MP34-09 OXALOBACTER FORMIGENES COLONIZATION IN A HYPEROXALURIC RAT MODEL OF GASTRIC BYPASS INCREASES BENEFICIAL GUT BACTERIA AND ACTS AS A KEYSTONE SPECIES

Abstract

You have accessJournal of UrologyStone Disease: Basic Research II1 Apr 2015MP34-09 OXALOBACTER FORMIGENES COLONIZATION IN A HYPEROXALURIC RAT MODEL OF GASTRIC BYPASS INCREASES BENEFICIAL GUT BACTERIA AND ACTS AS A KEYSTONE SPECIES Ryan Chastain-Gross, Ph.D. Gary Wang, M.D., Ph.D. Eric Li, M.S. Marguerite Hatch, andPh.D. Benjamin CanalesM.D., M.P.H. Ryan Chastain-GrossRyan Chastain-Gross More articles by this author , Gary WangGary Wang More articles by this author , Eric LiEric Li More articles by this author , Marguerite HatchMarguerite Hatch More articles by this author , and Benjamin CanalesBenjamin Canales More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1305AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Introduction and Objectives: Patients who undergo the bariatric procedure Roux-en-Y gastric bypass (RYGB) are at increased kidney stone risk due to post-procedural development of enteric hyperoxaluria. Calcium supplementation may decrease stone risk by binding enteric oxalate. Colonization of the GI tract by the probiotic Oxalobacter formigenes (O.f.) reduces urinary oxalate excretion by degrading intraluminal oxalate in addition to promoting enteric oxalate elimination. We hypothesize that these therapies may have additional beneficial effects on the gut microbiome and test this by characterizing the microbiota changes that occur in an RYGB rodent model after administering a high-calcium diet and oral gavage with O.f. METHODS Methods: Diet-induced obese male rats underwent RYGB (n=8) or sham (n=7) surgery with pre- and post-operative urine and stool collections at specified time-points. At 8 weeks post-surgery, all animals were placed on high-calcium diet (2.4%) for 2 weeks and then returned to normal calcium diet (0.6%) for 2 weeks. Rats were then orally gavaged with an actively growing, 24-hour pure culture of a wild, rat-colonizing strain of O.f. (35 mg of wet weight) and followed for 7 weeks. Alterations in intestinal microbiota were analyzed using 16S rRNA Illumina paired-end sequencing followed by UniFrac principal component analysis and linear discriminant analysis coupled with effect sized (LEfSe) measurements. RESULTS Results: Gut microbial community structure was significantly different in RYGB animals compared to sham controls. Manipulation in dietary calcium had minimal effects on the gut microbiome structure. Oral gavage with O.f. induced a modest change in the overall microbial community structure in RYGB animals but not in sham animals. Interestingly, O.f. treatment increased the abundance of Bifidobacterium and Bacteroidales in RYGB animals, and reduced their urinary oxalate levels by 75%. The abundance of these species was not increased in sham animals. CONCLUSIONS Conclusions: The RYGB procedure significantly altered the gut microbiome compared to controls. O.f. colonization but not dietary calcium manipulations in RYGB animals induced a modest change in the composition and structure of the intestinal microbiome. In contrast, the intestinal microbiota of sham animals was stable upon O.f. challenge. These data suggest that O.f. may serve as a keystone species in altering the intestinal microbial community in RYGB animals and warrant further studies in human RYGB patients. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e413-e414 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ryan Chastain-Gross More articles by this author Gary Wang More articles by this author Eric Li More articles by this author Marguerite Hatch More articles by this author Benjamin Canales More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...