Effects of levetiracetam on blood-brain barrier disturbances following hyperthermia-induced seizures in rats with cortical dysplasia

IL-17A Aggravated Blood-Brain Barrier Disruption via Activating Src Signaling in Epilepsy Mice

Inflammation is an important pathogenic driving force in the genesis and development of epilepsy. The latest researches demonstrated that IL-17A mediated blood-brain barrier (BBB) dysfunction through disruption of tight junction protein expression. To investigate whether IL-17A is involved in BBB disruption after acute seizure attack, the pilocarpine model was established with C57BL/6 J (wild type, WT) and IL-17R-deficient mice in vivo and with primary cultured rat brain microvascular endothelial cells in vitro. The mortality rate and brain water content were evaluated at 24 h after status epilepticus, and IL-17A concentration, endothelial tight junction, adherens junction proteins, and albumin leakage were assessed at 0 h, 4 h, 12 h, and 24 h after status epilepticus (SE). IL-17R-deficient mice showed lessen severity of epilepsy than WT mice, accompanied by less albumin leakage, reduced brain water content, decreased IL-17A, and upregulated expression of target proteins (ZO-1, Occludin and VE-cadherin). IL-17R knockout abrogated abnormal upregulation of Src kinase and phosphorylated Src kinase in the setting of SE, and Src kinase inhibitor PP1 abrogated IL-17A-induced SE related endothelial injury in vitro. In conclusion, IL-17A inhibition might be a promising therapeutic option to attenuate endothelial cell injury and further BBB disruption by reducing Src kinase activation.

Feeding metformin during pregnancy and lactation periods improved learning and memory impairment in the rat offspring exposed to febrile seizure: Role of oxidative stress and inflammatory response

BACKGROUND

Many clinical evidences have reported the higher risk of seizure in young children and infants after exposure to hyperthermia, which more likely can cause brain damage and affect cognitive function, so, many researches were focused on prevention or treatment of febrile seizure (FS) with minimal adverse effects. Considering the potential effects of oxidative stress as a prominent trigger in FS, and demonstrating the anti-oxidant effects of metformin, the present study aimed to investigate the protective effect of metformin administration in prenatal and lactation periods in rat pups exposed to hyperthermia by which induced seizure.

METHOD AND MATERIALS

Pregnant rats were divided into six groups: (1) vehicle: pregnant rats received normal saline during pregnancy and lactation; (2) FS: pregnant rats received normal saline during pregnancy and lactation; (3-5) FS-Met50/100/150 mg/kg: pregnant rats received different doses of metformin including 50, 100 and 150 mg/kg during pregnancy and lactation; (6) Met150 mg/kg: pregnant rats received Met150 mg/kg during pregnancy and lactation. The male pups born to mothers received in all FS groups exposed to hyperthermia. All experimental groups were allowed to grow up, and after the lactation period, they were subjected for behavioural tests and biochemical analysis.

RESULTS

According to the present findings, the prenatal and lactation exposure to the highest dose of metformin demonstrated significant difference with FS group in both behavioural and biochemical test analyses. Although the remaining doses of metformin were also effective, the much better results were reported with the highest dose of metformin (150 mg/kg). Interestingly, the highest dose of metformin administered alone demonstrated better result than vehicle in probe trial test.

CONCLUSION

Considering the present research and related study in relation to metformin in ameliorating the epilepsy symptoms, there are numerous evidences on positive effect of metformin on seizure. Although the exact mechanism is unclear, the anti-oxidant effect of metformin is strongly supported.

Early preclinical plasma protein biomarkers of brain trauma are influenced by early seizures and levetiracetam

OBJECTIVE

We used the lateral fluid percussion injury (LFPI) model of moderate-to-severe traumatic brain injury (TBI) to identify early plasma biomarkers predicting injury, early post-traumatic seizures or neuromotor functional recovery (neuroscores), considering the effect of levetiracetam, which is commonly given after severe TBI.

METHODS

Adult male Sprague-Dawley rats underwent left parietal LFPI, received levetiracetam (200 mg/kg bolus, 200 mg/kg/day subcutaneously for 7 days [7d]) or vehicle post-LFPI, and were continuously video-EEG recorded (n = 14/group). Sham (craniotomy only, n = 6), and naïve controls (n = 10) were also used. Neuroscores and plasma collection were done at 2d or 7d post-LFPI or equivalent timepoints in sham/naïve. Plasma protein biomarker levels were determined by reverse phase protein microarray and classified according to injury severity (LFPI vs. sham/control), levetiracetam treatment, early seizures, and 2d-to-7d neuroscore recovery, using machine learning.

