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Fakhfouri G, Mijailović NR, Rahimian R. Psychiatric Comorbidities of Inflammatory Bowel Disease: It Is a Matter of Microglia's Gut Feeling. Cells 2024; 13:177. [PMID: 38247868 PMCID: PMC10814793 DOI: 10.3390/cells13020177] [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: 12/07/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/23/2024] Open
Abstract
Inflammatory bowel disease (IBD), a common term for Crohn's disease and ulcerative colitis, is a chronic, relapse-remitting condition of the gastrointestinal tract that is increasing worldwide. Psychiatric comorbidities, including depression and anxiety, are more prevalent in IBD patients than in healthy individuals. Evidence suggests that varying levels of neuroinflammation might underlie these states in IBD patients. Within this context, microglia are the crucial non-neural cells in the brain responsible for innate immune responses following inflammatory insults. Alterations in microglia's functions, such as secretory profile, phagocytic activity, and synaptic pruning, might play significant roles in mediating psychiatric manifestations of IBD. In this review, we discuss the role played by microglia in IBD-associated comorbidities.
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Affiliation(s)
- Gohar Fakhfouri
- Department of Psychiatry, Douglas Hospital, McGill University, Montreal, QC H4H 1R3, Canada;
| | - Nataša R. Mijailović
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia;
| | - Reza Rahimian
- McGill Group for Suicide Studies, Douglas Mental Health Institute, McGill University, 6875 Boulevard LaSalle, Montreal, QC H4H 1R3, Canada
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Riva A, Pozzati E, Grasso M, De Caro C, Russo E, Verrotti A, Striano P. Targeting the MGBA with -biotics in epilepsy: New insights from preclinical and clinical studies. Neurobiol Dis 2022; 170:105758. [PMID: 35588991 DOI: 10.1016/j.nbd.2022.105758] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 05/09/2022] [Accepted: 05/11/2022] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Data accumulation reveals that the bidirectional communication between the gut microbiota and the brain, called the microbiota-gut-brain axis (MGBA), can be modulated by different compounds including prebiotics, probiotics, symbiotic (a fair combination of both), and diet, thus exerting a beneficial impact on brain activity and behaviors. This review aims to give an overview of the possible beneficial effects of the supplementation of -biotics in epilepsy treatment. METHODS A search on PubMed and ClinicalTrials.gov databases using the terms "probiotics", OR "prebiotics", AND "gut microbiota", AND "epilepsy" was performed. The search covered the period of the last eleven years (2010-2021). CONCLUSIONS Nowadays, studies analyzing the clinical impact of gut microbiota-modulating intervention strategies on epilepsy are limited and heterogenous due either to the different experimental populations studied (i.e., genetic vs lesional mouse models) or the various primary outcomes measure evaluated. However, positive effects have invariably been noticed; particularly, there have been improvements in behavioral comorbidities and associated gastrointestinal (GI) symptoms. More studies will be needed in the next few years to strictly evaluate the feasibility to introduce these new therapeutic strategies in the clinical treatment of highly refractory epilepsies.
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Affiliation(s)
- Antonella Riva
- Paediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, Università degli Studi di Genova, Genova, Italy
| | - Elisa Pozzati
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, Università degli Studi di Genova, Genova, Italy
| | - Mattia Grasso
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, Università degli Studi di Genova, Genova, Italy
| | - Carmen De Caro
- Science of Health Department, School of Medicine, University of Catanzaro, Catanzaro, Italy
| | - Emilio Russo
- Science of Health Department, School of Medicine, University of Catanzaro, Catanzaro, Italy
| | - Alberto Verrotti
- Department of Paediatrics, University of Perugia, Perugia, Italy
| | - Pasquale Striano
- Paediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, Università degli Studi di Genova, Genova, Italy.
