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Some patients hospitalized with acute COVID-19 suffer respiratory symptoms that persist for many months. We delineated the immune-proteomic landscape in the airways and peripheral blood of healthy controls and post-COVID-19 patients 3 to 6 months after hospital discharge. Post-COVID-19 patients showed abnormal airway (but not plasma) proteomes, with an elevated concentration of proteins associated with apoptosis, tissue repair, and epithelial injury versus healthy individuals. Increased numbers of cytotoxic lymphocytes were observed in individuals with greater airway dysfunction, while increased B cell numbers and altered monocyte subsets were associated with more widespread lung abnormalities. A one-year follow-up of some post-COVID-19 patients indicated that these abnormalities resolved over time. In summary, COVID-19 causes a prolonged change to the airway immune landscape in those with persistent lung disease, with evidence of cell death and tissue repair linked to the ongoing activation of cytotoxic T cells.
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Linfócitos B/imunologia , COVID-19/imunologia , Monócitos/imunologia , Transtornos Respiratórios/imunologia , Sistema Respiratório/imunologia , SARS-CoV-2/fisiologia , Linfócitos T Citotóxicos/imunologia , Adulto , Idoso , COVID-19/complicações , Feminino , Seguimentos , Humanos , Imunidade Celular , Imunoproteínas , Masculino , Pessoa de Meia-Idade , Proteoma , Transtornos Respiratórios/etiologia , Sistema Respiratório/patologiaRESUMO
Silicosis due to artificial stone (AS) has emerged over the last decade as an increasing global issue. We report the first eight UK cases. All were men; median age was 34 years (range 27-56) and median stone dust exposure was 12.5 years (range 4-40) but in 4 cases was 4-8 years. One is deceased; two were referred for lung transplant assessment. All cases were dry cutting and polishing AS worktops with inadequate safety measures. Clinical features of silicosis can closely mimic sarcoidosis. UK cases are likely to increase, with urgent action needed to identify cases and enforce regulations.
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Silicose , Humanos , Silicose/diagnóstico , Masculino , Pessoa de Meia-Idade , Adulto , Reino Unido , Poeira , Exposição Ocupacional/efeitos adversos , Diagnóstico Diferencial , Tomografia Computadorizada por Raios XRESUMO
BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease that affects 3 million people worldwide. Senescence and small extracellular vesicles (sEVs) have been implicated in the pathogenesis of IPF, although how sEVs promote disease remains unclear. Here, we profile sEVs from bronchial epithelial cells and determine small RNA (smRNA) content. METHODS: Conditioned media was collected and sEVs were isolated from normal human bronchial epithelial cells (NHBEs) and IPF-diseased human bronchial epithelial cells (DHBEs). RESULTS: Increased sEV release from DHBEs compared to NHBEs (n = 4; p < 0.05) was detected by nanoparticle tracking analysis. NHBEs co-cultured with DHBE-derived sEVs for 72 h expressed higher levels of SA-ß-Gal and γH2AX protein, p16 and p21 RNA and increased secretion of IL6 and IL8 proteins (all n = 6-8; p < 0.05). sEVs were also co-cultured with healthy air-liquid interface (ALI) cultures and similar results were observed, with increases in p21 and p16 gene expression and IL6 and IL8 (basal and apical) secretion (n = 6; p < 0.05). Transepithelial electrical resistance (TEER) measurements, a reflection of epithelial barrier integrity, were decreased upon the addition of DHBE-derived sEVs (n = 6; p < 0.05). smRNA-sequencing identified nineteen significantly differentially expressed miRNA in DHBE-derived sEVs compared to NHBE-derived sEVs, with candidate miRNAs validated by qPCR (all n = 5; p < 0.05). Four of these miRNAs were upregulated in NHBEs co-cultured with DHBE-derived sEVs and three in healthy ALI cultures co-cultured with DHBE-derived sEVs (n = 3-4; p < 0.05). CONCLUSIONS: This data demonstrates that DHBE-derived sEVs transfer senescence to neighbouring healthy cells, promoting the disease state in IPF.
