Scientists now know that the gut microbiota – the microorganisms found in the human gastrointestinal tract – have a role to play in inflammatory bowel diseases (IBDs). The exact role of the microbiota is still unclear, though. Are IBDs caused by having a disrupted microbiota? Are they the result of some ‘perfect storm’ of genes and microbiota? Or do the microbiota have no causal role to play, simply changing in response to the onset of an IBD?
Some studies have found differences in microbiota composition between those with IBD and healthy controls – that is, certain bacteria are over-represented or missing in the IBD cohort. But these say nothing about causality (let alone accounting for variability of each person’s microbiota over time), so they’re only the beginning of the story. Furthermore, geography seems important. A recent study that examined those with IBD across European and Asian countries found distinct patterns of microbes in IBD sufferers from each location, but also some microbial biomarkers for IBD that held across all geographic locations (such as a decrease of Faecalibacterium).
Another avenue of research is examining the interplay between genes and microbiota in IBD. One recent paper lookedat genetic data and microbiome data from those with IBD and found that they weren’t completely independent: genes and bacteria interacted in complex ways, and both are potentially involved in causing IBDs.
One more factor may be important in the IBD story: what products the microbes make. As microbes go about their metabolic activities in the gut, certain byproducts may have an effect on health outcomes. Some new research, for example, has posited that everyone falls into one of two modes of metabolic activity, or ‘metabotypes’, and almost without exception, those with Crohn’s disease have metabotype two.
Since the microbiota are somehow involved in IBDs, FMT has emerged as a possible way to ‘reboot’ the microbiota and possibly quell symptoms. Some, as described in this article, have already been regularly self-administering FMT with good results. The scientific literature, though, has been slow in coming. A pilot study was recently published in which Chinese doctors treated patients with refractory Crohn’s disease with a single FMT treatment and followed up for a minimum of six months. The immediate effects and high success rate of the treatment should encourage more research studies on the topic.