Extrazelluläre Vesikel im Sputum von Kindern mit zystischer Fibrose und pulmonaler Exazerbation

Introduction Extracellular vesicles (EVs) are nano-sized particles released from different cell types that play critical roles in intercellular communication and disease pathogenesis. The aim of this study was to isolate and characterize EVs from airway secretions of children with cystic fibrosis (CF), and to quantify changes in neutrophil elastase (NE) and myeloperoxidase (MPO) content during CF pulmonary exacerbation (PEx).

Methods EVs were isolated from expectorated sputum samples collected before and after 14 days of intravenous antibiotic therapy for PEx. EVs were characterized by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM), following international guidelines. Western blot analysis of EV protein extracts was used to quantify expression of EV canonical protein markers CD-63, CD-9, and flotillin-1 (FLOT1), as well as NE and MPO.

Results Samples of twelve children 8.0 to 16.9 years of age were included, of which six had positive sputum cultures for Staphylococcus aureus and six for Pseudomonas aeruginosa. Mean (SD) percent predicted forced expiratory volume in 1 second (ppFEV1) was 60.2 (8.9) before and 72.2 (10.8) after therapy for PEx (p<0.01). CD63, CD9 and FLOT1 protein were detectable in all sputum samples. NTA showed high concentrations of particles at the expected size of small EVs (50-200 nm), and TEM confirmed nano sized vesicles with typical EV morphology. The MPO/FLOT1 ratio increased from 3.22 (1.36) before to 5.45 (1.67) after therapy (p<0.01), and NE/FLOT1 from 3.44 (1.84) to 6.44 (3.95) (p=0.01). Changes in ppFEV1 with therapy correlated with changes in NE/FLOT1 (r=0.68, p=0.015), but not MPO/FLOT1 ratio.

Conclusions Airways of children with CF contain large quantities of EVs that carry MPO and NE as cargo. The observed changes in NE and MPO content in the EVs with antibiotic therapy suggests a role of airway EVs in CF lung disease and greater release of EV proteases during acute PEx.

Conflict of Interest

No

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Publication History

Article published online:
21 September 2022