Exhaled Nitric Oxide Concentration Research Articles

Association between PM2.5 from a coal mine fire and FeNO concentration 7.5 years later

Background and aimThere are few long-term studies of respiratory health effects of landscape fires, despite increasing frequency and intensity due to climate change. We investigated the association between exposure to coal mine fire PM2.5 and fractional exhaled nitric oxide (FeNO) concentration 7.5 years later.MethodsAdult residents of Morwell, who were exposed to the 2014 Hazelwood mine fire over 6 weeks, and unexposed residents of Sale, participated in the Hazelwood Health Study Respiratory Stream in 2021, including measurements of FeNO concentration, a marker of eosinophilic airway inflammation. Individual exposure to coal mine fire PM2.5 was modelled and mapped to time-location diaries. The effect of exposure to PM2.5 on log-transformed FeNO in exhaled breath was investigated using multivariate linear regression models in the entire sample and stratified by potentially vulnerable subgroups.ResultsA total of 326 adults (mean age: 57 years) had FeNO measured. The median FeNO level (interquartile range [IQR]) was 17.5 [15.0] ppb, and individual daily exposure to coal mine fire PM2.5 was 7.2 [13.8] µg/m3. We did not identify evidence of association between coal mine fire PM2.5 exposure and FeNO in the general adult sample, nor in various potentially vulnerable subgroups. The point estimates were consistently close to zero in the total sample and subgroups.ConclusionDespite previous short-term impacts on FeNO and respiratory health outcomes in the medium term, we found no evidence that PM2.5 from the Hazelwood coal mine fire was associated with any long-term impact on eosinophilic airway inflammation measured by FeNO levels.

The Effects of High Intensity Interval Training (HIIT) on Asthmatic Adult Males

Background – This study explored the effects of High-Intensity Interval Training (HIIT) on pulmonary function, exercise tolerance, and fractional concentration of exhaled nitric oxide (FeNO) in asthmatic and healthy adults. FeNO levels, associated with lung inflammation, are a diagnostic tool for asthma treatment, making this study significant for understanding HIIT's impact on asthma management. Materials and Methods: Fourteen male subjects (7 asthmatic, 7 healthy) participated in a two-week HIIT protocol. Pulmonary function was assessed using peak expiratory flow (PEF), forced vital capacity (FVC), and the FEV1/FVC ratio. FeNO was measured with a NIOX portable device. Subjects underwent a progressive exercise test on a cycle ergometer to determine peak oxygen uptake (VO2 peak), CO2 output (VCO2 peak), ventilation (VE), and time to exhaustion (TTE). HIIT sessions included warm-ups, 10 x 60-second high-intensity bouts with 60-second recovery intervals, and cool-downs. Intensity targeted 75% peak work rate (WR) for asthmatics and 80% for controls. Results: Significant differences were observed between groups in FeNO, VO2 peak, TTE, and peak WR, with no significant changes in pulmonary function measures. Pre-HIIT, asthmatics showed a mean FeNO of 28 ± 2 ppb compared to controls at 18 ± 1 ppb, with post-HIIT levels remaining stable. TTE and peak WR improved in both groups post-HIIT, indicating enhanced exercise tolerance and performance capacity. Specifically, asthmatics showed an increase in TTE from 691 ± 40 s to 781 ± 41 s and in peak WR from 175 ± 13 W to 203 ± 14 W. Conclusion: HIIT was well-tolerated by asthmatic subjects, leading to improved exercise tolerance, higher ventilation, CO2 output, and work rate performance, without significant changes in pulmonary function or FeNO levels. These findings suggest that HIIT can be a safe and effective exercise intervention for asthmatic individuals to enhance exercise performance.

Identification and treatment of persistent small airway dysfunction in paediatric patients with asthma: a retrospective cohort study

