The H+/K+-ATPase (proton) pump is expressed in human laryngeal submucosal glands

Effects of acids, pepsin, bile acids, and trypsin on laryngopharyngeal reflux diseases: physiopathology and therapeutic targets

PURPOSE

Laryngopharyngeal reflux disease (LPRD) is a general term for the reflux of gastroduodenal contents into the laryngopharynx, oropharynx and even the nasopharynx, causing a series of symptoms and signs. Currently, little is known regarding the physiopathology of LPRD, and proton pump inhibitors (PPIs) are the drugs of choice for treatment. Although acid reflux plays a critical role in LPRD, PPIs fail to relieve symptoms in up to 40% of patients with LPRD. The influence of other reflux substances on LPRD, including pepsin, bile acid, and trypsin, has received increasing attention. Clarification of the substances involved in LPRD is the basis for LPRD treatment.

METHODS

A review of the effects of acids, pepsin, bile acids, and trypsin on laryngopharyngeal reflux diseases was conducted in PubMed.

RESULTS

Different reflux substances have different effects on LPRD, which will cause various symptoms, inflammatory diseases and neoplastic diseases of the laryngopharynx. For LPRD caused by different reflux substances, 24-h multichannel intraluminal impedance combined with pH-metry (MII-pH), salivary pepsin, bile acid and other tests should be established so that different drugs and treatment courses can be used to provide patients with more personalized treatment plans.

CONCLUSION

This article summarizes the research progress of different reflux substances on the pathogenesis, detection index and treatment of LPRD and lays a theoretical foundation to develop target drugs and clinical diagnosis and treatment.

Role and mechanism of Glut-1 and H+/K+-ATPase expression in pepsin-induced development of vocal cord leukoplakia

PURPOSE

We investigated the role of Glut-1 and H⁺/K⁺-ATPase expression in pepsin-induced development of human vocal cord leukoplakia cells (HVCLCs). Next, we analyzed the relationship between Glut-1 and H⁺/K⁺-ATPase expression with the clinicopathological features of laryngeal carcinoma.

METHODS

Glut-1 and H⁺/K⁺-ATPase expression levels in HVCLCs were determined after treatment with artificial gastric juice containing pepsin and laryngeal carcinoma tissues.

RESULTS

Exposure to pepsin-containing artificial gastric juice significantly enhanced the migration and proliferation of VSCLCs in a time-dependent manner. The apoptotic rate of VSCLCs decreased over time after exposure to pepsin and reached a nadir on day 7 (p < 0.01). With increasing duration of exposure to pepsin, the proportion of VSCLCs in G0/G1 phase decreased and the proportions in the S and G2/M phases significantly increased (p < 0.05). After treatment with pepsin-containing artificial gastric juice, RT-PCR and Western blotting showed that the expression of Glut-1 and H⁺/K⁺-ATPase α, β significantly increased in HVCLCs compared to in the absence of pepsin (p < 0.05). The expression of Glut-1 and H⁺/K⁺-ATPase α, β gradually increased from vocal cord leukoplakia (VLC) to laryngeal carcinoma (p < 0.05). Lentivirus-mediated inhibition of Glut-1 expression in VCL significantly inhibited the cells' migration and proliferation (p < 0.05) but enhanced their apoptosis (p < 0.05). Also, inhibition of Glut-1 expression resulted in an increased proportion of cells in G0/G1 phase and a significantly decreased proportion in G2/M phase (p < 0.05).

CONCLUSIONS

Elevated Glut-1 expression may promote the development of VCL by upregulating laryngeal H⁺/K⁺-ATPase expression to reactivate absorbed pepsin, thus damaging the laryngeal mucosa.

Pump Proton and Laryngeal H+/K+ ATPases

Purpose

The presence of extra-gastric H⁺/K⁺ ATPases may explain the clinically significant effect of proton pump inhibitor (PPI) pharmacotherapy in patients with chronic laryngitis related to laryngopharyngeal reflux disease (LPRD) but without gastroesophageal reflux disease (GERD) symptoms. Given the need for a better understanding of GERD and LPRD, we review the various proton pumps with respect to their classification, function, and distribution. We then consider the potential role of the laryngeal H⁺/K⁺ ATPase pump in LPRD.

Methods

We searched databases of PubMed, EMBASE, and Web of Science to achieve related published before September 15, 2020.

Results

There were only seven English-literatures meeting inclusive criteria about laryngeal H⁺/K⁺ ATPases. Some studies provide convincing evidence of a laryngeal H⁺/K⁺ ATPase in normal laryngeal tissues but also suggest the potential role of the proton pump in the abnormal mucus secretion frequently seen in patients with chronic laryngitis.

Conclusion

A laryngeal H⁺/K⁺ ATPase expresses in normal laryngeal tissues. These findings question the current understanding of GERD and LPRD.

Gastric H+/K+-ATPase Expression in Normal Laryngeal Tissue and Laryngeal Carcinoma

Background

Several studies have suggested that laryngopharyngeal reflux disease (LPRD) or gastroesophageal reflux disease (GERD) is an independent risk factor for laryngeal carcinoma. However, it remains unclear whether either condition affects the level of H⁺/K⁺-ATPase expression in laryngeal carcinoma.

