Differential gene expression profiling of vocal fold polyps and Reinke's edema by complementary DNA microarray

Mechanotransduction in the Vocal Fold Microenvironment: A Narrative Review

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.

Comparing Effects of Short- and Long-Term Exposure of Cigarette Smoke Extract on Human Vocal Fold Fibroblasts

OBJECTIVES

To explore the effects of short- and long-term cigarette smoke extract (CSE) stimulation on the expression of extracellular matrix (ECM) components and inflammatory cytokines in an in vitro model for studying Reinke's edema using human vocal fold fibroblasts (hVFF).

STUDY DESIGN

Experimental pilot study using intervention with CSE in vitro.

METHODS

Immortalized hVFF were pretreated with 5% CSE or control medium over a period of 2 or 8 weeks, followed by a final 3-day incubation time. We evaluated cell proliferation and examined gene and protein expression of control- and CSE-treated cells using quantitative polymerase chain reaction, Western Blot and enzyme linked immunosorbent assay.

RESULTS

Cell numbers of CSE-treated hVFF strongly decreased after 8 weeks and limited the overall duration of the experiment. We observed significant upregulations in gene expression and protein levels of inflammatory markers (cyclooxygenase COX1, COX2) and ECM components (decorin, matrix metalloproteinase 1, transglutaminase 2, gremlin 2) induced by CSE after 2 and 8 weeks. Interleukin 1 receptor 1, prostaglandin I2 synthase, collagen- and hyaluronan-related gene expression showed minor upregulations. The majority of the observed genes were similarly regulated at both time points. However, the CSE-induced mRNA level of COX1 was ablated after 8 weeks.

CONCLUSION

Long-term treatment did not yield results significantly different from the short-term protocol. Therefore, we propose that prolonged CSE exposure is not superior to short-term settings, which save both time and materials.

DNA rare copy number alterations in Reinke’s Edema

INTRODUCTION

Reinke's Edema (RE) is a laryngeal lesion related to excessive tobacco smoking, voice overuse, and laryngopharyngeal reflux. Although the risk of malignancy has been considered low in literature, RE is classified among precancerous lesions.

OBJECTIVES

We investigated DNA Copy Number Alterations (CNAs) in specimens of RE and its potential association with malignant progression.

METHODS

We used array-based comparative genomic hybridization (aCGH, Agilent 4 × 180 K platform) to study eight RE cases. All patients were heavy tobacco users for at least 30 years, and none of them progressed to cancer in the follow-up (>8 years). Two RE presented mild dysplasia, one moderate dysplasia, and no histological alterations were found in the remaining five cases. CNAs were compared with the Database of Genomic Variants (DGV) and genes mapped on altered regions had their functions annotated.

RESULTS

Six of eight patients showed different rare copy number alterations on chromosomes 2q37.3, 4q13.1, 4q13.3, 7q11.22, 10p14, and 13q34. A gain of the whole chromosome 8 were detected in one case. Of interest, four of eight RE cases showed copy number imbalances involving genes previously described in several tumor types (RASA3, COL6A3, LINC00707, LINP1, SMR3A, and SMR3B).

CONCLUSION

The genomic imbalances herein found in RE have the potential to contribute to the phenotype but with limited or no risk of cancer. A long-term follow-up in a large series of patients could clarify the mechanisms involved in the malignant progression of RE.

