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Baggeroer CE, Cambronero FE, Savan NA, Jefferson AL, Santisteban MM. Basic Mechanisms of Brain Injury and Cognitive Decline in Hypertension. Hypertension 2024; 81:34-44. [PMID: 37732479 PMCID: PMC10840624 DOI: 10.1161/hypertensionaha.123.19939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Dementia affects almost 50 million adults worldwide, and remains a major cause of death and disability. Hypertension is a leading risk factor for dementia, including Alzheimer disease and Alzheimer disease-related dementias. Although this association is well-established, the mechanisms underlying hypertension-induced cognitive decline remain poorly understood. By exploring the mechanisms mediating the detrimental effects of hypertension on the brain, studies have aimed to provide therapeutic insights and strategies on how to protect the brain from the effects of blood pressure elevation. In this review, we focus on the basic mechanisms contributing to the cerebrovascular adaptions to elevated blood pressure and hypertension-induced microvascular injury. We also assess the cellular mechanisms of neurovascular unit dysfunction, focusing on the premise that cognitive impairment ensues when the dynamic metabolic demands of neurons are not met due to neurovascular uncoupling, and summarize cognitive deficits across various rodent models of hypertension as a resource for investigators. Despite significant advances in antihypertensive therapy, hypertension remains a critical risk factor for cognitive decline, and several questions remain about the development and progression of hypertension-induced cognitive impairment.
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Affiliation(s)
- Caroline E. Baggeroer
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN
| | - Francis E. Cambronero
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN
| | - N. Anna Savan
- Medical Scientist Training Program, Yale University, New Haven, CT
| | - Angela L. Jefferson
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Monica M. Santisteban
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
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2
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Mladenov M, Lubomirov L, Grisk O, Avtanski D, Mitrokhin V, Sazdova I, Keremidarska-Markova M, Danailova Y, Nikolaev G, Konakchieva R, Gagov H. Oxidative Stress, Reductive Stress and Antioxidants in Vascular Pathogenesis and Aging. Antioxidants (Basel) 2023; 12:antiox12051126. [PMID: 37237992 DOI: 10.3390/antiox12051126] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/22/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
This review is focused on the mechanisms that regulate health, disease and aging redox status, the signal pathways that counteract oxidative and reductive stress, the role of food components and additives with antioxidant properties (curcumin, polyphenols, vitamins, carotenoids, flavonoids, etc.), and the role of the hormones irisin and melatonin in the redox homeostasis of animal and human cells. The correlations between the deviation from optimal redox conditions and inflammation, allergic, aging and autoimmune responses are discussed. Special attention is given to the vascular system, kidney, liver and brain oxidative stress processes. The role of hydrogen peroxide as an intracellular and paracrine signal molecule is also reviewed. The cyanotoxins β-N-methylamino-l-alanine (BMAA), cylindrospermopsin, microcystins and nodularins are introduced as potentially dangerous food and environment pro-oxidants.
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Affiliation(s)
- Mitko Mladenov
- Faculty of Natural Sciences and Mathematics, Institute of Biology, "Ss. Cyril and Methodius" University, P.O. Box 162, 1000 Skopje, North Macedonia
| | - Lubomir Lubomirov
- Institute of Physiology, Brandenburg Medical School Theodor Fontane, 16816 Neuruppin, Germany
| | - Olaf Grisk
- Institute of Physiology, Brandenburg Medical School Theodor Fontane, 16816 Neuruppin, Germany
| | - Dimiter Avtanski
- Friedman Diabetes Institute, Lenox Hill Hospital, Northwell Health, 110 E 59th Street, New York, NY 10003, USA
| | - Vadim Mitrokhin
- Department of Physiology, Pirogov Russian National Research Medical University, 1 Ostrovityanova Street, 117997 Moscow, Russia
| | - Iliyana Sazdova
- Department of Animal and Human Physiology, Faculty of Biology, Sofia University "St. Kliment Ohridski", 8 Dragan Tzankov Blvd., 1164 Sofia, Bulgaria
| | - Milena Keremidarska-Markova
- Department of Animal and Human Physiology, Faculty of Biology, Sofia University "St. Kliment Ohridski", 8 Dragan Tzankov Blvd., 1164 Sofia, Bulgaria
| | - Yana Danailova
- Department of Animal and Human Physiology, Faculty of Biology, Sofia University "St. Kliment Ohridski", 8 Dragan Tzankov Blvd., 1164 Sofia, Bulgaria
| | - Georgi Nikolaev
- Department of Cell and Developmental Biology, Faculty of Biology, Sofia University "St. Kliment Ohridski", 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria
| | - Rossitza Konakchieva
- Department of Cell and Developmental Biology, Faculty of Biology, Sofia University "St. Kliment Ohridski", 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria
| | - Hristo Gagov
- Department of Animal and Human Physiology, Faculty of Biology, Sofia University "St. Kliment Ohridski", 8 Dragan Tzankov Blvd., 1164 Sofia, Bulgaria
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Abstract
Hypertension affects a significant proportion of the adult and aging population and represents an important risk factor for vascular cognitive impairment and late-life dementia. Chronic high blood pressure continuously challenges the structural and functional integrity of the cerebral vasculature, leading to microvascular rarefaction and dysfunction, and neurovascular uncoupling that typically impairs cerebral blood supply. Hypertension disrupts blood-brain barrier integrity, promotes neuroinflammation, and may contribute to amyloid deposition and Alzheimer pathology. The mechanisms underlying these harmful effects are still a focus of investigation, but studies in animal models have provided significant molecular and cellular mechanistic insights. Remaining questions relate to whether adequate treatment of hypertension may prevent deterioration of cognitive function, the threshold for blood pressure treatment, and the most effective antihypertensive drugs. Recent advances in neurovascular biology, advanced brain imaging, and detection of subtle behavioral phenotypes have begun to provide insights into these critical issues. Importantly, a parallel analysis of these parameters in animal models and humans is feasible, making it possible to foster translational advancements. In this review, we provide a critical evaluation of the evidence available in experimental models and humans to examine the progress made and identify remaining gaps in knowledge.
