Faculty Bibliography

Decellularized extracellular matrix (ECM) scaffolds derived from tissues and organs are complex biomaterials used in clinical and research applications. A number of decellularization protocols have been described for ECM biomaterials derivation, each adapted to a particular tissue and use, restricting comparisons among materials. One of the major sources of variability in ECM products comes from the tissue source and animal age. Although this variability could be minimized using established tissue sources, other sources arise from the decellularization process itself. Overall, current protocols require manual work and are poorly standardized with regard to the choice of reagents, the order by which they are added, and exposure times. The combination of these factors adds variability affecting the uniformity of the final product between batches. Furthermore, each protocol needs to be optimized for each tissue and tissue source making tissue-to-tissue comparisons difficult. Automation and standardization of ECM scaffold development constitute a significant improvement to current biomanufacturing techniques but remains poorly explored. This study aimed to develop a biofabrication method for fast and automated derivation of raw material for ECM hydrogel production while preserving ECM composition and controlling lot-to-lot variability. The main result was a closed semibatch bioreactor system with automated dosing of decellularization reagents capable of deriving ECM material from pretreated soft tissues. The ECM was further processed into hydrogels to demonstrate gelation and cytocompatibility. This work presents a versatile, scalable, and automated platform for the rapid production of ECM scaffolds.

The vocal fold lamina propria (VFLP), one of the outermost layers of the vocal fold (VF), is composed of tissue-specific extracellular matrix (ECM) proteins and is highly susceptible to injury. Various biomaterials have been clinically tested to treat voice disorders (e.g., hydrogels, fat, and hyaluronic acid), but satisfactory recovery of the VF functionality remains elusive. Fibrosis or scar formation in the VF is a major challenge, and the development and refinement of novel therapeutics that promote the healing and normal function of the VF are needed. Injectable hydrogels derived from native tissues have been previously reported with major advantages over synthetic hydrogels, including constructive tissue remodeling and reduced scar tissue formation. This study aims to characterize the composition of a decellularized porcine VFLP-ECM scaffold and the cytocompatibility and potential antifibrotic properties of a hydrogel derived from VFLP-ECM. In addition, we isolated potential matrix-bound vesicles (MBVs) and macromolecules from the VFLP-ECM that also downregulated smooth muscle actin ACTA2 under transforming growth factor-beta 1 (TGF-β1) stimulation. The results provide evidence of the unique protein composition of the VFLP-ECM and the potential link between the components of the VFLP-ECM and the inhibition of TGF-β1 signaling observed in vitro when transformed into injectable forms.

OBJECTIVES/OBJECTIVE:Development of novel vocal fold (VF) therapeutics is limited by a lack of standardized, meaningful outcomes. We hypothesize that automated microindentation-based VF biomechanical property mapping matched to histology permits quantitative assessment. STUDY DESIGN/METHODS:Ex vivo. METHODS:Twelve anesthetized New Zealand white rabbits underwent endoscopic right VF injury. Larynges were harvested/bisected day 7, 30, or 60 (n = 4/group), with four uninjured controls. Biomechanical measurements (normal force, structural stiffness, and displacement at 1.96 mN) were calculated using automated microindentation mapping (0.3 mm depth, 1.2 mm/s, 2 mm spherical indenter) with a grid overlay (>50 locations weighted toward VF edge, separated into 14 zones). Specimens were marked/fixed/sectioned, and slides matched to measurement points. RESULTS:In the injury zone, normal force/structural stiffness (mean, standard deviation [SD]/mean, SD) increased from uninjured (2.2 mN, 0.64/7.4 mN/mm, 2.14) and day 7 (2.7 mN, 0.75/9.0 mN/mm, 2.49) to day 30 (4.3 mN, 2.11/14.2 mN/mm, 7.05) and decreased at 60 days (2.7 mN, 0.77/9.1 mN/mm, 2.58). VF displacement decreased from control (0.28 mm, 0.05) and day 7 (0.26 mm, 0.05) to day 30 (0.20 mm, 0.05), increasing at day 60 (0.25 mm, 0.06). A one-way ANOVA was significant; Tukey's post hoc test confirmed day-30 samples differed from other groups (P < 0.05), consistent across adjacent zones. Zones far from injury remained similar across groups (P = 0.143 to 0.551). These measurements matched qualitative histologic variations. CONCLUSION/CONCLUSIONS:Quantifiable VF biomechanical properties can be linked to histology. This technological approach is the first to simultaneously correlate functional biomechanics with histology and is ideal for future preclinical studies. LEVEL OF EVIDENCE/METHODS:NA Laryngoscope, 2019.

