Gut dysbiosis and its treatment in patients with functional dyspepsia

Abstract

Emerging data have focused on the role of impaired permeability of the epithelial barrier, tissue-accumulated eosinophilia, and subtle mucosal inflammation in the duodenum in the pathogenesis of functional dyspepsia (FD). These findings could be mediated by gut microbiota, which have been observed in the large intestine, while the duodenal microbiota may also have a profound effect on various aspects of the host’s physiology. Recent studies have shown that the changes in the composition and function of the duodenal microbiota (dysbiosis) may be associated with several symptoms in patients with FD, especially dysbiosis in the mucosa-­ associated microbiota of the duodenum. In addition to microbiota, dietary food factors may play a role in modifying the duodenal microenvironment by itself as well as through metabolites produced by the interactions between food and microbiota. These data provide growing evidence supporting the crucial role of the duodenal microenvironments in a subgroup of patients with FD. However, their exact role in the complex pathophysiology needs to be further studied, especially focusing on the associations among food factors, microbiota, and host responses. Especially in the clinical field, well-organized studies should be needed to evaluate the potential beneficial effect of dietary interventions and changes in lifestyle.