The Potential Role of Bile Acids in Acquired Laryngotracheal Stenosis

Airway stenosis: classification, pathogenesis, and clinical management

Airway stenosis (AS) is a fibroinflammatory disease characterized by abnormal activation of fibroblasts and excessive synthesis of extracellular matrix, which has puzzled many doctors despite its relatively low prevalence. Traditional treatment such as endoscopic surgery, open surgery, and adjuvant therapy have many disadvantages and are limited in the treatment of patients with recurrent AS. Therefore, it is urgent to reveal the pathogenesis of AS and accelerate its clinical transformation. Based on the discovered pathogenesis, including fibrosis, inflammation, epithelial-mesenchymal transition, metabolic reprogramming, microbiome, genetic susceptibility, and other mechanisms, researchers have developed a series of treatments, such as drug therapy, gene therapy, stem cell therapy, growth factor therapy, protein therapy, and photodynamic therapy. This review introduces the classification of AS, explores the existing pathogenesis and preclinical treatments developed based on the pathogenesis, and finally summarizes the current clinical management. In addition, the prospect of exploring the interaction between different types of cells and between microorganisms and cells to identify the intersection of multiple mechanisms based on single-cell RNA sequencing, 16S rRNA gene sequencing and shotgun metagenomic sequencing is worth looking forward to.

POSTN Regulates Fibroblast Proliferation and Migration in Laryngotracheal Stenosis Through the TGF-β/RHOA Pathway

OBJECTIVES

To investigate the role of periostin (POSTN) and the transforming growth factor β (TGF-β) pathway in the formation of laryngotracheal stenosis (LTS) scar fibrosis and to explore the specific signaling mechanism of POSTN-regulated TGF-β pathway in tracheal fibroblasts.

METHODS

Bioinformatics analysis was performed on scar data sets from the GEO database to preliminarily analyze the involvement of POSTN and TGF-β pathways in fibrosis diseases. Expression of POSTN and TGF-β pathway-related molecules was analyzed in LTS scar tissue at the mRNA and protein levels. The effect of POSTN on the biological behavior of tracheal fibroblasts was studied using plasmid DNA overexpression and siRNA silencing techniques to regulate POSTN expression and observe the activation of TGF-β1 and the regulation of cell proliferation and migration via the TGF-β/RHOA pathway.

RESULTS

The bioinformatics analysis revealed that POSTN and the TGF-β pathway are significantly involved in fibrosis diseases. High expression of POSTN and TGF-β/RHOA pathway-related molecules (TGFβ1, RHOA, CTGF, and COL1) was observed in LTS tissue at both mRNA and protein levels. In tracheal fibroblasts, overexpression or silencing of POSTN led to the activation of TGF-β1 and regulation of cell proliferation and migration through the TGF-β/RHOA pathway.

CONCLUSION

POSTN is a key molecule in scar formation in LTS, and it regulates the TGF-β/RHOA pathway to mediate the formation of cicatricial LTS by acting on TGF-β1. This study provides insights into the molecular mechanisms underlying LTS and suggests potential therapeutic targets for the treatment of this condition.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:4078-4087, 2024.

The Dubai Definition and Diagnostic Criteria of Laryngopharyngeal Reflux: The IFOS Consensus

OBJECTIVE

The objective of this work was to gather an international consensus group to propose a global definition and diagnostic approach of laryngopharyngeal reflux (LPR) to guide primary care and specialist physicians in the management of LPR.

METHODS

Forty-eight international experts (otolaryngologists, gastroenterologists, surgeons, and physiologists) were included in a modified Delphi process to revise 48 statements about definition, clinical presentation, and diagnostic approaches to LPR. Three voting rounds determined a consensus statement to be acceptable when 80% of experts agreed with a rating of at least 8/10. Votes were anonymous and the analyses of voting rounds were performed by an independent statistician.

RESULTS

After the third round, 79.2% of statements (N = 38/48) were approved. LPR was defined as a disease of the upper aerodigestive tract resulting from the direct and/or indirect effects of gastroduodenal content reflux, inducing morphological and/or neurological changes in the upper aerodigestive tract. LPR is associated with recognized non-specific laryngeal and extra-laryngeal symptoms and signs that can be evaluated with validated patient-reported outcome questionnaires and clinical instruments. The hypopharyngeal-esophageal multichannel intraluminal impedance-pH testing can suggest the diagnosis of LPR when there is >1 acid, weakly acid or nonacid hypopharyngeal reflux event in 24 h.