Objective/UNASSIGNED:were assayed to optimize siRNA-mediated alteration of gene expression. Methods/UNASSIGNED:-siRNA complex. Results/UNASSIGNED:-complexed Smad3 siRNA at 1 day postinjection. Qualitative suppression of Smad3 expression persisted to 3 days following injury, but did not achieve statistical significance. Conclusions/UNASSIGNED:yielded effective, yet temporally limited knockdown of Smad3 in vivo. Peptoids may provide a versatile platform for the discovery of siRNA delivery vehicles optimized for clinical application. Level of Evidence/UNASSIGNED:NA.

Recurrent Respiratory Papillomatosis (RRP) is a rare disease of the aerodigestive tract caused by the Human Papilloma Virus (HPV) that manifests as profoundly altered phonatory and upper respiratory anatomy. Current therapies are primarily symptomatic; enhanced insight regarding disease-specific biology of RRP is critical to improved therapeutics for this challenging population. Multiplex PCR was performed on oral rinses collected from twenty-three patients with adult-onset RRP every three months for one year. Twenty-two (95.6%) subjects had an initial HPV positive oral rinse. Of those subjects, 77.2% had an additional positive oral rinse over 12 months. A subset of rinses were then compared to tissue samples in the same patient employing HPViewer to determine HPV subtype concordance. Multiple HPV copies (60-787 per human cell) were detected in RRP tissue in each patient, but a single dominant HPV was found in individual samples. These data confirm persistent oral HPV infection in the majority of patients with RRP. In addition, three novel HPV6 isolates were found and identical HPV strains, at very low levels, were identified in oral rinses in two patients suggesting potential HPV subtype concordance. Finally, somatic heteroplasmic mtDNA mutations were observed in RRP tissue with 1.8 mutations per sample and two nonsynonymous variants. These data provide foundational insight into both the underlying pathophysiology of RRP, but also potential targets for intervention in this challenging patient cohort.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:To describe recurrence patterns in patients with recurrent respiratory papillomatosis (RRP) following surgical intervention. STUDY DESIGN/METHODS:Single-center, retrospective, longitudinal case series. METHODS:Initial and follow-up laryngoscopic examinations of seven previously untreated adult-onset RRP patients were reviewed. Patients were followed longitudinally for periods ranging from 3 months to 7 years. Lesion locations were recorded using a twenty-one region laryngeal schematic, and maps were generated to illustrate the distribution of disease before and after cold-knife or potassium-titanyl-phosphate laser intervention. Univariate and multivariate analyses were employed to examine variables affecting recurrence patterns. RESULTS:Across all patients, a statistically significant correlation between initial distribution and primary recurrence was observed. Seventy-five percent of new lesions were adjacent to regions with preexisting disease; 83% of new glottic lesions were adjacent to preexisting glottic lesions, and 66% of supraglottic lesions were adjacent to preexisting supraglottic regions. No statistically significant differences in recurrence rate were observed across sites. CONCLUSIONS:In previously untreated patients with adult-onset recurrent respiratory papillomatosis, lesions tended to recur either in the same regions or regions adjacent to those affected at the time of initial surgery. LEVEL OF EVIDENCE/METHODS:4 Laryngoscope, 2019.

