Ellie Levi, 

Title:

THE RELATIONSHiP BETWEEN CEREBRAL BLOOD FLOW AND FUEL METABOLISM: DOES LOW FLOW DRIVE THE DISAPPEARANCE OF AEROBIC GLYCOLYSIS?

Abstract:

Both Glucose and Oxygen are necessary for brain energy metabolism in a 1:6 ratio. These substrates are extracted from venous circulation to feed the brain, which has little to no storage for these substrates (unlike other muscles). Cerebral blood flow (CBF), brings these substrates to the brain and varies greatly between healthy humans, requiring the substrate extraction rates to compensate for slower or faster flow. To compensate, glucose can undergo aerobic glycolysis (AG), which is the metabolism of glucose without oxygen, despite an abundance of oxygen. However, this is a less effective metabolic pathway. As the brain moves from resting to active, there is a disproportionate uptake of oxygen to glucose, showing AG increases with CBF. This phenomenon is known as neurovascular coupling. Despite this, oxygen decreases with neurovascular coupling. With a variation in CBF rates from 500mL - 1500mL, it was observed that more oxygen is extracted when the brain is at rest, while glucose remains at a fairly constant rate. This shows us that glucose fails to adapt to varying energetic needs in the brain, which has implacations of poor brain health in the future. Although there is not certain proof yet, the lack of glucose variation displays similar pathways of those who have neurodegenerative diseases.