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

Biomarkers of Airway Disease, Barrett's and Underdiagnosed Reflux Noninvasively (BAD-BURN): a Case-Control Observational Study Protocol

BACKGROUND

Particulate matter exposure (PM) is a cause of aerodigestive disease globally. The destruction of the World Trade Center (WTC) exposed fifirst responders and inhabitants of New York City to WTC-PM and caused obstructive airways disease (OAD), gastroesophageal Refux disease (GERD) and Barrett's Esophagus (BE). GERD not only diminishes health-related quality of life but also gives rise to complications that extend beyond the scope of BE. GERD can incite or exacerbate allergies, sinusitis, bronchitis, and asthma. Disease features of the aerodigestive axis can overlap, often necessitating more invasive diagnostic testing and treatment modalities. This presents a need to develop novel non-invasive biomarkers of GERD, BE, airway hyperreactivity (AHR), treatment efficacy, and severity of symptoms.

METHODS

Our observational case-cohort study will leverage the longitudinally phenotyped Fire Department of New York (FDNY)-WTC exposed cohort to identify Biomarkers of Airway Disease, Barrett's and Underdiagnosed Refux Noninvasively (BAD-BURN). Our study population consists of n = 4,192 individuals from which we have randomly selected a sub-cohort control group (n = 837). We will then recruit subgroups of i. AHR only ii. GERD only iii. BE iv. GERD/BE and AHR overlap or v. No GERD or AHR, from the sub-cohort control group. We will then phenotype and examine non-invasive biomarkers of these subgroups to identify under-diagnosis and/or treatment efficacy. The findings may further contribute to the development of future biologically plausible therapies, ultimately enhance patient care and quality of life.

DISCUSSION

Although many studies have suggested interdependence between airway and digestive diseases, the causative factors and specific mechanisms remain unclear. The detection of the disease is further complicated by the invasiveness of conventional GERD diagnosis procedures and the limited availability of disease-specific biomarkers. The management of Refux is important, as it directly increases risk of cancer and negatively impacts quality of life. Therefore, it is vital to develop novel noninvasive disease markers that can effectively phenotype, facilitate early diagnosis of premalignant disease and identify potential therapeutic targets to improve patient care.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05216133; January 18, 2022.

Latin American consensus on diagnosis of gastroesophageal reflux disease

BACKGROUND

Diagnosing gastroesophageal reflux disease (GERD) can be challenging given varying symptom presentations, and complex multifactorial pathophysiology. The gold standard for GERD diagnosis is esophageal acid exposure time (AET) measured by pH-metry. A variety of additional diagnostic tools are available. The goal of this consensus was to assess the individual merits of GERD diagnostic tools based on current evidence, and provide consensus recommendations following discussion and voting by experts.

METHODS

This consensus was developed by 15 experts from nine countries, based on a systematic search of the literature, using GRADE (grading of recommendations, assessment, development and evaluation) methodology to assess the quality and strength of the evidence, and provide recommendations regarding the diagnostic utility of different GERD diagnosis tools, using AET as the reference standard.

KEY RESULTS

A proton pump inhibitor (PPI) trial is appropriate for patients with heartburn and no alarm symptoms, but nor for patients with regurgitation, chest pain, or extraesophageal presentations. Severe erosive esophagitis and abnormal reflux monitoring off PPI are clearly indicative of GERD. Esophagram, esophageal biopsies, laryngoscopy, and pharyngeal pH monitoring are not recommended to diagnose GERD. Patients with PPI-refractory symptoms and normal endoscopy require reflux monitoring by pH or pH-impedance to confirm or exclude GERD, and identify treatment failure mechanisms. GERD confounders need to be considered in some patients, pH-impedance can identify supragrastric belching, impedance-manometry can diagnose rumination.

CONCLUSIONS

Erosive esophagitis on endoscopy and abnormal pH or pH-impedance monitoring are the most appropriate methods to establish a diagnosis of GERD. Other tools may add useful complementary information.

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.

Threshold level of Peptest in diagnosing gastroesophageal reflux disease with extraesophageal symptoms: Evidence from Vietnam

Background and Aim

We aimed to evaluate the application of Peptest, a novel technique to detect pepsin in the saliva, and identify its threshold level for the diagnosis of gastroesophageal reflux disease (GERD) with extraesophageal symptoms.

Methods

A cross-sectional study was conducted in two groups: patients with extraesophageal GERD symptoms (symptomatic group divided into GERD and non-GERD groups according to 24-h esophageal pH-impedance monitoring [pH-I] results) and healthy controls. For the symptomatic group, endoscopy, pH 24 h, high-resolution manometry (HRM), and salivary Peptest were performed. For the healthy control group, only Peptest was done. The accuracy of Peptest was compared with that of pH-I by the Lyon consensus criteria.

