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.