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Gu J, Shao W, Liu L, Wang Y, Yang Y, Zhang Z, Wu Y, Xu Q, Gu L, Zhang Y, Shen Y, Zhao H, Zeng C, Zhang H. Challenges and future directions of SUDEP models. Lab Anim (NY) 2024:10.1038/s41684-024-01426-y. [PMID: 39187733 DOI: 10.1038/s41684-024-01426-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 08/02/2024] [Indexed: 08/28/2024]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among patients with epilepsy, causing a global public health burden. The underlying mechanisms of SUDEP remain elusive, and effective prevention or treatment strategies require further investigation. A major challenge in current SUDEP research is the lack of an ideal model that maximally mimics the human condition. Animal models are important for revealing the potential pathogenesis of SUDEP and preventing its occurrence; however, they have potential limitations due to species differences that prevent them from precisely replicating the intricate physiological and pathological processes of human disease. This Review provides a comprehensive overview of several available SUDEP animal models, highlighting their pros and cons. More importantly, we further propose the establishment of an ideal model based on brain-computer interfaces and artificial intelligence, hoping to offer new insights into potential advancements in SUDEP research. In doing so, we hope to provide valuable information for SUDEP researchers, offer new insights into the pathogenesis of SUDEP and open new avenues for the development of strategies to prevent SUDEP.
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Affiliation(s)
- JiaXuan Gu
- Department of Anesthesiology, the Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - WeiHui Shao
- Department of Anesthesiology, the Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Lu Liu
- Department of Anesthesiology, Zhejiang University School of Medicine, Hangzhou, China
| | - YuLing Wang
- Department of Anesthesiology, the Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yue Yang
- Department of Anesthesiology, the Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - ZhuoYue Zhang
- Department of Anesthesiology, Zhejiang University School of Medicine, Hangzhou, China
| | - YaXuan Wu
- Department of Anesthesiology, the Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Qing Xu
- Department of Anesthesiology, Zhejiang University School of Medicine, Hangzhou, China
| | - LeYuan Gu
- Department of Anesthesiology, the Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - YuanLi Zhang
- Department of Anesthesiology, the Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yue Shen
- Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Westlake University School of Medicine, Hangzhou, China
| | - HaiTing Zhao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Chang Zeng
- Health Management Center, Xiangya Hospital, Central South University, Changsha, China
| | - HongHai Zhang
- Department of Anesthesiology, the Fourth Clinical School of Medicine, Zhejiang Chinese Medical University, Hangzhou, China.
- Department of Anesthesiology, Zhejiang University School of Medicine, Hangzhou, China.
- Department of Anesthesiology, Affiliated Hangzhou First People's Hospital, Westlake University School of Medicine, Hangzhou, China.
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Guo J, Min D, Farrell EK, Zhou Y, Faingold CL, Cotten JF, Feng HJ. Enhancing the action of serotonin by three different mechanisms prevents spontaneous seizure-induced mortality in Dravet mice. Epilepsia 2024; 65:1791-1800. [PMID: 38593237 PMCID: PMC11166528 DOI: 10.1111/epi.17966] [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: 08/17/2023] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 04/11/2024]
Abstract
OBJECTIVE Sudden unexpected death in epilepsy (SUDEP) is an underestimated complication of epilepsy. Previous studies have demonstrated that enhancement of serotonergic neurotransmission suppresses seizure-induced sudden death in evoked seizure models. However, it is unclear whether elevated serotonin (5-HT) function will prevent spontaneous seizure-induced mortality (SSIM), which is characteristic of human SUDEP. We examined the effects of 5-HT-enhancing agents that act by three different pharmacological mechanisms on SSIM in Dravet mice, which exhibit a high incidence of SUDEP, modeling human Dravet syndrome. METHODS Dravet mice of both sexes were evaluated for spontaneous seizure characterization and changes in SSIM incidence induced by agents that enhance 5-HT-mediated neurotransmission. Fluoxetine (a selective 5-HT reuptake inhibitor), fenfluramine (a 5-HT releaser and agonist), SR 57227 (a specific 5-HT3 receptor agonist), or saline (vehicle) was intraperitoneally administered over an 8-day period in Dravet mice, and the effect of these treatments on SSIM was examined. RESULTS Spontaneous seizures in Dravet mice generally progressed from wild running to tonic seizures with or without SSIM. Fluoxetine at 30 mg/kg, but not at 20 or 5 mg/kg, significantly reduced SSIM compared with the vehicle control. Fenfluramine at 1-10 mg/kg, but not .2 mg/kg, fully protected Dravet mice from SSIM, with all mice surviving. Compared with the vehicle control, SR 57227 at 20 mg/kg, but not at 10 or 5 mg/kg, significantly lowered SSIM. The effect of these drugs on SSIM was independent of sex. SIGNIFICANCE Our data demonstrate that elevating serotonergic function by fluoxetine, fenfluramine, or SR 57227 significantly reduces or eliminates SSIM in Dravet mice in a sex-independent manner. These findings suggest that deficits in serotonergic neurotransmission likely play an important role in the pathogenesis of SSIM, and fluoxetine and fenfluramine, which are US Food and Drug Administration-approved medications, may potentially prevent SUDEP in at-risk patients.
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Affiliation(s)
- Jialing Guo
- National Health Commission Key Laboratory of Birth Defect Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Anesthesia, Harvard Medical School, Boston, MA, USA
| | - Daniel Min
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Emory K. Farrell
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Yupeng Zhou
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Carl L. Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Joseph F. Cotten
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Anesthesia, Harvard Medical School, Boston, MA, USA
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Anesthesia, Harvard Medical School, Boston, MA, USA
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Pan Y, Tan Z, Guo J, Feng HJ. 5-HT receptors exert differential effects on seizure-induced respiratory arrest in DBA/1 mice. PLoS One 2024; 19:e0304601. [PMID: 38820310 PMCID: PMC11142501 DOI: 10.1371/journal.pone.0304601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 05/14/2024] [Indexed: 06/02/2024] Open
Abstract
Both clinical and animal studies demonstrated that seizure-induced respiratory arrest (S-IRA) contributes importantly to sudden unexpected death in epilepsy (SUDEP). It has been shown that enhancing serotonin (5-HT) function relieves S-IRA in animal models of SUDEP, including DBA/1 mice. Direct activation of 5-HT3 and 5-HT4 receptors suppresses S-IRA in DBA/1 mice, indicating that these receptors are involved in S-IRA. However, it remains unknown if other subtypes of 5-HT receptors are implicated in S-IRA in DBA/1 mice. In this study, we investigated the action of an agonist of the 5-HT1A (8-OH-DPAT), 5-HT2A (TCB-2), 5-HT2B (BW723C86), 5-HT2C (MK-212), 5-HT6 (WAY-208466) and 5-HT7 (LP-211) receptor on S-IRA in DBA/1 mice. An agonist of the 5-HT receptor or a vehicle was intraperitoneally administered 30 min prior to acoustic simulation, and the effect of each drug/vehicle on the incidence of S-IRA was videotaped for offline analysis. We found that the incidence of S-IRA was significantly reduced by TCB-2 at 10 mg/kg (30%, n = 10; p < 0.01, Fisher's exact test) but was not altered by other agonists compared with the corresponding vehicle controls in DBA/1 mice. Our data demonstrate that 5-HT2A receptors are implicated in S-IRA, and 5-HT1A, 5-HT2B, 5-HT2C, 5-HT6 and 5-HT7 receptors are not involved in S-IRA in DBA/1 mice.
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Affiliation(s)
- Yundan Pan
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, China
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Zheren Tan
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States of America
- Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Jialing Guo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States of America
- National Health Commission Key Laboratory of Birth Defect Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States of America
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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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Sun X, Lv Y, Lin J. The mechanism of sudden unexpected death in epilepsy: A mini review. Front Neurol 2023; 14:1137182. [PMID: 36815002 PMCID: PMC9939452 DOI: 10.3389/fneur.2023.1137182] [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: 01/04/2023] [Accepted: 01/20/2023] [Indexed: 02/08/2023] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is defined as a sudden, unexpected, non-traumatic, non-drowning death in a person with epilepsy. SUDEP is generally considered to result from seizure-related cardiac dysfunction, respiratory depression, autonomic nervous dysfunction, or brain dysfunction. Frequency of generalized tonic clonic seizures (GTCS), prone posture, and refractory epilepsy are considered risk factors. SUDEP has also been associated with inherited cardiac ion channel disease and severe obstructive sleep apnea. Most previous studies of SUDEP mechanisms have focused on cardiac and respiratory dysfunction and imbalance of the neural regulatory system. Cardiac-related mechanisms include reduction in heart rate variability and prolongation of QT interval, which can lead to arrhythmias. Laryngospasm and amygdala activation may cause obstructive and central apnea, respectively. Neural mechanisms include impairment of 5-HT and adenosine neuromodulation. The research to date regarding molecular mechanisms of SUDEP is relatively limited. Most studies have focused on p-glycoprotein, catecholamines, potassium channels, and the renin-angiotensin system, all of which affect cardiac and respiratory function.
