Elevated Systemic IL-10 Levels Indicate Immunodepression Leading to Nosocomial Infections after Aneurysmal Subarachnoid Hemorrhage (SAH) in Patients

Non-invasive Auricular Vagus nerve stimulation for Subarachnoid Hemorrhage (NAVSaH): Protocol for a prospective, triple-blinded, randomized controlled trial

Background

Inflammation has been implicated in driving the morbidity associated with subarachnoid hemorrhage (SAH). Despite understanding the important role of inflammation in morbidity following SAH, there is no current effective way to modulate this deleterious response. There is a critical need for a novel approach to immunomodulation that can be safely, rapidly, and effectively deployed in SAH patients. Vagus nerve stimulation (VNS) provides a non-pharmacologic approach to immunomodulation, with prior studies demonstrating VNS can reduce systemic inflammatory markers, and VNS has had early success treating inflammatory conditions such as arthritis, sepsis, and inflammatory bowel diseases. The aim of the Non-invasive Auricular Vagus nerve stimulation for Subarachnoid Hemorrhage (NAVSaH) trial is to translate the use of non-invasive transcutaneous auricular VNS (taVNS) to spontaneous SAH, with our central hypothesis being that implementing taVNS in the acute period following spontaneous SAH attenuates the expected inflammatory response to hemorrhage and curtails morbidity associated with inflammatory-mediated clinical endpoints.

Materials and methods

The overall objectives for the NAHSaH trial are to 1) Define the impact that taVNS has on SAH-induced inflammatory markers in the plasma and cerebrospinal fluid (CSF), 2) Determine whether taVNS following SAH reduces radiographic vasospasm, and 3) Determine whether taVNS following SAH reduces chronic hydrocephalus. Following presentation to a single enrollment site, enrolled SAH patients are randomly assigned twice daily treatment with either taVNS or sham stimulation for the duration of their intensive care unit stay. Blood and CSF are drawn before initiation of treatment sessions, and then every three days during a patient's hospital stay. Primary endpoints include change in the inflammatory cytokine TNF-α in plasma and cerebrospinal fluid between day 1 and day 13, rate of radiographic vasospasm, and rate of requirement for long-term CSF diversion via a ventricular shunt. Secondary outcomes include exploratory analyses of a panel of additional cytokines, number and type of hospitalized acquired infections, duration of external ventricular drain in days, interventions required for vasospasm, continuous physiology data before, during, and after treatment sessions, hospital length of stay, intensive care unit length of stay, and modified Rankin Scale score (mRS) at admission, discharge, and each at follow-up appointment for up to two years following SAH.

Discussion

Inflammation plays a central role in morbidity following SAH. This NAVSaH trial is innovative because it diverges from the pharmacologic status quo by harnessing a novel non-invasive neuromodulatory approach and its known anti-inflammatory effects to alter the pathophysiology of SAH. The investigation of a new, effective, and rapidly deployable intervention in SAH offers a new route to improve outcomes following SAH.

Trial registration

Clinical Trials Registered, NCT04557618. Registered on September 21, 2020, and the first patient was enrolled on January 4, 2021.

Perioperative Infection After Aneurysmal Subarachnoid Hemorrhage: Risk Factors, Causative Pathogens, and Long-Term Outcomes

BACKGROUND AND OBJECTIVES

Nosocomial infections are the most common complication among critically ill patients and contribute to poor long-term outcomes. Patients with aneurysmal subarachnoid hemorrhage (aSAH) are highly susceptible to perioperative infections, yet it is unclear what factors influence infection onset and functional recovery. The objective was to investigate risk factors for perioperative infections after aSAH and relate causative pathogens to patient outcomes.

METHODS

Clinical records were obtained for 194 adult patients with aSAH treated at our institution from 2016 to 2020. Demographics, clinical course, complications, microbiological reports, and outcomes were collected. χ 2 , univariate, and multivariate logistic regression analyses were used to analyze risk factors.

