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Papers by cliff eastman

Annals of Neurology, 2012

Epilepsia, Feb 12, 2023

ObjectiveFor an antiseizure medication (ASM) to be effective in status epilepticus (SE), the drug... more ObjectiveFor an antiseizure medication (ASM) to be effective in status epilepticus (SE), the drug should be administered intravenously (i.v.) to provide quick access to the brain. However, poor aqueous solubility is a major problem in the development of parenteral drug solutions. Given its multiple mechanisms of action, topiramate (TPM) is a promising candidate for the treatment of established or refractory SE, as supported by clinical studies using nasogastric tube TPM administration. However, TPM is not clinically available as a solution for i.v. administration, which hampers its use in the treatment of SE. Here, we describe a novel easy‐to‐use and easy‐to‐prepare i.v. TPM formulation using the U.S. Food and Drug Administration (FDA)–approved excipient meglumine.MethodsDuring formulation development, we compared the solubility of TPM in bi‐distilled water with vs without a range of meglumine concentrations. Furthermore, the solubility of combinations of TPM and levetiracetam and TPM, levetiracetam, and atorvastatin in aqueous meglumine concentrations was determined. Subsequently, the pharmacokinetics and tolerability of meglumine‐based solutions of TPM and TPM combinations were evaluated in rats, including animals following fluid percussion injury or pilocarpine‐induced SE.ResultsThe amino sugar meglumine markedly enhances the aqueous solubility of TPM. A comparison with data on dissolving TPM using sulfobutylether‐β‐cyclodextrin (Captisol) demonstrates that meglumine is much more effective for dissolving TPM. Furthermore, meglumine can be used to prepare drug cocktails where TPM is co‐administered with another ASM for SE treatment. The tolerability studies of the meglumine‐based TPM solution and meglumine‐based TPM combinations in normal rats and the rat fluid percussion injury and pilocarpine‐induced SE models demonstrate excellent tolerability of the novel drug solutions. Preclinical studies on antiseizure efficacy in the SE model are underway.SignificanceIn conclusion, the novel meglumine‐based solution of TPM presented here may be well suited for clinical development.

Neuropharmacology, 2019

Modulating neuroinflammation and oxidative stress to prevent epilepsy and improve outcomes after ... more Modulating neuroinflammation and oxidative stress to prevent epilepsy and improve outcomes after traumatic brain injury, (2019), Neuropharmacology

J Pharmacol Exp Ther ., 2011

Carisbamate (CRS) exhibits broad acute anticonvulsant activity in conventional anticonvulsant scr... more Carisbamate (CRS) exhibits broad acute anticonvulsant activity in conventional anticonvulsant screens, genetic models of absence epilepsy and audiogenic seizures, and chronic spontaneous motor seizures arising after chemoconvulsant-induced status epilepticus. In add-on phase III trials with pharmacoresistant patients CRS induced Ͻ30% average decreases in partial-onset seizure frequency. We assessed the antiepileptogenic and antiepileptic performance of subchronic CRS administration on posttraumatic epilepsy (PTE) induced by rostral parasaggital fluid percussion injury (rpFPI), which closely replicates human contusive closed head injury. Studies were blind and randomized, and treatment effects were assessed on the basis of sensitive electrocorticography (ECoG) recordings. Antiepileptogenic effects were assessed in independent groups of control and CRS-treated rats, at 1 and 3 months postinjury, after completion of a 2-week prophylactic treatment initiated 15 min after injury. The antiepileptic effects of 1-week CRS treatments were assessed in repeated measures experiments at 1 and 4 months postinjury. The studies were powered to detect ϳ50 and ϳ40% decreases in epilepsy incidence and frequency of seizures, respectively. Drug/vehicle treatment, ECoG analysis, and [CRS] plasma determination all were performed blind. We detected no antiepileptogenic and an equivocal transient antiepileptic effects of CRS despite [CRS] plasma comparable with or higher than levels attained in previous preclinical and clinical studies. These findings contrast with previous preclinical data demonstrating large efficacy of CRS, but agree with the average effect of CRS seen in clinical trials. The data support the use of rpFPI-induced PTE in the adolescent rat as a model of pharmacoresistant epilepsy for preclinical development.

