Helicobacter pylori: from bench to bedside

Development of an animal model of Helicobacter pylori (Indian strain) infection

To develop an animal model for Indian strain Helicobacter pylori (H. pylori) infection. This model will allow one to study many facts of H. pylori infection in a more controlled manner. Mongolian gerbils were orogastric inoculated with two different Indian strains of H. pylori at different time points. Animals were sacrificed and looked for the presence of infection up to 52 weeks post-inoculation using a variety of techniques. Simultaneously, serums from these animals were also tested for antibody, and changes in the histopathology of stomach on H&E (hematoxylin and eosin) stains were also noted. Experimental sets of Mongolian gerbils were orally fed two strains of H. pylori obtained from human case by culture of different cagA and vacA strains three times daily on days 0, 2, and 4. H. pylori ATCC26695 strain was used for antisera preparation; three animals from each group were sacrificed at different time periods 2, 4, 8, 12, 26, 38 and 52 weeks after infection along with one control animal. Infections with H. pylori were confirmed in all the animals from 4 weeks onwards up to 52 weeks with histopathological changes in conformity with H. pylori gastritis. Wild Mongolian gerbils can be infected with Indian strains of H. pylori, and the infection persists at least 1 year. However, intensity of gastritis was milder than that seen in human case.

Gastroesophageal reflux disease in children and adolescents: when and how to treat

Gastroesophageal reflux (GER) is a common presenting complaint in children and adults, and is a frequent reason for physician consultation. GER disease (GERD), whilst benign in the majority of cases, is frequently a chronic condition that has been shown to result in significantly reduced quality of life in children and adolescents. Furthermore, there is emerging evidence that the prevalence of GERD is rising and may have links to adult obesity and other morbidities. Consequently, accurate diagnosis, appropriate management strategies, and timely referral to specialist services are important principles in the effective management of GERD. Acid-suppressive drugs are effective therapies but are one of the most costly classes of drugs prescribed. Therefore, not only is an accurate diagnosis important to the patient, but it is also of significant interest from a public health and resource utilization standpoint.

Diagnosis and management of Barrett's esophagus for the endoscopist

In Barrett's esophagus, the stratified squamous epithelium lining the esophagus is replaced by specialized intestinal-type columnar epithelium. The prevalence of Barrett's esophagus has ranged from 0.9% to 4.5%. The rate of progression from Barrett's esophagus to esophageal adenocarcinoma is 0.5% per patient-year. Proton-pump inhibitors are the mainstay of symptom control in Barrett's patients. Nondysplastic Barrett's and Barrett's with low-grade dysplasia (LGD) are typically managed by periodic surveillance. Radiofrequency ablation is being evaluated as a modality for managing nondysplastic Barrett's and Barrett's with LGD. The options for the management of Barrett's patients with high-grade dysplasia (HGD) include endoscopic therapy, surgery, and intensive surveillance until biopsy reveals adenocarcinoma. Endoscopic therapy involves endoscopic mucosal resection (EMR) and ablation. More aggressive techniques such as endoscopic submucosal dissection and larger segment endoscopic mucosal resection are under study. In this review, we discuss the diagnosis and management of Barrett's esophagus. The recommendations from the major gastroenterologic societies and the current and investigational endoscopic modalities for the management of Barrett's esophagus with and without dysplasia are reviewed.

High prevalence of gastroesophageal reflux disease with minimal mucosal change in asthmatic patients

It is known that the prevalence of gastroesophageal reflux disease (GERD) in asthmatic patients is high. Although an endoscopic diagnosis of GERD based on the established Los Angeles (LA) classification requires the detection of erosive mucosal breaks, there are patients with GERD who have prominent erythema of the esophageal membrane without erosive mucosal breaks. Non-erosive mucosal change denotes the minimal change of the discoloring type of reflux esophagitis. This study was undertaken to determine the prevalence of GERD in asthmatic patients using the LA classification with the inclusion of minimal change, compared to the prevalence determined using the established LA classification without minimal change. The presence of GERD in asthmatic patients (n = 78), non-asthmatic disease control patients (n = 56), and healthy subjects (n = 150) was evaluated by endoscopic examination. The frequency of GERD in asthmatic patients based on the LA classification with minimal change was higher (54/78, 69.2%) than in asthmatic patients based on the LA classification without minimal change (37/78, 47.4%) (p < 0.05). The prevalence of GERD in asthmatic patients (69.2%) was higher than that in disease control patients (17/56, 30.4%) and healthy subjects (27/150, 18.0%) based on the LA classification with minimum change. These data indicate that asthmatic patients have a high frequency of GERD. In addition, without the inclusion of minimum change to the diagnosis of GERD, the prevalence of GERD appears to be underestimated in asthmatic patients. Therefore, physicians should carefully observe asthmatic patients with minimal change on endoscopy.

