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Romano A, Friuli M, Eramo B, Gallelli CA, Koczwara JB, Azari EK, Paquot A, Arnold M, Langhans W, Muccioli GG, Lutz TA, Gaetani S. "To brain or not to brain": evaluating the possible direct effects of the satiety factor oleoylethanolamide in the central nervous system. Front Endocrinol (Lausanne) 2023; 14:1158287. [PMID: 37234803 PMCID: PMC10206109 DOI: 10.3389/fendo.2023.1158287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/12/2023] [Indexed: 05/28/2023] Open
Abstract
Introduction Oleoylethanolamide (OEA), an endogenous N-acylethanolamine acting as a gut-to-brain signal to control food intake and metabolism, has been attracting attention as a target for novel therapies against obesity and eating disorders. Numerous observations suggested that the OEA effects might be peripherally mediated, although they involve central pathways including noradrenergic, histaminergic and oxytocinergic systems of the brainstem and the hypothalamus. Whether these pathways are activated directly by OEA or whether they are downstream of afferent nerves is still highly debated. Some early studies suggested vagal afferent fibers as the main route, but our previous observations have contradicted this idea and led us to consider the blood circulation as an alternative way for OEA's central actions. Methods To test this hypothesis, we first investigated the impact of subdiaphragmatic vagal deafferentation (SDA) on the OEA-induced activation of selected brain nuclei. Then, we analyzed the pattern of OEA distribution in plasma and brain at different time points after intraperitoneal administration in addition to measuring food intake. Results Confirming and extending our previous findings that subdiaphragmatic vagal afferents are not necessary for the eating-inhibitory effect of exogenous OEA, our present results demonstrate that vagal sensory fibers are also not necessary for the neurochemical effects of OEA. Rather, within a few minutes after intraperitoneal administration, we found an increased concentration of intact OEA in different brain areas, associated with the inhibition of food intake. Conclusion Our results support that systemic OEA rapidly reaches the brain via the circulation and inhibits eating by acting directly on selected brain nuclei.
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Affiliation(s)
- Adele Romano
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, Rome, Italy
| | - Marzia Friuli
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, Rome, Italy
| | - Barbara Eramo
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, Rome, Italy
| | - Cristina Anna Gallelli
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, Rome, Italy
| | - Justyna Barbara Koczwara
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, Rome, Italy
| | | | - Adrien Paquot
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, UCLouvain, Brussels, Belgium
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, ETH Zurich, Zurich, Switzerland
| | | | - Giulio G. Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, UCLouvain, Brussels, Belgium
| | - Thomas Alexander Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Silvana Gaetani
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, Rome, Italy
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Tacke C, Bischoff AM, Harb A, Vafadari B, Hülsmann S. Angiotensin II increases respiratory rhythmic activity in the preBötzinger complex without inducing astroglial calcium signaling. Front Cell Neurosci 2023; 17:1111263. [PMID: 36816850 PMCID: PMC9932970 DOI: 10.3389/fncel.2023.1111263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Angiotensin II (Ang II) is the primary modulator of the renin-angiotensin system and has been widely studied for its effect on the cardiovascular system. While a few studies have also indicated an involvement of Ang II in the regulation of breathing, very little is known in this regard and its effect on brainstem respiratory regions such as the preBötzinger complex (preBötC), the kernel for inspiratory rhythm generation, has not been investigated yet. This study reports that Ang II temporarily increases phrenic nerve activity in the working heart-brainstem preparation, indicating higher central respiratory drive. Previous studies have shown that the carotid body is involved in mediating this effect and we revealed that the preBötC also plays a part, using acute slices of the brainstem. It appears that Ang II is increasing the respiratory drive in an AT1R-dependent manner by optimizing the interaction of inhibitory and excitatory neurons of the preBötC. Thus, Ang II-mediated effects on the preBötC are potentially involved in dysregulating breathing in patients with acute lung injury.
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Méndez-García LA, Escobedo G, Minguer-Uribe AG, Viurcos-Sanabria R, Aguayo-Guerrero JA, Carrillo-Ruiz JD, Solleiro-Villavicencio H. Role of the renin-angiotensin system in the development of COVID-19-associated neurological manifestations. Front Cell Neurosci 2022; 16:977039. [PMID: 36187294 PMCID: PMC9523599 DOI: 10.3389/fncel.2022.977039] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/26/2022] [Indexed: 01/18/2023] Open
Abstract
SARS-CoV-2 causes COVID-19, which has claimed millions of lives. This virus can infect various cells and tissues, including the brain, for which numerous neurological symptoms have been reported, ranging from mild and non-life-threatening (e.g., headaches, anosmia, dysgeusia, and disorientation) to severe and life-threatening symptoms (e.g., meningitis, ischemic stroke, and cerebral thrombosis). The cellular receptor for SARS-CoV-2 is angiotensin-converting enzyme 2 (ACE2), an enzyme that belongs to the renin-angiotensin system (RAS). RAS is an endocrine system that has been classically associated with regulating blood pressure and fluid and electrolyte balance; however, it is also involved in promoting inflammation, proliferation, fibrogenesis, and lipogenesis. Two pathways constitute the RAS with counter-balancing effects, which is the key to its regulation. The first axis (classical) is composed of angiotensin-converting enzyme (ACE), angiotensin (Ang) II, and angiotensin type 1 receptor (AT1R) as the main effector, which -when activated- increases the production of aldosterone and antidiuretic hormone, sympathetic nervous system tone, blood pressure, vasoconstriction, fibrosis, inflammation, and reactive oxygen species (ROS) production. Both systemic and local classical RAS' within the brain are associated with cognitive impairment, cell death, and inflammation. The second axis (non-classical or alternative) includes ACE2, which converts Ang II to Ang-(1-7), a peptide molecule that activates Mas receptor (MasR) in charge of opposing Ang II/AT1R actions. Thus, the alternative RAS axis enhances cognition, synaptic remodeling, cell survival, cell signal transmission, and antioxidant/anti-inflammatory mechanisms in the brain. In a physiological state, both RAS axes remain balanced. However, some factors can dysregulate systemic and local RAS arms. The binding of SARS-CoV-2 to ACE2 causes the internalization and degradation of this enzyme, reducing its activity, and disrupting the balance of systemic and local RAS, which partially explain the appearance of some of the neurological symptoms associated with COVID-19. Therefore, this review aims to analyze the role of RAS in the development of the neurological effects due to SARS-CoV-2 infection. Moreover, we will discuss the RAS-molecular targets that could be used for therapeutic purposes to treat the short and long-term neurological COVID-19-related sequelae.
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Affiliation(s)
- Lucía A. Méndez-García
- Laboratory of Immunometabolism, Research Division, General Hospital of Mexico “Dr. Eduardo Liceaga,”Mexico City, Mexico
| | - Galileo Escobedo
- Laboratory of Immunometabolism, Research Division, General Hospital of Mexico “Dr. Eduardo Liceaga,”Mexico City, Mexico
| | - Alan Gerardo Minguer-Uribe
- Laboratory of Molecular Neuropathology, Cellular Physiology Institute, National Autonomous University of Mexico, Mexico City, Mexico
| | - Rebeca Viurcos-Sanabria
- Laboratory of Immunometabolism, Research Division, General Hospital of Mexico “Dr. Eduardo Liceaga,”Mexico City, Mexico
- PECEM, School of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - José A. Aguayo-Guerrero
- Laboratory of Immunometabolism, Research Division, General Hospital of Mexico “Dr. Eduardo Liceaga,”Mexico City, Mexico
| | - José Damián Carrillo-Ruiz
- Research Directorate, General Hospital of Mexico “Dr. Eduardo Liceaga,”Mexico City, Mexico
- Department of Neurology and Neurosurgery, General Hospital of Mexico “Dr. Eduardo Liceaga,”Mexico City, Mexico
- Facultad de Ciencias de la Salud, Universidad Anáhuac, Huixquilucan, Mexico
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Zmira O, Gofrit SG, Aharoni SA, Weiss R, Shavit-Stein E, Chapman J. Teriflunomide normalizes anti-anxiety effect in anti-ANXA2 APS mice model teriflunomide in anti-ANXA2 mice model. Lupus 2022; 31:855-863. [PMID: 35575144 DOI: 10.1177/09612033221095150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Antiphospholipid syndrome (APS) affects the brain by both hypercoagulation and immunological mechanisms. APS is characterized by several autoantibodies binding to a thrombolytic complex including beta-2-glycoprotein I (β2-GPI) and annexin A2 (ANXA2). Teriflunomide, an oral drug for the treatment of multiple sclerosis (MS), has a cytostatic effect on B cells and is therefore a potential antibody-targeting treatment for APS. In this study, we assessed the effect of teriflunomide in two APS mouse models by inducing autoantibody formation against β2-GPI and ANXA2 in female BALB/c mice. The ANXA2 model displayed a behavioral change suggesting an anti-anxiety effect in open field and forced swim tests, early in the course of the disease. This effect was normalized following teriflunomide treatment. Conversely, behavioral tests done later during the study demonstrated depression-like behavior in the ANXA2 model. No behavioral changes were seen in the β2-GPI model. Total brain IgG levels were significantly elevated in the ANXA2 model but not in the teriflunomide treated group. No such change was noted in the brains of the β2-GPI model. High levels of serum autoantibodies were induced in both models, and their levels were not lowered by teriflunomide treatment. Teriflunomide ameliorated behavioral changes in mice immunized with ANXA2 without a concomitant change in serum antibody levels. These findings are compatible with the effect of teriflunomide on neuroinflammation.Teriflunomide ameliorated behavioral and brain IgG levels in mice immunized with ANXA2 without a concomitant change in serum antibody levels. These findings are compatible with an effect of teriflunomide on the IgG permeability to the brain and neuroinflammation.
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Affiliation(s)
- Ofir Zmira
- Department of Neurology, 26744Sheba Medical Center, Ramat Gan, Israel.,Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shany Guly Gofrit
- Department of Neurology, 26744Sheba Medical Center, Ramat Gan, Israel
| | - Shay Anat Aharoni
- Department of Neurology, 26744Sheba Medical Center, Ramat Gan, Israel
| | - Ronen Weiss
- Department of Neurology, 26744Sheba Medical Center, Ramat Gan, Israel.,Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Joseph Sagol Neuroscience Center, 26744Sheba Medical Center, Tel HaShomer, Israel
| | - Efrat Shavit-Stein
- Department of Neurology, 26744Sheba Medical Center, Ramat Gan, Israel.,Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Joseph Sagol Neuroscience Center, 26744Sheba Medical Center, Tel HaShomer, Israel.,The TELEM Rubin Excellence in Biomedical Research Program, The Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Joab Chapman
- Department of Neurology, 26744Sheba Medical Center, Ramat Gan, Israel.,Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Joseph Sagol Neuroscience Center, 26744Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Robert and Martha Harden Chair in Mental and Neurological Diseases, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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5
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Bian M, Chen L, Lei L. Research progress on the relationship between chronic periodontitis and Parkinson's disease. Zhejiang Da Xue Xue Bao Yi Xue Ban 2022; 51:108-114. [PMID: 35462470 PMCID: PMC9109767 DOI: 10.3724/zdxbyxb-2021-0111] [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: 10/24/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Chronic periodontitis is an infectious disease, which has a reciprocal relationship with a variety of systemic disorders. Parkinson's disease is a prevalent neurodegenerative disease in which inflammation plays an important role for its progression. A vast number of studies suggest that there is a potential connection between chronic periodontitis and neurodegenerative diseases such as Parkinson's disease. Individuals with Parkinson's disease usually have poor periodontal health, and their oral flora composition differs from that of healthy people; at the same time, patients with chronic periodontitis have a higher risk of Parkinson's disease, which can be reduced with regular periodontal treatment. In fact, the mechanism of interaction between chronic periodontitis and Parkinson's disease is not clear. According to several studies, the clinical symptoms of Parkinson's disease prevent patients to maintain oral hygiene effectively, increasing the risk of periodontitis. Neuroinflammation mediated by microglia may be the key to the influence of chronic periodontitis on Parkinson's disease. Periodontal pathogens and inflammatory mediators may enter the brain and activate microglia in various ways, and ultimately leading to occurrence and development of Parkinson's disease. This article reviews the recent research progress on the association between chronic periodontitis and Parkinson's disease, and its potential mechanism to provide information for further research.
