Cellobiose/mannitol sugar test--a sensitive tubeless test for coeliac disease: results on 1010 unselected patients

Small Bowel Permeability in Diagnosis of Celiac Disease and Monitoring of Compliance of a Gluten-Free Diet (Gut Permeability in Celiac Disease)

Background & Aim: Celiac disease is an autoimmune disease with the damage of the intestinal barrier. The aim of study was to measure gut permeability in patients with untreated celiac disease and during treatment with a gluten free diet. Methods: 30 patients with celiac disease before and during treatment with gluten-free diet were investigated, 30 patients without organic damage of the gastrointestinal tract served as control. Small bowel permeability was measured using lactulose/mannitol and lactulose/D-xylose ratios. The saccharides were examined in the 5 hours collected urine using capillary gas chromatography. Results: Small bowel permeability (indices lactulose/mannitol and/or lactulose/xylose) increased significantly in patients with untreated celiac disease. 23 patients were followed up before and during treatment with a gluten-free diet 2-6 months after beginning of this treatment and small bowel permeability (measured as indices lactulose/ mannitol and/or lactulose/xylose) significantly decreased. Conclusion: Small bowel permeability test is a non-invasive test suitable for the diagnosis of celiac disease and monitoring of compliance to a gluten-free diet in these patients.

Platelet number in different anticoagulants as a diagnostic biomarker for increased intestinal permeability

The main pathological process associated to increased intestinal permeability is the translocation of toxic products, predominantly endotoxins/lipopolysaccharide (LPS), from the intestinal tract into the microcirculation. In blood, LPS binds to surface receptors on immune cells initiating an inflammatory response. LPS can also bind to platelets leading to preactivated platelets that have a lower threshold to be aggregated in presence heparin. The aim of this study was to validate a simple, fast and reliable test for screening LPS-loaded platelets. This test named PANDA (acronym for Platelet Number in Different Anticoagulants) consists in the measurement of the mean platelet number in blood samples collected into EDTA and heparin. We analyzed blood samples from 92 patients with gastrointestinal diseases and 23 healthy volunteers and found a markedly low number of platelets in heparinized blood compared to EDTA-anticoagulated blood in patients but not in healthy volunteers. Furthermore, ex vivo addition of endotoxin to blood samples induced a remarkable decrease in platelet count in heparinized blood of the volunteers but not in the patient's group, where platelets could be previously saturated by endotoxin circulating in blood. Platelet should be counted during the first hour after blood collection, in order to avoid false results due to a progressive platelet aggregation in heparinized blood in function of the time. Our results demonstrated that PANDA test can be used for screening LPS-loaded platelets as an indirect diagnostic biomarker for increased intestinal permeability and also for monitoring the gut barrier function during the treatment of gastrointestinal diseases.

A Systematic Review of the Effects of Polyols on Gastrointestinal Health and Irritable Bowel Syndrome

Polyols are sugar alcohols found in certain fruits, vegetables, and sugar-free sweeteners. They make up a component of the diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which is gaining popularity in the treatment of patients with irritable bowel syndrome (IBS). We conducted a systematic review to evaluate the effects of polyols on the gastrointestinal tract in healthy men and women and in patients with IBS. Utilizing PubMed, Ovid, and Embase databases, we conducted a search on individual polyols and each of these terms: fermentation, absorption, motility, permeability, and gastrointestinal symptoms. Standard protocols for a systematic review were followed. We found a total of 1823 eligible articles, 79 of which were included in the review. Overall, available work has shown that polyol malabsorption generally occurs in a dose-dependent fashion in healthy individuals, and malabsorption increases when polyols are ingested in combination. However, studies in patients with IBS have shown conflicting results pertaining to polyol malabsorption. Polyol ingestion can lead to intestinal dysmotility in patients with IBS. Regarding the microbiome, moderate doses of polyols have been shown to shift the microbiome toward an increase in bifidobacteria in healthy individuals and may therefore be beneficial as prebiotics. However, data are limited regarding polyols and the microbiome in patients with IBS. Polyols can induce dose-dependent symptoms of flatulence, abdominal discomfort, and laxative effects when consumed by both healthy volunteers and patients with IBS. Further research is needed to better understand the effects of specific polyols on gastrointestinal function, sensation, and the microbiome in health and gastrointestinal disorders such as IBS.

Methods to determine intestinal permeability and bacterial translocation during liver disease

Liver disease is often times associated with increased intestinal permeability. A disruption of the gut barrier allows microbial products and viable bacteria to translocate from the intestinal lumen to extraintestinal organs. The majority of the venous blood from the intestinal tract is drained into the portal circulation, which is part of the dual hepatic blood supply. The liver is therefore the first organ in the body to encounter not only absorbed nutrients, but also gut-derived bacteria and pathogen associated molecular patterns (PAMPs). Chronic exposure to increased levels of PAMPs has been linked to disease progression during early stages and to infectious complications during late stages of liver disease (cirrhosis). It is therefore important to assess and monitor gut barrier dysfunction during hepatic disease. We review methods to assess intestinal barrier disruption and discuss advantages and disadvantages. We will in particular focus on methods that we have used to measure increased intestinal permeability and bacterial translocation in experimental liver disease models.

ACG clinical guidelines: diagnosis and management of celiac disease

This guideline presents recommendations for the diagnosis and management of patients with celiac disease. Celiac disease is an immune-based reaction to dietary gluten (storage protein for wheat, barley, and rye) that primarily affects the small intestine in those with a genetic predisposition and resolves with exclusion of gluten from the diet. There has been a substantial increase in the prevalence of celiac disease over the last 50 years and an increase in the rate of diagnosis in the last 10 years. Celiac disease can present with many symptoms, including typical gastrointestinal symptoms (e.g., diarrhea, steatorrhea, weight loss, bloating, flatulence, abdominal pain) and also non-gastrointestinal abnormalities (e.g., abnormal liver function tests, iron deficiency anemia, bone disease, skin disorders, and many other protean manifestations). Indeed, many individuals with celiac disease may have no symptoms at all. Celiac disease is usually detected by serologic testing of celiac-specific antibodies. The diagnosis is confirmed by duodenal mucosal biopsies. Both serology and biopsy should be performed on a gluten-containing diet. The treatment for celiac disease is primarily a gluten-free diet (GFD), which requires significant patient education, motivation, and follow-up. Non-responsive celiac disease occurs frequently, particularly in those diagnosed in adulthood. Persistent or recurring symptoms should lead to a review of the patient's original diagnosis to exclude alternative diagnoses, a review of the GFD to ensure there is no obvious gluten contamination, and serologic testing to confirm adherence with the GFD. In addition, evaluation for disorders associated with celiac disease that could cause persistent symptoms, such as microscopic colitis, pancreatic exocrine dysfunction, and complications of celiac disease, such as enteropathy-associated lymphoma or refractory celiac disease, should be entertained. Newer therapeutic modalities are being studied in clinical trials, but are not yet approved for use in practice. Given the incomplete response of many patients to a GFD-free diet as well as the difficulty of adherence to the GFD over the long term, development of new effective therapies for symptom control and reversal of inflammation and organ damage are needed. The prevalence of celiac disease is increasing worldwide and many patients with celiac disease remain undiagnosed, highlighting the need for improved strategies in the future for the optimal detection of patients.

