Small Intestinal Permeability Research Articles

Tu1709 Altered Proximal Small-Intestinal Permeability and Bacterial Translocation in Chronic Liver Disease in Relation to Hepatic Fibrosis and Disease Severity

Tu1709 Altered Proximal Small-Intestinal Permeability and Bacterial Translocation in Chronic Liver Disease in Relation to Hepatic Fibrosis and Disease Severity

Role of regenerating gene I in claudin expression and barrier function in the small intestine

We have recently shown that loss of the regenerating gene (Reg) I causes susceptibility to nonsteroidal anti-inflammatory drug-induced gastrointestinal damage. However, the mechanism by which Reg I plays a protective role against this pathophysiological condition is unclear. Here, we investigated whether Reg I plays roles in the induction of tight junction proteins and mucosal barrier function in the small intestine. The small-intestinal permeability was evaluated in Reg I-deficient mice by FITC-dextran and transepithelial electrical resistance (TEER) assay. The effect of REG Iα on TEER, claudins expression, and intracellular signaling was examined using Caco2 cells invitro. Small-intestinal expression of claudins 3 and 4 was investigated in Reg I-deficient mice invivo. REG I deficiency significantly decreased the expression of claudin 3 in the small-intestinal epithelium. When mice were treated with indomethacin, the serum level of FITC-dextran in Reg I knockout mice was significantly higher than that in wild-type (WT) mice. The level of small-intestinal TEER was significantly decreased in Reg I knockout mice compared with WT mice under normal condition. REG Iα stimulation significantly enhanced the level of TEER in Caco2 cells. Treatment with REG Iα enhanced the expression of claudins 3 and 4 and promoted Sp1, Akt, and ERK phosphorylation in Caco2 cells, whereas these effects were attenuated by treatment with anti-REG Iα antibody. Reg I may play a role in the maintenance of mucosal barrier function by inducing tight junction proteins such as claudins 3 and4.

Species differences in the pharmacokinetics of cefadroxil as determined in wildtype and humanized PepT1 mice

PepT1 (SLC15A1) is a high-capacity low-affinity transporter that is important in the absorption of digested di/tripeptides from dietary protein in the small intestine. PepT1 is also crucial for the intestinal uptake and absorption of therapeutic agents such as the β-lactam aminocephalosporins and antiviral prodrugs. Species differences, however, have been observed in PepT1-mediated intestinal absorption and pharmacokinetics, thereby, making it more difficult to predict systemic drug exposure. In the present study, we evaluated the in situ intestinal permeability of the PepT1 substrate cefadroxil in wildtype and humanized PepT1 (huPepT1) mice, and the in vivo absorption and disposition of drug after escalating oral doses. The in situ perfusions indicated that cefadroxil had a twofold higher affinity (i.e., twofold lower Km) for jejunal PepT1 in huPepT1 mice, lower but substantial permeability in all regions of the small intestine, and low but measureable permeability in the colon as compared to wildtype animals. The in vivo experiments indicated almost superimposable pharmacokinetic profiles between the two genotypes after intravenous bolus dosing of cefadroxil. In contrast, after oral dose escalation, the systemic exposure of cefadroxil was reduced in huPepT1 mice as compared to wildtype animals. Moreover, the AUC and Cmax versus dose relationships were nonlinear for huPepT1 but not wildtype mice, and similar to that observed from human subjects. In conclusion, our findings indicate that huPepT1 mice may provide a valuable tool in the drug discovery process by better predicting the oral pharmacokinetic profiles of PepT1 substrates in humans.

P006. Correlation of small intestinal permeability, faecal calprotectin and barrier genes in multiple-affected families with inflammatory bowel disease

P006. Correlation of small intestinal permeability, faecal calprotectin and barrier genes in multiple-affected families with inflammatory bowel disease

Dual-sugar tests of small intestinal permeability are poor predictors of bacterial infections and mortality in cirrhosis: A prospective study.

