Hyperthermia and hypermetabolism in focal cerebral ischemia

The reliable and reproducible creation of an animal model of focal cerebral ischemia is not easily accomplished. Using a transortibal approach, we showed that occlusion of the posterior cerebral artery (PCA), middle cerebral artery (MCA), and the contralateral anterior cerebral artery (ACA) created a large cortical and subcortical stroke in the non-human primate (NHP). Subsequently, we created the same stroke endovascularly in the NHP. Using the endovascular stroke model in the NHP, we measured brain temperature with thermocouples and cerebral blood flow (CBF) by stable xenon CT in one NHP, and CMRO₂ and CBF by positron emission tomography (PET) in another NHP. Two female non-human primates (M. mulatta) weighing 7.0 and 8.0 kg, respectively, were studied under fentanyl-diazepam anesthesia with continuous monitoring of arterial blood pressure, rectal temperature, and end-tidal CO₂ with intermittent blood gas measurements. Using an endovascular approach, the PCA (P2), MCA (M1), and the ICA at the bifurcation and contralateral ACA produced a large hemispheric stroke. In the right ischemic hemisphere, temperatures increased by 2°C-3°C. PET measurement of CBF and CMRO₂ showed that CMRO₂ increased in the region of the ischemic stroke. We found that both hyperthermia and hypermetabolism occur in acute stroke.