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Affiliation(s)
| | - Costantino Iadecola
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY
| | - Daniela Carnevale
- Department of Molecular Medicine, “Sapienza” University of Rome, Italy
- Research Unit of Neuro and Cardiovascular Pathophysiology, IRCCS Neuromed, Pozzilli, Italy
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4
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Sabharwal R, Chapleau MW, Gerhold TD, Baumbach GL, Faraci FM. Plasticity of cerebral microvascular structure and mechanics during hypertension and following recovery of arterial pressure. Am J Physiol Heart Circ Physiol 2022; 323:H1108-H1117. [PMID: 36269650 PMCID: PMC9678426 DOI: 10.1152/ajpheart.00292.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 09/28/2022] [Accepted: 10/13/2022] [Indexed: 12/14/2022]
Abstract
Changes in vascular structure contribute to vascular events and loss of brain health. We examined changes in cerebral arterioles at the onset of hypertension and the hypothesis that alterations during hypertension would recover with the return of mean arterial pressure (MAP) to normal. MAP was measured with radiotelemetry in awake male C57BL/6J mice at baseline and during infusion of vehicle or angiotensin II (ANG II, 1.4 mg/kg/day using osmotic pumps) for 28 days, followed by a 28-day recovery. With ANG II treatment, MAP increased through day 28. On day 30, MAP began to recover, reaching levels not different from vehicle on day 37. We measured intravascular pressure, diameter, wall thickness (WT), wall:lumen ratio (W:L), cross-sectional area (CSA), and slope of the tangential elastic modulus (ET) in maximally dilated arterioles. Variables were similar in both groups at day 1, with no significant change with vehicle treatment. With ANG II treatment, CSA, WT, and W:L increased on days 7-28. Internal and external diameter was reduced at 14 and 28 days. ET versus wall stress was reduced on days 7-28. During recovery, the diameter remained at days 14 and 28 values, whereas other variables returned partly or completely to normal. Thus, CSA, WT, W:L, and ET versus wall stress changed rapidly during hypertension and recovered with MAP. In contrast, inward remodeling developed slowly and did not recover. This lack of recovery has mechanistic implications for the long-term impact of hypertension on vascular determinants of brain health.NEW & NOTEWORTHY Changes in vascular structure contribute to vascular events and loss of brain health. We examined the inherent structural plasticity of cerebral arterioles during and after a period of hypertension. Arteriolar wall thickness, diameter, wall-to-lumen ratio, and biological stiffness changed rapidly during hypertension and recovered with blood pressure. In contrast, inward remodeling developed slowly and did not recover. This lack of recovery of arteriolar diameter has implications for the long-term impact of hypertension on vascular determinants of brain health.
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Affiliation(s)
- Rasna Sabharwal
- Department of Internal Medicine, Carver College of Medicine, Francois M. Abboud Cardiovascular Center, University of Iowa, Iowa City, Iowa
- Department of Neuroscience and Pharmacology, Carver College of Medicine, Francois M. Abboud Cardiovascular Center, University of Iowa, Iowa City, Iowa
| | - Mark W Chapleau
- Department of Internal Medicine, Carver College of Medicine, Francois M. Abboud Cardiovascular Center, University of Iowa, Iowa City, Iowa
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, Francois M. Abboud Cardiovascular Center, University of Iowa, Iowa City, Iowa
| | - Thomas D Gerhold
- Department of Internal Medicine, Carver College of Medicine, Francois M. Abboud Cardiovascular Center, University of Iowa, Iowa City, Iowa
| | - Gary L Baumbach
- Department of Pathology, Carver College of Medicine, Francois M. Abboud Cardiovascular Center, University of Iowa, Iowa City, Iowa
| | - Frank M Faraci
- Department of Internal Medicine, Carver College of Medicine, Francois M. Abboud Cardiovascular Center, University of Iowa, Iowa City, Iowa
- Department of Neuroscience and Pharmacology, Carver College of Medicine, Francois M. Abboud Cardiovascular Center, University of Iowa, Iowa City, Iowa
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5
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Baumeister J, Maié T, Chatain N, Gan L, Weinbergerova B, de Toledo MAS, Eschweiler J, Maurer A, Mayer J, Kubesova B, Racil Z, Schuppert A, Costa I, Koschmieder S, Brümmendorf TH, Gezer D. Early and late stage MPN patients show distinct gene expression profiles in CD34 + cells. Ann Hematol 2021; 100:2943-2956. [PMID: 34390367 PMCID: PMC8592960 DOI: 10.1007/s00277-021-04615-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 07/11/2021] [Indexed: 12/12/2022]
Abstract
Myeloproliferative neoplasms (MPN), comprising essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF), are hematological disorders of the myeloid lineage characterized by hyperproliferation of mature blood cells. The prediction of the clinical course and progression remains difficult and new therapeutic modalities are required. We conducted a CD34+ gene expression study to identify signatures and potential biomarkers in the different MPN subtypes with the aim to improve treatment and prevent the transformation from the rather benign chronic state to a more malignant aggressive state. We report here on a systematic gene expression analysis (GEA) of CD34+ peripheral blood or bone marrow cells derived from 30 patients with MPN including all subtypes (ET (n = 6), PV (n = 11), PMF (n = 9), secondary MF (SMF; post-ET-/post-PV-MF; n = 4)) and six healthy donors. GEA revealed a variety of differentially regulated genes in the different MPN subtypes vs. controls, with a higher number in PMF/SMF (200/272 genes) than in ET/PV (132/121). PROGENγ analysis revealed significant induction of TNFα/NF-κB signaling (particularly in SMF) and reduction of estrogen signaling (PMF and SMF). Consistently, inflammatory GO terms were enriched in PMF/SMF, whereas RNA splicing–associated biological processes were downregulated in PMF. Differentially regulated genes that might be utilized as diagnostic/prognostic markers were identified, such as AREG, CYBB, DNTT, TIMD4, VCAM1, and S100 family members (S100A4/8/9/10/12). Additionally, 98 genes (including CLEC1B, CMTM5, CXCL8, DACH1, and RADX) were deregulated solely in SMF and may be used to predict progression from early to late stage MPN.
