Vocal Fold Epithelial Barrier in Health and Injury: A Research Review

Abstract

Purpose Vocal fold epithelium is composed of layers of individual epithelial cells joined by junctional complexes constituting a unique interface with the external environment. This barrier provides structural stability to the vocal folds and protects underlying connective tissue from injury while being nearly continuously exposed to potentially hazardous insults including environmental or systemic-based irritants such as pollutants and reflux, surgical procedures, and vibratory trauma. Small disruptions in the epithelial barrier may have a large impact on susceptibility to injury and overall vocal health. The purpose of this article is to provide a broad-based review of our current knowledge of the vocal fold epithelial barrier. Methods A comprehensive review of the literature was conducted. Details of the structure of the vocal fold epithelial barrier are presented and evaluated in the context of function in injury and pathology. The importance of the epithelial-associated vocal fold mucus barrier is also introduced. Results/Conclusions Information presented in this review is valuable for clinicians and researchers as it highlights the importance of this understudied portion of the vocal folds to overall vocal health and disease. Prevention and treatment of injury to the epithelial barrier is a significant area awaiting further investigation.

Topical protection of mice laryngeal mucosa using the natural product cashew gum

“…An in vitro study using rabbit esophageal mucosa showed a great correlation between TER reduction and increased permeability after exposure to a weakly acidic solution containing bile acids . Therefore, permeability to fluorescein could be a valuable marker of a reduction in the laryngeal epithelial barrier . Accordingly, there is great clinical potential of substances that can prevent this loss of the epithelial barrier and the subsequent increase in permeability caused by the contact of bile acid with the laryngeal mucosa.…”

Process of tight junction recovery in the injured vocal fold epithelium: Morphological and paracellular permeability analysis

“…The vocal fold stratified squamous epithelium (SSE) is reported to have TJ‐based functional barrier properties . Previous studies of the vocal fold epithelium have revealed the deterioration of the functional barrier from various external stimuli such as cigarette smoke, acid reflux, histamine, infection, surgical injury, and phonotrauma, and confirmed the gene and protein expression of TJ proteins ocln and ZO‐1 in the vocal fold tissue .…”

Tissue engineering-based therapeutic strategies for vocal fold repair and regeneration

“…Vocal folds can be described as two biomechanical layers: the body (thyroarytenoid muscle and DLP) and the cover (epithelium and SLP),[26,28,29] with a main difference between the cover and body layers arising from differences in their oscillation properties. The cover is characterized by its pliability and propagation of oscillatory waves in response to the contraction of the stiff body layer.…”