Brief Article
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World J Gastroenterol. May 7, 2014; 20(17): 5000-5007
Published online May 7, 2014. doi: 10.3748/wjg.v20.i17.5000
Caecal pH is a biomarker of excessive colonic fermentation
Adam D Farmer, Sahar D Mohammed, George E Dukes, S Mark Scott, Anthony R Hobson
Adam D Farmer, Sahar D Mohammed, S Mark Scott, Centre for Digestive Diseases, Blizard Institute of Cell and Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AJ, United Kingdom
George E Dukes, GlaxoSmithKline Research and Development Durham County, NC 27709-3398, United States
Anthony R Hobson, Functional Gut Clinic, London W1G 6NB, United Kingdom
Author contributions: Farmer AD wrote the paper and analysed the data; Mohammed SD collected the data; Dukes GE collected the data; Scott SM and Hobson AR pioneered the concept, collected the data and revised the paper for important intellectual content.
Supported by A Grant from the SmartPill Corporation
Correspondence to: Anthony R Hobson, PhD, Consultant Clinical Scientist, Functional Gut Clinic, 22 Upper Wimpole Street, London W1G 6NB, United Kingdom. anthonyhobson@hotmail.com
Telephone: +44-2070-344030 Fax: +44-7850-114966
Received: September 6, 2013
Revised: December 20, 2013
Accepted: January 3, 2014
Published online: May 7, 2014
Processing time: 242 Days and 12.2 Hours
Abstract

AIM: To ascertain whether caecal pH is different in patients with irritable bowel syndrome (IBS), whose primary symptoms are bloating and distension, to healthy controls.

METHODS: Motility and pH data were reviewed from 16 patients with Rome III defined IBS and 16 healthy controls, who had undergone a wireless motility capsule (WMC) study using a standardized protocol. Motility measures were anchored around known anatomical landmarks as identified by compartmental pH changes. Sixty-minute epochs were used to quantify antral, duodenal, ileal, caecal and distal colonic contractility. The maximum and minimum pH was measured either side of the ileo-caecal junction.

RESULTS: No differences were seen in motility parameters, compartmental transit times or maximal ileal pH between the two groups. Caecal pH was significantly lower in patients compared to controls (5.12 ± 0.05 vs 6.16 ± 0.15, P < 0.0001). The ileal:caecal Δchange was greater in patients than controls (-2.63 ± 0.08 vs -1.42 ± 0.11, P < 0.0001). There was a significant correlation between caecal pH and right colonic contractility (r = 0.54, P = 0.002).

CONCLUSION: Patients with bloating and distension have a lower caecal pH compared to controls. The measurement of caecal pH using the WMC provides a quantifiable biomarker of fermentation potentially identifying those patients that may preferentially benefit from antibiotic or dietary interventions.

Keywords: Caecal pH; Caecoparesis; Bloating; Colonic microbiota; Fermentation

Core tip: Colonic bacterial fermentation has been implicated in the pathogenesis of irritable bowel syndrome. Hitherto, the measurement of fermentation in vivo in humans has been invasive and technically challenging. A major by product of colonic bacterial fermentation are short chain fatty acids. These short chain fatty acids act to reduce colonic pH. Herein, we demonstrate that the measurement of caecal ph using the wireless motility capsule provides a quantifiable biomarker of fermentation potentially identifying those patients with irritable bowel syndrome that may preferentially benefit from antibiotic or dietary interventions.