Effect of age and correlation between esophageal visceral chemosensitivity and mechanosensitivity in healthy Japanese subjects

A novel prostanoid EP1 receptor antagonist, ONO-8539, reduces acid-induced heartburn symptoms in healthy male volunteers: a randomized clinical trial

BACKGROUND

Patients with proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) have unmet clinical needs. Recently, we reported that esophageal prostaglandin E₂ (PGE₂) plays a crucial role in the generation of heartburn. In the present study, we focused on the PGE₂ receptor, EP1, and investigated the effects of ONO-8539, a novel EP1 receptor antagonist, on heartburn symptoms in healthy male volunteers.

METHODS

This prospective, double-blind, placebo-controlled, two-period crossover study was performed in 20 healthy male subjects. The novel prostanoid EP1 receptor antagonist, ONO-8539 (450 mg), was administered once 4 h prior to acid perfusion test. During the test, hydrochloric acid (0.15 mol l^-1) was perfused into the lower esophagus for 30 min. Acid perception threshold was quantified by the time to first sensation of heartburn and intensity of GI symptoms determined using a validated categorical rating scale, and the area under the curve (AUC) as the total symptom score.

RESULTS

ONO-8539 significantly reduced a total heartburn symptom score, not other upper GI symptom scores, during acid perfusion compared with placebo (AUC for heartburn, 85.0 ± 10.6 for placebo and 56.5 ± 7.2 for ONO-8539; P < 0.01), and significantly extended the time to first sensation of heartburn compared with placebo (5.7 ± 4.3 min for placebo and 9.7 ± 7.2 min for ONO-8539; P < 0.05).

CONCLUSIONS

ONO-8539 attenuated acid-induced heartburn in healthy male subjects, suggesting that EP1 receptors play a role in generation of heartburn symptoms. ONO-8539 is a potential novel therapeutic option for controlling heartburn symptoms in GERD patients. Clinical Trials Registry No: UMIN000015753.

Are the Symptoms of an NSAID-Induced Ulcer Truly Milder Than Those of an Ordinary Ulcer?

Objective

The percentage of patients with nonsteroidal anti-inflammatory drugs (NSAIDs) and low-dose aspirin- (LDA-) induced ulcers who complain of gastrointestinal symptoms has generally been considered to be low. The aim of this study was to examine and compare the symptoms and quality of life (QOL) at peptic ulcer onset.

Methods

This study involved 200 patients who were confirmed by endoscopy to be in the acute stage of gastroduodenal ulcer (A1-H1). Patients completed a self-administered questionnaire (Global Overall Symptom score and SF-8) at ulcer onset, and data were compared between NSAIDs/LDA ulcers and non-NSAIDs/LDA ulcers.

Results

The upper gastrointestinal symptoms score was significantly lower for patients using LDA only (20.5 ± 9.4 in the nonusing group, 19.6 ± 8.6 in the NSAIDs-only group, 16.7 ± 11.6 in the LDA-only group, and 18.5 ± 7.2 in the NSAIDs/LDA group, P < 0.05). The QOL score (physical summary) was significantly lower in the NSAID group (42.1 ± 9.9) than in the nonusing group (47.6 ± 7.6) (P < 0.05). Patients' characteristics showed no significant differences among the groups, with the exception of age.

Conclusion

The severity of upper abdominal symptoms at peptic ulcer onset was similar between NSAID users and nonusers.

Protease-Activated Receptor-2 Up-Regulates Transient Receptor Potential Vanilloid 4 Function in Mouse Esophageal Keratinocyte

BACKGROUND

The reflux of pancreatic-duodenal fluids is implicated in the pathophysiology of proton-pump inhibitor-resistant gastroesophageal reflux disease (GERD). Protease-activated receptor-2 (PAR-2) is activated by proteases, the pancreatic enzyme, trypsin, and the activated PAR-2 enhances transient receptor potential vanilloid 4 (TRPV4) function in neurons. TRPV4 stimulates ATP exocytosis in conjunction with the vesicular nucleotide transporter, which mediates mechano-transduction and vagal stimulation. The aim of the present study was to verify whether the activated PAR-2 up-regulates TRPV4 function in mouse esophageal keratinocytes, which may link to the pathophysiology in PPI-resistant GERD.

METHODS

TRPV4 and PAR-2 expressions were detected by RT-PCR, immunostaining, and western blotting in mouse esophageal keratinocytes. The functional response of TRPV4 to esophageal keratinocytes was analyzed using a Ca(2+) imaging system. Cellular ATP release was examined by luciferase-luciferin reaction. TRPV4 phosphorylation was studied by immunoprecipitation and western blotting.

RESULTS

PAR-2 and TRPV4 mRNAs and proteins were expressed in esophageal keratinocytes. Pre-treatment with trypsin significantly increased the responses to TRPV4 activator in esophageal keratinocytes, probably via the phosphorylation of serine residue of TRPV4 by protein kinase C and resulted in cellular ATP release from the cells.

CONCLUSIONS

Activated PAR-2 with trypsin exposure up-regulated TRPV4 function and increased ATP release in mouse esophageal keratinocytes. This mechanism might be related to the pathophysiology of GERD, especially non-erosive GERD.

