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Sukumaran V, Tsuchimochi H, Sonobe T, Shirai M, Pearson JT. Liraglutide Improves Renal Endothelial Function in Obese Zucker Rats on a High-Salt Diet. J Pharmacol Exp Ther 2019; 369:375-388. [DOI: 10.1124/jpet.118.254821] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 03/21/2019] [Indexed: 01/11/2023] Open
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Aquaporin Membrane Channels in Oxidative Stress, Cell Signaling, and Aging: Recent Advances and Research Trends. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:1501847. [PMID: 29770164 PMCID: PMC5892239 DOI: 10.1155/2018/1501847] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/29/2018] [Accepted: 02/20/2018] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species (ROS) are produced as a result of aerobic metabolism and as by-products through numerous physiological and biochemical processes. While ROS-dependent modifications are fundamental in transducing intracellular signals controlling pleiotropic functions, imbalanced ROS can cause oxidative damage, eventually leading to many chronic diseases. Moreover, increased ROS and reduced nitric oxide (NO) bioavailability are main key factors in dysfunctions underlying aging, frailty, hypertension, and atherosclerosis. Extensive investigation aims to elucidate the beneficial effects of ROS and NO, providing novel insights into the current medical treatment of oxidative stress-related diseases of high epidemiological impact. This review focuses on emerging topics encompassing the functional involvement of aquaporin channel proteins (AQPs) and membrane transport systems, also allowing permeation of NO and hydrogen peroxide, a major ROS, in oxidative stress physiology and pathophysiology. The most recent advances regarding the modulation exerted by food phytocompounds with antioxidant action on AQPs are also reviewed.
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García-Arroyo FE, Tapia E, Blas-Marron MG, Gonzaga G, Silverio O, Cristóbal M, Osorio H, Arellano-Buendía AS, Zazueta C, Aparicio-Trejo OE, Reyes-García JG, Pedraza-Chaverri J, Soto V, Roncal-Jiménez C, Johnson RJ, Sánchez-Lozada LG. Vasopressin Mediates the Renal Damage Induced by Limited Fructose Rehydration in Recurrently Dehydrated Rats. Int J Biol Sci 2017; 13:961-975. [PMID: 28924378 PMCID: PMC5599902 DOI: 10.7150/ijbs.20074] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 05/26/2017] [Indexed: 12/26/2022] Open
Abstract
Recurrent dehydration and heat stress cause chronic kidney damage in experimental animals. The injury is exacerbated by rehydration with fructose-containing beverages. Fructose may amplify dehydration-induced injury by directly stimulating vasopressin release and also by acting as a substrate for the aldose reductase-fructokinase pathway, as both of these systems are active during dehydration. The role of vasopressin in heat stress associated injury has not to date been explored. Here we show that the amplification of renal damage mediated by fructose in thermal dehydration is mediated by vasopressin. Fructose rehydration markedly enhanced vasopressin (copeptin) levels and activation of the aldose reductase-fructokinase pathway in the kidney. Moreover, the amplification of the renal functional changes (decreased creatinine clearance and tubular injury with systemic inflammation, renal oxidative stress, and mitochondrial dysfunction) were prevented by the blockade of V1a and V2 vasopressin receptors with conivaptan. On the other hand, there are also other operative mechanisms when water is used as rehydration fluid that produce milder renal damage that is not fully corrected by vasopressin blockade. Therefore, we clearly showed evidence of the cross-talk between fructose, even at small doses, and vasopressin that interact to amplify the renal damage induced by dehydration. These data may be relevant for heat stress nephropathy as well as for other renal pathologies due to the current generalized consumption of fructose and deficient hydration habits.
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Affiliation(s)
| | - Edilia Tapia
- Laboratory of Renal Physiopathology. INC Ignacio Chávez. Mexico City. Mexico.,Dept. of Nephrology. INC Ignacio Chávez. Mexico City. Mexico
| | | | - Guillermo Gonzaga
- Laboratory of Renal Physiopathology. INC Ignacio Chávez. Mexico City. Mexico
| | - Octaviano Silverio
- Laboratory of Renal Physiopathology. INC Ignacio Chávez. Mexico City. Mexico
| | - Magdalena Cristóbal
- Laboratory of Renal Physiopathology. INC Ignacio Chávez. Mexico City. Mexico.,Dept. of Nephrology. INC Ignacio Chávez. Mexico City. Mexico
| | - Horacio Osorio
- Laboratory of Renal Physiopathology. INC Ignacio Chávez. Mexico City. Mexico.,Dept. of Nephrology. INC Ignacio Chávez. Mexico City. Mexico
| | - Abraham S Arellano-Buendía
- Laboratory of Renal Physiopathology. INC Ignacio Chávez. Mexico City. Mexico.,Dept. of Nephrology. INC Ignacio Chávez. Mexico City. Mexico
| | - Cecilia Zazueta
- Dept. of Cardiovascular Biomedicine. INC Ignacio Chávez. Mexico City. Mexico
| | | | - Juan G Reyes-García
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, IPN Mexico City. Mexico
| | | | - Virgilia Soto
- Dept. of Pathology. INC Ignacio Chávez. Mexico City. Mexico
| | | | | | - Laura G Sánchez-Lozada
- Laboratory of Renal Physiopathology. INC Ignacio Chávez. Mexico City. Mexico.,Dept. of Nephrology. INC Ignacio Chávez. Mexico City. Mexico
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Roy J, Galano JM, Durand T, Le Guennec JY, Lee JCY. Physiological role of reactive oxygen species as promoters of natural defenses. FASEB J 2017; 31:3729-3745. [PMID: 28592639 DOI: 10.1096/fj.201700170r] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/22/2017] [Indexed: 02/06/2023]
Abstract
It has been 60 yr since the discovery of reactive oxygen species (ROS) in biology and the beginning of the scientific community's attempt to understand the impact of the unpaired electron of ROS molecules in biological pathways, which was eventually noted to be toxic. Several studies have shown that the presence of ROS is essential in triggering or acting as a secondary factor for numerous pathologies, including metabolic and genetic diseases; however, it was demonstrated that chronic treatment with antioxidants failed to show efficacy and positive effects in the prevention of diseases or health complications that result from oxidative stress. On the contrary, such treatment has been shown to sometimes even worsen the disease. Because of the permanent presence of ROS in organisms, elaborate mechanisms to adapt with these reactive molecules and to use them without necessarily blocking or preventing their actions have been studied. There is now a large body of evidence that shows that living organisms have conformed to the presence of ROS and, in retrospect, have adapted to the bioactive molecules that are generated by ROS on proteins, lipids, and DNA. In addition, ROS have undergone a shift from being molecules that invoked oxidative damage in regulating signaling pathways that impinged on normal physiological and redox responses. Working in this direction, this review unlocks a new conception about the involvement of cellular oxidants in the maintenance of redox homeostasis in redox regulation of normal physiological functions, and an explanation for its essential role in numerous pathophysiological states is noted.-Roy, J., Galano, J.-M., Durand, T., Le Guennec, J.-Y., Lee, J. C.-Y. Physiological role of reactive oxygen species as promoters of natural defenses.