BackgroundAsthma is a common respiratory disease. In asthma, the small airways have more intensive inflammation and prominent airway remodelling, compared to the central airways. We aimed to investigate the predictive value of risk factors and the fractional concentration of exhaled nitric oxide (FeNO) for persistent small airway dysfunction (p-SAD), and compare the effects of different treatment modalities.MethodsThis retrospective cohort study included 248 children with asthma (aged 4–11 years). Binary logistic regression was used to analyse the risk factors for p-SAD. Correlations among FEV1/FVC, small airway function parameters, and FeNO levels in patients with asthma were analysed using Spearman’s rank correlation. The receiver operating characteristic curve and the Delong test were used to analyse the predictive value of FeNO for p-SAD. Differences in the treatment effects of inhaled corticosteroids (ICS) and ICS with a long-acting beta-agonist (ICS/LABA) on p-SAD were analysed using Fisher’s exact test.ResultsAsthmatic children with older age of receiving the regular treatment (OR 1.782, 95% CI 1.082–2.935), with younger age at the time of onset of suspected asthma symptoms (OR 0.602, 95% CI 0.365–0.993), with longer duration of using ICS or ICS/LABA (OR 1.642, 95% CI 1.170–2.305) and with worse asthma control (OR 3.893, 95% CI 1.699–8.922) had increased risk for p-SAD. Significant negative correlations of small airway function parameters with FeNO at a 200 mL/s flow rate (FeNO200), and the concentration of nitric oxide in the alveolar or acinar region (CaNO) were observed. The areas under the curve of FeNO200 (cut-off:10.5ppb), CaNO (cut-off:5.1ppb), and FeNO200 combined with CaNO were 0.743, 0.697, and 0.750, respectively, for asthma with p-SAD. After using ICS or ICS/LABA, switching to ICS/LABA was easier than continuing with ICS to improve small airway dysfunction (SAD) in the 8th month.ConclusionsPaediatric asthma with p-SAD is associated with older age at receiving regular treatment, younger age at the time of onset of suspected asthma symptoms, longer duration of using ICS or ICS/LABA, worse asthma control, and higher FeNO200 and CaNO levels, all of which can be combined with small airway function indicators to distinguish p-SAD from asthma. ICS/LABA improves SAD better than ICS alone.

Ultrasensitive Online NO Sensor Based on a Distributed Parallel Self-Regulating Neural Network and Ultraviolet Differential Optical Absorption Spectroscopy for Exhaled Breath Diagnosis.

The concentration of fractional exhaled nitric oxide (FeNO) is closely related to human respiratory inflammation, and the detection of its concentration plays a key role in aiding diagnosing inflammatory airway diseases. In this paper, we report a gas sensor system based on a distributed parallel self-regulating neural network (DPSRNN) model combined with ultraviolet differential optical absorption spectroscopy for detecting ppb-level FeNO concentrations. The noise signals in the spectrum are eliminated by discrete wavelet transform. The DPSRNN model is then built based on the separated multipeak characteristic absorption structure of the UV absorption spectrum of NO. Furthermore, a distributed parallel network structure is built based on each absorption feature region, which is given self-regulating weights and finally trained by a unified model structure. The final self-regulating weights obtained by the model indicate that each absorption feature region contributes a different weight to the concentration prediction. Compared with the regular convolutional neural network model structure, the proposed model has better performance by considering the effect of separated characteristic absorptions in the spectrum on the concentration and breaking the habit of bringing the spectrum as a whole into the model training in previous related studies. Lab-based results show that the sensor system can stably achieve high-precision detection of NO (2.59-750.66 ppb) with a mean absolute error of 0.17 ppb and a measurement accuracy of 0.84%, which is the best result to date. More interestingly, the proposed sensor system is capable of achieving high-precision online detection of FeNO, as confirmed by the exhaled breath analysis.

Effects of training flights of combat jet pilots on parameters of airway function, diffusing capacity and systemic oxidative stress, and their association with flight parameters

BackgroundFighter aircraft pilots are regularly exposed to physiological challenges from high acceleration (Gz) forces, as well as increased breathing pressure and oxygen supply in the support systems. We studied whether effects on the lung and systemic oxidative stress were detectable after real training flights comprising of a wide variety of exposure conditions, and their combinations.MethodsThirty-five pilots of the German Air Force performed 145 flights with the Eurofighter Typhoon. Prior to and after flight lung diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO), alveolar volume (VA), and diffusing capacities per volume (KCO, KNO) were assessed. In addition, the fractional concentration of exhaled nitric oxide (FeNO) was determined, and urine samples for the analysis of molecular species related to 8-hydroxy-2’-deoxyguanosine (8-OHdG) were taken. For statistical analysis, mixed ANOVA models were used.ResultsDLNO, DLCO, KNO, KCO and VA were reduced (p < 0.001) after flights, mean ± SD changes being 2.9 ± 5.0, 3.2 ± 5.2, 1.5 ± 3.7, 1.9 ± 3.7 and 1.4 ± 3.1%, respectively, while FeNO decreased by 11.1% and the ratio of 8-OHdG to creatinine increased by 15.7 ± 37.8%. The reductions of DLNO (DLCO) were smaller (p < 0.001) than those of KNO (KCO). In repeated flights on different days, baseline values were restored. Amongst various flight parameters comprising Gz-forces and/or being indicative of positive pressure breathing and oxygenation support, the combination of long flight duration and high altitude appeared to be linked to greater changes in DLNO and DLCO.ConclusionsThe pattern of reductions in diffusing capacities suggests effects arising from atelectasis and increased diffusion barrier, without changes in capillary blood volume. The decrease in exhaled endogenous NO suggests bronchial mucosal irritation and/or local oxidative stress, and the increase in urinary oxidized guanosine species suggests systemic oxidative stress. Although changes were small and not clinically relevant, their presence demonstrated physiological effects of real training flights in a modern 4th generation fighter jet.

