Extracellular DNA in sputum is associated with pulmonary function and hospitalization in patients with cystic fibrosis

Piva, Taila Cristina; Luft, Carolina; Antunes, Krist Helen; Maróstica, Paulo José Cauduro; Pinto, Leonardo Araújo; Donadio, Márcio Vinı́cius Fagundes

doi:10.1016/j.rmed.2020.106144

Cited by 18 publications

(20 citation statements)

References 39 publications

(55 reference statements)

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“…Accordingly, we also observed increased air trapping and ventilation heterogeneity in high-eDNA patients. Our findings regarding the correlation of sputum e-DNA with airflow obstruction are consistent with previous findings from patients with chronic obstructive pulmonary disease (COPD) [ 28 ] and cystic fibrosis (CF) [ 29 ]. It has been suggested that increased e-DNA production in the airways contributes to airflow obstruction by increasing the airway secretions [ 30 ] and mucus viscoelasticity [ 31 ], and by the contribution to airway inflammation through both activated proteases [ 32 ] and the proinflammatory cytokines [ 6 ].…”

Section: Discussionsupporting

confidence: 91%

Raised sputum extracellular DNA confers lung function impairment and poor symptom control in an exacerbation-susceptible phenotype of neutrophilic asthma

et al. 2021

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Background Extracellular DNA (e-DNA) and neutrophil extracellular traps (NETs) are linked to asthmatics airway inflammation. However, data demonstrating the characterization of airway inflammation associated with excessive e-DNA production and its impact on asthma outcomes are limited. Objective To characterize the airway inflammation associated with excessive e-DNA production and its association with asthma control, severe exacerbations and pulmonary function, particularly, air trapping and small airway dysfunction. Methods We measured e-DNA concentrations in induced sputum from 134 asthma patients and 28 healthy controls. We studied the correlation of e-DNA concentrations with sputum neutrophils, eosinophils and macrophages and the fractional exhaled nitric oxide (FeNO). Lung function was evaluated using spirometry, body plethysmography, impulse oscillometry and inert gas multiple breath washout. We stratified patients with asthma into low-DNA and high-DNA to compare lung function impairments and asthma outcomes. Results Patients with severe asthma had higher e-DNA concentration (54.2 ± 42.4 ng/µl) than patients with mild-moderate asthma (41.0 ± 44.1 ng/µl) or healthy controls (26.1 ± 16.5 ng/µl), (all p values < 0.05). E-DNA concentrations correlated directly with sputum neutrophils (R = 0.49, p < 0.0001) and negatively with sputum macrophages (R = − 0.36, p < 0.0001), but neither with sputum eosinophils (R = 0.10, p = 0.26), nor with FeNO (R = − 0.10, p = 0.22). We found that 29% of asthma patients (n = 39) had high e-DNA concentrations above the upper 95th percentile value in healthy controls (55.6 ng /μl). High-DNA was associated with broad lung function impairments including: airflow obstruction of the large (FEV1) and small airways (FEF50%, FEF25–75), increased air trapping (RV, RV/TLC), increased small airway resistance (R5-20, sReff), decreased lung elasticity (X5Hz) and increased ventilation heterogeneity (LCI), (all P values < 0.05). We also found that high e-DNA was associated with nearly three-fold greater risk of severe exacerbations (OR 2·93 [95% CI 1.2–7.5]; p = 0·012), worse asthma control test (p = 0.03), worse asthma control questionnaire scores (p = 0.01) and higher doses of inhaled corticosteroids (p = 0.026). Conclusion Increased production of extracellular DNA in the airway characterizes a subset of neutrophilic asthma patients who have broad lung function impairments, poor symptom control and increased risk of severe exacerbations.

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Section: Discussionsupporting

confidence: 91%

Raised sputum extracellular DNA confers lung function impairment and poor symptom control in an exacerbation-susceptible phenotype of neutrophilic asthma

et al. 2021

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“…Sputum processing was performed at the Pediatric Respirology Laboratory (Centro Infant, PUCRS), as previously described. 8 In brief, the sample was homogenized in dithiothreitol (DTT) and Dulbecco's phosphate-buffered saline (DPBS), followed by the filtration and centrifugation process. For DNA analysis, the supernatant was precipitated in absolute ethanol and 3M sodium acetate and incubated overnight at −20℃.…”

Section: Quantification Of Extracellular Dnamentioning

confidence: 99%

“…A recent study showed that subjects with levels of DNA in the sputum greater than 243 μg/mL had a significant decrease in forced expiratory volume in the first second (FEV 1 ) and greater need for hospitalisation. 8…”

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“…Considering that there are no previous studies that evaluated the association between free DNA levels in the sputum and aerobic fitness, we used lung function data to estimate the necessary sample size. 8 Considering an expected correlation between variables from 0.5 to 0.7, a significance level of 0.05, and a power of 80%, an approximate sample size of 15 subjects was estimated. This study was approved by the Ethics Committee of Pontifícia Universidade Católica do Rio Grande Do Sul (CAAE: 91277118.5.0000.5336).…”

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confidence: 99%

“…11 For sputum collection, subjects who used dornase alfa (Pulmozyme ® , Roche) were recommended to wait at least 12 hours between nebulisation and the collection procedure, because of the drug's action on DNA. As previously described, 8 in order to avoid contamination of the sample, subjects were instructed to clean the mouth beforehand to remove the superficial bacterial flora. After, participants were asked to spontaneously expectorate in a sterile container.…”

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Aerobic fitness is associated with extracellular DNA levels in the sputum of patients with cystic fibrosis

et al. 2021

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Cystic fibrosis (CF) is a genetic disease that affects multiple organs and systems. It is characterized by a progressive decline in pulmonary function and by the presence of exercise intolerance, which is associated with airway obstruction and the presence of chronic inflammation and recurrent infections. 1,2 Elevated levels of extracellular DNA, mainly originating from neutrophil extracellular traps (NETs), have been described in both bronchoalveolar lavage and sputum of CF patients. [3][4][5] The presence of DNA changes the viscosity and elasticity of the mucus, contributing to airway obstruction. In addition to this, the presence of chronic airway neutrophilic inflammation is considered an important factor for the early development of lung disease. 6 DNA levels in airway fluid samples from individuals with CF are already known to negatively correlate with lung function. 7 This suggests that the DNA found in airway fluids may contribute to lung disease from the beginning of life. A recent study showed that subjects with levels of DNA in the sputum greater than 243 μg/mL had a significant decrease in forced expiratory volume in the first second (FEV 1 ) and greater need for hospitalisation. 8

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Metagenomics in the Census of Microbial Diversity

Hora,

Mani

2024

Multi-Omics Analysis of the Human Microbiome

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Extracellular DNA in sputum is associated with pulmonary function and hospitalization in patients with cystic fibrosis

Cited by 18 publications

References 39 publications

Raised sputum extracellular DNA confers lung function impairment and poor symptom control in an exacerbation-susceptible phenotype of neutrophilic asthma

Raised sputum extracellular DNA confers lung function impairment and poor symptom control in an exacerbation-susceptible phenotype of neutrophilic asthma

Aerobic fitness is associated with extracellular DNA levels in the sputum of patients with cystic fibrosis

Metagenomics in the Census of Microbial Diversity

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