Inhibition of caspase-1-mediated inflammasome activation reduced blood coagulation in cerebrospinal fluid after subarachnoid haemorrhage

BACKGROUND: Neuroinflammation and blood coagulation responses in cerebrospinal fluid (CSF) contribute to the poor outcome associated with subarachnoid haemorrhage (SAH). We explored the role of caspase-1-mediated inflammasome activation on extrinsic blood coagulation in CSF after SAH. METHODS: Post-SAH proteomic changes and correlation between caspase-1 with extrinsic coagulation factors in human CSF after SAH were analysed. Time course and cell localisation of brain inflammasome and extrinsic coagulation proteins after SAH were explored in a rat SAH model. Pharmacological inhibition of caspase-1 via VX-765 was used to explore the role of caspase-1 in blood clearance and CSF circulation after SAH in rats. Primary astrocytes were used to evaluate the role of caspase-1 in haemoglobin-induced pyroptosis and tissue factor (TF) production/release. FINDINGS: Neuroinflammation and blood coagulation activated after SAH in human CSF. The caspase-1 levels significantly correlated with the extrinsic coagulation factors. The activated caspase-1 and extrinsic coagulation initiator TF was increased on astrocytes after SAH in rats. VX-765 attenuated neurological deficits by accelerating CSF circulation and blood clearance through inhibiting pyroptotic neuroinflammation and TF-induced fibrin deposition in the short-term, and improved learning and memory capacity by preventing hippocampal neuronal loss and hydrocephalus in the long-term after SAH in rats. VX-765 reduced haemoglobin-induced pyroptosis and TF production/release in primary astrocytes. INTERPRETATION: Inhibition of caspase-1 by VX-765 appears to be a potential treatment against neuroinflammation and blood coagulation in CSF after SAH. FUNDING: This study was supported by National Institutes of Health of United States of America, and National Natural Science Foundation of China.