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.

Modern approach for determination of lactulose, mannitol and sucrose in human urine using HPLC-MS/MS for the studies of intestinal and upper digestive tract permeability

A new analytical procedure was described for the simultaneous determination of lactulose, mannitol and sucrose in urine, in which HILIC chromatography and tandem mass spectrometry detection are used. Sugars are orally administered for the estimation of intestinal permeability in children digestive tract. Samples were purified by dispersive solid phase extraction (d-SPE) using Amberlite MB150 resin. Raffinose was selected as an internal standard. The chosen chromatographic separation was carried out on ZIC(®)-HILIC column in 10 min at a flow rate of 0.3 mL/min, using mixture of acetonitrile (ACN) and ammonium acetate (NH(4)Ac) in water (H(2)O) as the mobile phase. Within-run precision (CV) measured at three concentrations was 1.08%, 0.32% and 0.49% for lactulose; 1.88%, 0.47% and 0.75% for mannitol, 2.95%, 1.31% and 0.6% for sucrose. Between-run CVs were 0.75%, 1.1% and 1.2% for lactulose; 1.1%, 1.02% and 1.01% for mannitol; 1.17%, 1.4% and 1.05% for sucrose. Analytical recovery of all three sugar probes was 95.06-99.92%. The detection limits were: 15.94 ng/mL for lactulose, 17.10 ng/mL for sucrose and 11.48 ng/mL for mannitol. The proposed method is rapid, simple, sensitive and suitable for the determination of intestinal permeability of the sugar derivatives in children.

Mechanisms of lipid malabsorption in Cystic Fibrosis: the impact of essential fatty acids deficiency

Transport mechanisms, whereby alimentary lipids are digested and packaged into small emulsion particles that enter intestinal cells to be translocated to the plasma in the form of chylomicrons, are impaired in cystic fibrosis. The purpose of this paper is to focus on defects that are related to intraluminal and intracellular events in this life-limiting genetic disorder. Specific evidence is presented to highlight the relationship between fat malabsorption and essential fatty acid deficiency commonly found in patients with cystic fibrosis that are often related to the genotype. Given the interdependency of pulmonary disease, pancreatic insufficiency and nutritional status, greater attention should be paid to the optimal correction of fat malabsorption and essential fatty acid deficiency in order to improve the quality of life and extend the life span of patients with cystic fibrosis.

Ultrastructural mucosal alterations and increased intestinal permeability in non-celiac, type I diabetic patients

BACKGROUND

Increased intestinal permeability was described in several intestinal auto-immune conditions. There are very few and contradictory reports about type I diabetes mellitus, an auto-immune condition sometimes associated with celiac disease.

AIMS

To investigate intestinal permeability in type I diabetes mellitus patients with no concomitant celiac disease, with a comparison to ultra-structural aspects of duodenal mucosa.

PATIENTS

46 insulin dependent diabetes mellitus, non-celiac, patients (18 females and 28 males, mean age 15.8 +/- 5.3 [S.D.] years) were enrolled. The mean duration of the disease was 5.7 years.

METHODS

The morphological aspect of the small bowel mucosa, at standard light microscopy and electron transmission microscopy, along with intestinal permeability (by lactulose/mannitol test) were studied. Lactulose and mannitol urinary excretion were determined by means of high performance anion exchange chromatography-pulsed amperometric detection.

RESULTS

The lactulose/mannitol ratio was 0.038 [0.005-0.176] (median and range) in 46 patients compared to 0.014 [0.004-0.027] in 23 controls: insulin dependent diabetes mellitus group values being significantly higher than those of the controls (P < 0.0001, Mann-Whitney test). Eight insulin dependent diabetes mellitus patients underwent endoscopy and biopsies were analysed by means of light microscopy and transmission electron microscopy. At the light microscopy level, none of the biopsy samples showed any sign of atrophy nor inflammation, whereas transmission electron microscopy analysis showed remarkable ultra-structural changes in six out of the eight patients. Four parameters were evaluated: height and thickness of microvilli, space between microvilli and thickness of tight junctions.

CONCLUSIONS

This alteration of intestinal barrier function in non-celiac type I diabetes mellitus, frequently associated with mucosal ultra-structural alterations, could suggest that a loss of intestinal barrier function can be a pathogenetic factor in a subset of insulin dependent diabetes mellitus patients.

Lactulose/mannitol test has high efficacy for excluding organic causes of chronic diarrhea

OBJECTIVES

Diagnosis in chronic diarrhea in the absence of a distinctive clinical pattern is often challenging, as biochemical tests prescribed at the first evaluation do not show enough sensitivity and specificity to tailor further investigation. Intestinal permeability to sugars is an accurate test for detecting intestinal damage. The aim of this study was to evaluate the diagnostic value of the lactulose/mannitol (L/M) test in patients with chronic diarrhea.

METHODS

We conducted a prospective cohort study to evaluate the diagnostic value of the L/M test in chronic diarrhea. The test was administered to 261 consecutive patients presenting with three or more bowel movements daily for at least 3 wk. Biochemical tests including complete blood cell count, acute phase reactive proteins, serum albumin and iron, and stool cultures for bacteria, ova, and parasites were assessed at the same time. Additional diagnostic investigations were directed by clinical features as well as first-line test results.

RESULTS

Over 3 yr, 120 (46%) of our patients were found to have an organic cause for chronic diarrhea, whereas in 141 (54%) a functional condition was diagnosed. Multivariate logistic regression analysis revealed that the L/M test and C-reactive protein were independent predictors for the final diagnosis of organic cause of chronic diarrhea, with odds ratios of 1.5 (95% CI = 1.29-1.78) and 5.2 (95% CI = 1.90-14.12), respectively. The area under the receiver operating characteristic (ROC) curve of the adjusted model was 0.82, with positive predictive value of 80.4% and negative predictive value of 77.7%.

CONCLUSIONS

The L/M test is a powerful tool for workup in patients with chronic diarrhea. Introducing the L/M test as first-level test effectively improves the selection of patients who need further evaluation.

