Age-specific nasal epithelial responses to SARS-CoV-2 infection.

Children infected with SARS-CoV-2 rarely progress to respiratory failure. However, the risk of mortality in infected people over 85 years of age remains high. Here we investigate differences in the cellular landscape and function of paediatric (<12 years), adult (30-50 years) and older adult (>70 years) ex vivo cultured nasal epithelial cells in response to infection with SARS-CoV-2. We show that cell tropism of SARS-CoV-2, and expression of ACE2 and TMPRSS2 in nasal epithelial cell subtypes, differ between age groups. While ciliated cells are viral replication centres across all age groups, a distinct goblet inflammatory subtype emerges in infected paediatric cultures and shows high expression of interferon-stimulated genes and incomplete viral replication. In contrast, older adult cultures infected with SARS-CoV-2 show a proportional increase in basaloid-like cells, which facilitate viral spread and are associated with altered epithelial repair pathways. We confirm age-specific induction of these cell types by integrating data from in vivo COVID-19 studies and validate that our in vitro model recapitulates early epithelial responses to SARS-CoV-2 infection.

Lentiviral expression of wild-type LAMA3A restores cell adhesion in airway basal cells from children with epidermolysis bullosa.

The hallmark of epidermolysis bullosa (EB) is fragile attachment of epithelia due to genetic variants in cell adhesion genes. We describe 16 EB patients treated in the ear, nose, and throat department of a tertiary pediatric hospital linked to the United Kingdom's national EB unit between 1992 and 2023. Patients suffered a high degree of morbidity and mortality from laryngotracheal stenosis. Variants in laminin subunit alpha-3 (LAMA3) were found in 10/15 patients where genotype was available. LAMA3 encodes a subunit of the laminin-332 heterotrimeric extracellular matrix protein complex and is expressed by airway epithelial basal stem cells. We investigated the benefit of restoring wild-type LAMA3 expression in primary EB patient-derived basal cell cultures. EB basal cells demonstrated weak adhesion to cell culture substrates, but could otherwise be expanded similarly to non-EB basal cells. In vitro lentiviral overexpression of LAMA3A in EB basal cells enabled them to differentiate in air-liquid interface cultures, producing cilia with normal ciliary beat frequency. Moreover, transduction restored cell adhesion to levels comparable to a non-EB donor culture. These data provide proof of concept for a combined cell and gene therapy approach to treat airway disease in LAMA3-affected EB.

Pedicled pericardial patch in tracheal reconstruction in children - Novel technique to provide vascularized tissue for salvaging difficult airways.

BACKGROUND: Management of large central airway defects are often complex. Children who present with these defects have multiple co-morbidities or have had previous surgeries. Surgical options include various tissue cover for these defects without longer term benefits. Vascularized autologous pericardial patch offers a better solution to these defects by providing vascularity and potential for remodelling in future. METHODS: 41 children (M:F of 24:17) were operated for large trachea-bronchial defects between January 2015 and August 2022. The median age of was 12 months with median weight of 8.9 kg (IQR 3.3 kg-17.7 kg) Causes leading to the central tracheal defect include failed repair of previous trachea-oesophageal fistula (TOF) (n = 21) and acquired fistula due to button battery injury (n = 11). Surgical repair consisted of autologous pedicled pericardial patch repair for the airway defect under cardiopulmonary bypass. RESULTS: There were two operative deaths related to extensive sepsis and necrosis of reconstructed trachea. Four children had further reoperation with additional patch. Bronchoscopy was used as surveillance in all these children, with use of airway stents (biodegradable stent) in 9 children. The median ventilation time was 8 days, with tracheostomy being needed in 5 for long term support. CONCLUSIONS: Autologous pericardial patch is a versatile technique and can be used to salvage large tracheal defects when other method have failed or not feasible. Tracheomalacia at the site of repair could be managed with biodegradable stents. Vascularity and ciliary function of the patch still needs to be evaluated.

Open and Thoracoscopic Aortopexy for Airway Malacia in Children: 15 Year Single Centre Experience.

