Fecal Microbiota Transplantation in Irritable Bowel Syndrome: New Horizons in Treatment

 In this article, we present and explain key questions and answers that may be most helpful for patients with Irritable Bowel Syndrome (IBS), especially those interested in the innovative approach of Fecal Microbiota Transplantation (FMT). The information is entirely based on the publication "Faecal Microbiota Transplantation in Irritable Bowel Syndrome: a Randomised, Double-blind Cross-over Study Utilising Mixed Microbiota From Healthy Donors"—one of the few studies that strictly follow the international diagnostic criteria (Rome IV) and apply European standards for donor selection. The team behind this publication consists of researchers and medical professionals specializing in gastroenterology, microbiology, and clinical trials, aiming to provide science-based answers to patient questions and support informed decision-making for treating IBS.

“Altering gut microbiota through transplantation from healthy donors may relieve IBS symptoms and offer a new chance for a better quality of life.”

Expert Perspectives

Irritable Bowel Syndrome (IBS) is one of the most common functional gastrointestinal disorders, affecting about 10% of the adult population in Europe. The causes of IBS remain unclear, but growing literature points to the gut microbiome as playing a key role in the development and expression of the condition. In recent years, interest has increased in Fecal Microbiota Transplantation (FMT) as a potential innovative treatment approach for IBS, particularly in cases with diarrhea-predominant or mixed-type symptoms. Here we present five expert insights and quotes to help patients and their families better understand the new possibilities and scientific perspectives on this topic.

1. What is Fecal Microbiota Transplantation (FMT), and why is it considered a potential treatment for IBS?

“Modification of patients’ colonic microbiota might ameliorate the condition.”

Explanation: FMT is a procedure in which fecal material from healthy donors with high microbial diversity is introduced into the intestines of a patient. This can help restore the disrupted microbial balance in people with IBS and lead to symptom relief. The idea is that a healthy and diverse microbiota positively impacts gut function.

2. Why are the source and quality of the microbiota important in FMT?

“The active intervention substance is a mixed stool microbiota derived from healthy individuals, screened for infectious diseases according to European consensus conference on faecal microbiota transplantation guidelines, and who were preselected for high alpha diversity of their microbiome and distance in community ordination from IBS patients microbiota.”

Explanation: Only specially selected donors—healthy individuals with exceptionally diverse microbiomes—are chosen for this procedure. This ensures safety and effectiveness by minimizing the risk of transmitting infections and increasing the chance of a positive treatment outcome.

3. What scientific approach is used to evaluate the effectiveness of FMT in IBS?

“Three-groups, double-blind, placebo-controlled, randomised, cross-over study in adult patients diagnosed with IBS (diarrhoeal or mixed form) according to Rome IV criteria.”

Explanation: This type of clinical trial is considered the gold standard in medicine—it ensures objectivity and minimizes bias. The study includes three groups of patients and uses a double-blind design (neither patients nor doctors know who is receiving the active treatment), placebo control (comparing the active treatment to an inactive version), randomized assignment, and treatment crossover. This structure provides highly reliable results.

4. What is the role of the placebo control, and how does it differ from the active treatment?

“Placebo is the same mixture, inactivated by autoclaving.”

Explanation: The placebo group receives the same donor material, but it has been autoclaved—sterilized and inactivated—so it contains no live microorganisms. This allows researchers to determine whether any benefits are due to the live microbes themselves and not to other factors, such as the psychological effects of undergoing a medical procedure.

5. For which patients and under what conditions is FMT appropriate, according to current research?

“Study in adult patients diagnosed with IBS (diarrhoeal or mixed form) according to Rome IV criteria.”

Explanation: Current studies apply FMT in adult patients diagnosed with diarrhea-predominant or mixed-type IBS based on strict diagnostic criteria (Rome IV). It is not suitable for every patient—an individual approach and consultation with a specialist gastroenterologist are essential.

Key Sources:

• Original publication: Faecal Microbiota Transplantation in Irritable Bowel Syndrome: a Randomised, Double-blind Cross-over Study Utilising Mixed Microbiota From Healthy Donors.

• European recommendations for fecal microbiota transplantation.

• Scientific literature on the role of the microbiome in IBS:

  • John F. Cryan et al., “The Microbiota-Gut-Brain Axis,” Physiological Reviews, 2019.

  • P. D. C. Déry et al., “Fecal Microbiota Transplantation: Current Applications, Effectiveness, and Future Perspectives,” Clinical Microbiology Reviews, 2021.

Questions & Answers

1. What type of IBS is included in the study, and can I participate if I have constipation? 

Answer: The study includes only adult patients diagnosed with diarrhea-predominant or mixed-type IBS according to Rome IV criteria. If you have constipation-predominant IBS, this specific protocol does not apply, as it focuses on diarrhea and mixed forms.

2. How many FMT procedures are performed during the study? 

Answer: Each participant undergoes a total of four FMT procedures (enemas)—two pairs of treatments, with an eight-week break between the pairs. This schedule allows researchers to track the intervention’s effects and whether they are long-lasting.

3. How is the fecal microbiota donor selected? 

Answer: Donors are healthy individuals selected based on the high alpha diversity of their microbiome and a significant difference in their microbial profile compared to IBS patients. They are also rigorously screened for infectious diseases following European standards.

4. In what form is the transplantation administered, and is there a group that receives only placebo? 

Answer: The procedure is administered via enemas—that is, through the rectum. The study includes a group of patients who receive only inactivated (autoclaved) microbial material as a placebo, to compare its effects with those of the active transplantation.

5. What does “double-blind” mean, and why is it important for patients? 

Answer: “Double-blind” means that neither the patients nor the physicians know who is receiving the active treatment and who is receiving the placebo during the study. This ensures that the results are objective and not influenced by participants’ or researchers’ expectations.

Conclusion

Fecal Microbiota Transplantation (FMT) is emerging as one of the most promising innovative approaches for treating specific forms of Irritable Bowel Syndrome. Although the procedure remains under close clinical investigation, it clearly follows well-established medical and scientific standards aimed at ensuring maximum safety and effectiveness for patients. We hope that the questions and answers presented here, based on a reputable scientific publication, will help patients and their families better understand the topic and engage in more informed conversations with their healthcare providers.

Source: Faecal Microbiota Transplantation in Irritable Bowel Syndrome: a Randomised, Double-blind Cross-over Study Utilising Mixed Microbiota From Healthy Donors https://pubmed.ncbi.nlm.nih.gov/37834010/