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-6(sEVs) levels using an enzyme-linked immunosorbent assay. Results were statistically analyzed to determine the function of IL-6(sEVs) for disease monitoring of aSAH. RESULTS: CSF IL-6 (sEVs) showed distinct pattern differences between healthy controls and aSAH patients. The concentration of IL-6(sEVs) in CSF is significantly correlated with the severity of aSAH patients. The areas under the receiver operating characteristic curves of IL-6(sEVs) for identifying severe aSAH patient from aSAH patients were 0.900. After multivariate logistic regression analysis, IL-6(sEVs) were associated with neurological outcome at 1 year. IL-6(sEVs) levels were greater and positively associated with disease processes and outcome. CONCLUSION: There is a neuroinflammatory cascade in aSAH patients. IL-6(sEVs) in CSF may be a biomarker for the progression of aSAH.