Salivary Pepsin as an Intrinsic Marker for Diagnosis of Sub-types of Gastroesophageal Reflux Disease and Gastroesophageal Reflux Disease-related Disorders

Development of Highly Sensitive Fluorescent Sensors for Separation-Free Detection and Quantitation Systems of Pepsin Enzyme Applying a Structure-Guided Approach

Two fluorescent molecularly imprinted polymers (MIPs) were developed for pepsin enzyme utilising fluorescein and rhodamine b. The main difference between both dyes is the presence of two (diethylamino) groups in the structure of rhodamine b. Consequently, we wanted to investigate the effect of these functional groups on the selectivity and sensitivity of the resulting MIPs. Therefore, two silica-based MIPs for pepsin enzyme were developed using 3-aminopropyltriethoxysilane as a functional monomer and tetraethyl orthosilicate as a crosslinker to achieve a one-pot synthesis. Results of our study revealed that rhodamine b dyed MIPs (RMIPs) showed stronger binding, indicated by a higher binding capacity value of 256 mg g-1 compared to 217 mg g-1 for fluorescein dyed MIPs (FMIPs). Moreover, RMIPs showed superior sensitivity in the detection and quantitation of pepsin with a linear range from 0.28 to 42.85 µmol L-1 and a limit of detection (LOD) as low as 0.11 µmol L-1. In contrast, FMIPs covered a narrower range from 0.71 to 35.71 µmol L-1, and the LOD value reached 0.34 µmol L-1, which is three times less sensitive than RMIPs. Finally, the developed FMIPs and RMIPs were applied to a separation-free quantification system for pepsin in saliva samples without interference from any cross-reactors.

An impedimetric sensor based on molecularly imprinted nanoparticles for the determination of trypsin in artificial matrices - towards point-of-care diagnostics

A high-performance impedimetric sensing platform was designed to detect proteins by employing molecularly imprinted polymeric nanoparticles (nanoMIPs) as selective receptors. This was achieved via the combination of the nanoMIPs with a self-assembled thioctic acid (SAM-TA) monolayer onto screen-printed gold electrodes, providing stable covalent attachment of the selective binder to the transducer. Taguchi design has been modelled to achieve the optimal level of sensor fabrication parameters and to maximise the immobilisation of nanoMIPs and their response (e.g. the response of imprinted polymers compared with the non-imprinted control). The developed sensor was tested towards a range of concentrations of trypsin dissolved in ammonium acetate (pH = 6) and showed promising applicability in artificial saliva, with a recovery percentage between 103 and 107%.

A Non-Invasive Technique for Long-Term Monitoring of Gastroesophageal Reflux-A Pilot Study

Many people suffer from gastric or gastroesophageal reflux disorder (GERD) due to a malfunction of the cardia, the valve between the esophagus and the stomach. GERD is a syndrome caused by the ascent of gastric juices and bile from the stomach. This article proposes a non-invasive impedance measurement method and demonstrates the correlation between GERD and impedance variation between appropriately chosen points on the patient's chest. This method is presented as an alternative to the most widely accepted diagnostic techniques for reflux, such as pH-metry, pH-impedance measurement, and esophageal manometry, which are invasive because they use a probe that is inserted through a nostril and reaches down to the esophagus.

Association between salivary characteristics and tooth wear: A systematic review and meta-analysis

OBJECTIVE

Literature was systematically reviewed to identify salivary characteristics and their association with tooth wear.

DATA

A protocol was developed a priori (PROSPERO CRD42022338590). Established systematic review methods were used for screening, data extraction, and synthesis. Risk of bias and the certainty of evidence were assessed using the JBI tools and GRADE, respectively. Direct and indirect association between tooth wear and salivary components and characteristics were assessed.

SOURCES

MEDLINE, Embase, SCOPUS, Web of Science, CINAHL, and additional sources were searched.

STUDY SELECTION

Studies reporting salivary characteristics in patients with tooth wear or models thereof were included. Animal and in-vitro studies and case reports were excluded.

