Lactulose-mannitol intestinal permeability test in children with diarrhea caused by rotavirus and cryptosporidium. Diarrhea Working Group, Peru

Herbal-based compounds: A review on treatments of cryptosporidiosis

Cryptosporidium, a monoxenous apicomplexan coccidia, is a prevalent diarrhetic and an opportunistic agent, mainly in immunocompromised individuals. As there are few chemotherapeutic compounds that have limited efficacy, we need to identify new compounds or specific parasite targets for designing more potent drugs to treat cryptosporidiosis. Herbal products with low toxicity, environmental compatibility, wide therapeutic potential, and abundant resources can be considered alternatives for treatment. The current review tried to summarize the studies on plants or herbal bioactive constituents with anti-cryptosporidial activities. Based on constituents, plants act via different mechanisms, and further investigations are needed to clarify the exact mechanisms by which they act on the developmental stages of the parasite or host-parasite relationships.

In silico and in vivo evaluation of the anti-cryptosporidial activity of eugenol

Background

Cryptosporidiosis is an opportunistic parasitic disease widely distributed worldwide. Although Cryptosporidium sp. causes asymptomatic infection in healthy people, it may lead to severe illness in immunocompromised individuals. Limited effective therapeutic alternatives are available against cryptosporidiosis in this category of patients. So, there is an urgent need for therapeutic alternatives for cryptosporidiosis. Recently, the potential uses of Eugenol (EUG) have been considered a promising novel treatment for bacterial and parasitic infections. Consequently, it is suggested to investigate the effect of EUG as an option for the treatment of cryptosporidiosis.

Materials and methods

The in silico bioinformatics analysis was used to predict and determine the binding affinities and intermolecular interactions of EUG and Nitazoxanide (NTZ) toward several Cryptosporidium parvum (C. parvum) lowa II target proteins. For animal study, five groups of immunosuppressed Swiss albino mice (10 mice each) were used. Group I was left uninfected (control), and four groups were infected with 1,000 oocysts of Cryptosporidium sp. The first infected group was left untreated. The remaining three infected groups received NTZ, EUG, and EUG + NTZ, respectively, on the 6th day post-infection (dpi). All mice were sacrificed 30 dpi. The efficacy of the used formulas was assessed by counting the number of C. parvum oocysts excreted in stool of infected mice, histopathological examination of the ileum and liver tissues and determination of the expression of iNOS in the ileum of mice in different animal groups.

Results

treatment with EUG resulted in a significant reduction in the number of oocysts secreted in stool when compared to infected untreated mice. In addition, oocyst excretion was significantly reduced in mice received a combination therapy of EUG and NTZ when compared with those received NTZ alone. EUG succeeded in reverting the histopathological alterations induced by Cryptosporidium infection either alone or in combination with NTZ. Moreover, mice received EUG showed marked reduction of the expression of iNOS in ileal tissues.

Conclusion

Based on the results, the present study signified a basis for utilizing EUG as an affordable, safe, and alternative therapy combined with NTZ in the management of cryptosporidiosis.

Zonulin as a Biomarker for the Development of Celiac Disease

OBJECTIVES

Increased intestinal permeability seems to be a key factor in the pathogenesis of autoimmune diseases, including celiac disease (CeD). However, it is unknown whether increased permeability precedes CeD onset. This study's objective was to determine whether intestinal permeability is altered before celiac disease autoimmunity (CDA) in at-risk children. We also examined whether environmental factors impacted zonulin, a widely used marker of gut permeability.

METHODS

We evaluated 102 children in the CDGEMM study from 2014-2022. We included 51 CDA cases and matched controls, who were enrolled for 12 months or more and consumed gluten. We measured serum zonulin from age 12 months to time of CDA onset, and the corresponding time point in controls, and examined clinical factors of interest. We ran a mixed-effects longitudinal model with dependent variable zonulin.

RESULTS

Children who developed CDA had a significant increase in zonulin in the 18.3 months (range 6-78) preceding CDA compared to those without CDA (slope differential = β = 0.1277, 95% CI: 0.001, 0.255). Among metadata considered, zonulin trajectory was only influenced by increasing number of antibiotic courses, which increased the slope of trajectory of zonulin over time in CDA subjects (P = .04).

CONCLUSIONS

Zonulin levels significantly rise in the months that precede CDA diagnosis. Exposure to a greater number of antibiotic courses was associated with an increase in zonulin levels in CDA subjects. This suggests zonulin may be used as a biomarker for preclinical CeD screening in at-risk children, and multiple antibiotic courses may increase their risk of CDA by increasing zonulin levels.

Zinc Deficiency and Therapeutic Value of Zinc Supplementation in Pediatric Gastrointestinal Diseases

The benefits of zinc in treating certain gastrointestinal (GI) diseases have been recognized for over two decades. This review aims to explore zinc deficiency (ZD) and the potential therapeutic value and safety of zinc supplementation in pediatric GI diseases. A systematic review of published articles on ZD and zinc as adjuvant treatments for GI diseases was conducted using various databases. Children with inflammatory bowel disease (IBD), celiac disease, and those receiving long-term proton pump inhibitor treatments are particularly susceptible to ZD. ZD in children with celiac disease and IBD is attributed to insufficient intake, reduced absorption, and increased intestinal loss as a result of the inflammatory process. Zinc plays a crucial role in maintaining the integrity of the gastric mucosa and exerts a gastroprotective action against gastric lesions. Although considerable evidence supports the use of zinc as adjuvant therapy for certain GI diseases in adults, its use is unspecified in children except for infectious diarrhea. Current evidence suggests that zinc supplementation with well-documented dosages helps reduce the duration of diarrhea in children with acute or persistent diarrhea, while there are no specific guidelines for zinc supplementation in children with IBD and celiac disease. Zinc supplementation appears to be beneficial in peptic ulcer disease or gastroesophageal reflux disease. The available evidence highlights the need for intervention programs to enhance zinc status and reduce the morbidity of certain GI diseases in children.

The potential therapeutic effect of Nigella sativa and Zingiber officinale extracts versus Nitazoxanide drug against experimentally induced cryptosporidiosis in laboratory mice

In this study, the potential anti-cryptosporidial effect of Nigella sativa (black seeds) and Zingiber officinale (ginger) alcoholic extracts versus Nitazoxanide (NTZ) medication was investigated in immunosuppressed (IS) laboratory mice. Parasitological, histopathological studies were used to assess their therapeutic efficacy. Serum level and tissue expression percentage of IFN-γ was also used. Nigella extract succeeded to reduce the mean oocyst counts in the feces of immunosuppressed mice followed by NTZ. Ginger-treated ones showed the lowest reduction percentage. Nigella sativa showed the best results in terms of restoring the normal architecture of ileal epithelium in histopathological sections stained with H&E. NTZ treatment sub-groups showed mild improvement, followed by ginger-treated mice, which showed a slight improvement in small intestine microenvironment. A significant substantial rise in serum and intestinal tissue IFN-γ cytokine levels were recorded in Nigella subgroups compared to those of NTZ and ginger respectively. According to our findings Nigella sativa outperformed Nitazoxanide in terms of anti-cryptosporidial effectiveness and regeneration characteristics revealing a promising medication. When compared to the commonly used Nitazoxanide medication or Nigella extracts, the outcomes of ginger extract were suboptimal.

Differential Response to the Course of Cryptosporidium parvum Infection and Its Impact on Epithelial Integrity in Differentiated versus Undifferentiated Human Intestinal Enteroids

Cryptosporidium is a leading cause of diarrhea and death in young children and untreated AIDS patients and causes waterborne outbreaks. Pathogenic mechanisms underlying diarrhea and intestinal dysfunction are poorly understood. We previously developed stem-cell derived human intestinal enteroid (HIE) models for Cryptosporidium parvum which we used in this study to investigate the course of infection and its effect on intestinal epithelial integrity. By immunofluorescence and confocal microscopy, there was robust infection of undifferentiated and differentiated HIEs in two and three-dimensional (2D, 3D) models. Infection of differentiated HIEs in the 2D model was greater than that of undifferentiated HIEs but lasted only for 3 days, whereas infection persisted for 21 days and resulted in completion of the life cycle in undifferentiated HIEs. Infection of undifferentiated HIE monolayers suggest that C. parvum infects LGR5+ stem cells. Transepithelial electrical resistance measurement of HIEs in the 2D model revealed that infection resulted in decreased epithelial integrity which persisted in differentiated HIEs but recovered in undifferentiated HIEs. Compromised epithelial integrity was reflected in disorganization of the tight and adherens junctions as visualized using the markers ZO-1 and E-cadherin, respectively. Quantitation using the image analysis tools Tight Junction Organizational Rate and Intercellular Junction Organization Quantification, measurement of monolayer height, and RNA transcripts of both proteins by quantitative reverse transcription PCR confirmed that disruption persisted in differentiated HIEs but recovered in undifferentiated HIEs. These models, which more accurately recapitulate human infection, will be useful tools to dissect pathogenic mechanisms underlying diarrhea and intestinal dysfunction in cryptosporidiosis.

