Prospects of levetiracetam as a neuroprotective drug against status epilepticus, traumatic brain injury, and stroke

A Comprehensive Stereology Method for Quantitative Evaluation of Neuronal Injury, Neurodegeneration, and Neurogenesis in Brain Disorders

Neuronal injury, neurodegeneration, and neuroanatomical changes are key pathological features of various neurological disorders, including epilepsy, stroke, traumatic brain injury, Parkinson's disease, autism, and Alzheimer's disease. Accurate quantification of neurons and interneurons in different brain regions is critical for understanding the progression of neurodegenerative disorders in animal models. Traditional scoring methods are often superficial, biased, and unreliable for evaluating neuropathology. Stereology, a quantitative tool that uses 3-dimensional visualization of cells, provides a robust protocol for evaluating neuronal injury and neurodegeneration. This article presents a comprehensive and optimized stereology protocol for unbiased quantification of neuronal injury, neurodegeneration, and neurogenesis in rat and mouse models. This protocol involves precise counting of injured neurons, surviving neurons, and interneurons through immunohistochemical processing of brain sections for NeuN(+) principal neurons, parvalbumin (PV+) interneurons, doublecortin (DCX+) newborn neurons, and Fluoro-Jade B (FJB+)-stained injured cells. Predefined hippocampal and amygdala regions were identified and analyzed using a Visiopharm stereology software-driven compound microscope. Cell density and absolute cell numbers were determined using the optical fractionation method. Our stereology protocol accurately estimated 1.5 million total NeuN(+) principal neurons and 0.05 million PV(+) interneurons in the rat hippocampus, as well as 1.2 million total principal neurons and 0.025 million interneurons in the mouse hippocampus. FJB(+) counting provided a quantitative index of damaged neurons, and the stereology of DCX(+) neurons demonstrated the extent of neurogenesis. Overall, this stereology protocol enables precise, accurate, and unbiased counting of total neurons in any brain region. This offers a reliable quantitative tool for studying neuronal injury and protection in various models of acute brain injury, neurotoxicity, and chronic neurological disorders. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Stereological quantification of principal neurons, interneurons, and immature neurons in the hippocampus in rat brain sections Basic Protocol 2: Stereological quantification of principal neurons, interneurons, and immature neurons in the hippocampus in mouse brain sections Basic Protocol 3: Stereological quantification of injured or necrotized cells stained with Fluoro-Jade B in the hippocampus and amygdala in rats Basic Protocol 4: Stereological quantification of injured or necrotized cells stained with Fluoro-Jade B in the hippocampus and amygdala regions in mice Basic Protocol 5: Brain fixation and histology processing Basic Protocol 6: Immunochemistry of principal neurons, interneurons, and newborn neurons Basic Protocol 7: Fluoro-Jade B staining of injured neurons.

The Primary Prevention of Poststroke Epilepsy in Patients With Middle Cerebral Artery Infarct: Protocol for a Randomized Controlled Trial

BACKGROUND

Poststroke epilepsy poses a significant clinical challenge for individuals recovering from strokes, leading to a less favorable long-term outlook and increased mortality rates. Existing studies have primarily concentrated on administering antiseizure or anticonvulsant treatments only after the onset of late-onset seizures, without intervening during the epileptogenesis phase following a stroke.

OBJECTIVE

This research protocol is designed to conduct a randomized controlled trial to assess whether the early, preventive introduction of low-dose antiepileptic drug therapy (levetiracetam [LEV] or perampanel [PER]) in patients who have experienced middle cerebral artery (MCA) infarction can reduce the risk of developing poststroke epilepsy (primary prevention).

METHODS

Participants with MCA infarction, either with or without reperfusion treatments, will be recruited and promptly receive preventive intervention within 72 hours of the stroke occurrence. These participants will be randomly assigned to receive either PER (4 mg per day), LEV (1000 mg per day), or a placebo that matches the active drugs. This treatment will continue for 12 weeks after allocation. Brain magnetic resonance imaging will be used to confirm the presence of MCA territory infarction, and an electroencephalography will be used to ensure the absence of epileptiform discharges or electrographic seizures at the time of the stroke. All participants will undergo follow-up assessments for 72 weeks after allocation.

RESULTS

The primary outcome under evaluation will be the incidence of poststroke epilepsy in the 3 groups following the 18-month study period. Secondary outcomes will encompass the time to the occurrence of the first seizure, the severity of seizures, any treatment-related adverse events, and the modified Rankin scale score at 3 and 18 months. Exploratory outcomes will involve comparing the effectiveness and safety of PER and LEV.

CONCLUSIONS

We anticipate that the intervention groups will experience a lower incidence and reduced severity of poststroke epilepsy compared to the control group after 18 months. We aim to establish evidence supporting the potential preventive effects of LEV and PER on poststroke seizures and epilepsy in patients with MCA infarction, as well as to explore the antiepileptogenic potential of both LEV and PER in patients with major ischemic strokes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04858841; https://clinicaltrials.gov/study/NCT04858841.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/49412.

Safety and efficacy of prophylactic levetiracetam for prevention of epileptic seizures in the acute phase of intracerebral haemorrhage (PEACH): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

The incidence of early seizures (occurring within 7 days of stroke onset) after intracerebral haemorrhage reaches 30% when subclinical seizures are diagnosed by continuous EEG. Early seizures might be associated with haematoma expansion and worse neurological outcomes. Current guidelines do not recommend prophylactic antiseizure treatment in this setting. We aimed to assess whether prophylactic levetiracetam would reduce the risk of acute seizures in patients with intracerebral haemorrhage.

METHODS

The double-blind, randomised, placebo-controlled, phase 3 PEACH trial was conducted at three stroke units in France. Patients (aged 18 years or older) who presented with a non-traumatic intracerebral haemorrhage within 24 h after onset were randomly assigned (1:1) to levetiracetam (intravenous 500 mg every 12 h) or matching placebo. Randomisation was done with a web-based system and stratified by centre and National Institutes of Health Stroke Scale (NIHSS) score at baseline. Treatment was continued for 6 weeks. Continuous EEG was started within 24 h after inclusion and recorded over 48 h. The primary endpoint was the occurrence of at least one clinical seizure within 72 h of inclusion or at least one electrographic seizure recorded on continuous EEG, analysed in the modified intention-to-treat population, which comprised all patients who were randomly assigned to treatment and who had a continuous EEG performed. This trial was registered at ClinicalTrials.gov, NCT02631759, and is now closed. Recruitment was prematurely stopped after 48% of the recruitment target was reached due to a low recruitment rate and cessation of funding.

FINDINGS

Between June 1, 2017, and April 14, 2020, 50 patients with mild-to-moderate severity intracerebral haemorrhage were included: 24 were assigned to levetiracetam and 26 to placebo. During the first 72 h, a clinical or electrographic seizure was observed in three (16%) of 19 patients in the levetiracetam group versus ten (43%) of 23 patients in the placebo group (odds ratio 0·16, 95% CI 0·03-0·94, p=0·043). All seizures in the first 72 h were electrographic seizures only. No difference in depression or anxiety reporting was observed between the groups at 1 month or 3 months. Depression was recorded in three (13%) patients who received levetiracetam versus four (15%) patients who received placebo, and anxiety was reported for two (8%) patients versus one (4%) patient. The most common treatment-emergent adverse events in the levetiracetam group versus the placebo group were headache (nine [39%] vs six [24%]), pain (three [13%] vs ten [40%]), and falls (seven [30%] vs four [16%]). The most frequent serious adverse events were neurological deterioration due to the intracerebral haemorrhage (one [4%] vs four [16%]) and severe pneumonia (two [9%] vs two [8%]). No treatment-related death was reported in either group.

