-type mice.
Conclusions—
Cerebral arterioles in CuZnSOD
+/−
and CuZnSOD
−/−
mice undergo marked hypertrophy. These findings provide the first direct evidence in any blood vessel that CuZnSOD normally inhibit
s
vascular hypertrophy suggesting that CuZnSOD plays a major role in regulation of cerebral vascular growth. The findings also suggest a gene dosing effect of CuZnSOD for increases in O
2
−
, induction of cerebral vascular hypertrophy and impaired endothelium-dependent dilatation.
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Affiliation(s)
- Gary L Baumbach
- Department of Pathology, University of Iowa College of Medicine, Iowa City, IA 52242, USA.
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36
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Girouard H, Park L, Anrather J, Zhou P, Iadecola C. Angiotensin II attenuates endothelium-dependent responses in the cerebral microcirculation through nox-2-derived radicals. Arterioscler Thromb Vasc Biol 2006; 26:826-32. [PMID: 16439707 DOI: 10.1161/01.atv.0000205849.22807.6e] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Angiotensin II (Ang II) exerts deleterious effect on the cerebral circulation through production of reactive oxygen species (ROS). However, the enzymatic source of the ROS has not been defined. We tested the hypothesis that Ang II impairs endothelium-dependent responses in the cerebral microcirculation through ROS generated in cerebrovascular cells by the enzyme NADPH oxidase. METHODS AND RESULTS Cerebral blood flow (CBF) was monitored by laser Doppler flowmetry in anesthetized mice equipped with a cranial window. Ang II (0.25+/-0.02 microg/kg per minute for 30 to 45 minutes) attenuated the CBF increase produced by the endothelium-dependent vasodilators acetylcholine (-42+/-5%; P<0.05), bradykinin (-53+/-5%; P<0.05), and A23187 (-43+/-4%; P<0.05), and induced cerebrovascular ROS production, assessed by hydroethidine fluoromicrography. These actions of Ang II were prevented by losartan, by the ROS scavenger Mn(III) tetrakis (4-benzoic acid) porphyrin chloride (100 micromol/L), or by the NADPH oxidase peptide inhibitor gp91ds-tat (1 micromol/L), and were not observed in mice lacking the NADPH oxidase subunit gp91phox (nox-2). CONCLUSIONS Ang II impairs the endothelial regulation of the cerebral microcirculation through AT1 receptor-mediated cerebrovascular oxidative stress. The source of the ROS is a nox-2-containing NADPH oxidase. These effects of Ang II could threaten the cerebral blood supply and contribute to the increased susceptibility to stroke and dementia associated with hypertension.
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Affiliation(s)
- Helene Girouard
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College, Cornell University, New York, NY 10021, USA
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37
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Didion SP, Kinzenbaw DA, Faraci FM. Critical role for CuZn-superoxide dismutase in preventing angiotensin II-induced endothelial dysfunction. Hypertension 2005; 46:1147-53. [PMID: 16216984 DOI: 10.1161/01.hyp.0000187532.80697.15] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The goal of the present study was to test the hypothesis that the CuZn isoform of superoxide dismutase (CuZnSOD) protects against angiotensin II (Ang II)-induced endothelial dysfunction. Vascular responses of carotid arteries from control, CuZnSOD-deficient (CuZnSOD(+/-)), and CuZnSOD transgenic mice were examined in vitro after overnight incubation with either vehicle or Ang II (1 or 10 nmol/L). In control mice, acetylcholine produced concentration-dependent relaxation that was not affected by 1 nmol/L Ang II. In contrast, relaxation to acetylcholine in arteries from CuZnSOD+/- mice was markedly and selectively attenuated after incubation with 1 nmol/L Ang II (eg, 100 micromol/L acetylcholine produced 93+/-6% and 44+/-15% relaxation in vehicle- and Ang II-treated arteries, respectively). A higher concentration of Ang II (10 nmol/L) selectively impaired relaxation to acetylcholine in arteries from control mice (eg, 100 micromol/L acetylcholine produced 96+/-4% and 45+/-7% relaxation in vehicle- and Ang II-treated vessels, respectively). In contrast, 10 nmol/L Ang II had no effect on responses to acetylcholine in carotid arteries from CuZnSOD transgenic mice (or in control mice treated with the superoxide scavenger Tiron [1 mmol/L]). Superoxide levels in control mice were higher in aorta treated with Ang II than with vehicle and were markedly reduced in CuZnSOD transgenic mice. These findings provide the first direct evidence that CuZnSOD limits Ang II-mediated impairment of endothelial function and that loss of 1 copy of the CuZnSOD gene is sufficient to enhance Ang II-induced vascular dysfunction.
