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Purpose: Exertional heat stress adversely distrupts (GI) barrier integrity and, through subsequent microbial translocation (MT), negativly impacts health. Despite widespread application, the temporal reliability of popular GI barrier integity and MT biomarkers is poorly characterised., Method: Fourteen males completed two 80-min exertional heat stress tests (EHST) separated by 7-14 days. Venous blood was drawn pre, immediately- and 1-hr post both EHSTs. GI barrier integrity was assessed using the serum Dual-Sugar Absorption Test (DSAT), Intestinal Fatty-Acid-Binding Protein (I-FABP) and Claudin-3 (CLDN-3). MT was assessed using plasma Lipopolysaccharide Binding Protein (LBP), total 16S bacterial DNA and Bacteroides DNA., Results: No GI barrier integrity or MT biomarker, except absolute Bacteroides DNA, displayed systematic trial order bias (p ≥ .05). I-FABP (trial 1 = Δ 0.834 ± 0.445 ng ml -1 ; trial 2 = Δ 0.776 ± 0.489 ng ml -1 ) and CLDN-3 (trial 1 = Δ 0.317 ± 0.586 ng ml -1 ; trial 2 = Δ 0.371 ± 0.508 ng ml -1 ) were increased post-EHST (p ≤ .01). All MT biomarkers were unchanged post-EHST. Coefficient of variation and typical error of measurement post-EHST were: 11.5% and 0.004 (ratio) for the DSAT 90-min postprobe ingestion; 12.2% and 0.004 (ratio) at 150-min postprobe ingestion; 12.1% and 0.376 ng ml -1 for I-FABP; 4.9% and 0.342 ng ml -1 for CLDN-3; 9.2% and 0.420 µg ml -1 for LBP; 9.5% and 0.15 pg µl -1 for total 16S DNA; and 54.7% and 0.032 for Bacteroides/total 16S DNA ratio., Conclusion: Each GI barrier integrity and MT translocation biomarker, except Bacteroides/total 16S ratio, had acceptable reliability at rest and postexertional heat stress., (© 2020 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

Fasting of up to 24 hr has been shown to increase intestinal permeability (IP) in chickens. The aim of this study was to determine whether fasting duration of 4.5 and 9 hr increased IP and whether l-glutamine (a non-essential amino acid) supplementation before fasting provided some protection of barrier function as shown in other species. Ross 308 male broilers (n = 96) were fed either a control diet or the same diet supplemented with 1% glutamine from d0 to d38 post-hatch. On d37, the birds were assigned to single-bird metabolism cages and were fasted for either 0, 4.5, 9 or 19.5 hr. This study design was 2 × 4 factorial with two levels of glutamine and four levels of fasting. Birds in the 0-hr fasting group had free access to feed. All birds had ad libitum access to water. To measure IP on day 38, following their respective fasting periods, birds were administered two separate oral gavages of fluorescein isothiocyanate dextran (FITC-d) followed by lactulose, mannitol and rhamnose (LMR) sugars, 60 min apart. Whole blood was collected from the jugular vein 90 min post-LMR sugar gavage. FITC-d and L/M/R ratios were measured by spectrophotometry and high-performance ionic chromatography respectively. Lipopolysaccharide (LPS) endotoxins in plasma of the birds fed the control diet were also measured using chicken-specific LPS antibody ELISA. Serum FITC-d and plasma L/M and L/R ratios for 4.5, 9 and 19.5 hr were significantly (p < .05) higher compared to the non-fasting group. However, IP was not different in the glutamine-supplemented group (p > .05) compared to the control group. LPS concentrations measured by the ELISA were below the detectable range. We conclude that fasting periods of 4.5 and 9 hr increased IP compared to non-fasted birds and dietary glutamine supplementation did not ameliorate changes in IP., (© 2017 Blackwell Verlag GmbH.)

Increased intestinal permeability (IP) can lead to compromised health in chickens. As there is limited literature on in vivo biomarkers to assess increased IP in chickens, the objective of this study was to identify a reliable biomarker of IP using DSS ingestion and fasting models. Male Ross chickens (n = 48) were reared until day 14 on the floor pen in an animal care facility, randomized into the following groups: control, DSS and fasting (each with n = 16), and then placed in metabolism cages. DSS was administered in drinking water at 0.75% from days 16 to 21, while controls and fasted groups received water. All birds had free access to feed and water except the birds in the fasting group that were denied feed for 19.5 h on day 20. On day 21, all chickens were given two separate oral gavages comprising fluorescein isothiocyanate dextran (FITC-d, 2.2 mg in 1 ml/bird) at time zero and lactulose, mannitol and rhamnose (LMR) sugars (0.25 g L, 0.05 g M and 0.05 g R in 2 ml/bird) at 60 min. Whole blood was collected from the brachial vein in a syringe 90 min post-LMR sugar gavage. Serum FITC-d and plasma LMR sugar concentrations were measured by spectrophotometry and high-performance ion chromatography respectively. Plasma concentrations of intestinal fatty acid binding protein, diamine oxidase, tight junction protein (TJP), d-lactate and faecal α-antitrypsin inhibitor concentration were also analysed by ELISA. FITC-d increased significantly (p < 0.05) after fasting compared with control. L/M and L/R ratios for fasting and L/M ratio for DSS increased compared with control chickens (p < 0.05). TJP in plasma was significantly increased due to fasting but not DSS treatment, compared with controls. Other tests did not indicate changes in IP (p > 0.05). We concluded that FITC-d and LMR sugar tests can be used in chickens to assess changes in IP., (Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.)