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6
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Myers MG, Affinati AH, Richardson N, Schwartz MW. Central nervous system regulation of organismal energy and glucose homeostasis. Nat Metab 2021; 3:737-750. [PMID: 34158655 DOI: 10.1038/s42255-021-00408-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/12/2021] [Indexed: 02/05/2023]
Abstract
Growing evidence implicates the brain in the regulation of both immediate fuel availability (for example, circulating glucose) and long-term energy stores (that is, adipose tissue mass). Rather than viewing the adipose tissue and glucose control systems separately, we suggest that the brain systems that control them are components of a larger, highly integrated, 'fuel homeostasis' control system. This conceptual framework, along with new insights into the organization and function of distinct neuronal systems, provides a context within which to understand how metabolic homeostasis is achieved in both basal and postprandial states. We also review evidence that dysfunction of the central fuel homeostasis system contributes to the close association between obesity and type 2 diabetes, with the goal of identifying more effective treatment options for these common metabolic disorders.
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Affiliation(s)
- Martin G Myers
- Departments of Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Alison H Affinati
- Departments of Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Nicole Richardson
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Michael W Schwartz
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA, USA.
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7
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Clyburn C, Browning KN. Glutamatergic plasticity within neurocircuits of the dorsal vagal complex and the regulation of gastric functions. Am J Physiol Gastrointest Liver Physiol 2021; 320:G880-G887. [PMID: 33730858 PMCID: PMC8202199 DOI: 10.1152/ajpgi.00014.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The meticulous regulation of the gastrointestinal (GI) tract is required for the coordination of gastric motility and emptying, intestinal secretion, absorption, and transit as well as for the overarching management of food intake and energy homeostasis. Disruption of GI functions is associated with the development of severe GI disorders and the alteration of food intake and caloric balance. Functional GI disorders as well as the dysregulation of energy balance and food intake are frequently associated with, or result from, alterations in the central regulation of GI control. The faithful and rapid transmission of information from the stomach and upper GI tract to second-order neurons of the nucleus of the tractus solitarius (NTS) relies on the delicate modulation of excitatory glutamatergic transmission, as does the relay of integrated signals from the NTS to parasympathetic efferent neurons of the dorsal motor nucleus of the vagus (DMV). Many studies have focused on understanding the physiological and pathophysiological modulation of these glutamatergic synapses, although their role in the control and regulation of GI functions has lagged behind that of cardiovascular and respiratory functions. The purpose of this review is to examine the current literature exploring the role of glutamatergic transmission in the DVC in the regulation of GI functions.
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Affiliation(s)
- Courtney Clyburn
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Kirsteen N. Browning
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, Pennsylvania
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8
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Montégut L, Lopez-Otin C, Magnan C, Kroemer G. Old Paradoxes and New Opportunities for Appetite Control in Obesity. Trends Endocrinol Metab 2021; 32:264-294. [PMID: 33707095 DOI: 10.1016/j.tem.2021.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 12/13/2022]
Abstract
Human obesity is accompanied by alterations in the blood concentrations of multiple circulating appetite regulators. Paradoxically, most of the appetite-inhibitory hormones are elevated in nonsyndromic obesity, while most of the appetite stimulatory hormones are reduced, perhaps reflecting vain attempts of regulation by inefficient feedback circuitries. In this context, it is important to understand which appetite regulators exhibit a convergent rather than paradoxical behavior and hence are likely to contribute to the maintenance of the obese state. Pharmacological interventions in obesity should preferentially consist of the supplementation of deficient appetite inhibitors or the neutralization of excessive appetite stimulators. Here, we critically analyze the current literature on appetite-regulatory peptide hormones. We propose a short-list of appetite modulators that may constitute the best candidates for therapeutic interventions.
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Affiliation(s)
- Léa Montégut
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue Contre le Cancer, Université de Paris, Sorbonne Université, INSERM U1138, Institut Universitaire de France, Paris, France; Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France
| | - Carlos Lopez-Otin
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo, 33006, Oviedo, Spain
| | | | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue Contre le Cancer, Université de Paris, Sorbonne Université, INSERM U1138, Institut Universitaire de France, Paris, France; Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France; Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR8251, Université Paris Diderot, Paris, France; Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-, HP, Paris, France; Suzhou Institute for Systems Medicine, Chinese Academy of Medical Sciences, Suzhou, China; Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital, Stockholm, Sweden.
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9
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High B, Hixon AM, Tyler KL, Piquet AL, Pelak VS. Neurology and the COVID-19 Pandemic: Gathering Data for an Informed Response. Neurol Clin Pract 2021; 11:e48-e63. [PMID: 33842072 PMCID: PMC8032425 DOI: 10.1212/cpj.0000000000000908] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/18/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW The current coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the greatest medical crises faced by our current generation of health care providers. Although much remains to be learned about the pathophysiology of SARS-CoV-2, there is both historical precedent from other coronaviruses and a growing number of case reports and series that point to neurologic consequences of COVID-19. RECENT FINDINGS Olfactory/taste disturbances and increased risk of strokes and encephalopathies have emerged as potential consequences of COVID-19 infection. Evidence regarding whether these sequelae result indirectly from systemic infection or directly from neuroinvasion by SARS-CoV-2 is emerging. SUMMARY This review summarizes the current understanding of SARS-CoV-2 placed in context with our knowledge of other human coronaviruses. Evidence and data regarding neurologic sequelae of COVID-19 and the neuroinvasive potential of human coronaviruses are provided along with a summary of patient registries of interest to the Neurology community.
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Affiliation(s)
- Brigit High
- Medical Scientist Training Program (BH, AMH), Rocky Mountain Taste and Smell Center (BH), Department of Neurology (KLT, ALP, VSP), and Department of Ophthalmology (VSP), University of Colorado School of Medicine, Aurora
| | - Alison M Hixon
- Medical Scientist Training Program (BH, AMH), Rocky Mountain Taste and Smell Center (BH), Department of Neurology (KLT, ALP, VSP), and Department of Ophthalmology (VSP), University of Colorado School of Medicine, Aurora
| | - Kenneth L Tyler
- Medical Scientist Training Program (BH, AMH), Rocky Mountain Taste and Smell Center (BH), Department of Neurology (KLT, ALP, VSP), and Department of Ophthalmology (VSP), University of Colorado School of Medicine, Aurora
| | - Amanda L Piquet
- Medical Scientist Training Program (BH, AMH), Rocky Mountain Taste and Smell Center (BH), Department of Neurology (KLT, ALP, VSP), and Department of Ophthalmology (VSP), University of Colorado School of Medicine, Aurora
| | - Victoria S Pelak
- Medical Scientist Training Program (BH, AMH), Rocky Mountain Taste and Smell Center (BH), Department of Neurology (KLT, ALP, VSP), and Department of Ophthalmology (VSP), University of Colorado School of Medicine, Aurora
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10
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Aghayari Sheikh Neshin S, Shahjouei S, Koza E, Friedenberg I, Khodadadi F, Sabra M, Kobeissy F, Ansari S, Tsivgoulis G, Li J, Abedi V, Wolk DM, Zand R. Stroke in SARS-CoV-2 Infection: A Pictorial Overview of the Pathoetiology. Front Cardiovasc Med 2021; 8:649922. [PMID: 33855053 PMCID: PMC8039152 DOI: 10.3389/fcvm.2021.649922] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/01/2021] [Indexed: 12/15/2022] Open
Abstract
Since the early days of the pandemic, there have been several reports of cerebrovascular complications during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Numerous studies proposed a role for SARS-CoV-2 in igniting stroke. In this review, we focused on the pathoetiology of stroke among the infected patients. We pictured the results of the SARS-CoV-2 invasion to the central nervous system (CNS) via neuronal and hematogenous routes, in addition to viral infection in peripheral tissues with extensive crosstalk with the CNS. SARS-CoV-2 infection results in pro-inflammatory cytokine and chemokine release and activation of the immune system, COVID-19-associated coagulopathy, endotheliitis and vasculitis, hypoxia, imbalance in the renin-angiotensin system, and cardiovascular complications that all may lead to the incidence of stroke. Critically ill patients, those with pre-existing comorbidities and patients taking certain medications, such as drugs with elevated risk for arrhythmia or thrombophilia, are more susceptible to a stroke after SARS-CoV-2 infection. By providing a pictorial narrative review, we illustrated these associations in detail to broaden the scope of our understanding of stroke in SARS-CoV-2-infected patients. We also discussed the role of antiplatelets and anticoagulants for stroke prevention and the need for a personalized approach among patients with SARS-CoV-2 infection.
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Affiliation(s)
| | - Shima Shahjouei
- Neurology Department, Neuroscience Institute, Geisinger Health System, Danville, PA, United States
| | - Eric Koza
- Geisinger Commonwealth School of Medicine, Scranton, PA, United States
| | - Isabel Friedenberg
- Department of Biology, Pennsylvania State University, State College, PA, United States
| | | | - Mirna Sabra
- Neurosciences Research Center (NRC), Lebanese University/Medical School, Beirut, Lebanon
| | - Firas Kobeissy
- Program of Neurotrauma, Neuroproteomics and Biomarker Research (NNBR), University of Florida, Gainesville, FL, United States
| | - Saeed Ansari
- National Institute of Neurological Disorders and Stroke, National Institute of Health, Bethesda, MD, United States
| | - Georgios Tsivgoulis
- Second Department of Neurology, School of Medicine, "Attikon" University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Jiang Li
- Department of Molecular and Functional Genomics, Geisinger Health System, Danville, PA, United States
| | - Vida Abedi
- Department of Molecular and Functional Genomics, Geisinger Health System, Danville, PA, United States.,Biocomplexity Institute, Virginia Tech, Blacksburg, VA, United States
| | - Donna M Wolk
- Molecular and Microbial Diagnostics and Development, Diagnostic Medicine Institute, Laboratory Medicine, Geisinger Health System, Danville, PA, United States
| | - Ramin Zand
- Neurology Department, Neuroscience Institute, Geisinger Health System, Danville, PA, United States
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11
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Browning KN, Carson KE. Central Neurocircuits Regulating Food Intake in Response to Gut Inputs-Preclinical Evidence. Nutrients 2021; 13:nu13030908. [PMID: 33799575 PMCID: PMC7998662 DOI: 10.3390/nu13030908] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/02/2021] [Accepted: 03/07/2021] [Indexed: 02/07/2023] Open
Abstract
The regulation of energy balance requires the complex integration of homeostatic and hedonic pathways, but sensory inputs from the gastrointestinal (GI) tract are increasingly recognized as playing critical roles. The stomach and small intestine relay sensory information to the central nervous system (CNS) via the sensory afferent vagus nerve. This vast volume of complex sensory information is received by neurons of the nucleus of the tractus solitarius (NTS) and is integrated with responses to circulating factors as well as descending inputs from the brainstem, midbrain, and forebrain nuclei involved in autonomic regulation. The integrated signal is relayed to the adjacent dorsal motor nucleus of the vagus (DMV), which supplies the motor output response via the efferent vagus nerve to regulate and modulate gastric motility, tone, secretion, and emptying, as well as intestinal motility and transit; the precise coordination of these responses is essential for the control of meal size, meal termination, and nutrient absorption. The interconnectivity of the NTS implies that many other CNS areas are capable of modulating vagal efferent output, emphasized by the many CNS disorders associated with dysregulated GI functions including feeding. This review will summarize the role of major CNS centers to gut-related inputs in the regulation of gastric function with specific reference to the regulation of food intake.
