1
|
Li J, Qi H, Chen Y, Zhu X. Epilepsy and demyelination: Towards a bidirectional relationship. Prog Neurobiol 2024; 234:102588. [PMID: 38378072 DOI: 10.1016/j.pneurobio.2024.102588] [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: 01/14/2024] [Accepted: 02/13/2024] [Indexed: 02/22/2024]
Abstract
Demyelination stands out as a prominent feature in individuals with specific types of epilepsy. Concurrently, individuals with demyelinating diseases, such as multiple sclerosis (MS) are at a greater risk of developing epilepsy compared to non-MS individuals. These bidirectional connections raise the question of whether both pathological conditions share common pathogenic mechanisms. This review focuses on the reciprocal relationship between epilepsy and demyelination diseases. We commence with an overview of the neurological basis of epilepsy and demyelination diseases, followed by an exploration of how our comprehension of these two disorders has evolved in tandem. Additionally, we discuss the potential pathogenic mechanisms contributing to the interactive relationship between these two diseases. A more nuanced understanding of the interplay between epilepsy and demyelination diseases has the potential to unveiling the molecular intricacies of their pathological relationships, paving the way for innovative directions in future clinical management and treatment strategies for these diseases.
Collapse
Affiliation(s)
- Jiayi Li
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China; Clinical Medicine, Medical School of Southeast University, Nanjing, China
| | - Honggang Qi
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China
| | - Yuzhou Chen
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China; Clinical Medicine, Medical School of Southeast University, Nanjing, China
| | - Xinjian Zhu
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China.
| |
Collapse
|
2
|
Abstract
Within the past decade, multiple lines of evidence have converged to identify a critical role for activity-regulated myelination in tuning the function of neural networks. In this Review, we provide an overview of accumulating evidence that activity-regulated myelination is required for brain adaptation and learning across multiple domains. We then discuss dysregulation of activity-dependent myelination in the context of neurological disease, a novel frontier with the potential to uncover new mechanisms of disease pathogenesis and to develop new therapeutic strategies. Alterations in myelination and neural network function can result from deficient myelin plasticity that impairs neurological function or from maladaptive myelination, in which intact activity-dependent myelination contributes to the disease process by promoting pathological patterns of neuronal activity. These emerging mechanisms suggest new avenues for therapeutic intervention that could more fully address the complex interactions between neurons and oligodendroglia.
Collapse
|
3
|
Miralles R, Patel MK. That's a Wrap: Could Controlling Activity-Regulated Myelination Prevent Absence Seizures? Epilepsy Curr 2022; 22:395-397. [PMID: 36426188 PMCID: PMC9661616 DOI: 10.1177/15357597221123898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2024] Open
Abstract
Maladaptive Myelination Promotes Generalized Epilepsy Progression Knowles JK, Xu H, Soane C, Batra A, Saucedo T, Frost E, Tam LT, Fraga D, Ni L, Villar K, Talmi S, Huguenard JR, Monje M. Nat Neurosci . 2022;25(5):596-606. doi:10.1038/s41593-022-01052-2 Activity-dependent myelination can fine-tune neural network dynamics. Conversely, aberrant neuronal activity, as occurs in disorders of recurrent seizures (epilepsy), could promote maladaptive myelination, contributing to pathogenesis. In this study, we tested the hypothesis that activity-dependent myelination resulting from absence seizures, which manifest as frequent behavioral arrests with generalized electroencephalography (EEG) spike-wave discharges, promote thalamocortical network hypersynchrony and contribute to epilepsy progression. We found increased oligodendrogenesis and myelination specifically within the seizure network in two models of generalized epilepsy with absence seizures (Wag/Rij rats and Scn8a+/mut mice), evident only after epilepsy onset. Aberrant myelination was prevented by pharmacological seizure inhibition in Wag/Rij rats. Blocking activity-dependent myelination decreased seizure burden over time and reduced ictal synchrony as assessed by EEG coherence. These findings indicate that activity-dependent myelination driven by absence seizures contributes to epilepsy progression; maladaptive myelination may be pathogenic in some forms of epilepsy and other neurological diseases.
