Serem Freier

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.

Combination of Helicobacter pylori Strain and Tumor Necrosis Factor-?? Polymorphism of the Host Increases the Risk of Peptic Ulcer Disease in Children

Background: Helicobacter pylori infection is probably acquired in childhood and causes a vigorous immune response. It is unclear why only a subgroup of infected children develops peptic ulcer disease. We have previously reported that iceA1 strains tend to be associated with duodenal disease in children. However, the pathogenesis probably does not depend solely on the H pylori strain but also on the variability of the host response. Objectives: The aim of this study was to assess the significance of tumor necrosis factor-α (TNF-α) promoter polymorphism in relation to infection with H pylori strains in children. Methods: A total of 113 antral biopsies of H pylori–positive children (ages 2–18 years) were analyzed. Of these, 23 had duodenal disease, including erosive duodenitis and/or duodenal ulceration, and 90 had gastritis only. H pylori infection was diagnosed by bacterial culture and histology. Patient genomic DNA extracted from the antral biopsy was used to characterize the genetic polymorphism of TNF-α promoter at nucleotide positions −308 and −238 by polymerase chain reaction–based restriction fragment-length polymorphism. All H pylori strains were examined for cytotoxin-associated gene A and induced-by-contact-with-epithelium gene (iceA1). Results: A total of 31% of children with duodenal disease were infected with iceA1 positive strains and had the −238 G to A polymorphism in the TNF-α gene vs only 1.6% of children with gastritis alone (P < 0.0005). Conclusions: The combination of bacterial iceA1 and TNF-α 238 G to A polymorphism may be a risk factor for peptic ulcer disease in children infected with H pylori. Larger studies are needed to confirm this association.

Are Intraepithelial Lymphocytes in Celiac Mucosa Responsible for Inducing Programmed Cell Death (Apoptosis) in Enterocytes? Histochemical Demonstration of Perforins in Cytoplasmic Granules of Intraepithelial Lymphocytes

BACKGROUND Programmed cell death refers to the genetically determined processes by which cells die in response to physiologic extracellular and intracellular signals, morphologically described as apoptosis. In physiologic and pathologic circumstances this process may involve effector and target cells. METHODS To identify serine esterase granules in intraepithelial lymphocytes, fresh-frozen human small intestine mucosal sections from normal and celiac-affected mucosa were incubated with substrate-specific N-alpha-benzyloxy-carbonyl-L-lysine thiobenzyl (BLT) and a chromogen (4 Benzoylamino-2,5-diethoxybenzene-dazonium chloride hemi [zinc chloride] salt as capture agent and were examined by light microscopy. RESULTS Normal mucosa showed an occasional intraepithelial lymphocyte with BLT-positive intracytoplasmic granules. Some large mononuclear cells of the lamina propria were similarly stained. Many more intraepithelial lymphocytes were BLT-positive among the surface enterocytes of untreated celiac mucosa. Lamina propria mononuclear cells close to the basal layer of crypt cells also appeared to be increased. CONCLUSIONS The histochemical identification of BLT-positive esters within intraepithelial lymphocytes suggests their involvement in enterocyte death under physiologic conditions. The increased BLT-positive intraepithelial lymphocytes found in the celiac mucosa may be related to the known increase in cytotoxic intraepithelial lymphocytes in untreated celiac disease.

The Effect of Immediate-Type Gastrointestinal Allergic Reactions on Brush Border Enzymes and Gut Morphology in the Rat

ABSTRACT: The aim of the present study was to create clearly documented immediate-type allergy to food protein in the intestine of rats and to study some pathophysiological phenomena induced by challenge with the allergen. To achieve this, rats were sensitized with ovalbumin. A passive cutaneous anaphylaxis reaction to ovalbumin was negative in all controls and positive in all test animals when Bordetella pertussis was used as adjuvant. Sixty minutes after an intravenous injection of 125I-human serum albumin and 45 min after an ovalbumin challenge, given by gavage, the rats were sacrificed. The intestine was removed and sections taken for morphologic studies. The remainder was rinsed, opened, cut into measured segments, weighed, and the radioactivity was measured. Disaccharidases, alkaline phosphatase, and protein were estimated in homogenates of epithelium. Results in both control and test animals showed that radioactivity decreased as one moved distally along the intestine. However, radioactivity was significantly higher (p < 0.01) in the intestine of test animals than in controls. Radioactivity in liver, kidney, spleen, and lungs was identical in test and control animals. There was significant reduction in levels of alkaline phosphatase (p varied from < 0.05 to < 0.001), maltase (p < 0.05), and sucrase (p < 0.05 to < 0.01). Lactase activity in contrast was significantly raised (p < 0.05). There was no change in intestinal morphology or in the intestinal mast cell count.

Relative expression and localization of the insulin-like growth factor system components in the fetal, child and adult intestine.

Background: The insulin-like growth factors (IGFs) are important in the development and maintenance of the gastrointestinal tract. Objectives: To compare the expression of IGFs and their receptors in the stomach and duodenum of the fetus, the child and the adult. To identify the cells mainly responsible for the production of the members of the IGF system. Methods: Tissue was obtained from fetus after abortion and from children and adults during diagnostic endoscopy and biopsy. The expression of the IGFs and their receptors was estimated by an RNAse protection assay and sections were stained with antisera to the components of IGF system. Results: The tissues from the stomach and the duodenum expressed the two IGFs and their receptors at all stages of life. The fetal IGF receptors I and II, were approximately ten times higher than in the child and IGF-II was five times higher. Immunohistochemical staining showed the components of the IGF system to be localized to the gastric glands and to the basotlateral border of the gastric epithelial cells. In the duodenum, they were concentrated at the apical portion of the epithelial tissue. They could also be identified in ganglion cells and nerves. Conclusions: The IGFs and their receptors in the stomach and duodenum are expressed in all age groups and mostly are highest in the fetus. The IGF system proteins were located in the gastric glands and epithelium and in the apical portion of the villous epithelium of the duodenum.

