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Iyer SH, Hinman JE, Warren T, Matthews SA, Simeone TA, Simeone KA. Altered ventilatory responses to hypercapnia-hypoxia challenges in a preclinical SUDEP model involve orexin neurons. Neurobiol Dis 2024; 199:106592. [PMID: 38971479 DOI: 10.1016/j.nbd.2024.106592] [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] [Received: 12/22/2023] [Revised: 06/25/2024] [Accepted: 07/02/2024] [Indexed: 07/08/2024] Open
Abstract
Failure to recover from repeated hypercapnia and hypoxemia (HH) challenges caused by severe GCS and postictal apneas may contribute to sudden unexpected death in epilepsy (SUDEP). Our previous studies found orexinergic dysfunction contributes to respiratory abnormalities in a preclinical model of SUDEP, Kcna1-/- mice. Here, we developed two gas challenges consisting of repeated HH exposures and used whole body plethysmography to determine whether Kcna1-/- mice have detrimental ventilatory responses. Kcna1-/- mice exhibited an elevated ventilatory response to a mild repeated hypercapnia-hypoxia (HH) challenge compared to WT. Moreover, 71% of Kcna1-/- mice failed to survive a severe repeated HH challenge, whereas all WT mice recovered. We next determined whether orexin was involved in these differences. Pretreating Kcna1-/- mice with a dual orexin receptor antagonist rescued the ventilatory response during the mild challenge and all subjects survived the severe challenge. In ex vivo extracellular recordings in the lateral hypothalamus of coronal brain slices, we found reducing pH either inhibits or stimulates putative orexin neurons similar to other chemosensitive neurons; however, a significantly greater percentage of putative orexin neurons from Kcna1-/-mice were stimulated and the magnitude of stimulation was increased resulting in augmentation of the calculated chemosensitivity index relative to WT. Collectively, our data suggest that increased chemosensitive activity of orexin neurons may be pathologic in the Kcna1-/- mouse model of SUDEP, and contribute to elevated ventilatory responses. Our preclinical data suggest that those at high risk for SUDEP may be more sensitive to HH challenges, whether induced by seizures or other means; and the depth and length of the HH exposure could dictate the probability of survival.
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Affiliation(s)
- Shruthi H Iyer
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Jillian E Hinman
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Ted Warren
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Stephanie A Matthews
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Timothy A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA.
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Nobili L, Cordani R, Arnaldi D, Mattioli P, Veneruso M, Ng M. Rapid eye movement sleep and epilepsy: exploring interactions and therapeutic prospects. J Sleep Res 2024:e14251. [PMID: 38842061 DOI: 10.1111/jsr.14251] [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: 02/11/2024] [Revised: 03/21/2024] [Accepted: 05/07/2024] [Indexed: 06/07/2024]
Abstract
While research interest in the relationship between sleep and epilepsy is growing, it primarily centres on the effects of non-rapid eye movement (NREM) sleep in favouring seizures. Nonetheless, a noteworthy aspect is the observation that, in the lives of patients with epilepsy, REM sleep represents the moment with the least epileptic activity and the lowest probability of having a seizure. Studies demonstrate a suppressive effect of phasic REM sleep on interictal epileptiform discharges, potentially offering insights into epilepsy localisation and management. Furthermore, epilepsy impacts REM sleep, with successful treatment correlating with improved REM sleep quality. Novel therapeutic strategies aim to harness REM's anti-epileptic effects, including pharmacological approaches targeting orexinergic systems and neuromodulation techniques promoting cortical desynchronisation. These findings underscore the intricate relationship between REM sleep and epilepsy, highlighting avenues for further research and therapeutic innovation in epilepsy management.
