Murine Model of Airway Fibrosis has Anatomic, Physiologic, and Molecular Congruency to Human iSGS

OBJECTIVE

To narrow knowledge gaps in the pathophysiology of idiopathic subglottic stenosis (iSGS) through comparison of a murine subglottic stenosis model with iSGS.

STUDY DESIGN

In vivo animal study.

SETTING

Academic institution.

METHODS

Murine samples/measurements were obtained from mice that underwent chemomechanical injury with a wire brush and bleomycin. Human samples/measurements were obtained from iSGS patients. Anatomic, physiologic, and epithelial molecular data were collected using histology, human peak expiratory flow (PEF) and murine airway conductance, gene expression analysis with quantitative polymerase chain reaction, and protein analysis with quantitative immunohistochemistry.

RESULTS

Anatomic patterns of scars at the subglottis and proximal trachea seen in the murine model are similar to iSGS patients. Subglottic stenosis (SGS) mice had a decrease (P = .0194) in airway conductance compared to healthy controls, similar to a decrease (P = .0001) in predilation PEF versus postdilation in iSGS patients. There was decreased epithelial gene expression of E-cadherin (ECAD) (P < 0.01), occludin (OCLN) (P < .01), and cytokeratin-5 (CK5) (P < .05) and protein expression of ECAD (H/M: P < .001), OCLN (H: P < 0.05, M: P < .001), and CK5 (H: P < .001, M: P < .01) in murine SGS and iSGS versus controls.

CONCLUSION

The murine SGS model shows anatomic, physiologic, and molecular congruency with human iSGS, making it a reasonable model to investigate iSGS. The molecular similarities in epithelial barrier dysfunction suggest it may best be suited to explore epithelial mechanisms of iSGS and therapies directed at epithelial reconstitution. This model provides a foundation to collect data that will improve understanding of iSGS, and, ultimately, translate into more accurate animal models for future use.

Characterizing the Macrophage Population in Patients With Idiopathic Subglottic Stenosis

OBJECTIVES

Idiopathic subglottic stenosis (iSGS) is characterized by progressive fibrosis and subglottic luminal narrowing. Currently, immune characterization has focused on T-cells; however, macrophages remain largely unexplored. The goals of this study are to characterize the transcriptome of iSGS macrophages and the fibrogenic nature of identifed biomarkers.

STUDY DESIGN

Bioinformatics and in vitro.

METHODS

Human tracheal biopsies from iSGS scar (n = 4), and matched non-scar (n = 4) regions were analyzed using single-cell RNA-seq (scRNA-seq). Immunofluorescence (IF) was performed on rapidly processed autopsies (RPA) and iSGS tracheal resections (n = 4) to co-localize S100A8/9 and CD11b. Collagen gene/protein expression was assessed in iSGS fibroblasts (n = 4) treated with protein S100A8/9 (1000 ng/ml). Macrophages were subclustered to identify distinct subpopulations.

RESULTS

scRNA-seq analysis revealed S100A8/S100A9 (fold change (FC) = 4.1/1.88, p < 0.001) as top differentially expressed genes in iSGS macrophages. IF exhibited increased CD11b+/S100A8/9+ cells in tracheal samples of iSGS versus RPA (26.75% ± 7.08 vs. 0.594% ± 0.974, n = 4, p = 0.029). iSGS fibroblasts treated with S100A8/9 demonstrated increased gene expression of COL1A1 (FC = 2.30 ± 0.45, p = 0.03, n = 4) and COL3A1 (FC = 2.44 ± 0.40, p = 0.03, n = 4). COL1A1 protein assays revealed an increase in the experimental group, albeit not significant, (p = 0.12, n = 4). Finally, macrophage sub clustering revealed one subpopulation as a predominant source of S100A8/S100A9 expression (FC = 7.94/5.47, p < 0.001).

CONCLUSIONS

S100A8/9 is a key biomarker in iSGS macrophages. Although S100A8/9 demonstrates profibrotic nature in vitro, the role of S100A8/9+ macrophages in vivo warrants further investigation.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:2308-2316, 2023.

Idiopathic subglottic stenosis arises at the epithelial interface of host and pathogen

Background

Idiopathic subglottic stenosis (iSGS) is a rare fibrotic disease of the proximal airway affecting adult Caucasian women nearly exclusively. Life-threatening ventilatory obstruction occurs secondary to pernicious subglottic mucosal scar. Disease rarity and wide geographic patient distribution has previously limited substantive mechanistic investigation into iSGS pathogenesis.