LEVEL OF EVIDENCE: 4

Vocal Fold Fibroblasts in Reinke's Edema Show Alterations Involved in Extracellular Matrix Production, Cytokine Response and Cell Cycle Control

The voice disorder Reinke’s edema (RE) is a smoking- and voice-abuse associated benign lesion of the vocal folds, defined by an edema of the Reinke’s space, accompanied by pathological microvasculature changes and immune cell infiltration. Vocal fold fibroblasts (VFF) are the main cell type of the lamina propria and play a key role in the disease progression. Current therapy is restricted to symptomatic treatment. Hence, there is an urgent need for a better understanding of the molecular causes of the disease. In the present study, we investigated differential expression profiles of RE and control VFF by means of RNA sequencing. In addition, fast gene set enrichment analysis (FGSEA) was performed in order to obtain involved biological processes, mRNA and protein levels of targets of interest were further evaluated. We identified 74 differentially regulated genes in total, 19 of which were upregulated and 55 downregulated. Differential expression analysis and FGSEA revealed upregulated genes and pathways involved in extracellular matrix (ECM) remodeling, inflammation and fibrosis. Downregulated genes and pathways were involved in ECM degradation, cell cycle control and proliferation. The current study addressed for the first time a direct comparison of VFF from RE to control and evaluated immediate functional consequences.

High-resolution magnetic resonance and mass spectrometry imaging of the human larynx

High-resolution, noninvasive and nondestructive imaging of the subepithelial structures of the larynx would enhance microanatomic tissue assessment and clinical decision making; similarly, in situ molecular profiling of laryngeal tissue would enhance biomarker discovery and pathology readout. Towards these goals, we assessed the capabilities of high-resolution magnetic resonance imaging (MRI) and matrix-assisted laser desorption/ionisation-mass spectrometry (MALDI-MS) imaging of rarely reported paediatric and adult cadaveric larynges that contained pathologies. The donors were a 13-month-old male, a 10-year-old female with an infraglottic mucus retention cyst and a 74-year-old female with advanced polypoid degeneration and a mucus retention cyst. MR and molecular imaging data were corroborated using whole-organ histology. Our MR protocols imaged the larynges at 45-117 μm² in-plane resolution and capably resolved microanatomic structures that have not been previously reported radiographically-such as the vocal fold superficial lamina propria, vocal ligament and macula flavae; age-related tissue features-such as intramuscular fat deposition and cartilage ossification; and the lesions. Diffusion tensor imaging characterised differences in water diffusivity, primary tissue fibre orientation, and fractional anisotropy between the intrinsic laryngeal muscles, mucosae and lesions. MALDI-MS imaging revealed peptide signatures and putative protein assignments for the polypoid degeneration lesion and the N-glycan constituents of one mucus retention cyst. These imaging approaches have immediate application in experimental research and, with ongoing technology development, potential for future clinical application.

[Molecular laryngology : A new chapter in the understanding of laryngeal diseases]

BACKGROUND

Despite considerable advances in laryngological research, there is still a plethora of (benign) vocal fold pathologies that cannot be treated causally. This is due to the limited accessibility and sensitive microarchitecture of the vocal folds, which cannot be investigated at a cellular level. Consequently, current pathophysiological knowledge is frequently based on macroscopic findings. The impact of interventions is mainly evaluated endoscopically or via indirect diagnostic methods.

OBJECTIVE

The aim of this article is to discuss state-of-the-art biotechnological methods used in laryngological research, illustrated by practical examples.

RESULTS

In recent years, animal and in vitro experiments have significantly contributed to a continuous expansion of knowledge in this field, particularly regarding vocal fold inflammation and scar formation. Vocal fold fibroblasts, the most important cellular component of the lamina propria, can be accredited a central role in these processes.

CONCLUSION

Our knowledge regarding macroanatomy and macropathophysiology of several pathologies has increased considerably in recent years. In vitro trials have shown, e.g., that vocal fold fibroblasts in an inflammatory setting secrete less profibrotic and proinflammatory cytokines when exposed to vibration. Early vocal exercises after surgical interventions on the vocal folds may therefore promote better wound healing and consequently improved phonation. Research in molecular laryngology should create a solid basis of knowledge for subsequent clinical studies.