Materials and Methods

Immunohistochemistry, real-time RT-PCR, and Western blotting were used to explore the distributions of proton pump (H⁺/K⁺-ATPase) α- and β-subunits in normal laryngeal tissue and laryngeal carcinoma.

Results

Messenger RNAs encoding both the α- and β-subunits were found in the normal epiglottic, ventricular fold, vocal fold, and arytenoid mucosae, as well as epiglottic cartilage. The distributions and expression levels of H+/K+-ATPase α-subunits in various laryngeal subregions did not significantly differ in IHC, RT-PCR, or Western blotting. However, Western blotting revealed a significant difference between the expression level of the β-subunit protein in the epiglottic cartilage and the levels in other sites. The expression levels of both subunits were significantly higher in carcinomatous than in paracarcinomatous tissue and normal laryngeal tissue. The mean follow-up duration was 66.2 months (range, 17–162 months). In all, 4 patients died during follow-up, 4 were lost to follow-up, and 22 were alive and free of disease at the end of follow-up. Two patients developed lung metastases and six developed disease recurrences (at 2, 8, 14, 16, 36, and 41 months). The 3- and 5-year overall survival (OS) rates were 93.0% and 77.0%, respectively. Univariate analyses showed that the 5-year OSs were significantly associated with the T, N, and clinical stages but not with age, alcohol use, pathological differentiation, or the expression levels of the α- or β-subunits (as revealed by IHC, RT-PCR, or Western blotting). However, in multivariate regression analyses, the 5-year OSs were not significantly associated with any clinicopathological factor or the expression levels of either subunit.

Conclusion

H⁺/K⁺-ATPase is expressed in the normal larynx, including in the epiglottic cartilage and the mucosae of the epiglottis, ventricular fold, and arytenoid vocal fold. The expression levels of the H⁺/K⁺-ATPase α- and β-subunits in laryngeal carcinomas were higher than in normal laryngeal tissues.

H+/K+ATPase Expression in the Larynx of Laryngopharyngeal Reflux and Laryngeal Cancer Patients

OBJECTIVES

The gastric H+/K+ ATPase proton pump has previously been shown to be expressed in the human larynx, however its contribution to laryngopharyngeal reflux (LPR) signs, symptoms and associated diseases such as laryngeal cancer is unknown. Proton pump expression in the larynx of patients with LPR and laryngeal cancer was investigated herein. A human hypopharyngeal cell line expressing the proton pump was generated to investigate its effects.

STUDY DESIGN

In-vitro translational.

METHODS

Laryngeal biopsies were obtained from three LPR and eight LSCC patients. ATP4A, ATP4B and HRPT1 were assayed via qPCR. Human hypopharyngeal FaDu cell lines stably expressing proton pump were created using lentiviral transduction and examined via transmission electron microscopy and qPCR for genes associated with inflammation or laryngeal cancer.

RESULTS

Expression of ATP4A and ATP4B was detected in 3/3 LPR, 4/8 LSCC-tumor and 3/8 LSCC-adjacent specimens. Expression of ATP4A and ATP4B in FaDu elicited mitochondrial damage and expression of IL1B, PTGS2, and TNFA (P < .0001); expression of ATP4B alone did not.

CONCLUSIONS

Gastric proton pump subunits are expressed in the larynx of LPR and LSCC patients. Mitochondrial damage and changes in gene expression observed in cells expressing the full proton pump, absent in those expressing a single subunit, suggest that acid secretion by functional proton pumps expressed in upper airway mucosa may elicit local cell and molecular changes associated with inflammation and cancer.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:130-135, 2021.

A comparative study of risk of pneumonia and mortalities between nasogastric and jejunostomy feeding routes in surgical critically ill patients with perforated peptic ulcer

INTRODUCTION

Enteral nutrition (EN) is important in the management of critically illness. Yet, the best route (e.g. pre-pyloric or post-pyloric) for EN in critically ill patients remains to be investigated, especially in specific surgical patients group. In addition, EN could be associated with a higher risk of aspiration pneumonia. Therefore, we evaluate the effect of various EN routes in surgical critically ill perforated peptic ulcer (PPU) patients who underwent surgery and required mechanical ventilation.

METHOD

We collected data of surgical critically ill PPU patients admitted to intensive care unit. The patients were managed with appropriate care bundle and program. To reduce the impact of surgery types, we excluded those who had received other surgical procedures and included patients that only received simple closure. Patients were classified into nasogastric and jejunostomy feeding groups. The demographics, severity scores (e.g.: APACHE II, SOFA, and POSSUM), body mass index (BMI), comorbidities, ventilator days, use of proton pump inhibitors (PPIs), pneumonia occurrence, mortality and complications were collected for analysis.

RESULTS

A total of 136 critically ill PPU patients that received surgery and mechanical ventilation were enrolled. There were 53 patients in NG group and 83 patients in FJ group. There were no differences in demographics, severity scores, BMI, comorbidities, ventilator days, use of PPIs, pneumonia occurrence, mortalities and complications between groups.

