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Chen X, Yan X, Gingerich L, Chen QH, Bi L, Shan Z. Induction of Neuroinflammation and Brain Oxidative Stress by Brain-Derived Extracellular Vesicles from Hypertensive Rats. Antioxidants (Basel) 2024; 13:328. [PMID: 38539860 PMCID: PMC10967780 DOI: 10.3390/antiox13030328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 02/16/2024] [Accepted: 03/03/2024] [Indexed: 06/20/2024] Open
Abstract
Neuroinflammation and brain oxidative stress are recognized as significant contributors to hypertension including salt sensitive hypertension. Extracellular vesicles (EVs) play an essential role in intercellular communication in various situations, including physiological and pathological ones. Based on this evidence, we hypothesized that EVs derived from the brains of hypertensive rats with salt sensitivity could trigger neuroinflammation and oxidative stress during hypertension development. To test this hypothesis, we compared the impact of EVs isolated from the brains of hypertensive Dahl Salt-Sensitive rats (DSS) and normotensive Sprague Dawley (SD) rats on inflammatory factors and mitochondrial reactive oxygen species (mtROS) production in primary neuronal cultures and brain cardiovascular relevant regions, including the hypothalamic paraventricular nucleus (PVN) and lamina terminalis (LT). We found that brain-derived DSS-EVs significantly increased the mRNA levels of proinflammatory cytokines (PICs) and chemokines, including TNFα, IL1β, CCL2, CCL5, and CCL12, as well as the transcriptional factor NF-κB in neuronal cultures. DSS-EVs also induced oxidative stress in neuronal cultures, as evidenced by elevated NADPH oxidase subunit CYBA coding gene mRNA levels and persistent mtROS elevation. When DSS-EVs were injected into the brains of normal SD rats, the mRNA levels of PICs, chemokines, and the chronic neuronal activity marker FOSL1 were significantly increased in the PVN and LT. Furthermore, DSS-EVs caused mtROS elevation in brain PVN and LT, particularly in neurons. Our study reveals a novel role for brain-derived EVs from hypertensive rats in triggering neuroinflammation, upregulating chemokine expression, and inducing excessive ROS production. These findings provide insight into the complex interactions between EVs and hypertension-associated processes, offering potential therapeutic targets for hypertension-linked neurological complications.
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Affiliation(s)
- Xinqian Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI 49931, USA
- Health Research Institute, Michigan Technological University, Houghton, MI 49931, USA
| | - Xin Yan
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA
| | - Leah Gingerich
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI 49931, USA
| | - Qing-Hui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI 49931, USA
- Health Research Institute, Michigan Technological University, Houghton, MI 49931, USA
| | - Lanrong Bi
- Health Research Institute, Michigan Technological University, Houghton, MI 49931, USA
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI 49931, USA
- Health Research Institute, Michigan Technological University, Houghton, MI 49931, USA
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Villa RF, Ferrari F, Gorini A. Effects of Chronic Hypertension on the Energy Metabolism of Cerebral Cortex Mitochondria in Normotensive and in Spontaneously Hypertensive Rats During Aging. Neuromolecular Med 2024; 26:2. [PMID: 38393429 DOI: 10.1007/s12017-023-08772-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 12/02/2023] [Indexed: 02/25/2024]
Abstract
In this study the subcellular modifications undergone by cerebral cortex mitochondrial metabolism in chronic hypertension during aging were evaluated. The catalytic properties of regulatory energy-linked enzymes of Tricarboxylic Acid Cycle (TCA), Electron Transport Chain (ETC) and glutamate metabolism were assayed on non-synaptic mitochondria (FM, located in post-synaptic compartment) and on intra-synaptic mitochondria of pre-synaptic compartment, furtherly divided in "light" (LM) and "heavy" (HM) mitochondria, purified form cerebral cortex of normotensive Wistar Kyoto Rats (WKY) versus Spontaneously Hypertensive Rats (SHR) at 6, 12 and 18 months. During physiological aging, the metabolic machinery was differently expressed in pre- and post-synaptic compartments: LM and above all HM were more affected by aging, displaying lower ETC activities. In SHR at 6 months, FM and LM showed an uncoupling between TCA and ETC, likely as initial adaptive response to hypertension. During pathological aging, HM were particularly affected at 12 months in SHR, as if the adaptive modifications in FM and LM at 6 months granted a mitochondrial functional balance, while at 18 months all the neuronal mitochondria displayed decreased metabolic fluxes versus WKY. This study describes the effects of chronic hypertension on cerebral mitochondrial energy metabolism during aging through functional proteomics of enzymes at subcellular levels, i.e. in neuronal soma and synapses. In addition, this represents the starting point to envisage an experimental physiopathological model which could be useful also for pharmacological studies, to assess drug actions during the development of age-related pathologies that could coexist and/or are provoked by chronic hypertension.
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Affiliation(s)
- Roberto Federico Villa
- Department of Biology and Biotechnology, Laboratory of Pharmacology and Molecular Medicine of Central Nervous System, University of Pavia, Via Ferrata, 9, 27100, Pavia, Italy.
| | - Federica Ferrari
- Department of Biology and Biotechnology, Laboratory of Pharmacology and Molecular Medicine of Central Nervous System, University of Pavia, Via Ferrata, 9, 27100, Pavia, Italy
- School of Neurology, Department of Brain and Behavioral Sciences, University of Pavia, Via Bassi. 21, 27100, Pavia, Italy
| | - Antonella Gorini
- Department of Biology and Biotechnology, Laboratory of Pharmacology and Molecular Medicine of Central Nervous System, University of Pavia, Via Ferrata, 9, 27100, Pavia, Italy
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Nagata K, Tagami K, Okuzawa T, Hayakawa M, Nomura A, Nishimura T, Ikeda K, Kitada K, Kobuchi S, Fujisawa Y, Nishiyama A, Murohara T. Comparison of the effects of renal denervation at early or advanced stages of hypertension on cardiac, renal, and adipose tissue pathology in Dahl salt-sensitive rats. Hypertens Res 2024:10.1038/s41440-024-01605-x. [PMID: 38355818 DOI: 10.1038/s41440-024-01605-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 12/05/2023] [Accepted: 01/17/2024] [Indexed: 02/16/2024]
Abstract
Renal denervation (RDN) has emerged as a novel therapy for drug-resistant hypertension. We here examined the effects of RDN at early versus advanced stages of hypertension on blood pressure and organ pathology in rats with salt-sensitive hypertension. Dahl salt-sensitive (DahlS) rats fed an 8% NaCl diet from 6 weeks of age were subjected to RDN (surgical ablation and application of 10% phenol in ethanol) or sham surgery at 7 (early stage) or 9 (advanced stage) weeks and were studied at 12 weeks. RDN at early or advanced stages resulted in a moderate lowering of blood pressure. Although RDN at neither stage affected left ventricular (LV) and cardiomyocyte hypertrophy, it ameliorated LV diastolic dysfunction, fibrosis, and inflammation at both stages. Intervention at both stages also attenuated renal injury as well as downregulated the expression of angiotensinogen and angiotensin-converting enzyme (ACE) genes and angiotensin II type 1 receptor protein in the kidney. Furthermore, RDN at both stages inhibited proinflammatory gene expression in adipose tissue. The early intervention reduced both visceral fat mass and adipocyte size in association with downregulation of angiotensinogen and ACE gene expression. In contrast, the late intervention increased fat mass without affecting adipocyte size as well as attenuated angiotensinogen and ACE gene expression. Our results thus indicate that RDN at early or late stages after salt loading moderately alleviated hypertension and substantially ameliorated cardiac and renal injury and adipose tissue inflammation in DahlS rats. They also suggest that cross talk among the kidney, cardiovascular system, and adipose tissue may contribute to salt-sensitive hypertension. Supposed mechanism for the beneficial effects of RDN on hypertension and target organ damage in DahlS rats. RDN at early or late stages after salt loading moderately alleviated hypertension and substantially ameliorated renal injury in DahlS rats. Cross talk among the kidney, cardiovascular system, and adipose tissue possibly mediated by circulating RAS may contribute to salt-sensitive hypertension. LV; left ventricular, NE; norepinephrine, RAS; renin-angiotensin system, RDN; renal denervation.
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Affiliation(s)
- Kohzo Nagata
- Pathophysiology Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Kaito Tagami
- Pathophysiology Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Touko Okuzawa
- Pathophysiology Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Misaki Hayakawa
- Pathophysiology Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akane Nomura
- Department of Medical Technology, Nagoya University School of Health Sciences, Nagoya, Japan
| | - Tomo Nishimura
- Department of Medical Technology, Nagoya University School of Health Sciences, Nagoya, Japan
| | - Katsuhide Ikeda
- Pathophysiology Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kento Kitada
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Shuhei Kobuchi
- Division of Pharmacology, School of Pharmacy, Department of Pharmacy, Hyogo Medical University, Kobe, Japan
| | - Yoshihide Fujisawa
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Toyoaki Murohara
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Yang P, Wang Y, Ge W, Jing Y, Hu H, Yin J, Xue M, Wang Y, Li X, Li X, Shi Y, Tan J, Li Y, Yan S. m6A methyltransferase METTL3 contributes to sympathetic hyperactivity post-MI via promoting TRAF6-dependent mitochondrial ROS production. Free Radic Biol Med 2023; 209:342-354. [PMID: 37898386 DOI: 10.1016/j.freeradbiomed.2023.10.392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/17/2023] [Accepted: 10/13/2023] [Indexed: 10/30/2023]
Abstract
OBJECTIVES N6-methyladenosine (m6A) is the most prevalent post-translational modification in eukaryotic mRNA. Recently, m6A editing modified by methyltransferase-like enzyme 3 (METTL3), the core m6A methyltransferase, has been demonstrated to be involved in cardiac sympathetic hyperactivity. This study aimed to clarify the effects and underlying mechanisms of METTL3 in the paraventricular nucleus (PVN) in mediating sympathetic activity following myocardial infarction (MI). METHODS We established rat MI models by left anterior descending coronary artery ligation. m6A quantification was performed.The expression of METTL3 and its downstream gene, tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6), were determined. The functional role of METTL3 in sympathetic hyperactivity and electrical conduction stability were verified by assessing renal sympathetic nerve activity (RSNA), norepinephrine (NE) levels, and programmed electrical stimulation. Rescue experiments were also conducted. The mechanism by which m6A is involved in mitochondrial reactive oxygen species (mROS) production, mediated by TRAF6/ECSIT pathway, was explored in lipopolysaccharide (LPS) treated primary microglial cells. RESULTS METTL3 was predominantly localized in the microglia and significantly increased within the PVN at 3 days post-MI. Inhibition of METTL3 decreased m6A levels, TRAF6 expression, and mROS production; downregulated sympathoexcitation, indicated by attenuated NE concentration and RSNA; decreased the incidence of ventricular tachycardia or fibrillation; and improved cardiac function. Mechanistically, downregulation of METTL3 prevented TRAF6 translocation to the mitochondria in the microglia and subsequent TRAF6/ECSIT pathway activation, resulting in decreased mROS production. CONCLUSIONS This study demonstrates that METTL3-mediated m6A modification promotes sympathetic hyperactivity through TRAF6/ECSIT pathway and mitochondrial oxidative stress in the PVN, thereby leading to ventricular arrhythmias post-MI.
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Affiliation(s)
- Peijin Yang
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China; Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Yu Wang
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Weili Ge
- Department of Cardiology, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Zhejiang, China
| | - Yanyan Jing
- Department of Cardiology, Yantai Yuhuangding Hospital, Yantai, China
| | - Hesheng Hu
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Jie Yin
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Mei Xue
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Ye Wang
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Xiaolu Li
- Department of Emergency, The First Affiliated Hospital of Shandong First Medical University, Jinan, China
| | - Xinran Li
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Yugen Shi
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Jiayu Tan
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Yan Li
- Medical Research Center, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China
| | - Suhua Yan
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Cardiac Electrophysiology and Arrhythmia, Jinan, China.
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Kishi T. Clarification of hypertension mechanisms provided by the research of central circulatory regulation. Hypertens Res 2023; 46:1908-1916. [PMID: 37277436 DOI: 10.1038/s41440-023-01335-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 06/07/2023]
Abstract
Sympathoexcitation, under the regulatory control of the brain, plays a pivotal role in the etiology of hypertension. Within the brainstem, significant structures involved in the modulation of sympathetic nerve activity include the rostral ventrolateral medulla (RVLM), caudal ventrolateral medulla (CVLM), nucleus tractus solitarius (NTS), and paraventricular nucleus (paraventricular). The RVLM, in particular, is recognized as the vasomotor center. Over the past five decades, fundamental investigations on central circulatory regulation have underscored the involvement of nitric oxide (NO), oxidative stress, the renin-angiotensin system, and brain inflammation in regulating the sympathetic nervous system. Notably, numerous significant findings have come to light through chronic experiments conducted in conscious subjects employing radio-telemetry systems, gene transfer techniques, and knockout methodologies. Our research has centered on elucidating the role of NO and angiotensin II type 1 (AT1) receptor-induced oxidative stress within the RVLM and NTS in regulating the sympathetic nervous system. Additionally, we have observed that various orally administered AT1 receptor blockers effectively induce sympathoinhibition by reducing oxidative stress via blockade of the AT1 receptor in the RVLM of hypertensive rats. Recent advances have witnessed the development of several clinical interventions targeting brain mechanisms. Nonetheless, Future and further basic and clinical research are needed.
