Reacción a "A study in mice suggests that faecal microbiota transplantation could have unexpected effects on other areas of the digestive system"

This study investigates the possible physiological effects of colonisation of the small intestine by bacteria from the large intestine following faecal transplantation (which mainly includes species from the large intestine). Different regions of the intestine have very different microbiota, and this cross-colonisation could cause alterations. The study primarily investigates this possibility using a model of mice treated with antibiotics that subsequently receive a faecal transplant made from microbiota from different parts of a donor's intestine. The study shows that the entire intestine is colonised from the transplant and not only (although more efficiently) the intestinal region equivalent to the origin. The researchers found that each intestinal region alters metabolites and functions in relation to the microbiota received, and even the gene expression patterns of intestinal tissue and liver cells can change.

The study has some limitations, particularly in the section on human data, where the number of patients analysed is very small (seven). The analyses in mouse models, on the other hand, are very comprehensive and use appropriate techniques.

Given that the microbiota differs depending on the origin of the transplant, it is to be expected that differences will be found at the metabolic and tissue response levels.

The questions that remain open are how long these changes last and whether they are harmful, as suggested by the conclusions. Any alteration of the microbiota, such as that resulting from antibiotic treatment, will have physiological repercussions, and it would be interesting to have some point of comparison beyond the variable origin of the transplant.

The study opens our eyes to how little we still know about the impact of faecal transplantation and proposes exploring combined transplants from multiple sources (omnimicrobial). Overall, more clinical and basic research is needed to understand the true therapeutic potential and possible side effects of faecal transplantation.