Sensitive pepsin immunoassay for detection of laryngopharyngeal reflux

Review article: Diagnosis and management of laryngopharyngeal reflux

BACKGROUND

Laryngopharyngeal reflux has classically referred to gastroesophageal reflux leading to chronic laryngeal symptoms such as throat clearing, dysphonia, cough, globus sensation, sore throat or mucus in the throat. Current lack of clear diagnostic criteria significantly impairs practitioners' ability to identify and manage laryngopharyngeal reflux.

AIMS

To discuss current evidence-based diagnostic and management strategies in patients with laryngopharyngeal reflux.

METHODS

We selected studies primarily based on current guidelines for gastroesophageal reflux disease and laryngopharyngeal reflux, and through PubMed searches.

RESULTS

We assess the current diagnostic modalities that can be used to determine if laryngopharyngeal reflux is the cause of a patient's laryngeal symptoms, as well as review some of the common treatments that have been used for these patients. In addition, we note that the lack of a clear diagnostic gold-standard, as well as specific diagnostic criteria, significantly limit clinicians' ability to determine adequate therapies for these patients. Finally, we identify areas of future research that are needed to better manage these patients.

CONCLUSIONS

Patients with chronic laryngeal symptoms are complex due to the heterogenous nature of symptom pathology, inconsistent definitions and variable response to therapies. Further outcomes data are critically needed to help elucidate ideal diagnostic workup and therapeutic management for these challenging patients.

Portable and Rapid Fluorescence Turn-On Detection of Total Pepsin in Saliva Based on Strong Electrostatic Interactions

Salivary pepsin has been proposed as a promising diagnostic marker for gastroesophageal reflux disease (GERD). However, the activity of human pepsin is strongly influenced by pH, and the acidic condition (pH ∼ 2) is optimal, which is a contradiction for the pepsin detection kit based on its catalytic activity. Thus, its accurate quantification in saliva (neutral pH) by readily rapid tools with simplicity and low cost is still challenging. Herein, a convenient fluorescence assay has been developed for the rapid detection of pepsin at neutral pH based on its electrostatic interaction with SYBR Green (SG) rather than the bioactivity. At neutral pH, the positively charged SG fluorophore can be effectively adsorbed by the negatively charged pepsin due to the low isoelectric point (pI) and large molecular size of pepsin. Thus, the molecular rotation of SG is limited, and its fluorescence intensity is significantly increased. The strategy was further confirmed to have the same fluorescence response as that of normally active and inactivated pepsin. Due to the unique pI of pepsin, the fluorescence strategy is highly selective for pepsin compared to other proteins. On the basis of this strategy, a smartphone-based fluorescence capture device integrated with a programmed Python program was fabricated for both color recognition and the accurate detection of pepsin within 3 min. Under the optimal conditions, this turn-on sensor allowed for the on-site analysis of pepsin with a detection limit of 0.2 μg/mL. Moreover, this strategy was successfully used to assess salivary pepsin to aid in the noninvasive diagnosis of GERD.

Regulatory and pathogenic mechanisms in response to iron deficiency and excess in fungi

Iron is an essential element for all eukaryote organisms because of its redox properties, which are important for many biological processes such as DNA synthesis, mitochondrial respiration, oxygen transport, lipid, and carbon metabolism. For this reason, living organisms have developed different strategies and mechanisms to optimally regulate iron acquisition, transport, storage, and uptake in different environmental responses. Moreover, iron plays an essential role during microbial infections. Saccharomyces cerevisiae has been of key importance for decrypting iron homeostasis and regulation mechanisms in eukaryotes. Specifically, the transcription factors Aft1/Aft2 and Yap5 regulate the expression of genes to control iron metabolism in response to its deficiency or excess, adapting to the cell's iron requirements and its availability in the environment. We also review which iron-related virulence factors have the most common fungal human pathogens (Aspergillus fumigatus, Cryptococcus neoformans, and Candida albicans). These factors are essential for adaptation in different host niches during pathogenesis, including different fungal-specific iron-uptake mechanisms. While being necessary for virulence, they provide hope for developing novel antifungal treatments, which are currently scarce and usually toxic for patients. In this review, we provide a compilation of the current knowledge about the metabolic response to iron deficiency and excess in fungi.

3-Hydroxyflavone - bovine serum albumin complex used as fluorescent probe for the detection of pepsin

In this study, a method for the determination of pepsin using a 3-hydroxyflavone (3-HF)-bovine serum albumin (BSA) complex as a fluorescent probe was established. Under acidic conditions, 3-HF can react with BSA to emit strong green fluorescence, which involves an excited state intramolecular proton transfer and fluorescence resonance energy transfer. After pepsin is added, the fluorescence of the 3-HF-BSA system is quenched due to the hydrolysis of BSA. The degree of 3-HF-BSA fluorescence quenching has a good linear relationship with the concentration of pepsin in the range of 10-80 μg/mL. The correlation coefficient was R² = 0.9932 and the detection limit was 2.41 μg/mL. This method has high selectivity and good stability and has been used to determine pepsin in real samples with satisfactory results.

Changes of Pepsin Concentration in Saliva Sample According to Storage Period

OBJECTIVES

To determine whether the concentration of pepsin in the saliva sample changes according to the storage period of the sample.

METHODS

Forty eight patients with suspected laryngopharyngeal reflux were included in this study. Saliva samples were collected from each patient and each sample divided into six and stored for different period of time. Pepsin concentration was measured using enzyme-linked immunosorbent assay. A comparison was made between the pepsin concentration measured immediately and the concentration measured after storage for 1 week, 2 weeks, 1 month, 3 months, and 6 months.

RESULTS

No significant difference in pepsin concentrations were detected between the sample analyzed immediately and those analyzed at 1 week, 2 weeks, 1 month, and 3 months after saliva collection. A significant difference in pepsin concentration was observed in the sample analyzed immediately and the sample analyzed 6 months after saliva collection.

CONCLUSIONS

Pepsin concentration in saliva samples did not demonstrate a significant difference between the concentration measured immediately and the concentration measured 3 months after saliva collection, although a significant difference was observed in the concentration measured 6 months after collection.

The diagnostic value of pepsin concentration in saliva for laryngopharyngeal reflux disease

OBJECTIVE

To explore the diagnostic efficacy of pepsin concentration in saliva for laryngopharyngeal reflux (LPR) disease.

METHODS

In this study, we recruited 40 participants with abnormal sensation of throat into the study who visited our hospital from March 2020 to December 2020. The 24 h multichannel intraluminal impedance and pH monitoring (24 h MII-pH), reflux symptom index (RSI) and reflux finding score (RFS), pepsin concentration in saliva were collected. The Cohen's kappa test and receiver-operating characteristic (ROC) curves were performed to determine and compare the sensitivity and specificity of five diagnostic methods: RSI; RFS, pepsin concentration, RSI + RFS, RSI + RFS + pepsin concentration.

RESULTS

The area under the curve (AUC) of RSI, RFS, pepsin concentration, RSI + RFS, RSI + RFS + pepsin concentration were 0.767, 0.733, 0.870, 0.750,0.867, respectively. That is, the pepsin concentration has maximum AUC (the cutoff point is 219.47 (ng/mL); the sensitivity and 1-specificity is 0.300, 0.933, respectively.). The positive predictive value was 90.3% (28/31), and the negative predictive value was 77.8% (7/9). The Cohen's kappa coefficients of the five diagnostic subgroups were: RSI 0.486 (95% CI 0.207-0.764, P = 0.001); RFS 0.333 (95% CI 0.021-0.644, P = 0.032); RSI + RFS: 0.517 (95% CI 0.205-0.829, P = 0.001); pepsin concentration: 0.699 (95% CI 0.379-0.931, P = 0.001); RSI + RFS + pepsin concentration: 0.500 (95% CI 0.181-0.819, P < 0.001).

CONCLUSION

The pepsin concentration has the maximum AUC area and highest consistency with the 24 h MII-pH. Therefore, it has certain value in the screening and diagnosis of diseases related to LPR disease.

Diagnostic utility of salivary pepsin in laryngopharyngeal reflux: a systematic review and meta-analysis

OBJECTIVES

Salivary pepsin has emerged as a biomarker for Laryngopharyngeal Reflux (LPR), which, however, has been questioned for its efficacy due to a lack of supporting medical data. Therefore, this study analyzed the diagnostic value of salivary pepsin for LPR and assessed a better cutoff value.

