High TSLP responses in the human infant airways are associated with pre-activated airway epithelial IFN antiviral immunity

Thymic stromal lymphopoietin (TSLP) is a primarily epithelial-derived cytokine that drives type 2 allergic immune responses. Early life viral respiratory infections elicit high TSLP production, which leads to the development of type 2 inflammation and airway hyperreactivity. The goal of this study was to examine in vivo and in vitro the human airway epithelial responses leading to high TSLP production during viral respiratory infections in early infancy. A total of 129 infants (<1-24 m, median age 10 m) with severe viral respiratory infections were enrolled for in vivo (n = 113), and in vitro studies (n = 16). Infants were classified as 'high TSLP' or 'low TSLP' for values above or below the 50th percentile. High versus low TSLP groups were compared in terms of type I-III IFN responses and production of chemokines promoting antiviral (CXCL10), neutrophilic (CXCL1, CXCL5, CXCL8), and type 2 responses (CCL11, CCL17, CCL22). Human infant airway epithelial cell (AEC) cultures were used to define the transcriptomic (RNAseq) profile leading to high versus low TSLP responses in vitro in the absence (baseline) or presence (stimulated) of a viral mimic (poly I:C). Infants in the high TSLP group had greater in vivo type III IFN airway production (median type III IFN in high TSLP 183.2 pg/mL vs. 63.4 pg/mL in low TSLP group, p = 0.007) and increased in vitro type I-III IFN AEC responses after stimulation with a viral mimic (poly I:C). At baseline, our RNAseq data showed that infants in the high TSLP group had significant upregulation of IFN signature genes (e.g., IFIT2, IFI6, MX1) and pro-inflammatory chemokine genes before stimulation. Infants in the high TSLP group also showed a baseline AEC pro-inflammatory state characterized by increased production of all the chemokines assayed (e.g., CXCL10, CXCL8). High TSLP responses in the human infant airways are associated with pre-activated airway epithelial IFN antiviral immunity and increased baseline AEC production of pro-inflammatory chemokines. These findings present a new paradigm underlying the production of TSLP in the human infant airway epithelium following early life viral exposure and shed light on the long-term impact of viral respiratory illnesses during early infancy and beyond childhood.

StethAid: A Digital Auscultation Platform for Pediatrics

(1) Background: Mastery of auscultation can be challenging for many healthcare providers. Artificial intelligence (AI)-powered digital support is emerging as an aid to assist with the interpretation of auscultated sounds. A few AI-augmented digital stethoscopes exist but none are dedicated to pediatrics. Our goal was to develop a digital auscultation platform for pediatric medicine. (2) Methods: We developed StethAid-a digital platform for artificial intelligence-assisted auscultation and telehealth in pediatrics-that consists of a wireless digital stethoscope, mobile applications, customized patient-provider portals, and deep learning algorithms. To validate the StethAid platform, we characterized our stethoscope and used the platform in two clinical applications: (1) Still's murmur identification and (2) wheeze detection. The platform has been deployed in four children's medical centers to build the first and largest pediatric cardiopulmonary datasets, to our knowledge. We have trained and tested deep-learning models using these datasets. (3) Results: The frequency response of the StethAid stethoscope was comparable to those of the commercially available Eko Core, Thinklabs One, and Littman 3200 stethoscopes. The labels provided by our expert physician offline were in concordance with the labels of providers at the bedside using their acoustic stethoscopes for 79.3% of lungs cases and 98.3% of heart cases. Our deep learning algorithms achieved high sensitivity and specificity for both Still's murmur identification (sensitivity of 91.9% and specificity of 92.6%) and wheeze detection (sensitivity of 83.7% and specificity of 84.4%). (4) Conclusions: Our team has created a technically and clinically validated pediatric digital AI-enabled auscultation platform. Use of our platform could improve efficacy and efficiency of clinical care for pediatric patients, reduce parental anxiety, and result in cost savings.

Asthma as a comorbidity in COVID-19 pediatric ICU admissions in a large metropolitan children's hospital

RATIONALE

Children contribute to 5% of coronavirus disease of 2019 (COVID-19)-related hospitalizations in the United States. There is mounting evidence suggesting childhood asthma is a risk factor for severe disease. We hypothesized that asthma is associated with longer length of stay (LOS) and need for respiratory support among children admitted to pediatric intensive care unit (PICU) with COVID-19.

METHODS

We reviewed 150 charts of children and young adults with a positive severe acute respiratory syndrome coronavirus 2polymerase chain reaction test admitted to the PICU at Children's National Hospital, Washington, DC between 2020 and 2021. We recorded demographics, anthropometrics, past medical history, clinical course, laboratory findings, imaging, medication usage, respiratory support, and outcomes. Functional Status Scale (FSS), which measures an Intensive Care Unitpatient's physical function, was used to characterize children with multiple comorbidities; FSS and obesity were included as covariates in multivariate analysis. Statistical analysis was performed using SPSS v25.0.

RESULTS

Sixty-Eight patients ages 0-21 years met inclusion criteria. Median age was 14.9 years, 55.9% were female, median Body Mass Index percentile was 62, and 42.6% were African American. Compared with those without asthma, patients with asthma averaged longer LOS (20.7 vs. 10.2 days, p = 0.02), with longer PICU stay (15.9 vs. 7.6 days, p = 0.033) and prolonged maximum respiratory support (8.3 vs. 3.3 days, p = 0.016). Adjusted for obesity and poor physical function (FSS > 6), asthma remained a significant predictor of hospital LOS, PICU LOS, and days on maximum respiratory support.

CONCLUSION

Asthma can cause severe disease with prolonged need for maximum respiratory support among children with COVID-19.