CONCLUSION

Our study indicates that there are no differences in mortalities and pneumonia occurrence using nasogastric or feeding jejunostomy in surgical critically ill PPU patients underwent surgery. However, further studies are required.

Association between Proton Pump Inhibitor Use and CNS Infection Risk: A Retrospective Cohort Study

This study investigated the incidence of central nervous system (CNS) infection following the use of proton pump inhibitors (PPIs). A retrospective cohort study was conducted in Taiwan by using data from the National Health Insurance Research Database. We identified and enrolled 16,241 patients with CNS infection who used PPIs (PPI users). The patients were individually propensity score matched (1:1) according to age, sex, hypertension, hyperlipidemia, Charlson comorbidity index (CCI), H2 blocker, non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroid, and immunosuppressant use with 16,241 controls (PPI nonusers). A Cox proportional hazards model was used to estimate adjusted hazard ratio (aHR) for CNS infection in the PPI users and nonusers. After adjustment for other confounding factors, the incidence of CNS infection in the PPI users was 2.23-fold higher than that in the PPI nonusers (95% CI = 1.27⁻3.94). In addition, the PPI users exhibited a higher risk of CNS infection than the nonusers in the hypertension and CCI = 1 groups (aHR = 3.80, 95% CI = 1.40⁻10.32; aHR = 2.47, 95% CI = 1.07⁻5.70 in the PPI users and nonusers, respectively). In conclusions, according to these results, we concluded that the incidence of CNS infection was higher in the PPI users than in the nonusers.

Anti-parietal cell autoimmunity is associated with an accelerated decline of lung function in IPF patients

BACKGROUND

Autoantibodies against lung epithelial antigens are often detected in patients with Idiopathic Pulmonary Fibrosis (IPF). Anti-Parietal Cell Antibodies (APCA) target the H+/K+ATPase (proton pump). APCA prevalence and lung H+/K+ATPase expression was never studied in IPF patients.

METHODS

We retrospectively collected clinical, lung function and imaging data from APCA positive patients (APCA+IPF) and compared them with APCA negative IPF patients matched on the date of diagnostic assessment. H+/K+ATPase expression was assessed with immunohistochemistry and PCR.

RESULTS

Among 138 IPF patients diagnosed between 2007 and 2014 and tested for APCA, 19 (13.7%) APCA+ patients were identified. APCA+IPF patients were 16 men and 3 women, mean age 71 years. The median titer of APCA was 1:160. A pernicious anemia was present in 5 patients and preceded the fibrosis in 3 cases. With a mean follow up of 31 months, 2 patients had an exacerbation and 7 patients died. As compared with 19 APCA- IPF patients, APCA+IPF patients had a less severe disease with better DLCO (57% vs 43% predicted), preserved PaO₂ (85 ± 8 mmHg vs 74 ± 11 mmHg), a lower rate of honeycombing on HRCT (58% vs 89%), but they experienced an accelerated decline of FVC (difference 61.4 ml/year; p = .0002). The H+/K+ATPase was strongly expressed by hyperplastic alveolar epithelial cells in the fibrotic lung.

CONCLUSION

Anti-parietal cell autoimmunity is detected in some IPF patients and is associated with an accelerated decline of lung function. Anti-parietal cell autoimmunity may promote lung fibrosis progression.

Oropharyngeal Reflux Monitoring and Atypical Gastroesophageal Reflux Disease

The prevalence of gastroesophageal reflux disease (GERD) has been increasing since the 1990 s, with up to 27.8 % of people in North America affected by this disorder. The healthcare burden of patients who primarily have extra-esophageal manifestations of GERD (atypical GERD) is estimated to be 5 times that of patients with primarily heartburn and regurgitation due to lack of a gold standard diagnostic test, poor responsiveness to PPI therapy, and delay in recognition. Empiric twice daily PPI therapy for 1-2 months is currently considered the best diagnostic test, but due to poor responsiveness to PPIs in patients with atypical GERD in multiple randomized controlled trials, newer modes of diagnostic procedures such as oropharyngeal pH monitoring have gained significantly more traction. The utility of oropharyngeal pH monitoring systems such as Restech Dx-pH is currently limited due to lack of consensus on normal and abnormal cutoff values. Recent studies suggest its utility as a prognostic tool and its ability to predict responsiveness to medical and surgical therapy. However, routine use of oropharyngeal pH monitoring is still not widespread due to the lack of well-controlled prospective studies.

pH/multichannel impedance monitoring in patients with laryngo-pharyngeal reflux symptoms - Prediction of therapy response in long-term follow-up

BACKGROUND AND STUDY AIM

Optimal therapy concepts in patients with laryngo-pharyngeal reflux (LPR) are still under discussion. Aim of this study was to evaluate long term symptom relief according to results in combined pH/multichannel impedance (MII) monitoring to predict therapy response and symptom relief during long term follow-up.