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Vesículas Extracelulares , Fibrose Pulmonar Idiopática , MicroRNAs , Humanos , Interleucina-6/metabolismo , Interleucina-8/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Fibrose Pulmonar Idiopática/metabolismo , Vesículas Extracelulares/metabolismoRESUMO
BACKGROUND: The four different local therapy strategies used for head and neck rhabdomyosarcoma (HNRMS) include proton therapy (PT), photon therapy (RT), surgery with radiotherapy (Paris-method), and surgery with brachytherapy (AMORE). Local control and survival is comparable; however, the impact of these different treatments on facial deformation is still poorly understood. This study aims to quantify facial deformation and investigates the differences in facial deformation between treatment modalities. METHODS: Across four European and North American institutions, HNRMS survivors treated between 1990 and 2017, more than 2 years post treatment, had a 3D photograph taken. Using dense surface modeling, we computed facial signatures for each survivor to show facial deformation relative to 35 age-sex-ethnicity-matched controls. Additionally, we computed individual facial asymmetry. FINDINGS: A total of 173 HNRMS survivors were included, survivors showed significantly reduced facial growth (p < .001) compared to healthy controls. Partitioned by tumor site, there was reduced facial growth in survivors with nonparameningeal primaries (p = .002), and parameningeal primaries (p ≤.001), but not for orbital primaries (p = .080) All patients were significantly more asymmetric than healthy controls, independent of treatment modality (p ≤ .001). There was significantly more facial deformation in orbital patients when comparing RT to AMORE (p = .046). In survivors with a parameningeal tumor, there was significantly less facial deformation in PT when compared to RT (p = .009) and Paris-method (p = .007). INTERPRETATION: When selecting optimal treatment, musculoskeletal facial outcomes are an expected difference between treatment options. These anticipated differences are currently based on clinicians' bias, expertise, and experience. These data supplement clinician judgment with an objective analysis highlighting the impact of patient age and tumor site between existing treatment options.
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Neoplasias de Cabeça e Pescoço , Rabdomiossarcoma Embrionário , Rabdomiossarcoma , Criança , Humanos , Lactente , Estudos Transversais , Neoplasias de Cabeça e Pescoço/radioterapia , Rabdomiossarcoma/radioterapia , Rabdomiossarcoma/patologia , Estudos de Coortes , Terapia CombinadaRESUMO
Safely achieving the goals of the Paris Climate Agreement requires a worldwide transformation to carbon-neutral societies within the next 30 y. Accelerated technological progress and policy implementations are required to deliver emissions reductions at rates sufficiently fast to avoid crossing dangerous tipping points in the Earth's climate system. Here, we discuss and evaluate the potential of social tipping interventions (STIs) that can activate contagious processes of rapidly spreading technologies, behaviors, social norms, and structural reorganization within their functional domains that we refer to as social tipping elements (STEs). STEs are subdomains of the planetary socioeconomic system where the required disruptive change may take place and lead to a sufficiently fast reduction in anthropogenic greenhouse gas emissions. The results are based on online expert elicitation, a subsequent expert workshop, and a literature review. The STIs that could trigger the tipping of STE subsystems include 1) removing fossil-fuel subsidies and incentivizing decentralized energy generation (STE1, energy production and storage systems), 2) building carbon-neutral cities (STE2, human settlements), 3) divesting from assets linked to fossil fuels (STE3, financial markets), 4) revealing the moral implications of fossil fuels (STE4, norms and value systems), 5) strengthening climate education and engagement (STE5, education system), and 6) disclosing information on greenhouse gas emissions (STE6, information feedbacks). Our research reveals important areas of focus for larger-scale empirical and modeling efforts to better understand the potentials of harnessing social tipping dynamics for climate change mitigation.
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Interstitial lung abnormalities (ILA) can be incidentally detected in patients undergoing low-dose CT screening for lung cancer. In this retrospective study, we explore the downstream impact of ILA detection on interstitial lung disease (ILD) diagnosis and treatment. Using a targeted approach in a lung cancer screening programme, the rate of de novo ILD diagnosis was 1.5%. The extent of abnormality on CT and severity of lung function impairment, but not symptoms were the most important factors in differentiating ILA from ILD. Disease modifying therapies were commenced in 39% of ILD cases, the majority being antifibrotic therapy for idiopathic pulmonary fibrosis.
