Jejunal mucosal morphometry in children with and without gut symptoms and in normal adults

Duodenal quantitative mucosal morphometry in children with environmental enteric dysfunction: a cross-sectional multi-country analysis

BACKGROUND

Environmental enteric dysfunction (EED), a chronic inflammatory condition of the small intestine, is an important driver of childhood malnutrition globally. Quantifying intestinal morphology in EED allows for exploration of its association with functional and disease outcomes.

OBJECTIVE

We sought to define morphometric characteristics of childhood EED and determine whether morphology features were associated with disease pathophysiology.

METHODS

Morphometric measurements and histology were assessed on duodenal biopsy slides for this cross-sectional study from children with EED in Bangladesh, Pakistan, and Zambia (n=69), and those with no pathologic abnormality (NPA; n=8) or celiac disease (n=18) in North America. Immunohistochemistry was also conducted on 46, 8, and 18 biopsy slides, respectively. Linear mixed-effects regression models were used to reveal morphometric differences between EED compared to NPA or celiac disease, and identify associations between morphometry and histology or immunohistochemistry amongst children with EED.

RESULTS

In duodenal biopsies, median EED villus height (248 μm), crypt depth (299 μm), and villus:crypt (V:C) ratio (0.9) values ranged between those of NPA (396 μm villus height; 246 μm crypt depth; 1.6 V:C ratio) and celiac disease (208 μm villus height; 365 μm crypt depth; 0.5 V:C ratio). Among EED biopsy slides, morphometric assessments were not associated with histologic parameters or immunohistochemical markers, other than pathologist determined subjective semi-quantitative villus architecture.

CONCLUSIONS

Morphometric analysis of duodenal biopsy slides across geographies identified morphologic features of EED, specifically short villi, elongated crypts, and a smaller V:C ratio relative to NPA slides; although not as severe as in celiac slides. Morphometry did not explain other EED features, suggesting that EED histopathologic processes may be operating independently of morphology. While acknowledging the challenges with obtaining relevant tissue, these data form the basis for further assessments of the role of morphometry in EED.

Epithelial Abnormalities in the Small Intestine of Zambian Children With Stunting

Background

Environmental enteropathy (EE) contributes to impaired linear growth (stunting), in millions of children worldwide. We have previously reported that confocal laser endomicroscopy (CLE) shows fluorescein leaking from blood to gut lumen in vivo in adults and children with EE. We set out to identify epithelial lesions which might explain this phenomenon in Zambian children with stunting non-responsive to nutritional support.

Methods

We performed confocal laser endomicroscopy (CLE) in 75 children and collected intestinal biopsies for histology in 91 children. CLE videos were evaluated, employing the Watson score to determine severity of leakiness. Morphometry was carried out on well-orientated mucosa and 3 biopsies were examined by electron microscopy.

Results

Confocal laser endomicroscopy demonstrated substantial leakage from circulation to gut lumen in 73 (97%) children. Histology consistently showed characteristic changes of EE: villus blunting, lamina propria and epithelial inflammation, and depletion of secretory cells (Paneth cells and goblet cells). Epithelial abnormalities included marked variability in epithelial height, disorganised and shortened microvilli, dilated intercellular spaces, pseudostratification, formation of synechiae between epithelium on adjacent villi, crypt destruction, and abundant destructive lesions which may correspond to the microerosions identified on CLE.

Conclusion

Epithelial abnormalities were almost universal in Zambian children with non-responsive stunting, including epithelial microerosions, cell-cell adhesion anomalies, and defects in secretory cells which may all contribute to impairment of mucosal barrier function and microbial translocation.

Oral delivery of peptide therapeutics in infants: Challenges and opportunities

The vast majority of drugs are not designed or developed for pediatric and infant populations. Peptide drugs, which have become increasingly relevant in the past several decades, are no exception. Unfortunately, nearly all of the 60+ approved peptide drugs are formulated for injection, a particularly unfriendly mode of administration for infants. Although three peptide drugs were recently approved for oral formulations, this major advance in peptide drug delivery is available only for adults. In this review, we consider the current challenges and opportunities for the oral formulation of peptide therapeutics, specifically for infant populations. We describe the strategies that enable oral protein delivery and the potential impact of infant physiology on those strategies. We also detail the limited but encouraging progress towards 1) adapting conventional drug development and delivery approaches to infants and 2) designing novel infant-centric formulations. Together, these efforts underscore the feasibility of oral peptide delivery in infants and provide motivation to increase attention paid to this underserved area of drug delivery and formulation.

