Gastric metaplasia and duodenal ulcer disease in children infected by Helicobacter pylori

Gastric metaplasia of the duodenal mucosa in Crohn's disease: novel histological and endoscopic findings

Background and study aims  Upper gastrointestinal endoscopy and biopsy are useful for differential diagnosis of Crohn's disease (CD) of the large intestine and ulcerative colitis (UC). We aimed to identify novel histopathological and endoscopic findings in the upper gastrointestinal tract in patients with CD who did not have Helicobacter pylori infection. Patients and methods  Upper gastrointestinal endoscopy was performed on patients with CD and UC. Mucosal lesions detected were subsequently observed using magnifying endoscopy with narrow-band imaging (M-NBI), following which biopsy was performed. When no mucosal lesion was detected on conventional endoscopy, M-NBI and biopsy were performed on four sites: the gastric body, gastric antrum, duodenal bulb, and second portion of the duodenum. Results  The prevalences of gastric metaplasia (GM) were 48 % (24/50) and 16 % (8/50) in the CD and UC groups, showing a significant difference ( P  = 0.001). In 23 of 24 patients with histologically proven GM in the CD group, mucosal lesions were detected using conventional white-light imaging (C-WLI). In 22 of 24 patients with histologically proven GM in the CD group, disappearance of normal villous structure and the presence of curved marginal crypt epithelium were noted using magnifying endoscopic findings characteristic of GM (M-GM). A combination of C-WLI and M-NBI yielded a significantly increased specificity ( P  = 0.004) and accuracy ( P  = 0.039). Conclusions  The prevalence of GM in the duodenal mucosa was significantly higher in patients with CD than in controls. The identified endoscopic findings may be useful as novel indicators for the histological diagnosis of GM in the duodenum.

Loss of Lrig1 leads to expansion of Brunner glands followed by duodenal adenomas with gastric metaplasia

Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) is a pan-ErbB negative regulator and intestinal stem cell marker down-regulated in many malignancies. We previously reported that 14 of 16 Lrig1-CreERT2/CreERT2 (Lrig1(-/-)) mice developed duodenal adenomas, providing the first in vivo evidence that Lrig1 acts as a tumor suppressor. We extended this study to a larger cohort and found that 49 of 54 Lrig1(-/-) mice develop duodenal adenomas beginning at 3 months. Most adenomas were histologically low grade and overlaid expanded Brunner glands. There was morphologic and biochemical blurring of the boundary between the epithelium and Brunner glands with glandular coexpression of ErbB2, which is normally restricted to the epithelium, and the Brunner gland marker Mucin6. Some adenomas were high grade with reduced Brunner glands. At age 4 to 5 weeks, before adenoma formation, we observed enhanced proliferation in Brunner glands and, at 2 months, an increase in the size of the Brunner gland compartment. Elevated expression of the epidermal growth factor receptor (Egfr) ligands amphiregulin and β-cellulin, as well as Egfr and phosphorylated Egfr, was detected in adenomas compared with adjacent normal tissue. These adenomas expressed the gastric-specific genes gastrokine1 and mucin5ac, indicating gastric metaplasia. Moreover, we found that a subset of human duodenal tumors exhibited features of LRIG1(-/-) adenomas, including loss of LRIG1, gastric metaplasia (MUCIN5AC and MUCIN6), and increased amphiregulin and Egfr activity.

Role of childhood infection in the sequelae of H. pylori disease

The persistence of Helicobacter pylori infection plays a fundamental role in the development of H. pylori-associated complications. Since the majority of infected persons acquire the bacteria during early childhood, an examination of the immunobiology of H. pylori infection in children compared with that of adults may help identify host factors that contribute to persistent infection. Therefore, we begin our review of the role of persistence in H. pylori disease with an assessment of the clinical features of H. pylori infection in children. We next review the bacterial factors that promote colonization and evasion of host defense mechanisms. We then focus our attention on the early host immunological factors that promote persistence of the infection and its complications in humans and mouse models. We also highlight topics in which further research is needed. An examination of how immunological factors cause divergent manifestations of H. pylori infection in children compared with adults may provide new insight for therapeutic modification or prevention of persistent H. pylori infection and its complications.

