Cytokines and epilepsy

Impact of mood stabilizers and antiepileptic drugs on cytokine production in-vitro

Changes within the immune system have been reported to contribute to the pathophysiology of bipolar disorder and epilepsy. Interestingly, overlapping results regarding the cytokine system have been found for both diseases, namely alterations of interleukins IL-1β, IL-2, IL-4, IL-6, and tumor necrosis factor-α (TNF-α). However, the effect of mood stabilizers and antiepileptic drugs (AEDs) on these cytokines has not been systematically evaluated, and their effect on IL-17 and IL-22, other immunologically important cytokines, has not been reported. Therefore, we systematically measured levels of IL-1β, IL-2, IL-4, IL-6, IL-17, IL-22 and TNF-α in stimulated blood of 14 healthy female subjects in a whole blood assay using the toxic shock syndrome toxin TSST-1 as stimulant. Blood was supplemented with the mood stabilizers or antiepileptic drugs primidone (PRM), carbamazepine (CBZ), levetiracetam (LEV), lamotrigine (LTG), valproic acid (VPA), oxcarbazepine (OXC), topiramate (TPM), phenobarbital (PB), lithium, or no drug. IL-1β production was significantly decreased by PRM, CBZ, LEV, LTG, OXC, PB and lithium. IL-2 significantly decreased by PRM, CBZ, LEV, LTG, VPA, OXC, TPM and PB. IL-22 significantly increased by PRM, CBZ, LEV, OXC, TPM and lithium and decreased by VPA. TNF-α production significantly decreased under all applied drugs. The mechanism of action and side effects of mood stabilizers and AEDs may involve modulation of IL-1β, IL-2, IL-22 and TNF-α signaling pathways. IL-22 may be a research target for specific therapeutic effects of mood stabilizers and AEDs. These drugs might influence cytokine production by modulating ion channels and γ-aminobutyric acid (GABA) receptors of immune cells.

Increased metalloprotease activity in the epileptogenic lesion--Lobectomy reduces metalloprotease activity and urokinase-type uPAR circulating levels

Inflammation influences the pathogenesis of seizures by boosting neuronal degeneration of temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). This work aimed to determine the activity of metalloproteases (MMPs) in brain tissue fragments of TLE-HS patients and the effect of lobectomy on circulating inflammatory biomarkers. Surgical fragments (n=4) from epileptogenic focus (EF) e perilesion area (PL), and control hippocampus from autopsy (n=5) were processed for glial protein (GFAP), activated microglia (IB4) immunohistochemistry, and metalloprotease activity (MMP-2, -9). Perilesional area showed GFAP positive cells with morphology of activate astrocyte and reactive gliosis nearby the lesion. In the lesion foci, astrocytes had altered cytoarchitecture with disorganized stroma suggestive of necrosis, and numerous mononuclear cells with few projections and morphological characteristics of activate microglia. Analysis of MMP-9 and MMP-2 in the sera before and after hippocampectomy confirmed the inflammatory pattern of TLE-HS, with high MMP-9 activity; high MMP-9/TIMP-1 and urokinase uPAR plasma levels before lobectomy but low after surgery. Maintenance of MMP-2 activity indicates persistent tissue remodeling in both groups. The present work shows that patients with chronic and medically intractable TLE-HS that undergone amigdalo-hippocampectomy for removal of epileptogenic lesion had a clinical enduring benefit of lack seizure recurrence for up to a year, and consistent reduction of proteases (MMP-9 and uPAR) activation that participate as important inflammatory epileptogenic inducers.

Anticonvulsant activity of bone marrow cells in electroconvulsive seizures in mice

Background

Bone marrow is an accessible source of progenitor cells, which have been investigated as treatment for neurological diseases in a number of clinical trials. Here we evaluated the potential benefit of bone marrow cells in protecting against convulsive seizures induced by maximum electroconvulsive shock (MES), a widely used model for screening of anti-epileptic drugs. Behavioral and inflammatory responses were measured after MES induction in order to verify the effects promoted by transplantation of bone marrow cells. To assess the anticonvulsant effects of bone marrow cell transplantation, we measured the frequency and duration of tonic seizure, the mortality rate, the microglial expression and the blood levels of cytokine IL-1, IL-6, IL-10 and TNF-α after MES induction. We hypothesized that these behavioral and inflammatory responses to a strong stimulus such as a convulsive seizure could be modified by the transplantation of bone marrow cells.

