Elevated Systemic IL-6 Levels in Patients with Aneurysmal Subarachnoid Hemorrhage Is an Unspecific Marker for Post-SAH Complications

Application of LRG mechanism in normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) is a prevalent type of hydrocephalus, including secondary normal pressure hydrocephalus (SNPH) and idiopathic normal pressure hydrocephalus (INPH). However, its clinical diagnosis and pathological mechanism are still unclear. Leucine-rich α-2 glycoprotein (LRG) is involved in various human diseases, including cancer, diabetes, cardiovascular disease, and nervous system diseases. Now the physiological mechanism of LRG is still being explored. According to the current research results on LRG, we found that the agency of LRG has much to do with the known pathological process of NPH. This review focuses on analyzing the LRG signaling pathways and the pathological mechanism of NPH. According to the collected literature evidence, we speculated that LRG probably be involved in the pathological process of NPH. Finally, based on the mechanism of LRG and NPH, we also summarized the evidence of molecular targeted therapies for future research and clinical application.

Characterization of CSF inflammatory markers after hemorrhagic stroke and their relationship to disease severity

Background

The inflammatory response within the central nervous system is a key driver of secondary brain injury after hemorrhagic stroke, both in patients with intracerebral hemorrhage (ICH) and aneurysmal subarachnoid hemorrhage (aSAH). In this study, we aimed to characterize inflammatory molecules in the blood and cerebrospinal fluid (CSF) of patients within 72 hours of hemorrhage to understand how such molecules vary across disease types and disease severity.

Methods

Biological samples were collected from patients admitted to a single-center Neurosciences Intensive Care Unit with a diagnosis of ICH or aSAH between 2014 and 2022. Control CSF samples were collected from patients undergoing CSF diversion for normal pressure hydrocephalus. A panel of immune molecules in the plasma and CSF samples was analyzed using Cytometric Bead Array assays. Clinical variables, including demographics, disease severity, and intensive care unit length of stay were collected.

Results

Plasma and/or CSF samples were collected from 260 patients (188 ICH patients, 54 aSAH patients, 18 controls). C-C motif chemokine ligand-2 (CCL2), interleukin-6 (IL-6), granulocyte-colony stimulating factor (G-CSF), interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF), were detectable in the CSF within the first 3 days after hemorrhage, and all were elevated compared to plasma. Compared with controls, CCL2, IL-6, IL-8, G-CSF, and VEGF were elevated in the CSF of both ICH and aSAH patients (p<0.01 for all comparisons). VEGF was increased in ICH patients compared to aSAH patients (p<0.01). CCL2, G-CSF, and VEGF in the CSF were associated with more severe disease in aSAH patients only.

Conclusions

Within 3 days of hemorrhagic stroke, proinflammatory molecules can be detected in the CSF at higher concentrations than in the plasma. Early concentrations of some pro-inflammatory molecules may be associated with markers of disease severity.

CSF hypersecretion versus impaired CSF absorption in posthemorrhagic hydrocephalus: a systematic review

BACKGROUND

The molecular mechanisms underlying development of posthemorrhagic hydrocephalus (PHH) remain elusive. The aim of this systematic review was to evaluate existing literature on increased CSF secretion and impaired CSF absorption as pathogenic contributors to CSF accumulation in neonatal and adult PHH.

METHODS

The systematic review was conducted in accordance with the PRISMA guidelines. Relevant studies published before March 11th, 2023, were identified from PubMed and reference lists. Studies were screened for eligibility using predefined inclusion and exclusion criteria. Data from eligible studies were extracted and potential sources of bias were evaluated.

RESULTS

Nineteen studies quantified CSF production rates and/or CSF absorption capacity in human patients with PHH or animals with experimentally induced PHH. Increased CSF production was reported as early as 24 h and as late as 28 days post ictus in six out of eight studies quantifying CSF production rates in animals with experimentally induced PHH. Impaired CSF absorption was reported in all four studies quantifying CSF absorption capacity in human patients with PHH and in seven out of nine studies quantifying CSF absorption capacity in animals with experimentally induced PHH. Impaired CSF absorption was reported as early as 30 min and as late as 10 months post ictus.

CONCLUSIONS

The pathological CSF accumulation in PHH likely arises from a combination of increased CSF secretion and impaired CSF absorption, which may manifest at different time scales following a hemorrhagic event. Emergent evidence on increased CSF secretion by the choroid plexus may herald a paradigm shift in our understanding of PHH.

In vitro investigation of the effect of proinflammatory cytokines on mouse choroid plexus membrane transporters Ncbe and NKCC1

Intraventricular hemorrhage is a potentially life-threatening condition. Approximately 20% of patients develop posthemorrhagic hydrocephalus with increased ventricular volume and intracranial pressure. Hydrocephalus develops partially due to increased secretion of cerebrospinal fluid by the choroid plexus. During hemorrhage a multitude of factors are released into the cerebrospinal fluid. Many of these have been implicated in the hypersecretion. In this study, we have investigated the isolated effect of inflammatory components, on the abundance of two membrane transporters involved in cerebrospinal fluid secretion by the choroid plexus: the Na+-dependent Cl-/HCO3- exchanger, Ncbe, and the Na+, K+, 2Cl- cotransporter, NKCC1. We have established a primary choroid plexus epithelial cell culture from 1 to 7 days old mouse pups. Seven days after seeding, the cells formed a monolayer. The cells were treated with either tumor necrosis factor alpha (TNFα), interleukin 1 beta (IL-1β), or interleukin 6 (IL-6) to mimic inflammation. The data show that treatment with TNFα, and IL-1β only transiently increased NKCC1 abundance whereas the effect on Ncbe abundance was a transient decrease. IL-6 however significantly increased NKCC1 (242%), the phosphorylated NKCC1 (147%), as well as pSPAK (406%) abundance, but had no effect on Ncbe. This study suggests that the inflammatory pathway involved in hypersecretion primarily is mediated by activation of basolateral receptors in the choroid plexus, mainly facilitated by IL-6. This study highlights the complexity of the pathophysiological circumstances occurring during intraventricular hemorrhage.

Lower levels of Th1 and Th2 cytokines in cerebrospinal fluid (CSF) at the time of initial CSF shunt placement in children are associated with subsequent shunt revision surgeries

OBJECTIVE

We compare cytokine profiles at the time of initial CSF shunt placement between children who required no subsequent shunt revision surgeries and children requiring repeated CSF shunt revision surgeries for CSF shunt failure. We also describe the cytokine profiles across surgical episodes for children who undergo multiple subsequent revision surgeries.

METHODS

This pilot study was nested within an ongoing prospective multicenter study collecting CSF samples and clinical data at the time of CSF shunt surgeries since August 2014. We selected cases where CSF was available for children who underwent an initial CSF shunt placement and had no subsequent shunt revision surgeries during >=24 months of follow-up (n = 7); as well as children who underwent an initial CSF shunt placement and then required repeated CSF shunt revision surgeries (n = 3). Levels of 92 human cytokines were measured using the Olink immunoassay and 41 human cytokines were measured using Luminex based bead array on CSF obtained at the time of each child's initial CSF shunt placement and were displayed in heat maps.

RESULTS

Qualitatively similar profiles for the majority of cytokines were observed among the patients in each group in both Olink and Luminex assays. Lower levels of MCP-3, CASP-8, CD5, CXCL9, CXCL11, eotaxin, IFN-γ, IL-13, IP-10, and OSM at the time of initial surgery were noted in the children who went on to require multiple surgeries. Pro- and anti-inflammatory cytokines were selected a priori and shown across subsequent revision surgeries for the 3 patients. Cytokine patterns differed between patients, but within a given patient pro-inflammatory and anti-inflammatory cytokines acted in a parallel fashion, with the exception of IL-4.

CONCLUSIONS

Heat maps of cytokine levels at the time of initial CSF shunt placement for each child undergoing only a single initial CSF shunt placement and for each child undergoing repeat CSF shunt revision surgeries demonstrated qualitatively similar profiles for the majority of cytokines. Lower levels of MCP-3, CASP-8, CD5, CXCL9, CXCL11, eotaxin, IFN-γ, IL-13, IP-10, and OSM at the time of initial surgery were noted in the children who went on to require multiple surgeries. Better stratification by patient age, etiology, and mechanism of failure is needed to develop a deeper understanding of the mechanism of inflammation in the development of hydrocephalus and response to shunting in children.

Biomarkers in aneurysmal subarachnoid hemorrhage: A short review

Poor outcomes of aneurysmal subarachnoid hemorrhage (aSAH) can be the result of the initial catastrophic event or the many acute or delayed neurological complications. Recent evidence suggests that some molecules play a critical role in both events, through some unknown pathways involved. Understanding the role of these molecules in these events could allow to improve diagnostic accuracy, guide management, and prevent long-term disability in aSAH. Here we present the studies on aSAH biomarkers present in current medical literature, highlighting their roles and main results.

Systemic Inflammation after Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is one of the most severe neurological disorders, with a high mortality rate and severe disabling functional sequelae. Systemic inflammation following hemorrhagic stroke may play an important role in mediating intracranial and extracranial tissue damage. Previous studies showed that various systemic inflammatory biomarkers might be useful in predicting clinical outcomes. Anti-inflammatory treatment might be a promising therapeutic approach for improving the prognosis of patients with aSAH. This review summarizes the complicated interactions between the nervous system and the immune system.