Spirometric Changes After Initiation of Hydroxyurea in Children With Sickle Cell Anemia

Individuals with sickle cell disease (SCD) develop a decline in lung function over time. Hydroxyurea (HU) is the most common disease-modifying therapy used in SCD. We hypothesized that children with SCD treated with HU will have a slower decline in pulmonary function. We performed a retrospective chart review of children with HbSS and HbS-beta zero thalassemia referred to pulmonology for respiratory symptoms. We compared the spirometry results at 2 time points between children on HU (HU group) and not on HU (control group). For the HU group, these endpoints were evaluated before and after being on HU. The mean time interval between 2 spirometry studies was not significantly different between the groups (2.6±1.5 y for HU group vs. 3.0±1.8 y for the control group; P =0.33). The mean age of patients in the HU group was 9.8±3.8 years (55% male) and 10.7±4.9 years (50% male) in the control group. The spirometry data was compared within and between the groups using t test. There was a significant increase in forced vital capacity in HU group during follow-up, while children in the control group showed a decline (7.2±17.1 vs. -3.4±18.2; P <0.01). Our study suggests that HU therapy may help preserve lung function over time in children with SCD.

Effect of the coronavirus disease 2019 pandemic on morbidity among children hospitalized for an asthma exacerbation

BACKGROUND

Pediatric asthma exacerbations account for substantial morbidity, including emergency department (ED) visits and hospitalizations. Although the coronavirus disease 2019 (COVID-19) pandemic was associated with a decrease in pediatric asthma ED visits and hospitalizations, there is limited information on the clinical characteristics of children hospitalized with an asthma exacerbation during the pandemic.

OBJECTIVE

To investigate the clinical characteristics of children hospitalized with an asthma exacerbation during the pandemic as compared with those hospitalized during the same months in the year prior.

METHODS

A retrospective case-control study was conducted at the Children's National Hospital, Washington, DC, comparing demographic and clinical characteristics of all children, 2 to 18 years old, hospitalized for an asthma exacerbation between April to September 2020 (cases) and April to September 2019 (controls).

RESULTS

We identified 50 cases and 243 controls. Cases were significantly older than controls (9.8 ± 4.3 years vs 6.7 ± 3.8 years; P < .001), had significantly less eczema (16% vs 32.1%; P = .02) and food allergies (6% vs 18.5%; P = .03), and were more noncompliant with controller medications (46% vs 24.7%; P = .002) than controls. Magnesium sulfate was more frequently administered in the ED to the cases than to the controls (84% vs 63%; P = .004). Its use was associated with older age, African American race, and Hispanic ethnicity, but was independent of comorbid conditions.

CONCLUSION

Patients hospitalized for asthma during the COVID-19 pandemic were older and have less atopy than those hospitalized prepandemic. A larger proportion received magnesium sulfate in the ED, suggesting patients had with more severe asthma presentation during the pandemic.

Personal NO2 sensor demonstrates feasibility of in-home exposure measurements for pediatric asthma research and management

BACKGROUND

One of the most common pollutants in residences due to gas appliances, NO₂ has been shown to increase the risk of asthma attacks after small increases in short term exposure. However, standard environmental sampling methods taken at the regional level overlook chronic intermittent exposure due to lack of temporal and spatial granularity. Further, the EPA and WHO do not currently provide exposure recommendations to at-risk populations.

AIMS

A pilot study with pediatric asthma patients was conducted to investigate potential deployment challenges as well as benefits of home-based NO₂ sensors and, when combined with a subject's hospital records and self-reported symptoms, the richness of data available for larger-scale epidemiological studies.

METHODS

We developed a compact personal NO₂ sensor with one minute temporal resolution and sensitivity down to 15 ppb to monitor exposure levels in the home. Patient hospital records were collected along with self-reported symptom diaries, and two example hypotheses were created to further demonstrate how data of this detail may enable study of the impact of NO₂ in this sensitive population.

RESULTS

17 patients (55%) had at least 1 h each day with average NO₂ exposure >21 ppb. Frequency of acute NO₂ exposure >21 ppb was higher in the group with gas stoves (U = 27, p ≤ 0.001), and showed a positive correlation (r_s = 0.662, p = 0.037, 95% CI 0.36-0.84) with hospital admissions.

SIGNIFICANCE

Similar studies are needed to evaluate the true impact of NO₂ in the home environment on at-risk populations, and to provide further data to regulatory bodies when developing updated recommendations.

TSLP bronchoalveolar lavage levels at baseline are linked to clinical disease severity and reduced lung function in children with asthma

RATIONALE

Thymic stromal lymphopoietin (TSLP) is increasingly recognized as a key molecule in asthma pathogenesis and as a promising therapeutic target in adults. In contrast, in asthmatic children the clinical relevance of TSLP secretion in the lower airways has been remarkably understudied. We tested the hypothesis that pulmonary TSLP levels in asthmatic children correlate with clinical severity, airway inflammation and lower airway obstruction.

METHODS

Bronchoalveolar lavage (BAL) samples and relevant clinical data were collected from asthmatic children undergoing clinically indicated bronchoscopy at Children's National Hospital in Washington D.C. Protein levels of TSLP, IL-5, IL-1β, and IL-33 were quantified in BAL at baseline and correlated with individual severity and clinical features including spirometry, serum IgE and eosinophils, BAL neutrophil and eosinophil counts.

RESULTS

We enrolled a total of 35 asthmatic children (median age: 9 years). Pediatric subjects with severe asthma had greater TSLP BAL levels at baseline relative to mild or moderate asthmatic subjects (p = 0.016). Asthmatic children with the highest TSLP levels (>75th percentile) had higher IL-5 and IL-1β BAL levels and greater lower airway obstruction (lower FEV1/FVC ratios).

CONCLUSION

Our study demonstrates for the first time that higher pulmonary TSLP levels obtained at baseline are linked to asthma disease severity in a subset of children. These data indicate that TSLP may play a key role in the pathogenesis of pediatric asthma and thus provide initial support to investigate the potential use of anti-TSLP biologics to treat severe uncontrolled asthmatic children.

Positive bronchoalveolar lavage pepsin assay associated with viral and fungal respiratory infections in children with chronic cough

OBJECTIVE

To assess the association between commonly obtained endoscopic and serologic data and bronchoalveolar lavage pepsin assay (BAL) results in children with chronic cough.

