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OBJECTIVE: To determine the association between indoor air pollution and respiratory morbidities in children with bronchopulmonary dysplasia recruited from the multicenter Bronchopulmonary Dysplasia (BPD) Collaborative. STUDY DESIGN: A cross-sectional study was performed among participants less than 3 years old in the BPD Collaborative Outpatient Registry. Indoor air pollution was defined as any reported exposure to tobacco or marijuana smoke, electronic cigarette emissions, gas stoves, and/or wood stoves. Clinical data included acute care use and chronic respiratory symptoms in the past 4 weeks. RESULTS: A total of 1,011 subjects born at a mean gestational age of 26.4 ± 2.2 weeks were included. Most (66.6%) had severe BPD. Over 40% of subjects were exposed to at least one source of indoor air pollution. The odds of reporting an emergency department visit (OR 1.7 [1.18, 2.45], antibiotic use (OR 1.9 [1.12, 3.21]), or a systemic steroid course (OR 2.18 [1.24, 3.84]) were significantly higher in subjects reporting exposure to secondhand smoke (SHS) compared with those without SHS exposure. Subjects reporting exposure to air pollution (not including SHS) also had a significantly greater odds (OR 1.48 [1.08, 2.03]) of antibiotic use as well. Indoor air pollution exposure (including SHS) was not associated with chronic respiratory symptoms or rescue medication use. CONCLUSION: Exposure to indoor air pollution, especially SHS, was associated with acute respiratory morbidities, including ED visits, antibiotics for respiratory illnesses, and systemic steroid use.
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OBJECTIVE: To identify factors associated with the timing of ventilator liberation and tracheostomy decannulation among infants with severe bronchopulmonary dysplasia (sBPD) who required chronic outpatient invasive ventilation. STUDY DESIGN: Multicenter retrospective study of 154 infants with sBPD on outpatient ventilators. Factors associated with ventilator liberation and decannulation were identified using Cox regression models and multilevel survival models. RESULTS: Ventilation liberation and decannulation occurred at median ages of 27 and 49 months, respectively. Older age at transition to a portable ventilator and at discharge, higher positive end expiratory pressure, and multiple respiratory readmissions were associated with delayed ventilator liberation. Surgical management of gastroesophageal reflux was associated with later decannulation. CONCLUSIONS: Ventilator liberation timing was impacted by longer initial admissions and higher ventilator pressure support needs, whereas decannulation timing was associated with more aggressive reflux management. Variation in the timing of events was primarily due to individual-level factors, rather than center-level factors.
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Pulmón , Células Madre Mesenquimatosas , Humanos , Recién Nacido , Pulmón/patología , Recien Nacido PrematuroRESUMEN
BACKGROUND: Bronchopulmonary dysplasia (BPD), a common complication of prematurity, is associated with outpatient morbidities, including respiratory exacerbations. Daycare attendance is associated with increased rates of acute and chronic morbidities in children with BPD. We sought to determine if additional children in the household conferred similar risks for children with BPD. METHODS: The number of children in the household and clinical outcomes were obtained via validated instruments for 933 subjects recruited from 13 BPD specialty clinics in the United States. Clustered logistic regression models were used to test for associations. RESULTS: The mean gestational age of the study population was 26.5 ± 2.2 weeks and most subjects (69.1%) had severe BPD. The mean number of children in households (including the subject) was 2.1 ± 1.3 children. Each additional child in the household was associated with a 13% increased risk for hospital admission, 13% increased risk for antibiotic use for respiratory illnesses, 10% increased risk for coughing/wheezing/shortness of breath, 14% increased risk for nighttime symptoms, and 18% increased risk for rescue medication use. Additional analyses found that the increased risks were most prominent when there were three or more other children in the household. CONCLUSIONS: We observed that additional children in the household were a risk factor for adverse respiratory outcomes. We speculate that secondary person-to-person transmission of respiratory viral infections drives this finding. While this risk factor is not easily modified, measures do exist to mitigate this disease burden. Further studies are needed to define best practices for mitigating this risk associated with household viral transmission.