INTERPRETATION

Levetiracetam might be effective in preventing acute seizures in intracerebral haemorrhage. Larger studies are needed to determine whether seizure prophylaxis improves functional outcome in patients with intracerebral haemorrhage.

FUNDING

French Ministry of Health.

Differential effects of levetiracetam on hippocampal CA1 synaptic plasticity and molecular changes in the dentate gyrus in epileptic rats

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsies. Pharmacological treatment with anti-seizure drugs (ASDs) remains the mainstay in epilepsy management. Levetiracetam (LEV) is a second-generation ASD with a novel SV2A protein target and is indicated for treating focal epilepsies. While there is considerable literature in acute models, its effect in chronic epilepsy is less clear. Particularly, its effects on neuronal excitability, synaptic plasticity, adult hippocampal neurogenesis, and histological changes in chronic epilepsy have not been evaluated thus far, which formed the basis of the present study. Six weeks post-lithium-pilocarpine-induced status epilepticus (SE), epileptic rats were injected with levetiracetam (54mg/kg b.w. i.p.) once daily for two weeks. Following LEV treatment, Schaffer collateral - CA1 (CA3-CA1) synaptic plasticity and structural changes in hippocampal subregions CA3 and CA1 were evaluated. The number of doublecortin (DCX⁺) and reelin (RLN⁺) positive neurons was estimated. Further, mossy fiber sprouting was evaluated in DG by Timm staining, and splash test was performed to assess the anxiety-like behavior. Chronic epilepsy resulted in decreased basal synaptic transmission and increased paired-pulse facilitation without affecting post-tetanic potentiation and long-term potentiation. Moreover, chronic epilepsy decreased hippocampal subfields volume, adult hippocampal neurogenesis, and increased reelin expression and mossy fiber sprouting with increased anxiety-like behavior. LEV treatment restored basal synaptic transmission and paired-pulse facilitation ratio in CA3-CA1 synapses. LEV also restored the CA1 subfield volume in chronic epilepsy. LEV did not affect epilepsy-induced abnormal adult hippocampal neurogenesis, ectopic migration of newborn granule cells, mossy fiber sprouting in DG, and anxiety-like behavior. Our results indicate that in addition to reducing seizures, LEV has favorable effects on synaptic transmission and structural plasticity in chronic epilepsy. These findings add new dimensions to the use of LEV in chronic epilepsy and paves way for further research into its effects on cognition and affective behavior.

Levetiracetam Mechanisms of Action: From Molecules to Systems

Epilepsy is a chronic disease that affects millions of people worldwide. Antiepileptic drugs (AEDs) are used to control seizures. Even though parts of their mechanisms of action are known, there are still components that need to be studied. Therefore, the search for novel drugs, new molecular targets, and a better understanding of the mechanisms of action of existing drugs is still crucial. Levetiracetam (LEV) is an AED that has been shown to be effective in seizure control and is well-tolerable, with a novel mechanism of action through an interaction with the synaptic vesicle protein 2A (SV2A). Moreover, LEV has other molecular targets that involve calcium homeostasis, the GABAergic system, and AMPA receptors among others, that might be integrated into a single mechanism of action that could explain the antiepileptogenic, anti-inflammatory, neuroprotective, and antioxidant properties of LEV. This puts it as a possible multitarget drug with clinical applications other than for epilepsy. According to the above, the objective of this work was to carry out a comprehensive and integrative review of LEV in relation to its clinical uses, structural properties, therapeutical targets, and different molecular, genetic, and systemic action mechanisms in order to consider LEV as a candidate for drug repurposing.

Risk of Incident Epilepsy After a Middle Cerebral Artery Territory Infarction

Background

Among poststroke morbidities, poststroke epilepsy (PSE) has been identified as a significant clinical issue. Although middle cerebral artery (MCA) infarct is the most common type of stroke among all vascular territories, very few studies specifically focused on the risk factors leading to PSE in patients with MCA infarct.

Methods

A population study in Taiwan has been conducted, linking the National Health Insurance Research Database and Hospital Stroke Registry, from 2001 to 2015 and 2006 to 2010, respectively. Patients were divided into MCA and non-MCA groups, and the diagnosis of incident epilepsy between the groups has been compared. The multivariable Cox proportional hazard model was used to identify the risk factors for developing PSE. The distribution of time to PSE was estimated using the Kaplan–Meier method.

Results

In total, 1,838 patients were recruited, with 774 and 1,064 in the MCA and non-MCA groups, respectively. PSE incidence in the MCA group was 15.5% vs. 6.2% in the non-MCA group, with a hazard ratio of (95% CI) 2.06 (1.33–3.19). Factors significantly associated with PSE included atrial fibrillation, depression, National Institutes of Health Stroke Scale (NIHSS) scores of ≥ 16, and alert on arrival. For patients with MCA infarct, higher NIHSS and Glasgow coma scale scores, the presence of visual field defects and weakness, urination control impairment, and complications during hospitalization were associated with a higher risk for PSE development.

Conclusions

This study established the conditions leading to a higher risk of PSE and identified the important clinical risk factors in patients experiencing MCA infarct. Efforts to manage these risk factors may be important in preventing PSE in patients with MCA infarct.

Levetiracetam promoted rat embryonic neurogenesis via NMDA receptor-mediated mechanism in vitro

AIMS

Levetiracetam (LEV) is a broad-spectrum antiepileptic drug with neuroprotective properties and novel mechanisms of action. Some evidence suggests that LEV may impact adult neurogenesis, but the results are controversial. The present study was aimed to evaluate the effects of LEV on the proliferation and differentiation of rat embryonic neural stem cells (NSCs) and to explore the role of GABAB or NMDA receptors.

MAIN METHODS

NSCs were isolated from rat fetal ganglionic eminence at embryonic day 14.5. The effects of LEV on viability, proliferation, neurosphere formation, and neuronal or astroglial differentiation of NSCs were assessed using resazurin, BrdU incorporation, immunocytochemistry, quantitative real-time PCR, and western blotting. Additionally, we addressed the relationship between treatment with NMDA and GABAB receptor antagonists (MK801 and saclofen, respectively) in combination with LEV on these parameters.

KEY FINDINGS

The data showed that LEV (50 μM) significantly increased the number (p < 0.01) and diameter of neurospheres (p < 0.05), enhanced proliferation (p < 0.01), and promoted neuronal differentiation, as revealed by significantly increased expressions of DCX and NeuN. The expressions of astroglial markers, GFAP and Olig2, were markedly reduced. The addition of MK801 (10 μM) significantly diminished neurospheres growth (p < 0.001), decreased the number of proliferating cells (p < 0.01), and reduced the number of new neurons (p < 0.001) but increased the astroglial cells (p < 0.001) induced by LEV. Co-treatment with saclofen (25 μM) did not significantly affect LEV-induced NSCs proliferation and differentiation.

SIGNIFICANCE

Our findings suggest that LEV may enhance rat embryonic neurogenesis mainly through an NMDA receptor-mediated mechanism.