Starvation and Its Effects on the Gut

There is growing awareness that intestinal dysfunction determines the clinical outcomes of situations as diverse as undernourished children in urban tropical slums and undernourished surgical patients in intensive care units. As experimental starvation in humans has only rarely been studied, and largely not using current biomedical research tools, we must draw inference from disparate clinical and experimental observations as to the derangements present in the starved gut. There is good evidence of intestinal atrophy and achlorhydria in starvation and severe undernutrition. Historical reports from concentration camps and conflict settings consistently reported a noncontagious phenomenon called "hunger diarrhea," but in settings where starved individuals are isolated from others (prisoners on hunger strike, anorexia nervosa) diarrhea is not a feature. Changes in intestinal permeability and absorption have been infrequently studied in experimental starvation; available data suggest that short-term starvation reduces sugar absorption but not permeability. Severe acute malnutrition in children is associated with severe changes in the intestinal mucosa. Experimental animal models may help explain some observations in humans. Starved rats develop a hypersecretory state and intestinal barrier defects. Starved pigs demonstrate prolongation of rotavirus diarrhea and reproduce some of the absorptive and barrier defects observed in malnourished children. However, there remains much to be learned about the effects of starvation on the gut. Given the high prevalence of undernutrition in hospitals and disadvantaged communities, the lack of attention to the interaction between undernutrition and gastrointestinal damage is surprising and needs to be corrected. Current sophisticated cellular and molecular techniques now provide the opportunity to create fresh understanding of gastrointestinal changes in pure undernutrition, using volunteer studies and samples from anorexia nervosa.

Safety and Ethics in Endoscopic Studies in Children: Evidence From the BEECH Study in Zambia

BACKGROUND

Environmental enteropathy is an example of a poorly-understood intestinal disorder affecting millions of children worldwide, characterized by malabsorption and stunting. Although there is increasing interest in non-invasive means of assessing intestinal structure and function, the potential value of intestinal biopsy for histology, immunostaining, RNA sequencing and epigenetic work means that endoscopic biopsy remains extremely valuable. We here report our experience in the BEECH (Biomarkers of Environmental Enteropathy in CHildren) study of stunting in Zambia, in the belief that it may help address the knowledge gap regarding the safety of endoscopic biopsy in vulnerable young children.

METHODS

We report our experience of safety in 119 children undergoing endoscopic biopsy in the BEECH study in Lusaka Children's Hospital, Lusaka, and discuss ethical considerations in this light.

RESULTS

Upper gastrointestinal endoscopy was performed on children with stunting (length-for-age z score -2 or less) not responsive to nutritional interventions. Conscious sedation was provided by anaesthetists. Of 119 children, 5 (4%) developed transient desaturation, but no serious adverse events were experienced; no clinical, demographic or anaesthetic characteristics were identified as predictive of desaturation. Two children derived clinically useful information from the endoscopy, one life-saving. Of 105 lactase tests, 59 (54%) showed hypolactasia.

DISCUSSION

Children with stunting underwent endoscopy safely, and some derived clinical benefit. Safety and the possibility of clinical benefit are usually felt to be preconditions for the ethical justification for endoscopy for research in children, and we believe that these conditions were met in this study.

Biopharmaceutical considerations in paediatrics with a view to the evaluation of orally administered drug products - a PEARRL review

OBJECTIVES

In this review, the current biopharmaceutical approaches for evaluation of oral formulation performance in paediatrics are discussed.

