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Dalco LJ, Dave KR. Diabetic Rodent Models for Chronic Stroke Studies. Methods Mol Biol 2023; 2616:429-439. [PMID: 36715951 DOI: 10.1007/978-1-0716-2926-0_30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Chronic diabetes may cause secondary complications like stroke and also increase post-stroke brain damage. In stroke research, the Stroke Therapy Academic Industry Roundtable (STAIR) identified criteria to increase translational value of preclinical studies, which highlighted the importance of using animal models of comorbidities. Numerous animal models have been used to study the aggravation of ischemic brain damage in diabetics. In this chapter, we discuss rat and mouse models of streptozotocin (STZ)-induced diabetes, with an efficient method provided. We also provide an overview of spontaneously diabetic rodent models. We present different pathophysiological features of diabetes in each rodent model along with the advantages and disadvantages of each model. Utilizing these models may aid the advancement of novel treatments and therapies to lower ischemic brain damage in patients of diabetes.
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Affiliation(s)
- Lea Julie Dalco
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, Department of Neurology and Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Kunjan R Dave
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, Department of Neurology and Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA.
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2
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Fouda AY, Ahmed HA, Pillai B, Kozak A, Hardigan T, Ergul A, Fagan SC, Ishrat T. Contralesional angiotensin type 2 receptor activation contributes to recovery in experimental stroke. Neurochem Int 2022; 158:105375. [PMID: 35688299 PMCID: PMC9719365 DOI: 10.1016/j.neuint.2022.105375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 01/16/2023]
Abstract
We and others have previously shown that angiotensin II receptor type 2 receptor (AT2R) is upregulated in the contralesional hemisphere after stroke in normoglycemic Wistar rats. In this study, we examined the expression of AT2R in type 2 diabetic Goto-Kakizaki (GK) rats and control Wistars after stroke. We also tested the contribution of the contralesional AT2R in recovery after stroke through a specific knockdown of the AT2R in this hemisphere only. Two experiments were conducted. In the first experiment, GK rats were subjected to middle cerebral artery occlusion (MCAO) and treated with the angiotensin II receptor type 1 receptor (AT1R) blocker candesartan or saline at reperfusion. Stroke outcomes, as well as AT2R expression, were examined and compared to control Wistars at 24 h. In the second experiment, localized AT2R knockdown was achieved through intrastriatal injection of short hairpin RNA (shRNA) lentiviral particles or non-targeting control into the left-brain hemisphere of Wistar rats. After 14 days, rats were subjected to right MCAO and treated with the AT2R agonist, Compound 21 (C21), or saline for 7 days. Behavioral outcomes were assessed for up to 10 days. In the first experiment, stroke reduced the expression of AT2R in GK rats. Candesartan treatment failed to improve the neurobehavioral outcomes, preserve vascular integrity or reduce oxidative/nitrative stress or apoptotic markers at 24 h post stroke in these animals. In the second experiment, contralesional AT2R knockdown reduced the C21-mediated functional recovery after stroke. In conclusion, contralesional AT2R upregulation after stroke is blunted in diabetic rats which show reduced sensitivity to post-stroke candesartan treatment. Contralesional AT2R could be involved in C21-mediated functional recovery after stroke.
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Affiliation(s)
- Abdelrahman Y. Fouda
- University of Arkansas for Medical Sciences, Little Rock, AR, USA,Department of Clinical Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt,Corresponding author. University of Arkansas for Medical Sciences, Department of Pharmacology and Toxicology, Little Rock, AR, USA. (A.Y. Fouda)
| | - Heba A. Ahmed
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Bindu Pillai
- Charlie Norwood VA Medical Center, Augusta, GA, USA,Center for Pharmacy and Experimental Therapeutics, University of Georgia, College of Pharmacy, Augusta, GA, USA
| | - Anna Kozak
- Charlie Norwood VA Medical Center, Augusta, GA, USA,Center for Pharmacy and Experimental Therapeutics, University of Georgia, College of Pharmacy, Augusta, GA, USA
| | - Trevor Hardigan
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai Hospital, New York, NY, USA
| | - Adviye Ergul
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA,Ralph H. Jackson VA Medical Center, Charleston, SC, USA
| | - Susan C. Fagan
- Charlie Norwood VA Medical Center, Augusta, GA, USA,Center for Pharmacy and Experimental Therapeutics, University of Georgia, College of Pharmacy, Augusta, GA, USA
| | - Tauheed Ishrat
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA,Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA,Corresponding author. University of Tennessee Health Science Center, College of Medicine, Department of Anatomy and Neurobiology, 875 Monroe Avenue, Wittenborg Bldg, Room-231, Memphis, TN, 38163, USA. (T. Ishrat)
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3
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Mannan A, Garg N, Singh TG, Kang HK. Peroxisome Proliferator-Activated Receptor-Gamma (PPAR-ɣ): Molecular Effects and Its Importance as a Novel Therapeutic Target for Cerebral Ischemic Injury. Neurochem Res 2021; 46:2800-2831. [PMID: 34282491 DOI: 10.1007/s11064-021-03402-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/10/2021] [Accepted: 07/12/2021] [Indexed: 02/06/2023]
Abstract
Cerebral ischemic injury is a leading cause of death and long-term disability throughout the world. Peroxisome proliferator-activated receptor gamma (PPAR-ɣ) is a ligand-activated nuclear transcription factor that is a member of the PPAR family. PPAR-ɣ has been shown in several in vitro and in vivo models to prevent post-ischemic inflammation and neuronal damage by negatively controlling the expression of genes modulated by cerebral ischemic injury, indicating a neuroprotective effect during cerebral ischemic injury. A extensive literature review of PubMed, Medline, Bentham, Scopus, and EMBASE (Elsevier) databases was carried out to understand the nature of the extensive work done on the mechanistic role of Peroxisome proliferator activated receptor gamma and its modulation in Cerebral ischemic injury. PPAR-ɣ can interact with specific DNA response elements to control gene transcription and expression when triggered by its ligand. It regulates lipid metabolism, improves insulin sensitivity, modulates antitumor mechanisms, reduces oxidative stress, and inhibits inflammation. This review article provides insights on the current state of research into the neuroprotective effects of PPAR-ɣ in cerebral ischemic injury, as well as the cellular and molecular mechanisms by which these effects are modulated, such as inhibition of inflammation, reduction of oxidative stress, suppression of pro-apoptotic production, modulation of transcription factors, and restoration of injured tissue through neurogenesis and angiogenesis.
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Affiliation(s)
- Ashi Mannan
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Nikhil Garg
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | | | - Harmeet Kaur Kang
- Chitkara School of Health Sciences, Chitkara University, Punjab, India
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Li YY, Guo JH, Liu YQ, Dong JH, Zhu CH. PPARγ Activation-Mediated Egr-1 Inhibition Benefits Against Brain Injury in an Experimental Ischaemic Stroke Model. J Stroke Cerebrovasc Dis 2020; 29:105255. [PMID: 32992165 DOI: 10.1016/j.jstrokecerebrovasdis.2020.105255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Inflammatory response is a critical contributor to cerebral ischaemia injuries and blood-brain barrier (BBB) dysfunction. Early growth response-1 (Egr-1), an oxygen-sensing transcription factor which is rapidly and markedly triggered in ischaemic events, acts as a master switch coordinating the upregulation of multiple target proinflammatory genes. Here, we explored whether peroxisome proliferator-activated receptor-gamma (PPARγ) activation by telmisartan can modulate Egr-1 expression and the subsequent inflammatory responses in a rat model of cerebral ischaemia. METHODS Cerebral ischaemia was induced in rats by middle cerebral artery occlusion (MCAO). Brain injury was evaluated by brain water content, infarct volume, and Evans blue dye extravasation. Egr-1 and claudin-5 levels were assessed by western blot and real-time polymerase chain reaction. RESULTS MCAO-provoked Egr-1 expression was time dependent, peaking at 24 h and continuing to 72 h. The elevation in Egr-1 was coupled with a reduction in claudin-5. Telmisartan treatment significantly corrected the alterations of Egr-1 and claudin-5, alleviated the neurological deficits, and reduced brain water content, infarct volume, and Evans blue dye extravasation 24 h after MCAO. However, all the benefits of telmisartan were reversed by antagonising PPARγ with GW9662. CONCLUSION Egr-1, a proinflammatory factor, is positively associated with post-ischaemic inflammation and the associated BBB dysfunction. PPARγ serves as an upstream transcription factor of the Egr-1 cascade. Targeting Egr-1 may emerge as a potential strategy to suppress inflammatory responses following ischaemic stroke.
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Affiliation(s)
- Yue-Yi Li
- School of Basic Medicine, Hebei Medical University, PR China
| | - Jia-Hui Guo
- Department of Neurology, Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, PR China
| | - Ya-Qiang Liu
- Department of Neurology, Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, PR China
| | - Jing-Hui Dong
- Department of Physiology, Hebei Medical University, PR China
| | - Chun-Hua Zhu
- Department of Neurology, Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, PR China.
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5
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Gamdzyk M, Lenahan C, Tang J, Zhang JH. Role of peroxisome proliferator-activated receptors in stroke prevention and therapy-The best is yet to come? J Neurosci Res 2020; 98:2275-2289. [PMID: 32772463 DOI: 10.1002/jnr.24709] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/08/2020] [Accepted: 07/20/2020] [Indexed: 12/25/2022]
Abstract
Role of peroxisome proliferator-activated receptors (PPARs) in the pathophysiology of stroke and protective effects of PPAR ligands have been widely investigated in the last 20 years. Activation of all three PPAR isoforms, but especially PPAR-γ, was documented to limit postischemic injury in the numerous in vivo, as well as in in vitro studies. PPARs have been demonstrated to act on multiple mechanisms and were shown to activate multiple protective pathways related to inflammation, apoptosis, BBB protection, neurogenesis, and oxidative stress. The aim of this review was to summarize two decades of PPAR research in stroke with emphasis on in vivo animal studies. We focus on each PPAR receptor separately and detail their implication in stroke. This review also discusses recent clinical efforts in the field and the epidemiological data with regard to role of PPAR polymorphisms in susceptibility to stroke, and tries to draw conclusions and describe future perspectives.