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Affiliation(s)
- Takuya Kishi
- Department of Graduate School of Medicine (Cardiology), International University of Health and Welfare, Okawa, Japan.
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Su Q, Yu XJ, Wang XM, Li HB, Li Y, Bai J, Qi J, Zhang N, Liu KL, Zhang Y, Zhu GQ, Kang YM. Bilateral Paraventricular Nucleus Upregulation of Extracellular Superoxide Dismutase Decreases Blood Pressure by Regulation of the NLRP3 and Neurotransmitters in Salt-Induced Hypertensive Rats. Front Pharmacol 2021; 12:756671. [PMID: 34899311 PMCID: PMC8656229 DOI: 10.3389/fphar.2021.756671] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 10/26/2021] [Indexed: 12/19/2022] Open
Abstract
Aims: Long-term salt diet induces the oxidative stress in the paraventricular nucleus (PVN) and increases the blood pressure. Extracellular superoxide dismutase (Ec-SOD) is a unique antioxidant enzyme that exists in extracellular space and plays an essential role in scavenging excessive reactive oxygen species (ROS). However, the underlying mechanism of Ec-SOD in the PVN remains unclear. Methods: Sprague-Dawley rats (150-200 g) were fed either a high salt diet (8% NaCl, HS) or normal salt diet (0.9% NaCl, NS) for 6 weeks. Each group of rats was administered with bilateral PVN microinjection of AAV-Ec-SOD (Ec-SOD overexpression) or AAV-Ctrl for the next 6 weeks. Results: High salt intake not only increased mean arterial blood pressure (MAP) and the plasma noradrenaline (NE) but also elevated the NAD(P)H oxidase activity, the NAD(P)H oxidase components (NOX2 and NOX4) expression, and ROS production in the PVN. Meanwhile, the NOD-like receptor protein 3 (NLRP3)-dependent inflammatory proteins (ASC, pro-cas-1, IL-β, CXCR, CCL2) expression and the tyrosine hydroxylase (TH) expression in the PVN with high salt diet were higher, but the GSH level, Ec-SOD activity, GAD67 expression, and GABA level were lower than the NS group. Bilateral PVN microinjection of AAV-Ec-SOD decreased MAP and the plasma NE, reduced NAD(P)H oxidase activity, the NOX2 and NOX4 expression, and ROS production, attenuated NLRP3-dependent inflammatory expression and TH, but increased GSH level, Ec-SOD activity, GAD67 expression, and GABA level in the PVN compared with the high salt group. Conclusion: Excessive salt intake not only activates oxidative stress but also induces the NLRP3-depensent inflammation and breaks the balance between inhibitory and excitability neurotransmitters in the PVN. Ec-SOD, as an essential anti-oxidative enzyme, eliminates the ROS in the PVN and decreases the blood pressure, probably through inhibiting the NLRP3-dependent inflammation and improving the excitatory neurotransmitter release in the PVN in the salt-induced hypertension.
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Affiliation(s)
- Qing Su
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
| | - Xiao-Jing Yu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
| | - Xiao-Min Wang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
| | - Hong-Bao Li
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
| | - Ying Li
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
| | - Juan Bai
- Department of Anesthesiology and Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jie Qi
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
| | - Nianping Zhang
- Department of Clinical Medicine, Medical School of Shanxi Datong University, Datong, China
| | - Kai-Li Liu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
| | - Yan Zhang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
| | - Guo-Qing Zhu
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Shaanxi Engineering and Research Center of Vaccine, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry of China, Xi'an, China
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Youwakim J, Girouard H. Inflammation: A Mediator Between Hypertension and Neurodegenerative Diseases. Am J Hypertens 2021; 34:1014-1030. [PMID: 34136907 DOI: 10.1093/ajh/hpab094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 05/03/2021] [Accepted: 06/15/2021] [Indexed: 12/14/2022] Open
Abstract
Hypertension is the most prevalent and modifiable risk factor for stroke, vascular cognitive impairment, and Alzheimer's disease. However, the mechanistic link between hypertension and neurodegenerative diseases remains to be understood. Recent evidence indicates that inflammation is a common pathophysiological trait for both hypertension and neurodegenerative diseases. Low-grade chronic inflammation at the systemic and central nervous system levels is now recognized to contribute to the physiopathology of hypertension. This review speculates that inflammation represents a mediator between hypertension and neurodegenerative diseases, either by a decrease in cerebral blood flow or a disruption of the blood-brain barrier which will, in turn, let inflammatory cells and neurotoxic molecules enter the brain parenchyma. This may impact brain functions including cognition and contribute to neurodegenerative diseases. This review will thus discuss the relationship between hypertension, systemic inflammation, cerebrovascular functions, neuroinflammation, and brain dysfunctions. The potential clinical future of immunotherapies against hypertension and associated cerebrovascular risks will also be presented.
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Affiliation(s)
- Jessica Youwakim
- Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada
- Centre interdisciplinaire de recherche sur le cerveau et l’apprentissage (CIRCA); Montreal, QC, Canada
- Groupe de Recherche sur le Système Nerveux Central, Montreal, QC, Canada
| | - Hélène Girouard
- Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada
- Centre interdisciplinaire de recherche sur le cerveau et l’apprentissage (CIRCA); Montreal, QC, Canada
- Groupe de Recherche sur le Système Nerveux Central, Montreal, QC, Canada
- Centre de recherche de l’Institut Universitaire de Gériaterie de Montréal, Montreal, QC, Canada
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Kawarazaki W, Fujita T. Kidney and epigenetic mechanisms of salt-sensitive hypertension. Nat Rev Nephrol 2021; 17:350-363. [PMID: 33627838 DOI: 10.1038/s41581-021-00399-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2021] [Indexed: 02/07/2023]
Abstract
Dietary salt intake increases blood pressure (BP) but the salt sensitivity of BP differs between individuals. The interplay of ageing, genetics and environmental factors, including malnutrition and stress, contributes to BP salt sensitivity. In adults, obesity is often associated with salt-sensitive hypertension. The children of women who experience malnutrition during pregnancy are at increased risk of developing obesity, diabetes and salt-sensitive hypertension as adults. Similarly, the offspring of mice that are fed a low-protein diet during pregnancy develop salt-sensitive hypertension in association with aberrant DNA methylation of the gene encoding type 1A angiotensin II receptor (AT1AR) in the hypothalamus, leading to upregulation of hypothalamic AT1AR and renal sympathetic overactivity. Ageing is also associated with salt-sensitive hypertension. In aged mice, promoter methylation leads to reduced kidney production of the anti-ageing factor Klotho and a decrease in circulating soluble Klotho. In the setting of Klotho deficiency, salt-induced activation of the vascular Wnt5a-RhoA pathway leads to ageing-associated salt-sensitive hypertension, potentially as a result of reduced renal blood flow and increased peripheral resistance. Thus, kidney mechanisms and aberrant DNA methylation of certain genes are involved in the development of salt-sensitive hypertension during fetal development and old age. Three distinct paradigms of epigenetic memory operate on different timescales in prenatal malnutrition, obesity and ageing.
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Affiliation(s)
- Wakako Kawarazaki
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan. .,School of Medicine, Shinshu University, Matsumoto, Japan. .,Research Center for Social Systems, Shinshu University, Matsumoto, Japan.
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9
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Cooperation of augmented calcium sensitization and increased calcium entry contributes to high blood pressure in salt-sensitive Dahl rats. Hypertens Res 2021; 44:1067-1078. [PMID: 33875859 DOI: 10.1038/s41440-021-00659-5] [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: 12/09/2020] [Revised: 02/11/2021] [Accepted: 03/14/2021] [Indexed: 11/09/2022]
Abstract
Salt hypertensive Dahl rats are characterized by sympathoexcitation and relative NO deficiency. We tested the hypothesis that the increased blood pressure (BP) response to fasudil in salt hypertensive Dahl rats is due to augmented calcium sensitization in the salt-sensitive strain and/or due to their decreased baroreflex efficiency. BP reduction after acute administration of nifedipine (an L-type voltage-dependent calcium channel blocker) or fasudil (a Rho kinase inhibitor) was studied in conscious intact rats and in rats subjected to acute NO synthase inhibition or combined blockade of the renin-angiotensin system (captopril), sympathetic nervous system (pentolinium), and NO synthase (L-NAME). Intact salt-sensitive (SS) Dahl rats fed a low-salt diet had greater BP responses to nifedipine (-31 ± 6 mmHg) or fasudil (-34 ± 7 mmHg) than salt-resistant (SR) Dahl rats (-16 ± 4 and -17 ± 2 mmHg, respectively), and a high-salt intake augmented the BP response only in SS rats. These BP responses were doubled after acute NO synthase inhibition, indicating that endogenous NO attenuates both calcium entry and calcium sensitization. Additional pentolinium administration, which minimized sympathetic compensation for the drug-induced BP reduction, magnified the BP responses to nifedipine or fasudil in all groups except for salt hypertensive SS rats due to their lower baroreflex efficiency. The BP response to the calcium channel blocker nifedipine can distinguish SS and SR rats even after calcium sensitization inhibition by fasudil, which was not seen when fasudil was administered to nifedipine-pretreated rats. Thus, enhanced calcium entry (potentiated by sympathoexcitation) in salt hypertensive Dahl rats is the abnormality that is essential for their BP increase, which was further augmented by increased calcium sensitization in salt-sensitive Dahl rats.
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Kawarazaki W, Fujita T. Role of Rho in Salt-Sensitive Hypertension. Int J Mol Sci 2021; 22:ijms22062958. [PMID: 33803946 PMCID: PMC8001214 DOI: 10.3390/ijms22062958] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 12/21/2022] Open
Abstract
A high amount of salt in the diet increases blood pressure (BP) and leads to salt-sensitive hypertension in individuals with impaired renal sodium excretion. Small guanosine triphosphatase (GTP)ase Rho and Rac, activated by salt intake, play important roles in the pathogenesis of salt-sensitive hypertension as key switches of intracellular signaling. Focusing on Rho, high salt intake in the central nervous system increases sodium concentrations of cerebrospinal fluid in salt-sensitive subjects via Rho/Rho kinase and renin-angiotensin system activation and causes increased brain salt sensitivity and sympathetic nerve outflow in BP control centers. In vascular smooth muscle cells, Rho-guanine nucleotide exchange factors and Rho determine sensitivity to vasoconstrictors such as angiotensin II (Ang II), and facilitate vasoconstriction via G-protein and Wnt pathways, leading to increased vascular resistance, including in the renal arteries, in salt-sensitive subjects with high salt intake. In the vascular endothelium, Rho/Rho kinase inhibits nitric oxide (NO) production and function, and high salt amounts further augment Rho activity via asymmetric dimethylarginine, an endogenous inhibitor of NO synthetase, causing aberrant relaxation and increased vascular tone. Rho-associated mechanisms are deeply involved in the development of salt-sensitive hypertension, and their further elucidation can help in developing effective protection and new therapies.
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Matsuo T, Miyata Y, Otsubo A, Mukae Y, Mitsunari K, Ohba K, Sakai H. Efficacy of salt reduction for managing overactive bladder symptoms: a prospective study in patients with excessive daily salt intake. Sci Rep 2021; 11:4046. [PMID: 33603133 PMCID: PMC7893030 DOI: 10.1038/s41598-021-83725-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 12/08/2020] [Indexed: 12/28/2022] Open
Abstract
This study aimed to investigate the efficacy of salt intake restriction on overactive bladder (OAB) symptoms in patients with excessive salt intake. Patients received a brochure on nutritional guidance regarding salt intake reduction and received health education every 4 weeks for 12 weeks. Data from overactive bladder symptom score (OABSS) questionnaires and frequency volume charts (FVCs) were evaluated. The daily salt intake was estimated by determining the urinary sodium and creatinine concentrations using spot urine samples. Of the 98 patients included, 71 (72.4%) successfully restricted their daily salt intake after 12 weeks (salt restricted [R] group), while 27 (27.6%) did not (salt non-restricted [N-R] group). The scores to each OABSS question and the resulting total score improved significantly in the R group; however, the individual scores remained unchanged and the total score increased in the N-R group. The FVC data indicated improved voided volumes in the R group as compared to in the N-R group. Ultimately, 17 (23.9%) patients in the R group no longer fulfilled the OAB diagnostic criteria after salt intake reduction. Thus, salt intake reduction improved urinary symptoms in patients with OAB and may be a therapeutic option for OAB in patients with excessive daily salt intakes.