Results

Bone marrow transplanted cells altered the convulsive threshold and showed anticonvulsant effect by protecting from tonic seizures. Bone marrow cells modified the microglial expression in the analyzed brain areas, increased the IL-10 and attenuate IL-6 levels.

Conclusions

Bone marrow cells exert protective effects by blocking the course of electroconvulsive seizures. Additionally, electroconvulsive seizures induced acute inflammatory responses by altering the pattern of microglia expression, as well as in IL-6 and IL-10 levels. Our findings also indicated that the anticonvulsant effects of these cells can be tested with the MES model following the same paradigm used for drug testing in pharmacological screening. Studies on the inflammatory reaction in response to acute seizures in the presence of transplanted bone marrow cells might open a wide range of discussions on the mechanisms relevant to the pathophysiology of epilepsies.

Outcome predictors for status epilepticus--what really counts

In adult patients with status epilepticus (SE)-a life-threatening state of ongoing or repetitive seizures--the current evidence regarding outcome prediction is based on clinical, biochemical and EEG determinants. These predictors of outcome involve clinical features such as age, history of prior seizures or epilepsy, SE aetiology, level of consciousness, and seizure type at SE onset. The clinical risk-benefit calculation between the danger of undertreated persistent seizure activity and, conversely, the potential damage from unwarranted aggressive treatments remains a constant challenge. Improved knowledge of outcome determinants, as well as increased availability of reliable outcome prediction models early in the course of SE, is paramount for optimization of treatment of patients who develop this disorder. In this Review, we discuss the major prognostic determinants of outcome in SE. Through consideration of studies that provide measures of association between predictors of SE outcome and death, we propose a detailed--but as yet unvalidated--paradigm for assessment of these predictors during the course of SE. Such an algorithm could guide the organization of results from existing trials and provide direction with regard to the parameters that should be monitored in future studies of SE.

Maternal immune activation promotes hippocampal kindling epileptogenesis in mice

OBJECTIVE

Maternal immune activation (MIA) triggered by infections has been identified as a cause of autism in offspring. Considering the involvement of perturbations in innate immunity in epilepsy, we examined whether MIA represents a risk factor for epilepsy as well. The role of specific MIA components interleukin (IL)-6 and IL-1β was also addressed.

METHODS

MIA was induced in C57BL/6 mice by polyinosinic-polycytidylic acid (PIC) injected during embryonic days 12 to 16. Beginning from postnatal day 40, the propensity of the offspring to epilepsy was examined using hippocampal kindling; autismlike behavior was studied using the sociability test. The involvement of IL-6 and IL-1β in PIC-induced effects was studied by the coadministration of the cytokine antibodies with PIC, and by delivering recombinant cytokines in lieu of PIC.

RESULTS

The offspring of PIC-exposed mice exhibited increased hippocampal excitability, accelerated kindling rate, prolonged increase of seizure susceptibility after kindling, and diminished sociability. Epileptic impairments were abolished by antibodies to IL-6 or IL-1β. Neither of the recombinant cytokines alone increased the propensity to seizures; however, when combined, they produced effects similar to those induced by PIC. PIC-induced behavioral deficits were abolished by IL-6 antibodies and were mimicked by recombinant IL-6; IL-1β was not involved.

INTERPRETATION

In addition to confirming the previously established critical role of IL-6 in the development of autismlike behavior following MIA, the present study shows that concurrent involvement of IL-6 and IL-1β is required for priming the offspring for epilepsy. These data shed light on mechanisms of comorbidity between autism and epilepsy.