The Nonsteroidal Anti-inflammatory Drug Diclofenac Reduces Acid-Induced Heartburn Symptoms in Healthy Volunteers

BACKGROUND & AIMS

We investigated the effects of diclofenac, a nonsteroidal anti-inflammatory drug that inhibits prostaglandin production, on induction of esophageal sensation by acid perfusion in healthy men.

METHODS

We performed a prospective, double-blind, placebo-controlled, 2-period, cross-over study over 3 visits in 12 healthy men. Diclofenac was given 6 hours and 2 hours before an acid perfusion test. During the test, hydrochloric acid (0.15 mol/L) was perfused into the lower esophagus for 30 minutes; we evaluated upper gastrointestinal symptoms using a validated categoric rating scale. Then, we calculated and assessed the acid perfusion sensitivity score (APSS). Biopsy specimens were collected by endoscopy of the distal esophagus before and after acid perfusion; levels of prostaglandin E2 (PGE2) (pg/mg) were measured in the samples using an enzyme-linked immunosorbent assay.

RESULTS

Compared with placebo, diclofenac significantly reduced the APSS for heartburn (82.2 ± 12.2 for placebo and 47.5 ± 8.9 for diclofenac; P < .01). Of the upper gastrointestinal symptoms, only the APSS for heartburn was reduced significantly by diclofenac. Compared with placebo, diclofenac reduced the overproduction of PGE2 by esophageal tissues after acid perfusion (23.3 ± 5.2 for placebo and 11.4 ± 3.5 for diclofenac; P < .05). APSS correlated with the development of heartburn and esophageal levels of PGE2 (r = 0.53; P < .05 for heartburn vs PGE2).

CONCLUSIONS

Diclofenac attenuated acid-induced heartburn by inhibiting PGE2 overproduction in the esophagus. Esophageal PGE2 might be involved in producing heartburn symptoms. Clinical Trials Registry no: UMIN000014595.

Demography and treatment response in patients with predominant non-erosive reflux disease or functional dyspepsia

BACKGROUND AND AIM

Non-erosive reflux disease (NERD) and functional dyspepsia (FD) share some common features, and the appropriateness of managing these diseases independently has been questioned. A post-hoc subgroup analysis of the LEGEND study was performed to compare demographics and treatment response between patients with NERD and patients with FD.

METHODS

Patients with reflux and dyspepsia symptoms who had no endoscopic evidence of mucosal breaks and/or erosions were included and divided into groups with predominant NERD (n = 1546) or FD (n = 614). Patients received lansoprazole for 4 weeks, and their symptoms were evaluated using questionnaires.

RESULTS

FD patients were significantly younger than NERD patients (54 vs 60 years), more likely to have a body mass index < 25 kg/m(2) (72.4% vs 67.1%), less likely to have a hiatal hernia (24.0% vs 31.2%), and more likely to feel continuous stress (54.7% vs 48.0%). After 4 weeks of treatment, > 60% of both patients reported an improvement in reflux symptoms and in most dyspepsia symptoms. The improvement rate for reflux symptoms was lower in FD patients than in NERD patients (P < 0.05), whereas the improvement rate for dyspepsia symptoms did not differ between patient groups.

CONCLUSION

Although no clinically significant differences in pathophysiology exist between NERD and FD, there are some between-group differences in demographic characteristics and improvement rates for reflux symptoms after treatment with lansoprazole. It remains to be discussed whether it is necessary to make a strict differential diagnosis between these two conditions.

Atypical symptoms and health-related quality of life of patients with asymptomatic reflux esophagitis

BACKGROUND AND AIM

Asymptomatic reflux esophagitis (RE) is simply regarded as RE without the typical reflux symptoms, but it is unknown whether patients with asymptomatic RE have atypical symptoms. The aim of this study was to examine the clinical characteristics and health-related quality of life (HRQOL) of patients with asymptomatic RE.

PATIENTS AND METHODS

Consecutive patients with RE were enrolled during January 2010 to August 2012, and of them, 41 who had taken acid-suppressing drugs were excluded, leaving 280 patients as the study group. The patients' symptoms were evaluated using a self-completed questionnaire (modified Frequency Scale for the Symptoms of gastroesophageal reflux disease [FSSG]), as well as an HRQOL questionnaire (SF-8). We defined the typical symptoms of RE as heartburn and regurgitation. Asymptomatic RE was defined if the total symptom score was 0 or the minimum (1 point) for typical reflux symptoms in the modified FSSG.

RESULTS

Of the 280 RE patients, 71.8% (n = 201) were symptomatic and 28.2% (n = 79) were asymptomatic. The atypical symptom scores were significantly lower in asymptomatic RE (2.2 ± 2.2) than in symptomatic RE patients (6.9 ± 5.2) (P < 0.0001), and the HRQOL scores were significantly higher in asymptomatic RE than in symptomatic RE (P < 0.0001). Sleep was significantly less disturbed and chronic cough less frequent in asymptomatic RE than in symptomatic RE.

CONCLUSION

Frequency and severity of atypical symptoms in patients with asymptomatic RE were significantly less than in patients with symptomatic RE, and the HRQOL score was significantly higher in those patients. These observations suggest a specific patient cohort that is truly unlikely to manifest symptoms.