Intracranial pressure elevation after ischemic stroke in rats: cerebral edema is not the only cause, and short-duration mild hypothermia is a highly effective preventive therapy

Murtha, L. A., McLeod, D. D., Pepperall, D., McCann, S. K., Beard, D. J., Tomkins, A. J., Holmes, W. M. , McCabe, C. , Macrae, I. M. and Spratt, N. J. (2015) Intracranial pressure elevation after ischemic stroke in rats: cerebral edema is not the only cause, and short-duration mild hypothermia is a highly effective preventive therapy. Journal of Cerebral Blood Flow and Metabolism, 35, pp. 592-600. (doi: 10.1038/jcbfm.2014.230) (PMID:25515213)

Abstract

In both the human and animal literature, it has largely been assumed that edema is the primary cause of intracranial pressure (ICP) elevation after stroke and that more edema equates to higher ICP. We recently demonstrated a dramatic ICP elevation 24 hours after small ischemic strokes in rats, with minimal edema. This ICP elevation was completely prevented by short-duration moderate hypothermia soon after stroke. Here, our aims were to determine the importance of edema in ICP elevation after stroke and whether mild hypothermia could prevent the ICP rise. Experimental stroke was performed in rats. ICP was monitored and short-duration mild (35 °C) or moderate (32.5 °C) hypothermia, or normothermia (37 °C) was induced after stroke onset. Edema was measured in three studies, using wet–dry weight calculations, T2-weighted magnetic resonance imaging, or histology. ICP increased 24 hours after stroke onset in all normothermic animals. Short-duration mild or moderate hypothermia prevented this rise. No correlation was seen between ΔICP and edema or infarct volumes. Calculated rates of edema growth were orders of magnitude less than normal cerebrospinal fluid production rates. These data challenge current concepts and suggest that factors other than cerebral edema are the primary cause of the ICP elevation 24 hours after stroke onset.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Macrae, Professor Mhairi and Murtha, Ms Lucy and Holmes, Dr William and McCabe, Dr Chris
• Authors: Murtha, L. A., McLeod, D. D., Pepperall, D., McCann, S. K., Beard, D. J., Tomkins, A. J., Holmes, W. M., McCabe, C., Macrae, I. M., and Spratt, N. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Journal Name: Journal of Cerebral Blood Flow and Metabolism
• Publisher: Nature Publishing Group
• ISSN: 0271-678X
• ISSN (Online): 1559-7016