Chronic inflammatory bowel diseases

CIBDs progress as inflammatory flareups of variable duration and frequency depending on the patient, alternating with periods of remission. They cause acute abdominal pain, severe diarrhea (between 5 and 10 bowel movements per day), associated with blood and pus in ulcerative colitis (UC); and in severe forms, other symptoms and complications can occur such as fever, tachycardia, nausea and vomiting, weight loss and dehydration. CIBDs also trigger extra-intestinal symptoms, especially articular pain, skin and mucosa lesions (skin ulcerations, mouth ulcers, glossitis, i.e. tongue inflammation...) as well as hepatic and ocular disorders¹³.

Unbalanced microbiota

The gut microbiota analysis of patients with UC revealed they had a decreased diversity of microbial species¹⁴, especially a lower content of Firmicutes and Bacteroidetes. But it is mainly the low content of Faecalibacterium prausnitzii and the excessive content of Proteobacteria and Actinobacteria that are associated with these CIBDs. This imbalance causes a decrease in the production of short-chain fatty acids, beneficial substances which are food to colon cells and play an important role in the regulation of the immune system. That is why fecal microbiota transplant (FMT) has been considered to treat this disorder.

Moderate benefits in UC

Three of the four published clinical trials on UC concluded that this approach was beneficial. Overall, the beneficial effects were much more moderate than they were in the treatment of C. difficile colitis and depend on the donor–which is why donor selection is so important. And several results raise new questions: are only some microorganisms efficient? And if so, which ones? Should the patient receive an enema or an antibiotic therapy beforehand? Which administration route is preferable? Does the restoration of the gut microbiota work long-term or must transplants need to be repeated? These questions need to be answered before fecal microbiota transplant can be seriously considered as an alternative for the treatment of ulcerative colitis.