Increased intestinal permeability and translocation of gut bacteria trigger various polyaetiological diseases associated with chronic inflammation and underlie a variety of poorly treatable pathologies. Previous studies have established a primary role of the microbiota composition and intestinal permeability in such pathologies. Using a rat model, we examined the effects of exposure to a bacteriophage cocktail on intestinal permeability and relative abundance of taxonomic units in the gut bacterial community. There was an increase in markers of impaired gut permeability, such as the lactulose/mannitol ratio, plasma endotoxin concentrations, and serum levels of inflammation-related cytokines, following the bacteriophage challenge. We observed significant differences in the alpha diversity of faecal bacterial species and found that richness and diversity index values increased following the bacteriophage challenge. There was a reduction in the abundance of Blautia, Catenibacterium, Lactobacillus, and Faecalibacterium species and an increase in Butyrivibrio, Oscillospira and Ruminococcus after bacteriophage administration. These findings provide novel insights into the role of bacteriophages as potentially pathogenic for mammals and their possible implication in the development of diseases associated with increased intestinal permeability.

Increased intestinal permeability (IP) can lead to compromised health. Limited in vivo IP research has been conducted in chickens. The objectives of the current study were to develop a model of increased IP utilizing lipopolysaccharide (LPS Escherichia coli O55:B5) and to evaluate IP changes using the lactulose, mannitol and rhamnose (LMR) sugar permeability test. In addition, fluorescein isothiocyanate dextran (FITC-d), d-lactate, zonula occludens (ZO-1) and diamine oxidase (DAO) permeability tests were employed. Male Ross chickens were reared until day 14 on the floor in an animal care facility and then transferred to individual cages in three separate experiments. In each of experiments 1 and 2, 36 chicks were randomly allocated to receive either saline (control) or LPS (n=18/group). Lactulose, mannitol and rhamnose sugar concentration in blood was measured at 0, 30, 60, 90, 120 and 180 min in experiment 1, at 60, 90 and 120 min in experiment 2 and at 90 min in experiment 3 (n=16/group). Lipopolysaccharide was injected intraperitoneally at doses of 0.5, 1 and 1 mg/kg BW in experiments 1, 2 and 3, respectively, on days 16, 18 and 20, whereas control received sterile saline. On day 21, only birds in experiments 1 and 2 were fasted for 19.5 h. Chicks were orally gavaged with the LMR sugars (0.25 gL, 0.05 gM, 0.05 gR/bird) followed by blood collection (from the brachial vein) as per time point for each experiment. Only in experiment 3, were birds given an additional oral gavage of FITC-d (2.2 mg/ml per bird) 60 min after the first gavage. Plasma d-lactate, ZO-1 and DAO concentrations were also determined by ELISA in experiment 3 (n=10). Administration of LPS did not affect IP as measured by the LMR sugar test compared with control. This was also confirmed by FITC-d and DAO levels in experiment 3 (P>0.05). The plasma levels of d-lactate were decreased (P<0.05). Plasma levels of ZO-1 were increased in the third experiment only and did not change in the first two experiments. Lipopolysaccharide at doses of 0.5 and 1 mg/kg did not increase IP in this model system. In conclusion, the LMR sugar can be detected in blood 90 min after the oral gavage. Further studies are needed for the applicability of LMR sugars tests.

Controlled studies on the effect of exercise on intestinal uptake of protein are scarce and underlying mechanisms largely unclear. We studied the uptake of the major allergen Ara h 6 following peanut consumption in an exercise model and compared this with changes in markers of intestinal permeability and integrity. Ten overnight-fasted healthy non-allergic men ( n = 4) and women ( n = 6) (23 ± 4 years) ingested 100 g of peanuts together with a lactulose/rhamnose (L/R) solution, followed by rest or by 60 min cycling at 70% of their maximal workload. Significantly higher, though variable, levels of Ara h 6 in serum were found during exercise compared to rest (Peak p = 0.03; area under the curve p = 0.006), with individual fold changes ranging from no increase to an increase of over 150-fold in the uptake of Ara h 6. Similarly, uptake of lactulose (2-18 fold change, p = 0.0009) and L/R ratios (0.4-7.9 fold change, p = 0.04) were significantly increased which indicates an increase in intestinal permeability. Intestinal permeability and uptake of Ara h 6 were strongly correlated ( r = 0.77, p < 0.0001 for lactulose and Ara h 6). Endurance exercise after consumption may lead to increased paracellular intestinal uptake of food proteins., Competing Interests: The authors declare no conflict of interest.

Background: Lactulose/mannitol (L:M) test has been used as a non-invasive marker of intestinal mucosal -integrity and -permeability (enteropathy). We investigated the association of enteropathy with anthropometrics, micronutrient- status, and morbidity in children., Methods: The urine and blood samples were collected from 925 children aged 6-24 months residing in Mirpur slum of Dhaka, Bangladesh during November 2009 to April 2013. L:M test and micronutrient status were assessed in the laboratory of International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b) following standard procedure., Results: Mean±SD age of the children was 13.2±5.2 months and 47.8% were female. Urinary- lactulose recovery was 0.264±0.236, mannitol recovery was 3.423±3.952, and L:M was 0.109±0.158. An overall negative correlation (Spearman's-rho) of L:M was found with age (rs = -0.087; p = 0.004), weight-for-age (rs = -0.077; p = 0.010), weight-for-length (rs = -0.060; p = 0.034), mid-upper-arm-circumference (rs = -0.098; p = 0.001) and plasma-retinol (rs = -0.105; p = 0.002); and a positive correlation with plasma α-1-acid glycoprotein (rs = 0.066; p = 0.027). However, most of the correlations were not very strong. Approximately 44% of children had enteropathy as reflected by L:M of ≥0.09. Logistic regression analysis revealed that younger age (infancy) (adjusted odds ratio (AOR) = 1.35; p = 0.027), diarrhea (AOR = 4.00; p = 0.039) or fever (AOR = 2.18; p = 0.003) within previous three days of L:M test were the risk factors of enteropathy (L:M of ≥0.09)., Conclusions: Enteropathy (high L:M) is associated with younger age, undernutrition, low vitamin A and iron status, and infection particularly diarrhea and fever., Competing Interests: The authors have declared that no competing interests exist.

