Proinflammatory cytokines, prostaglandins and zinc in febrile convulsions

Alterations in Rat Hippocampal Glutamatergic System Properties after Prolonged Febrile Seizures

Febrile seizures during early childhood may result in central nervous system developmental disorders. However, the specific mechanisms behind the impact of febrile seizures on the developing brain are not well understood. To address this gap in knowledge, we employed a hyperthermic model of febrile seizures in 10-day-old rats and tracked their development over two months. Our objective was to determine the degree to which the properties of the hippocampal glutamatergic system are modified. We analyzed whether pyramidal glutamatergic neurons in the hippocampus die after febrile seizures. Our findings indicate that there is a reduction in the number of neurons in various regions of the hippocampus in the first two days after seizures. The CA1 field showed the greatest susceptibility, and the reduction in the number of neurons in post-FS rats in this area appeared to be long-lasting. Electrophysiological studies indicate that febrile seizures cause a reduction in glutamatergic transmission, leading to decreased local field potential amplitude. This impairment could be attributable to diminished glutamate release probability as evidenced by decreases in the frequency of miniature excitatory postsynaptic currents and increases in the paired-pulse ratio of synaptic responses. We also found higher threshold current causing hind limb extension in the maximal electroshock seizure threshold test of rats 2 months after febrile seizures compared to the control animals. Our research suggests that febrile seizures can impair glutamatergic transmission, which may protect against future seizures.

Neutrophil-lymphocyte ratio, red cell distribution width and mean platelet volume as practical markers in febrile seizure classification

OBJECTIVE

To examine the neutrophil-lymphocyte ratio, red cell distribution width and mean platelet volume in patients with febrile seizure and to determine their role in febrile seizure classification.

METHODS

This was a retrospective hospital-based study conducted among patients aged 5 to 72 months admitted with febrile seizure. Children who had febrile seizures due to upper respiratory tract infection were included in the study. The children were divided into two groups: simple febrile seizures and complex febrile seizures. Patients with a history of febrile status epilepticus, previous convulsions, use of antiepileptic or other chronic drugs, foci of infection other than the upper respiratory tract infection, abnormal biochemical parameters, and chronic mental or physical disease were excluded from the study. Clinical and laboratory findings of the patients were obtained from digital medical records.

RESULTS

The records of 112 febrile seizure patients were reviewed, and 89 were grouped as simple and 23 as complex febrile seizures. Although there was no statistically significant difference between the two groups in terms of the mean red cell distribution width values (p=0.703), neutrophil-lymphocyte ratio and mean platelet volume were significantly higher in patients with complex febrile seizures (p=0.034, p=0.037; respectively).

CONCLUSIONS

This study showed that neutrophil-lymphocyte ratio and mean platelet volume could be practical and inexpensive clinical markers for febrile seizure classification. A similar result could not be reached for red cell distribution width in this study. These findings should be supported by multicenter studies with large samples.

Exploring the Involvement of Cytokines in Pediatric Patients Afflicted by Simple Febrile Seizures: A Case-Control Study

AIM

Most children under six with seizures experience febrile seizures (FS), which occur with a temperature of 38°C or higher and no apparent infectious or metabolic causes. FS has a multifaceted etiology, involving genetic and environmental factors. This study aimed to explore the connection between the cytokine system (part of the immune system related to inflammation) and FS to uncover potential relationships.

METHOD

This research was carried out on 50 patients experiencing FS and 25 patients experiencing only fever served as cases and controls, respectively. The patient's blood was obtained under sterile circumstances from the antecubital/femoral vein as soon as feasible following the commencement of seizures. The complete hemogram analysis was done using the Mindray BC-5800 auto hematology analyzer (Mindray Medical International Limited, Shenzhen, China).

RESULT

The cases group had significantly higher interleukin-4 (IL-4) concentrations (292.85 pg/mL) than controls (81.04 pg/mL), indicating a statistically significant difference (p<0.05), respectively. In the current research, case participants had a significantly lower mean level of interleukin-6 (IL-6) than control participants. The average IL-6 concentration in cases was 28.00 pg/mL, whereas in controls was 93.09pg/mL. Patients with FS have an important function for the cytokine network to perform.

CONCLUSION

The findings showed a significant difference in cytokine concentrations between patients with FS and control subjects, highlighting a potential link between the cytokine system and FS. Additionally, lower levels of IL-6 in case participants suggest a complex role of cytokines in FS, emphasizing the importance of the cytokine network in this condition.

TGF-β Activated Kinase 1 (TAK1) Is Activated in Microglia After Experimental Epilepsy and Contributes to Epileptogenesis

Increasing evidence suggests that inflammation promotes epileptogenesis. TAK1 is a central enzyme in the upstream pathway of NF-κB and is known to play a central role in promoting neuroinflammation in neurodegenerative diseases. Here, we investigated the cellular role of TAK1 in experimental epilepsy. C57Bl6 and transgenic mice with inducible and microglia-specific deletion of Tak1 (Cx3cr1^CreER:Tak1^fl/fl) were subjected to the unilateral intracortical kainate mouse model of temporal lobe epilepsy (TLE). Immunohistochemical staining was performed to quantify different cell populations. The epileptic activity was monitored by continuous telemetric electroencephalogram (EEG) recordings over a period of 4 weeks. The results show that TAK1 was activated predominantly in microglia at an early stage of kainate-induced epileptogenesis. Tak1 deletion in microglia resulted in reduced hippocampal reactive microgliosis and a significant decrease in chronic epileptic activity. Overall, our data suggest that TAK1-dependent microglial activation contributes to the pathogenesis of chronic epilepsy.

Association between indel polymorphism (rs145204276) in the promoter region of lncRNA GAS5 and the risk of febrile convulsion

BACKGROUND

This study aimed to explore the regulatory relationship between growth arrest special 5 (GAS5) and interleukin-1β (IL-1β) implicated in the development of febrile seizure (FS).

METHOD

The presence of FS and the genotype of GAS5 were used as two different indicators to divide the 50 newborn babies, recruited in this study, into different groups. The potential regulatory relationship among GAS5, miR-21, and IL-1β was identified by measuring their expression using quantitative reverse-transcription polymerase chain reaction and immunohistochemistry assays among different sample groups. Computational analyses and luciferase assays were also conducted to verify the interaction between GAS5, miR-21, and IL-1β.

RESULT

GAS5 and IL-1β expression was upregulated in cells collected from FS patients or genotyped as INS/DEL and DEL/DEL, whereas the expression of miR-21 was decreased in above samples, indicating a negative relationship between miR-21 and GAS5/IL-1β. Results of the computational analysis showed that miR-21 directly bound to and increased the expression of GAS5, whereas the expression of IL-1β was suppressed by miR-21. In the presence of GAS5, the expression of miR-21 was lowered, whereas the expression of IL-1β was increased.

CONCLUSION

The results obtained in this study supported the conclusion that GAS5 negatively regulated the expression of miR-21, which in turn negatively regulated the expression IL-1β. Therefore, the overexpression of GAS5 could decrease the magnitude of FS.