Assessment of hypolactasia and site-specific intestinal permeability by differential sugar absorption of raffinose, lactose, sucrose and mannitol

The sugar absorption test is a non-invasive test for investigating intestinal permeability by simultaneous measurement of four probe sugars. In this study, we evaluated the utility of raffinose, lactose, sucrose and mannitol as probe sugars and calculated their urinary recovery as a percentage of ingested dose (mol/mol) and the recovery ratios of raffinose/mannitol, lactose/ raffinose and sucrose/raffinose. The reference ranges for these ratios, established from 39 healthy volunteers, are 0.005-0.015, 0.13-0.63 and 0.09-0.47, respectively. This sugar absorption test was performed in three patient groups. i) In 109 patients with aspecific gastrointestinal symptoms of whom intestinal histology was studied by duodenal biopsies: the urinary raffinose/mannitol recovery ratio highly correlated with gradation of duodenal damage; the sensitivity and specificity of the raffinose/mannitol ratio for detection of intestinal damage were 93% and 91%, respectively, using a cut-off level of 0.020. ii) In 70 patients in whom intestinal lactase activity was investigated by the lactose tolerance test: the urinary lactose/raffinose recovery ratio provided high diagnostic accuracy for hypolactasia (sensitivity 81% and specificity 89% at a cut-off level of 0.70). In analogy with the lactose/raffinose ratio, we suppose that the sucrose/raffinose ratio can be used as a marker of hyposucrasia. iii) In 40 patients with localized small intestinal damage, Crohn's disease of the ileum (n = 21) and celiac disease with histologically proven duodenal damage (n = 19): the raffinose/mannitol recovery ratio was increased in 100% of patients with celiac disease and in 81% of patients with Crohn's disease; increased lactose/raffinose recovery ratio (hypolactasia) and increased sucrose/raffinose (hyposucrasia) were present in 89% and 95% of celiac patients and 19% and 0% of Crohn's disease patients, respectively. The combination of the raffinose/mannitol ratio and sucrose/raffinose ratio appears to be an indication of the distribution of intestinal damage.

Assessment of intestinal permeability and orocecal transit time in patients with systemic sclerosis: analysis of relationships with epidemiologic and clinical parameters

OBJECTIVE

The aim of this study was to assess intestinal permeability (IP) in patients with systemic sclerosis (SSc) and to relate the results with general disease activity and gastrointestinal involvement.

METHODS

Twenty-eight females and four males were studied. Patients with severe gastrointestinal involvement were excluded. Thirty-three healthy volunteers served as controls. Intestinal permeability was assessed by means of the orally administered cellobiose/mannitol sugar (Ce/Ma) test. Intestinal transit time (ITT) was investigated with the H2-lactulose breath test.

RESULTS

The mean value of IP in 32 SSc patients was significantly higher than in 33 controls ( P<0.05), although it fell within the normal range. Eleven patients showed abnormally high individual IP values (>0.028) that significantly correlated to disease duration ( r=0.73). Altered IP was associated with the higher but not statistically relevant presence of anti-Scl70 antibodies (9/11) and to more severe gastrointestinal involvement. More than half of the SSc patients showed slower orocecal transit times on the H2 breath test. In particular, delayed ITT was observed in 60% of patients with increased IP and in all patients with moderate gastrointestinal involvement according to the scleroderma severity scale.

CONCLUSION

Intestinal permeability was altered in 11/32 SSc patients. Correlations between increased IP and duration of disease and degree of gastrointestinal involvement appear to support the hypothesis of secondary involvement of the intestinal barrier, and the presence of anti-Scl70 antibodies in 82% of the patients with higher IP clearly reinforces the hypothesis of an altered immune response in these subjects.

Assessment of intestinal permeability: enzymatic determination of urinary mannitol, raffinose, sucrose and lactose on Hitachi analyzer

The sugar absorption test is the usual test for measurement of intestinal permeability. After intestinal absorption of probe sugars the subsequently excreted sugars are measured in urine. We have developed four enzymatic methods for the measurement of the urinary concentration of the probe sugars mannitol, raffinose, lactose and sucrose. Mannitol, lactose and sucrose are directly measured on Hitachi 917 using mannitol dehydrogenase, beta-galactosidase and invertase, respectively, as enzyme reagents. Raffinose measurement needs a three hours preincubation with alpha-galactosidase, after which the liberated sucrose is measured. The analytical performances such as within- and between-run precision, linearity, lowest detection limit, interference of other sugars and comparison with a gas chromatographic method are described for the four methods. These methods are accurate an can easily be performed in any clinical laboratory.

Introduction: a welcome to the First Special Animal Health Issue of AAPS PharmSci

The goal of this special volume is to provide veterinary scientists with state-of-the art reviews in animal health and to inform human health scientists of the various challenges and collaborative opportunities associated with their animal health counterparts. The contributors are highly respected experts, providing invaluable insights into current issues and state-of-the-art advances within veterinary medicine.

Quantitation of intraepithelial lymphocytes in human duodenum: what is normal?

BACKGROUND

An increase in intraepithelial lymphocytes (IELs) is mandatory for the histological diagnosis of coeliac disease (CD). Currently, duodenal biopsies are used almost exclusively to establish the diagnosis, yet published work continues to cite an upper limit of 40 lymphocytes/100 epithelial cells, a figure derived from jejunal biopsies over 30 years ago.

AIM

To establish the normal range for IEL counts in distal duodenal biopsies.

MATERIALS/METHODS

Twenty subjects (seven men, 13 women; median age, 34 years; range, 20-65) with a normal sugar permeability test and concurrent distal duodenal biopsies were identified. The number of IELs and epithelial cell nuclei in an uninterrupted length of surface (villous) epithelium (> 500 cells) was counted. An image analysis system was used to assess villous architecture by calculating the villous height to crypt depth ratio.

RESULTS

The range of IEL counts in 20 subjects was 1.8-26/100 villous epithelial cells, with a mean value of 11 and SD of 6.8. The mean villous to crypt ratio was 1.82 (SD, 0.38; range, 1.22-2.46). There was no correlation between IEL counts and villous to crypt ratio (Spearman rank correlation, -0.066; p = 0.80).

CONCLUSIONS

These results suggest that 25 IELs/100 epithelial cells (mean +2 SD) should be taken as the upper limit of the normal range for duodenal mucosa.

Intestinal permeation and gastrointestinal disease

The gastrointestinal tract constitutes one of the largest sites of exposure to the outside environment. The function of the gastrointestinal tract in monitoring and sealing the host interior from intruders is called the gut barrier. A variety of specific and nonspecific mechanisms are in operation to establish the host barrier; these include luminal mechanisms and digestive enzymes, the epithelial cells together with tight junctions in between them, and the gut immune system. Disruptions in the gut barrier follow injury from various causes including nonsteroidal anti-inflammatory drugs and oxidant stress, and involve mechanisms such as adenosine triphosphate depletion and damage to epithelial cell cytoskeletons that regulate tight junctions. Ample evidence links gut barrier dysfunction to multiorgan system failure in sepsis and immune dysregulation. Additionally, contribution of gut barrier dysfunction to gastrointestinal disease is an evolving concept and is the focus of this review. An overview of the evidence for the role of gut barrier dysfunction in disorders such as Crohn's disease, celiac disease, food allergy, acute pancreatitis, non-alcoholic fatty liver disease, and alcoholic liver disease is provided, together with critical insight into the implications of this evidence as a primary disease mechanism.

