A one-stop shot for stress?
A new study out of the University of Colorado suggests that it could be that easy — if future clinical trials replicate the results that scientists there recently published in the journal Brain, Behavior and Immunity.
The CU Boulder study found that immunization with beneficial probiotic bacteria can have long-lasting anti-inflammatory effects on the brain, making it more resilient to stress.
The bacterium in question is called Mycobacterium vaccae, and it lives naturally in soil. It was first discovered by immunologists in the 1990s on the shores of Lake Kyoga in Uganda, according to a CU Boulder news release.
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The findings of lead author Matthew Frank and his team mean a "stress shot" could become as common as the flu shot is now. Patients could potentially walk into the doctor's office, get the shot and exhibit fewer physical signs of stress associated with post-traumatic stress disorder, anxiety or depression.
"We found that in rodents this particular bacterium, Mycobacterium vaccae, actually shifts the environment in the brain toward an anti-inflammatory state," Frank, a senior research associate in CU Boulder's psychology and neuroscience department, said in the release. "If you could do that in people, it could have broad implications for a number of neuroinflammatory diseases."
It's that stress-induced inflammation in the brain that boost the risk associated with those disorders.
"There is a robust literature that shows if you induce an inflammatory immune response in people, they quickly show signs of depression and anxiety," Frank said. "Just think about how you feel when you get the flu."
Specifically, Frank's team found that male rats injected with M. vaccae three times had increased level of an anti-inflamatory protein in the hippocampus — the brain region responsible for regulating cognitive function, anxiety and fear — a full eight days after the final injection. They also showed lower levels of a stress-induced protein called alarmin.
The immunized rats also physically showed less anxious behavior.
Senior author Christopher Lowry said in a news release that he envisions a day when M. vaccae could be given to people at high risk of PTSD — such as troops awaiting deployment or emergency room doctors and workers — to shield them against the effects of stress on the brain and body.