An in vitro seizure model from human hippocampal slices using multi-electrode arrays

Hsiao, Min-Chi; Yu, Pen-Ning; Song, Dong; Liu, Charles Y.; Heck, Christianne; Millett, David; Berger, Theodore W.

doi:10.1016/j.jneumeth.2014.09.010

Cited by 19 publications

(21 citation statements)

References 27 publications

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“…Slices were kept in culture for 7 d before performing the experiments. For induction of excitotoxicity, hippocampal slices were treated with media containing 50 μM NMDA at day in vitro 7 for 4 h; another batch of slices were then placed in fresh culture medium for another 24 h. For KA experiments, hippocampal slices were treated with media containing 1 mM KA (Sigma) for 6 h. For ATP experiments, hippocampal slices were treated with media containing 300 μM and 1 mM ATP (Sigma) for 4 h. For experiments with the epileptogenic cocktail, hippocampal slices were treated for 1 h with either vehicle (oxygenated (95% O 2 , 5% CO 2 ) ACSF, pH 7.4, containing 124 mM NaCl, 25 mM NaHCO 3 , 1.25 mM NaH 2 PO 4 , 2.5 mM KCl, 2.5 mM CaCl 2 , 1.3 mM MgCl 2 , and 10 mM D-glucose) or proepileptogenic cocktail (ACSF, with high K + (8 mM), low Mg 2+ (0.25 mM) and 4-AP (100 μM)) [ 84 ]. PI (5 μg/ml, Sigma) was added to the cultures in the last hour of the treatment.…”

Section: Methodsmentioning

confidence: 99%

“…Slices were allowed to recover for at least 1 h and were then transferred to a 37ºC chamber with continuous flow (1 mL/min) of oxygenated ACSF. To induce epileptiform activity, cells were perfused with high K + (8 mM), low Mg 2+ (0.25 mM) and 4-AP (100 μM) [ 84 ]. Extracellular field potential recording were performed in the CA1 pyramidal layer to monitor epileptiform activity, using glass electrodes (1 MΩ) filled with aCSF.…”

Section: Methodsmentioning

confidence: 99%

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Neuronal Hyperactivity Disturbs ATP Microgradients, Impairs Microglial Motility, and Reduces Phagocytic Receptor Expression Triggering Apoptosis/Microglial Phagocytosis Uncoupling

et al. 2016

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Phagocytosis is essential to maintain tissue homeostasis in a large number of inflammatory and autoimmune diseases, but its role in the diseased brain is poorly explored. Recent findings suggest that in the adult hippocampal neurogenic niche, where the excess of newborn cells undergo apoptosis in physiological conditions, phagocytosis is efficiently executed by surveillant, ramified microglia. To test whether microglia are efficient phagocytes in the diseased brain as well, we confronted them with a series of apoptotic challenges and discovered a generalized response. When challenged with excitotoxicity in vitro (via the glutamate agonist NMDA) or inflammation in vivo (via systemic administration of bacterial lipopolysaccharides or by omega 3 fatty acid deficient diets), microglia resorted to different strategies to boost their phagocytic efficiency and compensate for the increased number of apoptotic cells, thus maintaining phagocytosis and apoptosis tightly coupled. Unexpectedly, this coupling was chronically lost in a mouse model of mesial temporal lobe epilepsy (MTLE) as well as in hippocampal tissue resected from individuals with MTLE, a major neurological disorder characterized by seizures, excitotoxicity, and inflammation. Importantly, the loss of phagocytosis/apoptosis coupling correlated with the expression of microglial proinflammatory, epileptogenic cytokines, suggesting its contribution to the pathophysiology of epilepsy. The phagocytic blockade resulted from reduced microglial surveillance and apoptotic cell recognition receptor expression and was not directly mediated by signaling through microglial glutamate receptors. Instead, it was related to the disruption of local ATP microgradients caused by the hyperactivity of the hippocampal network, at least in the acute phase of epilepsy. Finally, the uncoupling led to an accumulation of apoptotic newborn cells in the neurogenic niche that was due not to decreased survival but to delayed cell clearance after seizures. These results demonstrate that the efficiency of microglial phagocytosis critically affects the dynamics of apoptosis and urge to routinely assess the microglial phagocytic efficiency in neurodegenerative disorders.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Neuronal Hyperactivity Disturbs ATP Microgradients, Impairs Microglial Motility, and Reduces Phagocytic Receptor Expression Triggering Apoptosis/Microglial Phagocytosis Uncoupling

et al. 2016

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“…Although the focus of this review is on models for drug-induced seizures, research using resected human tissue from patients with drug-resistant epilepsy should be considered. The possibilities for human tissue range from histopathological analyses, to modulation of SLE in drug-resistant tissue and the testing of novel anti-convulsant compounds and electrophysiological investigation ( Gabriel et al, 2004 ; Hsiao et al, 2015 ; Jones et al, 2016 ; Klaft et al, 2016 ). Furthermore, a number of methods are now available that increase the longevity of the resected tissue, enabling increased throughput of investigations ( Schwarz et al, 2017 ; Wickham et al, 2018 ).…”

