Abstract T P96: Controlled Brain Glucose Uptake and Metabolism by Ethanol: An Alternative Approach in Improving Stroke Outcome

Abstract

Introduction: Post-stroke oxygen deficit impairs oxidative phosphorylation of glucose. Surviving brain cells increase anaerobic glycolysis (hyperglycolysis) promoting reactive oxygen species (ROS) synthesis via lactic acidosis and NADPH oxidase (NOX) activation. Hyperglycemia present in 40% of stroke patients with or without diabetes perpetuates hyperglycolysis. Insulin, the only treatment to attenuate hyperglycemia-induced hyperglycolysis, is linked to increased risk of hypoglycemia and mortality. We showed that EtOH reduced ROS-mediated brain damage. Here, we studied whether hyperglycemia/hyperglycolysis-enhanced brain injury are ameliorated by reducing brain glucose uptake and metabolism rather than affecting blood glucose levels. Methods: Sprague-Dawley rats underwent a 2 h right middle cerebral artery occlusion (MCAO). EtOH (1.5 g/kg) or saline was injected IP upon reperfusion, then sacrificed 3 and 24 h later. Energy stores, hyperglycolysis-associated glucose uptake and metabolism, lactic acidosis, and oxidative stress were assessed via ADP/ATP ratio, NAD+/NADH ratio, Na+/K+ ATPase activity, levels of brain and blood glucose, glucose transporter GLUT 1 and 3, lactate, lactate dehydrogenase (LDH), ROS, phosphofructokinase-1 (PFK-1), NOX, and PFK-1 and NOX activity. Results: Ischemic rats showed significant (p<0.01) increase in ADP/ATP and NAD+/NADH ratios, and decrease in Na+/K+ ATPase activity indicating impaired metabolic and neural activity. Increased blood glucose and decreased brain glucose indicate hyperglycemic condition with hyperglycolysis. High levels of GLUT 1 and 3, lactate, LDH , PFK-1, NOX, and ROS support ROS associated hyperglycolysis. EtOH normalized these metabolic parameters to control levels, but only blood glucose remained higher. In sum, EtOH attenuates hyperglycemia-enhance brain injury by reducing glucose uptake and its hyperglycolytic-mediated metabolism under hyperglycemic condition. Conclusion: EtOH administered upon reperfusion is neuroprotective against ROS-mediated brain damage in acute ischemic stroke. It attenuates hyperglycemia-enhanced hyperglycolysis at the level of glucose uptake, utilization, and metabolism rather than reducing serum glucose levels.