Efficacy of dupilumab and risk factors for dupilumab-induced hypereosinophilia in severe asthma: a preliminary study from China

Objective Dupilumab has been approved for the treatment of severe asthma with type 2 inflammation by inhibiting interleukin (IL)-4 and IL-13 signaling. However, dupilumab-induced hypereosinophilia (HE) has been reported and should not be ignored. The aim of this study was to investigate the efficacy of dupilumab in Chinese patients with severe asthma, whether HE affects its efficacy, and the possible risk factors for HE. Methods 20 patients with severe asthma who received dupilumab treatment for at least 12 months in the First Affiliated Hospital of Guangzhou Medical University from 2019 to 2022 were included. We compared clinical data and laboratory tests results before dupilumab treatment and at 4 and 12 months after treatment. Based on whether dupilumab treatment triggers HE defined as blood eosinophil count (BEC) ≥ 1.5 × 109 cells/L, the patients were allocated into non-HE and HE groups. Results The patients showed a significant increase in asthma control test (ACT) scores, a decrease in the number of exacerbations, a decrease in the proportion of patients taking an oral corticosteroid (OCS) and in the dose, and a significant improvement in the pulmonary function parameters FEV1/FVC (%) and FEV1 (% predicted) after 4 and 12 months of treatment with dupilumab. For type 2 inflammatory biomarkers, the levels of fractional concentration of exhaled nitric oxide (FeNO), sputum eosinophil count percentage (SEC%) and total immunoglobulin E (TIgE) decreased significantly, whereas BEC were higher after 4 months of treatment, but returned to baseline levels after 12 months. 8 patients (40%) developed asymptomatic HE after dupilumab, and the efficacy was not significantly different between the HE and non-HE groups. The earliest BEC elevation appeared at 1 month after treatment, but most of them declined after 6 months, and basically returned to the baseline level around 12 months of treatment. In addition, we further found that when patients had FeNO ≥ 60 ppb, food allergens positive and combined eosinophilic otitis media (EOM), their BEC increased significantly more than that of the control group after 4 months as well as 12 months of treatment. Conclusions This study demonstrated that dupilumab was efficacious in Chinese patients with severe asthma, and some patients developed asymptomatic, self-limited HE, which did not affect its efficacy. Additionally, FeNO ≥60 ppb, food allergens positive, and co-morbidities with EOM may be the risk factors for developing HE.

Mepolizumab in children and adolescents with severe eosinophilic asthma not eligible for omalizumab: a single Center experience

Background Mepolizumab is an anti-interleukin-5 monoclonal antibody shown to reduce asthma exacerbations in adults and adolescents with severe eosinophilic asthma. Aim To assess the impact of mepolizumab on children and adolescents over 12 months by examining steroid usage, asthma-related hospitalizations, Asthma Control Test (ACT) scores, fractional exhaled nitric oxide concentration (FeNO), forced expiratory volume in 1 s (FEV1), mid expiratory flow (FEF25–75%), and blood eosinophil count. Methods Retrospective analysis performed between October 2015 and December 2022. Data was reviewed 12 months before and after commencing mepolizumab. Mepolizumab was offered if the patient had severe eosinophilic asthma and were unresponsive to or ineligible for omalizumab. Results Sixteen participants (age 7–17, 8 males, 8 females) received subcutaneous mepolizumab monthly with no serious adverse reactions. Incidence of hospital admissions fell significantly (IRR 0.33, p = 0.007). Among the 11 patients receiving daily oral corticosteroids, 3 were weaned off daily oral steroids and 3 patients’ daily dose was significantly reduced (mean Δ-0.095 ± 0.071 mg/kg, p = 0.0012). Eosinophil count was decreased (mean Δ-0.85 x 109/L, p < 0.001). There was no significant change in mean overall steroid burden per patient (mean Δ-1445.63 ± 1603.18 mg, p = 0.10), ACT scores (mean Δ2.88 ± 6.71, p = 0.17), FEV1 z-scores (mean Δ-0.99 ± 1.88, p = 0.053), FEF25–75% z-scores (mean Δ-0.65 ± 1.61, p = 0.13), FeNO (mean Δ-20.09 ± 80.86, p = 0.34), or number of courses of oral steroids given for asthma attacks (IRR 0.71, p = 0.09). Conclusion Among children and adolescents with severe eosinophilic asthma ineligible for or not responsive to omalizumab, mepolizumab therapy exhibited significant reduction in rate of asthma-related hospitalizations and significant decrease in daily steroid dosage.