Result

By harnessing pathogenic mucosa from an international iSGS patient cohort and single-cell RNA sequencing, we unbiasedly characterize the cell subsets in the proximal airway scar and detail their molecular phenotypes. Results show that the airway epithelium in iSGS patients is depleted of basal progenitor cells, and the residual epithelial cells acquire a mesenchymal phenotype. Observed displacement of bacteria beneath the lamina propria provides functional support for the molecular evidence of epithelial dysfunction. Matched tissue microbiomes support displacement of the native microbiome into the lamina propria of iSGS patients rather than disrupted bacterial community structure. However, animal models confirm that bacteria are necessary for pathologic proximal airway fibrosis and suggest an equally essential role for host adaptive immunity. Human samples from iSGS airway scar demonstrate adaptive immune activation in response to the proximal airway microbiome of both matched iSGS patients and healthy controls. Clinical outcome data from iSGS patients suggests surgical extirpation of airway scar and reconstitution with unaffected tracheal mucosa halts the progressive fibrosis.

Conclusion

Our data support an iSGS disease model where epithelial alterations facilitate microbiome displacement, dysregulated immune activation, and localized fibrosis. These results refine our understanding of iSGS and implicate shared pathogenic mechanisms with distal airway fibrotic diseases.

A survey of patients with laryngotracheal stenosis on future clinical trial design

BACKGROUND/AIMS

Laryngotracheal stenosis is a rare but devastating proximal airway fibrosis that restricts a patient's ability to breathe. Treatment is primarily surgical and to date, there has never been a multi-institutional, randomized, prospective, and interventional clinical trial for a medical therapy to treat laryngotracheal stenosis. Therefore, we aimed to obtain patient feedback to guide successful trial design, recruitment, retention, and for identifying potential barriers to study participation.

METHODS

Over 1000 members of an international laryngotracheal stenosis online support community (the Living with Idiopathic Subglottic Stenosis Facebook group) were sent two questionnaires for a proposed interventional double-blinded, randomized, placebo-controlled clinical trial.

RESULTS

A total of 317 and 558 participants responded to the first and second surveys, respectively. The majority of participants (77%) were willing to consider enrollment, regardless of having a 50% chance of receiving placebo versus treatment (78%). The majority (84%) of participants were willing to travel 200 miles to participate for up to six in-person visits over 50 days. Specific side effects, including anemia/thrombocytopenia (72%) or risk of infection (69.3%) had the greatest impact on clinical trial participation with other side effects (peripheral edema (53%), oral ulcers (51%), and gastrointestinal side effects (41%)) having less impact.

CONCLUSION

Patients with laryngotracheal stenosis possess nuanced insight into their disease and treatment options. As a group, they are extremely motivated for better therapies. Future laryngotracheal stenosis clinical trials should focus on providing excellent side effect -related education and utilizing feedback from online advocacy groups to optimize recruitment and retention.

Endoscopic Resection and Mucosal Reconstitution With Epidermal Grafting: A Pilot Study in Idiopathic Subglottic Stenosis

OBJECTIVE

To describe technical aspects and surgical outcomes of endoscopic resection and mucosal reconstitution with epidermal grafting (ie, the Maddern procedure) in the treatment of idiopathic subglottic stenosis.

STUDY DESIGN

Medical record abstraction.

SETTING

Johns Hopkins Hospital.

METHODS

Retrospective series of 9 adults with idiopathic subglottic stenosis who underwent the Maddern procedure by a single surgeon over a 5-year period. Prespecified outcomes included (1) perioperative outcomes (Clavien-Dindo grade 4/5 complications, need for staged tracheostomy, hospital length of stay), (2) postoperative outcomes (peak expiratory flow rate [PEFR], need for subsequent airway surgery, tracheostomy at follow-up), and (3) patient-reported quality-of-life outcomes (Clinical COPD Questionnaire, Voice Handicap Index-10, Eating Assessment Tool-10, and 12-Item Short Form Version 2). Wilcoxon matched-pairs signed rank test and Kaplan-Meier analysis were performed.