STUDY DESIGN

We performed a retrospective chart review of 72 children with a BAL pepsin obtained through our Aerodigestive Center over an 18-month period. BAL outcomes include evidence of viral, bacterial, or fungal infection, presence of lipid-laden macrophages, and cytology (eosinophils, neutrophils, and lymphocytes). Gastrointestinal outcomes include esophagogastroduodenoscopy (EGD) and pH impedance probe findings. Other characteristics include serum eosinophils, neutrophils, and lymphocytes; spirometry; FeNO; and IgE.

RESULTS

Seventy-two patients underwent BAL pepsin testing. Median age was 4.9 years, 30.6% had severe persistent asthma, and 59.2% were on reflux medication. There was an association between positive BAL pepsin assay and positive viral panel (p = .002) or fungal culture (p = .027). No significant association found between positive BAL bacterial culture; BAL cytology; the presence of BAL lipid-laden macrophages; IgE; spirometry; FeNO; CBC neutrophil, eosinophil, or lymphocytes; pH impedance testing parameters; or EGD pathology.

CONCLUSIONS

BAL pepsin is associated with a positive BAL viral PCR or fungal culture. Lack of correlation between pepsin-positivity and pH-impedance parameters or EGD pathology suggests microaspiration may be due to an acute event (such as a respiratory infection) rather than chronic gastroesophageal reflux disease. This may be especially true in the presence of a positive viral panel or fungal culture when a BAL pepsin is obtained.

Paediatric obesity-related asthma: Disease burden and effects on pulmonary physiology

The prevalence of asthma and obesity in children has been steadily increasing globally over the past several decades, with increased concern in low and middle income countries. In this review, we summarize the current literature on these two parallel epidemics and explore the relationship between paediatric obesity and asthma in the paediatric population. Finally, we focus on the current literature as it relates to underlying physiologic alterations and changes in pulmonary function for children with obesity and asthma.

A Cloud-connected NO2 and Ozone Sensor System for Personalized Pediatric Asthma Research and Management

This paper presents a cloud-connected indoor air quality sensor system that can be deployed to patients' homes to study personal microenvironmental exposure for asthma research and management. The system consists of multiple compact sensor units that can measure residential NO₂, ozone, humidity, and temperature at one-minute resolution and a cloud-based informatic system that acquires, stores, and visualizes the microenvironmental data in real-time. The sensor hardware can measure NO₂ as low as 10 ppb and ozone at 15 ppb. The cloud informatic system is implemented using open-source software on Amazon Web Service for easy deployment and scalability. This system was successfully deployed to pediatric asthma patients' homes in a pilot study. In this study, we discovered that some families had short-term NO₂ exposure higher than EPA's one-hour exposure limit (100 ppb), and NO₂ micro-pollution episodes often arise from natural gas appliance usage such as gas stove burning during cooking. By combining the personalized air pollutant exposure measurements with the physiological responses from monitoring devices, patient diaries, or medical records, this system can potentially enable novel asthma research and personalized asthma management.

Pediatric sleep questionnaire predicts more severe sleep apnea in children with uncontrolled asthma

OBJECTIVE

While up to 35% of children with asthma have evidence of sleep disordered breathing (SDB), it is unclear if nocturnal symptoms stem from asthma itself or SDB. The Pediatric Sleep Questionnaire (PSQ) is a validated tool for identifying SDB in childhood asthma. We hypothesize children with asthma and abnormal PSQ demonstrate decreased asthma control and are at higher risk of obstructive sleep apnea (OSA).

METHODS

We performed a retrospective, chart review of children and young adults referred to our tertiary children's hospital severe asthma clinic. Data collection included age, gender, BMI percentile, spirometry, PSQ, asthma control questionnaires, asthma severity, control, and impairment. These data were evaluated in the context of polysomnography, when available.

RESULTS

205 inner-city children were included; 37.2% female, median age 6.4 y, and mean BMI of 71.3%ile. Rhinitis (p = 0.028), eczema (p = 0.002), and reflux (p = 0.046) were associated with abnormal PSQ; however, overweight/obese status, spirometry, asthma severity, and serologic markers were not. After correcting for comorbidities, abnormal PSQ score was associated with poor asthma control based on validated measures (p < 0.001). In patients with polysomnography, we confirmed abnormal PSQ was associated with increased OSA severity (apnea-hypopnea index 9.1/hr vs. 3.6/hr; p = 0.027).

CONCLUSIONS

In pediatric asthma, positive PSQ was associated with significantly decreased asthma control. Additionally, children with normal PSQ demonstrated mild OSA, while children with abnormal PSQ had increased severity of OSA. This demonstrates that PSQ can be used to screen children for more severe sleep apnea.

Innate IFN-lambda responses to dsRNA in the human infant airway epithelium and clinical regulatory factors during viral respiratory infections in early life

INTRODUCTION

IFN lambda (type III-IFN-λ1) is a molecule primarily produced by epithelial cells that provides an important first-line defence against viral respiratory infections and has been linked to the pathogenesis of viral-induced wheezing in early life. The goal of this study was to better understand the regulation of innate IFN-lambda responses in vitro in primary human infant airway epithelial cells (AECs) and in vivo using nasal aspirates during viral respiratory infections.

METHODS

IFN-lambda protein levels were quantified: (a) in human infant AECs exposed to (poly(I:C) dsRNA) under different experimental conditions (n = 8 donors); and (b) in nasal aspirates of young children (≤3 years) hospitalized with viral respiratory infection (n = 138) and in uninfected controls (n = 74). In vivo IFN-lambda airway levels during viral infections were correlated with individual characteristics and respiratory disease parameters.

