Inflammatory Markers in Cerebrospinal Fluid from Patients with Hydrocephalus: A Systematic Literature Review

OBJECTIVE

The aim of this systematic review was to evaluate existing literature on inflammatory markers in CSF from patients with hydrocephalus and identify potential markers capable of promoting hydrocephalus development and progression.

METHODS

Relevant studies published before December 3rd 2020 were identified from PubMed, Embase, and reference lists. Studies were screened for eligibility using the predefined inclusion and exclusion criteria. Data from eligible studies were extracted, and sources of bias were evaluated. We included articles written in English investigating inflammatory markers in CSF from patients with hydrocephalus and control subjects. The review was conducted according to the PRISMA guidelines by three independent reviewers.

RESULTS

Twenty-two studies analyzed CSF from 311 patients with idiopathic normal pressure hydrocephalus (iNPH), 178 with posthemorrhagic hydrocephalus (PHH), 151 with other hydrocephalus diagnoses, and 394 control subjects. Fifty-eight inflammatory markers were investigated. The CSF of iNPH patients had increased CSF levels of IL-6, IL-1β, and LRG compared with control subjects, whereas the CSF of PHH patients had increased levels of IL-6, IL-18, and VEGF. CSF from patients with "other hydrocephalus diagnoses" had elevated IFN-γ compared to control subjects, and VEGF was increased in congenital hydrocephalus, spina bifida, and hydrocephalus associated with tuberculous meningitis compared with controls.

CONCLUSION

IL-6, IL-1β, LRG, IL-18, VEGF, and IFN-γ are elevated in CSF from patients with hydrocephalus and may be involved in promotion of hydrocephalus development and progression. They may serve as novel disease biomarkers, and their signaling pathways may represent targets for pharmacological management of hydrocephalus.

Effect of intraventricularly administered low-dose recombinant tissue plasminogen activator on interleukin 1-beta and transforming growth factor beta concentrations in cerebrospinal fluid of patients with primary intracerebral hemorrhage associated with intraventricular hemorrhage: A retrospective study

It is increasingly recognized that modulation of brain inflammation may uncover new potential therapeutic strategies for stroke. Recent studies have shifted focus from immunological implications in ischemic stroke to a more devastating form; the hemorrhagic stroke.The aim of this study was to investigate the neuroinflammatory response in cerebrospinal fluid in patients with primary intracerebral hemorrhage (ICH) associated with intraventricular hemorrhage (IVH) in the presence of low-dose recombinant tissue plasminogen activator (rt-PA).This retrospective study included 88 adults with primary ICH associated with IVH. Patients were divided into 2 groups: rt-PA group and non-rt-PA group, which received normal standard of care for this diagnosis. The rt-PA group was treated via catheter-based clot lysis using low-dose rt-PA injected through the external ventricular drain (EVD) system, and the non-rt-PA group was treated with saline applied to EVD system in equivalent volume. Cerebrospinal fluid samples from rt-PA were obtained from the EVD system at 4 time points: once before the drug administration, and then on day 1, 3, and 7. No attempt at randomization was made. The decision to inject rt-PA was based on the preference of the primary attending neurologist and the ability to obtain consent. Temporal interleukin-1 beta and transforming growth factor beta concentration changes were analyzed and compared between the 2 groups.The concentration of interleukin-1 beta was significantly lower in the rt-PA group than in the non-rt-PA group on day 7. In addition, the concentration of transforming growth factor beta was significantly higher in the rt-PA group than in the non-rt-PA group on day 1. There was a significant difference in interleukin-1 beta concentration between days 0 and 1 in comparison to day 3 in the rt-PA group, and between day 0 in comparison to day 3 and 7 in the non-rt-PA group. We also observed a significant difference in transforming growth factor beta concentration between days 0 and 1 and between days 3 and 7.The different pattern of pro- and anti-inflammatory cytokines in patients with ICH associated with IVH suggest distinct characteristics of secondary brain injury depending on the treatment modality.

