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Kimball EE, Rousseau B. Mechanotransduction in the Vocal Fold Microenvironment: A Narrative Review. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2024; 67:2128-2138. [PMID: 38865255 PMCID: PMC11253793 DOI: 10.1044/2024_jslhr-23-00718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/29/2024] [Accepted: 03/11/2024] [Indexed: 06/14/2024]
Abstract
PURPOSE The vocal fold tissues undergo nearly continuous and repeated cycles of injury and repair throughout the course of an individual's lifetime. It is well established that certain individuals are at greater risk of lesion development based on personality and behavioral classification. However, these characteristics alone do not wholly predict or explain lesion development or severity. In this review, we discuss current knowledge of mechanotransduction proteins and their potential relevance to tissue homeostasis in the vocal folds. METHOD A review of literature surrounding mechanotransduction and tissue homeostasis as it relates to the vocal folds was conducted. Review of the literature included searches of PubMed, Google Scholar, and other various online peer-reviewed sources. Search terms pertained to mechanosensation, mechanotransduction, mechanically activated channels, mechanical cellular regulation, and other associated concepts and terms. Additional literature was identified through the reference lists of identified papers. Findings of this literature review were then applied to known physiology and pathophysiology of the vocal folds in order to speculate on the contribution of mechanically mediated mechanisms within the vocal fold. DISCUSSION AND CONCLUSION Because the vocal folds are such mechanically active structures, withstanding nearly constant external forces, there is strong support for the idea that mechanically sensitive molecular pathways within the vocal fold tissue play a major role in tissue homeostasis in the presence of these considerable forces. As such, mechanotransduction within the vocal fold should be considered and targeted in future biological studies of vocal fold physiology.
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Affiliation(s)
- Emily E. Kimball
- Department of Hearing and Speech Sciences, Department of Otolaryngology – Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Bernard Rousseau
- Doisy College of Health Sciences, Saint Louis University, St. Louis, MO
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Mizuta M, Kurita T, Dillon NP, Kimball EE, Garrett CG, Sivasankar MP, Webster RJ, Rousseau B. In vivo measurement of vocal fold surface resistance. Laryngoscope 2017; 127:E364-E370. [PMID: 28573762 PMCID: PMC5607073 DOI: 10.1002/lary.26715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 04/23/2017] [Accepted: 05/03/2017] [Indexed: 11/07/2022]
Abstract
OBJECTIVES/HYPOTHESIS A custom-designed probe was developed to measure vocal fold surface resistance in vivo. The purpose of this study was to demonstrate proof of concept of using vocal fold surface resistance as a proxy of functional tissue integrity after acute phonotrauma using an animal model. STUDY DESIGN Prospective animal study. METHODS New Zealand White breeder rabbits received 120 minutes of airflow without vocal fold approximation (control) or 120 minutes of raised intensity phonation (experimental). The probe was inserted via laryngoscope and placed on the left vocal fold under endoscopic visualization. Vocal fold surface resistance of the middle one-third of the vocal fold was measured after 0 (baseline), 60, and 120 minutes of phonation. After the phonation procedure, the larynx was harvested and prepared for transmission electron microscopy. RESULTS In the control group, vocal fold surface resistance values remained stable across time points. In the experimental group, surface resistance (X% ± Y% relative to baseline) was significantly decreased after 120 minutes of raised intensity phonation. This was associated with structural changes using transmission electron microscopy, which revealed damage to the vocal fold epithelium after phonotrauma, including disruption of the epithelium and basement membrane, dilated paracellular spaces, and alterations to epithelial microprojections. In contrast, control vocal fold specimens showed well-preserved stratified squamous epithelia. CONCLUSIONS These data demonstrate the feasibility of measuring vocal fold surface resistance in vivo as a means of evaluating functional vocal fold epithelial barrier integrity. Device prototypes are in development for additional testing, validation, and for clinical applications in laryngology. LEVEL OF EVIDENCE NA Laryngoscope, 127:E364-E370, 2017.
