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Abstract
The cerebral microcirculation undergoes dynamic changes in parallel with the development of neurons, glia, and their energy metabolism throughout gestation and postnatally. Cerebral blood flow (CBF), oxygen consumption, and glucose consumption are as low as 20% of adult levels in humans born prematurely but eventually exceed adult levels at ages 3 to 11 years, which coincide with the period of continued brain growth, synapse formation, synapse pruning, and myelination. Neurovascular coupling to sensory activation is present but attenuated at birth. By 2 postnatal months, the increase in CBF often is disproportionately smaller than the increase in oxygen consumption, in contrast to the relative hyperemia seen in adults. Vascular smooth muscle myogenic tone increases in parallel with developmental increases in arterial pressure. CBF autoregulatory response to increased arterial pressure is intact at birth but has a more limited range with arterial hypotension. Hypoxia-induced vasodilation in preterm fetal sheep with low oxygen consumption does not sustain cerebral oxygen transport, but the response becomes better developed for sustaining oxygen transport by term. Nitric oxide tonically inhibits vasomotor tone, and glutamate receptor activation can evoke its release in lambs and piglets. In piglets, astrocyte-derived carbon monoxide plays a central role in vasodilation evoked by glutamate, ADP, and seizures, and prostanoids play a large role in endothelial-dependent and hypercapnic vasodilation. Overall, homeostatic mechanisms of CBF regulation in response to arterial pressure, neuronal activity, carbon dioxide, and oxygenation are present at birth but continue to develop postnatally as neurovascular signaling pathways are dynamically altered and integrated. © 2021 American Physiological Society. Compr Physiol 11:1-62, 2021.
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Takaishi K, Kinoshita H, Kawashima S, Kawahito S. Human Vascular Smooth Muscle Function and Oxidative Stress Induced by NADPH Oxidase with the Clinical Implications. Cells 2021; 10:cells10081947. [PMID: 34440716 PMCID: PMC8393371 DOI: 10.3390/cells10081947] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 01/05/2023] Open
Abstract
Among reactive oxygen species, superoxide mediates the critical vascular redox signaling, resulting in the regulation of the human cardiovascular system. The reduced form of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase, NOX) is the source of superoxide and relates to the crucial intracellular pathology and physiology of vascular smooth muscle cells, including contraction, proliferation, apoptosis, and inflammatory response. Human vascular smooth muscle cells express NOX1, 2, 4, and 5 in physiological and pathological conditions, and those enzymes play roles in most cardiovascular disorders caused by hypertension, diabetes, inflammation, and arteriosclerosis. Various physiologically active substances, including angiotensin II, stimulate NOX via the cytosolic subunits’ translocation toward the vascular smooth muscle cell membrane. As we have shown, some pathological stimuli such as high glucose augment the enzymatic activity mediated by the phosphatidylinositol 3-kinase-Akt pathway, resulting in the membrane translocation of cytosolic subunits of NOXs. This review highlights and details the roles of human vascular smooth muscle NOXs in the pathophysiology and clinical aspects. The regulation of the enzyme expressed in the vascular smooth muscle cells may lead to the prevention and treatment of human cardiovascular diseases.
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Affiliation(s)
- Kazumi Takaishi
- Department of Dental Anesthesiology, Graduate School of Biomedical Sciences, Tokushima University, 3-18-15, Kuramoto, Tokushima 770-8504, Japan; (K.T.); (S.K.)
| | - Hiroyuki Kinoshita
- Department of Anesthesiology, Graduate School of Biomedical Sciences, Tokushima University, 3-18-15, Kuramoto, Tokushima 770-8504, Japan
- Department of Anesthesiology and Intensive Care, School of Medicine, Hamamatsu University, 1-20-1, Handayama, Hamamatsu City 431-3192, Japan;
- Correspondence: ; Tel.: +81-53-436-1251
| | - Shingo Kawashima
- Department of Anesthesiology and Intensive Care, School of Medicine, Hamamatsu University, 1-20-1, Handayama, Hamamatsu City 431-3192, Japan;
| | - Shinji Kawahito
- Department of Dental Anesthesiology, Graduate School of Biomedical Sciences, Tokushima University, 3-18-15, Kuramoto, Tokushima 770-8504, Japan; (K.T.); (S.K.)
