Faculty Bibliography

BACKGROUND: Radiation therapy (RT) to the head and neck often results in damage to the vocal folds (VF) and surrounding structures. Characterization and treatment of these sequelae is limited, likely due to the lack of experimental models. METHODS: Larynges from rats exposed to 2 fractionation schedules (40 Gy total) were analyzed histologically. In vitro, reactive oxygen species (ROS) synthesis, and transcription of select genes associated with ROS, inflammation, and fibrosis were examined in VF fibroblasts after single-dose radiation. RESULTS: Although radiation-induced histologic alterations are made to VF architecture, 1 fractionation schedule was accompanied by significant morbidity and mortality. In vitro, radiation increased ROS synthesis and inflammatory and profibrotic gene expression. CONCLUSION: Our data suggest that hyperfractionated RT is more tolerable. Utilizing this model, RT-induced histologic aberrations are made to the VF mucosa. In addition, a relationship between radiation, ROS, and inflammatory and fibrotic gene expression was observed in vitro

To review existing patient reported outcomes measures (PROMs) used in dysphonic populations to assess the procedures used in their development and the extent to which these meet current development standards for content generation and psychometric evaluation. The study is a systematic review. A systematic review of Medline, Cumulative Index to Nursing & Allied Health, and Health and Psychosocial Instruments databases was completed using voice, quality of life, and PROMs as keywords. We identified all patient or parent-reported questionnaires measuring quality of life associated with voice disorders from the review findings. Questionnaires were appraised for adherence to international guidelines for the development and evaluation of PROMs as outlined by the Scientific Advisory Committee of the Medical Outcome Trust. Nine PROMs fulfilled the inclusion criteria. The quality of these questionnaires was variable with regard to instrument development and none met all of the current, recommended criteria. Of the nine questionnaires, the Voice Symptom Scale underwent the most rigorous development process. Furthermore, many instruments have been augmented to allow for proxy administration, failing to address quality of life-related issues specific to the target population. Instrument development is often overlooked when attempting to quantify patient reported outcomes in dysphonic patients. Careful instrument development procedures are required to ensure that PROMs are valid, reliable, and responsive. Our review suggests that the deficits in psychometric properties of the current voice-related PROMs may be, at least in part, due to deficits in the development process. Furthermore, these data suggest the potential utility of a novel PROM adhering to rigorous international standards to better ensure that clinicians appreciate the variables most relevant to patients with voice disorders and address some of the psychometric shortcomings of the currently used questionnaires

We present the unique opportunity to correlate videostroboscopic findings with histologic examination. An immunocompromised patient with hoarseness because of ulcerative lesions of both vocal folds of uncertain cause died within a few weeks of initial presentation, and the larynx was donated for postmortem examination. Relevant history, as well as endoscopic and histopathologic findings, is presented

OBJECTIVE: Dehydration challenges can increase the chemical composition of surface fluid overlying vocal fold epithelia (hypertonic surface fluid). The vocal fold epithelium is posited to act as a barrier, shielding the lamina propria from perturbations in the airway lumen. However, the effects of hypertonic surface fluid on the barrier functions of vocal fold epithelia have not been quantified. We, therefore, sought to investigate whether hypertonic surface fluid compromises epithelial barrier function. We examined the effects of hypertonic surface fluid on vocal fold epithelial resistance, paracellular pathway morphology, and tight junction protein integrity. STUDY DESIGN: Ex vivo, between group design. SETTING: Laboratory. METHODS: Porcine vocal folds (n = 24) were exposed to hypertonic or isotonic challenge and examined by electrophysiology, transmission electron microscopy, and Western blot analyses. RESULTS: Hypertonic, but not isotonic, challenge significantly reduced transepithelial resistance. This decrease in resistance was observed immediately after the challenge and was consistent with the appearance of dilated paracellular pathway morphology. However, hypertonic challenge did not alter protein levels of occludin, zona occludens-1, E-cadherin, or beta-catenin. CONCLUSION: Hypertonic surface fluid alters epithelial barrier function in the vocal folds. Specifically, exposure to hypertonic challenges increases epithelial permeability. Given the important role of the vocal fold epithelium in shielding the underlying mucosa from inhaled pathogens and pollutants, our data provide the impetus for future studies on pharmacological treatments aimed at restoring the hydration level and chemical composition of vocal fold surface fluid

OBJECTIVES/HYPOTHESIS: The potassium titanyl phosphate (KTP) laser is emerging as a potentially effective treatment for various vocal fold pathologies. To date, the precise mechanism(s) of action of this wavelength on the layered microarchitecture of the vocal fold remains unknown. The purpose of this study is to develop an in vivo model for the use of the KTP laser in the rat vocal fold and to characterize the potential of this model for future studies. STUDY DESIGN: In vivo survival surgery. METHODS: A model for videoendoscopic visualization and injury to the rat vocal fold was established using a microlaryngoscope and rigid telescope. Unilateral vocal fold injury was induced with the KTP laser at 10 Watts (W) 20 milliseconds (ms) pulse width. Animals were euthanized at 1 day post-treatment. Larynges were subjected to gross visual analysis and histological analyses via hematoxylin and eosin and trichrome staining. RESULTS: Consistent endoscopic visualization and injury was obtained without significant operative morbidity or mortality. The KTP laser caused superficial blanching and minor edema in the vocal fold, which resolved grossly by 24 hours postinjury. A modest inflammatory cell infiltrate was observed 1 day following injury. However, no remarkable alterations to the vocal fold microarchitecture were observed in the acute period. CONCLUSIONS: We propose that this novel model simulates the clinical scenario of laser use for the vocal folds. Use of this model will allow us to further characterize effects, mechanisms, and therapeutic efficacy of this wavelength