Intestinal permeability in Crohn's disease patients and their first degree relatives

BACKGROUND

Family studies suggested that an altered intestinal permeability plays a role in the genesis of Crohn's disease.

AIM

Aim of the present study was to investigate a possible genetic alteration of the mucosal barrier in Crohn's disease.

SUBJECTS

16 Crohn's disease patients and 26 of their cohabiting first degree relatives were studied.

METHODS

To investigate intestinal permeability, Cellobiose/Mannitol test was administered to both groups.

RESULTS

In the two groups, we found that the median intestinal permeability values were higher and statistically different from those obtained in 32 healthy control subjects as well as in five healthy control families. Six (37.5%) Crohn's disease patients and three (11.5%) of their first degree relatives showed increased individual intestinal permeability values. Intestinal permeability alteration in Crohn's disease patients was unrelated to sex, age, disease activity, localisation, duration, treatment schedule, as well as to serum anti-Saccharomyces cervisiae antibody positivity in a pilot study conducted in 7 Crohn's disease patients; anti-Saccharomyces cervisiae antibody values were negative in all 10 first degree relatives investigated.

CONCLUSIONS

These findings demonstrate the increase in IP in 37% of the patients and in 11% of their relatives. More extensive investigation of the correlation between ASCA alterations and IP will be needed in both patients with Crohn's disease and their relatives.

Effect of chemotherapy with 5-fluorouracil on intestinal permeability and absorption in patients with advanced colorectal cancer

5-Fluorouracil (5-FU), in association with leucovorin (LV), is the most used chemotherapy agent in the treatment of colorectal cancer. Response rate, as well as side-effect incidence, increases with the dose intensity of regimens that are used. The most common dose-limiting toxicity for 5-FU/LV modulation is diarrhea. To assess the modification of small intestinal function, we investigated the changes in intestinal permeability (IP) and intestinal absorption (IA) in 41 chemo-naive patients (21 men and 22 women; mean age, 61 +/- 9 years) with advanced colorectal cancer after treatment with the association of folinic acid and 5-FU. After chemotherapy administration, we found a marked increase in IP and a reduction in IA, measured as cellobiose-mannitol (CE-MA) ratio (p < 0.0001) and D-xylose absorption (p = 0.0001), respectively. Patients who experienced diarrhea have an increase in CE-MA ratio and a reduction in D-xylose absorption values, both statistically significant. Cellobiose-mannitol ratio and D-xylose absorption tests can be used for the assessment of toxic effect of 5-FU on mature intestinal epithelium and also for evaluating the role of cytoprotective agents.

Oral glutamine in the prevention of fluorouracil induced intestinal toxicity: a double blind, placebo controlled, randomised trial

BACKGROUND

5-Fluorouracil (FU) in association with folinic acid (FA) is the most frequently used chemotherapeutic agent in colorectal cancer but it often causes diarrhoea. Animal and human studies suggest that glutamine stimulates intestinal mucosal growth.

AIM

To determine if oral glutamine prevents changes in intestinal absorption (IA) and permeability (IP) induced by FU/FA.

METHODS

Seventy chemotherapy naive patients with colorectal cancer were randomly assigned to oral glutamine (18 g/day) or placebo before the first cycle of FU (450 mg/m(2)) and FA (100 mg/m(2)) administered intravenously for five days. Treatment was continued for 15 days, starting five days before the beginning of chemotherapy. IA (D-xylose urinary excretion) and IP (cellobiose-mannitol test) were assessed at baseline and four and five days after the end of the first cycle of chemotherapy, respectively. Patients kept a daily record of diarrhoea, scored using the classification system of the National Cancer Institute (Bethesda, Maryland, USA). Duration of diarrhoea was recorded and the area under the curve (AUC) was calculated for each patient.

RESULTS

Baseline patient characteristics and basal values of IP and IA tests were similar in the two arms. After one cycle of chemotherapy, the reduction in IA (D-xylose absorption) was more marked in the placebo arm (7.1% v 3. 8%; p=0.02); reduction of IP to mannitol was higher in the placebo arm (9.2% v 4.5%; p=0.02); and urinary recovery of cellobiose was not different between the study arms (p=0.60). Accordingly, the cellobiose-mannitol ratio increased more in the placebo arm (0.037 v 0.012; p=0.04). Average AUC of diarrhoea (1.9 v 4.5; p=0.09) and average number of loperamide tablets taken (0.4 v 2.6; p=0.002) were reduced in the glutamine arm.

CONCLUSIONS

Glutamine reduces changes in IA and IP induced by FU and may have a protective effect on FU induced diarrhoea.

Lactulose-mannitol intestinal permeability test: a useful screening test for adult coeliac disease

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

Altered intestinal permeability to mannitol in diabetes mellitus type I

BACKGROUND

Intestinal permeability has seldom been investigated in diabetes mellitus, even though patients frequently report gastrointestinal symptoms, and it has recently been shown that the prevalence of celiac disease associated with diabetes mellitus is higher than expected.

METHODS

Intestinal permeability to cellobiose and mannitol was investigated in 31 patients affected by type I uncomplicated diabetes mellitus. Values were compared with those obtained in 32 normal subjects.

RESULTS

The percentage of mannitol recovery was far higher than normal in two thirds of the investigated patients and correlated with the length of disease, even though the probes' ratio (cellobiose/mannitol) was in the normal range.

CONCLUSIONS

A not previously reported increase of intestinal permeability to mannitol, clear-cut and not associated with that of the larger probe, is found in type I uncomplicated diabetes mellitus. These results may describe a primary feature of type I diabetes mellitus and the initial steps of evolution to celiac disease.

Measurement of small intestinal permeability markers, lactulose, and mannitol in serum: results in celiac disease

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

A double-blind placebo-controlled pilot study of glutamine therapy for abnormal intestinal permeability in patients with AIDS

OBJECTIVES

Up to 20% of patients with AIDS have abnormal intestinal permeability (IP). Glutamine seems to play an important role in preventing the increase in IP and loss of intestinal mucosal mass associated with total parenteral nutrition, and may be superior to glucose for oral rehydration in the setting of intestinal infection. This study was designed to see if supplemental glutamine could alter the abnormal IP of AIDS.

METHODS

Randomly chosen patients with AIDS from the Jacobi Medical Center human immunodeficiency virus (HIV) clinic underwent IP testing using lactulose and mannitol. Those with abnormal IP were enrolled. Duodenal biopsies were performed with a Crosby capsule and the patients were randomized in a double-blind fashion to receive placebo or glutamine (4 g/day or 8 g/day) for 28 days, after which intestinal permeability tests and duodenal biopsies were repeated. Intestinal morphology was graded by ratio of villus height to crypt depth, and by degree of inflammation.

