Helicobacter pylori

Future prospects for proton pump inhibitors

Future prospects for proton pump inhibitors depend on their efficacy and safety relative to H2-receptor antagonists, the therapeutic standard for acid peptic disorders. As safety concerns diminish, efficacy considerations become more important as these may pertain to cost effectiveness. Comparative, controlled trials show that omeprazole and lansoprazole are somewhat more effective than H2-blockers in healing duodenal and gastric ulcers, providing faster relief of symptoms. Relapse after cessation of therapy is similar between the two classes. The proton pump inhibitors are substantially more effective in healing lesions and relieving symptoms in patients with reflux oesophagitis, and are particularly effective in cases that have failed to heal after 12 weeks of treatment with H2-blockers. Relapse rates of oesophagitis are significantly less with prolonged treatment with omeprazole than ranitidine. A proton pump inhibitor combined with amoxicillin is less effective than triple therapy with antibiotics and bismuth in eradicating Helicobacter pylori infections, but is more convenient and associated with fewer side-effects. Efficacy might be improved by more optimal dosing regimens. Prospects for reversible proton pump inhibitors depend on the balance between their theoretical advantages and their acid inhibition profile which, at present, closely resembles that of H2-blockers.

Eosinophil infiltration, gastric juice and serum eosinophil cationic protein levels in Helicobacter pylori-associated chronic gastritis and gastric ulcer

INTRODUCTION: Helicobacter pylori is one of the main causes of gastroduodenal diseases, such as chronic gastritis and peptic ulcer. It has been shown that eosinophils increase in the stomach in H. pylori infection. Eosinophilic cationic protein (ECP) is a cytotoxic molecule secreted by the activated eosinophils. However, there are no sufficient data about the role of ECP in H. pylori infection and its effect on ulcer development. In this study we investigated the gastric eosinophilic infiltration, gastric juice and serum ECP levels in patients with chronic gastritis and gastric ulcer associated with H. pylori. MATERIALS AND METHODS: Forty-four H. pylori-positive and 20 H. pylori-negative patients who underwent upper gastrointestinal system endoscopy after admitting with dyspeptic complaints were enrolled in the study. Twenty-one of the H. pylori-positive patients had gastric ulcer while 23 patients had none. During endoscopy, multiple gastric biopsies and juices were taken. In gastric biopsies, H. pylori and eosinophilic infiltration were assessed. Additionally, gastric juice and serum ECP levels were measured. RESULTS: Eosinophil infiltration, gastric juice ECP levels, and gastric juice/serum ECP ratios in the H. pylori-positive group were greater than in the H. pylori-negative group (p < 0.01). There was no statistically significant difference regarding serum ECP levels between the two groups (p > 0.05). When H. pylori-positive patients were compared with regard to gastric ulcer presence, however, there was no significant difference in gastric eosinophil infiltration, gastric juice ECP levels, serum ECP levels, and gastric juice/serum ECP ratios (p > 0.05). CONCLUSION: The results of this study suggest that eosinophils and eosinophil-released ECP may contribute to inflammatory changes seen in chronic gastritis, whereas there is no proof that they play a role in ulcer development.

Oxidized low-density lipoprotein levels circulating in plasma and deposited in the tissues: comparison between Helicobacter pylori-associated gastritis and acute myocardial infarction

BACKGROUND

Oxidized low-density lipoprotein (ox-LDL) is a key factor in the progression of atherosclerosis. We developed a sensitive method for measuring plasma ox-LDL levels using a novel anti-ox-LDL antibody. Recently, several studies have shown positive associations between Helicobacter pylori (H pylori) infection and coronary heart disease. Thus the question arises whether an increase in the plasma levels of ox-LDL occurs in patients with H pylori gastritis.

METHODS

We measured plasma ox-LDL levels in patients with H pylori gastritis (n = 27) and compared them with those in patients with acute myocardial infarction (AMI) (n = 62) and stable angina pectoris (SAP; n = 63) and those in control subjects (n = 64). In addition, ox-LDL localization and the presence of macrophages and neutrophils were studied immunohistochemically in gastritis specimens and in coronary culprit lesions obtained from patients with AMI.