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Affiliation(s)
- Sean P Didion
- Department of Internal Medicine, Cardiovascular Center, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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38
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Ago T, Kitazono T, Kuroda J, Kumai Y, Kamouchi M, Ooboshi H, Wakisaka M, Kawahara T, Rokutan K, Ibayashi S, Iida M. NAD(P)H Oxidases in Rat Basilar Arterial Endothelial Cells. Stroke 2005; 36:1040-6. [PMID: 15845888 DOI: 10.1161/01.str.0000163111.05825.0b] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Reactive oxygen species (ROS) may play a critical role in the regulation of vascular tone and development of vascular diseases, such as stroke. NAD(P)H oxidase is a major source of ROS in vascular cells, including endothelial cells. It has been considered that Nox2 and Nox4 are exclusively expressed among Nox homologues in the endothelial cells of noncerebral blood vessels. However, the precise molecular identity of the NAD(P)H oxidase in the endothelial cells of the cerebral arteries is not fully understood. We examined the expression of Nox homologues and their activation mechanism in the endothelial cells of the cerebral arteries.
Methods—
We isolated and cultured basilar artery endothelial cells (BAECs) of Sprague-Dawley rats. Expression of NAD(P)H oxidase was examined by reverse-transcription-polymerase chain reaction (RT-PCR) and immunohistological staining.
Results—
RT-PCR disclosed abundant expression of Nox4 with marginal Nox2 in BAEC. In addition, Nox1 was expressed highly both at mRNA and protein levels in BAECs. Immunohistological staining also showed the prominent expression of Nox1 in the endothelial cells of the basilar artery. With respect to the cytosolic components of NAD(P)H oxidases, BAECs expressed p67
phox
and, to a lesser extent, p47
phox
, Noxo1, and Noxa1. Both NADH and NADPH induced superoxide production of the BAEC membranes. The phagocyte-type cytosolic components, p47
phox
and p67
phox
, significantly enhanced the NADH-induced superoxide production of the BAEC membranes, whereas the components failed to increase the NADPH-induced superoxide production.
Conclusions—
Nox1 is highly expressed in the endothelial cells of the cerebral arteries along with Nox2 and Nox4, and the endothelial NAD(P)H oxidase of the cerebral arteries may have a unique activation mechanism by the phagocyte-type cytosolic components.
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Affiliation(s)
- Tetsuro Ago
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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39
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Zhou X, Ferraris JD, Cai Q, Agarwal A, Burg MB. Increased reactive oxygen species contribute to high NaCl-induced activation of the osmoregulatory transcription factor TonEBP/OREBP. Am J Physiol Renal Physiol 2005; 289:F377-85. [PMID: 15769933 DOI: 10.1152/ajprenal.00463.2004] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The signaling pathways leading to high NaCl-induced activation of the transcription factor tonicity-responsive enhancer binding protein/osmotic response element binding protein (TonEBP/OREBP) remain incompletely understood. High NaCl has been reported to produce oxidative stress. Reactive oxygen species (ROS), which are a component of oxidative stress, contribute to regulation of transcription factors. The present study was undertaken to test whether the high NaCl-induced increase in ROS contributes to tonicity-dependent activation of TonEBP/OREBP. Human embryonic kidney 293 cells were used as a model. We find that raising NaCl increases ROS, including superoxide. N-acetylcysteine (NAC), an antioxidant, and MnTBAP, an inhibitor of superoxide, reduce high NaCl-induced superoxide activity and suppress both high NaCl-induced increase in TonEBP/OREBP transcriptional activity and high NaCl-induced increase in expression of BGT1mRNA, a transcriptional target of TonEBP/OREBP. Catalase, which decomposes hydrogen peroxide, does not have these effects, whether applied exogenously or overexpressed within the cells. Furthermore, NAC and MnTBAP, but not catalase, blunt high NaCl-induced increase in TonEBP/OREBP transactivation. N(G)-monomethyl-l-arginine, a general inhibitor of nitric oxide synthase, has no significant effect on either high NaCl-induced increase in superoxide or TonEBP/OREBP transcriptional activity, suggesting that the effects of ROS do not involve nitric oxide. Ouabain, an inhibitor of Na-K-ATPase, attenuates high NaCl-induced superoxide activity and inhibits TonEBP/OREBP transcriptional activity. We conclude that the high NaCl-induced increase in ROS, including superoxide, contributes to activation of TonEBP/OREBP by increasing its transactivation.
