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Bischoff H, Kovach C, Kumar S, Bruss J, Tranel D, Khalsa SS. Sensing, feeling and regulating: investigating the association of focal brain damage with voluntary respiratory and motor control. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230251. [PMID: 39005040 DOI: 10.1098/rstb.2023.0251] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/26/2024] [Indexed: 07/16/2024] Open
Abstract
Breathing is a complex, vital function that can be modulated to influence physical and mental well-being. However, the role of cortical and subcortical brain regions in voluntary control of human respiration is underexplored. Here we investigated the influence of damage to human frontal, temporal or limbic regions on the sensation and regulation of breathing patterns. Participants performed a respiratory regulation task across regular and irregular frequencies ranging from 6 to 60 breaths per minute (bpm), with a counterbalanced hand motor control task. Interoceptive and affective states induced by each condition were assessed via questionnaire, and autonomic signals were indexed via skin conductance. Participants with focal lesions to the bilateral frontal lobe, right insula/basal ganglia and left medial temporal lobe showed reduced performance relative to individually matched healthy comparisons during the breathing and motor tasks. They also reported significantly higher anxiety during the 60 bpm regular and irregular breathing trials, with anxiety correlating with difficulty in rapid breathing specifically within this group. This study demonstrates that damage to frontal, temporal or limbic regions is associated with abnormal voluntary respiratory and motor regulation and tachypnoea-related anxiety, highlighting the role of the forebrain in affective and motor responses during breathing. This article is part of the theme issue 'Sensing and feeling: an integrative approach to sensory processing and emotional experience'.
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Affiliation(s)
- Henrik Bischoff
- Department of Psychology, University of Stockholm, 10691 Stockholm, Sweden
- Department of Psychology, Carl-von-Ossietzky University Oldenburg, 26129 Oldenburg, Germany
| | - Christopher Kovach
- Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
- Department of Neurosurgery, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Sukbhinder Kumar
- Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
| | - Joel Bruss
- Departments of Pediatrics, Neurology, and Psychiatry, University of Iowa, Iowa City, IA 52242, USA
| | - Daniel Tranel
- Departments of Neurology and Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Sahib S Khalsa
- Laureate Institute for Brain Research, Tulsa, OK 74136, USA
- Oxley College of Health Sciences, University of Tulsa, Tulsa, OK 74119, USA
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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Ramilevich Z, Zarroli K. Can intravenous lorazepam prevent postictal generalized EEG suppression? A case report. Clin Neurophysiol Pract 2024; 9:201-204. [PMID: 39055311 PMCID: PMC11269814 DOI: 10.1016/j.cnp.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 06/03/2024] [Accepted: 06/09/2024] [Indexed: 07/27/2024] Open
Abstract
Background Postictal generalized electrographic suppression (PGES) may be considered an electrophysiological marker associated with an increased risk of sudden unexplained death in epilepsy (SUDEP). Case Presentation A case study is presented whereby a young man with focal to bilateral tonic-clonic seizures exhibited PGES after two spontaneously-aborted seizures; yet, after a third benzodiazepine-aborted seizure, PGES was absent. Conclusion This suggests that acutely administered benzodiazepines may offer direct anti-suppressive effects to prevent PGES, potentially reducing SUDEP risk.
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Ricordeau F, Chouchou F, Pichot V, Roche F, Petitjean T, Gormand F, Bastuji H, Charbonnier E, Le Cam P, Stauffer E, Rheims S, Peter-Derex L. Impaired post-sleep apnea autonomic arousals in patients with drug-resistant epilepsy. Clin Neurophysiol 2024; 160:1-11. [PMID: 38367308 DOI: 10.1016/j.clinph.2024.02.003] [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: 09/09/2023] [Revised: 12/20/2023] [Accepted: 02/04/2024] [Indexed: 02/19/2024]
Abstract
OBJECTIVE Sudden and unexpected deaths in epilepsy (SUDEP) pathophysiology may involve an interaction between respiratory dysfunction and sleep/wake state regulation. We investigated whether patients with epilepsy exhibit impaired sleep apnea-related arousals. METHODS Patients with drug-resistant (N = 20) or drug-sensitive (N = 20) epilepsy and obstructive sleep apnea, as well as patients with sleep apnea but without epilepsy (controls, N = 20) were included. We explored (1) the respiratory arousal threshold based on nadir oxygen saturation, apnea-hypopnea index, and fraction of hypopnea among respiratory events; (2) the cardiac autonomic response to apnea/hypopnea quantified as percentages of changes from the baseline in RR intervals (RRI), high (HF) and low (LF) frequency powers, and LF/HF. RESULTS The respiratory arousal threshold did not differ between groups. At arousal onset, RRI decreased (-9.42%) and LF power (179%) and LF/HF ratio (190%) increased. This was followed by an increase in HF power (118%), p < 0.05. The RRI decrease was lower in drug-resistant (-7.40%) than in drug-sensitive patients (-9.94%) and controls (-10.91%), p < 0.05. LF and HF power increases were higher in drug-resistant (188%/126%) than in drug-sensitive patients (172%/126%) and controls (177%/115%), p < 0.05. CONCLUSIONS Cardiac reactivity following sleep apnea is impaired in drug-resistant epilepsy. SIGNIFICANCE This autonomic dysfunction might contribute to SUDEP pathophysiology.
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Affiliation(s)
- François Ricordeau
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France; Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Lyon, France
| | - Florian Chouchou
- IRISSE Laboratory (EA4075), UFR SHE, University of La Réunion, Le Tampon, France
| | - Vincent Pichot
- SAINBIOSE, INSERM U1059, Saint-Etienne Jean-Monnet University, Mines Saint-Etienne, France; Clinical Physiology and Exercise, Visas Center, Saint Etienne University Hospital, France
| | - Frédéric Roche
- SAINBIOSE, INSERM U1059, Saint-Etienne Jean-Monnet University, Mines Saint-Etienne, France; Clinical Physiology and Exercise, Visas Center, Saint Etienne University Hospital, France
| | - Thierry Petitjean
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France
| | - Frédéric Gormand
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France
| | - Hélène Bastuji
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France; Lyon Neuroscience Research Center, CNRS UMR 5292 / INSERM U1028 and Lyon 1 University, Lyon, France
| | - Eléna Charbonnier
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France
| | - Pierre Le Cam
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France
| | - Emeric Stauffer
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France; Inter-university Laboratoryof Human MovementBiology (LIBM) EA7424, Team « Vascular Biology and Red Blood Cell », Lyon 1 University, Lyon, France; Respiratory Functional Investigation & Physical Activity Department, Hospices Civils de Lyon, Lyon, France
| | - Sylvain Rheims
- Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Lyon, France; Lyon Neuroscience Research Center, CNRS UMR 5292 / INSERM U1028 and Lyon 1 University, Lyon, France; Lyon 1 University, Lyon, France
| | - Laure Peter-Derex
- Centre for Sleep Medicine and Respiratory Diseases, Hospices Civils de Lyon, Lyon, France; Lyon Neuroscience Research Center, CNRS UMR 5292 / INSERM U1028 and Lyon 1 University, Lyon, France; Lyon 1 University, Lyon, France.
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Fraile-Martinez O, García-Montero C, Díez SC, Bravo C, Quintana-Coronado MDG, Lopez-Gonzalez L, Barrena-Blázquez S, García-Honduvilla N, De León-Luis JA, Rodriguez-Martín S, Saez MA, Alvarez-Mon M, Diaz-Pedrero R, Ortega MA. Sudden Infant Death Syndrome (SIDS): State of the Art and Future Directions. Int J Med Sci 2024; 21:848-861. [PMID: 38617004 PMCID: PMC11008475 DOI: 10.7150/ijms.89490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 02/10/2024] [Indexed: 04/16/2024] Open
Abstract
Sudden infant death syndrome (SIDS) is a type of death that occurs suddenly and without any apparent explanation, affecting infants between 28 days of life and up to a year. Recognition of this entity includes performing an autopsy to determine if there is another explanation for the event and performing both an external and internal examination of the different tissues to search for possible histopathological findings. Despite the relative success of awareness campaigns and the implementation of prevention measures, SIDS still represents one of the leading causes of death among infants worldwide. In addition, although the development of different techniques has made it possible to make significant progress in the characterization of the etiopathogenic mechanisms underlying SIDS, there are still many unknowns to be resolved in this regard and the integrative consideration of this syndrome represents an enormous challenge to face both from a point of view scientific and medical view as humanitarian. For all these reasons, this paper aims to summarize the most relevant current knowledge of SIDS, exploring from the base the characterization and recognition of this condition, its forensic findings, its risk factors, and the main prevention measures to be implemented. Likewise, an attempt will be made to analyze the causes and pathological mechanisms associated with SIDS, as well as potential approaches and future paths that must be followed to reduce the impact of this condition.
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Affiliation(s)
- Oscar Fraile-Martinez
- Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcalá de Henares, Spain
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
| | - Cielo García-Montero
- Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcalá de Henares, Spain
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
| | - Sofía Castellanos Díez
- Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcalá de Henares, Spain
| | - Coral Bravo
- Department of Public and Maternal and Child Health, School of Medicine, Complutense University of Madrid, 28040 Madrid, Spain
- Department of Obstetrics and Gynecology, University Hospital Gregorio Marañón, 28009 Madrid, Spain
- Health Research Institute Gregorio Marañón, 28009 Madrid, Spain
| | - María de Guadalupe Quintana-Coronado
- Department of Public and Maternal and Child Health, School of Medicine, Complutense University of Madrid, 28040 Madrid, Spain
- Department of Obstetrics and Gynecology, University Hospital Gregorio Marañón, 28009 Madrid, Spain
- Health Research Institute Gregorio Marañón, 28009 Madrid, Spain
| | - Laura Lopez-Gonzalez
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
- Department of Surgery, Medical and Social Sciences, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcala de Henares, Spain
| | - Silvestra Barrena-Blázquez
- Department of General and Digestive Surgery, University Hospital Príncipe de Asturias, 28805 Madrid, Spain
- Department of Nursing and Physiotherapy, Faculty of Medicine and Health Sciences, University of Alcalá, Alcalá de Henares, Spain
| | - Natalio García-Honduvilla
- Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcalá de Henares, Spain
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
| | - Juan A. De León-Luis
- Department of Public and Maternal and Child Health, School of Medicine, Complutense University of Madrid, 28040 Madrid, Spain
- Department of Obstetrics and Gynecology, University Hospital Gregorio Marañón, 28009 Madrid, Spain
- Health Research Institute Gregorio Marañón, 28009 Madrid, Spain
| | - Sonia Rodriguez-Martín
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
- Service of Pediatric, Hospital Universitario Principe de Asturias, 28801 Alcalá de Henares, Spain
| | - Miguel A Saez
- Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcalá de Henares, Spain
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
- Pathological Anatomy Service, Central University Hospital of Defence-UAH Madrid, 28801 Alcala de Henares, Spain
| | - Melchor Alvarez-Mon
- Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcalá de Henares, Spain
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
- Immune System Diseases-Rheumatology and Internal Medicine Service, University Hospital Príncipe de Asturias, CIBEREHD, 28806 Alcalá de Henares, Spain
| | - Raul Diaz-Pedrero
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
- Department of Surgery, Medical and Social Sciences, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcala de Henares, Spain
- Department of General and Digestive Surgery, University Hospital Príncipe de Asturias, 28805 Madrid, Spain
| | - Miguel A Ortega
- Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá, 28801 Alcalá de Henares, Spain
- Ramón y Cajal Institute of Sanitary Research (IRYCIS), 28034 Madrid, Spain
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Petrucci AN, Jones AR, Kreitlow BL, Buchanan GF. Peri-ictal activation of dorsomedial dorsal raphe serotonin neurons reduces mortality associated with maximal electroshock seizures. Brain Commun 2024; 6:fcae052. [PMID: 38487550 PMCID: PMC10939444 DOI: 10.1093/braincomms/fcae052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 12/13/2023] [Accepted: 03/08/2024] [Indexed: 03/17/2024] Open
Abstract
Over one-third of patients with epilepsy will develop refractory epilepsy and continue to experience seizures despite medical treatment. These patients are at the greatest risk for sudden unexpected death in epilepsy. The precise mechanisms underlying sudden unexpected death in epilepsy are unknown, but cardiorespiratory dysfunction and arousal impairment have been implicated. Substantial circumstantial evidence suggests serotonin is relevant to sudden unexpected death in epilepsy as it modulates sleep/wake regulation, breathing and arousal. The dorsal raphe nucleus is a major serotonergic center and a component of the ascending arousal system. Seizures disrupt the firing of dorsal raphe neurons, which may contribute to reduced responsiveness. However, the relevance of the dorsal raphe nucleus and its subnuclei to sudden unexpected death in epilepsy remains unclear. The dorsomedial dorsal raphe may be a salient target due to its role in stress and its connections with structures implicated in sudden unexpected death in epilepsy. We hypothesized that optogenetic activation of dorsomedial dorsal raphe serotonin neurons in TPH2-ChR2-YFP (n = 26) mice and wild-type (n = 27) littermates before induction of a maximal electroshock seizure would reduce mortality. In this study, pre-seizure activation of dorsal raphe nucleus serotonin neurons reduced mortality in TPH2-ChR2-YFP mice with implants aimed at the dorsomedial dorsal raphe. These results implicate the dorsomedial dorsal raphe in this novel circuit influencing seizure-induced mortality. It is our hope that these results and future experiments will define circuit mechanisms that could ultimately reduce sudden unexpected death in epilepsy.