RESULTS

There were no Clavien-Dindo grade 4/5 complications; 2 patients required unplanned staged tracheostomy; and the median length of stay was 3 days. Following endoscopic resection and stent removal, a median of 2 laser resurfacing procedures were required. Two patients developed recurrent stenosis requiring cricotracheal resection (CTR). There were significant improvements in PEFR, Clinical COPD Questionnaire, and Voice Handicap Index-10, without significant difference in Eating Assessment Tool-10. The 12-Item Short Form Version 2 approximated the population norm. Kaplan-Meier analysis demonstrated significant improvement in time to surgery after the final laser resurfacing.

CONCLUSION

The Maddern procedure has a low complication rate and offers durable physiologic improvement in PEFR, limiting need for additional procedures. Risks included need for CTR salvage, temporary tracheostomy, phlegm accumulation, and laryngospasm. It is a surgical option for patients with short dilation intervals who prefer to avoid the risks of CTR.

Quantitative Assessment of the Immune Microenvironment in Patients With Iatrogenic Laryngotracheal Stenosis

OBJECTIVE

Iatrogenic laryngotracheal stenosis (iLTS) is characterized by fibroinflammatory narrowing of the upper airway and is most commonly caused by intubation injury. Evidence suggests a key role for CD4 T cells in its pathogenesis. The objective of this study is to validate emerging multiplex immunofluorescence (mIF) technology for use in the larynx and trachea while quantitatively characterizing the immune cell infiltrate in iLTS. In addition to analyzing previously unstudied immune cell subsets, this study aims to validate previously observed elevations in the immune checkpoint PD-1 and its ligand PD-L1 while exploring their spatial and cellular distributions in the iLTS microenvironment.

STUDY DESIGN

Controlled ex vivo cohort study.

SETTING

Tertiary care center.

METHODS

mIF staining was performed with formalin-fixed, paraffin-embedded slides from 10 patients with iLTS who underwent cricotracheal resection and 10 control specimens derived from rapid autopsy for CD4, CD8, CD20, FoxP3, PD-1, PD-L1, and cytokeratin.

RESULTS

There was greater infiltration of CD4+ T cells, CD8+ T cells, CD20+ B cells, FoxP3+CD4+ Tregs, and FoxP3+CD8+ early effector T cells in the submucosa of iLTS specimens as compared with controls (P < .05 for all). PD-1 was primarily expressed on T cells and PD-L1 predominantly on CD4+ cells and "other" cells.

CONCLUSION

This study leverages the power of mIF to quantify the iLTS immune infiltrate in greater detail. It confirms the highly inflammatory nature of iLTS, with CD4+ cells dominating the immune cell infiltrate; it further characterizes the cellular and spatial distribution of PD-1 and PD-L1; and it identifies novel immunologic targets in iLTS.

Factors Affecting Dilation Interval in Patients With Granulomatosis With Polyangiitis-Associated Subglottic and Glottic Stenosis

OBJECTIVE

Subglottic stenosis (SGS) is a known complication of granulomatosis with polyangiitis (GPA). We investigated the impact of medical and surgical interventions on the surgical dilation interval and characterized patients with glottic involvement.

STUDY DESIGN

A retrospective chart review of patients with GPA-associated SGS was performed from 2010 to 2019.

SETTING

Tertiary academic medical center.

METHODS

The impact of medical and surgical interventions on dilation interval was assessed. The prevalence of glottic involvement was assessed, and clinical characteristics and outcomes were compared with patients without glottic involvement.

RESULTS

A total of 39 patients with GPA-associated SGS were analyzed. Dilation intervals in patients receiving leflunomide (n = 4; median, 484 days; 95% CI, 405-1099) were greater than in those not receiving leflunomide (median, 155 days; 95% CI, 48-305; P = .033). The surgical technique used did not affect dilation interval. Patients with glottic involvement (n = 13) had a greater incidence of dysphonia (13/13 vs 15/26 [58%], P = .007) and a shorter dilation interval with involvement (median, 91 days; interquartile range, 70-277) versus without involvement (median, 377 days; interquartile range, 175-1148; hazard ratio, 3.38; 95% CI, 2.26-5.05; P < .001). Of 13 patients, 8 (62%) did not have glottic involvement on first presentation.

CONCLUSION

Although GPA is classically thought to affect the subglottis, it also involves the glottis in a subset of patients. These patients have greater complaints of dysphonia and require more frequent surgery. Systemic therapy may increase dilation intervals. In this preliminary study, patients taking leflunomide demonstrated an improvement, highlighting the need for further study of immunosuppression regimens in the treatment of GPA-associated SGS.