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Affiliation(s)
- Jérôme Roy
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal and Montreal Diabetes Research Center, Department of Nutrition, Université de Montréal, Montreal, Québec, Canada; .,Centre National de la Recherche Scientifique Unité Mixte de Recherche 9214, Inserm Unité 1046 Physiologie et Médecine Expérimentale du Cœur et des Muscles, Université de Montpellier, Montpellier, France
| | - Jean-Marie Galano
- Institut des Biomolécules Max Mousseron, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5247, École Nationale Supérieure de Chimie de Montpellier, Université de Montpellier, Montpellier, France
| | - Thierry Durand
- Institut des Biomolécules Max Mousseron, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5247, École Nationale Supérieure de Chimie de Montpellier, Université de Montpellier, Montpellier, France
| | - Jean-Yves Le Guennec
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 9214, Inserm Unité 1046 Physiologie et Médecine Expérimentale du Cœur et des Muscles, Université de Montpellier, Montpellier, France
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Chaguri JL, Godinho AF, Horta DF, Gonçalves-Rizzi VH, Possomato-Vieira JS, Nascimento RA, Dias-Junior CA. Exposure to fipronil elevates systolic blood pressure and disturbs related biomarkers in plasma of rats. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 42:63-68. [PMID: 26773360 DOI: 10.1016/j.etap.2015.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 12/22/2015] [Accepted: 12/26/2015] [Indexed: 06/05/2023]
Abstract
Recent reports show that fipronil affects non-target organisms, including environmental species populations and potentially humans. We aimed to examine if fipronil exposure affects the systolic blood pressure and related biomarkers. Thus, fipronil was orally administered to rats (30 mg/kg/day) during 15 days (Fipronil group) or physiological solution (Control group). While fipronil increased significantly the systolic blood pressure (158±13 mmHg), no significant changes were observed in Control group (127±3 mmHg). Significantly, higher levels of fipronil in plasma were observed in Fipronil group (0.46±0.09 μg/mL versus 0.17±0.11 μg/mL in Control group). Fipronil group showed lower weight gain compared with Control group. While fipronil resulted in higher concentrations of endothelin-1, reduced antioxidant capacity and lower levels of circulating matrix metalloproteinase 2 (MMP-2) and nitric oxide (NO) metabolites compared to Control group, no alteration was observed in serum biomarkers of renal and hepatic/biliary functional abilities. Therefore, this study suggests that fipronil causes hypertension and endothelin-1 plays a key role. Also, these findings suggest that reductions of both MMP-2 and NO may contribute with the elevation of systolic blood pressure observed with fipronil.
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Affiliation(s)
- Joao Leandro Chaguri
- Center for Toxicological Assistance, Biosciences Institute of Botucatu, Sao Paulo State University - UNESP, Botucatu, Sao Paulo, Brazil
| | - Antonio Francisco Godinho
- Center for Toxicological Assistance, Biosciences Institute of Botucatu, Sao Paulo State University - UNESP, Botucatu, Sao Paulo, Brazil
| | - Daniel França Horta
- Center for Toxicological Assistance, Biosciences Institute of Botucatu, Sao Paulo State University - UNESP, Botucatu, Sao Paulo, Brazil
| | - Victor Hugo Gonçalves-Rizzi
- Department of Pharmacology, Biosciences Institute of Botucatu, Sao Paulo State University - UNESP, Botucatu, Sao Paulo, Brazil
| | - Jose Sergio Possomato-Vieira
- Department of Pharmacology, Biosciences Institute of Botucatu, Sao Paulo State University - UNESP, Botucatu, Sao Paulo, Brazil
| | - Regina Aparecida Nascimento
- Department of Pharmacology, Biosciences Institute of Botucatu, Sao Paulo State University - UNESP, Botucatu, Sao Paulo, Brazil
| | - Carlos Alan Dias-Junior
- Center for Toxicological Assistance, Biosciences Institute of Botucatu, Sao Paulo State University - UNESP, Botucatu, Sao Paulo, Brazil; Department of Pharmacology, Biosciences Institute of Botucatu, Sao Paulo State University - UNESP, Botucatu, Sao Paulo, Brazil.