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Affiliation(s)
- Alexandra N Petrucci
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Allysa R Jones
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Benjamin L Kreitlow
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Gordon F Buchanan
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Cummings KJ, Leiter JC, Trachtenberg FL, Okaty BW, Darnall RA, Haas EA, Harper RM, Nattie EE, Krous HF, Mena OJ, Richerson GB, Dymecki SM, Kinney HC, Haynes RL. Altered 5-HT2A/C receptor binding in the medulla oblongata in the sudden infant death syndrome (SIDS): Part II. Age-associated alterations in serotonin receptor binding profiles within medullary nuclei supporting cardiorespiratory homeostasis. J Neuropathol Exp Neurol 2024; 83:144-160. [PMID: 38323418 PMCID: PMC10880067 DOI: 10.1093/jnen/nlae004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024] Open
Abstract
The failure of chemoreflexes, arousal, and/or autoresuscitation to asphyxia may underlie some sudden infant death syndrome (SIDS) cases. In Part I, we showed that some SIDS infants had altered 5-hydroxytryptamine (5-HT)2A/C receptor binding in medullary nuclei supporting chemoreflexes, arousal, and autoresuscitation. Here, using the same dataset, we tested the hypotheses that the prevalence of low 5-HT1A and/or 5-HT2A/C receptor binding (defined as levels below the 95% confidence interval of controls-a new approach), and the percentages of nuclei affected are greater in SIDS versus controls, and that the distribution of low binding varied with age of death. The prevalence and percentage of nuclei with low 5-HT1A and 5-HT2A/C binding in SIDS were twice that of controls. The percentage of nuclei with low 5-HT2A/C binding was greater in older SIDS infants. In >80% of older SIDS infants, low 5-HT2A/C binding characterized the hypoglossal nucleus, vagal dorsal nucleus, nucleus of solitary tract, and nuclei of the olivocerebellar subnetwork (important for blood pressure regulation). Together, our findings from SIDS infants and from animal models of serotonergic dysfunction suggest that some SIDS cases represent a serotonopathy. We present new hypotheses, yet to be tested, about how defects within serotonergic subnetworks may lead to SIDS.
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Affiliation(s)
- Kevin J Cummings
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - James C Leiter
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | | | - Benjamin W Okaty
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Robert A Darnall
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Elisabeth A Haas
- Department of Research, Rady’s Children’s Hospital, San Diego, California, USA
| | - Ronald M Harper
- Department of Neurobiology and the Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Eugene E Nattie
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Henry F Krous
- Department of Pediatrics, University of California San Diego, San Diego, California, USA
- Departments of Pathology and Pediatrics, Rady Children’s Hospital, San Diego, California, USA
| | - Othon J Mena
- San Diego County Medical Examiner Office, San Diego, California, USA
| | - George B Richerson
- Departments of Neurology and Molecular Physiology & Biophysics, University of Iowa, Iowa City, Iowa, USA
| | - Susan M Dymecki
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Hannah C Kinney
- Department of Pathology, CJ Murphy Laboratory for SIDS Research, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Robin L Haynes
- Department of Pathology, CJ Murphy Laboratory for SIDS Research, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Bischoff H, Kovach C, Kumar S, Bruss J, Tranel D, Khalsa SS. Sensing, Feeling, and Regulating: Investigating the Association of Focal Brain Damage with Voluntary Respiratory and Motor Control. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.16.562254. [PMID: 37905134 PMCID: PMC10614780 DOI: 10.1101/2023.10.16.562254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Breathing is a complex, vital function that can be modulated to influence physical and mental well-being. However, the role of cortical and subcortical brain regions in voluntary control of human respiration is underexplored. Here we investigated the influence of damage to human frontal, temporal, or limbic regions on the sensation and regulation of breathing patterns. Participants performed a respiratory regulation task across regular and irregular frequencies ranging from 6 to 60 breaths per minute (bpm), with a counterbalanced hand motor control task. Interoceptive and affective states induced by each condition were assessed via questionnaire and autonomic signals were indexed via skin conductance. Participants with focal lesions to the bilateral frontal lobe, right insula/basal ganglia, and left medial temporal lobe showed reduced performance than individually matched healthy comparisons during the breathing and motor tasks. They also reported significantly higher anxiety during the 60-bpm regular and irregular breathing trials, with anxiety correlating with difficulty in rapid breathing specifically within this group. This study demonstrates that damage to frontal, temporal, or limbic regions is associated with abnormal voluntary respiratory and motor regulation and tachypnea-related anxiety, highlighting the role of the forebrain in affective and motor responses during breathing. Highlights Impaired human respiratory regulation is associated with cortical/subcortical brain lesionsFrontolimbic/temporal regions contribute to rhythmic breathing and hand motor controlFrontolimbic/temporal damage is associated with anxiety during tachypnea/irregular breathingThe human forebrain is vital for affective and interoceptive experiences during breathing.
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Buerki SE, Haas C, Neubauer J. Exome analysis focusing on epilepsy-related genes in children and adults with sudden unexplained death. Seizure 2023; 113:66-75. [PMID: 37995443 DOI: 10.1016/j.seizure.2023.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/25/2023] Open
Abstract
PURPOSE Genetic studies in sudden infant death syndrome (SIDS) and sudden unexplained death (SUD) cohorts have indicated that cardiovascular diseases might have contributed to sudden unexpected death in 20-35 % of autopsy-negative cases. Sudden unexpected death can also occur in people with epilepsy, termed as sudden unexpected death in epilepsy (SUDEP). The pathophysiological mechanisms of SUDEP are not well understood, but are likely multifactorial, including seizure-induced hypoventilation and arrhythmias as well as genetic risk factors. The sudden death of some of the SIDS/SUD victims might also be explained by genetic epilepsy, therefore this study aimed to expand the post-mortem genetic analysis of SIDS/SUD cases to epilepsy-related genes. METHODS Existing whole-exome sequencing data from our 155 SIDS and 45 SUD cases were analyzed, with a focus on 365 epilepsy-related genes. Nine of the SUD victims had a known medical history of epilepsy, seizures or other underlying neurological conditions and were therefore classified as SUDEP cases. RESULTS In our SIDS and SUD cohorts, we found epilepsy-related pathogenic/likely pathogenic variants in the genes OPA1, RAI1, SCN3A, SCN5A and TSC2. CONCLUSION Post-mortem analysis of epilepsy-related genes identified potentially disease-causing variants that might have contributed to the sudden death events in our SIDS/SUD cases. However, the interpretation of identified variants remains challenging and often changes over time as more data is gathered. Overall, this study contributes insight in potentially pathophysiological epilepsy-related mechanisms in SIDS, SUD and SUDEP victims and underlines the importance of sensible counselling on the risk and preventive measures in genetic epilepsy.
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Affiliation(s)
- Sarah E Buerki
- Department of Neuropediatrics, University Children's Hospital Zurich, Switzerland
| | - Cordula Haas
- Zurich Institute of Forensic Medicine, University of Zurich, Switzerland.
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Kinkead R, Ambrozio-Marques D, Fournier S, Gagnon M, Guay LM. Estrogens, age, and, neonatal stress: panic disorders and novel views on the contribution of non-medullary structures to respiratory control and CO 2 responses. Front Physiol 2023; 14:1183933. [PMID: 37265841 PMCID: PMC10229816 DOI: 10.3389/fphys.2023.1183933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 04/21/2023] [Indexed: 06/03/2023] Open
Abstract
CO2 is a fundamental component of living matter. This chemical signal requires close monitoring to ensure proper match between metabolic production and elimination by lung ventilation. Besides ventilatory adjustments, CO2 can also trigger innate behavioral and physiological responses associated with fear and escape but the changes in brain CO2/pH required to induce ventilatory adjustments are generally lower than those evoking fear and escape. However, for patients suffering from panic disorder (PD), the thresholds for CO2-evoked hyperventilation, fear and escape are reduced and the magnitude of those reactions are excessive. To explain these clinical observations, Klein proposed the false suffocation alarm hypothesis which states that many spontaneous panics occur when the brain's suffocation monitor erroneously signals a lack of useful air, thereby maladaptively triggering an evolved suffocation alarm system. After 30 years of basic and clinical research, it is now well established that anomalies in respiratory control (including the CO2 sensing system) are key to PD. Here, we explore how a stress-related affective disorder such as PD can disrupt respiratory control. We discuss rodent models of PD as the concepts emerging from this research has influenced our comprehension of the CO2 chemosensitivity network, especially structure that are not located in the medulla, and how factors such as stress and biological sex modulate its functionality. Thus, elucidating why hormonal fluctuations can lead to excessive responsiveness to CO2 offers a unique opportunity to gain insights into the neuroendocrine mechanisms regulating this key aspect of respiratory control and the pathophysiology of respiratory manifestations of PD.