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Affiliation(s)
- Lino Nobili
- Child Neuropsychiatry Unit, IRCCS Istituto Giannina Gaslini, Member of the European Reference Network EpiCARE, Genoa, Italy
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Child and Maternal Health (DINOGMI), University of Genoa, Genoa, Italy
| | - Ramona Cordani
- Child Neuropsychiatry Unit, IRCCS Istituto Giannina Gaslini, Member of the European Reference Network EpiCARE, Genoa, Italy
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Child and Maternal Health (DINOGMI), University of Genoa, Genoa, Italy
| | - Dario Arnaldi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Child and Maternal Health (DINOGMI), University of Genoa, Genoa, Italy
- Neurophysiopathology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Pietro Mattioli
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Child and Maternal Health (DINOGMI), University of Genoa, Genoa, Italy
- Neurophysiopathology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Marco Veneruso
- Child Neuropsychiatry Unit, IRCCS Istituto Giannina Gaslini, Member of the European Reference Network EpiCARE, Genoa, Italy
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Child and Maternal Health (DINOGMI), University of Genoa, Genoa, Italy
| | - Marcus Ng
- Biomedical Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
- Section of Neurology, University of Manitoba, Winnipeg, Manitoba, Canada
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Simeone KA, Martenz DM, Iyer SH, Booth CP, Herr SE, Matthews SA, Draves SB, Heinemann LL, Greenberg PL, Lhatoo SD, Donner E, Simeone TA. Personalization of SUDEP risk: A survey of transient subclinical comorbid changes. Epilepsy Res 2024; 199:107259. [PMID: 38086218 DOI: 10.1016/j.eplepsyres.2023.107259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 10/29/2023] [Accepted: 11/13/2023] [Indexed: 01/13/2024]
Abstract
OBJECTIVE Preclinical data report within subject modifiable ailments emerge weeks prior to SUDEP, including sleep disorders and cardiorespiratory changes; findings which support anecdotal clinical data. Here, we bridge preclinical findings with future clinical/preclinical studies, and survey whether caretakers or family members of victims noticed transient changes prior to SUDEP. The aim of this pilot study is to identify potential modifiable changes that may synergistically increase SUDEP risk for future research. METHODS A mobile electronic survey was posted on SUDEP community websites. The survey queried whether changes in seizures, sleep, physical well-being, emotional well-being, cognition, breathing, or heart rate were noticed before SUDEP. RESULTS The most profound finding was that 85% of victims had multiple transient ailments prior to SUDEP. Changes in seizures (28/54), and sleep (30/58) occurred in more than 50% of the victims and represent the most influential changes identified. The second and third most influential changes were a reduction in physical well-being (25/57) and emotional well-being (26/56). Changes were observed within the last two months of life in approximately one third of the cases, and more than four months prior to SUDEP in approximately one third of cases, indicating a potential time frame for proactive preventative strategies. Respondents also noted changes in cognition (16/55), breathing (9/54) or heart rate (8/55). Data indicate these changes may be associated with increased SUDEP risk within subject. Study limitations include the responses were based on memory, there was a potential for data to be over reported, and caretakers were not prompted to observe changes a priori, thus some existing changes may have gone unnoticed. SIGNIFICANCE Data support the preclinical findings that transient, subclinical (i.e., not severe enough to require medical intervention), modifiable ailments may increase risk of SUDEP. This suggests that just as an epilepsy type can change over a lifetime and epilepsy type-specific treatments can reduce SUDEP risk, further personalization of SUDEP risk will improve our understanding as to whether variables contribute to risk differently across lifespan. Thus, with a dynamic capacity to change, differing factors may contribute to the distribution of risk probability within an individual at any given time. Understanding whether different combinations of transient changes are specific to epilepsy type, age, or sex needs to be determined to move the field forward in hopes of developing a personalized approach to preventative strategies.
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Affiliation(s)
- Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States.
| | | | - Shruthi H Iyer
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Cameron P Booth
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Shelby E Herr
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Stephanie A Matthews
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Samantha B Draves
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Laura L Heinemann
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Pierce L Greenberg
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Samden D Lhatoo
- Department of Neurology, University of Texas Health Science Center at Houston John P and Katherine G McGovern Medical School, United States
| | - Elizabeth Donner
- Department of Paediatrics, Division of Neurology, Hospital for Sick Children, Canada
| | - Timothy A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
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Simeone KA. SUDEP: A Local Low Pressure [pO 2] System Makes It Hard to Breathe. Epilepsy Curr 2023; 23:327-329. [PMID: 37901771 PMCID: PMC10601030 DOI: 10.1177/15357597231186914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023] Open
Abstract
Sudden Unexpected Death in Epilepsy Is Prevented by Blocking Postictal Hypoxia George AG, Farrell JS, Colangeli R, Wall AK, Gom RC, Kesler MT, Rodriguez de la Hoz C, Villa BR, Perera T, Rho JM, Kurrasch D, Teskey GC. Neuropharmacology . 2023;231:109513. doi:10.1016/j.neuropharm.2023.109513 . PMID: 36948357 Epilepsy is at times a fatal disease. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality in people with intractable epilepsy and is defined by exclusion; non-accidental, non-toxicologic, and non-anatomic causes of death. While SUDEP often follows a bilateral tonic-clonic seizure, the mechanisms that ultimately lead to terminal apnea and then asystole remain elusive and there is a lack of preventative treatments. Based on the observation that discrete seizures lead to local and postictal vasoconstriction, resulting in hypoperfusion, hypoxia and behavioural disturbances in the forebrain we reasoned those similar mechanisms may play a role in SUDEP when seizures invade the brainstem. Here we tested this neurovascular-based hypothesis of SUDEP in awake non-anesthetized mice by pharmacologically preventing seizure-induced vasoconstriction, with cyclooxygenase-2 or L-type calcium channel antagonists. In both acute and chronic mouse models of seizure-induced premature mortality, ibuprofen and nicardipine extended life while systemic drug levels remained high enough to be effective. We also examined the potential role of spreading depolarization in the acute model of seizure-induced premature mortality. These data provide a proof-of-principle for the neurovascular hypothesis of SUDEP rather than spreading depolarization and the use of currently available drugs to prevent it.