The role of cytokines in seizures: interleukin (IL)-1β, IL-1Ra, IL-8, and IL-10

Brain insults, including neurotrauma, infection, and perinatal injuries such as hypoxic ischemic encephalopathy, generate inflammation in the brain. These inflammatory cascades induce a wide spectrum of cytokines, which can cause neuron degeneration, have neurotoxic effects on brain tissue, and lead to the development of seizures, even if they are subclinical and occur at birth. Cytokines are secreted by the glial cells of the central nervous system and they function as immune system mediators. Cytokines can be proinflammatory or anti-inflammatory. Interleukin (IL)-1β and IL-8 are proinflammatory cytokines that activate additional cytokine cascades and increase seizure susceptibility and organ damage, whereas IL-1 receptor antagonist and IL-10 act as anti-inflammatory cytokines that have protective and anticonvulsant effects. Therefore, the immune system and its associated inflammatory reactions appear to play an important role in brain damage. Whether cytokine release is relevant for the processes of epileptogenesis and antiepileptogenesis, and whether epileptogenesis could be prevented by immunomodulatory treatment should be addressed in future clinical studies. Furthermore, early detection of brain damage and early intervention are essential for the prevention of disease progression and further neurological complications. Therefore, cytokines might be useful as biomarkers for earlier detection of brain damage in high-risk infants.

Modulation of Immunity and the Inflammatory Response: A New Target for Treating Drug-resistant Epilepsy

Until recently, epilepsy medical therapy is usually limited to anti-epileptic drugs (AEDs). However, approximately 1/3 of epilepsy patients, described as drug-resistant epilepsy (DRE) patients, still suffer from continuous frequent seizures despite receiving adequate AEDs treatment of sufficient duration. More recently, with the remarkable progress of immunology, immunity and inflammation are considered to be key elements of the pathobiology of epilepsy. Activation of inflammatory processes in brain tissue has been observed in both experimental seizure animal models and epilepsy patients. Anti-inflammatory and immunotherapies also showed significant anticonvulsant properties both in clinical and in experimental settings. The above emerging evidence indicates that modulation of immunity and inflammatory processes could serve as novel specific targets to achieve potential anticonvulsant effects for the patients with epilepsy, especially DRE. Herein we review the recent evidence supporting the role of inflammation in the development and perpetuation of seizures, and also discuss the recent achievements in modulation of inflammation and immunotherapy applied to the treatment of epilepsy. Apart from medical therapy, we also discuss the influences of surgery, ketogenic diet, and electroconvulsive therapy on immunity and inflammation in DRE patients. Taken together, a promising perspective is suggested for future immunomodulatory therapies in the treatment of patients with DRE.

Hippocampal gene expression dysregulation of Klotho, nuclear factor kappa B and tumor necrosis factor in temporal lobe epilepsy patients

Background

Previous research in animal seizure models indicates that the pleiotropic cytokine TNF is an important effector/mediator of neuroinflammation and cell death. Recently, it has been demonstrated that TNF downregulates Klotho (KL) through the nuclear factor kappa B (NFkB) system in animal models of chronic kidney disease and colitis. KL function in the brain is unclear, although Klotho knockout (Kl^−/−) mice exhibit neural degeneration and a reduction of hippocampal synapses. Our aim was to verify if the triad KL-NFKB1-TNF is also dysregulated in temporal lobe epilepsy associated with hippocampal sclerosis (TLE(HS)) patients.

Findings

We evaluated TNF, NFKB1 and KL relative mRNA expression levels by reverse transcription quantitative PCR (RT-qPCR) in resected hippocampal tissue samples from 14 TLE(HS) patients and compared them to five post mortem controls. Four reference genes were used: GAPDH, HPRT1, ENO2 and TBP. We found that TNF expression was dramatically upregulated in TLE(HS) patients (P <0.005). NFKB1 expression was also increased (P <0.03) while KL was significantly downregulated (P <0.03) in TLE(HS) patients. Hippocampal KL expression had an inverse correlation with NFKB1 and TNF.

Conclusions

Our data suggest that, similar to other inflammatory diseases, TNF downregulates KL through NFkB in TLE(HS) patients. The remarkable TNF upregulation in patients is a strong indication of hippocampal chronic inflammation. Our finding of hippocampal KL downregulation has wide implications not only for TLE(HS) but also for other neuronal disorders related to neurodegeneration associated with inflammation.

Blood levels of cytokines in children with idiopathic partial and generalized epilepsy

PURPOSE

Antiepileptic drugs have been reported to reduce the levels of serum immunoglobulins and affect the production and levels of certain cytokines. We investigated the effects of valproic acid (VPA) and topiramate (TPM) on the blood levels of interleukin (IL)-1α, IL-1β, IL-6, IL-10, and TNF-α in children with idiopathic generalized and partial epilepsy.