RESULTS

Our in vitro experiments showed that the poly(I:C)-induced innate production of IFN lambda in human infant AECs is regulated by (a) p38-MAPK/NF-kB dependent mechanism; and (b) exposure to pro-inflammatory signals such as IL1β. Our in vivo studies demonstrated that (a) infants (<18 months) had higher virus-induced IFN-lambda airway secretion; (b) subjects with RSV infection showed the highest IFN-lambda airway levels; and (c) individuals with the highest virus-induced IFN-lambda levels (>90th percentile) had higher viral loads and were more likely to have respiratory sick visits within 12 months of discharge (OR = 5.8).

CONCLUSION

IFN-lambda responses to dsRNA in the human infant airway epithelium are regulated by p38-MAPK and NF-kB signalling. High in vivo IFN-lambda production is influenced by virus type and associated with recurrent respiratory sick visits in young children.

High BAL sRAGE is Associated with Low Serum Eosinophils and IgE in Children with Asthma

Asthma remains the most common chronic lung disease in childhood in the United States. The receptor for advanced glycation end products (RAGE) has been recognized as both a marker of and participant in pulmonary pathophysiology. While membrane-bound RAGE (mRAGE) perpetuates the type 2 immune response, the soluble form (sRAGE) may act as a decoy receptor for pro-inflammatory ligands. Bronchoalveolar samples from 45 pediatric patients with asthma were obtained. Patients were divided into high and low BAL sRAGE groups using median sRAGE. Descriptive statistical analysis and non-parametric testing were applied. Children in the "high" sRAGE group had a lower median serum eosinophil (0.27 [SE ± 0.04] vs. 0.57 [± 0.06] K/mcl, adjusted p = 0.003) and lower serum IgE level (194.4 [± 60.7] vs. 676.2 ± 140.5) IU/mL, adjusted p = 0.004) as compared to the "low" sRAGE group. When controlling for age and body mass index percentile, absolute eosinophil count (p = 0.03) and serum IgE (p = 0.043) remained significantly lower in the "high" sRAGE group. Children with asthma and high levels of BAL sRAGE have lower serum eosinophil and IgE levels. These findings are consistent with the hypothesis that sRAGE may act as a decoy receptor by binding ligands that normally interact with mRAGE.

Pediatric Quality-of-Life Scores Following a Multidisciplinary Aerodigestive Team Approach to Manage Chronic Cough

OBJECTIVES

Chronic recalcitrant cough is present in 2/3 of pediatric patients evaluated in our tertiary-care multidisciplinary aerodigestive clinic (ADC). This study aimed to determine the impact of chronic cough and efficacy of ADC treatment using the validated Pediatric-Cough Quality-of-Life-27 tool (PC-QOL-27).

METHODS

The PC-QOL-27 survey was administered to ADC patients with chronic cough at initial clinic visit and 6 to 12 weeks after cough management. Pre and post survey scores, demographic data, treatment and evaluation season were collected over 16 months.

RESULTS

Twenty parents completed pre and post PC-QOL-27 surveys (mean 12.1 weeks later). Patient median age was 6.04 years (IQR: 2.2-10.44 years). A total of 65% were males and 65% were African American. Management was tailored based on clinical assessment and diagnostic studies, including direct laryngoscopy/bronchoscopy (4), pulmonary function tests (PFT's 9), esophagogastroduodenoscopy (9), and flexible bronchoscopy/lavage (9).Following ADC management, changes in physical, social and psychological domain scores of the PC-QOL-27 each met the threshold for minimal clinical important difference (MCID) indicating a clinically meaningful improvement. Improvements were most notable in the physical domain where post survey scores significantly improved from pre-survey scores (P = .009) regardless of age, gender, ethnicity, history of endoscopy and season.

CONCLUSIONS

The physical impact of chronic cough in pediatric patients who failed prior management by a single specialist was lessened by an ADC team approach to management.

Aerodigestive Approach to Chronic Cough in Children

Purpose of review

Chronic cough is the most common presenting complaint in a pediatric aerodigestive clinic. The etiology of chronic cough is varied and often includes more than one organ system. This review aims to summarize the current literature for a multidisciplinary approach when evaluating a child with chronic cough.

Recent findings

There is very little medical literature focused on a multidisciplinary approach to chronic cough. In the limited data available, multidisciplinary clinics have been shown to be more cost-efficient for the families of children with complex medical problems, and also increase the likelihood of successfully obtaining a diagnosis.

Summary

There is no consensus in the literature on how to work-up a child with chronic cough presenting to an aerodigestive clinic. Current studies from these clinics have shown improved outcomes related to cost-effectiveness and identifying definitive diagnoses. Future studies evaluating clinical outcomes are necessary to help delineate the utility of testing routinely performed, and to demonstrate the impact of interventions from each specialty on quality of life and specific functional outcome measures.

A Heterotopic Xenograft Model of Human Airways for Investigating Fibrosis in Asthma

Limited in vivo models exist to investigate the lung airway epithelial role in repair, regeneration, and pathology of chronic lung diseases. Herein, we introduce a novel animal model in asthma-a xenograft system integrating a differentiating human asthmatic airway epithelium with an actively remodeling rodent mesenchyme in an immunocompromised murine host. Human asthmatic and nonasthmatic airway epithelial cells were seeded into decellularized rat tracheas. Tracheas were ligated to a sterile cassette and implanted subcutaneously in the flanks of nude mice. Grafts were harvested at 2, 4, or 6 weeks for tissue histology, fibrillar collagen, and transforming growth factor-β activation analysis. We compared immunostaining in these xenografts to human lungs. Grafted epithelial cells generated a differentiated epithelium containing basal, ciliated, and mucus-expressing cells. By 4 weeks postengraftment, asthmatic epithelia showed decreased numbers of ciliated cells and decreased E-cadherin expression compared with nonasthmatic grafts, similar to human lungs. Grafts seeded with asthmatic epithelial cells had three times more fibrillar collagen and induction of transforming growth factor-β isoforms at 6 weeks postengraftment compared with nonasthmatic grafts. Asthmatic epithelium alone is sufficient to drive aberrant mesenchymal remodeling with fibrillar collagen deposition in asthmatic xenografts. Moreover, this xenograft system represents an advance over current asthma models in that it permits direct assessment of the epithelial-mesenchymal trophic unit.

