Long-term effect of Helicobacter pylori eradication on gastric metaplasia in patients with duodenal ulcer

Clinical significance of widespread gastric metaplasia in the duodenal bulb

BACKGROUND

All the risk factors of peptic ulcer disease are not thoroughly understood.

GOALS

To assess duodenal gastric metaplasia (DGM) in relation to Helicobacter pylori status and endoscopy findings with special reference to the effects of highly selective vagotomy.

STUDY

The study population consisted of 1056 adult patients and an additional 154 patients who had had a highly selective vagotomy. Their clinical and endoscopy records as well as the histology of gastric and duodenal biopsies were evaluated retrospectively. H. pylori infection had been determined by serology and culture.

RESULTS

Widespread (more than 20%) DGM was strongly associated with H. pylori positive duodenal ulcer disease (in 59.7% of patients). The prevalence of DGM diminished progressively the more proximally the ulcer was located in the stomach, and was 2.5% in proximal gastric ulcers patients. In vagotomized patients, the prevalence of widespread DGM (8.4% of patients, median 14 years after operation and the majority still H. pylori positive) was close to that of patients with H. pylori gastritis without peptic ulcer disease (4.5%).

CONCLUSIONS

Widespread DGM is an indicator for an increased risk of duodenal ulcer among H. pylori positive patients and it could be used to select patients for eradication therapy.

New approaches to Helicobacter pylori infection in children

Helicobacter pylori infection is usually acquired during childhood, and evidence-based guidelines regarding diagnosis and treatment of infected children have been recently published. Diseases associated with H. pylori infection are gastritis, duodenal ulcers, mucosal-associated lymphoid-type (MALT) lymphoma, and gastric adenocarcinoma. The association of specific symptoms with H. pylori infection in children and adults (ie, recurrent abdominal pain and nonulcer dyspepsia) remains controversial. Additionally, the role of H. pylori in gastroesophageal reflux disease or in extra-gastrointestinal diseases (ie, coronary artery disease) lacks sufficient evidence to demonstrate causality. The diagnosis of H. pylori-associated diseases in children can reliably be made through gastroduodenal endoscopy with biopsies. Clinical trials are underway for the validation of noninvasive diagnostic tests for the H. pylori-infected child, and current guidelines recommend eradication therapy for infected children with duodenal and gastric ulcer, gastric lymphoma, and atrophic gastritis with intestinal metaplasia. The natural history of childhood H. pylori infection is poorly described. Moreover, rational approaches to the prevention and control of childhood H. pylori infection are critically needed, requiring characterization of the determinants for acquisition and persistence and the disease outcomes following eradication.

Helicobacter pylori infection in children

A number of scientific breakthroughs since H pylori first became recognized as a human pathogen have increased our understanding of the pathogenesis of gastroduodenal disease. In particular, advances in molecular bacteriology and the complete sequencing of the H pylori genome in 1999, and soon thereafter the human genome, provide tools allowing better delineation of the pathogenesis of disease. These molecular tools for both bacteria and host should now be applied to multicenter pediatric studies that evaluate disease outcome. More recent developments indicate that a better understanding of the microbial-host interaction is critical to furthering knowledge with respect to H pylori-induced diseases. Studies are needed to evaluate either DNA-based or more traditional protein-based vaccines, to evaluate more specific antimicrobials that confer minimal resistance, and to evaluate probiotics for the management of H pylori infection. Multicenter multinational studies of H pylori infection in the pediatric population, which include specific, randomized controlled eradication trials, are essential to extend current knowledge and develop better predictors of disease outcome.

Is Helicobacter pylori the primary cause of duodenal ulceration?

Helicobacter pylori infection may not be the primary cause of duodenal ulceration in cases not associated with non-steroidal anti-inflammatory drugs, but may be a secondary complication. In developing countries with a uniformly high prevalence of H. pylori infection there are marked regional differences in the prevalence of duodenal ulcer (DU). In some countries, especially those with a low prevalence of H. pylori, 30-40% or more patients with DU may be H. pylori negative. The absence of H. pylori infection in early cases of DU is also reported. In DU patients with antral H. pylori infection, duodenal colonization by H. pylori may often be absent. After complete H. pylori eradication, recurrence of DU within 6 months in some reports is as high as 20%. The evidence suggests that high acidity and reduced duodenal mucosal resistance remain the primary causes of DU and that H. pylori infection, when present, results in chronicity. Reduced mucosal resistance results in duodenal gastric metaplasia which permits colonization of the duodenum with H. pylori from the antrum. Therefore, whatever causes reduced mucosal resistance may be the primary factor and evidence suggests that this cause may be diet related. This would explain the enigma of regional variations in DU prevalence unrelated to H. pylori prevalence.

The effect of Helicobacter pylori eradication on duodenal gastric metaplasia

We investigated the incidence of duodenal gastric metaplasia and its response to Helicobacter pylori eradication in patients with duodenal ulcer or erosive duodenitis. Gastric and duodenal biopsies were taken from patients with endoscopically detected H. pylori positive duodenal ulcer or erosive duodenitis, and the presence and extent of duodenal gastric metaplasia was recorded. Patients were given omeprazole 20 mg twice daily for 2 weeks, and amoxicillin 1 g and clarithromycin 500 mg twice daily for 10 days, and then ranitidine for a further 8 weeks. Biopsies were repeated 6 months after the start of treatment. Duodenal gastric metaplasia was initially present in 22 patients (52%) and was more frequent in ulcer patients than in duodenitis patients, but not significantly so (69% versus 45%). After treatment, H. pylori was eradicated in 68% of duodenal gastric metaplasia patients and the duodenum was normal endoscopically in 85% of these patients. Duodenal gastric metaplasia was improved or eliminated in 12/15 H. pylori eradicators (80%) and in 5/7 H. pylori non-eradicators (71%), a non-significant difference. The improvement in duodenal gastric metaplasia appeared to be independent of H. pylori eradication.