Proteomic Analysis of Vocal Fold Fibroblasts Exposed to Cigarette Smoke Extract: Exploring the Pathophysiology of Reinke's Edema

Reinke's edema is a smoking-associated, benign, mostly bilateral lesion of the vocal folds leading to difficulties in breathing and voice problems. Pronounced histological changes such as damaged microvessels or immune cell infiltration have been described in the vocal fold connective tissue, the lamina propria Thus, vocal fold fibroblasts, the main cell type of the lamina propria, have been postulated to play a critical role in disease mediation. Yet information about the pathophysiology is still scarce and treatment is only surgical, i.e. symptomatic. To explore the pathophysiology of Reinke's edema, we exposed near-primary human vocal fold fibroblasts to medium conditioned with cigarette smoke extract for 24 h as well as 4 days followed by quantitative mass spectrometry.Proteomic analyses after 24 h revealed that cigarette smoke increased proteins previously described to be involved in oxidative stress responses in other contexts. Correspondingly, gene sets linked to metabolism of xenobiotics and reactive oxygen species were significantly enriched among cigarette smoke-induced proteins. Among the proteins most downregulated by cigarette smoke, we identified fibrillar collagens COL1A1 and COL1A2; this reduction was validated by complementary methods. Further, we found a significant increase of UDP-glucose 6-dehydrogenase, generating a building block for biosynthesis of hyaluronan, another crucial component of the vocal fold lamina propria In line with this result, hyaluronan levels were significantly increased because of cigarette smoke exposure. Long term treatment of 4 days did not lead to significant changes.The current findings corroborate previous studies but also reveal new insights in possible disease mechanisms of Reinke's edema. We postulate that changes in the composition of the vocal folds' extracellular matrix -reduction of collagen fibrils, increase of hyaluronan- may lead to the clinical findings. This might ease the identification of better, disease-specific treatment options.

Reinke's Edema

Reinke's edema (RE) is the polypoid degeneration of one or both vocal folds within Reinke's space. The viscoelastic properties of the mucosal folds are characteristically altered by the expansion of the subepithelial space. Most frequently, patients present with dysphonia, with women being more affected than men. The primary risk factor is tobacco use. Voice overuse and laryngopharyngeal reflux are also considered to be contributory. Although RE shares the same primary risk factor as malignancy, the risk of malignancy is low, and dysplasia is found only in 0% to 3% of cases. Treatment is focused on decrease of risk factors, such as implementation of smoking cessation, voice therapy, and reflux control. Surgical techniques aim to decrease redundant polypoid mucosa in order to improve voice and restore the glottic airway. Recurrence of RE is high.

Tissue specific human fibroblast differential expression based on RNAsequencing analysis

Background

Physical forces, such as mechanical stress, are essential for tissue homeostasis and influence gene expression of cells. In particular, the fibroblast has demonstrated sensitivity to extracellular matrices with assumed adaptation upon various mechanical loads. The purpose of this study was to compare the vocal fold fibroblast genotype, known for its unique mechanically stressful tissue environment, with cellular counterparts at various other anatomic locales to identify differences in functional gene expression profiles.

Results

By using RNA-seq technology, we identified differentially expressed gene programs (DEseq2) among seven normal human fibroblast primary cell lines from healthy cadavers, which included: vocal fold, trachea, lung, abdomen, scalp, upper gingiva, and soft palate. Unsupervised gene expression analysis yielded 6216 genes differentially expressed across all anatomic sites. Hierarchical cluster analysis revealed grouping based on anatomic site origin rather than donor, suggesting global fibroblast phenotype heterogeneity. Sex and age-related effects were negligible. Functional enrichment analyses based on separate post-hoc 2-group comparisons revealed several functional themes within the vocal fold fibroblast related to transcription factors for signaling pathways regulating pluripotency of stem cells and extracellular matrix components such as cell signaling, migration, proliferation, and differentiation potential.