To prospectively analyze the impact of increased intestinal permeability (IP) on mortality and the occurrence of infections in patients with cirrhosis. IP was quantified using the lactulose/mannitol (L/M) test in 46 hospitalized patients with cirrhosis (25 Child-Pugh A/B, 21 Child-Pugh C) and in 16 healthy controls. Markers of inflammation [LPS-binding protein, Interleukin-6 (IL-6)] and enterocyte death [intestinal fatty-acid binding protein (I-FABP)] were determined in serum using enzyme-linked immunosorbent assays. Patients were followed for one year and assessed for survival, liver transplantation, the necessity of hospitalization and the occurrence of bacterial infections. The primary endpoint of the study was defined as differences in survival between patients with pathological and without pathological lactulose/mannitol test. Thirty-nine (85%) patients with cirrhosis had a pathologically increased IP index (L/M ratio > 0.07) compared to 4 (25%) healthy controls (P < 0.0001). The IP index correlated with the Child-Pugh score (r = 0.484, P = 0.001) and with serum IL-6 (r = 0.342, P = 0.02). Within one year, nineteen (41%) patients developed a total of 33 episodes of hospitalization with bacterial or fungal infections. Although patients who developed spontaneous bacterial peritonitis (SBP) (n = 7) had a higher IP index than patients who did not (0.27 vs 0.14, P = 0.018), the baseline IP index did not predict time to infection, infection-free survival or overall survival, neither when assessed as linear variable, as tertiles, nor dichotomized using an established cut-off. In contrast, model for end-stage liver disease score, Child-Pugh score, the presence of ascites, serum IL-6 and I-FABP were univariate predictors of infection-free survival. Although increased IP is a frequent phenomenon in advanced cirrhosis and may predispose to SBP, it failed to predict infection-free and overall survival in this prospective cohort study.

Intrauterine growth restriction in neonatal piglets affects small intestinal mucosal permeability and mRNA expression of redox‐sensitive genes

Neonates with intrauterine growth restriction (IUGR) show lower efficiency of nutrient utilization compared to normal birth weight (NBW) newborns. This study was conducted using neonatal piglets as a model to test the hypothesis that IUGR affects the intestinal barrier function, intestinal structure, and antioxidant system development during the suckling period. The small intestinal mucosae were obtained from IUGR and NBW littermates in the suckling period (d 0, 3, 8, and 19 postnatal). The epithelial barrier function was assessed by FITC-dextran 4 (FD4) and horseradish peroxidase (HRP) fluxes across the epithelium, histomorphologic measurements, and expression of tight-junction proteins. Redox status represented by the glutathione disulfide/glutathione ratio and malondialdehyde concentrations was determined, whereas mRNA expressions of some redox-sensitive proteins were quantified. Results showed that IUGR piglets exhibited a 2-fold higher intestinal permeability in the proximal small intestine on d 0 (P < 0.05), and this difference between IUGR and NBW piglets was widened to 3 and 4 times for FD4 and HRP, respectively (P < 0.05), on d 3. In accordance, expression of occludin was down-regulated at the transcriptional level in IUGR piglets at d 0 and 19 (P < 0.01). Furthermore, the transcription of heme oxygenase 1, catalase, and thioredoxin reductase genes was down-regulated in IUGR piglets, mainly on postnatal d 0 and 19 (P < 0.01). It appears that IUGR subjects have a lower capacity to mount an antioxidant response in the early postnatal period. Collectively, these results add to our understanding of the mechanisms responsible for intestinal dysfunction in IUGR neonates.

Use of Biomarkers in Irritable Bowel Syndrome: To Predict the Future, Look at the Past.

Use of Biomarkers in Irritable Bowel Syndrome: To Predict the Future, Look at the Past.

Soluble Dextrin Fibers Alter the Intestinal Microbiota and Reduce Proinflammatory Cytokine Secretion in Male IL-10–Deficient Mice1–3