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Affiliation(s)
- Tomohiro Matsuo
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Yasuyoshi Miyata
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
| | - Asato Otsubo
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Yuta Mukae
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Kensuke Mitsunari
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Kojiro Ohba
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Hideki Sakai
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
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Subramanian M, Edwards L, Melton A, Branen L, Herron A, Sivasubramanian MK, Monteiro R, Stansbury S, Balasubramanian P, Morris L, Elkholey K, Niewiadomska M, Stavrakis S. Non-invasive vagus nerve stimulation attenuates proinflammatory cytokines and augments antioxidant levels in the brainstem and forebrain regions of Dahl salt sensitive rats. Sci Rep 2020; 10:17576. [PMID: 33067477 PMCID: PMC7567801 DOI: 10.1038/s41598-020-74257-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/21/2020] [Indexed: 12/16/2022] Open
Abstract
The anti-inflammatory effects of vagus nerve stimulation are well known. It has recently been shown that low-level, transcutaneous stimulation of vagus nerve at the tragus (LLTS) reduces cardiac inflammation in a rat model of heart failure with preserved ejection fraction (HFpEF). The mechanisms by which LLTS affect the central neural circuits within the brain regions that are important for the regulation of cardiac vagal tone are not clear. Female Dahl salt-sensitive rats were initially fed with either low salt (LS) or high salt (HS) diet for a period of 6 weeks, followed by sham or active stimulation (LLTS) for 30 min daily for 4 weeks. To study the central effects of LLTS, four brainstem (SP5, NAb, NTS, and RVLM) and two forebrain sites (PVN and SFO) were examined. HS diet significantly increased the gene expression of proinflammatory cytokines in the SP5 and SFO. LLTS reversed HS diet-induced changes at both these sites. Furthermore, LLTS augmented the levels of antioxidant Nrf2 in the SP5 and SFO. Taken together, these findings suggest that LLTS has central anti-inflammatory and antioxidant properties that could mediate the neuromodulation of cardiac vagal tone in the rat model of HFpEF.
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Affiliation(s)
- Madhan Subramanian
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, 277 McElroy Hall, Stillwater, OK, 74078, USA.
| | - Laura Edwards
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, 277 McElroy Hall, Stillwater, OK, 74078, USA
| | - Avery Melton
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, 277 McElroy Hall, Stillwater, OK, 74078, USA
| | - Lyndee Branen
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, 277 McElroy Hall, Stillwater, OK, 74078, USA
| | - Angela Herron
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, 277 McElroy Hall, Stillwater, OK, 74078, USA
| | - Mahesh Kumar Sivasubramanian
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, 277 McElroy Hall, Stillwater, OK, 74078, USA
| | - Raisa Monteiro
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, 277 McElroy Hall, Stillwater, OK, 74078, USA
| | - Samantha Stansbury
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, 277 McElroy Hall, Stillwater, OK, 74078, USA
| | - Priya Balasubramanian
- Reynolds Oklahoma Center On Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Lynsie Morris
- Department of Medicine, Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Medicine, Heart Rhythm Institute, University of Oklahoma Health Sciences Center, 800 Stanton L Young Blvd, Suite 5400, Oklahoma City, OK, 73104, USA
| | - Khaled Elkholey
- Department of Medicine, Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Monika Niewiadomska
- Department of Medicine, Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Stavros Stavrakis
- Department of Medicine, Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Medicine, Heart Rhythm Institute, University of Oklahoma Health Sciences Center, 800 Stanton L Young Blvd, Suite 5400, Oklahoma City, OK, 73104, USA.
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Kumar V, Yang C, Cowley AW. Temporal Expression and Cellular Localization of PAPPA2 in the Developing Kidney of Rat. J Histochem Cytochem 2020; 68:209-222. [PMID: 31989854 DOI: 10.1369/0022155420904478] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PAPPA2 is a metalloproteinase which cleaves insulin-like growth factor binding protein (IGFBP)-3 and IGFBP-5, and its role in pregnancy and postnatal growth is primarily studied. Using exclusion mapping, we reported a subcongenic (26-P) rat where a 0.71-Mbp region containing the pregnancy-associated plasma protein a2 (Pappa2) allele of salt-insensitive Brown Norway (BN) was introgressed into Dahl saltsensitive (SS) genetic background, resulting in the reduction of salt sensitivity. Pappa2 was differentially expressed in the adult kidney of 26-P and SS rats. Here, the expression and cellular localization of Pappa2 in embryonic and postnatal kidneys of 26-P and SS rats were examined. Pappa2 mRNA expression was 5-fold higher in the embryonic kidney (day 20.5) of the 26-P rat compared with the SS rat. Pappa2 mRNA expression progressively increased with the development of kidney, reaching a peak at postnatal day 5 before trending downward in subsequent stages of development in both strains. At all tested time points, Pappa2 remained higher in the 26-P compared with the SS rat kidney. Immunohistochemistry studies localized PAPPA2 in the ureteric bud (UB) and distal part of S-shaped body. PAPPA2 was colocalized with IGFBP-5 in the UB and Na+/K+/2Cl- cotransporter-stained tubules, respectively. Future studies are needed to determine the role of Pappa2 in kidney development and mechanistic pathways involved in this process.
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Affiliation(s)
- Vikash Kumar
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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Jiang WY, Huo JY, Chen C, Chen R, Ge TT, Chang Q, Hu JW, Geng J, Jiang ZX, Shan QJ. Renal denervation ameliorates post-infarction cardiac remodeling in rats through dual regulation of oxidative stress in the heart and brain. Biomed Pharmacother 2019; 118:109243. [DOI: 10.1016/j.biopha.2019.109243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/08/2019] [Accepted: 07/17/2019] [Indexed: 01/06/2023] Open
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Brain perivascular macrophages contribute to the development of hypertension in stroke-prone spontaneously hypertensive rats via sympathetic activation. Hypertens Res 2019; 43:99-110. [PMID: 31541222 DOI: 10.1038/s41440-019-0333-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 08/20/2019] [Accepted: 08/21/2019] [Indexed: 11/09/2022]
Abstract
Hypertension is associated with systemic inflammation. The activation of the sympathetic nervous system is critically involved in the pathogenesis of hypertension. Brain perivascular macrophages (PVMs) can be affected by circulating inflammatory cytokines, and the contribution of brain PVMs to sympathoexcitation has been demonstrated in a heart failure model. We thus investigated whether brain PVMs contribute to the development of hypertension through sympathoexcitation. Stroke-prone spontaneously hypertensive rats (SHRSP) developed hypertension over an 8-week period from 4 to 12 weeks of age. The number of brain PVMs and plasma interleukin-1β levels significantly increased at the ages of 8 and 12 weeks in SHRSP compared with normotensive Wistar-Kyoto rats (WKY). To determine the contribution of brain PVMs to blood pressure elevation, we intracerebroventricularly injected liposome-encapsulated clodronate, which eliminates macrophages by inducing apoptosis, into 8-week-old rats; we then assessed its effects in 10-week-old rats. Clodronate treatment attenuated the increase in mean blood pressure in SHRSP but not in WKY. Clodronate treatment reduced the depressor effect of hexamethonium, an index of sympathetic activity; it also reduced neuronal activity in sympathetic regulatory nuclei such as the hypothalamic paraventricular nucleus and rostral ventrolateral medulla and reduced the expression of cyclooxygenase-2 and prostaglandin E2, a downstream pathway in activated macrophages, in SHRSP but not in WKY. Furthermore, clodronate treatment attenuated the increase in blood pressure and renal sympathetic nerve activity in response to an acute intravenous injection of interleukin-1β in WKY. In conclusion, brain PVMs contribute to the development of hypertension via sympathetic activation. PVMs may be activated by increased levels of circulating interleukin-1β.
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Evaluation of the pathophysiological mechanisms of salt-sensitive hypertension. Hypertens Res 2019; 42:1848-1857. [PMID: 31541221 DOI: 10.1038/s41440-019-0332-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 08/24/2019] [Accepted: 08/27/2019] [Indexed: 12/23/2022]
Abstract
The currently available data have indicated that dietary salt is directly correlated with blood pressure (BP) and the occurrence of hypertension. However, the salt sensitivity of BP is different in each individual. Genetic factors and environmental factors influence the salt sensitivity of BP. Obesity, stress, and aging are strongly associated with increased BP salt sensitivity. Indeed, a complex and interactive genetic and environmental system can determine an individual's BP salt sensitivity. However, the genetic/epigenetic determinants leading to salt sensitivity of BP are still challenging to identify primarily because lifestyle-related diseases, including hypertension, usually become a medical problem during adulthood, although their causes may be attributed to the earlier stages of ontogeny. The association between distinct developmental periods involves changes in gene expression, which include epigenetic phenomena. The role of epigenetic modification in the development of salt-sensitive hypertension is presently under investigation. Recently, we identified aberrant DNA methylation in the context of prenatally programmed hypertension. In this review, we summarize the existing knowledge regarding the pathophysiological mechanisms of salt-sensitive hypertension. Additionally, we discuss the contribution of epigenetic mechanisms in the development of salt-sensitive hypertension.
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TLR4 participates in sympathetic hyperactivity Post-MI in the PVN by regulating NF-κB pathway and ROS production. Redox Biol 2019; 24:101186. [PMID: 30978539 PMCID: PMC6460304 DOI: 10.1016/j.redox.2019.101186] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 03/14/2019] [Accepted: 03/28/2019] [Indexed: 01/01/2023] Open
Abstract
Sympathetic nerve hyperactivity is a primary reason for fatal ventricular arrhythmias (VAs) following myocardial infarction (MI). Pro-inflammatory cytokines produced in the paraventricular nucleus (PVN) post-MI are associated with sympathetic overexcitation; however, the precise mechanism needs further investigation. Our aim was to explore the mechanism of toll-like receptor 4 (TLR4) and its downstream molecular pathway in mediating sympathetic activity post-MI within the PVN. A rat MI model was developed via left anterior descending coronary artery ligation. TLR4 was primarily localized in microglia and increased markedly within the PVN at 3 days in MI rats. Sympathoexcitation also increased, as indicated by high levels of renal sympathetic nerve activity (RSNA) and norepinephrine (NE) concentration. TLR4 knockdown via shRNA microinjection to the PVN resulted in decreased activation of Fos protein (+) neurons in the PVN and peripheral sympathetic nerve activity. TLR4 knockdown also exhibited a lower arrhythmia score following programmed electrical stimulation than those treated with MI surgery only, indicating that the knockdown of TLR4 decreased the incidence of malignant ventricular arrhythmias following MI. LPS-induced inflammatory response was analyzed to explore the underlying mechanism of TLR4 in sympathetic hyperactivity. High levels of NF-κB protein, the pro-inflammatory cytokines IL-1β and TNF-α, and ROS production were observed in the LPS group. PVN-targeted injection of the NF-κB inhibitor PDTC attenuated NF-κB expression and sympathetic activity. Taken together, the results suggested that knockdown of microglial TLR4 within the PVN decreased sympathetic hyperactivity and subsequent VAs post-MI. The downstream NF-κB pathway and ROS production participated in the process. Interventions targeting TLR4 signaling in the PVN may be a novel approach to ameliorate the incidence of VAs post-MI.
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Matsuo T, Miyata Y, Sakai H. Effect of salt intake reduction on nocturia in patients with excessive salt intake. Neurourol Urodyn 2019; 38:927-933. [PMID: 30706965 DOI: 10.1002/nau.23929] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/04/2018] [Accepted: 12/26/2018] [Indexed: 12/29/2022]
Abstract
AIMS To assess the efficacy of salt reduction for improving nocturia in patients with high salt intake. METHODS Changes in lower urinary symptoms and frequency volume chart by salt intake (men: 8 g/day; women: ≥7 g/day) were analyzed in this prospective study. Patients were instructed to use a brochure for salt intake restriction via interview once every four weeks. The daily salt intake was estimated by using spot urine samples. RESULTS Two-hundred twenty-three (69.5%) patients were successful in reducing their daily salt intake (S group), whereas 98 (30.5%) patients failed to reduce their salt intake (F group). In the S group, nocturia improved from 2.3 ± 0.9 to 1.4 ± 1.0, and nocturnal polyuria index (NPi) improved from 30.2 ± 7.5 to 27.7 ± 7.3% (P < 0.001). In the Core Lower Urinary Tract Symptom Score (CLSS) of the S group, Q3 (urgency) improved from 1.0 ± 1.0 to 0.9 ± 1.0 (P = 0.001); Q1 (diurnal frequency) (P < 0.001), and Q2 (nocturia) also improved (P < 0.001). Moreover, the quality of life parameter improved significantly (P < 0.001). The patients in the F group did not have improvements in any symptom during the study period. CONCLUSIONS Patients with nocturia who also have high salt intake should be advised to reduce their salt intake, as a lifestyle modification. Our results support the importance of randomized clinical trials with larger populations and the appropriate inclusion/exclusion criteria to conclude the clinical usefulness of salt reduction in this patient cohort.