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12
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Sinen O, Bülbül M. The role of autonomic pathways in peripheral apelin-induced gastrointestinal dysmotility: involvement of the circumventricular organs. Exp Physiol 2020; 106:475-485. [PMID: 33347671 DOI: 10.1113/ep089182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/07/2020] [Indexed: 01/19/2023]
Abstract
NEW FINDINGS What is the central question of this study? Are central autonomic pathways and circumventricular organs involved in apelin-induced inhibition of gut motility? What is the main finding and its importance? Peripherally administered apelin-13 inhibits gastric and colonic motor functions through sympathetic and parasympathetic autonomic pathways, which seems to be partly mediated by the apelin receptor in circumventricular organs. ABSTRACT Peripheral administration of apelin-13 has been shown to inhibit gastrointestinal (GI) motility, but the relevant mechanisms are incompletely understood. This study aimed to investigate (i) whether the apelin receptor (APJ) is expressed in circumventricular structures involved in autonomic functions, (ii) whether they are activated by peripherally administered apelin, (iii) the role of autonomic pathways in peripheral exogenous apelin-induced GI dysmotility, and (iv) the changes in apelin levels in the extracellular environment of the brain following its peripheral application. Ninety minutes after apelin-13 administration (300 μg kg-1 , i.p.), gastric emptying (GE) and colon transit (CT) were measured in rats that underwent parasympathectomy and/or sympathectomy. Plasma and cerebrospinal fluid (CSF) samples were also collected from another group of rats that received apelin-13 or vehicle injection. The immunoreactivities for APJ and c-Fos in circumventricular organs (CVOs) were evaluated by immunohistochemistry. Compared with vehicle-treated rats, GE and CT were inhibited significantly by apelin-13 treatment, and were completely restored in animals that underwent the combination of parasympathectomy and sympathectomy and sympathectomy alone, respectively. Apelin concentrations were elevated in both plasma and CSF following peripheral administration of apelin-13. APJ expression was detected in area postrema (AP), subfornical organ and organum vasculosum of lamina terminalis, and c-Fos expression was observed in response to apelin injection. Apelin-induced c-Fos expression in AP was partially attenuated by pretreatment with the cholecystokinin-1 receptor antagonist lorglumide, whereas it was completely abolished in vagotomized rats. The present data suggest that APJ in CVOs could indirectly contribute to the inhibitory action of peripheral apelin on GI motor functions.
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Affiliation(s)
- Osman Sinen
- Faculty of Medicine, Department of Physiology, Akdeniz University, Antalya, Turkey
| | - Mehmet Bülbül
- Faculty of Medicine, Department of Physiology, Akdeniz University, Antalya, Turkey
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13
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Cornejo MP, Mustafá ER, Barrile F, Cassano D, De Francesco PN, Raingo J, Perello M. THE INTRIGUING LIGAND-DEPENDENT AND LIGAND-INDEPENDENT ACTIONS OF THE GROWTH HORMONE SECRETAGOGUE RECEPTOR ON REWARD-RELATED BEHAVIORS. Neurosci Biobehav Rev 2020; 120:401-416. [PMID: 33157147 DOI: 10.1016/j.neubiorev.2020.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/18/2020] [Accepted: 10/20/2020] [Indexed: 02/07/2023]
Abstract
The growth hormone secretagogue receptor (GHSR) is a G-protein-coupled receptor (GPCR) highly expressed in the brain, and also in some peripheral tissues. GHSR activity is evoked by the stomach-derived peptide hormone ghrelin and abrogated by the intestine-derived liver-expressed antimicrobial peptide 2 (LEAP2). In vitro, GHSR displays ligand-independent actions, including a high constitutive activity and an allosteric modulation of other GPCRs. Beyond its neuroendocrine and metabolic effects, cumulative evidence shows that GHSR regulates the activity of the mesocorticolimbic pathway and modulates complex reward-related behaviors towards different stimuli. Here, we review current evidence indicating that ligand-dependent and ligand-independent actions of GHSR enhance reward-related behaviors towards appetitive stimuli and drugs of abuse. We discuss putative neuronal networks and molecular mechanisms that GHSR would engage to modulate such reward-related behaviors. Finally, we briefly discuss imaging studies showing that ghrelin would also regulate reward processing in humans. Overall, we conclude that GHSR is a key regulator of the mesocorticolimbic pathway that influences its activity and, consequently, modulates reward-related behaviors via ligand-dependent and ligand-independent actions.
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Affiliation(s)
- María P Cornejo
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina
| | - Emilio R Mustafá
- Laboratory of Electrophysiology of the IMBICE, 1900 La Plata, Buenos Aires, Argentina
| | - Franco Barrile
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina
| | - Daniela Cassano
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina
| | - Pablo N De Francesco
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina
| | - Jesica Raingo
- Laboratory of Electrophysiology of the IMBICE, 1900 La Plata, Buenos Aires, Argentina
| | - Mario Perello
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina.
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14
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Divani AA, Andalib S, Di Napoli M, Lattanzi S, Hussain MS, Biller J, McCullough LD, Azarpazhooh MR, Seletska A, Mayer SA, Torbey M. Coronavirus Disease 2019 and Stroke: Clinical Manifestations and Pathophysiological Insights. J Stroke Cerebrovasc Dis 2020; 29:104941. [PMID: 32689643 PMCID: PMC7214348 DOI: 10.1016/j.jstrokecerebrovasdis.2020.104941] [Citation(s) in RCA: 141] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023] Open
Abstract
Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Some COVID-19 patients have exhibited widespread neurological manifestations including stroke. Acute ischemic stroke, intracerebral hemorrhage, and cerebral venous sinus thrombosis have been reported in patients with COVID-19. COVID-19-associated coagulopathy is likely caused by inflammation. Resultant ACE2 down-regulation causes RAS imbalance, which may lead to stroke.
Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global health threat. Some COVID-19 patients have exhibited widespread neurological manifestations including stroke. Acute ischemic stroke, intracerebral hemorrhage, and cerebral venous sinus thrombosis have been reported in patients with COVID-19. COVID-19-associated coagulopathy is increasingly recognized as a result of acute infection and is likely caused by inflammation, including inflammatory cytokine storm. Recent studies suggest that axonal transport of SARS-CoV-2 to the brain can occur via the cribriform plate adjacent to the olfactory bulb that may lead to symptomatic anosmia. The internalization of SARS-CoV-2 is mediated by the binding of the spike glycoprotein of the virus to the angiotensin-converting enzyme 2 (ACE2) on cellular membranes. ACE2 is expressed in several tissues including lung alveolar cells, gastrointestinal tissue, and brain. The aim of this review is to provide insights into the clinical manifestations and pathophysiological mechanisms of stroke in COVID-19 patients. SARS-CoV-2 can down-regulate ACE2 and, in turn, overactivate the classical renin-angiotensin system (RAS) axis and decrease the activation of the alternative RAS pathway in the brain. The consequent imbalance in vasodilation, neuroinflammation, oxidative stress, and thrombotic response may contribute to the pathophysiology of stroke during SARS-CoV-2 infection.
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Affiliation(s)
- Afshin A Divani
- Department of Neurology, School of Medicine, University of New Mexico, Albuquerque 87131, New Mexico, USA.
| | - Sasan Andalib
- Department of Neurology, School of Medicine, University of New Mexico, Albuquerque 87131, New Mexico, USA; Research Unit of Clinical Physiology and Nuclear Medicine, Department of Nuclear Medicine, Odense University Hospital, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark; Neuroscience Research Center, Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
| | - Mario Di Napoli
- Department of Neurology and Stroke Unit, San Camillo de' Lellis District General Hospital, Rieti, Italy.
| | - Simona Lattanzi
- Neurological Clinic, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy.
| | - M Shazam Hussain
- Cerebrovascular Center, Department of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.
| | - José Biller
- Department of Neurology, Loyola University, Stritch School of Medicine, Maywood, IL, USA.
| | - Louise D McCullough
- Department of Neurology, McGovern Medical School, The University of Texas at Houston, Houston, TX, USA.
| | - M Reza Azarpazhooh
- Department of Clinical Neurological Sciences and Stroke Prevention & Atherosclerosis Research Center, Western University, London, Canada.
| | - Alina Seletska
- Department of Neurology, School of Medicine, University of New Mexico, Albuquerque 87131, New Mexico, USA.
| | - Stephan A Mayer
- Departments of Neurology and Neurosurgery, New York Medical College, Westchester Medical Center Health Network, Valhalla, NY, USA.
| | - Michel Torbey
- Department of Neurology, School of Medicine, University of New Mexico, Albuquerque 87131, New Mexico, USA.
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15
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Perdomo-Pantoja A, Chara A, Kalb S, Casaos J, Ahmed AK, Pennington Z, Cottrill E, Shah S, Jiang B, Manbachi A, Zygourakis C, Witham TF, Theodore N. The effect of renin-angiotensin system blockers on spinal cord dysfunction and imaging features of spinal cord compression in patients with symptomatic cervical spondylosis. Spine J 2020; 20:519-529. [PMID: 31821888 DOI: 10.1016/j.spinee.2019.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 10/31/2019] [Accepted: 12/02/2019] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Cervical spondylosis may lead to spinal cord compression, poor vascular perfusion, and ultimately, cervical myelopathy. Studies suggest a neuroprotective effect of renin-angiotensin system (RAS) inhibitors in the brain, but limited data exist regarding their impact on the spinal cord. PURPOSE To investigate whether RAS blockers and other antihypertensive drugs are correlated with preoperative functional status and imaging markers of cord compression in patients with symptomatic cervical spondylosis. STUDY DESIGN Retrospective observational study. PATIENT SAMPLE Individuals with symptomatic degenerative cervical stenosis who underwent surgery. OUTCOME MEASURES Imaging features of spinal cord compression and functional status (modified Japanese Orthopedic Association [mJOA] and Nurick grading scales). METHODS Two hundred sixty-six operative patients with symptomatic degenerative cervical stenosis were included. Demographic data, comorbidities, antihypertensive medications, and functional status (including mJOA and Nurick grading scales) were collected. We evaluated canal compromise, cord compromise, surface area of T2 signal cord change, and pixel intensity of signal cord change compared with normal cord on T2-weighted magnetic resonance imaging sequences. RESULTS Of 266 patients, 41.7% were women, 58.3% were men; median age was 57.2 years; 20.6% smoked tobacco; 24.7% had diabetes mellitus. One hundred forty-nine patients (55.8%) had hypertension, 142 (95.3%) of these were taking antihypertensive medications (37 angiotensin-II receptor blockers [ARBs], 44 angiotensin-converting enzyme inhibitors, and 61 other medications). Patients treated with ARBs displayed a higher signal intensity ratio (ie, less signal intensity change in the compressed cord area) compared with untreated patients without hypertension (p=.004). Patients with hypertension had worse preoperative mJOA and Nurick scores than those without (p<.001). In the multivariate analysis, ARBs remained an independent beneficial factor for lower signal intensity change (p=.04), whereas hypertension remained a risk factor for worse preoperative neurological status (p<.01). CONCLUSIONS In our study, patients with hypertension who were treated with RAS inhibitors had decreased T2-weighted signal intensity change than untreated patients without hypertension. Patients with hypertension also had worse preoperative functional status. Prospective case-control studies may deepen understanding of RAS modulators in the imaging and functional status of chronic spinal cord compression.
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Affiliation(s)
| | - Alejandro Chara
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - Samuel Kalb
- Division of Neurological Surgery, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Joshua Casaos
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - A Karim Ahmed
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - Zachary Pennington
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - Ethan Cottrill
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - Sohan Shah
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - Bowen Jiang
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - Amir Manbachi
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - Corinna Zygourakis
- Department of Neurosurgery, Stanford University School Of Medicine, Stanford, CA, USA
| | - Timothy F Witham
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA
| | - Nicholas Theodore
- Department of Neurosurgery, Johns Hopkins University School Of Medicine, Baltimore, MD, USA.
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16
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Patel S, Rahmani B, Gandhi J, Seyam O, Joshi G, Reid I, Smith NL, Waltzer WC, Khan SA. Revisiting the pineal gland: a review of calcification, masses, precocious puberty, and melatonin functions. Int J Neurosci 2020; 130:464-475. [PMID: 31714865 DOI: 10.1080/00207454.2019.1692838] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Introduction: The pineal gland, an endocrine organ of the posterior cranial fossa famously involved in sleep and wakefulness, has continually been a topic of scientific advancement and curiosity. Methods: We review present an up-to-date review including the anatomy, embryology, and physiology of the pineal gland and its ability to secrete hormones including melatonin, pathophysiology of pineal gland tumors, cysts, and calcifications, their clinical presentation including their association with parkinsonism and precocious puberty, and various treatment approaches. Results: Exploring the biochemistry of melatonin, various calcification morphologies, and pineal tumors may uncover a wider role and the exhaustive case study consolidation allows clinicians to carefully review the literature and aid their treatment approaches. Conclusion: It is imperative that clinicians and diagnosticians are able to distinguish manifestations of an overlooked gland.