Characterization of inflammatory cytokine profiles in cerebrospinal fluid of hand, foot, and mouth disease children with enterovirus 71-related encephalitis in Hangzhou, Zhejiang, China

Enterovirus 71 (EV71) is an important etiological agent of hand, foot, and mouth disease (HFMD), which can also lead to severe neurological complications (eg, encephalitis) in young children. Although a series of reports on EV71 infection have been published, the pathogenic mechanism of EV71 infection is still not fully understood.We evaluated the cerebrospinal fluid (CSF) levels of the inflammatory cytokines interleukin (IL)-8, IL-1β, IL-6, IL-10, tumor necrosis factor (TNF)-α, and IL-12p70 in 88 children with EV71-related encephalitis and 19 children with febrile convulsion (FC) with the use of commercial cytometric bead array kits.The levels of IL-8, IL-1β, IL-6, and IL-10 in CSF were significantly higher in encephalitis group when compared with those observed in FC group, while no significant changes were noted in the levels of TNF-α and IL-12p70. In addition, significant and positive correlations among CSF IL-8, IL-1β, IL-6, and IL-10 were observed in encephalitis group. Furthermore, receiver operator characteristic analysis determined a cut-off value of 10.62 pg/mL for IL-6 to discriminate encephalitis patients from FCs with the sensitivity and specificity of 89.8% and 84.2%, respectively. Moreover, logistic regression analyses revealed that IL-6 was an independent predictor of EV71-related encephalitis (odds ratio = 23.241, P < .001).Our results indicate that 4 inflammatory cytokines (IL-8, IL-1β, IL-6, and IL-10) play important roles in the pathogenesis of EV71 infection. IL-6 may be used for the evaluation of EV71-related encephalitis and as a potential therapy candidate for EV71 infection.

Evans Blue Reduces Neuropathic Pain Behavior by Inhibiting Spinal ATP Release

Upon peripheral nerve injury, vesicular ATP is released from damaged primary afferent neurons. This extracellular ATP subsequently activates purinergic receptors of the spinal cord, which play a critical role in neuropathic pain. As an inhibitor of the vesicular nucleotide transporter (VNUT), Evans blue (EB) inhibits the vesicular storage and release of ATP in neurons. Thus, we tested whether EB could attenuate neuropathic pain behavior induced by spinal nerve ligation (SNL) in rats by targeting VNUT. An intrathecal injection of EB efficiently attenuated mechanical allodynia for five days in a dose-dependent manner and enhanced locomotive activity in an SNL rat model. Immunohistochemical analysis showed that EB was found in VNUT immunoreactivity on neurons in the dorsal root ganglion and the spinal dorsal horn. The level of ATP in cerebrospinal fluid in rats with SNL-induced neuropathic pain decreased upon administration of EB. Interestingly, EB blocked ATP release from neurons, but not glial cells in vitro. Eventually, the loss of ATP decreased microglial activity in the ipsilateral dorsal horn of the spinal cord, followed by a reduction in reactive oxygen species and proinflammatory mediators, such as interleukin (IL)-1β and IL-6. Finally, a similar analgesic effect of EB was demonstrated in rats with monoiodoacetate-induced osteoarthritis (OA) pain. Taken together, these data demonstrate that EB prevents ATP release in the spinal dorsal horn and reduces the ATP/purinergic receptor-induced activation of spinal microglia followed by a decline in algogenic substances, thereby relieving neuropathic pain in rats with SNL.

Elevated inflammatory cytokine expression in CSF from patients with symptomatic thoracic disc herniation correlates with increased pain scores

BACKGROUND

The pathophysiology of pain in patients with symptomatic thoracic disc herniation (TDH) remains poorly understood. Mere mechanical compression of the spinal cord and/or the exiting nerve root by a prolapsed disc cannot explain the pathogenesis of pain in all cases. Previous studies report a direct correlation between the levels of proinflammatory cytokines in disc biopsies and the severity of leg pain in patients with lumbar disc herniation. A similar correlation in patients with TDH has not been investigated.

PURPOSE

To correlate the cerebrospinal fluid (CSF) expression of cytokines and pain-related amino acids with preoperative pain scores in patients with symptomatic TDH.

STUDY DESIGN

A prospective human study of CSF samples and clinical outcome scores.

METHODS

Using enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC), we determined inflammatory cytokine levels (TNF-α, IL-1β, and IL-10) and amino acid levels (glutamate, aspartate, gamma-aminobutyric acid, glycine, and arginine) in CSF samples from 10 patients with TDH and 10 control subjects who did not suffer an inflammatory disease nor pain related to spinal cord compression and subsequently correlated these levels with preoperative pain scores. Differences between both groups were evaluated by a Mann-Whitney U test. In order to estimate the correlation between cytokine or amino acid expression and pain scores, data were analyzed using a linear regression analysis.