METHODS

Forty prepubertal children aged 6-12 (mean 8.3±1.7) years, 19/40 (47.5%) female and 21/40 (52.5%) male, with idiopathic generalized or partial epilepsy diagnosed in the child neurology outpatient clinic were included. The patients were divided into two treatment groups: 20 were treated with VPA and 20 with TPM. The plasma levels of IL-1α, IL-1β, IL-6, IL-10, TNF-α were measured using ELISA method before the initiation of treatment and at the 6th and 12th months of the treatment. The Chi-square test was used to compare qualitative data. To compare the periods, recurrence measurements were done using variance analysis and Freidman 2-sided variance analysis. p<0.05 was considered as statistically significant.

RESULTS

In the VPA group, the levels of IL-1α significantly increased at 12 months while the levels of IL-10 decreased at 6 months of treatment compared to values before treatment (p<0.05). There was no significant difference in levels of IL-1β, IL-6, TNF-α (p>0.05). In the TPM group, lower levels of IL-10 were observed at 6th and 12th months compared to the onset of treatment (p<0.05).

CONCLUSION

The results of this study demonstrated that VPA and TPM might lead to changes in the levels of cytokines in epileptic patients. The next step would be to investigate the relation of these findings to the outcome of epilepsy and response to treatment.

Vagus nerve stimulation to augment recovery from severe traumatic brain injury impeding consciousness: a prospective pilot clinical trial

OBJECTIVES

Traumatic brain injury (TBI) has high morbidity and mortality in both civilian and military populations. Blast and other mechanisms of TBI damage the brain by causing neurons to disconnect and atrophy. Such traumatic axonal injury can lead to persistent vegetative and minimally conscious states (VS and MCS), for which limited treatment options exist, including physical, occupational, speech, and cognitive therapies. More than 60 000 patients have received vagus nerve stimulation (VNS) for epilepsy and depression. In addition to decreased seizure frequency and severity, patients report enhanced mood, reduced daytime sleepiness independent of seizure control, increased slow wave sleep, and improved cognition, memory, and quality of life. Early stimulation of the vagus nerve accelerates the rate and extent of behavioral and cognitive recovery after fluid percussion brain injury in rats.

METHODS

We recently obtained Food and Drug Administration (FDA) approval for a pilot prospective randomized crossover trial to demonstrate objective improvement in clinical outcome by placement of a vagus nerve stimulator in patients who are recovering from severe TBI. Our hypothesis is that stimulation of the vagus nerve results in increased cerebral blood flow and metabolism in the forebrain, thalamus, and reticular formation, which promotes arousal and improved consciousness, thereby improving outcome after TBI resulting in MCS or VS.

DISCUSSION

If this study demonstrates that VNS can safely and positively impact outcome, then a larger randomized prospective crossover trial will be proposed.

The interleukin 17 system in cortical lesions in focal cortical dysplasias

Focal cortical dysplasias (FCDs) are increasingly recognized as important causes of medically intractable epilepsy. To understand the potential role of the interleukin 17 (IL-17) system in the epileptogenesis of FCDs, we studied the expression patterns of the IL-17 system in 15 FCD type Ia (FCDIa), 12 FCD type IIa (FCDIIa), and 12 FCD type IIb (FCDIIb) cortical lesions and compared the results with those in cerebral cortex from 10 control patients. Protein levels of IL-17, IL-17 receptor (IL-17R), and downstream factors of the IL-17 pathway (nuclear factor-κB activator 1 [NFκB; ACT1] and NFκB-p65) were markedly elevated in FCDIa, FCDIIa, and FCDIIb. Moreover, protein levels of IL-17 and IL-17R positively correlated with the frequency of seizures in FCD patients. Immunostaining indicated that IL-17 and IL-17R are highly expressed in neuronal microcolumns, dysmorphic neurons, balloon cells, astrocytes, and vascular endothelial cells. Nuclear factor-κB activator 1 and NFκB-p65 were diffusely expressed in FCDs. In addition, we detected a few IL-17-positive, CD4-positive T lymphocytes in FCDIIa and FCDIIb but not in FCDIa. Taken together, these findings suggest that the overexpression of the IL-17 system and the activation of the IL-17 signal transduction pathway may be involved in the epileptogenicity of cortical lesions in FCDs, thus representing a novel potential target for antiepileptic therapy.