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Yan S, Resta TC, Jernigan NL. Vasoconstrictor Mechanisms in Chronic Hypoxia-Induced Pulmonary Hypertension: Role of Oxidant Signaling. Antioxidants (Basel) 2020; 9:E999. [PMID: 33076504 PMCID: PMC7602539 DOI: 10.3390/antiox9100999] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 02/06/2023] Open
Abstract
Elevated resistance of pulmonary circulation after chronic hypoxia exposure leads to pulmonary hypertension. Contributing to this pathological process is enhanced pulmonary vasoconstriction through both calcium-dependent and calcium sensitization mechanisms. Reactive oxygen species (ROS), as a result of increased enzymatic production and/or decreased scavenging, participate in augmentation of pulmonary arterial constriction by potentiating calcium influx as well as activation of myofilament sensitization, therefore mediating the development of pulmonary hypertension. Here, we review the effects of chronic hypoxia on sources of ROS within the pulmonary vasculature including NADPH oxidases, mitochondria, uncoupled endothelial nitric oxide synthase, xanthine oxidase, monoamine oxidases and dysfunctional superoxide dismutases. We also summarize the ROS-induced functional alterations of various Ca2+ and K+ channels involved in regulating Ca2+ influx, and of Rho kinase that is responsible for myofilament Ca2+ sensitivity. A variety of antioxidants have been shown to have beneficial therapeutic effects in animal models of pulmonary hypertension, supporting the role of ROS in the development of pulmonary hypertension. A better understanding of the mechanisms by which ROS enhance vasoconstriction will be useful in evaluating the efficacy of antioxidants for the treatment of pulmonary hypertension.
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Affiliation(s)
| | | | - Nikki L. Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; (S.Y.); (T.C.R.)
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Whidden MA, Basgut B, Kirichenko N, Erdos B, Tümer N. Altered potassium ATP channel signaling in mesenteric arteries of old high salt-fed rats. J Exerc Nutrition Biochem 2016; 20:58-64. [PMID: 27508155 PMCID: PMC4977904 DOI: 10.20463/jenb.2016.06.20.2.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 04/27/2016] [Accepted: 04/27/2016] [Indexed: 11/30/2022] Open
Abstract
[Purpose] Both aging and the consumption of a high salt diet are associated with clear changes in the vascular system that can lead to the development of cardiovascular disease; however the mechanisms are not clearly understood. Therefore, we examined whether aging and the consumption of excess salt alters the function of potassium ATP-dependent channel signaling in mesenteric arteries [Methods] Young (7 months) and old (29 months) Fischer 344 x Brown Norway rats were fed a control or a high salt diet (8% NaCl) for 12 days and mesenteric arteries were utilized for vascular reactivity measurements. [Results] Acetylcholine-induced endothelium relaxation was significantly reduced in old arteries (81 ± 4%) when compared with young arteries (92 ± 2%). Pretreatment with the potassium-ATP channel blocker glibenclamide reduced relaxation to acetylcholine in young arteries but did not alter dilation in old arteries. On a high salt diet, endothelium dilation to acetylcholine was significantly reduced in old salt arteries (60 ± 3%) when compared with old control arteries (81 ± 4%). Glibenclamide reduced acetylcholine-induced dilation in young salt arteries but had no effect on old salt arteries. Dilation to cromakalim, a potassium-ATP channel opener, was reduced in old salt arteries when compared with old control arteries. [Conclusion] These findings demonstrate that aging impairs endothelium-dependent relaxation in mesenteric arteries. Furthermore, a high salt diet alters the function of potassium-ATP-dependent channel signaling in old isolated mesenteric arteries and affects the mediation of relaxation stimuli.
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Affiliation(s)
- Melissa A Whidden
- Department of Kinesiology, West Chester University, West Chester USA
| | - Bilgen Basgut
- Department of Pharmacology, Near East University, Northern Cyprus Turkey
| | - Nataliya Kirichenko
- Geriatric Research, Education and Clinical Center, Department of Veterans Affairs Medical Center GainesvilleUSA; Department of Pharmacology and Therapeutics, University of Florida, GainesvilleUSA
| | - Benedek Erdos
- Department of Pharmacology, University of Vermont, Burlington USA
| | - Nihal Tümer
- Geriatric Research, Education and Clinical Center, Department of Veterans Affairs Medical Center GainesvilleUSA; Department of Pharmacology and Therapeutics, University of Florida, GainesvilleUSA
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5
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Basudhar D, Ridnour LA, Cheng R, Kesarwala AH, Heinecke J, Wink DA. Biological signaling by small inorganic molecules. Coord Chem Rev 2016; 306:708-723. [PMID: 26688591 PMCID: PMC4680994 DOI: 10.1016/j.ccr.2015.06.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Small redox active molecules such as reactive nitrogen and oxygen species and hydrogen sulfide have emerged as important biological mediators that are involved in various physiological and pathophysiological processes. Advancement in understanding of cellular mechanisms that tightly regulate both generation and reactivity of these molecules is central to improved management of various disease states including cancer and cardiovascular dysfunction. Imbalance in the production of redox active molecules can lead to damage of critical cellular components such as cell membranes, proteins and DNA and thus may trigger the onset of disease. These small inorganic molecules react independently as well as in a concerted manner to mediate physiological responses. This review provides a general overview of the redox biology of these key molecules, their diverse chemistry relevant to physiological processes and their interrelated nature in cellular signaling.