PATIENTS AND METHODS

In patients with predominant LPR symptoms, pH/MII monitoring and subsequent proton pump inhibitor (PPI) therapy were evaluated retrospectively after a minimum follow-up period of 36months. Patients were asked to complete symptom based questionnaires.

RESULTS

45 patients were evaluated and classified according to results of pH/MII. Twenty one patients showed a pathological finding in pH/MII. These patients reported significantly higher LPR-symptom intensity scores and a significantly higher LPR symptom-induced impairment of everyday life scores compared to patients with normal pH/MII monitoring at baseline and at follow-up. PPI associated symptom relief was significantly higher in patients with pathologic pH/MII monitoring (p=0.003).

CONCLUSION

In conclusion, combined pH/MII monitoring can reliably predict therapy response to PPIs in LPR patients. With negative results, PPI therapy should be avoided. This approach should be assessed in future prospective clinical trials.

Reflux and Voice Disorders: Have We Established Causality?

A trend of attributing abnormal voice changes to reflux has gained momentum among medical professionals over the last few decades. Evidence supporting the connection between reflux and voice and the use of anti-reflux medication in patients with dysphonia is conflicting and deserves careful examination. In the current health care environment, it is important that medical decisions be based on science rather than anecdote and practice patterns. The goal of this review is to investigate the evidence linking reflux and voice changes. Specifically, this association will be examined in the context of the Bradford-Hill criteria to determine what evidence exists for a causal relationship between this exposure (reflux) and outcome (voice change).

Human Lung Mucous Glands Manifest Evidence of the H+/K+-ATPase Proton Pump

Objectives:

The H+/K+-ATPase proton pump has been demonstrated in human laryngeal submucosal glands, and is not solely present in the parietal cells of the stomach. Although proton secretion is present in the lung, a variety of mechanisms have been elucidated. The hypothesis of this study is that the H+/K+-ATPase proton pump is one additional pathway of proton secretion in the human lung.

Methods:

Fourteen surgical lung specimens from 10 subjects were retrospectively obtained after approval from our Human Subjects Committee. Banked human stomach tissue was used for comparative positive and negative controls. Sections were immunostained with 2 monoclonal antibodies selectively reactive with alpha or beta subunits of the H+/K+-ATPase proton pump.

Results:

In the human lung, consistent staining for both subunits was present in the mucous gland cells and ducts in all specimens in which mucous glands were present (6 specimens from 5 subjects). Overall, weak to strong staining was present in focal areas within the multicellular mucous glands. There was only scant focal staining in the respiratory epithelium in 4 specimens. Stomach parietal cells exhibited strongly positive staining for both subunits of the proton pump. There was no staining in stomach cells that were not morphologically consistent with parietal cells.

Conclusions:

The H+/K+-ATPase proton pump is present in mucous cells and ducts in the human lung, with some variable expression noted. Proton pump inhibitor pharmacotherapy may have a site of action in the human lung, explaining some of the controversies otherwise attributable to interrelatedness of aerodigestive tract disease.

Airway reflux

An ever-increasing number of adult and pediatric disorders have been shown to be influenced or caused by airway reflux. This has become a controversial and complicated aspect of medicine that requires a multidisciplinary approach. Evidence indicates that it is not only the acidic components of gastric refluxate that injure extraesophageal tissues but also the nonacidic components, such as pepsin and bile. There is a realization that proton pump inhibitors will not be effective when nonacidic components of refluxate are causing the problem. New in vitro and in vivo models for the study of airway reflux and new therapeutic and surgical approaches are discussed in this review article.

Pharyngeal pH monitoring in gastrectomy patients - what do we really measure?

AIM

Diagnosis of laryngopharyngeal reflux (LPR) has dramatically increased over the last years. For diagnosis of gastroesophageal reflux, a newly designed pharyngeal probe (Dx-pH) was recently introduced. It is also recommended to guide therapy decision in antireflux surgery. However, diagnostic results are questionable. Therefore, we establish a reliable reference group with asymptomatic patients after total gastrectomy and, thus, complete extinction of gastric acid production.

METHODS

Pharyngeal pH monitoring was performed in 10 consecutive patients with history of total gastrectomy. All patients were off proton pump inhibitor (PPI) therapy and followed a non-acid diet during the complete measurement period.

RESULTS

All procedures were performed without any complication. Six of the 10 asymptomatic gastrectomy patients (60%) had pathological results derived from the validated reference values (Ryan score) in pharyngeal pH monitoring.

CONCLUSION

Pathological pH values assessed by the Dx-pH device, usually interpreted as pathological aerosolized acidic gastroesophageal and/or laryngopharyngeal reflux, are obviously dissociated from gastric acid production. Further studies are required to determine diagnostic value of the new system. Therefore, the pharyngeal pH monitoring system seems currently not to be useful to guide any diagnostic or therapeutic decisions, in particular if surgical therapy is considered.

