Annual review prize lecture cytokines - killers in the brain?

Free Bilirubin Induces Neuro-Inflammation in an Induced Pluripotent Stem Cell-Derived Cortical Organoid Model of Crigler-Najjar Syndrome

Bilirubin-induced neurological damage (BIND), which might progress to kernicterus, occurs as a consequence of defects in the bilirubin conjugation machinery, thus enabling albumin-unbound free bilirubin (BF) to cross the blood-brain barrier and accumulate within. A defect in the UGT1A1 enzyme-encoding gene, which is directly responsible for bilirubin conjugation, can cause Crigler-Najjar syndrome (CNS) and Gilbert's syndrome. We used human-induced pluripotent stem cell (hiPSC)-derived 3D brain organoids to model BIND in vitro and unveil the molecular basis of the detrimental effects of BF in the developing human brain. Healthy and patient-derived iPSCs were differentiated into day-20 brain organoids, and then stimulated with 200 nM BF. Analyses at 24 and 72 h post-treatment point to BF-induced neuro-inflammation in both cell lines. Transcriptome, associated KEGG, and Gene Ontology analyses unveiled the activation of distinct inflammatory pathways, such as cytokine-cytokine receptor interaction, MAPK signaling, and NFκB activation. Furthermore, the mRNA expression and secretome analysis confirmed an upregulation of pro-inflammatory cytokines such as IL-6 and IL-8 upon BF stimulation. This novel study has provided insights into how a human iPSC-derived 3D brain organoid model can serve as a prospective platform for studying the etiology of BIND kernicterus.

Biomarkers in Traumatic Brain Injuries: Narrative Review

Traumatic brain injury (TBI) is a multistep interaction of brain antigens, cytokine-mediated humeral, and cellular immune reactions. Because of the limitations of clinical and radiological evaluation in TBI, there has been a considerable advancement toward the need for developing biomarkers that can predict the severity of TBI. Blood-based brain biomarkers hold the potential to predict the absence of intracranial injury and thus decrease unnecessary brain computed tomographic scanning. Various biomarkers have been studied that detects neuronal, axonal, and blood–brain barrier integrity. Biomarkers are still under investigation and hold promise in the future evaluation of TBI patients. They can be used for grading as well as a prognostication of head injury.

Dietary Methionine via Dose-Dependent Inhibition of Short-Chain Fatty Acid Production Capacity Contributed to a Potential Risk of Cognitive Dysfunction in Mice

High-methionine diets induce impaired learning and memory function, dementia-like neurodegeneration, and Alzheimer's disease, while low-methionine diets improve learning and memory function. We speculated that variations in intestinal microbiota may mediate these diametrically opposed effects; thus, this study aimed to verify this hypothesis. The ICR mice were fed either a low-methionine diet (LM, 0.17% methionine), normal methionine diet (NM, 0.86% methionine), or high-methionine diet (HM, 2.58% methionine) for 11 weeks. We found that HM diets damaged nonspatial recognition memory, working memory, and hippocampus-dependent spatial memory and induced anxiety-like behaviors in mice. LM diets improved nonspatial recognition memory and hippocampus-dependent spatial memory and ameliorated anxiety-like behavior, but the differences did not reach a significant level. Moreover, HM diets significantly decreased the abundance of putative short-chain fatty acid (SCFA)-producing bacteria (Roseburia, Blautia, Faecalibaculum, and Bifidobacterium) and serotonin-producing bacteria (Turicibacter) and significantly increased the abundance of proinflammatory bacteria Escherichia-Shigella. Of note, LM diets reversed the results. Consequently, the SCFA and serotonin levels were significantly decreased with HM diets and significantly increased with LM diets. Furthermore, HM diets induced hippocampal oxidative stress and inflammation and selectively downregulated the hippocampus-dependent memory-related gene expression, whereas LM diets selectively upregulated the hippocampus-dependent memory-related gene expression. In conclusion, dietary methionine via dose-dependent inhibition of SCFA production capacity contributed to a potential risk of cognitive dysfunction in mice.

Effect of Renal Ischemia Reperfusion on Brain Neuroinflammation

Acute kidney injury (AKI) is an inflammatory sequence. It can lead to distant organ injury, including damage to the central nervous system (CNS), mediated by increased circulating cytokines and other inflammatory mediators. It can also lead to increased blood-brain barrier (BBB) permeability. However, the effect of AKI on the inflammatory response of the brain has not yet been investigated. Therefore, we observed the effect of AKI on BBB permeability, microglia and astrocyte activation, and neuronal toxicity in the brain. The striatum and ventral midbrain, known to control overall movement, secrete the neurotransmitter dopamine. The activation of microglia and astrocytes present in this area causes neuro-degenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). The activation of astrocytes and microglia in the hippocampus and cerebral cortex, which are responsible for important functions, including memory, learning, concentration, and language, can trigger nerve cell apoptosis. The activation of astrocytes and microglia at this site is also involved in the inflammatory response associated with the accumulation of beta-amyloid. In the situation of kidney ischemia reperfusion (IR)-induced AKI, activation of microglia and astrocytes were observed in the striatum, ventral midbrain, hippocampus, and cortex. However, neuronal cell death was not observed until 48 h.

A Dichotomous Role for FABP7 in Sleep and Alzheimer's Disease Pathogenesis: A Hypothesis

Fatty acid binding proteins (FABPs) are a family of intracellular lipid chaperone proteins known to play critical roles in the regulation of fatty acid uptake and transport as well as gene expression. Brain-type fatty acid binding protein (FABP7) is enriched in astrocytes and has been implicated in sleep/wake regulation and neurodegenerative diseases; however, the precise mechanisms underlying the role of FABP7 in these biological processes remain unclear. FABP7 binds to both arachidonic acid (AA) and docosahexaenoic acid (DHA), resulting in discrete physiological responses. Here, we propose a dichotomous role for FABP7 in which ligand type determines the subcellular translocation of fatty acids, either promoting wakefulness aligned with Alzheimer's pathogenesis or promoting sleep with concomitant activation of anti-inflammatory pathways and neuroprotection. We hypothesize that FABP7-mediated translocation of AA to the endoplasmic reticulum of astrocytes increases astrogliosis, impedes glutamatergic uptake, and enhances wakefulness and inflammatory pathways via COX-2 dependent generation of pro-inflammatory prostaglandins. Conversely, we propose that FABP7-mediated translocation of DHA to the nucleus stabilizes astrocyte-neuron lactate shuttle dynamics, preserves glutamatergic uptake, and promotes sleep by activating anti-inflammatory pathways through the peroxisome proliferator-activated receptor-γ transcriptional cascade. Importantly, this model generates several testable hypotheses applicable to other neurodegenerative diseases, including amyotrophic lateral sclerosis and Parkinson's disease.

Perspectives in the Cell-Based Therapies of Various Aspects of the Spinal Cord Injury-Associated Pathologies: Lessons from the Animal Models

Traumatic injury of the spinal cord (SCI) is a devastating neurological condition often leading to severe dysfunctions, therefore an improvement in clinical treatment for SCI patients is urgently needed. The potential benefits of transplantation of various cell types into the injured spinal cord have been intensively investigated in preclinical SCI models and clinical trials. Despite the many challenges that are still ahead, cell transplantation alone or in combination with other factors, such as artificial matrices, seems to be the most promising perspective. Here, we reviewed recent advances in cell-based experimental strategies supporting or restoring the function of the injured spinal cord with a particular focus on the regenerative mechanisms that could define their clinical translation.

