Gut Microbiota Dysbiosis in Human Obesity: Impact of Bariatric Surgery
Purpose of Review
In this review, we summarize what is currently described in terms of gut microbiota (GM) dysbiosis modification post-bariatric surgery (BS) and their link with BS-induced clinical improvement. We also discuss how the major inter-individual variability in terms of GM changes could impact the clinical improvements seen in patients.
The persisting increase in severe obesity prevalence has led to the subsequent burst in BS number. Indeed, it is to date the best treatment option to induce major and sustainable weight loss and metabolic improvement in these patients. During obesity, the gut microbiota displays distinctive features such as low microbial gene richness and compositional and functional alterations (termed dysbiosis) which have been associated with low-grade inflammation, increased body weight and fat mass, as well as type-2 diabetes. Interestingly, GM changes post-BS is currently being proposed as one the many mechanism explaining BS beneficial clinical outcomes.
BS enables partial rescue of GM dysbiosis observed during obesity. Some of the GM characteristics modified post-BS (composition in terms of bacteria and functions) are linked to BS beneficial outcomes such as weight loss or metabolic improvements. Nevertheless, the changes in GM post-BS display major variability from one patient to the other. As such, further large sample size studies associated with GM transfer studies in animals are still needed to completely decipher the role of GM in the clinical improvements observed post-surgery.
KeywordsBariatric surgery Gut microbiota Metagenomics Richness Obesity Metabolism Akkermansia muciniphila Faecalibacterium prausnitzii Microbial gene richness Type-2 diabetes Roux-en-Y gastric bypass Sleeve gastrectomy Adjustable gastric banding Roseburia intestinalis Proteobacteria Gammaproteobacteria Firmicutes Bacteroidetes BMI HbA1c Remission Illumina
The authors would like to thank Dr. Tim Swartz for the careful English language review of this work.
Funding to support NutriOmics research unit activity on this review topic was obtained from European Union’s Seventh Framework Program (FP7) for research, technological development, and demonstration under grant agreement HEALTH-F4-2012-305312 (Metacardis) and Metagenopolis grant ANR-11-DPBS-0001 and from the Clinical research program (PHRC Microbaria). JAW received grant from Institut Benjamin Delessert and Société Francophone du Diabète (SFD), and KC received an award from the Fondation de France.
JD contributed to the research, discussion of content, and writing of this manuscript; J.A.W contributed to the research, discussion of content, writing, and editing of this manuscript; and K.C. contributed to the discussion of content, writing, and reviewing/editing the manuscript before submission. All authors reviewed the manuscript.
Compliance with Ethical Standards
Conflict of Interest
None of the authors has anything to disclose relevant to this article.
Human and Animal Rights and Informed Consent
All reported studies/experiments with human or animal subjects performed by the authors were performed in accordance with all applicable ethical standards including the Helsinki declaration and its amendments, institutional/national research committee standards, and international/national/institutional guideline.
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
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