Fecal biomarkers of environmental enteric dysfunction and associated factors among children aged 24-59 months in east Dembiya district, northwest Ethiopia

Background

Environmental enteric dysfunction is a subclinical intestinal disorder characterized by gut inflammation accompanied by morphological changes, such as blunted villi and crypt hyperplasia. This is a common illness in low and middle-income countries. However, environmental enteric dysfunction evidence is limited in Ethiopia. Accordingly, this study was conducted to measure fecal biomarkers of environmental enteric dysfunction and associated factors among children aged 24–59 months in rural northwest Ethiopia.

Methods

A community-based cross-sectional study was employed among 235 randomly selected children in a rural setting of the east Dembiya district. Stool samples were collected without fixative and analyzed for fecal biomarkers of environmental enteric dysfunction (Alpha-1-antitrypsin, neopterin, and myeloperoxidase) using commercial enzyme-linked immunosorbent assay kits and analyzed for intestinal parasites using wet mount and Kato-Katz techniques. Child behaviors related with exposure to enteropathogens, condition of the living environment and socio-demographic information were collected using interviewer-administered questionnaire and structure observation. We fitted multivariable linear regression model to assess the association between environmental factors and concentration of fecal biomarkers of environmental enteric dysfunction in the stool. Statistically significant associations were declared based on adjusted betas with the corresponding 95% confidence interval and p-value < 0.05.

Results

The median concentration of fecal markers of environmental enteric dysfunction was 350 μg/ml for Alpha-1-antitrypsin, 3320.2 ng/ml for myeloperoxidase, and 1562 nmol/l for neopterin. The median concentration of Alpha-1-antitrypsin among 161 (68.5%), myeloperoxidase among 168 (71.5%), and neopterin among 188 (80%) of the stool samples were above the normal values in non-tropical settings. Moreover, 100 (42.6%) of the children had high EED disease activity score (above the median score). The elevated concentrations of fecal biomarkers of gut inflammation and the high EED disease activity score were significantly associated with open defecation practice, mouthing of soil contaminated materials, Escherichia coli (E. coli)  contamination of drinking water, E. coli contamination of foods, E. coli contamination of soil, and intestinal parasites.

Conclusion

Overall, Alpha-1-antitrypsin, myeloperoxidase, and neopterin levels among the children in the studied region were highly elevated in comparison to populations in high-income countries. Moreover, the EED disease activity score in significant proportion of children was high, suggesting widespread intestinal inflammation and increased intestinal permeability. Extensive E. coli contamination of the living environment (drinking water, ready-to-eat foods, and courtyard soil), hygiene and sanitation behaviors (such as open defecation and mouthing of soil contaminated materials), and a high burden of intestinal parasites were identified as factors associated with the elevated concentration of fecal biomarkers of environmental enteric dysfunction. Parental care to children to avoid mouthing of soil contaminated materials and other risky behaviors that increase exposure enteric infections, and protecting the living environment (water, food and soil) from fecal contamination are important.

Intestinal permeability before and after albendazole treatment in low and high socioeconomic status schoolchildren in Makassar, Indonesia

Intestinal helminths are highly prevalent in low-SES children and could contribute to poor health outcomes either directly or via alteration of the gut microbiome and gut barrier function. We analysed parasitic infections and gut microbiota composition in 325 children attending high- and low-SES schools in Makassar, Indonesia before and after albendazole treatment. Lactulose/Mannitol Ratio (LMR, a marker of gut permeability); I-FABP (a surrogate marker of intestinal damage) as well as inflammatory markers (LBP) were measured. Helminth infections were highly prevalent (65.6%) in low-SES children. LMR and I-FABP levels were higher in low-SES children (geomean (95%CI): 4.03 (3.67-4.42) vs. 3.22 (2.91-3.57); p. adj < 0.001; and 1.57 (1.42-1.74) vs. 1.25 (1.13-1.38); p. adj = 0.02, respectively) while LBP levels were lower compared to the high-SES (19.39 (17.09-22.01) vs. 22.74 (20.07-26.12); p.adj = 0.01). Albendazole reduced helminth infections in low-SES and also decreased LMR with 11% reduction but only in helminth-uninfected children (estimated treatment effect: 0.89; p.adj = 0.01). Following treatment, I-FABP decreased in high- (0.91, p.adj < 0.001) but increased (1.12, p.adj = 0.004) in low-SES children. Albendazole did not alter the levels of LBP. Microbiota analysis showed no contribution from specific bacterial-taxa to the changes observed. Intestinal permeability and epithelial damage are higher while peripheral blood inflammatory marker is lower in children of low-SES in Indonesia. Furthermore, treatment decreased LMR in helminth-uninfected only.

Advances in therapeutic and vaccine targets for Cryptosporidium: Challenges and possible mitigation strategies

Cryptosporidium is known to be the second most common diarrheal pathogen in children, causing potentially fatal diarrhea and associated with long-term growth stunting and cognitive deficits. The only Food and Drug Administration-approved treatment for cryptosporidiosis is nitazoxanide, but this drug has not shown potentially effective results in susceptible hosts. Therefore, a safe and effective drug for cryptosporidiosis is urgently needed. Cryptosporidium genome sequencing analysis may help develop an effective drug, but both in vitro and in vivo approaches to drug evaluation are not fully standardized. On the other hand, the development of partial immunity after exposure suggests the possibility of a successful and effective vaccine, but protective surrogates are not precise. In this review, we present our current perspectives on novel cryptosporidiosis therapies, vaccine targets and efficacies, as well as potential mitigation plans, recommendations and perceived challenges.

MicroRNA Expression and Intestinal Permeability in Children Living in a Slum Area of Bangladesh

Introduction: MicroRNAs (miRNAs) are small, non-coding RNAs that post-transcriptionally regulate gene expression. Changes in miRNA expression have been reported in a number of intestinal diseases, in both tissue samples and readily accessible specimens like stools. Pathogenic infections, diet, toxins, and other environmental factors are believed to influence miRNA expression. However, modulation of miRNAs in humans is yet to be thoroughly investigated. In this study, we examined the expression levels of two human miRNAs (miRNA-122 and miRNA-21) in stool samples of a group of Bangladeshi children who had an altered/increased intestinal permeability (IIP). Methods: Stool samples were collected from children with IIP (L:M > 0.09) and normal intestinal permeability (NIP) (L:M ≤ 0.09). Quantitative PCR was performed to quantify the levels of miRNA-122 and miR-21 in stools. Commercial ELISA kits were used to measure gut inflammatory markers Calprotectin and REG1B. Serum samples were tested using Human Bio-Plex Pro Assays to quantify IL-1β, IL-2, IL-5, IL-10, IL-13, IFN-γ, and TNF-α. Total nucleic acid extracted from stool specimens were used to determine gut pathogens using TaqMan Array Card (TAC) system real-time polymerase chain reaction. Results: The expression levels of miRNA-122 (fold change 11.6; p < 0.001, 95% CI: 6.14-11.01) and miR-21 (fold change 10; p < 0.001, 95% CI: 5.05-10.78) in stool were upregulated in children with IIP than in children with normal intestinal permeability (NIP). Significant correlations were observed between stool levels of miR-122 and miR-21 and the inflammatory cytokines IL-1β, IL-2, IFN-γ, and TNF-α (p < 0.05). Children with IIP were frequently infected with rotavirus, Campylobacter jejuni, Bacteroides fragilis, adenovirus, norovirus, astrovirus, and various Escherichia coli strains (ETEC_STh, ETEC_STp, EAEC_aaiC, EAEC_aatA) (p < 0.001). miR-122 significantly correlated with the fecal inflammatory biomarkers REG1B (p = 0.015) and Calprotectin (p = 0.030), however miR-21 did not show any correlation with these fecal biomarkers.