RESULTS

Nearly half of the patients developed nosocomial infections, most frequently pneumonia and urinary tract infection. Patients with infections had longer hospital stays, higher rates of delayed cerebral ischemia, and worse functional recovery up to 6 months after initial hemorrhage. Independent risk factors for pneumonia included male sex, comatose status at admission, mechanical ventilatory use, and longer admission, while those for urinary tract infection included older age and longer admission. Staphylococcus , Klebsiella , and Enterococcus spp. were associated with poor long-term outcome. Certain pathogenic organisms were associated with delayed cerebral ischemia.

CONCLUSION

Perioperative infections are highly prevalent among patients with aSAH and are related to adverse outcomes. The risk profiles for nosocomial infections are distinct to each infection type and causative organism. Although strong infection control measures should be universally applied, patient management must be individualized in the context of specific infections.

Lower Serum Iron Level Predicts Postoperative Global Cerebral Edema Following Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Iron plays an important role in neuronal injury and edema formation after intracranial hemorrhage. However, the role of serum iron in aneurysmal subarachnoid hemorrhage (aSAH) is yet to be well-established. This study aims to identify whether serum iron could predict postoperative global cerebral edema (GCE) and poor outcome in aSAH.

METHODS

847 patients' aSAH clinical data were retrospectively collected at the First Affiliated Hospital of Fujian Medical University. Data on demographics, clinical characteristics, and laboratory values were collected and analyzed through univariate and multivariate analyses. Propensity score matching (PSM) analysis was performed to balance the baseline differences between the groups.

RESULTS

The incidence of high-grade global cerebral edema (H-GCE) following aSAH was 12.99% (110/847). Serum iron levels [odds ratio (OR) = 1.143; 95% confidence interval (CI), (1.097-1.191); p < 0.001] were associated with the occurrence of H-GCE following aSAH in the univariate analysis. This association remained statistically significant even after adjusting for other variables in the multivariate model, with serum iron having an OR of 1.091 (95% CI, 1.043-1.141; p < 0.001) for GCE. After 1:1 PSM, serum iron levels ≤ 10.7 µmol/L remained a significant independent predictor of GCE (p = 0.002). The receiver operating characteristic (ROC) curve analysis determined that a serum iron cut-off value of ≤ 10.7 µmol/L was optimal for predicting H-GCE [Areas under the ROC curves (AUC) = 0.701, 95% CI, (0.669-0.732), p < 0.001; sensitivity, 67.27%; specificity, 63.77%] in patients with aSAH. Additionally, a trend was observed in which higher Hunt-Hess grades (HH grade) were associated with lower serum iron levels, and higher modified Fisher grades (mFisher grade) were associated with lower serum iron levels. In addition, the serum iron level was also associated with a 3-month functional neurological outcome (p < 0.001).

CONCLUSIONS

The results of this study indicate that a decreased serum iron level serves as a clinically significant biomarker for the prediction of postoperative GCE and a poor outcome at 3-months in patients with aSAH.

Diagnosis of post-neurosurgical bacterial meningitis in patients with aneurysmal subarachnoid hemorrhage based on the immunity-related proteomics signature of the cerebrospinal fluid

Introduction

Post-neurosurgical bacterial meningitis (PNBM) is a serious complication for patients who receive neurosurgical treatment, but the diagnosis is difficult given the complicated microenvironment orchestrated by sterile brain injury and pathogenic infection. In this study, we explored potential diagnostic biomarkers and immunological features using a proteomics platform.

Methods

A total of 31 patients with aneurysmal subarachnoid hemorrhage (aSAH) who received neurosurgical treatment were recruited for this study. Among them, 15 were diagnosed with PNBM. The remaining 16 patients were categorized into the non-PNBM group. Proteomics analysis of the cerebrospinal fluid (CSF) was conducted on the Olink platform, which contained 92 immunity-related molecules.

Results

We found that the expressions of 27 CSF proteins were significantly different between the PNBM and non-PNBM groups. Of those 27 proteins, 15 proteins were upregulated and 12 were downregulated in the CSF of the PNBM group. The receiver operating characteristic curve analysis indicated that three proteins (pleiotrophin, CD27, and angiopoietin 1) had high diagnostic accuracy for PNBM. Furthermore, we also performed bioinformatics analysis to explore potential pathways and the subcellular localization of the proteins.

