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Chan SW, Chun A, Nguyen L, Bubolz B, Anderson AE, Lai YC. Associations between epilepsy, respiratory impairment, and minor ECG abnormalities in children. Seizure 2024; 122:39-44. [PMID: 39326248 DOI: 10.1016/j.seizure.2024.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 09/06/2024] [Accepted: 09/17/2024] [Indexed: 09/28/2024] Open
Abstract
OBJECTIVE We sought to examine the effects of acute seizures and respiratory derangement on the cardiac electrical properties reflected on the electrocardiogram (ECG); and to analyze their potential interactions with a diagnosis of epilepsy in children. METHODS Emergency center (EC) visits with seizure or epilepsy diagnostic codes from 1/2011-12/2013 were included if they had ECG within 24 h of EC visit. Patients were excluded if they had pre-existing cardiac conditions, ion channelopathy, or were taking specific cardiac medications. Control subjects were 1:1 age and gender matched. Abnormal ECG was defined as changes in rhythm, PR, QRS, or corrected QT intervals; QRS axis or morphology; ST segment; or T wave morphology from normal standards. We identified independent associations between clinical factors and abnormal ECG findings using multivariable logistic regression modeling. RESULTS Ninety-five children with epilepsy presented to the EC with seizures, respiratory distress, and other concerns. Three hundred children without epilepsy presented with seizures. There was an increased prevalence of minor ECG abnormalities in children with epilepsy (49 %) compared to the control subjects (29 %) and those without epilepsy (36 %). Epilepsy (OR: 1.61, 95 %CI: 1.01-2.6), need for supplemental oxygen (OR 3.06, 95 % CI: 1.45-6.44) or mechanical ventilation (OR: 2.5, 95 % CI: 1.03-6.05) were independently associated with minor ECG abnormalities. Secondary analyses further demonstrated an independent association between level of respiratory support and ECG abnormalities only in the epilepsy group. SIGNIFICANCE Independent association of increased respiratory support with minor ECG abnormalities suggests a potential respiratory influence on the hearts of children with epilepsy.
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Affiliation(s)
- See Wai Chan
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Angela Chun
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Pediatric Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Linh Nguyen
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Emergency Medicine, Orlando Health, Orlando, FL, USA
| | - Beth Bubolz
- Division of Pediatric Emergency Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Pediatric Emergency Medicine, The Ohio State University School of Medicine, Columbus, OH, USA
| | - Anne E Anderson
- Division of Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Yi-Chen Lai
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
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Iyer SH, Hinman JE, Warren T, Matthews SA, Simeone TA, Simeone KA. Altered ventilatory responses to hypercapnia-hypoxia challenges in a preclinical SUDEP model involve orexin neurons. Neurobiol Dis 2024; 199:106592. [PMID: 38971479 DOI: 10.1016/j.nbd.2024.106592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 06/25/2024] [Accepted: 07/02/2024] [Indexed: 07/08/2024] Open
Abstract
Failure to recover from repeated hypercapnia and hypoxemia (HH) challenges caused by severe GCS and postictal apneas may contribute to sudden unexpected death in epilepsy (SUDEP). Our previous studies found orexinergic dysfunction contributes to respiratory abnormalities in a preclinical model of SUDEP, Kcna1-/- mice. Here, we developed two gas challenges consisting of repeated HH exposures and used whole body plethysmography to determine whether Kcna1-/- mice have detrimental ventilatory responses. Kcna1-/- mice exhibited an elevated ventilatory response to a mild repeated hypercapnia-hypoxia (HH) challenge compared to WT. Moreover, 71% of Kcna1-/- mice failed to survive a severe repeated HH challenge, whereas all WT mice recovered. We next determined whether orexin was involved in these differences. Pretreating Kcna1-/- mice with a dual orexin receptor antagonist rescued the ventilatory response during the mild challenge and all subjects survived the severe challenge. In ex vivo extracellular recordings in the lateral hypothalamus of coronal brain slices, we found reducing pH either inhibits or stimulates putative orexin neurons similar to other chemosensitive neurons; however, a significantly greater percentage of putative orexin neurons from Kcna1-/-mice were stimulated and the magnitude of stimulation was increased resulting in augmentation of the calculated chemosensitivity index relative to WT. Collectively, our data suggest that increased chemosensitive activity of orexin neurons may be pathologic in the Kcna1-/- mouse model of SUDEP, and contribute to elevated ventilatory responses. Our preclinical data suggest that those at high risk for SUDEP may be more sensitive to HH challenges, whether induced by seizures or other means; and the depth and length of the HH exposure could dictate the probability of survival.
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Affiliation(s)
- Shruthi H Iyer
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Jillian E Hinman
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Ted Warren
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Stephanie A Matthews
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Timothy A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA.
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Quintino C, Malheiros-Lima MR, Ghazale PP, Braga PPP, Maia OAC, de Oliveira CEG, Andrade FW, Schoorlemmer GH, Moreira TS, da Matta DH, Colugnati DB, Pansani AP. The latency to awake from induced-obstructive sleep apnea is reduced in rats with chronic epilepsy. Epilepsy Behav 2024; 157:109848. [PMID: 38823073 DOI: 10.1016/j.yebeh.2024.109848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 05/13/2024] [Accepted: 05/17/2024] [Indexed: 06/03/2024]
Abstract
OSA is known to increase the risk for SUDEP in persons with epilepsy, but the relationship between these two factors is not clear. Also, there is no study showing the acute responses to obstructive apnea in a chronic epilepsy model. Therefore, this study aimed to characterize cardiorespiratory responses to obstructive apnea and chemoreceptor stimulation in rats. In addition, we analyzed respiratory centers in the brain stem by immunohistochemistry. Epilepsy was induced with pilocarpine. About 30-60 days after the first spontaneous seizure, tracheal and thoracic balloons, and electrodes for recording the electroencephalogram, electromyogram, and electrocardiogram were implanted. Intermittent apneas were made by inflation of the tracheal balloon during wakefulness, NREM sleep, and REM sleep. During apnea, respiratory effort increased, and heart rate fell, especially with apneas made during wakefulness, both in control rats and rats with epilepsy. Latency to awake from apnea was longer with apneas made during REM than NREM, but rats with epilepsy awoke more rapidly than controls with apneas made during REM sleep. Rats with epilepsy also had less REM sleep. Cardiorespiratory responses to stimulation of carotid chemoreceptors with cyanide were similar in rats with epilepsy and controls. Immunohistochemical analysis of Phox2b, tryptophan hydroxylase, and NK1 in brain stem nuclei involved in breathing and sleep (retrotrapezoid nucleus, pre-Bötzinger complex, Bötzinger complex, and caudal raphe nuclei) revealed no differences between control rats and rats with epilepsy. In conclusion, our study showed that rats with epilepsy had a decrease in the latency to awaken from apneas during REM sleep, which may be related to neuroplasticity in some other brain regions related to respiratory control, awakening mechanisms, and autonomic modulation.
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Affiliation(s)
- Cláudio Quintino
- Department of Physiological Sciences, Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Milene R Malheiros-Lima
- Department of Physiology and Biophysics, Institute of Biomedical Science, Universidade de São Paulo, São Paulo, Brazil
| | - Poliana Peres Ghazale
- Department of Physiological Sciences, Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Pedro Paulo Pereira Braga
- Department of Physiological Sciences, Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Octávio A C Maia
- Department of Physiology and Biophysics, Institute of Biomedical Science, Universidade de São Paulo, São Paulo, Brazil
| | | | - Felipe Waks Andrade
- Institute of Mathematics and Statistics, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Guus H Schoorlemmer
- Physiology Department, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, Universidade de São Paulo, São Paulo, Brazil
| | | | - Diego Basile Colugnati
- Department of Physiological Sciences, Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Aline Priscila Pansani
- Department of Physiological Sciences, Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
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Purnell B, Bhasin J, Rust B, George S, Bah K, Lu T, Fedele D, Boison D. Disruption of adenosine metabolism increases risk of seizure-induced death despite decreased seizure severity. Epilepsia 2024. [PMID: 39018000 DOI: 10.1111/epi.18055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 06/19/2024] [Accepted: 06/19/2024] [Indexed: 07/18/2024]
Abstract
OBJECTIVE Respiratory arrest plays an important role in sudden unexpected death in epilepsy (SUDEP). Adenosine is of interest in SUDEP pathophysiology due to its influence on seizures and breathing. The objective of this investigation was to examine the role of adenosine in seizure severity, seizure-induced respiratory disruption, and seizure-induced death using mouse models. Understanding adenosinergic contributions to seizure cessation and seizure-induced death may provide insights into how SUDEP can be prevented while avoiding increased seizure severity. METHODS Our approach was to examine: (1) seizure severity and seizure-induced death after 15 mA electroshock seizures and during repeated pentylenetetrazol (PTZ) administration in wild-type mice (Adk+/+) and transgenic mice with reduced adenosine metabolism (Adk+/-); (2) the postictal hypercapnic ventilatory response (HCVR) in wild-type mice (the postictal HCVR could not be examined in Adk+/- mice due to their high mortality rate); and (3) the effects of adenosinergic drugs on seizure severity and seizure-induced death following maximal electroshock (MES). RESULTS Adk+/- mice were more vulnerable to seizure-induced death in the 15 mA electroshock and repeated PTZ models. Despite increased mortality, Adk+/- mice had comparable seizure severity in the PTZ model and reduced seizure severity in the 15 mA electroshock model. Breathing and HCVR were suppressed by 15 mA electroshock seizures in wild-type mice. Pharmacological inhibition of adenosine metabolism decreased MES seizure severity but did not increase mortality. A1 selective and nonselective adenosine receptor antagonists increased seizure-induced death following MES. SIGNIFICANCE Adenosine has opposing effects on seizure severity and seizure-induced death. On the one hand, our seizure severity data highlight the importance of adenosine in seizure suppression. On the other hand, our mortality data indicate that excessive extracellular adenosine signaling can increase the risk of seizure-induced respiratory arrest.