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Affiliation(s)
- Shrey Patel
- Department of Physiology and Biophysics, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, USA
| | - Benjamin Rahmani
- Department of Physiology and Biophysics, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, USA
| | - Jason Gandhi
- Department of Physiology and Biophysics, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, USA.,Medical Student Research Institute, St. George's University School of Medicine, Grenada, West Indies
| | - Omar Seyam
- Department of Physiology and Biophysics, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, USA
| | - Gunjan Joshi
- Department of Internal Medicine, Stony Brook Southampton Hospital, Southampton, NY, USA
| | - Inefta Reid
- Department of Physiology and Biophysics, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, USA
| | | | - Wayne C Waltzer
- Department of Urology, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, USA
| | - Sardar Ali Khan
- Department of Physiology and Biophysics, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, USA.,Department of Urology, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, USA
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17
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Role of brain renin angiotensin system in neurodegeneration: An update. Saudi J Biol Sci 2020; 27:905-912. [PMID: 32127770 PMCID: PMC7042626 DOI: 10.1016/j.sjbs.2020.01.026] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 01/12/2023] Open
Abstract
Renin angiotensin system (RAS) is an endocrine system widely known for its physiological roles in electrolyte homeostasis, body fluid volume regulation and cardiovascular control in peripheral circulation. However, brain RAS is an independent form of RAS expressed locally in the brain, which is known to be involved in brain functions and disorders. There is strong evidence for a major involvement of excessive brain angiotensin converting enzyme (ACE)/Angiotensin II (Ang II)/Angiotensin type-1 receptor (AT-1R) axis in increased activation of oxidative stress, apoptosis and neuroinflammation causing neurodegeneration in several brain disorders. Numerous studies have demonstrated strong neuroprotective effects by blocking AT1R in these brain disorders. Additionally, the angiotensin converting enzyme 2 (ACE2)/Angiotensin (1–7)/Mas receptor (MASR), is another axis of brain RAS which counteracts the damaging effects of ACE/Ang II/AT1R axis on neurons in the brain. Thus, angiotensin II receptor blockers (ARBs) and activation of ACE2/Angiotensin (1–7)/MASR axis may serve as an exciting and novel method for neuroprotection in several neurodegenerative diseases. Here in this review article, we discuss the expression of RAS in the brain and highlight how altered RAS level may cause neurodegeneration. Understanding the pathophysiology of RAS and their links to neurodegeneration has enormous potential to identify potentially effective pharmacological tools to treat neurodegenerative diseases in the brain.
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18
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Heming N, Mazeraud A, Azabou E, Moine P, Annane D. Vasopressor Therapy and the Brain: Dark Side of the Moon. Front Med (Lausanne) 2020; 6:317. [PMID: 31998736 PMCID: PMC6966606 DOI: 10.3389/fmed.2019.00317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/13/2019] [Indexed: 12/14/2022] Open
Abstract
Sepsis, a leading cause of morbidity and mortality, is caused by a deregulated host response to pathogens, and subsequent life-threatening organ dysfunctions. All major systems, including the cardiovascular, respiratory, renal, hepatic, hematological, and the neurological system may be affected by sepsis. Sepsis associated neurological dysfunction is triggered by multiple factors including neuro-inflammation, excitotoxicity, and ischemia. Ischemia results from reduced cerebral blood flow, caused by extreme variations of blood pressure, occlusion of cerebral vessels, or more subtle defects of the microcirculation. International guidelines comprehensively describe the initial hemodynamic management of sepsis, revolving around the normalization of systemic hemodynamics and of arterial lactate. By contrast, the management of sepsis patients suffering from brain dysfunction is poorly detailed, the only salient point being mentioned is that sedation and analgesia should be optimized. However, sepsis and the hemodynamic consequences thereof as well as vasopressors may have severe untoward neurological consequences. The current review describes the general neurological complications, as well as the consequences of vasopressor therapy on the brain and its circulation and addresses methods for cerebral monitoring during sepsis.
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Affiliation(s)
- Nicholas Heming
- General Intensive Care Unit, Raymond Poincaré Hospital, Garches, France.,U1173 Lab Inflammation and Infection, University of Versailles SQY-Paris Saclay - INSERM, Montigny-le-Bretonneux, France
| | - Aurélien Mazeraud
- Department of Neuro-Anesthesiology and Intensive Care Medicine, Sainte-Anne Teaching Hospital, Paris-Descartes University, Paris, France
| | - Eric Azabou
- U1173 Lab Inflammation and Infection, University of Versailles SQY-Paris Saclay - INSERM, Montigny-le-Bretonneux, France.,Department of Physiology, Assistance Publique-Hôpitaux de Paris, Raymond-Poincaré Hospital, Garches, France
| | - Pierre Moine
- General Intensive Care Unit, Raymond Poincaré Hospital, Garches, France.,U1173 Lab Inflammation and Infection, University of Versailles SQY-Paris Saclay - INSERM, Montigny-le-Bretonneux, France
| | - Djillali Annane
- General Intensive Care Unit, Raymond Poincaré Hospital, Garches, France.,U1173 Lab Inflammation and Infection, University of Versailles SQY-Paris Saclay - INSERM, Montigny-le-Bretonneux, France
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19
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Díaz HS, Toledo C, Andrade DC, Marcus NJ, Del Rio R. Neuroinflammation in heart failure: new insights for an old disease. J Physiol 2020; 598:33-59. [PMID: 31671478 DOI: 10.1113/jp278864] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/09/2019] [Indexed: 08/25/2023] Open
Abstract
Heart failure (HF) is a complex clinical syndrome affecting roughly 26 million people worldwide. Increased sympathetic drive is a hallmark of HF and is associated with disease progression and higher mortality risk. Several mechanisms contribute to enhanced sympathetic activity in HF, but these pathways are still incompletely understood. Previous work suggests that inflammation and activation of the renin-angiotensin system (RAS) increases sympathetic drive. Importantly, chronic inflammation in several brain regions is commonly observed in aged populations, and a growing body of evidence suggests neuroinflammation plays a crucial role in HF. In animal models of HF, central inhibition of RAS and pro-inflammatory cytokines normalizes sympathetic drive and improves cardiac function. The precise molecular and cellular mechanisms that lead to neuroinflammation and its effect on HF progression remain undetermined. This review summarizes the most recent advances in the field of neuroinflammation and autonomic control in HF. In addition, it focuses on cellular and molecular mediators of neuroinflammation in HF and in particular on brain regions involved in sympathetic control. Finally, we will comment on what is known about neuroinflammation in the context of preserved vs. reduced ejection fraction HF.
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Affiliation(s)
- Hugo S Díaz
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Camilo Toledo
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - David C Andrade
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Noah J Marcus
- Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA, USA
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Envejecimiento y Regeneración (CARE-UC), Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
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20
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Meng X, McGraw CM, Wang W, Jing J, Yeh SY, Wang L, Lopez J, Brown AM, Lin T, Chen W, Xue M, Sillitoe RV, Jiang X, Zoghbi HY. Neurexophilin4 is a selectively expressed α-neurexin ligand that modulates specific cerebellar synapses and motor functions. eLife 2019; 8:e46773. [PMID: 31524598 PMCID: PMC6763262 DOI: 10.7554/elife.46773] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 09/13/2019] [Indexed: 01/03/2023] Open
Abstract
Neurexophilins are secreted neuropeptide-like glycoproteins, and neurexophilin1 and neurexophilin3 are ligands for the presynaptic cell adhesion molecule α-neurexin. Neurexophilins are more selectively expressed in the brain than α-neurexins, however, which led us to ask whether neurexophilins modulate the function of α-neurexin in a context-specific manner. We characterized the expression and function of neurexophilin4 in mice and found it to be expressed in subsets of neurons responsible for feeding, emotion, balance, and movement. Deletion of Neurexophilin4 caused corresponding impairments, most notably in motor learning and coordination. We demonstrated that neurexophilin4 interacts with α-neurexin and GABAARs in the cerebellum. Loss of Neurexophilin4 impaired cerebellar Golgi-granule inhibitory neurotransmission and synapse number, providing a partial explanation for the motor learning and coordination deficits observed in the Neurexophilin4 null mice. Our data illustrate how selectively expressed Neurexophilin4, an α-neurexin ligand, regulates specific synapse function and modulates cerebellar motor control.
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Affiliation(s)
- Xiangling Meng
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Christopher M McGraw
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Wei Wang
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Junzhan Jing
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Szu-Ying Yeh
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Li Wang
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Joanna Lopez
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Amanda M Brown
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Pathology and ImmunologyBaylor College of MedicineHoustonUnited States
| | - Tao Lin
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Pathology and ImmunologyBaylor College of MedicineHoustonUnited States
| | - Wu Chen
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- The Cain Foundation LaboratoriesJan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Mingshan Xue
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- The Cain Foundation LaboratoriesJan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Roy V Sillitoe
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Pathology and ImmunologyBaylor College of MedicineHoustonUnited States
| | - Xiaolong Jiang
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Huda Y Zoghbi
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
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21
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Wang Y, Sabbagh MF, Gu X, Rattner A, Williams J, Nathans J. Beta-catenin signaling regulates barrier-specific gene expression in circumventricular organ and ocular vasculatures. eLife 2019; 8:43257. [PMID: 30932813 PMCID: PMC6443350 DOI: 10.7554/elife.43257] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/17/2019] [Indexed: 12/29/2022] Open
Abstract
The brain, spinal cord, and retina are supplied by capillaries that do not permit free diffusion of molecules between serum and parenchyma, a property that defines the blood-brain and blood-retina barriers. Exceptions to this pattern are found in circumventricular organs (CVOs), small midline brain structures that are supplied by high permeability capillaries. In the eye and brain, high permeability capillaries are also present in the choriocapillaris, which supplies the retinal pigment epithelium and photoreceptors, and the ciliary body and choroid plexus, the sources of aqueous humor and cerebrospinal fluid, respectively. We show here that (1) endothelial cells in these high permeability vascular systems have very low beta-catenin signaling compared to barrier-competent endothelial cells, and (2) elevating beta-catenin signaling leads to a partial conversion of permeable endothelial cells to a barrier-type state. In one CVO, the area postrema, high permeability is maintained, in part, by local production of Wnt inhibitory factor-1.
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Affiliation(s)
- Yanshu Wang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Mark F Sabbagh
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Xiaowu Gu
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Amir Rattner
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States
| | - John Williams
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, United States
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22
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McKinley MJ, Denton DA, Ryan PJ, Yao ST, Stefanidis A, Oldfield BJ. From sensory circumventricular organs to cerebral cortex: Neural pathways controlling thirst and hunger. J Neuroendocrinol 2019; 31:e12689. [PMID: 30672620 DOI: 10.1111/jne.12689] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/20/2019] [Accepted: 01/21/2019] [Indexed: 01/14/2023]
Abstract
Much progress has been made during the past 30 years with respect to elucidating the neural and endocrine pathways by which bodily needs for water and energy are brought to conscious awareness through the generation of thirst and hunger. One way that circulating hormones influence thirst and hunger is by acting on neurones within sensory circumventricular organs (CVOs). This is possible because the subfornical organ and organum vasculosum of the lamina terminalis (OVLT), the sensory CVOs in the forebrain, and the area postrema in the hindbrain lack a normal blood-brain barrier such that neurones within them are exposed to blood-borne agents. The neural signals generated by hormonal action in these sensory CVOs are relayed to several sites in the cerebral cortex to stimulate or inhibit thirst or hunger. The subfornical organ and OVLT respond to circulating angiotensin II, relaxin and hypertonicity to drive thirst-related neural pathways, whereas circulating amylin, leptin and possibly glucagon-like peptide-1 act at the area postrema to influence neural pathways inhibiting food intake. As a result of investigations using functional brain imaging techniques, the insula and anterior cingulate cortex, as well as several other cortical sites, have been implicated in the conscious perception of thirst and hunger in humans. Viral tracing techniques show that the anterior cingulate cortex and insula receive neural inputs from thirst-related neurones in the subfornical organ and OVLT, with hunger-related neurones in the area postrema having polysynaptic efferent connections to these cortical regions. For thirst, initially, the median preoptic nucleus and, subsequently, the thalamic paraventricular nucleus and lateral hypothalamus have been identified as likely sites of synaptic links in pathways from the subfornical organ and OVLT to the cortex. The challenge remains to identify the links in the neural pathways that relay signals originating in sensory CVOs to cortical sites subserving either thirst or hunger.
