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Şeren N, Dovinova I, Birim D, Kaftan G, Barancik M, Erdogan MA, Armagan G. Regulation of tight junction proteins and cell death by peroxisome proliferator-activated receptor γ agonist in brainstem of hypertensive rats. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:411-421. [PMID: 37458776 DOI: 10.1007/s00210-023-02619-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 07/10/2023] [Indexed: 01/07/2024]
Abstract
The decrease in tight junction proteins and their adapter proteins in the hypertensive brain is remarkable. Here, we aimed to investigate tight junction proteins and peroxisome proliferator-activated receptor (PPARγ) activation as well as inflammation factors and cell death proteins in the brainstem of hypertension models, namely spontaneously hypertensive rats (SHR) and borderline hypertensive rats (BHR). At first, SHR and BHR groups were treated with PPARγ agonist, pioglitazone. Then, occludin, claudin-1, claudin-2, claudin-12, ZO-1, and NF-κB p65 gene expression levels; pIKKβ, NF-κB p65, TNF, IL-1β, caspase-3, caspase-9 levels, and PARP-1 cleavage were evaluated. Significantly lower pIKKβ, NF-κB p65, TNF, and IL-1β levels were measured in pioglitazone-treated SHR. Results from this study confirm higher occludin (1.35-fold), claudin-2 (7.45-fold), claudin-12 (1.12-fold), and NF-κB p65 subunit (4.76-fold) expressions in the BHR group when compared to the SHR group. Pioglitazone was found effective in terms of regulating gene expression in SHR. Pioglitazone significantly increased occludin (8.17-fold), claudin-2 (2.41-fold), and claudin-12 (1.85-fold) mRNA levels, which were accompanied by decreased cleaved caspase-3, caspase-9 levels, PARP-1 activation, and proinflammatory factor levels in SHR (p ˂ 0.05). Our work has led us to conclude that alterations in tight junction proteins, particularly occludin, and cell death parameters in the brainstem following PPARγ activation may contribute to neuroprotection in essential hypertension.
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Affiliation(s)
- Nazlıcan Şeren
- Master Program in Biochemistry, Graduate School of Health Sciences, Ege University, 35100, Bornova, Izmir, Turkey
| | - Ima Dovinova
- Centre of Experimental Medicine, Institute for Heart Research, Slovak Academy of Sciences, Dubravska Cesta 9, 84104, Bratislava, Slovakia
| | - Derviş Birim
- Department of Biochemistry, Faculty of Pharmacy, Ege University, 35100, Bornova, Izmir, Turkey
- Doctorate Program in Biochemistry, Graduate School of Health Sciences, Ege University, 35100, Bornova, Izmir, Turkey
| | - Gizem Kaftan
- Doctorate Program in Biochemistry, Graduate School of Health Sciences, Ege University, 35100, Bornova, Izmir, Turkey
- Department of Biochemistry, Faculty of Pharmacy, Afyonkarahisar Health Sciences University, 03100, Afyonkarahisar, Turkey
| | - Miroslav Barancik
- Centre of Experimental Medicine, Institute for Heart Research, Slovak Academy of Sciences, Dubravska Cesta 9, 84104, Bratislava, Slovakia
| | - Mumin Alper Erdogan
- Department of Physiology, Faculty of Medicine, Izmir Katip Celebi University, 35610, Izmir, Turkey
| | - Güliz Armagan
- Department of Biochemistry, Faculty of Pharmacy, Ege University, 35100, Bornova, Izmir, Turkey.
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2
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Hu JR, Abdullah A, Nanna MG, Soufer R. The Brain-Heart Axis: Neuroinflammatory Interactions in Cardiovascular Disease. Curr Cardiol Rep 2023; 25:1745-1758. [PMID: 37994952 PMCID: PMC10908342 DOI: 10.1007/s11886-023-01990-8] [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] [Accepted: 10/30/2023] [Indexed: 11/24/2023]
Abstract
PURPOSE OF REVIEW The role of neuroimmune modulation and inflammation in cardiovascular disease has been historically underappreciated. Physiological connections between the heart and brain, termed the heart-brain axis (HBA), are bidirectional, occur through a complex network of autonomic nerves/hormones and cytokines, and play important roles in common disorders. RECENT FINDINGS At the molecular level, advances in the past two decades reveal complex crosstalk mediated by the sympathetic and parasympathetic nervous systems, the renin-angiotensin aldosterone and hypothalamus-pituitary axes, microRNA, and cytokines. Afferent pathways amplify proinflammatory signals via the hypothalamus and brainstem to the periphery, promoting neurogenic inflammation. At the organ level, while stress-mediated cardiomyopathy is the prototypical disorder of the HBA, cardiac dysfunction can result from a myriad of neurologic insults including stroke and spinal injury. Atrial fibrillation is not necessarily a causative factor for cardioembolic stroke, but a manifestation of an abnormal atrial substrate, which can lead to the development of stroke independent of AF. Central and peripheral neurogenic proinflammatory factors have major roles in the HBA, manifesting as complex bi-directional relationships in common conditions such as stroke, arrhythmia, and cardiomyopathy.
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Affiliation(s)
- Jiun-Ruey Hu
- Section of Cardiovascular Medicine, Yale School of Medicine, 789 Howard Ave, New Haven, CT, 06519, USA
| | - Ahmed Abdullah
- Section of Cardiovascular Medicine, Yale School of Medicine, 789 Howard Ave, New Haven, CT, 06519, USA
| | - Michael G Nanna
- Section of Cardiovascular Medicine, Yale School of Medicine, 789 Howard Ave, New Haven, CT, 06519, USA
| | - Robert Soufer
- Section of Cardiovascular Medicine, Yale School of Medicine, 789 Howard Ave, New Haven, CT, 06519, USA.
- VA Connecticut Healthcare System, 950 Campbell Ave, -111B, West Haven, CT, 06516, USA.
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3
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Pauziene N, Ranceviene D, Rysevaite-Kyguoliene K, Inokaitis H, Saburkina I, Plekhanova K, Sabeckiene D, Sabeckis I, Martinaityte R, Pilnikovaite E, Pauza DH. Comparative analysis of intracardiac neural structures in the aged rats with essential hypertension. Anat Rec (Hoboken) 2023; 306:2313-2332. [PMID: 36342958 DOI: 10.1002/ar.25109] [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: 06/08/2022] [Revised: 09/16/2022] [Accepted: 10/09/2022] [Indexed: 11/09/2022]
Abstract
Persistent arterial hypertension initiates cardiac autonomic imbalance and alters cardiac tissues. Previous studies have shown that neural component contributes to arterial hypertension etiology, maintenance, and progression and leads to brain damage, peripheral neuropathy, and remodeling of intrinsic cardiac neural plexus. Recently, significant structural changes of the intracardiac neural plexus were demonstrated in young prehypertensive and adult hypertensive spontaneously hypertensive rats (SHR), yet structural alterations of intracardiac neural plexus that occur in the aged SHR remain undetermined. Thus, we analyzed the impact of uncontrolled arterial hypertension in old (48-52 weeks) SHR and the age-matched Wistar-Kyoto rats (WKY). Intrinsic cardiac neural plexus was examined using a combination of immunofluorescence confocal microscopy and transmission electron microscopy in cardiac sections and whole-mount preparations. Our findings demonstrate that structural changes of intrinsic cardiac neural plexus caused by arterial hypertension are heterogeneous and may support recent physiological implications about cardiac denervation occurring together with the hyperinnervation of the SHR heart. We conclude that arterial hypertension leads to (i) the decrease of the neuronal body area, the thickness of atrial nerves, the number of myelinated nerve fibers, unmyelinated axon area and cumulative axon area in the nerve, and the density of myocardial nerve fibers, and (ii) the increase in myelinated nerve fiber area and density of neuronal bodies within epicardiac ganglia. Despite neuropathic alterations of myelinated fibers were exposed within intracardiac nerves of both groups, SHR and WKY, we consider that the determined significant changes in structure of intrinsic cardiac neural plexus were predisposed by arterial hypertension.
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Affiliation(s)
| | | | | | | | - Inga Saburkina
- Lithuanian University of Health Sciences, Kaunas, Lithuania
| | | | | | - Ignas Sabeckis
- Lithuanian University of Health Sciences, Kaunas, Lithuania
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4
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Lamptey RNL, Sun C, Layek B, Singh J. Neurogenic Hypertension, the Blood-Brain Barrier, and the Potential Role of Targeted Nanotherapeutics. Int J Mol Sci 2023; 24:ijms24032213. [PMID: 36768536 PMCID: PMC9916775 DOI: 10.3390/ijms24032213] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/26/2023] Open
Abstract
Hypertension is a major health concern globally. Elevated blood pressure, initiated and maintained by the brain, is defined as neurogenic hypertension (NH), which accounts for nearly half of all hypertension cases. A significant increase in angiotensin II-mediated sympathetic nervous system activity within the brain is known to be the key driving force behind NH. Blood pressure control in NH has been demonstrated through intracerebrovascular injection of agents that reduce the sympathetic influence on cardiac functions. However, traditional antihypertensive agents lack effective brain permeation, making NH management extremely challenging. Therefore, developing strategies that allow brain-targeted delivery of antihypertensives at the therapeutic level is crucial. Targeting nanotherapeutics have become popular in delivering therapeutics to hard-to-reach regions of the body, including the brain. Despite the frequent use of nanotherapeutics in other pathological conditions such as cancer, their use in hypertension has received very little attention. This review discusses the underlying pathophysiology and current management strategies for NH, as well as the potential role of targeted therapeutics in improving current treatment strategies.
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Affiliation(s)
| | | | - Buddhadev Layek
- Correspondence: (B.L.); (J.S.); Tel.: +1-701-231-7906 (B.L.); +1-701-231-7943 (J.S.); Fax: +1-701-231-8333 (B.L. & J.S.)
| | - Jagdish Singh
- Correspondence: (B.L.); (J.S.); Tel.: +1-701-231-7906 (B.L.); +1-701-231-7943 (J.S.); Fax: +1-701-231-8333 (B.L. & J.S.)