M2 Macrophages Promote Collagen Expression and Synthesis in Laryngotracheal Stenosis Fibroblasts

OBJECTIVE

Macrophages exhibit distinct phenotypes and are dysregulated in a model of iatrogenic laryngotracheal stenosis (iLTS). Increased populations of alternatively activated or M2 macrophages have been demonstrated. However, the role of these macrophages is unknown. The aims of this study are: 1) define the macrophage population in iLTS in the context of classically activated or M1 and M2 macrophage phenotypes, and 2) characterize the effect of monocyte-derived M1 and M2 macrophages on normal airway and LTS-derived fibroblasts (FBs) in vitro.

STUDY DESIGN

Comparative analysis; in vitro controlled study.

METHODS

Immunohistochemical analysis of human iLTS and control specimens was performed to define the macrophage population. In vitro, M1, and M2 macrophages were polarized using M-CSF + Interferon-gamma and lipopolysaccharide or Interleukin-4, respectively. FBs isolated from laryngotracheal scar (LTS-FBs) and normal tracheal airway (NA-FBs) in eight patients with iLTS were cocultured with polarized macrophages. Fibrosis gene expression, soluble collagen production, and proliferation were assessed.

RESULTS

Immunohistochemical analysis revealed increased CD11b + cells (macrophage marker) in laryngotracheal scar specimens (18.3% vs. 8.5%, P = .03) and predominant CD206 (M2) costaining versus CD86 (M1) (51.5% vs. 9.8%, n = 10, P = .001). In vitro, NA-FBs cultured with M2 macrophages demonstrated a 2.41-fold increase in collagen-1 expression (P = .05, n = 8) and an increase in soluble collagen (9.98 vs. 8.875, mean difference: 1.11 95%, confidence interval 0.024-2.192, n = 8, P = .015).

CONCLUSION

Increased populations of CD11b cells are present in iLTS specimens and are predominantly CD206+, indicating an M2 phenotype. In vitro, M2 macrophages promoted collagen expression in airway FBs. Targeting macrophages may represent a therapeutic strategy for attenuating fibrosis in iLTS.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:E346-E353, 2021.

Design of a Biocompatible Drug-Eluting Tracheal Stent in Mice with Laryngotracheal Stenosis

Laryngotracheal stenosis (LTS) is a pathologic narrowing of the subglottis and trachea leading to extrathoracic obstruction and significant shortness of breath. LTS results from mucosal injury from a foreign body in the trachea, leading to tissue damage and a local inflammatory response that goes awry, leading to the deposition of pathologic scar tissue. Treatment for LTS is surgical due to the lack of effective medical therapies. The purpose of this method is to construct a biocompatible stent that can be miniaturized to place into mice with LTS. We demonstrated that a PLLA-PCL (70% poly-L-lactide and 30% polycaprolactone) construct had optimal biomechanical strength, was biocompatible, practicable for an in vivo placement stent, and capable of eluting drug. This method provides a drug delivery system for testing various immunomodulatory agents to locally inhibit inflammation and reduce airway fibrosis. Manufacturing the stents takes 28-30 h and can be reproduced easily, allowing for experiments with large cohorts. Here we incorporated the drug rapamycin within the stent to test its effectiveness in reducing fibrosis and collagen deposition. Results revealed that PLLA-PCL tents showed reliable rapamycin release, were mechanically stable in physiological conditions, and were biocompatible, inducing little inflammatory response in the trachea. Further, the rapamycin-eluting PLLA-PCL stents reduced scar formation in the trachea in vivo.

Engineering an immunomodulatory drug-eluting stent to treat laryngotracheal stenosis

OBJECTIVE

Develop a drug-eluting stent construct with a reliable drug-release profile and adequate mechanically stability for a trial in a small animal model of laryngotracheal stenosis (LTS), a debilitating pathologic narrowing of the airway leading to significant shortness of breath.

METHODS

Biodegradable, biocompatible stents containing 1.0% rapamycin made of PLLA-PCL (70% Poly-l-Lactide and 30% Polycaprolactone blend) and 50 : 50 PDLGA (Poly(dl-lactide-co-glycolide)) were compared. Mechanical strength testing and drug elution rates using high performance liquid chromatography analysis (HPLC) was assessed. Next, efficacy of stent elution on LTS derived scar fibroblasts. Finally, stents were placed in situ in an LTS mouse model.