Internal Carotid Dissection as the Cause of Stroke in Childhood

Internal carotid artery (ICA) dissection is a cause of stroke, but it is often underdiagnosed in children. ICAs' risk factors and pathogenic mechanisms are poorly understood, and the treatment is still empirical. We report the case of a previously healthy 9-year-old girl who presented with involuntary hypertonic closure of the right hand associated with transient difficulty for both fine movements of the right arm and speech. She had a history of minor cervical trauma occurring 20 days prior to our observation without other associated risk factors. Magnetic resonance imaging and magnetic resonance angiography showed ischemic lesions due to the left ICA dissection. Treatment with both acetylsalicylic acid and levetiracetam allowed recanalization of the ICA associated with the resolution of clinical signs. Our clinical case suggests that the ICA dissection must be suspected early whenever a child manifests mild neurologic deficits after a cervical trauma, especially if they are associated with headache and/or cervical pain. Moreover, the management of ICA dissection must be improved.

Neuroprotective and Angiogenesis Effects of Levetiracetam Following Ischemic Stroke in Rats

Objective: The present study explored whether levetiracetam (LEV) could protect against experimental brain ischemia and enhance angiogenesis in rats, and investigated the potential mechanisms in vivo and in vitro.

Methods: The middle cerebral artery was occluded for 60 min to induce middle cerebral artery occlusion (MCAO). The Morris water maze was used to measure cognitive ability. The rotation test was used to assess locomotor function. T2-weighted MRI was used to assess infarct volume. The neuronal cells in the cortex area were stained with cresyl purple. The anti-inflammatory effects of LEV on microglia were observed by immunohistochemistry. Enzyme-linked immunosorbent assays (ELISA) were used to measure the production of pro-inflammatory cytokines. Western blotting was used to detect the levels of heat shock protein 70 (HSP70), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor-1α (HIF-1α) in extracts from the ischemic cortex. Flow cytometry was used to observe the effect of LEV on neuronal cell apoptosis.

Results: LEV treatment significantly increased the density of the surviving neurons in the cerebral cortex and reduced the infarct size (17.8 ± 3.3% vs. 12.9 ± 1.4%, p < 0.01) after MCAO. Concurrently, the time required to reach the platform for LEV-treated rats was shorter than that in the saline group on day 11 after MCAO (p < 0.01). LEV treatment prolonged the rotarod retention time on day 14 after MCAO (84.5 ± 6.7 s vs. 59.1 ± 6.2 s on day 14 compared with the saline-treated groups, p < 0.01). It also suppressed the activation of microglia and inhibited TNF-α and Il-1β in the ischemic brain (135.6 ± 5.2 pg/ml vs. 255.3 ± 12.5 pg/ml, 18.5 ± 1.3 pg/ml vs. 38.9 ± 2.3 pg/ml on day 14 compared with the saline-treated groups, p < 0.01). LEV treatment resulted in a significant increase in HIF-1α, VEGF, and HSP70 levels in extracts from the ischemic cerebral cortex. At the same time, LEV reduced neuronal cell cytotoxicity and apoptosis induced by an ischemic stroke (p < 0.01).

Conclusion: LEV treatment promoted angiogenesis and functional recovery after cerebral ischemia in rats. These effects seem to be mediated through anti-inflammatory and antiapoptotic activities, as well as inducing the expression of HSP70, VEGF, and HIF-1α.

Preclinical Assessment of a New Hybrid Compound C11 Efficacy on Neurogenesis and Cognitive Functions after Pilocarpine Induced Status Epilepticus in Mice

Status epilepticus (SE) is a frequent medical emergency that can lead to a variety of neurological disorders, including cognitive impairment and abnormal neurogenesis. The aim of the presented study was the in vitro evaluation of potential neuroprotective properties of a new pyrrolidine-2,5-dione derivatives compound C11, as well as the in vivo assessment of the impact on the neurogenesis and cognitive functions of C11 and levetiracetam (LEV) after pilocarpine (PILO)-induced SE in mice. The in vitro results indicated a protective effect of C11 (500, 1000, and 2500 ng/mL) on astrocytes under trophic stress conditions in the MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) test. The results obtained from the in vivo studies, where mice 72 h after PILO SE were treated with C11 (20 mg/kg) and LEV (10 mg/kg), indicated markedly beneficial effects of C11 on the improvement of the neurogenesis compared to the PILO control and PILO LEV mice. Moreover, this beneficial effect was reflected in the Morris Water Maze test evaluating the cognitive functions in mice. The in vitro confirmed protective effect of C11 on astrocytes, as well as the in vivo demonstrated beneficial impact on neurogenesis and cognitive functions, strongly indicate the need for further advanced molecular research on this compound to determine the exact neuroprotective mechanism of action of C11.

Levetiracetam and N-Cadherin Antibody Alleviate Brain Pathology Without Reducing Early Epilepsy Development After Focal Non-convulsive Status Epilepticus in Rats

Focal non-convulsive status epilepticus (fNCSE) is a neurological condition characterized by a prolonged seizure that may lead to the development of epilepsy. Emerging experimental evidence implicates neuronal death, microglial activation and alterations in the excitatory and inhibitory synaptic balance as key features in the pathophysiology following fNCSE. We have previously reported alterations in the excitatory adhesion molecule N-cadherin in rats with fNCSE originating from the hippocampus that subsequently also develop spontaneous seizures. In this study, fNCSE rats were treated intraperitoneally with the conventional anti-epileptic drug levetiracetam in combination with intraparenchymal infusion of N-cadherin antibodies (Ab) for 4 weeks post-fNCSE. The N-cadherin Ab was infused into the fornix and immunohistochemically N-cadherin Ab-stained neurons were detected within the dorsal hippocampal structures as well as in superjacent somatosensory cortex. Continuous levetiracetam treatment for 4 weeks post-fNCSE reduced microglia activation, including cell numbers and morphological changes, partly decreased neuronal cell loss, and excitatory post-synaptic scaffold protein PSD-95 expression in selective hippocampal structures. The additional treatment with N-cadherin Ab did not reverse neuronal loss, but moderately reduced microglial activation, and further reduced PSD-95 levels in the dentate hilus of the hippocampus. Despite the effects on brain pathology within the epileptic focus, neither monotherapy with systemic levetiracetam nor levetiracetam in combination with local N-cadherin Ab administration, reduced the amount of focal or focal evolving into bilateral convulsive seizures, seizure duration, or interictal epileptiform activity during 1 month of continuous electroenephalogram recordings within the hippocampus after fNCSE. Behavioral tests for spatial memory, anxiety, social interaction and anhedonia did not detect gross behavioral differences between fNCSE rats with or without treatment. The results reveal the refractory features of the present rodent model of temporal lobe epilepsy following fNCSE, which supports its clinical value for further therapeutic studies. We identify the persistent development of epilepsy following fNCSE, in spite of partly reduced brain pathology within the epileptic focus.

Seizures and epilepsy after intracerebral hemorrhage: an update

Seizures are common after intracerebral hemorrhage, occurring in 6-15% of the patients, mostly in the first 72 h. Their incidence reaches 30% when subclinical or non-convulsive seizures are diagnosed by continuous electroencephalogram. Several risk factors for seizures have been described including cortical location of intracerebral hemorrhage, presence of intraventricular hemorrhage, total hemorrhage volume, and history of alcohol abuse. Seizures after intracerebral hemorrhage may theoretically be harmful as they can lead to sudden blood pressure fluctuations, increased intracranial pressure, and neuronal injury due to increased metabolic demand. Some recent studies suggest that acute symptomatic seizures (occurring within 7 days of stroke) are associated with worse functional outcome and increased risk of death despite accounting for other known prognostic factors such as age and baseline hemorrhage volume. However, the impact of seizures on prognosis is still debated and it remains unclear if treating or preventing seizures might lead to improved clinical outcome. Thus, the currently available scientific evidence does not support the routine use of antiseizure medication as primary prevention among patients with intracerebral hemorrhage. Only prospective adequately powered randomized-controlled trials will be able to answer whether seizure prophylaxis in the acute or longer term settings is beneficial or not in patients with intracerebral hemorrhage.