Background: A prospective, randomized, controlled study was performed to evaluate the effects of perioperative alanyl-glutamine-supplemented parenteral nutrition (PN) support on the immunologic function, intestinal permeability, and nutrition status of surgical patients with chronic radiation enteritis (CRE)-induced intestinal obstruction., Methods: Patients who received 0.4 g/kg/d alanyl-glutamine and isonitrogenous PN were assigned to an alanyl-glutamine-supplemented PN (Gln-PN) group and a control group, respectively. Serum levels of alanine aminotransferase and glutamine, body fat mass (FM), immunologic function, and intestinal permeability were measured before and after surgery., Results: Serum glutamine levels of the Gln-PN group significantly exceeded that of the control group (P < .001; Gln-PN, baseline 460.7 ± 42.5 vs 523.3 ± 48.6 µmol/L on postoperative day 14 [POD14], P < .001; control, baseline 451.9 ± 44.0 vs 453.8 ± 42.3 µmol/L on POD14, P = .708). Lactulose/mannitol ratios of both groups decreased over time (Gln-PN, baseline 0.129 ± 0.0403 vs 0.024 ± 0.0107 on POD1 4; control, baseline 0.125 ± 0.0378 vs 0.044 ± 0.0126 on POD14, P < .001 in both groups). CD4/CD8-positive T-lymphocyte ratios significantly rose in both groups, with significant intergroup difference (P < .001; Gln-PN, baseline 1.36 ± 0.32 vs 1.82 ± 0.30 on POD14, P < .001; control, baseline 1.37 ± 0.25 vs 1.63 ± 0.31 on POD14, P < .001). In the Gln-PN group, FM increased from 3.68 ± 1.68 kg at baseline to 5.22 ± 1.42 kg on POD14 (P < .001). FM of control group increased from 3.84 ± 1.57 kg at baseline to 5.40 ± 1.54 kg on POD14 (P < .001). However, there were no significant intergroup differences (P = .614)., Conclusion: Gln-PN significantly boosted the immune state and decreased the intestinal permeability of CRE patients. However, Gln-PN was not superior to standard PN in improving the nutrition state and intestinal motility of surgical patients with CRE-induced intestinal obstruction., (© 2015 American Society for Parenteral and Enteral Nutrition.)

Background: Lactulose is commonly used for constipation and hepatic encephalopathy. Its adverse effects of dehydration and serum electrolyte imbalances are widely known., Objective: This study aimed to describe a case series of 3 patients receiving lactulose who developed lithium toxicity., Methods: The authors described a case series of 3 patients admitted to a large county psychiatric hospital who developed lithium toxicity while taking lactulose for constipation or hyperammonemia., Results: In all 3 cases of lithium toxicity, the patients were prescribed with lithium for acute mania and lactulose for constipation or hyperammonemia. One case required the patient to be transferred to a local emergency department for further treatment., Conclusions: This case series shows the interaction between lithium and lactulose. It is postulated that lactulose's effects of volume depletion can lead to poor renal excretion of lithium.

The aim of the study was to assess the small intestine permeability by using lactulose as a sugar probe and blood metabolites in sheep after a challenge with repeated indomethacin injections. According to a changeover design, 7 adult sheep (4 males and 3 females) were subjected to 4 intramuscular injections (every 12 h) of saline [control (CRT); 7 animals] or indomethacin (INDO; 7 animals). Two hours after the last injection, 30 g of lactulose were administered orally to both CTR and INDO. Blood samples were collected daily for the analysis of the metabolic profile and 5 samples were collected at 2-h intervals following lactulose ingestion to monitor changes in blood levels of lactulose as an index of intestinal permeability. The INDO challenge induced clinical symptoms such as lack of appetite, dullness, weakness, depression, and diarrhea with traces of blood in the feces. In INDO group, haptoglobin and ceruloplasmin increased (P < 0.01) after INDO challenge whereas a decrease (P < 0.05) of negative acute phase reactants (e.g., cholesterol, albumin, and paraoxonase) was observed. Reactive oxygen metabolites increased (P < 0.01) from 60 to 204 h after the INDO challenge start, with a decrease of vitamin E concentration from 12 (P < 0.01) to 132 h (P < 0.05). Blood lactulose concentrations were increased (P < 0.05) in INDO animals and the highest mean values (17.67 µg/mL in INDO vs. 0.17 µg/mL in CRT; P < 0.01) were observed 6 h after oral dosage of lactulose. These changes indicate that the INDO challenge led to severe inflammatory responses with oxidative stress by enhancing small intestinal permeability in sheep that allowed lactulose to enter in blood. The results of this experiment demonstrate that lactulose can be used as a probe to assess gastrointestinal permeability in adult ruminants to test the consequences of stressing conditions on animal welfare. For this purpose, the most suitable time for blood sampling is between 2 and 8 h after the oral dosage of lactulose.

Objective: Coeliac disease is defined by gluten responsiveness, yet there are few data on gluten challenge (GC) in adults on a gluten-free diet. Lack of data regarding the kinetics of responses to gluten is a limitation in clinical practice and research when GC is performed., Design: 20 adults with biopsy-proven coeliac disease participated. The study included two run-in visits followed by a 14-day GC at a randomly assigned dose of 3 or 7.5 g of gluten/day. Study visits occurred 3, 7, 14 and 28 days after starting GC. Duodenal biopsy was performed during the run-in and at days 3 and 14 of GC. Villous height to crypt depth ratio (Vh:Cd) and intraepithelial lymphocyte (IEL) count/100 enterocytes were measured by two pathologists. Antibodies to tissue transglutaminase and deamidated gliadin peptides, lactulose to mannitol ratio (LAMA) and symptoms were assessed at each visit., Results: Significant reduction in Vh:Cd (2.2-1.1, p<0.001) and increase in IELs (32.6-51.8, p<0.001) were seen from baseline to day 14. Antibody titres increased slightly from baseline to day 14 of GC but markedly by day 28. LAMA did not change significantly. Gastrointestinal symptoms increased significantly by day 3 and returned to baseline by day 28. No differences were seen between the two gluten doses., Conclusions: 14 day GC at ≥ 3 g of gluten/day induces histological and serological changes in the majority of adults with coeliac disease. These data permit accurate design of clinical trials and indicate that many individuals will meet coeliac diagnostic criteria after a 2-week GC.

