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Lam HW, Patodia S, Zeicu C, Lim YM, Mrzyglod A, Scott C, Oliveira J, De Tisi J, Legouhy A, Zhang H, Koepp M, Diehl B, Thom M. Quantitative cellular pathology of the amygdala in temporal lobe epilepsy and correlation with magnetic resonance imaging volumetry, tissue microstructure, and sudden unexpected death in epilepsy risk factors. Epilepsia 2024; 65:2368-2385. [PMID: 38837385 DOI: 10.1111/epi.18033] [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: 02/19/2024] [Revised: 05/18/2024] [Accepted: 05/20/2024] [Indexed: 06/07/2024]
Abstract
OBJECTIVE Amygdala enlargement can occur in temporal lobe epilepsy, and increased amygdala volume is also reported in sudden unexpected death in epilepsy (SUDEP). Apnea can be induced by amygdala stimulation, and postconvulsive central apnea (PCCA) and generalized seizures are both known SUDEP risk factors. Neurite orientation dispersion and density imaging (NODDI) has recently provided additional information on altered amygdala microstructure in SUDEP. In a series of 24 surgical temporal lobe epilepsy cases, our aim was to quantify amygdala cellular pathology parameters that could predict enlargement, NODDI changes, and ictal respiratory dysfunction. METHODS Using whole slide scanning automated quantitative image analysis methods, parallel evaluation of myelin, axons, dendrites, oligodendroglia, microglia, astroglia, neurons, serotonergic networks, mTOR-pathway activation (pS6) and phosphorylated tau (pTau; AT8, AT100, PHF) in amygdala, periamygdala cortex, and white matter regions of interest were compared with preoperative magnetic resonance imaging data on amygdala size, and in 13 cases with NODDI and evidence of ictal-associated apnea. RESULTS We observed significantly higher glial labeling (Iba1, glial fibrillary acidic protein, Olig2) in amygdala regions compared to cortex and a strong positive correlation between Olig2 and Iba1 in the amygdala. Larger amygdala volumes correlated with lower microtubule-associated protein (MAP2), whereas higher NODDI orientation dispersion index correlated with lower Olig2 cell densities. In the three cases with recorded PCCA, higher MAP2 and pS6-235 expression was noted than in those without. pTau did not correlate with SUDEP risk factors, including seizure frequency. SIGNIFICANCE Histological quantitation of amygdala microstructure can shed light on enlargement and diffusion imaging alterations in epilepsy to explore possible mechanisms of amygdala dysfunction, including mTOR pathway activation, that in turn may increase the risk for SUDEP.
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Affiliation(s)
- Hou Wang Lam
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Smriti Patodia
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Claudia Zeicu
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Yau Mun Lim
- Division of Neuropathology, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
| | - Alicja Mrzyglod
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Catherine Scott
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
| | - Joana Oliveira
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
| | - Jane De Tisi
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Antoine Legouhy
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
| | - Hui Zhang
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
| | - Matthias Koepp
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Queen Square Institute of Neurology, London, UK
- Division of Neuropathology, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Foundation Trust, London, UK
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Zhao C, Tang Y, Xiao Y, Jiang P, Zhang Z, Gong Q, Zhou D. Asymmetrical cortical surface area decrease in epilepsy patients with postictal generalized electroencephalography suppression. Cereb Cortex 2024; 34:bhae026. [PMID: 38342683 DOI: 10.1093/cercor/bhae026] [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: 11/09/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 02/13/2024] Open
Abstract
Postictal generalized electroencephalographic suppression is a possible electroencephalographic marker for sudden unexpected death in epilepsy. We aimed to investigate the cortical surface area abnormalities in epilepsy patients with postictal generalized electroencephalographic suppression. We retrospectively included 30 epilepsy patients with postictal generalized electroencephalographic suppression (PGES+), 21 epilepsy patients without postictal generalized electroencephalographic suppression (PGES-), and 30 healthy controls. Surface-based analysis on high-resolution T1-weighted images was conducted and cortical surface areas were compared among the three groups, alongside correlation analyses with seizure-related clinical variables. Compared with PGES- group, we identified reduced surface area in the bilateral insula with more extensive distribution in the right hemisphere in PGES+ group. The reduced right insular surface area was associated with younger seizure-onset age. When compared with healthy controls, PGES- group presented reduced surface area in the left caudal middle frontal gyrus; PGES+ group presented more widespread surface area reductions in the right posterior cingulate gyrus, left postcentral gyrus, middle frontal gyrus, and middle temporal gyrus. Our results suggested cortical microstructural impairment in patients with postictal generalized electroencephalographic suppression. The significant surface area reductions in the insular cortex supported the autonomic network involvement in the pathology of postictal generalized electroencephalographic suppression, and its right-sided predominance suggested the potential shared abnormal brain network for postictal generalized electroencephalographic suppression and sudden unexpected death in epilepsy.
