Elevation of serum CXC chemokine ligand-12 levels predicts poor outcome after aneurysmal subarachnoid hemorrhage

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.

Single-cell sequencing reveals intracranial microvasculature-derived CXCL12 promotes CD8+ T-cell infiltration and blood-brain barrier dysfunction after subarachnoid hemorrhage in mice

BACKGROUND

Processes related to how the intracranial microvasculature initiates brain‒peripheral crosstalk for subsequent blood‒brain barrier (BBB) dysfunction at an early stage after subarachnoid hemorrhage (SAH) ictus are still unknown. This study elucidated the effect and potential mechanism of intracranial microvasculature-mediated T-cell infiltration on BBB function after SAH.

METHODS

Publicly available single-cell RNA sequencing data related to SAH ( https://ngdc.cncb.ac.cn/omix ; Accession No. OMIX006611) were retrieved and analyzed. The dataset was derived from the white matter region of adult male C57BL/6J mice at 1 and 7 days after experimental SAH. The SAH model was induced by endovascular perforation, and experiments were subsequently conducted at 1, 3, 7, and 14 days after SAH to evaluate T-cell infiltration, BBB integrity, neuronal injury, and neurological function.

RESULTS

After SAH, CXCL12 expression was increased in endothelial cells and pericytes, promoting CD8+ T-cell infiltration via the CXCR4 pathway. This immune infiltration appeared to exacerbate BBB disruption and contribute to worsened neurological function. Blocking CXCL12-CXCR4 signaling with a CXCL12 neutralizing antibody or the CXCR4-specific inhibitor AMD3100 significantly reduced CD8+ T-cell infiltration, attenuated BBB damage and improved the neurobehavioral outcomes of SAH mice.

CONCLUSION

This study suggests that, following SAH, both pericytes and endothelial cells may contribute to immune regulation by producing CXCL12, which promotes CD8⁺ T-cell infiltration into the brain. This mechanism may play a role in BBB disruption and neurological dysfunction. Targeting the CXCL12-CXCR4 axis could offer a potential approach for mitigating immune-mediated injury after SAH.

Elevated levels of several chemokines in the cerebrospinal fluid of patients with subarachnoid hemorrhage are associated with worse clinical outcome

BACKGROUND

Chemokines are small cytokines that exert chemotactic actions on immune cells and are involved in many inflammatory processes. The present study aims to provide insight in the role of this relatively unexplored family of proteins in the inflammatory pathophysiology of subarachnoid hemorrhage (SAH).

MATERIALS AND METHODS

Cerebrospinal fluid of 29 patients (17 female; mean age 57 years) was collected at days 1, 4 and 10 after SAH, centrifuged and frozen at -70°C. Analysis of 92 inflammation-related proteins was performed using Target 96 Inflammation ® assay (Olink Proteomics, Uppsala, Sweden) based on Proximity Extension Assay technology. The panel included 20 chemokines (CCL2 (or MCP-1), CCL3, CCL4, CCL7 (or MCP-3), CCL8 (or MCP-2), CCL11 (or Eotaxin), CCL13 (or MCP-4), CCL19, CCL20, CCL23, CCL25, CCL28, CXCL1, CXCL5, CXCL6, CXCL8 (or IL-8), CXCL9, CXCL10, CXCL11 and CX3CL1 (or Fractalkine)) that were analyzed for their temporal patterns of expression and compared in dichotomized clinical groups based on World Federation of Neurosurgical Societies (WFNS) admission score and amount of blood on admission CT based on Fisher scale; presence of delayed cerebral ischemia(DCI)/delayed ischemic neurological deficit (DIND); and clinical outcome based on Glasgow Outcome Scale. Protein expression levels were provided in output unit Normalized Protein Expression (NPX). ANOVA models were used for statistical analyses.

RESULTS

Four temporal patterns of expression were observed (i.e., early, middle, late peak and no peak). Significantly higher day 10 mean NPX values were observed in patients with poor outcome (GOS 1-3) for chemokines CCL2, CCL4, CCL7, CCL11, CCL13, CCL19, CCL20, CXCL1, CXCL5, CXCL6 and CXCL8. In the WFNS 4-5 group, CCL11 showed significantly higher day 4 and day 10 mean NPX values and CCL25 significantly higher day 4 values. In patients with SAH Fisher 4, CCL11 showed significantly higher mean NPX values on days 1, 4 and 10. Finally, patients with DCI/DIND had significantly higher day 4 mean NPX values of CXCL5.