Reduced cerebrospinal fluid levels of interleukin-10 in children with febrile seizures

PURPOSE

The exact etiology of febrile seizures (FS) is still unclear. However, it is thought that cytokine network activation may have a causative role. Therefore, this study aimed to evaluate the levels of interleukin-12 (IL-12) as a proinflammatory cytokine, interleukin-10 (IL-10) as an anti-inflammatory cytokine, and interferon-β (IFN-β), a marker of toll-like receptor-3 activation as a host response to viruses. These cytokine levels were analyzed in the cerebrospinal fluid (CSF) of children after a FS.

METHODS

With the approval of the Human Research Ethics Committee, 76 patients with FS, who underwent lumbar puncture (LP) for the exclusion of central nervous system (CNS) infection, and who didn't have CSF pleocytosis, were included in the study. The control group consisted of 10 patients with similar ages, with an acute febrile illness and who required LP to exclude CNS infection. The analyses were made by the enzyme-linked immunoassay method.

RESULTS

Age, gender distribution and CSF IL-12 and IFN- β levels did not differ, but CSF IL-10 levels were significantly lower in the FS group as compared to the control group (0.78 ± 4.5 pg/ml, versus 27 ± 29 pg/ml, p < 0.0001).

CONCLUSION

The low-level of CSF IL-10, considering its anti-inflammatory properties, may play a role in the etiopathogenesis of FS.

The role of Mean Platelet Volume/platelet count Ratio and Neutrophil to Lymphocyte Ratio on the risk of Febrile Seizure

Systemic inflammatory response has been implicated as a contributor to the onset of febrile seizures (FS). The four novel indices of the inflammatory response such as, neutrophil-to-lymphocyte ratio (NLR), mean platelet volume (MPV), platelet count (PLT) ratio and red blood cell distribution width (RDW) have been investigated in FS susceptibility and FS types (simple febrile seizure and complex febrile seizure). However, the potential role of these inflammatory markers and MPV/PLT ratio (MPR) in Chinese children with FS has yet to be fully determined. This study investigated the relevance of NLR, MPV, PLT, MPR and RDW in febrile children with and without seizures. 249 children with FS and 249 age matched controls were included in this study. NLR and MPR were calculated from complete blood cell counts prior to therapy. Differences in age, gender and these inflammatory markers between the FS group and the control group were evaluated using the chi-square test, t-test or logistic regression analysis. Receiver Operating Characteristic (ROC) curve was used to determine the optimal cut-off value of NLR and MPR for FS risk. Interactions between NLR and MPR on the additive scale were calculated by using the relative excess risk due to interaction (RERI), the proportion attributable to interaction (AP), and the synergy index (S). It has been shown that the elevated NLR and MPR levels were associated with increased risk of FS. The optimal cut-off values of NLR and MPR for FS risk were 1.13 and 0.0335 with an area under the curve (AUC) of 0.768 and 0.689, respectively. Additionally, a significant synergistic interaction between NLR and MPR was found on an additive scale. The mean levels of MPV were lower and NLR levels were higher in complex febrile seizure (CFS) than simple febrile seizure (SFS), and the differences were statistically significant. ROC analysis showed that the optimal cut-off value for NLR was 2.549 with 65.9% sensitivity and 57.5% specificity. However, no statistically significant differences were found regarding average values of MPR and RDW between CFS and SFS. In conclusion, elevated NLR and MPR add evidence to the implication of white cells subsets in FS risk, and our results confirmed that NLR is an independent, albeit limited, predictor in differentiating between CFS and SFS. Moreover, NLR and MPR may have a synergistic effect that can influence the occurrence of FS.

Cytokine levels in febrile seizure patients: A systematic review and meta-analysis

PURPOSE

Febrile seizures (FSs) are the most common form of childhood seizures. During infection, both pro-inflammatory and anti-inflammatory cytokines are produced. Complex interactions among immune-inflammatory process, cytokine activation, and genetic factors are involved in the pathogenesis of FSs. The association between cytokines and FSs during childhood is inconclusive due to inconsistent results reported in different studies. We performed a systematic review and meta-analysis to determine an association between cytokines and FS in children.

METHODS

We searched PubMed, EMBASE, and Cochrane databases for studies published up to January 2017 using the following key words: ["cytokine" OR "interleukin" OR "tumor necrosis factor alpha" OR "interferon-gamma" OR "single nucleotide polymorphism"] AND ["febrile seizure" OR "febrile convulsion"] AND ["pediatric" OR "infant" OR "child"]. Standardized mead difference (SMD) and 95% confidence intervals (CI) were calculated using standard meta-analysis techniques.

RESULTS

A total of 6 studies enrolling 243 children with FS and 234 controls were included in the meta-analysis. A total of 4 different inflammatory mediators were. The results indicated that CSF IL-1β level and serum IL-6 level were significantly associated with FS (CSF IL-1β: SMD, 1.064; 95% CI, 0.217-1.611; P < 0.01, serum IL-6 SMD, 2.654; 95% CI, 2.332-2.975; P < 0.01).

CONCLUSION

The results of this meta-analysis suggest that CSF IL-1β level and serum IL-6 level are associated with an increased risk of FSs in children. Based on these results, it is expected that a therapeutic agent for specific cytokines could be developed in the future to prevent FS.

Analysis of plasma multiplex cytokines and increased level of IL-10 and IL-1Ra cytokines in febrile seizures

Background

Febrile seizures are the most common form of childhood seizures. Fever generation involves many cytokines, including both pro- and anti-inflammatory cytokines. Some of these cytokines also induce febrile seizures. We compared cytokine production in children with a fever alone (healthy control group) and febrile seizure children group. Also, we evaluated the cytokine level of children with a fever alone and febrile seizure history.

Methods

Fifty febrile seizure patients and 39 normal control patients who visited the emergency department of Konkuk University Hospital from December 2015 to December 2016 were included in this study. Blood was taken from the peripheral vessels of children in all groups within 1 h of the seizure, and serum was obtained immediately. Serum samples from patients with only a fever and a febrile seizure history (N = 13) and afebrile seizure controls (N = 12) were also analyzed.

Results

The serum IL-10 and IL-1Ra levels were significantly higher in the febrile seizure patients than in the fever-only control, fever only with a febrile seizure history, and afebrile seizure groups (p < 0.05). The serum IFN-γ and IL-6 levels were significantly higher in the febrile seizure patients than in the afebrile seizure group (p < 0.05). The serum IL-8 levels were higher in the febrile seizure patients than in the fever only controls (p < 0.05).

Conclusions

The serum levels of the IFN-γ, IL-6, and IL-8 pro-inflammatory cytokines and the serum levels of the IL-10 and IL-1Ra anti-inflammatory cytokines were significantly higher in the febrile seizure children. Furthermore, the serum level of IL-1Ra was more increased in the febrile seizure group than in the same patients with only a fever. Our data suggest that increased serum IL-10 and IL-1Ra may play potential roles as anti-inflammatory cytokines in a compensation mechanism that shortens the seizure duration or prevents a febrile seizure attack. Therefore, anti-inflammatory cytokines, including IL-10 and IL-1Ra, have potential as therapeutic targets for the prevention of seizures and nervous system development of children.