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Affiliation(s)
- Xinyi Sun
- School of Basic Medical Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Yehui Lv
- School of Basic Medical Sciences, Shanghai University of Medicine and Health Sciences, Shanghai, China,Institute of Wound Prevention and Treatment, Shanghai University of Medicine and Health Sciences, Shanghai, China,*Correspondence: Yehui Lv ✉
| | - Jian Lin
- Institute of Wound Prevention and Treatment, Shanghai University of Medicine and Health Sciences, Shanghai, China,Chongming Hospital Affiliated to Shanghai University of Medicine and Health Sciences, Shanghai, China
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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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7
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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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Xia M, Owen B, Chiang J, Levitt A, Preisinger K, Yan WW, Huffman R, Nobis WP. Disruption of Synaptic Transmission in the Bed Nucleus of the Stria Terminalis Reduces Seizure-Induced Death in DBA/1 Mice and Alters Brainstem E/I Balance. ASN Neuro 2022; 14:17590914221103188. [PMID: 35611439 PMCID: PMC9136462 DOI: 10.1177/17590914221103188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in refractory epilepsy patients. Accumulating evidence from recent human studies and animal models suggests that seizure-related respiratory arrest may be important for initiating cardiorespiratory arrest and death. Prior evidence suggests that apnea onset can coincide with seizure spread to the amygdala and that stimulation of the amygdala can reliably induce apneas in epilepsy patients, potentially implicating amygdalar regions in seizure-related respiratory arrest and subsequent postictal hypoventilation and cardiorespiratory death. This study aimed to determine if an extended amygdalar structure, the dorsal bed nucleus of the stria terminalis (dBNST), is involved in seizure-induced respiratory arrest (S-IRA) and death using DBA/1 mice, a mouse strain which has audiogenic seizures (AGS) and a high incidence of postictal respiratory arrest and death. The presence of S-IRA significantly increased c-Fos expression in the dBNST of DBA/1 mice. Furthermore, disruption of synaptic output from the dBNST via viral-induced tetanus neurotoxin (TeNT) significantly improved survival following S-IRA in DBA/1 mice without affecting baseline breathing or hypercapnic (HCVR) and hypoxic ventilatory response (HVR). This disruption in the dBNST resulted in changes to the balance of excitatory/inhibitory (E/I) synaptic events in the downstream brainstem regions of the lateral parabrachial nucleus (PBN) and the periaqueductal gray (PAG). These findings suggest that the dBNST is a potential subcortical forebrain site necessary for the mediation of S-IRA, potentially through its outputs to brainstem respiratory regions.
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Affiliation(s)
| | | | | | | | | | | | | | - William P. Nobis
- Department of Neurology, Vanderbilt University Medical Center, 6130A MRB 3/Bio Sci Building, 465 21st Ave S, Nashville, TN 37235, USA.
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Sourbron J, Lagae L. Serotonin receptors in epilepsy: novel treatment targets? Epilepsia Open 2022; 7:231-246. [PMID: 35075810 PMCID: PMC9159250 DOI: 10.1002/epi4.12580] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/08/2022] [Accepted: 01/20/2022] [Indexed: 11/24/2022] Open
Abstract
Despite the availability of over 30 antiseizure medications (ASMs), there is no “one size fits it all,” so there is a continuing search for novel ASMs. There are divergent data demonstrating that modulation of distinct serotonin (5‐hydroxytryptamine, 5‐HT) receptors subtypes could be beneficial in the treatment of epilepsy and its comorbidities, whereas only a few ASM, such as fenfluramine (FA), act via 5‐HT. There are 14 different 5‐HT receptor subtypes, and most epilepsy studies focus on one or a few of these subtypes, using different animal models and different ligands. We reviewed the available evidence of each 5‐HT receptor subtype using MEDLINE up to July 2021. Our search included medical subject heading (MeSH) and free terms of each “5‐HT subtype” separately and its relation to “epilepsy or seizures.” Most research underlines the antiseizure activity of 5‐HT1A,1D,2A,2C,3 agonism and 5‐HT6 antagonism. Consistently, FA, which has recently been approved for the treatment of seizures in Dravet syndrome, is an agonist of 5‐HT1D,2A,2C receptors. Even though each study focused on a distinct seizure/epilepsy type and generalization of different findings could lead to false interpretations, we believe that the available preclinical and clinical studies emphasize the role of serotonergic modulation, especially stimulation, as a promising avenue in epilepsy treatment.
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Affiliation(s)
- Jo Sourbron
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospital KU Leuven, Leuven, Belgium.,Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Lieven Lagae
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospital KU Leuven, Leuven, Belgium
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10
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Goldman AM. When Apnea Turns Terminal: When, How, Why? Epilepsy Curr 2021; 21:449-451. [PMID: 34924855 PMCID: PMC8652325 DOI: 10.1177/15357597211036815] [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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Guo J, Min D, Feng HJ. Genistein, a Natural Isoflavone, Alleviates Seizure-Induced Respiratory Arrest in DBA/1 Mice. Front Neurol 2021; 12:761912. [PMID: 34803895 PMCID: PMC8599950 DOI: 10.3389/fneur.2021.761912] [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: 08/20/2021] [Accepted: 10/13/2021] [Indexed: 11/25/2022] Open
Abstract
Objective: Sudden unexpected death in epilepsy (SUDEP) is a fatal event that ranks second in years of potential life lost among neurological disorders. Seizure-induced respiratory arrest (S-IRA) is the primary instigator leading to death in many SUDEP cases. However, there are currently no effective preventive strategies against S-IRA other than the seizure control. Therefore, it is critical to develop new avenues to prevent SUDEP by investigating the pharmacological interventions of S-IRA. In the present study, we examined the effect of genistein, an isoflavone found in various dietary vegetables, on the incidence of S-IRA in DBA/1 mice. Methods: DBA/1 mice exhibited generalized seizures and S-IRA when subjected to acoustic stimulation. Genistein was intraperitoneally administered alone or in combination with an adrenoceptor antagonist and a serotonin (5-HT) receptor antagonist, respectively. The effects of drug treatments on S-IRA incidence and seizure behaviors were examined. Results: The incidence of S-IRA in DBA/1 mice was significantly reduced 2 h after injection of genistein at 1–90 mg/kg as compared with that in the vehicle control. Genistein could block S-IRA without interfering with any component of seizures, especially at relatively lower dosages. The S-IRA-suppressing effect of genistein was reversed by an α2 adrenoceptor antagonist but was not altered by an α1 antagonist. The inhibitory effect of genistein on S-IRA was not affected by a 5-HT3 or 5-HT2A receptor antagonist. Significance: Our data show that genistein reduces S-IRA incidence and can specifically block S-IRA in DBA/1 mice. Its suppressing effect on S-IRA is dependent on activating α2 adrenoceptors. Our study suggests that genistein, a dietary supplement, is potentially useful to prevent SUDEP in at-risk patients.