RESULTS

The PLLA-PCL stent construct exhibited greater mechanical strength compared to the PDLGA stent over a 4-week period (Young's Modulus (PLLA-PCL) = 13.82; Young's Modulus (PDLGA) = 4.015). Moreover, the PLLA-PCL stent showed a reliable rapamycin release profile for 6 weeks (30% elution for PLLA-PCL stents compared to <1% elution for PDLGA). Collagen 1 (p < 0.05) and fibroblast cell proliferation were decreased in vitro when treated with the rapamycin stent. In vivo, the rapamycin stent reduced lamina propria thickness (p < 0.05) and collagen 1(p < 0.05), collagen 3, TGF-B (p < 0.05) and a-SMA (p < 0.05).

CONCLUSIONS

The PLLA-PCL construct demonstrated superior mechanical strength and greater drug elution compared to PDLGA stents. We demonstrated the feasibility of testing this drug-eluting stent in vivo, showing that the rapamycin-eluting stent treats fibrosis. To our knowledge this is the first study to deploy a drug-eluting stent to treat tracheal pathology in an animal model. Optimization of a rapamycin-eluting PLLA-PCL stent for translational investigation will lead to improved treatment strategies of LTS.

Laryngotracheal Microbiota in Adult Laryngotracheal Stenosis

Laryngotracheal stenosis is an obstructive respiratory disease that leads to voicing difficulties and dyspnea with potential life-threatening consequences. The majority of incidences are due to iatrogenic etiology from endotracheal tube intubation; however, airway scarring also has idiopathic causes. While recent evidence suggests a microbial contribution to mucosal inflammation, the microbiota associated with different types of stenosis has not been characterized. High-throughput sequencing of the V4 region of the16S rRNA gene was performed to characterize the microbial communities of 61 swab samples from 17 iatrogenic and 10 adult idiopathic stenosis patients. Nonscar swabs from stenosis patients were internal controls, and eight swabs from four patients without stenosis represented external controls. Significant differences in diversity were observed between scar and nonscar samples and among sample sites, with decreased diversity detected in scar samples and the glottis region. Permutational analysis of variance (PERMANOVA) results revealed significant differences in community composition for scar versus nonscar samples, etiology type, sample site, groups (iatrogenic, idiopathic, and internal and external controls), and individual patients. Pairwise Spearman's correlation revealed a strong inverse correlation between Prevotella and Streptococcus among all samples. Finally, bacteria in the family Moraxellaceae were found to be distinctly associated with idiopathic stenosis samples in comparison with external controls. Our findings suggest that specific microbiota and community shifts are present with laryngotracheal stenosis in adults, with members of the family Moraxellaceae, including the known pathogens Moraxella and Acinetobacter, identified in idiopathic scar. Further work is warranted to elucidate the contributing role of bacteria on the pathogenesis of laryngotracheal stenosis.IMPORTANCE The laryngotracheal region resides at the intersection between the heavily studied nasal cavity and lungs; however, examination of the microbiome in chronic inflammatory conditions of the subglottis and trachea remains scarce. To date, studies have focused on the microbiota of the vocal folds, or the glottis, for laryngeal carcinoma, as well as healthy larynges, benign vocal fold lesions, and larynges exposed to smoking and refluxate. In this study, we seek to examine the structure and composition of the microbial community in adult laryngotracheal stenosis of various etiologies. Due to the heterogeneity among the underlying pathogenesis mechanisms and clinical outcomes seen in laryngotracheal stenosis disease, we hypothesized that different microbial profiles will be detected among various stenosis etiology types. Understanding differences in the microbiota for subglottic stenosis subtypes may shed light upon etiology-specific biomarker identification and offer novel insights into management approaches for this debilitating disease.

Health Care Costs and Cost-effectiveness in Laryngotracheal Stenosis

OBJECTIVE

Laryngotracheal stenosis (LTS) is resource-intensive disease. The cost-effectiveness of LTS treatments has not been adequately explored. We aimed to conduct a cost-effectiveness analysis comparing open reconstruction (cricotracheal/tracheal resection [CTR/TR]) with endoscopic dilation in the treatment of LTS.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary referral center (2013-2017).

SUBJECTS AND METHODS

Thirty-four LTS patients were recruited. Annual costs were derived from the Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University. Cost-effectiveness analysis compared CTR/TR versus endoscopic dilation at a willingness-to-pay threshold of $50,000 per quality-adjusted life year (QALY) over 5- and 10-year time horizons. The incremental cost-effectiveness ratio (ICER) was calculated with deterministic analysis and tested for sensitivity with univariate and probabilistic sensitivity analysis.