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Displasia Broncopulmonar , Recién Nacido , Niño , Humanos , Lactante , Displasia Broncopulmonar/epidemiología , Displasia Broncopulmonar/complicaciones , Pacientes Ambulatorios , Encuestas y Cuestionarios , Recien Nacido Prematuro , HospitalizaciónRESUMEN
Bronchopulmonary dysplasia (BPD) is a chronic lung disease in preterm birth survivors characterized by inflammation, impaired alveolarization and dysmorphic vasculature. Activated IL-17A+ lymphocytes are key drivers of inflammation in preterm infants. We have shown that in immature mice chronic airway exposure to lipopolysaccharide (LPS) induces pulmonary inflammation, increased IL-17a expression, and hypoalveolarization, a BPD-like phenotype. The source of IL-17a and contribution to lung pathology is unknown. The natural-killer group 2, member D (NKG2D) receptor mediates activation and IL-17a production in γδ T cells by binding to stress molecules. LPS induces NKG2D ligand expression, including Rae-1 and MULT1. We hypothesized that IL-17a+ γδ T cells and NKG2D signaling mediate neonatal LPS-induced lung injury. Immature C57BL/6J (wild type), Nkg2d-/- or Tcrd-/- (lacking γδ T cells) mice were inoculated with 3ug/10ul of LPS from E. coli O26:B6 or 10ul of PBS intranasally on day of life 3, 5, 7, and 10. Selected mice were treated with neutralizing antibodies against IL-17a, or NKG2D intraperitoneally. Lung immune cells were assessed by flow cytometry and gene expression was analyzed by qPCR. Alveolar growth was assessed by lung morphometry. We established that anti-IL-17a antibody treatment attenuated LPS-induced hypoalveolarization. We found that LPS induced the fraction of IL-17a+NKG2D+ γδ T cells, a major source of IL-17a in the neonatal lung. LPS also induced lung mRNA expression of NKG2D, Rae-1, MULT1, and the DNA damage regulator p53. Anti-NKG2D treatment attenuated the effect of LPS on γδ T cell IL-17a expression, immune cell infiltration and hypoalveolarization. LPS-induced hypoalveolarization was also attenuated in Nkg2d-/- and Tcrd-/- mice. In tracheal aspirates of preterm infants IL-17A and its upstream regulator IL-23 were higher in infants who later developed BPD. Also, human ligands of NKG2D, MICA and MICB were present in the aspirates and MICA correlated with median FiO2. Our novel findings demonstrate a central role for activated IL-17a+ γδ T cells and NKG2D signaling in neonatal LPS-induced lung injury. Future studies will determine the role of NKG2D ligands and effectors, other NKG2D+ cells in early-life endotoxin-induced lung injury and inflammation with a long-term goal to understand how inflammation contributes to BPD pathogenesis.
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Displasia Broncopulmonar , Interleucina-17 , Lesión Pulmonar , Subfamilia K de Receptores Similares a Lectina de Células NK , Animales , Humanos , Recién Nacido , Ratones , Endotoxinas , Escherichia coli , Recien Nacido Prematuro , Inflamación , Ligandos , Lipopolisacáridos , Ratones Endogámicos C57BL , Subfamilia K de Receptores Similares a Lectina de Células NK/genéticaRESUMEN
OBJECTIVES: To describe outpatient respiratory outcomes and center-level variability among children with severe bronchopulmonary dysplasia (BPD) who require tracheostomy and long-term mechanical ventilation. METHODS: Retrospective cohort of subjects with severe BPD, born between 2016 and 2021, who received tracheostomy and were discharged on home ventilator support from 12 tertiary care centers participating in the BPD Collaborative Outpatient Registry. Timing of key respiratory events including time to tracheostomy placement, initial hospital discharge, first outpatient clinic visit, liberation from the ventilator, and decannulation were assessed using Kaplan-Meier analysis. Differences between centers for the timing of events were assessed via log-rank tests. RESULTS: There were 155 patients who met inclusion criteria. Median age at the time of the study was 32 months. The median age of tracheostomy placement was 5 months (48 weeks' postmenstrual age). The median ages of hospital discharge and first respiratory clinic visit were 10 months and 11 months of age, respectively. During the study period, 64% of the subjects were liberated from the ventilator at a median age of 27 months and 32% were decannulated at a median age of 49 months. The median ages for all key events differed significantly by center (P ≤ .001 for all events). CONCLUSIONS: There is wide variability in the outpatient respiratory outcomes of ventilator-dependent infants and children with severe BPD. Further studies are needed to identify the factors that contribute to variability in practice among the different BPD outpatient centers, which may include inpatient practices.