Age-dependent anticonvulsant actions of perampanel and brivaracetam in the methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) model of seizures in developing rats

BACKGROUND

The antiseizure drugs commonly used as first- and second-line treatments for neonatal seizures display poor efficacy. Thus, drug mechanisms of action that differ from these typical agents might provide better seizure control. Perampanel, an AMPA-receptor antagonist, and brivaracetam, a SV2A ligand, might fill that role.

METHODS

We utilized methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) to evoke seizures in rats to assess the efficacy of perampanel and brivaracetam treatment in clinically relevant doses.

RESULTS

In postnatal day (P)10 rats, neither perampanel nor brivaracetam suppressed seizure activity. By contrast, in P21 rats, both drugs decreased the severity of seizures. This effect was evident at the 20 and 40 mg/kg doses of brivaracetam and at the 0.9 and 2.7 mg/kg doses of perampanel.

CONCLUSIONS

These data indicate that while the efficacy of these drugs may be limited for neonatal seizures, their efficacy increases over early postnatal development.

Diagnosis and long-term management of post-traumatic seizures in a white-crowned pionus (Pionus senilis)

CASE DESCRIPTION

A 13-year-old female white-crowned pionus (Pionus senilis) was examined because of seizures 22 months after it was treated for a traumatic brain injury (TBI) characterized by vision loss, hemiparesis, nystagmus, circling, and head tilt.

CLINICAL FINDINGS

Bloodwork performed during the initial seizure workup revealed hypercalcemia and hypercholesterolemia, which were attributed to vitellogenesis given the bird's previous egg-laying history and recent onset of reproductive behavior. Magnetic resonance imaging of the brain revealed diffuse right pallium atrophy with multifocal hydrocephalus ex vacuo, which were believed to be the result of the previous TBI. Findings were most consistent with post-traumatic seizures (PTS).

TREATMENT AND OUTCOME

Levetiracetam (100 mg/kg [45 mg/lb], PO, q 12 h) was initiated for PTS management. A 4.7-mg deslorelin implant was injected SC to suppress reproductive behavior. The bird was reexamined for presumed status epilepticus 5 times over 22 months. Seizure episodes coincided with onset of reproductive behavior. The levetiracetam dosage was increased (150 mg/kg [68 mg/lb], PO, q 8 h), and zonisamide (20 mg/kg [9.1 mg/lb], PO, q 12 h) was added to the treatment regimen. Additional deslorelin implants were administered every 2 to 6 months to suppress reproductive behavior. The owner was trained to administer midazolam intranasally or IM as needed at home. The treatment regimen helped control but did not eliminate seizure activity. The bird was euthanized 22 months after PTS diagnosis for reasons unrelated to the TBI or PTS.

CLINICAL RELEVANCE

Long-term management of PTS in a pionus was achieved with levetiracetam and zonisamide administration.

Levetiracetam Improves Upper Limb Spasticity in a Patient With Unresponsive Wakefulness Syndrome: A Case Report

Severe spasticity is a frequent and disabling complication in patients presenting disorders of consciousness (DOC) that hinders their rehabilitative process, and is strongly correlated with pain reducing patients' quality of life. In these patients, abnormal postures may occur as an expression of severe brain damage. Here we present the case of a 52-year-old man in decorticate rigidity following a hypoxic-ischemic encephalopathy due to myocardial infarction who showed improvement of spasticity of upper limbs following intake of levetiracetam combined with the conventional neurorehabilitation program.

Nanotherapeutic modulation of excitotoxicity and oxidative stress in acute brain injury

Excitotoxicity is a primary pathological process that occurs during stroke, traumatic brain injury (TBI), and global brain ischemia such as perinatal asphyxia. Excitotoxicity is triggered by an overabundance of excitatory neurotransmitters within the synapse, causing a detrimental cascade of excessive sodium and calcium influx, generation of reactive oxygen species, mitochondrial damage, and ultimately cell death. There are multiple potential points of intervention to combat excitotoxicity and downstream oxidative stress, yet there are currently no therapeutics clinically approved for this specific purpose. For a therapeutic to be effective against excitotoxicity, the therapeutic must accumulate at the disease site at the appropriate concentration at the right time. Nanotechnology can provide benefits for therapeutic delivery, including overcoming physiological obstacles such as the blood-brain barrier, protect cargo from degradation, and provide controlled release of a drug. This review evaluates the use of nano-based therapeutics to combat excitotoxicity in stroke, TBI, and hypoxia-ischemia with an emphasis on mitigating oxidative stress, and consideration of the path forward toward clinical translation.

Evaluation of the impact of compound C11 a new anticonvulsant candidate on cognitive functions and hippocampal neurogenesis in mouse brain

Searching for the new and effective anticonvulsants in our previous study we developed a new hybrid compound C-11 derived from 2-(2,5-dioxopyrrolidin-1-yl) propanamide. C11 revealed high efficacy in acute animal seizure models such as the maximal electroshock model (MES), the pentylenetetrazole model (PTZ) and the 6 Hz (6 Hz, 32 mA) seizure model, as well as in the kindling model of epilepsy induced by repeated injection of PTZ in mice. In the aim of further in vivo C11 characterization, in the current studies we evaluated its influence on cognitive functions, neurodegeneration and neurogenesis process in mice after chronical treatment. All experiments were performed on 6 weeks old male C57/BL mice. The following drugs were used: C11, levetiracetam (LEV), ethosuximide (ETS) and lacosamide (LCM). We analyzed proliferation, migration and differentiation of newborn cells as well as neurodegenerative changes in a mouse brain after long-term treatment with aforementioned AEDs. Additionally, we evaluated changes in learning and memory functions in response to chronic C11, LEV, LCM and ETS treatment. C11 as well as LEV and ETS did not disturb the proliferation of newborn cells compared to the control mice, whereas LCM treatment significantly decreased it. Chronic AEDs therapy did not induce significant neurodegenerative changes. Behavioral studies with using Morris Water Maze test did not indicate any disturbances in the spatial learning and memory after C11 as well as LEV and ETS treatment in comparison to the control group except LCM mice where significant dysfunctions in time, distance and direct swim to the platform were observed. Interestingly, results obtained from in vivo MRI spectroscopy showed a statistically significant increase of one of the neurometabolites- N-acetyloaspartate (NAA) for LCM and LEV mice. A new hybrid compound C11 in contrast to LCM has no negative impact on the process of neurogenesis and neurodegeneration in the mouse hippocampus. Furthermore, chronic treatment with C11 turned out to have no negative impact on cognitive functions of treated mice, which, is certainly of great importance for further more advanced preclinical and especially clinical trials.