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5
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Contrasting Roles of Ang II and ACEA in the Regulation of IL10 and IL1β Gene Expression in Primary SHR Astroglial Cultures. Molecules 2021; 26:molecules26103012. [PMID: 34069330 PMCID: PMC8158781 DOI: 10.3390/molecules26103012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 12/14/2022] Open
Abstract
Angiotensin (Ang) II is well-known to have potent pro-oxidant and pro-inflammatory effects in the brain. Extensive crosstalk between the primary Ang II receptor, Ang type 1 receptor (AT1R), and the cannabinoid type 1 receptor (CB1R) has been demonstrated by various groups in the last decade. Since activation of glial CB1R has been demonstrated to play a key role in the resolution of inflammatory states, we investigated the role of Ang II (100 nM) and/or ACEA (10 nM), a potent CB1R-specific agonist in the regulation of inflammatory markers in astrocytes from spontaneously hypertensive rats (SHR) and Wistar rats. Astrocytes were cultured from brainstems and cerebellums of SHR and Wistar rats and assayed for IL1β and IL10 gene expression and secreted fraction, in treated and non-treated cells, by employing qPCR and ELISA, respectively. mRNA expression of both IL10 and IL1β were significantly elevated in untreated brainstem and cerebellar astrocytes isolated from SHR when compared to Wistar astrocytes. No changes were observed in the secreted fraction. While ACEA-treatment resulted in a significant increase in IL10 gene expression in Wistar brainstem astrocytes (Log2FC ≥ 1, p < 0.05), its effect in SHR brainstem astrocytes was diminished. Ang II treatment resulted in a strong inhibitory effect on IL10 gene expression in astrocytes from both brain regions of SHR and Wistar rats (Log2FC ≤ -1, p < 0.05), and an increase in IL1β gene expression in brainstem astrocytes from both strains (Log2FC ≥ 1, p < 0.05). Co-treatment of Ang II and ACEA resulted in neutralization of Ang II-mediated effect in Wistar brainstem and cerebellar astrocytes, but not SHR astrocytes. Neither Ang II nor ACEA resulted in any significant changes in IL10 or IL1β secreted proteins. These data suggest that Ang II and ACEA have opposing roles in the regulation of inflammatory gene signature in astrocytes isolated from SHR and Wistar rats. This however does not translate into changes in their secreted fractions.
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6
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Cell seeding accelerates the vascularization of tissue engineering constructs in hypertensive mice. Hypertens Res 2020; 44:23-35. [PMID: 32778779 DOI: 10.1038/s41440-020-0524-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 11/08/2022]
Abstract
Rapid blood vessel ingrowth into transplanted constructs represents the key requirement for successful tissue engineering. Seeding three-dimensional scaffolds with suitable cells is an approved technique for this challenge. Since a plethora of patients suffer from widespread diseases that limit the capacity of neoangiogenesis (e.g., hypertension), we investigated the incorporation of cell-seeded poly-L-lactide-co-glycolide scaffolds in hypertensive (BPH/2J, group A) and nonhypertensive (BPN/3J, group B) mice. Collagen-coated scaffolds (A1 and B1) were additionally seeded with osteoblast-like (A2 and B2) and mesenchymal stem cells (A3 and B3). After implantation into dorsal skinfold chambers, inflammation and newly formed microvessels were measured using repetitive intravital fluorescence microscopy for 2 weeks. Apart from a weak inflammatory response in all groups, significantly increased microvascular densities were found in cell-seeded scaffolds (day 14, A2: 192 ± 12 cm/cm2, A3: 194 ± 10 cm/cm2, B2: 249 ± 19 cm/cm2, B3: 264 ± 17 cm/cm2) when compared with controls (A1: 129 ± 10 cm/cm2, B1: 185 ± 8 cm/cm2). In this context, hypertensive mice showed reduced neoangiogenesis in comparison with nonhypertensive animals. Therefore, seeding approved scaffolds with organ-specific or pluripotent cells is a very promising technique for tissue engineering in hypertensive organisms.
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7
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Espinoza L, Boychuk CR. Diabetes, and its treatment, as an effector of autonomic nervous system circuits and its functions. Curr Opin Pharmacol 2020; 54:18-26. [PMID: 32721846 DOI: 10.1016/j.coph.2020.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 06/18/2020] [Accepted: 06/22/2020] [Indexed: 12/24/2022]
Abstract
Diabetes increases the risk of cardiovascular complications, including heart failure, hypertension, and stroke. There is a strong involvement of autonomic dysfunction in individuals with diabetes that exhibit clinical manifestations of cardiovascular diseases (CVD). Still, the mechanisms by which diabetes and its treatments alter autonomic function and subsequently affect cardiovascular complications remain elusive. For this reason, understanding the brainstem circuits involved in sensing metabolic state(s) and enacting autonomic control of the cardiovascular system are important to develop more comprehensive therapies for individuals with diabetes at increased risk for CVD. We review how autonomic nervous system circuits change during these disease states and discuss their potential role in current pharmacotherapies that target diabetic states. Overall, this review proposes that the brainstem circuits provide an integrative sensorimotor network capable of responding to metabolic cues to regulate cardiovascular function and this network is modified by, and in turn affects, diabetes-induced CVD and its treatment.
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Affiliation(s)
- Liliana Espinoza
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, United States
| | - Carie R Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, United States.
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8
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Martyniuk CJ, Martínez R, Kostyniuk DJ, Mennigen JA, Zubcevic J. Genetic ablation of bone marrow beta-adrenergic receptors in mice modulates miRNA-transcriptome networks of neuroinflammation in the paraventricular nucleus. Physiol Genomics 2020; 52:169-177. [PMID: 32089076 PMCID: PMC7191424 DOI: 10.1152/physiolgenomics.00001.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/07/2020] [Accepted: 02/16/2020] [Indexed: 12/21/2022] Open
Abstract
Elucidating molecular pathways regulating neuroimmune communication is critical for therapeutic interventions in conditions characterized by overactive immune responses and dysfunctional autonomic nervous system. We generated a bone marrow-specific adrenergic beta 1 and beta 2 knockout mouse chimera (AdrB1.B2 KO) to determine how sympathetic drive to the bone affects transcripts and miRNAs in the hypothalamic paraventricular nucleus (PVN). This model has previously exhibited a dampened systemic immune response and decreased blood pressure compared with control animals. Reduced sympathetic responsiveness of the bone marrow hematopoietic cells of AdrB1.B2 KO chimera led to suppression of transcriptional networks that included leukocyte cell adhesion and migration and T cell-activation and recruitment. Transcriptome responses related to IL-17a signaling and the renin-angiotensin system were also suppressed in the PVN. Based on the transcriptome response, we next computationally predicted miRNAs in the PVN that may underscore the reduced sympathetic responsiveness of the bone marrow cells. These included miR-27b-3p, miR-150, miR-223-3p, and miR-326. Using real-time PCR, we measured a downregulation in the expression of miR-150-5p, miR-205-5p, miR-223-3p, miR-375-5p, miR-499a-5p, miR-27b-3p, let-7a-5p, and miR-21a-5p in the PVN of AdrB1.B2 KO chimera, confirming computational predictions that these miRNAs are associated with reduced neuro-immune responses and the loss of sympathetic responsiveness in the bone marrow. Intriguingly, directional responses of the miRNA corresponded to mRNAs, suggesting complex temporal or circuit-dependent posttranscriptional control of gene expression in the PVN. This study identifies molecular pathways involved in neural-immune interactions that may act as targets of therapeutic intervention for a dysfunctional autonomic nervous system.
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Affiliation(s)
- Christopher J Martyniuk
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Ruben Martínez
- Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Jordi Girona, Barcelona, Spain
- Department of Cellular Biology, Physiology and Immunology, Universidad de Barcelona (UB), Barcelona, Spain
| | | | - Jan A Mennigen
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Jasenka Zubcevic
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
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9
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Donertas Ayaz B, Zubcevic J. Gut microbiota and neuroinflammation in pathogenesis of hypertension: A potential role for hydrogen sulfide. Pharmacol Res 2020; 153:104677. [PMID: 32023431 PMCID: PMC7056572 DOI: 10.1016/j.phrs.2020.104677] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/27/2019] [Accepted: 01/27/2020] [Indexed: 02/06/2023]
Abstract
Inflammation and gut dysbiosis are hallmarks of hypertension (HTN). Hydrogen sulfide (H2S) is an important freely diffusing molecule that modulates the function of neural, cardiovascular and immune systems, and circulating levels of H2S are reduced in animals and humans with HTN. While most research to date has focused on H₂S produced endogenously by the host, H2S is also produced by the gut bacteria and may affect the host homeostasis. Here, we review an association between neuroinflammation and gut dysbiosis in HTN, with special emphasis on a potential role of H2S in this interplay.
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Affiliation(s)
- Basak Donertas Ayaz
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States; Department of Pharmacology, College of Medicine, University of Eskisehir Osmangazi, Eskisehir, Turkey
| | - Jasenka Zubcevic
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States.
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10
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Walas D, Nowicki-Osuch K, Alibhai D, von Linstow Roloff E, Coghill J, Waterfall C, Paton JF. Inflammatory pathways are central to posterior cerebrovascular artery remodelling prior to the onset of congenital hypertension. J Cereb Blood Flow Metab 2019; 39:1803-1817. [PMID: 29651914 PMCID: PMC6724458 DOI: 10.1177/0271678x18769180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cerebral artery hypoperfusion may provide the basis for linking ischemic stroke with hypertension. Brain hypoperfusion may induce hypertension that may serve as an auto-protective mechanism to prevent ischemic stroke. We hypothesised that hypertension is caused by remodelling of the cerebral arteries, which is triggered by inflammation. We used a congenital rat model of hypertension and examined age-related changes in gene expression of the cerebral arteries using RNA sequencing. Prior to hypertension, we found changes in signalling pathways associated with the immune system and fibrosis. Validation studies using second harmonics generation microscopy revealed upregulation of collagen type I and IV in both tunica externa and media. These changes in the extracellular matrix of cerebral arteries pre-empted hypertension accounting for their increased stiffness and resistance, both potentially conducive to stroke. These data indicate that inflammatory driven cerebral artery remodelling occurs prior to the onset of hypertension and may be a trigger elevating systemic blood pressure in genetically programmed hypertension.