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Affiliation(s)
- Jialing Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, United States.,Department of Anesthesia, Harvard Medical School, Boston, MA, United States
| | - Daniel Min
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, United States.,Department of Anesthesia, Harvard Medical School, Boston, MA, United States
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Zhang R, Tan Z, Niu J, Feng HJ. Adrenergic α2 receptors are implicated in seizure-induced respiratory arrest in DBA/1 mice. Life Sci 2021; 284:119912. [PMID: 34461082 PMCID: PMC8484063 DOI: 10.1016/j.lfs.2021.119912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 07/29/2021] [Accepted: 08/19/2021] [Indexed: 02/03/2023]
Abstract
AIMS Sudden unexpected death in epilepsy (SUDEP) is a serious and underestimated public health burden. Both clinical and animal studies show that seizure-induced respiratory arrest (S-IRA) is the primary cause of death in SUDEP. Our previous studies demonstrated that atomoxetine, a norepinephrine reuptake inhibitor (NRI), suppresses S-IRA in DBA/1 mice, suggesting that noradrenergic neurotransmission modulates S-IRA. However, it remains unclear which adrenoceptors are implicated in S-IRA in DBA/1 mice. MATERIALS AND METHODS Naïve DBA/1 mice exhibit a low incidence of S-IRA, but after primed by acoustic stimulation, they become consistently susceptible to S-IRA. Atomoxetine, adrenoceptor agonists, antagonists or vehicle was intraperitoneally (i.p.) administered alone or in combination, and the effects of drug treatments on S-IRA incidence and seizure behaviors were examined. KEY FINDINGS The incidence of S-IRA in primed DBA/1 mice was significantly reduced by clonidine, an α2 adrenoceptor agonist, as compared with that of the vehicle control. However, compared with the vehicle control, S-IRA was not altered by cirazoline, an α1 agonist. Consistent with previous reports, atomoxetine reduced S-IRA in primed DBA/1 mice. The suppressing effect of atomoxetine on S-IRA was prevented by injection of an α2 adrenoceptor antagonist, yohimbine or atipamezole, but not by prazosin, an α1 antagonist. Administration of α1 or α2 antagonists alone did not promote the incidence of S-IRA in nonprimed DBA/1 mice. SIGNIFICANCE These data demonstrate that noradrenergic neurotransmission modulates S-IRA predominantly via α2 adrenoceptors in DBA/1 mice, indicating that selective activation of α2 adrenoceptors can potentially prevent SUDEP.
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Affiliation(s)
- Rui Zhang
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan 750004, China
| | - Zheren Tan
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Jianguo Niu
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan 750004, China
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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Tupal S, Faingold CL. Serotonin 5-HT 4 receptors play a critical role in the action of fenfluramine to block seizure-induced sudden death in a mouse model of SUDEP. Epilepsy Res 2021; 177:106777. [PMID: 34601387 DOI: 10.1016/j.eplepsyres.2021.106777] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/25/2021] [Accepted: 09/21/2021] [Indexed: 11/28/2022]
Abstract
RATIONALE Our previous study showed that the recently approved anticonvulsant drug, fenfluramine, which enhances the release of serotonin (5-hydroxytryptamine, 5-HT) in the brain, prevents seizure-induced respiratory arrest (S-IRA) in the DBA/1 mouse model of sudden unexpected death in epilepsy (SUDEP). The present study examined the role of 5-HT receptor subtypes in mediating the effect of this agent by combined administration of fenfluramine with selective 5-HT receptor antagonists prior to seizure in DBA/1 mice. METHODS Fenfluramine (15 mg/kg, i.p.) was administered to primed DBA/1 mice, and audiogenic seizure (Sz) was induced 16 h later. Thirty min prior to Sz induction a selective antagonist acting on 5-HT1A, 5-HT2, 5-HT3 5-HT4, 5-HT5A, 5-HT6 or 5-HT7 receptors at a sub-toxic dose was administered, and changes in seizure-induced behaviors were evaluated. Follow-up studies examined the effect of administration of a 5-HT4 receptor agonist, BIMU 8, as well as the effect of co-administration of ineffective doses of fenfluramine and BIMU-8 on Sz behaviors. RESULTS The 5-HT4 antagonist (GR125487) was the only 5-HT receptor antagonist that was able to reverse the action of fenfluramine to block Sz and S-IRA. Treatment with the 5-HT4 receptor agonist (BIMU-8), or co-administration of ineffective doses of BIMU-8 and fenfluramine significantly reduced the incidence of S-IRA and tonic Sz in DBA/1 mice. The antagonists for 5-HT3, 5-HT5A 5-HT6, and 5-HT7 receptors did not significantly affect the action of fenfluramine. However, the 5-HT1A and the 5-HT2 antagonists enhanced the anticonvulsant effects of fenfluramine. CONCLUSIONS These findings suggest that the action of fenfluramine to prevent seizure-induced sudden death in DBA/1 mice is mediated primarily by activation of 5-HT4 receptors. These studies are the first to indicate the therapeutic potential of 5-HT4 receptor agonists either alone or in combination with fenfluramine for preventing SUDEP. Enhancement of the anticonvulsant effect of fenfluramine by 5-HT1A and 5-HT2 antagonists may involve presynaptic actions of these antagonists. Thus, the Sz and S-IRA blocking actions of fenfluramine involve complex interactions with several 5-HT receptor subtypes. These data also provide further support for the serotonin hypothesis of SUDEP.
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Affiliation(s)
- Srinivasan Tupal
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA.
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Martin P, Reeder T, Sourbron J, de Witte PAM, Gammaitoni AR, Galer BS. An Emerging Role for Sigma-1 Receptors in the Treatment of Developmental and Epileptic Encephalopathies. Int J Mol Sci 2021; 22:8416. [PMID: 34445144 PMCID: PMC8395113 DOI: 10.3390/ijms22168416] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 12/14/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are complex conditions characterized primarily by seizures associated with neurodevelopmental and motor deficits. Recent evidence supports sigma-1 receptor modulation in both neuroprotection and antiseizure activity, suggesting that sigma-1 receptors may play a role in the pathogenesis of DEEs, and that targeting this receptor has the potential to positively impact both seizures and non-seizure outcomes in these disorders. Recent studies have demonstrated that the antiseizure medication fenfluramine, a serotonin-releasing drug that also acts as a positive modulator of sigma-1 receptors, reduces seizures and improves everyday executive functions (behavior, emotions, cognition) in patients with Dravet syndrome and Lennox-Gastaut syndrome. Here, we review the evidence for sigma-1 activity in reducing seizure frequency and promoting neuroprotection in the context of DEE pathophysiology and clinical presentation, using fenfluramine as a case example. Challenges and opportunities for future research include developing appropriate models for evaluating sigma-1 receptors in these syndromic epileptic conditions with multisystem involvement and complex clinical presentation.
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Affiliation(s)
- Parthena Martin
- Zogenix, Inc., Emeryville, CA 94608, USA; (P.M.); (T.R.); (A.R.G.)
| | - Thadd Reeder
- Zogenix, Inc., Emeryville, CA 94608, USA; (P.M.); (T.R.); (A.R.G.)
| | - Jo Sourbron
- University Hospital KU Leuven, 3000 Leuven, Belgium;
| | - Peter A. M. de Witte
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences at KU Leuven, 3000 Leuven, Belgium;
| | | | - Bradley S. Galer
- Zogenix, Inc., Emeryville, CA 94608, USA; (P.M.); (T.R.); (A.R.G.)
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15
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Nei M, Pickard A. The role of convulsive seizures in SUDEP. Auton Neurosci 2021; 235:102856. [PMID: 34343824 DOI: 10.1016/j.autneu.2021.102856] [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: 03/17/2021] [Revised: 06/01/2021] [Accepted: 07/19/2021] [Indexed: 11/19/2022]
Abstract
Convulsive seizures are the most consistently reported risk factor for SUDEP. However, the precise mechanisms by which convulsive seizures trigger fatal cardiopulmonary changes are still unclear. Additionally, it is not clear why some seizures cause death when most do not. This article reviews the physiologic changes that occur during and after convulsive seizures and how these may contribute to SUDEP. Seizures activate specific cortical and subcortical regions that can cause potentially lethal cardiorespiratory changes. Clinical factors, including sleep state, medication treatment and withdrawal, positioning and posturing during seizures, and underlying structural or genetic conditions may also affect specific aspects of seizures that may contribute to SUDEP. While seizure control, either through medication or surgical treatment, is the primary intervention that reduces SUDEP risk, unfortunately, seizures cannot be fully controlled despite maximal treatment in a significant proportion of people with epilepsy. Thus specific interventions to prevent adverse seizure-related cardiopulmonary consequences are needed. The potential roles of repositioning/stimulation after seizures, oxygen supplementation, cardiopulmonary resuscitation and clinical treatment options in reducing SUDEP risk are explored. Ultimately, understanding of these factors may lead to interventions that could reduce or prevent SUDEP.