METHODS

Studies were searched in PubMed, Embase, and Cochrane Library from their receptions to October 1, 2021. Then, RevMan 5.3 and Stata 14.0 were utilized to summarize the diagnostic indexes for further meta-analysis. Data were separately extracted by two reviewers according to the trial data extraction form of the Cochrane Handbook. The risk of bias in Randomized Control Trials (RCTs) was evaluated with the Cochrane Risk of Bias Tool.

RESULTS

A total of 16 studies matched the criteria and were subjected to meta-analysis. The results revealed a pooled sensitivity of 61% (95% CI 50%-71%), a pooled specificity of 67% (95% CI 48%-81%), a positive likelihood ratio of 2 (95% CI 1.2-2.8), a negative likelihood ratio of 0.58 (95% CI 0.47‒0.72), and the area under the receiver operating characteristic curve of 0.67 (95% CI 0.63‒0.71). Subgroup analyses indicated that the cutoff value of pepsin at 50 ng/mL had a higher degree of diagnostic accuracy than that of pepsin at 16 ng/mL in cohort studies.

CONCLUSION

The review demonstrated low diagnostic performance of salivary pepsin for LPR and that the cutoff value of 50 ng/mL pepsin had superior diagnostic accuracy. Nevertheless, the diagnostic value may vary dependent on the utilized diagnostic criteria. Therefore, additional research is needed on the improved way of identifying salivary pepsin in the diagnosis of LPR, and also longer-term and more rigorous RCTs are warranted to further assess the effectiveness of salivary pepsin.

Does hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring for the diagnosis of laryngopharyngeal reflux have to be 24 h?

PURPOSE

To investigate the diagnostic value of combined multi-timepoint salivary pepsin testing (MTPSPT) and hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring (HEMII-pH) for laryngopharyngeal reflux (LPR) and whether an appropriate reduction in the duration of HEMII-pH would affect the accuracy of diagnosis of LPR.

METHODS

Recruited patients were studied with both MTPSPT and HEMII-pH. The diagnosis of LPR was based on the occurrence of > 1 reflux event and/or positive results on any of the MTPSPT. The diagnostic value of combined diagnosis was studied through combining a breakdown of the 24-h HEMII-pH finding and the results of the MTPSPT. The diagnostic value was expressed in terms of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

Based on 24-h HEMII-pH and MTPSPT, the positive rate of LPR was 83.33% and 74.69%, respectively. According to the combined diagnosis, the positive rate of LPR was 90.74%. The sensitivity and specificity of the combined diagnosis both were 89.51% and 100%, when the HEMII-pH intervals were 7 a.m.-6 p.m. and 7 a.m.-7 p.m., respectively. However, when the monitoring time was extended to 8 p.m. and bedtime, the sensitivity, specificity, PPV and NPV of the combined diagnosis both were 100%.

CONCLUSIONS

The combination of MTPSPT and HEMII-pH increased the sensitivity and accuracy of diagnosis of LPR. For patients with positive MTPSPT results, the duration of HEMII-pH can be appropriately shortened to reduce patient sufferings.

Predictive Value of Laryngeal Mucosa Pepsin in Therapeutic Response of Laryngopharyngeal Reflux

OBJECTIVES/HYPOTHESIS

To investigate the predictive capability of pepsin level in the laryngeal mucosa to the therapeutic effect of proton-pump inhibitors in patients with suspected laryngopharyngeal reflux (LPR), so as to verify whether it can be referred to as a biomarker of LPR.

STUDY DESIGN

Prospective case study.

METHODS

Sixty patients with clinical empiric LPR were enrolled, with an reflux symptom index (RSI) ≥ 13 and an reflux finding score (RFS) > 7 as screening criteria. Biopsy specimens from the interarytenoid mucosa were obtained under topical anesthesia for pepsin immunohistochemical staining. Two parameters were observed in these patients with different pepsin levels after the administration of esomeprazole for 12 weeks: the RSI and the RFS.

RESULTS

Among the 60 cases, 35 cases were negative or weakly positive for pepsin (Pepsin(-) group), and 25 cases were moderately positive or strongly positive for pepsin (Pepsin(+) group). After therapy, the RSI significantly decreased from 17.00 (15.00, 19.00) to 6.00 (5.00, 11.00) in the Pepsin(+) group (Z = -4.38, P < 0.01), but no difference was found in the RFS (T = 1.48, P > 0.05). No significant difference was observed in the RSI (T = 2.01, P > 0.05) or the RFS (T = 2.01, P > 0.05) in the Pepsin(-) group either before or after therapy. An improvement in the RSI ≥ 50% was taken as the standard of effective therapy. The effective rate in the Pepsin(+) group was 72.0% (18/25), while it was 14.3% (5/35) in the Pepsin(-) group. There was a significant difference in the effective rate between the two groups (χ2 = 20.55, P < 0.01).

CONCLUSIONS

Proton-pump inhibitors exhibited better effects in patients with higher pepsin levels in the laryngeal mucosa. Laryngeal mucosa pepsin may serve as an ideal indicator to screen patients suitable for proton-pump inhibitor therapy and a reliable biomarker to identify patients with LPR.

Diagnostic Accuracy of Liquid Biomarkers in Airway Diseases: Toward Point-of-Care Applications

Background

Liquid biomarkers have shown increasing utility in the clinical management of airway diseases. Salivary and blood samples are particularly amenable to point-of-care (POC) testing due to simple specimen collection and processing. However, very few POC tests have successfully progressed to clinical application due to the uncertainty and unpredictability surrounding their diagnostic accuracy.

Objective

To review liquid biomarkers of airway diseases with well-established diagnostic accuracies and discuss their prospects for future POC applications.

Methodology

A literature review of publications indexed in Medline or Embase was performed to evaluate the diagnostic accuracy of liquid biomarkers for chronic obstructive pulmonary disease (COPD), asthma, laryngopharyngeal reflux (LPR), and COVID-19.

Results

Of 3,628 studies, 71 fulfilled the inclusion criteria. Sputum and blood eosinophils were the most frequently investigated biomarkers for the management of asthma and COPD. Salivary pepsin was the only biomarker with a well-documented accuracy for the diagnosis of LPR. Inflammatory blood biomarkers (e.g., CRP, D-dimers, ferritin) were found to be useful to predict the severity, complications, and mortality related to COVID-19 infection.

Conclusion

Multiple liquid biomarkers have well-established diagnostic accuracies and are thus amenable to POC testing in clinical settings.

Determination of pepsin by capillary electrophoresis using mixed polymer coated capillary with switchable properties towards protein adsorption/desorption

In this work, a simple on-line preconcentration method for quantitative detection of pepsin was realized by using the binary mixed polymer brushes coated capillary with switchable properties towards protein adsorption. Firstly, the binary mixed polymer brushes were prepared by grafting poly(2-methyl-2-oxazoline) and poly(4-vinylpyridine) onto the inner wall of the capillary through polydopamine anchor. Then the coatings were characterized by X-ray photoelectron spectrometer and electroosmotic flow measurement. The results indicated that the composition of coating could be controlled by varying the feed ratio of poly(2-methyl-2-oxazoline) to poly(4-vinylpyridine) and the inner surface charge could be tuned toward the change of pH and ionic strength. The results showed when poly(2-methyl-2-oxazoline)/poly(4-vinylpyridine) mass ratio was 80/20, the highest on-line preconcentration effect was obtained and the sensitivity enhancement factor was 6.3. Moreover, satisfactory sensitivity (limit of detection: 7.5 ng/mL) and good repeatability were obtained with on-line preconcentration method. The polymer coated capillary was still stable for on-line preconcentration and detection of pepsin after 50 consecutive runs. Lastly, the proposed method was used successfully to on-line preconcentrate pepsin in saliva matrix. This article is protected by copyright. All rights reserved.

Fasting salivary pepsin level as a reliable non-invasive method of screening for laryngopharyngeal reflux in Egyptian patients

Background

Laryngopharyngeal reflux (LPR) is caused by the regurgitation of gastric contents above the upper esophageal sphincter. Diagnostic gold standard tests like multichannel intraluminal impedance (MII) and 24-h dual-probe pH-metry are invasive and expensive which limits their accessibility especially in resource-limited settings. Since pepsin is only produced in the stomach, detecting pepsin in the laryngopharynx would make it a specific marker for reflux.