KEY FINDINGS

The paediatric gastrointestinal (GI) tract undergoes numerous morphological and physiological changes throughout its development and growth. Some physiological parameters are yet to be investigated, limiting the use of the existing in vitro biopharmaceutical tools to predict the in vivo performance of paediatric formulations. Meals and frequencies of their administration evolve during childhood and affect oral drug absorption. Furthermore, the establishment of a paediatric Biopharmaceutics Classification System (pBCS), based on the adult Biopharmaceutics Classification System (BCS), requires criteria adjustments. The usefulness of computational simulation and modeling for extrapolation of adult data to paediatrics has been confirmed as a tool for predicting drug formulation performance. Despite the great number of successful physiologically based pharmacokinetic models to simulate drug disposition, the simulation of drug absorption from the GI tract is a complicating issue in paediatric populations.

SUMMARY

The biopharmaceutics tools for investigation of oral drug absorption in paediatrics need further development, refinement and validation. A combination of in vitro and in silico methods could compensate for the uncertainties accompanying each method on its own.

Oral drug absorption in pediatrics: the intestinal wall, its developmental changes and current tools for predictions

The dissolution, intestinal absorption and presystemic metabolism of a drug depend on its physicochemical characteristics but also on numerous physiological (e.g. gastrointestinal pH, volume, transit time, morphology) and biochemical factors (e.g. luminal enzymes and flora, intestinal wall enzymes and transporters). Over the past decade, evidence has accumulated indicating that these factors may differ in children and adults resulting in age-related changes in drug exposure and drug response. Thus, drug dosage may require adjustment for the pediatric population to ensure the desired therapeutic outcome and to avoid side-effects. Although tremendous progress has been made in understanding the effects of age on intestinal physiology and function, significant knowledge gaps remain. Studying and predicting pharmacokinetics in pediatric patients remains challenging due to ethical concerns associated with clinical trials in this vulnerable population, and because of the paucity of predictive in vitro and in vivo animal assays. This review details the current knowledge related to developmental changes determining intestinal drug absorption and pre-systemic metabolism. Supporting experimental approaches as well as physiologically based pharmacokinetic modeling are also discussed together with their limitations and challenges. Copyright © 2016 John Wiley & Sons, Ltd.

Alanyl-glutamine promotes intestinal epithelial cell homeostasis in vitro and in a murine model of weanling undernutrition

Alanyl-glutamine (Ala-Gln) has recently been shown to enhance catch-up growth and gut integrity in undernourished children from Northeast Brazil. We hypothesized that the intestinal epithelial effects of Ala-Gln in malnourished weanling mice and mouse small intestinal epithelial (MSIE) cells would include modulation of barrier function, proliferation, and apoptosis. Dams of 10-day-old suckling C57BL/6 pups were randomized to a standard diet or an isocaloric Northeast Brazil "regional basic diet," moderately deficient in protein, fat, and minerals. Upon weaning to their dam's diet on day of life 21, pups were randomized to Ala-Gln solution or water. At 6 wk of age, mice were killed, and jejunal tissue was collected for morphology, immunohistochemistry, and Ussing chamber analysis of transmucosal resistance and permeability. Proliferation of MSIE cells in the presence or absence of Ala-Gln was measured by MTS and bromodeoxyuridine assays. MSIE apoptosis was assessed by annexin and 7-amino-actinomycin D staining. Pups of regional basic diet-fed dams exhibited failure to thrive. Jejunal specimens from undernourished weanlings showed decreased villous height and crypt depth, decreased transmucosal resistance, increased permeability to FITC-dextran, increased claudin-3 expression, and decreased epithelial proliferation and increased epithelial apoptosis (as measured by bromodeoxyuridine and cleaved caspase-3 staining, respectively). Undernourished weanlings supplemented with Ala-Gln showed improvements in weight velocity, villous height, crypt depth, transmucosal resistance, and epithelial proliferation/apoptosis compared with unsupplemented controls. Similarly, Ala-Gln increased proliferation and reduced apoptosis in MSIE cells. In summary, Ala-Gln promotes intestinal epithelial homeostasis in a mouse model of malnutrition-associated enteropathy, mimicking key features of the human disease.