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Affiliation(s)
- Maromi Nei
- Sidney Kimmel Medical College at Thomas Jefferson University, Jefferson Comprehensive Epilepsy Center, Department of Neurology, 901 Walnut Street, Suite 400, Philadelphia, PA 19107, United States of America.
| | - Allyson Pickard
- Sidney Kimmel Medical College at Thomas Jefferson University, Jefferson Comprehensive Epilepsy Center, Department of Neurology, 901 Walnut Street, Suite 400, Philadelphia, PA 19107, United States of America
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16
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Ismayilova K, Hashimova U, Majidi MR, Rustamov F. Effect of fluoxetine on seizures in rats with high susceptibility to audiogenic stress. J Clin Transl Res 2021; 7:277-284. [PMID: 34104832 PMCID: PMC8177837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/24/2021] [Accepted: 03/29/2021] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND The seizures, triggered by a loud sound in laboratory animals, are associated with the imbalance of the brain monoamines. Serotonin (5-HT) is regarded as one of the principal neurotransmitters to be involved in regulation of wide variety of physiological and psychological processes. Among the drugs that affect 5-HT synaptic transmission, the leading role is given to selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine. AIM The aim of the study is to investigate the effects of fluoxetine on seizures in Wistar rats with high susceptibility to audiogenic stress. METHODS The study was performed on male Wistar rats. Before the experiments, the animals were tested for susceptibility to audiogenic seizures by exposure to a sound of 90-110 dB for 2 min in the soundproof box. The difference between congenital susceptibility to seizures served as a basis for dividing animals into two groups: Seizure-susceptible (SS) and seizure-tolerant (ST) rats. One hour before the experiment, the experimental animals were orally administered with fluoxetine, while the control rats were treated with distilled water. The effect of fluoxetine on the level of the biogenic amines in different regions of the brain was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS It has been shown that in 100% of the cases, the control SS rats, exposed to audiogenic stimulus, exhibited wild running around in circles and jumping as some of the signs of seizure responses that evolved into tonic-clonic seizures in 70% of the cases. As regards the experimental SS animals: Only in 60% of the cases (P<0.05), they exhibited wild running and flinch, which did not evolve into the tonic-clonic phase. CONCLUSION Decreased manifestation of seizures in the experimental SS rats under acute administration of fluoxetine may be explained by highly distinctive repertoire and spatial distribution of 5-HT receptors in their brain structures in comparison to the ST rats. RELEVANCE FOR PATIENTS The study of the monoaminergic mechanisms of seizure generation is of practical importance due to the existence of pharmacological agents, which selectively affect the activity of the monoaminergic systems of the brain, as well as the metabolism of the monoamines synthesized by them.
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Affiliation(s)
- Khadija Ismayilova
- Academician Abdulla Garayev Institute of Physiology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan
| | - Ulduz Hashimova
- Academician Abdulla Garayev Institute of Physiology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan
| | - Mohammad Reza Majidi
- Academician Abdulla Garayev Institute of Physiology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan
| | - Farhad Rustamov
- Academician Abdulla Garayev Institute of Physiology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan
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17
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Abstract
PURPOSE OF REVIEW The serotonergic system is implicated in multiple aspects of epilepsy, including seizure susceptibility, sudden unexpected death in epilepsy (SUDEP), and comorbid depression. Despite the complexity of serotonin's effects on various neuronal networks, ongoing research provides considerable insight into the role of serotonin in human epilepsy. This review explores the potential roles of serotonergic therapies to improve clinical outcomes in epilepsy. RECENT FINDINGS In recent decades, research has markedly increased our knowledge of the diverse effects of serotonin on brain function. Animal models of epilepsy have identified the influence of serotonin on seizure threshold in specific brain regions, serotoninergic augmentation's protective effects on terminal apnea and mortality in SUDEP, and mechanisms underlying behavioral improvement in some models of comorbid depression. Human clinical studies are largely consistent with animal data but the translation into definitive treatment decisions has moved less rapidly. SUMMARY Evidence for serotonergic therapy is promising for improvement in seizure control and prevention of SUDEP. For some epilepsies, such as Dravet syndrome, basic research on serotonin receptor agonists has translated into a positive clinical trial for fenfluramine. The cumulative results of safety and efficacy studies support the routine use of SSRIs for comorbid depression in epilepsy.
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Affiliation(s)
| | | | - Matthew S. Gentry
- Department of Molecular and Cellular Biochemistry, University of Kentucky
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18
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Abstract
Sudden unexpected death in epilepsy (SUDEP) remains an important cause of epilepsy-related mortality, especially in patients with refractory epilepsy. The exact cause is not known, but postictal cardiac, respiratory, and brainstem dysfunctions are implicated. SUDEP prevention remains a big challenge. Except for low-quality evidence of preventive effect of nocturnal supervision for SUDEP, no other evidence-based preventive modality is available. Other potential preventive strategies for SUDEP include reducing the occurrence of generalized tonic-clonic seizures using seizure detection devices, detecting cardiorespiratory distress through respiratory and heart rate monitoring devices, preventing airway obstruction (safety pillows), and reducing central hypoventilation using selective serotonin reuptake inhibitors and adenosine and opiate antagonists. However, none of the above-mentioned modalities has been proven to prevent SUDEP. The present review intends to provide insight into the available SUDEP prevention modalities.
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19
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Adhikari Y, Jin X. Intraperitoneal injection of lipopolysaccharide prevents seizure-induced respiratory arrest in a DBA/1 mouse model of SUDEP. Epilepsia Open 2020; 5:386-396. [PMID: 32913947 PMCID: PMC7469803 DOI: 10.1002/epi4.12410] [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] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 03/30/2020] [Accepted: 05/03/2020] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Sudden unexpected death in epilepsy (SUDEP) is the cause of premature death of 50% patients with chronic refractory epilepsy. Respiratory failure during seizures is regarded as an important mechanism of SUDEP. Previous studies have shown that abnormal serotonergic neurotransmission is involved in the pathogenesis of seizure-induced respiratory failure, while enhancing serotonergic neurotransmission in the brainstem suppresses it. Because peripheral inflammation is known to enhance serotonergic neuron activation and 5-HT synthesis and release, we investigated the effect of intraperitoneal lipopolysaccharide (LPS)-induced inflammation on the S-IRA susceptibility during audiogenic seizures in DBA/1 mice. METHODS After DBA/1 mice were primed by exposing to sound stimulation for three consecutive days, they were tested for seizure severity and seizure-induced respiratory arrest (S-IRA) induced by sound stimulation under different conditions. We determined the dose and time course of the effects of intraperitoneal administration of LPS on audiogenic seizures and S-IRA. The effects of blocking TLR4 or RAGE receptors and blocking 5-HT receptors on the LPS-induced effect on S-IRA were investigated. Statistical significance was evaluated using the Kruskal-Wallis test. RESULTS Intraperitoneal injection of LPS significantly had dose-dependent effects in reducing the incidence of S-IRA as well as seizure severity in DBA/1 mice. The protective effect of LPS on S-IRA peaked at 8-12 hours after LPS injection and was related to both reducing seizure severity and enhancing autoresuscitation. Blocking TLR4 or RAGE receptor with TAK-242 or FPS-ZM1, respectively, prior to LPS injection attenuated its effects on S-IRA and seizure severity. Injection of a nonselective 5-HT receptor antagonist, cyproheptadine, or a 5-HT3 receptor antagonist, ondansetron, was effective in blocking LPS-induced effect on S-IRA. Immunostaining results showed a significant increase in c-Fos-positive serotonergic neurons in the dorsal raphe. SIGNIFICANCE This is the first study that demonstrates the effect of intraperitoneal LPS injection-induced inflammation on reducing S-IRA susceptibility and provides additional evidence supporting the serotonin hypothesis on SUDEP. Our study suggests that inflammation may enhance brainstem 5-HT neurotransmission to promote autoresuscitation during seizure and prevent SUDEP.