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Affiliation(s)
- Marcin Gamdzyk
- Department of Physiology and Pharmacology, Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Cameron Lenahan
- Department of Physiology and Pharmacology, Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Jiping Tang
- Department of Physiology and Pharmacology, Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - John H Zhang
- Department of Physiology and Pharmacology, Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.,Department of Anesthesiology, Neurosurgery and Neurology, Loma Linda University School of Medicine, Loma Linda, CA, USA
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Hegazy N, Rezq S, Fahmy A. Mechanisms Involved in Superiority of Angiotensin Receptor Blockade over ACE Inhibition in Attenuating Neuropathic Pain Induced in Rats. Neurotherapeutics 2020; 17:1031-1047. [PMID: 32804335 PMCID: PMC7609714 DOI: 10.1007/s13311-020-00912-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although previous reports described the beneficial role of angiotensin-converting enzyme inhibitors (ACE-Is) or AT1 receptor blockers (ARBs) in attenuating neuropathic pain (NP), no study has yet explored the exact underlying mechanisms, as well as the superiority of using centrally versus peripherally acting renin-angiotensin-aldosterone system (RAAS) drugs in NP. We investigated the effects of 14 days of treatment with centrally (telmisartan and ramipril) or peripherally (losartan and enalapril) acting ARBs and ACE-Is, respectively, in attenuating peripheral NP induced by sciatic nerve chronic constriction injury (CCI) in rats. We also compared these with the effects of pregabalin, the standard treatment for NP. Behavioral changes, inflammatory markers (NFкB, TNF-α, COX-2, PGE2, and bradykinin), oxidative stress markers (NADPH oxidase and catalase), STAT3 activation, levels of phosphorylated P38-MAPK, ACE, AT1 receptor (AT1R), and AT2 receptor (AT2R), as well as histopathological features, were assessed in the brainstem and sciatic nerve. CCI resulted in clear pain-related behavior along with increased levels of inflammatory and oxidative stress markers, and STAT3 activity, as well as increased levels of phosphorylated P38-MAPK, ACE, AT1R, and AT2R, along with worsened histopathological findings in both the brainstem and sciatic nerve. ARBs improved both animal behavior and all measured parameters in CCI rats and were more effective than ACE-Is. At the tested doses, centrally acting ARBs or ACE-Is were not superior to the peripherally acting drugs of the same category. These findings suggest that ARBs (centrally or peripherally acting) are an effective treatment modality for NP.
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Affiliation(s)
- Nora Hegazy
- Department of Pharmacology and Toxicology, School of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Samar Rezq
- Department of Pharmacology and Toxicology, School of Pharmacy, Zagazig University, Zagazig, 44519, Egypt.
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 North State Street, Jackson, 39216, MS, USA.
| | - Ahmed Fahmy
- Department of Pharmacology and Toxicology, School of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
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The Role of Sartans in the Treatment of Stroke and Subarachnoid Hemorrhage: A Narrative Review of Preclinical and Clinical Studies. Brain Sci 2020; 10:brainsci10030153. [PMID: 32156050 PMCID: PMC7139942 DOI: 10.3390/brainsci10030153] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 12/30/2022] Open
Abstract
Background: Delayed cerebral vasospasm (DCVS) due to aneurysmal subarachnoid hemorrhage (aSAH) and its sequela, delayed cerebral ischemia (DCI), are associated with poor functional outcome. Endothelin-1 (ET-1) is known to play a major role in mediating cerebral vasoconstriction. Angiotensin-II-type-1-receptor antagonists such as Sartans may have a beneficial effect after aSAH by reducing DCVS due to crosstalk with the endothelin system. In this review, we discuss the role of Sartans in the treatment of stroke and their potential impact in aSAH. Methods: We conducted a literature research of the MEDLINE PubMed database in accordance with PRISMA criteria on articles published between 1980 to 2019 reviewing: "Sartans AND ischemic stroke". Of 227 studies, 64 preclinical and 19 clinical trials fulfilled the eligibility criteria. Results: There was a positive effect of Sartans on ischemic stroke in both preclinical and clinical settings (attenuating ischemic brain damage, reducing cerebral inflammation and infarct size, increasing cerebral blood flow). In addition, Sartans reduced DCVS after aSAH in animal models by diminishing the effect of ET-1 mediated vasoconstriction (including cerebral inflammation and cerebral epileptogenic activity reduction, cerebral blood flow autoregulation restoration as well as pressure-dependent cerebral vasoconstriction). Conclusion: Thus, Sartans might play a key role in the treatment of patients with aSAH.
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Opportunities and Limitations of Vascular Risk Factor Models in Studying Plasticity-Promoting and Restorative Ischemic Stroke Therapies. Neural Plast 2019; 2019:9785476. [PMID: 31827502 PMCID: PMC6885287 DOI: 10.1155/2019/9785476] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/02/2019] [Accepted: 10/24/2019] [Indexed: 12/24/2022] Open
Abstract
Major efforts are currently made promoting neuronal plasticity and brain remodeling in the postacute stroke phase. Experimental studies evaluating new stroke therapies are mostly performed in rodents, which compared to humans exhibit a short lifespan. These studies widely employ young, otherwise healthy, rodents that lack the vascular risk factors and comorbidities of stroke patients. These risk factors compromise postischemic neurological recovery and brain plasticity and in several contexts reduce the brain responsiveness to recovery-inducing plasticity-promoting treatments. By examining risk factor models, which have hitherto been used for studying experimentally induced ischemic stroke, this review outlines the possibilities and limitations of risk factor models in the evaluation of plasticity-promoting and restorative stroke treatments.
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Lenart L, Balogh DB, Lenart N, Barczi A, Hosszu A, Farkas T, Hodrea J, Szabo AJ, Szigeti K, Denes A, Fekete A. Novel therapeutic potential of angiotensin receptor 1 blockade in a rat model of diabetes-associated depression parallels altered BDNF signalling. Diabetologia 2019; 62:1501-1513. [PMID: 31053872 PMCID: PMC6647092 DOI: 10.1007/s00125-019-4888-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/02/2019] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS Diabetes is a worldwide epidemic linked with diverse diseases of the nervous system, including depression. A few studies suggested a connection between renin-angiotensin-aldosterone system blockers and reduced depressive symptoms, although underlying mechanisms are unclear. Here we investigated the antidepressant effect and the mechanisms of action of the angiotensin receptor 1 blocker (ARB) losartan in an experiential model of diabetes-associated depression. METHODS Experimental diabetes was induced by streptozotocin in adult male Wistar rats. After 5 weeks of diabetes, rats were treated for 2 weeks with a non-pressor oral dose of losartan (20 mg/kg). In protocol 1, cerebrovascular perfusion and glial activation were evaluated by single-photon emission computed tomography-MRI and immunohistochemistry. In protocol 2, behaviour studies were performed (forced swim test and open field test). Hippocampal proinflammatory response and brain-derived neurotrophic factor (BDNF) signalling were also assessed. RESULTS Here, we show that diabetic rats exhibit depression-like behaviour, which can be therapeutically reversed by losartan. This action of losartan occurs via changes in diabetes-induced neuroinflammatory responses rather than altered cerebral perfusion. We also show that as a part of its protective effect losartan restores BDNF production in astrocytes and facilitates BDNF-tropomyosin receptor kinase B-cAMP response element-binding protein signalling in the diabetic brain. CONCLUSIONS/INTERPRETATION We identified a novel effect of losartan in the nervous system that may be implemented to alleviate symptoms of diabetes-associated depression. These findings explore a new therapeutic horizon for ARBs as possible antidepressants and suggest that BDNF could be a target of future drug development in diabetes-induced complications.
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Affiliation(s)
- Lilla Lenart
- 1st Department of Pediatrics, Semmelweis University, Bókay János u. 53-54, Budapest, 1083, Hungary
- MTA-SE Lendület Diabetes Research Group, Budapest, Hungary
| | - Dora B Balogh
- 1st Department of Pediatrics, Semmelweis University, Bókay János u. 53-54, Budapest, 1083, Hungary
- MTA-SE Lendület Diabetes Research Group, Budapest, Hungary
| | - Nikolett Lenart
- "Momentum" Laboratory of Neuroimmunology, IEM HAS, Szigony u. 43, Budapest, 1083, Hungary
| | - Adrienn Barczi
- 1st Department of Pediatrics, Semmelweis University, Bókay János u. 53-54, Budapest, 1083, Hungary
| | - Adam Hosszu
- 1st Department of Pediatrics, Semmelweis University, Bókay János u. 53-54, Budapest, 1083, Hungary
- MTA-SE Lendület Diabetes Research Group, Budapest, Hungary
| | | | - Judit Hodrea
- 1st Department of Pediatrics, Semmelweis University, Bókay János u. 53-54, Budapest, 1083, Hungary
- MTA-SE Lendület Diabetes Research Group, Budapest, Hungary
| | - Attila J Szabo
- 1st Department of Pediatrics, Semmelweis University, Bókay János u. 53-54, Budapest, 1083, Hungary
- MTA-SE Pediatrics and Nephrology Research Group, Budapest, Hungary
| | - Krisztian Szigeti
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Adam Denes
- "Momentum" Laboratory of Neuroimmunology, IEM HAS, Szigony u. 43, Budapest, 1083, Hungary.
| | - Andrea Fekete
- 1st Department of Pediatrics, Semmelweis University, Bókay János u. 53-54, Budapest, 1083, Hungary.
- MTA-SE Lendület Diabetes Research Group, Budapest, Hungary.
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Hermann DM, Kleinschnitz C. Modeling Vascular Risk Factors for the Development of Ischemic Stroke Therapies. Stroke 2019; 50:1310-1317. [DOI: 10.1161/strokeaha.118.024673] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Dirk M. Hermann
- From the Department of Neurology, University Hospital Essen, Germany
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Ouk T, Potey C, Maestrini I, Petrault M, Mendyk AM, Leys D, Bordet R, Gautier S. Neutrophils in tPA-induced hemorrhagic transformations: Main culprit, accomplice or innocent bystander? Pharmacol Ther 2019; 194:73-83. [DOI: 10.1016/j.pharmthera.2018.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Shan BS, Mogi M, Iwanami J, Bai HY, Kan-No H, Higaki A, Min LJ, Horiuchi M. Attenuation of stroke damage by angiotensin II type 2 receptor stimulation via peroxisome proliferator-activated receptor-gamma activation. Hypertens Res 2018; 41:839-848. [PMID: 30089862 DOI: 10.1038/s41440-018-0082-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 07/01/2018] [Accepted: 07/04/2018] [Indexed: 11/09/2022]
Abstract
The brain renin-angiotensin system plays a crucial role in ischemic stroke. It is known that stimulation of the angiotensin II type 2 (AT2) receptor protects against ischemic brain injury. We recently demonstrated that AT2 receptor stimulation by compound 21 (C21), a direct AT2 receptor agonist, inhibited vascular intimal proliferation with activation of peroxisome proliferator-activated receptor-gamma (PPAR-γ). However, whether direct AT2 receptor stimulation protects against ischemic brain injury via PPAR-γ activation is still unknown. 8-week-old male C57BL/6 J mice were subjected to middle cerebral artery (MCA) occlusion. 2 weeks before MCA occlusion, they were administered C21 with or without GW9662, a PPAR-γ antagonist. Neurologic deficit, ischemic size, superoxide anion, superoxide dismutase (SOD) activity, expression of NADPH subunits and blood brain barrier (BBB) stabilization were assessed 24 h after MCA occlusion. Cerebral blood flow (CBF) was measured in the core and periphery of the MCA territory before, immediately after, 1 h and 24 h after MCA occlusion. Treatment with C21 markedly decreased the neurologic deficit and ischemic size with an increase in CBF, SOD activity and BBB stabilization genes compared with the non-treated group. Co-administration of GW9662 partially attenuated this protective effect of C21 on neurologic deficit and ischemic size via an increase in superoxide anion production and a decrease of SOD activity and BBB stabilization genes, while GW9662 treatment alone had no significant effect on neurologic deficit and ischemic size. These results suggest that direct AT2 receptor stimulation has a preventive effect on stroke-induced brain injury partly due to activation of PPAR-γ.
