Multi-omics analysis of fecal microbiota transplantation's impact on functional constipation and comorbid depression and anxietyOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study tested whether fecal microbiota transplantation (FMT) can relieve functional constipation alongside comorbid depression and anxiety, and explored the mechanism. Patients received donor stool via a nasointestinal tube over two treatment courses. Bowel and psychiatric symptoms were scored before and four weeks after FMT. Gut microbiota were profiled by metagenomic sequencing, serum neurotransmitters by targeted metabolomics, and serotonin biosynthesis was tested in QGP-1 enterochromaffin cells exposed to patient fecal supernatant.
Who was studied?
The cohort was four patients with functional constipation plus depression and anxiety, all women, at a hospital in Taiyuan, China. Mean age was 64 years, with an average 12 years of constipation and 7 years of depression. Stool came from four screened healthy donors, mean age 27. This was a small, single-center, open-label, nonrandomized human study. Constipation and mood were assessed with validated scales including KESS, HAMD, and HAMA.
What were the most important findings?
After FMT, constipation, depression, and anxiety all improved significantly. HAMD scores fell from 38.5 to 7.25 and HAMA from 39.0 to 13.75, with stool form shifting from Bristol type II to type IV. At the genus level, Bacteroides and Klebsiella decreased while Lactobacillus and Selenomonas increased. Serum serotonin (5-HT) dropped about 13-fold, from 368 to 27 nmol per liter. Klebsiella sp. 1_1_55, Odoribacter splanchnicus, and Ruminococcus gnavus CAG:126 correlated positively with serotonin levels.
What are the greatest implications of this study?
The results suggest FMT can ease both gut and mood symptoms in constipated patients with psychiatric symptoms, possibly by remodeling the microbiome and lowering peripheral serotonin. Patient fecal supernatant raised serotonin synthesis in cultured cells, linking specific bacteria to the serotonin pathway. With only four patients and no placebo control, causation cannot be established. The authors call for large, double-blind, randomized, placebo-controlled trials to confirm these effects.