Proof-of-concept that network pharmacology is effective to modify development of acquired temporal lobe epilepsy

Epilepsy is a complex network phenomenon that, as yet, cannot be prevented or cured. We recently proposed network-based approaches to prevent epileptogenesis. For proof of concept we combined two drugs (levetiracetam and topiramate) for which in silico analysis of drug-protein interaction networks indicated a synergistic effect on a large functional network of epilepsy-relevant proteins. Using the intrahippocampal kainate mouse model of temporal lobe epilepsy, the drug combination was administered during the latent period before onset of spontaneous recurrent seizures (SRS). When SRS were periodically recorded by video-EEG monitoring after termination of treatment, a significant decrease in incidence and frequency of SRS was determined, indicating antiepileptogenic efficacy. Such efficacy was not observed following single drug treatment. Furthermore, a combination of levetiracetam and phenobarbital, for which in silico analysis of drug-protein interaction networks did not indicate any significant drug-drug interaction, was not effective to modify development of epilepsy. Surprisingly, the promising antiepileptogenic effect of the levetiracetam/topiramate combination was obtained in the absence of any significant neuroprotective or anti-inflammatory effects as indicated by multimodal brain imaging and histopathology. High throughput RNA-sequencing (RNA-seq) of the ipsilateral hippocampus of mice treated with the levetiracetam/topiramate combination showed that several genes that have been linked previously to epileptogenesis, were significantly differentially expressed, providing interesting entry points for future mechanistic studies. Overall, we have discovered a novel combination treatment with promise for prevention of epilepsy.

Incidence, Implications, and Management of Seizures Following Ischemic and Hemorrhagic Stroke

PURPOSE OF REVIEW

In this review, we summarize the recent literature regarding the incidence and treatment of seizures arising after ischemic and hemorrhagic strokes. Additionally, we identify open questions in guidelines and standard clinical care to aid future studies aiming to improve management of seizures in post-stroke patients.

RECENT FINDINGS

Studies demonstrate an increasing prevalence of seizures following strokes, probably a consequence of advances in post-stroke management and expanding use of continuous EEG monitoring. Post-stroke seizures are associated with longer hospitalization and increased mortality; therefore, prevention and timely treatment of seizures are important. The standard of care is to treat recurrent seizures with anti-epileptic drugs (AEDs) regardless of the etiology. However, there are no established guidelines currently for prophylactic use of AEDs following a stroke. The prevalence of post-stroke seizures is increasing. Further studies are needed to determine the risk factors for recurrent seizures and epilepsy after strokes and optimal treatment strategies.

Synaptic vesicle protein 2A as a potential biomarker in synaptopathies

Measuring synaptic density in vivo using positron emission tomography (PET) imaging-based biomarkers targeting the synaptic vesicle protein 2A (SV2A) has received much attention recently due to its potential research and clinical applications in synaptopathies, including neurodegenerative and psychiatric diseases. Fluid-based biomarkers in proteinopathies have previously been suggested to provide information on pathology and disease status that is complementary to PET-based measures, and the same can be hypothesized with respect to SV2A. This review provides an overview of the current state of SV2A PET imaging as a biomarker of synaptic density, the potential role of fluid-based biomarkers for SV2A, and related future perspectives.

[Cognitive and paroxysmal disorders in the long-term period of traumatic brain injury in children and adolescents]

Traumatic brain injury (TBI) clinical course and outcomes in children have peculiarities as the damage impacts brain, which growth and maturation are continuing. Thus, TBI interferes into normal processes of neuroontogenesis leading to negative consequences on the cognitive functions development, school education, social skills acquisition. Cognitive and behavioral disorders in children and adolescents in the long-term period of TBI become more prominent in co-occurrence with paroxysmal disorders, including posttraumatic headaches, posttraumatic epilepsy and subclinical epileptiform activity on the EEG. Therapeutic and rehabilitation procedures in in the long-term period of TBI in children and adolescents should be conducted not only during the first 12 months after injury, when they are expected to be the most efficient, but also later on taking into consideration continuing processes of the CNS morphological and functional maturation along with the high neuroplasticity of the developing brain.

Levetiracetam combined with ACEA, highly selective cannabinoid CB1 receptor agonist changes neurogenesis in mouse brain

The aim of the study was to evaluate the impact of second generation antiepileptic drug levetiracetam (LEV) with arachidonyl-2'-chloroethylamide (ACEA) on proliferating neural precursor cells in mouse brain. Additionally, we established the relationship between treatment with ACEA in combination with LEV and hippocampal neurogenesis in mouse brain. All experiments were performed on male CB57/BL mice injected i.p. with LEV (10 mg/kg), ACEA (10 mg/kg) and PMSF (30 mg/kg) for 10 days. Experiments were provided in two stages: stage 1- an acute response of proliferating neural precursor cells to ACEA and LEV administration (Ki-67 staining), stage 2 - a long term response to ACEA and LEV administration (BrDU, NeuN, GFAP staining). Results indicate that ACEA + PMSF and ACEA + PMSF + LEV significantly increased the total number of Ki-67 positive cells comparing to the control group. PMSF and LEV administered alone and in combination had no significant impact on cell proliferation compared to the control group. Results from neurogenesis study indicated that ACEA + PMSF administered alone and in combination with LEV increased the total number of BrDU cells compared to the control group, although LEV on its own decreased the number of BrDU cells. Moreover, the combination of ACEA + PMSF + LEV significantly increased the total number of newborn neurons compared to the control group. In turn, LEV significantly decreased the process of neurogenesis. Astrocytes were considerably reduced in all treated groups as compare to the control mice. These data provide substantial evidence that LEV administered chronically decreases the proliferation and differentiation of newly born cells while combination of LEV + ACEA significantly increases the level of newborn neurons in the dentate subgranular zone.

Stroke-related epilepsy

Stroke is the cause of about 10% of all epilepsy and 55% of newly diagnosed seizures among the elderly. Although recent advances in acute stroke therapy have improved longevity, there has been a consequent rise in the prevalence of stroke-related epilepsy (STRE). Many clinical studies make a distinction between early (within 7 days of onset of stroke) and late (beyond 7 days of onset of stroke) seizures based on presumed pathophysiological differences. Although early seizures are thought to be the consequence of local metabolic disturbances without altered neuronal networks, late seizures are thought to occur when the brain has acquired a predisposition for seizures. Overall, STRE has a good prognosis, being well controlled by antiepileptic drugs. However, up to 25% of cases become drug resistant. STRE can also result in increased morbidity, longer hospitalization, greater disability at discharge and greater resource utilization. Additional controlled trials are needed to explore the primary and secondary prevention of STRE as well as to provide high-quality evidence on efficacy and tolerability of antiepileptic drugs to guide treatment of STRE. Robust pre-clinical and clinical prediction models of STRE are also needed to develop treatments to prevent the transformation of infarcted tissue into an epileptic focus.

