Identifying Molecular Pathophysiology and Potential Therapeutic Options in Iatrogenic Tracheal Stenosis.

INTRODUCTION: While most patients with iatrogenic tracheal stenosis (ITS) respond to endoscopic ablative procedures, approximately 15% experience a recalcitrant, recurring disease course that is resistant to conventional management. We aimed to explore genetic profiles of patients with recalcitrant ITS to understand underlying pathophysiology and identify novel therapeutic options. METHODS: We collected 11 samples of granulation tissue from patients with ITS and performed RNA sequencing. We identified the top 10 most highly up- and down-regulated genes and cellular processes that these genes corresponded to. For the most highly dysregulated genes, we identified potential therapeutic options that favorably regulate their expression. RESULTS: The dysregulations in gene expression corresponded to hyperkeratinization (upregulation of genes involved in keratin production and keratinocyte differentiation) and cellular proliferation (downregulation of cell cycle regulating and pro-apoptotic genes). Genes involved in retinoic acid (RA) metabolism and signaling were dysregulated in a pattern suggesting local cellular RA deficiency. Consequently, RA also emerged as the most promising potential therapeutic option for ITS, as it favorably regulated seven of the ten most highly dysregulated genes. CONCLUSION: This is the first study to characterize the role of hyperkeratinization and dysregulations in RA metabolism and signaling in the disease pathophysiology. Given the ability of RA to favorably regulate key genes involved in ITS, future studies must explore its efficacy as a potential therapeutic option for patients with recalcitrant ITS.

Gene expression profiles in COVID-19-associated tracheal stenosis indicate persistent anti-viral response and dysregulated retinol metabolism.

INTRODUCTION: Coronavirus disease 2019 (COVID-19)-associated tracheal stenosis (COATS) may occur as a result of prolonged intubation during COVID-19 infection. We aimed to investigate patterns of gene expression in the tracheal granulation tissue of patients with COATS, leverage gene expression data to identify dysregulated cellular pathways and processes, and discuss potential therapeutic options based on the identified gene expression profiles. METHODS: Adult patients (age ≥ 18 years) presenting to clinics for management of severe, recalcitrant COATS were included in this study. RNA sequencing and differential gene expression analysis was performed with transcriptomic data for normal tracheal tissue being used as a control. The top ten most highly upregulated and downregulated genes were identified. For each of these pathologically dysregulated genes, we identified key cellular pathways and processes they are involved in using Gene Ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) applied via Database for Annotation, Visualization, and Integrated Discovery (DAVID). RESULTS: Two women, aged 36 years and 37 years, were included. The profile of dysregulated genes indicated a cellular response consistent with viral infection (CXCL11, PI15, CCL8, DEFB103A, IFI6, ACOD1, and DEFB4A) and hyperproliferation/hypergranulation (MMP3, CASP14 and HAS1), while downregulated pathways included retinol metabolism (ALDH1A2, RBP1, RBP4, CRABP1 and CRABP2). CONCLUSION: Gene expression changes consistent with persistent viral infection and dysregulated retinol metabolism may promote tracheal hypergranulation and hyperproliferation leading to COATS. Given the presence of existing literature highlighting retinoic acid's ability to favorably regulate these genes, improve cell-cell adhesion, and decrease overall disease severity in COVID-19, future studies must evaluate its utility for adjunctive management of COATS in animal models and clinical settings.

Novel composite trachea grafts using 3-dimensional printing.

Objective: Porcine-derived small intestine submucosa (SIS) extracellular matrix (ECM) surgical patches claim to have greater regenerative properties compared with dermal extracellular matrices. We hypothesized that using SIS-ECM in a bioengineered composite tracheal graft would allow better incorporation into the native tissue. Methods: Two types of size-matched polycaprolactone support scaffolds were designed: rigid and flexible. The SIS-ECM was wrapped around the polycaprolactone supports lining the inside and outside of the graft. The grafts were implanted in 4 Yorkshire pigs, replacing an ∼2 cm segment of native trachea. Airway patency was evaluated with computed tomography scans and explanted grafts were examined grossly and histologically. Results: All animals survived through the immediate postoperative period. Generally, extraluminal examination showed a smooth transition between native and graft without significant volumetric loss. Animals that received the flexible design survived ∼10 days longer than those that received the rigid design; however, severe perianastomotic intraluminal granulation tissue was observed. The rigid design had less significant intraluminal granulation tissue development at the distal anastomosis, but partial dehiscence had occurred at the proximal anastomosis interrupting graft incorporation. Conclusions: The generally good extraluminal graft incorporation in our composite tracheal graft highlights some increased regenerative capabilities of SIS-ECM. However, the presence of intraluminal granulation tissue indicates that its use as an off-the-shelf, unaltered substrate in an airway graft is still not ideal. Further research must be conducted to determine whether a modification of the substrate is possible to enhance luminal airway incorporation and to exert control over the mechanisms responsible for granulation tissue development.