Interleukin-1β and interleukin-1receptor antagonist polymorphisms in Egyptian children with febrile seizures: A case-control study

Febrile seizure is the most common seizure disorder of childhood. Of the pro-inflammatory cytokines, interleukin-1 is defined as the first endogenous pyrogen.We designed this study to investigate single-nucleotide polymorphisms (SNPs) situated at positions -31 (C/T), and -511 (C/T) of interleukin-1beta (IL-1β) gene promoter and interleukin-1receptor antagonist (IL-1RA) gene variable number of tandem repeats in intron 2 (VNTR); to determine whether these polymorphisms could be a marker of susceptibility to febrile seizures in Egyptian children and we also measured the serum level of IL-1β to assess its relation to such polymorphisms.This was a case-control study included 155 patients with febrile seizure, and matched with age, sex, ethnicity 155 healthy control subjects. IL-1β promoter at positions -31 (C/T), -511 (C/T), and IL-1RA gene VNTR polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), while the serum IL-1β levels were measured by enzyme-linked immunosorbent assay (ELISA) method.The frequency of the IL-1β-511 TT genotype and T allele at the same position were observed to be increased in patients with febrile seizures (FS) compared with the control group (odds ratio [OR]: 3.96; 95% confidence interval [CI]: 1.68-9.5; P = 0.001 for the TT genotype and OR: 1.65; 95% CI: 1.18-2.3; P = 0.003 for the T allele, respectively). The IL-1 RA II/II homozygous variant and IL-1 RA allele II were overrepresented in patients with FS than control group (OR: 4.02; 95% CI: 1.78-9.15; P = 0.001and OR: 1.73; 95% CI: 1.24-2.4; P = 0.001, respectively). We found a significant positive association between the IL-1 RA II/II genotype and susceptibility to FS in sporadic cases as did allele II at the same position (OR: 5.04; 95% CI: 2.1-12.5 for the IL-1 RA II/II genotype; P = 0.001) and (OR: 1.94; 95% CI: 1.3-2.8 for the allele II; P = 0.001, respectively). Carriers of the IL-1RA II/II homozygous variant and allele II had significantly higher serum levels of IL-1β compared with those with other genotypes and alleles.We demonstrate for the first time that the presence of a T allele or TT genotype at -511 of IL-1β promoter and IL-1RA II/II genotype constitute risk factors for developing FS in Egyptian children.

Experimental febrile seizures impair interastrocytic gap junction coupling in juvenile mice

Prolonged and focal febrile seizures (FSs) have been associated with the development of temporal lobe epilepsy (TLE), although the underlying mechanism and the contribution of predisposing risk factors are still poorly understood. Using a kainate model of TLE, we previously provided strong evidence that interruption of astrocyte gap junction-mediated intercellular communication represents a crucial event in epileptogenesis. To elucidate this aspect further, we induced seizures in immature mice by hyperthermia (HT) to study the consequences of FSs on the hippocampal astrocytic network. Changes in interastrocytic coupling were assessed by tracer diffusion studies in acute slices from mice 5 days after experimental FS induction. The results reveal that HT-induced FSs cause a pronounced reduction of astrocyte gap junctional coupling in the hippocampus by more than 50%. Western blot analysis indicated that reduced connexin43 protein expression and/or changes in the phosphorylation status account for this astrocyte dysfunction. Remarkably, uncoupling occurred in the absence of neuronal death and reactive gliosis. These data provide a mechanistic link between FSs and the subsequent development of TLE and further strengthen the emerging view that astrocytes have a central role in the pathogenesis of this disorder. © 2016 Wiley Periodicals, Inc.

Association of Interleukin-1 Gene Cluster and Interleukin-1 Receptor Polymorphisms With Febrile Seizures

Interleukin-1 (IL-1) plays a key role in inflammation, has an effect on a wide variety of cells, and often leads to tissue destruction. While the ratio between IL-1 and IL-1Ra could influence the development of different diseases of the central nervous system, its gene polymorphisms were investigated in a group of patients with febrile seizures. Ninety patients with febrile seizures were enrolled and compared with 140 controls. The allele and genotype frequency of single nucleotide polymorphisms within the IL-1α, β, IL-1 R and IL-1Ra gene were determined. The frequency of the IL-1Ra/C allele at position Mspa-I 11100 was decreased significantly (P= .002) and the IL-1Ra/T frequency was significantly increased in patients (P= .002). In addition, the CT genotype frequency at the same position was significantly overrepresented in controls compared to patients (P= .001). Certain alleles and genotypes in the IL-1 gene were overrepresented in patients with febrile seizures, which possibly could predispose individuals to this disease.

Inflammatory mediators in human epilepsy: A systematic review and meta-analysis

BACKGROUND

Accumulating evidence suggests a role for inflammation in the pathophysiology of epilepsy.

METHODS

We performed a systematic review and meta-analysis of studies that investigated inflammatory mediators in human epilepsy. Studies reporting on inflammatory mediators in serum, cerebrospinal fluid or brain tissue of epilepsy patients were included. Studies comparing patients to controls were included in a meta-analysis.

RESULTS

66 articles reporting on 1934 patients were included. IL-1ra, IL-1β, IL-6, IL-10, IFN-γ and TNF-α were the most extensively investigated proteins. Elevated levels for IL-1ra, IL-1β, IL-6 and CXCL8/IL-8 were reported in several different epilepsy etiologies and media, while other proteins were specifically increased for one etiology. IL-1α, IL-7 and IL-13, as well as the chemokines CCL2-5, -19 and -22, were increased exclusively in brain tissue. In an aggregate meta-analysis, we found significantly different protein levels for serum IL-6, IL-17 and CSF IL-1β and IL-10.

CONCLUSION

Inflammatory pathways are involved in epilepsy. Future studies may further clarify their role, and prove potential of targeted anti-inflammatory treatment.

Alterations in pain responsiveness and serum biomarkers in juvenile myoclonic epilepsy: an age- and gender-matched controlled pilot study

Introduction: Serum levels of several biomarkers along with sensory responsiveness were investigated in juvenile myoclonic epilepsy patients in comparison with healthy controls. Methods: Ten epileptic patients (36.1 ± 3.4 years) and ten gender- and age-matched healthy controls were recruited. Mechanical sensitivity, cold pressor tolerance and serum levels of BDNF, CGRP, PGE2, S100B and TNF-α were investigated. Results: Mechanical sensitivity to pinprick was lower in patients (p < 0.05) while cold pain tolerance threshold was higher. Serum level of BDNF was higher in patients compared with controls (p < 0.01). The same pattern was evident for CGRP (p < 0.05). Serum level of PGE2 was lower in patients (p < 0.01). Conclusion: Juvenile myoclonic epilepsy patients had an altered serum biomarker pattern and sensory perception in comparison with controls.