CONCLUSION

A global consensus definition for LPR is presented to improve detection and diagnosis of the disease for otolaryngologists, pulmonologists, gastroenterologists, surgeons, and primary care practitioners. The approved statements are offered to improve collaborative research by adopting common and validated diagnostic approaches to LPR.

LEVEL OF EVIDENCE

5 Laryngoscope, 134:1614-1624, 2024.

Mechanisms of fibrosis in iatrogenic laryngotracheal stenosis: New discoveries and novel targets

Iatrogenic laryngotracheal stenosis (iLTS) is a pathological condition characterized by the narrowing of the laryngeal and tracheal structures due to the formation of abnormal scar tissue. The core of iLTS lies in the fibrosis of the laryngotracheal tissue, and recent research has unveiled novel discoveries regarding the underlying mechanisms of fibrosis. This review provides an overview of the recent advancements in understanding the mechanisms of fibrosis in iLTS. It encompasses various aspects, such as immune system dysregulation, changes in the extracellular matrix (ECM), metabolic alterations, and the role of microbial flora. The review also explores the interplay and relationships between these new mechanisms, establishing a theoretical foundation for the development of multi-target therapies and combination therapies for iLTS.

Amprenavir inhibits pepsin-mediated laryngeal epithelial disruption and E-cadherin cleavage in vitro

Background

Laryngopharyngeal reflux (LPR) causes chronic cough, throat clearing, hoarseness, and dysphagia and can promote laryngeal carcinogenesis. More than 20% of the US population suffers from LPR and there is no effective medical therapy. Pepsin is a predominant source of damage during LPR which disrupts laryngeal barrier function potentially via E-cadherin cleavage proteolysis and downstream matrix metalloproteinase (MMP) dysregulation. Fosamprenavir (FDA-approved HIV therapeutic and prodrug of amprenavir) is a pepsin-inhibiting LPR therapeutic candidate shown to rescue damage in an LPR mouse model. This study aimed to examine amprenavir protection against laryngeal monolayer disruption and related E-cadherin proteolysis and MMP dysregulation in vitro.

Methods

Laryngeal (TVC HPV) cells were exposed to buffered saline, pH 7.4 or pH 4 ± 1 mg/mL pepsin ± amprenavir (10-60 min). Analysis was performed by microscopy, Western blot, and real time polymerase chain reaction (qPCR).

Results

Amprenavir (1 μM) rescued pepsin acid-mediated cell dissociation (p < .05). Pepsin acid caused E-cadherin cleavage indicative of regulated intramembrane proteolysis (RIP) and increased MMP-1,3,7,9,14 24-h postexposure (p < .05). Acid alone did not cause cell dissociation or E-cadherin cleavage. Amprenavir (10 μM) protected against E-cadherin cleavage and MMP-1,9,14 induction (p < .05).

Conclusions

Amprenavir, at serum concentrations achievable provided the manufacturer's recommended dose of fosamprenavir for HIV, protects against pepsin-mediated cell dissociation, E-cadherin cleavage, and MMP dysregulation thought to contribute to barrier dysfunction and related symptoms during LPR. Fosamprenavir to amprenavir conversion by laryngeal epithelia, serum and saliva, and relative drug efficacies in an LPR mouse model are under investigation to inform development of inhaled formulations for LPR.

Idiopathic subglottic stenosis arises at the epithelial interface of host and pathogen

Background

Idiopathic subglottic stenosis (iSGS) is a rare fibrotic disease of the proximal airway affecting adult Caucasian women nearly exclusively. Life-threatening ventilatory obstruction occurs secondary to pernicious subglottic mucosal scar. Disease rarity and wide geographic patient distribution has previously limited substantive mechanistic investigation into iSGS pathogenesis.

Result

By harnessing pathogenic mucosa from an international iSGS patient cohort and single-cell RNA sequencing, we unbiasedly characterize the cell subsets in the proximal airway scar and detail their molecular phenotypes. Results show that the airway epithelium in iSGS patients is depleted of basal progenitor cells, and the residual epithelial cells acquire a mesenchymal phenotype. Observed displacement of bacteria beneath the lamina propria provides functional support for the molecular evidence of epithelial dysfunction. Matched tissue microbiomes support displacement of the native microbiome into the lamina propria of iSGS patients rather than disrupted bacterial community structure. However, animal models confirm that bacteria are necessary for pathologic proximal airway fibrosis and suggest an equally essential role for host adaptive immunity. Human samples from iSGS airway scar demonstrate adaptive immune activation in response to the proximal airway microbiome of both matched iSGS patients and healthy controls. Clinical outcome data from iSGS patients suggests surgical extirpation of airway scar and reconstitution with unaffected tracheal mucosa halts the progressive fibrosis.