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Affiliation(s)
- Benton Purnell
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Jayant Bhasin
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Brian Rust
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Steven George
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Kadiatou Bah
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Tracy Lu
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Denise Fedele
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
- Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
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Purnell BS, Petrucci AN, Li R, Buchanan GF. Effect of adenosinergic manipulations on amygdala-kindled seizures in mice: Implications for sudden unexpected death in epilepsy. Epilepsia 2024. [PMID: 38980980 DOI: 10.1111/epi.18059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/11/2024]
Abstract
OBJECTIVE Sudden unexpected death in epilepsy (SUDEP) results in more years of potential life lost than any neurological condition with the exception of stroke. It is generally agreed that SUDEP happens due to some form of respiratory, cardiac, and electrocerebral dysfunction following a seizure; however, the mechanistic cause of these perturbations is unclear. One possible explanation lies with adenosinergic signaling. Extracellular levels of the inhibitory neuromodulator adenosine rapidly rise during seizures, a countermeasure that is necessary for seizure termination. Previous evidence has suggested that excessive adenosinergic inhibition could increase the risk of SUDEP by silencing brain areas necessary for life, such as the respiratory nuclei of the brainstem. The goal of this investigation was to further clarify the role of adenosine in seizure-induced respiratory and electrocerebral dysfunction. METHODS To determine the role of adenosine in postictal physiological dysregulation, we pharmacologically manipulated adenosine signaling prior to amygdala-kindled seizures in mice while recording electroencephalogram (EEG), electromyogram, and breathing using whole body plethysmography. The adenosinergic drugs used in this study included selective and nonselective adenosine receptor antagonists and inhibitors of adenosine metabolism. RESULTS We found that high doses of adenosine receptor antagonists caused some seizures to result in seizure-induced death; however, counterintuitively, animals in these conditions that did not experience seizure-induced death had little or no postictal generalized EEG suppression. Inhibitors of adenosine metabolism had no effect on postictal breathing but did worsen some postictal electrocerebral outcomes. SIGNIFICANCE The unexpected effect of high doses of adenosine antagonists on seizure-induced death observed in this study may be due to the increase in seizure severity, vasoconstriction, or phosphodiesterase inhibition caused by these drugs at high doses. These findings further clarify the role of adenosine in seizure-induced death and may have implications for the consumption of caffeine in epilepsy patients and the prevention of SUDEP.
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Affiliation(s)
- Benton S Purnell
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Alexandra N Petrucci
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Rui Li
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Gordon F Buchanan
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Boßelmann CM, Kegele J, Zerweck L, Klose U, Ethofer S, Roder C, Grimm AM, Hauser TK. Breath-Hold-Triggered BOLD fMRI in Drug-Resistant Nonlesional Focal Epilepsy-A Pilot Study. Clin Neuroradiol 2024; 34:315-324. [PMID: 38082172 PMCID: PMC11130005 DOI: 10.1007/s00062-023-01363-2] [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: 02/20/2023] [Accepted: 11/01/2023] [Indexed: 05/29/2024]
Abstract
PURPOSE Individuals with drug-resistant epilepsy may benefit from epilepsy surgery. In nonlesional cases, where no epileptogenic lesion can be detected on structural magnetic resonance imaging, multimodal neuroimaging studies are required. Breath-hold-triggered BOLD fMRI (bh-fMRI) was developed to measure cerebrovascular reactivity in stroke or angiopathy and highlights regional network dysfunction by visualizing focal impaired flow increase after vasodilatory stimulus. This regional dysfunction may correlate with the epileptogenic zone. In this prospective single-center single-blind pilot study, we aimed to establish the feasibility and safety of bh-fMRI in individuals with drug-resistant non-lesional focal epilepsy undergoing presurgical evaluation. METHODS In this prospective study, 10 consecutive individuals undergoing presurgical evaluation for drug-resistant focal epilepsy were recruited after case review at a multidisciplinary patient management conference. Electroclinical findings and results of other neuroimaging were used to establish the epileptogenic zone hypothesis. To calculate significant differences in cerebrovascular reactivity in comparison to the normal population, bh-fMRIs of 16 healthy volunteers were analyzed. The relative flow change of each volume of interest (VOI) of the atlas was then calculated compared to the flow change of the whole brain resulting in an atlas of normal cerebral reactivity. Consequently, the mean flow change of every VOI of each patient was tested against the healthy volunteers group. Areas with significant impairment of cerebrovascular reactivity had decreased flow change and were compared to the epileptogenic zone localization hypothesis in a single-blind design. RESULTS Acquisition of bh-fMRI was feasible in 9/10 cases, with one patient excluded due to noncompliance with breathing maneuvers. No adverse events were observed, and breath-hold for intermittent hypercapnia was well tolerated. On blinded review, we observed full or partial concordance of the local network dysfunction seen on bh-fMRI with the electroclinical hypothesis in 6/9 cases, including cases with extratemporal lobe epilepsy and those with nonlocalizing 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). CONCLUSION This represents the first report of bh-fMRI in individuals with epilepsy undergoing presurgical evaluation. We found bh-fMRI to be feasible and safe, with a promising agreement to electroclinical findings. Thus, bh-fMRI may represent a potential modality in the presurgical evaluation of epilepsy. Further studies are needed to establish clinical utility.
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Affiliation(s)
- Christian M Boßelmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
| | - Josua Kegele
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
| | - Leonie Zerweck
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076, Tuebingen, Germany
| | - Uwe Klose
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076, Tuebingen, Germany
| | - Silke Ethofer
- Department of Neurosurgery, University Hospital Tuebingen, Tuebingen, Germany
| | - Constantin Roder
- Department of Neurosurgery, University Hospital Tuebingen, Tuebingen, Germany
| | - Alexander M Grimm
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
| | - Till-Karsten Hauser
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076, Tuebingen, Germany.
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Umezu HL, Bittencourt-Silva PG, Mourão FAG, Moreira FA, Moraes MFD, Santos VR, da Silva GSF. Respiratory activity during seizures induced by pentylenetetrazole. Respir Physiol Neurobiol 2024; 323:104229. [PMID: 38307440 DOI: 10.1016/j.resp.2024.104229] [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: 11/25/2023] [Revised: 01/27/2024] [Accepted: 01/29/2024] [Indexed: 02/04/2024]
Abstract
This study investigated the respiratory activity in adult Wistar rats across different behavioral seizure severity induced by pentylenetetrazole (PTZ). Animals underwent surgery for electrodes implantation, allowing simultaneous EEG and diaphragm EMG (DIAEMG) recordings and the respiratory frequency and DIAEMG amplitude were measured. Seizures were acutely induced through PTZ injection and classified based on a pre-established score, with absence-like seizures (spike wave discharge (SWD) events on EEG) representing the lowest score. The respiratory activity was grouped into the different seizure severities. During absence-like and myoclonic jerk seizures, the breathing frequency decreased significantly (∼50% decrease) compared to pre- and post-ictal periods. Pronounced changes occurred with more severe seizures (clonic and tonic) with periods of apnea, especially during tonic seizures. Apnea duration was significantly higher in tonic compared to clonic seizures. Notably, during PTZ-induced tonic seizures the apnea events were marked by tonic DIAEMG contraction (tonic-phase apnea). In the majority of animals (5 out of 7) this was a fatal event in which the seizure-induced respiratory arrest preceded the asystole. In conclusion, we provide an assessment of the respiratory activity in the PTZ-induced acute seizures and showed that breathing dysfunction is more pronounced in seizures with higher severity.
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Affiliation(s)
- Hanna L Umezu
- Department of Physiology and Biophysics, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil
| | - Paloma G Bittencourt-Silva
- Department of Physiology and Biophysics, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil
| | - Flávio A G Mourão
- Department of Physiology and Biophysics, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil; Graduate Program in Neuroscience, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil
| | - Fabrício A Moreira
- Department of Pharmacology, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil
| | - Márcio Flávio D Moraes
- Department of Physiology and Biophysics, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil; Graduate Program in Neuroscience, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil
| | - Victor R Santos
- Department of Morphology, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil
| | - Glauber S F da Silva
- Department of Physiology and Biophysics, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), Belo Horizonte, Brazil.