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Affiliation(s)
- Masanobu Mizuta
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, TN†
| | - Takashi Kurita
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, TN†
| | - Neal P. Dillon
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
| | - Emily E. Kimball
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - C. Gaelyn Garrett
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, TN†
| | - M. Preeti Sivasankar
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN
| | - Robert J. Webster
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, TN†
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
- Department of Electrical Engineering, Vanderbilt University, Nashville, TN
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
- Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Bernard Rousseau
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, TN†
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN
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Mizuta M, Kurita T, Kimball EE, Rousseau B. Structurally and functionally characterized in vitro model of rabbit vocal fold epithelium. Tissue Cell 2017; 49:427-434. [PMID: 28395914 PMCID: PMC5467526 DOI: 10.1016/j.tice.2017.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/15/2017] [Accepted: 03/16/2017] [Indexed: 12/19/2022]
Abstract
In this paper, we describe a method for primary culture of a well differentiated electrically tight rabbit vocal fold epithelial cell multilayer and the measurement of transepithelial electrical resistance (TEER) for the evaluation of epithelial barrier function in vitro. Rabbit larynges were harvested and enzymatically treated to isolate vocal fold epithelial cells and to establish primary culture. Vocal fold epithelial cells were co-cultured with mitomycin C-treated feeder cells on collagen-coated plates. After 10-14 days in primary culture, cells were passaged and cultured until they achieved 70-90% confluence on collagen-coated plates. Epithelial cells were then passaged onto collagen-coated cell culture inserts using 4.5cm2 membrane filters (1.0μm pore size) with 10% fetal bovine serum or 30μg/mL bovine pituitary extract to investigate the effects of growth-promoting additives on TEER. Additional experiments were performed to investigate optimal seeding density (1.1, 2.2, 4.4, or 8.9×105 cells/cm2), the effect of co-culture with feeder cells, and the effect of passage number on epithelial barrier function. Characterization of in vitro cultures was performed using hematoxylin and eosin staining and immunostaining for vocal fold epithelial cell markers and tight junctions. Results revealed higher TEER in cells supplemented with fetal bovine serum compared to bovine pituitary extract. TEER was highest in cells passaged at a seeding density of 2.2×104 cells/cm2, and TEER was higher in cells at passage two than passage three. Ultrastructural experiments revealed a well-differentiated epithelial cell multilayer, expressing the epithelial cell markers CK13, CK14 and the tight junction proteins occludin and ZO-1.
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Affiliation(s)
- Masanobu Mizuta
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Takashi Kurita
- Department of Otolaryngology, Vanderbilt University Medical Center, 1215 21st Avenue South, Medical Center East, Nashville, TN 37232, USA
| | - Emily E Kimball
- Department of Hearing and Speech Sciences, Vanderbilt University School of Medicine, 1215 21st Avenue South, Medical Center East, Nashville, TN 37232, USA
| | - Bernard Rousseau
- Department of Otolaryngology, Vanderbilt University Medical Center, and Hearing and Speech Sciences and Mechanical Engineering, Vanderbilt University School of Medicine, Medical Center East, 1215 21st Avenue South, Nashville, TN 37232, USA.
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Durkes A, Sivasankar MP. In vivo investigation of acidified pepsin exposure to porcine vocal fold epithelia. Laryngoscope 2015; 126:E12-7. [PMID: 26153224 DOI: 10.1002/lary.25478] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/07/2015] [Accepted: 06/08/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVES/HYPOTHESIS The study objective was to investigate epithelial changes in response to direct, repeated, acidified pepsin exposures in an in vivo porcine model. We hypothesized that 12 acidified pepsin applications to simulate reflux would elicit a vocal fold response characterized by inflammation, epithelial proliferation, and increased intercellular space, as well as changes in the gene expression of epithelial junctional proteins, ion transporter proteins, and proinflammatory cytokines. STUDY DESIGN Prospective, in vivo study. METHODS Pigs received acidified pepsin (pH = 4) or saline (sham) applied directly to vocal folds. Larynges were collected following three exposures per week for 4 weeks. Vocal fold tissue morphology, collagen, and elastin were evaluated histologically. Gene expression of E-cadherin, zona occludens-1, cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, interleukin-1β, tumor necrosis factor-α, and interferon-γ were measured. Ultrastructural alterations, epithelial intercellular space diameter, and microridge height were measured using transmission electron microscopy. RESULTS There were no significant differences in histology, gene transcripts, epithelial ultrastructure, intercellular space, and microridge height after acidified pepsin exposure. CONCLUSIONS Twelve simulated reflux challenges were insufficient to elicit epithelial changes, demonstrating the resistance of healthy vocal folds to direct, repeated acidified pepsin exposures. These data increase our understanding of healthy vocal fold defenses and lay the groundwork for a prospective, uninjured, nonsurgical, laryngopharyngeal reflux model where pigs can be exposed directly to acidified pepsin.