Infection and Risk of Parkinson's Disease

Parkinson’s disease (PD) is thought to be caused by a combination of genetic and environmental factors. Bacterial or viral infection has been proposed as a potential risk factor, and there is supporting although not entirely consistent epidemiologic and basic science evidence to support its role. Encephalitis caused by influenza has included parkinsonian features. Epidemiological evidence is most compelling for an association between PD and hepatitis C virus. Infection with Helicobacter pylori may be associated not only with PD risk but also response to levodopa. Rapidly evolving knowledge regarding the role of the microbiome also suggests a role of resident bacteria in PD risk. Biological plausibility for the role for infectious agents is supported by the known neurotropic effects of specific viruses, particular vulnerability of the substantia nigra and even the promotion of aggregation of alpha-synuclein. A common feature of implicated viruses appears to be production of high levels of cytokines and chemokines that can cross the blood-brain barrier leading to microglial activation and inflammation and ultimately neuronal cell death. Based on multiple avenues of evidence it appears likely that specific bacterial and particularly viral infections may increase vulnerability to PD. The implications of this for PD prevention requires attention and may be most relevant once preventive treatments for at-risk populations are developed.

Revisiting Traumatic Brain Injury: From Molecular Mechanisms to Therapeutic Interventions

Studying the complex molecular mechanisms involved in traumatic brain injury (TBI) is crucial for developing new therapies for TBI. Current treatments for TBI are primarily focused on patient stabilization and symptom mitigation. However, the field lacks defined therapies to prevent cell death, oxidative stress, and inflammatory cascades which lead to chronic pathology. Little can be done to treat the mechanical damage that occurs during the primary insult of a TBI; however, secondary injury mechanisms, such as inflammation, blood-brain barrier (BBB) breakdown, edema formation, excitotoxicity, oxidative stress, and cell death, can be targeted by therapeutic interventions. Elucidating the many mechanisms underlying secondary injury and studying targets of neuroprotective therapeutic agents is critical for developing new treatments. Therefore, we present a review on the molecular events following TBI from inflammation to programmed cell death and discuss current research and the latest therapeutic strategies to help understand TBI-mediated secondary injury.

Inflammation-induced endothelial to mesenchymal transition promotes brain endothelial cell dysfunction and occurs during multiple sclerosis pathophysiology

The blood-brain barrier (BBB) has a major role in maintaining brain homeostasis through the specialized function of brain endothelial cells (BECs). Inflammation of the BECs and loss of their neuroprotective properties is associated with several neurological disorders, including the chronic neuro-inflammatory disorder multiple sclerosis (MS). Yet, the underlying mechanisms of a defective BBB in MS remain largely unknown. Endothelial to mesenchymal transition (EndoMT) is a pathophysiological process in which endothelial cells lose their specialized function and de-differentiate into mesenchymal cells. This transition is characterized by an increase in EndoMT-related transcription factors (TFs), a downregulation of brain endothelial markers, and an upregulation of mesenchymal markers accompanied by morphological changes associated with cytoskeleton reorganization. Here, we postulate that EndoMT drives BEC de-differentiation, mediates inflammation-induced human BECs dysfunction, and may play a role in MS pathophysiology. We provide evidence that stimulation of human BECs with transforming growth factor (TGF)-β1 and interleukin (IL)-1β promotes EndoMT, a process in which the TF SNAI1, a master regulator of EndoMT, plays a crucial role. We demonstrate the involvement of TGF-β activated kinase 1 (TAK1) in EndoMT induction in BECs. Finally, immunohistochemical analysis revealed EndoMT-associated alterations in the brain vasculature of human post-mortem MS brain tissues. Taken together, our novel findings provide a better understanding of the molecular mechanisms underlying BECs dysfunction during MS pathology and can be used to develop new potential therapeutic strategies to restore BBB function.

PKC delta activation increases neonatal rat retinal cells survival in vitro: Involvement of neurotrophins and M1 muscarinic receptors

Protein kinase C (PKC) is a family of serine/threonine kinases related to several phenomena as cell proliferation, differentiation and survival. Our previous data demonstrated that treatment of axotomized neonatal rat retinal cell cultures for 48 h with phorbol 12-myristate 13-acetate (PMA), a PKC activator, increases retinal ganglion cells (RGCs) survival. Moreover, this treatment decreases M1 receptors (M1R) and modulates BDNF levels. The aim of this work was to assess the possible involvement of neurotrophins BDNF and NGF in the modulation of M1R levels induced by PKC activation, and its involvement on RGCs survival. Our results show that PMA (50 ng/mL) treatment, via PKC delta activation, modulates NGF, BDNF and M1R levels. BDNF and NGF mediate the decrease of M1R levels induced by PMA treatment. M1R activation is essential to PMA neuroprotective effect on RGCs as telenzepine (M1R selective antagonist) abolished it. Based on our results we suggest that PKC delta activation modulates neurotrophins levels by a signaling pathway that involves M1R activation and ultimately leading to an increase in RGCs survival in vitro.

Increased serum levels and promoter polymorphisms of macrophage migration inhibitory factor in schizophrenia

BACKGROUND

Numerous studies have suggested that an immune system imbalance plays an important role in schizophrenia. Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine. It plays multiple roles in various biological processes, including inflammation and neurogenesis. Furthermore, several exhaustive serum proteomic profiling studies have identified MIF as a potential biomarker of schizophrenia. Here, we investigate MIF protein levels in serum and postmortem prefrontal cortex in patients with schizophrenia and controls. Moreover, we investigate the association of two functional polymorphisms in the MIF gene promoter region (MIF-794CATT_5-8 microsatellite and MIF-173G/C single-nucleotide polymorphism [SNP]) with schizophrenia.

METHODS

We measured serum MIF levels with an enzyme-linked immunosorbent assay (ELISA) (51 patients vs. 86 controls) and postmortem brain MIF levels with a western blotting assay (18 patients vs. 22 controls). Subsequently, we genotyped the MIF-794CATT_5-8 microsatellite with a fluorescence-based fragment assay and the MIF-173G/C SNP with a TaqMan SNP genotyping assay (1483 patients vs. 1454 controls).

RESULTS

Serum MIF levels were significantly higher in patients with schizophrenia than in controls (p=0.00118), and were positively correlated with antipsychotic dose (Spearman's r=0.222, p=0.0402). In addition, an earlier age of onset was observed in patients with a high serum MIF level (≥40ng/mL) than those with a low serum MIF level (<40ng/mL) (p=0.0392). However, postmortem brain MIF levels did not differ between patients with schizophrenia and controls. The association study revealed that the CATT₆-G haplotype was nominally significantly associated with schizophrenia (p=0.0338), and that the CATT₆ allele and CATT₆-G haplotype were significantly associated with female adolescent-onset schizophrenia (AsOS) (corrected p=0.0222 and p=0.0147, respectively).

CONCLUSIONS

These results suggest that serum MIF level is a potential pharmacodynamic and/or monitoring marker of schizophrenia, and is related to a novel antipsychotic effect beyond dopamine antagonism. Furthermore, the MIF gene polymorphisms are associated with the risk for schizophrenia especially in adolescent females, and are potential stratification markers of schizophrenia. Further studies of MIF are warranted to elucidate the pathophysiology of schizophrenia and the effects of antipsychotics.

Indomethacin counteracts the effects of chronic social defeat stress on emotional but not recognition memory in mice

We have previously observed the impairing effects of chronic social defeat stress (CSDS) on emotional memory in mice. Given the relation between stress and inflammatory processes, we sought to study the effectiveness of the anti-inflammatory indomethacin in reversing the detrimental effects of CSDS on emotional memory in mice. The effects of CSDS and indomethacin on recognition memory were also evaluated. Male CD1 mice were randomly divided into four groups: non-stressed + saline (NS+SAL); non-stressed + indomethacin (NS+IND); stressed + saline (S+SAL); and stressed + indomethacin (S+IND). Stressed animals were exposed to a daily 10 min agonistic confrontation (CSDS) for 20 days. All subjects were treated daily with saline or indomethacin (10 mg/kg, i.p.). 24 h after the CSDS period, all the mice were evaluated in a social interaction test to distinguish between those that were resilient or susceptible to social stress. All subjects (n = 10–12 per group) were then evaluated in inhibitory avoidance (IA), novel object recognition (NOR), elevated plus maze and hot plate tests. As in control animals (NS+SAL group), IA learning was observed in the resilient groups, as well as in the susceptible mice treated with indomethacin (S+IND group). Recognition memory was observed in the non-stressed and the resilient mice, but not in the susceptible animals. Also, stressed mice exhibited higher anxiety levels. No significant differences were observed in locomotor activity or analgesia. In conclusion, CSDS induces anxiety in post-pubertal mice and impairs emotional and recognition memory in the susceptible subjects. The effects of CSDS on emotional memory, but not on recognition memory and anxiety, are reversed by indomethacin. Moreover, memory impairment is not secondary to the effects of CSDS on locomotor activity, emotionality or pain sensitivity.

