Related Experiment Video
Updated: Jun 10, 2026

Pre-Chiasmatic, Single Injection of Autologous Blood to Induce Experimental Subarachnoid Hemorrhage in a Rat Model
Published on: June 18, 2021
Relevance of cerebral interleukin-6 after aneurysmal subarachnoid hemorrhage
Asita Sarrafzadeh1, Florian Schlenk, Christine Gericke
1Department of Neurosurgery, Campus Virchow Medical Center, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany. asita.sarrafzadeh@charite.de
Background:
This study examines the inflammatory response via interleukin-6 (IL-6) in aneurysmal subarachnoid hemorrhage (aSAH) patients and its association with their clinical course (occurrence of acute focal neurological deficits, AFND; and delayed cerebral ischemia, DCI).
Methods:
A total of 38 consecutive aSAH patients were studied prospectively within 14 days after admission and classified as asymptomatic (n = 9; WFNS grade 1 (1-2), median and quartiles) and symptomatic (n = 29; WFNS grade 4 (2-5)); the latter presenting with AFND (n = 13), DCI (n = 10) or both (n = 6). Levels of pro-inflammatory cytokine IL-6 were determined in cerebral extracellular fluid (ECF, using cerebral microdialysis), cerebrospinal fluid (CSF) and plasma for 10 days after aSAH. Additionally, C-reactive protein (CRP) levels were measured in plasma.
Results:
High IL-6 levels in CSF, ECF and plasma were found in all patients, reflecting a pronounced local inflammatory response after aSAH, followed only in symptomatic patients by a delayed systemic inflammation (CRP P < 0.025, days 7-9 after aSAH). In all compartments, IL-6 levels appeared to be higher in symptomatic patients, accompanied also by a higher ECF lactate-pyruvate ratio (P = 0.04). Cerebral, but not plasma IL-6, levels were indicative of the development of DCI in symptomatic patients (ECF P = 0.003; CSF P = 0.001).
Conclusions:
A pronounced initial cerebral inflammatory state was observed in patients of all WFNS grades, suggesting that IL-6 elevations are not necessarily detrimental. Cerebral, but not plasma IL-6, levels were predictive of the development of delayed ischemic deficits in symptomatic patients, suggesting that CSF or ECF are the best sampling media for future studies.
Related Concept Videos
Cerebral Edema ll: Pathophysiology
Hemorrhagic Stroke ll: Pathophysiology
Cerebral Edema l: Introduction
Bacterial Meningitis II: Pathophysiology
Hemorrhagic Stroke l: Introduction
Ischemic Stroke ll: Pathophysiology