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Zhou X, Chen K, Lei H, Sun Z. Klotho gene deficiency causes salt-sensitive hypertension via monocyte chemotactic protein-1/CC chemokine receptor 2-mediated inflammation. J Am Soc Nephrol 2014; 26:121-32. [PMID: 24904083 DOI: 10.1681/asn.2013101033] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Klotho (KL) is a newly discovered aging suppressor gene. In mice, the KL gene extends the lifespan when overexpressed and shortens the lifespan when disrupted. This study investigated if KL deficiency affects BP and salt sensitivity using KL mutant heterozygous (+/-) mice and wild-type (WT) mice (9 weeks of age, 16 mice per group). Notably, systolic BP in KL(+/-) mice began to increase at the age of 15 weeks, reached a peak level at the age of 17 weeks, and remained elevated thereafter, whereas systolic BP remained consistent in WT mice. High salt (HS) intake further increased BP in KL(+/-) mice but did not affect BP in WT mice. Blockade of CC chemokine receptor 2 (CCR2), involved in monocyte chemotaxis, by a specific CCR2 antagonist (INCB3284) abolished the HS-induced increase in BP in KL(+/-) mice. Furthermore, HS loading substantially increased the expression of monocyte chemotactic protein-1 and the infiltration of macrophages and T cells in kidneys in KL(+/-) mice, and treatment with INCB3284 abolished these effects. Treatment of KL(+/-) mice with INCB3284 also attenuated the increased renal expressions of serum glucocorticoid-regulated kinase 1, thiazide-sensitive NaCl cotransporter, and ATP synthase β along with the renal structural damage and functional impairment induced by HS loading. In conclusion, KL deficiency caused salt-sensitive hypertension and renal damage by CCR2-mediated inflammation.
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Affiliation(s)
- Xiaoli Zhou
- Department of Cardiology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Kai Chen
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Han Lei
- Department of Cardiology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China; and
| | - Zhongjie Sun
- Department of Cardiology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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Water deprivation induces neurovascular and cognitive dysfunction through vasopressin-induced oxidative stress. J Cereb Blood Flow Metab 2014; 34:852-60. [PMID: 24517977 PMCID: PMC4013763 DOI: 10.1038/jcbfm.2014.24] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 01/03/2014] [Accepted: 01/06/2014] [Indexed: 11/08/2022]
Abstract
Adequate hydration is essential for normal brain function and dehydration induces cognitive deterioration. In addition, dehydration has emerged as a stroke risk factor. However, it is unknown whether alterations in cerebrovascular regulation are responsible for these effects. To address this issue, C57Bl/6 mice were water deprived for 24 or 48 hours and somatosensory cortex blood flow was assessed by laser-Doppler flowmetry in a cranial window. Dehydration increased plasma osmolality and vasopressin levels, and suppressed the increase in blood flow induced by neural activity, by the endothelium-dependent vasodilator acetylcholine and the smooth muscle relaxant adenosine. The cerebrovascular dysfunction was associated with oxidative stress and cognitive deficits, assessed using the Y maze. The vasopressin 1a receptor antagonist SR49059 improved the dehydration-induced oxidative stress and vasomotor dysfunction. Dehydration upregulated endothelin-1 in cerebral blood vessels, an effect blocked by SR49059. Furthermore, the endothelin A receptor antagonist BQ123 ameliorated cerebrovascular function. These findings show for the first time that dehydration alters critical mechanisms regulating the cerebral circulation through vasopressin and oxidative stress. The ensuing cerebrovascular dysregulation may alter cognitive function and increase the brain's susceptibility to cerebral ischemia.
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Moss NG, Kopple TE, Arendshorst WJ. Renal vasoconstriction by vasopressin V1a receptors is modulated by nitric oxide, prostanoids, and superoxide but not the ADP ribosyl cyclase CD38. Am J Physiol Renal Physiol 2014; 306:F1143-54. [PMID: 24623148 DOI: 10.1152/ajprenal.00664.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal blood flow (RBF) responses to arginine vasopressin (AVP) were tested in anesthetized wild-type (WT) and CD38(-/-) mice that lack the major calcium-mobilizing second messenger cyclic ADP ribose. AVP (3-25 ng) injected intravenously produced dose-dependent decreases in RBF, reaching a maximum of 25 ± 2% below basal RBF in WT and 27 ± 2% in CD38(-/-) mice with 25 ng of AVP. Renal vascular resistance (RVR) increased 75 ± 6% and 78 ± 6% in WT and CD38(-/-) mice. Inhibition of nitric oxide (NO) synthase with nitro-L-arginine methyl ester (L-NAME) increased the maximum RVR response to AVP to 308 ± 76% in WT and 388 ± 81% in CD38(-/-) (P < 0.001 for both). Cyclooxygenase inhibition with indomethacin increased the maximum RVR response to 125 ± 15% in WT and 120 ± 14% in CD38(-/-) mice (P < 0.001, <0.05). Superoxide suppression with tempol inhibited the maximum RVR response to AVP by 38% in both strains (P < 0.005) but was ineffective when administered after L-NAME. The rate of RBF recovery (relaxation) after AVP was slowed by L-NAME and indomethacin (P < 0.001, <0.005) but was unchanged by tempol. All vascular responses to AVP were abolished by an AVP V1a receptor antagonist. A V2 receptor agonist or antagonist had no effect on AVP-induced renal vasoconstriction. Taken together, the results indicate that renal vasoconstriction by AVP in the mouse is strongly buffered by vasodilatory actions of NO and prostanoids. The vasoconstriction depends on V1a receptor activation without involvement of CD38 or concomitant vasodilatation by V2 receptors. The role of superoxide is to enhance the contractile response to AVP, most likely by reducing the availability of NO rather than directly stimulating intracellular contraction signaling pathways.