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Fibrose Pulmonar Idiopática , Doenças Pulmonares Intersticiais , Neoplasias Pulmonares , Detecção Precoce de Câncer , Humanos , Pulmão , Doenças Pulmonares Intersticiais/diagnóstico por imagem , Doenças Pulmonares Intersticiais/terapia , Neoplasias Pulmonares/diagnóstico por imagem , Estudos Retrospectivos , Tomografia Computadorizada por Raios XRESUMO
Rationale: Airway macrophages (AMs) are key regulators of the lung environment and are implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF), a fatal respiratory disease with no cure. However, knowledge about the epigenetics of AMs in IPF is limited. Objectives: To assess the role of epigenetic regulation of AMs during lung fibrosis. Methods: We undertook DNA methylation (DNAm) profiling by using Illumina EPIC (850k) arrays in sorted AMs from healthy donors (n = 14) and donors with IPF (n = 30). Cell-type deconvolution was performed by using reference myeloid-cell DNA methylomes. Measurements and Main Results: Our analysis revealed that epigenetic heterogeneity was a key characteristic of IPF AMs. DNAm "clock" analysis indicated that epigenetic alterations in IPF AMs were not associated with accelerated aging. In differential DNAm analysis, we identified numerous differentially methylated positions (n = 11) and differentially methylated regions (n = 49) between healthy and IPF AMs, respectively. Differentially methylated positions and differentially methylated regions encompassed genes involved in lipid (LPCAT1 [lysophosphatidylcholine acyltransferase 1]) and glucose (PFKFB3 [6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3]) metabolism, and importantly, the DNAm status was associated with disease severity in IPF. Conclusions: Collectively, our data identify that changes in the epigenome are associated with the development and function of AMs in the IPF lung.
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Diferenciação Celular/genética , Metilação de DNA , Epigênese Genética , Epigenoma , Fibrose Pulmonar Idiopática/genética , Fenótipo , Adulto , Idoso , Idoso de 80 Anos ou mais , Líquido da Lavagem Broncoalveolar/citologia , Estudos de Casos e Controles , Feminino , Perfilação da Expressão Gênica , Marcadores Genéticos , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Rationale: Chronic hypersensitivity pneumonitis (CHP) is a condition that arises after repeated exposure and sensitization to inhaled antigens. The lung microbiome is increasingly implicated in respiratory disease, but, to date, no study has investigated the composition of microbial communities in the lower airways in CHP.Objectives: To characterize and compare the airway microbiome in subjects with CHP, subjects with idiopathic pulmonary fibrosis (IPF), and control subjects.Methods: We prospectively recruited individuals with a CHP diagnosis (n = 110), individuals with an IPF diagnosis (n = 45), and control subjects (n = 28). Subjects underwent BAL and bacterial DNA was isolated, quantified by quantitative PCR and the 16S ribosomal RNA gene was sequenced to characterize the bacterial communities in the lower airways.Measurements and Main Results: Distinct differences in the microbial profiles were evident in the lower airways of subjects with CHP and IPF. At the phylum level, the prevailing microbiota of both subjects with IPF and subjects with CHP included Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. However, in IPF, Firmicutes dominated, whereas the percentage of reads assigned to Proteobacteria in the same group was significantly lower than the percentage found in subjects with CHP. At the genus level, the Staphylococcus burden was increased in CHP, and Actinomyces and Veillonella burdens were increased in IPF. The lower airway bacterial burden in subjects with CHP was higher than that in control subjects but lower than that of those with IPF. In contrast to IPF, there was no association between bacterial burden and survival in CHP.Conclusions: The microbial profile of the lower airways in subjects with CHP is distinct from that of IPF, and, notably, the bacterial burden in individuals with CHP fails to predict survival.