RESULTS

Mean LTS costs were $4080.09 (SE, $569.29) annually for related health care visits. The major risk factor for increased cost was etiology of stenosis. As compared with idiopathic patients, patients with intubation-related stenosis had significantly higher annual costs ($5286.56 vs $2873.62, P = .03). The cost of CTR/TR was $8583.91 (SE, $2263.22). Over a 5-year time horizon, CTR/TR gained $896 per QALY over serial dilations and was cost-effective. Over a 10-year time horizon, CTR/TR dominated dilations with a lower cost and higher QALY.

CONCLUSION

The cost of treatment for LTS is significant. Patients with intubation-related stenosis have significantly higher annual costs than do idiopathic patients. CTR/TR contributes significantly to cost in LTS but is cost-effective versus endoscopic dilations for appropriately selected patients over a 5- and 10-year horizon.

T-Helper 2 Lymphocyte Immunophenotype Is Associated With Iatrogenic Laryngotracheal Stenosis

OBJECTIVE/HYPOTHESIS

This prospective controlled human and murine study assessed the presence of inflammatory cells and cytokines to test the hypothesis that immune cells are associated with fibroproliferation in iatrogenic laryngotracheal stenosis (iLTS).

METHODS

Inflammation was assessed by histology and immunofluorescence (IF), quantitative real-time polymerase chain reaction (qRT-PCR), and flow cytometry of cricotracheal resections of iLTS patients compared to normal controls. An iLTS murine model assessed the temporal relationship between inflammation and fibrosis.

RESULTS

iLTS specimens showed increased inflammation versus normal controls (159/high power field [hpf] vs. 119/hpf, P = 0.038), and increased CD3 + T-cells, CD4 + cells, and CD3+/CD4 + T-helper (T_H ) cells (all P < 0.05). The inflammatory infiltrate was located immediately adjacent to the epithelial surface in the superficial aspect of the thickened lamina propria. Human flow cytometry and qRT-PCR showed a significant increase in interleukin (IL)-4 gene expression, indicating a T_H 2 phenotype. Murine IF revealed a dense CD4 + T-cell inflammatory infiltrate on day 4 to 7 postinjury, which preceded the development of fibrosis. Murine flow cytometry and qRT-PCR studies mirrored the human ones, with increased T-helper cells and IL-4 in iLTS versus normal controls.

CONCLUSION

CD3/CD4 + T-helper lymphocytes and the proinflammatory cytokine IL-4 are associated with iLTS. The association of a T_H 2 immunophenotype with iLTS is consistent with findings in other fibroinflammatory disorders. The murine results reveal that the inflammatory infiltrate precedes the development of fibrosis. However, human iLTS specimens with well-developed fibrosis also contain a marked chronic inflammatory infiltrate, suggesting that the continued release of IL-4 by T-helper lymphocytes may continue to propagate iLTS.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:177-186, 2019.

Interferon-γ Treatment of Human Laryngotracheal Stenosis-Derived Fibroblasts

Importance

Laryngotracheal stenosis (LTS) is a fibroproliferative disorder of the glottis, subglottis, and trachea. In models of fibrosis from other organ systems, the CD4+ T-cell response has been shown to regulate extracellular matrix deposition. Specifically, helper T cell 2 (TH2) promotes fibrosis, whereas TH1 and associated cytokines have been shown to be antifibrotic. However, this antifibrotic effect of the TH1 response has not been demonstrated in LTS.

Objective

To determine whether the TH1 cytokine interferon-γ inhibits the function of LTS-derived fibroblasts in vitro.

Design, Setting, and Participants

This in vitro controlled study included 6 patients with iatrogenic LTS undergoing routine surgical subglottic and tracheal dilation at a single institution. Fibroblasts were isolated from biopsy specimens of laryngotracheal scar and normal-appearing trachea. The presence of fibroblasts was confirmed by an immunohistochemical analysis. Laryngotracheal stenosis-derived fibroblasts were treated with interferon-γ and compared with untreated controls (2 sets of untreated, LTS-derived fibroblasts [media did not contain interferon-γ]) and normal airway fibroblasts (fibroblasts isolated from normal trachea). Data were collected from August 2015 through June 2016.

Interventions

Treatment with interferon-γ, 10 ng/mL.

