Background: Some children with asthma remain poorly controlled and have recurrent exacerbations despite treatment with inhaled corticosteroids. Aside from prior exacerbations, there are currently no reliable predictors of exacerbation-prone asthma in these children and limited understanding of potential underlying mechanisms. Objective: We sought to quantify small molecules in the plasma of children with exacerbation-prone asthma through mass spectrometry-based metabolomics. We hypothesized that the plasma metabolome of these children would differ from that of children with non-exacerbation-prone asthma. Methods: Plasma metabolites were extracted from four pediatric asthma cohorts (n=215 total, n=41 with exacerbation-prone asthma) and detected using a ZIC-HILIC column coupled to a Q Exactive HF mass spectrometer. High-confidence annotations were retained for univariate analysis and were confirmed by a sensitivity analysis in subjects on high-dose inhaled corticosteroids. Metabolites that varied by cohort were excluded. Metaboanalyst was used to identify pathways of interest. Concentrations were calculated by reference standardization to NIST SRM 1950. Results: We identified 32 unique, cohort-independent metabolites that differed in children with exacerbation-prone asthma compared to children with non-exacerbation-prone asthma. Comparison of metabolite concentrations to literature-reported values for healthy children revealed that most metabolites were decreased in both asthma groups, but more so in exacerbation-prone asthma. Pathway analysis identified arginine, lysine, and methionine pathways as most impacted. Conclusions: Several plasma metabolites are perturbed in children with exacerbation-prone asthma and are largely related to arginine, lysine, and methionine pathways. While validation is needed, plasma metabolites may be potential biomarkers for exacerbation-prone asthma in children.

Background: Asthma exacerbations are highly prevalent in children, but only a few studies have examined the biologic mechanisms underlying exacerbations in this population. Objective: High-resolution metabolomics analyses were performed to understand the differences in metabolites in children with exacerbating asthma who were hospitalized in a pediatric intensive care unit for status asthmaticus. We hypothesized that compared with a similar population of stable outpatients with asthma, children with exacerbating asthma would have differing metabolite abundance patterns with distinct clustering profiles. Methods: A total of 98 children aged 6 through 17 years with exacerbating asthma (n = 69) and stable asthma (n = 29) underwent clinical characterization procedures and submitted plasma samples for metabolomic analyses. High-confidence metabolites were retained and utilized for pathway enrichment analyses to identify the most relevant metabolic pathways that discriminated between groups. Results: In all, 118 and 131 high-confidence metabolites were identified in positive and negative ionization mode, respectively. A total of 103 unique metabolites differed significantly between children with exacerbating asthma and children with stable asthma. In all, 8 significantly enriched pathways that were largely associated with alterations in arginine, phenylalanine, and glycine metabolism were identified. However, other metabolites and pathways of interest were also identified. Conclusion: Metabolomic analyses identified multiple perturbed metabolites and pathways that discriminated children with exacerbating asthma who were hospitalized for status asthmaticus. These results highlight the complex biology of inflammation in children with exacerbating asthma and argue for additional studies of the metabolic determinants of asthma exacerbations in children because many of the identified metabolites of interest may be amenable to targeted interventions.

OBJECTIVES: Poverty, racial bias, and disparities are linked to adverse health outcomes for children in the United States. The social vulnerability and child opportunity indices are composite measures of the social, economic, education, health, and environmental qualities that affect human health for every U.S. census tract. Composite measures of social vulnerability and child opportunity were compared for neighborhood hot spots, where PICU admissions for acute respiratory failure requiring invasive mechanical ventilation were at the 90th percentile or greater per 1,000 children, versus non-hot spots. DESIGN: Population-based ecological study. SETTING: Two urban free-standing children's hospital PICUs consisting of a 36-bed quaternary academic and a 56-bed tertiary community center, in Atlanta, GA. PATIENTS: Mechanically ventilated children who were 17 years of age or younger with a geocodable Georgia residential address admitted to a PICU for at least 1 day. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Residential addresses were geocoded and spatially joined to census tracts. Composite measures of social vulnerability and childhood opportunity, PICU readmission rates, and hospital length of stay were compared between neighborhood hot spots versus non-hot spots. There were 340 of 3,514 children (9.7%) who lived within a hot spot. Hot spots were associated with a higher (worse) composite social vulnerability index ranking, reflecting differences in socioeconomic status, household composition and disability, and housing type and transportation. Hot spots also had a lower (worse) composite childhood opportunity index percentile ranking, reflecting differences in the education, health and environment, and social and economic domains. Higher social vulnerability and lower childhood opportunity were not associated with readmission rates but were associated with longer total median duration of hospital days per 1,000 children in a census tract. CONCLUSIONS: Social determinants of health identified by geospatial analyses are associated with acute respiratory failure requiring invasive mechanical ventilation in critically ill children. Interventions addressing the neighborhood social vulnerability and child opportunity are needed to decrease disparities in intensive care admissions for acute respiratory failure requiring mechanical ventilation.