Conclusion

Our data support an iSGS disease model where epithelial alterations facilitate microbiome displacement, dysregulated immune activation, and localized fibrosis. These results refine our understanding of iSGS and implicate shared pathogenic mechanisms with distal airway fibrotic diseases.

Impact of Helicobacter pylori Infection and Outcome of Anti-Helicobacter pylori Therapy in Patients with Reflux Laryngopharyngitis

Objectives

This study was designed to explore the relationship between Helicobacter pylori (Hp) infection and reflux laryngopharyngitis (RLP) and to evaluate the outcome of anti-Hp therapy in improving RLP symptoms.

Methods

A total of 410 patients with RLP were enrolled and tested for Hp infection. The association of Hp infection with reflux symptom index (RSI) and reflux finding score (RFS) was determined. Hp-positive patients received either a proton pump inhibitor (PPI) omeprazole alone (control group) or a combination regimen (experimental group) consisting of omeprazole, mosapride citrate, amoxicillin, and clarithromycin. Therapeutic outcomes were compared 4 weeks later.

Results

Of the 410 participants, 290 were Hp-positive and 120 Hp-negative. Both RSI and RFS were significantly higher in Hp-positive patients than in Hp-negative patients. Hp infection status was positively correlated with RSI (P < 0.05) and RFS (P < 0.05). The overall response rate was higher in the experimental group than in the control group. Both the groups had a significant reduction in RSI and RFS after therapy, with a greater improvement in the experimental group (P < 0.05).

Conclusion

Our findings establish a link between Hp infection and RLP. Anti-Hp therapy improves RSI and RFS in RLP patients. Therefore, Hp eradication drugs may be added to the PPI-based regimen in the treatment of RLP.

Clinical, Histological, and Profibrotic Extracellular Matrix Protein Changes in a Model of Tracheal Stenosis Induced by Cervical Tracheal Autotransplantation

BACKGROUND

Tracheal stenosis (TS) is a complication of prolonged intubation, tracheotomy, and tracheal surgery that compromises the vascular supply. Animal models are essential for studying its pathophysiology and the effect of interventions.

OBJECTIVE

To establish a TS model in rats secondary to tracheal autotransplantation with a graft submerged in bleomycin (Atx-Bleo). Additionally, to evaluate the clinical and histological changes, as well as the expression of newly formed collagen (NFC), isoforms of transforming growth factor beta (TGFβ), fibronectin (FN), elastin (ELN), integrin β1 (ITGβ1), and matrix metalloproteinase 1 (MMP1) in TS.

METHODS

Twenty Wistar rats were divided into three groups: group I (n = 20) control; group II (n = 10) end-to-end anastomosis of the trachea (tracheoplasty); and group III (n = 10) Atx-Bleo. The animals were evaluated clinically, tomographically, macroscopically, morphometrically, and microscopically. NFC deposition, and the expression of profibrotic and antifibrotic proteins were evaluated in tracheal scars.

RESULTS

All animals survived the surgical procedure and the study period. Compared with the other study groups, the Atx-Bleo group developed TS and fibrosis, exhibited higher expression of NFC, TGFβ1, TGFβ2, FN, ELN, and ITGβ1, and mild expression of TGFβ3 and MMP1 (p < 0.005; analysis of variance, Dunnett and Tukey tests).

CONCLUSION

Atx-Bleo in TS model rats produces tomographic and histological changes, and induces the upregulation of profibrotic proteins (TGFβ1, TGFβ2, collagen, FN, ELN, ITGβ1) and downregulation of antifibrotic proteins (TGFβ3, MMP1). Therefore, this model may be used to test new pharmacological treatments for reversing or preventing TS, and conduct basic studies regarding its pathophysiology.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Laryngopharyngeal Reflux and Inflammatory Responses in Mucosal Barrier Dysfunction of the Upper Aerodigestive Tract

The upper aerodigestive tract (UAT) is the first line of defense against environmental stresses such as antigens, microbes, inhalants, foods, etc., and mucins, intracellular junctions, epithelial cells, and immune cells are the major constituents of this defensive mucosal barrier. Laryngopharyngeal reflux (LPR) is recognized as an independent risk factor for UAT mucosal disorders, and in this review, we describe the components and functions of the mucosal barrier and the results of LPR-induced mucosal inflammation in the UAT. We discuss the interactions between the refluxate and the mucosal components and the mechanisms through which these damaging events disrupt and alter the mucosal barriers. In addition, we discuss the dynamic alterations in the mucosal barrier that might be potential therapeutic targets for LPR-induced disorders.

