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Lapi D, Cammalleri M, Dal Monte M, Di Maro M, Santillo M, Belfiore A, Nasti G, Damiano S, Trio R, Chiurazzi M, De Conno B, Serao N, Mondola P, Colantuoni A, Guida B. The Effects of Angiotensin II or Angiotensin 1-7 on Rat Pial Microcirculation during Hypoperfusion and Reperfusion Injury: Role of Redox Stress. Biomolecules 2021; 11:biom11121861. [PMID: 34944506 PMCID: PMC8699607 DOI: 10.3390/biom11121861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/03/2021] [Accepted: 12/08/2021] [Indexed: 11/16/2022] Open
Abstract
Renin-angiotensin systems produce angiotensin II (Ang II) and angiotensin 1-7 (Ang 1-7), which are able to induce opposite effects on circulation. This study in vivo assessed the effects induced by Ang II or Ang 1-7 on rat pial microcirculation during hypoperfusion-reperfusion, clarifying the mechanisms causing the imbalance between Ang II and Ang 1-7. The fluorescence microscopy was used to quantify the microvascular parameters. Hypoperfusion and reperfusion caused vasoconstriction, disruption of blood-brain barrier, reduction of capillary perfusion and an increase in reactive oxygen species production. Rats treated with Ang II showed exacerbated microvascular damage with stronger vasoconstriction compared to hypoperfused rats, a further increase in leakage, higher decrease in capillary perfusion and marker oxidative stress. Candesartan cilexetil (specific Ang II type 1 receptor (AT1R) antagonist) administration prior to Ang II prevented the effects induced by Ang II, blunting the hypoperfusion-reperfusion injury. Ang 1-7 or ACE2 activator administration, preserved the pial microcirculation from hypoperfusion-reperfusion damage. These effects of Ang 1-7 were blunted by a Mas (Mas oncogene-encoded protein) receptor antagonist, while Ang II type 2 receptor antagonists did not affect Ang 1-7-induced changes. In conclusion, Ang II and Ang 1-7 triggered different mechanisms through AT1R or MAS receptors able to affect cerebral microvascular injury.
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Affiliation(s)
- Dominga Lapi
- Department of Biology, University of Pisa, Via San Zeno, 31, 56127 Pisa, Italy; (M.C.); (M.D.M.)
- Correspondence: ; Tel.: +39-050-2211433
| | - Maurizio Cammalleri
- Department of Biology, University of Pisa, Via San Zeno, 31, 56127 Pisa, Italy; (M.C.); (M.D.M.)
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Via San Zeno, 31, 56127 Pisa, Italy; (M.C.); (M.D.M.)
| | - Martina Di Maro
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Mariarosaria Santillo
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Anna Belfiore
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Gilda Nasti
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Simona Damiano
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Rossella Trio
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Martina Chiurazzi
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Barbara De Conno
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Nicola Serao
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Paolo Mondola
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Antonio Colantuoni
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
| | - Bruna Guida
- Department of Clinical Medicine and Surgery, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy; (M.D.M.); (M.S.); (A.B.); (G.N.); (S.D.); (R.T.); (M.C.); (B.D.C.); (N.S.); (P.M.); (A.C.); (B.G.)