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Alveolite Alérgica Extrínseca/microbiologia , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Fibrose Pulmonar Idiopática/microbiologia , Pulmão/microbiologia , Microbiota , Adulto , Idoso , Idoso de 80 Anos ou mais , Alveolite Alérgica Extrínseca/epidemiologia , Carga Bacteriana , Feminino , Humanos , Fibrose Pulmonar Idiopática/epidemiologia , Londres/epidemiologia , Masculino , Pessoa de Meia-IdadeRESUMO
Landscapes are changing, with rural areas becoming increasingly urbanized. Children and adolescents are underrepresented in the sense-of-place literature. Our study aimed to understand how adolescent residents of a rural-urban transition area perceive and value their urbanizing landscape by examining sense of place and perceptions of landscape change. A Public Participation GIS approach, accompanied by a questionnaire survey, was applied to elicit responses from a sample of 747 students aged 12-18 in Colmenar Viejo, Madrid (Spain). Respondents' sense of "self-in-place" or home range was small, around 1 km, although valued places were identified up to around 17 km away, and occasionally further afield. Most responses were associated with urban land, with clear difference between the urban core, strongly associated with emotions, and the suburbs, with activities. Functional locations (i.e. sports facilities) and places which were valued for their social meaning (i.e. shopping malls), could be differentiated. Students were perceptive about change processes in the urban area, but not about those on the peripheral semi-natural land. Younger children were less aware than older children of spaces outside of the town and carried out fewer activities there. Females carried out fewer outdoor activities than male adolescents. In contrast to the adult population, students were more strongly focused on urban areas than on their surrounding rural landscapes. Here, awareness-raising and incentives are needed, particularly those encouraging females into the use of areas beyond the urban land. Our results suggest a lack of meaningful integration between the core city and the periphery, with lessons for urban planners.
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População Rural , Urbanização , Adolescente , Adulto , Animais , Criança , Cidades , Feminino , Humanos , Masculino , Espanha , Inquéritos e Questionários , População UrbanaRESUMO
Integrative research approaches have lost prominence in the scientific literature, and related concepts of 'wicked problems' and 'post-normal science' complement but do not adequately replace them. From a detailed examination of the foundational literature, three key principles are shown to be central to integrative research: (i) the knowledge cycle; (ii) representativeness and participation; and (iii) knowledge exchange mechanisms at the science-policy interface. As an example of the importance of the integrative research framework in the context of policy-relevant science, it is argued that the shortcomings of current climate change mitigation efforts arise from inappropriately 'closing down' the science-policy interface and focusing on a few narrow options acceptable to powerful stakeholders. This can lead to what is described as an 'ascientific' ratchet effect, where the knowledge cycle just loops endlessly between technology and capital, and science as a public good is excluded. An integrative research approach can 'open up' discourse to new ideas and actors and restore the iterative links between science-policy mechanisms. A theoretical framework is proposed in which the three concepts 'wicked problems', 'post-normal science' and 'integrative research' are nested together. Integrative research is a way to address wicked problems, sitting within the critical framing of post-normal science.
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This study explores the potential correlation between income and exposure to air pollution for the city of Madrid, Spain and its neighboring municipalities. Madrid is a well-known European air pollution hotspot with a high mortality burden attributable to nitrogen dioxide (NO2) and fine particulate matter (PM2.5). Statistical analyses were carried out using electoral district level data on gross household income (GHI), and NO2 and PM2.5 concentrations in air obtained from a mesoscale air quality model for the study area. We applied linear regression, bivariate spatial correlation analysis, spatial autoregression and geographically weighted regression to explore the relationship between contaminants and income. Three different strategies were adopted to harmonize data for analysis. While some strategies suggested a link between income and air pollution, others did not, highlighting the need for multiple different approaches where uncertainty is high. Our findings offer important lessons for future spatial geographical studies of air pollution in cities worldwide. In particular we highlight the limitations of census-scale socio-economic data and the lack of non-model derived high-resolution air quality measurement data for many cities and offers lessons for policy makers on improving the integration of these types of essential public information.
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OBJECTIVES: The objective was to measure health-related quality of life (HRQoL) of children following treatment of all-cause tracheomalacia with aortopexy. METHODS: Children ≥5 years and parents of children <18 years who had undergone aortopexy completed the Paediatric Quality of Life Inventory (PedsQL4.0). Scores were compared to published norms. RESULTS: Completed questionnaires were received from 35 parents (65%) and 10 children (38%). Median age at aortopexy was 9.8 months (1 month-12.7 years) and median years of follow-up was 2.6 (4 months-6.9 years). Children who completed questionnaires had a median age of 8.4 (5.7-13.4) years. Parent and child-reported total PedsQL scores were 69.61 (SD : 19.74), and 63.15 (SD : 20.40) respectively. Half of parents and 80% of children reported scores suggesting poor HRQoL outcomes. Parent-reported total, physical and psycho-social scores were lower than those of healthy children and those with acute illness but comparable to children with chronic health conditions and cardiovascular disease. Similarly, children themselves reported comparable total scores to children with chronic illness but child-reported psycho-social scores were lower in the aortopexy group than any other group. There was no association between PedsQL scores and cause of malacia, age or time since aortopexy. The presence of complex congenital comorbidities had a significant (p < 0.05) impact on HRQoL scores. CONCLUSIONS: Following aortopexy children remain at risk of poor HRQoL, especially those with complex comorbidities. HRQoL reported by both parent and child provides important insight into the lives of children following this procedure. Further longitudinal and qualitative study are required to better understand this complex group.
