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Villa BR, George AG, Shutt TE, Sullivan PG, Rho JM, Teskey GC. Postictal hypoxia involves reactive oxygen species and is ameliorated by chronic mitochondrial uncoupling. Neuropharmacology 2023; 238:109653. [PMID: 37422182 DOI: 10.1016/j.neuropharm.2023.109653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/10/2023]
Abstract
Prolonged severe hypoxia follows brief seizures and represents a mechanism underlying several negative postictal manifestations without interventions. Approximately 50% of the postictal hypoxia phenomenon can be accounted for by arteriole vasoconstriction. What accounts for the rest of the drop in unbound oxygen is unclear. Here, we determined the effect of pharmacological modulation of mitochondrial function on tissue oxygenation in the hippocampus of rats after repeatedly evoked seizures. Rats were treated with mitochondrial uncoupler 2,4 dinitrophenol (DNP) or antioxidants. Oxygen profiles were recorded using a chronically implanted oxygen-sensing probe, before, during, and after seizure induction. Mitochondrial function and redox tone were measured using in vitro mitochondrial assays and immunohistochemistry. Postictal cognitive impairment was assessed using the novel object recognition task. Mild mitochondrial uncoupling by DNP raised hippocampal oxygen tension and ameliorated postictal hypoxia. Chronic DNP also lowered mitochondrial oxygen-derived reactive species and oxidative stress in the hippocampus during postictal hypoxia. Uncoupling the mitochondria exerts therapeutic benefits on postictal cognitive dysfunction. Finally, antioxidants do not affect postictal hypoxia, but protect the brain from associated cognitive deficits. We provided evidence for a metabolic component of the prolonged oxygen deprivation that follow seizures and its pathological sequelae. Furthermore, we identified a molecular underpinning of this metabolic component, which involves excessive oxygen conversion into reactive species. Mild mitochondrial uncoupling may be a potential therapeutic strategy to treat the postictal state where seizure control is absent or poor.
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Affiliation(s)
- Bianca R Villa
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada.
| | - Antis G George
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada.
| | - Timothy E Shutt
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada; Departments of Medical Genetics and Biochemistry & Molecular Biology, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada; Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
| | - Patrick G Sullivan
- Department of Anatomy and Neurobiology, and Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, 40536, USA.
| | - Jong M Rho
- Department of Neurosciences, Pediatrics and Pharmacology, University of California San Diego, Rady Children's Hospital, San Diego, CA, 92037, USA.
| | - G Campbell Teskey
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada; Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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2
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Villa BR, Bhatt D, Wolff MD, Addo-Osafo K, Epp JR, Teskey GC. Repeated episodes of postictal hypoxia are a mechanism for interictal cognitive impairments. Sci Rep 2023; 13:15474. [PMID: 37726428 PMCID: PMC10509159 DOI: 10.1038/s41598-023-42741-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 09/14/2023] [Indexed: 09/21/2023] Open
Abstract
Comorbidities during the period between seizures present a significant challenge for individuals with epilepsy. Despite their clinical relevance, the pathophysiology of the interictal symptomatology is largely unknown. Postictal severe hypoxia (PIH) in those brain regions participating in the seizure has been indicated as a mechanism underlying several negative postictal manifestations. It is unknown how repeated episodes of PIH affect interictal symptoms in epilepsy. Using a rat model, we observed that repeated seizures consistently induced episodes of PIH that become increasingly severe with each seizure occurrence. Additionally, recurrent seizure activity led to decreased levels of oxygen in the hippocampus during the interictal period. However, these reductions were prevented when we repeatedly blocked PIH using either the COX-inhibitor acetaminophen or the L-type calcium channel antagonist nifedipine. Moreover, we found that interictal cognitive deficits caused by seizures were completely alleviated by repeated attenuation of PIH events. Lastly, mitochondrial dysfunction may contribute to the observed pathological outcomes during the interictal period. These findings provide evidence that seizure-induced hypoxia may play a crucial role in several aspects of epilepsy. Consequently, developing and implementing treatments that specifically target and prevent PIH could potentially offer significant benefits for individuals with refractory epilepsy.