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Affiliation(s)
- Dawid Walas
- 1 School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | | | - Dominic Alibhai
- 3 Wolfson Bioimaging Facility, School of Biochemistry, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Eva von Linstow Roloff
- 1 School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Jane Coghill
- 4 Genomics Facility, School of Biological Sciences, Bristol, UK
| | | | - Julian Fr Paton
- 1 School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.,5 Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Grafton, New Zealand
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11
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Lambert GW, Schlaich MP, Eikelis N, Lambert EA. Sympathetic activity in obesity: a brief review of methods and supportive data. Ann N Y Acad Sci 2019; 1454:56-67. [PMID: 31268175 DOI: 10.1111/nyas.14140] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/11/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022]
Abstract
The increase in the prevalence of obesity and the concomitant rise in obesity-related illness have led to substantial pressure on health care systems throughout the world. While the combination of reduced exercise, increased sedentary time, poor diet, and genetic predisposition is undoubtedly pivotal in generating obesity and increasing disease risk, a large body of work indicates that the sympathetic nervous system (SNS) contributes to obesity-related disease development and progression. In obesity, sympathetic nervous activity is regionalized, with activity in some outflows being particularly sensitive to the obese state, whereas other outflows, or responses to stimuli, may be blunted, thereby making the assessment of sympathetic nervous activation in the clinical setting difficult. Isotope dilution methods and direct nerve recording techniques have been developed and utilized in clinical research, demonstrating that in obesity there is preferential activation of the muscle vasoconstrictor and renal sympathetic outflows. With weight loss, sympathetic activity is reduced. Importantly, sympathetic nervous activity is associated with end-organ dysfunction and changes in sympathetic activation that accompany weight loss are often reflected in an improvement of end-organ function. Whether targeting the SNS directly improves obesity-related illness remains unknown, but merits further attention.
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Affiliation(s)
- Gavin W Lambert
- The Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Victoria, Australia.,The School of Health Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Markus P Schlaich
- Dobney Hypertension Centre, School of Medicine, Royal Perth Hospital Unit, University of Western Australia, Perth, Western Australia, Australia
| | - Nina Eikelis
- The Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Victoria, Australia.,The School of Health Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Elisabeth A Lambert
- The Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Victoria, Australia.,The School of Health Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia
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12
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Olesen ND, Nielsen HB, Olsen NV, Secher NH. The age-related reduction in cerebral blood flow affects vertebral artery more than internal carotid artery blood flow. Clin Physiol Funct Imaging 2019; 39:255-260. [PMID: 30897269 DOI: 10.1111/cpf.12568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 03/18/2019] [Indexed: 11/26/2022]
Abstract
Ageing reduces cerebral blood flow (CBF), while mean arterial pressure (MAP) becomes elevated. According to 'the selfish brain' hypothesis of hypertension, a reduction in vertebral artery blood flow (VA) leads to increased sympathetic activity and thus increases MAP. In twenty-two young (24 ± 3 years; mean ± SD) and eleven elderly (70 ± 5 years) normotensive men, duplex ultrasound evaluated whether the age-related reduction in CBF affects VA more than internal carotid artery (ICA) blood flow. Pulse-contour analysis evaluated MAP while near-infrared spectroscopy determined frontal lobe oxygenation and transcranial Doppler middle cerebral artery mean blood velocity (MCA Vmean ). During supine rest, MAP (90 ± 13 versus 78 ± 9 mmHg; P<0·001) was elevated in the older subjects while their frontal lobe oxygenation (68 ± 7% versus 77 ± 7%; P<0·001), MCA Vmean (49 ± 9 versus 60 ± 12 cm s-1 ; P = 0·016) and CBF (754 ± 112 versus 900 ± 144 ml min-1 ; P = 0·004) were low reflected in VA (138 ± 48 versus 219 ± 50 ml min-1 ; P<0·001) rather than in ICA flow (616 ± 96 versus 680 ± 120 ml min-1 ; P = 0·099). In conclusion, blood supply to the brain and its oxygenation are affected by ageing and the age-related decline in VA flow appears to be four times as large as that in ICA and could be important for the age-related increase in MAP.
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Affiliation(s)
- Niels D Olesen
- Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henning B Nielsen
- Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Niels V Olsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Niels H Secher
- Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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13
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Wszedybyl-Winklewska M, Wolf J, Szarmach A, Winklewski PJ, Szurowska E, Narkiewicz K. Central sympathetic nervous system reinforcement in obstructive sleep apnoea. Sleep Med Rev 2018; 39:143-154. [DOI: 10.1016/j.smrv.2017.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 08/29/2017] [Accepted: 08/31/2017] [Indexed: 01/30/2023]
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14
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Moralez G, Jouett NP, Tian J, Zimmerman MC, Bhella P, Raven PB. Effect of centrally acting angiotensin converting enzyme inhibitor on the exercise-induced increases in muscle sympathetic nerve activity. J Physiol 2018; 596:2315-2332. [PMID: 29635787 PMCID: PMC6002210 DOI: 10.1113/jp274697] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 03/21/2018] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS The arterial baroreflex's operating point pressure is reset upwards and rightwards from rest in direct relation to the increases in dynamic exercise intensity. The intraneural pathways and signalling mechanisms that lead to upwards and rightwards resetting of the operating point pressure, and hence the increases in central sympathetic outflow during exercise, remain to be identified. We tested the hypothesis that the central production of angiotensin II during dynamic exercise mediates the increases in sympathetic outflow and, therefore, the arterial baroreflex operating point pressure resetting during acute and prolonged dynamic exercise. The results identify that perindopril, a centrally acting angiotensin converting enzyme inhibitor, markedly attenuates the central sympathetic outflow during acute and prolonged dynamic exercise. ABSTRACT We tested the hypothesis that the signalling mechanisms associated with the dynamic exercise intensity related increases in muscle sympathetic nerve activity (MSNA) and arterial baroreflex resetting during exercise are located within the central nervous system. Participants performed three randomly ordered trials of 70° upright back-supported dynamic leg cycling after ingestion of placebo and two different lipid soluble angiotensin converting enzyme inhibitors (ACEi): perindopril (high lipid solubility), captopril (low lipid solubility). Repeated measurements of whole venous blood (n = 8), MSNA (n = 7) and arterial blood pressures (n = 14) were obtained at rest and during an acute (SS1) and prolonged (SS2) bout of steady state dynamic exercise. Arterial baroreflex function curves were modelled at rest and during exercise. Peripheral venous superoxide concentrations measured by electron spin resonance spectroscopy were elevated during exercise and were not altered by ACEi at rest (P ≥ 0.4) or during exercise (P ≥ 0.3). Baseline MSNA and mean arterial pressure were unchanged at rest (P ≥ 0.1; P ≥ 0.8, respectively). However, during both SS1 and SS2, the centrally acting ACEi perindopril attenuated MSNA compared to captopril and the placebo (P < 0.05). Arterial pressures at the operating point and threshold pressures were decreased with perindopril from baseline to SS1 with no further changes in the operating point pressure during SS2 under all three conditions. These data suggest that centrally acting ACEi is significantly more effective at attenuating the increase in the acute and prolonged exercise-induced increases in MSNA.
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Affiliation(s)
- Gilbert Moralez
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical CenterDallasTXUSA
| | - Noah P. Jouett
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
| | - Jun Tian
- Department of Cellular and Integrative PhysiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Matthew C. Zimmerman
- Department of Cellular and Integrative PhysiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Paul Bhella
- Department of Cardiac Imaging at the John Peter Smith Health NetworkFort WorthTXUSA
- Department of Internal MedicineTCU and UNTHSC School of MedicineFort WorthTXUSA
| | - Peter B. Raven
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
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15
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Haspula D, Clark MA. Molecular Basis of the Brain Renin Angiotensin System in Cardiovascular and Neurologic Disorders: Uncovering a Key Role for the Astroglial Angiotensin Type 1 Receptor AT1R. J Pharmacol Exp Ther 2018; 366:251-264. [PMID: 29752427 DOI: 10.1124/jpet.118.248831] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
The central renin angiotensin system (RAS) is one of the most widely investigated cardiovascular systems in the brain. It is implicated in a myriad of cardiovascular diseases. However, studies from the last decade have identified its involvement in several neurologic abnormalities. Understanding the molecular functionality of the various RAS components can thus provide considerable insight into the phenotypic differences and mechanistic drivers of not just cardiovascular but also neurologic disorders. Since activation of one of its primary receptors, the angiotensin type 1 receptor (AT1R), results in an augmentation of oxidative stress and inflammatory cytokines, it becomes essential to investigate not just neuronal RAS but glial RAS as well. Glial cells are key homeostatic regulators in the brain and are critical players in the resolution of overt oxidative stress and neuroinflammation. Designing better and effective therapeutic strategies that target the brain RAS could well hinge on understanding the molecular basis of both neuronal and glial RAS. This review provides a comprehensive overview of the major studies that have investigated the mechanisms and regulation of the brain RAS, and it also provides insight into the potential role of glial AT1Rs in the pathophysiology of cardiovascular and neurologic disorders.
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Affiliation(s)
- Dhanush Haspula
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin (D.H.); and College of Pharmacy, Department of Pharmaceutical Sciences, Nova Southeastern University, Ft. Lauderdale, Florida (M.A.C.)
| | - Michelle A Clark
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin (D.H.); and College of Pharmacy, Department of Pharmaceutical Sciences, Nova Southeastern University, Ft. Lauderdale, Florida (M.A.C.)
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16
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Haspula D, Clark MA. Neuroinflammation and sympathetic overactivity: Mechanisms and implications in hypertension. Auton Neurosci 2018; 210:10-17. [DOI: 10.1016/j.autneu.2018.01.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 01/02/2018] [Accepted: 01/08/2018] [Indexed: 02/07/2023]
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17
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Onishi M, Yamanaka K, Miyamoto Y, Waki H, Gouraud S. Trpv4 involvement in the sex differences in blood pressure regulation in spontaneously hypertensive rats. Physiol Genomics 2018; 50:272-286. [PMID: 29373075 DOI: 10.1152/physiolgenomics.00096.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Arterial pressure (AP) is lower in premenopausal women than in men of a similar age. Premenopausal women exhibit a lower sympathetic activity and a greater baroreceptor reflex; however, mechanisms controlling sex differences in blood pressure regulation are not well understood. We hypothesized that different neuronal functions in the cardiovascular centers of the brains of men and women may contribute to the sex difference in cardiovascular homeostasis. Our previous studies on male spontaneously hypertensive rats (SHRs) and their normotensive counterparts, Wistar Kyoto (WKY) rats, revealed that the gene-expression profile of the nucleus tractus solitarius (NTS), a region of the medulla oblongata that is pivotal for regulating the set point of AP, is strongly associated with AP. Thus, we hypothesized that gene-expression profiles in the rat NTS are related to sex differences in AP regulation. Because female SHRs clearly exhibit lower AP than their male counterparts of a similar age, we investigated whether SHR NTS exhibits sex differences in gene expression by using microarray and RT-qPCR experiments. The transcript for transient receptor potential cation channel subfamily V member 4 ( Trpv4) was found to be upregulated in SHR NTS in females compared with that in males. The channel was expressed in neurons and glial cells within NTS. The TRPV4 agonist 4-alpha-phorbol-12,13-didecanoate (4α-PDD) decreased blood pressure when injected into NTS of rats. These findings suggest that altered TRPV4 expression might be involved in the sex differences in blood pressure regulation.
