Effects of rhein on intestinal epithelial tight junction in IgA nephropathy

AIM: To investigate the effects of rhein on intestinal epithelial tight junction proteins in rats with IgA nephropathy (IgAN).

METHODS: Twenty-eight female Sprague-Dawley rats were randomly divided into four groups (7 per group): Control, IgAN, Rhein-treated, and Rhein-prevented. Bovine serum albumin, lipopolysaccharide and CCl₄ were used to establish the rat model of IgA nephropathy. The Rhein-treated group was given rhein from week 7 until the rats were sacrificed. The Rhein-prevented group was given rhein from week 1. Animals were sacrificed at the end of week 10. We observed the changes in the intestinal epithelial tight junctions using transmission electron microscopy, and expression of intestinal epithelial tight junction proteins zona occludens protein (ZO)-1 and occludin by immunofluorescence using laser confocal microscopy. Changes in mRNA and protein expression of ZO-1 and occludin were measured by reverse transcriptase polymerase chain reaction and Western blotting. The ratio of urinary lactulose/mannitol was measured by high performance liquid chromatography (HPLC) for assessing the intestinal permeability.

RESULTS: In the control group, the tight junctions lied between epithelial cells on the top of the outer side of the cell membrane, and appeared in dense dotted crystal structures, the neighboring cells were binded tightly with no significant gap, and the tight junction protein ZO-1 and occludin were evenly distributed in the intestinal epithelial cells at the top of the junction. Compared with the control group, in the IgAN group, the structure of the tight junction became obscured and the dotted crystal structures had disappeared; the fluorescence of ZO-1 and occludin was uneven and weaker (5.37 ± 1.27 vs 10.03 ± 1.96, P < 0.01; 4.23 ± 0.85 vs 12.35 ± 4.17, P < 0.01); the mRNA expression of ZO-1 and occludin decreased (0.42 ± 0.19 vs 0.92 ± 0.24, P < 0.01; 0.40 ± 0.15 vs 0.97 ± 0.25, P < 0.01); protein expression of ZO-1 and occludin was decreased (0.85 ± 0.12 vs 1.98 ± 0.43, P < 0.01; 0.72 ± 0.15 vs 1.38 ± 0.31, P < 0.01); and the ratio of urinary lactulose/mannitol increased (3.55 ± 0.68 vs 2.72 ± 0.21, P < 0.01). In the Rhein-prevented and Rhein-treated groups, compared with the IgAN group, the intestinal epithelial tight junctions were repaired; fluorescence of ZO-1 and occludin was stronger (11.16 ± 3.52 and 8.81 ± 2.30 vs 5.37 ± 1.27, P < 0.01; 10.97 ± 3.40 and 9.46 ± 2.40 vs 4.23 ± 0.85, P < 0.01); mRNA of ZO-1 and occludin increased (0.81 ± 0.17 and 0.64 ± 0.16 vs 0.42 ± 0.19, P < 0.01; 0.82 ± 0.22 and 0.76 ± 0.31 vs 0.40 ± 0.15, P < 0.01); protein expression of ZO-1 and occludin was increased (2.07 ± 0.41 and 1.57 ± 0.23 vs 0.85 ± 0.12, P < 0.01; 1.34 ± 0.21 and 1.15 ± 0.17 vs 0.72 ± 0.15, P < 0.01); and the ratio of urinary lactulose/mannitol decreased (2.83 ± 0.43 and 2.87 ± 0.18 vs 3.55 ± 0.68, P < 0.01).

CONCLUSION: Rhein can enhance the expression of ZO-1 and occludin, repair damaged tight junctions, and protect the intestinal barrier.

Effects of different resuscitation fluid on severe acute pancreatitis

AIM: To compare effects of different resuscitation fluid on microcirculation, inflammation, intestinal barrier and clinical results in severe acute pancreatitis (SAP).

METHODS: One hundred and twenty patients with SAP were enrolled at the Pancreatic Disease Institute between January 2007 and March 2010. The patients were randomly treated with normal saline (NS group), combination of normal saline and hydroxyethyl starch (HES) (SH group), combination of normal saline, hydroxyethyl starch and glutamine (SHG group) in resuscitation. The ratio of normal saline to HES in the SH and SHG groups was 3:1. The glutamine (20% glutamine dipeptide, 100 mL/d) was supplemented into the resuscitation liquid in the SHG group. Complications and outcomes including respiratory and abdominal infection, sepsis, abdominal hemorrhage, intra-abdominal hypertension, abdominal compartment syndrome (ACS), renal failure, acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), operation intervention, length of intensive care unit stay, length of hospital stay, and mortality at 60 d were compared. Moreover, blood oxygen saturation (SpO₂), gastric intramucosal pH value (pHi), intra-abdominal pressure (IAP), inflammation cytokines, urine lactulose/mannitol (L/M) ratio, and serum endotoxin were investigated to evaluate the inflammatory reaction and gut barrier.