Helicobacter pylori infection and duodenal gastric metaplasia in healthy young adults

BACKGROUND/AIMS

Duodenal ulcers occur relatively frequently in adolescents, like in adults, and may relate to Helicobacter pylori infection and duodenal gastric metaplasia (DGM). This study investigated the association between H. pylori infection and DGM in healthy adults aged 20-29.

METHODS

Between 1995 and 2005, endoscopic biopsies of the duodenum, antrum and body were taken from healthy, young volunteers, who were first-year medical students, faculty staff, residents, and research assistants of Gyeongsang National University in Jinju, Korea. Urease tests were performed and the extent of DGM and histopathological grades according to the Updated Sydney System were determined.

RESULTS

In total, 662 subjects were enrolled (429 males and 233 females). The median age was 22.3 years. The overall incidence of DGM was 11.5% but DGM was more frequent in males (15.4%) than in females (4.3%) (p<0.0001). While H. pylori positivity rates changed significantly during the 1995-2005 period (p<0.01), the incidences of DGM did not. DGM was observed in 7.2% and 14.9% of subjects who were and were not colonized with H. pylori, respectively. DGM was also associated with less severe chronic gastritis and the absence of active gastritis in both the antrum and body, and the absence of follicles in the antrum (p<0.05).

CONCLUSIONS

These findings suggested that DGM is not rare in healthy young adults and is unrelated to gastric H. pylori infection.

Effect of Helicobacter pylori infection on gastric acid secretion and meal-stimulated serum gastrin in children

BACKGROUND

Comparative studies of gastric acid secretion in children related to Helicobacter pylori infection are lacking. The purpose of this study was to compare acid secretion and meal-stimulated gastrin in relation to H. pylori infection among pediatric patients.

MATERIALS AND METHODS

Thirty-six children aged 10-17 years (17 with H. pylori infection) undergoing diagnostic endoscopy participated in the study. Diagnoses included gastritis only (n = 23), duodenal ulcer (n = 5) and normal histology (n = 8). Gastric acid output was studied using the endoscopic gastric secretion test before and 2-3 months after H. pylori eradication. Meal-stimulated serum gastrin response was assessed before and 12 months after eradication.

RESULTS

H. pylori gastritis was typically antrum-predominant. Acid secretion was greater in H. pylori-positive patients with duodenal ulcer than in gastritis-only patients or controls [mean +/- standard error (SE): 6.56 +/- 1.4, 3.11 +/- 0.4 and 2.65 +/- 0.2 mEq/10 minutes, respectively; p <.001]. Stimulated acid secretion was higher in H. pylori-positive boys than girls (5.0 +/- 0.8 vs. 2.51 +/- 0.4 mEq/10 minutes, respectively; p <.05). Stimulated acid secretion pre- and post-H. pylori eradication was similar (5.47 +/- 0.8 vs. 4.67 +/- 0.9 mEq/10 minutes, respectively; p =.21). Increased basal and meal-stimulated gastrin release reversed following H. pylori eradication (e.g. basal from 134 to 46 pg/ml, p <.001 and peak from 544 to 133 pg/ml, p <.05).

CONCLUSIONS

H. pylori infection in children is associated with a marked but reversible increase in meal-stimulated serum gastrin release. Gastric acid hypersecretion in duodenal ulcer remains after H. pylori eradication, suggesting that the host factor plays a critical role in outcome of the infection.

Burden of Helicobacter pylori and H. pylori-related diseases in developed countries: recent developments and future implications

Helicobacter pylori colonizes the gastric mucosa. H. pylori infection is the main cause of peptic ulcer and gastric malignancy. This review gives an overview on the epidemiology of H. pylori infection and H. pylori-associated diseases in the developed world, mainly Europe, and it discusses very recent developments with regard to the prevalence and its future implications for H. pylori-associated diseases.