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.

Growth velocity in children with Environmental Enteric Dysfunction is associated with specific bacterial and viral taxa of the gastrointestinal tract in Malawian children

Environmental enteric dysfunction (EED) is characterized by diffuse villous atrophy of the small bowel. EED is strongly associated with stunting, a major public health problem linked to increased childhood morbidity and mortality. EED and subsequent stunting of linear growth are surmised to have microbial origins. To interrogate this relationship, we defined the comprehensive virome (eukaryotic virus and bacteriophage) and bacterial microbiome of a longitudinal cohort of rural Malawian children with extensive metadata and intestinal permeability testing at each time point. We found thirty bacterial taxa differentially associated with linear growth. We detected many eukaryotic viruses. Neither the total number of eukaryotic families nor a specific viral family was statistically associated with improved linear growth. We identified 3 differentially abundant bacteriophage among growth velocities. Interestingly, there was a positive correlation between bacteria and bacteriophage richness in children with subsequent adequate/moderate growth which children with subsequent poor growth lacked. This suggests that a disruption in the equilibrium between bacteria and bacteriophage communities might be associated with subsequent poor growth. Future studies of EED and stunting should include the evaluation of viral communities in addition to bacterial microbiota to understand the complete microbial ecology of these poorly understood entities.

Direct Implementation of Intestinal Permeability Test in NMR Metabolomics for Simultaneous Biomarker Discovery-A Feasibility Study in a Preterm Piglet Model

Measurement of intestinal permeability (IP) is often used in the examination of inflammatory gastrointestinal disorders. IP can be assessed by measurement of urinary recovery of ingested non-metabolizable lactulose (L) and mannitol (M). The present study aimed to examine how measurements of IP can be integrated in a NMR-based metabolomics approach for a simultaneous quantification of L/M ratio and biomarker exploration. For this purpose, plasma and urine samples were collected from five-day-old preterm piglets (n = 20) with gastrointestinal disorders (subjected to intra-amniotic lipopolysaccharide (LPS, 1 mg/fetus)) after they had been administrated a 5% lactulose and 5% mannitol solution (15 mL/kg). The collected plasma and urine samples were analyzed by ¹H NMR-based metabolomics. Urine L/M ratio measured by ¹H NMR spectroscopy showed high correlation with the standard measurement of the urinary recoveries by enzymatic assays (r = 0.93, p < 0.05). Partial least squares (PLS) regressions and correlation analyses between L/M ratio and NMR metabolomics data revealed that L/M ratio was positively correlated with plasma lactate, acetate and succinate levels and negatively correlated with urinary hippuric acid and glycine. In conclusion, the present study demonstrated that NMR metabolomics enables simultaneous IP testing and discovery of biomarkers associated with an impaired intestinal permeability.

Children With Noncritical Infections Have Increased Intestinal Permeability, Endotoxemia and Altered Innate Immune Responses

BACKGROUND

Children with critical illness have increased intestinal permeability and a period of immunoparalysis, mediated by elevated circulating endotoxin. Whether children with less severe infections have similar changes is uncertain.

METHODS

We conducted a proof-of-concept pilot study, enrolling children 6-59 months of age hospitalized for noncritical infections (cases, n = 11) and noninfected controls (n = 19). Intestinal permeability was measured by lactulose-mannitol recovery. Plasma endotoxin, blood monocyte and neutrophil immunophenotypes and cytokine elaboration following 24-hour whole-blood culture with antigens targeting distinct innate pathogen recognition receptor signaling pathways were evaluated.

RESULTS

Cases had higher intestinal permeability and plasma endotoxin levels than controls. Among cases versus controls, fewer monocytes expressed human leukocyte antigen DR isotype (HLA-DR) (87.1% vs. 96.4%, P = 0.001), and more expressed CD64 (99.6% vs. 97.6%, P = 0.041). Following zymosan stimulation of whole blood, cases versus controls produced less interleukin 1 beta (IL-1β) (median 1101 vs. 2604 pg/mL, P = 0.048) and tumor necrosis factor alpha (TNF-α) (2342 vs. 5130 pg/mL, P = 0.031). Children with higher (≥0.1 endotoxin unit (EU)/mL) versus lower (<0.1 EU/mL) circulating endotoxin had fewer monocytes expressing CD86 (69.8% vs. 92.4%, P = 0.003) and less expression of CD64 following 24-hour zymosan stimulation (median fluorescence intensity (MFI) 1514 vs. 2196, P = 0.022).

CONCLUSIONS

Children hospitalized with noncritical infections had increased intestinal permeability, endotoxemia and altered monocyte phenotype and function. Collectively, these changes are typical of immunoparalysis seen in children with critical illness and may increase the risk of subsequent infections.

Subclinical Enteric Parasitic Infections and Growth Faltering in Infants in São Tomé, Africa: A Birth Cohort Study

The associations between enteric pathogenic parasites and growth in infants in São Tomé were explored using a refined anthropometric approach to recognize early growth faltering. A birth cohort study was conducted with follow-up to 24 months of age. Microscopic examination for protozoa and soil-transmitted helminths was performed. Anthropometric assessments included: z-scores for weight-for-length (WLZ), length-for-age (LAZ), weight (WAVZ) and length velocities (LAVZ), length-for-age difference (LAD), and wasting and stunting risk (≤-1 SD). Generalized additive mixed effects regression models were used to explore the associations between anthropometric parameters and enteric parasitic infections and cofactors. A total of 475 infants were enrolled, and 282 completed the study. The great majority of infants were asymptomatic. Giardia lamblia was detected in 35.1% of infants in at least one stool sample, helminths in 30.4%, and Cryptosporidium spp. in 14.7%. Giardia lamblia and helminth infections were significantly associated with mean decreases of 0.10 in LAZ and 0.32 in LAD, and of 0.16 in LAZ and 0.48 in LAD, respectively. Cryptosporidium spp. infection was significantly associated with a mean decrease of 0.43 in WAVZ and 0.55 in LAVZ. The underestimated association between subclinical parasitic enteric infections and mild growth faltering in infants should be addressed in public health policies.

Lactoferrin and lysozyme to reduce environmental enteric dysfunction and stunting in Malawian children: study protocol for a randomized controlled trial

Background

Chronic childhood malnutrition, as manifested by stunted linear growth, remains a persistent barrier to optimal child growth and societal development. Environmental enteric dysfunction (EED) is a significant underlying factor in the causal pathway to stunting, delayed cognitive development, and ultimately morbidity and mortality. Effective therapies against EED and stunting are lacking and further clinical trials are warranted to effectively identify and operationalize interventions.

Methods/design

A prospective randomized placebo-controlled parallel-group randomized controlled trial will be conducted to determine if a daily supplement of lactoferrin and lysozyme, two important proteins found in breast milk, can decrease the burden of EED and stunting in rural Malawian children aged 12–23 months old. The intervention and control groups will have a sample size of 86 subjects each. All field and laboratory researchers will be blinded to the assigned intervention group, as will the subjects and their caregivers. The percentage of ingested lactulose excreted in the urine (Δ%L) after 4 h will be used as the biomarker for EED and linear growth as the measure of chronic malnutrition (stunting). The primary outcomes of interest will be change in Δ%L from baseline to 8 weeks and to 16 weeks. Intention-to-treat analyses will be used.

Discussion

A rigorous clinical trial design will be used to assess the biologically plausible use of lactoferrin and lysozyme as dietary supplements for children at high risk for EED. If proven effective, these safe proteins may serve to markedly reduce the burden of childhood malnutrition and improve survival.

Trial Registration

Clinicaltrials.gov, NCT02925026. Registered on 4 October 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2278-8) contains supplementary material, which is available to authorized users.