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Affiliation(s)
- Julian Baumeister
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany
| | - Tiago Maié
- Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany.,Institute for Computational Genomics, RWTH Aachen University, Aachen, Germany
| | - Nicolas Chatain
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany
| | - Lin Gan
- IZKF Genomics Core Facility, RWTH Aachen University Medical School, Aachen, Germany
| | - Barbora Weinbergerova
- Department of Internal Medicine, Hematology and Oncology, Masaryk University and University Hospital Brno, Brno, Czech Republic
| | - Marcelo A S de Toledo
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany
| | - Jörg Eschweiler
- Department of Orthopedic Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Angela Maurer
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany
| | - Jiri Mayer
- Department of Internal Medicine, Hematology and Oncology, Masaryk University and University Hospital Brno, Brno, Czech Republic
| | - Blanka Kubesova
- Department of Internal Medicine, Hematology and Oncology, Masaryk University and University Hospital Brno, Brno, Czech Republic
| | - Zdenek Racil
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic
| | - Andreas Schuppert
- Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany.,Joint Research Center for Computational Biomedicine, RWTH Aachen, Aachen, Germany
| | - Ivan Costa
- Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany.,Institute for Computational Genomics, RWTH Aachen University, Aachen, Germany
| | - Steffen Koschmieder
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany
| | - Tim H Brümmendorf
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany
| | - Deniz Gezer
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany. .,Center for Integrated Oncology, Aachen Bonn Cologne Duesseldorf (CIO ABCD), Aachen, Germany.
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6
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Elkahloun AG, Saavedra JM. Candesartan could ameliorate the COVID-19 cytokine storm. Biomed Pharmacother 2020; 131:110653. [PMID: 32942152 PMCID: PMC7439834 DOI: 10.1016/j.biopha.2020.110653] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Angiotensin receptor blockers (ARBs) reducing inflammation and protecting lung and brain function, could be of therapeutic efficacy in COVID-19 patients. METHODS Using GSEA, we compared our previous transcriptome analysis of neurons injured by glutamate and treated with the ARB Candesartan (GSE67036) with transcriptional signatures from SARS-CoV-2 infected primary human bronchial epithelial cells (NHBE) and lung postmortem (GSE147507), PBMC and BALF samples (CRA002390) from COVID-19 patients. RESULTS Hundreds of genes upregulated in SARS-CoV-2/COVID-19 transcriptomes were similarly upregulated by glutamate and normalized by Candesartan. Gene Ontology analysis revealed expression profiles with greatest significance and enrichment, including proinflammatory cytokine and chemokine activity, the NF-kappa B complex, alterations in innate and adaptive immunity, with many genes participating in the COVID-19 cytokine storm. CONCLUSIONS There are similar injury mechanisms in SARS-CoV-2 infection and neuronal injury, equally reduced by ARB treatment. This supports the hypothesis of a therapeutic role for ARBs, ameliorating the COVID-19 cytokine storm.
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Affiliation(s)
- Abdel G Elkahloun
- Comparative Genomics and Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Juan M Saavedra
- Department of Pharmacology and Physiology, Georgetown University Medical Center, SE402 Med/Dent, 3900 Reservoir Road, Washington, DC 20057, USA.
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7
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Cosarderelioglu C, Nidadavolu LS, George CJ, Oh ES, Bennett DA, Walston JD, Abadir PM. Brain Renin-Angiotensin System at the Intersect of Physical and Cognitive Frailty. Front Neurosci 2020; 14:586314. [PMID: 33117127 PMCID: PMC7561440 DOI: 10.3389/fnins.2020.586314] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 08/25/2020] [Indexed: 12/15/2022] Open
Abstract
The renin–angiotensin system (RAS) was initially considered to be part of the endocrine system regulating water and electrolyte balance, systemic vascular resistance, blood pressure, and cardiovascular homeostasis. It was later discovered that intracrine and local forms of RAS exist in the brain apart from the endocrine RAS. This brain-specific RAS plays essential roles in brain homeostasis by acting mainly through four angiotensin receptor subtypes; AT1R, AT2R, MasR, and AT4R. These receptors have opposing effects; AT1R promotes vasoconstriction, proliferation, inflammation, and oxidative stress while AT2R and MasR counteract the effects of AT1R. AT4R is critical for dopamine and acetylcholine release and mediates learning and memory consolidation. Consequently, aging-associated dysregulation of the angiotensin receptor subtypes may lead to adverse clinical outcomes such as Alzheimer’s disease and frailty via excessive oxidative stress, neuroinflammation, endothelial dysfunction, microglial polarization, and alterations in neurotransmitter secretion. In this article, we review the brain RAS from this standpoint. After discussing the functions of individual brain RAS components and their intracellular and intracranial locations, we focus on the relationships among brain RAS, aging, frailty, and specific neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and vascular cognitive impairment, through oxidative stress, neuroinflammation, and vascular dysfunction. Finally, we discuss the effects of RAS-modulating drugs on the brain RAS and their use in novel treatment approaches.
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Affiliation(s)
- Caglar Cosarderelioglu
- Division of Geriatrics, Department of Internal Medicine, Ankara University School of Medicine, Ankara, Turkey.,Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Lolita S Nidadavolu
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Claudene J George
- Division of Geriatrics, Department of Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, United States
| | - Esther S Oh
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, United States
| | - Jeremy D Walston
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Peter M Abadir
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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8
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Forrester SJ, Booz GW, Sigmund CD, Coffman TM, Kawai T, Rizzo V, Scalia R, Eguchi S. Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology. Physiol Rev 2018; 98:1627-1738. [PMID: 29873596 DOI: 10.1152/physrev.00038.2017] [Citation(s) in RCA: 621] [Impact Index Per Article: 103.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT1R) is believed to mediate most functions of ANG II in the system. AT1R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT1R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT1R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.