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Affiliation(s)
- Yadav Adhikari
- Spinal Cord and Brain Injury Research GroupStark Neurosciences Research Institute. Indiana University School of MedicineIndianapolisIndianaUSA
| | - Xiaoming Jin
- Department of Anatomy, Cell Biology and PhysiologyStark Neurosciences Research InstituteIndiana University School of MedicineIndianapolisIndianaUSA
- Department of Neurological SurgeryStark Neurosciences Research InstituteIndiana University School of MedicineIndianapolisIndianaUSA
- Spinal Cord and Brain Injury Research GroupStark Neurosciences Research Institute. Indiana University School of MedicineIndianapolisIndianaUSA
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20
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Löscher W, Klein P. The feast and famine: Epilepsy treatment and treatment gaps in early 21st century. Neuropharmacology 2020; 170:108055. [PMID: 32199986 DOI: 10.1016/j.neuropharm.2020.108055] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
| | - Pavel Klein
- Mid-Atlantic Epilepsy and Sleep Center, Bethesda, MD, USA
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21
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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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22
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Martin B, Dieuset G, Pawluski JL, Costet N, Biraben A. Audiogenic seizure as a model of sudden death in epilepsy: A comparative study between four inbred mouse strains from early life to adulthood. Epilepsia 2020; 61:342-349. [PMID: 31981213 DOI: 10.1111/epi.16432] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 12/26/2019] [Accepted: 12/30/2019] [Indexed: 01/31/2023]
Abstract
OBJECTIVE Mouse models of sudden unexpected death in epileptic patients (SUDEP) using audiogenic seizures (AGS) are valuable because death can occur following a sound-induced seizure in the absence of any pharmacologic or electric component. However, only a few strains of mice are AGS prone, and the vast majority of studies involve DBA/2 or DBA/1 inbred strains. With the goal of characterizing the variation of AGS susceptibility with age, and of offering a larger panel of mice available for AGS studies, we performed a comparative study of the variability in AGS responses. METHODS The variation of AGS with age was determined in two classically used inbred strains of mice, DBA/2 and DBA/1, and two additional strains, BALB/c and 129/SvTer. As AGS-stimulated tonic seizures can be lethal or nonlethal, even in the same inbred strain, in a second experiment, we addressed whether there is an innate capacity to reproduce the same response after a tonic AGS, referred to as "determinism," in the DBA/2J, DBA/1J, and 129/SvTer mouse strains. RESULTS Results show that the 129/SvTer mouse is a more versatile model of SUDEP due to its wider age range of susceptibility compared to the DBA/2J and DBA/1J mouse strains. In addition, we show that determinism is not consistently evident in DBA/2J and 129/SvTer strains after AGS. Hence, one cannot be certain that a lethal AGS will always be lethal in successive testing after resuscitation and vice versa in these two mouse strains. SIGNIFICANCE These studies highlight the phenotypic variability of AGS in different mouse strains, show the value of an additional mouse strain, 129/SvTer, for studies using AGS, and thus provide valuable information for future studies of AGS and SUDEP.
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Affiliation(s)
- Benoît Martin
- Univ Rennes, CHU Rennes, Inserm, LTSI (Laboratoire de Traitement du Signal et de l'Image), UMR-1099, F-35000, Rennes, France
| | - Gabriel Dieuset
- Univ Rennes, CHU Rennes, Inserm, LTSI (Laboratoire de Traitement du Signal et de l'Image), UMR-1099, F-35000, Rennes, France
| | - Jodi L Pawluski
- Univ Rennes, CHU Rennes, Inserm, LTSI (Laboratoire de Traitement du Signal et de l'Image), UMR-1099, F-35000, Rennes, France
| | - Nathalie Costet
- Univ Rennes, CHU Rennes, Inserm, LTSI (Laboratoire de Traitement du Signal et de l'Image), UMR-1099, F-35000, Rennes, France.,Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail), UMR_S 1085, F-35000, Rennes, France
| | - Arnaud Biraben
- Univ Rennes, CHU Rennes, Inserm, LTSI (Laboratoire de Traitement du Signal et de l'Image), UMR-1099, F-35000, Rennes, France
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23
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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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24
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Murugesan A, Rani MRS, Vilella L, Lacuey N, Hampson JP, Faingold CL, Friedman D, Devinsky O, Sainju RK, Schuele S, Diehl B, Nei M, Harper RM, Bateman LM, Richerson G, Lhatoo SD. Postictal serotonin levels are associated with peri-ictal apnea. Neurology 2019; 93:e1485-e1494. [PMID: 31484709 DOI: 10.1212/wnl.0000000000008244] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 05/15/2019] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE To determine the relationship between serum serotonin (5-HT) levels, ictal central apnea (ICA), and postconvulsive central apnea (PCCA) in epileptic seizures. METHODS We prospectively evaluated video EEG, plethysmography, capillary oxygen saturation (SpO2), and ECG for 49 patients (49 seizures) enrolled in a multicenter study of sudden unexpected death in epilepsy (SUDEP). Postictal and interictal venous blood samples were collected after a clinical seizure for measurement of serum 5-HT levels. Seizures were classified according to the International League Against Epilepsy 2017 seizure classification. We analyzed seizures with and without ICA (n = 49) and generalized convulsive seizures (GCS) with and without PCCA (n = 27). RESULTS Postictal serum 5-HT levels were increased over interictal levels for seizures without ICA (p = 0.01), compared to seizures with ICA (p = 0.21). In patients with GCS without PCCA, serum 5-HT levels were increased postictally compared to interictal levels (p < 0.001), but not in patients with seizures with PCCA (p = 0.22). Postictal minus interictal 5-HT levels also differed between the 2 groups with and without PCCA (p = 0.03). Increased heart rate was accompanied by increased serum 5-HT levels (postictal minus interictal) after seizures without PCCA (p = 0.03) compared to those with PCCA (p = 0.42). CONCLUSIONS The data suggest that significant seizure-related increases in serum 5-HT levels are associated with a lower incidence of seizure-related breathing dysfunction, and may reflect physiologic changes that confer a protective effect against deleterious phenomena leading to SUDEP. These results need to be confirmed with a larger sample size study.
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Affiliation(s)
- Arun Murugesan
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - M R Sandhya Rani
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD.
| | - Laura Vilella
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Nuria Lacuey
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Johnson P Hampson
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Carl L Faingold
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Daniel Friedman
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Orrin Devinsky
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Rup K Sainju
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Stephan Schuele
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Beate Diehl
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Maromi Nei
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Ronald M Harper
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Lisa M Bateman
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - George Richerson
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
| | - Samden D Lhatoo
- From the Department of Neurology (A.M.), Case Western Reserve University; Department of Neurology (M.R.S.R., L.V., N.L., J.P.H., S.D.L.), McGovern Medical School, University of Texas Health Science Center at Houston; Department of Pharmacology and Neurology (C.L.F.), Southern Illinois University School of Medicine, Springfield; Department of Neurology (D.F., O.D.), New York University School of Medicine, New York; Department of Neurology (R.K.S., G.R.), University of Iowa Carver College of Medicine, Iowa City; Department of Neurology (S.S.), Northwestern University Feinberg School of Medicine, Chicago, IL; Institute of Neurology (B.D.), University College London, UK; Department of Neurology (M.N.), Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; Department of Neurobiology (R.M.H.), David Geffen School of Medicine at UCLA, Los Angeles, CA; Department of Neurology (L.M.B.), Columbia University Medical Center, New York, NY; and Center for SUDEP Research (M.R.S.R., L.V., N.L., D.F., O.D., R.K.S., S.S., B.D., M.N., R.M.H., L.M.B., G.R., S.D.L.), National Institute for Neurological Disorders and Stroke, Bethesda, MD
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25
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Lacuey N, Martins R, Vilella L, Hampson JP, Rani MRS, Strohl K, Zaremba A, Hampson JS, Sainju RK, Friedman D, Nei M, Scott C, Gehlbach BK, Hupp NJ, Schuele S, Ogren J, Harper RM, Allen L, Diehl B, Bateman LM, Devinsky O, Richerson GB, Lhatoo S. The association of serotonin reuptake inhibitors and benzodiazepines with ictal central apnea. Epilepsy Behav 2019; 98:73-79. [PMID: 31301453 PMCID: PMC8975169 DOI: 10.1016/j.yebeh.2019.06.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/14/2019] [Accepted: 06/15/2019] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Ictal (ICA) and postconvulsive central apnea (PCCA) have been implicated in sudden unexpected death in epilepsy (SUDEP) pathomechanisms. Previous studies suggest that serotonin reuptake inhibitors (SRIs) and benzodiazepines (BZDs) may influence breathing. The aim of this study was to investigate if chronic use of these drugs alters central apnea occurrence in patients with epilepsy. METHODS Patients with epilepsy admitted to epilepsy monitoring units (EMUs) in nine centers participating in a SUDEP study were consented. Polygraphic physiological parameters were analyzed, including video-electroencephalography (VEEG), thoracoabdominal excursions, and pulse oximetry. Outpatient medication details were collected. Patients and seizures were divided into SRI, BZD, and control (no SRI or BZD) groups. Ictal central apnea and PCCA, hypoxemia, and electroclinical features were assessed for each group. RESULTS Four hundred and seventy-six seizures were analyzed (204 patients). The relative risk (RR) for ICA in the SRI group was half that of the control group (p = 0.02). In the BZD group, ICA duration was significantly shorter than in the control group (p = 0.02), as was postictal generalized EEG suppression (PGES) duration (p = 0.021). Both SRI and BZD groups were associated with smaller seizure-associated oxygen desaturation (p = 0.009; p ≪ 0.001). Neither presence nor duration of PCCA was significantly associated with SRI or BZD (p ≫ 0.05). CONCLUSIONS Seizures in patients taking SRIs have lower occurrence of ICA, and patients on chronic treatment with BZDs have shorter ICA and PGES durations. Preventing or shortening ICA duration by using SRIs and/or BZD in patients with epilepsy may play a possible role in SUDEP risk reduction.
