Clinical Value of Inflammatory Cytokines in Patients with Aneurysmal Subarachnoid Hemorrhage

Neuroinflammatory response after subarachnoid hemorrhage: A review of possible treatment targets

A serious neurosurgical emergency, subarachnoid hemorrhage (SAH) is characterized by vascular and neuropathy, as well as complex pathological mechanisms like vascular lesions, inflammatory responses, and nerve cell damage. The inflammatory response is an essential aspect of SAH's pathophysiology, causing the release of a number of inflammatory mediators and oxidative stress products like TNF-α, MCP-1, MMPs, and so on, which either directly or indirectly contribute to the development of SAH.It has recently been discovered that some antibodies against inflammatory mediators, antioxidant stress, botanicals, and traditional Chinese medicine decrease the inflammatory response of SAH. Additionally, certain biomarkers linked to inflammation may serve as a foundation for clinical diagnosis.Although these mechanisms are still not completely understood, we can explore potential therapeutic targets by studying the role of inflammatory responses and bioactive molecules in the formation of SAH.

Early changes in inflammation-related proteins in the cerebrospinal fluid and plasma of patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is a relatively uncommon but high mortality form of stroke that can result in long-lasting disability. A better understanding of key neuroinflammatory changes during the early phase (<72 h) may provide potential avenues of treatment.

METHODS

In an attempt to understand these early changes, we recruited 7 aSAH patients for profiling of longitudinal plasma and cerebrospinal fluid (CSF) proteins at up to 72 h post injury. We additionally compared this to control plasma obtained previously from healthy elderly volunteers. Using the Alamar Biosciences NULISAseq platform, we obtained a comprehensive picture of early peripheral and central inflammatory changes after injury.

RESULTS

This study demonstrated very early plasma changes across 107 inflammatory proteins, 22 of which showed significant correlations between plasma and CSF. Of these, CXCL12, IL-15, and SAA1 are detectably elevated <24 h in plasma, significantly correlated with CSF levels, and altered as a function of aSAH progression over time during this early phase.

CONCLUSION

This study demonstrates the feasibility of measuring a large number of inflammatory proteins in CSF and plasma from aSAH patients soon after injury. Despite the small sample size and limitations of the control group, we identified several previously reported "hits" that may offer prognostic utility and/or therapeutic potential for aSAH patients: CXCL12, IL-15, and SAA1.

Long-Term Cognitive Decline After Subarachnoid Hemorrhage: Pathophysiology, Management, and Future Directions

Subarachnoid hemorrhage is a critical neurological condition accounting for about 5% of all strokes, and survivors experience long-term cognitive deterioration and increased risk of dementia. The major processes involved in such decline include early brain injury, delayed cerebral ischemia, neuroinflammation, superficial siderosis, and hydrocephalus. These have emerging treatments that offer promise for the mitigation of effects such as inflammation, iron chelation, and microvascular dysfunction. Genetic predispositions have been associated with post-subarachnoid hemorrhage cognitive outcomes and emphasize a role for personalized care strategies. Management techniques reviewed include long-term cognitive health, such as endovascular coiling and surgical clipping. Other rehabilitation strategies that enhance cognitive reserve and pharmacological interventions are discussed about improving the quality of life in survivors. The review highlights the need for further research into targeted therapies, genetic markers, and innovative approaches to prevent cognitive decline, ultimately aiming to optimize long-term outcomes for individuals affected by subarachnoid hemorrhage.

GPR30 Inhibits Neuronal Apoptosis After Subarachnoid Hemorrhage by Activating the Wnt/β-Catenin Pathway in a m6A-dependent Manner

Neuronal apoptosis is associated with early brain injury after subarachnoid hemorrhage (SAH). In this study, the regulatory effects of GPR30 on neuronal apoptosis after SAH, METTL14 expression, and the Wnt/β-catenin pathway were investigated. SAH models were constructed in vitro in neurons and in vivo in rats. We found that the GPR30 protein was downregulated in OxyHB-stimulated neurons and SAH rat brain tissue. The GPR30 agonist G1 decreased iNOS levels and apoptosis in OxyHB-stimulated neurons. G1 increased m6A levels in OxyHB-stimulated neurons, increased the expression of METTL14 and Bcl-2, and reduced Caspase-3 and Bax levels. The GPR30 inhibitor G15 had the opposite effect as G1. METTL14 overexpression increased m6A levels in OxyHB-stimulated neurons; increased the expression of METTL14, Wnt1, β-catenin, and Bcl-2; decreased Caspase-3 and Bax levels; and inhibited apoptosis. The Wnt inhibitor IWR-1 abrogated the effects of METTL14 overexpression in OxyHB-stimulated neurons. In vivo, the results revealed that G1 decreased the mNSS, cerebral edema score, and caspase-3, IL-6, IL-1β, Bax, and p-β-catenin expression; inhibited apoptosis and nitric oxide production; and increased GPR30, IFN-γ, TGF-β1, METTL14, Wnt1, and β-catenin expression. G15 had the opposite effect of G1. METTL14 knockdown abrogated the effects of G1 in SAH model rats. Our results suggest that GPR30 inhibits neuronal apoptosis after SAH via Wnt/β-catenin pathway regulation and METTL14-mediated m6A modification, providing a new therapeutic target for SAH.