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Affiliation(s)
- Steven J Forrester
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - George W Booz
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Curt D Sigmund
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Thomas M Coffman
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Tatsuo Kawai
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Victor Rizzo
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Rosario Scalia
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
| | - Satoru Eguchi
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University , Philadelphia, Pennsylvania ; Department of Pharmacology and Toxicology, School of Medicine, University of Mississippi Medical Center , Jackson, Mississippi ; Department of Pharmacology, Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa ; and Duke-NUS, Singapore and Department of Medicine, Duke University Medical Center , Durham, North Carolina
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9
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Cipolla MJ, Liebeskind DS, Chan SL. The importance of comorbidities in ischemic stroke: Impact of hypertension on the cerebral circulation. J Cereb Blood Flow Metab 2018; 38:2129-2149. [PMID: 30198826 PMCID: PMC6282213 DOI: 10.1177/0271678x18800589] [Citation(s) in RCA: 185] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Comorbidities are a hallmark of stroke that both increase the incidence of stroke and worsen outcome. Hypertension is prevalent in the stroke population and the most important modifiable risk factor for stroke. Hypertensive disorders promote stroke through increased shear stress, endothelial dysfunction, and large artery stiffness that transmits pulsatile flow to the cerebral microcirculation. Hypertension also promotes cerebral small vessel disease through several mechanisms, including hypoperfusion, diminished autoregulatory capacity and localized increase in blood-brain barrier permeability. Preeclampsia, a hypertensive disorder of pregnancy, also increases the risk of stroke 4-5-fold compared to normal pregnancy that predisposes women to early-onset cognitive impairment. In this review, we highlight how comorbidities and concomitant disorders are not only risk factors for ischemic stroke, but alter the response to acute ischemia. We focus on hypertension as a comorbidity and its effects on the cerebral circulation that alters the pathophysiology of ischemic stroke and should be considered in guiding future therapeutic strategies.
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Affiliation(s)
- Marilyn J Cipolla
- 1 Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - David S Liebeskind
- 2 Neurovascular Imaging Research Core and Stroke Center, Department of Neurology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Siu-Lung Chan
- 1 Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
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10
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Sheehe JL, Bonev AD, Schmoker AM, Ballif BA, Nelson MT, Moon TM, Dostmann WR. Oxidation of cysteine 117 stimulates constitutive activation of the type Iα cGMP-dependent protein kinase. J Biol Chem 2018; 293:16791-16802. [PMID: 30206122 DOI: 10.1074/jbc.ra118.004363] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 09/04/2018] [Indexed: 12/22/2022] Open
Abstract
The type I cGMP-dependent protein kinase (PKG I) is an essential regulator of vascular tone. It has been demonstrated that the type Iα isoform can be constitutively activated by oxidizing conditions. However, the amino acid residues implicated in this phenomenon are not fully elucidated. To investigate the molecular basis for this mechanism, we studied the effects of oxidation using recombinant WT, truncated, and mutant constructs of PKG I. Using an in vitro assay, we observed that oxidation with hydrogen peroxide (H2O2) resulted in constitutive, cGMP-independent activation of PKG Iα. PKG Iα C42S and a truncation construct that does not contain Cys-42 (Δ53) were both constitutively activated by H2O2 In contrast, oxidation of PKG Iα C117S maintained its cGMP-dependent activation characteristics, although oxidized PKG Iα C195S did not. To corroborate these results, we also tested the effects of our constructs on the PKG Iα-specific substrate, the large conductance potassium channel (KCa 1.1). Application of WT PKG Iα activated by either cGMP or H2O2 increased the open probabilities of the channel. Neither cGMP nor H2O2 activation of PKG Iα C42S significantly increased channel open probabilities. Moreover, cGMP-stimulated PKG Iα C117S increased KCa 1.1 activity, but this effect was not observed under oxidizing conditions. Finally, we observed that PKG Iα C42S caused channel flickers, indicating dramatically altered KCa 1.1 channel characteristics compared with channels exposed to WT PKG Iα. Cumulatively, these results indicate that constitutive activation of PKG Iα proceeds through oxidation of Cys-117 and further suggest that the formation of a sulfur acid is necessary for this phenotype.
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Affiliation(s)
- Jessica L Sheehe
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Adrian D Bonev
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Anna M Schmoker
- the Department of Biology, University of Vermont, Burlington, Vermont 05405 and
| | - Bryan A Ballif
- the Department of Biology, University of Vermont, Burlington, Vermont 05405 and
| | - Mark T Nelson
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Thomas M Moon
- the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
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11
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Hart EC. Human hypertension, sympathetic activity and the selfish brain. Exp Physiol 2018; 101:1451-1462. [PMID: 27519960 DOI: 10.1113/ep085775] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/10/2016] [Indexed: 12/19/2022]
Abstract
NEW FINDINGS What is the topic of this review? This review article revisits an historical hypothesis that cerebral hypoperfusion, caused by elevated cerebral vascular resistances, causes the onset of high sympathetic nerve activity and hypertension in humans. What advances does it highlight? The review article highlights new evidence indicating that congenital cerebrovascular abnormalities, namely vertebral artery hypoplasia and an incomplete posterior circle of Willis, may play a role in the onset of hypertension. Despite the harmful consequences of high blood pressure (hypertension; e.g. stroke, renal failure, dementia and even death), the underlying physiological mechanisms that cause the onset of hypertension are poorly understood. The most established finding is that hypertension occurs alongside activation of the sympathetic nervous system, yet exactly what triggers this in humans is ambiguous. This review discusses evidence for elevated sympathetic nerve activity, particularly in human hypertension, and revisits an historical theory regarding the aetiology underlying human hypertension that was proposed by Seymour Kety and John Dickinson in the 1940s-1950s. My research group hypothesizes that elevated sympathetic nerve activity and hypertension develop as a fundamental mechanism to maintain adequate cerebral blood flow, which is now termed Cushing's mechanism or the selfish brain hypothesis. Moreover, it goes against the traditional belief that high cerebrovascular resistance is a consequence of hypertension; we propose that this elevated resistance drives hypertension. This review discusses historical and new evidence in animals and humans supporting this hypothesis. In particular, unique human data indicating a higher prevalence of congenital cerebral vascular abnormalities in hypertension are considered.