Anti-Inflammatory Drug Therapy in Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis of Prospective Randomized and Placebo-Controlled Trials

Emerging evidence suggests that neuroinflammation may play a potential role in aneurysmal subarachnoid hemorrhage (aSAH). We aim to analyze the influence of anti-inflammatory therapy on survival and outcome in aSAH. Eligible randomized placebo-controlled prospective trials (RCTs) were searched in PubMed until March 2023. After screening the available studies for inclusion and exclusion criteria, we strictly extracted the main outcome measures. Dichotomous data were determined and extracted by odds ratio (OR) with 95% confidence intervals (CIs). Neurological outcome was graded using the modified Rankin Scale (mRS). We created funnel plots to analyze publication bias. From 967 articles identified during the initial screening, we included 14 RCTs in our meta-analysis. Our results illustrate that anti-inflammatory therapy yields an equivalent probability of survival compared to placebo or conventional management (OR: 0.81, 95% CI: 0.55-1.19, p = 0.28). Generally, anti-inflammatory therapy trended to be associated with a better neurologic outcome (mRS ≤ 2) compared to placebo or conventional treatment (OR: 1.48, 95% CI: 0.95-2.32, p = 0.08). Our meta-analysis showed no increased mortality form anti-inflammatory therapy. Anti-inflammatory therapy in aSAH patients tends to improve the neurological outcome. However, multicenter, rigorous, designed, prospective randomized studies are still needed to investigate the effect of fighting inflammation in improving neurological functioning after aSAH.

Immunological Profile of Vasospasm after Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) carries high mortality and disability rates, which are substantially driven by complications. Early brain injury and vasospasm can happen after SAH and are crucial events to prevent and treat to improve prognosis. In recent decades, immunological mechanisms have been implicated in SAH complications, with both innate and adaptive immunity involved in mechanisms of damage after SAH. The purpose of this review is to summarize the immunological profile of vasospasm, highlighting the potential implementation of biomarkers for its prediction and management. Overall, the kinetics of central nervous system (CNS) immune invasion and soluble factors' production critically differs between patients developing vasospasm compared to those not experiencing this complication. In particular, in people developing vasospasm, a neutrophil increase develops in the first minutes to days and pairs with a mild depletion of CD45+ lymphocytes. Cytokine production is boosted early on after SAH, and a steep increase in interleukin-6, metalloproteinase-9 and vascular endothelial growth factor (VEGF) anticipates the development of vasospasm after SAH. We also highlight the role of microglia and the potential influence of genetic polymorphism in the development of vasospasm and SAH-related complications.

Impaired neurogenesis with reactive astrocytosis in the hippocampus in a porcine model of acquired hydrocephalus

BACKGROUND

Hydrocephalus is a neurological disease with an incidence of 0.3-0.7 per 1000 live births in the United States. Ventriculomegaly, periventricular white matter alterations, inflammation, and gliosis are among the neuropathologies associated with this disease. We hypothesized that hippocampus structure and subgranular zone neurogenesis are altered in untreated hydrocephalus and correlate with recognition memory deficits.

METHODS

Hydrocephalus was induced by intracisternal kaolin injections in domestic juvenile pigs (43.6 ± 9.8 days). Age-matched sham controls received similar saline injections. MRI was performed to measure ventricular volume, and/or hippocampal and perirhinal sizes at 14 ± 4 days and 36 ± 8 days post-induction. Recognition memory was assessed one week before and after kaolin induction. Histology and immunohistochemistry in the hippocampus were performed at sacrifice.

RESULTS

The hippocampal width and the perirhinal cortex thickness were decreased (p < 0.05) in hydrocephalic pigs 14 ± 4 days post-induction. At sacrifice (36 ± 8 days post-induction), significant expansion of the cerebral ventricles was detected (p = 0.005) in hydrocephalic pigs compared with sham controls. The area of the dorsal hippocampus exhibited a reduction (p = 0.035) of 23.4% in the hydrocephalic pigs at sacrifice. Likewise, in hydrocephalic pigs, the percentages of neuronal precursor cells (doublecortin+ cells) and neurons decreased (p < 0.01) by 32.35%, and 19.74%, respectively, in the subgranular zone of the dorsal hippocampus. The percentage of reactive astrocytes (vimentin+) was increased (p = 0.041) by 48.7%. In contrast, microglial cells were found to decrease (p = 0.014) by 55.74% in the dorsal hippocampus in hydrocephalic pigs. There was no difference in the recognition index, a summative measure of learning and memory, one week before and after the induction of hydrocephalus.

CONCLUSION

In untreated juvenile pigs, acquired hydrocephalus caused morphological alterations, reduced neurogenesis, and increased reactive astrocytosis in the hippocampus and perirhinal cortex.

Medial prefrontal cortex oxytocin mitigates epilepsy and cognitive impairments induced by traumatic brain injury through reducing neuroinflammation in mice

Traumatic brain injury (TBI) is a major risk factor to develop epilepsy and cognitive impairments. Neuropeptide oxytocin has been previously evidenced to produce antiepileptic effects. However, the involvement of central oxytocin in TBI-induced epileptic status and cognitive dysfunctions is not fully elucidated. In this study, we aim to investigate the role of oxytocin on a TBI model followed by seizure induction to clarify whether the epilepsy and cognitive deficits could be mitigated by oxytocin. TBI was established by weight drop and epileptic behaviors were induced by pentylenetetrazole (PTZ) injection in mice. Moreover, oxytocin was microinjected into the medial prefrontal cortex (mPFC) to observe the effects on the epilepsy and cognition. The blood-brain barrier (BBB) function and the neuroinflammation were measured by Evans Blue staining and enzyme-linked immunosorbent assays, respectively. Mice exposed to TBI demonstrate increased vulnerability to PTZ-mediated seizures and cognitive disturbances with a decrease in peripheral and brain oxytocin levels. Additionally, TBI reduces oxytocin, disrupts the BBB permeability and triggers neuroinflammation in mPFC in PTZ-treated mice. Intra-mPFC oxytocin simultaneously mitigates epilepsy and cognitive impairments. Finally, oxytocin restores BBB integrity and reduces mPFC inflammation in PTZ-treated TBI mice. These findings showed that intra-mPFC oxytocin suppressed the seizure vulnerability and cognitive deficits in TBI mice. The normalization of BBB integrity and inhibition of neuroinflammation may be involved in the antiepileptic and cognition-improved effects of oxytocin, suggesting that targeting inflammatory procedure in mPFC may decrease the risk to develop epilepsy and cognitive impairments in individuals previously experienced TBI.

Inflammatory Markers as Predictors of Shunt Dependency and Functional Outcome in Patients with Aneurysmal Subarachnoid Hemorrhage

The mechanisms underlying post-hemorrhagic hydrocephalus (PHH) development following subarachnoid hemorrhage (SAH) are not fully understood, which complicates informed clinical decisions regarding the duration of external ventricular drain (EVD) treatment and prevents the prediction of shunt-dependency in the individual patient. The aim of this study was to identify potential inflammatory cerebrospinal fluid (CSF) biomarkers of PHH and, thus, shunt-dependency and functional outcome in patients with SAH. This study was a prospective observational study designed to evaluate inflammatory markers in ventricular CSF. In total, 31 Patients with SAH who required an EVD between June 2019 and September 2021 at the Department of Neurosurgery, Rigshospitalet, Copenhagen, Denmark, were included. CSF samples were collected twice from each patient and analyzed for 92 inflammatory markers via proximity extension assay (PEA), and the prognostic ability of the markers was investigated. In total, 12 patients developed PHH, while 19 were weaned from their EVD. Their 6-month functional outcome was determined with the modified Rankin Scale. Of the 92 analyzed inflammatory biomarkers, 79 were identified in the samples. Seven markers (SCF, OPG, LAP TGFβ1, Flt3L, FGF19, CST5, and CSF1) were found to be predictors of shunt dependency, and four markers (TNFα, CXCL5, CCL20, and IL8) were found to be predictors of functional outcome. In this study, we identified promising inflammatory biomarkers that are able to predict (i) the functional outcome in patients with SAH and (ii) the development of PHH and, thus, the shunt dependency of the individual patients. These inflammatory markers may have the potential to be employed as predictive biomarkers of shunt dependency and functional outcome following SAH and could, as such, be applied in the clinic.

Elevated HMGB1 and sRAGE levels in cerebrospinal fluid of aneurysmal subarachnoid hemorrhage patients

BACKGROUND

Neuroinflammation after aneurysmal subarachnoid hemorrhage (aSAH) leads to poor outcome of patients. High mobility group box 1 (HMGB1) contributes to inflammation through binding to receptors for advanced glycation end-products (RAGE) in various diseases. We aimed to determine the production of these two factors after aSAH and their relationship with clinical features.

METHODS

HMGB1 and soluble RAGE (sRAGE) levels in cerebrospinal fluid (CSF) of aSAH patients and controls were measured, and their temporal courses were observed. The correlation between early concentrations (days 1-3) and clinical symptoms assessed by disease severity scores, neuroinflammation estimated by CSF IL-6 levels, as well as prognosis evidenced by delayed cerebral ischemia (DCI) and 6-month adverse outcome was investigated. Finally, combined analysis of early levels for predicting prognosis was confirmed.

RESULTS

CSF HMGB1 and sRAGE levels were higher in aSAH patients than in controls (P < 0.05), and the levels decreased from higher early to lower over time. Their early concentrations were positively associated with disease severity scores, IL-6 levels, DCI and 6-month poor outcome (P < 0.05). HMGB1 ≥ 6045.5 pg/ml (OR = 14.291, P = 0.046) and sRAGE ≥ 572.0 pg/ml (OR = 13.988, P = 0.043) emerged as independent predictors for DCI, while HMGB1 ≥ 5163.2 pg/ml (OR = 7.483, P = 0.043) and sRAGE ≥ 537.3 pg/ml (OR = 12.653, P = 0.042) were predictors for 6-month poor outcome. Combined analysis of them improved predictive values of adverse prognosis.