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Affiliation(s)
- Xiaoming Zhou
- Division of Nephrology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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40
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Whiteside CI. Cellular mechanisms and treatment of diabetes vascular complications converge on reactive oxygen species. Curr Hypertens Rep 2005; 7:148-54. [PMID: 15748541 DOI: 10.1007/s11906-005-0090-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
High glucose activates a myriad of signaling and gene expression pathways in non-insulin-dependent target cells causing diabetes complications. One of the earliest responses to high glucose by vascular cells is the generation of reactive oxygen species (ROS) that act directly on intracellular proteins and DNA, or indirectly as second messengers, transforming these cells into disease phenotypes. ROS are produced by mitochondria and/or NADPH oxidase in all target cells exposed to high glucose studied to date. Reports using cell cultures and diabetic animal models indicate that inhibition of ROS generation prevents the amplification of signaling and gene expression that are implicated in vascular complications. These models convincingly demonstrate that maneuvers preventing ROS production attenuate or completely abrogate early micro- and macrovascular end-organ damage of diabetes, including nephropathy, retinopathy, and large-vessel atherosclerosis. Attention now turns to the development of more effective antioxidants that could be used in clinical trials in the prevention and treatment of diabetes complications.
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Affiliation(s)
- Catharine I Whiteside
- Department of Medicine, University of Toronto, 1 King's College Circle, Room 2113, Toronto, ON M5S 1A8, Canada.
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41
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Didion SP, Lynch CM, Baumbach GL, Faraci FM. Impaired endothelium-dependent responses and enhanced influence of Rho-kinase in cerebral arterioles in type II diabetes. Stroke 2005; 36:342-7. [PMID: 15637328 DOI: 10.1161/01.str.0000152952.42730.92] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Although the incidence of type II diabetes is increasing, very little is known regarding vascular responses in the cerebral circulation in this disease. The goals of this study were to examine the role of superoxide in impaired endothelium-dependent responses and to examine the influence of Rho-kinase on vascular tone in the cerebral microcirculation in type II diabetes. METHODS Diameter of cerebral arterioles (29+/-1 microm; mean+/-SE) was measured in vivo using a cranial window in anesthetized db/db and control mice. RESULTS Dilatation of cerebral arterioles in response to acetylcholine (ACh; 1 and 10 micromol/L), but not to nitroprusside, was markedly reduced in db/db mice (eg, 10 micromol/L ACh produced 29+/-1% and 9+/-1% in control and db/db mice, respectively). Superoxide levels were increased (P<0.05) in cerebral arterioles from db/db mice (n=6) compared with controls (n=6). Vasodilatation to ACh in db/db mice was restored to normal by polyethylene glycol-superoxide dismutase (100 U/mL). Y-27632 (1 to 100 micromol/L; a Rho-kinase inhibitor) produced modest vasodilatation in control mice but much greater responses in db/db mice. N(G)-nitro-L-arginine (100 micromol/L; an inhibitor of NO synthase) significantly enhanced Y-27632-induced dilatation in control mice to similar levels as observed in db/db mice. CONCLUSIONS These findings provide the first evidence for superoxide-mediated impairment of endothelium-dependent responses of cerebral vessels in any model of type II diabetes. In addition, the influence of Rho-kinase on resting tone appears to be selectively enhanced in the cerebral microcirculation in this genetic model of type II diabetes.