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Bhandare AM, Dale N. Neural correlate of reduced respiratory chemosensitivity during chronic epilepsy. Front Cell Neurosci 2023; 17:1288600. [PMID: 38193031 PMCID: PMC10773801 DOI: 10.3389/fncel.2023.1288600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 11/27/2023] [Indexed: 01/10/2024] Open
Abstract
While central autonomic, cardiac, and/or respiratory dysfunction underlies sudden unexpected death in epilepsy (SUDEP), the specific neural mechanisms that lead to SUDEP remain to be determined. In this study, we took advantage of single-cell neuronal Ca2+ imaging and intrahippocampal kainic acid (KA)-induced chronic epilepsy in mice to investigate progressive changes in key cardiorespiratory brainstem circuits during chronic epilepsy. Weeks after induction of status epilepticus (SE), when mice were experiencing recurrent spontaneous seizures (chronic epilepsy), we observed that the adaptive ventilatory responses to hypercapnia were reduced for 5 weeks after SE induction with its partial recovery at week 7. These changes were paralleled by alterations in the chemosensory responses of neurons in the retrotrapezoid nucleus (RTN). Neurons that displayed adapting responses to hypercapnia were less prevalent and exhibited smaller responses over weeks 3-5, whereas neurons that displayed graded responses to hypercapnia became more prevalent by week 7. Over the same period, chemosensory responses of the presympathetic rostral ventrolateral medullary (RVLM) neurons showed no change. Mice with chronic epilepsy showed enhanced sensitivity to seizures, which invade the RTN and possibly put the chemosensory circuits at further risk of impairment. Our findings establish a dysfunctional breathing phenotype with its RTN neuronal correlate in mice with chronic epilepsy and suggest that the assessment of respiratory chemosensitivity may have the potential for identifying people at risk of SUDEP.
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Affiliation(s)
- Amol M. Bhandare
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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Harmata GI, Rhone AE, Kovach CK, Kumar S, Mowla MR, Sainju RK, Nagahama Y, Oya H, Gehlbach BK, Ciliberto MA, Mueller RN, Kawasaki H, Pattinson KT, Simonyan K, Davenport PW, Howard MA, Steinschneider M, Chan AC, Richerson GB, Wemmie JA, Dlouhy BJ. Failure to breathe persists without air hunger or alarm following amygdala seizures. JCI Insight 2023; 8:e172423. [PMID: 37788112 PMCID: PMC10721319 DOI: 10.1172/jci.insight.172423] [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: 05/24/2023] [Accepted: 09/29/2023] [Indexed: 10/05/2023] Open
Abstract
Postictal apnea is thought to be a major cause of sudden unexpected death in epilepsy (SUDEP). However, the mechanisms underlying postictal apnea are unknown. To understand causes of postictal apnea, we used a multimodal approach to study brain mechanisms of breathing control in 20 patients (ranging from pediatric to adult) undergoing intracranial electroencephalography for intractable epilepsy. Our results indicate that amygdala seizures can cause postictal apnea. Moreover, we identified a distinct region within the amygdala where electrical stimulation was sufficient to reproduce prolonged breathing loss persisting well beyond the end of stimulation. The persistent apnea was resistant to rising CO2 levels, and air hunger failed to occur, suggesting impaired CO2 chemosensitivity. Using es-fMRI, a potentially novel approach combining electrical stimulation with functional MRI, we found that amygdala stimulation altered blood oxygen level-dependent (BOLD) activity in the pons/medulla and ventral insula. Together, these findings suggest that seizure activity in a focal subregion of the amygdala is sufficient to suppress breathing and air hunger for prolonged periods of time in the postictal period, likely via brainstem and insula sites involved in chemosensation and interoception. They further provide insights into SUDEP, may help identify those at greatest risk, and may lead to treatments to prevent SUDEP.
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Affiliation(s)
- Gail I.S. Harmata
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Pharmacological Sciences Training Program
- Department of Psychiatry
| | | | | | | | | | | | | | - Hiroyuki Oya
- Department of Neurosurgery
- Iowa Neuroscience Institute
| | | | | | - Rashmi N. Mueller
- Department of Neurosurgery
- Department of Anesthesia, University of Iowa, Iowa City, Iowa, USA
| | | | - Kyle T.S. Pattinson
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Kristina Simonyan
- Department of Otolaryngology–Head and Neck Surgery, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | - Paul W. Davenport
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
| | - Matthew A. Howard
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
| | | | | | - George B. Richerson
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Department of Neurology
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
- Department of Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - John A. Wemmie
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
- Interdisciplinary Graduate Program in Neuroscience
- Department of Psychiatry
- Department of Internal Medicine
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Brian J. Dlouhy
- Department of Neurosurgery
- Iowa Neuroscience Institute
- Pappajohn Biomedical Institute
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Manis AD, Cook-Snyder DR, Duffy E, Osmani WA, Eilbes M, Dillard M, Palygin O, Staruschenko A, Hodges MR. Repeated seizures lead to progressive ventilatory dysfunction in SS Kcnj16-/- rats. J Appl Physiol (1985) 2023; 135:872-885. [PMID: 37535709 PMCID: PMC10642517 DOI: 10.1152/japplphysiol.00072.2023] [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: 02/06/2023] [Revised: 08/01/2023] [Accepted: 08/01/2023] [Indexed: 08/05/2023] Open
Abstract
Patients with uncontrolled epilepsy experience repeated seizures putting them at increased risk for sudden unexpected death in epilepsy (SUDEP). Data from human patients have led to the hypothesis that SUDEP results from severe cardiorespiratory suppression after a seizure, which may involve pathological deficiencies in the brainstem serotonin (5-HT) system. Rats with a genomic Kcnj16 mutation (SSKcnj16-/- rats) are susceptible to sound-induced generalized tonic-clonic seizures (GTCS) which, when repeated once daily for up to 10 days (10-day seizure protocol), increased mortality, particularly in male rats. Here, we test the hypothesis that repeated seizures across the 10-day protocol will cause a progressive ventilatory dysfunction due to time-dependent 5-HT deficiency. Initial severe seizures led to ictal and postictal apneas and transient decreases in breathing frequency, ventilatory drive, breath-to-breath variability, and brief hypoventilation. These seizure-induced effects on ventilation were exacerbated with increasing seizures and ventilatory chemoreflexes became further impaired after repeated seizures. Tissue analyses of key brainstem regions controlling breathing showed time-dependent 5-HT system suppression and increased immunoreactivity for IBA-1 (microglial marker) without changes in overall cell counts at 3, 7, and 10 days of seizures. Fluoxetine treatment in SSKcnj16-/- rats prevented repeated seizure-induced progressive respiratory suppression but failed to prevent seizure-related mortality. We conclude that repeated seizures cause a progressive compromise of ventilatory control in the immediate postictal period largely mediated by serotonin system suppression in brainstem regions of respiratory control. However, other unknown factors contribute to overall survival following repeated seizures in this model.NEW & NOTEWORTHY This study demonstrated that repeated seizures in a novel rat model (SSKcnj16-/- rats) caused a progressively greater ventilatory dysfunction in the immediate postictal period associated with brainstem serotonin (5-HT) suppression. Augmenting brain 5-HT with a selective serotonin reuptake inhibitor prevented the progressive ventilatory dysfunction induced by repeated seizures but failed to prevent seizure-related mortality, suggesting that repeated seizures may lead to cardiorespiratory suppression and failure through multiple mechanisms.
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Affiliation(s)
- Anna D Manis
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Denise R Cook-Snyder
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Erin Duffy
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Wasif A Osmani
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Melissa Eilbes
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Matthew Dillard
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Molecular Pharmacology & Physiology, University of South Florida, Tampa, Florida, United States
- James A. Haley Veterans' Hospital, Tampa, Florida, United States
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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Sainju RK, Dragon DN, Winnike HB, Vilella L, Li X, Lhatoo S, Eyck PT, Wendt LH, Richerson GB, Gehlbach BK. Interictal respiratory variability predicts severity of hypoxemia after generalized convulsive seizures. Epilepsia 2023; 64:2373-2384. [PMID: 37344924 PMCID: PMC10538446 DOI: 10.1111/epi.17691] [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: 04/05/2023] [Revised: 06/19/2023] [Accepted: 06/19/2023] [Indexed: 06/23/2023]
Abstract
OBJECTIVE Severe respiratory dysfunction induced by generalized convulsive seizures (GCS) is now thought to be a common mechanism for sudden unexpected death in epilepsy (SUDEP). In a mouse model of seizure-induced death, increased interictal respiratory variability was reported in mice that later died of respiratory arrest after GCS. We studied respiratory variability in epilepsy patients as a predictive tool for severity of postictal hypoxemia, a potential biomarker for SUDEP risk. We then explored the relationship between respiratory variability and central CO2 drive, measured by the hypercapnic ventilatory response (HCVR). METHODS We reviewed clinical, video-electroencephalography, and respiratory (belts, airflow, pulse oximeter, and HCVR) data of epilepsy patients. Mean, SD, and coefficient of variation (CV) of interbreath interval (IBI) were calculated. Primary outcomes were: (1) nadir of capillary oxygen saturation (SpO2 ) and (2) duration of oxygen desaturation. Poincaré plots of IBI were created. Covariates were evaluated in univariate models, then, based on Akaike information criteria (AIC), multivariate regression models were created. RESULTS Of 66 GCS recorded in 131 subjects, 30 had interpretable respiratory data. In the multivariate model with the lowest AIC value, duration of epilepsy was a significant predictor of duration of oxygen desaturation. Duration of tonic phase and CV of IBI during the third postictal minute correlated with SpO2 nadir, whereas CV of IBI during non-rapid eye movement sleep had a negative correlation. Poincaré plots showed that long-term variability was significantly greater in subjects with ≥200 s of postictal oxygen desaturation after GCS compared to those with <200 s desaturation. Finally, HCVR slope showed a negative correlation with measures of respiratory variability. SIGNIFICANCE These results indicate that interictal respiratory variability predicts severity of postictal oxygen desaturation, suggesting its utility as a potential biomarker. They also suggest that interictal respiratory control may be abnormal in some patients with epilepsy.