Main Outcomes and Measures

Cellular proliferation, fibrosis gene expression (using quantitative reverse transcription polymerase chain reaction analysis), soluble collagen, and cellular histologic features were assessed.

Results

Among the 6 patients (6 women; mean [SD] age, 38.3 [17.2] years), LTS-derived fibroblast proliferation was reduced in patients who received interferon-γ treatment compared with untreated controls on days 3 (mean difference, -6515 cells; 95% CI, -10 630 to -2600 cells) to 6 (mean difference, -47 521 cells; 95% CI, -81 285 to -13 757 cells). Interferon-γ treatment reduced collagen types I and III gene expression by 86% and 68%, respectively, and resulted in lower total collagen production (10.94 vs 14.89 μg/mL). In addition, interferon-γ treatment resulted in a 32% reduction in expression of transforming growth factor β in LTS-derived fibroblasts.

Conclusions and Relevance

Interferon-γ reduced proliferation, soluble collagen production, and collagen expression in LTS-derived fibroblasts while also reducing the expression of the profibrotic cytokine transforming growth factor β. These findings suggest that therapeutics aimed at increasing interferon-γ and the TH1 response could attenuate LTS.

Association of Transoral Robotic Surgery With Short-term and Long-term Outcomes and Costs of Care in Oropharyngeal Cancer Surgery

Importance

The treatment of oropharyngeal cancer has undergone a paradigm shift in the past 2 decades, with an increase in the use of nonoperative treatment owing to poor functional outcomes associated with traditional surgical approaches. Transoral robotic surgery (TORS) allows surgical resection of oropharyngeal cancer (OPC) with less morbidity through a minimally invasive approach.

Objective

To investigate the relationship among TORS and short- and long-term outcomes and costs in surgically treated patients with OPC.

Design, Setting, and Participants

Retrospective cross-sectional analysis of 3573 patients who underwent an ablative procedure for OPC in 2010 to 2012 using the MarketScan Commercial Claim and Encounters database.

Main Outcomes and Measures

The association between TORS and short- and long-term outcomes, length of hospitalization, and treatment-related costs was analyzed using descriptive statistics and multivariate regression modeling.

Results

Transoral robotic surgery was performed in 304 surgical cases (8.5%); 94.7% of patients were 40 to 64 years old, and 70.7% were male. The use of TORS increased from 4.1% of surgical cases in 2010 to 13.2% of surgical cases in 2012. Patients who underwent TORS had a lower rate of tracheotomy during treatment (3.9% vs 11.4%), and posttreatment gastrostomy tube use (21.9% vs 34.2%), compared with patients undergoing non-TORS procedures. On multivariate analysis, TORS was not associated with significant differences in postoperative complications or length of hospitalization. There was no significant difference in the odds of receiving postoperative radiation therapy between patients who underwent TORS and those who did not; however, among patients receiving radiation therapy, chemoradiation was significantly less likely following TORS (odds ratio [OR], 0.52; 95% CI, 0.29-0.90). TORS was associated with significantly decreased odds of posttreatment gastrostomy (OR, 0.54; 95% CI. 0.30-0.95) and tracheostomy during treatment (OR, 0.17; 95% CI, 0.06-0.55) at 1 year, and was associated with significantly decreased overall treatment-related costs of care (mean incremental cost, -$22 724).

Conclusions and Relevance

The use of TORS for surgical resection of OPC is increasing in the United States and is associated with significantly lower use of adjuvant chemoradiation, late gastrostomy and tracheostomy dependence, and lower overall treatment-related costs of care. These data have implications for discussions of value in OPC care at a time of health care reform.

Metabolic variations in normal and fibrotic human laryngotracheal-derived fibroblasts: A Warburg-like effect

OBJECTIVES/HYPOTHESIS

Laryngotracheal stenosis (LTS) is a chronic fibrotic disease characterized by fibroblast proliferation, collagen deposition, and matrix remodeling in the lamina propria of the larynx and/or trachea. Current medical therapies are limited by a poor understanding of the effector cell's (fibroblasts) cellular biology and metabolism. The purpose of this study was to compare cellular proliferation, function, and metabolism between normal and LTS-derived fibroblasts in vitro. We hypothesize that LTS-derived fibroblasts will demonstrate aberrant behavior with faster proliferation, increased collagen production, and altered metabolic allocation compared with normal fibroblasts.

STUDY DESIGN

In vitro comparative analysis.