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Affiliation(s)
- Sean P Didion
- Department of Internal Medicine, University of Iowa Carver College of Medicine Iowa City, IA 52242, USA.
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42
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Didion SP, Faraci FM. Ceramide-Induced Impairment of Endothelial Function Is Prevented by CuZn Superoxide Dismutase Overexpression. Arterioscler Thromb Vasc Biol 2005; 25:90-5. [PMID: 15528474 DOI: 10.1161/01.atv.0000149868.74075.5d] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Ceramide is an important intracellular second messenger that may also increase superoxide. The goal of this study was to determine whether overexpression of CuZn superoxide dismutase (SOD) protects against ceramide-induced increases in vascular superoxide and endothelial dysfunction.
Methods and Results—
Carotid arteries from CuZnSOD-transgenic (CuZnSOD-Tg) and nontransgenic littermates were examined in vitro. Immunohistochemistry confirmed that CuZnSOD protein was greater in carotid artery from CuZnSOD-Tg compared with nontransgenic mice. Ceramide (
N
-acetyl-
d
-sphingosine; 1 and 10 μmol/L) produced concentration-dependent impairment (
P
<0.05) of vasorelaxation in response to the endothelium-dependent agonist acetylcholine (ACh) in nontransgenic mice. For example, 100 μmol/L ACh relaxed arteries from nontransgenic mice by 96±4% and 52±5% in the presence of vehicle and 10 μmol/L ceramide, respectively. In contrast, ceramide (1 or 10 μmol/L) had no effect (
P
>0.05) on responses of carotid artery to ACh in CuZnSOD-Tg mice. Ceramide had no effect on nitroprusside- or papaverine-induced relaxation in CuZnSOD-Tg or nontransgenic mice. Ceramide increased superoxide in arteries from nontransgenic vessels, and this effect was prevented by polyethyleneglycol-SOD (50 U/mL) or overexpression of CuZnSOD.
Conclusions—
These results suggest that ceramide-induced increases in superoxide impair endothelium-dependent relaxation, and that select overexpression of the CuZn isoform of SOD prevents ceramide-induced oxidative stress in vessels.
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Affiliation(s)
- Sean P Didion
- Department of Internal Medicine, 2000 Medical Laboratories, Cardiovascular Center, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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43
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Kazama K, Anrather J, Zhou P, Girouard H, Frys K, Milner TA, Iadecola C. Angiotensin II impairs neurovascular coupling in neocortex through NADPH oxidase-derived radicals. Circ Res 2004; 95:1019-26. [PMID: 15499027 DOI: 10.1161/01.res.0000148637.85595.c5] [Citation(s) in RCA: 194] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Angiotensin II (Ang II) exerts detrimental effects on cerebral circulation, the mechanisms of which have not been elucidated. In particular, Ang II impairs the increase in cerebral blood flow (CBF) produced by neural activity, a critical mechanism that matches substrate delivery with energy demands in brain. We investigated whether Ang II exerts its deleterious actions by activating Ang II type 1 (AT1) receptors on cerebral blood vessels and producing reactive oxygen species (ROS) through NADPH oxidase. Somatosensory cortex CBF was monitored in anesthetized mice by laser-Doppler flowmetry. Ang II (0.25 microg/kg per minute IV) attenuated the CBF increase produced by mechanical stimulation of the vibrissae. The effect was blocked by the AT1 antagonist losartan and by ROS scavenger superoxide dismutase or tiron and was not observed in mice lacking the gp91phox subunit of NADPH oxidase or in wild-type mice treated with the NADPH oxidase peptide inhibitor gp91ds-tat. Ang II increased ROS production in cerebral microvessels, an effect blocked by the ROS scavenger Mn(III)tetrakis (4-benzoic acid) porphyrin and by the NADPH oxidase assembly inhibitor apocynin. Ang II did not increase ROS production in gp91-null mice. Double-label immunoelectron microscopy demonstrated that AT1 and gp91phox immunoreactivities were present in endothelium and adventitia of neocortical arterioles. Collectively, these findings suggest that Ang II impairs functional hyperemia by activating AT1 receptors and inducing ROS production via a gp91phox containing NADPH oxidase. The data provide the mechanistic basis for the cerebrovascular dysregulation induced by Ang II and suggest novel therapeutic strategies to counteract the effects of hypertension on the brain.