A proton pump inhibitor, lansoprazole, ameliorates asthma symptoms in asthmatic patients with gastroesophageal reflux disease

Aspiration of acid to the airway causes airway inflammation, and acid stress to the airway caused by gastroesophageal reflux disease (GERD) has been known as a potential mechanism of deteriorated asthma symptoms. However, the efficacy of the acid suppressive drugs, H(2)-receptor blockers (H(2) blocker) and proton pump inhibitors, on asthma symptoms and pulmonary functions remains controversial. We therefore designed the randomized prospective study to determine the efficacy of an H(2) blocker (roxatidine, 150 mg/day) and a proton pump inhibitor (lansoprazole, 30 mg/day) on asthma symptoms of 30 asthmatic patients with GERD. These patients were divided in the two groups (15 patients for each group) and treated with either roxatidine or lansoprazole. The diagnosis of GERD was established by the method of Los Angeles classification including mucosal minimum change of Grade M and questionnaire for the diagnosis of reflux disease (QUEST) score. The efficacy of acid suppressive drugs was evaluated by peak expiratory flow (PEF), asthma control questionnaire (ACQ) that evaluates the improvement of asthma symptoms, and forced expiratory volume in 1 second (FEV(1.0)). Lansoprazole, but not roxatidine, significantly improved PEF and ACQ scores (p < 0.05) with the improved QUEST scores. However, these acid suppressive drugs did not change the pulmonary function of FEV(1.0) in asthmatic patients. In conclusion, treatment with a proton pump inhibitor, lansoprazole, appears to be useful in improvement of asthma symptoms in asthmatic patients with GERD.

Esomeprazole 20 mg vs. pantoprazole 20 mg for maintenance therapy of healed erosive oesophagitis: results from the EXPO study

BACKGROUND

Following initial healing of erosive oesophagitis, most patients require maintenance therapy to prevent relapse.

AIM

To compare endoscopic and symptomatic remission rates over 6 months' maintenance therapy with esomeprazole or pantoprazole (both 20 mg once daily) in patients with healed erosive oesophagitis.

METHODS

Patients with symptoms of gastro-oesophageal reflux disease and endoscopically confirmed erosive oesophagitis at baseline were randomized to receive esomeprazole 40 mg or pantoprazole 40 mg for up to 8 weeks. Patients with healed erosive oesophagitis and free of moderate/severe heartburn and acid regurgitation at 4 weeks or, if necessary, 8 weeks entered the 6-month maintenance therapy phase of the study.

RESULTS

A total of 2766 patients (63% men; mean age 50 years) received esomeprazole 20 mg (n = 1377) or pantoprazole 20 mg (n = 1389) and comprised the intention-to-treat population. Following 6 months of treatment, the proportion of patients in endoscopic and symptomatic remission was significantly greater for those receiving esomeprazole 20 mg (87.0%) than pantoprazole 20 mg (74.9%, log-rank test P < 0.0001). Esomeprazole 20 mg produced a higher proportion of patients free of moderate to severe gastro-oesophageal reflux disease symptoms and fewer discontinuations because of symptoms than pantoprazole 20 mg (92.2% vs. 88.5%, P < 0.001).

CONCLUSIONS

Esomeprazole 20 mg is more effective than pantoprazole 20 mg for maintenance therapy following initial healing of erosive oesophagitis and relief of gastro-oesophageal reflux disease symptoms.

Systematic review: the efficacy of intermittent and on-demand therapy with histamine H2-receptor antagonists or proton pump inhibitors for gastro-oesophageal reflux disease patients

AIM

To perform a systematic review on the efficacy of intermittent and on-demand therapy with either histamine H2-receptor antagonists or proton pump inhibitors for patients with erosive oesophagitis or symptomatic heartburn.

METHOD

We conducted randomized-controlled trials of non-continuous therapy in gastro-oesophageal reflux disease patients.

RESULTS

Fourteen studies met inclusion criteria. Because of variation in outcome measures statistical pooling of results was not possible. Results were analysed qualitatively. Four studies evaluated intermittent therapy of treatment 3 days a week with omeprazole 20 mg or daily with ranitidine which were not efficacious compared to a daily proton pump inhibitor. Famotidine 10 and 20 mg, ranitidine 75 mg and cimetidine 200 mg were efficacious in five on-demand studies for relief of symptomatic heartburn episodes. In three of four studies, evaluating only non-erosive (endoscopy-negative) gastro-oesophageal reflux disease patients, esomeprazole 20 and 40 mg and omeprazole 10 and 20 mg a day were efficacious using willingness to continue as an endpoint. Lansoprazole 30 mg and omeprazole 20 mg maintained symptom control in 60-70% of healed oesophagitis patients.