Is a Multidisciplinary Aerodigestive Clinic More Effective at Treating Recalcitrant Aerodigestive Complaints Than a Single Specialist?

Objective:

To determine the utility of a pediatric multidisciplinary aerodigestive clinic (ADC) in treating recalcitrant aerodigestive conditions.

Methods:

Longitudinal observational study of presenting complaints, evaluation, management, and outcome of patients seen during 12 monthly ADCs beginning August 2013.

Results:

Fifty-five patients were seen by the ADC team (otolaryngology/gastroenterology/pulmonology/speech pathology/nurse practitioner) and followed for a mean 17.6 months (range, 12-26 months). Mean age was 4.3 years (range, 0.5-19 years). All were seen by at least 1 specialist before ADC referral but without significant improvement. Chronic cough was the most common primary symptom (44%). Clinic evaluation included flexible nasopharyngolaryngoscopy (FFL, 53%) and pulmonary function testing (36%.) FFL influenced management in 79%. An operative procedure usually combined endoscopy was warranted in 58%. Endoscopy provided high diagnostic yield, detecting laryngeal cleft (8), adenoid hypertrophy (8), vocal cord dysfunction (4), pulmonary infection (4), reflux disease (3), laryngomalacia (3), tracheomalacia (2), cilia abnormality (2), celiac disease (1), Helicobacter pylori (1), duodenal web (1), and eosinophilic esophagitis (1). Outcome was available for 48 of 55 patients, with 73% reporting resolved to markedly improved symptoms and 27% minimal to no improvement.

Conclusions:

The ADC team approach resulted in resolved to markedly improved symptoms in 73% of patients whose symptoms persisted despite seeing a single specialist prior to referral.

Airway Secretory microRNAome Changes during Rhinovirus Infection in Early Childhood

BACKGROUND

Innate immune responses are fine-tuned by small noncoding RNA molecules termed microRNAs (miRs) that modify gene expression in response to the environment. During acute infections, miRs can be secreted in extracellular vesicles (EV) to facilitate cell-to-cell genetic communication. The purpose of this study was to characterize the baseline population of miRs secreted in EVs in the airways of young children (airway secretory microRNAome) and examine the changes during rhinovirus (RV) infection, the most common cause of asthma exacerbations and the most important early risk factor for the development of asthma beyond childhood.

METHODS

Nasal airway secretions were obtained from children (≤3 yrs. old) during PCR-confirmed RV infections (n = 10) and age-matched controls (n = 10). Nasal EVs were isolated with polymer-based precipitation and global miR profiles generated using NanoString microarrays. We validated our in vivo airway secretory miR data in an in vitro airway epithelium model using apical secretions from primary human bronchial epithelial cells (HBEC) differentiated at air-liquid interface (ALI). Bioinformatics tools were used to determine the unified (nasal and bronchial) signature airway secretory miRNAome and changes during RV infection in children.

RESULTS

Multiscale analysis identified four signature miRs comprising the baseline airway secretory miRNAome: hsa-miR-630, hsa-miR-302d-3p, hsa- miR-320e, hsa-miR-612. We identified hsa-miR-155 as the main change in the baseline miRNAome during RV infection in young children. We investigated the potential biological relevance of the airway secretion of hsa-mir-155 using in silico models derived from gene datasets of experimental in vivo human RV infection. These analyses confirmed that hsa-miR-155 targetome is an overrepresented pathway in the upper airways of individuals infected with RV.

CONCLUSIONS

Comparative analysis of the airway secretory microRNAome in children indicates that RV infection is associated with airway secretion of EVs containing miR-155, which is predicted in silico to regulate antiviral immunity. Further characterization of the airway secretory microRNAome during health and disease may lead to completely new strategies to treat and monitor respiratory conditions in all ages.

Sex differences in the association between neck circumference and asthma

INTRODUCTION

The association between obesity and asthma control/quality of life commonly relies on body mass index (BMI) as the anthropomorphic measure. Due to limitations of BMI and the existence of alternative measures, such as neck circumference (NC), we examined the association between NC and asthma control/quality of life, with particular attention to male-female differences.

MATERIALS AND METHODS

The AsthMaP-2 Project is an observational study of youth with physician-diagnosed asthma. NC was stratified according to age- and sex-specific cutoffs and associated with asthma control (via Asthma Control Test [ACT]) and quality of life (via Integrated Therapeutics Group [ITG]-Asthma Short Form).

RESULTS

The mean ± SD age was 11.9 ± 3.6 years, and 53% were male (N = 116). The mean BMI percentile was at the 71 ± 28 percentile. Thirty-one participants (27%) met criteria for high NC. Males with high NC had significantly worse asthma control (P = 0.02) and lower quality of life than those with low NC. No similar association was found for females and the proportion of variability in ACT and ITG was best explained by BMI percentile. Conversely, for males, the proportion of variability in these scores explained by NC was larger than BMI percentile alone (Cohen's f(2)  = 0.04-0.09, a small to medium effect size).

DISCUSSION

Among male youth with asthma, combined use of NC and BMI percentile explained asthma control and quality of life better than BMI alone. Future studies of asthma should include measurement of NC and other anthropogenic measures of regional adiposity to clarify sex differences in asthma. Pediatr Pulmonol. 2016; 51:893-900. © 2016 Wiley Periodicals, Inc.

Impact of Obesity on Clinical Outcomes in Urban Children Hospitalized for Status Asthmaticus

BACKGROUND AND OBJECTIVE

The prevalence of both childhood asthma and obesity remain at historically high levels and disproportionately affect urban children. Asthma is a common and costly cause for pediatric hospitalization. Our objective was to determine the effect of obesity on outcomes among urban children hospitalized with status asthmaticus.