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Affiliation(s)
- Makiko Onishi
- Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo , Japan.,Institute for Human Life Innovation, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo , Japan
| | - Ko Yamanaka
- Department of Physiology, Graduate School of Health and Sports Science, Juntendo University, Inzai-city, Chiba , Japan
| | - Yasunori Miyamoto
- Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo , Japan.,Program for Leading Graduate Schools, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo , Japan.,Institute for Human Life Innovation, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo , Japan
| | - Hidefumi Waki
- Department of Physiology, Graduate School of Health and Sports Science, Juntendo University, Inzai-city, Chiba , Japan
| | - Sabine Gouraud
- Program for Leading Graduate Schools, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo , Japan.,Department of Biology, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo , Japan
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18
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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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19
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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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20
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Liu MY, Li N, Li WA, Khan H. Association between psychosocial stress and hypertension: a systematic review and meta-analysis. Neurol Res 2017; 39:573-580. [PMID: 28415916 DOI: 10.1080/01616412.2017.1317904] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Mei-Yan Liu
- Department of Cardiology, Anzhen Hospital, Capital Medical University, Beijing, China
| | - Na Li
- Department of Cardiology, Anzhen Hospital, Capital Medical University, Beijing, China
| | - William A. Li
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA
| | - Hajra Khan
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA
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21
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Marvar PJ, Hendy EB, Cruise TD, Walas D, DeCicco D, Vadigepalli R, Schwaber JS, Waki H, Murphy D, Paton JFR. Systemic leukotriene B 4 receptor antagonism lowers arterial blood pressure and improves autonomic function in the spontaneously hypertensive rat. J Physiol 2016; 594:5975-5989. [PMID: 27230966 DOI: 10.1113/jp272065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 05/09/2016] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS Evidence indicates an association between hypertension and chronic systemic inflammation in both human hypertension and experimental animal models. Previous studies in the spontaneously hypertensive rat (SHR) support a role for leukotriene B4 (LTB4 ), a potent chemoattractant involved in the inflammatory response, but its mode of action is poorly understood. In the SHR, we observed an increase in T cells and macrophages in the brainstem; in addition, gene expression profiling data showed that LTB4 production, degradation and downstream signalling in the brainstem of the SHR are dynamically regulated during hypertension. When LTB4 receptor 1 (BLT1) receptors were blocked with CP-105,696, arterial pressure was reduced in the SHR compared to the normotensive control and this reduction was associated with a significant decrease in systolic blood pressure (BP) indicators. These data provide new evidence for the role of LTB4 as an important neuro-immune pathway in the development of hypertension and therefore may serve as a novel therapeutic target for the treatment of neurogenic hypertension. ABSTRACT Accumulating evidence indicates an association between hypertension and chronic systemic inflammation in both human hypertension and experimental animal models. Previous studies in the spontaneously hypertensive rat (SHR) support a role for leukotriene B4 (LTB4 ), a potent chemoattractant involved in the inflammatory response. However, the mechanism for LTB4 -mediated inflammation in hypertension is poorly understood. Here we report in the SHR, increased brainstem infiltration of T cells and macrophages plus gene expression profiling data showing that LTB4 production, degradation and downstream signalling in the brainstem of the SHR are dynamically regulated during hypertension. Chronic blockade of the LTB4 receptor 1 (BLT1) receptor with CP-105,696, reduced arterial pressure in the SHR compared to the normotensive control and this reduction was associated with a significant decrease in low and high frequency spectra of systolic blood pressure, and an increase in spontaneous baroreceptor reflex gain (sBRG). These data provide new evidence for the role of LTB4 as an important neuro-immune pathway in the development of hypertension and therefore may serve as a novel therapeutic target for the treatment of neurogenic hypertension.
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Affiliation(s)
- Paul J Marvar
- Department of Pharmacology and Physiology Washington, The George Washington University School of Medical and Health Sciences, Washington, DC, USA
| | - Emma B Hendy
- School of Physiology, Pharmacology & Neuroscience, Medical Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Thomas D Cruise
- School of Physiology, Pharmacology & Neuroscience, Medical Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Dawid Walas
- School of Physiology, Pharmacology & Neuroscience, Medical Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Danielle DeCicco
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Rajanikanth Vadigepalli
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - James S Schwaber
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Hidefumi Waki
- Graduate School of Health and Sports Science, Juntendo University, Chiba, Japan
| | - David Murphy
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Dorothy Hodgkin Building, University of Bristol, Whitson Street, Bristol, BS1 3NY, UK
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Medical Sciences, University of Bristol, Bristol, BS8 1TD, UK.
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22
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Marina N, Teschemacher AG, Kasparov S, Gourine AV. Glia, sympathetic activity and cardiovascular disease. Exp Physiol 2016; 101:565-76. [PMID: 26988631 PMCID: PMC5031202 DOI: 10.1113/ep085713] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 03/10/2016] [Indexed: 12/13/2022]
Abstract
NEW FINDINGS What is the topic of this review? In this review, we discuss recent findings that provide a novel insight into the mechanisms that link glial cell function with the pathogenesis of cardiovascular disease, including systemic arterial hypertension and chronic heart failure. What advances does it highlight? We discuss how glial cells may influence central presympathetic circuits, leading to maladaptive and detrimental increases in sympathetic activity and contributing to the development and progression of cardiovascular disease. Increased activity of the sympathetic nervous system is associated with the development of cardiovascular disease and may contribute to its progression. Vasomotor and cardiac sympathetic activities are generated by the neuronal circuits located in the hypothalamus and the brainstem. These neuronal networks receive multiple inputs from the periphery and other parts of the CNS and, at a local level, may be influenced by their non-neuronal neighbours, in particular glial cells. In this review, we discuss recent experimental evidence suggesting that astrocytes and microglial cells are able to modulate the activity of sympathoexcitatory neural networks in disparate physiological and pathophysiological conditions. We focus on the chemosensory properties of astrocytes residing in the rostral ventrolateral medulla oblongata and discuss signalling mechanisms leading to glial activation during brain hypoxia and inflammation. Alterations in these mechanisms may lead to heightened activity of sympathoexcitatory CNS circuits and contribute to maladaptive and detrimental increases in sympathetic tone associated with systemic arterial hypertension and chronic heart failure.
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Affiliation(s)
- Nephtali Marina
- Department of Clinical Pharmacology, University College London, London, WC1E 6JF, UK
| | - Anja G Teschemacher
- School of Physiology and Pharmacology, Medical Sciences Building, Bristol Heart Institute, University of Bristol, Bristol, BS8 1TD, UK
| | - Sergey Kasparov
- School of Physiology and Pharmacology, Medical Sciences Building, Bristol Heart Institute, University of Bristol, Bristol, BS8 1TD, UK
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT, UK
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23
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Biancardi VC, Stern JE. Compromised blood-brain barrier permeability: novel mechanism by which circulating angiotensin II signals to sympathoexcitatory centres during hypertension. J Physiol 2016; 594:1591-600. [PMID: 26580484 PMCID: PMC4799983 DOI: 10.1113/jp271584] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 10/23/2015] [Indexed: 12/14/2022] Open
Abstract
Angiotensin II (AngII) is a pivotal peptide implicated in the regulation of blood pressure. In addition to its systemic vascular and renal effects, AngII acts centrally to modulate the activities of neuroendocrine and sympathetic neuronal networks, influencing in turn sympatho-humoral outflows to the circulation. Moreover, a large body of evidence supports AngII signalling dysregulation as a key mechanism contributing to exacerbated sympathoexcitation during hypertension. Due to its hydrophilic actions, circulating AngII does not cross the blood-brain barrier (BBB), signalling to the brain via the circumventricular organs which lack a tight BBB. In this review, we present and discuss recent studies from our laboratory showing that elevated circulating levels of AngII during hypertension result in disruption of the BBB integrity, allowing access of circulating AngII to critical sympathoexcitatory brain centres such as the paraventricular nucleus of the hypothalamus and the rostral ventrolateral medulla. We propose the novel hypothesis that AngII-driven BBB breakdown constitutes a complementary mechanism by which circulating AngII, working in tandem with the central renin-angiotensin system, further exacerbates sympatho-humoral activation during hypertension. These results are discussed within the context of a growing body of evidence in the literature supporting AngII as a pro-inflammatory signal, and brain microglia as key cell targets mediating central AngII actions during hypertension.
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Affiliation(s)
- V C Biancardi
- Department of Physiology, Georgia Regents University, Augusta, GA, USA
| | - J E Stern
- Department of Physiology, Georgia Regents University, Augusta, GA, USA
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24
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DeCicco D, Zhu H, Brureau A, Schwaber JS, Vadigepalli R. MicroRNA network changes in the brain stem underlie the development of hypertension. Physiol Genomics 2015; 47:388-99. [PMID: 26126791 DOI: 10.1152/physiolgenomics.00047.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 06/29/2015] [Indexed: 01/12/2023] Open
Abstract
Hypertension is a major chronic disease whose molecular mechanisms remain poorly understood. We compared neuroanatomical patterns of microRNAs in the brain stem of the spontaneous hypertensive rat (SHR) to the Wistar Kyoto rat (WKY, control). We quantified 419 well-annotated microRNAs in the nucleus of the solitary tract (NTS) and rostral ventrolateral medulla (RVLM), from SHR and WKY rats, during three main stages of hypertension development. Changes in microRNA expression were stage- and region-dependent, with a majority of SHR vs. WKY differential expression occurring at the hypertension onset stage in NTS versus at the prehypertension stage in RVLM. Our analysis identified 24 microRNAs showing time-dependent differential expression in SHR compared with WKY in at least one brain region. We predicted potential gene regulatory targets corresponding to catecholaminergic processes, neuroinflammation, and neuromodulation using the miRWALK and RNA22 databases, and we tested those bioinformatics predictions using high-throughput quantitative PCR to evaluate correlations of differential expression between the microRNAs and their predicted gene targets. We found a novel regulatory network motif consisting of microRNAs likely downregulating a negative regulator of prohypertensive processes such as angiotensin II signaling and leukotriene-based inflammation. Our results provide new evidence on the dynamics of microRNA expression in the development of hypertension and predictions of microRNA-mediated regulatory networks playing a region-dependent role in potentially altering brain-stem cardiovascular control circuit function leading to the development of hypertension.