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Affiliation(s)
- Debashree Basudhar
- Radiation Biology Branch, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Lisa A. Ridnour
- Radiation Biology Branch, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Robert Cheng
- Radiation Biology Branch, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Aparna H. Kesarwala
- Radiation Oncology Branch, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Julie Heinecke
- Radiation Biology Branch, National Cancer Institute, NIH, Bethesda, MD 20892
| | - David A. Wink
- Radiation Biology Branch, National Cancer Institute, NIH, Bethesda, MD 20892
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Bohman LE, Riley J, Milovanova TN, Sanborn MR, Thom SR, Armstead WM. Microparticles Impair Hypotensive Cerebrovasodilation and Cause Hippocampal Neuronal Cell Injury after Traumatic Brain Injury. J Neurotrauma 2015; 33:168-74. [PMID: 26230045 DOI: 10.1089/neu.2015.3885] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Endothelin-1 (ET-1), tissue plasminogen activator (tPA), and extracellular signal-regulated kinases-mitogen activated protein kinase (ERK-MAPK) are mediators of impaired cerebral hemodynamics after fluid percussion brain injury (FPI) in piglets. Microparticles (MPs) are released into the circulation from a variety of cells during stress, are pro-thrombotic and pro-inflammatory, and may be lysed with polyethylene glycol telomere B (PEG-TB). We hypothesized that MPs released after traumatic brain injury impair hypotensive cerebrovasodilation and that PEG-TB protects the vascular response via MP lysis, and we investigated the relationship between MPs, tPA, ET-1, and ERK-MAPK in that process. FPI was induced in piglets equipped with a closed cranial window. Animals received PEG-TB or saline (vehicle) 30-minutes post-injury. Serum and cerebrospinal fluid (CSF) were sampled and pial arteries were measured pre- and post-injury. MPs were quantified by flow cytometry. CSF samples were analyzed with enzyme-linked immunosorbent assay. MP levels, vasodilatory responses, and CSF signaling assays were similar in all animals prior to injury and treatment. After injury, MP levels were elevated in the serum of vehicle but not in PEG-TB-treated animals. Pial artery dilation in response to hypotension was impaired after injury but protected in PEG-TB-treated animals. After injury, CSF levels of tPA, ET-1, and ERK-MAPK were all elevated, but not in PEG-TB-treated animals. PEG-TB-treated animals also showed reduction in neuronal injury in CA1 and CA3 hippocampus, compared with control animals. These results show that serum MP levels are elevated after FPI and lead to impaired hypotensive cerebrovasodilation via over-expression of tPA, ET-1, and ERK-MAPK. Treatment with PEG-TB after injury reduces MP levels and protects hypotensive cerebrovasodilation and limits hippocampal neuronal cell injury.