Association of serum glucose/potassium index levels with poor long-term prognosis in patients with Aneurysmal Subarachnoid Hemorrhage

INTRODUCTION

The glucose/potassium index (GPI) has been reported as a predictor biomarker of in-hospital complications in patients with aneurysmal subarachnoid hemorrhage (aSAH).

OBJECTIVES

To determine the association between GPI and functional outcome at 3-6 months after discharge in patients diagnosed with aSAH in a Peruvian referral hospital during 2018-2021.

MATERIALS AND METHODS

We conducted a retrospective cohort observational study with a secondary database in patients with aSAH during 2018-2021 in a Peruvian referral hospital. We evaluated the relationship between GPI values and motor functionality from 3 m to 6 months post-discharge, using a Poisson family generalized linear model with Log link function and robust variance according to categorization of good and poor outcome. We considered a value of p<0.05 as statistically significant. We used restricted cubic splines with five nodes to evaluate the linear correlation between the 2 main variables.

RESULTS

212 patients were included in the analysis. 21.1 % and 19.3 % had poor outcome at 3 and 6 months after discharge, respectively. Multivariate analysis showed that GPI was not associated with poor outcome at 3 (RR=0.999; 95 %CI=0.979-1.018) or 6 months after discharge (RR=0.979; 95 %CI=0.979-1.020). On the other hand, Splines plots showed no correlation between GPI and modified Rankin.

CONCLUSIONS

Despite the usefulness of GPI to prognosticate in-hospital complications, its association with functional outcome is inconclusive.

Causal Relationships Between Gut Microbiota, Inflammatory Cells/Proteins, and Subarachnoid Hemorrhage: A Multi-omics Bidirectional Mendelian Randomization Study and Meta-analysis

Subarachnoid hemorrhage (SAH) is a neurological emergency that can lead to fatal outcomes. It occurs when bleeding happens in the subarachnoid space, a small gap between the arachnoid and pia mater. This condition results from the rupture of diseased or damaged blood vessels at the brain's base or surface. This study combined various omics approaches with Mendelian randomization analysis, including MR-IVW, MR Egger, MR weight median, and MR weight mode, to generate preliminary results. It also employed reverse Mendelian randomization, treating SAH as the exposure. Finally, a meta-analysis was conducted to summarize these findings. The study found positive correlations between SAH and both GBPA-Pyridoxal 5 phosphate biosynthesis I (OR=1.48, 95% CI, 1.04-2.12) and GBPA-glucose biosynthesis I (OR=0.68, 95% CI, 0.52-0.90). Increased levels of urokinase-type plasma activator were also associated with SAH (OR=1.17, 95% CI, 1.04-1.32). Associations were observed with SAH for CD80 on CD62L+ plasmacytoid dendritic cells, CD80 on plasmacytoid dendritic cells, CD123 on CD62L+ plasmacytoid dendritic cells, and SSC-A on plasmacytoid dendritic cells. This study, through Mendelian randomization and meta-analysis, established links between SAH and four inflammatory cells, one inflammatory protein, and two gut microbiota-related pathways. These findings suggest potential treatment targets for SAH, highlighting the importance of modulating gut microbiota and utilizing anti-inflammatory drugs in its management.

Cerebrospinal fluid markers of neuroinflammation and coagulation in severe cerebral edema and chronic hydrocephalus after subarachnoid hemorrhage: a prospective study

BACKGROUND

Early severe cerebral edema and chronic hydrocephalus are the primary cause of poor prognosis in patients with subarachnoid hemorrhage (SAH). This study investigated the role of cerebrospinal fluid (CSF) inflammatory cytokines and coagulation factors in the development of severe cerebral edema and chronic hydrocephalus in patients with SAH.