Exhaled nitric oxide in intubated ICU patients on mechanical ventilation—a feasibility study

It can be a clinical challenge to distinguish inflammation from infection in critically ill patients. Therefore, valid and conclusive surrogate markers for infections are desired. Nitric oxide (NO) might be that marker since concentrations of exhaled NO have shown to change in the presence of various diseases. This observational, prospective, single-center feasibility study aimed to investigate if fractional exhaled NO (FeNO) can be measured in intubated patients with or without infection, pneumonia and septic shock in a standardized, reliable setting. 20 intubated patients in the intensive care unit (ICU) were included for analysis. FeNO mean values were measured in the endotracheal tube via the suction channel using a chemiluminescence based analyzer. We developed a pragmatic method to measure FeNO repeatedly and reliably in intubated patients using a chemiluminescence based analyzer. We found a median of 0.98 (0.59–1.44) FeNO mean (ppb) in exhaled breath from all 20 intubated patient. Intubated patient with suspected infection had a significantly lower median FeNO mean compared with the intubated patients without suspected infection. Similarly did patients with septic shock demonstrate a significantly lower median FeNO mean than without septic shock. We found no statistical difference in median FeNO mean for intubated patients with pneumonia. It was feasible to measure FeNO in intubated patients in the ICU. Our results indicate decreased levels of FeNO in infected intubated patients in the ICU. The study was not powered to provide firm conclusions, so larger trials are needed to confirm the results and to prove FeNO as a useful biomarker for distinguishment between infection and inflammation in the ICU.

Clinical implications of the concentration of alveolar nitric oxide in non-small cell lung cancer.

Clinical implications of the concentration of alveolar nitric oxide in non-small cell lung cancer.

Use of digital measurement of medication adherence and lung function to guide the management of uncontrolled asthma (INCA Sun): a multicentre, single-blinded, randomised clinical trial

The clinical value of using digital tools to assess adherence and lung function in uncontrolled asthma is not known. We aimed to compare treatment decisions guided by digitally acquired data on adherence, inhaler technique, and peak flow with existing methods. A 32-week prospective, multicentre, single-blinded, parallel, randomly controlled trial was done in ten severe asthma clinics across Ireland, Northern Ireland, and England. Participants were 18 years or older, had uncontrolled asthma, asthma control test (ACT) score of 19 or less, despite treatment with high-dose inhaled corticosteroids, and had at least one severe exacerbation in the past year despite high-dose inhaled corticosteroids. Patients were randomly assigned in a 1:1 ratio to the active group or the control group, by means of a computer-generated randomisation sequence of permuted blocks of varying sizes (2, 4, and 6) stratified by fractional exhaled nitric oxide (FeNO) concentration and recruitment site. In the control group, participants were masked to their adherence and errors in inhaler technique data. A statistician masked to study allocation did the statistical analysis. After a 1-week run-in period, both groups attended three nurse-led education visits over 8 weeks (day 7, week 4, and week 8) and three physician-led treatment adjustment visits at weeks 8, 20, and 32. In the active group, treatment adjustments during the physician visits were informed by digital data on inhaler adherence, twice daily digital peak expiratory flow (ePEF), patient-reported asthma control, and exacerbation history. Treatment was adjusted in the control group on the basis of pharmacy refill rates (a measure of adherence), asthma control by ACT questionnaire, and history of exacerbations and visual management of inhaler technique. Both groups used a digitally enabled Inhaler Compliance Assessment (INCA) and PEF. The primary outcomes were asthma medication burden measured as proportion of patients who required a net increase in treatment at the end of 32 weeks and adherence rate measured in the last 12 weeks by area under the curve in the intention-to-treat population. The safety analyses included all patients who consented for the trial. The trial is registered with ClinicalTrials.gov, NCT02307669 and is complete. Between Oct 25, 2015, and Jan 26, 2020, of 425 patients assessed for eligibility, 220 consented to participate in the study, 213 were randomly assigned (n=108 in the active group; n=105 in the control group) and 200 completed the study (n=102 in the active group; n=98 in the control group). In the intention-to-treat analysis at week 32, 14 (14%) active and 31 (32%) control patients had a net increase in treatment compared with baseline (odds ratio [OR] 0·31 [95% CI 0·15-0·64], p=0·0015) and 11 (11%) active and 21 (21%) controls required add-on biological therapy (0·42 [0·19-0·95], p=0·038) adjusted for study site, age, sex, and baseline FeNO. Three (16%) of 19 active and 11 (44%) of 25 control patients increased their medication from fluticasone propionate 500 μg daily to 1000 μg daily (500 μg twice a day; adjusted OR 0·23 [0·06-0·87], p=0·026). 26 (31%) of 83 active and 13 (18%) of 73 controls reduced their medication from fluticasone propionate 1000 μg once daily to 500 μg once daily (adjusted OR 2·43 [1·13-5·20], p=0·022. Week 20-32 actual mean adherence was 64·9% (SD 23·5) in the active group and 55·5% (26·8) in the control group (between-group difference 11·1% [95% CI 4·4-17·9], p=0·0012). A total of 29 serious adverse events were recorded (16 [55%] in the active group, and 13 [45%] in the control group), 11 of which were confirmed as respiratory. None of the adverse events reported were causally linked to the study intervention, to the use of salmeterol-fluticasone inhalers, or the use of the digital PEF or INCA. Evidence-based care informed by digital data led to a modest improvement in medication adherence and a significantly lower treatment burden. Health Research Board of Ireland, Medical Research Council, INTEREG Europe, and an investigator-initiated project grant from GlaxoSmithKline.