RESULTS

All patients complied with the therapy and there were no dropouts or reported side effects. The results showed less worsening of IP with the 4 g/day dose, compared with placebo. At the 8 g/day dose, there was stabilization of IP and improved absorption of mannitol. Intestinal morphology and inflammation did not change in any group.

CONCLUSIONS

These results, although not significant, suggest a trend towards improved IP and enhanced intestinal absorption with glutamine. Glutamine doses of at least 20 g/day may be necessary to improve IP. We recommend further studies at higher doses and for longer durations.

Gastrointestinal permeability and absorptive capacity in sepsis

OBJECTIVE

To assess gastrointestinal permeability and functional absorptive capacity in patients with sepsis.

DESIGN

Case control study to analyze gastrointestinal permeability and functional absorptive capacity of septic patients by differential saccharide absorption (from an oral test solution) and excretion.

SETTING

The intensive Therapy Unit of St. Thomas' Hospital, London, UK.

PATIENTS

Twenty patients with a mean Acute Physiology and Chronic Health Evaluation (APACHE) II score of 18.4 who were admitted to the intensive care unit with a diagnosis of sepsis. All patients were on enteral feeding. Patients with abdominal pathology were excluded.

INTERVENTIONS

An oral test solution containing 5 g of lactulose, 1 g of L-rhamnose, 0.5 g of D-xylose, and 0.2 g of 3-O-methyl-D-glucose dissolved in water to a final volume of 100 mL was administered to patients and controls. Urine was collected for 5 hrs starting immediately after administration of the test solution and the saccharide content of the urine was estimated and expressed as a percentage recovery of the oral test solution.

MEASUREMENTS AND MAIN RESULTS

Septic patients had increased lactulose/L-rhamnose urine excretion ratios (0.23 +/- 0.19) compared with control subjects (0.03 +/- 0.01, p < .001), consistent with increased gastrointestinal permeability in sepsis. Septic patients had decreased L-rhamnose/3-O-methyl-D-glucose urine excretion ratios (0.14 +/- 0.07) compared with normal controls (0.28 +/- 0.08, p < .001), consistent with decreased gastrointestinal functional absorptive capacity in sepsis.

CONCLUSIONS

Patients with acute sepsis exhibit increased gastrointestinal permeability and decreased gastrointestinal functional absorptive capacity in comparison with healthy control subjects. These abnormalities may contribute to the pathophysiology of sepsis.

Gluten-sensitive enteropathy

Gluten-sensitive enteropathy is induced by dietary wheat gliadin and related proteins in genetically susceptible individuals. Most evidence suggests that the mucosal lesion represents an immunologically mediated injury triggered by gluten in the context of a particular assortment of major histocompatibility complex genes. The amino acid residues of gliadin and related proteins responsible for toxicity have not been identified; in vitro systems are available, but definitive conclusions must rely on in vivo jejunal challenges. At a conservative estimate, symptomatic gluten-sensitive enteropathy affects approximately 1 in 1000 individuals in Europe; however, it is now becoming clear that a greater proportion of individuals has clinically silent disease, and probably many others have a minor form of the the enteropathy. In most countries, the clinical presentation has changed over the past few years coming closer to the adult type of the disease, and the age of onset of symptoms is shifting upward. Liver, joint, hematologic, dental, and neurologic symptoms are increasingly being recognized. Several diseases are associated the gluten-sensitive enteropathy, such as IgA deficiency, insulin-dependent diabetes mellitus, and a range of other autoimmune diseases. Tests based on the measurement of antigliadin and antiendomysium antibodies have gained success as noninvasive screening tests; however, the ultimate diagnosis still is based on the finding of a severe histologic lesion of the jejunum while the patient is on a gluten-containing diet and on its disappearance once the gluten is excluded from the diet. A lifelong, strict GFD is mandatory for celiac children. Among other long-term problems, an increased risk of intestinal lymphoma has been reported in patients on a normal gluten-containing diet.

Intestinal permeability and orocaecal transit time in elderly patients with Parkinson's disease

The aetiology of weight loss in patients with Parkinson's disease is likely to be multifactorial. We studied 15 patients with Parkinson's disease and 15 age- and sex-matched controls and looked for evidence of malabsorption due to small bowel bacterial overgrowth or alteration of intestinal permeability. There was a marked increase in orocaecal transit time in the patients with Parkinson's disease, although lactulose hydrogen breath testing did not show evidence of small bowel bacterial contamination. Intestinal permeability measured by the differential sugar absorption test was also deranged. There was reduced absorption of mannitol in patients with Parkinson's disease while lactulose absorption was similar in both groups, suggesting decreased non-mediated uptake across the enterocyte brush border membrane in patients with Parkinson's disease.

Lymphocytic gastritis and associated small bowel disease: a diffuse lymphocytic gastroenteropathy?

AIM

To investigate the natural history of lymphocytic gastritis (LG) and its relation to Helicobacter pylori infection and to coeliac disease using serology, duodenal biopsy and a small intestinal permeability test.

METHOD

Twenty two patients diagnosed as having LG between 1984 and 1994 were investigated by upper gastrointestinal endoscopy at which gastric and duodenal biopsy specimens were taken for histological assessment and immunohistology. Serum was collected for measurement of anti-H pylori, anti-gliadin and anti-endomysial antibodies. A lactulose/mannitol absorption test was performed within one week of endoscopy. Control groups were studied by histology, serology and permeability tests.

RESULTS

Three patients had been recently diagnosed as having LG while 15 still had the condition after a mean of 13.9 (range two to 38) months. LG involved the antrum alone in three patients, antrum and body in seven, body alone in six, and gastric remnant in two. Gastroduodenal intraepithelial lymphocytes (IELs) were T cells and predominantly of T suppressor (CD8) type. Duodenal IELs were increased compared to age/sex matched controls with chronic gastritis. Four patients had duodenal villous atrophy. Four patients no longer had LG after a mean of 29.3 (10-70) months but had increased gastroduodenal IELs. H pylori was present in four (22%) of 18 patients with LG but H pylori serology was positive in 11 (61%) of 18. There was no difference in seropositivity when compared with age/sex matched controls with dyspepsia. Eleven of 20 patients with LG tested had abnormal lactulose/mannitol absorption (v none of 22 controls with chronic gastritis). Four patients with LG, all with villous atrophy, were seropositive for IgA endomysial antibody.

CONCLUSIONS

The persistence of LG with time, the association with increased duodenal IELs and abnormal small intestinal permeability suggests LG may be a manifestation of a diffuse lymphocytic gastroenteropathy related to sensitivity to gluten or some other agent.