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Affiliation(s)
- Michael J McKinley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Derek A Denton
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Office of the Dean of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Philip J Ryan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Song T Yao
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Aneta Stefanidis
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Brian J Oldfield
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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23
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Abstract
PURPOSE OF REVIEW This review summarizes the organization and structure of vagal neurocircuits controlling the upper gastrointestinal tract, and more recent studies investigating their role in the regulation of gastric motility under physiological, as well as pathophysiological, conditions. RECENT FINDINGS Vagal neurocircuits regulating gastric functions are highly plastic, and open to modulation by a variety of inputs, both peripheral and central. Recent research in the fields of obesity, development, stress, and neurological disorders highlight the importance of central inputs onto these brainstem neurocircuits in the regulation of gastric motility. SUMMARY Recognition of the pivotal role that the central nervous system exerts in the regulation, integration, and modulation of gastric motility should serve to encourage research into central mechanisms regulating peripheral motility disorders.
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Affiliation(s)
- Kirsteen N Browning
- Department of Neural and Behavioral Science, Penn State College of Medicine, Hershey, Pennsylvania, USA
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24
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Rossi NF, Zenner Z, Rishi AK, Levi E, Maliszewska-Scislo M. AT 1 receptors in the subfornical organ modulate arterial pressure and the baroreflex in two-kidney, one-clip hypertensive rats. Am J Physiol Regul Integr Comp Physiol 2019; 316:R172-R185. [PMID: 30624974 DOI: 10.1152/ajpregu.00289.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The subfornical organ (SFO), a forebrain circumventricular organ that lies outside the blood-brain barrier, has been implicated in arterial pressure and baroreflex responses to angiotensin II (ANG II). We tested whether pharmacological inhibition or selective silencing of SFO ANG II type 1 receptors (AT1R) of two-kidney, one-clip rats with elevated plasma ANG II decreases resting arterial pressure and renal sympathetic nerve activity (RSNA) and/or modulates arterial baroreflex responses of heart rate (HR) and RSNA. Male Sprague-Dawley rats underwent renal artery clipping [2-kidney, 1-clip (2K,1C)] or sham clipping (sham). After 6 wk, conscious rats instrumented with vascular catheters, renal nerve electrodes, and a cannula directed to the SFO were studied. In another set of experiments, rats were instrumented with hemodynamic and nerve radio transmitters and injected with scrambled RNA or silencing RNA targeted against AT1R. Mean arterial pressure (MAP) was significantly higher in 2K,1C rats. Acute SFO injection with the AT1R inhibitor losartan did not change MAP in sham or 2K,1C rats. Baroreflex curves of HR and RSNA were shifted rightward in 2K,1C rats. Losartan exerted no effect. SFO AT1R knockdown did not influence MAP in sham rats but decreased MAP in 2K,1C rats, despite no change in plasma ANG II or resting RSNA. AT1R knockdown prevented the reduction in maximum gain and slope of baroreflex responses of HR and RSNA; the reduced RSNA response to baroreceptor unloading was partially restored in 2K,1C rats. These findings show that AT1R activation within the SFO contributes to hypertension and baroreflex dysfunction in 2K,1C rats and highlight the temporal requirement for reversal of these effects.
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Affiliation(s)
- Noreen F Rossi
- Departments of Internal Medicine and Physiology, Wayne State University School of Medicine , Detroit, Michigan.,John D. Dingell Veterans Administration Medical Center , Detroit, Michigan
| | - Zachary Zenner
- Departments of Internal Medicine and Physiology, Wayne State University School of Medicine , Detroit, Michigan
| | - Arun K Rishi
- Department of Oncology, Wayne State University School of Medicine , Detroit, Michigan.,John D. Dingell Veterans Administration Medical Center , Detroit, Michigan
| | - Edi Levi
- Department of Pathology, Wayne State University School of Medicine , Detroit, Michigan.,John D. Dingell Veterans Administration Medical Center , Detroit, Michigan
| | - Maria Maliszewska-Scislo
- Departments of Internal Medicine and Physiology, Wayne State University School of Medicine , Detroit, Michigan
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25
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Schier LA, Spector AC. The Functional and Neurobiological Properties of Bad Taste. Physiol Rev 2019; 99:605-663. [PMID: 30475657 PMCID: PMC6442928 DOI: 10.1152/physrev.00044.2017] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 05/18/2018] [Accepted: 06/30/2018] [Indexed: 12/12/2022] Open
Abstract
The gustatory system serves as a critical line of defense against ingesting harmful substances. Technological advances have fostered the characterization of peripheral receptors and have created opportunities for more selective manipulations of the nervous system, yet the neurobiological mechanisms underlying taste-based avoidance and aversion remain poorly understood. One conceptual obstacle stems from a lack of recognition that taste signals subserve several behavioral and physiological functions which likely engage partially segregated neural circuits. Moreover, although the gustatory system evolved to respond expediently to broad classes of biologically relevant chemicals, innate repertoires are often not in register with the actual consequences of a food. The mammalian brain exhibits tremendous flexibility; responses to taste can be modified in a specific manner according to bodily needs and the learned consequences of ingestion. Therefore, experimental strategies that distinguish between the functional properties of various taste-guided behaviors and link them to specific neural circuits need to be applied. Given the close relationship between the gustatory and visceroceptive systems, a full reckoning of the neural architecture of bad taste requires an understanding of how these respective sensory signals are integrated in the brain.
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Affiliation(s)
- Lindsey A Schier
- Department of Biological Sciences, University of Southern California , Los Angeles, California ; and Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Alan C Spector
- Department of Biological Sciences, University of Southern California , Los Angeles, California ; and Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
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26
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Caron A, Briscoe DM, Richard D, Laplante M. DEPTOR at the Nexus of Cancer, Metabolism, and Immunity. Physiol Rev 2018; 98:1765-1803. [PMID: 29897294 DOI: 10.1152/physrev.00064.2017] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
DEP domain-containing mechanistic target of rapamycin (mTOR)-interacting protein (DEPTOR) is an important modulator of mTOR, a kinase at the center of two important protein complexes named mTORC1 and mTORC2. These highly studied complexes play essential roles in regulating growth, metabolism, and immunity in response to mitogens, nutrients, and cytokines. Defects in mTOR signaling have been associated with the development of many diseases, including cancer and diabetes, and approaches aiming at modulating mTOR activity are envisioned as an attractive strategy to improve human health. DEPTOR interaction with mTOR represses its kinase activity and rewires the mTOR signaling pathway. Over the last years, several studies have revealed key roles for DEPTOR in numerous biological and pathological processes. Here, we provide the current state of the knowledge regarding the cellular and physiological functions of DEPTOR by focusing on its impact on the mTOR pathway and its role in promoting health and disease.
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Affiliation(s)
- Alexandre Caron
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center , Dallas, Texas ; Transplant Research Program, Boston Children's Hospital , Boston, Massachusetts ; Department of Pediatrics, Harvard Medical School , Boston, Massachusetts ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval , Québec , Canada ; and Centre de Recherche sur le Cancer de l'Université Laval, Université Laval , Québec , Canada
| | - David M Briscoe
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center , Dallas, Texas ; Transplant Research Program, Boston Children's Hospital , Boston, Massachusetts ; Department of Pediatrics, Harvard Medical School , Boston, Massachusetts ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval , Québec , Canada ; and Centre de Recherche sur le Cancer de l'Université Laval, Université Laval , Québec , Canada
| | - Denis Richard
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center , Dallas, Texas ; Transplant Research Program, Boston Children's Hospital , Boston, Massachusetts ; Department of Pediatrics, Harvard Medical School , Boston, Massachusetts ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval , Québec , Canada ; and Centre de Recherche sur le Cancer de l'Université Laval, Université Laval , Québec , Canada
| | - Mathieu Laplante
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center , Dallas, Texas ; Transplant Research Program, Boston Children's Hospital , Boston, Massachusetts ; Department of Pediatrics, Harvard Medical School , Boston, Massachusetts ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval , Québec , Canada ; and Centre de Recherche sur le Cancer de l'Université Laval, Université Laval , Québec , Canada
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27
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Alpár A, Benevento M, Romanov RA, Hökfelt T, Harkany T. Hypothalamic cell diversity: non-neuronal codes for long-distance volume transmission by neuropeptides. Curr Opin Neurobiol 2018; 56:16-23. [PMID: 30471413 DOI: 10.1016/j.conb.2018.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/24/2018] [Indexed: 11/24/2022]
Abstract
Volume transmission is a mode of intercellular communication using cerebral liquor to deliver signal molecules over long distances and allow their action for extended periods. For hypothalamic neuropeptides, nerve endings amongst ependymal cells are seen as a site of release into the cerebrospinal fluid. Recent single-cell RNA-seq data identify tanycytes and ventricular ependyma as alternative sources by being unexpectedly rich in neuroactive substances. This notion, coupled with circuit analysis showing regionalized innervation of periventricular ependyma by intrahypothalamic neurons, could allow for the integration of hypothalamic neuronal activity patterns with brain-wide activity changes upon metabolic challenges through phasic volume transmission primed by neuron-ependyma coupling. Here, we discuss emerging data for an ependymal interface and its breaches in neuropsychiatric disease.
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Affiliation(s)
- Alán Alpár
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, H-1085 Budapest, Hungary; Department of Anatomy, Histology, and Embryology, Semmelweis University, H-1085 Budapest, Hungary
| | - Marco Benevento
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria
| | - Roman A Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, SE-17165 Solna, Sweden
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria; Department of Neuroscience, Karolinska Institutet, SE-17165 Solna, Sweden.
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28
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Al-Kaabi M, Hussam F, Al-Marsoummi S, Al-Anbaki A, Al-Salihi A, Al-Aubaidy H. Expression of ZO1, vimentin, pan-cadherin and AGTR1 in tanycyte-like cells of the sulcus medianus organum. Biochem Biophys Res Commun 2018; 502:243-249. [PMID: 29803674 DOI: 10.1016/j.bbrc.2018.05.151] [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: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 11/19/2022]
Abstract
Tanycytes are a specialized ependymal lining of brain ventricles with exceptional features of having long basal processes and junctional complexes between cell bodies. These tanycytes are present at the regions of circumventricular organs (CVOs) which possess common morphological and functional features enabling them to be described as the brain windows where the barrier systems have special properties. Previous studies detailed seven of these CVOs but little information is available regarding another putative site at the rostral part of the median sulcus of the 4th ventricle, or the sulcus medianus organum (SMO). Here we performed a pilot immunohistochemical study to support earlier observations suggesting the SMO as a novel CVO. We labeled rat brain with ZO1, vimentin, pan-cadherin and angiotensin II type 1 receptors markers which showed a morphologically distinct population of cells at the region of the SMO similar to tanycytes present in the median eminence, a known CVO. These cells had basal processes reaching the deeply seated blood vessels while the caudal part of the median sulcus did not show similar long cellular extensions. We concluded that tanycyte-like cells are present in the SMO in a pattern resembling that of other CVOs where the strategic location of the SMO is probably for signal integration between brainstem nuclei and the rostrally located neuronal centers.
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Affiliation(s)
- Muthanna Al-Kaabi
- Al-Nahrain University, College of Medicine, Department of Human Anatomy, Baghdad, Iraq; University of Tasmania, Faculty of Health, School of Medicine, Medical Science Precinct, Hobart, Tasmania, Australia
| | - Fadhil Hussam
- Al-Nahrain University, College of Medicine, Department of Human Anatomy, Baghdad, Iraq
| | - Sarmad Al-Marsoummi
- Al-Nahrain University, College of Medicine, Department of Human Anatomy, Baghdad, Iraq; University of North Dakota, School of Medicine and Health Sciences, Department of Biomedical Sciences, North Dakota, USA
| | - Ali Al-Anbaki
- University of Manchester, Faculty of Biology, Medicine and Health, Manchester, UK
| | - Anam Al-Salihi
- Al-Nahrain University, College of Medicine, Department of Human Anatomy, Baghdad, Iraq
| | - Hayder Al-Aubaidy
- La Trobe University, School of Life Sciences, Department of Physiology, Anatomy & Microbiology, Bundoora, VIC, 3086, Australia.