RESULTS

Low 2d plasma levels of Thr231 -phosphorylated tau protein (pTAU-Thr231 ) and S100B combined (ROC AUC = 0.7790) predicted prior craniotomy surgery (diagnostic biomarker). Levetiracetam-treated LFPI rats were differentiated from vehicle treated by the 2d-HMGB1, 2d-pTAU-Thr231 , and 2d-UCHL1 plasma levels combined (ROC AUC = 0.9394) (pharmacodynamic biomarker). Levetiracetam prevented the seizure effects on two biomarkers that predicted early seizures only among vehicle-treated LFPI rats: pTAU-Thr231 (ROC AUC = 1) and UCHL1 (ROC AUC = 0.8333) (prognostic biomarker of early seizures among vehicle-treated LFPI rats). Levetiracetam-resistant early seizures were predicted by high 2d-IFNγ plasma levels (ROC AUC = 0.8750) (response biomarker). 2d-to-7d neuroscore recovery was best predicted by higher 2d-S100B, lower 2d-HMGB1, and 2d-to-7d increase in HMGB1 or decrease in TNF (P < 0.05) (prognostic biomarkers).

SIGNIFICANCE

Antiseizure medications and early seizures need to be considered in the interpretation of early post-traumatic biomarkers.

Prognostic effects of treatment protocols for febrile convulsive status epilepticus in children

Background

Febrile status epilepticus is the most common form of status epilepticus in children. No previous reports compare the effectiveness of treatment strategies using fosphenytoin (fPHT) or phenobarbital (PB) and those using anesthetics as second-line anti-seizure medication for benzodiazepine-resistant convulsive status epilepticus (CSE). We aimed to examine the outcomes of various treatment strategies for febrile convulsive status epilepticus (FCSE) in a real-world setting while comparing the effects of different treatment protocols and their presence or absence.

Methods

This was a single-center historical cohort study that was divided into three periods. Patients who presented with febrile convulsive status epilepticus for ≥60 min even after the administration of at least one anticonvulsant were included. During period I (October 2002–December 2006), treatment was performed at the discretion of the attending physician, without a protocol. During period II (January 2007–February 2013), barbiturate coma therapy (BCT) was indicated for FCSE resistant to benzodiazepines. During period III (March 2013–April 2016), BCT was indicated for FCSE resistant to fPHT or PB.

Results

The rate of electroencephalogram monitoring was lower in period I than period II+III (11.5% vs. 85.7%, p<0.01). Midazolam was administered by continuous infusion more often in period I than period II+III (84.6% vs. 25.0%, p<0.01), whereas fPHT was administered less often in period I than period II+III (0% vs. 27.4%, p<0.01). The rate of poor outcome, which was determined using the Pediatric Cerebral Performance Category scale, was higher in period I than period II+III (23.1% vs. 7.1%, p=0.03). The rate of poor outcome did not differ between periods II and III (4.2% vs. 11.1%, p=0.40).

Conclusions

While the presence of a treatment protocol for FCSE in children may improve outcomes, a treatment protocol using fPHT or PB may not be associated with better outcomes.

Visualization of blood-brain barrier disruption with dual-wavelength high-resolution photoacoustic microscopy