Serum adiponectin, leptin, and interleukin 6 levels as adipocytokines in children with febrile seizures: The role of adipose tissue in febrile seizures

Proinflammatory and anti-inflammatory cytokines have an important role in the pathogenesis of febrile seizures (FS). Adipocytokines like interleukin 6 (IL-6), leptin, and adiponectin released from adipose tissue play a role in inflammation. This study aimed to assess the probable role of adipose tissue in children with FS. We measured serum IL-6, leptin, and adiponectin levels and evaluated clinical and laboratory findings in children with FS (n = 32) and compared the results with the values of children of the same age with febrile illness without seizures (febrile control, FC; n = 26) and healthy control group (HC; n = 29). The serum levels of white blood cells, C-reactive protein, IL-6, leptin, and adiponectin were found to be significantly higher, while serum hemoglobin (Hb) levels were found to be significantly lower in FS and FC groups than in the HC group (p < 0.001). When we compared the FS with the FC group, the serum Hb levels were significantly lower in the FS group than those in the FC group (p = 0.001). There was no significant difference between the FS and FC group with regard to the serum levels of these adipocytokines (p > 0.05). Our data showed that elevated levels of these adipocytokines as acute phase reactants in FS and FC groups did not contribute to the development of FS.

Risk of subsequent asthma in children with febrile seizures: a nationwide population-based retrospective cohort study

BACKGROUND

No study has reported a relationship between febrile seizures and asthma; thus, we examined the association between these two disorders.

METHODS

We identified 991 cases of children with febrile seizures as the case cohort, and the control group was matched according to age, sex, urbanization level, and their parents' occupation at a 1:4 ratio. We applied the Cox proportional hazards regression model to estimate the hazard ratios and 95% confidence intervals for asthma among the children with febrile seizures.

RESULTS

After 11 years of follow-up, the asthma incidence in the febrile seizure group was approximately 5% higher than that in the control group (log-rank test, P < 0.0001). The risk of asthma in the febrile seizure group was 1.41 times higher than that in the control group (95% confidence interval, 1.21-1.65; P < 0.001). Furthermore, the risk of asthma development increased (0.96 vs 3.62) in conjunction with the frequency of febrile seizure-related medical visits (one to two visits vs more than four visits; P < 0.0001).

CONCLUSION

Febrile seizures may be associated with an increase in the risk of future asthma occurrence in children. We observed a significantly higher cumulative incidence of asthma occurrence in children with more febrile seizure-related medical visits.

Tumor necrosis factor-α and interleukin-6 concentrations in cerebrospinal fluid of dogs after seizures

BACKGROUND

Idiopathic and acquired epilepsy are common in dogs. Up to 30% of these dogs are refractory to pharmacological treatment. Accumulating experimental evidence indicates that brain immune response and presence of inflammatory mediators decrease the threshold for individual seizures and contribute to epileptogenesis.

HYPOTHESIS

Dogs with seizures have higher cerebrospinal interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations compared to dogs with no seizures.

METHODS

A prospective double blinded study; cerebrospinal fluid (CSF) and serum IL-6, TNF-α and total protein (TP) concentrations were measured by a blinded investigator for the study group and CSF IL-6 and TNF-α levels and TP concentrations were measured in the control group (CG).

ANIMALS

Dogs presented with seizures that had enough CSF collected to allow analysis were included in the study group. Twelve apparently healthy, quarantined, stray dogs served as control (CG).

RESULTS

Cerebrospinal fluid TNF-α and IL-6 concentrations were significantly higher (P = .011, P = .039) in dogs with seizures (0 ± 70.66, 0.65 ± 10.93 pg/mL) compared to the CG (0 ± 19, 0.73 ± 0.55 pg/mL). When assessing cytokine concentrations of specifically the idiopathic epilepsy (IE) dogs compared to the CG, only TNF-α concentrations (8.66 ± 62, 0 ± 19 pg/mL) were significantly higher (P = .01). CSF TP concentrations were not significantly higher in the study dogs compared to the CG.

CONCLUSIONS AND CLINICAL IMPORTANCE

Higher TNF-α and IL-6 concentration in the CSF of dogs with naturally occurring seizures. The higher supports the hypothesis that inflammatory processes through certain mediators play a role in the pathogenesis of seizures in dogs.

Serum interleukin-1beta and tumor necrosis factor-alpha in febrile seizures: is there a link?

Purpose

Febrile seizures are induced by fever and are the most common type of seizures in children. Although numerous studies have been performed on febrile seizures, their pathophysiology remains unclear. Recent studies have shown that cytokines may play a role in the pathogenesis of febrile seizures. The present study was conducted to identify potential links between serum interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and febrile seizures.

Methods

Ninety-two patients with simple or complex febrile seizures (46 patients per seizure type), and 46 controls with comparable age, sex, and severity of temperature were enrolled.

Results

The median concentrations of serum IL-1β in the simple, complex febrile seizure, and control groups were 0.05, 0.1, and 0.67 pg/mL, respectively (P=0.001). Moreover, the median concentrations of TNF-α in the simple, complex febrile seizure, and control groups were 2.5, 1, and 61.5 pg/mL, respectively (P=0.001). Furthermore, there were significant differences between the case groups in serum IL-1β and TNF-α levels (P<0.05).

Conclusion

Unlike previous studies, our study does not support the hypothesis that increased IL-1β and TNF-α production is involved in the pathogenesis of febrile seizures.

IL-1β: an important cytokine associated with febrile seizures?

Febrile seizures (FSs) are the most common convulsions in childhood. Studies have demonstrated a significant relationship between a history of prolonged FSs during early childhood and temporal sclerosis, which is responsible for intractable mesial temporal lobe epilepsy. It has been shown that interleukin-1β (IL-1β) is intrinsically involved in the febrile response in children and in the generation of FSs. We summarize the gene polymorphisms, changes of IL-1β levels and the putative role of IL-1β in the generation of FSs. IL-1β could play a role either in enhancing or in reducing neural excitability. If the enhancing and reducing effects are balanced, an FS does not occur. When the enhancing effect plays the leading role, an FS is generated. A mild imbalance can cause simple FSs while a severe imbalance can cause complex FSs and febrile status epilepticus. Therefore, anti-IL-1β therapy may help to treat FSs.

Increased association between febrile convulsion and allergic rhinitis in children: a nationwide population-based retrospective cohort study

BACKGROUND AND OBJECTIVES

Febrile convulsions and allergic rhinitis are both common childhood disorders and both are considered as generally benign disorders. Yet, especially in the case of allergic rhinitis, adverse effects on school performance and limited socialization are found. The relationship between febrile convulsions and allergic rhinitis has not been previously reported; thus, this article seeks to explore the association between these two disorders by collecting data from the Taiwanese nationwide cohort database.

METHODS

A total of 1304 children with febrile convulsions were identified as the case cohort, and controls were matched based on age, sex, urbanization levels, and parents' occupation on a 1 to 4 ratio. Cox's proportional hazards regression model was used to estimate the hazard ratio and confidence interval of allergic rhinitis disorder among children with febrile convulsions.