Background: Prebiotic fibers stimulate the growth and activity of the gut microbiota. Interleukin 10–deficient (IL-10−/−) mice develop a colitis that is influenced by the gut microbial composition.Objective: The purpose of this study was to determine the effect of prebiotic fibers on the intestinal microbiota and immune function in IL-10−/− mice.Methods: At 4 wk of age, male IL-10−/− mice (n = 8/group) were randomly assigned to 5 diets: unpurified diet with cellulose (4%; control), corn-derived hydroxypropylated new resistant starch (NRS) (2% NRS + 2% cellulose), soluble fiber dextrin from tapioca (SFD-t) (4%), soluble fiber dextrin from corn (SFD-c) (4%), or soluble corn fiber (4%) for 12 wk. Growth, small intestinal permeability, histologic injury, intestinal cytokine secretion, and microbiota composition by 16S ribosomal RNA pyrosequencing of stool were measured. ANOVA and principal component analysis were applied to assess the fibers' effects.Results: There were no significant differences in mouse growth, intestinal weight, length, or gut permeability over the 12 wk feeding period. Mice fed dextrin-based diets secreted 47–88% less colonic IL-1β, tumor necrosis factor α, and IL-23 (SFD-t diet) and IL-12 heterodimer p70, IL-6, and chemokine ligand 1 (CXCL1) (SFD-c diet) (P < 0.05) than did the control group, whereas NRS-fed mice secreted 55–77% less IL-6 and CXCL1 (P < 0.05). Both SFD-t– and SFD-c–fed mice had a 70–75% lower abundance of Lactobacillaceae than control mice. The SFD-t diet group had a lower enterocyte injury score (P < 0.04) than did control mice, and this was associated with increased abundance of butyrate producers, including Incertae sedis XIV, Lachnospiraceae, and Ruminococcaceae (P < 0.001).Conclusions: These results demonstrate that soluble prebiotic fibers selectively stimulate the growth of a distinctive gut microbiota in IL-10−/− mice. SFD-t induced the growth of butyrate-producing microbes and was effective in reducing proinflammatory cytokine secretion and enterocyte injury in this mouse model of colitis.

The biopharmaceutics of successful controlled release drug product: Segmental-dependent permeability of glipizide vs. metoprolol throughout the intestinal tract

The purpose of this work was to study the challenges and prospects of regional-dependent absorption in a controlled-release scenario, through the oral biopharmaceutics of the sulfonylurea antidiabetic drug glipizide. The BCS solubility class of glipizide was determined, and its physicochemical properties and intestinal permeability were thoroughly investigated, both in-vitro (PAMPA and Caco-2) and in-vivo in rats. Metoprolol was used as the low/high permeability class boundary marker. Glipizide was found to be a low-solubility compound. All intestinal permeability experimental methods revealed similar trend; a mirror image small intestinal permeability with opposite regional/pH-dependency was obtained, a downward trend for glipizide, and an upward trend for metoprolol. Yet the lowest permeability of glipizide (terminal Ileum) was comparable to the lowest permeability of metoprolol (proximal jejunum). At the colon, similar permeability was evident for glipizide and metoprolol, that was higher than metoprolol’s jejunal permeability. We present an analysis that identifies metoprolol’s jejunal permeability as the low/high permeability class benchmark anywhere throughout the intestinal tract; we show that the permeability of both glipizide and metoprolol matches/exceeds this threshold throughout the entire intestinal tract, accounting for their success as controlled-release dosage form. This represents a key biopharmaceutical characteristic for a successful controlled-release dosage form.

Decreased melatonin secretion is associated with increased intestinal permeability and marker of endotoxemia in alcoholics.

Chronic heavy alcohol use is known to cause gut leakiness and alcoholic liver disease (ALD), but only 30% of heavy drinkers develop increased intestinal permeability and ALD. The hypothesis of this study was that disruption of circadian rhythms is a potential risk factor in actively drinking alcoholics for gut leakiness and endotoxemia. We studied 20 subjects with alcohol use disorder (AD) and 17 healthy controls (HC, 6 day workers, 11 night workers). Subjects wore a wrist actiwatch for 7 days and underwent a 24-h dim light phase assessment and urine collection for intestinal permeability. The AD group had significantly less total sleep time and increased fragmentation of sleep (P < 0.05). AD also had significantly lower plasma melatonin levels compared with the HC [mean area under the curve (AUC) 322.78 ± 228.21 vs. 568.75 ± 304.26 pg/ml, P = 0.03]. In the AD group, AUC of melatonin was inversely correlated with small bowel and colonic intestinal permeability (lactulose-to-mannitol ratio, r = -0.39, P = 0.03; urinary sucralose, r = -0.47, P = 0.01). Cosinor analysis of lipopolysaccharide-binding protein (marker of endotoxemia) and lipopolysaccharide every 4 h for 24 h in HC and AD subjects had a midline estimating statistic of rhythm of 5,026.15 ± 409.56 vs. 6,818.02 ± 628.78 ng/ml (P < 0.01) and 0.09 ± 0.03 vs. 0.15 ± 0.19 EU/ml (P < 0.05), respectively. We found plasma melatonin was significantly lower in the AD group, and lower melatonin levels correlated with increased intestinal permeability and a marker of endotoxemia. Our study suggests the suppression of melatonin in AD may promote gut leakiness and endotoxemia.