Conclusions

Human fibroblasts display a phenomenon of global topographic differentiation, which is maintained in isolation via in vitro assays. Epigenetic mechanical influences on vocal fold tissue may play a role in uniquely modelling and maintaining the local environmental cellular niche during homeostasis with vocal fold fibroblasts distinctly specialized related to their anatomic positional and developmental origins established during embryogenesis.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5682-5) contains supplementary material, which is available to authorized users.

Mechanotransduction of vocal fold fibroblasts and mesenchymal stromal cells in the context of the vocal fold mechanome

The design of cell-based therapies for vocal fold tissue engineering requires an understanding of how cells adapt to the dynamic mechanical forces found in the larynx. Our objective was to compare mechanotransductive processes in therapeutic cell candidates (mesenchymal stromal cells from adipose tissue and bone marrow, AT-MSC and BM-MSC) to native cells (vocal fold fibroblasts-VFF) in the context of vibratory strain. A bioreactor was used to expose VFF, AT-MSC, and BM-MSC to axial tensile strain and vibration at human physiological levels. Microarray, an empirical Bayes statistical approach, and geneset enrichment analysis were used to identify significant mechanotransductive pathways associated with the three cell types and three mechanical conditions. Two databases (Gene Ontology, Kyoto Encyclopedia of Genes and Genomes) were used for enrichment analyses. VFF shared more mechanotransductive pathways with BM-MSC than with AT-MSC. Gene expression that appeared to distinguish the vibratory strain condition from polystyrene condition for these two cells types related to integrin activation, focal adhesions, and lamellipodia activity, suggesting that vibratory strain may be associated with cytoarchitectural rearrangement, cell reorientation, and extracellular matrix remodeling. In response to vibration and tensile stress, BM-MSC better mimicked VFF mechanotransduction than AT-MSC, providing support for the consideration of BM-MSC as a cell therapy for vocal fold tissue engineering. Future research is needed to better understand the sorts of physical adaptations that are afforded to vocal fold tissue as a result of focal adhesions, integrins, and lamellipodia, and how these adaptations could be exploited for tissue engineering.

Expression of a disintegrin and metalloproteinase-33 protein in vocal fold polyps

BACKGROUND

This study aimed to evaluate the association of a disintegrin and metalloproteinase-33 protein ('ADAM-33') expression in vocal polyp formation and to determine its correlation with clinical characteristics.

METHODS

Medical charts and histological sections of 32 patients diagnosed with vocal polyps who underwent surgery were analysed. Controls were histopathologically normal vocal fold tissues obtained from 36 patients who underwent surgery for laryngeal squamous cell carcinoma. Immunohistochemical staining was performed to detect ADAM-33 expression in epithelial cells, stroma and vessels.

RESULTS

All epithelial, stromal and vascular staining scores were significantly greater in polyp tissue than in controls (p < 0.001). Stromal ADAM-33 staining scores were higher in vocal polyp patients with a symptom duration of less than six months (p < 0.05). Vocal overuse or the presence of reflux symptoms, sinonasal symptoms or allergy did not affect ADAM-33 immunostaining scores (p = 0.05).

CONCLUSION

In this study, ADAM-33 immunostaining was significantly increased in vocal polyps. Therefore, over-expression of this protein may be associated with vocal polyp pathogenesis.

The Protective Role of Autophagy in Human Vocal Fold Fibroblasts under Cigarette Smoke Extract Exposure: A New Insight into the Study of Reinke's Edema

BACKGROUND/AIMS

Reinke's edema (RE), one of the most common benign lesions of the human vocal folds, has been associated with cigarette smoking. We have observed an abundant number of autophagosomes in the cytoplasm of fibroblasts in the lamina propria of human vocal folds under transmission electron microscopy in RE tissue. Thus, we conducted a study about autophagy induced by cigarette smoke extract (CSE) exposure in cultured human vocal fold fibroblasts (hVFFs).

METHODS

Sampled tissues were cultured and exposed to varying levels of CSE. Immunochemistry staining and Western blot analyses were then performed on the cultures.