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29
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Peterson CS, Huang S, Lee SA, Ferguson AV, Fry WM. The transcriptome of the rat subfornical organ is altered in response to early postnatal overnutrition. IBRO Rep 2018; 5:17-23. [PMID: 30135952 PMCID: PMC6095096 DOI: 10.1016/j.ibror.2018.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 06/12/2018] [Indexed: 01/18/2023] Open
Abstract
Early postnatal overnutrition in humans is associated with long-term negative outcomes including obesity, increased risk of type-II diabetes, and cardiovascular disease. Hypothalamic neurons from rodents exposed to early postnatal overnutrition show altered expression of satiety signals and receptors, and exhibit altered responses to many satiety signals, suggesting a hypothalamic link between early overnutrition and development of these sequelae. Importantly, several hypothalamic nuclei receive information regarding circulating hormones (such as insulin, leptin and ghrelin) from the subfornical organ (SFO), a forebrain sensory circumventricular organ which lacks a blood brain barrier. Previous transcriptomic studies indicate that challenges to energy balance and hydration status stimulate changes in gene expression within the SFO, including genes encoding ion channels and receptors. In order to determine if early postnatal overnutrition also causes changes in SFO gene expression which may be associated with homeostatic dysregulation, we performed whole transcriptome sequencing on SFO tissue from rats raised in small (4 pups), or control (large, 12 pups) litters. Illumina RNA sequencing was performed on SFO tissue from rats raised from small and large litters, and read sequences were aligned to the Rat Rnor_6.0 genome. Control data were further compared to previously published microarray data set for validation. We found statistically significant (p < 0.05) changes in expression of 12 transcripts, three of which have likely roles in neuronal excitability, neurite outgrowth and differentiation, and food intake (Manf, Slc24a4, Cracr2b). Additionally, gene ontology analysis identified a trend among significantly altered transcripts in roles for oxidative stress response. We conclude that the SFO transcriptome is subtly altered by early postnatal overnutrition, and recommend further investigation of the effect of early postnatal overnutrition on SFO physiology and morphology.
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Affiliation(s)
- Colleen S Peterson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Shuo Huang
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Samantha A Lee
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - A V Ferguson
- Centre for Neuroscience, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - W Mark Fry
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
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30
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Renin angiotensin system and its role in biomarkers and treatment in gliomas. J Neurooncol 2018; 138:1-15. [PMID: 29450812 DOI: 10.1007/s11060-018-2789-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 02/01/2018] [Indexed: 12/14/2022]
Abstract
Gliomas are the most common primary intrinsic tumor in the brain and are classified as low- or high-grade according to the World Health Organization (WHO). Patients with high-grade gliomas (HGG) who undergo surgical resection with adjuvant therapy have a mean overall survival of 15 months and 100% recurrence. The renin-angiotensin system (RAS), the primary regulator of cardiovascular circulation, exhibits local action and works as a paracrine system. In the context of this local regulation, the expression of RAS peptides and receptors has been detected in different kinds of tumors, including gliomas. The dysregulation of RAS components plays a significant role in the proliferation, angiogenesis, and invasion of these tumors, and therefore in their outcomes. The study and potential application of RAS peptides and receptors as biomarkers in gliomas could bring advantages against the limitations of current tumoral markers and should be considered in the future. The targeting of RAS components by RAS blockers has shown potential of being protective against cancer and improving immunotherapy. In gliomas, RAS blockers have shown a broad spectrum for beneficial effects and are being considered for use in treatment protocols. This review aims to summarize the background behind how RAS plays a role in gliomagenesis and explore the evidence that could lead to their use as biomarkers and treatment adjuvants.
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31
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Gabriel Knoll J, Krasnow SM, Marks DL. Interleukin-1β signaling in fenestrated capillaries is sufficient to trigger sickness responses in mice. J Neuroinflammation 2017; 14:219. [PMID: 29121947 PMCID: PMC5680784 DOI: 10.1186/s12974-017-0990-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/30/2017] [Indexed: 11/13/2023] Open
Abstract
BACKGROUND The physiological and behavioral symptoms of sickness, including fever, anorexia, behavioral depression, and weight loss can be both beneficial and detrimental. These sickness responses are triggered by pro-inflammatory cytokines acting on cells within the brain. Previous research demonstrates that the febrile response to peripheral insults depends upon prostaglandin production by vascular endothelial cells, but the mechanisms and specific cell type(s) responsible for other sickness responses remain unknown. The purpose of the present study was to identify which cells within the brain are required for sickness responses triggered by central nervous system inflammation. METHODS Intracerebroventricular (ICV) administration of 10 ng of the potent pro-inflammatory cytokine interleukin-1β (IL-1β) was used as an experimental model of central nervous system cytokine production. We examined which cells respond to IL-1β in vivo via fluorescent immunohistochemistry. Using multiple transgenic mouse lines expressing Cre recombinase under the control of cell-specific promoters, we eliminated IL-1β signaling from different populations of cells. Food consumption, body weight, movement, and temperature were recorded in adult male mice and analyzed by two-factor ANOVA to determine where IL-1β signaling is essential for sickness responses. RESULTS Endothelial cells, microglia, ependymal cells, and astrocytes exhibit nuclear translocation of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) in response to IL-1β. Interfering with IL-1β signaling in microglia, endothelial cells within the parenchyma of the brain, or both did not affect sickness responses. Only mice that lacked IL-1β signaling in all endothelium including fenestrated capillaries lacked sickness responses. CONCLUSIONS These experiments show that IL-1β-induced sickness responses depend on intact IL-1β signaling in blood vessels and suggest that fenestrated capillaries act as a critical signaling relay between the immune and nervous systems. TRIAL REGISTRATION Not applicable.
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Affiliation(s)
- J. Gabriel Knoll
- Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, Mail Code L481 3181 SW Sam Jackson Park Rd, Portland, OR 97239 USA
| | - Stephanie M. Krasnow
- Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, Mail Code L481 3181 SW Sam Jackson Park Rd, Portland, OR 97239 USA
| | - Daniel L. Marks
- Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, Mail Code L481 3181 SW Sam Jackson Park Rd, Portland, OR 97239 USA
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32
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Holmstrup P, Damgaard C, Olsen I, Klinge B, Flyvbjerg A, Nielsen CH, Hansen PR. Comorbidity of periodontal disease: two sides of the same coin? An introduction for the clinician. J Oral Microbiol 2017; 9:1332710. [PMID: 28748036 PMCID: PMC5508374 DOI: 10.1080/20002297.2017.1332710] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/07/2017] [Indexed: 12/14/2022] Open
Abstract
Increasing evidence has suggested an independent association between periodontitis and a range of comorbidities, for example cardiovascular disease, type 2 diabetes, rheumatoid arthritis, osteoporosis, Parkinson’s disease, Alzheimer’s disease, psoriasis, and respiratory infections. Shared inflammatory pathways are likely to contribute to this association, but distinct causal mechanisms remain to be defined. Some of these comorbid conditions may improve by periodontal treatment, and a bidirectional relationship may exist, where, for example, treatment of diabetes can improve periodontal status. The present article presents an overview of the evidence linking periodontitis with selected systemic diseases and calls for increased cooperation between dentists and medical doctors to provide optimal screening, treatment, and prevention of both periodontitis and its comorbidities.
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Affiliation(s)
- Palle Holmstrup
- Section for Periodontology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian Damgaard
- Section for Periodontology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Björn Klinge
- Department of Periodontology, Faculty of Odontology, Malmö University, Malmö, Sweden.,Division of Periodontology, Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Claus Henrik Nielsen
- Section for Periodontology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Peter Riis Hansen
- Section for Periodontology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Cardiology Department, Herlev and Gentofte Hospital, Hellerup, Denmark
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33
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McMenamin CA, Travagli RA, Browning KN. Inhibitory neurotransmission regulates vagal efferent activity and gastric motility. Exp Biol Med (Maywood) 2017; 241:1343-50. [PMID: 27302177 DOI: 10.1177/1535370216654228] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The gastrointestinal tract receives extrinsic innervation from both the sympathetic and parasympathetic nervous systems, which regulate and modulate the function of the intrinsic (enteric) nervous system. The stomach and upper gastrointestinal tract in particular are heavily influenced by the parasympathetic nervous system, supplied by the vagus nerve, and disruption of vagal sensory or motor functions results in disorganized motility patterns, disrupted receptive relaxation and accommodation, and delayed gastric emptying, amongst others. Studies from several laboratories have shown that the activity of vagal efferent motoneurons innervating the upper GI tract is inhibited tonically by GABAergic synaptic inputs from the adjacent nucleus tractus solitarius. Disruption of this influential central GABA input impacts vagal efferent output, hence gastric functions, significantly. The purpose of this review is to describe the development, physiology, and pathophysiology of this functionally dominant inhibitory synapse and its role in regulating vagally determined gastric functions.
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Affiliation(s)
- Caitlin A McMenamin
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, USA
| | - R Alberto Travagli
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Kirsteen N Browning
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, USA
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Agassandian K, Grobe JL, Liu X, Agassandian M, Thompson AP, Sigmund CD, Cassell MD. Evidence for intraventricular secretion of angiotensinogen and angiotensin by the subfornical organ using transgenic mice. Am J Physiol Regul Integr Comp Physiol 2017; 312:R973-R981. [PMID: 28490451 PMCID: PMC5495920 DOI: 10.1152/ajpregu.00511.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 05/03/2017] [Accepted: 05/03/2017] [Indexed: 01/05/2023]
Abstract
Direct intracerebroventricular injection of angiotensin II (ANG II) causes increases in blood pressure and salt and water intake, presumably mimicking an effect mediated by an endogenous mechanism. The subfornical organ (SFO) is a potential source of cerebrospinal fluid (CSF), ANG I, and ANG II, and thus we hypothesized that the SFO has a secretory function. Endogenous levels of angiotensinogen (AGT) and renin are very low in the brain. We therefore examined the immunohistochemical localization of angiotensin peptides and AGT in the SFO, and AGT in the CSF in two transgenic models that overexpress either human AGT (A+ mice), or both human AGT (hAGT) and human renin (SRA mice) in the brain. Measurements were made at baseline and following volumetric depletion of CSF. Ultrastructural analysis with immunoelectron microscopy revealed that superficially located ANG I/ANG II and AGT immunoreactive cells in the SFO were vacuolated and opened directly into the ventricle. Withdrawal of CSF produced an increase in AGT in the CSF that was accompanied by a large decline in AGT immunoreactivity within SFO cells. Our data provide support for the hypothesis that the SFO is a secretory organ that releases AGT and possibly ANG I/ANG II into the ventricle at least under conditions when genes that control the renin-angiotensin system are overexpressed in mice.
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Affiliation(s)
- Khristofor Agassandian
- Department of Anatomy and Cell Biology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Justin L Grobe
- UIHC Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Xuebo Liu
- UIHC Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Marianna Agassandian
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Anthony P Thompson
- Department of Anatomy and Cell Biology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa.,UIHC Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Curt D Sigmund
- UIHC Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; .,Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Martin D Cassell
- Department of Anatomy and Cell Biology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa.,UIHC Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
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Clarifying the Ghrelin System's Ability to Regulate Feeding Behaviours Despite Enigmatic Spatial Separation of the GHSR and Its Endogenous Ligand. Int J Mol Sci 2017; 18:ijms18040859. [PMID: 28422060 PMCID: PMC5412441 DOI: 10.3390/ijms18040859] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/04/2017] [Accepted: 04/11/2017] [Indexed: 12/23/2022] Open
Abstract
Ghrelin is a hormone predominantly produced in and secreted from the stomach. Ghrelin is involved in many physiological processes including feeding, the stress response, and in modulating learning, memory and motivational processes. Ghrelin does this by binding to its receptor, the growth hormone secretagogue receptor (GHSR), a receptor found in relatively high concentrations in hypothalamic and mesolimbic brain regions. While the feeding and metabolic effects of ghrelin can be explained by the effects of this hormone on regions of the brain that have a more permeable blood brain barrier (BBB), ghrelin produced within the periphery demonstrates a limited ability to reach extrahypothalamic regions where GHSRs are expressed. Therefore, one of the most pressing unanswered questions plaguing ghrelin research is how GHSRs, distributed in brain regions protected by the BBB, are activated despite ghrelin’s predominant peripheral production and poor ability to transverse the BBB. This manuscript will describe how peripheral ghrelin activates central GHSRs to encourage feeding, and how central ghrelin synthesis and ghrelin independent activation of GHSRs may also contribute to the modulation of feeding behaviours.
