Mucin gene expression in reflux laryngeal mucosa: histological and in situ hybridization observations

3D printed transwell-integrated nose-on-chip model to evaluate effects of air flow-induced mechanical stresses on mucous secretion

While there are many chip models that simulate the air-tissue interface of the respiratory system, only a few represent the upper respiratory system. These chips are restricted to unidirectional flow patterns that are not comparable to the highly dynamic and variable flow patterns found in the native nasal cavity. Here we describe the development of a tunable nose-on-chip device that mimics the air-mucosa interface and is coupled to an air delivery system that simulates natural breathing patterns through the generation of bi-directional air flow. Additionally, we employ computational modeling to demonstrate how the device design can be tuned to replicate desired mechanical characteristics within specific regions of the human nasal cavity. We also demonstrate how to culture human nasal epithelial cell line RPMI 2650 within the lab-on-chip (LOC) device. Lastly, Alcian Blue histological staining was performed to label mucin proteins, which play important roles in mucous secretion. Our results revealed that dynamic flow conditions can increase mucous secretion for RPMI 2650 cells, when compared to no flow, or stationary, conditions.

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.

Association between laryngopharyngeal reflux and benign vocal folds lesions: A systematic review

OBJECTIVES

To investigate the role of laryngopharyngeal reflux (LPR) in the development of benign lesions of the vocal folds (BLVF).

METHODS

PubMed, Cochrane Library, and Scopus were searched by three independent investigators for articles published between January 1990 and November 2018 providing substantial information about the role of LPR in the development of nodules, polyps, cysts, Reinke's edema, and sulcus vocalis. Inclusion, exclusion, diagnostic criteria and clinical outcome evaluation of included studies were analyzed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria.

RESULTS

Of the 155 relevant publications, 42 studies were included. Thirty-five were clinical studies and seven were experimental research studying the impact of reflux on vocal fold tissue. Only seven clinical studies utilized objective LPR diagnoses (pH monitoring), suggesting an association between LPR and the development of nodules, polyps, and Reinke's edema. These studies were characterized by a substantial heterogeneity due to discrepancies in inclusion/exclusion criteria, diagnostic methods, and clinical outcome evaluation. The few basic science studies on this topic support that LPR creates an environment that may predispose to BLVF through changes in defense mechanisms of the vocal folds, cell-to-cell dehiscence, inflammatory reaction of the vocal folds, and reaction to phonotrauma.

CONCLUSIONS

Caustic mucosal injury from LPR could cause increased susceptibility of the vocal fold mucosa to injury and subsequent formation of nodules, polyps, or Reinke's edema. However, the heterogeneity and the low number of high-quality studies limit the ability to draw definitive conclusions. Future clinical and experimental studies are needed to better identify the role of reflux in development of BLVF. Laryngoscope, 129:E329-E341, 2019.

Evaluation and Management of Laryngopharyngeal Reflux Disease: State of the Art Review

OBJECTIVE

To review the current literature about the epidemiology, clinical presentation, diagnosis, and treatment of laryngopharyngeal reflux (LPR).

DATA SOURCES

PubMed, Cochrane Library, and Scopus.

METHODS

A comprehensive review of the literature on LPR epidemiology, clinical presentation, diagnosis, and treatment was conducted. Using the PRISMA statement, 3 authors selected relevant publications to provide a critical analysis of the literature.

CONCLUSIONS

The important heterogeneity across studies in LPR diagnosis continues to make it difficult to summarize a single body of thought. Controversies persist concerning epidemiology, clinical presentation, diagnosis, and treatment. No recent epidemiologic study exists regarding prevalence and incidence with the use of objective diagnostic tools. There is no survey that evaluates the prevalence of symptoms and signs on a large number of patients with confirmed LPR. Regarding diagnosis, an increasing number of authors used multichannel intraluminal impedance-pH monitoring, although there is no consensus regarding standardization of the diagnostic criteria. The efficiency of proton pump inhibitor (PPI) therapy remains poorly demonstrated and misevaluated by incomplete clinical tools that do not take into consideration many symptoms and extralaryngeal findings. Despite the recent advances in knowledge about nonacid LPR, treatment protocols based on PPIs do not seem to have evolved.

IMPLICATIONS FOR PRACTICE

The development of multichannel intraluminal impedance-pH monitoring and pepsin and bile salt detection should be considered for the establishment of a multiparameter diagnostic approach. LPR treatment should evolve to a more personalized regimen, including diet, PPIs, alginate, and magaldrate according to individual patient characteristics. Multicenter international studies with a standardized protocol could improve scientific knowledge about LPR.