Clinical efficacy of omalizumab for treatment of moderate or severe allergic asthma in children with serum immunoglobulin E levels >1 500 IU/mL: a prospective study

To evaluate the clinical efficacy of omalizumab in the treatment of moderate or severe allergic asthma in children with serum total immunoglobulin E (IgE) levels >1 500 IU/mL. A total of 95 children with moderate or severe allergic asthma, who were treated at the Department of Respiratory Medicine in Anhui Provincial Children's Hospital from December 2020 to May 2022, were enrolled. Based on their serum total IgE levels and whether they received omalizumab treatment, they were divided into a control group (IgE >1 500 IU/mL, no omalizumab treatment), a normal treatment group (IgE levels between 30 and 1 500 IU/mL, omalizumab treatment), and an ultra-high IgE treatment group (IgE >1 500 IU/mL, omalizumab treatment). The differences in clinical characteristics, Childhood Asthma Control Test (C-ACT) scores before and after treatment, the proportion of acute attacks, IgE levels, pulmonary function indicators, and fractional exhaled nitric oxide (FeNO) concentrations were analyzed among the three groups. At the 8th week of treatment, the normal treatment group and the ultra-high IgE treatment group had higher C-ACT scores, forced expiratory volume in first second (FEV1) as a percentage of predicted value (FEV1%pred), FEV1/forced vital capacity (FVC) ratio (FEV1/FVC), and peak expiratory flow (PEF) as a percentage of predicted value (PEF%pred), as well as a lower proportion of acute attacks and FeNO concentration compared to the control group (P<0.05). There were no statistically significant differences in the comparison of various indicators between the ultra-high IgE treatment group and the normal treatment group (P>0.05). At the 16th week of treatment, the normal treatment group and the ultra-high IgE treatment group had higher C-ACT scores and pulmonary function indicators including FEV1%pred, FEV1/FVC, PEF%pred, and forced expiratory flow at 25% vital capacity (FEF25) as a percentage of predicted value (FEF25%pred) compared to the control group (P<0.05). The proportion of acute attacks and FeNO concentration in the ultra-high IgE treatment group were lower than those in the control group (P<0.05). There were no statistically significant differences in the comparison of various indicators between the ultra-high IgE treatment group and the normal treatment group (P>0.05). Omalizumab therapy has a certain clinical efficacy in children with moderate or severe allergic asthma and serum total IgE levels >1 500 IU/mL, with no significant difference in efficacy compared to children with serum total IgE levels between 30 and 1 500 IU/mL.

Is tezepelumab the ubiquitous biologic for severe asthma?

Biologic therapies have transformed severe asthma management.1 The use of these treatments has been based on the identification of specific phenotypic characteristics, which predict patient response to specific monoclonal antibody therapies. Measurements of total serum immunoglobulin (Ig)-E, blood eosinophil counts, and fractional concentration of exhaled nitric oxide (FeNO), enable the identification of specific type 2-high phenotypes responsive to specific biologic therapies. However, in clinical practice the paucity of biologics effective for both type 2-high and type 2-low asthma phenotypes is an important limitation of this therapeutic approach.