Effects of Antiepileptic Drugs on Spontaneous Recurrent Seizures in a Novel Model of Extended Hippocampal Kindling in Mice

Epilepsy is a common neurological disorder characterized by naturally-occurring spontaneous recurrent seizures and comorbidities. Kindling has long been used to model epileptogenic mechanisms and to assess antiepileptic drugs. In particular, extended kindling can induce spontaneous recurrent seizures without gross brain lesions, as seen clinically. To date, the development of spontaneous recurrent seizures following extended kindling, and the effect of the antiepileptic drugs on these seizures are not well understood. In the present study we aim to develop a mouse model of extended hippocampal kindling for the first time. Once established, we plan to evaluate the effect of three different antiepileptic drugs on the development of the extended-hippocampal-kindled-induced spontaneous recurrent seizures. Male C57 black mice were used for chronic hippocampal stimulations or handling manipulations (twice daily for up to 70 days). Subsequently, animals underwent continuous video/EEG monitoring for seizure detection. Spontaneous recurrent seizures were consistently observed in extended kindled mice but no seizures were detected in the control animals. The aforementioned seizures were generalized events characterized by hippocampal ictal discharges and concurrent motor seizures. Incidence and severity of the seizures was relatively stable while monitored over a few months after termination of the hippocampal stimulation. Three antiepileptic drugs with distinct action mechanisms were tested: phenytoin, lorazepam and levetiracetam. They were applied via intra-peritoneal injections at anticonvulsive doses and their effects on the spontaneous recurrent seizures were analyzed 10-12 h post-injection. Phenytoin (25 mg/kg) and levetiracetam (400 mg/kg) abolished the spontaneous recurrent seizures. Lorazepam (1.5 mg/kg) decreased motor seizure severity but did not reduce the incidence and duration of corresponding hippocampal discharges, implicating its inhibitory effects on seizure spread. No gross brain lesions were observed in a set of extended hippocampal kindled mice submitted to histological evaluation. All these data suggests that our model could be considered as a novel mouse model of extended hippocampal kindling. Some limitations remain to be considered.

Antinociceptive and pronociceptive effect of levetiracetam in tonic pain model

BACKGROUND

Levetiracetam (LEV) is a novel anticonvulsant with proven antinociceptive properties. However, the antinociceptive and pronociceptive effect of this drug has not yet been fully elucidated in a tonic pain model.

METHODS

Thirty-six male rats (Wistar) were randomized into six groups and underwent the formalin test as follows: rats in the control group were administered 50μL of 1% formalin in the paw; sham-group rats were administered 50μL of saline in the paw to mimick the application of formalin; the four experimental groups were administered LEV intragastrically (ig) (50, 100, 200 and 300mg/kg), and 40min later 50μL of 1% formalin was injected in the paw.

RESULTS

LEV exhibited antinociceptive effect in the 300mg/kg LEV group (p<0.05) and a pronociceptive effect in the 100mg/kg LEV group (p<0.05) and in the 50mg/kg LEV group (p<0.001).

CONCLUSIONS

The antinociceptive and pronociceptive effect of LEV in a tonic pain model is dose-dependent.

The Progress of Epilepsy after Stroke

BACKGROUND

Epilepsy is the second most common disease caused by multiple factors and characterized by an excessive discharge of certain neurons in the nervous system. Cerebrovascular disease, including stroke, is viewed as the most common cause of epilepsy in the elderly population, accounting for 30%-50% of the newly diagnosed cases of epilepsy cases in this age group.

METHODS

Data were collected from Web of Science, Medline, Pubmed, Scopus, through searching of these keywords: "Stroke" and "epilepsy".

RESULTS

Depending on the underlying cerebrovascular disease, 3%-30% of patients after stroke may develop post-stroke epilepsy (PSE), which has a negative effect on stroke prognosis and the quality of life.

CONCLUSION

In this review, we summarized new aspects emerging from research into PSE, including definition, epidemiology, risk factors, mechanism, accessory examination and treatment strategies for post-stroke epilepsy, which will enrich our knowledge of this disorder.

Population pharmacokinetics of levetiracetam in neonates with seizures

WHAT IS KNOWN AND OBJECTIVE

This study developed a population pharmacokinetic (PK) model of levetiracetam (LEV) for treating neonatal seizures (NS) and determined the influence of clinically relevant covariates to explain the interindividual variability and residual error.

METHODS

Twenty newborns admitted to the Neonatal Intensive Care Unit at the Hospital Central "Dr. Ignacio Morones Prieto" were included. LEV doses were administered by intermittent infusion. Blood samples were drawn 3 times post-infusion. Levetiracetam was quantified by a chromatographic technique. NONMEM software was used to determine the population PK model of LEV in neonates and the influence of clinical covariates on drug disposition.

RESULTS AND DISCUSSION

The LEV PK in neonates is described by a one-compartment open model with first-order elimination. The influence of creatinine clearance (CRCL) and body weight (BW) on clearance (CL[L/h] = 0.47*CRCL), as well as the volume of the distribution (Vd[L] = 0.65*BW) of LEV, were confirmed, considering interindividual variabilities of 36% and 22%, respectively, and a residual error of 13%.

WHAT IS NEW AND CONCLUSION

Based on the PK of LEV in neonates and the influence of the final PK model, a priori dosing guidelines are proposed considering CRCL, BW and LEV plasma concentrations between 6 and 20 mg/L for NS treatment.

A Systematic Appraisal of Neurosurgical Seizure Prophylaxis: Guidance for Critical Care Management

Clinical decisions are often made in the presence of some uncertainty. Health care should be based on a combination of scientific evidence, clinical experience, economics, patient value judgments, and preferences. Seizures are not uncommon following brain injury, surgical trauma, hemorrhage, altered brain metabolism, hypoxia, or ischemic events. The impact of seizures in the immediate aftermath of injury may be a prolonged intensive care stay or compounding of the primary injury. The aim of brain injury management is to limit the consequences of the secondary damage. The original intention of seizure prophylaxis was to limit the incidence of early-onset seizures. However, clinical trials have been equivocal on this point, and there is concern about the adverse effects of antiepileptic drug therapy. This review of the literature raises concerns regarding the arbitrary division of seizures into early onset (7 d) and late onset (8 d and beyond). In many cases it would appear that seizures present within 24 hours of the injury or after 7 days, which would be outside of the scope of current seizure prophylaxis guidance. There also does not appear to be a pathophysiological reason to divide brain injury-related seizures into these timeframes. Therefore, a solution to the conundrum is to reevaluate current practice. Prophylaxis could be offered to those receiving intensive care for the primary brain injury, where the impact of seizure would be detrimental to the management of the brain injury, or other clinical judgments where prophylaxis is prudent. Neurosurgical seizure management can then focus attention on which agent has the best adverse effect profile and the duration of therapy. The evidence seems to support levetiracetam as the most appropriate agent. Although previous reviews have identified an increase cost associated with the use of levetiracetam, current cost comparisons with phenytoin demonstrate a marginal price differential. The aim of this review is to assimilate the applicable literature regarding seizure prophylaxis. The final guidance is a forum upon which further clinical research could evaluate a new seizure prophylaxis paradigm.

Post-stroke epilepsy

Post-stroke epilepsy (PSE) is a common complication after stroke, yet treatment options remain limited. While many physicians prescribe antiepileptic drugs (AED) for secondary prevention of PSE, it is unclear which treatments are most effective in the prevention of recurrence of symptoms, or whether such therapy is needed for primary prevention. This review discusses the current understanding of epidemiology, diagnoses, mechanisms, risk factors, and treatments of PSE.