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Affiliation(s)
- Tomohiro Matsuo
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yasuyoshi Miyata
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Hideki Sakai
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Chronic Intracerebroventricular Infusion of Metformin Inhibits Salt-Sensitive Hypertension via Attenuation of Oxidative Stress and Neurohormonal Excitation in Rat Paraventricular Nucleus. Neurosci Bull 2018; 35:57-66. [PMID: 30426340 DOI: 10.1007/s12264-018-0308-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 09/26/2018] [Indexed: 01/15/2023] Open
Abstract
Metformin (MET), an antidiabetic agent, also has antioxidative effects in metabolic-related hypertension. This study was designed to determine whether MET has anti-hypertensive effects in salt-sensitive hypertensive rats by inhibiting oxidative stress in the hypothalamic paraventricular nucleus (PVN). Salt-sensitive rats received a high-salt (HS) diet to induce hypertension, or a normal-salt (NS) diet as control. At the same time, they received intracerebroventricular (ICV) infusion of MET or vehicle for 6 weeks. We found that HS rats had higher oxidative stress levels and mean arterial pressure (MAP) than NS rats. ICV infusion of MET attenuated MAP and reduced plasma norepinephrine levels in HS rats. It also decreased reactive oxygen species and the expression of subunits of NAD(P)H oxidase, improved the superoxide dismutase activity, reduced components of the renin-angiotensin system, and altered neurotransmitters in the PVN. Our findings suggest that central MET administration lowers MAP in salt-sensitive hypertension via attenuating oxidative stress, inhibiting the renin-angiotensin system, and restoring the balance between excitatory and inhibitory neurotransmitters in the PVN.
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Bądzyńska B, Baranowska I, Gawryś O, Sadowski J. Evidence against a crucial role of renal medullary perfusion in blood pressure control of hypertensive rats. J Physiol 2018; 597:211-223. [PMID: 30334256 DOI: 10.1113/jp276342] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 10/17/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The development of new effective methods of treating arterial hypertension is hindered by uncertainty regarding its causes. According to one widespread concept hypertension is caused by abnormal blood circulation in the kidney, specifically by reduction of blood flow through the kidney medulla; however, this causal relationship has never been rigorously verified. We investigated whether in rats with three different forms of experimental hypertension prolonged selective elevation of renal medullary blood flow using local infusion of the vasodilator bradykinin would lower arterial pressure. We found that increasing medullary blood flow by almost 50% did not result in alleviation of hypertension, which argues against a causal role of such changes in the control of arterial pressure and suggests that attempts at improving renal medullary circulation are not likely to be a promising approach to combating hypertension. ABSTRACT The crucial role of renal medullary blood flow (MBF) in the control of arterial pressure (MAP) has been widely accepted but not rigorously verified. We examined the effects of experimental selective MBF elevation on MAP, medullary tissue hypertonicity and renal excretion in hypertensive rats. We used three hypertensive rat models: (1) rats with hypertension induced by chronic angiotensin II infusions (AngII model), (2) rats with hypertension induced by unilateral nephrectomy followed by high salt diet (HS/UNX), and (3) spontaneously hypertensive rats (SHR). In acute experiments, MBF (laser-Doppler measurement) was selectively increased with an intramedullary infusion of bradykinin (Bk) at 0.27 mg h-1 kg-1 BW over 4 h. MAP, renal artery blood flow (Transonic probe) and renal excretion parameters were measured simultaneously. In chronic studies with AngII and HS/UNX rats, Bk was infused over 2 weeks and MAP (telemetry probe) and renal excretion were repeatedly determined. In acute studies, with AngII, SHR and HS/UNX groups, Bk infusion caused a 47% increase in MBF (P < 0.01-0.001), whereas solvent infusion was without effect. During the experiments MAP decreased slightly and to the same extent with Bk and solvent infusion. Medullary tissue osmolality and [Na+ ] were lower in Bk- than in solvent-infused AngII rats and in SHR. Two weeks of intramedullary Bk infusion tested in AngII and HS/UNX rats did not alter MAP or renal excretion; though in the latter group a significant MBF increase and medullary hypertonicity decrease was observed. Since no decrease in MAP in hypertensive rats was seen with Bk-induced major renal medullary hyperperfusion or with a wash-out of medullary solutes, our data argue against a crucial role of MBF in the pathogenesis of arterial hypertension.
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Affiliation(s)
- Bożena Bądzyńska
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Centre , Polish Academy of Sciences, 5 Pawińskiego St, 02-106, Warsaw, Poland
| | - Iwona Baranowska
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Centre , Polish Academy of Sciences, 5 Pawińskiego St, 02-106, Warsaw, Poland
| | - Olga Gawryś
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Centre , Polish Academy of Sciences, 5 Pawińskiego St, 02-106, Warsaw, Poland
| | - Janusz Sadowski
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Centre , Polish Academy of Sciences, 5 Pawińskiego St, 02-106, Warsaw, Poland
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Kawakami-Mori F, Nishimoto M, Reheman L, Kawarazaki W, Ayuzawa N, Ueda K, Hirohama D, Kohno D, Oba S, Shimosawa T, Marumo T, Fujita T. Aberrant DNA methylation of hypothalamic angiotensin receptor in prenatal programmed hypertension. JCI Insight 2018; 3:95625. [PMID: 30385711 DOI: 10.1172/jci.insight.95625] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 09/27/2018] [Indexed: 12/12/2022] Open
Abstract
Maternal malnutrition, which causes prenatal exposure to excessive glucocorticoid, induces adverse metabolic programming, leading to hypertension in offspring. In offspring of pregnant rats receiving a low-protein diet or dexamethasone, a synthetic glucocorticoid, mRNA expression of angiotensin receptor type 1a (Agtr1a) in the paraventricular nucleus (PVN) of the hypothalamus was upregulated, concurrent with reduced expression of DNA methyltransferase 3a (Dnmt3a), reduced binding of DNMT3a to the Agtr1a gene, and DNA demethylation. Salt loading increased BP in both types of offspring, suggesting that elevated hypothalamic Agtr1a expression is epigenetically modulated by excessive glucocorticoid and leads to adult-onset salt-sensitive hypertension. Consistent with this, dexamethasone treatment of PVN cells upregulated Agtr1a, while downregulating Dnmt3a, and decreased DNMT3a binding and DNA demethylation at the Agtr1a locus. In addition, Dnmt3a knockdown upregulated Agtr1a independently of dexamethasone. Hypothalamic neuron-specific Dnmt3a-deficient mice exhibited upregulation of Agtr1a in the PVN and salt-induced BP elevation without dexamethasone treatment. By contrast, dexamethasone-treated Agtr1a-deficient mice failed to show salt-induced BP elevation, despite reduced expression of Dnmt3a. Thus, epigenetic modulation of hypothalamic angiotensin signaling contributes to salt-sensitive hypertension induced by prenatal glucocorticoid excess in offspring of mothers that are malnourished during pregnancy.
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Affiliation(s)
- Fumiko Kawakami-Mori
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan.,Division of Endocrinology, Mitsui Memorial Hospital, Tokyo, Japan
| | - Mitsuhiro Nishimoto
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan
| | - Latapati Reheman
- Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Narita Hospital IUHW, Tokyo, Japan
| | - Wakako Kawarazaki
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan
| | - Nobuhiro Ayuzawa
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan
| | - Kohei Ueda
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan
| | - Daigoro Hirohama
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan
| | - Daisuke Kohno
- Advanced Scientific Research Leaders Development Unit, Gunma University, Gunma, Japan
| | - Shigeyoshi Oba
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan
| | - Tatsuo Shimosawa
- Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Narita Hospital IUHW, Tokyo, Japan
| | - Takeshi Marumo
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Tokyo, Japan
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Gong X, Han X, Lu X, Chen J, Huang J, Kelly TN, Chen CS, He J, Gu D, Chen S. Association of Kir genes with blood pressure responses to dietary sodium intervention: the GenSalt study. Hypertens Res 2018; 41:1045-1053. [PMID: 30323262 DOI: 10.1038/s41440-018-0113-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/19/2018] [Accepted: 05/12/2018] [Indexed: 12/19/2022]
Abstract
Blood pressure (BP) responses to dietary sodium intervention vary among individuals. The inwardly rectifying potassium channel (Kir) is a potassium-selective ion channel that allows potassium ions to move more easily into rather than out of the cell. We aimed to investigate the associations of Kir genes with BP responses to dietary sodium intervention. A 7-day low-sodium intervention followed by a 7-day high-sodium intervention was conducted among 1906 participants. BP measurements were obtained at baseline and during each dietary intervention. Both single-marker and gene-based analyses were performed to explore the associations between Kir gene variants and BP responses to dietary sodium interventions. The genetic risk score (GRS) was used to assess the cumulative effect of the variants on the BP response to the sodium interventions. During the low-sodium intervention, markers rs858009, rs2835904, and rs860795 in KCNJ6 were significantly associated with the systolic BP (SBP) response (P = 8.82 × 10-6, 3.32 × 10-6, and 2.39 × 10-4, respectively), whereas rs858009 and rs2835904 were significantly correlated with the mean arterial pressure (MAP) response (P = 1.64 × 10-4 and 2.72 × 10-4, respectively). Marker rs2836023 showed a significant association with the SBP response (P = 5.72 × 10-5) to the high-sodium intervention. The GRS stratified by quartile grouping or as a continuous variable was associated with the BP response to the sodium interventions. Gene-based analyses consistently revealed that KCNJ6 was significantly associated with the BP response to the sodium interventions. These findings suggest that KCNJ6 may contribute to variation of BP responses to dietary sodium interventions. Future studies are warranted to confirm these findings and to identify functional variants for salt sensitivity.
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Affiliation(s)
- Xinyuan Gong
- Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xikun Han
- Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiangfeng Lu
- Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jing Chen
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Jianfeng Huang
- Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tanika N Kelly
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Chung-Shiuan Chen
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Jiang He
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Dongfeng Gu
- Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shufeng Chen
- Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
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Jackson KL, Marques FZ, Lim K, Davern PJ, Head GA. Circadian Differences in the Contribution of the Brain Renin-Angiotensin System in Genetically Hypertensive Mice. Front Physiol 2018; 9:231. [PMID: 29615926 PMCID: PMC5868475 DOI: 10.3389/fphys.2018.00231] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/01/2018] [Indexed: 11/21/2022] Open
Abstract
Objective: Genetically hypertensive BPH/2J mice are recognized as a neurogenic model of hypertension, primarily based on sympathetic overactivity and greater neuronal activity in cardiovascular regulatory brain regions. Greater activity of the central renin angiotensin system (RAS) and reactive oxygen species (ROS) reportedly contribute to other models of hypertension. Importantly the peripheral RAS contributes to the hypertension in BPH/2J mice, predominantly during the dark period of the 24 h light cycle. The aim of the present study was to determine whether central AT1 receptor stimulation and the associated ROS signaling contribute to hypertension in BPH/2J mice in a circadian dependent manner. Methods: Blood pressure (BP) was measured in BPH/2J and normotensive BPN/3J mice (n = 7–8) via pre-implanted telemetry devices. Acute intracerebroventricular (ICV) microinjections of AT1 receptor antagonist, candesartan, and the superoxide dismutase (SOD) mimetic, tempol, were administered during the dark and light period of the 24 h light cycle via a pre-implanted ICV guide cannula. In separate mice, the BP effect of ICV infusion of the AT1 receptor antagonist losartan for 7 days was compared with subcutaneous infusion to determine the contribution of the central RAS to hypertension in BPH/2J mice. Results: Candesartan administered ICV during the dark period induced depressor responses which were 40% smaller in BPH/2J than BPN/3J mice (Pstrain < 0.05), suggesting AT1 receptor stimulation may contribute less to BP maintenance in BPH/2J mice. During the light period candesartan had minimal effect on BP in either strain. ICV tempol had comparable effects on BP between strains during the light and dark period (Pstrain > 0.08), suggesting ROS signaling is also not contributing to the hypertension in BPH/2J mice. Chronic ICV administration of losartan (22 nmol/h) had minimal effect on BPN/3J mice. By contrast in BPH/2J mice, both ICV and subcutaneously administered losartan induced similar hypotensive responses (−12.1 ± 1.8 vs. −14.7 ± 1.8 mmHg, Proute = 0.31). Conclusion: While central effects of peripheral losartan cannot be excluded, we suggest the hypotensive effect of chronic ICV losartan was likely peripherally mediated. Thus, based on both acute and chronic AT1 receptor inhibition and acute ROS inhibition, our findings suggest that greater activation of central AT1 receptors or ROS are unlikely to be mediating the hypertension in BPH/2J mice.