Collapse
Affiliation(s)
- Raquel Miralles
- University of Virginia Health System Ringgold Standard Institution-Anesthesiology, Charlottesville, VA, USA
| | - Manoj K Patel
- University of Virginia Health System Ringgold Standard Institution-Anesthesiology, Charlottesville, VA, USA
| |
Collapse
|
4
|
Knowles JK, Xu H, Soane C, Batra A, Saucedo T, Frost E, Tam LT, Fraga D, Ni L, Villar K, Talmi S, Huguenard JR, Monje M. Maladaptive myelination promotes generalized epilepsy progression. Nat Neurosci 2022; 25:596-606. [PMID: 35501379 PMCID: PMC9076538 DOI: 10.1038/s41593-022-01052-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 03/14/2022] [Indexed: 12/18/2022]
Abstract
Activity-dependent myelination can fine-tune neural network dynamics. Conversely, aberrant neuronal activity, as occurs in disorders of recurrent seizures (epilepsy), could promote maladaptive myelination, contributing to pathogenesis. In this study, we tested the hypothesis that activity-dependent myelination resulting from absence seizures, which manifest as frequent behavioral arrests with generalized electroencephalography (EEG) spike-wave discharges, promote thalamocortical network hypersynchrony and contribute to epilepsy progression. We found increased oligodendrogenesis and myelination specifically within the seizure network in two models of generalized epilepsy with absence seizures (Wag/Rij rats and Scn8a+/mut mice), evident only after epilepsy onset. Aberrant myelination was prevented by pharmacological seizure inhibition in Wag/Rij rats. Blocking activity-dependent myelination decreased seizure burden over time and reduced ictal synchrony as assessed by EEG coherence. These findings indicate that activity-dependent myelination driven by absence seizures contributes to epilepsy progression; maladaptive myelination may be pathogenic in some forms of epilepsy and other neurological diseases.
Collapse
Affiliation(s)
- Juliet K Knowles
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
| | - Haojun Xu
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.,Ph.D. Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan
| | - Caroline Soane
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Ankita Batra
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Tristan Saucedo
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Eleanor Frost
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Lydia T Tam
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Danielle Fraga
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Lijun Ni
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Katlin Villar
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Sydney Talmi
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
| | - Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA. .,Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
| |
Collapse
|
5
|
Bandopadhyay R, Singh T, Ghoneim MM, Alshehri S, Angelopoulou E, Paudel YN, Piperi C, Ahmad J, Alhakamy NA, Alfaleh MA, Mishra A. Recent Developments in Diagnosis of Epilepsy: Scope of MicroRNA and Technological Advancements. BIOLOGY 2021; 10:1097. [PMID: 34827090 PMCID: PMC8615191 DOI: 10.3390/biology10111097] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/21/2021] [Accepted: 10/21/2021] [Indexed: 12/18/2022]
Abstract
Epilepsy is one of the most common neurological disorders, characterized by recurrent seizures, resulting from abnormally synchronized episodic neuronal discharges. Around 70 million people worldwide are suffering from epilepsy. The available antiepileptic medications are capable of controlling seizures in around 60-70% of patients, while the rest remain refractory. Poor seizure control is often associated with neuro-psychiatric comorbidities, mainly including memory impairment, depression, psychosis, neurodegeneration, motor impairment, neuroendocrine dysfunction, etc., resulting in poor prognosis. Effective treatment relies on early and correct detection of epileptic foci. Although there are currently a few well-established diagnostic techniques for epilepsy, they lack accuracy and cannot be applied to patients who are unsupportive or harbor metallic implants. Since a single test result from one of these techniques does not provide complete information about the epileptic foci, it is necessary to develop novel diagnostic tools. Herein, we provide a comprehensive overview of the current diagnostic tools of epilepsy, including electroencephalography (EEG) as well as structural and functional neuroimaging. We further discuss recent trends and advances in the diagnosis of epilepsy that will enable more effective diagnosis and clinical management of patients.
Collapse
Affiliation(s)
- Ritam Bandopadhyay
- Department of Pharmacology, School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, Punjab, India;
| | - Tanveer Singh
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA;
| | - Mohammed M. Ghoneim
- Department of Pharmacy Practice, College of Pharmacy, AlMaarefa University, Ad Diriyah 13713, Saudi Arabia;
| | - Sultan Alshehri
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (E.A.); (C.P.)
| | - Yam Nath Paudel
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Subang Jaya 47500, Selangor, Malaysia;
| | - Christina Piperi
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (E.A.); (C.P.)
| | - Javed Ahmad
- Department of Pharmaceutics, College of Pharmacy, Najran University, Najran 11001, Saudi Arabia;
| | - Nabil A. Alhakamy
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (N.A.A.); (M.A.A.)
| | - Mohamed A. Alfaleh
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (N.A.A.); (M.A.A.)
- Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Awanish Mishra
- Department of Pharmacology, School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, Punjab, India;
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)—Guwahati, Changsari, Guwahati 781101, Assam, India
| |
Collapse
|
6
|
Rayatpour A, Farhangi S, Verdaguer E, Olloquequi J, Ureña J, Auladell C, Javan M. The Cross Talk between Underlying Mechanisms of Multiple Sclerosis and Epilepsy May Provide New Insights for More Efficient Therapies. Pharmaceuticals (Basel) 2021; 14:ph14101031. [PMID: 34681255 PMCID: PMC8541630 DOI: 10.3390/ph14101031] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/30/2021] [Accepted: 10/02/2021] [Indexed: 12/17/2022] Open
Abstract
Despite the significant differences in pathological background of neurodegenerative diseases, epileptic seizures are a comorbidity in many disorders such as Huntington disease (HD), Alzheimer's disease (AD), and multiple sclerosis (MS). Regarding the last one, specifically, it has been shown that the risk of developing epilepsy is three to six times higher in patients with MS compared to the general population. In this context, understanding the pathological processes underlying this connection will allow for the targeting of the common and shared pathological pathways involved in both conditions, which may provide a new avenue in the management of neurological disorders. This review provides an outlook of what is known so far about the bidirectional association between epilepsy and MS.
Collapse
Affiliation(s)
- Atefeh Rayatpour
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 14117-13116, Iran; (A.R.); (S.F.)
- Institute for Brain and Cognition, Tarbiat Modares University, Tehran 14117-13116, Iran
| | - Sahar Farhangi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 14117-13116, Iran; (A.R.); (S.F.)
- Institute for Brain and Cognition, Tarbiat Modares University, Tehran 14117-13116, Iran
| | - Ester Verdaguer
- Department of Cell Biology, Physiology and Immunology, Biology Faculty, Universitat de Barcelona, 08028 Barcelona, Spain; (E.V.); (J.U.)
- Centre for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Institute of Neuroscience, Universitat de Barcelona, 08035 Barcelona, Spain
| | - Jordi Olloquequi
- Laboratory of Cellular and Molecular Pathology, Biomedical Sciences Institute, Health Sciences Faculty, Universidad Autónoma de Chile, Talca 3460000, Chile;
| | - Jesus Ureña
- Department of Cell Biology, Physiology and Immunology, Biology Faculty, Universitat de Barcelona, 08028 Barcelona, Spain; (E.V.); (J.U.)
- Centre for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Institute of Neuroscience, Universitat de Barcelona, 08035 Barcelona, Spain
| | - Carme Auladell
- Department of Cell Biology, Physiology and Immunology, Biology Faculty, Universitat de Barcelona, 08028 Barcelona, Spain; (E.V.); (J.U.)
- Centre for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Institute of Neuroscience, Universitat de Barcelona, 08035 Barcelona, Spain
- Correspondence: (C.A.); (M.J.)
| | - Mohammad Javan
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 14117-13116, Iran; (A.R.); (S.F.)
- Institute for Brain and Cognition, Tarbiat Modares University, Tehran 14117-13116, Iran
- Cell Science Research Center, Department of Brain and Cognitive Sciences, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran 14117-13116, Iran
- Correspondence: (C.A.); (M.J.)
| |
Collapse
|
7
|
de Curtis M, Garbelli R, Uva L. A hypothesis for the role of axon demyelination in seizure generation. Epilepsia 2021; 62:583-595. [PMID: 33493363 DOI: 10.1111/epi.16824] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 01/06/2023]
Abstract
Loss of myelin and altered oligodendrocyte distribution in the cerebral cortex are commonly observed both in postsurgical tissue derived from different focal epilepsies (such as focal cortical dysplasias and tuberous sclerosis) and in animal models of focal epilepsy. Moreover, seizures are a frequent symptom in demyelinating diseases, such as multiple sclerosis, and in animal models of demyelination and oligodendrocyte dysfunction. Finally, the excessive activity reported in demyelinated axons may promote hyperexcitability. We hypothesize that the extracellular potassium rise generated during epileptiform activity may be amplified by the presence of axons without appropriate myelin coating and by alterations in oligodendrocyte function. This process could facilitate the triggering of recurrent spontaneous seizures in areas of altered myelination and could result in further demyelination, thus promoting epileptogenesis.