RESULTS: Compared to the NS group, patients in the SH and SHG groups accessed the endpoint more quickly (3.9 ± 0.23 d and 4.1 ± 0.21 d vs 5.8 ± 0.25 d, P < 0.05) with less fluid volume (67.26 ± 28.53 mL/kg/d, 61.79 ± 27.61 mL/kg per day vs 85.23 ± 21.27 mL/kg per day, P < 0.05). Compared to the NS group, incidence of renal dysfunction, ARDS, MODS and ACS in the SH and SHG groups was obviously lower. Furthermore, incidence of respiratory and abdominal infection was significantly decreased in the SH and SHG groups, while no significant difference in sepsis was seen. Moreover, less operation time was needed in the SH and SHG group than the NS group, but the difference was not significant. The mortality did not differ significantly among these groups. Blood SpO₂ and gastric mucosal pHi in the SH and SHG groups increased more quickly than in the NS group, while IAP was significantly decreased in the SH and SHG group. Moreover, the serum tumor necrosis factor-α, interleukin-8 and C-reactive protein levels in the SH and SHG groups were obviously lower than in the NS group at each time point. Furthermore, urine L/M ratio and serum endotoxin were significantly lower in the SH group and further decreased in the SHG group.

CONCLUSION: Results indicated that combination of normal saline, HES and glutamine are more efficient in resuscitation of SAP by relieving inflammation and sustaining the intestinal barrier.

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

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.

Increased intestinal permeability in malnourished patients with liver cirrhosis

BACKGROUND/OBJECTIVE

Malnutrition is a prominent feature in liver cirrhosis, with deleterious impact on clinical outcome. The objective of this study is to investigate whether malnutrition is associated with increased gastrointestinal permeability in liver cirrhosis reflected by altered urinary excretion of non-metabolizable sugar probes.

SUBJECTS/METHODS

Patients with advanced liver cirrhosis (Child Pugh Score B or C) were recruited. Nutritional status was determined according to the Subjective Global Assessment. Intestinal permeability was assessed by measuring the urinary excretion of orally administered, non-metabolized sugar probe molecules. The lactulose/mannitol ratio served as marker for intestinal permeability and reflects non-carrier-mediated transcellular and paracellular transport of the small intestine during the first 5 h. Sucrose recovery in urine within the first 5 h reflects gastroduodenal permeability; sucralose recovery in urine 5-26 h after consumption reflects colonic permeability.

RESULTS

Sixty-four patients (56.7±10.8 years; 33% female) were included in the study. Twenty-one patients were considered well nourished according to the Subjective Global Assessment, 23 moderately nourished and 20 patients severely malnourished; 74% had alcoholic liver disease and 67% had cirrhosis stage Child C. Gastroduodenal and colonic permeability was significantly increased in patients with liver cirrhosis compared with 63 healthy controls (0.23±0.22 and 1.37±1.42% vs 0.14±0.10 and 0.41±0.72% in controls), but not different between well and malnourished subjects. Small intestinal permeability (lactulose/mannitol ratio) was increased in all patients (0.069±0.055%) and further increased in malnourished patients (0.048±0.031% vs 0.084±0.061%, P=0.004) due to decreased mannitol recovery only.

CONCLUSIONS

Gastric, small intestinal and even colonic permeability was altogether increased in liver cirrhosis, and malnutrition was associated with further increased small intestinal permeability indicative of villous atrophy.

Novel multi-sugar assay for site-specific gastrointestinal permeability analysis: a randomized controlled crossover trial

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).

Association between intestinal and antioxidant barriers in children with cancer

OBJECTIVE

Reactive oxygen species (ROS) play a role in cancerogenesis processing and damage tissues. Furthermore, oncological treatment may impair proper function of the gut barrier. The aim of this study was to measure intestinal permeability in children in clinical remission for solid tumours and to search for a possible relationship between free radicals and the intestinal barrier. No such investigation in children has been reported so far.

RESEARCH METHODS AND PROCEDURES

The prospective study consisted of 19 paediatric patients with cancer after completion of chemotherapy. 32 healthy children from the outpatients clinics were recruited for measurement of intestinal permeability and antioxidant barrier as a control group. Intestinal permeability was assessed by measurement of urinary lactulose and mannitol after oral challenge. Antioxidant enzymes: superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in erythrocytes were assessed. Ischemia modified albumin (IMA) concentration was measured in serum.