The blood-brain barrier (BBB) strictly regulates the substance exchange between the vascular network and the central nervous system, and plays a critical role in maintaining normal brain homeostasis. Impaired BBB is often accompanied with the emergence of cerebral diseases and probably further leads to severe neuroinflammation or even neurological degeneration. Hence, there is an urgent need to precisely monitor the impaired BBB to understand its pathogenesis and better guide the enactment of therapeutic strategies. However, there is a lack of high-resolution imaging techniques to visualize and evaluate the large-scale BBB disruption in pre-clinical and clinical aspects. In this study, we propose a dual-wavelength photoacoustic imaging (PAI) methodology that simultaneously reveals the abnormal microvasculature and impaired BBB within the cerebral cortex. In in vivo studies, BBB disruption in both mice and rats were induced by local hot-water stimulation and unilateral carotid arterial perfusion of hyperosmolar mannitol, respectively. Subsequently, the exogenous contrast agent (CA) was injected into the microcirculation via the tail vein, and photoacoustic (PA) images of the microvasculature and leaked CA within the cerebral cortex were obtained by dual-wavelength photoacoustic microscopy to evaluate the BBB disruption. Besides, analysis of distribution and concentration of leaked CA in lesion region was further conducted to quantitatively reveal the dynamic changes of BBB permeability. Furthermore, we exploited this approach to investigate the reversibility of BBB disruption within the two distinct models. Based on the experimental results, this new proposed approach presents excellent performance in visualizing microvasculature and leaked CA, and enabling it possesses great potential in evaluating the abnormal microvasculature and impaired BBB result from cerebrovascular diseases.

Basic physiology of the blood-brain barrier in health and disease: a brief overview

The blood-brain barrier (BBB), a dynamic interface between blood and brain constituted mainly by endothelial cells of brain microvessels, robustly restricts the entry of potentially harmful blood-sourced substances and cells into the brain, however, many therapeutically active agents concurrently cannot gain access into the brain at effective doses in the presence of an intact barrier. On the other hand, breakdown of BBB integrity may involve in the pathogenesis of various neurodegenerative diseases. Besides, certain diseases/disorders such as Alzheimer's disease, hypertension, and epilepsy are associated with varying degrees of BBB disruption. In this review, we aim to highlight the current knowledge on the cellular and molecular composition of the BBB with special emphasis on the major transport pathways across the barrier type endothelial cells. We further provide a discussion on the innovative brain drug delivery strategies in which the obstacle formed by BBB interferes with effective pharmacological treatment of neurodegenerative diseases/disorders.

Clinical characteristics and electroencephalogram analysis of levetiracetam in the treatment of children with febrile seizure recurrence

Febrile seizure is the most common neurologic disorder in infants and children. This study aimed to elaborate safe and effective therapy for preventing FS recurrence by levetiracetam (LEV). A prospective study was performed in two groups of children, the no treatment group (n=51, 24.1±9.0 months) and the LEV treatment group (n=45, 23.3±8.9 months). The findings demonstrated that a significant difference (P<0.01) was observed between the no treatment group 51.0% (26/51) and LEV treatment group 15.5% (7/45) in terms of FS recurrence after 50 weeks. FS recurrence/fever episode was 12.4% (12/97) in the LEV treatment group and 51.8% (57/110) in the no treatment group. Furthermore, LEV administration significantly improved (P<0.001) epileptiform + nonspecific EEG abnormalities (17.8%; 8/45), as compared with the no treatment group (68.6%; 35/51). In conclusion, LEV could function as an effective therapeutic agent for the prevention of FS recurrence and reducing the frequency of fever episodes. Furthermore, LEV administration significantly improved nonspecific EEG abnormalities, which may be used as a clinical monitoring index for LEV treatment in patients with FS.

Preserving brain function in a comatose patient with septic hyperpyrexia (41.6 °C): a case report

Background

Pyrexia is a physiological response through which the immune system responds to infectious processes. Hyperpyrexia is known to be neurodegenerative leading to brain damage. Some of the neurotoxic effects of hyperpyrexia on the brain include seizures, decreased cognitive speed, mental status changes, coma, and even death. In the clinical management of hyperpyrexia, the goal is to treat the underlying cause of elevated temperature and prevent end organ damage.

Case presentation

This case illustrates a 39-year-old white American man referred from another medical facility where he had undergone an upper gastrointestinal tract diagnostic procedure which became complicated by blood aspiration and respiratory distress. During hospitalization, he developed a core body temperature of 41.6 °C (106.9 °F) leading to cognitive decline and coma with a Glasgow Coma Score of 3. Levetiracetam and amantadine were utilized effectively for preserving and restoring neurocognitive function. Prior studies have shown that glutamate levels can increase during an infectious process. Glutamate is an excitatory neurotransmitter that is utilized by the organum vasculosum laminae terminalis through the neuronal excitatory system and causes an increase in body temperature which can lead to hyperpyrexia. Similar to neurogenic fevers, hyperpyrexia can lead to neurological decline and irreversible cognitive dysfunction. Inhibition of the glutamate aids a decrease in excitatory states, and improves the brain’s regulatory mechanism, including temperature control. To further improve cognitive function, dopamine levels were increased with a dopamine agonist.