Conclusion

In summary, we found a cohort of immunity-related molecules that can serve as potential diagnostic biomarkers for PNBM in patients with aSAH. These molecules also provide an immunological profile of PNBM.

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.

A predictive model using risk factor categories for hospital-acquired pneumonia in patients with aneurysmal subarachnoid hemorrhage

Objectives

To identify risk factors for hospital-acquired pneumonia (HAP) in patients with aneurysmal subarachnoid hemorrhage (aSAH) and establish a predictive model to aid evaluation.

Methods

The cohorts of 253 aSAH patients were divided into the HAP group (n = 64) and the non-HAP group (n = 189). Univariate and multivariate logistic regression were performed to identify risk factors. A logistic model (Model-Logit) was established based on the independent risk factors. We used risk factor categories to develop a model (Model-Cat). Receiver operating characteristic curves were generated to determine the cutoff values. Areas under the curves (AUCs) were calculated to assess the accuracy of models and single factors. The Delong test was performed to compare the AUCs.

Results

The multivariate logistic analysis showed that the age [p = 0.012, odds ratio (OR) = 1.059, confidence interval (CI) = 1.013-1.107], blood glucose (BG; >7.22 mmol/L; p = 0.011, OR = 2.781, CI = 1.263-6.119), red blood distribution width standard deviation (RDW-SD; p = 0.024, OR = 1.118, CI = 1.015-1.231), and Glasgow coma scale (GCS; p < 0.001, OR = 0.710, CI = 0.633-0.798) were independent risk factors. The Model-Logit was as follows: Logit(P) = -5.467 + 0.057 * Age + 1.023 * BG (>7.22 mmol/L, yes = 1, no = 0) + 0.111 * RDW-SD-0.342 * GCS. The AUCs values of the Model-Logit, GCS, age, BG (>7.22 mmol/L), and RDW-SD were 0.865, 0.819, 0.634, 0.698, and 0.625, respectively. For clinical use, the Model-Cat was established. In the Model-Cat, the AUCs for GCS, age, BG, and RDW-SD were 0.850, 0.760, 0.700, 0.641, and 0.564, respectively. The AUCs of the Model-Logit were insignificantly higher than the Model-Cat (Delong test, p = 0.157). The total points from -3 to 4 and 5 to 14 were classified as low- and high-risk levels, respectively.

Conclusions

Age, BG (> 7.22 mmol/L), GCS, and RDW-SD were independent risk factors for HAP in aSAH patients. The Model-Cat was convenient for practical evaluation. The aSAH patients with total points from 5 to 14 had a high risk for HAP, suggesting the need for more attention during treatment.

Pneumonia in Nervous System Injuries: An Analytic Review of Literature and Recommendations

Pneumonia is one of the most common complications in intensive care units and is the most common nosocomial infection in this setting. Patients with neurocritical conditions who are admitted to ICUs are no exception, and in fact, are more prone to infections such as pneumonia because of factors such as swallow dysfunction, need for mechanical ventilation, longer length of stay in hospitals, etc. Common central nervous system pathologies such as ischemic stroke, traumatic brain injury, subarachnoid hemorrhage, intracerebral hemorrhage, neuromuscular disorders, status epilepticus, and demyelinating diseases can cause long in-hospital admissions and increase the risk of pneumonia each with a mechanism of its own. Brain injury-induced immunosuppression syndrome is usually considered the common mechanism through which patients with critical central nervous system conditions become susceptible to different kinds of infection including pneumonia. Evaluating the patients and assessment of the risk factors can lead our attention toward better infection control in this population and therefore decrease the risk of infections in central nervous system injuries.

Clinical Value of Inflammatory Cytokines in Patients with Aneurysmal Subarachnoid Hemorrhage

Background

Inflammation is closely associated with prognosis in patients with aneurysmal subarachnoid hemorrhage (aSAH), which is orchestrated by inflammatory cytokines. Therefore, this study aimed to investigate the levels of inflammatory cytokines in the early stage of aSAH and their predictive value for prognosis.

