Intestinal permeability in irritable bowel syndrome patients: effects of NSAIDs.

Intestinal permeability and the effect of NSAIDs on permeability were investigated in 14 irritable bowel syndrome (IBS) patients and 15 healthy subjects. In the study, 24-h urinary recoveries of orally administered polyethylene glycols (PEGs 400, 1500, and 4000) were not significantly different in healthy subjects and IBS patients before or after NSAID ingestion. Lactulose mannitol ratios in healthy subjects and IBS patients were not significantly different. Only time-dependent monitoring of PEG excretion showed that NSAIDs enhanced intestinal permeability for PEG 4000 in healthy subjects (P = 0.050) and for PEGs 400, 1500, and 4000 in IBS patients (P = 0.012, P = 0.041, and P = 0.012, respectively). These results show that intestinal permeability in IBS patients is not different from that in healthy subjects; NSAIDs compromise intestinal permeability in IBS patients to a greater extent than in healthy subjects, which suggests that IBS is associated with an altered response of the intestinal barrier to noxious agents.

Small bowel motility affects glucose absorption in a healthy man.

OBJECTIVE: To investigate the relationship between duodenojejunal motor activity and glucose absorption and to evaluate the effect of modification of duodenojejunal motility on glucose absorption by using the prokinetic drug cisapride. RESEARCH DESIGN AND METHODS: We examined seven healthy males, mean age 22 years, who were treated with cisapride 10 mg t.i.d. and placebo during 3 days in a randomized order, with a 2-week time interval. Duodenojejunal manometry was performed after each treatment on the morning of day 3, using an 18-lumen catheter. A liquid nutrient (3 kcal/min) was administered intraduodenally for 30 min, followed by a bolus of the glucose analog 3-O-methylglucose (3-OMG). Plasma 3-OMG concentrations were measured to assess absorption kinetics. RESULTS: The area under the 3-OMG concentration curve in the first 30 min after infusion was related to the number of antegrade propagated pressure waves (r = 0.49, P < 0.05), but not to the peak concentration, time to peak, and absorption fraction. The mean amplitude of pressure waves was higher during cisapride than placebo (P < 0.05), but the reoccurrence of interdigestive motility, numbers of pressure waves, and propagated pressure waves, as well as 3-OMG absorption characteristics, were not significantly different between the two treatments. During both treatments >60% of antegrade propagated pressure waves were propagated over a very short distance (1.5 cm). CONCLUSIONS: Glucose absorption in the human small intestine is related to short-traveling propagated intestinal contractile activity. Cisapride increases the amplitude of pressure waves, but does not affect the organization of pressure waves or the absorption of 3-OMG.

Systemic inflammation increases intestinal permeability during experimental human endotoxemia.

Although the gut is often considered the motor of sepsis, the relation between systemic inflammation and intestinal permeability in humans is not clear. We analyzed intestinal permeability during experimental endotoxemia in humans. Before and during experimental endotoxemia (Escherichia coli LPS, 2 ng/kg), using polyethylene glycol (PEG) as a permeability marker, intestinal permeability was analyzed in 14 healthy subjects. Enterocyte damage was determined by intestinal fatty acid binding protein. Endotoxemia induced an inflammatory response. Urinary PEGs 1,500 and 4,000 recovery increased from 38.8 +/- 6.3 to 63.1 +/- 12.5 and from 0.58 +/- 0.31 to 3.11 +/- 0.93 mg, respectively (P < 0.05). Intestinal fatty acid binding protein excretion was not affected by endotoxemia. The peak serum IL-10 concentrations correlated with the increase in PEG 1,500 recovery (r = 0.48, P = 0.027). Systemic inflammation results in an increased intestinal permeability. The increase in intestinal permeability is most likely caused by inflammation-induced paracellular permeability, rather than ischemia-mediated enterocyte damage.