• Can we use gut bacteria to predict how well we are?

    Fecal Microbiota in Pediatric Inflammatory Bowel Disease and Its Relation to Inflammation. Kolho, Kaija-Leena, et al. The American journal of gastroenterology (2015).

    Exploring the relationship between inflammatory bowel disease (IBD) and the microbiota (gut bacteria) has been the topic of intense research activity and has often featured on this blog. It has been shown in numerous studies that microbiota in patients with IBD is different from healthy individuals. Patients with IBD have decreased bacterial diversity and changes in the abundance of certain bacterial groups. However, what the different bacteria do and how changes relate to IBD remains unknown. Stool calprotectin, a protein released into the intestines during inflammation, is currently one of the tests used to monitor disease activity.

    This study investigated the possibility of using microbiota as a tool for monitoring disease activity in IBD. In total, 68 paediatric patients with IBD and 26 healthy controls provided stool and blood samples in a specialist hospital in Finland. 32 received anti-tumour necrosis factor-α (anti-TNFα – Infliximab).

    The scientists observed a change in the microbiota with varying levels of disease. Higher degrees of inflammation were associated with decreased bacterial richness, decreased abundance of Gram-positive bacteria and decreased butyrate producing organisms. Butyrate, a substance released by bacteria, has been shown to have anti-inflammatory effects in the gut and also promotes the growth of friendly bacteria. Moreover, the scientists reported they were able to predict stool calprotectin levels and identify the patients who would respond well to treatment with anti-TNFα from the abundance of certain groups of bacteria. The responders to the anti-TNFα treatment maintained low levels of calprotectin and by week 6 of treatment had increased microbial diversity and similar microbiota to healthy controls.

    The ability to predict the long-term outcome of patients starting anti-TNFα, an expensive treatment with serious side effects is intriguing and immensely desirable. However, it is too early to draw this conclusion as the study was too small and environmental factors including diet, which has been shown to affect the microbiome, were not taken into account in the analysis and interpretation of results.

    Overall, this is a thought-provoking study, which raises a new question – can microbiota be used to predict how patients will respond to treatment? Hopefully, future studies in larger groups and with longer follow-up will explore this aspect in detail and provide an answer.