October 2017 Newsletter

October 2017 Newsletter

Dear Readers, this newsletter highlights some of the articles in this edition, written by experts in the field, which should arouse your curiosity. Our decision to focus on the scientific area of Microbiotas (with a “M” and a “s”) was motivated by the exponential rise in the number of discoveries and articles illustrating the importance of the relationships we have from birth with our microbiotas (gut, gastric, urologic, pulmonary…).

Individually, we do not all have the same risk of liver diseases. Only a small proportion of individuals, with equivalent alcohol consumption and comparable excess weight, develop hepatitis, cirrhosis or hepatocellular carcinoma.

In this edition, Dr. Anne-Marie Cassard and Prof. Gabriel Perlemuter (Clamart, France) describe how the gut microbiota has emerged as a key cofactor in the appearance of nutritional liver diseases; alcoholic liver disease (ALD) related to alcohol consumption and metabolic steatosis related to excess weight, also known as non-alcoholic fatty liver disease (NAFLD).

Data on the role of gut microbiota in aging processes are limited. In this edition, Prof. Harry Sokol (Paris, France) comments on recent work by Han et al. showing how some bacterial genes may be involved in life expectancy.

The gastrointestinal symptoms reported in children with autism have indicated an influence of microbiota on the pathophysiology of the disease. Prof. Emmanuel Mas (Toulouse, France) describes the promising results obtained by Kang et al. on digestive and behavioural disorders in children with autism following faecal microbiota transplantation.

the literature review of Prof. Dinleyici (Eskisehir, Turkey), the resistance to chemotherapy induced by Fusobacterium nucleatum in colon cancer, the potential value of some probiotics in treating liver diseases, and the fact that the gut microbiota could be used as a diagnostic marker in certain digestive disorders are discussed.

Finally, Prof. Zakharenko (Moscow, Russia) presents his scientific selection from the NeuroGASTRO meeting organized by the European Society of Neurogastroenterology and Motility (24–26 August 2017; Cork, Ireland).

Happy reading!

Gut microbiota influences longevity

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Gut microbiota homeostasis has a major influence on the health and aging of the host. The development of genetically-modified probiotics represents a new promising therapeutic approach to promote healthy aging.

In this study, 3,983 Escherichia coli mutants were screened and 29 bacterial genes involved in host aging were identified. When these genes were deleted, the longevity of the host (the worm, Caenorhabditis elegans) was increased. A dozen of these mutant bacteria also had a protective effect against tumour progression and beta-amyloid accumulation. Mechanistically, five of these mutant bacteria extended longevity by inducing the secretion of a polysaccharide, colanic acid (CA), which regulates mitochondrial dynamics and the unfolded protein response (UPR) in the host. The administration of purified CA polymers was sufficient to increase longevity via ATFS-1, a transcription factor activated by the UPR. In addition, the mitochondrial changes and the effects on longevity induced by CA were conserved between species. Overall, these findings identify molecular targets based on microorganisms and microbial metabolites that increase longevity by acting on the host mitochondria.

Microbiota Transfer Therapy alters gut ecosystem and improves gastro-intestinal and autism symptoms: an open-label study Comments of the original article by K ang et al.

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Autism spectrum disorders (ASD) are complex neurobiological disorders that impair social interactions and communication, and lead to restricted, repetitive, and stereotyped patterns of behaviour, interests, and activities. The causes of these disorders remain poorly understood, however, gut microbiota, comprising 1013 bacteria in the human intestines, have been implicated because children with ASD often suffer gastrointestinal (GI) problems that correlate with ASD severity. Several previous studies have reported abnormal gut bacteria in children with ASD. The gut microbiome-ASD association has been tested in a mouse model of ASD, in which the microbiome was mechanistically linked to abnormal metabolites and behaviour. Similarly, a study of children with ASD found that oral non-absorbable antibiotic treatment alleviated GI and ASD symptoms, albeit temporarily. Here, a small open-label clinical trial evaluated the impact of Microbiota Transfer Therapy (MTT) on gut microbiota composition and GI and ASD symptoms of 18 ASD-diagnosed children.

MTT involved a two-week antibiotic treatment, a bowel cleanse, and then an extended faecal microbiota transplant using a high initial dose followed by daily and lower maintenance doses for 7-8 weeks. The Gastrointestinal Symptom Rating Scale revealed an approximate 80% reduction in GI symptoms at the end of treatment, including significant improvements with regards to symptoms of constipation, diarrhoea, indigestion, and abdominal pain. Improvements persisted for eight weeks after treatment. Similarly, clinical assessments showed that behavioural ASD symptoms decreased significantly and remained at this level for eight weeks after treatment ended. Bacterial and phagedeep sequencing analyses revealed successful partial engraftment of donor microbiota and beneficial changes in the gut environment. Specifically, overall bacterial diversity and the abundance of Bifidobacterium, Prevotella, and Desulfovibrio, among other taxa, increased following MTT, and these changes persisted after treatment was stopped (patients were followed for eight weeks).

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Current understanding of the relationship between intestinal microbiota and the liver

The intimate relationship between the liver and the gastrointestinal tract is well-known. Based on our, albeit incomplete, knowledge of the composition of intestinal microbiota and its role, numerous studies have recently been published on the potential link between gut microbiota composition and liver disease in both animals and humans.

Un nouvel espoir pour les patients atteints de cancer : cibler le microbiote

Mesurer et/ou modifier la composition du microbiote intestinal (principalement Fusobacterium nucleatum) pour améliorer le traitement du cancer colorectal. Le cancer colorectal est l’un des cancers les plus fréquents dans le monde. Les progrès réalisés dans le contrôle de la maladie pourraient être accélérés en augmentant le recours au dépistage à l’âge de 50 ans (ou même plus tôt).

Microbiota evaluation for the diagnosis of gastrointestinal disorders: A marker for differential diagnosis?

Recent studies have shown that gut dysbiosis is associated with chronic inflammatory bowel diseases (CIBD) and Irritable Bowel Syndrome (IBS), as well as other factors such as genetic susceptibility. Evaluation of intestinal microbiota composition, thanks to nextgeneration sequencing, has facilitated analysis and produced reliable taxo-nomic information.

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Report from the conference

NeuroGASTRO 2017

Cork, Irlande

NeuroGASTRO 2017, the congress organised by the European Neurogastroenterology and Motility Society, recently took place in Cork (Ireland), a city steeped in history.

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The Biocodex Microbiota Institute: an international leader in microbiota

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