Scientists have isolated a unique molecular model that could someday help create a "stress vaccine" – and they found it hidden in a bacteria that thrives in dust.
Mycobacterium vaccae is a non-pathogenic bacterium that lives in soil and has shown great promise in health research; now, a new study may have finally understood why.
The results suggest that a specific type of fat in the interior M. vaccae could be the reason why exposure to this seemingly beneficial bacteria in the soil can be good for us.
This work joins the idea of "old friends", a hypothesis that man would have co-evolved with a group of useful microorganisms, and the loss of these links in the world. Modern environment has resulted in an increase in the number of allergic and autoimmune diseases.
"The idea is that since humans have moved away from farms and agriculture and hunter-gatherers to settle in cities, we have lost contact with organizations serving regulate our immune system and suppress inappropriate inflammation, "says neuroendocrinologist Christopher Lowry.
"This put us at a higher risk of inflammatory disease and stress-related psychiatric disorders."
Lowry did some research M. vaccae For years, a previous study had revealed that an injection of mice with a heat-killed bacterium preparation prevented the occurrence of stress-induced reactions in animals.
But until now, nobody really knew what it was M. vaccae who could be responsible for such effects.
"One of the burning questions is, essentially, what are the critical components of the bacteria that seem to benefit the host?" Lowry said The Denver Post.
In the new study, researchers chemically isolated and synthesized a fatty acid called 10 (Z) -hexadecenoic acid, which seems to indicate how the bacterium can reduce inflammation in other animals.
At the molecular level, the lipid appears to act by binding to receptors called peroxisome proliferator activated receptors (PPARs). In doing so, it inhibits the pathways of inflammation, at least in the immune cells of experimentally treated mice.
"It seems that these bacteria that we've evolved have a knack for," Lowry said.
"When they are absorbed by the immune cells, they release those lipids that bind to that receptor and block the inflammatory cascade."
Much remains to be done to see if the same effect could be replicated in humans. If so, the researchers say this discovery could eventually help develop a "stress vaccine" to help people in high-stress occupations who are at risk of developing post-traumatic stress disorder.
It's still a long way off, as is currently being researched. Lowry is rather optimistic, believing that it may only be 10 to 15 years before such treatment is available; if he is right, we will have insects in the mud to thank.
"We used to think that microbacteria were not an important part of the human microbiome," Lowry said. The Denver Post.
"The power of nature continues to amaze and surprise us as scientists and we look forward to learning more."
The results are reported in psychopharmacology.