High efficacy of the F-ATP synthase inhibitor TBAJ-5307 against nontuberculous mycobacteria in vitro and in vivo.

The F1FO-ATP synthase engine is essential for viability and growth of nontuberculous mycobacteria (NTM) by providing the biological energy ATP and keeping ATP homeostasis under hypoxic stress conditions. Here, we report the discovery of the diarylquinoline TBAJ-5307 as a broad spectrum anti-NTM inhibitor, targeting the FO domain of the engine and preventing rotation and proton translocation. TBAJ-5307 is active at low nanomolar concentrations against fast- and slow-growing NTM as well as clinical isolates by depleting intrabacterial ATP. As demonstrated for the fast grower Mycobacterium abscessus, the compound is potent in vitro and in vivo, without inducing toxicity. Combining TBAJ-5307 with anti-NTM antibiotics or the oral tebipenem-avibactam pair showed attractive potentiation. Furthermore, the TBAJ-5307-tebipenem-avibactam cocktail kills the pathogen, suggesting a novel oral combination for the treatment of NTM lung infections.

Broadening the Spectrum of SLC22A5 Phenotype: Primary Carnitine Deficiency Presenting with Focal Myoclonus.

Primary carnitine deficiency (PCD) is caused by pathogenic variants of the SLC22A5 gene, which encodes a transmembrane protein that functions as a high affinity carnitine transporter. Carnitine is essential for the transport of acyl-CoA, produced from fatty acids, into the mitochondria where they are oxidised to produce energy. We present the case history of an 8-year-old boy who presented with fever, lethargy, focal rhythmic (3 Hz) left wrist twitching, and severe encephalopathy. MRI brain showed basal ganglia involvement. Metabolic investigations revealed low serum carnitine; whole genome sequencing confirmed compound heterozygous SLC22A5 mutations. With carnitine replacement, intensive care support, and neurorehabilitation, he made a remarkable recovery, regaining independent breathing, speech, mobility, and hand use. Seizure presentation in PCD is rare and presentation with sustained focal myoclonus has not been previously reported. This case expands the known phenotype of PCD. Prompt carnitine replacement is imperative.

Neisseria species as pathobionts in bronchiectasis.

Neisseria species are frequently identified in the bronchiectasis microbiome, but they are regarded as respiratory commensals. Using a combination of human cohorts, next-generation sequencing, systems biology, and animal models, we show that bronchiectasis bacteriomes defined by the presence of Neisseria spp. associate with poor clinical outcomes, including exacerbations. Neisseria subflava cultivated from bronchiectasis patients promotes the loss of epithelial integrity and inflammation in primary epithelial cells. In vivo animal models of Neisseria subflava infection and metabolipidome analysis highlight immunoinflammatory functional gene clusters and provide evidence for pulmonary inflammation. The murine metabolipidomic data were validated with human Neisseria-dominant bronchiectasis samples and compared with disease in which Pseudomonas-, an established bronchiectasis pathogen, is dominant. Metagenomic surveillance of Neisseria across various respiratory disorders reveals broader importance, and the assessment of the home environment in bronchiectasis implies potential environmental sources of exposure. Thus, we identify Neisseria species as pathobionts in bronchiectasis, allowing for improved risk stratification in this high-risk group.

Endocrine Manifestations and New Developments in Mitochondrial Disease.

Mitochondrial diseases are a group of common inherited diseases causing disruption of oxidative phosphorylation. Some patients with mitochondrial disease have endocrine manifestations, with diabetes mellitus being predominant but also include hypogonadism, hypoadrenalism, and hypoparathyroidism. There have been major developments in mitochondrial disease over the past decade that have major implications for all patients. The collection of large cohorts of patients has better defined the phenotype of mitochondrial diseases and the majority of patients with endocrine abnormalities have involvement of several other systems. This means that patients with mitochondrial disease and endocrine manifestations need specialist follow-up because some of the other manifestations, such as stroke-like episodes and cardiomyopathy, are potentially life threatening. Also, the development and follow-up of large cohorts of patients means that there are clinical guidelines for the management of patients with mitochondrial disease. There is also considerable research activity to identify novel therapies for the treatment of mitochondrial disease. The revolution in genetics, with the introduction of next-generation sequencing, has made genetic testing more available and establishing a precise genetic diagnosis is important because it will affect the risk for involvement for different organ systems. Establishing a genetic diagnosis is also crucial because important reproductive options have been developed that will prevent the transmission of mitochondrial disease because of mitochondrial DNA variants to the next generation.