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Barnes SE, Zera KA, Ivison GT, Buckwalter MS, Engleman EG. Brain profiling in murine colitis and human epilepsy reveals neutrophils and TNFα as mediators of neuronal hyperexcitability. J Neuroinflammation 2021; 18:199. [PMID: 34511110 PMCID: PMC8436533 DOI: 10.1186/s12974-021-02262-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 08/30/2021] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Patients with chronic inflammatory disorders such as inflammatory bowel disease frequently experience neurological complications including epilepsy, depression, attention deficit disorders, migraines, and dementia. However, the mechanistic basis for these associations is unknown. Given that many patients are unresponsive to existing medications or experience debilitating side effects, novel therapeutics that target the underlying pathophysiology of these conditions are urgently needed. METHODS Because intestinal disorders such as inflammatory bowel disease are robustly associated with neurological symptoms, we used three different mouse models of colitis to investigate the impact of peripheral inflammatory disease on the brain. We assessed neuronal hyperexcitability, which is associated with many neurological symptoms, by measuring seizure threshold in healthy and colitic mice. We profiled the neuroinflammatory phenotype of colitic mice and used depletion and neutralization assays to identify the specific mediators responsible for colitis-induced neuronal hyperexcitability. To determine whether our findings in murine models overlapped with a human phenotype, we performed gene expression profiling, pathway analysis, and deconvolution on microarray data from hyperexcitable human brain tissue from patients with epilepsy. RESULTS We observed that murine colitis induces neuroinflammation characterized by increased pro-inflammatory cytokine production, decreased tight junction protein expression, and infiltration of monocytes and neutrophils into the brain. We also observed sustained neuronal hyperexcitability in colitic mice. Colitis-induced neuronal hyperexcitability was ameliorated by neutrophil depletion or TNFα blockade. Gene expression profiling of hyperexcitable brain tissue resected from patients with epilepsy also revealed a remarkably similar pathology to that seen in the brains of colitic mice, including neutrophil infiltration and high TNFα expression. CONCLUSIONS Our results reveal neutrophils and TNFα as central regulators of neuronal hyperexcitability of diverse etiology. Thus, there is a strong rationale for evaluating anti-inflammatory agents, including clinically approved TNFα inhibitors, for the treatment of neurological and psychiatric symptoms present in, and potentially independent of, a diagnosed inflammatory disorder.
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Affiliation(s)
- Sarah E Barnes
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Kristy A Zera
- Department of Neurology, Stanford University, Stanford, CA, USA
| | - Geoffrey T Ivison
- Department of Pathology, Stanford University, Stanford, CA, USA
- Department of Infectious Diseases, Stanford University, Stanford, CA, USA
| | | | - Edgar G Engleman
- Department of Pathology, Stanford University, Stanford, CA, USA.
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De Caro C, Iannone LF, Citraro R, Striano P, De Sarro G, Constanti A, Cryan JF, Russo E. Can we 'seize' the gut microbiota to treat epilepsy? Neurosci Biobehav Rev 2019; 107:750-764. [PMID: 31626816 DOI: 10.1016/j.neubiorev.2019.10.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 02/08/2023]
Abstract
The gut-microbiota, the complex intestinal microbial ecosystem essential to health, is an emerging concept in medicine. Several studies demonstrate a microbiota-gut-brain bidirectional connection via neural, endocrine, metabolic and immune pathways. Accordingly, the gut microbiota has a crucial role in modulating intestinal permeability, to alter local/peripheral immune responses and in production of essential metabolites and neurotransmitters. Its alterations may consequently influence all these pathways that contribute to neuronal hyper-excitability and mirrored neuroinflammation in epilepsy and similarly other neurological conditions. Indeed, pre- and clinical studies support the role of the microbiome in pathogenesis, seizure modulation and responses to treatment in epilepsy. Up to now, researchers have focussed attention above all on the brain to develop antiepileptic treatments, but considering the microbiome, could extend our possibilities for developing novel therapies in the future. We provide here a comprehensive overview of the available data on the potential role of gut microbiota in the physiopathology and therapy of epilepsy and the supposed underlying mechanisms.
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Affiliation(s)
- Carmen De Caro
- Science of Health Department, School of Medicine, University Magna Graecia, Catanzaro, Italy
| | - Luigi Francesco Iannone
- Science of Health Department, School of Medicine, University Magna Graecia, Catanzaro, Italy
| | - Rita Citraro
- Science of Health Department, School of Medicine, University Magna Graecia, Catanzaro, Italy
| | - Pasquale Striano
- Paediatric Neurology and Muscular Diseases Unit, DINOGMI-Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, IRCCS "G. Gaslini" Institute, Genova, Italy
| | - Giovambattista De Sarro
- Science of Health Department, School of Medicine, University Magna Graecia, Catanzaro, Italy
| | - Andrew Constanti
- Department of Pharmacology, UCL School of Pharmacy, 29/39 Brunswick Square, London, United Kingdom
| | - John F Cryan
- UK.APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Emilio Russo
- Science of Health Department, School of Medicine, University Magna Graecia, Catanzaro, Italy.
