Pathogenesis and therapy for idiopathic dyspepsia

Randomised clinical trial: rabeprazole improves symptoms in patients with functional dyspepsia in Japan

BACKGROUND

The efficacy of proton pump inhibitors (PPIs) for treating functional dyspepsia (FD) is not well established.

AIM

This study, named the SAMURAI study, aimed to assess the efficacy and dose-response relationship of rabeprazole in Japanese patients with FD in a multicentre, double-blinded, randomised, placebo-controlled trial.

METHODS

Investigated FD was diagnosed using the Rome III criteria. Subjects who did not respond to 1 week of single-blind placebo treatment in a run-in period were randomly assigned to 8 weeks of double-blind treatment with rabeprazole 10 mg, 20 mg, 40 mg or placebo, once daily. Dyspeptic symptoms were assessed by a dyspepsia symptom questionnaire (7-point Likert scale) and symptom diary.

RESULTS

Of 392 subjects entered into the run-in period, 338 were randomly assigned. Although there was no significant difference between placebo and rabeprazole groups in complete symptom relief for four major dyspeptic symptoms, the satisfactory symptom relief of rabeprazole 20 mg was significantly higher than placebo according to the dyspepsia symptom questionnaire (45.3% vs. 28.2%, P = 0.027) and the symptom diary assessment (48.7% vs. 30.0%, P = 0.016). The efficacy was not influenced by syndrome type or Helicobacter pylori status. No statistically significant differences in the incidence of adverse events were seen among treatment groups.

CONCLUSIONS

Rabeprazole 20 mg once daily but not 10 or 40 mg significantly provides satisfactory symptom relief for functional dyspepsia (ClinicalTrials.gov, Number NCT01089543).

Thermal care of functional dyspepsia based on bicarbonate-sulphate-calcium water: a sequential clinical trial

Drug treatment of functional dyspepsia is often unsatisfactory. We assessed the efficacy of a bicarbonate-sulphate-calcium thermal water cycle of 12 days, in patients with functional dyspepsia. Patients with functional dyspepsia were sent by their general practitioners to 12 days of treatment with thermal water, 200–400 ml in the morning, at temperature of 33°C (91.4 F) and were evaluated on a strict intention to treat basis. Four efficacy endpoints were analyzed as follows: (i) reduction of the global symptoms score, (ii) reduction of intensity to a level not interfering with everyday activities, (iii) specific efficacy on ulcer-like or dysmotility-like dyspepsia and (iv) esophageal or abdominal-associated symptoms. Statistical significance was reached for all three primary outcomes after the first 29 consecutive patients. Thermal water reduced the global symptom score, reduced intensity of symptoms to a level not interfering with everyday activity, but was unable to completely suppress all symptoms. A parallel effect emerged for ulcer-like and dyspepsia-like subgroups. The effect on heartburn and abdominal symptoms was not significant, suggesting a specific effect of the water on the gastric and duodenal wall. The Roma II criteria identify a natural kind of dyspepsia that improves with thermal water. Ulcer-like and dysmotility-like are not therapeutically distinguishable subgroups. Patients with dominant esophageal or abdominal symptoms should receive a different therapy. Sequential methods are very effective for the evaluation of traditional care practices and should be considered preliminary and integrative to randomized controlled trials in this context.

The study on the role of inflammatory cells and mediators in post-infectious functional dyspepsia

OBJECTIVE

Functional dyspepsia is a common gastrointestinal disorder. The pathogenesis of functional dyspepsia remains unclear. Functional dyspepsia may begin after a bout of gastroenteritis (post-infectious functional dyspepsia) or de novo (nonspecific functional dyspepsia). The aim of this study was to investigate the prevalence and probable mechanisms of post-infectious functional dyspepsia.

MATERIAL AND METHODS

Functional dyspepsia patients with a history of unsanitary food intake and acute gastroenteritis 6-12 months ago were enrolled. (13)C-UBT confirmed absence of H. pylori infection. Controls consisted of healthy nondyspeptic volunteers and patients with nonspecific functional dyspepsia. Gastric biopsies were used for routine histology, immunohistochemistry, electron microscopy, ELISA, HPLC assays and Western blot examination.