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Displasia Broncopulmonar , Recién Nacido , Lactante , Humanos , Niño , Preescolar , Displasia Broncopulmonar/terapia , Estudios Retrospectivos , Respiración Artificial , Ventiladores Mecánicos , TraqueostomíaRESUMEN
INTRODUCTION: Despite bronchopulmonary dysplasia (BPD) being a common morbidity of preterm birth, there is no validated objective tool to assess outpatient respiratory symptom control for clinical and research purposes. METHODS: Data were obtained from 1049 preterm infants and children seen in outpatient BPD clinics of 13 US tertiary care centers from 2018 to 2022. A new standardized instrument was modified from an asthma control test questionnaire and administered at the time of clinic visits. External measures of acute care use were also collected. The questionnaire for BPD control was validated in the entire population and selected subgroups using standard methodology for internal reliability, construct validity, and discriminative properties. RESULTS: Based on the scores from BPD control questionnaire, the majority of caregivers (86.2%) felt their child's symptoms were under control, which did not differ by BPD severity (p = 0.30) or a history of pulmonary hypertension (p = 0.42). Across the entire population and selected subgroups, the BPD control questionnaire was internally reliable, suggestive of construct validity (albeit correlation coefficients were -0.2 to -0.4.), and discriminated control well. Control categories (controlled, partially controlled, and uncontrolled) were also predictive of sick visits, emergency department visits, and hospital readmissions. CONCLUSION: Our study provides a tool for assessing respiratory control in children with BPD for clinical care and research studies. Further work is needed to identify modifiable predictors of disease control and link scores from the BPD control questionnaire to other measures of respiratory health such as lung function testing.
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Displasia Broncopulmonar , Nacimiento Prematuro , Lactante , Niño , Femenino , Recién Nacido , Humanos , Recien Nacido Prematuro , Pacientes Ambulatorios , Reproducibilidad de los Resultados , Encuestas y CuestionariosRESUMEN
Premature infants with chronic lung disease, bronchopulmonary dysplasia (BPD), develop recurrent cough and wheezing following respiratory viral infections. The mechanisms driving the chronic respiratory symptoms are ill-defined. We have shown that hyperoxic exposure of neonatal mice (a model of BPD) increases the activated lung CD103+ dendritic cells (DCs) and these DCs are required for exaggerated proinflammatory responses to rhinovirus (RV) infection. Since CD103+ DC are essential for specific antiviral responses and their development depends on the growth factor Flt3L, we hypothesized that early-life hyperoxia stimulates Flt3L expression leading to expansion and activation of lung CD103+ DCs and this mediates inflammation. We found that hyperoxia numerically increased and induced proinflammatory transcriptional signatures in neonatal lung CD103+ DCs, as well as CD11bhi DCs. Hyperoxia also increased Flt3L expression. Anti-Flt3L antibody blocked CD103+ DC development in normoxic and hyperoxic conditions, and while it did not affect the baseline number of CD11bhi DCs, it neutralized the effect of hyperoxia on these cells. Anti-Flt3L also inhibited hyperoxia-induced proinflammatory responses to RV. In tracheal aspirates from preterm infants mechanically-ventilated for respiratory distress in the first week of life levels of FLT3L, IL-12p40, IL-12p70 and IFN-γ were higher in infants who went on to develop BPD and FLT3L levels positively correlated with proinflammatory cytokines levels. This work highlights the priming effect of early-life hyperoxia on lung DC development and function and the contribution of Flt3L in driving these effects.