Neutralizing anti-interleukin-1β antibodies reduce ischemia-related interleukin-1β transport across the blood-brain barrier in fetal sheep

Hypoxic ischemic insults predispose to perinatal brain injury. Pro-inflammatory cytokines are important in the evolution of this injury. Interleukin-1β (IL-1β) is a key mediator of inflammatory responses and elevated IL-1β levels in brain correlate with adverse neurodevelopmental outcomes after brain injury. Impaired blood-brain barrier (BBB) function represents an important component of hypoxic-ischemic brain injury in the fetus. In addition, ischemia-reperfusion increases cytokine transport across the BBB of the ovine fetus. Reducing pro-inflammatory cytokine entry into brain could represent a novel approach to attenuate ischemia-related brain injury. We hypothesized that infusions of neutralizing IL-1β monoclonal antibody (mAb) reduce IL-1β transport across the BBB after ischemia in the fetus. Fetal sheep were studied 24-h after 30-min of carotid artery occlusion. Fetuses were treated with placebo- or anti-IL-1β mAb intravenously 15-min and 4-h after ischemia. Ovine IL-1β protein expressed from IL-1β pGEX-2T vectors in Escherichia coli (E. coli) BL-21 cells was produced, purified, and radiolabeled with ¹²⁵I. BBB permeability was quantified using the blood-to-brain transfer constant (K_i) with ¹²⁵I-radiolabeled-IL-1β. Increases in anti-IL-1β mAb were observed in the brain of the mAb-treated group (P<0.001). Blood-to-brain transport of ¹²⁵I-IL-1β was lower (P<0.04) across brain regions in the anti-IL-1β mAb-treated than placebo-treated ischemic fetuses. Plasma ¹²⁵I-IL-1β counts were higher (P<0.001) in the anti-IL-1β mAb- than placebo-treated ischemic fetuses. Systemic infusions of anti-IL-1β mAb reduce IL-1β transport across the BBB after ischemia in the ovine fetus. Our findings suggest that conditions associated with increases in systemic pro-inflammatory cytokines and neurodevelopmental impairment could benefit from an anti-cytokine therapeutic strategy.

Effects of Electroconvulsive Therapy on Some Inflammatory Factors in Patients With Treatment-Resistant Schizophrenia

OBJECTIVES

Electroconvulsive therapy (ECT) is the most effective option for several psychiatric conditions, including treatment-resistant schizophrenia. However, little is known about the molecular mechanism of action of ECT. The link between inflammatory system and schizophrenia is the focus of recent studies. However, the impact of ECT on inflammatory functioning in this disorder remains elusive. Whether ECT could modulate inflammatory factors in patients with schizophrenia was examined.

METHODS

Plasma levels of interleukin-4 (IL-4), transforming growth factor-β (TGF-β), myeloperoxidase (MPO), and nuclear factor-κB (NF-κB) activation were analyzed in 20 schizophrenic patients, mainly with resistant to antipsychotic medication disorders, and in 20 sex- and age-matched healthy controls. Disease severity was evaluated using the Brief Psychiatric Rating Scale. All patients were followed with measurement of the inflammatory factors before and after ECT treatment and compared with the controls.

RESULTS

Patients with schizophrenia had markedly raised NF-κB and but decreased TGF-β levels compared with healthy controls. On the other hand, no significant differences were found for the levels of IL-4 and MPO levels. The clinical improvement during repeated ECT was accompanied by a gradual and significant increase in IL-4 and TGF-β level, but MPO and NF-κB activation were left unaffected. Increases in TGF-β were negatively correlated with the change in Brief Psychiatric Rating Scale scores after ECT.

CONCLUSIONS

It is shown that ECT, while increasing the anti-inflammatory response such as the levels of IL-4 and TGF-β, it did not affect the levels of MPO and NF-κB activation in this study.

Diffuse traumatic axonal injury in mice induces complex behavioural alterations that are normalized by neutralization of interleukin-1β

Widespread traumatic axonal injury (TAI) results in brain network dysfunction, which commonly leads to persisting cognitive and behavioural impairments following traumatic brain injury (TBI). TBI induces a complex neuroinflammatory response, frequently located at sites of axonal pathology. The role of the pro-inflammatory cytokine interleukin (IL)-1β has not been established in TAI. An IL-1β-neutralizing or a control antibody was administered intraperitoneally at 30 min following central fluid percussion injury (cFPI), a mouse model of widespread TAI. Mice subjected to moderate cFPI (n = 41) were compared with sham-injured controls (n = 20) and untreated, naive mice (n = 9). The anti-IL-1β antibody reached the target brain regions in adequate therapeutic concentrations (up to ~30 μg/brain tissue) at 24 h post-injury in both cFPI (n = 5) and sham-injured (n = 3) mice, with lower concentrations at 72 h post-injury (up to ~18 μg/g brain tissue in three cFPI mice). Functional outcome was analysed with the multivariate concentric square field (MCSF) test at 2 and 9 days post-injury, and the Morris water maze (MWM) at 14-21 days post-injury. Following TAI, the IL-1β-neutralizing antibody resulted in an improved behavioural outcome, including normalized behavioural profiles in the MCSF test. The performance in the MWM probe (memory) trial was improved, although not in the learning trials. The IL-1β-neutralizing treatment did not influence cerebral ventricle size or the number of microglia/macrophages. These findings support the hypothesis that IL-1β is an important contributor to the processes causing complex cognitive and behavioural disturbances following TAI.

Therapies negating neuroinflammation after brain trauma

Traumatic brain injury (TBI) elicits a complex secondary injury response, with neuroinflammation as a crucial central component. Long thought to be solely a deleterious factor, the neuroinflammatory response has recently been shown to be far more intricate, with both beneficial and detrimental consequences depending on the timing, magnitude and specific immune composition of the response post-injury. Despite extensive preclinical and clinical research into mechanisms of secondary injury after TBI, no effective neuroprotective therapy has been identified, with potential candidates repeatedly proving disappointing in the clinic. The neuroinflammatory response offers a promising avenue for therapeutic targeting, aiming to quell the deleterious consequences without influencing its function in providing a neurotrophic environment supportive of repair. The present review firstly describes the findings of recent clinical trials that aimed to modulate inflammation as a means of neuroprotection. Secondly, we discuss promising multifunctional and single-target anti-inflammatory candidates either currently in trial, or with ample experimental evidence supporting clinical application. This article is part of a Special Issue entitled SI:Brain injury and recovery.