METHODS

Patients with SAH enrolled in this study were categorized into mild and severe cerebral edema groups based on the Subarachnoid Hemorrhage Early Brain Edema Score at admission. During long-term follow-up, patients were further classified into hydrocephalus and non-hydrocephalus groups. CSF samples were collected within 48 h post-SAH, and levels of inflammatory cytokines and coagulation factors were measured. Univariate and multivariate logistic regression analyses were performed to identify independent factors associated with severe cerebral edema and chronic hydrocephalus. The correlation between inflammatory cytokines and coagulation factors was further investigated and validated in a mouse model of SAH.

RESULTS

Seventy-two patients were enrolled in the study. Factors from the extrinsic coagulation pathway and inflammatory cytokines were associated with both severe cerebral edema and chronic hydrocephalus. Coagulation products thrombin-antithrombin complexes (TAT) and fibrin, as well as inflammatory cytokines IL-1β, IL-2, IL-5, IL-7, and IL-4, were independently associated with severe cerebral edema. Additionally, Factor VII, fibrin, IL-2, IL-5, IL-12, TNF-α, and CCL-4 were independently associated with chronic hydrocephalus. A positive correlation between extrinsic coagulation factors and inflammatory cytokines was observed. In the SAH mouse model, tissue plasminogen activator was shown to alleviate neuroinflammation and cerebral edema, potentially by restoring glymphatic-meningeal lymphatic function.

CONCLUSIONS

Elevated levels of inflammatory cytokines and extrinsic coagulation pathway factors in the CSF are associated with the development of early severe cerebral edema and chronic hydrocephalus following SAH. These factors are interrelated and may contribute to post-SAH glymphatic-meningeal lymphatic dysfunction.

Inflammasome Proteins Are Reliable Biomarkers of the Inflammatory Response in Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is caused by abnormal blood vessel dilation and subsequent rupture, resulting in blood pooling in the subarachnoid space. This neurological insult results in the activation of the inflammasome, a multiprotein complex that processes pro-inflammatory interleukin (IL)-1 cytokines leading to morbidity and mortality. Moreover, increases in inflammasome proteins are associated with clinical deterioration in many neurological diseases. Limited studies have investigated inflammasome protein expression following aSAH. Reliable markers of the inflammatory response associated with aSAH may allow for earlier detection of patients at risk for complications and aid in the identification of novel pharmacologic targets. Here, we investigated whether inflammasome signaling proteins may serve as potential biomarkers of the inflammatory response in aSAH. Serum and cerebrospinal fluid (CSF) from fifteen aSAH subjects and healthy age-matched controls and hydrocephalus (CSF) no-aneurysm controls were evaluated for levels of inflammasome signaling proteins and downstream pro-inflammatory cytokines. Protein measurements were carried out using Simple Plex and Single-Molecule Array (Simoa) technology. The area under the curve (AUC) was calculated using receiver operating characteristics (ROCs) to obtain information on biomarker reliability, specificity, sensitivity, cut-off points, and likelihood ratio. In addition, a Spearman r correlation matrix was performed to determine the correlation between inflammasome protein levels and clinical outcome measures. aSAH subjects demonstrated elevated caspase-1, apoptosis-associated speck-like protein with a caspase recruiting domain (ASC), IL-18 and IL-1β levels in serum, and CSF when compared to controls. Each of these proteins was found to be a promising biomarker of inflammation in aSAH in the CSF. In addition, ASC, caspase-1, and IL-1β were found to be promising biomarkers of inflammation in aSAH in serum. Furthermore, we found that elevated levels of inflammasome proteins in serum are useful to predict worse functional outcomes following aSAH. Thus, the determination of inflammasome protein levels in CSF and serum in aSAH may be utilized as reliable biomarkers of inflammation in aSAH and used clinically to monitor patient outcomes.

An exploration on the machine-learning-based stroke prediction model

Introduction

With the rapid development of artificial intelligence technology, machine learning algorithms have been widely applied at various stages of stroke diagnosis, treatment, and prognosis, demonstrating significant potential. A correlation between stroke and cytokine levels in the human body has recently been reported. Our study aimed to establish machine-learning models based on cytokine features to enhance the decision-making capabilities of clinical physicians.

Methods

This study recruited 2346 stroke patients and 2128 healthy control subjects from Chongqing University Central Hospital. A predictive model was established through clinical experiments and collection of clinical laboratory tests and demographic variables at admission. Three classification algorithms, namely Random Forest, Gradient Boosting, and Support Vector Machine, were employed. The models were evaluated using methods such as ROC curves, AUC values, and calibration curves.

Results

Through univariate feature selection, we selected 14 features and constructed three machine-learning models: Support Vector Machine (SVM), Random Forest (RF), and Gradient Boosting Machine (GBM). Our results indicated that in the training set, the RF model outperformed the GBM and SVM models in terms of both the AUC value and sensitivity. We ranked the features using the RF algorithm, and the results showed that IL-6, IL-5, IL-10, and IL-2 had high importance scores and ranked at the top. In the test set, the stroke model demonstrated a good generalization ability, as evidenced by the ROC curve, confusion matrix, and calibration curve, confirming its reliability as a predictive model for stroke.