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Affiliation(s)
- Rup K. Sainju
- Department of Neurology University of Iowa Hospitals and Clinics, Iowa City, IA
| | - Deidre N. Dragon
- Department of Neurology University of Iowa Hospitals and Clinics, Iowa City, IA
| | - Harold B. Winnike
- Institute for Clinical and Translational Science University of Iowa, Iowa City, IA
| | - Laura Vilella
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX
| | - Xiaojin Li
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX
| | - Samden Lhatoo
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX
| | - Patrick Ten Eyck
- Institute for Clinical and Translational Science University of Iowa, Iowa City, IA
| | - Linder H Wendt
- Institute for Clinical and Translational Science University of Iowa, Iowa City, IA
| | - George B. Richerson
- Department of Neurology University of Iowa Hospitals and Clinics, Iowa City, IA
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA
- Iowa Neuroscience Institute, University of Iowa, IA
- VA Medical Center, Iowa City, IA
| | - Brian K. Gehlbach
- Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA
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12
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Teran FA, Sainju RK, Bravo E, Wagnon J, Kim Y, Granner A, Gehlbach BK, Richerson GB. Seizures Cause Prolonged Impairment of Ventilation, CO 2 Chemoreception and Thermoregulation. J Neurosci 2023; 43:4959-4971. [PMID: 37160367 PMCID: PMC10324997 DOI: 10.1523/jneurosci.0450-23.2023] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/24/2023] [Accepted: 04/30/2023] [Indexed: 05/11/2023] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) has been linked to respiratory dysfunction, but the mechanisms underlying this association remain unclear. Here we found that both focal and generalized convulsive seizures (GCSs) in epilepsy patients caused a prolonged decrease in the hypercapnic ventilatory response (HCVR; a measure of respiratory CO2 chemoreception). We then studied Scn1a R1407X/+ (Dravet syndrome; DS) and Scn8a N1768D/+ (D/+) mice of both sexes, two models of SUDEP, and found that convulsive seizures caused a postictal decrease in ventilation and severely depressed the HCVR in a subset of animals. Those mice with severe postictal depression of the HCVR also exhibited transient postictal hypothermia. A combination of blunted HCVR and abnormal thermoregulation is known to occur with dysfunction of the serotonin (5-hydroxytryptamine; 5-HT) system in mice. Depleting 5-HT with para-chlorophenylalanine (PCPA) mimicked seizure-induced hypoventilation, partially occluded the postictal decrease in the HCVR, exacerbated hypothermia, and increased postictal mortality in DS mice. Conversely, pretreatment with the 5-HT agonist fenfluramine reduced postictal inhibition of the HCVR and hypothermia. These results are consistent with the previous observation that seizures cause transient impairment of serotonergic neuron function, which would be expected to inhibit the many aspects of respiratory control dependent on 5-HT, including baseline ventilation and the HCVR. These results provide a scientific rationale to investigate the interictal and/or postictal HCVR as noninvasive biomarkers for those at high risk of seizure-induced death, and to prevent SUDEP by enhancing postictal 5-HT tone.SIGNIFICANCE STATEMENT There is increasing evidence that seizure-induced respiratory dysfunction contributes to the pathophysiology of sudden unexpected death in epilepsy (SUDEP). However, the cellular basis of this dysfunction has not been defined. Here, we show that seizures impair CO2 chemoreception in some epilepsy patients. In two mouse models of SUDEP we found that generalized convulsive seizures impaired CO2 chemoreception, and induced hypothermia, two effects reported with serotonergic neuron dysfunction. The defects in chemoreception and thermoregulation were exacerbated by chemical depletion of serotonin and reduced with fenfluramine, suggesting that seizure-induced respiratory dysfunction may be due to impairment of serotonin neuron function. These findings suggest that impaired chemoreception because of transient inhibition of serotonergic neurons may contribute to the pathophysiology of SUDEP.
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Affiliation(s)
- Frida A Teran
- Department of Neurology, University of Iowa, Iowa City, Iowa 52242
- Medical Scientist Training Program, University of Iowa, Iowa City, Iowa 52242
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
| | - Rup K Sainju
- Department of Neurology, University of Iowa, Iowa City, Iowa 52242
| | - Eduardo Bravo
- Department of Neurology, University of Iowa, Iowa City, Iowa 52242
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
| | - Jacy Wagnon
- Department of Neuroscience, The Ohio State University, Columbus, Ohio 43210
| | - YuJaung Kim
- Department of Neurology, University of Iowa, Iowa City, Iowa 52242
| | - Alex Granner
- Department of Neurology, University of Iowa, Iowa City, Iowa 52242
| | - Brian K Gehlbach
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242
| | - George B Richerson
- Department of Neurology, University of Iowa, Iowa City, Iowa 52242
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
- Neurology, Veterans Affairs Medical Center, Iowa City, Iowa 52242
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13
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Crone SA, Dlouhy BJ, Gross C, Ray RS. Editorial: Forebrain control of breathing and sudden death in epilepsy. Front Neural Circuits 2023; 17:1212172. [PMID: 37288286 PMCID: PMC10242160 DOI: 10.3389/fncir.2023.1212172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 05/09/2023] [Indexed: 06/09/2023] Open
Affiliation(s)
- Steven A. Crone
- Division of Pediatric Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Brian J. Dlouhy
- Department of Neurosurgery, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA, United States
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Russell S. Ray
- Memory Brain Research Center, Baylor College of Medicine, Houston, TX, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
- McNair Medical Institute, Houston, TX, United States
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14
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Kassinopoulos M, Rolandi N, Alphan L, Harper RM, Oliveira J, Scott C, Kozák LR, Guye M, Lemieux L, Diehl B. Brain Connectivity Correlates of Breathing and Cardiac Irregularities in SUDEP: A Resting-State fMRI Study. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.19.541412. [PMID: 37293113 PMCID: PMC10245782 DOI: 10.1101/2023.05.19.541412] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of premature mortality among people with epilepsy. Evidence from witnessed and monitored SUDEP cases indicate seizure-induced cardiovascular and respiratory failures; yet, the underlying mechanisms remain obscure. SUDEP occurs often during the night and early morning hours, suggesting that sleep or circadian rhythm-induced changes in physiology contribute to the fatal event. Resting-state fMRI studies have found altered functional connectivity between brain structures involved in cardiorespiratory regulation in later SUDEP cases and in individuals at high-risk of SUDEP. However, those connectivity findings have not been related to changes in cardiovascular or respiratory patterns. Here, we compared fMRI patterns of brain connectivity associated with regular and irregular cardiorespiratory rhythms in SUDEP cases with those of living epilepsy patients of varying SUDEP risk, and healthy controls. We analysed resting-state fMRI data from 98 patients with epilepsy (9 who subsequently succumbed to SUDEP, 43 categorized as low SUDEP risk (no tonic-clonic seizures (TCS) in the year preceding the fMRI scan), and 46 as high SUDEP risk (>3 TCS in the year preceding the scan)) and 25 healthy controls. The global signal amplitude (GSA), defined as the moving standard deviation of the fMRI global signal, was used to identify periods with regular ('low state') and irregular ('high state') cardiorespiratory rhythms. Correlation maps were derived from seeds in twelve regions with a key role in autonomic or respiratory regulation, for the low and high states. Following principal component analysis, component weights were compared between the groups. We found widespread alterations in connectivity of precuneus/posterior cingulate cortex in epilepsy compared to controls, in the low state (regular cardiorespiratory activity). In the low state, and to a lesser degree in the high state, reduced anterior insula connectivity (mainly with anterior and posterior cingulate cortex) in epilepsy appeared, relative to healthy controls. For SUDEP cases, the insula connectivity differences were inversely related to the interval between the fMRI scan and death. The findings suggest that anterior insula connectivity measures may provide a biomarker of SUDEP risk. The neural correlates of autonomic brain structures associated with different cardiorespiratory rhythms may shed light on the mechanisms underlying terminal apnea observed in SUDEP.
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Affiliation(s)
- Michalis Kassinopoulos
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Epilepsy Society, Chalfont St. Peter, Buckinghamshire, United Kingdom
| | - Nicolo Rolandi
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Epilepsy Society, Chalfont St. Peter, Buckinghamshire, United Kingdom
| | - Laren Alphan
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Ronald M. Harper
- UCLA Brain Research Institute, Los Angeles, CA, United States
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Joana Oliveira
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, UCLH, London, United Kingdom
| | - Catherine Scott
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, UCLH, London, United Kingdom
| | - Lajos R. Kozák
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Neuroradiology, Medical Imaging Centre, Semmelweis University, Budapest, Hungary
| | - Maxime Guye
- Aix Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France
- APHM, Hôpital de la Timone, CEMEREM, Marseille, France
| | - Louis Lemieux
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Epilepsy Society, Chalfont St. Peter, Buckinghamshire, United Kingdom
| | - Beate Diehl
- UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Epilepsy Society, Chalfont St. Peter, Buckinghamshire, United Kingdom
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15
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Giannoni A, Borrelli C, Gentile F, Sciarrone P, Spießhöfer J, Piepoli M, Richerson GB, Floras JS, Coats AJS, Javaheri S, Emdin M, Passino C. Autonomic and respiratory consequences of altered chemoreflex function: clinical and therapeutic implications in cardiovascular diseases. Eur J Heart Fail 2023; 25:642-656. [PMID: 36907827 PMCID: PMC10989193 DOI: 10.1002/ejhf.2819] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 02/10/2023] [Accepted: 02/26/2023] [Indexed: 03/14/2023] Open
Abstract
The importance of chemoreflex function for cardiovascular health is increasingly recognized in clinical practice. The physiological function of the chemoreflex is to constantly adjust ventilation and circulatory control to match respiratory gases to metabolism. This is achieved in a highly integrated fashion with the baroreflex and the ergoreflex. The functionality of chemoreceptors is altered in cardiovascular diseases, causing unstable ventilation and apnoeas and promoting sympathovagal imbalance, and it is associated with arrhythmias and fatal cardiorespiratory events. In the last few years, opportunities to desensitize hyperactive chemoreceptors have emerged as potential options for treatment of hypertension and heart failure. This review summarizes up to date evidence of chemoreflex physiology/pathophysiology, highlighting the clinical significance of chemoreflex dysfunction, and lists the latest proof of concept studies based on modulation of the chemoreflex as a novel target in cardiovascular diseases.