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Affiliation(s)
- Emma C Hart
- School of Physiology, Pharmacology and Neuroscience, Clinical Research and Imaging Centre, University of Bristol, Bristol, UK
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12
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Ronconi KDS, Stefanon I, Ribeiro Junior RF. Tributyltin and Vascular Dysfunction: The Role of Oxidative Stress. Front Endocrinol (Lausanne) 2018; 9:354. [PMID: 30050498 PMCID: PMC6052083 DOI: 10.3389/fendo.2018.00354] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 06/13/2018] [Indexed: 01/18/2023] Open
Abstract
The organotin compounds (OT) are used as fungicides, stabilizers in plastics, miticides, manufacturing and agricultural biocides, wood preservatives and antifouling agents. Tributyltin (TBT) is an OT that was first used for antifouling because it was the most effective agent to prevent undesirable accumulation of marine organisms on solid surfaces, such as ships' hulls or mechanical components, immersed in saltwater. TBT can be easily absorbed by mammals through ingestion, and its cytotoxic effects have become a major concern since their discovery in the 1970s. Recently, it has been demonstrated that TBT exposure is detrimental to the cardiovascular system. TBT is a membrane active substance and its action seems to depend on the OT lipophilicity. As a result, TBT crosses the cell membrane and damages the endothelium and the smooth muscle cells. TBT exposure induces vascular dysfunction, most likely due to endothelial dysfunction and morphological changes in the vascular wall. In an experimental rodent model, small doses of TBT (100 and 500 ng/kg/bw/day for 15 days) modified the vascular reactivity in aorta, mesenteric and coronary arteries followed by smooth muscle cell atrophy, increased collagen deposition and fibrin accumulation. TBT exposure increases oxidative stress by inducing vascular superoxide anion production derived from NADPH oxidase and decreases nitric oxide (NO) production as well as eNOS protein expression. The goal of this review is to summarize the current state of the art regarding the mechanisms involved in the vascular and endothelial dysfunction induced by TBT.
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Affiliation(s)
| | - Ivanita Stefanon
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, Brazil
| | - Rogerio F. Ribeiro Junior
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, Brazil
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
- *Correspondence: Rogerio F. Ribeiro Junior
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13
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Lai AY, McLaurin J. Rho-associated protein kinases as therapeutic targets for both vascular and parenchymal pathologies in Alzheimer's disease. J Neurochem 2017; 144:659-668. [PMID: 28722749 DOI: 10.1111/jnc.14130] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/21/2017] [Accepted: 07/14/2017] [Indexed: 12/30/2022]
Abstract
The causes of late-onset Alzheimer's disease are unclear and likely multifactorial. Rho-associated protein kinases (ROCKs) are ubiquitously expressed signaling messengers that mediate a wide array of cellular processes. Interestingly, they play an important role in several vascular and brain pathologies implicated in Alzheimer's etiology, including hypertension, hypercholesterolemia, blood-brain barrier disruption, oxidative stress, deposition of vascular and parenchymal amyloid-beta peptides, tau hyperphosphorylation, and cognitive decline. The current review summarizes the functions of ROCKs with respect to the various risk factors and pathologies on both sides of the blood-brain barrier and present support for targeting ROCK signaling as a multifactorial and multi-effect approach for the prevention and amelioration of late-onset Alzheimer's disease. This article is part of the Special Issue "Vascular Dementia".
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Affiliation(s)
- Aaron Y Lai
- Biological Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - JoAnne McLaurin
- Biological Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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14
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Li Y, Pagano PJ. Microvascular NADPH oxidase in health and disease. Free Radic Biol Med 2017; 109:33-47. [PMID: 28274817 PMCID: PMC5482368 DOI: 10.1016/j.freeradbiomed.2017.02.049] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/24/2017] [Accepted: 02/28/2017] [Indexed: 02/07/2023]
Abstract
The systemic and cerebral microcirculation contribute critically to regulation of local and global blood flow and perfusion pressure. Microvascular dysfunction, commonly seen in numerous cardiovascular pathologies, is associated with alterations in the oxidative environment including potentiated production of reactive oxygen species (ROS) and subsequent activation of redox signaling pathways. NADPH oxidases (Noxs) are a primary source of ROS in the vascular system and play a central role in cardiovascular health and disease. In this review, we focus on the roles of Noxs in ROS generation in resistance arterioles and capillaries, and summarize their contributions to microvascular physiology and pathophysiology in both systemic and cerebral microcirculation. In light of the accumulating evidence that Noxs are pivotal players in vascular dysfunction of resistance arterioles, selectively targeting Nox isozymes could emerge as a novel and effective therapeutic strategy for preventing and treating microvascular diseases.
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Affiliation(s)
- Yao Li
- Department of Pharmacology & Chemical Biology, Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Patrick J Pagano
- Department of Pharmacology & Chemical Biology, Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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15
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AT1 receptor signaling pathways in the cardiovascular system. Pharmacol Res 2017; 125:4-13. [PMID: 28527699 DOI: 10.1016/j.phrs.2017.05.008] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 01/14/2023]
Abstract
The importance of the renin angiotensin aldosterone system in cardiovascular physiology and pathophysiology has been well described whereas the detailed molecular mechanisms remain elusive. The angiotensin II type 1 receptor (AT1 receptor) is one of the key players in the renin angiotensin aldosterone system. The AT1 receptor promotes various intracellular signaling pathways resulting in hypertension, endothelial dysfunction, vascular remodeling and end organ damage. Accumulating evidence shows the complex picture of AT1 receptor-mediated signaling; AT1 receptor-mediated heterotrimeric G protein-dependent signaling, transactivation of growth factor receptors, NADPH oxidase and ROS signaling, G protein-independent signaling, including the β-arrestin signals and interaction with several AT1 receptor interacting proteins. In addition, there is functional cross-talk between the AT1 receptor signaling pathway and other signaling pathways. In this review, we will summarize an up to date overview of essential AT1 receptor signaling events and their functional significances in the cardiovascular system.
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16
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Hu X, De Silva TM, Chen J, Faraci FM. Cerebral Vascular Disease and Neurovascular Injury in Ischemic Stroke. Circ Res 2017; 120:449-471. [PMID: 28154097 PMCID: PMC5313039 DOI: 10.1161/circresaha.116.308427] [Citation(s) in RCA: 256] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/13/2016] [Accepted: 10/26/2016] [Indexed: 12/13/2022]
Abstract
The consequences of cerebrovascular disease are among the leading health issues worldwide. Large and small cerebral vessel disease can trigger stroke and contribute to the vascular component of other forms of neurological dysfunction and degeneration. Both forms of vascular disease are driven by diverse risk factors, with hypertension as the leading contributor. Despite the importance of neurovascular disease and subsequent injury after ischemic events, fundamental knowledge in these areas lag behind our current understanding of neuroprotection and vascular biology in general. The goal of this review is to address select key structural and functional changes in the vasculature that promote hypoperfusion and ischemia, while also affecting the extent of injury and effectiveness of therapy. In addition, as damage to the blood-brain barrier is one of the major consequences of ischemia, we discuss cellular and molecular mechanisms underlying ischemia-induced changes in blood-brain barrier integrity and function, including alterations in endothelial cells and the contribution of pericytes, immune cells, and matrix metalloproteinases. Identification of cell types, pathways, and molecules that control vascular changes before and after ischemia may result in novel approaches to slow the progression of cerebrovascular disease and lessen both the frequency and impact of ischemic events.
