Increased Intestinal Permeability and Decreased Resiliency of the Intestinal Barrier in Alcoholic Liver Disease

INTRODUCTION

Only 20%-30% of individuals with alcohol use disorder (AUD) develop alcoholic liver disease (ALD). While the development of gut-derived endotoxemia is understood to be a required cofactor, increased intestinal permeability in ALD is not completely understood.

METHODS

We recruited 178 subjects-58 healthy controls (HCs), 32 with ALD, 53 with AUD but no liver disease (ALC), and 35 with metabolic dysfunction-associated steatotic liver disease (MASLD). Intestinal permeability was assessed by a sugar cocktail as a percentage of oral dose. The permeability test was repeated after an aspirin challenge in a subset.

RESULTS

Five-hour urinary lactulose/mannitol ratio (primarily representing small intestinal permeability) was not statistically different in HC, ALC, ALD, and MASLD groups ( P = 0.40). Twenty-four-hour urinary sucralose (representing whole gut permeability) was increased in ALD ( F = 5.3, P < 0.01) and distinguished ALD from ALC; 24-hour sucralose/lactulose ratio (primarily representing colon permeability) separated the ALD group ( F = 10.2, P < 0.01) from the MASLD group. After aspirin challenge, intestinal permeability increased in all groups and ALD had the largest increase.

DISCUSSION

In a group of patients, we confirmed that (i) the ALD group has increased intestinal permeability compared with the HC, ALC, or MASLD group. In addition, because small bowel permeability (lactulose/mannitol ratio) is normal, the disruption of intestinal barrier seems to be primarily in the large intestine; (ii) decreased resiliency of intestinal barrier to injurious agents (such as NSAID) might be the mechanism for gut leak in subset of AUD who develop ALD.

Effects of nutritional therapy on gastrointestinal microbial digestion and barrier defense markers in elderly patients with diabetes

OBJECTIVE

We sought to investigate the effects of gastrointestinal nutrition therapy on gastrointestinal microbial digestion and barrier defense markers in elderly patients with diabetes.

METHODS

A total of 120 elderly patients with type 2 diabetes were enrolled at our hospital between January 2020 and December 2022. The participants in this study were randomly allocated into either the nutritional group (n = 60) who underwent gastrointestinal nutrition therapy or the control group (n = 60) who underwent conventional T2DM diet management for a period of 12 weeks. Clinical data, as well as small intestinal permeability measured by the lactulose-mannitol urine test, plasma circulating IL-6 and zonulin levels measured by ELISA, and expressions of ZO-1 and Claudin-3 in blood analyzed through Western blotting were collected.

RESULTS

The nutrition group demonstrated a higher proportion of patients achieving HbA1c < 7% compared to the control group (P < 0.05). Moreover, the nutrition group exhibited a greater reduction in fasting and postprandial blood glucose levels compared to the control group (P < 0.05). The concentrations of formate-tetrahydrofolate ligase and acetic CoA transferase were significantly increased in the nutrition group compared to the control group (P < 0.05). Fecal analysis revealed higher levels of acetic acid and butyric acid in the nutrition group compared to the control group (P < 0.05). The ratio of lactulose to mannitol was higher in the nutrition group compared to the control group (P < 0.05). Furthermore, the nutrition group showed lower levels of IL-6 and zonulin compared to the control group (P < 0.05).

CONCLUSION

Personalized gastrointestinal nutrition therapy was found to enhance the production of short-chain fatty acids and preserve intestinal permeability, leading to improved gastrointestinal microbial digestion and barrier defense in elderly patients with diabetes.

Plasma measurements of the dual sugar test reveal carbohydrate immediately alleviates intestinal permeability caused by exertional heat stress

The aim of this set of randomised cross-over studies was to determine the impact of progressive heat exposure and carbohydrate or protein feeding during exertional stress on small intestine permeability using a dual sugar test. In our previous work, and typically in the field, recovery of lactulose and l-rhamnose is measured cumulatively in urine. This follow-up study exploits our novel high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) protocol to accurately quantify the sugars in plasma. Endurance-trained participants completed experimental trial A (ET-A; n = 8), consisting of 2 h running at 60%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ in temperate, warm and hot ambient conditions, and/or experimental trial B (ET-B; n = 9), consisting of 2 h running at 60%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ in the heat while consuming water, carbohydrate or protein. Blood samples were collected and plasma lactulose (L) and l-rhamnose (R) appearance, after dual sugar solution ingestion at 90 min of exercise, was quantified by HPAEC-PAD to measure plasma L/R and reveal new information about intestinal permeability immediately post-exercise and during recovery. In ET-A, plasma L/R increased immediately post-exercise in hot compared with temperate and warm conditions, while, in ET-B, carbohydrate alleviated this, and this information was otherwise missed when measuring urine L/R. Consuming carbohydrate or protein before and during exercise attenuated small intestine permeability throughout recovery from exertional heat stress. We recommend using the dual sugar test with quantification of plasma sugars by HPAEC-PAD at intervals to maximise intestinal permeability data collection in exercise gastroenterology research, as this gives additional information compared to urinary measurements. KEY POINTS: Intestinal permeability is typically assessed using a dual sugar test, by administering a drink containing non-metabolisable sugars (e.g. lactulose (L) and l-rhamnose (R)) that can enter the circulation by paracellular translocation when the epithelium is compromised, and are subsequently measured in urine. We demonstrate that our recently developed ion chromatography protocol can be used to accurately quantify the L/R ratio in plasma, and that measuring L/R in plasma collected at intervals during the post-exercise recovery period reveals novel acute response information compared to measuring 5-h cumulative urine L/R. We confirm that exercising in hot ambient conditions increases intestinal epithelial permeability immediately after exercise, while consuming carbohydrate or protein immediately before and during exercise attenuates this. We recommend using our dual sugar absorption test protocol to maximise intestinal epithelial permeability data collection in exercise gastroenterology research and beyond.

