Pharmacological targets in gastro-oesophageal reflux disease

[Treatment of Acid-related Diseases Using Potassium-competitive Acid Blockers]

Proton pump inhibitors (PPIs) have several limitations to their efficacy including insufficient acid suppression, slow onset of action, and variable efficacy among patients due to CYP2C19 metabolism. Potassium-competitive acid blockers inhibit H⁺-K⁺-ATPase in a reversible and K⁺-competitive manner, are novel acid suppressive drugs with rapid onset of action, meal independence, and prolonged control of intragastric acidity compared to PPIs. Potassium-competitive acid blockers exhibited non-inferior therapeutic efficacies on reflux esophagitis, gastric ulcers, and Helicobacter pylori eradication. The review is focused on the unmet needs across the acid-related diseases and recent updates on clinical studies using vonoprazan and tegoprazan.

A preliminary report on the use of Midodrine in treating refractory gastroesophageal disease: Randomized Double-Blind Controlled Trial

Background:

Gastroesophageal reflux disease (GERD) is a common disease with various clinical presentations. Acid suppression with proton pump inhibitors and lifestyle modification may not lead to satisfactory response in a substantial portion of patients. We investigated the possible effect of midodrine in patients with refractory GERD.

Methods:

Patients suffering from GERD and were refractory to one-month course of pantoprazole 40mg twice daily entered the study. This was a pilot, randomized, double-blind, and placebo-controlled study. After randomization, one group received Midodrine 5mg before meals for one month, and the other group received placebo for the same period. Meanwhile, pantoprazole was continued 40mg twice daily in both arms. The severity of symptoms was evaluated by the visual scoring system. Quality of life (QoL) in both groups was measured using a standardized version of Quality of Life in Reflux and Dyspepsia questionnaire (QOLRAD).

Results:

A total of twenty patients were enrolled in this study. There was a significant interaction between the groups and time on all measured scores based on QOLRAD questionnaire. All the markers in the Midodrine group had significant improvement over time, but the placebo group did not show any significant improvement. Both visual severity score and total QoL score in Midodrine arm showed a U shape change during 6 weeks.

Conclusions:

Midodrine before a meal could be useful in alleviating symptoms and improving QoL in the patients with refractory gastroesophageal disease. (www.actabiomedica.it)

Phase III, randomised, double-blind, multicentre study to evaluate the efficacy and safety of vonoprazan compared with lansoprazole in Asian patients with erosive oesophagitis

OBJECTIVE

To establish the non-inferior efficacy of vonoprazan versus lansoprazole in the treatment of Asian patients with erosive oesophagitis (EO).

DESIGN

In this phase III, double-blind, multicentre study, patients with endoscopically confirmed EO were randomised 1:1 to receive vonoprazan 20 mg or lansoprazole 30 mg, once daily for up to 8 weeks. The primary endpoint was EO healing rate at 8 weeks. The secondary endpoints were EO healing rates at 2 and 4 weeks. Safety endpoints included treatment-emergent adverse events (TEAEs).

RESULTS

In the vonoprazan (n=238) and lansoprazole (n=230) arms, 8-week EO healing rates were 92.4% and 91.3%, respectively (difference 1.1% (95% CI -3.822% to 6.087%)). The respective 2-week EO healing rates were 75.0% and 67.8% (difference 7.2% (95% CI -1.054% to 15.371%)), and the respective 4-week EO healing rates were 85.3% and 83.5% (difference 1.8% (95% CI -4.763% to 8.395%)). In patients with baseline Los Angeles classification grade C/D, 2-week, 4-week and 8-week EO healing rates were higher with vonoprazan versus lansoprazole (2 weeks: 62.2% vs 51.5%, difference 10.6% (95% CI -5.708% to 27.002%); 4 weeks: 73.3% vs 67.2%, difference 6.2% (95% CI -8.884 to 21.223); and 8 weeks: 84.0% vs 80.6%, difference 3.4% (95% CI -9.187% to 15.993%)). Overall, EO healing rates appeared higher with vonoprazan versus lansoprazole. TEAE rates were 38.1% and 36.6% in the vonoprazan and lansoprazole group, respectively.

CONCLUSION

Our findings demonstrate the non-inferior efficacy of vonoprazan versus lansoprazole in terms of EO healing rate at 8 weeks in this population. Safety outcomes were similar in the two treatment arms.

TRIAL REGISTRATION NUMBER

NCT02388724.