MRI changes and complement activation correlate with epileptogenicity in a mouse model of temporal lobe epilepsy

The complex pathogenesis of temporal lobe epilepsy includes neuronal and glial pathology, synaptic reorganization, and an immune response. However, the spatio-temporal pattern of structural changes in the brain that provide a substrate for seizure generation and modulate the seizure phenotype is yet to be completely elucidated. We used quantitative magnetic resonance imaging (MRI) to study structural changes triggered by status epilepticus (SE) and their association with epileptogenesis and with activation of complement component 3 (C3). SE was induced by injection of pilocarpine in CD1 mice. Quantitative diffusion-weighted imaging and T2 relaxometry was performed using a 16.4-Tesla MRI scanner at 3 h and 1, 2, 7, 14, 28, 35, and 49 days post-SE. Following longitudinal MRI examinations, spontaneous recurrent seizures and interictal spikes were quantified using continuous video-EEG monitoring. Immunohistochemical analysis of C3 expression was performed at 48 h, 7 days, and 4 months post-SE. MRI changes were dynamic, reflecting different outcomes in relation to the development of epilepsy. Apparent diffusion coefficient changes in the hippocampus at 7 days post-SE correlated with the severity of the evolving epilepsy. C3 activation was found in all stages of epileptogenesis within the areas with significant MRI changes and correlated with the severity of epileptic condition.

Role of IL-6 in the etiology of hyperexcitable neuropsychiatric conditions: experimental evidence and therapeutic implications

Many neuropsychiatric conditions are primed or triggered by different types of stressors. The mechanisms through which stress induces neuropsychiatric disease are complex and incompletely understood. A ‘double hit’ hypothesis of neuropsychiatric disease postulates that stress induces maladaptive behavior in two phases separated by a dormant period. Recent research shows that the pleiotropic cytokine IL-6 is released centrally and peripherally following physical and psychological stress. In this article, we analyze evidence from clinics and animal models suggesting that stress-induced elevation in the levels of IL-6 may play a key role in the etiology of a heterogeneous family of hyperexcitable central conditions including epilepsy, schizophrenic psychoses, anxiety and disorders of the autistic spectrum. The cellular mechanism leading to hyperexcitable conditions might be a decrease in inhibitory/excitatory synaptic balance in either or both temporal phases of the conditions. Following these observations, we discuss how they may have important implications for optimal prophylactic and therapeutic pharmacological treatment.

Epileptic seizures in Japanese patients with multiple sclerosis and neuromyelitis optica

PURPOSE

To examine the incidence and clinical features of epileptic seizures in Japanese patients with multiple sclerosis (MS) and neuromyelitis optica (NMO).

METHODS

We reviewed medical records of all patients who visited the Neurology Clinic in Utano National Hospital between January and December, 2009, and enrolled 63 MS patients who fulfilled the McDonald criteria (2005) (mean age, 41.1 years) and 31 NMO patients who fulfilled the Wingerchuk criteria (2006) (mean age, 44.6 years). Patients with a history of epileptic seizures were selected and their clinical features were obtained.

RESULTS

Four MS patients (6.3%; 2 men and 2 women; mean age, 32.5 years) and 4 NMO patients (12.9%; 4 women; mean age, 36.0 years) had epileptic seizures. Disease onset age of MS patients with seizures was significantly younger than those without seizures by 13.1 years, and Expanded Disability Status Scale of NMO patient with seizures was significantly higher than those without seizures by 2.2. All 8 patients showed brain lesions on magnetic resonance imaging and 2 MS patients had tumefactive demyelinating lesions. Electroencephalography showed interictal epileptiform discharges in 5 patients. Seizure types of 6 patients were recognized as partial seizures based on clinical semiology. All patients responded to antiepileptic therapy well. In both MS and NMO, there were both seizures with and without concurrent relapse.

CONCLUSIONS

Similar to MS, NMO patients possibly have higher risk to develop epileptic seizures than general population.