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Affiliation(s)
- Bianca R Villa
- Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada.
- Department of Cell Biology and Anatomy, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
| | - Dhyey Bhatt
- Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Cell Biology and Anatomy, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Marshal D Wolff
- Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Cell Biology and Anatomy, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Kwaku Addo-Osafo
- Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Cell Biology and Anatomy, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Jonathan R Epp
- Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Cell Biology and Anatomy, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - G Campbell Teskey
- Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Cell Biology and Anatomy, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
- Cumming School of Medicine, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
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George AG, Farrell JS, Colangeli R, Wall AK, Gom RC, Kesler MT, Rodriguez de la Hoz C, Villa BR, Perera T, Rho JM, Kurrasch D, Teskey GC. Sudden unexpected death in epilepsy is prevented by blocking postictal hypoxia. Neuropharmacology 2023; 231:109513. [PMID: 36948357 DOI: 10.1016/j.neuropharm.2023.109513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/21/2023] [Accepted: 03/18/2023] [Indexed: 03/24/2023]
Abstract
Epilepsy is at times a fatal disease. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality in people with intractable epilepsy and is defined by exclusion; non-accidental, non-toxicologic, and non-anatomic causes of death. While SUDEP often follows a bilateral tonic-clonic seizure, the mechanisms that ultimately lead to terminal apnea and then asystole remain elusive and there is a lack of preventative treatments. Based on the observation that discrete seizures lead to local and postictal vasoconstriction, resulting in hypoperfusion, hypoxia and behavioural disturbances in the forebrain we reasoned those similar mechanisms may play a role in SUDEP when seizures invade the brainstem. Here we tested this neurovascular-based hypothesis of SUDEP in awake non-anesthetized mice by pharmacologically preventing seizure-induced vasoconstriction, with cyclooxygenase-2 or L-type calcium channel antagonists. In both acute and chronic mouse models of seizure-induced premature mortality, ibuprofen and nicardipine extended life while systemic drug levels remained high enough to be effective. We also examined the potential role of spreading depolarization in the acute model of seizure-induced premature mortality. These data provide a proof-of-principle for the neurovascular hypothesis of SUDEP rather than spreading depolarization and the use of currently available drugs to prevent it.
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Affiliation(s)
- Antis G George
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Jordan S Farrell
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Neurosurgery, Stanford University, Palo Alto, CA, 94305, USA
| | - Roberto Colangeli
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Marche Polytechnic University, Ancona, Italy
| | - Alexandra K Wall
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Renaud C Gom
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Mitchell T Kesler
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | | | - Bianca R Villa
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Tefani Perera
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Jong M Rho
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Neurosciences, Pediatrics and Pharmacology, University of California, San Diego and Rady Children's Hospital, San Diego, CA, USA
| | - Deborah Kurrasch
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Medical Genetics, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - G Campbell Teskey
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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4
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Gom RC, Bhatt D, Villa BR, George AG, Lohman AW, Mychasiuk R, Rho JM, Teskey GC. The ketogenic diet raises brain oxygen levels, attenuates postictal hypoxia, and protects against learning impairments. Neurobiol Dis 2021; 154:105335. [PMID: 33741453 DOI: 10.1016/j.nbd.2021.105335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/26/2021] [Accepted: 03/14/2021] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVES A prolonged vasoconstriction/hypoperfusion/hypoxic event follows self-terminating focal seizures. The ketogenic diet (KD) has demonstrated efficacy as a metabolic treatment for intractable epilepsy and other disorders but its effect on local brain oxygen levels is completely unknown. This study investigated the effects of the KD on tissue oxygenation in the hippocampus before and after electrically elicited (kindled) seizures and whether it could protect against a seizure-induced learning impairment. We also examined the effects of the ketone β-hydroxybutyrate (BHB) as a potential underlying mechanism. METHODS Male and female rats were given access to one of three diet protocols 2 weeks prior to the initiation of seizures: KD, caloric restricted standard chow, and ad libitum standard chow. Dorsal hippocampal oxygen levels were measured prior to initiation of diets as well as before and after a 10-day kindling paradigm. Male rats were then tested on a novel object recognition task to assess postictal learning impairments. In a separate cohort, BHB was administered 30 min prior to seizure elicitation to determine whether it influenced oxygen dynamics. RESULTS The KD increased dorsal hippocampal oxygen levels, ameliorated postictal hypoxia, and prevented postictal learning impairments. Acute BHB administration did not alter oxygen levels before or after seizures. INTERPRETATION The ketogenic diet raised brain oxygen levels and attenuated severe postictal hypoxia likely through a mechanism independent of ketosis and shows promise as a non-pharmacological treatment to prevent the postictal state.