RESULTS

Cancer patients excreted less mannitol and more lactulose versus controls. The ratio of lactulose to mannitol was significantly higher in oncological children vs control (mean 0.188 and 0.0453, respectively, p=0.0006,). Significantly higher IMA level in the oncological group vs control was noted (mean 123.8 and 87.3 U/ml, respectively, p=0.0037). No correlation between intestinal permeability and oxidative stress barrier was found.

CONCLUSIONS

Our data shows that intestinal barrier is damaged in paediatric cancer patients after chemotherapy. IMA is believed to play a protective role in the defence against tissue damage. No correlation was found between these two barriers.

Urine sugars for in vivo gut permeability: validation and comparisons in irritable bowel syndrome-diarrhea and controls

Mucosal barrier dysfunction contributes to gastrointestinal diseases. Our aims were to validate urine sugar excretion as an in vivo test of small bowel (SB) and colonic permeability and to compare permeability in patients with irritable bowel syndrome-diarrhea (IBS-D) to positive and negative controls. Oral lactulose (L) and mannitol (M) were administered with (99m)Tc-oral solution, (111)In-oral delayed-release capsule, or directly into the ascending colon (only in healthy controls). We compared L and M excretion in urine collections at specific times in 12 patients with IBS-D, 12 healthy controls, and 10 patients with inactive or treated ulcerative or microscopic colitis (UC/MC). Sugars were measured by high-performance liquid chromatography-tandem mass spectrometry. Primary endpoints were cumulative 0-2-h, 2-8-h, and 8-24-h urinary sugars. Radioisotopes in the colon at 2 h and 8 h were measured by scintigraphy. Kruskal-Wallis and Wilcoxon tests were used to assess the overall and pairwise associations, respectively, between group and urinary sugars. The liquid in the colon at 2 h and 8 h was as follows: health, 62 ± 9% and 89 ± 3%; IBS-D, 56 ± 11% and 90 ± 3%; and UC/MC, 35 ± 8% and 78 ± 6%, respectively. Liquid formulation was associated with higher M excretion compared with capsule formulation at 0-2 h (health P = 0.049; IBS-D P < 0.001) but not during 8-24 h. UC/MC was associated with increased urine L and M excretion compared with health (but not to IBS-D) at 8-24 h, not at 0-2 h. There were significant differences between IBS-D and health in urine M excretion at 0-2 h and 2-8 h and L excretion at 8-24 h. Urine sugars at 0-2 h and 8-24 h reflect SB and colonic permeability, respectively. IBS-D is associated with increased SB and colonic mucosal permeability.

Assessment of intestinal permeability using sugar probes: influence of urinary volume

BACKGROUND

As the accuracy of the "Sugar Test" is currently debated, this study was conducted to focus on how urine volumes may impact the test results.

METHODS

Fifty-five subjects, 23 healthy and 32 with Irritable Bowel Syndrome (IBS), were enrolled. Lactulose and D-mannitol dissolved in water were administered to all the participating subjects; the urine excreted was collected and the total urine volume was measured. The urine samples were analyzed by High Performance Liquid Chromatography (HPLC). The results were expressed as percentage of urine recovery of lactulose and D-mannitol and lactulose/D-mannitol ratio (LMR).

RESULTS

All subjects were divided into two groups: subjects with urine volume < 500 mL and subjects with urine volume > or = 500 mL. Urine analysis showed that the mean LMR was significantly lower in subjects with urine volume > or = 500 mL than in subjects with urine volume < 500 mL (0.02 +/- 0.02 vs 0.04 +/- 0.04; p < 0.05). A significant increase in D-mannitol recovery was found to be associated with greater urine volumes (p < 0.001).

CONCLUSIONS

The urine volume may influence urinary excretion of sugar probes. Intake of liquids should therefore be carefully monitored before and during the test and the volume of urine produced over the period of collection should be precisely measured.

[The change of intestinal mucosa barrier in chronic severe hepatitis B patients and clinical intervention]

OBJECTIVE

To study the change of intestinal mucosa barrier in chronic severe hepatitis B patients and clinical intervention.

METHOD

(1) 30 normal healthy controls and 60 chronic severe hepatitis B patients were enrolled in this study. The change of intestinal permeability was determined by urine lactulose/ mannitol ratio (L/M), and the serum diamine oxidase (DAO) was measured. (2) 60 chronic severe hepatitis B patients were randomly divided into two groups: the control group and the treated group, each group has 30 cases. Patients in the control group received standard treatment for 2 weeks, however, in addition to standard treatment, patients in the treated group also received glutamine 10g tid. Endotoxin (ET), DAO and L/M were compared between the two group.

RESULTS

(1) Compared to healthy controls, the level of L/M and DAO was significantly increased in chronic severe hepatitis B patients (t = 2.762, P less than 0.01 or t = 6.326, P less than 0.01). (2) Compared to the control group, ET, DAO and L/M were significantly lower 2 weeks after treatment (F = 11.662, P less than 0.01; F = 12.699, P less than 0.01; F = 19.981, P less than 0.01).