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Affiliation(s)
- Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine
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Berteotti C, Calvello C, Liguori C. Role of the orexin system in the bidirectional relation between sleep and epilepsy: New chances for patients with epilepsy by the antagonism to orexin receptors? Epilepsia 2023; 64:1991-2005. [PMID: 37212716 DOI: 10.1111/epi.17661] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 05/19/2023] [Accepted: 05/19/2023] [Indexed: 05/23/2023]
Abstract
Epilepsy is a common neurological disorder, affecting patients of all ages, reducing the quality of life, and associated with several comorbidities. Sleep impairment is a frequent condition in patients with epilepsy (PWE), and the relation between sleep and epilepsy has been considered bidirectional, as one can significantly influence the other, and vice versa. The orexin system was described more than 20 years ago and is implicated in several neurobiological functions other than in controlling the sleep-wake cycle. Considering the relation between epilepsy and sleep, and the significant contribution of the orexin system in regulating the sleep-wake cycle, it is conceivable that the orexin system may be affected in PWE. Preclinical studies investigated the impact of the orexin system on epileptogenesis and the effect of orexin antagonism on seizures in animal models. Conversely, clinical studies are few and propose heterogeneous results also considering the different methodological approaches to orexin levels quantification (cerebrospinal-fluid or blood samples). Because orexin system activity can be modulated by sleep, and considering the sleep impairment documented in PWE, the recently approved dual orexin receptor antagonists (DORAs) have been suggested for treating sleep impairment and insomnia in PWE. Accordingly, sleep improvement can be a therapeutic strategy for reducing seizures and better managing epilepsy. The present review analyzes the preclinical and clinical evidence linking the orexin system to epilepsy, and hypothesizes a model in which the antagonism to the orexin system by DORAs can improve epilepsy by both a direct and a sleep-mediated (indirect) effect.
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Affiliation(s)
- Chiara Berteotti
- Physiological Regulation in Sleeping Mice Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Carmen Calvello
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Claudio Liguori
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
- Epilepsy Center, Neurology Unit, University Hospital Tor Vergata, Rome, Italy
- Sleep Medicine Center, Neurology Unit, University Hospital Tor Vergata, Rome, Italy
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Faingold CL, Feng HJ. A unified hypothesis of SUDEP: Seizure-induced respiratory depression induced by adenosine may lead to SUDEP but can be prevented by autoresuscitation and other restorative respiratory response mechanisms mediated by the action of serotonin on the periaqueductal gray. Epilepsia 2023; 64:779-796. [PMID: 36715572 PMCID: PMC10673689 DOI: 10.1111/epi.17521] [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] [Received: 10/07/2022] [Revised: 01/20/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a major cause of death in people with epilepsy (PWE). Postictal apnea leading to cardiac arrest is the most common sequence of terminal events in witnessed cases of SUDEP, and postconvulsive central apnea has been proposed as a potential biomarker of SUDEP susceptibility. Research in SUDEP animal models has led to the serotonin and adenosine hypotheses of SUDEP. These neurotransmitters influence respiration, seizures, and lethality in animal models of SUDEP, and are implicated in human SUDEP cases. Adenosine released during seizures is proposed to be an important seizure termination mechanism. However, adenosine also depresses respiration, and this effect is mediated, in part, by inhibition of neuronal activity in subcortical structures that modulate respiration, including the periaqueductal gray (PAG). Drugs that enhance the action of adenosine increase postictal death in SUDEP models. Serotonin is also released during seizures, but enhances respiration in response to an elevated carbon dioxide level, which often occurs postictally. This effect of serotonin can potentially compensate, in part, for the adenosine-mediated respiratory depression, acting to facilitate autoresuscitation and other restorative respiratory response mechanisms. A number of drugs that enhance the action of serotonin prevent postictal death in several SUDEP models and reduce postictal respiratory depression in PWE. This effect of serotonergic drugs may be mediated, in part, by actions on brainstem sites that modulate respiration, including the PAG. Enhanced activity in the PAG increases respiration in response to hypoxia and other exigent conditions and can be activated by electrical stimulation. Thus, we propose the unifying hypothesis that seizure-induced adenosine release leads to respiratory depression. This can be reversed by serotonergic action on autoresuscitation and other restorative respiratory responses acting, in part, via the PAG. Therefore, we hypothesize that serotonergic or direct activation of this brainstem site may be a useful approach for SUDEP prevention.