Therefore, in this study, we measured fasting salivary pepsin in patients with symptoms suggestive of LPR. We aimed to confirm the role of fasting salivary pepsin as a non-invasive diagnostic tool of LPR, to detect a cut-off value for it in Egyptian patients and to study predictors of changes in its level.

Methods

We conducted a prospective case control study at the gastroenterology clinic in Ain Shams University Hospitals. After testing with esophageal pH-metry, 25 symptomatic patients with confirmed LPR and 25 healthy controls were enrolled in the study. Patients diagnosed with organic upper gastrointestinal disorders, autoimmune diseases, diabetes, malignancy or organ failure were excluded. Patients on PPI were advised to stop 2 weeks before testing. All patients were tested for fasting salivary pepsin levels, esophageal pH-metry, and indirect laryngoscopy in addition to routine laboratory parameters.

Results

Out of the 25 LPR patients, 16% of patients had laryngoscope abnormality in the form of mucosal hyperemia and inflammation, and the average percentage of time pH < 4 in esophageal pH-metry testing was 29.14 ± 39.5%.

Comparative study between the 2 groups revealed a significant increase in salivary pepsin in LPR group compared to control group (p < 0.001). By using ROC-curve analysis, salivary pepsin at a cut-off point > 5 ng/ml diagnosed patients with LPR, with fair (77.9%) accuracy, sensitivity = 100% and specificity = 56% (p = 0.0001) while pH-metry (% Time pH < 4) at a cut-off point > 14% diagnosed patients with LPR, with good (87%) accuracy, sensitivity = 80%, and specificity = 100% (p < 0.0001)

Conclusion

Fasting salivary pepsin level at a cut-off value of > 5 ng/ml is a reliable, non-invasive method for detection of LPR especially in resource-limited settings.

Multitime point pepsin testing can double the rate of the diagnosis of laryngopharyngeal reflux

OBJECTIVE

To study the value of multitime point salivary pepsin testing (MTPSPT) for the diagnosis of laryngopharyngeal reflux (LPR).

STUDY DESIGN

Prospective noncontrolled.

METHODS

For patients who met the enrollment criteria, the reflux symptom index (RSI) and reflux finding score (RFS) were calculated and salivary pepsin testing was performed. The pepsin test was performed every hour from 7:00 a.m. to 6:00 p.m. by collecting fresh saliva samples. A single positive test result was needed for the diagnosis of LPR. The consistency in the diagnosis of LPR between the two methods was compared with the weighted Cohen's kappa statistic.

RESULTS

A total of 204 patients were included. The kappa value between the two methods was 0.566 (p = .00). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MTPSPT were 76.43%, 85.94%, 92.24%, and 62.5%, respectively. We also compared a single pepsin measure at 7 a.m. with the screening results based on the RSI and RFS, and found a much lower kappa agreement value (0.223, p = .00). The sensitivity, specificity, PPV, NPV, and false-negative rate of pepsin testing at 7 a.m. (fasting) were 37.86%, 92.18%, 91.38%, 40.41%, and 58.57%, respectively.

CONCLUSION

The use of the result of a single salivary pepsin test in the morning yields a relatively higher rate of missed diagnosis of LPR, and multitime point testing through a day increased the accuracy and sensitivity of detection of LPR twofold compared to a single morning fasting sample.

LEVEL OF EVIDENCE

3.

Pepsin A in Tracheal Secretions From Patients Receiving Mechanical Ventilation

BACKGROUND

In patients in the intensive care unit (ICU) receiving mechanical ventilation, aspiration of gastric contents may lead to ventilator-associated events and other adverse outcomes. Pepsin in pulmonary secretions is a biomarker of microaspiration of gastric contents.

OBJECTIVES

To evaluate the association between tracheal pepsin A and clinical outcomes related to ventilator use.

METHODS

A subset of 297 patients from a larger clinical trial on aspiration of oral secretions in adults receiving mechanical ventilation consented to have pepsin A measured in their tracheal aspirate samples. A concentration ≥6.25 ng/mL indicated a positive result. Abundant microaspiration was defined as pepsin A in ≥30% of samples. Statistical analyses included analysis of variance, analysis of covariance, and χ2 tests.

RESULTS

Most patients were White men, mean age 59.7 (SD, 18.8) years. Microaspiration was found in 43.8% of patients (n = 130), with abundant microaspiration detected in 17.5% (n = 52). After acuity was controlled for, patients with tracheal pepsin A had a longer mechanical ventilation duration (155 vs 104 hours, P < .001) and ICU stay (9.9 vs 8.2 days, P = .04), but not a longer hospital stay.

CONCLUSIONS

Microaspiration of gastric contents occurred in nearly half of patients and was associated with a longer duration of mechanical ventilation and a longer stay in the ICU. Additional preventative interventions beyond backrest elevation, oropharyngeal suctioning, and management of endotracheal tube cuff pressure may be needed. Also, the timing of pepsin measurements to capture all microaspiration events requires additional exploration.

Association of Pepsin With Inflammatory Signaling and Effusion Viscosity in Pediatric Otitis Media

OBJECTIVE

Otitis media (OM) is a common inflammatory disease spectrum. Cytokine signaling, neutrophil activity, and mucin hypersecretion during recurrent and chronic OM contribute to persistent, viscous middle ear (ME) effusions, hearing loss, and potential for developmental delay. Extraesophageal reflux (EER), specifically pepsin, triggers inflammatory signaling in respiratory mucosa and is associated with OM. The objective of this study was to investigate the association of pepsin with ME inflammatory signaling and the outcomes and examine causality in vitro.

STUDY DESIGN

Cross-sectional study.

METHODS

ME fluid (MEF) and preoperative audiometric data were collected from 30 pediatric subjects undergoing tympanostomy tube placement for recurrent OM or OM with effusion. MEF viscosity was characterized by the surgeon. Pepsin, inflammatory molecules, and mucin were assayed by enzyme-linked immunosorbent assay (ELISA). ME epithelial primary culture was exposed to 0.1 to 1 mg/ml pepsin at pH 5, 6, and 7 for 30 minutes, and cytokine expression was assayed via qPCR.

RESULTS

Pepsin was observed in the MEF of 77% of patients (range 71-2,734 ng/ml). Pepsin correlated with effusion viscosity, interleukins -6 and -8, neutrophil elastase, and mucin 5B (P < .05). Pepsin-negative MEF was more frequently absent of interleukin 8 or mucin 5B (P < .05). Weak acid was generally insufficient to elicit cytokine expression in ME cells in vitro, however, pepsin induced IL6, IL8, and TNF at pH 7 (P < .05) and weak acid (pH 6) facilitated a response at lower pepsin concentration.

CONCLUSIONS

Pepsin may contribute to inflammatory signaling, persistent viscous effusion, and poorer OM outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Proteomic Characterization of Canine Gastric Fluid by Liquid Chromatography-Mass Spectrometry for Development of Protein Biomarkers in Regurgitation, Vomiting, and Cough

Reflux and aspiration in people cause and exacerbate respiratory diseases in the absence of gastrointestinal signs. Protein biomarkers in humans detect extraesophageal reflux (EER) from oropharyngeal (OP) and bronchoalveloar lavage samples. Reflux likely contributes to respiratory disease in dogs. The objectives of this study were to analyze the canine gastric fluid (GF) proteome and compare this to the OP proteome in normal, vomiting/regurgitating, and coughing dogs to identify biomarkers for EER/aspiration. Twenty-three client-owned dogs were enrolled. Canine GF samples (n = 5) and OP swabs in normal (n = 6), vomiting/regurgitating (n = 7), and coughing (n = 5) dogs were within 2 weeks of sample collection. Protein digests were analyzed by liquid chromatography–mass spectrometry. Differential abundance (DA) of proteins between groups was evaluated by Fisher's exact test with p < 0.0004 significance level after correction for multiple comparisons. DA was found between all groups (p < 0.0001): GF vs. normal (n = 130 proteins), coughing vs. normal (n = 22 proteins), and vomiting/regurgitating vs. normal (n = 20 proteins). Protein abundance was highly variable between dogs. Gastrointestinal-specific proteins were found in OP swabs from vomiting/regurgitating and coughing dogs but not from healthy dogs. In conclusion, the proteomic composition of the OP varies between health and disease. The presence of gastrointestinal-specific proteins in OP of coughing dogs may suggest reflux and/or aspiration as contributing factors. The variable protein abundance warrants investigation into biomarker panels.