RESULTS

No inflammatory cytokines were found in CSF samples from control subjects, whereas TNF-α, IL-1β, and IL-10 were detectable by ELISA in all CSF samples from patients with TDH. TNF-α and IL-10 but not IL-1β levels moderately correlated with preoperative pain scores. Elevated TNF-αlevels positively correlated with high pain scores; elevated IL-10 levels negatively correlated with high pain scores. Amino acids were detectable in all samples from both groups. There were no significant differences between the groups in any of the amino acids measured with HPLC.

CONCLUSION

Increased proinflammatory cytokine expression is associated with elevated pain scores in patients with symptomatic TDH. On the other hand, there is no conclusive correlation between the intensity of pain and the local or systemic presence of amino acids associated with pain transmission.

[Effect of vimentin on activation of NLRP3 inflammasome in the brain of mice with EV71 infection]

OBJECTIVE

To explore whether vimentin (VIM) mediates the activation of inflammasome in mice with EV71 infection in the central nervous system.

METHODS

Forty VIM knockout mice (VIM^-/-, 3 to 5 days old) were randomly divided into control group and infection group. The infection group was intraperitoneally injected with EV71 (10⁸ TCID₅₀), while the control group was injected with PBS (10 µL); another 40 wild-type mice (WT, 3 to 5 days old) were grouped in the same manner. The general conditions of mice were observed each day. Western blotting, ELISA, and RT-PCR were used to measure the levels of IL-1β and casepase-1 in the brain or cerebrospinal fluid. The pathological changes in the cerebella and brain were observed using immunohistochemistry.

RESULTS

Compared with the control group, the VIM^-/- mice infected with EV71 showed no significant changes in NLRP3, IL-1β or caspase-1 expression. The WT mice infected with EV71 showed obviously increased NLRP3, IL-1β, and caspase-1 expressions in the central nervous system. The neurons of infected VIM^-/- mice exhibited milder cell damage than the those in WT mice.

CONCLUSION

VIM mediates the activation of inflammasome and promotes brain inflammation and neuronal damage in mice with EV71 infection in the central nervous system.

The Aging Process Alters IL-1β and CD63 Levels Differently in Extracellular Vesicles Obtained from the Plasma and Cerebrospinal Fluid

OBJECTIVE(S)

The aim of this study was to investigate exosomal markers and inflammatory cargo of extracellular vesicles (EVs) obtained from cerebrospinal fluid (CSF) and plasma in the aging process. We also studied the inflammatory cargo by quantifying IL-1β levels.

METHODS

Male Wistar rats, aged 3 and 21 months, were used (n = 12 in each group). The CSF and plasma of animals were collected, and isolation of EVs was performed using a commercial kit. Total protein concentration, acetylcholinesterase (AChE) activity, and CD63 and IL-1β levels were evaluated.

RESULTS

AChE activity in EVs increased in both samples, specifically in the circulating EVs and those in the CSF of the older group. An age-related increase was observed in CD63 levels in EVs from the CSF but a decrease was observed in plasma EVs of the older group. Student's t test showed that the young adult rats had significantly higher circulating IL-1β levels in the EVs compared to the aged ones, without any effect on central content.

CONCLUSION

Our data suggest that the normal aging process causes different changes in the profiles of central and circulating EVs. Altered IL-1β levels in circulating EVs can be linked, at least partly, to age-related inflammatory conditions, and a disruption of the CFS exosomes in aged rats, evaluated by CD63 levels, can be related to susceptibility to neurodegenerative disorders.

A comparison of blood and cerebrospinal fluid cytokines (IL-1β, IL-6, IL-18, TNF-α) in neonates with perinatal hypoxia

Perinatal hypoxia-ischemia is a specific and important pathological event in neonatal care practice. The data on relationship between the concentrations of cytokines in blood and cerebrospinal fluid (CSF) and perinatal brain injury are scarce. The aim of this study is to evaluate changes in interleukin (IL-1β, IL-6, and IL-18) and tumor necrosis factor alpha (TNF-α) levels in newborns with perinatal hypoxia (PNH). CSF and serum samples of 35 term and near-term (35-40 weeks) newborns with PNH, at the age of 3-96 hours, were analyzed using enzyme-linked immunosorbent assay. Control group consisted of 25 non-asphyxic/non-hypoxic infants of the same age sampled for clinically suspected perinatal meningitis, but proven negative and healthy otherwise. The cytokine values in CSF and serum samples were determined in relation to initial hypoxic-ischemic encephalopathy (HIE) staged according the Sarnat/Sarnat method, and compared with neurological outcome at 12 months of age estimated using Amiel-Tison procedure. The concentrations of IL-6 and TNF-α in serum of PNH patients were significantly higher compared to control group (p = 0.0407 and p = 0.023, respectively). No significant difference between average values of cytokines in relation to the stage of HIE was observed. Significantly higher levels of IL-6 and IL-18 corresponded to a mildly abnormal neurological outcome, while higher levels of IL-6 and TNF-α corresponded to a severely abnormal neurological outcome, at 12 months of age. Elevated serum levels of IL-6 and TNF-α better corresponded with hypoxia/ischemia compared to CSF values, within 96 hours of birth. Also, higher serum levels of IL-6, TNF-α, and IL-18 corresponded better with abnormal neurological outcome at 12 months of age, compared to CSF values.