RESULTS

One-hundred eleven studies were included. Qualitative analyses showed a negative association between tooth wear and salivary pH and flow rate in many studies. The higher the study size the higher the chances that an association with pH and flow rate was found. Xerostomia, buffer capacity and salivary consistency/viscosity had also some degree of association with tooth wear in fewer studies. Associations with the 39 salivary components were scarcer. Random effects meta-analyses (7 studies) showed that pH levels in stimulated whole saliva were lower in patient with tooth wear compared to controls (-0.07 [-0.10 to -0.04]). However, there was not enough evidence to establish a quantitative association with flow rate. The general risk of bias was unclear and the certainty of evidence was low or very low. A large diversity of methodologies limited the inclusion of all studies in quantitative synthesis.

CONCLUSION

From all potential risk factors, stimulated whole saliva pH showed a negative association, both quantitatively and qualitatively with tooth wear, indicating potential usefulness of pH monitoring in these patients. Moreover, associations between flow rate and tooth wear were observed qualitatively. However, in both cases the risk of bias was mostly unclear, and the certainty of evidence was low. No causal associations could be observed.

CLINICAL SIGNIFICANCE

Tooth wear is a prevalent condition that may lead to functional or esthetic impairments and pain. Knowing the potential risk factors like salivary pH or flow rate and their dynamics could be relevant during tooth wear monitoring and to intervene accordingly, especially in conditions like gastroesophageal reflux disease.

A prospective study of extraesophageal reflux and potential microaspiration in patients hospitalized with COVID-19 in Jordan

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lung infection has represented a global challenge. Intriguingly, it has been shown that the alveolar lung epithelium expresses little Angiotensin Converting Enzyme receptor protein (ACE2), the entry receptor for SARS-CoV-2. Upper airway establishment of infection and translocation to the lung is well documented but other anatomical niches may be relevant to potentially serious lung infection. ACE2 is heavily expressed in the gastrointestinal tract and gastrointestinal symptoms support a clinical diagnosis of Coronavirus disease 2019 (COVID-19). This suggests a research question and the need to gather patient data exploring potential aerodigestive links in SARS-CoV-2 tranlocation and infection which may be relevant in the peripheral lung. This recognizes anatomical proximity and concepts of bi-directional movement between the Gastrointestinal and lung systems in normal physiology and disease. We have therefore explored the potential for gastro oesophageal reflux disease (GORD) micro aspiration and aeorodigestive pathophysiology in a novel prospective investigation of patients hospitalized with COVID-19.

METHODS

This is a prospective descriptive cohort study of 210 patients who were hospitalized with a confirmed diagnosis of COVID-19. The cohort was divided into three groups of patients based on symptom severity and radiological results. The Reflux Symptom Index (RSI) was used to evaluate the presence and severity of GOR. An RSI greater than 13 is considered to be abnormal. Patients' saliva samples were tested using enzyme-linked immunosorbent assay (ELISA) to determine the level of salivary pepsin among the cohort of patients.

RESULTS

A total of 210 patients with COVID-19 were enrolled in the study with 55.2% (116/210) classified as mildly ill, 31.9% (67/210) moderately ill and 12.9% (27/210) as severely ill. 34% (72/210) of the patients had an RSI score of over 13 and a median salivary pepsin value of 54 ± 29 ng/ml which suggested an incidence of extraesophageal reflux (EOR) in around a third of patients. The presence of respiratory comorbid conditions, an RSI score of over 13 and a salivary pepsin level of > 76ng/ml increased the risk of developing a more severe COVID-19 infection.

CONCLUSION

The study showed a high prevalence of EOR among the study cohort and provide the first prospective evidence suggesting the potential for aerodigestive pathophysiology including microaspiration in COVID-19 disease. We believe that the results of our study support the need for more extensive research.

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.

Multidimentional assessment of voice quality in patients with laryngopharyngeal reflux disease

<b><br>Introduction:</b> Gastroesophageal Reflux Disease (GERD) is a common disorder in world population. As a result of the regurgitation of acid content from the stomach to laryngopharynx and larynx, secondary damage of laryngeal mucosa occur, which is highly sensitive to hydrochloric acid, and morphological changes are observed. Symptomatology of laryngopharyngeal reflux is varied which makes differential diagnosis difficult.</br> <b><br>Aim:</b> The aim of the study was the assessment of voice quality, morphological changes in larynx as well as etiology of Laryngopharyngeal Reflux Disease.</br> <b><br>Material and method:</b> The severity of dysphonia was classified using perceptual and acoustic methods as well as RSI. Morphological control was performed using HSDI technique and RFS. Etiological factors were examined basing on barofunction of upper esophageal sphincter and 24-hour pH-metry of air exhaled expressed in Ryan score.</br> <b><br>Results:</b> In the majority of patients with Laryngopharyngeal Reflux, dysphonia was recognized, intensified especially in women (G3R2B0A0S3), which was confirmed in Yanagihara classification (type III) and parameters of acoustic analysis. Voice disorders were the most frequently the result of edema and congestion of interarytenoid area, aytenoids and vocal folds. Those symptoms were caused by the decrease of upper esophageal sphincter tension and acidity of exhaled air which was confirmed in 24-hour pHmetry.</br> <b><br>Conclusions:</b> It is important to educate physicians and patients about the possibilty of negative impact of reflux disease on the occurrence of voice quality disorders. Current diagnostic methods for dysphonia guarantee accurate recognition and therapeutic success improving the prognoses of patients with Laryngopharyngeal Reflux.</br>.