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Affiliation(s)
- Danielle DeCicco
- Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Haisun Zhu
- Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Anthony Brureau
- Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - James S Schwaber
- Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Rajanikanth Vadigepalli
- Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics/Computational Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
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25
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Winklewski PJ, Radkowski M, Wszedybyl-Winklewska M, Demkow U. Brain inflammation and hypertension: the chicken or the egg? J Neuroinflammation 2015; 12:85. [PMID: 25935397 PMCID: PMC4432955 DOI: 10.1186/s12974-015-0306-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/23/2015] [Indexed: 12/24/2022] Open
Abstract
Inflammation of forebrain and hindbrain nuclei controlling the sympathetic nervous system (SNS) outflow from the brain to the periphery represents an emerging concept of the pathogenesis of neurogenic hypertension. Angiotensin II (Ang-II) and prorenin were shown to increase production of reactive oxygen species and pro-inflammatory cytokines (interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)) while simultaneously decreasing production of interleukin-10 (IL-10) in the paraventricular nucleus of the hypothalamus and the rostral ventral lateral medulla. Peripheral chronic inflammation and Ang-II activity seem to share a common central mechanism contributing to an increase in sympathetic neurogenic vasomotor tone and entailing neurogenic hypertension. Both hypertension and obesity facilitate the penetration of peripheral immune cells in the brain parenchyma. We suggest that renin-angiotensin-driven hypertension encompasses feedback and feedforward mechanisms in the development of neurogenic hypertension while low-intensity, chronic peripheral inflammation of any origin may serve as a model of a feedforward mechanism in this condition.
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Affiliation(s)
- Pawel J Winklewski
- Institute of Human Physiology, Medical University of Gdansk, Tuwima Str. 15, 80-210, Gdansk, Poland.
| | - Marek Radkowski
- Department of Immunopathology of Infectious and Parasitic Diseases, Medical University of Warsaw, Pawinskiego Str. 3c, 02-106, Warsaw, Poland.
| | | | - Urszula Demkow
- Department of Laboratory Diagnostics and Clinical Immunology of Developmental Age, Medical University of Warsaw, Marszalkowska Str. 24, 00-576, Warsaw, Poland.
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26
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Hay M. His and hers hypertension-down to a T? Am J Physiol Renal Physiol 2015; 308:F822-3. [PMID: 25587126 DOI: 10.1152/ajprenal.00667.2014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Meredith Hay
- Department of Physiology, Evelyn F. McKnight Brain Institute, Saver Heart Center, University of Arizona, Tucson, Arizona
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27
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Marina N, Ang R, Machhada A, Kasymov V, Karagiannis A, Hosford PS, Mosienko V, Teschemacher AG, Vihko P, Paton JFR, Kasparov S, Gourine AV. Brainstem hypoxia contributes to the development of hypertension in the spontaneously hypertensive rat. Hypertension 2015; 65:775-83. [PMID: 25712724 PMCID: PMC4354460 DOI: 10.1161/hypertensionaha.114.04683] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 02/02/2015] [Indexed: 02/07/2023]
Abstract
Systemic arterial hypertension has been previously suggested to develop as a compensatory condition when central nervous perfusion/oxygenation is compromised. Principal sympathoexcitatory C1 neurons of the rostral ventrolateral medulla oblongata (whose activation increases sympathetic drive and the arterial blood pressure) are highly sensitive to hypoxia, but the mechanisms of this O2 sensitivity remain unknown. Here, we investigated potential mechanisms linking brainstem hypoxia and high systemic arterial blood pressure in the spontaneously hypertensive rat. Brainstem parenchymal PO2 in the spontaneously hypertensive rat was found to be ≈15 mm Hg lower than in the normotensive Wistar rat at the same level of arterial oxygenation and systemic arterial blood pressure. Hypoxia-induced activation of rostral ventrolateral medulla oblongata neurons was suppressed in the presence of either an ATP receptor antagonist MRS2179 or a glycogenolysis inhibitor 1,4-dideoxy-1,4-imino-d-arabinitol, suggesting that sensitivity of these neurons to low PO2 is mediated by actions of extracellular ATP and lactate. Brainstem hypoxia triggers release of lactate and ATP which produce excitation of C1 neurons in vitro and increases sympathetic nerve activity and arterial blood pressure in vivo. Facilitated breakdown of extracellular ATP in the rostral ventrolateral medulla oblongata by virally-driven overexpression of a potent ectonucleotidase transmembrane prostatic acid phosphatase results in a significant reduction in the arterial blood pressure in the spontaneously hypertensive rats (but not in normotensive animals). These results suggest that in the spontaneously hypertensive rat, lower PO2 of brainstem parenchyma may be associated with higher levels of ambient ATP and l-lactate within the presympathetic circuits, leading to increased central sympathetic drive and concomitant sustained increases in systemic arterial blood pressure.
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Affiliation(s)
- Nephtali Marina
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.).
| | - Richard Ang
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Asif Machhada
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Vitaliy Kasymov
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Anastassios Karagiannis
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Patrick S Hosford
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Valentina Mosienko
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Anja G Teschemacher
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Pirkko Vihko
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Julian F R Paton
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Sergey Kasparov
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.)
| | - Alexander V Gourine
- From the Centre for Cardiovascular and Metabolic Neuroscience (N.M., R.A., A.M., V.K., A.K., P.S.H., A.V.G.), Department of Clinical Pharmacology and Experimental Therapeutics (N.M., P.S.H.), and Neuroscience, Physiology and Pharmacology (R.A., A.M., V.K., A.K., A.V.G.), University College London, London, United Kingdom; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (V.M., A.G.T., J.F.R.P., S.K.); and Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland (P.V.).
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Sandberg K, Ji H, Hay M. Sex-specific immune modulation of primary hypertension. Cell Immunol 2014; 294:95-101. [PMID: 25498375 DOI: 10.1016/j.cellimm.2014.12.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 11/28/2014] [Accepted: 12/01/2014] [Indexed: 01/11/2023]
Abstract
It is well known that the onset of essential hypertension occurs earlier in men than women. Numerous studies have shown sex differences in the vasculature, kidney and sympathetic nervous system contribute to this sex difference in the development of hypertension. The immune system also contributes to the development of hypertension; however, sex differences in immune system modulation of blood pressure (BP) and the development of hypertension has only recently begun to be explored. Here we review findings on the effect of one's sex on the immune system and specifically how these effects impact BP and the development of primary hypertension. We also propose a hypothesis for why mechanisms underlying inflammation-induced hypertension are sex-specific. These studies underscore the value of and need for studying both sexes in the basic science exploration of the pathophysiology of hypertension as well as other diseases.
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Affiliation(s)
- Kathryn Sandberg
- Department of Medicine and Center for the Study of Sex Differences in Health, Aging and Disease, Suite 232 Bldg D., Georgetown University, Washington D.C. 20057, United States
| | - Hong Ji
- Department of Medicine and Center for the Study of Sex Differences in Health, Aging and Disease, Suite 232 Bldg D., Georgetown University, Washington D.C. 20057, United States
| | - Meredith Hay
- Department of Physiology and the Evelyn F. McKnight Brain Institute, University of Arizona, 1503 N. Campbell Rd, Bldg 201, Room 4103, Tucson, AZ 85724, United States.
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29
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Pechanova O, Paulis L, Simko F. Peripheral and central effects of melatonin on blood pressure regulation. Int J Mol Sci 2014; 15:17920-37. [PMID: 25299692 PMCID: PMC4227197 DOI: 10.3390/ijms151017920] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/17/2014] [Accepted: 09/17/2014] [Indexed: 01/01/2023] Open
Abstract
The pineal hormone, melatonin (N-acetyl-5-methoxytryptamine), shows potent receptor-dependent and -independent actions, which participate in blood pressure regulation. The antihypertensive effect of melatonin was demonstrated in experimental and clinical hypertension. Receptor-dependent effects are mediated predominantly through MT1 and MT2 G-protein coupled receptors. The pleiotropic receptor-independent effects of melatonin with a possible impact on blood pressure involve the reactive oxygen species (ROS) scavenging nature, activation and over-expression of several antioxidant enzymes or their protection from oxidative damage and the ability to increase the efficiency of the mitochondrial electron transport chain. Besides the interaction with the vascular system, this indolamine may exert part of its antihypertensive action through its interaction with the central nervous system (CNS). The imbalance between the sympathetic and parasympathetic vegetative system is an important pathophysiological disorder and therapeutic target in hypertension. Melatonin is protective in CNS on several different levels: It reduces free radical burden, improves endothelial dysfunction, reduces inflammation and shifts the balance between the sympathetic and parasympathetic system in favor of the parasympathetic system. The increased level of serum melatonin observed in some types of hypertension may be a counter-regulatory adaptive mechanism against the sympathetic overstimulation. Since melatonin acts favorably on different levels of hypertension, including organ protection and with minimal side effects, it could become regularly involved in the struggle against this widespread cardiovascular pathology.
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Affiliation(s)
- Olga Pechanova
- Institute of Normal and Pathological Physiology and Centre of Excellence for Nitric Oxide Research, Slovak Academy of Sciences, Bratislava 81371, Slovak Republic.
| | - Ludovit Paulis
- Institute of Normal and Pathological Physiology and Centre of Excellence for Nitric Oxide Research, Slovak Academy of Sciences, Bratislava 81371, Slovak Republic.
| | - Fedor Simko
- Department of Pathophysiology, Faculty of Medicine, Comenius University, Bratislava 81371, Slovak Republic.
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30
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Sato K, Yamashita T, Kurata T, Fukui Y, Hishikawa N, Deguchi K, Abe K. Telmisartan ameliorates inflammatory responses in SHR-SR after tMCAO. J Stroke Cerebrovasc Dis 2014; 23:2511-2519. [PMID: 25245484 DOI: 10.1016/j.jstrokecerebrovasdis.2014.02.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 11/29/2022] Open
Abstract
Telmisartan, an angiotensin receptor blocker with high lipid solubility, also called metabo-sartan, not only reduces blood pressure (BP), but also ameliorates inflammation in the cerebral cortex and in adipose tissue. We examined the effects of telmisartan on inflammatory responses of monocyte chemotactic protein-1, tumor necrosis factor-α, and ionized calcium-binding adapter molecule 1 in the brain of spontaneously hypertensive rat stroke-resistant (SHR-SR) after transient middle cerebral artery occlusion (tMCAO). At 12 weeks of age, SHR-SR received tMCAO for 90 minutes and were divided into 3 groups, that is, the vehicle group, a low-dose telmisartan group (.3 mg/kg/day), and a high-dose telmisartan group (3 mg/kg/day). Immunohistological analysis was performed when rats became 6, 12 and 18 months old. Monocyte chemotactic protein-1, tumor necrosis factor-α, and ionized calcium-binding adapter molecule 1 cells (/mm(2)) immunoreactivities increased with age in the cerebral cortex and hippocampus of the vehicle group, suggesting strong and persistent inflammatory changes in SHR-SR after tMCAO up to 18 months of age. On the other hand, a low dose of telmisartan significantly reduced such inflammatory changes without lowering BP, whereas a high dose of telmisartan showed a few additional improvements, including the lowering of BP throughout 6-18 months of age. The present study suggests that persistent hypertension after tMCAO caused a long-lasting inflammatory response in the SHR-SR brain, and that even a low dose of telmisartan reduced continuous inflammation without lowering BP via its pleiotropic effects in the SHR-SR brain. A high dose of telmisartan had a few additional benefits, including lowering BP.
