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Gulino M, Santos SD, Pêgo AP. Biocompatibility of Platinum Nanoparticles in Brain ex vivo Models in Physiological and Pathological Conditions. Front Neurosci 2022; 15:787518. [PMID: 34975386 PMCID: PMC8714788 DOI: 10.3389/fnins.2021.787518] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/26/2021] [Indexed: 12/22/2022] Open
Abstract
Platinum nanoparticles (PtNPs) have unique physico-chemical properties that led to their use in many branches of medicine. Recently, PtNPs gathered growing interest as delivery vectors for drugs, biosensors and as surface coating on chronically implanted biomedical devices for improving electrochemical properties. However, there are contradictory statements about their biocompatibility and impact on target organs such as the brain tissue, where these NPs are finding many applications. Furthermore, many of the reported studies are conducted in homeostasis conditions and, consequently, neglect the impact of the pathologic conditions on the tissue response. To expand our knowledge on the effects of PtNPs on neuronal and glial cells, we investigated the acute effects of monodisperse sodium citrate-coated PtNPs on rat organotypic hippocampal cultures in physiological or neuronal excitotoxic conditions induced by kainic acid (KA). The cellular responses of the PtNPs were evaluated through cytotoxic assays and confocal microscopy analysis. To mimic a pathologic scenario, 7-day organotypic hippocampal cultures were exposed to KA for 24 h. Subsequently, PtNPs were added to each slice. We show that incubation of the slices with PtNPs for 24 h, does not severely impact cell viability in normal conditions, with no significant differences when comparing the dentate gyrus (DG), as well as CA3 and CA1 pyramidal cell layers. Such effects are not exacerbated in KA-treated slices, where the presence of PtNPs does not cause additional neuronal propidium iodide (PI) uptake in CA3 and CA1 pyramidal cell layers. However, PtNPs cause microglial cell activation and morphological alterations in CA3 and DG regions indicating the establishment of an inflammatory reaction. Morphological analysis revealed that microglia acquire activated ameboid morphology with loss of ramifications, as a result of their response to PtNPs contact. Surprisingly, this effect is not increased in pathological conditions. Taken together, these results show that PtNPs cause microglia alterations in short-term studies. Additionally, there is no worsening of the tissue response in a neuropathological induced scenario. This work highlights the need of further research to allow for the safe use of PtNPs. Also, it supports the demand of the development of novel and more biocompatible NPs to be applied in the brain.
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Affiliation(s)
- Maurizio Gulino
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,FEUP - Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
| | - Sofia Duque Santos
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - Ana Paula Pêgo
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,FEUP - Faculdade de Engenharia da Universidade do Porto, Porto, Portugal.,ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Wang YF, Luo Y, Hou GL, He RJ, Zhang HY, Yi YL, Zhang Y, Cui ZQ. Pretreatment with Methylene Blue Protects Against Acute Seizure and Oxidative Stress in a Kainic Acid-Induced Status Epilepticus Model. Med Sci Monit 2021; 27:e933469. [PMID: 34628461 PMCID: PMC8513497 DOI: 10.12659/msm.933469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background The aim of the present study was to investigate the potential anticonvulsant effect of methylene blue (MB) in a kainic acid (KA)-induced status epilepticus (SE) model. The effects of MB on levels of oxidative stress and glutamate (Glu) also were explored. Material/Methods Sixty C57BL/6 mice were randomly divided into 5 equal-sized groups: (1) controls; (2) KA; (3) MB 0.5 mg/kg+KA; (4) MB 1 mg/kg+KA; and (5) vehicle+KA. The SE model was established by intra-amygdala microinjection of KA. Behavioral observations and simultaneous electroencephalographic records of the seizures in different groups were analyzed to determine the potential anticonvulsant effect of MB. The influences of MB on oxidative stress markers and glutamate were also detected to explore the possible mechanism. Results MB afforded clear protection against KA-induced acute seizure, as measured by the delayed latency of onset of generalized seizures and SE, decreased percentage of SE, and increased survival rate in mice with acute epilepsy. MB markedly increased the latency to first onset of epileptiform activity and decreased the average duration of epileptiform events, as well as the percentage of time during which the epileptiform activity occurred. Administration of MB prevented KA-induced deterioration of oxidative stress markers and Glu. Conclusions MB is protective against acute seizure in SE. This beneficial effect may be at least partially related to its potent antioxidant ability and influence on Glu level.