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Affiliation(s)
- Nuria Lacuey
- Epilepsy Center, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
| | - Rita Martins
- Hospital Prof. Doutor Fernando Fonseca, Amadora, Portugal
| | - Laura Vilella
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA
| | - Johnson P. Hampson
- Epilepsy Center, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | | | - Kingman Strohl
- Division of Pulmonary, Critical Care and Sleep Medicine, University Hospitals Medical Center, Cleveland, OH, USA
| | - Anita Zaremba
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA
| | | | - Rup K. Sainju
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Daniel Friedman
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,NYU Langone School of Medicine, New York, NY, USA
| | - Maromi Nei
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Catherine Scott
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,Institute of Neurology, University College London, London, UK
| | - Brian K Gehlbach
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Norma J. Hupp
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA
| | - Stephan Schuele
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,Northwestern University, Feinberg School of Medicine, Chicago
| | - Jennifer Ogren
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,Department of Neurobiology and the Brain Research Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Ronald M. Harper
- Hospital Prof. Doutor Fernando Fonseca, Amadora, Portugal,Department of Neurobiology and the Brain Research Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
| | - Luke Allen
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,Institute of Neurology, University College London, London, UK
| | - Beate Diehl
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,Institute of Neurology, University College London, London, UK
| | - Lisa M. Bateman
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,Department of Neurology, Columbia University, New York, NY, USA
| | - Orrin Devinsky
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,NYU Langone School of Medicine, New York, NY, USA
| | - George B. Richerson
- NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA,University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Samden Lhatoo
- Epilepsy Center, University Hospitals Cleveland Medical Center, Cleveland, OH, USA,NINDS Center for SUDEP Research (CSR), Cleveland, OH, USA
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26
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Patodia S, Somani A, O'Hare M, Venkateswaran R, Liu J, Michalak Z, Ellis M, Scheffer IE, Diehl B, Sisodiya SM, Thom M. The ventrolateral medulla and medullary raphe in sudden unexpected death in epilepsy. Brain 2019; 141:1719-1733. [PMID: 29608654 PMCID: PMC5972615 DOI: 10.1093/brain/awy078] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/01/2018] [Indexed: 11/14/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a leading cause of premature death in patients with epilepsy. One hypothesis proposes that sudden death is mediated by post-ictal central respiratory depression, which could relate to underlying pathology in key respiratory nuclei and/or their neuromodulators. Our aim was to investigate neuronal populations in the ventrolateral medulla (which includes the putative human pre-Bötzinger complex) and the medullary raphe. Forty brainstems were studied comprising four groups: 14 SUDEP, six epilepsy controls, seven Dravet syndrome cases and 13 non-epilepsy controls. Serial sections through the medulla (from obex 1 to 10 mm) were stained for Nissl, somatostatin, neurokinin 1 receptor (for pre-Bötzinger complex neurons) and galanin, tryptophan hydroxylase and serotonin transporter (neuromodulatory systems). Using stereology total neuronal number and densities, with respect to obex level, were measured. Whole slide scanning image analysis was used to quantify immunolabelling indices as well as co-localization between markers. Significant findings included reduction in somatostatin neurons and neurokinin 1 receptor labelling in the ventrolateral medulla in sudden death in epilepsy compared to controls (P < 0.05). Galanin and tryptophan hydroxylase labelling was also reduced in sudden death cases and more significantly in the ventrolateral medulla region than the raphe (P < 0.005 and P < 0.05). With serotonin transporter, reduction in labelling in cases of sudden death in epilepsy was noted only in the raphe (P ≤ 0.01); however, co-localization with tryptophan hydroxylase was significantly reduced in the ventrolateral medulla. Epilepsy controls and cases with Dravet syndrome showed less significant alterations with differences from non-epilepsy controls noted only for somatostatin in the ventrolateral medulla (P < 0.05). Variations in labelling with respect to obex level were noted of potential relevance to the rostro-caudal organization of respiratory nuclear groups, including tryptophan hydroxylase, where the greatest statistical difference noted between all epilepsy cases and controls was at obex 9-10 mm (P = 0.034), the putative level of the pre-Bötzinger complex. Furthermore, there was evidence for variation with duration of epilepsy for somatostatin and neurokinin 1 receptor. Our findings suggest alteration to neuronal populations in the medulla in SUDEP with evidence for greater reduction in neuromodulatory neuropeptidergic and mono-aminergic systems, including for galanin, and serotonin. Other nuclei need to be investigated to evaluate if this is part of more widespread brainstem pathology. Our findings could be a result of previous seizures and may represent a pathological risk factor for SUDEP through impaired respiratory homeostasis during a seizure.
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Affiliation(s)
- Smriti Patodia
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Alyma Somani
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Megan O'Hare
- Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Ranjana Venkateswaran
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Joan Liu
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Department of Biomedical Sciences, University of Westminster London W1W 6UW, UK
| | - Zuzanna Michalak
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Matthew Ellis
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine (Neurology), University of Melbourne, Victoria 3052, Australia
| | - Beate Diehl
- Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Sanjay M Sisodiya
- Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Maria Thom
- Departments of Neuropathology, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Clinical and Experimental Epilepsy and Chalfont Centre for Epilepsy, UCL, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Somboon T, Grigg-Damberger MM, Foldvary-Schaefer N. Epilepsy and Sleep-Related Breathing Disturbances. Chest 2019; 156:172-181. [DOI: 10.1016/j.chest.2019.01.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 01/12/2019] [Accepted: 01/16/2019] [Indexed: 12/18/2022] Open
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Buchanan GF. Impaired CO 2-Induced Arousal in SIDS and SUDEP. Trends Neurosci 2019; 42:242-250. [PMID: 30905388 DOI: 10.1016/j.tins.2019.02.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/21/2019] [Accepted: 02/06/2019] [Indexed: 12/24/2022]
Abstract
Premature, sudden death is devastating. Certain patient populations are at greater risk to succumb to sudden death. For instance, infants under 1year of age are at risk for sudden infant death syndrome (SIDS), and patients with epilepsy are at risk for sudden unexpected death in epilepsy (SUDEP). Deaths are attributed to these syndromic entities in these select populations when other diagnoses have been excluded. There are a number of similarities between these syndromes, and the commonalities suggest that the two syndromes may share certain etiological features. One such feature may be deficiency of arousal to CO2. Under normal conditions, CO2 is a potent arousal stimulus. Circumstances surrounding SIDS and SUDEP deaths often facilitate CO2 elevation, and faulty CO2 arousal mechanisms could, at least in part, contribute to death.