Results

Chronic laryngitis was the most frequent extraesophageal symptom. On saliva testing, the GERD group had a higher prevalence of positive samples and pepsin concentration than the control group. Between GERD and non-GERD groups, the optimal threshold level was 31.2 ng/mL, with a sensitivity of 86.7% and specificity of 27.5%. The optimal threshold level was 31.4 ng/mL to differentiate GERD from healthy controls, with a sensitivity of 86.7% and specificity of 66.0%. Age, number of total refluxes, DeMeester score, post-reflux swallow-induced peristaltic wave (PSPW) index, and mean nocturnal baseline impedence (MNBI) were associated with pepsin concentration. Regarding HRM metrics, there was no significant difference of pepsin concentration between low/normal upper esophageal sphincter (UES) resting pressure, low/normal lower esophageal sphincter (LES) resting pressure, low/normal 4-s integrated relaxation pressure (IRP4s), and hypomotility/normal motility.

Conclusion

Patients with extraesophageal symptoms had a higher prevalence of positive Peptest. The optimum threshold level of 31.4 ng/mL had high sensitivity and moderate specificity to differentiate between patients with GERD and healthy controls.

Clinical relevance of salivary pepsin detection in diagnosing gastroesophageal reflux disease subtypes

Background

Gastroesophageal reflux disease (GERD) is heterogeneous with a varied symptom spectrum and reflux profiles. Its definite diagnosis often requires invasive tools including endoscopy or reflux monitoring. The aim of this study was to investigate the clinical relevance of salivary pepsin detection as a non-invasive screening tool to diagnose GERD of different subtypes.

Methods

A total of 77 patients with suspected GERD symptoms and 12 asymptomatic controls were analysed. All participants performed symptom evaluation, upper endoscopy, esophageal manometry, and 24-hour multichannel intraluminal impedance-dual pH probe monitoring. Saliva was self-collected across three different time points: at early fasting, postprandially, and at symptom occurrence. Salivary pepsin levels were measured via Peptest. The optimal threshold of salivary pepsin for diagnosing distal or proximal reflux was determined according to a receiver-operating characteristic curve.

Results

The average salivary pepsin concentration of suspected GERD patients was significantly higher than that of controls (100.63 [68.46, 141.38] vs 67.90 [31.60, 115.06] ng/mL, P = 0.044), although no difference was found among patients with different symptom spectrums. The distal reflux group had a higher average pepsin concentration than non-reflux patients (170.54 [106.31, 262.76] vs 91.13 [63.35, 127.63] ng/mL, P = 0.043), while no difference was observed between the distal reflux group and the proximal reflux group. The optimal cut-off value of salivary pepsin concentration for diagnosing pathological distal reflux was 157.10 ng/mL, which was higher than that for diagnosing pathological proximal reflux (122.65 ng/mL). The salivary pepsin concentration was significantly correlated with distal and proximal reflux parameters.

Conclusions

Salivary pepsin measurement can help in identifying true GERD with pathological distal reflux or proximal reflux, regardless of different symptom spectrums. A higher threshold should be applied for diagnosing distal reflux than for proximal reflux.

The clinical application value of salivary pepsin in the diagnosis of gastroesophageal reflux diseases

BACKGROUND

Peptest is a noninvasive and convenient diagnostic kit for gastroesophageal reflux disease (GERD). We aimed to explore the application value of Peptest in the diagnosis of GERD.

METHODS

Patients suspected of GERD all completed 24 h pH-impedance monitoring (24 h MII-pH) and then took proton pump inhibitor (PPI) 2 weeks. The postprandial, post-symptom and random salivary samples were taken. Receiver operating characteristic analysis was used to identify the best cutoff value of Peptest, to differentiate GERD patients from non-GERD patients and the optimal sampling time of Peptest was analyzed. Reflux characteristics and esophageal motility between Peptest (+) group and Peptest (-) group were compared in negative 24 h MII-pH patients. Peptest concentration were compared among non-reflux, distal reflux, and proximal reflux groups according to 24 h MII-pH curve.

RESULTS

The area under the curve of post-symptom Peptest was highest in three time points and the diagnostic specificity was 81.0% and sensitivity was 53.3% with the diagnostic value of 86 ng/mL. Compared with negative Peptest group, distal mean nocturnal baseline impedance was significantly lower, gastroesophageal junction contractile integral was substantially lower in positive Peptest group in negative 24 h MII-pH patients. The concentration of post-symptom and postprandial Peptest increased gradually in the non-reflux, distal reflux, and proximal reflux groups.

CONCLUSIONS & INFERENCES

Peptest has a relatively low diagnostic value for GERD. Post-symptom Peptset is the best sampling time with the optimal value of 86 ng/mL and may have auxiliary diagnostic value for negative 24 h MII-pH patients. Peptest may assist 24 h MII-pH in monitoring proximal reflux.

