Development and validation of exhaled breath condensate microRNAs to identify and endotype asthma in children

Abstract

Detection and quantification of microRNAs (miRNAs) in exhaled breath condensate (EBC) has been poorly explored. Therefore we aimed to assess miRNAs in EBC as potential biomarkers to diagnose and endotype asthma in school aged children. In a cross sectional, nested case control study, all the asthmatic children (n = 71) and a random sample of controls (n = 115), aged 7 to 12 years, attending 71 classrooms from 20 local schools were selected and arbitrarily allocated to the development or validation set. Participants underwent skin-prick testing, spirometry with bronchodilation, had exhaled level of nitric oxide determined and EBC collected. Based on previous studies eleven miRNAs were chosen and analyzed in EBC by reverse transcription-quantitative real-time PCR. Principal component analysis was applied to identify miRNAs profiles and associations were estimated using regression models. In the development set (n = 89) two clusters of miRNAs were identified. After adjustments, cluster 1 and three of its clustered miRNAs, miR-126-3p, miR-133a-3p and miR-145-5p were positively associated with asthma. Moreover miR-21-5p was negatively associated with symptomatic asthma and positively associated with positive bronchodilation without symptoms. An association was also found between miR-126-3p, cluster 2 and one of its clustered miRNA, miR-146-5p, with higher FEF25-75 reversibility. These findings were confirmed in the validation set (n = 97) where two identical clusters of miRNAs were identified. Additional significant associations were observed between miR-155-5p with symptomatic asthma, negative bronchodilation with symptoms and positive bronchodilation without symptoms. We showed that microRNAs can be measured in EBC of children and may be used as potential biomarkers of asthma, assisting asthma endotype establishment.

The Role of T Cells and Macrophages in Asthma Pathogenesis: A New Perspective on Mutual Crosstalk

“…miRNA-126 was found to be higher in peripheral blood exosomes from asthmatic patients, correlated with the elevation of IL-4 and IgE [ 156 ]. It was indicated that miRNA-21 was lower in exosomes isolated from the exhaled breath condensate of asthmatic patients that increased Th2 cells and diminished Th1 cells [ 157 ]. Also, a higher expression of exosomal miRNA-155 in mild asthmatic patients seems to break the equilibrium of Th1/Th2 [ 158 , 159 ].…”

Role of extracellular vesicles in chronic lung disease

“…Similarly to the Héliot study of COPD, Levänen found that the let-7 family of nucleotides were among the most significantly downregulated in asthmatics. 97 Mendes et al 98 used breath condensate to investigate a potential miRNA based platform for asthmatic endotyping. Let-7 and other miRNAs were shown in exhalate, in sufficient quantity and with a significant difference, to enable potential phenotyping of asthmatic children.…”

“…Let-7 and other miRNAs were shown in exhalate, in sufficient quantity and with a significant difference, to enable potential phenotyping of asthmatic children. 98 Duarte et al 64 conducted one of the first investigations of EVs as biomarkers for asthma. They found that EVs levels were significantly increased in asthmatics and found strong but not significant indications of inflammatory markers.…”

Exhaled Breath Condensate—A Non-Invasive Approach for Diagnostic Methods in Asthma

“…A recent study by Mendes et al showed a possibility to assess asthma endotypes in EBC material of pediatric patients through miRNAs. Certain miRNAs were associated with symptomatic asthma and correlated with bronchodilator response [ 114 ].…”