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Potemkina EG, Salomatina TA, Andreev EV, Abramov KB, Bannikova VD, Dengina NO, Nezdorovina VG, Zabrodskaya YM, Samochernykh KA, Odintsova GV. [MR morphometry in epileptology: progress and perspectives]. ZHURNAL VOPROSY NEIROKHIRURGII IMENI N. N. BURDENKO 2023; 87:113-119. [PMID: 37325834 DOI: 10.17116/neiro202387031113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Morphometric MRI analysis improves neuroimaging of structural changes in epilepsy. OBJECTIVE To investigate diagnostic potential of MR brain morphometry in neurosurgical epileptology. MATERIAL AND METHODS An interdisciplinary working group reviewed the studies devoted to MR morphometry in epileptology as a part of state assignment No. 056-00119-22-00. Study subject was trials of MR-morphometry in epilepsy. Searching for literature data was conducted in international and national databases between 2017 and 2022 using certain keywords. Final analysis included 36 publications. RESULTS Currently, MR brain morphometry allows measurement of cortical volume and thickness, surface area and depth of furrows, as well as analysis of cortical tortuosity and fractal changes. In neurosurgical epileptology, MR-morphometry has the greatest diagnostic value in MR-negative epilepsy. This method simplifies preoperative diagnosis and reduces costs. CONCLUSION Morphometry in neurosurgical epileptology is an additional method for verifying the epileptogenic zone. Automated programs simplify application of this method.
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Affiliation(s)
- E G Potemkina
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - T A Salomatina
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - E V Andreev
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - K B Abramov
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - V D Bannikova
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - N O Dengina
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - V G Nezdorovina
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - Yu M Zabrodskaya
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - K A Samochernykh
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
| | - G V Odintsova
- Almazov National Medical Research Centre, Polenov Neurosurgery Research Institute, St. Petersburg, Russia
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Zhang Q, Suller-Marti A, Ding JJ, Deng G, He W, Burneo JG, Hammond RR, Ang LC. Epilepsy-associated death in the Southwestern Ontario: A clinicopathological correlation study. Brain Pathol 2022; 33:e13121. [PMID: 36180818 PMCID: PMC10041075 DOI: 10.1111/bpa.13121] [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: 04/24/2022] [Accepted: 09/13/2022] [Indexed: 11/30/2022] Open
Abstract
Patients with epilepsy are at elevated risk for premature mortality, of which sudden unexpected death in epilepsy (SUDEP) is one of the leading causes. SUDEP incidence varies significantly depending on the population and the methods used to document the cause of death. We performed retrospective case review at the London Health Sciences Centre for the period of 2000 to 2018. Clinical information, scene investigations, general pathology findings, toxicology, and neuropathology findings were obtained, examined, and confirmed by two neuropathologists and one epileptologist. The characteristics were compared and summarized. We also evaluated the impact of 2010 revision of Ontario Coroner Act Regulation, which significantly limited whole brain examination. Among the 12,206 cases reviewed, we identified 152 cases with a known history of epilepsy. Ninety-seven cases (64%) were classified as SUDEP. There were significantly more SUDEP decedents found dead unwitnessed at night in prone position, than non-SUDEP. Generalized seizures were strongly associated with SUDEP. A male predominance was observed in SUDEP group between 15 and 35 years old. Near half of the brains examined were "unremarkable." There was no difference in neuropathology findings between SUDEP and non-SUDEP groups. After implementation of the 2010 revision of Ontario Coroner Act Regulation, fixed whole brain examination was reduced from 88% to 7% of the epilepsy-related death investigation. Except a lower diagnosis rate of "inflammatory/infectious changes," there were no significant differences in neuropathology findings. This is the first detailed clinical-pathological study on epilepsy-related death based on a Canadian cohort. This study reinforces the previously reported findings in SUDEP and highlights the importance of clinicopathological correlation for accurate classification of epilepsy-related death.