High Frequency of Allergic Bronchopulmonary Aspergillosis in Bronchiectasis-COPD Overlap.

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) is associated with frequent exacerbations and poor outcomes in chronic respiratory disease, but remains underdiagnosed. The role of fungal sensitization in bronchiectasis-COPD overlap (BCO) is unknown. RESEARCH QUESTION: What is the occurrence and clinical relevance of Aspergillus sensitization and ABPA in BCO when compared with individuals with COPD or bronchiectasis without overlap? STUDY DESIGN: Prospective, observational, cross-sectional study. METHODS: We prospectively recruited 280 patients during periods of clinical stability with bronchiectasis (n = 183), COPD (n = 50), and BCO (n = 47) from six hospitals across three countries (Singapore, Malaysia, and Scotland). We assessed sensitization responses (as specific IgE) to a panel of recombinant Aspergillus fumigatus allergens and the occurrence of ABPA in relationship to clinical outcomes. RESULTS: Individuals with BCO show an increased frequency and clinical severity of ABPA compared with those with COPD and bronchiectasis without overlap. BCO-associated ABPA is associated with more severe disease, higher exacerbation rates, and lower lung function when compared with ABPA occurring in the absence of overlap. BCO with a severe bronchiectasis severity index (BSI; > 9) is associated significantly with the occurrence of ABPA that is unrelated to underlying COPD severity. CONCLUSIONS: BCO demonstrates a high frequency of ABPA that is associated with a severe BSI (> 9) and poor clinical outcomes. Clinicians should maintain a high index of suspicion for the potential development of ABPA in patients with BCO with high BSI.

Natural History of Leigh Syndrome: A Study of Disease Burden and Progression.

OBJECTIVE: This observational cohort study aims to quantify disease burden over time, establish disease progression rates, and identify factors that may determine the disease course of Leigh syndrome. METHODS: Seventy-two Leigh syndrome children who completed the Newcastle Paediatric Mitochondrial Disease Scale (NPMDS) at baseline at 3.7 years (interquartile range [IQR] = 2.0-7.6) and follow-up assessments at 7.5 years (IQR = 3.7-11.0) in clinics were enrolled. Eighty-two percent of this cohort had a confirmed genetic diagnosis, with pathogenic variants in the MT-ATP6 and SURF1 genes being the most common cause. The total NPMDS scores denoted mild (0-14), moderate (15-25), and severe (>25) disease burden. Detailed clinical, neuroradiological, and molecular genetic findings were also analyzed. RESULTS: The median total NPMDS scores rose significantly (Z = -6.9, p < 0.001), and the percentage of children with severe disease burden doubled (22% → 42%) over 2.6 years of follow-up. Poor function (especially mobility, self-care, communication, feeding, and education) and extrapyramidal features contributed significantly to the disease burden (τb  ≈ 0.45-0.68, p < 0.001). These children also deteriorated to wheelchair dependence (31% → 57%), exclusive enteral feeding (22% → 46%), and one-to-one assistance for self-care (25% → 43%) during the study period. Twelve children (17%) died after their last NPMDS scores were recorded. These children had higher follow-up NPMDS scores (disease burden; p < 0.001) and steeper increase in NPMDS score per annum (disease progression; p < 0.001). Other predictors of poor outcomes include SURF1 gene variants (p < 0.001) and bilateral caudate changes on neuroimaging (p < 0.01). INTERPRETATION: This study has objectively defined the disease burden and progression of Leigh syndrome. Our analysis has also uncovered potential influences on the trajectory of this neurodegenerative condition. ANN NEUROL 2022;91:117-130.

Epidemiology and economic burden of bronchiectasis requiring hospitalisation in Singapore.