CONCLUSION

(1) There is an early intestinal mucosa barrier damage in chronic severe hepatitis B patients. (2) Compared to standard treatment, adding glutamine can reverse intestinal mucosa barrier damage.

[A study of urine lactulose/mannitol ratio and intestinal fatty acid binding protein as the indexes of intestinal damage in sepsis]

OBJECTIVE

To assess urine lactulose/mannitol ratio (LMR), and intestinal fatty acid binding protein (IFABP) concentration as the indexes of intestinal damage in septic patients, and to evaluate the clinical severity and mortality of septic patients by use of these indexes.

METHODS

Thirty-eight patients with sepsis were consecutively selected in Beijing Friendship Hospital intensive care unit (ICU) from June 2007 to February 2008, according to the inclusions and exclusions criteria. Urine samples were taken in 72 hours after ICU admission. Urine LMR was determined by high performance liquid chromatography by use of pulsed electrochemical detection (HPLC-PED), and urine IFABP concentration was determined by enzyme-linked immunosorbent assays (ELISA). The results of LMR and IFABP were analyzed with acute physiology and chronic health evaluation II (APACHE II) score, with multiple organ dysfunction syndrome (MODS) or not and outcome on day 28. The relationship between the two indexes and the patients' gastrointestinal function score was analyzed.

RESULTS

Thirty-eight patients included had significantly higher urine level of IFABP concentration and LMR. Urine LMR were higher in patients with APACHE II score > 20 than in patients with APACHE II score < or =20 (P = 0.056), and the values were significantly higher in patients who with MODS and in nonsurvivors than those in patients who without MODS and in survivors (both P < 0.05). Urine IFABP concentration was not found significantly difference in patients with APACHE II score > 20, those with MODS and nonsurvivors, compared with patients with APACHE II score < or = 20, those without MODS and survivors. Patients with stress ulcer had higher urine IFABP concentration than patients without stress ulcer (P < 0.05). There was no correlation among LMR, IFABP and gastrointestinal function score.

CONCLUSION

This study reveals that patients with sepsis have intestinal mucosal damage and increased intestinal permeability. Increased LMR in urine is associated with clinical severity and prognosis; urine IFABP concentration is not associated with clinical severity and prognosis. Patients with stress ulcer have higher urine IFABP concentration. There is no correlation among IFABP, LMR and gastrointestinal function score.

Assessment of small intestinal permeability using 1H-NMR spectroscopy

BACKGROUND

Evaluation of small intestinal permeability (SIP) is based on the estimation of the urinary excretion ratio of a large and a small molecule (lactulose and mannitol, L/M) after oral administration. We evaluated SIP using 1H-NMR spectroscopy.

METHODS

In-vitro experiments on known concentration of mannitol and lactulose solutions were performed to measure accuracy and precession of quantification using 1H-NMR spectroscopy. Eighteen patients with malabsorption syndrome (MAS) and 28 healthy subjects (HS) underwent SIP evaluation using L/M excretion ratio over 6-h after oral administration of 15 mL (10g) lactulose and 5 g mannitol using 1H-NMR spectroscopy and trimethyl silyl propionic acid as external reference and for quantification.

RESULTS

Median errors of estimation of mannitol and lactulose were 5% (range 1.2 to 5) and 1.3% (range 0.2 to 1.3), respectively in-vitro. Patients with MAS excreted higher quantity of lactulose in urine than HS (median 0.33 mmol vs 0.12, 0 to .676 mmol, p<0.008). There was a trend towards lower urinary excretion of mannitol in patients with MAS than HS (median 3.58, range 0.61 to 15.77 mmol vs. 3.82, 1.34 to 16.42 mmol, p = ns). L/M ratio was higher among patients with MAS as compared to HS (median 0.1172 vs 0.045, p< 0.002). A cut-off value of L/M excretion ratio by receiver-operating characteristic (ROC) curve of 0.049 had a sensitivity and specificity of 72% and 61%, respectively; a cut-off value of 0.078 had a specificity of 90% but low sensitivity (67%). Area under ROC curve was 0.77.

CONCLUSION

1H-NMR spectroscopy is an analytical tool for assessment of SIP with reasonable sensitivity and specificity.

