Fecal microbiota transplantation in patients with irritable bowel syndrome

Irritable Bowel Syndrome (IBS) is a common disorder with multifactorial pathophysiology.In these mechanisms alterations in the gut microbiota (dysbiosis), now called the microbiota-gut-brain axis, have been considered.Dysbiosis has been the focus of treatment including probiotics, luminal antibiotics, and fecal microbiota transplantation (FMT).Therefore, the current paper aimed at reviewing the data on FMT in IBS.We conducted a search on PubMed using the terms Fecal transplantation OR Fecal microbiota transplantation, AND Irritable bowel syndrome OR IBS.We found contradictory results as there is no standardization for the FMT protocol.However, many studies showed it improved gastrointestinal symptoms, fatigue, anxiety, depression, and quality of life.An adequate clinical response correlated with an increased microbial diversity, Firmicutes/Bacteroidetes ratio, and in Bacteroidetes, and Prevotella populations; a decrease in Proteobacteria, Actinobacteria and Bacteroides, and dysbiosis index, and a transition from the patient's -diversity to one more like that of the donor, and a reduction of sulfate-producing bacteria.Also, there is a relationship between symptom improvement and increased densities of enteroendocrine cells, and some short chain fatty acids such as butyric and isobutyric acids.Allogenic FMT induces the expression of genes related to the immune response at the mucosal level, while autologous FMT induces genes related to metabolism.In conclusion, FMT is a potential treatment for IBS with benefits and safety in the long-term.However, the protocol needs standardization, and characterization of response predictors such as the IBS subtypes, the receptors and donor's microbiota composition, and the presence of post-infection vs. non-post infectious IBS.