Background & Aims: Increased gastrointestinal (GI) permeability is an important hallmark of many conditions, potentially leading to antigen exposure and sepsis. Current permeability tests are hampered by analytical limitations. This study aims to compare the accuracy of our multi-sugar (MS) and the classical dual sugar (DS) test for detection of increased GI permeability., Methods: Ten volunteers received permeability analysis using MS (1 g sucrose, lactulose, sucralose, erythritol, 0.5 g rhamnose in water) or DS (5 g lactulose, 0.5 g rhamnose), after indomethacin or placebo. Blood and urine were analyzed by isocratic LC-MS., Results: MS testing revealed significantly elevated urinary lactulose/rhamnose (L/R) ratios after indomethacin, due to enhanced lactulose excretion (P < .01) and unaltered rhamnose excretion. The DS test showed increased L/R ratios, due to increased lactulose excretion and decreased rhamnose excretion (both P < .05). After indomethacin, plasma L/R increased in both assays (P < .05 and P < .01). Urinary and plasma L/R ratios correlated significantly. Indomethacin increased sucrose excretion and 0-1 h sucrose/rhamnose. Colon permeability was unchanged., Conclusions: Sensitive permeability analysis is feasible in plasma and urine using MS or DS test. In contrast to the DS test, monosaccharide excretion is not decreased by the MS test. In short, the MS test provides accurate, site-specific information on gastroduodenal, small, and large intestinal permeability. Registered at US National Library of Medicine (http://www.clinicaltrials.gov, NCT00943345)., (Copyright © 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

The present paper demonstrates that electrochemical detection (ECD) coupled to ion chromatography and electrospray ionization tandem mass spectrometry (IC-ECD-ESI/MS/MS) can be used to rapidly estimate some indications of the health status of organisms. The lactulose to mannitol ratio (L/M) is used as a non-invasive assay to investigate small intestinal absorption pathways and mucosal integrity. In the present study, an evaluation of the negative effects of nonsteroidal anti-inflammatory drug meloxicam perorally administrated to a group of dogs was carried out by determining the lactulose/mannitol index using the IC-ECD-ESI/MS/MS hyphenated technique. According to the results of the study, meloxicam altered gastrointestinal permeability. Coenzyme Q(10) (CoQ(10)) was tested to determine if it could prevent meloxicam induced gastrointestinal damage and it was found that CoQ(10) could be an effective preventive treatment. Furthermore, plasma glucose concentration level was determined to be an indirect indicator of the oxidative state in the blood. To find out the beneficial effects of a double antioxidant combination (α-lipoic acid (ALA) and CoQ(10)) on the total glucose level in chickens, ALA and CoQ(10) were provided as food additives in factory farm raised chicken. The results of the pilot study indicate that the glucose level in the plasma of chickens group fed with CoQ(10) and ALA was significantly decreased compared to the control group. Ion chromatography (IC) utilizing pulsed amperometric detection (PAD) was compared to ion chromatography coupled with tandem mass spectrometry (MS/MS) as an analytical tool for monitoring the carbohydrate level in biological fluids. In electrochemical detection, the newly developed two-pulse waveform successfully withstands matrix effects in biological samples. Continuous on-line desalting of the high salt concentrations used as the eluent for carbohydrate separation from the anion-exchange column allows coupling of IC and MS techniques. A make-up solution (0.5mM LiCl) was delivered prior to MS detection for efficient ionization of eluted carbohydrates. Method validation showed that both used techniques are practically comparable and some advantages of each are presented., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Objective: Environmental enteropathy syndrome may compromise growth and predispose to infectious diseases in children in the developing world, including Australian Aboriginal children from remote communities of the Northern Territory. In this study, we described the use of a biomarker (13)C-sucrose breath test (SBT) to measure enterocyte sucrase activity as a marker of small intestinal villus integrity and function., Methods: This was a hospital-based prospective case-control study of Aboriginal and non-Aboriginal children with and without acute diarrheal disease. Using the SBT, we compared 36 Aboriginal case subjects admitted to a hospital (18 diarrheal and 18 nondiarrheal disease), with 7 healthy non-Aboriginal control subjects. Intestinal permeability using the lactulose/rhamnose (L/R) ratio on a timed 90-minute blood test was performed simultaneously with the SBT. The SBT results are expressed as a cumulative percentage of the dose recovered at 90 minutes., Results: Aboriginal children with acute diarrheal disease have a significantly decreased absorptive capacity, as determined by the SBT, with a mean of 1.9% compared with either Aboriginal children without diarrhea (4.1%) or non-Aboriginal (6.1%) control subjects. The mean L/R ratio in the diarrhea group was 31.8 compared with 11.4 in Aboriginal children without diarrhea. There was a significant inverse correlation between the SBT and the L/R ratio., Conclusions: The SBT was able to discriminate among Aboriginal children with diarrhea, asymptomatic Aboriginal children with an underlying environmental enteropathy, and healthy non-Aboriginal controls. This test provides a noninvasive, easy-to-use, integrated marker of the absorptive capacity and integrity of the small intestine and could be a valuable tool in evaluating the efficacy of interventions aimed at improving gut health.