Coeliac disease in adults

Coeliac disease is a chronic disease characterized by small bowel villous atrophy which impairs nutrient absorption and improves on withdrawal of wheat gliadins and barley, rye and oat prolamins from the diet. Knowledge of the adult form of coeliac disease has greatly improved in recent years. Although this knowledge is not yet sufficiently widespread among referring clinicians, it has, over the past few years, allowed an increasing number of patients to be diagnosed with subclinical forms characterized by minor, transient or apparently unrelated symptoms. As a consequence, our views on the clinical and epidemiological aspects of this condition, the prevalence of which in the general population is believed to be close to 1 in 300, have changed and are still changing. Since it has been demonstrated that a strict gluten-free diet is protective against the complications of adult coeliac disease, it is important that even subclinical and silent forms are diagnosed and treated as early as possible. Non-invasive screening tests, such as anti-gliadin and anti-endomysium antibody estimation, should therefore be used systematically in groups considered to be at risk of coeliac disease. These include first-degree relatives of coeliac patients and patients with insulin-dependent diabetes mellitus, iron-deficiency anaemia, epilepsy with cerebral calcification, recurrent aphthous stomatitis and dental enamel hypoplasia. Other conditions will probably be identified in the near future.

Differential in vivo and in vitro intestinal permeability to lactulose and mannitol in animals and humans: a hypothesis

BACKGROUND/AIMS

Clinical interpretation of urinary recovery ratios of lactulose and mannitol is hampered by incomplete understanding of the mechanisms of transmucosal passage. The aim of this study was to compare in vivo and in vitro probe permeability.

METHODS

Stripped sheets of small intestine from rodents and human biopsy specimens were mounted in Ussing chambers, and mucosa-to-serosa fluxes of lactulose and mannitol were determined. Urinary recovery of orally applied probes was measured in rodents, cats, and humans.

RESULTS

In vitro lactulose/mannitol flux ratios were close to 0.8 in all species. Urinary recovery ratios differed between rodents and cats or humans; low ratios in cats and humans were due to high mannitol recovery.

CONCLUSIONS

Interspecies variation in urinary recovery of mannitol is caused by differences specific for the intact small intestines in vivo. Because hyperosmolality of villus tips in vivo varies, being highest in humans and cats as a result of vascular countercurrent multiplication, it is hypothesized that the high urinary recovery of mannitol in these species is caused by solvent drag through pores that allow the passage of mannitol but not of lactulose. Therefore, the lactulose/mannitol ratio is primarily a standard for the normal functioning of villus epithelial cells in metabolite absorption and for normal villus blood flow.

Intestinal permeability measurements - a new application for water soluble contrast media?

The detection and quantification of altered intestinal barrier function (intestinal permeability) have been addressed frequently during the last year, but the tests available for determination of intestinal permeability are both flawed and have limitations. The new water-soluble roentgen contrast media (CM) of low- and iso-osmolar type have been proposed as intestinal permeability probes. In this article this possible new application for water-soluble CM is discussed in terms of their inherent properties and the experimental and clinical results obtained so far. The 2 iso-osmolar dimers, iodixanol (Visipaque) and iotrolan (Isovist), seem to be as good as the well-documented radio-labeled permeability probe (51)Cr-EDTA in detecting injury of the intestinal mucosal barrier. The CM offer the advantage of allowing direct control of bowel wall exposure with the aid of fluoroscopy. Current permeability probes lack this quality. Iodine-containing substances may be analyzed by the rapid, simple and reliable X-ray fluorescence technique, which is suitable for application in routine clinical practice. We conclude that the new water-soluble roentgen CM have properties which may be of use in the diagnosis and quantification of altered intestinal barrier function.

Uptake of antigens: role in gastrointestinal disease

The intestine is exposed to a wide variety of macromolecules. Because macromolecules are antigenic, mechanisms have evolved in the gastrointestinal tract to regulate their absorption. Macromolecular uptake can be beneficial in delivering essential factors for growth and in sampling the antigenic milieu of the gastrointestinal tract. Specific transport mechanisms exist to execute this physiological absorption. However, inappropriate and uncontrolled antigen transport may occur in disease states, or as a prelude to disease states in the gastrointestinal tract. Such transport may result in immune responses that are harmful. In this review we examine both physiological transport of macromolecules through epithelia and through M cells. We also discuss uncontrolled transport and its relation to disease states. We conclude by examining the interrelationship between antigen transport and an altered immune system in the establishment of gastrointestinal disease.

Immunologic and intestinal permeability tests as predictors of relapse during gluten challenge in childhood coeliac disease

Fifteen children with an initial diagnosis of coeliac disease underwent gluten challenge either because they had never had a jejunal biopsy or because they had had one during the first 2 years of life. The challenge was preceded by a biopsy; clinical symptoms, the cellobiose/mannitol permeability test, and gliadin and endomysial antibody measurement were used to determine the timing of the confirmatory biopsy: it was performed if one test result was repeatedly abnormal or two results were concomitantly abnormal. Gliadin antibodies increased early (already 7 days after the reintroduction of gluten to the diet), but in many cases they returned to normal values thereafter. Increased intestinal permeability to sugars and even more positivity of endomysial antibody were good predictors of histologic relapse. The sequential use of laboratory tests during gluten challenge may significantly shorten its duration.

Intestinal permeability and function in patients infected with human immunodeficiency virus. A comparison with coeliac disease

The relationships among intestinal permeability, advancing human immunodeficiency virus (HIV) infection, and the presence of diarrhoea or weight loss were investigated in 51 HIV patients and 20 healthy controls. Ten patients with untreated coeliac disease were also investigated for comparison. Fasting subjects drank an isosmolar test solution containing D-xylose, lactulose (LL), L-rhamnose (R) and 3-O-methyl-D-glucose. Urine was collected for 5 h, test sugar content being subsequently measured by thin-layer chromatography for the dosing sugars. Intestinal permeability (LL/R excretion ratio) and recovery of D-xylose and 3-O-methyl-D-glucose in urine were abnormal in patients with HIV disease, and especially those with diarrhoea, as they were in coeliac disease. Patients with coeliac disease and HIV disease, especially when diarrhoea and/or weight loss were present, had significantly reduced 5-h excretion of L-rhamnose, D-xylose, and 3-O-methyl-D-glucose. These data indicate that abnormal permeability and reduced intestinal absorption capacity are common in HIV patients, occur at all stages of HIV disease, especially in the presence of diarrhoea, and, with the exception of lactulose permeation, are relatively similar to the alterations seen in coeliac disease.