Management of laryngopharyngeal reflux in Brazil: a national survey

INTRODUCTION

Studies assessing the management of laryngopharyngeal reflux by otolaryngologists have reported an important heterogeneity regarding the definition, diagnosis, and treatment, which leads to discrepancies in the management of the patient. Information about the current knowledge and practices of Brazilian otolaryngologists in laryngopharyngeal reflux is lacking.

OBJECTIVE

To investigate the trends in management of laryngopharyngeal reflux disease among Brazilian otolaryngologists.

METHODS

A survey was sent by email to the members of the Brazilian Association of Otolaryngology-Head Neck Surgery. This survey has initially been conducted by the laryngopharyngeal reflux study group of young otolaryngologists of the International Federation of Otolaryngological Societies.

RESULTS

According to the survey responders, the prevalence of laryngopharyngeal reflux was estimated to be 26.8% of patients consulting in otolaryngology and the most common symptoms were globus sensation, throat clearing, cough and stomach acid reflux. Nasal obstruction, Eustachian tube dysfunction, acute and chronic otitis media, vocal fold nodules and hemorrhage were considered not associated with laryngopharyngeal reflux by the majority of responders. About 2/3 of Brazilian otolaryngologists based the diagnosis of laryngopharyngeal reflux on the assessment of both symptoms and findings and a positive response to empiric therapeutic trials. Proton pump inhibitor utilized once or twice daily, was the most commonly used therapeutic scheme. Only 21.4% of Brazilian otolaryngologists have heard about nonacid and mixed laryngopharyngeal reflux and the awareness about the usefulness of multichannel intraluminal impedance pH monitoring (MII-pH) was minimal; 30.5% of responders did not consider themselves as well-informed about laryngopharyngeal reflux.

CONCLUSION

Although the laryngopharyngeal reflux-related symptoms, main diagnostic and treatment approaches referred by Brazilian otolaryngologists are consistent with the literature, the survey identified some limitations, such as the insufficient awareness of the role of laryngopharyngeal reflux in many otolaryngological conditions and of the possibility of non-acid or mixed reflux in refractory cases. Future studies are needed to establish international recommendations for the management of laryngopharyngeal reflux disease.

Impact of bile acids on the severity of laryngo-pharyngeal reflux

OBJECTIVES

The primary end point of this study was to evaluate the impact of bile acids on severity of laryngo-pharyngeal reflux (LPR) and the possible correlation with esophagitis and upper airway malignancies. The second end point was to evaluate if salivary bile acids and molecules other than pepsin might serve as diagnostic biomarkers of LPR.

DESIGN

Observational prospective comparative study.

SETTING

Otorhinolaryngology unit of a tertiary hospital.

PARTICIPANTS

Sixty-two consecutive adult outpatients suspected of LPR.

MAIN OUTCOME MEASURES

Bile acids, bilirubin and pepsinogen I-II were measured in saliva. Patients underwent pH metry and based on the results of bile acids were subdivided as acid, mixed and alkaline LPR.

RESULTS

Significantly higher Reflux Findings Score (RFS) and Reflux Symptoms Index (RSI) were seen in patients with alkaline and mixed LPR compared to acid LPR. Salivary bile acids >1 µmol/L seem to be a reliable indicator of the severity of LPR. Compared to those without, patients with esophagitis or a history of upper airway malignancy have high concentrations of bile acids in saliva. Among the molecules studied, bile acids were the most suitable for diagnosis of LPR, with a sensitivity of 86% and a positive predictive value of 80.7%.

CONCLUSIONS

Our data suggest that high concentrations of bile acids are associated with higher values of RSI and RFS in LPR as well as a higher risk of esophagitis and history of upper airway malignancies. We finally observed that bile acids provided the best biometric parameters for diagnosis of LPR among the molecules tested.