The relapsing polychondritis damage index (RPDAM): Development of a disease-specific damage score for relapsing polychondritis.

OBJECTIVES: Relapsing polychondritis is a rare, multi-systemic and inflammatory condition of unknown origin. We currently lack a core set of measures to assess and follow damage in patients suffering from this condition. Our primary aim was to derive a disease-specific damage measuring tool for relapsing polychondritis, the Relapsing Polychondritis Damage Index (RPDAM). METHODS: We performed an international 4-round multicenter Delphi study during which experts were asked to rate the relevance of potential damage items for relapsing polychondritis (141 items were obtained from a literature review and 12 from expert suggestion), using a Likert Scale. The selection of items for each subsequent round was based on the median rating of each item. RESULTS: Twenty-four experts from 11 nationalities participated in round 1 and 22 in rounds 2, 3 and 4. From the initial 153 potential damage items, 44 items were selected during round 1, 30 items during round 2 and 16 during round 3. During round 4, we refined the index to a total of 17 items referring to ear nose and throat, eye, respiratory, cardiovascular and hematological systems as well as to treatment-related specific damage items. CONCLUSION: We have developed by international consensus a scoring system to assess damage in patients with relapsing polychondritis. Following its validation, the RPDAM may contribute to improve the care of patients suffering from this rare condition as well as to standardize data collection for future clinical trials.

Three-Dimensional-Printed Bioengineered Tracheal Grafts: Preclinical Results and Potential for Human Use.

BACKGROUND: We aimed to develop a process using three-dimensional (3D) printing to create bioengineered tracheal grafts (BETGs) for reconstruction of anterior tracheal defects in a large-animal model (porcine) that would have translational relevance for potential human use. METHODS: Preoperative computed tomographic scans were used to create virtual 3D models of the animal airways. Anatomically scaled tracheal grafts were subsequently developed using 3D-printed polycaprolactone and extracellular matrix. A 4-cm anterior tracheal defect (about 50% of the length of the subject trachea) was surgically created in 4-week-old female Yorkshire pigs and reconstructed using the customized grafts. Gross and microscopic analyses of the grafts were performed. RESULTS: The BETGs were implanted in 7 animals. There was adequate graft-native trachea size match at the operation. The trachea was successfully reconstructed in all cases. Gross examination at autopsy showed a structurally intact, well-incorporated graft. Histologic evaluation showed respiratory mucosal coverage and vascularity of the graft. Five of 7 animals outlived the 3-month study period. The animals had approximately 100% growth during the study period. CONCLUSIONS: We report of a 3D-printed BETG to repair long-segment anterior tracheal defects in a large-animal model. Although the study duration is short, this work presents an efficient strategy for tracheal graft bioengineering with potential translational relevance for human use.

Circumferential Three-Dimensional-Printed Tracheal Grafts: Research Model Feasibility and Early Results.

BACKGROUND: Methods for tracheal graft research have presented persistent challenges to investigators, and three-dimensional (3D)-printed biosynthetic grafts offer one potential development platform. We aimed to develop an efficient research platform for customizable circumferential 3D-printed tracheal grafts and evaluate feasibility and early structural integrity with a large-animal model. METHODS: Virtual 3D models of porcine subject tracheas were generated using preoperative computed tomography scans. Two designs were used to test graft customizability and the limits of the construction process. Designs I and II used 270-degree and 360-degree external polycaprolactone scaffolds, respectively, both encompassing a circumferential extracellular matrix collagen layer. The polycaprolactone scaffolds were made in a fused-deposition modeling 3D printer and customized to the recipient's anatomy. Design I was implanted in 3 pigs and design II in 2 pigs, replacing 4-ring tracheal segments. Data collected included details of graft construction, clinical outcomes, bronchoscopy, and gross and histologic examination. RESULTS: The 3D-printed biosynthetic grafts were produced with high fidelity to the native organ. The fabrication process took 36 hours. Grafts were implanted without immediate complication. Bronchoscopy immediately postoperatively and at 1 week demonstrated patent grafts and appropriate healing. All animals lived beyond a predetermined 1-week survival period. Bronchoscopy at 2 weeks showed significant paraanastomotic granulation tissue, which, along with partial paraanastomotic epithelialization, was confirmed on pathology. Overall survival was 17 to 34 days. CONCLUSIONS: We propose a rapid, reproducible, resource efficient method to develop various anatomically precise grafts. Further graft refinement and strategies for granulation tissue management are needed to improve outcomes.