Analysis of multiple sugar probes in urine and plasma by high-performance anion-exchange chromatography with pulsed electrochemical detection. Application in the assessment of intestinal permeability in human immunodeficiency virus infection

Mannitol, 3-O-methylglucose and lactulose administered orally are used to investigate small intestinal absorption pathways and mucosal integrity. Current methods of analysis include thin-layer chromatography, gas chromatography (GC) and enzymatic analysis, which require separate estimation of mono- and disaccharides and for GC, prior derivatization. We describe a high-pressure anion-exchange chromatographic method coupled with pulsed electrochemical detection allowing simultaneous measurement of all three sugars and its clinical application in monitoring intestinal damage in human immunodeficiency virus (HIV) infection. Sample preparation is simple and fast. All sugars are resolved within 10 min. Mean recovery is 93.3% for all sugars and the overall relative standard deviation is 4.2%. Intestinal permeability (lactulose/mannitol ratio) rises with disease progression to AIDS, indicating mucosal damage. The greatest increase in permeability is associated with chronic diarrhoea. The method is an ideal non-invasive test to assess gut mucosal damage in HIV infection.

Is an intestinal permeability test a valid marker for slight dietary transgressions in adolescents with coeliac disease?

Adolescents with coeliac disease often fail to adhere to a strict gluten free diet. The effectiveness of intestinal permeability to sugars as a marker of slight dietary transgressions by such adolescents was assessed. Severe dietary transgressions were excluded from the study. Subjects were divided into two groups according to whether they committed slight dietary transgressions or adhered to a strict gluten free diet. A reference group of preadolescents with coeliac disease was also included in the study. Intestinal permeability and antigliadin antibody tests were performed on all patients. The diagnostic marker of intestinal permeability was excellent in the reference group. Neither the intestinal permeability test nor antigliadin antibody tests, however, succeeded in discriminating between the two groups of adolescents considered in this study. In conclusion the intestinal permeability test is not a valid marker for slight dietary transgression in such patients.

Intestinal permeability in patients with coeliac disease and relatives of patients with coeliac disease

The functional integrity of the small bowel is impaired in coeliac disease. Intestinal permeability, as measured by the sugar absorption test probably reflects this phenomenon. In the sugar absorption test a solution of lactulose and mannitol was given to the fasting patient and the lactulose/mannitol ratio measured in urine collected over a period of five hours. The sugar absorption test was performed in nine patients with coeliac disease with an abnormal jejunum on histological examination, 10 relatives of patients with coeliac disease with aspecific symptoms but no villous atrophy, six patients with aspecific gastrointestinal symptoms but no villous atrophy, and 22 healthy controls to determine whether functional integrity is different in these groups. The lactulose/mannitol ratio (mean (SEM) is significantly higher in both coeliac disease (0.243 (0.034), p < 0.0001)) and relatives of patients with coeliac disease (0.158 (0.040), p < 0.005)) v both healthy controls (0.043 (0.006)) and patients with aspecific gastrointestinal symptoms (0.040 (0.011)). The lactulose/mannitol ratio in relatives of coeliac disease patients was significantly lower than in the coeliac disease patient group (p = 0.04). The lactulose/mannitol ratio was the same in healthy controls and patients with aspecific gastrointestinal symptoms. It is concluded that the sugar absorption test is a sensitive test that distinguishes between patients with coeliac disease and healthy controls. The explanation for the increased permeability in relatives of patients with coeliac disease is uncertain. Increased intestinal permeability may be related to constitutional factors in people susceptible to coeliac disease and may detect latent coeliac disease. The sugar absorption test may therefore be helpful in family studies of coeliac disease.

Uptake and transport of macromolecules by the intestine: possible role in clinical disorders (an update)

The intestine is exposed to a wide variety of macromolecules. Because macromolecules are antigenic, mechanisms have evolved in the gastrointestinal tract to regulate their absorption. Macromolecular uptake can be beneficial in delivering essential factors for growth and in sampling the antigenic milieu of the gastrointestinal tract. Specific transport mechanisms exist to execute this physiological absorption. However, inappropriate and uncontrolled antigen transport may occur in disease states or as a prelude to disease states in the gastrointestinal tract. Such transport may result in immune responses that are harmful. This review examines physiological transport of macromolecules through epithelia and through M cells. It also considers uncontrolled transport and its relation to disease states. The review concludes with an examination of the interrelationship between antigen transport and an altered immune system in the establishment of gastrointestinal disease.

Celiac Disease and Dermatitis Herpetiformis: National survey indicates delays in diagnosis

A national survey of 1937 members of the Canadian Celiac Association was conducted by mail questionnaire in June 1989 to study problems in diagnosing and managing celiac disease (CD) and dermatitis herpetiformis. Although 82% of the 1294 respondents were biopsied, 14% were diagnosed by their dramatic response to the gluten-free diet. Fifteen percent of biopsy-proven respondents saw five or more doctors before CD was diagnosed. Mean delays in diagnosis ranged from 5.8 (±10.9) years for those with nausea or vomiting to 13.9 (±14.5) years for those with headache or migraine.

Experimental colonic inflammation and ulceration. Permeation of a water-soluble contrast medium as a measure of 'disease' activity

The aim of this study was to investigate the permeation of an isosmolar water-soluble X-ray contrast medium (CM) from the unperforated colon after experimental induction of inflammation and ulceration. One hundred and sixty-five male rats were included. In 110 rats 0.25 ml of 40% ethanol + 15 mg or 30 mg trinitrobenzene (TNB) was instilled into the colon, 7-9 cm proximal to the anus, inducing different degrees of inflammation. Fifty-five rats served as controls and had 0.25 ml saline instilled with the same procedure. At 7, 14, 21, and 28 days 3 ml of the non-ionic CM iodixanol was applied as an enema, and subsequently all urine was collected for the next 4 h. High-performance liquid chromatography analyses of the urine showed a positive relation between the severity of inflammation/ulceration in the colonic wall as assessed by a macroscopic damage score and the amount of CM excreted in the urine. Water-soluble contrast media may have prospects of combining functional tests of intestinal membrane dysfunction with segmental exposure control.

Antigliadin antibody, D-xylose, and cellobiose/mannitol permeability tests as indicators of mucosal damage in children with coeliac disease

A dual sugar (cellobiose/mannitol) permeability test using an iso-osmolar solution was performed, to compare its ability to predict small-bowel mucosal damage in children affected by coeliac disease with the determination of serum levels of D-xylose and antigliadin antibody. Eighty-three children (67 on gluten-containing diet and 16 on gluten-free diet) were investigated. The D-xylose and the serum antigliadin antibody test predicted accurately 70% and 78% of the small-bowel biopsy results, respectively, whereas the cellobiose-mannitol permeability test predicted 93%. These data confirm the superiority of the permeability test over the D-xylose test, although the former cannot be advocated as a substitute for jejunal biopsy. Our results suggest a complementary use of the permeability test and the antigliadin antibody measurement as screening tests for coeliac disease before applying more invasive procedures.