Saliva as Biomarker for Oral and Chronic Degenerative Non-Communicable Diseases

Saliva is a very complex fluid and it is essential to maintain several physiological processes and functions, including oral health, taste, digestion and immunological defenses. Saliva composition and the oral microbiome can be influenced by several factors, like diet and smoking habits, and their alteration can represent an important access point for pathogens and, thus, for systemic illness onset. In this review, we explore the potentiality of saliva as a new tool for the early detection of some pathological conditions, such as oral diseases, chronic degenerative non-communicable diseases, among these chronic kidney disease (CKD). We also examined the possible correlation between oral and systemic diseases and oral and gut microbiota dysbiosis. In particular, we deeply analyzed the relationship between oral diseases and CKD. In this context, some salivary parameters can represent a new device to detect either oral or systemic pathologies. Moreover, the positive modulation of oral and gut microbiota induced by prebiotics, postbiotics, or symbiotics could represent a new possible adjuvant therapy in the clinical management of oral diseases and CKD.

Pepsin in saliva for the diagnosis of erosive esophagitis post-sleeve gastrectomy: a prospective observational study

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) has become the preferred bariatric procedure in many countries. However, new onset erosive esophagitis (EE) is a major shortcoming. Current recommendation is esophago-gastro-duodenoscopy (EGD) should be performed routinely at 1 year and subsequently every 2-3 years to enable the early detection of Barrett's or esophageal adenocarcinoma. This would put significant strains on resources and costs of bariatric program. Our study assesses the association between and diagnostic value of salivary pepsin concentration and endoscopically proven EE in post-LSG patients as a surrogate for EGD.

METHODS

Twenty patients on routine post-LSG endoscopy between June and September 2022 were recruited for this correlational pilot study. Under supervision, fasting and post-prandial saliva sample was collected and analyzed by Peptest lateral flow device. EGD examinations were performed, and patients completed a validated 25-item QoLRAD questionnaire.

RESULTS

We found a significant correlation between positive endoscopy findings of EE and salivary pepsin concentrations. The normal group had a lower mean fasting pepsin level (13.13 ng/mL ± 18.97) versus the EE-group (90.55 ng/mL ± 81.28, p = 0.009) and lower mean post-prandial pepsin level (30.50 ng/mL ± 57.72) versus the EE-group (135.09 ng/mL ± 130.17, p = 0.02). The predictive probabilities from the binary regression of fasting and post-prandial pepsin concentrations yield AUC of 0.955 ± 0.044 (95% CI 0.868 to 1.000, p < 0.001).

CONCLUSION

Our study distinctively identified salivary pepsin to have excellent sensitivity and negative predictive value in EE, potentially useful to preclude the need for post-LSG EGD in asymptomatic patients with low salivary pepsin.

Diagnostic thresholds and optimal collection protocol of salivary pepsin for gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is primarily diagnosed based on symptoms and response to a proton-pump inhibitor (PPI) trial. Gold standard testing requires an invasive endoscopic procedure, often with ambulatory pH monitoring. Salivary pepsin is a potential noninvasive modality for GERD diagnosis. This study aimed to assess diagnostic performance of salivary pepsin thresholds for GERD and determine optimal collection protocol of saliva in an external validation cohort. Over 10 months, adults with symptoms of GERD undergoing esophagogastroduodenoscopy with wireless pH-monitoring off PPI were enrolled. Saliva was self-collected by participants over 4 days across three different time points: fasting ante meridiem (AM), post-prandial, and bedtime (PM). Pepsin levels were calculated via Peptest. Pepsin variability and agreement were determined using linear mixed effects models and intraclass correlation. Validation of diagnostic threshold and performance characteristics were evaluated by receiver-operator curve analysis. Twenty participants enrolled in the study; 50% with physiologic acid exposure (acid exposure time < 4% no GERD) and 50% with elevated acid exposure (GERD). Mean pepsin concentrations were significantly lower in the AM (22.6 ± 25.2 ng/mL) compared to post-prandial (44.5 ± 36.7 ng/mL) and PM (55.4 ± 47.0 ng/mL). Agreement between pepsin concentrations across 3 days was substantial for AM samples (kappa 0.61), with lower agreement for post-prandial and PM samples. A single AM pepsin concentration of 25 ng/mL was 67% accurate for GERD with 56% sensitivity and 78% specificity. This validation study highlights fair accuracy and performance characteristics of a single fasting AM salivary pepsin concentration for the diagnosis of GERD.