A Review of the Effectiveness of Neuroimaging Modalities for the Detection of Traumatic Brain Injury

The incidence of traumatic brain injury (TBI) in the United States was 3.5 million cases in 2009, according to the Centers for Disease Control and Prevention. It is a contributing factor in 30.5% of injury-related deaths among civilians. Additionally, since 2000, more than 260,000 service members were diagnosed with TBI, with the vast majority classified as mild or concussive (76%). The objective assessment of TBI via imaging is a critical research gap, both in the military and civilian communities. In 2011, the Department of Defense (DoD) prepared a congressional report summarizing the effectiveness of seven neuroimaging modalities (computed tomography [CT], magnetic resonance imaging [MRI], transcranial Doppler [TCD], positron emission tomography, single photon emission computed tomography, electrophysiologic techniques [magnetoencephalography and electroencephalography], and functional near-infrared spectroscopy) to assess the spectrum of TBI from concussion to coma. For this report, neuroimaging experts identified the most relevant peer-reviewed publications and assessed the quality of the literature for each of these imaging technique in the clinical and research settings. Although CT, MRI, and TCD were determined to be the most useful modalities in the clinical setting, no single imaging modality proved sufficient for all patients due to the heterogeneity of TBI. All imaging modalities reviewed demonstrated the potential to emerge as part of future clinical care. This paper describes and updates the results of the DoD report and also expands on the use of angiography in patients with TBI.

Rapamycin protects neurons from brain contusion‑induced inflammatory reaction via modulation of microglial activation

The inflammatory reaction is important in secondary injury following traumatic brain injury (TBI). Rapamycin has been demonstrated as a neuroprotective agent in a mouse model of TBI, however, there is a lack of data regarding the effects of rapamycin on the inflammatory reaction following TBI. Therefore, the present study was designed to assess the effects of treatment with rapamycin on inflammatory reactions and examine the possible involvement of microglial activation following TBI. Male imprinting control region mice were randomly divided into four groups: Sham group (n=23), TBI group (n=23), TBI + dimethyl sulfoxide (DMSO) group (n=31) and TBI + rapamycin group (n=31). Rapamycin was dissolved in DMSO (50 mg/ml) and injected 30 min after TBI (2 mg/Kg; intraperitoneally). A weight-drop model of TBI was induced, and the brain tissues were harvested 24 h after TBI. The findings indicated that the administration of rapamycin following TBI was associated with decreased levels of activated microglia and neuron degeneration at the peri-injury site, reduced levels of proinflammatory cytokines and increased neurobehavioral function, possibly mediated by inactivation of the mammalian target of rapamycin pathway. The results of the present study offer novel insight into the mechanisms responsible for the anti-neuroinflammatory effects of rapamycin, possibly involving the modulation of microglial activation.

Effects of an interleukin-1 receptor antagonist on human sleep, sleep-associated memory consolidation, and blood monocytes

Pro-inflammatory cytokines like interleukin-1 beta (IL-1) are major players in the interaction between the immune system and the central nervous system. Various animal studies report a sleep-promoting effect of IL-1 leading to enhanced slow wave sleep (SWS). Moreover, this cytokine was shown to affect hippocampus-dependent memory. However, the role of IL-1 in human sleep and memory is not yet understood. We administered the synthetic IL-1 receptor antagonist anakinra (IL-1ra) in healthy humans (100mg, subcutaneously, before sleep; n=16) to investigate the role of IL-1 signaling in sleep regulation and sleep-dependent declarative memory consolidation. Inasmuch monocytes have been considered a model for central nervous microglia, we monitored cytokine production in classical and non-classical blood monocytes to gain clues about how central nervous effects of IL-1ra are conveyed. Contrary to our expectation, IL-1ra increased EEG slow wave activity during SWS and non-rapid eye movement (NonREM) sleep, indicating a deepening of sleep, while sleep-associated memory consolidation remained unchanged. Moreover, IL-1ra slightly increased prolactin and reduced cortisol levels during sleep. Production of IL-1 by classical monocytes was diminished after IL-1ra. The discrepancy to findings in animal studies might reflect species differences and underlines the importance of studying cytokine effects in humans.

Subtypes of post-traumatic epilepsy: clinical, electrophysiological, and imaging features

Post-traumatic epilepsy (PTE) is a consequence of traumatic brain injury (TBI), occurring in 10-25% of patients with moderate to severe injuries. The development of animal models for testing antiepileptogenic therapies and validation of biomarkers to follow epileptogenesis in humans necessitates sophisticated understanding of the subtypes of PTE, which is the objective of this study. In this study, retrospective review was performed of patients with moderate to severe TBI with subsequent development of medically refractory epilepsy referred for video-electroencephalography (EEG) monitoring at a single center over a 10-year period. Information regarding details of injury, neuroimaging studies, seizures, video-EEG, and surgery outcomes were collected and analyzed. There were 123 patients with PTE identified, representing 4.3% of all patients evaluated in the epilepsy monitoring unit. Most of them had localization-related epilepsy, of which 57% had temporal lobe epilepsy (TLE), 35% had frontal lobe epilepsy (FLE), and 3% each had parietal and occipital lobe epilepsy. Of patients with TLE, 44% had mesial temporal sclerosis (MTS), 26% had temporal neocortical lesions, and 30% were nonlesional. There was no difference in age at injury between the different PTE subtypes. Twenty-two patients, 13 of whom had MTS, proceeded to surgical resection. At a mean follow-up of 2.5 years, Engel Class I outcomes were seen in 69% of those with TLE and 33% of those with FLE. Our findings suggest PTE is a heterogeneous condition, and careful evaluation with video-EEG monitoring and high resolution MRI can identify distinct syndromes. These results have implications for the design of clinical trials of antiepileptogenic therapies for PTE.

The role of inflammasome in Alzheimer's disease

Alzheimer's disease (AD) is a chronic, progressive and irreversible neurodegenerative disease with clinical characteristics of memory loss, dementia and cognitive impairment. Although the pathophysiologic mechanism is not fully understood, inflammation has been shown to play a critical role in the pathogenesis of AD. Inflammation in the central nervous system (CNS) is characterized by the activation of glial cells and release of proinflammatory cytokines and chemokines. Accumulating evidence demonstrates that inflammasomes, which cleave precursors of interleukin-1β (IL-1β) and IL-18 to generate their active forms, play an important role in the inflammatory response in the CNS and in AD pathogenesis. Therefore, modulating inflammasome complex assembly and activation could be a potential strategy for suppressing inflammation in the CNS. This review aims to provide insight into the role of inflammasomes in the CNS, with respect to the pathogenesis of AD, and may provide possible clues for devising novel therapeutic strategies.

Association analysis of putative cis-acting polymorphisms of interleukin-19 gene with schizophrenia

BACKGROUND

Genome-wide association studies (GWAS) and gene expression analyses have revealed that single nucleotide polymorphisms (SNPs) associated with multifactorial diseases, such as schizophrenia, are significantly more likely to be associated with expression quantitative trait loci (eQTL). It was recently suggested that an immune system imbalance plays an important role in the pathogenesis of schizophrenia. Interleukin-19 is a novel cytokine that may play multiple roles in immune regulation and various diseases.

METHOD

We selected eight tag SNPs in the eQTL of the IL-19 gene. Seven of the SNPs are putative cis-acting SNPs. Then, we conducted a case-control study using two independent samples. The first sample comprised 567 schizophrenia patients and 710 controls, and the second sample comprised 677 schizophrenia patients and 667 controls.

RESULT

We identified the TGAA haplotype as being significantly associated with schizophrenia (p=0.0036 and corrected p=0.0264), although a combined analysis of the TGAA haplotype with the replication samples exhibited a nominally significant difference (p=0.022 and corrected p=0.235).

CONCLUSIONS

These results suggest that the IL-19 gene might slightly contribute to the genetic risk of schizophrenia. Thus, further research on the association of eQTL SNPs with schizophrenia is warranted.