Adding Acotiamide to Gastric Acid Inhibitors Is Effective for Treating Refractory Symptoms in Patients with Non-erosive Reflux Disease

BACKGROUND

Approximately 30% of patients who are treated with proton pump inhibitors (PPIs) for gastroesophageal reflux disease (GERD) experience persistent symptoms. No prokinetic agent regiments are useful for symptom relief.

AIMS

This study was conducted to examine the effect of adding acotiamide to PPI or vonoprazan refractory GERD.

METHODS

This was a randomized, prospective, double-blind, placebo-controlled trial. Seventy-one patients were enrolled. Patients underwent upper endoscopy before initial therapy [15 reflux esophagitis and 55 non-erosive reflux disease (NERD)]. Patients with persistent reflux symptoms were administered 300 mg/day acotiamide or placebo for 2 weeks. The primary endpoint was overall treatment effect (OTE), and gastrointestinal symptoms were evaluated. High-resolution manometry (HRM) and 24-h multiple intraluminal impedance-pH (MII-pH) monitoring were conducted before and after treatment when possible.

RESULTS

Seventy patients were randomized (35 acotiamide and 35 placebo). Sixteen and 10 patients in the acotiamide and placebo groups, respectively, completed MII-pH and HRM. The OTE improvement rates were 28.6% and 14.3% in patients administered acotiamide and placebo, respectively (p = 0.145). In patients with NERD, however, the OTE improvement rate and responder rate for regurgitation in the acotiamide group was significantly higher than those in the placebo group (29.6 vs. 7.1%; p = 0.030, 37.0 vs. 10.7%; p = 0.021, respectively). Acotiamide significantly reduced the total reflux episodes (p = 0.001), acid (p = 0.020), proximal reflux (p = 0.007), and liquid reflux (p = 0.013) episodes.

CONCLUSION

Adding acotiamide to gastric acid inhibitors can improve symptoms in patients with refractory NERD.

Efficacy of vonoprazan for 24-week maintenance therapy of patients with healed reflux esophagitis refractory to proton pump inhibitors

The aim of the present study was to evaluate the efficacy of a potassium-competitive acid blocker (P-CAB), vonoprazan, for the maintenance therapy of healed reflux esophagitis (RE). A total of 60 patients were enrolled in this open-label, single-center, prospective study. All patients were diagnosed with RE with a frequency scale for the symptoms of gastroesophageal reflux disease (FSSG) total score ≥8 following treatment with standard proton pump inhibitors (PPIs) for a minimum of 8 weeks. Standard PPI treatment was switched to vonoprazan 20 mg once daily for 4 weeks. A total of 52 patients, who had no endoscopic evidence of erosive esophagitis following vonoprazan treatment, received maintenance therapy with vonoprazan 10 mg once daily for 24 weeks. Symptoms were evaluated using the FSSG and Gastrointestinal Symptom Rating Scale (GSRS). Upper gastrointestinal endoscopies were performed following 24 weeks of maintenance therapy. The primary endpoint was to determine the proportion of patients who exhibited maintenance of healed RE refractory to PPIs following 24 weeks of maintenance therapy with vonoprazan 10 mg once daily. Secondary endpoints included evaluation of the proportion of patients with symptomatic non-relapse at 24 weeks. Maintenance therapy with vonoprazan 10 mg once daily prevented relapse of esophageal mucosal breaks in 37/43 (86.0%) patients at 24 weeks. However, the number of patients with symptomatic relapse was 1 (1.9%) and 4 (7.7%) at 4 and 8 weeks, respectively. A total of 4 patients were withdrawn due to loss to follow-up. At the end of the 24-week maintenance period, the symptomatic non-relapse rate for acid reflux-associated and dysmotility symptom FSSG scores were 86.5 and 80.8%, respectively. Furthermore, the symptomatic non-relapse rate for reflux, abdominal pain, indigestion, diarrhea, and constipation GSRS scores at 24 weeks were 86.5, 80.8, 75.0, 71.2 and 76.9%, respectively. No serious adverse events were reported during the study. The mean gastrin level was 1,059 pg/ml. In conclusion, the results of the present study indicate that vonoprazan 10 mg once daily is effective for 24-week maintenance therapy of healed RE refractory to PPIs.