A revised model for electron dosimetry in the human small intestine

In this study, the absorbed dose was calculated to the small intestine (SI) wall of an adult human from electrons in its lumen contents. The effects on dose due to variations in the lumen radius and wall-thickness also were studied. The SI model was based on values gleaned from anatomic and histologic reviews of the adult human SI. Histologic and radiological analyses of the SI suggested the microscopic intricacy of this walled organ could be avoided for dosimetric purposes and a set of concentric cylinders could be used to model the SI. The model was input into the Monte Carlo N-Particle (MCNP) version 4A computational package, which was used to simulate energy deposition in the SI by electrons of fifty discrete energies ranging 10-500 keV. The source electrons as well as all resulting particles, such as knock-on electrons, bremsstrahlung, and electrons created from bremsstrahlung interactions, were transported until the particle energies fell below the 1 keV low-energy cutoff. Detailed physics treatments for secondary photons were made. With a reasonable number of histories, appropriate variance reduction techniques were used to improve the precision of the Monte Carlo calculations. The model used very small tally regions, which ranged in thickness from 0.5 microm to 200 microm depending on the electron energy studied and tally location in the wall. Relative errors associated with these calculations were maintained at less than 5%. The large number of tally results across the wall for each of the energies studied enabled the construction of the energy-specific depth dose curves in the wall. Each of these curves was consistent with the anticipated energy deposition pattern. These curves showed that only a small fraction of the energy absorbed at the contents-mucus interface reaches the stem cell layers because the cells are located deep in the mucosa. This fraction was found to vary from 1.66 x 10(-6) to 1.21 x 10(-1) over the energy range 10-500 keV. These results demonstrated the interface dose, which has been routinely reported as the "wall" dose, is a significant overestimate of the actual dose to the stem cells. The dose uncertainties associated with variations of the critical cell depth were shown to be very high for electrons whose CSDA ranges in the soft tissue exceeded the depth of the critical cells. This study showed that the uncertainty in the wall-thickness had no effect on depth doses while variation in the lumen radius significantly changes depth doses. The results suggest that these changes could be approximated by the inverse square of the lumen radius.

Pediatric celiac disease: clinicopathologic and genetic aspects

Evaluation for celiac disease (CD), an autoimmune enteropathy triggered by grain proteins in wheat, barley, rye, and possibly oats, is a common indication for pediatric endoscopy and biopsy. Duodenal or jejunal biopsy remains key for the initial diagnosis of CD. Small intestinal pathology may be diffuse or focal in CD, and histologic findings are nonspecific and must be interpreted in conjunction with clinical and serologic findings. A standardized grading system for CD biopsies is recommended. This review article summarizes the epidemiology, clinical manifestations, genetics, pathogenesis, and serologic and histologic findings of CD. Clinical management of CD and general handling of small intestinal biopsies are also addressed.

Histologic evaluation of endoscopic versus suction biopsies of small intestinal mucosae in children with and without celiac disease

BACKGROUND

Concern over the adequacy of histologic diagnosis of endoscopic duodenal biopsies in children prompted this comparative study on the histologic quality of endoscopic versus capsule biopsies. We found this problem addressed in only six previous reports.

METHODS

Blind examinations of the histologic sections of 48 duodenal biopsies obtained by gastrointestinal endoscopy in children aged 2-18 years were compared to 52 biopsies obtained by the small bowel suction method (from children aged 1-16 years).

RESULTS

Although 87.5% of endoscopic biopsies and 94.2% of capsule biopsies were adequate for histologic diagnosis, fragmentation or squashing was seen in 83.3% of endoscopic biopsies and only in 25% of capsule biopsies.

CONCLUSIONS

Biopsies obtained by suction are of better quality than those obtained by endoscopy. If endoscopy is preferred for technical reasons, the following conditions should be observed: the patients should be aged over 2 years, and a minimum of four biopsies should be obtained with forceps of a diameter greater than 2 mm. Adequate histologic criteria for diagnosis should include at least one full-thickness mucosal specimen more than 3 mm in length, vertically oriented, and not fragmented. In children under age 2, duodenal or jejunal capsule biopsies are preferred, since the specimens are usually larger and less fragmented. Endoscopy is technically more difficult in the very young patient.

Epithelial growth of the small intestine in human infants

BACKGROUND

Findings in studies in rodents have suggested that epithelial growth of the small intestine is dependent on activation of the immune system. The purpose of this study was to compare changes of postnatal epithelial growth with immunologic activity in humans.