Helicobacter pylori infection induces duodenitis and superficial duodenal ulcer in Mongolian gerbils

BACKGROUND

There is no direct evidence for an animal model of Helicobacter pylori induced duodenal ulcer.

AIM

In this study we evaluated the roles of bacterial strain and age of experimental animals in induction of duodenitis and duodenal ulcer in Mongolian gerbils after H pylori infection.

METHODS

Specific pathogen free Mongolian gerbils were inoculated orally with three bacterial strains (H pylori ATCC 43504, TN2GF4, and K-6, a clinical isolate from a patient with gastric cancer in our clinic). These strains have both the cagA gene and VacA. Five week old gerbils were used to emulate prematurity infection and 14 week old animals were used as mature test subjects. Animals were observed for 12 weeks after inoculation. Interleukin 8 (IL-8) production in gastric epithelial cells (MKN74) after coculture with the H pylori strains was measured by ELISA.

RESULTS

Gastritis and gastric ulcers were found in all gerbils infected with the three strains. However, duodenitis and gastric metaplasia were seen more frequently in gerbils infected with TN2GF4 and K-6 strains than in the ATCC 43504 infected or control groups (p<0.05). Superficial duodenal ulcers with severe duodenitis and gastric metaplasia were found in two gerbils inoculated at 14 weeks with the TN2GF4 strain but none at five weeks. The TN2GF4 strain stimulated significantly higher levels of IL-8 than ATCC 43504 and K6 strains (p=0.0039).

CONCLUSIONS

When injected into adult Mongolian gerbils, a specific strain (TN2GF4) of H pylori can induce duodenitis with gastric metaplasia and superficial duodenal ulcers. Induction of duodenal ulcer in an animal model fulfills the requirements of Koch's postulates for establishing a role for H pylori as a causative agent.

Metaplasia of the duodenum shows a Helicobacter pylori-correlated differentiation into gastric-type protein expression

The origin of gastric metaplasia of the duodenum (GMD) remains enigmatic. We studied expression of mucins and trefoil peptides in GMD to gain insight into its phenotype and origin. We examined duodenal tissue of 95 patients (0 to 83 years old, 26 with gastric Helicobacter pylori infection) for the presence of GMD. Expression was examined immunohistochemically of secretory mucins (MUC2, MUC5AC, MUC5B, and MUC6), trefoil peptides (TFF1, TFF2, and TFF3), and sucrase-isomaltase (SI). GMD, found in 37 patients, correlated positively to gastric H. pylori infection, age, and villus atrophy. MUC2 and TFF3, expressed in normal goblet cells, were absent from 100% and 87% of GMD, respectively. GMD ubiquitously expressed MUC5AC, whereas MUC5AC expression in adjacent goblet cells was closely correlated with the extent of GMD. TFF1, TFF2, and MUC6 were found in 84%, 92%, and 65% of GMD, respectively. MUC5B was absent from epithelium and GMD. SI, expressed by villus enterocytes, was absent from GMD. Brunner's glands ubiquitously expressed MUC5B, MUC6, and TFF2. GMD was characterized by the expression of gastric-type proteins MUC5AC, MUC6, TFF1, and TFF2 and the absence of intestinal markers MUC2, TFF3, and SI. In terms of the location of metaplastic cells, our results suggest that epithelial cells migrating toward villus tips switch to gastric-type secretory cells. Positive correlation with infection suggests an inductive role H. pylori in the development of GMD.