Introduction Female cancer survivors who received gonadotoxic cancer treatment are at risk for profound diminished ovarian reserve and/or primary ovarian insufficiency with resulting infertility, which can be associated with distress and decreased quality of life.. Despite prioritizing future parenthood, many survivors are unsure of the impact of their treatment on their future fertility, and little is known about the perceived reproductive health needs and factors associated with receipt of a fertility status assessment (FSA). There is a lack of developmentally appropriate reproductive health decisional support interventions available for emerging adult cancer survivors. This study will explore the perceived reproductive health needs of emerging adult female survivors of childhood cancer and to identify decisional and contextual factors that influence pursuit of FSA using an explanatory sequential quantitative to qualitative mixed methods design. Methods and analysis This study will enroll 325 female survivors (aged 18 to 29 years and >1-year post treatment; diagnosed with cancer < age 21 years) from four cancer centers in the United States. Sociodemographic and developmental factors, reproductive knowledge and values, decisional needs, and receipt of an FSA will be assessed through a web-based survey. Informed by survey findings, a subset of participants will be recruited for qualitative interviews to explore decisional factors associated with uptake of an FSA. Clinical data will be abstracted from the medical records. Multivariable logistic regression models will be developed to identify factors associated with FSA and qualitative descriptive analysis will be used to develop themes from the interviews. Quantitative and qualitative findings will be merged using a joint display to develop integrated study conclusions and direct future interventional research.

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Introduction: FEF25-75 is one of the standard results provided in spirometry reports; however, in adult asthmatics there is limited information on how this physiological measure relates to clinical or biological outcomes independently of the FEV1 or the FEV1/FVC ratio. Purpose: To determine the association between Hankinson's percent-predicted FEF25-75 (FEF25-75%) levels with changes in healthcare utilization, respiratory symptom frequency, and biomarkers of distal airway inflammation. Methods: In participants enrolled in the Severe Asthma Research Program 1-2, we compared outcomes across FEF25-75% quartiles. Multivariable analyses were done to avoid confounding by demographic characteristics, FEV1, and the FEV1/FVC ratio. In a sensitivity analysis, we also compared outcomes across participants with FEF25-75% below the lower limit of normal (LLN) and FEV1/FVC above LLN. Results: Subjects in the lowest FEF25-75% quartile had greater rates of healthcare utilization and higher exhaled nitric oxide and sputum eosinophils. In multivariable analysis, being in the lowest FEF25-75% quartile remained significantly associated with nocturnal symptoms (OR 3.0 [95%CI 1.3-6.9]), persistent symptoms (OR 3.3 [95%CI 1-11], ICU admission for asthma (3.7 [1.3-10.8]) and blood eosinophil % (0.18 [0.07, 0.29]). In the sensitivity analysis, those with FEF25-75% <LLN had significantly more nocturnal and persistent symptoms, emergency room visits, higher serum eosinophil levels and increased methacholine responsiveness. Conclusions: After controlling for demographic variables, FEV1 and FEV1/FVC, a reduced FEF25-75% is independently associated with previous ICU admission, persistent symptoms, nocturnal symptoms, blood eosinophilia and bronchial hyperreactivity. This suggests that in some asthmatics, a reduced FEF25-75% is an independent biomarker for more severe asthma.