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Affiliation(s)
- Leif-Erik Bohman
- 1 Department of Neurosurgery, University of Pennsylvania , Philadelphia, Pennsylvania
| | - John Riley
- 2 Department of Anesthesiology and Critical Care, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Tatyana N Milovanova
- 3 Department of Emergency Medicine, University of Pennsylvania , Philadelphia, Pennsylvania.,5 Institute for Environmental Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Matthew R Sanborn
- 1 Department of Neurosurgery, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Stephen R Thom
- 3 Department of Emergency Medicine, University of Pennsylvania , Philadelphia, Pennsylvania.,5 Institute for Environmental Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - William M Armstead
- 2 Department of Anesthesiology and Critical Care, University of Pennsylvania , Philadelphia, Pennsylvania.,4 Department of Pharmacology, University of Pennsylvania , Philadelphia, Pennsylvania
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Reynolds CA, Schafer S, Pirooz R, Marinica A, Chbib A, Bedford C, Fronczak M, Rafols JA, Kuhn D, Kreipke CW. Differential effects of endothelin receptor A and B antagonism on behavioral outcome following traumatic brain injury. Neurol Res 2013; 33:197-200. [DOI: 10.1179/016164111x12881719352499] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Kreipke CW, Rafols JA, Reynolds CA, Schafer S, Marinica A, Bedford C, Fronczak M, Kuhn D, Armstead WM. Retracted Article: Clazosentan, a novel endothelin A antagonist, improves cerebral blood flow and behavior after traumatic brain injury. Neurol Res 2013; 33:208-13. [DOI: 10.1179/016164111x12881719352570] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Maegele M, Wafaisade A, Peiniger S, Braun M. The role of endothelin and endothelin antagonists in traumatic brain injury: a review of the literature. Neurol Res 2012; 33:119-26. [PMID: 21801586 DOI: 10.1179/016164111x12881719352093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES To date, there is increasing evidence for the role of endothelins in the pathophysiological development of cerebral vasospasms associated with a variety of neurological diseases, e.g., stroke and subarachnoid hemorrhage. In contrast, only little is known regarding the role of endothelins in impaired cerebral hemodynamics after traumatic brain injury. Therapeutic work in blocking the endothelin system has led to the discovery of a number of antagonists potentially useful in restoring cerebral blood flow after traumatic brain injury, potentially reducing the detrimental effects of secondary brain injury. Therefore, the present work provides an overview of background topics such as structures and biosynthesis of endothelins, different types as well as potential mechanisms and sites of action. In addition, the role of age for the effects of endothelins on cerebral hemodynamics after traumatic brain injury is discussed. RESULTS Description of data supporting the role of the endothelins play in a host of neurological deficits. CONCLUSIONS Endothelin antagonists may be effective as novel treatments for various neuropathologies.
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Affiliation(s)
- Marc Maegele
- Department of Trauma and Orthopedic Surgery, University of Witten/Herdecke, Cologne-Merheim Medical Center, Germany.
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Brain cellular localization of endothelin receptors A and B in a rodent model of diffuse traumatic brain injury. Neuroscience 2010; 168:820-30. [DOI: 10.1016/j.neuroscience.2010.01.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Revised: 12/23/2009] [Accepted: 01/11/2010] [Indexed: 01/23/2023]
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Choi A, Choi JS, Yoon YJ, Kim KA, Joo CK. KR-31378, a potassium-channel opener, induces the protection of retinal ganglion cells in rat retinal ischemic models. J Pharmacol Sci 2009; 109:511-7. [PMID: 19372634 DOI: 10.1254/jphs.fp0072067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
KR-31378 is a newly developed K(ATP)-channel opener. To investigate the ability of KR-31378 to protect retinal ganglion cells (RGC), experiments were conducted using two retinal ischemia models. Retinal ischemia was induced by transient high intraocular pressure (IOP) for acute ischemia and by three episcleral vein occlusion for chronic retinal ischemia. KR-31378 was injected intraperitoneally and administered orally in the acute and chronic ischemia models, respectively. Under the condition of chronic ischemia, RGC density in the KR-31378-treated group was statistically higher than that in the non-treated group, and IOP was reduced. In the acute retinal ischemia model, 90% of RGC were degenerated after one week in non-treated retina, but, RGC in KR-31378-treated retina were protected from ischemic damage in a dose-dependent manner and showed inhibited glial fibrillary acidic protein (GFAP) expression. Furthermore, the KR-31378 protective effect was inhibited by glibenclamide treatment in acute ischemia. These findings indicate that systemic KR-31378 treatment may protect against ischemic injury-induced ganglion cell loss in glaucoma.