OBJECTIVES: The objective was to report and analyse the characteristics and results of open aortopexy and thoracoscopic aortopexy for the treatment of airway malacia in a paediatric population. METHODS: We report a retrospective consecutive case series of paediatric patients undergoing aortopexy for the treatment of airway malacia at a quaternary referral centre between December 2006 and January 2021. Outcome measures included days to extubation, continued need for non-invasive ventilation, further intervention in the form of tracheostomy and death. RESULTS: 169 patients underwent aortopexy: 147 had open procedures (135 via median/limited median sternotomy and 12 thoracotomy) and 22 thoracoscopic. Mean follow up was 8.46 yrs (range 1-20 yrs). Most common site of airway malacia was the trachea (n = 106, 62.7 %), and 48 (28.4 %) had additional involvement at the bronchi with tracheobronchomalacia (TBM). 15 (8.9 %) had bronchomalacia (BM) only. Incidence of bronchial disease was lower in the thoracoscopic than open group (13.6 % vs 40.82 %; p < 0.0001). Mean time to extubation was 1.45 days, 2.59 days, 5.23 days in tracheomalacia, TBM and BM groups, respectively (p = 0.0047). Mean time to extubation was 1.35 days, 2 days, 3.67 days, and 5 days in patients with external vascular compression, TOF/OA, primary airway malacia, and laryngeal reconstruction, respectively (p = 0.0002). There were 21 deaths across the cohort, and all were in the open group. 71.4 % (n = 15) had bronchial involvement of their airway malacia. CONCLUSIONS: Open and thoracoscopic aortopexy are effective treatments for airway malacia in children. We have identified that involvement of the bronchi is a risk factor for adverse outcomes, and the optimum treatment for this patient cohort is still debatable. LEVEL OF EVIDENCE: IV. TYPE OF STUDY: Retrospective Study.

Revisiting the Great Ormond Street Hospital protocol for ward decannulation of children with tracheostomy.

INTRODUCTION: Tracheostomy decannulation is an important and final step in managing patients once the underlying issue requiring a tracheostomy resolves. However, no consensus exists on the optimal method to decannulate a paediatric patient. We revisit the Great Ormond Street Hospital (GOSH) tracheostomy decannulation protocol, a 5-day process involving downsizing the tracheostomy tube, capping, and observation, to evaluate its effectiveness and assess if changes to the protocol are required. METHOD: This is a retrospective study, reviewing patient records between April 2018 and April 2023 from a single quaternary care centre. Data extracted include comorbidities, age at the time of decannulation, duration of tracheostomy, reason for tracheostomy insertion, whether a decannulation attempt was successful or not, and the timings of decannulation failure. RESULTS: 66 patients that met the selection criteria underwent a decannulation trial between April 2018 and April 2023. 32 patients were male, and 34 patients were female. Age at attempted decannulations ranged from 1 year to 18 years, with an average age of 6.1 years. There were a total of 93 attempts at decannulation, with 51 (54.8%) successful attempts, 35 (56.5%) first decannulation attempt successes, and 42 (45.2%) unsuccessful attempts. 17 patients had 2 attempts at decannulation, and 4 patients had 3 or more attempts at decannulation. Of the unsuccessful attempts, patients mostly failed on capping of the tracheostomy tube with 33 failures (35.5%). CONCLUSION: The GOSH protocol achieved similar success rates to comparable protocols. The protocol's multi-step approach provides thorough evaluation and support for patients during the decannulation process, and its success on a complex patient cohort supports its continued use.

Tracheal Resection for Critical Airway Obstruction in Morquio A Syndrome.