Levetiracetam Treatment in Traumatic Brain Injury: Operation Brain Trauma Therapy

Levetiracetam (LEV) is an antiepileptic agent targeting novel pathways. Coupled with a favorable safety profile and increasing empirical clinical use, it was the fifth drug tested by Operation Brain Trauma Therapy (OBTT). We assessed the efficacy of a single 15 min post-injury intravenous (IV) dose (54 or 170 mg/kg) on behavioral, histopathological, and biomarker outcomes after parasagittal fluid percussion brain injury (FPI), controlled cortical impact (CCI), and penetrating ballistic-like brain injury (PBBI) in rats. In FPI, there was no benefit on motor function, but on Morris water maze (MWM), both doses improved latencies and path lengths versus vehicle (p < 0.05). On probe trial, the vehicle group was impaired versus sham, but both LEV treated groups did not differ versus sham, and the 54 mg/kg group was improved versus vehicle (p < 0.05). No histological benefit was seen. In CCI, there was a benefit on beam balance at 170 mg/kg (p < 0.05 vs. vehicle). On MWM, the 54 mg/kg dose was improved and not different from sham. Probe trial did not differ between groups for either dose. There was a reduction in hemispheric tissue loss (p < 0.05 vs. vehicle) with 170 mg/kg. In PBBI, there was no motor, cognitive, or histological benefit from either dose. Regarding biomarkers, in CCI, 24 h glial fibrillary acidic protein (GFAP) blood levels were lower in the 170 mg/kg group versus vehicle (p < 0.05). In PBBI, GFAP blood levels were increased in vehicle and 170 mg/kg groups versus sham (p < 0.05) but not in the 54 mg/kg group. No treatment effects were seen for ubiquitin C-terminal hydrolase-L1 across models. Early single IV LEV produced multiple benefits in CCI and FPI and reduced GFAP levels in PBBI. LEV achieved 10 points at each dose, is the most promising drug tested thus far by OBTT, and the only drug to improve cognitive outcome in any model. LEV has been advanced to testing in the micropig model in OBTT.

The safety and efficacy of levetiracetam versus phenytoin for seizure prophylaxis after traumatic brain injury: A systematic review and meta-analysis

BACKGROUND

The standard for early traumatic brain injury (TBI) seizure prophylaxis is phenytoin (PHT). Levetiracetam (LEV) has been proposed as an alternative to PHT. The aim of this study was to evaluate the safety and efficacy of LEV on TBI seizure when compared with PHT.

METHODS

A search was carried out based on the databases from Pubmed, Embase and the Cochrane database up to May 2015. The relative risk (RR) and the relevant 95% confidence intervals (CI) were determined.

RESULTS

Eight observational studies and one randomized controlled trial involving 2035 cases were included. The results indicated that no significant differences in terms of overall seizure (RR = 0.90; 95% CI = 0.51-1.53; p = 0.68), early seizure (RR = 1.06; 95% CI = 0.37-3.07; p = 0.92) and late seizure (RR = 1.10; 95% CI = 0.43-2.79; p = 0.85) occurrence. However, LEV was associated with a lower adverse drug reaction rate (RR = 0.43; 95% CI = 0.23-0.81; p = 0.01). Moreover, there were no significant differences in terms of mortality, length of ICU or hospital stay between groups.

CONCLUSIONS

The meta-analysis suggests that LEV appears to have a similar efficacy to PHT on TBI. A better safety profile of LEV is supported by this analysis.

Effects of Different Doses of Levetiracetam on Aquaporin 4 Expression in Rats with Brain Edema Following Fluid Percussion Injury

Background

This study was designed to investigate the effects of different doses of levetiracetam on aquaporin 4 (AQP4) expression in rats after fluid percussion injury.

Material/Methods

Sprague-Dawley rats were randomly divided into 4 groups: sham operation group, traumatic brain injury group, low-dose levetiracetam group, and high-dose levetiracetam group. Brain edema models were established by fluid percussion injury, and intervened by the administration of levetiracetam. Samples from the 4 groups were collected at 2, 6, 12, and 24 h, and at 3 and 7 days after injury. Histological observation was performed using hematoxylin-eosin staining and immunohistochemical staining. AQP4 and AQP4 mRNA expression was detected using Western blot assay and RT-PCR. Brain water content was measured by the dry-wet method.

Results

Compared with the traumatic brain injury group, brain water content, AQP4 expression, and AQP4 mRNA expression were lower in the levetiracetam groups at each time point and the differences were statistically significant (P<0.05). The intervention effects of high-dose levetiracetam were more apparent.

Conclusions

Levetiracetam can lessen brain edema from fluid percussion injury by down-regulating AQP4 and AQP4 mRNA expression. There is a dose-effect relationship in the preventive effect of levetiracetam within a certain extent.

Neuroprotection as a Potential Therapeutic Perspective in Neurodegenerative Diseases: Focus on Antiepileptic Drugs

Neuroprotection is conceived as one of the potential tool to prevent or slow neuronal death and hence a therapeutic hope to treat neurodegenerative diseases, like Parkinson's and Alzheimer's diseases. Increase of oxidative stress, mitochondrial dysfunction, excitotoxicity, inflammatory changes, iron accumulation, and protein aggregation have been identified as main causes of neuronal death and adopted as targets to test experimentally the putative neuroprotective effects of various classes of drugs. Among these agents, antiepileptic drugs (AEDs), both the old and the newer generations, have shown to exert protective effects in different experimental models. Their mechanism of action is mediated mainly by modulating the activity of sodium, calcium and potassium channels as well as the glutamatergic and GABAergic (gamma-aminobutyric acid) synapses. Neurological pathologies in which a neuroprotective action of AEDs has been demonstrated in specific experimental models include: cerebral ischemia, Parkinson's disease, and Alzheimer's disease. Although the whole of experimental data indicating that neuroprotection can be achieved is remarkable and encouraging, no firm data have been produced in humans so far and, at the present time, neuroprotection still remains a challenge for the future.

Early-Onset Convulsive Seizures Induced by Brain Hypoxia-Ischemia in Aging Mice: Effects of Anticonvulsive Treatments

Aging is associated with an increased risk of seizures/epilepsy. Stroke (ischemic or hemorrhagic) and cardiac arrest related brain injury are two major causative factors for seizure development in this patient population. With either etiology, seizures are a poor prognostic factor. In spite of this, the underlying pathophysiology of seizure development is not well understood. In addition, a standardized treatment regimen with anticonvulsants and outcome assessments following treatment has yet to be established for these post-ischemic seizures. Previous studies have modeled post-ischemic seizures in adult rodents, but similar studies in aging/aged animals, a group that mirrors a higher risk elderly population, remain sparse. Our study therefore aimed to investigate early-onset seizures in aging animals using a hypoxia-ischemia (HI) model. Male C57 black mice 18-20-month-old underwent a unilateral occlusion of the common carotid artery followed by a systemic hypoxic episode (8% O2 for 30 min). Early-onset seizures were detected using combined behavioral and electroencephalographic (EEG) monitoring. Brain injury was assessed histologically at different times post HI. Convulsive seizures were observed in 65% of aging mice post-HI but not in control aging mice following either sham surgery or hypoxia alone. These seizures typically occurred within hours of HI and behaviorally consisted of jumping, fast running, barrel-rolling, and/or falling (loss of the righting reflex) with limb spasms. No evident discharges during any convulsive seizures were seen on cortical-hippocampal EEG recordings. Seizure development was closely associated with acute mortality and severe brain injury on brain histological analysis. Intra-peritoneal injections of lorazepam and fosphenytoin suppressed seizures and improved survival but only when applied prior to seizure onset and not after. These findings together suggest that seizures are a major contributing factor to acute mortality in aging mice following severe brain ischemia and that early anticonvulsive treatment may prevent seizure genesis and improve overall outcomes.