Potassium-competitive acid blockers: Advanced therapeutic option for acid-related diseases

Acid-related diseases (ARDs), such as peptic ulcers and gastroesophageal reflux disease, represent a major health-care concern. Some major milestones in our understanding of gastric acid secretion and ARD treatment reached during the last 50years include 1) discovery of histamine H₂-receptors and development of H₂-receptor antagonists, 2) identification of H⁺,K⁺-ATPase as the parietal cell proton pump and development of proton pump inhibitors (PPIs), and 3) identification of Helicobacter pylori (H. pylori) as the major cause of peptic ulcers and development of effective eradication regimens. Although PPI treatments have been effective and successful, there are limitations to their efficacy and usage, i.e. short half-life, insufficient acid suppression, slow onset of action, and large variation in efficacy among patients due to CYP2C19 metabolism. Potassium-competitive acid blockers (P-CABs) inhibit H⁺,K⁺-ATPase in a reversible and K⁺-competitive manner, and exhibit almost complete inhibition of gastric acid secretion from the first dose. Many pharmaceutical companies have tried to develop P-CABs, but most of their clinical development has been discontinued due to safety concerns or a similar efficacy to PPIs. Revaprazan was developed in Korea and was the first P-CAB approved for sale. Vonoprazan, approved in 2014 in Japan, has a completely different chemical structure and higher pKa value compared to other P-CABs, and exhibits rapid onset of action and prolonged control of intragastric acidity. Vonoprazan is an effective treatment for ARDs that is especially effective in healing reflux esophagitis and for H. pylori eradication. P-CABs, such as vonoprazan, promise to further improve the management of ARDs.

The effects of camicinal, a novel motilin agonist, on gastro-esophageal function in healthy humans-a randomized placebo controlled trial

BACKGROUND

A proportion of patients with foregut dysmotility fail to respond to standard interventions. Motilin agonists may be beneficial in this group. We aimed to determine the effect of camicinal, a novel motilin agonist, on gastrointestinal physiology in healthy volunteers.

METHODS

Healthy male subjects were randomly assigned to receive a single dose of 125 mg camicinal or placebo in a double-blind cross-over design. Esophageal function and reflux indices were assessed using high-resolution manometry (pre and 1.5-h post dose) and 24-h ambulatory multichannel intraluminal impedance/pH. After a standardized meal, subjects ingested a wireless motility capsule from which compartmental transit times and motility indices were derived. Subjects were restudied with the alternate intervention after 7 days.

KEY RESULTS

The study subjects (12 male, mean age 47.4 years, range 22-55) tolerated the drug well, except one who exhibited mild abdominal pain on both placebo and camicinal. In comparison to placebo, gastric emptying time (GET) was accelerated following camicinal (-115.4 min, 95% confidence interval -194.4, -36.4, p = 0.009). No effect was demonstrable on esophageal function, small bowel, colonic, or whole bowel transit times and motility indices. With camicinal, as part of a post hoc analysis, there was a trend association between the percentage reduction in GET and total number of acidic reflux events (r = 0.56, p = 0.09).

CONCLUSIONS & INFERENCES

Camicinal decreases GET and was generally well-tolerated. In health, the direct effects of camicinal are on accelerating GET with a potential secondary benefit of reducing reflux events, which warrant further exploration in patient cohorts.

Randomised clinical trial: the 5-HT4 agonist revexepride in patients with gastro-oesophageal reflux disease who have persistent symptoms despite PPI therapy

BACKGROUND

A substantial proportion of patients with gastro-oesophageal reflux disease (GERD) have only a partial response to proton pump inhibitor (PPI) therapy. Prokinetic drugs may improve reflux symptoms by enhancing oesophageal motility and gastric emptying.

AIM

To evaluate the effect of revexepride, a novel prokinetic 5-hydroxytryptamine type 4 (5-HT4 ) receptor agonist, compared with placebo, in patients with GERD who have a partial response to PPIs.

METHODS

A phase 2b, double-blind, parallel-group study was conducted, in which patients were randomised to one of three revexepride treatment groups (0.1, 0.5 and 2.0 mg three times daily) or placebo (1:1:1:1 ratio). Daily e-diary data captured patients' symptoms over an 8-week treatment period. The primary efficacy outcome was the weekly percentage of regurgitation-free days in the second half of the study (weeks 5-8).

RESULTS

In total, 480 patients were randomised and 477 received treatment (mean age 47.9 years; 61% women). The mean percentage of regurgitation-free days increased from baseline (range, 15.0-18.8%) to week 8 (62.3-70.5%) in all four study arms; however, there were no statistically significant differences in this change between placebo and the three treatment arms. No dose-dependent relationship in treatment effect was observed for any of the study endpoints. The incidence of treatment-emergent adverse events (TEAEs) was revexepride dose-dependent. Only one serious TEAE occurred and none resulted in death.