Long-term functional consequences and ongoing cerebral inflammation after subarachnoid hemorrhage in the rat

Subarachnoid hemorrhage (SAH) represents a considerable health problem with an incidence of 6–7 per 100.000 individuals per year in Western society. We investigated the long-term consequences of SAH on behavior, neuroinflammation and gray- and white-matter damage using an endovascular puncture model in Wistar rats. Rats were divided into a mild or severe SAH group based on their acute neurological score at 24 h post-SAH. The degree of hemorrhage determined in post-mortem brains at 48 h strongly correlated with the acute neurological score. Severe SAH induced increased TNF-α, IL-1β, IL-10, MCP-1, MIP2, CINC-1 mRNA expression and cortical neutrophil influx at 48 h post-insult. Neuroinflammation after SAH was very long-lasting and still present at day 21 as determined by Iba-1 staining (microglia/macrophages) and GFAP (astrocytes). Long-term neuroinflammation was strongly associated with the degree of severity of SAH. Cerebral damage to gray- and white-matter was visualized by immunohistochemistry for MAP2 and MBP at 21 days after SAH. Severe SAH induced significant gray- and white-matter damage. MAP2 loss at day 21 correlated significantly with the acute neurological score determined at 24 h post-SAH. Sensorimotor behavior, determined by the adhesive removal task and von Frey test, was affected after severe SAH at day 21. In conclusion, we are the first to show that SAH induces ongoing cortical inflammation. Moreover, SAH induces mainly cortical long-term brain damage, which is associated with long-term sensorimotor damage.

Pathogenesis of acute stroke and the role of inflammasomes

Inflammation is an innate immune response to infection or tissue damage that is designed to limit harm to the host, but contributes significantly to ischemic brain injury following stroke. The inflammatory response is initiated by the detection of acute damage via extracellular and intracellular pattern recognition receptors, which respond to conserved microbial structures, termed pathogen-associated molecular patterns or host-derived danger signals termed damage-associated molecular patterns. Multi-protein complexes known as inflammasomes (e.g. containing NLRP1, NLRP2, NLRP3, NLRP6, NLRP7, NLRP12, NLRC4, AIM2 and/or Pyrin), then process these signals to trigger an effector response. Briefly, signaling through NLRP1 and NLRP3 inflammasomes produces cleaved caspase-1, which cleaves both pro-IL-1β and pro-IL-18 into their biologically active mature pro-inflammatory cytokines that are released into the extracellular environment. This review will describe the molecular structure, cellular signaling pathways and current evidence for inflammasome activation following cerebral ischemia, and the potential for future treatments for stroke that may involve targeting inflammasome formation or its products in the ischemic brain.

New perspectives on central and peripheral immune responses to acute traumatic brain injury

Traumatic injury to the brain (TBI) results in a complex set of responses involving various symptoms and long-term consequences. TBI of any form can cause cognitive, behavioral and immunologic changes in later life, which underscores the problem of underdiagnosis of mild TBI that can cause long-term neurological deficits. TBI disrupts the blood–brain barrier (BBB) leading to infiltration of immune cells into the brain and subsequent inflammation and neurodegeneration. TBI-induced peripheral immune responses can also result in multiorgan damage. Despite worldwide research efforts, the methods of diagnosis, monitoring and treatment for TBI are still relatively ineffective. In this review, we delve into the mechanism of how TBI-induced central and peripheral immune responses affect the disease outcome and discuss recent developments in the continuing effort to combat the consequences of TBI and new ways to enhance repair of the damaged brain.

Rapamycin preconditioning attenuates transient focal cerebral ischemia/reperfusion injury in mice

Rapamycin, an mTOR inhibitor and immunosuppressive agent in clinic, has protective effects on traumatic brain injury and neurodegenerative diseases. But, its effects on transient focal ischemia/reperfusion disease are not very clear. In this study, we examined the effects of rapamycin preconditioning on mice treated with middle cerebral artery occlusion/reperfusion operation (MCAO/R). We found that the rapamycin preconditioning by intrahippocampal injection 20 hr before MCAO/R significantly improved the survival rate and longevity of mice. It also decreased the neurological deficit score, infracted areas and brain edema. In addition, rapamycin preconditioning decreased the production of NF-κB, TNF-α, and Bax, but not Bcl-2, an antiapoptotic protein in the ischemic area. From these results, we may conclude that rapamycin preconditioning attenuate transient focal cerebral ischemia/reperfusion injury and inhibits apoptosis induced by MCAO/R in mice.

Haplotypes in the expression quantitative trait locus of interleukin-1β gene are associated with schizophrenia

Recent genome-wide association study (GWAS) and gene expression analyses have revealed that single nucleotide polymorphisms (SNPs) associated with complex diseases such as schizophrenia are significantly more likely to be associated with expression quantitative trait loci (eQTL). The interleukin-1β (IL1B) gene has been strongly implicated in the susceptibility to schizophrenia. In order to test this association, we selected five tag SNPs in the eQTL of the IL1B gene and conducted a case-control study using two independent samples. The first sample comprised 528 schizophrenic patients and 709 controls and the second sample comprised 576 schizophrenic patients and 768 controls. We identified two SNPs and several haplotypes as being significantly associated with schizophrenia. Previous reports indicated that one major haplotype that was protective against schizophrenia reduced IL1B transcription, while two risk haplotypes for schizophrenia enhanced IL1B transcription. Therefore, we measured IL1B mRNA expression in PAXgene-stabilized whole blood from 40 schizophrenic patients and 40 controls to explore the possibility of using five tag SNPs as schizophrenic trait markers. A multiple regression analysis taking confounding factors into account revealed that the T allele of rs4848306 SNP, which is a protective allele for schizophrenia, predicted reduced change in IL1B mRNA expression, regardless of phenotype. Our results appear to support the previous hypothesis that IL1B contributes to the genetic risk of schizophrenia and warrant further research on the association of eQTL SNPs with schizophrenia.

In-vitro validation of cytokine neutralizing antibodies by testing with ovine mononuclear splenocytes

Cytokines have gained increasing attention as therapeutic targets in inflammation-related disorders and inflammatory conditions have been investigated in sheep. Monoclonal antibodies (mAbs) specific for the ovine pro-inflammatory cytokines interleukin (IL)-1β and IL-6 could be used to study the effects of blocking pro-inflammatory cytokines in sheep. Ovine-specific IL-1β and IL-6 proteins and mAbs specific for these molecules were produced and the ability of the mAbs to neutralize the proteins was tested in cultures of ovine splenic mononuclear cells. Expression of nuclear factor (NF)-κβ and signal transducer and activator of transcription (STAT)-3 was evaluated by western blotting and densitometric quantification. Treatment with purified IL-1β and IL-6 proteins increased NF-κβ (P < 0.001) and STAT-3 (P < 0.01) expression, respectively, in cell culture. Treatment with these proteins that were pre-incubated with IL-1β and IL-6 mAbs attenuated (P < 0.01) these effects. These results confirm the bioactivity of ovine IL-1β and IL-6 proteins and the neutralizing capacity of anti-ovine-IL-1β and -IL-6 mAbs in vitro. These mAbs could be used to investigate anti-inflammatory strategies for attenuation of the effects of these pro-inflammatory cytokines in sheep.

Indomethacin protects rats from neuronal damage induced by traumatic brain injury and suppresses hippocampal IL-1β release through the inhibition of Nogo-A expression

BACKGROUND

Nogo-A is a member of the reticulon family of membrane-associated proteins and plays an important role in axonal remodeling. The present study aimed to investigate alterations in Nogo-A expression following traumatic brain injury (TBI)-induced inflammation and neuronal damage.

METHODS

A weight-drop device was used to deliver a standard traumatic impact to rats. Western blot, RT-PCR and ELISA were used to analyze the expression of Nogo-A and IL-1β. Nogo-A antisense, and an irrelevant control oligonucleotide was intracerebroventricularly infused. We also performed H & E staining and luxol fast blue staining to evaluate the neuronal damage and demyelination resulting from TBI and various treatments.

RESULTS

Based on RT-PCR and western blot analyses, the expression of Nogo-A was found to be significantly upregulated in the hippocampus beginning eight hours after TBI. In addition, TBI caused an apparent elevation in IL-1β levels and severe neuronal damage and demyelination in the tested animals. All of the TBI-associated molecular and cellular consequences could be effectively reversed by treating the animals with the anti-inflammatory drug indomethacin. More importantly, the TBI-associated stimulation in the levels of both Nogo-A and IL-1β could be effectively inhibited by a specific Nogo-A antisense oligonucleotide.