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Hypoallergenic diet may control refractory epilepsy in allergic children: A quasi experimental study. Sci Rep 2019; 9:6875. [PMID: 31053764 PMCID: PMC6499767 DOI: 10.1038/s41598-019-43252-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 04/18/2019] [Indexed: 11/12/2022] Open
Abstract
Recent data has suggested a definitive role for inflammatory processes in the pathophysiology of epilepsy. In this study we hypothesized that food allergies, as chronic inflammatory processes, underlie the pathophysiology of refractory idiopathic epilepsy and investigated whether food elimination diets may assist in managing refractory epilepsy. The study was conducted on 34 patients up to 16 years of age with refractory convulsions who attended the Allergy Outpatient Clinic, Mofid Children Hospital between 2015 and 2016 with youngest and oldest participants at ages of 3 months and 16 years old, respectively. The participants were categorized into three groups according to the results of skin prick test and serum specific IgE measurements. Elimination diets were instituted for the patients with non IgE-mediated and mixed food allergies. The study was conducted for a period of 12 weeks. The participants were assessed for at least 50% reduction in number of seizures following the intervention. There was a significant reduction in number of seizures (p < 0.001) following the intervention. Seventeen patients (50%) did not experience any seizures after 8 weeks of treatment and 12 patients (35%) had a significant (51–99%) decrease in the number of their seizures. Five patients did not show any changes in their daily seizure frequency. The obtained data suggest that food allergy may play a role in triggering refractory epilepsies and their adequate response to treatment. A trial of elimination diet showed more than 50% seizure reduction in more than 85% of the children studied. However, we believe these results are preliminary and they motivate a fully controlled study in the future.
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Lewis ML, Kesler M, Candy SA, Rho JM, Pittman QJ. Comorbid epilepsy in autism spectrum disorder: Implications of postnatal inflammation for brain excitability. Epilepsia 2018; 59:1316-1326. [PMID: 29858515 DOI: 10.1111/epi.14440] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2018] [Indexed: 12/30/2022]
Abstract
OBJECTIVE In different cohorts, 5%-30% of individuals with autism spectrum disorder (ASD) also have epilepsy. The high co-occurrence of these disorders suggests that a common mechanistic link may exist. The underlying pathophysiology of this comorbidity remains unknown. To investigate the mechanism(s) involved in the pathogenesis of ASD and epilepsy, we developed and validated a novel mouse model that concurrently exhibits hallmark features of both disorders. METHODS We utilized inbred BTBR T+ Itpr3tf/J (BTBR) mice that exhibit the core behavioral characteristics of ASD (ie, impaired sociability, altered vocalizations, and restricted interests). BTBR mice received a lipopolysaccharide (LPS) or sterile saline injection at postnatal day (P)7, P14, or P21. Cytokine expression was analyzed for interleukin (IL)-1β, IL-10, IL-6, and tumor necrosis factor α in brain tissue of P7 and adult BTBR mice. Adult BTBR mice were behaviorally analyzed for seizure susceptibility, sociability, communication deficits, and motor stereotypies, and monitored using chronic video-electroencephalography (EEG). RESULTS Adult male and female BTBR mice treated at P7-P14 with LPS were more sensitive to pentylenetetrazol-induced seizures than saline-treated controls. ASD-like behaviors and hippocampal cytokine levels were unchanged between P7 LPS-treated BTBR mice and controls. EEG recordings from the dorsal hippocampus revealed a significant increase in number and frequency of seizures over the 4-week recording period (P60-P88) in BTBR mice postnatally treated with LPS at P7. These results indicate the presence of a comorbid epileptic phenotype in BTBR mice. SIGNIFICANCE These findings suggest that an early postnatal immune challenge can increase brain excitability in adult BTBR mice and reveal an underlying epilepsy phenotype. This novel animal model may enable the elucidation of specific molecular alterations that are associated with the concurrent presentation of ASD and epilepsy, which could facilitate the development of targeted therapies for individuals affected by this comorbidity.