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Abstract
PURPOSE OF REVIEW Sudden unexpected death in epilepsy (SUDEP) is a leading cause of death in patients with epilepsy. This review highlights the recent literature regarding epidemiology on a global scale, putative mechanisms and thoughts towards intervention and prevention. RECENT FINDINGS Recently, numerous population-based studies have examined the incidence of SUDEP in many countries. Remarkably, incidence is quite consistent across these studies, and is commensurate with the recent estimates of about 1.2 per 1000 patient years. These studies further continue to support that incidence is similar across the ages and that comparable factors portend heightened risk for SUDEP. Fervent research in patients and animal studies continues to hone the understanding of potential mechanisms for SUDEP, especially those regarding seizure-induced respiratory dysregulation. Many of these studies and others have begun to lay out a path towards identification of improved treatment and prevention means. However, continued efforts are needed to educate medical professionals about SUDEP risk and the need to disclose this to patients. SUMMARY SUDEP is a devastating potential outcome of epilepsy. More is continually learned about risk and mechanisms from clinical and preclinical studies. This knowledge can hopefully be leveraged into preventive measures in the near future.
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Affiliation(s)
- Gordon F Buchanan
- Department of Neurology
- Neuroscience Graduate Program
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Ana T Novella Maciel
- Department of Neurology
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Universidad Nacional Autónoma de México, Mexico City, México
| | - Matthew J Summerfield
- Neuroscience Graduate Program
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Huang TH, Lai MC, Chen YS, Huang CW. The Roles of Glutamate Receptors and Their Antagonists in Status Epilepticus, Refractory Status Epilepticus, and Super-Refractory Status Epilepticus. Biomedicines 2023; 11:biomedicines11030686. [PMID: 36979664 PMCID: PMC10045490 DOI: 10.3390/biomedicines11030686] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/18/2023] [Accepted: 02/21/2023] [Indexed: 03/30/2023] Open
Abstract
Status epilepticus (SE) is a neurological emergency with a high mortality rate. When compared to chronic epilepsy, it is distinguished by the durability of seizures and frequent resistance to benzodiazepine (BZD). The Receptor Trafficking Hypothesis, which suggests that the downregulation of γ-Aminobutyric acid type A (GABAA) receptors, and upregulation of N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors play major roles in the establishment of SE is the most widely accepted hypothesis underlying BZD resistance. NMDA and AMPA are ionotropic glutamate receptor families that have important excitatory roles in the central nervous system (CNS). They are both essential in maintaining the normal function of the brain and are involved in a variety of neuropsychiatric diseases, including epilepsy. Based on animal and human studies, antagonists of NMDA and AMPA receptors have a significant impact in ending SE; albeit most of them are not yet approved to be in clinically therapeutic guidelines, due to their psychomimetic adverse effects. Although there is still a dearth of randomized, prospective research, NMDA antagonists such as ketamine, magnesium sulfate, and the AMPA antagonist, perampanel, are regarded to be reasonable optional adjuvant therapies in controlling SE, refractory SE (RSE) or super-refractory SE (SRSE), though there are still a lack of randomized, prospective studies. This review seeks to summarize and update knowledge on the SE development hypothesis, as well as clinical trials using NMDA and AMPA antagonists in animal and human studies of SE investigations.
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Affiliation(s)
- Tzu-Hsin Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70142, Taiwan
- Zhengxin Neurology & Rehabilitation Center, Tainan 70459, Taiwan
| | - Ming-Chi Lai
- Department of Pediatrics, Chi-Mei Medical Center, Tainan 71004, Taiwan
| | - Yu-Shiue Chen
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70142, Taiwan
| | - Chin-Wei Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70142, Taiwan
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12
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Bauer J, Devinsky O, Rothermel M, Koch H. Autonomic dysfunction in epilepsy mouse models with implications for SUDEP research. Front Neurol 2023; 13:1040648. [PMID: 36686527 PMCID: PMC9853197 DOI: 10.3389/fneur.2022.1040648] [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: 09/09/2022] [Accepted: 12/12/2022] [Indexed: 01/09/2023] Open
Abstract
Epilepsy has a high prevalence and can severely impair quality of life and increase the risk of premature death. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in drug-resistant epilepsy and most often results from respiratory and cardiac impairments due to brainstem dysfunction. Epileptic activity can spread widely, influencing neuronal activity in regions outside the epileptic network. The brainstem controls cardiorespiratory activity and arousal and reciprocally connects to cortical, diencephalic, and spinal cord areas. Epileptic activity can propagate trans-synaptically or via spreading depression (SD) to alter brainstem functions and cause cardiorespiratory dysfunction. The mechanisms by which seizures propagate to or otherwise impair brainstem function and trigger the cascading effects that cause SUDEP are poorly understood. We review insights from mouse models combined with new techniques to understand the pathophysiology of epilepsy and SUDEP. These techniques include in vivo, ex vivo, invasive and non-invasive methods in anesthetized and awake mice. Optogenetics combined with electrophysiological and optical manipulation and recording methods offer unique opportunities to study neuronal mechanisms under normal conditions, during and after non-fatal seizures, and in SUDEP. These combined approaches can advance our understanding of brainstem pathophysiology associated with seizures and SUDEP and may suggest strategies to prevent SUDEP.
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Affiliation(s)
- Jennifer Bauer
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany,Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Orrin Devinsky
- Departments of Neurology, Neurosurgery and Psychiatry, NYU Langone School of Medicine, New York, NY, United States
| | - Markus Rothermel
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Henner Koch
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany,*Correspondence: Henner Koch ✉
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13
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Gu B, Adeli H. Toward automated prediction of sudden unexpected death in epilepsy. Rev Neurosci 2022; 33:877-887. [PMID: 35619127 DOI: 10.1515/revneuro-2022-0024] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/19/2022] [Indexed: 12/14/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a devastating yet overlooked complication of epilepsy. The rare and complex nature of SUDEP makes it challenging to study. No prediction or prevention of SUDEP is currently available in a clinical setting. In the past decade, significant advances have been made in our knowledge of the pathophysiologic cascades that lead to SUDEP. In particular, studies of brain, heart, and respiratory functions in both human patients at the epilepsy monitoring unit and animal models during fatal seizures provide critical information to integrate computational tools for SUDEP prediction. The rapid advances in automated seizure detection and prediction algorithms provide a fundamental framework for their adaption in predicting SUDEP. If a SUDEP can be predicted, then there will be a potential for medical intervention to be administered, either by their caregivers or via an implanted device automatically delivering electrical stimulation or medication, and finally save lives from fatal seizures. This article presents recent developments of SUDEP studies focusing on the pathophysiologic basis of SUDEP and computational implications of machine learning techniques that can be adapted and extended for SUDEP prediction. This article also discusses some novel ideas for SUDEP prediction and rescue including principal component analysis and closed-loop intervention.
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Affiliation(s)
- Bin Gu
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA
| | - Hojjat Adeli
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA.,Department of Biomedical Informatics, Ohio State University, Columbus, OH 43210, USA
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14
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Genes involved in paediatric apnoea and death based on knockout animal models: Implications for sudden infant death syndrome (SIDS). Paediatr Respir Rev 2022; 44:53-60. [PMID: 34750067 DOI: 10.1016/j.prrv.2021.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 09/14/2021] [Indexed: 12/14/2022]
Abstract
The mechanism of death in Sudden infant death syndrome (SIDS) remains unknown but it is hypothesised that cardiorespiratory failure of brainstem origin results in early post-natal death. For a subset of SIDS infants, an underlying genetic cause may be present, and genetic abnormalities affecting brainstem respiratory control may result in abnormalities that are detectable before death. Genetic knockout mice models were developed in the 1990s and have since helped to elucidate the physiological roles of a number of genes. This systematic review aimed to identify which genes, when knocked out, result in the phenotypes of abnormal cardiorespiratory control and/or early post-natal death. Three major genes were identified: Pet1- a serotonin transcription factor, the neurotrophin pituitary adenylate cyclase activating polypeptide (PACAP) and its receptor (PAC1). Knockouts targeting these genes had blunted hypercapnic and/or hypoxic responses and early post-natal death. The hypothesis that these genes have a role in SIDS is supported by their being identified as abnormal in SIDS cohorts. Future research in SIDS cohorts will be important to determine whether these genetic abnormalities coexist and their potential applicability as biomarkers.
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15
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Sveinsson O, Andersson T, Carlsson S, Tomson T. Perinatal risk factors for SUDEP: A population-based case-control study. Epilepsia 2022; 63:e119-e124. [PMID: 35778907 DOI: 10.1111/epi.17354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 06/14/2022] [Accepted: 06/29/2022] [Indexed: 01/07/2023]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a leading epilepsy-related cause of death. Researchers have highlighted the similarities between SUDEP and sudden infant death syndrome (SIDS), but perinatal risk factors such as those identified for SIDS have not been assessed previously for SUDEP. We conducted a population-based case-control study of 58 SUDEP individuals and 384 living epilepsy controls born after 1982, utilizing the Swedish Medical Birth Register together with other national health registers and individual medical records to examine if prenatal and perinatal factors are associated with SUDEP risk. We observed a 3-fold SUDEP risk increase for infants who were small for gestational age (SGA) (odds ratio [OR] 3.13; 95% confidence interval [CI] 1.05-9.30) and for those with an Apgar score of 0-6 compared to 9-10 at 10 min (OR 3.22; 95% CI 1.05-9.87). After adjusting for a number of known SUDEP risk factors, we observed that the Apgar score between 0 and 6 after 10 min had a 10-fold increased risk for SUDEP OR 10.37 (95% CI 1.49-72.01) and over a 2-fold risk for those born after the 40th gestational week (OR 2.42; 95% CI 1.03-5.65). The potential mechanisms linking low Apgar score, gestational age, and SGA to SUDEP risk remain to be explored.
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Affiliation(s)
- Olafur Sveinsson
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,University Iceland, Faculty of Medicine, Reykjavik, Iceland
| | - Tomas Andersson
- Center for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden.,Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Sofia Carlsson
- Center for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden
| | - Torbjörn Tomson
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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16
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Joyal KG, Kreitlow BL, Buchanan GF. The role of sleep state and time of day in modulating breathing in epilepsy: implications for sudden unexpected death in epilepsy. Front Neural Circuits 2022; 16:983211. [PMID: 36082111 PMCID: PMC9445500 DOI: 10.3389/fncir.2022.983211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among patients with refractory epilepsy. While the exact etiology of SUDEP is unknown, mounting evidence implicates respiratory dysfunction as a precipitating factor in cases of seizure-induced death. Dysregulation of breathing can occur in epilepsy patients during and after seizures as well as interictally, with many epilepsy patients exhibiting sleep-disordered breathing (SDB), such as obstructive sleep apnea (OSA). The majority of SUDEP cases occur during the night, with the victim found prone in or near a bed. As breathing is modulated in both a time-of-day and sleep state-dependent manner, it is relevant to examine the added burden of nocturnal seizures on respiratory function. This review explores the current state of understanding of the relationship between respiratory function, sleep state and time of day, and epilepsy. We highlight sleep as a particularly vulnerable period for individuals with epilepsy and press that this topic warrants further investigation in order to develop therapeutic interventions to mitigate the risk of SUDEP.