Evaluation of fractional exhaled nitric oxide in school-age children with asthma and sensitization to cat allergens

bronchial asthma is a chronic condition that is considerably prevalent among children. According to scientific evidence, cat allergens are most frequently responsible for the onset of asthma manifestations in children. Children are more likely to develop atopic asthma with eosinophilic inflammation. Under these circumstances, specific biomarkers are used as indicators of this inflammation. Fractional exhaled nitric oxide has been identified as a marker of eosinophilic airway inflammation in asthma. The aim of the research was to determine the fractional exhaled nitric oxide concentrations in school-age children with bronchial asthma and sensitization to cat allergens in order to predict asthma control status and assess therapeutic response. A total of 430 children aged between 6 and 17 years with asthma and sensitization to cat allergens participated in the study. The sensitization profile was investigated using a multicomponent molecular allergy diagnostic test (ALEX², Austria). The fractional exhaled nitric oxide levels were evaluated (NIOX VERO, Sweden). A total of 302 patients were enrolled in a retrospective study to find out how likely they were to gain bronchial asthma control over the course of therapy. As a result, a one-factor logistic regression analysis was conducted. A total of 128 children were included in the 12-month prospective research. All patients had a rise in fractional exhaled nitric oxide of &gt; 20 ppb, with children with severe asthma having levels of 35 ppb or higher. The study discovered that changes in the fractional exhaled nitric oxide concentrations at the end of a three-month therapy could be linked to the maintenance of bronchial asthma control after a 12-month treatment period (r = 0.619; p &lt;0.001). After a year of therapy, increasing baseline fractional exhaled nitric oxide levels reduced the probability of establishing bronchial asthma control in children (OR &lt;1; p &lt;0.001). The dynamics of fractional exhaled nitric oxide reduction increased the probability of achieving bronchial asthma control after completion of a three-month therapy (OR&gt; 1; p &lt;0.001). The effect of allergen-specific immunotherapy on the specified indicator of eosinophilic inflammation was demonstrated by a statistically significant difference in the mean values of fractional exhaled nitric oxide after a 12-month treatment period in the group of patients who received allergen-specific immunotherapy in combination with controller therapy versus the group of patients who received only controller therapy (p = 0.012). Thus, among school-age children with asthma and sensitization to cat allergens, the levels of fractional exhaled nitric oxide increased, especially in severe asthma. Not only the baseline fractional exhaled nitric oxide levels but also their dynamics after a three-month therapy should be considered when predicting the probability of establishing asthma control in these children. The inclusion of allergen-specific immunotherapy in the complex treatment of bronchial asthma in school-age children with sensitization to cat allergens has been shown to have a favourable therapeutic effect on the fractional exhaled nitric oxide levels.

Airway inflammation in adolescents and elderly women: Chronic air pollution exposure and polygenic susceptibility

Background and aimThe fractional exhaled nitric oxide (FeNO) concentration in the exhaled breath is a biomarker for eosinophilic airway inflammation. We explored the interplay between chronic air pollution exposure and polygenic susceptibility to airway inflammation at different critical age stages. MethodsAdolescents (15 yr) enrolled in the GINIplus/LISA birth cohorts (n = 2434) and 220 elderly women (75 yr on average) enrolled in the SALIA cohort with FeNO measurements available were investigated. Environmental main effects of the mean of ESCAPE land-use regression air pollutant concentrations within a time window of 15 years and main effects of the polygenic risk scores (PRS) using internal weights from elastic net regression of genome-wide derived single nucleotide polymorphisms were investigated. Furthermore, we examined gene-environment interaction (GxE) effects on natural log-transformed FeNO levels by adjusted linear regression models. ResultsWhile we observed no significant environmental and polygenic main effects on airway inflammation in either age group, we found robust harmful effects of chronic nitrogen dioxide (NO2) exposure in the GxE models for elderly women (16.2 % increase in FeNO, p-value = 0.027). Stratified analyses found GxE effects between the PRS and chronic NO2 exposure in never-smoker elderly women and in adolescents without any inflammatory respiratory conditions. ConclusionsFeNO measurement is a useful biomarker to detect higher risk of NO2-induced eosinophilic airway inflammation in the elderly. There was limited evidence for GxE effects on airway inflammation in adolescents or the elderly. Further GxE studies in subpopulations should be conducted to investigate the assumption that susceptibility to airway inflammation differs between age stages.