RESULTS

Plasma ox-LDL levels in patients with AMI were significantly higher than those in patients with SAP (P <.0001), patients with H pylori gastritis (P <.0001), or in control subjects (P <.0001; AMI, 1.34 +/- 0.95; SAP, 0.61 +/- 0.29; Gastritis, 0.53 +/- 0.17; control, 0.57 +/- 0.23 ng/5 microg LDL protein). Immunohistochemically, H pylori gastritis specimens showed distinct infiltration of macrophages and myeloperoxidase-positive neutrophils; however, ox-LDL localization was not detected. In contrast, coronary culprit plaques revealed strong positivity for ox-LDL in ruptured lipid cores with abundant macrophage-derived foam cells, and these plaques also contained myeloperoxidase-positive neutrophils.

CONCLUSION

Our results suggest that plasma ox-LDL levels do not seem to be associated with H pylori infection, but do relate to coronary plaque instability in AMI.

Inhibition of Helicobacter pylori adherence by a peptide derived from neuraminyl lactose binding adhesin

Helicobacterpylori, like many other gut colonizing bacteria, binds to sialic acid rich macromolecules present on the gastric epithelium. NLBH (neuraminyl lactose binding haemagglutinin) a 32 kDa adhesin located on the surface of H. pylori has been shown to have specific affinity towards NeuAcalpha2,3Galbeta1,4Gluc(3'SL). This sialic acid moiety is over-expressed in an atrophic stomach undergoing parietal cell depletion. Antibodies against a lysine rich peptide fragment of NLBH inhibit agglutination of human erythrocytes. This lysine rich sequence from NLBH was proposed to be the receptor-binding site. In order to elucidate the binding of NLBH to gastric epithelium, a peptide (D-P-K-R-T-I-Q-K-K-S) was synthesized. A series of experiments were performed involving adherence inhibition assays, 2D-NMR, molecular modelling and measurement of modulation in acid secretion. Results indicated that the peptide fragment could be involved in receptor recognition, which is important for the binding of H. pylori to gastric epithelium. The binding is possibly through hydrogen bonding. Two lysines and a threonine residue seem to be within the hydrogen bonding distance of NeuAcalpha2,3Galbeta1,4Gluc. Further, in vitro assays were performed to evaluate the role of the peptide on acid secretion by parietal cells isolated from human fundal biopsies. Interestingly, the peptide increases acid secretion only in H. pylori negative and in treated patients but not in H. pylori positive patients. This highlights the role of NLBH in acid secretion and could be of some consequence in the prognosis of the disease.

Evaluation of the factors influencing stomach-specific delivery of antibacterial agents for Helicobacter pylori infection

Because Helicobacter pylori infection is localized in the gastric mucus layer and at the mucus layer-epithelial cell interface, we have developed amoxycillin- and metronidazole-containing chitosan microspheres for stomach-specific drug delivery. Drug-loaded porous chitosan microspheres were prepared by simultaneous crosslinking and precipitation with sodium tripolyphosphate. The release of antibacterial agents into simulated gastric fluid (SGF, pH 1.2), and the stability and permeability through gastric mucin, were examined at 37 degrees C. Because of the high porosity of drug-loaded chitosan microspheres, all the amoxycillin and metronidazole were released in 2 h. High-performance liquid chromatography assays of the antibacterial agents in SGF at 37 degrees C indicated 40% degradation of amoxycillin after 10 h. Metronidazole was completely stable for up to 24 h in SGF. Amoxycillin and metronidazole were highly permeable through the gastric mucin gel layer. The results of this study show that acid-stable antibacterial agents, such as metronidazole, that rapidly permeate the gastric mucus layer would be very effective for the complete eradication of H. pylori infection when delivered specifically at the site of infection in the stomach.

Triple therapy for Helicobacter pylori eradication is more effective than long-term maintenance antisecretory treatment in the prevention of recurrence of duodenal ulcer: a prospective long-term follow-up study

BACKGROUND

The effectiveness of Helicobacter pylori eradication treatment and long term acid suppression maintenance in the natural course of duodenal ulcer has not been directly compared.

AIM

To compare in a prospective randomized study the effectiveness of H. pylori eradication on the prevention of recurrence of duodenal ulcer with long-term maintenance acid suppression therapy.