Intestinal permeability and malabsorption of rifampin and isoniazid in active pulmonary tuberculosis

Low antimycobacterial drug concentrations have been observed in tuberculosis (TB) patients under treatment. The lactulose/mannitol urinary excretion test (L/M), normally used to measure intestinal permeability, may be useful to assess drug absorption. The objective of this research was to study intestinal absorptive function and bioavailability of rifampin and isoniazid in TB patients. A cross sectional study was done with 41 patients and 28 healthy controls, using the L/M test. The bioavailabilities of rifampin (R) and isoniazid (H) were evaluated in 18 patients receiving full doses. Urinary excretion of mannitol and lactulose, measured by HPLC, was significantly lower in TB patients. The serum concentrations of the drugs were below the expected range for R (8-24 mcg/mL) or H (3-6 mcg/mL) in 16/18 patients. Analyzing the drugs individually, 12/18 patients had low serum concentrations of R, 13/18 for H and 8/18 for both drugs. We suggest that there is a decrease in the functional absorptive area of the intestine in TB patients, which would explain the reduced serum concentrations of antituberculosis drugs. There is a need for new approaches to improve drug bioavailability in TB patients.

Measurement of intestinal mucosal permeability in dogs with lymphocytic-plasmacytic enteritis

Lymphocytic-plasmacytic enteritis (LPE) is a type of canine inflammatory bowel disease (IBD). One of its most probable causes is a defect in the mucosal permeability barrier. In the present study, intestinal permeability in LPE dogs was examinated to evaluate its clinical value. Twenty-nine dogs with LPE diagnosed by clinical and histological examinations were included in this study. Intestinal permeability was evaluated by measuring the ratio of the concentrations of two sugars (lactulose (L) and rhamnose (R)) with different molecular weights in urine samples after oral administration of a solution containing them. Biopsy specimens of duodenum were evaluated according to histological criteria. The urinary L:R ratio in the 29 LPE dogs (1.68 +/- 1.17, mean +/- SD) was significantly higher than that in the 10 healthy control dogs (0.75 +/- 0.38, P<0.01). In the LPE dogs, a weak correlation was observed between the histopathological grading score of the duodenum and the urinary L:R ratio (r=0.408, P<0.05). The urinary L:R ratio in the 20 dogs showing hypoalbuminemia (< 2.5 g/dl) was significantly higher than that in the 9 dogs with normal serum albumin levels > 2.5 g/dl (P<0.01). In conclusion, permeability of the intestinal mucosa as determined by the urinary L:R ratio could be a useful laboratory parameter for evaluating intestinal damage in LPE dogs.

Fluid restriction during running increases GI permeability

The purpose of this study was to determine gastrointestinal (GI) permeability during prolonged treadmill running (60 min at 70 % V.O2max) with and without fluid intake (3 ml/kg body mass/10 min). Twenty runners (11 males, 9 females; age = 22 +/- 3 (SD) yrs; mean V.O2max = 55.7 +/- 5.0 ml/kg/min) completed four experiments: 1) rest, 2) running with no fluid (NF), 3) running with ingestion of a 4 % glucose solution (GLU), and 4) running with ingestion of a water placebo (PLA). To determine GI permeability, subjects also drank a solution containing 5 g sucrose (S), 5 g lactulose (L), and 2 g rhamnose (R) immediately prior to each trial. Gastroduodenal permeability was determined by urinary S excretion, while small intestinal permeability was determined by the L/R excretion ratio. Percent body mass loss (i.e., dehydration) was negligible during rest, GLU and PLA, while NF resulted in a 1.5 % loss of body mass (p < 0.05). Gastroduodenal and intestinal permeability were significantly (p < 0.008) increased in NF compared to rest. There were no other differences in GI permeability. These results indicate that fluid restriction during 1 h of steady-state running increases GI permeability above resting levels.

Effects of oral adenosine 5'-triphosphate and adenosine in enteric-coated capsules on indomethacin-induced permeability changes in the human small intestine: a randomized cross-over study

Background

It is well-known that nonsteroidal anti-inflammatory drugs (NSAIDs) can cause damage to the small bowel associated with disruption of mucosal barrier function. In healthy human volunteers, we showed previously that topical administration of adenosine 5'-triphosphate (ATP) by naso-intestinal tube attenuated a rise in small intestinal permeability induced by short-term challenge with the NSAID indomethacin. This finding suggested that ATP may be involved in the preservation of intestinal barrier function. Our current objective was to corroborate the favourable effect of ATP on indomethacin-induced permeability changes in healthy human volunteers when ATP is administered via enteric-coated capsules, which is a more practically feasible mode of administration. Since ATP effects may have been partly mediated through its breakdown to adenosine, effects of encapsulated adenosine were tested also.

Methods

By ingesting a test drink containing 5 g lactulose and 0.5 g L-rhamnose followed by five-hour collection of total urine, small intestinal permeability was assessed in 33 healthy human volunteers by measuring the urinary lactulose/rhamnose excretion ratio. Urinary excretion of lactulose and L-rhamnose was determined by fluorescent detection high-pressure liquid chromatography (HPLC). Basal permeability of the small intestine was assessed as a control condition (no indomethacin, no ATP/adenosine). As a model of increased small intestinal permeability, two dosages of indomethacin were ingested at 10 h (75 mg) and 1 h (50 mg) before ingesting the lactulose/rhamnose test drink. At 1.5 h before indomethacin ingestion, two dosages of placebo, ATP (2 g per dosage) or adenosine (1 g per dosage) were administered via enteric-coated hydroxypropyl methylcellulose (HPMC) capsules with Eudragit^© L30D-55.

