Differential Bile Acid Detection in Refractory GERD Patient Saliva Using a Simple and Sensitive Liquid Chromatography Tandem Mass Spectrometry Approach

Pilot study evaluating salivary bile acids as a diagnostic biomarker of laryngopharyngeal reflux

Bile acids in refluxate contribute to esophageal and laryngeal symptoms and are quantifiable. The aim of this study was to compare salivary bile acid concentrations across healthy controls and symptomatic patients (esophageal or laryngeal) with or without objective gastroesophageal reflux disease (GERD). This prospective study enrolled adults into three groups: esophageal symptoms (heartburn, regurgitation, chest pain); laryngeal symptoms (cough, throat clearing, sore throat, dysphonia); and controls. Symptomatic patients primarily underwent prolonged wireless reflux monitoring off acid suppression and were categorized as symptomatic no GERD (acid exposure time <4%) or esophageal/laryngeal symptoms with GERD (acid exposure time ≥4%). Controls did not undergo reflux monitoring nor upper endoscopy. Saliva samples were provided for bile acid analysis via ultraperformance liquid chromatography tandem mass spectrometry. Thirty-five participants were enrolled (mean age 47.4 years [SD 18.9], 16 [46%] male), including 10 controls and 25 symptomatic: 9 no GERD, 5 esophageal symptoms + GERD, and 11 laryngeal symptoms + GERD. Total salivary bile acids were highest in the laryngeal symptoms + GERD group (24.2 nM [SD 24.7]) compared to other groups (controls: 5.8 [6.0], P = 0.03; symptomatic no GERD: 3.1 [4.4]; P < 0.01; esophageal symptoms + GERD: 7.1 [7.1], P = 0.10). Bile acids were elevated in 45% (5/11) of the laryngeal symptoms + GERD group compared to 0% of the other three groups (P < 0.01). Salivary bile acids were higher among patients with laryngeal symptoms and objective GERD versus other groups. Salivary bile acids are a quantifiable biomarker with diagnostic potential for 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.

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.