METHODS

One hundred and fourteen duodenal ulcer patients were randomized to the treatment over a 12-month period. Fifty-seven of them received triple therapy consisting of 1 g sucralfate q.d.s. for 28 days, 300 mg metronidazole q.d.s. for 14 days and 250 mg clarithromycin q.d.s. for 14 days. Another 57 received 20 mg omeprazole q.d.s. for 12 months. An upper endoscopy was performed before treatment, at 6 weeks, and 2, 6 and 12 months after the first endoscopy. Side-effects were self-recorded and clinical follow-ups were arranged for up to 4.25 years.

RESULTS

The ulcer healing rate was 90.2% (95% confidence interval (95% CI): 79-97%) in the omeprazole group at 6 weeks as compared to 83.3% (95% CI: 70-93%) in the triple therapy group (P = 0.38). There was a higher success rate of pain control in the omeprazole group. Side-effects were more frequently reported and compliance was poorer in the triple therapy group during the first 4 weeks. During follow-up, more relapses were seen in the omeprazole group (9.8%, 95% CI: 3-21%) than the triple therapy group (4.2%, 95% CI: 1-13%) at 1 year (P = 0.44). All relapses were due to the persistence of H. pylori infection. At the 1 year follow-up, none of the patients who were H. pylori negative had an endoscopic relapse compared to 7 out of 56 patients who remained H. pylori positive (12.5%, 95% CI: 5-24%, P = 0.018). After a mean follow-up of 4.07 years, none of those who remained H. pylori negative had an ulcer relapse while the 11 out of 41 who remained H. pylori positive had an ulcer relapse (26.8%, 95% CI 14-43, P = 0. 0005).

CONCLUSIONS

Both regimens were highly effective in healing ulcers. The eradication of H. pylori infection was associated with more side-effects and poor compliance but was more effective than the maintenance therapy in reducing the recurrence of duodenal ulcers. For the prevention of ulcer recurrence, testing of H. pylori status after triple therapy is more important than maintenance therapy.

Long-term follow-up of duodenal ulcer in children before and after eradication of Helicobacter pylori

BACKGROUND

Helicobacter pylori is a well-known cause of chronic antral gastritis and plays an important role in the pathogenesis of peptic ulcer disease in adults. However, because of the relatively low incidence of duodenal ulcer in childhood, few studies have been directed specifically at the relation between the treatment of H. pylori infection and duodenal ulcer in children. An evaluation in a larger patient population is necessary to draw a conclusion.

METHODS

Twenty-six children with duodenal ulcer and H. pylori antral gastritis received triple therapy (amoxicillin, bismuth, and metronidazole) to investigate whether eradication of the organisms can promote healing and prevent relapse of the ulcers in children. Endoscopic examinations were performed before, 2 months, and 12 months after the beginning of treatment.

RESULTS

H. pylori infection was eradicated in 25 (96%) of the 26 patients who underwent upper endoscopic follow-up. Clinical improvement and ulcer healing were achieved in 24 (92%) of 26 children. During a mean follow-up of nearly 2 years, the annual ulcer relapse rate was estimated to be 9%.

CONCLUSIONS

Triple therapy is the treatment of choice for endoscopically proven duodenal ulcer and histologically proven H. pylori antral gastritis in children. It strongly supports a causal relation between H. pylori and duodenal ulcer disease in children.

Recent advances in gastric emptying scintigraphy

Gastric emptying scintigraphy was introduced more than 25 years ago by Griffith and still remains the gold standard to assess gastric emptying. Test meals, radiopharmaceutical and acquisition procedures have been refined and optimized over the years and the test procedure is now well standardized. However, in its most common use, gastric emptying scintigraphy provides little information on gastric physiology and pathophysiology. Over the last decade, modeling of the liquid- and solid-emptying curves has provided some insight into the complex gastric physiology. Compartmental analysis of the stomach has also provided information on the pathophysiological mechanisms of delayed gastric emptying. Over the past 5 years, the most dramatic development in gastric emptying scintigraphy has been the introduction of digital antral scintigraphy. Digital antral scintigraphy consists primarily of dynamic imaging of the stomach and a refined Fourier transform processing method. This new procedure allows for the visualization of antral contractions and, like manometry, permits quantitative characterization of the frequency and amplitude of these contractions. Overall, this new procedure provides a unique, noninvasive tool to characterize gastric motility, to define the pathophysiological mechanisms of gastric motor disorders, and to evaluate the effect of new gastrokinetic compounds.