METHODS

Duodenal biopsies were obtained by endoscopy from 74 infants. Villus area, crypt length, and mitotic count were measured, using a microdissection technique. Enterocyte height, intraepithelial lymphocytes and mucosal mast cells were recorded in histologic sections, and soluble interleukin-2 receptor levels were measured in sera. These data were compared with those from 77 adult control subjects.

RESULTS

Mean +/- SD villus area was similar in infants compared with that in adults (0.364 +/- 0.108 mm2 vs. 0.339 +/- 0.1 mm2); but mean crypt length was 31% longer (270 +/- 56 microm vs. 206 +/- 29 microm; p < 0.0001), and mitotic count was 68% higher (4.2 +/- 2.8 vs. 2.5 +/- 1 per crypt; p < 0.0001) in infants. Enterocyte height was lower during infancy (27.0 +/- 3.4 microm vs. 30.9 +/- 4.6 microm; p < 0.0001). There was no evidence of a trophic effect on the small intestine of breast feeding compared with the effect of bottle feeding. Counts of intraepithelial lymphocytes but not mucosal mast cells were significantly less in infants. Mean soluble interleukin-2 receptor levels peaked during early infancy, compared with levels in adults (1,820 +/- 596 U/ml vs. 695 +/- 359 U/ml).

CONCLUSION

These results indicate that epithelial proliferation is increased during infancy at an age when immunologic activity is high.

Morphological changes of the jejunal mucosa in protracted diarrhea and their correlation with disease duration, weight loss and serum albumin levels

The pathogenesis of protracted diarrhea is multifactorial. In developing countries, intestinal infectious processes seem to play an important role in triggering the syndrome. Thirty-four children aged 1 to 14 months, mean 6.5 months, with protracted diarrhea were studied clinically and in terms of small intestinal mucosal morphology. Mild, moderate or severe hypotrophy of the jejunal mucosa was detected in 82% of cases, and mucosal atrophy was observed in 12%. The intensity of the morphological changes of the jejunal mucosa correlated negatively with serum albumin levels. No correlation was detected between mucosal grading and duration of diarrhea or between mucosal grading and weight reported as percentile. After nutritional support was instituted, serial jejunal biopsies were obtained from 12 patients: five patients submitted to parenteral nutrition for 7 to 38 days, mean 17 days, and 7 patients receiving a hypoallergenic oral diet (semi-elemental formula, 3; chicken formula, 3; human milk, 1). In seven cases (58%) a progressive increase in villus height and a decrease in the number of inflammatory cells were noted. Recovery of the morphologic pattern was accompanied by clinical improvement in all patients.

Effect of dietary nucleotides on small intestinal repair after diarrhoea. Histological and ultrastructural changes

The effects of specific nutrients on intestinal maturation and repair after injury are practically unknown. The purpose of this work was to study the effects of dietary nucleotides on the repair of the intestinal mucosa after chronic diarrhoea induced by a lactose enriched diet in the weanling rat. One group of weanling rats was fed with a standard semipurified diet (control group), and another group was fed with the same diet containing lactose as the only soluble carbohydrate (lactose group). After 14 days the lactose group was allowed to recover for four weeks with the control diet (lactose-control group) or with the control diet supplemented with AMP, GMP, IMP, CMP, and UMP 50 mg/100 g each (lactose-nucleotide group). The control group was divided into two subgroups, which were fed with the control diet and the nucleotide supplemented diet for the same period (control-control group and control-nucleotide group). The lactose diet induced diarrhoea after 24 hours of feeding. Two weeks later there were changes in intestinal structure with loss of enterocyte microvillar surface, significant lymphocyte infiltration, supranuclear cytoplasmic vesiculation, decreased number of goblet cells, and enlarged mitochondria with low density and few cristae. After recovery from diarrhoea, animals fed the nucleotide enriched diet showed an intestinal histology and ultrastructure closer to that of the normal control group. Mitochondrial ultrastructure was closer to normal in comparison with the lactose-control diet group. In this second group the number of goblet cells as well as the villous height/crypt depth ratio was reduced and the number of intraepithelial lymphocytes increased compared with the nucleotide supplemented group. These results suggest that dietary nucleotides may be important nutrients for intestinal repair.