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Affiliation(s)
- Alberto Giannoni
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
| | | | - Francesco Gentile
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
| | | | - Jens Spießhöfer
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- University of Aachen, Aachen, Germany
| | | | | | - John S Floras
- Division of Cardiology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
| | | | - Shahrokh Javaheri
- Division of Pulmonary and Sleep Medicine, Bethesda North Hospital, Cincinnati, Ohio, Division of Pulmonary, Critical Care and Sleep Medicine, University of Cincinnati, Cincinnati, Ohio, and Division of Cardiology, The Ohio State University, Columbus, Ohio USA
| | - Michele Emdin
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
| | - Claudio Passino
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
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16
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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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17
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Abstract
PURPOSE OF REVIEW Sudden unexpected death in epilepsy (SUDEP) is a leading cause of death in patients with epilepsy. This review highlights the recent literature regarding epidemiology on a global scale, putative mechanisms and thoughts towards intervention and prevention. RECENT FINDINGS Recently, numerous population-based studies have examined the incidence of SUDEP in many countries. Remarkably, incidence is quite consistent across these studies, and is commensurate with the recent estimates of about 1.2 per 1000 patient years. These studies further continue to support that incidence is similar across the ages and that comparable factors portend heightened risk for SUDEP. Fervent research in patients and animal studies continues to hone the understanding of potential mechanisms for SUDEP, especially those regarding seizure-induced respiratory dysregulation. Many of these studies and others have begun to lay out a path towards identification of improved treatment and prevention means. However, continued efforts are needed to educate medical professionals about SUDEP risk and the need to disclose this to patients. SUMMARY SUDEP is a devastating potential outcome of epilepsy. More is continually learned about risk and mechanisms from clinical and preclinical studies. This knowledge can hopefully be leveraged into preventive measures in the near future.
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Affiliation(s)
- Gordon F Buchanan
- Department of Neurology
- Neuroscience Graduate Program
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Ana T Novella Maciel
- Department of Neurology
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Universidad Nacional Autónoma de México, Mexico City, México
| | - Matthew J Summerfield
- Neuroscience Graduate Program
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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18
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Bauer J, Devinsky O, Rothermel M, Koch H. Autonomic dysfunction in epilepsy mouse models with implications for SUDEP research. Front Neurol 2023; 13:1040648. [PMID: 36686527 PMCID: PMC9853197 DOI: 10.3389/fneur.2022.1040648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/12/2022] [Indexed: 01/09/2023] Open
Abstract
Epilepsy has a high prevalence and can severely impair quality of life and increase the risk of premature death. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in drug-resistant epilepsy and most often results from respiratory and cardiac impairments due to brainstem dysfunction. Epileptic activity can spread widely, influencing neuronal activity in regions outside the epileptic network. The brainstem controls cardiorespiratory activity and arousal and reciprocally connects to cortical, diencephalic, and spinal cord areas. Epileptic activity can propagate trans-synaptically or via spreading depression (SD) to alter brainstem functions and cause cardiorespiratory dysfunction. The mechanisms by which seizures propagate to or otherwise impair brainstem function and trigger the cascading effects that cause SUDEP are poorly understood. We review insights from mouse models combined with new techniques to understand the pathophysiology of epilepsy and SUDEP. These techniques include in vivo, ex vivo, invasive and non-invasive methods in anesthetized and awake mice. Optogenetics combined with electrophysiological and optical manipulation and recording methods offer unique opportunities to study neuronal mechanisms under normal conditions, during and after non-fatal seizures, and in SUDEP. These combined approaches can advance our understanding of brainstem pathophysiology associated with seizures and SUDEP and may suggest strategies to prevent SUDEP.
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Affiliation(s)
- Jennifer Bauer
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany,Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Orrin Devinsky
- Departments of Neurology, Neurosurgery and Psychiatry, NYU Langone School of Medicine, New York, NY, United States
| | - Markus Rothermel
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Henner Koch
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany,*Correspondence: Henner Koch ✉
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Carotid body stimulation as a potential intervention in sudden death in epilepsy. Epilepsy Behav 2022; 136:108918. [PMID: 36202052 PMCID: PMC10187768 DOI: 10.1016/j.yebeh.2022.108918] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 09/09/2022] [Accepted: 09/11/2022] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To investigate carotid body (CB) mechanisms related to sudden death during seizure. Ictal activation of oxygen-conserving reflexes (OCRs) can trigger fatal cardiorespiratory collapse in seizing rats, which presents like human sudden unexpected death in epilepsy (SUDEP). The CB is strongly implicated in OCR pathways; we hypothesize that modulating CB activity will provide insight into these mechanisms of death. METHODS Long-Evans rats were anesthetized with urethane. Recordings included: electrocorticography, electrocardiography, respiration via nasal thermocouple, and blood pressure (BP). The mammalian diving reflex (MDR) was activated by cold water delivered through a nasal cannula. Reflex and stimulation trials were repeated up to 16 times (4 pre-intervention, 12 post-intervention) or until death. In some animals, one or both carotid bodies were denervated. In some animals, the CB was electrically stimulated, both with and without MDR. Seizures were induced with kainic acid (KA). RESULTS Animals without seizure and with no CB modulation survived all reflexes. Non-seizing animals with CB denervation survived 7.1 ± 5.4 reflexes before death, and only 1 of 7 survived past the 12-trial threshold. Electrical CB stimulation without seizure and without reflex caused significant tachypnea and hypotension. Electrical CB stimulation with seizure and without reflex required higher amplitudes to replicate the physiological responses seen outside seizure. Seizing animals without CB intervention survived 3.2 ± 3.6 trials (per-reflex survival rate 42.0% ± 44.4%), and 0 of 7 survived past the 12-trial threshold. Seizing animals with electrical CB stimulation survived 10.5 ± 4.7 ictal trials (per-reflex survival rate 86.3% ± 35.0%), and 6 of 8 survived past the 12-trial threshold. SIGNIFICANCE These results suggest that, during seizure, the ability of the CB to stimulate a restart of respiration is impaired. The CB and its afferents may be relevant to fatal ictal apnea and SUDEP in humans, and CB stimulation may be a relevant intervention technique in these deaths.
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Brown JC, Boat R, Williams NC, Johnson MA, Sharpe GR. The effect of trait self-control on dyspnoea and tolerance to a CO 2 rebreathing challenge in healthy males and females. Physiol Behav 2022; 255:113944. [PMID: 35973643 DOI: 10.1016/j.physbeh.2022.113944] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/28/2022] [Accepted: 08/12/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND High trait self-control is associated with greater tolerance of unpleasant sensations including effort and pain. Dyspnoea and pain have several commonalities and this study aimed to investigate for the first time whether trait self-control influences responses to a hypercapnic rebreathing challenge designed to induce dyspnoea. As sex also influences tolerance to dyspnoea, we also sought to investigate whether this moderated the role of trait self-control. METHODS Participants (n = 65, 32 females) scoring high or low for trait self-control, performed a standardised rebreathing challenge, in which inspired carbon dioxide (CO2) gradually increased over a period of 6 min or until an intolerable level of dyspnoea. Air hunger (AH) intensity - a distinctive quality of dyspnoea, was measured every 30 s. The multidimensional dyspnoea profile (MDP) was completed after the rebreathing challenge for a more complete overview of breathing discomfort. RESULTS Males high in trait self-control (SCHIGH) (302 ± 42 s), tolerated the rebreathing challenge for longer than males low in self-control (SCLOW) (252 ± 66 s, P = 0.021), experienced slower increases in AH intensity during the rebreathing challenge (0.03 ± 0.01 cm.s - 1 vs. 0.04 ± 0.01 cm.s - 1,P = 0.045) and reported lower perceived mental effort on the MDP (4.94 ± 2.46 vs. 7.06 ± 1.60, P = 0.007). There was no difference between SCHIGH and SCLOW females for challenge duration. However, SCHIGH females (9.29 ± 0.66 cm) reported greater air hunger at the end of the challenge than SCLOW females (7.75 ± 1.75 cm, P = 0.003). It is possible that SCLOW females were unwilling to tolerate the same perceptual intensity of AH as the SCHIGH females. CONCLUSIONS These results indicate that individuals high in trait self-control are more tolerant of dyspnoea during a CO2 rebreathing challenge than low self-control individuals. Tolerance of the stimulus was moderated by the sex of the participant, presenting an interesting opportunity for future research.