Evaluation of Salivary Pepsin Levels and Dental Erosion in Patients With Gastroesophageal Reflux Disease

Background Gastroesophageal reflux disease (GERD) is a common gastrointestinal condition affecting many individuals worldwide. GERD is characterized by esophageal symptoms and may contribute to various extraesophageal symptoms, including dental erosion (DE). This study aimed to estimate the levels of pepsin in the saliva of GERD patients to evaluate and compare the activity of pepsin between the GERD and healthy groups and investigate the prevalence of DE in the GERD group. Methodology In this case-control study, 40 patients with GERD, diagnosed with an endoscope, and 35 healthy subjects were included. Patients and healthy individuals were subjected to the GERD questionnaire (GerdQ). A dental assessment was performed using the Basic Erosive Wear Examination (BEWE). A total score of the BEWE risk level was obtained by summing the scores obtained in each sextant (no risk = ≤2, low risk = 3-8, medium risk = 9-13, and high risk = >13). Five milliliters of unstimulated saliva were collected in a sterile tube. The salivary pepsin levels examined using the enzyme-linked immunosorbent assay were recorded for both groups. Results DE was significantly more frequent in GERD patients compared to healthy subjects. Overall, 32 (80%) GERD patients and 11 (31.4%) healthy individuals had DE risk. The mean salivary pepsin was 43.60 ± 10.61 ng/mL in the GERD group and 20.60 ± 9.27 ng/mL in the healthy group. A statistically significant difference was found in pepsin levels between the two groups (p < 0.001). Conclusions The study concluded that GERD patients had a higher prevalence of DE than healthy individuals. Our findings suggest that elevated salivary pepsin levels and their role as a factor responsible for DE need further evaluation to understand the mechanisms of pepsin-mediated damage leading to DE.

Noninvasive, MultiOmic, and Multicompartmental Biomarkers of Reflux Disease: A Systematic Review

BACKGROUND AND AIMS

Gastroesophageal reflux disease (GERD) is a prevalent gastrointestinal disorder that may complicate conditions such as obstructive airway disease. Our group has identified predictive biomarkers of GERD in particulate exposed first responders with obstructive airway disease. In addition, GERD diagnosis and treatment is costly and invasive. In light of these clinical concerns, we aimed to systematically review studies identifying noninvasive, multiOmic, and multicompartmental biomarkers of GERD.

METHODS

A systematic review of PubMed and Embase was performed using keywords focusing on reflux disease and biomarkers and registered with PROSPERO. We included original human studies in English, articles focusing on noninvasive biomarkers of GERD published after December 31, 2009. GERD subtypes (non-erosive reflux disease and erosive esophagitis) and related conditions (Barrett's Esophagus [BE] and Esophageal Adenocarcinoma). Predictive measures were synthesized and risk of bias assessed (Newcastle-Ottawa Scale).

RESULTS

Initial search identified n = 238 studies andn 13 articles remained after applying inclusion/exclusion criteria. Salivary pepsin was the most studied biomarker with significant sensitivity and specificity for GERD. Serum assessment showed elevated levels of Tumor Necrosis Factor-alpha in both GERD and Barrett's. Exhaled breath volatile sulfur compounds and acetic acid were associated with GERD. Oral Microbiome: Models with Lautropia, Streptococcus, and Bacteroidetes showed the greatest discrimination between BE and controls vs Lautropia; ROCAUC 0.94 (95% confidence interval; 0.85-1.00).

CONCLUSION

Prior studies identified significant multiOmic, multicompartmental noninvasive biomarker risks for GERD and BE. However, studies have a high risk of bias and the reliability and accuracy of the biomarkers identified are greatly limited, which further highlights the need to discover and validate clinically relevant noninvasive biomarkers of GERD.

Salivary biomarkers and esophageal disorders

Saliva is a complex physiologic fluid that contains an abundance of biological analytes, or biomarkers. Recent research has shown that these biomarkers may be able to convey the physiologic health of a person. Work has been done linking derangements in these salivary biomarkers to a wide variety of pathologic disorders ranging from oncologic diseases to atopic conditions. The specific area of interest for this review paper is esophageal disorders. Particularly because the diagnosis and management of esophageal disorders often includes invasive testing such as esophagogastroduodenoscopy, prolonged pH monitoring, and biopsy. The aim of this review will be to explore salivary biomarkers (pepsin, bile, epidermal growth factor, and micro-RNA) that are being studied as they relate specifically to esophageal disorders. Finally, it will explore the benefits of salivary testing and identify areas of possible future research.

Gastroesophageal reflux disease and salivary pepsin in patients with heterotopic gastric mucosa in the upper esophagus

BACKGROUND

Heterotopic gastric mucosa in the upper esophagus (HGMUE) is reported to be related to gastroesophageal reflux disease (GERD). This study investigated the prevalence of GERD and the use of salivary pepsin to diagnose gastroesophageal reflux, especially proximal reflux, in HGMUE patients.