CONCLUSION

CSF HMGB1 and sRAGE levels of aSAH patients were increased early and then varied dynamically, which might act as potential biomarkers for poor outcome, especially when co-analyzed.

Clustering of serum biomarkers involved in post-aneurysmal subarachnoid hemorrhage (aSAH) complications

Post-aSAH sequela is characterized by the onset of life-threatening complications along with the upregulated underlying inflammation. Cerebral vasospasm (CVS) is one of the most frequent complication after aSAH, which contributes majorly to delayed cerebral ischemia and poor clinical outcome. The objective of this study was to identify the clusters of serum biomarkers that are associated with cerebral vasospasm (CVS) after suffering from aneurysmal subarachnoid hemorrhage (aSAH). In this single-center study, serum concentrations of 10 potential biomarkers, together with clinical and demographic parameters, for 66 aSAH patients were recorded within 24 h after aSAH. The dataset was split into a training set (43 patients) and a validation set. Correlation heatmaps for both datasets were computed. Variables with inconsistent correlations on the two subsets were excluded. Clusters of relevant biomarkers were identified on the complete set, separately for patients who developed post-aSAH CVS and those who did not. Two clusters were found to be specific for patients who suffered from CVS: mitochondrial gene fragments (cytochrome B (Cyt-B), cytochrome C oxidase subunit-1 (Cox-1), displacement loop (D-loop), and IL-23, and the other one, containing IL-6, IL-10, age, and Hunt and Hess score. Clusters of serum biomarkers, analyzed within 24 h of the onset of aSAH, days before the CVS development, are expressed differently in patients suffering from post-aSAH CVS, compared to patients without CVS. This suggests that these biomarkers may be involved in the pathophysiological processes leading to CVS and may be used as its early predictors. These interesting findings are potentially highly relevant for the management of CVS and call for validation on a larger sample of patients.

Fight INflammation to Improve outcome after aneurysmal Subarachnoid HEmorRhage (FINISHER) trial: Study protocol for a randomized controlled trial

RATIONALE

Aneurysmal subarachnoid hemorrhage (SAH) has high morbidity and mortality. While the primary injury results from the initial bleeding cannot currently be influenced, secondary injury through vasospasm and delayed cerebral ischemia worsens outcome and might be a target for interventions to improve outcome. To date, beside the aneurysm treatment to prevent re-bleeding and the administration of oral nimodipine, there is no therapy available, so novel treatment concepts are needed. Evidence suggests that inflammation contributes to delayed cerebral ischemia and poor outcome in SAH. Some studies suggest a beneficial effect of anti-inflammatory glucocorticoids, but there are no data from randomized controlled trials examining the efficacy of glucocorticoids. Therefore, current guidelines do not recommend the use of glucocorticoids in SAH.

AIM

The Fight INflammation to Improve outcome after aneurysmal Subarachnoid HEmorRhage (FINISHER) trial aims to determine whether dexamethasone improves outcome in a clinically relevant endpoint in SAH patients.

METHODS AND DESIGN

FINISHER is a multicenter, prospective, randomized, double-blinded, placebo-controlled clinical phase III trial which is testing the outcome and safety of anti-inflammatory treatment with dexamethasone in SAH patients.

SAMPLE SIZE ESTIMATES

In all, 334 patients will be randomized to either dexamethasone or placebo within 48 h after SAH. The dexamethasone dose is 8 mg tds for days 1-7 and then 8 mg od for days 8-21.

STUDY OUTCOME

The primary outcome is the modified Rankin Scale (mRS) at 6 months, which is dichotomized to favorable (mRS 0-3) versus unfavorable (mRS 4-6).

DISCUSSION

The results of this study will provide the first phase III evidence as to whether dexamethasone improves outcome in SAH.

Cytokines and subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) remains a potentially devastating cerebrovascular disease with a high morbidity and mortality rate, irrespective of treatment. The disease still has a 40-50% mortality rate with a 70% rate of cerebral vasospasm in those patients. The release of cytokines has been implicated in the development and progression of SAH. In this paper, we will explore the role of cytokines in aneurysmal subarachnoid hemorrhage (aSAH), including their effects on the inflammatory response, cerebral vasospasm, blood-brain barrier disruption, and neuronal damage. We also identify the role of the glymphatic system in progression of aSAH. The review will also briefly touch upon current research on potential therapeutic targets aimed at modulating cytokine activity in patients with aSAH. This review aims to give an in-depth review of the cytokines involved in aSAH and serve as a catalyst to research directed towards treatment options for aSAH.

Poor expression of miR-195-5p can assist the diagnosis of cerebral vasospasm after subarachnoid hemorrhage and predict adverse outcomes

OBJECTIVE

Patients with spontaneous subarachnoid hemorrhage (SAH) may develop refractory arterial cerebral vasospasm (CVS), which is the leading cause of death in SAH patients. This study explored the clinical diagnostic value of serum miR-195-5p levels in CVS after SAH (SAH + CVS) and its relationship with the prognosis of SAH + CVS.

METHODS

A total of 110 patients with spontaneous SAH were divided into the SAH group (N = 62) and SAH + CVS group (N = 58), with 60 healthy subjects as controls. The clinical data of blood glucose, blood sodium fluctuation, and serum lactic acid were recorded. miR-195-5p serum level was detected by RT-qPCR and its diagnostic value on SAH + CVS was analyzed by receiver operating characteristic curve. Serum levels of PDGF/IL-6/ET-1 and their correlation with miR-195-5p were analyzed using RT-qPCR, enzyme-linked immunosorbent assay, and Pearson's method. The patient prognosis was evaluated by Glasgow Outcome Scale. The effect of miR-195-5p levels on adverse prognosis was analyzed by Kaplan-Meier method and Cox regression analysis.

RESULTS

miR-195-5p was lowly expressed in the serum of SAH patients and lower in SAH + CVS patients. Serum miR-195-5p level assisted the diagnosis of SAH and SAH + CVS and was negatively correlated with PDGF/IL-6/ET-1 levels and was an independent risk factor together with ET-1 and blood glucose for SAH + CVS. miR-195-5p low expression predicted a higher cumulative incidence of adverse outcomes and was an independent predictor of adverse outcomes.

CONCLUSION

Poor expression of miR-195-5p can assist the diagnosis of SAH + CVS and predict higher adverse outcomes.

Inflammation and immune cell abnormalities in intracranial aneurysm subarachnoid hemorrhage (SAH): Relevant signaling pathways and therapeutic strategies

Intracranial aneurysm subarachnoid hemorrhage (SAH) is a cerebrovascular disorder associated with high overall mortality. Currently, the underlying mechanisms of pathological reaction after aneurysm rupture are still unclear, especially in the immune microenvironment, inflammation, and relevant signaling pathways. SAH-induced immune cell population alteration, immune inflammatory signaling pathway activation, and active substance generation are associated with pro-inflammatory cytokines, immunosuppression, and brain injury. Crosstalk between immune disorders and hyperactivation of inflammatory signals aggravated the devastating consequences of brain injury and cerebral vasospasm and increased the risk of infection. In this review, we discussed the role of inflammation and immune cell responses in the occurrence and development of aneurysm SAH, as well as the most relevant immune inflammatory signaling pathways [PI3K/Akt, extracellular signal-regulated kinase (ERK), hypoxia-inducible factor-1α (HIF-1α), STAT, SIRT, mammalian target of rapamycin (mTOR), NLRP3, TLR4/nuclear factor-κB (NF-κB), and Keap1/nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/ARE cascades] and biomarkers in aneurysm SAH. In addition, we also summarized potential therapeutic drugs targeting the aneurysm SAH immune inflammatory responses, such as nimodipine, dexmedetomidine (DEX), fingolimod, and genomic variation-related aneurysm prophylactic agent sunitinib. The intervention of immune inflammatory responses and immune microenvironment significantly reduces the secondary brain injury, thereby improving the prognosis of patients admitted to SAH. Future studies should focus on exploring potential immune inflammatory mechanisms and developing additional therapeutic strategies for precise aneurysm SAH immune inflammatory regulation and genomic variants associated with aneurysm formation.

Inflammatory Response and Immune Regulation in Brain-Heart Interaction after Stroke

Cerebrocardiac syndrome (CCS) is one of the secondary myocardial injuries after stroke. Cerebrocardiac syndrome may result in a poor prognosis with high mortality. Understanding the mechanism of the brain-heart interaction may be crucial for clinical treatment of pathological changes in CCS. Accumulating evidence suggests that the inflammatory response is involved in the brain-heart interaction after stroke. Systemic inflammatory response syndrome (SIRS) evoked by stroke may injure myocardial cells directly, in which the interplay between inflammatory response, oxidative stress, cardiac sympathetic/parasympathetic dysfunction, and splenic immunoregulation may be also the key pathophysiology factor. This review article summarizes the current understanding of inflammatory response and immune regulation in brain-heart interaction after stroke.

The pathogenesis of idiopathic normal pressure hydrocephalus based on the understanding of AQP1 and AQP4

Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder without a recognized cause. Aquaporins (AQPs) are transmembrane channels that carry water through cell membranes and are critical for cerebrospinal fluid circulation and cerebral water balance. The function of AQPs in developing and maintaining hydrocephalus should be studied in greater detail as a possible diagnostic and therapeutic tool. Recent research indicates that patients with iNPH exhibited high levels of aquaporin 1 and low levels of aquaporin 4 expression, suggesting that these AQPs are essential in iNPH pathogenesis. To determine the source of iNPH and diagnose and treat it, it is necessary to examine and appreciate their function in the genesis and maintenance of hydrocephalus. The expression, function, and regulation of AQPs in iNPH are reviewed in this article, in order to provide fresh targets and suggestions for future research.