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Affiliation(s)
- Kristy L Jackson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia
| | - Francine Z Marques
- Department of Pharmacology, Monash University, Victoria, VIC, Australia.,Heart Failure Research Group, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia
| | - Kyungjoon Lim
- Neuropharmacology Laboratory, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia.,Department of Physiology, Anatomy and Microbiology, Latrobe University, Bundoora, VIC, Australia
| | - Pamela J Davern
- Neuropharmacology Laboratory, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia
| | - Geoffrey A Head
- Neuropharmacology Laboratory, Baker Heart and Diabetes Research Institute, Melbourne, VIC, Australia.,Department of Pharmacology, Monash University, Victoria, VIC, Australia
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24
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Mui RK, Fernandes RN, Garver HG, Van Rooijen N, Galligan JJ. Macrophage-dependent impairment of α 2-adrenergic autoreceptor inhibition of Ca 2+ channels in sympathetic neurons from DOCA-salt but not high-fat diet-induced hypertensive rats. Am J Physiol Heart Circ Physiol 2018; 314:H863-H877. [PMID: 29351460 DOI: 10.1152/ajpheart.00536.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
DOCA-salt and obesity-related hypertension are associated with inflammation and sympathetic nervous system hyperactivity. Prejunctional α2-adrenergic receptors (α2ARs) provide negative feedback to norepinephrine release from sympathetic nerves through inhibition of N-type Ca2+ channels. Increased neuronal norepinephrine release in DOCA-salt and obesity-related hypertension occurs through impaired α2AR signaling; however, the mechanisms involved are unclear. Mesenteric arteries are resistance arteries that receive sympathetic innervation from the superior mesenteric and celiac ganglia (SMCG). We tested the hypothesis that macrophages impair α2AR-mediated inhibition of Ca2+ channels in SMCG neurons from DOCA-salt and high-fat diet (HFD)-induced hypertensive rats. Whole cell patch-clamp methods were used to record Ca2+ currents from SMCG neurons maintained in primary culture. We found that DOCA-salt, but not HFD-induced, hypertension caused macrophage accumulation in mesenteric arteries, increased SMCG mRNA levels of monocyte chemoattractant protein-1 and tumor necrosis factor-α, and impaired α2AR-mediated inhibition of Ca2+ currents in SMCG neurons. α2AR dysfunction did not involve changes in α2AR expression, desensitization, or downstream signaling factors. Oxidative stress impaired α2AR-mediated inhibition of Ca2+ currents in SMCG neurons and resulted in receptor internalization in human embryonic kidney-293T cells. Systemic clodronate-induced macrophage depletion preserved α2AR function and lowered blood pressure in DOCA-salt rats. HFD caused hypertension without obesity in Sprague-Dawley rats and hypertension with obesity in Dahl salt-sensitive rats. HFD-induced hypertension was not associated with inflammation in SMCG and mesenteric arteries or α2AR dysfunction in SMCG neurons. These results suggest that macrophage-mediated α2AR dysfunction in the mesenteric circulation may only be relevant to mineralocorticoid-salt excess. NEW & NOTEWORTHY Here, we identify a contribution of macrophages to hypertension development through impaired α2-adrenergic receptor (α2AR)-mediated inhibition of sympathetic nerve terminal Ca2+ channels in DOCA-salt hypertensive rats. Impaired α2AR function may involve oxidative stress-induced receptor internalization. α2AR dysfunction may be unique to mineralocorticoid-salt excess, as it does not occur in obesity-related hypertension.
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Affiliation(s)
- Ryan K Mui
- Department of Physiology, Michigan State University , East Lansing, Michigan
| | - Roxanne N Fernandes
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - Hannah G Garver
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - Nico Van Rooijen
- Department of Molecular Cell Biology, Vrije Universiteit Medical Center , Amsterdam , The Netherlands
| | - James J Galligan
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan.,Neuroscience Program, Michigan State University , East Lansing, Michigan
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25
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Abstract
PURPOSE OF REVIEW The major health issue of being overweight or obese relates to the development of hypertension, insulin resistance and diabetic complications. One of the major underlying factors influencing the elevated blood pressure in obesity is increased activity of the sympathetic nerves to particular organs such as the kidney. RECENT FINDINGS There is now convincing evidence from animal studies that major signals such as leptin and insulin have a sympathoexcitatory action in the hypothalamus to cause hypertension. Recent studies suggest that this may involve 'neural plasticity' within hypothalamic signalling driven by central actions of leptin mediated via activation of melanocortin receptor signalling and activation of brain neurotrophic factors. This review describes the evidence to support the contribution of the SNS to obesity related hypertension and the major metabolic and adipokine signals.
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26
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Lu P, Jiang SJ, Pan H, Xu AL, Wang GH, Ma CL, Shi Z. Short hairpin RNA interference targeting interleukin 1 receptor type I in the paraventricular nucleus attenuates hypertension in rats. Pflugers Arch 2017; 470:439-448. [PMID: 29143938 DOI: 10.1007/s00424-017-2081-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/11/2017] [Accepted: 10/16/2017] [Indexed: 01/08/2023]
Abstract
Blood pressure is controlled by tonic sympathetic activities, excessive activation of which contributes to the pathogenesis and progression of hypertension. Interleukin (IL)-1β in the paraventricular nucleus (PVN) is involved in sympathetic overdrive and hypertension. Here, we investigated the therapeutic effects of IL-1 receptor type I (IL-1R1) gene silencing in the PVN on hypertension. Recombinant lentivirus vectors expressing a short hairpin RNA (shRNA) targeting IL-1R1 (Lv-shR-IL-1R1) or a control shRNA were microinjected into PVN of spontaneously hypertensive rats (SHRs) and normotensive WKY rats. The fluorescence of green fluorescent protein-labelled vectors appeared at 2 weeks after injection and persisted for at least 8 weeks. IL-1R1 protein expression in the PVN was reduced 4 weeks after Lv-shR-IL-1R1 injection in SHRs. IL-1R1 interference also reduced basal sympathetic activity, cardiac sympathetic afferent reflex in SHRs. Depressor effects were observed from week 2 to 10 after Lv-shR-IL-1R1 treatment in SHRs, with the most prominent effects seen at the end of week 4. Furthermore, Lv-shR-IL-1R1 treatment decreased the ratio of left ventricular weight to body weight and cross-sectional areas of myocardial cells in SHRs. Additionally, Lv-shR-IL-1R1 treatment prevented an increase in superoxide anion and pro-inflammatory cytokines (PICs, TNF-α and IL-1β) in the PVN of SHR, and upregulated anti-inflammatory cytokine (AIC, IL-10) expression. These results indicate that shRNA interference targeting IL-1R1 in the PVN decreases arterial blood pressure, attenuates excessive sympathetic activity and cardiac sympathetic afferent reflex, and improves myocardial remodelling in SHRs by restoring the balance between PICs and AICs to attenuate oxidative stress.
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Affiliation(s)
- Peng Lu
- Department of Education, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, 264003, China.,Shandong Province Key Laboratory of Stroke, Yantai, 264003, China
| | - Shu-Jun Jiang
- Department of Physiology, Binzhou Medical University, 346 Guanhai Rd, Laishan District, Yantai, Shandong Province, 264003, China
| | - Hong Pan
- Department of Physiology, Binzhou Medical University, 346 Guanhai Rd, Laishan District, Yantai, Shandong Province, 264003, China
| | - Ai-Li Xu
- Department of Physiology, Binzhou Medical University, 346 Guanhai Rd, Laishan District, Yantai, Shandong Province, 264003, China
| | - Gui-Hua Wang
- Experimental Teaching Management Center, Binzhou Medical University, Yantai, 264003, China
| | - Chun-Lei Ma
- Department of Physiology, Binzhou Medical University, 346 Guanhai Rd, Laishan District, Yantai, Shandong Province, 264003, China.,Shandong Province Key Laboratory of Stroke, Yantai, 264003, China
| | - Zhen Shi
- Department of Physiology, Binzhou Medical University, 346 Guanhai Rd, Laishan District, Yantai, Shandong Province, 264003, China.
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27
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McGowan CL, Proctor DN, Swaine I, Brook RD, Jackson EA, Levy PD. Isometric Handgrip as an Adjunct for Blood Pressure Control: a Primer for Clinicians. Curr Hypertens Rep 2017; 19:51. [PMID: 28528376 DOI: 10.1007/s11906-017-0748-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Considered a global health crisis by the World Health Organization, hypertension (HTN) is the leading risk factor for death and disability. The majority of treated patients do not attain evidence-based clinical targets, which increases the risk of potentially fatal complications. HTN is the most common chronic condition seen in primary care; thus, implementing therapies that lower and maintain BP to within-target ranges is of tremendous public health importance. Isometric handgrip (IHG) training is a simple intervention endorsed by the American Heart Association as a potential adjuvant BP-lowering treatment. With larger reductions noted in HTN patients, IHG training may be especially beneficial for those who (a) have difficulties continuing or increasing drug-based treatment; (b) are unable to attain BP control despite optimal treatment; (c) have pre-HTN or low-risk stage I mild HTN; and (d) wish to avoid medications or have less pill burden. IHG training is not routinely prescribed in clinical practice. To shift this paradigm, we focus on (1) the challenges of current HTN management strategies; (2) the effect of IHG training; (3) IHG prescription; (4) characterizing the population for whom it works best; (5) clinical relevance; and (6) important next steps to foster broader implementation by clinical practitioners.
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Affiliation(s)
- Cheri L McGowan
- Department of Kinesiology, Faculty of Human Kinetics, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada. .,Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA. .,School of Medicine, Department of Emergency Medicine, Wayne State University, Detroit, MI, USA.
| | - David N Proctor
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA
| | - Ian Swaine
- Department of Life & Sport Sciences, University of Greenwich, Medway Campus, London, UK
| | - Robert D Brook
- Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Elizabeth A Jackson
- Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Phillip D Levy
- School of Medicine, Department of Emergency Medicine, Wayne State University, Detroit, MI, USA
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28
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Basgut B, Whidden MA, Kirichenko N, Woods M, Erdos B, Scarpace PJ, Tümer N. Effect of High-Salt Diet on Age-Related High Blood Pressure and Hypothalamic Redox Signaling. Pharmacology 2017; 100:105-114. [DOI: 10.1159/000472259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 03/24/2017] [Indexed: 01/07/2023]
Abstract
Aim: The aim of this study was to investigate the effect of a high salt (HS) diet on age-related changes in blood pressure (BP) and the possible role played by regulatory central mechanisms. Methods: Young (5 months) and old (27 months) male Fischer 344 × Brown Norway (F344/BN) rats were fed standard chow or 8% HS diet for 12 days. BP and heart rate (HR) were measured by telemetry. Results: Mean arterial BP (MAP) was significantly elevated in old rats during the day and night when compared with young animals. The HS diet further elevated MAP in both age groups, and the increase was more pronounced in the old animals, while HR was not altered by age or HS diet. In addition, cardiovascular responses to restraint stress were diminished in the old when compared with the young and were unchanged with HS diet in either age group. Both age and the HS diet elevated the adrenomedullary mRNA levels of tyrosine hydroxylase, an indicator for sympathoexcitation. HS diet enhanced intracerebroventricular angiotensin II (AngII)-induced BP and HR elevations in both age groups. AngII type 1 receptor mRNA increased significantly in the hypothalamus with age and HS diet. Furthermore, hypothalamic p22phox mRNA and gp91phox protein, subunits of NADPH oxidase, as well as NADPH oxidase activity increased with the HS diet in the old animals, whereas antioxidant enzymes that decreased with age yet remained unaltered with the HS diet. Conclusion: Our findings indicate that sensitivity of BP to HS diet increases with age, and that central AngII-induced pressor responses are diminished in old rats compared with the young both under control conditions and during HS diet treatment. These changes are paralleled by increases in the expression and NADPH oxidase activity in the hypothalamus, possibly leading to central oxidative stress-mediated sympathoexcitation and high BP.