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Affiliation(s)
- Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Anesthesia, Harvard Medical School, Boston, Massachusetts, USA
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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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Knez R, Niksic M, Omerovic E. Orexin/hypocretin system dysfunction in patients with Takotsubo syndrome: A novel pathophysiological explanation. Front Cardiovasc Med 2022; 9:1016369. [PMID: 36407467 PMCID: PMC9670121 DOI: 10.3389/fcvm.2022.1016369] [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: 08/10/2022] [Accepted: 10/05/2022] [Indexed: 09/19/2023] Open
Abstract
Takotsubo syndrome (TTS) is an acute heart failure syndrome. Emotional or physical stressors are believed to precipitate TTS, while the pathophysiological mechanism is not yet completely understood. During the coronavirus disease (COVID-19) pandemic, an increased incidence of TTS has been reported in some countries; however, the precise pathophysiological mechanism for developing TTS with acute COVID-19 infection is unknown. Nevertheless, observing the symptoms of COVID-19 might lead to new perspectives in understanding TTS pathophysiology, as some of the symptoms of the COVID-19 infection could be assessed in the context of an orexin/hypocretin-system dysfunction. Orexin/hypocretin is a cardiorespiratory neuromodulator that acts on two orexin receptors widely distributed in the brain and peripheral tissues. In COVID-19 patients, autoantibodies against one of these orexin receptors have been reported. Orexin-system dysfunction affects a variety of systems in an organism. Here, we review the influence of orexin-system dysfunction on the cardiovascular system to propose its connection with TTS. We propose that orexin-system dysfunction is a potential novel explanation for the pathophysiology of TTS due to direct or indirect dynamics of orexin signaling, which could influence cardiac contractility. This is in line with the conceptualization of TTS as a cardiovascular syndrome rather than merely a cardiac abnormality or cardiomyopathy. To the best of our knowledge, this is the first publication to present a plausible connection between TTS and orexin-system dysfunction. We hope that this novel hypothesis will inspire comprehensive studies regarding orexin's role in TTS pathophysiology. Furthermore, confirmation of this plausible pathophysiological mechanism could contribute to the development of orexin-based therapeutics in the treatment and prevention of TTS.
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Affiliation(s)
- Rajna Knez
- Gillberg Neuropsychiatry Centre, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Research and Development, Department of Women's and Child Health, Skaraborg Hospital, Skövde, Sweden
- Institution for Health, School of Health Sciences, University of Skövde, Skövde, Sweden
| | - Milan Niksic
- Department of Cardiology, Skaraborg Hospital, Skövde, Sweden
| | - Elmir Omerovic
- Department of Molecular and Clinical Medicine/Cardiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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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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Hampson JP, Lacuey N, Rani MRS, Hampson JS, Simeone KA, Simeone TA, Narayana PA, Lemieux L, Lhatoo SD. Functional MRI Correlates of Carbon Dioxide Chemosensing in Persons With Epilepsy. Front Neurol 2022; 13:896204. [PMID: 35873766 PMCID: PMC9301231 DOI: 10.3389/fneur.2022.896204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/03/2022] [Indexed: 11/17/2022] Open
Abstract
Objectives Sudden unexpected death in epilepsy (SUDEP) is a catastrophic epilepsy outcome for which there are no reliable premortem imaging biomarkers of risk. Percival respiratory depression is seen in monitored SUDEP and near SUDEP cases, and abnormal chemosensing of raised blood carbon dioxide (CO2) is thought to contribute. Damage to brainstem respiratory control and chemosensing structures has been demonstrated in structural imaging and neuropathological studies of SUDEP. We hypothesized that functional MRI (fMRI) correlates of abnormal chemosensing are detectable in brainstems of persons with epilepsy (PWE) and are different from healthy controls (HC). Methods We analyzed fMRI BOLD activation and brain connectivity in 10 PWE and 10 age- and sex-matched HCs during precisely metered iso-oxic, hypercapnic breathing challenges. Segmented brainstem responses were of particular interest, along with characterization of functional connectivity metrics between these structures. Regional BOLD activations during hypercapnic challenges were convolved with hemodynamic responses, and the resulting activation maps were passed on to group-level analyses. For the functional connectivity analysis, significant clusters from BOLD results were used as seeds. Each individual seed time-series activation map was extracted for bivariate correlation coefficient analyses to study changes in brain connectivity between PWE and HCs. Results (1) Greater brainstem BOLD activations in PWE were observed compared to HC during hypercapnic challenges in several structures with respiratory/chemosensing properties. Group comparison between PWE vs. HC showed significantly greater activation in the dorsal raphe among PWE (p < 0.05) compared to HCs. (2) PWE had significantly greater seed-seed connectivity and recruited more structures during hypercapnia compared to HC. Significance The results of this study show that BOLD responses to hypercapnia in human brainstem are detectable and different in PWE compared to HC. Increased dorsal raphe BOLD activation in PWE and increased seed-seed connectivity between brainstem and adjacent subcortical areas may indicate abnormal chemosensing in these individuals. Imaging investigation of brainstem respiratory centers involved in respiratory regulation in PWE is an important step toward identifying suspected dysfunction of brainstem breathing control that culminates in SUDEP and deserve further study as potential imaging SUDEP biomarkers.