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Affiliation(s)
- Kota Sato
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Toru Yamashita
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Tomoko Kurata
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Yusuke Fukui
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Nozomi Hishikawa
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Kentaro Deguchi
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Koji Abe
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
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31
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Barnes JN, Charkoudian N, Matzek LJ, Johnson CP, Joyner MJ, Curry TB. Acute cyclooxygenase inhibition does not alter muscle sympathetic nerve activity or forearm vasodilator responsiveness in lean and obese adults. Physiol Rep 2014; 2:2/7/e12079. [PMID: 25347862 PMCID: PMC4187568 DOI: 10.14814/phy2.12079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Obesity is often characterized by chronic inflammation that may contribute to increased cardiovascular risk via sympathoexcitation and decreased vasodilator responsiveness. We hypothesized that obese individuals would have greater indices of inflammation compared with lean controls, and that cyclooxygenase inhibition using ibuprofen would reduce muscle sympathetic nerve activity (MSNA) and increase forearm blood flow in these subjects. We measured MSNA, inflammatory biomarkers (C‐reactive protein [CRP] and Interleukin‐6 [IL‐6]), and forearm vasodilator responses to brachial artery acetylcholine and sodium nitroprusside in 13 men and women (7 lean; 6 obese) on two separate study days: control (CON) and after 800 mg ibuprofen (IBU). CRP (1.7 ± 0.4 vs. 0.6 ± 0.3 mg/L; P < 0.05) and IL‐6 (4.1 ± 1.5 vs. 1.0 ± 0.1pg/mL; P < 0.05) were higher in the obese group during CON and tended to decrease with IBU (IL‐6: P < 0.05; CRP: P = 0.14). MSNA was not different between groups during CON (26 ± 4 bursts/100 heart beats (lean) versus 26 ± 4 bursts/100 heart beats (obese); P = 0.50) or IBU (25 ± 4 bursts/100 heart beats (lean) versus 30 ± 5 bursts/100 heart beats (obese); P = 0.25), and was not altered by IBU. Forearm vasodilator responses were unaffected by IBU in both groups. In summary, an acute dose of ibuprofen did not alter sympathetic nerve activity or forearm blood flow responses in healthy obese individuals, suggesting that the cyclooxygenase pathway is not a major contributor to these variables in this group. Obesity is often characterized by chronic inflammation that may contribute to increased cardiovascular risk via sympathoexcitation. However, an acute dose of the cyclooxygenase inhibitor ibuprofen did not alter blood pressure or muscle sympathetic nerve activity in lean and obese humans.
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Affiliation(s)
- Jill N Barnes
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Luke J Matzek
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
| | | | | | - Timothy B Curry
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
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32
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Pollow DP, Uhrlaub J, Romero-Aleshire M, Sandberg K, Nikolich-Zugich J, Brooks HL, Hay M. Sex differences in T-lymphocyte tissue infiltration and development of angiotensin II hypertension. Hypertension 2014; 64:384-390. [PMID: 24890822 DOI: 10.1161/hypertensionaha.114.03581] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
There is extensive evidence that activation of the immune system is both necessary and required for the development of angiotensin II (Ang II)-induced hypertension in males. The purpose of this study was to determine whether sex differences exist in the ability of the adaptive immune system to induce Ang II-dependent hypertension and whether central and renal T-cell infiltration during Ang II-induced hypertension is sex dependent. Recombinant activating gene-1 (Rag-1)(-/-) mice, lacking both T and B cells, were used. Male and female Rag-1(-/-) mice received adoptive transfer of male CD3(+) T cells 3 weeks before 14-day Ang II infusion (490 ng/kg per minute). Blood pressure was monitored via tail cuff. In the absence of T cells, systolic blood pressure responses to Ang II were similar between sexes (Δ22.1 mm Hg males versus Δ18 mm : Hg females). After adoptive transfer of male T cells, Ang II significantly increased systolic blood pressure in males (Δ37.7 mm : Hg; P<0.05) when compared with females (Δ13.7 mm : Hg). Flow cytometric analysis of total T cells and CD4(+), CD8(+), and regulatory Foxp3(+)-CD4(+) T-cell subsets identified that renal lymphocyte infiltration was significantly increased in males versus females in both control and Ang II-infused animals (P<0.05). Immunohistochemical staining for CD3(+)-positive T cells in the subfornical organ region of the brain was increased in males when compared with that in females. These results suggest that female Rag-1(-/-) mice are protected from male T-cell-mediated increases in Ang II-induced hypertension when compared with their male counterparts, and this protection may involve sex differences in the magnitude of T-cell infiltration of the kidney and brain.
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Affiliation(s)
- Dennis P Pollow
- Department of Physiology University of Arizona, Tucson, AZ.,Sarver Heart Center University of Arizona, Tucson, AZ
| | | | | | - Kathryn Sandberg
- Department of Medicine and Center for the Study of Sex Differences in Health, Aging and Disease, Georgetown University, Washington, DC
| | | | - Heddwen L Brooks
- Department of Physiology University of Arizona, Tucson, AZ.,Sarver Heart Center University of Arizona, Tucson, AZ
| | - Meredith Hay
- Department of Physiology University of Arizona, Tucson, AZ.,Sarver Heart Center University of Arizona, Tucson, AZ.,Evelyn McKnight Brain Institute, University of Arizona, Tucson, AZ
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33
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Raven PB, Chapleau MW. Blood pressure regulation XI: overview and future research directions. Eur J Appl Physiol 2014; 114:579-86. [PMID: 24463603 PMCID: PMC3955090 DOI: 10.1007/s00421-014-2823-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 01/09/2014] [Indexed: 10/25/2022]
Abstract
While the importance of regulating arterial blood pressure within a 'normal' range is widely appreciated, the definition of 'normal' and the means by which humans and other species regulate blood pressure under various conditions remain hotly debated. The effects of diverse physiological, pathological and environmental challenges on blood pressure and the mechanisms that attempt to maintain it at an optimal level are reviewed and critically analyzed in a series of articles published in this themed issue of the European Journal of Applied Physiology. We summarize here the major points made in these reviews, with emphasis on unifying concepts of regulatory mechanisms and future directions for research.
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Affiliation(s)
- Peter B Raven
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA,
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34
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Waki H, Gouraud SS. Brain inflammation in neurogenic hypertension. World J Hypertens 2014; 4:1-6. [DOI: 10.5494/wjh.v4.i1.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 11/14/2013] [Accepted: 12/13/2013] [Indexed: 02/06/2023] Open
Abstract
One likely mechanism of essential hypertension (EH) is increased sympathoexcitation due to abnormal functions in the cardiovascular center of the brain. Recent findings obtained using experimental animal models of EH have shown that abnormal inflammation in the cardiovascular center may contribute to the onset of hypertension. Inflammatory molecules such as cytokines and reactive oxygen species released from the inflamed vasculature and glial cells in the medulla oblongata and hypothalamus might directly or indirectly affect neuronal functions. This in turn could increase sympathetic nerve activity and consequently arterial pressure. Abnormal inflammatory responses in the brain could also be central mechanisms underlying angiotensin II-related EH. In this review, we present the current understanding of EH mechanisms with regard to inflammatory responses in the cardiovascular center.
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35
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McGinnis WR, Audhya T, Edelson SM. Proposed toxic and hypoxic impairment of a brainstem locus in autism. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:6955-7000. [PMID: 24336025 PMCID: PMC3881151 DOI: 10.3390/ijerph10126955] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/07/2013] [Accepted: 11/11/2013] [Indexed: 01/15/2023]
Abstract
Electrophysiological findings implicate site-specific impairment of the nucleus tractus solitarius (NTS) in autism. This invites hypothetical consideration of a large role for this small brainstem structure as the basis for seemingly disjointed behavioral and somatic features of autism. The NTS is the brain's point of entry for visceral afference, its relay for vagal reflexes, and its integration center for autonomic control of circulatory, immunological, gastrointestinal, and laryngeal function. The NTS facilitates normal cerebrovascular perfusion, and is the seminal point for an ascending noradrenergic system that modulates many complex behaviors. Microvascular configuration predisposes the NTS to focal hypoxia. A subregion--the "pNTS"--permits exposure to all blood-borne neurotoxins, including those that do not readily transit the blood-brain barrier. Impairment of acetylcholinesterase (mercury and cadmium cations, nitrates/nitrites, organophosphates, monosodium glutamate), competition for hemoglobin (carbon monoxide, nitrates/nitrites), and higher blood viscosity (net systemic oxidative stress) are suggested to potentiate microcirculatory insufficiency of the NTS, and thus autism.
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Affiliation(s)
- Woody R. McGinnis
- Autism Research Institute, 4182 Adams Avenue, San Diego, CA 92116, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-541-326-8822; Fax: +1-619-563-6840
| | - Tapan Audhya
- Division of Endocrinology, Department of Medicine, New York University Medical School, New York, NY 10016, USA; E-Mail:
| | - Stephen M. Edelson
- Autism Research Institute, 4182 Adams Avenue, San Diego, CA 92116, USA; E-Mail:
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36
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Ruchaya PJ, Antunes VR, Paton JFR, Murphy D, Yao ST. The cardiovascular actions of fractalkine/CX3CL1 in the hypothalamic paraventricular nucleus are attenuated in rats with heart failure. Exp Physiol 2013; 99:111-22. [DOI: 10.1113/expphysiol.2013.075432] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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37
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Xie F, Fu H, Hou JF, Jiao K, Costigan M, Chen J. High energy diets-induced metabolic and prediabetic painful polyneuropathy in rats. PLoS One 2013; 8:e57427. [PMID: 23451227 PMCID: PMC3581455 DOI: 10.1371/journal.pone.0057427] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 01/22/2013] [Indexed: 12/16/2022] Open
Abstract
To establish the role of the metabolic state in the pathogenesis of polyneuropathy, an age- and sex-matched, longitudinal study in rats fed high-fat and high-sucrose diets (HFSD) or high-fat, high-sucrose and high-salt diets (HFSSD) relative to controls was performed. Time courses of body weight, systolic blood pressure, fasting plasma glucose (FPG), insulin, free fatty acids (FFA), homeostasis model assessment-insulin resistance index (HOMA-IR), thermal and mechanical sensitivity and motor coordination were measured in parallel. Finally, large and small myelinated fibers (LMF, SMF) as well as unmyelinated fibers (UMF) in the sciatic nerves and ascending fibers in the spinal dorsal column were quantitatively assessed under electron microscopy. The results showed that early metabolic syndrome (hyperinsulinemia, dyslipidemia, and hypertension) and prediabetic conditions (impaired fasting glucose) could be induced by high energy diet, and these animals later developed painful polyneuropathy characterized by myelin breakdown and LMF loss in both peripheral and central nervous system. In contrast SMF and UMF in the sciatic nerves were changed little, in the same animals. Therefore the phenomenon that high energy diets induce bilateral mechanical, but not thermal, pain hypersensitivity is reflected by severe damage to LMF, but mild damage to SMF and UMF. Moreover, dietary sodium (high-salt) deteriorates the neuropathic pathological process induced by high energy diets, but paradoxically high salt consumption, may reduce, at least temporarily, chronic pain perception in these animals.