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Affiliation(s)
- Xiaoming Hu
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - T. Michael De Silva
- Biomedicine Discovery Institute, Department of Pharmacology, 9 Ancora Imparo Way, Monash University, Clayton, Vic, Australia
| | - Jun Chen
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Frank M. Faraci
- Departments of Internal Medicine and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City Veterans Affairs Healthcare System, Iowa City, IA, USA
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17
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Iadecola C, Yaffe K, Biller J, Bratzke LC, Faraci FM, Gorelick PB, Gulati M, Kamel H, Knopman DS, Launer LJ, Saczynski JS, Seshadri S, Zeki Al Hazzouri A. Impact of Hypertension on Cognitive Function: A Scientific Statement From the American Heart Association. Hypertension 2016; 68:e67-e94. [PMID: 27977393 DOI: 10.1161/hyp.0000000000000053] [Citation(s) in RCA: 423] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Age-related dementia, most commonly caused by Alzheimer disease or cerebrovascular factors (vascular dementia), is a major public health threat. Chronic arterial hypertension is a well-established risk factor for both types of dementia, but the link between hypertension and its treatment and cognition remains poorly understood. In this scientific statement, a multidisciplinary team of experts examines the impact of hypertension on cognition to assess the state of the knowledge, to identify gaps, and to provide future directions. METHODS Authors with relevant expertise were selected to contribute to this statement in accordance with the American Heart Association conflict-of-interest management policy. Panel members were assigned topics relevant to their areas of expertise, reviewed the literature, and summarized the available data. RESULTS Hypertension disrupts the structure and function of cerebral blood vessels, leads to ischemic damage of white matter regions critical for cognitive function, and may promote Alzheimer pathology. There is strong evidence of a deleterious influence of midlife hypertension on late-life cognitive function, but the cognitive impact of late-life hypertension is less clear. Observational studies demonstrated a cumulative effect of hypertension on cerebrovascular damage, but evidence from clinical trials that antihypertensive treatment improves cognition is not conclusive. CONCLUSIONS After carefully reviewing the literature, the group concluded that there were insufficient data to make evidence-based recommendations. However, judicious treatment of hypertension, taking into account goals of care and individual characteristics (eg, age and comorbidities), seems justified to safeguard vascular health and, as a consequence, brain health.
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18
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De Silva TM, Miller AA. Cerebral Small Vessel Disease: Targeting Oxidative Stress as a Novel Therapeutic Strategy? Front Pharmacol 2016; 7:61. [PMID: 27014073 PMCID: PMC4794483 DOI: 10.3389/fphar.2016.00061] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/04/2016] [Indexed: 12/25/2022] Open
Abstract
Cerebral small vessel disease (SVD) is a major contributor to stroke, and a leading cause of cognitive impairment and dementia. Despite the devastating effects of cerebral SVD, the pathogenesis of cerebral SVD is still not completely understood. Moreover, there are no specific pharmacological strategies for its prevention or treatment. Cerebral SVD is characterized by marked functional and structural abnormalities of the cerebral microcirculation. The clinical manifestations of these pathological changes include lacunar infarcts, white matter hyperintensities, and cerebral microbleeds. The main purpose of this review is to discuss evidence implicating oxidative stress in the arteriopathy of both non-amyloid and amyloid (cerebral amyloid angiopathy) forms of cerebral SVD and its most important risk factors (hypertension and aging), as well as its contribution to cerebral SVD-related brain injury and cognitive impairment. We also highlight current evidence of the involvement of the NADPH oxidases in the development of oxidative stress, enzymes that are a major source of reactive oxygen species in the cerebral vasculature. Lastly, we discuss potential pharmacological strategies for oxidative stress in cerebral SVD, including some of the historical and emerging NADPH oxidase inhibitors.
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Affiliation(s)
- T. Michael De Silva
- Department of Pharmacology, Biomedicine Discovery Institute, Monash UniversityMelbourne, VIC, Australia
| | - Alyson A. Miller
- Cerebrovascular and Stroke Laboratory, School of Health and Biomedical Sciences, RMIT UniversityMelbourne, VIC, Australia
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19
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Microvascular Dysfunction and Cognitive Impairment. Cell Mol Neurobiol 2016; 36:241-58. [PMID: 26988697 DOI: 10.1007/s10571-015-0308-1] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/19/2015] [Indexed: 12/18/2022]
Abstract
The impact of vascular risk factors on cognitive function has garnered much interest in recent years. The appropriate distribution of oxygen, glucose, and other nutrients by the cerebral vasculature is critical for proper cognitive performance. The cerebral microvasculature is a key site of vascular resistance and a preferential target for small vessel disease. While deleterious effects of vascular risk factors on microvascular function are known, the contribution of this dysfunction to cognitive deficits is less clear. In this review, we summarize current evidence for microvascular dysfunction in brain. We highlight effects of select vascular risk factors (hypertension, diabetes, and hyperhomocysteinemia) on the pial and parenchymal circulation. Lastly, we discuss potential links between microvascular disease and cognitive function, highlighting current gaps in our understanding.