Sa2031 The Effects of Two Weeks Synbiotic Supplementation on Intestinal Permeability: A Randomized Controlled Trial

Introduction: The intestinal barrier consists of an epithelial, mucus, and immunological barrier. Impaired intestinal barrier function may lead to the infiltration of noxious luminal substances into the intestinal mucosa. This may induce local immune activation or stimulate afferent nerve endings and, subsequently, cause symptoms such as abdominal pain. Pro, preand especially synbiotics are suggested to exert beneficial effects on the intestinal barrier, thereby decreasing intestinal epithelial permeability. The objective of this study was to assess the influence of two weeks synbiotic supplementation on intestinal permeability in vivo in healthy adults. We hypothesized that two weeks synbiotic supplementation will reinforce intestinal barrier function, as reflected by a decrease in intestinal permeability in vivo. Methods: Twenty healthy adults completed a double-blind, placebo-controlled, randomized parallel design study. Groups either received synbiotic (scFOS+Ecologic® 825) or placebo supplements twice daily for two weeks. Intestinal segment specific permeability was assessed non-invasively by oral administration of multiple sugar probes and, subsequently, assessing the excretion of these probes in urine. This test was conducted prior to and after intervention in the absence and, on separate test days, in the presence of an indomethacin challenge. The non-steroidal anti-inflammatory drug indomethacin has been shown to induce reversible damage to the upper gastrointestinal tract, and was applied as a model to study the effects of the supplementation on compromised intestinal barrier function. Results: Gastroduodenal and small intestinal permeability were significantly increased in the indomethacin stressed condition, compared with the unstressed condition, as assessed by urinary sucrose recovery (0.248 [0.206-0.318] vs. 0.363 [0.291-0.637] P<0.05) and urinary lactulose/rhamnose excretion ratio (0.047 [0.039-0.069] vs. 0.118 [0.082-0.165] P<0.001). Indomethacin did not affect colonic permeability as determined by sucralose/erythritol excretion ratio. The synbiotic supplementation did not affect gastroduodenal, small intestinal, and colonic permeability as reflected by urinary sucrose recovery, lactulose/rhamnose excretion ratio and sucralose/erythritol excretion ratio, respectively. These findings were not different among the stressed and unstressed conditions. Conclusion: We confirmed that indomethacin causes damage to the stomach and small intestine. Further, we conclude that two weeks supplementation of scFOS+Ecologic® 825 does not reinforce gastroduodenal, small intestinal or colonic permeability in a healthy gut, nor in a compromised gut.

Sa2032 Salmonella Infection Inhibits Intestinal Biotin Uptake: Cellular/Molecular Mechanisms

non-invasively by oral administration of multiple sugar probes and, subsequently, assessing the excretion of these probes in urine. This test was conducted prior to and after intervention in the absence and, on separate test days, in the presence of an indomethacin challenge. The non-steroidal anti-inflammatory drug indomethacin has been shown to induce reversible damage to the upper gastrointestinal tract, and was applied as a model to study the effects of the supplementation on compromised intestinal barrier function. Results: Gastroduodenal and small intestinal permeability were significantly increased in the indomethacin stressed condition, compared with the unstressed condition, as assessed by urinary sucrose recovery (0.248 [0.206-0.318] vs. 0.363 [0.291-0.637] P<0.05) and urinary lactulose/rhamnose excretion ratio (0.047 [0.039-0.069] vs. 0.118 [0.082-0.165] P<0.001). Indomethacin did not affect colonic permeability as determined by sucralose/erythritol excretion ratio. The synbiotic supplementation did not affect gastroduodenal, small intestinal, and colonic permeability as reflected by urinary sucrose recovery, lactulose/rhamnose excretion ratio and sucralose/ erythritol excretion ratio, respectively. These findings were not different among the stressed and unstressed conditions. Conclusion: We confirmed that indomethacin causes damage to the stomach and small intestine. Further, we conclude that two weeks supplementation of scFOS+Ecologic® 825 does not reinforce gastroduodenal, small intestinal or colonic permeability in a healthy gut, nor in a compromised gut.