METHODS

One hundred and fifty-three HGMUE patients and 50 healthy volunteers were studied. All subjects took a reflux symptom index questionnaire (RSI); underwent endoscopy, barium esophagogram, high-resolution manometry (HRM), and 24-hour multichannel intraluminal impedance-pH-metry (MII-pH); and salivary pepsin test.

RESULTS

Ninety-five (62.1%) HGMUE patients but no control subjects were diagnosed with GERD. The salivary pepsin concentration, RSI score, DeMeester score, acid exposure time (AET), total reflux episodes, proximal acidic reflux episodes, and proximal weakly acidic reflux episodes were significantly higher in the HGMUE group than in the control group (P < 0.05). The salivary pepsin test showed a sensitivity of 85.9% and specificity of 56.9% for diagnosing GERD using the optimal cut-off value of 75 ng/mL. One hundred and seven (69.9%) and 46 (30.1%) HGMUE patients were categorized as pepsin (+) and pepsin (-), respectively when 75 ng/mL was used as a cut-off value. Male sex, RSI, AET, and proximal acid reflux episodes were positive predictive factors for the occurrence of pepsin (+) in HGMUE patients.

CONCLUSIONS

GERD, especially GERD with proximal acid reflux and related symptoms, was common in HGMUE patients. The salivary pepsin test could be an additional useful test for testing reflux in HGMUE patients, but it will not replace the MII-pH.

Rapid and Simple Analysis of the Human Pepsin Secondary Structure Using a Portable Raman Spectrometer

Human pepsin is a digestive protease that plays an important role in the human digestive system. The secondary structure of human pepsin determines its bioactivity. Therefore, an in-depth understanding of human pepsin secondary structure changes is particularly important for the further improvement of the efficiency of human pepsin biological function. However, the complexity and diversity of the human pepsin secondary structure make its analysis difficult. Herein, a convenient method has been developed to quickly detect the secondary structure of human pepsin using a portable Raman spectrometer. According to the change of surface-enhanced Raman spectroscopy (SERS) signal intensity and activity of human pepsin at different pH values, we analyze the change of the human pepsin secondary structure. The results show that the content of the β-sheet gradually increased with the increase in the pH in the active range, which is in good agreement with circular dichroism (CD) measurements. The change of the secondary structure improves the sensitivity of human pepsin SERS detection. Meanwhile, human pepsin is a commonly used disease marker for the noninvasive diagnosis of gastroesophageal reflux disease (GERD); the detection limit of human pepsin we obtained is 2 μg/mL by the abovementioned method. The real clinical detection scenario is also simulated by spiking pepsin solution in saliva, and the standard recovery rate is 80.7-92.3%. These results show the great prospect of our method in studying the protein secondary structure and furthermore promote the application of SERS in clinical diagnosis.

Salivary peptest for laryngopharyngeal reflux and gastroesophageal reflux disease: A systemic review and meta-analysis

BACKGROUND

A rapid lateral flow test (Peptest) to detect pepsin in saliva/sputum has been considered as a valuable method for diagnosing laryngopharyngeal reflux (LPR) and gastroesophageal reflux disease (GERD). The aim of this meta-analysis is to analyze the utility of Peptest for diagnosis of LPR and GERD.

METHODS

PubMed, EMBASE, and the Cochran Library (from January 1980 to 26 January 2020) were searched for pepsin in saliva for LPR/GERD diagnosis. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve data were summarized to examine the accuracy.

RESULTS

A total of 16 articles that included 2401 patients and 897 controls were analyzed. The pooled sensitivity and specificity for the diagnosis of GERD/LPR with Peptest were 62% (95% confidence interval [CI] 49%-73%) and 74% (95% CI 50%-90%), respectively. The summarized diagnostic odds ratio and area under the curve were 5.0 (95% CI 2-19) and 0.70 (95% CI 0.66-0.74), respectively.

CONCLUSION

Peptest shows moderate diagnostic value for LPR and GERD. More studies with standard protocols should be done to verify its usefulness.