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Ho JK, Moriarty F, Manly JJ, Larson EB, Evans DA, Rajan KB, Hudak EM, Hassan L, Liu E, Sato N, Hasebe N, Laurin D, Carmichael PH, Nation DA. Blood-Brain Barrier Crossing Renin-Angiotensin Drugs and Cognition in the Elderly: A Meta-Analysis. Hypertension 2021; 78:629-643. [PMID: 34148364 PMCID: PMC9009861 DOI: 10.1161/hypertensionaha.121.17049] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/28/2021] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Jean K. Ho
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA
| | - Frank Moriarty
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland, and The Irish Longitudinal Study on Ageing, Trinity College Dublin, Dublin, Ireland
| | - Jennifer J. Manly
- Department of Neurology, Gertrude H. Sergievsky Center, Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Eric B. Larson
- Kaiser Permanente Washington Health Research Institute, Seattle, WA, USA
| | - Denis A. Evans
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Kumar B. Rajan
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Elizabeth M. Hudak
- Department of Psychiatry and Behavioral Neurosciences, University of South Florida, Tampa, FL, USA
| | - Lamiaa Hassan
- Institute of Medical Epidemiology, Biometrics and Informatics, Interdisciplinary Center for Health Sciences, Martin-Luther-University Halle-Wittenberg, Halle/Saale, Saxony-Anhalt, Germany
| | - Enwu Liu
- Mary MacKillop Institute for Health Research, Australian Catholic University, Australia
| | - Nobuyuki Sato
- Department of Cardiovascular Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - Naoyuki Hasebe
- Department of Cardiovascular Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - Danielle Laurin
- Centre d’excellence sur le vieillissement de Québec, Centre de recherche du CHU de Québec and VITAM-Centre de recherche en santé durable, Quebec, Canada
| | - Pierre-Hugues Carmichael
- Centre d’excellence sur le vieillissement de Québec, Centre de recherche du CHU de Québec and VITAM-Centre de recherche en santé durable, Quebec, Canada
| | - Daniel A. Nation
- Department of Psychological Science, University of California, Irvine, Irvine, CA, USA
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
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Abdel-Fattah MM, Messiha BAS, Mansour AM. Modulation of brain ACE and ACE2 may be a promising protective strategy against cerebral ischemia/reperfusion injury: an experimental trial in rats. Naunyn Schmiedebergs Arch Pharmacol 2018; 391:1003-1020. [PMID: 29909460 DOI: 10.1007/s00210-018-1523-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/01/2018] [Indexed: 12/11/2022]
Abstract
The brain renin-angiotensin system (RAS) is considered a crucial regulator for physiological homeostasis and disease progression. We evaluated the protective effects of the angiotensin receptor blocker (ARB) telmisartan and the angiotensin-converting enzyme 2 (ACE2) activator xanthenone on experimental cerebral ischemia/reperfusion (I/R) injury. Rats were divided into a sham control, a cerebral I/R control, a standard treatment (nimodipine, 10 mg/kg/day, 15 days, p.o.), three telmisartan treatments (1, 3, and 10 mg/kg/day, 15 days, p.o.), and three xanthenone treatments (0.5, 1, and 2 mg/kg/day, 15 days, s.c.) groups. One hour after the last dose, all rats except the sham control group were exposed to 30-min cerebral ischemia followed by 24-h reperfusion. Brain ACE and ACE2 activities and the apoptotic marker caspase-3 levels were assessed. Glutathione (GSH), malondialdehyde (MDA), and nitric oxide end products (NOx) as oxidative markers and tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-10 as immunological markers were assessed. Histopathological examination and immunohistochemical evaluation of glial fibrillary acidic protein (GFAP) were performed in cerebral cortex and hippocampus sections. Telmisartan and xanthenone in the higher doses restored MDA, NOx, TNF-α, IL-6, caspase-3, ACE, and GFAP back to normal levels and significantly increased GSH, IL-10, and ACE2 compared to I/R control values. Histopathologically, both agents showed mild degenerative changes and necrosis of neurons in cerebral cortex and hippocampus compared with I/R control group. Modulation of brain RAS, either through suppression of the classic ACE pathway or stimulation of its antagonist pathway ACE2, may be a promising strategy against cerebral I/R damage.
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Affiliation(s)
| | | | - Ahmed Mohamed Mansour
- Pharmacology and Toxicology Department, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
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Tsouli SG, Liberopoulos EN, Kiortsis DN, Mikhailidis DP, Elisaf MS. Combined Treatment With Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers: A Review of the Current Evidence. J Cardiovasc Pharmacol Ther 2016; 11:1-15. [PMID: 16703216 DOI: 10.1177/107424840601100101] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Several studies have shown that angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are useful in the treatment of hypertension, cardiovascular disease, chronic heart failure, and some types of nephropathy. In this context, dual renin-angiotensin system blockade with both angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers may be more effective than treatment with each agent alone. Many clinical trials have demonstrated the beneficial effect of this combined treatment on proteinuria, hypertension, heart failure, and cardiovascular events. Moreover, these studies demonstrated that dual renin-angiotensin system blockade is generally safe and well tolerated. Long-term studies are under way to confirm these effects and also investigate the effectiveness of dual reninangiotensin system blockade on cerebrovascular disease and prevention of type 2 diabetes mellitus. These studies are expected to define the optimal use of combination treatment in everyday clinical practice. This review considers the most important clinical trials that evaluated the effect of dual renin-angiotensin system blockade on blood pressure, heart failure, and renal function.