Dose dependent effects of protracted ingestion of small amounts of gliadin in coeliac disease children: a clinical and jejunal morphometric study

This study aimed to investigate the effects of chronic ingestion of small amounts of gliadin on children with coeliac disease. A four week challenge was performed on 20 children who had been on a gluten free diet for mean (SD) 14 (3) months. They were given a daily dose of either 100 mg (group A, n = 10, mean age 4 (2) years) or 500 mg of gliadin (group B, mean age 5 (3) years). The effects of the gliadin were monitored by morphometric study of the jejunal mucosa, intestinal permeability test with cellobiose/mannitol, and serum antigliadin antibody test. After the challenge, group A patients showed a significant increase in the mean intraepithelial lymphocyte count (before challenge 11 (3), afterwards 19 (6)) and a decrease in the villous height/crypt depth ratio (beforehand 1.5 (0.1), afterwards 1.3 (0.2)), while the intestinal permeability test remained normal and the IgA-antigliadin antibody increased in four of 10 children. After the challenge group B showed more pronounced histological changes, an increase in the mean urinary cellobiose/mannitol % (beforehand 0.028 (0.020), afterwards 0.058 (0.028)), and IgA-antigliadin antibody positivity in six of eight subjects. The discriminant analysis function showed that the pretreatment group, group A after challenge, and group B after challenge were correctly classified in 90% of cases by functions based on the individual intraepithelial lymphocyte count and the villous height/crypt depth ratio. This study shows that chronic ingestion of small amounts of gluten causes dose-dependent damage to the small intestinal mucosa in children with coeliac disease. The predictive value of laboratory tests, such as the antigliadin antibody test and the intestinal permeability test seems to be lower in treated patients than in those with active coeliac disease.

Ageing and duodenal morphometry

Small bowel morphometry was studied in 25 subjects under the age of 70 years and 22 over the age of 70. There was no evidence of malabsorption or malnutrition in either group. Two distal duodenal endoscopic biopsy specimens were examined morphometrically. There were no significant correlations between age and areas of duodenal surface epithelium, crypts and lamina propria, heights of villi and surface epithelium, depth of crypts, crypt to villus ratio, number of intraepithelial lymphocytes, duodenal architecture, enterocytes, brush border and Brunner glands. Contrary to previous reports there was no evidence for a significant effect of age on proximal small bowel morphometry.

Jejunal mucosa lymphoid cell subsets and the expression of major histocompatibility complex antigens in children

Using monoclonal antibodies with the immunoperoxidase technique the distribution pattern of class I and class II antigens of the major histocompatibility complex (MHC), and of the lymphocyte subsets have been studied in intestinal biopsies from children without mucosal lesions, from children with coeliac disease (CD) and from infants with cow's milk protein intolerance (CMPI). The staining of the intestinal mucosa for class I antigens is unaltered irrespective of the histological picture or the clinical diagnosis. Class II antigens are only partially or not expressed at all by epithelial cells in untreated coeliac disease and in some cases of cow's milk protein intolerance. The number and the composition of the lamina propria lymphocytes in both CD and CMPI are different from the normal situation. An increase of all lamina propria lymphocyte subsets is observed in untreated CD. A decrease of OKT4+ lymphocytes is observed in the lamina propria of CMPI patients. These changes may be involved in the pathogenesis of these diseases.

Jejunal mucosal morphology in healthy north Indian subjects

Morphometric measurements have been performed on small intestinal biopsy specimens obtained from 18 healthy adult Indian volunteers. The measurements were made using a computer aided measuring system, and results were similar to those previously reported for an adult Caucasian population.