Fractional exhaled nitric oxide and mortality in asthma and chronic obstructive pulmonary disease in a national cohort aged 40 years and older

BackgroundLittle is known about Fractional concentration of exhaled Nitric Oxide (FeNO) as a predictor of mortality in persons with asthma or chronic obstructive pulmonary disease (COPD). ObjectiveThis study tested the hypotheses that FeNO level ≥ 25 ppb was associated with mortality in a national cohort of persons with asthma or COPD age ≥ 40 years. MethodsIn the 2007–2012 National Health and Nutrition Examination Survey (NHANES), FeNO was measured using an electrochemical sensor. Mortality was determined through 2015 using linkage to the National Death Index. Weighted Cox proportional hazards survival analysis was performed taking the complex survey design into account using STATA V.17. ResultsAmong the 611 participants with current asthma, 5.16% died during the follow-up period. FeNO ≥ 25 ppb was associated with a hazard ratio (HR) of 0.20, (p = 0.006, 95% CI:0.068–0.618) alone or with little change after controlling for confounding variables. Due to effect modification, the analysis was repeated in persons with and without a history of emergency department (ED) visit for asthma in the previous year. In 522 persons without ED visits, FeNO ≥ 25 ppb was significantly associated with mortality HR 0.094, 95 CI 0.034–0.26, p < 0.001. In 83 persons with ED visits no significant association remained after controlling for all confounders. (Six persons were omitted from this analysis due to missing data on confounders in the extended regression model.) Among 614 with COPD, FeNO ≥ 25 ppb was not associated with mortality. ConclusionIn persons with current asthma at baseline, FeNO ≥ 25 ppb was associated with reduced hazard of mortality during follow up among those with no history of ED visits in the previous year. No significant association of FeNO with mortality was seen in persons with COPD.

Epidemic thunderstorm asthma

Epidemic thunderstorm asthma

Benralizumab Effectiveness in Severe Asthma Is Independent of Previous Biologic Use

Benralizumab is an IL-5 receptor alpha-directed cytolytic mAb that depletes eosinophils, reducing exacerbations and oral corticosteroid (OCS) use, and improves asthma control for patients with severe eosinophilic asthma (SEA). Data on response in patients previously treated with other biologic therapies are limited. To describe real-world clinical outcomes with benralizumab for patients with and without prior biologic use for uncontrolled SEA. This retrospective study compared clinical outcomes before and after benralizumab initiation in adults with uncontrolled SEA with 3 or more asthma exacerbations in the previous 12 months or on maintenance OCS treatment. Outcomes included exacerbations, OCS use, patient-reported outcomes, and health care resource utilization, including emergency department visits and hospitalizations. In all, 208 patients were enrolled, including 90 (43.3%) with previous experience with an alternate biologic for SEA. Benralizumab led to an 81% reduction in exacerbation rate, with 48% of patients with previous exacerbations experiencing none after 48 weeks. Overall, 67% of patients requiring baseline maintenance OCS achieved greater than or equal to 50% reduction in daily OCS dosage, and 53% eliminated maintenance OCS. Clinically meaningful improvements in patient-reported outcomes were seen, with response at 4 weeks predicting longer-term benefits. Health care resource utilization also decreased. Improvements were observed irrespective of previous biologic experience, fractional exhaled nitric oxide concentrations, atopic status, or other baseline characteristics. In a multicenter real-world setting, patients with uncontrolled SEA achieved substantial improvements in all clinical outcome measures with benralizumab irrespective of previous biologic use, atopic status, or baseline fractional exhaled nitric oxide concentration.

Factors Influencing the Concentration of Exhaled Nitric Oxide (FeNO) in School Children Aged 8-9-Years-Old in Krakow, with High FeNO Values ≥ 20 ppb.

Background and Objectives: Measurement of fractional exhaled nitric oxide (FeNO) concentration is currently used as a non-invasive biomarker to assess airway inflammation. Many factors can influence the FeNO level. However, there have been no reports concerning factors attributed to FeNO levels in different age groups of children, especially those with high FeNO values. Therefore, this study aimed to assess the influence of selected factors on nitric oxide concentration in exhaled air in children aged 8–9 attending class 3 of public primary schools in Krakow with high FeNO values ≥ 20 ppb. Materials and Methods: The population-based study covered all third-grade pupils attending primary schools in the city of Krakow. Five thousand, four hundred and sixty children participated in the first screening stage, conducted from October 2017 to January 2018. Then, 792 participants with an FeNO level ≥ 20 ppb were selected. Finally, those selected pupils were invited to participate in the second stage, diagnostic, in April 2018. Four hundred and fifty-four children completed the diagnostic stage of the study, and their data was included in the presented analysis. Results and Conclusions: Significantly higher FeNO levels were observed in children diagnosed with the following diseases: asthma, allergic rhinitis, atopic dermatitis, and allergy (p < 0.05). In addition, it was observed that a higher FeNO concentration characterised children taking antihistamines compared to children not taking those medications (p = 0.008). In multivariate models, we observed that regardless of sex, age, BMI value, home smoking, and whether they were taking medications, children who had allergic rhinitis, or atopic dermatitis, or allergies had significantly higher FeNO levels. The strongest relationship was noted with allergic diseases. The results of our study may be of importance to clinicians when interpreting FeNO results, for example, when making a therapeutic decision.