Cerebrospinal fluid neuron specific enolase, interleukin-1β and erythropoietin concentrations in children after seizures

PURPOSE

In the present study, the levels of neuron-specific enolase (NSE), interleukin-1β (IL-1β), and erythropoietin (EPO) in cerebrospinal fluid (CSF) in children with idiopathic epilepsy were measured to illuminate the relationships between these markers with idiopathic epilepsy.

METHODS

Eighty-five children from 6 months to 12.5 years of age with single, previously undiagnosed, and untreated idiopathic epilepsy were participated in this study. The concentrations of CSF NSE, 1L-1β, and EPO were measured by specific ELISA methods.

RESULTS

The mean concentrations of CSF NSE, IL-1β, and EPO in the epileptic groups showed a significant increase (P < 0.01) compared with those in the control groups. Besides, the mutual correlations of NSE, 1L-1β, and EPO were also analyzed. Results showed that there were positive correlations between the levels of IL-1β, NSE, and EPO.

CONCLUSIONS

The changes of NSE, 1L-1β, and EPO level in CSF may be beneficial for the pathophysiology study of epileptic seizures and the identification and diagnosis of a seizure clinically.

Increased interleukin-1β and basic fibroblast growth factor levels in the cerebrospinal fluid during human herpesvirus-6B (HHV-6B) encephalitis

Human herpesvirus 6B (HHV-6B) causes exanthema subitum in infants and is known to be mildly pathogenic. However, HHV-6B infection can induce febrile seizures in a high percentage of patients, and in rare cases, result in encephalitis. We detected higher levels of interleukin (IL)-1β and basic fibroblast growth factor (bFGF) in the cerebrospinal fluid (CFS) of patients with HHV-6B encephalitis when compared to those in patients with non-HHV-6B-induced febrile seizures. In vitro, IL-1β and bFGF enhanced HHV-6B gene expression in infected U373 astrocytes during the initial and maintenance phases of infection, respectively. These findings indicated that IL-1β and bFGF contribute to HHV-6B growth and the onset of encephalitis.

RANTES correlates with inflammatory activity and synaptic excitability in multiple sclerosis

BACKGROUND

Alterations of synaptic transmission induced by inflammatory activity have been linked to the pathogenic mechanisms of multiple sclerosis (MS). Regulated upon activation, normal T-cell expressed, and secreted (RANTES) is a pro-inflammatory chemokine involved in MS pathophysiology, potentially able to regulate glutamate release and plasticity in MS brains, with relevant consequences on the clinical manifestations of the disease.

OBJECTIVE

To assess the role of RANTES in the regulation of cortical excitability.

METHODS

We explored the association of RANTES levels in the cerebrospinal fluid (CSF) of newly diagnosed MS patients with magnetic resonance imaging (MRI) and laboratory measures of inflammatory activity, as well its role in the control of cortical excitability and plasticity explored by means of transcranial magnetic stimulation (TMS), and in hippocampal mouse slices in vitro.

RESULTS

CSF levels of RANTES were remarkably high only in active MS patients and were correlated with the concentrations of interleukin-1β. RANTES levels were associated with TMS measures of cortical synaptic excitability, but not with long-term potentiation (LTP)-like plasticity. Similar findings were obtained in mouse hippocampal slices in vitro, where we observed that RANTES enhanced basal excitatory synaptic transmission with no effect on LTP.

CONCLUSION

RANTES correlates with inflammation and synaptic excitability in MS brains.

[THE RELATIONSHIP BETWEEN SERUM AND LIQUOR IL-1β, IL-6, TNFα, IL-10 LEVELS AND CLINICAL, COGNITIVE AND FUNCTIONAL CHARACTERISTICS IN ACUTE ISCHEMIC STROKE]

INTRODUCTION

Inflammation is probably the main process that links cardiovascular risk factors with damage to blood vessels and neurons. Elucidation of mechanisms of this relationship is an important issue.

