Stool transplants could improve psychiatric symptoms related to irritable bowel syndrome

According to a Japanese study, stool transplants could improve psychiatric symptoms related to irritable bowel syndrome (IBS) by restoring the balance of the intestinal microbiota. These results widen the scope of application of this therapeutic approach which is currently limited to the treatment of Clostridium difficile infection.

 

Irritable bowel syndrome is a gastrointestinal disorder often associated with depression and anxiety. Concomitance of these three diseases seems to be based on the communication between intestinal microbiota and brain through the gut-brain axis. According to a recent study, patients with depression and irritable bowel syndrome share an imbalance of their intestinal microbiota. This dysbiosis seems to increase intestinal permeability, which could be the source of both these diseases. Stool transplant, a therapeutic approach which is able to restore the balance of the microbiota, has already been tested successfully in patients with gastrointestinal disorders caused by dysbiosis. This approach could thus turn out to be just as effective to treat the associated psychiatric disorders.

Improvement of psychiatric symptoms

In order to test this hypothesis, a team of Japanese researchers completed a stool transplant in 17 patients suffering from diarrhea- or constipation-predominant IBS. Among them, 12 subjects had depression, including 5 associated with anxiety. The analysis of their intestinal microbiota showed lower diversity in case of depression. Stool transplant led to an increase in diversity and abundance of the microbiota in all subjects. After four weeks, the intestinal transit of 9 participants had been restored, both in subjects with associated diarrhea or constipation. Half the depressed patients and most of the patients with anxiety did not have any psychiatric signs. As for the 8 patients whose gastrointestinal symptoms persisted after the transplant, their psychiatric symptoms significantly improved.

Stool transplant: an effective approach

According to the authors, these results suggest that a stool transplant could improve the psychiatric symptoms associated with IBS by increasing the diversity of the bacterial ecosystem in the digestive tract, even when gastrointestinal symptoms do not improve.

 

Sources:

Kurokawa et al. The effect of fecal microbiota transplantation on psychiatric symptoms among patients with irritable bowel syndrome, functional diarrhea and functional constipation: An open-label observational study. Journal of Affective Disorders 235 (2018) 506–512 https://doi.org/10.1016/j.jad.2018.04.038