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Affiliation(s)
- Anho Choi
- Department of Ophthalmology and Visual Science, College of Medicine and Korean Eye and Gene Bank Related to Blindness, The Catholic University of Korea, Seoul, Korea
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Zhu Y, Zhang S, Xie W, Li Q, Zhou Y, Wang H. Iptakalim inhibited endothelin-1-induced proliferation of human pulmonary arterial smooth muscle cells through the activation of KATP channel. Vascul Pharmacol 2008; 48:92-9. [DOI: 10.1016/j.vph.2008.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2007] [Revised: 12/15/2007] [Accepted: 01/04/2008] [Indexed: 11/16/2022]
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Tiwari R, Singh V, Barthwal M. Macrophages: An elusive yet emerging therapeutic target of atherosclerosis. Med Res Rev 2008; 28:483-544. [DOI: 10.1002/med.20118] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Tang C, Wu AH, Xue HL, Wang YJ. Tanshinone IIA inhibits endothelin-1 production in TNF-alpha-induced brain microvascular endothelial cells through suppression of endothelin-converting enzyme-1 synthesis. Acta Pharmacol Sin 2007; 28:1116-22. [PMID: 17640471 DOI: 10.1111/j.1745-7254.2007.00598.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIM To investigate the effects of tanshinone IIA (Tan IIA) on the regulation of the production of endothelin (ET)-1 (including large ET-1), mRNA levels of ET-1, endothelin-converting enzyme-1 (ECE-1), endothelin-A receptor (ETA) and endothelin-B receptor (ETB) induced by TNF-alpha in rat brain microvascular endothelial cells (BMVEC). METHODS The ET-1 release (including large ET-1) into the culture medium was determined by enzyme immunoassay. The levels of ET-1, ECE-1, ETA, and ETB mRNA were measured by RT-PCR. Endothelin receptor binding was also tested. RESULTS The induction of ET-1 release by TNF-alpha from cultured BMVEC was dose-dependently reduced by Tan IIA, but large ET-1 levels progressively increased in response to Tan IIA; the mRNA expression of ET-1 was unaffected. Tan IIA also caused a decrease in ETA receptor mRNA and ECE-1 expression in a dose-dependent manner. Endothelin receptor binding was unaltered in BMVEC stimulated with TNF-alpha alone or a combination of TNF-alpha and Tan IIA. CONCLUSION These findings suggest that Tan IIA may inhibit ET-1 production in TNF-alpha-induced BMVEC through the suppression of ECE-1 synthesis.
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Affiliation(s)
- Chao Tang
- Department of Neurosurgery, the First Affiliated Hospital, China Medical University, Shenyang, China
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Maier B, Lehnert M, Laurer HL, Marzi I. Biphasic elevation in cerebrospinal fluid and plasma concentrations of endothelin 1 after traumatic brain injury in human patients. Shock 2007; 27:610-4. [PMID: 17505299 DOI: 10.1097/shk.0b013e31802f9eaf] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Severe traumatic brain injury (TBI) is characterized by a high mortality and poor outcome. The pathomechanisms involved are cytokine-mediated proinflammatory and anti-inflammatory reactions and significant cerebral microcirculatory disorders. The role of endothelin 1 (ET-1), a very potent vasoconstrictive peptide, in the deterioration of cerebral perfusion after trauma is still unclear. The presented study investigated the changes in ET-1 in the cerebrospinal fluid (CSF) and plasma after TBI in humans, with special regard to the presence of subarachnoid hemorrhage (SAH) and clinical outcome. Twenty patients with TBI were consecutively enrolled into the study, 10 patients without SAH (TBI group) and 10 patients with SAH (TBI-H group). Paired samples of plasma and CSF were collected for 10 days after trauma. Analysis of the ET-1 concentrations showed that TBI is associated with initially increased ET-1 values in plasma (TBI, day 1; TBI-H, days 2-3) and significantly increased (P < 0.05, vs. control) CSF concentrations (TBI, days 1-2; TBI-H, days 1-3) in the first days after trauma. In the further time course, ET-1 values declined in both groups, reaching reference values in plasma. The CSF values remained significantly (P < 0.05 vs. control) elevated. Both groups showed a second peak on the beginning of the second week after trauma in plasma and CSF. Whereas plasma concentrations failed to reach significance, CSF values showed a significant peak on day 7 in both groups. The TBI-H patients had significantly (P < 0.05) higher values in the secondary peak compared with patients of the TBI group. The kinetics of traumatic SAH-dependent ET-1 needs to be assessed in further investigations.
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Affiliation(s)
- Bernd Maier
- Department of Trauma, Hand, and Reconstructive Surgery, Medical School of the Johann Wolfgang Goethe University, D-60590 Frankfurt/Main, Germany.
