Chronic constipation is a prevalent, burdensome gastrointestinal disorder whose aetiology and pathophysiology remains poorly understood and is most likely multifactorial. Differences in the composition of the intestinal microbiota have been demonstrated when constipated patients and healthy controls have been compared. Growing evidence indicates that alterations of intestinal microbiota may contribute to constipation and constipation-related symptoms. The intestinal microbiota is a collection of microorganisms that live within the gastrointestinal tract, and perform many important health-promoting functions. The intestinal microbiota aids in the breakdown of food products into absorbable nutrients, stimulates the host immune system, prevents growth of pathogenic bacteria and produces a great variety of biologically important compounds. In this review, we will summarize the current evidence supporting roles of the intestinal microbiota in the pathogenesis and management of chronic constipation. The discussion will shed light on the novel mechanisms of intestinal microbiota and gut function interactions, which is invaluable in ultimately developing new therapeutic tools for the treatment of chronic constipation.

The increased expression of BDNF in colonic mucosa, together with the structural alterations of mucosal innervation, may contribute to the visceral hyperalgesia in IBS.

The intestinal epithelium constitutes a physical and functional barrier between the external environment and the host organism. It is formed by a continuous monolayer of intestinal epithelial cells maintained together by intercellular junctional complex, limiting access of pathogens, toxins and xenobiotics to host tissues. Once this barrier integrity is disrupted, inflammatory disorders and tissue injury are initiated and perpetuated. Beneath the intestinal epithelial cells lies a population of astrocyte-like cells that are known as enteric glia. The morphological characteristics and expression markers of these enteric glia cells were identical to the astrocytes of the central nervous system. In the past few years, enteric glia have been demonstrated to have a trophic and supporting relationship with intestinal epithelial cells. Enteric glia lesions and/or functional defects can be involved in the barrier dysfunction. Besides, factors secreted by enteric glia are important for the regulation of gut barrier function. Moreover, enteric glia have an important impact on epithelial cell transcriptome and induce a shift in epithelial cell phenotype towards increased cell adhesion and cell differentiation. Enteric glia can also preserve epithelial barrier against intestinal bacteria insult. In this review, we will describe the current body of evidence supporting functional roles of enteric glia on intestinal barrier.

The prevalence of IBS is 7.85% in Chinese college and university students according to the Rome III criteria. Low exercise level and anxiety may be the risk factors for IBS.

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