Positive correlation between H,K-adenosine triphosphatase autoantibodies and Helicobacter pylori antibodies in patients with pernicious anemia

BACKGROUND

Helicobacter pylori is a major cause of gastritis, and the parietal cell H,K-adenosine triphosphatase (ATPase) is a major autoantigen in autoimmune atrophic corpus gastritis, which may eventually lead to pernicious anemia and/or neuropathy. Whether the bacterium induces the autoimmune response is unknown.

METHODS

By means of enzyme-linked immunosorbent assay the occurrence of antibodies against porcine H,K-ATPase and H. pylori was determined in sera from 30 patients with pernicious anemia.

RESULTS

All sera scored positive against H,K-ATPase, and 25 (83%) scored positive against H. pylori. The titers of antibodies against both antigen preparations inversely correlated with the duration of disease. A possible common epitope in the antigen preparations was tested with a competition assay. There was no indication of a common epitope in either human or porcine H,K-ATPase and H. pylori.

CONCLUSIONS

There was a positive correlation and a high incidence of antibodies against H,K-ATPase and H. pylori in sera from patients with pernicious anemia. These antibodies recognized different epitopes.

Emerging strategies for managing peptic ulcer disease

The relationship between the inhibition of intragastric acidity and healing has been determined for both duodenal and gastric ulcers, with a stronger correlation being evident in duodenal ulcer. Omeprazole is clearly more effective than H2-receptor antagonists in healing duodenal ulcers and in the resolution of attendant symptoms. As the recommended treatment periods are shorter with omeprazole (e.g. 2-4 weeks) than with H2-receptor antagonists (4-8 weeks), omeprazole has also been shown to be more cost-effective. Long-term management strategies for peptic ulcer are evolving rapidly in the light of evidence that Helicobacter pylori eradication reduces or eliminates ulcer relapse. Regimens, such as omeprazole in combination with amoxycillin or clarithromycin, that both eradicate H. pylori and heal ulcers rapidly are appealing because they are simple, well tolerated, convenient and efficient in both healing ulcers and preventing relapse. This comprehensive approach appears to be evolving as the dominant strategy for the future treatment of peptic ulcer diseases. Gastric ulcer disease is also treated more effectively with omeprazole than with H2-receptor antagonists, both in terms of speed and reliability of healing, and in terms of symptom resolution. At 4 weeks, symptom resolution has been specifically examined in six comparative trials; in three of these, omeprazole was superior to the H2-receptor antagonist, and in the other three was at least as good as the H2-receptor antagonist. Omeprazole, 40 mg once daily, effectively heals non-steroidal anti-inflammatory drug (NSAID)-induced ulcers in about 90% of cases, even if NSAID therapy is continued, and is probably the treatment of choice for patients with ulcers requiring continued NSAID therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of discriminant value of dyspepsia subgroups in patients referred for upper endoscopy

BACKGROUND

The subdivision of undiagnosed patients with dyspepsia into symptomatic subgroups (ulcerlike, dysmotilitylike, refluxlike, and nonspecific) may give a clue to the underlying cause; however, the value of this approach in practice is unclear. This study aimed to determine the discriminant value of dyspeptic symptoms and combinations of these symptoms.

METHODS

A consecutive sample of 820 outpatients (median age, 62 years; 47% male) completed, before endoscopy, a validated questionnaire that measured 46 gastrointestinal symptoms.

RESULTS

Of patients with functional dyspepsia (n = 162), 17% had ulcerlike, 9% dysmotilitylike, and 16% refluxlike dyspepsia alone; 31% fell into two or more symptom subgroups; and 27% had nonspecific symptoms. A similar distribution of the dyspepsia subgroups was observed in patients without functional dyspepsia. Younger age, female gender, frequent upper abdominal pain, no (or sometimes) pain relief with antacid use, and infrequent vomiting were predictive of functional dyspepsia vs. all other diagnoses (at a specificity of 80%, the sensitivity was 60%). The dyspepsia subgroups were poor discriminators in a separate model for functional dyspepsia vs. all other diagnoses (at a specificity of 80%, the sensitivity was only 43%).