P0541 : Small intestinal permeability is elevated in chronic viral hepatitis prior to the development of cirrhosis, and is associated with the degree of fibrosis

P0541 : Small intestinal permeability is elevated in chronic viral hepatitis prior to the development of cirrhosis, and is associated with the degree of fibrosis

Intestinal and gastric permeability in children with eosinophilic esophagitis and reflux esophagitis.

Eosinophilic esophagitis (EoE) is an allergic and immune-mediated entity that leads to a characteristic inflammation of esophageal mucosa. Patients complain of dysphagia and reflux-like symptoms. As many as 80% of patients with EoE may also have a history of atopy, and patients with asthma and eczema have previously been shown to have increased intestinal permeability. This study was designed to assess small intestinal and gastric permeability in patients with EoE and to see whether it differed from healthy individuals and patients with reflux esophagitis (RE). Gastric and small intestinal permeability was measured using sugar probe tests containing lactulose, mannitol, and sucrose. Lactulose-to-mannitol (L/M) ratios in the patient's urine were a measure for intestinal permeability, and total sucrose was a measure for gastric permeability. We analyzed samples from 23 patients with EoE, 20 RE, 14 normal upper endoscopy with gastrointestinal symptoms, and 26 healthy controls. All of the 4 groups had L/M ratios less than the upper limit of normal (<0.025). There was no statistically significant difference in gastric permeability between the 4 groups (L/M P = 0.26, sucrose P = 0.46). Our data suggest that an alteration in gastric and intestinal permeability does not play a role in EoE or RE pathogenesis.

Duodenal morphometry and small bowel permeability in children with portal hypertension.

We prospectively studied children with portal hypertension (PHT) for portal hypertensive duodenopathy (PHTD) and small bowel intestinal permeability (SIP) with the objectives of defining histopathological parameters for PHTD and to find out whether any association existed among structural changes, SIP, and nutritional status. SIP was assessed by using lactulose and mannitol sugar probes in 31 children with PHT (cirrhosis n = 15 and extrahepatic portal venous obstruction n = 16) and 15 healthy children as controls. Morphometric assessment from duodenal biopsies was done in children with PHT. SIP and morphometric parameters were correlated with nutritional status and dietary intake. Among children with PHT, 48% had PHTD defined as presence of villous atrophy (villous to crypt ratio < 2.5:1), dilated capillaries (capillary diameter > 16.8 μm, capillary area > 151 μm, capillary perimeter > 56 μm), and thickened muscularis mucosae (>22.2 μm). Lactulose excretion alone was increased in children with PHT as compared with healthy children (median %: 0.03, 0.02, and 0.01 for cirrhosis, extrahepatic portal venous obstruction, and controls, respectively [P < 0.01]) signifying increased paracellular permeability in PHT. Children with PHT had significantly lower z scores for height, weight, and triceps skin-fold thickness (<-2SD), whereas no differences were found in dietary intake between patients and controls. Increased SIP, nutritional compromise, and PHTD in our patients had no correlation. PHT is often associated with duodenopathy. SIP does occur as a result of increased paracellular permeability. Factors of increased SIP, undernutrition, and PHTD do not have correlation in childhood PHT.

Simultaneous gas-chromatographic urinary measurement of sugar probes to assess intestinal permeability: Use of time course analysis to optimize its use to assess regional gut permeability

BackgroundMeasurement of intestinal permeability is important in several diseases but currently several methods are employed. We sought to: (1) develop a new GC based method to measure urinary mannitol, lactulose and sucralose to assess regional and total gut permeability; (2) analyze the kinetics of these sugars in the urine to determine which ratio is useful to represent intestinal permeability; and (3) determine whether age, gender, race and BMI impact these values. MethodsSubjects drank a cocktail of sucrose, lactulose, mannitol and sucralose and these sugars were measured in the urine at 5, 12 and 24h with gas chromatography. ResultsUrinary mannitol exhibited significantly different kinetics than lactulose and sucralose which were similar to each other and varied little over the 24h. No permeability differences were observed for renal function, age, race, sex, or BMI. ConclusionsOur data do not support the use of the widely used L/M ratio as an accurate estimate of intestinal permeability. Our data support the use of: the sucralose/lactulose (S/M) ratio to measure: small intestine permeability (first 5h); small and large intestine (first 12h), and total gut permeability (24h). This was also found to be true in a Parkinson's disease model.