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Affiliation(s)
- Johnson P. Hampson
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Nuria Lacuey
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - MR Sandhya Rani
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Jaison S. Hampson
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Kristina A. Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, United States
| | - Timothy A. Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, United States
| | - Ponnada A. Narayana
- Department of Diagnostic and Interventional Imaging, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Louis Lemieux
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Samden D. Lhatoo
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
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Liu B, Qiao L, Liu K, Liu J, Piccinni-Ash TJ, Chen ZF. Molecular and neural basis of pleasant touch sensation. Science 2022; 376:483-491. [PMID: 35482870 DOI: 10.1126/science.abn2479] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Pleasant touch provides emotional and psychological support that helps mitigate social isolation and stress. However, the underlying mechanisms remain poorly understood. Using a pleasant touch-conditioned place preference (PT-CPP) test, we show that genetic ablation of spinal excitatory interneurons expressing prokineticin receptor 2 (PROKR2), or its ligand PROK2 in sensory neurons, abolishes PT-CPP without impairing pain and itch behaviors in mice. Mutant mice display profound impairments in stress response and prosocial behaviors. Moreover, PROKR2 neurons respond most vigorously to gentle stroking and encode reward value. Collectively, we identify PROK2 as a long-sought neuropeptide that encodes and transmits pleasant touch to spinal PROKR2 neurons. These findings may have important implications for elucidating mechanisms by which pleasant touch deprivation contributes to social avoidance behavior and mental disorders.
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Affiliation(s)
- Benlong Liu
- Center for the Study of Itch and Sensory Disorders and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lina Qiao
- Center for the Study of Itch and Sensory Disorders and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kun Liu
- Center for the Study of Itch and Sensory Disorders and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Juan Liu
- Center for the Study of Itch and Sensory Disorders and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tyler J Piccinni-Ash
- Center for the Study of Itch and Sensory Disorders and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zhou-Feng Chen
- Center for the Study of Itch and Sensory Disorders and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Departments of Medicine, Psychiatry, and Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
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12
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Abstract
PURPOSE OF REVIEW Sudden unexpected death in epilepsy (SUDEP) is a major contributor to premature mortality in people with epilepsy. This review provides an update on recent findings on the epidemiology of SUDEP, clinical risk factors and potential mechanisms. RECENT FINDINGS The overall risk rate of SUDEP is approximately 1 per 1000 patients per year in the general epilepsy population and that children and older adults have a similar incidence. Generalized convulsive seizures (GCS), perhaps through their effects on brainstem cardiopulmonary networks, can cause significant postictal respiratory and autonomic dysfunction though other mechanisms likely exist as well. Work in animal models of SUDEP has identified multiple neurotransmitter systems, which may be future targets for pharmacological intervention. There are also chronic functional and structural changes in autonomic function in patients who subsequently die from SUDEP suggesting that some SUDEP risk is dynamic. Modifiable risks for SUDEP include GCS seizure frequency, medication adherence and nighttime supervision. SUMMARY Current knowledge of SUDEP risk factors has identified multiple targets for SUDEP prevention today as we await more specific therapeutic targets that are emerging from translational research studies.
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Affiliation(s)
- Daniel Friedman
- NYU Grossman School of Medicine, Department of Neurology, 223 East 34th Street, New York, New York, USA
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13
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Buchanan GF. Tuning the Wave: Controlling Spreading Depolarization with Activation/Inactivation of Kv7.2. Epilepsy Curr 2021; 21:444-446. [PMID: 34924853 PMCID: PMC8652316 DOI: 10.1177/15357597211043730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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14
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Deodhar M, Matthews SA, Thomas B, Adamian L, Mattes S, Wells T, Zieba B, Simeone KA, Simeone TA. Pharmacoresponsiveness of spontaneous recurrent seizures and the comorbid sleep disorder of epileptic Kcna1-null mice. Eur J Pharmacol 2021; 913:174656. [PMID: 34838797 DOI: 10.1016/j.ejphar.2021.174656] [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: 08/18/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 11/24/2022]
Abstract
Drug resistant epilepsy affects ∼30% of people with epilepsy and is associated with epilepsy syndromes with frequent and multiple types of seizures, lesions or cytoarchitectural abnormalities, increased risk of mortality and comorbidities such as cognitive impairment and sleep disorders. A limitation of current preclinical models is that spontaneous seizures with comorbidities take time to induce and test, thus making them low-throughput. Kcna1-null mice exhibit all the characteristics of drug resistant epilepsy with spontaneous seizures and comorbidities occurring naturally; thus, we aimed to determine whether they also demonstrate pharmacoresistanct seizures and the impact of medications on their sleep disorder comorbidity. In this exploratory study, Kcna1-null mice were treated with one of four conventional antiseizure medications, carbamazepine, levetiracetam, phenytoin, and phenobarbital using a moderate throughput protocol (vehicle for 2 days followed by 2 days of treatment with high therapeutic doses selected based on published data in the 6 Hz model of pharmacoresistant seizures). Spontaneous recurrent seizures and vigilance states were recorded with video-EEG/EMG. Carbamazepine, levetiracetam and phenytoin had partial efficacy (67%, 75% and 33% were seizure free, respectively), whereas phenobarbital was fully efficacious and conferred seizure freedom to all mice. Thus, seizures of Kcna1-null mice appear to be resistant to three of the drugs tested. Levetiracetam failed to affect sleep architecture, carbamazepine and phenytoin had moderate effects, and phenobarbital, as predicted, restored sleep architecture. Data suggest Kcna1-null mice may be a moderate throughput model of drug resistant epilepsy useful in determining mechanisms of pharmacoresistance and testing novel therapeutic strategies.
