Clazosentan, a novel endothelin A antagonist, improves cerebral blood flow and behavior after traumatic brain injury

The purpose of this study was to test the efficacy of a novel endothelin receptor A antagonist on blood flow and behavioral outcome given 30 minutes following traumatic brain injury.

Male Sprague-Dawley rats (400-450 g) were used in this study. All animals were scanned for initial blood flow using arterial spin labeling magnetic resonance imaging (n = 72 total). Half were subjected to traumatic brain injury using a weight acceleration impact device (n = 36 total). Sham operated animals were used as control (n = 36 total). Thirty minutes following traumatic brain injury, animals were given one intravenous injection of vehicle (0·9% saline) or 1·0 mg/kg clazosentan, a novel endothelin receptor A antagonist, for a total of four groups. At 4, 24, and 48 hours post-traumatic brain injury, blood flow determination continued. On the second day post-traumatic brain injury/sham operation, behavioral testing commenced using a radial arm maze to assess cognitive function.

Our results indicate that 1·0 mg/kg clazosentan was effective in ameliorating hypoperfusion seen after traumatic brain injury. Saline had no effect. Furthermore, clazosentan treatment was effective in significantly improving behavioral outcome following traumatic brain injury.

Collectively, these results indicate that clazosentan, given at 30 minutes post-traumatic brain injury, is effective in improving outcome following injury.