Decreased epithelial cytokine responses in the duodenal mucosa of Helicobacter pylori-infected duodenal ulcer patients

Helicobacter pylori colonizes the human stomach and areas of gastric metaplasia in the duodenum, but only a minority of those that are infected develop symptoms, e.g., peptic ulcers. Although most ulcers occur in the duodenum, almost all studies of mucosal immune responses against the infection have been limited to responses in the stomach. In the present study we evaluated whether there are differences in the levels of proinflammatory cytokines as well as immunoregulatory cytokines in the duodenal mucosa of duodenal ulcer (DU) patients and asymptomatic (AS) carriers which may be related to the development of duodenal ulcers. Duodenal biopsy specimens collected from normal mucosa as well as metaplastic mucosa of DU patients, AS carriers, and uninfected controls were analyzed for a number of cytokines by immunohistochemistry. Interestingly, the level of epithelial staining for several cytokines, e.g., interleukin-8 (IL-8), transforming growth factor beta (TGF-beta), and gamma interferon (IFN-gamma), was found to be significantly lower in DU patients than in AS carriers and uninfected individuals. No differences were observed when cytokine staining in normal and metaplastic biopsy specimens was compared. However, larger numbers of IL-8-, IL-6-, TGF-beta-, and IFN-gamma-positive mononuclear cells were observed in the duodenal lamina propria of both DU patients and AS carriers than in that of the uninfected controls. Our finding that a number of cytokines that may be important for the mucosal host defense against H. pylori are strongly decreased in the duodenal epithelium of ulcer patients suggests that a down-regulated immune response plays a role in the development of duodenal ulcers.

Autonomic nervous activity before and after eradication of Helicobacter pylori in patients with chronic duodenal ulcer

BACKGROUND

Helicobacter pylori infection is involved in the formation of chronic peptic ulcer. However, a previously reported hypothesis concerning the involvement of central autonomic nervous disorder in this condition cannot be ruled out.

AIM

To use spectrum analysis of heart rate viability to examine autonomic nervous activity before and after H. pylori eradication.

METHODS

Twenty patients with chronic duodenal ulcer (duodenal ulcer group) and 20 age-matched normal adults (N group). In both groups, 24-h Holter electrocardiograms (ECGs) were recorded and spectrum analysis of heartrate variability was performed. In the duodenal ulcer group, Holter ECG was recorded before and after H. pylori eradication.

RESULTS

In the N group, analysis of heart rate variability showed that high frequency (HF) power, an index of parasympathetic activity, was high at night, while the low frequency (LF)/HF ratio, an index of sympathetic function, was high during the daytime. In the duodenal ulcer group, HF power was higher at night than during the daytime, showing a similar pattern to the N group, but the power value was higher than in the N group (P < 0.05). In the duodenal ulcer group, LF/HF at night was significantly higher than that of the N group. In addition, in the duodenal ulcer group, autonomic activity after H. pylori eradication did not differ significantly from that before H. pylori eradication.

CONCLUSIONS

In patients with chronic peptic ulcer, both sympatheticotonia and parasympatheticotonia may occur at night, and this abnormality in autonomic nervous activity may cause increased gastric acid secretion and gastric mucosal vasoconstriction. Abnormalities in autonomic activity persist even after H. pylori eradication, suggesting that they may be an independent risk factor in the formation of chronic peptic ulcer in addition to H. pylori infection.

Prevalence of gastric metaplasia in the duodenal bulb is low in Helicobacter pylori positive non-ulcer dyspepsia patients

BACKGROUND

Gastric metaplasia in duodenum is a common phenomena in duodenal ulcer patients. However, the role of gastric metaplasia in patients with non-ulcer dyspepsia is not clear. It is not known either whether Helicobacter pylori infected non-ulcer patients who are CagA-seropositive have gastric metaplasia in duodenum more often than CagA-negative patients.

AIMS

To compare prevalence of gastric metaplasia in duodenum in non-ulcer dyspepsia patients according to Helicobacter pylori status.

PATIENTS AND METHODS

A series of 400 unselected dyspeptic patients in primary care were investigated. Patients with no endoscopic evidence of organic disease (n=236) were enrolled in the study. Duodenal bulb and gastric biopsies were collected, as well as blood samples for Helicobacter pylori determination.