Assessment of small-intestine permeability in healthy Nigerian children is altered by urinary volume and voiding status

Objective

This study aimed to uncover the effect of voided urinary volume on small intestine permeability ratios in healthy children.

Methods

We assessed small intestine permeability in 155 apparently healthy children, aged 3–5 years old, without any visible symptoms of disease, in a rural, malaria-endemic setting in Nigeria, using a multi-sugar test solution, comprising lactulose, sucrose, mannitol, and rhamnose. Children were categorized into low urinary volume (LV) and high urinary volume (HV), based on the volume of urine voided per kg body weight per hour. LV children voided less than 25^th percentile of the total population, while HV children voided greater than 75^th percentile of the total population. Urinary volume excreted over a 90-minute period after administration of the test solution was measured, and differences in sugar ratios were compared between children with high (HV) and low urinary volumes (LV), as well as between children who voided (VC) or who were not able to void (NVC) before administration of the test solution.

Results

Urinary mannitol and rhamnose recovery were 44% (p = 0.002) and 77% (p<0.001) higher in HV children compared to LV children respectively, while urinary lactulose recovery was 34% lower (p = 0.071). There was no difference in urinary sucrose recovery between groups (p = 0.74). Lactulose-mannitol ratio, lactulose-rhamnose ratio and sucrose-rhamnose ratio were all significantly higher in children in the LV group compared to children in the HV group (p<0.001). In a multiple regression analysis, urinary volume and voiding status combined, explained 13%, 23% and 7% of the variation observed in lactulose-mannitol, lactulose-rhamnose and sucrose-rhamnose ratios, respectively.

Conclusion

Sugar permeability ratios vary significantly with total urinary volume in multi-sugar small-intestine permeability tests. Voiding status before sugar administration appears to influence lactulose recovery, lactulose-rhamnose and sucrose-rhamnose ratios independently of total urinary volume. Evidence from this study suggests the need to take urinary volume into account when conducting multi-sugar small-intestine permeability tests.

Goat milk protein digestibility in relation to intestinal function

BACKGROUND

Milk is an important high-quality animal protein source in low- and middle-income countries (LMICs). Although the true ileal digestibility and absorption of milk has been shown to be high in French adults, this may be lower in individuals from LMICs who are at risk of environmental enteropathy.

OBJECTIVE

To determine the true ileal indispensable amino acid (IAA) digestibility of intrinsically labeled goat milk protein in South Indian women of reproductive age (WRA), using the dual-isotope tracer technique, and to measure intestinal absorption of amino acid and inert sugar in the same participants using L-allo-isoleucine and a dual-sugar assay.

METHODS

Milk with 2H-labeled protein collected from a lactating goat fed intrinsically 2H-labeled fodder (maize and cowpea) was spray dried. Labeled milk protein was administered in a plateau feeding protocol to WRA with normal BMI, in whom urinary lactulose and mannitol recovery and the lactulose/mannitol ratio (LMR) were measured, to determine its true ileal IAA digestibility by the dual-isotope tracer technique with a reference U-13C-amino acid mixture. A phenylalanine absorption index was calculated from the plasma to meal ratio of 13C9 phenylalanine within the digestibility protocol. On a separate day, the allo-isoleucine absorption index was estimated from the ratio of plasma allo-isoleucine enrichments after oral 13C6-15N-L- and intravenous 2H10-L-allo-isoleucine administration.

RESULTS

The means ± SDs of true ileal IAA digestibility of goat milk protein, lactulose and mannitol recovery, LMR, allo-isoleucine and phenylalanine absorption index were 94.0 ± 2.9%, 0.09 ± 0.03%, 7.9 ± 2.3%, 0.012 ± 0.004, 88.4 ± 3.8% and 24.5 ± 1.6%, respectively. The LMR correlated with the allo-isoleucine absorption index (rs = -0.93, P = 0.008).

CONCLUSION

The true ileal digestibility of goat milk protein in South Indian WRA with normal intestinal absorptive function and integrity was comparable to earlier estimates in healthy French adults.