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Affiliation(s)
- Renaud C Gom
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada.
| | - Dhyey Bhatt
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
| | - Bianca R Villa
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
| | - Antis G George
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
| | - Alexander W Lohman
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - Jong M Rho
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Cumming School of Medicine University of Calgary, Calgary, CA, Canada; Departments of Neurosciences and Pediatrics, University of California San Diego, Rady Children's Hospital San Diego, California, USA
| | - G Campbell Teskey
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, CA, Canada
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5
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Pauletti A, Terrone G, Shekh-Ahmad T, Salamone A, Ravizza T, Rizzi M, Pastore A, Pascente R, Liang LP, Villa BR, Balosso S, Abramov AY, van Vliet EA, Del Giudice E, Aronica E, Patel M, Walker MC, Vezzani A. Targeting oxidative stress improves disease outcomes in a rat model of acquired epilepsy. Brain 2019; 142:e39. [PMID: 31145451 PMCID: PMC6598637 DOI: 10.1093/brain/awz130] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/17/2017] [Accepted: 03/26/2017] [Indexed: 01/07/2023] Open
Abstract
Epilepsy therapy is based on antiseizure drugs that treat the symptom, seizures, rather than the disease and are ineffective in up to 30% of patients. There are no treatments for modifying the disease-preventing seizure onset, reducing severity or improving prognosis. Among the potential molecular targets for attaining these unmet therapeutic needs, we focused on oxidative stress since it is a pathophysiological process commonly occurring in experimental epileptogenesis and observed in human epilepsy. Using a rat model of acquired epilepsy induced by electrical status epilepticus, we show that oxidative stress occurs in both neurons and astrocytes during epileptogenesis, as assessed by measuring biochemical and histological markers. This evidence was validated in the hippocampus of humans who died following status epilepticus. Oxidative stress was reduced in animals undergoing epileptogenesis by a transient treatment with N-acetylcysteine and sulforaphane, which act to increase glutathione levels through complementary mechanisms. These antioxidant drugs are already used in humans for other therapeutic indications. This drug combination transiently administered for 2 weeks during epileptogenesis inhibited oxidative stress more efficiently than either drug alone. The drug combination significantly delayed the onset of epilepsy, blocked disease progression between 2 and 5 months post-status epilepticus and drastically reduced the frequency of spontaneous seizures measured at 5 months without modifying the average seizure duration or the incidence of epilepsy in animals. Treatment also decreased hippocampal neuron loss and rescued cognitive deficits. Oxidative stress during epileptogenesis was associated with de novo brain and blood generation of high mobility group box 1 (HMGB1), a neuroinflammatory molecule implicated in seizure mechanisms. Drug-induced reduction of oxidative stress prevented HMGB1 generation, thus highlighting a potential novel mechanism contributing to therapeutic effects. Our data show that targeting oxidative stress with clinically used drugs for a limited time window starting early after injury significantly improves long-term disease outcomes. This intervention may be considered for patients exposed to potential epileptogenic insults.