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Mazeraud A, Pascal Q, Verdonk F, Heming N, Chrétien F, Sharshar T. Neuroanatomy and Physiology of Brain Dysfunction in Sepsis. Clin Chest Med 2017; 37:333-45. [PMID: 27229649 DOI: 10.1016/j.ccm.2016.01.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sepsis-associated encephalopathy (SAE), a complication of sepsis, is often complicated by acute and long-term brain dysfunction. SAE is associated with electroencephalogram pattern changes and abnormal neuroimaging findings. The major processes involved are neuroinflammation, circulatory dysfunction, and excitotoxicity. Neuroinflammation and microcirculatory alterations are diffuse, whereas excitotoxicity might occur in more specific structures involved in the response to stress and the control of vital functions. A dysfunction of the brainstem, amygdala, and hippocampus might account for the increased mortality, psychological disorders, and cognitive impairment. This review summarizes clinical and paraclinical features of SAE and describes its mechanisms at cellular and structural levels.
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Affiliation(s)
- Aurelien Mazeraud
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France; Sorbonne Paris Cité, Paris Descartes University, Rue de l'école de médecine, Paris 75006, France; General Intensive Care, Assistance Publique Hopitaux de Paris, Raymond Poincaré Teaching Hosptal, Garches 92380, France
| | - Quentin Pascal
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France
| | - Franck Verdonk
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France; Sorbonne Paris Cité, Paris Descartes University, Rue de l'école de médecine, Paris 75006, France
| | - Nicholas Heming
- General Intensive Care, Assistance Publique Hopitaux de Paris, Raymond Poincaré Teaching Hosptal, Garches 92380, France
| | - Fabrice Chrétien
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France; Sorbonne Paris Cité, Paris Descartes University, Rue de l'école de médecine, Paris 75006, France; Laboratoire de Neuropathologie, Centre Hospitalier Sainte Anne, 1 rue cabanis, Paris 75014, France
| | - Tarek Sharshar
- Institut Pasteur - Unité Histopathologie Humaine et Modèles Animaux, Département Infection et Épidémiologie, Rue du docteur roux, Paris 75724 Cedex 15, France; General Intensive Care, Assistance Publique Hopitaux de Paris, Raymond Poincaré Teaching Hosptal, Garches 92380, France; Versailles-Saint Quentin University, Avenue de Paris, Versailles 78000, France.
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Sterkel S, Akinyemi A, Sanchez-Gonzalez MA, Michel G. Preserving brain function in a comatose patient with septic hyperpyrexia (41.6 °C): a case report. J Med Case Rep 2017; 11:40. [PMID: 28190402 PMCID: PMC5304390 DOI: 10.1186/s13256-017-1204-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 01/06/2017] [Indexed: 11/12/2022] Open
Abstract
Background Pyrexia is a physiological response through which the immune system responds to infectious processes. Hyperpyrexia is known to be neurodegenerative leading to brain damage. Some of the neurotoxic effects of hyperpyrexia on the brain include seizures, decreased cognitive speed, mental status changes, coma, and even death. In the clinical management of hyperpyrexia, the goal is to treat the underlying cause of elevated temperature and prevent end organ damage. Case presentation This case illustrates a 39-year-old white American man referred from another medical facility where he had undergone an upper gastrointestinal tract diagnostic procedure which became complicated by blood aspiration and respiratory distress. During hospitalization, he developed a core body temperature of 41.6 °C (106.9 °F) leading to cognitive decline and coma with a Glasgow Coma Score of 3. Levetiracetam and amantadine were utilized effectively for preserving and restoring neurocognitive function. Prior studies have shown that glutamate levels can increase during an infectious process. Glutamate is an excitatory neurotransmitter that is utilized by the organum vasculosum laminae terminalis through the neuronal excitatory system and causes an increase in body temperature which can lead to hyperpyrexia. Similar to neurogenic fevers, hyperpyrexia can lead to neurological decline and irreversible cognitive dysfunction. Inhibition of the glutamate aids a decrease in excitatory states, and improves the brain’s regulatory mechanism, including temperature control. To further improve cognitive function, dopamine levels were increased with a dopamine agonist. Conclusions We propose that a combination of levetiracetam and amantadine may provide neuroprotective and neurorestorative properties when administered during a period of hyperpyrexia accompanied by any form of mental status changes, particularly if there is a decline in Glasgow Coma Score.
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Affiliation(s)
- Samantha Sterkel
- Department of Internal Medicine, Larkin Community Hospital, Graduate Medical Education, 7000 SW 62nd Avenue, Suite 401, South Miami, FL, 33142, USA
| | - Akinboyede Akinyemi
- Department of Psychiatry, Larkin Community Hospital, Graduate Medical Education, 7000 SW 62nd Avenue, Suite 401, South Miami, FL, 33142, USA.
| | | | - George Michel
- Department of Internal Medicine, Larkin Community Hospital, Graduate Medical Education, 7000 SW 62nd Avenue, Suite 401, South Miami, FL, 33142, USA
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Sterkel S, Akinyemi A, Sanchez-Gonzalez MA, Michel G. Preserving brain function in a comatose patient with septic hyperpyrexia (41.6 °C): a case report. J Med Case Rep 2017. [PMID: 28190402 DOI: 10.1186/s13256--017--1204--8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2022] Open
Abstract
BACKGROUND Pyrexia is a physiological response through which the immune system responds to infectious processes. Hyperpyrexia is known to be neurodegenerative leading to brain damage. Some of the neurotoxic effects of hyperpyrexia on the brain include seizures, decreased cognitive speed, mental status changes, coma, and even death. In the clinical management of hyperpyrexia, the goal is to treat the underlying cause of elevated temperature and prevent end organ damage. CASE PRESENTATION This case illustrates a 39-year-old white American man referred from another medical facility where he had undergone an upper gastrointestinal tract diagnostic procedure which became complicated by blood aspiration and respiratory distress. During hospitalization, he developed a core body temperature of 41.6 °C (106.9 °F) leading to cognitive decline and coma with a Glasgow Coma Score of 3. Levetiracetam and amantadine were utilized effectively for preserving and restoring neurocognitive function. Prior studies have shown that glutamate levels can increase during an infectious process. Glutamate is an excitatory neurotransmitter that is utilized by the organum vasculosum laminae terminalis through the neuronal excitatory system and causes an increase in body temperature which can lead to hyperpyrexia. Similar to neurogenic fevers, hyperpyrexia can lead to neurological decline and irreversible cognitive dysfunction. Inhibition of the glutamate aids a decrease in excitatory states, and improves the brain's regulatory mechanism, including temperature control. To further improve cognitive function, dopamine levels were increased with a dopamine agonist. CONCLUSIONS We propose that a combination of levetiracetam and amantadine may provide neuroprotective and neurorestorative properties when administered during a period of hyperpyrexia accompanied by any form of mental status changes, particularly if there is a decline in Glasgow Coma Score.
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Affiliation(s)
- Samantha Sterkel
- Department of Internal Medicine, Larkin Community Hospital, Graduate Medical Education, 7000 SW 62nd Avenue, Suite 401, South Miami, FL, 33142, USA
| | - Akinboyede Akinyemi
- Department of Psychiatry, Larkin Community Hospital, Graduate Medical Education, 7000 SW 62nd Avenue, Suite 401, South Miami, FL, 33142, USA.
| | | | - George Michel
- Department of Internal Medicine, Larkin Community Hospital, Graduate Medical Education, 7000 SW 62nd Avenue, Suite 401, South Miami, FL, 33142, USA
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Rubin K, Glazer S. The pertussis hypothesis: Bordetella pertussis colonization in the pathogenesis of Alzheimer’s disease. Immunobiology 2017; 222:228-240. [DOI: 10.1016/j.imbio.2016.09.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 09/26/2016] [Indexed: 12/31/2022]
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Cerajewska TL, Davies M, West NX. Periodontitis: a potential risk factor for Alzheimer's disease. Br Dent J 2016; 218:29-34. [PMID: 25571822 DOI: 10.1038/sj.bdj.2014.1137] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2014] [Indexed: 01/12/2023]
Abstract
The role of periodontitis as a risk factor for multiple systemic diseases is widely accepted and there is growing evidence of an association between periodontitis and sporadic late onset Alzheimer's disease (SLOAD). Recent epidemiologic, microbiologic and inflammatory findings strengthen this association, indicating that periodontal pathogens are possible contributors to neural inflammation and SLOAD. The aim of this article is to present contemporary evidence of this association.
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Affiliation(s)
- T L Cerajewska
- Clinical Trials Group, School of Oral and Dental Science, Lower Maudlin Street, University of Bristol, Bristol, BS1 2LY
| | - M Davies
- Clinical Trials Group, School of Oral and Dental Science, Lower Maudlin Street, University of Bristol, Bristol, BS1 2LY
| | - N X West
- Clinical Trials Group, School of Oral and Dental Science, Lower Maudlin Street, University of Bristol, Bristol, BS1 2LY
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Effects of interleukin-1 beta injections into the subfornical organ and median preoptic nucleus on sodium appetite, blood pressure and body temperature of sodium-depleted rats. Physiol Behav 2016; 163:149-160. [DOI: 10.1016/j.physbeh.2016.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/14/2016] [Accepted: 05/04/2016] [Indexed: 01/01/2023]
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Wang L, Hiller H, Smith JA, de Kloet AD, Krause EG. Angiotensin type 1a receptors in the paraventricular nucleus of the hypothalamus control cardiovascular reactivity and anxiety-like behavior in male mice. Physiol Genomics 2016; 48:667-76. [PMID: 27468749 PMCID: PMC5111882 DOI: 10.1152/physiolgenomics.00029.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/13/2016] [Indexed: 01/19/2023] Open
Abstract
This study tested the hypothesis that deletion of angiotensin type 1a receptors (AT1a) from the paraventricular nucleus of hypothalamus (PVN) attenuates anxiety-like behavior, hypothalamic-pituitary-adrenal (HPA) axis activity, and cardiovascular reactivity. We used the Cre/LoxP system to generate male mice with AT1a specifically deleted from the PVN. Deletion of the AT1a from the PVN reduced anxiety-like behavior as indicated by increased time spent in the open arms of the elevated plus maze. In contrast, PVN AT1a deletion had no effect on HPA axis activation subsequent to an acute restraint challenge but did reduce hypothalamic mRNA expression for corticotropin-releasing hormone (CRH). To determine whether PVN AT1a deletion inhibits cardiovascular reactivity, we measured systolic blood pressure, heart rate, and heart rate variability (HRV) using telemetry and found that PVN AT1a deletion attenuated restraint-induced elevations in systolic blood pressure and elicited changes in HRV indicative of reduced sympathetic nervous activity. Consistent with the decreased HRV, PVN AT1a deletion also decreased adrenal weight, suggestive of decreased adrenal sympathetic outflow. Interestingly, the altered stress responsivity of mice with AT1a deleted from the PVN was associated with decreased hypothalamic microglia and proinflammatory cytokine expression. Collectively, these results suggest that deletion of AT1a from the PVN attenuates anxiety, CRH gene transcription, and cardiovascular reactivity and reduced brain inflammation may contribute to these effects.
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Affiliation(s)
- Lei Wang
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida; and
| | - Helmut Hiller
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida; and
| | - Justin A Smith
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida; and
| | - Annette D de Kloet
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, Florida
| | - Eric G Krause
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida; and
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Hiyama TY, Noda M. Sodium sensing in the subfornical organ and body-fluid homeostasis. Neurosci Res 2016; 113:1-11. [PMID: 27521454 DOI: 10.1016/j.neures.2016.07.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 07/22/2016] [Accepted: 07/28/2016] [Indexed: 01/28/2023]
Abstract
The brain monitors conditions of body fluids and levels of circulating neuroactive factors to maintain the systemic homeostasis. Unlike most regions in the brain, circumventricular organs (CVOs) lack the blood-brain barrier, and serve as the sensing center. Among the CVOs, the subfornical organ (SFO) is the sensing site of Na+ levels in body fluids to control water and salt intake. The SFO harbors neuronal cell bodies with a variety of hormone receptors and innervates many brain loci. In addition, the SFO harbors specialized glial cells (astrocytes and ependymal cells) expressing Nax, a Na+-level-sensitive sodium channel. These glial cells wrap a specific population of neurons with their processes, and control the firing activities of the neurons by gliotransmitters, such as lactate and epoxyeicosatrienoic acids (EETs), relevant to water/salt-intake behaviors. Recent advances in the understanding of physiological functions of the SFO are reviewed herein with a focus on the Na+-sensing mechanism by Nax.