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Affiliation(s)
- Katelyn G. Joyal
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Benjamin L. Kreitlow
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Medical Scientist Training Program, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gordon F. Buchanan
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Medical Scientist Training Program, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- *Correspondence: Gordon F. Buchanan
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17
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Collard R, Aziz MC, Rapp K, Cutshall C, Duyvesteyn E, Metcalf CS. Galanin analogs prevent mortality from seizure-induced respiratory arrest in mice. Front Neural Circuits 2022; 16:901334. [PMID: 36051473 PMCID: PMC9425456 DOI: 10.3389/fncir.2022.901334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
ObjectiveSudden Unexpected Death in Epilepsy (SUDEP) accounts for 20% of mortality in those with recurrent seizures. While risk factors, monitoring systems, and standard practices are in place, the pathophysiology of SUDEP is still not well understood. Better knowledge of SUDEP and its potential mechanisms of action is crucial to reducing risk in this patient population and developing potential treatment options. Clinical studies and animal models of SUDEP suggest that diminished post-ictal respiratory control may be the dominant mechanism contributing to mortality. Recently, it was demonstrated that the depletion of the neuropeptide galanin in the amygdala occurs in human SUDEP. The amygdala plays a key role in the central integration of respiratory signaling; the depletion of galanin may represent a critical change that predisposes individuals to SUDEP.Materials and methodsTo evaluate the impact of enhancing galaninergic signaling to potentially protect against SUDEP, we studied seizure-induced respiratory arrest (S-IRA) following central (intracerebroventricular, intra-amygdala) and systemic (intraperitoneal, subcutaneous) administration of galanin analogs. Seizure naïve and seizure experienced (fully kindled) mice were tested.ResultsCentral and systemically administered galanin analogs protect against S-IRA in naïve C57Bl/6J mice. Differential efficacy between receptor subtype-selective analogs varied based on the route of administration. Sub-chronic systemic administration at doses that reduced 6 Hz seizures also protected against S-IRA. Acute treatment benefits also extended to fully kindled mice experiencing tonic extension.SignificanceThese data demonstrate that galanin analogs may be protective against post-ictal respiratory collapse.
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Affiliation(s)
- Ryley Collard
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Miriam C. Aziz
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Kevin Rapp
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Connor Cutshall
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Evalien Duyvesteyn
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
| | - Cameron S. Metcalf
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
- Epilepsy Therapy Screening Program Contract Site, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, United States
- *Correspondence: Cameron S. Metcalf,
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18
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Mouradian GC, Liu P, Nakagawa P, Duffy E, Gomez Vargas J, Balapattabi K, Grobe JL, Sigmund CD, Hodges MR. Patch-to-Seq and Transcriptomic Analyses Yield Molecular Markers of Functionally Distinct Brainstem Serotonin Neurons. Front Synaptic Neurosci 2022; 14:910820. [PMID: 35844900 PMCID: PMC9280690 DOI: 10.3389/fnsyn.2022.910820] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/10/2022] [Indexed: 01/22/2023] Open
Abstract
Acute regulation of CO2 and pH homeostasis requires sensory feedback from peripheral (carotid body) and central (central) CO2/pH sensitive cells - so called respiratory chemoreceptors. Subsets of brainstem serotonin (5-HT) neurons in the medullary raphe are CO2 sensitive or insensitive based on differences in embryonic origin, suggesting these functionally distinct subpopulations may have unique transcriptional profiles. Here, we used Patch-to-Seq to determine if the CO2 responses in brainstem 5-HT neurons could be correlated to unique transcriptional profiles and/or unique molecular markers and pathways. First, firing rate changes with hypercapnic acidosis were measured in fluorescently labeled 5-HT neurons in acute brainstem slices from transgenic, Dahl SS (SSMcwi) rats expressing T2/ePet-eGFP transgene in Pet-1 expressing (serotonin) neurons (SS ePet1-eGFP rats). Subsequently, the transcriptomic and pathway profiles of CO2 sensitive and insensitive 5-HT neurons were determined and compared by single cell RNA (scRNAseq) and bioinformatic analyses. Low baseline firing rates were a distinguishing feature of CO2 sensitive 5-HT neurons. scRNAseq of these recorded neurons revealed 166 differentially expressed genes among CO2 sensitive and insensitive 5-HT neurons. Pathway analyses yielded novel predicted upstream regulators, including the transcription factor Egr2 and Leptin. Additional bioinformatic analyses identified 6 candidate gene markers of CO2 sensitive 5-HT neurons, and 2 selected candidate genes (CD46 and Iba57) were both expressed in 5-HT neurons determined via in situ mRNA hybridization. Together, these data provide novel insights into the transcriptional control of cellular chemoreception and provide unbiased candidate gene markers of CO2 sensitive 5-HT neurons. Methodologically, these data highlight the utility of the patch-to-seq technique in enabling the linkage of gene expression to specific functions, like CO2 chemoreception, in a single cell to identify potential mechanisms underlying functional differences in otherwise similar cell types.
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Affiliation(s)
- Gary C. Mouradian
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States,Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, United States,*Correspondence: Gary C. Mouradian Jr.,
| | - Pengyuan Liu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Pablo Nakagawa
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Erin Duffy
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Javier Gomez Vargas
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Kirthikaa Balapattabi
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Justin L. Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States,Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, United States,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States,Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, United States,Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Curt D. Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States,Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, United States,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Matthew R. Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States,Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, United States
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Gu L, Yu Q, Shen Y, Wang Y, Xu Q, Zhang H. The role of monoaminergic neurons in modulating respiration during sleep and the connection with SUDEP. Biomed Pharmacother 2022; 150:112983. [PMID: 35453009 DOI: 10.1016/j.biopha.2022.112983] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/04/2022] [Accepted: 04/14/2022] [Indexed: 11/25/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among epilepsy patients, occurring even more frequently in cases with anti-epileptic drug resistance. Despite some advancements in characterizing SUDEP, the underlying mechanism remains incompletely understood. This review summarizes the latest advances in our understanding of the pathogenic mechanisms of SUDEP, in order to identify possible targets for the development of new strategies to prevent SUDEP. Based on our previous research along with the current literature, we focus on the role of sleep-disordered breathing (SDB) and its related neural mechanisms to consider the possible roles of monoaminergic neurons in the modulation of respiration during sleep and the occurrence of SUDEP. Overall, this review suggests that targeting the monoaminergic neurons is a promising approach to preventing SUDEP. The proposed roles of SDB and related monoaminergic neural mechanisms in SUDEP provide new insights for explaining the pathogenesis of SUDEP.
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Affiliation(s)
- LeYuan Gu
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Qian Yu
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Yue Shen
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - YuLing Wang
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Qing Xu
- Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - HongHai Zhang
- Department of Anesthesiology, The Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou 310006, China; Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310006, China.
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20
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Feinstein JS, Gould D, Khalsa SS. Amygdala-driven apnea and the chemoreceptive origin of anxiety. Biol Psychol 2022; 170:108305. [PMID: 35271957 DOI: 10.1016/j.biopsycho.2022.108305] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 02/09/2022] [Accepted: 03/03/2022] [Indexed: 12/13/2022]
Abstract
Although the amygdala plays an important part in the pathogenesis of anxiety and generation of exteroceptive fear, recent discoveries have challenged the directionality of this brain-behavior relationship with respect to interoceptive fear. Here we highlight several paradoxical findings including: (1) amygdala lesion patients who experience excessive fear and panic following inhalation of carbon dioxide (CO2), (2) clinically anxious patients who have significantly smaller (rather than larger) amygdalae and a pronounced hypersensitivity toward CO2, and (3) epilepsy patients who exhibit apnea immediately following stimulation of their amygdala yet have no awareness that their breathing has stopped. The above findings elucidate an entirely novel role for the amygdala in the induction of apnea and inhibition of CO2-induced fear. Such a role is plausible given the strong inhibitory connections linking the central nucleus of the amygdala with respiratory and chemoreceptive centers in the brainstem. Based on this anatomical arrangement, we propose a model of Apnea-induced Anxiety (AiA) which predicts that recurring episodes of apnea are being unconsciously elicited by amygdala activation, resulting in transient spikes in CO2 that provoke fear and anxiety, and lead to characteristic patterns of escape and avoidance behavior in patients spanning the spectrum of anxiety. If this new conception of AiA proves to be true, and activation of the amygdala can repeatedly trigger states of apnea outside of one's awareness, then it remains possible that the chronicity of anxiety disorders is being interoceptively driven by a chemoreceptive system struggling to maintain homeostasis in the midst of these breathless states.
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Affiliation(s)
- Justin S Feinstein
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104; University of Iowa, Department of Neurology, Iowa City, Iowa, USA, 52242.
| | - Dylan Gould
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136
| | - Sahib S Khalsa
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104
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21
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Li Z, Wang Y, Li L, He H, Lin L, Pan M, Yang T, Liu Q. A bibliometric analysis of the cause of sudden unexplained death in forensic medicine: Research trends, hot spots and prospects. Comput Biol Med 2022; 144:105330. [DOI: 10.1016/j.compbiomed.2022.105330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 02/08/2022] [Accepted: 02/15/2022] [Indexed: 01/03/2023]
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22
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Martínez-Valdez L, Richardson V, Bautista-Márquez A, Hernández-Ávila M. Epidemiology of sudden infant death syndrome in Mexico, 2005-2020. Front Pediatr 2022; 10:1001089. [PMID: 36568434 PMCID: PMC9773828 DOI: 10.3389/fped.2022.1001089] [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: 07/22/2022] [Accepted: 11/11/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Sudden Infant Death Syndrome (SIDS) constitutes one of the main causes of mortality in children under one year of age in developed countries; it's frequency to varies geographically. In Mexico the real incidence of SIDS is not known. METHODS National databases of deaths in children under one year of age, from 2005 to 2020, were analyzed, due to Sudden Unexpected Infant Death (SUID) [SIDS (R95), accidental suffocation in a sleeping environment (W75), and other ill-defined and unspecified causes of mortality (R99), according to the International Classification of Diseases, tenth revision (ICD 10)]. Mortality rates per year of occurrence due to SUID and their subcategories were calculated. Simple frequencies of SIDS were obtained per year and month of occurrence, state of residence, age, place of death, and access to social security services. RESULTS In the study period 473,545 infant deaths occurred; 7,714 (1.62%) deaths were due to SUID; of these, 6,489 (84%) were due to SIDS, which is among the 10 leading causes of infant death in Mexico. The average mortality rate for SUID was 22.4/100,000 live births, for SIDS was 18.8/100,000 live births. Mortality rates within the states were variable, ranging from 2.4/100,000 to 105.1/100,000 live births. In 81% of SIDS records there was no autopsy; 38% of deaths due to SIDS occurred in infants under one month of age, up to 87% of deaths occurred in families without social security services or it was unknown, and 76.2% of deaths occurred at home. Deaths were more frequent during the last months of autumn and during winter. CONCLUSION In Mexico there is an underregistry of SIDS as cause of death, along with other SUID categories. Health workers need to be trained to improve diagnosis and data registration, including the practice of autopsies; additionally, it is necessary to implement a public health campaign.
