Helicobacter pylori: past, present, and future

Helicobacter pylori. One bacterium and a broad spectrum of human disease! An overview

Since the historical rediscovery of gastric spiral Helicobacter pylori in the gastric mucosa of patients with chronic gastritis by Warren and Marshall in 1983, peptic ulcer disease has been largely viewed as being of infectious aetiology. Indeed, there is a strong association between the presence of H. pylori and chronic active gastritis in histology. The bacterium can be isolated in not less than 70% of gastric and in over 90% of duodenal ulcer patients. Eradication of the organism has been associated with histologic improvement of gastritis, lower relapse rate and less risk of bleeding from duodenal ulcer. The bacterium possesses several virulence factors enabling it to survive the strong acid milieu inside the stomach and possibly damaging host tissues. The sequence of events by which the bacterium might cause gastric or duodenal ulcer is still not fully elucidated and Koch's postulates have never been fulfilled. In the majority of individuals, H. pylori infection is largely or entirely asymptomatic and there is no convincing data to suggest an increase in the prevalence of peptic ulcer disease among these subjects. An increasingly growing body of literature suggests an association between colonization by H. pylori in the stomach and a risk for developing gastric mucosa-associated lymphoid tissue (MALT), MALT lymphoma, gastric adenocarcinoma and even pancreatic adenocarcinoma. The bacterium has been implicated also in a number of extra-gastrointestinal disorders such as ischaemic heart disease, ischaemic cerebrovascular disease, atherosclerosis, and skin diseases such as rosacea, but a causal role for the bacterium is missing. Eradication of H. pylori thus seems to be a beneficial impact on human health. Various drug regimens are in use to eradicate H. pylori involving the administration of three or four drugs including bismuth compounds, metronidazole, clarithromycin, tetracyclines, amoxycillin, ranitidine, omeprazole for 1-2 weeks. The financial burden, side effects and emergence of drug resistant strains due to an increase in the use in antibiotics for H. pylori eradication therapy need further reconsideration.

Association of Helicobacter pylori infection with gastric adenocarcinoma

Gastric adenocarcinoma is the most prevalent cancer in South Korea, and Helicobacter pylori (H. pylori) infection is also common. This study was performed to examine the association between H. pylori infection and gastric cancer, taking into account various other factors. To investigate the association between gastric adenocarcinoma and H. pylori infection, determined by urease-positive reaction in the CLO test, a total of 175 paired specimens (175 tumor and 175 tissues adjacent to tumor) of stomach cancer patients and a total of 113 control specimens were obtained. The positive H. pylori infection rates were 78.9% (138/175) among the patients in specimens of tumor or tissues adjacent to the tumor and 41.6% (47/113) among controls in the CLO test. A positive correlation between H. pylori infection and gastric cancer was observed (age-adjusted odds ratio, 7.0; MH chi2=34.5 with P<0.0005). These data suggest that stomach cancer patients in Korea have high infection rates of H. pylori regardless of site specificity, and this infection might be causally associated with stomach cancer.

Histological evaluation of connective tissue components in the healing process of human gastric ulcer

1. The aim of the present study was the evaluation of human gastric ulcer healing and intractability from the viewpoint of connective tissue components. 2. Based on investigations of clinical status, we divided 78 patients with a gastric ulcer into three groups. All patients underwent gastrectomy and group I consisted of 17 patients operated on for bleeding or perforation, group II consisted of 37 patients operated on for an accompanying gastric carcinoma and group III consisted of 24 patients operated on for ulcer intractability. 3. We evaluated, in resected specimens, angiogenesis by Azan-Mallory staining and fibroplasia by applying proliferating cell nuclear antigen (PCNA) immunostaining. The inflammatory grade and fibrosis at the ulcer base were also evaluated by haematoxylin-eosin and Azan-Mallory staining. 4. Microvessel counts in group III were significantly lower than those in group I and II (P < 0.05). The PCNA labelling index of fibroblasts in group III was significantly lower than that in groups I and II (P < 0.05). The inflammatory grade was severe and fibrosis was excessive in group III. 5. From these results, it is suggested that the reduced angiogenesis and decline in fibrous cell proliferation are important factors contributing to gastric ulcer intractability.

Gastric bicarbonate secretion and release of prostaglandin E2 are increased in duodenal ulcer patients but not in Helicobacter pylori-positive healthy subjects

BACKGROUND

Duodenal ulcer (DU) patients have impaired proximal duodenal mucosal bicarbonate secretion at rest and in response to luminal acid with higher acid-stimulated mucosal release of prostaglandin (PG) E2 than healthy subjects. Our purpose was to determine whether this abnormality was present also in the stomach of DU patients.