Association of enteric parasitic infections with intestinal inflammation and permeability in asymptomatic infants of São Tomé Island

The cumulative effect of repeated asymptomatic enteric infections on intestinal barrier is not fully understood in infants. We aimed to evaluate the association between previous enteric parasitic infections and intestinal inflammation and permeability at 24-months of age, in asymptomatic infants of São Tomé Island. A subset of infants from a birth cohort, with intestinal parasite evaluations in at least four points of assessment, was eligible. Intestinal inflammatory response and permeability were assessed using fecal S100A12 and alpha-1-antitrypsin (A1AT), respectively. The cutoff <-1SD for weight-for-length and length-for-age was used to define wasting and stunting. Multivariable linear regression analysis explored if cumulative enteric parasitic infections explained variability of fecal biomarkers, after adjusting for potential confounders. Eighty infants were included. Giardia duodenalis and soil-transmitted helminths (STH) were the most frequent parasites. The median (interquartile range) levels were 2.87 μg/g (2.41-3.92) for S100A12 and 165.1 μg/g (66.0-275.6) for A1AT. Weak evidence of association was found between S100A12 levels and G. duodenalis (p = 0.080) and STH infections (p = 0.089), and between A1AT levels and parasitic infection of any etiology (p = 0.089), at 24-months of age. Significant associations between A1AT levels and wasting (p = 0.006) and stunting (p = 0.044) were found. Previous parasitic infections were not associated with fecal biomarkers at 24 months of age. To summarize, previous asymptomatic parasitic infections showed no association with intestinal barrier dysfunction. Notwithstanding, a tendency toward increased levels of the inflammatory biomarker was observed for current G. duodenalis and STH infections, and increased levels of the permeability biomarker were significantly associated with stunting and wasting.

Validation of an LC-MS/MS Method for Urinary Lactulose and Mannitol Quantification: Results in Patients with Irritable Bowel Syndrome

Aim. Lactulose/mannitol ratio is used to assess intestinal barrier function. Aim of this work was to develop a robust and rapid method for the analysis of lactulose and mannitol in urine by liquid chromatography coupled to tandem mass spectrometry. Lactulose/mannitol ratio has been measured in pediatric patients suffering from irritable bowel syndrome. Methods. Calibration curves and raffinose, used as internal standard, were prepared in water : acetonitrile 20 : 80. Fifty μL of urine sample was added to 450 μL of internal standard solution. The chromatographic separation was performed using a Luna NH2 column operating at a flow rate of 200 μL/min and eluted with a linear gradient from 20% to 80% water in acetonitrile. Total run time is 9 minutes. The mass spectrometry operates in electrospray negative mode. Method was fully validated according to European Medicine Agency guidelines. Results and Conclusions. Linearity ranged from 10 to 1000 mg/L for mannitol and 2.5 to 1000 mg/L for lactulose. Imprecision in intra- and interassay was lower than 15% for both analytes. Accuracy was higher than 85%. Lactulose/mannitol ratio in pediatric patients is significantly higher than that measured in controls. The presented method, rapid and sensitive, is suitable in a clinical laboratory.

The effect of porcine reproductive and respiratory syndrome virus and porcine epidemic diarrhea virus challenge on growing pigs II: Intestinal integrity and function

The objective of this study was to determine if intestinal function and integrity is altered due to porcine reproductive and respiratory syndrome (PRRS) virus and porcine epidemic diarrhea (PED) virus infection in growing pigs. Forty-two gilts (16.8 ± 0.6 kg BW), naïve for PRRS and PED, were selected and randomly assigned to 1 of 4 treatments: 1) a control (CON; = 6), 2) PRRS virus challenge only (PRRS; = 12), 3) PED virus challenge only (; = 12), or 4) coinfection of PRRS + PED viruses (PRP; = 12). Treatments 2 and 4 were inoculated with a live field strain of PRRS virus on d 0 after inoculation. Treatments 3 and 4 were inoculated with PED virus on 14 d after inoculation (dpi) and all pigs were euthanized 7 d later (21 dpi). Infection with PRRS virus was determined by viremia and seroconversion. Fecal quantitative PCR was used to confirm PED virus infection. Control pigs remained PRRS and PED virus negative throughout the study. Compared with the CON, intestinal morphology was unaffected by PRRS. As expected, PED and PRP treatments resulted in duodenum, jejunum, and ileum villus atrophy compared with the CON treatment ( < 0.01). Ex vivo transepithelial electrical resistance (TER) did not differ between CON and PRRS pigs (P < 0.05) but was reduced by 40% in PED alone ( < 0.01). Interestingly, TER was increased ( < 0.01) in the PRP pigs. Active transport of glucose was increased in PRRS pigs over CON pigs ( < 0.01), whereas PED had pigs increased ( < 0.01) active glutamine transport over the CON pigs. Jejunum GLUT2 mRNA abundance and sucrase, maltase, and Na+/K+ adenosine triphosphatase activities tended to be increased in PRRS pigs compared with CON pigs ( < 0.06). The jejunum AA transporter, SLC6A14, and mucin 2 mRNA abundance tended to be increased in PED-only pigs ( < 0.10). These data suggest that PRRS infection supports a higher affinity for glucose uptake, whereas PED favors glutamine uptake. Interestingly, digestive machinery during PED challenge remained intact. Altogether, PED but not PRRS challenges alter intestinal morphology and integrity in growing pigs.

Early Childhood Diarrhea Predicts Cognitive Delays in Later Childhood Independently of Malnutrition

Understanding the complex relationship between early childhood infectious diseases, nutritional status, poverty, and cognitive development is significantly hindered by the lack of studies that adequately address confounding between these variables. This study assesses the independent contributions of early childhood diarrhea (ECD) and malnutrition on cognitive impairment in later childhood. A cohort of 131 children from a shantytown community in northeast Brazil was monitored from birth to 24 months for diarrhea and anthropometric status. Cognitive assessments including Test of Nonverbal Intelligence (TONI), coding tasks (WISC-III), and verbal fluency (NEPSY) were completed when children were an average of 8.4 years of age (range = 5.6-12.7 years). Multivariate analysis of variance models were used to assess the individual as well as combined effects of ECD and stunting on later childhood cognitive performance. ECD, height for age (HAZ) at 24 months, and weight for age (WAZ) at 24 months were significant univariate predictors of the studies three cognitive outcomes: TONI, coding, and verbal performance (P < 0.05). Multivariate models showed that ECD remained a significant predictor, after adjusting for the effect of 24 months HAZ and WAZ, for both TONI (HAZ, P = 0.029 and WAZ, P = 0.006) and coding (HAZ, P = 0.025 and WAZ, P = 0.036) scores. WAZ and HAZ were also significant predictors after adjusting for ECD. ECD remained a significant predictor of coding (WISC III) after number of household income was considered (P = 0.006). This study provides evidence that ECD and stunting may have independent effects on children's intellectual function well into later childhood.

Improving the detection of environmental enteric dysfunction: a lactulose, rhamnose assay of intestinal permeability in children aged under 5 years exposed to poor sanitation and hygiene

Background

Environmental enteric dysfunction (EED) is an asymptomatic intestinal disorder affecting populations living in conditions of poor sanitation and hygiene. The study tested intestinal barrier function in infants with EED.

Methods

We prospectively studied an advanced high-performance liquid chromatography mass spectrometry assay of urine collected after oral intake of the monosaccharide, L-rhamnose and the disaccharide, lactulose, in 112 children from three continents.

Findings

Compared to the US cohort (n=27), the cohorts of children from Peru (n=19) and Zambia (n=85) were older with evidence of growth impairment. The median (range) of age (months) was 8.0 (2.0 to 13.0), 27.0 (15.0 to 29.0) and 21.0 (12.0 to 36.0), respectively. The median (range) of height for age Z score was −0.1 (−1.8 to 2.4), −1.8 (−3.3 to −0.2) and −2.3 (−8.5 to 1.2), respectively. Among children with valid sugar data (n=22 USA, n=19 Peru, n=73 Zambia), there were no significant differences in the median rhamnose urine concentrations between the three groups. The median (range) lactulose concentration (µg/mL) was 6.78 (0.29 to 31.90), 47.60 (4.23 to 379.00) and 75.40 (0.67 to 873.00) in the US, Peruvian and Zambian cohorts, respectively (p<0.001). The lactulose/rhamnose ratio (LRR) was higher in cohorts from Peru (0.75, 0.15, 5.02) and Zambia (2.26, 0.08, 14.48) compared to the US (0.14, 0.06, 1.00) cohort (p<0.001). In a multivariate effect modification model, higher weight-for-age z scores were associated with lower post-dose lactulose when rhamnose excretion was constant (p=0.003).

Conclusions

This non-invasive two saccharide permeability protocol measures changes in intestinal permeability in children with EED and permits the identification of individuals for interventional trials.

Intestinal permeability in children with recurrent respiratory and gastrointestinal symptoms

AIM

Increased intestinal permeability has been reported in asthmatic subjects as well as in patients with gastrointestinal disease, thus suggesting the involvement of all the mucosal immune system. We aimed to assess intestinal permeability according to recurrent respiratory and gastrointestinal symptoms in children with asthma and children with functional gastrointestinal disorders (FGIDs).