Pepsin Promotes Activation of Epidermal Growth Factor Receptor and Downstream Oncogenic Pathways, at Slightly Acidic and Neutral pH, in Exposed Hypopharyngeal Cells

Pepsin refluxate is considered a risk factor for laryngopharyngeal carcinogenesis. Non-acidic pepsin was previously linked to an inflammatory and tumorigenic effect on laryngopharyngeal cells in vitro. Yet there is no clear evidence of the pepsin-effect on a specific oncogenic pathway and the importance of pH in this process. We hypothesized that less acidic pepsin triggers the activation of a specific oncogenic factor and related-signalling pathway. To explore the pepsin-effect in vitro, we performed intermittent exposure of 15 min, once per day, for a 5-day period, of human hypopharyngeal primary cells (HCs) to pepsin (1 mg/mL), at a weakly acidic pH of 5.0, a slightly acidic pH of 6.0, and a neutral pH of 7.0. We have documented that the extracellular environment at pH 6.0, and particularly pH 7.0, vs. pH 5.0, promotes the pepsin-effect on HCs, causing increased internalized pepsin and cell viability, a pronounced activation of EGFR accompanied by NF-κB and STAT3 activation, and a significant upregulation of EGFR, AKT1, mTOR, IL1β, TNF-α, RELA(p65), BCL-2, IL6 and STAT3. We herein provide new evidence of the pepsin-effect on oncogenic EGFR activation and its related-signaling pathway at neutral and slightly acidic pH in HCs, opening a window to further explore the prevention and therapeutic approach of laryngopharyngeal reflux disease.

Evidence of Pepsin-Related Ocular Surface Damage and Dry Eye (PROD Syndrome) in Patients with Laryngopharyngeal Reflux

Background: patients with laryngopharyngeal reflux (LPR) showed detectable levels of tear pepsin that explain the nasolacrimal obstruction. The purpose of this study was to determine whether patients with LPR show ocular surface changes and to investigate the relationship between lacrimal pepsin concentration and ocular alterations. Methods: Fifty patients with positive endoscopic signs for LPR and an equal or higher score of 13 and 7 for Reflux Symptom Index and Reflux Finding Score were enrolled. Twenty healthy patients with no reflux disease and dry eye were included as the control group. After evaluation of ocular discomfort symptoms, the tear break-up time test, corneal staining, and tear sampling were performed. Tear pepsin levels were measured using Pep-test^TM kit. Results: Patients with LPR showed ocular surface changes including epithelial damage (48%) and impairment of lacrimal function (72%). Tear pepsin levels were detectable in 32 out of 50 (64%) patients with LPR (mean ± SD: 55.4 ± 67.5 ng/mL) and in none of the control subjects. Most of the LPR patients complained of ocular discomfort symptoms, including itching (38%), redness (56%), or foreign body sensation (40%). Tear pepsin levels were significantly correlated with the severity of LPR disease and with ocular surface changes. Conclusions: A multidisciplinary approach, including ophthalmological evaluation, should be considered in order to improve the management of patients with LPR.

Pepsin and Laryngeal and Hypopharyngeal Carcinomas

Laryngeal and hypopharyngeal carcinomas are common malignant tumors of the head and neck, and the incidence of both is increasing. Laryngopharyngeal reflux refers to the retrograde flow of gastric contents into the larynx, oropharynx, and/or nasopharynx. It remains controversial whether laryngopharyngeal reflux is a risk factor for laryngeal and hypopharyngeal cancers. The refluxing substances mainly include hydrochloric acid, pepsin, and occasionally bile acids and bile salts, as well as bacteria that colonize the gastrointestinal tract. Loss of epithelium in the mucous membrane of the larynx and hypopharynx is thought to be caused by pepsin. Here, we review the relationships between laryngopharyngeal reflux and both laryngeal and hypopharyngeal carcinomas, as well as the significance of pepsin, methods of clinical detection, and the mechanism of carcinogenesis.

Laryngopharyngeal Reflux: Symptoms, Signs, and Presence of Pepsin in Saliva - A Reliable Diagnostic Triad

Introduction  Twenty-four-hour multichannel intraluminal impedance with double probe pH monitoring (MII-pH), though considered the most sensitive tool for the diagnosis of gastroesophageal reflux disease (GERD), is invasive, time consuming, not widely available, and unable to detect non-acid reflux. In contrast, the presence of pepsin in the saliva would act as a marker for reflux, considering that pepsin is only produced in the stomach.

Objective  To evaluate the predictive value of salivary pepsin in diagnosing laryngopharyngeal reflux (LPR) as suggested by the results of reflux symptom index (RSI > 13), reflux finding score (RFS > 7), and positive response to treatment with a 4-week course of proton-pump inhibitors.

Methods  This prospective study was done at a tertiary care hospital on 120 adult patients attending ENT OPD with clinical diagnosis of LPR. The presence of pepsin in their pharyngeal secretions and saliva using a lateral flow device, the Peptest, was compared with RSI, RFS, and with the response to medical treatment using the Chi-squared test.

Results  Salivary pepsin was found to be positive in 68% of the patients, with 87.5% of them showing positive response to treatment. Chi-squared analysis showed a significant association between positive salivary pepsin and RFS > 7, RSI >13, a combination of RFS > 7 and RSI > 13 as well as with response to treatment ( p  < 0.0001).

Conclusion  When considered along with the clinical indicators of RFS and RSI of more than 7 and 13, respectively, and/or with a response to treatment, a positive salivary pepsin test indicates statistically significant chance of presence of LPR.

Usefulness of Pep-Test for Laryngo-Pharyngeal Reflux: A Pilot Study in Primary Care

Background

Gastroesophageal reflux disease is a digestive disorder characterized by nausea, regurgitation, and heartburn. Gastroesophageal reflux is the primary cause of laryngeal symptoms, especially chronic posterior laryngitis. The best diagnostic test for this disease is esophageal impedance-pH monitoring; however, it is poorly employed owing to its high cost and invasiveness. Salivary pepsin measured using a lateral flow device (Pep-test) has been suggested as an indirect marker of laryngopharyngeal reflux (LPR). The present study tested the reliability of Pep-test in diagnosing LPR in uninvestigated primary care attenders presenting with chronic laryngeal symptoms, and evaluated the raw pepsin concentration in patients with LPR.

Methods

A multicenter, non-interventional pilot study was conducted on 86 suspected patients with LPR and 59 asymptomatic subjects as controls in three Italian primary care settings. A reflux symptom index questionnaire was used to differentiate patients with LPR (score >13) from controls (score <5). Two saliva samples were collected, and comparisons between the groups were performed using two-sided statistical tests, according to variable distributions.

Results

There was no statistical difference in the salivary pepsin positivity between LPR patients and controls, whereas the pepsin intensity value was higher in controls than in LPR patients.

Conclusion

A high prevalence of pepsin positivity was observed in asymptomatic controls. Pepsin measurement should not be considered as a diagnostic test for LPR in primary care patients.

Laryngopharyngeal Reflux and Atypical Gastroesophageal Reflux Disease

Laryngopharyngeal reflux and atypical manifestations of gastroesophageal reflux disease have a high economic and social burden in the United States. There is increasing research supporting the reflex theory and hypersensitivity syndrome underlying this disease pathophysiology. Novel diagnostic biomarkers have gained more traction in the search for a more reliable diagnostic tool, but further research is needed. Current standard-of-care treatment relies on proton pump inhibitor therapy. Antireflux surgery is usually not recommended. Neuromodulators and treatments targeting specific neuronal receptors are discussed. A diagnostic algorithm is proposed for the evaluation of laryngeal symptoms suspected to be related to extraesophageal reflux disease.

Pepsin promotes laryngopharyngeal neoplasia by modulating signaling pathways to induce cell proliferation

Pepsin plays an important role in laryngopharyngeal reflux (LPR), a risk factor for the development of hypopharyngeal squamous cell carcinomas (HPSCC). However, the role of pepsin in HPSCC is not clear. We show by immunohistochemistry that pepsin positivity occurs in a significant proportion of human primary HPSCC specimens, and in many cases matched adjacent uninvolved epithelia are negative for pepsin. Pepsin positivity is associated with nodal involvement, suggesting that pepsin may have a role in metastasis. Treatment of FaDu cancer cells with pepsin increased cell proliferation, possibly by inducing G1/S transition. We also observed significant changes in expression of genes involved in NF-kappaB, TRAIL and Notch signaling. Our data suggest that pepsin plays an important role in HPSCC and that targeting pepsin could have potential therapeutic benefits.

