Can the gut microbiota be used to better predict responses to IBD treatment?

Crohn’s disease and ulcerative colitis are both forms of IBD and have one thing in common: they cause uncontrolled inflammation of the lining of a section of the digestive tract, resulting in various symptoms during inflammatory flares. While there is currently no cure for these diseases, there are treatments such infliximab (sidenote: Infliximab A biotherapy that neutralizes TNF-α, the protein responsible for tissue inflammation. ) (IFX) aiming at reducing inflammation. However, a third of patients do not respond to this therapy and there is currently no biomarker (sidenote: Biomarker An objectively measured biological characteristic that makes it possible to evaluate responses to treatment. This response can be complete or partial. )  that predicts response to treatment. The researchers in this study may have found the answer in the gut microbiota.

Gut microbiota differs before treatment...

Numerous studies have shown a link between the composition of the gut microbiota (bacteria and, more recently, fungi) and IBD. Therefore, in order to identify markers that predict response to IFX therapy, the researchers evaluated the impact of IFX treatment on the gut microbiota composition of 72 IBD patients (sidenote: 25 patients with Crohn’s disease (CD) and 47 with ulcerative colitis (UC). ) . Bacterial and fungal diversity in the gut microbiota was analyzed using fecal samples collected before treatment and 1 year after beginning of therapy. The patients were classified into three groups according to their response to treatment. The study revealed that the bacterial and fungal profiles of the three groups differed significantly before start of therapy.

...offering a predictive tool

Significant differences between the three groups of patients were also observed after initiation of treatment: non-responders had lower contents of anti-inflammatory bacteria and higher contents of pro-inflammatory bacteria and fungi (such as the genus Candida) compared with responders. These results suggest that the gut microbiota is involved in responses to treatment.

Based on these findings, the researchers subsequently identified certain bacteria and fungi present in the gut before start of treatment which could be used to predict responses to IFX therapy. Early identification of non-responders would permit rapid modification of treatment, limiting side effects and reducing the costs involved. A fully positive approach!