The Role of Salivary Pepsin in the Diagnosis of Gastroesophageal Reflux Disease (GERD) Evaluated Using High-Resolution Manometry and 24-Hour Multichannel Intraluminal Impedance-pH Monitoring

BACKGROUND The Lyon Consensus classification confirms or rules out gastroesophageal reflux disease (GERD). The refractory symptoms of patients with GERD taking proton pump inhibitors (PPIs) are challenging in clinical practice. Salivary pepsin concentration was proposed as a diagnostic biomarker for GERD. We aimed to determine the diagnostic value of salivary pepsin concentration for patients with conclusive GERD, based on the Lyon classification, and the correlation of salivary pepsin concentration with parameters of high-resolution manometry and 24-h multichannel intraluminal impedance-pH in patients with PPI-refractory symptoms. MATERIAL AND METHODS Saliva samples obtained from 130 patients who were suspicious for GERD and had PPI-refractory symptoms were used for pepsin determination using the enzyme-linked immunosorbent assay. All patients underwent upper gastrointestinal endoscopy, high-resolution manometry, 24-h multichannel intraluminal impedance, and pH recording and were classified as conclusive GERD, inconclusive GERD, and evidence against GERD groups according to Lyon classification. RESULTS Salivary pepsin concentration was 8.2 ng/mL (3.8-17.8 ng/mL), 4.0 ng/mL (2.3-6.1 ng/mL), and 2.4 ng/mL (2.2-3.1 ng/mL) in conclusive GERD, inconclusive GERD, and evidence against GERD groups, respectively (P<0.001), and had a negative correlation with distal mean nocturnal baseline impedance and positive correlations with acid exposure time, total number of reflux events, and esophagogastric junction type. The area under the ROC curve of salivary pepsin for conclusive GERD was 0.76 (0.68-0.84), with a sensitivity of 76.36% and a specificity of 63.41% for conclusive GERD diagnosis at a cut-off value of 4.21 ng/mL. CONCLUSIONS Salivary pepsin test had moderate diagnostic value for conclusive GERD by Lyon classification in patients with PPI-refractory symptoms.

Efficacy evaluation of pepsin in laparoscopic antireflux surgery for gastroesophageal reflux disease

BACKGROUND

The false positive rate of the PPI test for the diagnosis of typical symptoms of gastroesophageal reflux disease (GERD) is extremely high.

OBJECTIVE

This study aims to investigate the effect of the pepsin test on GERD and laparoscopy-assisted anti-reflux surgery for GERD.

METHODS

A total of 30 GERD patients were enrolled into this study, and the pre-diagnosis of GERD was determined by symptom evaluation, impedance-pH examination, gastroscopy and pepsin test. All patients underwent surgery.

RESULTS

Among the 30 GERD patients, 18 patients were male and 12 were female, and their average age was 58.2 + 12.6 years old. The patients were treated with laparoscopic fundoplication and hiatus hernia repair after preoperative assessment. A total of 28 patients were followed up, one patient developed recurrent symptoms, and one patient developed postoperative dysphagia and received non-operative treatment. Furthermore, the symptom scores were significantly lower at postoperative pepsin detection when compared to the scores before the operation (pepsin: preoperative: 148.8 ± 82.6, postoperative: 30.7 ± 24.6; t= 4.848, P= 0.000).

CONCLUSIONS

Laparoscopic fundoplication and hiatus hernia repair may effectively control the symptoms of GERD. Furthermore, the detection of pepsin is non-invasive and easy to operate.

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.

Biochemical analysis of oral fluids for disease detection

The field of diagnostics using invasive blood testing represents the majority of diagnostic tests used as part of routine health monitoring. The relatively recent introduction of salivary diagnostics has lead to a major paradigm shift in diagnostic analyses. Additionally, in this era of big data, oral fluid testing has shown promising outcomes in a number of fields, particularly the areas of genomics, microbiomics, proteomics, metabolomics, and transcriptomics. Despite the analytical challenges involved in the interpretation of large datasets generated from biochemical studies involving bodily fluids, including saliva, many studies have identified novel oral biomarkers for diagnosing oral and systemic diseases. In this regard, oral biofluids, including saliva, gingival crevicular fluid (GCF), peri-implant crevicular fluid (PICF), dentinal tubular fluid (DTF), are now attracting increasing attention due to their important attributes, such as noninvasive sampling, easy handling, low cost, and more accurate diagnosis of oral diseases. Recently, the utilization of salivary diagnostics to evaluate systemic diseases and monitor general health has increased in popularity among clinicians. Saliva contains a wide range of protein, DNA and RNA biomarkers, which assist in the diagnosis of multiple diseases and conditions, including cancer, cardiovascular diseases (CVD), auto-immune and degenerative diseases, respiratory infections, oral diseases, and microbial (viral, bacterial and fungal) diseases. Moreover, due to its noninvasive nature and ease-of-adoption by children, it is now being used in mass screening programs, oral health-related studies and clinical trials in support of the development of therapeutic agents. The recent advent of highly sensitive technologies, such as next-generation sequencing, mass spectrometry, highly sensitives ELISAs, and homogeneous immunoassays, suggests that even small quantities of salivary biomarkers are able to be assayed accurately, providing opportunities for the development of many future diagnostic applications (including emerging technologies, such as point-of-care and rapid molecular technologies). The present article explores the omics and biochemical compositions of various oral biofluids with important value in diagnostics and monitoring.