Reconstruction of Anterior Tracheal Defects Using a Bioengineered Graft in a Porcine Model.

BACKGROUND: Reconstruction of long-segment tracheal defects can be challenging and a suitable tracheal substitute remains lacking. We sought to create a bioengineered tracheal graft to repair such lesions using acellullar bovine dermis extracellular matrix (ECM) and male human mesenchymal stem cells (hMSCs) and implant it in a porcine model. METHODS: hMSCs were seeded on the ECM and incubated for 1 week with chondrogenic factors. An anterior 4 cm × 3 cm defect was surgically created in the trachea of 4-week-old female Yorkshire pigs. The defect was reconstructed using the bioengineered graft (n = 7) or control (n = 3, ECM only). The study duration was 3 months. RESULTS: Survival ranged from 7 days (n = 3) to 3 months (n = 7). Early death was due to graft malacia (n = 1, control), graft infection (n = 1, bioengineered), and pneumonia (n = 1, bioengineered). There was substantial animal growth at 3 months (>200% weight). Surveillance bronchoscopy showed patent airway, mild stenosis, and integration of the graft with the native trachea. On histology, luminal epithelialization and neovascularization with scant submucosa were observed in both the bioengineered graft and control groups. Chondrogenesis was seen only in the bioengineered graft. The neocartilage was less mature and organized compared to native cartilage. SRY immunostain was positive in the neocartilage but not control or native trachea. CONCLUSIONS: We demonstrate the feasibility of the bioengineered graft for reconstruction of long anterior tracheal defects with favorable short-term outcomes. Furthermore, we show its ability to facilitate chondrogenesis, neovascularization, and epithelialization. Importantly, it supported rapid animal growth offering potential solutions for both pediatric and adult applications.

Treatment of Benign Tracheal Stenosis Using Endoluminal Spray Cryotherapy.

Importance: Tracheal stenosis is a debilitating disorder with heterogeneity in terms of disease characteristics and management. Repeated recurrences substantially alter patients' quality of life. There is limited evidence for the use of spray cryotherapy (SCT) in the management of benign airway disease. Objective: To report our early results for the use of SCT in patients with benign tracheal stenosis. Design, Setting, and Participants: Data were extracted from the medical records of a consecutive series of patients with benign airway stenosis secondary to granulomatosis with polyangiitis (GPA) (n = 13), prior tracheotomy or tracheal intubation (n = 8), and idiopathic strictures (n = 5) treated from September 1, 2013, to September 30, 2015, at a tertiary care hospital. Main Outcomes and Measures: Airway narrowing was quantified on a standard quartile grading scale. Response to treatment was assessed by improvement in airway caliber and the time interval for reintervention. Exposures: Delivery of 4 5-second SCT cycles and 2 balloon dilatations. Results: Twenty-six patients (median [range] age, 53 [16-83] years; 20 [77%] female) underwent 48 SCT sessions. Spray cryotherapy was successfully used without any substantial intraoperative or postoperative complications in all patients. In a median (range) follow-up of 11 (1-26) months, all patients had improvement in symptoms. Before the institution of SCT, 23 patients (88%) had grade III or IV stenosis. At the last evaluation after induction of SCT, 4 (15%) had grade III or IV stenosis, with a mean (SD) change of 1.39 (0.51) (P < .001). Patients with GPA required significantly fewer SCT procedures (mean [SD], 1.38 [0.96] vs 2.31 [1.18]; P = .03) during the study period. Conclusions and Relevance: Spray cryotherapy was a safe adjunct modality to accomplish airway patency in patients with benign tracheal stenosis. Although efficacy evidence is limited for SCT, it may be useful for patients who have experienced treatment failure with conventional modalities. Further analysis of this cohort will determine the physiologic durability of the reported short-term changes. Additional trials are warranted for further evaluation of this modality.

Multilevel airway stenosis in patients with granulomatosis with polyangiitis (Wegener's).

