Roux-en-Y gastric bypass surgery of morbidly obese patients induces swift and persistent changes of the individual gut microbiota

Abstract

BackgroundRoux-en-Y gastric bypass (RYGB) is an effective means to achieve sustained weight loss for morbidly obese individuals. Besides rapid weight reduction, patients achieve major improvements of insulin sensitivity and glucose homeostasis. Dysbiosis of gut microbiota has been associated with obesity and some of its co-morbidities, like type 2 diabetes, and major changes of gut microbial communities have been hypothesized to mediate part of the beneficial metabolic effects observed after RYGB. Here we describe changes in gut microbial taxonomic composition and functional potential following RYGB.MethodsWe recruited 13 morbidly obese patients who underwent RYGB, carefully phenotyped them, and had their gut microbiomes quantified before (n = 13) and 3 months (n = 12) and 12 months (n = 8) after RYGB. Following shotgun metagenomic sequencing of the fecal microbial DNA purified from stools, we characterized the gut microbial composition at species and gene levels followed by functional annotation.ResultsIn parallel with the weight loss and metabolic improvements, gut microbial diversity increased within the first 3 months after RYGB and remained high 1 year later. RYGB led to altered relative abundances of 31 species (P < 0.05, q < 0.15) within the first 3 months, including those of Escherichia coli, Klebsiella pneumoniae, Veillonella spp., Streptococcus spp., Alistipes spp., and Akkermansia muciniphila. Sixteen of these species maintained their altered relative abundances during the following 9 months. Interestingly, Faecalibacterium prausnitzii was the only species that decreased in relative abundance. Fifty-three microbial functional modules increased their relative abundance between baseline and 3 months (P < 0.05, q < 0.17). These functional changes included increased potential (i) to assimilate multiple energy sources using transporters and phosphotransferase systems, (ii) to use aerobic respiration, (iii) to shift from protein degradation to putrefaction, and (iv) to use amino acids and fatty acids as energy sources.ConclusionsWithin 3 months after morbidly obese individuals had undergone RYGB, their gut microbiota featured an increased diversity, an altered composition, an increased potential for oxygen tolerance, and an increased potential for microbial utilization of macro- and micro-nutrients. These changes were maintained for the first year post-RYGB.Trial registrationCurrent controlled trials (ID NCT00810823, NCT01579981, and NCT01993511).Electronic supplementary materialThe online version of this article (doi:10.1186/s13073-016-0312-1) contains supplementary material, which is available to authorized users.

Major microbiota dysbiosis in severe obesity: fate after bariatric surgery

“…MGR increased only progressively and became significant 1 year after both surgeries, concordant with previous reports: (1) 8 RYGB patients showing a non-significantly increased MGR at 1 year10; (2) increased MGR 3 months postsleeve in a cohort similar in size to ours, using shotgun sequencing12; and (3) increased richness 6 months post-RYGB using 16S-pyrosequencing 50. Noteworthy, metformin, which represents the first line of diabetes treatment23 and not a marker of T2D severity, was given at baseline to most of our patients with T2D (8/9).…”

Absence of Role of Dietary Protein Sensing in the Metabolic Benefits of Duodenal-Jejunal Bypass in the Mouse

“…An attractive possibility would be a change in the amount of specific intestinal bacteria conferring metabolic benefits as Prevotella copri 2829 or Akkermansia muciniphila 30. It is noteworthy that Akkermansia muciniphila is increased after gastric bypass in morbidly obese patients3132, and that a protein from its membrane is beneficial for glucose control by itself33.…”

Impact of Roux-En-Y Gastric Bypass Surgery on Neurohormonal and Gastrointestinal Physiology: Insights for Future Weight Loss Efforts

“…Similar gut microbial changes were seen after non-surgical weight loss [112,118]. Unlike in non-surgical weight loss, there was an increased abundance of Proteobacteria, specifically Escherichia coli, after RYGB [115][116][117][119][120][121][122][123]. Enterobacteriaceae and Pasteurellaceae were also associated with weight loss after RYGB [122,123].…”