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Affiliation(s)
- Yong-Feng Wang
- Department of Neurosurgery, Affiliated Hospital of Hebei University of Engineering, Handan, Hebei, China (mainland)
| | - Yan Luo
- Department of Reproductive Genetic, Hebei General Hospital, Shijiazhuang, Hebei, China (mainland)
| | - Gao-Lei Hou
- Department of Neurosurgery, Affiliated Hospital of Hebei University of Engineering, Handan, Hebei, China (mainland)
| | - Rui-Jing He
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, Hebei, China (mainland)
| | - Hao-Yun Zhang
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, Hebei, China (mainland)
| | - Yan-Li Yi
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, Hebei, China (mainland)
| | - Ying Zhang
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, Hebei, China (mainland)
| | - Zhi-Qiang Cui
- Department of Breast Surgery, Affiliated Hospital of Hebei University of Engineering, Handan, Hebei, China (mainland)
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Gulino M, Kim D, Pané S, Santos SD, Pêgo AP. Tissue Response to Neural Implants: The Use of Model Systems Toward New Design Solutions of Implantable Microelectrodes. Front Neurosci 2019; 13:689. [PMID: 31333407 PMCID: PMC6624471 DOI: 10.3389/fnins.2019.00689] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/18/2019] [Indexed: 01/28/2023] Open
Abstract
The development of implantable neuroelectrodes is advancing rapidly as these tools are becoming increasingly ubiquitous in clinical practice, especially for the treatment of traumatic and neurodegenerative disorders. Electrodes have been exploited in a wide number of neural interface devices, such as deep brain stimulation, which is one of the most successful therapies with proven efficacy in the treatment of diseases like Parkinson or epilepsy. However, one of the main caveats related to the clinical application of electrodes is the nervous tissue response at the injury site, characterized by a cascade of inflammatory events, which culminate in chronic inflammation, and, in turn, result in the failure of the implant over extended periods of time. To overcome current limitations of the most widespread macroelectrode based systems, new design strategies and the development of innovative materials with superior biocompatibility characteristics are currently being investigated. This review describes the current state of the art of in vitro, ex vivo, and in vivo models available for the study of neural tissue response to implantable microelectrodes. We particularly highlight new models with increased complexity that closely mimic in vivo scenarios and that can serve as promising alternatives to animal studies for investigation of microelectrodes in neural tissues. Additionally, we also express our view on the impact of the progress in the field of neural tissue engineering on neural implant research.
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Affiliation(s)
- Maurizio Gulino
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- FEUP – Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
| | - Donghoon Kim
- Multi-Scale Robotics Lab (MSRL), Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Zurich, Switzerland
| | - Salvador Pané
- Multi-Scale Robotics Lab (MSRL), Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Zurich, Switzerland
| | - Sofia Duque Santos
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - Ana Paula Pêgo
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- FEUP – Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
- ICBAS – Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Noè F, Cattalini A, Vila Verde D, Alessi C, Colciaghi F, Figini M, Zucca I, de Curtis M. Epileptiform activity contralateral to unilateral hippocampal sclerosis does not cause the expression of brain damage markers. Epilepsia 2019; 60:1184-1199. [PMID: 31111475 DOI: 10.1111/epi.15611] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/24/2019] [Accepted: 04/24/2019] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Patients with epilepsy often ask if recurrent seizures harm their brain and aggravate their epileptic condition. This crucial question has not been specifically addressed by dedicated experiments. We analyze here if intense bilateral seizure activity induced by local injection of kainic acid (KA) in the right hippocampus produces brain damage in the left hippocampus. METHODS Adult guinea pigs were bilaterally implanted with hippocampal electrodes for continuous video-electroencephalography (EEG) monitoring. Unilateral injection of 1 μg KA in the dorsal CA1 area induced nonconvulsive status epilepticus (ncSE) characterized by bilateral hippocampal seizure discharges. This treatment resulted in selective unilateral sclerosis of the KA-injected hippocampus. Three days after KA injection, the animals were killed, and the brains were submitted to ex vivo magnetic resonance imaging (MRI) and were processed for immunohistochemical analysis. RESULTS During ncSE, epileptiform activity was recorded for 27.6 ± 19.1 hours in both the KA-injected and contralateral hippocampi. Enhanced T1-weighted MR signal due to gadolinium deposition, mean diffusivity reduction, neuronal loss, gliosis, and blood-brain barrier permeability changes was observed exclusively in the KA-injected hippocampus. Despite the presence of a clear unilateral hippocampal sclerosis at the site of KA injection, no structural alterations were detected by MR and immunostaining analysis performed in the hippocampus contralateral to KA injection 3 days and 2 months after ncSE induction. Fluoro-Jade and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining at the same time points confirmed the absence of degenerating cells in the hippocampi contralateral to KA injection. SIGNIFICANCE We demonstrate that intense epileptiform activity during ncSE does not cause obvious brain damage in the hippocampus contralateral to unilateral hippocampal KA injection. These findings argue against the hypothesis that epileptiform activity per se contributes to focal brain injury in previously undamaged cortical regions.
