Larger-than usual amounts of quinolinic acid appear to be a viable biomarker for severe depression, Australian researchers have concluded, and they're using it as the basis for a blood test now under development to gauge high suicide risk.
As the Australian Times reports, the team from the University of New South Wales has long looked at quinolinic acid and its connections to depression. In small quantities, quinolinic helps repair DNA, and produce energy through an essential co-factor known as NAD+. But the team previously found that quinolinic acid in larger-than-normal quantities can behave like a neurotoxin as it binds to NMDA neuronal receptors. Brain cells become excited and patients become severely depressed and suicidal, they found. How did they measure this? Through gas chromatography-mass spectrometry, which helped quantify quinolinic acid in samples from suicidal patients.
More research needs to be done, but the notion of finding a way to harness quinolinic acid as a viable biomarker for depression or suicidal tendencies would be a great advance in the field where researchers have long focused on measuring levels of the brain chemical serotonin to gauge depression.
The researchers are serious about moving forward. They're working with an unnamed biotech, according to the article, and hope to have a working blood test ready for human clinical trials within the next 12 months. Such a test, they said, would process results within two days. And, they noted, it could also open the door to personalized medicine treatments focused specifically on reducing quinolinic acid levels to help address alleviate severe depression.
Others, as reported in the Australian Associated Press, see such a test as a research tool, one that could explore the connection between high levels of quinolinic acid and conditions such as Alzheimer's disease and schizophrenia, as well as depression and suicidal states.