RESULTS

During an average 6.7 years follow-up period, the incidence of allergic rhinitis in the febrile convulsions case group was higher (65.16 vs 51.45 per 1000 person-years). After 11 years of follow-up, the allergic rhinitis incidence in the febrile convulsion patients was approximate 4% higher than controls (log-rank test P < 0.0001). Risk of allergic rhinitis in the febrile convulsions group was found to be 1.21 times higher than in the control group (95% confidence interval, 1.08-1.36). This risk of allergic rhinitis development is further increased (0.94 vs 18.9) with frequency of febrile convulsions-related medical visits (one to three visits vs more than three visits, P < 0.0001).

CONCLUSION

Febrile convulsions may be associated with allergic rhinitis occurrence in children. Children with more than three febrile convulsion-related medical visits had a significantly higher cumulative incidence of allergic rhinitis. Both disorders have previously been reported to have similar cytokine profiles and specific viral infection association. More studies are required to explore a possible link between the two disorders.

Causes of CNS inflammation and potential targets for anticonvulsants

Inflammation is one of the most important endogenous defence mechanisms in an organism. It has been suggested that inflammation plays an important role in the pathophysiology of a number of human epilepsies and convulsive disorders, and there is clinical and experimental evidence to suggest that inflammatory processes within the CNS may either contribute to or be a consequence of epileptogenesis. This review discusses evidence from human studies on the role of inflammation in epilepsy and highlights potential new targets in the inflammatory cascade for antiepileptic drugs. A number of mechanisms have been shown to be involved in CNS inflammatory reactions. These include an inflammatory response at the level of the blood-brain barrier (BBB), immune-mediated damage to the CNS, stress-induced release of inflammatory mediators and direct neuronal dysfunction or damage as a result of inflammatory reactions. Mediators of inflammation in the CNS include interleukin (IL)-1β, tumour necrosis factor-α, nuclear factor-κB and toll-like receptor-4 (TLR4). IL-1β, BBB and high-mobility group box-1-TLR4 signalling appear to be the most promising targets for anticonvulsant agents directed at inflammation. Such agents may provide effective therapy for drug-resistant epilepsies in the future.

Selenium and leptin levels in febrile seizure: a case-control study in children

PURPOSE

Febrile seizures (FS) are seizures that occur between the age of 6 and 60 months, but its pathophysiology still is not fully understood. There is limited information about the correlation between levels of selenium and leptin with FS. This study aimed to determine the relationship between serum levels of selenium and leptin in children with FS.

METHODS

This case-control study was conducted in a University Hospital in Shahrekord, Iran, in 2011. The serum levels of selenium and leptin of 25 children with simple febrile seizure (case group) were compared with 25 febrile children without seizure (control group) in acute phase and after three months. The levels of serum selenium and leptin were measured by flame atomic absorption spectrophotometer and enzyme-linked immunosorbent assay method, respectively.

RESULTS

In acute phase, the mean serum level of selenium in case and control groups were 95.88±42.55 and 113.25±54.43 µg/dL, respectively, and difference was not significant (P=0.415), but after three months, this level had a significant increase in both groups (P<0.001). In acute phase, the mean serum leptin level in case and control groups were 0.94±0.5 and 0.98±0.84 ng/mL, respectively, but difference was not significant (P=0.405). After three months, serum leptin level had no significant change in both groups (P=0.882).

CONCLUSION

These observations suggest that serum levels of selenium and leptin have not specific relation with FS but overllay is lower, however, further study is recommended. Also selenium level in stress and acute phase was significantly lower than recovery phase.

Comparison of serum zinc levels measured by inductively coupled plasma mass spectrometry in preschool children with febrile and afebrile seizures

Background

Changes in levels of trace elements have been proposed to underlie febrile seizures. Particularly, low zinc levels have been proposed as related factor of febrile seizure. In this study, we investigated whether mean serum zinc levels differed between children with febrile seizure and afebrile seizure.

Methods

Using inductively coupled plasma mass spectrometry, serum zinc levels were measured in 288 children who had been diagnosed with febrile seizures (N=248) and afebrile seizures (N=40). Mean serum zinc levels were compared between the 2 groups.

Results

Mean serum zinc level was 60.5±12.7 µg/dL in the febrile seizure group and 68.9 ±14.5 µg/dL in the afebrile seizure group. A significant difference in serum zinc levels was observed between the febrile and afebrile seizure groups (P<0.001).

Conclusions

Zinc levels in children with febrile seizure were significantly lower than those in children with afebrile seizure.

Lack of association between TNF-α gene polymorphisms at position -308 A, -850T and risk of simple febrile convulsion in pediatric patients

Background:

Febrile convulsions (FCs), occurring between 6 months and 6 years of age is the most common seizure disorder during childhood. The febrile response is thought to be mediated by the release of pyrogenic cytokines, such as tumor necrosis factor and interleukin-1 (IL-1). There is a significant relationship between genetic components for susceptibility of FCs and different report mutation. We investigated association between two polymorphisms in the tumor necrosis factor (TNF)-α promoter region (G-308A, C-850T) and FCs in the southwest area of Iran.

Materials and Methods:

In this matched case–control study, 100 patients with febrile convulsion as case group and 130 healthy children as control group were enrolled in the study. Peripheral blood samples were collected and DNA was extracted by standard phenol–chloroform method. The genotype and allele frequencies of TNF- α polymorphisms in case and control groups were determined by using PCR-RFLP (polymerase chain reaction restriction fragment length polymorphism) method. Statistical analysis was done using Chi-square test.

Results:

The average age of case and control groups were 3.4 ± 1.4 and 3.4 ± 1.2 years, respectively. There was no significant difference between age and sex in both the groups (P > 0.05). A family history of febrile convulsion was detected in 44% of patients. Moreover, the simple febrile convulsion was detected in 85% of the case group.

Conclusion:

RFLP analysis of TNF- α promoter region polymorphisms, considering P = 0.146 and P = 0.084 for G-308A and C-850T, respectively, showed no correlation between TNF- α polymorphisms and predisposition to simple febrile, based on the kind of convulsion (atypical and simple febrile convulsion). We found a significant relation between genotype distribution of G-308A and atypical febrile convulsion in case group (P = 0.04). A significant correlation between genotype distribution of G-308A and atypical febrile convulsion in the case group was found, but there was no correlation between TNF- α polymorphisms at positions of -308A, and 850T and predisposition to simple febrile convulsion. Further studies are needed to understand clinical usefulness of this correlation.

Increased levels of HMGB1 and pro-inflammatory cytokines in children with febrile seizures

OBJECTIVE

Febrile seizures are the most common form of childhood seizures. Fever is induced by pro-inflammatory cytokines during infection, and pro-inflammatory cytokines may trigger the development of febrile seizures. In order to determine whether active inflammation, including high mobility group box-1 (HMGB1) and pro-inflammatory cytokines, occurs in children with febrile seizures or epilepsy, we analyzed cytokine profiles of patients with febrile seizures or epilepsy.

