Pretreatment with intravenous levetiracetam in the rhesus monkey Coriaria lactone-induced status epilepticus model

Emerging Electroencephalographic Biomarkers to Improve Preclinical to Clinical Translation in Alzheimer’s Disease

Continually emerging data indicate that sub-clinical, non-convulsive epileptiform activity is not only prevalent in Alzheimer’s disease (AD) but is detectable early in the course of the disease and predicts cognitive decline in both humans and animal models. Epileptiform activity and other electroencephalographic (EEG) measures may hold powerful, untapped potential to improve the translational validity of AD-related biomarkers in model animals ranging from mice, to rats, and non-human primates. In this review, we will focus on studies of epileptiform activity, EEG slowing, and theta-gamma coupling in preclinical models, with particular focus on its role in cognitive decline and relevance to AD. Here, each biomarker is described in the context of the contemporary literature and recent findings in AD relevant animal models are discussed.

Behavioral and Brain Structural Changes in Kindled Rats Induced by Coriaria Lactone/Pentylenetetrazol

Epilepsy is a common chronic neurological disease that is characterized by spontaneous seizures. It is commonly comorbid with behavioral and mood disorders. No studies have yet examined the behavioral or structural brain changes associated with coriaria lactone (CL)-induced and pentylenetetrazol (PTZ)-induced kindlings. This study examined whether the increased seizure susceptibility induced by CL/PTZ is accompanied by behavioral impairments and aimed to identify associated structural brain changes. Kindling models were induced using CL and PTZ, with 10 rats in each group. After successful kindling, rats were subjected to brain structural imaging using T2-weighted imaging and underwent behavioral tests, namely, the open field test, water maze tasks, and contextual fear conditioning. Voxel-based morphometry was then used to identify possible brain structural changes associated with kindling and/or behaviors. Support-vector machine learning was also applied for the integrative analysis of behavioral changes and structural brain imaging. In the open field test, both the CL (P = 0.04) and PTZ groups (P = 0.002) spent more time in the central area than the control group. Only the PTZ group (50.29 ± 29.56 s) showed a freezing time that was significantly less than that of the control group (94.8 ± 41.04 s; P = 0.024, Tukey's HSD-corrected) in contextual fear conditioning, which is suggestive of impaired fear-associated learning ability. Furthermore, brain imaging analysis revealed that the gray matter volume (GMV) of the hippocampus changed in both the CL and PTZ groups when compared to control. The support-vector machine learning model indicated that the retrosplenial dysgranular and primary somatosensory cortices were associated with both of the mentioned kindling models. Furthermore, the support-vector regression model results indicated that kindling-associated GMV changes can be used to predict general exploratory activity in the open field test. In conclusion, this is the first study to report greater general exploratory activity in a CL-induced kindling model. Moreover, the general exploratory activity in the open field test can be predicted by the GMV of brain regions associated with kindling.

Effects of early noise exposure on hippocampal-dependent behaviors during adolescence in male rats: influence of different housing conditions

Central nervous system (CNS) development is a very complex process that can be altered by environmental stimuli such as noise, which can generate long-term auditory and/or extra-auditory impairments. We have previously reported that early noise exposure can induce hippocampus-related behavioral alterations in postnatal day (PND) 28 adolescent rats. Furthermore, we recently found biochemical modifications in the hippocampus (HC) of these animals that seemed to endure even in more mature animals (i.e. PND35) and that have not been studied along with behavioral correlates. Thus, the aim of this work was to reveal novel data about the effects of early noise exposure on hippocampal-dependent behaviors in more mature animals. Additionally, extended enriched environment (EE) housing was evaluated to determine its capacity to induce behavioral modifications, either by its neuroprotective ability or the greater stimulation that it generates. Male Wistar rats were exposed to different noise schemes at PND7 or PND15. Upon weaning, some animals were transferred to EE whereas others were kept in standard cages. At PND35, different hippocampal-dependent behavioral assessments were performed. Results showed noise-induced behavioral changes that differed according to the scheme and age of exposure used. In addition, housing in an EE was effective either in preventing some of these changes or in inducing the appearance of new behavioral modifications. These findings suggest that CNS development would be sensitive to the effects of different type of environmental stimuli such as noise or enriched housing, leading to maladaptive behavioral changes that last even until adolescence.

Brain functional and structural characteristics of patients with seizure recurrence following drug withdrawal

PURPOSE

We aimed to analyze the characteristics of brain function and microstructure linked to epilepsy relapse after drug withdrawal in patients with focal epilepsy.

METHODS

Resting-state functional magnetic resonance imaging and high-resolution T1-weighted images were acquired within 1 month prior to drug withdrawal from 15 patients who did not have epilepsy relapse (PER - group) and 16 patients who subsequently had epilepsy relapse (PER + group). Additionally, 23 healthy participants undergoing the same scanning protocol were included as controls. Fractional amplitude of low-frequency fluctuation (fALFF) and gray matter density (GMD) were compared among groups. Subgroup and correlation analyses were also performed.