Introduction: The primary cause of death in Morquio A syndrome (mucopolysaccharidosis (MPS) IVA) is airway obstruction, brought about by an inexorable and pathognomonic multilevel airway tortuosity, buckling, and obstruction. The relative pathophysiological contributions of an inherent cartilage processing defect versus a mismatch in longitudinal growth between the trachea and the thoracic cage are currently a subject of debate. Enzyme replacement therapy (ERT) and multidisciplinary management continue to improve life expectancy for Morquio A patients by slowing many of the multisystem pathological consequences of the disease but are not as effective at reversing established pathology. An urgent need has developed to consider alternatives to palliation of progressive tracheal obstruction to preserve and maintain these patients' hard-won good quality of life, as well as to facilitate spinal and other required surgery. Case Report. Following multidisciplinary discussion, transcervical tracheal resection with limited manubriectomy was successfully performed, without the need for cardiopulmonary bypass, in an adolescent male on ERT with the severe airway manifestations of Morquio A syndrome. His trachea was found to be under significant compressive forces at surgery. On histology, chondrocyte lacunae appeared enlarged, but intracellular lysosomal staining and extracellular glycosaminoglycan staining was comparable to control trachea. At 12 months, this has resulted in a significant improvement in respiratory and functional status, with corresponding enhancement to his quality of life. Conclusion: This addressing of tracheal/thoracic cage dimension mismatch represents a novel surgical treatment approach to an existing clinical paradigm and may be useful for other carefully selected individuals with MPS IVA. Further work is needed to better understand the role and optimal timing of tracheal resection within this patient cohort so as to individually balance considerable surgical and anaesthetic risks against the potential symptomatic and life expectancy benefits.

Cell-intrinsic differences between human airway epithelial cells from children and adults.

The airway epithelium is a protective barrier that is maintained by the self-renewal and differentiation of basal stem cells. Increasing age is a principle risk factor for chronic lung diseases, but few studies have explored age-related molecular or functional changes in the airway epithelium. We retrieved epithelial biopsies from histologically normal tracheobronchial sites from pediatric and adult donors and compared their cellular composition and gene expression profile (in laser capture-microdissected whole epithelium, fluorescence-activated cell-sorted basal cells, and basal cells in cell culture). Histologically, pediatric and adult tracheobronchial epithelium was similar in composition. We observed age-associated changes in RNA sequencing studies, including higher interferon-associated gene expression in pediatric epithelium. In cell culture, pediatric cells had higher colony formation ability, sustained in vitro growth, and outcompeted adult cells in a direct competitive proliferation assay. Our results demonstrate cell-intrinsic differences between airway epithelial cells from children and adults in both homeostatic and proliferative states.

Lessons learned from pre-clinical testing of xenogeneic decellularized esophagi in a rabbit model.

Decellularization of esophagi from several species for tissue engineering is well described, but successful implantation in animal models of esophageal replacement has been challenging. The purpose of this study was to assess feasibility and applicability of esophageal replacement using decellularized porcine esophageal scaffolds in a new pre-clinical model. Following surgical replacement in rabbits with a vascularizing muscle flap, we observed successful anastomoses of decellularized scaffolds, cues of early neovascularization, and prevention of luminal collapse by the use of biodegradable stents. However, despite the success of the surgical procedure, the long-term survival was limited by the fragility of the animal model. Our results indicate that transplantation of a decellularized porcine scaffold is possible and vascular flaps may be useful to provide a vascular supply, but long-term outcomes require further pre-clinical testing in a different large animal model.

Laryngeal reinnervation for paediatric vocal cord palsy: a systematic review.

OBJECTIVE: This systematic review aims to provide an overview of the current evidence-base for paediatric surgical reinnervation in unilateral and bilateral vocal fold palsies in clinical practice. We aim to assess patient demographics, surgical technique and pre- and post-operative outcome measures. METHODS: A systematic literature review was performed and reported according to international PRISMA recommendations. A comprehensive search of PubMed, Embase, and Cochrane CENTRAL databases for relevant publications for all available dates with appropriate MESH search criteria was performed. Articles were categorised by four authors independently. A pooled summative analysis was carried out to allow review of demographic and outcome data. RESULTS: Our systematic PRISMA approach resulted in 19 papers being selected for inclusion and analysis with 179 patients undergoing reinnervation (153 unilateral, 26 bilateral). The youngest patient was 1.9 years. Iatrogenic injury to recurrent laryngeal nerve most common aetiology (65.4% and 19.2% of unilateral and bilateral vocal fold palsies, respectively). Patent ductus arteriosus ligation was the single most common procedure resulting in unilateral vocal fold palsies (43.1% of cases). Statistically significant improvements in subjective and objective outcomes for both voice and swallowing were seen. Meta-analysis was able to be performed on the particularly evident improvements in GRBAS score and Maximum Phonation Time (MPT). GRBAS scores improved by 3.64 (p < 0.01, 95% CI 2.65 to 4.63). MPT showed a statistically significant improvement of 5.26 s (p < 0.05, 95% CI 4.28 to 6.24). No major complications were reported. CONCLUSION: The current published evidence on one-hundred and seventy-nine paediatric surgical reinnervation procedures demonstrates its role as a safe and effective treatment for both unilateral and bilateral vocal fold palsies. Anatomically it has been shown to improve vocal fold tone, bulk and position. Both post-operative voice and swallowing outcomes show improvement as well as associated quality of life measures.

