Gastric corpus atrophy following eradication of Helicobacter pylori

Low rate of recurrence of Helicobacter pylori infection in spite of high clarithromycin resistance in Pakistan

BACKGROUND

The aim was to investigate the reinfection rate of H. pylori during a follow-up period of 12 months in adults who had undergone eradication therapy.

METHODS

One hundred-twenty patients; 116 with gastritis, 3 with duodenal ulcer and 1 gastric ulcer, were studied. Their mean age was 41±13 years (range 18-77) and male: female ratio of 2:1. H. pylori were cultured and antibiotic sensitivity was determined by Epsilometer test (E-test) for clarithromycin (CLR) and amoxicillin (AMX). Primers of urease C gene of H. pylori and Sau-3 and Hha I restriction enzymes were used for polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). 14C urea breath test (14C-UBT) was performed 4 weeks after the eradication therapy. The successfully treated patients were observed for 12 months with 14C-UBT to assess H. pylori status. If 14C-UBT was negative, it was repeated after every 12 weeks. If 14C-UBT was positive, endoscopy was repeated with biopsies.

RESULT

The eradication therapy was successful in 102(85%) patients. Out of forty-seven H. pylori isolates cultured, clarithromycin sensitivity was present in 30(64%) and amoxicillin in 45(98%), respectively. Follow-up 14C-urea breath tests of all 102 patients who eradicated H. pylori remained negative up to 9 months. However, in 6 patients, the 14C-UBT confirmed recurrence at 12 months. The recurrence rate was 6%.

CONCLUSION

A low rate of recurrence of H. pylori infection was found in patients with dyspeptic symptoms. H. pylori isolates demonstrated a high invitro clarithromycin resistance.

Systematic review: Helicobacter pylori eradication for the prevention of gastric cancer

BACKGROUND

Helicobacter pylori is recognized as one of the most significant risk factors for gastric cancer, and H. pylori eradication has been proposed as a possible primary chemo-preventive strategy to reduce gastric cancer incidence.

AIM

To evaluate the available evidence on the efficacy of H. pylori eradication in the prevention of gastric cancer.

METHODS

Epidemiological, observational and interventional studies, as well as decisional models, were taken into account in this review.

RESULTS

Large-scale epidemiological studies clearly link H. pylori infection with non-cardia gastric cancer. Current evidence suggests that, in a subpopulation of treated subjects, H. pylori eradication prevents the progression of preneoplastic lesions. Studies that have attempted to evaluate the effect of H. pylori eradication on the incidence of gastric cancer have not provided definitive answers. H. pylori eradication seems to reduce the incidence of gastric cancer in patients without baseline precancerous gastric lesions. Decisional models suggest that H. pylori screening could be cost-effective, but there is not yet sufficient evidence to support the setting up of a general screening programme.

CONCLUSION

Helicobacter pylori eradication is a plausible intervention for gastric cancer prevention; however, it seems to be relevant in only a subset of subjects.

Can gastric cancer be prevented by Helicobacter pylori eradication?

Helicobacter pylori infection always causes chronic gastritis and triggers several gastroduodenal pathologies ranging from peptic ulcer disease to gastric cancer. It is well established that H. pylori eradication decreases the incidence of gastroduodenal ulcer and its recurrence. However, despite being accepted as the critical risk factor for gastric cancer, there is no conclusive evidence that H. pylori eradication decreases the incidence of gastric cancer. Bacterial virulence characteristics, as well as genetic predisposition of the host in conjunction with certain environmental conditions, are the major factors which influence the development of gastric cancer. Preclinical and clinical data suggest that reversibility of precancerous lesions (atrophic gastritis and intestinal metaplasia) is possible in some patients after H. pylori eradication. Since neoplastic lesions do not progress - or even regress in some cases - after H. pylori eradication, eradication therapy should be considered even in patients with precancerous lesions. Nonetheless, progression of atrophic gastritis and intestinal metaplasia into cancer has been also demonstrated in patients after H. pylori eradication, suggesting that there might be a point of no return where genetic changes have already happened and are irreversible despite elimination of the triggering carcinogen (H. pylori). At the present time the clinical decision to treat a patient is based on established risk profiles. A general screen-and-treat policy, although desirable, currently awaits a less complex treatment regimen.