How is small bowel permeability in endometriosis patients? a case control pilot study

Endometriosis is a chronic inflammatory disease of women of reproductive age. Small bowel (SB) permeability and lipopolysaccharides (LPS) could play a role in the perduration of low grade inflammation status and the pathogenesis of endometriosis. To clarify this hypothesis, we measured SB permeability through plasma values of LPS and urinary secretion of lactulose (La), mannitol (Ma) and their ratio (L/M) in patients with endometriosis compared with healthy controls (HC). Eight patients and 14 HC entered the study. SB permeability was evaluated by high-performance liquid chromatography of urine concentrations of La and Ma. Plasma levels of LPS were measured in the blood. Moreover, a nutritional, gastroenterological, quality of life evaluation was performed through validates questionnaires and complete gynaecological evaluations. The statistical analysis of the obtained data did not show differences in anthropometric and nutritional characteristics and gastrointestinal functional disease in the two groups. Patients reported higher levels of pelvic chronic pain (3.87 ± 2.99 vs 0.15 ± 0.55; pe = 0.001) and significantly higher LPS plasma levels (0.529 ± 0.11 vs 0.427 ± 0.08; p value = .027) than HC. Our results indicate that intestinal permeability is abnormal in endometriosis patients, and it might play a role in the pathogenesis of this chronic disease.

Experimental Assessment of Chemotherapy-induced Early Intestinal Damage in Colon Cancer the Lactulose-mannitol Permeability Test

Aims and Background

Although chemotherapy plays an important role in the management and cure of cancer, it has undesiderable side effects mostly affecting the bone marrow and gastrointestinal tract, which greatly limit patient compliance and treatment efficacy.

Methods

The lactulose-mannitol test was used to assess intestinal mucosa damage 48 hours after the end of the first adjuvant chemotherapy cycle with 5-fluorouracil (5-FU) and levamisole in 12 patients with colon cancer. Fifteen age- and sex-matched subjects were studied as controls. The excreted amount of lactulose and mannitol was expressed as the percentage of the administered doses recovered in the urine as well as their ratio.

Results

The percent urinary recovery of lactulose was significantly (P <0.001) higher in colon cancer patients (1.1 ± 0.5%) than in the control group (0.3 ± 0.03%), whereas the mannitol recovery was only slightly reduced in the former. As a result, the lactulose/mannitol excretion ratio was significantly (P <0.001) higher in colon cancer patients (0.07 ± 0.03) than in the control group (0.01 ± 0.01).

Conclusions

As assessed by the lactulose-mannitol test, the combined chemotherapy regimen with 5-FU and levamisole affects mainly the barrier function of the intestinal mucosa rather than its absorption capacity. The toxic effect seems to be attributable to the 5-FU molecule rather than to levamisole. The lactulose-mannitol test is a simple, safe and reliable tool to evaluate chemotherapy-induced early damage to the intestinal epithelium, in particular when new kinds of substances are being administered. Its use in clinical practice seems appropriate to establish the correct timing of drug administration, thereby enhancing treatment efficacy and improving patient compliance.

Effect of early enteral nutrition (EN) on endotoxin in serum and intestinal permeability in patients with severe acute pancreatitis

OBJECTIVE

This work aimed at studying the effect of early enteral nutrition (EN) on serum endotoxin and intestinal permeability in patients with severe acute pancreatitis.

PATIENTS AND METHODS

70 cases of patients with severe acute pancreatitis were cured in our hospital from April 2015 to January 2016. Patients selected were randomly divided into two groups including a group of patients having parenteral nutrition (group PN) and that had enteral nutrition (group EN). The results were assessed by: 1) the differences of serum endotoxin level; 2) the differences of the lactulose/mannitol ratio of urine, before intervention and one and two weeks after the intervention.

RESULTS

Before the intervention, both groups had similar levels of serum endotoxin and the same lactulose/mannitol excretion rate of urine (p>0.05). One and two weeks after the intervention, the serum endotoxin level and the lactulose/mannitol excretion rate of urine of the group PN were significantly higher than the group EN (p<0.05).

CONCLUSIONS

Compared with PN, EN has a bigger effect on serum endotoxin and intestinal permeability in patients with severe acute pancreatitis. EN can better promote the elimination of serum endotoxin and reduce intestinal permeability. Therefore, EN deserves clinical expansion.

Intestinal fatty acid-binding protein and gut permeability responses to exercise

PURPOSE

Intestinal cell damage due to physiological stressors (e.g. heat, oxidative, hypoperfusion/ischaemic) may contribute to increased intestinal permeability. The aim of this study was to assess changes in plasma intestinal fatty acid-binding protein (I-FABP) in response to exercise (with bovine colostrum supplementation, Col, positive control) and compare this to intestinal barrier integrity/permeability (5 h urinary lactulose/rhamnose ratio, L/R).

METHODS

In a double-blind, placebo-controlled, crossover design, 18 males completed two experimental arms (14 days of 20 g/day supplementation with Col or placebo, Plac). For each arm participants performed two baseline (resting) intestinal permeability assessments (L/R) pre-supplementation and one post-exercise following supplementation. Blood samples were collected pre- and post-exercise to determine I-FABP concentration.