RESULTS

Eighty-five subjects were entered including 35 with post-infectious functional dyspepsia, 30 with nonspecific functional dyspepsia, and 20 healthy controls. The number of mast cells in post-infectious functional dyspepsia and nonspecific functional dyspepsia were significantly greater than that in healthy controls. The number of enterochromaffin cells (ECs) in post-infectious functional dyspepsia was significantly higher than those in nonspecific functional dyspepsia or in healthy controls. The number of mast cells and ECs increased with the density of chronic inflammatory cells. The release of histamine and 5-hydroxytryptamine from gastric mucosa of post-infectious functional dyspepsia patients was significantly greater than those from nonspecific functional dyspepsia or healthy controls. Tryptase protein expression was higher in post-infectious functional dyspepsia and nonspecific functional dyspepsia than in healthy controls. The histological score of chronic gastric inflammation was greater in post-infectious functional dyspepsia versus patients with nonspecific functional dyspepsia or healthy controls. Electron microscopy showed secreting granules in the cytoplasm of both mast cells and ECs. The number of activated mast cells and Ecs at a distance of < 5 microm of nerve fibers were significantly greater in post-infectious functional dyspepsia versus nonspecific functional dyspepsia or controls.

CONCLUSIONS

Dyspepsia may occur after an acute onset of gastroenteritis in a part of patients. Potent chemicals derived from mast cells and ECs, including histamine, tryptase and 5-hydroxytryptamine may be involved in the pathogenesis of post-infectious functional dyspepsia.

Prolonged recording of duodenal acid exposure in patients with functional dyspepsia and controls using a radiotelemetry pH monitoring system

INTRODUCTION

Increased duodenal acid exposure (DAE) is associated with ulcer and dyspeptic symptoms but our understanding is limited by cumbersome recording methods. We have recently shown that prolonged radiotelemetry pH monitoring (RpHM) in the duodenum is feasible. This study compared DAE in controls and patients with functional dyspepsia (FD) using RpHM.

METHODS

FD and controls underwent 48-hour recording of DAE using endoclip-secured RpHM capsules in the distal duodenal bulb. Subjects were nil per os except for meals eaten twice daily. FD completed a 14-item symptom checklist. Sleep periods were determined from diaries. Meal periods were defined as the 3-hour period after meal initiation.

RESULTS

Thirty-four FD and 25 controls were studied. Prolonged recordings were obtained in 32/34 FD and 17/25 controls. Reasons for incomplete recordings were capsule dislodgement (7), procedural complication (1), and suspected gastric prolapse of capsule (2). Within groups, pH values for recording periods did not differ. Between groups, FD had significantly lower mean pH values [median (25th to 75th percentile)] during meals [5.11 (4.44 to 5.59) vs. 5.63 (5.17 to 6.10); P=0.003] and upright periods [4.69 (3.92 to 5.64) vs. 5.35 (4.55 to 6.31); P=0.01] but not during sleep. Duodenal pH values did not correlate with symptoms except for complaints of inability to finish a meal with meal (r=-0.341; P=0.05) and sleep (r=-0.383; P=0.03) pH.

CONCLUSIONS

RpHM allows for prolonged recording of DAE. FD have l greater DAE than controls during daytime and meal periods. DAE and symptoms are poorly associated. The association of DAE with inability to finish a meal is consistent with prior studies demonstrating impaired proximal stomach function after duodenal acidification.

How to manage the difficult-to-treat dyspeptic patient

The main causes of dyspepsia are unexplained gastroduodenal symptoms (i.e. functional dyspepsia), peptic ulcer disease, reflux disease and, rarely, malignancy. A careful clinical evaluation and upper endoscopy will exclude most of the major causes of dyspepsia. The absence of alarm features is reassuring. The yield of other diagnostic tests in this clinical situation is low, and repeat endoscopy is unlikely to be cost-effective. By definition, the difficult-to-treat patient with functional dyspepsia has already had Helicobacter pylori infection excluded or eradicated, has failed to respond to an adequate trial of acid-suppression therapy that used appropriate doses and, therefore, seeks other solutions. It is likely that patients who have failed to respond to previous trials of a PPI will not experience therapeutic gains with high-dose PPI therapy. A major gastroduodenal motor disorder should be suspected if there is severe early satiation (inability to finish a normal-sized meal), postprandial fullness, or persistent nausea and vomiting; here, an assessment of gastric emptying or gastric accommodation can be considered, to tailor therapy. Antidepressants (especially low-dose tricyclic agents) and psychological therapies can be useful. Creation of a logical management plan that includes patient education and support remains key.