MATERIALS AND METHODS

70 acute stroke patients were studied to assess their neuropsychological (MMSE, MoCA, FAB, Clock Drawing Test, Shulte Tables and Verbal Fluency) and functional status (mRS, Rivermead Mobility Index). The serum and liquor IL-1β, IL-6, TNFa and IL-10 levels were analyzed. Control group included subjects without cerebrovascular diseases.

RESULTS

Stroke patients had higher IL-10 serum concentration than controls. No difference was found for other cytokines. There was correlation between serum and liquor cytokines levels. We found positive correlation between IL-1β, IL-6 and IL-10 levels. High IL-1β concentration was associated with vascular risk factors, cardio embolic stroke, enhanced severity of cerebral stroke, low processing speed, impaired executive and visual-spatial functions and higher grade of mRS on discharge. The same pattern was revealed for IL-6 and IL-10. IL-6 level was related to mRS without relation to NIHSS on admission. High TNFa concentration was linked with vascular risk factors, low MMSE score and processing speed.

DISCUSSION

Despite the antagonistic effects of IL-1β, IL-6 and IL-10 on inflammation, associations of these cytokines with anamnestic, clinical, neuropsychological and functional characteristics were similar in acute ischemic stroke. Probably, this fact indicates that during the acute ischemic brain damage process the immune response develops at the same time in pro- and anti-inflammatory directions. Its magnitude correlates with the damage severity and is associated with the effects of vascular risk factors before stroke.

Meta-Analysis of Cytokines and Chemokines in Suicidality: Distinguishing Suicidal Versus Nonsuicidal Patients

BACKGROUND

Major psychiatric disorders are associated with inflammation. Aberrant cytokine and chemokine levels have been associated with psychiatric disorders and suicidal behavior. We performed a meta-analysis of cytokine and chemokine levels in patients with versus without suicidality and patients with suicidality versus healthy controls.

METHODS

We identified articles by searching MEDLINE, PsycINFO, and Thomson Reuters Web of Knowledge databases and the reference lists of identified studies.

RESULTS

Study inclusion criteria were met by 18 studies comprising 583 patients with suicidality, 315 patients without suicidality, and 845 healthy control subjects. Levels of interleukin (IL)-1β and IL-6 were significantly increased in blood and postmortem brain samples of patients with suicidality compared with both patients without suicidality and healthy control subjects (p < .05 for each). In vitro IL-2 production by peripheral blood mononuclear cells was significantly decreased in patients with suicidality compared with both patients without suicidality and healthy controls (p < .01 for each). Cerebrospinal fluid levels of IL-8 were significantly decreased in patients with suicidality versus control subjects (p < .05).

CONCLUSIONS

We found evidence for aberrant cytokine levels in blood, cerebrospinal fluid, and postmortem brain samples of patients with suicidality. Levels of IL-1β and IL-6 were most robustly associated with suicidality, and these cytokines may help distinguish suicidal from nonsuicidal patients. Rigorously designed longitudinal studies are needed to evaluate these associations further.

Cerebrospinal fluid markers of neuroinflammation in delirium: a role for interleukin-1β in delirium after hip fracture

OBJECTIVE

Exaggerated central nervous system (CNS) inflammatory responses to peripheral stressors may be implicated in delirium. This study hypothesised that the IL-1β family is involved in delirium, predicting increased levels of interleukin-1β (IL-1β) and decreased IL-1 receptor antagonist (IL-1ra) in the cerebrospinal fluid (CSF) of elderly patients with acute hip fracture. We also hypothesised that Glial Fibrillary Acidic Protein (GFAP) and interferon-γ (IFN-γ) would be increased, and insulin-like growth factor 1 (IGF-1) would be decreased.

METHODS

Participants with acute hip fracture aged >60 (N=43) were assessed for delirium before and 3-4 days after surgery. CSF samples were taken at induction of spinal anaesthesia. Enzyme-linked immunosorbent assays (ELISA) were used for protein concentrations.

RESULTS

Prevalent delirium was diagnosed in eight patients and incident delirium in 17 patients. CSF IL-1β was higher in patients with incident delirium compared to never delirium (incident delirium 1.74 pg/ml (1.02-1.74) vs. prevalent 0.84 pg/ml (0.49-1.57) vs. never 0.66 pg/ml (0-1.02), Kruskal-Wallis p=0.03). CSF:serum IL-1β ratios were higher in delirious than non-delirious patients. CSF IL-1ra was higher in prevalent delirium compared to incident delirium (prevalent delirium 70.75 pg/ml (65.63-73.01) vs. incident 31.06 pg/ml (28.12-35.15) vs. never 33.98 pg/ml (28.71-43.28), Kruskal-Wallis p=0.04). GFAP was not increased in delirium. IFN-γ and IGF-1 were below the detection limit in CSF.