METHODS

Forty-one febrile seizure patients who visited the emergency department of Seoul National University Boramae Hospital from June 2008 to May 2009 were included in this study. Blood was obtained from the febrile seizure child patients within 30 minutes of the time of the seizure; subsequently, serum cytokine assays were performed. Control samples were collected from children with febrile illness without convulsion (N = 41) and similarly analyzed. Serum samples from afebrile status epilepticus attacks in intractable epilepsy children (N = 12), afebrile seizure attacks in generalized epilepsy with febrile seizure plus (GEFSP) children (N = 6), and afebrile non-epileptic controls (N = 7) were also analyzed.

RESULTS

Serum HMGB1 and IL-1β levels were significantly higher in febrile seizure patients than in fever only controls (p < 0.05). Serum IL-6 levels were significantly higher in typical febrile seizures than in fever only controls (p < 0.05). Serum IL-1β levels were significantly higher in status epilepticus attacks in intractable epilepsy patients than in fever only controls (p < 0.05). Serum levels of IL-1β were significantly correlated with levels of HMGB1, IL-6, and TNF-α (p < 0.05).

CONCLUSIONS

HMGB1 and pro-inflammatory cytokines were significantly higher in febrile seizure children. Although it is not possible to infer causality from descriptive human studies, our data suggest that HMGB1 and the cytokine network may contribute to the generation of febrile seizures in children. There may be a potential role for anti-inflammatory therapy targeting cytokines and HMGB1 in preventing or limiting febrile seizures or subsequent epileptogenesis in the vulnerable, developing nervous system of children.

Interleukin (IL)-1beta, IL-1 receptor antagonist, IL-6, IL-8, IL-10, and tumor necrosis factor alpha gene polymorphisms in patients with febrile seizures

Inflammation and genetics may play a role in the pathogenesis of febrile seizures (FSs). We aimed to test whether interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL-1 Ra), IL-6 promoter, IL-8, IL-10, or tumor necrosis factor (TNF) gene polymorphisms could be used as markers of susceptibility to FSs. An association study was performed among a cohort of 104 patients with FSs and 143 normal control subjects. There was no significant difference between patients and controls in the distribution of allele frequencies of the IL-1beta promoter, IL-1beta exon 5, IL-6 promoter, IL-8, IL-10, or TNF-alpha gene polymorphisms. In contrast, the IL-1 Ra-I homozygote was more frequent in patients with FSs than in healthy controls (93.2% vs. 83.92%, chi(2)=4.51, P=0.034). In addition, individuals homozygous for the IL-1 Ra-I genotype were more than twice as likely to develop FSs than individuals heterozygous for the IL-1 Ra-I/II genotype (OR, 2.63, 95% CI: 1.08-6.39; chi(2)=4.55, P=0.033). We conclude that the IL-1 Ra gene might be one of the useful markers for predicting susceptibility to FSs.

Lovastatin decreases the synthesis of inflammatory mediators in the hippocampus and blocks the hyperthermia of rats submitted to long-lasting status epilepticus

Statins may act on inflammatory responses, decreasing oxidative stress and also reducing temperature after a brain ischemic insult. Previous data have indicated that statins protect neurons from death during long-lasting status epilepticus (SE) and attenuate seizure behaviors in animals treated with kainic acid. In this context, the study described here aimed to investigate the effect of lovastatin on body temperature and on mRNA expression levels of hippocampal cytokines such as interleukin-1β, interleukin-6, tumor necrosis factor α, and kinin B1 and B2 receptors of rats submitted to pilocarpine-induced SE. Quantitative real-time polymerase chain reaction showed a significant decrease in mRNA expression of interleukin-1β, interleukin-6, tumor necrosis factor α, and kinin B1 receptor in animals with SE treated with lovastatin, compared with untreated animals with SE (P<0.001). Lovastatin also reduced SE-induced hyperthermia, indicating that mechanisms related to brain protection are triggered by this drug under conditions associated with acute excitotoxicity or long-lasting SE.

Correlation between serum selenium level and febrile seizures

Febrile seizures are the most common form of childhood seizures. Although the literature associates certain micronutrients with febrile seizures, there is limited information about the effects of such micronutrients. This study aimed to determine the relationship between serum selenium level and simple febrile seizures in children. This case-control study was conducted in the Children's Hospital in Qazvin, Iran, in 2008. The serum selenium level of 30 children who experienced simple febrile seizures (case group) was measured and compared with that of 30 febrile children without seizure (control group). The serum selenium level was measured by flame atomic absorption spectrophotometer. Data were analyzed by using t-test. Mean ± standard deviation of serum selenium level in the case and control groups was 44.4 ± 10.9 and 63 ± 9.78 μg/dL, a significant difference (P < 0.001). In the case group, 18/30 patients (60%) had a serum selenium level below the norm of 46 μg/dL, whereas serum selenium level in the entire control group was within the normal range (P < 0.01). The serum selenium level in the children who had simple febrile seizures was significantly lower than in the nonseizure control group. It seems that there is an association between serum selenium deficiency and simple febrile seizures; however, further study is recommended.

Epileptogenesis provoked by prolonged experimental febrile seizures: mechanisms and biomarkers

Whether long febrile seizures (FSs) can cause epilepsy in the absence of genetic or acquired predisposing factors is unclear. Having established causality between long FSs and limbic epilepsy in an animal model, we studied here if the duration of the inciting FSs influenced the probability of developing subsequent epilepsy and the severity of the spontaneous seizures. We evaluated if interictal epileptifom activity and/or elevation of hippocampal T2 signal on magnetic resonance image (MRI) provided predictive biomarkers for epileptogenesis, and if the inflammatory mediator interleukin-1beta (IL-1beta), an intrinsic element of FS generation, contributed also to subsequent epileptogenesis. We found that febrile status epilepticus, lasting an average of 64 min, increased the severity and duration of subsequent spontaneous seizures compared with FSs averaging 24 min. Interictal activity in rats sustaining febrile status epilepticus was also significantly longer and more robust, and correlated with the presence of hippocampal T2 changes in individual rats. Neither T2 changes nor interictal activity predicted epileptogenesis. Hippocampal levels of IL-1beta were significantly higher for >24 h after prolonged FSs. Chronically, IL-1beta levels were elevated only in rats developing spontaneous limbic seizures after febrile status epilepticus, consistent with a role for this inflammatory mediator in epileptogenesis. Establishing seizure duration as an important determinant in epileptogenesis and defining the predictive roles of interictal activity, MRI, and inflammatory processes are of paramount importance to the clinical understanding of the outcome of FSs, the most common neurological insult in infants and children.

