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Published on: June 4, 2021
EXPRESS: The Role of Complement System in Hemorrhagic Stroke
Yingfeng Wan1, Preethi Reddi1, Adam Fox1
1Departments of Neurosurgery, University of Michigan, Ann Arbor, MI, USA.
Summary
The complement system drives secondary brain injury after hemorrhagic stroke. Targeting this system shows therapeutic promise but requires understanding its complex roles in subarachnoid hemorrhage, intracerebral hemorrhage, and intraventricular hemorrhage.
Area of Science:
- Neuroscience
- Immunology
- Biochemistry
Background:
- Hemorrhagic stroke, including SAH, ICH, and IVH, causes significant morbidity and mortality.
- Secondary injury mechanisms like neuroinflammation and oxidative stress are key drivers.
- The complement system is increasingly recognized as a central mediator in these processes.
Purpose of the Study:
- To review the role of the complement system in secondary injury following different types of hemorrhagic stroke.
- To discuss the implications of complement activation in SAH, ICH, and IVH.
- To explore the potential of complement-targeted therapies.
Main Methods:
- Literature review of studies investigating complement activation in hemorrhagic stroke models and patients.
- Analysis of complement pathway involvement (classical, lectin, alternative) and key mediators (C3, MAC).
- Examination of complement-coagulation crosstalk and therapeutic strategies.
Main Results:
- Complement activation is rapid and crucial in SAH, contributing to early brain injury and delayed ischemia.
- Complement plays dual roles in ICH, mediating inflammation and edema while aiding hematoma clearance.
- In IVH, complement is implicated in hydrocephalus, white matter injury, and long-term deficits.
Conclusions:
- The complement system is a critical mediator of secondary injury across various hemorrhagic stroke types.
- Complement-targeted therapies demonstrate potential but face challenges due to context-dependent signaling.
- Future research should prioritize biomarkers and precision medicine approaches for complement inhibition.
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