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.

Promising applications of human-derived saliva biomarker testing in clinical diagnostics

Saliva testing is a vital method for clinical applications, for its noninvasive features, richness in substances, and the huge amount. Due to its direct anatomical connection with oral, digestive, and endocrine systems, clinical usage of saliva testing for these diseases is promising. Furthermore, for other diseases that seeming to have no correlations with saliva, such as neurodegenerative diseases and psychological diseases, researchers also reckon saliva informative. Tremendous papers are being produced in this field. Updated summaries of recent literature give newcomers a shortcut to have a grasp of this topic. Here, we focused on recent research about saliva biomarkers that are derived from humans, not from other organisms. The review mostly addresses the proceedings from 2016 to 2022, to shed light on the promising usage of saliva testing in clinical diagnostics. We recap the recent advances following the category of different types of biomarkers, such as intracellular DNA, RNA, proteins and intercellular exosomes, cell-free DNA, to give a comprehensive impression of saliva biomarker testing.

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.

Using RSI and RFS scores to differentiate between reflux-related and other causes of chronic laryngitis

OBJECTIVE

To establish if the Reflux Symptom Index (RFI) and the Reflux Finding Score (RFC) can help establish the differential diagnosis in patients with distinct causes of chronic laryngopharyngitis.

METHODS

A group of 102 adult patients with chronic laryngopharyngitis (Group A - 37 patients with allergic rhinitis; Group B - 22 patients with Obstructive Sleep Apnea (OSA); Group C - 43 patients with Laryngopharyngeal Reflux (LPR)) were prospectively studied. Chronic laryngitis was diagnosed based on suggestive symptoms and videolaryngoscopic signs (RSI ≥ 13 and RFS ≥ 7). Allergies were confirmed by a positive serum RAST, OSA was diagnosed with a positive polysomnography, and LPR with a positive impedance-PH study. Discriminant function analysis was used to determine if the combination of RSI and RFS scores could differentiate between groups.

RESULTS

Patients with respiratory allergies and those with LPR showed similar and significantly higher RSI scores when compared to that of patients with OSA (p < 0.001); Patients with OSA and those with LPR showed similar and significantly higher RFS scores when compared to that of patients with Respiratory Allergies (OSA vs. Allergies p < 0.001; LPR vs. Allergies p < 0.002). The combination of both scores held a higher probability of diagnosing OSA (72.73%) and Allergies (64.86%) than diagnosing LPR (51.16%).

CONCLUSIONS

RSI and RFS are not specific for reflux laryngitis and are more likely to induce a false diagnosis if not used with diligence.

Usefulness of matrix metalloproteinase-7 in saliva as a diagnostic biomarker for laryngopharyngeal reflux disease

Several diagnostic methods are currently being used to diagnose LPRD (laryngopharyngeal reflux disease), but have the disadvantage of being invasive, subjective, or expensive. Our purpose in this study was to investigate the correlation between pepsin and MMP-7 (Matrix Metalloproteinase-7) in pharyngeal secretions of subjects according to RSI (Reflux Symptom Index) score to find out the diagnostic value of MMP-7. We recruited 173 subjects aged between 19 and 85 years who completed the RSI scale. All samples were taken after waking up, and the amount of the pepsin and MMP-7 in saliva were measured by means of an enzyme activity assay. There was a significant increase of pepsin and MMP-7 activity in the study group with an RSI score of 13 or higher. The sensitivity and specificity of MMP-7 for predicting the possibility of an RSI of 13 or more was higher than that of pepsin. When MMP-7 and pepsin were combined, this sensitivity and specificity increased. An enzyme assay of MMP-7 in saliva may be a noninvasive and easy technique for diagnosing LPRD.