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Affiliation(s)
- Alberto Pauletti
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Gaetano Terrone
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Tawfeeq Shekh-Ahmad
- 2 Department of Clinical and Experimental Epilepsy, University College
London, UK
| | - Alessia Salamone
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Teresa Ravizza
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Massimo Rizzi
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Anna Pastore
- 3 Metabolomics and Proteomics Unit, ‘Bambino Gesù’ Children’s Hospital,
IRCCS, Rome, Italy
| | - Rosaria Pascente
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Li-Ping Liang
- 4 Department of Pharmaceutical Sciences, University of Colorado Denver,
Aurora, Colorado, USA
| | - Bianca R Villa
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Silvia Balosso
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Andrey Y Abramov
- 2 Department of Clinical and Experimental Epilepsy, University College
London, UK
| | - Erwin A van Vliet
- 5 Department of (Neuro)Pathology, Academic Medical Center, University of
Amsterdam, The Netherlands
| | - Ennio Del Giudice
- 6 Department of Translational Medical Sciences, Section of Pediatrics,
Federico II University, Naples, Italy
| | - Eleonora Aronica
- 5 Department of (Neuro)Pathology, Academic Medical Center, University of
Amsterdam, The Netherlands
- 7 Stichting Epilepsie Instellingen Nederland, Amsterdam, The
Netherlands
| | - Manisha Patel
- 4 Department of Pharmaceutical Sciences, University of Colorado Denver,
Aurora, Colorado, USA
| | - Matthew C Walker
- 2 Department of Clinical and Experimental Epilepsy, University College
London, UK
| | - Annamaria Vezzani
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
- Correpondence to: Annamaria Vezzani, PhD Department of Neuroscience
IRCCS-Istituto di Ricerche Farmacologiche Mario Negri Via G. La Masa 19, 20156 Milano,
Italy E-mail:
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6
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Terrone G, Pauletti A, Salamone A, Rizzi M, Villa BR, Porcu L, Sheehan MJ, Guilmette E, Butler CR, Piro JR, Samad TA, Vezzani A. Inhibition of monoacylglycerol lipase terminates diazepam-resistant status epilepticus in mice and its effects are potentiated by a ketogenic diet. Epilepsia 2017; 59:79-91. [DOI: 10.1111/epi.13950] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Gaetano Terrone
- Department of Neuroscience; IRCCS-Mario Negri Institute for Pharmacological Research; Milano Italy
| | - Alberto Pauletti
- Department of Neuroscience; IRCCS-Mario Negri Institute for Pharmacological Research; Milano Italy
| | - Alessia Salamone
- Department of Neuroscience; IRCCS-Mario Negri Institute for Pharmacological Research; Milano Italy
| | - Massimo Rizzi
- Department of Neuroscience; IRCCS-Mario Negri Institute for Pharmacological Research; Milano Italy
| | - Bianca R. Villa
- Department of Neuroscience; IRCCS-Mario Negri Institute for Pharmacological Research; Milano Italy
| | - Luca Porcu
- Department of Oncology; IRCCS-Mario Negri Institute for Pharmacological Research; Milano Italy
| | - Mark J. Sheehan
- Internal Medicine Research Unit; Pfizer Worldwide Research and Development; Cambridge MA USA
| | - Edward Guilmette
- Internal Medicine Research Unit; Pfizer Worldwide Research and Development; Cambridge MA USA
| | | | - Justin R. Piro
- Internal Medicine Research Unit; Pfizer Worldwide Research and Development; Cambridge MA USA
| | - Tarek A. Samad
- Internal Medicine Research Unit; Pfizer Worldwide Research and Development; Cambridge MA USA
| | - Annamaria Vezzani
- Department of Neuroscience; IRCCS-Mario Negri Institute for Pharmacological Research; Milano Italy
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7
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Pauletti A, Terrone G, Shekh-Ahmad T, Salamone A, Ravizza T, Rizzi M, Pastore A, Pascente R, Liang LP, Villa BR, Balosso S, Abramov AY, van Vliet EA, Del Giudice E, Aronica E, Antoine DJ, Patel M, Walker MC, Vezzani A. Targeting oxidative stress improves disease outcomes in a rat model of acquired epilepsy. Brain 2017; 140:1885-1899. [PMID: 28575153 DOI: 10.1093/brain/awx117] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/26/2017] [Indexed: 12/31/2022] Open
Abstract