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Affiliation(s)
- Nicholas G Moss
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Tayler E Kopple
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Ishikawa M, Kobayashi N, Sugiyama F, Onoda S, Ishimitsu T. Renoprotective Effect of Vasopressin V2 Receptor Antagonist Tolvaptan in Dahl Rats With End-Stage Heart Failure. Int Heart J 2013; 54:98-106. [DOI: 10.1536/ihj.54.98] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Mayuko Ishikawa
- Department of Cardiology and Nephrology, Dokkyo Medical University School of Medicine
| | - Naohiko Kobayashi
- Department of Cardiology and Nephrology, Dokkyo Medical University School of Medicine
| | - Fumihiro Sugiyama
- Department of Cardiology and Nephrology, Dokkyo Medical University School of Medicine
| | - Sho Onoda
- Department of Cardiology and Nephrology, Dokkyo Medical University School of Medicine
| | - Toshihiko Ishimitsu
- Department of Cardiology and Nephrology, Dokkyo Medical University School of Medicine
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Tyagi S, Sharma S, Budhiraja RD. Effect of phosphatidylinositol 3-kinase-γ inhibitor CAY10505 in hypertension, and its associated vascular endothelium dysfunction in rats. Can J Physiol Pharmacol 2012; 90:881-5. [DOI: 10.1139/y2012-089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study has been designed to investigate the role of phosphatidyl-inositol 3-kinase-γ (PI3Kγ) in deoxycorticosterone acetate salt (DOCA) hypertension induced vascular endothelium dysfunction. Wistar rats were uninephrectomised and DOCA (40 mg·(kg body mass)−1, subcutaneous injection) was administered twice weekly for 6 weeks to produce hypertension. Rats with mean arterial blood pressure ≥ 140 mm Hg (1 mm Hg = 133.322 Pa) were selected as hypertensive. Vascular endothelium dysfunction was assessed in terms of attenuation of acetylcholine-induced endothelium-dependent relaxation (isolated aortic ring preparation), decrease in serum nitrate and (or) nitrite level, as well as reduced level of glutathione and disruption of integrity of vascular endothelium (histopathology). Five weeks of DOCA administration were followed by 7 days of daily administration of PI3Kγ inhibitor (5-[[5-(4-fluorophenyl)-2-furanyl]methylene]-2,4-thiazolidinedione (CAY10505), 0.6 mg·kg−1, per os (p.o.)), atorvastatin (30 mg·kg−1, p.o.), and losartan (25 mg·kg−1, p.o.) (positive control of hypertension), which significantly improved acetylcholine-induced endothelium dependent relaxation, serum nitrate and (or) nitrite level, glutathione level, and the vascular endothelial lining in hypertensive rats.Therefore, it may be concluded that CAY10505, a specific inhibitor of PI3Kγ, improves hypertension-associated vascular endothelial dysfunction. Thus, inhibition of PI3Kγ might be a useful approach in the therapeutics of vascular endothelium dysfunction.
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Affiliation(s)
- Sandeep Tyagi
- Department of Pharmacology, I.S.F. College of Pharmacy, G.T. Road, Moga-142 001 (Punjab), India
| | - Saurabh Sharma
- Department of Pharmacology, I.S.F. College of Pharmacy, G.T. Road, Moga-142 001 (Punjab), India
| | - Ramji Dass Budhiraja
- Department of Pharmacology, I.S.F. College of Pharmacy, G.T. Road, Moga-142 001 (Punjab), India
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Central cardiovascular circuits contribute to the neurovascular dysfunction in angiotensin II hypertension. J Neurosci 2012; 32:4878-86. [PMID: 22492044 DOI: 10.1523/jneurosci.6262-11.2012] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hypertension, a powerful risk factor for stroke and dementia, has damaging effects on the brain and its vessels. In particular, hypertension alters vital cerebrovascular control mechanisms linking neural activity to cerebral perfusion. In experimental models of slow-developing hypertension, free radical signaling in the subfornical organ (SFO), one of the forebrain circumventricular organs, is critical for the hormonal release and sympathetic activation driving the elevation in arterial pressure. However, the contribution of this central mechanism to the cerebrovascular alterations induced by hypertension remains uncertain. We tested the hypothesis that free radical production in the SFO is involved in the alterations in cerebrovascular regulation produced by hypertension. In a mouse model of gradual hypertension induced by chronic administration of subpressor doses of angiotensin II (AngII), suppression of free radicals in the SFO by overexpression of CuZn-superoxide dismutase (CuZnSOD) prevented the alteration in neurovascular coupling and endothelium-dependent responses in somatosensory cortex induced by hypertension. The SFO mediates the dysfunction via two signaling pathways. One involves SFO-dependent activation of the paraventricular hypothalamic nucleus, elevations in plasma vasopressin, upregulation of endothelin-1 in cerebral resistance arterioles and activation of endothelin type A receptors. The other pathway depends on activation of cerebrovascular AngII type 1 (AT1) receptors by AngII. Both pathways mediate vasomotor dysfunction by inducing vascular oxidative stress. The findings implicate for the first time the SFO and its efferent hypothalamic pathways in the cerebrovascular alterations induced by AngII, and identify vasopressin and endothelin-1 as potential therapeutic targets to counteract the devastating effects of hypertension on the brain.
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Belting M, Almgren P, Manjer J, Hedblad B, Struck J, Wang TJ, Bergmann A, Melander O. Vasoactive Peptides with Angiogenesis-Regulating Activity Predict Cancer Risk in Males. Cancer Epidemiol Biomarkers Prev 2012; 21:513-22. [DOI: 10.1158/1055-9965.epi-11-0840] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Yemane H, Busauskas M, Burris SK, Knuepfer MM. Neurohumoral mechanisms in deoxycorticosterone acetate (DOCA)-salt hypertension in rats. Exp Physiol 2009; 95:51-5. [PMID: 19700514 DOI: 10.1113/expphysiol.2008.046334] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This brief review describes the role of neural and non-neural mechanisms during different phases of deoxycorticosterone acetate (DOCA)-salt hypertension. There are contradictory data for and against a role of the sympathetic nervous system and neurohumoral agents, including endothelin and vasopressin. Elucidating the factors responsible for DOCA-salt hypertension will be helpful in understanding the causes of hypertension resulting from hypervolaemia, hyperaldosteronism and high salt intake.