RESULTS

There were no differences between CagA-seropositive and -seronegative Helicobacter pylori infected patients as far as concerns gastric metaplasia in duodenal bulb (20% vs 25%). Helicobacter pylori negative non-ulcer patients more often had gastric metaplastic changes (46%, p<0.0001) in duodenum.

CONCLUSION

Helicobacter pylori infection has no major role in development of gastric metaplasia in duodenal bulb in non-ulcer dyspeptic patients. Furthermore, it does not result in positive CagA-serology, an increased risk for gastric metaplasia compared with CagA-seronegative cases.

Increased macrophage infiltration of gastric mucosa in Helicobacter pylori-infected children

The purpose of the study was to quantify gastric mucosal macrophages and define their association with the histopathologic features of stomach biopsies obtained from Helicobacter pylori-infected and uninfected children. Endoscopically obtained gastric biopsies from symptomatic children were independently evaluated by two groups of pathologists. Thirty children were evaluated; 14 were H. pylori-infected. H. pylori positivity was determined by hematoxylin and eosin (H&E), Giemsa, Warthin-Starry and an H. pylori-specific immunoperoxidase stain. A macrophage-specific, KP-1, immunoperoxidase stain was used to quantify positive cells. Inflammatory cell infiltrates were graded by severity with scores of mild to severe. Increased numbers of gastric mucosal macrophages were observed in biopsies of H. pylori-infected versus uninfected children (P < 0.05) and correlated with gastritis severity. The role of this inflammatory cell the in persistence of gastric mucosal inflammation in H. pylori infection warrants further study to develop targeted immunotherapeutic strategies.

The pathogenesis of duodenal gastric metaplasia: the role of local goblet cell transformation

BACKGROUND AND AIMS

Gastric metaplasia is frequently seen in biopsies of the duodenal cap, particularly when inflamed or ulcerated. In its initial manifestation small patches of gastric foveolar cells appear near the tip of a villus. These cells contain periodic acid-Schiff (PAS) positive neutral mucins in contrast with the alcian blue (AB) positive acidic mucins within duodenal goblet cells. Previous investigations have suggested that these PAS positive cells originate either in Brunner's gland ducts or at the base of duodenal crypts and migrate in distinct streams to the upper villus. To investigate the origin of gastric metaplasia in superficial patches, we used the PAS/AB stain to distinguish between neutral and acidic mucins and in addition specific antibodies to immunolocalise foveolar cell mucin MUC5AC, the foveolar cell secretory product, gastric trefoil factor (TFF1), the mature goblet cell mucin MUC2, and MUC2 core antigen.

RESULTS

Cells in focal patches of gastric metaplasia contained secretory granules of both gastric and goblet cell phenotypes. MUC5AC and TFF1 were present as expected in gastric foveolar cells but in addition, MUC2 core antigen, normally present only in the Golgi of intestinal goblet cells, was expressed in secretory granules. Goblet cells in the vicinity of metaplastic patches also expressed both gastric and intestinal antigens. MUC5AC/MUC2 containing goblet cells were most common near the villus tip but were also seen at the base of crypts. Where crypts and Brunner's gland ducts merged they were always seen on the crypt side of the junction. Goblet cells were the only cells to express gastric antigens in these areas. In advanced metaplastic lesions, dual phenotype goblet cells were less evident and fewer cells expressed intestinal mucin antigens.

CONCLUSIONS

We suggest that goblet cells that express both intestinal and gastric antigens may represent local precursors of gastric metaplasia undergoing a transition to foveolar-like cells of mixed phenotype at the site of early metaplastic patches. As metaplasia becomes more widespread, a more pure gastric phenotype emerges. This progression is likely to be controlled by local inflammatory signals.