Conclusions

We propose that a combination of levetiracetam and amantadine may provide neuroprotective and neurorestorative properties when administered during a period of hyperpyrexia accompanied by any form of mental status changes, particularly if there is a decline in Glasgow Coma Score.

Preserving brain function in a comatose patient with septic hyperpyrexia (41.6 °C): a case report

BACKGROUND

Pyrexia is a physiological response through which the immune system responds to infectious processes. Hyperpyrexia is known to be neurodegenerative leading to brain damage. Some of the neurotoxic effects of hyperpyrexia on the brain include seizures, decreased cognitive speed, mental status changes, coma, and even death. In the clinical management of hyperpyrexia, the goal is to treat the underlying cause of elevated temperature and prevent end organ damage.

CASE PRESENTATION

This case illustrates a 39-year-old white American man referred from another medical facility where he had undergone an upper gastrointestinal tract diagnostic procedure which became complicated by blood aspiration and respiratory distress. During hospitalization, he developed a core body temperature of 41.6 °C (106.9 °F) leading to cognitive decline and coma with a Glasgow Coma Score of 3. Levetiracetam and amantadine were utilized effectively for preserving and restoring neurocognitive function. Prior studies have shown that glutamate levels can increase during an infectious process. Glutamate is an excitatory neurotransmitter that is utilized by the organum vasculosum laminae terminalis through the neuronal excitatory system and causes an increase in body temperature which can lead to hyperpyrexia. Similar to neurogenic fevers, hyperpyrexia can lead to neurological decline and irreversible cognitive dysfunction. Inhibition of the glutamate aids a decrease in excitatory states, and improves the brain's regulatory mechanism, including temperature control. To further improve cognitive function, dopamine levels were increased with a dopamine agonist.

CONCLUSIONS

We propose that a combination of levetiracetam and amantadine may provide neuroprotective and neurorestorative properties when administered during a period of hyperpyrexia accompanied by any form of mental status changes, particularly if there is a decline in Glasgow Coma Score.

Changes in electroencephalographic characteristics and blood-brain barrier permeability in WAG/Rij rats with cortical dysplasia

PURPOSE

This study investigated the effects of cortical dysplasia (CD) on electrophysiology and blood-brain barrier (BBB) permeability in WAG/Rij rats with genetic absence epilepsy.

METHODS

Pregnant WAG/Rij rats were exposed to 145cGy of gamma-irradiation on embryonic day 17 to induce CD. An electroencephalogram was recorded from cortices subdurally in the offspring of the pregnant animals. Horseradish peroxidase (HRP) was used as determinant of BBB permeability.

RESULTS

A massive tissue loss in the cerebral cortex was seen in WAG/Rij rats with CD (p<0.05). There was a significant decrease in the number and duration of spike-and-wave discharges (SWDs) and an increase in the frequency of SWDs in the WAG/Rij rats with CD when compared with the properties of SWDs in intact WAG/Rij rats (p<0.01). Ultrastructurally, the accumulation of HRP reaction products in the cerebral cortex and thalamus of WAG/Rij rats was significantly higher than that of control values (p<0.01). The accumulation of HRP reaction products in the cerebral cortex and thalamus regions of WAG/Rij rats with CD increased and was higher than that of the control and WAG/Rij animals (p<0.01).

CONCLUSION

In our study, we showed that number and duration of SWDs decreased and SWD frequency increased in WAG/Rij rats with CD, suggesting a shift in seizure pattern. The association of these alterations with significant loss of cortical thickness and increased BBB permeability to HRP tracer may represent a causal relation of the EEG abnormalities with cerebral structural changes in these animals.

Neuroprotection and anti-seizure effects of levetiracetam in a rat model of penetrating ballistic-like brain injury

PURPOSE

We assessed the therapeutic efficacy of FDA-approved anti-epileptic drug Levetiracetam (LEV) to reduce post-traumatic nonconvulsive seizure (NCS) activity and promote neurobehavioral recovery following 10% frontal penetrating ballistic-like brain injury (PBBI) in male Sprague-Dawley rats.

