Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 14, 2015; 21(14): 4150-4158
Published online Apr 14, 2015. doi: 10.3748/wjg.v21.i14.4150
Changes in the colon microbiota and intestinal cytokine gene expression following minimal intestinal surgery
Susan Lapthorne, Julie E Bines, Fiona Fouhy, Nicole L Dellios, Guineva Wilson, Sarah L Thomas, Michelle Scurr, Catherine Stanton, Paul D Cotter, Prue M Pereira-Fantini
Susan Lapthorne, Nicole L Dellios, Sarah L Thomas, Michelle Scurr, Prue M Pereira-Fantini, Intestinal Failure and Clinical Nutrition group, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria 3052, Australia
Julie E Bines, Intestinal Failure and Clinical Nutrition group, Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia
Julie E Bines, Department of Paediatrics, the University of Melbourne, Parkville, Victoria 3052, Australia
Julie E Bines, Department of Gastroenterology and Clinical Nutrition, Royal Children’s Hospital, Parkville, Victoria 3052, Australia
Fiona Fouhy, Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
Fiona Fouhy, Department of Microbiology, University College Cork, Cork, Ireland
Guineva Wilson, Intestinal Failure and Clinical Nutrition group, Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia
Guineva Wilson, Department of Surgery, Monash Medical Centre, Clayton, Victoria 3052, Australia
Catherine Stanton, Paul D Cotter, Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
Catherine Stanton, Paul D Cotter, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
Author contributions: Lapthorne S, Bines J and Pereira-Fantini P designed the research, performed the research, analyzed the data and wrote the paper; Fouhy F, Dellios NL, Wilson G, Thomas SL and Scurr M, performed the research; Stanton C and Cotter PD contributed new reagents/analytic tools and analyzed the data.
Supported by Victorian Government’s Operational Infrastructure Support program; The PC lab is supported in part by grants from Science Foundation Ireland in the form of a center grant (Alimentary Pharmabiotic Centre; No. SFI/12/RC/2273 and No. 12/RC/2273 and a PI grand to PCR No.11/PI/1137; FF is in receipt of an Irish Research Council EMBARK scholarship and is a Teagasc Walsk Fellow.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Prue M Pereira-Fantini, PhD, Head of Laboratory Research, Intestinal Failure and Clinical Nutrition group, Murdoch Childrens Research Institute, Royal Children’s Hospital, Flemington Road, Parkville Victoria 3052, Australia. prue.pereira@mcri.edu.au
Telephone: +61-3-83416452 Fax: +61-3-93481391
Received: May 28, 2014
Peer-review started: May 28, 2014
First decision: July 21, 2014
Revised: August 6, 2014
Accepted: October 21, 2014
Article in press: October 21, 2014
Published online: April 14, 2015
Processing time: 321 Days and 24 Hours
Abstract

AIM: To investigate the impact of minor abdominal surgery on the caecal microbial population and on markers of gut inflammation.

METHODS: Four week old piglets were randomly allocated to a no-surgery “control” group (n = 6) or a “transection surgery” group (n = 5). During the transection surgery procedure, a conventional midline incision of the lower abdominal wall was made and the small intestine was transected at a site 225 cm proximal to the ileocaecal valve, a 2 cm segment was removed and the intestine was re-anastomosed. Piglets received a polymeric infant formula diet throughout the study period and were sacrificed at two weeks post-surgery. Clinical outcomes including weight, stool consistency and presence of stool fat globules were monitored. High throughput DNA sequencing of colonic content was used to detect surgery-related disturbances in microbial composition at phylum, family and genus level. Diversity and richness estimates were calculated for the control and minor surgery groups. As disturbances in the gut microbial community are linked to inflammation we compared the gene expression of key inflammatory cytokines (TNF, IL1B, IL18, IL12, IL8, IL6 and IL10) in ileum, terminal ileum and colon mucosal extracts obtained from control and abdominal surgery groups at two weeks post-surgery.

RESULTS: Changes in the relative abundance of bacterial species at family and genus level were confined to bacterial members of the Proteobacteria and Bacteroidetes phyla. Family level compositional shifts included a reduction in the relative abundance of Enterobacteriaceae (22.95 ± 5.27 vs 2.07 ± 0.72, P < 0.01), Bacteroidaceae (2.54 ± 0.56 vs 0.86 ± 0.43, P < 0.05) and Rhodospirillaceae (0.40 ± 0.14 vs 0.00 ± 0.00, P < 0.05) following transection surgery. Similarly, at the genus level, changes associated with transection surgery were restricted to members of the Proteobacteria and Bacteroidetes phyla and included decreased relative abundance of Enterobacteriaceae (29.20 ± 6.74 vs 2.88 ± 1.08, P < 0.01), Alistipes (4.82 ± 1.73 vs 0.18 ± 0.13, P < 0.05) and Thalassospira (0.53 ± 0.19 vs 0.00 ± 0.00, P < 0.05). Surgery-associated microbial dysbiosis was accompanied by increased gene expression of markers of inflammation. Within the ileum IL6 expression was decreased (4.46 ± 1.60 vs 0.24 ± 0.06, P < 0.05) following transection surgery. In the terminal ileum, gene expression of TNF was decreased (1.51 ± 0.13 vs 0.80 ± 0.16, P < 0.01) and IL18 (1.21 ± 0.18 vs 2.13 ± 0.24, P < 0.01), IL12 (1.04 ± 0.16 vs 1.82 ± 0.32, P < 0.05) and IL10 (1.04 ± 0.06 vs 1.43 ± 0.09, P < 0.01) gene expression increased following transection surgery. Within the colon, IL12 (0.72 ± 0.13 vs 1.78 ± 0.28, P < 0.01) and IL10 (0.98 ± 0.02 vs 1.95 ± 0.14, P < 0.01) gene expression were increased following transection surgery.

CONCLUSION: This study suggests that minor abdominal surgery in infants, results in long-term alteration of the colonic microbial composition and persistent gastrointestinal inflammation.

Keywords: Surgery; Intestinal; Microbiota; Dysbiosis; Inflammation; Surgery; Bacteria; Infant; Pediatric; Transection

Core tip: Early colonization of the infant gut is increasingly recognized as impacting on health due to the influence of resident microbes on nutritional, immunological and physiological functions. However, medical and surgical interventions required during infancy, including abdominal surgery, have the potential to modify the microbiome. Using 454-pyrosequencing technology we have described microbial dysbiosis within the Proteobacteria and Bacteriodetes phylum and increased gut inflammatory cytokines following transection surgery in a juvenile pig model. This is the first study examining minor surgery-associated changes in the gut microbiome and inflammation and provides new insights into potential long-term consequences of abdominal surgery in infancy.