RESULTS

Two-way repeated measures ANOVA revealed an arm × time interaction for L/R and I-FABP (P < 0.001). Post hoc analyses showed urinary L/R increased post-exercise in Plac (273% of pre, P < 0.001) and Col (148% of pre, P < 0.001) with post-exercise values significantly lower with Col (P < 0.001). Plasma I-FABP increased post-exercise in Plac (191% of pre-exercise, P = 0.002) but not in the Col arm (107%, P = 0.862) with post-exercise values significantly lower with Col (P = 0.013). Correlations between the increase in I-FABP and L/R were evident for visit one (P = 0.044) but not visit two (P = 0.200) although overall plots/patterns do appear similar for each.

CONCLUSION

These findings suggest that exercise-induced intestinal cellular damage/injury is partly implicated in changes in permeability but other factors must also contribute.

Lubiprostone improves intestinal permeability in humans, a novel therapy for the leaky gut: A prospective randomized pilot study in healthy volunteers

BACKGROUND AND AIMS

The barrier function of the small intestinal mucosa prevents the introduction of undesired pathogens into the body. Breakdown of this barrier function increases intestinal permeability. This has been proposed to induce not only gastrointestinal diseases, including inflammatory bowel disease and irritable bowel syndrome, but also various other diseases, including allergies, diabetes mellitus, liver diseases, and collagen diseases, which are associated with this so called "leaky gut syndrome." As such, a method to prevent leaky gut syndrome would have substantial clinical value. However, no drugs have been demonstrated to improve disturbed intestinal permeability in humans to date. Therefore, we investigated whether a drug used to treat chronic constipation, lubiprostone, was effective for this purpose.

METHODS

Healthy male volunteers were treated with lubiprostone (24 μg/day) for 28 days. Intestinal permeability was evaluated by measuring the lactulose-mannitol ratio (LMR) after administration of diclofenac and compared with an untreated group. The examination was conducted three times in total, i.e., at baseline before diclofenac administration and after 14 and 28 days of lubiprostone treatment. Blood endotoxin activity was also evaluated at the same time points.

RESULTS

The final analysis was conducted on 28 subjects (14 in the lubiprostone group and 14 in the untreated group). The LMR after 28 days of treatment was significantly lower in the lubiprostone group than that in the untreated group (0.017 vs. 0.028, respectively; 95% confidence interval, -0.022--0.0001; p = 0.049). Blood endotoxin activity exhibited almost no change over time in the lubiprostone and untreated groups and displayed no significant differences at any time point of examination.

CONCLUSIONS

This study is the first to report an improvement in leaky gut using an available drug in humans. The result suggests that lubiprostone may prevent and ameliorate "leaky gut syndrome". However, a pivotal trial is needed to confirm our finding.

NMR-based urinary profiling of lactulose/mannitol ratio used to assess the altered intestinal permeability in acute on chronic liver failure (ACLF) patients

The article presents a simplified NMR-based protocol for urinary profiling of lactulose/mannitol ratio (LMR) and demonstrates here its utility to assess increased intestinal permeability (IP) in patients with acute on chronic liver failure (ACLF). ACLF is a serious clinical complication associated with chronic liver disease (cirrhosis). The major risk factor in its development is increased IP ('leaky gut'), which has been linked to disease progression and to infectious complications. However, IP has seldom been investigated in patients with ACLF, even though patients frequently report gastrointestinal disorders and associated complications. To this end, we first optimized the NMR-based targeted profiling of urinary metabolites (i.e. actulose, mannitol, and creatinine) and subsequently used this resulted protocol (a) first to evaluate the altered IP in ACLF patients and then (b) to explore its utility for monitoring the treatment response in these patients. The normal profiles were obtained for 7 age and sex matched healthy volunteers. The results revealed that the urinary LMR excretion was significantly higher in ACLF patients compared to normal controls (median ~0.7, range (0.12-2.84), vs median ~0.11, range (0.02-0.28), p < 0.001) suggesting that the ACLF patients' exhibit altered IP. However, the LMR excretion in six clinically improved follow-up ACLF patients was comparable to normal controls indicating restored IP after the treatment. The protocol-as demonstrated here with ACLF-is equally applicable for evaluating IP or mucosal barrier function in other intestinal disorders with reasonable sensitivity and specificity, highlighting its general utility. Copyright © 2016 John Wiley & Sons, Ltd.

Undernutrition, Vitamin A and Iron Deficiency Are Associated with Impaired Intestinal Mucosal Permeability in Young Bangladeshi Children Assessed by Lactulose/Mannitol Test

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.

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

Background

Although organoboronic acids are efficient high-throughput sugar sensors, they have not been pursued for gut permeability studies. A modification of the lactulose/mannitol assay is described by which small intestinal permeability is assessed at the time of urine collection using a lactulose/riboflavin ratio.

Methods

Volunteers ingested 50 mg riboflavin and either 5 g mannitol or 10 g lactulose. Urine was collected for 6 hrs. Riboflavin was assayed by autofluorescence. Riboflavin was removed by C18 solid phase extraction. Lactulose and mannitol were then assayed using 1,1′-bis(2-boronobenzyl)-4,4′-bipyridinium (4,4′oBBV) coupled to the fluorophore HPTS.