METHODS

Experiment 1 anti-seizure study: 50 mg/kg LEV (25 mg/kg maintenance doses) was given twice daily for 3 days (LEV3D) following PBBI; outcome measures included seizures incidence, frequency, duration, and onset. Experiment 2 neuroprotection studies: 50 mg/kg LEV was given twice daily for either 3 (LEV3D) or 10 days (LEV10D) post-injury; outcome measures include motor (rotarod) and cognitive (water maze) functions.

RESULTS

LEV3D treatment attenuated seizure activity with significant reductions in NCS incidence (54%), frequency, duration, and delayed latency to seizure onset compared to vehicle treatment. LEV3D treatment failed to improve cognitive or motor performance; however extending the dosing regimen through 10 days post-injury afforded significant neuroprotective benefit. Animals treated with the extended LEV10D dosing regimen showed a twofold improvement in rotarod task latency to fall as well as significantly improved spatial learning performance (24%) in the MWM task.

CONCLUSIONS

These findings support the dual anti- seizure and neuroprotective role of LEV, but more importantly identify the importance of an extended dosing protocol which was specific to the therapeutic targets studied.

Water Exchange across the Blood-Brain Barrier in Obstructive Sleep Apnea: An MRI Diffusion-Weighted Pseudo-Continuous Arterial Spin Labeling Study

BACKGROUND AND PURPOSE

Obstructive sleep apnea (OSA) subjects show brain injury in sites that control autonomic, cognitive, and mood functions that are deficient in the condition. The processes contributing to injury may include altered blood-brain barrier (BBB) actions. Our aim was to examine BBB function, based on diffusion-weighted pseudo-continuous arterial spin labeling (DW-pCASL) procedures, in OSA compared to controls.

METHODS

We performed DW-pCASL imaging in nine OSA and nine controls on a 3.0-Tesla MRI scanner. Global mean gray and white matter arterial transient time (ATT, an index of large artery integrity), water exchange rate across the BBB (Kw, BBB function), DW-pCASL ratio, and cerebral blood flow (CBF) values were compared between OSA and control subjects.

RESULTS

Global mean gray and white matter ATT (OSA vs. controls; gray matter, 1.691 ± .120 vs. 1.658 ± .109 second, P = .49; white matter, 1.700 ± .115 vs. 1.650 ± .114 second, P = .44), and CBF values (gray matter, 57.4 ± 15.8 vs. 58.2 ± 10.7 ml/100 g/min, P = .67; white matter, 24.2 ± 7.0 vs. 24.6 ± 6.7 ml/100 g/min, P = .91) did not differ significantly, but global gray and white matter Kw (gray matter, 158.0 ± 28.9 vs. 220.8 ± 40.6 min(-1) , P = .002; white matter, 177.5 ± 57.2 vs. 261.1 ± 51.0 min(-1) , P = .006), and DW-pCASL ratio (gray matter, .727 ± .076 vs. .823 ± .069, P = .011; white matter, .722 ± .144 vs. .888 ± .100, P = .004) values were significantly reduced in OSA over controls.

CONCLUSIONS

OSA subjects show compromised BBB function, but intact large artery integrity. The BBB alterations may introduce neural damage contributing to abnormal functions in OSA, and suggest a need to repair BBB function with strategies commonly used in other fields.

The blood-brain barrier-gatekeeper to neuronal homeostasis: clinical implications in the setting of stroke

The blood-brain barrier is part of the neurovascular unit and serves as a functional and anatomical barrier between the blood and the extracellular space. It controls the flow of solutes in and out of the brain thereby providing an optimal environment for neuronal functioning. Paracellular transport between endothelial cells is restricted by tight junctions and transendothelial transport is reduced and more selective compared to capillaries of other organs. Further, the blood-brain barrier is involved in controlling blood flow and it is the site for signaling damage of the nervous system to the peripheral immune system. As an important player in brain homeostasis, blood-brain barrier dysfunction has been implicated in the pathophysiology of many brain diseases including stroke, traumatic brain injury, brain tumors, epilepsy and neurodegenerative disorders. In this article - highlighting recent advances in basic science - we review the features of the blood-brain barrier and their significance for neuronal homeostasis to discuss clinical implications for neurological complications following cerebral ischemia.