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Affiliation(s)
- Bao-Shuai Shan
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Matsuyama, Japan
| | - Masaki Mogi
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Matsuyama, Japan.
| | - Jun Iwanami
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Matsuyama, Japan
| | - Hui-Yu Bai
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Matsuyama, Japan
| | - Harumi Kan-No
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Matsuyama, Japan
| | - Akinori Higaki
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Matsuyama, Japan.,Department of Cardiology, Pulmonology, Hypertension and Nephrology, Ehime University, Graduate School of Medicine, Matsuyama, Japan
| | - Li-Juan Min
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Matsuyama, Japan
| | - Masatsugu Horiuchi
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Matsuyama, Japan
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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: 3.1] [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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14
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Gebre AK, Altaye BM, Atey TM, Tuem KB, Berhe DF. Targeting Renin-Angiotensin System Against Alzheimer's Disease. Front Pharmacol 2018; 9:440. [PMID: 29760662 PMCID: PMC5937164 DOI: 10.3389/fphar.2018.00440] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/13/2018] [Indexed: 01/01/2023] Open
Abstract
Renin Angiotensin System (RAS) is a hormonal system that regulates blood pressure and fluid balance through a coordinated action of renal, cardiovascular, and central nervous systems. In addition to its hemodynamic regulatory role, RAS involves in many brain activities, including memory acquisition and consolidation. This review has summarized the involvement of RAS in the pathology of Alzheimer’s disease (AD), and the outcomes of treatment with RAS inhibitors. We have discussed the effect of brain RAS in the amyloid plaque (Aβ) deposition, oxidative stress, neuroinflammation, and vascular pathology which are directly and indirectly associated with AD. Angiotensin II (AngII) via AT1 receptor is reported to increase brain Aβ level via different mechanisms including increasing amyloid precursor protein (APP) mRNA, β-secretase activity, and presenilin expression. Similarly, it was associated with tau phosphorylation, and reactive oxygen species generation. However, these effects are counterbalanced by Ang II mediated AT2 signaling. The protective effect observed with angiotensin receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs) could be as the result of inhibition of Ang II signaling. ARBs also offer additional benefit by shifting the effect of Ang II toward AT2 receptor. To conclude, targeting RAS in the brain may benefit patients with AD though it still requires further in depth understanding.
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Affiliation(s)
- Abadi Kahsu Gebre
- Department of Pharmacology and Toxicology, School of Pharmacy, College of Health Sciences, Mekelle University, Mekelle, Ethiopia
| | - Birhanetensay Masresha Altaye
- Department of Pharmacology and Toxicology, School of Pharmacy, College of Health Sciences, Mekelle University, Mekelle, Ethiopia
| | - Tesfay Mehari Atey
- Clinical Pharmacy Unit, School of Pharmacy, College of Health Sciences, Mekelle University, Mekelle, Ethiopia
| | - Kald Beshir Tuem
- Department of Pharmacology and Toxicology, School of Pharmacy, College of Health Sciences, Mekelle University, Mekelle, Ethiopia
| | - Derbew Fikadu Berhe
- Department of Pharmacology and Toxicology, School of Pharmacy, College of Health Sciences, Mekelle University, Mekelle, Ethiopia
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15
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Rehni AK, Liu A, Perez-Pinzon MA, Dave KR. Diabetic aggravation of stroke and animal models. Exp Neurol 2017; 292:63-79. [PMID: 28274862 PMCID: PMC5400679 DOI: 10.1016/j.expneurol.2017.03.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 02/03/2017] [Accepted: 03/03/2017] [Indexed: 12/16/2022]
Abstract
Cerebral ischemia in diabetics results in severe brain damage. Different animal models of cerebral ischemia have been used to study the aggravation of ischemic brain damage in the diabetic condition. Since different disease conditions such as diabetes differently affect outcome following cerebral ischemia, the Stroke Therapy Academic Industry Roundtable (STAIR) guidelines recommends use of diseased animals for evaluating neuroprotective therapies targeted to reduce cerebral ischemic damage. The goal of this review is to discuss the technicalities and pros/cons of various animal models of cerebral ischemia currently being employed to study diabetes-related ischemic brain damage. The rational use of such animal systems in studying the disease condition may better help evaluate novel therapeutic approaches for diabetes related exacerbation of ischemic brain damage.
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Affiliation(s)
- Ashish K Rehni
- Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Allen Liu
- Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Miguel A Perez-Pinzon
- Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Kunjan R Dave
- Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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16
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Labandeira-Garcia JL, Rodríguez-Perez AI, Garrido-Gil P, Rodriguez-Pallares J, Lanciego JL, Guerra MJ. Brain Renin-Angiotensin System and Microglial Polarization: Implications for Aging and Neurodegeneration. Front Aging Neurosci 2017; 9:129. [PMID: 28515690 PMCID: PMC5413566 DOI: 10.3389/fnagi.2017.00129] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/18/2017] [Indexed: 12/12/2022] Open
Abstract
Microglia can transform into proinflammatory/classically activated (M1) or anti-inflammatory/alternatively activated (M2) phenotypes following environmental signals related to physiological conditions or brain lesions. An adequate transition from the M1 (proinflammatory) to M2 (immunoregulatory) phenotype is necessary to counteract brain damage. Several factors involved in microglial polarization have already been identified. However, the effects of the brain renin-angiotensin system (RAS) on microglial polarization are less known. It is well known that there is a “classical” circulating RAS; however, a second RAS (local or tissue RAS) has been observed in many tissues, including brain. The locally formed angiotensin is involved in local pathological changes of these tissues and modulates immune cells, which are equipped with all the components of the RAS. There are also recent data showing that brain RAS plays a major role in microglial polarization. Level of microglial NADPH-oxidase (Nox) activation is a major regulator of the shift between M1/proinflammatory and M2/immunoregulatory microglial phenotypes so that Nox activation promotes the proinflammatory and inhibits the immunoregulatory phenotype. Angiotensin II (Ang II), via its type 1 receptor (AT1), is a major activator of the NADPH-oxidase complex, leading to pro-oxidative and pro-inflammatory effects. However, these effects are counteracted by a RAS opposite arm constituted by Angiotensin II/AT2 receptor signaling and Angiotensin 1–7/Mas receptor (MasR) signaling. In addition, activation of prorenin-renin receptors may contribute to activation of the proinflammatory phenotype. Aged brains showed upregulation of AT1 and downregulation of AT2 receptor expression, which may contribute to a pro-oxidative pro-inflammatory state and the increase in neuron vulnerability. Several recent studies have shown interactions between the brain RAS and different factors involved in microglial polarization, such as estrogens, Rho kinase (ROCK), insulin-like growth factor-1 (IGF-1), tumor necrosis factor α (TNF)-α, iron, peroxisome proliferator-activated receptor gamma, and toll-like receptors (TLRs). Metabolic reprogramming has recently been involved in the regulation of the neuroinflammatory response. Interestingly, we have recently observed a mitochondrial RAS, which is altered in aged brains. In conclusion, dysregulation of brain RAS plays a major role in aging-related changes and neurodegeneration by exacerbation of oxidative
stress (OS) and neuroinflammation, which may be attenuated by pharmacological manipulation of RAS components.
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Affiliation(s)
- Jose L Labandeira-Garcia
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de CompostelaSantiago de Compostela, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED)Madrid, Spain
| | - Ana I Rodríguez-Perez
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de CompostelaSantiago de Compostela, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED)Madrid, Spain
| | - Pablo Garrido-Gil
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de CompostelaSantiago de Compostela, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED)Madrid, Spain
| | - Jannette Rodriguez-Pallares
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de CompostelaSantiago de Compostela, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED)Madrid, Spain
| | - Jose L Lanciego
- Networking Research Center on Neurodegenerative Diseases (CIBERNED)Madrid, Spain.,Neurosciences Division, Center for Applied Medical Research (CIMA), University of NavarraPamplona, Spain
| | - Maria J Guerra
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de CompostelaSantiago de Compostela, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED)Madrid, Spain
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Nakagawa T, Hasegawa Y, Uekawa K, Senju S, Nakagata N, Matsui K, Kim-Mitsuyama S. Transient Mild Cerebral Ischemia Significantly Deteriorated Cognitive Impairment in a Mouse Model of Alzheimer's Disease via Angiotensin AT1 Receptor. Am J Hypertens 2017; 30:141-150. [PMID: 27572961 DOI: 10.1093/ajh/hpw099] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 07/21/2016] [Accepted: 08/03/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Ischemic stroke is suggested to be potentially associated with cognitive impairment in Alzheimer's disease (AD). We hypothesized that cerebral ischemia deteriorates cognitive impairment in AD, through angiotensin II. METHODS We used 5XFAD mouse, a model of AD with vascular and cerebral amyloid-β deposition. Transient cerebral ischemia of mice was induced by bilateral common carotid artery occlusion (BCCAO) for 17 minutes. The posttreatment with olmesartan, an ARB, or vehicle was started at 24 hours after BCCAO and was performed for 5 weeks. Experimental mice consisted of 5 groups: (i) wild-type mice, (ii) wild-type mice with BCCAO, (iii) 5XFAD mice, (iv) 5XFAD mice with BCCAO, (v) 5XFAD mice with BCCAO and olmesartan postadministration. RESULTS BCCAO in 5XFAD caused greater escape latency (P < 0.01) on water maze test than that in wild type, indicating that transient brief cerebral ischemia enhanced cognitive decline in 5XFAD mice. Posttreatment with olmesartan significantly reduced escape latency (P < 0.01) on water maze test, retention trial latency (P < 0.05) on passive avoidance test, and retention time of outer zone (P < 0.01) on open-field test in 5XFAD subjected to BCCAO. This protective effect of olmesartan against cognitive impairment in 5XFAD with BCCAO was associated with the protection of neuron and attenuation of oxidative stress in hippocampus and the suppression of blood-brain barrier disruption. CONCLUSIONS We obtained the evidence that transient brief cerebral ischemia deteriorated cognitive impairment in AD model through AT1 receptor.