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Affiliation(s)
- Sofia G Tsouli
- Department of Internal Medicine, School of Medicine, University of Ioannina, Ioannina, Greece
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Hadizad T, Kirkpatrick SA, Mason S, Burns K, Beanlands RS, DaSilva JN. Novel O-[11C]methylated derivatives of candesartan as angiotensin II AT1 receptor imaging ligands: Radiosynthesis and ex vivo evaluation in rats. Bioorg Med Chem 2009; 17:7971-7. [DOI: 10.1016/j.bmc.2009.10.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 10/07/2009] [Accepted: 10/08/2009] [Indexed: 10/20/2022]
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Bourassa EA, Sved AF, Speth RC. Angiotensin modulation of rostral ventrolateral medulla (RVLM) in cardiovascular regulation. Mol Cell Endocrinol 2009; 302:167-75. [PMID: 19027823 PMCID: PMC9686041 DOI: 10.1016/j.mce.2008.10.039] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 10/05/2008] [Accepted: 10/24/2008] [Indexed: 02/07/2023]
Abstract
The rostral ventrolateral medulla (RVLM) and the presympathetic bulbospinal neurons in this region play a critical role in cardiovascular regulation. However, there is ambiguity regarding the precise anatomical coordinates of the RVLM and much still needs to be learned regarding the regulation and neurochemistry of this region. This brief review discusses some of these issues and focuses on the role of angiotensin-mediated signaling in the RVLM in blood pressure regulation.
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Affiliation(s)
- Erick A. Bourassa
- Department of Pharmacology, School of Pharmacy, University of Mississippi, University, MS 38677
- Current address: Biological Sciences, Northwest Missouri State University, Maryville, MO 64468
| | - Alan F. Sved
- Department of Neuroscience and Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Robert C. Speth
- Department of Pharmacology, School of Pharmacy, University of Mississippi, University, MS 38677
- Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS 38677
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Stenman E, Jamali R, Henriksson M, Maddahi A, Edvinsson L. Cooperative effect of angiotensin AT1 and endothelin ETA receptor antagonism limits the brain damage after ischemic stroke in rat. Eur J Pharmacol 2007; 570:142-8. [PMID: 17597600 DOI: 10.1016/j.ejphar.2007.05.049] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 05/14/2007] [Accepted: 05/15/2007] [Indexed: 11/15/2022]
Abstract
Cerebral ischemia results in enhanced expression of smooth muscle cell endothelin and angiotensin receptors in cerebral arteries. We hypothesise that this phenomenon may be detrimental and that acute treatment with a combined non-hypotensive dose of the angiotensin AT(1) receptor inhibitor candesartan and the endothelin ET(A) receptor antagonist ZD1611 reduces the infarct in experimental ischemic stroke. Transient middle cerebral artery occlusion was induced in male Wistar rats by the intraluminal filament technique for 2 h followed by recirculation. The animals received systemic candesartan (0.05 mg/kg/day), ZD1611 (0.15 mg/kg/day), both combined or vehicle with start immediately after the occlusion. After 48 h the rats were sacrificed, the brains sliced and stained with 1% 2, 3, 5-triphenyltetrazolium chloride (TTC) and the volume of ischemic damage determined. The middle cerebral arteries were harvested for immunocytochemical studies of angiotensin AT(1) and endothelin ET(A) receptor expression. Candesartan or ZD1611 did alone not significantly decrease the brain damage or improve neurological scores as compared to vehicle controls. The combined inhibition of angiotensin AT(1) and endothelin ET(A) receptors however decreased the brain damage and improved the neurological scores (both P<0.05). The treatment did not change resting mean arterial blood pressure. In addition, there was an upregulation of angiotensin AT(1) receptors in the ischemic middle cerebral artery smooth muscle cells, which was normalised by the combined treatment. In conclusion, the present study shows that combined inhibition of angiotensin AT(1) and endothelin ET(A) receptors reduces the brain damage and improves the neurological outcome after ischemic stroke in rat.