Clinical utility of salivary pepsin measurement in patients with proton pump inhibitor-refractory gastroesophageal reflux disease symptoms: a prospective comparative study

BACKGROUND

Salivary pepsin measurement has been reported to be useful for diagnosing gastroesophageal reflux disease (GERD). This study aimed to clarify the usefulness of salivary pepsin measurement in patients with proton pump inhibitor (PPI)-refractory GERD symptoms without erosive esophagitis.

METHODS

One hundred and two patients were included. Over seven days after terminating PPI treatment, all patients underwent a 24-h pH-impedance test and salivary pepsin measurement. In patients whose main symptoms included laryngopharyngeal symptoms, a hypopharyngeal multichannel intraluminal impedance (HMII) test was performed, whereas in other patients, a conventional combined multichannel intraluminal impedance-pH (MII-pH) test was performed. In the HMII tests, patients were divided into abnormal proximal exposure (APE) and non-APE groups. Salivary pepsin concentrations were compared according to acid exposure time (AET) values and were also compared between the APE and non-APE groups.

RESULTS

The median salivary pepsin concentration in patients with AET > 6% was significantly higher than that in patients with AET ≤ 6% (345.0 [170.0-469.3] ng/mL vs. 120.0 [97.0-290.1] ng/mL, p < 0.01). The sensitivity, specificity, positive predictive value, and negative predictive value of a positive test (> 109 ng/mL) to diagnose patients with AET > 6% were 75.0%, 51.3%, 32.1%, and 86.9%, respectively. There was no significant difference between concentrations in the APE group and concentrations in the non-APE group.

CONCLUSIONS

In patients with PPI-refractory nonerosive reflux disease, salivary pepsin measurement may help diagnose patients who have conclusive evidence of reflux, whereas it is not adequate for identifying patients with APE.

Saliva as an alternative to blood in the determination of uremic state in adult patients with chronic kidney disease: a systematic review and meta-analysis

OBJECTIVES

To assess whether salivary urea and creatinine levels accurately reflect their serum levels in blood samples of adults to detect chronic kidney disease.

MATERIALS AND METHODS

A systematic review was conducted in eight electronic databases. The protocol was registered in PROSPERO. Only diagnostic test studies were included. The JBI critical appraisal tools assessed the risk of bias. A meta-analysis of proportions was performed. The GRADE tool assessed the quality of evidence and strength of recommendation across the studies included.

RESULTS

Eight studies met the eligibility criteria and were included. Six studies assessed salivary urea, and six studies assessed salivary creatinine. All studies presented moderate risk of bias. The meta-analysis depicted an overall sensitivity of 93.3% (95% CI = 88.6; 97.9) for salivary creatinine levels and 87.5% (95% CI = 83.2; 91.8) for salivary urea levels, while the overall specificity was 87.1% (95% CI = 82.8; 91.3) and 83.2% (95% CI = 65.0; 101.4) for salivary creatinine and urea levels, respectively. The overall accuracy of salivary creatinine was 5.2 percentage points higher compared with salivary urea levels (90.8% vs. 85.6%). According to the GRADE tool, the analysed outcomes were classified as having low to moderate level of certainty.

CONCLUSION

Compared with blood samples, salivary urea and creatinine levels presented high diagnostic values for chronic kidney disease screening, but should not be considered equivalent to levels obtained from blood at stages three, four, or five of the disease.

CLINICAL SIGNIFICANCE

Chronic kidney disease patients could receive a clinically significant benefit from replacing blood with saliva for potentially monitoring renal function. Saliva collection presents greater simplicity, comfort, safety, and lower collection cost.

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

Typical symptoms and not positive reflux-cough correlation predict cure of gastroesophageal reflux disease related chronic cough after laparoscopic fundoplication: a retrospective study

Background

The effect of laparoscopic fundoplication on reflux-related chronic cough is unpredictable, the aim of the study is to investigate the predictive effect of positive reflux-cough correlation on the resolution of reflux-related chronic cough after anti-reflux surgery.

Methods

A 5 years retrospective review was performed. Logistic regression analysis was used to determine the independent predictors on the cure of chronic cough.

Results

Seventy-nine patients were included in this study, among which chronic cough was cured in 47 (59.5%) and significantly improved in 10 (12.7%) patients. Present of typical symptoms (odds ratio = 6.435,95% confidence interval [CI] = 1.427–29.032, p = 0.015) and number of Reflux episodes (impedance) ≥73 (odds ratio = 0.306, 95% confidence interval [CI] = 0.107–0.874, p = 0.027) were significantly associated with the cure of chronic cough.

Conclusions

laparoscopic fundoplicaiton is effective for the management of reflux-related chronic cough, particularly with the present of typical symptoms.