Use of Simulation to Visualize Healthcare Worker Exposure to Aerosol in the Operating Room.

SUMMARY STATEMENT: Simulation resources offer an opportunity to highlight aerosol dispersion within the operating room environment. We demonstrate our methodology with a supporting video that can offer operating room teams support in their practical understanding of aerosol exposure and the importance of personal protective equipment.

Local and systemic responses to SARS-CoV-2 infection in children and adults.

It is not fully understood why COVID-19 is typically milder in children1-3. Here, to examine the differences between children and adults in their response to SARS-CoV-2 infection, we analysed paediatric and adult patients with COVID-19 as well as healthy control individuals (total n = 93) using single-cell multi-omic profiling of matched nasal, tracheal, bronchial and blood samples. In the airways of healthy paediatric individuals, we observed cells that were already in an interferon-activated state, which after SARS-CoV-2 infection was further induced especially in airway immune cells. We postulate that higher paediatric innate interferon responses restrict viral replication and disease progression. The systemic response in children was characterized by increases in naive lymphocytes and a depletion of natural killer cells, whereas, in adults, cytotoxic T cells and interferon-stimulated subpopulations were significantly increased. We provide evidence that dendritic cells initiate interferon signalling in early infection, and identify epithelial cell states associated with COVID-19 and age. Our matching nasal and blood data show a strong interferon response in the airways with the induction of systemic interferon-stimulated populations, which were substantially reduced in paediatric patients. Together, we provide several mechanisms that explain the milder clinical syndrome observed in children.

Super-resolution Reconstruction MRI Application in Fetal Neck Masses and Congenital High Airway Obstruction Syndrome.

OBJECTIVE: Reliable airway patency diagnosis in fetal tracheolaryngeal obstruction is crucial to select and plan ex utero intrapartum treatment (EXIT) surgery. We compared the clinical utility of magnetic resonance imaging (MRI) super-resolution reconstruction (SRR) of the trachea, which can mitigate unpredictable fetal motion effects, with standard 2-dimensional (2D) MRI for airway patency diagnosis and assessment of fetal neck mass anatomy. STUDY DESIGN: A single-center case series of 7 consecutive singleton pregnancies with complex upper airway obstruction (2013-2019). SETTING: A tertiary fetal medicine unit performing EXIT surgery. METHODS: MRI SRR of the trachea was performed involving rigid motion correction of acquired 2D MRI slices combined with robust outlier detection to reconstruct an isotropic high-resolution volume. SRR, 2D MRI, and paired data were blindly assessed by 3 radiologists in 3 experimental rounds. RESULTS: Airway patency was correctly diagnosed in 4 of 7 cases (57%) with 2D MRI as compared with 2 of 7 cases (29%) with SRR alone or paired 2D MRI and SRR. Radiologists were more confident (P = .026) in airway patency diagnosis when using 2D MRI than SRR. Anatomic clarity was higher with SRR (P = .027) or paired data (P = .041) in comparison with 2D MRI alone. Radiologists detected further anatomic details by using paired images versus 2D MRI alone (P < .001). Cognitive load, as assessed by the NASA Task Load Index, was increased with paired or SRR data in comparison with 2D MRI. CONCLUSION: The addition of SRR to 2D MRI does not increase fetal airway patency diagnostic accuracy but does provide improved anatomic information, which may benefit surgical planning of EXIT procedures.

Micro-CT Imaging of Pediatric Thyroglossal Duct Cysts: A Prospective Case Series.

