ABSTRACT
OBJECTIVES: Animal models for laryngotracheal stenosis (LTS) are critical to understand underlying mechanisms and study new therapies. Current animal models for LTS are limited by small airway sizes compared to human. The objective of this study was to develop and validate a novel, large animal ovine model for LTS. METHODS: Sheep underwent either bleomycin-coated polypropylene brush injury to the subglottis (n = 6) or airway stent placement (n = 2) via suspension microlaryngoscopy. Laryngotracheal complexes were harvested 4 weeks following injury or stent placement. For the airway injury group, biopsies (n = 3 at each site) were collected of tracheal scar and distal normal regions, and analyzed for fibrotic gene expression. Lamina propria (LP) thickness was compared between injured and normal areas of trachea. RESULTS: No mortality occurred in sheep undergoing airway injury or stent placement. There was no migration of tracheal stents. After protocol optimization, LP thickness was significantly increased in injured trachea (Sheep #3: 529.0 vs. 850.8 um; Sheep #4: 933.0 vs. 1693.2 um; Sheep #5: 743.7 vs. 1378.4 um; Sheep #6: 305.7 vs. 2257.6 um). A significant 62-fold, 20-fold, 16-fold, 16-fold, and 9-fold change of COL1, COL3, COL5, FN1, and TGFB1 was observed in injured scar specimen relative to unaffected airway, respectively. CONCLUSION: An ovine LTS model produces histologic and transcriptional changes consistent with fibrosis seen in human LTS. Airway stent placement in this model is safe and feasible. This large airway model is a reliable and reproducible method to assess the efficacy of novel LTS therapies prior to clinical translation. LEVEL OF EVIDENCE: N/A Laryngoscope, 2024.
ABSTRACT
OBJECTIVE: To present a comprehensive flow cytometry panel for idiopathic subglottic stenosis (iSGS). STUDY DESIGN: Controlled ex vivo cohort study. SETTING: Tertiary care academic hospital in a metropolitan area. METHODS: Flow cytometry and single-cell RNA sequencing were performed on 9 paired normal and scar tissue samples from iSGS patients. Flow cytometry was used to assess the presence of myeloid (CD11b, CD14, CD15, Siglec8), lymphoid (CD3, CD4, CD8, gamma delta [γδ], FOXP3), endothelial (CD31), fibroblast (CD90, SMA), and epithelial (CD326, CK5) markers. RESULTS: On flow cytometry, iSGS scar is characterized by an increased presence of myeloid, lymphoid, endothelial, and fibroblast cell types, but a decreased presence of epithelial cells. In the myeloid lineage, iSGS scar samples demonstrated increased CD11b+ monocytes (P < .001), Siglec8+ eosinophils (P = .03), and CD14+ monocytes (P = .02). In the lymphoid lineage, iSGS scar demonstrated increased CD3+ T-cells (P < .001), CD4+ helper T-cells (P < .001), γδ+ T-cells (P < .001), and FOXP3+ regulatory T-cells (P = .002). iSGS scar exhibited specific increases in CD90+ (P = .04) and SMA+ (P < .001) fibroblasts but decreased CD326+ (E-cadherin) epithelial cells (P = .01) relative to normal samples. CONCLUSION: We present a comprehensive flow cytometry panel for iSGS. This flow panel may serve as a common platform among airway scientists to elucidate the cellular mechanisms underpinning iSGS and other upper airway pathologies. Scar iSGS samples demonstrate a distinct cellular profile relative to normal iSGS specimens, exhibiting increased fibroblast, endothelial, and inflammatory cell types but decreased epithelium.
ABSTRACT
OBJECTIVE: To describe iatrogenic laryngeal injury and identify its risk factors in recurrent respiratory papillomatosis (RRP) patients receiving surgical care. STUDY DESIGN: Case-control. SETTING: Tertiary care academic hospital in a metropolitan area. METHODS: Charts of patients with RRP seen at our institution from January 2002 to December 2022 were reviewed. Patients were separated into 2 cohorts based upon whether they experienced any form of iatrogenic laryngeal injury-including anterior commissure synechiae, vocal cord scar, reduced vocal fold pliability, vocal fold motion impairment, and glottic and/or subglottic stenosis. Adjusted logistic regressions were performed to identify factors associated with iatrogenic laryngeal injury. RESULTS: Of 199 RRP patients, 133 (66.8%) had identifiable iatrogenic laryngeal injury. The most common injuries were anterior commissure synechiae (n = 67; 50.4%) and reduced vocal fold pliability (n = 54; 40.6%). On a multivariate logistic regression, patients with diabetes mellitus (adjusted odds ratio [aOR] [95% confidence interval [CI]]: 2.99 [1.02, 8.79]; P = .04) and who received at least 10 surgeries lifetime (aOR [95% CI]: 14.47 [1.70, 123.19]; P = .01) were at increased risk for iatrogenic laryngeal injury, whereas receiving less than 5 surgeries (aOR [95% CI]: 0.21 [0.09, 0.51]; P < .001) was found to be protective. When treating the lifetime number of surgeries as a continuous variable, a greater number of surgeries was a significant risk factor for iatrogenic laryngeal injury (aOR [95% CI]: 1.32 [1.14, 1.53]; P < .001). CONCLUSION: These results suggest the importance of strict glucose control for diabetic patients receiving RRP surgical care, and emphasize the clinical need to identify medical therapies to decrease RRP surgical frequency for patients.