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MESH Headings
- 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt/pharmacology
- Acetophenones/pharmacology
- Amino Acid Sequence
- Angiotensin II/toxicity
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Animals
- Arterioles/drug effects
- Arterioles/metabolism
- Cerebrovascular Circulation/drug effects
- Cytochromes b/deficiency
- Cytochromes b/genetics
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Free Radical Scavengers/pharmacology
- Free Radicals
- Glycoproteins/pharmacology
- Hypercapnia/physiopathology
- Hyperemia/physiopathology
- Hypertension/chemically induced
- Laser-Doppler Flowmetry
- Losartan/pharmacology
- Male
- Membrane Glycoproteins/physiology
- Metalloporphyrins/pharmacology
- Mice
- Mice, Inbred C57BL
- Molecular Sequence Data
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- NADPH Oxidase 2
- NADPH Oxidases/physiology
- Nitric Oxide Donors/pharmacology
- Polyethylene Glycols/pharmacology
- Rats
- Rats, Sprague-Dawley
- Reactive Oxygen Species/metabolism
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 1/physiology
- S-Nitroso-N-Acetylpenicillamine/pharmacology
- Somatosensory Cortex/blood supply
- Somatosensory Cortex/drug effects
- Somatosensory Cortex/enzymology
- Superoxide Dismutase/pharmacology
- Vibrissae/physiology
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Affiliation(s)
- Ken Kazama
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY, USA
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44
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Abstract
MnSOD is the only mammalian isoform of SOD that is necessary for life. MnSOD(-/-) mice die soon after birth, and MnSOD(+/-) mice are more susceptible to oxidative stress than wild-type (WT) mice. In this study, we examined vasomotor function responses in aortas of MnSOD(+/-) mice under normal conditions and during oxidative stress. Under normal conditions, contractions to serotonin (5-HT) and prostaglandin F2alpha (PGF2alpha), relaxation to ACh, and superoxide levels were similar in aortas of WT and MnSOD(+/-) mice. The mitochondrial inhibitor antimycin A reduced contraction to PGF2alpha and impaired relaxation to ACh to a similar extent in aortas of WT and MnSOD(+/-) mice. The Cu/ZnSOD and extracellular SOD inhibitor diethyldithiocarbamate (DDC) paradoxically enhanced contraction to 5-HT and superoxide more in aortas of WT mice than in MnSOD(+/-) mice. DDC impaired relaxation to ACh and reduced total SOD activity similarly in aortas of both genotypes. Tiron, a scavenger of superoxide, normalized contraction to 5-HT, relaxation to ACh, and superoxide levels in DDC-treated aortas of WT and MnSOD(+/-) mice. Hypoxia, which reportedly increases superoxide, reduced contractions to 5-HT and PGF2alpha similarly in aortas of WT and MnSOD(+/-) mice. The vasomotor response to acute hypoxia was similar in both genotypes. In summary, under normal conditions and during acute oxidative stress, vasomotor function is similar in WT and MnSOD(+/-) mice. We speculate that decreased mitochondrial superoxide production may preserve nitric oxide bioavailability during oxidative stress.