METHODS

In 108 outpatients aged 3-14 years (45 asthmatic, 63 with FGIDs), we measured the urinary lactulose/mannitol (L/M) ratio, performed allergy skin prick tests and administered questionnaires for recurrent respiratory and gastrointestinal symptoms starting from at least 2 months which persisted over the previous 4 weeks. L/M ratios were compared with previously reported normal values yielded by our chromatographic method (liquid chromatography-mass spectrometry).

RESULTS

High L/M ratios (>0.030) were less frequent in asthmatic children than in children with FGIDs (9/45: 20% vs. 41/63: 65%, P < 0.001). High L/M ratios were associated with gastrointestinal symptoms in 8/9 asthmatic (P < 0.05) and 39/41 subjects with FGIDs (P < 0.005). L/M ratios were not associated with respiratory symptoms or atopy. In a regression model, a high L/M was predicted by low height, absence of asthma and presence of gastrointestinal symptoms (r = 0.72, P < 0.001).

CONCLUSIONS

Increased intestinal permeability is associated with recurrent gastrointestinal symptoms rather than with recurrent respiratory symptoms in both asthmatic children and those with FGIDs. Our findings do not support the hypothesis of mucosal intestinal damage following an inflammatory stimulus in the respiratory mucosa.

Drug Development Against the Major Diarrhea-Causing Parasites of the Small Intestine, Cryptosporidium and Giardia

Diarrheal diseases are among the leading causes of morbidity and mortality in the world, particularly among young children. A limited number of infectious agents account for most of these illnesses, raising the hope that advances in the treatment and prevention of these infections can have global health impact. The two most important parasitic causes of diarrheal disease are Cryptosporidium and Giardia. Both parasites infect predominantly the small intestine and colonize the lumen and epithelial surface, but do not invade deeper mucosal layers. This review discusses the therapeutic challenges, current treatment options, and drug development efforts against cryptosporidiosis and giardiasis. The goals of drug development against Cryptosporidium and Giardia are different. For Cryptosporidium, only one moderately effective drug (nitazoxanide) is available, so novel classes of more effective drugs are a high priority. Furthermore, new genetic technology to identify potential drug targets and better assays for functional evaluation of these targets throughout the parasite life cycle are needed for advancing anticryptosporidial drug design. By comparison, for Giardia, several classes of drugs with good efficacy exist, but dosing regimens are suboptimal and emerging resistance begins to threaten clinical utility. Consequently, improvements in potency and dosing, and the ability to overcome existing and prevent new forms of drug resistance are priorities in antigiardial drug development. Current work on new drugs against both infections has revealed promising strategies and new drug leads. However, the primary challenge for further drug development is the underlying economics, as both parasitic infections are considered Neglected Diseases with low funding priority and limited commercial interest. If a new urgency in medical progress against these infections can be raised at national funding agencies or philanthropic organizations, meaningful and timely progress is possible in treating and possibly preventing cryptosporidiosis and giardiasis.

Common beans and cowpeas as complementary foods to reduce environmental enteric dysfunction and stunting in Malawian children: study protocol for two randomized controlled trials

Background

Interventions to decrease the burden of childhood malnutrition are urgently needed, as millions of children die annually owing to undernutrition and hundreds of millions more are left cognitively and physically stunted. Environmental enteric dysfunction (EED), a pervasive chronic subclinical inflammatory condition among children that develops when complementary foods are introduced, places them at high risk of stunting, malabsorption, and poor oral vaccine efficacy. Improved interventions to reduce the burden of EED and stunting are expected to markedly improve the nutritional status and survival of children throughout resource-limited settings.

Methods/Design

We will conduct, in parallel, two prospective randomized controlled clinical trials to determine whether common beans or cowpeas improve growth, ameliorate EED, and alter the intestinal microbiome during a high-risk period in the lives of rural Malawian children. Study 1 will enroll children at 6 months of age and randomize them to receive common beans, cowpeas, or a standard complementary food for 6 months. Anthropometry will be compared among the three groups; EED will be assessed using a dual-sugar absorption test and by quantifying human intestinal mRNA for inflammatory messages; and the intestinal microbiota will be characterized by deep sequencing of fecal DNA, to enumerate host microbial populations and their metabolic capacity. Study 2 will enroll children 12–23 months old and follow them for 12 months, with similar interventions and assessments as Study 1.

Discussion

By amalgamating the power of rigorous clinical trials and advanced biological analysis, we aim to elucidate the potential of two grain legumes to reduce stunting and EED in a high-risk population. Legumes have potential as an affordable and effective complementary food intervention, given their cultural acceptability, nutritional content, and agricultural feasibility in sub-Saharan Africa.

Trial registration

Clinicaltrials.gov NCT02472262 and NCT02472301.

Environmental enteric dysfunction: an overview

BACKGROUND

Environmental enteric dysfunction (EED) refers to an incompletely defined syndrome of inflammation, reduced absorptive capacity, and reduced barrier function in the small intestine. It is widespread among children and adults in low- and middle-income countries. Understanding of EED and its possible consequences for health is currently limited.

OBJECTIVE

A narrative review of the current understanding of EED: epidemiology, pathogenesis, therapies, and relevance to child health.

METHODS

Searches for key papers and ongoing trials were conducted using PUBMED 1966-June 2014; ClinicalTrials.gov; the WHO Clinical Trials Registry; the Cochrane Library; hand searches of the references of retrieved literature; discussions with experts; and personal experience from the field.

RESULTS

EED is established during infancy and is associated with poor sanitation, certain gut infections, and micronutrient deficiencies. Helicobacter pylori infection, small intestinal bacterial overgrowth (SIBO), abnormal gut microbiota, undernutrition, and toxins may all play a role. EED is usually asymptomatic, but it is important due to its association with stunting. Diagnosis is frequently by the dual sugar absorption test, although other biomarkers are emerging. EED may partly explain the reduced efficacy of oral vaccines in low- and middle-income countries and the increased risk of serious infection seen in children with undernutrition.

CONCLUSIONS

Despite its potentially significant impacts, it is currently unclear exactly what causes EED and how it can be treated or prevented. Ongoing trials involve nutritional supplements, water and sanitation interventions, and immunomodulators. Further research is needed to better understand this condition, which is of likely crucial importance for child health and development in low- and middle-income settings.

Treatment of Cryptosporidium: What We Know, Gaps, and the Way Forward

Cryptosporidiosis is increasingly recognized as an important global health concern. While initially reported in immunocompromised such as AIDS patients, cryptosporidiosis has now been documented as a major cause of childhood diarrhea and an important factor in childhood malnutrition. Currently, nitazoxanide is the only proven anti-parasitic treatment for Cryptosporidium infections. However, it is not effective in severely immunocompromised patients and there is limited data in infants. Immune reconstitution or decreased immunosuppression is critical to therapy in AIDS and transplant patients. This limitation of treatment options presents a major public health challenge given the important burden of disease. Repurposing of drugs developed for other indications and development of inhibitors for novel targets offer hope for improved therapies, but none have advanced to clinical studies.

Use of the lactulose to mannitol ratio to evaluate childhood environmental enteric dysfunction: a systematic review

Childhood gut dysfunction (enteropathy) is common in resource-poor environments. Stunting is its presumed major consequence. Identification of biomarkers of gut dysfunction could identify the presence of, and, ideally, assess interventions for, enteropathy. Classically, enteropathy has been identified histopathologically. However, less invasive assays may be more sensitive for detecting earlier perturbations reflecting specific functional derangements. The most commonly used test has been the urinary lactulose to mannitol ratio (L:M), which primarily assesses gut leakiness, and which also measures absorption. We systematically reviewed the L:M literature published from 2000 to 2010 pertinent to children in developing country settings, and identified 25 relevant publications representing heterogeneous studies. We conclude that the L:M test has many attributes, including reflecting 2 physiologic processes (absorption and permeability) and likely correlation with growth failure consequent to child gut dysfunction. However, improved test technical performance, data reporting, and correlation with host phenotypes are needed to maximize the utility of this test.

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.