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Affiliation(s)
- Francesco Noè
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | | | - Diogo Vila Verde
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Camilla Alessi
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Francesca Colciaghi
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Matteo Figini
- Scientific Direction, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Ileana Zucca
- Scientific Direction, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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Gargouri B, Yousif NM, Bouchard M, Fetoui H, Fiebich BL. Inflammatory and cytotoxic effects of bifenthrin in primary microglia and organotypic hippocampal slice cultures. J Neuroinflammation 2018; 15:159. [PMID: 29793499 PMCID: PMC5968622 DOI: 10.1186/s12974-018-1198-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/10/2018] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Pyrethroids, such as bifenthrin (BF), are among the most widely used class of insecticides that pose serious risks to human and wildlife health. Pyrethroids are proposed to affect astrocytic functions and to cause neuron injury in the central nervous system (CNS). Microglia are key cells involved in innate immune responses in the CNS, and microglia activation has been linked to inflammation and neurotoxicity. However, little information is known about the effects of BF-induced toxicity in primary microglial cells as well as in organotypic hippocampal slice cultures (OHSCs). METHODS Oxidative stress and inflammatory responses induced by BF were evaluated in primary microglial cells and OHSCs incubated with different concentrations of BF (1-20 μM) for 4 and 24 h. mRNA and protein synthesis of cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), nuclear erythroid-2 like factor-2 (Nrf-2), and microsomal prostaglandin synthase-1 (mPGES-1) was also studied by qPCR and Western blot. Cell viability was analyzed by MTT-tetrazolio (MTT) and lactate dehydrogenase (LDH) assays. Neurotoxicity in OHSCs was analyzed by propidium iodide (PI) staining and confocal microscopy. RESULTS Exposure of microglial cells to BF for 24 h resulted in a dose-dependent reduction in the number of viable cells. At sub-cytotoxic concentrations, BF increased reactive oxygen species (ROS), TNF-alpha synthesis, and prostaglandin E2 (PGE2) production, at both 4- and 24-h time points, respectively. Furthermore, BF incubation decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities and increased lipid peroxidation, protein oxidation, and H2O2 formation. In addition, BF significantly induced protein synthesis and mRNA expression of oxidative and inflammatory mediators after 4 and 24 h, including Nrf-2, COX-2, mPGES-1, and nuclear factor kappaB (NF-kappaB). A 24-h exposure of OHSCs to BF also increased neuronal death compared to untreated controls. Furthermore, depletion of microglia from OHSCs potently enhanced neuronal death induced by BF. CONCLUSIONS Overall, BF exhibited cytotoxic effects in primary microglial cells, accompanied by the induction of various inflammatory and oxidative stress markers including the Nrf-2/COX-2/mPGES-1/NF-kappaB pathways. Moreover, the study provided evidence that BF induced neuronal death in OHSCs and suggests that microglia exert a protective function against BF toxicity.