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Affiliation(s)
- Emelie Stenman
- Institution of Clinical Sciences Lund, Department of Experimental Vascular Research, Lund University, BMC A13, 22184 Lund, Sweden
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Grammatopoulos TN, Jones SM, Ahmadi FA, Hoover BR, Snell LD, Skoch J, Jhaveri VV, Poczobutt AM, Weyhenmeyer JA, Zawada WM. Angiotensin type 1 receptor antagonist losartan, reduces MPTP-induced degeneration of dopaminergic neurons in substantia nigra. Mol Neurodegener 2007; 2:1. [PMID: 17224059 PMCID: PMC1783655 DOI: 10.1186/1750-1326-2-1] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 01/15/2007] [Indexed: 12/21/2022] Open
Abstract
Background Recent attention has focused on understanding the role of the brain-renin-angiotensin-system (RAS) in stroke and neurodegenerative diseases. Direct evidence of a role for the brain-RAS in Parkinson's disease (PD) comes from studies demonstrating the neuroprotective effect of RAS inhibitors in several neurotoxin based PD models. In this study, we show that an antagonist of the angiotensin II (Ang II) type 1 (AT1) receptor, losartan, protects dopaminergic (DA) neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity both in primary ventral mesencephalic (VM) cultures as well as in the substantia nigra pars compacta (SNpc) of C57BL/6 mice (Fig. 1). Results In the presence of exogenous Ang II, losartan reduced MPP+ (5 μM) induced DA neuronal loss by 72% in vitro. Mice challenged with MPTP showed a 62% reduction in the number of DA neurons in the SNpc and a 71% decrease in tyrosine hydroxylase (TH) immunostaining of the striatum, whereas daily treatment with losartan lessened MPTP-induced loss of DA neurons to 25% and reduced the decrease in striatal TH+ immunostaining to 34% of control. Conclusion Our study demonstrates that the brain-RAS plays an important neuroprotective role in the MPTP model of PD and points to AT1 receptor as a potential novel target for neuroprotection.
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Affiliation(s)
- Tom N Grammatopoulos
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, Denver and Health Sciences Center, Denver, Colorado 80262, USA
- Department of Pharmacology, University of Colorado at Denver and Health Sciences Center, Denver, Colorado 80262, USA
| | - Susan M Jones
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, Denver and Health Sciences Center, Denver, Colorado 80262, USA
| | - Ferogh A Ahmadi
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, Denver and Health Sciences Center, Denver, Colorado 80262, USA
- Neuroscience Program, Department of Medicine, Denver and Health Sciences Center, Denver, Colorado 80262, USA
| | - Brian R Hoover
- Department of Pharmacology, University of Colorado at Denver and Health Sciences Center, Denver, Colorado 80262, USA
| | - Lawrence D Snell
- Department of Pharmacology, University of Colorado at Denver and Health Sciences Center, Denver, Colorado 80262, USA
| | - Jesse Skoch
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, Denver and Health Sciences Center, Denver, Colorado 80262, USA
| | - Vimal V Jhaveri
- Department of Pharmacology, University of Colorado at Denver and Health Sciences Center, Denver, Colorado 80262, USA
| | - Andy M Poczobutt
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, Denver and Health Sciences Center, Denver, Colorado 80262, USA
| | - James A Weyhenmeyer
- Department of Cell and Structural Biology, University of Illinois, Urbana, Illinois 61801, USA
| | - W Michael Zawada
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, Denver and Health Sciences Center, Denver, Colorado 80262, USA
- Neuroscience Program, Department of Medicine, Denver and Health Sciences Center, Denver, Colorado 80262, USA
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Grammatopoulos TN, Ahmadi F, Jones SM, Fariss MW, Weyhenmeyer JA, Zawada WM. Angiotensin II protects cultured midbrain dopaminergic neurons against rotenone-induced cell death. Brain Res 2005; 1045:64-71. [PMID: 15910763 DOI: 10.1016/j.brainres.2005.03.038] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 03/03/2005] [Accepted: 03/15/2005] [Indexed: 12/21/2022]
Abstract
In this study, we demonstrate that angiotensin II (Ang II) protects dopamine (DA) neurons from rotenone toxicity in vitro. Primary ventral mesencephalic (VM) cultures from E15 rats were grown for 5 days and then cultured in the presence of the mitochondrial complex I inhibitor, rotenone. Acute exposure (20 h) to 20 nM rotenone reduced the number of tyrosine hydroxylase-positive (TH+) neurons by 50 +/- 6% when compared to untreated cultures. Pre-treatment of VM cultures with 100 nM Ang II decreased TH+ neuronal loss to 25 +/- 10% at the 20-nM rotenone concentration. Ang II in the presence of the angiotensin type 1 receptor (AT1R) antagonist, losartan, was even more effective in protecting DA neurons showing a loss of only 13 +/- 4% at 20 nM rotenone. Conversely, the AT2R antagonist, PD123319, abolished the protective effects of Ang II. Furthermore, both the NMDA receptor antagonist, MK801, and the antioxidant, alpha-tocopheryl succinate (vitamin E analogue), prevented rotenone-induced toxicity. Here, we show that acute exposure of VM cultures to the pesticide rotenone leads to dopaminergic neuronal cell death and that angiotensin acting through the AT2 receptor protects dopamine neurons from rotenone toxicity.