Results

The temporal profile over 6 hrs for riboflavin paralleled mannitol. Riboflavin recovery in urine was 11.1 ± 1.9 % (mean ± SEM, n = 7), similar to mannitol. There was selective binding of 4,4′oBBV to lactulose, likely involving cooperativity between the fructose and galactose moieties. Lower limits of detection and quantification were 90 and 364 μM. The lactulose assay was insensitive to other permeability probes (e.g., sucrose, sucralose) while tolerating glucose or lactose. This assay can be adapted to automated systems. Stability of 4,4′oBBV exceeds 4 years.

Conclusions

Riboflavin measured by autofluorescence combined with lactulose measured with 4,4′oBBV represents a useful new chemistry for rapid measurement of intestinal permeability with excellent stability, cost and throughput benefits.

Standardising the lactulose mannitol test of gut permeability to minimise error and promote comparability

BACKGROUND

Lactulose mannitol ratio tests are clinically useful for assessing disorders characterised by changes in gut permeability and for assessing mixing in the intestinal lumen. Variations between currently used test protocols preclude meaningful comparisons between studies. We determined the optimal sampling period and related this to intestinal residence.

METHODS

Half-hourly lactulose and mannitol urinary excretions were determined over 6 hours in 40 healthy female volunteers after administration of either 600 mg aspirin or placebo, in randomised order at weekly intervals. Gastric and small intestinal transit times were assessed by the SmartPill in 6 subjects from the same population. Half-hourly percentage recoveries of lactulose and mannitol were grouped on a basis of compartment transit time. The rate of increase or decrease of each sugar within each group was explored by simple linear regression to assess the optimal period of sampling.

KEY RESULTS

The between subject standard errors for each half-hourly lactulose and mannitol excretion were lowest, the correlation of the quantity of each sugar excreted with time was optimal and the difference between the two sugars in this temporal relationship maximal during the period from 2½-4 h after ingestion. Half-hourly lactulose excretions were generally increased after dosage with aspirin whilst those of mannitol were unchanged as was the temporal pattern and period of lowest between subject standard error for both sugars.

CONCLUSION

The results indicate that between subject variation in the percentage excretion of the two sugars would be minimised and the differences in the temporal patterns of excretion would be maximised if the period of collection of urine used in clinical tests of small intestinal permeability were restricted to 2½-4 h post dosage. This period corresponds to a period when the column of digesta column containing the probes is passing from the small to the large intestine.

Influence of urine volume on the assessment of intestinal permeability in affected children by multiple sugar probes

BACKGROUND

In this study we have looked at the reliability of a multi-sugar test in a pediatric patient population and its accuracy at small urine volumes to evaluate intestinal permeability.

METHODS

Out of 117 subjects enrolled, 31 were healthy and 86 were sick. A solution containing lactulose, rhamnose, sucrose, and sucralose was administered to subjects who were on fasting; the urine excreted during 5 h was collected and measured. Samples were analyzed by gas chromatography-tandem mass spectrometry and results were expressed as percentage of sugar recoveries and lactulose/rhamnose (L/R) ratio.

RESULTS

The analyses showed a clear effect of low urinary volumes (≤240 mL) particularly affecting rhamnose excretion in healthy subjects and sucrose and sucralose recovery in diseased children. Despite the low rhamnose recovery, as lactulose is not similarly affected, the diagnostic reliability of L/R ratio is well preserved at low diuresis conditions. However, this ratio can be useful to discriminate acute conditions vs. clinical remissions only at high urine volumes. Data also suggest potential diagnostic applicability of sucrose and sucralose in children at high urine volumes.

CONCLUSIONS

In conclusion, the multi-sugar test has a good predictivity in pediatric subjects but results must be carefully interpreted in the face of reduced diuresis.

A pilot study examining the relationship among Crohn disease activity, glucagon-like peptide-2 signalling and intestinal function in pediatric patients

BACKGROUND⁄

OBJECTIVES

The relationship between the enteroendocrine hormone glucagon-like peptide 2 (GLP-2) and intestinal inflammation is unclear. GLP-2 promotes mucosal growth, decreases permeability and reduces inflammation in the intestine; physiological stimulation of GLP-2 release is triggered by nutrient contact. The authors hypothesized that ileal Crohn disease (CD) affects GLP-2 release.

METHODS

With ethics board approval, pediatric patients hospitalized with CD were studied; controls were recruited from local schools. Inclusion criteria were endoscopy-confirmed CD (primarily of the small intestine) with a disease activity index >150. Fasting and postprandial GLP-2 levels and quantitative urinary recovery of orally administered 3-O-methyl-glucose (active transport) and lactulose⁄mannitol (passive) were quantified during the acute and remission phases.

RESULTS

Seven patients (mean [± SD] age 15.3 ± 1.3 years) and 10 controls (10.3 ± 1.6 years) were studied. In patients with active disease, fasting levels of GLP-2 remained stable but postprandial levels were reduced. Patients with active disease exhibited reduced glucose absorption and increased lactulose⁄mannitol recovery; all normalized with disease remission. The change in the lactulose⁄mannitol ratio was due to both reduced lactulose and increased mannitol absorption.