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Displasia Broncopulmonar , Hiperoxia , Animales , Humanos , Recién Nacido , Ratones , Displasia Broncopulmonar/etiología , Displasia Broncopulmonar/metabolismo , Células Dendríticas , Hiperoxia/metabolismo , Recien Nacido Prematuro , PulmónRESUMEN
OBJECTIVES: To test the hypothesis that daycare attendance among children with bronchopulmonary dysplasia (BPD) is associated with increased chronic respiratory symptoms and/or greater health care use for respiratory illnesses during the first 3 years of life. STUDY DESIGN: Daycare attendance and clinical outcomes were obtained via standardized instruments for 341 subjects recruited from 9 BPD specialty clinics in the US. All subjects were former infants born preterm (<34 weeks) with BPD (71% severe) requiring outpatient follow-up between 0 and 3 years of age. Mixed logistic regression models were used to test for associations. RESULTS: Children with BPD attending daycare were more likely to have emergency department visits and systemic steroid usage. Children in daycare up to 3 years of age also were more likely to report trouble breathing, having activity limitations, and using rescue medications when compared with children not in daycare. More severe manifestations were found in children attending daycare between 6 and 12 months of chronological age. CONCLUSIONS: In this study, children born preterm with BPD who attend daycare were more likely to visit the emergency department, use systemic steroids, and have chronic respiratory symptoms compared with children not in daycare, indicating that daycare may be a potential modifiable risk factor to minimize respiratory morbidities in children with BPD during the preschool years.
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Displasia Broncopulmonar , Displasia Broncopulmonar/complicaciones , Displasia Broncopulmonar/epidemiología , Niño , Guarderías Infantiles , Preescolar , Humanos , Lactante , Recién Nacido , Recien Nacido Prematuro , Morbilidad , Esteroides/uso terapéuticoRESUMEN
INTRODUCTION: Preterm infants and young children with bronchopulmonary dysplasia (BPD) are at increased risk for acute care utilization and chronic respiratory symptoms during early life. Identifying risk factors for respiratory morbidities in the outpatient setting could decrease the burden of care. We hypothesized that public insurance coverage was associated with higher acute care usage and respiratory symptoms in preterm infants and children with BPD after initial neonatal intensive care unit (NICU) discharge. METHODS: Subjects were recruited from BPD clinics at 10 tertiary care centers in the United States between 2018 and 2021. Demographics and clinical characteristics were obtained through chart review. Surveys for clinical outcomes were administered to caregivers. RESULTS: Of the 470 subjects included in this study, 249 (53.0%) received employer-based insurance coverage and 221 (47.0%) received Medicaid as sole coverage at least once between 0 and 3 years of age. The Medicaid group was twice as likely to have sick visits (adjusted odd ratio [OR]: 2.06; p = 0.009) and emergency department visits (aOR: 2.09; p = 0.028), and three times more likely to be admitted for respiratory reasons (aOR: 3.04; p = 0.001) than those in the employer-based group. Additionally, those in the Medicaid group were more likely to have nighttime respiratory symptoms (aOR: 2.62; p = 0.004). CONCLUSIONS: Children with BPD who received Medicaid coverage were more likely to utilize acute care and have nighttime respiratory symptoms during the first 3 years of life. More comprehensive studies are needed to determine whether the use of Medicaid represents a barrier to accessing care, lower socioeconomic status, and/or a proxy for detrimental environmental exposures.