The effects of micronutrient-fortified complementary/replacement food on intestinal permeability and systemic markers of inflammation among maternally HIV-exposed and unexposed Zambian infants

The present randomised trial investigated the effects of feeding Zambian infants from 6 to 18 months old either a richly or basal micronutrient-fortified complementary/replacement food on gut integrity and systemic inflammation. Blood samples were obtained from all infants (n 743) at 6 and 18 months for the assessment of serum C-reactive protein (CRP) and α1-acid glycoprotein (AGP). A subsample of 502 infants, selected from the main cohort to include a larger proportion of infants with HIV-positive mothers, was assigned to lactulose/mannitol gut permeability tests. Lactulose:mannitol (L:M) ratio analyses were adjusted for baseline urinary L:M ratio, socio-economic status, mother's education, season of birth and baseline stunting, and stratified by maternal antenatal HIV status, child's sex, concurrent breast-feeding status and anaemia at baseline. There was no significant difference in geometric mean L:M ratio between the richly fortified and basal-fortified porridge arms at 12 months (0·47 (95 % CI 0·41, 0·55) v. 0·41 (95 % CI 0·34, 0·49); P = 0·16 adjusted). At 18 months, the richly fortified porridge group had a significantly higher geometric mean L:M ratio than the basal-fortified group (0·23 (95 % CI 0·19, 0·28) v. 0·15 (95 % CI 0·12, 0·19); P = 0·02 adjusted). This effect was evident for all stratifications, significantly among boys (P = 0·04), among the infants of HIV-negative mothers (P = 0·01), among the infants of HIV-negative mothers not concurrently breast-fed (P = 0·01) and among those who were not anaemic at baseline (P = 0·03). CRP, but not AGP, was positively associated with L:M ratio, but there were no significant effects of the diet on either CRP or AGP. In conclusion, a richly fortified complementary/replacement food did not benefit and may have worsened intestinal permeability.

The cell biology of cryptosporidium infection

Cryptosporidiosis remains a significant cause of enteric disease worldwide. Basic investigations of host: pathogen interactions have revealed the intricate processes mediating infection. The following summarizes the interactions that mediate infection and the host responses that both permit and ultimately clear the infection.

Abnormal small intestinal permeability in patients with idiopathic malabsorption in tropics (tropical sprue) does not change even after successful treatment

BACKGROUND

Though tropical sprue (TS) is common in tropics, studies on small intestinal permeability (SIP) in TS are scant.

METHOD

SIP was evaluated using (1)H nuclear magnetic resonance (NMR) spectroscopy of urinary lactulose and mannitol in 24 patients with TS (22 before and 15 after treatment with tetracycline and folate) and in 31 healthy subjects (HS). Effect of treatment of TS on SIP and its relationship with outcome were studied.

RESULT

Subjects were comparable in terms of age and gender. Before treatment, urinary lactulose (0.24 mmol, 0-1.09 mmol versus 0.09 mmol, 0-0.68 mmol, P=0.02) and lactulose-to-mannitol (L/M) ratio (0.11, 0-0.41 versus 0.042, 0-0.26, P=0.001) were higher in TS than in HS, though mannitol was comparable (2.7 mmol, 0.61-10.5 mmol versus 3.8 mmol, 1.3-16.4 mmol, P=0.08). Patients improved after treatment [stool frequency (9, 4-20/day versus 1, 1-2/day, P<0.0001), weight (44.4, 32-69 kg, versus 56, 39-84 kg, P<0.0001), fecal fat (10.1, 6-26 g/24 h versus 4.4, 3.0-6.7 g/24 h, P<0.0001), D-xylose (0.57, 0.28-1.2 g/5 g/5 h versus 1.1, 0.2-2.1 g/5 g/5 h, P<0.0001), and small intestinal bacterial overgrowth (SIBO) resolved in 10/24 (41.7%) versus 1/15 (6.6%), P=0.02]. Though urinary lactulose (0.17, 0-4.3 mmol versus 0.09, 0-0.68 mmol, P=0.11) and mannitol (2.17, 0.8-36.7 mmol versus 3.84, 1.3-16.4 mmol, P=0.06) were comparable, L/M ratio was higher in TS than in HS (0.09, 0-0.22 versus 0.042, 0-0.26, P=0.002). L/M ratio was more often abnormal (cutoff 0.078) in TS than in HS [14/22 (63.6%) versus 3/31 (9.7%); P=0.0001], which persisted even after treatment [9/15 (60%) as compared with HS; P=0.0006]. Persistently abnormal SIP was associated with less weight gain and frequent stools following treatment.

CONCLUSION

SIP is often abnormal in TS and remains unchanged even after successful treatment that was associated with less weight gain and more frequent stool.

Intestinal mucosal permeability of severely underweight and nonmalnourished Bangladeshi children and effects of nutritional rehabilitation

OBJECTIVE

Lactulose/mannitol (L/M) intestinal permeability tests were completed to compare the intestinal function of severely underweight children recovering from diarrhea and other illnesses and of nonmalnourished children from the same communities, and to evaluate the effects of food supplementation, with or without psychosocial stimulation, on the changes in intestinal function among the underweight children.

PATIENTS AND METHODS

Seventy-seven malnourished children completed intestinal permeability studies at baseline and 3 months after receiving 1 of the following randomly assigned treatment regimens: group-C--fortnightly follow-up at community-based follow-up units, including growth monitoring and promotion, health education, and micronutrient supplementation, n = 17; group-SF--same as group-C plus supplementary food (SF) to provide 150 to 300 kcal/day, n = 23; group-PS--same as group-C plus psychosocial stimulation (PS), n = 17; or group-SF + PS--same as group-C plus SF and PS, n = 20. Seventeen nonmalnourished children were included as comparison subjects.

RESULTS

The malnourished children's mean ± SD initial age was 13.1 ± 4.0 months, their mean weight-for-age z score was -3.82 ± 0.61, and their median (interquartile range) urinary L/M recovery ratio was 0.16 (0.10-0.28). Eighty-four percent of the children had L/M ≥ 0.07, suggestive of impaired intestinal function. The median L/M of the malnourished children was significantly greater than that of 17 relatively well-nourished children (median 0.09; interquartile range 0.05-0.12; P = 0.001). There were no significant differences in baseline characteristics of the severely malnourished children by treatment group. Following treatment, the L/M ratio improved in all of the groups (P < 0.001), but there were no significant differences in these changes by treatment group. There was a significant positive association between weight gain and the magnitude of improvement in L/M ratio (r = 0.30, P = 0.012).

CONCLUSIONS

Intestinal mucosal function, as measured by sugar permeability, is impaired among severely underweight children. Intestinal permeability improves in relation to weight gain, but intestinal mucosal recovery is not specifically related to the types or amount of food supplementation or PS provided in this trial.

PPAR-alpha Contributes to the Anti-Inflammatory Activity of Verbascoside in a Model of Inflammatory Bowel Disease in Mice

The previous results suggest that peroxisome proliferator-activated receptor-alpha (PPAR)-α, an intracellular transcription factor activated by fatty acids, plays a role in control of inflammation. There is persuasive epidemiological and experimental evidence that dietary polyphenols have anti-inflammatory activity. In this regard, it has been demonstrated that verbascoside (VB) functions as intracellular radical scavenger and reduces the microscopic and macroscopic signs of experimental colitis. With the aim to characterize the role of PPAR-α in VB-mediated anti-inflammatory activity, we tested the efficacy of VB in an experimental model of inflammatory bowel disease induced by dinitrobenzene sulfonic acid, comparing mice lacking PPAR-α (PPAR-αKO) with wild type (WT) mice. Results indicate that VB-mediated anti-inflammatory activity is weakened in PPAR-αKO mice, compared to WT controls, especially in the inhibition of neutrophil infiltration, intestinal permeability and colon injury. These results indicate that PPAR-α can contribute to the anti-inflammatory activity of VB in inflammatory bowel disease.

A randomized, double-blind, placebo-controlled trial of rifaximin, a nonabsorbable antibiotic, in the treatment of tropical enteropathy

OBJECTIVES

Tropical enteropathy is characterized by an increased urinary lactulose-to-mannitol (L:M) ratio on a site-specific sugar absorption test and is associated with increased intestinal permeability and decreased nutrient absorptive capacity. The etiology of tropical enteropathy is postulated to be intestinal bacterial overgrowth. This study tested the hypothesis that treatment with a nonabsorbable, broad-spectrum antibiotic, rifaximin, reduces the L:M ratio in rural Malawian children, among whom tropical enteropathy is common.