Increasing small intestinal permeability worsens colitis in the IL-10-/- mouse and prevents the induction of oral tolerance to ovalbumin.

Increased intestinal permeability is found in noninflamed portions of the gut of inflammatory bowel disease patients and in their first-degree relatives, suggesting that it is not a consequence of inflammation. Additionally, increased small intestinal permeability precedes colonic disease in animal models of inflammatory bowel disease. However, it is not known how small intestinal permeability modulates disease in the colon. The aim of this study was to determine if increasing small intestinal permeability modulates colonic inflammation in interleukin (IL)-10 mice and if an increase in permeability is sufficient to prevent oral tolerance to a dietary antigen. IL-10 mice were treated with the zonula occludens toxin pathway agonist AT-1002 for 8 weeks, and colitis severity was measured at 12 weeks of age. Wild-type mice were also treated with AT-1002 and fed ovalbumin (OVA) to determine the local and systemic immune response to this antigen under increased small intestinal permeability conditions. IL-10 mice treated with AT-1002 showed exacerbated colitis at 12 weeks of age. AT-1002 also induced a significant OVA-specific humoral response compared with mice that received OVA alone. In addition, the intestinal production of IL-10 and TGF-β in response to oral OVA was prevented when OVA was given with AT-1002. Increasing small intestinal permeability worsens colitis in IL-10 mice, and it prevents the development of oral tolerance to OVA in wild-type mice. This study suggests that small intestinal permeability is not merely a consequence of inflammation but a condition that leads to two of the main pathological features of inflammatory bowel disease.

Short-term probiotic therapy alleviates small intestinal bacterial overgrowth, but does not improve intestinal permeability in chronic liver disease.

: Although numerous animal studies suggest that probiotic therapy has beneficial effects in various liver diseases, the evidence for beneficial effects in human liver disease is controversial. This study was carried out to investigate the efficacy of probiotic therapy in alleviating small intestinal bacterial overgrowth (SIBO) and permeability in chronic liver disease. Fifty-three patients with chronic liver disease were randomized to either probiotic therapy or placebo. Six bacterial species were used: Bifidobacterium bifidum, Bifidobacterium lactis, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus rhamnosus, and Streptococcus thermophilus. After 4 weeks, changes in the composition of fecal bacteria, SIBO, intestinal permeability, and clinical symptoms were examined. Three of the six probiotic species, B. lactis, L. rhamnosus, and L. acidophilus, increased in the feces of the probiotic therapy group (P<0.001), whereas there was no change in fecal microbiota in the placebo group. SIBO disappeared in many individuals of the probiotic therapy group, but none in the placebo (24 vs. 0%, P<0.05). General gastrointestinal symptoms also improved more in the probiotic group and improvement in intestinal permeability was slightly but not significantly more frequent in the probiotic arm than the placebo arm (50 vs. 31.3%, P=0.248). Numbers of lactobacilli in stool were correlated negatively with intestinal permeability (P for trend<0.05). Liver chemistry did not improve significantly in either group. We conclude that short-term probiotic administration in chronic liver disease is effective in alleviating SIBO and clinical symptoms, but ineffective in improving intestinal permeability and liver function.

Assessment of the capability of a gelling complex made of tara gum and the exopolysaccharides produced by the microorganism Streptococcus thermophilus ST10 to prospectively restore the gut physiological barrier: a pilot study.