Aim: To evaluate the effects of combined treatment of glutamine (Gln) and recombinant human growth hormone(rhGH) on intestinal barrier function following portal hypertension surgery., Methods: This study was designed as a prospective, randomized and controlled clinical trial. Forty two patients after portal hypertension surgery were randomly assigned into 2 groups: control group (n = 20) and supplemental group (adding Gln and rhGH, n = 22). Every patient received isocaloric and isonitrogenous standard total parenteral nutrition (TPN) starting 3 d after surgery for 7 d. Blood samples were obtained before surgery and at the 3rd and 10th day postoperatively. Host immunity was evaluated by measuring levels of CD4, CD8, CD4/CD8, IgG, IgM and IgA, and the inflammatory responses were determined by assessing IL-2, TNF-alpha and C-reactive protein (CRP) levels. Intestinal permeability and integrity was evaluated by L/M test and histological examination, respectively., Results: On postoperative d 10, CD4, CD4/CD8, IgG and IL-2 levels in supplemental group were significantly higher than those in control group (33.7 +/- 5.5 vs 31.0 +/- 5.4, P < 0.05, (1.17 +/- 0.32 vs 1.05 +/- 0.15, P < 0.05, 13.94 +/- 1.09 vs 12.33 +/- 1.33, P < 0.05, and 368.12 +/- 59.25 vs 318.12 +/- 45.65, P < 0.05, respectively), whereas the increase in serum TNF-alpha concentration was significantly reduced (41.02 +/- 27.56 vs 160.09 +/- 35.17, P < 0.05). The increase in L/M ratio was significantly lower in the supplemental group than in the control group (0.0166 +/- 0.0017 vs 0.0339 +/- 0.0028, P < 0.05). Moreover, mucosal integrity in the supplemental group was better than in the control group., Conclusion: Postoperative administration of TPN supplemented with Gln and rhGH in patients after portal hypertension surgery improves immune function, modulates inflammatory response, prevents the intestinal mucous membrane from atrophy and preserves intestinal integrity.

Background: It has been hypothesized that in renal failure, exogenous glycation compounds from food accumulate and play a major pathogenetic role when renal excretion is impaired., Methods: To address this, a diet containing a defined amount of the lysine Amadori product (AP) lactuloselysine was used. Plasma concentrations and cumulative urinary excretion of AP were assessed in 16 healthy subjects, 12 renal failure patients and 6 continuous ambulatory peitoneal dialysis (CAPD) patients. Amadori product was measured as furosine using reverse phase high performance liquid chromatography (RP-HPLC) after acid hydrolysis., Results: A diet low in glycation compounds significantly decreased excretion of APs in healthy subjects. In healthy individuals, ingestion of lactuloselysine bound to food proteins caused only a minor acute increase (8.24+/-1.11 mg/day, 2% of the administered dose) of AP excretion in the urine; in patients with renal failure not yet on dialysis, the increase in AP excretion in the urine was significantly less (4.0+/-0.51 mg/day) and the same was true in CAPD patients (0.21+/-0.09 mg/day). The plasma concentration of total APs, i.e. the sum of APs as free amino acids and residues bound to plasma proteins, did not change in any of the three groups, however., Conclusion: Dietary APs do not accumulate in the blood even in advanced renal failure. The amount of APs measured as furosine excreted in the urine is significantly less, however, in renal failure and CAPD patients compared with healthy subjects. Although the findings exclude accumulation of lactuloselysine in renal failure, they do not generally exclude accumulation of other food-derived advanced glycation end products (AGEs).

Objective: To explore the effect of ecoimmunonutrition on gut barrier function in rats with systemic inflammatory response syndrome (SIRS)., Methods: Rat models of SIRS were established by injecting lipo polysaccharide (LPS) via the tail vein. Sixty male Sprague-Dawley rats were randomly divided into 4 groups. One of the four enteral nutrition formulas (standard EN, immunonutrition, econutrition, ecoimmunonutrition) was given to each group respectively for 7 days. Serum D-lactate, diamine oxidase (DAO), ratio of urinary lactulose to mannitol (L/M) were measured on day 1 before LPS injection (D (-1)) and day 1, 3, 6 after LPS injection (D(+1), D (+3), D (+6))., Results: After 7 days of treatment,the level of serum D-lactate in econutrition group was significantly lower than those in standard EN or immunonutrition group (P< 0.05), and the level of serum D-lactate in all above three groups were significantly higher compared with ecoimmunonutrition group (P< 0.01). The level of serum DAO in standard EN group was higher than those in other three groups(P< 0.01). The L/M was increased in all the groups on D(+1), D(+3). It fell back to the basic level on D(+6)) in all the groups.The L/M in immunonutrition group was lower than those in other groups on D (+1) (P< 0.05), and it was higher in standard EN group than those in other groups on D (+3) (P< 0.01)., Conclusion: Ecoimmunonutrition, a enteral nutrition composed of immune-enhanced nutrient and ecologic, may protect the gut barrier function more effectively in rats with SIRS.

Background: Intestinal permeability is determined by measuring nonmetabolized sugars. In animals, intestinal permeability is determined in urine, using cumbersome and expensive metabolic cages. We developed an HPLC method for determining concentrations of lactulose (L) and L-rhamnose (R) in blood-drop of rabbits and mice, and we compared these results with the procedure based on sugars excreted in urine. We measured the intestinal permeability induced by a fragment (DeltaG) of the zonula occludens toxin which opens the paracellular pathway., Methods: The animals received sugar solution and later received the same solution+DeltaG. Five-hour urine collection and timed blood tests were performed after ingestion of sugars. Sugars were measured with HPLC, and the percentage of recovered sugars was expressed as L/R ratio., Results: At 60 min after administration of sugars, the mean L/R ratio for rabbits and mice was 0.026 and 0.052, respectively. At 60 min after administration of sugars+DeltaG, the mean L/R ratio for rabbits and mice was 0.22 and 0.53. The mean L/R ratio in the urine was 0.023 at basal condition and 0.25 after DeltaG ingestion., Conclusions: Testing small serum samples for sugar permeability is effective for monitoring changes in permeability of the gut in animals. This cheap simple method allows us to measure in vivo the biological activity of other molecules which modulate the paracellular pathway.