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Affiliation(s)
- Takashi Nakagawa
- Departments of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Yu Hasegawa
- Departments of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Ken Uekawa
- Departments of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Satoru Senju
- Department of Immunogenetics, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Naomi Nakagata
- Division of Reproductive Engineering, Center for Animal Resources and Development, Kumamoto University, Kumamoto, Japan
| | - Kunihiko Matsui
- Department of General and Community Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Shokei Kim-Mitsuyama
- Departments of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan;
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18
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Zhou J, Burns MP, Huynh L, Villapol S, Taub DD, Saavedra JM, Blackman MR. Temporal Changes in Cortical and Hippocampal Expression of Genes Important for Brain Glucose Metabolism Following Controlled Cortical Impact Injury in Mice. Front Endocrinol (Lausanne) 2017; 8:231. [PMID: 28955302 PMCID: PMC5601958 DOI: 10.3389/fendo.2017.00231] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/24/2017] [Indexed: 02/06/2023] Open
Abstract
Traumatic brain injury (TBI) causes transient increases and subsequent decreases in brain glucose utilization. The underlying molecular pathways are orchestrated processes and poorly understood. In the current study, we determined temporal changes in cortical and hippocampal expression of genes important for brain glucose/lactate metabolism and the effect of a known neuroprotective drug telmisartan on the expression of these genes after experimental TBI. Adult male C57BL/6J mice (n = 6/group) underwent sham or unilateral controlled cortical impact (CCI) injury. Their ipsilateral and contralateral cortex and hippocampus were collected 6 h, 1, 3, 7, 14, 21, and 28 days after injury. Expressions of several genes important for brain glucose utilization were determined by qRT-PCR. In results, (1) mRNA levels of three key enzymes in glucose metabolism [hexo kinase (HK) 1, pyruvate kinase, and pyruvate dehydrogenase (PDH)] were all increased 6 h after injury in the contralateral cortex, followed by decreases at subsequent times in the ipsilateral cortex and hippocampus; (2) capillary glucose transporter Glut-1 mRNA increased, while neuronal glucose transporter Glut-3 mRNA decreased, at various times in the ipsilateral cortex and hippocampus; (3) astrocyte lactate transporter MCT-1 mRNA increased, whereas neuronal lactate transporter MCT-2 mRNA decreased in the ipsilateral cortex and hippocampus; (4) HK2 (an isoform of hexokinase) expression increased at all time points in the ipsilateral cortex and hippocampus. GPR81 (lactate receptor) mRNA increased at various time points in the ipsilateral cortex and hippocampus. These temporal alterations in gene expression corresponded closely to the patterns of impaired brain glucose utilization reported in both TBI patients and experimental TBI rodents. The observed changes in hippocampal gene expression were delayed and prolonged, when compared with those in the cortex. The patterns of alterations were specific to different brain regions and exhibited different recovery periods following TBI. Oral administration of telmisartan (1 mg/kg, for 7 days, n = 10 per group) ameliorated cortical or hippocampal mRNA for Glut-1/3, MCT-1/2 and PDH in CCI mice. These data provide molecular evidence for dynamic alteration of multiple critical factors in brain glucose metabolism post-TBI and can inform further research for treating brain metabolic disorders post-TBI.
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Affiliation(s)
- June Zhou
- Research Service, Washington DC VA Medical Center, Washington, DC, United States
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine, Washington, DC, United States
- *Correspondence: June Zhou,
| | - Mark P. Burns
- Department of Neuroscience, Georgetown University School of Medicine, Washington, DC, United States
| | - Linda Huynh
- Research Service, Washington DC VA Medical Center, Washington, DC, United States
| | - Sonia Villapol
- Department of Neuroscience, Georgetown University School of Medicine, Washington, DC, United States
| | - Daniel D. Taub
- Translational Medicine Section, Washington DC VA Medical Center, Washington, DC, United States
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University School of Medicine, Washington, DC, United States
| | - Juan M. Saavedra
- Department of Pharmacology and Physiology, Georgetown University School of Medicine, Washington, DC, United States
| | - Marc R. Blackman
- Research Service, Washington DC VA Medical Center, Washington, DC, United States
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine, Washington, DC, United States
- Department of Medicine George Washington University School of Medicine, Washington, DC, United States
- Department of Medicine, Georgetown University School of Medicine, Washington, DC, United States
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19
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Labandeira-Garcia JL, Rodriguez-Perez AI, Valenzuela R, Costa-Besada MA, Guerra MJ. Menopause and Parkinson's disease. Interaction between estrogens and brain renin-angiotensin system in dopaminergic degeneration. Front Neuroendocrinol 2016; 43:44-59. [PMID: 27693730 DOI: 10.1016/j.yfrne.2016.09.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 09/26/2016] [Accepted: 09/27/2016] [Indexed: 02/07/2023]
Abstract
The neuroprotective effects of menopausal hormonal therapy in Parkinson's disease (PD) have not yet been clarified, and it is controversial whether there is a critical period for neuroprotection. Studies in animal models and clinical and epidemiological studies indicate that estrogens induce dopaminergic neuroprotection. Recent studies suggest that inhibition of the brain renin-angiotensin system (RAS) mediates the effects of estrogens in PD models. In the substantia nigra, ovariectomy induces a decrease in levels of estrogen receptor-α (ER-α) and increases angiotensin activity, NADPH-oxidase activity and expression of neuroinflammatory markers, which are regulated by estrogen replacement therapy. There is a critical period for the neuroprotective effect of estrogen replacement therapy, and local ER-α and RAS play a major role. Astrocytes play a major role in ER-α-induced regulation of local RAS, but neurons and microglia are also involved. Interestingly, treatment with angiotensin receptor antagonists after the critical period induced neuroprotection.
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Affiliation(s)
- Jose L Labandeira-Garcia
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain.
| | - Ana I Rodriguez-Perez
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Rita Valenzuela
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Maria A Costa-Besada
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Maria J Guerra
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
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20
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Simeone TA, Matthews SA, Samson KK, Simeone KA. Regulation of brain PPARgamma2 contributes to ketogenic diet anti-seizure efficacy. Exp Neurol 2016; 287:54-64. [PMID: 27527983 DOI: 10.1016/j.expneurol.2016.08.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 08/05/2016] [Accepted: 08/11/2016] [Indexed: 12/23/2022]
Abstract
The ketogenic diet (KD) is an effective therapy primarily used in pediatric patients whom are refractory to current anti-seizure medications. The mechanism of the KD is not completely understood, but is thought to involve anti-inflammatory and anti-oxidant processes. The nutritionally-regulated transcription factor peroxisome proliferator activated receptor gamma, PPARγ, regulates genes involved in anti-inflammatory and anti-oxidant pathways. Moreover, endogenous ligands of PPARγ include fatty acids suggesting a potential role in the effects of the KD. Here, we tested the hypothesis that PPARγ contributes to the anti-seizure efficacy of the KD. We found that the KD increased nuclear protein content of the PPARγ2 splice variant by 2-4 fold (P<0.05) in brain homogenates from wild-type (WT) and epileptic Kv1.1 knockout (KO) mice, while not affecting PPARγ1. The KD reduced the frequency of seizures in Kv1.1KO mice by ~70% (P<0.01). GW9662, a PPARγ antagonist, prevented KD-mediated changes in PPARγ2 expression and prevented the anti-seizure efficacy of the KD in Kv1.1KO mice. Further supporting the association of PPARγ2 in mediating KD actions, the KD significantly prolonged the latency to flurothyl-induced seizure in WT mice by ~20-35% (P<0.01), but was ineffective in PPARγ2KO mice and neuron-specific PPARγKO mice. Finally, administering the PPARγ agonist pioglitazone increased PPARγ2 expression by 2-fold (P<0.01) and reduced seizures in Kv1.1KO mice by ~80% (P<0.01). Our findings implicate brain PPARγ2 among the mechanisms by which the KD reduces seizures and strongly support the development of PPARγ2 as a therapeutic target for severe, refractory epilepsy.
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Affiliation(s)
- Timothy A Simeone
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE 68174, USA.
| | - Stephanie A Matthews
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE 68174, USA
| | - Kaeli K Samson
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE 68174, USA
| | - Kristina A Simeone
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE 68174, USA
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Michel MC, Brunner HR, Foster C, Huo Y. Angiotensin II type 1 receptor antagonists in animal models of vascular, cardiac, metabolic and renal disease. Pharmacol Ther 2016; 164:1-81. [PMID: 27130806 DOI: 10.1016/j.pharmthera.2016.03.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 03/30/2016] [Indexed: 02/07/2023]
Abstract
We have reviewed the effects of angiotensin II type 1 receptor antagonists (ARBs) in various animal models of hypertension, atherosclerosis, cardiac function, hypertrophy and fibrosis, glucose and lipid metabolism, and renal function and morphology. Those of azilsartan and telmisartan have been included comprehensively whereas those of other ARBs have been included systematically but without intention of completeness. ARBs as a class lower blood pressure in established hypertension and prevent hypertension development in all applicable animal models except those with a markedly suppressed renin-angiotensin system; blood pressure lowering even persists for a considerable time after discontinuation of treatment. This translates into a reduced mortality, particularly in models exhibiting marked hypertension. The retrieved data on vascular, cardiac and renal function and morphology as well as on glucose and lipid metabolism are discussed to address three main questions: 1. Can ARB effects on blood vessels, heart, kidney and metabolic function be explained by blood pressure lowering alone or are they additionally directly related to blockade of the renin-angiotensin system? 2. Are they shared by other inhibitors of the renin-angiotensin system, e.g. angiotensin converting enzyme inhibitors? 3. Are some effects specific for one or more compounds within the ARB class? Taken together these data profile ARBs as a drug class with unique properties that have beneficial effects far beyond those on blood pressure reduction and, in some cases distinct from those of angiotensin converting enzyme inhibitors. The clinical relevance of angiotensin receptor-independent effects of some ARBs remains to be determined.
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Affiliation(s)
- Martin C Michel
- Dept. Pharmacology, Johannes Gutenberg University, Mainz, Germany; Dept. Translational Medicine & Clinical Pharmacology, Boehringer Ingelheim, Ingelheim, Germany.
| | | | - Carolyn Foster
- Retiree from Dept. of Research Networking, Boehringer Ingelheim Pharmaceuticals Inc., Ridgefield, CT, USA
| | - Yong Huo
- Dept. Cardiology & Heart Center, Peking University First Hospital, Beijing, PR China
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Systematic review of survival time in experimental mouse stroke with impact on reliability of infarct estimation. J Neurosci Methods 2016; 261:10-8. [PMID: 26620203 DOI: 10.1016/j.jneumeth.2015.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/24/2015] [Accepted: 11/17/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND Stroke is the second most common cause of death worldwide. Only one treatment for acute ischemic stroke is currently available, thrombolysis with rt-PA, but it is limited in its use. Many efforts have been invested in order to find additive treatments, without success. A multitude of reasons for the translational problems from mouse experimental stroke to clinical trials probably exists, including infarct size estimations around the peak time of edema formation. Furthermore, edema is a more prominent feature of stroke in mice than in humans, because of the tendency to produce larger infarcts with more substantial edema. PURPOSE This paper will give an overview of previous studies of experimental mouse stroke, and correlate survival time to peak time of edema formation. Furthermore, investigations of whether the included studies corrected the infarct measurements for edema and a comparison of correction methods will be discussed. METHOD Relevant terms were searched in the National Library of Medicine PubMed database. A method for classification of infarct measurement methods was made using a naming convention. CONCLUSION Our study shows that infarct size estimations are often performed around the peak time of edema, with a median of 24h. Most studies do consider edema formation, however, there is no consensus on what method to use to correct for edema. Furthermore, investigations into neuroprotective drugs should use longer survival times to ensure completion of the investigated process. Our findings indicate a need for more research in this area, and establishment of common correction methodology.