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Affiliation(s)
- J C Brown
- Department of Sport Science, Clifton Campus, Nottingham Trent University, Nottingham, United Kingdom.
| | - R Boat
- Department of Sport Science, Clifton Campus, Nottingham Trent University, Nottingham, United Kingdom
| | - N C Williams
- Department of Sport Science, Clifton Campus, Nottingham Trent University, Nottingham, United Kingdom
| | - M A Johnson
- Department of Sport Science, Clifton Campus, Nottingham Trent University, Nottingham, United Kingdom
| | - G R Sharpe
- Department of Sport Science, Clifton Campus, Nottingham Trent University, Nottingham, United Kingdom
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21
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Hupp NJ, Talavera B, Melius S, Lacuey N, Lhatoo SD. Protocols for multimodal polygraphy for cardiorespiratory monitoring in the epilepsy monitoring unit. Part II - Research acquisition. Epilepsy Res 2022; 185:106987. [PMID: 35843018 DOI: 10.1016/j.eplepsyres.2022.106987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/29/2022] [Accepted: 07/07/2022] [Indexed: 11/30/2022]
Abstract
Multimodal polygraphy including cardiorespiratory monitoring is a valuable tool for epilepsy and sudden unexpected death in epilepsy (SUDEP) research. Broader applications in research into stress, anxiety, mood and other domains exist. Polygraphy techniques used during video electroencephalogram (EEG) recordings provide information on cardiac and respiratory changes in the peri-ictal period. In addition, such monitoring in brain mapping during chronic intracranial EEG evaluations has helped the understanding of pathomechanisms that lead to seizure induced cardiorespiratory dysfunction. Our aim here is to provide protocols and information on devices that may be used in the Epilepsy Monitoring Unit, in addition to proposed standard of care data acquisition. These devices include oronasal thermistors, oronasal pressure transducers, capnography, transcutaneous CO2 sensors, and continuous noninvasive blood pressure monitoring. Standard protocols for cardiorespiratory monitoring simultaneously with video EEG recording, may be useful in the study of cardiorespiratory phenomena in persons with epilepsy.
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Affiliation(s)
- Norma J Hupp
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, TX, USA
| | - Blanca Talavera
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, TX, USA.
| | - Stephen Melius
- Memorial Hermann. Texas Medical Center, Houston, TX, USA
| | - Nuria Lacuey
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, TX, USA
| | - Samden D Lhatoo
- Texas Institute of Restorative Neurotechnologies (TIRN), University of Texas Health Science Center (UTHealth), Houston, TX, USA
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22
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Joyal KG, Kreitlow BL, Buchanan GF. The role of sleep state and time of day in modulating breathing in epilepsy: implications for sudden unexpected death in epilepsy. Front Neural Circuits 2022; 16:983211. [PMID: 36082111 PMCID: PMC9445500 DOI: 10.3389/fncir.2022.983211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among patients with refractory epilepsy. While the exact etiology of SUDEP is unknown, mounting evidence implicates respiratory dysfunction as a precipitating factor in cases of seizure-induced death. Dysregulation of breathing can occur in epilepsy patients during and after seizures as well as interictally, with many epilepsy patients exhibiting sleep-disordered breathing (SDB), such as obstructive sleep apnea (OSA). The majority of SUDEP cases occur during the night, with the victim found prone in or near a bed. As breathing is modulated in both a time-of-day and sleep state-dependent manner, it is relevant to examine the added burden of nocturnal seizures on respiratory function. This review explores the current state of understanding of the relationship between respiratory function, sleep state and time of day, and epilepsy. We highlight sleep as a particularly vulnerable period for individuals with epilepsy and press that this topic warrants further investigation in order to develop therapeutic interventions to mitigate the risk of SUDEP.
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Affiliation(s)
- Katelyn G. Joyal
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Benjamin L. Kreitlow
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Medical Scientist Training Program, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gordon F. Buchanan
- Interdisciplinary Graduate Program in Neuroscience, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- Medical Scientist Training Program, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- *Correspondence: Gordon F. Buchanan
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23
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Hampson JP, Lacuey N, Rani MRS, Hampson JS, Simeone KA, Simeone TA, Narayana PA, Lemieux L, Lhatoo SD. Functional MRI Correlates of Carbon Dioxide Chemosensing in Persons With Epilepsy. Front Neurol 2022; 13:896204. [PMID: 35873766 PMCID: PMC9301231 DOI: 10.3389/fneur.2022.896204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/03/2022] [Indexed: 11/17/2022] Open
Abstract
Objectives Sudden unexpected death in epilepsy (SUDEP) is a catastrophic epilepsy outcome for which there are no reliable premortem imaging biomarkers of risk. Percival respiratory depression is seen in monitored SUDEP and near SUDEP cases, and abnormal chemosensing of raised blood carbon dioxide (CO2) is thought to contribute. Damage to brainstem respiratory control and chemosensing structures has been demonstrated in structural imaging and neuropathological studies of SUDEP. We hypothesized that functional MRI (fMRI) correlates of abnormal chemosensing are detectable in brainstems of persons with epilepsy (PWE) and are different from healthy controls (HC). Methods We analyzed fMRI BOLD activation and brain connectivity in 10 PWE and 10 age- and sex-matched HCs during precisely metered iso-oxic, hypercapnic breathing challenges. Segmented brainstem responses were of particular interest, along with characterization of functional connectivity metrics between these structures. Regional BOLD activations during hypercapnic challenges were convolved with hemodynamic responses, and the resulting activation maps were passed on to group-level analyses. For the functional connectivity analysis, significant clusters from BOLD results were used as seeds. Each individual seed time-series activation map was extracted for bivariate correlation coefficient analyses to study changes in brain connectivity between PWE and HCs. Results (1) Greater brainstem BOLD activations in PWE were observed compared to HC during hypercapnic challenges in several structures with respiratory/chemosensing properties. Group comparison between PWE vs. HC showed significantly greater activation in the dorsal raphe among PWE (p < 0.05) compared to HCs. (2) PWE had significantly greater seed-seed connectivity and recruited more structures during hypercapnia compared to HC. Significance The results of this study show that BOLD responses to hypercapnia in human brainstem are detectable and different in PWE compared to HC. Increased dorsal raphe BOLD activation in PWE and increased seed-seed connectivity between brainstem and adjacent subcortical areas may indicate abnormal chemosensing in these individuals. Imaging investigation of brainstem respiratory centers involved in respiratory regulation in PWE is an important step toward identifying suspected dysfunction of brainstem breathing control that culminates in SUDEP and deserve further study as potential imaging SUDEP biomarkers.
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Affiliation(s)
- Johnson P. Hampson
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Nuria Lacuey
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - MR Sandhya Rani
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Jaison S. Hampson
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Kristina A. Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, United States
| | - Timothy A. Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE, United States
| | - Ponnada A. Narayana
- Department of Diagnostic and Interventional Imaging, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Louis Lemieux
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Samden D. Lhatoo
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States
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24
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Teran FA, Bravo E, Richerson GB. Sudden unexpected death in epilepsy: Respiratory mechanisms. HANDBOOK OF CLINICAL NEUROLOGY 2022; 189:153-176. [PMID: 36031303 PMCID: PMC10191258 DOI: 10.1016/b978-0-323-91532-8.00012-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Epilepsy is one of the most common chronic neurologic diseases, with a prevalence of 1% in the US population. Many people with epilepsy live normal lives, but are at risk of sudden unexpected death in epilepsy (SUDEP). This mysterious comorbidity of epilepsy causes premature death in 17%-50% of those with epilepsy. Most SUDEP occurs after a generalized seizure, and patients are typically found in bed in the prone position. Until recently, it was thought that SUDEP was due to cardiovascular failure, but patients who died while being monitored in hospital epilepsy units revealed that most SUDEP is due to postictal central apnea. Some cases may occur when seizures invade the amygdala and activate projections to the brainstem. Evidence suggests that the pathophysiology is linked to defects in the serotonin system and central CO2 chemoreception, and that there is considerable overlap with mechanisms thought to be involved in sudden infant death syndrome (SIDS). Future work is needed to identify biomarkers for patients at highest risk, improve ascertainment, develop methods to alert caregivers when SUDEP is imminent, and find effective approaches to prevent these fatal events.
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Affiliation(s)
- Frida A Teran
- Department of Neurology, University of Iowa, Iowa City, IA, United States; Medical Scientist Training Program, University of Iowa, Iowa City, IA, United States.
| | - Eduardo Bravo
- Department of Neurology, University of Iowa, Iowa City, IA, United States
| | - George B Richerson
- Department of Neurology, University of Iowa, Iowa City, IA, United States; Department of Molecular Physiology & Biophysics, University of Iowa, Iowa City, IA, United States
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25
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Sainju R, Dragon D, Winnike H, Eyck P, Granner M, Gehlbach B, Richerson G. Use of Fluoxetine to Augment the Inter-Ictal Hypercapnic Ventilatory Response in Patients with Epilepsy: A Pilot Study. Neurol India 2022; 70:2125-2129. [PMID: 36352620 DOI: 10.4103/0028-3886.359160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Background Severe peri-ictal respiratory dysfunction is a potential biomarker for high SUDEP risk and correlates with an attenuated hypercapnic ventilatory response (HCVR). Prior studies suggest a potential role for selective serotonergic reuptake inhibitors in modifying the HCVR, but this approach has not been studied in the epilepsy population. Objectives To assess the feasibility of using fluoxetine to augment HCVR in epilepsy patients. Methods and Material An inter-ictal HCVR was measured using a CO2 rebreathing technique in patients with epilepsy aged 18-75 years. Eligible participants were randomized to fluoxetine or placebo, and the HCVR was repeated at the end of week 4. Primary outcomes were recruitment and retention rate. Results Of the 30 subjects enrolled, 22 were randomized (mean: 3.8 subjects/3 months), with a retention rate of 100% in fluoxetine and 95% in placebo. Conclusions Our results demonstrate feasibility for a larger definitive future study to assess the efficacy of fluoxetine in augmenting HCVR.