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Affiliation(s)
- Henok Yemane
- Department of Pharmacological and Physiological Science, St Louis University School of Medicine, 1402 South Grand Boulevard, St Louis, MO 63104, USA
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14
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Stojičić S, Milutinović-Smiljanić S, Šarenac O, Milosavljević S, Paton J, Murphy D, Japundžić-Žigon N. Blockade of central vasopressin receptors reduces the cardiovascular response to acute stress in freely moving rats. Neuropharmacology 2008; 54:824-36. [DOI: 10.1016/j.neuropharm.2007.12.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 12/13/2007] [Accepted: 12/21/2007] [Indexed: 11/28/2022]
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15
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Shah DI, Singh M. Possible role of exogenous cAMP to improve vascular endothelial dysfunction in hypertensive rats. Fundam Clin Pharmacol 2007; 20:595-604. [PMID: 17109653 DOI: 10.1111/j.1472-8206.2006.00449.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The study has been designed to investigate the effect of 8-Br-cAMP, an activator of protein kinase A, in hypertension-induced vascular endothelial dysfunction. Rats were uninephroctomized and desoxycortisone acetate (DOCA) (40 mg/kg, s.c.) was administered to rats to produce hypertension (mean arterial blood pressure > 140 mmHg). Vascular endothelial dysfunction was assessed using isolated aortic ring preparation, electron microscopy of thoracic aorta and serum concentration of nitrite/nitrate. The expression of mRNA for p22phox and eNOS was assessed by using reverse transcriptase-polymerase chain reaction. Serum thiobarbituric acid reactive substances concentration and aortic superoxide anion concentration were estimated to assess oxidative stress. 8-Br-cAMP (5 mg/kg, i.p.) or atorvastatin (30 mg/kg, p.o.) prevented hypertension-induced attenuation of acetylcholine-induced endothelium-dependent relaxation, impairment of vascular endothelial lining, decrease in expression of mRNA for endothelial nitric oxide synthase (eNOS), serum nitrite/nitrate concentration and increase in expression of mRNA for p22phox, superoxide anion and serum TBARS. The ameliorative effect of 8-Br-cAMP was prevented by N-nitro-L-arginine methyl ester (25 mg/kg, i.p.) and glibenclamide (30 mg/kg, i.p.). It may be concluded that 8-Br-cAMP may stimulate expression and activity of eNOS and suppress expression of p22phox subunit of NADPH oxidase to reduce oxidative stress and subsequently improve vascular endothelial dysfunction.
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Affiliation(s)
- Dhvanit I Shah
- Department of Pharmaceutical Sciences & Drug Research, Faculty of Medicine, Punjabi University, Patiala 147002, Punjab, India.
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16
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Shah DI, Singh M. Effect of demethylasterriquinone b1 in hypertension associated vascular endothelial dysfunction. Int J Cardiol 2007; 120:317-24. [PMID: 17240464 DOI: 10.1016/j.ijcard.2006.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 10/08/2006] [Accepted: 10/13/2006] [Indexed: 12/21/2022]
Abstract
BACKGROUND Activation of Akt stimulates phosphorylation of eNOS, production of nitric oxide and reduces oxidative stress. The study has been designed to investigate the effect of DAQ B1, an activator of Akt, in hypertension associated vascular endothelial dysfunction. METHODS Rats were uninephroctomized and DOCA (40 mg kg(-1), s.c.) was administered to rats to produce hypertension (MABP>140 mm Hg). Vascular endothelial dysfunction was assessed using isolated aortic ring preparation, electron microscopy of thoracic aorta and serum concentration of nitrite/nitrate. The expression of messenger RNA for p22phox and eNOS was assessed by reverse transcription-polymerase chain reaction. Serum TBARS and aortic superoxide anion were estimated to assess oxidative stress. RESULTS DAQ B1 (5 mg kg(-1), p.o.) or atorvastatin (30 mg kg(-1), p.o.) markedly improved acetylcholine induced endothelium dependent relaxation, vascular endothelial lining, expression of mRNA for eNOS and p22phox, serum nitrite/nitrate concentration and serum TBARS in hypertensive rats. However, this ameliorative effect of DAQ B1 has been prevented by L-NAME (25 mg kg(-1), i.p.), an inhibitor of eNOS. CONCLUSION Therefore, it may be concluded that DAQ B1 induced activation of Akt may activate eNOS and consequently reduce oxidative stress to improve hypertension associated vascular endothelial dysfunction.
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Affiliation(s)
- Dhvanit I Shah
- Department of Pharmaceutical Sciences and Drug Research, Faculty of Medicine, Punjabi University, Patiala-147002 Punjab India.