METHODS

Human biopsies of normal and iatrogenic LTS tissue (n = 7) were obtained, and fibroblasts were isolated and cultured in vitro. Cellular proliferation, cellular histology, gene expression, and metabolic analyses were performed. Statistical analyses comparing normal and scar-derived fibroblasts were performed.

RESULTS

LTS fibroblast proliferation rate, cellular surface area, and collagen-1 expression were increased compared to normal fibroblasts. Cellular metabolic analysis of LTS-derived fibroblasts demonstrated reduced oxidative phosphorylation and increased glycolysis/oxidative phosphorylation ratio compared with normal fibroblasts.

CONCLUSIONS

Human iatrogenic LTS-derived fibroblasts demonstrated aberrant behavior when compared with normal fibroblasts. A Warburg-like effect was revealed, suggesting human iatrogenic LTS fibroblasts drive their proliferation with aerobic glycolysis. The distinct metabolism suggests metabolic inhibitors could reduce fibroblast hyperplasia and hypertrophy in LTS and fibrosis in general.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:E107-E113, 2017.

Changes in Unknown Primary Squamous Cell Carcinoma of the Head and Neck at Initial Presentation in the Era of Human Papillomavirus

IMPORTANCE

The presence of human papillomavirus (HPV) in unknown primary squamous cell carcinoma (UPSCC) of the head and neck at initial presentation focuses the investigation for the primary tumor on the oropharynx. The trends, frequency, and detection rate of UPSCCs have not been evaluated in the context of HPV tumor status.

OBJECTIVES

To determine the frequency of UPSCC over time and to evaluate the proportion of HPV-positive UPSCCs.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective, single-institutional case series of patients diagnosed with UPSCC and evaluated at the Johns Hopkins Hospital from January 1, 2005, to June 1, 2014. Human papillomavirus tumor status was determined by p16 immunohistochemical analysis and/or high-risk HPV DNA by in situ hybridization as clinically available.

MAIN OUTCOMES AND MEASURES

Number and clinical characteristics of UPSCC cases over time.

RESULTS

Eighty-four UPSCC cases were eligible for analysis. The mean age of the patients was 57.3 years (range 29-80 years), and 88.1% (n = 74) were male. The frequency of UPSCC increased significantly over time (P for trend = .01) and was significantly higher during later calendar periods (14 cases during 2005-2008 vs 39 cases during 2012-2014, P = .03). A total of 69 cases (90.7%) with available HPV tumor status were HPV-positive. The patients with HPV-positive UPSCC were significantly more likely to be male (91% vs 42.9%, P = .005) and younger (56.1 vs 67.7 years, P = .002) than the HPV-negative patients with UPSCC. The overall primary tumor site detection rate was 59.3% (n = 48). There was a nonsignificant increase in the detection rate from calendar periods 2005-2008 to 2012-2014 (50.0% vs 64.9%, P = .38). Since transoral robotic surgery was adopted in the diagnostic evaluation of UPSCC in 2011, a nonsignificant increase in the detection of primary tumors was observed (53.8% vs 64.3%, P = .34).

CONCLUSIONS AND RELEVANCE

The frequency of UPSCC has increased significantly in recent calendar periods, and most cases are HPV-positive. As expected, patients with HPV-positive UPSCC tend to be male and younger.

Fetal alcohol spectrum disorders: knowledge and screening practices of university hospital medical students and residents

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is the leading cause of preventable intellectual disabilities in the United States and a significant public health issue.

OBJECTIVES

The purpose of this study is to evaluate the knowledge and screening practices of pre-clinical medical students and clinical providers on FAS, FASD, and alcohol consumption.

METHODS

A short survey sent to medical students and residents on the campus of a large medical school and university hospital.

RESULTS

On the survey of clinical providers, 38% of respondents stated they always survey pregnant women about their alcohol consumption, 34% stated they always screen patients planning to get pregnant, and 9% screen women of childbearing age. There were a significant percentage of providers who never screen women. When questioned regarding safe amounts of alcohol consumption during pregnancy, 69% of pre-clinical medical students and 67% of clinical providers stated there is no safe amount of alcohol consumption. Clinical providers were much more likely to correctly select the facial features necessary for the diagnosis (p-value < 0.01).

CONCLUSIONS

Significant differences exist in the knowledge and screening practices of these different healthcare providers and trainees. Future interventions should seek to improve knowledge on FAS, FASD, and alcohol consumption, in order for practitioners to be more consistent with national guidelines and the Surgeon General recommendations.