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20
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Umesalma S, Houwen FK, Baumbach GL, Chan SL. Roles of Caveolin-1 in Angiotensin II-Induced Hypertrophy and Inward Remodeling of Cerebral Pial Arterioles. Hypertension 2016; 67:623-9. [PMID: 26831194 DOI: 10.1161/hypertensionaha.115.06565] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/03/2015] [Indexed: 11/16/2022]
Abstract
Angiotensin II (Ang II) is a major determinant of inward remodeling and hypertrophy in pial arterioles that may have an important role in stroke during chronic hypertension. Previously, we found that epidermal growth factor receptor is critical in Ang II-mediated hypertrophy that may involve caveolin-1 (Cav-1). In this study, we examined the effects of Cav-1 and matrix metalloproteinase-9 (MMP9) on Ang II-mediated structural changes in pial arterioles. Cav-1-deficient (Cav-1(-/-)), MMP9-deficient (MMP9(-/-)), and wild-type mice were infused with either Ang II (1000 ng/kg per minute) or saline via osmotic minipumps for 28 days (n=6-8 per group). Systolic arterial pressure was measured by a tail-cuff method. Pressure and diameter of pial arterioles were measured through an open cranial window in anesthetized mice. Cross-sectional area of the wall was determined histologically in pressurized fixed pial arterioles. Expression of Cav-1, MMP9, phosphorylated epidermal growth factor receptor, and Akt was determined by Western blotting and immunohistochemistry. Deficiency of Cav-1 or MMP9 did not affect Ang II-induced hypertension. Ang II increased the expression of Cav-1, phosphorylated epidermal growth factor receptor, and Akt in wild-type mice, which was attenuated in Cav-1(-/-) mice. Ang II-induced hypertrophy, inward remodeling, and increased MMP9 expression in pial arterioles were prevented in Cav-1(-/-) mice. Ang II-mediated increases in MMP9 expression and inward remodeling, but not hypertrophy, were prevented in MMP9(-/-) mice. In conclusion, Cav-1 is essential in Ang II-mediated inward remodeling and hypertrophy in pial arterioles. Cav-1-induced MMP9 is exclusively involved in inward remodeling, not hypertrophy. Further studies are needed to determine the role of Akt in Ang II-mediated hypertrophy.
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Affiliation(s)
- Shaikamjad Umesalma
- From the Department of Pathology, University of Iowa College of Medicine, Iowa City (S.U., F.K.H., G.L.B.); and Department of Neurological Sciences, University of Vermont, Burlington (S.-L.C.)
| | - Frederick Keith Houwen
- From the Department of Pathology, University of Iowa College of Medicine, Iowa City (S.U., F.K.H., G.L.B.); and Department of Neurological Sciences, University of Vermont, Burlington (S.-L.C.)
| | - Gary L Baumbach
- From the Department of Pathology, University of Iowa College of Medicine, Iowa City (S.U., F.K.H., G.L.B.); and Department of Neurological Sciences, University of Vermont, Burlington (S.-L.C.).
| | - Siu-Lung Chan
- From the Department of Pathology, University of Iowa College of Medicine, Iowa City (S.U., F.K.H., G.L.B.); and Department of Neurological Sciences, University of Vermont, Burlington (S.-L.C.).
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21
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Li L, Feng D, Luo Z, Welch WJ, Wilcox CS, Lai EY. Remodeling of Afferent Arterioles From Mice With Oxidative Stress Does Not Account for Increased Contractility but Does Limit Excessive Wall Stress. Hypertension 2015; 66:550-6. [PMID: 26101341 DOI: 10.1161/hypertensionaha.115.05631] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 05/27/2015] [Indexed: 11/16/2022]
Abstract
Because superoxide dismutase (SOD) knockout enhances arteriolar remodeling and contractility, we hypothesized that remodeling enhances contractility. In the isolated and perfused renal afferent arterioles from SOD wild type (+/+) and gene-deleted mice, contractility was assessed from reductions in luminal diameter with perfusion pressure from 40 to 80 mm Hg (myogenic responses) or angiotensin II (10(-6) mol/L), remodeling from media:lumen area ratio, superoxide (O2 (·-)) and hydrogen peroxide (H2O2) from fluorescence microscopy, and wall stress from wall tension/wall thickness. Compared with +/+ strains, arterioles from SOD1-/-, SOD2+/-, and SOD3-/- mice developed significantly (P<0.05) more O2 (·-) with perfusion pressure and angiotensin II and significantly increased myogenic responses (SOD1-/-: -20.7±2.2% versus -12.7±1.6%; SOD2+/-: -7.4±1.3% versus -12.6±1.4%; and SOD3-/-: -9.1±1.9% versus -15.8±2.2%) and angiotensin II contractions and ≈2-fold increased media:lumen ratios. Media:lumen ratios correlated with myogenic responses (r(2) =0.23; P<0.01), angiotensin II contractions (r(2)=0.57; P<0.0001), and active wall tension (r(2) =0.19; P<0.01), but not with active wall stress (r(2)=0.08; NS). Differences in myogenic responses among SOD3 mice were abolished by bath addition of SOD and were increased 3 days after inducing SOD3 knockout (-26.9±1.7% versus -20.1±0.7%; P<0.05), despite unchanged media:lumen ratios (2.01±0.09 versus 2.02±0.03; NS). We conclude that cytosolic, mitochondrial, or extracellular O2 (·-) enhance afferent arteriolar contractility and remodeling. Although remodeling does not enhance contractility, it does prevent the potentially damaging effects of increased wall stress.
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Affiliation(s)
- Lingli Li
- From the Department of Medicine, Division of Nephrology and Hypertension, Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, DC (L.L., D.F., Z.L., W.J.W., C.S.W., E.Y.L.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L.)
| | - Di Feng
- From the Department of Medicine, Division of Nephrology and Hypertension, Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, DC (L.L., D.F., Z.L., W.J.W., C.S.W., E.Y.L.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L.)
| | - Zaiming Luo
- From the Department of Medicine, Division of Nephrology and Hypertension, Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, DC (L.L., D.F., Z.L., W.J.W., C.S.W., E.Y.L.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L.)
| | - William J Welch
- From the Department of Medicine, Division of Nephrology and Hypertension, Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, DC (L.L., D.F., Z.L., W.J.W., C.S.W., E.Y.L.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L.)
| | - Christopher S Wilcox
- From the Department of Medicine, Division of Nephrology and Hypertension, Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, DC (L.L., D.F., Z.L., W.J.W., C.S.W., E.Y.L.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L.)
| | - En Yin Lai
- From the Department of Medicine, Division of Nephrology and Hypertension, Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, DC (L.L., D.F., Z.L., W.J.W., C.S.W., E.Y.L.); and Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China (E.Y.L.).