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Prathab Balaji S, Vijay Chand C, Justin A, Ramanathan M. Telmisartan mediates anti-inflammatory and not cognitive function through PPAR-γ agonism via SARM and MyD88 signaling. Pharmacol Biochem Behav 2015; 137:60-8. [DOI: 10.1016/j.pbb.2015.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/03/2015] [Accepted: 08/05/2015] [Indexed: 10/23/2022]
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Farag E, Maheshwari K, Morgan J, Sakr Esa WA, Doyle DJ. An update of the role of renin angiotensin in cardiovascular homeostasis. Anesth Analg 2015; 120:275-92. [PMID: 25602448 DOI: 10.1213/ane.0000000000000528] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The renin angiotensin system (RAS) is thought to be the body's main vasoconstrictor system, with physiological effects mediated via the interaction of angiotensin II with angiotensin I receptors (the "classic" RAS model). However, since the discovery of the heptapeptide angiotensin 1-7 and the development of the concept of the "alternate" RAS system, with its ability to reduce arterial blood pressure, our understanding of this physiologic system has changed dramatically. In this review, we focus on the newly discovered functions of the RAS, particularly the potential clinical significance of these developments, especially in the realm of new pharmacologic interventions for treating cardiovascular disease.
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Affiliation(s)
- Ehab Farag
- From the Departments of *General Anesthesia and †Outcomes Research, Cleveland Clinic, Cleveland, Ohio; ‡Anesthesiology Institute, Cleveland Clinic, Cleveland, Ohio; and §Cleveland Clinic Lerner College of Medicine of Case Western Reserve University/Department of General Anesthesia, Cleveland Clinic, Cleveland, Ohio
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Yuksel TN, Halici Z, Demir R, Cakir M, Calikoglu C, Ozdemir G, Unal D. Investigation of the effect of telmisartan on experimentally induced peripheral nerve injury in rats. Int J Neurosci 2014; 125:464-73. [PMID: 25069044 DOI: 10.3109/00207454.2014.948115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIM The aim of this study was to investigate the effects of telmisartan on nerve healing in a rat peripheral nerve injury model. MATERIAL AND METHOD Thirty adult male Wistar albino rats were divided into five groups: healthy, axonotmesis, anastomosis, axonotmesis+10 mg/kg telmisartan and anastomosis+10 mg/kg telmisartan. Walking track analyses were performed 4 weeks after the surgery. The right sciatic nerves of all the animals were examined histopathologically, stereologically and molecularly. RESULTS Many badly damaged axons were detected in the axonotmesis group, in addition to enlarged spaces between the axons. In the anastomosis group, both ir- regular and degenerated axons at different severities were observed. The sections of the telmisartan group after the axonotmesis were similar to those of the healthy group. The sections of the telmisartan group after the anastomosis were similar to those of the healthy group and the telmisartan group after the axonotmesis. Interleukin-1 beta (IL-1β) gene expression increased in both the axonotmesis and the anastomosis groups when compared with the healthy group. Telmisartan had a significant down-regulatory effect on IL-1β expression. Caspase-3 mRNA expression was significantly increased in the anastomosis group, and the administration of telmisartan in this group significantly decreased this rise in caspase-3 mRNA expression. As a functional outcome, telmisartan also increased the walking distance of the rats after axonotmesis and anastomosis. CONCLUSION The histopathological, stereological, functional and molecular data suggest that telmisartan improves nerve regeneration in peripheral nerve injuries by inhibiting inflammatory cytokine IL-1β and apoptotic caspase-3.
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Min LJ, Mogi M, Tsukuda K, Jing F, Ohshima K, Nakaoka H, Kan-No H, Wang XL, Chisaka T, Bai HY, Iwanami J, Horiuchi M. Direct stimulation of angiotensin II type 2 receptor initiated after stroke ameliorates ischemic brain damage. Am J Hypertens 2014; 27:1036-44. [PMID: 24572705 DOI: 10.1093/ajh/hpu015] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Stroke is a leading cause of death and disability; however, meta-analysis of randomized controlled trials of blood pressure-lowering drugs in acute stroke has shown no definite evidence of a beneficial effect on functional outcome. Accumulating evidence suggests that angiotensin II type 1 receptor blockade with angiotensin II type 2 (AT2) receptor stimulation could contribute to protection against ischemic brain damage. We examined the possibility that direct AT2 receptor stimulation by compound 21 (C21) initiated even after stroke can prevent ischemic brain damage. METHODS Stroke was induced by middle cerebral artery (MCA) occlusion, and the area of cerebral infarction was measured by magnetic resonant imaging. C21 (10 µg/kg/day) treatment was initiated immediately after MCA occlusion by intraperitoneal injection followed by treatment with C21 once daily. RESULTS We observed that ischemic area was enlarged in a time dependent fashion and decreased on day 5 after MCA occlusion. Treatment with C21 initiated after MCA occlusion significantly reduced the ischemic area, with improvement of neurological deficit in a time-dependent manner without affecting blood pressure. The decrease of cerebral blood flow after MCA occlusion was also ameliorated by C21 treatment. Moreover, treatment with C21 significantly attenuated superoxide anion production and expression of proinflammatory cytokines, monocyte chemoattractant protein 1, and tumor necrosis factor α. Interestingly, C21 administration significantly decreased blood-brain barrier permeability and cerebral edema on the ischemic side. CONCLUSIONS These results provide new evidence that direct AT2 receptor stimulation with C21 is a novel therapeutic approach to prevent ischemic brain damage after acute stroke.
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Affiliation(s)
- Li-Juan Min
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Masaki Mogi
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Kana Tsukuda
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Fei Jing
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Kousei Ohshima
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Hirotomo Nakaoka
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Harumi Kan-No
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Xiao-Li Wang
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Toshiyuki Chisaka
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Hui-Yu Bai
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Jun Iwanami
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan
| | - Masatsugu Horiuchi
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University Graduate School of Medicine, Tohon, Ehime, Japan.
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Labandeira-García JL, Garrido-Gil P, Rodriguez-Pallares J, Valenzuela R, Borrajo A, Rodríguez-Perez AI. Brain renin-angiotensin system and dopaminergic cell vulnerability. Front Neuroanat 2014; 8:67. [PMID: 25071471 PMCID: PMC4086395 DOI: 10.3389/fnana.2014.00067] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 06/24/2014] [Indexed: 01/11/2023] Open
Abstract
Although the renin-angiotensin system (RAS) was classically considered as a circulating system that regulates blood pressure, many tissues are now known to have a local RAS. Angiotensin, via type 1 receptors, is a major activator of the NADPH-oxidase complex, which mediates several key events in oxidative stress (OS) and inflammatory processes involved in the pathogenesis of major aging-related diseases. Several studies have demonstrated the presence of RAS components in the basal ganglia, and particularly in the nigrostriatal system. In the nigrostriatal system, RAS hyperactivation, via NADPH-oxidase complex activation, exacerbates OS and the microglial inflammatory response and contributes to progression of dopaminergic degeneration, which is inhibited by angiotensin receptor blockers and angiotensin converting enzyme (ACE) inhibitors. Several factors may induce an increase in RAS activity in the dopaminergic system. A decrease in dopaminergic activity induces compensatory upregulation of local RAS function in both dopaminergic neurons and glia. In addition to its role as an essential neurotransmitter, dopamine may also modulate microglial inflammatory responses and neuronal OS via RAS. Important counterregulatory interactions between angiotensin and dopamine have also been observed in several peripheral tissues. Neurotoxins and proinflammatory factors may also act on astrocytes to induce an increase in RAS activity, either independently of or before the loss of dopamine. Consistent with a major role of RAS in dopaminergic vulnerability, increased RAS activity has been observed in the nigra of animal models of aging, menopause and chronic cerebral hypoperfusion, which also showed higher dopaminergic vulnerability. Manipulation of the brain RAS may constitute an effective neuroprotective strategy against dopaminergic vulnerability and progression of Parkinson's disease.
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Affiliation(s)
- Jose L Labandeira-García
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, Faculty of Medicine, University of Santiago de Compostela Santiago de Compostela, Spain ; Networking Research Center on Neurodegenerative Diseases (CIBERNED) Madrid, Spain
| | - Pablo Garrido-Gil
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, Faculty of Medicine, University of Santiago de Compostela Santiago de Compostela, Spain ; Networking Research Center on Neurodegenerative Diseases (CIBERNED) Madrid, Spain
| | - Jannette Rodriguez-Pallares
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, Faculty of Medicine, University of Santiago de Compostela Santiago de Compostela, Spain ; Networking Research Center on Neurodegenerative Diseases (CIBERNED) Madrid, Spain
| | - Rita Valenzuela
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, Faculty of Medicine, University of Santiago de Compostela Santiago de Compostela, Spain ; Networking Research Center on Neurodegenerative Diseases (CIBERNED) Madrid, Spain
| | - Ana Borrajo
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, Faculty of Medicine, University of Santiago de Compostela Santiago de Compostela, Spain ; Networking Research Center on Neurodegenerative Diseases (CIBERNED) Madrid, Spain
| | - Ana I Rodríguez-Perez
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, Faculty of Medicine, University of Santiago de Compostela Santiago de Compostela, Spain ; Networking Research Center on Neurodegenerative Diseases (CIBERNED) Madrid, Spain
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Matsumura T, Taketa K, Shimoda S, Araki E. Thiazolidinedione-independent activation of peroxisome proliferator-activated receptor γ is a potential target for diabetic macrovascular complications. J Diabetes Investig 2014; 3:11-23. [PMID: 24843540 PMCID: PMC4014927 DOI: 10.1111/j.2040-1124.2011.00182.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Macrovascular complications are responsible for the high morbidity and mortality in patients with diabetes. Peroxisome proliferator‐activated receptor γ (PPARγ) plays a central role in the process of adipocyte differentiation and insulin sensitization, and also possesses anti‐atherogenic effects. Recently, some statins, angiotensin II type 1 receptor blockers and calcium channel blockers have been reported to activate PPARγ. However, the impact of PPARγ activation on diabetic macrovascular complications is not fully understood. It has been reported that the activation of PPARγ by thiazolidinediones induces anti‐atherogenic effects in vascular cells, including monocytes/macrophages, endothelial cells and smooth muscle cells, in atherosclerotic animal models and in clinical studies. We have reported that hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), which are used for treatment of hypercholesterolemia, activate PPARγ and mediate anti‐atherogenic effects through PPARγ activation in macrophages. Also, telmisartan, an angiotensin type I receptor blocker, has been reported to have anti‐atherogenic effects through PPARγ activation. Furthermore, we have reported that nifedipine, a dihydropyridine calcium channel blocker, can activate PPARγ, thereby mediating anti‐atherogenic effects in macrophages. Therefore, statin therapy and part of anti‐hypertensive therapy might produce beneficial effects through PPARγ activation in hypercholesterolemic and/or hypertensive patients with diabetes, and PPARγ might be a therapeutic target for diabetic macrovascular complications. In the present review, we focus on the anti‐atherogenic effects of PPARγ and suggest potential therapeutic approaches to prevent diabetic macrovascular complications. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00182.x, 2012)
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Affiliation(s)
- Takeshi Matsumura
- Department of Metabolic Medicine, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kayo Taketa
- Department of Metabolic Medicine, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Seiya Shimoda
- Department of Metabolic Medicine, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Eiichi Araki
- Department of Metabolic Medicine, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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Telmisartan protects central neurons against nutrient deprivation-induced apoptosis in vitro through activation of PPARγ and the Akt/GSK-3β pathway. Acta Pharmacol Sin 2014; 35:727-37. [PMID: 24793312 DOI: 10.1038/aps.2013.199] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/30/2013] [Indexed: 12/15/2022]
Abstract
AIM To determine whether angiotensin II receptor blockers (ARBs) could protect central neurons against nutrient deprivation-induced apoptosis in vitro and to elucidate the underlying mechanisms. METHODS Primary rat cerebellar granule cells (CGCs) underwent B27 (a serum substitute) deprivation for 24 h to induce neurotoxicity, and cell viability was analyzed using LDH assay and WST-1 assay. DNA laddering assay and TUNEL assay were used to detect cell apoptosis. The expression of caspase-3 and Bcl-2, and the phosphorylation of Akt and GSK-3β were detected using Western blot analysis. AT1a mRNA expression was determined using RT-PCR analysis. RESULTS B27 deprivation significantly increased the apoptosis of CGCs, as demonstrated by LDH release, DNA laddering, caspase-3 activation and positive TUNEL staining. Pretreatment with 10 μmol/L ARBs (telmisartan, candesartan or losartan) partially blocked B27 deprivation-induced apoptosis of CGCs with telmisartan being the most effective one. B27 deprivation markedly increased the expression of AT1a receptor in CGCs, inhibited Akt and GSK-3β activation, decreased Bcl-2 level, and activated caspase-3, which were reversed by pretreatment with 1 μmol/L telmisartan. In addition, pretreatment with 10 μmol/L PPARγ agonist pioglitazone was more effective in protecting CGCs against B27 deprivation-induced apoptosis, whereas pretreatment with 20 μmol/L PPARγ antagonist GW9662 abolished all the effects of telmisartan in CGCs deprived of B27. CONCLUSION ARBs, in particular telmisartan, can protect the nutrient deprivation-induced apoptosis of CGCs in vitro through activation of PPARγ and the Akt/GSK-3β pathway.