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Affiliation(s)
- Tom N Grammatopoulos
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, School of Pharmacy, University of Colorado Health Sciences Center, Denver, CO 80262, USA
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Kario K, Ishikawa J, Hoshide S, Matsui Y, Morinari M, Eguchi K, Ishikawa S, Shimada K. Diabetic brain damage in hypertension: role of renin-angiotensin system. Hypertension 2005; 45:887-93. [PMID: 15824198 DOI: 10.1161/01.hyp.0000163460.07639.3f] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Diabetes and hypertension are potent risk factors for cerebrovascular disease. We studied the effects of an angiotensin II type 1 receptor blockade (ARB) on brain damage in hypertensives in relation to diabetes. We studied cerebral metabolism (by proton magnetic resonance spectroscopy) and hemodynamics (by phase-contrast magnetic resonance angiography) before and 3 to 4 months after candesartan therapy in 20 diabetic hypertensives (DHTs) and 20 matched nondiabetic hypertensives (HTs). Silent multiple cerebral infarcts detected by brain MRI were more common in DHTs than in HTs (50% versus 25%). Cerebral N-acetyl aspartate (NAA; an indicator of functional neuronal mass) was lower in DHTs than in HTs (8.35 versus 9.58 mmol/kg; P=0.007). Baseline quantitative volume flow in the internal carotid arteries (ICAs) and the middle cerebral arteries (MCAs) was comparable between the 2 groups, whereas cerebrovascular reserve (CVR) assessed using acetazolamide (a cerebral arteriolar dilator) in ICAs (25% versus 35%; P=0.03) and MCAs (20% versus 31%; P=0.01) was lower in DHTs than in HTs. These baseline CVR and NAA values of DHT group were lower than those of 12 matched normotensives (CVR: 44% for ICA; 41% for MCA; NAA: 10.5 mmol/kg; all P<0.005). After candesartan therapy, CVR in ICAs and MCAs was significantly increased (P=0.001) independently of the reduction of the 24-hour blood pressure level, whereas the cerebral NAA level did not change. In conclusion, brain damage is advanced in DHTs. ARB partly improved the impaired cerebral microvascular function in DHTs.
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Affiliation(s)
- Kazuomi Kario
- Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical School, Tochigi, Japan.
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Engelhorn T, Goerike S, Doerfler A, Okorn C, Forsting M, Heusch G, Schulz R. The angiotensin II type 1-receptor blocker candesartan increases cerebral blood flow, reduces infarct size, and improves neurologic outcome after transient cerebral ischemia in rats. J Cereb Blood Flow Metab 2004; 24:467-74. [PMID: 15087716 DOI: 10.1097/00004647-200404000-00012] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The goal of the present study was to test the impact of administration time of the angiotensin II type 1-receptor blocker candesartan on cerebral blood flow (CBF), infarct size, and neuroscore in transient cerebral ischemia. Therefore, 1-hour middle cerebral artery occlusion (MCAO) was followed by reperfusion. Rats received 0.5-mg/kg candesartan intravenously 2 hours before MCAO (pretreatment), 24 hours after MCAO, every 24 hours after MCAO, or 2 hours before and every 24 hours after MCAO. Infarct size (mm3) and a neuroscore at day 7 were compared with controls. CBF was quantified by radiolabeled microspheres and laser-Doppler flowmetry. Compared with controls (95 +/- 8), infarct size in candesartan-treated groups was smaller (59 +/- 5, 68 +/- 10, 28 +/- 3, and 15 +/- 3, respectively; P<0.05). Although there was no difference in neuroscore between pretreatment and controls (1.55 +/- 0.18, 1.80 +/- 0.13), other treatment regimens resulted in improved neuroscores (1.33 +/- 0.16, 1.11 +/- 0.11, 0.73 +/- 0.15; P<0.05). CBF in pretreated animals at 0.5 hours after MCAO was significantly higher than in controls (0.58 +/- 0.09 mL x g(-1) x min(-1) and 44% +/- 7% of baseline compared with 0.49 +/- 0.06 mL x g(-1) x min(-1) and 37% +/- 6%, microspheres and laser-Doppler flowmetry; P<0.05). Thus, candesartan reduces infarct size even if administered only during reperfusion. Apart from pretreatment, other treatment regimens result in significantly improved neuroscores. In the acute phase of cerebral ischemia, candesartan increases CBF.
