title: Gut microbiota after gastric bypass in human obesity: increased richness and associations of bacterial genera with adipose tissue genes.
abstract: BACKGROUND
  Roux-en-Y gastric bypass (RYGB) surgery is one of the most efficient procedures for treating morbid obesity and results in weight-loss and improvements in metabolism and inflammation.
  
  
  OBJECTIVE
  We examined the impact of RYGB on modifications of gut microbiota and its potential associations with changes in gene expression in white adipose tissue (WAT).
  
  
  METHODS
  Gut microbiota were profiled from fecal samples by using pyrosequencing in morbidly obese individuals, explored before (0 mo), 3 mo after, and 6 mo after RYGB. WAT gene expression was studied at 0 and 3 mo. We explored associations between microbial genera and differentially expressed genes in WAT and clinical markers.
  
  
  RESULTS
  The richness of gut microbiota increased after RYGB; 37% of increased bacteria belonged to Proteobacteria. The associations between gut microbiota composition and WAT gene expression increased after RYGB. Fourteen discriminant bacterial genera (7 were dominant and 7 were subdominant) and 202 WAT genes changed after RYGB. Variations in bacterial genera correlated with changes in both clinical phenotype and adipose tissue gene expression. Some genes encode metabolic and inflammatory genes. Almost half of the correlations were independent of the change in calorie intake.
  
  
  CONCLUSIONS
  These results show an increase in gut microbiota richness and in the number of associations between gut microbiota and WAT genes after RYGB in obesity. Variations of gut microbiota were associated with changes in WAT gene expression. These findings stimulate deeper explorations of the mechanisms linking gut microbiome and WAT pathological alterations in human obesity and its changes after weight loss.
authors.affiliation: Institute of Cardiometabolism and Nutrition, Assistance Publique-Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Heart and Metabolism Department, Centre de Recherche Nutrition Humaine, Paris, France 1319 Micalis, Jouy-en-Josas, France.
authors.forename: Ling-Chun
authors.initials: LC
authors.lastname: Kong
authors.forename: Julien
authors.initials: J
authors.lastname: Tap
authors.forename: Judith
authors.initials: J
authors.lastname: Aron-Wisnewsky
authors.forename: Veronique
authors.initials: V
authors.lastname: Pelloux
authors.forename: Arnaud
authors.initials: A
authors.lastname: Basdevant
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Bouillot
authors.forename: Jean-Daniel
authors.initials: JD
authors.lastname: Zucker
authors.forename: Joël
authors.initials: J
authors.lastname: Doré
authors.forename: Karine
authors.initials: K
authors.lastname: Clément
mesh_terms: D052436:Adipose Tissue, White / Q000378:metabolism* / Q000473:pathology; D019295:Computational Biology; D004269:DNA, Bacterial / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000379:methods*; D041981:Gastrointestinal Tract / Q000382:microbiology* / Q000601:surgery; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007249:Inflammation / Q000601:surgery; D054892:Metagenome; D046228:Microarray Analysis; D005810:Multigene Family; D015596:Nutrition Assessment; D009767:Obesity, Morbid / Q000382:microbiology* / Q000601:surgery; D012336:RNA, Ribosomal, 16S / Q000302:isolation & purification; D015431:Weight Loss
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S