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Affiliation(s)
- Fang Xie
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, P. R. China
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Hypertension-induced peripheral neuropathy and the combined effects of hypertension and diabetes on nerve structure and function in rats. Acta Neuropathol 2012; 124:561-73. [PMID: 22791295 DOI: 10.1007/s00401-012-1012-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 06/26/2012] [Accepted: 06/29/2012] [Indexed: 01/02/2023]
Abstract
Diabetic neuropathy includes damage to neurons, Schwann cells and blood vessels. Rodent models of diabetes do not adequately replicate all pathological features of diabetic neuropathy, particularly Schwann cell damage. We, therefore, tested the hypothesis that combining hypertension, a risk factor for neuropathy in diabetic patients, with insulin-deficient diabetes produces a more pertinent model of peripheral neuropathy. Behavioral, physiological and structural indices of neuropathy were measured for up to 6 months in spontaneously hypertensive and age-matched normotensive rats with or without concurrent streptozotocin-induced diabetes. Hypertensive rats developed nerve ischemia, thermal hyperalgesia, nerve conduction slowing and axonal atrophy. Thinly myelinated fibers with supernumerary Schwann cells indicative of cycles of demyelination and remyelination were also identified along with reduced nerve levels of myelin basic protein. Similar disorders were noted in streptozotocin-diabetic rats, except that thinly myelinated fibers were not observed and expression of myelin basic protein was normal. Superimposing diabetes on hypertension compounded disorders of nerve blood flow, conduction slowing and axonal atrophy and increased the incidence of thinly myelinated fibers. Rats with combined insulinopenia, hyperglycemia and hypertension provide a model for diabetic neuropathy that offers an opportunity to study mechanisms of Schwann cell pathology and suggests that hypertension may contribute to the etiology of diabetic neuropathy.
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Wu KLH, Chan SHH, Chan JYH. Neuroinflammation and oxidative stress in rostral ventrolateral medulla contribute to neurogenic hypertension induced by systemic inflammation. J Neuroinflammation 2012; 9:212. [PMID: 22958438 PMCID: PMC3462714 DOI: 10.1186/1742-2094-9-212] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Accepted: 08/27/2012] [Indexed: 02/07/2023] Open
Abstract
Background In addition to systemic inflammation, neuroinflammation in the brain, which enhances sympathetic drive, plays a significant role in cardiovascular diseases, including hypertension. Oxidative stress in rostral ventrolateral medulla (RVLM) that augments sympathetic outflow to blood vessels is involved in neural mechanism of hypertension. We investigated whether neuroinflammation and oxidative stress in RVLM contribute to hypertension following chronic systemic inflammation. Methods In normotensive Sprague-Dawley rats, systemic inflammation was induced by infusion of Escherichia coli lipopolysaccharide (LPS) into the peritoneal cavity via an osmotic minipump. Systemic arterial pressure and heart rate were measured under conscious conditions by the non-invasive tail-cuff method. The level of the inflammatory markers in plasma or RVLM was analyzed by ELISA. Protein expression was evaluated by Western blot or immunohistochemistry. Tissue level of superoxide anion (O2·-) in RVLM was determined using the oxidation-sensitive fluorescent probe dihydroethidium. Pharmacological agents were delivered either via infusion into the cisterna magna with an osmotic minipump or microinjection bilaterally into RVLM. Results Intraperitoneal infusion of LPS (1.2 mg/kg/day) for 14 days promoted sustained hypertension and induced a significant increase in plasma level of C-reactive protein, tumor necrosis factor-α (TNF-α), or interleukin-1β (IL-1β). This LPS-induced systemic inflammation was accompanied by activation of microglia, augmentation of IL-1β, IL-6, or TNF-α protein expression, and O2·- production in RVLM, all of which were blunted by intracisternal infusion of a cycloxygenase-2 (COX-2) inhibitor, NS398; an inhibitor of microglial activation, minocycline; or a cytokine synthesis inhibitor, pentoxifylline. Neuroinflammation in RVLM was also associated with a COX-2-dependent downregulation of endothelial nitric oxide synthase and an upregulation of intercellular adhesion molecule-1. Finally, the LPS-promoted long-term pressor response and the reduction in expression of voltage-gated potassium channel, Kv4.3 in RVLM were antagonized by minocycline, NS398, pentoxifylline, or a superoxide dismutase mimetic, tempol, either infused into cisterna magna or microinjected bilaterally into RVLM. The same treatments, on the other hand, were ineffective against LPS-induced systemic inflammation. Conclusion These results suggest that systemic inflammation activates microglia in RVLM to induce COX-2-dependent neuroinflammation that leads to an increase in O2·- production. The resultant oxidative stress in RVLM in turn mediates neurogenic hypertension.
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Affiliation(s)
- Kay L H Wu
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, 83301, Taiwan
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Marvar PJ, Harrison DG. Stress-dependent hypertension and the role of T lymphocytes. Exp Physiol 2012; 97:1161-7. [PMID: 22941978 DOI: 10.1113/expphysiol.2011.061507] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hypertension is a significant global health burden that is associated with an increased risk of stroke, atherosclerosis and other cardiovascular diseases. Several risk factors, including high dietary salt, obesity, genetics and race, as well as behavioural and psychological factors, contribute to development of this complex disease. Various hypertensive stimuli enhance sympathetic drive and promote autonomic dysfunction leading to elevated blood pressure. As our understanding of the pathogenesis and end-organ damage associated with hypertension increases, mounting evidence also highlights the role of inflammation in this process and, in particular, the role of the adaptive immune system and T cells. This review discusses recent findings regarding the role of the central nervous system, T lymphocytes and the impact of cardiovascular risk factors, such as psychological stress, in hypertension.
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Affiliation(s)
- Paul J Marvar
- Department of Psychiatry, Emory University School of Medicine, Atlanta, GA, USA.
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Quintessential Risk Factors: Their Role in Promoting Cognitive Dysfunction and Alzheimer’s Disease. Neurochem Res 2012; 37:2627-58. [DOI: 10.1007/s11064-012-0854-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 07/21/2012] [Indexed: 12/13/2022]
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A cardiovascular role for fractalkine and its cognate receptor, CX3CR1, in the rat nucleus of the solitary tract. Neuroscience 2012; 209:119-27. [DOI: 10.1016/j.neuroscience.2012.02.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/09/2012] [Accepted: 02/09/2012] [Indexed: 01/07/2023]
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Pathogenesis of cognitive dysfunction in patients with obstructive sleep apnea: a hypothesis with emphasis on the nucleus tractus solitarius. SLEEP DISORDERS 2012; 2012:251096. [PMID: 23470865 PMCID: PMC3581091 DOI: 10.1155/2012/251096] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/13/2011] [Accepted: 12/22/2011] [Indexed: 02/06/2023]
Abstract
OSA is characterized by the quintessential triad of intermittent apnea, hypoxia, and hypoxemia due to pharyngeal collapse. This paper highlights the upstream mechanisms that may trigger cognitive decline in OSA. Three interrelated steps underpin cognitive dysfunction in OSA patients. First, several risk factors upregulate peripheral inflammation; these crucial factors promote neuroinflammation, cerebrovascular endothelial dysfunction, and oxidative stress in OSA. Secondly, the neuroinflammation exerts negative impact globally on the CNS, and thirdly, important foci in the neocortex and brainstem are rendered inflamed and dysfunctional. A strong link is known to exist between neuroinflammation and neurodegeneration. A unique perspective delineated here underscores the importance of dysfunctional brainstem nuclei in etiopathogenesis of cognitive decline in OSA patients. Nucleus tractus solitarius (NTS) is the central integration hub for afferents from upper airway (somatosensory/gustatory), respiratory, gastrointestinal, cardiovascular (baroreceptor and chemoreceptor) and other systems. The NTS has an essential role in sympathetic and parasympathetic systems also; it projects to most key brain regions and modulates numerous physiological functions. Inflamed and dysfunctional NTS and other key brainstem nuclei may play a pivotal role in triggering memory and cognitive dysfunction in OSA. Attenuation of upstream factors and amelioration of the NTS dysfunction remain important challenges.