OBJECTIVE:Given that financial considerations play an increasingly prominent role in clinical decision-making, we sought (1) to determine the cost-effectiveness of in-office biopsy for the patient, the provider, and the health-care system, and (2) to determine the diagnostic accuracy of in-office biopsy. STUDY DESIGN/METHODS:Retrospective, financial analyses were performed. METHODS:Patients who underwent in-office (Current Procedural Terminology Code 31576) or operative biopsy (CPT Code 31535) for laryngopharyngeal lesions were included. Two financial analyses were performed: (1) the average cost of operating room (OR) versus in-office biopsy was calculated, and (2) a break-even analysis was calculated to determine the cost-effectiveness of in-office biopsy for the provider. In addition, the diagnostic accuracy of in-office biopsies and need for additional biopsies or procedures was recorded. RESULTS:Of the 48 patients included in the current study, 28 underwent in-office biopsy. A pathologic sample was obtained in 26 of 28 (92.9%) biopsies performed in the office. Of these patients, 16 avoided subsequent OR procedures. The average per patient cost was $7000 and $11,000 for in-office and OR biopsy, respectively. Break-even analysis demonstrated that the provider could achieve a profit 2 years after purchase of the necessary equipment. CONCLUSION/CONCLUSIONS:In-office laryngopharyngeal biopsies are accurate and, overall, more cost-effective than OR biopsies. Purchase of the channeled, distal chip laryngoscope and biopsy forceps to perform in-office biopsies can be profitable for a provider with a videolaryngoscopy tower. In-office biopsy should be considered the initial diagnostic tool for suspected laryngopharyngeal malignancies noted on videolaryngoscopy.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Direct glucocorticoid (GC) injection for vocal fold (VF) scarring has evolved as a therapeutic strategy, but the mechanisms underlying the antifibrotic effects remain unclear. GCs act via the glucocorticoid receptor (GR), which is phosphorylated at multiple serine residues in a hormone-dependent manner to affect bioactivity. We hypothesize that GCs regulate SMAD signaling via GR phosphorylation in vocal fold fibroblasts (VFFs). STUDY DESIGN/METHODS:In vitro. METHODS:phosphorylation was examined via sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunocytochemistry. Quantitative polymerase chain reaction was employed to determine GR-mediated effects of DM on genes related to fibrosis. RESULTS:phosphorylation increased. RU486 limited the effects of DM. SMAD3 and SMAD7 mRNA expression significantly decreased 4 hours after DM administration (P < 0.05); this response was negated by RU486. COL1A1 remained unchanged, and ACTA2 significantly increased following 24 hours of DM treatment (P < 0.05). CONCLUSION/CONCLUSIONS:DM regulated TGF-β1 signaling via altered SMAD3 and SMAD7 expression. This response was associated with altered GR phosphorylation. These findings provide insight into the mechanisms of steroidal effects on vocal fold repair; ultimately, we seek to enhance therapeutic strategies for these challenging patients. LEVEL OF EVIDENCE/METHODS:NA. Laryngoscope, 2018.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Various animal models have been employed to investigate vocal fold (VF) and phonatory function. However, biomechanical testing techniques to characterize vocal fold structural properties vary and have not compared critical properties across species. We adapted a nondestructive, automated indentation mapping technique to simultaneously quantify VF structural properties (VF cover layer and intact VF) in commonly used species based on the hypothesis that VF biomechanical properties are largely preserved across species. STUDY DESIGN/METHODS:Ex vivo animal model. METHODS:Canine, leporine, and swine larynges (n = 4 each) were sagittally bisected, measured, and subjected to normal indentation mapping (indentation at 0.3 mm; 1.2 mm/s) with a 2-mm spherical indenter to quantify normal force along the VF cover layer, structural stiffness, and displacement at 0.8 mN; two-dimensional maps of the free VF edge through the conus elasticus were created for these characterizations. RESULTS:Structural stiffness was 7.79 gf/mm (0.15-74.55) for leporine, 2.48 gf/mm (0.20-41.75) for canine, and 1.45 gf (0.56-4.56) for swine. For each species, the lowest values were along the free VF edge (mean ± standard deviation; leporine: 0.40 ± 0.21 gf/mm, canine: 1.14 ± 0.49 gf/mm, swine: 0.89 ± 0.28 gf/mm). Similar results were obtained for the cover layer normal force at 0.3 mm. On the free VF edge, mean (standard deviation) displacement at 0.08 gf was 0.14 mm (0.05) in leporine, 0.11 mm (0.03) in canine, and 0.10 mm (0.02) in swine. CONCLUSIONS:Automated indentation mapping yielded reproducible biomechanical property measurement of the VF cover and intact VF. Divergent VF structural properties across canine, swine, and leporine species were observed. LEVEL OF EVIDENCE/METHODS:NA. Laryngoscope, 2018.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Our laboratory recently described NR4A1 as an endogenous inhibitor of TGF-β-induced vocal fold (VF) fibrosis. Our prior report described the temporal expression of NR4A1 during VF healing in vivo and the effects of NR4A1 knockdown on fibroplastic cell activities in vitro. Based on these findings, we hypothesized that cytosporone-B (Csn-B), an NR4A1 agonist, may hold significant therapeutic potential. STUDY DESIGN/METHODS:In vitro. METHODS:Human VF fibroblasts were exposed to TGF-β1+/-Csn-B. Expression of genes related to fibrosis were quantified. In addition, contraction was assayed as a surrogate for the fibrotic phenotype in our cell line. RESULTS:TGF-B1 stimulated COL1A1 and ACTA2, as expected. Csn-B significantly downregulated TGF-β1-mediated upregulation of these genes (P = .009, P = .03, respectively). Csn-B had no effect on genes related to TGF-β/Smad signaling. Csn-B also decreased the TGF-β1-mediated contractile phenotype in our cells (P = .004). CONCLUSIONS:NR4A1 is an endogenous inhibitor of fibrosis in the vocal folds and Csn-B, as an NR4A1 agonist, may evolve as an ideal, therapeutic candidate for this challenging condition. LEVEL OF EVIDENCE/METHODS:NA Laryngoscope, 2018.