Collapse
Affiliation(s)
- Marco de Curtis
- Epilepsy Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Rita Garbelli
- Epilepsy Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Laura Uva
- Epilepsy Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy
| |
Collapse
|
8
|
Liu X, Bautista J, Liu E, Zikopoulos B. Imbalance of laminar-specific excitatory and inhibitory circuits of the orbitofrontal cortex in autism. Mol Autism 2020; 11:83. [PMID: 33081829 PMCID: PMC7574354 DOI: 10.1186/s13229-020-00390-x] [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: 05/19/2020] [Accepted: 10/06/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The human orbitofrontal cortex (OFC) is involved in assessing the emotional significance of events and stimuli, emotion-based learning, allocation of attentional resources, and social cognition. Little is known about the structure, connectivity and excitatory/inhibitory circuit interactions underlying these diverse functions in human OFC, as well as how the circuit is disrupted in individuals with autism spectrum disorder (ASD). METHODS We used post-mortem brain tissue from neurotypical adults and individuals with ASD. We examined the morphology and distribution of myelinated axons across cortical layers in OFC, at the single axon level, as a proxy of excitatory pathways. In the same regions, we also examined the laminar distribution of all neurons and neurochemically- and functionally-distinct inhibitory neurons that express the calcium-binding proteins parvalbumin (PV), calbindin (CB), and calretinin (CR). RESULTS We found that the density of myelinated axons increased consistently towards layer 6, while the average axon diameter did not change significantly across layers in both groups. However, both the density and diameter of myelinated axons were significantly lower in the ASD group compared with the Control group. The distribution pattern and density of the three major types of inhibitory neurons was comparable between groups, but there was a significant reduction in the density of excitatory neurons across OFC layers in ASD. LIMITATIONS This study is limited by the availability of human post-mortem tissue optimally processed for high-resolution microscopy and immunolabeling, especially from individuals with ASD. CONCLUSIONS The balance between excitation and inhibition in OFC is at the core of its function, assessing and integrating emotional and social cues with internal states and external inputs. Our preliminary results provide evidence for laminar-specific changes in the ratio of excitation/inhibition in OFC of adults with ASD, with an overall weakening and likely disorganization of excitatory signals and a relative strengthening of local inhibition. These changes likely underlie pathology of major OFC communications with limbic or other cortices and the amygdala in individuals with ASD, and may provide the anatomic basis for disrupted transmission of signals for social interactions and emotions in autism.
Collapse
Affiliation(s)
- Xuefeng Liu
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave., Room 401D, Boston, MA, 02215, USA
| | - Julied Bautista
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave., Room 401D, Boston, MA, 02215, USA
| | - Edward Liu
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave., Room 401D, Boston, MA, 02215, USA
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave., Room 401D, Boston, MA, 02215, USA. .,Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA. .,Graduate Program in Neuroscience, Boston University, Boston, MA, USA.