CONCLUSIONS

Our findings suggest that the suppression of Nogo-A expression appears to be an early response conferred by indomethacin, which then leads to decreases in the levels of IL-1β and TBI-induced neuron damage.

Guilty molecules, guilty minds? The conflicting roles of the innate immune response to traumatic brain injury

Traumatic brain injury (TBI) is a complex disease in the most complex organ of the body, whose victims endure lifelong debilitating physical, emotional, and psychosocial consequences. Despite advances in clinical care, there is no effective neuroprotective therapy for TBI, with almost every compound showing promise experimentally having disappointing results in the clinic. The complex and highly interrelated innate immune responses govern both the beneficial and deleterious molecular consequences of TBI and are present as an attractive therapeutic target. This paper discusses the positive, negative, and often conflicting roles of the innate immune response to TBI in both an experimental and clinical settings and highlights recent advances in the search for therapeutic candidates for the treatment of TBI.

Mechanisms and consequences of acquired brain injury during development

The brain of the infant and young child is a developing, dynamic, structure subject to functional remodelling under the influence of factors responsible for optimal neuronal development and synaptogenesis. It exhibits age dependent variation in metabolic rate, blood flow, and ability to tolerate oxidative stress. It is also characterized by an exuberance of neurotransmitter activity, particularly in the first few years of life. The dynamic evolution and adaptability of early brain function permits the organization of neuronal networks to be influenced by environmental stimulation, and, to reduce the functional impact of injury. However, these same processes may also exacerbate the harm sustained by the brain following an acquired brain injury (ABI). The developing neurons are susceptible to excitotoxicity, oxidative stress, and, inflammation, often leading to cellular necrosis and apoptosis. Despite being immunologically privileged via the blood brain barrier, the developing brain is susceptible to injury from systemic inflammation through alteration of normally protective cerebrovascular endothelial cell function. Finally, many of the therapeutic agents currently employed in post-ABI hospital care may also compromise ABI outcome via non-intended pharmacological effects. These agents include analgesic, sedative and anti-convulsant medications. This review emphasizes those physiological considerations in the developing brain which may impact the outcome after ABI, including, the cellular mechanisms of neuronal and cerebrovascular endothelial cell injury, ABI outcome and future therapeutic directions.

Neuroprotection by mefenamic acid against D-serine: involvement of oxidative stress, inflammation and apoptosis

Mefenamic acid, a non-steroidal antiinflammatory drug (NSAID), directly and dose-dependently exhibits neuroprotective activity. In our study, we investigated the effects of mefenamic acid against d-serine on oxidative stress in the hippocampus, cortex and cerebellum of rats. Furthermore, the potential inflammatory and apoptotic effects of d-serine and potential protective effect of mefenamic acid were determined at mRNA and protein levels of TNF-α, IL-1β, Bcl-2 and Bax. We found that d-serine significantly increased oxidative stress, levels of inflammation- and apoptosis-related molecules in a region specific manner. Mefenamic acid treatment provided significant protection against the elevation of lipid peroxidation, protein oxidation, levels of TNF-α, IL-1β and Bax. As a conclusion, we suggest that d-serine, as a potential neurodegenerative agent, may have a pivotal role in the regulation of oxidative stress, inflammation and apoptosis; and NSAIDs, such as mefenamic acid, may assist other therapeutics in treating disorders where d-serine-induced neurotoxic mechanisms are involved in.

Saturated long-chain fatty acids activate inflammatory signaling in astrocytes

This study describes the effects of long-chain fatty acids on inflammatory signaling in cultured astrocytes. Data show that the saturated fatty acid palmitic acid, as well as lauric acid and stearic acid, trigger the release of TNFα and IL-6 from astrocytes. Unsaturated fatty acids were unable to induce cytokine release from cultured astrocytes. Furthermore, the effects of palmitic acid on cytokine release require Toll-like receptor 4 rather than CD36 or Toll-like receptor 2, and do not depend on palmitic acid metabolism to palmitoyl-CoA. Inhibitor studies revealed that pharmacologic inhibition of p38 or p42/44 MAPK pathways prevents the pro-inflammatory effects of palmitic acid, whereas JNK and PI3K inhibition does not affect cytokine release. Depletion of microglia from primary astrocyte cultures using the lysosomotropic agent l-leucine methyl ester revealed that the ability of palmitic acid to trigger cytokine release is not dependent on the presence of microglia. Finally, data show that the essential ω-3 fatty acid docosahexaenoic acid acts in a dose-dependent manner to prevent the actions of palmitic acid on inflammatory signaling in astrocytes. Collectively, these data demonstrate the ability of saturated fatty acids to induce astrocyte inflammation in vitro. These data thus raise the possibility that high levels of circulating saturated fatty acids could cause reactive gliosis and brain inflammation in vivo, and could potentially participate in the reported adverse neurologic consequences of obesity and metabolic syndrome.

Oxygen resuscitation after hypoxia ischemia stimulates prostaglandin pathway in rat cortex

Exposure to hypoxia and hyperoxia in a rodent model of perinatal ischemia results in delayed cell death and inflammation. Hyperoxia increases oxidative stress that can trigger inflammatory cascades, neutrophil activation, and brain microvascular injury. Here we show that 100% oxygen resuscitation in our rodent model of perinatal ischemia increases cortical COX-2 protein levels, S-nitrosylated COX-2cys526, PGE2, iNOS and 5-LOX, all components of the prostaglandin and leukotriene inflammatory pathway.

The association of genetic variants in interleukin-1 genes with cognition: findings from the cardiovascular health study

The inflammatory cytokine interleukin-1 (IL1) potentially plays a role in cognitive deterioration through pathology due to a dementing disorder or due to an aging process. Study of genetic variants in the IL1 genes has been mostly limited to diseases such as Alzheimer's, however, there may be benefit to studying a continuous measure of cognition. Using data from the Cardiovascular Health Study, we evaluate genetic variation in the genes encoding inflammatory agonists IL1A and IL1B, and the antagonist IL1RN, with repeated measures of global cognition (3MS) and processing speed (DSST), using mixed effects models. We found statistically significant minor allele SNP associations with baseline performance on the 3MS in the IL1RN gene for Caucasians (rs17042917: beta=0.47, 95%CI=0.09, 0.85, p=0.016; rs4251961: beta=-0.36, 95%CI=-0.13,-0.60, p=0.0027; rs931471: beta=0.39, 95%CI=0.13, 0.65, p=0.0032), and the IL1B gene for African Americans (rs1143627: beta=1.6, 95%CI=0.48, 2.8; p=0.006 and rs1143634: beta=2.09, 95%CI=0.39, 3.8; p=0.016). Associations appear to be weaker in a subgroup with higher education level. Upon removing those diagnosed with dementia, effect sizes and statistical significance attenuated. These results provide supporting evidence that genetic variants in IL1 genes may be involved in inflammatory-related lowered cognition, that higher education may modify genetic predisposition, and that these associations may be driven by a dementia process.