CONCLUSIONS

Revexepride was no more effective than placebo in controlling regurgitation in patients with GERD symptoms partially responsive to PPIs. Revexepride was well tolerated. ClinicalTrials.gov Identifier: NCT01472939.

Randomized clinical trial: effect of the 5-HT4 receptor agonist revexepride on reflux parameters in patients with persistent reflux symptoms despite PPI treatment

BACKGROUND

Approximately, 20-30% of patients with gastro-esophageal reflux disease (GERD) experience persistent symptoms despite treatment with proton pump inhibitors (PPIs). These patients may have underlying dysmotility; therefore, targeting gastric motor dysfunction in addition to acid inhibition may represent a new therapeutic avenue. The aim of this study was to assess the pharmacodynamic effect of the prokinetic agent revexepride (a 5-HT4 receptor agonist) in patients with GERD who have persistent symptoms despite treatment with a PPI.

METHODS

This was a phase II, exploratory, multicenter, randomized, placebo-controlled, double-blind, parallel-group study in patients with GERD who experienced persistent symptoms while taking a stable dose of PPIs (ClinicalTrials.gov identifier: NCT01370863). Patients were randomized to either revexepride (0.5 mg, three times daily) or matching placebo for 4 weeks. Reflux events and associated characteristics were assessed by pH/impedance monitoring and disease symptoms were assessed using electronic diaries and questionnaires.

KEY RESULTS

In total, 67 patients were enrolled in the study. There were no significant differences between study arms in the number, the mean proximal extent or the bolus clearance times of liquid-containing reflux events. Changes from baseline in the number of heartburn, regurgitation, and other symptom events were minimal for each treatment group and no clear trends were observed.

CONCLUSIONS & INFERENCES

No clear differences were seen in reflux parameters between the placebo and revexepride groups.

The relevance of transient lower oesophageal sphincter relaxations in the pathophysiology and treatment of GORD

Gastro-oesophageal reflux disease (GORD) is associated with the passage of gastric contents into the oesophagus resulting in potential oesophageal damage and impaired quality of life. GORD is a frequently encountered problem in today's population, with 25% of people in western populations reporting such symptoms at least once a month. Proton pump inhibitors (PPI) are the drug of choice, with surgery being employed in refractory cases. Although acid suppression is often effective, some patients remain symptomatic despite maximal PPI therapy. By delving into the mechanisms of the disease, it is clear that transient lower oesophageal sphincter relaxations are a key component of its pathophysiology. Research has demonstrated various therapeutic targets for reducing the frequency of such relaxations through GABA and glutamate modulation, for instance. This review highlights such modulations and hopes to explore these mechanisms and therapeutic targets in an area that will no doubt see a change in its pharmacological management in the near future.

The effect of rabeprazole on LES tone in experimental rat model

INTRODUCTION

Despite adequate treatment with proton pump inhibitors (PPIs), symptoms of gastroesophageal reflux disease (GERD) may remain persistent as well as Barrett's esophagus may emerge. It may be proposed that the relaxant effect of PPIs on the smooth muscles may lead to resistance of symptoms. The aim of this study is to investigate effects of rabeprazole on the lower esophageal sphincter (LES) pressure with a rat model.

MATERIALS AND METHODS

Sixteen rats were grouped as control and treatment groups. After obtaining LES tissues followed by a 60 min equilibration period for stabilization, contractile response to carbachol was obtained by application of single dose of carbachol to have a final concentration of 10(-6) M in the organ bath. After the contractions reached a plateau, concentration-response relationships for rabeprazole were obtained in a cumulative manner in the treatment group.

RESULTS

In the carbachol contracted LES preparations; 1.5 × 10(-6) and 1.5×10(-5) M of rabeprazole caused 6.08% and 11.34% relaxations respectively which were not statistically significant. However, mean integral relaxation value for 4.5 × 10(-5) M of rabeprazole was 17.34% and this relaxation was significant compared with controls.

CONCLUSIONS

In the present study, rabeprazole caused no direct significant change in LES tone in the therapeutic dose range applied to the organ bath. However, rabeprazole at the high dose caused a significant decrease in the LES tone.