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Affiliation(s)
- Jon J Andresen
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242, USA
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Lavoie JL, Bianco RA, Sakai K, Keen HL, Ryan MJ, Sigmund CD. Transgenic mice for studies of the renin-angiotensin system in hypertension. ACTA ACUST UNITED AC 2004; 181:571-7. [PMID: 15283772 DOI: 10.1111/j.1365-201x.2004.01332.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Hypertension is a polygenic and multi-factorial disorder that is extremely prevalent in western societies, and thus has received a great deal of attention by the research community. The renin-angiotensin system has a strong impact on the control of blood pressure both in the short- and long-term, making it one of the most extensively studied physiological systems. Nevertheless, despite decades of research, the specific mechanisms implicated in its action on blood pressure and electrolyte balance, as well as its integration with other cardiovascular pathways remains incomplete. The production of transgenic models either over-expressing or knocking-out specific components of the renin-angiotensin system has given us a better understanding of its role in the pathogenesis of hypertension. Moreover, our attention has recently been refocused on local tissue renin-angiotensin systems and their physiological effect on blood pressure and end-organ damage. Herein, we will review studies using genetic manipulation of animals to determine the role of the endocrine and tissue renin-angiotensin system in hypertension. We will also discuss some untraditional approaches to target the renin-angiotensin system in the kidney.
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Affiliation(s)
- J L Lavoie
- Department of Internal Medicine and Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, USA
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Ryan MJ, Didion SP, Mathur S, Faraci FM, Sigmund CD. Angiotensin II–Induced Vascular Dysfunction Is Mediated by the AT1AReceptor in Mice. Hypertension 2004; 43:1074-9. [PMID: 15007032 DOI: 10.1161/01.hyp.0000123074.89717.3d] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many of the actions of angiotensin II (Ang II) are mediated by angiotensin type 1 receptors (AT1), of which there are 2 pharmacologically indistinguishable subtypes (AT1A and AT1B). The purpose of this study was to evaluate the effect of an AT1A homozygous deletion (AT1A-/-) on vascular reactivity. AT1A-/- mice and control littermates (AT1A+/+) were infused with vehicle (saline) or Ang II (1000 ng x kg(-1) x min(-1)) for 7 days by osmotic pumps. Systolic pressure was increased in AT1A+/+ mice (Delta45+/-8 mm Hg, P<0.0001) but unchanged in AT1A-/- mice (Delta5+/-3 mm Hg, P>0.13) on day 7. The carotid artery response to the vasodilators acetylcholine (ACh), nitroprusside, and papaverine and to the vasoconstrictors phenylephrine, U46619, 5-hydroxytryptamine (5-HT), and KCl were not different between vehicle-infused AT1A+/+ and AT1A-/- animals. Carotid relaxation to ACh was impaired and contraction to 5-HT was increased in Ang II-infused AT1A+/+ mice. Ang II did not affect carotid responses in AT1A-/- mice. Superoxide, measured by lucigenin (5 micromol/L), and hydroethidine staining were not different between AT1A+/+ and AT1A-/- mice after vehicle or Ang II infusion, suggesting that it was not contributing to the altered ACh and 5-HT responses. The Rho-kinase inhibitor Y-27632 (1 micromol/L) attenuated the 5-HT response in both vehicle- and Ang II-infused AT1A+/+ mice. Moreover, concentration-dependent relaxation to Y-27632 and RhoA protein expression were not different in vehicle- or Ang II-infused AT1A+/+. These data demonstrate that the AT1A receptor is required for Ang II-induced changes in carotid artery function.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Acetylcholine/pharmacology
- Amides/pharmacology
- Angiotensin II/administration & dosage
- Angiotensin II/toxicity
- Animals
- Aorta/metabolism
- Carotid Arteries/drug effects
- Infusion Pumps, Implantable
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nitric Oxide/physiology
- Nitroprusside/pharmacology
- Papaverine/pharmacology
- Phenylephrine/pharmacology
- Potassium Chloride/pharmacology
- Pyridines/pharmacology
- Receptor, Angiotensin, Type 1/biosynthesis
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/physiology
- Receptor, Angiotensin, Type 2/biosynthesis
- Receptor, Angiotensin, Type 2/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Deletion
- Serotonin/pharmacology
- Superoxides/metabolism
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
- Vasoconstrictor Agents/pharmacology
- Vasodilator Agents/pharmacology
- rhoA GTP-Binding Protein
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Affiliation(s)
- Michael J Ryan
- Department of Internal Medicine, Cardiovascular Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City 52242, USA.