Metabolic Encephalopathy and Lipid Storage Myopathy Associated with a Presumptive Mitochondrial Fatty Acid Oxidation Defect in a Dog

A 1-year-old spayed female Shih Tzu presented for episodic abnormalities of posture and mentation. Neurological examination was consistent with a bilaterally symmetric multifocal encephalopathy. The dog had a waxing-and-waning hyperlactemia and hypoglycemia. Magnetic resonance imaging revealed bilaterally symmetric cavitated lesions of the caudate nuclei with less severe abnormalities in the cerebellar nuclei. Empirical therapy was unsuccessful, and the patient was euthanized. Post-mortem histopathology revealed bilaterally symmetric necrotic lesions of the caudate and cerebellar nuclei and multi-organ lipid accumulation, including a lipid storage myopathy. Malonic aciduria and ketonuria were found on urinary organic acid screen. Plasma acylcarnitine analysis suggested a fatty acid oxidation defect. Fatty acid oxidation disorders are inborn errors of metabolism documented in humans, but poorly described in dogs. Although neurological signs have been described in humans with this group of diseases, descriptions of advanced imaging, and histopathology are severely lacking. This report suggests that abnormalities of fatty acid metabolism may cause severe, bilateral gray matter necrosis, and lipid accumulation in multiple organs including the skeletal muscles, liver, and kidneys. Veterinarians should be aware that fatty acid oxidation disorders, although potentially fatal, may be treatable. A timely definitive diagnosis is essential in guiding therapy.

Levetiracetam Prevents Perforin Mediated Neuronal Injury Induced by Acute Cerebral Ischemia Reperfusion

The purpose of this study is to explore the neuroprotection mechanism of levetiracetam (LEV) with acute focal cerebral ischemia-reperfusion (I/P) mouse. The cerebral artery I/P animal model was prepared with a middle artery cerebral occlusion method. For drug intervention, mice were intraperitoneally injected with LEV with a dose of either 15 or 150 mg/kg. Neuronal injury was evaluated by measuring the infarct area, apoptosis ratio, and observation of blood-brain barrier ultrastructure with transmission electron microscope. CD8(+) antibody and perforin antibody were used to make cross-reference screen through flow cytometry to determine a perforin-positive rate in CD8(+) T lymphocytes (PFN + %). Injection of LEV can reduce infarct area, apoptosis ratio, and blood-brain barrier damage 24 h later after acute I/P in WT mice. In vitro, perforin can lower hippocampal neuron viability. In vivo, removing perforin can relieve neuronal injury. High dose injection of LEV (150 mg/kg) can inhibit perforin secreting from CD8(+)T lymphocytes. In addition, LEV can still protect neurons with perforin knockout mice. Therefore, our results suggested that LEV may contribute to neuron protection after cerebral ischemia reperfusion. The possible mechanism may be related with perforin release. However, we cannot roll out other mechanisms.

Phenytoin is an estrogen receptor α-selective modulator that interacts with helix 12

RATIONALE

Phenytoin (Dilantin(®); DPH) is used to treat epilepsy but causes estrogen agonist-antagonist-like side effects. We investigated the interaction of phenytoin with estrogen receptors (ERs) α and β by computational molecular docking, ER competition binding, transcriptional assays, and biological actions, comparing outcomes with estradiol (E2), estrone (E1), and tamoxifen (TMX).

EXPERIMENTAL

(1) The DPH docking to 3-dimensional crystal structures of the ERα ligand-binding domain (LBD) showed a high degree of structural complementarity (-57.15 calculated energy units, approximating kcal/mol) with the ligand-binding pocket, including a contact at leucine (L540) in helix 12. Estrogen receptor β showed slightly less favorable interactions (-54.27 kcal/mol), without contacting L450. Estradiol, E1, and TMX contact points with ERα and ERβ do not include L450. (2) Cellular actions: Incubation of cells transfected with ERα or ERβ and a luciferase promoter phenytoin was several orders weaker than E2 as an agonist through ERα and had no effect through ERβ. However, phenytoin at clinical concentrations (10(-11) to 10(-6) mol/L) powerfully antagonized action of E2 on ERα-expressing cells. Similarly, phenytoin at clinically effective concentrations marginally induced alkaline phosphatase by ERα- and ERβ-expressing endometrial cancer cells but at doses well below clinical effectiveness blocked E2-induced alkaline phosphatase. (3) ER competition: In Scatchard plots comparing phenytoin with 17β-estradiol against endometrial cancer cell cytosol E2-alone more effectively displaced labeled E2 than phenytoin, but phenytoin was approximately equimolar effective to E2 in inhibiting E2's displacement of the radiolabel, further confirming that phenytoin is a strong E2 antagonist.

CONCLUSIONS

At clinically effective concentrations, phenytoin is a strong ERα cell antagonist but a many-fold weaker agonist. Although it interacts with ERβ LBD residues, phenytoin has no effects on ERβ-only expressing cells. Docking studies indicate phenytoin interacts with the ERα LBD at the hinge of helix 12 and could thereby interfere with the entry of other ER ligands or with the mobility of helix 12, either of which actions could explain phenytoin's antagonism of ER-mediated E2 actions. Our results suggest an explanation for the broad profile of phenytoin's actions and raise possibilities for the use of phenytoin or congeners in the clinical management of ERα-dependent conditions.

Mechanisms of levetiracetam in the control of status epilepticus and epilepsy

Status epilepticus (SE) is a major clinical emergency that is associated with high mortality and morbidity. SE causes significant neuronal injury and survivors are at a greater risk of developing acquired epilepsy and other neurological morbidities, including depression and cognitive deficits. Benzodiazepines and some anticonvulsant agents are drugs of choice for initial SE management. Despite their effectiveness, over 40% of SE cases are refractory to the initial treatment with two or more medications. Thus, there is an unmet need of developing newer anti-SE drugs. Levetiracetam (LEV) is a widely prescribed anti-epileptic drug that has been reported to be used in SE cases, especially in benzodiazepine-resistant SE or where phenytoin cannot be used due to allergic side-effects. Levetiracetam’s non-classical anti-epileptic mechanisms of action, favorable pharmacokinetic profile, general lack of central depressant effects, and lower incidence of drug interactions contribute to its use in SE management. This review will focus on LEV’s unique mechanism of action that makes it a viable candidate for SE treatment.

Post-traumatic epilepsy: current and emerging treatment options

Traumatic brain injury (TBI) leads to many undesired problems and complications, including immediate and long-term seizures/epilepsy, changes in mood, behavioral, and personality problems, cognitive and motor deficits, movement disorders, and sleep problems. Clinicians involved in the treatment of patients with acute TBI need to be aware of a number of issues, including the incidence and prevalence of early seizures and post-traumatic epilepsy (PTE), comorbidities associated with seizures and anticonvulsant therapies, and factors that can contribute to their emergence. While strong scientific evidence for early seizure prevention in TBI is available for phenytoin (PHT), other antiepileptic medications, eg, levetiracetam (LEV), are also being utilized in clinical settings. The use of PHT has its drawbacks, including cognitive side effects and effects on function recovery. Rates of recovery after TBI are expected to plateau after a certain period of time. Nevertheless, some patients continue to improve while others deteriorate without any clear contributing factors. Thus, one must ask, 'Are there any actions that can be taken to decrease the chance of post-traumatic seizures and epilepsy while minimizing potential short- and long-term effects of anticonvulsants?' While the answer is 'probably,' more evidence is needed to replace PHT with LEV on a permanent basis. Some have proposed studies to address this issue, while others look toward different options, including other anticonvulsants (eg, perampanel or other AMPA antagonists), or less established treatments (eg, ketamine). In this review, we focus on a comparison of the use of PHT versus LEV in the acute TBI setting and summarize the clinical aspects of seizure prevention in humans with appropriate, but general, references to the animal literature.