Investigation and modulation of interleukin-6 following subarachnoid hemorrhage: targeting inflammatory activation for cerebral vasospasm

Background

Cerebral vasospasm (CV) can contribute to significant morbidity in subarachnoid hemorrhage (SAH) patients. A key unknown is how CV induction is triggered following SAH.

Methods

Human aneurysmal blood and cerebral spinal fluid were collected for evaluation. To confirm mechanism, c57/bl6 wild type and c57/bl6 IL-6 female knockout (KO) mice were utilized with groups: saline injected, SAH, SAH + IL-6 blockade, SAH IL-6 KO, SAH IL-6 KO + IL-6 administration, SAH + p-STAT3 inhibition. Dual-labeled microglia/myeloid mice were used to show myeloid diapedesis. For SAH, 50 μm blood was collected from tail puncture and administered into basal cisterns. IL-6 blockade was given at various time points. Various markers of neuroinflammation were measured with western blot and immunohistochemistry. Cerebral blood flow was also measured. Vasospasm was measured via cardiac injection of India ink/gelatin. Turning test and Garcia’s modified SAH score were utilized. P < 0.05 was considered significant.

Results

IL-6 expression peaked 3 days following SAH (p < 0.05). Human IL-6 was increased in aneurysmal blood (p < 0.05) and in cerebral spinal fluid (p < 0.01). Receptor upregulation was periventricular and perivascular. Microglia activation following SAH resulted in increased caveolin 3 and myeloid diapedesis. A significant increase in BBB markers endothelin 1 and occludin was noted following SAH, but reduced with IL-6 blockade (p < 0.01). CV occurred 5 days post-SAH, but was absent in IL-6 KO mice and mitigated with IL-6 blockade (p < 0.05). IL-6 blockade, and IL-6 KO mitigated effects of SAH on cerebral blood flow (p < 0.05). SAH mice had impaired performance on turn test and poor modified Garcia scores compared to saline and IL-6 blockade. A distinct microglia phenotype was noted day 5 in the SAH group (overlap coefficients r = 0.96 and r = 0.94) for Arg1 and iNOS, which was altered by IL-6 blockade. Day 7, a significant increase in toll-like receptor 4 and Stat3 was noted. This was mitigated by IL-6 blockade and IL-6 KO, which also reduced Caspase 3 (p < 0.05). To confirm the mechanism, we developed a p-STAT3 inhibitor that targets the IL-6 pathway and this reduced NFΚB, TLR4, and nitrotyrosine (p < 0.001). Ventricular dilation and increased Tunel positivity was noted day 9, but resolved by IL-6 blockade (p < 0.05).

Conclusion

Correlation between IL-6 and CV has been well documented. We show that a mechanistic connection exists via the p-STAT3 pathway, and IL-6 blockade provides benefit in reducing CV and its consequences mediated by myeloid cell origin diapedesis.

Graphical abstract

Early Enteral Nutrition Can Reduce Incidence of Postoperative Hydrocephalus in Patients with Severe Hypertensive Intracerebral Hemorrhage

BACKGROUND Hydrocephalus secondary to hypertensive intracerebral hemorrhage (HICH) dramatically affects the prognosis. Early enteral nutrition (EN) is beneficial to severe HICH patients, but the impact of early EN administration on hydrocephalus remains unknown. This study aimed to explore the predictors for hydrocephalus occurrence after HICH, with special focus on the effect of early EN application. MATERIAL AND METHODS We retrospectively analyzed 146 patients with severe HICH who underwent microsurgery between January 2014 and October 2019 in our department. Patients were divided into early EN (≤48 h) and delayed EN (>48 h) group according to the time-point of EN administration. The diagnosis of hydrocephalus was confirmed by both radiological evaluation and an Evan index method. Diagnosis confirmed within 2 weeks after HICH was identified as acute hydrocephalus, otherwise, it was considered as chronic hydrocephalus. RESULTS Twenty-seven patients experienced acute hydrocephalus, while 20 patients developed chronic hydrocephalus. Low preoperative Glasgow coma scale (GCS), subarachnoid hemorrhage (SAH), intraventricular hemorrhage (IVH), delayed EN administration, high levels of postoperative white blood cell, neutrophil, neutrophil-to-lymphocyte ratio, C-reactive protein (CRP), and lactate dehydrogenase were positively related to the occurrence of chronic hydrocephalus (p<0.05), while only IVH was correlated with acute hydrocephalus occurrence (p<0.05). In addition, a multivariate analysis demonstrated that preoperative GCS, SAH, IVH, and early EN administration (p<0.05) were independent predictors for chronic hydrocephalus occurrence. CONCLUSIONS Early EN administration, SAH, IVH, and preoperative GCS were associated with the occurrence of chronic hydrocephalus in severe HICH patients. Early EN administration may inhibit the inflammatory response of brain-gut axis, which in turn reduces chronic hydrocephalus occurrence.

A Systematic Review of Inflammatory Cytokine Changes Following Aneurysmal Subarachnoid Hemorrhage in Animal Models and Humans

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe form of stroke that occurs following rupture of a cerebral aneurysm. Acute inflammation and secondary delayed inflammatory responses, both largely controlled by cytokines, work together to create high mortality and morbidity for this group. The trajectory and time course of cytokine change must be better understood in order to effectively manage unregulated inflammation and improve patient outcomes following aSAH. A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three different search phrases ("cytokines and subarachnoid hemorrhage," "cytokine levels and subarachnoid hemorrhage," and "cytokine measurement and subarachnoid hemorrhage") were applied across three databases (PubMed, SCOPUS, and the Cochrane Library). Our procedures returned 856 papers. After application of inclusion/exclusion criteria, 95 preclinical animal studies and 41 clinical studies remained. Across studies, 22 different cytokines had been investigated, 5 different tissue types were analyzed, and 3 animal models were utilized. Three main pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) demonstrated reliable increases following aSAH across the included studies. While this is a promising area of research for potential therapeutics, there are gaps in the knowledge base that bar progress for clinical translation of this information. In particular, there is a need for investigations that explore the systemic inflammatory response following injury in a more diverse number of cytokines, the balance of specific pro-/anti- inflammatory cytokines, and how these biomarkers relate to patient outcomes and recovery over time.

Acquired hydrocephalus is associated with neuroinflammation, progenitor loss, and cellular changes in the subventricular zone and periventricular white matter

BACKGROUND

Hydrocephalus is a neurological disease with an incidence of 80-125 per 100,000 births in the United States. Neuropathology comprises ventriculomegaly, periventricular white matter (PVWM) alterations, inflammation, and gliosis. We hypothesized that hydrocephalus in a pig model is associated with subventricular and PVWM cellular alterations and neuroinflammation that could mimic the neuropathology described in hydrocephalic infants.

METHODS

Hydrocephalus was induced by intracisternal kaolin injections in 35-day old female pigs (n = 7 for tissue analysis, n = 10 for CSF analysis). Age-matched sham controls received saline injections (n = 6). After 19-40 days, MRI scanning was performed to measure the ventricular volume. Stem cell proliferation was studied in the Subventricular Zone (SVZ), and cell death and oligodendrocytes were examined in the PVWM. The neuroinflammatory reaction was studied by quantifying astrocytes and microglial cells in the PVWM, and inflammatory cytokines in the CSF.

RESULTS

The expansion of the ventricles was especially pronounced in the body of the lateral ventricle, where ependymal disruption occurred. PVWM showed a 44% increase in cell death and a 67% reduction of oligodendrocytes. In the SVZ, the number of proliferative cells and oligodendrocyte decreased by 75% and 57% respectively. The decrease of the SVZ area correlated significantly with ventricular volume increase. Neuroinflammation occurred in the hydrocephalic pigs with a significant increase of astrocytes and microglia in the PVWM, and high levels of inflammatory interleukins IL-6 and IL-8 in the CSF.

CONCLUSION

The induction of acquired hydrocephalus produced alterations in the PVWM, reduced cell proliferation in the SVZ, and neuroinflammation.

Elevated CSF inflammatory markers in patients with idiopathic normal pressure hydrocephalus do not promote NKCC1 hyperactivity in rat choroid plexus

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible neurological condition of unresolved etiology characterized by a clinical triad of symptoms; gait disturbances, urinary incontinence, and cognitive deterioration. In the present study, we aimed to elucidate the molecular coupling between inflammatory markers and development of iNPH and determine whether inflammation-induced hyperactivity of the choroidal Na⁺/K⁺/2Cl^- cotransporter (NKCC1) that is involved in cerebrospinal fluid (CSF) secretion could contribute to the iNPH pathogenesis.

METHODS

Lumbar CSF samples from 20 iNPH patients (10 with clinical improvement upon CSF shunting, 10 without clinical improvement) and 20 elderly control subjects were analyzed with the novel proximity extension assay technique for presence of 92 different inflammatory markers. RNA-sequencing was employed to delineate choroidal abundance of the receptors for the inflammatory markers found elevated in the CSF from iNPH patients. The ability of the elevated inflammatory markers to modulate choroidal NKCC1 activity was determined by addition of combinations of rat version of these in ex vivo experiments on rat choroid plexus.