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Affiliation(s)
- Megan Leigh Lewis
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Mitchell Kesler
- Departments of Pediatrics, Clinical Neurosciences, and Physiology and Pharmacology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Sydney A Candy
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jong M Rho
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Departments of Pediatrics, Clinical Neurosciences, and Physiology and Pharmacology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Quentin J Pittman
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Volumetric response of the adult brain to seizures depends on the developmental stage when systemic inflammation was induced. Epilepsy Behav 2018; 78:280-287. [PMID: 29128467 DOI: 10.1016/j.yebeh.2017.09.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 09/15/2017] [Accepted: 09/15/2017] [Indexed: 01/07/2023]
Abstract
Inflammation has detrimental influences on the developing brain including triggering the epileptogenesis. On the other hand, seizure episodes may induce inflammatory processes and further increase of brain excitability. The present study focuses on the problem whether transitory systemic inflammation during developmental period may have critical importance to functional and/or structural features of the adult brain. An inflammatory status was induced with lipopolysaccharide (LPS) in 6- or 30-day-old rats. Two-month-old rats which experienced the inflammation and untreated controls received injections of pilocarpine, and the intensity of their seizure behavior was rated during a 6-hour period. Three days thereafter, the animals were perfused; their brains were postfixed and subjected to magnetic resonance imaging (MRI) scans. Then, volumes of the brain and of its main regions were assessed. LPS injections alone performed at different developmental stages led to different changes in the volume of adult brain and also to different susceptibility to seizures induced in adulthood. Moreover, the LPS pretreatments modified different volumetric responses of the brain and of its regions to seizures. The responses showed strong inverse correlations with the intensity of seizures but exclusively in rats treated with LPS on postnatal day 30. It could be concluded that generalized inflammation elicited at developmental stages may have strong age-dependent effects on the adult brain regarding not only its susceptibility to action of a seizuregenic agent but also its volumetric reactivity to seizures.
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Gharedaghi MH, Rahimian R, Dehpour AR, Yousefzadeh-Fard Y, Mohammadi-Farani A. Dinitrobenzene sulphonic acid-induced colitis impairs spatial recognition memory in mice: roles of N-methyl D-aspartate receptors and nitric oxide. Psychopharmacology (Berl) 2015; 232:3081-90. [PMID: 25971874 DOI: 10.1007/s00213-015-3950-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 04/22/2015] [Indexed: 12/21/2022]
Abstract
RATIONALE Many peripheral diseases are associated with a decline in cognitive function. In this regard, there have been reports of patients with inflammatory bowel disease and an otherwise unexplained memory impairment. OBJECTIVES We sought to assess the memory performance of mice with colitis. We also investigated the roles of N-methyl D-aspartate (NMDA) receptors and nitric oxide (NO) as possible mediators of colitis-induced amnesia. METHODS To induce colitis, male NMRI mice were intrarectally injected with a solution containing dinitrobenzene sulfonic acid (DNBS; 4 mg in 100 μl) under anesthesia. Three days after intrarectal DNBS instillation, spatial recognition and associative memories were assessed by the Y-maze and passive avoidance tasks, respectively. The NMDA antagonists, MK-801 and memantine, and the inducible NO synthase (iNOS) inhibitor, aminoguanidine, were injected intraperitoneally 45 min before the Y-maze task. RESULTS Induction of colitis by DNBS impaired spatial recognition memory in the Y-maze task but had no effect on step through latencies in the passive avoidance test. Colitis-induced amnesia was reversed by administering specific doses of MK-801 and memantine (30 μg/kg and 1 mg/kg, respectively) suggesting dysregulated NMDA receptor activation as an underlying mechanism. No effect was seen with lower and higher doses of these drugs, resulting in a bell-shaped dose response curve. Colitis-induced amnesia was also inhibited by aminoguanidine (50 mg/kg), implicating a role for iNOS activation and neuroinflammation in this phenomenon. CONCLUSION DNBS-induced colitis impairs memory through NMDA receptor overstimulation and NO overproduction.