Optimization of Saliva Collection and Immunochromatographic Detection of Salivary Pepsin for Point-of-Care Testing of Laryngopharyngeal Reflux

Salivary pepsin is a promising marker for the non-invasive diagnosis of laryngopharyngeal reflux (LPR). For reliable results regarding pepsin in saliva, it is critical to standardize the collection, storage, and pre-processing methods. In this study, we optimized the saliva collection protocols, including storage conditions, i.e., solution, temperature, and time, and the pre-processing filter for pepsin. Moreover, we prepared a simple immunochromatographic strip for the rapid detection of pepsin and evaluated its sensing performance. As a result, we selected a polypropylene (PP) filter as the pre-processing filter for salivary pepsin in low resource settings, such as those where point of care testing (POCT) is conducted. This filter showed a similar efficiency to the centrifuge (standard method). Finally, we detected the pepsin using gold nanoparticles conjugated with monoclonal pepsin antibody. Under optimized conditions, the lower limit of detection for pepsin test strips was determined as 0.01 μg/mL. Furthermore, we successfully detected the salivary pepsin in real saliva samples of LPR patients, which were pre-processed by the PP filter. Therefore, we expect that our saliva collection protocol and pepsin immunochromatographic strip can be utilized as useful tools for a non-invasive diagnosis/screening of LPR in POCT.

Duodenogastroesophageal reflux and its effect on extraesophageal tissues: A review

We conducted a literature review to identify elements of duodenogastroesophageal reflux (DGER)—namely pancreatic fluids, hydrochloric acid, pepsin, and bile—as to the effects each has when refluxed to the extraesophageal structures. Further, we wished to acquaint clinicians with the possibilities that, in addition to hydrochloric acid, the other components of DGER are likewise contributing to disease in the extraesophageal areas. Our review included studies that have indicated reflux of the above mentioned components of DGER to the pharynx, larynx, tracheobronchial tree, oral cavity, nasopharynx, nose and sinuses, eustachian tube, and middle ear. Findings demonstrate that injury to the upper aerodigestive tract can occur from a variety of substances secreted from the stomach and duodenum. Treatment for DGER is nonspecific. We conclude that patients with an incomplete response to acid suppression may have significant involvement of pepsin, bile, or both. Future studies are needed to clarify the importance of these elements and to suggest more precise treatments.

Pepsin and oropharyngeal pH monitoring to diagnose patients with laryngopharyngeal reflux

Objectives

The aim of this study was to compare the diagnostic accuracy of salivary pepsin with oropharyngeal pH monitoring using the Restech measurement system (Dx‐pH) for the diagnosis of laryngopharyngeal reflux (LPR).

Study Design

Prospective cohort study.

Methods

Seventy patients with primary symptoms related to LPR underwent gastroscopy, high‐resolution manometry, pH throughout 24‐hour monitoring (MII‐pH), and barium esophagography between October 2015 and May 2018. In addition, an ear, nose, and throat examination was performed, including assessment of Belafsky Reflux Finding Score (RFS). Clinical symptoms were evaluated with the Belafsky Reflux Symptom Index (RSI) and the Gastrointestinal Quality of Life Index (GIQLI). Simultaneous to MII‐pH, pepsin determination and Dx‐pH were performed.

Results

Of 70 patients, 41 (58.6%) subjects with a pathological DeMeester score showed higher mean values of pepsin (mean value: 216 ng/mL, 95% confidence interval [CI]: 172 to 260), compared to patients with a normal DeMeester score (mean value: 161 ng/mL, 95% CI: 115 to 207). Salivary pepsin showed a specificity of 86.2% and sensitivity of 41.5% for diagnosing LPR using the optimal cutoff value of 216 ng/mL. Furthermore, a significant correlation between the values of salivary pepsin and the RSI score was seen in patients with pathological results in MII‐pH (r = 0.344; P = 0.046).

However, elevated Dx‐pH measurements showed no significant correlation with either MII‐pH, RSI score, RFS score, or GIQLI score, or with the results of pepsin measurement.

Conclusion

Pepsin measurement in saliva could be an alternative tool to assist office‐based diagnosis of LPR, whereas Dx‐pH does not seem to be an adequate test.

Level of Evidence

2B Laryngoscope, 130:1780–1786, 2020

Pepsin Triggers Neutrophil Migration Across Acid Damaged Lung Epithelium

Pepsin represents a potential biomarker for extraesophageal reflux disease when detected in airways, however a direct role for pepsin in lung dysfunction has not been clearly established. Children experiencing gastroesophageal and extraesophageal reflux are often prescribed proton pump inhibitors (PPIs) to reduce gastric acid associated damage to esophageal and airway mucosa. The potential of pepsin and gastric fluid, from children that were either on or off PPI therapy, to cause inflammation and damage using a human in vitro co-culture model of the airway mucosa was evaluated herein. Exposure of the airway model to acidic solutions caused cellular damage and loss of viability, however, acid alone did not disrupt barrier integrity or instigate neutrophil trans-epithelial migration without pepsin. Gastric fluid from patients on PPI therapy exhibited only a slightly higher pH yet had significantly higher concentrations of pepsin and elicited more barrier disruption and neutrophil trans-epithelial migration compared to gastric fluid from patients off PPIs. Inflammatory and damaging responses observed with gastric fluid from patients on PPIs were largely driven by pepsin. These results indicate the potential for PPI usage to raise concentrations of pepsin in gastric fluid, which may enhance the pathological impact of micro-aspirations in children with extraesophageal reflux.

Correlation of salivary and nasal lavage pepsin with MII-pH testing

OBJECTIVES

Laryngopharyngeal reflux (LPR) is a common upper airway disease. Salivary pepsin is a proposed marker for LPR; however, the optimal time for collection of specimens for pepsin detection and pepsin's presence in the oral and nasal secretions relative to concurrent multichannel intraluminal impedance-pH (MII-pH) monitoring are unknown.

STUDY DESIGN

Prospective case-control study with an experimental design.

METHODS

Patients undergoing MII-pH testing for evaluation of LPR and asymptomatic control subjects were selected. Nasal lavage and saliva samples were collected in the clinic prior to MII-pH probe placement. Additional saliva samples were obtained an hour after each meal and upon waking the following morning. Nasal lavage and salivary pepsin were measured by ELISA.

RESULTS

Twenty-six patients undergoing MII-pH testing and 13 reflux-free control patients were enrolled. Salivary pepsin was detected in 11 of 26 patients with suspected LPR and 0 of 13 controls. Pepsin was most frequently detected in the specimen provided upon waking at an average concentration of 186.9 ng/mL. A significant correlation was observed between salivary pepsin in waking samples to MII-pH measurements, including reflux bolus duration, and proximal and distal recumbent reflux episodes (P < 0.05). A significant correlation was also observed between salivary pepsin upon waking or sinus lavage and reflux symptom index (P < 0.05).

CONCLUSION

Pepsin in salivary and nasal lavage samples demonstrated an association with MII-pH-documented LPR. Pepsin detection was most frequent in morning samples, supporting use of morning salivary pepsin levels as a potential noninvasive technique for LPR diagnosis.

LEVEL OF EVIDENCE

2 Laryngoscope, 130:961-966, 2020.

Laryngopharyngeal Reflux Diagnosis in Obstructive Sleep Apnea Patients Using the Pepsin Salivary Test

Background: To investigate the presence of laryngopharyngeal reflux in patients with obstructive sleep apnea (OSA) employing the salivary pepsin concentration method. To compare the results of pepsin concentration with the severity of the pathology. Methods: Seventy-five OSA patients (44 males, 31 females) were enrolled in the study. For each patient, the AHI (apnea–hypopnea index) and the BMI (body mass index) were initially evaluated. All the patients enrolled were assessed using the reflux symptom index (RSI) and the reflux finding score (RFS) in order to perform a clinical diagnosis of laryngopharyngeal reflux. In all patients a salivary sample was taken to estimate the presence of pepsin and its concentration. Results: The incidence of LPR (laryngopharyngeal reflux) in OSA patients, evaluated using the salivary pepsin concentration test (PEP-test), was found to be 32% of cases. Linear regression testing did not show any correlation between AHI and pepsin concentration in salivary samples (p = 0.1). Conclusion: A high number of patients with OSA seem to show positivity for salivary pepsin, correlated to an LPR. There does not appear to be a correlation between the severity of apnea and the grade of salivary pepsin reflux. On the other hand, direct correlation between BMI and the value of pepsin in salivary specimens was observed.