CONCLUSIONS

Intermittent proton pump inhibitor or H2-receptor antagonist therapy is not effective in maintaining control in oesophagitis patients. H2-receptor antagonists are effective for relief of heartburn episodes. On-demand proton pump inhibitor therapy may work in a proportion of non-erosive gastro-oesophageal reflux disease patients.

Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is generally a lifelong illness that affects many people, but its significance is often underestimated. Chronic abnormal gastric reflux results in erosive esophagitis in up to 60% of patients with GERD. Esophageal stricture, Barrett's esophagus, and esophageal adenocarcinoma are the most serious complications of GERD. Although heartburn and acid regurgitation are the most common complaints, extraesophageal symptoms such as noncardiac chest pain, laryngitis, coughing, and wheezing can be manifestations of GERD. Unfortunately, the severity of symptoms is not a reliable indicator of the severity of erosive esophagitis. Endoscopy is the preferred method to diagnose and grade erosive esophagitis, and various classification systems are used to grade disease severity. The Los Angeles Classification is a valid and widely accepted system to evaluate the severity of erosive esophagitis. The immediate goals of treatment are to provide effective symptomatic relief and to achieve healing in patients with esophageal damage. The treatment regimen often begins by prescribing a therapy to reduce gastric acid secretion. A proton pump inhibitor is the preferred agent for many patients. Because GERD is a chronic, relapsing disease, long-term maintenance therapy is usually necessary to relieve symptoms, prevent complications, and improve the quality of life in patients with GERD.

Effects of 6-12 months of esomeprazole treatment on the gastric mucosa

OBJECTIVE

The aim of this study was to determine the effect of 6-12 months of treatment with esomeprazole on the histopathology of the gastric mucosa.

METHODS

Two identically designed, randomized, placebo-controlled trials of esomeprazole 40, 20, or 10 mg daily for up to 6 months, as well as a noncomparative, multicenter trial of esomeprazole 40 mg daily for up to 12 months, were conducted in 1326 patients with healed erosive esophagitis (1294 negative for Helicobacter pylori [H. pylori]). Gastric biopsy samples were obtained before treatment and on completion of (or discontinuation from) the trials. Samples were evaluated for the presence of H. pylori, characteristics of acute gastritis or atrophic gastritis, and enterochromaffin-like cell pathology.

RESULTS

During treatment with esomeprazole, the number of patients with an improvement in gastric histological scores was typically greater than or equal to the number who worsened. Gastric histological scores worsened for each corporal or antral characteristic of gastritis in <6.2% of patients. Histological scores with esomeprazole and placebo were similar throughout the 6-month trials. Only one among 1326 patients treated with esomeprazole (H. pylori negative) had evidence of treatment-emergent atrophic gastritis. On final biopsy, 5-12% of patients had abnormal enterochromaffin-like cell scores (simple, linear, or micronodular hyperplasia). There were no instances of enterochromaffin-like cell dysplasia, carcinoids, or neoplasia.

CONCLUSIONS

Patients with healed erosive esophagitis receiving esomeprazole for up to 12 months had minor fluctuations in gastric histological scores, similar to those experienced in untreated populations. Use of esomeprazole did not raise any safety concerns with respect to the development of atrophic gastritis, or cause clinically significant changes in enterochromaffin-like cells.

Medical or surgical therapy for erosive reflux esophagitis: cost-utility analysis using a Markov model

OBJECTIVE

To compare the cost and utility of healing and maintenance regimens of omeprazole and laparoscopic Nissen fundoplication (LNF) in the framework of the Canadian medical system.

SUMMARY BACKGROUND DATA

Medical therapy with proton pump inhibitors for endoscopically proven reflux esophagitis is a safe and effective treatment option. Of late, the surgical treatment of choice for this disease has become LNF.

METHODS

The authors' base case was a 45-year-old man with erosive reflux esophagitis refractory to H2-blockers. A cost-utility analysis was performed comparing the two strategies. A two-stage Markov model (healing and maintenance phases) was used to estimate costs and utilities with a time horizon of 5 years. Discounted direct costs were estimated from the perspective of a provincial health ministry, and discounted quality-of-life estimates were derived from the medical literature. Sensitivity analyses were performed to test the robustness of the model to the authors' assumptions and to determine thresholds. A Monte Carlo simulation of 10,000 patients was used to estimate variances and 95% interpercentile ranges.

