Irritable bowel syndrome, the microbiota and the gut-brain axis

Abstract

Irritable bowel syndrome is a common functional gastrointestinal disorder and it is now evident that irritable bowel syndrome is a multi-factorial complex of changes in microbiota and immunology. The bidirectional neurohumoral integrated communication between the microbiota and the autonomous nervous system is called the gut-brain-axis, which integrates brain and GI functions, such as gut motility, appetite and weight. The gut-brain-axis has a central function in the perpetuation of irritable bowel syndrome and the microbiota plays a critical role. The purpose of this article is to review recent research concerning the epidemiology of irritable bowel syndrome, influence of microbiota, probiota, gut-brainaxis, and possible treatment modalities on irritable bowel syndrome. The integrated actions and communication between the microbiota and the autonomous nervous system are central players in the perpetuation of IBS symptoms. This signaling pathway is called the GutBrain Axis (GBA). The GBA is a bidirectional neurohumoral communication system that integrates brain and GI functions, such as gut motility, appetite and weightand here the microbiota plays a critical role. 2Changes in gastrointestinal or central nervous system physiology may result in an altered habitat, which again may cause changes in the composition of the microbiota.Disruption of the physiologic symbiotic relationship (eubiosis) between the human host and the microbiota is called dysbiosis and is regarded a basic factor for initiating and maintaining IBS in the majority of patients. Current evidence has suggested that the dysbiosis observed in IBS and the resulting immunological response may drive and perpetuate gastrointestinal symptoms of IBS suggesting that IBS is in fact a disorder of the microbiota and the GBA. It is unclear whether the initiating factor is brain abnormalities that drive the gut changes or if changes in the gut alter brain function through vagal and sympathetic pathways.3,4 The purpose of this article is to review recent research concerning the influence of microbiota and gut-brain-axis on IBS. IBSIt is estimated that approximately 10% of the World population and 15% of the population in the Western World suffer from IBS characterized by a mixture of recurrent abdominal pain, bloating, changing stool consistency such as diarrhea (IBS-D), constipation (IBS-C), or interchanging diarrhea and constipation (mixed-type or IBS-M), mucus secretion, and nausea. 5,6 Community-based data indicate that IBS-M is the most prevalent type followed by IBS-D and IBS-C and that switching among subtypes occurs. Bloating is the most prevalent symptom reported by 96% of patients with IBS of whatever subgroup. 7 In addition to abdominal symptoms, poor sleep, headache, CONTACT Hans Raskov raskov@mail.dk Lundevangsvej 23, DK-2900 Hellerup, Denmark. Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/kgmi.

The effect of a multispecies probiotic on microbiota composition in a clinical trial of patients with diarrhea‐predominant irritable bowel syndrome

“…However, data on the differences in the abundance of specific species within these two microbial phyla between IBS and HC are not consistent . In addition, a few recent clinical studies have demonstrated that compositional changes in the intestinal microbiota in IBS are associated with relevant abnormal gastrointestinal and brain–gut axis functions that are often observed in patients with IBS . Taken together, these findings suggest that the gut microbiome plays a role in IBS.…”

Rhizosphere pseudomonads as probiotics improving plant health

“…A population density above a threshold level is required for probiotic efficacy in the human gut and skin. Indeed, disease symptoms in the gut, such as irritable bowel disease, or on the skin, are correlated with a lack of certain microbial colonizers and effective levels of others (Raskov et al, 2016;Winter and Baumler, 2014). The formation of biofilms of probiotics is important for their functioning in the gut.…”

Is irritable bowel syndrome also present in dogs?

“…Examples of the role of microbiota imbalances are reductions in Lactobacillus and Bacteroidetes spp., and increases in Streptococcus spp. (34). An increase in the Firmicutes/ Bacteroides ratio was found in a subgroup of IBS patients (16), and reduced bacterial diversity was observed in other IBS patients (34).…”

“…Both qualitative and quantitative variations of the microbiota (31) may play a role in initiating and perpetuating IBS signs in many patients (34). Examples of the role of microbiota imbalances are reductions in Lactobacillus and Bacteroidetes spp., and increases in Streptococcus spp.…”