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29
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Hydrogen sulfide in paraventricular nucleus attenuates blood pressure by regulating oxidative stress and inflammatory cytokines in high salt-induced hypertension. Toxicol Lett 2017; 270:62-71. [DOI: 10.1016/j.toxlet.2017.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/22/2017] [Accepted: 02/05/2017] [Indexed: 11/21/2022]
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30
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Li P, Huang PP, Yang Y, Liu C, Lu Y, Wang F, Sun W, Kong XQ. Renal sympathetic denervation attenuates hypertension and vascular remodeling in renovascular hypertensive rats. J Appl Physiol (1985) 2017; 122:121-129. [PMID: 27742806 DOI: 10.1152/japplphysiol.01019.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 09/26/2016] [Accepted: 10/09/2016] [Indexed: 02/07/2023] Open
Abstract
Li P, Huang P, Yang Y, Liu C, Lu Y, Wang F, Sun W, Kong X. Renal sympathetic denervation attenuates hypertension and vascular remodeling in renovascular hypertensive rats. J Appl Physiol 122: 121–129, 2017. First published October 14, 2016; doi: 10.1152/japplphysiol.01019.2015 .—Sympathetic activity is enhanced in patients with essential or secondary hypertension, as well as in various hypertensive animal models. Therapeutic targeting of sympathetic activation is considered an effective antihypertensive strategy. We hypothesized that renal sympathetic denervation (RSD) attenuates hypertension and improves vascular remodeling and renal disease in the 2-kidney, 1-clip (2K1C) rat model. Rats underwent 2K1C modeling or sham surgery; then rats underwent RSD or sham surgery 4 wk later, thus resulting in four groups (normotensive-sham, normotensive-RSD, 2K1C-sham, and 2K1C-RSD). Norepinephrine was measured by ELISA. Echocardiography was used to assess heart function. Fibrosis and apoptosis were assessed by Masson and TUNEL staining. Changes in mean arterial blood pressure in response to hexamethonium and plasma norepinephrine levels were used to evaluate basal sympathetic nerve activity. The 2K1C modeling success rate was 86.8%. RSD reversed the elevated systolic blood pressure induced by 2K1C, but had no effect on body weight. Compared with rats in the 2K1C-sham group, rats in the 2K1C-RSD group showed lower left ventricular mass/body weight ratio, interventricular septal thickness in diastole, left ventricular end-systolic diameter, and left ventricular posterior wall thickness in systole, whereas fractional shortening and ejection fraction were higher. Right kidney apoptosis and left kidney hypertrophy were not changed by RSD. Arterial fibrosis was lower in animals in the 2K1C-RSD group compared with those in the 2K1C-sham group. RSD reduced plasma norepinephrine and basal sympathetic activity in rats in the 2K1C-RSD group compared with rats in the 2K1C-sham group. These results suggest a possible clinical efficacy of RSD for renovascular hypertension. NEW & NOTEWORTHY The effects of renal sympathetic denervation (RSD) on hypertension, cardiac function, vascular fibrosis, and renal apoptosis were studied in the 2K1C rat model. Results showed that RSD attenuated hypertension, improved vascular remodeling, and reduced vascular fibrosis through decreased sympathetic activity in the 2K1C rat model, but it did not change the kidney size, renal apoptosis, or renal caspase-3 expression. These results could suggest possible clinical efficacy of RSD for renovascular hypertension.
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Affiliation(s)
- Peng Li
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Peoples Republic of China
| | - Pei-Pei Huang
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Peoples Republic of China
| | - Yun Yang
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Peoples Republic of China
| | - Chi Liu
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Peoples Republic of China
| | - Yan Lu
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Peoples Republic of China
| | - Fang Wang
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Peoples Republic of China
| | - Wei Sun
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Peoples Republic of China
| | - Xiang-Qing Kong
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Peoples Republic of China
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31
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Gamella-Pozuelo L, Grande MT, Clemente-Lorenzo M, Murillo-Gómez C, De Pablo F, López-Novoa JM, Hernández-Sánchez C. Tyrosine hydroxylase haploinsufficiency prevents age-associated arterial pressure elevation and increases half-life in mice. Biochim Biophys Acta Mol Basis Dis 2016; 1863:113-120. [PMID: 27771508 DOI: 10.1016/j.bbadis.2016.10.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/22/2016] [Accepted: 10/18/2016] [Indexed: 02/07/2023]
Abstract
Catecholamines are essential for the maintenance of physiological homeostasis under basal and stress conditions. We aim to determine the impact of deletion of a single allele of the tyrosine hydroxylase (Th) gene might have on aging arterial pressure and life-span. We found that Th haploinsufficiency prevents age-associated increase of arterial pressure (AP) in mature adult mice, and it results in the extension of the half-life of Th-heterozygous (TH-HET) mice respect to their wild-type (WT) littermates. Heart performance was similar in both genotypes. To further investigate the lack of increase in AP with age in TH-HET mice, we measured the AP response to intra-peritoneal administration of substances involved in AP regulation. The response to acetylcholine and the basal sympathetic tone were similar in both genotypes, while norepinephrine had a greater pressor effect in TH-HET mice, which correlated with altered adrenoreceptor expression in blood vessels and the heart. Furthermore, sympatho-adrenomedular response to stress was attenuated in TH-HET mice. Plasma catecholamine levels and urine glucose increased markedly in WT but not in TH-HET mice after stress. Our results showed that TH-HET mice are resistant to age-associated hypertension, present a reduction in the sympathetic response to stress and display an extended half-life.
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Affiliation(s)
- Luis Gamella-Pozuelo
- Renal and Cardiovascular Physiopathology Unit, Department of Physiology and Pharmacology, Universidad de Salamanca, Spain; Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain; Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
| | - María T Grande
- Renal and Cardiovascular Physiopathology Unit, Department of Physiology and Pharmacology, Universidad de Salamanca, Spain
| | | | - Cayetana Murillo-Gómez
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), ISCIII, Spain
| | - Flora De Pablo
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), ISCIII, Spain
| | - José M López-Novoa
- Renal and Cardiovascular Physiopathology Unit, Department of Physiology and Pharmacology, Universidad de Salamanca, Spain; Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain
| | - Catalina Hernández-Sánchez
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), ISCIII, Spain.
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32
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Abstract
Sympathetic nerve activity is involved in the pathogenesis of salt-sensitive hypertension. The central nervous system, which regulates sympathetic nerve activity and blood pressure, plays a pivotal role. Central sympathoexcitation is deeply involved in the pathogenesis of salt-sensitive hypertension, although the precise mechanisms have not been fully elucidated because of their complexity. The role of brain oxidative stress in sympathoexcitation has been suggested in some types of hypertensive animal models. We have shown that increased brain oxidative stress may elevate arterial pressure through central sympathoexcitation in salt-sensitive hypertension. Several other factors such as mineralocorticoid receptors, aldosterone, corticosterone, epithelial sodium channels, and angiotensin II also play important roles in central sympathetic activation, some of which can be associated with brain oxidative stress. Furthermore, brain paraventricular nucleus Gαi2-protein-mediated transduction has been recently reported as a candidate for the molecular mechanism countering the development of salt-sensitive hypertension.
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33
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Vokurková M, Rauchová H, Řezáčová L, Vaněčková I, Zicha J. ROS production is increased in the kidney but not in the brain of Dahl rats with salt hypertension elicited in adulthood. Physiol Res 2016; 64:303-12. [PMID: 26066975 DOI: 10.33549/physiolres.933054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Enhanced production of superoxide radicals by nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase in the brain and/or kidney of salt hypertensive Dahl rats has been proposed to participate in the pathogenesis of this form of experimental hypertension. Most information was obtained in young Dahl salt-sensitive (DS) rats subjected to high salt intake prior to sexual maturation. Therefore, the aim of our study was to investigate whether salt hypertension induced in adult DS rats is also accompanied with a more pronounced oxidative stress in the brain or kidney as compared to Dahl salt-resistant (DR) controls. NADPH oxidase activity as well as the content of thiobarbituric acid-reactive substances (TBARS) and conjugated dienes (oxidative index), which indicate a degree of lipid peroxidation, were evaluated in two brain regions (containing either hypothalamic paraventricular nucleus or rostral ventrolateral medulla) as well as in renal medulla and cortex. High salt intake induced hypertension in DS rats but did not modify blood pressure in DR rats. DS and DR rats did not differ in NADPH oxidase-dependent production of ROS, TBARS content or oxidative index in either part of the brain. In addition, high-salt diet did not change significantly any of these brain parameters. In contrast, the enhanced NADPH oxidase-mediated ROS production (without significant signs of increased lipid peroxidation) was detected in the renal medulla of salt hypertensive DS rats. Our findings suggest that there are no signs of enhanced oxidative stress in the brain of adult Dahl rats with salt hypertension induced in adulthood.
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Affiliation(s)
- M Vokurková
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
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Zanella RC, Melo MR, Furuya WI, Colombari E, Menani JV, Colombari DSA. Hydrogen peroxide centrally attenuates hyperosmolarity-induced thirst and natriuresis. Neurosci Lett 2016; 610:129-34. [DOI: 10.1016/j.neulet.2015.10.067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/14/2015] [Accepted: 10/27/2015] [Indexed: 11/25/2022]
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Angiotensin-(1–7) enhances the effects of angiotensin II on the cardiac sympathetic afferent reflex and sympathetic activity in rostral ventrolateral medulla in renovascular hypertensive rats. ACTA ACUST UNITED AC 2015; 9:865-77. [DOI: 10.1016/j.jash.2015.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 04/11/2015] [Accepted: 08/06/2015] [Indexed: 11/21/2022]
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Su Q, Liu JJ, Cui W, Shi XL, Guo J, Li HB, Huo CJ, Miao YW, Zhang M, Yang Q, Kang YM. Alpha lipoic acid supplementation attenuates reactive oxygen species in hypothalamic paraventricular nucleus and sympathoexcitation in high salt-induced hypertension. Toxicol Lett 2015; 241:152-8. [PMID: 26518973 DOI: 10.1016/j.toxlet.2015.10.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 10/06/2015] [Accepted: 10/21/2015] [Indexed: 12/21/2022]
Abstract
AIMS High salt-induced oxidative stress plays an important role in the development of hypertension. Alpha lipoic acid (ALA) is extensively recognized as having a powerful superoxide inhibitory property. In this study, we determined whether ALA supplementation attenuates oxidative stress in hypothalamic paraventricular nucleus (PVN), decreases the sympathetic activity and arterial pressure in high salt-induced hypertension by cross-talking with renin-angiotensin system (RAS) and pro-inflammatory cytokines (PICs). METHODS Male Wistar rats were administered a normal-salt diet (NS, 0.3% NaCl) or a high-salt diet (HS, 8.0% NaCl) for 8 weeks. These rats received ALA (60mg/kg) dissolved in vehicle (0.9% saline) or an equal voleme of vehicle, by gastric perfusion for 9 weeks. RESULTS High salt intake resulted in higher renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP). These rats also had higher levels of superoxide, gp91(phox), gp47(phox) (subunits of NAD(P)H oxidase), angiotensin-converting enzyme (ACE), angiotensin II type1 receptor (AT1-R), interleukin-1beta (IL-1β), interleukin-6 (IL-6), and lower levels of interleukin-10 (IL-10) and copper/zinc superoxide dismutase (Cu/Zn-SOD) than control animals. Treatment with ALA significantly attenuated the levels of superoxide, gp91(phox), gp47(phox), ACE, AT1-R, IL-1β and IL-6, increased the levels of IL-10 and Cu/Zn-SOD, and decreased MAP and RSNA compared with high-salt induced hypertensive rats. The mRNA expression of gp47(phox) and gp91(phox) are in accordance with their protein expression. CONCLUSION These findings suggest that supplementation of ALA obviously decreases the sympathetic activity and arterial pressure in high salt-induced hypertension by improving the superoxide inhibitory property, suppressing the activation of RAS and restoring the balance between pro- and anti-inflammatory cytokines in the PVN.
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Affiliation(s)
- Qing Su
- Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an 710061, China
| | - Jin-Jun Liu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Wei Cui
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Xiao-Lian Shi
- Department of Pharmacology, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Jing Guo
- Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an 710061, China
| | - Hong-Bao Li
- Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an 710061, China
| | - Chan-Juan Huo
- Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an 710061, China
| | - Yu-Wang Miao
- Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an 710061, China
| | - Meng Zhang
- Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an 710061, China
| | - Qing Yang
- Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an 710061, China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an 710061, China.