Detection of pepsin and IL-8 in saliva of adult asthmatic patients

Objective: Asthma and gastric reflux disease are widespread and often coexisting diseases with complex interactions, leading some to suspect that asthma symptoms of patients with reflux may improve with anti-reflux therapy. The objective of this study was to determine whether pepsin in saliva, indicative of airway reflux, could be detected in patients with asthma of varying severity and test the requirement of citric acid as a pepsin preservative. Methods: Saliva samples were collected in the clinic (with/without citric acid) and upon waking the following morning from 25 asthmatic patients. Enzyme-linked immunosorbent assay was performed for pepsin and interleukin-8 (IL-8), an inflammatory cytokine induced by pepsin in other airway epithelia. Pepsin induction of IL-8 was tested in a lung epithelial cell culture model. Results: Pepsin was detected in saliva from 14/25 patients (56%; mean concentration of pepsin in specimens where observed ±SD =80.3±87.5 ng/mL); significant agreement was found between samples collected in the presence/absence of citric acid. No significant associations were found with pepsin and clinical measures of asthma severity. IL-8 was detected in saliva from 22/25 patients (88%; mean IL-8 in all specimens where observed =3.27±3.91 ng/mL). IL-8 was significantly upregulated in human lung epithelial cells exposed to pepsin at pH7 in vitro (P=0.041). Conclusion: In summary, more than half of the asthma patients in this study were found to have pepsin in their saliva, indicative of airway reflux. These data support the use of salivary pepsin as a noninvasive tool for future investigation of airway reflux in a larger cohort. The data further suggest that collection in citric acid as a sample preservative is not warranted and that pooling of multiple saliva samples collected at various timepoints may improve sensitivity of pepsin detection and reduce costs incurred by multiple sample analysis in future studies.

Pepsin promotes IL-8 signaling-induced epithelial-mesenchymal transition in laryngeal carcinoma

Background

Laryngopharyngeal reflux (LPR), with its increasing morbidity, is attracting considerable attention. In recent years, the causal role between LPR and laryngeal carcinoma has been debated. The main harmful component of LPR is pepsin, which has been shown to induce mucosal inflammation by damaging the mucous membrane. Thus, pepsin is linked to an increased risk of laryngeal carcinoma, although the potential mechanism remains largely unknown.

Methods

The human laryngeal carcinoma cell lines Hep-2 and Tu212 were exposed to different pepsin concentrations and the morphology, proliferation, migration, secretion of inflammatory cytokines, and epithelial–mesenchymal transition (EMT) of the cells were assessed. To evaluate whether interleukin-8 (IL-8) had a causal relationship with pepsin and EMT, an IL-8 inhibitor was used to suppress IL-8 secretion during pepsin exposure and the expression of EMT markers, cell proliferation, and migration were analyzed.

Results

Pepsin promoted proliferation, colony formation, migration, and IL-8 secretion of Hep-2 and Tu212 cells in vitro. Furthermore, increased pepsin concentrations changed the morphology of Hep-2 and Tu212 cells; levels of the epithelial marker E-cadherin were reduced and those of mesenchymal markers vimentin and β-catenin and the transcription factors snail and slug were elevated. A similar effect was observed in laryngeal carcinoma tissues using immunohistochemistry. IL-8 level was reduced and EMT was restored when pepsin was inhibited by pepstatin. EMT was weakened after exposure to the IL-8 inhibitor, with significant reduction in pepsin-induced cell proliferation and migration.

Conclusions

Pepsin may induce EMT in laryngeal carcinoma through the IL-8 signaling pathway, which indicates that it has potential role in enhancing cell proliferation and metastasis of laryngeal carcinoma.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0772-7) contains supplementary material, which is available to authorized users.

Reflux aspiration in lungs of dogs with respiratory disease and in healthy West Highland White Terriers

BACKGROUND

Gastroesophageal reflux and microaspiration (MA) of gastric juice are associated with various human respiratory diseases but not in dogs.

OBJECTIVE

To detect the presence of bile acids in bronchoalveolar lavage fluid (BALF) of dogs with various respiratory diseases.

ANIMALS

Twenty-seven West Highland White Terriers (WHWTs) with canine idiopathic pulmonary fibrosis (CIPF), 11 dogs with bacterial pneumonia (BP), 13 with chronic bronchitis (CB), 9 with eosinophilic bronchopneumopathy (EBP), 19 with laryngeal dysfunction (LD), 8 Irish Wolfhounds (IWHs) with previous BPs, 13 healthy WHWTs, all privately owned dogs, and 6 healthy research colony Beagles METHODS: Prospective cross-sectional observational study with convenience sampling of dogs. Bile acids were measured by mass spectrometry in BALF samples. Total bile acid (TBA) concentration was calculated as a sum of 17 different bile acids.

RESULTS

Concentrations of TBA were above the limit of quantification in 78% of CIPF, 45% of BP, 62% of CB, 44% of EBP, 68% of LD, and 13% of IWH dogs. In healthy dogs, bile acids were detected less commonly in Beagles (0/6) than in healthy WHWTs (10/13). Concentrations of TBA were significantly higher in CIPF (median 0.013 μM, range not quantifiable [n.q.]-0.14 μM, P < .001), healthy WHWTs (0.0052 μM, n.q.-1.2 μM, P = .003), LD (0.010 μM, n.q.-2.3 μM, P = .015), and CB (0.0078 μM, n.q.-0.073 μM, P = .018) groups compared to Beagles (0 μM, n.q.).

CONCLUSION AND CLINICAL IMPORTANCE

These results suggest that MA occurs in various respiratory diseases of dogs and also in healthy WHWTs.

The Diagnostic Usefullness of the Salivary Pepsin Test in Symptomatic Laryngopharyngeal Reflux

OBJECTIVE

Laryngopharyngeal Reflux (LPR) is a disease characterized by the presence of symptoms, signs and tissue alterations in the aero-digestive upper tract as a consequence of the gastric contents retrograde movement. In most cases diagnosis is clinical and it is established by the presence of symptoms and endoscopic laryngeal signs. The aim of the study was to determine the sensitivity, specificity, positive and negative Likelihood Ratio (LR) of the salivary pepsin assay (PEP-test, RD Biomed, Hull, UK) as diagnostic tool of LPR.

STUDY DESIGN

Diagnostic Accuracy Study.

METHOD

221 subjects aged between 26 and 68 years were recruited. All subjects completed the Reflux Symptom Index scale. PEP-test was carried out on fasting subjects, and a second test was performed one hour after the main meal, only on those subjects with a fasting negative result.

RESULTS

Fasting PEP-test showed a 98% specificity, 40% sensitivity, positive LR of 16.4 and negative LR of 0.61. The use of both PEP-test showed a 95% specificity, 48% sensitivity, positive LR of 9.61 and negative LR of 0.55.

CONCLUSIONS

The PEP-test is a simple, inexpensive, non-invasive and easily reproducible test that should be considered as an alternative diagnosis tool for LPR diagnosis. When there is a clinical suspicion of LPR disease, a positive result on the test could be considered diagnostic, but on subjects with negative results it should be complemented with more complex tests such as the 24-hour dual-channel pH-metry.

Saliva Pepsin Detection and Proton Pump Inhibitor Response in Suspected Laryngopharyngeal Reflux

OBJECTIVES/HYPOTHESIS

To evaluate the prediction value of saliva pepsin detection for an 8-week proton pump inhibitor (PPI) response in patients with a Reflux Symptoms Index (RSI) score ≥13, which indicates possible laryngopharyngeal reflux.

STUDY DESIGN

Prospective individual single-cohort study.

METHODS

Patients were recruited who had experienced chronic laryngopharyngeal symptoms (RSI score ≥13) for more than 3 months after excluding other etiologies. The patients received PPI (40 mg of esomeprazole once daily) treatment for 8 weeks. Prior to treatment, the patients submitted saliva/sputum samples that were collected during the time symptoms were observed. The samples were taken for pepsin detection, and performed using the commercially available Peptest lateral flow device. The association of the Peptest results and PPI response were statistically analyzed with the χ² test.

