Detection of bacterial extracellular vesicles in patients with cystic fibrosis - a pilot study.

BACKGROUND AND AIMS: Pseudomonas (P.) aeruginosa is an opportunistic pathogen closely linked to Cystic Fibrosis (CF). Recent publications emphasize that an accumulation of bacterial derived extracellular vesicles within the circulation might be associated with the pathogenesis of various chronic inflammatory diseases and could potentially be used as diagnostic tool.

METHODS

Bacterial extracellular vesicles (bEVs) were isolated and characterized via Nanoparticle Tracking Analysis (NTA) and Transmission Electron Microscopy (TEM) from plasma samples of persons with CF (pwCF) without infection with P. aeruginosa (PsA-, n = 31), pwCF with confirmed P. aeruginosa infection (PsA+, n = 29), and control individuals (HC, n = 30). Size and concentration of bEVs were evaluated and correlated with clinical parameters. Western blot analyses were implemented to study the species-specific origin of bEVs, using lysates and reference vesicles.

RESULTS

bEVs could be detected in all samples from both, HC and pwCF. Relative NF‑κB induction, assessed via a TLR4 reporter assay, was significantly elevated in pwCF than in HC, with the strongest responses observed in PsA+ patients. emphasize bEV-associated activity. Surprisingly, CFTR modulator treatment (ETI) enhanced LPS concentration of bEVs in pwCF independent of P. aeruginosa colonization. Moreover, NF-kB induction correlated negatively with serum IgA levels in PsA+ patients. Direct detection of bEVs in plasma samples via Western blot was technically not possible.

CONCLUSION

Our findings suggest a potential link between pulmonary P. aeruginosa colonization and increased systemic bEVs-associated activity as potential consequence of deficient mucosal barrier function. However, further research is required in order to validate our findings and to clarify the influence of ETI on bEV accumulation.