OBJECTIVES: To describe the presentation and clinical course of subglottic stenosis (SGS), in particular the development of concurrent airway lesions, in patients with Granulomatosis with Polyangiitis (Wegener's) (GPA). MATERIALS AND METHODS: Retrospective review of clinical data from all patients presenting to our institution from 2000 to 2012 with SGS and GPA. RESULTS: Thirty-five patients were identified. The average age at diagnosis was 33 years old. Eleven patients (31%) presented with SGS as part their initial manifestation of GPA. The remaining patients developed SGS later, at a median of 2.5 years from diagnosis (range 6 months to 14 years). Twelve patients (34%) were noted to have multilevel airway involvement. Seven patients (20%) had documentation of cricoarytenoid joint fixation and vocal cord immobility. This was typically progressive in nature and occurred at an average of two years following the diagnosis of SGS. Six patients (17%) had mid/distal tracheal stenosis and four (11%) had bronchial stenosis. The majority of patients (86%) had evidence of concurrent sinonasal involvement, ten patients (29%) had evidence of otologic involvement and eight (23%) had ocular involvement. CONCLUSIONS: Cricoarytenoid joint fixation and distal stenosis occur not infrequently in patients with GPA and SGS, resulting in progressive multilevel airway stenosis in about one third of patients. It is critical to identify multilevel stenosis when managing the airways of these patients.

Effectiveness of rituximab for the otolaryngologic manifestations of granulomatosis with polyangiitis (Wegener's).

OBJECTIVE: Ear, nose, and throat (ENT) involvement is the most prevalent manifestation of granulomatosis with polyangiitis (Wegener's) (GPA) and correlates with permanent damage and decreased quality of life. Although prior studies have evaluated the efficacy of rituximab (RTX) for granulomatous features of GPA, none have evaluated its efficacy solely for ENT manifestations. We compared the effectiveness of RTX to other therapies for the ENT manifestations of GPA in a large, well-characterized cohort. METHODS: We performed a retrospective analysis of 975 visits from 99 GPA patients seen at a tertiary care ENT practice between 2003 and 2013. At each visit, subjects had a complete ENT examination, with ENT activity assessed by a single expert otolaryngologist. ENT disease activity during the observational period in subjects receiving RTX was compared to subjects receiving all other therapy. RESULTS: In total, 48 subjects had never received RTX and 51 received RTX at least once. There was no active ENT disease during 92.4% of the observational period (days) for subjects receiving RTX, compared with 53.7% of the observational period for subjects not receiving RTX (odds ratio 11.0 [95% confidence interval 5.5­22.0], P < 0.0001). Subjects receiving RTX, compared with those receiving methotrexate, azathioprine, cyclophosphamide, or trimethoprim-sulfamethoxazole, were significantly more likely to have no active ENT disease (P < 0.0001 for each comparison). CONCLUSION: RTX is an effective treatment for ENT manifestations of GPA. Subjects treated with RTX were significantly less likely to have active ENT disease compared with those not receiving RTX. Patients being treated with RTX were 11 times less likely to have active ENT disease than patients being treated with other therapies.

The Relapsing Polychondritis Disease Activity Index: development of a disease activity score for relapsing polychondritis.

OBJECTIVE: The rarity of relapsing polychondritis (RP) has hindered the development of standardized tools for clinical assessment. Here, we describe the development of a preliminary score for disease assessing activity in RP, the Relapsing Polychondritis Disease Activity Index (RPDAI). METHODS: Twenty-seven RP experts participated in an international collaboration. Selection and definition of items for disease activity were established by consensus during a 4-round internet-based Delphi survey. Twenty-six experts assessed the Physician's Global Assessment (PGA) of disease activity on 43 test cases on a 0-100 scale, yielding a total of 1118 PGA ratings. The weight of each item was estimated by multivariate regression models with generalized estimating equation, using PGA as the dependent variable. RESULTS: Experts decided in consensus that the RPDAI should consider the 28-day period before each RPDAI assessment. Inter-rater reliability assessed by the intra-class correlation coefficient for the 1118 PGA ratings was 0.51 (CI95%: 0.41-0.64). The final RPDAI score comprised 27 items with individual weights ranging from 1 to 24 and a maximum theoretical RPDAI score of 265. Correlation between the RPDAI scores calculated based on the weights derived from the final multivariate model, and the 1118 PGA ratings was good (r=0.56, p<0.0001). CONCLUSION: We have developed the first consensus scoring system to measure disease activity in relapsing polychondritis (see www.RPDAI.org for online scoring). This tool will be valuable for improving the care of patients with this rare disease.

Laryngeal manifestations of relapsing polychondritis and a novel treatment option.