CONCLUSION

This study provides novel evidence of CNS inflammation involving the IL-1β family in delirium and suggests a rise in CSF IL-1β early in delirium pathogenesis. Future larger CSF studies should examine the role of CNS inflammation in delirium and its sequelae.

[Effects of telmisartan on the level of Aβ1-42, interleukin-1β, tumor necrosis factor α and cognition in hypertensive patients with Alzheimer's disease]

OBJECTIVE

To explore the effects of telmisartan, an angiotensin II type 1 receptor blocker with peroxisome proliferator-activated receptor γ-stimulating activity, on the levels of Aβ1-42, interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α) and cognition in elderly hypertensive patients with Alzheimer's disease (AD).

METHODS

A total of 48 patients with probable AD and essential hypertension were randomly assigned into telmisartan group (n = 24, 40 - 80 mg qd) or amlodipine group (n = 24, 5 - 10 mg qd) for 6 months at Henan Provincial People's Hospital during 2008 - 2011. Cognitive evaluations were assessed at pre-treatment and 24 weeks post-treatment by clinical assessment, rating scales and neuropsychological tests while the cerebrospinal fluid (CSF) levels of Aβ1-42, IL-1β and TNF-α by enzyme-linked immunosorbent assay (ELISA).

RESULTS

After 6 months, mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) significantly decreased compared with baseline values to a similar extent in both groups. No significant differences existed between two groups in SBP or DBP. The patients displayed significantly higher Aβ1-42 and greatly lower levels of IL-1β and TNF-α in the telmisartan group versus the amlodipine group (P < 0.05). At 24 weeks, the patients in the telmisartan group had better mini-mental state examination (MMSE) (22.0 ± 3.4) and Alzheimer's disease assessment scale-cognitive subscale (ADAS-cog) (15 ± 5) scales scores than those taking amlodipine (MMSE (19.5 ± 2.8) and ADAS-cog (18 ± 5). Patients treated with telmisartan had better improvement on the MMSE (P < 0.05) and ADAS-cog (P < 0.05) scales compared with the amlodipine group by the end of study week 24.

CONCLUSION

Telmisartan may delay the decreased level of Aβ1-42 and reduce the levels IL-1β and TNF-α in CSF so as to improve the cognitive function of elderly hypertensive patients with AD. With additional benefits in comparison with common antihypertensive drugs, it may offer a novel therapeutic strategy of AD.

Attenuation of interleukin-1beta by pulsed electromagnetic fields after traumatic brain injury

Traumatic Brain Injury (TBI) is a major cause of morbidity and mortality in civilian and military populations. Interleukin-1beta (IL-1β) is a pro-inflammatory cytokine with a key role in the inflammatory response following TBI and studies indicate that attenuation of this cytokine improves behavioral outcomes. Pulsed electromagnetic fields (PEMF) can reduce inflammation after soft tissue injuries in animals and humans. Therefore, we explored whether PEMF signals could alter the course of IL-1β production in rats subjected to closed-head contusive weight-drop injuries (Marmarou method) and penetrating needle-stick brain injuries. Protein levels, measured by the Biorad assay, were not altered by injuries or PEMF treatment. In addition, we verified that IL-1β levels in cerebrospinal fluid (CSF) were proportional to injury severity in the contusion model. Results demonstrate that PEMF treatment attenuated IL-1β levels up to 10-fold in CSF within 6h after contusive injury and also significantly suppressed IL-1β within 17-24h after penetrating injury. In contrast, no differences in IL-1β were seen between PEMF-treated and control groups in brain homogenates. To the authors' knowledge, this is the first report of the use of PEMF to modulate an inflammatory cytokine after TBI. These results warrant further studies to assess the effects of PEMF on other inflammatory markers and functional outcomes.

