Perivascular Neutrophil Extracellular Traps Exacerbate Microvasospasm After Experimental Subarachnoid Hemorrhage

Area of Science:

• Neuroscience
• Vascular Biology
• Immunology

Background:

• Subarachnoid hemorrhage (SAH) can cause acute or delayed cerebral ischemia.
• Perivascular inflammation and microvasospasms are implicated in SAH-related ischemia.
• Mechanisms underlying microvasospasms remain poorly understood due to investigation challenges.

Purpose of the Study:

• To investigate the vascular and perivascular pathology following SAH.
• To elucidate the role of neutrophils and neutrophil extracellular traps (NETs) in SAH-induced microvasospasm.

Main Methods:

• Established a SAH mouse model combined with intravital 2-photon imaging.
• Analyzed erythrocyte distribution, neutrophil behavior, and pial arteriole morphology.
• Utilized neutrophil depletion and NETs removal to assess their impact on microvasospasm.

Main Results:

• Erythrocytes rapidly occupied the perivascular space post-SAH.
• Neutrophils infiltrated the perivascular space and underwent NETosis.
• Pearl-string-like microvasospasms developed in pial arterioles, significantly reduced by neutrophil depletion and NETs removal.

Conclusions:

• Perivascular neutrophil extracellular traps (NETs) play a critical role in the development of microvasospasms after SAH.
• Targeting perivascular NETs presents a potential therapeutic strategy for SAH-induced microvasospasm.