BACKGROUND AND OBJECTIVE: Little is known about the epidemiology and cost of bronchiectasis in Asia. This study describes the disease burden of bronchiectasis in Singapore. METHODS: A nationwide administrative dataset was used to identify hospitalisations with bronchiectasis as a diagnosis. Population statistics and medical encounter data were used to estimate the incidence, mortality, prevalence and direct medical costs associated with bronchiectasis requiring hospitalisation. RESULTS: There were 420 incident hospitalised bronchiectasis patients in 2017, giving an incidence rate of 10.6 per 100 000. Age-standardised incidence declined on average by 2.7% per year between 2007 and 2017. Incidence rates increased strongly with age in both men and women. Tuberculosis was a secondary diagnosis in 37.5% of incident hospitalisations in 2007, but has declined sharply since then. Patient survival was considerably lower in both men (5-year relative survival ratios (RSR) 0.63, 95% CI 0.59-0.66) and women (5-year RSR 0.75, 95% CI 0.72-0.78). The point prevalence of bronchiectasis was 147.1 per 100 000 in 2017, and increased sharply with age, with >1% of people aged ≥75 years having bronchiectasis. Total first-year costs among incident bronchiectasis patients in 2016 varied widely, with a mean±sd USD 7331±8863. Approximately 10% of the patients admitted in 2016 had total first-year costs of more than USD 14 380. CONCLUSION: Bronchiectasis is common and imposes a substantial burden on healthcare costs and survival rates of patients in Singapore.

Integrative microbiomics in bronchiectasis exacerbations.

Bronchiectasis, a progressive chronic airway disease, is characterized by microbial colonization and infection. We present an approach to the multi-biome that integrates bacterial, viral and fungal communities in bronchiectasis through weighted similarity network fusion ( https://integrative-microbiomics.ntu.edu.sg ). Patients at greatest risk of exacerbation have less complex microbial co-occurrence networks, reduced diversity and a higher degree of antagonistic interactions in their airway microbiome. Furthermore, longitudinal interactome dynamics reveals microbial antagonism during exacerbation, which resolves following treatment in an otherwise stable multi-biome. Assessment of the Pseudomonas interactome shows that interaction networks, rather than abundance alone, are associated with exacerbation risk, and that incorporation of microbial interaction data improves clinical prediction models. Shotgun metagenomic sequencing of an independent cohort validated the multi-biome interactions detected in targeted analysis and confirmed the association with exacerbation. Integrative microbiomics captures microbial interactions to determine exacerbation risk, which cannot be appreciated by the study of a single microbial group. Antibiotic strategies probably target the interaction networks rather than individual microbes, providing a fresh approach to the understanding of respiratory infection.

Current and Emerging Clinical Treatment in Mitochondrial Disease.

Primary mitochondrial disease (PMD) is a group of complex genetic disorders that arise due to pathogenic variants in nuclear or mitochondrial genomes. Although PMD is one of the most prevalent inborn errors of metabolism, it often exhibits marked phenotypic variation and can therefore be difficult to recognise. Current treatment for PMD revolves around supportive and preventive approaches, with few disease-specific therapies available. However, over the last decade there has been considerable progress in our understanding of both the genetics and pathophysiology of PMD. This has resulted in the development of a plethora of new pharmacological and non-pharmacological therapies at varying stages of development. Many of these therapies are currently undergoing clinical trials. This review summarises the latest emerging therapies that may become mainstream treatment in the coming years. It is distinct from other recent reviews in the field by comprehensively addressing both pharmacological non-pharmacological therapy from both a bench and a bedside perspective. We highlight the current and developing therapeutic landscape in novel pharmacological treatment, dietary supplementation, exercise training, device use, mitochondrial donation, tissue replacement gene therapy, hypoxic therapy and mitochondrial base editing.

Temporal changes of haematological and radiological findings of the COVID-19 infection-a review of literature.

BACKGROUND: COVID-19 is a systemic viral infection which mainly targets the human respiratory system with many secondary clinical manifestations especially affecting the hematopoietic system and haemostasis. Few studies have highlighted the prognostic value of blood findings such as lymphopenia, neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, LDH, CRP, cardiac troponin, low-density lipoproteins and chest radiographic abnormality. A study of progressions of blood and radiological results may help to identify patients at high risk of severe outcomes. This systematic review aimed to assess the temporal progression of blood and radiology findings of patients with COVID-19. METHODS: Comprehensive systematic literature search was conducted on Medline, Embase and Cochrane databases to identify articles published for peripheral blood investigation and radiological results of COVID-19 patients. RESULTS: A total of 27 studies were included in this review. The common laboratory features reported include lymphopenia, elevated levels of C-reactive proteins and lactate dehydrogenase. For radiological signs, ground-glass opacifications, consolidations, and crazy paving patterns were frequently reported. There is a correlation between lymphocyte count, neutrophil count and biomarkers such as C-reactive proteins and lactate dehydrogenase; at a later phase of the disease (more than 7 days since onset of symptoms), lymphopenia worsens while neutrophil count, C-reactive protein levels and lactate dehydrogenase levels increase. Frequencies of ground-glass opacifications and ground-glass opacifications with consolidations decrease at a later phase of the disease while that of consolidation and crazy paving pattern rises as the disease progresses. More extensive lung involvement was also seen more frequently in the later phases. CONCLUSION: The correlation between temporal progression and the reported blood and radiological results may be helpful to monitor and evaluate disease progression and severity.