| |
Collapse
|
9
|
On the merits of non-invasive myelin imaging in epilepsy, a literature review. J Neurosci Methods 2020; 338:108687. [DOI: 10.1016/j.jneumeth.2020.108687] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/09/2020] [Accepted: 03/11/2020] [Indexed: 01/10/2023]
|
10
|
Therajaran P, Hamilton JA, O'Brien TJ, Jones NC, Ali I. Microglial polarization in posttraumatic epilepsy: Potential mechanism and treatment opportunity. Epilepsia 2020; 61:203-215. [PMID: 31943156 DOI: 10.1111/epi.16424] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/17/2022]
Abstract
Owing to the complexity of the pathophysiological mechanisms driving epileptogenesis following traumatic brain injury (TBI), effective preventive treatment approaches are not yet available for posttraumatic epilepsy (PTE). Neuroinflammation appears to play a critical role in the pathogenesis of the acquired epilepsies, including PTE, but despite a large preclinical literature demonstrating the ability of anti-inflammatory treatments to suppress epileptogenesis and chronic seizures, no anti-inflammatory treatment approaches have been clinically proven to date. TBI triggers robust inflammatory cascades, suggesting that they may be relevant for the pathogenesis of PTE. A major cell type involved in such cascades is the microglial cells-brain-resident immune cells that become activated after brain injury. When activated, these cells can oscillate between different phenotypes, and such polarization states are associated with the release of various pro- and anti-inflammatory mediators that may influence brain repair processes, and also differentially contribute to the development of PTE. As the molecular mechanisms and key signaling molecules associated with microglial polarization in brain are discovered, strategies are now emerging that can modulate this polarization, promoting this as a potential therapeutic strategy for PTE. In this review, we discuss the relevant literature regarding the polarization of brain-resident immune cells following TBI and attempt to put into perspective a role in epilepsy pathogenesis. Finally, we explore potential strategies that could polarize microglia/macrophages toward a neuroprotective phenotype to mitigate PTE development.
Collapse
Affiliation(s)
- Peravina Therajaran
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - John A Hamilton
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Terence J O'Brien
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia.,Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Nigel C Jones
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia.,Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Idrish Ali
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia.,Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| |
Collapse
|
11
|
Sun M, McDonald SJ, Brady RD, Collins-Praino L, Yamakawa GR, Monif M, O'Brien TJ, Cloud GC, Sobey CG, Mychasiuk R, Loane DJ, Shultz SR. The need to incorporate aged animals into the preclinical modeling of neurological conditions. Neurosci Biobehav Rev 2019; 109:114-128. [PMID: 31877345 DOI: 10.1016/j.neubiorev.2019.12.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/04/2019] [Accepted: 12/19/2019] [Indexed: 12/14/2022]
Abstract
Neurological conditions such as traumatic brain injury, stroke, Parkinson's disease, epilepsy, multiple sclerosis, and Alzheimer's disease are serious clinical problems that affect millions of people worldwide. The majority of clinical trials for these common conditions have failed, and there is a critical need to understand why treatments in preclinical animal models do not translate to patients. Many patients with these conditions are middle-aged or older, however, the majority of preclinical studies have used only young-adult animals. Considering that aging involves biological changes that are relevant to the pathobiology of neurological diseases, the lack of aged subjects in preclinical research could contribute to translational failures. This paper details how aging affects biological processes involved in neurological conditions, and reviews aging research in the context of traumatic brain injury, stroke, Parkinson's disease, epilepsy, multiple sclerosis, and Alzheimer's disease. We conclude that aging is an important, but often overlooked, factor that influences biology and outcomes in neurological conditions, and provide suggestions to improve our understanding and treatment of these diseases in aged patients.
Collapse
Affiliation(s)
- Mujun Sun
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia
| | - Stuart J McDonald
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia; Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC 3086, Australia
| | - Rhys D Brady
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, VIC 3052, Australia
| | - Lyndsey Collins-Praino
- Department of Medical Sciences, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Glenn R Yamakawa
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia
| | - Mastura Monif
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, VIC 3052, Australia; Department of Neurology, Alfred Health, Melbourne, VIC 3004, Australia
| | - Geoffrey C Cloud
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia; Department of Stroke Services, Alfred Hospital, Melbourne, VIC 3004, Australia
| | - Christopher G Sobey
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC 3086, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia
| | - David J Loane
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College, Dublin 2, Ireland
| | - Sandy R Shultz
- Department of Neuroscience, Monash University, Melbourne, VIC 3004, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, VIC 3052, Australia; Department of Neurology, Alfred Health, Melbourne, VIC 3004, Australia.