Only a few reports have compared the fermentation of pectin and cellulose using the hydrogen-breath test, and no studies have examined the relation between the hydrogen breathing pattern and colonic microflora. Using breath-hydrogen measurements, we investigated whether different dietary fibers (DFs) were fermented differently and whether there were individual differences after ingestion of the same DF; we also examined the relation between individual fecal microflora and the fermentation of DF. Results of hydrogen tests in 14 men were compared after they had ingested 20 g of pectin, 20 g of cellulose, or 6 g of lactulose (a DF-like substance). We examined the relation between the breath hydrogen results and the subjects' fecal microflora. We defined significant fermentation (i.e., positive cases) as a continuous rise in hydrogen in the expiratory air of >19 ppm. The subjects were divided into 3 groups according to their hydrogen breath test pattern, i.e., positive for lactulose and pectin (Group LP, n = 4); positive for lactulose alone (Group L, n = 7); and negative for pectin, cellulose, and lactulose (Group N, n = 3). Individual differences were noted in subjects from Group LP and Group L. The detection frequency of lecithinase-negative clostridia was higher in Group LP than in the other groups (P < 0.05), and the detection frequency and the number of lecithinase-positive clostridia were higher in Groups LP and L than in Group N (P < 0.05). These findings suggest that the Clostridium species are associated with hydrogen production. The hydrogen breath test results of DFs depend on both the type of DF and the individual colonic microflora. The amount and constitution of colonic microflora might be predicted by the hydrogen-breath test using different DFs.

The mechanism of alcohol-mediated increased infection in burn patients remains unknown. With the use of a rat model of acute alcohol and burn injury, the present study ascertained whether acute alcohol exposure before thermal injury enhances gut bacterial translocation. On day 2 postinjury, we found a severalfold increase in gut bacterial translocation in rats receiving both alcohol and burn injury compared with the animals receiving either injury alone. Whereas there were no demonstrable changes in intestinal morphology in any group of animals, a significant increase in intestinal permeability was observed in ethanol- and burn-injured rats compared with the rats receiving either injury alone. We further examined the role of intestinal immune defense by determining the gut-associated lymphoid (Peyer's patches and mesenteric lymph nodes) T cell effector responses 2 days after alcohol and burn injury. Although there was a decrease in the proliferation and interferon-gamma by gut lymphoid T cells after burn injury alone; the suppression was maximum in the group of rats receiving both alcohol and burn injuries. Furthermore, the depletion of CD3(+) cells in healthy rats resulted in bacterial accumulation in mesenteric lymph nodes; such CD3(+) cell depletion in alcohol- and burn-injured rats furthered the spread of bacteria to spleen and circulation. In conclusion, our data suggest that the increased intestinal permeability and a suppression of intestinal immune defense in rats receiving alcohol and burn injury may cause an increase in bacterial translocation and their spread to extraintestinal sites.

The aim of this study was to determine the value of the lactulose mannitol intestinal permeability test in screening the general adult population for unrecognized enteropathy and latent coeliac disease. Subjects with positive serology (identified by screening carried out by the Belfast MONICA Project) along with controls were followed-up after 3 years and classified as having transient serology, persistent serology or coeliac disease. A 5-h urine collection was performed following the ingestion of 5 g lactulose, 2 g mannitol and glucose as an osmotic filler. Urinary concentrations of lactulose and mannitol were measured by enzymatic analysis. Percentage lactulose excretion (%LE) (0.94 versus 0.31, P<0.001) and lactulose mannitol excretion ratio (LMER) (0.12 versus 0.02, P<0.001) were significantly higher in screening-detected coeliac disease subjects compared with MONICA controls. The sensitivity of the permeability test was 87% in the screening situation compared with 81% in the clinical situation. In subjects with persistent and transient serology the LMER did not differ significantly from that of controls. The lactulose-mannitol test is a useful test for screening the general adult population for coeliac disease. Subjects with persistent and transient serology did not differ from MONICA controls and are unlikely to have latent coeliac disease.

Objective: To determine how immediate enteral nutrition (EN) affects gut permeability and the development of multiple organ failure (MOF) in multiply injured patients., Design: Prospective, randomised clinical trial., Setting: 20-bed surgical intensive care unit (ICU), university hospital., Patients: 28 consecutive multiply injured patients, admitted in shock and stabilised in 6 h., Interventions: Patients were randomly assigned to EN started not later than 6 h after admission to the ICU (group A), and to EN started later than 24 h after admission (group B)., Measurements and Main Results: The lactulose/mannitol (L/M) test was performed in patients on days 2 and 4 after trauma, and in 5 healthy volunteers. MOF scores were calculated daily. The mean MOF score from day 4 onwards was 1.84 in group A versus 2.81 in group B (p < 0.002), and was correlated with the time of initiation of EN after injury and the L/M ratio on day 2. The median L/M ratio on day 2 was 0.029 for group A and 0.045 for group B, while on day 4 it was 0.020 and 0.060, respectively. On day 2 after trauma, the L/M ratio was significantly higher in group B (p < 0.05) than in normal volunteers (median 0.014) and was positively correlated with the time of starting EN., Conclusions: In contrast with normal volunteers, the patients started on EN later than 24 h after admission to the ICU demonstrated increased intestinal permeability on the second day after sustaining multiple injury. Also, they had a more severe form of MOF than the group placed on EN immediately upon admission. However, early EN had no influence on the length of ICU stay or the time of mechanical ventilation.