RESULTS

We demonstrated that CSE significantly promoted intracellular reactive oxygen species accumulation and reduced the viability of hVFFs in a concentration-dependent manner. Both immunocytochemistry and Western blot analysis showed increased expression of the autophagy marker type II-membrane-associated light chain 3 in fibroblasts following 24 h of CSE exposure, indicating the upregulation of autophagy activity. Furthermore, the results demonstrate that the induction of autophagy played a protective role in hVFFs exposed to CSE.

CONCLUSION

Autophagy can be induced by CSE in hVFFs, and it is a protective response of hVFFs to the exposure of CSE. This study provides a new insight into the process involved in the development of RE.

Lipopolysaccharide responsiveness in vocal fold fibroblasts

Background

Vocal fold fibroblast’s (VFF) strategic location in the lamina propria and their ability to respond to external stimuli by producing inflammatory molecules suggest their possible direct involvement in innate immunity. Toll-like receptors (TLRs) are an essential signaling component to this response, as they allow for recognition of various microorganisms, leading to subsequent induction of pro-inflammatory genes. The objective of this study was to elucidate the role of VFF in the host immune response and subsequent influence on inflammatory cytokine secretion.

Methods

VFF derived from polyp, scar, and normal tissue were treated with 5 μg/ml lipopolysaccharide (LPS). TLR1 through 9, CD14, and MD-2 were measured during stable conditions by polymerase chain reaction (PCR). Expression of TLR4 and IL-1R type-1 genes were quantified after 24 hrs LPS stimulation by reverse transcription-PCR. LPS responsiveness was determined by NF-κB nuclear translocation as measured by subunit p65 expression in nucleus with immunocytochemistry. Downstream effects were confirmed with immunoassay measuring IL-8 concentrations in supernatant after 8 hrs.

Results

All VFFs constitutively expressed TLR1 to 6, TLR9, CD14, and MD-2 mRNA. Polyp VFF exhibited significantly higher TLR4 transcript levels (p < 0.001) in comparison to scar and normal VFF. LPS stimulated scar and polyp VFF exhibited increased levels of p65 in the nucleus (p < 0.01) and secreted greater IL-8 protein (p < 0.0001) compared to normal VFF.

Conclusion

VFF constitutively express genes for the receptors essential to the host immune response. Scar and polyp VFF produced greater LPS responsiveness resulting in over-activated inflammatory patterns. These findings support VFF role in the pathogenesis of inflammatory vocal fold disorders and suggests their presence in the wound bed could lead to chronic inflammation.

Characterization and comparison of bacterial communities in benign vocal fold lesions

BACKGROUND

Benign vocal fold lesions, including cysts, nodules, polyps, and Reinke's edema, are common causes of hoarseness and subsequent voice disorders. Given the prevalence of these lesions, disease etiology and pathophysiology remain unclear and their microbiota has not been studied to date secondary to the paucity of available biopsies for investigation. We sought to characterize and compare the bacterial communities in biopsies of cysts, nodules, polyps, and Reinke's edema collected from patients in Germany and Wisconsin. These samples were then compared to the communities found in healthy saliva and throat samples from the Human Microbiome Project (HMP).

RESULTS

454 pyrosequencing of the V3-V5 regions of the 16S rRNA gene revealed five phyla that explained most of the bacterial diversity, including Firmicutes (73.8%), Proteobacteria (12.7%), Bacteroidetes (9.2%), Actinobacteria (2.1%), and Fusobacteria (1.9%). Every lesion sample, regardless of diagnosis, had operational taxonomic units (OTUs) identified as Streptococcus, with a mean abundance of 68.7%. Most of the lesions, 31 out of 44, were indistinguishable in a principal coordinates analysis (PCoA) due to dominance by OTUs phylogenetically similar to Streptococcus pseudopneumoniae. Thirteen lesions not dominated by S. pseudopneumoniae were more similar to HMP throat and saliva samples, though 12 of them contained Pseudomonas, which was not present in any of the HMP samples. Community structure and abundance could not be correlated with lesion diagnosis or any other documented patient factor, including age, sex, or country of origin.

