Research brief: Targeting inflammation in suicide risk
August 2, 2016
New findings published today in the journal Translational Psychiatry shed new light on the biological underpinnings of suicide risk and may even lead to new ways to biologically monitor risk. Here’s a quick snapshot of the work.
There are more than 800,000 deaths by suicide around the world annually, according to the World Health Organization. Mounting evidence points to inflammation as a key factor in elevating suicide risk.
Over the course of two years, a collaborative research team from Sweden, the U.S. and Australia measured the amount of an enzyme called ACMSD in the blood and spinal fluid of people who had attempted suicide as well as a control group with no history of suicide attempts.
The team found that people who had attempted suicide had lower ACMSD activity, meaning the enzyme didn’t produce enough of an important chemical called picolinic acid, which helps keep levels of an inflammatory chemical called quinolinic acid in check.
The levels of these chemicals may one day be used as biomarkers, or biological indicators, for suicide risk. At the same time, fixing deficiencies in ACMSD presents a promising treatment target.
TERMS TO KNOW
Inflammation: Put simply, inflammation is the body’s response to an injury, infection or other insults. During this process, inflammatory chemicals are released to help the body either heal and fight off invading pathogens. However, when the mechanisms that keep inflammatory responses in check go awry, these chemicals can be overproduced, leading to a negative effect.
ACMSD: ACMSD is an enzyme, a type of protein that facilitates important reactions and processes throughout the body. Although there is still much to be learned, early evidence indicates ACMSD may play a key role in other psychiatric conditions as well.
Tryptophan and the kynurenine pathway: Tryptophan is one of nine important amino acids that humans cannot produce and that must be acquired through diet. More than 90 percent of tryptophan is broken down via the kynurenine pathway. During this process, quinolinic acid and picolinic acid are formed.
Quinolinic (QUIN) and picolinic (PIC) acids: The production of quinolinic acid, which is inflammatory, is limited by ACMSD through the production of picolinic acid. In the new findings, elevated levels of quinolinic acid and lower levels of picolinic acid were associated with an increased risk of suicide.