METHODS

All children aged 3-5 years from one village were enrolled in a randomized, double-blind, placebo-controlled trial of treatment with rifaximin for 7 days. The L:M ratio was measured before and after treatment, and the change in the L:M ratio was the primary outcome. Secondary outcomes were changes in the urinary sucrose-to-lactulose (SUC:L) and sucralose-to-lactulose (SCL:L) ratios, as well as changes in the fractions of each test sugar recovered in the urine.

RESULTS

A total of 144 children participated in this study, of whom 76% had an elevated L:M ratio on enrollment (L:M > or = 0.10). Children who received rifaximin did not show an improvement in their L:M ratio compared with those who received placebo (-0.01+/-0.12 vs. 0.02+/-0.16, respectively, P=0.51, mean+/-s.d.), nor were there significant differences between the two groups in excretion of lactulose, mannitol, sucralose, or sucrose, or in the SUC:L and SCL:L ratios.

CONCLUSIONS

Rifaximin had no effect on the tropical enteropathy of 3-5-year-old Malawian children, suggesting that small-bowel bacterial overgrowth is not an important etiological factor in this condition.

Non-invasive investigation in patients with inflammatory joint disease

Gut inflammation can occur in 30%-60% of patients with spondyloarthropathies. However, the presence of such gut inflammation is underestimated, only 27% of patients with histological evidence of gut inflammation have intestinal symptoms, but subclinical gut inflammation is documented in two-thirds of patients with inflammatory joint disease. There are common genetic and immunological mechanisms behind concomitant inflammation in the joints and intestinal tract. A number of blood tests, e.g. erythrocyte sedimentation rate, orosomucoid, C-reactive protein, and white cell and platelet counts, are probably the most commonly used laboratory markers of inflammatory disease, however, these tests are difficult to interpret in arthropathies associated with gut inflammation, since any increases in their blood levels might be attributable to either the joint disease or to gut inflammation. Consequently, it would be useful to have a marker capable of separately identifying gut inflammation. Fecal proteins, which are indirect markers of neutrophil migration in the gut wall, and intestinal permeability, seem to be ideal for monitoring intestinal inflammation: they are easy to measure non-invasively and are specific for intestinal disease in the absence of gastrointestinal infections. Alongside the traditional markers for characterizing intestinal inflammation, there are also antibodies, in all probability generated by the immune response to microbial antigens and auto-antigens, which have proved useful in establishing the diagnosis and assessing the severity of the condition, as well as the prognosis and the risk of complications. In short, non-invasive investigations on the gut in patients with rheumatic disease may be useful in clinical practice for a preliminary assessment of patients with suspected intestinal disease.

A liquid chromatography/mass spectrometry method for the evaluation of intestinal permeability

OBJECTIVES

Lactulose to mannitol ratio (L/M) in urine is used as a non invasive assay to measure intestinal permeability. We describe here a rapid, specific and sensitive LC-MS/MS method for the measurement of these compounds in urine of children affected by abdominal recurrent pain (ARP).

DESIGN AND METHODS

The study has been performed on 50 children from the Pediatric Unit. The chromatographic separation was accomplished by using an NH(2)-column, the detection with a Q-Trap 2000 system.

RESULTS

Multiple calibration curve exhibited consistent linearity and reproducibility. Linear responses were observed in the concentration range 0-400 microg/mL for both mannitol and lactulose. Limits of detection were 12.5 mg/L for lactulose and 1.25 mg/L for mannitol with a signal-to-noise ratio of 10.

CONCLUSIONS

The comparison of L/M values of healthy children with those found in children affected by idiopathic ARP demonstrates that in the latter subjects an alteration of intestinal permeability occurs. The method can represent a useful tool to monitor the intestinal functionality in children with ARP conditions and help for an accurate patient discrimination for diet restrictions.

5-lipoxygenase modulates the alteration of paracellular barrier function in mice ileum during experimental colitis

Small intestine permeability is frequently altered in inflammatory bowel disease and may be caused by the translocation of intestinal toxins through leaky small intestine tight junctions (TJs) and adherence. Recently, it has been shown that 5-lipoxygenase (5-LO) plays an important role in the development of various inflammatory conditions like inflammatory bowel disease. In the present study, by comparing the responses in wild-type mice (5-LOWT) with those of mice lacking the 5-lipoxygenase (5-LOKO), we investigated the role played by this enzyme in the permeability and structure of small intestine TJs in an animal model of experimental colitis. To address this question, we used an experimental model of colitis, induced by dinitrobenzene sulfonic acid (DNBS). Four days after colitis induction by DNBS, the ileal TJs were studied by means of transmission electron microscopy using lanthanum nitrate and immunohistochemistry of occludin and ZO-1. When compared with DNBS-treated 5-LOWT mice, DNBS-treated 5-LOKO mice experienced a reduced rate of the extent and severity of the histological signs of colon injury. After administration of DNBS, 5-LOWT mice showed a significant increase of ileal permeability (88.3% +/- 1.2%) compared with sham (5.6% +/- 0.5%). In colitis, the percentage of "leaky" junctions in terminal ilea correlated positively with the macroscopic colon damage score. Distal colitis in 5-LOWT mice induces an increase of TJ permeability throughout the entire small intestine, and the extent of alterations correlates with colonic damage. On the contrary, a significant reduction of (1) the degree of colon injury, (2) the alteration of ZO-1 and occludin localization (immunohistochemistry), and (3) ileal permeability (8.1% +/- 0.7%) caused by DNBS in the colon was observed in 5-LOKO mice. Similarly, the treatment of 5-LOWT with zileuton (50 mg/kg per oral gavage twice a day), a 5-LO inhibitor, resulted in a significant reduction of all the previously described parameters. Taken together, our results clearly demonstrate that 5-LO modulates small intestinal permeability in experimental colitis through the regulation of TJ protein.

Arginine activates intestinal p70(S6k) and protein synthesis in piglet rotavirus enteritis

We previously showed that phosphorylation of p70 S6 kinase (p70(S6k)) in the intestine is increased during viral enteritis. In this study, we hypothesized that during rotavirus infection, oral Arg, which stimulates p70(S6k) activation, will further stimulate intestinal protein synthesis and mucosal recovery, whereas the p70(S6k) inhibitor rapamycin (Rapa) will inhibit mucosal recovery. Newborn piglets were fed a standard milk replacer diet supplemented with Arg (0.4 g x kg(-1) x d(-1), twice daily by gavage), Rapa (2 mg x m(-2) x d(-1)), Arg + Rapa, or saline (controls). They were infected on d 6 of life with porcine rotavirus. Three days postinoculation, we measured the piglets' body weight, fecal rotavirus excretion, villus-crypt morphology, epithelial electrical resistance in Ussing chambers, and p70(S6k) activation by Western blotting and immunohistochemistry. We previously showed a 2-fold increase in jejunal protein synthesis during rotavirus diarrhea. In this experiment, Arg stimulated jejunal protein synthesis 1.3-fold above standard medium, and the Arg stimulation was partially inhibited by Rapa. Small bowel stimulation of p70(S6k) phosphorylation and p70(S6k) levels were inhibited >80% by Rapa. Immunohistochemistry revealed a major increase of p70(S6k) and ribosomal protein S6 phosphorylation in the crypt and lower villus of the infected piglets. However, in Arg-treated piglets, p70(S6k) activation occurred over the entire villus. Jejunal villi of the Rapa-treated group showed inactivation of p70(S6k) and a decrease in mucosal resistance (reflecting increased permeability), the latter of which was reversed by Arg. We conclude that, early in rotavirus enteritis, Arg has no impact on diarrhea but augments intestinal protein synthesis in part by p70(S6k) stimulation, while improving intestinal permeability via a mammalian target of rapamycin/p70(S6k)-independent mechanism.

An updated review on Cryptosporidium and Giardia

Cryptosporidium and Giardia are two of the most commonly occurring enteric protozoans. They are responsible for diarrheal diseases that may lead to nutritional deficiencies and significant morbidity and mortality, especially among children in developing countries and patients who have immune defects. Both are difficult to diagnose with microscopic techniques. This article provides an updated review of the epidemiology, pathogenesis, clinical manifestations, and treatment of Cryptosporidium and Giardia.

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.