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Affiliation(s)
- Malavika Deodhar
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Stephanie A Matthews
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Brittany Thomas
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Leena Adamian
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Sarah Mattes
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Tabitha Wells
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Brianna Zieba
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Kristina A Simeone
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Timothy A Simeone
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA.
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15
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Sahly AN, Shevell M, Sadleir LG, Myers KA. SUDEP risk and autonomic dysfunction in genetic epilepsies. Auton Neurosci 2021; 237:102907. [PMID: 34773737 DOI: 10.1016/j.autneu.2021.102907] [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: 02/28/2021] [Revised: 10/11/2021] [Accepted: 11/06/2021] [Indexed: 01/02/2023]
Abstract
The underlying pathophysiology of sudden unexpected death in epilepsy (SUDEP) remains unclear. This phenomenon is likely multifactorial, and there is considerable evidence that genetic factors play a role. There are certain genetic causes of epilepsy in which the risk of SUDEP appears to be increased relative to epilepsy overall. For individuals with pathogenic variants in genes including SCN1A, SCN1B, SCN8A, SCN2A, GNB5, KCNA1 and DEPDC5, there are varying degrees of evidence to suggest an increased risk for sudden death. Why the risk for sudden death is higher is not completely clear; however, in many cases pathogenic variants in these genes are also associated with autonomic dysfunction, which is hypothesized as a contributing factor to SUDEP. We review the evidence for increased SUDEP risk for patients with epilepsy due to pathogenic variants in these genes, and also discuss what is known about autonomic dysfunction in these contexts.
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Affiliation(s)
- Ahmed N Sahly
- Division of Neurology, Department of Pediatrics, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada; Department of Neurosciences, King Faisal Specialist Hospital & Research Centre, Jeddah, Saudi Arabia
| | - Michael Shevell
- Division of Neurology, Department of Pediatrics, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada; Department of Neurology and Neurosurgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada; Research Institute of the McGill University Medical Centre, Montreal, Quebec, Canada
| | - Lynette G Sadleir
- Department of Paediatrics and Child Health, University of Otago, Wellington, New Zealand
| | - Kenneth A Myers
- Division of Neurology, Department of Pediatrics, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada; Department of Neurology and Neurosurgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada; Research Institute of the McGill University Medical Centre, Montreal, Quebec, Canada.
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16
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Nagata S, Fujiwara K, Kuga K, Ozaki H. Prediction of GABA receptor antagonist-induced convulsion in cynomolgus monkeys by combining machine learning and heart rate variability analysis. J Pharmacol Toxicol Methods 2021; 112:107127. [PMID: 34619314 DOI: 10.1016/j.vascn.2021.107127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 09/30/2021] [Accepted: 09/30/2021] [Indexed: 12/19/2022]
Abstract
Drug-induced convulsion is a severe adverse event; however, no useful biomarkers for it have been discovered. We propose a new method for predicting drug-induced convulsions in monkeys based on heart rate variability (HRV) and a machine learning technique. Because autonomic nervous activities are altered around the time of a convulsion and such alterations affect HRV, they may be predicted by monitoring HRV. In the proposed method, anomalous changes in multiple HRV parameters are monitored by means of a convulsion prediction model, and convulsion alarms are issued when abnormal changes in HRV are detected. The convulsion prediction model is constructed based on multivariate statistical process control (MSPC), a well-known anomaly detection algorithm in machine learning. In this study, HRV data were collected from four cynomolgus monkeys administered with multiple doses of pentylenetetrazol (PTZ) and picrotoxin (PTX), which are GABA receptor antagonists, as convulsant agents. In addition, low doses of pilocarpine (PILO) were administered as a negative control. Twelve HRV parameters in three hours after drug administration were monitored by means of the prediction model. The number and duration of convulsion alarms from HRV increased at medium and high doses of PTZ and PTX (1/3 or 1/4 of convulsion dose). On the other hand, the frequency of convulsion alarms did not increase with PILO. Although vomiting was observed in all drugs, convulsion alarms were not associated with the vomiting. Thus, convulsion alarms can be used as a biomarker for convulsions induced by GABA receptor antagonists.