CONCLUSIONS

These findings suggest that pediatric patients with acute ileal CD have decreased postprandial GLP-2 release, reduced glucose absorption and increased intestinal permeability. Healing of CD resulted in normalization of postprandial GLP-2 release and mucosal functioning (nutrient absorption and permeability), the latter due to an increase in mucosal surface area. These findings have implications for the use of GLP-2 and feeding strategies as a therapy in CD patients; further studies of the effects of inflammation and the GLP-2 axis are recommended.

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.

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).

Is a leaky gut involved in the pathogenesis of intrahepatic cholestasis of pregnancy?

Increased gastrointestinal permeability has been demonstrated in several liver diseases. It may facilitate the absorption of gut-derived endotoxin-stimulating Kupffer cells to release proinflammatory cytokines or other potentially hepatotoxic compounds. We examined gastrointestinal permeability, plasma levels of anti-lipopolysacharides (anti-LPS), and four proinflammatory cytokines in 20 patients with intrahepatic cholestasis of pregnancy (ICP) compared with 22 normal pregnant and 29 non-pregnant women. Urinary excretion of sucrose and the urinary lactulose/mannitol (L/M) ratio after a standard oral load were used to assess gastrointestinal permeability. Anti-LPS (IgA, IgM, and IgG) were measured in peripheral blood by Human EndoCAb test kit; TNF-alpha, IL-1beta, IL-6, and IL-10 by Quantikine HS human immunoassays. Sucrose urinary excretion was similar in the three groups, indicating normal gastric permeability. The urinary L/M ratio was significantly higher in ICP than in the other groups [median (interquartile range): 0.018% (0.011-0.023) in ICP, 0.012% (0.009-0.016) in normal pregnancies, and 0.009% (0.008-0.012) in non-pregnant women, P < .01]. No significant differences were found in anti-LPS or cytokines plasma levels except slightly higher levels of IL-6 in ICP patients than in non-pregnant women (P < .05). Four of five women with abnormal urinary L/M ratio during ICP continued to show abnormalities in tests up to 2 years after delivery. In conclusion, an increased intestinal permeability was detected in ICP patients during and after pregnancy. A "leaky gut" may participate in the pathogenesis of ICP by enhancing the absorption of bacterial endotoxin and the enterohepatic circulation of cholestatic metabolites of sex hormones and bile salts.

Iron supplementation increases small intestine permeability in primary schoolchildren in Lusaka, Zambia

Elevated intestinal permeability, measured as an increased lactulose:mannitol (L:M) ratio, indicates injury of the small intestinal mucosa. As part of a randomized iron and multi-micronutrient (without iron) supplementation trial (Nchito et al., 2004), we determined intestinal permeability in a subgroup of schoolchildren at 10 months' follow-up to assess the effect of the interventions. Among 153 children (mean age 10.2 years and 53.6% girls) iron supplementation resulted in a higher L:M ratio compared with placebo (0.29 vs. 0.21, P=0.025). There was no effect of multi-micronutrient supplementation, and no interaction between the interventions. The finding could be one of the mechanisms explaining the negative effects of medicinal iron supplementation on morbidity found in some other studies.

Glutamine-enriched total parenteral nutrition in patients with inflammatory bowel disease

BACKGROUND

Studies in animal models of inflammatory bowel disease (IBD) suggest that supplementation of total parenteral nutrition with glutamine (gln), a conditionally essential amino acid in catabolic conditions, increases gln plasma concentrations, reduces intestinal damage, improves nitrogen balance and may improve the course of the disease. However, human data supporting this assumption are missing.

METHODS

A total of 24 consecutive patients with an acute exacerbation of IBD (19 Crohn's disease; five ulcerative colitis) and scheduled for total parenteral nutrition (TPN) (>7 days) were randomised. Parallel to a standardised anti-inflammatory therapy, the patients received either a TPN with 1.5 g/kg body weight of a standard amino acid or an isonitrogenic, isocaloric TPN with 1.2 g/kg body weight of a standard amino acid and 0.3 g/kg L-alanine-L-glutamine. Primary end points were gln plasma concentrations and intestinal permeability assessed by urinary lactulose and D-xylose ratio.

RESULTS

Gln plasma levels did not differ significantly in either group throughout the study. Intestinal permeability did not change within 7 days either with or without gln supplementation (Delta-lactulose/xylose ratio: 0.01+/-0.05 (gln+) vs 0.02+/-0.1 (gln-)). The observed changes in inflammatory and nutritional parameters, and also disease activity, length of TPN and hospital stay, were independent of glutamine substitution. Five (41%) patients in the gln+ group and three (25%) patients in the gln- group needed surgical intervention.

CONCLUSION

Although limited by the sample size, these results do not support the hypothesis that glutamine substitution has an obvious biochemical or clinical benefit in patients with active IBD scheduled for total parenteral nutrition.

Effect of Lactobacillus GG on intestinal integrity in Malawian children at risk of tropical enteropathy

BACKGROUND

Tropical enteropathy is an asymptomatic villous atrophy of the small bowel that is prevalent in the developing world and is associated with altered intestinal function and integrity. The histology of tropical enteropathy resembles that seen in small-bowel bacterial overgrowth.