Cell volume regulation modulates NLRP3 inflammasome activation

Cell volume regulation is a primitive response to alterations in environmental osmolarity. The NLRP3 inflammasome is a multiprotein complex that senses pathogen- and danger-associated signals. Here, we report that, from fish to mammals, the basic mechanisms of cell swelling and regulatory volume decrease (RVD) are sensed via the NLRP3 inflammasome. We found that a decrease in extracellular osmolarity induced a K(+)-dependent conformational change of the preassembled NLRP3-inactive inflammasome during cell swelling, followed by activation of the NLRP3 inflammasome and caspase-1, which was controlled by transient receptor potential channels during RVD. Both mechanisms were necessary for interleukin-1β processing. Increased extracellular osmolarity prevented caspase-1 activation by different known NLRP3 activators. Collectively, our data identify cell volume regulation as a basic conserved homeostatic mechanism associated with the formation of the NLRP3 inflammasome and reveal a mechanism for NLRP3 inflammasome activation.

Protein expression profiling of inflammatory mediators in human temporal lobe epilepsy reveals co-activation of multiple chemokines and cytokines

Mesial temporal lobe epilepsy (mTLE) is a chronic and often treatment-refractory brain disorder characterized by recurrent seizures originating from the hippocampus. The pathogenic mechanisms underlying mTLE remain largely unknown. Recent clinical and experimental evidence supports a role of various inflammatory mediators in mTLE. Here, we performed protein expression profiling of 40 inflammatory mediators in surgical resection material from mTLE patients with and without hippocampal sclerosis, and autopsy controls using a multiplex bead-based immunoassay. In mTLE patients we identified 21 upregulated inflammatory mediators, including 10 cytokines and 7 chemokines. Many of these upregulated mediators have not previously been implicated in mTLE (for example, CCL22, IL-7 and IL-25). Comparing the three patient groups, two main hippocampal expression patterns could be distinguished, pattern I (for example, IL-10 and IL-25) showing increased expression in mTLE + HS patients compared to mTLE-HS and controls, and pattern II (for example, CCL4 and IL-7) showing increased expression in both mTLE groups compared to controls. Upregulation of a subset of inflammatory mediators (for example, IL-25 and IL-7) could not only be detected in the hippocampus of mTLE patients, but also in the neocortex. Principle component analysis was used to cluster the inflammatory mediators into several components. Follow-up analyses of the identified components revealed that the three patient groups could be discriminated based on their unique expression profiles. Immunocytochemistry showed that IL-25 IR (pattern I) and CCL4 IR (pattern II) were localized in astrocytes and microglia, whereas IL-25 IR was also detected in neurons. Our data shows co-activation of multiple inflammatory mediators in hippocampus and neocortex of mTLE patients, indicating activation of multiple pro- and anti-epileptogenic immune pathways in this disease.

Altered synaptic transmission in the hippocampus of transgenic mice with enhanced central nervous systems expression of interleukin-6

Elevated levels of the inflammatory cytokine interleukin-6 (IL-6) occur in a number of CNS disorders. However, little is known about how this condition affects CNS neuronal function. Transgenic mice that express elevated levels of IL-6 in the CNS show cognitive changes, increased propensity for hippocampal seizures and reduced number of inhibitory interneurons, suggesting that elevated levels of IL-6 can cause neuroadaptive changes that alter hippocampal function. To identify these neuroadaptive changes, we measured the levels of protein expression using Western blot analysis and synaptic function using field potential recordings in hippocampus from IL-6 transgenic mice (IL-6 tg) and their non-transgenic (non-tg) littermates. Western blot analysis showed enhanced levels of the GFAP and STAT3 in the IL-6 tg hippocampus compared with the non-tg hippocampus, but no difference for several other proteins. Field potential recordings of synaptic transmission at the Schaffer collateral to CA1 synapse showed enhanced dendritic excitatory postsynaptic potentials and somatic population spikes in the CA1 region of hippocampal slices from IL-6 tg mice compared with slices from non-tg littermate controls. No differences were observed for several forms of short-term and long-term synaptic plasticity between hippocampal slices from IL-6 tg and non-tg mice. These results demonstrate that elevated levels of IL-6 can alter mechanisms involved in the excitability of hippocampal neurons and synapses, an effect consistent with recent evidence indicating that elevated production of IL-6 plays an important role in conditions associated with seizure activity and in other impairments observed in CNS disorders with a neuroinflammatory component.