| |
Collapse
|
12
|
Leung WL, Casillas-Espinosa P, Sharma P, Perucca P, Powell K, O'Brien TJ, Semple BD. An animal model of genetic predisposition to develop acquired epileptogenesis: The FAST and SLOW rats. Epilepsia 2019; 60:2023-2036. [PMID: 31468516 DOI: 10.1111/epi.16329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 08/06/2019] [Accepted: 08/06/2019] [Indexed: 12/12/2022]
Abstract
Epidemiological data and gene association studies suggest a genetic predisposition to developing epilepsy after an acquired brain insult, such as traumatic brain injury. An improved understanding of genetic determinants of vulnerability is imperative for early disease diagnosis and prognosis prediction, with flow-on benefits for the development of targeted antiepileptogenic treatments as well as optimal clinical trial design. In the laboratory, one approach to investigate why some individuals are more vulnerable to acquired epilepsy than others is to examine unique rodent models exhibiting either vulnerability or resistance to epileptogenesis. This review focuses on the most well-characterized of these models, the FAST (seizure-prone) and SLOW (seizure-resistant) rat strains, which were derived by selective breeding for differential amygdala electrical kindling rates. We describe how these strains differ in their seizure profiles, neuroanatomy, and neurobehavioral phenotypes, both at baseline and after a brain insult, with this knowledge proving fruitful to identify common pathological abnormalities associated with seizure susceptibility and psychiatric comorbidities. It is important to note that accruing data on strain differences in multiple biological processes provides insight into why some individuals may be more vulnerable to epileptogenesis, although future studies are evidently needed to identify the precise molecular and genetic risk factors. Together, the FAST and SLOW rat strains, and other similar experimental models, are invaluable neurobiological tools to investigate the effect of genetic background on acquired epilepsy risk, as well as the poorly understood relationship between epilepsy development and associated comorbidities.
Collapse
Affiliation(s)
- Wai Lam Leung
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia
| | - Pablo Casillas-Espinosa
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia
| | - Pragati Sharma
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia.,Department of Neurology, Alfred Health, Melbourne, Vic., Australia
| | - Piero Perucca
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia.,Department of Neurology, Alfred Health, Melbourne, Vic., Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - Kim Powell
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia
| | - Terence J O'Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia.,Department of Neurology, Alfred Health, Melbourne, Vic., Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - Bridgette D Semple
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia
| |
Collapse
|
13
|
Neuroimaging Biomarkers of Experimental Epileptogenesis and Refractory Epilepsy. Int J Mol Sci 2019; 20:ijms20010220. [PMID: 30626103 PMCID: PMC6337422 DOI: 10.3390/ijms20010220] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 12/31/2018] [Accepted: 01/03/2019] [Indexed: 11/17/2022] Open
Abstract
This article provides an overview of neuroimaging biomarkers in experimental epileptogenesis and refractory epilepsy. Neuroimaging represents a gold standard and clinically translatable technique to identify neuropathological changes in epileptogenesis and longitudinally monitor its progression after a precipitating injury. Neuroimaging studies, along with molecular studies from animal models, have greatly improved our understanding of the neuropathology of epilepsy, such as the hallmark hippocampus sclerosis. Animal models are effective for differentiating the different stages of epileptogenesis. Neuroimaging in experimental epilepsy provides unique information about anatomic, functional, and metabolic alterations linked to epileptogenesis. Recently, several in vivo biomarkers for epileptogenesis have been investigated for characterizing neuronal loss, inflammation, blood-brain barrier alterations, changes in neurotransmitter density, neurovascular coupling, cerebral blood flow and volume, network connectivity, and metabolic activity in the brain. Magnetic resonance imaging (MRI) is a sensitive method for detecting structural and functional changes in the brain, especially to identify region-specific neuronal damage patterns in epilepsy. Positron emission tomography (PET) and single-photon emission computerized tomography are helpful to elucidate key functional alterations, especially in areas of brain metabolism and molecular patterns, and can help monitor pathology of epileptic disorders. Multimodal procedures such as PET-MRI integrated systems are desired for refractory epilepsy. Validated biomarkers are warranted for early identification of people at risk for epilepsy and monitoring of the progression of medical interventions.