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Affiliation(s)
- Qi Zhang
- Department of Pathology and Lab Medicine, London Health Sciences Centre, Western University, London, Ontario, Canada.,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Ana Suller-Marti
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.,Department of Pediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.,Department of Psychiatry, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Jane Jian Ding
- Department of Pathology and Lab Medicine, London Health Sciences Centre, Western University, London, Ontario, Canada
| | - Gansen Deng
- Department of Statistical and Actuarial Sciences, Western University, London, Ontario, Canada
| | - Wenqing He
- Department of Statistical and Actuarial Sciences, Western University, London, Ontario, Canada
| | - Jorge G Burneo
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.,Neuroepidemiology Unit, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Robert R Hammond
- Department of Pathology and Lab Medicine, London Health Sciences Centre, Western University, London, Ontario, Canada.,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Lee-Cyn Ang
- Department of Pathology and Lab Medicine, London Health Sciences Centre, Western University, London, Ontario, Canada.,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
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3
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Zhou Z, Li K, Chu Y, Li C, Zhang T, Liu P, Sun T, Jiang C. ROS-removing nano-medicine for navigating inflammatory microenvironment to enhance anti-epileptic therapy. Acta Pharm Sin B 2022; 13:1246-1261. [PMID: 36970212 PMCID: PMC10031259 DOI: 10.1016/j.apsb.2022.09.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/29/2022] [Accepted: 09/15/2022] [Indexed: 11/01/2022] Open
Abstract
As a neurological disorder in the brain, epilepsy is not only associated with abnormal synchronized discharging of neurons, but also inseparable from non-neuronal elements in the altered microenvironment. Anti-epileptic drugs (AEDs) merely focusing on neuronal circuits frequently turn out deficient, which is necessitating comprehensive strategies of medications to cover over-exciting neurons, activated glial cells, oxidative stress and chronic inflammation synchronously. Therefore, we would report the design of a polymeric micelle drug delivery system that was functioned with brain targeting and cerebral microenvironment modulation. In brief, reactive oxygen species (ROS)-sensitive phenylboronic ester was conjugated with poly-ethylene glycol (PEG) to form amphiphilic copolymers. Additionally, dehydroascorbic acid (DHAA), an analogue of glucose, was applied to target glucose transporter 1 (GLUT1) and facilitate micelle penetration across the blood‒brain barrier (BBB). A classic hydrophobic AED, lamotrigine (LTG), was encapsulated in the micelles via self-assembly. When administrated and transferred across the BBB, ROS-scavenging polymers were expected to integrate anti-oxidation, anti-inflammation and neuro-electric modulation into one strategy. Moreover, micelles would alter LTG distribution in vivo with improved efficacy. Overall, the combined anti-epileptic therapy might provide effective opinions on how to maximize neuroprotection during early epileptogenesis.
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Li YL, Wu JJ, Ma J, Li SS, Xue X, Wei D, Shan CL, Zheng MX, Hua XY, Xu JG. Brain Structural Changes in Carpal Tunnel Syndrome Patients: From the Perspectives of Structural Connectivity and Structural Covariance Network. Neurosurgery 2021; 89:978-986. [PMID: 34634107 DOI: 10.1093/neuros/nyab335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 07/16/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Carpal tunnel syndrome (CTS) is a common peripheral entrapment neuropathy. However, CTS-related changes of brain structural covariance and structural covariance networks (SCNs) patterns have not been clearly studied. OBJECTIVE To explore CTS-related brain changes from perspectives of structural connectivity and SCNs. METHODS Brain structural magnetic resonance images were acquired from 27 CTS patients and 19 healthy controls (HCs). Structural covariance and SCNs were constructed based on gray matter volume. The global network properties including clustering coefficient (Cp), characteristic path length (Lp), small-worldness index, global efficiency (Eglob), and local efficiency (Eloc) and regional network properties including degree, betweenness centrality (BC), and Eloc of a given node were calculated with graph theoretical analysis. RESULTS Compared with HCs, the strength of structural connectivity between the dorsal anterior insula and medial prefrontal thalamus decreased (P < .001) in CTS patients. There was no intergroup difference of area under the curve for Cp, Lp¸ Eglob, and Eloc (all P > .05). The real-world SCN of CTS patients showed a small-world topology ranging from 2% to 32%. CTS patients showed lower nodal degrees of the dorsal anterior insula and medial prefrontal thalamus, and higher Eloc of a given node and BC in the lateral occipital cortex (P < .001) and the dorsolateral middle temporal gyrus (P < .001) than HCs, respectively. CONCLUSION CTS had a profound impact on brain structures from perspectives of structural connectivity and SCNs.