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Affiliation(s)
- Libny Martínez-Valdez
- Dirección de Prestaciones Económicas y Sociales, El Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Vesta Richardson
- Dirección de Prestaciones Económicas y Sociales, El Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Aurora Bautista-Márquez
- Dirección de Prestaciones Económicas y Sociales, El Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Mauricio Hernández-Ávila
- Dirección de Prestaciones Económicas y Sociales, El Instituto Mexicano del Seguro Social, Mexico City, Mexico
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Neubauer J, Forst AL, Warth R, Both CP, Haas C, Thomas J. Genetic variants in eleven central and peripheral chemoreceptor genes in sudden infant death syndrome. Pediatr Res 2022; 92:1026-1033. [PMID: 35102300 PMCID: PMC9586864 DOI: 10.1038/s41390-021-01899-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 07/14/2021] [Accepted: 08/16/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Sudden infant death syndrome (SIDS) is still one of the leading causes of postnatal infant death in developed countries. The occurrence of SIDS is described by a multifactorial etiology that involves the respiratory control system including chemoreception. It is still unclear whether genetic variants in genes involved in respiratory chemoreception might play a role in SIDS. METHODS The exome data of 155 SIDS cases were screened for variants within 11 genes described in chemoreception. Pathogenicity of variants was assigned based on the assessment of variant types and in silico protein predictions according to the current recommendations of the American College of Medical Genetics and Genomics. RESULTS Potential pathogenic variants in genes encoding proteins involved in respiratory chemoreception could be identified in 5 (3%) SIDS cases. Two of the variants (R137S/A188S) were found in the KNCJ16 gene, which encodes for the potassium channel Kir5.1, presumably involved in central chemoreception. Electrophysiologic analysis of these KCNJ16 variants revealed a loss-of-function for the R137S variant but no obvious impairment for the A188S variant. CONCLUSIONS Genetic variants in genes involved in respiratory chemoreception may be a risk factor in a fraction of SIDS cases and may thereby contribute to the multifactorial etiology of SIDS. IMPACT What is the key message of your article? Gene variants encoding proteins involved in respiratory chemoreception may play a role in a minority of SIDS cases. What does it add to the existing literature? Although impaired respiratory chemoreception has been suggested as an important risk factor for SIDS, genetic variants in single genes seem to play a minor role. What is the impact? This study supports previous findings, which indicate that genetic variants in single genes involved in respiratory control do not have a dominant role in SIDS.
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Affiliation(s)
- Jacqueline Neubauer
- grid.7400.30000 0004 1937 0650Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Anna-Lena Forst
- grid.7727.50000 0001 2190 5763Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- grid.7727.50000 0001 2190 5763Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Christian Peter Both
- grid.412341.10000 0001 0726 4330Department of Anesthesiology, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Cordula Haas
- grid.7400.30000 0004 1937 0650Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Jörg Thomas
- Department of Anesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.
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24
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Whatley BP, Winston JS, Allen LA, Vos SB, Jha A, Scott CA, Smith AL, Chowdhury FA, Bomanji JB, Lhatoo SD, Harper RM, Diehl B. Distinct Patterns of Brain Metabolism in Patients at Risk of Sudden Unexpected Death in Epilepsy. Front Neurol 2021; 12:623358. [PMID: 34899550 PMCID: PMC8651549 DOI: 10.3389/fneur.2021.623358] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 10/25/2021] [Indexed: 12/21/2022] Open
Abstract
Objective: To characterize regional brain metabolic differences in patients at high risk of sudden unexpected death in epilepsy (SUDEP), using fluorine-18-fluorodeoxyglucose positron emission tomography (18FDG-PET). Methods: We studied patients with refractory focal epilepsy at high (n = 56) and low (n = 69) risk of SUDEP who underwent interictal 18FDG-PET as part of their pre-surgical evaluation. Binary SUDEP risk was ascertained by thresholding frequency of focal to bilateral tonic-clonic seizures (FBTCS). A whole brain analysis was employed to explore regional differences in interictal metabolic patterns. We contrasted these findings with regional brain metabolism more directly related to frequency of FBTCS. Results: Regions associated with cardiorespiratory and somatomotor regulation differed in interictal metabolism. In patients at relatively high risk of SUDEP, fluorodeoxyglucose (FDG) uptake was increased in the basal ganglia, ventral diencephalon, midbrain, pons, and deep cerebellar nuclei; uptake was decreased in the left planum temporale. These patterns were distinct from the effect of FBTCS frequency, where increasing frequency was associated with decreased uptake in bilateral medial superior frontal gyri, extending into the left dorsal anterior cingulate cortex. Significance: Regions critical to cardiorespiratory and somatomotor regulation and to recovery from vital challenges show altered interictal metabolic activity in patients with frequent FBTCS considered to be at relatively high-risk of SUDEP, and shed light on the processes that may predispose patients to SUDEP.
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Affiliation(s)
- Benjamin P Whatley
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom.,Division of Neurology, Dalhousie University, Halifax, NS, Canada
| | - Joel S Winston
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom.,Wellcome Trust Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Clinical Neurophysiology, King's College Hospital, London, United Kingdom
| | - Luke A Allen
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom.,Epilepsy Society MRI Unit, Chalfont St Peter, United Kingdom.,The Center for SUDEP Research, National Institutes of Neurological Disorders and Stroke, Bethesda, MD, United States
| | - Sjoerd B Vos
- Epilepsy Society MRI Unit, Chalfont St Peter, United Kingdom.,The Center for SUDEP Research, National Institutes of Neurological Disorders and Stroke, Bethesda, MD, United States.,Neuroradiological Academic Unit, Queen Square Institute of Neurology, University College London, London, United Kingdom.,Centre for Medical Image Computing, University College London, London, United Kingdom
| | - Ashwani Jha
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Catherine A Scott
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom.,The Center for SUDEP Research, National Institutes of Neurological Disorders and Stroke, Bethesda, MD, United States
| | - April-Louise Smith
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Fahmida A Chowdhury
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Jamshed B Bomanji
- Institute of Nuclear Medicine, University College London, London, United Kingdom
| | - Samden D Lhatoo
- The Center for SUDEP Research, National Institutes of Neurological Disorders and Stroke, Bethesda, MD, United States.,Epilepsy Center, Neurological Institute, University Hospitals Case Medical Center, Cleveland, OH, United States.,Department of Neurology, University of Texas Health Sciences Center at Houston, Houston, TX, United States
| | - Ronald M Harper
- The Center for SUDEP Research, National Institutes of Neurological Disorders and Stroke, Bethesda, MD, United States.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, United States
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom.,Epilepsy Society MRI Unit, Chalfont St Peter, United Kingdom.,The Center for SUDEP Research, National Institutes of Neurological Disorders and Stroke, Bethesda, MD, United States
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25
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Frassineti L, Lanatà A, Olmi B, Manfredi C. Multiscale Entropy Analysis of Heart Rate Variability in Neonatal Patients with and without Seizures. Bioengineering (Basel) 2021; 8:122. [PMID: 34562944 PMCID: PMC8469929 DOI: 10.3390/bioengineering8090122] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/03/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
The complex physiological dynamics of neonatal seizures make their detection challenging. A timely diagnosis and treatment, especially in intensive care units, are essential for a better prognosis and the mitigation of possible adverse effects on the newborn's neurodevelopment. In the literature, several electroencephalographic (EEG) studies have been proposed for a parametric characterization of seizures or their detection by artificial intelligence techniques. At the same time, other sources than EEG, such as electrocardiography, have been investigated to evaluate the possible impact of neonatal seizures on the cardio-regulatory system. Heart rate variability (HRV) analysis is attracting great interest as a valuable tool in newborns applications, especially where EEG technologies are not easily available. This study investigated whether multiscale HRV entropy indexes could detect abnormal heart rate dynamics in newborns with seizures, especially during ictal events. Furthermore, entropy measures were analyzed to discriminate between newborns with seizures and seizure-free ones. A cohort of 52 patients (33 with seizures) from the Helsinki University Hospital public dataset has been evaluated. Multiscale sample and fuzzy entropy showed significant differences between the two groups (p-value < 0.05, Bonferroni multiple-comparison post hoc correction). Moreover, interictal activity showed significant differences between seizure and seizure-free patients (Mann-Whitney Test: p-value < 0.05). Therefore, our findings suggest that HRV multiscale entropy analysis could be a valuable pre-screening tool for the timely detection of seizure events in newborns.
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Affiliation(s)
- Lorenzo Frassineti
- Department of Information Engineering, Università degli Studi di Firenze, Via Santa Marta 3, 50139 Firenze, Italy; (A.L.); (B.O.); (C.M.)
- Department of Medical Biotechnologies, Università di Siena, 53100 Siena, Italy
| | - Antonio Lanatà
- Department of Information Engineering, Università degli Studi di Firenze, Via Santa Marta 3, 50139 Firenze, Italy; (A.L.); (B.O.); (C.M.)
| | - Benedetta Olmi
- Department of Information Engineering, Università degli Studi di Firenze, Via Santa Marta 3, 50139 Firenze, Italy; (A.L.); (B.O.); (C.M.)
| | - Claudia Manfredi
- Department of Information Engineering, Università degli Studi di Firenze, Via Santa Marta 3, 50139 Firenze, Italy; (A.L.); (B.O.); (C.M.)
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26
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Abbott SBG, Souza GMPR. Chemoreceptor mechanisms regulating CO 2 -induced arousal from sleep. J Physiol 2021; 599:2559-2571. [PMID: 33759184 DOI: 10.1113/jp281305] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/16/2021] [Indexed: 12/24/2022] Open
Abstract
Arousal from sleep in response to CO2 is a life-preserving reflex that enhances ventilatory drive and facilitates behavioural adaptations to restore eupnoeic breathing. Recurrent activation of the CO2 -arousal reflex is associated with sleep disruption in obstructive sleep apnoea. In this review we examine the role of chemoreceptors in the carotid bodies, the retrotrapezoid nucleus and serotonergic neurons in the dorsal raphe in the CO2 -arousal reflex. We also provide an overview of the supra-medullary structures that mediate CO2 -induced arousal. We propose a framework for the CO2 -arousal reflex in which the activity of the chemoreceptors converges in the parabrachial nucleus to trigger cortical arousal.
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Affiliation(s)
- Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 29903, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 29903, USA
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27
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Johnson M, Samudra N, Gallagher MJ, Abou-Khalil B, Nobis WP. Near SUDEP during bilateral stereo-EEG monitoring characterized by diffuse postictal EEG suppression. Epilepsia 2021; 62:e60-e64. [PMID: 33617691 DOI: 10.1111/epi.16852] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 11/29/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the most common cause of death in patients with refractory epilepsy. The pathophysiology of SUDEP is unknown. Postictal phenomena such as postconvulsive immobility (PI), postictal generalized electroencephalography (EEG) suppression (PGES), arousal deficits, cardiac arrhythmias, central apneas, and obstructive apneas due to laryngospasms have been suggested to contribute to SUDEP. We present, to our knowledge, the first case of a near-SUDEP event in a patient undergoing intracranial, stereotactic EEG (sEEG) monitoring. This case spotlights potential mediators of SUDEP, most notably the striking PGES and postictal apnea. The nature of the sEEG investigation illustrates the extent of cortical and subcortical postictal EEG suppression and showcases a transient return of cerebral activity likely to be missed on scalp-EEG recording. Critically, this case emphasizes the importance of continuous cardiorespiratory monitoring and underscores the importance of postictal arousal as a pathophysiological mechanism in SUDEP.
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Affiliation(s)
- Michael Johnson
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Niyatee Samudra
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Martin J Gallagher
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bassel Abou-Khalil
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - William P Nobis
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
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28
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Gene variants associated with obstructive sleep apnea (OSA) in relation to sudden infant death syndrome (SIDS). Int J Legal Med 2021; 135:1499-1506. [PMID: 33559002 PMCID: PMC8206047 DOI: 10.1007/s00414-020-02480-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Background Both obstructive sleep apnea (OSA) and (at least a fraction of) sudden infant death syndrome (SIDS) are associated with impaired respiration. For OSA, an association with several gene variants was identified. Therefore, our hypothesis is that these polymorphisms might be of relevance in SIDS as well. Methods Twenty-four single nucleotide polymorphisms (SNPs) in 21 candidate genes connected to OSA, were genotyped in a total of 282 SIDS cases and 374 controls. Additionally, subgroups based on factors codetermining the SIDS risk (age, sex, season, and prone position) were established and compared as well. Results Two of the analyzed SNPs showed nominally significant differences between SIDS and control groups: rs1042714 in ADRB2 (adrenoceptor beta 2) and rs1800541 in EDN1 (endothelin 1). In the subgroup analyses, 10 further SNPs gave significant results. Nevertheless, these associations did not survive adjustment for multiple testing. Conclusions Our results suggest that there might be a link between SIDS and OSA and its resulting respiratory and cardiovascular problems, albeit this predisposition might be dependent on the combination with other, hitherto unknown gene variants. These findings may encourage replication studies to get a better understanding of this connection. Supplementary Information The online version contains supplementary material available at 10.1007/s00414-020-02480-0.
