Abstract P781: Ischemic Postconditioning Protects Against Hemorrhagic Transformation Induced by Hyperglycemia in Ischemic Stroke

Abstract

Background: Hyperglycemia occurs in over 40% of ischemic stroke patients, which induces hemorrhagic transformation (HT) and worsens stroke outcomes. The management of hyperglycemia with insulin did not show favorable outcomes. Thus, strategies for managing hyperglycemia-exacerbated stroke injury are urgently needed. We previously demonstrated that ischemic postconditioning (IPostC) (repeated transient interruption of cerebral blood flow during reperfusion) can reduce brain infarct size and improve neurological outcomes. In this study, we hypothesized that IPostC can reduce HT in ischemic stroke with acute hyperglycemia. Method: Male mice were subjected to middle cerebral artery occlusion (MCAO) for 1 hour, followed by reperfusion to mimic ischemic stroke. Glucose was injected before MCAO to induce hyperglycemia. IPostC was initiated upon reperfusion with 3 cycles of 30-second reperfusion followed by 10 seconds of MCA occlusion. Brain infarct was visualized by TTC staining and quantitated using Image J. Hemorrhagic transformation was evaluated by hemorrhagic scores. Result: Acute hyperglycemia significantly increased the brain infarct size (by 25%, p<0.01), brain edema (p<0.001) and hemorrhagic transformation (HT) (average HT scores: 0.75 in MCAO group vs 15.6 in MCAO plus hyperglycemia group, p<0.001), Mice with hyperglycemia also exhibited more severe neurological deficit and higher mortality rate at 24 hours after MCAO. 2) IPostC treatment significantly reduced brain infarct size (p<0.01), brain edema (p<0.05) and attenuated HT (p<0.001). Neurological deficit and mortality rate was reduced with IPostC treatment. Conclusion: Our findings suggest that IPostC can counteract the effects of acute hyperglycemia and reduce brain injury, edema and HT after stroke. Grant/Other Support: NIH Grant R01NS064136C