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Affiliation(s)
- Shoya Nagata
- Department of Material Process Engineering, Nagoya University, Nagoya, Japan
| | - Koichi Fujiwara
- Department of Material Process Engineering, Nagoya University, Nagoya, Japan.
| | - Kazuhiro Kuga
- Drug Safety Research and Evaluation, Takeda Pharmaceutical Company Ltd., Kanagawa, Japan
| | - Harushige Ozaki
- Drug Safety Research and Evaluation, Takeda Pharmaceutical Company Ltd., Kanagawa, Japan
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17
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Akyüz E, Üner AK, Köklü B, Arulsamy A, Shaikh MF. Cardiorespiratory findings in epilepsy: A recent review on outcomes and pathophysiology. J Neurosci Res 2021; 99:2059-2073. [PMID: 34109651 DOI: 10.1002/jnr.24861] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/16/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022]
Abstract
Epilepsy is a debilitating disorder of uncontrollable recurrent seizures that occurs as a result of imbalances in the brain excitatory and inhibitory neuronal signals, that could stem from a range of functional and structural neuronal impairments. Globally, nearly 70 million people are negatively impacted by epilepsy and its comorbidities. One such comorbidity is the effect epilepsy has on the autonomic nervous system (ANS), which plays a role in the control of blood circulation, respiration and gastrointestinal function. These epilepsy-induced impairments in the circulatory and respiratory systems may contribute toward sudden unexpected death in epilepsy (SUDEP). Although, various hypotheses have been proposed regarding the role of epilepsy on ANS, the linking pathological mechanism still remains unclear. Channelopathies and seizure-induced damages in ANS-control brain structures were some of the causal/pathological candidates of cardiorespiratory comorbidities in epilepsy patients, especially in those who were drug resistant. However, emerging preclinical research suggest that neurotransmitter/receptor dysfunction and synaptic changes in the ANS may also contribute to the epilepsy-related autonomic disorders. Thus, pathological mechanisms of cardiorespiratory dysfunction should be elucidated by considering the modifications in anatomy and physiology of the autonomic system caused by seizures. In this regard, we present a comprehensive review of the current literature, both clinical and preclinical animal studies, on the cardiorespiratory findings in epilepsy and elucidate the possible pathological mechanisms of these findings, in hopes to prevent SUDEP especially in patients who are drug resistant.
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Affiliation(s)
- Enes Akyüz
- Department of Biophysics, Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Arda Kaan Üner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Betül Köklü
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Alina Arulsamy
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Mohd Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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18
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Buchanan GF, Gluckman BJ, Kalume FK, Lhatoo S, Maganti RK, Noebels JL, Simeone KA, Quigg MS, Pavlova MK. Proceedings of the Sleep and Epilepsy Workshop: Section 3 Mortality: Sleep, Night, and SUDEP. Epilepsy Curr 2021; 21:15357597211004556. [PMID: 33787378 PMCID: PMC8609595 DOI: 10.1177/15357597211004556] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy. Likely pathophysiological mechanisms include seizure-induced cardiac and respiratory dysregulation. A frequently identified feature in SUDEP cases is that they occur at night. This raises the question of a role for sleep state in regulating of SUDEP. An association with sleep has been identified in a number of studies with patients and in animal models. The focus of this section of the Sleep and Epilepsy Workshop was on identifying and understanding the role for sleep and time of day in the pathophysiology of SUDEP.
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Affiliation(s)
- Gordon F. Buchanan
- Department of Neurology and Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Bruce J. Gluckman
- Department of Engineering Science & Mechanics, Penn State University, University Park, PA, USA
- Department of Neurosurgery, Penn State University, University Park, PA, USA
- Department of Biomedical Engineering, Penn State University, University Park, PA, USA
| | - Franck K. Kalume
- Department of Neurological Surgery, University of Washington and Seattle Children’s Research Institute, Seattle, WA, USA
| | - Samden Lhatoo
- Department of Neurology, University of Texas McGovern Medical School, Houston, TX, USA
| | - Rama K. Maganti
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Jeffrey L. Noebels
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Kristina A. Simeone
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Mark S. Quigg
- Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Milena K. Pavlova
- Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
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19
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Jennum PJ, Plazzi G, Silvani A, Surkin LA, Dauvilliers Y. Cardiovascular disorders in narcolepsy: Review of associations and determinants. Sleep Med Rev 2021; 58:101440. [PMID: 33582582 DOI: 10.1016/j.smrv.2021.101440] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/31/2020] [Accepted: 11/02/2020] [Indexed: 10/22/2022]
Abstract
Narcolepsy type 1 (NT1) is a lifelong disorder of sleep-wake dysregulation defined by clinical symptoms, neurophysiological findings, and low hypocretin levels. Besides a role in sleep, hypocretins are also involved in regulation of heart rate and blood pressure. This literature review examines data on the autonomic effects of hypocretin deficiency and evidence about how narcolepsy is associated with multiple cardiovascular risk factors and comorbidities, including cardiovascular disease. An important impact in NT1 is lack of nocturnal blood pressure dipping, which has been associated with mortality in the general population. Hypertension is also prevalent in NT1. Furthermore, disrupted nighttime sleep and excessive daytime sleepiness, which are characteristic of narcolepsy, may increase cardiovascular risk. Patients with narcolepsy also often present with other comorbidities (eg, obesity, diabetes, depression, other sleep disorders) that may contribute to increased cardiovascular risk. Management of multimorbidity in patients with narcolepsy should include regular assessment of cardiovascular health (including ambulatory blood pressure monitoring), mitigation of cardiovascular risk factors (eg, cessation of smoking and other lifestyle changes, sleep hygiene, and pharmacotherapy), and prescription of a regimen of narcolepsy medications that balances symptomatic benefits with cardiovascular safety.