Administration of simvastatin after kainic acid-induced status epilepticus restrains chronic temporal lobe epilepsy

In this study, we examined the effect of chronic administration of simvastatin immediately after status epilepticus (SE) on rat brain with temporal lobe epilepsy (TLE). First, we evaluated cytokines expression at 3 days post KA-lesion in hippocampus and found that simvastatin-treatment suppressed lesion-induced expression of interleukin (IL)-1β and tumor necrosis factor-α (TNF-α). Further, we quantified reactive astrocytosis using glial fibrillary acidic protein (GFAP) staining and neuron loss using Nissl staining in hippocampus at 4-6 months after KA-lesion. We found that simvastatin suppressed reactive astrocytosis demonstrated by a significant decrease in GFAP-positive cells, and attenuated loss of pyramidal neurons in CA3 and interneurons in dentate hilar (DH). We next assessed aberrant mossy fiber sprouting (MFS) that is known to contribute to recurrence of spontaneous seizure in epileptic brain. In contrast to the robust MFS observed in saline-treated animals, the extent of MFS was restrained by simvastatin in epileptic rats. Attenuated MFS was related to decreased neuronal loss in CA3 and DH, which is possibly a mechanism underlying decreased hippocampal susceptibility in animal treated with simvastatin. Electronic encephalography (EEG) was recorded during 4 to 6 months after KA-lesion. The frequency of abnormal spikes in rats with simvastatin-treatment decreased significantly compared to the saline group. In summary, simvastatin treatment suppressed cytokines expression and reactive astrocytosis and decreased the frequency of discharges of epileptic brain, which might be due to the inhibition of MFS in DH. Our study suggests that simvastatin administration might be a possible intervention and promising strategy for preventing SE exacerbating to chronic epilepsy.

Volume of white matter hyperintensities in healthy adults: contribution of age, vascular risk factors, and inflammation-related genetic variants

Aging is associated with appearance of white matter hyperintensities (WMH) on MRI scans. Vascular risk and inflammation, which increase with age, may contribute to white matter deterioration and proliferation of WMH. We investigated whether circulating biomarkers and genetic variants associated with elevated vascular risk and inflammation are associated with WMH volume in healthy adults (144 volunteers, 44-77 years of age). We examined association of WMH volume with age, sex, hypertension, circulating levels of total plasma homocysteine (tHcy), cholesterol (low-density lipoprotein), and C-reactive protein (CRP), and four polymorphisms related to vascular risk and inflammation: Apolipoprotein ε (ApoE ε2,3,4), Angiotensin-Converting Enzyme insertion/deletion (ACE I/D), methylenetetrahydrofolate reductase (MTHFR) C677T, C-reactive protein (CRP)-286C>A>T, and interleukin-1β (IL-1β) C-511T. We found that larger WMH volume was associated with advanced age, hypertension, and elevated levels of homocysteine and CRP but not with low-density lipoprotein levels. Homozygotes for IL-1β-511T allele and carriers of CRP-286T allele that are associated with increased inflammatory response had larger WMH than the other allelic combinations. Carriers of the APOE ε2 allele had larger frontal WMH than ε3 homozygotes and ε4 carriers did. Thus, in healthy adults, who are free of neurological and vascular disease, genetic variants that promote inflammation and elevated levels of vascular risk biomarkers can contribute to brain abnormalities. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.

Increased neuroinflammatory and arachidonic acid cascade markers, and reduced synaptic proteins, in brain of HIV-1 transgenic rats

Background

Cognitive impairment has been reported in human immune deficiency virus-1- (HIV-1-) infected patients as well as in HIV-1 transgenic (Tg) rats. This impairment has been linked to neuroinflammation, disturbed brain arachidonic acid (AA) metabolism, and synapto-dendritic injury. We recently reported upregulated brain AA metabolism in 7- to 9-month-old HIV-1 Tg rats. We hypothesized that these HIV-1 Tg rats also would show upregulated brain inflammatory and AA cascade markers and a deficit of synaptic proteins.

Methods

We measured protein and mRNA levels of markers of neuroinflammation and the AA cascade, as well as pro-apoptotic factors and synaptic proteins, in brains from 7- to 9-month-old HIV-1 Tg and control rats.

Results

Compared with control brain, HIV-1 Tg rat brain showed immunoreactivity to glycoprotein 120 and tat HIV-1 viral proteins, and significantly higher protein and mRNA levels of (1) the inflammatory cytokines interleukin-1β and tumor necrosis factor α, (2) the activated microglial/macrophage marker CD11b, (3) AA cascade enzymes: AA-selective Ca²⁺-dependent cytosolic phospholipase A₂ (cPLA₂)-IVA, secretory sPLA₂-IIA, cyclooxygenase (COX)-2, membrane prostaglandin E₂ synthase, 5-lipoxygenase (LOX) and 15-LOX, cytochrome p450 epoxygenase, and (4) transcription factor NF-κBp50 DNA binding activity. HIV-1 Tg rat brain also exhibited signs of cell injury, including significantly decreased levels of brain-derived neurotrophic factor (BDNF) and drebrin, a marker of post-synaptic excitatory dendritic spines. Expression of Ca²⁺-independent iPLA₂-VIA and COX-1 was unchanged.

Conclusions

HIV-1 Tg rats show elevated brain markers of neuroinflammation and AA metabolism, with a deficit in several synaptic proteins. These changes are associated with viral proteins and may contribute to cognitive impairment. The HIV-1 Tg rat may be a useful model for understanding progression and treatment of cognitive impairment in HIV-1 patients.

Aberrant immune responses in a mouse with behavioral disorders

BTBR T+tf/J (BTBR) mice have recently been reported to have behaviors that resemble those of autistic individuals, in that this strain has impairments in social interactions and a restricted repetitive and stereotyped pattern of behaviors. Since immune responses, including autoimmune responses, are known to affect behavior, and individuals with autism have aberrant immune activities, we evaluated the immune system of BTBR mice, and compared their immunity and degree of neuroinflammation with that of C57BL/6 (B6) mice, a highly social control strain, and with F1 offspring. Mice were assessed at postnatal day (pnd) 21 and after behavioral analysis at pnd70. BTBR mice had significantly higher amounts of serum IgG and IgE, of IgG anti-brain antibodies (Abs), and of IgG and IgE deposited in the brain, elevated expression of cytokines, especially IL-33 IL-18, and IL-1β in the brain, and an increased proportion of MHC class II-expressing microglia compared to B6 mice. The F1 mice had intermediate levels of Abs and cytokines as well as social activity. The high Ab levels of BTBR mice are in agreement with their increased numbers of CD40(hi)/I-A(hi) B cells and IgG-secreting B cells. Upon immunization with KLH, the BTBR mice produced 2-3 times more anti-KLH Abs than B6 mice. In contrast to humoral immunity, BTBR mice are significantly more susceptible to listeriosis than B6 or BALB/c mice. The Th2-like immune profile of the BTBR mice and their constitutive neuroinflammation suggests that an autoimmune profile is implicated in their aberrant behaviors, as has been suggested for some humans with autism.

Temporal and sequential changes of glial cells and cytokine expression during neuronal degeneration after transient global ischemia in rats

Background

How glial cells and cytokines are associated with the progression of delayed neuronal death induced by transient global ischemia is still unclear. To further clarify this point, we studied morphological changes in glial cells (microglial cells and astrocytes), and cytokine protein levels, during the progression of neuronal cell loss in CA1 (Cornu Ammonis 1) of the hippocampus after transient global ischemia.

Methods

Morphological changes in glial cells were studied immuno-histochemically. Nine cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-γ and TNF-α) were simultaneously measured by a multiplexed bead-based immunoassay from 6 h to day21 after transient four vessel occlusion (4VO) in rats.

Results

During the process of neuronal loss, we observed four distinct phases: (1) lag phase day0-2 (no NeuN+ cell loss observed), (2) exponential phase day2-7 (NeuN+ cells reduced in number exponentially), (3) deceleration phase day7-14 (reduction rate of NeuN+ cells became low), (4) stationary phase day14 onward (NeuN+ cell loss progressed no longer). In the lag phase, activated glial cells were observed in the entire hippocampus but later were gradually restricted to CA1. Cytokine protein levels in the lag and exponential phases were lower than in the deceleration and stationary phases. IL-1α, IL-1β, IL-4, IL-6 and IFN-γ in 4VO were significantly higher in all four phases than in sham. Compared with sham level, GM-CSF was significantly high in the deceleration phase. TNF-α was significantly high in both the deceleration and stationary phases.

