Gastrointestinal permeability in patients with irritable bowel syndrome assessed using a four probe permeability solution

Abstract

Background: Abnormal gastrointestinal permeability has been linked to irritable bowel syndrome (IBS). The lactulose-to-mannitol ratio is traditionally used to assess small intestine permeability while sucralose and sucrose are used to assess colonic and gastric permeability respectively. We used a single 4-probe test solution to assess permeability throughout the gastrointestinal tract in IBS patients and healthy controls by measuring the recovery of the probes in urine after ingestion using a modified liquid chromatography mass spectrometry protocol.

Methods: Fasting participants (N=59) drank a permeability test solution (100ml: sucralose, sucrose, mannitol, and lactulose). Urine was collected over a 5-h period and kept frozen until analysis. Urinary sugar concentrations were measured using a liquid chromatography/triple quadruple mass spectrometer.

Results: Colonic permeability was significantly lower in IBS patients when compared to healthy controls (p=0.011). Gastric and small intestinal permeability did not significantly differ between the groups.

Conclusions: The study demonstrates the clinical potential of this non-invasive method for assessing alterations in gastrointestinal permeability in patients with IBS.

Figure 1

Standard sugar test solution is used to determine permeability throughout the GI tract. Gastric absorption of sucrose occurs between 0–3 h after solution ingestion. Lactulose is absorbed in the small intestine between 3–5 h and mannitol is used to standardize surface area. Colonic permeability is typically assessed by sucralose excretion ≥ 5 h.

Figure 2

Gastrointestinal permeability of IBS patients vs. healthy controls. (A) Percentage sucrose output (gastric); (B) L/M ratio (small intestine) and (C) Percentage sucralose output (colon). IBS patients exhibited elevated colonic permeability as evidenced by a significant decrease in the recovery of sucralose compared to healthy controls.* p = 0.011.