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Ryan MJ, Didion SP, Mathur S, Faraci FM, Sigmund CD. PPAR(gamma) agonist rosiglitazone improves vascular function and lowers blood pressure in hypertensive transgenic mice. Hypertension 2004; 43:661-6. [PMID: 14744930 DOI: 10.1161/01.hyp.0000116303.71408.c2] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The peroxisome proliferator activated receptor (PPARgamma) agonist rosiglitazone has been reported to yield cardiovascular benefits in patients by a mechanism that is not completely understood. We tested whether oral rosiglitazone (25 mg/kg per day, 21 days) treatment improves blood pressure and vascular function in a transgenic mouse expressing both human renin and human angiotensinogen transgenes (R(+)A(+)). Rosiglitazone decreased systolic (138+/-5 versus 128+/-5 mm Hg) and mean blood pressure (145+/-5 versus 126+/-7 mm Hg) of R(+)A(+) mice as measured by tail-cuff and indwelling carotid catheters, respectively. Relaxation of carotid arteries to acetylcholine and authentic nitric oxide, but not papaverine, was impaired in R(+)A(+) mice when compared with littermate controls (RA(-)). There were no effects of rosiglitazone on RA(-) mice; however, relaxation to acetylcholine (49+/-10 versus 82+/-9% at 100 micromol/L) and nitric oxide (51+/-11 versus 72+/-6% at 10 micromol/L) was significantly improved in treated R(+)A(+) mice. Rosiglitazone treatment of R(+)A(+) mice did not alter the expression of genes, including endothelial nitric oxide synthase (eNOS), angiotensin 1 receptors, and preproendothelin-1, nor did it alter the levels of eNOS or soluble guanylyl cyclase protein. In separate studies, carotid arteries from R(+)A(+) and RA(-) mice relaxed in a concentration-dependent manner to rosiglitazone, suggesting possible PPARgamma-independent effects in the vasculature. This response was not inhibited with the nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester (200 micromol/L) or the PPARgamma antagonist bisphenol A diglycidyl ether; 4,4'-isopropylidenediphenol diglycidyl ether (100 micromol/L). These data suggest that in addition to potential genomic regulation caused by PPARgamma activation, the direct effect of rosiglitazone in blood vessels may contribute to the improved blood pressure and vessel function.
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Affiliation(s)
- Michael J Ryan
- Ph.D. Professor, Department of Internal Medicine, 3181 MERF, University of Iowa, Department of Internal Medicine Iowa City, IA 52242, USA.
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Haque MZ, Majid DSA. Assessment of renal functional phenotype in mice lacking gp91PHOX subunit of NAD(P)H oxidase. Hypertension 2004; 43:335-40. [PMID: 14718366 DOI: 10.1161/01.hyp.0000111137.15873.4a] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To determine the role of endogenous superoxide (O2-) in the kidney, we assessed renal hemodynamics and excretory function in gp91(PHOX) (a NAD(P)H oxidase subunit) gene knockout (KO) mice and compared these findings with those of wild-type (WT) strain C57BL/6 mice. Renal blood flow (RBF) and glomerular filtration rate (GFR) were determined by PAH and inulin clearances respectively in anesthetized mice (n=8 in each group). There were higher baseline RBF (4.3+/-0.4 versus 2.5+/-0.2 mL/min per gram; P<0.002) and lower renal vascular resistance (RVR) (16+/-1.4 versus 29+/-2.3 mm Hg/mL/min per gram; P<0.0001) in KO compared with WT without a significant difference in mean arterial pressure (MAP) (67+/-2 versus 71+/-2 mm Hg) and GFR (0.66+/-0.09 versus 0.73+/-0.05 mL/min per gram) between the strains. Intravenous infusion of angiotensin II (Ang II) (2 ng/min per gram of body weight) for 30 minutes caused a lesser degree of decreases in RBF (-8% versus -33%) and of increases in RVR (+73% versus +173%) in KO compared with WT. GFR was increased (43%) in KO but not in WT during Ang II infusion. Urinary excretion of nitrate/nitrite was higher in conscious KO (n=5) than in WT (n=5), indicating an increase in nitric oxide bioavailability that could be the cause of high RBF and low RVR in KO. These data indicate that gp91(PHOX), a subunit of NAD(P)H oxidase, plays a regulatory role in the maintenance of renal vascular tone. These results also suggest that the mechanism of Ang II-mediated renal vascular action involves concomitant generation of O2-.