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Affiliation(s)
- Abigail Durkes
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, U.S.A
| | - M Preeti Sivasankar
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana, U.S.A
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Durkes A, Sivasankar MP. Bicarbonate availability for vocal fold epithelial defense to acidic challenge. Ann Otol Rhinol Laryngol 2014; 123:71-6. [PMID: 24574427 DOI: 10.1177/0003489414521143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Bicarbonate is critical for acid-base tissue homeostasis. In this study we investigated the role of bicarbonate ion transport in vocal fold epithelial defense to acid challenges. Acidic insults to the larynx are common in gastric reflux, carcinogenesis and metastasis, and acute inflammation. METHODS Ion transport was measured in viable porcine vocal fold epithelium. First, 18 vocal folds were exposed to either the carbonic anhydrase antagonist acetazolamide or to vehicle. Second, 32 vocal folds were exposed to either a control buffer or a bicarbonate-free buffer on their luminal or basolateral surface or both. Third, 32 vocal folds were challenged with acid in the presence of bicarbonate-free or control buffer. RESULTS The vocal fold transepithelial resistance was greater than 300 Ω*cm(2), suggesting robust barrier integrity. Ion transport did not change after exposure to acetazolamide (p > 0.05). Exposure to bicarbonate-free buffer did not compromise vocal fold ion transport (p > 0.05). Ion transport increased after acid challenge. This increase approached statistical significance and was the greatest for the control buffer and for the bicarbonate-free buffer applied to the basolateral surface. CONCLUSIONS Bicarbonate secretion may contribute to vocal fold defense against acid challenge. Our data offer a potential novel role for bicarbonate as a therapeutic agent to reduce pH abnormalities in the larynx and prevent associated pathological changes.
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Affiliation(s)
- Abigail Durkes
- Department of Comparative Pathobiology, College of Veterinary Medicine (Durkes), Purdue University, West Lafayette, Indiana
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Levendoski EE, Leydon C, Thibeault SL. Vocal fold epithelial barrier in health and injury: a research review. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2014; 57:1679-91. [PMID: 24686981 PMCID: PMC4557797 DOI: 10.1044/2014_jslhr-s-13-0283] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 03/04/2014] [Indexed: 05/07/2023]
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 current knowledge of the vocal fold epithelial barrier. METHOD 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.
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Zhang Q, Fisher K. Tight junction-related barrier contributes to the electrophysiological asymmetry across vocal fold epithelium. PLoS One 2012; 7:e34017. [PMID: 22442739 PMCID: PMC3307777 DOI: 10.1371/journal.pone.0034017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Accepted: 02/25/2012] [Indexed: 11/18/2022] Open
Abstract
Electrophysiological homeostasis is indispensable to vocal fold hydration. We investigate tight junction (TJ)-associated components, occludin and ZO-1, and permeability with or without the challenge of a permeability-augmenting agent, histamine. Freshly excised ovine larynges are obtained from a local abattoir. TJ markers are explored via reverse transcriptase polymerase chain reaction (RT-PCR). Paracellular permeabilities are measured in an Ussing system. The gene expression of both TJ markers is detected in native ovine vocal fold epithelium. Luminal histamine treatment significantly decreases transepithelial resistance (TER) (N = 72, p<0.01) and increases penetration of protein tracer (N = 35, p<0.001), respectively, in a time-, and dose-dependent fashion. The present study demonstrates that histamine compromises TJ-related paracellular barrier across vocal fold epithelium. The detection of TJ markers indicates the existence of typical TJ components in non-keratinized, stratified vocal fold epithelium. The responsiveness of paracellular permeabilities to histamine would highlight the functional significance of this TJ-equivalent system to the electrophysiological homeostasis, which, in turn, regulates the vocal fold superficial hydration.
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Affiliation(s)
- Qianru Zhang
- Experimental Center of Functional Subjects, College of Basic Science, China Medical University, Shenyang, Liaoning, China.
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Welham NV, Yamashita M, Choi SH, Ling C. Cross-sample validation provides enhanced proteome coverage in rat vocal fold mucosa. PLoS One 2011; 6:e17754. [PMID: 21423617 PMCID: PMC3057991 DOI: 10.1371/journal.pone.0017754] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 02/09/2011] [Indexed: 01/20/2023] Open
Abstract
The vocal fold mucosa is a biomechanically unique tissue comprised of a densely cellular epithelium, superficial to an extracellular matrix (ECM)-rich lamina propria. Such ECM-rich tissues are challenging to analyze using proteomic assays, primarily due to extensive crosslinking and glycosylation of the majority of high Mr ECM proteins. In this study, we implemented an LC-MS/MS-based strategy to characterize the rat vocal fold mucosa proteome. Our sample preparation protocol successfully solubilized both proteins and certain high Mr glycoconjugates and resulted in the identification of hundreds of mucosal proteins. A straightforward approach to the treatment of protein identifications attributed to single peptide hits allowed the retention of potentially important low abundance identifications (validated by a cross-sample match and de novo interpretation of relevant spectra) while still eliminating potentially spurious identifications (global single peptide hits with no cross-sample match). The resulting vocal fold mucosa proteome was characterized by a wide range of cellular and extracellular proteins spanning 12 functional categories.