RESULTS

There were no significant differences in fALFF between patient groups, but the PER + group showed lower GMD in the bilateral calcarine, left precuneus, and right superior temporal gyrus than the PER - group (Gaussian random field correction, voxel-level P < 0.001 and cluster-level P < 0.05). Both increased seizure number and polytherapy were associated with lower GMD; also, patients using other antiseizure medications showed lower GMD than those using only levetiracetam (Gaussian random field correction, voxel-level P < 0.001, and cluster-level P < 0.05). The active period and disease duration showed both positive and negative correlations with GMD, while the seizure-free period mainly showed positive correlations with GMD (uncorrected, P < 0.001).

CONCLUSION

Gray matter microstructure, but not local functional activity, showed distinct characteristics between patients with and without epilepsy relapse and may serve as a potential biomarker for predicting seizure recurrence upon drug withdrawal.

Microstructural features of the cerebral cortex: Implications for predicting epilepsy relapse after drug withdrawal

A considerable portion of patients with well-controlled seizures and visually normal brain structures experience seizure recurrence after anti-seizure medication is withdrawn. Microstructural abnormalities of the cortex may play an essential role in epilepsy relapse. Patients with idiopathic/cryptogenic epilepsy were registered. At the follow-up endpoint, 18 patients with relapse (PR+ group), 20 patients without relapse (PR- group), and 30 healthy controls were included. High-resolution T1-weighted images were obtained at the time of drug withdrawal. Microstructural features including cortical thickness, surface area, cortical volume and mean curvature in 68 cortical areas were calculated. A general linear model was applied to investigate intergroup differences, and then post hoc analysis was performed. Additionally, factor analysis was conducted to extract components from imaging measures showing a difference between PR- and PR+ groups, and independent associations between components and epilepsy relapse were assessed using a logistic regression model. Cortical thickness of the left paracentral lobule, left temporal pole and right superior frontal gyrus; surface area of the bilateral lingual gyrus and bilateral pericalcarine cortex; and cortical volume of the bilateral pericalcarine cortex had significant intergroup differences (false discovery rate correction, P < 0.05). All measures, except for cortical thickness of the left temporal pole, showed differences between PR- and PR+ groups. Two dominant components were extracted from these measures, and both were independently associated with epilepsy relapse. In conclusion, epilepsy patients with relapse presented distinct microstructural features of cortex at the time of drug withdrawal, which may serve as a potential biomarker for predicting seizure recurrence.

Levetiracetam administration is correlated with lower mortality in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes: a retrospective study

Background:

Studies on the relationship between antiepileptic drug (AED) administration and clinical outcomes in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) remain scarce. Levetiracetam (LEV) is an AED that is neuroprotective in various neurologic disorders. This study aimed to determine the impact of LEV on the outcome of MELAS.

Methods:

A retrospective, single-center study was performed based on a large cohort of patients with MELAS with a history of seizures (n = 102). Decisions on antiepileptic therapies were made empirically. Patients were followed up for 1 to 8 years (median, 4 years) and divided into 2 groups based on whether LEV was administered (LEV or non-LEV). The modified Rankin scale (mRS) scores and mortality risks were analyzed in all patients.

Results:

LEV, carbamazepine, benzodiazepines, topiramate, oxcarbazepine, valproate, and lamotrigine were administered in 48, 37, 18, 13, 11, 9, and 9 patients, singly or in combination, respectively. The mean mRS score of the LEV group (n = 48) was lower than that of the non-LEV group (n = 54; mean ± standard deviation, 2.79 ± 1.47 vs. 3.83 ± 1.93, P = 0.006) up to the end of the study. Nevertheless, there was no difference in the proportion of subjects without disability (mRS ranging 0–1) between the groups (P = 0.37). The multivariate regressions revealed that LEV treatment was associated with lower mRS scores (odds ratio 0.32, 95% confidence interval [CI] 0.15–0.68, P = 0.003) and mortality rates (hazard ratio 0.24, 95% CI 0.08–0.74, P = 0.013). There was a significant difference in the Kaplan-Meier survival curves between the groups (χ² = 4.29, P = 0.04).

Conclusions:

The LEV administration is associated with lower mortality in patients with MELAS in this retrospective study. Further laboratory research and prospective cohort studies are needed to confirm whether LEV has neuroprotective effects on patients with mitochondrial diseases.

A Comparison of Intravenous Levetiracetam and Valproate for the Treatment of Refractory Status Epilepticus in Children

Because of the lack of studies comparing the efficacy and safety of levetiracetam and valproate before the induction of general anesthesia in the treatment of convulsive refractory status epilepticus in children, we aimed to compare the effectiveness of these antiepileptic drugs in patients with convulsive status epilepticus admitted to the Pediatric Intensive Care Unit between 2011 and 2014. Forty-six (59%) of the 78 patients received levetiracetam, and 32 (41%) received valproate for the treatment of refractory status epilepticus. The response rate was not significantly different between the 2 groups. Although no adverse event was noted in patients who received levetiracetam, 4 (12.5%) patients in the valproate group experienced liver dysfunction (P = .025). According to our results, levetiracetam and valproate may be used in the treatment of refractory status epilepticus before the induction of general anesthesia. Levetiracetam appears as effective as valproate, and also safer.