Surface ultrastructure of the small intestine mucosa in children with celiac disease. I. Untreated disease and effects of long-term gluten elimination and challenge

Forty-eight gut mucosa specimens from 27 children with celiac disease, diagnosed by means of conventional serial biopsies taken at different dietary conditions, were studied by means of scanning electron microscopy (SEM). The observations were correlated with those made by concomitant dissection microscope (DM), light microscope (LM), and transmission electron microscope (TEM) examinations. Five children with constitutional short stature served as controls. The results of the SEM analyses were in good conformity with the observations made by DM, LM, and TEM. In addition, SEM was found to offer further structural variables to be analyzed. In active celiac disease and after challenge with dietary gluten, which is necessary to establish the diagnosis of children, the lesions specifically observed by SEM were (1) a strikingly uniform destruction of the villi and a distortion of the enterocytes but with preserved extrusion zones, and (2) a decrease and disruption of the glycocalyx of the enterocytes with marked irregularity of the microvilli. After successful dietary treatment and despite a normalization of the gut mucosa by routine LM, SEM often disclosed persisting lesions of the enterocytes. It was concluded that by inclusion of SEM in the routine assessments of gut biopsy specimens in children with celiac disease, the diagnostic precision becomes increased.

Surface ultrastructure of the small intestine mucosa in healthy children and adults: a scanning electron microscopic study with some methodological aspects

Biopsy specimens of light microscopically (LM) normal small intestine mucosa from eight healthy, constitutionally short-statured children without signs of gastrointestinal disease and six healthy adults were studied by scanning electron microscopy (SEM) supplemented by transmission electron microscopy (TEM). The effects on surface morphology of various preparative procedures were also investigated, using small intestine mucosa from cats and rats. Fixation with OsO4--either alone, or following glutaraldehyde fixation--markedly changed the surface ultrastructure compared to that after glutaraldehyde fixation only. By low power SEM, some differences were observed in the appearance of the small gut mucosa between adults and young children. In adults and in children above 3 years of age, the villi were usually shaped like fingers or leaves, but in infants, ridge-shaped villi predominated. The villi showed, however, a smooth surface in both infants and adults, and medium and high power SEM displayed similar pictures, irrespective of age; here the typical structural features of the normal small gut mucosa in humans were (1) distinct extrusion zones at the crests of the villi and almost no signs of enterocyte extrusion along the sides of the villi, and (2) regular enterocytes with polygonal, flat, apical surfaces covered by a thick glycocalyx that obscured the underlying microvilli.

Small intestinal mucosa in coeliac disease and cow's milk protein intolerance: morphometric and immunofluorescent studies

One hundred and twenty-five small intestinal biopsies from children with coeliac disease (CD), cow's milk protein intolerance (CMPI) and controls were compared by morphometric analysis, by counting intraepithelial lymphocytes (IEL) and by quantitative evaluation of immunoglobulin-containing cells of lamina propria. The double-stain immunofluorescent technique of Brandtzaeg and Baklien [2] was used, based on defined mucosal tissue units. A patchy enteropathy was found in 60% of CMPI, and in 14% of nonspecific changes, but never in CD. There was a significant difference in crypt depth between CD (360 +/- 80 microns) and CMPI (217 +/- 92 microns), even when lesions of equal grade were compared (P less than 0.015). IEL counts per 1000 epithelial cells showed even better discrimination between the groups (CD: 793 +/- 173, CMPI: 320 +/- 143, P less than 0.001). In CD, there was a relatively greater increase of IgM-cells (X 4.9) and of IgG-cells (X 4.2) than of IgA-cells (X 2.6). Ig-cell changes outlasted the morphological lesion in CD on a gluten-free diet. In CMPI, IgM-cells (X 2.3), IgG-cells (X 2.5), and IgA-cells (X 1.7) were proportionately increased, compared to controls. A special increase of IgE-cells in CMPI could not be substantiated. By computerized stepwise discriminant analysis based upon crypt depth, villus/crypt-ratio, IEL-count, and counts of IgM-, IgG-, IgA-containing cells of lamina propria, accurate classification of patient groups was accomplished, even when only the initial biopsy data were analysed.

Eczema and atopy in early childhood: low IgA plasma cell counts in the jejunal mucosa

Twenty-one children aged between 2 and 54 months, 14 with eczema and 7 with allergies in first-degree relatives, were referred for diagnostic jejunal mucosal biopsy for a variety of symptoms. A partial villous atrophy was found in 19 of the 21 biopsies obtained; the other 2 were normal. We report a highly significant (P less than 0.0001) lower IgA cell count in biopsies with partial villous atrophy compared with the results of our previous study of IgA and IgM plasma cells in the mucosal biopsies in children without eczema or a history of atopy matched for age and histological appearances. The IgM cell count was also lower.