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Affiliation(s)
- Takeshi Y Hiyama
- Division of Molecular Neurobiology, National Institute for Basic Biology, and School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan.
| | - Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology, and School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan
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Cornejo MP, Hentges ST, Maliqueo M, Coirini H, Becu-Villalobos D, Elias CF. Neuroendocrine Regulation of Metabolism. J Neuroendocrinol 2016; 28:10.1111/jne.12395. [PMID: 27114114 PMCID: PMC4956544 DOI: 10.1111/jne.12395] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/31/2016] [Accepted: 04/21/2016] [Indexed: 12/29/2022]
Abstract
Given the current environment in most developed countries, it is a challenge to maintain a good balance between calories consumed and calories burned, although maintenance of metabolic balance is key to good health. Therefore, understanding how metabolic regulation is achieved and how the dysregulation of metabolism affects health is an area of intense research. Most studies focus on the hypothalamus, which is a brain area that acts as a key regulator of metabolism. Among the nuclei that comprise the hypothalamus, the arcuate nucleus is one of the major mediators in the regulation of food intake. The regulation of energy balance is also a key factor ensuring the maintenance of any species as a result of the dependence of reproduction on energy stores. Adequate levels of energy reserves are necessary for the proper functioning of the hypothalamic-pituitary-gonadal axis. This review discusses valuable data presented in the 2015 edition of the International Workshop of Neuroendocrinology concerning the fundamental nature of the hormonal regulation of the hypothalamus and the impact on energy balance and reproduction.
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Affiliation(s)
- Maria P. Cornejo
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology [IMBICE, dependent on the Argentine Research Council (CONICET), Scientific Research Commission, Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], La Plata, Argentina
| | - Shane T. Hentges
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Manuel Maliqueo
- Endocrinology and Metabolism Laboratory, Department of Medicine West Division, School of Medicine University of Chile, Santiago de Chile, Chile
| | - Hector Coirini
- Laboratory of Neurobiology, Institute of Biology and Experimental Medicine [(IBYME), dependent on CONICET] and Department of Human Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
| | - Damasia Becu-Villalobos
- Laboratory of Pituitary Regulation, Institute of Biology and Experimental Medicine [(IBYME), dependent on CONICET], Buenos Aires, Argentina
| | - Carol F. Elias
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
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Weiss R, Bitton A, Ben Shimon M, Elhaik Goldman S, Nahary L, Cooper I, Benhar I, Pick CG, Chapman J. Annexin A2, autoimmunity, anxiety and depression. J Autoimmun 2016; 73:92-9. [PMID: 27372915 DOI: 10.1016/j.jaut.2016.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 06/21/2016] [Indexed: 01/01/2023]
Abstract
OBJECTIVES Antiphospholipid syndrome (APS) is associated with neurological manifestations and one of the novel autoantigens associated with this disease is Annexin A2 (ANXA2). In this work we have examined the effect of high levels of autoantibodies to ANXA2 on the brain in a mouse model. METHODS Recombinant ANXA2 emulsified in adjuvant was used to immunize mice while mice immunized with adjuvant only served as controls. At peak antibody levels the animal underwent behavioral and cognitive tests and their brains were examined for ANXA2 immunoglobulin G (IgG) and expression of ANXA2 and the closely linked protein p11. RESULTS Very high levels of anti-ANXA2 antibodies (Abs) were associated with reduced anxiety in the open field 13.14% ± 0.89% of the time in the center compared to 8.64% ± 0.91% observed in the control mice (p < 0.001 by t-test). A forced swim test found significantly less depression manifested by immobility in the ANXA2 group. The changes in behavior were accompanied by a significant reduction in serum corticosteroid levels of ANXA2 group compared to controls. Moreover, higher levels of total IgG and p11 expression were found in ANXA2 group brains. Lower levels of circulating anti-ANXA2 Abs were not associated with behavioral changes. CONCLUSIONS We have established an animal model with high levels of anti-ANXA2 Abs which induced IgG accumulation in the brain and specific anxiolytic and anti-depressive effects. This model promises to further our understanding of autoimmune disease such as APS and to provide better understanding of the role of the ANXA2-p11 complex in the brain.
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Affiliation(s)
- R Weiss
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel; Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - A Bitton
- Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel-Aviv, Israel
| | - M Ben Shimon
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - S Elhaik Goldman
- BBB-Group, The Joseph Sagol Neuroscience Center, Sheba Medical Center, Tel Hashomer, Ramat Gan, 52621, Israel
| | - L Nahary
- Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel-Aviv, Israel
| | - I Cooper
- BBB-Group, The Joseph Sagol Neuroscience Center, Sheba Medical Center, Tel Hashomer, Ramat Gan, 52621, Israel; The Interdisciplinary Center, Herzliya, Israel
| | - I Benhar
- Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel-Aviv, Israel
| | - C G Pick
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel; Department of Anatomy, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - J Chapman
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel; Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Department of Neurology, Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Hashomer, Israel; Robert and Martha Harden Chair in Mental and Neurological Diseases, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Bower RL, Eftekhari S, Waldvogel HJ, Faull RLM, Tajti J, Edvinsson L, Hay DL, Walker CS. Mapping the calcitonin receptor in human brain stem. Am J Physiol Regul Integr Comp Physiol 2016; 310:R788-93. [DOI: 10.1152/ajpregu.00539.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/05/2016] [Indexed: 11/22/2022]
Abstract
The calcitonin receptor (CTR) is relevant to three hormonal systems: amylin, calcitonin, and calcitonin gene-related peptide (CGRP). Receptors for amylin and calcitonin are targets for treating obesity, diabetes, and bone disorders. CGRP receptors represent a target for pain and migraine. Amylin receptors (AMY) are a heterodimer formed by the coexpression of CTR with receptor activity-modifying proteins (RAMPs). CTR with RAMP1 responds potently to both amylin and CGRP. The brain stem is a major site of action for circulating amylin and is a rich site of CGRP binding. This study aimed to enhance our understanding of these hormone systems by mapping CTR expression in the human brain stem, specifically the medulla oblongata. Widespread CTR-like immunoreactivity was observed throughout the medulla. Dense CTR staining was noted in several discrete nuclei, including the nucleus of the solitary tract, the hypoglossal nucleus, the cuneate nucleus, spinal trigeminal nucleus, the gracile nucleus, and the inferior olivary nucleus. CTR staining was also observed in the area postrema, the lateral reticular nucleus, and the pyramidal tract. The extensive expression of CTR in the medulla suggests that CTR may be involved in a wider range of functions than currently appreciated.
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Affiliation(s)
- Rebekah L. Bower
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Sajedeh Eftekhari
- Division of Experimental Vascular Research, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Henry J. Waldvogel
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
- Department of Anatomy with Medical Imaging, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand; and
| | - Richard L. M. Faull
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
- Department of Anatomy with Medical Imaging, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand; and
| | - János Tajti
- Department of Neurology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Lars Edvinsson
- Division of Experimental Vascular Research, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Debbie L. Hay
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Christopher S. Walker
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
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47
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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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48
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Tan DX, Manchester LC, Reiter RJ. CSF generation by pineal gland results in a robust melatonin circadian rhythm in the third ventricle as an unique light/dark signal. Med Hypotheses 2015; 86:3-9. [PMID: 26804589 DOI: 10.1016/j.mehy.2015.11.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 11/20/2015] [Indexed: 12/16/2022]
Abstract
Pineal gland is an important organ for the regulation of the bio-clock in all vertebrate species. Its major secretory product is melatonin which is considered as the chemical expression of darkness due to its circadian peak exclusively at night. Pineal melatonin can be either released into the blood stream or directly enter into the CSF of the third ventricle via the pineal recess. We have hypothesized that rather than the peripheral circulatory melatonin circadian rhythm serving as the light/dark signal, it is the melatonin rhythm in CSF of the third ventricle that serves this purpose. This is due to the fact that melatonin circadian rhythm in the CSF is more robust in terms of its extremely high concentration and its precise on/off peaks. Thus, extrapineal-generated melatonin or diet-derived melatonin which enters blood would not interfere with the bio-clock function of vertebrates. In addition, based on the relationship of the pineal gland to the CSF and the vascular structure of this gland, we also hypothesize that pineal gland is an essential player for CSF production. We feel it participates in both the formation and reabsorption of CSF. The mechanisms associated with these processes are reviewed and discussed in this brief review.
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Affiliation(s)
- Dun-Xian Tan
- Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, USA.
| | - Lucien C Manchester
- Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, USA
| | - Russel J Reiter
- Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, USA.
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49
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Hendricks BK, Cohen-Gadol AA, Miller JC. Novel delivery methods bypassing the blood-brain and blood-tumor barriers. Neurosurg Focus 2015; 38:E10. [PMID: 25727219 DOI: 10.3171/2015.1.focus14767] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Glioblastoma (GBM) is the most common primary brain tumor and carries a grave prognosis. Despite years of research investigating potentially new therapies for GBM, the median survival rate of individuals with this disease has remained fairly stagnant. Delivery of drugs to the tumor site is hampered by various barriers posed by the GBM pathological process and by the complex physiology of the blood-brain and blood-cerebrospinal fluid barriers. These anatomical and physiological barriers serve as a natural protection for the brain and preserve brain homeostasis, but they also have significantly limited the reach of intraparenchymal treatments in patients with GBM. In this article, the authors review the functional capabilities of the physical and physiological barriers that impede chemotherapy for GBM, with a specific focus on the pathological alterations of the blood-brain barrier (BBB) in this disease. They also provide an overview of current and future methods for circumventing these barriers in therapeutic interventions. Although ongoing research has yielded some potential options for future GBM therapies, delivery of chemotherapy medications across the BBB remains elusive and has limited the efficacy of these medications.
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Affiliation(s)
- Benjamin K Hendricks
- Goodman Campbell Brain and Spine, Indiana University Department of Neurological Surgery; and
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50
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Browning KN. Role of central vagal 5-HT3 receptors in gastrointestinal physiology and pathophysiology. Front Neurosci 2015; 9:413. [PMID: 26578870 PMCID: PMC4625078 DOI: 10.3389/fnins.2015.00413] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 10/15/2015] [Indexed: 12/21/2022] Open
Abstract
Vagal neurocircuits are vitally important in the co-ordination and modulation of GI reflexes and homeostatic functions. 5-hydroxytryptamine (5-HT; serotonin) is critically important in the regulation of several of these autonomic gastrointestinal (GI) functions including motility, secretion and visceral sensitivity. While several 5-HT receptors are involved in these physiological responses, the ligand-gated 5-HT3 receptor appears intimately involved in gut-brain signaling, particularly via the afferent (sensory) vagus nerve. 5-HT is released from enterochromaffin cells in response to mechanical or chemical stimulation of the GI tract which leads to activation of 5-HT3 receptors on the terminals of vagal afferents. 5-HT3 receptors are also present on the soma of vagal afferent neurons, including GI vagal afferent neurons, where they can be activated by circulating 5-HT. The central terminals of vagal afferents also exhibit 5-HT3 receptors that function to increase glutamatergic synaptic transmission to second order neurons of the nucleus tractus solitarius within the brainstem. While activation of central brainstem 5-HT3 receptors modulates visceral functions, it is still unclear whether central vagal neurons, i.e., nucleus of the tractus solitarius (NTS) and dorsal motor nucleus of the vagus (DMV) neurons themselves also display functional 5-HT3 receptors. Thus, activation of 5-HT3 receptors may modulate the excitability and activity of gastrointestinal vagal afferents at multiple sites and may be involved in several physiological and pathophysiological conditions, including distention- and chemical-evoked vagal reflexes, nausea, and vomiting, as well as visceral hypersensitivity.
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Affiliation(s)
- Kirsteen N Browning
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine Hershey, PA, USA
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