A CU Boulder-led study showing that injecting beneficial bacteria into mice can make them more resilient to stress has been named among the 鈥渢op 10 advancements and breakthroughs鈥� of 2016 by the nation鈥檚 leading non-governmental funder of mental health research.
Now, lead author Christopher Lowry, an associate professor in the Department of Integrative Physiology, is moving forward with clinical trials to see if altering the microbiome, or composition of resident bacteria, in military听veterans with posttraumatic stress disorder can be beneficial.
Christopher Lowry, an associate professor in the department of integrative physiology.
鈥淭here is a growing recognition that the microbiome can impact health in general and, more specifically, mental health,鈥� said Dr. Jeffrey Borenstein, president of the Brain and Behavior Research Foundation, which this week announced its Top 10 breakthroughs. 鈥淒r. Lowry鈥檚 work can potentially be a game-changer in our understanding of this, and could ultimately lead to new treatments.鈥�
The study, published in the Proceedings of the National Academy of Sciences (PNAS) in May, found that when healthy mice were injected with a heat-killed preparation of Mycobacterium vaccae and placed with a larger aggressive male for 19 days they exhibited less anxiety or fear-like behaviors and behaved more proactively around their aggressor. They were also 50 percent less likely to suffer stress-induced colitis (as measured by cellular damage to the colon) and showed less system-wide inflammation.
Meanwhile, treatment with M. vaccae increased expression of tph2, an enzyme involved in the biosynthesis of the neurotransmitter serotonin in the brain. Previous studies have shown that M. vaccae increases serotonin in the prefrontal cortex, which modulates anxiety.
鈥淥ur study in PNAS showed we can prevent a PTSD-like syndrome in mice,鈥� said Lowry, who has been studying Mycobacterium vaccae鈥檚 impact on the brain for 16 years.
The bacterium was first discovered on the shores of Lake Kyoga in Uganda in the 1970s by immunologist听John Stanford after recognizing that people who lived in the area responded better to certain leprosy vaccines. They later realized that the bacterium found in the lakeshore soil had immune-modulating properties that were enhancing the vaccine鈥檚 efficacy.
In 2004, studies in lung cancer patients showed that while the bacterium didn鈥檛 prolong life, it did improve emotional health.
Ever since, Lowry has been working to figure out how.
He and others suspect the 鈥渉ygiene hypothesis鈥� is at play. It suggests that modern sanitary measures, antibiotic overuse and dietary changes have reduced exposure to anti-inflammatory, immune-modulating bacteria naturally present in the environment.
By re-introducing such 鈥渙ld friends,鈥� Lowry theorizes, a host of inflammatory diseases 鈥� including psychiatric disorders 鈥� could be quelled.
The Brain and Behavior Research Foundation selects its Top 10 from more than 500 scientists who receive its NARSAD (National Alliance for Research in Schizophrenia and Affective Disorders) awards each year.
鈥淭his NARSAD recognition reflects the fact that this idea is not science fiction to people anymore,鈥� said Lowry. 鈥淭here is a level of acceptance that did not exist 10 years ago.鈥�
Mycobacterium vaccae under the microscope.
In June, with funding from the Department of Veterans Affairs, Lowry and his colleague Lisa Brenner, an associate professor of psychiatry at the University of baby直播app Denver School of Medicine, launched a study that will include 40 baby直播app veterans diagnosed with PTSD and co-occurring mild traumatic brain injury. One group will be given an oral probiotic consisting of a different bacterial strain, Lactobacillus reuteri, for eight weeks. The other will take a placebo. They鈥檒l be subjected to a stressful situation (giving a speech in front of a group). Then physiological and perceived stress measures will be collected.
Meanwhile, Lowry is doing more animal studies to determine precisely how M. vaccae influences behavior 鈥� likely by dampening down inflammation in the brain. He is also working to obtain Investigational New Drug (IND) status for M. vaccae in hopes of conducting a clinical trial testing its potential to prevent or treat mental health disorders.
Ultimately, he believes the bacteria 鈥� via pill, inhalation or injection 鈥� could be given to people at high risk of PTSD - such as soldiers preparing to be deployed or emergency room workers - 听to buffer the physical and behavioral side-effects that can result from high stress.
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