Intracranial pressure is elevated at 24 h post-stroke in mice

Area of Science:

• Neurology
• Pathophysiology
• Stroke Research

Background:

• Intracranial pressure (ICP) elevation post-stroke is typically attributed to large infarcts and edema.
• Previous research in rats indicated ICP rise occurs early, even with minimal edema.
• This study investigated if a similar phenomenon occurs in mice with small infarcts.

Purpose of the Study:

• To determine if intracranial pressure (ICP) increases 24 hours after a small ischemic stroke in mice.
• To investigate the relationship between infarct/edema volume and ICP elevation in a mouse stroke model.
• To explore potential novel mechanisms of ICP elevation independent of edema.

Main Methods:

• Photothrombotic stroke or sham surgery was induced in mice (n=15).
• Epidural ICP was continuously recorded using a fiber optic catheter at 1 hour (baseline) and 23-24 hours post-stroke.
• Statistical analysis was performed to compare ICP levels between stroke and sham groups and across time points.

Main Results:

• ICP was significantly elevated at 24 hours post-stroke compared to baseline in stroke mice (10.71 ± 6.45 mmHg vs. 3.74 ± 2.20 mmHg, p=0.03).
• Stroke mice exhibited significantly higher ICP at 24 hours compared to sham mice (3.45 ± 1.43 mmHg, p=0.02).
• Edema volumes in stroke mice were minimal (0.04 ± 0.04 mm³), suggesting they did not drive the ICP increase.

Conclusions:

• This study demonstrates an edema-independent elevation in intracranial pressure (ICP) following small ischemic strokes in mice.
• The findings in mice align with previous observations in rats, suggesting a conserved biological response.
• The results point towards a previously undescribed mechanism causing early ICP rise after stroke, irrespective of edema volume.