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Armstead WM, Cines DB, Al-Roof Higazi A. Altered NO function contributes to impairment of uPA and tPA cerebrovasodilation after brain injury. J Neurotrauma 2004; 21:1204-11. [PMID: 15453990 DOI: 10.1089/neu.2004.21.1204] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Urokinase (uPA) and tissue plasminogen activator (tPA) are serine proteases implicated in fibrinolysis, but their role in the regulation of the cerebrovascular response to brain trauma has not been investigated. This study was designed to (1) characterize the cerebrovascular activity of uPA and tPA, (2) investigate the role of nitric oxide (NO) in uPA and tPA vascular activity, and (3) characterize the effect of fluid percussion brain injury (FPI) on vascular responses to uPA and tPA. The closed cranial window technique in chloralose anesthetized newborn pigs was used to measure pial artery diameter and collect CSF for radioimmunoassay (RIA) of cGMP concentration. Topical uPA (10(-9), 10(-7) M) elicited pial artery dilation that was blunted by the NO synthase inhibitor, L-NNA (10(-6) M) (8 +/- 1% and 13 +/- 1 vs. 3 +/- 1% and 7 +/- 2%, respectively). Vasodilation in response to uPA was associated with an increase in CSF cGMP concentration (645 +/- 20, 865 +/- 39 and 1088 +/- 33 fmol/mL cGMP for control, uPA 10(-9), 10(-7) M, respectively). Similar data were obtained for tPA. Pial artery dilation to uPA was blunted following FPI (7 +/- 1% and 12 +/- 1% vs. 3 +/- 1% and 6 +/- 1%, respectively), while uPA-associated release of cGMP was blocked (677 +/- 45, 909 +/- 53, and 1110 +/- 55 vs. 283 +/- 10, 316 +/- 18, and 333 +/- 26 fmol/mL for control, uPA 10(-9), 10(-7) M before and after FPI, respectively). Similar data were obtained for tPA. These data show that uPA and tPA produce pial artery dilation in an NO-dependent manner. FPI blunted uPA and tPA induced pial artery dilation as well as the associated release of cGMP. These data suggest therefore that altered NO function contributes to the impairment of uPA and tPA cerebrovasodilation after brain injury.
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Affiliation(s)
- William M Armstead
- Departments of Anesthesia and Pharmacology, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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Evans DH, Rose RE, Roeser JM, Stidham JD. NaCl transport across the opercular epithelium ofFundulus heteroclitusis inhibited by an endothelin to NO, superoxide, and prostanoid signaling axis. Am J Physiol Regul Integr Comp Physiol 2004; 286:R560-8. [PMID: 14630622 DOI: 10.1152/ajpregu.00281.2003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent evidence suggests that paracrine signaling agents, such as endothelin (ET), nitric oxide (NO), superoxide (O2-), and prostanoids can modulate mammalian renal function by affecting both hemodynamic and epithelial ionic transport pathways. Since these signaling pathways have been described in fish blood vessels, we hypothesized that they may control salt transport across the gill epithelium—the primary site of ion excretion in marine teleost fishes. We found that ET, the NO donors sodium nitroprusside and spermine NONOate, and the prostanoid PGE2each can produce a concentration-dependent reduction in the short circuit current ( Isc) across the isolated opercular epithelium of the killifish ( Fundulus heteroclitus), the generally accepted model for the marine teleost gill epithelium. Sarafotoxin S6c was equipotent to ET-1, suggesting that ETBreceptors are involved. Incubation with NG-nitro-l-arginine methyl ester (l-NAME) or indomethacin reduced the effect of subsequent addition of SRXS6c by 17 and 89%, respectively, suggesting the presence of an ET to NO and PGE axis. The effects of l-NAME and indomethacin were not additive, but the superoxide dismutase mimetic 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPOL) reduced the effect of SRXS6c by 34% and preincubation with l-NAME, indomethacin, and TEMPOL reduced the SRXS6c response to zero. This suggests a direct role for O2-in this axis. COX-2 appears to be the major enzyme involved in this axis because the specific COX-2 inhibitor NS-398 was twice as effective as the COX-1 inhibitor SC560 in inhibiting the SRXS6c effect. The Iscwas stimulated by the EP2agonist butaprost and inhibited by the EP1,3agonist sulprostone, suggesting both stimulatory and inhibitory PGE receptors in this tissue. Carbaprostacyclin (PGI2analog), thromboxane A2, PGF2α, and PGD2did not affect the Isc. Our data are the first to suggest the importance of an ET-stimulated and NO-, O2--, and PGE2-mediated signaling axis that can modify active extrusion of NaCl across the killifish opercular epithelium and, by inference, the marine teleost gill epithelium.
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Affiliation(s)
- David H Evans
- Department of Zoology, University of Florida, Gainesville, Florida 32611, USA.