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Affiliation(s)
- Poul Jørgen Jennum
- Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark.
| | - Giuseppe Plazzi
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio-Emilia, Modena, Italy; IRCCS, Istituto delle Scienze Neurologiche, Bologna, Italy
| | - Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Lee A Surkin
- Empire Sleep Medicine, New York, NY, United States
| | - Yves Dauvilliers
- Sleep and Wake Disorders Centre, Department of Neurology, Gui de Chauliac Hospital, Montpellier, France; University of Montpellier, INSERM U1061, Montpellier, France
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20
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Trosclair K, Si M, Watts M, Gautier NM, Voigt N, Traylor J, Bitay M, Baczko I, Dobrev D, Hamilton KA, Bhuiyan MS, Dominic P, Glasscock E. Kv1.1 potassium channel subunit deficiency alters ventricular arrhythmia susceptibility, contractility, and repolarization. Physiol Rep 2021; 9:e14702. [PMID: 33427415 PMCID: PMC7798052 DOI: 10.14814/phy2.14702] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 12/11/2022] Open
Abstract
Epilepsy-associated Kv1.1 voltage-gated potassium channel subunits encoded by the Kcna1 gene have traditionally been considered absent in heart, but recent studies reveal they are expressed in cardiomyocytes where they could regulate intrinsic cardiac electrophysiology. Although Kv1.1 now has a demonstrated functional role in atria, its role in the ventricles has never been investigated. In this work, electrophysiological, histological, and gene expression approaches were used to explore the consequences of Kv1.1 deficiency in the ventricles of Kcna1 knockout (KO) mice at the organ, cellular, and molecular levels to determine whether the absence of Kv1.1 leads to ventricular dysfunction that increases the risk of premature or sudden death. When subjected to intracardiac pacing, KO mice showed normal baseline susceptibility to inducible ventricular arrhythmias (VA) but resistance to VA under conditions of sympathetic challenge with isoproterenol. Echocardiography revealed cardiac contractile dysfunction manifesting as decreased ejection fraction and fractional shortening. In whole-cell patch-clamp recordings, KO ventricular cardiomyocytes exhibited action potential prolongation indicative of impaired repolarization. Imaging, histological, and transcript analyses showed no evidence of structural or channel gene expression remodeling, suggesting that the observed deficits are likely electrogenic due to Kv1.1 deficiency. Immunoblots of patient heart samples detected the presence of Kv1.1 at relatively high levels, implying that Kv1.1 contributes to human cardiac electrophysiology. Taken together, this work describes an important functional role for Kv1.1 in ventricles where its absence causes repolarization and contractility deficits but reduced susceptibility to arrhythmia under conditions of sympathetic drive.
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Affiliation(s)
- Krystle Trosclair
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Man Si
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Megan Watts
- Department of Internal MedicineSection of CardiologyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Nicole M. Gautier
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Niels Voigt
- Institute of Pharmacology and ToxicologyUniversity Medical Center GoettingenGoettingenGermany
- DZHK (German Center for Cardiovascular Research)GöttingenGermany
| | - James Traylor
- Department of PathologyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Miklós Bitay
- Department of Cardiac Surgery2nd Department of Medicine and Cardiology CenterUniversity of SzegedSzegedHungary
| | - Istvan Baczko
- Department of Pharmacology and PharmacotherapyInterdisciplinary Excellence CentreUniversity of SzegedSzegedHungary
| | - Dobromir Dobrev
- Institute of PharmacologyWest German Heart and Vascular CenterUniversity Duisburg‐EssenEssenGermany
| | - Kathryn A. Hamilton
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Md. Shenuarin Bhuiyan
- Department of PathologyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Paari Dominic
- Department of Internal MedicineSection of CardiologyLouisiana State University Health Sciences CenterShreveportLAUSA
| | - Edward Glasscock
- Department of Cellular Biology & AnatomyLouisiana State University Health Sciences CenterShreveportLAUSA
- Department of Biological SciencesSouthern Methodist UniversityDallasTXUSA
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