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The Gut Microbiome in Adult and Pediatric Functional Gastrointestinal Disorders

  • Andrea Shin
    Affiliations
    Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
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  • Geoffrey A. Preidis
    Affiliations
    Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine and Texas Children’s Hospital, Houston, Texas
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  • Robert Shulman
    Affiliations
    Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine and Texas Children’s Hospital, Houston, Texas
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  • Purna C. Kashyap
    Correspondence
    Reprint requests Address requests for reprints to: Purna C. Kashyap, MBBS, Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905. fax: (507) 266-0350.
    Affiliations
    Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
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Published:August 25, 2018DOI:https://doi.org/10.1016/j.cgh.2018.08.054
      The importance of gut microbiota in gastrointestinal (GI) physiology was well described, but our ability to study gut microbial ecosystems in their entirety was limited by culture-based methods prior to the sequencing revolution. The advent of high-throughput sequencing opened new avenues, allowing us to study gut microbial communities as an aggregate, independent of our ability to culture individual microbes. Early studies focused on association of changes in gut microbiota with different disease states, which was necessary to identify a potential role for microbes and generate novel hypotheses. Over the past few years the field has moved beyond associations to better understand the mechanistic implications of the microbiome in the pathophysiology of complex diseases. This movement also has resulted in a shift in our focus toward therapeutic strategies, which rely on better understanding the mediators of gut microbiota–host cross-talk. It is not surprising the gut microbiome has been implicated in the pathogenesis of functional gastrointestinal disorders given its role in modulating physiological processes such as immune development, GI motility and secretion, epithelial barrier integrity, and brain–gut communication. In this review, we focus on the current state of knowledge and future directions in microbiome research as it pertains to functional gastrointestinal disorders. We summarize the factors that help shape the gut microbiome in human beings. We discuss data from animal models and human studies to highlight existing paradigms regarding the mechanisms underlying microbiota-mediated alterations in physiological processes and their relevance in human interventions. While translation of microbiome science is still in its infancy, the outlook is optimistic and we are advancing in the right direction toward precise mechanism-based microbiota therapies.

      Keywords

      Abbreviations used in this paper:

      CNS (central nervous system), FC (functional constipation), FD (functional dyspepsia), FGID (functional gastrointestinal disorder), 5-HT (5 hydroxytryptamine), FMT (fecal microbiota transplantation), GABA (γ-aminobutyric acid), GF (germ-free), GI (gastrointestinal), IL (interleukin), IBS (irritable bowel syndrome), IBS-C (constipation-predominant irritable bowel syndrome), IBS-D (diarrhea-predominant irritable bowel syndrome), RCT (randomized, placebo-controlled trial), SCFA (short-chain fatty acid), SIBO (small intestinal bacterial overgrowth), TLR (Toll-like receptor)
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