Involvement of Laryngopharyngeal Reflux in Select Nonfunctional Laryngeal Diseases: A Systematic Review

Objectives

To investigate the existing published evidence supporting the role of laryngopharyngeal reflux (LPR) in the development of the select nonfunctional laryngeal diseases of laryngotracheal stenosis, granuloma, leukoplakia, and laryngeal infections

Data Sources

PubMed, Cochrane Library, and Scopus.

Review Methods

A systematic review was performed by 3 independent investigators for studies providing information about the prevalence and role of LPR in the development of laryngotracheal stenosis, granuloma, leukoplakia, and laryngeal infections. Diagnostic criteria and clinical outcome evaluation of included studies were analyzed with PRISMA criteria.

Results

Of the 64 relevant publications, 27 clinical and 4 basic science studies were included. Ten studies used objective reliable examinations for LPR diagnosis (eg, dual- or triple-probe or oropharyngeal pH monitoring, multichannel intraluminal impedance–pH monitoring, or pepsin detection). According to the bias analysis and the results of studies, the association between LPR and laryngotracheal stenosis, leukoplakia, laryngeal papillomatosis, or vocal fold granuloma remains poorly demonstrated. There is a notable heterogeneity among included studies regarding their inclusion criteria, diagnostic methods, and clinical outcome evaluation. Although some experimental findings support the involvement of bile salts and other gastroduodenal proteins active in alkaline pH, no included clinical studies assessed the role of nonacid and mixed reflux through multichannel intraluminal impedance–pH monitoring.

Conclusion

The involvement of LPR in the development of leukoplakia, laryngotracheal stenosis, vocal fold granuloma, and laryngeal papillomatosis is currently not demonstrated. The potential relationship between LPR and these select nonfunctional laryngeal diseases must be confirmed through future clinical and experimental studies considering acid, nonacid, and mixed LPR.

The role of nonacid reflux in laryngopharyngeal reflux diseases

OBJECTIVE

To analyze the role of nonacid reflux in laryngopharyngeal reflux diseases (LPRD).

METHODS

From January 2014 to April 2019, 344 patients associated with LPRD underwent 24-h multichannel intraluminal impedance-pH monitoring, and their reflux symptom index (RSI) and reflux finding score (RFS) were recorded. The numbers of acid, weakly acidic and alkaline reflux events in the laryngopharynx were counted, and the consistency analysis of the results with the results of the RSI and RFS was conducted.

RESULTS

Among the 344 patients, nonacid reflux events accounted for 74.1% (1367/1845) of the all reflux events. There were 111 patients with ≥ 3 acid reflux events, 218 patients with ≥ 3 any kinds of reflux events, and 257 patients with positive results of RSI or RFS. Taking the results of the RSI and or RFS as a reference, the sensitivity, specificity and consistency test Kappa value for the diagnosis of LPRD according to the existence of ≥ 3 acid reflux events were 41.2%, 94.2% and 0.228, respectively. With the existence of three or more all kinds of reflux events as the standard, the sensitivity, specificity and consistency test Kappa value were 76.7%, 74.7% and 0.449, respectively.

CONCLUSION

The nonacid reflux events account for the highest proportion of laryngopharyngeal reflux events, and the consistency of the results of RSI and or RFS with all reflux events is higher than that with only acid reflux events, that indicates nonacid reflux may play an important role in LPRD.

Do Laryngologists and General Otolaryngologists Manage Laryngopharyngeal Reflux Differently?

OBJECTIVE

To investigate current practices of laryngologists and non-laryngologists in management of Laryngopharyngeal Reflux (LPR).

METHODS

An online survey was sent to members of otolaryngology societies about LPR, and subgroup analysis was performed between laryngologists and non-laryngologists. This survey was conducted by the LPR Study Group of Young Otolaryngologists of the International Federation of Otolaryngological Societies.

RESULTS

A total of 535 otolaryngologists completed the survey. Among them, 127 were laryngologists and 408 were non-laryngologists. Collectively, symptoms most commonly attributed to LPR are cough after lying down/meal, throat clearing, and acid brash; most common findings are thought to be arytenoid erythema and posterior commissure hypertrophy. Respectively, 12.5% and 5% of non-laryngologists and laryngologists believe that ≥50% of LPR patients suffer from heartburn (P = .010). Non-laryngologists are more aware about some extra-laryngeal findings associated with LPR (eg, pharyngeal erythema) than laryngologists. Neither laryngologists nor non-laryngologists associated development of benign lesions of the vocal folds with reflux. The management of LPR substantially differs between groups, with laryngologists indicating increased awareness of (impedance)-pH monitoring as well as the prevalence and treatment of nonacid/mixed LPR. Conversely, non-laryngologists are much more likely to include gastroenterology referral in their management of presumed LPR. Respectively, 44.8% and 27.6% of non-laryngologists and laryngologists believe themselves not sufficiently knowledgeable about LPR.