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17
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Henderson KK, Byron KL. Vasopressin-induced vasoconstriction: two concentration-dependent signaling pathways. J Appl Physiol (1985) 2007; 102:1402-9. [PMID: 17204577 PMCID: PMC2580829 DOI: 10.1152/japplphysiol.00825.2006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Current scientific literature generally attributes the vasoconstrictor effects of [Arg(8)]vasopressin (AVP) to the activation of phospholipase C (PLC) and consequent release of Ca(2+) from the sarcoplasmic reticulum. However, half-maximal activation of PLC requires nanomolar concentrations of AVP, whereas vasoconstriction occurs when circulating concentrations of AVP are orders of magnitude lower. Using cultured vascular smooth muscle cells, we previously identified a novel Ca(2+) signaling pathway activated by 10-100 pM AVP. This pathway is distinguished from the PLC pathway by its dependence on protein kinase C (PKC) and L-type voltage-sensitive Ca(2+) channels (VSCC). In the present study, we used isolated, pressurized rat mesenteric arteries to examine the contributions of these different Ca(2+) signaling mechanisms to AVP-induced vasoconstriction. AVP (10(-14)-10(-6) M) induced a concentration-dependent constriction of arteries that was reversible with a V(1a) vasopressin receptor antagonist. Half-maximal vasoconstriction at 30 pM AVP was prevented by blockade of VSCC with verapamil (10 microM) or by PKC inhibition with calphostin-C (250 nM) or Ro-31-8220 (1 microM). In contrast, acute vasoconstriction induced by 10 nM AVP (maximal) was insensitive to blockade of VSCC or PKC inhibition. However, after 30 min, the remaining vasoconstriction induced by 10 nM AVP was partially dependent on PKC activation and almost fully dependent on VSCC. These results suggest that different Ca(2+) signaling mechanisms contribute to AVP-induced vasoconstriction over different ranges of AVP concentration. Vasoconstrictor actions of AVP, at concentrations of AVP found within the systemic circulation, utilize a Ca(2+) signaling pathway that is dependent on PKC activation and can be inhibited by Ca(2+) channel blockers.
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Affiliation(s)
- Kyle K Henderson
- Department of Pharmacology and Experimental Therapeutics, Loyola University Chicago, Maywood, Illinois 60153, USA
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Shah DI, Singh M. Effect of fasudil on macrovascular disorder-induced endothelial dysfunction. Can J Physiol Pharmacol 2006; 84:835-45. [PMID: 17111028 DOI: 10.1139/y06-036] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The present study has been designed to investigate the effect of fasudil (Rho-kinase inhibitor) in hypercholesterolemia- and hypertension-induced endothelial dysfunction. High fat diet (8 weeks) and desoxycortisone acetate (DOCA) (40 mg·kg–1) were administered (s.c.) to rats to produce hypercholesterolemia and hypertension (mean arterial blood pressure > 120 mmHg), respectively. Endothelial dysfunction was assessed using isolated aortic ring, electron microscopy of thoracic aorta, and serum concentration of nitrite/nitrate. The expression of mRNA for p22phox and eNOS was assessed by using RT-PCR. Serum thiobarbituric acid reactive substances concentration and aortic superoxide anion concentration were estimated to assess oxidative stress. Fasudil (30 mg·kg–1, p.o.) and atorvastatin (30 mg·kg–1, p.o.) treatments markedly prevented hypercholesterolemia- and hypertension-evoked attenuation of acetylcholine-induced endothelium-dependent relaxation, impairment of vascular endothelial lining, decrease in expression of mRNA for eNOS and serum nitrite/nitrate concentration, and an increase in expression of mRNA for p22phox, superoxide anion, and serum thiobarbituric acid reactive substances. The ameliorative effect of fasudil was prevented by L-NAME. In conclusion, fasudil-induced inhibition of Rho-kinase may improve hypercholesterolemia- and hypertension-induced endothelial dysfunction.
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Affiliation(s)
- Dhvanit I Shah
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala-147 002 Punjab, India
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Thakali KM, Lau Y, Fink GD, Galligan JJ, Chen AF, Watts SW. Mechanisms of Hypertension Induced by Nitric Oxide (NO) Deficiency: Focus on Venous Function. J Cardiovasc Pharmacol 2006; 47:742-50. [PMID: 16810074 DOI: 10.1097/01.fjc.0000211789.37658.e4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Loss of endothelial cell-derived nitric oxide (NO) in hypertension is a hallmark of arterial dysfunction. Experimental hypertension created by the removal of NO, however, involves mechanisms in addition to decreased arterial vasodilator activity. These include augmented endothelin-1 (ET-1) release, increased sympathetic nervous system activity, and elevated tissue oxidative stress. We hypothesized that increased venous smooth muscle (venomotor) tone plays a role in Nomega-nitro-L-arginine (LNNA) hypertension through these mechanisms. Rats were treated with the NO synthase inhibitor LNNA (0.5 g/L in drinking water) for 2 weeks. Mean arterial pressure of conscious rats was 119 +/- 2 mm Hg in control and 194 +/- 5 mm Hg in LNNA rats (P<0.05). Carotid arteries and vena cava were removed for measurement of isometric contraction. Maximal contraction to norepinephrine was modestly reduced in arteries from LNNA compared with control rats whereas the maximum contraction to ET-1 was significantly reduced (54% control). Maximum contraction of vena cava to norepinephrine (37% control) also was reduced but no change in response to ET-1 was observed. Mean circulatory filling pressure, an in vivo measure of venomotor tone, was not elevated in LNNA hypertension at 1 or 2 weeks after LNNA. The superoxide scavenger tempol (30, 100, and 300 micromol kg(-1), IV) did not change arterial pressure in control rats but caused a dose-dependent decrease in LNNA rats (-18 +/- 8, -26 +/- 15, and -54 +/- 11 mm Hg). Similarly, ganglionic blockade with hexamethonium caused a significantly greater fall in LNNA hypertensive rats (76 +/- 9 mm Hg) compared with control rats (35 +/- 10 mm Hg). Carotid arteries, vena cava, and sympathetic ganglia from LNNA rats had higher basal levels of superoxide compared with those from control rats. These data suggest that while NO deficiency increases oxidative stress and sympathetic activity in both arterial and venous vessels, the impact on veins does not make a major contribution to this form of hypertension.