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26
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Patodia S, Somani A, Thom M. Review: Neuropathology findings in autonomic brain regions in SUDEP and future research directions. Auton Neurosci 2021; 235:102862. [PMID: 34411885 PMCID: PMC8455454 DOI: 10.1016/j.autneu.2021.102862] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/16/2021] [Accepted: 07/24/2021] [Indexed: 12/21/2022]
Abstract
Autonomic dysfunction is implicated from clinical, neuroimaging and experimental studies in sudden and unexpected death in epilepsy (SUDEP). Neuropathological analysis in SUDEP series enable exploration of acquired, seizure-related cellular adaptations in autonomic and brainstem autonomic centres of relevance to dysfunction in the peri-ictal period. Alterations in SUDEP compared to control groups have been identified in the ventrolateral medulla, amygdala, hippocampus and central autonomic regions. These involve neuropeptidergic, serotonergic and adenosine systems, as well as specific regional astroglial and microglial populations, as potential neuronal modulators, orchestrating autonomic dysfunction. Future research studies need to extend to clinically and genetically characterized epilepsies, to explore if common or distinct pathways of autonomic dysfunction mediate SUDEP. The ultimate objective of SUDEP research is the identification of disease biomarkers for at risk patients, to improve post-mortem recognition and disease categorisation, but ultimately, for exposing potential treatment targets of pharmacologically modifiable and reversible cellular alterations.
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Affiliation(s)
- Smriti Patodia
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Alyma Somani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.
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27
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Sainju RK, Dragon DN, Winnike HB, Ten Eyck P, Granner MA, Gehlbach BK, Richerson GB. Hypercapnic ventilatory response in epilepsy patients treated with VNS: A case-control study. Epilepsia 2021; 62:e140-e146. [PMID: 34265074 PMCID: PMC9113047 DOI: 10.1111/epi.16997] [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: 02/24/2021] [Revised: 06/23/2021] [Accepted: 06/23/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Central CO2 chemoreception (CCR), a major chemical drive for breathing, can be quantified with a CO2 re-breathing test to measure the hypercapnic ventilatory response (HCVR). An attenuated HCVR correlates with the severity of respiratory dysfunction after generalized convulsive seizures and is a potential biomarker for sudden unexpected death in epilepsy (SUDEP) risk. Vagus nerve stimulation (VNS) may reduce SUDEP risk, but for unclear reasons the risk remains higher during the first 2 years after implantation. The vagus nerve has widespread connections in the brainstem, including key areas related to CCR. Here we examined whether chronic electrical stimulation of the vagus nerve induces changes in CCR. METHODS We compared the HCVR in epilepsy patients with or without an active VNS in a sex- and age-matched case-control study. Eligible subjects were selected from a cohort of patients who previously underwent HCVR testing. The HCVR slope, change in minute ventilation (VE) with respect to change in end tidal (ET) CO2 (∆ VE/ ∆ ETCO2) during the test was calculated for each subject. Key variables were compared between the two groups. Univariate and multivariate analyses were carried out for HCVR slope as dependent variable. RESULTS A total of 86 subjects were in the study. HCVR slope was significantly lower in the cases compared to the controls. Cases had longer duration of epilepsy and higher number of anti-epileptic drugs (AEDs) tried during lifetime. Having active VNS and ETCO2 were associated with a low HCVR slope while high BMI was associated with high HCVR slope in both univariate and multivariate analyses. DISCUSSION We found having an active VNS was associated with relatively attenuated HCVR slope. Although duration of epilepsy and number of AEDs tried during lifetime was significantly different between the groups, they were not predictors of HCVR slope in subsequent analysis. CONCLUSION Chronic electrical stimulation of the vagus nerve by VNS may be associated with an attenuated CCR [Correction added on 24 November 2021, after first online publication: The preceding sentence has been revised from “Chronic electrical stimulation of VNS nerve by VNS…”]. A larger prospective study may help to establish the time course of this effect in relation to the time of VNS implantation, whether there is a causal relationship, and determine how it affects SUDEP risk.
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Affiliation(s)
- Rup K Sainju
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Deidre N Dragon
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Harold B Winnike
- Institute for Clinical and Translational Science, University of Iowa, Iowa City, IA, USA
| | - Patrick Ten Eyck
- Institute for Clinical and Translational Science, University of Iowa, Iowa City, IA, USA
| | - Mark A Granner
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Brian K Gehlbach
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - George B Richerson
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Veterans Affairs Medical Center, Iowa City, IA, USA
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28
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Marincovich A, Bravo E, Dlouhy B, Richerson GB. Amygdala lesions reduce seizure-induced respiratory arrest in DBA/1 mice. Epilepsy Behav 2021; 121:106440. [PMID: 31399338 PMCID: PMC7474464 DOI: 10.1016/j.yebeh.2019.07.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/06/2019] [Accepted: 07/13/2019] [Indexed: 10/26/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the most common cause of death in patients with refractory epilepsy. Human studies and animal models suggest that respiratory arrest is the initiating event leading to death in many cases of SUDEP. It has previously been reported that the onset of apnea can coincide with the spread of seizures to the amygdala, and apnea can be reproduced by electrical stimulation of the amygdala. The aim of the current work was to determine if the amygdala is required for seizure-induced respiratory arrest (S-IRA) in a mouse model of SUDEP. Experiments were performed on DBA/1 mice that have audiogenic seizures with a high incidence of fatal postictal respiratory arrest. Electrolytic lesions of the amygdala significantly reduced the incidence of S-IRA without altering seizures, baseline breathing, or the hypercapnic ventilatory response. These results indicate that the amygdala is a critical node in a pathway to the lower brainstem that is needed for seizures to cause respiratory arrest. SIGNIFICANCE STATEMENT: Sudden unexpected death in epilepsy is the most common cause of mortality in patients with refractory epilepsy, and S-IRA is thought to be important in the pathophysiology in many cases. In a patient with epilepsy, the onset of apnea has been shown to coincide with spread of seizures to the amygdala, and in multiple patients, apnea was induced by stimulation of the amygdala. Here, we show that lesions of the amygdala reduced the incidence of S-IRA and death in a mouse model of SUDEP. These results provide evidence that the amygdala may be a critical node in the pathway by which seizures influence the brainstem respiratory network to cause apnea. This article is part of the Special Issue NEWroscience 2018.
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Affiliation(s)
| | - Eduardo Bravo
- Department of Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - Brian Dlouhy
- Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
| | - George B. Richerson
- Department of Neurology, University of Iowa, Iowa City, IA 52242, USA,Department of Molecular Physiology & Biophysics, University of Iowa, Iowa City, IA 52242, USA,Neurology Service, Veterans Affairs Medical Center, Iowa City, IA 52242, USA
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29
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Akyüz E, Üner AK, Köklü B, Arulsamy A, Shaikh MF. Cardiorespiratory findings in epilepsy: A recent review on outcomes and pathophysiology. J Neurosci Res 2021; 99:2059-2073. [PMID: 34109651 DOI: 10.1002/jnr.24861] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/16/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022]
Abstract
Epilepsy is a debilitating disorder of uncontrollable recurrent seizures that occurs as a result of imbalances in the brain excitatory and inhibitory neuronal signals, that could stem from a range of functional and structural neuronal impairments. Globally, nearly 70 million people are negatively impacted by epilepsy and its comorbidities. One such comorbidity is the effect epilepsy has on the autonomic nervous system (ANS), which plays a role in the control of blood circulation, respiration and gastrointestinal function. These epilepsy-induced impairments in the circulatory and respiratory systems may contribute toward sudden unexpected death in epilepsy (SUDEP). Although, various hypotheses have been proposed regarding the role of epilepsy on ANS, the linking pathological mechanism still remains unclear. Channelopathies and seizure-induced damages in ANS-control brain structures were some of the causal/pathological candidates of cardiorespiratory comorbidities in epilepsy patients, especially in those who were drug resistant. However, emerging preclinical research suggest that neurotransmitter/receptor dysfunction and synaptic changes in the ANS may also contribute to the epilepsy-related autonomic disorders. Thus, pathological mechanisms of cardiorespiratory dysfunction should be elucidated by considering the modifications in anatomy and physiology of the autonomic system caused by seizures. In this regard, we present a comprehensive review of the current literature, both clinical and preclinical animal studies, on the cardiorespiratory findings in epilepsy and elucidate the possible pathological mechanisms of these findings, in hopes to prevent SUDEP especially in patients who are drug resistant.