METHODS

Simultaneous determinations of gastric and duodenal bicarbonate secretion and luminal release of PGE2 were performed in 16 healthy volunteers (5 Helicobacter pylori-positive) and 8 inactive DU patients (all H. pylori-positive).

RESULTS

In healthy volunteers the rates of gastroduodenal bicarbonate secretion and the release of PGE2 were not influenced by H. pylori status. In inactive DU patients the rates of basal (704 +/- 84 versus 356 +/- 40 mumol/h; mean +/- SEM) and vagally stimulated (modified sham feeding) (1724 +/- 376 versus 592 +/- 52 mumol/h) gastric bicarbonate secretion were higher (p < 0.05) than in the health, whereas the corresponding rates (339 +/- 42 versus 591 +/- 51 mumol/h and 543 +/- 99 versus 778 +/- 69 mumol/h) in duodenal bicarbonate secretion were lower (p < 0.05). In addition, inactive DU patients had higher basal (148 +/- 32 versus 53 +/- 5 ng/h) and stimulated (291 +/- 84 versus 131 +/- 25 ng/h) gastric release of PGE2, but only the basal release of PGE2 into the duodenum was significantly increased (20 +/- 3 versus 5 +/- 1 ng/h; p < 0.05).

CONCLUSION

Increased mucosal production of PGE2 may be responsible for the abnormally high gastric secretion of bicarbonate in inactive DU patients. The defective duodenal secretion of bicarbonate observed in these patients may be a consequence of previous ulceration rather than the mere presence of H. pylori infection.

Eradication of Helicobacter pylori with lansoprazole and clarithromycin

BACKGROUND

Helicobacter pylori eradication with omeprazole and clarithromycin varies between 40 and 80%. The dose, frequency and duration of treatment may account for these differences. Lansoprazole, a recently introduced proton pump inhibitor, is a more potent H. pylori bacteriostat in vitro than omeprazole. The aim of this open, comparative, randomized study was to investigate the efficacy and safety of lansoprazole 30 mg once or twice a day (and for 2 vs. 4 weeks) plus clarithromycin 500 mg t.d.s. for 2 weeks. in the eradication of H. pylori.

METHODS

Sixty-six patients with H. pylori infection received clarithromycin 500 mg t.d.s. for 2 weeks and one of four lansoprazole regimens: 30 mg once a day for 2 (Group 1, n = 16) or 4 (Group 2, n = 16) weeks, or 30 mg b.d. for 2 (Group 3, n = 18) or 4 (Group 4, n = 16) weeks. H. pylori eradication was determined by the 13C-urea breath test 4 weeks after finishing treatment.

RESULTS

Per protocol analysis (53 patients) shows that H. pylori was eradicated in 6/13 (46%) in Group 1, 7/13 (54%) in Group 2, 9/14 (64%) in Group 3 and 9/13 (69%) in Group 4. Thirty-one of 68 patients experienced side effects. Analysis on an intention-to-treat basis gave similar results.

CONCLUSION

The dose of lansoprazole appears to be more important than the duration of therapy. Dual therapy with lansoprazole and clarithromycin should be investigated further as a possible treatment regimen for H. pylori infection.

The natural course of peptic ulcer disease and its predictors

BACKGROUND

Little is known about today's natural course of peptic ulcer disease (PUD).

METHODS

A follow-up study based on a structured telephone interview was attempted in 728 patients with an endoscopic diagnosis of peptic ulcer in 1980-84.

RESULTS

Seven patients (1%) died because of PUD during the 8- to 10-year follow-up period. Of the 441 interviewed patients 15.2% had experienced no further clinical manifestations of PUD, 10.9% had had bleeding and 0.7% perforation, and 17.5% had been operated on. The operated patients reported fewer symptoms (p < 0.01) during the last 2 weeks before the interview than those not operated on. On an average the unoperated patients had had symptoms and had used histamine-2-receptor antagonists (H2RA) 12 and 10 weeks per year, respectively. Long-term treatment with H2RA was reported by 18%. More than one-third (36%) of the unoperated patients stated that the symptoms had had a significant negative impact on their lives. Age at onset of disease and index ulcer, family history, use of anti-inflammatory drugs and alcohol, bleeding, and another chronic disease were found to be significant predictors of the course.

CONCLUSION

In more than one-third of the patients with PUD the course is still burdened with many symptoms and complications.