Complement proteins changes in ischemic stroke patients and their relation to outcome

Area of Science:

• Neuroscience
• Immunology
• Biochemistry

Background:

• The complement system is crucial in innate immunity and inflammation.
• Its role in ischemic stroke pathogenesis is complex and not fully understood.
• Dynamic changes in complement factors may influence stroke outcomes.

Purpose of the Study:

• To investigate the dynamic changes in plasma complement factor levels during the acute phase of ischemic stroke.
• To correlate these changes with stroke severity and patient outcomes.

Main Methods:

• Plasma samples were collected from 84 ischemic stroke patients within 24 hours of symptom onset and on day 7.
• Luminex immunoassay was used to quantify levels of complement factors C1q, C2, C3, C3b, C4, C4b, C5, C5a, and C9.
• National Institutes of Health Stroke Scale (NIHSS) was used to assess stroke severity.

Main Results:

• Most complement factors (C1q, C2, C3, C3b, C4, C4b, C5, C5a) showed significantly lower levels on day 7 compared to day 1.
• Patients with poor outcomes (NIHSS ≥16 or death) exhibited higher C9 levels at both time points.
• Higher C2, C5, and C5a levels were observed on day 7 in patients with poor outcomes.
• Complement factors C2, C5, C5a, and C9 correlated with the final NIHSS score.

Conclusions:

• Plasma complement factor levels undergo dynamic changes in the early hours and days following an ischemic stroke.
• Elevated baseline C9 levels are associated with worse outcomes in the acute phase of ischemic stroke.
• These findings suggest C9 may serve as a potential biomarker for predicting stroke severity and prognosis.