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Chen J, Zhao Y, Chen S, Wang J, Xiao X, Ma X, Penchikala M, Xia H, Lazartigues E, Zhao B, Chen Y. Neuronal over-expression of ACE2 protects brain from ischemia-induced damage. Neuropharmacology 2014; 79:550-8. [PMID: 24440367 DOI: 10.1016/j.neuropharm.2014.01.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 12/10/2013] [Accepted: 01/06/2014] [Indexed: 01/17/2023]
Abstract
Angiotensin (Ang) II exaggerates cerebral injury in ischemic damage. Angiotensin-converting enzyme type 2 (ACE2) converts Ang II into Ang (1-7) and thus, may protect against the effects of Ang II. We hypothesized that neuronal ACE2 over-expression decreases ischemic stroke in mice with Ang II overproduction. Human renin and angiotensinogen double transgenic (RA) mice and RA mice with neuronal over-expression of ACE2 (SARA) were used for the study. The mean arterial pressure (MAP) was calculated from telemetry-recorded blood pressure (BP). SARA mice were infused peripherally with Norepinephrine to "clamp" the BP, or intracerebroventricularly-infused with a Mas receptor antagonist (A-779). Middle cerebral artery occlusion (MCAO) surgery was performed to induce permanent focal ischemic stroke. Cerebral blood flow (CBF) and neurological function were determined. Two days after surgery, brain samples were collected for various analyses. Results showed: 1) When compared to chronically hypertensive RA mice, SARA mice had lower basal MAP, less MCAO-induced infarct volume, and increased CBF, neurological function and cerebral microvascular density in the peri-infarct area; 2) These changes in SARA mice were not altered after MAP "clamping", but partially reversed by brain infusion of A-779; 3) Ang (1-7)/Ang II ratio, angiogenic factors, endothelial nitric oxide synthase (eNOS) expression and nitric oxide production were increased, whereas, NADPH oxidase subunits and reactive oxygen species were decreased in the brain of SARA mice. ACE2 protects brain from ischemic injury via the regulation of NADPH oxidase/eNOS pathways by changing Ang (1-7)/Ang II ratio, independently of MAP changes.
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Affiliation(s)
- Ji Chen
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA; Department of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China
| | - Yuhui Zhao
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Shuzhen Chen
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Jinju Wang
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Xiang Xiao
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Xiaotang Ma
- Department of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China
| | - Madhuri Penchikala
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Huijing Xia
- Department of Pharmacology & Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Eric Lazartigues
- Department of Pharmacology & Experimental Therapeutics and Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Bin Zhao
- Department of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China.
| | - Yanfang Chen
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA.
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Labandeira-Garcia JL, Rodriguez-Pallares J, Dominguez-Meijide A, Valenzuela R, Villar-Cheda B, Rodríguez-Perez AI. Dopamine-angiotensin interactions in the basal ganglia and their relevance for Parkinson's disease. Mov Disord 2013; 28:1337-42. [PMID: 23925977 DOI: 10.1002/mds.25614] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 04/29/2013] [Accepted: 06/26/2013] [Indexed: 01/08/2023] Open
Abstract
Renin-angiotensin systems are known to act in many tissues, for example, the blood vessel wall or kidney, where a close interaction between angiotensin and dopamine has been demonstrated. Regulatory interactions between the dopaminergic and renin-angiotensin systems have recently been described in the substantia nigra and striatum. In animal models, dopamine depletion induces compensatory overactivation of the local renin-angiotensin system, which primes microglial responses and neuron vulnerability by activating NADPH-oxidase. Hyperactivation of the local renin-angiotensin system exacerbates the inflammatory microglial response, oxidative stress, and dopaminergic degeneration, all of which are inhibited by angiotensin receptor blockers and inhibitors of angiotensin-converting enzymes. In this review we provide evidence suggesting that the renin-angiotensin system may play an important role in dopamine's mediated neuroinflammation and oxidative stress changes in Parkinson's disease. We suggest that manipulating brain angiotensin may constitute an effective neuroprotective strategy for Parkinson's disease.
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Affiliation(s)
- Jose L Labandeira-Garcia
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Faculty of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
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Michel MC, Foster C, Brunner HR, Liu L. A systematic comparison of the properties of clinically used angiotensin II type 1 receptor antagonists. Pharmacol Rev 2013; 65:809-48. [PMID: 23487168 DOI: 10.1124/pr.112.007278] [Citation(s) in RCA: 219] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Angiotensin II type 1 receptor antagonists (ARBs) have become an important drug class in the treatment of hypertension and heart failure and the protection from diabetic nephropathy. Eight ARBs are clinically available [azilsartan, candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan, valsartan]. Azilsartan (in some countries), candesartan, and olmesartan are orally administered as prodrugs, whereas the blocking action of some is mediated through active metabolites. On the basis of their chemical structures, ARBs use different binding pockets in the receptor, which are associated with differences in dissociation times and, in most cases, apparently insurmountable antagonism. The physicochemical differences between ARBs also manifest in different tissue penetration, including passage through the blood-brain barrier. Differences in binding mode and tissue penetration are also associated with differences in pharmacokinetic profile, particularly duration of action. Although generally highly specific for angiotensin II type 1 receptors, some ARBs, particularly telmisartan, are partial agonists at peroxisome proliferator-activated receptor-γ. All of these properties are comprehensively reviewed in this article. Although there is general consensus that a continuous receptor blockade over a 24-hour period is desirable, the clinical relevance of other pharmacological differences between individual ARBs remains to be assessed.
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Affiliation(s)
- Martin C Michel
- Department of Clinical Development & Medical Affairs, Boehringer Ingelheim, 55216 Ingelheim, Germany.
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Toba H, Wang J, Ohigashi M, Kobara M, Nakata T. Telmisartan Protects against Vascular Dysfunction with Peroxisome Proliferator-Activated Receptor-γ Activation in Hypertensive 5/6 Nephrectomized Rats. Pharmacology 2013; 92:265-75. [DOI: 10.1159/000355482] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/06/2013] [Indexed: 11/19/2022]
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The Angiotensin II Type 2 Receptor in Brain Functions: An Update. Int J Hypertens 2012; 2012:351758. [PMID: 23320146 PMCID: PMC3540774 DOI: 10.1155/2012/351758] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 11/29/2012] [Indexed: 02/07/2023] Open
Abstract
Angiotensin II (Ang II) is the main active product of the renin-angiotensin system (RAS), mediating its action via two major receptors, namely, the Ang II type 1 (AT1) receptor and the type 2 (AT2) receptor. Recent results also implicate several other members of the renin-angiotensin system in various aspects of brain functions. The first aim of this paper is to summarize the current state of knowledge regarding the properties and signaling of the AT2 receptor, its expression in the brain, and its well-established effects. Secondly, we will highlight the potential role of the AT2 receptor in cognitive function, neurological disorders and in the regulation of appetite and the possible link with development of metabolic disorders. The potential utility of novel nonpeptide selective AT2 receptor ligands in clarifying potential roles of this receptor in physiology will also be discussed. If confirmed, these new pharmacological tools should help to improve impaired cognitive performance, not only through its action on brain microcirculation and inflammation, but also through more specific effects on neurons. However, the overall physiological relevance of the AT2 receptor in the brain must also consider the Ang IV/AT4 receptor.
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Abstract
The effects of brain AngII (angiotensin II) depend on AT(1) receptor (AngII type 1 receptor) stimulation and include regulation of cerebrovascular flow, autonomic and hormonal systems, stress, innate immune response and behaviour. Excessive brain AT(1) receptor activity associates with hypertension and heart failure, brain ischaemia, abnormal stress responses, blood-brain barrier breakdown and inflammation. These are risk factors leading to neuronal injury, the incidence and progression of neurodegerative, mood and traumatic brain disorders, and cognitive decline. In rodents, ARBs (AT(1) receptor blockers) ameliorate stress-induced disorders, anxiety and depression, protect cerebral blood flow during stroke, decrease brain inflammation and amyloid-β neurotoxicity and reduce traumatic brain injury. Direct anti-inflammatory protective effects, demonstrated in cultured microglia, cerebrovascular endothelial cells, neurons and human circulating monocytes, may result not only in AT(1) receptor blockade, but also from PPARγ (peroxisome-proliferator-activated receptor γ) stimulation. Controlled clinical studies indicate that ARBs protect cognition after stroke and during aging, and cohort analyses reveal that these compounds significantly reduce the incidence and progression of Alzheimer's disease. ARBs are commonly used for the therapy of hypertension, diabetes and stroke, but have not been studied in the context of neurodegenerative, mood or traumatic brain disorders, conditions lacking effective therapy. These compounds are well-tolerated pleiotropic neuroprotective agents with additional beneficial cardiovascular and metabolic profiles, and their use in central nervous system disorders offers a novel therapeutic approach of immediate translational value. ARBs should be tested for the prevention and therapy of neurodegenerative disorders, in particular Alzheimer's disease, affective disorders, such as co-morbid cardiovascular disease and depression, and traumatic brain injury.
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Affiliation(s)
- Juan M Saavedra
- Section on Pharmacology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892, USA.