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Affiliation(s)
- Keshari M Thakali
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA
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Shah DI, Singh M. Effect of bis(maltolato) oxovanadium on experimental vascular endothelial dysfunction. Naunyn Schmiedebergs Arch Pharmacol 2006; 373:221-9. [PMID: 16736159 DOI: 10.1007/s00210-006-0066-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2005] [Accepted: 03/31/2006] [Indexed: 11/25/2022]
Abstract
The study has been designed to investigate the effect of bis(maltolato) oxovanadium (BMOV), a protein tyrosine phosphatase inhibitor, on hypercholesterolemia and hypertension-induced vascular endothelial dysfunction. High fat diet (8 weeks) and deoxycorticosterone acetate (DOCA; 40 mg kg(-1), s.c.) were administered to rats to produce hypercholesterolemia and hypertension (mean arterial blood pressure >120 mmHg) respectively. Vascular endothelial dysfunction was assessed using isolated aortic ring preparation, electron microscopy of thoracic aorta, and serum concentration of nitrite/nitrate. Serum thiobarbituric acid reactive substances (TBARS) were estimated to assess oxidative stress. BMOV (0.2 mg/ml in drinking water) or atorvastatin (30 mg kg(-1), p.o.) markedly improved acetylcholine-evoked endothelium-dependent relaxation, lining of vascular endothelium, serum nitrite/nitrate concentration, and serum TBARS in hypercholesterolemic and hypertensive rats. However, this ameliorative effect of BMOV has been prevented by L-NAME (25 mg kg(-1), i.p.), an inhibitor of NOS, or by glibenclamide (5 mg kg(-1), i.p.), a blocker of ATP-sensitive K(+) channels. It may be concluded that BMOV-induced inhibition of PTPase may improve vascular endothelial dysfunction.
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Affiliation(s)
- Dhvanit I Shah
- Department of Pharmaceutical Sciences and Drug Research, Faculty of Medicine, Punjabi University, Patiala, 147002, Punjab, India
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21
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Cingolani HE, Villa-Abrille MC, Cornelli M, Nolly A, Ennis IL, Garciarena C, Suburo AM, Torbidoni V, Correa MV, Camiliónde Hurtado MC, Aiello EA. The positive inotropic effect of angiotensin II: role of endothelin-1 and reactive oxygen species. Hypertension 2006; 47:727-34. [PMID: 16505203 DOI: 10.1161/01.hyp.0000208302.62399.68] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Many effects believed to be because of angiotensin II (Ang II) are attributable to the action of endothelin (ET)-1, which is released/produced by Ang II. We investigated whether Ang II elicits its positive inotropic effect (PIE) by the action of endogenous ET-1, in addition to the role played by reactive oxygen species (ROS) in this mechanism. Cat cardiomyocytes were used for: (1) sarcomere shortening measurements; (2) ROS measurements by epifluorescence; (3) immunohistochemical staining for preproET-1, BigET-1, and ET-1; and (4) measurement of preproET-1 mRNA by RT-PCR. Cells were exposed to 1 nmol/L Ang II for 15 minutes. This low concentration of Ang II increases sarcomere shortening by 29.2+/-3.7% (P<0.05). This PIE was abrogated by Na+/H+ exchanger or Na+/Ca2+ exchanger reverse mode inhibition. The production of ROS increased in response to Ang II treatment (DeltaROS respect to control: 68+/-15 fluorescence units; P<0.05). The Ang II-induced PIE and ROS production were blocked by the Ang II type 1 receptor blocker losartan, the nonselective ET-1 receptor blocker TAK044, the selective ETA receptor blocker BQ-123, or the ROS scavenger N-(2-mercapto-propionyl)glycine. Exogenous ET-1 (0.4 nmol/L) induced a similar PIE and increase in ROS production to those caused by Ang II. Immunostaining for preproET-1, BigET-1, and ET-1 was positive in cardiomyocytes. The preproET-1 mRNA abundance increased from 100+/-4.6% in control to 241.9+/-39.9% in Ang II-treated cells (P<0.05). We conclude that the PIE after exposure to 1 nmol/L Ang II is due to endogenous ET-1 acting through the ETA receptor and triggering ROS production, Na+/H+ exchanger stimulation, and Na+/Ca2+ exchanger reverse mode activation.
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Affiliation(s)
- Horacio E Cingolani
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina.
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Vidal A, Sun Y, Bhattacharya SK, Ahokas RA, Gerling IC, Weber KT. Calcium paradox of aldosteronism and the role of the parathyroid glands. Am J Physiol Heart Circ Physiol 2006; 290:H286-94. [PMID: 16373592 DOI: 10.1152/ajpheart.00535.2005] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The hypercalciuria and hypermagnesuria that accompany aldosteronism contribute to a fall in plasma ionized extracellular Ca2+ and Mg2+ concentrations ([Ca2+]o and [Mg2+]o). Despite these losses and the decline in extracellular levels of these cations, total intracellular and cytosolic free Ca2+ concentration ([Ca2+]i) is increased and oxidative stress is induced. This involves diverse tissues, including peripheral blood mononuclear cells (PBMC) and plasma. The accompanying elevation in plasma parathyroid hormone (PTH) and reduction in bone mineral density caused by aldosterone (Aldo)-1% NaCl treatment (AldoST) led us to hypothesize that Ca2+ loading and altered redox state are due to secondary hyperparathyroidism (SHPT). Therefore, we studied the effects of total parathyroidectomy (PTx). In rats receiving AldoST, without or with a Ca2+-supplemented diet and/or PTx, we monitored urinary Ca2+ and Mg2+ excretion; plasma [Ca2+]o, [Mg2+]o, and PTH; PBMC [Ca2+]i and H2O2 production; plasma α1-antiproteinase activity; total Ca2+ and Mg2+ in bone, myocardium, and rectus femoris; and gp91phox labeling in the heart. We found that 1) the hypercalciuria and hypermagnesuria and decline ( P < 0.05) in plasma [Ca2+]o and [Mg2+]o that occur with AldoST were not altered by the Ca2+-supplemented diet alone or with PTx; 2) the rise ( P < 0.05) in plasma PTH with AldoST, with or without the Ca2+-supplemented diet, was prevented by PTx; 3) increased ( P < 0.05) PBMC [Ca2+]i and H2O2 production, increased total Ca2+ in heart and skeletal muscle, and fall in bone Ca2+ and Mg2+ and plasma α1-antiproteinase activity with AldoST were abrogated ( P < 0.05) by PTx; and 4) gp91phox activation in right and left ventricles at 4 wk of AldoST was attenuated by PTx. AldoST is accompanied by SHPT, with parathyroid gland-derived calcitropic hormones being responsible for Ca2+ overload in diverse tissues and induction of oxidative stress. SHPT plays a permissive role in the proinflammatory vascular phenotype.