Risk of community-acquired pneumonia with outpatient proton-pump inhibitor therapy: a systematic review and meta-analysis

BACKGROUND

Proton-pump inhibitors (PPIs) are among the most frequently prescribed medications. Community-acquired pneumonia (CAP) is a common cause of morbidity, mortality and healthcare spending. Some studies suggest an increased risk of CAP among PPI users. We conducted a systematic review and meta-analysis to determine the association between outpatient PPI therapy and risk of CAP in adults.

METHODS

We conducted systematic searches of MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, Scopus and Web of Science on February 3, 2014. Case-control studies, case-crossover, cohort studies and randomized controlled trials reporting outpatient PPI exposure and CAP diagnosis for patients ≥18 years old were eligible. Our primary outcome was the association between CAP and PPI therapy. A secondary outcome examined the risk of hospitalization for CAP and subgroup analyses evaluated the association between PPI use and CAP among patients of different age groups, by different PPI doses, and by different durations of PPI therapy.

RESULTS

Systematic review of 33 studies was performed, of which 26 studies were included in the meta-analysis. These 26 studies included 226,769 cases of CAP among 6,351,656 participants. We observed a pooled risk of CAP with ambulatory PPI therapy of 1.49 (95% CI 1.16, 1.92; I2 99.2%). This risk was increased during the first month of therapy (OR 2.10; 95% CI 1.39, 3.16), regardless of PPI dose or patient age. PPI therapy also increased risk for hospitalization for CAP (OR 1.61; 95% CI: 1.12, 2.31).

DISCUSSION

Outpatient PPI use is associated with a 1.5-fold increased risk of CAP, with the highest risk within the first 30 days after initiation of therapy. Providers should be aware of this risk when considering PPI use, especially in cases where alternative regimens may be available or the benefits of PPI use are uncertain.

New aspects in the pathomechanism and diagnosis of the laryngopharyngeal reflux-clinical impact of laryngeal proton pumps and pharyngeal pH metry in extraesophageal gastroesophageal reflux disease

AIM: To determine the laryngeal H+K+-ATPase and pharyngeal pH in patients with laryngopharyngeal reflux (LPR)-symptoms as well as to assess the symptom scores during PPI therapy.

METHODS: Endoscopy was performed to exclude neoplasia and to collect biopsies from the posterior cricoid area (immunohistochemistry and PCR analysis). Immunohistochemical staining was performed with monoclonal mouse antibodies against human H+K+-ATPase. Quantitative real-time RT-PCR for each of the H+K+-ATPase subunits was performed. The pH values were assessed in the aerosolized environment of the oropharynx (DxpH Catheter) and compared to a subsequently applied combined pH/MII measurement.

RESULTS: Twenty patients with LPR symptoms were included. In only one patient, the laryngeal H+K+-ATPase was verified by immunohistochemical staining. In another patient, real-time RT-PCR for each H+K+-ATPase subunit was positive. Fourteen out of twenty patients had pathological results in DxpH, and 6/20 patients had pathological results in pH/MII. Four patients had pathological results in both functional tests. Nine out of twenty patients responded to PPIs.

CONCLUSION: The laryngeal H+K+-ATPase can only be sporadically detected in patients with LPR symptoms and is unlikely to cause the LPR symptoms. Alternative hypotheses for the pathomechanism are needed. The role of pharyngeal pH-metry remains unclear and its use can only be recommended for patients in a research study setting.

Refractory chronic cough, or the need to focus on the relationship between the larynx and the esophagus

In this review we question the current way of handling tackle a problem of chronic cough, especially by the excessive number of patients who can not find complete relief from your cough by anatomical diagnosis of universal use. From the field of Otolaryngology new perspectives arise now considering the larynx as a preferential afferent stimuli cough reflex arc. Also the constitution laryngopharyngeal reflux gas and new approaches to non-acid reflux and the local action of pepsin in laryngeal deserving of a joint review, which can illuminate new ways to handle the problem of chronic refractory cough. We believe that the chronic cough syndrome hpersensitivity as more precise label for chronic cough, should place particular emphasis on laryngeal sensory neuropathy as cough and reflux the influence that may have on their maintenance, and thereby causes definitely wide related to the syndrome if the larynx is incorporated, place greater number of afferent nerves of chronic cough, which are sure to cover much of the case of refractory cough remain without a satisfactory solution. The close collaboration between Otolaryngology, Gastroenterology and Pneumology in a patient with refractory chronic cough seems now an unavoidable necessity.

First agreement analysis and day-to-day comparison of pharyngeal pH monitoring with pH/impedance monitoring in patients with suspected laryngopharyngeal reflux

OBJECTIVE

Diagnosis of laryngopharyngeal reflux (LPR) is still challenging. Recently a diagnostic device for pH values in the aerosolized environment of the pharynx has been introduced (Dx-pH). We evaluated results of Dx-pH with objective criteria of pH/impedance monitoring (MII) and subjective reflux scoring systems and assessed day-to-day variability.

DESIGN

This study makes use of a prospective single-center trial. Thirty patients with suspected LPR were analyzed. Upper endoscopic examination, manometry, phoniatric examination, and reflux scores were assessed. Dx-pH was performed on two consecutive days, first in combination with MII and second as single measurement. Thereafter, proton pump inhibitor (PPI) trial was performed. Patients were interviewed about symptom relief after 3 months.