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Ergul A, Kelly-Cobbs A, Abdalla M, Fagan SC. Cerebrovascular complications of diabetes: focus on stroke. Endocr Metab Immune Disord Drug Targets 2012; 12:148-58. [PMID: 22236022 DOI: 10.2174/187153012800493477] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 09/27/2011] [Indexed: 12/18/2022]
Abstract
Cerebrovascular complications make diabetic patients 2-6 times more susceptible to a stroke event and this risk is magnified in younger individuals and in patients with hypertension and complications in other vascular beds. In addition, when patients with diabetes and hyperglycemia experience an acute ischemic stroke they are more likely to die or be severely disabled and less likely to benefit from the one FDA-approved therapy, intravenous tissue plasminogen activator. Experimental stroke models have revealed that chronic hyperglycemia leads to deficits in cerebrovascular structure and function that may explain some of the clinical observations. Increased edema, neovascularization and protease expression as well as altered vascular reactivity and tone may be involved and point to potential therapeutic targets. Further study is needed to fully understand this complex disease state and the breadth of its manifestation in the cerebrovasculature.
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Affiliation(s)
- Adviye Ergul
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA 30912, USA
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Differential effects of short-term treatment with two AT1 receptor blockers on diameter of pial arterioles in SHR. PLoS One 2012; 7:e42469. [PMID: 22957022 PMCID: PMC3434186 DOI: 10.1371/journal.pone.0042469] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/09/2012] [Indexed: 11/19/2022] Open
Abstract
Chronic treatment with angiotensin receptor blockers is largely accepted for protecting cerebral circulation during hypertension, but beneficial effects of short-term treatments are questionable, as highlighted by the recent SCAST trial. We compared the impact of 10 days treatment with candesartan (as SCAST) versus telmisartan (previously described to reverse arteriolar remodeling, chronic treatment) on pial arterioles of spontaneously hypertensive rats (SHR). We explored whether PPAR-gamma agonist activity or AT(1) receptor blockade are involved in their differential effects. In the first study, 4-month-old male SHR were treated with telmisartan (TELMI, 2 mg/kg per day) or candesartan cilexetil (CANDE, 10 mg/kg per day) and compared to vehicle treated SHR and normotensive WKY. In a second study, SHR were treated with CANDE, pioglitazone (a PPAR-gamma agonist, PIO 2.5 mg/kg per day) or CANDE+PIO, compared to TELMI. Internal diameter of pial arterioles (ID, cranial window) was measured at baseline, during hemorrhage-induced hypotension, or following suffusion of Ang II (10(-6) mol/L) or EDTA inactivation of smooth muscle cells (passive ID). PPAR-gamma and eNOS (target gene of PPAR-gamma) mRNA were evaluated in brain microvessels. For similar antihypertensive effects, TELMI (+44% versus SHR), but not CANDE, increased baseline ID. During hemorrhage, ID in TELMI group was similar to WKY, while ID in SHR and CANDE remained lower. In the second study, TELMI (+36%, versus SHR) and CANDE+PIO (+43%) increased baseline ID, but not CANDE or PIO alone. TELMI (-66%) and CANDE+PIO (-69%), but neither CANDE nor PIO alone, decreased Ang II-induced vasoconstriction. CANDE+PIO, but not CANDE, increased passive ID. In both studies, PPAR-gamma and eNOS expressions were higher in TELMI than CANDE. Short-term treatment with TELMI, but not with CANDE, reverses narrowing of pial arteriolar ID in SHR. This may involve PPAR-gamma related mechanisms, since CANDE+PIO treatment induced similar effects, and a better blockade of AT(1) receptors.
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Kishi T, Hirooka Y, Sunagawa K. Telmisartan protects against cognitive decline via up-regulation of brain-derived neurotrophic factor/tropomyosin-related kinase B in hippocampus of hypertensive rats. J Cardiol 2012; 60:489-94. [PMID: 22948091 DOI: 10.1016/j.jjcc.2012.08.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 05/24/2012] [Accepted: 06/20/2012] [Indexed: 12/23/2022]
Abstract
BACKGROUND AND PURPOSE Cognitive decline may occur as a result of hypertension, and is dependent on the function of hippocampus. Brain-derived neurotrophic factor (BDNF) mediated by angiotensin II-induced oxidative stress protects against cell death in hippocampus. Angiotensin II receptor blocker (ARB), candesartan, activates BDNF in the hippocampus. Furthermore, peroxisome proliferator-activated receptor (PPAR)-gamma activation in the brain prevents brain damage. Telmisartan, a unique ARB with PPAR-gamma stimulating activity, protects against cognitive decline partly because of PPAR-gamma activation. The aim of the present study was to determine whether telmisartan protects against cognitive decline via up-regulation of BDNF and its receptor tropomyosin-related kinase B (TrkB) in the hippocampus of hypertensive rats, partly because of PPAR-gamma activation. METHODS AND RESULTS We divided stroke-prone spontaneously hypertensive rats (SHRSPs), as hypertensive and vascular dementia model rats, into five groups, telmisartan-treated (TLM), TLM+GW9662, a PPAR-gamma inhibitor, -treated (T+G), GW9662-treated (GW), TLM+ANA-12, a TrkB antagonist, -treated (T+A), and vehicle-treated SHRSPs (VEH). After the treatment for 28 days, systolic blood pressure did not change in all groups. However, BDNF expression in the hippocampus was significantly higher in TLM than in VEH to a greater extent than in T+G. Cognitive performance was significantly higher in TLM than in VEH to a greater extent than in T+G, and was not different between T+A, GW, and VEH. CONCLUSION Telmisartan protects against cognitive decline via up-regulation of BDNF/TrkB in the hippocampus of SHRSPs, partly because of PPAR-gamma activation independent of blood pressure-lowering effect.
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Affiliation(s)
- Takuya Kishi
- Department of Advanced Therapeutics for Cardiovascular Diseases, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
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Effects of telmisartan on the cerebral circulation of hypertensive patients with chronic-stage stroke. Hypertens Res 2012; 35:1171-5. [PMID: 22763480 DOI: 10.1038/hr.2012.105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This prospective study examined the effects of telmisartan, an angiotensin II type I receptor blocker with peroxisome proliferator-activated receptor gamma agonistic action, on blood pressure (BP) control and cerebral circulation in hypertensive patients with chronic-stage stroke. Telmisartan (40 mg per day) was administered to 10 patients with systolic BP (SBP) 140 mm Hg and diastolic BP (DBP) 90 mm Hg at least 4 weeks after lacunar or atherothrombotic infarction. Casual BP and resting cerebral blood flow (CBF) were evaluated at baseline and week 12 using technetium-99 m ethyl cysteinate dimer single-photon emission computed tomography. Both SBP and DBP declined significantly from 156.4±17.0 to 127.4±6.6 mm Hg and 84.2±14.5 to 74.2±5.2 mm Hg, respectively (P<0.05). Mean CBF (mCBF) in both the left and right cerebral hemispheres did not change, and the mCBF of both the impaired and unimpaired sides of supratentorial lesion patients (n=6) did not change. Investigation of regional CBF in all patients revealed significant increases in the callosomarginal, precentral, central, parietal, temporal, posterior cerebral, lenticular nucleus, thalamic and hippocampal regions at week 12 (P<0.05). Telmisartan showed good antihypertensive activity in hypertensive patients with chronic-stage stroke without affecting hemispheric blood flow, and it even increased regional CBF in most regions examined.
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Clinical neuroprotective drugs for treatment and prevention of stroke. Int J Mol Sci 2012; 13:7739-7761. [PMID: 22837724 PMCID: PMC3397556 DOI: 10.3390/ijms13067739] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/15/2012] [Accepted: 06/19/2012] [Indexed: 01/12/2023] Open
Abstract
Stroke is an enormous public health problem with an imperative need for more effective therapies. In therapies for ischemic stroke, tissue plasminogen activators, antiplatelet agents and anticoagulants are used mainly for their antithrombotic effects. However, free radical scavengers, minocycline and growth factors have shown neuroprotective effects in the treatment of stroke, while antihypertensive drugs, lipid-lowering drugs and hypoglycemic drugs have shown beneficial effects for the prevention of stroke. In the present review, we evaluate the treatment and prevention of stroke in light of clinical studies and discuss new anti-stroke effects other than the main effects of drugs, focusing on optimal pharmacotherapy.
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Telmisartan inhibits vascular dysfunction and inflammation via activation of peroxisome proliferator-activated receptor-γ in subtotal nephrectomized rat. Eur J Pharmacol 2012; 685:91-8. [DOI: 10.1016/j.ejphar.2012.01.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 01/13/2012] [Accepted: 01/18/2012] [Indexed: 11/23/2022]
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Pang T, Wang J, Benicky J, Sánchez-Lemus E, Saavedra JM. Telmisartan directly ameliorates the neuronal inflammatory response to IL-1β partly through the JNK/c-Jun and NADPH oxidase pathways. J Neuroinflammation 2012; 9:102. [PMID: 22642771 PMCID: PMC3410820 DOI: 10.1186/1742-2094-9-102] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 05/29/2012] [Indexed: 12/18/2022] Open
Abstract
Background Blockade of angiotensin II type 1 (AT1) receptors ameliorates brain inflammation, and reduces excessive brain interleukin-1 beta (IL-1β) production and release from cortical microglia. The aim of this study was to determine whether, in addition, AT1 receptor blockade directly attenuates IL-1β-induced inflammatory responses in neuronal cultures. Methods SK-N-SH human neuroblasts and primary rat cortical neurons were pretreated with telmisartan followed by exposure to IL-1β. Gene expression was determined by reverse transcriptase (RT)-PCR, protein expression and kinase activation by western blotting, NADPH oxidase activity by the lucigenin method, prostaglandin E2 (PGE2) release by enzyme immunoassay, reactive oxygen species (ROS) generation by the dichlorodihydrofluorescein diacetate fluorescent probe assay, and peroxisome proliferator-activated receptor gamma (PPARγ) involvement was assessed with the antagonists GW9662 and T0070907, the agonist pioglitazone and the expression of PPARγ target genes ABCG1 and CD36. Results We found that SK-N-SH neuroblasts expressed AT1 but not AT2 receptor mRNA. Telmisartan reduced IL-1β-induced cyclooxygenase-2 (COX-2) expression and PGE2 release more potently than did candesartan and losartan. Telmisartan reduced the IL-1β-induced increase in IL-1R1 receptor and NADPH oxidase-4 (NOX-4) mRNA expression, NADPH oxidase activity, and ROS generation, and reduced hydrogen peroxide-induced COX-2 gene expression. Telmisartan did not modify IL-1β-induced ERK1/2 and p38 mitogen-activated protein kinase (MAPK) phosphorylation or nuclear factor-κB activation but significantly decreased IL-1β-induced c-Jun N-terminal kinase (JNK) and c-Jun activation. The JNK inhibitor SP600125 decreased IL-1β-induced PGE2 release with a potency similar to that of telmisartan. The PPARγ agonist pioglitazone reduced IL-1β-induced inflammatory reaction, whereas telmisartan did not activate PPARγ, as shown by its failure to enhance the expression of the PPARγ target genes ABCG1 and CD36, and the inability of the PPARγ antagonists GW9662 and T0070907 to modify the effect of telmisartan on COX-2 induction. The effect of telmisartan on IL-1β-stimulated COX-2 and IL-1R1 mRNA expression and ROS production was replicated in primary rat cortical neurons. Conclusions Telmisartan directly ameliorates IL-1β-induced neuronal inflammatory response by inhibition of oxidative stress and the JNK/c-Jun pathway. Our results support the hypothesis that AT1 receptor blockers are directly neuroprotective, and should be considered for the treatment of inflammatory conditions of the brain.