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Affiliation(s)
- Mohammad Hadi Gharedaghi
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, PO Box 13145-784, Tehran, Iran
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The association between seizure predisposition and inflammation in a rat model of fatty liver disease. Neurol Sci 2014; 35:1441-6. [DOI: 10.1007/s10072-014-1778-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 03/27/2014] [Indexed: 12/18/2022]
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Chen YH, Kuo TT, Chu MT, Ma HI, Chiang YH, Huang EYK. Postnatal systemic inflammation exacerbates impairment of hippocampal synaptic plasticity in an animal seizure model. Neuroimmunomodulation 2013; 20:223-32. [PMID: 23736043 DOI: 10.1159/000348440] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 01/25/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To investigate the effects of systemic inflammation in the critical postnatal stages on neurophysiological actions of immune processes and neural plasticity in adult rats after kainic acid (KA)-induced seizures. METHODS To determine changes in hippocampal synaptic plasticity after postnatal central nervous system inflammatory responses and seizure attacks, we performed intraperitoneal injections of lipopolysaccharide (LPS) in postnatal Sprague Dawley rats on day 14 (P14) to induce central nervous system inflammation. We then used a KA tail vein injection on P35 to induce seizure attacks. We compared the variability in synaptic plasticity in the hippocampal Schaffer collateral-CA1 region of seizure animals with or without LPS-induced inflammation preconditioning. RESULTS P14 injection of LPS increased susceptibility to seizures, while treatment with KA on P35 induced seizures. Long-term potentiation (LTP) of the Schaffer collateral-CA1 region was impaired in seizure animals, and this effect was more pronounced in the P14 LPS injection group. Fluoro-Jade staining revealed an increase in degenerated hippocampal CA1 pyramidal cells in the P14 LPS injection group. Cytokine expression in the hippocampus in the pre-, peri- and postictus periods was greater in P14 LPS rats than in saline-treated rats. CONCLUSIONS Intraperitoneal LPS injection on P14 induces higher cytokine secretion after KA-induced seizures, enhancing neuronal excitability, shortening seizure onset time and exacerbating neuronal degeneration and impairment of LTP formation in the hippocampal Schaffer collateral-CA1 region. Central nervous system inflammation during critical stages of childhood development could disrupt the balance needed for neurophysiological actions of immune processes, producing direct, pernicious effects on memory, neural plasticity and neurogenesis into adulthood.
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Affiliation(s)
- Yuan-Hao Chen
- Department of Neurological Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC
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Contributions of peripheral inflammation to seizure susceptibility: cytokines and brain excitability. Epilepsy Res 2009; 89:34-42. [PMID: 19804959 DOI: 10.1016/j.eplepsyres.2009.09.004] [Citation(s) in RCA: 219] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Revised: 09/04/2009] [Accepted: 09/07/2009] [Indexed: 01/23/2023]
Abstract
Inflammation is an important factor in the pathophysiology of seizure generation and epileptogenesis. While the role of CNS inflammation is well acknowledged as an important factor in seizure pathophysiology, less is known about the role of peripheral inflammation. Systemic inflammation induces a mirror inflammatory response in the brain that might have transient or long-term effects on seizure susceptibility. The focus of our laboratory research is the study of the interaction of systemic inflammatory events with neuronal excitability and seizure susceptibility. In this paper we provide a review of our findings and discuss possible mechanisms.
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Microglial activation and TNFalpha production mediate altered CNS excitability following peripheral inflammation. Proc Natl Acad Sci U S A 2008; 105:17151-6. [PMID: 18955701 DOI: 10.1073/pnas.0806682105] [Citation(s) in RCA: 309] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Peripheral inflammation leads to a number of centrally mediated physiological and behavioral changes. The underlying mechanisms and the signaling pathways involved in these phenomena are not yet well understood. We hypothesized that peripheral inflammation leads to increased neuronal excitability arising from a CNS immune response. We induced inflammation in the gut by intracolonic administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS) to adult male rats. To examine the excitability of the brain in vivo, we administered pentylenetetrazole (PTZ; a GABAergic antagonist) intravenously to evoke clonic seizures. Rats treated with TNBS showed increased susceptibility to PTZ seizures that was strongly correlated with the severity and progression of intestinal inflammation. In vitro hippocampal slices from inflamed, TNBS-treated rats showed increased spontaneous interictal burst firing following application of 4-aminopyridine, indicating increased intrinsic excitability. The TNBS-treated rats exhibited a marked, reversible inflammatory response within the hippocampus, characterized by microglial activation and increases in tumor necrosis factor alpha (TNFalpha) levels. Central antagonism of TNFalpha using a monoclonal antibody or inhibition of microglial activation by i.c.v. injection of minocycline prevented the increase in seizure susceptibility. Moreover, i.c.v. infusion of TNFalpha in untreated rats for 4 days also increased seizure susceptibility and thus mimicked the changes in seizure threshold observed with intestinal inflammation. Our finding of a microglia-dependent TNFalpha-mediated increase in CNS excitability provides insight into potential mechanisms underlying the disparate neurological and behavioral changes associated with chronic inflammation.
