Small things with vast impact: the role of gut microbiota in health and disease

October 24, 2015 By: Christen R. Stensvold

Small things, vast impact: gut microbiota in health & disease

All things microbiota related at UEG Week 2015!

The relevance of manipulating gut microbiota—that is using gut microbiota (e.g. faecal microbiota transplantation [FMT]), components thereof, or diet (including probiotics)—with a view to ameliorating or potentially treating diseases and syndromes is currently subject to intense scrutiny.

The number of conditions that could potentially benefit from gut microbiota manipulation is vast, ranging from autoimmune diseases, such as inflammatory bowel disease (IBD) and multiple sclerosis, to functional bowel diseases (e.g. irritable bowel syndrome [IBS]), antibiotic-induced gut dysbiosis (e.g. recurrent Clostridium difficile infection) and metabolic syndrome. Others include mental health diseases/personality disorders, including anxiety, depression, autism, and schizophrenia.

Through my own research, I have discovered that some intestinal microbes are much more common in healthy individuals than in patients with infectious diarrhoea, functional or inflammatory bowel diseases. Just to be clear, I’m not talking about Akkermansia muciniphila or Faecalibacterium prausnitzii, in fact, I’m not even talking about bacteria! I’m referring to a couple of intestinal protists (Blastocystis sp. and Dientamoeba fragilis) that once were thought by many to be gut pathogens. Well, a lot of recent data not only suggest that they are not gut pathogens, but that they also appear to be much more common than previously anticipated. At our lab, we have developed and are currently validating a gut microbiota profiling tool that enables unprecedented and exhaustive interrogation of ribosomal genes from bacteria, yeasts, moulds, and parasites (protists and helminths) in complex samples, such as stool samples. In other words, we will be able to identify all gut colonising/infecting organisms present in a stool sample to at least genus level, and very often to species level.

Given my background and interests, I was very pleased to learn that UEG Week 2015 has a specific “Gut Microbiota” pathway. I’m going to adhere to it as much as I can! Not only am I interested in being able to pin down every single organism squatting our guts, I also want to know what they do! You’ll definitely find me in Room E2 at the “From omics to better understanding of pathogenesis” session, which is being chaired by my fellow Web Editor, Rui Castro. Here, Loris Lopetuso will present and compare data on gut microbiota composition (16S NGS data) in patients with IBD, IBS, diverticular disease and healthy controls.

If you’re new to research into gut microbiota, you’d do well to attend the talk by Paul O’Toole on “Microbiota: What gastroenterologists should know.” This talk is part of the symposium “Microbiota: Evolving concepts in GI disorders” that takes place in Room F1 on Tuesday 27 October (14:00–15:30). Also in this session, you’ll be able to listen to Patricia Lepage discussing the fundamental issue of causation versus correlation in research into IBD-associated microbiota. Harry Sokol will reveal whether FMT for non-infectious GI diseases is “ready for prime time”, and Gerardo Nardone will deliver a talk with the title, “Microbiota and upper GI diseases: What is the clinical relevance?”

 “Brain–gut interactions in health and disease” is the title of a Round Table Discussion taking place in Room E4 on Tuesday 27 October (14:00–15:30). As Peter Andrey Smith says, referring to the gut-brain axis, “…the mechanisms by which gut microbes and the brain might communicate are unclear, but there are several tantalising leads for researchers to follow.” In a recent News Feature in Nature, he provides some examples as to how differences in gut microbiota may lead to differences in brain development and behaviour. Butyrate, one of the short-chain fatty acids apparently produced by gut bacteria in those of us who are not on the FODMAP diet (for more information, see my previous blog), fortifies the blood–brain barrier by tightening connections between cells, hence influencing the basic physiology of the blood–brain barrier.

I’m also really looking forward to the “Abstracts on Fire: Gut microbiota in lower GI diseases” session, which will be chaired by Antonio Gasbarrini and Herbert Tilg, and takes place at the UEG Hotspot on Wednesday 28 October (8:30–10:30). This free paper session provides us with no less than 12 talks, focusing on topics such as recurrent C. difficile infection and FMT. Among these, we will be spoiled with two talks from Gianluca Ianiro, who is going to try to convince us that surgery is no longer required in patients with C. difficile infection after FMT performed in an academic tertiary care centre.

If you’d like to come and talk to me about gut microbiota in health and disease in general, research communication, or about UEG E-learning, I’ll be at the Young GI Network “Let’s Meet” event on Sunday evening and at the UEG Booth on Monday (13:00–14:00) and Tuesday (15:30–15:45). See you there!

About the author

Dr Christen Rune Stensvold is a Senior Scientist and Public Health Microbiologist with specialty in parasitology. He has a Bachelor degree in Medical Sciences, an MSc in Parasitology, and a PhD in Health Sciences. He has been based at Statens Serum Institut, Copenhagen, since 2004. Since 2006, he has authored/co-authored more than 80 articles in international, peer-reviewed scientific journals. In 2013, he was awarded the Fritz Kauffmann Prize for his contribution to clinical microbiology in Denmark. For many years, he has been pursuing the role of common intestinal micro-eukaryotes in human health and disease. Follow Rune on Twitter @Eukaryotes.



Gianluca, October 24, 2015 18:53
Wonderful article! Beyond bacteria, we are going to know every day something more about the role of fungi and viruses in GI diseases (see IBD), but we don't know so much about protists. May they interact actively with other components of gut microbiota? Before achieving this knowledge, we should know the real composition of the healthy "gut protistome", so many thanks for these exciting data!

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