Epilepsy therapy is based on antiseizure drugs that treat the symptom, seizures, rather than the disease and are ineffective in up to 30% of patients. There are no treatments for modifying the disease-preventing seizure onset, reducing severity or improving prognosis. Among the potential molecular targets for attaining these unmet therapeutic needs, we focused on oxidative stress since it is a pathophysiological process commonly occurring in experimental epileptogenesis and observed in human epilepsy. Using a rat model of acquired epilepsy induced by electrical status epilepticus, we show that oxidative stress occurs in both neurons and astrocytes during epileptogenesis, as assessed by measuring biochemical and histological markers. This evidence was validated in the hippocampus of humans who died following status epilepticus. Oxidative stress was reduced in animals undergoing epileptogenesis by a transient treatment with N-acetylcysteine and sulforaphane, which act to increase glutathione levels through complementary mechanisms. These antioxidant drugs are already used in humans for other therapeutic indications. This drug combination transiently administered for 2 weeks during epileptogenesis inhibited oxidative stress more efficiently than either drug alone. The drug combination significantly delayed the onset of epilepsy, blocked disease progression between 2 and 5 months post-status epilepticus and drastically reduced the frequency of spontaneous seizures measured at 5 months without modifying the average seizure duration or the incidence of epilepsy in animals. Treatment also decreased hippocampal neuron loss and rescued cognitive deficits. Oxidative stress during epileptogenesis was associated with de novo brain and blood generation of disulfide high mobility group box 1 (HMGB1), a neuroinflammatory molecule implicated in seizure mechanisms. Drug-induced reduction of oxidative stress prevented disulfide HMGB1 generation, thus highlighting a potential novel mechanism contributing to therapeutic effects. Our data show that targeting oxidative stress with clinically used drugs for a limited time window starting early after injury significantly improves long-term disease outcomes. This intervention may be considered for patients exposed to potential epileptogenic insults.
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Affiliation(s)
- Alberto Pauletti
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Gaetano Terrone
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Tawfeeq Shekh-Ahmad
- Department of Clinical and Experimental Epilepsy, University College London, UK
| | - Alessia Salamone
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Teresa Ravizza
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Massimo Rizzi
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Anna Pastore
- Metabolomics and Proteomics Unit, 'Bambino Gesù' Children's Hospital, IRCCS, Rome, Italy
| | - Rosaria Pascente
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Li-Ping Liang
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, USA
| | - Bianca R Villa
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Silvia Balosso
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Andrey Y Abramov
- Department of Clinical and Experimental Epilepsy, University College London, UK
| | - Erwin A van Vliet
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Ennio Del Giudice
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University, Naples, Italy
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland, Amsterdam, The Netherlands
| | - Daniel J Antoine
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, USA
| | - Matthew C Walker
- Department of Clinical and Experimental Epilepsy, University College London, UK
| | - Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
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8
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Abstract
To investigate the role of actin in vertebrate nerve terminals, nerve-muscle preparations from garter snake (Thamnophis sirtalis) were treated with the actin-depolymerizing agent latrunculin A. Immunostaining revealed that actin filaments within presynaptic motor terminal boutons were disrupted by the drug. In preparations loaded with the optical probe FM1-43, destaining was reduced by latrunculin treatment, suggesting that transmitter release was partially blocked. Latrunculin treatment did not influence the amplitude or time course of spontaneous miniature endplate potentials (MEPPs). Similarly, endplate potentials (EPPs) evoked at low frequency were comparable in control and latrunculin-treated curarized preparations. Brief tetanic stimulation of the muscle nerve (25 Hz, 90 s) depressed EPP amplitudes in both control and latrunculin-treated preparations. After tetanus, EPPs elicited at 0. 2 Hz in control preparations recovered rapidly (0-5 min) and completely (usually potentiating to above pre-tetanus levels; 130 +/- 11 %, mean +/- s.e.m.). In contrast, EPPs evoked in latrunculin-treated preparations recovered slowly (8-10 min) and incompletely (84 +/- 8 %). The influence of latrunculin on post-tetanic EPPs depended on its concentration in the bath (KD = 3. 1 microM) and on time of incubation. These observations argue that actin filaments facilitate transmitter release rather than impede it. Specifically, actin may facilitate mobilization of vesicles towards the releasable pools.
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Affiliation(s)
- J C Cole
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO, USA
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