METHODS

A retrospective cohort study was performed by using billing system data and chart review to evaluate urban children admitted for asthma. Demographics, asthma severity, reported comorbidities, and outcomes were assessed. Obesity was defined by BMI percentile (lean<85%, overweight 85%-95%, obese≥95%). Outcomes were length of stay, hospitalization charges, ICU stay, repeat admissions, and subsequent emergency department (ED) visits. Bivariate analysis assessed for differences between overweight/obese and lean children. Multivariable regression assessed the relationship between overweight status and primary outcomes while controlling for other variables. Post hoc age-stratified analysis was also performed.

RESULTS

The study included 333 subjects; 38% were overweight/obese. Overweight/obese children admitted with asthma were more likely than lean children to have subsequent ED visits (odds ratio 1.6, 95% confidence interval 1.0-2.6). When stratified by age, overweight/obese preschool-age children (<5 years) were >2 times as likely to have repeat ED visits than lean preschool-age children (odds ratio 2.3, 95% confidence interval 1.0-5.6). There were no differences in the other outcomes between overweight/obese and lean individuals within the entire cohort or within other age groups.

Comparison of Mannheimia haemolytica isolates from an outbreak of bovine respiratory disease

The objective of this study was to determine the clonal relatedness of Mannheimia haemolytica isolates responsible for an outbreak of bovine respiratory disease in a commercial feedlot. The isolates were obtained from the lungs of 21 calves with fatal pneumonia that were part of a group of 206 total calves. All isolates were serotyped and analyzed by pulsed-field gel electrophoresis (PFGE) and for antibiotic sensitivity patterns. ELISA and immunoblotting assays were performed to compare serum antibody levels to M. haemolytica antigens in calves with fatal pneumonia to those calves that survived the outbreak. Isolates were categorized into 14 different PFGE groups based on 90% similarity. Two Group D isolates (1 and 6), and 3 Group H isolates (14, 15, and 16) were characterized as 100% similar. Antimicrobial susceptibility profiles defined 8 groups based on differences in patterns of resistance between isolates. The two 100% similar isolates from PFGE Group D were both in susceptibility Group 1. All but isolate 14 from PFGE Group H (3, 15, 16, and 19) were in susceptibility Group 4a. Serum antibody levels to M. haemolytica antigens in the dead calves were not different than the antibody levels in the 185 calves that survived the outbreak. Immunoblots of selected isolates from each of the PFGE groups demonstrated only minimal differences in antigenic profiles between strains when reacted with serum from calves that either died from or survived the outbreak. Based on the characteristics of these isolates, multiple strains of M. haemolytica were responsible for fatal pneumonia during this outbreak.

Quantitative proteomics reveals an altered cystic fibrosis in vitro bronchial epithelial secretome

Alterations in epithelial secretions and mucociliary clearance contribute to chronic bacterial infection in cystic fibrosis (CF) lung disease, but whether CF lungs are unchanged in the absence of infection remains controversial. A proteomic comparison of airway secretions from subjects with CF and control subjects shows alterations in key biological processes, including immune response and proteolytic activity, but it is unclear if these are due to mutant CF transmembrane conductance regulator (CFTR) and/or chronic infection. We hypothesized that the CF lung apical secretome is altered under constitutive conditions in the absence of inflammatory cells and pathogens. To test this, we performed quantitative proteomics of in vitro apical secretions from air-liquid interface cultures of three life-extended CF (ΔF508/ΔF508) and three non-CF human bronchial epithelial cells after labeling of CF cells by stable isotope labeling with amino acids in cell culture. Mass spectrometry analysis identified and quantitated 666 proteins across samples, of which 70 exhibited differential enrichment or depletion in CF secretions (±1.5-fold change; P < 0.05). The key molecular functions were innate immunity (24%), cytoskeleton/extracellular matrix organization (24%), and protease/antiprotease activity (17%). Oxidative proteins and classical complement pathway proteins that are altered in CF secretions in vivo were not altered in vitro. Specific differentially increased proteins-MUC5AC and MUC5B mucins, fibronectin, and matrix metalloproteinase-9-were validated by antibody-based assays. Overall, the in vitro CF secretome data are indicative of a constitutive airway epithelium with altered innate immunity, suggesting that downstream consequences of mutant CFTR set the stage for chronic inflammation and infection in CF airways.

Directional secretory response of double stranded RNA-induced thymic stromal lymphopoetin (TSLP) and CCL11/eotaxin-1 in human asthmatic airways

BACKGROUND

Thymic stromal lymphoproetin (TSLP) is a cytokine secreted by the airway epithelium in response to respiratory viruses and it is known to promote allergic Th2 responses in asthma. This study investigated whether virally-induced secretion of TSLP is directional in nature (apical vs. basolateral) and/or if there are TSLP-mediated effects occurring at both sides of the bronchial epithelial barrier in the asthmatic state.

METHODS

Primary human bronchial epithelial cells (HBEC) from control (n = 3) and asthmatic (n = 3) donors were differentiated into polarized respiratory tract epithelium under air-liquid interface (ALI) conditions and treated apically with dsRNA (viral surrogate) or TSLP. Sub-epithelial effects of TSLP were examined in human airway smooth muscle cells (HASMC) from normal (n = 3) and asthmatic (n = 3) donors. Clinical experiments examined nasal airway secretions obtained from asthmatic children during naturally occurring rhinovirus-induced exacerbations (n = 20) vs. non-asthmatic uninfected controls (n = 20). Protein levels of TSLP, CCL11/eotaxin-1, CCL17/TARC, CCL22/MDC, TNF-α and CXCL8 were determined with a multiplex magnetic bead assay.

RESULTS

Our data demonstrate that: 1) Asthmatic HBEC exhibit an exaggerated apical, but not basal, secretion of TSLP after dsRNA exposure; 2) TSLP exposure induces unidirectional (apical) secretion of CCL11/eotaxin-1 in asthmatic HBEC and enhanced CCL11/eotaxin-1 secretion in asthmatic HASMC; 3) Rhinovirus-induced asthma exacerbations in children are associated with in vivo airway secretion of TSLP and CCL11/eotaxin-1.