Exp. Neurol., 2010

The use of electrocorticography (ECoG) with etiologically realistic epilepsy models promises to f... more The use of electrocorticography (ECoG) with etiologically realistic epilepsy models promises to facilitate the discovery of better anti-epileptic drugs (AEDs). However, this novel approach is labor intensive, and must be optimized. To this end, we employed rostral parasagittal fluid percussion injury (rpFPI) in the adolescent rat, which closely replicates human contusive closed head injury and results in posttraumatic epilepsy (PTE). We systematically examined variables affecting the power to detect anti-epileptic effects by ECoG and used a non-parametric bootstrap strategy to test several different statistics, study designs, statistical tests, and impact of non-responders. We found that logarithmically transformed data acquired in repeated-measures experiments provided the greatest statistical power to detect decreases in seizure frequencies of preclinical interest with just 8 subjects and with up to ∼ 40% non-responders. We then used this optimized design to study the anti-epileptic effects of acute exposure to halothane, and chronic (1 week) exposures to carbamazepine (CBZ) and valproate (VPA) 1 month post-injury. While CBZ was ineffective in all animals, VPA induced, during treatment, a progressive decrease in seizure frequency in animals primarily suffering from non-spreading neocortical seizures, but was ineffective in animals with a high frequency of spreading seizures. Halothane powerfully blocked all seizure activity. The data show that rpFPI and chronic ECoG can conveniently be employed for the evaluation of AEDs, suggest that VPA may be more effective than CBZ to treat some forms of PTE, and support the theory that pharmacoresistance may depend on the severity of epilepsy. The data also demonstrate the utility of chronic exposures to experimental drugs in preclinical studies and highlight the need for greater attention to etiology in clinical studies of AEDs.

J. Neurophysiol, 2010

Chronic dysfunction of astrocytic inwardly rectifying K ϩ channels specific to the neocortical ep... more Chronic dysfunction of astrocytic inwardly rectifying K ϩ channels specific to the neocortical epileptic focus after fluid percussion injury in the rat. J Neurophysiol

Post-traumatic epilepsy is prevalent, often difficult to manage, and currently cannot be prevente... more Post-traumatic epilepsy is prevalent, often difficult to manage, and currently cannot be prevented. Although cooling is broadly neuroprotective, cooling-induced prevention of chronic spontaneous recurrent seizures has never been demonstrated. We examined the effect of mild passive focal cooling of the perilesional neocortex on the development of neocortical epileptic seizures after head injury in the rat. Methods: Rostral parasagittal fluid percussion injury in rats reliably induces a perilesional, neocortical epileptic focus within weeks after injury. Epileptic seizures were assessed by 5-electrode video-electrocorticography (ECoG) 2 to 16 weeks postinjury. Focal cooling was induced with ECoG headsets engineered for calibrated passive heat dissipation. Pathophysiology was assessed by glial fibrillary acidic protein immunostaining, cortical sclerosis, gene expression of inflammatory cytokines interleukin (IL)-1a and IL-1b, and ECoG spectral analysis. All animals were formally randomized to treatment groups, and data were analyzed blind. Results: Cooling by 0.5 to 2 C inhibited the onset of epileptic seizures in a dose-dependent fashion. The treatment induced no additional pathology or inflammation, and normalized the power spectrum of stage N2 sleep. Cooling by 2 C for 5.5 weeks beginning 3 days after injury virtually abolished ictal activity. This effect persisted through the end of the study, >10 weeks after cessation of cooling. Rare remaining seizures were shorter than in controls. Interpretation: These findings demonstrate potent and persistent prevention and modification of epileptic seizures after head injury with a cooling protocol that is neuroprotective, compatible with the care of head injury patients, and conveniently implemented. The required cooling can be delivered passively without Peltier cells or electrical power.

Exp. Neurol., 2015

Conventionally developed antiseizure drugs fail to control epileptic seizures in about 30% of pat... more Conventionally developed antiseizure drugs fail to control epileptic seizures in about 30% of patients, and no treatment prevents epilepsy. New etiologically realistic, syndrome-specific epilepsy models are expected to identify better treatments by capturing currently unknown ictogenic and epileptogenic mechanisms that operate in the corresponding patient populations. Additionally, the use of electrocorticography permits better monitoring of epileptogenesis and the full spectrum of acquired seizures, including focal nonconvulsive seizures that are typically difficult to treat in humans. Thus, the combined use of etiologically realistic models and electrocorticography may improve our understanding of the genesis and progression of epilepsy, and facilitate discovery and translation of novel treatments. However, this approach is labor intensive and must be optimized. To this end, we used an etiologically realistic rat model of posttraumatic epilepsy, in which the initiating fluid percussion injury closely replicates contusive closed-head injury in humans, and has been adapted to maximize epileptogenesis and focal non-convulsive seizures. We obtained week-long 5-electrode electrocorticography 1 month post-injury, and used a Monte-Carlo-based non-parametric bootstrap strategy to test the impact of electrode montage design, duration-based seizure definitions, group size and duration of recordings on the assessment of posttraumatic epilepsy, and on statistical power to detect antiseizure and antiepileptogenic treatment effects. We found that use of seizure definition based on clinical criteria rather than event duration, and of recording montages closely sampling the activity of epileptic foci, maximize the power to detect treatment effects. Detection of treatment effects was marginally improved by prolonged recording, and 24 h recording epochs were sufficient to provide 80% power to detect clinically interesting seizure control or prevention of seizures with small groups of animals. We conclude that appropriate electrode montage and clinically relevant seizure definition permit convenient deployment of fluid percussion injury and electrocorticography for epilepsy therapy development.