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NADPH Oxidase Activity in Cerebral Arterioles Is a Key Mediator of Cerebral Small Vessel Disease-Implications for Prevention. Healthcare (Basel) 2015; 3:233-51. [PMID: 27417759 PMCID: PMC4939544 DOI: 10.3390/healthcare3020233] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 03/21/2015] [Accepted: 04/08/2015] [Indexed: 02/05/2023] Open
Abstract
Cerebral small vessel disease (SVD), a common feature of brain aging, is characterized by lacunar infarcts, microbleeds, leukoaraiosis, and a leaky blood-brain barrier. Functionally, it is associated with cognitive decline, dementia, depression, gait abnormalities, and increased risk for stroke. Cerebral arterioles in this syndrome tend to hypertrophy and lose their capacity for adaptive vasodilation. Rodent studies strongly suggest that activation of Nox2-dependent NADPH oxidase activity is a crucial driver of these structural and functional derangements of cerebral arterioles, in part owing to impairment of endothelial nitric oxide synthase (eNOS) activity. This oxidative stress may also contribute to the breakdown of the blood-brain barrier seen in SVD. Hypertension, aging, metabolic syndrome, smoking, hyperglycemia, and elevated homocysteine may promote activation of NADPH oxidase in cerebral arterioles. Inhibition of NADPH oxidase with phycocyanobilin from spirulina, as well as high-dose statin therapy, may have potential for prevention and control of SVD, and high-potassium diets merit study in this regard. Measures which support effective eNOS activity in other ways-exercise training, supplemental citrulline, certain dietary flavonoids (as in cocoa and green tea), and capsaicin, may also improve the function of cerebral arterioles. Asian epidemiology suggests that increased protein intakes may decrease risk for SVD; conceivably, arginine and/or cysteine-which boosts tissue glutathione synthesis, and can be administered as N-acetylcysteine-mediate this benefit. Ameliorating the risk factors for SVD-including hypertension, metabolic syndrome, hyperglycemia, smoking, and elevated homocysteine-also may help to prevent and control this syndrome, although few clinical trials have addressed this issue to date.
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Chan SL, Umesalma S, Baumbach GL. Epidermal growth factor receptor is critical for angiotensin II-mediated hypertrophy in cerebral arterioles. Hypertension 2015; 65:806-12. [PMID: 25733240 DOI: 10.1161/hypertensionaha.114.04794] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Angiotensin II (Ang II) is a major determinant of vascular remodeling in the cerebral circulation during chronic hypertension, which is an important risk factor for stroke. We examined the molecular mechanism of Ang II-mediated cerebrovascular remodeling that involves the epidermal growth factor receptor (EGFR) pathway. Mutant EGFR mice (waved-2), their heterozygous control (wild-type [WT]), and C57BL/6J mice were infused with Ang II (1000 ng kg(-1) min(-1)) or saline via osmotic minipumps for 28 days (n=8 per group). Eight of the Ang II-infused C57BL/6J mice were cotreated with AG1478 (12 mg/kg per day, IP), a specific EGFR tyrosine kinase inhibitor. Systolic arterial pressure was measured by a tail-cuff method. Pressure and diameter of cerebral arterioles were measured through an open cranial window in anesthetized mice. Cross-sectional area of the wall was determined in pressurized fixed cerebral arterioles. Expression of phosphorylated EGFR (p-EGFR), caveolin-1 (Cav-1), and c-Src was determined by western blotting and immunohistochemistry. Mutation of EGFR or AG1478 treatment did not affect Ang II-induced hypertension. Ang II increased the expression of p-EGFR in WT mice, confirming the activation of EGFR. Ang II induced hypertrophy and inward remodeling of cerebral arterioles in WT mice. Hypertrophy, but not remodeling, was prevented in waved-2 and AG1478-treated C57BL/6J mice. Ang II increased p-EGFR, Cav-1, and c-Src expression in WT but not in waved-2 or AG1478-treated C57BL/6J mice. These results suggest that Ang II-induced hypertrophy in cerebral arterioles involves EGFR-dependent signaling and may include Cav-1 and nonreceptor tyrosine kinase c-Src. This signaling pathway seems to be limited to Ang II-induced hypertrophy, but not inward remodeling, and is independent of blood pressure.
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Affiliation(s)
- Siu-Lung Chan
- From the Department of Pathology, University of Iowa College of Medicine, Iowa City
| | - Shaikamjad Umesalma
- From the Department of Pathology, University of Iowa College of Medicine, Iowa City
| | - Gary L Baumbach
- From the Department of Pathology, University of Iowa College of Medicine, Iowa City.
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Mitochondrial regulation of NADPH oxidase in hindlimb unweighting rat cerebral arteries. PLoS One 2014; 9:e95916. [PMID: 24759683 PMCID: PMC3997512 DOI: 10.1371/journal.pone.0095916] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 04/01/2014] [Indexed: 02/07/2023] Open
Abstract
Exposure to microgravity results in post-flight cardiovascular deconditioning and orthostatic intolerance in astronauts. Vascular oxidative stress injury and mitochondrial dysfunction have been indicated in this process. To elucidate the mechanism for this condition, we investigated whether mitochondria regulated NADPH oxidase in hindlimb unweighting (HU) rat cerebral and mesenteric arteries. Four-week HU was used to simulate microgravity in rats. Vascular superoxide generation, protein and mRNA levels of Nox2/Nox4, and the activity of NADPH oxidase were examined in the present study. Compared with control rats, the levels of superoxide increased in cerebral (P<0.001) but not in mesenteric vascular smooth muscle cells. The protein and mRNA levels of Nox2 and Nox4 were upregulated significantly (P<0.001 and P<0.001 for Nox2, respectively; P<0.001 and P<0.001 for Nox4, respectively) in HU rat cerebral arteries but not in mesenteric arteries. NADPH oxidases were activated significantly by HU (P<0.001) in cerebral arteries but not in mesenteric arteries. Chronic treatment with mitochondria-targeted antioxidant mitoTEMPO attenuated superoxide levels (P<0.001), decreased the protein and mRNA expression levels of Nox2/Nox4 (P<0.01 and P<0.05 for Nox2, respectively; P<0.001 and P<0.001 for Nox4, respectively) and the activity of NADPH oxidase (P<0.001) in HU rat cerebral arteries, but exerted no effects on HU rat mesenteric arteries. Therefore, mitochondria regulated the expression and activity of NADPH oxidases during simulated microgravity. Both mitochondria and NADPH oxidase participated in vascular redox status regulation.
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