Ilaprazole, a new proton pump inhibitor, is primarily metabolized to ilaprazole sulfone by CYP3A4 and 3A5

Ilaprazole is a new proton pump inhibitor, designed for treatment of gastric ulcers, and developed by Il-Yang Pharmaceutical Co (Seoul, Korea). It is extensively metabolised to the major metabolite ilaprazole sulfone. In the present study, several in vitro approaches were used to identify the cytochrome P450 (CYP) enzymes responsible for ilaprazole sulfone formation. Concentrations of ilaprazole sulfone were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Incubation of ilaprazole with cDNA-expressed recombinant CYPs indicated that CYP3A was the major enzyme that catalyses ilaprozole to ilaprazole sulfone. This reaction was inhibited significantly by ketoconazole, a CYP3A inhibitor, and azamulin, a mechanism-based inhibitor of CYP3A, while no substantial effect was observed using selective inhibitors for eight other P450s (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP2E1). In addition, the formation of ilaprazole sulfone correlated well with CYP3A-catalysed testosterone 6β-hydroxylation and midazolam 1'-hydroxylation in 20 different human liver microsome panels. The intrinsic clearance of the formation of ilaprazole sulfone by CYP3A4 was 16-fold higher than that by CYP3A5. Collectively, these results indicate that the formation of the major metabolite of ilaprazole, ilaprazole sulfone, is predominantly catalysed by CYP3A4/5.

The pain system in oesophageal disorders: mechanisms, clinical characteristics, and treatment

Pain is common in gastroenterology. This review aims at giving an overview of pain mechanisms, clinical features, and treatment options in oesophageal disorders. The oesophagus has sensory receptors specific for different stimuli. Painful stimuli are encoded by nociceptors and communicated via afferent nerves to the central nervous system. The pain stimulus is further processed and modulated in specific pain centres in the brain, which may undergo plastic alterations. Hence, tissue inflammation and long-term exposure to pain can cause sensitisation and hypersensitivity. Oesophageal sensitivity can be evaluated ,for example, with the oesophageal multimodal probe. Treatment should target the cause of the patient's symptoms. In gastro-oesophageal reflux diseases, proton pump inhibitors are the primary treatment option, surgery being reserved for patients with severe disease resistant to drug therapy. Functional oesophageal disorders are treated with analgesics, antidepressants, and psychological therapy. Lifestyle changes are another option with less documentation.

Short and long-term PPI treatment for GERD. Do we need more-potent anti-secretory drugs?

Because the reflux of the acidic gastric content into the esophagus plays a major role in the pathogenesis of symptoms of GERD and lesions of erosive esophagitis, acid suppression with a proton pump inhibitor (PPI) is currently the mainstay of anti-reflux therapy. There is a strong correlation between the degree of acid suppression provided by a given drug and its efficacy. The superiority of PPIs over other drugs (antacids, prokinetics and H(2)-receptor antagonists) has now been established beyond doubt, both for short- and long-term treatment. However, there are still some unmet therapeutic needs in GERD; hence, patients with non-erosive reflux disease (NERD) are less responsive to PPIs than those with erosive esophagitis. Moreover, the efficacy of PPIs in patients with atypical symptoms is frequently limited to the relief of associated heartburn or regurgitation. With respect to safety, although most studies on short- and long-term PPI use have provided reassuring data, recent reports have drawn attention to potential side effects or drug-drug interference. Better healing rates in the most severe forms of esophagitis, or a faster onset of symptom relief, may require optimization of acid suppressive therapy with regard to the daily course of acid secretion, especially during the night. Different pharmacological approaches can be considered, with the ultimate goals of achieving faster, stronger and more-sustained acid inhibition. How a better pharmacological profile may translate into clinical benefit should now be tested in appropriate, controlled studies.

Epithelial Na+ channel delta subunit is an acid sensor in the human oesophagus

Gastro-oesophageal reflux disease is caused by the reflux of gastric contents into the oesophagus, and thus the oesophageal lumen is damaged by gastric acid. The acid sensor involved in oesophageal epithelial defense is still unclear. Recently, we described that the epithelial Na(+) channel delta subunit (ENaCdelta) is a candidate molecule for a pH sensor in the human brain. Here, using reverse transcription-polymerase chain reaction and in situ hybridization methods, we showed that the proton-sensitive ENaCdelta was strongly expressed in the epithelial layer of the human oesophagus, representative peripheral tissue that can be exposed to an acidic environment. Other ENaC subunits (alpha, beta, and gamma) were also localized there. Based on the expression pattern, human oesophageal ENaC complex was mimicked in the Xenopus oocyte expression system and the response to acidic pH was recorded using a two-electrode voltage-clamp technique. The human oesophageal-mimicking ENaCdeltabetagammaalpha complex generated an amiloride-sensitive inward current at the holding potential of -60 mV. The ENaCdeltabetagammaalpha current was significantly activated by acidic pH (pH 4.0), approximately equal to the luminal value when gastric acid refluxes into the oesophagus. In conclusion, ENaCdelta is a candidate molecule for pH sensing in the gastrointestinal system in humans, providing a novel therapeutic target for gastro-oesophageal reflux disease.

