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Background: Pharyngeal cooling decreases brain temperature by cooling carotid arteries. This study was designed to evaluate the principle of pharyngeal cooling in monkeys and humans., Methods: Monkeys (n = 10) were resuscitated following 12 min of cardiac arrest. Pharyngeal cooling (n = 5), in which cold saline (5°C) was perfused into the cuff at the rate of 500 ml/min, was initiated simultaneously with the onset of resuscitation for 30 min. Patients (n = 3) who were in an intensive care unit were subjected to 30 min of pharyngeal cooling under propofol anesthesia., Results: In the animal study, core brain temperature was significantly decreased compared with that in the control group by 1.9°C (SD = 0.8, P < 0.001) and 3.1°C (SD = 1.0, P < 0.001) at 10 min and 30 min after the onset of cooling, respectively. The cooling effect was more evident in an animal with low postresuscitation blood pressure. Total dose of epinephrine, number of direct current shocks, and recovery of blood pressure were not different between the two groups. The pharyngeal epithelium was microscopically intact on day 5. In the clinical study, insertion of the cuff and start of perfusion did not affect heart rate or blood pressure. Tympanic temperature was decreased by 0.6 ± 0.1°C/30 min without affecting bladder temperature. The pharynx was macroscopically intact for 3 days., Conclusions: Pharyngeal cooling rapidly and selectively decreased brain temperature in primates and tympanic temperature in humans and did not have adverse effects on return of spontaneous circulation, even when initiated during cardiac arrest in primates.

Background and Purpose: High mobility group box-1 (HMGB1) exhibits inflammatory cytokine-like activity in the extracellular space. We previously demonstrated that intravenous injection of anti-HMGB1 monoclonal antibody (mAb) remarkably ameliorated brain infarction induced by middle cerebral artery occlusion in rats. In the present study, we focused on the protective effects of the mAb on the marked translocation of HMGB1 in the brain, the disruption of the blood-brain barrier (BBB), and the resultant brain edema., Methods: Middle cerebral artery occlusion in the rat was used as the ischemia model. Rats were treated with anti-HMGB1 mAb or control IgG intravenously. BBB permeability was measured by MRI. Ultrastructure of the BBB unit was observed by transmission electron microscope. The in vitro BBB system was used to study the direct effects of HMGB1 in BBB components., Results: HMGB1 was time-dependently translocated and released from neurons in the ischemic rat brain. The mAb reduced the edematous area on T2-weighted MRI. Transmission electron microscope observation revealed that the mAb strongly inhibited astrocyte end feet swelling, the end feet detachment from the basement membrane, and the opening of the tight junction between endothelial cells. In the in vitro reconstituted BBB system, recombinant HMGB1 increased the permeability of the BBB with morphological changes in endothelial cells and pericytes, which were inhibited by the mAb. Moreover, the anti-HMGB1 mAb facilitated the clearance of serum HMGB1., Conclusions: These results indicated that the anti-HMGB1 mAb could be an effective therapy for brain ischemia by inhibiting the development of brain edema through the protection of the BBB and the efficient clearance of circulating HMGB1.