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29
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Petrucci AN, Joyal KG, Chou JW, Li R, Vencer KM, Buchanan GF. Post-ictal Generalized EEG Suppression is reduced by Enhancing Dorsal Raphe Serotonergic Neurotransmission. Neuroscience 2020; 453:206-221. [PMID: 33242541 DOI: 10.1016/j.neuroscience.2020.11.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 01/02/2023]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy. A proposed risk marker for SUDEP is the duration of post-ictal generalized EEG suppression (PGES). The mechanisms underlying PGES are unknown. Serotonin (5-HT) has been implicated in SUDEP pathophysiology. Seizures suppress activity of 5-HT neurons in the dorsal raphe nucleus (DRN). We hypothesized that suppression of DRN 5-HT neuron activity contributes to PGES and increasing 5-HT neurotransmission or stimulating the DRN before a seizure would decrease PGES duration. Adult C57BL/6J and Pet1-Cre mice received EEG/EMG electrodes, a bipolar stimulating/recording electrode in the right basolateral amygdala, and either a microdialysis guide cannula or an injection of adeno-associated virus (AAV) allowing expression of channelrhodopsin2 plus an optic fiber into the DRN. Systemic application of the selective 5-HT reuptake inhibitor citalopram (20 mg/kg) decreased PGES duration from seizures induced during wake (n = 23) and non-rapid eye movement (NREM) sleep (n = 13) whereas fluoxetine (10 mg/kg) pretreatment decreased PGES duration following seizures induced from wake (n = 11), but not NREM sleep (n = 9). Focal chemical (n = 6) or optogenetic (n = 8) stimulation of the DRN reduced PGES duration following seizures in kindled mice induced during wake. During PGES, animals exhibited immobility and suppression of EEG activity that was reduced by citalopram pretreatment. These results suggest 5-HT and the DRN may regulate PGES.
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Affiliation(s)
- Alexandra N Petrucci
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Department of Neurology, Carver College of Medicine, Carver College of Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States.
| | - Katelyn G Joyal
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Department of Neurology, Carver College of Medicine, Carver College of Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States.
| | - Jonathan W Chou
- Department of Neurology, Carver College of Medicine, Carver College of Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Department of Health and Human Physiology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA 52242, United States.
| | - Rui Li
- Department of Neurology, Carver College of Medicine, Carver College of Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States.
| | - Kimberly M Vencer
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Department of Health and Human Physiology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA 52242, United States
| | - Gordon F Buchanan
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Department of Neurology, Carver College of Medicine, Carver College of Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States.
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30
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Dibué M, Spoor JKH, Dremmen M, von Saß CF, Hänggi D, Steiger HJ, Ryvlin P, Kamp MA. Sudden death in epilepsy: There is room for intracranial pressure. Brain Behav 2020; 10:e01838. [PMID: 32949224 PMCID: PMC7667321 DOI: 10.1002/brb3.1838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/18/2020] [Accepted: 08/26/2020] [Indexed: 01/25/2023] Open
Abstract
INTRODUCTION Sudden unexpected death in patients with epilepsy (SUDEP) remains a poorly understood entity, and it is unclear whether the same pathomechanisms underlie all sudden deaths occurring in patients with epilepsy. One aspect not included in current models of SUDEP is the role of increased intracranial pressure (ICP) which can be observed immediately upon seizure activity in neurosurgical practice. METHODS We conducted a systematic review of the occurrence of edema in patients with epilepsy reported to have died of sudden death who underwent brain autopsy or postmortem brain imaging and discuss how increased ICP may contribute to clinical features of SUDEP. RESULTS 19 eligible studies comprising a total of 623 patients were identified. Edema-mostly mild or moderate-was reported in 17% of cases and 74% of studies. 1% (n = 6) of the overall cases were clearly identified as having Dravet syndrome or an SCN1A mutation. In these patients, edema was found in 4 (67%) of cases. CONCLUSION Edema is regularly found in patients with epilepsy classified to have died from SUDEP. We argue that seizures preceding SUDEP may in certain cases elicit acute edema which may represent an additional contributing factor in the cascade of events leading to sudden death of patients with epilepsy. Furthermore, we hypothesize that mild edema may especially progress to severe edema in patients with sodium channel mutations which may represent an important mechanism to investigate in the context of understanding the significantly elevated risk of SUDEP in patients with SCN1A mutations.
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Affiliation(s)
- Maxine Dibué
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Jochem K H Spoor
- Department of Neurosurgery, Erasmus MC University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Marjolein Dremmen
- Department of Radiology, Erasmus MC University Medical Center Rotterdam, Rotterdam, The Netherlands
| | | | - Daniel Hänggi
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Hans-Jakob Steiger
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Philippe Ryvlin
- Department of Clinical Neurosciences, Centre Hospitalo-Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Marcel A Kamp
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
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Cardiorespiratory Dysfunction Induced by Brainstem Spreading Depolarization: A Potential Mechanism for SUDEP. J Neurosci 2020; 40:2387-2389. [PMID: 32188743 DOI: 10.1523/jneurosci.3053-19.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/09/2020] [Accepted: 02/17/2020] [Indexed: 11/21/2022] Open
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Stewart M, Silverman JB, Sundaram K, Kollmar R. Causes and Effects Contributing to Sudden Death in Epilepsy and the Rationale for Prevention and Intervention. Front Neurol 2020; 11:765. [PMID: 32849221 PMCID: PMC7411179 DOI: 10.3389/fneur.2020.00765] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/22/2020] [Indexed: 12/15/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) claims the lives of one in every thousand epileptic patients each year. Autonomic, cardiac, and respiratory pieces to a mechanistic puzzle have not yet been completely assembled. We propose a single sequence of causes and effects that unifies disparate and competitive concepts into a single algorithm centered on ictal obstructive apnea. Based on detailed animal studies that are sometimes impossible in humans, and striking parallels with a growing body of clinical examples, this framework (1) accounts for the autonomic, cardiac, and respiratory data to date by showing the causal relationships between specific elements, and (2) highlights specific kinds of data that can be used to precisely classify various patient outcomes. The framework also justifies a “near miss” designation to be applied to any cases with evidence of obstructive apnea even, and perhaps especially, in individuals that do not require resuscitation. Lastly, the rationale for preventative oxygen therapy is demonstrated. With better mechanistic understanding of SUDEP, we suggest changes for detection and classification to increase survival rates and improve risk stratification.
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Affiliation(s)
- Mark Stewart
- Department of Neurology, State University of New York Health Sciences University, Brooklyn, NY, United States.,Department of Physiology & Pharmacology, State University of New York Health Sciences University, Brooklyn, NY, United States
| | - Joshua B Silverman
- Department of Otolaryngology, North Shore Long Island Jewish Medical Center, New Hyde Park, NY, United States
| | - Krishnamurthi Sundaram
- Department of Otolaryngology, State University of New York Health Sciences University, Brooklyn, NY, United States
| | - Richard Kollmar
- Department of Otolaryngology, State University of New York Health Sciences University, Brooklyn, NY, United States.,Department of Cell Biology, State University of New York Health Sciences University, Brooklyn, NY, United States
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Gauda EB, Conde S, Bassi M, Zoccal DB, Almeida Colombari DS, Colombari E, Despotovic N. Leptin: Master Regulator of Biological Functions that Affects Breathing. Compr Physiol 2020; 10:1047-1083. [PMID: 32941688 DOI: 10.1002/cphy.c190031] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity is a global epidemic in developed countries accounting for many of the metabolic and cardiorespiratory morbidities that occur in adults. These morbidities include type 2 diabetes, sleep-disordered breathing (SDB), obstructive sleep apnea, chronic intermittent hypoxia, and hypertension. Leptin, produced by adipocytes, is a master regulator of metabolism and of many other biological functions including central and peripheral circuits that control breathing. By binding to receptors on cells and neurons in the brainstem, hypothalamus, and carotid body, leptin links energy and metabolism to breathing. In this comprehensive article, we review the central and peripheral locations of leptin's actions that affect cardiorespiratory responses during health and disease, with a particular focus on obesity, SDB, and its effects during early development. Obesity-induced hyperleptinemia is associated with centrally mediated hypoventilation with decrease CO2 sensitivity. On the other hand, hyperleptinemia augments peripheral chemoreflexes to hypoxia and induces sympathoexcitation. Thus, "leptin resistance" in obesity is relative. We delineate the circuits responsible for these divergent effects, including signaling pathways. We review the unique effects of leptin during development on organogenesis, feeding behavior, and cardiorespiratory responses, and how undernutrition and overnutrition during critical periods of development can lead to cardiorespiratory comorbidities in adulthood. We conclude with suggestions for future directions to improve our understanding of leptin dysregulation and associated clinical diseases and possible therapeutic targets. Lastly, we briefly discuss the yin and the yang, specifically the contribution of relative adiponectin deficiency in adults with hyperleptinemia to the development of metabolic and cardiovascular disease. © 2020 American Physiological Society. Compr Physiol 10:1047-1083, 2020.
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Affiliation(s)
- Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Silvia Conde
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Lisboa, Portugal
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Debora Simoes Almeida Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Nikola Despotovic
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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35
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Purnell BS, Buchanan GF. Free-running circadian breathing rhythms are eliminated by suprachiasmatic nucleus lesion. J Appl Physiol (1985) 2020; 129:49-57. [PMID: 32501775 PMCID: PMC7469233 DOI: 10.1152/japplphysiol.00211.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/06/2020] [Accepted: 06/02/2020] [Indexed: 11/22/2022] Open
Abstract
It is widely agreed that breathing is subject to circadian regulation. Circadian differences in respiratory physiology significantly impact a number of diseases including sleep apnea, asthma, and seizure-induced death. The effect of time of day on breathing has been previously characterized; however, an endogenous free-running respiratory rhythm in mammals has not previously been described. Furthermore, it is assumed that circadian rhythms in breathing are dependent on the hypothalamic suprachiasmatic nucleus (SCN), the home of the mammalian central circadian oscillator, but this has not been shown experimentally. The breathing of mice was monitored during wakefulness using whole body plethysmography at six times of day while housed under light-dark conditions and at six circadian phases while housed under constant darkness. Respiratory frequency and minute ventilation, but not tidal volume, were significantly higher during the active phase in both entrained and free-running conditions. To determine whether circadian regulation of breathing requires the SCN, in separate sets of animals this structure was electrolytically lesioned bilaterally or a sham surgery was performed, and breathing was measured at six different time points. Time-dependent oscillations in breathing were lost in SCN-lesioned animals, but not those subjected to sham surgery. These results suggest that breathing is subject to circadian regulation via the SCN. Mechanistic insights into the circadian regulation of breathing may lead to targeted interventions to reduce the morbidity and mortality associated with diseases with respiratory pathophysiology.NEW & NOTEWORTHY It has long been appreciated that breathing is altered by time of day. This study demonstrates that rhythmicity in breathing persists in constant darkness but is dependent on the suprachiasmatic nucleus in the hypothalamus. Understanding circadian rhythms in breathing may be important for the treatment and prevention of diseases such as sleep apnea and sudden unexpected death in epilepsy.