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Affiliation(s)
- Enes Akyüz
- Department of Biophysics, Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Arda Kaan Üner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Betül Köklü
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Alina Arulsamy
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Mohd Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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30
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Wenker IC, Teran FA, Wengert ER, Wagley PK, Panchal PS, Blizzard EA, Saraf P, Wagnon JL, Goodkin HP, Meisler MH, Richerson GB, Patel MK. Postictal Death Is Associated with Tonic Phase Apnea in a Mouse Model of Sudden Unexpected Death in Epilepsy. Ann Neurol 2021; 89:1023-1035. [PMID: 33604927 DOI: 10.1002/ana.26053] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Sudden unexpected death in epilepsy (SUDEP) is an unpredictable and devastating comorbidity of epilepsy that is believed to be due to cardiorespiratory failure immediately after generalized convulsive seizures. METHODS We performed cardiorespiratory monitoring of seizure-induced death in mice carrying either a p.Arg1872Trp or p.Asn1768Asp mutation in a single Scn8a allele-mutations identified from patients who died from SUDEP-and of seizure-induced death in pentylenetetrazole-treated wild-type mice. RESULTS The primary cause of seizure-induced death for all mice was apnea, as (1) apnea began during a seizure and continued for tens of minutes until terminal asystole, and (2) death was prevented by mechanical ventilation. Fatal seizures always included a tonic phase that was coincident with apnea. This tonic phase apnea was not sufficient to produce death, as it also occurred during many nonfatal seizures; however, all seizures that were fatal had tonic phase apnea. We also made the novel observation that continuous tonic diaphragm contraction occurred during tonic phase apnea, which likely contributes to apnea by preventing exhalation, and this was only fatal when breathing did not resume after the tonic phase ended. Finally, recorded seizures from a patient with developmental epileptic encephalopathy with a previously undocumented SCN8A likely pathogenic variant (p.Leu257Val) revealed similarities to those of the mice, namely, an extended tonic phase that was accompanied by apnea. INTERPRETATION We conclude that apnea coincident with the tonic phase of a seizure, and subsequent failure to resume breathing, are the determining events that cause seizure-induced death in Scn8a mutant mice. ANN NEUROL 2021;89:1023-1035.
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Affiliation(s)
- Ian C Wenker
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA
| | - Frida A Teran
- Department of Neurology, University of Iowa, Iowa City, IA.,Medical Scientist Training Program, University of Iowa, Iowa City, IA.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA
| | - Eric R Wengert
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA.,Neuroscience Graduate Program, University of Virginia, Charlottesville, VA
| | - Pravin K Wagley
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA.,Department of Neurology, University of Virginia Health System, Charlottesville, VA
| | - Payal S Panchal
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA
| | - Elizabeth A Blizzard
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA
| | - Priyanka Saraf
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA
| | - Jacy L Wagnon
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Howard P Goodkin
- Department of Neurology, University of Virginia Health System, Charlottesville, VA
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - George B Richerson
- Department of Neurology, University of Iowa, Iowa City, IA.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA.,Veterans Affairs Medical Center, Iowa City, IA
| | - Manoj K Patel
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA
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31
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Ashraf O, Huynh T, Purnell BS, Murugan M, Fedele DE, Chitravanshi V, Boison D. Suppression of phrenic nerve activity as a potential predictor of imminent sudden unexpected death in epilepsy (SUDEP). Neuropharmacology 2021; 184:108405. [PMID: 33212114 PMCID: PMC8199795 DOI: 10.1016/j.neuropharm.2020.108405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/03/2020] [Accepted: 11/11/2020] [Indexed: 11/29/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a leading cause of death in patients with refractory epilepsy. Centrally-mediated respiratory dysfunction has been identified as one of the principal mechanisms responsible for SUDEP. Seizures generate a surge in adenosine release. Elevated adenosine levels suppress breathing. Insufficient metabolic clearance of a seizure-induced adenosine surge might be a precipitating factor in SUDEP. In order to deliver targeted therapies to prevent SUDEP, reliable biomarkers must be identified to enable prompt intervention. Because of the integral role of the phrenic nerve in breathing, we hypothesized that suppression of phrenic nerve activity could be utilized as predictive biomarker for imminent SUDEP. We used a rat model of kainic acid-induced seizures in combination with pharmacological suppression of metabolic adenosine clearance to trigger seizure-induced death in tracheostomized rats. Recordings of EEG, blood pressure, and phrenic nerve activity were made concomitant to the seizure. We found suppression of phrenic nerve burst frequency to 58.9% of baseline (p < 0.001, one-way ANOVA) which preceded seizure-induced death; importantly, irregularities of phrenic nerve activity were partly reversible by the adenosine receptor antagonist caffeine. Suppression of phrenic nerve activity may be a useful biomarker for imminent SUDEP. The ability to reliably detect the onset of SUDEP may be instrumental in the timely administration of potentially lifesaving interventions.
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Affiliation(s)
- Omar Ashraf
- Department of Neurosurgery, Robert Wood Johnson and New Jersey Medical Schools, Rutgers University, Piscataway, NJ, 08854, USA
| | - Trong Huynh
- Department of Neurosurgery, Robert Wood Johnson and New Jersey Medical Schools, Rutgers University, Piscataway, NJ, 08854, USA
| | - Benton S Purnell
- Department of Neurosurgery, Robert Wood Johnson and New Jersey Medical Schools, Rutgers University, Piscataway, NJ, 08854, USA; Department of Neurology, University of Iowa, Iowa City, IA, 52242, USA
| | - Madhuvika Murugan
- Department of Neurosurgery, Robert Wood Johnson and New Jersey Medical Schools, Rutgers University, Piscataway, NJ, 08854, USA
| | - Denise E Fedele
- Department of Neurosurgery, Robert Wood Johnson and New Jersey Medical Schools, Rutgers University, Piscataway, NJ, 08854, USA
| | - Vineet Chitravanshi
- Department of Neurosurgery, Robert Wood Johnson and New Jersey Medical Schools, Rutgers University, Piscataway, NJ, 08854, USA
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson and New Jersey Medical Schools, Rutgers University, Piscataway, NJ, 08854, USA; Brain Health Institute, Rutgers University, Piscataway, NJ, 08854, USA; Rutgers Neurosurgery H.O.P.E. Center, Department of Neurosurgery, Rutgers University, New Brunswick, NJ, 08901, USA.
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32
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Tescarollo FC, Rombo DM, DeLiberto LK, Fedele DE, Alharfoush E, Tomé ÂR, Cunha RA, Sebastião AM, Boison D. Role of Adenosine in Epilepsy and Seizures. J Caffeine Adenosine Res 2020; 10:45-60. [PMID: 32566903 PMCID: PMC7301316 DOI: 10.1089/caff.2019.0022] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Adenosine is an endogenous anticonvulsant and neuroprotectant of the brain. Seizure activity produces large quantities of adenosine, and it is this seizure-induced adenosine surge that normally stops a seizure. However, within the context of epilepsy, adenosine plays a wide spectrum of different roles. It not only controls seizures (ictogenesis), but also plays a major role in processes that turn a normal brain into an epileptic brain (epileptogenesis). It is involved in the control of abnormal synaptic plasticity and neurodegeneration and plays a major role in the expression of comorbid symptoms and complications of epilepsy, such as sudden unexpected death in epilepsy (SUDEP). Given the important role of adenosine in epilepsy, therapeutic strategies are in development with the goal to utilize adenosine augmentation not only for the suppression of seizures but also for disease modification and epilepsy prevention, as well as strategies to block adenosine A2A receptor overfunction associated with neurodegeneration. This review provides a comprehensive overview of the role of adenosine in epilepsy.
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Affiliation(s)
- Fabio C. Tescarollo
- Deptartment of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Diogo M. Rombo
- Faculty of Medicine, Institute of Pharmacology and Neurosciences, Lisbon, Portugal
- Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Lindsay K. DeLiberto
- Deptartment of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Denise E. Fedele
- Deptartment of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Enmar Alharfoush
- Deptartment of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Ângelo R. Tomé
- Faculty of Science and Technology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Rodrigo A. Cunha
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Ana M. Sebastião
- Faculty of Medicine, Institute of Pharmacology and Neurosciences, Lisbon, Portugal
- Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Detlev Boison
- Deptartment of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
- Department of Neurosurgery, New Jersey Medical School, Rutgers University, Piscataway, New Jersey, USA
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33
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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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Kuo FS, Cleary CM, LoTurco JJ, Chen X, Mulkey DK. Disordered breathing in a mouse model of Dravet syndrome. eLife 2019; 8:e43387. [PMID: 31025941 PMCID: PMC6506208 DOI: 10.7554/elife.43387] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 04/25/2019] [Indexed: 12/11/2022] Open
Abstract
Dravet syndrome (DS) is a form of epilepsy with a high incidence of sudden unexpected death in epilepsy (SUDEP). Respiratory failure is a leading cause of SUDEP, and DS patients' frequently exhibit disordered breathing. Despite this, mechanisms underlying respiratory dysfunction in DS are unknown. We found that mice expressing a DS-associated Scn1a missense mutation (A1783V) conditionally in inhibitory neurons (Slc32a1cre/+::Scn1aA1783V fl/+; defined as Scn1aΔE26) exhibit spontaneous seizures, die prematurely and present a respiratory phenotype including hypoventilation, apnea, and a diminished ventilatory response to CO2. At the cellular level in the retrotrapezoid nucleus (RTN), we found inhibitory neurons expressing the Scn1a A1783V variant are less excitable, whereas glutamatergic chemosensitive RTN neurons, which are a key source of the CO2/H+-dependent drive to breathe, are hyper-excitable in slices from Scn1aΔE26 mice. These results show loss of Scn1a function can disrupt respiratory control at the cellular and whole animal levels.
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Affiliation(s)
- Fu-Shan Kuo
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsUnited States
| | - Colin M Cleary
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsUnited States
| | - Joseph J LoTurco
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsUnited States
| | - Xinnian Chen
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsUnited States
| | - Daniel K Mulkey
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsUnited States
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