Gastric metaplasia: a frequently overlooked feature of duodenal biopsy specimens in untreated celiac disease

BACKGROUND

Duodenal gastric metaplasia is rarely reported in untreated celiac disease, although it is seen in 60% to 100% of duodenal biopsy specimens in nonceliac patients with histologic duodenitis. The low incidence could represent underreporting, a decreased incidence in pediatric patients generally, or the more distal sampling site that is customary for most biopsy specimens that are obtained to diagnose celiac disease. It could also be a unique feature of the inflammatory reaction that characterizes this disease. The purpose of this study was to examine the incidence of gastric metaplasia in duodenal specimens from children with untreated celiac disease with special reference to patient age and biopsy site.

METHOD

Formalin-fixed paraffin-embedded specimens of duodenal mucosa were selected from the pathology department's archival material. Sections were either stained histochemically or by immunochemical methods, according to an antigen-retrieval protocol. Forty-four duodenal specimens from untreated patients with celiac disease (n = 22) and control subjects of similar age with normal histology (n = 22) were examined. Ten of each were obtained during upper endoscopy from the proximal duodenum (proximal site) and 12 of each by Crosby capsule near the ligament of Treitz (distal site).

RESULTS

All specimens from patients with celiac disease exhibited marked villous atrophy. None had been noted to have gastric metaplasia during routine examination of sections stained by hematoxylin and eosin. Fifteen (68%) of 22 of the celiac specimens and 2 of 22 (9%) control specimens contained gastric metaplasia, identified as patches of gastric-type cells containing MUC5AC (gastric mucin), pS2 (gastric trefoil factor) and neutral (periodic acid-Schiff-positive) mucin. Five of the seven celiac specimens that had no metaplasia showed increased numbers of goblet cells expressing gastric markers. The incidence of gastric metaplasia was not different for endoscopic (70%) or capsule (67%) specimens. Sixty-eight percent (7/11) of patients aged less than 3 years had gastric metaplasia.

CONCLUSION

The presence of gastric metaplasia has been previously underreported in celiac disease specimens. Detection would be improved by the routine use of period acid-Schiff/ alcian blue staining. The incidence of gastric metaplasia in celiac disease is not significantly influenced by biopsy site or age at time of the biopsy.

Chronic gastrointestinal inflammation

Chronic gastrointestinal inflammation is one of the most common types of inflammatory process which affects humans. It is diverse in aetiology, pathogenesis and manifestation. There are also features of chronic inflammation at different sites within the gastrointestinal tract which provide a common thread in terms of the approaches which may be used in investigating these intriguing processes. This paper provides an overview of the mucosal changes in chronic gastrointestinal inflammation. Conserved and variable features of inflammation at different sites extending from the oral cavity to the rectum are highlighted. The involvement of different inflammatory cell types within any diagnostic entity is considered and the progression from an acute to chronic inflammatory condition explored. Important issues in the maintenance of a chronic inflammatory state are the balance between pro- and anti-inflammatory pressures, the driving force behind the inflammation and immune response that is occurring and the mechanisms for curtailment of unwanted or harmful responses which may damage the host. Thus inflammation is likely to result when there is persistence of a driving force and/or imbalance in the pro- and anti-inflammatory mechanisms in the tissue involved.

Effect of Helicobacter pylori eradication on the natural history of duodenal ulcer disease

BACKGROUND

Duodenal ulcer disease is strongly associated with Helicobacter pylori infection of the gastric mucosa. Eradication of H pylori from the gastric mucosa in adults is associated with long term healing of ulcers.

AIMS

To follow a cohort of children with duodenal ulcer disease for a minimum of two years after the eradication of H pylori.

PATIENTS AND METHODS

Over a three year period, all children diagnosed with duodenal ulcer disease had their symptoms documented and their H pylori status evaluated. The histories of these children were carefully screened to determine previous symptoms and to document previous treatment regimens.

RESULTS

Sixteen children were diagnosed with ulcers and 15 were available for treatment and long term follow up. The median age at which symptoms first occurred was 10.5 years (range, 6-14) and the median duration of symptoms was 24 months (range, 2-60). Ten of the children had been treated with H2 receptor antagonists for a median of 3.5 months (range, 1-60). Duodenal ulcers healed in all children after eradication of H pylori and all children have remained asymptomatic for a median of 37 months (range, 26-62). No child has required subsequent admission to hospital.