Leaky gut, or intestinal permeability, is the phenomenon of the gut wall exhibiting increased absorbency. It is pretty well recognised that an altered or damaged bowel lining or gut wall may result from unbalanced diet, parasites, infection, or medications and that this allows substances such as toxins, microbes, undigested food, or waste to leak through. As a natural consequence, this prompts the body to initiate an immune reaction leading to potentially severe health conditions. Different strategies may be used to improve, at least temporarily, the physiological intestinal barrier. The use of specific beneficial microorganisms, such as lactobacilli and bifidobacteria, has been suggested as an innovative tool to counteract an improper level of intestinal permeability. The association of bacteria with specific gelling agents, such as gums, may represent an improvement since these molecules are able to form hydrophilic gels that distribute uniformly over the inner intestinal surface. This pilot study was undertaken to evaluate intestinal permeability in subjects treated with a gelling complex, an association of tara gum and the microorganism Streptococcus thermophilus ST10 (DSM 25246), which has a well-demonstrated in vitro ability to synthesise and secrete exopolysaccharides (EPSs). Twenty-five healthy subjects were enrolled in this human intervention, double-blind, placebo-controlled, pilot trial (age between 21 and 57 y, mean 37.7±11.2). Subjects were then randomised into 2 groups: group A (13 subjects) was given an active formulation containing 250 mg of tara gum and 1 billion viable cells of S. thermophilus ST10, whereas group B (12 subjects) was given a placebo formulation. All the subjects participating in the study were directed to take 1 dose per day for 30 consecutive days. The presence and concentration of exopolysaccharides (EPSs) in the faeces was determined at time 0 (d0), after 30 days of treatment (d30), and at the end of the 2-week follow-up period (d45). The monosaccharide composition of EPSs was used to quantify the possible contribution of tara gum to the amount of polysaccharides detected in the faecal material. Intestinal permeability was evaluated at the same time by means of the lactitol/mannitol ratio (small intestine permeability) and sucralose concentration (colonic permeability) in urine specimens sampled after specified times. A statistical comparison was made between the concentration of EPSs, the lactulose/mannitol ratio, and the amount of excreted sucralose in the 2 groups at d0, d30, and d45. In the active group, supplementation with S. thermophilus ST10 and tara gum was able to significantly increase the faecal EPSs concentration compared with placebo (from 0.169 mg/g to 0.633 mg/g after 30 d, P<0.001). An interesting decrease in intestinal permeability, both of the small bowel and in the colon, was also recorded. The L/M ratio diminished from 0.021 in the active group to 0.014 and 0.015 after 30 and 45 days, respectively (P=0.045 and P=0.033 compared with placebo). The sucralose concentration decreased from 35.8 mg to 27.9 mg and 29.1 mg (P=0.038 and P=0.026 compared with placebo) at the end of the supplementation period and after the follow-up, respectively. No significant differences were recorded in the placebo after 30 days or at the end of the follow-up. The association of the EPSs produced by S. thermophilus ST10 and tara gum seems capable of significantly improving the intestinal functional barrier in healthy subjects. A wider study in subjects presenting impaired gut permeability would be useful in the future to confirm the positive results from this pilot trial. In any case, our findings are consistent with the parallel increase in exopolysaccharide concentration in the faecal material, thus suggesting the effective ability of the strain used to secrete EPSs in the gut lumen. An innovative approach of this type may be useful in helping to restore the physiological barrier by means of a merely natural and mechanical action.

Rapid small intestinal permeability assay based on riboflavin and lactulose detected by bis-boronic acid appended benzyl viologens

BackgroundAlthough organoboronic acids are efficient high-throughput sugar sensors, they have not been pursued for gut permeability studies. A modification of the lactulose/mannitol assay is described by which small intestinal permeability is assessed at the time of urine collection using a lactulose/riboflavin ratio. MethodsVolunteers ingested 50mg riboflavin and either 5g mannitol or 10g lactulose. Urine was collected for 6hrs. Riboflavin was assayed by autofluorescence. Riboflavin was removed by C18 solid phase extraction. Lactulose and mannitol were then assayed using 1,1’-bis(2-boronobenzyl)-4,4’-bipyridinium (4,4’oBBV) coupled to the fluorophore HPTS. ResultsThe temporal profile over 6hrs for riboflavin paralleled mannitol. Riboflavin recovery in urine was 11.1±1.9 % (mean±SEM, n=7), similar to mannitol. There was selective binding of 4,4’oBBV to lactulose, likely involving cooperativity between the fructose and galactose moieties. Lower limits of detection and quantification were 90 and 364μM. The lactulose assay was insensitive to other permeability probes (e.g., sucrose, sucralose) while tolerating glucose or lactose. This assay can be adapted to automated systems. Stability of 4,4’oBBV exceeds 4years. ConclusionsRiboflavin measured by autofluorescence combined with lactulose measured with 4,4’oBBV represents a useful new chemistry for rapid measurement of intestinal permeability with excellent stability, cost and throughput benefits.