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Displasia Broncopulmonar , Displasia Broncopulmonar/complicaciones , Displasia Broncopulmonar/epidemiología , Niño , Preescolar , Humanos , Lactante , Recién Nacido , Recien Nacido Prematuro , Cobertura del Seguro , Morbilidad , Alta del Paciente , Estados Unidos/epidemiologíaRESUMEN
Prematurity and bronchopulmonary dysplasia (BPD) increase the risk of asthma later in life. Supplemental oxygen therapy is a risk factor for chronic respiratory symptoms in infants with BPD. Hyperoxia induces cell injury and release of damage-associated molecular patterns (DAMPs). Cytoskeletal filamentous actin (F-actin) is a DAMP which binds Clec9a, a C-type lectin selectively expressed on CD103+ dendritic cells (DCs). Co-stimulation of Clec9a and TLR3 induces maximal proinflammatory responses. We have shown that neonatal hyperoxia (a model of BPD) increases lung IL-12+Clec9a+CD103+ DCs, pro-inflammatory responses and airway hyperreactivity following rhinovirus (RV) infection. CD103+ DCs and Clec9a are required for these responses. Hyperoxia increases F-actin levels in bronchoalveolar lavage fluid (BALF). We hypothesized that the F-actin severing protein gelsolin attenuates neonatal hyperoxia-induced Clec9a+CD103+ DC-dependent pro-inflammatory responses to RV and preserves alveolarization. We exposed neonatal mice to hyperoxia and treated them with gelsolin intranasally. Subsequently we inoculated the mice with RV intranasally. Alternatively, we inoculated normoxic neonatal mice with BALF from hyperoxia-exposed mice (hyperoxic BALF), RV and gelsolin. We analyzed lung gene expression two days after RV infection. For in vitro studies, lung CD11c+ cells were isolated from C57BL/6J or Clec9agfp-/- mice and incubated with hyperoxic BALF and RV. Cells were analyzed by flow cytometry. In neonatal mice, gelsolin blocked hyperoxia-induced Il12p40, TNF-α and IFN-γ mRNA and protein expression in response to RV infection. Similar effects were observed when gelsolin was co-administered with hyperoxic BALF and RV. Gelsolin decreased F-actin levels in hyperoxic BALF in vitro and inhibited hyperoxia-induced D103lo DC expansion and inflammation in vivo. Gelsolin also attenuated hyperoxia-induced hypoalveolarization. Further, incubation of lung CD11c+ cells from WT and Clec9agfp-/- mice with hyperoxic BALF and RV, showed Clec9a is required for maximal hyperoxic BALF and RV induced IL-12 expression in CD103+ DCs. Finally, in tracheal aspirates from mechanically ventilated human preterm infants the F-actin to gelsolin ratio positively correlates with FiO2, and gelsolin levels decrease during the first two weeks of mechanical ventilation. Collectively, our findings demonstrate a promising role for gelsolin, administered by inhalation into the airway to treat RV-induced exacerbations of BPD and prevent chronic lung disease.
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Displasia Broncopulmonar/tratamiento farmacológico , Gelsolina/administración & dosificación , Hiperoxia/fisiopatología , Lectinas Tipo C/metabolismo , Infecciones por Picornaviridae/tratamiento farmacológico , Receptores Inmunológicos/metabolismo , Administración por Inhalación , Animales , Animales Recién Nacidos/metabolismo , Antígenos CD/metabolismo , Displasia Broncopulmonar/virología , Femenino , Humanos , Recién Nacido , Cadenas alfa de Integrinas/metabolismo , Interleucina-12/metabolismo , Lectinas Tipo C/genética , Pulmón/metabolismo , Pulmón/patología , Pulmón/virología , Masculino , Ratones , Ratones Endogámicos C57BL , Terapia por Inhalación de Oxígeno/efectos adversos , Infecciones por Picornaviridae/virología , Receptores Inmunológicos/genética , Pruebas de Función Respiratoria , Rhinovirus/aislamiento & purificaciónRESUMEN