[Humoral and cellular immune responses in neuromyelitis optica]

Neuromyelitis optica (NMO) is an inflammatory and demyelinating syndrome characterized by severe attacks of myelitis and optic neuritis. A crucial role for humoral immunity in the NMO pathogenesis has been suggested by the detection of a highly specific serum autoantibody NMO immunoglobulin G that binds to aquaporin-4 (AQP4) water channels, and the pronounced deposition of immunoglobulins colocalizing with products of complement activation in a vasculocentric pattern around thickened hyalinized blood vessels in NMO lesions. Moreover, we have recently demonstrated that levels of several cytokines such as interleukin (IL)-6 and IL-1β are increased in the cerebrospinal fluid of NMO patients, and the peripheral white matter-demyelinating cord lesions of NMO were accompanied by infiltration of lymphocytes in the leptomeningeal membrane. These cellular elements in patients with NMO might aid B cells and plasma cells in AQP4 antibody production, and break the blood-brain barrier due to the access of AQP4 antibodies to the extracellular domain of AQP4 at the astrocytic foot process.

Increased umbilical cord plasma interleukin-1 beta levels was correlated with adverse outcomes of neonatal hypoxic-ischemic encephalopathy

To explore whether or not the umbilical blood levels of cytokines can be used to indicate the adverse outcomes of hypoxic-ischemic encephalopathy (HIE) patients. Umbilical artery blood and peripheral venous blood samples were collected on the 1st, 3rd and 7th days after birth to detect the levels of IL-1 beta, IL-8 and TNF-alpha. Neurological examination and Denver developmental screening test (DDST-II) were performed at the 6 and 12 months evaluations to detect any neurodevelopmental abnormalities. The results showed: (i) the serum concentrations of IL-1 beta, IL-8 and TNF-alpha in umbilical and peripheral blood were significantly higher in HIE patients than control groups; (ii) the umbilical blood concentrations of IL-1 beta exhibited the best positive correlation with HIE grades, when compared with IL-8 and TNF-alpha; and (iii) abnormal neurological outcomes at 6 and 12 months of age were best predicted by umbilical levels of IL-1 beta. Thus, umbilical concentrations of IL-1 beta were associated with the grades and adverse outcomes of HIE.

Levels of IL-1beta and IL-1ra in cerebrospinal fluid of human patients after single and prolonged seizures

BACKGROUND

Experimentally induced seizures are associated with increased production of inflammatory cytokines in the nervous system. Elevated cerebrospinal fluid levels of cytokine interleukin-6 (IL-6) have been found after a single generalized seizure in human patients. After prolonged seizures, levels of IL-6 have been shown to be even higher compared with single seizures. In the present study, we determined the levels of proconvulsive IL-1beta and anticonvulsive IL-1ra in cerebrospinal fluid after single tonic-clonic seizures as well as after prolonged seizures.

METHODS

The levels of cytokines were measured using enzyme-linked immunosorbent assay.

RESULTS

We found that after single seizures, a slight increase in anticonvulsive IL-1ra levels was found; however, after prolonged partial or recurrent tonic-clonic seizures, the levels of IL-1ra were significantly elevated, together with decreased IL-1beta levels.

CONCLUSION

Our results indicate that after severe seizures, the balance between IL-1-type cytokines is changed towards a neuroprotective and anticonvulsive direction with an overproduction of IL-1ra with respect to potentially neurotoxic IL-1beta. This reaction may serve as a defense mechanism of the nervous system against excitotoxic neuronal damage.

Nerve growth factor expression correlates with severity and outcome of traumatic brain injury in children

BACKGROUND

Secondary brain damage after traumatic brain injury (TBI) involves neuro-inflammatory mechanisms, mainly dependent on the intracerebral production of cytokines. In particular, interleukin 1beta (IL-1beta) is associated with neuronal damage, while interleukin 6 (IL-6) exerts a neuroprotective role due to its ability to modulate neurotrophins biosynthesis. However, the relationship between these cytokines and neurotrophins with the severity and outcome of TBI remains still controversial.

AIMS

To determine whether the concentration of IL-1beta and IL-6 and neurotrophins (nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), glial-derived neurotrophic factor (GDNF)) in the cerebrospinal fluid (CSF) of children with TBI correlates with the severity of the injury and its neurologic outcome.

METHODS

Prospective observational clinical study in a university hospital. CSF samples were collected from 27 children at 2h (Time T1) and 48 h (Time T2) after severe TBI, and from 21 matched controls. Severity of TBI was evaluated by GCS and neurologic outcome by GOS. CSF concentrations of cytokines and neurotrophins were measured by immunoenzymatic assays.

RESULTS

Early NGF and IL-1beta concentrations (T1) correlated significantly with the severity of head injury, whereas no correlation was found for IL-6, BDNF, and GDNF. Furthermore, higher NGF and IL-6 and lower IL-1beta expression at T2 were associated with better neurologic outcomes. No significant association was found between BDNF or GDNF expression and neurologic outcome.