Helicobacter pylori eradication has the potential to prevent gastric cancer: a state-of-the-art critique

Helicobacter pylori infection continues to play a key role in gastric diseases. Colonization of the gastric mucosa with the bacterium invariably results in the development of chronic gastritis and subsets of patients have a progression of the chronic gastritis to either ulcer or cancer. Epidemiological evidence indicates that the proportion of all gastric cancers attributable to H. pylori infection, and hence potentially preventable upon elimination of this risk factor, is somewhere in the range of 60% to 90%. This portends significant benefit in terms of morbidity and mortality, not least in populations with high prevalence of H. pylori infection coupled with high incidence of gastric cancer. The effect of prophylactic H. pylori eradication on gastric cancer incidence in humans remains unknown, however. Results from randomized trials are eagerly awaited, but availability of strong conclusive results may take many years. A growing number of studies show considerable variation in risk for gastric cancer development, depending on H. pylori strain type and the genetic predisposition of the host. There is also a remote possibility that elimination of the infection may have adverse health implications (e.g., antibiotic resistance), and therefore "simple" risk stratification and targeted chemoprevention is required. Based on "in depth" evidence presented at this workshop, the majority of the scientific task force favored a search-and-treat strategy in first-degree relatives of gastric cancer patients and an overwhelming majority felt that a more general screen-and-treat strategy should be focused in the first instance on a population with a high incidence of H. pylori-associated diseases.

Multifocal atrophic gastritis: pathogenesis and therapeutic implications

OBJECTIVE

This study, carried out on 51 patients with multifocal atrophic gastritis (MAG) and 92 age and sex-matched dyspeptic controls, was designed to examine both exocrine (gastric acid) and endocrine (gastrin) gastric secretion before and after therapeutic intervention including Helicobacter pylori eradication and vitamin C treatment.

METHODS

Fasting and gastrin-releasing peptide-induced gastric acid secretion, serum levels of gastrin and proinflammatory (IL-1beta, IL-8, TNF-alpha) as well as gastric mucosal gene expression of ornithine decarboxylase (ODC), cyclooxygenase 2 (COX-2) and growth factors (epidermal growth factor and transforming growth factor alpha) were determined before and after the eradication of Helicobacter pylori and therapy with large doses (1 g/d) of vitamin C for 3 months.

RESULTS

The H. pylori eradication, assessed by C-urea breath test, and vitamin C therapy failed to reverse the histological atrophy of the gastric mucosa but improved significantly the functional status of the atrophied mucosa, especially its exocrine and endocrine secretory activities, attenuated the expression of premalignant markers such as ODC and COX-2, raised the production of growth factors and diminished the release of proinflammatory cytokines.

CONCLUSIONS

These results indicate that MAG may be considered as an environmental disease of the gastric mucosa, whose functional status can be improved by the eradication of H. pylori combined with antioxidant therapy with large doses of vitamin C.

A follow-up study on the effect of Helicobacter pylori eradication on the severity of gastric histology

Helicobacter pylori genetic diversity and geographic distribution affect the severity of gastric histology; while eradication heals gastritis, the improvement of atrophy and intestinal metaplasia (IM) is still controversial. We investigated whether H. pylori infection and genotypes (cagA-vacA) influence the histological changes and whether eradication resolves these changes. Twenty-one patients (11 duodenal ulcer, 2 gastric ulcer, 8 gastritis) received treatment. Biopsies for CLO, PCR, histology, and culture were collected before and at 1 and 12 months after treatment, and serum samples at 0, 1, 2, 6, and 12 months. H. pylori eradication was achieved in 71% of the patients. Histological scores for H. pylori densities were significantly higher in the antrum and incisura angularis. Scores for mononuclear cell and neutrophil infiltration were significantly higher in regions with a high H. pylori density and improved progressively after eradication. Eight patients with atrophy including five with IM showed no significant changes 12 months after eradication. The cagA gene, detected in 13 (62%), the vacA-sla gene, in 20 (95%), and the vacA-m1 gene, in 12 (57%) of 21 patients were significantly associated with duodenal ulcer. A gradual decline in antibody titer reached an average of 67% 12 months after eradication. H. pylori infection and the associated genotypes (cagA of Western type) affect the severity of the gastric histology (mild forms of atrophy and IM) and the disease outcome. Eradication of H. pylori resulted in healing of gastritis, but with no significant improvement in atrophy or IM.

The dynamics of gastritis

The dynamics of gastritis remain a topic of intense investigation. The results of these investigations have increased our knowledge concerning the development of preneoplastic lesions and cancer of the stomach and given us insight with regard to the interactions among bacterial colonization, chronic inflammation, and carcinogenesis in other organs. The past year has presented us with further data showing that the progression of chronic gastritis to gland loss and gastric cancer is related to the severity of inflammation, which is influenced by the characteristics of the bacterial strain, host genetics, and hypochlorhydria. In contrast, Helicobacter pylori eradication leads to a rapid disappearance of neutrophils in the gastric mucosa. Chronic inflammation with mononuclear cells also improves upon eradication, but at a much slower rate, usually not leading to normalization within the first year after therapy. Whether H. pylori eradication can thus prevent new development of atrophy and metaplasia as well, or lead to regression of pre-existing lesions, has been the topic of many studies by now. Unfortunately, most of these studies have suffered from their case design, limited sample size, and short follow-up. Therefore, the conflict in outcome of these case studies comes as no surprise. The few prospective, randomized, controlled studies, however, strongly confirm that H. pylori eradication leads to healing of gastritis, which can at least halt further development of atrophy and metaplasia. Whether these lesions can truly regress remains to be proven.