OBJECTIVES: Sepsis-induced immunoparalysis represents a pathologic downregulation of leukocyte function shown to be associated with adverse outcomes, although its mechanisms remain poorly understood. Our goal was to compare genome-wide gene expression profiles of immunoparalyzed and nonimmunoparalyzed children with sepsis to identify genes and pathways associated with immunoparalysis. DESIGN: Prospective observational study. PATIENTS: Twenty-six children with lower respiratory tract infection meeting criteria for sepsis, severe sepsis, or septic shock admitted to the PICU. SETTING: Two tertiary care PICUs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Innate immune function was assayed ex vivo by measuring release of tumor necrosis factor-α from whole blood after incubation with lipopolysaccharide for 4 hours. Immunoparalysis was defined as a tumor necrosis factor-α production capacity less than 200 pg/mL. Ten of the 26 children were immunoparalyzed. There were 17 significant differentially expressed genes when comparing genome-wide gene expression profiles of immunoparalyzed and nonimmunoparalyzed children (false discovery rate < 0.05). Nine genes showed increased expression in immunoparalyzed children (+1.5- to +8.8-fold change). Several of these dampen the immune system. Eight showed decreased expression in immunoparalyzed children (-1.7- to -3.9-fold change), several of which are involved in early regulation and activation of immune function. Functional annotation clustering using differentially expressed genes with p value of less than 0.05 showed three clusters related to immunity with significant enrichment scores (2.2-4.5); the most significant gene ontology terms in these clusters were antigen processing and presentation and negative regulation of interleukin-6 production. Network analysis identified potential protein interactions that may be involved in the development of immunoparalysis in children. CONCLUSIONS: In this exploratory analysis, immunoparalyzed children with sepsis showed increased expression of genes that dampen the immune system and decreased expression of genes involved in regulation and activation of the immune system. Analysis also implicated other proteins as potentially having as yet unidentified roles in the development of immunoparalysis.
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Sepsis , Choque Séptico , Niño , Humanos , Proyectos Piloto , Estudios Prospectivos , Choque Séptico/genética , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Premature infants, especially those with bronchopulmonary dysplasia (BPD), develop recurrent severe respiratory viral illnesses. We have shown that hyperoxic exposure of immature mice, a model of BPD, increases lung IL-12-producing Clec9a+ CD103+ dendritic cells (DCs), pro-inflammatory responses, and airway hyperreactivity following rhinovirus (RV) infection. However, the requirement for CD103+ DCs and Clec9a, a DAMP receptor that binds necrotic cell cytoskeletal filamentous actin (F-actin), for RV-induced inflammatory responses has not been demonstrated. To test this, 2-day-old C57BL/6J, CD103+ DC-deficient Batf3-/- or Clec9agfp-/- mice were exposed to normoxia or hyperoxia for 14 days. Also, selected mice were treated with neutralizing antibody against CD103. Immediately after hyperoxia, the mice were inoculated with RV intranasally. We found that compared with wild-type mice, hyperoxia-exposed Batf3-/- mice showed reduced levels of IL-12p40, IFN-γ, and TNF-α, fewer IFN-γ-producing CD4+ T cells, and decreased airway responsiveness following RV infection. Similar effects were observed in anti-CD103-treated and Clec9agfp-/- mice. Furthermore, hyperoxia increased airway dead cell number and extracellular F-actin levels. Finally, studies in preterm infants with respiratory distress syndrome showed that tracheal aspirate CLEC9A expression positively correlated with IL12B expression, consistent with the notion that CLEC9A+ cells are responsible for IL-12 production in humans as well as mice. We conclude that CD103+ DCs and Clec9a are required for hyperoxia-induced pro-inflammatory responses to RV infection. In premature infants, Clec9a-mediated activation of CD103+ DCs may promote pro-inflammatory responses to viral infection, thereby driving respiratory morbidity.