CONCLUSIONS

Dominance by S. pseudopneumoniae could be a factor in disease etiology, as could the presence of Pseudomonas in some samples. Likewise, decreased diversity, as compared to healthy saliva and throat samples, may be associated with disease, similar to disease models in other mucosal sites.

CD34-positive fibroblasts in Reinke's edema

OBJECTIVES/HYPOTHESIS

To elucidate whether and to what extent CD34+ fibroblasts (so-called CD34+ fibrocytes, CD34+ dendritic cells, and CD34+ stromal cells) occur in normal human vocal folds and in Reinke's edema.

STUDY DESIGN

Histological study.

METHODS

Conventional, immunohistochemical, and ultrastructural procedures were performed in histological blocks of 18 selected cases of Reinke's edema (with typical findings including acellular edematous spaces in the subepithelial connective tissue of vocal folds, and disarrangement of elastic, collagen, and reticular fibers). For control purposes, four normal vocal folds were analyzed.

RESULTS

In normal vocal folds, most stromal cells were spindle-shaped CD34+ fibroblasts. In Reinke's edema, increased density and changes in the morphology and size of this subpopulation of fibroblasts were demonstrated in the connective tissue surrounding the edematous spaces, particularly in their borders, where together with some macrophages they formed boundaries, mimicking the walls of distended lymphatic vessels when conventional stains were used. These activated CD34+ fibroblasts acquired a dendritic morphology (with long, moniliform, often bifurcated, overlapping multipolar processes), and their cytoplasmic organelles were increased in number. In addition to CD34, they expressed vimentin, CD10 and CD99, but no α-smooth muscle actin (α-SMA), CD31, CD117, CD68, h-caldesmon, desmin, or S-100 protein.

CONCLUSIONS

CD34+ fibroblasts are a major cell component in the stroma of vocal folds in Reinke's edema, and their activation, with increased density and morphologic changes around the edematous spaces, occurs without immunophenotypic transformation toward myofibroblasts (no expression of α-SMA). The mechanisms by which these cells act in Reinke's edema require further study.

Paracrine potential of fibroblasts exposed to cigarette smoke extract with vascular growth factor induction

OBJECTIVES/HYPOTHESIS

Nicotine, a major constituent of cigarette smoke, can activate the cholinergic anti-inflammatory pathway by binding to α7-nicotinic acetylcholine receptor (α7nAChR) expressed on the surface of certain cells. Here, we ask whether cigarette smoke extract induced different paracrine factors compared to the in vivo regulator of inflammation, tumor necrosis factor-α, in human vocal fold fibroblasts (hVFFs) shown to express low levels of α7nAChR.

STUDY DESIGN

In vitro.

METHODS

α7nAChR was detected by nested polymerase chain reaction and immunohistochemistry. γH2AX, a marker for DNA double-stand breaks, was measured by immunofluorescence. Cigarette smoke extract was prepared in accordance with investigators studying effects of cigarette smoke. hVFFs treated for 3 hours had media replaced for an additional 24 hours. Cytokine, chemokine, and growth factor levels in media were assessed by multiplex analysis.

RESULTS

α7nAChR expression levels decreased with the passage number of fibroblasts. Tumor necrosis factor-α induced a significantly different profile of cytokines, chemokines, and growth factor compared to cigarette smoke extract exposure. Cigarette smoke extract at a concentration not associated with induction of γH2AX nuclear foci significantly increased vascular endothelial growth factor.