A novel, pathogenic dinucleotide deletion in the mitochondrial MT-TY gene causing myasthenia-like features.

Mitochondrial DNA (mtDNA)-related diseases often pose a diagnostic challenge and require rigorous clinical and laboratory investigation. Pathogenic variants in the mitochondrial tRNA gene MT-TY, which encodes the tRNATyr, are a rare cause of mitochondrial disease. Here we describe a novel m.5860delTA anticodon variant in the MT-TY gene in a patient who initially presented with features akin to a childhood onset myasthenic syndrome. Using histochemical, immunohistochemical and protein studies we demonstrate that this mutation leads to severe biochemical defects of mitochondrial translation, which is reflected in the early onset and progressive phenotype. This case highlights the clinical overlap between mtDNA-related diseases and other neuromuscular disorders, and demonstrates the potential pitfalls in analysis of next generation sequencing results, given whole exome sequencing of a blood DNA sample failed to make a genetics diagnosis. Muscle biopsy remains an important requirement in the diagnosis of mitochondrial disease and in establishing the pathogenicity of novel mtDNA variants.

Restoration of HDAC2 and Nrf2 by andrographolide overcomes corticosteroid resistance in chronic obstructive pulmonary disease.

BACKGROUND AND PURPOSE: Corticosteroid resistance poses a major barrier to an effective anti-inflammatory therapy for chronic obstructive pulmonary disease (COPD). The present study aimed to investigate potential corticosteroid re-sensitization actions of andrographolide, a bioactive molecule from the herb Andrographis paniculata, in COPD models, particularly in peripheral blood mononuclear cells (PBMCs) from COPD patients. EXPERIMENTAL APPROACH: Corticosteroid sensitivity in PBMCs collected from COPD patients, or in human monocytic U937 cells exposed to cigarette smoke extract (CSE), was determined by measuring LPS-induced IL-8 production, in the presence and absence of andrographolide. The mechanisms of corticosteroid re-sensitization action of andrographolide were evaluated in a mouse cigarette smoke (CS)-induced acute lung injury model. KEY RESULTS: Impaired inhibition of IL-8 production by dexamethasone was detected in PBMCs from COPD patients and in CSE-exposed U937 cells, together with reduced levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and histone deacetylase-2 (HDAC2). In both PBMCs and CSE-exposed U937 cells, andrographolide restored dexamethasone inhibition of IL-8 production, accompanied by the up-regulation of Nrf2 and HDAC2 levels. In the U937 cells, andrographolide was able to block CSE-induced Akt and reduce the level of c-Jun. Besides, andrographolide also augmented dexamethasone actions on lowering total and neutrophil counts, cytokine levels, and oxidative damage markers in bronchoalveolar lavage fluid from CS-exposed mice. CONCLUSION AND IMPLICATIONS: We report here for the first time a novel corticosteroid re-sensitization property of andrographolide in human PBMCs and provide mechanistic evidence to support clinical evaluation of andrographolide in reversing steroid resistance in COPD.

Increased Chitotriosidase Is Associated With Aspergillus and Frequent Exacerbations in South-East Asian Patients With Bronchiectasis.

BACKGROUND: Chitinase activity is an important innate immune defence mechanism against infection that includes fungi. The 2 human chitinases: chitotriosidase (CHIT1) and acidic mammalian chitinase are associated to allergy, asthma, and COPD; however, their role in bronchiectasis and bronchiectasis-COPD overlap (BCO) is unknown. RESEARCH QUESTION: What is the association between chitinase activity, airway fungi and clinical outcomes in bronchiectasis and bronchiectasis-COPD overlap? STUDY DESIGN AND METHODS: A prospective cohort of 463 individuals were recruited across five hospital sites in three countries (Singapore, Malaysia, and Scotland) including individuals who were not diseased (n = 35) and who had severe asthma (n = 54), COPD (n = 90), bronchiectasis (n = 241) and BCO (n = 43). Systemic chitinase levels were assessed for bronchiectasis and BCO and related to clinical outcomes, airway Aspergillus status, and underlying pulmonary mycobiome profiles. RESULTS: Systemic chitinase activity is elevated significantly in bronchiectasis and BCO and exceed the activity in other airway diseases. CHIT1 activity strongly predicts bronchiectasis exacerbations and is associated with the presence of at least one Aspergillus species in the airway and frequent exacerbations (≥3 exacerbations/y). Subgroup analysis reveals an association between CHIT1 activity and the "frequent exacerbator" phenotype in South-East Asian patients whose airway mycobiome profiles indicate the presence of novel fungal taxa that include Macroventuria, Curvularia and Sarocladium. These taxa, enriched in frequently exacerbating South-East Asian patients with high CHIT1 may have potential roles in bronchiectasis exacerbations. INTERPRETATION: Systemic CHIT1 activity may represent a useful clinical tool for the identification of fungal-driven "frequent exacerbators" with bronchiectasis in South-East Asian populations.