CONCLUSION

Higher levels of multiple chemokines at the late stage of SAH seemed to correlate with worse clinical outcome. A few chemokines correlated with WFNS score, Fisher score and occurrence of DCI/DIND. Chemokines may be useful as biomarkers for describing the pathophysiology and prognosis of SAH. Further studies are needed to better understand their exact mechanism of action in the inflammatory cascade.

Role of platelets in the pathogenesis of delayed injury after subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) patients develop delayed cerebral ischemia and delayed deficits (DCI) within 2 weeks of aneurysm rupture at a rate of approximately 30%. DCI is a major contributor to morbidity and mortality after SAH. The cause of DCI is multi-factorial with contributions from microthrombi, blood vessel constriction, inflammation, and cortical spreading depolarizations. Platelets play central roles in hemostasis, inflammation, and vascular function. Within this review, we examine the potential roles of platelets in microthrombi formation, large artery vasospasm, microvessel constriction, inflammation, and cortical spreading depolarization. Evidence from experimental and clinical studies is provided to support the role(s) of platelets in each pathophysiology which contributes to DCI. The review concludes with a suggestion for future therapeutic targets to prevent DCI after aSAH.

Vitamin D-A New Perspective in Treatment of Cerebral Vasospasm

BACKGROUND

Cerebral vasospasm (CVS) is a frequent complication after subarachnoid hemorrhage (SAH), with no sufficient therapy and a complex pathophysiology.

OBJECTIVE

To explore the vitamin D system as a potential treatment for CVS.

METHODS

25-vitamin D3 levels tested between 2007 and 2015 and data of SAH patients admitted during the months with a peak vs nadir of VitD3 values were analyzed, retrospectively. We prospectively correlated VitD3 and vasospasm/outcome data in SAH patients admitted in 2017. An experimental mice SAH model and cell culture model were used to investigate the effect of 1,25-dihydroxyvitamin D3 (1,25-VitD3). Additionally, the mediators acting in the VitD mechanism were researched and detected.

RESULTS

Based on the retrospective analysis demonstrating an increased frequency of vasospasm in SAH patients during the low vitamin D period in winter, we started basic research experiments. Active 1,25-VitD3 hormone attenuated CVS, neurological deficit, and inflammation after intrathecal blood injection in mice. Deletion of the vitamin D receptor in the endothelium or in myeloid cells decreased the protective 1,25-VitD3 effect. Co-culture experiments of myeloid and endothelial cells with blood confirmed the anti-inflammatory 1,25-VitD3 effect but also revealed an induction of stroma-cell-derived factor 1α (SDF1α), vascular endothelial growth factor, and endothelial nitric oxide synthase by 1,25-VitD3. In mice, SDF1α mimicked the protective effect of 1,25-VitD3 against CVS. From bench to bedside, CVS severity was inversely correlated with vitamin D plasma level, prospectively. Patients with more severe CVS exhibited attenuated expression of SDF1α and 1,25-VitD3-responsive genes on circulating myeloid cells.

CONCLUSION

1,25-VitD3 attenuates CVS after SAH by inducing SDF1α. However, VitD administration should be tested as optional treatment to prevent CVS.

Serum CXC chemokine ligand-12 as a potential predictor for in-hospital major adverse events after severe traumatic brain injury

BACKGROUND

CXC chemokine ligand-12 (CXCL12) is associated with brain inflammation. We attempted to discern whether serum CXCL12 is a promising predictor for in-hospital major adverse events (IMAEs) after traumatic brain injury (TBI), including death, acute lung injury, acute traumatic coagulopathy, progressive hemorrhagic injury and posttraumatic cerebral infarction.

METHODS

In this prospective, observational study, serum CXCL12 levels were quantified among 117 severe TBI patients. We investigated the relation of CXCL12 levels to IMAEs using a multivariate analysis.