CONCLUSIONS

Cigarette smoke extract elicited a response important for regulation of angiogenesis and vascular permeability during inflammation, without evidence of DNA double-stand breaks associated with carcinogenesis. hVFFs are capable of participating in paracrine regulation of pathological blood vessel formation associated with cigarette smoking-related diseases (ie, Reinke edema). These cells express α7nAChR, an essential component of the cholinergic anti-inflammatory pathway regulated by the vagus nerve in certain tissues and a target of therapeutic agents.

Assessment of fine needle aspiration feasibility and specimen adequacy for molecular diagnostics of benign vocal fold lesions

OBJECTIVES/ HYPOTHESIS

The use of molecular testing is becoming more significant for the diagnosis and classification of disease. The application of fine-needle aspiration (FNA) biopsy as the means of sampling lesions in union with molecular testing could be a powerful combination in laryngology. The objectives of this study were to investigate 1) if FNA was feasible to sample benign vocal fold lesions; 2) if FNA samples provided sufficient RNA quality for molecular analysis; and 3) if gene expression of FNA samples matched paired surgical excised specimens.

STUDY DESIGN

Prospective cross-sectional.

METHODS

Fifteen vocal fold specimens were obtained from adult patients undergoing routine surgical removal for benign vocal fold lesions using FNA and surgical excision. Comparisons were made between FNA and excision biopsies for RNA quality. Correlative analysis was completed for RNA expression of nine genes, including decorin (DCN), connective tissue growth factor (CTGF), vascular endothelial growth factor (VEGF), collagen type VI alpha 3 (COL6A3), superoxide dismutase 1 (SOD1), glutathione S-transferase (GST2), collagen type I alpha 2 (COL1A2), ATP binding cassette (ABC), and procollagen I alpha 1 (COL1A1).

RESULTS

FNA and excision samples demonstrated similar RNA quality (P > 0.05). Per gene expression, four out of nine genes were moderately correlated between the paired samples (P < 0.05).

CONCLUSIONS

FNA of the vocal fold lamina propria is technically feasible to perform. Further improvement in the FNA technology is desirable to optimize RNA quality for reliable gene expression analysis.

Vocal fold fibroblasts immunoregulate activated macrophage phenotype

Recent evidence suggests that fibroblasts play a critical role in regulating inflammation during wound healing because they express several inflammatory mediators in response to bacteria. The objective of this study was to analyze the effects of lipopolysaccharide (LPS) on the immunomodulatory properties of vocal fold fibroblasts (VFFs) derived from polyps, scar and normal tissue co-cultured with macrophages, to provide insight into their interactions during the inflammatory process. Fibroblasts were co-cultured with CD14+ monocytes and after 7 days, wells were treated with LPS for 24 and 72 h. Culture supernatants were collected and concentrations of TNF-α, IL-6, IL-8, IL-10, IL-12, IL-1β and MCP-1 were quantified by ELISA. Normal VFF and CD14+ monocultures were used as controls. Twenty-four hours after LPS activation, macrophages co-cultured with polyp VFF had significantly increased expression of TNF-α, IL-1β, IL-12 and IL-10 compared to controls (p<0.0001). In contrast, macrophages co-cultured with scar VFF had significantly lower expression of TNF-α, IL-1β and IL-12 with significantly higher IL-10 compared to control (p<0.0001). After 72 h, macrophages co-cultured with polyp VFF increased expression of TNF-α, IL-1β, IL-10, IL-6, IL-8, MCP-1 and TGF-β (p<0.01) and macrophages co-cultured with scar VFF significantly decreased their expression of IL-1β and IL-12 compared to control (p<0.0001). Scar VFF at both time points produced significantly lower levels of IL-8, MCP-1, IL-6 and TGF-β compared to controls (p<0.05). Based on our findings, VFF and macrophages secrete several inflammatory mediators that modify their diverse functions. Polyp and scar VFF may play a role in regulating abnormal inflammatory responses, which could result in excessive ECM deposition that disrupts the function of the vocal folds.