CONCLUSIONS

The dyspepsia subgroups, as currently defined, appear to have little clinical utility and may be an inappropriate way of classifying dyspepsia.

Immunoelectrophoretic pattern of native mucosal intracellular glycoproteins of hog healthy and drug-intoxicated stomachs and of hog body fluids

Naturally occurring glycoproteins have been extracted from fundic and antral mucosal tissue of the hog stomach by means of nondegrading techniques. Major and retarded glycoprotein fractions separated by gel filtration were further dissociated from appreciable amounts of noncovalently bound proteins by CsCl density gradient centrifugation. Antisera to glycoprotein fractions of fundic and antral regions of the stomach were prepared in rabbits. The major fractions from both gastric regions have similar molecular mass (approximately 2 x 10(6)), sedimentation coefficient (approximately 31.5 s), and specific viscosity (approximately 1.6). Purified fractions from each region were further separated into two subfractions by affinity chromatography on wheat germ lectin. Glycoprotein subfractions from antrum and fundus differ appreciably in their carbohydrate and amino acids content, share antigenic determinants, but do not cross-react with anti-hog serum protein antisera. Further diversity in native mucin glycoproteins was observed by the use of one-(D) and two-dimensional (2D) immunoelectrophoresis; subfractions that cross-react with specific anti-hog gastric glycoproteins were found to contain three or more components. D-Immunoelectrophoretic analyses demonstrated (1) in vivo degradation of glycoprotein components of the major fundic fraction isolated from mucosal tissue of alcohol/acetyl salicylate-intoxicated hog stomachs and (2) in vitro catabolism of major fundic glycoproteins by corresponding mitochondrial lysosomal (ML) acid hydrolases. Furthermore, 2D-immunoelectrophoretic analyses showed that (1) hog synovial fluid and plasma proteins have similar prosthetic moieties as either reacted with anti-hog serum proteins antisera. Nonetheless, locations, shapes, and staining intensities of the immunoprecipitate lines differed, which is indicative of different structures of the carbohydrate moieties of components of synovial fluid and plasma proteins, and (2) only a minor fraction of hog cerebrospinal fluid cross-reacted with anti-hog serum protein antisera. This is contrary to the generally accepted deduction based on high-resolution 2D-electrophoresis, indicative of different compositional patterns of plasma and cerebrospinal fluids.

Maintenance therapy for peptic ulcer--who needs it?

Until recently, peptic ulcer disease implied lifelong susceptibility to symptomatic, asymptomatic or complicated ulcer recurrences. Only about 50% of the ulcers seen endoscopically ever become symptomatic. Asymptomatic ulcers appear clinically unimportant, except in the setting of aspirin (ASA) or NSAID use, where they may lead without warning to fatal complications. Until recently, ulcer disease could not be cured medically: no drug has been shown to prevent ulcer complications occurring in patients taking ASA/NSAIDs. Low-dose maintenance therapy with H2-antagonists reduces recurrences and complications, but is expensive and requires indefinite use. Other anti-ulcer drugs have not been studied enough to conclude with confidence that they are similarly effective. Over 80% of recurrences are infrequent and can be treated when they occur n 20% of ulcer patients have 3 recurrences/yr, ulcer complications, or such poor health that recurrence might prove fatal. Ulcers recurring during maintenance therapy rarely complicate and heal with increasing and maintaining dosage. Eradication of H. Pylori (HP) infection, while difficult, abolishes most recurrences without maintenance therapy. Maintenance therapy is therefore indicated principally when HP can not be eradicated. Surgery is rarely required for uncomplicated disease.

Does the stomach adapt to Helicobacter pylori?

To shed some light on the question of gastric adaptation to Helicobacter pylori infection, an overview is given of the various histopathological and clinical consequences of H. pylori infection in man. H. pylori infection can be considered as a chronic bacterial infection. For many individuals there is a balance between a low degree of infection and a low degree of inflammation. The microbial or host factors in adaptation of this balance are largely unknown. If and how 'downregulation' of the inflammatory/immune response does occur need further study.