RESULTS

Median value of serum CXCL12 concentrations was substantially higher in patients with IMAEs than in other remainders (21.1 vs. 11.6 ng/ml). With an increasing number of IMAEs, serum CXCL12 concentrations were significantly increased (r = 0.702). Serum CXCL12 independently predicted IMAEs (odds ratio, 1.253; 95% CI, 1.100-1.428). Serum CXCL12 concentrations discriminated risk of IMAEs with area under receiver operating characteristic curve of 0.759 (95% CI, 0.672-0.834), its concentrations >16.0 ng/ml distinguished IMAEs with 83.9% sensitivity and 67.2% specificity and its combination with Glasgow coma scale scores produced the best predictive ability compared with each one alone (p = 0.0116 or 0.0004).

CONCLUSION

Serum CXCL12 concentrations are independently associated with IMAEs following TBI, substantializing serum CXCL12 as a useful prognostic biomarker for head trauma patients.

White matter repair and treatment strategy after intracerebral hemorrhage

The predilection site of intracerebral hemorrhage (ICH) is in the basal ganglia, which is rich in white matter (WM) fiber bundles, such as cerebrospinal tract in the internal capsule. ICH induced damage to this area can easily lead to severe neurological dysfunction and affects the prognosis and quality of life of patients. At present, the pathophysiological mechanisms of white matter injury (WMI) after ICH have attracted researchers' attention, but studies on the repair and recovery mechanisms and therapy strategies remain rare. In this review, we mainly summarized the WM recovery and treatment strategies after ICH by updating the WMI-related content by reviewing the latest researches and proposing the bottleneck of the current research.

Detection of high serum concentration of CXC chemokine ligand-12 in acute intracerebral hemorrhage

BACKGROUND

CXC chemokine ligand-12 (CXCL12), a member of the CXC chemokine subfamily, is involved in both focal angiogenesis and inflammatory reactions. We examined serum CXCL12 concentration in intracerebral hemorrhage (ICH) patients and its correlation to stroke severity and outcome.

METHODS

The study was carried out on 105 ICH patients on 105 healthy controls. Serum samples were at admission obtained to measure CXCL12 concentrations. The National Institutes of Health Stroke Scale (NIHSS) and hematoma volume were recorded to assess stroke severity.

RESULTS

As compared to the controls, CXCL12 concentrations were significantly increased in the patients. Also, non-survivors within 6months and patients with an unfavorable outcome (modified Rankin Scale score>2) at 6months had higher CXCL12 concentrations than other remaining ones. CXCL12 concentrations had positive correlation with NIHSS scores and hematoma volume. Serum CXCL12 significantly discriminated patients at risk of 6-month mortality and 6-month unfavorable outcome under receiver operating characteristic curve. Moreover, serum CXCL12 was independently associated with the mortality, overall survival and unfavorable outcome.

CONCLUSIONS

Serum CXCL12 concentrations are enhanced after ICH and CXCL12 in serum has the potential to reflect severity and prognosis following hemorrhagic stroke.

Prognostic value of plasma galectin-3 levels after aneurysmal subarachnoid hemorrhage

BACKGROUND

Inflammatory responses are correlated with secondary brain injury after aneurysmal subarachnoid hemorrhage (aSAH). Galectin-3 (Gal-3) is a novel biomarker reflecting inflammation status, and its elevated circulating levels are associated with poor prognosis of some inflammatory diseases. The aim of this study was to evaluate the relationship between Gal-3 plasma levels and prognosis in a group of aSAH patients.

MATERIALS AND METHODS

We assessed plasma Gal-3 levels in 120 patients and 120 healthy individuals. 6-month clinical outcomes included mortality and unfavorable outcome (Glasgow Outcome Scale score of 1-3). Associations of plasma Gal-3 levels with clinical outcomes were investigated using multivariate analysis.

RESULTS

Patients showed significantly higher Gal-3 levels as compared to controls. Circulating Gal-3 was significantly and independently associated with 6-month clinical outcomes in the logistic regression analysis. Moreover, we observed a significant correlation between circulating Gal-3 and World Federation of Neurological Surgeons scores and modified Fisher scores. Furthermore, Gal-3 possessed high area under receiver operating characteristic curve for prognostic assessment.

CONCLUSION

Our findings indicate the associations between Gal-3 levels and the severity and poor prognosis following aSAH. This suggests the possible role of Gal-3 in the prognostic prediction after aSAH.