Gut flora changed in patients with bipolar depression

A recent study on the gut microbiota changes in Chinese adolescent patients with bipolar depression sheds light on BD diagnosis and treatment outcome. The relevant finding was published online in the journal of Advanced Science on May 15.

BD is a chronic and recurrent disease which has captured increasing attention in the globe. BD is associated with severe impairment in cognitive and social functions, and increased risk of disability and suicide, especially in young individuals. Due to the fact that BD patients are marked by extreme emotional instability, varieties of symptoms and recurrence of the disease, getting an accurate diagnosis tends to be elusive. Early discoveries and definitive diagnoses thus become a hard nut to crack in the field of BD research.

The research team led by Prof. XU Yi and Prof. HU Shaohua from the First Affiliated Hospital of School of Medicine engaged in an analysis of 16S-ribosomal RNA gene sequences of a total of 52 BD patients and 45 healthy controls (HCs). It revealed that gut microbial composition and diversity were significantly different between BD patients and HCs, with greater gut microbial diversity in HCs, as estimated by Obs, Chao 1, and ICE index, compared with untreated BD patients. Permutational ANOVA test was employed to validate the results from LDA effect size (Lefse) analysis and found that Bacteroidetes phylum, Parabacteroides, Bacteroides, and Halomonas genera were greatly enriched in BD patients, while Firmicutes phylum, Roseburia, Faecalibacterium, and Coprococcus genera were consistently higher in HCs. At the genus level, Klebsiella, Lactobacillus, Anaeroglobus, Collinsella, Paraprevotella, Solobacterium, and Veillonella were enriched in treated BD patients, while Alistipes abundance was higher in untreated BD patients. Permutational ANOVA test showed higher Klebsiella and Veillonella in treated BD patients and no difference in terms of phylum between untreated and treated patients.

Microbial composition changed following quetiapine treatment in BD patients. Notably, 30 microbial optimal Operational Taxonomy Units (OTUs) marker were identified on a random forest model and achieved an area under the curve (AUC) of 0.81 between untreated patients and HCs. Ten microbial markers were identified with the AUC of 0.93 between responder and nonresponder patients.

This study characterizes the gut microbiota in BD and is the first to evaluate microbial changes following quetiapine monotherapy. Gut microbiota‐based biomarkers may be helpful in diagnosing BD and predicting treatment outcomes.