CONCLUSIONS

There are virally-induced TSLP-driven secretory immune responses at both sides of the bronchial epithelial barrier characterized by enhanced CCL11/eotaxin-1 secretion in asthmatic airways. These results suggest a new model of TSLP-mediated eosinophilic responses in the asthmatic airway during viral-induced exacerbations.

Directional secretomes reflect polarity-specific functions in an in vitro model of human bronchial epithelium

The polarity of the conducting airway epithelium is responsible for its directional secretion. This is an essential characteristic of lung integrity and function that dictates interactions between the external environment (apical) and subepithelial structures (basolateral). Defining the directional secretomes in the in vitro human bronchial epithelial (HBE) differentiated model could bring valuable insights into lung biology and pulmonary diseases. Normal primary HBE cells (n = 3) were differentiated into respiratory tract epithelium. Apical and basolateral secretions (24 h) were processed for proteome profiling and pathway analysis. A total of 243 proteins were identified in secretions from all HBE cultures combined. Of these, 51% were classified as secreted proteins, including true secreted proteins (36%) and exosomal proteins (15%). Close examination revealed consistent secretion of 69 apical proteins and 13 basolateral proteins and differential secretion of 25 proteins across all donors. Expression of Annexin A4 in apical secretions and Desmoglein-2 in basolateral secretions was validated using Western blot or ELISA in triplicate independent experiments. To the best of our knowledge, this is the first study defining apical and basolateral secretomes in the in vitro differentiated HBE model. The data demonstrate that epithelial polarity directs protein secretion with different patterns of biological processes to the apical and basolateral surfaces that are consistent with normal bronchial epithelium homeostatic functions. Applying this in vitro directional secretome model to lung diseases may elucidate their molecular pathophysiology and help define potential therapeutic targets.

The human secretome atlas initiative: implications in health and disease conditions

Proteomic analysis of human body fluids is highly challenging, therefore many researchers are redirecting efforts toward secretome profiling. The goal is to define potential biomarkers and therapeutic targets in the secretome that can be traced back in accessible human body fluids. However, currently there is a lack of secretome profiles of normal human primary cells making it difficult to assess the biological meaning of current findings. In this study we sought to establish secretome profiles of human primary cells obtained from healthy donors with the goal of building a human secretome atlas. Such an atlas can be used as a reference for discovery of potential disease associated biomarkers and eventually novel therapeutic targets. As a preliminary study, secretome profiles were established for six different types of human primary cell cultures and checked for overlaps with the three major human body fluids including plasma, cerebrospinal fluid and urine. About 67% of the 1054 identified proteins in the secretome of these primary cells occurred in at least one body fluid. Furthermore, comparison of the secretome profiles of two human glioblastoma cell lines to this new human secretome atlas enabled unambiguous identification of potential brain tumor biomarkers. These biomarkers can be easily monitored in different body fluids using stable isotope labeled standard proteins. The long term goal of this study is to establish a comprehensive online human secretome atlas for future use as a reference for any disease related secretome study. This article is part of a Special Issue entitled: An Updated Secretome.

Associations between genetic variants in vitamin D metabolism and asthma characteristics in young African Americans: a pilot study

INTRODUCTION

Low vitamin D levels have been associated with asthma severity in children. Young, urban African Americans (AAs) have high rates of hypovitaminosis D and asthma. Our objective was to determine associations between variants in vitamin D metabolism genes and asthma characteristics in a pilot study of young urban AAs.

MATERIALS AND METHODS

Two urban AA cohorts of subjects aged 6 to 20 years (139 subjects with asthma and 74 subjects without asthma) were genotyped for 12 single nucleotide polymorphisms (SNPs) in 3 vitamin D metabolism genes: VDR (vitamin D receptor), CYP24A1 (cytochrome P450 vitamin D 24-hydroxylase), and CYP2R1 (cytochrome P450 vitamin D 25-hydroxylase). In a case-control analysis, SNPs were studied for associations with an asthma diagnosis. Within the asthmatic cohort, SNPs were analyzed for associations with quantitative asthma characteristics. All analyses were adjusted for age, sex, and body mass index percentile.

RESULTS

Only the CYP2R1 SNP rs10766197 homozygous minor genotype was associated with asthma (P = 0.044). CYP24A1 SNP rs2248137 was associated with lower vitamin D levels (P = 0.006). Within the asthma cohort, multiple significant associations between SNPs and asthma characteristics were identified; VDR SNP rs2228570 was associated with the higher nighttime asthma morbidity scores (P = 0.04), lower baseline spirometric measures (P < 0.05), 1 or more positive aeroallergen skin test (P = 0.003), and increased immunoglobulin E levels (P < 0.001).

DISCUSSION

This pilot study demonstrates that variants in vitamin D metabolism genes are associated with quantitative asthma characteristics in young, urban AAs. The collection of these associations provides evidence for the need for a large population-based study of vitamin D-relevant SNPs in this cohort.

Associations between genetic variants in vitamin D metabolism and asthma characteristics in young African Americans: a pilot study

INTRODUCTION

Low vitamin D levels have been associated with asthma severity in children. Young, urban African Americans (AAs) have high rates of hypovitaminosis D and asthma. Our objective was to determine associations between variants in vitamin D metabolism genes and asthma characteristics in a pilot study of young urban AAs.

MATERIALS AND METHODS

Two urban AA cohorts of subjects aged 6 to 20 years (139 subjects with asthma and 74 subjects without asthma) were genotyped for 12 single nucleotide polymorphisms (SNPs) in 3 vitamin D metabolism genes: VDR (vitamin D receptor), CYP24A1 (cytochrome P450 vitamin D 24-hydroxylase), and CYP2R1 (cytochrome P450 vitamin D 25-hydroxylase). In a case-control analysis, SNPs were studied for associations with an asthma diagnosis. Within the asthmatic cohort, SNPs were analyzed for associations with quantitative asthma characteristics. All analyses were adjusted for age, sex, and body mass index percentile.