Trial registration

(Trial registration number: ChiCTR1800016444; Trial registration date: June 01, 2018)

Validation in China of a non-invasive salivary pepsin biomarker containing two unique human pepsin monoclonal antibodies to diagnose gastroesophageal reflux disease

OBJECTIVES

Peptest is a new non-invasive reflux diagnostic test based on lateral flow technology that containing two highly specific human pepsin monoclonal antibodies for detecting pepsin, a biomarker for reflux disease. The primary aim of this multicenter clinical study was to validate the efficacy of Peptest in patients diagnosed with gastroesophageal reflux and healthy controls in China.

METHODS

Patients with suspected gastroesophageal reflux underwent an endoscopy and were classified into non-erosive reflux disease and erosive esophagitis subgroups. A healthy control group was also recruited. All participants were given a reflux disease questionnaire-patients scoring greater than 12 and controls scoring zero. All participants provided a postprandial saliva sample and most patients gave an additional post-symptom sample for pepsin analysis.

RESULTS

Altogether 1032 participants aged between 19 and 78 years were recruited. They consisted of 488 patients with non-erosive reflux disease, 221 with erosive esophagitis and 323 healthy controls. The number of postprandial and post-symptom samples analyzed totaled 1031 and 692, respectively. The results across all centers showed an overall pepsin-positive sensitivity of 85%, a specificity of 60%, a positive predictive value of 82%, a negative predictive value of 65% and a positive likelihood ratio of 2.12.

CONCLUSION

The sensitivity of Peptest was high, but the specificity achieved in some centers was low, resulting overall in only a moderate specificity. Further diagnostic investigative studies are warranted.

Letter: studies of salivary pepsin in patients with gastro-oesophageal reflux disease

Linked Content This article is linked to Race et al and Corfe et al papers. To view these articles, visit https://doi.org/10.1111/apt.15138 and https://doi.org/10.1111/apt.15225.

Studies of salivary pepsin in patients with gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease (GERD) is difficult to diagnose without invasive testing. Peptest (RD Biomed, Hull, UK) is a recently marketed diagnostic tool which aims to quantify salivary pepsin as a marker of reflux, providing a rapid alternative to invasive procedures.

AIM

To evaluate optimal timing for sampling, and to evaluate the accuracy of Peptest against an independent measure.

METHODS

Thirty diagnosed GERD patients (12 female, mean age 49 [range 20-72]) and 20 asymptomatic subjects (14 female, mean age 56 [range 21-56]) were subject to diurnal saliva sampling, with additional samples for 60 minutes following self-reported reflux symptoms and triggering of a proximal reflux alarm. Saliva samples were split and were analysed by both Peptest and ELISA with operators for each blinded to sample identity.

RESULTS

Salivary pepsin was detectable in most patients and most volunteers. Peptest scores were significantly lower for patients than controls (P < 0.005). ELISA scores showed no difference between patients and controls. There was no effect of diurnal sampling time (P = 0.75) or time after symptoms (P = 0.76) on Peptest readout. There was no correlation between Peptest and Pepsin ELISA (P = 0.55); Bland-Altman analysis suggested no agreement between the tests (P = 0.414). Receiver-operator curve suggests that neither Peptest (P = 0.3328) nor pepsin (P = 0.4476) is useful for predicting GERD.

CONCLUSION

Salivary pepsin is not a reliable tool for the diagnosis of GERD.

Pepsin in Saliva as a Diagnostic Marker for Gastroesophageal Reflux Disease: A Meta-Analysis

BACKGROUND Gastroesophageal reflux disease (GERD) is very common. Salivary pepsin detection has previously been considered as a method for GERD diagnosis. We performed a meta-analysis to investigate the utility of salivary pepsin assay as a diagnostic tool of GERD. MATERIAL AND METHODS PubMed, Web of Science, the Cochran Library, and EMBASE (from January 1980 to 23 October 2018) were searched for pepsin in saliva for GERD diagnosis. We summarized the retrieved specificity, sensitivity, negative likelihood ratio (NLR), positive likelihood ratio (PLR), diagnostic odds ratio (DOR), and receiver operating characteristic (ROC) curves data in the meta-analysis. RESULTS In final analysis, a total of 5 studies were included. The summary sensitivity, specificity, NLR, and PLR were 0.60 (95% CI 0.41-0.76), 0.71 (95% CI 0.51-0.86), 0.56 (95% CI 0.34-0.93), and 2.1 (95% CI 1.1-4.1), respectively. The pooled DOR was 4 (95% CI 1.0-11.0) and area under the ROC was 0.70 (95% CI 0.66-0.74). CONCLUSIONS The meta-analysis showed that pepsin in saliva has moderate diagnostic value for GERD, and is not as helpful as previously thought.

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.