Role of the gut microbiota in inflammatory bowel disease pathogenesis: What have we learnt in the past 10 years?

Abstract

Our understanding of the microbial involvement in inflammatory bowel disease (IBD) pathogenesis has increased exponentially over the past decade. The development of newer molecular tools for the global assessment of the gut microbiome and the identification of nucleotide-binding oligomerization domain-containing protein 2 in 2001 and other susceptibility genes for Crohn's disease in particular has led to better understanding of the aetiopathogenesis of IBD. The microbial studies have elaborated the normal composition of the gut microbiome and its perturbations in the setting of IBD. This altered microbiome or "dysbiosis" is a key player in the protracted course of inflammation in IBD. Numerous genome-wide association studies have identified further genes involved in gastrointestinal innate immunity (including polymorphisms in genes involved in autophagy: ATG16L1 and IGRM), which have helped elucidate the relationship of the local innate immunity with the adjacent luminal bacteria. These developments have also spurred the search for specific pathogens which may have a role in the metamorphosis of the gut microbiome from a symbiotic entity to a putative pathogenic one. Here we review advances in our understanding of microbial involvement in IBD pathogenesis over the past 10 years and offer insight into how this will shape our therapeutic management of the disease in the coming years.

Rifaximin preserves intestinal microbiota balance in patients undergoing allogeneic stem cell transplantation

“…Recently, an increasing number of studies have appeared in support of dysbiosis playing an important role in the pathophysiology of inflammatory processes in the GI tract, 14 with the phylogenetic structure of the intestinal microbiota serving as a surrogate of both the severity of inflammation and therapeutic response in patients with inflammatory bowel disease. 15 In the case of ASCT, recent data strongly indicate a correlation between the loss of a balanced gut microbiota with a concomitant shift to potentially pathogenic bacteria, such as enterococci and the risk of developing acute GI GvHD and long-term clinical outcome.…”

An overview of the bacterial contribution to Crohn disease pathogenesis

“…This approach is of importance in treating and/or preventing chronic inflammatory diseases including IBD (Saez-Lara et al, 2015). Prebiotics were found to alter microbial diversity, enhance mucosal barrier function via production of short-chain fatty acids and mediate direct anti-inflammatory responses (Hold et al, 2014).…”

Protective Effects of Honey and Spirulina Platensis on Acetic Acid-Induced Ulcerative Colitis in Rats

“…In the past, IBD was known as a "Western" disease, while today, its prevalence is rising in Asian countries. The increasing prevalence is attributed to changes in lifestyle, especially dietary habits (2,3). UC is related to an increase in colorectal malignancy that influences patients' quality of life (2).…”