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Affiliation(s)
- Nathan V Welham
- Department of Surgery, Division of Otolaryngology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America.
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Tanner K, Roy N, Merrill RM, Muntz F, Houtz DR, Sauder C, Elstad M, Wright-Costa J. Nebulized isotonic saline versus water following a laryngeal desiccation challenge in classically trained sopranos. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2010; 53:1555-1566. [PMID: 20699338 DOI: 10.1044/1092-4388(2010/09-0249)] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
PURPOSE To examine the effects of nebulized isotonic saline (IS) versus sterile water (SW) on self-perceived phonatory effort (PPE) and phonation threshold pressure (PTP) following a surface laryngeal dehydration challenge in classically trained sopranos. METHOD In a double-blind, within-subject crossover design, 34 sopranos breathed dry air (relative humidity < 1%) transorally for 15 min and then nebulized 3 mL of IS or SW, or experienced a no-treatment control condition over 3 consecutive weeks. PPE and PTP were measured every 15 min from baseline through 2 hr postdesiccation. RESULTS PPE increased significantly following the laryngeal desiccation challenge in all 3 treatment conditions (p < .01). After nebulization, PPE returned to baseline for the IS condition only. For the SW and control conditions, PPE remained above baseline during the 2 hr after desiccation. No statistically significant changes in PTP following laryngeal desiccation were observed, although values for the IS condition remained below baseline for nearly 2 hr after nebulization. PPE and PTP were not significantly correlated. CONCLUSIONS Following a laryngeal surface dehydration challenge, classically trained sopranos reported increased vocal effort that persisted for at least 2 hr. Compared with SW, nebulized IS showed promise as an effective way to remediate the adverse, self-perceived effects of laryngeal desiccation.
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Affiliation(s)
- Kristine Tanner
- Department of Communication Sciences and Disorders, Division of Otolaryngology-Head & Neck Surgery, The University of Utah, Salt Lake City, UT 84112, USA.
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Erickson E, Sivasankar M. Simulated reflux decreases vocal fold epithelial barrier resistance. Laryngoscope 2010; 120:1569-75. [PMID: 20564752 DOI: 10.1002/lary.20983] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVES/HYPOTHESIS The vocal fold epithelium provides a barrier to the entry of inhaled and systemic challenges. However, the location of the epithelium makes it vulnerable to damage. Past research suggests, but does not directly demonstrate, that exposure to gastric reflux adversely affects the function of the epithelial barrier. Understanding the nature of reflux-induced epithelial barrier dysfunction is necessary to better recognize the mechanisms for vocal fold susceptibility to this disease. Therefore, we examined the effects of physiologically relevant reflux challenges on vocal fold transepithelial resistance and gross epithelial and subepithelial appearance. STUDY DESIGN Ex vivo, mixed design with between-group and repeated-measures analyses. METHODS Healthy, native porcine vocal folds (N = 52) were exposed to physiologically relevant acidic pepsin, acid-only, or pepsin-only challenges and examined with electrophysiology and light microscopy. For all challenges, vocal folds exposed to a neutral pH served as control. RESULTS Acidic pepsin and acid-only challenges, but not pepsin-only or control challenges significantly reduced transepithelial resistance within 30 minutes. Reductions in transepithelial resistance were irreversible. Challenge exposure produced minimal gross changes in vocal fold epithelial or subepithelial appearance as evidenced by light microscopy. CONCLUSIONS These findings demonstrate that acidic environments characteristic of gastric reflux compromise epithelial barrier function without gross structural changes. In healthy, native vocal folds, reductions in transepithelial resistance could reflect reflux-related epithelial disruption. These results might guide the development of pharmacologic and therapeutic recommendations for patients with reflux, such as continued acid-suppression therapy and patient antireflux behavioral education.