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DeWitt DS, Prough DS. Traumatic Cerebral Vascular Injury: The Effects of Concussive Brain Injury on the Cerebral Vasculature. J Neurotrauma 2003; 20:795-825. [PMID: 14577860 DOI: 10.1089/089771503322385755] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In terms of human suffering, medical expenses, and lost productivity, head injury is one of the major health care problems in the United States, and inadequate cerebral blood flow is an important contributor to mortality and morbidity after traumatic brain injury. Despite the importance of cerebral vascular dysfunction in the pathophysiology of traumatic brain injury, the effects of trauma on the cerebral circulation have been less well studied than the effects of trauma on the brain. Recent research has led to a better understanding of the physiologic, cellular, and molecular components and causes of traumatic cerebral vascular injury. A more thorough understanding of the direct and indirect effects of trauma on the cerebral vasculature will lead to improvements in current treatments of brain trauma as well as to the development of novel and, hopefully, more effective therapeutic strategies.
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Affiliation(s)
- Douglas S DeWitt
- Charles R. Allen Research Laboratories, Department of Anesthesiology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0830, USA.
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Ross J, Armstead WM. Differential role of PTK and ERK MAPK in superoxide impairment of K(ATP) and K(Ca) channel cerebrovasodilation. Am J Physiol Regul Integr Comp Physiol 2003; 285:R149-54. [PMID: 12793995 DOI: 10.1152/ajpregu.00003.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previously, superoxide (O2 -) has been observed to impair pial artery dilation (PAD) to activators of the ATP-sensitive (KATP) and calcium-sensitive (KCa) K+ channels. This study tested the hypothesis that activation of protein tyrosine kinase (PTK) and the ERK isoform of MAPK by O2 - contribute to impairment of KATP and KCa channel PAD. Exposure of the cerebral cortex to a xanthine oxidase O2 --generating system (OX) blunted PAD to cromakalim, a KATP agonist, but preadministration of genistein, a PTK antagonist, or U-0126, an ERK MAPK inhibitor, almost completely prevented such impairment (11 +/- 1 and 22 +/- 1 vs. 3 +/- 1 and 7 +/- 1 vs. 10 +/- 1 and 16 +/- 2% for cromakalim with 10-8 and 10-6 M PAD during control, OX, and OX + genistein conditions). In contrast, neither genistein nor U-0126 robustly protected PAD to NS-1619, a KCa agonist, after OX exposure (11 +/- 1 and 18 +/- 2 vs. 1 +/- 1 and 2 +/- 1 vs. 4 +/- 1 and 6 +/- 1% for 10-8 and 10-6 M NS-1619 during control, OX, and OX + genistein conditions). These data show that PTK and ERK MAPK activation contribute to O2 --induced KATP and KCa channel PAD impairment and suggest a differential greater role for PTK and ERK MAPK in KATP vs. KCa channel PAD impairment.
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Affiliation(s)
- John Ross
- Dept. of Anesthesia, Univ. of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA
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Erdös B, Miller AW, Busija DW. Alterations in KATP and KCa channel function in cerebral arteries of insulin-resistant rats. Am J Physiol Heart Circ Physiol 2002; 283:H2472-7. [PMID: 12388242 DOI: 10.1152/ajpheart.00516.2002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined whether insulin resistance alters the function of ATP-dependent and Ca(2+)-activated K(+) channels (K(ATP) and K(Ca) channels, respectively) in pressurized isolated middle cerebral arteries (MCAs) from fructose-fed insulin-resistant (IR) and control rats. Blockade of K(Ca) channels with tetraethylammonium chloride (TEA, 2.5 mM) or iberiotoxin (IBTX, 0.1 microM) increased the spontaneously developed tone in control MCAs by 10.5 +/- 1.3% (n = 10) and 13.3 +/- 2.3% (n = 6), respectively. In the IR arteries, TEA induced similar constrictions (8.0 +/- 1.1%, n = 10), but IBTX constricted the IR arteries by only 3.1 +/- 0.9% (n = 8; P < 0.01). Bradykinin (BK)-induced endothelium-mediated relaxation was reduced in IR MCAs. Maximum relaxation to BK (10(-6) M) was 42 +/- 4% in control (n = 9) and 19 +/- 2% in IR (n = 10; P < 0.01) arteries. Pretreatment with TEA, IBTX, or the K(ATP) channel blocker glibenclamide (10 microM) inhibited relaxation to BK in control MCAs but did not alter dilation in IR arteries. Relaxation to the K(ATP) channel opener cromakalim was also diminished in IR MCAs. Maximum relaxation to cromakalim (10(-5) M) was 48 +/- 3% in control (n = 6) and 19 +/- 2% in IR arteries (n = 6; P < 0.01). These findings demonstrate that insulin resistance alters the function of K(ATP) and K(Ca) channels in isolated MCAs and affects the control of resting vascular tone and the mediation of dilator stimuli.