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Antígenos CD/metabolismo , Células Dendríticas/inmunología , Hiperoxia/fisiopatología , Cadenas alfa de Integrinas/metabolismo , Lectinas Tipo C/fisiología , Pulmón/inmunología , Neumonía/inmunología , Receptores Inmunológicos/fisiología , Síndrome de Dificultad Respiratoria del Recién Nacido/inmunología , Animales , Animales Recién Nacidos , Antígenos CD/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/fisiología , Femenino , Humanos , Recién Nacido , Recien Nacido Prematuro/inmunología , Cadenas alfa de Integrinas/genética , Pulmón/metabolismo , Pulmón/patología , Pulmón/virología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Infecciones por Picornaviridae/complicaciones , Infecciones por Picornaviridae/virología , Neumonía/virología , Proteínas Represoras/fisiología , Síndrome de Dificultad Respiratoria del Recién Nacido/metabolismo , Síndrome de Dificultad Respiratoria del Recién Nacido/patología , Rhinovirus/aislamiento & purificaciónRESUMEN
The histopathology of bronchopulmonary dysplasia (BPD) includes hypoalveolarization and interstitial thickening due to abnormal myofibroblast accumulation. Chorioamnionitis and sepsis are major risk factors for BPD development. The cellular mechanisms leading to these lung structural abnormalities are poorly understood. We used an animal model with repeated lipopolysaccharide (LPS) administration into the airways of immature mice to simulate prolonged airway exposure to gram-negative bacteria, focusing on the role of C-C chemokine receptor type 2-positive (CCR2+) exudative macrophages (ExMf). Repetitive LPS exposure of immature mice induced persistent hypoalveolarization observed at 4 and 18 days after the last LPS administration. LPS upregulated the expression of lung pro-inflammatory cytokines (TNF-α, IL-17a, IL-6, IL-1ß) and chemokines (CCL2, CCL7, CXCL1, and CXCL2), while the expression of genes involved in lung alveolar and mesenchymal cell development (PDGFR-α, FGF7, FGF10, and SPRY1) was decreased. LPS induced recruitment of ExMf, including CCR2+ ExMf, as well as other myeloid cells like DCs and neutrophils. Lungs of LPS-exposed CCR2-/- mice showed preserved alveolar structure and normal patterns of α-actin and PDGFRα expression at the tips of the secondary alveolar crests. Compared to wild type mice, a significantly lower number of ExMf, including TNF-α+ ExMf were recruited to the lungs of CCR2-/- mice following repetitive LPS exposure. Further, pharmacological inhibition of TLR4 with TAK-242 also blocked the effect of LPS on alveolarization, α-SMA and PDGFRα expression. TNF-α and IL-17a induced α-smooth muscle actin expression in the distal airspaces of E16 fetal mouse lung explants. In human preterm lung mesenchymal stromal cells, TNF-α reduced mRNA and protein expression of PDGFR-α and decreased mRNA expression of WNT2, FOXF2, and SPRY1. Collectively, our findings demonstrate that in immature mice repetitive LPS exposure, through TLR4 signaling increases lung inflammation and impairs lung alveolar growth in a CCR2-dependent manner.
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Displasia Broncopulmonar/metabolismo , Inflamación/inmunología , Macrófagos/inmunología , Alveolos Pulmonares/patología , Receptores CCR2/metabolismo , Animales , Células Cultivadas , Enfermedad Crónica , Citocinas/metabolismo , Modelos Animales de Enfermedad , Humanos , Mediadores de Inflamación/metabolismo , Lipopolisacáridos/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Receptores CCR2/genética , Transducción de SeñalRESUMEN
Inhaled oxygen, although commonly administered to patients with respiratory disease, causes severe lung injury in animals and is associated with poor clinical outcomes in humans. The relationship between hyperoxia, lung and gut microbiota, and lung injury is unknown. Here, we show that hyperoxia conferred a selective relative growth advantage on oxygen-tolerant respiratory microbial species (e.g., Staphylococcus aureus) as demonstrated by an observational study of critically ill patients receiving mechanical ventilation and experiments using neonatal and adult mouse models. During exposure of mice to hyperoxia, both lung and gut bacterial communities were altered, and these communities contributed to oxygen-induced lung injury. Disruption of lung and gut microbiota preceded lung injury, and variation in microbial communities correlated with variation in lung inflammation. Germ-free mice were protected from oxygen-induced lung injury, and systemic antibiotic treatment selectively modulated the severity of oxygen-induced lung injury in conventionally housed animals. These results suggest that inhaled oxygen may alter lung and gut microbial communities and that these communities could contribute to lung injury.