A study of stimuli operative in the release of antibodies in the rat intestine.

We describe here a series of experiments which have been undertaken in the course of several years to try and study secretory mechanisms operative in the release of antibodies in the lumen of the intestine. The results of our experiments suggest that there are a number of stimuli that are efficacious in eliciting antibody release in the lumen of the rat intestine. These include the peptide hormones cholecystokinin and substance P, and cholinergic agonists such as pilocarpine. The fact that food has a similar effect indicates that the stimulation of antibody release is a physiological process co-ordinated with the ingestion of foreign antigens. We have also shown that food mediates its effect by means of cholecystokinin. Cholecystokinin promotes the release of antibodies belonging to the IgA, IgG, IgM and IgE isotypes. There is reason to believe that not all the IgA is secretory IgA. Antibody release can be inhibited by the CCK antagonist proglumide and by cholinergic antagonists. The intracellular messengers that participate in this process are changes in cytosolic calcium. It is proposed that the release of antibodies in the gastrointestinal tract is an active secretory process.

Absorption of medium chain triglycerides in the stomach of the human infant.

Following previous observations that medium chain triglycerides (MCT) are absorbed from the stomach of suckling rats, this study was devoted to studying absorption of MCTs in human infants. Four groups of patients were studied: (a) infants suffering from pyloric stenosis, (b) premature infants, (c) children suffering from cystic fibrosis, (d) infants with miscellaneous conditions. Infant formulae with known amounts of MCT were introduced by gastric tube and samples were removed at 0, 20, 40, and 60 min. In patients with pyloric stenosis there was an 18.1% decrease in MCT during the first 20 min. No significant changes in MCT took place during the subsequent 40 min. A similar response was observed in the group of premature infants. Older infants with miscellaneous diagnoses and children with cystic fibrosis showed an even rate of disappearance of MCT during the 60-min test period, and approximately 30% of the original MCTs present disappeared during this period. We conclude that MCTs are absorbed in the stomach of infants and children. Absorption appears to improve with age. Because MCT are an important constituent of formulae for premature infants and children with defects of small intestinal digestion and absorption of fat, these observations have practical implications.

Gastric Handling of Medium-Chain Triglycerides and Subsequent Metabolism in the Suckling Rat

We have previously shown that preduodenal lipases account for 50% of the lipolytic capacity of 14-day-old rats. The present investigation was designed to study the kinetics of and optimal conditions for absorption of fat in the stomach of suckling rats and its subsequent distribution in the body. After the simultaneous instillation of medium-chain triglycerides (MCT) containing 1.25 microCi 2,3-[3H]trioctanoate and of long-chain triglycerides containing 1.25 microCi 1-[14C]glycerol trioleate into the stomach ligated at the pylorus, we were able to show that gastric absorption of fat is limited to MCT. Two and a half minutes after injection, 88.6% of the radioactivity in the wall of the stomach was associated with free fatty acids, proving that lipolysis had preceded the absorption of the majority of the MCT. The remainder of the radioactivity was found in mono-, di-, and triglycerides as well as with cholesterol ester and phospholipids. In the plasma, peak radioactivity was attained within 2.5 min and a steady state ensued which lasted at least 30 min. Over this time period, specific radioactivity continued to rise in the liver, suggesting that hepatic uptake proceeded at the same rate as gastric absorption. Uptake could also be demonstrated in the three other organs tested, the lungs, the heart, and the kidneys. Absorption of MCT at pH 3 was only 20% of absorption at pH 6, which is the physiological pH in the suckling rat stomach within the first 10 min after a feed. Both at pH 3 and at pH 6, the addition of sodium taurocholate increased absorption of MCT over threefold. It is likely that the absorption of MCT by the stomach is a physiological event in the suckling rat.

Substance P Accelerates Secretory Component-Mediated Transcytosis of IgA in the Rat Intestine

We have previously shown that cholecystokinin (CCK) causes secretion of specific IgA antibodies in the rat intestine.1 The objective of the experiments described below was to establish if another gut-brain peptide, substance P (SP), also accelerates secretion of IgA. The reason for choosing this peptide was that SP is functionally similar to CCK, though chemically quite unrelated. Once having established that SP, indeed, causes secretion of IgA specific antibodies, we proceeded to obtain data on the molecular size of the IgA, on its probable mode of transport and on the absolute amounts secreted.

Rise of Prostanoids in Rat Small Intestinal Mucosa following Intestinal Protein Hypersensitivity

ABSTRACT.: The purpose of the present study was to establish whether there is an elevated prostaglandin concentration in the intestinal mucosa in rats suffering from an immediate type hypersensitivity reaction. Rats of the Hooded-Lister strain were sensitized and challenged with ovalbumin. Control rats were given adjuvant only. Prostanoid content of scraped mucosa was determined by radioimmunoassay. It was found that the prostaglandin E2 content in the sensitized intestine was significantly elevated as compared to the controls. There was no significant rise of 6-keto prostaglandin Fα or thromboxane E2 in the sensitized rats. These results show that prostaglandin B2 participates in intestinal immediate type responses and may explain some of the clinical manifestations of food protein allergy.