RESULTS

There were considerable differences between MII and results on Dx-pH: day 1 (agreement 11 out of 30, kappa 0.137) and day 2 (agreement 14 out of 30, kappa 0.036). Statistically significant differences were detected correlating all single reflux episodes (n = 453) of Dx-pH with MII and vice versa. Furthermore acidic reflux episodes did not result in pH drops of the pharynx. There was a fair agreement between Dx-pH measurements on subsequent days. After follow-up, 3 out of 18 patients with pathological Dx-pH results reported positive response to PPIs, in contrast to 5 out of 6 patients with pathological MII.

CONCLUSION

According to our data, acid pharyngeal pH levels detected with Dx-pH are not related to GERD and acid esophageal reflux episodes do not result in pharyngeal pH alterations. Hence, present etiology of LPR needs to be reconsidered since neither mixed nor gas reflux events result in pharyngeal pH alteration. Other acid-producing or retaining factors should be taken into account.

Role for ion transport in porcine vocal fold epithelial defense to acid challenge

OBJECTIVE

The vocal fold epithelium is routinely exposed to gastric contents, including acid and pepsin, during laryngopharyngeal reflux events. The epithelium may possess intrinsic defenses to reflux. The first objective of the current study was to examine whether vocal fold epithelial ion transport is one potential mechanism of defense to gastric contents. The second objective was to determine whether ion transport in response to gastric contents is associated with the secretion of bicarbonate.

STUDY DESIGN

Prospective design in excised porcine larynges.

SETTING

Laboratory.

SUBJECTS AND METHODS

Porcine vocal folds (N = 56) were exposed on the luminal surface to acid, pepsin, or sham challenges. Ion transport at baseline and following challenge exposure was measured using electrophysiological techniques. To examine specific ion transport mechanisms, vocal folds were pretreated with either a sodium channel blocker or bicarbonate channel blocker.

RESULTS

Within 60 seconds of acid but not pepsin exposure, there was a significant increase in ion transport. This rapid increase in ion transport was transient and related to bicarbonate secretion.

CONCLUSION

The current data suggest that porcine vocal folds immediately increase bicarbonate secretion following exposure to acid. Bicarbonate secretion may act to neutralize acid. These findings contribute to the identification of the mechanisms underlying vocal fold defense to reflux and offer implications for the development of treatments for reflux-induced vocal fold injury.

Western Blot Confirmation of the H+/K+-ATPase Proton Pump in the Human Larynx and Submandibular Gland

Objective. The authors have previously demonstrated the H+/K+-ATPase (proton pump) in human larynx and lung glands via immunohistochemistry (IHC). The present hypothesis is that the proton pump is expressed in other seromucinous glands of the digestive tract that can be confirmed by IHC and Western blot analysis.

Study Design. Prospective controlled tissue analysis study.

Setting. Academic medical institution.

Methods. Ten anonymous fresh-frozen donor specimens were obtained, comprising 3 submandibular glands, 4 larynges, and 3 normal stomach specimens for control. Submandibular gland sections were immunostained with 2 monoclonal antibodies selectively reactive with α or β subunits of the H+/K+-ATPase. Western blot analysis was performed on all specimens.

Results. Consistent IHC staining was observed in the submandibular gland specimens for both α and β subunits. Western blot analysis revealed very strong expression for the stomach at 100 kDa, corresponding to the α protein, and weak but notable banding for all larynx and submandibular gland specimens. Similar findings were noted for the 60- to 80-kDa glycosylated β subunit protein, as well as the 52-kDa β subunit precursor for all specimens.

Conclusion. The H+/K+-ATPase (proton) pump is present in the human larynx and submandibular gland although in much lower concentrations than in the stomach. Proton pump involvement in human aerodigestive seromucinous glands may have a role in protecting mucosa from acid environments (local or systemic), explain heightened laryngeal sensitivity in those patients with laryngopharyngeal reflux, and be a site of action for proton pump inhibitor pharmacotherapy.

Proton pump inhibitor-associated pneumonia: Not a breath of fresh air after all?