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Affiliation(s)
- Brahim Gargouri
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Laboratory of Toxicology-Microbiology and Environmental Health (17ES06), Sciences Faculty of Sfax, University of Sfax, BP1171, 3000 Sfax, Tunisia
- Laboratory of Translational Psychiatry, Department of Psychiatry and Psychotherapy, Medical Center Faculty of Medicine, University of Freiburg, Hauptstrasse 5, 79104 Freiburg, Germany
| | - Nizar M. Yousif
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Michèle Bouchard
- Department of Environmental and Occupational Health, Toxicological Risk Assessment and Management, University of Montreal, Roger-Gaudry Building, U424, Main Station, Montreal, P.O. Box 6128, Montreal, Quebec H3C 3J7 Canada
| | - Hamadi Fetoui
- Laboratory of Toxicology-Microbiology and Environmental Health (17ES06), Sciences Faculty of Sfax, University of Sfax, BP1171, 3000 Sfax, Tunisia
| | - Bernd L. Fiebich
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Rojas A, Jiang J, Ganesh T, Yang MS, Lelutiu N, Gueorguieva P, Dingledine R. Cyclooxygenase-2 in epilepsy. Epilepsia 2013; 55:17-25. [PMID: 24446952 DOI: 10.1111/epi.12461] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2013] [Indexed: 12/14/2022]
Abstract
Epilepsy is one of the more prevalent neurologic disorders in the world, affecting approximately 50 million people of different ages and backgrounds. Epileptic seizures propagating through both lobes of the forebrain can have permanent debilitating effects on a patient's cognitive and somatosensory brain functions. Epilepsy, defined by the sporadic occurrence of spontaneous recurrent seizures (SRS), is often accompanied by inflammation of the brain. Pronounced increases in the expression of key inflammatory mediators (e.g., interleukin -1β [IL-1β], tumor necrosis factor alpha [TNFα], cyclooxygenase-2 [COX-2], and C-X-C motif chemokine 10 [CXCL10]) after seizures may cause secondary damage in the brain and increase the likelihood of repetitive seizures. The COX-2 enzyme is induced rapidly during seizures. The increased level of COX-2 in specific areas of the epileptic brain can help to identify regions of seizure-induced brain inflammation. A good deal of effort has been expended to determine whether COX-2 inhibition might be neuroprotective and represent an adjunct therapeutic strategy along with antiepileptic drugs used to treat epilepsy. However, the effectiveness of COX-2 inhibitors on epilepsy animal models appears to depend on the timing of administration. With all of the effort placed on making use of COX-2 inhibitors as therapeutic agents for the treatment of epilepsy, inflammation, and neurodegenerative diseases there has yet to be a selective and potent COX-2 inhibitor that has shown a clear therapeutic outcome with acceptable side effects.
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Affiliation(s)
- Asheebo Rojas
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, U.S.A
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Experimental models of status epilepticus and neuronal injury for evaluation of therapeutic interventions. Int J Mol Sci 2013; 14:18284-318. [PMID: 24013377 PMCID: PMC3794781 DOI: 10.3390/ijms140918284] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 07/31/2013] [Accepted: 08/09/2013] [Indexed: 01/19/2023] Open
Abstract
This article describes current experimental models of status epilepticus (SE) and neuronal injury for use in the screening of new therapeutic agents. Epilepsy is a common neurological disorder characterized by recurrent unprovoked seizures. SE is an emergency condition associated with continuous seizures lasting more than 30 min. It causes significant mortality and morbidity. SE can cause devastating damage to the brain leading to cognitive impairment and increased risk of epilepsy. Benzodiazepines are the first-line drugs for the treatment of SE, however, many people exhibit partial or complete resistance due to a breakdown of GABA inhibition. Therefore, new drugs with neuroprotective effects against the SE-induced neuronal injury and degeneration are desirable. Animal models are used to study the pathophysiology of SE and for the discovery of newer anticonvulsants. In SE paradigms, seizures are induced in rodents by chemical agents or by electrical stimulation of brain structures. Electrical stimulation includes perforant path and self-sustaining stimulation models. Pharmacological models include kainic acid, pilocarpine, flurothyl, organophosphates and other convulsants that induce SE in rodents. Neuronal injury occurs within the initial SE episode, and animals exhibit cognitive dysfunction and spontaneous seizures several weeks after this precipitating event. Current SE models have potential applications but have some limitations. In general, the experimental SE model should be analogous to the human seizure state and it should share very similar neuropathological mechanisms. The pilocarpine and diisopropylfluorophosphate models are associated with prolonged, diazepam-insensitive seizures and neurodegeneration and therefore represent paradigms of refractory SE. Novel mechanism-based or clinically relevant models are essential to identify new therapies for SE and neuroprotective interventions.