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Rao RS, Medhi B, Saikia UN, Arora SK, Toor JS, Khanduja KL, Pandhi P. Experimentally induced various inflammatory models and seizure: understanding the role of cytokine in rat. Eur Neuropsychopharmacol 2008; 18:760-7. [PMID: 18701263 DOI: 10.1016/j.euroneuro.2008.06.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2008] [Revised: 06/12/2008] [Accepted: 06/17/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND The mechanism of epileptogenesis is not well established. There is higher incidence of seizures among patients with chronic inflammatory disease. Cytokines are rapidly induced in the brain after a variety of stimuli including inflammation. Aim of this study was to produce various inflammatory models and seizure to understand the role of TNFalpha in above mentioned models. MATERIALS AND METHODS A total of 54 male rats were included in the study. Animals were divided into 3 groups of colitis, arthritis, and cotton wool granuloma. Each group had 3 subgroups of control, model and treatment. At the end of 3 days in colitis, 17 days in arthritis and 7 days in cotton wool granuloma groups a subconvulsive dose of PTZ (40 mg/kg i.p) was injected to note seizure onset and seizure score. Brain samples were subjected to DNA fragmentation testing. Presence of inflammation was confirmed by morphology and histology. Plasma and brain TNFalpha levels were measured. RESULTS The models of colitis, arthritis and CWG were effectively produced as evidenced by morphology and histology scores (p<0.001). Seizure onset was reduced and grade was increased (p<0.001). Thalidomide reduced the morphological, histological (p<0.002), DNA fragmentation and seizure grade (p<0.001) while increased seizure onset (p<0.001) in the arthritis group. TNFalpha levels in both plasma and brain were reduced following thalidomide treatment (p<0.002) in arthritis group. There were no significant findings in colitis or cotton wool granuloma groups. CONCLUSION Inflammation was associated with decreased threshold to PTZ induced seizure. Thalidomide is effective in reducing the extent of arthritis as well as reducing the seizure scoring and increasing seizure onset in the adjuvant arthritis group. Thalidomide was also effective in reducing TNFalpha levels thus contributing to its antiepileptic activity.
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Affiliation(s)
- R S Rao
- Department of Pharmacology, Postgraduate Institute of Medical Education & Research, Chandigarh PGIMER, Chandigarh, India
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Bermejo PE, Burgos A. [Neurological complications of inflammatory bowel disease]. Med Clin (Barc) 2008; 130:666-75. [PMID: 18501131 DOI: 10.1157/13120693] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although ulcerative colitis and Crohn's disease have traditionally been considered to be inflammatory diseases limited to the gastrointestinal tract, it has been shown that both pathologies are frequently accompanied by various extraintestinal disorders. There is an increasing evidence that they may also manifest in the nervous system, including the peripheral and the central parts. Although some of these neurological complications have been known for a long time, such as cerebrovascular disease, vasculitis and autoinmune processes including neuropathies and cerebral demyelination, others have been recently described. With the exception of some of this complications such as the thromboembolism, evidence for a casual relationship relies merely on single case reports or case series. In this article, we try to review the existing evidence on neurological manifestations of both variants of inflammatory bowel disease.
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Affiliation(s)
- Pedro Emilio Bermejo
- Servicio de Neurología, Hospital Universitario Puerta de Hierro, Madrid, España.
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Abstract
This paper is the 27th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over 30 years of research. It summarizes papers published during 2004 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, USA.
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