Serum trace element levels in febrile convulsion

Febrile convulsion is the most common disorder in childhood with good prognosis. There are different hypotheses about neurotransmitters and trace element changes in biological fluids which can have a role in pathogenesis of febrile convulsion. In this study, serum selenium, zinc, and copper were measured by atomic absorption spectrometry in the children with febrile convulsion (n = 30) and in the control group (n = 30). The age and sex of the subjects were registered. Selenium and zinc were found to be significantly lower in febrile convulsion cases than in the control group (p < 0.0001 and p < 0.0001, respectively). There was no significant difference in the value of copper between the two groups (p = 0.16). While selenium and zinc levels were 44.92 +/- 10.93 microg/l and 66.13 +/- 18.97 microg/dl in febrile convulsion, they were found to be 62.98 +/- 9.80 microg/l and 107.87 +/- 28.79 microg/dl in healthy children. Meanwhile, copper levels were 146.40 +/- 23.51 microg/dl in the patients and 137.63 +/- 24.19 microg/dl in the control group, respectively. This study shows that selenium and zinc play an important role in the pathogenesis of febrile convulsion.

Contributions of peripheral inflammation to seizure susceptibility: cytokines and brain excitability

Inflammation is an important factor in the pathophysiology of seizure generation and epileptogenesis. While the role of CNS inflammation is well acknowledged as an important factor in seizure pathophysiology, less is known about the role of peripheral inflammation. Systemic inflammation induces a mirror inflammatory response in the brain that might have transient or long-term effects on seizure susceptibility. The focus of our laboratory research is the study of the interaction of systemic inflammatory events with neuronal excitability and seizure susceptibility. In this paper we provide a review of our findings and discuss possible mechanisms.

Etiology and site of temporal lobe epilepsy influence postictal cytokine release

Inflammatory mechanisms are involved in the pathogenesis of epilepsy. Vice versa, immune functions are regulated by the brain. We measured postictal changes in serum levels of the immuno-modulating cytokines IL-1beta, IL-6 and TNFalpha in patients with well-defined temporal lobe epilepsy (TLE) and determined modifying factors. Serum levels of IL-1beta, IL-6 and TNFalpha were quantified by ELISA at baseline as well as immediately, 1h and 24h after a complex partial (CPS) or secondary generalized tonic-clonic seizure (GTCS) during video-EEG monitoring in 25 patients suffering from temporal epilepsy. IL-6 increased by 51% immediately after the seizure (p<0.01) and remained elevated for 24h. This increase lacked in patients with hippocampal sclerosis (HS; n=16, mean increase 28%, p>0.5, vs. 112%, p<0.01 in patients without HS). IL-6 levels were higher after right-sided seizures as compared to left-sided seizures 24h after the seizure (8.7pg/mL vs. 3.4pg/mL, p<0.05). In patients taking valproate (VPA, n=9), the levels of IL-1beta were higher as compared to patients not treated with VPA. The results suggest a relationship between the cytokine system and characteristics of TLE such as side and pathology.

Febrile seizures: mechanisms and relationship to epilepsy

Studies of febrile seizures have been driven by two major enigmas: first, how these most common of human seizures are generated by fever has not been known. Second, epidemiological studies have linked prolonged febrile seizures with the development of temporal lobe epilepsy, yet whether long or recurrent febrile seizures cause temporal lobe epilepsy has remained unresolved. To investigate these questions, a model of prolonged (complex) febrile seizures was developed in immature rats and mice, permitting mechanistic examination of the potential causal relationships of fever and seizures, and of febrile seizures and limbic epilepsy. Although the model relied on hyperthermia, it was discovered that the hyperthermia-induced secretion of endogenous fever mediators including interleukin-1beta, which contributed to the generation of these 'febrile' seizures. In addition, prolonged experimental febrile seizures provoked epilepsy in a third of the animals. Investigations of the mechanisms of this epileptogenesis demonstrated that expression of specific ion (HCN) channels and of endocannabinoid signaling, may be involved. These may provide novel drug targets for intervention in the epileptogenic process.

The role of interleukin-1 in seizures and epilepsy: a critical review

Interleukin-1 (IL-1) has a multitude of functions in the central nervous system. Some of them involve mechanisms that are related to epileptogenesis. The role of IL-1 in seizures and epilepsy has been investigated in both patients and animal models. This review aims to synthesize, based on the currently available literature, the consensus role of IL-1 in epilepsy. Three lines of evidence suggest a role for IL-1: brain tissue from epilepsy patients and brain tissue from animal models shows increased IL-1 expression after seizures, and IL-1 has proconvulsive properties when applied exogeneously. However, opposing results have been published as well. More research is needed to fully establish the role of IL-1 in seizure generation and epilepsy, and to explore possible new treatment strategies that are based on interference with intracellular signaling cascades that are initiated when IL-1 binds to its receptor.

Interleukin-10 is associated with resistance to febrile seizures: genetic association and experimental animal studies

PURPOSE

Febrile seizures (FS) are the most common form of childhood convulsions. Many reports have shown that a proinflammatory cytokine, interleukin-1 (IL-1) beta, may have a facilitatory effect on the development of FS. We have previously shown that the IL1B -511C/T single nucleotide polymorphism (SNP) is associated with simple FS of sporadic occurrence. The balance between pro- and antiinflammatory cytokines influences the regulation of infections and could, therefore, play a role in the pathogenesis of FS. Here, to determine whether pro- and antiinflammatory cytokine genes are responsible for the susceptibility to FS, we have performed an association study on functional SNPs of cytokine genes in FS patients and controls.

METHODS

The promoter SNPs of four inflammatory cytokine genes (IL6 -572C/G, IL8 -251A/T, IL10 -592A/C and TNFA -1037C/T) were examined in 249 patients with FS (186 simple and 63 complex FS) and 225 controls. Because the IL10 -592 SNP showed a positive association with FS, two additional SNPs (IL10 -1082A/G and -819T/C) were subjected to haplotype analysis. Furthermore, we examined the in vivo role of IL-10 in hyperthermia-induced seizures using immature animal models.

RESULTS

The frequencies of the IL10 -592C allele and -1082A/-819C/-592C haplotype were significantly decreased in FS as compared with in controls (p = 0.014 and 0.013, respectively). The seizure threshold temperature in the IL-10-administered rats was significantly higher than that in the saline-treated control ones (p = 0.027).

CONCLUSIONS

The present study suggests that IL-10 is genetically associated with FS and, contrary to IL-1beta, confers resistance to FS.

Lymphocytes subsets in children with febrile convulsions

In this study, lymphocytes subsets including blood CD3, CD4, CD8, CD16, CD19, and CD56 values were analyzed in children with febrile convulsion (FC) to determine whether there was the association of lymphocytes subsets in the pathogenesis of FC. The study includes 48 children with FC, and 55 healthy age matched control subjects, followed in Yüzüncü Yil University, Faculty of Medicine, Department of Pediatrics between October 2003 and June 2004. Blood CD3, CD4, CD8, CD16, CD19, and CD56 values were examined in the study and control groups. The analyses were performed in the Hematology Laboratory, Yüzüncü Yil University Faculty of Medicine, with flow cytometer device (Coulter Epics XL2, Flow Cytometer). A total of 48 children [17 girls (35.5%) and 31 boys (64.5%)], aged 6 months to 60 months (mean 22.20 +/- 13.75 months) with FC and 55 healthy children [28 girls (51%) and 27 boys (49%)], aged 6 months to 60 months (mean 28.87 +/- 17.04 months) were included in the study. When compared with the control group, the study found significantly decreased blood CD3 and CD4 values in the study group (p <.05). However, there was not significant difference in CD8, CD16, CD19, and CD56 values between the control and study groups (p >.05). When comparing the children with and without positive family history for FC, the study did not find any difference for all CD values between the groups (p >.05). Similarly, there was not significant difference in CD values between the children with simple and complex FC (p >.05). The findings suggested that decreased blood CD3 and CD4 values might be responsible for the infections connected with FC or that they might be related to the pathogenesis of FC in some children.