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Devarajan S, Yahiro E, Uehara Y, Habe S, Nishiyama A, Miura SI, Saku K, Urata H. Depressor effect of chymase inhibitor in mice with high salt-induced moderate hypertension. Am J Physiol Heart Circ Physiol 2015; 309:H1987-96. [PMID: 26432844 DOI: 10.1152/ajpheart.00721.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 10/02/2015] [Indexed: 12/24/2022]
Abstract
The aim of the present study was to determine whether long-term high salt intake in the drinking water induces hypertension in wild-type (WT) mice and whether a chymase inhibitor or other antihypertensive drugs could reverse the increase of blood pressure. Eight-week-old male WT mice were supplied with drinking water containing 2% salt for 12 wk (high-salt group) or high-salt drinking water plus an oral chymase inhibitor (TPC-806) at four different doses (25, 50, 75, or 100 mg/kg), captopril (75 mg/kg), losartan (100 mg/kg), hydrochlorothiazide (3 mg/kg), eplerenone (200 mg/kg), or amlodipine (6 mg/kg). Control groups were given normal water with or without the chymase inhibitor. Blood pressure and heart rate gradually showed a significant increase in the high-salt group, whereas a dose-dependent depressor effect of the chymase inhibitor was observed. There was also partial improvement of hypertension in the losartan- and eplerenone-treated groups but not in the captopril-, hydrochlorothiazide-, and amlodipine-treated groups. A high salt load significantly increased chymase-dependent ANG II-forming activity in the alimentary tract. In addition, the relative contribution of chymase to ANG II formation, but not actual average activity, showed a significant increase in skin and skeletal muscle, whereas angiotensin-converting enzyme-dependent ANG II-forming activity and its relative contribution were reduced by high salt intake. Plasma and urinary renin-angiotensin system components were significantly increased in the high-salt group but were significantly suppressed in the chymase inhibitor-treated group. In conclusion, 2% salt water drinking for 12 wk caused moderate hypertension and activated the renin-angiotensin system in WT mice. A chymase inhibitor suppressed both the elevation of blood pressure and heart rate, indicating a definite involvement of chymase in salt-sensitive hypertension.
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Affiliation(s)
- Sankar Devarajan
- Department of Cardiovascular Diseases, Fukuoka University Chikushi Hospital, Fukuoka, Japan
| | - Eiji Yahiro
- Department of Cardiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Yoshinari Uehara
- Department of Cardiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Shigehisa Habe
- Department of Parasitology, Fukuoka University School of Medicine, Fukuoka, Japan; and
| | - Akira Nishiyama
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Shin-ichiro Miura
- Department of Cardiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Keijiro Saku
- Department of Cardiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Hidenori Urata
- Department of Cardiovascular Diseases, Fukuoka University Chikushi Hospital, Fukuoka, Japan;
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Chronic estrogen exposure affects gene expression in the rostral ventrolateral medulla of young and aging rats: Possible role in hypertension. Brain Res 2015; 1627:134-42. [PMID: 26375620 DOI: 10.1016/j.brainres.2015.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 08/03/2015] [Accepted: 09/05/2015] [Indexed: 01/11/2023]
Abstract
BACKGROUND Chronic exposure to estradiol-17β (E2) in adult female rats increases mean arterial pressure by stimulating superoxide production in the rostral ventrolateral medulla (RVLM). However the mechanisms behind this phenomenon are unknown. We hypothesized that E2 exposure induces the gene expression of cytokines, chemokines and NADPH oxidase (Nox) in the RVLM that promotes superoxide production and aging would exacerbate this effect. METHODS Young adult (3-4 month old) and middle-aged (6-8 month old) female Sprague Dawley rats were sham-implanted (YS and MS respectively) or implanted s.c. with slow-release E2 pellets (20 ng of E2/day for 90 days; YE and ME respectively). Blood pressure (BP) was measured during the last 3 weeks of exposure in a separate set of rats. At the end of treatment, the animals were sacrificed and RVLM was isolated from the brainstem. PCR array and Quantitative RT-PCR were performed with the tissue to quantify genes associated with hypertension and superoxide production. Superoxide dismutase (SOD) activity was also measured in the RVLM from a different set of animals. RESULTS E2 exposure increased mean arterial pressure in both YE and ME animals. Inflammatory genes such as interleukin-1β, interleukin-6 and monocyte chemoattractant protein-1 were significantly up-regulated in the RVLM of ME treated female rats compared to YS rats, but not in YE rats. Endothelin-1 (ET-1) gene was up-regulated in the RVLM of both YE and ME rats that were exposed to E2. Furthermore, chronic E2 treatment increased the mRNA levels of Nox1 and Nox2 genes in the RVLM of YE but not ME animals. SOD activity was reduced in MA animals, compared to young animals. E2 treatment had no significant effect on SOD activity. CONCLUSION Chronic E2 exposure stimulates the expression of inflammatory genes in older animals and increases the expression of Nox subunits in the RVLM of younger animals. SOD activity was reduced in older animals. This suggests increased superoxide production in younger animals, but reduced superoxide elimination in older animals. On the other hand, E2 exposure stimulates ET-1 expression in both young and aging animals. These findings suggest that hypertension caused by chronic E2 exposure may involve different molecular mediators in young and aging animals, however ET-1 and superoxide could be common mediators for both age groups.
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LI PENG, GONG JUEXIAO, SUN WEI, ZHOU BIN, KONG XIANGQING. Hexamethonium attenuates sympathetic activity and blood pressure in spontaneously hypertensive rats. Mol Med Rep 2015; 12:7116-22. [DOI: 10.3892/mmr.2015.4315] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 07/29/2015] [Indexed: 11/05/2022] Open
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Huber MJ, Basu R, Cecchettini C, Cuadra AE, Chen QH, Shan Z. Activation of the (pro)renin receptor in the paraventricular nucleus increases sympathetic outflow in anesthetized rats. Am J Physiol Heart Circ Physiol 2015; 309:H880-7. [PMID: 26116710 DOI: 10.1152/ajpheart.00095.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 06/24/2015] [Indexed: 02/07/2023]
Abstract
Previous studies have indicated that hyperactivity of brain prorenin receptors (PRR) is implicated in neurogenic hypertension. However, the role of brain PRR in regulating arterial blood pressure (ABP) is not well understood. Here, we test the hypothesis that PRR activation in the hypothalamic paraventricular nucleus (PVN) contributes to increased sympathetic nerve activity (SNA). In anaesthetized adult Sprague-Dawley (SD) rats, bilateral PVN microinjection of human prorenin (2 pmol/side) significantly increased splanchnic SNA (SSNA; 71 ± 15%, n = 7). Preinjection of either prorenin handle region peptide, the PRR binding blocker (PRRB), or tiron (2 nmol/side), the scavenger of reactive oxygen species (ROS), significantly attenuated the increase in SSNA (PRRB: 32 ± 5% vs. control, n = 6; tiron: 8 ± 10% vs. control, n = 5; P < 0.05) evoked by prorenin injection. We further investigated the effects of PRR activation on ROS production as well as downstream gene expression using cultured hypothalamus neurons from newborn SD rats. Incubation of brain neurons with human prorenin (100 nM) dramatically enhanced ROS production and induced a time-dependent increase in mRNA levels of inducible nitric oxide synthase (iNOS), NAPDH oxidase 2 subunit cybb, and FOS-like antigen 1 (fosl1), a marker for neuronal activation and a component of transcription factor activator protein-1 (AP-1). The maximum mRNA increase in these genes occurred 6 h following incubation (iNOS: 201-fold; cybb: 2 -fold; Ffosl1: 11-fold). The increases in iNOS and cybb mRNA were not attenuated by the AT1 receptor antagonist losartan but abolished by the AP-1 blocker curcumin. Our results suggest that PVN PRR activation induces sympathoexcitation possibly through stimulation of an ANG II-independent, ROS-AP-1-iNOS signaling pathway.
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Affiliation(s)
- Michael J Huber
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan
| | - Rupsa Basu
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan
| | - Cassie Cecchettini
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan
| | - Adolfo E Cuadra
- Department of Biology, University of Massachusetts, Amherst, Massachusetts; and
| | - Qing-Hui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan; Biotech Research Center, Michigan Technological University, Houghton, Michigan
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan; Biotech Research Center, Michigan Technological University, Houghton, Michigan
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Superoxide Mediates Depressive Effects Induced by Hydrogen Sulfide in Rostral Ventrolateral Medulla of Spontaneously Hypertensive Rats. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:927686. [PMID: 26078823 PMCID: PMC4442288 DOI: 10.1155/2015/927686] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/04/2015] [Accepted: 01/04/2015] [Indexed: 12/02/2022]
Abstract
Hydrogen sulfide (H2S) plays a crucial role in the regulation of blood pressure and oxidative stress. In the present study, we tested the hypothesis that H2S exerts its cardiovascular effects by reducing oxidative stress via inhibition of NADPH oxidase activity in the rostral ventrolateral medulla (RVLM). We examined cell distributions of cystathionine-β-synthase (CBS) and effects of H2S on reactive oxygen species (ROS) and mean arterial blood pressure (MAP) in spontaneously hypertensive rats (SHRs). We found that CBS was expressed in neurons of the RVLM, and the expression was lower in SHRs than in Wistar-Kyoto rats. Microinjection of NaHS (H2S donor), S-adenosyl-l-methionine (SAM, a CBS agonist), or Apocynin (NADPH oxidase inhibitor) into the RVLM reduced the ROS level, NADPH oxidase activity, and MAP, whereas microinjection of hydroxylamine hydrochloride (HA, a CBS inhibitor) increased MAP. Furthermore, intracerebroventricular infusion of NaHS inhibited phosphorylation of p47phox, a key step of NADPH oxidase activation. Since decreasing ROS level in the RVLM reduces MAP and heart rate and increasing H2S reduces ROS production, we conclude that H2S exerts an antihypertensive effect via suppressing ROS production. H2S, as an antioxidant, may be a potential target for cardiovascular diseases.
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Nishimoto M, Fujita T. Renal mechanisms of salt-sensitive hypertension: contribution of two steroid receptor-associated pathways. Am J Physiol Renal Physiol 2015; 308:F377-87. [DOI: 10.1152/ajprenal.00477.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Although salt is a major environmental factor in the development of hypertension, the degree of salt sensitivity varies widely among individuals. The mechanisms responsible for this variation remain to be elucidated. Recent studies have revealed the involvement of two important signaling pathways in renal tubules that play key roles in electrolyte balance and the maintenance of normal blood pressure: the β2-adrenergic stimulant-glucocorticoid receptor (GR)-with-no-lysine kinase (WNK)4-Na+-Cl− cotransporter pathway, which is active in distal convoluted tubule (DCT)1, and the Ras-related C3 botulinum toxin substrate (Rac)1-mineralocorticoid receptor (MR) pathway, which is active in DCT2, connecting tubules, and collecting ducts. β2-Adrenergic stimulation due to increased renal sympathetic activity in obesity- and salt-induced hypertension suppresses histone deacetylase 8 activity via cAMP/PKA signaling, increasing the accessibility of GRs to the negative GR response element in the WNK4 promoter. This results in the suppression of WNK4 transcription followed by the activation of Na+-Cl− cotransporters in the DCT and elevated Na+ retention and blood pressure upon salt loading. Rac1 activates MRs, even in the absence of ligand binding, with this activity increased in the presence of ligand. In salt-sensitive animals, Rac1 activation due to salt loading activates MRs in DCT2, connecting tubules, and collecting ducts. Thus, GRs and MRs are independently involved in two pathways responsible for renal Na+ handling and salt-sensitive hypertension. These findings suggest novel therapeutic targets and may lead to the development of diagnostic tools to determine salt sensitivity in hypertensive patients.
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Affiliation(s)
- Mitsuhiro Nishimoto
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
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Uetake Y, Ikeda H, Irie R, Tejima K, Matsui H, Ogura S, Wang H, Mu S, Hirohama D, Ando K, Sawamura T, Yatomi Y, Fujita T, Shimosawa T. High-salt in addition to high-fat diet may enhance inflammation and fibrosis in liver steatosis induced by oxidative stress and dyslipidemia in mice. Lipids Health Dis 2015; 14:6. [PMID: 25888871 PMCID: PMC4337194 DOI: 10.1186/s12944-015-0002-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 01/21/2015] [Indexed: 12/22/2022] Open
Abstract
Background It is widely known that salt is an accelerating factor for the progression of metabolic syndrome and causes cardiovascular diseases, most likely due to its pro-oxidant properties. We hypothesized that excessive salt intake also facilitates the development of nonalcoholic steatohepatitis (NASH), which is frequently associated with metabolic syndrome. Methods We examined the exacerbating effect of high-salt diet on high-fat diet-induced liver injury in a susceptible model to oxidative stress, apoE knockout and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) transgenic mice. Results High-salt diet led to NASH in high-fat diet-fed LOX-1 transgenic/apoE knockout mice without affecting high-fat diet-induced dyslipidemia or hepatic triglyceride accumulation. Additionally, a high-salt and high-fat diet stimulated oxidative stress production and inflammatory reaction to a greater extent than did a high-fat diet in the liver of LOX-1 transgenic/apoE knockout mice. Conclusions We demonstrated that high-salt diet exacerbated NASH in high-fat diet-fed LOX-1 transgenic /apoE knockout mice and that this effect was associated with the stimulation of oxidative and inflammatory processes; this is the first study to suggest the important role of excessive salt intake in the development of NASH. Electronic supplementary material The online version of this article (doi:10.1186/s12944-015-0002-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuzaburo Uetake
- Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan. .,Office for Research Ethics Support, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
| | - Hitoshi Ikeda
- Clinical Laboratory, The University of Tokyo Hospital, Tokyo, Japan. .,Department of Gastroenterology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
| | - Rie Irie
- Department of Pathology, Kawasaki Municipal Hospital, Kawasaki, Japan.
| | - Kazuaki Tejima
- Department of Gastroenterology, Toshiba General Hospital, Tokyo, Japan.
| | - Hiromitsu Matsui
- Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
| | - Sayoko Ogura
- Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan. .,Division of Laboratory Medicine, Department of Pathology and Microbiology, Faculty of Medicine, Nihon University School of Medicine, Tokyo, Japan.
| | - Hong Wang
- Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
| | - ShengYu Mu
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.
| | - Daigoro Hirohama
- Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
| | - Katsuyuki Ando
- Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
| | - Tatsuya Sawamura
- Department of Vascular Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan. .,Department of Physiology, Shinshu University School of Medicine, Nagano, Japan.
| | - Yutaka Yatomi
- Clinical Laboratory, The University of Tokyo Hospital, Tokyo, Japan.
| | - Toshiro Fujita
- Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan. .,Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.
| | - Tatsuo Shimosawa
- Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan. .,Clinical Laboratory, The University of Tokyo Hospital, Tokyo, Japan.