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Affiliation(s)
- Alex Vidal
- Division of Cardiovascular Diseases, Univ. of Tennessee Health Science Center, 920 Madison Ave., Memphis, TN 38163, USA
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23
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Affiliation(s)
- David M Pollock
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912-2500, USA.
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Zheng JS, Yang XQ, Lookingland KJ, Fink GD, Hesslinger C, Kapatos G, Kovesdi I, Chen AF. Gene transfer of human guanosine 5'-triphosphate cyclohydrolase I restores vascular tetrahydrobiopterin level and endothelial function in low renin hypertension. Circulation 2003; 108:1238-45. [PMID: 12925450 DOI: 10.1161/01.cir.0000089082.40285.c3] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND We recently reported that arterial superoxide (O2-) is augmented by increased endothelin-1 (ET-1) in deoxycorticosterone acetate (DOCA)-salt hypertension, a model of low renin hypertension. Tetrahydrobiopterin (BH4), a potent reducing molecule with antioxidant properties and an essential cofactor for endothelial nitric oxide synthase, protects against O2--induced vascular dysfunction. However, the interaction between O2- and BH4 on endothelial function and the underlying mechanisms are unknown. METHODS AND RESULTS The present study tested the hypothesis that BH4 deficiency due to ET-1-induced O2- leads to impaired endothelium-dependent relaxation and that gene transfer of human guanosine 5'-triphosphate (GTP) cyclohydrolase I (GTPCH I), the first and rate-limiting enzyme for BH4 biosynthesis, reverses such deficiency and endothelial dysfunction in carotid arteries of DOCA-salt rats. There were significantly increased arterial O2- levels and decreased GTPCH I activity and BH4 levels in DOCA-salt compared with sham rats. Treatment of arteries of DOCA-salt rats with the selective ETA receptor antagonist ABT-627, NADPH oxidase inhibitor apocynin, or superoxide dismutase (SOD) mimetic tempol abolished O2- and restored BH4 levels. Basal arterial NO release and endothelium-dependent relaxations were impaired in DOCA-salt rats, conditions that were improved by apocynin or tempol treatment. Gene transfer of GTPCH I restored arterial GTPCH I activity and BH4 levels, resulting in reduced O2- and improved endothelium-dependent relaxation and basal NO release in DOCA-salt rats. CONCLUSIONS These results indicate that a BH4 deficiency resulting from ET-1-induced O2- via an ETA/NADPH oxidase pathway leads to endothelial dysfunction, and gene transfer of GTPCH I reverses the BH4 deficiency and endothelial dysfunction by reducing O2- in low renin mineralocorticoid hypertension.
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Affiliation(s)
- Jie-Sheng Zheng
- Department of Pharmacology and Toxicology and the Neuroscience Program, B403 Life Sciences Building, Michigan State University, East Lansing, Mich 48824-1317, USA
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Li L, Watts SW, Banes AK, Galligan JJ, Fink GD, Chen AF. NADPH oxidase-derived superoxide augments endothelin-1-induced venoconstriction in mineralocorticoid hypertension. Hypertension 2003; 42:316-21. [PMID: 12885792 DOI: 10.1161/01.hyp.0000084853.47326.f2] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Deoxycorticosterone acetate (DOCA)-salt hypertension is characterized by low renin/angiotensin but increased arterial superoxide levels. We have recently reported that the arterial endothelin-1 (ET-1) level is increased, resulting in NADPH oxidase activation and superoxide generation. However, the effect of ET-1 on venous superoxide production and its relation to venoconstriction are unknown. The present study tested the hypotheses that ET-1 stimulates venous NADPH oxidase and superoxide via its ET(A) receptors, resulting in enhanced venoconstriction in DOCA-salt hypertensive rats. Treatment with ET-1 (0.01 to 1 nmol/L), but not the selective ET(B) receptor agonist sarafotoxin s6c, of vena cavas of normal rats concentration-dependently increased superoxide levels, an effect that was abolished by the selective ET(A) receptor antagonist ABT-627. Although the ET-1 level was not increased in the vena cava and plasma, both venous NADPH oxidase activity and superoxide levels were significantly higher in DOCA-salt compared with sham rats. Moreover, ET-1 treatment (10(-9) mol/L, 10 minutes) of isolated vena cavas further elevated superoxide levels in DOCA-salt rats only but not sham rats, an effect that was abrogated by the superoxide scavenger tempol. Similarly, ET-1-induced contractions of isolated vena cavas of DOCA-salt but not sham rats were significantly inhibited by tempol. The NADPH oxidase inhibitor apocynin significantly reduced superoxide levels in vena cavas of DOCA-salt rats and in ET-1-treated vena cavas of normal rats. Finally, in vivo ET(A) receptor blockade by ABT-627 significantly lowered venous superoxide levels and blood pressure in DOCA-salt but not sham rats. These results suggest that superoxide contributes to ET-1-induced venoconstriction through an elevated venous NADPH oxidase activity in mineralocorticoid hypertension.
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Affiliation(s)
- Lixin Li
- Department of Pharmacology and Toxicology and the Neuroscience Program, Michigan State University, East Lansing, MI 48824-1317, USA
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