Conclusion

Ischemic stress in 4VO activated glial cells in areas beyond CA1 in the lag phase. Pyramidal neurons were injured in CA1 from the end of the lag phase and then neuronal cells reduced in CA1 in the exponential phase. After neuronal death began, the influence of dead cells on glial cells and cytokine expression gradually became stronger than the influence by ischemic stress. Therefore, from the deceleration phase, changes in glial cells and cytokine production were likely caused by dead cells. Cytokine interaction in the microenvironment may determine the functions of IL-1α, IL-1β, IL-4, IL-6 and IFN-γ in all four phases. The function of GM-CSF and TNF-α in the deceleration phase may be neurotrophic.

Neutralization of interleukin-1β reduces cerebral edema and tissue loss and improves late cognitive outcome following traumatic brain injury in mice

Increasing evidence suggests that interleukin-1β (IL-1β) is a key mediator of the inflammatory response following traumatic brain injury (TBI). Recently, we showed that intracerebroventricular administration of an IL-1β-neutralizing antibody was neuroprotective following TBI in mice. In the present study, an anti-IL-1β antibody or control antibody was administered intraperitoneally following controlled cortical injury (CCI) TBI or sham injury in 105 mice and we extended our histological, immunological and behavioral analysis. First, we demonstrated that the treatment antibody reached target brain regions of brain-injured animals in high concentrations (> 11 nm) remaining up to 8 days post-TBI. At 48 h post-injury, the anti-IL-1β treatment attenuated the TBI-induced hemispheric edema (P < 0.05) but not the memory deficits evaluated using the Morris water maze (MWM). Neutralization of IL-1β did not influence the TBI-induced increases (P < 0.05) in the gene expression of the Ccl3 and Ccr2 chemokines, IL-6 or Gfap. Up to 20 days post-injury, neutralization of IL-1β was associated with improved visuospatial learning in the MWM, reduced loss of hemispheric tissue and attenuation of the microglial activation caused by TBI (P < 0.05). Motor function using the rotarod and cylinder tests was not affected by the anti-IL-1β treatment. Our results suggest an important negative role for IL-1β in TBI. The improved histological and behavioral outcome following anti-IL-1β treatment also implies that further exploration of IL-1β-neutralizing compounds as a treatment option for TBI patients is warranted.

Neurocognitive function in head and neck cancer patients prior to treatment

PURPOSE

Neurocognitive impairment is a common and clinically important problem in patients with cancer, but few studies have been conducted in head and neck cancer (HNC) patients. Our aims were to (1) determine the prevalence of baseline neurocognitive impairment in patients with newly diagnosed HNC, (2) examine the relationships between neurocognitive performance and self-reported neurocognitive function, and (3) explore relationships between neurocognitive function and sociodemographic, clinical, symptom distress, and mood variables.

METHODS

Seventy patients underwent testing with a brief neuropsychological test battery and completed self-report measures before starting treatment.

RESULTS

Forty-seven percent of HNC patients in the current cohort exhibited global neurocognitive impairment on neuropsychological testing prior to starting induction chemotherapy or concurrent chemoradiation. Impairment was more common in the following neurocognitive domains: verbal learning (36%), executive function (32%), verbal memory (30%), and processing speed (27%). Neurocognitive performance was not associated with self-reported neurocognitive function. Few significant associations were noted between neurocognitive performance and other physical or psychological symptoms; however, moderately strong associations were found between self-reported neurocognitive function and these symptoms.

CONCLUSIONS

Neurocognitive impairment is common in patients with newly diagnosed HNC before starting treatment. The impact of pretreatment neurocognitive impairment on treatment tolerance, treatment outcomes, and caregiving needs are important areas for future research. Mechanisms of pretreatment neurocognitive impairment also need to be explored.

Paradoxical sleep insomnia and decreased cholinergic neurons after myocardial infarction in rats

STUDY OBJECTIVES

Acute myocardial infarction (MI) is followed, within a few hours, by neuronal loss in the central nervous system (CNS), including the limbic system, the hypothalamus, and the brainstem. Sleep before and after MI was investigated in the first experiment. In a parallel experiment, 2 weeks after MI, we quantified brainstem cholinergic neurons known to control paradoxical sleep (PS).

MEASUREMENTS AND RESULTS

Data were obtained from 28 adult male Sprague-Dawley rats weighing 350-375 g and maintained under a 12-12 light-dark cycle in 2 experiments on 16 and 12 rats, respectively. The 16 animals in the first experiment were implanted with chronic electroencephalographic (EEG) and electromyographic (EMG) electrodes. A week after surgery, these animals were habituated for 2 days to the recording equipment, and baseline sleep was charted for 24 h. The next morning, MI was induced in 8 rats by occluding the left anterior descending coronary artery for 40 min. The remaining 8 rats served as sham-operated controls. Sleep was recorded again 2 weeks after MI. The number of choline acetyltransferase (ChAT)-positive neurons was counted in the second, parallel experiment on 6 MI and 6 sham rats. Compared to the sham controls, MI rats displayed longer latency to sleep onset, shorter latency to paradoxical sleep (PS), and curtailed PS duration. The number of ChAT-positive neurons in the pedunculopontine tegmentum (PPT) area of MI rats was significantly decreased compared to the sham controls, while the number of laterodorsal tegmentum (LDT) cholinergic neurons was not different.

CONCLUSION

Acute MI is accompanied, within 2 weeks, by PS-specific insomnia that can be explained, at least partly, by a specific loss of cholinergic neurons in an area known to control PS.

Involvement of pro- and anti-inflammatory cytokines and chemokines in the pathophysiology of traumatic brain injury

Despite dramatic improvements in the management of traumatic brain injury (TBI), to date there is no effective treatment available to patients, and morbidity and mortality remain high. The damage to the brain occurs in two phases, the initial primary phase being the injury itself, which is irreversible and amenable only to preventive measures to minimize the extent of damage, followed by an ongoing secondary phase, which begins at the time of injury and continues in the ensuing days to weeks. This delayed phase leads to a variety of physiological, cellular, and molecular responses aimed at restoring the homeostasis of the damaged tissue, which, if not controlled, will lead to secondary insults. The development of secondary brain injury represents a window of opportunity in which pharmaceutical compounds with neuroprotective properties could be administered. To establish effective treatments for TBI victims, it is imperative that the complex molecular cascades contributing to secondary injury be fully elucidated. One pathway known to be activated in response to TBI is cellular and humoral inflammation. Neuroinflammation within the injured brain has long been considered to intensify the damage sustained following TBI. However, the accumulated findings from years of clinical and experimental research support the notion that the action of inflammation may differ in the acute and delayed phase after TBI, and that maintaining limited inflammation is essential for repair. This review addresses the role of several cytokines and chemokines following focal and diffuse TBI, as well as the controversies around the use of therapeutic anti-inflammatory treatments versus genetic deletion of cytokine expression.

Use of animal models to understand the pandemic potential of highly pathogenic avian influenza viruses

It has been 40 years since the last influenza pandemic and it is generally considered that another could occur at any time. Recent introductions of influenza A viruses from avian sources into the human population have raised concerns that these viruses may be a source of a future pandemic strain. Therefore, there is a need to better understand the pathogenicity of avian influenza viruses for mammalian species so that we may be better able to predict the pandemic potential of such viruses and develop improved methods for their prevention and control. In this review, we describe the virulence of H5 and H7 avian influenza viruses in the mouse and ferret models. The use of these models is providing exciting new insights into the contribution of virus and host responses toward avian influenza viruses, virus tropism, and virus transmissibility. Identifying the role of individual viral gene products and mapping the molecular determinants that influence the severity of disease observed following avian influenza virus infection is dependent on the use of reliable animal models. As avian influenza viruses continue to cause human disease and death, animal pathogenesis studies identify avenues of investigation for novel preventative and therapeutic agents that could be effective in the event of a future pandemic.