Neuropharmacology, 2020

• Reactive oxygen species (ROS) and neuroinflammation contribute to the secondary injury after tr... more • Reactive oxygen species (ROS) and neuroinflammation contribute to the secondary injury after traumatic brain injury (TBI). • ROS-induced cytotoxicity and dysregulation of redox-regulated processes both contribute to secondary injury after TBI. • Oxidative stress / ROS generation and inflammation are highly interdependent and mutually reinforcing after TBI. • Targeting both ROS generation and inflammation may synergize to reduce secondary injury and prevent epilepsy after TBI.

Expert Rev Neurother . , 2013

Currently available epilepsy drugs only affect the symptoms (seizures), and there is a need for i... more Currently available epilepsy drugs only affect the symptoms (seizures), and there is a need for innovative treatments that target the underlying disease. Increasing evidence points to inflammation as a potentially important mechanism in epileptogenesis. In the last decade, a new generation of etiologically realistic syndrome-specific experimental models have been developed which are expected to capture the epileptogenic mechanisms operating in the corresponding patient populations, and to exhibit similar treatment-responsiveness. Recently, an intervention known have broad-ranging anti-inflammatory effects (selective brain cooling) has been found to prevent the development of spontaneously occurring seizures in an etiologically realistic rat model of post-traumatic epilepsy. Several drugs used clinically for other indications also have the potential for inhibiting inflammation, and should be investigated for anti-epileptogenic activity in these models. If results of such studies are positive, these compounds could enter rapidly Phase III trials in patients at high risk of developing epilepsy.

Translational Research in Traumatic Brain Injury, 2016

Experimental animals' seizures are often defined arbitrarily based on duration, which may lead to... more Experimental animals' seizures are often defined arbitrarily based on duration, which may lead to misjudgement of the syndrome and failure to develop a cure. We employed a functional definition of seizures based on the clinical practice of observing epileptiform electrocorticography and simultaneous ictal behaviour, and examined post-traumatic epilepsy induced in rats by rostral parasagittal fluid percussion injury and epilepsy patients evaluated with invasive monitoring. We showed previously that rostral parasagittal fluid percussion injury induces different types of chronic recurrent spontaneous partial seizures that worsen in frequency and duration over the months post injury. However, a remarkable feature of rostral parasagittal fluid percussion injury is the occurrence, in the early months post injury, of brief (52 s) focal, recurrent and spontaneous epileptiform electrocorticography events (EEEs) that are never observed in sham-injured animals and have electrographic appearance similar to the onset of obvious chronic recurrent spontaneous partial seizures. Simultaneous epidural-electrocorticography and scalpelectroencephalography recordings in the rat demonstrated that these short EEEs are undetectable by scalp electrocorticography. Behavioural analysis performed blinded to the electrocorticography revealed that (i) brief EEEs lasting 0.8-2 s occur simultaneously with behavioural arrest; and (ii) while behavioural arrest is part of the rat's behavioural repertoire, the probability of behavioural arrest is greatly elevated during EEEs. Moreover, spectral analysis showed that EEEs lasting 0.8-2 s occurring during periods of active behaviour with dominant theta activity are immediately followed by loss of such theta activity. We thus conclude that EEEs lasting 0.8-2 s are ictal in the rat. We demonstrate that the assessment of the time course of fluid percussion injury-induced epileptogenesis is dramatically biased by the definition of seizure employed, with common duration-based arbitrary definitions resulting in artificially prolonged latencies for epileptogenesis. Finally, we present four human examples of electrocorticography capturing short (52 s), stereotyped, neocortically generated EEEs that occurred in the same ictal sites as obvious complex partial seizures, were electrographically similar to rat EEEs and were not noted during scalp electroencephalography. When occurring in the motor cortex, these short EEEs were accompanied by ictal behaviour detectable with simultaneous surface electromyography. These data demonstrate that short (52 s) focal recurrent spontaneous EEEs are seizures in both rats and humans, that they are undetectable by scalp electroencephalography, and that they are typically associated with subtle and easily missed behavioural correlates. These findings define the earliest identifiable markers of progressive post-traumatic