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Affiliation(s)
- Yu-Lin Li
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jia-Jia Wu
- Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jie Ma
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Si-Si Li
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xin Xue
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Dong Wei
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Chun-Lei Shan
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Engineering Research Center, Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai, China
| | - Mou-Xiong Zheng
- Department of Traumatology and Orthopedics, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xu-Yun Hua
- Department of Traumatology and Orthopedics, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jian-Guang Xu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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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: 6] [Impact Index Per Article: 2.0] [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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Somani A, El-Hachami H, Patodia S, Sisodiya S, Thom M. Regional microglial populations in central autonomic brain regions in SUDEP. Epilepsia 2021; 62:1318-1328. [PMID: 33942290 DOI: 10.1111/epi.16904] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Sudden unexpected death in epilepsy (SUDEP) may arise as a result of autonomic dysfunction during a seizure. The central autonomic networks (CANs) modulate brainstem cardiorespiratory regulation. Recent magnetic resonance imaging (MRI) studies in SUDEP have shown cortical and subcortical volume changes and altered connectivity between CAN regions, but the pathological correlate is unknown. Because neuroinflammation is both a cause and a consequence of seizures and may relate to regional brain pathology, our aim was to evaluate microglial populations in CANs in SUDEP. METHODS In 55 postmortem cases, including SUDEP, epilepsy controls without SUDEP and nonepilepsy controls, we quantified Iba1-expressing microglia in 14 cortical and thalamic areas that included known CAN regions. RESULTS Mean Iba1 labeling across all brain regions was significantly higher in SUDEP cases compared to epilepsy and nonepilepsy controls. There was significant regional variation in Iba1 labeling in SUDEP cases only, with highest labeling in the medial thalamus. Significantly higher labeling in SUDEP cases than epilepsy and nonepilepsy controls was consistently noted in the superior temporal gyrus. In cases with documented seizures up to 10 days prior to death, significantly higher mean Iba1 labeling was observed in SUDEP compared to epilepsy controls. SIGNIFICANCE Our findings support microglial activation in SUDEP, including cortical and subcortical regions with known autonomic functions such as the thalamus and superior temporal gyrus. This may be relevant to cellular pathomechanisms underlying cardioregulatory failure during a seizure.
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Affiliation(s)
- Alyma Somani
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Hanna El-Hachami
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Smriti Patodia
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Sanjay Sisodiya
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
| | - Maria Thom
- Departments of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Neuropathology, National Hospital for Neurology and Neurosurgery Queen Square, London, UK
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McGuone D, Crandall LG, Devinsky O. Sudden Unexplained Death in Childhood: A Neuropathology Review. Front Neurol 2020; 11:582051. [PMID: 33178125 PMCID: PMC7596260 DOI: 10.3389/fneur.2020.582051] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/09/2020] [Indexed: 12/11/2022] Open
Abstract
Sudden Unexplained Death in Childhood (SUDC) is the unexpected death of a child over age 12 months that remains unexplained after a thorough case investigation, including review of the child's medical history, circumstances of death, a complete autopsy and ancillary testing (1). First defined in 2005, SUDC cases are more often male, with death occurring during a sleep period, being found prone, peak winter incidence, associated with febrile seizure history in ~28% of cases and mild pathologic changes insufficient to explain the death (1, 2). There has been little progress in understanding the causes of SUDC and no progress in prevention. Despite reductions in sudden unexpected infant death (SUID) and other causes of mortality in childhood, the rate of SUDC has increased during the past two decades (3-5). In Ireland, SUID deaths were cut in half from 1994 to 2008 while SUDC deaths more than doubled (4). Surveillance issues, including lack of standardized certification practices, affect our understanding of the true magnitude of unexplained child deaths. Mechanisms underlying SUDC, like SUID, remain largely speculative. Limited and inconsistent evidence implicates abnormalities in brainstem autonomic and serotonergic nuclei, critical for arousal, cardiorespiratory control, and reflex responses to life-threatening hypoxia or hypercarbia in sleep (6). Abnormalities in medullary serotonergic neurons and receptors, as well as cardiorespiratory brainstem nuclei occur in some SUID cases, but have never been studied in SUDC. Retrospective, small SUDC studies with non-standardized methodologies most often demonstrate minor hippocampal abnormalities, as well as focal cortical dysplasia and dysgenesis of the brainstem and cerebellum. The significance of these findings to SUDC pathogenesis remains unclear with some investigators and forensic pathologists labeling these findings as normal variants, or potential causes of SUDC. The development of preventive strategies will require a greater understanding of underlying mechanisms.