TNF-overexpression in Borna disease virus-infected mouse brains triggers inflammatory reaction and epileptic seizures

Proinflammatory state of the brain increases the risk for seizure development. Neonatal Borna disease virus (BDV)-infection of mice with neuronal overexpression of tumor necrosis factor-α (TNF) was used to investigate the complex relationship between enhanced cytokine levels, neurotropic virus infection and reaction pattern of brain cells focusing on its role for seizure induction. Viral antigen and glial markers were visualized by immunohistochemistry. Different levels of TNF in the CNS were provided by the use of heterozygous and homozygous TNF overexpressing mice. Transgenic TNF, total TNF (native and transgenic), TNF-receptor (TNFR1, TNFR2), IL-1 and N-methyl-D-aspartate (NMDA)-receptor subunit 2B (NR2B) mRNA values were measured by real time RT-PCR. BDV-infection of TNF-transgenic mice resulted in non-purulent meningoencephalitis accompanied by epileptic seizures with a higher frequency in homozygous animals. This correlated with lower weight gain, stronger degree and progression of encephalitis and early, strong microglia activation in the TNF-transgenic mice, most obviously in homozygous animals. Activation of astroglia could be more intense and associated with an unusual hypertrophy in the transgenic mice. BDV-antigen distribution and infectivity in the CNS was comparable in TNF-transgenic and wild-type animals. Transgenic TNF mRNA-expression was restricted to forebrain regions as the transgene construct comprised the promoter of NMDA-receptor subunit2B and induced up-regulation of native TNF mRNA. Total TNF mRNA levels did not increase significantly after BDV-infection in the brain of transgenic mice but TNFR1, TNFR2 and IL-1 mRNA values, mainly in the TNF overexpressing brain areas. NR2B mRNA levels were not influenced by transgene expression or BDV-infection. Neuronal TNF-overexpression combined with BDV-infection leads to cytokine up-regulation, CNS inflammation and glial cell activation and confirmed the presensitizing effect of elevated cytokine levels for the development of spontaneous epileptic seizures when exposed to additional infectious noxi.

Do gene polymorphism in IL-1β, TNF-α and IL-6 influence therapeutic response in patients with drug refractory epilepsy?

PURPOSE

Pro-inflammatory cytokines may play an important pathophysiological role in patients with epilepsy. To understand the role of genes encoding pro-inflammatory cytokines in epilepsy, this study aimed to evaluate the polymorphisms of the promoter regions of IL-1β-511C>T (rs16944), TNF-α-308G>A (rs1800629) and IL-6-174G>C (rs1800795) genes and to look into the interaction between these genes in influencing seizure susceptibility, seizure frequency and response to therapy.

METHODS

The comparative frequency of polymorphism was determined in rs16944, rs1800629 and rs1800795 using PCR-RFLP in a group of 120 persons with epilepsy (PWE) and 110 ethnically matched healthy subjects of comparable age and sex in the North Indian population.

RESULTS

Alleles and genotypes of rs16944, rs1800629 and rs1800795 were not found to influence the odds ratio of having susceptibility to epilepsy. Also gene-gene interaction of possible nine combinations of these genes did not show any positive association with epilepsy. The genotype and allelic frequency of rs1800795 showed a significant association (p<0.05) in seizure frequency (number of seizures/6-months) and drug refractory epilepsy. However, the genotype and allelic frequency of rs16944 and rs1800629 were not found to have such effect.

CONCLUSION

This study demonstrates that the rs16944, rs1800629 and rs1800795 polymorphism does not act as a strong susceptibility factor for epilepsy in North Indian population. The genotypic association of rs1800795 with seizure frequency and drug-refractory epilepsy raises the issue that a specific set of polymorphic genes can influence seizures and therapeutic response in epilepsy.