CONCLUSIONS

Significant differences exist between laryngologists and non-laryngologists in diagnosis and treatment of LPR. Overall only one-third of responders believe themselves to be sufficiently educated about LPR.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E539-E547, 2020.

Awareness of European Otolaryngologists and General Practitioners Toward Laryngopharyngeal Reflux

OBJECTIVES

To investigate the current trends in management of laryngopharyngeal reflux (LPR) among young European otolaryngologists and general practitioners (GP).

METHODS

An international survey was sent to European general practitioners and all otolaryngologists under 45 years old from the 2017 IFOS meeting. This survey was conducted by the LPR Study Group of YO-IFOS (Young Otolaryngologists of the International Federation of Otolaryngological Societies).

RESULTS

Among the 2500 attendees, 230 European otolaryngologists (response rate = 9%) completed the survey; an additional 70 GPs also completed the survey. GPs did not differentiate between gastroeosophageal reflux disease (GERD) and LPR, overstating GERD-related symptoms (ie, heartburn and regurgitations) in LPR clinical presentation and relying on gastrointestinal endoscopy for LPR diagnosis. Otolaryngologists also believe that GERD-related symptoms are prevalent in LPR. Knowledge of nonacid and mixed LPR and use of multichannel intraluminal impedance-pH monitoring are still limited in both groups. A therapeutic dichotomy exists between groups: GPs mainly use a 4-week once daily empiric proton pump inhibitors (PPIs) trial, while otolaryngologists use PPIs twice daily for a longer therapeutic period ranging from 8 to 12 weeks. More than 50% of GPs and otolaryngologists believe that they are not adequately knowledgeable and skilled about LPR.

CONCLUSION

The majority of GPs and otolaryngologists do not believe themselves to be sufficiently informed about LPR, leading to different practice patterns and grey areas. The elaboration of international recommendations in the management of reflux is needed to improve practices.

Optimized Generation of Primary Human Epithelial Cells from Larynx and Hypopharynx: A Site-Specific Epithelial Model for Reflux Research

Laryngopharyngeal reflux (LPR) induces a differential damage effect on several anatomic sites within the larynx and hypopharynx; therefore, an in vitro model is needed for each anatomic site. This study aimed to establish a primary culture method for human laryngeal and hypopharyngeal epithelial cells derived from multiple anatomic sites. Surgical mucosa specimens were treated with a two-step enzymatic strategy to establish a primary culture. Of the 46 samples, primary cultivation was achieved successfully with 36 samples, and the positive ratio was 78.3%. In addition, flow cytometry revealed that these primary cells were epithelial cells with a purity of 94.9%. The proliferative ability was confirmed by positive staining for Ki-67. Laryngeal and hypopharyngeal epithelial cells from multiple sites exhibited similar epithelial morphology and positive cytokeratin expression. These cells can be cultured to passage 4. In summary, we successfully established the in vitro epithelial model of larynx and hypopharynx subsites, which may potentially be used as a platform for reflux research, especially for site-specific damage effect.

Perspectives on the interlinked nature of systemic sclerosis and reflux disease

Systemic sclerosis (SSc) is a multisystem connective tissue disease, characterized by chronic inflammation and vascular changes that result in esophageal smooth muscle atrophy and fibrosis. Subsequent progressive loss of peristalsis in the distal esophagus and loss of lower esophageal sphincter function lead to problems with the protective barrier and exposure of sensitive tissues to the gastroduodenal contents, a disorder called reflux disease. Areas covered: Depending on the range, nature and symptoms of the disease, the term 'reflux disease' may refer to gastroesophageal reflux, laryngopharyngeal reflux, microaspiration into the airways and silent reflux. Despite the links between these visceral complications, this connection remains controversial. This is due to a lack of complete understanding, the asymptomatic nature of the disease and the limited diagnostic accuracy of tests, which can delay diagnosis. Such delays are problematic, given that the early detection of GERD in SSc patients, the timing of assessment, the treatment of the organs involved are critical aspects of patient prognosis and disease outcome. Expert commentary: This review summarizes the most recent knowledge about the pathophysiology, diagnosis and prospective treatment of GERD in SSc patients and highlights how innovative technologies applied through an integrative, interdisciplinary approach may soon lead to effective treatment strategies.