Methods

In this retrospective study, 206 patients with aSAH were recruited and assigned to a severe group (WFNS grade ≥ 4) and a mild group (WFNS grade < 4) according to the severity of patients on admission. Flow cytometry was performed to detect the levels of 12 inflammatory cytokines in the serum of patients. Then, patients were grouped into a poor prognosis group (mRS score ≥ 4) and a good prognosis group (mRS score < 4) based on their prognosis after 3 months of discharge to compare the relationship between cytokines and prognosis. Propensity score matching (PSM) was utilized to control confounding factors. The correlation between inflammatory factors and prognosis was determined using Spearman correlation, and the predictive efficacy of inflammatory factors was tested by a receiver operating characteristic curve.

Results

Serum IL-1β, IL-5, IL-6, IL-8, IL-10, IFN-γ, and TNF-α levels were significantly higher in the mild group than in the severe group and in the poor prognosis group than in the good prognosis group. After PSM, the differences in IL-1β, IL-5, IFN-α, and IFN-γ levels disappeared between the two groups, whereas IL-2, IL-6, IL-8, IL-10, and TNF-α levels remained higher in the poor prognosis group than in the good prognosis group. Additionally, IL-2, IL-6, IL-8, and IL-10 levels were positively correlated with mRS scores. Moreover, the predictive value was found to be the highest for IL-6 and the lowest for TNF-α.

Conclusion

Inflammation degree was related to the severity of aSAH. Inflammatory markers, including IL-6, IL-10, IL-8, IL-2, and TNF-α, might predict the poor prognosis of aSAH.

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.

Admission Lower Serum Phosphate Ion Levels Predict Acute Hydrocephalus of Aneurysmal Subarachnoid Hemorrhage

Introduction: The relationship between serum phosphate ion (sPi) and the occurrence of acute hydrocephalus (aHCP) in aneurysmal subarachnoid hemorrhage (aSAH) remains largely unknown and controversial. The primary aim of this study was to investigate the association between sPi on admission and aHCP following aSAH.

Methods: The study included 635 patients over the age of 19 years diagnosed with aSAH in our institution from September 2012 to June 2018. Data on clinical characteristics, laboratory parameters, treatments, and outcomes were collected and analyzed. The association between lower sPi levels and aHCP was assessed in univariate and multivariate analyses. Propensity-score matching (PSM) analysis was performed to reduce significant differences in baseline characteristics between the aHCP group and non-HCP group.

Results: The overall incidence of aHCP following aSAH was 19.37% (123/512). Lower sPi levels were detected in patients with aHCP compared with those without [0.86 (0.67–1.06) vs. 1.04 (0.84–1.21) mmol/L] in the univariate analysis. In the multivariate analysis, lower sPi level, high modified Fisher (mFisher) grade, and high Hunt-Hess grade were associated with aHCP [odds ratios (OR) 1.729, 95% confidence interval (CI) 1.139–2.623, p = 0.01; mFisher OR 0.097,95% CI 0.055–0.172, p < 0.001; Hunt-Hess, OR 0.555, 95% CI 0.320–0.961, P = 0.036]. After PSM, the matched aHCP group had a significantly lower sPi level than the matched non-aHCP group [0.86 (0.67–1.06) vs. 0.94 (0.76–1.12) mmol/L, p = 0.044]. The area under the curve (AUC) of the sPi level and the logistic regression model based on these predictors (sPi, Hunt-Hess grade, and mFisher grade) was 0.667 and 0.840 (sensitivity of 88.6% and specificity of 68.4%) for predicting aHCP, respectively.

Conclusions: Lower sPi levels predict the occurrence of aHCP, and the model constructed by sPi levels, Hunt-Hess grade, and mFisher grade markedly enhances the prediction of aHCP after aSAH.

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.

