Gut Microbiota, Bile Acid Metabolism Could be Related to Depression

New research involving the gut microbiota composition could shed light on the risk of patients developing major depressive disorder (MDD).

A team, led by Ning Sun, MD, Department of Psychiatry, First Hospital of Shanxi Medical University, analyzed gut microbiota and bile acids and how they correlate to patient outcomes in regard to major depressive disorder.

Both gut microbiota and metabolite bile acids could play a role in the occurrence and development of major depressive disorder.

The Study

Overall, the study included 31 patients with major depressive disorder and 29 healthy control participants. The investigators collected both blood and fecal samples and determined plasma bile acid content using liquid chromatographic mass spectrometry (LC-MS). In addition they detected gut microbiota by 16SrRNA gene sequencing.

Finally, they analyzed the correlation between different gut microbiota, bile acids, and HAMD scores.

The Association

Overall, the Simpson and Pielou’s evenness index was much higher in the control group than it was in patients with major depressive disorder in the α-diversity analysis.

For the β-diversity analysis, the investigators identified differences in the 2 groups by NMDS analysis, while LEfSe analysis showed 16 different strains. In the bile acid detection, the investigators found significantly higher NorDCA in patients with MDD compared to the control group.

On the other hand, TLCA, GLCA, GDCA, and LCA-3S were significantly lower in the MDD cohort in comparison to the healthy control group.

After conducting a Spearman correlation analysis, the investigators found Turicibacteraceae, Turicibacterales, and Turicibacter were positively related with TLCA, GLCA, GDCA, and TDCA, but negatively correlated with HAMD scores.

However, TLCA, GLCA, and GDCA were all negatively correlated with HAMD scores.

“Gut microbiota and bile acids metabolism are disturbances in MDD, and there exists a correlation between gut microbiota and bile acids metabolism,” the authors wrote. “Moreover, their interaction may be related to the pathophysiological mechanism of MDD.”

Gut Microbiota and Autism Spectrum Disorder

Gut Microbiota can be related to a number of health outcomes.

For example, earlier this year investigators found clear differences in gut bacteria between pediatric patients with autism spectrum disorder (ASD) and pediatric patients without ASD.

A team, led by Xinyan Xie, Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, identified the taxonomic composition and evaluate the changes in the fecal microbiota in Chinese children with ASD.

Patients with ASD had significantly higher relative abundance of Enterobacteriaceae (FDR-P <0.001) at the family level, but a significant reduction of the taxa Monoglobaceae (FDR-P = 0.009).

There were also 12 taxa peculiar in the ASD group, including Hungateiclostridiaceae, Caldicoprobacteraceae, and norank_o__norank_c__Clostridia belonging to the class Clostridia.

For the genera level, Bifidobacterium, Bacteroides, Blautia, Faecalibacterium, and Anaerostipes made up the main part of the gut microbiota in both groups.

However, after correcting for multiple comparisons, the relative abundances at the phylum level of Actinobacteria and Proteobacteria in the study group was significantly higher than those in the control group.

There was also a relative abundance of the Escherichia-Shigella genus in the case group that was significantly higher than the control group. In addition Blautia and unclassified_f__Lachnospiraceae was actually higher in the control group.

The study, “Abnormal gut microbiota and bile acids in patients with first-episode major depressive disorder and the correlation analysis,” was published online in Psychiatry and Clinical Neurosciences.