The role of pepsin in epithelia-mesenchymal transition in idiopathic subglottic stenosis

OBJECTIVES

Idiopathic subglottic stenosis (iSGS) is commonly characterized by laryngeal fibrosis thought to arise by epithelia-mesenchymal transition (EMT) induced by chronic inflammation. Pepsin is a potent inducer of inflammation in the airways during chronic laryngopharyngeal reflux and has been observed in the subglottic mucosa of patients with iSGS, absent in normal mucosa. The aim of this study was to examine the effect of pepsin on mechanisms of EMT in laryngeal cells with implications for iSGS.

STUDY DESIGN

In vitro translational research study.

METHODS

Human laryngeal epithelial cell cultures were exposed to 0.1 mg/mL or 1.0 mg/mL pepsin at pH7 for 24 and 48 hours, or media pH5 ± 0.1 mg/mL pepsin for 10 minutes and harvested after 24 and 48 hours. EMT marker expression was measured by qPCR and enzyme-linked immunosorbent assays. Wound-healing scratch assay was performed on immortalized human vocal fold fibroblasts pretreated with media pH5 ± 0.1 mg/mL pepsin (10 minutes) or continuously treated with media pH7 ± 0.1 to 1 mg/mL pepsin for 24 hours.

RESULTS

Pepsin yielded no effect on MMP1, MMP9, FN1, COL1A1, HAS2, or CDH1 gene expression or matrix metalloproteinase-9 or fibronectin protein expression, either alone or in the presence of weak acid. Pepsin and/or acid produced no effect on fibroblast migration.

CONCLUSION

Whereas pepsin has been shown to be present in the subglottic mucosa of patients with iSGS, this in vitro acute exposure investigation does not provide evidence of a direct causal role for development of fibrosis in subglottic epithelial cell cultures.

LEVELS OF EVIDENCE

NA. Laryngoscope, 130:154-158, 2020.

Establishment of an immortalized human subglottic epithelial cell line

Objective

Translational research into subglottic disease is restricted by the availability of primary human tissue originating from this subsite. Primary epithelial cells are also limited by their inability to survive beyond several divisions in culture outside of the body. Specific subglottic cell lines, useful for in vitro studies, have not yet been described. We therefore demonstrate what we believe to be the first immortalized subglottic epithelial cell line.

Methods

Subglottic tissue was derived from a single adult patient's neoplasia‐free human subglottic brushing specimen. Cells were immortalized using a lentiviral vector expressing simian virus 40 T antigen. Karyotyping was performed on the transformed cells using single nucleotide polymorphism array comparative genomic hybridization. Transformed cells were phenotypically characterized by light microscopy, immunohistochemistry, and electrophysiology studies.

Results

The immortalized subglottic cell line (SG01) was able to divide successfully beyond 20 passages. Karyotyping demonstrated no significant genomic imbalance after immortalization. The cells demonstrated normal epithelial morphology and cytokeratin expression throughout. SG01 cells were also successfully cultured at air–liquid interface (ALI). At ALI cells demonstrated cilia, mucus production, and relevant ion channel expression.

Conclusion

The novel SG01 subglottic epithelial cell line has been established. This cell line provides a unique resource for researchers to investigate subglottic diseases, such as subglottic stenosis.

Level of Evidence

NA. Laryngoscope, 129:2640–2645, 2019

Etiology, pathogenesis, diagnosis and treatment of bile reflux gastritis

Bile reflux gastritis is a common disease of the digestive system, whose clinical characteristics are abdominal pain, abdominal distention and nausea and vomiting, affecting the quality of life of patients seriously. However, the etiology and pathogenesis of bile reflux gastritis are still unclear, which may be related to gastrointestinal surgery, gallbladder disease, Helicobacter pylori infection, psychological factors, etc. There are many diagnostic methods, but a consensus on diagnosis is still lacking. Most of the current treatments are symptomatic treatments, but the overall efficacy is poor. This article reviews the etiology, pathogenesis, diagnosis and treatment of bile reflux gastritis, with an aim to provide a reference for further research of this disease.