RESULTS

11 inflammatory markers were significantly elevated in the CSF from iNPH patients compared to elderly control subjects: CCL28, CCL23, CCL3, OPG, CXCL1, IL-18, IL-8, OSM, 4E-BP1, CXCL6, and Flt3L. One inflammatory marker, CDCP1, was significantly decreased in iNPH patients compared to control subjects. None of the inflammatory markers differed significantly when comparing iNPH patients with and without clinical improvement upon CSF shunting. All receptors for the elevated inflammatory markers were expressed in the rat and human choroid plexus, except CCR4 and CXCR1, which were absent from the rat choroid plexus. None of the elevated inflammatory markers found in the CSF from iNPH patients modulated the choroidal NKCC1 activity in ex vivo experiments on rat choroid plexus.

CONCLUSION

The CSF from iNPH patients contains elevated levels of a subset of inflammatory markers. Although the corresponding inflammatory receptors are, in general, expressed in the choroid plexus of rats and humans, their activation did not modulate the NKCC1-mediated fraction of choroidal CSF secretion ex vivo. The molecular mechanisms underlying ventriculomegaly in iNPH, and the possible connection to inflammation, therefore remains to be elucidated.

Systemic inflammation alters the neuroinflammatory response: a prospective clinical trial in traumatic brain injury

Background

Neuroinflammation following traumatic brain injury (TBI) has been shown to be associated with secondary injury development; however, how systemic inflammatory mediators affect this is not fully understood. The aim of this study was to see how systemic inflammation affects markers of neuroinflammation, if this inflammatory response had a temporal correlation between compartments and how different compartments differ in cytokine composition.

Methods

TBI patients recruited to a previous randomised controlled trial studying the effects of the drug anakinra (Kineret®), a human recombinant interleukin-1 receptor antagonist (rhIL1ra), were used (n = 10 treatment arm, n = 10 control arm). Cytokine concentrations were measured in arterial and jugular venous samples twice a day, as well as in microdialysis-extracted brain extracellular fluid (ECF) following pooling every 6 h. C-reactive protein level (CRP), white blood cell count (WBC), temperature and confirmed systemic clinical infection were used as systemic markers of inflammation. Principal component analyses, linear mixed-effect models, cross-correlations and multiple factor analyses were used.

Results

Jugular and arterial blood held similar cytokine information content, but brain-ECF was markedly different. No clear arterial to jugular gradient could be seen. No substantial delayed temporal associations between blood and brain compartments were detected. The development of a systemic clinical infection resulted in a significant decrease of IL1-ra, G-CSF, PDGF-ABBB, MIP-1b and RANTES (p < 0.05, respectively) in brain-ECF, even if adjusting for injury severity and demographic factors, while an increase in several cytokines could be seen in arterial blood.

Conclusions

Systemic inflammation, and infection in particular, alters cytokine levels with different patterns seen in brain and in blood. Cerebral inflammatory monitoring provides independent information from arterial and jugular samples, which both demonstrate similar information content. These findings could present potential new treatment options in severe TBI patients, but novel prospective trials are warranted to confirm these associations.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02264-2.

Relationship Between Nutrition Intake and Outcome After Subarachnoid Hemorrhage: Results From the International Nutritional Survey

BACKGROUND

A previous study suggested an association between low caloric intake(CI), negative nitrogen balance, and poor outcome after subarachnoid hemorrhage(SAH). Objective of this multinational, multicenter study was to investigate whether clinical outcomes vary by protein intake(PI) or CI in SAH patients adjusting for the nutritional risk as judged by the modified NUTrition Risk in the Critically Ill (mNUTRIC) score.

METHODS

The International Nutrition Survey(INS) 2007-2014 was utilized to describe the characteristics, outcomes and nutrition use. A subgroup of patients from 2013 and 2014(when NUTRIC score was captured) examined the association between CI and PI and time to discharge alive(TTDA) from hospital using Cox regression models, adjusting for nutrition risk classified by the mNUTRIC score as low(0-4) or high(5-9).

RESULTS

There were 489 SAH patients(57% female with a mean ± SD age 57.5 ± 13.9 years, BMI of 25.9 ± 5.3 kg/m² and APACHE-2 score 19.4 ± 7.0. Majority(85%) received enteral nutrition(EN) only, with a time to initiation of EN of 35.4 ± 35.2 hours. 64% had EN interrupted. Patients received a CI of 14.6 ± 7.1 calories/kg/day and PI 0.7 ± 0.3 grams/kg/day corresponding to 59% and 55% of total prescribed CI and PI respectively. In the 2013 and 2014 subgroup there were 226 SAH patients with a mNUTRIC score of 3.4 ± 1.8. Increased CI and PI were associated with faster TTDA among high mNUTRIC patients(HR per 20% of prescription received = 1.34[95% CI,1.03 -1.76] for CI and 1.44[1.07 -1.93] for PI), but not low mNUTRIC patients(CI: HR = 0.95[0.77 -1.16] PI:0.95[0.78 -1.16]).

CONCLUSIONS

Results from this multicenter study found that SAH patients received under 60% of their prescribed CI and PI. Further, achieving greater CI and PI in hi risk SAH patients was associated with improved TTDA. mNUTRIC serves to identify SAH patients that benefit most from artificial nutrition and efforts to optimize protein and caloric delivery in this subpopulation should be maximized.

Inhibition of neuronal necroptosis mediated by RIP1/RIP3/MLKL provides neuroprotective effects on kaolin-induced hydrocephalus in mice

OBJECTIVES

Necroptosis is widespread in neurodegenerative diseases. Here, we examined necroptosis in the hippocampus and cortex after hydrocephalus and found that a necroptosis pathway inhibitor alleviates necroptosis and provides neuroprotective effects.

MATERIALS AND METHODS

Hydrocephalus was induced in C57BL/6 mice by kaolin. Haematoxylin and eosin (HE), Nissl, PI and Fluoro-Jade B (FJB) staining were used for general observations. Phosphorylated receptor-interacting protein kinase 3 (p-RIP3) and phosphorylated mixed lineage kinase domain-like (p-MLKL) were measured by Western blotting and immunohistochemistry. Scanning electron microscopy (SEM) was used to observe ependymal cilia. Magnetic resonance imaging (MRI) and the Morris water maze (MWM) test were used to assess neurobehavioral changes. Immunofluorescence was used to detect microglial and astrocyte activation. Inflammatory cytokines were measured by Western blotting and RT-PCR.

RESULTS

Obvious pathological changes appeared in the hippocampus and cortex after hydrocephalus, and expression of the necroptosis markers p-RIP3, p-MLKL and inflammatory cytokines increased. Necrostatin-1 (Nec-1) and GSK872 reduced necrotic cell death, attenuated p-RIP3 and p-MLKL levels, slightly improved neurobehaviours and inhibited microglial and astrocyte activation and inflammation.

CONCLUSIONS

RIP1/RIP3/MLKL mediates necroptosis in the cortex and hippocampus in a hydrocephalus mouse model, and Nec-1 and GSK872 have some neuroprotective effects.

Fatty Acid-Binding Protein 3 and CXC-Chemokine Ligand 16 are Associated with Unfavorable Outcome in Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with activation of the inflammatory cascade contributing to unfavorable outcome and secondary complications, such as delayed cerebral ischemia (DCI). Both fatty acid-binding protein 3 (FABP3) and CXC-chemokine ligand 16 (CXCL-16) have been linked to vascular inflammation and cellular death. The authors aimed to assess the 30-day prognostic value of serum levels of FABP3 and CXCL-16 and explore their associations with DCI in aSAH patients.

METHODS

A total of 60 patients with aSAH were prospectively enrolled. Sampling for markers was done at 24 hours after the index event. FABP3 and CXCL-16 serum concentrations were determined by MilliPlex multiplex immunoassay method. The primary endpoint was unfavorable outcome at Day 30 based on the modified Rankin Scale.

RESULTS

Both FABP3 and CXCL-16 levels were significantly elevated in patients with unfavorable outcome compared to those with favorable outcome after aSAH (FABP3: 2133 pg/mL, IQR: 1053-4567 vs. 3773, 3295-13116; p<0.003 and CXCL-16: 384 pg/mL, 313-502 vs. 498, 456-62, p<0.001). The area under the curve (AUC) for serum CXCL-16 levels as a predictor of unfavorable outcome at Day 30 was 0.747 (95% CI =0.622-0.871; p<0.001). Based on binary logistic regression analysis, serum CXCL-16 with a cut-off level >446.7 ng/L independently predicted Day 30 unfavorable outcome with a sensitivity of 81% and a specificity of 62%. Neither CXCL-16 nor FABP3 showed a significant correlation with DCI.

CONCLUSION

Early FABP3 and CXCL-16 levels are significantly associated with poor 30-day outcome in patients with aSAH.

Preclinical and clinical role of interleukin-6 in the development of delayed cerebral vasospasm and neuronal cell death after subarachnoid hemorrhage: towards a potential target therapy?

Delayed cerebral vasospasm (DCVS), early brain injury (EBI), and delayed cerebral ischemia (DCI) are devastating complications after aneurysmal subarachnoid hemorrhage (SAH). Interleukin (IL)-6 seems to be an important interleukin in the inflammatory response after SAH, and many studies describe a strong correlation between IL-6 and worse outcome. The aim of this study was to systematically review preclinical and clinical studies that evaluated systemic and cerebral IL-6 levels after SAH and their relation to DCVS, neuronal cell death, and DCI. We conducted two systematic literature searches using PubMed to identify preclinical and clinical studies evaluating the role of IL-6 after SAH. Suitable articles were selected based on predefined eligibility criteria following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 61 and 30 preclinical and clinical articles, respectively, were included in the systematic reviews. Of the preclinical studies in which IL-6 was measured in cerebrospinal fluid (CSF), parenchyma, and systemically, 100%, 94.4%, and 81.3%, respectively, showed increased expression of IL-6 after SAH. Preclinical results were mirrored by clinical findings in which elevated levels of IL-6 in CSF and plasma were found after SAH, correlating with DCVS, DCI, and worse outcome. Only two preclinical studies analyzed the direct inhibition of IL-6, which resulted in reduced DCVS and neuronal cell death. IL-6 is a marker of intracranial inflammation and plays a role in the pathophysiology of DCVS and DCI after SAH in preclinical animal models and clinical studies. Its inhibition might have therapeutic potential to improve the outcome of SAH patients.