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Affiliation(s)
- Chenyang Zhao
- Department of Neurology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Yingying Tang
- Department of Neurology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
| | - Yuan Xiao
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
| | - Ping Jiang
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
- West China Medical Publishers, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu 610041, Sichuan, China
| | - Ziyi Zhang
- West China School of Public Health, Sichuan University, Chengdu 610041, Sichuan, China
| | - Qiyong Gong
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu 610041, Sichuan, China
| | - Dong Zhou
- Department of Neurology, West China Hospital of Sichuan University, Chengdu 610041, Sichuan, China
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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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Buerki SE, Haas C, Neubauer J. Exome analysis focusing on epilepsy-related genes in children and adults with sudden unexplained death. Seizure 2023; 113:66-75. [PMID: 37995443 DOI: 10.1016/j.seizure.2023.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/25/2023] Open
Abstract
PURPOSE Genetic studies in sudden infant death syndrome (SIDS) and sudden unexplained death (SUD) cohorts have indicated that cardiovascular diseases might have contributed to sudden unexpected death in 20-35 % of autopsy-negative cases. Sudden unexpected death can also occur in people with epilepsy, termed as sudden unexpected death in epilepsy (SUDEP). The pathophysiological mechanisms of SUDEP are not well understood, but are likely multifactorial, including seizure-induced hypoventilation and arrhythmias as well as genetic risk factors. The sudden death of some of the SIDS/SUD victims might also be explained by genetic epilepsy, therefore this study aimed to expand the post-mortem genetic analysis of SIDS/SUD cases to epilepsy-related genes. METHODS Existing whole-exome sequencing data from our 155 SIDS and 45 SUD cases were analyzed, with a focus on 365 epilepsy-related genes. Nine of the SUD victims had a known medical history of epilepsy, seizures or other underlying neurological conditions and were therefore classified as SUDEP cases. RESULTS In our SIDS and SUD cohorts, we found epilepsy-related pathogenic/likely pathogenic variants in the genes OPA1, RAI1, SCN3A, SCN5A and TSC2. CONCLUSION Post-mortem analysis of epilepsy-related genes identified potentially disease-causing variants that might have contributed to the sudden death events in our SIDS/SUD cases. However, the interpretation of identified variants remains challenging and often changes over time as more data is gathered. Overall, this study contributes insight in potentially pathophysiological epilepsy-related mechanisms in SIDS, SUD and SUDEP victims and underlines the importance of sensible counselling on the risk and preventive measures in genetic epilepsy.
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Affiliation(s)
- Sarah E Buerki
- Department of Neuropediatrics, University Children's Hospital Zurich, Switzerland
| | - Cordula Haas
- Zurich Institute of Forensic Medicine, University of Zurich, Switzerland.
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Argo A, Puntarello M, Malta G, Buscemi R, Scalzo G, Triolo V, Albano GD, Zerbo S. The analysis of SUDEP forensic autopsies leading to preventable events. Front Neurol 2023; 14:1231515. [PMID: 37456625 PMCID: PMC10346851 DOI: 10.3389/fneur.2023.1231515] [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: 05/30/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023] Open
Abstract
Introduction The diagnosis of unexpected death by excluding non-natural causes, particularly in subjects with epilepsy, is a topic of interest and it is difficult to identify in the forensic field. Health professionals sometimes are faced with cases of sudden death, generally in young adults with a long history of epilepsy that require, for judicial purposes, an explanation in terms of cause and means to determine the death. SUDEP is an entity diagnosed by the exclusion of other causes that may have led to death, and then for forensic purposes, it requires particular attention and knowledge, and there is difficulty in identifying it. Our contribution aims to illustrate the scientific community pathological findings, medical history, and circumstantial evidence of four cases of sudden death in epileptic subjects. Method We illustrated four cases of judicial autopsies from the Institute of Forensic Medicine of Palermo, Italy; the purpose was to exclude the criminal intervention in determining the death as non-natural. The study of victims' medical history, the toxicological investigations, and the autopsy findings analyzed both from macroscopic and microscopic aspects have made it possible to highlight some findings that can be traced back to SUDEP despite the small sample of subjects studied. Results These presented findings of four SUDEP cases could help forensic pathologists in recognizing this entity, by highlighting its characteristics, and allowing for a pathological classification, also in relation to the use of drugs for epilepsy treatment and circumstances of death. Discussion To obtain a definite diagnosis of SUDEP, a complex investigation process is required in a multidisciplinary approach. Considering the literature review with criticism, it could allow health professionals to select the characteristics of epileptic patients at risk of sudden death. Processing human behaviors, molecular and histopathological findings of the autopsies, but also the physiological, and pathological human body system functions thanks to Artificial Intelligence, could be the key to explaining SUDEP mechanisms and the future results to prevent it.
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Affiliation(s)
- Antonina Argo
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Section of Legal Medicine, University of Palermo, Palermo, Italy
| | - Maria Puntarello
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Section of Legal Medicine, University of Palermo, Palermo, Italy
| | - Ginevra Malta
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Section of Legal Medicine, University of Palermo, Palermo, Italy
| | - Roberto Buscemi
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Section of Legal Medicine, University of Palermo, Palermo, Italy
| | - Giovanni Scalzo
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Section of Legal Medicine, University of Palermo, Palermo, Italy
| | | | - Giuseppe Davide Albano
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Section of Legal Medicine, University of Palermo, Palermo, Italy
| | - Stefania Zerbo
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Section of Legal Medicine, University of Palermo, Palermo, Italy
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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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