CONCLUSIONS

NGF concentration in CSF is a useful marker of brain damage following severe TBI and its up-regulation, in the first 48 h after head injury together with lower IL-1beta expression, correlates with a favorable neurologic outcome. Clinical and prognostic information may also be obtained from IL-6 expression.

Interleukin-1 system in CNS stress: seizures, fever, and neurotrauma

Proteins of the interleukin-1 (IL-1) system include the secreted agonist IL-1beta, and the receptor antagonist IL-1ra, both competing for binding to the IL-1 receptor (IL-1R). IL-1beta and IL-1ra are highly inducible under different forms of stress, such as excitatory neurotransmitter excess occurring during seizures, in infection and inflammation, and during neurotrauma. In each of these conditions induction of IL-1beta precedes that of IL-1ra, resulting in up to 10-20-fold elevation of IL-1beta concentrations. Consequently, IL-1beta induces the elevation of other proinflammatory molecules, including IL-6, IL-1R1, COX2, and iNOS, as well as of IL-1ra. Elevation of IL-1ra is of key importance for quenching the inflammatory response at the IL-1R1 as part of an autoregulatory loop. In seizures, IL-1ra is a strong anticonvulsant and in IL-1beta-dependent fever, a powerful antipyretic. In traumatic brain injury (TBI), the ability of patients to mount an IL-1ra response, as measured in the CSF, strongly correlated with the neurological outcome. Selective induction or pharmacological application of IL-1ra may be sparing neurons in seizures and neurotrauma.

Variations in the response of interleukins in neurosurgical intensive care patients monitored using intracerebral microdialysis

OBJECT

The aim of this study was to make a preliminary evaluation of whether microdialysis monitoring of cytokines and other proteins in severely diseased neurosurgical patients has the potential of adding significant information to optimize care, thus broadening the understanding of the function of these molecules in brain injury.

METHODS

Paired intracerebral microdialysis catheters with high-cutoff membranes were inserted in 14 comatose patients who had been treated in a neurosurgical intensive care unit following subarachnoidal hemorrhage or traumatic brain injury. Samples were collected every 6 hours (for up to 7 days) and were analyzed at bedside for routine metabolites and later in the laboratory for interleukin (IL)-l and IL-6; in two patients, vascular endothelial growth factor and cathepsin-D were also checked. Aggregated microprobe data gave rough estimations of profound focal cytokine responses related to morphological tissue injury and to anaerobic metabolism that were not evident from the concomitantly collected cerebrospinal fluid data. Data regarding tissue with no macroscopic evidence of injury demonstrated that IL release not only is elicited in severely compromised tissue but also may be a general phenomenon in brains subjected to stress. Macroscopic tissue injury was strongly linked to IL-6 but not IL- lb activation. Furthermore, IL release seems to be stimulated by local ischemia. The basal tissue concentration level of IL-lb was estimated in the range of 10 to 150 pg/ml; for IL-6, the corresponding figure was 1000 to 20,000 pg/ml.

CONCLUSIONS

Data in the present study indicate that catheters with high-cutoff membranes have the potential of expanding microdialysis to the study of protein chemistry as a routine bedside method in neurointensive care.

Interleukin-1beta, interleukin-18, and interferon-gamma expression in the cerebrospinal fluid of premature infants with posthemorrhagic hydrocephalus--markers of white matter damage?

Posthemorrhagic hydrocephalus (PHHC) represents a major complication of preterm birth. The aim of this study was to determine whether cerebrospinal fluid (CSF) levels of the pro-inflammatory cytokines IL-1beta, IL-18, and interferon (IFN)-gamma are altered in the CSF of preterm infants with PHHC and may serve as a marker of white matter damage (WMD). Twenty-seven preterm infants with PHHC were included in the study; 13 of them had signs of cystic WMD (cWMD) on ultrasound examinations. CSF sample 1 was obtained at first ventriculostomy, sample 2 at shunt implantation. Results were compared with a control group of 20 age-matched patients without neurologic diseases. IL-1beta concentrations were elevated in CSF sample 1 of PHHC patients without WMD and in sample 1 of patients with cWMD. Concentrations of IL-18 were increased in both samples of patients without WMD and in sample 2 of patients with cWMD. CSF levels of IFN-gamma were elevated in sample 1 of PHHC patients with cWMD. The pro-inflammatory cytokine IL-1beta and IL-18 levels in the CSF are elevated in patients with PHHC. Higher IFN-gamma levels are detected in a subgroup of patients developing cWMD, indicating its involvement in the pathogenesis of cWMD in the context of PHHC.