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Microbioma Gastrointestinal , Hiperoxia , Lesión Pulmonar , Animales , Humanos , Pulmón , Lesión Pulmonar/inducido químicamente , Ratones , Ratones Endogámicos C57BL , OxígenoRESUMEN
Respiratory syncytial virus (RSV) infects a majority of infants and can cause severe disease leading to increased risk to develop asthma later in life. In the present studies we detected high levels of uric acid pathway components during RSV infection and examined whether they altered the pathogenesis of RSV infection. Inhibition of uric acid (UA) pathway activation during RSV infection in airway epithelial cells using XOI decreased the expression of IL-33, thymic stromal lymphopoietin (TSLP), and CCL2. In addition, treatment of RSV infected bone marrow-derived macrophages with XOI decreased production of IL-1ß. Thus, UA activation of different cell populations contributes different innate immune mediators that promote immunopathogenesis. When mice were treated with XOI or interleukin-1 receptor antagonist (IL1-ra) during RSV infection decreased pulmonary mucus was observed along with significantly reduced numbers of ILC2 and macrophages, accompanied by decreased IL-33 in bronchoalveolar lavage of the treated mice. These findings provide mechanistic insight into the development of RSV immunopathology and indicate that xanthine metabolites and UA are key immunoregulator molecules during RSV infection. Moreover, these findings suggest uric acid and IL-1ß as possible therapeutic targets to attenuate severe RSV disease.
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Citocinas/metabolismo , Inmunidad Innata , Infecciones por Virus Sincitial Respiratorio/inmunología , Infecciones por Virus Sincitial Respiratorio/metabolismo , Virus Sincitiales Respiratorios/fisiología , Células Th2/inmunología , Células Th2/metabolismo , Ácido Úrico/metabolismo , Animales , Modelos Animales de Enfermedad , Femenino , Humanos , Mediadores de Inflamación/metabolismo , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/metabolismo , Macrófagos , Redes y Vías Metabólicas , Ratones , Mucosa Respiratoria/metabolismo , Infecciones por Virus Sincitial Respiratorio/virología , Transducción de SeñalAsunto(s)
Cardiomiopatía Dilatada/cirugía , Trasplante de Corazón/efectos adversos , Herpesvirus Humano 4/inmunología , Trastornos Linfoproliferativos/etiología , Trastornos Linfoproliferativos/cirugía , Complicaciones Posoperatorias/etiología , Adolescente , Humanos , Masculino , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
Male sex is a risk factor for development of bronchopulmonary dysplasia (BPD), a common chronic lung disease following preterm birth. We previously found that tracheal aspirate mesenchymal stromal cells (MSCs) from premature infants developing BPD show reduced expression of PDGFRα, which is required for normal lung development. We hypothesized that MSCs from male infants developing BPD exhibit a pathologic gene expression profile deficient in PDGFR and its downstream effectors, thereby favoring delayed lung development. In a discovery cohort of 6 male and 7 female premature infants, we analyzed the tracheal aspirate MSCs transcriptome. A unique gene signature distinguished MSCs from male infants developing BPD from all other MSCs. Genes involved in lung development, PDGF signaling and extracellular matrix remodeling were differentially expressed. We sought to confirm these findings in a second cohort of 13 male and 12 female premature infants. mRNA expression of PDGFRA, FGF7, WNT2, SPRY1, MMP3 and FOXF2 were significantly lower in MSCs from male infants developing BPD. In female infants developing BPD, tracheal aspirate levels of proinflammatory CCL2 and profibrotic Galectin-1 were higher compared to male infants developing BPD and female not developing BPD. Our findings support a notion for sex-specific differences in the mechanisms of BPD development.