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Sobayo T, Mogul DJ. Rapid onset of a kainate-induced mirror focus in rat hippocampus is mediated by contralateral AMPA receptors. Epilepsy Res 2013; 106:35-46. [DOI: 10.1016/j.eplepsyres.2013.03.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 02/28/2013] [Accepted: 03/25/2013] [Indexed: 11/28/2022]
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Epigenetic Mechanisms Shape the Biological Response to Trauma and Risk for PTSD: A Critical Review. Nurs Res Pract 2013; 2013:417010. [PMID: 23710355 PMCID: PMC3654332 DOI: 10.1155/2013/417010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 03/24/2013] [Indexed: 12/30/2022] Open
Abstract
Posttraumatic stress disorder (PTSD) develops in approximately one-quarter of trauma-exposed individuals, leading us and others to question the mechanisms underlying this heterogeneous response to trauma. We suggest that the reasons for the heterogeneity relate to a complex interaction between genes and the environment, shaping each individual's recovery trajectory based on both historical and trauma-specific variables. Epigenetic modifications provide a unique opportunity to elucidate how preexisting risk factors may contribute to PTSD risk through changes in the methylation of DNA. Preexisting risks for PTSD, including depression, stress, and trauma, result in differential DNA methylation of endocrine genes, which may then result in a different biological responses to trauma and subsequently a greater risk for PTSD onset. Although these relationships are complex and currently inadequately described, we provide a critical review of recent studies to examine how differences in genetic and proteomic biomarkers shape an individual's vulnerability to PTSD development, thereby contributing to a heterogeneous response to trauma.
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Morin-Brureau M, De Bock F, Lerner-Natoli M. Organotypic brain slices: a model to study the neurovascular unit micro-environment in epilepsies. Fluids Barriers CNS 2013; 10:11. [PMID: 23391266 PMCID: PMC3605299 DOI: 10.1186/2045-8118-10-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 01/28/2013] [Indexed: 12/22/2022] Open
Abstract
Background It is now recognized that the neuro-vascular unit (NVU) plays a key role in several neurological diseases including epilepsy, stroke, Alzheimer’s disease, multiple sclerosis and the development of gliomas. Most of these disorders are associated with NVU dysfunction, due to overexpression of inflammatory factors such as vascular endothelial growth factor (VEGF). Various in vitro models have been developed previously to study the micro-environment of the blood–brain barrier (BBB). However none of these in vitro models contained a complete complement of NVU cells, nor maintained their interactions, thus minimizing the influence of the surrounding tissue on the BBB development and function. The organotypic hippocampal culture (OHC) is an integrative in vitro model that allows repeated manipulations over time to further understand the development of cell circuits or the mechanisms of brain diseases. Methods/design OHCs were cultured from hippocampi of 6–7 day-old Sprague Dawley rats. After 2 weeks in culture, seizures were induced by application of kainate or bicuculline into culture medium. The regulation of BBB integrity under physiological and pathological conditions was evaluated by immunostaining of the main tight junction (TJ) proteins and of the basal membrane of microvessels. To mimic or prevent BBB disassembly, we used diverse pro- or anti-angiogenic treatments. Discussion This study demonstrates that NVU regulation can be investigated using OHCs. We observed in this model system an increase in vascularization and a down-regulation of TJ proteins, similar to the vascular changes described in a chronic focus of epileptic patients, and in rodent models of epilepsy or inflammation. We observed that Zonula occludens-1 (ZO-1) protein disappeared after seizures associated with neuronal damage. In these conditions, the angiopoeitin-1 system was down-regulated, and the application of r-angiopoeitin-1 allowed TJ re-assembly. This article demonstrates that organotypic culture is a useful model to decipher the links between epileptic activity and vascular damage, and also to investigate NVU regulation in diverse neurological disorders.
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Affiliation(s)
- Mélanie Morin-Brureau
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Université Montpellier 1, 2, Montpellier, France.
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