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Affiliation(s)
- Declan McGuone
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | - Laura G Crandall
- Comprehensive Epilepsy Center, New York University School of Medicine, New York, NY, United States.,SUDC Foundation, Herndon, VA, United States
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, New York University School of Medicine, New York, NY, United States
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Kon FC, Vázquez RZ, Lang A, Cohen MC. Hippocampal abnormalities and seizures: a 16-year single center review of sudden unexpected death in childhood, sudden unexpected death in epilepsy and SIDS. Forensic Sci Med Pathol 2020; 16:423-434. [PMID: 32712908 DOI: 10.1007/s12024-020-00268-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2020] [Indexed: 12/27/2022]
Abstract
Sudden Unexpected Death in Childhood (SUDC) is the unexplained death of children aged between 1 and 18 years old. Hippocampal abnormalities have previously been described in Sudden Unexpected Death in Epilepsy (SUDEP) and it is possible that SUDC shares similar pathogenic mechanisms with SUDEP. Our aim was to determine the prevalence of hippocampal abnormalities, history of seizures and demographic features in our caseload of SUDC, SUDEP and SIDS cases. A review of post-mortem reports from 2003 to 2018 was carried out to identify cases of SUDC, SUDEP and SIDS. Histological evidence of hippocampal abnormalities, patient demographics (age, gender), sleeping position, and past medical history (history of seizures and illness 72 hours prior to death) were recorded. Statistical analysis was performed to compare the three groups. 48 SUDC, 18 SUDEP and 358 SIDS cases were identified. Hippocampal abnormalities associated with temporal lobe epilepsy were found in 44.4% of SUDC cases. 5/15 SUDC cases with a history of seizures demonstrated hippocampal abnormalities. SUDC cases were also more likely to be found prone compared to SIDS cases. In comparison with SIDS, both SUDC and SUDEP cases were more likely to demonstrate hippocampal abnormalities (SUDC: (OR = 9.4, 95% CI: 3.1-29.1, p < 0.001; SUDEP: OR = 35.4, 95% CI: 8.3-151.5, p < 0.001). We found a potential link between hippocampal abnormalities and epileptic seizures in SUDC. A concerted effort should be directed towards consistent sampling and standardized description of the hippocampus and clinical correlation with a history of seizures/epilepsy in postmortem reports.
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Affiliation(s)
- Fu Chuen Kon
- Histopathology Department, Sheffield Children's Hospital NHS FT, Sheffield, UK.,Medical School, University of Sheffield, Sheffield, UK
| | | | - Andrew Lang
- Histopathology Department, Sheffield Children's Hospital NHS FT, Sheffield, UK
| | - Marta C Cohen
- Histopathology Department, Sheffield Children's Hospital NHS FT, Sheffield, UK. .,Department of Oncology & Metabolism, University of Sheffield, Sheffield, UK.
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Roy A, Millen KJ, Kapur RP. Hippocampal granule cell dispersion: a non-specific finding in pediatric patients with no history of seizures. Acta Neuropathol Commun 2020; 8:54. [PMID: 32317027 PMCID: PMC7171777 DOI: 10.1186/s40478-020-00928-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/03/2020] [Indexed: 12/13/2022] Open
Abstract
Chronic epilepsy has been associated with hippocampal abnormalities like neuronal loss, gliosis and granule cell dispersion. The granule cell layer of a normal human hippocampal dentate gyrus is traditionally regarded as a compact neuron-dense layer. Histopathological studies of surgically resected or autopsied hippocampal samples primarily from temporal lobe epilepsy patients, as well as animal models of epilepsy, describe variable patterns of granule cell dispersion including focal cell clusters, broader thick segments, and bilamination or “tram-tracking”. Although most studies have implicated granule cell dispersion as a specific feature of chronic epilepsy, very few “non-seizure” controls were included in these published investigations. Our retrospective survey of 147 cadaveric pediatric human hippocampi identified identical morphological spectra of granule cell dispersion in both normal and seizure-affected brains. Moreover, sections across the entire antero-posterior axis of a control cadaveric hippocampus revealed repetitive occurrence of different morphologies of the granule cell layer – compact, focally disaggregated and bilaminar. The results indicate that granule cell dispersion is within the spectrum of normal variation and not unique to patients with epilepsy. We speculate that sampling bias has been responsible for an erroneous dogma, which we hope to rectify with this investigation.
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