Results

Median urinary lactulose/rhamnose excretion ratio (g/g) in the control condition was 0.032 (interquartile range: 0.022–0.044). Compared to the control condition, lactulose/rhamnose ratio after ingestion of indomethacin plus placebo was significantly increased to 0.039 (0.035–0.068); P < 0.01). The indomethacin-induced increase was neither affected by administration of encapsulated ATP (0.047 (0.033–0.065)) nor adenosine (0.050 (0.030–0.067)). Differences in L/R ratios between the conditions with indomethacin plus placebo, ATP or adenosine were not significant.

Conclusion

In this study, either ATP or adenosine administered via enteric-coated capsules had no effect on indomethacin-induced small intestinal permeability changes in healthy human volunteers. The observed lack of effect of encapsulated ATP/adenosine may have been caused by opening of the enteric-coated supplement at a site distal from the indomethacin-inflicted site. Further studies on site-specific effectiveness of ATP/adenosine on intestinal permeability changes are warranted.

[Effect of hepatocyte growth factor on intestinal permeability and bacterial translocation after small bowel transplantation in rat]

OBJECTIVE

To evaluate the effect of hepatocyte growth factor (HGF) on intestinal permeability and bacterial translocation after small bowel transplantation in rats.

METHODS

Twenty Wistar rats were as receptors and twenty SD rats as donors. After heterotopic intestinal grafting, cyclosporine A was administered at 6 mg/kg x day intramuscularly for inhibiting rejection. The SD rats were divided into 2 groups (n = 10). HGF was administered at 150 microg/kg x day (HGF group) and normal saline was administered at 150 microg/kg x day (control group). Intestinal permeability and bacterial translocation to the mesenteric lymph nodes and portal vein were assessed at the 8th postoperative day.

RESULTS

The lactulose and lactulose/ mannitol of control group (0.0931%+/-0.0085% and 0.132+/-0.021) were higher than those of normal reference value (0.0150%+/-0.0020% and 0.020+/-0.005) (P < 0.05). The lactulose and lactulose/ mannitol of HGF group (0.0396%+/-0.0090% and 0.056+/-0.013) were also higher than those of normal reference value (P<0.05). The bacterial culture positive proportion of lymphaden in HGF group and control group were 10% and 60%, showing statistically significant difference (P<0.05). The bacterial culture positive proportion of portal vein in HGF group and control group were 10% and 20% respectively (P>0.05).

CONCLUSION

HGF can decrease intestinal permeability and bacterial translocation from the lumen of the graft to the mesenteric lymph nodes, thus improve gut barrier function, may be of help to reduce the incidence of septic complications after intestinal grafting.

Intestinal permeability and antigliadin antibody test for monitoring adult patients with celiac disease

Celiac disease causes chronic inflammation of the intestinal mucosa and reduces surface absorption; after the withdrawal of gluten from the diet, there are clinical and histologic improvements. The intestinal permeability test and serologic tests are useful for confirming the diagnosis and monitoring patients. The goal of this study is to compare the antigliadin antibody (AGA) test with the intestinal permeability test for celiac patients on a gluten-free diet. The sample consisted of 22 celiac patients who were antigliadin immunoglobulin A-positive before treatment. After 12 months on a gluten-free diet, AGA testing was repeated and the intestinal permeability test was performed. A control group was composed of 11 healthy individuals. AGA remained positive in 40.9% of celiac patients, and the mean urinary lactulose excretion was 10.27%, that of mannitol was 10.18%, and the lactulose/mannitol ratio was 1.02. In the subgroup in which antigliadin became negative (59.1%), the value for lactulose was 3.79%, that for mannitol was 11.12%, the lactulose/mannitol ratio was 0.38, and the p value was less than 0.0001, 0.66, and less than 0.0001, respectively. When the two celiac subgroups were compared with the control group, the urinary lactulose excretion and the lactulose/mannitol ratio was less in the control group, whereas urinary mannitol excretion was greater. The p values were less than 0.0001 for the three variables, suggesting persistent lesions in mucosa of both subgroups, although to a lesser degree for those that became AGA negative. It is concluded that intestinal permeability allows a more precise clinical physiopathologic correlation than antigliadin and offers more information for the monitoring of these patients.