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Allergic asthma generally starts during early life and is linked to substantial tissue remodeling and lung dysfunction. Although angiogenesis is a feature of the disrupted airway, the impact of allergic asthma on the pulmonary microcirculation during early life is unknown. Here, using quantitative imaging in precision-cut lung slices (PCLSs), we report that exposure of neonatal mice to house dust mite (HDM) extract disrupts endothelial cell/pericyte interactions in adventitial areas. Central to the blood vessel structure, the loss of pericyte coverage was driven by mast cell (MC) proteases, such as tryptase, that can induce pericyte retraction and loss of the critical adhesion molecule N-cadherin. Furthermore, spatial transcriptomics of pediatric asthmatic endobronchial biopsies suggests intense vascular stress and remodeling linked with increased expression of MC activation pathways in regions enriched in blood vessels. These data provide previously unappreciated insights into the pathophysiology of allergic asthma with potential long-term vascular defects.
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Asma , Mastócitos , Humanos , Criança , Animais , Camundongos , Mastócitos/patologia , Pericitos/metabolismo , Células Endoteliais/metabolismo , Asma/patologia , Pulmão/patologia , Alérgenos , Pyroglyphidae , Modelos Animais de DoençasRESUMO
This study provides the first evidence for a role of airway sCSF1R in IPF https://bit.ly/3KTBrCA.
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Aberrant expansion of KRT5+ basal cells in the distal lung accompanies progressive alveolar epithelial cell loss and tissue remodelling during fibrogenesis in idiopathic pulmonary fibrosis (IPF). The mechanisms determining activity of KRT5+ cells in IPF have not been delineated. Here, we reveal a potential mechanism by which KRT5+ cells migrate within the fibrotic lung, navigating regional differences in collagen topography. In vitro, KRT5+ cell migratory characteristics and expression of remodelling genes are modulated by extracellular matrix (ECM) composition and organisation. Mass spectrometry- based proteomics revealed compositional differences in ECM components secreted by primary human lung fibroblasts (HLF) from IPF patients compared to controls. Over-expression of ECM glycoprotein, Secreted Protein Acidic and Cysteine Rich (SPARC) in the IPF HLF matrix restricts KRT5+ cell migration in vitro. Together, our findings demonstrate how changes to the ECM in IPF directly influence KRT5+ cell behaviour and function contributing to remodelling events in the fibrotic niche.
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Fibrose Pulmonar Idiopática , Humanos , Matriz Extracelular , Células Epiteliais Alveolares , Transporte Biológico , Movimento Celular , Queratina-5RESUMO
PURPOSE: The purpose of this paper is to determine head and neck cancer patients' perspective of their follow-up regime and to suggest ways in which these perspectives can be incorporated into current practice. DESIGN/METHODOLOGY/APPROACH: This is a prospective survey-based study. A total of 263 patients consecutively attending a head and neck cancer clinic completed a survey about their experience of the follow-up process in the post-treatment period between January 2009 and October 2009. FINDINGS: The paper finds that, of the patients, 67 per cent (n = 176) felt that the clinic met the goals they hoped would be achieved during their visit; 84 per cent (n = 221) felt that their follow-up visits were too frequent. In total 60 per cent (n = 159) were booked to see both an allied health professional and the attending clinician. Of these, 84 per cent (n = 134/159) felt that issues addressed at follow-up with the clinician duplicated those addressed by the allied healthcare professionals. When asked about their opinion of a less intensive follow-up system based on patients reporting problems and requesting appointments, 73 per cent (n = 192) favoured it. When asked who they would like to contact first in such a system, most patients (n = 118, 45 per cent) stated a clinical nurse specialist. PRACTICAL IMPLICATIONS: Current follow-up regimes may be too prescriptive in their approach without taking patient perspective into consideration. Patients felt that being seen intensively for the first year, then having visits tapered off over the next two years and finally being seen according to symptoms thereafter to be appropriate and felt that this represented an overall better system. ORIGINALITY/VALUE: These data suggest the need for a more patient-focused, individualised approach to follow-up in head and neck cancer.