Background: Noninvasive markers of type 2 inflammation are needed to identify children and adolescents who might benefit from personalized biologic therapy. Objective: We hypothesized that blood eosinophil counts would predict 1 or more acute visits for asthma and that prediction could be improved with the addition of a second, noninvasive type 2 inflammatory biomarker. Methods: Children and adolescents 5 to 21 years (N = 589) with an asthma exacerbation necessitating systemic corticosteroid treatment in the previous year completed a characterization visit and telephone calls at 6 and 12 months. The primary outcome was an acute visit for asthma with receipt of systemic corticosteroids. Acute visits were verified by medical record review. Exploratory outcomes included time to first acute visit and hospitalization. Results: Acute visits occurred in 106 (35.5%) children and 72 (24.8%) adolescents. Elevated blood eosinophils were associated with increased odds and shorter time to first acute visit, but optimal cut-points differed by age (≥150 vs ≥300 cells/μL for children vs adolescents, respectively). The addition of a second marker of type 2 inflammation did not improve prediction in children, but increased the odds and hazard of an acute visit up to 16.2% and 11.9%, respectively, in adolescents. Similar trends were noted for hospitalizations. Conclusions: Blood eosinophils and other noninvasive markers of type 2 inflammation may be useful in the clinical assessment of children and adolescents with asthma. However, features of type 2 inflammation vary by age. Whether children and adolescents also respond differently to management of type 2 inflammation is unclear and warrants further evaluation.

Background: Our objective was to determine those characteristics associated with reversibility of airflow obstruction and response to maximal bronchodilation in children with severe asthma through the Severe Asthma Research Program (SARP). Methods: We performed a cross-sectional analysis evaluating children ages 6–17 years with non-severe (NSA) and severe asthma (SA). Participants underwent spirometry before and after 180 μg of albuterol to determine reversibility (≥12% increase in FEV1). Participants were then given escalating doses up to 720 μg of albuterol to determine their maximum reversibility. Results: We evaluated 230 children (n=129 SA, n=101 NSA) from 5 centers across the U.S. in the SARP I and II cohorts. SA (OR 2.08, 95%CI 1.05 to 4.13), second-hand smoke exposure (OR 2.81, 95%CI 1.23 to 6.43), and FeNO (OR 1.97, 95%CI 1.35 to 2.87) were associated with increased odds of airway reversibility after maximal bronchodilation, while higher pre-bronchodilator FEV1% predicted (OR 0.91, 95%CI 0.88 to 0.94) was associated with decreased odds. In an analysis using the SARP III cohort (n=186), blood neutrophils, IgE and FEV1% predicted were significantly associated with bronchodilator reversibility. In addition, children with bronchodilator response have greater healthcare utilization. Bronchodilator reversibility was associated with reduced lung function at enrollment and one-year follow-up though less decline in lung function over one year compared to those without reversibility. Conclusions: Lung function, that is FEV1 % predicted, is a predictor of bronchodilator response in children with asthma. Additionally, smoke exposure, higher FeNO or IgE level, and low peripheral blood neutrophils are associated with greater likelihood of bronchodilator reversibility. Bronchodilator response can identify a phenotype of pediatric asthma associated with low lung function and poor asthma control.

Acute respiratory distress syndrome (ARDS) is a heterogeneous condition characterized by the recruitment of large numbers of neutrophils into the lungs. Neutrophils isolated from the blood of adults with ARDS have elevated expression of interferon (IFN) stimulated genes (ISGs) associated with decreased capacity of neutrophils to kill Staphylococcus aureus and worse clinical outcomes. Neutrophil extracellular traps (NETs) are elevated in adults with ARDS. Whether pediatric ARDS (PARDS) is similarly associated with altered neutrophil expression of ISGs and neutrophil extracellular trap release is not known. Tracheal aspirate fluid and cells were collected within 72 h from seventy-seven intubated children. Primary airway neutrophils were analyzed for differential ISG expression by PCR, STAT1 phosphorylation and markers of degranulation and activation by flow cytometry. Airway fluid was analyzed for the release of NETs by myeloperoxidase-DNA complexes using an ELISA. Higher STAT1 phosphorylation, markers of neutrophil degranulation, activation and NET release were found in children with versus without PARDS. Higher NETs were detected in the airways of children with ventilator-free days less than 20 days. Increased airway cell IFN signaling, neutrophil activation, and NET production is associated with PARDS. Higher levels of airway NETs are associated with fewer ventilator-free days.