Pharmacokinetic Profile of Incremental Oral Doses of Dietary Nitrate in Young and Older Adults: A Crossover Randomized Clinical Trial

BackgroundDietary nitrate consumption can increase concentrations of nitrate and nitrite in blood, saliva, and urine. Whether the change in concentrations is influenced by age is currently unknown. ObjectivesWe aimed to measure changes in nitrate and nitrite concentrations in plasma, urine, and saliva and exhaled NO concentrations after single incremental doses of dietary nitrate in young and older healthy adults. MethodsTwelve young (18–35 y old) and 12 older (60–75 y old) healthy, nonsmoking participants consumed single doses of 100 g, 200 g, 300 g whole beetroot (BR) and 1000 mg potassium nitrate (positive control) ≥7 d apart in a crossover, randomized clinical trial. Plasma nitrate and nitrite concentrations and exhaled NO concentrations were measured over a 5-h period. Salivary nitrate and nitrite concentrations were measured over a 12-h period and urinary nitrate over a 24-h period. Time, intervention, age, and interaction effects were measured with repeated-measures ANOVAs. ResultsDose-dependent increases were seen in plasma, salivary, and urinary nitrate after BR ingestion (all P ≤ 0.002) but there were no differences between age groups at baseline (all P ≥ 0.56) or postintervention (all P ≥ 0.12). Plasma nitrite concentrations were higher in young than older participants at baseline (P = 0.04) and after consumption of 200 g (P = 0.04; +25.7 nmol/L; 95% CI: 0.97, 50.3 nmol/L) and 300 g BR (P = 0.02; +50.3 nmol/L; 95% CI: 8.57, 92.1 nmol/L). Baseline fractional exhaled NO (FeNO) concentrations were higher in the younger group [P = 0.03; +8.60 parts per billion (ppb); 95% CI: 0.80, 16.3 ppb], and rose significantly over the 5-h period, peaking 5 h after KNO3 consumption (39.4 ± 4.5 ppb; P < 0.001); however, changes in FeNO were not influenced by age (P = 0.276). ConclusionsBR is a source of bioavailable dietary nitrate in both young and older adults and can effectively raise nitrite and nitrate concentrations. Lower plasma nitrite and FeNO concentrations were found in older subjects, confirming the impact of ageing on NO bioavailability across different systems.This trial was registered at www.isrctn.com as ISRCTN86706442.

Exhaled nitric oxide detection for diagnosis of COVID-19 in critically ill patients.

COVID-19 may present with a variety of clinical syndromes, however, the upper airway and the lower respiratory tract are the principle sites of infection. Previous work on respiratory viral infections demonstrated that airway inflammation results in the release of volatile organic compounds as well as nitric oxide. The detection of these gases from patients' exhaled breath offers a novel potential diagnostic target for COVID-19 that would offer real-time screening of patients for COVID-19 infection. We present here a breath tester utilizing a catalytically active material, which allows for the temporal manifestation of the gaseous biomarkers' interactions with the sensor, thus giving a distinct breath print of the disease. A total of 46 Intensive Care Unit (ICU) patients on mechanical ventilation participated in the study, 23 with active COVID-19 respiratory infection and 23 non-COVID-19 controls. Exhaled breath bags were collected on ICU days 1, 3, 7, and 10 or until liberation from mechanical ventilation. The breathalyzer detected high exhaled nitric oxide (NO) concentration with a distinctive pattern for patients with active COVID-19 pneumonia. The COVID-19 "breath print" has the pattern of the small Greek letter omega (). The "breath print" identified patients with COVID-19 pneumonia with 88% accuracy upon their admission to the ICU. Furthermore, the sensitivity index of the breath print (which scales with the concentration of the key biomarker ammonia) appears to correlate with duration of COVID-19 infection. The implication of this breath tester technology for the rapid screening for COVID-19 and potentially detection of other infectious diseases in the future.