OBJECTIVE/HYPOTHESIS: Oxidative damage mediates the lower airway response to cigarette smoke (CS). In the vocal folds, the tissue phenotype is both distinct and largely uncharacterized. We sought to investigate the effects of CS on the oxidative status and fibroblast phenotype in the vocal folds. Specifically, we hypothesized that CS would induce a hypermetabolic fibroblast phenotype and altered oxidative metabolism potentially providing insight into the relationship among CS, Reinke's edema (RE), and malignancy. STUDY DESIGN: In vivo/in vitro. METHODS: Heme oxygenase (HO)-1 gene expression was examined in human tissue. In vitro, the effects of cigarette smoke condensate (CSC) on HO-1 gene expression and secretion was assayed. In addition, CS-mediated intracellular reactive oxygen species synthesis was quantified, and compared to the response in pulmonary fibroblasts (HFL). We then examined the effects of CSC on migration and proliferation in human vocal fold fibroblasts (HVOX). RESULTS:: HO-1 expression was approximately 4-fold higher in RE samples versus vocal fold polyps. CSC induced HO-1 gene expression and secretion in a time- and dose-dependent fashion in vitro. CSC also increased intracellular ROS in both HVOX and HFL. CSC decreased HVOX proliferation and migration in a dose-dependent manner. CONCLUSIONS: These data suggest that the fibroblast phenotype is influenced by smoke. Our data suggest that the antioxidant response in the vocal fold tissue may be one mechanism of chemoprotection, a putative explanation for the observation that RE rarely transforms to malignancy. In addition, CSC does not appear to induce a hypermetabolic fibroblast phenotype as expected

The objectives of this study are to describe central nervous system modulation associated with voice improvement following Type I thyroplasty in a patient with glottic insufficiency secondary to unilateral vocal fold paralysis. Serial functional magnetic resonance imaging scans were performed before as well as one and six months after thyroplasty. Paradigms consisting of four voice production tasks and a motor control task were completed. Volumes of activation within regions activated during each task were measured. Acoustic and aerodynamic measures were also obtained. A widespread network of neural activations was shown for all tasks. Differences in volumes of activation 1-month postsurgery positively correlated with acoustic and aerodynamic improvements. Sixth months following medialization, lesser volumes of activation were observed in all regions. Prior to this session, however, the patient's mediastinal disease progressed, leading to a significant deterioration in voice. Functional differences between patient brain maps yield new information about the central nervous system's ability to reorganize sensorimotor representations associated with voice improvement following Type I thyroplasty in a patient with glottic insufficiency secondary to unilateral vocal fold paralysis (UVFP)

OBJECTIVES: We studied the effect of transforming growth factor (TGF)-beta on immortalized human vocal fold fibroblasts. METHODS: Normal human vocal fold fibroblasts were subjected to sequential lentiviral transduction with genes for human telomerase (hTERT) and SV40 large T antigen in order to produce an 'immortalized' cell line of normal phenotype. After confirmation of vocal fold fibroblast transfection, these cells, referred to as HVOX, were treated with various concentrations of exogenous TGF-beta1 and assayed for collagen secretion, migration, and proliferation. In addition, components of the TGF-beta signaling pathway were examined in this cell line. RESULTS: TGF-beta stimulated collagen secretion and migration without altering proliferation of HVOX. HVOX constitutively expressed type I and II TGF-beta receptors, as well as messenger RNA for the Smad signaling proteins and for all TGF-beta isoforms. Exogenous TGF-beta1 induced temporally dependent alterations in Smad2 and Smad3 gene expression. TGF-beta increased Smad7 expression at both 4 and 24 hours. Prolonged exposure to TGF-beta decreased TGF-beta1 gene expression. CONCLUSIONS: Insight into the underlying pathophysiology of vocal fold fibrosis is likely to yield improved therapeutic strategies to mitigate vocal fold scarring. Our data suggest that TGF-beta signaling may be both paracrine and autocrine in this vocal fold fibroblast cell line, and we therefore propose that TGF-beta may be a reasonable target for therapies to prevent and/or treat vocal fold fibrosis, given its putative role in both acute and chronic vocal fold injury, as well as its effects on vocal fold fibroblasts

Voice production involves precise, coordinated movements of the intrinsic and extrinsic laryngeal musculature. A component of normal voice production is the modification of pitch. The underlying neural networks associated with these complex processes remains poorly characterized. However, several investigators are currently utilizing neuroimaging techniques to more clearly delineate these networks associated with phonation. The current study sought to identify the central cortical mechanism(s) associated with pitch variation during voice production using event-related functional MRI (fMRI). A single-trial design was employed consisting of three voice production tasks (low, comfortable, and high pitch) to contrast brain activity during the generation of varying frequencies. For whole brain analysis, volumes of activation within regions activated during each task were measured. Bilateral activations were shown in the cerebellum, superior temporal gyrus, insula, precentral gyrus, postcentral gyrus, inferior parietal lobe, and post-cingulate gyrus. In the left hemisphere, activations in the medial and middle frontal gyri were also observed. Regions active during high pitch production when compared to comfortable pitch were evident in the bilateral cerebellum, left inferior frontal gyrus, left cingulate gyrus, and left posterior cingulate. During low pitch generation, activations were present in the inferior frontal gyrus, insula, putamen, and cingulate gyrus in the left hemisphere. The inferior frontal gyrus in the right hemisphere produced greater activity than the area of the left hemisphere during high and low pitch generation. These results suggest that a single-trial design is sensitive enough to begin to delineate a widespread network of activations in both hemispheres associated with vocal pitch variation