Brain Chemical Blamed For Old Age Mental Decline Could Hold Key to Its Reversal

https://goo.gl/Z1yEmw

In both C. elegans and humans, the chemical kynurenic acid (KYNA) accumulates with age. As it builds up, KYNA interferes with the activity of glutamate, a brain chemical essential for learning and memory. In humans, it has previously been linked to neurodegenerative disorders, including Alzheimer’s and Parkinson’s disease.
In the study published Jan. 31, 2018, in Genes and Development, researchers looked at the effect of KYNA on the worms’ ability to learn an association between a neutral smell and food.

The researchers found that by keeping KYNA levels low throughout the worm’s life, they could prevent the onset of age-related decline – the worms kept learning. In older worms already impaired, lowering KYNA levels could counteract the impairments – raising hope that interventions later in life may be effective in reversing neurological decline.

The reason that KYNA increases with age is still a mystery, but the new study offers an intriguing hint, by linking KYNA buildup in aging worms to elevated levels of insulin, a hormone that controls blood sugar in both worms and humans. In contrast, earlier experiments by Ashrafi’s team had found that fasting, which has been linked to longevity, reduced levels of KYNA in worms and improved learning and memory.

Ashrafi thinks that KYNA is the linchpin through which fasting makes the brain better at learning, while aging makes it worse. “These are two sides of the same coin,” he said.