Differential polarization and activation dynamics of systemic T helper cell subsets after aneurysmal subarachnoid hemorrhage (SAH) and during post-SAH complications

Aneurysmal subarachnoid hemorrhage (SAH) is associated with high morbidity and mortality. Devastating post-SAH complications, such as cerebral vasospasm (CVS), delayed cerebral ischemia or seizures to mention a few, are mainly responsible for the poor clinical outcome. Inflammation plays an indispensable role during early brain injury (EBI) and delayed brain injury (DBI) phases over which these complications arise. T helper cells are the major cytokine secreting cells of adaptive immunity that can polarize to multiple functionally unique sub-populations. Here, we investigate different CD4+ T cell subsets during EBI and DBI phases after SAH, and their dynamics during post-SAH complications. Peripheral venous blood from 15 SAH patients during EBI and DBI phases, was analyzed by multicolour flowcytometry. Different subsets of CD3+ CD4+ T cells were characterized by differential cell surface expression of CXCR3 and CCR6 into Th1, Th2, Th17, whereas Tregs were defined by CD25^hiCD127^lo. The analysis of activation states was done by the expression of stable activation markers CD38 and HLA-DR. Interestingly, compared to healthy controls, Tregs were significantly increased during both EBI and DBI phases. Different activation states of Tregs showed differential significant increase during EBI and DBI phases compared to controls. HLA-DR− CD38+ Tregs were significantly increased during DBI phase compared to EBI phase in SAH patients developing CVS, seizures and infections. However, HLA-DR− CD38− Tregs were significantly reduced during EBI phase in patients with cerebral ischemia (CI) compared to those without CI. HLA-DR− CD38− Th2 cells were significantly increased during EBI phase compared to controls. A significant reduction in Th17/Tregs and HLA-DR− CD38+ Th17/Tregs ratios was observed during both EBI and DBI phases compared to controls. While HLA-DR− CD38− Th17/Tregs and HLA-DR− CD38− Th1/Th2 ratios were impaired only during EBI phase compared to controls. In conclusion, CD4+ T cell subsets display dynamic and unique activation patterns after SAH and during the course of the manifestation of post-SAH complications, which may be helpful for the development of precision neurovascular care. However, to claim this, confirmatory studies with larger patient cohorts, ideally from different ethnic backgrounds, are required. Moreover, our descriptive study may be the grounds for subsequent lab endeavors to explore the underlying mechanisms of our observations.

The Role of the Blood Neutrophil-to-Lymphocyte Ratio in Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is an important type of stroke with the highest rates of mortality and disability. Recent evidence indicates that neuroinflammation plays a critical role in both early brain injury and delayed neural deterioration after aSAH, contributing to unfavorable outcomes. The neutrophil-to-lymphocyte ratio (NLR) is a peripheral biomarker that conveys information about the inflammatory burden in terms of both innate and adaptive immunity. This review summarizes relevant studies that associate the NLR with aSAH to evaluate whether the NLR can predict outcomes and serve as an effective biomarker for clinical management. We found that increased NLR is valuable in predicting the clinical outcome of aSAH patients and is related to the risk of complications such as delayed cerebral ischemia (DCI) or rebleeding. Combined with other indicators, the NLR provides improved accuracy for predicting prognosis to stratify patients into different risk categories. The underlying pathophysiology is highlighted to identify new potential targets for neuroprotection and to develop novel therapeutic strategies.

A Prospective Study of Novel Therapeutic Targets Interleukin 6, Tumor Necrosis Factor α, and Interferon γ as Predictive Biomarkers for the Development of Posttraumatic Epilepsy

Background

Posttraumatic epilepsy (PTE) is a serious and debilitating consequence of traumatic brain injury (TBI). Sometimes, the management of PTE becomes a challenging task on account of its resistance to existing antiepileptic drugs and often contributes to poor functional and psychosocial outcomes after TBI. We investigated the role of inflammatory markers interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and interferon γ (INF-γ) in predicting the development of PTE.

Methods

A prospective analysis was performed of 254 patients who were admitted with head injury to our hospital, 35 of whom had posttraumatic epilepsy (32 males and 3 females); 30 adults (28 men, 2 women) with a similar demographic profile were selected randomly as control individuals. Blood levels of TNF-α, IL-6, and INF-γ were evaluated in all participants.

Results

IL-6 levels were significantly higher in the PTE group (121.36 pg/mL; standard deviation [SD], 89.23) than in the nonseizure group (65.30 pg/mL; SD, 74.75; P = 0.01), whereas there was no significant difference between the seizure group (11.42 pg/mL; SD, 7.84) and the nonseizure groups (10.58 pg/mL; SD, 7.84) in terms of TNF-α level (P = 0.343). The level of INF-γ in the seizure group tended to be higher (mean, 1.88 pg/mL, SD, 2.13 in seizure group vs. 1.10 pg/mL, SD, 1.45 in the nonseizure group); however, no statistically significant difference was detected among the 2 groups (P = 0.09).

Conculsions

Posttraumatic epilepsy has a strong association with an increased level of IL-6 in the blood. INF-γ may or may not be associated with PTE. However, TNF-α was not associated with PTE.

Interleukin-6 in Cerebrospinal Fluid Small Extracellular Vesicles as a Potential Biomarker for Prognosis of Aneurysmal Subarachnoid Haemorrhage

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe form of stroke characterized by high rates of mortality and disability. Identifying circulating biomarkers is helpful to improve outcomes. In this study, for the first time, we identify interleukin-6 (IL-6) in cerebrospinal fluid (CSF) small extracellular vesicles (sEVs) as potential biomarkers for prognosis of aSAH.

METHODS

We extracted small extracellular vesicles from the CSF of 103 aSAH patients and 40 healthy controls in a prospective observational study. Subsequently, we measured IL-6sEVs levels using an enzyme-linked immunosorbent assay. Results were statistically analyzed to determine the function of IL-6sEVs for disease monitoring of aSAH.

RESULTS

CSF IL-6 sEVs showed distinct pattern differences between healthy controls and aSAH patients. The concentration of IL-6sEVs in CSF is significantly correlated with the severity of aSAH patients. The areas under the receiver operating characteristic curves of IL-6sEVs for identifying severe aSAH patient from aSAH patients were 0.900. After multivariate logistic regression analysis, IL-6sEVs were associated with neurological outcome at 1 year. IL-6sEVs levels were greater and positively associated with disease processes and outcome.

CONCLUSION

There is a neuroinflammatory cascade in aSAH patients. IL-6sEVs in CSF may be a biomarker for the progression of aSAH.

Increased level of LIGHT/TNFSF14 is associated with survival in aneurysmal subarachnoid hemorrhage

OBJECTIVES

Multiple cytokines have been implicated in aneurysmal subarachnoid hemorrhage (aSAH), but tumor necrosis factor superfamily 14 (LIGHT/TNFSF14) and oncostatin-M (OSM) have not been previously explored.

AIMS OF THE STUDY

The primary objective of this study was to examine the relationship between TNFSF14 and OSM levels and survival. Our secondary goal was to investigate a potential association between these markers and the incidence of delayed cerebral ischemia (DCI).

MATERIALS & METHODS

We consecutively recruited 60 patients with a clinical diagnosis of aSAH. LIGHT/TNFSF14 and OSM serum concentrations were determined by ELISA. The primary endpoint was survival at Day 30, while development of DCI was assessed as secondary outcome.

RESULTS

Patients had significantly higher levels of both markers than the control group (median of LIGHT: 18.1 pg/ml vs. 7 pg/ml; p = 0.01; median of OSM: 10.3 pg/ml vs. 2.8 pg/ml, p < 0.001). Significantly lower serum level of LIGHT/TNFSF14 was found in nonsurviving patients (n = 9) compared with survivors (n = 51; p = 0.011). Based on ROC analysis, serum LIGHT/TNFSF14 with a cutoff value of >7.95 pg/ml predicted 30-day survival with a sensitivity of 71% and specificity of 78% (Area: 0.763; 95% CI: 0.604-0.921, p = 0.013). In addition, it was also a predictor of DCI with a sensitivity of 72.7% and a specificity of 62.5% (AUC: 0.702; 95% CI: 0.555-0.849, p = 0.018). Based on binary logistic regression analysis, LIGHT/TNFSF14 was found to be independently associated with 30-day mortality, but not with DCI.

CONCLUSION

In this cohort, a higher serum level of LIGHT/TNFSF14 was associated with increased survival of patients with aSAH.

Subarachnoid Hemorrhage and COVID-19: An Analysis of 282,718 Patients

Background

Intracranial hemorrhage (including subarachnoid hemorrhage [SAH]) has been reported in 0.3%–1.2% of patients with coronavirus disease 2019 (COVID-19). However, no study has evaluated the risk of SAH in patients with COVID-19.

Methods

We analyzed data from 62 health care facilities using the Cerner de-identified COVID-19 dataset.