Collapse
|
14
|
Sharma P, Powell KL, Wlodek ME, O'Brien TJ, Gilby KL. Delayed myelination and neurodevelopment in male seizure-prone versus seizure-resistant rats. Epilepsia 2018; 59:753-764. [PMID: 29377096 DOI: 10.1111/epi.14013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2018] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Aberrant myelination and developmental delay have been reported in epilepsy. However, it is unclear whether these are linked to intrinsic mechanisms that support a predisposition toward seizures and the development of epilepsy. Thus, we compared rates of myelination and neurodevelopment in male rats selectively bred for enhanced susceptibility to kindling epileptogenesis (FAST) with male rats bred for resistance (SLOW). METHODS Myelin-specific gene expression was compared in the brainstem, cerebellum, and cerebral hemisphere of FAST and SLOW rats on postnatal days (PNDs) 5, 11, 17, 23, and 90 to determine strain-specific myelination rates. Myelin protein levels were also compared at PNDs 5 and 23 in the brainstem. Relative rates of neurodevelopment were evaluated between PNDs 5 and 21 using physical growth landmarks and neuromotor tests including righting reflex, cliff avoidance, negative geotaxis, and locomotor activity. RESULTS Myelin-specific mRNA expression was significantly down-regulated in FAST rats on PNDs 5 and 11 in all 3 brain structures, indicating relatively delayed myelination. Likewise, corresponding protein levels were significantly lower in FAST brainstem on PND 5. Developmental delay was evident in the FAST strain such that only 9% of FAST pups, compared to 81% of SLOW, had open eyes by PND 13, locomotor activity was significantly reduced between PNDs 12 and 16, and neuromotor task acquisition was delayed between PNDs 5 and 10. SIGNIFICANCE Relative delays in myelination and neurodevelopment co-occurred in the seizure-prone FAST strain in the absence of seizures. These findings suggest these symptoms are not seizure-induced and may be mechanistically linked to an underlying pathophysiology supporting a predisposition toward developing epilepsy.
Collapse
Affiliation(s)
- Pragati Sharma
- Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - Kim L Powell
- Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - Mary E Wlodek
- Department of Physiology, University of Melbourne, Parkville, Vic., Australia
| | - Terence J O'Brien
- Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - Krista L Gilby
- Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, Vic., Australia
| |
Collapse
|
15
|
Neuroimaging in animal models of epilepsy. Neuroscience 2017; 358:277-299. [DOI: 10.1016/j.neuroscience.2017.06.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 02/06/2023]
|
16
|
Wright DK, O'Brien TJ, Shultz SR, Mychasiuk R. Sex matters: repetitive mild traumatic brain injury in adolescent rats. Ann Clin Transl Neurol 2017; 4:640-654. [PMID: 28904986 PMCID: PMC5590540 DOI: 10.1002/acn3.441] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 12/20/2022] Open
Abstract
Objective Whether sex differences contribute to the heterogeneity of mild traumatic brain injury (mTBI) and repeated mTBI (RmTBI) outcomes in adolescents is unknown. Therefore, this study examined changes in, and differences between, male and female rats following single mTBI and RmTBI. Methods Rats were given a single mTBI, RmTBI (i.e., 3x), or sham injuries. Injuries were administered using a lateral impact model that mimics forces common in human mTBI. After the final injury, rats underwent extensive behavioral testing to examine cognition, motor function, and anxiety‐ and depressive‐like behavior. Postmortem analyses investigated gene expression and structural changes in the brain. Results Many of the outcomes exhibited a sex‐dependent response to RmTBI. While all rats given RmTBI had deficits in balance, motor coordination, locomotion, and anxiety‐like behavior, only male rats given RmTBI had short‐term working memory deficits, whereas only females given RmTBI had increased depressive‐like behavior. Volumetric and diffusion weighted MRI analyses found that while RmTBI‐induced atrophy of the prefrontal cortex was greater in female rats, only the male rats exhibited worse white matter integrity in the corpus callosum following RmTBI. Sex‐dependent changes in brain expression of mRNA for glial fibrillary acidic protein, myelin basic protein, and tau protein were also observed following injury. Interpretation These findings suggest that in adolescent mTBI, sex matters; and future studies incorporating both male and females are warranted to provide a greater understanding of injury prognosis and better inform clinical practice.
Collapse
Affiliation(s)
- David K Wright
- Anatomy and Neuroscience The University of Melbourne Parkville Victoria 3010 Australia.,The Florey Institute of Neuroscience and Mental Health Parkville Victoria 3052 Australia
| | - Terence J O'Brien
- Department of Medicine The Royal Melbourne Hospital The University of Melbourne Parkville Victoria 3050 Australia
| | - Sandy R Shultz
- Department of Medicine The Royal Melbourne Hospital The University of Melbourne Parkville Victoria 3050 Australia
| | - Richelle Mychasiuk
- Department of Psychology Alberta Children's Hospital Research Institute University of Calgary Calgary Alberta Canada
| |
Collapse
|