Local effect of adenosine 5'-triphosphate on indomethacin-induced permeability changes in the human small intestine

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID) use is associated with an elevated risk of gastrointestinal damage. As adenosine 5'-triphosphate (ATP) may play a protective role in the small intestine, our objective was to determine the local effect of ATP on small intestinal permeability changes induced by short-term challenge of the NSAID indomethacin in healthy humans.

METHODS

Mucosal permeability of the small intestine was assessed by the lactulose/rhamnose permeability test, that is, ingestion of a test drink containing 5 g lactulose and 0.5 g L-rhamnose followed by total urine collection for 5 h. Urinary excretion of lactulose and L-rhamnose was determined by fluorescent detection high-pressure liquid chromatography (HPLC). Basal small intestinal permeability was assessed as a control condition. As a model of increased small intestinal permeability, two doses of indomethacin were ingested before ingestion of the test drink (75 mg and 50 mg at 10 h and 1 h before the test drink, respectively). Concomitantly with indomethacin ingestion, placebo or 30 mg/kg ATP was administered through a naso-intestinal tube.

RESULTS

Median urinary lactulose/rhamnose ratio (g/g) in the control condition was 0.023 (interquartile range: 0.013-0.041). Compared with the control condition, urinary lactulose/rhamnose ratio after ingestion of indomethacin and administration of placebo was significantly increased [0.042 (0.028-0.076); P<0.01]. In contrast, urinary lactulose/rhamnose ratio after indomethacin ingestion plus ATP administration [0.027 (0.020-0.046)] was significantly lower than the lactulose/rhamnose ratio in the placebo condition (P<0.01).

CONCLUSIONS

Topical ATP administration into the small intestine during short-term challenge of the NSAID indomethacin attenuates the NSAID-induced increase in small intestinal permeability in healthy humans.

Intestinal permeability in different feedings in infancy

AIM

To determine the intestinal permeability (IP) as a marker of intestinal epithelial integrity in formula-fed infants compared with healthy breast-fed infants.

METHODS

IP was measured in 57 healthy infants less than 4 months old. A dual sugar test with lactulose and mannitol was performed. Three urinary ratios were established: lactulose/mannitol (L/M), lactulose/creatinine (L/C) and mannitol/creatinine (M/C). Five groups were studied: breast-fed (n = 11), prebiotic supplemented formula (n 17), nucleotides supplemented formula (n = 9), LC-PUFA supplemented formula (n = 9) and LC-PUFA and nucleotides supplemented formula (n = 11).

RESULTS

We have not found any difference in IP between breast-fed and formula-fed infants nor when the different formulas are compared with each other. The indirect information of the paracellular pathway by the ratio L/C and the transcellular route by the ratio M/C reflects some difference when the ingredients added are fructooligosaccharides and galactooligosaccharides, expressing a higher degree of lactulose permeation with respect to mannitol. When LC-PUFA supplementation was evaluated a lesser ratio of L/C was found, expressing intestinal barrier related to a process of epithelial tight.

CONCLUSIONS

The most important factor in the maintenance of the integrity of epithelial barrier function is probably the delivery of nutrients in the gastrointestinal tract. The role of the different ingredients added should be clarified.

Effect of hyperbilirubinemia on intestinal permeability in healthy term newborns

We investigated the effect of serum bilirubin (SB) on intestinal permeability (IP) of healthy, term, birth weight appropriate for gestational age neonates before phototherapy. IP was measured by the dual probe (lactulose/mannitol) sugar absorption test (SAT) performed on the third day of life in 12 healthy jaundiced newborns (total bilirubin 249 +/- 39.75 micromol/L) and compared to that of 12 non-jaundiced newborns (total bilirubin 83.79 + 37.62 micromol/L) matched for sex, gestational age, birth weight and Apgar score. Jaundiced newborns have a significantly higher La/Ma ratio than non-jaundiced (0.31 +/- 0.28 vs. 0.053 +/- 0.043; p < 0.0004). A significant correlation was found between serum bilirubin level and La/Ma ratio (r = 0.56 p < 0.006).

CONCLUSION

Our study demonstrates a direct effect of UCB on gut epithelial barrier of at-term newborns in whom UCB appears to be responsible for an alteration of IP that theoretically may lead to a passage of macromolecules through the intestinal epithelium increasing the risk of sensitization.

The effect of glutamine-enriched enteral nutrition on intestinal permeability in very-low-birth-weight infants: a randomized controlled trial

BACKGROUND

Very-low-birth-weight (VLBW) infants are susceptible to glutamine depletion. Glutamine depletion has negative effects on intestinal integrity. The lower infection rate in VLBW infants receiving glutamine-enriched enteral nutrition may originate from improved intestinal integrity, as reflected by decreased intestinal permeability. The aim of our study was to investigate whether glutamine-enriched enteral nutrition in VLBW infants enhances the normal decrease in intestinal permeability, as measured by the sugar absorption test (SAT).