Over the past two decades, proton pump inhibitors (PPIs) have emerged as highly effective and relatively safe agents for the treatment of a variety of gastrointestinal disorders. Unfortunately, this desirable pharmacological profile has also contributed to superfluous and widespread use in both the inpatient and outpatient settings. While generally well-tolerated, research published over the last decade has associated these agents with increased risks of Clostridium difficile disease, fractures likely due to calcium malabsorption and both community-acquired (CAP) and hospital-acquired pneumonias (HAP). The mechanism behind PPI-associated pneumonia may be multifactorial, but is thought to stem from compromising the stomach’s “acid mantle” against gastric colonization of acid-labile pathogenic bacteria which then may be aspirated. A secondary postulate is that PPIs, through their inhibition of extra-gastric H⁺/K⁺-ATPase enzymes, may reduce the acidity of the upper aerodigestive tract, thus resulting in increased bacterial colonization of the larynx, esophagus and lungs. To date, several retrospective case control studies have been published looking at the association between PPI use and CAP. Some studies found a temporal relationship between PPI exposure and the incidence of pneumonia, but only two could define a dose-response relationship. Furthermore, other studies found an inverse correlation between duration of PPI use and risk of CAP. In terms of HAP, we reviewed two retrospective cohort studies and one prospective study. One retrospective study in a medical ICU found no increased association of HAP in PPI-exposed patients compared to no acid-lowering therapy, while the other in cardiothoracic surgery patients showed a markedly increased risk compared to those receiving H₂RAs. The one prospective study in ICU patients showed an increased risk of HAP with PPIs, but not with H₂RAs. In conclusion, the current literature shows a slight trend toward an association between PPI use and pneumonia and an increased risk with PPIs over H₂RAs, but the findings are not consistent across all studies. Larger controlled trials still need to be done to better identify the risk that PPIs impart towards patients contracting CAP or HAP. Until these are completed, we will have to continue to extrapolate across smaller controlled trials to predict the associated risks in our respective patient populations. In the interim, it appears prudent to limit the use of PPIs to situations where they are clinically indicated and, in such cases, use them at the lowest effective dose. In the case of prescribing for stress ulcer prophylaxis in ICU patients, perhaps H₂RAs should be used as the preferred agents over PPIs.

Reflux and sleeping disorders: a systematic review

INTRODUCTION

Laryngopharyngeal reflux is perhaps the most extensively researched laryngology topic of the last decade. It has been suggested that some supraoesophageal symptoms, most notably asthma and laryngospasm, may be associated with night-time, or supine, reflux. The aim of this review was to assess the levels of evidence regarding a correlation between night-time reflux, snoring and apnoea.

METHODS

A Medline search was performed using the terms 'reflux', 'night-time', 'larynx', 'gastroesophageal', 'laryngopharyngeal', 'sleep', 'apnoea', 'snoring' and 'ear nose throat'. The retrieved literature was reviewed, focusing on randomised and non-randomised, controlled, prospective trials. Papers on both paediatric and adult populations were included. Non-English language papers were excluded.

RESULTS

We found no randomised, controlled trials or meta-analyses addressing the possible correlation between reflux and snoring and/or apnoea.

CONCLUSIONS

The role of night-time reflux in paediatric and adult snoring and apnoea is well described in the literature, but is based on poor levels of evidence from uncontrolled studies and case reports.

Gastroesophageal reflux disease (GERD): is there more to the story?

Gastroesophageal reflux disease (GERD) affects both men and women worldwide, with the most common symptom of GERD being frequent heartburn. If left untreated, more serious diseases including esophagitis and/or esophageal cancer may result. GERD has been commonly held to be the result of gastric acid refluxing into the esophagus. Recent work, however, has shown that there are acid-producing cells in the upper aerodigestive tract. In addition, acid-producing bacteria located within the upper gastrointestinal tract and oral cavity may also be a contributing factor in the onset of GERD. Proton pump inhibitors (PPIs) are commonly prescribed for treating GERD; these drugs are designed to stop the production of gastric acid by shutting down the H(+)/K(+)-ATPase enzyme located in parietal cells. PPI treatment is systemic and therefore significantly different than traditional antacids. Although a popular treatment choice, PPIs exhibit substantial interpatient variability and commonly fail to provide a complete cure to the disease. Recent studies have shown that H(+)/K(+)-ATPases are expressed in tissues outside the stomach, and the effects of PPIs in these nongastric tissues have not been fully explored. Likewise, acid-producing bacteria containing proton pumps are present in both the oral cavity and esophagus, and PPI use may also adversely affect these bacteria. The use of PPI therapy is further complicated by the two philosophical approaches to treating this disease: to treat only symptoms or to treat continuously. The latter approach frequently results in unwanted side effects which may be due to the PPIs acting on nongastric tissues or the microbes which colonize the upper aerodigestive tract.

Silent reflux: ex juvantibus criteria for diagnosis and treatment of laryngeal disorders

CONCLUSIONS

Some primary laryngeal pathologies with specific clinical presentation may be related to silent laryngeal reflux. An ex adjuvantibus proton pump inhibitor (PPI) treatment may be helpful for showing evidence of such a hidden laryngeal disorder.

OBJECTIVE

To assess the validity of PPI as an ex adjuvantibus criterion for diagnosis and treatment of suspected reflux-associated laryngitis.

PATIENTS AND METHODS

Sixty patients with clinical suspicion of laryngo-pharyngeal reflux (LPR) were identified on the grounds of laryngeal symptoms (dysphonia, cough, globus sensation, increased throat clearing, bad taste, and laryngeal spasm), laryngeal features (arytenoid edema/erythema, partial or total vocal fold erythema, and posterior glottic edema) with or without gastro-esophageal reflux disorder (GERD). They were consequently subdivided in three groups: type I, with LPR symptoms and features without GERD; type II with LPR symptoms and features with GERD; and type III with LPR features only. Types I and III were randomly treated with omeprazole (group A) or with immunostimulating vaccine (group B) for 3 months. Pre- and post-treatment laryngeal features and symptoms in all groups were evaluated by laryngo-stroboscopy and analyzed for statistical correlation.