Results

There were 86 (0.1%) and 376 (0.2%) patients with SAH among 85,645 patients with COVID-19 and 197,073 patients without COVID-19, respectively. In the multivariate model, there was a lower risk of SAH in patients with COVID-19 (odds ratio 0.5, 95% confidence interval 0.4–0.7, P < 0.0001) after adjusting for sex, age strata, race/ethnicity, hypertension, and nicotine dependence/tobacco use. The proportions of patients who developed pneumonia (58.1% vs. 21.3%, P < 0.0001), acute kidney injury (43% vs. 27.7%, P = 0.0005), septic shock (44.2% vs. 20.7%, P < 0.0001), and respiratory failure (64.0% vs. 39.1%, P < 0.0001) were significantly higher among patients with SAH and COVID-19 compared with patients without COVID-19. The in-hospital mortality among patients with SAH and COVID-19 was significantly higher compared with patients without COVID-19 (31.4% vs. 12.2%, P < 0.0001).

Conclusions

The risk of SAH was not increased in patients with COVID-19. The higher mortality in patients with SAH and COVID-19 compared with patients without COVID-19 is likely mediated by higher frequency of systemic comorbidities.

Interleukin 6 and Aneurysmal Subarachnoid Hemorrhage. A Narrative Review

Interleukin 6 (IL-6) is a prominent proinflammatory cytokine. Neuroinflammation in general, and IL-6 signaling in particular, appear to play a major role in the pathobiology and pathophysiology of aneurysm formation and aneurysmal subarachnoid hemorrhage (SAH). Most importantly, elevated IL-6 CSF (rather than serum) levels appear to correlate with delayed cerebral ischemia (DCI, “vasospasm”) and secondary (“vasospastic”) infarctions. IL-6 CSF levels may also reflect other forms of injury to the brain following SAH, i.e., early brain damage and septic complications of SAH and aneurysm treatment. This would explain why many researchers have found an association between IL-6 levels and patient outcomes. These findings clearly suggest CSF IL-6 as a candidate biomarker in SAH patients. However, at this point, discrepant findings in variable study settings, as well as timing and other issues, e.g., defining proper clinical endpoints (i.e., secondary clinical deterioration vs. angiographic vasospasm vs. secondary vasospastic infarct) do not allow for its routine use. It is also tempting to speculate about potential therapeutic measures targeting elevated IL-6 CSF levels and neuroinflammation in SAH patients. Corticosteroids and anti-platelet drugs are indeed used in many SAH cases (not necessarily with the intention to interfere with detrimental inflammatory signaling), however, no convincing benefit has been demonstrated yet. The lack of a robust clinical perspective against the background of a relatively large body of data linking IL-6 and neuroinflammation with the pathophysiology of SAH is somewhat disappointing. One underlying reason might be that most relevant studies only report correlative data. The specific molecular pathways behind elevated IL-6 levels in SAH patients and their various interactions still remain to be delineated. We are optimistic that future research in this field will result in a better understanding of the role of neuroinflammation in the pathophysiology of SAH, which in turn, will translate into the identification of suitable biomarkers and even potential therapeutic targets.

Significance of changes in the concentration of inflammatory factors in blood or cerebrospinal fluid in evaluating the severity and prognosis of spontaneous cerebral hemorrhage: A systematic review and meta-analysis

OBJECTIVE

Spontaneous intracerebral hemorrhage (SICH) often leads to severe disability, while inflammation plays an important role in SICH-induced secondary brain injury. The purpose of this study was to investigate the value of inflammatory factors as a means of evaluating the prognosis of SICH and to investigate the relationship between inflammatory factors and the severity and prognosis of SICH.

METHODS

The articles published before November 1 2020 were searched through PubMed, EMBASE, Cochrane library and web of science. Revman5.3 was used, using the inverse variance model to pool the SMD of TNF-a and interleukin concentration.

RESULTS

A total of 25 studies involving 3333 subjects were included in this paper. The concentration of TNF-α in the blood or cerebrospinal fluid of severe SICH patients was significantly higher than that of milder SICH patients or healthy population; SICH patients with high TNF-α concentration had a 1.06 times greater odds of poor outcomes than patients with low TNF-α concentration, odds ratio (OR) = 1.06[95% CI, 1.01-1.12]. The concentration of interleukin-6 (IL-6) in severe SICH patients was significantly higher than that in milder SICH patients; patients with high IL-6 concentration had a 2.61 times greater odds of poor outcomes than patients with low IL-6 concentration, OR = 2.61[95% CI, 1.79-3.80].

CONCLUSIONS

The detection of concentrations of TNF-α and IL-6 in peripheral blood may be helpful for the objective and quantitative assessment of the severity and prognosis of patients with SICH, and have certain significance for the selection of appropriate treatment options.

Clinical Significance of Cytotoxic Lesions of the Corpus Callosum in Subarachnoid Hemorrhage Patients: A Retrospective Analysis

INTRODUCTION

Cytotoxic lesions of the corpus callosum are secondary lesions induced by significant increases in cytokine levels in the brain and are associated with subarachnoid hemorrhage (SAH). However, their clinical significance in SAH patients remains unclear.

METHODS

We retrospectively analyzed SAH patients who were treated in our hospital and evaluated between-group differences in the backgrounds, clinical findings, and outcomes between SAH patients who developed cytotoxic lesions of the corpus callosum and those who did not. We further compared patients who achieved good outcomes with those who had poor outcomes. Multivariate logistic regression analysis was used to identify risk factors for poor clinical outcomes.

RESULTS

We analyzed 159 SAH patients; 17 patients (10.7%) had cytotoxic lesions of the corpus callosum. Patients with cytotoxic lesions of the corpus callosum were more likely to be in a severe condition (World Federation of Neurosurgical Societies grading IV-V: odds ratio [OR], 4.53; 95% confidence interval [95% CI]: 1.60-12.84; p = 0.0042) and have an intraventricular (OR, 5.98; 95% CI: 1.32-27.13; p = 0.0054) or an intraparenchymal hematoma (OR, 3.62; 95% CI: 1.25-10.45; p = 0.023). Patients with cytotoxic lesions of the corpus callosum had a greater propensity of a poor outcome 3 months after onset (modified Rankin Scale score 0-2: OR, 0.22; 95% CI: 0.07-0.66; p = 0.0043). Multivariate analysis confirmed that cytotoxic lesions of the corpus callosum increased the risk of a poor outcome (OR, 4.39; 95% CI: 1.06-18.1; p = 0.037).

DISCUSSION/CONCLUSIONS

The development of cytotoxic lesions of the corpus callosum may be related to the extent of hematomas in SAH patients. Although they are usually reversible lesions, the development of cytotoxic lesions of the corpus callosum may be a predictor of poor outcomes in SAH patients.

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.

Emerging Role of Microglia-Mediated Neuroinflammation in Epilepsy after Subarachnoid Hemorrhage

Epilepsy is a common and serious complication of subarachnoid hemorrhage (SAH), giving rise to increased morbidity and mortality. It's difficult to identify patients at high risk of epilepsy and the application of anti-epileptic drugs (AEDs) following SAH is a controversial topic. Therefore, it's pressingly needed to gain a better understanding of the risk factors, underlying mechanisms and the optimization of therapeutic strategies for epilepsy after SAH. Neuroinflammation, characterized by microglial activation and the release of inflammatory cytokines, has drawn growing attention due to its influence on patients with epilepsy after SAH. In this review, we discuss the risk factors for epilepsy after SAH and emphasize the critical role of microglia. Then we discuss how various molecules arising from pathophysiological changes after SAH activate specific receptors such as TLR4, NLRP3, RAGE, P2X7R and initiate the downstream inflammatory pathways. Additionally, we focus on the significant responses implicated in epilepsy including neuronal excitotoxicity, the disruption of blood-brain barrier (BBB) and the change of immune responses. As the application of AEDs for seizure prophylaxis after SAH remains controversial, the regulation of neuroinflammation targeting the key pathological molecules could be a promising therapeutic method. While neuroinflammation appears to contribute to epilepsy after SAH, more comprehensive experiments on their relationships are needed.

Edema Resolution and Clinical Assessment in Poor-Grade Subarachnoid Hemorrhage: Useful Indicators to Predict Delayed Cerebral Infarctions?

Background: The level of consciousness and cerebral edema are among the indicators that best define the intensity of early brain injury following aneurysmal subarachnoid hemorrhage (aSAH). Although these indicators are usually altered in patients with a poor neurological status, their usefulness for selecting patients at risk of cerebral infarction (CI) is not well established. Furthermore, little is known about the evolution of these indicators during the first week of post-ictal events. Our study focused on describing the association of the longitudinal course of these predictors with CI occurrence in patients with severe aSAH. Methods: Out of 265 aSAH patients admitted consecutively to the same institution, 80 patients with initial poor neurological status (WFNS 4–5) were retrospectively identified. After excluding 25 patients with early mortality, a total of 47 patients who underwent early CT (<3 days) and late CT (<7 days) acquisitions were included in the study. Early cerebral edema and delayed cerebral edema were calculated using the SEBES score, and the level of consciousness was recorded daily during the first week using the Glasgow Coma Scale (GCS). Results: There was a significant improvement in the SEBES (Early-SEBES median (IQR) = 3 (2–4) versus Delayed-SEBES = 2 (1–3); p = 0.001) and in GCS scores (B = 0.32; 95% CI 0.15–0.49; p = 0.001) during the first week. When comparing the ROC curves of Delayed-SEBES vs Early-SEBES as predictors of CI, no significant differences were found (Early-SEBES Area Under the Curve: 0.65; Delayed-SEBES: 0.62; p = 0.17). Additionally, no differences were observed in the relationship between the improvement in the GCS across the first week and the occurrence of CI (p = 0.536). Conclusions: Edema and consciousness level improvement did not seem to be associated with the occurrence of CI in a surviving cohort of patients with severe aSAH. Our results suggest that intensive monitoring should not be reduced in patients with a poor neurological status regardless of an improvement in cerebral edema and level of consciousness during the first week after bleeding.