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Affiliation(s)
- Gordon F Buchanan
- Department of Neurology and Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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29
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Kommajosyula SP, Faingold CL. Neural activity in the periaqueductal gray and other specific subcortical structures is enhanced when a selective serotonin reuptake inhibitor selectively prevents seizure-induced sudden death in the DBA/1 mouse model of sudden unexpected death in epilepsy. Epilepsia 2019; 60:1221-1233. [PMID: 31056750 DOI: 10.1111/epi.14759] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Sudden unexpected death in epilepsy (SUDEP) is a critical issue in epilepsy, and DBA/1 mice are a useful animal model of this devastating epilepsy sequela. The serotonin hypothesis for SUDEP proposes that modifying serotonergic function significantly alters susceptibility to seizure-induced respiratory arrest (S-IRA). Agents that enhance serotonergic function, including a selective serotonin reuptake inhibitor, fluoxetine, selectively prevent S-IRA in DBA/1 mice. This study examined fluoxetine-induced changes in brain activity using manganese-enhanced magnetic resonance imaging (MEMRI) to reveal sites in the DBA/1 mouse brain where fluoxetine acts to prevent S-IRA. METHODS DBA/1 mice were subjected to audiogenic seizures (Sz) after saline or fluoxetine (45 mg/kg, intraperitoneal) administration. Control DBA/1 mice received fluoxetine or saline, but Sz were not evoked. A previous MEMRI study established the regions of interest (ROIs) for Sz in the DBA/1 mouse brain, and the present study examined MEMRI differences in the ROIs of these mouse groups. RESULTS The neural activity in several ROIs was significantly increased in fluoxetine-treated DBA/1 mice that exhibited Sz but not S-IRA when compared to the saline-treated mice that exhibited both Sz and respiratory arrest. These structures included the periaqueductal gray (PAG), amygdala, reticular formation (sensorimotor-limbic network), Kölliker-Fuse nucleus, facial-parafacial group (respiratory network), and pontine raphe. Of these ROIs, only the PAG showed significantly decreased neural activity with saline pretreatment when seizure-induced respiratory arrest occurred as compared to saline treatment without seizure. SIGNIFICANCE The PAG is known to play an important compensatory role for respiratory distress caused by numerous exigent situations in normal animals. The pattern of fluoxetine-induced activity changes in the present study suggests that PAG may be the most critical target for fluoxetine's action to prevent seizure-induced sudden death. These findings have potential clinical importance, because there is evidence of anomalous serotonergic function and PAG imaging abnormalities in human SUDEP.
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Affiliation(s)
- Srinivasa P Kommajosyula
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois
| | - Carl L Faingold
- Departments of Pharmacology and Neurology, Southern Illinois University School of Medicine, Springfield, Illinois
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Tupal S, Faingold CL. Fenfluramine, a serotonin-releasing drug, prevents seizure-induced respiratory arrest and is anticonvulsant in the DBA/1 mouse model of SUDEP. Epilepsia 2019; 60:485-494. [PMID: 30719703 DOI: 10.1111/epi.14658] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 01/02/2019] [Accepted: 01/07/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Prevention of sudden unexpected death in epilepsy (SUDEP) is a critical goal for epilepsy therapy. The DBA/1 mouse model of SUDEP exhibits an elevated susceptibility to seizure-induced death in response to electroconvulsive shock, hyperthermia, convulsant drug, and acoustic stimulation. The serotonin hypothesis of SUDEP is based on findings that treatments which modify serotonergic function significantly alter susceptibility to seizure-induced sudden death in several epilepsy models, including DBA/1 mice. Serotonergic abnormalities have also recently been observed in human SUDEP. Fenfluramine is a drug that enhances serotonin release in the brain. Recent studies have found that the addition of fenfluramine improved seizure control in patients with Dravet syndrome, which has a high incidence of SUDEP. Therefore, we investigated the effects of fenfluramine on seizures and seizure-induced respiratory arrest (S-IRA) in DBA/1 mice. METHODS The dose and time course of the effects of fenfluramine (i.p.) on audiogenic seizures (Sz) induced by an electric bell in DBA/1 mice were determined. Videos of Sz-induced behaviors were recorded for analysis. Statistical significance (P < 0.05) was evaluated using the chi-square test. RESULTS Sixteen hours after administration of 15 mg/kg of fenfluramine, a high incidence of selective block of S-IRA susceptibility (P < 0.001) occurred in DBA/1 mice without blocking any convulsive behavior. Thirty minutes after 20-40 mg/kg of fenfluramine, significant reductions of seizure incidence and severity, as well as S-IRA susceptibility occurred, which were long-lasting (≥48 hours). The median effective dose (ED50 ) of fenfluramine for significantly reducing Sz at 30 minutes was 21 mg/kg. SIGNIFICANCE This study presents the first evidence for the effectiveness of fenfluramine in reducing seizure incidence, severity, and S-IRA susceptibility in a mammalian SUDEP model. The ability of fenfluramine to block S-IRA selectively suggests the potential usefulness of fenfluramine in prophylaxis of SUDEP. These results further confirm and extend the serotonin hypothesis of SUDEP.
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Affiliation(s)
- Srinivasan Tupal
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois
| | - Carl L Faingold
- Departments of Pharmacology and Neurology, Southern Illinois University School of Medicine, Springfield, Illinois
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Kommajosyula SP, Tupal S, Faingold CL. Deficient post-ictal cardiorespiratory compensatory mechanisms mediated by the periaqueductal gray may lead to death in a mouse model of SUDEP. Epilepsy Res 2018; 147:1-8. [PMID: 30165263 DOI: 10.1016/j.eplepsyres.2018.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/20/2018] [Accepted: 08/18/2018] [Indexed: 11/17/2022]
Abstract
Post-ictal cardiorespiratory failure is implicated as a major cause of sudden unexpected death in epilepsy (SUDEP) in patients. The DBA/1 mouse model of SUDEP is abnormally susceptible to fatal seizure-induced cardiorespiratory failure (S-CRF) induced by convulsant drug, hyperthermia, electroshock, and acoustic stimulation. Clinical and pre-clinical studies have implicated periaqueductal gray (PAG) abnormalities in SUDEP. Recent functional neuroimaging studies observed that S-CRF resulted in selective changes in PAG neuronal activity in DBA/1 mice. The PAG plays a critical compensatory role for respiratory distress caused by numerous physiological challenges in non-epileptic individuals. These observations suggest that abnormalities in PAG-mediated cardiorespiratory modulation may contribute to S-CRF in DBA/1 mice. To evaluate this, electrical stimulation (20 Hz, 20-100 μA, 10 s) was presented in the PAG of anesthetized DBA/1 and C57BL/6 (non-epileptic) control mice, and post-stimulus changes in respiration [inter-breath interval (IBI)] and heart rate variability (HRV) were examined. The post-stimulus period was considered analogous to the post-ictal period when S-CRF occurred in previous DBA/1 mouse studies. PAG stimulation caused significant intensity-related decreases in IBI in both mouse strains. However, this effect was significantly reduced in DBA/1 vis-a-vis C57BL/6 mice. These changes began immediately following cessation of stimulation and remained significant for 10 s. This time period is critical for initiating resuscitation to successfully prevent seizure-induced death in previous DBA/1 mouse experiments. Significant post-stimulus increases in HRV were also seen at ≥60 μA in the PAG in C57BL/6 mice, which were absent in DBA/1 mice. These data along with previous neuroimaging findings suggest that compensatory cardiorespiratory modulation mediated by PAG is deficient, which may be important to the susceptibility of DBA/1 mice to S-CRF. These observations suggest that correcting this deficit pharmacologically or by electrical stimulation may help to prevent S-CRF. These findings further support the potential importance of PAG abnormalities to human SUDEP.
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Affiliation(s)
- Srinivasa P Kommajosyula
- Departments of Pharmacology and Neurology, Southern Illinois University School of Medicine, PO BOX 19629, Springfield, IL, 62794-9629, United States
| | - Srinivasan Tupal
- Departments of Pharmacology and Neurology, Southern Illinois University School of Medicine, PO BOX 19629, Springfield, IL, 62794-9629, United States
| | - Carl L Faingold
- Departments of Pharmacology and Neurology, Southern Illinois University School of Medicine, PO BOX 19629, Springfield, IL, 62794-9629, United States.
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Zhang H, Zhao H, Zeng C, Van Dort C, Faingold CL, Taylor NE, Solt K, Feng HJ. Optogenetic activation of 5-HT neurons in the dorsal raphe suppresses seizure-induced respiratory arrest and produces anticonvulsant effect in the DBA/1 mouse SUDEP model. Neurobiol Dis 2018; 110:47-58. [PMID: 29141182 PMCID: PMC5748009 DOI: 10.1016/j.nbd.2017.11.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/29/2017] [Accepted: 11/11/2017] [Indexed: 01/02/2023] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a devastating epilepsy complication. Seizure-induced respiratory arrest (S-IRA) occurs in many witnessed SUDEP patients and animal models as an initiating event leading to death. Thus, understanding the mechanisms underlying S-IRA will advance the development of preventive strategies against SUDEP. Serotonin (5-HT) is an important modulator for many vital functions, including respiration and arousal, and a deficiency of 5-HT signaling is strongly implicated in S-IRA in animal models, including the DBA/1 mouse. However, the brain structures that contribute to S-IRA remain elusive. We hypothesized that the dorsal raphe (DR), which sends 5-HT projections to the forebrain, is implicated in S-IRA. The present study used optogenetics in the DBA/1 mouse model of SUDEP to selectively activate 5-HT neurons in the DR. Photostimulation of DR 5-HT neurons significantly and reversibly reduced the incidence of S-IRA evoked by acoustic stimulation. Activation of 5-HT neurons in the DR suppressed tonic seizures in most DBA/1 mice without altering the seizure latency and duration of wild running and clonic seizures evoked by acoustic stimulation. This suppressant effect of photostimulation on S-IRA is independent of seizure models, as optogenetic stimulation of DR also reduced S-IRA induced by pentylenetetrazole, a proconvulsant widely used to model human generalized seizures. The S-IRA-suppressing effect of photostimulation was increased by 5-hydroxytryptophan, a chemical precursor for 5-HT synthesis, and was reversed by ondansetron, a specific 5-HT3 receptor antagonist, indicating that reduction of S-IRA by photostimulation of the DR is specifically mediated by enhanced 5-HT neurotransmission. Our findings suggest that deficits in 5-HT neurotransmission in the DR are implicated in S-IRA in DBA/1 mice, and that targeted intervention in the DR is potentially useful for prevention of SUDEP.