To date, tests of small intestinal passive permeability have involved the ingestion of test molecules whose permeation is assessed indirectly by measuring their urinary recovery. Excretion ratios of marker molecules (eg, lactulose-to-mannitol excretion ratio, LMER) are useful clinically. Measurement of permeability markers in serum would improve the convenience of the tests. Our aim was to assess small intestinal permeability in celiac patients using serum lactulose and mannitol levels with calculation of lactulose to mannitol serum ratios (LMSR) and to compare the results with the standard methods using urinary recoveries. Twenty-four newly diagnosed celiacs and 10 control subjects were studied; 10 celiacs were restudied while established on a gluten-free diet. Test subjects and patients ingested 10 g lactulose and 2.5 g mannitol in 50 ml water. In 10 untreated celiacs and the controls, blood was taken from 0 to 120 min and all urine was collected for 6 hr. The remaining 14 untreated and the 10 treated celiacs had a single serum sample taken 60 min after ingestion of the test solution. At 1 hr after ingestion, the mean mannitol level in normals (0.156 mmol/liter) was significantly higher than in untreated celiacs (0.06 mmol/liter). The 1-hr mean serum lactulose level in normals (0.125 micromol/liter) was significantly lower than in untreated celiacs (0.56 micromol/liter). The median 1-hr LMSR in untreated celiacs was 0.42 compared with 0.039 in normals and 0.08 in treated celiacs. There was a significant correlation between LMSR and LMER. Permeability testing using serum measurements of lactulose and mannitol gave comparable results in celiac patients to the tests using urinary recovery of the permeability markers and may prove to be more convenient, especially in pediatric patients.

A combined test of intestinal permeability using lactulose (L) and rhamnose (R), and absorptive function using xylose (X) and 3-O-methylglucose (G), was carried out at four, six, eight and 16 weeks of age in 22 healthy control and six gluten-sensitive Irish setter (IS) dogs fed a diet containing a controlled dose of gluten from weaning. Comparisons were made with two groups of 12 healthy control dogs of breeds other than IS, one fed the same diet as the setters and the other fed a gluten-free diet. Gluten-sensitive IS showed a rise in permeability (mean [SEM] urinary L/R) from 0.23 (0.07) at four weeks to 0.39 (0.05) at eight weeks, remaining at 0.36 (0.04) at 16 weeks. These results were significantly higher in gluten-sensitive than control IS at six, eight and 16 weeks, compatible with jejunal biopsy lesions characteristic of gluten-sensitive enteropathy demonstrated in affected dogs at 16 weeks. Urinary L/R ratios of control dogs of breeds other than IS peaked at six weeks 0.27 (0.02), and were significantly higher than those of control IS at six and eight weeks, demonstrating differences in permeability between Irish setter dogs and other breeds at this age. There were no significant differences in urinary X/G ratios at six, eight and 16 weeks of age between any of the groups of dogs challenged with gluten. Urinary L/R and X/G ratios were similar in the control dogs of breeds other than IS fed gluten-containing and gluten-free diets. These findings indicate that intestinal permeability testing of puppies during controlled oral gluten challenge provides a practical screening test for gluten sensitivity in Irish setter dogs at an early age.

We demonstrate that rhamnose, 3-O-methyl-D-glucose, D-xylose and lactulose may be quantified accurately in blood by HPLC and pulsed amperometric detection, thus enabling studies of intestinal permeability and function to be carried out using plasma samples. Prior to HPLC, the endogenous glucose was enzymatically modified to gluconic acid and the protein precipitated. The precision of the quantification of the sugars in plasma (CV: 2.2-5.7%; 8.7-10.6% at very low concentrations) compared well with the quantification in urine. The results for groups of 8 dogs with small intestinal bacterial overgrowth and 12 dogs with inflammatory bowel disease were shown to be significantly different from a group of 20 normal control dogs (P < 0.001), demonstrating the test's value as a diagnostic tool. The normal ranges in blood 2 h post oral administration were determined to be 0.05-0.17 for the lactulose/rhamnose ratio and 0.45-0.65 for the xylose/3-O-methylglucose ratio. This method may be employed advantageously when the collection of urine in intestinal permeability and function tests is difficult.

An electrochemical-HPLC method for the determination of mannitol and lactulose is presented which may facilitate routine testing of intestinal permeability by requiring only a single blood sample instead of a 6-hour urine collection. Chromatographic conditions are described which allow separation of the closely related sugars lactulose and the dietary disaccharides lactose and sucrose. Preliminary results in normal controls and patients with untreated coeliac disease are presented.

We aimed to study the effects of chronic ingestion of short-chain fructooligosaccharides (FOS), an indigestible carbohydrate, on hepatic glucose production, insulin-mediated glucose metabolism, erythrocyte insulin binding, and blood lipids in healthy subjects. Twelve healthy volunteers received either 20 g FOS/d or sucrose for 4 wk in a double-blind crossover design. FOS did not modify fasting plasma glucose and insulin concentrations. Mean (+/- SEM) basal hepatic glucose production was lower after FOS than after sucrose consumption (2.18 +/- 0.10 compared with 2.32 +/- 0.09 mg.kg-1, min-1, respectively; P < 0.02, paired Student's t test). However, neither insulin suppression of hepatic glucose production nor insulin stimulation of glucose uptake measured by hyperinsulinemic clamp was significantly different between the two dietary periods. Erythrocyte insulin binding was also comparable. Serum triacylglycerols, total and high-density- lipoprotein cholesterol, apolipoproteins A-I and B, and lipoprotein(a) were not modified by FOS. To try to understand why FOS did not increase serum lipids, the in vitro production of short-chain fatty acids from FOS was evaluated by using human fecal inoculum and compared with that from lactulose, which was found to increase serum lipids. FOS produced an acetate-propionate ratio two times lower than that of lactulose. We conclude that 4 wk of 20 g FOS/d decreased basal hepatic glucose production but had no detectable effect on insulin-stimulated glucose metabolism in healthy subjects. The colonic fermentation pattern of undigestible carbohydrates may be relevant to predicting their metabolic effects.