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Affiliation(s)
- Elizabeth Erickson
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana, USA
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Ling C, Yamashita M, Waselchuk EA, Raasch JL, Bless DM, Welham NV. Alteration in cellular morphology, density and distribution in rat vocal fold mucosa following injury. Wound Repair Regen 2009; 18:89-97. [PMID: 20002898 DOI: 10.1111/j.1524-475x.2009.00550.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The vocal fold mucosa plays an important role in voice production. Its cellular composition and density frequently change under various pathological conditions, often contributing to altered extracellular matrix production, tissue viscoelasticity, and voice quality. In this study, cellular changes in the rat mucosa following a unilateral stripping injury were investigated and analyzed semi-quantitatively. Distinctive and sequential changes in cellular morphology, composition, and density were observed in the mucosa post-injury. Cellular recruitment was a major event during the early stage of injury and reached its peak level by day 5 post-injury. Several types of cells, including neutrophil-like cells, epithelial cells, and fibroblast-like cells, were sequentially recruited. The sequential emergence of reactive cell populations following injury and subsequent reconstruction of the mucosa suggests their involvement in vocal fold tissue repair and scar formation processes.
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Affiliation(s)
- Changying Ling
- Department of Surgery, Division of Otolaryngology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792, USA
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Current Opinion in Otolaryngology & Head & Neck Surgery. Current world literature. Curr Opin Otolaryngol Head Neck Surg 2009; 17:494-8. [PMID: 19907224 DOI: 10.1097/moo.0b013e32833385d7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Leydon C, Sivasankar M, Falciglia DL, Atkins C, Fisher KV. Vocal fold surface hydration: a review. J Voice 2009; 23:658-65. [PMID: 19111440 PMCID: PMC2810851 DOI: 10.1016/j.jvoice.2008.03.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 03/26/2008] [Indexed: 01/20/2023]
Abstract
Vocal fold surface liquid homeostasis contributes to optimal vocal physiology. In this paper we review emerging evidence that vocal fold surface liquid is maintained in part by salt and water fluxes across the epithelium. Based on recent immunolocalization and electrophysiological findings, we describe a transcellular pathway as one mechanism for regulating superficial vocal fold hydration. We propose that the pathway includes the sodium-potassium pump, sodium-potassium-chloride cotransporter, epithelial sodium channels, cystic fibrosis transmembrane regulator chloride channels, and aquaporin water channels. By integrating knowledge of the regulating mechanisms underlying ion and fluid transport with observations from hydration challenges and treatments using in vitro and in vivo studies, we provide a theoretical basis for understanding how environmental and behavioral challenges and clinical interventions may modify vocal fold surface liquid composition. We present converging evidence that clinical protocols directed at facilitating vocal fold epithelial ion and fluid transport may benefit healthy speakers, those with voice disorders, and those at risk for voice disorders.
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Affiliation(s)
- Ciara Leydon
- Department of Speech Communication Arts and Sciences, Brooklyn College of The City University of New York, New York 12110, USA.
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Leydon C, Fisher KV, Lodewyck-Falciglia D. The cystic fibrosis transmembrane conductance regulator and chloride-dependent ion fluxes of ovine vocal fold epithelium. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2009; 52:745-754. [PMID: 18806217 DOI: 10.1044/1092-4388(2008/07-0192)] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
PURPOSE Ion-driven transepithelial water fluxes participate in maintaining superficial vocal fold hydration, which is necessary for normal voice production. The authors hypothesized that Cl(-) channels are present in vocal fold epithelial cells and that transepithelial Cl(-) fluxes can be manipulated pharmacologically. METHOD Immunohistochemical assays were used to identify cystic fibrosis transmembrane regulator Cl(-) channels in ovine vocal fold mucosae (n = 2). Electrophysiological responses of vocal fold mucosae (n = 80) to Cl(-) channel inhibitors and secretagogues were evaluated in an ovine model using a randomized controlled experimental design. RESULTS Cystic fibrosis transmembrane regulator channels were localized to the plasma membranes of epithelial cells. The Cl(-) transport inhibitor, diphenylamine-2-carboxylate, elicited a 30% decrease in mean short-circuit current (I(sc); n = 10). The secretagogue, isobutylmethylxanthine, yielded a 31.7% increase in mean I(sc) (n = 10). Another secretagogue, uridine triphosphate, elicited a 48.8% immediate and 17.3% sustained increase in mean I(sc) (n = 10). No sustained increases occurred following application of secretagogues to mucosae bathed in a low Cl(-) environment (n = 10), suggesting that responses were Cl(-) dependent. CONCLUSIONS The authors provide structural and functional evidence for the presence of a transepithelial pathway for Cl(-) fluxes. Pharmacological manipulation of this pathway may offer a mechanism for maintaining superficial vocal fold hydration.
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Affiliation(s)
- Ciara Leydon
- Department of Speech Communication Arts and Sciences, Brooklyn College of The City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA.
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