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Affiliation(s)
- Tao Pang
- Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Section on Pharmacology, NIMH, NIH, DHHS, 10 Center Drive, Bldg, 10, Room # 2D-57, Bethesda, MD, 20892, USA.
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Abstract
The RAS (renin–angiotensin system) plays a role not only in the cardiovascular system, including blood pressure regulation, but also in the central nervous system. AngII (angiotensin II) binds two major receptors: the AT1 receptor (AngII type 1 receptor) and AT2 receptor (AngII type 2 receptor). It has been recognized that AT2 receptor activation not only opposes AT1 receptor actions, but also has unique effects beyond inhibitory cross-talk with AT1 receptor signalling. Novel pathways beyond the classical actions of RAS, the ACE (angiotensin-converting enzyme)/AngII/AT1 receptor axis, have been highlighted: the ACE2/Ang-(1–7) [angiotensin-(1–7)]/Mas receptor axis as a new opposing axis against the ACE/AngII/AT1 receptor axis, novel AngII-receptor-interacting proteins and various AngII-receptor-activation mechanisms including dimer formation. ATRAP (AT1-receptor-associated protein) and ATIP (AT2-receptor-interacting protein) are well-characterized AngII-receptor-associated proteins. These proteins could regulate the functions of AngII receptors and thereby influence various pathophysiological states. Moreover, the possible cross-talk between PPAR (peroxisome-proliferator-activated receptor)-γ and AngII receptor subtypes is an intriguing issue to be addressed in order to understand the roles of RAS in the metabolic syndrome, and interestingly some ARBs (AT1-receptor blockers) have been reported to have an AT1-receptor-blocking action with a partial PPAR-γ agonistic effect. These emerging concepts concerning the regulation of AngII receptors are discussed in the present review.
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Garrido-Gil P, Joglar B, Rodriguez-Perez AI, Guerra MJ, Labandeira-Garcia JL. Involvement of PPAR-γ in the neuroprotective and anti-inflammatory effects of angiotensin type 1 receptor inhibition: effects of the receptor antagonist telmisartan and receptor deletion in a mouse MPTP model of Parkinson's disease. J Neuroinflammation 2012; 9:38. [PMID: 22356806 PMCID: PMC3298706 DOI: 10.1186/1742-2094-9-38] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 02/22/2012] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Several recent studies have shown that angiotensin type 1 receptor (AT1) antagonists such as candesartan inhibit the microglial inflammatory response and dopaminergic cell loss in animal models of Parkinson's disease. However, the mechanisms involved in the neuroprotective and anti-inflammatory effects of AT1 blockers in the brain have not been clarified. A number of studies have reported that AT1 blockers activate peroxisome proliferator-activated receptor gamma (PPAR γ). PPAR-γ activation inhibits inflammation, and may be responsible for neuroprotective effects, independently of AT1 blocking actions. METHODS We have investigated whether oral treatment with telmisartan (the most potent PPAR-γ activator among AT1 blockers) provides neuroprotection against dopaminergic cell death and neuroinflammation, and the possible role of PPAR-γ activation in any such neuroprotection. We used a mouse model of parkinsonism induced by the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and co-administration of the PPAR-γ antagonist GW9662 to study the role of PPAR-γ activation. In addition, we used AT1a-null mice lesioned with MPTP to study whether deletion of AT1 in the absence of any pharmacological effect of AT1 blockers provides neuroprotection, and investigated whether PPAR-γ activation may also be involved in any such effect of AT1 deletion by co-administration of the PPAR-γ antagonist GW9662. RESULTS We observed that telmisartan protects mouse dopaminergic neurons and inhibits the microglial response induced by administration of MPTP. The protective effects of telmisartan on dopaminergic cell death and microglial activation were inhibited by co-administration of GW9662. Dopaminergic cell death and microglial activation were significantly lower in AT1a-null mice treated with MPTP than in mice not subjected to AT1a deletion. Interestingly, the protective effects of AT1 deletion were also inhibited by co-administration of GW9662. CONCLUSION The results suggest that telmisartan provides effective neuroprotection against dopaminergic cell death and that the neuroprotective effect is mediated by PPAR-γ activation. However, the results in AT1-deficient mice show that blockage of AT1, unrelated to the pharmacological properties of AT1 blockers, also protects against dopaminergic cell death and neuroinflammation. Furthermore, the results show that PPAR-γ activation is involved in the anti-inflammatory and neuroprotective effects of AT1 deletion.
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Affiliation(s)
- Pablo Garrido-Gil
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Faculty of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain
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Guimond MO, Gallo-Payet N. How does angiotensin AT(2) receptor activation help neuronal differentiation and improve neuronal pathological situations? Front Endocrinol (Lausanne) 2012; 3:164. [PMID: 23267346 PMCID: PMC3525946 DOI: 10.3389/fendo.2012.00164] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 11/29/2012] [Indexed: 01/08/2023] Open
Abstract
The angiotensin type 2 (AT(2)) receptor of angiotensin II has long been thought to be limited to few tissues, with the primary effect of counteracting the angiotensin type 1 (AT(1)) receptor. Functional studies in neuronal cells have demonstrated AT(2) receptor capability to modulate neuronal excitability, neurite elongation, and neuronal migration, suggesting that it may be an important regulator of brain functions. The observation that the AT(2) receptor was expressed in brain areas implicated in learning and memory led to the hypothesis that it may also be implicated in cognitive functions. However, linking signaling pathways to physiological effects has always proven challenging since information relative to its physiological functions has mainly emerged from indirect observations, either from the blockade of the AT(1) receptor or through the use of transgenic animals. From a mechanistic standpoint, the main intracellular pathways linked to AT(2) receptor stimulation include modulation of phosphorylation by activation of kinases and phosphatases or the production of nitric oxide and cGMP, some of which are associated with the Gi-coupling protein. The receptor can also interact with other receptors, either G protein-coupled such as bradykinin, or growth factor receptors such as nerve growth factor or platelet-derived growth factor receptors. More recently, new advances have also led to identification of various partner proteins, thus providing new insights into this receptor's mechanism of action. This review summarizes the recent advances regarding the signaling pathways induced by the AT(2) receptor in neuronal cells, and discussed the potential therapeutic relevance of central actions of this enigmatic receptor. In particular, we highlight the possibility that selective AT(2) receptor activation by non-peptide and selective agonists could represent new pharmacological tools that may help to improve impaired cognitive performance in Alzheimer's disease and other neurological cognitive disorders.
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Affiliation(s)
| | - Nicole Gallo-Payet
- *Correspondence: Nicole Gallo-Payet, Service d’Endocrinologie, Département de Médecine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4. e-mail:
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Horiuchi M, Mogi M. Role of angiotensin II receptor subtype activation in cognitive function and ischaemic brain damage. Br J Pharmacol 2011; 163:1122-30. [PMID: 21175580 DOI: 10.1111/j.1476-5381.2010.01167.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Recent clinical studies have demonstrated that angiotensin II type 1 (AT(1) ) receptor blockers (ARBs) reduce the onset of stroke, stroke severity and the incidence and progression of Alzheimer's disease and dementia. We can expect that ARBs exert these effects by both AT(1) receptor blockade and angiotensin II type 2 (AT(2) ) receptor stimulation. Moreover, recent experimental results support the notion that AT(2) receptor stimulation with AT(1) receptor blockade could contribute to protection against ischaemic brain damage at least partly due to an increase in cerebral blood flow and decrease in oxidative stress, and prevent cognitive decline. Cellular therapy has been focused on as a new therapeutic approach to restore injured neurons. In this context, it has been reported that AT(2) receptor stimulation enhances neurite outgrowth and decreases neural damage, thereby enhancing neurogenesis. Moreover, additional beneficial effects of ARBs with an AT(1) receptor blocking action with a partial peroxisome proliferator-activated receptor (PPAR)-γ agonistic effect have been reported, and interaction of AT(2) receptor activation and PPAR-γ might be involved in these ARBs' effects. This article reviews the effects of regulation of activation of angiotensin II receptor subtypes on ischaemic brain damage and cognitive function, focusing on the effects of AT(2) receptor stimulation.
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Affiliation(s)
- Masatsugu Horiuchi
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Tohon, Ehime, Japan.
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Jaggi AS, Singh N. Exploring the potential of telmisartan in chronic constriction injury-induced neuropathic pain in rats. Eur J Pharmacol 2011; 667:215-21. [DOI: 10.1016/j.ejphar.2011.06.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 04/05/2011] [Accepted: 06/14/2011] [Indexed: 12/16/2022]
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Xu X, Yin X, Feng W, Li G, Wang D, Tu L. Telmisartan protects against insulin resistance by attenuating inflammatory response in rats. ACTA ACUST UNITED AC 2011; 31:317-323. [DOI: 10.1007/s11596-011-0374-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Indexed: 12/29/2022]
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Irbesartan attenuates ischemic brain damage by inhibition of MCP-1/CCR2 signaling pathway beyond AT1 receptor blockade. Biochem Biophys Res Commun 2011; 409:275-9. [DOI: 10.1016/j.bbrc.2011.04.142] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 04/29/2011] [Indexed: 11/21/2022]
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Angiotensin II and aldosterone-induced neuronal damage in neurons through an astrocyte-dependent mechanism. Hypertens Res 2011; 34:773-8. [PMID: 21471976 DOI: 10.1038/hr.2011.38] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The contribution of the renin-angiotensin-aldosterone system (RAAS) to central nervous system (CNS) disorders is not yet fully understood. RAAS has been shown to be involved in the proliferation of astrocytes, which have a role in neuronal damage contributing to neurodegenerative diseases. However, the direct relationship between RAAS and neuronal damage is still unclear. We therefore examined the effect of angiotensin (Ang) II and aldosterone (Aldo) on damage to spinal ganglion neurons (SGNs) by regulating astrocytes. Ang II stimulation significantly increased DNA damage in SGNs in a time-dependent manner. This increase in DNA damage was further enhanced when SGNs were co-cultured with astrocytes. On the other hand, no significant increase was observed in SGNs co-cultured with astrocytes without Ang II stimulation. Moreover, the addition of conditioned medium from Ang II-treated astrocytes exacerbated SGN DNA damage. An Ang II type 1 receptor blocker, valsartan, inhibited Ang II-stimulated DNA damage but not DNA damage induced by conditioned medium prepared from astrocyte cultures. In contrast, an Aldo antagonist, eplerenone, significantly inhibited DNA damage induced by the culture medium from Ang II-treated astrocytes. Ang II-stimulated Aldo secretion in the conditioned medium from astrocytes. Furthermore, the administration of Aldo alone also enhanced DNA damage in SGNs. Finally, flow cytometric analysis showed that Ang II or Aldo treatment markedly increased the percentage of dead SGNs. In conclusion, Ang II- and Aldo-induced neuronal damage in SGNs through astrocytes regulation. Blocking Ang II and Aldo to target astrocytes might be useful for the treatment of CNS disorders.
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