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Affiliation(s)
- Benton S Purnell
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Gordon F Buchanan
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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36
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Kelly MN, Smith DN, Sunshine MD, Ross A, Zhang X, Gumz ML, Esser KA, Mitchell GS. Circadian clock genes and respiratory neuroplasticity genes oscillate in the phrenic motor system. Am J Physiol Regul Integr Comp Physiol 2020; 318:R1058-R1067. [PMID: 32348679 DOI: 10.1152/ajpregu.00010.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Circadian rhythms are endogenous and entrainable daily patterns of physiology and behavior. Molecular mechanisms underlie circadian rhythms, characterized by an ~24-h pattern of gene expression of core clock genes. Although it has long been known that breathing exhibits circadian rhythms, little is known concerning clock gene expression in any element of the neuromuscular system controlling breathing. Furthermore, we know little concerning gene expression necessary for specific respiratory functions, such as phrenic motor plasticity. Thus, we tested the hypotheses that transcripts for clock genes (Bmal1, Clock, Per1, and Per2) and molecules necessary for phrenic motor plasticity (Htr2a, Htr2b, Bdnf, and Ntrk2) oscillate in regions critical for phrenic/diaphragm motor function via RT-PCR. Tissues were collected from male Sprague-Dawley rats entrained to a 12-h light-dark cycle at 4 zeitgeber times (ZT; n = 8 rats/group): ZT5, ZT11, ZT17, and ZT23; ZT0 = lights on. Here, we demonstrate that 1) circadian clock genes (Bmal1, Clock, Per1, and Per2) oscillate in regions critical for phrenic/diaphragm function, including the caudal medulla, ventral C3-C5 cervical spinal cord, and diaphragm; 2) the clock protein BMAL1 is localized within CtB-labeled phrenic motor neurons; 3) genes necessary for intermittent hypoxia-induced phrenic/diaphragm motor plasticity (Htr2b and Bdnf) oscillate in the caudal medulla and ventral C3-C5 spinal cord; and 4) there is higher intensity of immunofluorescent BDNF protein within phrenic motor neurons at ZT23 compared with ZT11 (n = 11 rats/group). These results suggest local circadian clocks exist in the phrenic motor system and confirm the potential for local circadian regulation of neuroplasticity and other elements of the neural network controlling breathing.
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Affiliation(s)
- Mia N Kelly
- Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, Florida.,Department of Physical Therapy, University of Florida, Gainesville, Florida.,McKnight Brain Institute, University of Florida, Gainesville, Florida
| | - Danelle N Smith
- Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, Florida
| | - Michael D Sunshine
- Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, Florida.,Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Ashley Ross
- Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, Florida.,Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Xiping Zhang
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Michelle L Gumz
- Department of Medicine, University of Florida, Gainesville, Florida
| | - Karyn A Esser
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Gordon S Mitchell
- Center for Respiratory Research and Rehabilitation, University of Florida, Gainesville, Florida.,Department of Physical Therapy, University of Florida, Gainesville, Florida.,McKnight Brain Institute, University of Florida, Gainesville, Florida
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37
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Pensel MC, Nass RD, Taubøll E, Aurlien D, Surges R. Prevention of sudden unexpected death in epilepsy: current status and future perspectives. Expert Rev Neurother 2020; 20:497-508. [PMID: 32270723 DOI: 10.1080/14737175.2020.1754195] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Introduction: Sudden unexpected death in epilepsy (SUDEP) affects about 1 in 1000 people with epilepsy, and even more in medically refractory epilepsy. As most people are between 20 and 40 years when dying suddenly, SUDEP leads to a considerable loss of potential life years. The most important risk factors are nocturnal and tonic-clonic seizures, underscoring that supervision and effective seizure control are key elements for SUDEP prevention. The question of whether specific antiepileptic drugs are linked to SUDEP is still controversially discussed. Knowledge and education about SUDEP among health-care professionals, patients, and relatives are of outstanding importance for preventive measures to be taken, but still poor and widely neglected.Areas covered: This article reviews epidemiology, pathophysiology, risk factors, assessment of individual SUDEP risk and available measures for SUDEP prevention. Literature search was done using Medline and Pubmed in October 2019.Expert opinion: Significant advances in the understanding of SUDEP were made in the last decade which allow testing of novel strategies to prevent SUDEP. Promising current strategies target neuronal mechanisms of brain stem dysfunction, cardiac susceptibility for fatal arrhythmias, and reliable detection of tonic-clonic seizures using mobile health technologies.Abbreviations: AED, antiepileptic drug; CBZ, carbamazepine; cLQTS, congenital long QT syndrome; EMU, epilepsy monitoring unit; FBTCS, focal to bilateral tonic-clonic seizures; GTCS, generalized tonic-clonic seizures; ICA, ictal central apnea; LTG, lamotrigine; PCCA, postconvulsive central apnea; PGES, postictal generalized EEG suppression; SRI, serotonin reuptake inhibitor; SUDEP, sudden unexpected death in epilepsy; TCS, tonic-clonic seizures.
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Affiliation(s)
| | | | - Erik Taubøll
- Department of Neurology, Oslo University Hospital, Nydalen, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Dag Aurlien
- Neuroscience Research Group and Department of Neurology, Stavanger University Hospital, Stavanger, Norway
| | - Rainer Surges
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
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Rhone AE, Kovach CK, Harmata GI, Sullivan AW, Tranel D, Ciliberto MA, Howard MA, Richerson GB, Steinschneider M, Wemmie JA, Dlouhy BJ. A human amygdala site that inhibits respiration and elicits apnea in pediatric epilepsy. JCI Insight 2020; 5:134852. [PMID: 32163374 PMCID: PMC7213805 DOI: 10.1172/jci.insight.134852] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/26/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUNDSeizure-induced inhibition of respiration plays a critical role in sudden unexpected death in epilepsy (SUDEP). However, the mechanisms underlying seizure-induced central apnea in pediatric epilepsy are unknown.METHODSWe studied 8 pediatric patients with intractable epilepsy undergoing intracranial electroencephalography. We recorded respiration during seizures and during electrical stimulation mapping of 174 forebrain sites. A machine-learning algorithm was used to delineate brain regions that inhibit respiration.RESULTSIn 2 patients, apnea coincided with seizure spread to the amygdala. Supporting a role for the amygdala in breathing inhibition in children, electrically stimulating the amygdala produced apnea in all 8 subjects (3-17 years old). These effects did not depend on epilepsy type and were relatively specific to the amygdala, as no other site affected breathing. Remarkably, patients were unaware that they had stopped breathing, and none reported dyspnea or arousal, findings critical for SUDEP. Finally, a machine-learning algorithm based on 45 stimulation sites and 210 stimulation trials identified a focal subregion in the human amygdala that consistently produced apnea. This site, which we refer to as the amygdala inhibition of respiration (AIR) site includes the medial subregion of the basal nuclei, cortical and medial nuclei, amygdala transition areas, and intercalated neurons.CONCLUSIONSA focal site in the amygdala inhibits respiration and induces apnea (AIR site) when electrically stimulated and during seizures in children with epilepsy. This site may prove valuable for determining those at greatest risk for SUDEP and as a therapeutic target.FUNDINGNational Institute of Neurological Disorders and Stroke - Congress of Neurological Surgeons, National Institute of General Medical Sciences, Roy J. Carver Charitable Trust.
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Affiliation(s)
| | | | - Gail I.S. Harmata
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Pharmacological Sciences Training Program
- Department of Psychiatry
| | | | - Daniel Tranel
- Iowa Neuroscience Institute
- Department of Psychological and Brain Sciences
- Department of Neurology
| | | | - Matthew A. Howard
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
| | - George B. Richerson
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Department of Neurology
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - John A. Wemmie
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Department of Psychiatry
- Department of Neurology
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Brian J. Dlouhy
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
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39
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Petrucci AN, Joyal KG, Purnell BS, Buchanan GF. Serotonin and sudden unexpected death in epilepsy. Exp Neurol 2020; 325:113145. [PMID: 31866464 PMCID: PMC7029792 DOI: 10.1016/j.expneurol.2019.113145] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/12/2019] [Accepted: 12/10/2019] [Indexed: 12/20/2022]
Abstract
Epilepsy is a highly prevalent disease characterized by recurrent, spontaneous seizures. Approximately one-third of epilepsy patients will not achieve seizure freedom with medical management and become refractory to conventional treatments. These patients are at greatest risk for sudden unexpected death in epilepsy (SUDEP). The exact etiology of SUDEP is unknown, but a combination of respiratory, cardiac, neuronal electrographic dysfunction, and arousal impairment is thought to underlie SUDEP. Serotonin (5-HT) is involved in regulation of breathing, sleep/wake states, arousal, and seizure modulation and has been implicated in the pathophysiology of SUDEP. This review explores the current state of understanding of the relationship between 5-HT, epilepsy, and respiratory and autonomic control processes relevant to SUDEP in epilepsy patients and in animal models.
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Affiliation(s)
- Alexandra N Petrucci
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States of America; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States of America
| | - Katelyn G Joyal
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States of America; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States of America
| | - Benton S Purnell
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States of America; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States of America
| | - Gordon F Buchanan
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States of America; Department of Neurology, University of Iowa, Iowa City, IA 52242, United States of America; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States of America.
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40
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Jones JE, Asato MR, Brown MG, Doss JL, Felton EA, Kearney JA, Talos D, Dacks PA, Whittemore V, Poduri A. Epilepsy Benchmarks Area IV: Limit or Prevent Adverse Consequence of Seizures and Their Treatment Across the Life Span. Epilepsy Curr 2020; 20:31S-39S. [PMID: 31973592 PMCID: PMC7031803 DOI: 10.1177/1535759719895277] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Epilepsy represents a complex spectrum disorder, with patients sharing seizures as a common symptom and manifesting a broad array of additional clinical phenotypes. To understand this disorder and treat individuals who live with epilepsy, it is important not only to identify pathogenic mechanisms underlying epilepsy but also to understand their relationships with other health-related factors. Benchmarks Area IV focuses on the impact of seizures and their treatment on quality of life, development, cognitive function, and other aspects and comorbidities that often affect individuals with epilepsy. Included in this review is a discussion on sudden unexpected death in epilepsy and other causes of mortality, a major area of research focus with still many unanswered questions. We also draw attention to special populations, such as individuals with nonepileptic seizures and pregnant women and their offspring. In this study, we review the progress made in these areas since the 2016 review of the Benchmarks Area IV and discuss challenges and opportunities for future study.
