Objective Crohn’s disease (CD) is a chronic idiopathic inflammatory intestinal disorder associated with fecal dysbiosis. Fecal Microbial Transplant (FMT) is a potential therapeutic option for individuals with CD based on the hypothesis that changing the fecal dysbiosis could promote less intestinal inflammation. Design Nine patients, ages 12–19 years, with mild to moderate symptoms defined by Pediatric Crohn’s disease activity index (PCDAI of 10–29) were enrolled into a prospective open label study of FMT in CD (FDA IND 14942). Patients received FMT by nasogastric tube with follow up evaluations at 2, 6, and 12 weeks. PCDAI, C-reactive protein (CRP), and fecal calprotectin were evaluated at each study visit. Results All reported adverse events (AE) were graded as mild except for one individual who reported moderate abdominal pain after FMT. All AE were self limiting. Metagenomic evaluation of stool microbiome indicated evidence of FMT engraftment in seven out of nine patients. The mean PCDAI score improved with patients having a baseline of 19.7 ± 7.2, with improvement at 2 weeks to 6.4 ± 6.6, and at 6 weeks to 8.6 ± 4.9. Based upon PCDAI, 7/9 patients were in remission at 2 weeks, and 5/9 patients who did not receive additional medical therapy were in remission at week 6 and 12 weeks. No or modest improvement were seen in the patients who did not engraft or whose microbiome was most similar to their donor. Conclusion This is the first study to demonstrate that FMT for CD may be a possible therapeutic option for Crohn’s disease. Further prospective studies are required to fully assess the safety and efficacy of the FMT in patients with Crohn’s disease.

One hypothesis for the etiology of inflammatory bowel disease is that an altered or pathogenic microbiota causes inflammation in a genetically susceptible individual. Understanding the microbiota's role in the pathogenesis of the disease could lead to new IBD treatments aimed at shifting the bacteria in the gut back to eubiosis. Probiotics have some efficacy in the treatment of ulcerative colitis (UC), but our current repertoire is limited in potency. Fecal microbiota therapy (FMT) is an emerging treatment for several gastrointestinal and metabolic disorders. It has demonstrated efficacy in treating refractory Clostridium difficile infection, and there are case reports of FMT successfully treating UC. Further clinical studies are justified, and could be complemented by mouse models of fecal transplantation, in which variables can be controlled and manipulated.

We discuss the tripartite pathophysiological circuit of inflammatory bowel disease (IBD), involving the intestinal microbiota, barrier function, and immune system. Dysfunction in each of these physiological components (dysbiosis, leaky gut, and inflammation) contributes in a mutually interdependent manner to IBD onset and exacerbation. Genetic and environmental risk factors lead to disruption of gut homeostasis: genetic risks predominantly affect the immune system, environmental risks predominantly affect the microbiota, and both affect barrier function. Multiple genetic and environmental 'hits' are likely necessary to establish and exacerbate disease. Most conventional IBD therapies currently target only one component of the pathophysiological circuit, inflammation; however, many patients with IBD do not respond to immune-modulating therapies. Hope lies in new classes of therapies that target the microbiota and barrier function.

The SCD is utilized by many patients as a primary and adjunct therapy for IBD. Most patients perceive clinical benefit to use of the SCD.