Background Although the clinical attributes of severe asthma in children have been well described, the differentiating features of the lower airway inflammatory response. Objectives We sought to discriminate severe from moderate asthma in children by applying linear discriminant analysis, a supervised method of high-dimensional data reduction, to cytokines and chemokines measured in the bronchoalveolar lavage (BAL) fluid and alveolar macrophage (AM) lysate. Methods BAL fluid was available from 53 asthmatic children (severe asthma, n = 31) undergoing bronchoscopy for clinical indications and 30 non-smoking adults. 23 cytokines and chemokines were measured using bead-based multiplex assays. Linear discriminant analyses of the BAL fluid and AM analytes were performed to develop predictive models of severe asthma in children. Results Although univariate analysis of single analytes did not differentiate severe from moderate asthma in children, linear discriminant analyses allowed for near complete separation of the moderate and severe asthmatic groups. Significant correlations were also noted between several of the AM and BAL analytes measured. In the BAL fluid, IL-13 and IL-6 differentiated asthmatics from controls, whereas GRO (CXCL1), RANTES (CCL5), IL-12, IFNγ, and IL-10 best characterized severe versus moderate asthma in children. In the AM lysate, IL-6 was the strongest discriminator of all the groups. Conclusions Severe asthma in children is characterized by a distinct airway molecular phenotype that does not have a clear Th1 or Th2 pattern. Improved classification of children with severe asthma may assist with the development of targeted therapeutics for this group of children who are difficult to treat.

Background: Children with severe asthma have poor symptom control and elevated markers of airway oxidative and nitrosative stress. Paradoxically, they have decreased airway levels of S-nitrosothiols (SNOs), a class of endogenous airway smooth muscle relaxants. This deficiency results from increased activity of an enzyme that both reduces SNOs to ammonia and oxidizes formaldehyde to formic acid, a volatile carboxylic acid that is more easily detected in exhaled breath condensate (EBC) than SNOs. We therefore hypothesize that depletion of airway SNOs is related to asthma pathology, and breath formate concentration may be a proxy measure of SNO catabolism. Methods and Findings: We collected EBC samples from children and adolescents, including 38 with severe asthma, 46 with mild-to-moderate asthma and 16 healthy adolescent controls, and the concentration of ionic constituents was quantified using ion chromatography. The concentrations of EBC components with volatile conjugates were log-normally distributed. Formate was the principal ion that displayed a significant difference between asthma status classifications. The mean EBC formate concentration was 40% higher in samples collected from all asthmatics than from healthy controls (mean = 5.7 µM, mean±standard deviation = 3.1−10.3 µM vs. 4.0, 2.8−5.8 µM, p = 0.05). EBC formate was higher in severe asthmatics than in mild-to-moderate asthmatics (6.8, 3.7−12.3 µM vs. 4.9, 2.8−8.7 µM, p = 0.012). In addition, formate concentration was negatively correlated with methacholine PC20 (r = −0.39, p = 0.002, asthmatics only), and positively correlated with the NO-derived ion nitrite (r = 0.46, p<0.0001) as well as with total serum IgE (r = 0.28, p = 0.016, asthmatics only). Furthermore, formate was not significantly correlated with other volatile organic acids nor with inhaled corticosteroid dose. Conclusions: We conclude that EBC formate concentration is significantly higher in the breath of children with asthma than in those without asthma. In addition, amongst asthmatics, formate is elevated in the breath of those with severe asthma compared to those with mild-to-moderate asthma. We suggest that this difference is related to asthma pathology and may be a product of increased catabolism of endogenous S-nitrosothiols.