Atypical febrile seizures, mesial temporal lobe epilepsy, and dual pathology

Febrile seizures occurring in the neonatal period, especially when prolonged, are thought to be involved in the later development of mesial temporal lobe epilepsy (mTLE) in children. The presence of an often undetected, underlying cortical malformation has also been reported to be implicated in the epileptogenesis process following febrile seizures. This paper highlights some of the various animal models of febrile seizures and of cortical malformation and portrays a two-hit model that efficiently mimics these two insults and leads to spontaneous recurrent seizures in adult rats. Potential mechanisms are further proposed to explain how these two insults may each, or together, contribute to network hyperexcitability and epileptogenesis. Finally the clinical relevance of the two-hit model is briefly discussed in light of a therapeutic and preventive approach to mTLE.

Acute phase proteins and white blood cell levels for prediction of infectious complications in status epilepticus

Introduction

Infections in status epilepticus (SE) patients result in severe morbidity making early diagnosis crucial. As SE may lead to inflammatory reaction, the value of acute phase proteins and white blood cells (WBC) for diagnosis of infections during SE may be important. We examined the reliability of C-reactive protein (CRP), procalcitonin (PCT), and WBC for diagnosis of infections during SE.

Methods

All consecutive SE patients treated in the ICU from 2005 to 2009 were included. Clinical and microbiological records, and measurements of CRP and WBC during SE were analyzed. Subgroup analysis was performed for additional PCT measurements in the first 48 hours of SE.

Results

A total of 22.5% of 160 consecutive SE patients had infections during SE. Single levels of CRP and WBC had no association with the presence of infections. Their linear changes over the first three days after SE onset were significantly associated with the presence of infections (P = 0.0012 for CRP, P = 0.0137 for WBC). Levels of PCT were available for 31 patients and did not differ significantly in patients with and without infections. Sensitivity of PCT and CRP was high (94% and 83%) and the negative predictive value of CRP increased over the first three days to 97%. Specificity was low, without improvement for different cut-offs.

Conclusions

Single levels of CRP and WBC are not reliable for diagnosis of infections during SE, while their linear changes over time significantly correlate with the presence of infections. In addition, low levels of CRP and PCT rule out hospital-acquired infections in SE patients.

Early molecular and synaptic dysfunctions in the prodromal stages of Alzheimer’s disease: focus on TNF-α and IL-1β

Alterations in cytokine expression as well as deficits in synaptic activity are two features observed in early, prodromal stages of Alzheimer’s disease (AD). The cytokines TNF-α and IL-1β are not only mediators of immune responses, but are also involved in regulating synaptic activity through their effects on neuronal excitability and Hebbian plasticity. We propose that early changes occurring in the AD brain, such as increases in soluble amyloid-β oligomers, may increase the expression of certain cytokines and subsequently cause alterations in cytokine-mediated synaptic activity. A shift of focus towards the prodromal stages of AD, which incorporate the earliest detectable molecular, electrophysiological and behavioral alterations, may provide novel therapeutic targets and potential biomarkers for this currently incurable neurodegenerative disease.

Strong anticonvulsant effect of thalidomide on amygdaloid kindling

Thalidomide was synthesized more than 50 years ago as hypnotic sedative with unique pharmacologic properties. Recently, we have described a notorious anticonvulsant effect of thalidomide on pentylenetetrazole-induced seizures. Here, we report the results of thalidomide administration on amygdaloid kindling. A total of 100 male Wistar rats were implanted with brain electrodes in the basolateral amygdaloid nucleus and the sensory motor cortex. After surgery the animals received a daily electric stimulus through the amygdaline electrode (500 μA intensity, 60 Hz frequency, 1 ms duration) until seizures appeared. The following treatment groups were made: (a) controls; (b) rats treated daily with thalidomide (10 mg/kg) or with topiramate (80 mg/kg); (c) rats treated with different doses of thalidomide. Significant reduction in the after-discharge and retard of behavioral stages were observed in rats treated with thalidomide or with topiramate as compared with controls (p<0.01): Also, a similar anticonvulsant outcome of thalidomide therapy was obtained with doses of either 2.5, 5, 10 or 50 mg/kg; at 100 mg/kg all epileptic activity was suppressed. Anticonvulsant efficacy of thalidomide was superior in most parameters than that obtained with topiramate. In amygdaloid kindling, which simulates human epilepsy characterized by focal seizures secondarily generalized, low doses of thalidomide display strong anticonvulsant properties.