Gut bless you: The microbiota-gut-brain axis in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common clinical label for medically unexplained gastrointestinal symptoms, recently described as a disturbance of the microbiota-gut-brain axis. Despite decades of research, the pathophysiology of this highly heterogeneous disorder remains elusive. However, a dramatic change in the understanding of the underlying pathophysiological mechanisms surfaced when the importance of gut microbiota protruded the scientific picture. Are we getting any closer to understanding IBS' etiology, or are we drowning in unspecific, conflicting data because we possess limited tools to unravel the cluster of secrets our gut microbiota is concealing? In this comprehensive review we are discussing some of the major important features of IBS and their interaction with gut microbiota, clinical microbiota-altering treatment such as the low FODMAP diet and fecal microbiota transplantation, neuroimaging and methods in microbiota analyses, and current and future challenges with big data analysis in IBS.Supported by the Spanish Ministry of Science and Innovation (MICINN, Spain), No. AGL2017-88801-P (to Sanz Y); the Miguel Server grant from the Spanish "Carlos III" Health Institute (ISCIII), No. CP19/00132 (to Benitez-Paez A); The Norwegian Research Council (Funding Post-doc Position for Bharath Halandur Nagaraja), No. FRIMEDBIO276010; and Helse Vest’s Research Funding, No. HV912243; and ERC H2020-MSCA-IF-2019, No. 895219 (to Haleem N).Peer reviewe