Advances in roles of prokinetic agents in the treatment of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is characterized by the reflux of gastric content into esophagus with or without histological changes. Pathogenesis of GERD is lower esophageal sphincter (LES) dysfunction, abnormal clearing capacity of refluxed materials, delayed gastric emptying and abnormal resistance of esophageal mucosa to gastric acid, but the primary upper gastrointestinal motility dysfunction is regarded as the most important factor in general. Therefore, prokinetic agents which can restore gastric motility with increasing of LES and esophageal motility have been developed and used frequently in the treatment of GERD. There are several prokinetic agents such as metoclopramide, domperidone, cisapride and mosapride that facilitate acetylcholine release from the enteric cholinergic neurons through a selective 5-HT₄ receptor agonistic action. It is considered that prokinetic agents have the same effect as H2 blocker in the treatment of patients with mild GERD. Additionally, it was reported that a combination therapy with prokinetic agents and proton pump inhibitors (PPI) or H2 receptor antagonists (H2RAs) is more effective than monotherapy in patients with severe GERD. This article reviews the recent advances in the role of prokinetic agents in the treatment of gastroesophageal reflux disease.

Medical therapy of gastroesophageal reflux disease

PURPOSE OF REVIEW

Proton pump inhibitors remain the mainstay of medical therapy in gastroesophageal reflux disease. Despite their increasing use, up to 40% of patients are not fully satisfied with their antireflux therapy. Recent data on efficacy and safety are reviewed and causes of failure are discussed.

RECENT FINDINGS

Several randomized studies and a metaanalysis have shown marginal differences in efficacy between various proton pump inhibitor regimens. In subgroups, however, such as severe esophagitis, esomeprazole may be superior. Poor compliance is one of the main causes of failure. Nonacid reflux is likely to play an important role, especially in patients with regurgitation or cough persisting on therapy. Genetic polymorphisms involved in proton pump inhibitor metabolism, Helicobacter pylori infection or nocturnal acid breakthrough during therapy are probably less important than initially suspected. Recent pharmacological developments include new proton pump inhibitor isomers, potassium competitive acid blockers and inhibitors of transient lower esophageal sphincter relaxations.

SUMMARY

There are still important unmet needs in the treatment of gastroesophageal reflux disease. Optimizing acid control is unlikely to improve the condition of the majority of patients with incomplete proton pump inhibitor response. Inhibition of transient lower esophageal sphincter relaxations remains the major pharmacological target for future drug development.

[Therapeutic innovations in gastroesophageal reflux]

Proton-pump inhibitors remain the most effective treatment for relieving symptoms, healing lesions and preventing recurrences of gastroesophageal reflux (GER). Drugs inhibiting transient relaxation of the lower esophageal sphincter have an unfavorable benefit/risk ratio. Endoscopic methods developed in recent years have not been shown effective in trials versus sham procedures. Surgical treatment is effective in GER but causes frequent uncomfortable side effects that are difficult to treat.

Expression of inducible heme oxygenase-1 in the patiant's mucous membrane of esophagus of reflux esophagitis

AIM: To detect the expression of heme oxygenase-1 (HO-1) in human esophageal mucosa with reflux esophagitis (RE), and to find out the role of gas messenger molecule carbon monoxide (CO) in the pathogenesis of RE.

METHODS: The distributions of HO-1 protein in the esophageal tissues of 77 RE cases and 20 normal controls were detected by immunohistochemistry (SP method).

RESULTS: HO-1 was expressed mainly in the esophageal mucosal epithelium. The expression of HO-1 in RE patients was significantly higher than that in the normal controls (0.2334 ± 0.0511 vs 0.1776 ± 0.0164, P < 0.01).

CONCLUSION: Abnormal expression of HO-1 exists in RE, suggesting that CO may play an important role in the pathogenesis of gastrointestinal motility disorders such as RE.

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