Interleukin 6 in cerebrospinal fluid is a biomarker for delayed cerebral ischemia (DCI) related infarctions after aneurysmal subarachnoid hemorrhage

Interleukin 6 (IL-6) is a prominent proinflammatory cytokine and has been discussed as a potential biomarker for delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage. In the present study we have analyzed the time course of serum and cerebrospinal fluid (CSF) IL-6 levels in 82 patients with severe aneurysmal subarachnoid hemorrhage (SAH) requiring external ventricular drains in correlation to angiographic vasospasm, delayed cerebral ischemia, secondary infarctions and other clinical parameters. We observed much higher daily mean IL-6 levels (but also large interindividual variations) in the CSF than the serum of the patients with a peak between days 4 and 14 including a maximum on day 5 after SAH. Individual CSF peak levels correlated significantly with DCI (mean day 4–14 peak, DCI: 26,291 ± 24,159 pg/ml vs. no DCI: 16,184 ± 13,163 pg/ml; P = 0.023). Importantly, CSF IL-6 levels differed significantly between cases with DCI and infarctions and patients with DCI and no infarction (mean day 4–14 peak, DCI with infarction: 37,209 ± 26,951 pg/ml vs. DCI, no infarction: 15,123 ± 11,239 pg/ml; P = 0.003), while findings in the latter patient group were similar to cases with no vasospasm (mean day 4–14 peak, DCI, no infarction: 15,123 ± 11,239 vs. no DCI: 15,840 ± 12,979; P = 0.873). Together, these data support a potential role for elevated CSF IL-6 levels as a biomarker for DCI with infarction rather than for DCI in general. This fits well with a growing body of evidence linking neuroinflammation to ischemia and infarction, but (together with the large interindividual variations observed) limits the diagnostic usefulness of CSF IL-6 levels in SAH patients.

Interleukin-6: Important Mediator of Vasospasm Following Subarachnoid Hemorrhage

The correlation of neuroinflammation with the development of cerebral vasospasm following subarachnoid hemorrhage has been well documented in the literature; both clinical and preclinical. The exact mechanisms by which this process occurs, however, are poorly elucidated. Recent evidence indicates that interleukin-6 is not only an important prognostic biomarker for subarachnoid hemorrhage and subsequent vasospasm development but also an integral component in the progression of injury following initial insult. In this review, we briefly highlight other pathways under investigation and focus heavily on what has been discovered regarding the role of interleukin 6 and cerebral vasospasm following subarachnoid hemorrhage. A proposed mechanistic pathway is highlighted in written and graphical format. A discussion regarding the human correlative findings and initial pre-clinical mechanistic studies is addressed. Finally, in the future investigation section, innovative developments and a clear description of areas warranting further scientific inquiry are emphasized. This review will catalyze continued discovery in this area of emerging significance and aid in the quest for effective vasospasm treatment where limited clinical therapeutics currently exist.

Can brain natriuretic peptide, S100b, and interleukin-6 prognosticate the neurological consequences in Egyptian patients presented with supratentorial intracerebral hemorrhage?

Background:

Biomarkers in supratentorial intracerebral hemorrhage (SICH) enhance the prognosis of the disease. This study aimed to assess the prognosticative grade of S100 calcium-binding protein B (S100B), interleukin-6 (IL-6), and the pro-brain natriuretic peptide (pro-BNP) in SICH outcome prediction.

Methods:

Blood samples of 50 SICH patients were analyzed for the biomarkers. The patients were classified into two groups with and without intraventricular hemorrhage (IVH). The following scales including Glasgow Coma Score (GCS), the Barthel index (BI), intracerebral hemorrhage (ICH) score, ICH volume, National Institutes of Health Stroke Scale (NIHSS), Modified Rankin Score (mRS), and length of stay were used to evaluate the severity.

Results:

The severity scores (NIHSS, GCS, BI, mRI) were significantly higher in SICH patients with IVH versus SICH patients without IVH (P = 0.002, 0.008, 0.001, and 0.03, respectively). Serum levels for a pro-BNP and S100b are significantly higher in SICH patients with IVH versus SICH patients without IVH (P = 0.02 and 0.027, respectively). Multivariate correlations between demographic (age), biomarkers panel (IL-6, S100b, and proBNP), and clinical and severity scores (ICH score, ICH volume, length of hospital stay [LOS], BI, mRS, GCS, and NIHSSS) in all studied patients showed a highly significant correlation between ICH score and pro-BNP (P = 0.04). There was a highly significant correlation between LOS and IL-6 (P = 0.003).

Conclusion:

Pro-BNP, IL-6, and S100b are greatly associated with the presence of IVH that, in turn, correlated well with poor clinical outcome measures.

Risk factors for cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage

Introduction

Aneurysmal subarachnoid hemorrhage is a type of spontaneous hemorrhagic stroke, which is caused by a ruptured cerebral aneurysm. Cerebral vasospasm (CVS) is the most grievous complication of subarachnoid hemorrhage (SAH). The aim of this study was to examine the risk factors that influence the onset of CVS that develops after endovascular coil embolization of a ruptured aneurysm.

Materials and methods

The study was designed as a cross-sectional study. The patients included in the study were 18 or more years of age, admitted within a period of 24 h of symptom onset, diagnosed and treated at a university medical center in Serbia during a 5-year period.

Results

Our study showed that the maximum recorded international normalized ratio (INR) values in patients who were not receiving anticoagulant therapy and the maximum recorded white blood cells (WBCs) were strongly associated with cerebrovascular spasm, increasing its chances 4.4 and 8.4 times with an increase of each integer of the INR value and 1,000 WBCs, respectively.

Conclusions

SAH after the rupture of cerebral aneurysms creates an endocranial inflammatory state whose intensity is probably directly related to the occurrence of vasospasm and its adverse consequences.

Dynamic Change in Mean Platelet Volume and Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

Background: The mean platelet volume (MPV) has been shown to predict short-term outcomes in patients who have experienced aneurysmal subarachnoid hemorrhage (aSAH). The purpose of this study was to explore the temporal variation of MPV in patients with aSAH and its relationship to the development of delayed cerebral ischemia (DCI).

Methods: Data from 197 consecutive aSAH patients who were treated at our institution between January 2017 and December 2019 were collected and analyzed. Blood samples to assess MPV were obtained at 1–3, 3–5, 5–7, and 7–9 d after the initial hemorrhage. Univariate and multivariate analyses were performed to investigate whether MPV was an independent predictor of DCI and the receiver operating characteristic (ROC) curve and area under the curve (AUC) were determined.

Results: The MPV values in patients with DCI were significantly higher compared to those without DCI at 1–3, 3–5, 5–7, and 7–9 d after hemorrhage (P < 0.001). The trend for MPV in patients with DCI was increased at first and then decreased. The transition from increases to decreases occurred at 3–5 d after hemorrhage. The optimal cutoff value for MPV to accurately predict DCI was 10.35 fL at 3–5 d after aSAH in our cohort. Furthermore, the MPV observed at 3–5 d was an independent risk factor for DCI [odds ratio (OR) = 4.508, 95% confidence interval (CI): 2.665–7.626, P < 0.001].

Conclusions: MPV is a dynamic variable that occurs during aSAH, and a high MPV at 3–5 days after hemorrhage is associated with the development of DCI.

Postinfectious inflammation in cerebrospinal fluid is associated with nonconvulsive seizures in subarachnoid hemorrhage patients

PURPOSE

It was unclear how nonconvulsive seizures (NCS) occurred after subarachnoid hemorrhage (SAH). The aim of this prospective observational study was to determine the association between cerebrospinal fluid postinfectious inflammation and NCS in patients with SAH.

METHODS

Demographics and parameters were retrieved from pooled data of all SAH patients monitored by continuous electroencephalography (cEEG) in our Stroke-Intensive Care Unit (Stroke-ICU) over six years period. Patients were divided into two groups (NCS group and non-NCS group). According to clinical and cerebrospinal fluid (CSF) parameters, a logistic regression model was used to analyze the association between CSF inflammation and NCS.

RESULTS

The data of 143 SAH patients were analyzed (25 patients with NCS and 118 patients with non-NCS). Median age was 53 years (min - max: 19 years - 90 years). 4.8 % SAH patients were accompanied with NCS. Among these 25 NCS patients, only 2 (8%) had complete control of EEG discharges. After confounders correction, logistic regression analysis showed: SAH patients with older age [P = 0.003, OR = 1.193, 95 %CI (1.062-1.341)], intracranial infections [P = 0.000, OR = 171.939, 95 %CI (18.136-1630.064)] and higher increased modified Fisher Scale (mFS) [P = 0.003, OR = 8.884, 95 %CI (2.125-37.148)] were more likely to develop NCS; furthermore, a high level of CSF interleukin-6 (IL-6) was an independent risk factor for NCS [P = 0.000, OR = 1.015, 95 %CI (1.010-1.020)], with a threshold of 164.9 pg/mL (sensitivity = 0.84, specificity = 0.96). Compared with non-NCS patients, NCS patients were more likely to have poor Glasgow outcome scale (GOS) (1-3) at 3 months after discharge (88 %).

CONCLUSIONS

SAH patients with NCS were associated with poor neurological prognosis. With the increase of age and mFS, these patients were more likely to develop NCS. As an intracranial infective mark, a high level of CSF IL-6 was an independent risk factor for NCS. For brain protection of severe brain injury after SAH, we should focus on the increasingly important role of inflammatory response.