METHODS

In a double-blind, randomized, placebo-controlled trial, VLBW infants (gestational age <32 weeks or birth weight <1,500 g) received enteral glutamine supplementation (0.3 g/kg/d) or an isonitrogenous placebo supplementation (alanine) between days 3 and 30 of life. Intestinal permeability, determined from the urinary lactulose/mannitol (L/M) ratio after an oral dose of lactulose and mannitol, was assessed at 4 time points: before the start of the study, and at days 7, 14, and 30 of life.

RESULTS

At least 2 SATs were performed in 45/52 (86%) and 45/50 (90%) infants in the glutamine-supplemented and control groups, respectively. Baseline patient and nutrition characteristics were not different between the groups. There was no effect of glutamine-enriched enteral nutrition on the decrease of the L/M ratio between the start and end of the study (p = .78). In both treatment groups, median urinary lactulose concentrations decreased (p < .001), whereas median urinary mannitol concentrations increased (p = .003).

CONCLUSIONS

Glutamine-enriched enteral nutrition does not enhance the postnatal decrease in intestinal permeability in VLBW infants. Any beneficial effect of glutamine may involve other aspects of intestinal integrity; for example, modulation of the intestinal inflammatory response.

Intestinal permeability in patients with adverse reactions to food

BACKGROUND

An abnormal intestinal permeability could contribute to establish an altered sensitivity to food-allergen.

AIM

To evaluate the intestinal permeability in subjects with adverse reactions to food on allergen-free diet.

SUBJECTS

Twenty-one patients with food allergy and 20 with food hypersensitivity on allergen-free diet were enrolled and divided in four groups according to the seriousness of their referred clinical symptoms when they were on a free diet.

METHODS

Intestinal permeability was evaluated by Lactulose/Mannitol ratio urinary detection determined by anion-exchange chromatography.

RESULTS

Statistically significant different Lactulose/Mannitol ratio was evidenced in subjects with food allergy (p=0.003) or hypersensitivity (p=0.0008) compared to control patients. The correlation between Lactulose/Mannitol ratio and the seriousness of clinical symptoms, by using Spearman test, was statistically significant for food allergy (p=0.0195) and hypersensitivity (p=0.005) patients.

CONCLUSIONS

The present data demonstrate that impaired intestinal permeability, measured in our conditions, is present in all subjects with adverse reactions to food. In addition, for the first time, we report a statistically significant association between the severity of referred clinical symptoms and the increasing of Intestinal Permeability Index. These data reveal that intestinal permeability is not strictly dependent on IgE-mediated processes but could better be related to other mechanisms involved in early food sensitisation, as breast-feeding, or microbial environment that influence the development of oral tolerance in early infancy.

Intestinal Permeability and Cytokine Inflammatory Response in Multiply Injured Patients

In experimental settings, the increased intestinal permeability (IP) following severe trauma is associated with increased serum concentrations of cytokines. Multiply injured patients are susceptible to the development of multiple organ failure (MOF). The aim of this study was to determine if altered IP after trauma was associated with upregulation of cytokines and if cytokines and IP influenced the development of MOF. In 30 multiply injured patients, IP was measured on days 2 and 4 after injury using the lactulose-mannitol (L-M) test, and the levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-8 were determined simultaneously. The L-M ratio increased significantly from 0.049 (0.017-0.133) on day 2 to 0.150 (0.059-0.339) on day 4 (p < 0.02) On day 4, a significant correlation was also found between the L-M ratio and IL-6 (r = 0.43, p < 0.03). The IL-6 level on days 2 and 4 was significantly (p < 0.01 and p < 0.03, respectively) higher in MOF patients than in those without MOF, as was the TNF-alpha level on day 4 significantly higher (p < 0.04) in MOF patients. IP increases following multiple trauma, and on day 4 it correlates with the IL-6 level. However, in patients who develop MOF only cytokines are invariably increased, with IL-6 alone being significantly increased on both measurements in these patients.

Lactulose and mannitol intestinal permeability detected by capillary electrophoresis

Aim of this study was to set up a method by capillary electrophoresis to detect lactulose and mannitol in urine after an oral load, and to estimate the intestinal permeability in controls and in type I diabetes patients. The underivatized carbohydrates were monitored by indirect UV detection using sorbate, cetyltrimethylammonium bromide and LiOH as background electrolyte. Urines were purified by solid phase extraction, shaken with cation exchange resin, filtered and analysed. Carbohydrates migrated in <10 min in relation to their pK(a) and M(r). Controls (n = 33) and patients (n = 23) had an excretion ratio lactulose/mannitol 0.025 (0.018-0.051) and 0.067 (0.050-0.127), respectively (p < 0.01, median, interquartile range).