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Affiliation(s)
- Jana E Jones
- University of Wisconsin School of Medicine & Public Health, Madison, WI, USA
| | - Miya R Asato
- Division of Child Neurology, UPMC Children's Hospital of Pittsburgh, PA, USA
| | - Mesha-Gay Brown
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | | | - Elizabeth A Felton
- University of Wisconsin School of Medicine & Public Health, Madison, WI, USA
| | | | - Delia Talos
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Vicky Whittemore
- Division of Neuroscience, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MA, USA.,Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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41
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Souza GMPR, Stornetta RL, Stornetta DS, Abbott SBG, Guyenet PG. Contribution of the Retrotrapezoid Nucleus and Carotid Bodies to Hypercapnia- and Hypoxia-induced Arousal from Sleep. J Neurosci 2019; 39:9725-9737. [PMID: 31641048 PMCID: PMC6891059 DOI: 10.1523/jneurosci.1268-19.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/03/2019] [Accepted: 10/16/2019] [Indexed: 11/21/2022] Open
Abstract
The combination of hypoxia and hypercapnia during sleep produces arousal, which helps restore breathing and normalizes blood gases. Hypercapnia and hypoxia produce arousal in mammals by activating central (pH-sensitive) and peripheral (primarily O2-sensitive) chemoreceptors. The relevant chemoreceptors and the neuronal circuits responsible for arousal are largely unknown. Here we examined the contribution of two lower brainstem nuclei that could be implicated in CO2 and hypoxia-induced arousal: the retrotrapezoid nucleus (RTN), a CO2-responsive nucleus, which mediates the central respiratory chemoreflex; and the C1 neurons, which are hypoxia activated and produce arousal and blood pressure increases when directly stimulated. Additionally, we assessed the contribution of the carotid bodies (CBs), the main peripheral chemoreceptors in mammals, to hypoxia and CO2-induced arousal. In unanesthetized male rats, we tested whether ablation of the RTN, CBs, or C1 neurons affects arousal from sleep and respiratory responses to hypercapnia or hypoxia. The sleep-wake pattern was monitored by EEG and neck EMG recordings and breathing by whole-body plethysmography. The latency to arousal in response to hypoxia or hypercapnia was determined along with changes in ventilation coincident with the arousal. RTN lesions impaired CO2-induced arousal but had no effect on hypoxia-induced arousal. CB ablation impaired arousal to hypoxia and, to a lesser extent, hypercapnia. C1 neuron ablation had no effect on arousal. Thus, the RTN contributes to CO2-induced arousal, whereas the CBs contribute to both hypoxia and CO2-induced arousal. Asphyxia-induced arousal likely requires the combined activation of RTN, CBs and other central chemoreceptors.SIGNIFICANCE STATEMENT Hypercapnia and hypoxia during sleep elicit arousal, which facilitates airway clearing in the case of obstruction and reinstates normal breathing in the case of hypoventilation or apnea. Arousal can also be detrimental to health by interrupting sleep. We sought to clarify how CO2 and hypoxia cause arousal. We show that the retrotrapezoid nucleus, a brainstem nucleus that mediates the effect of brain acidification on breathing, also contributes to arousal elicited by CO2 but not hypoxia. We also show that the carotid bodies contribute predominantly to hypoxia-induced arousal. Lesions of the retrotrapezoid nucleus or carotid bodies attenuate, but do not eliminate, arousal to CO2 or hypoxia; therefore, we conclude that these structures are not the sole trigger of CO2 or hypoxia-induced arousal.
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Affiliation(s)
- George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Daniel S Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
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42
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Gauda EB, McLemore GL. Premature birth, homeostatic plasticity and respiratory consequences of inflammation. Respir Physiol Neurobiol 2019; 274:103337. [PMID: 31733340 DOI: 10.1016/j.resp.2019.103337] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/11/2019] [Accepted: 11/10/2019] [Indexed: 12/23/2022]
Abstract
Infants who are born premature can have persistent apnea beyond term gestation, reemergence of apnea associated with inflammation during infancy, increased risk of sudden unexplained death, and sleep disorder breathing during infancy and childhood. The autonomic nervous system, particularly the central neural networks that control breathing and peripheral and central chemoreceptors and mechanoreceptors that modulate the activity of the central respiratory network, are rapidly developing during the last trimester (22-37 weeks gestation) of fetal life. With advances in neonatology, in well-resourced, developed countries, infants born as young as 23 weeks gestation can survive. Thus, a substantial part of maturation of central and peripheral systems that control breathing occurs ex-utero in infants born at the limit of viability. The balance of excitatory and inhibitory influences dictates the ultimate output from the central respiratory network. We propose in this review that simply being born early in the last trimester can trigger homeostatic plasticity within the respiratory network tipping the balance toward inhibition that persists in infancy. We discuss the intersection of premature birth, homeostatic plasticity and biological mechanisms leading to respiratory depression during inflammation in former premature infants.
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Affiliation(s)
- Estelle B Gauda
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics, University of Toronto, Toronto, Ontario, M5G 1X8, Canada.
| | - Gabrielle L McLemore
- Department of Biology, School of Computer, Mathematics and Natural Sciences (SCMNS), Morgan State University, Baltimore, MD, 21251, United States
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43
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Li R, Buchanan GF. Scurrying to Understand Sudden Expected Death in Epilepsy: Insights From Animal Models. Epilepsy Curr 2019; 19:390-396. [PMID: 31526023 PMCID: PMC6891182 DOI: 10.1177/1535759719874787] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy, accounting for up to 17% of deaths in patients with epilepsy. The pathophysiology of SUDEP has remained unclear, largely because it is unpredictable and commonly unwitnessed. This poses a great challenge to studies in patients. Recently, there has been an increase in animal studies to try to better understand the pathophysiology of SUDEP. In this current review, we focus on developments through seizure-induced death models and the preventative strategies they may reveal.
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Affiliation(s)
- Rui Li
- Department of Neurology, Carver College of Medicine, University of Iowa, IA, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, IA, USA
| | - Gordon F. Buchanan
- Department of Neurology, Carver College of Medicine, University of Iowa, IA, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, IA, USA
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44
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Patodia S, Paradiso B, Ellis M, Somani A, Sisodiya SM, Devinsky O, Thom M. Characterisation of medullary astrocytic populations in respiratory nuclei and alterations in sudden unexpected death in epilepsy. Epilepsy Res 2019; 157:106213. [PMID: 31610338 DOI: 10.1016/j.eplepsyres.2019.106213] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/20/2019] [Accepted: 09/30/2019] [Indexed: 12/29/2022]
Abstract
Central failure of respiration during a seizure is one possible mechanism for sudden unexpected death in epilepsy (SUDEP). Neuroimaging studies indicate volume loss in the medulla in SUDEP and a post mortem study has shown reduction in neuromodulatory neuropeptidergic and monoaminergic neurones in medullary respiratory nuclear groups. Specialised glial cells identified in the medulla are considered essential for normal respiratory regulation including astrocytes with pacemaker properties in the pre-Botzinger complex and populations of subpial and perivascular astrocytes, sensitive to increased pCO2, that excite respiratory neurones. Our aim was to explore niches of medullary astrocytes in SUDEP cases compared to controls. In 48 brainstems from three groups, SUDEP (20), epilepsy controls (10) and non-epilepsy controls (18), sections through the medulla were labelled for GFAP, vimentin and functional markers, astrocytic gap junction protein connexin43 (Cx43) and adenosine A1 receptor (A1R). Regions including the ventro-lateral medulla (VLM; for the pre-Bötzinger complex), Median Raphe (MR) and lateral medullary subpial layer (MSPL) were quantified using image analysis for glial cell populations and compared between groups. Findings included morphologically and regionally distinct vimentin/Cx34-positive glial cells in the VLM and MR in close proximity to neurones. We noted a reduction of vimentin-positive glia in the VLM and MSPL and Cx43 glia in the MR in SUDEP cases compared to control groups (p < 0.05-0.005). In addition, we identified vimentin, Cx43 and A1R positive glial cells in the MSPL region which likely correspond to chemosensory glia identified experimentally. In conclusion, altered medullary glial cell populations could contribute to impaired respiratory regulatory capacity and vulnerability to SUDEP and warrant further investigation.
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Affiliation(s)
- Smriti Patodia
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Beatrice Paradiso
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom; Cardiovascular Pathology Unit, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua Medical School, Padua, Italy
| | - Matthew Ellis
- Departments of Neuropathology, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Alyma Somani
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Sanjay M Sisodiya
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom
| | - Orrin Devinsky
- New York University School of Medicine, Comprehensive Epilepsy Center, New York, United States
| | - Maria Thom
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom; Departments of Neuropathology, UCL Queen Square Institute of Neurology, London, WC1N 3BG, United Kingdom.
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45
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Sex differences in breathing. Comp Biochem Physiol A Mol Integr Physiol 2019; 238:110543. [PMID: 31445081 DOI: 10.1016/j.cbpa.2019.110543] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 01/15/2023]
Abstract
Breathing is a vital behavior that ensures both the adequate supply of oxygen and the elimination of CO2, and it is influenced by many factors. Despite that most of the studies in respiratory physiology rely heavily on male subjects, there is much evidence to suggest that sex is an important factor in the respiratory control system, including the susceptibility for some diseases. These different respiratory responses in males and females may be related to the actions of sex hormones, especially in adulthood. These hormones affect neuromodulatory systems that influence the central medullary rhythm/pontine pattern generator and integrator, sensory inputs to the integrator and motor output to the respiratory muscles. In this article, we will first review the sex dependence on the prevalence of some respiratory-related diseases. Then, we will discuss the role of sex and gonadal hormones in respiratory control under resting conditions and during respiratory challenges, such as hypoxia and hypercapnia, and whether hormonal fluctuations during the estrous/menstrual cycle affect breathing control. We will then discuss the role of the locus coeruleus, a sexually dimorphic CO2/pH-chemosensitive nucleus, on breathing regulation in males and females. Next, we will highlight the studies that exist regarding sex differences in respiratory control during development. Finally, the few existing studies regarding the influence of sex on breathing control in non-mammalian vertebrates will be discussed.
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46
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Hatini PG, Commons KG. Serotonin abnormalities in Dravet syndrome mice before and after the age of seizure onset. Brain Res 2019; 1724:146399. [PMID: 31445030 DOI: 10.1016/j.brainres.2019.146399] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/12/2019] [Accepted: 08/20/2019] [Indexed: 01/19/2023]
Abstract
Dravet syndrome (DS) is a genetic form of severe epilepsy often associated with mutation of the SCN1A gene encoding the voltage gated sodium channel Nav1.1. Typically refractive to conventional therapy, serotonin neurotransmission may be an innovative target for treatment. To further understand the role of serotonin in this disorder, in this study we examined the state of the endogenous serotonin system in an Scn1a+/- mouse model of DS. Examined at an age before seizures appear, we found the hypothermic effect of 5-HT1A receptor agonist administration was attenuated. HPLC analysis of brain monoamine content revealed modestly reduced serotonin levels in tissue samples of the midbrain that included the dorsal raphe nucleus but no changes elsewhere in the brain. The reduced sensitivity to 5-HT1A agonist administration seen at young ages reversed after the age of seizure development when mice showed an exaggerated hypothermic response. Likewise, adult DS mice showed a pronounced hypersensitivity to a 5-HT2A/2C agonist. As adults however monoamine levels were not detectably altered. Thus there are alterations in the endogenous serotonin system that both precede and follow the appearance of seizure in DS mice, most strikingly in the response to agonist administration.
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Affiliation(s)
- Paul G Hatini
- Department of Anesthesiology, Perioperative and Pain Medicine, Children's Hospital, Boston, Department of Anæsthesia, Harvard Medical School, United States
| | - Kathryn G Commons
- Department of Anesthesiology, Perioperative and Pain Medicine, Children's Hospital, Boston, Department of Anæsthesia, Harvard Medical School, United States.
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