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Affiliation(s)
- Benedek Erdös
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1083, USA.
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Armstead WM. Age dependent NMDA contribution to impaired hypotensive cerebral hemodynamics following brain injury. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2002; 139:19-28. [PMID: 12414090 DOI: 10.1016/s0165-3806(02)00511-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Previous studies have observed that fluid percussion brain injury (FPI) impaired NMDA induced pial artery dilation (PAD) in an age dependent manner. Unrelated studies observed a similar age dependent impairment of hypotensive cerebral autoregulation after FPI. This study was designed to test the hypothesis that NMDA receptor activation contributes to impairment of cerebral autoregulation during hypotension after FPI in an age dependent manner. Therefore, the role of NMDA in impaired hypotensive cerebrovascular regulation after FPI was compared in newborn and juvenile pigs equipped with a closed cranial window. Ten minutes of hypotension (10-15 ml blood/kg) decreased mean arterial blood pressure uniformly in both groups (approximately 44%). In the newborn, hypotensive PAD was blunted within 1 h of FPI but partially protected by pretreatment with the NMDA antagonist MK801 (1 mg/kg i.v.) (34+/-1 vs. 8+/-1 vs. 25+/-2% for sham control, FPI, and FPI-MK801, respectively). Cerebral blood flow (CBF) was reduced during normotension by FPI, further reduced by hypotension, but both were partially protected by MK801 in the newborn (56+/-5, 35+/-2, and 16+/-1 vs. 62+/-6, 45+/-3, and 30+/-2 ml/min 100 g for normotension, normotension-FPI, and hypotension-FPI in the absence and presence of MK801, respectively). In contrast, blunted hypotensive PAD was protected significantly less by MK801 in the juvenile (32+/-2 vs. 7+/-2 vs. 16+/-2% for sham control, FPI, and FPI-MK801, respectively). Similarly, MK801 had less protective effect on normotensive and hypotensive CBF values post FPI in the juvenile. These data indicate that NMDA receptor activation contributes to impaired hypotensive cerebral hemodynamics following brain injury in an age dependent manner.
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Affiliation(s)
- William M Armstead
- Department of Anesthesia, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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Armstead WM. Protein tyrosine kinase and mitogen-activated protein kinase activation contribute to K(ATP) and K(ca) channel impairment after brain injury. Brain Res 2002; 943:276-82. [PMID: 12101050 DOI: 10.1016/s0006-8993(02)02703-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Previous studies have observed that pial artery dilation to activators of the ATP sensitive K (K(ATP)) and calcium sensitive K (K(ca)) channel was blunted following fluid percussion brain injury (FPI) in the piglet. In recent studies in the rat, protein tyrosine kinase (PTK) activation was observed to contribute to K(ATP) channel impairment after FPI, but such a role in K(ca) channel impairment was unclear. This study investigated the role of PTK and mitogen activated protein kinase (MAPK) activation in blunted pial dilation to K(ATP) and K(ca) channel agonists following FPI in piglets equipped with a closed cranial window. Cromakalim and NS1619 (10(-8), 10(-6) M) induced pial artery dilation was blunted after FPI, but partially restored by the PTK inhibitors genistein (10(-6) M) and tyrphostin A23 (10(-5) M) (10+/-1 and 19+/-1%, sham control; 2+/-1 and 4+/-1%, FPI; and 7+/-1 and 11+/-1% FPI-genistein pretreated for NS1619 10(-8), 10(-6) M, respectively). Cromakalim- and NS1619-induced pial dilation was also partially restored after FPI by pretreatment with the MAPK inhibitors U0126 (10(-6) M) and PD98059 (10(-5) M) (12+/-1 and 21+/-1%, sham control; 2+/-1 and 4+/-1%, FPI; and 6+/-1 and 10+/-2%, FPI-U0126 pretreated for NS1619 10(-8), 10(-6) M, respectively). These data suggest that PTK and MAPK activation contribute to K(ATP) and K(ca) channel impairment following FPI.
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Affiliation(s)
- William M Armstead
- Departments of Anesthesia and Pharmacology, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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