RESULTS

For the 5-year period studied, LNF was less expensive than omeprazole (3519.89 dollars vs. 5464.87 dollars per patient) and became the more cost-effective option at 3.3 years of follow-up. The authors found that 20 mg/day omeprazole would have to cost less than 38.60 dollars per month before medical therapy became cost effective; conversely, the cost of LNF would have to be more than 5,273.70 dollars or the length of stay more than 4.2 days for medical therapy to be cost effective. Estimates of quality-adjusted life-years did not differ significantly between the two treatment options, and the incremental cost for medical therapy was 129,665 dollars per quality-adjusted life-years gained.

CONCLUSIONS

For patients with severe esophagitis, LNF is a cost-effective alternative to long-term maintenance therapy with proton pump inhibitors.

Esomeprazole (40 mg) compared with lansoprazole (30 mg) in the treatment of erosive esophagitis

OBJECTIVES

Esomeprazole, the S isomer of omeprazole, has been shown to have higher healing rates of erosive esophagitis than omeprazole. This study compared esomeprazole with lansoprazole for the healing of erosive esophagitis and resolution of heartburn.

METHODS

This United States multicenter, randomized, double blind, parallel group trial was performed in 5241 adult patients (intent-to-treat population) with endoscopically documented erosive esophagitis, which was graded by severity at baseline (Los Angeles classification). Patients received 40 mg of esomeprazole (n = 2624) or 30 mg of lansoprazole (n = 2617) once daily before breakfast for up to 8 wk. The primary efficacy endpoint was healing of erosive esophagitis at week 8. Secondary assessments included proportion of patients healed at week 4, resolution of investigator-recorded heartburn, time to first and time to sustained resolution of patient diary-recorded heartburn, and proportion of heartburn-free days and nights.

RESULTS

Esomeprazole (40 mg) demonstrated significantly higher healing rates (92.6%, 95% CI = 91.5-93.6%) than lansoprazole (30 mg) (88.8%, 95% CI = 87.5-90.0%) at week 8 (p = 0.0001, life-table estimates, intent-to-treat analysis). A significant difference in healing rates favoring esomeprazole was also observed at week 4. The difference in healing rates between esomeprazole and lansoprazole increased as baseline severity of erosive esophagitis increased. Sustained resolution of heartburn occurred faster and in more patients treated with esomeprazole. Sustained resolution of nocturnal heartburn also occurred faster with esomeprazole. Both treatments were well tolerated.

CONCLUSIONS

Esomeprazole (40 mg) is more effective than lansoprazole (30 mg) in healing erosive esophagitis and resolving heartburn. Healing rates are consistently high with esomeprazole, irrespective of baseline disease severity.

Esomeprazole once daily for 6 months is effective therapy for maintaining healed erosive esophagitis and for controlling gastroesophageal reflux disease symptoms: a randomized, double-blind, placebo-controlled study of efficacy and safety

OBJECTIVE

Esomeprazole, the S-isomer of omeprazole, achieves a significantly greater healing rate and symptom resolution of erosive esophagitis than that achieved by omeprazole. The objective of this study is to assess the efficacy of the new proton pump inhibitor esomeprazole in preventing relapse over a prolonged period in patients with healed erosive esophagitis.

METHODS

A total of 318 gastroesophageal reflux patients whose erosive esophagitis was healed in a comparative study of esomeprazole 40 mg, 20 mg, or omeprazole 20 mg, were randomized to maintenance therapy with once daily esomeprazole 40 mg, 20 mg, or 10 mg, or placebo in a U.S., double-blind multicenter trial.

RESULTS

After 6 months, healing was maintained (cumulative life table rates) in 93.6% (95% CI 87.4-99.7) of patients treated with esomeprazole 40 mg, 93.2% (95% CI 87.4-99.0) treated with esomeprazole 20 mg, and 57.1% (95% CI 45.2-69) treated with esomeprazole 10 mg; p < 0.001 vs placebo (29.1%; 95% CI 17.7-40.3). Of patients relapsing, mean time to first recurrence of esophagitis increased with dose, from 34 days (placebo) to 78 days (10 mg), 115 days (20 mg), and 163 days (40 mg). Patients treated with esomeprazole had less frequent and less severe heartburn than those treated with placebo. At month 6, more than 70% of patients being treated with esomeprazole remained symptom-free.

CONCLUSIONS

Esomeprazole is effective and well tolerated in the maintenance of a healing erosive esophagitis. Esomeprazole 40 mg and 20 mg maintain healing in over 90% of patients while providing effective control of heartburn symptoms.