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Greenland KJ, Mukhopadhyay AK. Selective activation of protein kinase C isoforms by angiotensin II in neuroblastoma X glioma cells. Mol Cell Endocrinol 2004; 213:181-91. [PMID: 15062566 DOI: 10.1016/j.mce.2003.10.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2003] [Accepted: 10/02/2003] [Indexed: 11/19/2022]
Abstract
Differential activation of PKC isoforms by angiotensin II (AII) has been found in a variety of tissues in which this important octapeptide mediates its multitude of effects. To date, the PKC isoforms involved in mediating brain-specific effects are yet to be defined. In the present study, the identity of PKC isoforms coupled to AII stimulation was examined in the neuroblastoma X glioma hybrid cell line, NG108-15, by Western blot analysis. This cell line expresses both the AT1 and AT2 receptor subtypes, with the AT1 subtype predominating, and expression levels highly-upregulated when cells are in the differentiated state. Six PKC isoforms were examined in the present study, including three Ca(2+) dependent (alpha, beta, and gamma), and three Ca(2+) independent (delta, and zeta) isoforms. NG108-15 cells were found to express PKC alpha, delta, and zeta isoforms but not beta or gamma isoforms. Differential sensitivity of the PKC isoforms to AII stimulation was demonstrated, with AII causing a rapid and transient activation of the PKC alpha only in undifferentiated cells, whereas both PKC alpha and isoforms were responsive in differentiated cells. PKC activation was found to be both dose- and time-dependent. The data demonstrate the differential activation of PKC isoforms to AII stimulation in NG108-15 cells, with evidence supporting the involvement of the PKC alpha and isoforms in AII-mediated effects in the brain.
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Affiliation(s)
- Karen J Greenland
- Institute for Hormone and Fertility Research, University of Hamburg, Grandweg 64, Hamburg 22529, Germany.
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Yusuf S. From the HOPE to the ONTARGET and the TRANSCEND studies: challenges in improving prognosis. Am J Cardiol 2002; 89:18A-25A; discussion 25A-26A. [PMID: 11835907 DOI: 10.1016/s0002-9149(01)02323-2] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Heart Outcomes Prevention Evaluation (HOPE) study conclusively demonstrated that ramipril, an angiotensin-converting enzyme (ACE) inhibitor, reduces the risk of cardiovascular death, myocardial infarction (MI), and death in patients at risk for cardiovascular events but without heart failure. The Study to Evaluate Carotid Ultrasound Changes in Patients Treated with Ramipril and Vitamin E (SECURE) substudy demonstrated that ramipril also reduced atherosclerosis. These results suggest that the renin-angiotensin system (RAS) has a more important role in the development and progression of atherosclerosis than previously believed, and they indicate the need for further clinical studies to define the range of benefits available from modifying the RAS. Achieving maximum benefit may require treatment with both an ACE inhibitor and an angiotensin II type-1 receptor blocker (ARB). The Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) study indicated that combining an ACE inhibitor with an ARB decreased blood pressure and improved the ejection fraction more than treatment with either drug alone in patients with congestive heart failure. The Valsartan in Heart Failure Trial (Val-HeFT) showed that the combination of an ACE inhibitor and an ARB reduced hospitalization for heart failure in patients with congestive heart failure by 27.5%, although no decrease in all-cause mortality was observed. The Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET) is a large, long-term study (23,400 patients, 5.5 years). It will compare the benefits of ACE inhibitor treatment, ARB treatment, and treatment with an ACE inhibitor and ARB together, in a study population with established coronary artery disease, stroke, peripheral vascular disease, or diabetes with end-organ damage. Patients with congestive heart failure will be excluded. In a parallel study, patients unable to tolerate an ACE inhibitor will be randomized to receive telmisartan or placebo (the Telmisartan Randomized Assessment Study in ACE-I Intolerant Patients with Cardiovascular Disease [TRANSCEND]). The primary endpoint for both trials is a composite of cardiovascular death, MI, stroke, and hospitalization for heart failure. Secondary endpoints will investigate reductions in the development of diabetes mellitus, nephropathy, dementia, and atrial fibrillation. These 2 trials are expected to provide new insights into the optimal treatment of patients at high risk of complications from atherosclerosis.
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Affiliation(s)
- Salim Yusuf
- Division of Cardiology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
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