OBJECTIVES: Laryngotracheal involvement in relapsing polychondritis (RP) is rare. However, it is one of the most common causes of death in this patient population. We present three patients who primarily presented with laryngeal manifestations of RP and a novel treatment option for bamboo nodules. STUDY DESIGN: Retrospective chart review and comprehensive review of the literature. RESULTS: Two patients first presented to an otolaryngologist because of hoarseness and chronic cough that eventually progressed to dyspnea upon exertion. Laryngeal examination revealed subglottic stenoses. Upon rheumatologic workup both were diagnosed with RP. After treatment with steroids and immunosuppressive drugs, one of the patient's laryngeal symptoms improved, whereas the other required dilation procedures. Neither patient had classic auricular or nasal symptoms upon initial presentation. The third patient was being treated for spasmodic dysphonia and was noted to have bamboo nodules with accompanying dysphonia. Rheumatologic workup revealed RP and systemic treatment ensued. Unfortunately, her symptoms of hoarseness persisted despite systemic treatment. A pulsed-potassium-titanyl-phosphate (KTP) laser was applied to the bilateral bamboo nodules, which eventually caused resolution of her vocal fold lesions and dysphonia. CONCLUSIONS: We present three patients with RP, all of whom sought health care by an otolaryngologist primarily. Awareness of this disease entity and the possibility for early laryngeal involvement is crucial for proper care of those with this life-threatening disease.

Timely airway stenting improves survival in patients with malignant central airway obstruction.

BACKGROUND: The survival of patients with malignant central airway obstruction is very limited. Although airway stenting results in significant palliation of symptoms, data regarding improved survival after stenting for advanced thoracic cancer with central airway obstruction are lacking. METHODS: Fifty patients received a total of 72 airway stents for malignant central airway obstruction over a two-year period at a single institution. The Medical Research Council (MRC) dyspnea scale and Eastern Cooperative Oncology Group (ECOG) performance status were used to divide patients into a poor performance group (MRC = 5, ECOG = 4) and an intermediate performance group (MRC ≤ 4, ECOG ≤ 3). The SPSS version 16.0 (SPSS Inc, Chicago, IL) and Microsoft Excel (Microsoft, Redmond, WA) were used to analyze the data. Survival curves were constructed using the Kaplan-Meier survival analysis method and a log-rank test was used to compare the survival distributions among different groups. RESULTS: Successful patency of the airway was achieved in all patients with no procedure-related mortality. Stenting resulted in significant improvement in MRC and ECOG performance scores (p < 0.01). Significantly improved survival was observed only in patients in the intermediate performance group compared with patients in the poor performance group (p < 0.05). CONCLUSIONS: Airway stenting resulted in significant palliation of symptoms in both groups as evaluated by MRC dyspnea scale and ECOG performance status. Compared with historic controls, a significant survival advantage was seen only in the intermediate performance group. We postulate that timely stenting of the airway, before the morbid complications of malignant central airway obstruction have set in, results in improved survival.

Endoscopic tracheoplasty: segmental tracheal ring resection in a porcine model.

Endoscopic tracheoplasty is used for the relief of airway obstruction because of several benign conditions such as postintubation stenosis, inflammatory disorders such as Wegener granulomatosis, and benign neoplastic processes. Several endoscopic treatment modalities exist for these conditions, all with good initial results. However, recurrence is common and often requires frequent reintervention. Endoscopic segmental tracheal ring resection is a novel therapeutic approach that could potentially provide a durable solution. Endoscopic segmental tracheal ring resection was performed in 3 Yorkshire pigs under general anesthesia. A combination of bipolar cautery and sharp dissection was used to resect 25% to 33% of the circumference of a single tracheal ring. Technical success was achieved in all 3 animals with no intraoperative complications. Full-thickness excision, including the anterior perichondrium, was performed in 1 animal without violation of the pretracheal fascia, with no subcutaneous emphysema or clinically apparent pneumothorax. Average operative time was 31 minutes and estimated blood loss was minimal. Heart rate, oxygen saturation, and peak airway pressures were maintained within normal ranges during the procedure and for the 60-minute postoperative period. Histologic analysis of the resected specimen confirmed complete thickness excision of the segment of tracheal cartilage. Endoscopic tracheoplasty by segmental tracheal ring resection is a safe and feasible technique in a porcine model. Long-term durability could potentially outlast other endoscopic techniques for the treatment of bening tracheal stenosis. Survival studies in a porcine model of tracheal stenosis must be performed to assess the long-term outcomes of this approach.