The long-term reinfection rate and the course of duodenal ulcer disease after eradication of Helicobacter pylori in a developing country

OBJECTIVE

The aim of this study was to evaluate the effect of Helicobacter pylori (H. pylori) eradication on the natural history of duodenal ulcer disease and the reinfection rate after treatment in a developing country.

METHODS

A total of 111 H. pylori-infected patients with duodenal ulcer were treated with either omeprazole or famotidine plus two antibiotics for 2 wk. Those failed to respond to treatment were retreated with bismuth-based triple therapy.

RESULTS

The radication rate was 76% (95% CI: 67-83%). Eventually, H. pylori was eradicated in 96 of the 111 patients (86%), who were followed-up clinically and endoscopically for a mean of 37.2 months. The cumulative reinfection rate after eradication (Kaplan-Meier) was 8%+/-3% in yr 1, 11%+/-4% in yr 2, and 13%+/-4% in yr 3. Nine of the 12 reinfections occurred during yr 1. Recurrence of duodenal ulcer was detected in five patients (5.2%), all of them during yr 1 of follow-up. Histologically, gastritis scores (according to the Sydney system) improved significantly after eradication.

CONCLUSIONS

In a high prevalence setting, H. pylori eradication and early reinfection rates after treatment are similar to rates observed in a low prevalence environment, whereas the late reinfection rate seems to be higher. However, up to 3 yr after treatment, most treated patients are free of H. pylori infection and/or ulcer activity. Even longer follow-up studies are necessary to determine whether specific retreatment policies are necessary to maintain long term eradication in developing countries.

Review article: the pharmacokinetics of rabeprazole in health and disease

Rabeprazole, a newly developed proton pump inhibitor, has been shown to be effective for the treatment of gastric and duodenal ulcers and for gastro-oesophageal reflux disease. It is a rapid and potent inhibitor of gastric H+,K(+)-ATPase, the gastric acid (proton) pump. The maximum plasma concentration (Cmax) and the area under the plasma concentration time curve (AUC) are linearly related to dose, while the time to maximum plasma concentration (tmax) and elimination half-life (t1/2) are dose-independent. Rabeprazole is extensively metabolized in the liver via the cytochrome P450 enzyme system, and its metabolites are excreted primarily in the urine. Rabeprazole does not accumulate with repeated dosing. Its bioavailability is not influenced by the coingestion of either food or antacids. The pharmacokinetic profile of rabeprazole is substantially altered in the elderly and patients with stable compensated chronic cirrhosis; however, these alterations are not associated with clinically significant abnormalities in laboratory parameters or serious adverse events. The influence of severe decompensated liver disease on the pharmacokinetics of rabeprazole has not been assessed. The pharmacokinetic profile of rabeprazole is not significantly altered by renal dysfunction requiring maintenance haemodialysis. These findings suggest that dosage adjustment is not required in these special patient populations. Caution should be exercised, however, in patients with severe liver disease.

Rabeprazole: pharmacokinetics in patients with stable, compensated cirrhosis

This single-center, open-label study was undertaken to compare the tolerability and pharmacokinetic profiles of rabeprazole, a new proton-pump inhibitor (PPI), in healthy volunteers and in subjects with chronic cirrhosis. Thirteen healthy men and 10 men with stable, compensated cirrhosis documented by biopsy or liver/spleen scan received a single 20-mg rabeprazole dose. Blood samples were drawn before and up to 24 hours after drug administration for the determination of plasma rabeprazole concentrations using high-performance liquid chromatography. Adverse events, vital signs, electrocardiograms, physical findings, and clinical laboratory test results were monitored before and during treatment to determine how rabeprazole was tolerated. Chronic liver disease substantially altered the pharmacokinetic profile of rabeprazole. The maximum rabeprazole concentration (+/- SD) in subjects with cirrhosis (635+/-199 ng/mL) was approximately 50% higher than that in the healthy volunteers (401+/-246 ng/mL), and both area under the curve and elimination half-life were increased by approximately 100%. Oral clearance in subjects with cirrhosis was 38% of that in the healthy volunteers. Rabeprazole was well tolerated by both groups. Three subjects reported a total of 5 clinical adverse events that were judged as definitely or possibly related to rabeprazole treatment. Some minor changes in laboratory values were judged to be clinically insignificant. In patients with mild-to-moderate liver dysfunction, clearance of this PPI, as with other members of the class, was markedly reduced and plasma levels were increased. Although caution is always warranted in patients with severe liver disease, drug accumulation is unlikely with rabeprazole 20 mg once daily, and dose adjustment does not appear to be indicated in patients with mild-to-moderate liver dysfunction.