The percentage dose of lactulose and mannitol excreted in urine after oral ingestion is used as a noninvasive method of assessing small intestinal permeability. The collection of incomplete or inaccurately timed urine samples can lead to errors in estimation of sugar probe molecules. We describe an HPLC method for the simultaneous determination of lactulose and mannitol in serum after oral ingestion of test sugars. We applied the test to healthy volunteers and to subjects undergoing jejunal biopsy for suspected gluten-sensitive enteropathy. The ratio of concentrations of lactulose and mannitol in serum discriminated well between subjects with a normal biopsy and those with villous atrophy, discrimination being best at 90 min postdose. The results agree well with lactulose:mannitol ratios determined in urine (r= 0.88), and the two methods can be used interchangeably. The determination of mannitol and lactulose in serum provides an acceptable alternative to urine collection and may be particularly useful in young children. It also reduces the time spent on the investigation from 5 h to 90 min.

This study looked at the intestinal permeability and the immune response to enteric bacterial antigens in patients with inflammatory bowel disease (IBD). They were evaluated by using a lactulose tolerance test and measuring blood anti-lipid A antibody concentrations, respectively. The lactulose tolerance tests were performed 22 times in 14 patients with Crohn's disease (CD), 19 times in 12 patients with ulcerative colitis (UC), and 12 times in 12 healthy controls. Blood lactulose concentrations were measured after oral administration every two hours for eight hours, also blood C reactive protein concentrations and anti-lipid A antibody concentrations were measured just before lactulose administration. Blood lactulose concentrations were significantly higher in patients with CD than in the controls from two to eight hours after administration, while in UC they were significantly higher than in the controls from six to eight hours. Maximum blood lactulose concentrations in each tolerance test in patients with the active phase significantly exceeded those in the inactive phase of either CD or UC. A significant correlation was also seen between the maximum blood lactulose concentrations and the C reactive protein concentrations. Blood anti-lipid A antibody concentrations in patients with CD were significantly higher than in the controls as well as in patients with UC in immunoglobulin (Ig) A class and IgG class. In UC they were significantly higher than in the controls in IgA class. But, they were not related to the severity of the disease of either CD or UC, and not correlated significantly with the maximum blood lactulose concentrations in either CD or UC. The intestinal permeability and the immune response to enteric bacterial antigens in patients with inactive CD were significantly increased over those in the controls as well as in patients with inactive UC. These findings suggest that an increase of the intestinal permeability and that of producing antibodies to enteric bacterial antigens are both important for the pathogenesis of IBD, and that the characteristics of CD and UC differ.

The absorption, metabolism, space distribution, renal excretion and natural occurrence of mannitol was studied in healthy human volunteers to determine its suitability for use as a probe marker of gastrointestinal permeability. Urinary recovery following oral loading was 8.0-39.6% of the ingested amount. Net absorption during intubation experiments in which a 30 cm segment of small intestine was perfused was 3.6% of perfusate mannitol. The slow rate of removal from the jejunum suggests that mannitol has a very low affinity for facilitated transport systems. Urinary recovery of intravenously injected mannitol approached 100% and renal clearance averaged 131 ml/min. The space distribution, progression of renal excretion and falling plasma concentration simulated that of lactulose rather than 3-0-methyl-D-glucose suggesting a mainly extracellular distribution. This was supported by measurement of erythrocyte penetration. Stool cultures degraded mannitol to products which included acid and carbon dioxide, when incubated aerobically and anaerobically. Excretion of mannitol, which was found to be naturally present in urine, was reduced but not abolished by fasting. Since mannitol occurs naturally in human urine we conclude that measurement of urinary mannitol following oral administration to assess intestinal permeability may be subject to error.

1. A simple oral loading technique involving the ingestion of solutions containing lactulose is described. Timed urinary excretion of lactulose, which is non-metabolizable, is used as an indicator of intestinal permeability, and measured by quantitative paper chromatography. 2. This technique has been used to investigate the intestinal permeability of apparently healthy adults following the ingestion of solutions made hypertonic by the addition of the solutes sucrose, glucose, mannitol, glycerol, urea and sodium chloride. 3. These experiments show that intestinal permeability to lactulose increases as the solute concentration in the ingested solution is increased. Susceptibility to this effect, though consistent for each individual, shows considerable variation between subjects. 4. Factors thought to be pernitent to the enhancement of intestinal permeability by hypertonic solutions, and some possible implications of this, are discussed.

Mammalian cells require cholesterol for normal cell function. This requirement can be fulfilled by endogenous biosynthesis or by extracellular supplementation. Infants fed with human milk receive greater quantities of cholesterol than those fed commercial formulas. Whether this lack of cholesterol in commercial formulas poses a threat to normal neonatal cell function is not known. We compared small intestinal microvillus membrane fluidity, hydrolase activities, protein concentration, permeability to nonabsorbable markers, and weight gain in neonatal piglets receiving restricted intake of isocaloric formulas containing either normal amounts of cholesterol (145 mg/dl) or very low levels of cholesterol (less than 2 mg/dl). Using the fluorescent probe, diphenylhexatriene, and fluorescence polarization, microvillus membranes from cholesterol deprived piglets demonstrated higher fluidities than did microvillus membranes from animals fed normal concentrations of cholesterol. Cholesterol-deprived animals, even though their caloric intake was similar to cholesterol-fed animals, demonstrated a net weight loss per animal whereas the cholesterol-fed animals demonstrated a weight gain. These results demonstrate that in a pig model on a restricted intake, cholesterol deprivation alters the biophysical properties of the microvillus membrane.