Establishing a Satellite Transfusion Service Within an Academic Medical Center.

OBJECTIVES: Increasingly complex medical care requires specialized transfusion support close at hand. Hospital growth can necessitate expansion of blood bank services to new locations to ensure rapid delivery of blood products. We describe the opening of a new satellite transfusion service designed to serve the needs of a pediatric hospital. METHODS: Institutional transition teams and stakeholders collaborated to discuss options for providing blood at a new pediatric hospital. A staffed satellite transfusion service met the diverse needs of multiple services and was considered a compromise between a full new transfusion service and automated solutions. RESULTS: Initial challenges in establishing the laboratory included regulatory uncertainty and interactions between two hospitals' information technology services. Laboratory scientist staffing and actual use required adapting the satellite service to an emergency release-only model. CONCLUSIONS: A flexibly staffed satellite transfusion service met the most urgent needs of a pediatric hospital expansion. Review of implementation revealed potential process improvements for future expansions, including comprehensive routine and massive transfusion simulations. The challenges experienced in supplying staff and specialized blood products track with national trends. Other institutions may consider establishing a satellite transfusion service in the context of both increasingly sophisticated automated solutions and complex blood needs.

Optimizing O-negative RBC utilization using a data-driven approach.

BACKGROUND: O-negative red blood cells (ON-RBC) are a precious resource and the international blood banking community has become increasingly concerned with its inappropriate utilization. AABB recently made several recommendations to address the issue. Solutions must be multifaceted and involve donor centers, blood banks, and clinical departments. From the perspective of a hospital blood bank, it is difficult to rely solely on increased donor recruitment and ubiquitous blood typing of the entire in-patient population. We therefore focused on interventions within the blood bank to optimize inventory and policies to ensure appropriate ON-RBC utilization. STUDY DESIGN AND METHODS: Transfusion data over one year was examined for the rate of out-of-group/inappropriate ON-RBC. Furthermore, we assessed whether that rate was related to product life on the day of transfusion. We also examined our stock inventory levels and how excess inventory can contribute to inappropriate ON-RBC usage. RESULTS: The ON-RBC inventory level was decreased in order to reduce the rate of inappropriate transfusions while maintaining a safe level for optimal patient care. Compared to baseline, our intervention caused ON-RBCs to be transfused earlier in their shelf-life (9.27 vs. 11.15 days from expiration [DFE], p = 0.0012). This reduced the overall rate of inappropriate ON-RBC transfusions (67% vs. 54%, p = 0.0035), approximating 185 units of ON-RBC saved over the course of 6 months. CONCLUSIONS: A data-driven approach to optimize stock inventory levels is widely applicable; it can be adopted by numerous institutions to improve utilization and establish a benchmark for the broader blood banking community.

The mitochondrial epilepsies.

Mitochondria are vital organelles within cells that undertake many important metabolic roles, the most significant of which is to generate energy to support organ function. Dysfunction of the mitochondrion can lead to a wide range of clinical features, predominantly affecting organs with a high metabolic demand such as the brain. One of the main neurological manifestations of mitochondrial disease is metabolic epilepsies. These epileptic seizures are more frequently of posterior quadrant and occipital lobe onset, more likely to present with non-convulsive status epilepticus which may last months and be more resistant to treatment from the onset. The onset of can be of any age. Childhood onset epilepsy is a major phenotypic feature in mitochondrial disorders such as Alpers-Huttenlocher syndrome, pyruvate dehydrogenase complex deficiencies, and Leigh syndrome. Meanwhile, adults with classical mitochondrial disease syndrome such as MELAS, MERFF or POLG-related disorders could present with either focal or generalised seizures. There are no specific curative treatments for mitochondrial epilepsy. Generally, the epileptic seizures should be managed by specialist neurologist with appropriate use of anticonvulsants. As a general rule, especially in disorders associated with mutation in POLG, sodium valproate is best avoided because hepato-toxicity can be fulminant and fatal.