Objectives: To determine the feasibility of micro-CT as a high-resolution 3D imaging tool for thyroglossal duct cysts and to evaluate its role augmenting traditional histopathological examination of resected specimens. Methods: A single centre, prospective case series of consecutive children undergoing excision of a thyroglossal duct cyst was performed at a quaternary paediatric referral hospital in the United Kingdom. Consecutive children listed for excision of a thyroglossal duct cyst whose parents agreed to participate were included and there were no exclusion criteria. Results: Surgically excised thyroglossal duct cyst or remnant specimens from five patients (two males, three females) were examined using micro-CT alongside traditional histopathological examination. In all cases, micro-CT imaging was able to demonstrate 3D imaging datasets of the specimens successfully and direct radio-pathological comparisons were made (Figures 1-5, Supplementary Video 1). Conclusions: The study has shown the feasibility and utility of post-operative micro-CT imaging of thyroglossal duct cysts specimens as a visual aid to traditional histopathological examination. It better informs the pathological specimen sectioning using multi-planar reconstruction and volume rendering tools without tissue destruction. In the complex, often arborised relationship between a thyroglossal duct cyst and the hyoid, micro-CT provides valuable image plane orientation and indicates proximity of the duct to the surgical margins. This is the first case series to explore the use of micro-CT imaging for pediatric thyroglossal duct specimens and it informs future work investigating the generalizability of micro-CT imaging methods for other lesions, particularly those from the head and neck region where precisely defining margins of excision may be challenging.

Early diagnosis of kala-azar in Bangladesh: Findings from a population based mixed methods research informing the post-elimination era.

BACKGROUND: Global annual reports of visceral leishmaniasis or kala-azar ("black fever") reduced from 200,000 cases in 2012 to 23,804 in 2015. India, Bangladesh and Nepal reported 80% of the global cases in 2012, but 39% in 2015. We sought to identify major amenable barriers to early diagnosis of kala-azar in peripheral areas of Mymensingh district, an area of Bangladesh that was highly endemic for kala-azar. METHODS: We conducted sequential exploratory mixed methods research. Qualitative data were first derived from in-depth interviews and focus group discussions among 29 patients diagnosed with kala-azar, their families, and neighbours. Preliminary results from qualitative analysis were used to design a structured questionnaire, which was administered to collect data on the processes leading to the diagnosis of kala-azar from 102 patients. Qualitative and quantitative data were integrated consistent with the chronology for kala-azar patients seeking care. The study was conducted from September 2011 to May 2012 in Fulbaria and Gaffargaon sub-districts of Mymensingh. RESULTS: The median delay from fever onset to confirmatory diagnosis of kala-azar was 60 days, with 38% of the cases diagnosed within 30 days. Public health facilities and Gaffargaon sub-district achieved high proportions of early diagnosis. Individual barriers to early diagnosis were low awareness of symptoms and treatment facilities, poverty, and traditional beliefs. Other factors were the remoteness of health care centres, wet season transport difficulty, mis-diagnosis as typhoid, limited availability of rK-39 testing at the community level, and the inclusion of splenomegaly in the case definition. CONCLUSIONS: Targeted community awareness campaigns appropriate for underprivileged communities will increase care seeking and consequently diagnosis. Improved diagnostic guidelines and a strong referral chain for kala-azar will accelerate diagnosis. These steps will contribute significantly to the National Kala-azar Elimination Program of Bangladesh, especially during the post-elimination era.

Subglottic ectopic thymus mimicking airway haemangioma.

Subglottic haemangioma presents as progressive obstruction in the neonatal and infantile airway, with a soft lesion seen during endoscopy. Diagnosis is based on macroscopic findings, biopsy is not usually performed and propranolol is first-line treatment. In contrast, ectopic thymus is a rare differential diagnosis for subglottic mass made by histopathological examination after excision or autopsy. In this article, we present a case of an infant with a subglottic lesion with endoscopic features consistent with haemangioma. After initial clinical response to propranolol, the patient represented with progressive stridor no longer responding to therapy. Open excision of the lesion was performed, and histopathology revealed ectopic thymus tissue. In this case, ectopic thymus tissue mimicked the presentation of subglottic haemangioma, and confirmation bias persisted due to an apparent initial clinical response to treatment with propranolol. In cases of subglottic mass refractory to medical treatment, excision of the lesion should be considered.