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Vocal fold (VF) fibrosis is a major cause of intractable voice-related disability and reduced quality of life. Excision of fibrotic regions is suboptimal and associated with scar recurrence and/or further iatrogenic damage. Non-surgical interventions are limited, putatively related to limited insight regarding biochemical events underlying fibrosis, and downstream, the lack of therapeutic targets. YAP/TAZ integrates diverse cell signaling events and interacts with signaling pathways related to fibrosis, including the TGF-β/SMAD pathway. We investigated the expression of YAP/TAZ following vocal fold injury in vivo as well as the effects of TGF-β1 on YAP/TAZ activity in human vocal fold fibroblasts, fibroblast-myofibroblast transition, and TGF-β/SMAD signaling. Iatrogenic injury increased nuclear localization of YAP and TAZ in fibrotic rat vocal folds. In vitro, TGF-β1 activated YAP and TAZ in human VF fibroblasts, and inhibition of YAP/TAZ reversed TGF-β1-stimulated fibroplastic gene upregulation. Additionally, TGF-β1 induced localization of YAP and TAZ in close proximity to SMAD2/3, and nuclear accumulation of SMAD2/3 was inhibited by a YAP/TAZ inhibitor. Collectively, YAP and TAZ were synergistically activated with the TGF-β/SMAD pathway, and likely essential for the fibroplastic phenotypic shift in VF fibroblasts. Based on these data, YAP/TAZ may evolve as an attractive therapeutic target for VF fibrosis.

Background: Laryngopharyngeal reflux (LPR) can induce laryngeal hyper-responsiveness, a unifying feature underlying chronic cough and vocal cord dysfunction. The diagnosis of LPR currently relies on invasive oesophageal pH impedance testing. We compared symptoms, laryngeal signs and salivary pepsin as potential diagnostic methods for identifying LPR in patients with upper airway symptoms., Methods: Symptoms were assessed using the Reflux Symptom Index (RSI) and signs of laryngeal inflammation quantified using the Reflux Finding Score (RFS) during laryngoscopy. Saliva samples were analysed for the presence of pepsin. A sub-group of patients with severe symptoms and signs of LPR were investigated with oesophageal pH monitoring and impedance study., Results: Seventy eight patients with chronic cough and/or suspected vocal cord dysfunction were recruited, mean (SD) age, 54.6 (15.6) years. The majority (87%) had significant symptoms of reflux (RSI>13). There were clinical signs of LPR (RFS>7) in 51% of cases. Pepsin was detected in the saliva of 63% of subjects and 78% of those with a high RFS. Salivary pepsin had a sensitivity of 78% and specificity of 53% for predicting a high RFS. There was a correlation between the RSI and RFS (r = 0.51, p < 0.001) and between the severity of laryngeal inflammation and the concentration of pepsin (r = 0.28, p = 0.01). All cases investigated with pH-impedance study had objective evidence of proximal reflux., Conclusion: Salivary pepsin may be used as a screening adjunct to supplement the RFS in the clinical workup of patients with extra-oesophageal symptoms and upper respiratory tract presentations of reflux., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objective: Corticosteroids may be beneficial in treating vocal fold scarring. Current drug delivery methods do not permit controlled corticosteroid release. Here we investigate the effects of poly-lactic-co-glycolic acid (PLGA) microparticles loaded with the corticosteroid dexamethasone in reducing collagen synthesis and inflammation in vocal fold fibroblasts treated with and without TGF-β1., Study Design: Experimental, in vitro study., Methods: PLGA microparticles of differing molecular weight and terminating moieties were synthesized using a hydrogel template method. The release of dexamethasone was characterized from these microparticles over 4 days. Based on the release studies, ester-terminated low molecular weight PLGA microparticles were loaded with dexamethasone and applied to TGF-β1 treated vocal fold fibroblasts for 4 days. Quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assays (ELISAs) were used to assess the effects of released dexamethasone on collagen synthesis and inflammatory mediators., Results: COL3A1 and COL1A2 were significantly down-regulated after exposure to ester-terminated low molecular weight PLGA microparticles loaded with dexamethasone. The loaded microparticles also reduced interleukin-6 synthesis., Conclusion: These data show promise in using a PLGA microparticle-based delivery system to control dexamethasone release over 4 days. Our findings lay the groundwork for developing more effective treatments for vocal fold scarring., (© The Author(s) 2015.)

Objectives/hypothesis: Vocal fold scarring is one of the most challenging laryngeal disorders to treat. Hyaluronic acid (HA) is the main component of lamina propria, and it plays an important role in proper vocal fold vibration and is also thought to be important in fetal wound healing without scarring. Although several animal models of vocal fold scarring have been reported, little is known about the way in which HA is maintained in vocal folds. The purpose of this study was to clarify the homeostasis of HA by examining the expression of hyaluronan synthase (Has) and hyaluronidase (Hyal), which produce and digest HA, respectively., Study Design: Experimental prospective animal study., Methods: Vocal fold stripping was performed on 38 Sprague-Dawley rats. Vocal fold tissue was collected at five time points (3 days-2 months). Expression of HA was examined by immunohistochemistry, and messenger RNA (mRNA) expression of Has and Hyal was examined by real-time polymerase chain reaction and in-situ hybridization., Results: In scarred vocal folds, expression of Has1 and Has2 increased at day 3 together with expression of HA and returned to normal at 2 weeks. At 2 months, Has3 and Hyal3 mRNA showed higher expressions than normal., Conclusions: Expression patterns of Has and Hyal genes differed between normal, acute-scarred, and chronic-scarred vocal folds, indicating the distinct roles of each enzyme in maintaining HA. Continuous upregulation of Has genes in the acute phase may be necessary to achieve scarless healing of vocal folds., (Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives/hypothesis: Reactive oxygen species (ROS) are associated with aging. Astaxanthin (AST) is a strong antioxidant and has been reported to prevent various ROS-induced diseases. In the current study, we investigated the effect of AST on age-associated histological and mRNA changes of vocal folds., Study Design: Prospective animal experiment with control., Methods: Six-month-old Sprague-Dawley rats were fed on a normal powder diet with 0.01% (w/w) AST (aged AST-treated group) or without AST (aged sham-treated group). After 12 months of feeding, the larynges were harvested for histology, immunohistochemical detection of 4-hydroxy-2-nonenal (4-HNE), and quantitative real-time polymerase chain reaction for basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF). Thirteen-week-old rats were used as a young control group (young group)., Results: The expression of 4-HNE, an oxidative stress marker, significantly increased in the two aged groups compared with the young group. Histological examination showed that the deposition of hyaluronic acid in the lamina propria (LP) was significantly reduced in the aged sham-treated group compared with the young group, but no significant difference was observed between the aged AST-treated group and the young group. There were no significant differences in the mRNA expression of bFGF and HGF between the aged AST-treated group and the young group, although the expression of these genes was significantly reduced in the aged sham-treated group as compared with the young group., Conclusions: These results suggest that AST has the potential to attenuate age-associated changes of vocal folds., (© 2014 The American Laryngological, Rhinological and Otological Society, Inc.)