RESULTS

Only the CYP2R1 SNP rs10766197 homozygous minor genotype was associated with asthma (P = 0.044). CYP24A1 SNP rs2248137 was associated with lower vitamin D levels (P = 0.006). Within the asthma cohort, multiple significant associations between SNPs and asthma characteristics were identified; VDR SNP rs2228570 was associated with the higher nighttime asthma morbidity scores (P = 0.04), lower baseline spirometric measures (P < 0.05), 1 or more positive aeroallergen skin test (P = 0.003), and increased immunoglobulin E levels (P < 0.001).

DISCUSSION

This pilot study demonstrates that variants in vitamin D metabolism genes are associated with quantitative asthma characteristics in young, urban AAs. The collection of these associations provides evidence for the need for a large population-based study of vitamin D-relevant SNPs in this cohort.

Asthmatic airway epithelium is intrinsically inflammatory and mitotically dyssynchronous

Asthma is an inflammatory condition for which anti-inflammatory glucocorticoids are the standard of care. However, similar efficacy has not been shown for agents targeting inflammatory cells and pathways. This suggests a noninflammatory cell contributor (e.g., epithelium) to asthmatic inflammation. Herein, we sought to define the intrinsic and glucocorticoid-affected properties of asthmatic airway epithelium compared with normal epithelium. Human primary differentiated normal and asthmatic airway epithelia were cultured in glucocorticoid-free medium beginning at -48 hours. They were pulsed with dexamethasone (20 nM) or vehicle for 2 hours at -26, -2, +22, and +46 hours. Cultures were mechanically scrape-wounded at 0 hours and exposed continuously to bromodeoxyuridine (BrdU). Cytokine secretions were analyzed using cytometric bead assays. Wound regeneration/mitosis was analyzed by microscopy and flow cytometry. Quiescent normal (n = 3) and asthmatic (n = 6) epithelia showed similar minimal inflammatory cytokine secretion and mitotic indices. After wounding, asthmatic epithelia secreted more basolateral TGF-β1, IL-10, IL-13, and IL-1β (P < 0.05) and regenerated less efficiently than normal epithelia (+48 h wound area reduction = [mean ± SEM] 50.2 ± 7.5% versus 78.6 ± 7.7%; P = 0.02). Asthmatic epithelia showed 40% fewer BrdU(+) cells at +48 hours (0.32 ± 0.05% versus 0.56 ± 0.07% of total cells; P = 0.03), and those cells were more dyssynchronously distributed along the cell cycle (52 ± 10, 25 ± 4, 23 ± 7% for G1/G0, S, and G2/M, respectively) than normal epithelia (71 ± 1, 12 ± 2, and 17 ± 2% for G1/G0, S, and G2/M, respectively). Dexamethasone pulses improved asthmatic epithelial inflammation and regeneration/mitosis. In summary, we show that inflammatory/fibrogenic cytokine secretions are correlated with dyssynchronous mitosis upon injury. Intermittent glucocorticoids simultaneously decreased epithelial cytokine secretions and resynchronized mitosis. These data, generated in an airway model lacking inflammatory cells, support the concept that epithelium contributes to asthmatic inflammation.

High prevalence of vitamin D deficiency among inner-city African American youth with asthma in Washington, DC

OBJECTIVE

The goal of this study was to examine the prevalence of vitamin D insufficiency and deficiency among urban African-American (AA) youth with asthma compared with control subjects without asthma.

STUDY DESIGN

A cross-sectional case-control study was conducted at an urban pediatric medical center. Total 25-hydroxyvitamin D insufficiency (<30 ng/mL) and deficiency (<20 ng/mL) were assessed in urban self-reported AA patients, aged 6 to 20 years, with (n = 92) and without (n = 21) physician-diagnosed asthma.

RESULTS

Blood samples were available for 85 (92%) cases. The prevalence of vitamin D insufficiency and deficiency were significantly greater among cases than control subjects (73/85 [86%] vs 4/21 [19%], adjusted odds ratio = 42 [95% confidence interval: 4.4 to 399] for insufficiency and 46/85 [54%] vs 1/21 [5%], adjusted odds ratio = 20 [95% confidence interval: 1.4 to 272] for deficiency).

CONCLUSIONS

Most of this sample of urban AA youth with persistent asthma were vitamin D deficient or insufficient. Given the emerging associations between low vitamin D levels and asthma, strong consideration should be given to routine vitamin D testing in urban AA youth, particularly those with asthma.

Alpha 1-antitrypsin serum levels in widespread bronchiectasis

This study found significantly higher serum levels of alpha 1-antitrypsin (alpha 1-AT) in 35 patients with widespread bronchiectasis compared with healthy controls. The results are in contradiction with a previous study and four case reports which found an association between alpha 1-AT deficiency and bronchiectasis. However, the validity of the association has been questioned in the literature on the grounds that most of the patients in those reports had other possible aetiologies for their bronchiectasis. We believe the raised level of alpha 1-AT in our patients represents a non-specific acute phase response to bronchial infection. Further studies are needed to clarify whether bronchiectasis, like emphysema, can be a manifestation of alpha 1-AT deficiency.

Septicaemia caused by Vibrio vulnificus

Vibrio vulnificus is an uncommon cause of septicaemia. A few reports suggest that patients with chronic liver disease are more susceptible. We report two cases of septicaemia caused by this organism and emphasise the need for early empirical therapy.

The "lung shift" in treated schistosomiasis. Bronchoalveolar lavage evidence of eosinophilic pneumonia

There is conflicting and incomplete information in the literature on the pulmonary reaction which can occur following treatment of schistosomiasis. We examined the pulmonary function, bronchoalveolar lavage profile, and lung histopathology of a patient with pneumonia and peripheral eosinophilia following oxaminquine chemotherapy for intestinal Schistosoma mansoni infection. Spirometry revealed restrictive rather than obstructive impairment, and lavage showed eosinophil prominence which was also seen in the interstitial and alveolar-filling process in transbronchial biopsies.

Persisting "asthma" in tropical pulmonary eosinophilia

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