OBJECTIVE

This study tested the hypothesis that treatment of 3-5-y-old Malawian children with the probiotic Lactobacillus GG would improve their intestinal function and integrity.

DESIGN

Clinically healthy children (n = 164) were enrolled in a placebo-controlled, randomized, double-blind trial. Intestinal function and integrity were measured by using the site-specific sugar-absorption test before and after 30 d of treatment with Lactobacillus GG or placebo. The primary outcomes were the ratios of urinary lactulose to mannitol (L:M) and of urinary sucrose to lactulose (S:L) excretion.

RESULTS

Of the 161 children who completed the study, 119 (73%) had tropical enteropathy on enrollment (L:M > 0.10). Children receiving Lactobacillus GG did not differ significantly from the placebo group in the excretion (in % of dose administered) of mannitol (mean +/- SD: 8.9 +/- 4.4 and 8.9 +/- 3.9, respectively), lactulose (0.31 +/- 0.20 and 0.33 +/- 0.23, respectively), or sucrose (0.078 +/- 0.058 and 0.082 +/- 0.075, respectively). L:M and S:L also did not differ significantly between the Lactobacillus and placebo groups (0.19 +/- 0.13 and 0.20 +/- 0.12, respectively, for L:M; 0.58 +/- 0.46 and 0.65 +/- 0.57, respectively, for S:L).

CONCLUSION

Administration of Lactobacillus GG for 30 d had no effect on the intestinal integrity of 3-5-y-old Malawian children.

Prospective evaluation of gut mucosal barrier injury following various myeloablative regimens for haematopoietic stem cell transplant

We determined gut mucosal barrier injury (MBI) among 129 recipients of an allogeneic or autologous haematopoietic stem cell transplant (HSCT) who had been given different myeloablative regimens by measuring integrity using the lactulose/rhamnose (RHA) ratio and absorption using the ratios of rhamnose/3-O-methylglucose and xylose/3-O-methylglucose. Regimens that did not contain idarubicin induced oral mucositis and disturbed gut integrity and absorption earlier than did those containing the anthracycline. By contrast, regimens containing idarubicin induced more severe and prolonged oral and gut MBI. Gut integrity and absorption of most patients were still abnormal at discharge from hospital. These results confirm that the integrity and absorptive capacity of the gut is affected adversely by myeloablative regimens in general, although only two patterns of mucosal injury emerged depending on whether or not idarubicin was used.

Prebiotic ingestion does not improve gastrointestinal barrier function in burn patients

Prebiotics increase intestinal levels of health-promoting bacteria implicated in decreasing pathogen colonization, stimulating immune functions and stabilizing gut barrier functions, parameters which are altered in burn patients. We propose that regular intake of a prebiotic, oligofructose (OF), might help to improve the altered gastrointestinal (GI) permeability observed in burn patients. A randomized, double-blind, controlled clinical trial was carried out in 41 burn patients (mean burn surface area=17.1+/-8.2%) who ingested daily 6 g of oligofructose (OF group) or sucrose as placebo (Control group) during 15 days. Gastrointestinal permeability to sucrose and lactulose/mannitol (L/M) was evaluated on days 1 (before treatment) 3, 7, 14 and 21. A permeability test was also performed in 18 healthy subjects as controls. Thirty-one patients completed the protocol (dropout rate=24.4%). Healthy subjects had a basal sucrose excretion of 21.3 mg (14.0-32.5 mg) and a basal L/M ratio of 0.017% (0.009-0.022%). Sucrose excretion increased 5-fold and L/M ratio 4.4-fold in burn patients on day 1 and these high levels of marker excretion decreased significantly throughout the study (p=0.016 and 0.000001, respectively). No differences between the OF and Control groups were observed for sucrose excretion or L/M ratio. In conclusion, the normalization of gastrointestinal permeability is not accelerated by prebiotic intake.

Evaluation of a triple sugar test of colonic permeability in humans

AIM

Conventional dual sugar tests of intestinal permeability assess only the stomach and small intestine. A novel triple sugar method of assessing colonic permeability has recently been described in animals. This utilizes the non-fermented sweetener sucralose, in addition to conventional sugars. It has been postulated that this test enables the simultaneous assessment of small-intestinal and colonic barrier function in humans. The aim of this study was to evaluate the triple sugar test using healthy volunteers and ileostomists.

METHODS

Twenty-one healthy volunteers and 18 ileostomists underwent the triple sugar test. After an overnight fast, subjects drank a solution containing lactulose (5 g), rhamnose (1 g) and sucralose (5 g). Urine was collected for 0-5 h and 5-19 h. Urinary sugars were quantified using HPLC, and 5 and 24-h excretion calculated. Nineteen control subjects and 16 ileostomists also underwent a 51Cr-EDTA permeability test. Permeability data were presented as medians (IQR), and differences between groups analysed with Mann-Whitney U-tests.