Haplotypes in the CTLA4 region are associated with coeliac disease in the Irish population

Chromosomal region 2q33 encodes the immune regulatory genes, CTLA4, ICOS and CD28, which are involved in regulation of T-cell activity and has been studied as a candidate gene locus in autoimmune diseases, including coeliac disease (CD). We have investigated whether an association exists between this region and CD in the Irish population using a comprehensive analysis for genetic variation. Using a haplotype-tagging approach, this gene cluster was investigated for disease association in a case-control study comprising 394 CD patients and 421 ethnically matched healthy controls. Several SNPs, including CTLA4_CT60, showed association with disease; however, after correction for multiple-testing, CTLA4-658C/T was the only polymorphism found to show significant association with disease when allele, genotype, or carrier status frequency were analysed (carrier status (Allele C), P = 0.0016). Haplotype analysis revealed a haplotype incorporating the CD28/CTLA4 and two 5' ICOS polymorphisms to be significantly associated with disease (patients 24.1%; controls 31.5%; P = 0.035), as was a shorter haplotype composed of the CTLA4 markers only (30.9 vs 34.9%; P = 0.042). The extended haplotype incorporating CD28/CTLA4 and 5' ICOS is more strongly associated with disease than haplotypes of individual genes. This suggests a causal variant associated with this haplotype may be associated with disease in this population.

5-Lipoxygenase modulates colitis through the regulation of adhesion molecule expression and neutrophil migration

Leukotrienes play a part in inflammatory response. The unique role of the enzyme 5-lipoxygenase (5-LO) in the production of leukotrienes makes it as therapeutic target for inflammatory conditions like inflammatory bowel disease (IBD). In the present study, by comparing the responses in wild-type mice (5-LOWT) and mice lacking the 5-lipoxygenase (5-LOKO), we investigated the role played by this enzyme in the development of experimental colitis. To address this question, we used an experimental model of colitis, induced by dinitrobenzene sulfonic acid (DNBS). When compared to DNBS-treated 5-LOWT mice, DNBS-treated 5-LOKO mice experienced a reduced rate of the extent and severity of the histological signs of colon injury. After administration of DNBS 5-LOWT mice showed hemorrhagic diarrhea, weight loss and large areas of necrosis in the mucosa of the colon. Neutrophil infiltration was associated with the expression of ICAM-1, VCAM-1, P-selectin, E-selectin that were mainly localized around vessels. Absence of a functional 5-LO resulted in a significant reduction of all the above-described parameters. In particular, we have observed a significant reduction of: (i) the degree of colon injury, (ii) the rise in myeloperoxidase (MPO) activity (mucosa), (iii) the increase in staining (immunohistochemistry) for ICAM-1, VCAM-1, P-selectin, E-selectin caused by DNBS in the colon. Similarly, the treatment of 5-LOWT with zileuton (50 mg/kg per os twice a day) resulted in a significant reduction of all the above-described parameters. In addition, in in vitro study a significantly reduced chemotactic response to IL-8 was observed in peripheral blood leukocytes from 5-LOKO in comparison to 5-LOWT polymorphonuclear leukocyte. Similar results were obtained when we analyzed the chemotactic response of 5-LOWT cell incubated for 15 min with zileuton (50 microg/ml). Taken together, our results clearly demonstrate that 5-LO modulates neutrophil infiltration in experimental colitis through the expression of adhesion molecules.

Nitric oxide synthase stimulates prostaglandin synthesis and barrier function in C. parvum-infected porcine ileum

Cell culture models implicate increased nitric oxide (NO) synthesis as a cause of mucosal hyperpermeability in intestinal epithelial infection. NO may also mediate a multitude of subepithelial events, including activation of cyclooxygenases. We examined whether NO promotes barrier function via prostaglandin synthesis using Cryptosporidium parvum-infected ileal epithelium in residence with an intact submucosa. Expression of NO synthase (NOS) isoforms was examined by real-time RT-PCR of ileal mucosa from control and C. parvum-infected piglets. The isoforms mediating and mechanism of NO action on barrier function were assessed by measuring transepithelial resistance (TER) and eicosanoid synthesis by ileal mucosa mounted in Ussing chambers in the presence of selective and nonselective NOS inhibitors and after rescue with exogenous prostaglandins. C. parvum infection results in induction of mucosal inducible NOS (iNOS), increased synthesis of NO and PGE2, and increased mucosal permeability. Nonselective inhibition of NOS (NG-nitro-L-arginine methyl ester) inhibited prostaglandin synthesis, resulting in further increases in paracellular permeability. Baseline permeability was restored in the absence of NO by exogenous PGE2. Selective inhibition of iNOS [L-N6-(1-iminoethyl)-L-lysine] accounted for approximately 50% of NOS-dependent PGE2 synthesis and TER. Using an entire intestinal mucosa, we have demonstrated for the first time that NO serves as a proximal mediator of PGE2 synthesis and barrier function in C. parvum infection. Expression of iNOS by infected mucosa was without detriment to overall barrier function and may serve to promote clearance of infected enterocytes.

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.

Enteric pathogens, intestinal permeability and nitric oxide production in acute gastroenteritis

BACKGROUND

Aboriginal children hospitalized with diarrheal disease in northern Australia have high rates of acidosis, hypokalemia and osmotic diarrhea, as well as abnormal small bowel permeability and elevated nitric oxide (NO) production.

METHODS

In a study of 291 diarrheal admissions and 84 controls, we examined the relationship of diarrheal severity outcomes with specific enteric pathogens. NO production was measured by urine nitrate plus nitrite excretion on a low nitrate diet, small bowel permeability by the lactulose:rhamnose ratio on a timed blood specimen and stool pathogens by standard microbiologic investigations and PCR.

RESULTS

The addition of diagnostic tests for diarrheagenic Escherichia coli to standard stool microbiologic testing increased the rate of specific diagnoses from 53% to 75%, but with multiple pathogens isolated from 34%. The most frequently isolated pathogens from diarrheal patients were enteroaggregative E. coli (28.9%), rotavirus (26.5%), enteropathogenic E. coli (17.2%), Salmonella spp. (10.7%), Cryptosporidium parvum (7.2%) and Strongyloides stercoralis (7.2%). High geometric mean permeability ratios (95% confidence intervals) occurred with rotavirus (19.6; 15.3 to 25.1), enteroaggregative E. coli (21.2; 15.3 to 29.3) and Cryptosporidium (23.0; 15.1 to 35.1) compared with 9.4 (6.8 to 13.1) for no pathogens. NO production was highest for Cryptosporidium (3.7; 2.3 to 6.1) compared with 0.6 (0.4 to 1.1) for no pathogens. Multiple regression analysis revealed significant associations (P < 0.001) for rotavirus with acidosis and osmotic diarrhea, for Strongyloides with wasting and hypokalemia and for Cryptospoidium with severe and prolonged diarrhea.

CONCLUSIONS

Cryptosporidium, Strongyloides, rotavirus and enteroaggregative E. coli are important contributors to the severe manifestations of acute gastroenteritis in Australian Aboriginal children.

Recombinant human tissue transglutaminase for diagnosis and follow-up of childhood coeliac disease

Highly discriminatory markers for celiac disease are needed to identify children with early mucosal lesions and for rapid follow-up. The aim of this study was to evaluate the potential of circulating anti-tissue transglutaminase (tTG) IgA and IgG antibodies in the diagnosis and follow-up of childhood celiac disease. An ELISA using recombinant human tTG was used to measure the levels of IgA and IgG anti-tTG antibodies in 226 serum samples from 57 children with biopsy-verified celiac disease, 29 disease control subjects, and 24 healthy control subjects. All samples were also analyzed for anti-endomysium antibodies (EMA). The levels of IgA and IgG anti-tTG antibodies correlated with the condition of the small intestinal villous structure and the serum levels of IgA EMA. All of the 25 serum samples obtained from untreated patients contained IgA anti-tTG antibodies, and 24 of 25 also had IgA EMA. Of the serum samples from 53 control children, two had IgA anti-tTG antibodies and two had IgA EMA. Children younger than 5 y of age with untreated celiac disease had the highest serum levels of both IgA and IgG anti-tTG. There was already an increase in IgA anti-tTG antibodies after 2 wk of gluten challenge (p < 0.01). Although the criteria-based diagnosis of childhood celiac disease still depends on histologic evaluation of intestinal biopsies, detection of anti-tTG antibodies provides useful complementary diagnostic information. The human recombinant tTG-based ELISA can be used as a sensitive and specific test to support the diagnosis and may also be used in the follow-up of treatment in childhood celiac disease.