Here is an update on the rapidly moving field of inflammatory bowel disease (IBD), from the power of the microbiome to the prediction of IBD and new ways to use established drugs.
Regarding the microbiome, we now understand that, while the healthy microbiome is diverse and able to produce short-chain fatty acids, such as butyrate, the dysbiotic IBD microbiome is less diverse and characterized by expansion of proinflammatory pathobionts (such as Fusobacterium), the proliferation of sulfate-reducing bacteria, and a decrease in anti-inflammatory butyrate production.
There have now been several promising trials of fecal microbial transplant (FMT) for the treatment of ulcerative colitis (UC). The most effective strategies have involved colonic delivery of FMT, pooled donors, and repeated stool enemas to solidify the response. Following FMT, patients’ microbial diversity increases. The hope is that we can use diet as a complement to maintain the diversity and generation of beneficial metabolites, as well as deliver the therapy orally.
Although we have made advances in therapy, we continue to miss opportunities to prevent long-term complications. At Digestive Disease Week,® , a professor of medicine at the Icahn School of Medicine at Mount Sinai, New York, presented data on the PREDICTS study (Aliment Pharacol Ther. 2016 Jun;43:1300-10), in which serum samples collected from military recruits prior to development of IBD was used to identify serologic markers that could predict those who ultimately developed Crohn’s disease but not UC.
The pediatric medical community, meanwhile, has studied an inception cohort of newly diagnosed, untreated children – the RISK cohort ( ) – to define some of the risk factors that predict more aggressive disease. By using biopsy tissue from the time of diagnosis, investigators could predict who would develop stricturing disease versus penetrating disease. Patients who would develop penetrating disease had up-regulation of inflammatory pathways and responded to anti–tumor necrosis factor therapy, while those who developed a stricturing phenotype had increased expression of extracellular matrix pathways and were significantly less likely to respond to anti-TNF therapy ( ). These studies provide a proof of concept that we might someday be able to use for personalized approaches to treating IBD.