CONCLUSION

Eradication of H pylori is very effective in the long term healing of duodenal ulcer disease. H pylori eradication should be the standard treatment for all infected children who present with duodenal ulcer disease.

Gastric ulcer, atrophic gastritis, and intestinal metaplasia caused by Helicobacter pylori infection in Mongolian gerbils

BACKGROUND

Helicobacter pylori infection is associated with gastroduodenal disease in humans. In this study we aimed to show this relationship directly in Mongolian gerbils.

METHODS

The animals were challenged orally with H. pylori and killed 1, 2, 3, and 6 months after inoculation for histologic and anti-H. pylori antibody titer examination.

RESULTS

The spiral bacteria were observed in the mucus and gastric pits of all infected animals. A severe infiltration of the lamina propria by polymorphonuclear and mononuclear cells was seen 1 month after H. pylori inoculation. The submucosa was infiltrated by mainly mononuclear cells with formation of lymphoid follicles. Erosion of the gastric mucosa appeared soon after inoculation, whereas gastric ulcers, gastritis cystica profunda, and atrophy with goblet cell metaplasia occurred between 3 and 6 months after inoculation. In the duodenal mucosa a mild inflammatory cell infiltration with ballooning and diminished number of duodenal glands was seen. The IgG anti-H. pylori antibody titer increased gradually after 2 months of inoculation.

CONCLUSIONS

Since the gastritis, gastric ulcers, atrophic gastritis, and intestinal metaplasia that developed in Mongolian gerbils were similar to those observed in humans, this model may be useful to study the therapy of gastric ulcer and, with a longer observation period, to confirm a possible relationship between H. pylori and malignancy.

Histologic findings and Helicobacter pylori in duodenal biopsies

We have studied the morphologic aspects of the duodenal bulb in relation to Helicobacter pylori infection in a large group of patients with endoscopically assessed duodenitis to learn more about the pathogenesis of nonspecific duodenitis (bulbitis) and to clarify the specific role of H. pylori. Eight duodenal biopsy specimens in the four quadrants of the first part of the bulb and four gastric antral biopsy specimens were taken in 208 patients. Specimens were fixed in formalin, or in glutaraldehyde, then slides were stained with hematoxylin and eosin, periodic acid-Schiff, and Alcian-Giemsa, and with toluidine blue for semithin sections. Duodenal histology revealed inflammation in 155 (74.5%) and H. pylori-like bacterial bodies in 153 (73.5%) of the patients; H. pylori infection in the gastric antrum was diagnosed in 173 (83.1%) of the patients. Distinguishing histologic aspects appeared to be related to the presence of H. pylori infection. We believe that the present histologic grading of duodenitis correlates better with the natural history of H. pylori infection in the duodenal bulb, and better fits the requirements of a modern classification than the classification commonly used in duodenitis. We conclude that the term H. pylori-linked bulbitis should be adopted as the proper term to identify the particular kind of duodenitis predisposing to peptic ulcer.

Carbon 13-labeled urea breath test for the diagnosis of Helicobacter pylori infection in children

