Correlation between fractional exhaled nitric oxide and Asthma Control Test score and spirometry parameters in on-treatment-asthmatics in Ho Chi Minh City

Relationship between fraction of exhaled nitric oxide and peripheral eosinophilia in asthma

BACKGROUND

Achieving disease control is the goal of asthma management. Serum or sputum eosinophil counts have been known traditional means of assessing eosinophilic airway inflammation in asthma, which is vital in predicting response to corticosteroid therapy which ultimately promotes control of the disease. Evidence suggests that fraction of exhaled nitric oxide (FeNO) may be a more useful non-invasive surrogate biomarker for the assessment of eosinophilic airway inflammation and could help with the timely adjustment of inhaled corticosteroid therapy in the uncontrolled asthma patient. The relationship between FeNO and other markers of airway inflammation has been variable in literature, with limited data in sub-Saharan Africa where FeNO testing is very sparse. We sought to define the relationship between FeNO levels, serum eosinophil counts, spirometry measures and symptom control among asthma patients.

MATERIALS AND METHODS

The study was conducted at the Asthma Clinic of a large tertiary hospital. This study included 82 patients with physician-diagnosed asthma being regularly managed at the clinic. All participants were taken through the asthma control test (ACT), had FeNO and spirometry measurements taken according to the American Thoracic Society (ATS) guidelines. Blood samples were obtained from all participants for serum eosinophil counts. Correlation coefficient was used to ascertain the relationship between FeNO levels and serum eosinophil counts, ACT scores, and spirometry measurements. Logistic regression was used to examine the association between high FeNO and abnormal FEV1 percentage predicted (<80%) with adjustments for age, sex, and BMI.

RESULTS

A total of 82 patients with asthma were included in the study, with higher prevalence of females (72%). Majority (40.2%) of the patients were found in the 60 and above age category. The median FeNO level and ACT score was 42.00 (26.00-52.50) parts per billion (ppb) and 20.0 (18-23) respectively. The median serum eosinophil counts was 0.25(0.90-0.38) × 109/L. The median FeNO levels were significantly higher in patients with partly and very poorly controlled asthma than in the well-controlled group (p < 0.001). A total of 47(57%) of the patients were classified as having well controlled asthma and 35 (42%) uncontrolled. FeNO correlated with serum eosinophil counts (r = 0.450, p < 0.001), ACT (r = -0.648, p < 0.001), and FEV1 percentage predicted (r = -0.353, p = 0.001). High FeNO (>50 ppb) was associated with an over fivefold increased risk of having an abnormal FEV1 percentage predicted.

CONCLUSION

FeNO levels significantly correlated with the ACT scores, serum eosinophil counts and FEV1% predicted among the asthma patients who were on inhaled corticosteroid therapy. High FeNO was significantly associated with abnormal FEV1 percentage predicted. We suggest that the point of care assessment of FeNO is a reliable marker of eosinophilic inflammation in our cohort of patients and together with 'ACT scores' in our asthma clinics could increase asthma control rates.

Association between Childhood Asthma Control Test scores and lung pathophysiologic indicators in longitudinal measurements

Background

Childhood Asthma Control Test (C-ACT) is a well-validated questionnaire for asthma controls among 4-11 years old children. This study aims to examine if longitudinal C-ACT score changes could also reflect lung pathophysiologic changes.

Methods

Thirty-seven children (43% female) aged 5 to 10 years old with mild or moderate asthma were followed up for 6 weeks with bi-weekly assessments of C-ACT, airway mechanics, lung function and respiratory inflammation. Associations of longitudinal changes in C-ACT score with lung pathophysiologic indicators were evaluated using linear mixed-effects models.

Results

A two-point worsening of total C-ACT score (sum of child and caregiver-reported) was associated with significant decreases in forced expiratory volume during the 1st second (FEV1) by 1.7% (P=0.04) and forced vital capacity (FVC) by 1.6% (P=0.01) and increased total airway resistance [airway resistance at 5 Hz (R5)] by 3.8% (P=0.05). A two-point worsening in child-reported score was significantly associated with 3.1% and 2.5% reductions in FEV1 and FVC, respectively, and with increases in R5 by 6.5% and large airway resistance [airway resistance at 20 Hz (R20)] by 5.5%. In contrast, a two-point worsening of caregiver-reported score was associated with none of the concurrent lung pathophysiologic measurements. Worsening of total C-ACT score was significantly associated with increased respiratory inflammation [fractional exhaled nitric oxide (FeNO)] in a subset (n=23) of children without eosinophilic airway inflammation. C-ACT scores were associated with none of the small airway measures.

Conclusions

In children with mild or moderate asthma, longitudinal C-ACT score changes could reflect acute changes in large airway resistance and lung function. Measures of small airway physiology would provide valuable complementary information for asthma control. Asthma phenotype may affect whether C-ACT score could reflect respiratory inflammation.

Assessment of Fraction of Exhaled Nitric Oxide and Soluble Receptor for Advanced Glycation End Products Biomarkers for Jordanian Asthmatic Children

PURPOSE

Fraction of exhaled nitric oxide (FeNO) and soluble advanced glycation end-product receptor (sRAGE) are proposed as biomarkers of asthma, therefore we sought to assess their use in asthmatic children of Jordan.

PATIENTS AND METHODS

We conducted a case-control study at The University of Jordan Hospital. A total of 141 asthmatic children followed by respiratory pediatricians and 118 healthy children aged 4-18 years were recruited. FeNO was measured by NObreath device and serum sRAGE by ELISA that detect endogenously soluble isoform (esRAGE) and total soluble RAGE (sRAGE).

