Potential effects of blueberries on markers of neurodegenerative disease

Abstract

One of the main mechanisms contributing to neurodegenerative diseases (NDD) is oxidative stress, caused by the buildup of reactive oxygen species (ROS) in the brain. Chronic neuroinflammation is also involved with the pathology of NDD; when microglia are activated in response to the dysfunction and aggregation of alpha-synuclein and amyloid-beta, they release inflammatory mediators. NDD are linked to glutamate-mediated excitotoxicity as well, where cells are damaged by the excessive stimulation from glutamate via inadequate uptake by glial cells. Polyphenols, found in very high levels in blueberries, have antioxidant properties which may offer protection and intervention from neurological disorders by managing ROS and reducing the inflammatory response. Biochemical analysis was performed on extracts from frozen wild Newfoundland fruits and leaves, Vaccinium angustiform spp. Mouse-pup derived brain cultures, and pure cultures of rat neurons and microglia were exposed to 100μM glutamate, 100ng/ml alpha-synuclein or 7.5μM amyloid-beta for 24-hours, which decreased cell viability. Overall, there was an increase in the number of viable cells once blueberry extract was added, effectively reducing neuronal and microglial cell death, showing that compounds in berries are beneficial when cell death and damage is influenced by glutamate-mediated excitotoxicity or insoluble alpha-synuclein and amyloid-beta aggregates. The blueberry extracts have high antioxidant activity and therefore may be able to help combat oxidative stress and neuroinflammation in the brain.