Discussion

We focused on utilizing cytokines as features to establish stroke prediction models. Analyses of the ROC curve, confusion matrix, and calibration curve of the test set demonstrated that our models exhibited a strong generalization ability, which could be applied in stroke prediction.

HDL anti-inflammatory function is impaired and associated with high SAA1 and low APOA4 levels in aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating disease with high morbidity and mortality rates. Within 24 hours after aSAH, monocytes are recruited and enter the subarachnoid space, where they mature into macrophages, increasing the inflammatory response and contributing, along with other factors, to delayed neurological dysfunction and poor outcomes. High-density lipoproteins (HDL) are lipid-protein complexes that exert anti-inflammatory effects but under pathological conditions undergo structural alterations that have been associated with loss of functionality. Plasma HDL were isolated from patients with aSAH and analyzed for their anti-inflammatory activity and protein composition. HDL isolated from patients lost the ability to prevent VCAM-1 expression in endothelial cells (HUVEC) and subsequent adhesion of THP-1 monocytes to the endothelium. Proteomic analysis showed that HDL particles from patients had an altered composition compared to those of healthy subjects. We confirmed by western blot that low levels of apolipoprotein A4 (APOA4) and high of serum amyloid A1 (SAA1) in HDL were associated with the lack of anti-inflammatory function observed in aSAH. Our results indicate that the study of HDL in the pathophysiology of aSAH is needed, and functional HDL supplementation could be considered a novel therapeutic approach to the treatment of the inflammatory response after aSAH.

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.

Cortical Spreading Depolarization and Delayed Cerebral Ischemia; Rethinking Secondary Neurological Injury in Subarachnoid Hemorrhage

Poor outcomes in Subarachnoid Hemorrhage (SAH) are in part due to a unique form of secondary neurological injury known as Delayed Cerebral Ischemia (DCI). DCI is characterized by new neurological insults that continue to occur beyond 72 h after the onset of the hemorrhage. Historically, it was thought to be a consequence of hypoperfusion in the setting of vasospasm. However, DCI was found to occur even in the absence of radiographic evidence of vasospasm. More recent evidence indicates that catastrophic ionic disruptions known as Cortical Spreading Depolarizations (CSD) may be the culprits of DCI. CSDs occur in otherwise healthy brain tissue even without demonstrable vasospasm. Furthermore, CSDs often trigger a complex interplay of neuroinflammation, microthrombi formation, and vasoconstriction. CSDs may therefore represent measurable and modifiable prognostic factors in the prevention and treatment of DCI. Although Ketamine and Nimodipine have shown promise in the treatment and prevention of CSDs in SAH, further research is needed to determine the therapeutic potential of these as well as other agents.

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.

Diagnosis potential of subarachnoid hemorrhage using miRNA signatures isolated from plasma-derived extracellular vesicles

The diagnosis and clinical management of aneurysmal subarachnoid hemorrhage (aSAH) is currently limited by the lack of accessible molecular biomarkers that reflect the pathophysiology of disease. We used microRNAs (miRNAs) as diagnostics to characterize plasma extracellular vesicles in aSAH. It is unclear whether they can diagnose and manage aSAH. Next-generation sequencing (NGS) was used to detect the miRNA profile of plasma extracellular vesicles (exosomes) in three patients with SAH and three healthy controls (HCs). We identified four differentially expressed miRNAs and validated the results using quantitative real-time polymerase chain reaction (RT-qPCR) with 113 aSAH patients, 40 HCs, 20 SAH model mice, and 20 sham mice. Exosomal miRNA NGS revealed that six circulating exosomal miRNAs were differentially expressed in patients with aSAH versus HCs and that the levels of four miRNAs (miR-369-3p, miR-410-3p, miR-193b-3p, and miR-486-3p) were differentially significant. After multivariate logistic regression analysis, only miR-369-3p, miR-486-3p, and miR-193b-3p enabled prediction of neurological outcomes. In a mouse model of SAH, greater expression of miR-193b-3p and miR-486-3p remained statistically significant relative to controls, whereas expression levels of miR-369-3p and miR-410-3p were lower. miRNA gene target prediction showed six genes associated with all four of these differentially expressed miRNAs. The circulating exosomes miR-369-3p, miR-410-3p, miR-193b-3p, and miR-486-3p may influence intercellular communication and have potential clinical utility as prognostic biomarkers for aSAH patients.