RESULTS

sRAGE in asthmatic was half of the control (p <0.001). In addition, ratio of esRAGE/sRAGE was two-fold higher in asthmatic (p = <0.001). Neither FeNO nor esRAGE levels were significantly different between groups. FeNO and asthma control test (ACT) score were negatively correlated corrected for age and body mass index (BMI), (r = -0.180, p= 0.034). For the uncontrolled asthma group, esRAGE/sRAGE negatively correlated with ACT score (r = -.329, p = 0.038). Receiver operating curve (ROC) analysis revealed significant predictive value (PV) for sRAGE and esRAGE/sRAGE in asthma detection with area under the curve (AUC) of (0.751 ± 0.031) and (0.711±.033), consequently. However, no biomarker had a significant PV for lack of control.

CONCLUSION

The current study supports utilizing sRAGE as a marker for asthma and present a potential therapeutic target. However, our results indicate that both FeNO and sRAGE have a limited role in the management of asthmatic children or assessment of asthma control.

MMEF25-75 may predict significant BDR and future risk of exacerbations in asthmatic children with normal baseline FEV1

(1) Background: Several recent studies on the clinical value of spirometry indexes demonstrated high sensitivity of FEF25-75 as a marker of bronchial obstruction in asthmatics with normal baseline spirometry. Our study aims to evaluate the clinical value of maximal mid-expiratory flow in children with asthma. (2) Methods: For two years, 257 children were included - 211 with asthma and 46 healthy controls. Pre- and post-bronchodilator spirometry, atopic status determination and asthma control assessment were performed. (3) Results: The small airway obstruction (SAO) group (FEV1≥80%, ММEF25/75<65%) demonstrated significantly lower values for FEV1, FEV1/FVC, PEFR, МMMF25/75 and a significant higher bronchodilator response (BDR, ΔFEV1% init. ≥12%) compared to normal baseline spirometry group (FEV1>80%, MMEF25/75≥65%) (Р<0.0001). In addition, we found a statistically significant difference in FEF25-75/FVC median between asthmatics and healthy controls (Р<0.0001) regardless of the FEV1 value. Children with SAO have a 2.338-fold higher risk of poor asthma outcome (OR 95% CI [1.077-5.294]) and a 6.171-fold (OR 95% CI [2.523-15.096]) greater probability of demonstrating positive BDR, compared to children with normal baseline spirometry. MMEF25/75 was found to be a good predictor for positive BDR with AUC 0.843 (CI 0.781-0.845) and a best cut-off value of 58.1% (77.8% sensitivity and 78.8% specificity). (4) Conclusion: Our results confirmed that a small but substantial group of asthmatic children with normal baseline FEV1 and low MMEF25-75 are at higher risk for poor asthma outcomes.

Asthma phenotype: Clinical, physiological, and biochemical profiles of North Indian patients

Background and Objectives:

Asthma is a common, chronic and heterogeneous disease with various phenotypes. The clinical phenotypes has aided in revealing the genetic heterogeneity, provide education, life style advice and novel biological treatments. The few common factors associated with phenotypes are smoking, rhinitis and obesity. The present study was thus planned to analyse and correlate the clinical, physiological, biochemical and serological parameters of asthma and to study the phenotypic characteristics in different asthmatic.

Methods:

This was a prospective observational study of 120 patients with 30 each in BA-rhinitis, BA, BA-obesity and BA smoker phenotypes. All the enrolled patients were assessed by SGRQ, Mini-AQLQ, GINA with ACE, chest X ray, Spirometry, SPT against common aero-allergens, FENO, hsCRP, vitamin-D, IgE, and Interleukins (IL) including IL-5, IL-6, IL-8, IL-13, IL-17 and IL-33. The mentioned profiles of each phenotype correlated and characterized among different phenotypes.

Results:

The majority of patients 78(65%) were female with mean BMI of 24.07±4.73kg/m². Majority of the patient in BA and BA-rhinitis phenotype are in mild severity and young compared to majority in BA-obesity and BA-smoker are moderate to severe severity with older. (p<0.001) The SPT and FENO level were highest among BA-rhinitis phenotype with significant difference among phenotypes. (p<0.001) Similarly the most of inflammatory markers were significantly different in various phenotypes. The FEV1 showed correlation with most of parameters with statistically significant correlation with IL-5, IL-8 and FENO.

Conclusion:

The majority of parameters were significantly different among various phenotypes. We advise to phenotypic classification of asthma whenever possible for better management and quality of life.

Redox Role of ROS and Inflammation in Pulmonary Diseases

Reactive oxygen species (ROS), either derived from exogenous sources or overproduced endogenously, can disrupt the body's antioxidant defenses leading to compromised redox homeostasis. The lungs are highly susceptible to ROS-mediated damage. Oxidative stress (OS) caused by this redox imbalance leads to the pathogenesis of multiple pulmonary diseases such as asthma, chronic obstructive pulmonary disease (COPD), and acute respiratory distress syndrome (ARDS). OS causes damage to important cellular components in terms of lipid peroxidation, protein oxidation, and DNA histone modification. Inflammation further enhances ROS production inducing changes in transcriptional factors which mediate cellular stress response pathways. This deviation from normal cell function contributes to the detrimental pathological characteristics often seen in pulmonary diseases. Although antioxidant therapies are feasible approaches in alleviating OS-related lung impairment, a comprehensive understanding of the updated role of ROS in pulmonary inflammation is vital for the development of optimal treatments. In this chapter, we review the major pulmonary diseases-including COPD, asthma, ARDS, COVID-19, and lung cancer-as well as their association with ROS.