RESULTS

All omeprazole-treated patients showed improvement of laryngeal features and symptoms. With PPI treatment, a more significant improvement was noticed with respect to nonspecific immunostimulant therapy. Also, patients without LPR symptoms showed improvement of laryngeal features.

Empiric treatment of laryngopharyngeal reflux with proton pump inhibitors: a systematic review

OBJECTIVE

The objective of this study was to define the outcome of empiric treatment of suspected laryngopharyngeal reflux (LPR) symptoms with proton pump inhibitors (PPIs).

DESIGN

The authors conducted a systematic review of the English and foreign literature. Studies that used PPIs as an empiric treatment modality for suspected LPR, whether alone or in combination with other acid suppressants and/or placebo, were included. Studies that did not include PPIs as a treatment option were excluded.

MAIN OUTCOME MEASURES

A lack of common outcome measures was evident in the uncontrolled studies. In the randomized, controlled trials, outcome measures included symptom questionnaires and videolaryngoscopy. Only one study used computerized voice analysis.

RESULTS

Fourteen uncontrolled studies together with one unblinded, nonrandomized study with a control group of healthy volunteers and six double-blind, placebo-controlled randomized trials were identified from 1994 to 2004. Selection bias, blinding of the results, and lack of common outcome measures were some of the problems preventing a formal metaanalysis. Although uncontrolled series reported positive results, randomized, controlled trials demonstrated no statistically significant differences for changes in severity or frequency of symptoms associated with suspected reflux between PPIs and placebo.

CONCLUSIONS

Recommendations for empiric treatment of suspected LPR with PPIs, by far the most common ear, nose and throat practice in the United Kingdom, are based on poor levels of evidence from uncontrolled studies. The few randomized, controlled trials have failed to demonstrate superiority of PPIs over placebo for treatment of suspected LPR.

Awareness of general practitioners towards treatment of laryngopharyngeal reflux: a British survey

OBJECTIVE

Patients with acid reflux can occasionally present with atypical symptoms such as globus pharyngeus, constant throat clearing, chronic cough, hoarseness, catarrh, choking episodes or asthma-like symptoms. The aim of this survey was to determine whether general practitioners are aware of the atypical manifestations of reflux and the differences in treatment between laryngopharyngeal reflux and gastroesophageal reflux.

DESIGN

Questionnaire Survey.

SETTING

Primary Care

RESULTS

One hundred and sixty general practitioners who routinely refer patients to our Department of Otolaryngology were selected and a postal survey was conducted. One hundred and fifty of these responded (94% response rate). The commonest symptoms for which proton pump inhibitors are prescribed are heartburn (65%), followed by a combination of heartburn and other symptoms (15%), chronic cough (4%), choking episodes (4%), asthma-like symptoms (3%), hoarseness (2%), globus (2%), catarrh (1%), dysphagia (1.5%), frequent throat clearing (1.5%), halitosis and/or bitter taste (1%).

CONCLUSIONS

Our results suggest that the majority of the general practitioners surveyed are unaware of the entity laryngopharyngeal reflux or reflux symptom index. More awareness is required in the primary care setting for early recognition of patients with suspected laryngopharyngeal reflux.

Proton pump (H+/K+-ATPase) expression in human laryngeal seromucinous glands

OBJECTIVE

Recent pilot research suggested that the H+/K+-ATPase (proton pump), which is the target of pharmacotherapy for laryngopharyngeal reflux disease (LPRD), is associated with human laryngeal submucosal glands. The hypothesis of this study is that proton pump is expressed in the human larynx, and is not solely associated with the parietal cells of the stomach.

METHODS

Fifteen surgical larynx subjects (27 pathologic specimens) containing seromucinous glands from banked tissue were retrospectively obtained after approval from Human Subjects Committee. Banked human stomach tissue was also obtained for comparative positive and negative controls. Sections were immunostained with two monoclonal antibodies selectively reactive with alpha or beta subunits of the H+/K+-ATPase (proton) pump.

RESULTS

In the human larynx, positive staining was seen in 14 of 15 subjects. Twenty-six specimens showed consistent staining in the seromucinous cells and ducts for the alpha subunit, and 23 specimens for the beta subunit. Stomach parietal cells exhibited strongly positive staining for both the alpha and beta subunits of the proton pump. There was no staining in stomach cells that were not morphologically consistent with the parietal cell.

CONCLUSION

The H+/K+-ATPase (proton) pump is present in seromucinous cells and ducts in the human larynx, with some variable expression noted. Proton pump involvement in human laryngeal seromucinous glands may explain heightened laryngeal sensitivity in those patients with chronic laryngitis believed to have LPRD. Also, proton pump inhibitor pharmacotherapy may have a site of action in the human larynx, explaining some of the controversies attributable to LPRD.

EBM RATING

B-3.