Additional antiepileptic mechanisms of levetiracetam in lithium-pilocarpine treated rats

Several studies have addressed the antiepileptic mechanisms of levetiracetam (LEV); however, its effect on catecholamines and the inflammatory mediators that play a role in epilepsy remain elusive. In the current work, lithium (Li) pretreated animals were administered LEV (500 mg/kg i.p) 30 min before the induction of convulsions by pilocarpine (PIL). Li-PIL-induced seizures were accompanied by increased levels of hippocampal prostaglandin (PG) E2, myeloperoxidase (MPO), tumor necrosis factor-α, and interleukin-10. Moreover, it markedly elevated hippocampal lipid peroxides and nitric oxide levels, while it inhibited the glutathione content. Li-PIL also reduced hippocampal noradrenaline, as well as dopamine contents. Pretreatment with LEV protected against Li-PIL-induced seizures, where it suppressed the severity and delayed the onset of seizures in Li-PIL treated rats. Moreover, LEV reduced PGE2 and MPO, yet it did not affect the level of both cytokines in the hippocampus. LEV also normalized hippocampal noradrenaline, dopamine, glutathione, lipid peroxides, and nitric oxide contents. In conclusion, alongside its antioxidant property, LEV anticonvulsive effect involves catecholamines restoration, as well as inhibition of PGE2, MPO, and nitric oxide.

Neurovascular unit in chronic pain

Chronic pain is a debilitating condition with major socioeconomic impact, whose neurobiological basis is still not clear. An involvement of the neurovascular unit (NVU) has been recently proposed. In particular, the blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB), two NVU key players, may be affected during the development of chronic pain; in particular, transient permeabilization of the barrier is suggested by several inflammatory- and nerve-injury-based pain models, and we argue that the clarification of molecular BBB/BSCB permeabilization events will shed new light in understanding chronic pain mechanisms. Possible biases in experiments supporting this theory and its translational potentials are discussed. Moving beyond an exclusive focus on the role of the endothelium, we propose that our understanding of the mechanisms subserving chronic pain will benefit from the extension of research efforts to the NVU as a whole. In this view, the available evidence on the interaction between analgesic drugs and the NVU is here reviewed. Chronic pain comorbidities, such as neuroinflammatory and neurodegenerative diseases, are also discussed in view of NVU changes, together with innovative pharmacological solutions targeting NVU components in chronic pain treatment.

Blood-brain barrier, epileptogenesis, and treatment strategies in cortical dysplasia

Cortical dysplasia (CD) is one of the most important causes of intractable epilepsy. The precise mechanisms of epileptogenesis in CD are not known. Using CD animal models, we attempted to understand the mechanisms and efficacy of various antiepileptic drugs. In two separate studies, we assessed (1) the effects of levetiracetam (LEV) and vagus nerve stimulation (VNS) on pentylenetetrazol (PTZ)-kindled rats, and (2) the effects of LEV and topiramate (TPM) on rats with CD and hyperthermia (HT). In the HT-induced rats with CD study, LEV and TPM decreased both the intensity of seizures and the number of rats with seizure. In these studies, we used immunocytochemistry (occludin, glial fibrillary acidic protein [GFAP], and P-glycoprotein [Pgp antibodies] and electron microscopy (EM) (sodium fluorescein [NaFlu]) and horseradish peroxidase [HRP]) to assess blood-brain barrier (BBB) integrity. Both LEV and TPM protected BBB. In PTZ- kindled rats with CD, both LEV and VNS reduced the duration of seizures. Immunocytochemistry and EM revealed no BBB impairment in any of the treatment groups. In a second set of experiments, we assessed the relationship between disruption of vascular components and epileptogenesis. Astrocytic albumin uptake in focal epileptogenic lesions with vascular components suggested that dysfunction of the BBB contributes immediately to epileptogenesis, rather than simply resulting from seizure activity. Hemosiderin deposits were seen as potential epileptogenic triggers in vascular malformations (e.g., cavernomas [CA] or arteriovenous malformations [AVMs] with or without a dysplastic cortical component). However, we found strikingly high accumulation of astrocytic albumin deposits in surgically removed brain parenchyma in the vicinity of CAs and AVMs from patients with pharmacoresistant epilepsy, which suggests different pathophysiologic dispersion pathways for hemosiderin and albumin in vascular lesions.