A reliable screening test for coeliac disease: enzyme-linked immunosorbent assay to detect anti-gliadin antibodies in serum

A simple, rapid, highly reproducible enzyme-linked immunosorbent assay detecting anti-gliadin antibodies in serum to screen for coeliac disease (CD) is described. By combining the results of anti-gliadin IgA and IgG determinations the overall sensitivity of the assay was found to be 100% and the specificity 96% for children and 99% for adults. Significantly elevated antigliadin IgA and IgG antibodies were detected in all 20 children and all 25 adults with untreated CD. False positive results were found in 1/79 histologically normal control and 5/86 disease control children, while for adults false positive rates were 0/74 and 1/34 for the healthy and disease control groups, respectively. Anti-gliadin IgA and IgG was measured in serum samples from 52 coeliac patients (11 children and 41 adults) treated with a gluten-free diet (GFD). Each of the children and 28 of the adults who followed a strict GFD had significantly lower IgA and IgG levels than untreated CD patients. The serum anti-gliadin IgA and IgG levels of the 13 adults not complying with a GFD were similar to those found for untreated CD patients. This assay is recommended as a screening test for CD as well as a tool for follow-up of treated patients.

Activation of mast cells by bile acids

To test whether bile acids interact with mast cells, dilute, aqueous solutions of five pure unconjugated natural bile acids and their corresponding glycine or taurine conjugates were incubated with murine PT-18 cells (a mast cell line functionally and cytochemically similar to mucosal mast cells) or with freshly isolated rat peritoneal mast cells. Bile acid solutions ranged in concentration from 0.3 to 10 mmol/L; histamine release was assessed by a fluorimetric assay, and cell lysis by cytosolic enzyme (lactate dehydrogenase) release. Lipophilic, dihydroxy bile acids (chenodeoxycholic acid and deoxycholic acid as well as their glycine and taurine conjugates) caused histamine release in a dose-related manner; cholic acid and its conjugates caused much less or no histamine release. Two hydrophilic bile acids (ursodeoxycholic acid and ursocholic acid and their conjugates) were virtually devoid of activity. Histamine release, which was independent of extracellular Ca2+, occurred at 0.3 mmol/L, well below the critical micellization concentration. For a given concentration, unconjugated bile acids and glycine-conjugated bile acids induced more histamine release than taurine-conjugated bile acids; maximal release was observed at 3 mmol/L for lipophilic, dihydroxy bile acids. To test whether bile acids could also cause histamine release from cutaneous mast cells in vivo, rats were injected intradermally with bile acid solutions and histamine release assessed by capillary leakage of Evan's blue dye. Cutaneous blueing was greater with cytotoxic bile acids, chenodeoxycholyglycine or deoxycholylglycine, than with ursodeoxycholylglycine and was inhibited by prior antihistamine treatment. Histamine release correlated highly and positively with lipophilicity and with bile acid surface activity. It was concluded that lipophilic but not hydrophilic bile acids possess concentration-dependent cytotoxicity toward mast cells causing histamine release, that unconjugated and glycine-conjugated bile acids are more potent than taurine-conjugated bile acids, and that mast cell histamine release is highly correlated with lipophilicity of bile acids as well as their surface activity.

Abnormal permeability precedes the development of a gluten sensitive enteropathy in Irish setter dogs

Intestinal permeability to 51Cr-EDTA was examined during the development of gluten sensitive enteropathy in dogs bred from affected Irish setters and reared on a normal wheat containing diet. Comparisons were made with litter mates reared on a gluten free diet and with a control group of age matched, clinically healthy Irish setters reared on the normal diet. Studies at 4, 6, 8, and 12 months of age were correlated with morphometric and biochemical examinations of peroral jejunal biopsy specimens. Permeability was increased at all ages in the group fed gluten free diet compared with control dogs, although there were no differences in villus height, intraepithelial lymphocyte density, and alkaline phosphatase activity. At four months, permeability in the normal diet group was greater than in controls, although comparable with that in the gluten free diet group. Permeability in the normal diet group increased further in conjunction with the development of partial villus atrophy and reduced alkaline phosphatase activity, and by 12 months permeability was significantly greater than in their gluten free diet litter mates and the control dogs. The findings suggest that an underlying permeability abnormality may be involved in the pathogenesis of gluten sensitive enteropathy in Irish setter dogs.

Rapid enzymatic method for the measurement of mannitol in urine

A previously described method for mannitol in urine has been modified and improved. End product inhibition by fructose in the mannitol dehydrogenase method for mannitol has been minimized; the assay is linear over a sample mannitol concentration range of 0-12 mmol/L; no significant interference from other sugars or sugar alcohols could be demonstrated. The method is precise (within-batch CV less than 1%), rapid and shows excellent recovery of mannitol in spiked samples. Comparison with gas liquid chromatography shows excellent correlation (r = 0.994) between the two methods.

Differential sugar absorption for the assessment of canine intestinal permeability: the cellobiose/mannitol test in gluten-sensitive enteropathy of Irish setters

Intestinal permeability was assessed in Irish setters with gluten-sensitive enteropathy by oral administration of an isotonic solution of cellobiose and mannitol, and measurement of their urinary excretion ratio. The cellobiose/mannitol ratio was increased in affected Irish setters fed a wheat-containing diet compared both with littermates reared on a cereal-free diet, with no evidence of jejunal damage, and clinically healthy Irish setters. The ratio fell following six weeks on a gluten-free diet to be comparable with control values, and subsequently increased after six weeks gluten challenge. The results indicate that the cellobiose/mannitol test may be useful for the detection of mucosal damage and for monitoring the response to therapy.

Small intestinal function and dietary status in dermatitis herpetiformis

Small intestinal morphology and function were assessed in 82 patients with dermatitis herpetiformis, 51 of whom were taking a normal diet and 31 a gluten free diet. Methods used were histopathological evaluation of jejunal mucosal biopsy specimens, quantitation of intraepithelial lymphocytes, cellobiose/mannitol permeability test, tissue disaccharidase values, serum antigliadin antibodies, and formal assessment of dietary gluten content by a dietician. There was no correlation between dietary gluten intake and the degree of enteropathy in the 51 patients taking a normal diet, whereas biopsy specimens were normal in 24 of the 31 patients on a gluten free diet, all previously having been abnormal. Eighteen patients on gluten containing diets had normal jejunal histology and in seven of these all tests of small intestinal morphology and function were entirely normal. Intestinal permeability was abnormal and serum antigliadin antibodies were present in most patients with enteropathy. Studies of acid secretion in seven patients showed that hypochlorhydria or achlorhydria did not lead to abnormal permeability in the absence of enteropathy. This study shows that a combination of objective tests of small intestinal architecture and function will detect abnormalities in most dermatitis herpetiformis patients, including some with histologically normal jejunal biopsy specimens. Nevertheless there is a small group in whom all conventional intestinal investigations are entirely normal.