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Neoplasias de Cabeça e Pescoço/psicologia , Assistência de Longa Duração/organização & administração , Satisfação do Paciente/estatística & dados numéricos , Seguimentos , Neoplasias de Cabeça e Pescoço/terapia , Pesquisas sobre Atenção à Saúde , Humanos , Londres , Assistência de Longa Duração/normasRESUMO
BACKGROUND: Fibrotic interstitial lung disease (fILD) has previously been associated with the presence of autoantibody. While studies have focused on systemic autoimmunity, the role of local autoantibodies in the airways remains unknown. We therefore extensively characterised the airway and peripheral autoantibody profiles in patients with fILD, and assessed association with disease severity and outcome. METHODS: Bronchoalveolar lavage (BAL) fluid was collected from a cohort of fILD patients and total BAL antibody concentrations were quantified. An autoantigen microarray was used to measure IgG and IgA autoantibodies against 122 autoantigens in BAL from 40 idiopathic pulmonary fibrosis (IPF), 20 chronic hypersensitivity pneumonitis (CHP), 20 connective tissue disease-associated ILD (CTD-ILD) patients and 20 controls. RESULTS: A subset of patients with fILD but not healthy controls had a local autoimmune signature in their BAL that was not present systemically, regardless of disease. The proportion of patients with IPF with a local autoantibody signature was comparable to that of CTD-ILD, which has a known autoimmune pathology, identifying a potentially novel subset of patients. The presence of an airway autoimmune signature was not associated with reduced survival probability or changes in lung function in the cohort as a whole. Patients with IPF had increased BAL total IgA and IgG1 while subjects with CHP had increased BAL IgA, IgG1 and IgG4. In patients with CHP, increased BAL total IgA was associated with reduced survival probability. CONCLUSION: Airway autoantibodies that are not present systemically identify a group of patients with fILD and the mechanisms by which these autoantibodies contribute to disease requires further investigation.
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Children are less likely than adults to suffer severe symptoms when infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while influenza A H1N1 severity is comparable across ages except for the very young or elderly. Airway epithelial cells play a vital role in the early defence against viruses via their barrier and immune functions. We investigated viral replication and immune responses in SARS-CoV-2-infected bronchial epithelial cells from healthy paediatric (n = 6; 2.5-5.6 years old) and adult (n = 4; 47-63 years old) subjects and compared cellular responses following infection with SARS-CoV-2 or Influenza A H1N1. While infection with either virus triggered robust transcriptional interferon responses, including induction of type I (IFNB1) and type III (IFNL1) interferons, markedly lower levels of interferons and inflammatory proteins (IL-6, IL-8) were released following SARS-CoV-2 compared to H1N1 infection. Only H1N1 infection caused disruption of the epithelial layer. Interestingly, H1N1 infection resulted in sustained upregulation of SARS-CoV-2 entry factors FURIN and NRP1. We did not find any differences in the epithelial response to SARS-CoV-2 infection between paediatric and adult cells. Overall, SARS-CoV-2 had diminished potential to replicate, affect morphology and evoke immune responses in bronchial epithelial cells compared to H1N1.
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COVID-19 , Vírus da Influenza A Subtipo H1N1 , Influenza Humana , Pré-Escolar , Células Epiteliais , Humanos , Imunidade , Influenza Humana/metabolismo , Interferons/metabolismo , Pessoa de Meia-Idade , SARS-CoV-2 , Replicação Viral/fisiologiaRESUMO
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.
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The community of cells lining our airways plays a collaborative role in the preservation of immune homeostasis in the lung and provides protection from the pathogens and pollutants in the air we breathe. In addition to its structural attributes that provide effective mucociliary clearance of the lower airspace, the airway epithelium is an immunologically active barrier surface that senses changes in the airway environment and interacts with resident and recruited immune cells. Single-cell RNA-sequencing is illuminating the cellular heterogeneity that exists in the airway wall and has identified novel cell populations with unique molecular signatures, trajectories of differentiation and diverse functions in health and disease. In this Review, we discuss how our view of the airway epithelial landscape has evolved with the advent of transcriptomic approaches to cellular phenotyping, with a focus on epithelial interactions with the local neuronal and immune systems.