Neuroprotective Strategies in Aneurysmal Subarachnoid Hemorrhage (aSAH)

Aneurysmal subarachnoid hemorrhage (aSAH) remains a disease with high mortality and morbidity. Since treating vasospasm has not inevitably led to an improvement in outcome, the actual emphasis is on finding neuroprotective therapies in the early phase following aSAH to prevent secondary brain injury in the later phase of disease. Within the early phase, neuroinflammation, thromboinflammation, disturbances in brain metabolism and early neuroprotective therapies directed against delayed cerebral ischemia (DCI) came into focus. Herein, the role of neuroinflammation, thromboinflammation and metabolism in aSAH is depicted. Potential neuroprotective strategies regarding neuroinflammation target microglia activation, metalloproteases, autophagy and the pathway via Toll-like receptor 4 (TLR4), high mobility group box 1 (HMGB1), NF-κB and finally the release of cytokines like TNFα or IL-1. Following the link to thromboinflammation, potential neuroprotective therapies try to target microthrombus formation, platelets and platelet receptors as well as clot clearance and immune cell infiltration. Potential neuroprotective strategies regarding metabolism try to re-balance the mismatch of energy need and supply following aSAH, for example, in restoring fuel to the TCA cycle or bypassing distinct energy pathways. Overall, this review addresses current neuroprotective strategies in aSAH, hopefully leading to future translational therapy options to prevent secondary brain injury.

TH17/Treg imbalance and IL-17A increase after severe aneurysmal subarachnoid hemorrhage

To evaluate cerebrospinal fluid (CSF) and peripheral blood (PB) Treg, TH17 cells, TH1, TH2 and related cytokines in the acute phase of aSAH we assessed TH17, TH1, TH2, T regulatory cells and neutrophils in 39 aneurysmal subarachnoid hemorrhage (aSAH) patients and 56 controls. PB TH17 cells and TH17/Treg ratio were higher in CSF and PB of aSAH patients. Serum and CSF IL-17A levels were increased in aSAH. Serum IL-17A levels were associated with vasospasm and ICU mortality. Study results support the role of TH17/IL17 axis in aSAH pathogenesis, turning it into a potential clinical biomarker and a novel target for research.

Targeting High Mobility Group Box 1 in Subarachnoid Hemorrhage: A Systematic Review

Aneurysmal subarachnoid hemorrhage (aSAH) is a complex and potentially deadly disease. Neurosurgical clipping or endovascular coiling can successfully obliterate ruptured aneurysms in almost every case. However, despite successful interventions, the clinical outcomes of aSAH patients are often poor. The reasons for poor outcomes are numerous, including cerebral vasospasm (CVS), post-hemorrhagic hydrocephalus, systemic infections and delayed cerebral ischemia. Although CVS with subsequent cerebral ischemia is one of the main contributors to brain damage after aSAH, little is known about the underlying molecular mechanisms of brain damage. This review emphasizes the importance of pharmacological interventions targeting high mobility group box 1 (HMGB1)-mediated brain damage after subarachnoid hemorrhage (SAH) and CVS. We searched Pubmed, Ovid medline and Scopus for "subarachnoid hemorrhage" in combination with "HMGB1". Based on these criteria, a total of 31 articles were retrieved. After excluding duplicates and selecting the relevant references from the retrieved articles, eight publications were selected for the review of the pharmacological interventions targeting HMGB1 in SAH. Damaged central nervous system cells release damage-associated molecular pattern molecules (DAMPs) that are important for initiating, driving and sustaining the inflammatory response following an aSAH. The discussed evidence suggested that HMGB1, an important DAMP, contributes to brain damage during early brain injury and also to the development of CVS during the late phase. Different pharmacological interventions employing natural compounds with HMGB1-antagonizing activity, antibody targeting of HMGB1 or scavenging HMGB1 by soluble receptors for advanced glycation end products (sRAGE), have been shown to dampen the inflammation mediated brain damage and protect against CVS. The experimental data suggest that HMGB1 inhibition is a promising strategy to reduce aSAH-related brain damage and CVS. Clinical studies are needed to validate these findings that may lead to the development of potential treatment options that are much needed in aSAH.