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Affiliation(s)
- Honghai Zhang
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA; Department of Anesthesia, Hangzhou First People's Hospital, Nanjing Medical University, Hangzhou 310006, China
| | - Haiting Zhao
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA; Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Chang Zeng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA; Health Management Center, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Christa Van Dort
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA; Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
| | - Carl L Faingold
- Department of Pharmacology and Neurology, Division of Neurosurgery, Southern Illinois University School of Medicine, Springfield, IL 62794, USA
| | - Norman E Taylor
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA
| | - Ken Solt
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA.
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The effect of atomoxetine, a selective norepinephrine reuptake inhibitor, on respiratory arrest and cardiorespiratory function in the DBA/1 mouse model of SUDEP. Epilepsy Res 2017; 137:139-144. [PMID: 28844345 DOI: 10.1016/j.eplepsyres.2017.08.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 06/22/2017] [Accepted: 08/12/2017] [Indexed: 11/20/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a significant public health burden. The mechanisms of SUDEP are elusive, although cardiorespiratory dysfunction is a likely contributor. Clinical and animal studies indicate that seizure-induced respiratory arrest (S-IRA) is the primary event leading to death in many SUDEP cases. Our prior studies demonstrated that intraperitoneal (IP) injection of atomoxetine, a norepinephrine reuptake inhibitor (NRI) widely used to treat attention deficit hyperactivity disorder, suppresses S-IRA in DBA/1 mice. In the current study, we injected atomoxetine intracerebroventricularly (ICV) and measured its effect on S-IRA in DBA/1 mice to determine its central effects. Additionally, to test our hypothesis that atomoxetine reduces S-IRA via altering cardiorespiratory function, we examined the effect of atomoxetine on respiratory and cardiac function using non-invasive plethysmography and ECG in anesthetized DBA/1 mice, and on blood pressure and heart rate using a tail-cuff system in conscious DBA/1 mice. ICV administration of atomoxetine at 200-250nmol significantly reduced S-IRA evoked by acoustic stimulation in DBA/1 mice, consistent with a central atomoxetine effect on S-IRA. Peripheral atomoxetine administration at a dosage that reduces S-IRA (15mg/kg, IP) slightly increased basal ventilation and the ventilatory response to 7% CO2, but exerted no effect on heart rate in anesthetized DBA/1 mice. IP injection of atomoxetine produced no effect on the heart rate and blood pressures in conscious mice. These data suggest that atomoxetine suppresses S-IRA through direct effects on the CNS and potentially through enhanced lung ventilation in DBA/1 mice.
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Zhang H, Zhao H, Feng HJ. Atomoxetine, a norepinephrine reuptake inhibitor, reduces seizure-induced respiratory arrest. Epilepsy Behav 2017; 73:6-9. [PMID: 28605634 PMCID: PMC5545072 DOI: 10.1016/j.yebeh.2017.04.046] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 04/26/2017] [Accepted: 04/26/2017] [Indexed: 12/31/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a devastating epilepsy complication, and no effective preventive strategies are currently available for this fatal disorder. Clinical and animal studies of SUDEP demonstrate that seizure-induced respiratory arrest (S-IRA) is the primary event leading to death after generalized seizures in many cases. Enhancing brain levels of serotonin reduces S-IRA in animal models relevant to SUDEP, including the DBA/1 mouse. Given that serotonin in the brain plays an important role in modulating respiration and arousal, these findings suggest that deficits in respiration and/or arousal may contribute to S-IRA. It is well known that norepinephrine is an important neurotransmitter that modulates respiration and arousal in the brain as well. Therefore, we hypothesized that enhancing noradrenergic neurotransmission suppresses S-IRA. To test this hypothesis, we examined the effect of atomoxetine, a norepinephrine reuptake inhibitor (NRI), on S-IRA evoked by either acoustic stimulation or pentylenetetrazole in DBA/1 mice. We report the original observation that atomoxetine specifically suppresses S-IRA without altering the susceptibility to seizures evoked by acoustic stimulation, and atomoxetine also reduces S-IRA evoked by pentylenetetrazole in DBA/1 mice. Our data suggest that the noradrenergic signaling is importantly involved in S-IRA, and that atomoxetine, a medication widely used to treat attention deficit hyperactivity disorder (ADHD), is potentially useful to prevent SUDEP.
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Affiliation(s)
- Honghai Zhang
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA,Department of Anesthesia, Hangzhou First People's Hospital, Nanjing Medical University, Hangzhou, China
| | - Haiting Zhao
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA,Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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Kommajosyula SP, Randall ME, Brozoski TJ, Odintsov BM, Faingold CL. Specific subcortical structures are activated during seizure-induced death in a model of sudden unexpected death in epilepsy (SUDEP): A manganese-enhanced magnetic resonance imaging study. Epilepsy Res 2017. [PMID: 28646692 DOI: 10.1016/j.eplepsyres.2017.05.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a major concern for patients with epilepsy. In most witnessed cases of SUDEP generalized seizures and respiratory failure preceded death, and pre-mortem neuroimaging studies in SUDEP patients observed changes in specific subcortical structures. Our study examined the role of subcortical structures in the DBA/1 mouse model of SUDEP using manganese-enhanced magnetic resonance imaging (MEMRI). These mice exhibit acoustically-evoked generalized seizures leading to seizure-induced respiratory arrest (S-IRA) that results in sudden death unless resuscitation is rapidly instituted. MEMRI data in the DBA/1 mouse brain immediately after acoustically-induced S-IRA were compared to data in C57 (control) mice that were exposed to the same acoustic stimulus that did not trigger seizures. The animals were anesthetized and decapitated immediately after seizure in DBA/1 mice and after an equivalent time in control mice. Comparative T1 weighted MEMRI images were evaluated using a 14T MRI scanner and quantified. We observed significant increases in activity in DBA/1 mice as compared to controls at previously-implicated auditory (superior olivary complex) and sensorimotor-limbic [periaqueductal gray (PAG) and amygdala] networks and also in structures in the respiratory network. The activity at certain raphe nuclei was also increased, suggesting activation of serotonergic mechanisms. These data are consistent with previous findings that enhancing the action of serotonin prevents S-IRA in this SUDEP model. Increased activity in the PAG and the respiratory and raphe nuclei suggest that compensatory mechanisms for apnea may have been activated by S-IRA, but they were not sufficient to prevent death. The present findings indicate that changes induced by S-IRA in specific subcortical structures in DBA/1 mice are consistent with human SUDEP findings. Understanding the changes in brain activity during seizure-induced death in animals may lead to improved approaches directed at prevention of human SUDEP.
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Affiliation(s)
- Srinivasa P Kommajosyula
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, United States
| | - Marcus E Randall
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, United States
| | - Thomas J Brozoski
- Department of Surgery/Otolaryngology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, United States
| | - Boris M Odintsov
- Beckman Institute, University of Illinois Urbana-Champaign, 405 N. Mathews Ave., Urbana, IL, United States
| | - Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, United States.
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Abstract
This paper reviews advances in epilepsy in recent years with an emphasis on therapeutics and underlying mechanisms, including status epilepticus, drug and surgical treatments. Lessons from rarer epilepsies regarding the relationship between epilepsy type, mechanisms and choice of antiepileptic drugs (AED) are explored and data regarding AED use in pregnancy are reviewed. Concepts evolving towards a move from treating seizures to treating epilepsy are discussed, both in terms of the mechanisms of epileptogenesis, and in terms of epilepsy's broader comorbidity, especially depression.
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