Gut bacteria research paves way for probiotic depression treatment

Over the years, scientists have strengthened the link between gut bacteria and mental health, among other aspects of one's overall health, indicating that our unique gut bacteria profiles may have a profound effect on psychiatric conditions, such as depression. A new study from Children's Hospital of Philadelphia adds to this body of evidence, detailing the outcome of gut bacteria transplants in lab rats.

In this latest study, researchers detail the results of transplanting gut bacteria from an animal that faces social stressors to an animal that is not stressed. The team found that gut bacteria transplanted from stressed to stress-free rats caused a negative behavioral change in the latter group, underscoring the link between gut microbiome and mental health.

In addition, transplanted gut bacteria was found to induce inflammation in the brains of stress-free rats that had received a bacterial transplant from stressed rats. The inflammation in the first group was the result of stress.

Past research highlights differences in gut bacteria from humans who have psychiatric disorders compared to healthy individuals. Parallels with this data have been made with animal models involving psychiatric issues. In the latest study, researchers found rats that were more vulnerable to stress had higher percentages of select bacteria, including Clostridia, than rats that were resilient to stress.

The gut bacteria changes were achieved via fecal transplants into "naive rats," which were rats that had never been subjected to any stress. The naive rats that received transplants from vulnerable rats displayed behavioral changes associated with depression. Of interest, the team explained anxiety was mostly influenced by neural activity changes triggered by stress, whereas depressive behaviors were more tightly linked to gut bacteria.

The research helps pave the way for potential new depression treatments, ones that may involve the use of probiotics containing specific beneficial bacteria strains.