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Dysfunctional nucleus tractus solitarius: its crucial role in promoting neuropathogenetic cascade of Alzheimer's dementia--a novel hypothesis. Neurochem Res 2012; 37:846-68. [PMID: 22219130 DOI: 10.1007/s11064-011-0680-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/16/2011] [Accepted: 12/15/2011] [Indexed: 12/22/2022]
Abstract
The pathophysiological mechanism(s) underlying Alzheimer's disease (AD) still remain unclear, and no disease-modifying or prophylactic therapies are currently available. Unraveling the fundamental neuropathogenesis of AD is an important challenge. Several studies on AD have suggested lesions in a number of CNS areas including the basal forebrain, hippocampus, entorhinal cortex, amygdale/insula, and the locus coeruleus. However, plausible unifying studies on the upstream factors that involve these heterogeneous regions and herald the onset of AD pathogenesis are not available. The current article presents a novel nucleus tractus solitarius (NTS) vector hypothesis that underpins several disparate biological mechanisms and neural circuits, and identifies relevant hallmarks of major presumptive causative factor(s) linked to the NTS, in older/aging individuals. Aging, obesity, infection, sleep apnea, smoking, neuropsychological states, and hypothermia-all activate inflammatory cytokines and oxidative stress. The synergistic impact of systemic proinflammatory mediators activates microglia and promotes neuroinflammation. Acutely, the innate immune response is protective defending against pathogens/toxins; however, when chronic, it causes neuroinflammation and neuronal dysfunction, particularly in brainstem and neocortex. The NTS in the brainstem is an essential multiple signaling hub, and an extremely important central integration site of baroreceptor, chemoreceptor, and a multitude of sensory afferents from gustatory, gastrointestinal, cardiac, pulmonary, and upper airway systems. Owing to persistent neuroinflammation, the dysfunctional NTS exerts deleterious impact on nucleus ambiguus, dorsal motor nucleus of vagus, hypoglossal, parabrachial, locus coeruleus and many key nuclei in the brainstem, and the hippocampus, entorhinal cortex, prefrontal cortex, amygdala, insula, and basal forebrain in the neocortex. The neuronal and synaptic dysfunction emanating from the inflamed NTS may affect its interconnected pathways impacting almost the entire CNS--which is already primed by neuroinflammation, thus promoting cognitive and neuropsychiatric symptoms. The upstream factors discussed here may underpin the neuropathopgenesis of AD. AD pathology is multifactorial; the current perspective underscores the value of attenuating disparate upstream factors--in conjunction with anticholinesterase, anti-inflammatory, immunosuppressive, and anti-oxidant pharmacotherapy. Amelioration of the NTS pathology may be of central importance in countering the neuropathological cascade of AD. The NTS, therefore, may be a potential target of novel therapeutic strategies.
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Marques FZ, Campain AE, Davern PJ, Yang YHJ, Head GA, Morris BJ. Global identification of the genes and pathways differentially expressed in hypothalamus in early and established neurogenic hypertension. Physiol Genomics 2011; 43:766-71. [DOI: 10.1152/physiolgenomics.00009.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The hypothalamus has an important etiological role in the onset and maintenance of hypertension and stress responses in the Schlager high blood pressure (BP) (BPH/2J) mouse, a genetic model of neurogenic hypertension. Using Affymetrix GeneChip Mouse Gene 1.0 ST Arrays we identified 1,019 hypothalamic genes whose expression differed between 6 wk old BPH/2J and normal BP (BPN/3J) strains, and 466 for 26 wk old mice. Of these, 459 were in 21 mouse BP quantitative trait loci. We validated 46 genes by qPCR. Gene changes that would increase sympathetic outflow at both ages were: Dynll1 encoding dynein light chain LC8-type 1, which physically destabilizes neuronal nitric oxide synthase, decreasing neuronal nitric oxide, and Hcrt encoding hypocretin and Npsr1 encoding neuropeptide S receptor 1, each involved in sympathetic response to stress. At both ages we identified genes for inflammation, such as CC-chemokine ligand 19 ( Ccl19), and oxidative stress. Via reactive oxygen species generation, these could contribute to oxidative damage. Other genes identified could be responding to such perturbations. Atp2b1, the major gene from genome-wide association studies of BP variation, was underexpressed in the early phase. Comparison of profiles of young and adult BPH/2J mice, after adjusting for maturation genes, pointed to the proopiomelanocortin-α gene ( Pomc) and neuropeptide Y gene ( Npy), among others, as potentially causative. The present study has identified a diversity of genes and possible mechanisms involved in hypertension etiology and maintenance in the hypothalamus of BPH/2J mice, highlighting both common and divergent processes in each phase of the condition.
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Affiliation(s)
- Francine Z. Marques
- Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, and
| | - Anna E. Campain
- School of Mathematics and Statistics, The University of Sydney, Sydney, New South Wales; and
| | - Pamela J. Davern
- the Neuropharmacology Laboratory, Baker IDI Heart Research Institute, Melbourne, Victoria, Australia
| | - Yee Hwa J. Yang
- School of Mathematics and Statistics, The University of Sydney, Sydney, New South Wales; and
| | - Geoffrey A. Head
- the Neuropharmacology Laboratory, Baker IDI Heart Research Institute, Melbourne, Victoria, Australia
| | - Brian J. Morris
- Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, and
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The central nervous system and inflammation in hypertension. Curr Opin Pharmacol 2010; 11:156-61. [PMID: 21196131 DOI: 10.1016/j.coph.2010.12.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 11/30/2010] [Accepted: 12/06/2010] [Indexed: 02/07/2023]
Abstract
In recent years a major research effort has focused on the role of inflammation, and in particular adaptive immunity, in the genesis of hypertension. Hypertension stimulates the accumulation of inflammatory cells including macrophages and T lymphocytes in peripheral tissues important in blood pressure control, such as the kidney and vasculature. Angiotensin II modulates blood pressure via actions on the central nervous system (CNS) and the adaptive immune system. Recent work suggests that the central actions of angiotensin II via the circumventricular organs lead to activation of circulating T-cells and vascular inflammation. The neuro-immune system plays an essential role in the pathogenesis of hypertension and further understanding of this relationship could lead to the development of new treatment strategies.
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Cifuentes RA, Cruz-Tapias P, Rojas-Villarraga A, Anaya JM. ZC3H12A (MCPIP1): molecular characteristics and clinical implications. Clin Chim Acta 2010; 411:1862-8. [PMID: 20807520 DOI: 10.1016/j.cca.2010.08.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 08/22/2010] [Accepted: 08/24/2010] [Indexed: 12/15/2022]
Abstract
BACKGROUND ZC3H12A is a gene whose absence is related to autoimmune disorders and to other phenotypical alterations. METHODS A comprehensive review of the structure, molecular functions and regulation of ZC3H12A gene and its protein MCPIP1 is done in order to understand their clinical implications. RESULTS ZC3H12A, at 1p34.3, has 9860bp, six exons and 61 described SNPs. Eleven are non-synonymous thus leading to changes in MCPIP1, the protein encoded by ZC3H12A. MCPIP1 is induced by MCP-1 and IL-1 whose signals are transduced through the NF-kβ and MAPkinase pathways. This protein acts as an RNAse by degrading chemokine transcripts such as IL-1 as well as its own mRNA and as a transcription factor by reducing the expression of other chemokines induced by NF-kβ such as MCP-1. It also up-regulates genes involved in several differentiation processes and apoptosis. Therefore, ZC3H12A is an equilibrium gatekeeper that not only regulates its own inducers but also controls the regulation by degrading its own mRNA. CONCLUSION Understanding ZC3H12A gives a comprehensive panorama that promises to improve our understanding of processes in which this gene is involved including autoimmune, infectious and cardiovascular diseases.
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Affiliation(s)
- Ricardo A Cifuentes
- Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia
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Joyner MJ, Charkoudian N, Wallin BG. Sympathetic nervous system and blood pressure in humans: individualized patterns of regulation and their implications. Hypertension 2010; 56:10-6. [PMID: 20497993 DOI: 10.1161/hypertensionaha.109.140186] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Michael J Joyner
- Department of Anesthesiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
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Grassi G, Seravalle G, Quarti-Trevano F. The 'neuroadrenergic hypothesis' in hypertension: current evidence. Exp Physiol 2009; 95:581-6. [PMID: 20008032 DOI: 10.1113/expphysiol.2009.047381] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Data collected in experimental animals and in humans support the hypothesis that sympathetic neural mechanisms are involved in the development and progression of hypertension. Direct approaches to assess human adrenergic cardiovascular drive have shown that sympathetic activation occurs in hypertensive patients, the magnitude of which is proportional to the degree of elevation of the blood pressure. Evidence has also been obtained that sympathetic activation participates in the development of hypertension-related target organ damage, such as left ventricular diastolic dysfunction, left ventricular hypertrophy and arterial remodelling and hypertrophy. Despite the large amount of information collected on the main features of the hypertension-related neurogenic abnormality, the causes of the sympathetic activation remain undefined, although alterations in the reflex modulation of adrenergic drive and/or participation of metabolic factors are likely candidates. This paper will provide background information on the behaviour of the sympathetic nervous system in experimental hypertension, followed by a review of the main features, mechanisms and effects of the sympathetic overdrive in human hypertension. Finally, the new frontiers of research in the area of therapeutic intervention aimed at reducing the adrenergic overdrive will be highlighted.
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Affiliation(s)
- Guido Grassi
- Clinica Medica, Ospedale S. Gerardo dei Tintori, Via Pergolesi 33, 20052 Monza, Milan, Italy.
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Sun C, Zubcevic J, Polson JW, Potts JT, Diez-Freire C, Zhang Q, Paton JFR, Raizada MK. Shift to an involvement of phosphatidylinositol 3-kinase in angiotensin II actions on nucleus tractus solitarii neurons of the spontaneously hypertensive rat. Circ Res 2009; 105:1248-55. [PMID: 19850939 DOI: 10.1161/circresaha.109.208926] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Central angiotensin (Ang) II inhibits baroreflex and plays an important role in the pathogenesis of hypertension. However, the underlying molecular mechanisms are still not fully understood. OBJECTIVE Our objective in the present study was to characterize the signal transduction mechanism of phosphatidylinositol 3-kinase (PI3K) involvement in Ang II-induced stimulation of central neuronal activity in cultured neurons and Ang II-induced inhibition of baroreflex in spontaneously hypertensive rats (SHR) versus WKY rats. METHODS AND RESULTS Application of Ang II to neurons produced a 42% greater increase in neuronal firing in cells from the SHR than the WKY rat. Although the Ang II-mediated increase in firing rate was abolished entirely by the protein kinase (PK)C inhibitor GF109230 in the WKY, blockade of both PKC and PI3K activity was necessary in the SHR. This was associated with an increased ability of Ang II to stimulate NADPH oxidase-reactive oxygen species (ROS)-mediated signaling involving phosphorylation of the p47phox subunit of the NADPH oxidase and was dependent on the activation of PI3K in the SHR. Inhibition of PI3K resulted in the reduction of levels of p47phox phosphorylation, NADPH oxidase activity, ROS levels, and ultimately neuronal activity in cells from the SHR but not the WKY rat. In addition, in working heart-brainstem preparations, inhibition of PKC activity in the nucleus of the solitary tract in situ abolished the Ang II-mediated depression of cardiac and sympathetic baroreceptor reflex gain in the WKY. In contrast, PKC inhibition in the nucleus of the solitary tract of SHR only partially reduced the effect of Ang II on the baroreceptor reflex gain. CONCLUSIONS These observations demonstrate that PI3K in the cardiovascular brainstem regions of the SHR may be selectively involved in Ang II-mediated signaling that includes a reduction in baroreceptor reflex function, presumably via a NADPH-ROS mediated pathway.
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Affiliation(s)
- Chengwen Sun
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32610, USA
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