Fundamental approaches in molecular biology for communication sciences and disorders

PURPOSE

This contemporary tutorial will introduce general principles of molecular biology, common deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein assays and their relevance in the field of communication sciences and disorders.

METHOD

Over the past 2 decades, knowledge of the molecular pathophysiology of human disease has increased at a remarkable pace. Most of this progress can be attributed to concomitant advances in basic molecular biology and, specifically, the development of an ever-expanding armamentarium of technologies for analysis of DNA, RNA, and protein structure and function. Details of these methodologies, their limitations, and examples from the communication sciences and disorders literature are presented. Results/Conclusions The use of molecular biology techniques in the fields of speech, language, and hearing sciences is increasing, facilitating the need for an understanding of molecular biology fundamentals and common experimental assays.

Cigarette smoke and reactive oxygen species metabolism: implications for the pathophysiology of Reinke's edema

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.

Effects of transforming growth factor-beta1 on human vocal fold fibroblasts

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.

At the crossroads: mucosal immunology of the larynx

The larynx sits at the crossroads between gastrointestinal and respiratory tracts. Besides its intrinsic importance in breathing, swallowing and voice production, the larynx is also exposed to unique immunological challenges. Given the propensity of chronic inflammatory conditions such as chronic laryngitis, which affects up to 20% of Western populations, it is surprising that our understanding of the immunology of this organ remains relatively limited. Recent work on the immunological architecture of the laryngeal mucosa, and its changes that result from external challenges and inflammatory conditions, provided valuable insight into the fascinating immunology of this organ. The lessons learnt from these investigations may go beyond devising improved therapy for chronic laryngeal inflammation. Establishing whether and how the laryngeal mucosa may be involved in the modulation of wider mucosal responses may provide novel routes to the treatment of inflammatory diseases of the respiratory and alimentary tracts such as asthma and inflammatory bowel disease.

Vocal fatigue and its relation to vocal hyperfunction †

This article reviews current literature on vocal fatigue and considers its potential relationship to vocal hyperfunction. Vocal fatigue is defined by its symptoms. Specifically, the voice user perceives an increase in phonatory effort over time that may be accompanied by decreased phonatory function. Vocal fatigue can present as a pure condition, such that no specific aetiology is apparent, or as a component of other voice disorders. The underlying bases of vocal fatigue appear to include the neurophysiological and biomechanical effects of extended periods of phonation. It can also be a function of strategies used to adapt to extended periods of phonation, such as the use of excessive muscular tension and suboptimal vocal fold posturing. Studies that have attempted to identify observable responses that are reliably associated with vocal fatigue have met with limited success, but recent advances in research methodology are promising. This review addresses current approaches to the study of vocal fatigue, especially regarding subject selection, design variables, and measurement variables. Future studies should address the relationship between vocal fatigue and other voice disorders, differences in individual responses to vocal-loading tasks, and differential evaluation and management of the neuromuscular, biomechanical, and central processes involved in vocal fatigue.

Fine needle aspiration: a novel application in laryngology

Fine needle aspiration (FNA) has had an early start in medicine and has been heavily used in the United States since the 1980s. It is regarded as a highly effective means to sample mass lesions, serving as the first diagnostic procedure in many instances. FNA is safe, less invasive than biopsy, and reduces the risk of scar formation. Its main limitations can be overcome through effective training and practiced technique. In laryngology, the development of new and diversified therapeutic and diagnostic strategies depends on the development of equally appropriate diagnostic tools. FNA has the potential to be a relatively easy procedure that can be performed under local anesthesia, increasing the otolaryngologist's armamentarium. Combining the FNA procedure with technology now available, secondary to advances in genomic science, rather than cytology and H&E stains, provides the means of obtaining clinically useful information about benign and malignant disease for clinicians and researchers. This paper provides a review of the traditional FNA procedure. It offers an introduction to the future applicability of FNA to office-based laryngology. Lastly, this paper familiarizes the reader with the genomic principles being used for this procedure.