The Impact of Laryngopharyngeal Reflux on Occurrence and Clinical Course of Recurrent Respiratory Papillomatosis

OBJECTIVES/HYPOTHESIS

Laryngopharyngeal reflux (LPR) has been proposed both as a trigger for recurrent respiratory papillomatosis (RRP) onset and as a factor favoring an aggressive clinical course.

STUDY DESIGN

In this prospective study, 106 participants were recruited within a period of 24 months at the Department of Otorhinolaryngology and Cervicofacial Surgery, University Medical Centre Ljubljana.

METHODS

This study compared a group of RRP patients (N = 36) with a group of LPR patients (N = 28) and a group of healthy participants (N = 42) based on Reflux Symptom Index (RSI), Reflux Finding Scores (RFS), and saliva analyses (pH, pepsin concentration, bile acid concentration, and pepsin enzymatic activity).

RESULTS

The RRP group compared to the LPR group showed a statistically significant difference only in RSI and RFS scores, while the RRP group compared to healthy controls showed significantly higher values in all tested parameters (RSI score, RFS, saliva pH, pepsin concentration, bile acids concentration, pepsin enzymatic activity).

CONCLUSIONS

LPR is common in RRP patients and significantly more prevalent compared to healthy controls. Our results show that saliva analyses are a better office-based tool than RSI questionnaires and RFS scores for diagnosing LPR in RRP patients.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 2021.

Diagnostic performance of salivary pepsin for gastroesophageal reflux disease

Uncertain diagnostic performance has limited clinical adoption of salivary pepsin, a noninvasive diagnostic tool for gastroesophageal reflux disease (GERD). This study aimed to assess diagnostic performance of salivary pepsin, and test validity of thresholds in an external cohort of patients with or without GERD. This two-phase prospective study conducted at two centers enrolled adult asymptomatic volunteers, patients with symptoms of GERD undergoing reflux monitoring, and patients with Barrett's esophagus (BE). Fasting saliva samples were processed for pepsin concentration using Peptest. Phase 1 compared pepsin concentration between No GERD (volunteers/functional heartburn) and GERD (erosive reflux disease/nonerosive reflux disease (NERD)/BE). Phase 2 tested validity of the diagnostic thresholds identified from Phase 1 among external functional heartburn and NERD cohorts. Of 243 enrolled subjects, 156 met inclusion criteria. Phase 1 (n = 114): Pepsin concentrations were significantly higher in GERD (n = 84) versus No GERD (n = 30) (73.8 ng/mL vs. 21.1 ng/mL; P < 0.001). Area under the curve for pepsin concentration was 0.74 (95% CI 0.65, 0.83). A salivary pepsin threshold of 24.9 ng/mL optimized the true negative rate and 100.0 ng/mL optimized the true positive rate. Phase 2 (n = 42): Pepsin concentrations were significantly higher in NERD (n = 22) versus Functional Heartburn (n = 20) (176.0 ng/mL vs. 53.3 ng/mL, P < 0.001). Applying Phase 1 thresholds in this external cohort, salivary pepsin 24.9 ng/mL was 86% sensitive (64%, 97%) and 100.0 ng/mL was 72% specific for distinguishing NERD from functional heartburn. Given modest sensitivity and specificity for GERD, salivary pepsin may have clinical utility as a noninvasive office based diagnostic screening tool for GERD.

Gastroesophageal reflux and asthma: when, how, and why

PURPOSE OF REVIEW

Gastro-esophageal reflux is a possible cause of uncontrolled symptoms of asthma and should be actively investigated and treated before severe asthma is diagnosed and biological therapy started.

RECENT FINDINGS

Recent investigations on esophageal function and tissue biomarkers in patients with asthma and associated GERD have established a relevant role for esophageal motility and neuronal sensory abnormalities in linking the two diseases. Characterization of the underpinning inflammatory substrate has showed mixed results as both neutrophilic and eosinophilic type 2 inflammatory changes have been described.

SUMMARY

New findings regarding inflammatory mechanisms in GERD-associated asthma as well as new diagnostic tools to investigate functional esophageal abnormalities and characterize asthma endotype have identified potential treatable traits that may improve the clinical management and outcome of asthmatic patients with GERD.