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Cowley AW, Abe M, Mori T, O'Connor PM, Ohsaki Y, Zheleznova NN. Reactive oxygen species as important determinants of medullary flow, sodium excretion, and hypertension. Am J Physiol Renal Physiol 2014; 308:F179-97. [PMID: 25354941 DOI: 10.1152/ajprenal.00455.2014] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The physiological evidence linking the production of superoxide, hydrogen peroxide, and nitric oxide in the renal medullary thick ascending limb of Henle (mTAL) to regulation of medullary blood flow, sodium homeostasis, and long-term control of blood pressure is summarized in this review. Data obtained largely from rats indicate that experimentally induced elevations of either superoxide or hydrogen peroxide in the renal medulla result in reduction of medullary blood flow, enhanced Na(+) reabsorption, and hypertension. A shift in the redox balance between nitric oxide and reactive oxygen species (ROS) is found to occur naturally in the Dahl salt-sensitive (SS) rat model, where selective reduction of ROS production in the renal medulla reduces salt-induced hypertension. Excess medullary production of ROS in SS rats emanates from the medullary thick ascending limbs of Henle [from both the mitochondria and membrane NAD(P)H oxidases] in response to increased delivery and reabsorption of excess sodium and water. There is evidence that ROS and perhaps other mediators such as ATP diffuse from the mTAL to surrounding vasa recta capillaries, resulting in medullary ischemia, which thereby contributes to hypertension.
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Affiliation(s)
- Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Michiaki Abe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Takefumi Mori
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Paul M O'Connor
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Yusuke Ohsaki
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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Hamza SM, Dyck JRB. Systemic and renal oxidative stress in the pathogenesis of hypertension: modulation of long-term control of arterial blood pressure by resveratrol. Front Physiol 2014; 5:292. [PMID: 25140155 PMCID: PMC4122172 DOI: 10.3389/fphys.2014.00292] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/19/2014] [Indexed: 12/12/2022] Open
Abstract
Hypertension affects over 25% of the global population and is associated with grave and often fatal complications that affect many organ systems. Although great advancements have been made in the clinical assessment and treatment of hypertension, the cause of hypertension in over 90% of these patients is unknown, which hampers the development of targeted and more effective treatment. The etiology of hypertension involves multiple pathological processes and organ systems, however one unifying feature of all of these contributing factors is oxidative stress. Once the body's natural anti-oxidant defense mechanisms are overwhelmed, reactive oxygen species (ROS) begin to accumulate in the tissues. ROS play important roles in normal regulation of many physiological processes, however in excess they are detrimental and cause widespread cell and tissue damage as well as derangements in many physiological processes. Thus, control of oxidative stress has become an attractive target for pharmacotherapy to prevent and manage hypertension. Resveratrol (trans-3,5,4'-Trihydroxystilbene) is a naturally occurring polyphenol which has anti-oxidant effects in vivo. Many studies have shown anti-hypertensive effects of resveratrol in different pre-clinical models of hypertension, via a multitude of mechanisms that include its function as an anti-oxidant. However, results have been mixed and in some cases resveratrol has no effect on blood pressure. This may be due to the heavy emphasis on peripheral vasodilator effects of resveratrol and virtually no investigation of its potential renal effects. This is particularly troubling in the arena of hypertension, where it is well known and accepted that the kidney plays an essential role in the long term regulation of arterial pressure and a vital role in the initiation, development and maintenance of chronic hypertension. It is thus the focus of this review to discuss the potential of resveratrol as an anti-hypertensive treatment via amelioration of oxidative stress within the framework of the fundamental physiological principles of long term regulation of arterial blood pressure.
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Affiliation(s)
- Shereen M. Hamza
- Department of Pediatrics, Cardiovascular Research Centre, University of AlbertaEdmonton, AB, Canada
| | - Jason R. B. Dyck
- Department of Pediatrics, Cardiovascular Research Centre, University of AlbertaEdmonton, AB, Canada
- Department of Pharmacology, Cardiovascular Research Centre, University of AlbertaEdmonton, AB, Canada
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Chan EC, Dusting GJ, Liu GS, Jiang F. Redox mechanisms of the beneficial effects of heme oxygenase in hypertension. J Hypertens 2014; 32:1379-86; discussion 1387. [DOI: 10.1097/hjh.0000000000000179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Head GA, Andrianopoulos N, McGrath BP, Martin CA, Carrington MJ, Lukoshkova EV, Davern PJ, Jennings GL, Reid CM. Predictors of mean arterial pressure morning rate of rise and power function in subjects undergoing ambulatory blood pressure recording. PLoS One 2014; 9:e93186. [PMID: 24667944 PMCID: PMC3965554 DOI: 10.1371/journal.pone.0093186] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Accepted: 03/03/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND We determined clinical predictors of the rate of rise (RoR) in blood pressure in the morning as well as a novel measure of the power of the BP surge (BP(power)) derived from ambulatory blood pressure recordings. METHODS BP(power) and RoR were calculated from 409 ambulatory blood pressure (ABP) recordings from subjects attending a cardiovascular risk clinic. Anthropometric data, blood biochemistry, and history were recorded. The 409 subjects were 20-82 years old (average 57, SD = 13), 46% male, 9% with hypertension but not on medication and 34% on antihypertensive medication. RESULTS Average RoR was 11.1 mmHg/hour (SD = 8) and BP(power) was 273 mmHg(2)/hour (SD = 235). Only cholesterol, low density lipoprotein and body mass index (BMI) were associated with higher BP(power) and RoR (P<0.05) from 25 variables assessed. BP(power) was lower in those taking beta-blockers or diuretics. Multivariate analysis identified that only BMI was associated with RoR (4.2% increase/unit BMI, P = 0.020) while cholesterol was the only remaining associated variable with BP(power) (17.5% increase/mmol/L cholesterol, P = 0.047). A follow up of 213 subjects with repeated ABP after an average 1.8 years identified that baseline cholesterol was the only predictor for an increasing RoR and BP(power) (P<0.05). 37 patients who commenced statin subsequently had lower BP(power) whereas 90 age and weight matched controls had similar BP(power) on follow-up. CONCLUSIONS Cholesterol is an independent predictor of a greater and more rapid rise in morning BP as well as of further increases over several years. Reduction of cholesterol with statin therapy is very effective in reducing the morning blood pressure surge.
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Affiliation(s)
- Geoffrey A. Head
- Baker IDI Heart and Diabetes Institute, Melbourne and Department of Cardiovascular Medicine, Alfred Hospital, Melbourne, Australia
- * E-mail:
| | - Nick Andrianopoulos
- NHMRC Centre for Clinical Research Excellence in Therapeutics, Monash University, Melbourne, Australia
| | - Barry P. McGrath
- Monash Health Dandenong Australia and Monash University, Melbourne, Australia
| | - Catherine A. Martin
- Monash Health Dandenong Australia and Monash University, Melbourne, Australia
- Australian Catholic University, Fitzroy, Australia
| | - Melinda J. Carrington
- Baker IDI Heart and Diabetes Institute, Melbourne and Department of Cardiovascular Medicine, Alfred Hospital, Melbourne, Australia
| | | | - Pamela J. Davern
- Baker IDI Heart and Diabetes Institute, Melbourne and Department of Cardiovascular Medicine, Alfred Hospital, Melbourne, Australia
| | - Garry L. Jennings
- Baker IDI Heart and Diabetes Institute, Melbourne and Department of Cardiovascular Medicine, Alfred Hospital, Melbourne, Australia
| | - Christopher M. Reid
- NHMRC Centre for Clinical Research Excellence in Therapeutics, Monash University, Melbourne, Australia
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Abstract
The role of sympathetic nerve activity in hypertension is currently receiving increased attention, because catheter-based renal denervation was recently shown to reduce blood pressure safely in patients with treatment-resistant hypertension. The central nervous system, which regulates sympathetic nerve activity and blood pressure, is pivotal. Central sympathoexcitation has been shown to be deeply involved in the pathogenesis of salt-sensitive hypertension, although its precise mechanisms have not yet been fully elucidated due to their complexity. Recently, a role for brain oxidative stress in sympathoexcitation has been suggested in some hypertensive animal models. We have demonstrated that increased brain oxidative stress may elevate arterial pressure through central sympathoexcitation in salt-sensitive hypertension. Several factors other than oxidative stress have also been shown to play important roles in central sympathetic activation. In the future, strategies may be developed to elicit a sympathetic inhibition by modulating these factors to prevent and manage salt-sensitive hypertension.
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Affiliation(s)
- Megumi Fujita
- Department of Nephrology and Endocrinology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
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Hubens LEG, Verloop WL, Joles JA, Blankestijn PJ, Voskuil M. Ischemia and reactive oxygen species in sympathetic hyperactivity states: a vicious cycle that can be interrupted by renal denervation? Curr Hypertens Rep 2014; 15:313-20. [PMID: 23754326 DOI: 10.1007/s11906-013-0367-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Renal denervation has developed as a new treatment strategy for patients suffering from resistant hypertension. The success of this therapy is due to the fact that sympathetic hyperactivity is involved in the pathogenesis of elevated blood pressure. However, not only the sympathetic nervous system (SNS), but also the renin angiotensin system (RAS) is known to be involved in hypertension. In addition, RAS is involved in other sympathetic hyperactivity states, such as heart failure, chronic kidney disease, insulin resistance and obstructive sleep apnea. Moreover, renal denervation has a beneficial effect on patients suffering from these disease states. Recent research suggested that the production of reactive oxygen species (ROS) is elevated in sympathetic hyperactivity states, and that ROS are able to activate the SNS and local tissue renin angiotensin system. Therefore, this review discusses the possibility of ROS as a common trigger of SNS and RAS activity in sympathetic hyperactivity states, and the effect of renal denervation on this ROS production.
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Affiliation(s)
- Lisette E G Hubens
- Division of Heart and Lungs, Department of Cardiology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
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Revealing the role of the autonomic nervous system in the development and maintenance of Goldblatt hypertension in rats. Auton Neurosci 2014; 183:23-9. [PMID: 24560525 PMCID: PMC4079011 DOI: 10.1016/j.autneu.2014.02.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 01/27/2014] [Accepted: 02/01/2014] [Indexed: 11/30/2022]
Abstract
Despite extensive use of the renovascular/Goldblatt model of hypertension—2K-1C, and the use of renal denervation to treat drug resistant hypertensive patients, autonomic mechanisms that underpin the maintenance of this hypertension are important yet remain unclear. Our aim was to analyse cardiovascular autonomic function by power spectral density analysis of both arterial pressure and pulse interval measured continuously by radio telemetry for 6 weeks after renal artery clipping. Mean arterial pressure increased from 106 ± 5 to 185 ± 2 mm Hg during 5 weeks post clipping when it stabilized. A tachycardia developed during the 4th week, which plateaued between weeks 5 and 6. The gain of the cardiac vagal baroreflex decreased immediately after clipping and continued to do so until the 5th week when it plateaued (from − 2.4 ± 0.09 to − 0.8 ± 0.04 bpm/mm Hg; P < 0.05). A similar time course of changes in the high frequency power spectral density of the pulse interval was observed (decrease from 13.4 ± 0.6 to 8.3 ± 0.01 ms2; P < 0.05). There was an increase in both the very low frequency and low frequency components of systolic blood pressure that occurred 3 and 4 weeks after clipping, respectively. Thus, we show for the first time the temporal profile of autonomic mechanisms underpinning the initiation, development and maintenance of renovascular hypertension including: an immediate depression of cardiac baroreflex gain followed by a delayed cardiac sympathetic predominance; elevated sympathetic vasomotor drive occurring after the initiation of the hypertension but coinciding during its mid-development and maintenance.
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