Helicobacter pylori infection is mainly acquired in childhood, and studies on the epidemiology of this infection depend on the availability of a noninvasive diagnostic test for use in children. The aim of this study was to determine whether the carbon 13-labeled urea breath test (UBT) can be used in children by evaluating: (1) its sensitivity and specificity compared with either culture or both rapid urease test and histologic examination, (2) whether a test meal or a prolonged fast is required, (3) the usefulness after treatment for H. pylori. Eighty-eight children (mean age, 10.6 +/- 4.19 years) who were undergoing upper endoscopy were studied while fasting, not fasting, and after treatment. Children were given 50 mg of 13C-urea if they weighed less than 50 kg or 75 mg of 13C-urea if they weighed more than 50 kg with 50 mg of a glucose polymer solution in 7.5 ml of water. Breath samples were collected at baseline and at 15, 30, 45, and 60 minutes. In 63 fasting children the UBT was 100% sensitive and 97.6% specific at 30 minutes with a cutoff value of 3.5 delta 13CO2 per mil. Nonfasting tests in 23 children, performed between 1 and 2 hours after their usual meal, were 100% sensitive and 91.6% specific. In 13 children fed directly before the UBT, the sensitivity of the test was reduced to 50%. Thirty minutes was the optimal sampling time. There was a significant decrease in specificity when samples were obtained at 15 minutes, possibly caused by the interference of oral urease-producing organisms. The test was 100% sensitive and specific in 20 children after treatment for H. pylori infection. The UBT is a highly sensitive and specific test for the diagnosis of H. pylori infection in children. Neither a prolonged fast nor a test meal is required.

Promotion of ulcerative duodenitis in young ferrets by oral immunization with Helicobacter mustelae and muramyl dipeptide

BACKGROUND

The purpose of this study was to determine whether oral immunization of ferret kits with a whole-cell sonicate of Helicobacter mustelae lysate (Hml) and the adjuvant muramyl dipeptide (MDP) would reduce the incidence of natural colonization with H. mustelae and the extent of Helicobacter-associated gastritis by enhancing the host mucosal immune response.

MATERIALS AND METHODS

Between the ages of 4 and 11 weeks, 44 ferret kits were gavaged with Hml and various doses of MDP. The extent of gastritis and duodenitis and the immune response to H. mustelae were evaluated.

RESULTS

All kits became colonized naturally with H. mustelae and the majority developed mild to severe gastritis and duodenitis. Kits that received Hml with MDP developed significantly greater inflammation of the gastric antrum and duodenum, as compared to kits vaccinated with Hml alone. Vaccination with Hml and 50 micrograms of MDP was associated with severe lesions in the proximal duodenum characterized by accumulation of mononuclear inflammatory cells, mucosal erosion, and ulceration. Although serum antibody specific for H. mustelae in 4-week-old kits was approximately 50% of adult levels, a finding attributable to passively acquired maternal antibody, both systemic and mucosal antibody levels became depressed over time despite oral vaccination. The humoral immune response was sufficiently low to prevent detection of any significant dose effect of MDP on antibody levels among experimental groups.

CONCLUSIONS

Oral vaccination of young ferrets with Hml and 50 micrograms MDP increased the risk of Helicobacter-associated mucosal ulceration in the proximal duodenum, which was associated with low humoral (but significant cell-mediated) immune responses to H. mustelae. In retrospect, the frequency of vaccination may have suppressed the systemic humoral immune response, thereby promoting mucosal damage by H. mustelae. The 50-microgram dose of MDP enhanced the cell-mediated immune response, which indirectly contributed to development of severe lesions. The increased frequency of mucosal damage associated with this vaccination regimen enhances the value of the ferret model for studying duodenal ulceration secondary to Helicobacter infection.

Helicobacter pylori duodenal colonization in children

To investigate the prevalence and the significance of Helicobacter pylori duodenal colonization, endoscopic duodenal biopsies were performed in 168 children with chronic abdominal pain, gastroesophageal reflux, gastrointestinal bleeding, and malabsorption syndrome. Helicobacter pylori infection was detected in 68 children (40.4%): in 31 of them H. pylori was present in the gastric antrum, and in 37 in the duodenum also. Duodenitis was observed in 25 children with duodenal H. pylori; gastric metaplasia in 3. Scanning electron microscopy revealed the presence of the micro-organism in 3/13 cases; the bacteria were located in the intercellular spaces and alterations of the epithelial surface were found. In conclusion, H. pylori gastritis in children is often associated with duodenal colonization which can cause duodenitis, and also without gastric metaplasia, which indicates a possible role of the micro-organism in the pathogenesis of the lesions.