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Affiliation(s)
- Mohammed Z Haque
- Department of Physiology, Tulane University Health Sciences Center, New Orleans, La 70112, USA
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Didion SP, Faraci FM. Angiotensin II produces superoxide-mediated impairment of endothelial function in cerebral arterioles. Stroke 2003; 34:2038-42. [PMID: 12829858 DOI: 10.1161/01.str.0000081225.46324.aa] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Angiotensin II (Ang II) produces oxidative stress in vascular cells in culture and in extracranial conduit arteries. The goal of this study was to examine the hypothesis that Ang II produces superoxide-mediated impairment of endothelial function in cerebral microvessels. METHODS Diameter of cerebral arterioles (baseline diameter=104+/-3 microm) was measured with the use of a closed cranial window in anesthetized rabbits. Topical application of Ang II was used to avoid effects on arterial pressure. RESULTS Ang II (0.1 to 1 micromol/L for 2 hours) had no effect on baseline diameter (change in diameter of -3+/-2% in response to 1 micromol/L Ang II) but produced concentration-dependent inhibition of vasodilatation to the endothelium-dependent agonist bradykinin. For example, 1 micromol/L Ang II inhibited responses to 1 nmol/L bradykinin by almost 80%. These inhibitory effects of Ang II were prevented by the superoxide scavenger 4,5-dihydroxy-1,3-benzene-disulfonic acid (Tiron; 10 mmol/L) or diphenylene iodonium (DPI; 3 micromol/L), an inhibitor of NAD(P)H oxidase. Ang II did not inhibit vasodilatation in response to nitroprusside, an endothelium-independent vasodilator. CONCLUSIONS These findings are the first evidence that local Ang II produces superoxide-mediated vascular dysfunction in cerebral microvessels. The results with DPI suggest that the source of superoxide may be an NAD(P)H oxidase.
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Affiliation(s)
- Sean P Didion
- Department of Internal Medicine, Cardiovascular Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242-1081, USA
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Lassègue B, Clempus RE. Vascular NAD(P)H oxidases: specific features, expression, and regulation. Am J Physiol Regul Integr Comp Physiol 2003; 285:R277-97. [PMID: 12855411 DOI: 10.1152/ajpregu.00758.2002] [Citation(s) in RCA: 644] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The importance of reactive oxygen species (ROS) in vascular physiology and pathology is becoming increasingly evident. All cell types in the vascular wall produce ROS derived from superoxide-generating protein complexes similar to the leukocyte NADPH oxidase. Specific features of the vascular enzymes include constitutive and inducible activities, substrate specificity, and intracellular superoxide production. Most phagocyte enzyme subunits are found in vascular cells, including the catalytic gp91phox (aka, nox2), which was the earliest member of the newly discovered nox family. However, smooth muscle frequently expresses nox1 rather than gp91phox, and nox4 is additionally present in all cell types. In cell culture, agonists increase ROS production by activating multiple signals, including protein kinase C and Rac, and by upregulating oxidase subunits. The oxidases are also upregulated in vascular disease and are involved in the development of atherosclerosis and a significant part of angiotensin II-induced hypertension, possibly via nox1 and nox4. Likewise, enhanced vascular oxidase activity is associated with diabetes. Therefore, members of this enzyme family appear to be important in vascular biology and disease and constitute promising targets for future therapeutic interventions.
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