RESULTS

Seventy-four patients completed the study, and upon completion of PPI treatment, the mean RSI score was significantly reduced from 19.22 ± 5.18 to 8.99 ± 5.69. Forty-four (59.5%) patients exhibited a good response as defined by an RSI score reduction ≥50%. The results of the Peptest were semiquantitatively graded as 0, 1, 2, 3 (negative, weak positive, moderate positive and strong positive, respectively) based upon the visual intensity of the test sample line as compared to the control line. Twenty-four patients (32.4%) exhibited grade 3 strong positive results. The Peptest strong positive results (P < .05) were significantly associated with a good PPI response, with the positive predictive value being 79.2%.

CONCLUSIONS

Analysis of strong positive results for pepsin detection in saliva/sputum samples may be a useful, noninvasive method for predicting better PPI response in patients with suspected reflux induced chronic laryngopharyngeal symptoms.

LEVEL OF EVIDENCE

2 Laryngoscope, 129:709-714, 2019.

Assessment of the Acute Effects of Carbonated Beverage Consumption on Symptoms and Objective Markers of Gastric Reflux

Previous studies have suggested that carbonated beverages may cause gastro-oesophageal reflux. Pepsin (the major enzyme secreted by the stomach) has been suggested to be an objective, acute marker of a reflux event. This pilot study aimed to investigate whether intake of carbonated beverages could affect pepsin concentration in saliva or reflux symptoms. This was assessed by a randomised, crossover trial where participants consumed 330 mL of beverage (carbonated cola, degassed cola or water) at separate visits. Saliva samples and symptom questionnaires were collected at baseline and over the 30 min postprandial period. Pepsin was detected in all saliva samples. No difference was found in the salivary pepsin concentrations between treatments at all time points. There were significantly higher scores (p > 0.05) for feelings of fullness, heartburn, urge to belch and frequency of belches after ingestion of carbonated cola than degassed cola and water. The ingestion of carbonated beverages did not appear to increase postprandial pepsin concentration in saliva compared to other beverages but did evoke higher levels of reflux-related symptoms such as fullness, heartburn and belching. This suggests carbonated beverages may cause symptoms associated with reflux but do not drive detectable levels of gastric juice to reach the oral cavity.

Label-Free Detection of Salivary Pepsin Using Gold Nanoparticle/Polypyrrole Nanocoral Modified Screen-Printed Electrode

Detection of salivary pepsin has been given attention as a new diagnostic tool for laryngopharyngeal reflux (LPR) disease, because saliva collection is non-invasive and relatively comfortable. In this study, we prepared polypyrrole nanocorals (PPNCs) on a screen-printed carbon electrode (SPCE) by a soft template synthesis method, using &beta;-naphthalenesulfonic acid (NSA) (for short, PPNCs/SPCE). Gold nanoparticles (GNPs) were then decorated on PPNCs/SPCE by electrodeposition (for short, GNP/PPNCs/SPCE). To construct the immunosensor, pepsin antibody was immobilized on GNP/PPNCs/SPCE. Next, citric acid was applied to prevent non-specific binding and change the electrode surface charge before pepsin incubation. Electrochemical stepwise characterization was performed using cyclic voltammetry, and immunosensor response toward different pepsin concentrations was measured by differential pulsed voltammetry. As a result, our electrochemical immunosensor showed a sensitive detection performance toward pepsin with a linear range from 6.25 to 100 ng/mL and high specificity toward pepsin, as well as a low limit of detection of 2.2 ng/mL. Finally, we quantified the pepsin levels in saliva samples of LPR patients (n = 2), showing that the results were concordant with those of a conventional ELISA method. Therefore, we expect that this electrochemical immunosensor could be helpful for preliminarily diagnosing LPR through the detection of pepsin in saliva.

Sep70/Pepsin expression in hypopharynx combined with hypopharyngeal multichannel intraluminal impedance increases diagnostic sensitivity of laryngopharyngeal reflux

BACKGROUND

Improved methods of diagnosis of laryngopharyngeal reflux (LPR) would enable surgeons to better identify patients who may benefit from antireflux surgery (ARS). The objective of the present study was to assess if hypopharyngeal Pepsin and Sep70 expression combined with hypopharyngeal multichannel intraluminal impedance (HMII) has the potential to increase diagnostic sensitivity of LPR.

METHODS

This study was performed on patients who underwent unsedated transnasal endoscopy with hypopharyngeal biopsy and 24-h HMII to determine abnormal proximal exposure (APE) and DeMeester score (DMS) from 2013 to 2016. Pepsin and Sep70 protein expression was assessed by Western blots of biopsy specimens. The outcomes of ARS were assessed using reflux symptom index (RSI). HMII APE classification, Sep 70, and Pepsin protein levels were compared in normative and symptomatic LPR patients and further analyzed alongside quality of life changes following ARS.

RESULTS

Of 30 subjects enrolled, 23 were excluded for abnormal HMII results or endoscopic evidence of esophagitis. Seven subjects and 105 patients were included in the normative and symptomatic groups, respectively. Compared to the normative group, only Pepsin expression was significantly higher in the symptomatic group [APE+/LPR+ (p = 0.000), APE+/LPR- (p = 0.001), and APE- (p = 0.047)]. Further, the ratio of Sep70/Pepsin was significantly lower in the symptomatic group [APE+/LPR+ (p = 0.008), APE+/LPR- (p = 0.000), and APE- (p = 0.050)], and a cutoff ratio for a diagnosis of LPR was established as < 158. Of 105 symptomatic patients, 48 patients underwent ARS. Of these, 17 patients had complete pre- and post-RSI questionnaires. LPR symptoms improved in 15 (88%), of whom 2 were APE- but met criteria for a diagnosis of LPR based on the Sep70/Pepsin cutoff.

CONCLUSIONS

The identified Sep70/Pepsin ratio may serve as a reliable biomarker for the diagnosis of LPR. As a result, this may help identify additional patients who have a false-negative HMII result due to the 24-h testing window.

Relationship Between Salivary Pepsin Concentration and Esophageal Mucosal Integrity in Patients With Gastroesophageal Reflux Disease

Background/Aims

Increased salivary pepsin could indicate an increase in gastro-esophageal reflux, however, previous studies failed to demonstrate a correlation between salivary pepsin concentrations and 24-hour esophageal acid exposure. This study aims to detect the salivary pepsin and to evaluate the relationship between salivary pepsin concentrations and intercellular spaces (IS) in different gastroesophageal reflux disease phenotypes in patients.

Methods

A total of 45 patients and 11 healthy volunteers were included in this study. All subjects underwent upper gastrointestinal endoscopy, 24-hour ambulatory multichannel impedance-pH (MII-pH) monitoring, and salivary sampling at 3-time points during the 24-hour MII-pH monitoring. IS were measured by transmission electron microscopy, and salivary pepsin concentrations were determined by enzyme-linked immunosorbent assay.

Results

The IS measurements were greater in the esophagitis (EE), non-erosive reflux disease (NERD), and hypersensitive esophagus (HO) groups than in the functional heartburn (FH) and healthy volunteer groups, and significant differences were indicated. Patients with NERD and HO had higher average pepsin concentrations compared with FH patients. A weak correlation was determined between IS and salivary pepsin among patients with NERD (r = 0.669, P = 0.035).

Conclusions

We confirmed the presence of a higher level of salivary pepsin in patients with NERD than in patients with FH. Salivary pepsin concentrations correlated with severity of mucosal integrity impairment in the NERD group. We suggest that in patients with NERD, low levels of salivary pepsin can help identify patients with FH, in addition the higher the pepsin concentration, the more likely the severity of dilated IS.

The diagnostic value of pepsin detection in saliva for gastro-esophageal reflux disease: a preliminary study from China

Background

None of current diagnostic methods has been proven to be a reliable tool for gastro-esophageal reflux disease (GERD). Pepsin in saliva has been proposed as a promising diagnostic biomarker for gastro-esophageal reflux. We aimed to determine the diagnostic value of salivary pepsin detection for GERD.

Methods

Two hundred and fifty patients with symptoms suggestive of GERD and 35 asymptomatic healthy volunteers provided saliva on morning waking, after lunch and dinner for pepsin determination using the Peptest lateral flow device. All patients underwent 24-h multichannel intraluminal impedance pH (24-h MII-pH) monitoring and upper gastrointestinal endoscopy. Based on 24-h MII-pH and endoscopy study, patients were defined as GERD (abnormal MII-pH results and/or reflux esophagitis) and non-GERD otherwise.