Plasma interleukin-1beta levels in children with febrile seizures

Proinflammatory and anti-inflammatory cytokines regulate the febrile response during infection. In this study, the role of cytokines in the pathogenesis of febrile seizures was investigated, through comparing levels of interleukin-1beta in the peripheral blood of children with febrile seizures and in a matched control group of children with febrile illnesses without seizures. The study included 33 children with febrile seizures (mean +/- SD, 29.94 +/- 14.9 months) and 38 controls with comparable age, sex, and type of infection. A laboratory workup for the diagnosis of infection was performed, and interleukin-1beta levels were assessed by enzyme-linked immunosorbent assay for the patients and the control groups immediately on arrival at the hospital. The plasma levels of interleukin-1beta were comparable in the patients and the control group (mean +/- SD, 7.321 +/- 3.123 and 8.087 +/- 4.8 pg/mL, respectively). Furthermore, there was no significant difference when comparing the plasma levels of interleukin-1beta in patients with simple and complex types of febrile seizures. Plasma interleukin-1beta levels did not show a significant correlation to either the duration of the last seizure, the number of the previous attacks of febrile convulsion, or the degree of temperature. However, interleukin-1beta levels were negatively correlated to the duration from the last seizure attack (r = -.8). Thus, the results of the present study do not support the hypothesis that increased production of interleukin-1beta is involved in the pathogenesis of febrile seizures in children.

Kinin B1 and B2 receptors are overexpressed in the hippocampus of humans with temporal lobe epilepsy

Molecular biology tools have been employed to investigate the participation of peptides in human temporal lobe epilepsy (TLE). Active polypeptides and their receptors have been related to several brain processes, such as inflammation, apoptosis, brain development, K(+) and Ca(2+) channels' activation, cellular growth, and induction of neuronal differentiation. Previous works have shown a neuroprotector effect for kinin B2 receptor and a deleterious, pro-epileptogenic action for kinin B1 receptor in animal models of TLE. The present work was delineated to analyze the kinin B1 and B2 receptors expression in the hippocampus of patients presenting refractory mesial TLE. The hippocampi were removed during the patients surgery in a procedure used for seizure control and compared with tissues obtained after autopsy. Nissl staining was performed to study the tissue morphology and immunohistochemistry, and Western blot was used to compare the distribution and levels of both receptors in the hippocampus. In addition, real time PCR was employed to analyze the gene expression of these receptors. Nissl staining showed sclerotic hippocampi with hilar, granular, and pyramidal cell loss in TLE patients. Immunohistochemistry and Western blot analyses showed increased expression of kinin B1 and B2 receptors but the real-time PCR data demonstrated increased mRNA level only for kinin B2 receptors, when compared with controls. These data show for the first time a relationship between human TLE and the kallikrein-kinin system, confirming ours previous results, obtained from experimental models of epilepsy.

Role of viral infections in the etiology of febrile seizures

The role of viral infection in the etiology of febrile seizures is a relatively neglected field of neurologic research. A National Institutes of Health Consensus Conference (1981) omitted reference to causes of infections and the role of fever in febrile seizures, and emphasized outcome and anticonvulsant treatment. In an earlier review of the world literature (1924-1964), except for roseola infantum, viral infections as a cause of febrile seizures were rarely diagnosed. The present review includes reports of viruses most commonly associated with febrile seizures in the last decade, especially human herpesvirus-6 and influenza. The specificity and neurotropic properties of some viruses in the febrile seizure mechanism, a possible encephalitic or encephalopathic pathology, and the essential role of fever and height of the body temperature as a measure of the febrile seizure threshold are discussed. Cytokine and immune response to infection, and a genetic susceptibility to febrile seizures are additional etiologic factors. Future research should emphasize early detection of causative viruses, the nature of viral neurotropism, and the role of cytokines in fever induction. Trials of antiviral agents and vaccines, with attention to safety concerns, and more effective antipyretics would address the febrile seizure mechanism more specifically than anticonvulsant therapies.

Increased IL-1beta production from dsRNA-stimulated leukocytes in febrile seizures

This study examined the possibility that children with and without a history of febrile seizures might mount different immune responses to double-stranded ribonucleic acid, which is a common viral factor that induces host cell immune responses, and is recognized by Toll-like receptor 3. The production of interleukin-1beta and interferon-alpha from double-stranded ribonucleic acid-stimulated leukocytes was examined in 27 children (age 3.6+/-0.3 years) with a history of febrile seizures and in 18 children (age 3.4+/-0.2 years) without a history of febrile seizures. Significantly (P=0.0007) increased interleukin-1beta production was observed in children with a history of febrile seizures, compared with control subjects. When patients with a single prior episode of febrile seizures (n=9) and those with multiple prior episodes of febrile seizures (n=18) were compared, a significant difference in interleukin-1beta production was not observed. Genotyping of interleukin-1beta(-511), Toll-like receptor 3, Toll-IL-1 receptor domain-containing adapter inducing interferon-beta, and interleukin-1 receptor antagonist polymorphisms revealed no significant differences in allelic distribution among febrile seizure patients and control subjects. Interleukin-1beta production was not significantly influenced by genotype. Viral infection results in increased interleukin-1beta production in febrile seizure patients, and this may play a role in febrile seizures.

Interleukin-1 as a therapeutic target in acute brain injury

Interest in the interactions between the immune and central nervous systems has furthered our understanding of brain function in health and disease. Experimental and clinical studies increasingly reveal an inflammatory component in the pathophysiology of many forms of brain injury. Members of the interleukin (IL)-1 cytokine family are produced by diverse cell types within the brain and may determine the outcome of neuronal injury. This review discusses the neuroprotective potential of IL-1 inhibition in various acute neurological and neurosurgical diseases. The ILs comprise an expanding family of cytokines with diverse physiological and pathological actions, of which IL-1 is a key inflammatory mediator implicated in brain injury. IL-1 expression in the normal CNS is low, but is upregulated rapidly in response to brain injury. In experimental studies, IL-1 and its endogenous, competitive, selective antagonist, IL-1 receptor antagonist (IL-1RA), mediate neurotoxic and neuroprotective outcomes, respectively. Clinical studies support the relationship between inflammation, disease severity and poor prognosis in various neurological and neurosurgical disorders. Recombinant human (rh)IL-1RA shows modest blood–brain barrier penetrance and is safe for clinical use when administered parenterally. Evidence supporting the use of rhIL-1RA and other approaches to targeting IL-1 are discussed in relation to cerebral ischemia, seizures, subarachnoid hemorrhage and traumatic brain injury.