RESULTS

Lactulose excretion and the 5-h lactulose/rhamnose (L/R) ratio were similar in controls and ileostomists [L/R ratio 0.024 (0.022-0.034) vs. 0.025 (0.022-0.035), P = 0.955]. Twenty-four hours excretion of sucralose was significantly higher in control subjects compared with ileostomists [1.41% (1.17-1.68) vs. 0.96% (0.64-1.2), P = 0.003]. The same pattern was seen with 51Cr-EDTA [2.73% (2.06-3.76) vs. 2.06% (1.55-2.71), P = 0.037] and with lactulose [0.52% (0.42-0.60) vs. 0.25% (0.16-0.35), P = 0.002].

CONCLUSIONS

Both sucralose and 51Cr-EDTA underwent significant colonic absorption. A significant amount of lactulose also appeared to be absorbed in the colon. This unexpected finding requires further study.

Studies on intestinal permeability of cirrhotic patients by analysis lactulose and mannitol in urine with HPLC/RID/MS

The method for separation and determination of lactulose (L) and mannitol (M) in urine was developed by HPLC with a refractive index detector (RID). The linearity ranged from 5 to 1000 microg/mL for L and M, respectively. Recoveries ranged from 93.1% to 97.1%. The intra- and inter-day relative standard deviations of peak area were between 0.8-1.4% (n=3) and 1.4-3.6% (n=3). The limits of detection were obtained with 1.40 microg/mL for L and 1.65 microg/mL for M. The ratios of L/M in the urine samples for the spontaneous ascitic fluid infection (SAI), sterile ascitic fluid (SA) patients, and healthy volunteers (HV) were determined. The results showed well the correlations among the L/M ratio, intestinal permeability (IP) and the illness status of patients, and also indicated lactulose could improve the IP of SAI patients. The peaks of L and M in chromatograms were identified by electrospray ionization/mass spectrometry (ESI/MS), which ensured the accurate measurement of the ratio L/M. This method presented a rapid, accurate, and practical technique for determining IP in clinical practice and investigating the pathology of hepatocirrhosis.

Gut permeability in paediatric cardiac surgery

BACKGROUND

Intestinal mucosal ischaemia can occur in infants and children during and after cardiac surgery. Severe decreases in mucosal perfusion may cause complications such as necrotizing enterocolitis and postoperative mortality. We investigated gut permeability in paediatric patients undergoing cardiac surgery using the dual sugar permeability test and absorption of two other saccharides.

METHODS

Thirty-four patients undergoing palliative or corrective surgical procedures with and without cardiopulmonary bypass were investigated. Intestinal permeability was measured using 3-O-methyl-D-glucose, D-xylose, L-rhamnose and lactulose, given orally after induction of anaesthesia and 12 and 24 h later.

RESULTS

Lactulose/rhamnose ratios were raised from the outset [median 0.39 (confidence interval 0.07-1.8 for patients undergoing operations without cardiopulmonary bypass and 0.30 (0.02-2.6) with cardiopulmonary bypass]. The highest lactulose/rhamnose ratios were recorded 12 h after surgery 0.32 (0.07-6.9), when cardiopulmonary bypass was used. This is approximately seven times the value expected in healthy children. There was an improvement in patients not undergoing cardiopulmonary bypass: 0.22 (0.03-0.85) 12 h and 0.11 (0-0.48) 24 h after induction of anaesthesia. Patients undergoing repair of aortic coarctation showed the fastest recovery: 0.09 (0.03-0.31) 12 h and 0.07 (0.04-0.35) 24 h after induction of anaesthesia.

CONCLUSIONS

Patients with congenital heart defects have abnormal gut permeability when compared with healthy children of similar age. Cardiopulmonary bypass seems to affect the intestinal barrier morphologically (lactulose and rhamnose absorption) and functionally (3-O-methyl-D-glucose and D-xylose absorption).

Effect of glutamine on change in early postoperative intestinal permeability and its relation to systemic inflammatory response

AIM: To study the effects of glutamine (Gln) on the change of intestinal permeability and its relationship to systemic inflammatory response in early abdominal postoperative patients.

METHODS: A prospective, randomized, double-blind and controlled trial was taken. Twenty patients undergoing abdominal surgery were randomized into Gln group (oral administration of glutamine, 30 g/d, for 7 d, n = 10) and placebo group (oral administration of placebo, 30 g/d, for 7 d, n = 10). Temperatures and heart rates of all patients were daily recorded. White blood cell counts (WBC) and biochemical variables were measured before operation and 4 and 7 d after drug administration. Serum concentrations of glutamine, endotoxin, diamine oxidase and malondialdehyde and urine lactulose/mannito (L/M) ratio were measured before and 7 d after drug administration.

RESULTS: The patients in the 2 groups were comparable prior to drug administration. Serum Gln concentration was significantly decreased in the placebo group and increased in the Gln group 7 d after drug administration. Urine L/M ratio was significantly increased in the placebo group and decreased in the Gln group. The serum concentration of endotoxin, diamine oxidase and malondialdehyde was significantly decreased in the Gln group compared with those in the placebo group. Temperatures, heart rates and WBC counts were significantly lower in the Gln group than those in the placebo group.

CONCLUSION: Gut is one of the sources of systemic inflammatory response in abdominal postoperative patients and glutamine can decrease intestinal permeability, maintain intestinal barrier and attenuate systemic inflammatory response in early postoperative patients.