Results

Patients with GERD had a higher prevalence of pepsin in saliva and higher pepsin concentration than patients with non-GERD and healthy controls (P < 0.001 for all). The pepsin test had a sensitivity of 73% and a specificity of 88.3% for diagnosing GERD using the optimal cut-off value of 76 ng/mL. Postprandial saliva samples collected when the symptoms occurred had a more powerful ability to identify GERD.

Conclusions

Salivary pepsin test had moderate diagnostic value for GERD. It may be a promising tool to replace the use of currently invasive tools with advantages of non-invasive, easy to perform and cost effective.

Trial registration

ChiCTR-DDD-16009506 (date of registration: October 20, 2016).

Is Pepsin a Reliable Marker of Laryngopharyngeal Reflux? A Systematic Review

Objective

Laryngopharyngeal reflux (LPR) is a common illness of otolaryngology visits. Over the past few years, pepsin has become a promising marker of LPR. The objective of the present research is to analyze the existing literature using pepsin as a diagnostic tool of LPR through a systematic review.

Data Sources

PubMed (Medline), Trip Database, Cochrane Library, EMBASE, SUMsearch, and Web of Science.

Review Methods

The outcome assessed was the presence of pepsin in LPR patients. We included articles in which pepsin was studied in LPR patients (clinically suspected or with confirmed diagnosis). Studies with no control group, comparison group, and/or a sample size lower than 20 patients were excluded.

Results

Twelve studies were included. All included studies, with the exception of 2, found statistically significant differences for pepsin in cases compared with healthy controls.

Conclusion

Pepsin might be a reliable marker in LPR patients, although questions remain about optimal timing, location, nature, and threshold values for pepsin testing. Future investigations are necessary to clarify the best method to use pepsin in the diagnostic process of LPR.

Pepsin as a Marker of Extraesophageal Reflux

Diagnosis of extraesophageal reflux (EER) currently relies on tools designed for diagnosis of gastroesophageal reflux. Such tools lack the sensitivity and reproducibility to detect the less frequent and mildly acidic reflux associated with upper airway disease. Pepsin has been posited to be a reliable biological marker of EER. Our aim was to present a comprehensive literature review of the use of pepsin as a diagnostic marker of EER. Two methods are typically used for detection of pepsin in the airways: enzymatic and immunologic. The limitations, advantages, and examples of use of each are discussed. Pepsin assay has been used to identify refluxate in trachea, lung, sinus, middle ear, combined sputum and saliva, and breath condensate. An immunologic pepsin assay of combined sputum and saliva was determined to be 100% sensitive and 89% specific for detection of EER (based on pH-metry), and an enzymatic test of nasal lavage fluid (100% sensitivity and 92.5% specificity) demonstrated an increased incidence of EER in patients with chronic rhinosinusitis. Pepsin assay identified tracheal pepsin to be an indicator of bronchopulmonary dysplasia and related mortality risk in ventilated preterm infants. Pepsin assay is a useful tool for correlation of reflux with airway disease and is a reliable diagnostic marker of EER.

Pepsin as a biomarker for laryngopharyngeal reflux in children with laryngomalacia

OBJECTIVES/HYPOTHESIS

Laryngomalacia is a common cause of newborn stridor. Laryngopharyngeal reflux (LPR) has been associated with laryngomalacia. Although pepsin, a component of LPR, has been associated with inflammatory diseases of the aerodigestive tract, its presence in the airways of laryngomalacia patients is unknown.

STUDY DESIGN

Prospective case-control study comparing patients under age 3 years with laryngomalacia to children without laryngomalacia.

METHODS

Children less than 3 years old undergoing supraglottoplasty for laryngomalacia or surgery unrelated to the airway, without a history of laryngomalacia, reflux, or respiratory disease, were offered enrollment. Supraglottic lavage samples (3 mL) were obtained from all subjects. Two-millimeter arytenoid biopsies were collected from laryngomalacia patients. Pepsin Western blot and enzyme-linked immunosorbent assay were performed.

RESULTS

Ten laryngomalacia and five control subjects were enrolled. Pepsin was detected in lavages of laryngomalacia patients (8/10) but absent in controls (0/5; P = .007). Pepsin was observed more frequently in lavages (8/10) than biopsies (4/10; P = .046) of laryngomalacia subjects. Higher median pepsin concentration was observed in laryngomalacia than control lavages (P = .025).

CONCLUSIONS

Pepsin in supraglottic specimens demonstrated an association with laryngomalacia, supporting a role for refluxed pepsin in laryngomalacia. These data corroborate previous work implicating pepsin in inflammatory diseases of the upper airways. Further studies are warranted to investigate the contribution of pepsin to the pathophysiology of laryngomalacia.

LEVEL OF EVIDENCE

3b. Laryngoscope, 127:2413-2417, 2017.

Pepsin in saliva as a biomarker for oropharyngeal reflux compared with 24-hour esophageal impedance/pH monitoring in pediatric patients

BACKGROUND

Pepsin in saliva is a proposed biomarker for oropharyngeal reflux. Pepsin may be prevalent in saliva from subjects with gastro-esophageal reflux and may correlate with proximal reflux by intraluminal impedance/pH monitoring (MII/pH).

METHODS

Patients (3 days to 17.6 years, n=90) undergoing 24-hour MII/pH monitoring and asymptomatic controls (2 months to 13.7 years, n=43) were included. Salivary pepsin was determined using a pepsin enzyme-linked immunosorbent assay. Eight saliva samples were collected from patients undergoing 24-hr MII/pH: (i) before catheter placement, (ii) before and 30 minutes after each of three meals, and (iii) upon awakening. One sample was collected from each control.

KEY RESULTS

In MII/pH subjects, 85.6% (77/90) had at least one pepsin-positive sample compared with 9.3% (4/43) in controls. The range of pepsin observed in individual subjects varied widely over 24 hours. The average pepsin concentration in all samples obtained within 2 hours following the most recent reflux event was 30.7±135 ng/mL, decreasing to 16.5±39.1 ng/mL in samples collected more than 2 hours later. The frequency of pepsin-positive samples correlated significantly with symptom index (r_S =0.332, P=.0014), proximal (r_S =0.340, P=.0010), and distal (r_S =0.272, P=.0095) MII events.

CONCLUSIONS & INFERENCES

Concentration of salivary pepsin may not be an accurate measure of severity of reflux because of the wide range observed in individuals over 24 hours. Saliva samples must be obtained soon after a reflux event. Defining a regimen for optimal saliva collection may help to achieve the goal of using salivary pepsin as a biomarker for oropharyngeal reflux.

CLINICAL TRIAL REGISTRY

NCT01091805.

Salivary Pepsin Lacks Sensitivity as a Diagnostic Tool to Evaluate Extraesophageal Reflux Disease

OBJECTIVES

To determine the sensitivity of salivary pepsin compared with multichannel intraluminal impedance with pH testing (pH-MII), endoscopy, and gastroesophageal reflux disease (GERD) questionnaires.

STUDY DESIGN

We prospectively recruited 50 children from Boston Children's Hospital who were undergoing pH-MII to evaluate for GERD. The patients completed 24-hour pH-MII testing, completed symptom and quality of life questionnaires, and provided a saliva specimen that was analyzed using the PepTest lateral flow test. A subset of patients also underwent bronchoscopy and esophagogastroduodenoscopy. Receiver operating characteristic curve analyses were performed to determine the sensitivity of salivary pepsin compared with each reference standard.

RESULTS

Twenty-one of the 50 patients (42%) were salivary pepsin-positive, with a median salivary pepsin concentration of 10 ng/mL (IQR, 10-55 ng/mL). There was no significant difference in the distributions of acid, nonacid, total reflux episodes, full column reflux, or any other reflux variable in patients who were pepsin-positive compared with those who were pepsin-negative (P > .50). There was no significant correlation between the number of reflux episodes and pepsin concentration (P > .10). There was no positive relationship between salivary pepsin positivity, any extraesophageal symptoms or quality of life scores, or inflammation on bronchoscopy or esophagogastroduodenoscopy (P > .30).

CONCLUSION

Salivary pepsin measurement has a low sensitivity for predicting pathological gastroesophageal reflux in children.