Section: Current In Vitro Models Of Seizurementioning

confidence: 99%

In vitro Models for Seizure-Liability Testing Using Induced Pluripotent Stem Cells

et al. 2018

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The brain is the most complex organ in the body, controlling our highest functions, as well as regulating myriad processes which incorporate the entire physiological system. The effects of prospective therapeutic entities on the brain and central nervous system (CNS) may potentially cause significant injury, hence, CNS toxicity testing forms part of the “core battery” of safety pharmacology studies. Drug-induced seizure is a major reason for compound attrition during drug development. Currently, the rat ex vivo hippocampal slice assay is the standard option for seizure-liability studies, followed by primary rodent cultures. These models can respond to diverse agents and predict seizure outcome, yet controversy over the relevance, efficacy, and cost of these animal-based methods has led to interest in the development of human-derived models. Existing platforms often utilize rodents, and so lack human receptors and other drug targets, which may produce misleading data, with difficulties in inter-species extrapolation. Current electrophysiological approaches are typically used in a low-throughput capacity and network function may be overlooked. Human-derived induced pluripotent stem cells (iPSCs) are a promising avenue for neurotoxicity testing, increasingly utilized in drug screening and disease modeling. Furthermore, the combination of iPSC-derived models with functional techniques such as multi-electrode array (MEA) analysis can provide information on neuronal network function, with increased sensitivity to neurotoxic effects which disrupt different pathways. The use of an in vitro human iPSC-derived neural model for neurotoxicity studies, combined with high-throughput techniques such as MEA recordings, could be a suitable addition to existing pre-clinical seizure-liability testing strategies.

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“…It is therefore essential that the collection aCSF remains chilled and continually carbogenated (95% O2/5% CO2) to ensure that the tissue does not become anoxic. Portable chambers for the transport of prepared slices have been previously described (Hsiao et al, 2015;Kohling et al, 1996). It is also relatively straightforward to construct a system in which an icebox and a small (34L) disposable carbogen cylinder can be placed within a human tissue transportation box.…”

Section: Resection Collection and Preparation Of Human Epileptic Matmentioning

confidence: 99%

Human brain slices for epilepsy research: Pitfalls, solutions and future challenges

Jones

Silva

Whittaker

et al. 2016

Journal of Neuroscience Methods

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Increasingly, neuroscientists are taking the opportunity to use live human tissue obtained from elective neurosurgical procedures for electrophysiological studies in vitro. Access to this valuable resource permits unique studies into the network dynamics that contribute to the generation of pathological electrical activity in the human epileptic brain. Whilst this approach has provided insights into the mechanistic features of electrophysiological patterns associated with human epilepsy, it is not without technical and methodological challenges. This review outlines the main difficulties associated with working with epileptic human brain slices from the point of collection, through the stages of preparation, storage and recording. Moreover, it outlines the limitations, in terms of the nature of epileptic activity that can be observed in such tissue, in particular, the rarity of spontaneous ictal discharges, we discuss manipulations that can be utilised to induce such activity. In addition to discussing conventional electrophysiological techniques that are routinely employed in epileptic human brain slices, we review how imaging and multielectrode array recordings could provide novel insights into the network dynamics of human epileptogenesis. Acute studies in human brain slices are ultimately limited by the lifetime of the tissue so overcoming this issue provides increased opportunity for information gain. We review the literature with respect to organotypic culture techniques that may hold the key to prolonging the viability of this material. A combination of long-term culture techniques, viral transduction approaches and electrophysiology in human brain slices promotes the possibility of large scale monitoring and manipulation of neuronal activity in epileptic microcircuits.

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An in vitro seizure model from human hippocampal slices using multi-electrode arrays

Cited by 19 publications

References 27 publications

Neuronal Hyperactivity Disturbs ATP Microgradients, Impairs Microglial Motility, and Reduces Phagocytic Receptor Expression Triggering Apoptosis/Microglial Phagocytosis Uncoupling

Neuronal Hyperactivity Disturbs ATP Microgradients, Impairs Microglial Motility, and Reduces Phagocytic Receptor Expression Triggering Apoptosis/Microglial Phagocytosis Uncoupling

In vitro Models for Seizure-Liability Testing Using Induced Pluripotent Stem Cells

Human brain slices for epilepsy research: Pitfalls, solutions and future challenges

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