Long-term tolerance of a fractured self-expanding metal stent in a patient with adenoid cystic carcinoma.

Self-expanding metals stent are used for recanalization of malignant CAO. Fracture of such a stent has been described. This prompts its removal. However removal of a metal stent is difficult and can be hazardous. Due to this US FDA advisory was released against their insertion in benign diseases where long life expectancy can expose the patients to the complications of prolonged indwelling time of these stents. We describe a case of adenoid cystic carcinoma who required SEMS placement for tracheal obstruction. However, stent fracture developed soon after its insertion causing patient to cough out stent pieces multiple times. In view of the challenge associated with removal of metal stent fixed to the tracheal walls at its proximal and distal ends, the stent was left in-situ. Patient has tolerated the fractured stent for 1-year and remains on follow-up without any complication or adverse event. This illustrates the long-term tolerance and safety of a fractured stent and helps to allay anxiety associated with this complication.

Resolving complexity in mitochondrial disease: Towards precision medicine.

Mitochondrial diseases, caused by mutations in either the nuclear or mitochondrial genomes (mtDNA), are the most common form of inherited neurometabolic disorders. They are remarkably heterogeneous, both in their clinical presentation and genetic etiology, presenting challenges for diagnosis, clinical management and elucidation of molecular mechanism. The multifaceted nature of these diseases, compounded by the unique characteristics of mitochondrial genetics, cement their space in the field of complex disease. In this review we examine the m.3243A>G variant, one of the most prevalent mitochondrial DNA mutations, using it as an exemplar to demonstrate the challenges presented by these complex disorders. Disease caused by m.3243A>G is one of the most phenotypically diverse of all mitochondrial diseases; we outline known causes of this heterogeneity including mtDNA heteroplasmy, mtDNA copy number and nuclear genetic factors. We consider the impact that this has in the clinic, discussing the personalized management of common manifestations attributed to this pathogenic mtDNA variant, including hearing impairment, diabetes mellitus, myopathy, cardiac disease, stroke-like episodes and gastrointestinal disturbances. Future research into this complex disorder must account for this heterogeneity, benefitting from the use of large patient cohorts to build upon current clinical expertise. Through multi-disciplinary collaboration, the complexities of this mitochondrial disease can be addressed with the variety of diagnostic, prognostic, and treatment approaches that are moulded to best fit the needs of each individual patient.

Multi-material three dimensional printed models for simulation of bronchoscopy.

BACKGROUND: Bronchoscopy involves exploration of a three-dimensional (3D) bronchial tree environment using just two-dimensional (2D) images, visual cues and haptic feedback. Sound knowledge and understanding of tracheobronchial anatomy as well as ample training experience is mandatory for technical mastery. Although simulated modalities facilitate safe training for inexperienced operators, current commercial training models are expensive or deficient in anatomical accuracy, clinical fidelity and patient representation. The advent of Three-dimensional (3D) printing technology may resolve the current limitations with commercial simulators. The purpose of this report is to develop and test the novel multi-material three-dimensional (3D) printed airway models for bronchoscopy simulation. METHODS: Using material jetting 3D printing and polymer amalgamation, human airway models were created from anonymized human thoracic computed tomography images from three patients: one normal, a second with a tumour obstructing the right main bronchus and third with a goitre causing external tracheal compression. We validated their efficacy as airway trainers by expert bronchoscopists. Recruited study participants performed bronchoscopy on the 3D printed airway models and then completed a standardized evaluation questionnaire. RESULTS: The models are flexible, life size, anatomically accurate and patient specific. Five expert respiratory physicians participated in validation of the airway models. All the participants agreed that the models were suitable for training bronchoscopic anatomy and access. Participants suggested further refinement of colour and texture of the internal surface of the airways. Most respondents felt that the models are suitable simulators for tracheal pathology, have a learning value and recommend it to others for use in training. CONCLUSION: Using material jetting 3D printing to create patient-specific anatomical models is a promising modality of simulation training. Our results support further evaluation of the printed airway model as a bronchoscopic trainer, and suggest that pathological airways may be simulated using this technique.